: Spring Bulbs

Helo gyfeillion y gwanwyn,

Mae’n amser diddorol i astudio ac arsylwi ar y tywydd! Bydd y rhan fwyaf ohonoch wedi gweld eira a gwyntoedd uchel yr wythnos ddiwethaf. Rwy'n deall bod llawer o ysgolion wedi'u cau, a hyd yn oed os oedd eich ysgol ar agor efallai ei bod hi’n rhy beryglus i gymryd darlleniadau tywydd.

Mae'n debyg byddwch chi wedi clywed pobl yn sôn am rybuddion tywydd dros yr wythnos ddiwethaf. Caiff rhybuddion tywydd eu rhyddhau gan swyddfa’r MET (gwasanaeth tywydd swyddogol y DU) gyda chod lliw (gwyrdd, melyn, ambr a choch) i ddangos pa mor eithafol fydd y tywydd mewn gwahanol ardaloedd.

Gwyrdd: dim tywydd garw.

Melyn: posibilrwydd o dywydd eithafol, gofalwch.

Ambr (oren): posibilrwydd cryf y bydd y tywydd yn effeithio arnoch chi mewn rhyw fodd, paratowch.

Coch: yn disgwyl tywydd eithafol, cynllunio ymlaen llaw a dilyn cyngor y gwasanaethau brys ac awdurdodau lleol.

Mae’r Swyddfa Dywydd hefyd yn defnyddio symbolau i ddangos pa fath o dywydd i’w ddisgwyl. Dyma symbolau yn dangos rhybudd coch am law, rhybudd gwyrdd am wynt ac eira, rhybudd ambr am iâ a rhybudd gwyrdd am niwl. Mae hyn yn golygu bydd hi'n bwrw glaw yn drwm a dylech chi baratoi am iâ. Beth am edrych ar y tywydd lleol ar wefan y Swyddfa Dywydd?

Yr wythnos diwethaf gwelodd rhai ardaloedd rybuddion ambr a choch ar gyfer gwynt, eira a rhew oherwydd storm Emma a’r 'Dihiryn o'r Dwyrain’. Mae swyddfa’r MET yn ein rhybuddio er mwyn i ni baratoi am dywydd garw. Gall tywydd garw (fel gwynt cryf ac iâ) achosi problemau a’i gwneud hi’n anodd teithio. Weithiau bydd ffyrdd, rheilffyrdd a hyd yn oed ysgolion yn cau oherwydd tywydd gwael.

Pa fath o dywydd weloch chi yr wythnos diwethaf? Os nad oeddech chi’n gallu casglu cofnodion tywydd, nodwch 'dim cofnod' ar y ffurflen, a dweud yn yr adran sylwadau pa fath o dywydd weloch chi! Gallwch chi hefyd roi gwybod sut hwyl sydd ar eich planhigion, ac a ydynt wedi blodeuo?

Daliwch ati gyda'r gwaith da gyfeillion,

Athro’r Ardd

Sylwadau am y tywydd:

Ysgol Beulah: Roedd eira yn pot ni :)!!!!!!!!!.

Ysgol Carreg Emlyn: Mae hi wedi bwrw eira yma heddiw.

Ferryside V.C.P School: mae wythnos hyn wedi bod yn bwrw lot

Broad Haven Primary School: Snow Hail sleet sun rain gales . We have seen them all.

St Robert's R.C Primary School: We had a cold week this week.

Peterston super Ely Primary School: Lots of snow on Friday

Steelstown Primary School: Once again northern Ireland has been hit by a cold patch but Derry has once again missed out on heavy snowfall roll on spring.

Severn Primary: Some other places got some snow and it was really cold on Thursday when we went out for Games because of the wind. Hope we get snow!

St Paul's CE Primary School: WINDY AND COLD SNOW SHOWERS

Canonbie Primary School: We had snow again this week and lots of rain. Little signs of life springing through but no flowering bulbs yet.

Canonbie Primary School: This week has been a bit mixed weather wise. We had freezing conditions and snow on Tuesday but milder conditions by Friday. Typical British weather.

Carnbroe Primary School: Hi Professor Plant, we were off all week except for Thursday and Friday. The weather this week has been cold and icy.

Peterston super Ely Primary School: Snow days on Thursday and Friday

Onthank Primary School: No record of result due to snow days.

Auchenlodment Primary School: The Beast from the East hit this week! There was lots of snow and we were off school, yippee!

St John's Primary School: School was closed on Thursday due to weather conditions.

Fleet Wood Lane Primary School: School closed because of snow on Weds – Fri.

Carnforth North Road Primary School: The weather this week has been very cold and windy. The children have had to wrap up warm to gather the data.

Portpatrick Primary School: Very cold first thing - frozen ground, but no snow.

Inverkip Primary School: Hi professor plant Monday we had ALOT of rain but every other day it didn't rain at all. The temperature was warm then it dropped down but steadied up at the end of the week.

Steelstown Primary: We are starting to get some warm weather and some of our bulbs are growing.

Arkholme CE Primary School: It was very cold and on some days it was frosty.

St Andrew's RC Primary School: The rain gauge was broken by the frost, we have ordered a new one. This is why we have no rainfall for Wednesday, Thursday or Friday.

Sylwadau am eich planhigion:

Ysgol Beulah: Roedd y tywydd yn oer iawn felly dydy'r blodau ddim wedi blaguro eto.

Ysgol Y Traeth: Mae sawl un o'r blodau wedi dechrau tyfu a rhai wedi dechrau agor yn araf. Mae 14 crocws wedi tyfu a 27 daffodil wedi tyfu.

Carnbroe Primary School: Hi Professor Plant, our bulbs still have not bloomed yet. The weather this week has been changeable. It has been wet, really really cold and icy and although the sun is out it's been cold.

Ysgol Bro Pedr: Many bulbs making an appearance now - a very cold week

Peterston super Ely Primary School: Meghan's crocus has finally flowered! Hopefully when we return from our half term holiday a few more will have flowered too.

Peterston super Ely Primary School: The children are very excited this week as one of our crocus bulbs has finally flowered!

Darran Park Primary: The temperature is still very cold. Our daffodils haven't grown but our crocus have a little bit.

Inverkip Primary School: Mon - Wed school holidays so no data collected. The bulbs are growing well in the pots but not in the ground yet. None have started to flower.

Pembroke Primary School: Looks like I planted two crocus and 1 daffodil. When I saw mine I was surprised.

Pembroke Primary School: This was the first in our class. T has now left the school. The pot wasn't full to the top with compost so this may have resulted in it flowering early.

Auchenlodment Primary School: Got colder this week with very little rainfall. Most of the bulbs have begun to sprout!

Stanford in the Vale Primary School: Beautiful deep purple flower.

Ysgol Bro Pedr: The first crocus opened over our half term.

Bacup Thorn Primary School: Monday and Tuesday were teacher training days at Thorn. We are back and ready to measure! The children noticed some of our bulbs are making a slight appearance!!

Helo Gyfeillion y Gwanwyn,

Rwy am rannu ambell lun gyda chi. Cofiwch, os gofynnwch i’ch athro neu athrawes yrru lluniau o’ch planhigion i mi, gallaf eu rhannu gydag ysgolion eraill sy’n rhan o’r project! Mae gen i ddiddordeb mawr mewn lluniau sy’n dangos y newid mewn tymhorau – fel blodau’r gwanwyn yng nghanol eira’r gaeaf!

Mae rhywfaint o ddryswch wedi bod ynghylch pryd i gofnodi dyddiad blodeuo ar-lein. Gallwch fonitro taldra eich planhigion bob wythnos a gadael i mi wybod yn yr adran ‘sylwadau’ wrth i chi gofnodi’r tywydd. Ond dim ond wedi i’r planhigyn flodeuo y dylech gofnodi ‘dyddiad blodeuo’ a thaldra’r planhigyn.

Edrychwch ar y llun o Gennin Pedr yn Sain Ffagan. Cafodd y llun ei dynnu ar ddiwrnod oer, felly nid oedd y blodau wedi agor yn llawn. Ond, gallwch weld pa rai sydd wedi blodeuo trwy edrych yn ofalus. Os yw’r holl betalau i’w gweld yn glir yna mae’r planhigyn wedi blodeuo. Cyn blodeuo mae’r petalau yn cael eu gwarchod gan gasyn tynn o enw blagur.

Pan fydd y blodyn wedi aeddfedu, a’r tywydd yn ddigon cynnes, bydd y casyn yn dechrau agor. Gall hyn gymryd ychydig oriau neu rai dyddiau! Efallai y gallwch weld hyn yn digwydd, os wnewch chi wylio’r planhigion yn ofalus iawn! Pan fyddwch yn gallu gweld yr holl betalau a’r casyn wedi disgyn gallwch fesur taldra’r blodau a chofnodi hyn ar y wefan. Wedi i chi wneud hynny bydd y cylch sy'n dangos lle mae eich ysgol ar y map yn newid llyw.

Ydych chi wedi cymharu uchder y blodau yn eich dosbarth? Oes yna wahaniaeth mawr yn uchder y planhigion a pha mor aeddfed ydyn nhw, neu ydyn nhw i gyd yn debyg? Beth am y planhigion sydd wedi’u plannu yn y ddaear? Yw’r rhain yn fwy na’r rhai mewn potiau? Pam hynny tybed? Gallwch ddweud beth ydych chi’n feddwl yn yr adran ‘sylwadau’ wrth i chi gofnodi’r tywydd yr wythnos hon!

Gyrrwch eich straeon a lluniau i’r blog blodau a dilynwch Athro’r Ardd ar Twitter!

Daliwch ati Gyfeillion y Gwanwyn!

Athro’r Ardd

Eich sylwadau:

Ysgol Y Traeth: Yn anffodus mae ein thermomedr wedi torri yn gwyntoedd cryfion rydym yn aros am un newydd i gyrraedd.

Ysgol Beulah: Roedd llawer o law dros y penwythnos.

Arkholme CE Primary School: Some of the bulbs have spouted and some have not. We have not had much rain or much warmth either. The average temperature has been 5 degrees and the rain has been 3 ml. L and E.

Professor Plant: Wow Bulb Buddies, thank you for your update. I’m impressed to have the average temperature and rainfall for the week. Keep up the fantastic work!

Steelstown Primary School: Happy New Year, still enjoying the bulb project, lots of little sprouts are coming up now.

Carnforth North Road Primary School: Bulbs have started to grow in pots and in the ground as well.

Inverkip Primary School: The water was frozen on Friday. The bulbs have started to grow.

Carnforth North Road Primary School: Lots of Crocus are growing but not very many daffodils.

Ysgol Bro Pedr: A few buds beginning to show their heads above ground this week - happy days.

Tonyrefail Primary School: Two of our pots have got shoots coming through.

Pembroke Primary School: Approximately half crocus and a few daffodils now showing.

Nant y Moel Primary: Our bulbs have started to grow, we are getting excited.

Henllys CIW: Monday was 26 mm and shoots are starting to come up.

Carnbroe Primary School: Hi Professor Plant on Wednesday the rain was very heavy and the temperature begun to rise. Today it was very frosty and icy. Hopefully our bulbs will begin to grow soon.

Glenluce Primary School: We are building an ark in Glenluce!

Professor Plant: Gosh Glenluce Primary, that sounds exciting! Please share photos of your ark!

Glenluce Primary School: Snow day Friday, great snowball fights!

St Teresa's Primary School: We were closed on Wednesday due to snow.

Biggar Primary School: Due to snow the school was closed and no data was collected for 3 days.

St. Columbkille's Primary School: Heavy snow and school closures meant pupils were unable to get readings for some days.

Stanford in the Vale Primary School: Very cold week!

Am dywydd diddorol Gyfeillion y Gwanwyn!

Wrth edrych trwy ein canlyniadau o 2011 i 2017 (gan ddefnyddio'r siart ar y dde), gallwn weld fod Tachwedd a Rhagfyr 2017 wedi cael tymheredd a glawiad llai na'r cyfartalog, ond oriau o haul uchaf na'r cyfartalog! Drwy gymharu'r data ar gyfer 2017 gyda blynyddoedd blaenorol, gallwn weld cafodd Tachwedd a Rhagfyr 2017 yr oriau o haul trydydd uchaf ers i ni gychwyn ein cofnodion.

Beth am weithio allan eich darlleniadau cyfartalog ar gyfer mis Tachwedd a Rhagfyr a chymharu heu’n hefo’r darlleniadau yn y tabl?

Mae nifer ohonoch wedi rhoi gwybod bod eich planhigion wedi cychwyn tyfu! Ydych chi'n meddwl y bydd y Crocws neu’r Cennin Pedr yn ymddangos yn gyntaf? Beth am edrych drwy’r adroddiad llynedd a chymharu'r dyddiau blodeuo ar gyfer y Crocws a’r Cennin Pedr i'ch helpu penderfynu pa un fydd yn tyfu’n gyntaf?

Rwyf wedi atodi lluniau gan ysgolion a rhannwyd ar Twitter. Plîs rhannwch eich lluniau fel bydda’n gallu dangos nhw ar fy blog nesaf!

Daliwch ati Gyfeillion y Gwanwyn,

Athro'r Ardd

Eich sylwadau:

Ferryside V.C.P School: Mae wedi bod yn wythnos wlyb dros ben!

Ysgol Carreg Emlyn: Roedd yr ysgol ar gau Dydd Llun a Dydd Mawrth oherwydd yr eira.

Pembroke Primary School: We have planted tulips in pots also in school and it will be interesting to see how they compare to the daffodils and crocus. Professor Plant: That will be interesting, let me know how they compare Bulb Buddies!

Portpatrick Primary School: Shoots are stretching out of the ground :) . Professor Plant: What a lovely way of describing the sprouting of plants Bulb Buddies!

Inverkip Primary School: We really enjoyed doing it. We really want to do it again. Professor Plant: I’m glad to hear you are enjoying the project Bulb Buddies. Keep up the good work!

Newton Primary School: It's been a lovely week. It's been quite cold, but mainly dry. Four plants have started to grow over the weekend and by the end of the week they were around 2cm tall. Professor Plant: Gosh Bulb Buddies, thank you for keeping such a close eye on your plants. It will be interesting to see how much they grow week by week!

Darran Park Primary: There hasn't been any change to our bulbs this week.

Auchenlodment Primary School: We can see some roots growing out the bottom of the pots.

Ysgol San Sior: Our plants are growing well.

Darran Park Primary: We had a lot of snow on the weekend the temperature was very cold and below freezing on Monday and Tuesday. The temperature rose a little on Wednesday and it rained a lot.

Carnbroe Primary School: Hi Professor Plant last week we had snow,snow,snow! On Tuesday the rainfall cup was filled with snow because of the low temperature. On Friday we got sent home because of the red warning about a blizzard coming our way. Our bulbs look safe and are still sleeping. Professor Plant: Wow Bulb Buddies, it sounds as though you have had some extreme weather! Thank you for keeping me up dated.

St Julians Primary School: Melted snow increased our rainfall total on Monday. Our plants didn't seem to mind the colder weather!

Newton Primary School: A chilly week on the playground!

Beaufort Hill Primary School: Closed Monday and Tuesday due to snow.

St. Nicholas Primary School: We had a snow day on Monday - the 40mm (42mm) was ice in our rain gauge!

Hudson Road Primary School: It is getting colder and we have had heavy rain again

St Paul's CE Primary School: Frosty every morning, sunny spells.

Peterston super Ely Primary School: It was a wet week this week!

St Andrew's RC Primary School: We hope you have a merry Christmas and a happy new year. Professor Plant: Thank you Bulb Buddies, I hope you all enjoyed your holidays!

St Michael's CE (Aided) Primary School: There has been snow laying on our playground 11/12 December.

Canonbie Primary School: It's Christmas jumper day today so we were all wearing our Christmas jumpers as we were out measuring rainfall.

Helo Cyfeillion y Gwanwyn,

Heddiw yw’r diwrnod olaf i gasglu darlleniad tywydd cyn Nadolig! Byddwch yn cymryd darlleniad tywydd nesaf yr wythnos o’r 8-12 Ionawr. Wrth gofnodi eich darlleniadau i’r wefan, plîs nodwch ‘dim cofnod’ ar gyfer y dyddiau rydych i fwrdd o’r ysgol.

Does dim rhaid cymryd eich potiau adra dros y gwyliau. Os yw’r potiau mewn lle saf lle byddant ddim yn cael ei effeithio gan y gwynt, bydda nhw’n iawn. Mae'r pridd yn cadw’r bylbiau yn ddwfn yn erbyn y tywydd oer.

Mae’r tywydd wedi bod yn eithaf cynnes am y gaeaf, a bydd o’n ddiddorol i weld yr effaith mae hyn yn cael ar ein bylbiau! Gwelodd Tachwedd 2017 tymereddau ucha a llai o law na flwyddyn ddiwethaf. Ac er ein bod wedi cael ychydig llai o oriau haul na'r llynedd, oedd Tachwedd 2017 dal yr ail mwyaf heulog ers i gofnodion DU cychwyn yn 2012! Os mae’r patrwm yma yn parhau, efallai fyddwn yn weld ein blodau yn gynharach flwyddyn yma!

Mwynhewch eich gwyliau Cyfeillion y Gwanwyn.

Nadolig Llawen a Blwyddyn Newydd Dda,

Athro’r Ardd a Bwlb Bychan

Sylwadau:

Diolch ichi am eich holl sylwadau, cawsom grynodebau tywydd manwl iawn am yr wythnosau diwethaf, ac rydw i'n hynod o falch! Rydym hefyd wedi cael gwybod gan ychydig o ysgolion bod eu planhigion wedi dechrau blaguro! Byddwn yn ddiolchgar pe gallai'r ysgolion hyn rannu lluniau gyda mi cyn ac ar ôl y gwyliau Nadolig, fel y gallwn ni i gyd weld faint maent yn tyfu yn yr amser hwn!

Diolch am eich holl waith caled Cyfeillion y Gwanwyn. Edrychaf ymlaen at barhau eto yn y Flwyddyn Newydd!

Athro'r Ardd

Planhigion wedi dechrau blaguro:

Ysgol Beulah: Mae pedwar blaguryn wedi dechrau tyfu.

Ysgol San Sior: Our crocus plants have already started to grow! We are very excited – A.

Ysgol San Sior: A lot of our plants have started to grow but I am still waiting for mine. I'm checking every morning. – C.

Adamsdown Primary: My plant has started to grow.

St Julians Primary School: Lots of our daffodils have started to peek through the compost now.

Hemlington Hall Academy: Some of our crocuses have begun to grow. We can see them peeking through the top of the soil about 1-2cm. We didn't expect to see this until the spring.

Sylwadau am y prosiect:

Ysgol Gymraeg Dewi Sant (Llanelli): Nadolig Llawen a Blwyddyn Newydd Dda oddi wrth Blwyddyn 4 Ysgol Gymraeg Dewi Sant, Llanelli.

St Andrew's RC Primary School: It was really enjoyable to go outside to measure the status of the plants and to plant them.

YGG Tonyrefail: Having fun

Our Lady of Peace Primary School: First day of doing this in December can't wait for Christmas see you then.

Ysgol San Sior: We have asked a school in Barcelona to join us in this project. They have planted some bulbs that we bought and sent them. Their plants haven't grown like most of ours. Carys and Amelia are still checking every day for some growth. Professor Plant: That’s fantastic Bulb Buddies! Please keep me updated on how your projects go and what you learn.

Falkland Primary School: Plants are epic

Falkland Primary School: Cool stuff.

Sylwadau am dywydd eithafol:

Ysbyty Ifan: Dim ysgol dydd llun oherwydd eira dydd mawrth roedd 110 mm o eira yn y mesurydd glaw diolch am y cerdyn

Garstang St. Thomas' CE Primary School: We had local flooding this week!

Auchenlodment Primary School: Storm Caroline brought high winds this week to Johnstone.

Beaufort Hill Primary School: School closed on Friday due to snow

St Teresa's Primary School: The school was closed on Monday due to snow/ ice.

Ysgol Bro Pedr: 2 days off this week due to the snow

Henllys CIW Primary: the school was closed on monday and tuesday and on wednesday it was 43 mm

Shirenewton Primary School: Snow day Monday

Crynodebau tywydd:

Ferryside V.C.P School: Roedd wythnos hyn yn oer a cael lot o glaw.

Ysgol Casmael: Cesair ac eira wythnos yma.

Ysgol Carreg Emlyn: Roedd yr ysgol ar gau dydd gwener oherwydd yr eira felly nid oedd yn bosib cofnodi'r tywydd.

Ysgol Y Traeth: Wedi bwrw cenllysg ac eira ychydig heddiw (Dydd Gwener 8/12/17)

Ysbyty Ifan: mae hi wedi bod yn bwrw eira heddiw

Darran Park Primary: It’s the same as last week the lower the temperature the less rain and the higher the temperature the more rain.

Auchenlodment Primary School: It was a cold and dry week. We were off on Thursday as it was St Andrew's Day (Scotland's patron saint).

Carnbroe Primary School: Hi Professor Plant, we have had mixed weather this week. It was really wet on Monday, on Wednesday it was icy and today it was mild. Our plants are doing fine.

Carnforth North Road Primary School: We had some very cold weather.

Ysgol Iau Hen Golwyn: not much rain.

Stanford in the Vale Primary School: It's been a cold and frosty week!

St Paul's CE Primary School: Lots of heavy snow this week and very low temperatures. Snow lying thick on the ground Thursday and Friday. Frosty every morning.

Inverkip Primary School: It was frosty throughout the week. This will not help. There was barely any rain.

Waddingham Primary School: Overnight on Thursday, it snowed. By the time we did our readings on Friday, the snow had melted and the water level was 2mm.

Canonbie Primary School: We have had a slight flurry of snowflakes. We have not had much rain. It is quite cold.

Ysgol Bro Pedr: Beautiful and chilly end to a week that started miserably.

Stanford in the Vale Primary School: Hi been a cold and windy week, very cold and wet. Not excited for the winter coldness ahead. BYE BYE.

Beaufort Hill Primary School: Very cold week!

Garstang St. Thomas' CE Primary School: Brrrrrr!

Peterston super Ely Primary School: It was very cold this week for our bulbs!

St Robert's R.C Primary School: We didn't get much snow!

Inverkip Primary School: On Wednesday, we had lots of rain. This would help the plants grow. But because the temperatures were low, they might not grow.

Arkholme CE Primary School: This week was fairly cold and wet. In the mornings it was very frosty. We could not get to bulbs because of the plumbers. The temperatures were all above minus because we checked them in the afternoon and by then it was warmer.

St Robert's R.C Primary School: It got cold this week and we had a little bit of snow in Bridgend, but not much!

St Paul's CE Primary School: Heavy rain Thursday Friday. Cold all week. Frosty mornings

Pembroke Primary School: Would you like more detailed information as provided previously? I can include daily high, low and weekend information. Professor Plant: Hi Bulb Buddies, if you have time to enter the detailed information that would be lovely! And if you are doing any activities in the classroom using this data I’d love to hear about it!

Bardney Church of England & Methodist Primary: Cold!

Henllys CIW Primary: actual rain fall on Thursday was 25ml and friday raingage had fallen over with the snow

Portpatrick Primary School: Snow on Friday!

Canonbie Primary School: It has been a cold wind and we might be getting some snow. We have had a busy with our Christmas play.

Carnbroe Primary School: Hi Professor Plant the weather has been very cold this week. It started quite mild and damp and then on Thursday it dropped to 4°C. On friday it dropped again down to 2°C and it is very cold and icy but our plants are still thriving.

Darran Park Primary: Its kind of done the opposite to last week. The temperature has been higher and on Thursday we had more rain. Today we had some snow and the temperature has dropped.

Ysgol Iau Hen Golwyn: There was not that much rain this week and the temperature was high on the first 4 days and then on the last day it was 4 which is low.

Ysgol Bro Pedr: Rather chilly in the west of Wales!!!

Stanford in the Vale Primary School: We've had snow flurries this morning - it's been a cold week.

Llanishen Fach Primary School: It has been really cold this week. We have checked our bulbs but they haven't grown yet.

Carnforth North Road Primary School: Its been very cold this week.

Carnbroe Primary School: Hi Professor Plant we hope that you have been wrapped up this week. It has been very cold and icy in Carnbroe this week. It rained on Wednesday and today and because it has been so cold its iced over. Our plants are still sleeping. Professor Plant: I have been wrapped up, thank you Bulb Buddies. And thank you for sharing your lovely photos.

Edenham Church of England Primary School: Monday - snowfall not rainfall!!! Professor Plant: Exciting Bulb Buddies, I hope you enjoyed bringing the snow in to melt before taking your readings! Keep up the good work.

YGG Tonyrefail: On Monday Tuesday and Wednesday it was snowing so no record

Ysgol Iau Hen Golwyn: The temperature and rainfall have both been very low as there was not much rain and not very hot.

Helo Cyfeillion y Gwanwyn,

Diolch am rannu eich sylwadau gyda'r data tywydd wythnos dwytha. Rwyf wedi atodi rhai yn isod. Mae llawer ohonoch yn ddweud bod y tywydd wedi oeri a bod 'na mwy o law. Mae rhai ohonoch chi hyd yn oed wedi cael eira! Dyma pam dwi am esbonio sut mae meteorolegwyr (gwyddonwyr tywydd) yn mesur eira. 

Mae mesur faint o law sy’n disgyn yn hawdd o’i gymharu â mesur faint o eira sy’n disgyn. Fydd eira ddim yn bihafio! Bydd yn aml yn cael ei chwythu gan y gwynt ac yn lluwchio, sy’n golygu bod yr eira’n ddwfn mewn mannau ond yn llawer llai dafliad carreg i ffwrdd. Oherwydd bod yr eira’n disgyn yn anghyson, bydd y mesuriadau o’r llefydd yma’n anghywir! Dyna pam mae’n rhaid mesur mewn mannau gwastad, agored ymhell o ble fydd eira’n lluwchio. Bydd eira hefyd yn chwarae gemau gyda’r Meteorolegwyr sy’n ceisio ei fesur – bydd yn toddi’n ddŵr, cyn rhewi fel iâ. Felly dyw’r eira sy’n cael ei fesur ddim bob tro yn cyfateb i faint o eira sydd wedi disgyn. Mae eira newydd yn disgyn ar ben hen eira hefyd, ac mae’n anodd dweud faint o eira sydd wedi disgyn o un diwrnod i’r llall. 

Mae’n rhaid i’r meteorolegwyr gofio holl driciau’r eira a meddwl am ffyrdd i ddarganfod faint o eira sydd wedi disgyn. Byddan nhw’n edrych ar gwymp eira (faint o eira sy’n disgyn mewn diwrnod) a dyfnder eira (cyfanswm dyfnder yr eira, hen a newydd). Un ffordd o fesur cwymp eira yw gyda ffon bren. Bydd y meteorolegwr yn gosod y pren mewn lleoliad agored lle na fydd eira’n lluwchio ac yn mesur yr eira bob chwech awr. Drwy glirio’r eira o’r pren ar ôl ei fesur, dim ond eira’r diwrnod hwnnw fydd yn cael ei fesur, a gall y gwyddonydd ddweud faint o eira sydd wedi cwympo ar y diwrnod hwnnw. 

Gallwn ni hefyd fesur eira wedi toddi ar ffurf dŵr. Gallwch chi felly ddefnyddio’ch mesurydd glaw i fesur cwymp eira. Os taw dim ond ychydig o eira sy’n cwympo, bydd yn toddi yn y mesurydd beth bynnag, ond os yw hi’n bwrw’n drwm, ewch â’r mesurydd i mewn ac aros iddo doddi’n ddŵr. Gallwch chi wedyn fesur y dŵr fel rydych chi wedi’i wneud bob wythnos, a’i gofnodi fel glawiad yn eich cofnodion tywydd. 

Os oes eira ar lawr a bod digon o amser i arbrofi, beth am fynd ati i fesur dyfnder yr eira? Y cyfan sydd ei angen arnoch chi yw pren mesur (neu pren eira os ydych chi am siarad fel gwyddonydd gwych!). Gwthiwch y pren i’r eira tan ei fod yn cyffwrdd y ddaear a chofnodi pa mor ddwfn yw’r ddaear fesul milimedr. Rhaid i chi fesur o arwyneb gwastad (fel mainc) mewn lle agored lle nad yw’r eira’n lluwchio. Rhaid i chi gofnodi o leiaf tri mesuriad i gyfrifo dyfnder cyfartalog yr eira lleol. Cyfrifwch y cyfartaledd drwy adio’r cofnodion gwahanol a’u rhannu gyda’r nifer o gofnodion. Os ydw i’n cofnodi tri dyfnder o 7cm, 9cm a 6cm, rhaid i fi adio pob rhif (7 + 9 + 6 = 22) cyn rhannu gyda 3 (22 / 3 = 7.33). Dyfnder cyfartalog yr eira felly yw 7.33cm. 

Mae gorsafoedd tywydd fel y Swyddfa Dywydd (MET Office) wedi troi at dechnoleg i ddyfeisio dulliau newydd o fesur dyfnder eira. Edrychwch ar y llun o un o orsafoedd eira’r Swyddfa Dywydd. Mae nhw’n defnyddio synwyryddion laser i fesur dyfnder yr eira ar yr arwyneb gwastad. Gall meteorolegwyr gasglu data o bob cwr o’r wlad wrth wasgu botwm – llawer haws a mwy dibynadwy nag anfon pobl allan i’r oerfel gyda phren eira! Mae pob un o orsafoedd eira’r Swyddfa Dywydd i’w gweld ar y map – oes un yn agos atoch chi? 

Os yw hi wedi bwrw eira, cofiwch fesur y cwymp gyda’r mesurydd glaw neu’r dyfnder gyda phren eira a nodi’r canlyniadau fel ‘Sylwadau’ wrth uwchlwytho eich cofnodion wythnosol. Bydd yn ddiddorol cymharu dyfnder yr eira â chwymp yr eira yn y mesurydd glaw! 

Daliwch ati Gyfeillion y Gwanwyn, 

Athro’r Ardd

Eich sylwadau o wythnos tri:

Ysgol Y Traeth: Wedi bwrw glaw llawer ac wedi bod yn wyntog ofnadwy.

Athro’r Ardd: Diolch am rannu eich sylwadau tywydd Cyfeillion.

Ysgol Beulah: Mae'n llawer oerach heddiw na oedd e llawer mwy or wythnos.

Athro’r Ardd: Helo, dywedodd ysgolion eraill mai dydd Gwener oedd eu diwrnod oeraf nhw hefyd. Diolch am rannu eich sylwadau tywydd.

Ellel St John's CE Primary School: We had record amounts of rainfall on Wednesday 22nd November that resulted in major flooding. Our village (Galgate) was on the local and national news.

Athro’r Ardd:  I’m sorry to hear you’ve had such bad flooding Bulb Buddies! I did hear about this on the news, and other schools have commented to say that they were affected too. Thank you for informing me of how extreme the weather has been in your area.

Arkholme CE Primary School: This week it has flooded the garden and also the playground. As you can see, there has been quite a lot of rainfall and it has been quite chilly. Lancaster had the most rainfall recorded in one day ever.

Athro’r Ardd: Hi Bulb Buddies, I heard about flooding in your area on the news. I hope the school grounds have drained now and that you are able to play outside again. Keep me updated!

Henllys CIW Primary: On Wednesday actual rainfall 22mm.

Athro’r Ardd: Thank you for the detailed weather report Bulb Buddies.

Canonbie Primary School: It has been a busy week as in rehearsal mode for our school show. It has rained more this week. It has been icy and cold.

Athro’r Ardd:  Your comment is very Christmassy! I hope your school show goes well Bulb Buddies.

Auchenlodment Primary School: There was torrential rain on Monday night and we even had snow on Friday. It's beginning to look like Christmas!

Athro’r Ardd: I hope you enjoyed the snow Bulb Buddies.

Carnbroe Primary School: We were off on Monday. We have had lots of different weather this week. It has been very wet, frosty and on Friday it snowed. We checked our plants and although they were a bit wet they were still fine.

Athro’r Ardd: Your bulbs are very hardy and will be fine with some cold weather. Well done for checking on them, and thank you for sharing your observations of the week’s weather!

YGG Tonyrefail: Wet week professor plant!!

Athro’r Ardd: Your rain fall readings testify to that as well Bulb Buddies. Keep up the good work.

Ysgol Bro Pedr: Very wet week.

Athro’r Ardd: You’re not the only ones to report an increase in rain fall Ysgol Bro Pedr, I’m interested to see if this continues into next week!

Inverkip Primary School: Will our plants grow well with this temperature and rainfall? We think our plants will grow well because they are getting used to a new temperature and are not getting too much rainfall.

Athro’r Ardd: Hi Bulb Buddies, your plants are very sturdy and are nice and snug in the earth. Your temperature and rainfall from this week will be perfect for them, it’s only extreme weather conditions that would prove difficult for them!

St Paul's CE Primary School: Rainy and windy days, with heavy rain 23.11.17 overnight (22.11.17). Frosty on each of the mornings.

Athro’r Ardd:  Thank you for your weather observations Bulb Buddies. I can see that your readings show a much wetter week than in week two.

Peterston super Ely Primary School: The children were amazed by Tuesday's rainfall result!

Athro’r Ardd: That is quite a high reading! I’m glad they are enjoying the project.

Bacup Thorn Primary School: The weather is really cold this week. Friday has been the coldest. We might get snow this weekend.

Athro’r Ardd: Hi Bacup ThornPrimary, gosh it has been a cold week for you. I hope you are wrapping up warm to take your weather readings!

Ysgol Casmael: First frost today

Athro’r Ardd: Do you think you will have snow before Christmas Bulb Buddies?

Ysgol Iau Hen Golwyn: There has not been a lot of rain this week and the temperature has been going down each day and then on the last day it went up one as well.

Athro’r Ardd: Hi Bulb Buddies, it sounds as though you got of lightly in terms of rainfall compared to a lot of other schools! Thank you for your weather observations.

Darran Park Primary: We have had lots of rain with quite high temperatures except for Friday where the temperature was a lot colder with no rain

Athro’r Ardd:  Thank you for your observations Bulb Buddies.