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November 2014 Obs and Disco


Bob Chill

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Just got pelted with sleet walking to car in Bel Air. Car temp says 58. What the heck?!?!

 

I did not see this coming. From NWS Mount Holly's updated AFD:

 

WE ARE ADDING POPS SOUTHWEST IN RESPONSE TO MID

LEVEL MOISTURE AND A RELATIVELY UNSTABLE LAPSE RATE ABOVE 700MB.

EVEN ISOLATED THUNDER AND SMALL HAIL HAS OCCURRED IN THE LOWER

SUSQUEHANNA VALLEY. LATEST HRRR WAS USED AS AN AREAL AND TIMING

TREND. THE PREDICTED ECHO INTENSITY AND MID LEVEL LAPSE RATE WAS

LOWER OVER OUR CWA, SO OPTED FOR PLAIN SHOWERS FOR NOW.

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My prediction from last night, then in parentheses observed temps this morning:

 

BWI: 32F (37F)

IAD: 29F (35F)

DCA:40F (44F)

RIC: 32F (32F)

 

IMBY...

 

Inland: 29F (31.5F)

Water: 35F (41F)

 

I give myself an A+

 

I'm in Wisconsin, but Wxbug showed a friggin' 40F low this morning back home.  40F?  WTF happened to the freeze watch?  Richmond was 32F and we were 40?  Jeezus, that's pathetic.

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idk about that

dp in York, PA, very close to Mapgirl, was in the mid teens, so evaporational cooling aloft could have produced some sleet imho

http://w1.weather.gov/data/obhistory/KTHV.html

Hmm not sure on that. When 700 mb to the surface is above freezing, and from the surface up to about 5000 ft is 10 C or higher, cant see how you get sleet. Most places were reporting surface temps in the mid 50s at that time.  I have never seen sleet with surface temps higher than the low to mid 40s, and even then temps would have to cool rapidly with height for it to occur.

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Hmm not sure on that. When 700 mb to the surface is above freezing, and from the surface up to about 5000 ft is 10 C or higher, cant see how you get sleet. Most places were reporting surface temps in the mid 50s at that time. I have never seen sleet with surface temps higher than the low to mid 40s, and even then temps would have to cool rapidly with height for it to occur.

Trust me, I know. Very unlikely that it happened, but...it happened. Perhaps it was hail, very small hail. Whatever, either way, something in the form of ice fell at my house last night. Hail, sleet, oh well.

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Trust me, I know. Very unlikely that it happened, but...it happened. Perhaps it was hail, very small hail. Whatever, either way, something in the form of ice fell at my house last night. Hail, sleet, oh well.

Oh I dont doubt that it happened. I saw the obs. There were also reports of thunder, and the steep lapse rates aloft along with the very mild low/mid level temps all point to hail. For sleet to occur there has to be a deep layer of cold with a shallow warm layer above that, and of course below freezing upward from there where snow would form. There was some really dry air at low levels as Mitch mentioned, which was clear on the sounding, but I dont know if evap cooling would do the trick, and given all the other data being supportive of hail, it likely was hail you experienced.

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Inversion.  It is in the 60s currently in some of the places above 1000ft.  Also, I consider IAD to be worse than DCA on low temps.

 

attachicon.gif2014110412.72403.skewt.parc.gif

 

Wow.  That is some inversion.  Thanks for the explanation.  I'm still bitter though.... and I'm not even there.  It's even warm up here in Wisconsin.  Warm air just seems to follow me.

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Airmass that the 13km GFS brings in next week would verbatim break the record low max temp and record low temp for IAD next Wednesday and maybe also record low max at BWI (both airports' records are 41F for November 12th) with screaming winds.  

 

It drops a 1050 mb (!!!) high down into the Plains with a deep upper low (perler vertex) passing through the Lakes.  

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Airmass that the 13km GFS brings in next week would verbatim break the record low max temp and record low temp for IAD next Wednesday and maybe also record low max at BWI (both airports' records are 41F for November 12th) with screaming winds.  

 

It drops a 1050 mb (!!!) high down into the Plains with a deep upper low (perler vertex) passing through the Lakes.  

 

That would be some nice cold and would be great to see #polarvertex back again on Twitterverse

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