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Let's talk Winter!


Steve

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Warning issued for most of I-70 and north for 5-8".

 

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE WILMINGTON OH

303 PM EST FRI FEB 20 2015

INZ050-058-059-OHZ042-045-046-051>056-060>062-210415-

/O.UPG.KILN.WW.Y.0011.150221T0300Z-150222T0500Z/

/O.EXB.KILN.WS.W.0004.150221T0300Z-150222T0000Z/

WAYNE-FAYETTE IN-UNION IN-DARKE-UNION OH-DELAWARE-MIAMI-CHAMPAIGN-

CLARK-MADISON-FRANKLIN OH-LICKING-PREBLE-MONTGOMERY-GREENE-

INCLUDING THE CITIES OF...RICHMOND...CONNERSVILLE...LIBERTY...

GREENVILLE...MARYSVILLE...DELAWARE...PIQUA...URBANA...

SPRINGFIELD...LONDON...COLUMBUS...NEWARK...EATON...DAYTON...XENIA

303 PM EST FRI FEB 20 2015

...WINTER STORM WARNING IN EFFECT FROM 10 PM THIS EVENING TO 7 PM

EST SATURDAY...

THE NATIONAL WEATHER SERVICE IN WILMINGTON HAS ISSUED A WINTER

STORM WARNING FOR SNOW...SLEET...AND FREEZING RAIN WHICH IS IN

EFFECT FROM 10 PM THIS EVENING TO 7 PM EST SATURDAY. THE WINTER

WEATHER ADVISORY IS NO LONGER IN EFFECT.

* ACCUMULATIONS...SNOW AND SLEET ACCUMULATION OF 5 TO 8

  INCHES...ALONG WITH LIGHT ICE ACCUMULATIONS.

* TIMING...SNOW WILL DEVELOP ACROSS THE AREA LATE TONIGHT AND

  CONTINUE INTO SATURDAY MORNING. THE SNOW WILL BE HEAVY AT TIMES.

  THE SNOW WILL MIX WITH SLEET OR FREEZING RAIN SATURDAY MORNING.

  BY SATURDAY AFTERNOON...TEMPERATURES SHOULD EVENTUALLY WARM UP

  ENOUGH FOR RAIN OR A RAIN AND SNOW MIX. PRECIPITATION WILL

  QUICKLY END FORM WEST TO EAST SATURDAY EVENING.

 

So they still believe it will change to rain tomorrow afternoon, but maybe not before a good thump.

 

This is  great...anything over 4 would be great!! What is everybody's take on this if we have no mixing at all..is 6-10 doable?

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I drew this up between classes earlier. After glancing at the 18z NAM figured I may as well post it now instead of sitting on it for another 4 hours, because I doubt I'll be fully confident in that 6-10" area until 5" falls and it's still ripping :lol:

 

post-525-0-63470800-1424466518_thumb.png

 

Outstanding jet support at 250mb and strong low to mid-level warm air advection will cause snow across much of the state late tonight through Saturday evening. GFS/Euro/NAM 12z runs agree on bringing 0.5" of QPF up to near the route 30 corridor as all snow. An examination of the low to mid-level jet and corresponding lift both suggest a potential period of heavy snow Saturday morning up to route 30, so could see some 6" amounts close to route 30. Even as far north as Cleveland, looks like a good shot of moderate snows on low to mid-level WAA late tomorrow morning into the afternoon with good upper jet support so think a few inches of wet snow is likely. Farther south, NAM forecast soundings as well as the nose of strong mid-level WAA underneath the aforementioned jet  support suggest a fairly long period of moderate to heavy precip as you approach I-70 and definitely south of I-70. Good agreement on at least 0.6-0.8" of QPF in Columbus and over 1" QPF over southern Ohio. NAM QPF of almost 2" south of US 50 is too high, but over 1" seems extremely reasonable given prolonged jet support and very strong lift on low to mid-level WAA.

 

Question becomes where mixing cuts into the snow and how much snow can fall before this occurs. Air parcel trajectories on the 12z NAM in the 900-850mb level brought parcels to southern OH by mid to late tomorrow afternoon that are above freezing, although dynamical cooling can cool things a few degrees, which most hi-res models show. Surface parcels arriving in Athens at 21z Saturday come from southern TN at 15z today where it was in the 20's with snow pack in between, so surface temps may actually be a little cooler than modeled and stay below freezing or right at freezing north of the Ohio River. Am expecting the vast majority of precip to fall as snow along I-70 and even down to Cincy and Athens, I believe dynamical cooling will keep precip snow during a large chunk of the storm. All areas could change to drizzle or freezing drizzle for a time Saturday evening as deep moisture pulls out aloft but low levels remain moist. Went for lower amounts in far southern Ohio as most models appear too warm in the southern tip of the state for dynamical cooling to completely overcoming the WAA and keep things snow. In the heavier snow zone, may see a setup where heavier precip falls as snow and lighter precip falls as a mix...cutting down on totals a little but creating a mess.

 

Ran 12z GFS output through BUFKIT with a 9:1 ratio northern OH sites, 8:1 ratio central OH sites and 7:1 ratio southern OH sites. Still got over 3" of snow for CLE, 4-5" for CAK, over 4" for CMH, and over 7" in the heavier swath from CVG to PKB. Given the GFS is warmer and lower on QPF than most other models, and these amounts are in the ranges on the map, feel that there is a good chance at most areas hitting the range on the map. NAM output is much more impressive, so areas that do stay all snow in southern OH will possibly exceed 10" in isolated spots given the duration of heavy snows down there and the amount of moisture involved. Actually feel this map is somewhat conservative in spots all things considered.

 

I feel very comfortable with this forecast north of a Wilmington to Cambridge line. Farther south is more questionable as there is boom or bust potential if there is less or more mixing, especially considering the QPF some models are spitting out down there. Come at me now!

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And the LMK AFD--- interesting couple of notes--- they are still unsure of the set up....and really lack confidence in how far north the warm air can surge....which tells me that despite the model depictions, there is uncertainty (in their minds) that they are fully factoring in the current conditions from the preceding air mass.

 

This will be fun, fun, fun to watch.

 

http://forecast.weather.gov/product.php?site=LMK&issuedby=LMK&product=AFD&format=CI&version=1&glossary=1

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I have to ask you guys, because I don't know if it was a malfunction, but did Ashtabula really drop to -29 overnight. That is insane if true, and was wondering why they ended up almost 10 degrees colder than any of the other reporting stations near them?

 

according to an article on wxbell that was legit, but I'm skeptical

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Nice write up ohweather!

Thank you! If it verifies, it'll be a fun day tomorrow!

 

according to an article on wxbell that was legit, but I'm skeptical

A few personal weather stations dropped to -30 or colder in rural NE Ohio, so I think the -29 is legit and believe that some spots got below -30. Surrounding counties had "unofficial" thermometers clock values of -25 or colder...my house got to -24 if you believe a car thermometer, and I'm not really out in the sticks up there. Ashtabula County is one of the most rural in that corner of the state, especially once you get south of I-90, and the whole county is essentially a bowl (except for the western and eastern fringes), so it can get cold. There were lake effect clouds into Cleveland for half of the night but not in Ashtabula, which may explain why areas west and south weren't quite as cold. Ashtabula County also has some of the deepest snow pack in the state.

 

 

great write up OHweather

Thanks!

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I feel very comfortable with this forecast north of a Wilmington to Cambridge line. Farther south is more questionable as there is boom or bust potential if there is less or more mixing, especially considering the QPF some models are spitting out down there. Come at me now!

Bout time we see a good analysis from you. You're all we have. You and Mike lol. Anyways similar to my updated map.post-1236-0-56853500-1424468262_thumb.pn

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This could be our "big one" for the winter, I couldn't NOT post! :P

Nice breakdown there btw! I'm definitely excited for what may happen here tomorrow.

I do alright on the maps lol. I couldn't write an analysis like yours though. But my followers wouldn't understand it anyways lol. But I just am not convinced in the huge southern totals. Find it hard to believe mixing isn't an issue so went 4-6

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