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Jan 25/26 Storm Threat...(Part 3)


Marion_NC_WX

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Per HPC...Pretty much sums up our day here on the board...:popcorn:

VALID 12Z TUE JAN 25 2011 - 12Z SAT JAN 29 2011

12Z MODEL UPDATE... ALONG THE EAST COAST... THE GFS APPEARS TO

HAVE JOINED THE BANDWAGON OF THE OTHER 00Z GUIDANCE THROUGH ABOUT

00Z/WED WITH THE EMPHASIS ON THE SOUTHERN ENERGY THROUGH THE GULF

STATES. IT THEN TAKES THE LOW ON THE EASTERN SIDE OF THE GUIDANCE

SPREAD WELL OUTSIDE THE BENCHMARK BEFORE REJOINING THE CONSENSUS

NEAR NOVA SCOTIA. THE 12Z CANADIAN CONTINUES ITS WESTERN TRACK

FROM WESTERN NC THROUGH DC THEN TO THE GULF OF MAINE BY 12Z/THU.

12Z UKMET SHIFTED ITS TRACK A BIT TO THE WEST OF ITS 00Z RUN AND

IS SLOWER AS WELL. 12Z GEFS MEAN SLOWED DOWN AS WELL AND MOVED

BACK TOWARD THE COAST BUT IS STILL QUICKER THAN THE 00Z ECMWF

ENSEMBLE MEAN. 12Z ECMWF CONTINUES ITS WOBBLE EAST OF EARLIER RUNS

AND NOW TAKES THE LOW VERY NEAR THE BENCHMARK BY 00Z/THU. AS HAS

BEEN THE CASE THIS WINTER... THESE COASTAL SYSTEMS HAVE BEEN

ANYTHING BUT EASY TO FORECAST. EARLIER FORECAST WAS WELL WITHIN

THE SPREAD SO NO CHANGES WERE MADE IN THE FINAL ISSUANCE. SYSTEM

DROPPING OUT OF CANADA LATE NEXT WEEK SHOWS GOOD 12Z GEFS MEAN

AGREEMENT WITH THE 00Z ECMWF ENSEMBLE MEAN SO WILL LEAVE WELL

ENOUGH ALONE THERE AS WELL...

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Yep. And the main part, imo, is in bold below... indeed :popcorn:and maybe :drunk:

Per HPC...Pretty much sums up our day here on the board...:popcorn:

VALID 12Z TUE JAN 25 2011 - 12Z SAT JAN 29 2011

THESE COASTAL SYSTEMS HAVE BEEN

ANYTHING BUT EASY TO FORECAST. EARLIER FORECAST WAS WELL WITHIN

THE SPREAD SO NO CHANGES WERE MADE IN THE FINAL ISSUANCE. SYSTEM

DROPPING OUT OF CANADA LATE NEXT WEEK SHOWS GOOD 12Z GEFS MEAN

AGREEMENT WITH THE 00Z ECMWF ENSEMBLE MEAN SO WILL LEAVE WELL

ENOUGH ALONE THERE AS WELL...

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Since you are putting this out, maybe you should comment on areas effected by these trends. Or are you speaking of the eastern 2/3 of NC?

Thanks man!!!

Model Track Trend* -NAO 50/50 Low Cold Air Feed

Euro Coastal East NO NO NO

Ukie Inland West NO NO NO

GFS Coastal Storm from no storm NO NO NO

GGEM Inland West NO NO NO

Nogaps Inland West NO NO NO

* Trends given from 0Z to 12Z

Good luck, everyone!

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KGSP has spoken in Afternoon AFD:

OVERALL...CONFIDENCE IN HEAVY SNOW ACROSS THE MTNS AND THE IMMEDIATE

FOOTHILLS CONTINUES TO INCREASE. THE EASTWARD EXTENT OF THE RAIN

SNOW LINE...HOWEVER...IS STILL IN QUESTION. I/VE WARMED THINGS UP A

LITTLE...WHICH CUTS SNOW TOTALS BACK TO A COUPLE INCHES ALONG A LINE

FROM GREENVILLE TO STATESVILLE...WITH MAINLY RAIN DOWN TOWARD

CHARLOTTE. IF THE WARMER NAM/UKMET VERIFY...THIS WILL WORK OUT

FAIRLY WELL. IF THE COOLER ECMWF WORKS OUT...THE HEAVY SNOW WOULD

FALL FURTHER EAST.

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For Cheez......above 50% hahaha

FFC update my zone forecast for Dalton,GA

Monday Night: A chance of rain and snow, mainly after 1am. Cloudy, with a low around 36. Chance of precipitation is 30%.

Tuesday: Rain and snow likely. Cloudy, with a high near 41. Chance of precipitation is 60%.

Tuesday Night: A chance of snow. Cloudy, with a low around 29. Chance of precipitation is 50%.

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Since you are putting this out, maybe you should comment on areas effected by these trends. Or are you speaking of the eastern 2/3 of NC?

Thanks man!!!

It's hard to say. The Euro and GFS are the only coastals, so if anyone does, western 1/3 of NC back to the SW in to SC and N. GA and E. TN have the best shot at good snow. Everything east of there is junk, if it's not entirely wet. The inland models take the good snows even farther west. The water's too muddy with this whole thing. It's not clean at all. But because there's no good cold air source feeding the storm and because there's no blocking, I give the inland tracks more merit. Even if the coastal verifies, the thing is really going to need to bomb quickly to make it more clear cut snow, even for a lot of the western areas. Not saying no snow for them, but it's just not clear cut. Relying on dynamic cooling makes for a very murky forecast with high bust potential.

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and this means what ?

The formatting got jumbled when I posted. It looked much neater in the big white box before I hit the Post button. Anyway, it's just showing the trends from the 0Z to 12Z runs of those models, so we can all see which way the track shifted over a 12 hr model run cycle. Some of the shifts, like the Ukie, were quite substantial, while the Euro slipped east much less dramatically. Bottom line is, don't ride any model to the finish line yet.

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Good call! From where we are right now...

KGSP has spoken in Afternoon AFD:

OVERALL...CONFIDENCE IN HEAVY SNOW ACROSS THE MTNS AND THE IMMEDIATE

FOOTHILLS CONTINUES TO INCREASE. THE EASTWARD EXTENT OF THE RAIN

SNOW LINE...HOWEVER...IS STILL IN QUESTION. I/VE WARMED THINGS UP A

LITTLE...WHICH CUTS SNOW TOTALS BACK TO A COUPLE INCHES ALONG A LINE

FROM GREENVILLE TO STATESVILLE...WITH MAINLY RAIN DOWN TOWARD

CHARLOTTE. IF THE WARMER NAM/UKMET VERIFY...THIS WILL WORK OUT

FAIRLY WELL. IF THE COOLER ECMWF WORKS OUT...THE HEAVY SNOW WOULD

FALL FURTHER EAST.

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Thanks! and I agree on the bold statement below!

Got to be in the right place at the right time..

It's hard to say. The Euro and GFS are the only coastals, so if anyone does, western 1/3 of NC back to the SW in to SC and N. GA and E. TN have the best shot at good snow. Everything east of there is junk, if it's not entirely wet. The inland models take the good snows even farther west. The water's too muddy with this whole thing. It's not clean at all. But because there's no good cold air source feeding the storm and because there's no blocking, I give the inland tracks more merit. Even if the coastal verifies, the thing is really going to need to bomb quickly to make it more clear cut snow, even for a lot of the western areas. Not saying no snow for them, but it's just not clear cut. Relying on dynamic cooling makes for a very murky forecast with high bust potential.

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After looking at the ECMWF soundings for RDU it looks like this

Though hour 90 6z Wed 0.4 inches of qpf has fallen and it looks to be all rain. Euro surface temps are in the upper 30s, the sounding is above freezing up to near 775mb, it is nearly isothermal though at around 1.5C or so from 900 too 775mb.

At hour 96, 12z Wed, it looks like an all snow sounding. Still almost saturated in the dendritic growth region, below freezing from say 950 up, Euro surface temps are around 36F. 0.56 inches of QPF fell between 6z-12z Wed, so I would imagine there is a change to snow sometime in between there. By 18z Wed hour 102, the precip has ended and it must end shortly after 12z with clearing and the model then shoots the temp up into the low 40s.

So taken literally, I would say of the 1.24 inches of QPF at RDU, the first 0.4 is definitely rain, the last 0.28 is likely snow, with the middle 0.56 rain changing to snow. SO there would likely be accumulating snow at RDU from this and possibly a few inches.

The 925mb temps are above 0 across all of the Carolinas and Georgia at hour 90 and essentially remain that way at hour 96 except for the northern/northeast piedmont where this is likely because of strong UVVx

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Yes, but NW I-40 takes out a great chunk of wnc. Thinking more the stated line that noted. Greenville to Statesville. More of a ra/sn mix s of 40 into the middle of southern foothills.

Let see were she goes :)

At this point, I agree with KGSP.

Heavy snow in mountains and NW of I-40.

Rain and fail again down in Charlotte southern NC area.

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After looking at the ECMWF soundings for RDU it looks like this

Though hour 90 6z Wed 0.4 inches of qpf has fallen and it looks to be all rain. Euro surface temps are in the upper 30s, the sounding is above freezing up to near 775mb, it is nearly isothermal though at around 1.5C or so from 900 too 775mb.

At hour 96, 12z Wed, it looks like an all snow sounding. Still almost saturated in the dendritic growth region, below freezing from say 950 up, Euro surface temps are around 36F. 0.56 inches of QPF fell between 6z-12z Wed, so I would imagine there is a change to snow sometime in between there. By 18z Wed hour 102, the precip has ended and it must end shortly after 12z with clearing and the model then shoots the temp up into the low 40s.

So taken literally, I would say of the 1.24 inches of QPF at RDU, the first 0.4 is definitely rain, the last 0.28 is likely snow, with the middle 0.56 rain changing to snow. SO there would likely be accumulating snow at RDU from this and possibly a few inches.

The 925mb temps are above 0 across all of the Carolinas and Georgia at hour 90 and essentially remain that way at hour 96 except for the northern/northeast piedmont where this is likely because of strong UVVx

Thanks Allan for the info!!

BTW, I've got the 18z nam out to 54 and so far it looks close the 12z run.

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This is going to be a messy wet snow for those that do get snow outside of the mountains, and will probably not stick to the roads at all unless we get some heavy rates or its at night. Im not too excited for this storm as far as accumualtions here in CLT. Even with this last storm, we were in the upper 20s the entire storm here in charlotte and the snow failed to really stick to most paved surfaces. Good luck with surface temps in th 31-33 range (and thats being generous given most model output). :yikes:

Obviously its not set in stone but I dont see how this changes enough to signifcantly affect anyone outside of the mountains/ north of I-40

Just some random thoughts...

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This is going to be a messy wet snow for those that do get snow outside of the mountains, and will probably not stick to the roads at all unless we get some heavy rates or its at night. Im not too excited for this storm as far as accumualtions here in CLT. Just with this last storm, we were in the upper 20s the entire storm here in charlotte and the snow failed to really stick to most paved surfaces. Good luck with surface temps in th 31-33 range (and thats being generous given most model output). :yikes:

Obviously its not set in stone but I dont see how this changes enough to signifcantly affect anyone outside of the mountains/ north of I-40

Just some random thoughts...

I disagree. Ground temps will be cold enough, combined with heavy rates which is key, that roads can become covered even with low 30s. Seen i5 happen too many times to not feel that way. Without heavy rates though, you are right, it would have a hard time accumulating on the roads. If it snows, will have a heavy wet snow however that will stick everything else I believe even if not the roads

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REA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE PEACHTREE CITY GA

335 PM EST SAT JAN 22 2011

.SHORT TERM /TONIGHT THROUGH MONDAY/...

NO WEATHER PROBLEMS EXPECTED THROUGH THE DAYTIME SUNDAY. THE GFS/NAM

ARE SIMILAR WITH FORECASTING A SHORT WAVE AND MOISTURE THAT WILL

AFFECT MAINLY N GA WITH LIGHT RAIN AND/OR SNOW SUNDAY NIGHT INTO

EARLY MONDAY. THE WAVE WILL BE RATHER FAST MOVING WITH ONLY 20-30

PERCENT POPS FOR MEASURABLE PRECIPITATION SUNDAY NIGHT WITH FLURRIES

POSSIBLE FOR THE NE MOUNTAINS EARLY MONDAY. THIS SYSTEM WILL NEED TO

BE MONITORED FOR POSSIBLE SMALL SNOW ACCUMUALATIONS.

UNCERTAINTY INCREASES THROUGH MONDAY NIGHT WITH A DIEING COLD FRONT

TO THE WEST AND GULF OF MEXICO LOW PRESSURE EXPECTED TO DEVELOP AND

MOVE TO S OF LA. MODELS SEEM CONSISTENT WITH SUGGESTING THE CHANCE

OF RAIN OR SNOW FOR FAR N GA MONDAY NIGHT. MONDAY NIGHT POPS ABOUT

30 PERCENT FOR N AND W GA.

FORECAST LOW TEMPERATURES RUNNING 5-10 DEGREES BELOW NORMAL TONIGHT

AND NEAR TO 10 DEGREES BELOW NORMAL SUNDAY NIGHT. FORECAST HIGH

TEMPERATURES 3-5 DEGREES BELOW NORMAL FOR SUNDAY AND MONDAY. MOS

NUMBERS SEEMED TOO WARM FOR THE MONDAY HIGH`S AND FAVORED THE

FORECAST HIGHS FROM THE PREVIOUS FORECAST PACKAGE.

.LONG TERM /TUESDAY THROUGH SATURDAY/...

MODELS DIFFER ENOUGH FOR TUESDAY THAT WILL SIGNIFICANTLY AFFECT THE

FORECAST. THE NAM TRACKS THE SURFACE LOW ACROSS CENTRAL GA AND THIS

TRACK WILL ALLOW FOR NEARLY ALL RAIN ACROSS N GA. THE GFS AND

EUROPEAN TRACK THE SURFACE LOW FARTHER S THAT SUGGESTS THAT RAIN OR

SNOW COULD DEVELOP OVER FAR N GA WITH THE POSSIBILITY FOR

ACCUMULATIONS IN THE 1-2 INCH RANGE BY DAYS END TUESDAY. THE PASSING

SURFACE LOW AND UPPER SYSTEM BRINGS MORE COLD AIR IN QUICKLY TUESDAY

NIGHT FAVORING A CHANGE OVER OR CONTINUATION OF SNOW CHANCES FOR N

GA AND A POSSIBLE RAIN/SNOW MIX FOR PARTS OF CENTRAL GA. THIS TIME

FRAME WILL ALSO NEED TO BE MONITORED FOR ACCUMULATIONS.

GFS/EUROPEAN SIMILAR WITH ENDING PRECIP CHANCES FOR WEDNESDAY AND

KEEPING THINGS MAINLY DRY THROUGH SATURDAY. HOWEVER BOTH MODELS ARE

INDICATING AN UPPER TROUGH PASSING BY LATE WEDNESDAY/EARLY THURSDAY

AND AGAIN ON FRIDAY WITH MINIMAL MOISTURE ASSOCIATED. BOTH MODELS

BRING WHAT APPEARS TO BE A MAINLY DRY COLD FRONT TO THE AREA ON

SATURDAY.

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