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Dec 11-13 MW/Lakes/OV Snow Event? Part II


Chicago Storm

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BUCK-

LSE should breaks out the chains and hammers and straighten out the rest of these offices.

THEN FOCUS TURNS TO DEVELOPING LOW PRESSURE OVER THE CENTRAL

AND SOUTHERN PLAINS STATES FRIDAY NIGHT INTO SATURDAY. THE 08.12Z

GFS AND NAM ARE IN AGREEMENT WITH A FARTHER SOUTH AND COOLER

SOLUTION...WITH DIFFERENCES IN TIMING OF SHORTWAVE TROUGH MOVING

ACROSS THE FORECAST AREA. THE LATEST 08.12Z ECMWF INDICATING A

FARTHER NORTH AND WARMER SOLUTION. WITH THE 08.12Z ECMWF WETTER AND

WARMER SOLUTION...COMBINED WITH STRONG WINDS ON THE BACKSIDE OF THE

SURFACE LOW. THIS SOLUTION WOULD HAVE MAJOR IMPACTS ACROSS THE AREA.

HOWEVER...THE 08.12Z GFS AND NAM ARE COLDER AND DRIER SOLUTIONS...

HENCE PRODUCE LESS SNOW. HOWEVER...

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Is this type of setup more supportive of LES between London and Barrie? You mentioned elsewhere that last weekend's storm was a... oh what was it... 334/500 storm? Which is typically not supportive of LES around this area I think you said?

:lmao: You're a bit off there.

Probably too early to get into the specifics of wind direction, but looking at the GFS sfc plots, it looks like it'll be a NNW event again (320-330) and thereabouts.

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I gotta laugh....I don't care what anyone says....there is a definite backyard bias amongst NWS offices wrt situations like this. I'm not picking on any single region, I think it's pretty much across the board. Below is a clip from BUF:

IT APPEARS VERY LIKELY THAT A STRONG SURFACE LOW WILL

DEVELOP AS A DEEP AND INCREASINGLY NEGATIVE TILTED UPPER TROF ENTERS

APPROACHES THE EAST COAST. THE PART THE MODELS ARE STRUGGLING WITH

IS IF/WHEN/WHERE A COASTAL LOW WILL DEVELOP. STILL FEEL THAT FROM A

CLIMATOLOGICAL STANDPOINT...A COASTAL DEVELOPMENT IS FAVORED GIVEN

THE FAVORABLE BAROCLINIC ZONE ALONG THE EASTERN SEABOARD. WHILE NOT

TOO MUCH IS READ IN THE SPECIFICS...THE OPERATIONAL GFS APPEARS MUCH

MORE PLAUSIBLE THAN THE EUROPEAN/GGEM...AND IS MUCH MORE IN LINE

WITH OUR GOING FORECAST.

That is sort of necessary though. Clearly we're all weenies too (well most of us at least), but part of the job is to properly convey threats to the public. And if one particular model is showing a solution that poses a threat, the possibility should be discussed. Not necessarily forecast, but at least discussed. Plus I think it's a pretty common bias for most people to accept a solution that validates their own thinking. It's difficult to completely remove sometimes, but emotion should play no part in a forecast.

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I gotta laugh....I don't care what anyone says....there is a definite backyard bias amongst NWS offices wrt situations like this. I'm not picking on any single region, I think it's pretty much across the board. Below is a clip from BUF:

IT APPEARS VERY LIKELY THAT A STRONG SURFACE LOW WILL

DEVELOP AS A DEEP AND INCREASINGLY NEGATIVE TILTED UPPER TROF ENTERS

APPROACHES THE EAST COAST. THE PART THE MODELS ARE STRUGGLING WITH

IS IF/WHEN/WHERE A COASTAL LOW WILL DEVELOP. STILL FEEL THAT FROM A

CLIMATOLOGICAL STANDPOINT...A COASTAL DEVELOPMENT IS FAVORED GIVEN

THE FAVORABLE BAROCLINIC ZONE ALONG THE EASTERN SEABOARD. WHILE NOT

TOO MUCH IS READ IN THE SPECIFICS...THE OPERATIONAL GFS APPEARS MUCH

MORE PLAUSIBLE THAN THE EUROPEAN/GGEM...AND IS MUCH MORE IN LINE

WITH OUR GOING FORECAST.

I have read several disco's coming out of the mid-west this afternoon, as well as the MS Valley, and that seems to be the general flavor of discounting the 12z EC for either latent heat feedback, or lack of continuity, and siding with the GFS UK solution. Not sure how much certainty there is in either one at this point, or most of the AFD's I have read today, but a heavy bias atm towards the latter solutions. This one from KSGF sounds similar...

THAT UPPER LEVEL WAVE WILL CONTINUE TO DIG AS WE GET INTO THE

SATURDAY AND SATURDAY NIGHT PERIOD. MODELS CONTINUE TO OFFER A

VARIETY OF SOLUTIONS. THE NAM WAS IGNORED AS IT WILL LIKELY

CONTINUE TO PLAY CATCH UP WITH THE GLOBAL MODELS THE NEXT FEW

RUNS. THE 12Z ECMWF WAS ALSO IGNORED FOR TWO REASONS. GIVEN THAT

THE LONG WAVE TROUGH AXIS RESIDES OVER THE EASTERN UNITED

STATES...IT IS TOO QUICK TO CLOSE OFF THE UPPER LEVEL LOW. IN

ADDITION...THE ECMWF SEEMS TO BE TOO QUICK TO STOP DIGGING THE LOW

GIVEN THE STRENGTH OF THE UPPER LEVEL JET STREAK ON THE WESTERN

FLANK OF THE DIGGING ENERGY. THE 12Z UKMET AND GFS APPEAR MUCH

MORE BELIEVABLE KEEPING THE WAVE PRETTY MUCH OPEN AND QUICKLY

PROGRESSING SOUTHEAST. THIS ENERGY WILL FINALLY BEGIN TO TAKE THE

TURN EAST AS IT ENCOUNTERS THAT LONG WAVE TROUGH AXIS BY SUNDAY.

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Henry Margusity is still talking about this storm transferring to the coast. I haven't seen this anywhere else. Is this supported or just wishcasting?

Wishcasting, which is sad coming from a Met. If he gave sound reasoning it would be different, but he is riding the GFS's attempt at forming a coastal

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Most AFD's seem to be discounting the 12z EURO:

Springfield, MO NWS:

THAT UPPER LEVEL WAVE WILL CONTINUE TO DIG AS WE GET INTO THE

SATURDAY AND SATURDAY NIGHT PERIOD. MODELS CONTINUE TO OFFER A

VARIETY OF SOLUTIONS. THE NAM WAS IGNORED AS IT WILL LIKELY

CONTINUE TO PLAY CATCH UP WITH THE GLOBAL MODELS THE NEXT FEW

RUNS. THE 12Z ECMWF WAS ALSO IGNORED FOR TWO REASONS. GIVEN THAT

THE LONG WAVE TROUGH AXIS RESIDES OVER THE EASTERN UNITED

STATES...IT IS TOO QUICK TO CLOSE OFF THE UPPER LEVEL LOW. IN

ADDITION...THE ECMWF SEEMS TO BE TOO QUICK TO STOP DIGGING THE LOW

GIVEN THE STRENGTH OF THE UPPER LEVEL JET STREAK ON THE WESTERN

FLANK OF THE DIGGING ENERGY. THE 12Z UKMET AND GFS APPEAR MUCH

MORE BELIEVABLE KEEPING THE WAVE PRETTY MUCH OPEN AND QUICKLY

PROGRESSING SOUTHEAST. THIS ENERGY WILL FINALLY BEGIN TO TAKE THE

TURN EAST AS IT ENCOUNTERS THAT LONG WAVE TROUGH AXIS BY SUNDAY.

St. Louis AFD:

STILL A LOT OF MODEL UNCERTAINTY WITH THE

POSITION AND TRACK OF THE MAIN VORT MAX AND SFC LOW. FOR NOW

FOLLOWED THE GFS MODEL AS IT HAS BEEN THE MOST CONSISTENT. THIS

MODEL DOES NOT CLOSE OFF A 500 MB LOW BUT DOES DEEPEN A SFC/850 MB

LOW SE OF THE AREA. IT APPEARS THAT THE BETTER SNOW ACCUMULATION

MAY OCCUR FROM STL NEWD TOWARDS SPI SAT NGT AS THE STORM SYSTEM

INTENSIFIES AS IT MOVES E OF THE AREA. STRONG AND GUSTY NWLY SFC

WINDS BEHIND THE CDFNT WILL BRING MUCH COLDER AIR TO THE REGION

FOR SAT NGT AND SUN. THE SNOW SHOULD TAPER OFF TO FLURRIES SUN

MRNG...ALTHOUGH IF THE SLOWER...CLOSED OFF SOLUTION OF THE ECMWF

MODEL WERE TO VERIFY THE SNOW WOULD BE SLOWER TO END ACROSS IL.

DVN AFD:

OVERVIEW...MODEL INITIALIZATION AND VERIFICATION GOOD EXCEPT FOR HI-

RES ECMWF WHICH SUFFERS FROM LATENT HEAT RELEASE FEEDBACK ISSUES FOR

SATURDAY. ALL OTHER SOLUTIONS TRENDING FURTHER SOUTH WITH DEEP UPPER

TROUGH THIS WEEKEND TO LIMIT WEEKEND SNOW AMOUNTS. WELL BELOW TO

BELOW NORMAL TEMPERATURES INTO NEXT WEDNESDAY WITH SNOW COVERED AREAS

BELOW ZERO AT TIMES. USED A 60/40 BLEND OF 80KM NAM-WRF FORCING AND

GFS INTO SATURDAY. SATURDAY ON...USED A BLEND OF GFS/UKMET AND GEM-

NH.

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Simply put, as SGF stated, it makes more sense for the trough to continue digging rather than wrapping up.

The 00z Euro op/ensembles ought to be enlightening. If they hold their ground I'll be more cautious to throw them out. Sure it's possible that the 12z run had one glaring initialization error that caused the ensembles to mostly favor a northern track. But initialization is supposed to be the Euro's forte, and ensembles are supposed to mitigate those issues further.

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even the 18Z nocraps holds it own but a little further north

the nocraps pattern for this storm is to lock onto a solution and keep it for approx 4 runs, then switch to a drastically different solution again for 4 runs... I lost count, but i would imagine either tonights 00z run or tmrw's 6z it should flip again.

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It's unbelievably incoherent BUT, notice its emphasis on the northern low/inverted trough now.

Please correct me if I'm wrong, but it seems the GFS is more progressive with the southern s/w, not really digging it until it gets closer to the coast. Also, perhaps the northern s/w is quicker, acting as a kicker which prevents the southern wave from slowing and amplifying?

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