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Feb. 8-12 Model Discussion Part III


beanskip

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CAE.....:rolleyes:

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...

-- Changed Discussion --CONFIDENCE CONTINUES TO REMAIN LOW WITH THE STORM SYSTEM EXPECTED

TO IMPACT THE FORECAST AREA LATE WEDNESDAY NIGHT INTO EARLY

THURSDAY. MODEL GUIDANCE CONTINUES TO DIFFER WITH RESPECT TO A

SURFACE LOW EXPECTED TO TRACK ALONG THE GULF COAST...ACROSS THE

GA/FL BORDER AND OFF THE SOUTHEAST COAST. THE NAM CONTINUES TO BE

THE STRONGEST WITH THE SURFACE LOW AND UPPER SYSTEM WHILE THE GFS

CONTINUES TO DOWNPLAY THE SYSTEM SHEARING OUT THE UPPER ENERGY AND

DEVELOPS THE SURFACE LOW OFF THE CAROLINA COAST. NAM APPEARS AS

THE OUTLIER AMONG THE MODEL GUIDANCE INCLUDING THE SREF/NCEP

ENSEMBLES/CANADIAN/ECMWF. NAM CONTINUES TO BE THE COLDEST IN THE

LOWER LEVELS OF THE ATMOSPHERE COMPARED TO OTHER GUIDANCE. THIS

SYSTEM AS A WHOLE DOES NOT APPEAR TO BE STRONGLY FORCED AND THE

MAIN FORCING OCCURS ABOVE THE SNOW GROWTH ZONE AND THE LOWER

LEVELS ARE LIKELY TO BE DRY INITIALLY. ANOTHER FACTOR WITH THIS

SYSTEM IS THAT THE SYSTEM WILL BE MOVING QUICKLY THROUGH THE AREA

WITH THE MAIN WINDOW OF PRECIPITATION OCCURRING BETWEEN AROUND 4

AM THROUGH 11 AM THURSDAY.

GIVEN THE UNCERTAINTIES AND THROUGH COORDINATION WITH SURROUNDING

OFFICES...HAVE OPTED TO LOWER POPS BACK TO HIGH CHANCE WEDNESDAY

NIGHT INTO EARLY THURSDAY MORNING WITH QUICKLY DIMINISHING POPS

EARLY THURSDAY AFTERNOON. FOR ANY PRECIPITATION THAT

FALLS...PRECIPITATION TYPE WILL START OUT AS RAIN OR RAIN/SNOW

MIX THEN CHANGE TO SNOW NORTH OF I-20 AND REMAIN MAINLY RAIN SOUTH

OF I-20. RELATIVELY WARM GROUND/ROAD TEMPERATURES WILL LIKELY

PREVENT MUCH IN THE WAY OF ACCUMULATION. REGARDING

ACCUMULATIONS...DO NOT EXPECT MUCH...POSSIBLY UP TO AN INCH ACROSS

NORTHERN AND WESTERN MIDLANDS TO MAYBE A DUSTING IN THE METRO

AREA. AGAIN THERE REMAINS ALOT OF UNCERTAINTY WITH THIS EVENT AND

CONFIDENCE REMAINS LOW.

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Add to this list- 15Z SREF 2.5-3"

WSI RPM 3"

Thanks, Cheez.

ATL-AHN estimated snow for 12Z Tue runs (vs. yesterday at 12Z):

CMC: 4" (vs. 1" )

JMA: 3.5" (vs.1.5")

UKMET: 2.5" (vs. ~3")

Euro: 2.5" (vs. 2.5")

NAM: 2" (vs. 4")

GFS: 1" (vs. 0")

WSI RPM 3" (vs. ?)

15Z SREF 2.5-3" (vs. ?)

Avg: 2.7" (vs. 2")

So, the consensus is ~35% wetter than yesterday. The CMC, JMA, and GFS are wetter while the NAM is drier. UKMET is ~same.

Based on this added Cheez data for the RPM and SREF, I've decided to raise my best guess for KATL and vicinity Wed. night up to 2.5" from the 2" of earlier this afternoon. If wetter trends continue, the next guess will be wetter.

EDIT: The drier 18Z NAM will be ignored as it puts out only ~1" and the qpf pattern looks kind of funky.

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So, the consensus is ~35% wetter than yesterday. The CMC, JMA, and GFS are wetter while the NAM is drier. UKMET is ~same.

Based on this added Cheez data for the RPM and SREF, I've decided to raise my best guess for KATL and vicinity Wed. night up to 2.5" from the 2" of earlier this afternoon. If wetter trends continue, the next guess will be wetter.

New NAM and NWS FFC do not agree:

post-357-0-15441200-1297196333.gif

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Well this would suck for MBY-looks odd though and does match other guidance. Will ignore for now.

jeesh - that would suck for a lot of the ga and carolina posters back yards. :axe: talk about an irritating event if we have to watch it literally snow all around us but not in oby

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Thanks, Cheez.

ATL-AHN estimated snow for 12Z Tue runs (vs. yesterday at 12Z):

CMC: 4" (vs. 1" )

JMA: 3.5" (vs.1.5")

UKMET: 2.5" (vs. ~3")

Euro: 2.5" (vs. 2.5")

NAM: 2" (vs. 4")

GFS: 1" (vs. 0")

WSI RPM 3" (vs. ?)

15Z SREF 2.5-3" (vs. ?)

Avg: 2.7" (vs. 2")

So, the consensus is ~35% wetter than yesterday. The CMC, JMA, and GFS are wetter while the NAM is drier. UKMET is ~same.

Based on this added Cheez data for the RPM and SREF, I've decided to raise my best guess for KATL and vicinity Wed. night up to 2.5" from the 2" of earlier this afternoon. If wetter trends continue, the next guess will be wetter.

EDIT: The drier 18Z NAM will be ignored as it puts out only ~1" and the qpf pattern looks kind of funky.

If your going to include the Short Range ensembles (SREF), why exclude the GFS ensembles?

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ATL-AHN estimated snow for 12Z Tue runs (vs. yesterday at 12Z):

CMC: 4" (vs. 1" )

JMA: 3.5" (vs.1.5")

UKMET: 2.5" (vs. ~3")

Euro: 2.5" (vs. 2.5")

NAM: 2" (vs. 4")

GFS: 1" (vs. 0")

WSI RPM 3" (vs. ?)

Avg: 2.6" (vs. 2")

So, the consensus is ~30% wetter than yesterday. The CMC, JMA, and GFS are wetter while the NAM is drier. UKMET is ~same.

Based on this added Cheez data for the RPM, I've decided not to raise my best guess for KATL and vicinity Wed. from the 2" of earlier this afternoon. If wetter trends continue, the next guess will be wetter.

EDIT: The drier 18Z NAM will be ignored as it puts out only ~1" and the qpf pattern looks kind of funky.

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Long time lurker first time poster. Just wanted to say I have learned a lot reading and watching all that is posted over the last few months. Thanks to all that post here and help us weather newbs learn! That being said it seems I am always smack in the middle of the bermuda snow triangle here in Cornelius, NC ( about 20 miles north of charlotte). Hopefully we can get a warm up here soon because I'm ready to hit the golf course in some good weather!

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:huh:

Winter Storm Watch

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC

304 PM EST TUE FEB 8 2011

...A SIGNIFICANT SNOWFALL IS POSSIBLE ACROSS ALL OF EASTERN NORTH

CAROLINA WEDNESDAY NIGHT AND THURSDAY MORNING...

.WEAK LOW PRESSURE IS FORECAST TO DEVELOP OFF THE NORTH CAROLINA

COAST WEDNESDAY NIGHT AND CIRCULATE MOISTURE INTO A MARGINALLY

COLD AIR MASS OVER EASTERN NORTH CAROLINA. THIS WILL LEAD TO THE

DEVELOPMENT OF SNOW...POSSIBLY HEAVY AT TIMES...LATE WEDNESDAY

NIGHT AND EARLY THURSDAY MORNING. THE PRECIPITATION IS LIKELY TO

START AS RAIN...OR MIX OF RAIN AND SNOW ALONG THE COAST BEFORE

CHANGING OVER TO ALL SNOW THURSDAY MORNING. INLAND ONLY SNOW IS

EXPECTED TO OCCUR. THE HEAVIEST SNOWS WILL COINCIDE WITH THE

THURSDAY MORNING RUSH HOUR CREATING DANGEROUS DRIVING CONDITIONS

ACROSS THE AREA. THE SNOW IS EXPECTED TO END EARLY THURSDAY

AFTERNOON.

...A WINTER STORM WATCH IS IN EFFECT FROM WEDNESDAY EVENING

THROUGH THURSDAY MORNING...

Think the NAM is a little south with that heavier axis which is shows in SE NC. Basing this mostly on other guidance, RGEM, GFS ens mean, Euro, etc, and the fact these systems tend to come north just a bit at this range. Best educated guess would be Lumberton-Kinston-Washington, areas south of that line may not be an all SN event, while areas to the north will likely stay all SN. Not sure on amounts yet, but a general 0.25-0.5" along that line seems reasonable at this stage. Not buying into a widespread >0.5" QPF event yet, as the overall setup does not look impressive, and as mentioned by others, there is a limit to how wet this can get.

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KILM

HAZARDOUS WEATHER OUTLOOK

NATIONAL WEATHER SERVICE WILMINGTON NC

310 PM EST TUE FEB 8 2011

NCZ100-101-SCZ032>034-092015-

BRUNSWICK-NEW HANOVER-FLORENCE-MARION-HORRY-

310 PM EST TUE FEB 8 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST NORTH CAROLINA AND

NORTHEAST SOUTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

RAIN MAY MIX WITH SNOW WEDNESDAY NIGHT...POSSIBLY PERSISTING INTO

THURSDAY MORNING BEFORE ENDING. AT THIS TIME ACCUMULATIONS ARE

EXPECTED TO TOTAL LESS THAN A HALF INCH...WITH NO SNOW

ACCUMULATION THE MOST LIKELY SCENARIO. SMALL CHANGES IN EVENTUAL

TRACK OF THE LOW PRESSURE SYSTEM OFFSHORE MAY MAKE LARGE

DIFFERENCES IN SNOWFALL FORECASTS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

$$

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KILM

HAZARDOUS WEATHER OUTLOOK

NATIONAL WEATHER SERVICE WILMINGTON NC

310 PM EST TUE FEB 8 2011

NCZ100-101-SCZ032>034-092015-

BRUNSWICK-NEW HANOVER-FLORENCE-MARION-HORRY-

310 PM EST TUE FEB 8 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST NORTH CAROLINA AND

NORTHEAST SOUTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

RAIN MAY MIX WITH SNOW WEDNESDAY NIGHT...POSSIBLY PERSISTING INTO

THURSDAY MORNING BEFORE ENDING. AT THIS TIME ACCUMULATIONS ARE

EXPECTED TO TOTAL LESS THAN A HALF INCH...WITH NO SNOW

ACCUMULATION THE MOST LIKELY SCENARIO. SMALL CHANGES IN EVENTUAL

TRACK OF THE LOW PRESSURE SYSTEM OFFSHORE MAY MAKE LARGE

DIFFERENCES IN SNOWFALL FORECASTS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

$$

:thumbsup: So you are saying there's a chance! All I can say is, here we ao again! Do I really want to get my hopes up?

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Afternoon discussion blurb

KILM

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...

-- Changed Discussion --AS OF 3 PM TUESDAY...MAIN CHALLENGE IS THE POTENTIAL FOR SNOW OR

MIXED PRECIP WITH THE SYSTEM WEDNESDAY NIGHT INTO THURSDAY

MORNING. IT REMAINS A SURPRISINGLY LOW-CONFIDENCE FORECAST EVEN IN

THE FACE OF GFS AND NAM AGREEING WITH EACH OTHER...BECAUSE THEY DO

NOT AGREE AS MUCH WITH PREVIOUS RUNS.

LARGEST SOURCE OF UNCERTAINTY...EVEN IF THE MODELS ARE ON THE

MONEY...IS WHETHER THERE WILL BE ENOUGH MOISTURE AVAILABLE FOR THE

FRONTOGENETIC FORCING TO TAP INTO. FGEN FORCING AT 850MB IS

MAXIMIZED AROUND 06Z THU AND GENERATES DECENT ISENTROPIC

LIFT...BUT IT WILL TAKE SOME TIME AFTER THAT TO FULLY OVERCOME

LOW-LEVEL DRY AIR. SFC TEMPS ARE ALSO MARGINAL FOR SNOW BUT MORE

VIGOROUS LIFT WILL COOL THINGS DOWN MORE EFFICIENTLY. BEST SHOT AT

ACCUMULATING SNOW...OR SNOW AT ALL FOR THAT MATTER...IS 06-12Z THU

AND NORTH OF HIGHWAY 76.

WITH SO MANY QUESTION MARKS...AM HESITANT TO TAKE POPS ABOVE HIGH

CHANCE AT ANY POINT. THE CURRENT SNOW ACCUM GRIDS SHOW A HALF INCH

TO 1 INCH IN THE NORTHERN COUNTIES...AND WHILE THAT MAY BE A BIT

GENEROUS IN LIGHT OF POTENTIAL MIXING AND TEMPS NEAR OR SLIGHTLY

ABOVE FREEZING...A GOOD BURST OF SNOW COULD EASILY SURPASS THAT

IF THE FORCING AND THE MOISTURE ACTUALLY COINCIDE. THIS SCENARIO

IS MORE LIKELY NORTH AND EAST OF THE ILM CWA...BUT CANNOT BE

TOTALLY DISCOUNTED IN BLADEN AND ROBESON COUNTIES. COASTAL

COUNTIES COULD VERY WELL SEE A FEW FLAKES FLYING BUT NO

ACCUMULATION IS EXPECTED.

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