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Ntxw wrote:That's amazing though yet again I think the big storm is being pushed back some.
iorange55 wrote:lol this is ridiculous. The new GFS is basically predicting the end of the world
Ntxw wrote:And I thought 18z was a eye candy...
Edit: At least this will be during the time frame that everyone's at home for the holidays IF it is to be believed
OT: Hey is dem' Saints gonna beat dem' Cowboys in the dome on Saturday night? As they say in NOLA "GEAUX SAINTS, BLESS YOU BOYS".southerngale wrote:Btw, I've seen a lot of new members joining and posting recently, particularly quite a few new Texas posters. Welcome to all of you!
any news from the EC?
Ntxw wrote:Should the 12z run continue to verify (I don't trust 18z and 6z runs very much) I'll be a happy camper
Portastorm wrote:Oh, and I think it is now time to post this ... ALL ABOARD!!!!! The Polar Express is about the leave the station.
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
311 AM EST WED DEC 16 2009
VALID 12Z SUN DEC 20 2009 - 12Z WED DEC 23 2009
A FAIRLY COMPLEX LONGWAVE PATTERN IS EXPECTED TO PREVAIL DURING
THE MEDIUM RANGE PERIOD WITH A REX-BLOCK RETROGRADING FROM THE
NORTHERN ATLANTIC TO EASTERN CANADA...A SPLIT-FLOW REGIME
PREVAILING OVER CENTRAL CANADA...AND AN AMPLIFYING TROUGH OVER THE
NORTHERN PACIFIC WHICH MAINTAINS SPLIT-FLOW ALONG THE WEST COAST
AS WELL UNTIL AT LEAST DAY 5. WHILE LONGWAVE FLOW AGREEMENT IS
REASONABLY GOOD THIS CYCLE...DETAIL DIFFERENCES ARE INHERENTLY
LARGE AND GROW WITH TIME...WITH MUCH OF THE UNCERTAINTY
ORIGINATING FROM THE NORMALLY MORE COMPLEX HIGHER LATITUDES WHERE
MODEL INITIALIZATION IS TYPICALLY WORSE. THUS...THE APPROACH
DURING THE MEDIUM RANGE PERIOD IS TO USE DETERMINISTIC SOLUTIONS
AS MUCH AS IS REASONABLY POSSIBLE EARLY TO MAINTAIN DETAIL BUT
THEN SWITCH TO ENSEMBLES LATER IN THE PERIOD. THERE EXISTS SEVERAL
DAY-T0-DAY MODEL DIFFERENCES TO CONTEND WITH...THE EARLIEST OF
WHICH WILL EXIST ALONG THE EAST COAST...WITH ALL MODELS TRENDING
FARTHER OFFSHORE AND FASTER WITH A DEEPENING CYCLONE...WITH THE
ECMWF TAKING AN UNUSUAL TURN TOWARD THE WEST AS THE LOW REACHES
THE CANADIAN MARITIMES BY DAY 6. THUS...WILL STAY CLOSER TO THE
CONSENSUS BY THIS TIME WHICH CONTINUES TO EJECT THE LOW INTO THE
NORTHERN ATLANTIC. BEFORE THEN HOWEVER...
MODEL SOLUTIONS ARE QUITE CLOSE WITH THE TRACK OF THE LOW.
MEANWHILE...IN THE NORTHWEST THE ECMWF IS NEARLY A FAST OUTLIER
WITH A SMALL UPPER LOW DRIFTING INTO THE REGION BY DAY 5...WITH
THE GFS ABOUT 1-2 DAYS SLOWER. THE CANADIAN AND GEFS MEAN OFFER A
REASONABLE COMPROMISE HERE GIVEN THE SPREAD...WITH THE ECMWF
CONSIDERED UNLIKELY GIVEN THAT ITS SOLUTION IS OUT OF PHASE WITH
OTHER GUIDANCE OVER THE NORTHEAST PACIFIC. FINALLY...THE
SPLIT-FLOW REGIME OVER CENTRAL CANADA SHOULD FAVOR A REGULAR BUT
UNCERTAIN FLOW OF SHORTWAVE TROUGHS FROM WESTERN CANADA THROUGH
THE DAKOTAS AND EAST WHICH WILL BE DIFFICULT TO TIME. THUS...WILL
USE A 50/50 BLEND OF THE GFS/ECMWF THROUGH DAY 5 BEFORE COMPLETELY
ABANDONING DETERMINISTIC GUIDANCE IN FAVOR OF 100 PERCENT GEFS
MEAN BY DAY 7.
JAMES
BOTH THE GFS AND ECMWF ATTEMPT TO BRING A STRONG LOW PRESSURE SYSTEM
BY THE MIDDLE OF NEXT WEEK. THOUGH LOW CONFIDENCE PREVENTS US FROM
ADDING POPS AT THIS TIME...THIS SYSTEM COULD AFFECT HOLIDAY TRAVELERS
WEDNESDAY THROUGH FRIDAY OF NEXT WEEK AND SOMEWHERE FROM THE CENTRAL
TO EASTERN U.S.
NUNEZ
weatherguy425 wrote:So as far as not following the ECMWF does that mean they're thinking a warmer solution or just drier?
Perhaps at the moment they are not buying the BIG STORM shown by the ECMWF for Christmas Eve just yet...
iorange55 wrote:Perhaps at the moment they are not buying the BIG STORM shown by the ECMWF for Christmas Eve just yet...
but they're buying into the GFS big storm? They're both showing big storms, so are they going with another model?
srainhoutx wrote:iorange55 wrote:Perhaps at the moment they are not buying the BIG STORM shown by the ECMWF for Christmas Eve just yet...
but they're buying into the GFS big storm? They're both showing big storms, so are they going with another model?
Hmmm, I don't see such a big storm on the GFS in the same time frame. We shall see...
PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
821 AM EST WED DEC 16 2009
VALID 12Z SUN DEC 20 2009 - 12Z WED DEC 23 2009
A FAIRLY COMPLEX LONGWAVE PATTERN IS EXPECTED TO PREVAIL DURING
THE MEDIUM RANGE PERIOD WITH A REX-BLOCK RETROGRADING FROM THE
NORTHERN ATLANTIC TO EASTERN CANADA...A SPLIT-FLOW REGIME
PREVAILING OVER CENTRAL CANADA...AND AN AMPLIFYING TROUGH OVER THE
NORTHERN PACIFIC WHICH MAINTAINS SPLIT-FLOW ALONG THE WEST COAST
AS WELL UNTIL AT LEAST DAY 5. WHILE LONGWAVE FLOW AGREEMENT IS
REASONABLY GOOD THIS CYCLE...DETAIL DIFFERENCES ARE INHERENTLY
LARGE AND GROW WITH TIME...WITH MUCH OF THE UNCERTAINTY
ORIGINATING FROM THE NORMALLY MORE COMPLEX HIGHER LATITUDES WHERE
MODEL INITIALIZATION IS TYPICALLY WORSE. THUS...THE APPROACH
DURING THE MEDIUM RANGE PERIOD IS TO USE DETERMINISTIC SOLUTIONS
AS MUCH AS IS REASONABLY POSSIBLE EARLY TO MAINTAIN DETAIL BUT
THEN SWITCH TO ENSEMBLES LATER IN THE PERIOD. THERE EXISTS SEVERAL
DAY-T0-DAY MODEL DIFFERENCES TO CONTEND WITH...THE EARLIEST OF
WHICH WILL EXIST ALONG THE EAST COAST...WITH ALL MODELS TRENDING
FARTHER OFFSHORE AND FASTER WITH A DEEPENING CYCLONE...WITH THE
ECMWF TAKING AN UNUSUAL TURN TOWARD THE WEST AS THE LOW REACHES
THE CANADIAN MARITIMES BY DAY 6. THUS...WILL STAY CLOSER TO THE
CONSENSUS BY THIS TIME WHICH CONTINUES TO EJECT THE LOW INTO THE
NORTHERN ATLANTIC. BEFORE THEN HOWEVER...
MODEL SOLUTIONS ARE QUITE CLOSE WITH THE TRACK OF THE LOW.
MEANWHILE...IN THE NORTHWEST THE ECMWF IS NEARLY A FAST OUTLIER
WITH A SMALL UPPER LOW DRIFTING INTO THE REGION BY DAY 5...WITH
THE GFS ABOUT 1-2 DAYS SLOWER. THE CANADIAN AND GEFS MEAN OFFER A
REASONABLE COMPROMISE HERE GIVEN THE SPREAD...WITH THE ECMWF
CONSIDERED UNLIKELY GIVEN THAT ITS SOLUTION IS OUT OF PHASE WITH
OTHER GUIDANCE OVER THE NORTHEAST PACIFIC. FINALLY...THE
SPLIT-FLOW REGIME OVER CENTRAL CANADA SHOULD FAVOR A REGULAR BUT
UNCERTAIN FLOW OF SHORTWAVE TROUGHS FROM WESTERN CANADA THROUGH
THE DAKOTAS AND EAST WHICH WILL BE DIFFICULT TO TIME. THUS...WILL
USE A 50/50 BLEND OF THE GFS/ECMWF THROUGH DAY 5 BEFORE COMPLETELY
ABANDONING DETERMINISTIC GUIDANCE IN FAVOR OF 100 PERCENT GEFS
MEAN BY DAY 7 FOR EARLY PRELIMS.
UPDATED MORNING PRELIMS FAVOR ECMWF AND THE 00Z ECMWF ENS MEANS
THRU THE PERIOD WITH AN INCREASING AMOUNT OF THE MEANS THRU THE
PERIOD. THIS PRODUCES MINIMAL SFC CHANGES BUT 00Z ECMWF ENS MEANS
LOOKS CLOSE TO THE OP 0Z ECMWF AND 00Z GFS ENS MEANS LATE PERIOD
DEVELOPING A HIGH AMPLITUDE TROF OVER THE INTERMTN REGION INSTEAD
OF THE RIDGING BY THE OP 0Z GFS. THIS ALSO ELIMINATES THE DEEP
GREAT LAKES VORTEX OF GFS BY DAY 7.
MODERATELY STRONG LOW PRESSURE COMING OFF THE SOUTHEAST SEABOARD
SATURDAY WILL BRING SOME HVY COASTAL RAINS AND BRISK NE WINDS TO
THE LOWER MID ATLC COAST BEFORE MOVING NEWD. RECENT
OP MODELS HAVE SHIFTED THE SFC TRACK EWD LOWERING THE INLAND AND
MORE NWD SNOW THREAT OVER THE INTERIOR MID ATLC REGION NAD
NORTHEAST. SUBTLE CHANGES IN THE DIGGING MID LEVEL TROF AND
DOWNSTREAM RIDGING ALLOWED FOR PREVIOUS SOLUTIONS ESPECIALLY ECMWF
AND CMC HAVING A MORE WWD SFC TRACK. STRONG NEG AO/NAO IN PLACE
AND TRANSITION TO A POSITIVE PNA WITH ENOUGH AMBIENT COLD AIR
OFTEN A SET FOR ERN CONUS SNOW EVENTS HOWEVER IT ALWAYS REMAINS
QUITE CRITICAL AND DEPENDENT UPON SFC AND MID LEVEL FEATURES
LOCATIONS. TODAYS OP MODEL RUNS SHUNT THIS EWD ENOUGH FOR A STAND
DOWN ON A SNOW THREAT. HOWEVER LAGGED AVERAGE FORECAST OF OF ECMWF
AND GFS STILL INDICATE A POSSIBILITY OF A MORE INTENSE AND WEST
SFC TRACK CLOSER TO PRIOR ECMWF/CMC RUNS AND THE MAJORITY OF BOTH
CMC AND ECMWF ENSEMBLE MEMBER SFC LOWS ARE CONSIDERABLY WESTWARD
OF THE OP MODEL RUNS WITH HALF OF TEH GFS MEMBERS ALSO WEST. THEIR
RESPECTIVE ENS MEAN PCPN OUTPUT IS CONSIDERABLY WETTER WESTWARD
AND WELL INLAND OVER THE MID ATLC AND SOUTHEAST NEW ENGLAND THAN
THE OP MODELS. THIS HAS BEEN TAKEN INTO CONSIDERATION WITH HPC
POPS. A RECURRENT ANALOG OVER THE PAST SEVERAL DAYS HAS BEEN THE
EVENT OF 23-24 DEC 1966.
JAMES/ROSENSTEIN
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