Prognostic Meteorological Discussion
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FXUS02 KWBC 101558
PMDEPD

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1157 AM EDT THU JUL 10 2014

VALID 12Z SUN JUL 13 2014 - 12Z THU JUL 17 2014

...HEAT TO CONTINUE IN THE PAC NW...

...RECORD COLD POSSIBLE IN THE CENTRAL/SOUTHERN PLAINS AND GREAT
LAKES REGION...


...OVERVIEW AND GUIDANCE PREFERENCES...

A HIGHLY ANOMALOUS AMPLIFICATION OF THE FLOW ACROSS NORTH AMERICA
IS INDICATED BY THE GLOBAL NUMERICAL MODELS AT THE MEDIUM RANGE. A
DEEP UPPER LOW... NOT THE POLAR VORTEX AS ITS ORIGINS ARE FROM THE
NE PACIFIC... WILL SWING THROUGH THE GREAT LAKES EARLY NEXT WEEK
WITH AN IMPRESSIVE COLD SHOT OF AIR INTO THE CENTRAL AND THEN
SOUTHERN PLAINS AND THE MIDWEST. THE EUROPEAN CENTRE ENSEMBLE MEAN
HAS BEEN THE STEADIEST OF THE MEANS FROM THE VARIOUS MODELING
CENTERS OVER THE PAST FEW DAYS OF DATA CYCLES... AND THE
DETERMINISTIC MODELS HAVE MOSTLY CONVERGED TOWARDS ITS IDEA. THE
ECMWF... THOUGH IT HAS BEEN ON THE EXTREME SIDE OF THE ENTIRE
ENSEMBLE SPREAD... HAS BEEN INSISTENT ON ADVERTISING QUITE THE
TEMPERATURE EXTREMES -- BOTH HOT AND COLD -- FOR THE CONUS NEXT
WEEK. THE GFS HAS BEEN GENERALLY WITHIN THE ENSEMBLE SPREAD OVER
THE LAST 48 HRS BUT LAGS BEHIND THE GREATER CLUSTER OF THE
ECMWF/CMC/UKMET WITH THE FRONTAL PROGRESSION THROUGH THE SOUTHERN
PLAINS EARLY NEXT WEEK. RELIED ON A CONSENSUS BLEND EARLY IN THE
PERIOD BEFORE TRENDING TO A ECMWF/ECENS/GEFS BLEND FOR THE BALANCE
OF THE FORECAST... WHICH MAINTAINS CONTINUITY WELL.


...SENSIBLE WEATHER HIGHLIGHTS...

THE IMPRESSIVE FULL-LATITUDE RIDGE OVER THE WEST IS EXPECTED TO
SEND TEMPERATURES SOARING OVER EASTERN WASHINGTON AND THE ADJACENT
LOWLANDS OF OREGON AND IDAHO. AFTERNOON HIGHS MAY WELL RANGE
BETWEEN 100F AND 110F FOR MUCH OF THE PERIOD... CLOSE TO RECORD
HIGHS FOR BOTH MAX AND MIN. PRECIP SHOULD BE SCARCE OR
NON-EXISTENT WEST OF THE DIVIDE IN THE NORTHERN ROCKIES. FOR THE
CENTRAL/EASTERN/SOUTHERN CONUS... THE UPPER LOW WILL CARRY A LEAD
SFC BOUNDARY EASTWARD AND SOUTHWARD WITH A REINFORCING COLD PUSH
BEHIND IT. TEMPERATURE ANOMALIES ALOFT DROP INTO THE -2 TO -3
STANDARD DEVIATIONS RANGE PER THE ENSEMBLE MEANS. SPC HAS
HIGHLIGHTED A SEVERE THREAT IN THE NORTHEAST/I-95 CORRIDOR ON
TUE/D5 IN ADVANCE OF THE FRONT. INDEED CONVECTION IS POSSIBLE IF
NOT LIKELY ALONG ITS PATH... WHICH WILL MODULATE THE SPEED OF THE
FRONTAL PROGRESSION INTO THE SOUTH. DESPITE BEING NEAR THE CLIMO
MAX TIME OF THE YEAR FOR TEMPERATURES... THE MODELS INDICATE THAT
THE SFC BOUNDARY WILL HEAD TOWARD THE GULF COAST BY LATE NEXT
WEEK... THOUGH IN A WEAKENED STATE. THE BELOW AVERAGE TEMPERATURES
SHOULD SPREAD SOUTHWARD BEHIND THE FRONT INTO TX/OK WHERE RECORD
LOW MINS/MAXES ARE POSSIBLE AS 850 TEMPS DROP TO NEAR MONTHLY
RECORD LOWS.


FRACASSO/CISCO

$$




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