Preliminary Forecasts
Issued by NWS

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000
FXUS02 KWNH 280459
PREEPD

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1259 AM EDT MON JUL 28 2014

VALID 12Z THU JUL 31 2014 - 12Z MON AUG 04 2014

...OVERVIEW...

PERSISTENT RIDGE/TROUGH CONFIGURATION WILL PERSIST THROUGH THE
FIRST SEVERAL DAYS OF AUGUST ACROSS THE CONUS. THE MOST STABLE
ANOMALY OVER NORTH AMERICA WILL BE RIDGING OVER
ALBERTA/SASKATCHEWAN WHERE 500MB HEIGHT ANOMALIES WILL LINGER NEAR
+2. IN THE ATLANTIC... RIDGING WILL INITIALLY BUILD BUILD INTO
NEWFOUNDLAND BEFORE WEAKENING... ONLY TO BE REPLACED BY RIDGING
NORTH OF THE GREATER ANTILLES. ANY WAY YOU SLICE IT... TROUGHING
WILL STILL BE FAVORED BETWEEN 80-90W.

...GUIDANCE PREFERENCES...

MODELS HAVE BEEN ON A STRING OF RATHER CONSISTENT RUNS... ALL
THINGS CONSIDERED... AND A BLEND AMONG THE WELL-CLUSTERED 18Z
GFS/GEFS MEAN AND 12Z ECMWF/ECENS MEAN AGAIN OFFERED A GREAT
STARTING POINT. AT ISSUE WILL BE HOW QUICKLY THE SECOND ROUND OF
TROUGHING... NEXT SUN/MON... WILL EXIT THE OH VALLEY AND ALSO HOW
STRONG INCOMING NORTHERN ENERGY /LIKELY TO STAY IN CANADA/ WILL
BE. THE UPPER LOW IN THE ALEUTIANS REFUSES TO BE KICKED
EASTWARD... DESPITE VARIOUS DETERMINISTIC RUNS THAT SHOWED IT OVER
THE PAST SEVERAL DAYS... WHICH WILL MAKE IT HARD FOR ANY SFC
BOUNDARY TO GET CLOSE TO THE PAC NW.

...SENSIBLE WEATHER HIGHLIGHTS...

PRECIP SHOULD FOCUS OVER CO/NM AT THE END OF THE WEEK AS THE SFC
FRONTAL BOUNDARY HANGS UP EAST OF THE MOUNTAINS. OTHER SIDE OF THE
FRONT WILL STALL JUST OFFSHORE THE EAST COAST BUT WILL BE JUST FAR
ENOUGH EAST EARLY IN THE PERIOD TO ALLOW WEAK HIGH PRESSURE TO
CENTER OVER THE APPALACHIANS. MIDDLE PORTION OF THE FRONT WILL
PUSH QUITE FAR SOUTH INTO FLORIDA AND INTO THE GULF OF MEXICO...
HELPING TO TRIGGER SHOWERS/STORMS IN THE SUNSHINE STATE AND ALSO
INTO THE REST OF THE SOUTHEAST BY THE WEEKEND. FRONT SHOULD CREEP
WESTWARD IN TIME THROUGH MON/D7... SPREADING RAIN WESTWARD PAST
THE I-95 CORRIDOR. WITH THE TROUGH AXIS STILL WELL WEST... THE
EASTERN THIRD OF THE CONUS WILL RUN THE RISK OF RAIN IN THE
UNSTABLE AIRMASS. THE CENTRAL AND HIGH PLAINS SHOULD ENJOY THE
BACKSIDE OF THE TROUGH /NORTHERLY FLOW ALOFT/ AND SFC HIGH
PRESSURE. TEMPERATURES WILL BE ABOUT 10-15F BELOW AVERAGE OVER THE
SOUTHERN PLAINS IN THE COOL/OVERRUNNING ZONE... AND ABOUT 5-10F
BELOW AVERAGE FOR THE REST OF THE CENTRAL/EASTERN STATES. THE WEST
WILL REMAIN SEASONABLY WARM/HOT... WITH THE RELATIVELY HOTTEST
TEMPERATURES /5-10F ABOVE AVERAGE/ IN WA/OR/ID.

FRACASSO

$$




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