Preliminary Forecasts
Issued by NWS

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FXUS02 KWNH 290537
PREEPD

PRELIMINARY EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
136 AM EDT FRI JUL 29 2016

VALID 12Z MON AUG 01 2016 - 12Z FRI AUG 05 2016

...OVERVIEW...

MEDIUM RANGE FORECAST MAINTAINS THE WESTERLIES THROUGH SOUTHERN
CANADA, WELL SOUTH OF AN UPPER LOW MOVING INTO THE CANADIAN
ARCHIPELAGO AROUND 75N. TROUGHING IN INITIALLY IN THE EAST WILL
TREND TOWARD HIGHER HEIGHTS AND WARMER TEMPERATURES FOR THE END OF
NEXT WEEK. THE PAC NW WILL SEE ONE CLOSED LOW SLIDE THROUGH THE
REGION EARLY IN THE WEEK WITH ANOTHER LOOMING TO THE NW NEXT
THU/FRI.


...GUIDANCE ASSESSMENT...

LATEST GFS/ECMWF/CANADIAN RUNS OFFER GOOD ENOUGH CLUSTERING WITH
THEIR ENSEMBLE MEANS TO USE A CONSENSUS BLEND FOR MOST OF THE
PERIOD. ENSEMBLE TREND HAS BEEN A BIT SLOWER AND MORE DEVELOPED
WITH THE SYSTEM THROUGH THE HIGH PLAINS INTO THE GREAT LAKES NEXT
WED-THU. THE 18Z GEFS AND 12Z ECMWF ENSEMBLES WERE NOT EXACTLY IN
LINE THOUGH THE TRENDS SEEM TO FAVOR THE GEFS AT SOME TIMES BUT
THE ECMWF ENSEMBLES AT OTHERS -- E.G. THE GEFS HAD FORECAST A
DEEPER LEAD UPPER LOW IN THE PAC NW BEFORE THE ECENS MEAN, BUT THE
ECENS MEAN HAS BEEN CONSISTENT WITH THE TROUGH AXIS THROUGH THE
GREAT LAKES BY NEXT FRIDAY. BLEND APPROACH SEEMED TO BE A GOOD
STARTING POINT. DISREGARDED THE CANADIAN NEXT THU-FRI AS IT SPINS
UP A TROPICAL SYSTEM IN THE CARIBBEAN AND INTO THE BAY OF CAMPECHE.


...SENSIBLE WEATHER HIGHLIGHTS...

ABOVE AVERAGE TEMPERATURES WILL SPREAD FROM THE CENTRAL PLAINS
EASTWARD AHEAD OF A COLD FRONT MOVING ACROSS THE NORTHERN TIER.
LINGERING STATIONARY BOUNDARY THROUGH THE SOUTHEAST WILL ACT AS A
FOCUS FOR MAINLY AFTERNOON SHOWERS/STORMS. FLORIDA MAY SEE A
FAIRLY RAINY PERIOD AS WELL SHOULD A TROPICAL WAVE MOVE INTO THE
REGION LATER IN THE WEEK. WITH THE UPPER HIGH CENTERED OVER THE
MID-CONTINENT, CLOCKWISE FLOW WILL CONTINUE TO BRING IN MONSOONAL
MOISTURE TO THE FOUR CORNERS REGION. THIS WILL KEEP MAX
TEMPERATURES NEAR TO BELOW AVERAGE.


FRACASSO

$$





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