Prognostic Meteorological Discussion
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FXUS21 KWNC 301950
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 30 2015

SYNOPSIS: A STATIONARY FRONT IS FORECAST NEAR THE GULF COAST THIS WEEKEND, WITH
THE POTENTIAL FOR SURFACE LOW DEVELOPMENT ACROSS THE NORTHEAST GULF OF MEXICO.
AN AREA OF UPPER-LEVEL LOW PRESSURE NORTH OF THE GREAT LAKES IS EXPECTED TO
RESULT IN A COLD FRONT PROGRESSING SOUTHEAST FROM THE UPPER MISSISSIPPI VALLEY
TO THE NORTHEAST NEXT WEEK. UPPER-LEVEL HIGH PRESSURE IS FORECAST TO WEAKEN
ACROSS THE PACIFIC NORTHWEST FOLLOWING THE WEEKEND. UPPER-LEVEL HIGH PRESSURE
IS EXPECTED TO RETURN TO MAINLAND ALASKA BY EARLY NEXT WEEK.

HAZARDS

HEAVY RAIN ACROSS PARTS OF NORTHERN FLORIDA, SUN-WED, AUG 2-5.

MUCH ABOVE-NORMAL TEMPERATURES FOR PARTS OF THE PACIFIC NORTHWEST, SUN, AUG 2.

ONGOING FLOODING ACROSS PARTS OF THE MIDDLE AND LOWER MISSISSIPPI VALLEY.

SEVERE DROUGHT FOR PARTS OF THE WESTERN THIRD OF THE CONUS, SOUTHERN GEORGIA,
SOUTHERN FLORIDA, NORTH CAROLINA AND HAWAII.

DETAILED SUMMARY

FOR SUNDAY AUGUST 02 - THURSDAY AUGUST 06: A STATIONARY FRONT, WITH THE
POTENTIAL FOR AN ASSOCIATED SURFACE LOW,  IS EXPECTED TO BE THE FOCUS FOR HEAVY
RAINFALL FROM THE FLORIDA PANHANDLE NORTHEAST JUST OFFSHORE THE OUTER BANKS.
BECAUSE THIS FRONT IS PREDICTED TO BE SLOW-MOVING, THE THREAT FOR HEAVY RAIN
EXTENDS FROM SUNDAY, THE 2ND THROUGH WEDNESDAY, THE 5TH IN PARTS OF NORTHERN
FLORIDA, WITH RAINFALL TOTALS OF MORE THAN 5 INCHES POSSIBLE IN THIS AREA.



THE POSITION OF THE UPPER-LEVEL RIDGE FAVORS A MODERATE MONSOON FLOW ACROSS THE
SOUTHWEST. THE HEAVIEST RAINFALL (LOCALLY MORE THAN 0.5 INCH WITH INDIVIDUAL
THUNDERSTORMS) IS EXPECTED ACROSS THE HIGHER TERRAIN OF SOUTHERN COLORADO AND
NORTHERN NEW MEXICO. THE HIGHEST RISK OF FLASH FLOODING ACROSS THESE AREAS IS
EXPECTED PRIOR TO THE OUTLOOK PERIOD WHEN RAINFALL AMOUNTS ARE ENHANCED DUE TO
UPSLOPE FLOW.



AN AMPLIFIED UPPER-LEVEL RIDGE IS EXPECTED TO MAINTAIN UNSEASONABLY HOT
TEMPERATURES ACROSS PARTS OF THE PACIFIC NORTHWEST DURING SUNDAY. MUCH
ABOVE-NORMAL TEMPERATURES ARE POSTED FOR AREAS WHERE MAXIMUM TEMPERATURES ARE
FORECAST TO AVERAGE 12 DEGREES F OR MORE ABOVE-NORMAL. MAXIMUM TEMPERATURES ARE
FORECAST TO MODERATE EARLY NEXT WEEK AS 500-HPA HEIGHTS DECREASE.



FOLLOWING A RECENT WET PERIOD, AN INCREASE IN 500-HPA HEIGHTS DURING THE
WEEKEND IS EXPECTED TO RESULT IN A DRYING TREND AND WARMER TEMPERATURES ACROSS
INTERIOR ALASKA. ACCORDING TO THE ALASKA INTERAGENCY COORDINATION CENTER ON
JULY 28, NEARLY 5 MILLION ACRES HAVE BEEN CONSUMED BY WILDFIRES THIS SEASON.
THIS IS IN COMPARISON TO THE YEAR 2004, THE MOST ACTIVE ALASKA WILDFIRE SEASON
ON RECORD (DATING BACK TO 1950), WHEN 6.5 MILLION ACRES BURNED.



TROPICAL STORM GUILLERMO RECENTLY FORMED 1000 MILES OFF THE BAJA CALIFORNIA
COAST.  THIS SYSTEM SHOULD BE MONITORED AS IT COULD APPROACH HAWAII NEXT WEEK.

FOR FRIDAY AUGUST 07 - THURSDAY AUGUST 13: DURING WEEK-2, THE GFS AND ECMWF
ENSEMBLE MEANS INDICATE A DEAMPLIFICATION OF THE UPPER-LEVEL FLOW PATTERN, WITH
TROUGHS CENTERED NEAR BOTH COASTS. THIS PATTERN WOULD LIMIT THE POTENTIAL FOR
TEMPERATURE HAZARDS, AND FOCUS ANY PRECIPITATION ON THE PLAINS AND THE EAST
COAST. A RELATIVELY DRY, WARM PATTERN IS EXPECTED TO PERSIST ACROSS MUCH OF
ALASKA.



THE MOST RECENT U.S. WEEKLY DROUGHT MONITOR, RELEASED JULY 30, INDICATES A
SLIGHT INCREASE (FROM 16.74 TO 17.17) IN THE PERCENTAGE OF THE CONUS IN SEVERE
TO EXCEPTIONAL DROUGHT (D2-D4) FROM THE PREVIOUS WEEK.

FORECASTER: KENNETH PELMAN

$$



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