Prognostic Meteorological Discussion
Issued by NWS

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FXUS21 KWNC 251836
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 25 2016

SYNOPSIS: AT THE START OF THE PERIOD, A TROPICAL DISTURBANCE IS EXPECTED TO BE
NEAR SOUTHERN FLORIDA. THIS SYSTEM IS CURRENTLY ANTICIPATED TO DRIFT SLOWLY
WESTWARD INTO THE EASTERN GULF OF MEXICO THEN DRIFT NORTHWARD TOWARDS THE
EAST/CENTRAL GULF COAST AND THE SOUTHEAST U.S.. SURFACE HIGH PRESSURE OVER
MAINE ON AUG 28 IS FORECAST TO MOVE EASTWARD INTO THE NORTH ATLANTIC. AT THE
SAME TIME, A WARM FRONT IS EXPECTED TO MOVE NORTHWARD ACROSS THE NORTHERN
PLAINS. SURFACE LOW PRESSURE NEAR THE ALASKA PANHANDLE DURING THE PERIOD IS
FORECAST TO BRING UNSETTLED WEATHER TO THE REGION.

HAZARDS

HEAVY RAIN FOR PARTS OF SOUTHERN FLORIDA, SUN-MON, AUG 28-29.

HEAVY RAIN FOR PARTS OF THE SOUTHEAST, WED-THU, AUG 31-SEP 1.

MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN PLAINS, SUN-MON, AUG
28-29.

MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE OHIO VALLEY, GREAT LAKES,
NORTHEAST, AND CENTRAL APPALACHIANS, SUN AUG 28.

FLOODING POSSIBLE, OCCURRING OR IMMINENT ACROSS PORTIONS OF THE GREAT LAKES AND
THE MISSISSIPPI VALLEY.

SLIGHT CHANCE OF MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN AND
CENTRAL PLAINS, FRI, SEP 2.

SEVERE DROUGHT ACROSS PARTS OF THE EASTERN U.S., GREAT PLAINS, NORTHERN
ROCKIES, GREAT BASIN, ARIZONA, CALIFORNIA, EASTERN OREGON, AND HAWAII.

DETAILED SUMMARY

FOR SUNDAY AUGUST 28 - THURSDAY SEPTEMBER 01: EARLY IN THE PERIOD A TROPICAL
DISTURBANCE IS FORECAST TO APPROACH SOUTHERN FLORIDA. THE DISTURBANCE IS
EXPECTED TO DRIFT WESTWARD INTO THE EASTERN GULF OF MEXICO BY AUG 30, THEN
NORTHWARD TOWARDS THE EAST/CENTRAL GULF COAST BY SEP 1. THIS LEADS TO HEAVY
RAIN (IN EXCESS OF 1 INCH IN 24 HOURS) FOR PARTS OF SOUTHERN FLORIDA AUG 28-29,
AND FOR PARTS OF THE SOUTHEAST AUG 31-SEP 1. THE EXACT TRACK AND STRENGTH OF
THE TROPICAL DISTURBANCE ARE HIGHLY UNCERTAIN AT THIS TIME AND ADDITIONAL
IMPACTS (FLOODING, ISOLATED TORNADOES, HIGH WINDS, SIGNIFICANT WAVES, BEACH
EROSION ETC.) ARE POSSIBLE FOR PARTS OF THE SOUTHEAST AND GULF COAST. IN
ADDITION, PARTS OF LOUISIANA ARE CURRENTLY EXPERIENCING FLOODING SO THAT
ADDITIONAL HEAVY RAINFALL WOULD EXTEND AND EXACERBATE FLOODING CONCERNS,
ALTHOUGH THE HEAVIEST RAIN IS CURRENTLY EXPECTED TO FALL TO THE EAST OF WHERE
THE MOST SERIOUS FLOODING IS OCCURRING. PLEASE CONSULT THE LATEST ADVISORIES
FROM THE NATIONAL HURRICANE CENTER AT HTTP://WWW.NHC.NOAA.GOV/.



SOUTHERLY FLOW AROUND THE WEST SIDE OF HIGH PRESSURE CENTERED OVER THE
NORTHEAST LEADS TO MUCH ABOVE NORMAL TEMPERATURES (POSITIVE ANOMALIES OF 10-12
DEGREES F) FOR PARTS OF THE OHIO VALLEY, GREAT LAKES, NORTHEAST, AND CENTRAL
APPALACHIANS AUG 28.



AT THE START OF THE PERIOD A FRONTAL SYSTEM STRETCHING ACROSS MUCH OF THE
CENTRAL CONUS IS EXPECTED TO MOVE NORTHWARD AS A WARM FRONT. SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THIS SYSTEM ARE FORECAST OVER THE UPPER
MISSISSIPPI VALLEY ON AUG 28. RAINFALL AMOUNTS MAY BE LOCALLY HEAVY OVER
PORTIONS OF THESE REGIONS. MUCH ABOVE NORMAL TEMPERATURES (POSITIVE TEMPERATURE
ANOMALIES OF 10-15 DEGREES F) ARE ANTICIPATED FOR PARTS OF THE NORTHERN PLAINS
AUG 28-29.



ANTECEDENT RAINFALL, IN COMBINATION WITH ADDITIONAL RAINFALL EXPECTED DURING
THE PERIOD LEADS TO FLOODING POSSIBLE, IMMINENT, OR OCCURRING ACROSS PORTIONS
OF THE GREAT LAKES AND THE MISSISSIPPI VALLEY.



DESPITE DRY FUELS OVER MUCH OF THE WESTERN CONUS, WIND SPEEDS ARE FORECAST TO
LESSEN SO THAT CRITICAL FIRE WEATHER CONDITIONS ARE NOT CURRENTLY ANTICIPATED
EARLY IN THE PERIOD. LATER IN THE PERIOD, MODEL UNCERTAINTY IS TOO LARGE TO
SPECIFY A HAZARD SHAPE.

FOR FRIDAY SEPTEMBER 02 - THURSDAY SEPTEMBER 08: DURING WEEK-2 THE CIRCULATION
PATTERN IS EXPECTED TO FEATURE A TROUGH OVER THE WESTERN CONUS AND ZONAL FLOW
ACROSS MUCH OF THE NORTH-CENTRAL PART OF THE NATION. THIS CIRCULATION PATTERN
FAVORS BELOW NORMAL TEMPERATURES OVER THE WESTERN CONUS, AND A SLIGHT CHANCE OF
MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN AND CENTRAL PLAINS SEP
2.



THE TROPICAL DISTURBANCE CURRENTLY NORTH OF HAITI MAY BE IMPACTING PARTS OF THE
SOUTHEAST AND MID-ATLANTIC EARLY IN THE PERIOD BUT MODEL UNCERTAINTY PRECLUDES
THE SPECIFICATION OF HAZARD SHAPES AT THE CURRENT TIME. THE ATLANTIC IS SHOWING
INCREASED TROPICAL ACTIVITY AND THIS EVOLUTION WILL NEED TO BE MONITORED.
PLEASE CONSULT THE LATEST ADVISORIES FROM THE NATIONAL HURRICANE CENTER AT
HTTP://WWW.NHC.NOAA.GOV/.



ACCORDING TO THE U.S. DROUGHT MONITOR, THE COVERAGE OF SEVERE OR GREATER
DROUGHT DECREASED SLIGHTLY TO 7.41 PERCENT FROM 7.71 PERCENT. IMPROVEMENTS WERE
REALIZED ACROSS CENTRAL TEXAS AND THE TENNESSEE VALLEY.

FORECASTER: RANDY SCHECHTER

$$




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