Prognostic Meteorological Discussion
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FXUS21 KWNC 231857
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SEPTEMBER 23 2014

SYNOPSIS: HIGH PRESSURE IS EXPECTED TO DOMINATE MOST OF THE EASTERN U.S. THE
ONE EXCEPTION IS OFF THE SOUTHEAST COAST AND ALONG THE GULF COAST WHERE A
STATIONARY FRONT AND EASTERLY FLOW AROUND THE AREA OF HIGH PRESSURE ARE
ANTICIPATED TO LEAD TO UNSETTLED WEATHER. BY MID-PERIOD, AN AREA OF LOW
PRESSURE IS FORECAST TO FORM ALONG THE FRONT. EARLY IN THE PERIOD, UPPER-LEVEL
LOW PRESSURE ALONG THE WEST COAST IS EXPECTED TO MOVE INLAND TO THE CENTRAL
GREAT BASIN. LOW PRESSURE SOUTH OF THE ALEUTIANS IS FORECAST TO MOVE TOWARDS
THE GULF OF ALASKA AND ALASKA PANHANDLE.

HAZARDS

HEAVY RAIN FOR PARTS OF THE ALASKA PANHANDLE, FRI-SAT, SEP 26-27.

HEAVY RAIN FOR PARTS OF THE CENTRAL GREAT BASIN AND NORTHERN INTERMOUNTAIN
WEST, SAT, SEP 27.

HEAVY RAIN FOR PARTS OF SOUTHWESTERN UTAH, SAT, SEP 27.

HEAVY RAIN ALONG PARTS OF THE CENTRAL AND EASTERN GULF COAST, SAT-SUN, SEP
27-28.

SEVERE DROUGHT FOR THE CENTRAL AND SOUTHERN GREAT PLAINS, SOUTHWEST, SOUTHERN
GEORGIA, PACIFIC NORTHWEST, GREAT BASIN, AND CALIFORNIA.

DETAILED SUMMARY

FOR FRIDAY SEPTEMBER 26 - TUESDAY SEPTEMBER 30: A STATIONARY FRONT EXTENDING
FROM JUST OFF THE SOUTHEAST COAST AND ACROSS THE NORTHERN GULF OF MEXICO IS
FORECAST TO ACT AS A FOCUSING MECHANISM FOR SHOWERS AND THUNDERSTORMS. MOST OF
THE HEAVY PRECIPITATION IS EXPECTED TO REMAIN OFFSHORE BUT LOCALLY HEAVY RAIN
IS POSSIBLE ALONG SMALL PORTIONS OF THE SOUTHEAST AND GULF COASTS AND OVER THE
FLORIDA PENINSULA. LOW PRESSURE IS FORECAST TO FORM ALONG THE FRONT AND LEAD TO
HEAVY RAIN (1-2 INCHES) FOR PARTS OF THE CENTRAL AND EASTERN GULF COAST SAT-SUN.



LOW PRESSURE AT THE SURFACE AND ALOFT IS ANTICIPATED TO LEAD TO UNSETTLED
WEATHER FOR MUCH OF THE INTERIOR WESTERN CONUS SATURDAY. LOCALLY HEAVY RAIN
(1-2 INCHES IN A 24-HOUR PERIOD) IS EXPECTED OVER PARTS OF THE CENTRAL GREAT
BASIN AND NORTHERN INTERMOUNTAIN WEST. LOCALLY HEAVY RAIN (IN EXCESS OF 1 INCH)
IS ALSO EXPECTED ON SATURDAY FOR PARTS OF SOUTHWESTERN UTAH. THIS RAINFALL IS
OF CONCERN BECAUSE OF THE ANTECEDENT HEAVY RAIN SOME OF THESE AREAS EXPERIENCED
IN THE PAST 10 DAYS.



LOW PRESSURE SOUTH OF THE ALEUTIANS IS FORECAST TO MOVE INTO THE GULF OF
ALASKA. HEAVY RAIN (IN EXCESS OF 2 INCHES IN 24-HOURS) IS ANTICIPATED FOR PARTS
OF THE ALASKA PANHANDLE ON FRIDAY AND SATURDAY. UNSETTLED WEATHER IS EXPECTED
TO PERSIST FOR THE AREA, BUT MODEL UNCERTAINTY ON PRECIPITATION AMOUNTS DOES
NOT PERMIT EXTENDING THE HAZARD AREA BEYOND SATURDAY. LOW PRESSURE APPROACHING
THE NORTHWEST COAST OF ALASKA MAY LEAD TO SIGNIFICANT WAVES FOR THE REGION ON
MONDAY, BUT MODEL UNCERTAINTY PRECLUDES THE SPECIFICATION OF A HAZARD AREA AT
THE CURRENT TIME.



AN UPPER-LEVEL RIDGE IS EXPECTED TO RESULT IN MAXIMUM TEMPERATURES AVERAGING IN
EXCESS OF 20 DEGREES F ABOVE-NORMAL ACROSS PARTS OF THE NORTHERN PLAINS ON
FRIDAY. SINCE MAXIMUM TEMPERATURES ARE FORECAST TO REMAIN BELOW 90 DEGREES F
ACROSS THESE AREAS, A MUCH-ABOVE NORMAL TEMPERATURE HAZARD IS NOT DEEMED
NECESSARY.

FOR WEDNESDAY OCTOBER 01 - TUESDAY OCTOBER 07: A LOW AMPLITUDE FLOW PATTERN IS
EXPECTED TO DOMINATE MOST OF THE CONUS DURING WEEK-2. A WEAK TROUGH IS
ANTICIPATED OVER THE CENTRAL CONUS. OTHER THAN THE CONTINUATION OF LONG TERM
DROUGHT, NO HAZARD AREAS CAN RELIABLY BE SPECIFIED.



THE U.S. DROUGHT MONITOR, VALID ON SEPTEMBER 16, INDICATES THAT THE PERCENTAGE
OF THE CONUS IN SEVERE TO EXCEPTIONAL DROUGHT DECREASED BELOW 20 PERCENT FOR
THE FIRST TIME SINCE JANUARY 2014.

FORECASTER: RANDY SCHECHTER

$$




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