Prognostic Meteorological Discussion
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FXUS21 KWNC 221854
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SEPTEMBER 22 2014

SYNOPSIS: HIGH PRESSURE IS EXPECTED TO DOMINATE MOST OF THE EASTERN U.S. THE
ONE EXCEPTION IS 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 HIGH PRESSURE OVER THE WESTERN U.S. IS
EXPECTED TO BE REPLACED BY SURFACE AND UPPER-LEVEL LOW PRESSURE. LOW PRESSURE
SOUTH OF THE ALEUTIANS IS FORECAST TO MOVE TOWARDS THE GULF OF ALASKA AND
ALASKA PANHANDLE.

HAZARDS

FLOODING POSSIBLE FOR PARTS OF SOUTHEASTERN NEW MEXICO AND AND SOUTHWESTERN
TEXAS.

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

HEAVY RAIN ALONG THE 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 THURSDAY SEPTEMBER 25 - MONDAY SEPTEMBER 29: A STATIONARY FRONT DRAPED
ACROSS THE GULF OF MEXICO AND JUST OFF THE SOUTHEAST COAST 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. LOW PRESSURE IS FORECAST
TO FORM ALONG THE FRONT AND LEAD TO HEAVY RAIN (1-2 INCHES) FOR PARTS OF THE
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 SAT-SUN. LOCALLY HEAVY RAIN
(WITH SNOW AT THE HIGHEST ELEVATIONS) IS POSSIBLE, BUT MODEL UNCERTAINTY
PRECLUDES THE SPECIFICATION OF A HAZARD AREA AT THE CURRENT TIME.



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 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.



ANTECEDENT RAINFALL LEADS TO THE POSSIBILITY OF FLOODING FOR PARTS OF THE PECOS
RIVER IN SOUTHEASTERN NEW MEXICO AND SOUTHWESTERN TEXAS THU-FRI, ESPECIALLY
NEAR THE RED BLUFF RESERVOIR.



AN UPPER-LEVEL RIDGE IS EXPECTED TO RESULT IN MAXIMUM TEMPERATURES AVERAGING
AROUND 16-20 DEGREES F ABOVE-NORMAL ACROSS CENTRAL AND EASTERN MONTANA ON
THURSDAY. 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 TUESDAY SEPTEMBER 30 - MONDAY OCTOBER 06: A LOW AMPLITUDE FLOW PATTERN IS
EXPECTED TO DOMINATE THE CONUS DURING WEEK-2. A WEAK TROUGH IS ANTICIPATED OVER
THE WEST-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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