Prognostic Meteorological Discussion
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FXUS21 KWNC 171835
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 17 2014

SYNOPSIS: AT THE START OF THE HAZARDS OUTLOOK, SEVERAL WEAK WEATHER
DISTURBANCES ARE FORECAST TO MOVE ACROSS THE CONTIGUOUS U.S. BY THE MIDDLE OF
THE OUTLOOK PERIOD, A MORE SIGNIFICANT STORM SYSTEM IS PREDICTED TO DEVELOP
OVER THE CENTRAL PORTION OF THE COUNTRY. SEVERAL NORTHERN PACIFIC STORM SYSTEMS
ARE ANTICIPATED TO INFLUENCE THE SOUTHERN COASTAL AREAS OF ALASKA.

HAZARDS

HEAVY RAIN ALONG THE MAINE COAST, TUE-WED, APR 22-23.

HEAVY RAIN FOR THE NORTH-CENTRAL MISSISSIPPI VALLEY AND ADJACENT PARTS OF THE
PLAINS, TUE-WED, APR 22-23.

HEAVY RAIN FOR CENTRAL MONTANA, TUE-WED, APR 22-23.

FLOODING IS OCCURRING OR IMMINENT FOR THE CENTRAL GULF COAST STATES AND
NORTHERN PARTS OF FLORIDA, LOWER MICHIGAN, PARTS OF NEW YORK AND NEW ENGLAND,
AND OVER NORTHEASTERN NORTH DAKOTA AND ADJACENT NORTHWESTERN MINNESOTA (THE RED
RIVER OF THE NORTH), SUN-MON, APR 20-21.

FLOODING IS EITHER POSSIBLE OR LIKELY IN DIFFERENT PARTS OF NEW ENGLAND,
SUN-MON, APR 20-21.

HIGH WINDS ARE PREDICTED FOR MUCH OF NEVADA, SOUTHWEST UTAH, ARIZONA AND NEW
MEXICO, MON-WED, APR 21-23.

SEVERE DROUGHT FOR PARTS OF IOWA, GREAT PLAINS, SOUTHWEST, PACIFIC NORTHWEST,
GREAT BASIN, CALIFORNIA, AND HAWAII.

DETAILED SUMMARY

FOR SUNDAY APRIL 20 - THURSDAY APRIL 24: HEAVY RAIN (1.5 INCHES) IS PREDICTED
ALONG THE MAINE COAST EARLY IN THE PERIOD, IN ASSOCIATION WITH AN OFFSHORE
FRONTAL SYSTEM. MOST OF THE RAIN ACCOMPANYING THIS SYSTEM IS FORECAST TO REMAIN
OFF THE NEW ENGLAND COAST.



THERE ARE A SIGNIFICANT NUMBER OF FLOOD-RELATED DESIGNATIONS ON THE MAP IN THE
EAST. THESE ARE GENERALLY DUE TO WET ANTECEDENT CONDITIONS, ANTICIPATED
RAINFALL DURING (OR IN THE TWO DAYS PRIOR TO) THIS PERIOD, OR SNOW MELT (IN
NORTHERN AREAS).



BY THE MIDDLE OF THIS PERIOD, A SIGNIFICANT 500-HPA TROUGH IS PREDICTED BY MOST
MODELS TO MOVE ACROSS THE WESTERN CONUS. HIGH WINDS (20-30 KTS OR MORE) ARE
FORECAST FOR NEVADA, SOUTHWEST UTAH, ARIZONA AND NEW MEXICO, IN CONNECTION WITH
THIS TROUGH. NO SPECIFIC WILDFIRE AREAS ARE DESIGNATED ON THE MAP AGAIN TODAY,
BECAUSE OF SIGNIFICANT MODEL DIFFERENCES IN THE TIMING OF INDIVIDUAL SHORT
WAVES EMBEDDED WITHIN THE LONG WAVE TROUGH. HOWEVER, THE SITUATION OVER THE
SOUTHWEST WILL NEED TO BE MONITORED FOR ANY CHANGES. AS THIS PREDICTED TROUGH
MOVES OUT INTO THE PLAINS, THERE IS ALSO THE POTENTIAL FOR STRONG TO SEVERE
THUNDERSTORMS TO DEVELOP. HOWEVER, THE LATEST GUIDANCE SUGGESTS THAT ANY STORMS
THAT DO FORM COULD BE LIMITED BY THE AMOUNT OF UNSTABLE, LOW-LEVEL GULF
MOISTURE AVAILABLE TO THEM. FOR NOW, NO SEVERE WEATHER AREA HAS BEEN
HIGHLIGHTED ON THE MAP. SEVERAL FAIRLY LOCALIZED AREAS OF HEAVY RAIN ARE
EXPECTED IN CENTRAL MONTANA AND THE NORTH-CENTRAL MISSISSIPPI VALLEY,
ASSOCIATED WITH THE SURFACE LOW PRESSURE SYSTEM THAT IS EXPECTED TO DEVELOP ON
THE EASTERN SIDE OF THE 500-HPA TROUGH.



DURING THE LATTER HALF OF THIS PERIOD, ABOVE-NORMAL TEMPERATURES ARE BRIEFLY
PREDICTED OVER THE GREAT PLAINS, IN ADVANCE OF THE ANTICIPATED 500-HPA TROUGH.
DAYTIME TEMPERATURES ARE FORECAST TO BE 16-20 DEGREES ABOVE-NORMAL IN KANSAS
AND NEBRASKA, WHICH TRANSLATES INTO HIGHS IN THE 80`S. HOWEVER, THIS IS NOT
CONSIDERED HAZARDOUS.



IN THE NORTHWEST, 1.0-1.5 INCHES OF RAIN ARE ANTICIPATED LATER IN THIS PERIOD,
THOUGH THIS TOO IS NOT CONSIDERED HAZARDOUS.



SEVERAL LOW PRESSURE SYSTEMS ARE FORECAST TO MOVE ACROSS THE ALEUTIANS AND GULF
OF ALASKA, BRINGING PRECIPITATION TO MUCH OF THE SOUTHERN ALASKA COAST,
ESPECIALLY THE PANHANDLE. AT THIS TIME, NO HAZARDS ARE DEPICTED FOR THE STATE.

FOR FRIDAY APRIL 25 - THURSDAY MAY 01: BY WEEK-2, THE GENERAL CIRCULATION
PATTERN AT 500-HPA IS EXPECTED TO FEATURE A FAST, WESTERLY JET ACROSS THE
NORTHERN PACIFIC, WHICH WILL DIRECT ABUNDANT MOISTURE INTO THE PACIFIC
NORTHWEST. A RIDGE IS ANTICIPATED OVER THE PLAINS, WHILE FAST, LOW AMPLITUDE
FLOW IS PREDICTED OVER THE EAST. NO SPECIFIC HAZARDS CAN BE DESIGNATED WITH
CONFIDENCE AT THIS RANGE, OTHER THAN CONTINUING LONG-TERM DROUGHT AREAS.



ACCORDING TO THE U.S. DROUGHT MONITOR VALID ON APRIL 15, SEVERE DROUGHT
COVERAGE HAS INCREASED NEARLY A PERCENTAGE POINT, FROM 24.23 PERCENT LAST WEEK
(CONUS) TO 25.20 PERCENT THIS WEEK.

FORECASTER: ANTHONY ARTUSA

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