Prognostic Meteorological Discussion
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FXUS21 KWNC 161837
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 16 2014

SYNOPSIS: AT THE START OF THE HAZARDS OUTLOOK, FRONTAL SYSTEMS ARE FORECAST
OVER THE PACIFIC NORTHWEST, THE MISSISSIPPI VALLEY/GREAT PLAINS REGION, AND
JUST OFF THE SOUTHERN ATLANTIC COAST. BY THE MIDDLE OF THE OUTLOOK PERIOD, A
SIGNIFICANT STORM SYSTEM IS PREDICTED TO DEVELOP OVER THE CENTRAL PORTION OF
THE CONTIGUOUS U.S. SEVERAL NORTHERN PACIFIC STORM SYSTEMS ARE ANTICIPATED TO
INFLUENCE THE SOUTHERN COASTAL AREAS OF ALASKA.

HAZARDS

HEAVY RAIN ALONG THE CAROLINA COAST, SAT-SUN, APR 19-20.

FLOODING IS OCCURRING OR IMMINENT OVER THE CENTRAL GULF COAST STATES, THE LOWER
OHIO VALLEY, LOWER MICHIGAN, NORTHERN NEW YORK, AND OVER NORTHEASTERN NORTH
DAKOTA AND ADJACENT NORTHWESTERN MINNESOTA (THE RED RIVER OF THE NORTH),
SAT-SUN, APR 19-20.

FLOODING IS LIKELY IN NORTHERN NEW YORK AND WESTERN NEW ENGLAND, SAT-SUN, APR
19-20.

FLOODING IS POSSIBLE IN THE MIDWEST, EASTERN NEW YORK, NEW ENGLAND, AND THE
CENTRAL PART OF THE FLORIDA PANHANDLE, SAT-SUN, APR 19-20.

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

DETAILED SUMMARY

FOR SATURDAY APRIL 19 - WEDNESDAY APRIL 23: HEAVY RAIN (2 INCHES) IS PREDICTED
ALONG THE CAROLINA 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 SOUTHERN ATLANTIC 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). UP TO NOW, COLDER WEATHER HAS PREVENTED RAPID SNOW MELT, WHICH
WOULD OTHERWISE RESULT IN SIGNIFICANT FLOODING. HOWEVER, THIS IS OFFSET
SOMEWHAT BY FROST DEPTHS OF 3.5 - 5.0 FEET IN PARTS OF THE UPPER MIDWEST, WHICH
PREVENTS MELT WATER FROM PERCOLATING DEEP INTO THE SOIL, AND RESULTS IN
INCREASED RUNOFF. FOR MORE INFORMATION, PLEASE REFER TO THE NORTH CENTRAL RIVER
FORECAST CENTER SITE:
HTTP://WWW.CRH.NOAA.GOV/NCRFC/CONTENT/SOILTEMP/SOILTEMP_GD.PHP?PE=OB&DEPTH=02



TOWARDS THE END OF THIS PERIOD, A SIGNIFICANT 500-HPA TROUGH IS PREDICTED BY
MOST MODELS TO MOVE ACROSS THE WESTERN CONUS. THOUGH THE DETAILS REGARDING
EMBEDDED SHORT-WAVE ENERGY REMAIN UNCLEAR AT THIS TIME, THIS PATTERN IN APRIL
SUGGESTS THE POSSIBILITY FOR AN ELEVATED WILDFIRE RISK IN THE SOUTHWEST, AND
SEVERE WEATHER ACROSS THE CENTRAL STATES. PENDING FUTURE MODEL TRENDS,
HAZARDOUS AREAS MAY NEED TO BE DESIGNATED ON THE MAP ON THURSDAY OR FRIDAY IN
THIS AREAS.



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 THURSDAY APRIL 24 - WEDNESDAY APRIL 30: BY WEEK-2, MOST MODELS FAVOR A
TROUGH OVER THE SOUTHWEST, AND A WEAK RIDGE OVER THE EAST-CENTRAL CONUS. AS
WITH THE EARLIER 3-7 DAY PERIOD, THE POTENTIAL FOR BOTH ELEVATED WILDFIRE
CONDITIONS (SOUTHWEST) AND SEVERE WEATHER (CENTRAL STATES) WILL NEED TO BE
WATCHED, ESPECIALLY EARLY IN THE PERIOD. IN ADDITION, IF MOST MODELS ARE
CORRECT IN PREDICTING THE TRANSPORT OF LOW-LEVEL GULF MOISTURE INTO THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY, IT MAY REQUIRE THE EXTENSION
AND/OR EXPANSION OF THE FLOOD HAZARDS IN THAT REGION. FOR NOW, THE ONLY HAZARDS
ANTICIPATED WITH CONFIDENCE ARE THE LONG-TERM DROUGHT AREAS.



ACCORDING TO THE U.S. DROUGHT MONITOR VALID ON APRIL 8, SEVERE DROUGHT COVERS
24.2 PERCENT OF THE CONUS, WHICH IS A MINOR INCREASE SINCE THE PREVIOUS WEEK
AND THE LARGEST COVERAGE SINCE SEPTEMBER 2013. THE U.S. DROUGHT MONITOR WILL BE
UPDATED TOMORROW MORNING AT 8:30 AM EASTERN TIME.

FORECASTER: ANTHONY ARTUSA

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