Prognostic Meteorological Discussion
Issued by NWS

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FXUS21 KWNC 272256
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 27 2015

SYNOPSIS: AT THE START OF THE PERIOD, A FRONTAL SYSTEM IS EXPECTED TO EXTEND
SOUTHWESTWARD

FROM THE GREAT LAKES ACROSS THE MIDDLE MISSISSIPPI VALLEY TO THE SOUTHERN
PLAINS.

THE FRONT IS FORECAST TO MOVE SLOWLY SOUTHEASTWARD BEFORE STALLING AND THEN

MOVING BACK NORTHEASTWARD AS A WARM FRONT. SURFACE LOW PRESSURE OVER THE
NORTHERN

ROCKIES ON MAY 30 IS ANTICIPATED TO MOVE SLOWLY EASTWARD TO THE NORTHERN PLAINS

BY JUN 2. SURFACE LOW PRESSURE EXPECTED OVER SOUTHEASTERN ALASKA ON MAY 30 IS

EXPECTED TO MOVE VERY LITTLE THROUGH JUN 2. AN AREA OF DISTURBED WEATHER SOUTH
OF

THE MEXICAN COAST IS FORECAST TO TRACK TOWARDS THE WEST-NORTHWEST.



HAZARDS

HEAVY RAIN FOR PARTS OF THE MIDDLE MISSISSIPPI AND OHIO VALLEYS, GREAT LAKES,

CENTRAL APPALACHIANS, MID-ATLANTIC, AND NORTHEAST, SAT-SUN, MAY 30-31.

HEAVY RAIN FOR PARTS OF THE NORTHERN ROCKIES AND NORTHERN PLAINS, MON-TUE, JUN

1-2.

ENHANCED WILDFIRE RISK FOR INTERIOR EASTERN ALASKA, SAT-WED, MAY 30-JUN 3.

FLOODING IS POSSIBLE, IMMINENT, OR OCCURRING ACROSS PORTIONS OF THE CENTRAL AND

WEST-CENTRAL CONUS.

SEVERE DROUGHT FOR PARTS OF THE NORTHERN, CENTRAL, AND SOUTHERN GREAT PLAINS,

SOUTHWEST, GREAT BASIN, CALIFORNIA, AND THE PACIFIC NORTHWEST.

DETAILED SUMMARY

FOR SATURDAY MAY 30 - WEDNESDAY JUNE 03: AN UPPER-LEVEL RIDGE IS EXPECTED TO
LEAD TO VERY WARM DAILY MAXIMUM TEMPERATURES

(POSITIVE ANOMALIES OF 10-15 DEGREES F) FOR PARTS OF THE NORTHWESTERN CONUS MAY

30-31. WHILE SOME LOCATIONS MAY APPROACH 90 DEGREES F, A HAZARD SHAPE IS NOT

DEEMED WARRANTED.



AT THE START OF THE PERIOD A FRONTAL SYSTEM IS FORECAST TO STRETCH
SOUTHWESTWARD

FROM THE GREAT LAKES ACROSS THE MIDDLE MISSISSIPPI VALLEY TO THE SOUTHERN

PLAINS. AS THE FRONT MOVES SLOWLY SOUTHEASTWARD IT IS EXPECTED TO ACT AS A

FOCUSING MECHANISM FOR SHOWERS AND THUNDERSTORMS. HEAVY RAIN (IN EXCESS OF 1

INCH IN 24 HOURS) IS EXPECTED FOR PARTS OF THE MIDDLE MISSISSIPPI AND OHIO

VALLEYS, GREAT LAKES, CENTRAL APPALACHIANS, MID-ATLANTIC, AND NORTHEAST MAY 30-

31. THUNDERSTORMS ARE LIKLEY DURING THE PERIOD OVER THESE REGIONS BUT MODEL

UNCERTAINTY PRECLUDES THE SPECIFICATION OF A SEVERE WEATHER HAZARD AT THE

CURRENT TIME.



LOW PRESSURE MOVING ACROSS THE NORTHERN ROCKIES LEADS TO HEAVY RAIN (IN EXCESS

OF 1 INCH IN 24 HOURS) FOR PARTS OF THE REGION JUNE 1-2.



IN THE EASTERN INTERIOR OF ALASKA, CONTINUED WARM, DRY, AND BREEZY CONDITIONS

FAVOR A SIGNIFICANTLY INCREASED CHANCE OF CRITICAL WILDFIRE CONDITIONS

THROUGHOUT THIS PERIOD.



NUMEROUS AREAS OF POSSIBLE, LIKELY, IMMINENT, AND OCCURRING FLOODING ARE

INDICATED OVER THE CENTRAL AND WEST-CENTRAL PORTIONS OF THE CONUS, WITH ALL THE

HEAVY RAIN RECEIVED IN RECENT DAYS AND WEEKS. TO OBTAIN THE VERY LATEST,

DETAILED INFORMATION ON THE STATUS OF STREAMS AND RIVERS ACROSS THE U.S.,
PLEASE

CONSULT THE RIVER FORECAST CENTER (RFC) HOMEPAGE AT:

HTTP://WATER.WEATHER.GOV/AHPS/RFC/RFC.PHP.

FOR THURSDAY JUNE 04 - WEDNESDAY JUNE 10: THE EXPECTED MID-TROPOSPHERIC FLOW
PATTERN FOR WEEK-2 FEATURES BASICALLY ZONAL

FLOW ACROSS THE NORTHERN HALF OF THE CONUS. SIGNIFICANT POSITIVE HEIGHT

ANOMALIES AT 500-HPA (RANGING FROM +60 TO +100 METERS) ARE FORECAST ACROSS THE

NORTHEAST, AND ARE EXPECTED TO COINCIDE WITH ABOVE NORMAL SURFACE TEMPERATURES

DURING THIS PERIOD FOR THAT REGION.



THE MOST RECENT U.S. DROUGHT MONITOR, RELEASED MAY 21ST, INDICATES A
SUBSTANTIAL

DECREASE (FROM 17.68 TO 15.16) IN THE PERCENTAGE OF THE CONUS IN SEVERE TO

EXCEPTIONAL DROUGHT (D2-D4).

FORECASTER: RANDY SCHECHTER

$$



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