Prognostic Meteorological Discussion
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FXUS21 KWNC 291752
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 29 2016

SYNOPSIS: AT THE START OF THE PERIOD, A STATIONARY FRONT IS FORECAST FROM THE
MID-ATLANTIC TO THE NORTHERN GREAT PLAINS. THE EASTERN END OF THAT FRONT IS
FORECAST TO SAG SOUTHWARD OVER THE SOUTHEAST AS HIGH PRESSURE BUILDS IN OVER
THE NORTHEAST. AN UPPER-LEVEL LOW-PRESSURE SYSTEM IS FORECAST TO MOVE ACROSS
THE ROCKIES, AND CONTRIBUTE TO THE DEVELOPMENT OF A SURFACE LOW-PRESSURE OVER
SOUTHERN CANADA, WITH A COLD FRONT EXTENDING TO THE CENTRAL GREAT PLAINS. A
COLD FRONT IS FORECAST TO MOVE ACROSS NORTHERN ALASKA DURING THE EARLY PORTION
OF NEXT WEEK, WITH HIGH PRESSURE QUICKLY BUILDING IN BEHIND THAT. THERE IS A
RELATIVELY INCREASED THREAT OF A TROPICAL DEPRESSION DEVELOPING OVER THE
CENTRAL ATLANTIC OCEAN DURING THE NEXT 5 DAYS.

HAZARDS

HEAVY RAIN ACROSS PORTIONS OF THE SOUTHEAST AND THE MID-ATLANTIC, MON-TUE, AUG
1-AUG 2.

HIGH WINDS ACROSS PORTIONS OF MAINLAND ALASKA, MON, AUG 1.

SLIGHT RISK OF MUCH ABOVE-NORMAL TEMPERATURES FOR PORTIONS OF THE MID-ATLANTIC,
THE NORTHEAST, THE CENTRAL APPALACHIANS, THE LOWER MISSISSIPPI VALLEY, THE
SOUTHEAST, AND THE SOUTHERN PLAINS, SAT-SUN, AUG 6-AUG 7.

SEVERE DROUGHT ACROSS THE MID-ATLANTIC, THE LOWER MISSISSIPPI VALLEY, THE
CENTRAL GREAT BASIN, THE NORTHERN PLAINS, THE TENNESSEE VALLEY, THE GREAT
LAKES, HAWAII, THE NORTHEAST, CALIFORNIA, THE SOUTHERN APPALACHIANS, THE
SOUTHEAST, THE CENTRAL APPALACHIANS, THE SOUTHERN PLAINS, AND THE SOUTHWEST.

DETAILED SUMMARY

FOR MONDAY AUGUST 01 - FRIDAY AUGUST 05: HEAVY RAINFALL (EXCEEDING 1" IN 24
HOURS) IS FORECAST FOR SOUTHEASTERN VIRGINIA AND THE EASTERN CAROLINAS ON
AUGUST 1 ASSOCIATED WITH A COLD FRONT EXPECTED TO SLOWLY DESCEND THROUGH THE
REGION. HEAVY RAINS ARE EXPECTED TO MOVE FROM NORTH TO SOUTH ACROSS THE
HIGHLIGHTED REGION.



A COLD FRONT ASSOCIATED WITH A LOW-PRESSURE SYSTEM FORECAST TO DEVELOP OVER
SOUTHERN CANADA IS LIKELY TO SUPPORT MODERATE TO LOCALLY HEAVY RAINS OVER THE
NORTHERN AND CENTRAL GREAT PLAINS, WITH THE POTENTIAL FOR HEAVY RAINS TO MOVE
EASTWARD TO THE GREAT LAKES. ISOLATED SEVERE WEATHER IS POSSIBLE OVER THE
DAKOTAS ON TUE, AUG 2, AND AGAIN ON THU, AUG 4, WITH THE SECOND ROUND
ASSOCIATED WITH A SLIGHTLY STRONGER VORTICITY MAXIMA AT 500 MB.



MULTIPLE MODERATE RAIN EVENTS (WITH LOCALIZED HEAVIER RAIN ON FAVORABLY
ORIENTED TERRAIN) COULD LEAD TO FLOODING CONCERNS. FLOOD WATCHES HAVE BEEN
ISSUED FOR THE SEWARD PENINSULA AND WESTERN INTERIOR OF ALASKA THAT CURRENTLY
END PRIOR TO DAY 3, BUT MAY BE EXTENDED INTO THE FORECAST PERIOD. ASSOCIATED
WITH THE FRONTAL PASSAGE IS THE LIKELIHOOD OF HIGH WINDS, ESPECIALLY ACROSS THE
HIGHER TERRAIN OF NORTHERN ALASKA.



ENHANCED ODDS FOR HIGH WINDS, LOW RH, AND ELEVATED TEMPERATURES ARE INDICATED
BY THE STORM PREDICTION CENTER OVER PORTIONS OF THE GREAT BASIN, NORTHWEST, AND
NORTHERN ROCKIES DURING THE EARLY PORTIONS OF NEXT WEEK. THESE CONDITIONS ARE
FORECAST TO ACCOMPANY THE UPPER-LEVEL TROUGH THAT LATER NEXT WEEK CONTRIBUTES
TO THE LOW-PRESSURE DEVELOPMENT OVER SOUTHERN CANADA.





FOR SATURDAY AUGUST 06 - FRIDAY AUGUST 12: THE 500-HPA PATTERN AT THE BEGINNING
OF WEEK-2 IS FORECAST TO FEATURE RIDGING ALONG THE ROCKIES, WITH TROUGHS NEAR
THE WEST COAST AND OVER NEW ENGLAND. AS THE WEEK PROGRESSES, DYNAMICAL MODEL
ENSEMBLE GUIDANCE SUPPORTS 500-HPA TROUGHING DEEPENING ACROSS THE NORTHEAST AND
MODEST AMPLIFICATION OF A RIDGE FOCUSED OVER THE ROCKIES AND CENTRAL CONUS.



TWO AREAS ARE HIGHLIGHTED FOR A SLIGHT RISK OF MUCH ABOVE-NORMAL TEMPERATURES
DURING WEEK-2.  THE FIRST REGION EXTENDS FROM THE NORTHEAST TO THE CAROLINAS,
COINCIDING WITH HIGH PRESSURE AHEAD OF THE COLD FRONT FORECAST TO MOVE ACROSS
THE GREAT PLAINS DURING NEXT WEEK. THE SECOND REGION IS OVER TEXAS AND THE GULF
COAST, WHERE SUBTROPICAL RIDGING IS FORECAST TO PERSIST INTO NEXT WEEKEND. BOTH
AREAS ARE FORECAST TO RELAX AS THE 8-14 DAY PERIOD PROGRESSES.



THE NATIONAL HURRICANE CENTER HAS HIGHLIGHTED TWO AREAS FOR POTENTIAL
DEVELOPMENT OF A TROPICAL CYCLONE DURING THE NEXT 5 DAYS. SOME SOLUTIONS FROM
THE GEFS TAKE THE WESTERNMOST SYSTEM ACROSS THE CARIBBEAN, INDICATING A
POTENTIAL THREAT FOR IMPACTS TO PUERTO RICO AT DAY 4 (AUG 2-3). ADDITIONAL
INFORMATION ON THESE SYSTEMS ARE AVAILABLE THROUGH THE NHC
(HTTP://WWW.NHC.NOAA.GOV) OR GLOBAL TROPICAL HAZARDS OUTLOOK
(HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PRECIP/CWLINK/GHAZARDS/INDEX.PHP).



ACCORDING TO THE U.S. DROUGHT MONITOR (USDM), RELEASED ON JULY 28, SEVERE, OR
GREATER INTENSITY DROUGHT COVERS 5.97 PERCENT OF THE U.S. DROUGHT MONITOR AREAS
(INCLUDING ALASKA, HAWAII, AND PUERTO RICO).  THIS IS A NEARLY THREE-TENTHS OF
A PERCENT INCREASE COMPARED TO THE PRIOR WEEK.  THIS INCREASE IS DUE TO AN
EXPANSION OF SHORT-TERM SEVERE DROUGHT ACROSS THE EASTERN CONUS, PRIMARILY
ACROSS THE LOWER-MISSISSIPPI VALLEY.

FORECASTER: MATTHEW ROSENCRANS

$$



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