Prognostic Meteorological Discussion
Issued by NWS

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FXUS21 KWNC 011900
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 01 2015

SYNOPSIS: A COLD FRONT IS PREDICTED TO SINK EASTWARD AND SOUTHEASTWARD FROM THE
NORTHERN PLAINS INTO THE NORTHEASTERN QUARTER OF THE LOWER 48 STATES DURING THE
3-7 DAY PERIOD. MEANWHILE, A STATIONARY FRONT IS ANTICIPATED TO LINGER ACROSS
THE MIDDLE AND SOUTHERN ATLANTIC COASTS FOR MUCH OF THE 3-7 DAY PERIOD. SURFACE
LOW PRESSURE IS FORECAST TO DEVELOP ACROSS MUCH OF THE SOUTH COAST AND MAINLAND
ALASKA THURSDAY TO SATURDAY, FOLLOWED BY SURFACE LOW PRESSURE ACROSS THE
ALEUTIANS AND NORTHERN ALASKA SUNDAY TO MONDAY.

HAZARDS

HEAVY RAIN FOR PARTS OF THE UPPER AND MIDDLE MISSISSIPPI VALLEY, THU-FRI, JUN
4-5.

HEAVY RAIN FOR PARTS OF THE CENTRAL AND SOUTHERN APPALACHIANS, MID-ATLANTIC,
AND SOUTHEAST, SAT-SUN, JUN 6-7.

HEAVY RAIN FOR EASTERN PORTIONS OF THE MID-ATLANTIC, THU, JUN 4.

MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN GREAT BASIN AND
NORTHERN ROCKIES, SAT-SUN, JUN 6-7.

HIGH WINDS FOR COASTAL PARTS OF NORTHERN CALIFORNIA AND SOUTHWESTERN OREGON,
THU-FRI, JUN 4-5.

HEAVY RAIN FOR THE SOUTH COAST OF ALASKA AND THE ALASKA PANHANDLE, THU, JUN 4.

FLOODING IS OCCURRING OR POSSIBLE ACROSS PORTIONS OF THE SOUTH-CENTRAL CONUS,
SOUTHEASTERN WYOMING, AND CENTRAL COLORADO.

SEVERE DROUGHT FOR PARTS OF THE NORTHERN GREAT PLAINS, SOUTHWEST, GREAT BASIN,
CALIFORNIA, AND THE PACIFIC NORTHWEST.

SLIGHT CHANCE FOR MUCH ABOVE NORMAL MAXIMUM TEMPERATURES ACROSS PARTS OF
NORTHWESTERN CONUS AND NORTHERN CALIFORNIA, TUE-THU, JUN 9-11.

SLIGHT CHANCE FOR MUCH ABOVE NORMAL MAXIMUM TEMPERATURES ACROSS PARTS OF THE
UPPER AND LOWER GREAT LAKES, AND OHIO VALLEY, TUE, JUN 9.

DETAILED SUMMARY

FOR THURSDAY JUNE 04 - MONDAY JUNE 08: A STATIONARY FRONT IS PREDICTED TO
DEVELOP ACROSS THE MID AND SOUTHERN ATLANTIC COAST AT THE BEGINNING OF THE
PERIOD AND REMAIN IN PLACE FOR MUCH OF THE 3-7 DAY PERIOD. THIS FRONT MAY BRING
HEAVY RAIN TO EASTERN PORTIONS OF THE MID-ATLANTIC, MOST LIKELY TO SOUTHERN
VIRGINIA AND NORTH CAROLINA, ON THURSDAY. SOME AREAS MAY RECEIVE AN INCH AND A
HALF OF RAINFALL OR GREATER IN A 24-HOUR PERIOD.



A COLD FRONT IS FORECAST TO MOVE EASTWARD AND SOUTHEASTWARD FROM THE NORTHERN
PLAINS INTO THE NORTHEASTERN QUARTER OF THE CONUS THURSDAY TO SUNDAY. THIS COLD
FRONT IS ANTICIPATED TO BRING HEAVY RAIN TO PARTS OF THE UPPER AND MIDDLE
MISSISSIPPI VALLEY THURSDAY TO FRIDAY, WITH RAINFALL TOTALS POSSIBLY REACHING 2
INCHES OR GREATER IN A 24-HOUR PERIOD. AS THIS FRONT PROGRESSES SOUTHEASTWARD
TOWARD THE TENNESSEE VALLEY AND MID-ATLANTIC, THERE MAY ALSO BE HEAVY RAIN
ACROSS PARTS OF THE CENTRAL AND SOUTHERN APPALACHIANS, MID-ATLANTIC, AND
SOUTHEAST OVER THE WEEKEND. THERE IS, HOWEVER, SIGNIFICANT MODEL UNCERTAINTY
REGARDING THE POTENTIAL FOR HEAVY RAIN ACROSS THESE PARTS OF THE EASTERN CONUS
ASSOCIATED WITH THE DETAILS REGARDING THE EVOLUTION OF THIS FRONT. THE 06Z
OPERATIONAL GFS INDICATES MUCH HIGHER RAINFALL TOTALS ACROSS THE CENTRAL AND
SOUTHERN APPALACHIANS, COMPARED TO THE 00Z OPERATIONAL ECMWF MODEL.



AN AMPLIFIED UPPER-LEVEL RIDGE IS EXPECTED TO DEVELOP ACROSS THE NORTHWESTERN
CONUS, INCREASING THE LIKELIHOOD FOR MUCH ABOVE NORMAL TEMPERATURES ACROSS
PARTS OF THE NORTHERN GREAT BASIN AND NORTHERN ROCKIES OVER THE WEEKEND. DAILY
MAXIMUM TEMPERATURE ANOMALIES IN THIS AREA MAY REACH 16 DEGREES F ABOVE NORMAL
OR GREATER, WITH TEMPERATURES POTENTIALLY REACHING THE MID 90S (DEG F).



SURFACE HIGH PRESSURE IS ANTICIPATED TO BUILD ACROSS THE NORTHEASTERN PACIFIC
DURING THE 3-7 DAY PERIOD. THIS PATTERN MAY BRING HIGH WINDS TO PARTS OF
COASTAL CALIFORNIA AND SOUTHWESTERN OREGON THURSDAY TO FRIDAY, WITH SUSTAINED
WIND SPEEDS POTENTIALLY REACHING 40 KNOTS OR GREATER. WAVE HEIGHTS ASSOCIATED
WITH THESE WINDS ARE NOT EXPECTED TO BE SIGNIFICANT AT THIS TIME DUE TO THE
WINDS BEING NORTHERLY AND PARALLEL TO THE COAST.



A SURFACE LOW IS ANTICIPATED TO DEVELOP OVER THE GULF OF ALASKA BY THURSDAY AND
TRACK NORTHWARD INTO MAINLAND ALASKA BY FRIDAY. THIS PATTERN MAY BRING HEAVY
RAIN TO PARTS OF THE SOUTH COAST OF ALASKA AND THE ALASKA PANHANDLE ON
THURSDAY, JUNE 4. RAINFALL TOTALS MAY REACH 2 INCHES OR GREATER IN A 24-HOUR
PERIOD.



THERE ARE NUMEROUS AREAS OF ONGOING FLOODING ACROSS PARTS OF THE SOUTH-CENTRAL
CONUS, SOUTHEASTERN WYOMING, AND CENTRAL COLORADO ASSOCIATED WITH THE HEAVY
RAIN RECEIVED IN RECENT DAYS AND WEEKS. THERE IS AN ADDITIONAL POSSIBLE CHANCE
FOR FLOODING IN SOUTHEASTERN WYOMING. 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 TUESDAY JUNE 09 - MONDAY JUNE 15: THE AFOREMENTIONED UPPER-LEVEL RIDGE
ACROSS THE NORTHWESTERN CONUS DURING THE 3-7 DAY PERIOD IS ANTICIPATED TO
REMAIN IN PLACE UNTIL AT LEAST THE MIDDLE OF THE 8-14 DAY PERIOD, WITH THE
RIDGE AXIS SHIFTING SLIGHTLY EASTWARD FROM THE PACIFIC NORTHWEST TO THE
NORTHERN ROCKIES AND NORTHERN PLAINS BY NEXT TUESDAY. THIS PATTERN FAVORS
INCREASED CHANCES OF ANOMALOUSLY WARM TEMPERATURES ACROSS THE AREA. THEREFORE,
A SLIGHT CHANCE FOR MUCH ABOVE NORMAL MAXIMUM TEMPERATURES HAS BEEN IDENTIFIED
FOR PARTS OF THE NORTHWESTERN CONUS AND NORTHERN CALIFORNIA NEXT TUESDAY TO
THURSDAY, JUNE 9-11.



THERE IS A SLIGHT RISK FOR MUCH ABOVE NORMAL MAXIMUM TEMPERATURES FOR PARTS OF
THE UPPER AND LOWER GREAT LAKES, AND OHIO VALLEY NEXT TUESDAY, JUNE 9. THE GEFS
REFORECAST TOOL INDICATES A 20% CHANCE OF THIS AREA REACHING THE 85TH
PERCENTILE (COMPARED TO CLIMATOLOGY) FOR DAILY MAXIMUM TEMPERATURES. THERE IS
SIGNIFICANT UNCERTAINTY ASSOCIATED WITH THIS HAZARD DUE TO SIGNIFICANT MODEL
DIFFERENCES REGARDING THE SOUTHERN EXTENT OF A SURFACE LOW OVER EASTERN CANADA.
THE 00Z OPERATIONAL ECMWF SHOWS A MUCH MORE DEVELOPED SURFACE LOW EXTENDING
SOUTHWARD INTO THE MID-ATLANTIC, COMPARED TO THE 06Z OPERATIONAL GFS AND 06Z
GEFS, WHICH WOULD LIKELY DIMINISH CHANCES FOR MUCH ABOVE NORMAL TEMPERATURES.



THE MOST RECENT U.S. DROUGHT MONITOR, RELEASED MAY 28TH, INDICATES A DECREASE
(FROM 15.16 TO 14.20) IN THE PERCENTAGE OF THE CONUS IN SEVERE TO EXCEPTIONAL
DROUGHT (D2-D4). THIS REPRESENTS THE SMALLEST AREAL COVERAGE OF D2-D4 SINCE
MARCH 2011.

FORECASTER: MELISSA OU

$$



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