Prognostic Meteorological Discussion
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FXUS21 KWNC 261853
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT MAY 26 2016

SYNOPSIS: A LOW PRESSURE SYSTEM IS EXPECTED TO AFFECT THE COASTAL SOUTHEAST
DURING THE MEMORIAL DAY WEEKEND. AN AREA OF UPPER-LEVEL LOW PRESSURE IS
EXPECTED TO SHIFT EAST FROM THE WESTERN CONUS WITH A COLD FRONT PROGRESSING
SOUTHEAST ACROSS THE GREAT PLAINS DURING THE EARLY TO MIDDLE PART OF NEXT WEEK.
AN AREA OF UPPER-LEVEL HIGH PRESSURE IS LIKELY TO PERSIST ACROSS ALASKA THROUGH
THE END OF MAY, WITH ONSHORE FLOW EXPECTED TO INCREASE ACROSS SOUTHERN ALASKA
EARLY IN JUNE. DURING WEEK-2, A STRONG AREA OF UPPER-LEVEL HIGH PRESSURE IS
EXPECTED TO CONTINUE ACROSS THE NORTHWESTERN CONUS.

HAZARDS

LOCALLY HEAVY RAIN FOR THE COASTAL SOUTHEAST, SUN-MON, MAY 29-30.

LOCALLY HEAVY RAIN FOR PARTS OF THE GREAT PLAINS AND LOWER MISSOURI RIVER
VALLEY, SUN-TUE, MAY 29-31.

LOCALLY  HEAVY RAIN FOR PARTS OF TEXAS, WED-THU, JUNE 1-2.

FLOODING IS OCCURRING, IMMINENT, LIKELY, OR POSSIBLE ACROSS PARTS OF THE
CENTRAL AND SOUTHERN PLAINS, CENTRAL ROCKIES, LOWER MISSOURI RIVER VALLEY, AND
MIDWEST, SUN-MON, MAY 29-30.

MUCH ABOVE-NORMAL TEMPERATURES FOR PARTS OF THE NORTHEAST, SUN, MAY 29.

MUCH ABOVE-NORMAL TEMPERATURES FOR PARTS OF THE PACIFIC NORTHWEST AND IDAHO,
WED-THU, JUNE 1-2.

A SLIGHT RISK OF MUCH ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE WESTERN U.S.,
FRI-WED, JUNE 3-8.

A MODERATE RISK OF MUCH ABOVE-NORMAL TEMPERATURES FOR PARTS OF THE PACIFIC
NORTHWEST, IDAHO, AND NORTHERN CALIFORNIA, FRI-MON, JUNE 3-6.

SEVERE DROUGHT ACROSS PARTS OF CALIFORNIA, NEVADA, NORTH-CENTRAL WYOMING, AND
HAWAII.

DETAILED SUMMARY

FOR SUNDAY MAY 29 - THURSDAY JUNE 02: AN AREA OF LOW PRESSURE IS CURRENTLY
DEVELOPING A FEW HUNDRED MILES NORTHEAST OF THE BAHAMAS. MODEL GUIDANCE
CONTINUES TO INDICATE THIS MID-LEVEL LOW AND A WEAK SURFACE LOW APPROACH THE
SOUTHEAST COAST BY THE WEEKEND. REGARDLESS OF ITS INTENSITY, LOCALLY HEAVY RAIN
(MORE THAN 1 INCH PER 24 HOURS) IS EXPECTED ACROSS THE COASTAL SOUTHEAST
THROUGH AT LEAST MEMORIAL DAY. MODEL SOLUTIONS INDICATE TWO DIFFERENT OUTCOMES
WITH EITHER THE LOW DISSIPATING ALONG THE SOUTHEAST COAST OR MOVING NORTHEAST
AND OFFSHORE OF THE OUTER BANKS. AS OF 825AM EDT ON THURSDAY, THE NATIONAL
HURRICANE CENTER STATES THAT THERE IS A 70 PERCENT CHANCE OF TROPICAL CYCLONE
FORMATION OFFSHORE OF THE SOUTHEAST. PLEASE REFER TO THE NATIONAL HURRICANE
CENTER FOR THE LATEST UPDATES ON THIS POTENTIAL TROPICAL OR SUBTROPICAL STORM.



SHORTWAVE TROUGHS WITHIN SOUTHWEST FLOW ALOFT ARE EXPECTED TO TRIGGER DAILY
CONVECTION ACROSS THE GREAT PLAINS AND MISSOURI RIVER VALLEY FROM MAY 29 TO 31.
THE FOCUS FOR LOCALLY HEAVY RAIN (MORE THAN 1 INCH PER 24 HOURS) IS EXPECTED TO
SHIFT SOUTH BY THE BEGINNING OF JUNE AS A COLD FRONT PROGRESSES INTO THE
SOUTHERN GREAT PLAINS. ON JUNE 1 AND 2, MOIST, SOUTHEASTERLY FLOW INTERACTING
WITH THE TAIL END OF A FRONT IS LIKELY TO RESULT IN HEAVY RAINFALL ACROSS PARTS
OF TEXAS. ALTHOUGH THE RISK FOR SEVERE THUNDERSTORMS EXISTS ACROSS THE GREAT
PLAINS DURING THIS PERIOD, LOW PREDICTABILITY ON THE MESOSCALE DETAILS,
PRECLUDES DESIGNATION OF A SEVERE WEATHER HAZARD AT THIS TIME.



RECENT RAINFALL HAS RESULTED IN MINOR TO MODERATE FLOODING ACROSS PARTS OF THE
CENTRAL CONUS AND IS LIKELY TO CONTINUE INTO NEXT WEEK. FOR EXAMPLE, MODERATE
FLOODING IS FORECAST TO PERSIST ALONG PARTS OF THE NORTH PLATTE RIVER IN
NEBRASKA. ANY HEAVY RAINFALL COULD EXACERBATE ONGOING FLOODING AND MAY CAUSE
ADDITIONAL FLOODING DUE TO THE ANTECEDENT WETNESS.



RIDGING ALOFT IS EXPECTED TO RESULT IN MUCH ABOVE-NORMAL TEMPERATURES ACROSS
PARTS OF THE NORTHEAST THROUGH SUNDAY, MAY 29. MAXIMUM TEMPERATURES ARE
FORECAST TO AVERAGE 10 TO 15 DEGREES F ABOVE-NORMAL ACROSS THE HIGHLIGHTED AREA
ON THE MAP WITH SOME LOCATIONS POSSIBLY REACHING 90 DEGREES F.



AN INCREASE IN 500-HPA HEIGHTS IS LIKELY TO BRING A WARMING TREND TO THE
WESTERN CONUS NEXT WEEK. MUCH ABOVE-NORMAL TEMPERATURES (10 TO 15 DEGREES F)
ARE FORECAST ACROSS THE INTERIOR PACIFIC NORTHWEST BY WEDNESDAY, JUNE 1.



UNSEASONABLY WARM TEMPERATURES ARE LIKELY TO PERSIST ACROSS SOUTHWEST ALASKA AS
RIDGING ALOFT REMAINS DOMINANT THROUGH AT LEAST THE END OF MAY. ALTHOUGH THE 6Z
GFS ENSEMBLE MEAN INDICATES THAT TEMPERATURES WILL AVERAGE MORE THAN 12 DEGREES
F ABOVE-NORMAL ACROSS THIS REGION, THESE TEMPERATURES ARE NOT CONSIDERED TO BE
HAZARDOUS.

FOR FRIDAY JUNE 03 - THURSDAY JUNE 09: THE GFS AND ECMWF ENSEMBLE MEANS DEPICT
A STRONG UPPER-LEVEL RIDGE CENTERED ACROSS THE NORTHWESTERN CONUS DURING
WEEK-2. A SLIGHT RISK OF MUCH ABOVE-NORMAL TEMPERATURES IS POSTED FOR MUCH OF
THE WESTERN CONUS WHERE THE GEFS REFORECAST TOOL INDICATES THAT DAILY MAXIMUM
TEMPERATURES HAVE A 20 PERCENT CHANCE OR MORE OF EXCEEDING THE 85TH PERCENTILE
COMPARED TO CLIMATOLOGY. THE MORE ANOMALOUS HEAT IS EXPECTED TO BE CENTERED
OVER THE INTERIOR PACIFIC NORTHWEST AND NORTHERN CALIFORNIA WHERE THE GEFS
REFORECAST TOOL INDICATES THAT DAILY MAXIMUM TEMPERATURES HAVE AT LEAST A 40
PERCENT CHANCE OF EXCEEDING THE 85TH PERCENTILE COMPARED TO CLIMATOLOGY.



ONSHORE FLOW IS FORECAST TO FAVOR ABOVE-MEDIAN PRECIPITATION ACROSS SOUTHERN
COASTAL ALASKA, ESPECIALLY FROM THE ALASKA PENINSULA TO THE PRINCE WILLIAM
SOUND. PRECIPITATION AMOUNTS ARE NOT EXPECTED TO REACH HAZARDS CRITERIA.



ACCORDING TO THE U.S. DROUGHT MONITOR, VALID ON MAY 24, SEVERE, OR GREATER
INTENSITY, DROUGHT COVERS 3.69 PERCENT OF THE U.S. DROUGHT MONITOR AREAS
(INCLUDING ALASKA, HAWAII, AND PUERTO RICO), A DECREASE FROM 4.07 PERCENT LAST
WEEK. THIS IS THE LOWEST COVERAGE SINCE OCTOBER 2010.

FORECASTER: BRAD PUGH

$$



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