Prognostic Meteorological Discussion
Issued by NWS

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FXUS21 KWNC 101925
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 10 2014

SYNOPSIS: A STRONG COLD FRONT IS EXPECTED TO MOVE FROM THE GREAT LAKES TO THE
EAST COAST AT THE BEGINNING OF THIS PERIOD.  BEHIND THE FRONT, COOL HIGH
PRESSURE IS FORECAST TO BRING BELOW NORMAL TEMPERATURES TO MOST OF THE EASTERN
HALF OF THE LOWER 48.  IN THE INTERMOUNTAIN WEST, HIGH PRESSURE IS FORECAST TO
PREVAIL, FAVORING WARMER TEMPERATURES.

HAZARDS

MUCH ABOVE-NORMAL TEMPERATURES FOR PARTS OF THE GREAT BASIN AND NORTHERN
INTERMOUNTAIN WEST, SUN-FRI, JUL 13-18.

HIGH WINDS FOR THE NORTHERN SLOPE OF ALASKA, TUE-WED, JUL 15-16.

HIGH WINDS FOR THE WESTERN ALEUTIANS, WED-THU, JUL 16-17.

SEVERE WEATHER FOR PARTS OF THE MID-ATLANTIC AND NORTHEAST, TUE, JUL 15.

HEAVY RAIN FOR COASTAL PORTIONS OF THE CAROLINAS, TUE-WED, JUL 15-16.

HEAVY RAIN FOR PARTS OF THE SOUTHERN ROCKIES, SUN-WED, JUL 13-16.

FLOODING OCCURRING OR IMMINENT FOR PARTS OF NORTH DAKOTA AND THE MIDDLE
MISSISSIPPI VALLEY.

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

DETAILED SUMMARY

FOR SUNDAY JULY 13 - THURSDAY JULY 17: THE FIRST PART OF THIS FORECAST PERIOD
IS EXPECTED TO FEATURE AN AMPLIFIED UPPER-LEVEL TROUGH ACROSS THE GREAT LAKES
REGION.  AS THIS TROUGH AMPLIFIES, A SURFACE COLD FRONT IS PREDICTED TO MOVE
FROM THE UPPER MIDWEST TO THE SOUTHEAST.  AS IT MAKES ITS WAY TOWARDS THE EAST
COAST, WARM, MOIST AIR IN ADVANCE OF THE FRONT COUPLED WITH AN UPPER-LEVEL JET
STREAK IS EXPECTED TO SET THE STAGE FOR A SEVERE WEATHER OUTBREAK FROM SOUTHERN
VERMONT AND NEW HAMPSHIRE TO NORTHERN NORTH CAROLINA.  HOWEVER, THE GREATEST
AXIS OF MOISTURE IS PREDICTED TO STAY FARTHER SOUTH, WHICH MEANS THAT THE
GREATEST CHANCE OF HEAVY RAIN EXISTS FROM SOUTHEASTERN VIRGINIA TO SOUTH
CAROLINA.



THE COLD FRONT IS FORECAST TO STRETCH FROM THE EAST COAST BACK TO THE ROCKIES
AS HIGH PRESSURE IS EXPECTED TO BE SITUATED OVER THE NORTHERN AND CENTRAL
PLAINS.  THE COMBINATION OF UPSLOPE FLOW AND THE FOCUS OF PRECIPITATION
ASSOCIATED WITH THE FRONT, HEAVY RAIN IS ANTICIPATED FOR PARTS OF THE SOUTHERN
ROCKIES.  WITH RAINFALL TOTALS OF MORE THAN 2 INCHES PREDICTED OVER HIGH
TERRAIN, LOCALIZED FLASH FLOODING IS POSSIBLE AS WELL.



IN ADDITION, AN UPPER-LEVEL RIDGE IS FORECAST TO AMPLIFY IN THE WESTERN STATES,
FAVORING MUCH ABOVE NORMAL TEMPERATURES IN PARTS OF THE PACIFIC AND
INTERMOUNTAIN WEST, WITH DAILY MAXIMUM TEMPERATURES 12 TO 20 DEGREES ABOVE
NORMAL POSSIBLE THROUGHOUT THIS ENTIRE FORECAST PERIOD.



IN ALASKA, A LARGE UPPER-LEVEL LOW SLOWLY ROTATING NEAR THE ALEUTIANS IS
EXPECTED TO BE THE IMPETUS FOR UNSETTLED WEATHER.  AS THIS PERIOD ENDS, A
SURFACE LOW IS FORECAST TO STRENGTHEN AND ROTATE AROUND THE UPPER-LEVEL LOW.
THIS STORM IS PREDICTED TO MOVE PARALLEL TO THE ALEUTIANS AND BRING HIGH WINDS
OF 30-40 KNOTS TO THE ISLANDS.  IN ADDITION, A SEPARATE UPPER-LEVEL SHORTWAVE
IS FORECAST TO MOVE EAST FROM NORTHERN RUSSIA.  IT IS EXPECTED TO BRING HIGH
WINDS OF AT LEAST 30 KNOTS TO THE NORTH SLOPE FROM THE 15TH TO THE 16TH.
SIGNIFICANT RAINFALL IS ALSO POSSIBLE, ALTHOUGH THERE IS A HIGH LEVEL OF
UNCERTAINTY AS TO THE EXACT AMOUNT OF RAIN THAT WILL FALL, THUS NO
PRECIPITATION HAZARDS ARE DENOTED AT THIS TIME ON THE MAP.



FLOODING IN THE MID-MISSISSIPPI VALLEY AND NORTH DAKOTA IS PREDICTED TO
CONTINUE DURING THIS FORECAST PERIOD, AS WATER FROM RECENT RAINFALLS OF 3-8
INCHES (AND UP TO 19 INCHES DURING THE MONTH OF JUNE) CONTINUES TO FLOW INTO
THE LARGE RIVERS.

FOR FRIDAY JULY 18 - THURSDAY JULY 24: THE LATEST NUMERICAL MODELS ARE ONCE
AGAIN INDICATING THAT THE UPPER-LEVEL RIDGE IN THE WEST WILL PERSIST FOR AT
LEAST THE FIRST DAY IN THIS FORECAST PERIOD, ALLOWING FOR THE CONTINUATION OF
MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE INTERMOUNTAIN WEST.



BASED ON THE LATEST DROUGHT MONITOR VALID ON JULY 8, THE COVERAGE OF SEVERE TO
EXCEPTIONAL DROUGHT ACROSS THE CONTINENTAL U.S. REMAINED NEARLY STEADY AT JUST
UNDER 25 PERCENT.

FORECASTER: KENNETH PELMAN

$$



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