Prognostic Meteorological Discussion
Issued by NWS

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FXUS21 KWNC 071924
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JULY 07 2015

SYNOPSIS: A FRONT LOCATED IN THE MIDDLE OF THE COUNTRY IS PREDICTED TO BE THE
FOCUS FOR WET WEATHER DURING THE BEGINNING OF THIS OUTLOOK PERIOD. HIGH
PRESSURE AND HOT WEATHER IS ANTICIPATED FOR THE SOUTHEAST, WHILE MOST OF THE
SOUTH REMAINS DRY.

HAZARDS

ENHANCED WILDFIRE RISK FOR PARTS OF MAINLAND ALASKA, FRI-TUE, JUL 10-21.

EXCESSIVE HEAT FOR PARTS OF THE SOUTHEAST, SAT-MON, JUL 11-13.

ONGOING OR LIKELY FLOODING ACROSS PARTS OF THE MIDDLE MISSISSIPPI VALLEY.

SEVERE DROUGHT FOR PARTS OF THE WESTERN THIRD OF THE CONUS, SOUTHEAST GEORGIA,
AND SOUTH FLORIDA.

DETAILED SUMMARY

FOR FRIDAY JULY 10 - TUESDAY JULY 14: THIS FORECAST PERIOD IS EXPECTED TO BEGIN
WITH AN AMPLIFIED UPPER-LEVEL TROUGH CENTERED JUST OFF THE CALIFORNIA COAST,
WITH A STRONG SOUTHEASTERN RIDGE.  IN ADVANCE OF THE TROUGH, STRONG WINDS ARE
EXPECTED TO LEAD TO AN ENHANCED RISK OF WILDFIRES, IN PARTS OF EXTREME SOUTHERN
NEVADA, SOUTHWESTERN UTAH, AND NORTHWESTERN ARIZONA.  HOWEVER, NO HAZARD IS
PLACED ON THE MAP AT THIS TIME, DUE TO ENOUGH UNCERTAINTY PRECLUDING THE STORM
PREDICTION CENTER FROM ISSUING AN AREA ON THEIR CATEGORICAL FORECAST.



UNDERNEATH THE SOUTHEASTERN RIDGE, EXCESSIVE HEAT IS EXPECTED FROM NORTHERN
FLORIDA TO NORTH CAROLINA AS DAILY MAXIMUM HEAT INDICES COULD APPROACH 110
DEGREES, WHICH WOULD PROMPT HEAT THREATS TO BE ISSUED FROM LOCAL NWS OFFICES.



IN THE MIDDLE OF THE LOWER 48, SOUTHWEST-NORTHEAST FLOW IS FORECAST TO BRING A
PERIOD OF ACTIVE WEATHER FROM THE DESERT SOUTHWEST TO THE GREAT LAKES.  THE
COMBINATION OF MOISTURE COMING IN FROM THE EASTERN PACIFIC, AND FAVORABLE
UPPER-LEVEL SUPPORT, HEAVY RAIN IS POSSIBLE FROM THE SOUTHWEST TO THE OHIO
VALLEY.  HOWEVER, AT THIS TIME, THESE AREAS ARE PREDICTED TO BE VERY SMALL IN
NATURE, AND NO LARGE SCALE HAZARD IS DENOTED ON THE MAP.  ANY HEAVY RAIN THAT
DOES FALL IN THE MISSISSIPPI AND OHIO VALLEYS ALSO HAS THE POTENTIAL OF
EXACERBATING ONGOING FLOODING.



TOWARDS THE MIDDLE OF THIS PERIOD, THE SOUTHEASTERN RIDGE IS EXPECTED TO
RETROGRADE AND MOVE INTO THE SOUTHERN PLAINS, WHICH IS FORECAST TO AMPLIFY THE
NORTHERN STREAM IN THE NORTHERN ROCKIES AND NORTHERN PLAINS.  WHILE LOCALIZED
MUCH ABOVE NORMAL TEMPERATURES ARE NOT OUT OF THE QUESTION, THE FORECAST
PATTERN IS LESS AMPLIFIED TODAY THAN IN MODEL RUNS YESTERDAY.  THIS PATTERN
ALSO FAVORS THE GENERATION OF MESOSCALE CONVECTIVE SYSTEMS MOVING INTO THE
GREAT LAKES AND THE NORTHERN MID-ATLANTIC.  THESE SYSTEMS COULD EASILY BRING
HEAVY RAIN AND SEVERE WEATHER, BUT THE EXACT LOCATION AND TIMING OF ANY SYSTEMS
IS VERY DIFFICULT TO ASCERTAIN AT THIS LEAD TIME.



A PERSISTENT UPPER-LEVEL LOW IS FORECAST TO REMAIN NORTH OF THE ALEUTIANS,
BRINGING SOUTHERLY FLOW TO THE ALASKAN MAINLAND.  THIS WOULD MEAN ANY MOISTURE
WOULD FALL OVER THE SOUTHERN PART OF THE STATE, KEEPING THE INTERIOR WARM AND
DRY.  THUS, A CONTINUED ENHANCED RISK OF WILDFIRES REMAINS FOR THE ENTIRE
OUTLOOK PERIOD.

FOR WEDNESDAY JULY 15 - TUESDAY JULY 21: THE GENERAL PREDICTED UPPER-LEVEL FLOW
FOR THIS PERIOD KEEPS THE STORM TRACK ALONG THE U.S.-CANADIAN BORDER, TYPICAL
FOR THIS TIME OF YEAR.  THIS WOULD FAVOR ABOVE MEDIAN PRECIPITATION FOR THE
NORTHERN TIER AND BELOW-MEDIAN FOR THE SOUTHERN STATES.



WITH EXPECTED RAINFALL IN THE 1-7 DAY PERIOD, COMBINED WITH ANTECEDENT
CONDITIONS, CONTINUED FLOODING ALONG THE MISSISSIPPI AND ILLINOIS RIVERS IS
POSSIBLE FOR THE ENTIRETY OF THIS FORECAST PERIOD.



THE MOST RECENT U.S. DROUGHT MONITOR, VALID ON JUNE 30, INDICATES AN INCREASE
(FROM 14.31 TO 15.54) IN THE PERCENTAGE OF THE CONUS IN SEVERE TO EXCEPTIONAL
DROUGHT (D2-D4). DROUGHT INTENSIFICATION (IMPROVEMENT) WAS OBSERVED OVER PARTS
OF THE NORTHWEST AND SOUTHEAST (MID-ATLANTIC AND NORTHEAST).



FORECASTER: KENNETH PELMAN

$$




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