Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXUS21 KWNC 191955
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT AUGUST 19 2014

SYNOPSIS: SURFACE HIGH PRESSURE OVER SOUTHEASTERN CANADA IS FORECAST TO KEEP
NEW ENGLAND COOL AND DRY DURING THE FIRST HALF OF THIS PERIOD.  A COLD FRONT IS
EXPECTED TO STRETCH FROM THE MID-ATLANTIC COAST TO THE CENTRAL PLAINS AND IS
PREDICTED TO BE THE FOCUS FOR PRECIPITATION.  SOUTH OF THIS FRONT, TEMPERATURES
ARE FORECAST TO BE ABOVE NORMAL WITH DAILY HIGHS WELL INTO THE 90S.

HAZARDS

MUCH ABOVE NORMAL TEMPERATURES FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS,
FRI-SAT, AUG 22-23.

HEAVY RAIN FOR PARTS OF THE UPPER MIDWEST TO THE INTERMOUNTAIN WEST, THU-SAT,
AUG 22-23.

EXCESSIVE HEAT FOR PARTS OF THE MID-MISSISSIPPI VALLEY, FRI-MON, AUG 22-25.

EXCESSIVE HEAR FOR PARTS OF THE SOUTHEAST, FRI-SAT, AUG 22-23.

SEVERE DROUGHT FOR THE CENTRAL AND SOUTHERN GREAT PLAINS, SOUTHWEST, PACIFIC
NORTHWEST, GREAT BASIN, AND CALIFORNIA.

DETAILED SUMMARY

FOR FRIDAY AUGUST 22 - TUESDAY AUGUST 26: THIS FORECAST PERIOD IS EXPECTED TO
BEGIN WITH AN UPPER-LEVEL TROUGH IN THE SOUTHWEST, A RIDGE CENTERED ALONG THE
GULF COAST, AND ANOTHER TROUGH OVER THE GREAT LAKES.  IN PARTS OF KANSAS AND
OKLAHOMA, A COMBINATION OF SOUTHERLY FLOW, BOTH AT THE SURFACE AND ALOFT AS
WELL AS SINKING AIR DUE TO THE PRESENCE OF THE UPPER-LEVEL HIGH ARE FORECAST TO
BRING MUCH ABOVE NORMAL TEMPERATURES THROUGH THE BEGINNING OF THE WEEKEND.
DAILY HIGH TEMPERATURES ARE PREDICTED TO TOP OUT ABOVE 100 DEGREES F DURING
THESE DAYS, WHICH EQUATES TO TEMPERATURE ANOMALIES OF GREATER THAN 12 DEGREES F
ABOVE NORMAL.



IN ADDITION, EXCESSIVE HEAT IS EXPECTED IN PARTS OF THE MID-MISSISSIPPI VALLEY
FROM THE 22ND THROUGH THE 25TH AND IN PARTS OF THE SOUTHEAST FROM THE 22ND
THROUGH THE 23RD.  DAILY HEAT INDICES ARE FORECAST TO BE AT LEAST 105 DEGREES F
AND COULD EXCEED 110 DEGREES F.  BECAUSE THIS SUMMER HAS BEEN RELATIVELY COOL
AND WE ARE NEAR THE END OF THE SEASON, A HAZARD FOR EACH AREA WAS PLACED ON THE
MAP.



THE MAIN WEATHER FEATURE FOR THIS PERIOD IS PREDICTED TO BE AN UPPER-LEVEL
TROUGH DIGGING DOWN INTO THE UPPER MIDWEST.  AS ENERGY IS FORECAST TO ROTATE
AROUND ITS BASE, SURFACE CYCLOGENESIS IS PREDICTED TO THE LEE OF THE ROCKIES
AND THEN THE LOW PRESSURE SYSTEM IS FORECAST TO MOVE TO THE NORTHEAST.  HEAVY
RAIN IS EXPECTED FOR PARTS OF MONTANA, THE DAKOTAS, WESTERN MINNESOTA, AND
NORTHERN NEBRASKA ASSOCIATED WITH THIS ENERGY. RAINFALL TOTALS OF GREATER THAN
1 INCH IN 24 HOURS IS LIKELY.  SOME OF THIS MOISTURE MIGHT CONTINUE
SOUTHEASTWARDS TOWARDS THE CENTRAL APPALACHIANS ALONG A SURFACE COLD FRONT AND
CONTRIBUTE TO HEAVY RAIN IN THE EAST.  HOWEVER, AT THIS TIME, THERE IS TOO MUCH
UNCERTAINTY WITH THIS FORECAST TO WARRANT PLACING A HAZARD ON THE MAP.



TOWARDS THE END OF THIS PERIOD, AN UPPER-LEVEL LOW IS FORECAST BY SOME MODELS
TO CUT-OFF OFFSHORE OF THE EAST COAST.  IF THIS OCCURS, THERE IS A CHANCE FOR
HEAVY RAIN FOR PARTS OF THE NORTHERN MID-ATLANTIC AND NEW ENGLAND AS THE SLOW
MOVING LOW FOCUSES STRONG ONSHORE FLOW TO THESE REGIONS.

FOR WEDNESDAY AUGUST 27 - TUESDAY SEPTEMBER 02: UPPER-LEVEL DIVERGENCE IN THE
EASTERN PACIFIC IS EXPECTED TO CONTINUE THROUGHOUT THIS PERIOD.  MANY NUMERICAL
MODELS ARE PREDICTING CONTINUED TROPICAL SYSTEMS FORMING WEST OF CENTRAL
AMERICA AND MOVING NORTH TOWARDS BAJA CALIFORNIA.  WHILE IT IS IMPOSSIBLE TO
DETERMINE THE EXACT TRACK OF ANY PARTICULAR SYSTEM AT THIS TIME RANGE, THERE IS
A GREATER THAN NORMAL CHANCE OF TROPICAL MOISTURE STREAMING INTO THE SOUTHWEST
UNITED STATES WHICH WOULD INCREASE THE LIKELIHOOD OF HEAVY RAIN AND LOCALIZED
FLOODING.  THUS, PEOPLE WITH INTERESTS IN THIS PART OF THE COUNTRY SHOULD KEEP
UPDATED WITH CURRENT CONDITIONS COMING OUT OF LOCAL NWS OFFICES.



IN ADDITION, UPPER-LEVEL CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE FOR
TROPICAL DEVELOPMENT IN THE WESTERN ATLANTIC.  IN FACT, SOME NUMERICAL MODELS
ARE PREDICTING A TROPICAL SYSTEM MAKING LANDFALL ALONG THE GULF COAST.  BECAUSE
WE ARE NEARING THE CLIMATOLOGICAL PEAK OF THE ATLANTIC TROPICAL SEASON, PEOPLE
SHOULD KEEP UPDATED WITH FORECASTS COMING OUT OF THE NATIONAL HURRICANE CENTER.



THE MOST RECENT U.S. DROUGHT MONITOR, RELEASED ON AUGUST 12, SHOWS THE
PERCENTAGE OF CONUS IN SEVER DROUGHT ALMOST UNCHANGED FROM THE PREVIOUS WEEK AT
22%.

FORECASTER: KENNETH PELMAN

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.