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FXUS21 KWNC 292121
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT JUNE 29 2012
SYNOPSIS: RIDGING IS FORECAST TO DOMINATE OVER THE CENTRAL PORTION OF THE
COUNTRY. AN UPPER-LEVEL DISTURBANCE IS FORECAST TO MOVE ACROSS THE NORTHERN
TIER OF THE COUNTRY DURING THE EARLY PORTIONS OF NEXT WEEK. A TIGHT SURFACE
PRESSURE GRADIENT IS EXPECTED ACROSS NORTHERN CALIFORNIA DURING THE EARLY TO
MIDDLE PART OF NEXT WEEK. A FRONTAL BOUNDARY IS FORECAST TO BE IN PLACE FROM
THE CENTRAL PLAINS TO THE MID-ATLANTIC REGION DURING MUCH OF THIS PERIOD.
SURFACE LOW PRESSURE MOVING ACROSS THE ALEUTIANS AND THE GULF OF ALASKA IS
EXPECTED TO CONTRIBUTE TO WET CONDITIONS ACROSS SOUTHERN PORTIONS OF ALASKA.
HAZARDS
EXCESSIVE HEAT FROM THE TENNESSEE VALLEY TO THE SOUTHEAST AND MID-ATLANTIC
COASTS, JUL 2-4.
EXCESSIVE HEAT FROM THE NORTHERN HIGH PLAINS TO THE TENNESSEE VALLEY, JUL 3-6.
HIGH WINDS ACROSS NORTHERN CALIFORNIA AND SOUTHERN OREGON, JUL 3-4.
FLOODING ACROSS PARTS OF MINNESOTA, JUL 2-6.
FLOODING ACROSS PARTS OF FLORIDA, JUL 3-4.
FLOODING ACROSS PARTS OF NORTHERN IDAHO, JUL 3-6.
SEVERE DROUGHT FOR PARTS OF THE SOUTHEAST, MID-WEST, LOWER AND MIDDLE
MISSISSIPPI VALLEY, CENTRAL/SOUTHERN GREAT PLAINS, RIO GRANDE VALLEY,
CENTRAL/SOUTHERN ROCKIES, THE SOUTHWEST, GREAT BASIN, AND HAWAII.
DETAILED SUMMARY
FOR MONDAY JULY 02 - FRIDAY JULY 06: A RIDGE OF HIGH PRESSURE IS EXPECTED TO
DEVELOP ACROSS THE SOUTHEAST PORTIONS OF THE COUNTRY. THAT FEATURE SHOULD
SUPPORT EXCESSIVE HEAT ACROSS THE SOUTHEAST, WITH HEAT INDEX VALUES EXCEEDING
105 DEGREES F FROM THE CENTRAL GULF COAST TO THE PIEDMONT IN THE CAROLINAS. A
BREAK IN THE HEAT IS EXPECTED DURING THE LATTER HALF OF NEXT WEEK.
WHILE THE EASTERN THIRD OF THE COUNTRY IS EXPECTING A SLIGHT BREAK FROM THE
EXCESSIVELY HOT CONDITIONS DURING THE END OF NEXT WEEK, PORTIONS OF THE GREAT
PLAINS AND MISSISSIPPI VALLEY ARE EXPECTED TO EXPERIENCE AN EXTENDED PERIOD OF
ABNORMALLY HOT CONDITIONS. HEAT INDEX VALUES ARE EXPECTED TO EXCEED 105
DEGREES F ACROSS THE DAKOTAS, IOWA, AND AS FAR SOUTH AS ARKANSAS.
A TROUGH IS EXPECTED TO MOVE ACROSS THE PACIFIC NORTHWEST DURING THE SECOND
HALF OF THE WEEKEND. THE STORM PREDICTION CENTER HAS INDICATED THAT AN AREA
FROM ARIZONA TO WYOMING IS LIKELY TO EXPERIENCE CONDITIONS APPROACHING CRITICAL
FIRE WEATHER CONDITIONS, BUT UNCERTAINTY AS TO WHETHER AREAS WILL EXCEED
CRITICAL FIRE WEATHER THRESHOLDS IS STILL TOO HIGH TO INDICATE AN AREA ON THE
MAP.
A LOW-PRESSURE SYSTEM IS FORECAST TO IMPACT SOUTHERN ALASKA DURING WEDNESDAY
THROUGH FRIDAY. RAINFALL ACROSS THE SOUTHERN COAST AND SOUTHERN MOUNTAINS IS
FORECAST TO BE NEAR HAZARDOUS THRESHOLDS, BUT SOME MODELS ARE INDICATING LOWER
AMOUNTS, SO NO HAZARD IS DEPICTED.
DURING THE SECOND HALF OF NEXT WEEK, MODEL SOLUTIONS FROM THE GFS AND EUROPEAN
CENTER INDICATE A SURGE OF MOISTURE MOVING NORTH ACROSS THE SOUTHWESTERN U.S.
THIS SURGE OF MOISTURE IS LIKELY TO BRING THE FIRST SIGNIFICANT RAINS TO
PORTIONS OF UTAH AND ARIZONA, TRIGGERING LOCALIZED FLASH FLOODS AND POTENTIALLY
NEW WILD FIRES DUE TO LIGHTNING STRIKES.
FOR SATURDAY JULY 07 - FRIDAY JULY 13: A SHORT-WAVE TROUGH IS FORECAST TO MOVE
ACROSS THE PACIFIC NORTHWEST DURING NEXT WEEKEND. THIS INCREASES THE THREAT OF
THUNDERSTORMS ACROSS THE NORTHERN GREAT PLAINS DURING NEXT WEEKEND.
SEVERE DROUGHT, WITH LOCALLY MORE INTENSE CONDITONS ARE EXPECTED TO CONTINUE
ACROSS THE SOUTHEAST, MID-WEST, LOWER AND MIDDLE MISSISSIPPI VALLEY,
CENTRAL/SOUTHERN GREAT PLAINS, RIO GRANDE VALLEY, CENTRAL ROCKIES, GREAT BASIN,
AND HAWAII. SOME RELIEF IS POSSIBLE ACROSS THE SOUTHERN ROCKIES THE SOUTHWEST.
FORECASTER: MATTHEW ROSENCRANS
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