899
FXUS01 KWBC 180816
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 AM EDT WED MAR 18 2026
VALID 12Z WED MAR 18 2026 - 12Z FRI MAR 20 2026
...AN ANOMALOUSLY EARLY HEATWAVE BEGINS TO INTENSIFY ACROSS THE
WESTERN U.S. AND EXPAND EAST INTO THE GREAT PLAINS...
...SUB-FREEZING TEMPERATURES DOWN TO THE EASTERN GULF COAST THIS
MORNING WILL BEGIN TO MODERATE...
...WET ACROSS WESTERN WASHINGTON AS LIGHT SNOW MOVES THROUGH THE
MIDWEST TODAY FOLLOWED BY A WINTRY MIX ACROSS THE GREAT LAKES
THURSDAY INTO FRIDAY...
A STRONG AND PERSISTENT UPPER-LEVEL HIGH PRESSURE SYSTEM IS
FORECAST TO FURTHER EXPAND AND REMAIN NEARLY STATIONARY OVER THE
DESERT SOUTHWEST. THIS WEATHER PATTERN, MORE INDICATIVE OF A
SUMMER REGIME THAN SPRING, WILL ALLOW A HIGHLY UNUSUAL HEATWAVE TO
BEGIN TO INTENSIFY ACROSS THE WESTERN U.S. SO EARLY IN THE SEASON.
PROGRESSIVELY INTENSE SUMMER-LIKE HEAT ACROSS CALIFORNIA AND INTO
THE GREAT BASIN/DESERT SOUTHWEST EARLY THIS WEEK WILL EXPAND
EASTWARD INTO THE ROCKIES AND THEN THE GREAT PLAINS BY THURSDAY.
NEW DAILY AND EVEN MONTHLY RECORD HIGHS FOR MARCH WILL LIKELY
ESTABLISH AT MANY LOCATIONS AS TEMPERATURES SOAR INTO THE 80S,
90S, AND EVEN THE 100S IN THE DESERT SOUTHWEST. IN ADDITION, MANY
LOCATIONS WITHIN THE DESERT SOUTHWEST ARE LIKELY TO SEE THEIR
EARLIEST 100 DEGREE TEMPERATURE ON RECORD. HEAT-RELATED
ADVISORIES AND WARNINGS ARE IN PLACE ACROSS THE DESERT SOUTHWEST
AND THE CENTRAL/SOUTHERN CALIFORNIA COASTS WHERE THIS HEAT MAY
POSE MORE NOTABLE HEALTH RISKS CONSIDERING BOTH HOW HOT THE
TEMPERATURES ARE AND HOW RELATIVELY EARLY THEY ARE OCCURRING. THE
HEAT WAVE LOOKS TO CONTINUE INTO THE WEEKEND BEFORE CONDITIONS
BEGIN TO RETURN CLOSER TO AVERAGE EARLY NEXT WEEK. ANOTHER CONCERN
WILL BE RAPID SNOWMELT IN THE MOUNTAINS LEADING TO RISING WATER
LEVELS AND SWIFT CURRENTS FOR REGIONAL RIVERS. ALTHOUGH AIR
TEMPERATURES ARE WARM, ANYONE ENTERING THE WATER IS AT RISK OF
COLD WATER SHOCK AND HYPOTHERMIA. MEANWHILE, WELL BELOW AVERAGE,
VERY CHILLY CONDITIONS ACROSS MOST OF THE EASTERN U.S. WILL BEGIN
TO MODERATE DURING THE NEXT COUPLE OF DAYS AS A HIGH PRESSURE
RIDGE BEGINS TO SLIDE OFF THE EAST COAST AND ALLOW SOUTHERLY FLOW
TO RETURN. AFTER ANOTHER MORNING OF FRIGID TEMPERATURES, WITH
FREEZE WARNINGS IN PLACE ACROSS MUCH OF THE SOUTHEAST, HIGHS
TEMPERATURES WILL QUICKLY REBOUND TO AVERAGE AND THEN ABOVE
AVERAGE, FIRST ACROSS THE MISSISSIPPI VALLEY THIS AFTERNOON AND
THEN TOWARDS THE EAST COAST THURSDAY AND FRIDAY.
MOST OF THE COUNTRY WILL BE RELATIVELY QUIET PRECIPITATION-WISE
THE NEXT COUPLE OF DAYS. THE HEAVIEST PRECIPITATION BY FAR WILL BE
LIMITED TO THE PACIFIC NORTHWEST AS MULTIPLE LOW PRESSURE WAVES
ALONG A STATIONARY MOVE ONSHORE, BRINGING MODERATE TO LOCALLY
HEAVY RAINFALL, WITH SOME ISOLATED FLOODING POSSIBLE, PARTICULARLY
ALONG UPSLOPE REGIONS OF THE OLYMPICS AND CASCADES. SNOW WILL BE
FAIRLY LIMITED TO THE HIGHEST ELEVATIONS OF THE MOUNTAINS GIVEN
THE RELATIVELY MILD AIR THAT CAN BE TRACED BACK TO HAWAII.
MEANWHILE, A SWATH OF MAINLY LIGHT SNOW WILL MOVE ACROSS THE UPPER
MIDWEST INTO THE GREAT LAKES TODAY BEFORE REACHING INTO PORTIONS
OF THE INTERIOR NORTHEAST/APPALACHIANS ON THURSDAY. A WINTRY
MIX/RAIN WILL MOVE ACROSS THE GREAT LAKES INTO THE INTERIOR
NORTHEAST ON THURSDAY. THIS SHOULD BE FOLLOWED BY ANOTHER ROUND OF
WINTRY MIX THURSDAY NIGHT INTO FRIDAY MORNING ACROSS THE UPPER
GREAT LAKES AHEAD OF AN ALBERTA CLIPPER.
MEANWHILE, CRITICAL FIRE WEATHER CONCERNS HAVE SHIFTED INTO
WYOMING TODAY AND IS EXPECTED TO LAST INTO EARLY ON FRIDAY AS DRY,
GUSTY AND WARM DOWNSLOPE WINDS DEVELOP. STRONG AND GUSTY
DOWNSLOPE WINDS ARE FORECAST ACROSS MONTANA ON THE SOUTHERN SIDE
OF THE CLIPPER SYSTEM.
KONG/PUTNAM
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