483
FXUS21 KWNC 011817
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT APRIL 01 2026
SYNOPSIS: THE RETURN OF DEVELOPING MID-LEVEL LOW (HIGH) PRESSURE ACROSS THE
WESTERN (EASTERN) CONTIGUOUS U.S. (CONUS) INCREASES CHANCES FOR HEAVY
PRECIPITATION AND HIGH WINDS MAINLY ACROSS THE GREAT PLAINS AND MISSISSIPPI
VALLEY LATER NEXT WEEK. EARLY IN WEEK-2, MID-LEVEL LOW PRESSURE IS EXPECTED TO
BRING BELOW-NORMAL TEMPERATURE ACROSS THE NORTHEASTERN CONUS, WHERE THERE ARE
INCREASED CHANCES FOR NEAR AND/OR SUBFREEZING TEMPERATURES TO POTENTIALLY
IMPACT EMERGING SPRINGTIME VEGETATION IN PARTS OF THE MID-ATLANTIC AND CENTRAL
TO SOUTHERN APPALACHIANS.
HAZARDS
MODERATE RISK OF HEAVY PRECIPITATION FOR PARTS OF THE SOUTHERN AND CENTRAL
PLAINS, MISSISSIPPI VALLEY, FRI-SAT, APR 10-11.
SLIGHT RISK OF HEAVY PRECIPITATION FOR MUCH OF THE GREAT PLAINS AND MISSISSIPPI
VALLEY, AND PARTS OF THE TENNESSEE AND OHIO VALLEYS, AND GREAT LAKES, THU-SUN,
APR 9-12.
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE MID-ATLANTIC AND
APPALACHIANS, THU, APR 9.
SLIGHT RISK OF HIGH WINDS FOR PORTIONS OF THE ROCKIES, GREAT PLAINS, AND
MISSISSIPPI VALLEY, THU-SUN, APR 9-12.
DETAILED SUMMARY
FOR SATURDAY APRIL 04 - WEDNESDAY APRIL 08:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY APRIL 09 - WEDNESDAY APRIL 15: TOWARDS THE MIDDLE TO LATTER PART
OF NEXT WEEK, DYNAMICAL MODELS ARE IN GOOD AGREEMENT FEATURING SHORTWAVE
TROUGHING LIFTING OUT OVER THE EASTERN U.S., AND BEING REPLACED BY ANOMALOUS
500-HPA RIDGING SHIFTING EASTWARD FROM THE GREAT PLAINS. AT THE SURFACE, THE
PASSAGE OF A FAIRLY LARGE FRONTAL SYSTEM TIED TO THE DEPARTING MID-LEVEL TROUGH
IS FAVORED, WHERE THERE IS BETTER MODEL SUPPORT FOR A SHOT OF POTENTIALLY
IMPACTFUL COLD AIR OVER THE NORTHEASTERN CONUS BEFORE TEMPERATURES ARE EXPECTED
QUICKLY MODERATE WITH THE RIDGING ALOFT MOVING IN. AS THIS RIDGING BECOMES
ESTABLISHED AND AMPLIFIES OVER THE NORTHEASTERN U.S. LATE NEXT WEEK, MODELS
REMAIN CONSISTENT IN DEVELOPING A DEEPENING TROUGH OVER THE INTERIOR WEST,
FAVORABLE FOR SURFACE LOW FORMATION IN THE LEE OF THE ROCKIES, AND LEADING TO
INCREASED CHANCES FOR POTENTIALLY HEAVY PRECIPITATION AND EPISODES OF HIGH
WINDS ACROSS THE PLAINS AND MISSISSIPPI VALLEY. LATER IN WEEK-2, 500-HPA HEIGHT
FORECASTS FROM THE GEFS AND ECMWF ENSEMBLES HAVE BECOME BETTER ALIGNED WITH THE
EVOLUTION OF THE PATTERN SINCE YESTERDAY, AND FEATURE MORE MID-LEVEL RIDGING
REDEVELOPING ACROSS THE WESTERN CONUS. THE PATTERN SHIFT COULD SPELL THE RETURN
OF UNSEASONABLY WARM TEMPERATURES THROUGHOUT MANY PARTS OF THE WESTERN AND
CENTRAL CONUS LATER IN APRIL.
IN THE WAKE OF A FRONTAL SYSTEM OVER THE EASTERN U.S. LATE IN WEEK-1, BOTH THE
LATEST GEFS AND ECMWF ENSEMBLES FAVOR A STRONGER MEAN SURFACE HIGH OVER THE
OHIO VALLEY. WHILE MUCH OF THE ACCOMPANYING ANOMALOUS COLD AIR LOOKS TO BEGIN
TO MODERATE WHILE SHIFTING OFFSHORE, RAW TEMPERATURE TOOLS CONTINUE TO SHOW
FAIRLY STRONG NEGATIVE TEMPERATURE DEPARTURES OVER THE EASTERN SEABOARD, WITH
INCREASED CHANCES FOR NIGHTTIME MINIMUM TEMPERATURE FALLING BELOW FREEZING AS
FAR SOUTH AS THE CAROLINAS. THIS IS ALSO SUPPORTED BY THE PROBABILISTIC
EXTREMES TOOLS (PETS) HIGHLIGHTING AT LEAST 20% CHANCES FOR MINIMUM TEMPERATURE
FALLING BELOW THE 15TH PERCENTILE, AND A SLIGHT RISK OF MUCH BELOW NORMAL
TEMPERATURES REMAINS ISSUED FOR APR 9 OVER THE APPALACHIANS AND THE
MID-ATLANTIC. ANY FROST AND/OR FREEZES MAY ADVERSELY IMPACT EMERGING SPRING
VEGETATION IN THE HIGHLIGHTED REGION.
BY DAYS 9 AND 10 (APR 10-11), THE AFOREMENTIONED MEAN SURFACE HIGH REMAINS
FORECAST TO SHIFT INTO THE WESTERN ATLANTIC, ALLOWING FOR MORE RETURN FLOW FROM
THE GULF TO ADVECT AMPLE LOWER-LEVEL MOISTURE BACK INTO THE PLAINS AND
MISSISSIPPI VALLEY. BOTH THE GEFS AND ECMWF FAVOR HIGH PRECIPITATION WATER
ANOMALIES CONCENTRATED IN THE WARM SECTOR IN ADVANCE OF A DEVELOPING SURFACE
LOW IN THE LEE OF THE ROCKIES. COMPARED TO YESTERDAY, THERE IS BETTER AGREEMENT
IN THE UNCALIBRATED PRECIPITATION TOOLS WHICH BOTH NOW INDICATE 40-60% CHANCES
FOR 3-DAY AMOUNTS EXCEEDING AN INCH EXTENDING FROM THE SOUTHERN PLAINS INTO
PARTS OF THE LOWER MISSISSIPPI VALLEY, WITH 20% CHANCES FOR AMOUNTS EXCEEDING 2
INCHES FOCUSED OVER THE ARKLATEX REGION. GIVEN THE GOOD DAY-TO-DAY CONSISTENCY
IN THE TOOLS IN REGARDS TO THE TIMING OF THIS RISK LATE NEXT WEEK, AS WELL AS A
CONSENSUS ON THE HIGHER PROBABILITIES OF PRECIPITATION EXCEEDANCE, A MODERATE
RISK OF HEAVY PRECIPITATION IS ISSUED FROM THE SOUTHERN PLAINS TO THE MIDDLE
MISSISSIPPI VALLEY FOR APR 10-11. A SURROUNDING SLIGHT RISK AREA OF HEAVY
PRECIPITATION REMAINS ISSUED AND IS EXPANDED TO COVER MORE OF THE PLAINS AND
MISSISSIPPI VALLEY WHERE PETS DEPICT AT LEAST 20% CHANCES FOR 3-DAY AMOUNTS
EXCEEDING THE 85TH PERCENTILE, NOW VALID FOR APR 8-12. WITHIN THE HIGHLIGHTED
RISK AREAS, THERE IS A THREAT OF THUNDERSTORM ACTIVITY, PARTICULARLY ACROSS
PARTS OF OKLAHOMA AND TEXAS WHERE DETERMINISTIC SOLUTIONS SHOW THE RETURN OF
ELEVATED DEWPOINTS REACHING THE UPPER 60S AND LOWER 70S (DEG F), WITH A SHARP
DRYLINE GRADIENT TAKING SHAPE ACROSS THE SOUTHERN PLAINS.
ANY HEAVY PRECIPITATION REALIZED DURING EARLY WEEK-2 ACROSS THE PLAINS AND
MISSISSIPPI FOLLOWS A PARTICULARLY WET WEEK-1 OVER THIS PART OF THE COUNTRY
WHERE THE WEATHER PREDICTION CENTER (WPC) FORECASTS UPWARDS OF 1-4 INCHES THIS
WEEKEND AND THE NATIONAL WATER CENTER (NWC) DEPICTS A LIMITED FLOODING ZONE
FROM THE SOUTHERN PLAINS TO THE OHIO VALLEY IN THEIR OUTLOOK. GIVEN THAT NEARLY
A WEEK WILL HAVE PASSED FOR GROUND CONDITIONS TO DRY OUT BEFORE THIS HEAVY
PRECIPITATION RISK RETURNS THE FOLLOWING WEEKEND, NO CORRESPONDING FLOODING
HAZARDS ARE POSTED, HOWEVER LOCALIZED STREAMFLOW AND/OR URBAN FLOODING CANNOT
BE RULED OUT DURING WEEK-2.
AT THE BASE AND AHEAD OF THE MID-LEVEL TROUGHING OVER THE INTERIOR WEST, THERE
CONTINUES TO BE AN INCREASED RISK OF HIGH WINDS. DESPITE THE HIGHER RISK OF
HEAVY PRECIPITATION IN THE UPDATED OUTLOOK, THE WIND PETS ARE RATHER MUTED OVER
THE WESTERN AND CENTRAL CONUS WITH LITTLE TO NO SIGNAL FOR SPEEDS EXCEEDING THE
85TH PERCENTILE. WHILE CYCLONIC FLOW IS EVIDENT ACROSS THE WESTERN CONUS, THIS
PROBABLY STEMS FROM THE LACK OF AN AMPLIFYING TROUGH IN THE ENSEMBLE GUIDANCE,
WITH MUCH OF HEAVY PRECIPITATION RISK BEING MORE MOISTURE DRIVEN WITH SOME
DYNAMIC FORCING IN PLACE. STILL, THE UNCALIBRATED ECMWF AND GEFS CONTINUES TO
SHOW INCREASED CHANCES (20-40%) FOR WIND GUSTS EXCEEDING 34KTS (40 MPH) IN THE
PROXIMITY TO THE MEAN SURFACE LOW OVER THE PARTS OF THE PLAINS AND MISSISSIPPI
VALLEY, AND A SLIGHT RISK OF HIGH WINDS REMAINS ISSUED AND VALID APR 9-12. WITH
ANOMALOUS WARMTH FAVORED FOR THE PLAINS LEADING UP TO INCREASED WIND RISK, ANY
EPISODES OF HIGH WINDS ARE EXPECTED TO PROMOTE FIRE WEATHER THROUGH MUCH OF
THIS REGION INTO THE MIDDLE OF WEEK-2, PARTICULARLY IN AREAS NOT HAVING
REGISTERED ANY ABOVE-NORMAL RAINFALL IN RECENT WEEKS.
NO HAZARDS ARE ISSUED OVER ALASKA. WARMING TEMPERATURES ARE ALSO PREDOMINATELY
FAVORED TIED TO POSITIVE HEIGHT DEPARTURES EXPANDING EASTWARD FROM THE BERING
STRAIT INTO PARTS OF THE MAINLAND. THIS TEMPERATURE TREND FOLLOWS A PROLONGED
PERIOD OF BELOW NORMAL TEMPERATURES FELT THROUGHOUT THE STATE THIS WINTER, AS
ANY DRASTIC WARMUP COMBINED WITH RAPIDLY INCREASING SUN ANGLES OVER THE HIGHER
LATITUDES MAY ACCELERATE SPRINGTIME THAWS.
ACROSS HAWAII, PERSISTENT KONA LOW ACTIVITY BROUGHT HEAVY RAINFALL AND FLOODING
DURING MID-MARCH. ENSEMBLE GUIDANCE SHOWS THE RETURN OF AN APPROACHING
MID-LEVEL TROUGH TO THE NORTH OF THE ISLAND CHAIN, WHICH MAY TRIGGER ADDITIONAL
KONA LOW ACTIVITY AND RENEW THE RISK OF HEAVY PRECIPITATION DURING THE PERIOD.
PETS SHOW INCREASED CHANCES FOR 3-DAY AMOUNTS EXCEEDING THE 85TH PERCENTILE
THROUGH THE MIDDLE OF WEEK-2, HOWEVER THE HIGHEST PRECIPITATION AMOUNTS (3-DAY
AMOUNTS GREATER THAN 1 INCH) ARE FAVORED OFFSHORE AT THIS TIME. ANY HEAVY
PRECIPITATION DURING WEEK-2 MAY WORSEN ALREADY SATURATED GROUND CONDITIONS, AND
POSSIBLY TRIGGER FLOODING IN THE STATE.
FORECASTER: NICK NOVELLA
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