990
FXUS21 KWNC 191818
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 19 2025
SYNOPSIS: STRONG MID-LEVEL HIGH PRESSURE IS PREDICTED TO PEAK ACROSS THE
EASTERN CONTIGUOUS U.S. (CONUS) DURING WEEK-1 AND WEAKEN DURING WEEK-2.
INCREASED LIKELIHOOD OF EXTREME HEAT IS PREDICTED TO LINGER AT THE BEGINNING OF
THE PERIOD ACROSS THE NORTHEASTERN CONUS AND PARTS OF THE MID-ATLANTIC, OHIO
VALLEY, AND UPPER SOUTHEAST. THE REMNANTS OF HURRICANE ERICK ALONG WITH A
SURFACE FRONT EXTENDING FROM THE FOUR CORNERS REGION TO THE GREAT LAKES MAY
BRING LOCALIZED HEAVY PRECIPITATION TO PARTS OF THE FOUR CORNERS AND UPPER
MIDWEST EARLY WEEK-2. A TIGHT PRESSURE GRADIENT IS PREDICTED TO FORM OVER MUCH
OF COASTAL CALIFORNIA AND SOUTHERN OREGON, SUPPORTING EPISODES OF HIGH WINDS
ACROSS THESE AREAS FROM THE BEGINNING TO MIDDLE OF WEEK-2.
HAZARDS
MODERATE RISK OF EXTREME HEAT FOR PARTS OF THE GREAT LAKES, OHIO VALLEY,
NORTHEAST, AND MID-ATLANTIC, FRI, JUN 27.
SLIGHT RISK OF EXTREME HEAT FOR PORTIONS OF THE EASTERN CONUS, FRI-SAT, JUN
27-28.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE WESTERN GREAT LAKES, MIDDLE
MISSISSIPPI AND LOWER OHIO VALLEYS, FRI, JUN 27.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PARTS OF THE FOUR CORNERS REGION,
FRI-SAT, JUN 27-28.
SLIGHT RISK OF EPISODIC HIGH WINDS ACROSS COASTAL PORTIONS OF CALIFORNIA AND
SOUTHWESTERN OREGON, FRI-MON, JUN 27-JUL 1.
DETAILED SUMMARY
FOR SUNDAY JUNE 22 - THURSDAY JUNE 26:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR FRIDAY JUNE 27 - THURSDAY JULY 03: MULTIPLE ENSEMBLE MEANS SHOW AMPLIFIED
MID-LEVEL RIDGING ACROSS THE EASTERN CONUS PEAKING DURING WEEK-1 AND GRADUALLY
WEAKENING THROUGH WEEK-2. THIS TRANSLATES TO DECREASING EXTREME HEAT SIGNALS,
ALTHOUGH THE POTENTIAL FOR THIS HAZARD IS ANTICIPATED TO CONTINUE INTO AT LEAST
THE BEGINNING OF THE PERIOD. THE MODERATE RISK OF EXTREME HEAT IS SLIGHTLY
REDUCED IN COVERAGE, REMAINING ACROSS PARTS OF THE LOWER GREAT LAKES, OHIO
VALLEY, NORTHEAST, AND MID-ATLANTIC FOR JUN 27, WHEN THE PROBABILISTIC
EXTREMES TOOLS (PETS) SHOW AT LEAST A 40% CHANCE OF MAXIMUM TEMPERATURES
EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE. THE PET DERIVED FROM THE EUROPEAN
ENSEMBLES SHOWS OVER AN 80 PERCENT CHANCE FOR MAXIMUM TEMPERATURES TO EXCEED
THE 85TH CLIMATOLOGICAL PERCENTILE IN THE CENTRAL APPALACHIANS. A BROADER AREA
IS HIGHLIGHTED WITH A SLIGHT RISK (20 TO 40% CHANCE) ACROSS A LARGE PART OF THE
EASTERN CONUS, JUN 27 TO 28. ANTICIPATED HIGH DEWPOINTS ARE LIKELY TO SUPPORT
HEAT INDEX VALUES EXCEEDING TRIPLE DIGITS (DEG F) ACROSS PART OF THE
MID-ATLANTIC AND SOUTHEAST, WITH MID 90S (DEG F) ELSEWHERE IN THE MODERATE RISK
AREA ALONG THE EASTERN SEABOARD. DAILY MAXIMUM TEMPERATURES ARE NOT EXPECTED TO
REACH HAZARDS THRESHOLDS IN THE HIGHER ELEVATIONS OF THE APPALACHIANS.
MOST TOOLS INDICATE HOT WEATHER BUILDING INTO SOME PART OF THE CENTRAL AND/OR
EASTERN CONUS DURING THE MIDDLE OR END OF WEEK-2, BUT THERE IS GREAT
UNCERTAINTY REGARDING THE LOCATION, TIMING, AND MAGNITUDE OF ANY EXTREME HEAT.
NO HAZARD IS POSTED AT THIS TIME, BUT THE SITUATION WILL NEED TO BE MONITORED.
MANY TOOLS SHOW AN ENHANCED SIGNAL TODAY HIGHLIGHTING THE POSSIBILITY OF HEAT
BUILDING INTO THE INTERIOR NORTHWEST DURING THE MIDDLE TO END OF WEEK-2. THE
PETS ALL INDICATE SLIGHTLY ELEVATED CHANCES FOR TEMPERATURES TO EXCEED THE 85TH
PERCENTILE HERE, BUT THE SITUATION IS MARGINAL AND THERE HAS NOT BEEN ENOUGH
RUN-TO-RUN CONSISTENCY TO JUSTIFY POSTING ANY HAZARDS AT THIS TIME.
SIMILAR TO YESTERDAY, THE GEFS AND RECENT DETERMINISTIC GFS SOLUTIONS SHOW THE
POSSIBILITY OF SURFACE LOW FORMATION IN THE GULF BRINGING ENHANCED RAINFALL TO
PARTS OF THE CENTRAL OR WESTERN GULF COAST EARLY WEEK-2. A FEW ADDITIONAL
TOOLS, SUCH AS THE CANADIAN ENSEMBLES, ARE NOW INDICATING THIS POSSIBILITY.
HOWEVER, THERE REMAINS HIGH MODEL UNCERTAINTY REGARDING THE LOCATION AND
INTENSITY OF ANY HEAVY RAINFALL, SO NO ASSOCIATED RAINFALL HAZARDS ARE
DESIGNATED.
THE NATIONAL HURRICANE CENTER (NHC) INDICATED THAT HURRICANE ERICK WAS CENTERED
NEAR THE SOUTHWEST MEXICAN COAST AT 9AM CST, MOVING INLAND. THIS DISTURBANCE
COMBINED WITH POSSIBLE LOW FORMATION OVER BAJA CALIFORNIA AND THE SOUTHWEST MAY
BRING ENHANCED MOISTURE TO PARTS OF THE SOUTHWEST, POTENTIALLY TRIGGERING
LOCALIZED ENHANCED RAINFALL AND THUNDERSTORMS ACROSS THE AREA. A SLIGHT RISK OF
HEAVY PRECIPITATION IS DESIGNATED FOR PARTS OF THE SOUTHWEST AND EASTERN
PORTIONS OF THE FOUR CORNERS FOR JUN 27-28. THE DYNAMICAL MODEL OUTPUT IS NOT
PARTICULARLY BULLISH WITH THIS EVENT, BUT THEY ARE PROBABLY UNDERESTIMATING THE
STRENGTH OF THE MOIST TROPICAL INFLOW POISED TO MOVE INTO THE REGION, WHICH IS
TYPICAL IN SUCH SITUATIONS. ENHANCED RAINFALL COULD LEAD TO LOCALIZED FLASH
FLOODING.
MOISTURE FROM THE REMNANTS OF ERICK MAY CONTINUE NORTHEASTWARD, POSSIBLY
INTERACTING WITH A LINGERING SURFACE FRONT AND POTENTIAL LOW PRESSURE SYSTEM IN
THE UPPER MIDWEST. THIS SET-UP INCREASES THE ODDS FOR HEAVY RAINFALL ACROSS THE
MIDDLE MISSISSIPPI VALLEY AND ADJACENT GREAT LAKES REGION. THEREFORE, A SLIGHT
RISK OF HEAVY PRECIPITATION IS HIGHLIGHTED FOR THESE AREAS JUN 27. THE PETS ARE
IN GOOD AGREEMENT AND INDICATE AT LEAST A 20% CHANCE OF 3-DAY RAINFALL (JUN
27-29) EXCEEDING THE 85TH PERCENTILE AND ONE INCH, MOST OF WHICH WOULD LIKELY
FALL ON THE FIRST DAY OF WEEK-2. THIS RAIN WOULD BE FALLING ON SATURATED GROUND
WHERE SOME FLOODING HAS OCCURRED RECENTLY, POTENTIALLY TRIGGERING RENEWED
FLOODING THERE.
SURFACE HIGH PRESSURE OVER THE NORTHEAST PACIFIC ADJACENT TO SURFACE LOW
PRESSURE OVER THE SOUTHWESTERN CONUS MAY LEAD TO TIGHT PRESSURE GRADIENTS ALONG
PORTIONS OF THE WEST COAST. THIS PATTERN SUPPORTS A SLIGHT RISK OF EPISODIC
HIGH WINDS ACROSS MUCH OF THE CALIFORNIA COASTLINE NORTH OF THE TRANSVERSE
RANGES, AND ADJACENT SOUTHWESTERN OREGON. ONE OR MORE PERIODS OF HIGH WINDS ARE
POSSIBLE DURING JUN 27-JUL 1 BEFORE THE MID-LEVEL PATTERN CHANGES AND THE
PRESSURE GRADIENT RELAXES.
ICE-BOUND RIVERS ARE BEGINNING TO BREAK UP IN THE NORTH SLOPE OF ALASKA.
FLOODING IS POSSIBLE BY THE END OF WEEK-1 AND INTO WEEK-2 ACROSS MUCH OF THE
REGION AS A RESULT OF ICE JAMS, AUFEIS, SNOW MELT, AND ASSOCIATED FLOODING. A
FLOOD RISK IS NOT DESIGNATED TODAY DUE TO IMPROVING CONDITIONS ANTICIPATED
DURING WEEK-2.
FORECASTER: RICH TINKER
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