554
FXUS21 KWNC 181837
PMDTHR
US HAZARDS OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT JUNE 18 2025
SYNOPSIS: STRONG MID-LEVEL HIGH PRESSURE CONTINUES TO BE PREDICTED TO PEAK
ACROSS THE EASTERN CONTIGUOUS U.S. (CONUS) DURING WEEK-1 AND WEAKEN THROUGHOUT
WEEK-2. INCREASED LIKELIHOOD OF EXTREME HEAT IS PREDICTED TO LINGER AT THE
BEGINNING OF THE PERIOD ACROSS THE NORTHEASTERN CONUS INCLUDING PARTS OF THE
MID-ATLANTIC AND SOUTHEAST. REMNANTS OF HURRICANE ERICK AND SURFACE LOW
PRESSURE AND FRONTS EXTENDING FROM THE FOUR CORNERS REGION TO THE GREAT LAKES
MAY BRING LOCALIZED HEAVY PRECIPITATION TO PARTS OF THE FOUR CORNERS AND UPPER
MIDWEST AT THE BEGINNING OF THE PERIOD. A TIGHT PRESSURE GRADIENT IS PREDICTED
TO FORM OVER 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, MID-ATLANTIC, AND SOUTH CAROLINA, THU-FRI, JUN 26-27.
SLIGHT RISK OF EXTREME HEAT FOR PORTIONS OF THE EASTERN CONUS, THU-SAT, JUN
26-28.
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE UPPER AND MIDDLE
MISSISSIPPI AND OHIO VALLEYS, AND UPPER PENINSULA OF MICHIGAN, THU-FRI, JUN
26-27.
SLIGHT RISK OF HEAVY PRECIPITATION ACROSS PARTS OF THE FOUR CORNERS REGION,
THU-SAT, JUN 26-28.
SLIGHT RISK OF EPISODIC HIGH WINDS ACROSS COASTAL PORTIONS OF CALIFORNIA AND
SOUTHWESTERN OREGON, THU-MON, JUN 26-30.
DETAILED SUMMARY
FOR SATURDAY JUNE 21 - WEDNESDAY JUNE 25:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
FOR THURSDAY JUNE 26 - WEDNESDAY JULY 02: MULTIPLE ENSEMBLE MEANS SHOW
AMPLIFIED MID-LEVEL RIDGING ACROSS THE EASTERN CONUS PEAKING DURING WEEK-1 AND
GRADUALLY WEAKENING THROUGHOUT WEEK-2. THIS TRANSLATES TO DECREASING EXTREME
HEAT SIGNALS, ALTHOUGH THE POTENTIAL FOR THIS HAZARD IS ANTICIPATED TO CONTINUE
INTO THE BEGINNING OF THE PERIOD. THE HIGH RISK FOR HEAT IS DISCONTINUED IN
TODAY’S OUTLOOK. A MODERATE RISK OF EXTREME HEAT IS POSTED FOR PARTS OF THE
GREAT LAKES, OHIO VALLEY, NORTHEAST, MID-ATLANTIC, AND SOUTH CAROLINA, JUN 26
TO 27, WHERE THE PROBABILISTIC EXTREMES TOOLS (PETS) SHOW AT LEAST A 40% CHANCE
OF MAXIMUM TEMPERATURES EXCEEDING THE 85TH CLIMATOLOGICAL PERCENTILE,
CLIMATOLOGICALLY. A BROADER AREA IS HIGHLIGHTED WITH A SLIGHT RISK (20 TO 40%
CHANCE) ACROSS PARTS OF THE EASTERN CONUS, JUN 26 TO 28. ANTICIPATED HIGH
DEWPOINTS ARE LIKELY TO SUPPORT HEAT INDEX VALUES EXCEEDING TRIPLE DIGITS (DEG
F) ACROSS THE MID-ATLANTIC AND SOUTHEAST, WITH MID 90S (DEG F) ELSEWHERE IN THE
HIGHLIGHTED RISK AREAS. MINIMUM HEAT INDEX VALUES COULD REACH OR EXCEED 80 (DEG
F) IN SOME AREAS. LOWER TEMPERATURES ARE ANTICIPATED FOR HIGH ELEVATION AREAS.
THE GEFS AND RECENT DETERMINISTIC GFS SOLUTIONS SHOW THE POSSIBILITY OF SURFACE
LOW FORMATION IN THE GULF BRINGING ENHANCED RAINFALL TO PARTS OF THE GULF AT
THE BEGINNING OF WEEK-2. HOWEVER, DUE TO HIGH MODEL UNCERTAINTY, NO ASSOCIATED
RAINFALL HAZARDS ARE DESIGNATED AT THIS TIME.
THE NATIONAL HURRICANE CENTER (NHC) CURRENTLY INDICATES HURRICANE ERICK AS OF
9AM CST LOCATED OFFSHORE OF MEXICO. THIS DISTURBANCE COMBINED WITH POSSIBLE LOW
FORMATION OVER BAJA CALIFORNIA AND THE SOUTHWEST MAY BRING ENHANCED MOISTURE TO
PARTS OF THE SOUTHWEST WHICH COULD BRING LOCALIZED ENHANCED RAINFALL AND
THUNDERSTORMS TO THE AREA. A SLIGHT RISK OF HEAVY PRECIPITATION IS DESIGNATED
FOR PARTS OF THE SOUTHWEST AND EASTERN PORTIONS OF THE FOUR CORNERS, JUN 26-28.
ENHANCED RAINFALL COULD LEAD TO LOCALIZED FLASH FLOODING.
REMNANTS OF HURRICANE ERICK COMBINED WITH SURFACE LOW PRESSURE AND ASSOCIATED
FRONTS EXTENDING FROM THE FOUR CORNERS TO THE GREAT LAKES SUPPORTS INCREASED
CHANCES OF ENHANCED RAINFALL TO PARTS OF THE UPPER MIDWEST AT THE BEGINNING OF
THE PERIOD. A SLIGHT RISK OF HEAVY PRECIPITATION IS HIGHLIGHTED FOR PARTS OF
THE UPPER AND MIDDLE MISSISSIPPI AND OHIO VALLEYS, AND UPPER PENINSULA OF
MICHIGAN, JUN 26-27. THE PETS ARE IN GOOD AGREEMENT AND INDICATE AT LEAST A 20%
CHANCE OF 3-DAY RAINFALL (JUN 26-28) EXCEEDING THE 85TH PERCENTILE AND ONE INCH.
SURFACE HIGH PRESSURE OVER THE NORTHEAST PACIFIC ADJACENT TO SURFACE LOW
PRESSURE OVER THE SOUTHWESTERN CONUS MAY LEAD TO TIGHT PRESSURE GRADIENTS ALONG
THE COAST OF SOUTHERN OREGON AND CALIFORNIA. THIS PATTERN SUPPORTS A SLIGHT
RISK OF EPISODIC HIGH WINDS ACROSS COASTAL PORTIONS OF CALIFORNIA AND
SOUTHWESTERN OREGON, JUN 26-30.
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 FOR TODAY DUE TO CONDITIONS ANTICIPATED TO START
TO WANE DURING THE WEEK-2 PERIOD.
FORECASTER: MELISSA OU
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