313
FXUS01 KWBC 010729
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
328 AM EDT MON MAY 01 2023
VALID 12Z MON MAY 01 2023 - 12Z WED MAY 03 2023
...HEAVY RAIN TO CONTINUE ACROSS NORTHERN MAINE THROUGH MONDAY, AS
AREAS FURTHER SOUTH BEGIN TO CLEAR OUT...
...HEAVY SNOW WILL PERSIST ACROSS UPPER PENINSULA OF MICHIGAN
THROUGH EARLY WORK WEEK; WELL-BELOW-AVERAGE TEMPERATURES ACROSS
GREAT LAKES AND OHIO VALLEY THROUGH TUESDAY, SPREADING INTO
NORTHEAST AND MID-ATLANTIC ON WEDNESDAY...
...COOL AND UNSETTLED WEATHER SPREADS INTO THE WEST COAST, WHILE
WELL ABOVE AVERAGE TEMPERATURES CONTINUE ACROSS THE INTERMOUNTAIN
WEST, NORTHERN/CENTRAL ROCKIES, AND NORTHERN HIGH PLAINS...
AFTER WIDESPREAD HEAVY RAINFALL ACROSS THE MID-ATLANTIC AND
NORTHEAST THIS WEEKEND, WITH LOCALIZED AREAS RECEIVING AS MUCH AS
3-5" OF RAIN OVER THE PAST 48 HOURS, CONDITIONS ARE EXPECTED TO
SLOWLY IMPROVE FROM SOUTH TO NORTH AS THE HEAVIEST AXIS OF
PRECIPITATION PROGRESSES NORTHWARD INTO NORTHERN NEW ENGLAND
DURING THE MONDAY MORNING HOURS. ADDITIONAL RAINFALL AMOUNTS OF
1"+ WILL BE CONFINED TO NORTHERN MAINE, WITH SOME LOCALIZED HIGHER
ELEVATIONS FORECAST TO SEE UPWARDS OF 2" OVER THE NEXT 24 HOURS.
ALTHOUGH MUCH OF THE PRECIPITATION WILL HAVE ENDED BY LATE MONDAY,
CONDITIONS WILL REMAIN COOL AND DAMP, WITH SCATTERED SHOWERS
POSSIBLE THROUGH WEDNESDAY.
MEANWHILE, A HIGHLY ANOMALOUS UPPER-LOW, WHICH HAS BEEN PARTLY
RESPONSIBLE FOR HEAVY RAINFALL IN THE NORTHEAST, REMAINS NEARLY
STATIONARY OVER THE GREAT LAKES AND WILL CONTINUE TO LEAD TO MUCH
BELOW-AVERAGE TEMPERATURES AND LOCALIZED HEAVY SNOWFALL ACROSS
NORTHERN WISCONSIN AND THE UPPER PENINSULA (U.P.) OF MICHIGAN
THROUGH TUESDAY. SHORTWAVE ENERGY TRAVELING AROUND THE BASE OF THE
UPPER LOW WILL LEAD TO A CONTINUED RAPID DEEPENING OF A SURFACE
LOW OVER LAKE SUPERIOR AND THE ONTARIO PROVINCE LATE THROUGH
MONDAY, WITH SEVERAL LOCATIONS POTENTIALLY APPROACHING MAY MONTHLY
LOW-PRESSURE RECORDS.
THE ONGOING SNOWFALL IN THE NORTHERN GREAT LAKES REGION WILL
PERSIST THROUGH TUESDAY AS GUSTY, NORTHWESTERLY WINDS ON THE
BACKSIDE OF THE STRENGTHENING SURFACE LOW, IN CONJUNCTION WITH
COLD AIR ADVECTING SOUTHWARD AND OROGRAPHIC LIFTING, WILL LEAD TO
LOCALIZED ADDITIONAL TOTALS OF 1-2 FEET ACROSS HIGHER ELEVATIONS
OF THE INTERIOR U.P. OF MICHIGAN. GIVEN THE LATE-SEASON EVENT,
SURFACE TEMPERATURES HOVERING AROUND FREEZING WILL LEAD TO A VERY
HEAVY, WET SNOW, WHICH MAY RESULT IN DOWNED TREES AND POWERLINES.
THE SNOW WILL DIMINISH ON TUESDAY AS THE SYSTEM WEAKENS AND SLOWLY
PUSHES EASTWARD AS HIGH PRESSURE BUILDS IN. PORTIONS OF THE WEST
VIRGINIA APPALACHIANS MAY ALSO EXPERIENCE ACCUMULATING SNOW
THROUGH WEDNESDAY, WITH LOCALIZED WINTER STORM WARNINGS IN EFFECT.
FURTHERMORE, A BROADER AREA OF MUCH-BELOW-AVERAGE TEMPERATURES
(10-20 DEGREES F BELOW AVERAGE), ENCOMPASSING MUCH OF THE MIDWEST,
GREAT LAKES REGION, AND OHIO VALLEY, WILL BE POSSIBLE THROUGH
TUESDAY, AS DAYTIME HIGHS REMAIN IN THE LOW 40S AND NUMEROUS
LOCATIONS APPROACH OR BREAK DAILY RECORD LOW MAXIMUM TEMPERATURES.
AS THE UPPER LOW BEGINS TO PUSH NORTHEASTWARD, THE BELOW-AVERAGE
TEMPERATURES WILL SPILL INTO THE MID-ATLANTIC AND NORTHEAST, WITH
NIGHTTIME LOWS DIPPING INTO THE LOW 40S ACROSS NEARLY THE ENTIRETY
OF THE I-95 URBAN CORRIDOR.
FOR THE WESTERN U.S., A COOL AND UNSETTLED WEATHER PATTERN IS
CURRENTLY SPREADING INTO THE WEST COAST AS AN UPPER-LEVEL LOW IS
FORECAST TO SLIDE INTO THE REGION EARLY THIS WEEK. THIS WILL LEAD
TO SHOWERS AND HIGH-ELEVATION SNOW CHANCES, ALONG WITH
BELOW-AVERAGE TEMPERATURES. FURTHER INLAND, GUSTY SOUTHERLY WINDS
AND WELL ABOVE AVERAGE TEMPERATURES ARE ANTICIPATED FOR MUCH OF
THE INTERMOUNTAIN WEST, WITH WARM WEATHER ALSO SPREADING INTO THE
NORTHERN AND CENTRAL ROCKIES AND NORTHERN HIGH PLAINS. REGIONS
EXPERIENCING RIVER FLOODING DUE TO SNOW MELT ACROSS THE GREAT
BASIN CAN EXPECT MORE SIGNIFICANT SNOWMELT THIS WEEK.
ADDITIONALLY, SCATTERED SHOWER AND THUNDERSTORM CHANCES WILL
OVERSPREAD MUCH OF THE ROCKIES BY TUESDAY AS WELL.
RUSSELL/SNELL
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