015
FXUS02 KWBC 291901
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
201 PM EST SUN JAN 29 2023
VALID 12Z WED FEB 01 2023 - 12Z SUN FEB 05 2023
...NOTABLE PRECIPITATION LIKELY FOR THE LATTER HALF OF THE WEEK
INCLUDING HEAVY RAIN IN THE SOUTH-CENTRAL TO SOUTHEASTERN U.S.
WITH FREEZING RAIN/SNOW ON THE NORTHERN SIDE...
...DANGEROUSLY COLD TEMPERATURES AND WIND CHILLS ARE FORECAST
ACROSS THE NORTHERN PLAINS/UPPER MIDWEST AND INTO THE NORTHEAST AT
TIMES THROUGH THE WEEK...
..OVERVIEW
GUIDANCE HAS BEEN OVERALL CONSISTENT WITH DEPICTION OF AN OVERALL
FLOW PATTERN THAT OFFERS PERIODS OF TROUGHING ARE LIKELY THROUGH
MUCH OF THE NORTHERN U.S. THIS WEEK EXTENDING FROM A PERSISTENT
HUDSON BAY CLOSED LOW, LEADING TO COLDER THAN AVERAGE TEMPERATURES
FOR MUCH OF THE NORTHERN TIER. THE COLD TEMPERATURES AND WIND
CHILLS COULD BE MOST HAZARDOUS FOR THE NORTH-CENTRAL U.S. THROUGH
AROUND FRIDAY, WITH SIGNIFICANT COLD EXTENDING INTO THE NORTHEAST
BY LATE WEEK. MEANWHILE A RIDGE/UPPER HIGH OVER CUBA DURING MUCH
OF THE WEEK SHOULD KEEP THE SOUTHEAST WARMER THAN NORMAL. BETWEEN
THESE UPPER-LEVEL FEATURES AND TEMPERATURE REGIMES, EXPECT ACTIVE
WEATHER AS A SOUTHERN STREAM UPPER TROUGH/LOW EJECTS FROM THE
SOUTHWEST AND TRACKS ACROSS THE CENTRAL/SOUTHERN TIER OF THE
CONUS. THIS COMBINED WITH A COUPLE WAVY FRONTS ALONG WITH PERIODS
OF GULF INFLOW WILL SUPPORT A COUPLE OF SIGNIFICANT PRECIPITATION
EVENTS WITH HEAVY RAIN AND POSSIBLE FLOODING TO THE
SOUTH/SOUTHEAST AND WINTRY WEATHER IN THE COLDER AIR. LATER IN THE
WEEK, THE WEST COAST MAY SEE INCREASING PRECIPITATION CHANCES WITH
THE APPROACH OF AN EASTERN PACIFIC UPPER TROUGHING TO POTENTIALLY
INCLUDE AN AMPLIFIED UPPER LOW/TROUGH AND DEEPENED SURFACE SYSTEM
APPROACH OVER NEXT WEEKEND TO MONITOR.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
COMPOSITE BLEND OF REASONABLY CLUSTERED PATTERN EVOLUTION GUIDANCE
FROM THE 06 UTC GFS/GEFS, THE 00 UTC ECMWF/UKMET/CANADIAN AND THE
ECMWF ENSEMBLE MEAN THROUGH MEDIUM RANGE TIME SCALES IN A PATTERN
WITH OVERALL ABOVE NORMAL PREDICTABILITY AND DECENT ENSEMBLE, WPC
CONTINUITY AND NATIONAL BLEND OF MODELS SUPPORT. DESPITE OVERALL
FLOW SIMILARITIES, THE BROAD COMPOSITE WAS USED TO MITIGATE,
CONSISTENT WITH UNCERTAINTY, AMPLE FLOW EMBEDDED SHORTWAVE TIMING
AND FOCUS DIFFERENCES THAT GROW OVER TIME. A COMPOSITE OF LATEST
12 UTC MODELS AND ENSEMBLES REMAINS IN LINE WITH THIS FORECAST
STRATEGY AND MAINTAINS GOOD WPC PRODUCT CONTINUITY.
..WEATHER/HAZARD HIGHLIGHTS
THE SOUTHERN STREAM UPPER TROUGH/LOW TRACKING ACROSS THE SOUTHERN
U.S. AND THE BROADER NORTHERN STREAM TROUGH WILL PROVIDE SUPPORT
FOR FRONTAL BOUNDARIES WITH WAVES OF LOW PRESSURE THROUGH THE
SOUTH-CENTRAL TO SOUTHEASTERN U.S., WHICH COMBINED WITH GULF
MOISTURE STREAMING IN WILL LEAD TO WIDESPREAD PRECIPITATION. ON
THE SOUTHERN SIDE LOCALLY HEAVY RAIN IS EXPECTED, WHICH COULD
CAUSE LOCALIZED FLOODING ESPECIALLY AT TIMES WHEN THERE IS
SUFFICIENT INSTABILITY FOR HIGHER RAIN RATES. AT THIS TIME SLIGHT
RISKS ARE IN PLACE IN WPC'S EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK FOR BOTH WEDNESDAY FROM EASTERN TEXAS INTO THE LOWER
MISSISSIPPI VALLEY AND DAY 5/THURSDAY STRETCHING INTO THE
SOUTHEAST GIVEN GOOD UPPER-LEVEL SUPPORT, NAMELY EXCELLENT
DIFLUENCE/DIVERGENCE IN THE RIGHT ENTRANCE REGION OF THE JET, AS
IT TRACKS EASTWARD. THEN ON THE NORTHERN SIDE OF THE PRECIPITATION
CHANCES, THERE IS POTENTIAL FOR SNOW ACROSS PARTS OF THE SOUTHERN
HALF OF THE PLAINS AND MISSISSIPPI VALLEY INTO THE OHIO/TENNESSEE
VALLEYS AND THE MID-ATLANTIC AT TIMES, BUT LOW CONFIDENCE
CONTINUES IN THE SPECIFICS, EVEN WITH MODEST AMOUNTS. THIS IS ALSO
A PATTERN THAT COULD SUPPORT FREEZING RAIN WITH ICE ACCUMULATIONS
WITH THE COLD AIR IN PLACE AT THE SURFACE AND POTENTIAL FOR WARM
MOIST AIR TO FLOW OVERTOP IT. THE PLACEMENT OF HEAVIEST RAIN,
FREEZING RAIN, AND SNOW ALL REMAIN IN QUESTION AS SMALL-SCALE
DETAILS LIKE SURFACE FRONTAL POSITIONS AND LATE WEEK SHORTWAVE
SPECIFICS REMAIN UNCERTAIN. DRIER CONDITIONS ARE LIKELY FOR THE
EAST BY SATURDAY. ELSEWHERE, PERIODS OF LAKE EFFECT SNOW ARE
POSSIBLE TO THE LEE OF THE NORTHERN/EASTERN GREAT LAKES. THE WEST
COAST COULD SEE INCREASING PRECIPITATION CHANCES BY LATER IN THE
WEEK BUT WITH UNCERTAINTY OVER THE SOUTHWARD EXTENT AND AMOUNTS.
CURRENTLY THE BEST POTENTIAL FOR AT LEAST SOME RAIN/MOUNTAIN SNOW
IS OVER THE PACIFIC NORTHWEST WITH MOISTURE POSSIBLY EXTENDING AS
FAR SOUTH AS NORTHERN CALIFORNIA, AND AS FAR EAST AS THE NORTHERN
ROCKIES.
VERY COLD CONDITIONS OVER THE NORTH-CENTRAL U.S. DURING THE SHORT
RANGE PERIOD COULD CONTINUE INTO THE LATTER PART OF THE WEEK,
UNDERNEATH INSTANCES OF COLD UPPER TROUGHING. GUIDANCE HAS
FLUCTUATED WITH THE FULL EXTENT OF THE COLD INTRUSION, BUT THE
OVERALL SIGNAL IS STRONG. HIGHS IN THE SINGLE DIGITS OR EVEN BELOW
ZERO ARE POSSIBLE IN THE DAKOTAS INTO MINNESOTA WHILE BITTERLY
COLD LOWS COMBINED WITH WIND WILL PRODUCE DANGEROUS WIND CHILLS.
MUCH BELOW NORMAL TEMPERATURES THEN SHIFT INTO THE NORTHEAST BY
LATE WEEK, WITH THE POSSIBILITY OF HIGHS BELOW ZERO IN NORTHERN
NEW ENGLAND BY SATURDAY. SOME RECORD VALUES ARE POSSIBLE OVER THE
NORTHEAST. TEMPERATURES ARE EXPECTED TO BE GENERALLY BELOW NORMAL
ACROSS MUCH OF THE INTERIOR WEST AND CENTRAL U.S. AROUND MIDWEEK
WITH GRADUAL MODERATION THEREAFTER. MEANWHILE THE FAR SOUTHEAST
AND FLORIDA PENINSULA SHOULD SEE THE MOST CONSISTENT ABOVE AVERAGE
TEMPERATURES, WITH HIGHS 10-15F ABOVE AVERAGE AND PLUS 10-20F
ANOMALIES FOR LOWS BEFORE A COOLER TREND NEXT WEEKEND.
TATE/SCHICHTEL
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION, EXPERIMENTAL EXCESSIVE RAINFALL
OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES AND HEAT INDICES ARE
AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page