256
FXUS02 KWBC 111908
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
207 PM EST SUN FEB 11 2024
VALID 12Z WED FEB 14 2024 - 12Z SUN FEB 18 2024
..OVERVIEW
EXPECT THREE MAIN WEATHER STORIES WILL DEVELOP OVER THE COMING
WEEK. THESE WILL INCLUDE INCREASINGLY WET PATTERNS FOR BOTH THE
SOUTH AND THE WEST COAST ALONG WITH THE USHERING OF AN ARCTIC
AIRMASS DOWN THROUGH THE CENTRAL TO EAST-CENTRAL STATES.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
BROAD COMPOSITE BLEND OF GENERALLY COMPATIBLE
GFS/ECMWF/UKMET/CANADIAN MODEL AND GEFS/ECMWF ENSEMBLE MEAN
GUIDANCE ALONG WITH THE 01 UTC NATIONAL BLEND OF MODELS (NBM) AND
WPC CONTINUITY. IN TERMS OF THE 01 UTC NBM, TEMPERATURES WERE
AGAIN REDUCED ACROSS MUCH OF THE NORTH-CENTRAL U.S. GIVEN THE
STRONG SIGNAL FOR AN ARCTIC SURFACE HIGH SETTLING LATER THIS WEEK.
THE UNLIKELY MUCH WARMER TEMPERATURES OF ESPECIALLY THE 06 UTC GFS
WERE MITIGATED WITH THIS MANUAL ADJUSTMENT. THE QPF WAS ALSO
RAISED ACROSS THE GENERAL VICINITY OF THE GREAT LAKES FRIDAY INTO
THE WEEKEND FROM THE NBM GIVEN THE OVERALL SIGNAL FOR LIGHT TO
MODERATE LAKE EFFECT SNOWS. OTHERWISE, NBM QPF SEEMS MOSTLY
REASONABLE AND CONSISTENT WITH GUIDANCE FORECAST SPREAD THAT HAS
NOW DECREASED ACROSS MUCH OF THE LOWER 48 AND ADJOINING WATERS,
BOLSTERING FORECAST CONFIDENCE TO A DEGREE. BLENDING THIS QPF WITH
SOME WPC CONTINUITY ACTED TO LESSEN RUN TO RUN PRODUCT VARIANCE.
..WEATHER/HAZARDS HIGHLIGHTS
A RELATIVELY QUIET PERIOD OF TIME IS EXPECTED ACROSS THE NATION ON
WEDNESDAY WITH MOST AREAS REMAINING DRY, ALBEIT WITH SOME TERRAIN
ENHANCED SNOW ACROSS THE NORTHERN INTERMOUNTAIN WEST/ROCKIES. NO
RISK AREAS ARE WARRANTED FOR THE WPC DAY 4/WEDNESDAY EXCESSIVE
RAINFALL OUTLOOK (ERO). LOOKING AHEAD TO THURSDAY AND FRIDAY, A
LOW PRESSURE SYSTEM IS EXPECTED TO DEVELOP OVER THE WESTERN GULF
IN ADVANCE OF APPROACHING SOUTHERN STREAM UPPER TROUGH ENERGY AND
ADVECT INCREASING MOISTURE NORTHWARD AND OVER A DEVELOPING WARM
FRONT, AND THIS WILL LIKELY RESULT IN WIDESPREAD SHOWERS AND
THUNDERSTORMS ACROSS SOUTHERN TEXAS AND INTO THE CENTRAL GULF
COAST REGION. THE GUIDANCE FAVORS SOUTH TEXAS FOR SOME LOCAL
DOWNPOURS STARTING OVERNIGHT THURSDAY, AND A MARGINAL RISK IS
SHOWN FOR THE DAY 5 ERO GIVEN INITIAL GROWING ENSEMBLE
PROBABILITIES. THE HEAVY RAINFALL SIGNATURE QUICKLY INCREASES
ACROSS THE SOUTH/SOUTHEAST FRIDAY AND NEXT WEEKEND AS A MAIN
FRONTAL LOW TRACKS EASTWARD ACROSS THE NORTHERN GULF OF MEXICO AND
FLORIDA UNDERNEATH A NORTHERN STREAM ARCTIC FRONT DIGGING DOWN
THROUGH THE CENTRAL THEN EASTERN STATES.
GUIDANCE HAS SLOWLY CONVERGED ON A MORE SIMILAR SOLUTION FOR THE
FOCUS AND ONSET OF ORGANIZED PRECIPITATION DEVELOPMENT INTO THE
WEST COAST IN AN EMERGING AND INCREASING WET PATTERN LATER THIS
WEEK AND LIKELY EXTENDING INTO NEXT WEEK TO MONITOR. MULTIPLE
PACIFIC SYSTEMS WILL STRUGGLE TO WORK EASTWARD, BUT DO SEEM NOW TO
ALLOW LEAD MOISTURE FUEL A MODERATE MOISTURE/RAIN FOCUS INTO THE
PACIFIC NORTHWEST/NORTHERN CALIFORNIA MID-LATE WEEK. ADDITIONAL
SYSTEM APPROACH SHOULD TEND TO ALLOW ACTIVITY TO REDEVELOP,
POSSIBLY WITH GREATER INTENSITY AND FOCUS GRADUALLY SOUTHWARD MORE
INTO CALIFORNIA INTO NEXT WEEKEND. EXPECT SNOW FOR THE HIGHER
TERRAIN, ESPECIALLY FOR THE SIERRA, WITH DIMINISHING SUPPORT
FARTHER INLAND ACROSS THE INTERMOUNTAIN WEST AND ROCKIES.
TEMPERATURES ARE EXPECTED TO BE GENERALLY 5 TO 15 DEGREES ABOVE
MID-FEBRUARY AVERAGES ACROSS MUCH OF THE MIDWEST REGION ON
WEDNESDAY AND THEN ACROSS HE MID-SOUTH AND OHIO VALLEY REGION ON
THURSDAY. MEANWHILE, A STRONG COLD FRONT DROPPING SOUTH FROM
WESTERN CANADA IS EXPECTED TO HERALD THE ARRIVAL OF AN ARCTIC
AIRMASS ACROSS THE NORTHERN PLAINS AND BRING A RETURN TO BELOW
AVERAGE TEMPERATURES FROM MONTANA TO THE DAKOTAS AND MINNESOTA
THROUGH THE END OF THE WEEK, PERHAPS UP TO 25 DEGREES BELOW
AVERAGE ACROSS PORTIONS OF MONTANA, BUT NOT AS COLD AS THE
PREVIOUS ARCTIC BLAST BACK IN MID-JANUARY. EXPECT A PERIOD
FAVORABLE FOR MODERATE UPSLOPE FETCH SNOWS WILL DIG DOWN THROUGH
THE NORTH-CENTRAL ROCKIES/PLAINS MID-LATER WEEK WITH FRONTAL
ADVANCE. COLD TEMPERATURES WITH THIS FRONT WILL GRADUALLY MODIFY
WITH SUBSEQUENT DIGGING THROUGH THE CENTRAL THE EASTERN U.S. LATER
WEEK INTO NEXT WEEKEND. ACCORDINGLY, THE PROSPECTS FOR LAKE EFFECT
SNOW ARE INCREASING TO CLOSE OUT THE WORK WEEK INTO NEXT WEEKEND
WITH THE MUCH COLDER AIRMASS CROSSING THE GREAT LAKES. THE
PROSPECT OF NORTHERN STREAM FLOW AMPLIFICATION NEXT WEEKEND AND
FRONTAL WAVE DEVELOPMENT OFFERS AT LEAST MODEST SNOW POTENTIAL
FROM THE OHIO VALLEY THROUGH THE NORTHEAST. HOWEVER, IT IS NOTABLE
THAT LATEST 12 UTC MODEL GUIDANCE IS MORE VARIABLE WITH FLOW
AMPLIFICATION.
HAMRICK/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 FORECAST, EXCESSIVE RAINFALL OUTLOOK,
WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY
MESSAGES 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
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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