000
FXUS01 KWBC 252033
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
432 PM EDT SAT MAY 25 2013
VALID 00Z SUN MAY 26 2013 - 00Z TUE MAY 28 2013
...SLIGHT RISK OF SEVERE THUNDERSTORM FOR A LARGE AREA OF THE
CENTRAL U.S. THROUGH MONDAY...
...FLASH FLOODING POSSIBLE OVER PORTIONS OF THE MIDWEST THROUGH
MONDAY...
...COLD AND WET CONDITIONS EXPECTED OVER NEW ENGLAND THROUGH
SUNDAY...
A STRONG LOW-PRESSURE SYSTEM ALONG THE NEW ENGLAND COAST THIS
AFTERNOON IS BRINGING WIDESPREAD PRECIPITATION AND ANOMALOUSLY
COLD TEMPERATURES TO THE NORTHEAST. THE LOW-PRESSURE SYSTEM IS
RATHER SLOW MOVING, SO THESE COLD AND WET CONDITIONS ARE EXPECTED
TO CONTINUE THROUGH MOST OF THE WEEKEND, PARTICULARLY ACROSS
NORTHERN NEW ENGLAND. AT THE HIGHER ELEVATIONS OF THE NORTHEAST
SUCH AS THE ADIRONDACKS IN NEW YORK AND THE GREEN MOUNTAINS IN
VERMONT, TEMPERATURES BE BE COLD ENOUGH FOR SNOW TO FALL.
ACCUMULATING SNOW IS POSSIBLE, PARTICULARLY AT THE HIGHER PEAKS.
THE PRECIPITATION WILL SLOWLY COME TO AN END FROM SOUTH TO NORTH
ON SUNDAY, BUT WILL PERSIST ACROSS NORTHERN MAINE INTO SUNDAY
EVENING.
ACROSS THE CENTRAL U.S., A STATIONARY FRONTAL BOUNDARY WILL SERVE
AS A FOCUS FOR MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS
THROUGH THE SHORT RANGE FORECAST PERIOD. A COMPLEX OF SHOWERS AND
THUNDERSTORMS IS FORECAST TO DEVELOP THIS EVENING ACROSS PORTIONS
OF THE DAKOTAS AND IOWA. THIS AREA OF SHOWERS AND THUNDERSTORMS
WILL MOVE SOUTHEASTWARD ALONG THE NORTH SIDE OF THE FRONT TOWARD
THE OHIO RIVER VALLEY BY SUNDAY AFTERNOON. ANOTHER AREA OF SHOWERS
AND THUNDERSTORMS WILL DEVELOP ACROSS THE NORTHERN PLAINS/UPPER
MIDWEST SUNDAY NIGHT. THERE IS A SLIGHT RISK OF EXCESSIVE
RAINFALL/FLASH FLOODING ACROSS MUCH OF THE MIDWEST THROUGH MONDAY
DUE TO THE POTENTIAL FOR A FEW ROUNDS OF HEAVY RAIN AND
THUNDERSTORMS. FARTHER SOUTH, MOISTURE FLOWING NORTHWARD FROM THE
GULF OF MEXICO WILL INTERACT WITH A DRY LINE EXTENDING FROM TEXAS
INTO THE CENTRAL HIGH PLAINS TO PRODUCE SCATTERED THUNDERSTORMS
EACH AFTERNOON. THE THREAT FOR THUNDERSTORMS ACROSS THE CENTRAL
AND NORTHERN PLAINS WILL INCREASE FURTHER LATE SUNDAY INTO MONDAY
AS A STORM SYSTEM CROSSING THE ROCKIES BEGINS TO EXIT INTO THE
PLAINS. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS
THESE AREAS. PLEASE REFER TO THE CONVECTIVE OUTLOOK PRODUCTS
ISSUED BY THE STORM PREDICTION CENTER FOR FURTHER INFORMATION ON
THE THREAT OF SEVERE WEATHER.
COOL AND UNSETTLED WEATHER WILL CONTINUE ACROSS PORTIONS OF THE
PACIFIC NORTHWEST AND THE NORTHERN ROCKIES AS A SERIES OF UPPER
DISTURBANCES MOVE THROUGH A BROAD UPPER TROUGH THAT IS FORECAST TO
REMAIN CENTERED OVER THE WESTERN U.S. THROUGH THE EARLY PART OF
NEXT WEEK. A WEAKENING PACIFIC LOW-PRESSURE SYSTEM WILL MOVE
ONSHORE IN THE PACIFIC NORTHWEST THIS EVENING. THE MOST WIDESPREAD
LIGHT TO MODERATE RAIN WILL FALL THROUGH TONIGHT ACROSS COASTAL
AREAS OF OREGON AND WASHINGTON, SPREADING INTO INTERIOR PORTIONS
OF THE SAME STATES BY SUNDAY AFTERNOON. SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE ACROSS MUCH OF THE NORTHWESTERN
U.S. AS THE PATTERN REMAINS GENERALLY UNSETTLED. A STRONGER
PACIFIC STORM SYSTEM WILL APPROACH THE NORTHWEST ON MONDAY,
BRINGING MORE WIDESPREAD RAIN TO THE REGION AGAIN.
RYAN
GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
$$
000
FXUS06 KWBC 251900
PMDMRD
PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SAT MAY 25 2013
THERE IS NO FORECASTER MESSAGE WRITTEN ON WEEKENDS
NOTES:
AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES.
IN THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT
ISSUED.
THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS
THE SAME AS THAT IN THE TABLES: A-ABOVE N-NEAR NORMAL B-BELOW
THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER
(ORANGE, "A"), COLDER (BLUE, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL AVERAGE VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "F"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING
WETTER (GREEN, "A"), DRIER (TAN, "B"), OR CLOSE TO (UNSHADED, "N")
HISTORICAL MEDIAN VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, "INCHES"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL
BE A GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY
EVEN A NORMAL (I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY
SEASONS. IN SUCH CASES A FORECAST OF NEAR NORMAL IS EFFECTIVELY A
FORECAST OF LITTLE OR NO PRECIPITATION.
THE CLIMATE PREDICTION CENTER USES 1981-2010 BASE PERIOD MEANS FOR
TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN
THE CLIMATE OUTLOOKS.
ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19880607 - 19910519 - 20020608 - 19660531 - 19990514
ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4)
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE
INCLUDE THE 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES:
19910519 - 19660531 - 19880607 - 19990513 - 19620522
6 TO 10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 31 - JUN 04, 2013
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON B N NRN CALIF B B
SRN CALIF B B IDAHO B N NEVADA B B
W MONTANA B A E MONTANA B A WYOMING B B
UTAH B B ARIZONA B B COLORADO A B
NEW MEXICO A B N DAKOTA B A S DAKOTA N A
NEBRASKA A A KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS N B W TEXAS A B
MINNESOTA N A IOWA A A MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A B MICHIGAN A A
INDIANA A A OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A N NEW YORK A A
VERMONT A B NEW HAMP A B MAINE A B
MASS A B CONN A B RHODE IS A B
PENN A N NEW JERSEY A B W VIRGINIA A B
MARYLAND A B DELAWARE A B VIRGINIA A B
N CAROLINA A B S CAROLINA A B GEORGIA A B
FL PNHDL A N FL PENIN B A AK N SLOPE A A
AK ALEUTIAN B N AK WESTERN A N AK INT BSN A A
AK S INT A N AK SO COAST N B AK PNHDL A A
8 TO 14 DAY OUTLOOK TABLE
OUTLOOK FOR JUN 02 - 08, 2013
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON N B NRN CALIF A B
SRN CALIF A B IDAHO A B NEVADA N B
W MONTANA A A E MONTANA A A WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS N B W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N NEW YORK A A
VERMONT A B NEW HAMP A B MAINE A N
MASS A B CONN A N RHODE IS A N
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A N DELAWARE A N VIRGINIA A A
N CAROLINA A A S CAROLINA A B GEORGIA A N
FL PNHDL A A FL PENIN B A AK N SLOPE A A
AK ALEUTIAN B B AK WESTERN N B AK INT BSN A N
AK S INT B N AK SO COAST B B AK PNHDL A A
LEGEND
TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN
A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN
B - BELOW B - BELOW
THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL
VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE
AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE.
FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS
PMDMRD.
$$
000
FXUS02 KWBC 251506
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1105 AM EDT SAT MAY 25 2013
VALID 12Z TUE MAY 28 2013 - 12Z SAT JUN 01 2013
...PATTERN OVERVIEW AND PREFERENCES...
GUIDANCE SHOWS REASONABLE LARGER SCALE AGREEMENT...WITH AN
AMPLIFIED MEAN TROUGH COVERING THE WRN STATES AND A STRENGTHENING
RIDGE SPREAD OVER THE EAST. HOWEVER THERE IS CONTINUED
UNCERTAINTY FOR SOME DETAILS WITHIN THE MEAN TROUGH AS WELL AS FOR
THE AMPLITUDE/ORIENTATION OF ERN CANADA/NERN CONUS FLOW ALOFT
THROUGH LATE NEXT WEEK. DETERMINISTIC MODEL RUNS STILL DISPLAY
ENOUGH SCATTER WITH VARIOUS FEATURES TO RECOMMEND EMPHASIZING THE
ENSEMBLE MEANS THROUGH THE MEDIUM RANGE PERIOD. PREFER A 60/20/20
BLEND OF 00 UTC ECMWF/GEFS/NAEFS ENSEMBLE MEANS DAYS 3-7
TUE-SAT...LEANING ON THE ECMWF MEAN THAT MAINTAINS BETTER RIDGE
INTEGRITY.
...GUIDANCE EVALUATION/UNCERTAINTY EVALUATION...
THE MAJORITY OF MODELS/ENSEMBLES EXPECT LEADING SHRTWV ENERGY TO
REACH THE WEST BY TUE AND LATER WORK INTO THE PLAINS WHILE
UPSTREAM ENERGY FLOWING INTO THE NORTHWEST CATCHES UP TO THE
LEADING ENERGY. THE BEST SOLUTION CLUSTERING HAS ENERGY
CONSOLIDATING INTO A CLOSED SYSTEM ALOFT OVER/NEAR THE NRN PLAINS
BY DAY 6 FRI.
RECENT ECMWF RUNS LEAN ON THE SLOWER/MORE AMPLIFIED SIDE OF
GUIDANCE WITH THE LEADING SHRTWV REACHING THE HIGH PLAINS BY THU.
GFS/GEFS MEANS REMAIN ON THE FASTER SIDE OF THE SPREAD WITH
UPSTREAM ENERGY. SUFFICIENT CONTINUITY EXISTS TO HAVE ABOVE
AVERAGE CONFIDENCE IN THE IDEA OF SFC LOW DEVELOPMENT OVER/NEAR
THE NRN PLAINS AROUND THU-FRI. THE UNCERTAINTY IN HOW MULTIPLE
PIECES OF SHRTWV ENERGY WILL INTERACT LEADS TO A DETERMINISTIC
FCST NOT MUCH STRONGER THAN THE ENSEMBLE MEANS FOR THE SFC LOW...
AND NOT AS WRAPPED UP AS THE ECMWF. MEANWHILE STRENGTH OF THE
DOWNSTREAM RIDGE AND OCCASIONALLY FAST GFS/GEFS BIASES WOULD FAVOR
LEANING A LITTLE SLOWER THAN RECENT GFS/GEFS MEANS FRI-SAT.
ULTIMATELY CANNOT FULLY DISCOUNT ANY SOLN AT THIS TIME IN LIGHT OF
TYPICAL DAYS 6-7 FCST ERRORS. BY THEN UPSTREAM...GEFS/ECMWF/CMC
MEANS ALSO INDICATE THAT PAC FLOW SHOULD BEGIN TO AMPLIFY IN
RESPONSE TO TROUGHING S OF THE ALEUTIANS...LEADING TO A SHARPER
TROUGH NEAR THE WEST COAST.
WELL DOWNSTREAM...THE MOST SIGNIFICANT ISSUE INVOLVES AMPLITUDE OF
ERN CANADA/NERN CONUS FLOW ALOFT DURING THE LATTER HALF OF THE
PERIOD AND RESULTING SFC FRONT POSN. WHILE RECENT ECMWF RUNS HAVE
BEEN FAIRLY AGGRESSIVE WITH TROUGH AMPLITUDE THUS BRINGING A SFC
FRONT RATHER FAR SWD...THE LATEST 00 UTC RUN HAS BACKED OFF SOME.
ON THE OTHER HAND GFS/GEFS RUNS KEEP HGTS HIGHER WITH A FARTHER
NWD FRONTAL ZONE. WITH INCREASED COMPATABILITY FROM 00 UTC
GUIDANCE...A BLENDED ENSEMBLE SOLUTION SEEMS REASONABLE.
...SENSIBLE WEATHER HIGHLIGHTS...
THE MEAN TROUGH ALOFT OVER THE WEST WILL SUPPORT UNSETTLED WEATHER
OVER THE WRN-CNTRL STATES... AND BELOW NORMAL TEMPS OVER THE WEST
EVENTUALLY WORKING SWD FROM THE NRN PLAINS. POTENTIAL STILL
EXISTS FOR SOME WRN PCPN TO EXTEND UNSEASONABLY FAR SWD. HGT
FALLS ALOFT REACHING THE CNTRL/SRN PLAINS MORE IN ERNEST AFTER
MIDWEEK AND MID LVL/SFC DEVELOPMENT FARTHER NWD LATE IN THE WEEK
MAY SUPPORT MULTIPLE AREAS OF MDT-HVY RNFL OVER/NEAR THE
PLAINS...INCLUDING SOME THREAT FOR SEVERE WEATHER. THE WARM FRONT
FCST TO LIFT ACROSS THE NERN QUADRANT OF THE LOWER 48 TUE ONWARD
IS ALSO EXPECTED TO BE CONVECTIVELY ACTIVE. AFTER PASSAGE OF THE
WARM FRONT EXPECT PERSISTENTLY ABOVE TO WELL ABOVE NORMAL TEMPS
OUT FROM THE CENTRAL US TO OVER MUCH OF THE EAST ALBEIT WITH SOME
UNCERTAINTY OVER THE NORTHEAST. FINALLY EXPECT A WET PATTERN OVER
SRN/ERN PARTS OF FL WITH MOIST ELY FLOW ON THE SRN SIDE OF
ATLC/ERN CONUS SFC HIGH PRESSURE.
SCHICHTEL
$$
000
FXUS01 KWBC 250838
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
437 AM EDT SAT MAY 25 2013
VALID 12Z SAT MAY 25 2013 - 12Z MON MAY 27 2013
...WET AND UNSEASONABLY COLD WEEKEND FOR THE NORTHEAST...
...SHOWERS AND THUNDERSTORMS WITH LOCALLY HEAVY RAINS FOR PORTIONS
OF THE PLAINS AND MISSISSIPPI VALLEY...
...UNSETTLED WEATHER CONTINUES IN THE PACIFIC NORTHWEST...
A STRONG AREA OF LOW PRESSURE WILL CHURN SLOWLY NORTH ALONG THE
NEW ENGLAND COAST OVER THE NEXT COUPLE OF DAYS, DELIVERING A
PROLONGED PERIOD OF WET WEATHER AND ANOMALOUSLY COLD TEMPERATURES
TO THE NORTHEAST THIS HOLIDAY WEEKEND. THIS AREA OF LOW PRESSURE,
CENTERED CURRENTLY ALONG THE SOUTHERN NEW ENGLAND COAST, WILL
TRACK SLOWLY TO THE NORTH, NOT REACHING THE CANADIAN MARITIME
PROVINCES UNTIL LATE SUNDAY. ATLANTIC MOISTURE THROWN AROUND THE
BACKSIDE OF THE SYSTEM WILL FUEL HEAVY PRECIPITATION ACCUMULATIONS
ACROSS PORTIONS OF NORTHERN NEW ENGLAND AND NEW YORK. SOME OF
THIS PRECIPITATION IS EXPECTED TO FALL IN THE FORM OF SNOW AS COLD
AIR POURS DOWN OUT OF CANADA, POSSIBLY RESULTING IN SIGNIFICANT
ACCUMULATIONS ACROSS SOME OF THE HIGHER PEAKS OF THE ADIRONDACKS,
GREEN AND WHITE MOUNTAINS. FURTHER TO THE SOUTH, UNSEASONABLY
COOL, BUT DRY CONDITIONS ARE EXPECTED TO HIGHLIGHT THE WEEKEND
ACROSS THE MID ATLANTIC AND SOUTHEAST.
ACROSS THE CENTRAL U.S., BROAD MOIST SOUTHERLY WINDS OUT OF THE
WESTERN GULF OF MEXICO ARE EXPECTED TO ENCOURAGE AT LEAST
SCATTERED SHOWERS AND THUNDERSTORMS, WITH ISOLATED HEAVY HEAVY
RAINS, ACROSS PORTIONS OF TEXAS AND OKLAHOMA BOTH DAYS. A BETTER
CHANCE FOR MORE ORGANIZED STORMS IS EXPECTED FURTHER TO THE NORTH
ALONG A SLOW MOVING FRONT STRETCHING FROM THE NORTHERN HIGH PLAINS
THROUGH THE MID MISSISSIPPI VALLEY. IN ADDITION TO THE STORMS
ALREADY FIRING ACROSS NEBRASKA INTO IOWA AND ILLINOIS, GULF
MOISTURE POOLING ALONG THE BOUNDARY INTERACTING WITH A STRING OF
UPPER LEVEL DISTURBANCES EMANATING FROM THE WEST MAY PRODUCE
ADDITIONAL ORGANIZED SHOWERS AND THUNDERSTORMS WITH HEAVY RAINS
LATER TODAY ACROSS PORTIONS OF THE NORTHERN HIGH PLAINS TO THE MID
MISSOURI AND MISSISSIPPI VALLEYS.
COOL AND UNSETTLED WEATHER WILL CONTINUE ACROSS PORTIONS OF THE
PACIFIC NORTHWEST AND THE NORTHERN ROCKIES AS A SERIES OF UPPER
DISTURBANCES MOVE THROUGH A BROAD UPPER TROUGH THAT IS FORECAST TO
REMAIN CENTERED OVER THE WESTERN U.S. THROUGH THE EARLY PART OF
NEXT WEEK. LOW PRESSURE LIFTING INTO WESTERN CANADA THIS MORNING
WILL BE REPLACED BY ANOTHER SYSTEM NEARING THE OREGON COAST LATER
TONIGHT. THIS IS EXPECTED TO PRODUCE SOME LIGHT TO MODERATE RAINS
CENTERED ACROSS WESTERN OREGON BEFORE PUSHING INLAND ON SUNDAY
WHILE YET ANOTHER SYSTEM APPROACHES THE COAST ON MEMORIAL DAY.
PEREIRA
GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
$$
000
FXUS02 KWBC 250640
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
239 AM EDT SAT MAY 25 2013
VALID 12Z TUE MAY 28 2013 - 12Z SAT JUN 01 2013
...OVERVIEW AND PREFERENCES...
GUIDANCE SHOWS REASONABLE AGREEMENT IN THE LARGE SCALE... WITH A
BROAD MEAN TROUGH COVERING THE WRN STATES AND A STRENGTHENING
RIDGE MOVING INTO THE EAST. HOWEVER THERE IS CONTINUED
UNCERTAINTY FOR SOME DETAILS WITHIN THE MEAN TROUGH AS WELL AS FOR
THE AMPLITUDE/ORIENTATION OF ERN CANADA/NERN CONUS FLOW ALOFT BY
THE LATTER HALF OF THE FCST. OPERATIONAL MODEL RUNS STILL DISPLAY
ENOUGH SCATTER WITH VARIOUS FEATURES TO RECOMMEND EMPHASIZING THE
ENSEMBLE MEANS THROUGH THE MEDIUM RANGE PERIOD. PREFER A 70/30
BLEND OF THE 12Z ECMWF/12Z GEFS MEANS DAYS 3-5 TUE-THU BASED ON
REASONABLE AGREEMENT OF THEIR SOLNS AND LONG TERM VERIFICATION.
THE 12Z ECMWF MEAN IS USED EXCLUSIVELY AFTER EARLY THU FOR ITS
INTERMEDIATE SOLN WITH NEW ENGLAND FRONTAL POSN ALTHOUGH THE 12Z
GEFS MEAN REMAINS AN ACCEPTABLE BLEND COMPONENT OVER THE WRN 2/3
OF THE CONUS.
...GUIDANCE EVALUATION...
THE MAJORITY OF MODELS/ENSEMBLES EXPECT LEADING SHRTWV ENERGY
REACHING THE WEST AS OF EARLY TUE TO CONTINUE INTO THE PLAINS
WHILE UPSTREAM ENERGY FLOWING INTO THE NORTHWEST CATCHES UP TO THE
LEADING ENERGY. THE BEST CLUSTERING OF SOLNS HAS THESE TWO
BUNDLES OF ENERGY CONSOLIDATING INTO A CLOSED SYSTEM ALOFT
OVER/NEAR THE NRN PLAINS BY DAY 6 FRI... SUPPORTING A FAIRLY
VIGOROUS SFC LOW. THIS SYSTEM SHOULD BEGIN TO PROGRESS EWD BY
NEXT SAT. OPERATIONAL ECMWF RUNS CONTINUE TO LEAN ON THE
SLOWER/MORE AMPLIFIED SIDE OF GUIDANCE WITH THE LEADING SHRTWV
REACHING THE HIGH PLAINS BY THU. ECMWF TRENDS HAVE BEEN GRADUALLY
FASTER OVER THE PAST COUPLE DAYS. THE 18Z GFS/GEFS MEAN ARE ON
THE FASTER SIDE OF THE SPREAD WITH UPSTREAM ENERGY AND FLATTER
WITH LEADING ENERGY... WITH THE 12Z GFS/GEFS MEAN CLOSER TO THE
OVERALL GUIDANCE MEAN. SUFFICIENT CONTINUITY EXISTS TO HAVE ABOVE
AVERAGE CONFIDENCE IN THE IDEA OF SFC LOW DEVELOPMENT OVER/NEAR
THE NRN PLAINS AROUND THU-FRI. THE UNCERTAINTY IN HOW MULTIPLE
PIECES OF SHRTWV ENERGY WILL INTERACT LEADS TO A DETERMINISTIC
FCST NOT MUCH STRONGER THAN THE ENSEMBLE MEANS FOR THE SFC LOW...
AND NOT AS WRAPPED UP AS THE 12Z ECMWF/CMC. MEANWHILE STRENGTH OF
THE DOWNSTREAM RIDGE AND OCCASIONALLY FAST GFS/GEFS BIASES WOULD
FAVOR LEANING A LITTLE SLOWER THAN RECENT GFS RUNS AND 18Z GEFS
MEAN DURING FRI-SAT. ULTIMATELY CANNOT FULLY DISCOUNT ANY SOLN AT
THIS TIME IN LIGHT OF TYPICAL DAYS 6-7 FCST ERRORS.
BY NEXT SAT THE LATEST GEFS/ECMWF/CMC MEANS INDICATE THAT FAST/LOW
AMPLITUDE PAC FLOW SHOULD BEGIN TO AMPLIFY IN RESPONSE TO
TROUGHING S OF THE ALEUTIANS... LEADING TO A SHARPER TROUGH NEAR
THE WEST COAST. THE 12Z GFS OFFERS THE CLOSEST MATCH TO THE MEANS
FOR THIS PART OF THE FCST. THE 12Z ECMWF BRINGS ITS ERN PAC RIDGE
EWD OF CONSENSUS WHILE THE 18Z GFS SOLN OF STALLING A CLOSED LOW
OFF THE PAC NW COAST WED ONWARD DOES NOT COMPARE WELL TO MOST
OTHER SOLNS EITHER.
FARTHER EWD THE MOST SIGNIFICANT ISSUE INVOLVES AMPLITUDE OF ERN
CANADA/NERN CONUS FLOW ALOFT DURING THE LATTER HALF OF THE PERIOD
AND RESULTING SFC FRONT POSN. THE PAST THREE ECMWF RUNS HAVE BEEN
FAIRLY AGGRESSIVE WITH TROUGH AMPLITUDE THUS BRINGING A SFC FRONT
RATHER FAR SWD. ON THE OTHER HAND GFS/GEFS RUNS KEEP HGTS A LOT
HIGHER WITH A MUCH FARTHER NWD FRONTAL ZONE. TELECONNECTIONS
RELATIVE TO THE WRN TROUGH AND AN ATLC RIDGE IN THE D+5 MEANS
SUGGEST LOWER NERN CONUS HGTS THAN FCST BY GFS/GEFS SOLNS BUT NOT
CONCLUSIVELY TO THE EXTENT OF THE ECMWF. THIS LEAVES THE 12Z
ECMWF MEAN AS THE BEST OPTION FOR FRONTAL PLACEMENT AT THIS TIME.
...SENSIBLE WEATHER HIGHLIGHTS...
THE MEAN TROUGH ALOFT OVER THE WEST WILL SUPPORT UNSETTLED WEATHER
OVER THE WRN-CNTRL STATES... AND BELOW NORMAL TEMPS OVER THE WEST
EVENTUALLY REACHING THE NRN PLAINS. POTENTIAL STILL EXISTS FOR
SOME WRN PCPN TO EXTEND UNSEASONABLY FAR SWD. THE SRN HALF OR 2/3
OF THE WEST SHOULD SEE A DRYING TREND BY FRI-SAT. HGT FALLS ALOFT
REACHING THE CNTRL/SRN PLAINS MID-PERIOD AND MID LVL/SFC
DEVELOPMENT FARTHER NWD LATE IN THE WEEK MAY SUPPORT MULTIPLE
AREAS OF MDT-HVY RNFL OVER/NEAR THE PLAINS. THE WARM FRONT FCST
TO LIFT ACROSS THE NERN QUADRANT OF THE LOWER 48 TUE ONWARD IS
ALSO EXPECTED TO BE CONVECTIVELY ACTIVE. AFTER PASSAGE OF THE
WARM FRONT EXPECT PERSISTENTLY ABOVE TO WELL ABOVE NORMAL TEMPS
OVER MUCH OF THE EAST ALBEIT WITH SOME UNCERTAINTY OVER THE
NORTHEAST. FINALLY EXPECT A WET PATTERN OVER SRN/ERN PARTS OF THE
FL PENINSULA DUE TO ELY FLOW ON THE SRN SIDE OF ATLC/ERN CONUS SFC
HIGH PRESSURE.
RAUSCH
$$
000
FXUS01 KWBC 242056
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
455 PM EDT FRI MAY 24 2013
VALID 00Z SAT MAY 25 2013 - 00Z MON MAY 27 2013
***COOL WITH SHOWERS OVER THE NORTHEAST STATES***
***SCATTERED SHOWERS AND STORMS OVER THE PLAINS***
***LARGE SCALE TROUGH WITH SHOWERS OUT WEST***
THE STRONG COLD FRONT THAT IS NOW CLEARING THE EAST COAST WILL
BRING A FRESH SURGE OF COOLER AND DRIER AIR TO THE EASTERN U.S.
FOR THE MEMORIAL DAY WEEKEND. THE COLDEST CONDITIONS ARE EXPECTED
FOR THE CENTRAL AND NORTHERN APPALACHIANS, WHERE FROST AND FREEZE
ADVISORIES AND WARNINGS ARE IN EFFECT. OVER NEW ENGLAND, THE
PRESENCE OF A SLOW-MOVING SURFACE LOW NEAR THE COAST WILL CREATE
SHOWERS AND BREEZY CONDITIONS THROUGH SUNDAY, THUS MAKING INDOOR
PLANS A WISE CHOICE.
OVER THE CENTRAL U.S. AND GREAT PLAINS, AN UPPER LEVEL RIDGE AND
RETURN FLOW FROM THE GULF OF MEXICO WILL ALLOW FOR WARMER
TEMPERATURES AND ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS.
A FEW ORGANIZED THUNDERSTORM COMPLEXES MAY BE ABLE TO DEVELOP,
WITH ISOLATED SEVERE WEATHER A POSSIBILITY. OUT WEST, BELOW
AVERAGE TEMPERATURES ARE ALSO EXPECTED IN THIS REGION WITH AN
UPPER LEVEL LOW AND INCREASED CLOUD COVER OVER THE PACIFIC
NORTHWEST AND INTO THE INTER-MOUNTAIN WEST. THE HIGHEST MOUNTAIN
RIDGES MAY EVEN GET SOME SNOW SHOWERS AT TIMES.
HAMRICK
GRAPHICS AVAILABLE AT WWW.WPC.NCEP.NOAA.GOV
$$
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