Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 05/12/13
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
135 AM CDT FRI MAY 10 2013
.UPDATE...
UPDATED FOR THE 06Z AVIATION DISCUSSION BELOW.
&&
.AVIATION...
SHOWERS HAVE MOVED EAST OF MOST CENTRAL AND SOUTHERN SITES...BUT
EXPECT A NEW WAVE OF SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE
NEXT FEW HOURS AND AFFECT TERMINAL FROM KLIT SOUTHWARD.
MEANWHILE...A BAND OF SHRA/TSRA WILL MOVE FROM KFYV EAST TO KHRO
AND KBPK. EXPECT AT LEAST MVFR CONDITIONS FOR 3-4 HOURS WITH
PREVAILING SHRA AND OCCASIONAL TSRA. WOULD NOT BE SURPRISED TO SEE
CONDITIONS DROP TO IFR LEVELS...ESPECIALLY VSBY.
SHOWERS AND THUNDERSTORMS WILL CLEAR ALL TERMINALS BY 10-12Z OR
SO...WITH VFR CONDITIONS RETURNING THEREAFTER. MORE STORMS MAY
FIRE IN SOUTHEAST ARKANSAS THIS EVENING AND HAVE VCSH MENTIONED
FROM 00Z SAT ONWARD AT KPBF AND KLLQ TO ACCOUNT FOR THIS.
&&
.PREV DISCUSSION... /ISSUED 858 PM CDT THU MAY 9 2013/
UPDATE...
CONVECTION CONTINUES OVER THE SOUTH AT THIS TIME AS UPPER LEVEL
ENERGY APPROACHES FROM TEXAS. OTHER WEAKER CONVECTION ACROSS THE
NORTH IS WORKING OVER THE SAME GENERAL AREA THAT SAW SOME
THUNDERSTORMS THIS MORNING. ACTIVITY HAS BEEN SLOWLY WEAKENING BUT
POTENTIAL REMAINS FOR SOME LARGER HAIL THROUGH THE NIGHT.
SOME STORMS LIKELY WILL PRODUCE BRIEF HEAVY DOWNPOURS BUT NO
HEADLINES ARE ANTICIPATED AT THIS TIME. AFOREMENTIONED WAVE STILL
OVER NORTHEAST TEXAS AND HAS TO ROTATE THROUGH THE STATE TONIGHT
AND WILL KEEP POPS ON THE HIGH SIDE AS A RESULT.
ATTENTION WILL ALSO DIRECTED TOWARDS THE AFOREMENTIONED COLD
FRONT CURRENTLY STRETCHING FROM CENTRAL OKLAHOMA THROUGH CENTRAL
MISSOURI. THE BOUNDARY WILL BE A SLOW MOVER AND WILL ONLY REACH
FAR NORTHWEST ARKANSAS BY MORNING KEEPING POPS ELEVATED ACROSS
THIS PART OF THE STATE AS WELL.
EVENING UPDATE WILL BE TO REWORK POPS AND QPF BASED ON CURRENT
RADAR TRENDS AND A QUICK PEEK AT THE NEW NAM AND THE HRRR MODELS.
ALL UPDATES OUT.
PREV DISCUSSION... /ISSUED 305 PM CDT THU MAY 9 2013/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
CONVECTION THAT AFFECTED PARTS OF THE AREA THIS MRNG...HAD SHIFTED E
OF THE REGION BY MIDDAY. SUBSIDENCE BEHIND THIS ACTIVITY HAS LIMITED
ADDITIONAL FORMATION ACRS AR THRU MID AFTN. IT ALSO ALLOWED CLOUDS
TO DCRS OVR MUCH OF NRN AND ERN AR...WITH MID AFTN TEMPS IN THE UPR
70S TO LOWER 80S. INCRSG CLOUDS OVR SWRN AR HELD READINGS IN THE
LOWER AND MID 70S. WL KEEP MINIMAL POPS OVR MOST OF THE FA EARLY
THIS EVENING.
MEANWHILE...A COMPLEX OF STORMS CONTD TO ORGANIZE ACRS CNTRL/ERN TX
THIS AFTN...ASSOCD WITH ANOTHER UPR LVL WV MOVG ACRS THE SRN PLAINS.
AN ADDITIONAL CLUSTER OF STORMS HAS FORMED ALONG THE RED RVR IN SERN
OK. EXPECT SOME THIS ACTIVITY TO AFFECT WRN AR TOWARD SUNSET.
ADDITIONAL CONVECTION WL FORM TNGT AS THE AFOREMENTIONED UPR IMPULSE
TRACKS INTO AR...AND ALONG A SLOW MOVG CDFNT APCHG FM THE CNTRL
PLAINS. CURRENT DATA SUGGESTS THE BNDRY WL BE ALONG THE I-44
CORRIDOR EARLY FRI MRNG. CANNOT RULE OUT A FEW STRONG/SVR STORMS
TNGT...WITH LARGE HAIL AND WINDS THE MAIN CONCERNS.
APPEARS WE WL SEE A LULL IN THE RAINFALL LATER FRI MRNG/EARLY AFTN
AS THE FIRST ROUND OF STORMS WORKS E OF THE AREA. THE CDFNT WL CONT
TO DRIFT EVER SO SLOLY SEWD INTO CNTRL AR LATER ON FRI AS THE BNDRY
INITIALLY ENCOUNTERS SWLY FLOW ALOFT. SCTD SHRA/TSRA WL BE POSSIBLE
AHEAD OF THE FNT INTO FRI NGT. RAIN CHCS WL DCRS FM THE NW AS THE
NGT PROGRESSES AND THE FNT SHIFTS SE OF AR.
DRIER CONDS RETURN FOR SAT WITH TEMPS CLOSE TO NORMAL FOR THIS TIME
OF YEAR. A SECONDARY CDFNT WL SWEEP SWD THRU AR SAT NGT...FOLLOWED
BY COOLER AND MUCH DRIER AIR. AN UPR LVL IMPULSE IS PROGGED TO DROP
SEWD INTO THE AREA LATER SUN NGT...BRINGING AN INCRS IN CLOUDS. WL
KEEP THE FCST DRY ATTM AND MONITOR MODEL TRENDS IN THE COMING DAYS
FOR THE POSSIBLE INCLUSION OF SMALL RAIN CHCS.
LONG TERM...MONDAY THROUGH THURSDAY
THE EXTENDED FORECAST STARTS WITH A LARGE SURFACE HIGH PRESSURE
SYSTEM OVER THE CENTRAL U.S...WHILE A LARGE AND BROAD UPPER TROUGH
OVER THE NE TO SE U.S. WEATHER WILL BE DRY WITH JUST A BIT COOLER
TEMPS TO START. MONDAY THE SURFACE HIGH PRESSURE CENTERS OVER THE
SOUTHEASTERN PLAINS...AS THE LARGE UPPER TROUGH OVER THE EAST COAST
MOVES A BIT MORE EAST. THIS WILL BRING DRY WEATHER AND TEMPS CLOSER
TO NORMAL VALUES. ON TUESDAY CONTINUED DRY WITH WARMING TEMPS AS THE
SURFACE HIGH PRESSURE HAS MOVED OFF TO THE EAST OF AR. ON WEDNESDAY
MODELS ARE DEPICTING AN UPPER SYSTEM OVER THE SOUTHERN PLAINS...AND
WITH RETURN FLOW TO THE AREA...SOME CONVECTION SHOULD BE SEEN MAINLY
OVER TEXAS. THE FORECAST WILL REMAIN DRY OVER AR WITH WARMER TEMPS.
LATER WEDNESDAY NIGHT AND THURSDAY...A SLIGHT CHANCE OF CONVECTION
IS BACK IN THE FORECAST AS THIS UPPER SYSTEM SLOWLY MOVES EAST AND
AFFECTS AR. TEMPS WILL REMAIN WARM WEDNESDAY AND THURSDAY. OVERALL
CONFIDENCE IS AVERAGE WITH MODEL TRENDS BUT TIMING COULD CHANGE IN
FUTURE MODEL RUNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 76 54 73 47 / 40 20 10 10
CAMDEN AR 81 60 76 51 / 50 30 20 10
HARRISON AR 70 51 70 45 / 30 10 10 10
HOT SPRINGS AR 79 58 75 52 / 50 20 10 10
LITTLE ROCK AR 80 58 75 54 / 50 20 10 10
MONTICELLO AR 81 62 77 53 / 60 30 20 10
MOUNT IDA AR 77 54 75 48 / 50 20 10 10
MOUNTAIN HOME AR 72 51 72 45 / 30 10 10 10
NEWPORT AR 77 55 73 50 / 50 20 10 10
PINE BLUFF AR 80 61 75 53 / 50 30 20 10
RUSSELLVILLE AR 79 52 75 46 / 40 20 10 10
SEARCY AR 79 56 74 48 / 50 20 10 10
STUTTGART AR 79 59 73 53 / 50 20 20 10
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...64
AREA FORECAST DISCUSSION
NWS TUCSON AZ
230 AM MST FRI MAY 10 2013
.SYNOPSIS...A LOW PRESSURE SYSTEM NEAR THE AREA WILL HELP BRING A
CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS THROUGH SATURDAY.
DRIER WITH A STRONG HEATING TREND EARLY IN THE NEW WEEK...HOWEVER
STILL A FEW ISOLATED THUNDERSTORMS NEAR THE EASTERN MOUNTAINS.
&&
.DISCUSSION...RESIDUAL ENERGY SAGGING BACK INTO THE DESERT SOUTHWEST
FOR ANOTHER COUPLE OF DAYS WITH WHAT`S LEFT OF THE ENERGY SHIFTING
THROUGH NORTHERN AND CENTRAL SONORA OVER THE NEXT 36 HOURS. SOME MID
LEVEL MOISTURE IN PLACE AS EVIDENCED BY DEBRIS CLOUD WITH SLOW
INCREASE IN BLENDED TOTAL PRECIPITABLE WATER TRENDS FROM .45 TO .6
ON SATELLITE SOUNDER ESTIMATES. SHOULD BE ENOUGH FOR A JUMP IN
CONVECTION THIS AFTERNOON WITH SUFFICIENT CAPE AND FLOW FOR SOME
STORMS TO SPREAD INTO VALLEYS THIS AFTERNOON. DRY MICROBURSTS A
POTENTIAL CONCERN WITH SOME ORGANIZED BLOWING DUST POSSIBLE. A CLOSE
LOOK AT THE 12Z SOUNDING AND LATEST HRRR TRENDS AS WE CONTINUE TO
FINE TUNE CURRENT FORECAST ALREADY WELL ABOVE CLIMO CONVECTION.
ECMWF AND NAMDNG5 TRENDS SHOWS THE LOW STALLING AND FILLING THROUGH
CHIHUAHUA AND SONORA OVER THE WEEKEND WITH A FEW STORMS AROUND
SOUTHEAST ARIZONA SATURDAY. AS THE REMAINS CONTINUE TO SLOWLY FILL
IT SHOULD SHEAR THROUGH AS IT REGAINS MODEST HIGHER LATITUDE SUPPORT
BY TUESDAY OR WEDNESDAY. NEARLY ZONAL GEOMETRY BUT NET GAIN IN
HEIGHT AND THICKNESS TRENDS ALONG WITH A DRYING TREND SHOULD ALLOW
DAYTIME HIGHS 5 TO 8 DEGREES ABOVE CLIMO THE SECOND HALF OF NEXT
WEEK.
&&
.AVIATION...SKC-SCT150. AFT 17Z...SCT TO LCLY BKN 6-10KFT AGL MNLY E
AND S OF KTUS. ISOLD-SCT TSRA/-SHRA DVLPG OVER THE MTNS WITH SOME
STORMS MOVG W-SW INTO THE VALLEYS. BRIEF WIND GUSTS UP TO 40 KTS MAY
OCCUR NEAR TSTMS. SFC WIND THIS AFTERNOON WLY/NWLY 10-15 KTS WITH
GUSTS TO NEAR 25 KTS...STRONGEST E AND S OF KTUS.
OTHERWISE...SURFACE WIND GENERALLY LESS THAN 10 KTS. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...THERE IS A CHANCE OF AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS ESPECIALLY EAST OF TUCSON THROUGH SATURDAY. THERE
IS THE POTENTIAL FOR GUSTY WINDS ASSOCIATED WITH THUNDERSTORMS...
PARTICULARLY THIS AFTERNOON AND EVENING...AS A LOW PRESSURE SYSTEM
MOVES SOUTH INTO SONORA MEXICO. FIELD CREWS ARE ENCOURAGED TO
MONITOR THE LATEST FORECASTS REGARDING THIS SCENARIO. OTHERWISE...
GUSTY EAST TO SOUTHEAST WINDS WILL OCCUR SATURDAY. CRITICAL FIRE
WEATHER THRESHOLDS ARE NOT FORECAST TO BE MET AT THIS TIME.
THEREAFTER...EXPECT DRY CONDITIONS WITH ABOVE NORMAL DAYTIME
TEMPERATURES SUNDAY THROUGH THURSDAY.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
MEYER/GLUECK
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1113 AM MDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 848 AM MDT FRI MAY 10 2013
UPDATED FORECAST GRIDS AND ZONES TO REFLECT CURRENT CONDITIONS...WITH
GENERALLY CLEAR SKIES ACROSS THE CWA...AND A BAND OF MID LEVEL CLOUDS
MOVING SWD ACROSS THE PALMER DVD AND INTO N EL PASO. ALSO REDUCED
POPS AND TAPERED PRECIP CHANCES TOWARDS LATER THIS AFTERNOON. HRRR IDEA
OF BRINGING SCT SHOWERS ACROSS THE PLAINS BY MID TO LATE AFTERNOON LOOKS
REASONABLE...ALONG WITH BETTER COVERAGE ACROSS THE MTS. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI MAY 10 2013
THE UPPER TROF AXIS WILL CONTINUE TO SHIFT SOUTH OF THE AREA TODAY
WITH SOME TRAILING ENERGY ACROSS SRN WY/NRN CO SINKING ACROSS SE CO
DURING THE AFTERNOON. RESIDUAL MOISTURE COMBINED WITH THIS TRAILING
ENERGY FIRE OFF ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ACROSS
THE MOUNTAINS DURING THE LATE MORNING WITH COVERAGE INCREASING
DURING THE AFTERNOON AS THEY SPREAD INTO THE ADJACENT VALLEYS AND
PORTIONS OF THE I-25 CORRIDOR. STEERING CURRENTS WILL BE MORE
NORTHERLY TODAY...WHICH SHOULD KEEP MAJORITY SHOWERS/TSTORMS OVER
THE MOUNTAINS. THE EXCEPTION TO THIS WILL BE ACROSS THE PALMER
DIVIDE WHERE SHORT RANGE MODELS INITIATE THUNDERSTORMS ACROSS THE
ELEVATED TERRAIN AND ALONG A WEAK WIND SHIFT BOUNDARY DURING THE
AFTERNOON. MODEL SOUNDINGS SHOW ONLY 100-200 J/KG OF CAPE ACROSS THE
MOUNTAINS AND LCLS LOOK HIGHER THAN PAST COUPLE DAYS...AROUND
625-650 MB. SO ALTHOUGH THE WALDO CANYON BURN SCAR WILL NEED TO BE
MONITORED CLOSELY FOR ANY STRONGER SHOWERS AND THUNDERSTORMS THAT
MIGHT DEVELOP...ESPECIALLY DUE TO THE SATURATED GROUND...THE CHANCES
THAT RAINFALL RATES WILL BE HIGH ENOUGH TO CAUSE A SIGNIFICANT
THREAT OF FLASH FLOODING LOOK LOW AT THIS POINT. THEREFORE WILL NOT
ISSUE ANY FLASH FLOOD WATCHES. HOWEVER THIS DOESN`T MEAN THE
POSSIBILITY DOESN`T EXIST AND THIS WILL NEED TO BE
MONITORED...ESPECIALLY IF DEW POINTS DON`T DROP OFF AS FAST AS
MODELS INDICATE.
CONVECTION DIES OFF QUICKLY DURING THE EVENING WITH ANOTHER
NORTHERLY SURGE DROPPING THROUGH THE SOUTHEAST PLAINS TOWARDS DAWN.
THIS MAY HELP HOLD TEMPERATURES UP A COUPLE DEGREES...KEEPING LOWS
IN THE LOWER 40S. OTHERWISE EXPECT CLEARING SKIES TOWARDS MORNING.
-KT
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI MAY 10 2013
NOT MUCH CHANGE TO THE FORECAST THINKING FOR THE EXTENDED. HIGH
PRESSURE WILL BUILD ACROSS THE GREAT BASIN ON SATURDAY WHILE A
STRONG LOW SPINS OVER EASTERN CANADA. THIS WILL PUT SOUTHERN
COLORADO UNDER NORTHWESTERLY FLOW ALOFT. MODELS INDICATING A WEAK
DISTURBANCE MOVING THROUGH THE FLOW. THIS DISTURBANCE COMBINED
WITH RESIDUAL MOISTURE FROM RECENT RAINFALL WILL LIKELY PRODUCE AT
LEAST SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS AND
PALMER DIVIDE. LIGHTNING AND GUSTY OUTFLOW WINDS WILL LIKELY BE
THE PRIMARY THREATS. GIVEN THE CONVECTIVE NATURE...ANY SHOWERS OR
THUNDERSTORMS THAT DEVELOP OVER THE WALDO CANYON BURN SCAR COULD
PRODUCE LOCALLY HEAVY RAINFALL AND POSSIBLE FLASH FLOODING.
AFTERNOON HIGHS WILL REMAIN IN THE UPPER 60S TO LOWER 70S ACROSS
THE PLAINS. EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DISSIPATE
THROUGH 3AM.
THE HIGH PRESSURE OVER THE GREAT BASIN WILL SHIFT EAST ACROSS
COLORADO SUNDAY AND MONDAY. THIS WILL BRING DRIER AIR INTO THE
ROCKIES AND WEAK STEERING FLOWS ALOFT. MODELS GENERATING MORE
ISOLATED SHOWER AND THUNDERSTORM ACTIVITY EACH AFTERNOON AND
EVENING SUNDAY AND MONDAY. GIVEN THE WEAK STEERING FLOWS NOT
ANTICIPATING MUCH STORM MOVEMENT. TEMPERATURES ALOFT WARM AND
HEIGHTS RISE WHICH WILL HELP AFTERNOON HIGHS WARM INTO THE UPPER
70S TO MID 80S ACROSS THE PLAINS.
THE UPPER RIDGE IS FORECAST TO SHIFT EAST INTO THE CENTRAL PLAINS
ON TUESDAY WHILE A STRONG SHORTWAVE TROUGH MOVES OUT OF THE
PACIFIC NORTHWEST INTO THE NORTHERN PLAINS THROUGH THE MIDDLE OF
THE WEEK. THIS WILL SEND A COLD FRONT INTO THE AREA TUESDAY EVENING.
MODELS WANTING TO DEVELOP THUNDERSTORM ACTIVITY ACROSS THE PLAINS
LATE TUESDAY AFTERNOON INTO THE EVENING HOURS...BUT LACK OF
MOISTURE MAY INHIBIT DEVELOPMENT. FOR NOW DO NOT HAVE
THUNDERSTORMS IN THE FORECAST FOR THE PLAINS...BUT THIS WILL NEED
TO BE MONITORED. AFTERNOON HIGHS ON TUESDAY AHEAD OF THE COLD
FRONT WILL REACH INTO THE MID 80S ON THE PLAINS. HIGHS BEHIND THE
COLD FRONT WEDNESDAY THROUGH FRIDAY WILL REMAIN IN THE MID 70S TO
LOWER 80S. SHOWER AND THUNDERSTORM ACTIVITY WILL REMAIN POSSIBLE
OVER THE MOUNTAIN AREAS THROUGH THE END OF THE WEEK. MOZLEY
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1108 AM MDT FRI MAY 10 2013
MAIN CONCERN TODAY IS CHANCES FOR SHWRS/TS THIS AFTERNOON. A WEAK
DISTURBANCE MOVING FROM N TO S THIS AFTERNOON WILL SPARK SOME SCT
SHOWERS AND ISOLD TS...MAINLY FROM 21Z THROUGH 02Z THIS EVE.
PROB OF PRECIP AT THE TERMINALS IS FAIRLY LOW...20-30 PERCENT...BUT
WILL INCLUDE VCSH IN THE TAFS. THE PROB APPEARS HIGHEST AT KCOS.
PRECIP SHOULD END QUICKLY AFTER SUNSET THIS EVE. OTHERWISE...
EXPECT VFR CONDITIONS AND GENERALLY LIGHT WINDS. ROSE
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...KT
LONG TERM...MOZLEY
AVIATION...ROSE
AREA FORECAST DISCUSSION
NWS PUEBLO CO
851 AM MDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 848 AM MDT FRI MAY 10 2013
UPDATED FORECAST GRIDS AND ZONES TO REFLECT CURRENT CONDITIONS...WITH
GENERALLY CLEAR SKIES ACROSS THE CWA...AND A BAND OF MID LEVEL CLOUDS
MOVING SWD ACROSS THE PALMER DVD AND INTO N EL PASO. ALSO REDUCED
POPS AND TAPERED PRECIP CHANCES TOWARDS LATER THIS AFTERNOON. HRRR IDEA
OF BRINGING SCT SHOWERS ACROSS THE PLAINS BY MID TO LATE AFTERNOON LOOKS
REASONABLE...ALONG WITH BETTER COVERAGE ACROSS THE MTS. ROSE
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 343 AM MDT FRI MAY 10 2013
THE UPPER TROF AXIS WILL CONTINUE TO SHIFT SOUTH OF THE AREA TODAY
WITH SOME TRAILING ENERGY ACROSS SRN WY/NRN CO SINKING ACROSS SE CO
DURING THE AFTERNOON. RESIDUAL MOISTURE COMBINED WITH THIS TRAILING
ENERGY FIRE OFF ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS ACROSS
THE MOUNTAINS DURING THE LATE MORNING WITH COVERAGE INCREASING
DURING THE AFTERNOON AS THEY SPREAD INTO THE ADJACENT VALLEYS AND
PORTIONS OF THE I-25 CORRIDOR. STEERING CURRENTS WILL BE MORE
NORTHERLY TODAY...WHICH SHOULD KEEP MAJORITY SHOWERS/TSTORMS OVER
THE MOUNTAINS. THE EXCEPTION TO THIS WILL BE ACROSS THE PALMER
DIVIDE WHERE SHORT RANGE MODELS INITIATE THUNDERSTORMS ACROSS THE
ELEVATED TERRAIN AND ALONG A WEAK WIND SHIFT BOUNDARY DURING THE
AFTERNOON. MODEL SOUNDINGS SHOW ONLY 100-200 J/KG OF CAPE ACROSS THE
MOUNTAINS AND LCLS LOOK HIGHER THAN PAST COUPLE DAYS...AROUND
625-650 MB. SO ALTHOUGH THE WALDO CANYON BURN SCAR WILL NEED TO BE
MONITORED CLOSELY FOR ANY STRONGER SHOWERS AND THUNDERSTORMS THAT
MIGHT DEVELOP...ESPECIALLY DUE TO THE SATURATED GROUND...THE CHANCES
THAT RAINFALL RATES WILL BE HIGH ENOUGH TO CAUSE A SIGNIFICANT
THREAT OF FLASH FLOODING LOOK LOW AT THIS POINT. THEREFORE WILL NOT
ISSUE ANY FLASH FLOOD WATCHES. HOWEVER THIS DOESN`T MEAN THE
POSSIBILITY DOESN`T EXIST AND THIS WILL NEED TO BE
MONITORED...ESPECIALLY IF DEW POINTS DON`T DROP OFF AS FAST AS
MODELS INDICATE.
CONVECTION DIES OFF QUICKLY DURING THE EVENING WITH ANOTHER
NORTHERLY SURGE DROPPING THROUGH THE SOUTHEAST PLAINS TOWARDS DAWN.
THIS MAY HELP HOLD TEMPERATURES UP A COUPLE DEGREES...KEEPING LOWS
IN THE LOWER 40S. OTHERWISE EXPECT CLEARING SKIES TOWARDS MORNING.
-KT
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 343 AM MDT FRI MAY 10 2013
NOT MUCH CHANGE TO THE FORECAST THINKING FOR THE EXTENDED. HIGH
PRESSURE WILL BUILD ACROSS THE GREAT BASIN ON SATURDAY WHILE A
STRONG LOW SPINS OVER EASTERN CANADA. THIS WILL PUT SOUTHERN
COLORADO UNDER NORTHWESTERLY FLOW ALOFT. MODELS INDICATING A WEAK
DISTURBANCE MOVING THROUGH THE FLOW. THIS DISTURBANCE COMBINED
WITH RESIDUAL MOISTURE FROM RECENT RAINFALL WILL LIKELY PRODUCE AT
LEAST SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE MOUNTAINS AND
PALMER DIVIDE. LIGHTNING AND GUSTY OUTFLOW WINDS WILL LIKELY BE
THE PRIMARY THREATS. GIVEN THE CONVECTIVE NATURE...ANY SHOWERS OR
THUNDERSTORMS THAT DEVELOP OVER THE WALDO CANYON BURN SCAR COULD
PRODUCE LOCALLY HEAVY RAINFALL AND POSSIBLE FLASH FLOODING.
AFTERNOON HIGHS WILL REMAIN IN THE UPPER 60S TO LOWER 70S ACROSS
THE PLAINS. EXPECT SHOWER AND THUNDERSTORM ACTIVITY TO DISSIPATE
THROUGH 3AM.
THE HIGH PRESSURE OVER THE GREAT BASIN WILL SHIFT EAST ACROSS
COLORADO SUNDAY AND MONDAY. THIS WILL BRING DRIER AIR INTO THE
ROCKIES AND WEAK STEERING FLOWS ALOFT. MODELS GENERATING MORE
ISOLATED SHOWER AND THUNDERSTORM ACTIVITY EACH AFTERNOON AND
EVENING SUNDAY AND MONDAY. GIVEN THE WEAK STEERING FLOWS NOT
ANTICIPATING MUCH STORM MOVEMENT. TEMPERATURES ALOFT WARM AND
HEIGHTS RISE WHICH WILL HELP AFTERNOON HIGHS WARM INTO THE UPPER
70S TO MID 80S ACROSS THE PLAINS.
THE UPPER RIDGE IS FORECAST TO SHIFT EAST INTO THE CENTRAL PLAINS
ON TUESDAY WHILE A STRONG SHORTWAVE TROUGH MOVES OUT OF THE
PACIFIC NORTHWEST INTO THE NORTHERN PLAINS THROUGH THE MIDDLE OF
THE WEEK. THIS WILL SEND A COLD FRONT INTO THE AREA TUESDAY EVENING.
MODELS WANTING TO DEVELOP THUNDERSTORM ACTIVITY ACROSS THE PLAINS
LATE TUESDAY AFTERNOON INTO THE EVENING HOURS...BUT LACK OF
MOISTURE MAY INHIBIT DEVELOPMENT. FOR NOW DO NOT HAVE
THUNDERSTORMS IN THE FORECAST FOR THE PLAINS...BUT THIS WILL NEED
TO BE MONITORED. AFTERNOON HIGHS ON TUESDAY AHEAD OF THE COLD
FRONT WILL REACH INTO THE MID 80S ON THE PLAINS. HIGHS BEHIND THE
COLD FRONT WEDNESDAY THROUGH FRIDAY WILL REMAIN IN THE MID 70S TO
LOWER 80S. SHOWER AND THUNDERSTORM ACTIVITY WILL REMAIN POSSIBLE
OVER THE MOUNTAIN AREAS THROUGH THE END OF THE WEEK. MOZLEY
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 343 AM MDT FRI MAY 10 2013
VFR CONDITIONS EXPECTED AT THE TAF SITES THROUGH MOST OF THE DAY.
KPUB COULD SEE SOME PATCHY FOG THIS MORNING WITH VIS DROPPING INTO
THE MVFR CATEGORY. ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP
OVER THE MOUNTAINS DURING THE AFTERNOON...PRODUCING MVFR TO LOCAL
IFR CIGS WITH THE STRONGER SHOWERS/TSTORMS. KCOS WILL SEE THE BEST
CHANCE FOR VCSH/VCTS DURING THE AFTERNOON WITH VFR TO POSSIBLY BRIEF
MVFR CIGS...WHILE KPUB AND KALS ARE MORE LIKELY TO REMAIN DRY.
CONVECTION SHOULD DIMINISH QUICKLY THIS EVENING WITH LIGHT WINDS AND
CLEARING SKIES. ANOTHER NORTHERLY SURGE DROPS THROUGH THE PLAINS
AFTER 06Z WHICH COULD BRING SOME ENHANCED NORTHERLY WINDS 10-15 KTS
AT KCOS TOWARDS 12Z. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ROSE
SHORT TERM...KT
LONG TERM...MOZLEY
AVIATION...KT
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1113 PM MDT THU MAY 9 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY NIGHT)
ISSUED AT 247 PM MDT THU MAY 9 2013
ELONGATED UPPER LOW FROM SRN CA ACROSS THE 4 CORNERS TO ERN CO WAS
GETTING STRETCHED APART THIS AFTERNOON...AS THE EASTERN PORTION
MOVES INTO THE PLAINS WHILE THE WESTERN PORTION DROPS SOUTHWARD.
CONVECTION WAS A LITTLE SLOW GETTING GOING TODAY...BUT RECENT KGJX
RADAR SHOWED ECHOES BUILDING ALONG THE TAVAPUTS/ROAN PLATEAUS TO THE
FLATTOPS...AND OVER THE CENTRAL AND SOUTHERN MTNS. INSTABILITY
LIKELY THE DRIVING FORCE THOUGH RAP MODEL INDICATED SOME 700-500 MB
LAYER CONVERGENCE SOUTH OF I-70 AND UNDER THE DEFORMATION/UPPER LOW
AXIS ALOFT. ISOLATED THUNDERSTORMS WILL BE POSSIBLE WITH GUSTY WINDS
AND PERHAPS SOME GRAUPEL. WILL KEEP THE CURRENT WINTER HIGHLIGHTS
GOING THOUGH PRECIPITATION LIKELY TO BE QUITE VARIABLE GIVEN THE
CONVECTIVE NATURE OF THE SHOWERS.
THE DEFORMATION ZONE SINKS SOUTH OF OUR AREA THIS EVENING AND
TONIGHT. WITH ITS EXIT AND THE LOSS OF DAYTIME HEATING...EXPECT
SHOWERS TO DIMINISH BY LATE EVENING.
A SHORTWAVE DISTURBANCE DROPPING DOWN ACROSS WRN MT THIS AFTERNOON
WILL REACH OUR FORECAST AREA BY FRI MORNING. NE UT/NW CO SHOULD SEE
CLOUDS BACK ON THE INCREASE BY SUNRISE. WEAK MOISTURE TRANSPORT IN
THE NORTHERN FLOW ALONG THIS PASSING WEAK DISTURBANCE AND DAYTIME
INSTABILITY SHOULD TRIGGER A ROUND OF AFTERNOON SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS FRIDAY AFTERNOON...MAINLY OVER THE HIGHER
TERRAIN. SNOW WILL GENERALLY BE CONFINED TO ABOVE 9500-10K FT. HIGH
TEMPS FRIDAY WILL BE WARMER THAN TODAY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 247 PM MDT THU MAY 9 2013
A HIGHLY AMPLIFIED PATTERN THROUGH THE WEEKEND FLATTENS EARLY NEXT
WEEK. THERE IS HIGH FORECAST CONFIDENCE THROUGH MONDAY...THEN MODELS
SHOW INCREASING SPREAD IN FORECAST DETAILS.
A POSITIVELY TILTED RIDGE AXIS AMPLIFIES FROM THE EASTERN PACIFIC
INTO THE NORTHERN ROCKIES. THEN SLOWLY PROGRESSES UNTIL IT IS
OVERHEAD ON MONDAY. A PORTION OF THE LOW PRESSURE SYSTEM THAT
BROUGHT SHOWERS ON WEDNESDAY INTO THURSDAY IS CUTOFF IN SONORA
MEXICO. NEAR NORMAL TEMPERATURES ON SATURDAY WILL RISE WELL ABOVE
NORMAL BY MONDAY. THE WARMING AFTERNOON TEMPERATURES AND MARGINAL
MOISTURE LOOK TO OVERCOME SUBSIDENCE ON SATURDAY FOR SCATTERED
MAINLY MOUNTAIN THUNDERSTORMS. INCREASING SUBSIDENCE ON SUNDAY AND
MONDAY WITH MOISTURE DIMINISHING DUE TO CONVECTIVE VENTILATION
DIMINISH THE CHANCES OF MOUNTAIN SHOWERS. MONDAY AFTERNOON
TEMPERATURES WILL RISE ABOUT 10 DEGREES ABOVE NORMAL.
ON MONDAY A TROUGH WORKS INTO BC-WASHINGTON AND LIFTS THROUGH THE
NORTHERN ROCKIES ON TUESDAY. THIS BREAKS DOWN THE LOCAL RIDGE AND
ALSO ENTRAINS THE SONORA LOW...BOTH OF WHICH MAY INCREASE DIURNAL
THUNDERSTORM COVERAGE FOR TUESDAY INTO WEDNESDAY. BY THURSDAY BOTH
THE EC AND GFS ARE DIGGING A SHALLOW TROUGH ALONG THE WEST COAST
THAT MAY THREATEN INCREASED SHOWERS TOWARDS THE NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1113 PM MDT THU MAY 9 2013
EXPECT VFR CONDITIONS ACROSS THE REGION THROUGH 18Z FRIDAY.
RESIDUAL MOISTURE AND DAY TIME HEATING WILL YIELD SCATTERED
SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS. AS A RESULT...LOOK
FOR AREAS OF MOUNTAIN OBSCURATION AND GUSTY OUTFLOW WINDS IN THE
HIGH COUNTRY. THUNDERSTORMS WILL LARGELY REMAIN ANCHORED TO THE
HIGHER TERRAIN...THOUGH THERE IS A CHANCE THAT KEGE...KASE...KGUC
...KDRO AND KPSO MAY EXPERIENCE BRIEF SHOWERS OR THUNDERSTORMS
FROM 22Z FRI TO 03Z SAT AS DIURNAL CIRCULATIONS BREAK DOWN. THERE
IS A LOW END CHANCE THAT MVFR CONDITIONS WILL RESULT FROM THIS
ACTIVITY. ELSEWHERE...VFR CONDITIONS WILL CONTINUE.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JAD
LONG TERM...JOE
AVIATION...NL
AREA FORECAST DISCUSSION
NWS TAUNTON MA
754 PM EDT SAT MAY 11 2013
.SYNOPSIS...
SHOWERS AND OCCASIONAL THUNDERSTORMS CONTINUE THIS EVENING AND
OVERNIGHT AS A COLD FRONT SLOWLY CROSSES THE REGION. THE FRONT
WILL THEN STALL SUNDAY BEFORE MOVING TO THE EAST SUNDAY NIGHT.
COOLER AND DRIER WEATHER WILL FOLLOW FOR EARLY NEXT WEEK. EXPECT A
RETURN TO A MORE UNSETTLED PATTERN FOR THE LATTER PART OF NEXT
WEEK AS A FRONT STALLS OVER OR JUST SOUTH OF THE AREA.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
* SOME THUNDER THIS EVENING AND OVERNIGHT.
* PRIMARY THREATS...GUSTY WINDS AND OCCASIONAL URBAN/POOR DRAINAGE
FLOODING
730 PM UPDATE...
STRONG UPPER JET DYNAMICS FOR THIS TIME OF YEAR AND CONDITIONAL
INSTABILITY SHOULD ALLOW FOR ELEVATED CONVECTION REST OF THIS
EVENING AS SFC FRONT SLOWS AND STALLS IN THE AREA. HRR SEEMS TO BE
HANDLING HIGHER REFLECTIVITY CLUSTERS WELL SO FAR THIS EVENING.
SVR THREAT LOOKS TO BE LOW IN OUR AREA TONIGHT AND LOOKS LIKE
SUFFICIENT CELL MOVEMENT TO KEEP FLASH FLOOD RISK RELATIVELY LOW.
NONETHELESS...SOME OF THE SHOWERS/TSTMS WILL CONTAIN HEAVY
DOWNPOURS AND WILL NEED TO MONITOR IN EVENT OF ANY TRAINING AS
FRONT SLOWS DOWN LATER THIS EVENING. THERE IS LIKELY TO BE URBAN
STREET FLOODING...ESPECIALLY RI AND SE MA. CANNOT RULE OUT AN
URBAN FLASH FLOOD EVENT.
4 PM DISCUSSION...
INITIAL CONVECTIVE BAND CONTINUES TO WEAKEN ALONG THE S COASTAL
WATERS AND WILL CLIP SE MA AND SRN RI THROUGH THE EARLY EVENING.
MOST OF THE THUNDER ASSOCIATED WITH THIS BAND SHOULD REMAIN WELL S
OF LAND PRIMARILY DUE TO MOSTLY CLEAR SKIES WHICH HAVE STAYED
FURTHER S ALL DAY. CONDITIONS ARE GENERALLY MORE STABLE TO THE N.
HOWEVER...WILL NEED TO CONTINUE TO MONITOR DEVELOPING CONVECTION
MORE CLOSELY ASSOCIATED WITH A COLD FRONTAL BOUNDARY CURRENTLY
LOCATED THROUGH CENTRAL NY AND INTO PA. COMBINATION OF SLIGHTLY
HIGHER DWPTS AND SOME CLEARING OF THE MID AND HIGH LVL CLOUDS HAS
ALLOWED CONVECTION TO FIRE AND BECOME A BIT MORE ORGANIZED IN SRN
NY AND NJ. WILL NEED TO MONITOR THIS AS THE FRONT MAKES ITS E
PROGRESSION. MESOSCALE MODELS CONTINUE TO INDICATE SOME
DESTABILIZATION OVER SRN NEW ENGLAND...BUT NOT NEARLY AS MUCH AS
WHERE CLEARING HAS OCCURRED. THEREFORE...WILL HAVE TO WATCH THE
CLEARING THROUGH THE EVENING WHILE THE SUN IS STILL UP. SB CAPE
VALUES HAVE SHOT UP TO ABOUT 1000 J/KG IN THE AREAS WHERE CLEARING
HAS OCCURRED. SHEAR STILL DECENT...WITH 30-40 KT 0-6KM OUT OF THE
W...HOWEVER IT WOULD NEED THE BETTER DESTABILIZATION FOR ANY
STORMS TO BECOME ORGANIZED.
OVERNIGHT HOWEVER...THE TREND WILL BE TOWARD SOME UPPER LVL
INSTABILITY AS NOSE OF 40 KT LLJ MOVES OVER ESPECIALLY S AND SE
AREAS. STILL NOTING 1.0+ INCH PWAT AIRMASS AND DECENT THETA-E
RIDGING TO WORK WITH PARTICULARLY RI AND E MASS AFTER THE BAND OF
INTERIOR CONVECTION WEAKENS WITH TIME OVER THE AREA.
THEREFORE...THE TRANSITION...AND PRIMARY THREAT WILL BE TOWARD THE
POTENTIAL FOR ISOLATED HEAVY DOWNPOURS WITH A FOCUS ON THE E AS
THE FRONT BEGINS TO CROSS THE AREA AND STALL. THUNDER STILL NOT
OUR OF THE QUESTION...BUT ITS LIKELY TO BE MORE ISOLATED IN NATURE
THAN THIS AFTERNOON AND EARLY EVENING. TYPICAL POOR DRAINAGE
FLOODING IS POSSIBLE IN SOME SPOTS...PARTICULARLY WITH ANY
CONVECTIVE ELEMENTS THAT FORM THIS EVENING OR OVERNIGHT. HRRR POPS
HAVE BEEN QUITE GOOD TODAY...SO ADJUSTED THE EVENING AND OVERNIGHT
POPS TOWARD ITS SOLUTION.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
SUNDAY...
SFC COLD FRONT PROGGED TO STALL IN ERN MA DURING THE EARLY MORNING
HOURS UNTIL SECONDARY KICKER WAVE ROTATES W TO E AROUND THE CUTOFF
LOW PRES IN QUEBEC. AT THE SAME TIME...MODELS CONTINUE TO INDICATE
A SECONDARY SURGE OF HIGHER THETA-E ARE AND A SECONDARY LLJ TO
MOVE UP AND E OF THE THIS FRONT DURING THE MORNING HOURS. GIVEN
THIS...EVEN AS BULK OF PRECIP SLOWLY SHIFTS OFFSHORE OF ERN MA AND
THE CAPE/ISLANDS...MAY SEE ANOTHER HEAVIER BAND OF PRECIPITATION
FORM DURING THE DAYLIGHT HOURS AND CROSS FROM S TO N PARTICULARLY
OVER E AND SE PORTIONS OF THE FORECAST AREA. ALSO...WITH SOME
BREAKS POSSIBLE...AND THE CONVERGENCE PROVIDED BY THE FRONT...MAY
SEE -SHRA AND EVEN AN ISOLATED RUMBLE OF THUNDER AS FAR WEST AS A
IJD-ORH-MHT LINE. HOWEVER...WITH THE COMBINATION OF THIS KICKER
WAVE ALLOWING THE FRONT TO PROGRESS...AND A DRIER MORE STABLE
AIRMASS FILTERING IN BEHIND THE FRONT...NOT EXPECTING RAINFALL TO
BE AS WIDESPREAD OR AS POTENTIALLY HEAVY EVERYWHERE AS IT WAS ON
SATURDAY. MOST LOCATIONS W OF THE LINE ABOVE REMAIN DRY AND
PROGRESSIVELY GIVE WAY TO SUNNY SKIES. THIS TOO WILL BE THE TREND
FOR THE EAST BY LATE AFTERNOON AND EVENING MODELS INDICATE. WILL
NEED TO WATCH SE MASS...CAPE/ISLANDS ESPECIALLY FOR ANY HEAVY
RAINFALL. MAY NEED TO MONITOR THE CAPE/ISLANDS FOR A SECONDARY
DENSE FOG THREAT SHOULD THE PRECIP MOVE A LITTLE BIT FURTHER
OFFSHORE...BUT WITH RAIN MIXING IN THE BL...IT APPEARS TO BE A
SLIGHTLY LOWER THREAT THAN PREVIOUS NIGHTS.
SUN NIGHT...
CLEARING TREND EXPECTED DURING THE OVERNIGHT HOURS. HOWEVER...SFC
PRES GRADIENT IS EXPECTED TO REMAIN AT LEAST SOMEWHAT TIGHT...SO
NOT EXPECTING FULL DECOUPLING. EVEN STILL TEMPERATURES ARE
EXPECTED TO DIP TO NEAR FREEZING IN NW MA AND PORTIONS OF SW NH
WITH MID TO UPPER 30S TOWARD THE S AND E. WINDS AROUND 10 MPH
WOULD PRECLUDE FROST POTENTIAL...BUT THIS WILL NEED TO BE
MONITORED GIVEN NEWLY ACTIVATED GROWING SEASON IN SOME SPOTS AND
TEMPERATURES DIPPING CLOSE TO THE FREEZING MARK.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
HIGHLIGHTS...
* COOL AND DRY MONDAY AND TUESDAY
* UNSETTLED WEATHER THE LATTER HALF OF THE WEEK
THERE IS REASONABLY GOOD AGREEMENT ON THE LARGE SCALE PATTERN BY
THE MEDIUM RANGE MODELS THROUGH THE COMING WEEK. RELATIVELY HIGH
AMPLITUDE TROF BRINGS UNSEASONABLY CHILLY AIR MASS TO THE REGION
MON THRU TUE NIGHT. RIDGE ACROSS THE S CENTRAL US BUILDS EAST ON
WED BUT STRONG TROF ACROSS CANADA SHOULD KEEP RELATIVELY FAST WEST
TO EAST FLOW ACROSS SOUTHERN NEW ENGLAND WITH A HIGH LIKELIHOOD OF
A FRONT STALLING OVER OR JUST SOUTH OF THE FORECAST AREA. BY THE
WEEKEND...LOOKS LIKE A DRY NW FLOW BECOMES ESTABLISHED OVER THE
AREA WITH DRY AND PROBABLY SEASONABLE TEMPERATURES.
MON THRU TUE NIGHT...SHOULD BE DRY AND COOL WITH -1 TO -3C 850MB
TEMP AIR. THE AVERAGE START OF THE GROWING SEASON EXPANDED INTO A
LARGE PART...BUT NOT ALL...OF INTERIOR SOUTHERN NEW ENGLAND ON MAY
10. THERE MAY BE A NEED FOR FROST ADVISORIES OR FREEZE WARNINGS
FOR A PORTION OF THE AREA MON NIGHT UNDER CLEAR SKIES AND PROBABLY
DECOUPLING WINDS OVER THE INTERIOR TO ASSIST WITH RADIATIONAL
COOLING...ALBEIT FOR A RELATIVELY SHORT NIGHT AT THIS TIME OF
YEAR.
WED INTO WED NIGHT...SPELL A CHANGE IN THE WEATHER PATTERN.
ALTHOUGH THERE ARE SOME TIMING DIFFERENCES...MEDIUM RANGE MODELS
SUGGEST WARM ADVECTION BECOMING ESTABLISHED ON WED...AND BY WED
EVENING THE WARM ADVECTION MAY TRIGGER ENOUGH OF AN INSTABILITY
BURST AS SEEN IN K INDEX PROJECTIONS FOR AT LEAST SCT SHOWERS AND
TSTMS.
THU THRU FRI...WILL PROBABLY BE UNSETTLED AS FRONTAL BOUNDARY
STALLS OVER OR A LITTLE SOUTH OF SOUTHERN NEW ENGLAND AND REGION
IS VULNERABLE SHORT WAVE ENERGY PASSING BETWEEN A SOUTHERN UPPER
RIDGE AND E CENTRAL CANADA TROF. IT IS TOO FAR OUT IN TIME TO HAVE
MUCH CONFIDENCE IN DETAILS BUT FOR NOW INDICATED CONSIDERABLE
CLOUDINESS AND CHANCE SHOWERS/TSTMS.
SAT...BOTH 12Z ECMWF AND GFS SUGGEST A DRIER NW FLOW BECOMING
ESTABLISHED ALTHOUGH CONFIDENCE THAT FAR OUT IS NOT TOO HIGH. BY
THE WEEKEND...DIFFERENCES IN THE SYNOPTIC FLOW BECOME MORE
APPARENT WITH THE ECMWF DEPICTING A STRONGER NORTHERN STREAM AND
THE GFS SHOWING A WEAKER NORTHERN STREAM.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...LOW CONFIDENCE...PARTICULARLY ON TIMING OF IFR
CONDITIONS TONIGHT INTO EARLY SUN MORNING. CONFIDENCE GROWS TO GENERALLY
HIGH SUNDAY AND SUNDAY NIGHT. CONDITIONS HAVE BEEN UP AND DOWN
WITH SHOWER ACTIVITY THRU EARLY THIS EVENING BUT THINK OVERALL
TREND WILL BE TO LOWER CONDITIONS LATER THIS EVENING. ANTICIPATE
MOSTLY MVFR CONDITIONS WITH CIGS AND VSBYS IN BANDS OF SHOWERS AND
AREAS OF FOG WITH LOCALIZED IFR CIGS/VSBYS BECOMING MORE PREVALENT
DURING THE NIGHT. ISOLD EMBEDDED TSTMS TONIGHT...ESPECIALLY S/SE
OF BOS-BDL LINE.
THROUGH MID MORNING SUN...
AS A SLOW MOVING COLD FRONT CROSSES THE AREA...EXPECTING A COMPLEX
MIX OF VFR/MVFR/IFR THIS AFTERNOON IN OCCASIONAL -SHRA AND LOW
CIGS. A THUNDERSTORM OR TWO CAN/T BE RULED OUT LATE THIS AFTERNOON
OR EVENING AS WELL. OTHERWISE...THE TREND WILL BE TOWARD ALL IFR
AS FOG AND LOW CIGS DEVELOP THIS EVENING AND LINGER MUCH OF THE
NIGHT. SHOWERS CONTINUE ACROSS THE REGION DURING THIS TIME AS
WELL. EXPECT IMPROVEMENT FROM W TO E DURING THE EARLY TO MID
MORNING HOURS...BUT WILL LIKELY SEE MOSTLY IFR IN THE EAST.
EARLY AFTERNOON SUN THROUGH SUN NIGHT...
IMPROVING CONDITIONS WITH LIKELY VFR EVERYWHERE BY AFTERNOON SUN.
THE VFR CONDITIONS CONTINUE INTO SUN NIGHT. WINDS MAY GUST TO 20
KT DURING THE DAY SUN OUT OF THE W.
KBOS TERMINAL...OVERALL MODERATE CONFIDENCE ON CIG FORECAST. WE
EXPECT MVFR CIGS THIS EVENING TO DROP TO IFR FOR A TIME OVERNIGHT.
LOW CONFIDENCE ON VSBYS WHICH WILL VARY THIS EVE WITH SHOWERS
MOVING THRU. ANTICIPATE GENERALLY 2 TO 4 MI IN BR AND OCCASIONAL
SHRA. CIGS AND VSBYS SHOULD IMPROVE TO VFR 14-16Z. HIGH CONFIDENCE
OF VFR SUN AFTERNOON AND NIGHT.
KBDL TERMINAL...MODERATE CONFIDENCE IN TAF.
OUTLOOK...MONDAY THROUGH THURSDAY...
HIGH CONFIDENCE OF VFR CONDITIONS MON THROUGH MUCH OF WED.
MODERATE CONFIDENCE OF DEVELOPING MVFR CONDITIONS IN SHOWERS AND
PATCHY FOG WED EVE AND OCCASIONAL MVFR CONDITIONS IN SCT
SHOWERS/TSTMS AND PATCHY FOG WED NIGHT THRU THU.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
FORECAST CONFIDENCE HIGH THROUGH SUNDAY NIGHT.
NEAR TERM...ALLOWING SCA FOR NAR BAY AND BOS HARBOR EXPIRE AT 8 PM
AS WINDS HAVE DIMINISHED.
OVERNIGHT...WINDS OF 25-30 KT GRADUALLY SUBSIDE THIS
EVENING...EXCEPT FOR THE POTENTIAL FOR HIGHER GUSTS IN ANY
THUNDERSTORMS WHICH MAY CROSS THE WATERS /PARTICULARLY SRN
WATERS/ OVERNIGHT. HOWEVER...SEAS WITH BUILDING SWELL ARE LIKELY
TO STAY ELEVATED 5-7 FT OVER SRN WATERS AND E OUTER WATERS. SMALL
CRAFT ADVISORIES CONTINUE.
SUNDAY...
SMALL CRAFT ADVISORIES CONTINUE FOR SEAS ON THE OUTER WATERS SRN
WATERS IMMEDIATELY S OF RHODE ISLAND. HOWEVER...MAY SEE A SECOND
SURGE OF WIND GUSTS...PARTICULARLY NEAR SHORE...TO 25 KT. SO MAY
NEED TO RE-ISSUE SMALL CRAFT ADVISORY FOR THE DAYLIGHT HOURS ON
SOME NEAR SHORE ZONES.
SUN NIGHT...
ASIDE FROM CONTINUING SWELL ON OUTER WATERS /WHERE SCA CONTINUES/
SEAS AND WINDS SUBSIDE.
OUTLOOK...MONDAY THROUGH THURSDAY...
ENOUGH NW TO N GRADIENT MAY RESULT IN SCA GUSTS OVER THE COASTAL
WATERS MON INTO MON EVE. LIGHT WINDS AND SUBSIDING SEAS EXPECTED
TUE. ALTHOUGH WINDS WILL BE INCREASING ALOFT...SURFACE WINDS ARE
PRESENTLY EXPECTED TO REMAIN LIGHT WED INTO THU...EXCEPT IN
VICINITY OF ANY ISOLD TSTMS WED NIGHT AND THU.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR
ANZ230>234-236-251.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT SUNDAY FOR ANZ235-237-250.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT MONDAY FOR ANZ254>256.
&&
$$
SYNOPSIS...DOODY/THOMPSON
NEAR TERM...DOODY/THOMPSON
SHORT TERM...DOODY
LONG TERM...THOMPSON
AVIATION...DOODY/THOMPSON
MARINE...DOODY/THOMPSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
728 PM EDT SAT MAY 11 2013
.AVIATION...
ONGOING CONVECTION JUST INLAND OF THE BROWARD AND MIAMI-DADE
TERMINALS WILL CONTINUE TO DRIFT EASTWARD TOWARD THE TERMINALS
THROUGH THE MID-EVENING HOURS. HAVE INCLUDED TEMPO GROUPS TO
SUPPORT THIS AND WILL UPDATE IF NEEDED. THIS ACTIVITY SHOULD TREND
DOWN THROUGH THE MID TO LATE EVENING HOURS. ELSEWHERE...ANOTHER
QUIET NIGHT IS ANTICIPATED WITH WINDS BECOMING LIGHT. SIMILAR
CONDITIONS EXPECTED ONCE AGAIN ON SUNDAY WITH AFTERNOON CONVECTION
FAVORING THE EAST COAST WITH THE SW FLOW IN PLACE UP TO 10 KFT.
&&
.PREV DISCUSSION... /ISSUED 210 PM EDT SAT MAY 11 2013/
..CORRECTED LONG RANGE TIME FRAME...
SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
SOUTH FLORIDA IS CURRENTLY UNDER NEAR ZONAL FLOW WITH A MID LEVEL
RIDGE TO THE EAST AND A LARGE CUT-OFF LOW OVER NORTHERN MEXICO. A
FAST MOVING WAVE IS EMBEDDED IN THE ZONAL FLOW PATTERN CURRENTLY
MOVING INTO THE FLORIDA PANHANDLE WITH A LARGE CLUSTER OF CONVECTION
ASSOCIATED WITH IT. THE PROXIMITY OF THIS WAVE ALONG WITH PLENTY OF
SUNSHINE EARLY TODAY AND INSTABILITY WILL CAUSE ANOTHER ROUND OF
LATE AFTERNOON AND EARLY EVENING THUNDERSTORMS DEVELOPING OVER THE
INTERIOR AND THEN WILL DRIFT BACK TOWARDS THE EAST COAST. AT THE
SURFACE, A RIDGE IS LOCATED ACROSS SOUTH FLORIDA PRODUCING A LOW
LEVEL SOUTHERLY FLOW WHICH WILL TEND TO KEEP THE INITIATION OF
CONVECTION WELL INLAND FROM THE COASTS OF MIAMI-DADE AND COLLIER
COUNTIES.
LOOKING UPSTREAM, A MAJOR MID LEVEL TROUGH WILL DEEPEN ACROSS
EASTERN NORTH AMERICA THROUGH MONDAY WITH ITS ASSOCIATED WEAKENING
COLD FRONT MOVING INTO NORTH FLORIDA ON SUNDAY AND INTO SOUTH
FLORIDA BY LATE MONDAY. THIS WILL PROVIDE A CONTINUED THREAT FOR
MAINLY AFTERNOON AND EVENING CONVECTION FAVORING THE INTERIOR AND
EAST COAST. FORECAST SOUNDINGS SHOW SLOW STORM MOTION AGAIN ON
SUNDAY BUT A STRONGER WESTERLY STEERING FLOW ON MONDAY AS THE TROUGH
DEEPENS FURTHER. THE PWAT IS ALSO FORECAST TO REMAIN IN THE RANGE OF
1.5-1.7 INCHES WHICH IS ABOVE THE AVERAGE FOR MID MAY. IN ADDITION,
500 MB TEMPERATURES ARE FORECAST TO HOVER AROUND -10 TO -11 CELSIUS
THROUGH MONDAY AND THIS IS ONE TO TWO DEGREES BELOW THE AVERAGE SO
ALSO ADDING FUEL TO THE MIX. THE COLD FRONT WILL PUSH OFF THE
SOUTHEAST COAST MONDAY EVENING AND BRING A REFRESHING FEELING TO
THE AIR WITH TEMPERATURES FALLING TO ABOUT 8-10 DEGREES BELOW
NORMAL MONDAY NIGHT.
LONG TERM (TUESDAY THROUGH SATURDAY)... THE TROUGH WILL BEGIN TO
SHIFT EAST ON TUESDAY WITH A RIDGE BUILDING ACROSS THE GULF OF
MEXICO WHICH WILL FILTER A MUCH DRIER AIR MASS INTO SOUTH FLORIDA
CONTINUING THROUGH MUCH OF THE WEEK. THERE IS HOWEVER ONE
DISCREPANCY IN THE LONG RANGE MODELS BY THE END OF THE FORECAST.
BOTH THE ECMWF AND GFS SHOW THE CUT-OFF LOW CURRENTLY OVER
NORTHERN MEXICO TO BEGIN LIFTING EASTWARD BY THE MIDDLE OF THE
WEEK. HOWEVER, THE 00Z RUN OF THE ECMWF SHOWS THIS LOW SHIFTING
NEARLY DUE EAST AND ACROSS NORTH FLORIDA BY FRIDAY AND SATURDAY
WHICH WOULD TEND TO DESTABILIZE SOUTH FLORIDA ONCE AGAIN WHILE THE
LAST FEW RUNS OF THE GFS HAVE SHOWN THE LOW LIFTING MORE TO THE
NORTHEAST WELL NORTH OF THE PENINSULA. THE 12Z RUN HAS SHIFTED A
TAD FARTHER TO THE SOUTH BUT WILL WAIT FOR MORE CONSISTENT RUNS
BEFORE ADJUSTING THE FORECAST KEEPING IT DRY FOR NOW INTO NEXT
WEEKEND.
AVIATION...
SHRAS/TSRAS ALREADY BEGINNING TO DEVELOP ACROSS INTERIOR SECTIONS OF
PALM BEACH...BROWARD...AND MIAMI-DADE COUNTIES EARLY THIS AFTERNOON.
THIS ACTIVITY WILL CONTINUE THROUGH THE LATE AFTERNOON AND EARLY
EVENING HOURS MUCH LIKE YESTERDAY. LATEST HRRR DEPICTS FURTHER
ACTIVITY DEVELOPING ACROSS THE INTERIOR OVER THE NEXT FEW HOURS AND
PUSHING EAST AS A RESULT OF THE GULF BREEZE THAT IS ALREADY WELL
ESTABLISHED. PLACED VCTS AT ALL EAST COAST TERMINAL SITES EXCEPT FOR
KTMB THROUGH THE EARLY EVENING HOURS. ACTIVITY SHOULD QUICKLY
DIMINISH WITH LOSS OF HEATING. FLOW SHOULD THEN GENERALLY BE
SOUTHERLY AND LIGHT OVERNIGHT.
MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE THROUGH THE WEEKEND OUTSIDE
OF ISOLATED STRONG CONVECTION. A COLD FRONT WILL MOVE ACROSS THE
SOUTH FLORIDA WATERS LATE MONDAY WITH STRONG HIGH PRESSURE
BUILDING BEHIND THE FRONT WITH INCREASING WIND AND SEAS MONDAY
NIGHT INTO MID WEEK.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE THROUGH MONDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 86 73 85 / 40 50 30 30
FORT LAUDERDALE 77 86 74 85 / 60 50 20 50
MIAMI 76 87 75 87 / 60 40 20 50
NAPLES 73 87 73 85 / 10 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MIAMI FL
158 PM EDT FRI MAY 10 2013
.AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE NEXT 24 HOURS.
STILL BELIEVE A FEW SHRAS/TSRAS WILL BE POSSIBLE ACROSS MAINLY THE
INTERIOR AND SHOULD NOT AFFECT ANY TAF SITE. LATEST SHORT TERM
GUIDANCE CONTINUES TO SUGGEST THIS AND ALSO PUSHING SOME OF THE
ACTIVITY EASTWARD...POSSIBLY INTERACTING WITH A WEAK SEA
BREEZE...TOWARD KPBI BY 00Z. KEPT ANY PRECIP MENTION OUT OF KPBI
TAF FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 1007 AM EDT FRI MAY 10 2013/
UPDATE...
LOOKING TO BE A VERY TRICKY FORECAST THIS MORNING. A WEAK MID
LEVEL TROUGH MOVED ACROSS SOUTH FLORIDA DURING THE LATE AFTERNOON
YESTERDAY AND LAST NIGHT SPARKING CONVECTION PARTICULARLY OFFSHORE
THIS MORNING WHICH THEN BUILT BACK ONSHORE. THAT CONVECTION HAS
NOW WANED AS THE TROUGH CONTINUES TO MOVE EAST. THE INTERESTING
PHENOMENA THIS MORNING IS THE 12Z MFL SOUNDING WHICH SHOWS
SIGNIFICANT WARMING AT 500 MB WITH A DISTINCT INVERSION WHICH IS
NEARLY 5K FEET DEEP. THERE HAS ALSO BEEN SOME DRYING ALOFT WITH
PWAT NOW DOWN TO ABOUT 1.25 INCHES WHICH IS SLIGHTLY BELOW THE
AVERAGE FOR EARLY MAY. SO THE QUESTION IS HOW MUCH OF A FACTOR
WILL THESE TWO CONDITIONS HAVE ON CONVECTION DEVELOPING. THE LOW
LEVELS REMAIN SOMEWHAT UNSTABLE BUT THE OVERALL SOUNDING WOULD
MAKE ME BELIEVE THAT CONVECTION WILL STRUGGLE TO BUILD PAST THE
SHOWER STAGE. HOWEVER, MODEL FORECAST SOUNDINGS SHOW MID LEVEL
MOISTURE RETURN ALTHOUGH IT APPEARS THAT THEY MAY BE SUFFERING
FROM CONVECTIVE FEEDBACK. THE MORNING PROFILE ALSO INDICATES VERY
SLOW STORM MOTION TODAY AT UNDER 5 KNOTS WITH A DRIFT BACK TOWARDS
THE EAST COAST LATE IN THE DAY. THE EARLY MORNING HRRR RUNS
INITIALIZED NEARLY PERFECTLY AND SHOW INTERIOR CONVECTION
DEVELOPING OVER THE INTERIOR BETWEEN 17-18Z AND MOVING LITTLE. IT
WILL BE INTERESTING TO SEE WHAT THE LATER RUNS ILLUSTRATE AFTER IT
INGESTS THE 12Z SOUNDINGS. AT ANY RATE, FEEL THE NEED TO SCALE
BACK TO SLIGHT CHANCE THUNDER OVER THE INTERIOR AND CAN MAKE LATER
ASSESSMENTS AS THINGS MATERIALIZE.
KOB
PREV DISCUSSION... /ISSUED 334 AM EDT FRI MAY 10 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUED OVER THE ATLANTIC WATERS JUST
EAST OF THE MIAMI-DADE/BROWARD COUNTY BORDER. A FEW SHOWERS AND
THUNDERSTORMS HAVE ALSO DEVELOPED OVER THE METRO AREAS. THESE
SHOWERS AND STORMS ARE EXPECTED TO DIMINISH LATER THIS MORNING AS
A SHORTWAVE EXITS THE REGION.
UPPER RIDGING OVER THE CENTRAL GULF STRETCHING INTO THE LOWER
GREAT LAKES WILL SHIFT EAST TODAY AS A SHORTWAVE TROUGH MOVES FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY. UPPER HEIGHTS WILL
INCREASE OVER SOUTH FLORIDA...WITH MUCH WARMER AND SOMEWHAT DRIER
AIR ALOFT THAN ON THURSDAY. HOWEVER...LOW LEVEL MOISTURE WILL
REMAIN IN PLACE WITH DEWPOINTS IN THE MID 60S TO AROUND 70...SO
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG
THE SEA BREEZE BOUNDARIES ACROSS THE INTERIOR THIS AFTERNOON INTO
THE EARLY EVENING. A LIMITING FACTOR EACH DAY THROUGH THE WEEKEND
WILL BE THE SUBTROPICAL RIDGE OVER THE REGION...WITH WARM AND DRY
AIR FROM 850MB TO 600MB. EASTERLY LOW LEVEL FLOW AND LIGHT WINDS
ALOFT WILL ALLOW FOR SLOW STORM MOTION AND FOR STORMS TO STAY
ACROSS THE INTERIOR AND TOWARDS THE GULF COAST. TEMPERATURES WILL
BE WARM...WITH HIGHS IN THE MID 80S TO LOWER 90S. THE EASTERLY LOW
LEVEL FLOW WILL KEEP OVERNIGHT TEMPS WARM IN THE MID 60S TO THE
MID 70S. A FEW SHOWERS MAY DEVELOP OVERNIGHT ACROSS THE ATLANTIC
WATERS...AND MOVE TOWARDS THE EAST COAST.
ANOTHER UPPER LOW WILL MOVE SOUTHEAST ACROSS THE UPPER GREAT LAKES
ON SATURDAY...WITH THE TROUGH DIGGING INTO THE SOUTHEAST. THIS WILL
ALLOW LOW PRESSURE OVER THE NORTHEAST TO DEEPEN...AND A COLD FRONT
EXTENDING FROM THE LOW WILL PUSH INTO THE SOUTHEAST. DEEPER MOISTURE
WILL BEGIN TO POOL SOUTH OF THIS BOUNDARY OVER SOUTHERN GEORGIA AND
NORTHERN FLORIDA. THE UPPER RIDGE WILL FLATTEN AND PUSH SOUTH...AND
THIS SHOULD ALLOW FOR A LITTLE MORE ACTIVITY ALONG THE SEA BREEZE
BOUNDARIES ACROSS THE INTERIOR. SLOW STORM MOTION IS EXPECTED ONCE
AGAIN.
THE FRONTAL BOUNDARY WILL MOVE INTO NORTH AND CENTRAL FLORIDA ON
SUNDAY...AND SURFACE WINDS WILL SHIFT MORE TO THE SOUTH...WITH
SOUTHWEST TO WESTERLY FLOW ABOVE THE SURFACE. THE DRY AIR WILL
REMAIN IN THE LOW/MID LEVELS...SO POP GUIDANCE REMAINS LOW. THE
SURFACE BOUNDARY WILL MOVE INTO SOUTH FLORIDA OVERNIGHT SUNDAY INTO
MONDAY MORNING...WITH THE MOISTURE BOUNDARY LAGGING BEHIND INTO
CENTRAL FLORIDA. THE SURFACE FRONT WILL MOVE THROUGH THE REGION BY
EARLY AFTERNOON...WITH THE MOISTURE SCOURING OUT FROM NORTH TO SOUTH
BEGINNING MID/LATE AFTERNOON. SO RAIN CHANCES SHOULD BE CONFINED TO
THE SOUTHEASTERN HALF OF THE REGION...IF THE MOISTURE HANGS AROUND
AS THE MODELS INDICATE.
HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST ON TUESDAY...WITH DRIER
AIR AND NORTHEASTERLY FLOW. HIGH PRESSURE WILL THEN REMAIN IN
CONTROL OF THE WEATHER THROUGH THE END OF THE FORECAST PERIOD...WITH
DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. WITH MODERATE
NORTHEASTERLY FLOW TUESDAY AND WEDNESDAY...THERE WILL A HIGHER
THREAT FOR RIP CURRENTS ALONG THE ATLANTIC BEACHES.
MARINE...
LIGHT WINDS WITH SEAS BELOW 4 FT WILL CONTINUE THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
NIGHT INTO TUESDAY. WINDS WILL INCREASE OUT OF THE
NORTHEAST...WITH DETERIORATING MARINE CONDITIONS.
FIRE WEATHER...
MIN RH`S OVER THE WESTERN INTERIOR WILL BE IN THE
40 OVER THE NEXT COUPLE OF DAYS. THERE`S SOME RH`S NOW IN THE
UPPER 30S OVER THE WESTERN INTERIOR. A FEW TSTORMS WILL BE
POSSIBLE EACH OF THE NEXT FEW DAYS OVER THE INTERIOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 86 74 87 / 10 20 20 20
FORT LAUDERDALE 76 86 76 86 / 10 10 10 20
MIAMI 76 88 75 88 / 10 10 10 20
NAPLES 71 86 71 87 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1008 AM EDT FRI MAY 10 2013
.DISCUSSION...THE LOW LEVEL ATLANTIC RIDGE AXIS IS JUST NORTH OF THE
AREA BRINGING A LIGHT SOUTH-SOUTHEASTERLY FLOW ACROSS EAST CENTRAL
FLORIDA THIS MORNING. THIS WIND FLOW HAS TAPPED INTO THE MOISTER
ATMOSPHERE TO OUR SOUTH...BRINGING PWATS UP TO AROUND AN INCH ACROSS
THE NORTH THIS MORNING AND CLOSER TO 1.25" ACROSS THE TREASURE
COAST. HOWEVER THE SOUNDINGS SHOW CONSIDERABLE DRY AIR IN THE MID
LEVELS WITH THE CURRENT RUC ANALYSIS CAPPING 850-500MB RH VALUES AT
25-30 PERCENT. MOISTURE ADVECTION AT ALL LEVEL WILL CONTINUE
TODAY...THOUGH THE MID LEVELS WILL BE SLOWER TO INCREASE.
WITH THE DRIER AIR STILL IN PLACE...SHOWERS AND STORMS WILL BE SLOW
TO GET GOING TODAY THOUGH A FEW WILL BE POSSIBLE LATE THIS
MORNING/EARLY THIS AFTERNOON AS THE REMNANTS OF THE EARLIER ATLANTIC
ACTIVITY MOVE INTO THE COAST. ONE OR TWO MAY POP UP ON THE SEA
BREEZE THROUGH MID AFTERNOON...ESPECIALLY WHERE IT INTERACTIONS WITH
THE LAKE OKEECHOBEE BREEZE. HOWEVER THE BEST CHANCES WILL WAIT FOR
THE LATE AFTERNOON/EVENING COLLISION OF THE EAST AND WEST COAST SEA
BREEZES FROM LAKE GEORGE THROUGH THE ORLANDO METRO AND SOUTHWARDS TO
LAKE OKEECHOBEE. ANY CONVECTION THAT DEVELOPS FROM THE SEA BREEZE
COLLISION MAY SHIFT BACK TOWARD THE EAST COAST THIS
EVENING...ESPECIALLY NORTH OF THE CAPE. WARM TEMPS AND PARTLY SUNNY
SKIES EXPECTED FOR MUCH OF THE DAY WITH HIGHS REACHING THE MID 80S
AT THE COAST TO UPPER 80S/AROUND 90 DEGREES INLAND.
&&
.AVIATION...THROUGH 16Z...PREVAILING VFR WITH LCL CIGS FL020-030 IN
DEVELOPING CU ALONG COAST SOUTH OF KMLB. BRIEF -SHRA POSSIBLE SOUTH
OF KFPR. 16Z-21Z...ISOLD SHRA/TSRA DEVELOPING ALONG SEA BREEZE SOUTH
OF KTIX JUST INLAND FROM THE COAST. AFTER 21Z...SEA BREEZE COLLISION
TOWARD THE I-4 CORRIDOR AROUND SUNSET WILL BRING BEST CHANCE FOR
SHOWER/STORM DEVELOPMENT WITH TEMPO IFR/MVFR CONDS EXPECTED WITH
THIS ACTIVITY. A FEW STORMS WILL DRIFT BACK TOWARDS KDAB-KTIX LATE
IN THE EVENING.
&&
.MARINE...SOUTH-SOUTHEAST WINDS GENERALLY AROUND 10KTS THROUGH THE
PERIOD...CREEPING UP TO 10-15KTS NEAR THE COAST WITH THE AFTERNOON
SEA BREEZE DEVELOPMENT. SEAS 2-3 FEET. A FEW STORMS MAY DEVELOP
ALONG THE INTRACOASTAL WATERS THIS AFTERNOON AND MOVE OFFSHORE NORTH
OF THE CAPE THIS EVENING.
&&
.FIRE WEATHER...MIN RH MAY APPROACH AROUND 35 PERCENT FOR A FEW
HOURS FROM THE I-4 CORRIDOR WESTWARD THIS AFTERNOON BUT WINDS AND
ERC VALUES WILL REMAIN BELOW CRITICAL VALUES. A FEW LIGHTNING STORMS
EXPECTED TO DEVELOP FROM THE SEA BREEZE COLLISION ACROSS THE
INTERIOR AROUND SUNSET.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
MOSES/LASCODY
AREA FORECAST DISCUSSION
NWS MIAMI FL
1007 AM EDT FRI MAY 10 2013
.UPDATE...
LOOKING TO BE A VERY TRICKY FORECAST THIS MORNING. A WEAK MID
LEVEL TROUGH MOVED ACROSS SOUTH FLORIDA DURING THE LATE AFTERNOON
YESTERDAY AND LAST NIGHT SPARKING CONVECTION PARTICULARLY OFFSHORE
THIS MORNING WHICH THEN BUILT BACK ONSHORE. THAT CONVECTION HAS
NOW WANED AS THE TROUGH CONTINUES TO MOVE EAST. THE INTERESTING
PHENOMENA THIS MORNING IS THE 12Z MFL SOUNDING WHICH SHOWS
SIGNIFICANT WARMING AT 500 MB WITH A DISTINCT INVERSION WHICH IS
NEARLY 5K FEET DEEP. THERE HAS ALSO BEEN SOME DRYING ALOFT WITH
PWAT NOW DOWN TO ABOUT 1.25 INCHES WHICH IS SLIGHTLY BELOW THE
AVERAGE FOR EARLY MAY. SO THE QUESTION IS HOW MUCH OF A FACTOR
WILL THESE TWO CONDITIONS HAVE ON CONVECTION DEVELOPING. THE LOW
LEVELS REMAIN SOMEWHAT UNSTABLE BUT THE OVERALL SOUNDING WOULD
MAKE ME BELIEVE THAT CONVECTION WILL STRUGGLE TO BUILD PAST THE
SHOWER STAGE. HOWEVER, MODEL FORECAST SOUNDINGS SHOW MID LEVEL
MOISTURE RETURN ALTHOUGH IT APPEARS THAT THEY MAY BE SUFFERING
FROM CONVECTIVE FEEDBACK. THE MORNING PROFILE ALSO INDICATES VERY
SLOW STORM MOTION TODAY AT UNDER 5 KNOTS WITH A DRIFT BACK TOWARDS
THE EAST COAST LATE IN THE DAY. THE EARLY MORNING HRRR RUNS
INITIALIZED NEARLY PERFECTLY AND SHOW INTERIOR CONVECTION
DEVELOPING OVER THE INTERIOR BETWEEN 17-18Z AND MOVING LITTLE. IT
WILL BE INTERESTING TO SEE WHAT THE LATER RUNS ILLUSTRATE AFTER IT
INGESTS THE 12Z SOUNDINGS. AT ANY RATE, FEEL THE NEED TO SCALE
BACK TO SLIGHT CHANCE THUNDER OVER THE INTERIOR AND CAN MAKE LATER
ASSESSMENTS AS THINGS MATERIALIZE.
KOB
&&
.PREV DISCUSSION... /ISSUED 648 AM EDT FRI MAY 10 2013/
AVIATION...
WITH SURFACE HIGH PRESSURE WELL THE THE EAST NORTHEAST, THERE WILL
BE A SOUTHEASTERLY FLOW OVER SOUTH FLORIDA TODAY. THIS WILL ALSO
CONTINUE TO BRING IN SOME MOISTURE TO THE AREA. THIS COULD LEAD TO
AN AFTERNOON SHOWER OR THUNDERSTORM IN THE INTERIOR SECTIONS OF
SOUTH FLORIDA. HOWEVER, IT IS VERY UNCERTAIN IF ANY THUNDERSTORMS,
THAT MAY BE ABLE TO DEVELOP, WILL DRIFT CLOSE ENOUGH TO THE COAST
TO AFFECT ANY OF THE TAF SITES. SO, HAVE NOT MENTIONED THEM AS OF
YET IN THE TAFS. GIVEN THIS, A VFR DAY IS EXPECTED WITH WINDS FROM
THE SE AROUND 10 KTS, BECOMING LIGHT AND VARIABLE IN THE LATE
EVENING.
PREV DISCUSSION... /ISSUED 334 AM EDT FRI MAY 10 2013/
DISCUSSION...
SHOWERS AND THUNDERSTORMS CONTINUED OVER THE ATLANTIC WATERS JUST
EAST OF THE MIAMI-DADE/BROWARD COUNTY BORDER. A FEW SHOWERS AND
THUNDERSTORMS HAVE ALSO DEVELOPED OVER THE METRO AREAS. THESE
SHOWERS AND STORMS ARE EXPECTED TO DIMINISH LATER THIS MORNING AS
A SHORTWAVE EXITS THE REGION.
UPPER RIDGING OVER THE CENTRAL GULF STRETCHING INTO THE LOWER
GREAT LAKES WILL SHIFT EAST TODAY AS A SHORTWAVE TROUGH MOVES FROM
THE CENTRAL PLAINS INTO THE OHIO VALLEY. UPPER HEIGHTS WILL
INCREASE OVER SOUTH FLORIDA...WITH MUCH WARMER AND SOMEWHAT DRIER
AIR ALOFT THAN ON THURSDAY. HOWEVER...LOW LEVEL MOISTURE WILL
REMAIN IN PLACE WITH DEWPOINTS IN THE MID 60S TO AROUND 70...SO
ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG
THE SEA BREEZE BOUNDARIES ACROSS THE INTERIOR THIS AFTERNOON INTO
THE EARLY EVENING. A LIMITING FACTOR EACH DAY THROUGH THE WEEKEND
WILL BE THE SUBTROPICAL RIDGE OVER THE REGION...WITH WARM AND DRY
AIR FROM 850MB TO 600MB. EASTERLY LOW LEVEL FLOW AND LIGHT WINDS
ALOFT WILL ALLOW FOR SLOW STORM MOTION AND FOR STORMS TO STAY
ACROSS THE INTERIOR AND TOWARDS THE GULF COAST. TEMPERATURES WILL
BE WARM...WITH HIGHS IN THE MID 80S TO LOWER 90S. THE EASTERLY LOW
LEVEL FLOW WILL KEEP OVERNIGHT TEMPS WARM IN THE MID 60S TO THE
MID 70S. A FEW SHOWERS MAY DEVELOP OVERNIGHT ACROSS THE ATLANTIC
WATERS...AND MOVE TOWARDS THE EAST COAST.
ANOTHER UPPER LOW WILL MOVE SOUTHEAST ACROSS THE UPPER GREAT LAKES
ON SATURDAY...WITH THE TROUGH DIGGING INTO THE SOUTHEAST. THIS WILL
ALLOW LOW PRESSURE OVER THE NORTHEAST TO DEEPEN...AND A COLD FRONT
EXTENDING FROM THE LOW WILL PUSH INTO THE SOUTHEAST. DEEPER MOISTURE
WILL BEGIN TO POOL SOUTH OF THIS BOUNDARY OVER SOUTHERN GEORGIA AND
NORTHERN FLORIDA. THE UPPER RIDGE WILL FLATTEN AND PUSH SOUTH...AND
THIS SHOULD ALLOW FOR A LITTLE MORE ACTIVITY ALONG THE SEA BREEZE
BOUNDARIES ACROSS THE INTERIOR. SLOW STORM MOTION IS EXPECTED ONCE
AGAIN.
THE FRONTAL BOUNDARY WILL MOVE INTO NORTH AND CENTRAL FLORIDA ON
SUNDAY...AND SURFACE WINDS WILL SHIFT MORE TO THE SOUTH...WITH
SOUTHWEST TO WESTERLY FLOW ABOVE THE SURFACE. THE DRY AIR WILL
REMAIN IN THE LOW/MID LEVELS...SO POP GUIDANCE REMAINS LOW. THE
SURFACE BOUNDARY WILL MOVE INTO SOUTH FLORIDA OVERNIGHT SUNDAY INTO
MONDAY MORNING...WITH THE MOISTURE BOUNDARY LAGGING BEHIND INTO
CENTRAL FLORIDA. THE SURFACE FRONT WILL MOVE THROUGH THE REGION BY
EARLY AFTERNOON...WITH THE MOISTURE SCOURING OUT FROM NORTH TO SOUTH
BEGINNING MID/LATE AFTERNOON. SO RAIN CHANCES SHOULD BE CONFINED TO
THE SOUTHEASTERN HALF OF THE REGION...IF THE MOISTURE HANGS AROUND
AS THE MODELS INDICATE.
HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST ON TUESDAY...WITH DRIER
AIR AND NORTHEASTERLY FLOW. HIGH PRESSURE WILL THEN REMAIN IN
CONTROL OF THE WEATHER THROUGH THE END OF THE FORECAST PERIOD...WITH
DRY CONDITIONS AND NEAR NORMAL TEMPERATURES. WITH MODERATE
NORTHEASTERLY FLOW TUESDAY AND WEDNESDAY...THERE WILL A HIGHER
THREAT FOR RIP CURRENTS ALONG THE ATLANTIC BEACHES.
MARINE...
LIGHT WINDS WITH SEAS BELOW 4 FT WILL CONTINUE THROUGH
THE WEEKEND. A COLD FRONT WILL MOVE THROUGH THE REGION MONDAY
NIGHT INTO TUESDAY. WINDS WILL INCREASE OUT OF THE
NORTHEAST...WITH DETERIORATING MARINE CONDITIONS.
FIRE WEATHER...
MIN RH`S OVER THE WESTERN INTERIOR WILL BE IN THE
40 OVER THE NEXT COUPLE OF DAYS. THERE`S SOME RH`S NOW IN THE
UPPER 30S OVER THE WESTERN INTERIOR. A FEW TSTORMS WILL BE
POSSIBLE EACH OF THE NEXT FEW DAYS OVER THE INTERIOR.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 73 86 74 / 10 10 20 20
FORT LAUDERDALE 86 76 86 76 / 20 10 10 10
MIAMI 87 76 88 75 / 20 10 10 10
NAPLES 87 71 86 71 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1154 AM MDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 1146 AM MDT FRI MAY 10 2013
WEAK SHORTWAVE TROUGH ALONG WITH STEEP LAPSE RATES...SOME CAPE AND
NO INHIBITION HAVE ALLOW THUNDERSTORMS TO DEVELOP MORE RAPIDLY AND
FURTHER SOUTH THAN PREVIOUSLY DEPICTED. HRRR WAS NOT DOING TOO BAD
EVEN THOUGH IT DID NOT START FAST...IN CATCHES UP RAPIDLY THOUGH...
USED IT AND REALITY TO INCREASE CHANCE AND COVERAGE OF
THUNDERSTORMS ACROSS THE ENTIRE AREA THROUGH THE REST OF THE
AFTERNOON. TEMPERATURES MAY BE A TAD WARM DUE TO EARLIER ONSET OF
CONVECTION BUT STILL LOOK REASONABLE.
&&
.SHORT TERM...(TODAY THROUGH SUNDAY NIGHT)
ISSUED AT 200 AM MDT FRI MAY 10 2013
TODAY-TONIGHT...A WEAK WEATHER DISTURBANCE PRESENTLY ACROSS
SOUTHEAST WYOMING/WESTERN NEBRASKA WILL MOVE THROUGH THE AREA
TODAY PRODUCING A FEW SHOWERS AND POSSIBLE THUNDERSTORMS. THIS
FEATURE IS EXPECTED TO BE OUT OF THE AREA TONIGHT. A COLD FRONT
WILL MOVE SOUTH ACROSS THE AREA SHORTLY AFTER MIDNIGHT. NO
PRECIPITATION IS EXPECTED WITH THE FRONT. HIGHS GENERALLY IN THE
LOW 70S...EXCEPTION BEING FLAGLER AREA WITH MID 60S. LOWS IN THE 40S.
SATURDAY-SATURDAY NIGHT...SURFACE HIGH MOVES IN BEHIND THE FRONT
BRINGING SLIGHTLY COOLER TEMPERATURES. MODELS CONTINUE TO INDICATE
ANOTHER WEATHER DISTURBANCE TO MOVE INTO EASTERN COLORADO DURING
THE AFTERNOON CONTINUING EAST/SOUTHEAST ACROSS MUCH OF THE AREA
SATURDAY NIGHT. WILL MAINTAIN SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS. HIGHS 65 TO 70...LOWS IN THE LOW TO MID 40S.
SUNDAY-SUNDAY NIGHT...DRY AND WARMER. HIGHS LOW 70S EAST...MID 70S
TO AROUND 80 WEST. LOWS 45 TO 50.
.LONG TERM...(MONDAY THROUGH THURSDAY)
ISSUED AT 200 AM MDT FRI MAY 10 2013
DRY AND MILD EARLY IN THE WEEK...WITH CHANCES FOR STORMS INCREASING
BY MID-WEEK. MUCH UNCERTAINTY IN THE EXACT SYNOPTIC SET-UP...BUT
BELIEVE CONDITIONS WILL BE ADEQUATE TO SUPPORT PRECIP OVER THE
LATER PORTION OF THE WEEK.
MONDAY AND TUESDAY...ALL GUIDANCE CONTINUES TO BE CONSISTENT IN
PROJECTING 850MB TEMPS IN EXCESS OF +25C...WHICH WOULD BE
CONSIDERED WARM FOR JULY LET ALONE MAY. EXPECTING HIGHS TO BE NEAR
90 ON BOTH DAYS...WHICH IS APPROACH RECORD LEVELS. WHILE TUESDAY
HAS SEEMED LIKE THE SLIGHTLY WARMER DAY OF THE TWO FOR THE PAST
FEW SHIFTS...INCREASED CLOUD COVER AS THE GFS IS HINTING TOWARDS
COULD LIMIT TEMPS. CONFIDENCE IS NORMAL TO ABOVE NORMAL.
TUESDAY NIGHT THROUGH THURSDAY...A MORE ACTIVE WEATHER PATTERN
WILL DEVELOP ACROSS THE MIDDLE OF THE WEEK. A WEAK UPPER LOW OVER
THE SOUTHERN CONUS WILL EVOLVE INTO A SLIGHTLY NEGATIVE TROUGH AND
MOVE NORTH ON TUESDAY INTO WEDNESDAY...THEN GRADUALLY MOVE EAST ON
THURSDAY. COULD SEE A FEW SHOWERS/STORMS DEVELOPING ON TUESDAY
NIGHT...BUT THE BETTER CHANCE FOR PRECIP WILL BE ON WED AND THURS
AFTERNOON/EARLY EVENING. TEMPS WED/THU WILL BE DEPENDENT ON CLOUD
COVER...AND WITH MODEL INCONSISTENCY DECIDED TO JUST STICK WITH
THE ALLBLEND /AVERAGE OF ALL MODELS/ GUIDANCE. CONFIDENCE OVER
THIS PERIOD IS NORMAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1146 AM MDT FRI MAY 10 2013
CONVECTION HAS ALREADY DEVELOPED ACROSS THE AREA. EVEN THOUGH HAVE
INSERTED A CHANCE OF TSRA AT BOTH SITES...KGLD WILL HAVE THE BEST
CHANCE AND COULD POSSIBLY BECOME MVFR IF ONE OF THE STRONGER
STORMS MOVES ACROSS...BASED ON LATEST GUIDANCE AND WHAT HAPPENED
YESTERDAY. ACTIVITY SHOULD END QUICKLY AFTER 00Z. COLD FRONT WILL
MOVE THROUGH AFTER 06Z AND CAUSE GUSTY NORTHERLY WINDS THROUGH THE
REST OF THE PERIOD. OUTSIDE OF THUNDERSTORM ACTIVITY...VFR
CONDITIONS ARE EXPECTED THE REST OF THE PERIOD.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...99
LONG TERM...JJM
AVIATION...BULLER
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1217 AM CDT FRI MAY 10 2013
...UPDATED FOR THE 06Z TAFS AND AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 221 PM CDT THU MAY 9 2013
AN ELONGATED MID LEVEL VORTICITY AXIS WAS FOUND ACROSS THE CENTRAL
PLAINS TODAY COMPLETE WITH MOISTURE AND FAIRLY COOL TEMPERATURES.
UPPER AIR OBSERVATIONS AND RAP ANALYSIS INDICATED 500/700MB
TEMPERATURES AROUND -17C/0C RESPECTIVELY. SOME INSOLATION THROUGH
EARLY AFTERNOON RESULTED IN SURFACE TEMPERATURES WARMING INTO THE
UPPER 60S TO NEAR 70 DEGREES PARTICULARLY SOUTH OF THE ARKANSAS
RIVER. THE MID LEVEL MOISTURE AXIS WAS FOUND TO BE CENTERED FROM THE
CENTRAL ROCKIES THROUGH NORTHERN KANSAS AND MUCH OF NEBRASKA. THIS
LINED UP FAIRLY WELL WITH THE MEAN 500-700MB DEFORMATION AXIS. THE
SURFACE FRONT HAD PUSHED WELL SOUTH OF THE REGION DOWN INTO SOUTHERN
OKLAHOMA, SO SURFACE-BASED INSTABILITY WAS VERY LOW ACROSS
SOUTHWESTERN KANSAS.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 221 PM CDT THU MAY 9 2013
THE MAIN FORECAST CHALLENGE IS PRECIPITATION CHANCES, COVERAGE, AND
INTENSITY THIS EVENING. THE MENTIONED DEFORMATION AXIS WILL LINGER
ACROSS SOUTHEASTERN COLORADO AND WESTERN KANSAS THROUGH THIS
EVENING. THE UPDATED FORECAST POP/WX GRIDS WILL REFLECT THE HRRR
MODEL THINKING OF WEAK UPRIGHT CONVECTION FORMING NEAR A VORTICITY
CENTER ACROSS SOUTHEASTERN COLORADO. A LOOSELY ORGANIZED CLUSTER OF
CONVECTION COULD DEVELOP A COLD POOL ALLOWING THE CLUSTER OF
CONVECTION TO MOVE INTO THE SOUTHWESTERN QUARTER OR THIRD OF THE DDC
FORECAST AREA (SOUTH AND WEST OF A LAKIN TO MEADE LINE, ROUGHLY).
THE ABSENCE OF APPRECIABLE SURFACE-BASED CAPE IS EXPECTED TO KEEP
CONVECTION BELOW SEVERE LIMITS...BUT SOME GUSTS TO 50 OR 55 MPH WILL
BE POSSIBLE IF LOOSELY ORGANIZED COLD POOLS DEVELOP. ANY STORMS
WHICH IMPACT FAR SOUTHWESTERN KANSAS SHOULD BE EXITING THE AREA BY
LATE EVENING.
ON FRIDAY...WESTERN KANSAS WILL BE UNDER AN INCREASED INFLUENCE OF
NORTHWEST FLOW ALOFT AS THE MID LEVEL SHEAR AXIS CONTINUES TO PUSH
SOUTH INTO TEXAS. THIS IS EXPECTED TO RESULT IN MORE TRANQUIL
SENSIBLE WEATHER. THAT BEING SAID...MID LEVEL TEMPERATURES WILL
STILL BE COOL (700MB TEMPERATURE -2 TO 0C)...AND MIXING
CONDENSATION LEVELS WILL BE LOW AS INSOLATION ALLOWS SURFACE TEMPS
TO WARM INTO THE UPPER 60S. THE RESULT WILL BE DEVELOPMENT OF
CUMULUS AND PERHAPS AN ISOLATED SHOWER OR TO LATE IN THE DAY. THE
OFFICIAL FORECAST WILL BE DRY AS THERE WILL BE AN ABSENCE OF UPPER
LEVEL FORCING FOR ASCENT TO PROMOTE ANY ORGANIZATION OF
CONVECTION.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 335 PM CDT THU MAY 9 2013
THE WEATHER PICTURE THIS WEEKEND WILL DEPICT AN UPPER LEVEL LONG
WAVE TROUGH DIGGING ACROSS THE NORTHEAST UNITED STATES AND AN UPPER
LEVEL RIDGE BUILDING ACROSS THE WESTERN UNITED STATES. MEANWHILE,
THE UPPER LEVEL LOW THAT ASSISTED IN SEVERE STORM DEVELOPMENT ACROSS
OUR AREA THE LAST COUPLE OF NIGHTS WILL SPLIT OFF FROM THE FLOW AND
MIGRATE TOWARDS NORTHERN MEXICO. THESE FEATURES WILL PLACE THE
CENTRAL HIGH PLAINS UNDER NORTHWEST FLOW ALOFT. THIS PATTERN USUALLY
GIVES WAY TO FAIR WEATHER DAYS ACROSS WESTERN KANSAS. HOWEVER, RAIN
CHANCES WILL BE POSSIBLE SATURDAY NIGHT INTO SUNDAY. HIGH PRESSURE
AT THE SURFACE WILL BE THE DOMINATE FEATURE ACROSS WESTERN KANSAS
FRIDAY NIGHT INTO SATURDAY WITH A SECOND AREA OF HIGH PRESSURE
OOZING DOWN FROM THE NORTH SATURDAY NIGHT INTO SUNDAY. A COLD FRONT
WILL BE FOUND IN BETWEEN THESE TWO AREAS OF HIGH PRESSURE ALLOWING
SOME LIFT TO OCCUR ACROSS THE PLAINS SATURDAY NIGHT. THE ATMOSPHERE
WILL BE FAIRLY DRY AS THIS FRONT MOVES THROUGH BUT THERE COULD BE A
SHOWER OR TWO THAT FORMS SATURDAY NIGHT INTO EARLY SUNDAY MORNING.
WINDS WILL GENERALLY BE LIGHT AND VARIABLE FRIDAY NIGHT INTO
SATURDAY SHIFTING TO THE NORTH BEHIND THE FRONT SATURDAY NIGHT INTO
SUNDAY. A WEAK UPPER LEVEL SHORTWAVE IS THEN DEPICTED BY THE MODELS
TO MOVE DOWN THROUGH THE NORTHWEST FLOW AND INTO KANSAS SUNDAY. IF
THIS COMES TO FRUITION, THUNDERSTORM WILL BE POSSIBLE ACROSS CENTRAL
KANSAS SUNDAY MORNING SPREADING TOWARDS SOUTH CENTRAL KANSAS AS THE
DAY PROGRESSES. OTHERWISE PARTLY CLOUDY SKIES WILL BE FOUND ACROSS
WESTERN KANSAS. LEE TROUGHING WILL ALSO BE DEVELOPING ACROSS THE
KS/CO BORDER DURING THIS TIME FRAME SHIFTING WINDS TO MORE OF A
SOUTHERLY DIRECTION. LOWS SATURDAY AND SUNDAY MORNING LOOK TO DIP
INTO THE 40S WITH HIGHS IN THE 70S SATURDAY AND SUNDAY AFTERNOON.
THE UPPER LEVEL RIDGE ACROSS THE WESTERN UNITED STATES WILL THEN
SHIFT EASTWARD INTO THE ROCKIES AND PLAINS DURING THE FIRST PART OF
NEXT WEEK. THIS FEATURE IN CONJUNCTION WITH SURFACE HIGH PRESSURE
LOCATED EAST OF KANSAS WILL BRING MOSTLY CLEAR SKIES AND DRY
CONDITIONS TO WESTERN KANSAS. LEE TROUGHING ACROSS EASTERN COLORADO
WILL CONTINUE AND BRING WARM TEMPERATURES TO THE AREA. HIGHS MONDAY
ARE FORECASTED TO REACH INTO THE 80S WITH HIGHS AROUND 90 DEGREES ON
TUESDAY. LOWS WILL GENERALLY BE IN THE 50S MONDAY AND TUESDAY
MORNING.
MID RANGE MODELS THEN SUGGEST THE UPPER LEVEL LOW ACROSS NORTHERN
MEXICO TO MOVE BACK NORTHEAST TO THE SOUTHERN PLAINS. THIS WOULD
BRING INCREASING CHANCES OF THUNDERSTORMS TO PARTS OF KANSAS MID
WEEK INTO THE FIRST PART OF THE WEEKEND. HIGHS DURING THIS TIME
FRAME WILL GENERALLY BE IN THE 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1212 AM CDT FRI MAY 10 2013
A LONG TROUGH OF UPPER LEVEL LOW PRESSURE STRETCHED FROM NORTHEAST
TO SOUTHWEST ACROSS WESTERN KANSAS THIS MORNING. SOME
STRATOCUMULUS CLOUDS HAVE ADVECTED INTO THE KHYS TAF SITE, AND
CIGS THERE SHOULD STAY IN THE MVFR CATEGORY AROUND OVC025 THROUGH
10Z OR SO. AFTER 10Z, EXPECT MVFR CIGS AT ALL THREE TAF SITES, IN
THE BKN-OVC035-040 RANGE. WHEN WINDS SHIFT MORE TO THE NORTHEAST
LATER THIS AFTERNOON, CLOUDS SHOULD SCATTER OUT IN THE 060-070
FOOT RANGE. CLOUDS WILL DECREASE EVEN MORE TOWARD SUNSET, AND
WINDS WILL AGAIN BECOME LIGHT AND VARIABLE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 48 71 45 73 / 10 20 10 10
GCK 47 70 46 75 / 10 20 10 10
EHA 47 71 49 78 / 10 20 10 10
LBL 48 73 48 78 / 10 20 10 10
HYS 48 68 43 69 / 20 20 20 20
P28 50 73 48 70 / 10 20 20 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...HOVORKA_42
AVIATION...BURKE
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1118 PM EDT SAT MAY 11 2013
.UPDATE...
ISSUED AT 1115 PM EDT SAT MAY 11 2013
A RECENT UPDATE WAS MADE TO THE GRIDS TO FINE TUNE TIMING OF SHOWER
CHANCES OVER THE NEXT FEW HOURS AND FRESHEN UP HOURLY
TEMPS...DEWPOINTS AND WINDS. THE COLD FRONT IS NOW MOVING THROUGH
CENTRAL KY WITH A BAND OF SHOWERS PRECEDING IT. COLDER AND DRIER AIR
WILL MOVE INTO THE AREA LATER TONIGHT BEHIND THE FRONT.
UPDATE ISSUED AT 810 PM EDT SAT MAY 11 2013
AT PRESENT...SOUTH CENTRAL AND EASTERN KY ARE IN A LULL BETWEEN THE
DEPARTED INITIAL FIRST COLD FRONT AND THE STRONGER SECOND COLD FRONT.
THIS COLD FRONT IS THE LEADING EDGE OF A MUCH COLDER AND DRIER
AIRMASS. ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY ALONG THE
BOUNDARY...BUT OPERATIONAL MODELS INCLUDING THE HRRR AND NAM SHOW SOME
DECREASE IN ACTIVITY ALONG THE BOUNDARY WITH LOSS OF DAYTIME HEATING.
EXTRAPOLATION AND OPERATIONAL MODELS GENERALLY BRING THESE INTO THE
WESTERN COUNTIES AROUND OR A LITTLE BEFORE MIDNIGHT AND THEN DURING
THE OVERNIGHT HOURS ACROSS THE EASTERN HALF OF THE CWA. FEW CHANGES
WERE NEEDED TO THE PREVIOUS TIMING AND THE RECENT UPDATE WAS MAINLY
TO REMOVE AFTERNOON REFERENCES FROM THE ZFP AND ADJUST HOURLY
TEMPS...DEWPOINTS...SKY AND WINDS TO REFLECT RECENT TRENDS. THIS
SCENARIO BRING SOME PARTIAL CLEARING ACROSS THE CWA FOR AN HOUR OR
TWO BEFORE MORE CLOUDS MOVE IN ALONG THE BOUNDARY. ALTHOUGH THE
CURRENT BAND OF CLOUDS IS RATHER NARROW POST FRONTAL FLOW THAT IS OUT
OF THE NORTHWEST SHOULD TEND TO LINGER CLOUDS A LITTLE LONGER THAN
BAND OF CLOUDS TO THE WEST WOULD INDICATE AND THIS WAS ALREADY
HANDLED WELL IN THE PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 354 PM EDT SAT MAY 11 2013
ISOLATED TO SCATTERED SHOWERS WILL WIND DOWN OVER THE NEXT COUPLE OF
HOURS AS THE SURFACE COLD FRONT HAS SHIFTED OFF TO THE SOUTHEAST OF
THE AREA. THE NEXT COLD FRONT IS CURRENTLY ALIGNED FROM NORTHEAST
INDIANA DOWN THROUGH SOUTHEAST MISSOURI. MOST OF THE SHOWER ACTIVITY
ASSOCIATED WITH THIS BOUNDARY IS LOCATED NORTH OF THE OHIO RIVER.
THE MODELS ARE IN GOOD AGREEMENT WITH BRINGING THIS SECONDARY
BOUNDARY THROUGH THE AREA LATER THIS EVENING...WITH ISOLATED TO
SCATTERED SHOWERS THREATENING ONCE AGAIN...ALTHOUGH MOST GUIDANCE
INDICATES A DOWNTREND IN CONVECTION AS THE BOUNDARY MOVES ACROSS
EASTERN KENTUCKY. LOWS TONIGHT WILL BOTTOM IN THE LOW TO MID 40S FOR
MOST LOCATIONS.
AFTER AN UNSEASONABLY COOL MOTHER/S DAY WITH HIGHS TOPPING OUT AT
AROUND 60 DEGREES...A CHILLY SUNDAY NIGHT WILL BE IN STORE. THE MODEL
GUIDANCE CONTINUES TO SHOW NEAR RECORD LOWS OF LOWER TO MIDDLE 30S.
HAVE THEREFORE HIGHLIGHTED THE COOLER TEMPERATURES AND THE
POSSIBILITY OF FROST IN AN SPS...ALTHOUGH WITH THE GREEN PRETTY MUCH
IN FULL SWING AND SATURATED GROUND FROM RECENT RAINFALL...THE FOG MAY
WIND UP BEING MORE PREVALENT THAN THE FROST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM EDT SAT MAY 11 2013
THE MODELS START OUT THE EXTENDED IN EXCELLENT AGREEMENT ALOFT AS
THEY ALL HAVE A DEEP TROUGH EXTENDING FROM THE GREAT LAKES...
THROUGH THE OHIO VALLEY...AND TO THE DEEP SOUTH. THIS TROUGH WILL
QUICKLY PULL EAST DURING THE DAY MONDAY ALLOWING HEIGHTS TO RISE
OVER EAST KENTUCKY INTO MONDAY NIGHT. MODERATE RIDGING WILL THEN
BUILD INTO THE STATE FROM THE WEST AND LATER NORTH FROM THE CENTRAL
GULF COAST. BY WEDNESDAY MORNING...THOUGH...SOME DISTINCT
DIFFERENCES START TO CROP UP AMONGST THE MODELS IN BOTH THE NORTHERN
AND SOUTHERN STREAMS. A WELL DEFINED MID LEVEL LOW RUNNING EAST
ALONG THE CANADIAN BORDER...IN THE GFS...IS REPRESENTED AS A
WEAKER...MORE PROGRESSIVE...OPEN WAVE IN THE 00Z ECMWF. THE LATEST
GEM APPEARS TO BE SIDING WITH THE GFS WITH THIS FEATURE. THE NET
RESULT FOR EAST KENTUCKY WILL BE SIMILAR REGARDLESS OF WHICH SOLUTION
PANS OUT AS THERE REMAINS GOOD AGREEMENT THAT RIDGING WILL BE IN
PLACE OVER OUR AREA THROUGH MIDWEEK. WHILE THE NORTHERN DETAILS WORK
THEMSELVES OUT...TO THE SOUTH A WEAKENING IMPULSE WILL MOVE THROUGH
THE SOUTHERN PLAINS LIKELY SERVING TO SUPPRESS THE LOCAL RIDGING AS
IT MOVES CLOSER TO THE CWA ON THURSDAY. IN FACT...BY 00Z FRIDAY THE
GFS IS SHOWING A FLAT TO SLIGHTLY TROUGHING PATTERN OVER EAST
KENTUCKY WHILE THE ECMWF STILL HAS THE BACK EDGE OF RIDGING HOLDING
ON THROUGH THE APPALACHIANS. DESPITE THE PATTERN DIFFERENCES...THE
HEIGHTS ARE RATHER SIMILAR OVER THE AREA INTO FRIDAY...ALONG WITH A
HEALTHY MIX OF ENERGY...KEEPING THINGS UNSETTLED. FOR SATURDAY...
WEAK RIDGING WILL REMAIN IN PLACE THROUGH THE AREA AS ANY IMPRESSIVE
WAVES STAY WELL NORTH OF THE AREA...MORE BEFITTING OF THIS TIME OF
YEAR. GIVEN THE SIMILARITY AND GENERAL CONSENSUS EXHIBITED BY THE
MODELS OVER EAST KENTUCKY THROUGH THE PERIOD...WILL FOLLOW A BLENDED
SOLUTION WITH LITTLE APPREHENSION...AND SOME CONFIDENCE THAT A MORE
NORMAL LATE SPRING WX PATTERN IS NEARLY UPON US.
AS FOR SENSIBLE WEATHER...MONDAY WILL START OUT CHILLY AND FROSTY
BUT MODERATE QUICKLY A HIGH PRESSURE MOVES INTO THE OHIO VALLEY. THE
WARMING WILL CONTINUE INTO TUESDAY AS A WARM FRONT PASSES TO THE
NORTH OF THE AREA. THIS WILL SET THE STAGE FOR A RARITY OF THIS
SPRING...A DAY OF ABOVE NORMAL TEMPERATURES...ON WEDNESDAY. ABOUT
THIS TIME A DEVELOPING FRONT SETS UP NORTH OF THE OHIO RIVER AND
INCREASING MOISTURE WILL BRING WITH IT BETTER CHANCES FOR CONVECTION
ON THURSDAY. THIS NEARBY FRONT...A MOIST BOUNDARY LAYER...AND WARM
TEMPERATURES WILL LIKELY KEEP...AT LEAST DIURNALLY DRIVEN...SHOWERS
AND THUNDERSTORMS AROUND THROUGH THE END OF THE WEEK AND INTO
SATURDAY. THE PRICE OF A MORE NORMAL SPRING PATTERN...AND A LACK OF
STRONG HIGH PRESSURE...DURING THE LATTER PART OF THE FORECAST WILL
BE A PATTERN MORE SIMILAR TO EARLY SUMMER MAKING AFTERNOON AND
EVENING CONVECTION A GOOD BET.
THE CR GRID LOAD CAME IN PRETTY GOOD...DID MAKE HOURLY ADJUSTMENTS
TO THE POPS AND SKY COVER TO BETTER HONE IN ON THE TIMES OF PEAK
CONVECTION FROM THURSDAY ON. ALSO...MADE SOME TERRAIN BASED
ADJUSTMENTS TO LOW TEMPERATURES EACH NIGHT FROM MONDAY THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 815 PM EDT SAT MAY 11 2013
DURING THE FIRST 3 TO 7 HOURS OF THE PERIOD...THE REGION WILL BE A
RELATIVE LULL IN CLOUDS BETWEEN THE DEPARTED COLD FRONT AND ANOTHER
APPROACHING COLD FRONT AND ASSOCIATED BAND OF CLOUDS AND SCATTERED
SHOWERS. DURING THE LULL AN IMPROVEMENT TO VFR SHOULD OCCUR IN ALL
BUT THE HIGHEST TERRAIN THE SOUTHEAST WHERE SKIES SHOULD IMPROVE TO
MVFR FROM IFR. A DROP DOWN TO MVFR OR PERHAPS LOWER IS ANTICIPATED
ALONG AND FOR ABOUT 3 HOURS BEHIND THE BOUNDARY. DRY AIR ADVECTION IN
LOWER LEVELS SHOULD LEAD TO IMPROVEMENTS BACK TO VFR AFTER THAT PERIOD.
WINDS WILL BE A BIT GUSTY FROM NW OR NNW...ESPECIALLY 15Z TO 22Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GEOGERIAN
LONG TERM...GREIF
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
815 PM EDT SAT MAY 11 2013
.UPDATE...
ISSUED AT 810 PM EDT SAT MAY 11 2013
AT PRESENT...SOUTH CENTRAL AND EASTERN KY ARE IN A LULL BETWEEN THE
DEPARTED INITIAL FIRST COLD FRONT AND THE STRONGER SECOND COLD FRONT.
THIS COLD FRONT IS THE LEADING EDGE OF A MUCH COLDER AND DRIER
AIRMASS. ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY ALONG THE
BOUNDARY...BUT OPERATIONAL MODELS INCLUDING THE HRRR AND NAM SHOW SOME
DECREASE IN ACTIVITY ALONG THE BOUNDARY WITH LOSS OF DAYTIME HEATING.
EXTRAPOLATION AND OPERATIONAL MODELS GENERALLY BRING THESE INTO THE
WESTERN COUNTIES AROUND OR A LITTLE BEFORE MIDNIGHT AND THEN DURING
THE OVERNIGHT HOURS ACROSS THE EASTERN HALF OF THE CWA. FEW CHANGES
WERE NEEDED TO THE PREVIOUS TIMING AND THE RECENT UPDATE WAS MAINLY
TO REMOVE AFTERNOON REFERENCES FROM THE ZFP AND ADJUST HOURLY
TEMPS...DEWPOINTS...SKY AND WINDS TO REFLECT RECENT TRENDS. THIS
SCENARIO BRING SOME PARTIAL CLEARING ACROSS THE CWA FOR AN HOUR OR
TWO BEFORE MORE CLOUDS MOVE IN ALONG THE BOUNDARY. ALTHOUGH THE
CURRENT BAND OF CLOUDS IS RATHER NARROW POST FRONTAL FLOW THAT IS OUT
OF THE NORTHWEST SHOULD TEND TO LINGER CLOUDS A LITTLE LONGER THAN
BAND OF CLOUDS TO THE WEST WOULD INDICATE AND THIS WAS ALREADY
HANDLED WELL IN THE PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 354 PM EDT SAT MAY 11 2013
ISOLATED TO SCATTERED SHOWERS WILL WIND DOWN OVER THE NEXT COUPLE OF
HOURS AS THE SURFACE COLD FRONT HAS SHIFTED OFF TO THE SOUTHEAST OF
THE AREA. THE NEXT COLD FRONT IS CURRENTLY ALIGNED FROM NORTHEAST
INDIANA DOWN THROUGH SOUTHEAST MISSOURI. MOST OF THE SHOWER ACTIVITY
ASSOCIATED WITH THIS BOUNDARY IS LOCATED NORTH OF THE OHIO RIVER.
THE MODELS ARE IN GOOD AGREEMENT WITH BRINGING THIS SECONDARY
BOUNDARY THROUGH THE AREA LATER THIS EVENING...WITH ISOLATED TO
SCATTERED SHOWERS THREATENING ONCE AGAIN...ALTHOUGH MOST GUIDANCE
INDICATES A DOWNTREND IN CONVECTION AS THE BOUNDARY MOVES ACROSS
EASTERN KENTUCKY. LOWS TONIGHT WILL BOTTOM IN THE LOW TO MID 40S FOR
MOST LOCATIONS.
AFTER AN UNSEASONABLY COOL MOTHER/S DAY WITH HIGHS TOPPING OUT AT
AROUND 60 DEGREES...A CHILLY SUNDAY NIGHT WILL BE IN STORE. THE MODEL
GUIDANCE CONTINUES TO SHOW NEAR RECORD LOWS OF LOWER TO MIDDLE 30S.
HAVE THEREFORE HIGHLIGHTED THE COOLER TEMPERATURES AND THE
POSSIBILITY OF FROST IN AN SPS...ALTHOUGH WITH THE GREEN PRETTY MUCH
IN FULL SWING AND SATURATED GROUND FROM RECENT RAINFALL...THE FOG MAY
WIND UP BEING MORE PREVALENT THAN THE FROST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM EDT SAT MAY 11 2013
THE MODELS START OUT THE EXTENDED IN EXCELLENT AGREEMENT ALOFT AS
THEY ALL HAVE A DEEP TROUGH EXTENDING FROM THE GREAT LAKES...
THROUGH THE OHIO VALLEY...AND TO THE DEEP SOUTH. THIS TROUGH WILL
QUICKLY PULL EAST DURING THE DAY MONDAY ALLOWING HEIGHTS TO RISE
OVER EAST KENTUCKY INTO MONDAY NIGHT. MODERATE RIDGING WILL THEN
BUILD INTO THE STATE FROM THE WEST AND LATER NORTH FROM THE CENTRAL
GULF COAST. BY WEDNESDAY MORNING...THOUGH...SOME DISTINCT
DIFFERENCES START TO CROP UP AMONGST THE MODELS IN BOTH THE NORTHERN
AND SOUTHERN STREAMS. A WELL DEFINED MID LEVEL LOW RUNNING EAST
ALONG THE CANADIAN BORDER...IN THE GFS...IS REPRESENTED AS A
WEAKER...MORE PROGRESSIVE...OPEN WAVE IN THE 00Z ECMWF. THE LATEST
GEM APPEARS TO BE SIDING WITH THE GFS WITH THIS FEATURE. THE NET
RESULT FOR EAST KENTUCKY WILL BE SIMILAR REGARDLESS OF WHICH SOLUTION
PANS OUT AS THERE REMAINS GOOD AGREEMENT THAT RIDGING WILL BE IN
PLACE OVER OUR AREA THROUGH MIDWEEK. WHILE THE NORTHERN DETAILS WORK
THEMSELVES OUT...TO THE SOUTH A WEAKENING IMPULSE WILL MOVE THROUGH
THE SOUTHERN PLAINS LIKELY SERVING TO SUPPRESS THE LOCAL RIDGING AS
IT MOVES CLOSER TO THE CWA ON THURSDAY. IN FACT...BY 00Z FRIDAY THE
GFS IS SHOWING A FLAT TO SLIGHTLY TROUGHING PATTERN OVER EAST
KENTUCKY WHILE THE ECMWF STILL HAS THE BACK EDGE OF RIDGING HOLDING
ON THROUGH THE APPALACHIANS. DESPITE THE PATTERN DIFFERENCES...THE
HEIGHTS ARE RATHER SIMILAR OVER THE AREA INTO FRIDAY...ALONG WITH A
HEALTHY MIX OF ENERGY...KEEPING THINGS UNSETTLED. FOR SATURDAY...
WEAK RIDGING WILL REMAIN IN PLACE THROUGH THE AREA AS ANY IMPRESSIVE
WAVES STAY WELL NORTH OF THE AREA...MORE BEFITTING OF THIS TIME OF
YEAR. GIVEN THE SIMILARITY AND GENERAL CONSENSUS EXHIBITED BY THE
MODELS OVER EAST KENTUCKY THROUGH THE PERIOD...WILL FOLLOW A BLENDED
SOLUTION WITH LITTLE APPREHENSION...AND SOME CONFIDENCE THAT A MORE
NORMAL LATE SPRING WX PATTERN IS NEARLY UPON US.
AS FOR SENSIBLE WEATHER...MONDAY WILL START OUT CHILLY AND FROSTY
BUT MODERATE QUICKLY A HIGH PRESSURE MOVES INTO THE OHIO VALLEY. THE
WARMING WILL CONTINUE INTO TUESDAY AS A WARM FRONT PASSES TO THE
NORTH OF THE AREA. THIS WILL SET THE STAGE FOR A RARITY OF THIS
SPRING...A DAY OF ABOVE NORMAL TEMPERATURES...ON WEDNESDAY. ABOUT
THIS TIME A DEVELOPING FRONT SETS UP NORTH OF THE OHIO RIVER AND
INCREASING MOISTURE WILL BRING WITH IT BETTER CHANCES FOR CONVECTION
ON THURSDAY. THIS NEARBY FRONT...A MOIST BOUNDARY LAYER...AND WARM
TEMPERATURES WILL LIKELY KEEP...AT LEAST DIURNALLY DRIVEN...SHOWERS
AND THUNDERSTORMS AROUND THROUGH THE END OF THE WEEK AND INTO
SATURDAY. THE PRICE OF A MORE NORMAL SPRING PATTERN...AND A LACK OF
STRONG HIGH PRESSURE...DURING THE LATTER PART OF THE FORECAST WILL
BE A PATTERN MORE SIMILAR TO EARLY SUMMER MAKING AFTERNOON AND
EVENING CONVECTION A GOOD BET.
THE CR GRID LOAD CAME IN PRETTY GOOD...DID MAKE HOURLY ADJUSTMENTS
TO THE POPS AND SKY COVER TO BETTER HONE IN ON THE TIMES OF PEAK
CONVECTION FROM THURSDAY ON. ALSO...MADE SOME TERRAIN BASED
ADJUSTMENTS TO LOW TEMPERATURES EACH NIGHT FROM MONDAY THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 815 PM EDT SAT MAY 11 2013
DURING THE FIRST 3 TO 7 HOURS OF THE PERIOD...THE REGION WILL BE A
RELATIVE LULL IN CLOUDS BETWEEN THE DEPARTED COLD FRONT AND ANOTHER
APPROACHING COLD FRONT AND ASSOCIATED BAND OF CLOUDS AND SCATTERED
SHOWERS. DURING THE LULL AN IMPROVEMENT TO VFR SHOULD OCCUR IN ALL
BUT THE HIGHEST TERRAIN THE SOUTHEAST WHERE SKIES SHOULD IMPROVE TO
MVFR FROM IFR. A DROP DOWN TO MVFR OR PERHAPS LOWER IS ANTICIPATED
ALONG AND FOR ABOUT 3 HOURS BEHIND THE BOUNDARY. DRY AIR ADVECTION IN
LOWER LEVELS SHOULD LEAD TO IMPROVEMENTS BACK TO VFR AFTER THAT PERIOD.
WINDS WILL BE A BIT GUSTY FROM NW OR NNW...ESPECIALLY 15Z TO 22Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GEOGERIAN
LONG TERM...GREIF
AVIATION...JP
AREA FORECAST DISCUSSION...CORRECTED
NWS NEW ORLEANS LA
339 AM CDT FRI MAY 10 2013
.SHORT TERM...
QUITE ACTIVE MORNING IN STORE FOR ALL OF SOUTHEAST LOUISIANA AND
SOUTHERN MISSISSIPPI. A MCS THAT ORIGINATED IN NORTH CENTRAL TEXAS
HAS BECOME ORGANIZED AND IS CURRENTLY MARCHING ACROSS CENTRAL AND
SOUTHWEST LOUISIANA TOWARDS OUR CWA. STARTING UP TOP...DIFFLUENCE
ALOFT WILL AIDE IN THE COMPLEX MAINTAINING ITS INTENSITY AS IT
TRACKS EASTWARD. CAPE VALUES FOR OVERNIGHT PERIOD STILL QUITE
SUFFICIENT AT AROUND 1500 J/KG. MOISTURE IS NO ISSUE OF LIMITATION
EITHER AS LATEST SOUNDING SHOWED PLENTY THROUGHOUT THE COLUMN AND
SFC DEWPOINTS ARE WELL INTO THE 60S TO AROUND 70 AT THE COAST.
STEEP MID LEVEL LAPSE RATES WILL BE CONDUCIVE FOR SMALL HAIL AND
THUS VERY FREQUENT LIGHTNING. THIS ALONG WITH EMBEDDED VORTICIES
AND BOWING SEGMENTS CAN BE EXPECTED ALONG THIS LINE AS IT MOVES
THROUGH. SO ALL MODES OF SEVERE WEATHER POSSIBLE WITH DAMAGING
WINDS THE GREATEST THREAT THRU PRECIP LOADING. SEVERE THUNDERSTORM
WATCH NOW IN EFFECT UNTIL 10 AM FOR THIS THREAT. MEDIUM RANGE
MODELS PERFORMING FAIRLY POORLY WITH THIS MESO FEATURE.
GFS/ECMWF/SREF/NAM ALL SHOW IT MUCH FURTHER NORTH THAN IT ACTUALLY
IS. OF A FEW MESO MODELS...THE HRRR HAS INITIALIZED THE BEST AND
HAS BEEN DOING QUITE WELL OVER THE LAST FEW HOURS SO HAVE MOST
CONFIDENCE IN IT. THIS MODEL SHOWS THE LINE OF STORMS REMAINING
INTACT THROUGH MID MORNING(9-10AM). BY THIS TIME IT SHOULD BE
REACHING THE MISSISSIPPI COAST AND INTO THE NEW ORLEANS METRO
AREA. AS THE LINE PROGRESSES EASTWARD FROM THIS POINT...IT APPEARS
IT WILL BE MOVING INTO A LESS FAVORABLE ENVIRONMENT WITH MUCH LESS
INSTABILITY AND AND WEAKER MID LEVEL WINDS.
NOW...AFTER THIS FEATURE SWINGS THROUGH...THE REST OF THE AFTERNOON
WITH NOT BE TOO QUIET THOUGH SEVERE POTENTIAL LOOKS TO BE MUCH
LOWER. MESO MODELS SHOW A WIDESPREAD SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS THE CWA AFTER MAYBE A FEW HOURS OF DOWNTIME.
THINKING THAT THE MAIN THREAT WILL BE FLASH FLOODING. WITH AN INCH
OR 2 POSSIBLE WITH THIS MORNING/S MCS AND MORE IN THE AFTERNOON...
IT WILL NOT TAKE MUCH FOR STREETS TO FLOOD AS MUCH OF THE AREA HAS
BEEN GETTING POUNDED WITH RAIN FOR AWHILE NOW. NOT TO MENTION THAT
MODEL SOUNDINGS SHOW PRECIP WATER VALUES 1.5 TO 2 INCHES WHICH WILL
RESULT IN EFFICIENT RAIN PRODUCING THUNDERSTORMS. FLASH FLOOD WATCH
REMAINS IN EFFECT AND WARNINGS POSSIBLE THROUGHOUT THE DAY.
RELIEF DOESN/T COME UNTIL SOMETIME OVERNIGHT AND HOW MUCH DEPENDS ON
HOW LONG IT TAKES FOR NEXT IMPULSE TO REACH THE COAST. A VORTMAX
RUNNING NORTHEASTWARD ALONG THE SLOW MOVING FRONTAL BOUNDARY WILL
ENHANCE SHOWER AND THUNDERSTORM DEVELOPMENT ACROSS THE CWA FROM SW TO
NORTHEAST. THE POSITION OF THE FRONT IS FAIRLY CRITICAL TOO AS IT
WILL BE THE MAIN FOCUS FOR CONVECTION. GFS SUGGESTS IT WILL BE
FURTHER SOUTH ALONG THE LA COAST BY SAT 18Z. ECMWF AND SREF SAY
50-100 MILES FURTHER NORTH. FOR NOW THE FORECAST IS BASED ON THE
NORTHERN POSITION SO HAVE A HIGHER POP FORECAST THAT MAV/MEX. HEAVY
RAIN/TRAINING WILL CONTINUE WHEREVER MOST OF THE RAIN FALLS.
RAIN CHANCES WILL SIGNIFICANTLY FALL OFF SATURDAY NIGHT AND SUNDAY
AS SECONDARY FRONT FROM DEEPER UPPER LEVEL TROUGH SWINGS THROUGH.
HAVE TRIMMED POPS OFF ALL AREAS NORTH OF NEW ORLEANS METRO LATITUDE
BY SUNDAY. SLIGHTLY BELOW NORMAL TEMPS CAN BE EXPECTED THOUGH NOT BY
MUCH AS COMBINATION OF CLEAR SKIES AND HIGH ENOUGH SUN ANGLE WILL
KEEP HIGHS AROUND 80S.
MEFFER
.LONG TERM...
FAIRLY BENIGN WEATHER EXPECTED FOR MUCH OF NEXT WEEK. DEEP UPPER
TROUGH WILL BE MOVING ACROSS THE EASTERN CONUS ON MONDAY AND THEN
EXITING INTO THE ATLANTIC ON TUESDAY. BY THEN...STRONG UPPER RIDGING
WILL BE BUILDING INTO THE GULF COAST REGION. SO EXPECT THOSE TEMPS
TO QUICKLY RESPOND AND BOUNCE RIGHT BACK TO CLIMATOLOGICAL NORMALS.
RAIN CHANCES NIL TO LOW ALL WEEK.
MEFFER
&&
.MARINE...HIGH PRESSURE IS SLIDING EAST AND THIS IS TIGHTENING THE
PRESSURE GRADIENT OVER THE REGION. WINDS OF 15 TO 20 KTS ARE
OCCURRING OVER MUCH OF THE OPEN WATERS ALREADY AND WILL CONTINUE
THROUGH MUCH OF THE DAY UNTIL THE FRONT LAYS UP OVER THE CWA THIS
AFTN. THIS WILL LEAD TO A WEAKENING OF THE GRADIENT AND THUS WINDS
WILL BACK OFF. THE FRONT WILL SLOWLY SINK SOUTH TONIGHT AND THROUGH
THE WEEKEND AND FINALLY PUSH INTO THE GULF SUN NIGHT. HIGH PRESSURE
WILL QUICKLY BUILD IN BEHIND THE FRONT WITH MODERATE TO STRONG
OFFSHORE WINDS DEVELOPING OVER MOST OF THE OPEN WATERS SUN NIGHT.
HIGH PRESSURE WILL SLOWLY TAKE CONTROL OF THE SERN CONUS WITH WINDS
SLACKING OFF MON NIGHT AND TUE BUT BY TUE NIGHT AND INTO THE MIDDLE
OF NEXT WEEK MODERATE ONSHORE WILL REDEVELOP AS THE SFC HIGH PUSHES
OFF THE FL/GA COAST INTO THE WRN ATLANTIC. /CAB/
&&
.AVIATION...MOST TERMINALS ARE MAINLY DEALING WITH MVFR CIGS BUT
CONDITIONS WILL DETERIORATE THROUGH THE MORNING HAS A LINE OF SHRA
AND TSRA MOVES THROUGH THE AREA. BTR AND MCB WILL BE IMPACTED FIRST
AROUND 9-11Z FOLLOWED BY HDC/HUM/MSY/NEW/ASD B/T 12-14Z. CIGS AND
VISBIES WILL BOTH LOWER WITH THE CONVECTION AND GUSTS COULD APPROACH
40-50KTS WITH THE STRONGEST STORMS. THERE IS EVEN THE THREAT OF GR
BUT THE MAIN CONCERN IS WIND. EVEN AFTER THE MAIN LINE MOVES THROUGH
THERE WILL LIKELY BE SHRA AND EMBEDDED TSRA OVER THE REGION
THROUGHOUT THE DAY AND MAYBE EVEN INTO THE OVERNIGHT HRS. /CAB/
&&
.DECISION SUPPORT...
DSS CODE...YELLOW.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...SLURRY SUPPORT
MONITORING RIVERS
SEVERE THUNDERSTORM WATCH IN EFFECT
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR
AND/OR DIRECT TROPICAL THREATS; EVENTS OF NATIONAL
SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 80 65 78 57 / 100 60 70 10
BTR 82 68 80 61 / 100 60 70 20
ASD 79 68 80 61 / 100 50 80 20
MSY 81 70 80 64 / 90 40 80 20
GPT 78 69 78 62 / 90 50 80 20
PQL 78 69 80 60 / 70 40 80 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 1 AM SUNDAY FOR THE
FOLLOWING ZONES: ASCENSION...ASSUMPTION...EAST BATON
ROUGE...EAST FELICIANA...IBERVILLE...LIVINGSTON...NORTHERN
TANGIPAHOA...ORLEANS...POINTE COUPEE...SOUTHERN
TANGIPAHOA...ST. CHARLES...ST. HELENA...ST. JAMES...ST.
JOHN THE BAPTIST...ST. TAMMANY...UPPER JEFFERSON...UPPER
LAFOURCHE...UPPER PLAQUEMINES...UPPER ST. BERNARD...UPPER
TERREBONNE...WASHINGTON...WEST BATON ROUGE...AND WEST
FELICIANA.
GM...NONE.
MS...FLASH FLOOD WATCH FROM 7 AM FRIDAY TO 1 AM SUNDAY FOR THE
FOLLOWING ZONES:
AMITE...HANCOCK...HARRISON...JACKSON...PEARL
RIVER...PIKE...WALTHALL...AND WILKINSON.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
935 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH LATER TONIGHT AND CROSS THE REGION ON
SUNDAY WITH ADDITIONAL AFTERNOON SHOWERS. COLDER AND DRIER AIR WILL
FOLLOW FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
0930 UPDATE: THE TREND CONTINUES TO BE FOR A SLOWER EASTWARD
PROGRESSION OF SHOWERS ACROSS THE AREA SO BEEFED UP POPS AND QPF
FOR THE EVENING AND OVERNIGHT PERIOD BY UTILIZING A BLEND WITH RFC
QPF FOR THE EVENING AND THE SREF FOR THE OVERNIGHT PERIOD. AREAS
FROM AROUND BANGOR TO HOULTON SOUTH AND EASTWARD LOOK TO
POTENTIALLY SEE ANOTHER QUARTER TO HALF INCH OF RAIN THROUGH THE
EVENING AND OVERNIGHT PERIOD WITH THE HEAVIEST AMOUNTS OCCURRING
OVER WASHINGTON COUNTY. ALSO MADE SOME MINOR ADJUSTMENTS TO HOURLY
TEMPERATURES AND DEW POINTS FOR THE MID TO LATE EVENING BASED ON
CURRENT OBSERVATIONS.
0630 PM UPDATE: BEEFED UP POPS TO CATEGORICAL REGION WIDE FOR
EARLY THIS EVENING AS ADDITIONAL SHOWERS ARE MOVING IN AT THIS
HOUR. ALSO MADE SOME ADJUSTMENTS TO QPF FOR THIS
EVENING..GENERALLY UPPING AMOUNTS SLIGHTLY ACROSS MOST OF THE
AREA. FINALLY, SOME MINOR CHANGES TO WINDS AND TEMPERATURES FOR
THE EARLY TO MID EVENING PERIOD. NUDGED BOTH TEMPERATURES AND WINDS DOWN
SLIGHTLY BASED ON CURRENT OBSERVATIONS.
PREVIOUS DISCUSSION: MAIN CHALLENGES WILL BE TIMING OF RAIN
TONIGHT INTO SUNDAY AND TEMPERATURES.
FIRST AREA OF RAIN MOVING TO THE E INTO NEW BRUNSWICK WHILE SEND
AREA OF RAIN AND POSSIBLE TSTMS MOVING INTO SWRN AREAS ATTM PER
THE LATEST RADAR. THIS SECOND AREA OF RAIN WILL OVERSPREAD THE CWA
LATER THIS AFTERNOON INTO EARLY TONIGHT. 12Z UA INDICATED A STRONG
40KT JETLET AT 700MBS ACROSS ONTARIO AND WRN NYS. THIS AREA OF
FORCING WAS PICKED UP BY THE GFS AND CANADIAN GEM. THEREFORE, A
BLEND OF THESE 2 MODELS WERE USED INTO EARLY TONIGHT AS THEY SHOW
A SIGNIFICANT AREA OF RAIN MOVING ACROSS THE REGION. ATMOSPHERE
LOOKS LIKE IT STABILIZES AFTER 22Z AND THEREFORE CUT BACK ON THE
MENTION OF TSTMS FOR OUR CWA. THE LATEST RAP FROM THE SPC MESO-
ANALYSIS PAGE INDICATED SOME POSSIBLE TSTMS EDGING INTO GYX/S WRN
ZONES THIS AFTERNOON AND THEN WEAKENING BY 22Z OR SO. A BLEND OF
THE NERFC/GFS AND SREF WAS USED FOR THE QPF WHICH SHOWED AN
ADDITIONAL 0.15-0.30 THROUGH 06Z AND THEN RAIN END AS THE BEST
FORCING EXITS INTO NEW BRUNSWICK. ADDED FOG FOR ALL THE CWA
OVERNIGHT W/THE MOST DENSE FOG FROM MLT REGION ON SOUTH.
TEMPERATURES WILL BE HELD UP TONIGHT AND FOLLOWED A BLEND OF THE
NAM12 AND REGIONAL GEM FOR TONIGHT`S LOWS SHOWING UPPER 40S OUT
WEST TO LOW TO MID 50S EASTERN AND CENTRAL AREAS.
FOR SUNDAY, DRY W/SOME FOG TO START AND THEN ANOTHER BATCH OF
SHOWERS EXPECTED BY MIDDAY DUE TO THE COLD FRONT APCHG FROM THE W.
STAYED W/A GEM/GFS BLEND FOR TIMING OF THE SHOWERS USING THE MID
LEVEL FORCING FOR THE QPF WHICH SHOWED ANOTHER .10-.20, MAINLY
NORTHERN AND CENTRAL AREAS. HELD BACK THE TEMPERATURES FROM PREVIOUS
THINKING AND LEANED W/LOWER 60S NORTH AND MID 60S CENTRAL AND
DOWNEAST AS CAA LOOKS TO TAKE HOLD IN THE AFTERNOON. TSTM
POTENTIAL LOOKS TO BE LESS LIKELY ESPECIALLY ACROSS THE DOWNEAST
AND COAST DUE TO THE ONSHORE FLOW. BEST CHANCES IF ANY WILL BE
ACROSS THE NORTHERN AND WESTERN AREAS DUE TO SOME ELEVATED
INSTABILITY. ATTM, KEPT ISOLATED THUNDER IN THERE FOR CONTINUITY.
MIDNIGHT CREW CAN ASSESS THIS FURTHER TONIGHT.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
THE FIRST PART OF THE PERIOD WILL BEGIN WITH SHOWERS ACROSS THE
NORTHERN AND CENTRAL PARTS OF THE REGION SUNDAY NIGHT. THESE
SHOWERS ARE DUE TO A BOUNDARY THAT WILL MOVE FROM WEST TO EAST.
THE BEST LIFT LOOKS TO BE ACROSS THE NORTH. ONCE THIS FRONTAL
BOUNDARY PUSHES THROUGH THE REGION TEMPERATURES WILL COOL OFF FOR
MONDAY WITH HIGHS IN THE 50S NORTH AND THE UPPER 50S TO LOWER 60S
SOUTH. AS THE UPPER LEVEL TROUGH MOVES EAST THE 12Z GFS IS TRYING
TO CLOSE THE TROUGH TO THE NORTH WHILE THE 12Z NAM/00Z ECMWF
CONTINUE TO DEVELOP THE CLOSED LOW AROUND THE BASE OF THE TROUGH.
RIGHT NOW WILL LEAN WITH THE SURFACE LOW DEVELOPS TRACKING MAINLY
EAST OF THE AREA LATE TUESDAY INTO TUESDAY NIGHT. MAIN AFFECT TO
THE FORECAST FOR THIS PERIOD WILL BE THE INCREASE IN CLOUDS
COVERAGE WITH HIGHEST COVERAGE SEEN ACROSS THE EASTERN AND
SOUTHEASTERN PARTS OF THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
BOTH MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT IN THE TUESDAY
NIGHT THROUGH THROUGH SUNDAY TIME FRAME. THE FORECAST FOR
WEDNESDAY CONTINUES TO BE DRY. MOISTURE INCREASES WEDNESDAY
NIGHT...AHEAD OF THE NEXT SYSTEM EXPECTED TO MOVE THROUGH THE
AREA...BRINGING A CHANCE OF RAIN MAINLY ON THURSDAY. AT THIS POINT
IT APPEARS WE MAY HAVE A BREAK BETWEEN SYSTEMS ON FRIDAY HOWEVER
LATE FRIDAY INTO SATURDAY SHOULD SEE RAIN CHANCES INCREASE ACROSS
THE REGION ONCE AGAIN. SEASONAL TEMPERATURES ARE EXPECTED THROUGH
THE PERIOD WITH SOME DAYS A LITTLE ABOVE NORMAL AND OTHERS WITH
READINGS A LITTLE BELOW.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: IFR INTO SUNDAY MORNING AND THEN CONDITIONS GO TO MVFR
ESPECIALLY NORTHERN TERMINALS.
SHORT TERM: MOST TAF SITES WILL STAY VFR THROUGH THE PERIOD
EXCEPT FOR SUNDAY NIGHT WITH HEAVIER SHOWERS THERE COULD BE
PERIODS OF MVFR OR IFR.
&&
.MARINE...
NEAR TERM: DECIDED TO TRANSITION THE SCA TO HAZARDOUS SEAS INTO
SUNDAY. WAVES ARE CLIMBING TO 6 ATTM W/A SWELL GENERATED. WILL
CARRY THE MENTION OF THE SWELL INTO SUNDAY. WINDS ARE BELOW SCA
AND EXPECTING THEM TO STAY BELOW INTO SUNDAY. FOLLOWED THE
NAM12/GFS40 BLEND FOR THE WINDS AND FOLLOWED CLOSELY W/THE
MIDNIGHT CREW`S WAVE HEIGHTS OF 4-7 FT.
SHORT TERM: SCA CONDITIONS SUBSIDE BY THE SHORT TERM PERIOD.
KEPT CONSISTENCY WITH LAST NIGHTS SHIFT FOR WAVE AND WIND GRIDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT SUNDAY
FOR ANZ050>052.
&&
$$
NEAR TERM...FITZSIMMONS/HEWITT
SHORT TERM...JORDAN
LONG TERM...RUNYAN
AVIATION...FITZSIMMONS/HEWITT/JORDAN
MARINE...FITZSIMMONS/HEWITT/JORDAN
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
852 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT CROSSES THE MID ATLANTIC TONIGHT FOLLOWED BY A
SECONDARY COLD FRONT SUNDAY EVENING. CANADIAN HIGH PRESSURE BUILDS
INTO THE REGION MONDAY AND MONDAY NIGHT BRINGING A VERY COOL
AIR FOR THE MIDDLE OF MAY...BEFORE SLIDING OFF THE COAST TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
THE LATEST REGIONAL RADAR MOSAIC SHOWS ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS ACROSS THE REGION MARGINALLY UNSTABLE AIRMASS
(~1000 J/KG OF MLCAPE) ALONG WITH MODEST DEEP LAYER SHEAR (30-40KT
0-6KM). CURRENT GOES WATER VAPOR IMAGERY SHOWS A SHORTWAVE TROUGH
LIFTING NE ACROSS PA ALONG WITH STRONGER SYNOPTIC SCALE
DYNAMICS...HENCE ANY STORMS ACROSS THE LOCAL AREA HAVE STRUGGLED TO
ORGANIZE AND PERSIST. THIS TREND IS EXPECTED TO CONTINUE OVER THE
NEXT FEW HOURS BEFORE A JET STREAK OVER THE TENNESSEE VALLEY EJECTS
NE ACROSS THE REGION AHEAD OF A FRONTAL ZONE APPROACHING FROM THE
WEST.
THE LATEST RUC BRINGS THE JET ACROSS THE AREA DURING THE MID-EVENING
THROUGH EARLY OVERNIGHT HOURS. GIVEN THIS...A BAND OF LIKELY POPS
WILL BE FORECAST TO MOVE W-E OVER THE CWA. HOWEVER...QPF AMOUNTS
SHOULD BE RATHER MINIMAL. THUNDER WILL BE MAINTAINED THROUGH
MIDNIGHT TO ACCOUNT FOR ANY LINGERING INSTABILITY BEFORE
TRANSITIONING TO ONLY SHOWERS AFTER MIDNIGHT. LOW TEMPERATURES SHOULD
RANGE FROM THE LOW 50S NW...TO LOW 60S SE.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/...
STEADY CAA COMMENCES SUNDAY AS THE COLD FRONT MOVES OFF THE COAST
SUNDAY MORNING AND HIGH PRESSURE BUILDS OVER THE MISSISSIPPI VALLEY.
THIS SHOULD PRODUCE A RATHER PLEASANT DAY WITH LOW-LEVEL THICKNESS
VALUES SUPPORTING HIGHS IN THE UPPER 60S N/NW...TO THE LOW/MID 70S
SE UNDER AN INCREASINGLY SUNNY SKY.
A SECONDARY COLD FRONT SWINGS THROUGH THE REGION SUNDAY NIGHT. THE
CONTINUATION OF STEADY CAA OVERNIGHT WILL DRIVE LOW TEMPERATURES
DOWN INTO THE UPPER 30S N/NW TO THE MID/UPPER 40S FAR SE UNDER A
CLEAR SKY. THERE SHOULD BE ENOUGH MIXING ALONG WITH DRY AIR/LOW
DEWPOINTS TO INHIBIT ANY FROST DEVELOPMENT IN THE COLDER SPOTS.
VERY COLD AIR ALOFT FOR MID-MAY ARRIVES MONDAY DRIVING 1000-500MB
THICKNESS VALUES DOWN TO AROUND 532-540DAM. A STRONG VORT MAX/PV MIN
DIVES AROUND THE BACK-SIDE OF THE PARENT TROUGH DURING THE
AFTERNOON. THIS ENERGY DROPPING INTO THE TROUGH WILL DROP 500MB
HEIGHTS TO -2 TO -3 ST DEV PER 11/12Z GEFS MEAN AT 00Z TUESDAY.
GIVEN THIS...A BKN SC DECK IS EXPECTED TO DEVELOP DURING THE
AFTERNOON. LOW AND MID LEVEL LAPSE RATES WILL BE RATHER STEEP...SO
THERE WILL BE A MINIMAL POTENTIAL OF SHOWERS WHEN COMBINED WITH THE
COLD AIR ALOFT AND MID/UPPER LEVEL ENERGY. HOWEVER...POPS WILL BE
LIMITED BELOW 15 PERCENT AT THIS TIME GIVEN THAT THE AIRMASS WILL BE
VERY DRY (SFC DEWPOINTS IN THE MID/UPPER 20S INLAND).
850MB TEMPERATURES DROP TO AROUND 0C MONDAY...WHICH IS AROUND -2 ST
DEV BELOW NORMAL PER 11/12Z GEFS MEAN. FULLY MIXED...AS EXPECTED
WILL RESULT IN HIGH TEMPERATURES RANGING FROM THE UPPER 50S N...TO
NEAR 65 FAR S...WHICH WOULD ALSO BE AROUND -2 ST DEV BELOW SEASONAL
MEANS. DAYTIME HIGHS MAY BE REACHED AROUND MIDDAY BEFORE DROPPING A
FEW DEGREES IN THE AFTERNOON AS CLOUD COVER INCREASES.
CANADIAN HIGH PRESSURE SETTLES OVER THE PIEDMONT MONDAY NIGHT INTO
TUESDAY MORNING. THE SKY SHOULD CLEAR MONDAY EVENING...WHICH WILL
EVENTUALLY RESULT IN A COOL START TO THE DAY TUESDAY. FORECAST LOWS
RANGE FROM THE MID 30S OVER THE PIEDMONT AND E/S-CENTRAL VA COASTAL
PLAIN TO THE LOW/MID 40S FOR SE COASTAL LOCATIONS. IF ANY FROST
POTENTIAL EXISTS...IT WOULD LIKELY BE OVER THE PIEDMONT WHERE FULL
DECOUPLING COULD OCCUR.
THE HIGH DRIFTS OFFSHORE TUESDAY. LIGHT ONSHORE FLOW WILL MAINTAIN
RATHER COOL HIGHS IN THE LOW 60S (STILL NEAR -1.5 ST DEV) NEAR THE
COAST...AND LIGHT RETURN FLOW SHOULD ALLOW HIGHS TO RISE INTO THE
UPPER 60S TO NEAR 70 OVER THE PIEDMONT UNDER A MOSTLY SUNNY SKY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
HI PRES WILL SLIDE INTO THE ATLC FOR TUE NGT THRU THU. A WARM
FRONT WILL SLOWLY LIFT THRU THE REGION AND OFFSHR LATE TUE NGT
THRU THU MORNG. AT THIS TIME...WILL MAINTAIN A DRY FCST DURING
THIS PERIOD...BUT ANY ISLTD PCPN WILL LIKELY OCCUR ACRS THE NRN
THIRD OF THE AREA. SLGT CHC FOR SHOWERS OR TSTMS...MAINLY ACRS THE
NRN HALF OF THE REGION THU AFTN INTO FRI MORNG...AS A WEAK TROF
MOVES THRU THE AREA. GOING WITH SLGT CHC FOR SHOWERS AND TSTMS
(OCCURRING MAINLY AFTN/EVENG HRS) FRI THRU SAT...IN RELATIVELY
WARM AND MARGINALLY UNSTABLE AIRMASS IN ADVANCE OF MAIN COLD FRONT
N OF THE REGION. MIN TEMPS WILL RANGE FM THE MID 40S TO LWR 50S
WED MORNG...AND MAINLY IN THE MID 50S TO LWR 60S THU...FRI...AND
SAT MORNGS. MAX TEMPS WILL RANGE THRU THE 70S WED...AND GENERALLY
IN THE UPR 70S TO MID 80S THU...FRI AND SAT.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
A COLD FRONT IN THE MIDWEST WILL MOVE E/SE DURING THE TAF PERIOD
APPROACHING FROM THE W/NW AND MOVING THROUGH SATURDAY NIGHT AND
EARLY SUNDAY MORNING. PCPN CHANCES SLOWLY INCREASE DURING THE
PERIOD. AN AREA OF SHOWERS AND A FEW TSTMS IN THE MOUNTAINS TO THE
WEST AND IS EXPECTED TO DIMINISH TO WIDELY SCT SHOWERS OVERNIGHT.
THERE WILL BE A LOW CHANCE FOR SHOWERS AT THE TAF SITES MAINLY
RIC/SBY AFT 06Z THROUGH 18Z. THE CHANCES INCREASE AFT 18Z BUT ONLY
MENTIONED AT SBY WHERE BOTH NAM AND GFS MOS ARE QUITE BULLISH ON
PCPN. OTHERWISE...DID NOT WANT TO PUT SIX HOURS OF PCPN IN THE FCST
FOR SHOWERS/TSTMS THAT WILL LIKELY LAST FOR ONLY A COUPLE OF HOURS.
PCPN MAY BE MORE PERSISTENT AFT 00Z. LATER ISSUANCES WILL BE BETTER
ABLE TO PIN DOWN TIMING OF ANY CONVECTION.
NO SIGNIFICANT IFR IS INDICATED IN THE LONG TERM. PCPN ENDS FROM THE
WEST SATURDAY NIGHT. AN EXTENDED OF DRY WEATHER IS EXPECTED EARLY
NEXT WEEK.
&&
.MARINE...
NO HEADLINES IN THE SHRT TERM TNGT THRU MON. SSW WINDS 10 TO 20 KT
THIS EVENG...WILL BECOME W OR NW 10 TO 15 KT BY SUN MORNG AS THE
COLD FRONT MOVES TO JUST OFFSHR. NW OR N WINDS ARND 15 KT OR LESS
SUN MORNG INTO SUN AFTN...DUE TO MINOR SURGE BEHIND EXITING COLD
FRONT. ANOTHER NNW SURGE (SUB-SCA) EXPECTED SUN NGT INTO MON
MORNG...AS HI PRES BLDS TWD THE AREA FM THE W. THE HI WILL BLD
RIGHT OVR THE REGION LATE MON NGT THRU TUE...THEN SLIDES INTO THE
ATLC FOR TUE NGT INTO THU.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...AJZ
NEAR TERM...AJZ
SHORT TERM...AJZ
LONG TERM...TMG
AVIATION...LSA
MARINE...TMG
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
711 PM EDT SAT MAY 11 2013
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 447 PM EDT SAT MAY 11 2013
WV IMAGERY AND RUC ANALYSIS INDICATED AN AMPLIFIED MID/UPPER LEVEL
PATTERN WITH A TROUGH FROM HUDSON BAY INTO THE WESTERN GREAT LAKES.
THE MID LEVEL LOW CENTER HAD DROPPED TO NEAR CYQT AS THE SHORTWAVE
TROUGH THAT SUPPORTED THE MORNING PCPN BAND SHIFTED INTO ERN UPPER
MI AND LAKE SUPERIOR. RADARS INDICATED THAT SCT -SHSN SUPPORTED BY
DIURNAL HEATING AND INFLUX OF COLDER AIR AND WRAP-AROUND MOISTURE
WERE SPREADING FROM NE MN AND WRN LAKE SUPERIOR INTO WRN UPPER MI.
UPSTREAM...THE 12Z CYPL SOUNDING INDICATED PLENTIFUL MOISTURE TO
INVERSION AROUND 12K FT(650)MB.
TONIGHT...MAINLY LIGHT SNOW SHOWERS ARE EXPECTED LATE THIS AFTERNOON
AND EVENING ACROSS THE WEST. HIGHER RES MODELS SUGGEST SHSN WILL
EXPAND IN COVERAGE AND INTENSITY ACROSS THE WEST FROM 00Z-03Z AND
INTO THE ERN CWA MAINLY AFT 03Z. WITH VERY FAVORABLE CONDITIONS FOR
LAKE ENHANCED SNOW DEVELOPING...SEVERAL INCHES OF SNOW WILL BE
POSSIBLE OVERNIGHT.
WITH CAA INCREASING AND WINDS VEERING AS A SECONDARY SHRTWV MOVES
THROUGH...TEMPS AT 850 MB FALL TO AROUND -8C WITH INVERSION TOP
TEMPS TO NEAR -18C...PER NAM. ALTHOUGH LAKE INDUCED CAPES ARE
RELATIVELY MODEST...MOISTURE THROUGH 650 MB AND SHARP CYCLONIC
LOW-LEVEL FLOW WILL BOOST CONVERGENCE AND ALLOW FOR AT A PERIOD OF
HEAVIER LAKE ENHANCED SNOW DOWNWIND OF LONGER FETCH OVER CNTRL AND
ERN LAKE SUPERIOR. SNOW ACCUMULATIONS IN THE 1 TO 4 INCH RANGE ARE
POSSIBLE WITH THE GREATEST AMOUNTS IN THE HIGHER TERRAIN FROM THE
HURON MOUNTAINS TO NEGAUNEE AND FROM ALGER COUNTY THROUGH NRN
SCHOOLCRAFT AND NRN LUCE COUNTY.
IN ADDITION TO THE SNOW...VERY STRONG WINDS ARE EXPECTED AFT 03Z AS
A PRES RISE MOVES THROUGH AND THE GRADIENT TIGHTENS WITH THE SFC LOW
DEEPENING E OF LAKE SUPERIOR. MIXED LAYER WINDS TO 40-45 KNOTS SUGGEST
POTENTIAL FOR WIND GUSTS TO AROUND 45 MPH IN EXPOSED LOCATIONS NEAR
THE LAKE SUPERIOR SHORELINE FROM MARQUETTE EASTWARD. A WINTER WEATHER
ADVISORY WAS ISSUED FOR THE COMBINATION OF WINDS AND SNOW.
SUN...WITH LINGERING DEEP CYCLONIC NNW FLOW AND AROUND -10C 8H
TEMPS MOVING ACROSS LAKE SUPERIOR IN THERMAL TROUGH...EXPECT SOME
LINGERING RAIN/SNOW SHOWERS EARLY IN THE MORNING OVER THE EAST WHERE
LONGER FETCH WILL BE MORE FAVORABLE FOR LAKE EFFECT EFFECT PCPN.
OTHERWISE...SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD BRING AND END
TO ANY LINGERING BY MID AFTERNOON. FAIRLY TIGHT NW PRES GRAD ON THE
BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR 35 MPH OVER
THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 447 PM EDT SAT MAY 11 2013
RELATIVELY COLD HIGH TEMPS ARE EXPECTED FOR SUN...SO GOING INTO SUN
NIGHT WITH SFC RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE
W...SHOULD SEE SFC TEMPS FALL SHARPLY /ESPECIALLY OVER THE WRN
CWA/...EVEN THOUGH TEMPS ALOFT WARM SUN NIGHT. EXPECT LOWS SUN NIGHT
AROUND 20F /EVEN IN THE MID-UPPER TEENS IN COLDER SPOTS/ OVER
PORTIONS OF INTERIOR W UPPER MI...WITH LOWS AROUND OF BELOW FREEZING
IN MOST LOCATIONS. LOWERED TEMPS A FEW DEGREES IN COLDER SPOTS GIVEN
GUIDANCE COMING IN WITH COLDER TEMPS...BUT DID NOT GO AS LOW AS
COLDEST GUIDANCE.
SHOULD SEE 850MB TEMPS BETWEEN 18Z SUN AND 00Z TUE INCREASE BY 5C
OVER THE ERN CWA AND 12C OVER THE WRN CWA. THEREFORE...WILL SEE
WARMER TEMPS FOR MON THAN SUN...ESPECIALLY OVER THE WRN CWA. HIGH
TEMPS FOR MON ARE EXPECTED TO BE AROUND 60 OVER THE INTERIOR WRN CWA
AND AROUND 50 OVER THE FAR ERN CWA. COULD SEE SOME WAA PRECIP MOVING
ACROSS THE CWA LATE MON INTO MON NIGHT...BUT MOISTURE AND FORCING DO
NOT LOOK THAT IMPRESSIVE SO WILL KEEP POPS ON THE LOW END MON INTO
MON NIGHT.
MODELS HINT AT PRECIP FOR TUE ALONG A WARM FRONT AHEAD OF A
SHORTWAVE AND SFC LOW THAT MOVE INTO SRN MANITOBA BY 00Z WED.
AGAIN...MOISTURE AND FORCING WILL BE LIMITED SO WILL KEEP POPS LOW.
THUNDERSTORMS WILL BE POSSIBLE WITH THE PRECIP GIVEN ELEVATED
INSTABILITY AND DECENT LAPSE RATES. 850MB TEMPS INCREASE ANOTHER 13C
OVER THE WRN CWA TO 16C BETWEEN 00Z TUE AND 00Z WED...AND INCREASE
ANOTHER 10C TO 9C OVER THE FAR ERN CWA. SHOULD BE ABLE TO GET HIGHS
AROUND 70 OVER THE INTERIOR WRN CWA AND AROUND 60 OVER THE ERN CWA.
THE SFC LOW AND SHORTWAVE MOVE N OF THE CWA TUE NIGHT INTO
WED...WITH MODEL DISCREPANCIES ON TIMING OF THE SYSTEM. THIS BRINGS
A COLD FRONT ACROSS THE CWA BY AT LEAST 18Z WED /SLOWER GFS
TIMING/...WHICH WILL TURN WINDS OUT OF THE WNW AND COOL TEMPS A BIT.
SHOWERS AND THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE. MOISTURE
WILL BE MORE LIMITED ALONG THE SRN CWA...SO WILL KEEP POPS LOWER
THERE. WILL GO WITH LIKELY POPS OVER THE NRN/ERN CWA WHERE MOISTURE
AND FORCING WILL BE BETTER. EVEN WITH COOLER OVERHEAD
AIRMASS...AFTER THE FRONT PASSES WED MORNING...SKIES WILL CLEAR
OUT...ALLOWING SFC TEMPS TO WARM UP HIGHER THAN THE CLOUDIER TUE
AWAY FROM LAKE SUPERIOR. HIGHS LOOK TO BE IN THE MID 70S OVER THE
SCENTRAL CWA WED...AND AROUND 70S ELSEWHERE OVER THE INTERIOR CWA.
THU THROUGH NEXT SAT...CONFIDENCE IS LOWERED BY LACK OF MODEL
AGREEMENT AND RUN TO RUN DISCONTINUITY. WILL JUST RUN WITH WHATEVER
CONSENSUS OF MODELS COMES UP WITH FOR THIS TIME PERIOD.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 711 PM EDT SAT MAY 11 2013
VFR CIGS AT IWD AND SAW WILL COME DOWN TO MVFR TONIGHT WITH DIURNAL
COOLING. SOME LAKE ENHANCEMENT SNOW SHOWERS WILL CONTINUE AT CMX AND
WILL MOVE INTO SAW TONIGHT WITH IFR VISIBILITY IN THE HEAVIER SNOW
SHOWERS. DRY AIR COMES IN LATE SUN MORNING AND IWD AND CMX WILL GO
BACK TO VFR CONDITIONS. IT WILL TAKE A BIT LONGER TO GET THE DRY AIR
INTO SAW AND THE MVFR CIGS WILL SCATTER OUT BY SUN AFTERNOON. WILL
BE GUSTY THROUGH SUN AFTERNOON AT ALL SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 447 PM EDT SAT MAY 11 2013
EXPECT A STRONG GALE TO DEVELOP OVER MOST OF THE LAKE BY LATE THIS
EVENING AND LASTING INTO AT LEAST SUN MORNING BEFORE DIMINISHING. A
GALE WARNING REMAINS IN EFFECT FOR MUCH OF LK SUPERIOR FOR WINDS
40-45 KTS. RIDGING MOVES OVER LAKE SUPERIOR SUN NIGHT AND
MON...LEADING TO RELATIVELY CALM WINDS. WINDS WILL INCREASE OUT OF
THE S MON NIGHT THROUGH TUE NIGHT AHEAD OF A LOW PRESSURE SYSTEM
THAT WILL MOVE N OF LAKE SUPERIOR WED...BRINGING A SOUTHWEST SHIFT
TO THE WINDS WED.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY FROM 11 PM THIS EVENING TO 8 AM EDT
SUNDAY FOR MIZ006-007-085.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT SUNDAY FOR MIZ005.
LAKE SUPERIOR...
GALE WARNING FROM MIDNIGHT TONIGHT TO 6 PM EDT SUNDAY FOR LSZ251-
267.
GALE WARNING UNTIL 6 PM EDT SUNDAY FOR LSZ249-250-266.
GALE WARNING UNTIL 2 PM EDT SUNDAY FOR LSZ243>245-264-265.
GALE WARNING UNTIL 8 AM EDT SUNDAY FOR LSZ248.
GALE WARNING UNTIL 8 AM EDT SUNDAY FOR LSZ263.
LAKE MICHIGAN...
GALE WARNING FROM MIDNIGHT TONIGHT TO 8 AM EDT SUNDAY FOR LMZ250.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
340 PM CDT FRI MAY 10 2013
.SHORT TERM...(TONIGHT THROUGH SATURDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE FIRST SHOT OF COOLER AIR HAS OVERSPREAD THE AREA WITH THE
ASSOCIATED COLD FRONT NOW ACROSS EXTREME SOUTHEAST MISSOURI AND
SOUTHERN ILLINOIS. EXTENSIVE STRATUS BLANKETS MUCH OF THE AREA AND
EXTENDS WELL NORTH INTO EASTERN IOWA AT MID AFTERNOON. THE MODELS
VARY ON HOW QUICKLY TO CLEAR THE LOW CLOUDS...AND I HAVE SIDED
WITH THE SLOWER RUC AND LOCAL WRF WITH SLOW CLEARING FROM NORTH TO
SOUTH TONIGHT...AND THE SOUTHEAST CWA NOT CLEARING UNTIL AFTER
DAYBREAK ON SATURDAY. A SERIES OF POWERFUL SHORT WAVES NOW ACROSS
MANITOBA AND SASKATCHEWAN WILL DIG SOUTHEASTWARD TONIGHT WITH A
CLOSED LOW EVOLVING. THIS UPPER LOW/TROF WILL CONTINUE TO DEEPEN
WITH A BROAD DEEP LONGWAVE TROF EVOLVING ACROSS THE EASTERN CONUS
BY SATURDAY NIGHT. INTIALLY IN THE PROCESS...THE DIGGING TROF
WILL DRIVE A COLD FRONT ACROSS THE AREA ON SATURDAY. THIS FRONT
WILL USHER A MORE POTENT BLAST OF CHILLY AIR INTO THE REGION ON
THE ORDER OF 2-3 STANDARD DEVIATIONS BELOW NORMAL. IT STILL LOOKS
LIKE THERE WILL BE A CHANCE OF SHOWERS AND EVEN SOME THUNDERSTORMS
FORMING ALONG THE FRONT AS IT MOVES QUICKLY SOUTHEASTWARD. THE
FORCING APPEARS TO BE LARGELY FRONTAL AND THIS SUGGESTS SCATTERED
COVERAGE. INSTABILITY WILL BE WEAK...PROBABLY OVERDONE ON THE NAM
OWING TO TOO HIGH SURFACE DEW POINTS...BUT STILL GREAT ENOUGH TO
SUPPORT A THUNDER THREAT. IT WILL BE A NARROW 1-2 HOUR WINDOW FOR
PRECIPITATION OCCURING WITH THE FRONT AND THEN GUSTY NW WINDS IT
ITS WAKE.
GLASS
.LONG TERM...(SATURDAY NIGHT THROUGH NEXT FRIDAY)
ISSUED AT 328 PM CDT FRI MAY 10 2013
THE DEEP LONGWAVE TROF WILL DOMINATE THE PATTERN AND CONTROL THE
SENSIBLE WEATHER SATURDAY NIGHT INTO EARLY MONDAY WITH A COOL
SURFACE HIGH PREVAILING. BELOW AVERAGE TEMPERATURES WILL BE THE
RULE AND SOME RECORDS COULD BE APPROACHED ON SUNDAY MORNING. THERE
COULD ALSO BE SOME PATCHY FROST WHERE LOWS DIP INTO THE MID 30S.
THE SURFACE HIGH MOVE ACROSS THE AREA ON SUNDAY AND GRADUALLY
RETREAT SOUTHEAST SUNDAY NIGHT INTO THE WESTERN TN VALLEY. THIS
SUGGESTS THAT THE COOLEST TEMPERATURES ON SUNDAY NIGHT AND MONDAY
MORNING WILL BE ACROSS THE EASTERN OZARKS AND SW ILLINOIS WHERE
LOWS IN THE MID-UPPER 30S AND PATCHY FROST WILL ONCE AGAIN BE
POSSIBLE. LOW LEVEL WAA WILL THEN COMMENCE ON MONDAY AND THIS
SHOULD LEAD TO A NICE REBOUND IN TEMPERATURES AS THE LOWER
TROPOSPHERIC FLOW BECOMES MORE SOUTHERLY.
SAY GOODBYE TO THE COOL...I THINK FOR GOOD...BY TUESDAY. THE LONGWAVE
TROF DEPARTS OFF THE EAST COAST AND HEIGHTS RISE ALOFT AS A SHORT
WAVE RIDGE BUILDS INTO THE MS VALLEY. STRONG WAA WILL PROGRESS AND
H85 TEMPS ARE FORECAST TO RISE ABOVE +18 DEGC ON ALL THE GUIDANCE...
SUPPORTING HIGHS WELL INTO THE 80S. MOISTURE AND CLOUDS WILL BEGIN
TO INCREASE LATE WEDNESDAY AS A NEW UPSTREAM TROF MOVES ACROSS THE
PLAINS AND EVENTUALLY INTO THE MS VALLEY BY THURSDAY. THE MODELS
DISAGREE ON WHETHER AN EAST-WEST FRONT WILL ALSO DROP INTO THE
AREA DURING THIS TIME...BUT THE PRESENCE OF THE UPPER TROF ALONE
SUPPORTS A CHANCE OF SHOWERS AND THUNDERSTORMS DURING THE LATER
PART OF THE WEEK.
GLASS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1200 PM CDT FRI MAY 10 2013
LARGE AREA OF POST FRONTAL MVFR CIGS WILL LAST WELL INTO THE
EVENING OVER TAF SITES...THEN SLOWLY LIFT AND SCATTER OUT DURING
THE OVERNIGHT PERIOD. NW WINDS WILL DIMINISH BY AROUND
MIDNIGHT...THEN BECOME LIGHT AND VARIABLE BY DAYBREAK ON SATURDAY.
A SECONDARY COLD FRONT WILL MOVE THROUGH THE AREA FROM MID MORNING
NEAR KUIN...TO AROUND NOON AT KSTL. AN AREA OF CIGS NEAR 030 WILL
ACCOMPANY THIS FRONT...WITH A SMALL CHANCE FOR SHOWERS AS
REFLECTED IN THE VCSH. NW WINDS WILL AGAIN INCREASE BEHIND THIS
FRONT AND BECOME GUSTY.
SPECIFICS FOR KSTL...
MVFR CIGS WILL SLOWLY LIFT THEN SCATTER OUT BY 0900Z. NW WINDS
WILL DIMINISH SHORTLY AFTER SUNSET...THEN BECOME LIGHT AND
VARIABLE BY DAWN ON SATURDAY. SECONDARY COLD FRONT WILL MOVE
THROUGH TAF SITE AROUND NOON...BRINGING WIDELY SCATTERED SHOWERS
AND INCREASING NW WINDS.
WEBBER/BROWNING
&&
.CLIMATE...
ISSUED AT 328 PM CDT FRI MAY 10 2013
RECORD LOWS
5/125/13
ST LOUIS39 (1960)40 (1971)
COLUMBIA35 (1892)34 (1901)
QUINCY35 (1960)35 (1971)
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1256 AM CDT FRI MAY 10 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
A FEW LIGHT SHOWERS WILL CONTINUE TO WRAP AROUND THE
SURFACE LOW ACROSS THE MIDDLE MISSISSIPPI RIVER VALLEY THROUGH THE
LATE AFTERNOON HOURS...AS IT CONTINUES TO TRANSITION FURTHER
EASTWARD. STILL CANNOT RULE OUT THE SLIGHT POSSIBILITY OF A
THUNDERSTORM OR TWO...MAINLY ACROSS PORTIONS OF NORTH CENTRAL
KANSAS...AS MESO ANALYSIS PAGE FROM SPC IS INDICATION SOME WEAK
INSTABILITY PERSISTING ACROSS THIS AREA. LATEST WRF ACTUALLY
HANGS ONTO SOME SCATTERED SHOWER ACTIVITY THROUGH THE OVERNIGHT
HOURS...BUT THIS MODEL SEEMS TO BE THE OUTLIER...SO HAVE NO MORE
THAN A FEW SPRINKLES IN THE FORECAST AFTER 00Z.
THEREAFTER...EXPECT A SURFACE RIDGE OF HIGH PRESSURE TO SLIDE
ACROSS THE FORECAST AREA FROM THE WEST OVERNIGHT...AND WITH THE
ANTICIPATED LIGHT WINDS...PARTIAL CLEARING...AND ELEVATED DEW
POINTS...EXPECT SOME FOG DEVELOPMENT OVERNIGHT. LATEST HRRR IS
HINTING AT DENSE FOG FORMING ALONG THE SPINE OF THE RIDGE AXIS
AFTER MIDNIGHT...BUT WITH SOME UNCERTAINTY STILL...ONLY REDUCED
VISIBILITIES TO 1 MILE ACROSS THE FORECAST AREA DURING THE LATE
OVERNIGHT HOURS THROUGH EARLY FRIDAY MORNING...AND HELD OFF ON
ISSUING A DENSE FOG ADVISORY FOR THE TIME BEING.
AFTER THE FOG BURNS OFF FRIDAY MORNING...EXPECT A FAIRLY NICE AND
SEASONAL DAY ACROSS THE REGION...AS THE SURFACE RIDGE WILL BE SLOW
TO PUSH EAST RESULTING IN GENERALLY LIGHT WINDS DURING THE
AFTERNOON HOURS. WITH CLEARING SKIES...RECOVERING TEMPERATURES
ALOFT...AND GOOD MIXING ANTICIPATED...EXPECT TEMPERATURES TO
RETURN TO NEAR CLIMATOLOGICAL NORMS...GENERALLY IN THE LOWER 70S
AT MOST LOCATIONS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM CDT THU MAY 9 2013
REALLY NO SIGNIFICANT CHANGES FOR THE FIRST PORTION OF THE LONG TERM
PERIOD...FRIDAY NIGHT THROUGH THE DAY SATURDAY. MODELS REMAIN IN
PRETTY GOOD AGREEMENT WITH THE OVERALL PATTERN...SHOWING FRIDAY
EVENING UNDER SHARP NORTHWESTERLY FLOW...A RESULT OF A TROUGH AXIS
PUSHING EAST OF THE CWA...AND RIDGING POKING INTO THE CENTRAL/NRN
WEST COAST...NORTH OF CUT OFF LOW OVER THE NM/AZ/MEX BORDER AREA.
FOCUS TURNS TO AN UPPER LEVEL LOW PRESSURE SYSTEM OVER CENTRAL
CANADA...WHICH IS EXPECTED TO SLIDE SOUTHEAST OVERNIGHT AND BY
SATURDAY MORNING IS REACHING INTO THE WRN GREAT LAKES AREA. THE
ACCOMPANYING TROUGH AXIS WILL EXTEND TO THE SOUTH AND SWING THROUGH
THE CENTRAL PLAINS PRIMARILY FRIDAY NIGHT...AND KEPT THE MENTION OF
SPRINKLES GOING ACROSS THE NRN HALF OF THE CWA. WITH THE BRUNT OF
THE LIFT WELL NE OF THE CWA...AND FORECAST SOUNDINGS CONTINUING TO
SHOW DRIER AIR IN THE AREA...DIDNT WANT TO INSERT ANY MEASURABLE
PRECIP AT THIS POINT. THE TIMING OF THE SFC COLD FRONT PUSHED
THROUGH THE CWA BY THIS DISTURBANCE HASNT CHANGED MUCH WITH THE
LATEST MODEL RUNS...AND BY 12Z SATURDAY LOOKS TO HAVE PUSHED THROUGH
TO AT LEAST THE NE/KS STATE LINE...AND EVEN A LITTLE FURTHER SOUTH
VIA THE NAM/SREF. THROUGH THE DAYTIME HOURS ON SATURDAY...SHOULD
SEE DECREASING CLOUD COVER...AND EXPECTING WINDS TO BE ON THE GUSTY
SIDE THROUGH AT LEAST THE FIRST HALF OF THE DAY...BUT SHOULD
DIMINISH ESP BY LATE AFTERNOON AS SFC HIGH PRESSURE BUILDS IN FROM
THE NORTH. THE COOLER AIRMASS ACCOMPANYING THIS FRONT IS EXPECTED
TO BRING A DROP IN HIGHS...BUT STILL EXPECTING TO REACH INTO THE
60S.
FOR SATURDAY NIGHT AND SUNDAY...MAIN CHANGE MADE TO THIS TIME FRAME
WAS TO ADD POPS TO THE FORECAST. YESTERDAY THERE WAS JUST A HINT AT
THE POSSIBILITY OF THE ACTIVITY DEVELOPING ALONG THE HIGH PLAINS
/DRIVEN BY UPSLOPE FLOW AND A WEAK MID LEVEL DISTURBANCE/ SATURDAY
AFTERNOON SLIDING SOUTHEAST AND AFFECTING AT LEAST PORTIONS OF THE
CWA...BUT NOW THE 12Z RUNS OF THE OPERATIONAL MODELS HAVE TRENDED
THIS WAY. ADDED SOME SLIGHT CHANCE AND CHANCE POPS FOR NOW...STILL
SOME SLIGHT VARIATIONS WITH TIMING/LOCATIONS...BUT MOST DO SHOW
ACTIVITY LINGERING INTO THE 12-18Z PERIOD SUNDAY. INSTABILITY IS
PRETTY PATHETIC...MUCAPE VALUES OF ARND 100 J/KG...SO WHILE AN
ISOLATED RUMBLE OF THUNDER OR TWO ARE POSSIBLE...NOT EXPECTING
WIDESPREAD THUNDERSTORMS. DEPENDING ON THE SPEED THIS ACTIVITY
EXISTS...THE HIGHS FOR THE DAY MAY NEED SOME ADJUSTMENT. TRENDED
HIGHS BACK JUST A DEGREE OR TWO OVERALL...BUT IF THINGS LINGER
LONGER THAN CURRENTLY EXPECTED...TEMPS WILL LIKELY STRUGGLE TO REACH
WHAT IS FORECAST /MID 60S TO NEAR 70/.
MONDAY AND TUESDAY...HERE COMES THE WARM UP. PAST FEW RUNS OF THE
MODELS HAVE BEEN PRETTY CONSISTENT WITH THE PATTERN ACROSS THE
CONUS...AT 12Z MONDAY THE CWA IS STILL SITTING UNDER NORTHWESTERLY
FLOW...AS THE CUT OFF LOW CONTINUES TO SIT OVER NRN MEX...AND
RIDGING ORIGINATING OFF THE WEST COAST IS EXTENDED INTO THE
ROCKIES. BY THE END OF THE DAYTIME HRS ON MONDAY AXIS LOOKS TO HAVE
SHIFTED FURTHER EAST INTO THE ROCKIES. WARMER AIR ACCOMPANYING THIS
RIDGE WILL BRING A BUMP UP IN TEMPS MONDAY...AND AGAIN TUESDAY AS
THE CWA REMAINS UNDER ITS INFLUENCE. HIGHS ON MONDAY CURRENTLY
FORECAST TO REACH THE UPPER 70S TO MID 80S...WITH TUESDAY LOOKING AT
MID 80S TO NEAR 90 DEGREES.
A LITTLE MORE UNCERTAINTY IN THE FORECAST ARISES FOR WEDNESDAY AND
THURSDAY...WITH THE POTENTIAL FOR PRECIP RETURNING. THE UPPER LEVEL
RIDGE LOOKS TO BECOME BROKEN DOWN...FROM BOTH THE LOW WHICH HAD BEEN
SET UP OVER MEX SHIFTING EAST INTO THE PLAINS...AND ADDITIONAL
ENERGY SLIDING IN FROM THE PAC NW. PLENTY OF THINGS TO IRON OUT IN
THE COMING DAYS...BUT AT THIS POINT KEPT POPS CONFINED TO THE
WED/THURS DAYTIME PERIOD...HOWEVER HAVE NO DOUBT THE TIMING WILL BE
ADJUSTED. THESE DISTURBANCES LOOK TO BRING THE POTENTIAL FOR SFC
FRONTS MOVING INTO THE AREA...WITH A SLIGHT DECREASE IN TEMPS...WITH
HIGHS BOTH DAYS CURRENTLY IN THE MID 70S TO LOWER 80S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1239 AM CDT FRI MAY 10 2013
THE PRIMARY AVIATION CONCERN WILL CONTINUE TO CENTER AROUND THE
POSSIBILITY OF FOG AS WE NEAR DAWN. AM STILL SEEING THE POTENTIAL
FOR FOG IN FORECAST MODELS...INCLUDING THE HRRR. THEREFORE...WILL
CONTINUE WITH THE LOW CEILING HEIGHTS AND REDUCED VISIBILITIES
FROM THE 00Z TAF...BUT HAVE DELAYED THE ONSET OF THE FOG BY 1 HOUR
BASED ON LATEST MODEL RUNS. THE WIND WILL CONTINUE TO BE LIGHT
THROUGHOUT THE TAF PERIOD AND GENERALLY FROM THE NORTH TODAY.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...SAR
LONG TERM...ADO
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS BUFFALO NY
746 AM EDT FRI MAY 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CROSS OUR AREA TODAY BRINGING MORE RAIN
SHOWERS AND POSSIBLE THUNDERSTORMS. IN THE WAKE OF THIS STORM
SYSTEM...PROGRESSIVELY COOLER AIR WILL FLOOD ACROSS THE REGION THIS
WEEKEND...WITH TEMPERATURES FALLING BACK TO WELL BELOW NORMAL LEVELS
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
RAIN SHOWERS ARE ON THEIR WAY TOWARD WESTERN NEW YORK THIS MORNING
AS A STORM SYSTEM WILL SHIFT EAST ACROSS OUR REGION DURING THE
COURSE OF THE DAY. THE CENTER OF THE SURFACE LOW IS LOCATED NEAR
SOUTHERN MICHIGAN AND WILL TRACK TO THE EAST-NORTHEAST ACROSS
LAKE ERIE THIS AFTERNOON THEN RUNNING JUST NORTH OF LAKE ONTARIO
TONIGHT. CURRENT KBUF RADAR SHOWING LEADING BAND OF RAIN SHOWERS IS
JUST ABOUT TO WORK INTO CHAUTAUQUA COUNTY. OTHERWISE VISIBLE SATELLITE
IS SHOWING HIGH AND MID LEVEL CLOUDS SPREADING EAST ACROSS WESTERN
NEW YORK AHEAD OF THE SYSTEM WITH LOW CLOUDS AND FOG FOUND ACROSS
THE EASTERN LAKE ONTARIO REGION AND THROUGH THE VALLEYS OF THE TWIN
TIERS.
MODEL GUIDANCE INCLUDING LATEST HRRR SHOWS RAIN SHOWERS WILL
ARRIVE ACROSS THE SOUTHERN TIER BETWEEN 12-14Z THE NIAGARA FRONTIER
14-17Z AND THEN ROCHESTER ON EASTWARD THROUGH THE AFTERNOON HOURS.
LATER THIS AFTERNOON THE NAM MODEL SHOWS SOME WEAK INSTABILITY WITH
MLCAPES OF UP TO 500 J/KG...HAVE LEFT CHANCE FOR THUNDERSTORMS IN
THE FORECAST. ADDITIONAL FORCING FOR TODAYS WEATHER IS PROVIDED BY
30-40 KNOT LOW LEVEL JET WHICH MAY MIX DOWN SOME TOWARD THE SURFACE
DURING THE DAY BRINGING SOME WIND GUSTS TO 20-30 MPH RANGE.
DURING THE AFTERNOON HOURS SOME AREAS COULD SEE A BREAK IN SHOWER
ACTIVITY BEFORE A COLD FRONT BRINGS ADDITIONAL RAIN SHOWERS LATER
THIS EVENING. THE COLD FRONT WILL LIKELY CROSS THE FORECAST AREA
BETWEEN MIDNIGHT AND EARLY MORNING WITH CHANCES FOR RAIN SHOWERS
RAPIDLY LOWERING ON ITS HEELS. RAINFALL AMOUNTS WILL RUN BETWEEN A
HALF AND ONE INCH USING BLEND OF SREF AND WPC GUIDANCE WHICH SEEMS
REASONABLE WITH MOIST GREATER THAN ONE INCH PWAT AIRMASS SHIFTING
OVER THE FORECAST AREA AHEAD OF THE SURFACE LOW. ANOTHER DAY OF MILD
TEMPERATURES BUT READING WILL BE CLOSER TO NORMAL. HIGHS WILL RUN IN
THE UPPER 60S TO LOW 70S. LOWS TONIGHT WILL FALL INTO THE UPPER 40S
ACROSS WNY BUT MAY REMAIN IN THE MID 50S OR SO ACROSS CNY AS COLD
FRONT ARRIVES LATER IN THE NIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE SURFACE LOW RESPONSIBLE FOR FRIDAY AND FRIDAY NIGHT/S RAINFALL
WILL BE LIFTING OUT OF THE REGION AND DOWN THE SAINT LAWRENCE VALLEY
ON SATURDAY. THE DEEPEST MOISTURE AND HEAVIEST SHOWERS ASSOCIATED WITH
THIS SYSTEM SHOULD BE PUSHING OUT OF THE NORTH COUNTRY SATURDAY
MORNING...HOWEVER SCATTERED SHOWERS ARE EXPECTED LINGER THROUGH THE
MORNING HOURS ACROSS MUCH OF THE FORECAST AREA AS AN UPPER LEVEL
VORTMAX TRACKS ACROSS WESTERN AND UPSTATE NEW YORK. EXPECT SHOWERS
TO TAPER OFF FROM WEST TO EAST BY THE AFTERNOON AS COOLER AND DRIER
AIR MAKES ITS WAY INTO THE LOWER GREAT LAKES. LOOK FOR TEMEPRATURES
TO DROP BACK BELOW NORMAL AS THIS COOLER AIR FILTERS INTO THE REGION
WITH HIGHS IN THE UPPER 50S TO LOWER 60S...THOUGH TYPICALLY WARMER
SPOTS IN THE GENESEE VALLEY AND FINGER LAKES SHOULD MANAGE TO REACH
THE MID 60S.
LOOK FOR A MUCH MORE SIGNIFICANT DROP IN TEMEPETAURES TO OCCUR
SATURDAY NIGHT AS A POTENT UPPER LEVEL LOW DROPS INTO THE GREAT
LAKES FROM WESTERN ONTARIO...PUSHING A SHARP COLD FRONT ACROSS THE
LOWER GREAT LAKES AHEAD OF IT. EXPECT TERMERPATURES TO DROP INTO THE
UPPER 30S ACROSS WESTERN NEW YORK AND THE SOUITHERN TIER SATURDAY
NIGHT AS MUCH COLDER AND DRIER AIR ADVECTS INTO THE EMPIRE STATE.
ONSHORE FLOW AND A LATER TIMING OF THE FRONTAL PASSAGE OVERNIGHT
SHOULD KEEP THE NORTH COUNTRY AND AREAS NEAR LAKE ONTARIO IN THE
40S. LIMITED MOISTURE MEANS THAT ANY SHOWER ACTVITY
ACCOMPANYING THE FRONTAL PASSAGE SHOULD BE LIMITED TO JUST A FEW
LIGHT SHOWERS AT BEST.
SUNDAY WILL BE COLD AND BLUSTERY AS THE AFORMENTIONED UPPER LEVEL
TRACKS INTO QUEBEC WHILE THE UPPER LEVEL TROUGH AXIS SWINGS ACROSS
THE LOWER GREAT LAKES. WELL ALIGNED WESTERLY FLOW COUPLED WITH
FAIRLY STEEP LOW LEVEL LAPSE RATES THANKS TO THE STRONG COLD
ADVECTION ALOFT WILL ALLOW FOR GOOD MIXING IN THE BOUNDARY
LAYER...RESULTING IN GUSTS OF 25 TO 40 MPH ACROSS MCUH OF THE
FORECAST AREA...PARTICULARLY DOWNWIND OF THE LAKES WHERE GALE FORCE
GUSTS WILL BE POSSIBLE. THE WINDY CONDITIONS WILL SERVE TO FURTHER
EMPHASIZE THE CHILL AS HIGHS ARE ONLY EXPECTED TO REACH THE UPPER
40S TO LOWER 50S WITH WIND CHILLS IN THE 30S. IN ADDITION THE
INSTABILITY INDUCED BY THE COLD ADVECTION ALOFT WILL YIELD PLENTY OF
CLOUD COVER ACROSS THE AREA ALONG WITH A POTENTIAL FOR SCATTERED
RAIN SHOWERS IN THE AFTERNOON.
THE CHILL WILL CONTINUE INTO SUNDAY NIGHT AS THE UPPER LEVEL TROUGH
AND THE CORE OF THE COLD AIR ALOFT CROSSES NEW YORK STATE AS 850MB
TEMPS DROP BELOW -6C. OVERNIGHT LOWS NEAR THE LAKES WILL DROP INTO
THE MID 30S WHILE FARTHER INLAND A HARD FREEZE WILL BE POSSIBLE
ACROSS THE SOUTHERN TIER AS LOWS BOTTOM OUT IN THE UPPER 20S. THE
COMBINATION OF CONTINUED WESTERLY FLOW ACROSS THE LAKES ALONG WITH
THE COLD AIR ALOFT COULD GENERATE LAKE EFFECT
PRECIPITATION...PARTICULARLY EAST OF LAKE ONTARIO WHERE SFC-850MB
DELTA-T VALUES WILL DROP TO -14C. HAVE BUMPED POPS UP TO LIKELY
ACROSS THE NORTH COUTNRY AND GIVEN THAT TEMPS WILL DROP INTO THE MID
30S THERE...WE COULD SEE A RAIN/SNOW MIX ACROSS THE TUG HILL PLATEAU.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE RETURN TO MORE ACTIVE WEATHER WILL CONTINUE THROUGH THE LONG
TERM NOW THAT THE PERSISTENT BLOCKING PATTERN HAS BEEN BROKEN
DOWN...TO BE REPLACED BY A MORE ZONAL FLOW ALONG THE US/CANADIAN
BORDER.
THE UPPER LEVEL TROUGH THAT BROUGHT THE COOL DOWN OVER THE WEEKEND
WILL CONTINUE TO IMPACT THE REGION MONDAY. AS A RESULT HIGHS ON
MONDAY WILL ONLY BE IN THE LOWER TO MID 50S AT BEST...WITH UPPER 40S
ACROSS HIGHER TERRAIN. TEMPS WILL GET COLD ENOUGH MONDAY NIGHT TO
BRING THE POTENTIAL FOR FROST INLAND FROM THE IMMEDIATE LAKESHORES.
THE TROUGH WILL QUICKLY PULL AWAY MONDAY NIGHT AND TUESDAY MORNING
WITH A RETURN TO DRY WEATHER. A WARM FRONT WILL THEN CROSS THE
REGION ON TUESDAY. MODEL GUIDANCE HAS BEEN WAVERING BETWEEN A MAINLY
DRY WARM FRONT OR BETTER SHOWER CHANCES. FOR NOW WILL STICK WITH
PREVIOUS FORECAST CONTINUITY AND KEEP TUESDAY MAINLY DRY.
FROM WEDNESDAY INTO THURSDAY A MUCH WARMER AIRMASS WILL PUSH QUICKLY
EAST ACROSS THE NATION AND INTO OUR REGION AS THE PATTERN REMAINS
PROGRESSIVE AND BEGINS TO DE-AMPLIFY. EXPECT TEMPS TO SOAR TO WELL
ABOVE AVERAGE AGAIN. UNLIKE THE LAST WARM STRETCH...A FRONTAL ZONE
AND MORE ACTIVE FLOW ALOFT WILL BE NEARBY. THIS WILL BRING CHANCES
OF SHOWERS AND EVEN A FEW THUNDERSTORMS TO THE REGION ALONG WITH A
SOMEWHAT MUGGIER AIRMASS.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE ACROSS ALL OF WESTERN NEW YORK THIS
MORNING WITH SHOWERS ARRIVING AT WESTERN NY TERMINALS BEFORE NOON.
EAST OF LAKE ONTARIO SOME MVFR/IFR LOW CLOUDS AND FOG IS BEING
REPORTED AT KFZY/KART/KGTB. THIS SHOULD ERODE BY 14-15Z.
ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE OHIO VALLEY WITH
THICKENING CLOUDS ALREADY ARRIVING ACROSS WNY AT 12Z. RAIN SHOWERS
WILL ARRIVING ACROSS THE REGION FROM WEST TO EAST THROUGH THE DAY.
TAFS INCLUDE -SHRA TIMING BASED ON LATEST HRRR GUIDANCE. A CHANCE OF
A FEW THUNDERSTORMS MAY ALSO BECOME POSSIBLE AS SOME WEAK TO MODEST
INSTABILITY REDEVELOPS IN THE AFTERNOON BUT HAVE LEFT OUT OF THE
TAFS DUE TO LOWER CONFIDENCE AT ANY PARTICULAR SITE. TERMINALS WILL
LOWER BACK TO MVFR/IFR LATER THIS EVENING JUST AHEAD OF AND RIGHT
BEHIND THE SYSTEMS COLD FRONT WHICH SHOULD CROSS THE REGION 06-12Z.
OUTLOOK...
SATURDAY...SHOWERS TAPERING OFF WITH IMPROVEMENT BACK TO MVFR/VFR.
SUNDAY AND MONDAY...MAINLY VFR WITH A CHANCE OF AFTERNOON SHOWERS
BOTH DAYS.
TUESDAY...VFR.
&&
.MARINE...
ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE CENTRAL GREAT
LAKES TODAY AND BRING A RETURN OF MORE SHOWERS AND POSSIBLE
THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...THE PRESSURE GRADIENT ACROSS THE LOWER
LAKES WILL TIGHTEN A LITTLE TODAY. COUPLED WITH STABLE TEMPERATURE
PROFILES DUE TO WARM AIR OVER COOL LAKES...THIS WILL RESULT IN A
CONTINUATION OF RELATIVELY LIGHT WINDS AND MINIMAL WAVES
TONIGHT...BEFORE THESE INCREASE SOMEWHAT ON LAKE ONTARIO.
A PROGRESSIVELY STRONGER WESTERLY FLOW WILL SET UP ACROSS THE LOWER
LAKES REGION BEHIND THE SYSTEMS COLD FRONT GOING INTO THE
WEEKEND...WITH WINDS AND WAVES POSSIBLY INCREASING TO ADVISORY
LEVELS BY SUNDAY AND MAYBE EVEN GALE FORCE ON LAKE ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...HITCHCOCK/WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
438 AM EDT FRI MAY 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CROSS OUR AREA TODAY BRINGING MORE RAIN
SHOWERS AND POSSIBLE THUNDERSTORMS. IN THE WAKE OF THIS STORM
SYSTEM...PROGRESSIVELY COOLER AIR WILL FLOOD ACROSS THE REGION THIS
WEEKEND...WITH TEMPERATURES FALLING BACK TO WELL BELOW NORMAL LEVELS
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID-LEVEL RIDGE CENTERED OVER NEW YORK EARLY THIS MORNING. SATELLITE
IMAGERY IS SHOWING LAYER OF HIGH CLOUDS SHIFTING ACROSS WESTERN
COUNTIES OUT AHEAD OF A STORM SYSTEM OVER OHIO WITH SOME LOW CLOUDS
AND FOG FOUND EAST OF LAKE ONTARIO. WITHIN THESE LOWER CLOUDS...
KTYX RADAR IS SHOWING A FEW SHOWERS DRIFTING SOUTHEAST ACROSS
NORTHERN NEW YORK WHICH ARE THE LAST REMNANTS OF THE STORM SYSTEM
WHICH BROUGHT RAIN YESTERDAY. THE CURRENT SHOWERS ARE VERIFYING THE
LATEST HRRR MODEL RUN SO HAVE CONTINUED TO FEATURE A CHANCE FOR
SHOWERS ACROSS EASTERN LAKE ONTARIO COUNTIES THROUGH THE EARLY
MORNING. IN ADDITION TO THE SHOWERS SOME FOG IS BEING REPORTED AT
KFZY AND KART SO WILL CONTINUE TO INCLUDE PATCHY FOG IN THIS
MORNINGS FORECAST. TEMPERATURES ARE RUNNING A LITTLE ABOVE
NORMAL...WITH EARLY MORNING LOWS EXPECTED TO RANGE FROM THE MID
AND UPPER 40S IN THE COOLER SOUTHERN TIER VALLEYS TO THE MID 50S ACROSS
PARTS OF THE FINGER LAKES AND LAKE PLAINS.
RAIN SHOWERS ARE IN THE FORECAST FOR TODAY WITH A CHANCE FOR SOME
THUNDER AS A STORM SYSTEM TO OUR WEST WILL SHIFT EAST ACROSS OUR
REGION DURING THE COURSE OF THE DAY. THE CENTER OF THE SURFACE LOW IS
LOCATED NEAR SOUTHERN LAKE MICHIGAN AND WILL TRACK TO THE
EAST-NORTHEAST ACROSS LAKE ERIE THIS AFTERNOON THEN RUNNING JUST
NORTH OF LAKE ONTARIO TONIGHT. CURRENT GREAT LAKES REGIONAL RADAR
MOSAIC SHOWING LEADING BAND OF THUNDERSTORMS OVER OHIO WITH RAIN
SHOWERS SPREAD TO THE NORTH AND WEST BACK TOWARD THE CENTER OF THE
LOW.
MODEL GUIDANCE INCLUDING LATEST HRRR SHOWS RAIN SHOWERS WILL
ARRIVE ACROSS THE SOUTHERN TIER BETWEEN 12-14Z THE NIAGARA FRONTIER
14-17Z AND THEN ROCHESTER ON EASTWARD THROUGH THE AFTERNOON HOURS.
NOT EXPECTING THE CURRENT THUNDERSTORMS OVER OHIO TO REACH INTO OUR
FORECAST AREA THIS MORNING. THE HRRR MODEL SHOWS THESE WILL STAY
JUST TO THE SOUTH ACROSS PA. LATER THIS AFTERNOON THE NAM MODEL
SHOWS SOME WEAK INSTABILITY WITH MLCAPES OF UP TO 500 J/KG...HAVE
LEFT CHANCE FOR THUNDERSTORMS IN THE FORECAST. ADDITIONAL FORCING FOR
TODAYS WEATHER IS PROVIDED BY 30-40 KNOT LOW LEVEL JET WHICH MAY MIX
DOWN SOME TOWARD THE SURFACE DURING THE DAY BRINGING SOME WIND GUSTS
TO 20-30 MPH RANGE.
DURING THE AFTERNOON HOURS SOME AREAS COULD SEE A BREAK IN SHOWER
ACTIVITY BEFORE A COLD FRONT BRINGS ADDITIONAL RAIN SHOWERS LATER
THIS EVENING. THE COLD FRONT WILL LIKELY CROSS THE FORECAST AREA
BETWEEN MIDNIGHT AND EARLY MORNING WITH CHANCES FOR RAIN SHOWERS
RAPIDLY LOWERING ON ITS HEELS. RAINFALL AMOUNTS WILL RUN BETWEEN A
HALF AND ONE INCH USING BLEND OF SREF AND WPC GUIDANCE WHICH SEEMS
REASONABLE WITH MOIST GREATER THAN ONE INCH PWAT AIRMASS SHIFTING
OVER THE FORECAST AREA AHEAD OF THE SURFACE LOW. ANOTHER DAY OF MILD
TEMPERATURES BUT READING WILL BE CLOSER TO NORMAL. HIGHS WILL RUN IN
THE UPPER 60S TO LOW 70S. LOWS TONIGHT WILL FALL INTO THE UPPER 40S
ACROSS WNY BUT MAY REMAIN IN THE MID 50S OR SO ACROSS CNY AS COLD
FRONT ARRIVES LATER IN THE NIGHT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
THE SURFACE LOW RESPONSIBLE FOR FRIDAY AND FRIDAY NIGHT/S RAINFALL
WILL BE LIFTING OUT OF THE REGION AND DOWN THE SAINT LAWRENCE VALLEY
ON SATURDAY. THE DEEPEST MOISTURE AND HEAVIEST SHOWERS ASSOCIATED WITH
THIS SYSTEM SHOULD BE PUSHING OUT OF THE NORTH COUNTRY SATURDAY
MORNING...HOWEVER SCATTERED SHOWERS ARE EXPECTED LINGER THROUGH THE
MORNING HOURS ACROSS MUCH OF THE FORECAST AREA AS AN UPPER LEVEL
VORTMAX TRACKS ACROSS WESTERN AND UPSTATE NEW YORK. EXPECT SHOWERS
TO TAPER OFF FROM WEST TO EAST BY THE AFTERNOON AS COOLER AND DRIER
AIR MAKES ITS WAY INTO THE LOWER GREAT LAKES. LOOK FOR TEMEPRATURES
TO DROP BACK BELOW NORMAL AS THIS COOLER AIR FILTERS INTO THE REGION
WITH HIGHS IN THE UPPER 50S TO LOWER 60S...THOUGH TYPICALLY WARMER
SPOTS IN THE GENESEE VALLEY AND FINGER LAKES SHOULD MANAGE TO REACH
THE MID 60S.
LOOK FOR A MUCH MORE SIGNIFICANT DROP IN TEMEPETAURES TO OCCUR
SATURDAY NIGHT AS A POTENT UPPER LEVEL LOW DROPS INTO THE GREAT
LAKES FROM WESTERN ONTARIO...PUSHING A SHARP COLD FRONT ACROSS THE
LOWER GREAT LAKES AHEAD OF IT. EXPECT TERMERPATURES TO DROP INTO THE
UPPER 30S ACROSS WESTERN NEW YORK AND THE SOUITHERN TIER SATURDAY
NIGHT AS MUCH COLDER AND DRIER AIR ADVECTS INTO THE EMPIRE STATE.
ONSHORE FLOW AND A LATER TIMING OF THE FRONTAL PASSAGE OVERNIGHT
SHOULD KEEP THE NORTH COUNTRY AND AREAS NEAR LAKE ONTARIO IN THE
40S. LIMITED MOISTURE MEANS THAT ANY SHOWER ACTVITY
ACCOMPANYING THE FRONTAL PASSAGE SHOULD BE LIMITED TO JUST A FEW
LIGHT SHOWERS AT BEST.
SUNDAY WILL BE COLD AND BLUSTERY AS THE AFORMENTIONED UPPER LEVEL
TRACKS INTO QUEBEC WHILE THE UPPER LEVEL TROUGH AXIS SWINGS ACROSS
THE LOWER GREAT LAKES. WELL ALIGNED WESTERLY FLOW COUPLED WITH
FAIRLY STEEP LOW LEVEL LAPSE RATES THANKS TO THE STRONG COLD
ADVECTION ALOFT WILL ALLOW FOR GOOD MIXING IN THE BOUNDARY
LAYER...RESULTING IN GUSTS OF 25 TO 40 MPH ACROSS MCUH OF THE
FORECAST AREA...PARTICULARLY DOWNWIND OF THE LAKES WHERE GALE FORCE
GUSTS WILL BE POSSIBLE. THE WINDY CONDITIONS WILL SERVE TO FURTHER
EMPHASIZE THE CHILL AS HIGHS ARE ONLY EXPECTED TO REACH THE UPPER
40S TO LOWER 50S WITH WIND CHILLS IN THE 30S. IN ADDITION THE
INSTABILITY INDUCED BY THE COLD ADVECTION ALOFT WILL YIELD PLENTY OF
CLOUD COVER ACROSS THE AREA ALONG WITH A POTENTIAL FOR SCATTERED
RAIN SHOWERS IN THE AFTERNOON.
THE CHILL WILL CONTINUE INTO SUNDAY NIGHT AS THE UPPER LEVEL TROUGH
AND THE CORE OF THE COLD AIR ALOFT CROSSES NEW YORK STATE AS 850MB
TEMPS DROP BELOW -6C. OVERNIGHT LOWS NEAR THE LAKES WILL DROP INTO
THE MID 30S WHILE FARTHER INLAND A HARD FREEZE WILL BE POSSIBLE
ACROSS THE SOUTHERN TIER AS LOWS BOTTOM OUT IN THE UPPER 20S. THE
COMBINATION OF CONTINUED WESTERLY FLOW ACROSS THE LAKES ALONG WITH
THE COLD AIR ALOFT COULD GENERATE LAKE EFFECT
PRECIPITATION...PARTICULARLY EAST OF LAKE ONTARIO WHERE SFC-850MB
DELTA-T VALUES WILL DROP TO -14C. HAVE BUMPED POPS UP TO LIKELY
ACROSS THE NORTH COUTNRY AND GIVEN THAT TEMPS WILL DROP INTO THE MID
30S THERE...WE COULD SEE A RAIN/SNOW MIX ACROSS THE TUG HILL PLATEAU.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
THE RETURN TO MORE ACTIVE WEATHER WILL CONTINUE THROUGH THE LONG
TERM NOW THAT THE PERSISTENT BLOCKING PATTERN HAS BEEN BROKEN
DOWN...TO BE REPLACED BY A MORE ZONAL FLOW ALONG THE US/CANADIAN
BORDER.
THE UPPER LEVEL TROUGH THAT BROUGHT THE COOL DOWN OVER THE WEEKEND
WILL CONTINUE TO IMPACT THE REGION MONDAY. AS A RESULT HIGHS ON
MONDAY WILL ONLY BE IN THE LOWER TO MID 50S AT BEST...WITH UPPER 40S
ACROSS HIGHER TERRAIN. TEMPS WILL GET COLD ENOUGH MONDAY NIGHT TO
BRING THE POTENTIAL FOR FROST INLAND FROM THE IMMEDIATE LAKESHORES.
THE TROUGH WILL QUICKLY PULL AWAY MONDAY NIGHT AND TUESDAY MORNING
WITH A RETURN TO DRY WEATHER. A WARM FRONT WILL THEN CROSS THE
REGION ON TUESDAY. MODEL GUIDANCE HAS BEEN WAVERING BETWEEN A MAINLY
DRY WARM FRONT OR BETTER SHOWER CHANCES. FOR NOW WILL STICK WITH
PREVIOUS FORECAST CONTINUITY AND KEEP TUESDAY MAINLY DRY.
FROM WEDNESDAY INTO THURSDAY A MUCH WARMER AIRMASS WILL PUSH QUICKLY
EAST ACROSS THE NATION AND INTO OUR REGION AS THE PATTERN REMAINS
PROGRESSIVE AND BEGINS TO DE-AMPLIFY. EXPECT TEMPS TO SOAR TO WELL
ABOVE AVERAGE AGAIN. UNLIKE THE LAST WARM STRETCH...A FRONTAL ZONE
AND MORE ACTIVE FLOW ALOFT WILL BE NEARBY. THIS WILL BRING CHANCES
OF SHOWERS AND EVEN A FEW THUNDERSTORMS TO THE REGION ALONG WITH A
SOMEWHAT MUGGIER AIRMASS.
&&
.AVIATION /09Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE ACROSS ALL OF WESTERN NEW YORK THIS
MORNING BUT EAST OF LAKE ONTARIO SOME MVFR/IFR IS BEING REPORTED AT
KFZY AND KART. THIS WILL CONTINUE THROUGH THE MORNING HOURS BREAKING
UP AFTER SUNRISE.
LATER TODAY...ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE
OHIO VALLEY WITH THICKENING CLOUDS AND RAIN SHOWERS ARRIVING ACROSS
THE REGION FROM SOUTHWEST TO NORTHEAST. UPDATED TAFS WITH LATEST
HRRR GUIDANCE FOR START TIME OF -SHRA. A CHANCE OF A FEW
THUNDERSTORMS MAY ALSO BECOME POSSIBLE AS SOME WEAK TO MODEST
INSTABILITY REDEVELOPS IN THE AFTERNOON BUT HAVE LEFT OUT OF THE
TAFS DUE TO LOWER CONFIDENCE AT ANY PARTICULAR SITE. TERMINALS WILL
LOWER BACK TO MVFR/IFR LATER THIS EVENING WHEN THE SYSTEMS COLD FRONT
SHIFTS TOWARD WNY WITH BETTER COVERAGE OF RAIN SHOWERS AND LOWER CIGS.
OUTLOOK...
SATURDAY...SHOWERS TAPERING OFF WITH IMPROVEMENT BACK TO MVFR/VFR.
SUNDAY AND MONDAY...MAINLY VFR WITH A CHANCE OF AFTERNOON SHOWERS
BOTH DAYS.
TUESDAY...VFR.
&&
.MARINE...
A BRIEF PERIOD OF QUIETER AND DRIER WEATHER CAN BE EXPECTED
OVERNIGHT...BEFORE ANOTHER LOW PRESSURE SYSTEM PUSHES EAST FROM THE
CENTRAL GREAT LAKES LATER THIS MORNING AND BRINGS A RETURN OF MORE
SHOWERS AND POSSIBLE THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...THE PRESSURE GRADIENT ACROSS THE LOWER
LAKES WILL REMAIN WEAK OVERNIGHT...BEFORE TIGHTENING A LITTLE LATER
TODAY. COUPLED WITH STABLE TEMPERATURE PROFILES...THIS WILL RESULT IN A
CONTINUATION OF RELATIVELY LIGHT WINDS AND MINIMAL WAVES
TONIGHT...BEFORE THESE INCREASE SOMEWHAT ON LAKE ONTARIO. THE ABOVE
SAID...THESE SHOULD STILL REMAIN BELOW ADVISORY CRITERIA.
BEHIND THE SECOND LOW...A PROGRESSIVELY STRONGER WESTERLY FLOW WILL
SET UP ACROSS THE LOWER LAKES REGION OVER THE WEEKEND...WITH WINDS
AND WAVES POSSIBLY INCREASING TO ADVISORY LEVELS BY SUNDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...HITCHCOCK/WOOD
AVIATION...SMITH
MARINE...SMITH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
214 AM EDT FRI MAY 10 2013
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CROSS OUR AREA TODAY BRINGING MORE RAIN
SHOWERS AND POSSIBLE THUNDERSTORMS. IN THE WAKE OF THIS STORM
SYSTEM...PROGRESSIVELY COOLER AIR WILL FLOOD ACROSS THE REGION THIS
WEEKEND...WITH TEMPERATURES FALLING BACK TO WELL BELOW NORMAL LEVELS
FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
MID-LEVEL RIDGE IS SHIFTING OVER NEW YORK EARLY THIS MORNING WITH
ITS AXIS CENTERED JUST TO OUR WEST. SATELLITE IMAGERY IS SHOWING
LAYER OF HIGH CLOUDS SHIFTING ACROSS WESTERN COUNTIES OUT AHEAD OF A
STORM SYSTEM OVER WESTERN OHIO WITH SOME LOW CLOUDS EAST OF LAKE ONTARIO.
WITHIN THESE LOWER CLOUDS... KTYX RADAR IS SHOWING A FEW SHOWERS
DRIFTING SOUTHEAST ACROSS NORTHERN NEW YORK WHICH ARE THE LAST
REMNANTS OF THE STORM SYSTEM WHICH BROUGHT RAIN YESTERDAY. THE
CURRENT SHOWERS ARE VERIFYING THE LATEST HRRR MODEL RUN SHOW HAVE
CONTINUED TO FEATURE A CHANCE FOR SHOWERS ACROSS EASTERN LAKE
ONTARIO COUNTIES THROUGH THE EARLY MORNING. IN ADDITION TO THE
SHOWERS SOME FOG IS BEING REPORTED AT KFZY AND KART SO WILL CONTINUE
TO INCLUDE PATCHY FOG IN THIS MORNINGS FORECAST. OVERNIGHT
TEMPERATURES WILL REMAIN A LITTLE ABOVE NORMAL...WITH EARLY MORNING
LOWS RANGING FROM THE MID AND UPPER 40S IN THE COOLER SRN TIER
VALLEYS TO THE MID 50S ACROSS PARTS OF THE FINGER LAKES AND LAKE
PLAINS.
LATER THIS MORNING...THE NEXT PACIFIC-BASED SHORTWAVE TROUGH AND
ASSOCIATED SURFACE LOW OVER THE WESTERN GREAT LAKES HEADS EASTWARD
INTO OUR REGION. INCREASING WARM AIR ADVECTION OUT AHEAD OF THIS LOW
WILL LEAD TO THICKENING CLOUDS AND MORE SHOWERS SPREADING BACK
ACROSS OUR AREA FROM SOUTHWEST TO NORTHEAST...WITH THESE FOCUSING ON
THE NOSE OF SEVERAL 30-40 KT LOW-MID LEVEL JET SEGMENTS THAT WILL
BODILY LIFT NORTHEAST FROM THE OHIO VALLEY. USING THE FASTER GFS
/WHICH TYPICALLY HANDLES THE SPEED OF WARM AIR ADVECTION-DRIVEN
PRECIP THE BEST/ AS A GUIDE FOR TIMING...SOME OF THESE SHOWERS MAY
REACH FAR SOUTHWESTERN NEW YORK AS EARLY AS 12-13Z FRIDAY
MORNING...THE BUFFALO AREA BY 14Z-15Z...AND KROC AND POINTS EASTWARD
BY EARLY FRIDAY AFTERNOON.
GIVEN THE FAIRLY IMPRESSIVE WARM AIR ADVECTION PATTERN AND
INCREASING LARGE-SCALE LIFT COUPLED WITH PWATS INCREASING TO BETWEEN
1 AND 1.5 INCHES...FEEL THAT SHOWERS WILL EVENTUALLY BECOME A NEAR
CERTAINTY WITH TIME ON FRIDAY...THUS WILL INDICATE POPS INCREASING
TO HIGH-END CATEGORICAL LEVELS. LIKEWISE...GIVEN THE OVERALL PATTERN
AND THE DEVELOPMENT OF SOME WEAK TO MODEST INSTABILITY AS SHOWN BY
THE BULK OF THE GUIDANCE...WILL ALSO CONTINUE TO INDICATE THE CHANCE
FOR SOME EMBEDDED THUNDERSTORMS AS WELL.
TEMPERATURE-WISE...HIGHS TODAY WILL AGAIN BE ABOVE AVERAGE WITH
READINGS RANGING FROM THE UPPER 60S TO MID 70S...AND THE WARMEST
TEMPS GENERALLY OVER INTERIOR SECTIONS OF THE GENESEE VALLEY AND
FINGER LAKES.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...
FRIDAY NIGHT A SURFACE LOW WILL PASS JUST NORTH OF LAKES ERIE AND
ONTARIO...WITH AN ASSOCIATED STRONG MID LEVEL SHORTWAVE CROSSING THE
REGION BRINGING A PERIOD OF LARGE SCALE ASCENT. A LOW LEVEL JET
SEGMENT WILL ALSO CROSS THE AREA...THE NOSE OF WHICH IS FORECAST TO
MOVE FROM THE SOUTHERN TIER ACROSS THE FINGER LAKES TO THE EASTERN
LAKE ONTARIO REGION OVERNIGHT. THIS WILL ENHANCE LOW LEVEL
CONVERGENCE AND ASCENT...AND SHOULD CORRESPOND TO THE TRACK OF
HEAVIEST RAINFALL. PWAT VALUES WILL INCREASE TO AROUND 1.5 INCHES...
WHICH WILL COMBINE WITH THE QUALITY DYNAMICS TO PRODUCE WIDESPREAD
SHOWERS ACROSS THE REGION. SOME AREAS MAY SEE UP TO AN INCH OF
RAIN...MOST LIKELY FOLLOWING THE PATH OF THE LOW LEVEL JET FROM THE
SOUTHERN TIER INTO CENTRAL NY. THERE IS ENOUGH INSTABILITY TO
SUPPORT A FEW EMBEDDED THUNDERSTORMS AS WELL WITH LOCALLY HIGHER
RAINFALL AMOUNTS.
LATE FRIDAY NIGHT AND SATURDAY THE RAIN WILL TAPER OFF FROM WEST TO
EAST AS THE SURFACE LOW AND ASSOCIATED SHORTWAVE AND LOW LEVEL JET
MOVES EAST INTO NEW ENGLAND. MODEL GUIDANCE STILL SHOWS A GOOD
AMOUNT OF LOW LEVEL MOISTURE LINGERING INTO SATURDAY MORNING WITH
PLENTY OF CLOUD COVER...ALTHOUGH SOME BREAKS SHOULD DEVELOP LATER IN
THE AFTERNOON. 850MB TEMPS ARE STILL ON THE MILD SIDE AT +4C TO +5C
SO THIS SHOULD STILL SUPPORT HIGHS IN THE 60S DESPITE CLOUD COVER.
SATURDAY NIGHT A SHARP TROUGH WILL DIG INTO THE NORTHERN GREAT LAKES
AND FORCE A STRONG COLD FRONT EAST ACROSS OUR REGION. MOST OF THE
DEEP MOISTURE AND LARGE SCALE ASCENT WILL BE GONE...ASSOCIATED WITH
THE FIRST SYSTEM. STILL...GIVEN THE STRENGTH OF THE COLD FRONT
EXPECT A PERIOD OF SCATTERED SHOWERS TO MOVE FROM WEST TO EAST
ACROSS THE AREA OVERNIGHT.
THIS FRONT WILL USHER IN A MUCH COLDER AIRMASS FOR THE REST OF THE
WEEKEND. STEADY COLD AIR ADVECTION ON SUNDAY WILL KEEP HIGHS IN THE
LOWER TO MID 50S ACROSS LOWER ELEVATIONS...AND BARELY 50 ACROSS
HIGHER TERRAIN. THE DAY SHOULD START OFF DRY...BUT COLD AIR ALOFT
COMBINED WITH THE STRONG MID MAY SUN ANGLE WILL PROMOTE CUMULUS AND
STRATOCUMULUS DEVELOPMENT ALONG WITH SCATTERED SHOWERS DURING THE
AFTERNOON.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE RETURN TO MORE ACTIVE WEATHER WILL CONTINUE THROUGH THE LONG
TERM NOW THAT THE PERSISTENT BLOCKING PATTERN HAS BEEN BROKEN
DOWN...TO BE REPLACED BY A MORE ZONAL FLOW ALONG THE US/CANADIAN
BORDER.
SUNDAY NIGHT INTO MONDAY A DEEP LONGWAVE TROUGH WILL DIG INTO THE
LOWER LAKES AND NEW ENGLAND. THIS WILL BRING A SHARP...BUT BRIEF
SHOT OF COLD AIR TO THE REGION. HIGHS ON MONDAY WILL ONLY BE IN THE
LOWER TO MID 50S AT BEST...WITH UPPER 40S ACROSS HIGHER TERRAIN.
TEMPS WILL GET COLD ENOUGH BOTH SUNDAY NIGHT AND MONDAY NIGHT TO
BRING THE POTENTIAL FOR FROST INLAND FROM THE IMMEDIATE
LAKESHORES...ALTHOUGH SUNDAY NIGHT CLOUD COVER MAY HELP TO PROTECT
SOME AREAS FROM FROST. HAVE NOT INCLUDED ANY MENTION OF SNOW YET...
BUT IF ANY PRECIP IS STILL IN THE AREA LATE SUNDAY NIGHT AND MONDAY
MORNING A FEW WET FLAKES OR GRAUPEL PELLETS MAY MIX IN.
THE TROUGH WILL QUICKLY PULL AWAY MONDAY NIGHT AND TUESDAY MORNING
WITH A RETURN TO DRY WEATHER. A WARM FRONT WILL THEN CROSS THE
REGION ON TUESDAY. MODEL GUIDANCE HAS BEEN WAVERING BETWEEN A MAINLY
DRY WARM FRONT OR BETTER SHOWER CHANCES. FOR NOW WILL STICK WITH
PREVIOUS FORECAST CONTINUITY AND KEEP TUESDAY MAINLY DRY.
FROM WEDNESDAY INTO THURSDAY A MUCH WARMER AIRMASS WILL PUSH QUICKLY
EAST ACROSS THE NATION AND INTO OUR REGION AS THE PATTERN REMAINS
PROGRESSIVE AND BEGINS TO DE-AMPLIFY. EXPECT TEMPS TO SOAR TO WELL
ABOVE AVERAGE AGAIN. UNLIKE THE LAST WARM STRETCH...A FRONTAL ZONE
AND MORE ACTIVE FLOW ALOFT WILL BE NEARBY. THIS WILL BRING CHANCES
OF SHOWERS AND EVEN A FEW THUNDERSTORMS TO THE REGION ALONG WITH A
SOMEWHAT MUGGIER AIRMASS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL CONTINUE ACROSS ALL OF WESTERN NEW YORK THIS
MORNING BUT EAST OF LAKE ONTARIO SOME MVFR/IFR IS BEING REPORTED AT
KFZY AND KART. THIS WILL CONTINUE THROUGH THE MORNING HOURS BREAKING
UP AFTER SUNRISE.
LATER TODAY...ANOTHER LOW PRESSURE SYSTEM WILL PUSH EAST FROM THE
OHIO VALLEY WITH THICKENING CLOUDS AND RAIN SHOWERS ARRIVING ACROSS
THE REGION FROM SOUTHWEST TO NORTHEAST. UPDATED TAFS WITH LATEST
HRRR GUIDANCE FOR START TIME OF -SHRA. A CHANCE OF A FEW
THUNDERSTORMS MAY ALSO BECOME POSSIBLE AS SOME WEAK TO MODEST
INSTABILITY REDEVELOPS IN THE AFTERNOON BUT HAVE LEFT OUT OF THE
TAFS DUE TO LOWER CONFIDENCE AT ANY PARTICULAR SITE. TERMINALS WILL
LOWER BACK TO MVFR/IFR LATER THIS EVENING WHEN THE SYSTEMS COLD FRONT
SHIFTS TOWARD WNY WITH BETTER COVERAGE OF RAIN SHOWERS AND LOWER CIGS.
OUTLOOK...
SATURDAY...SHOWERS TAPERING OFF WITH IMPROVEMENT BACK TO MVFR/VFR.
SUNDAY AND MONDAY...MAINLY VFR WITH A CHANCE OF AFTERNOON SHOWERS
BOTH DAYS.
TUESDAY...VFR.
&&
.MARINE...
A BRIEF PERIOD OF QUIETER AND DRIER WEATHER CAN BE EXPECTED
OVERNIGHT...BEFORE ANOTHER LOW PRESSURE SYSTEM PUSHES EAST FROM THE
CENTRAL GREAT LAKES LATER THIS MORNING AND BRINGS A RETURN OF MORE
SHOWERS AND POSSIBLE THUNDERSTORMS.
IN TERMS OF WINDS AND WAVES...THE PRESSURE GRADIENT ACROSS THE LOWER
LAKES WILL REMAIN WEAK OVERNIGHT...BEFORE TIGHTENING A LITTLE LATER
TODAY. COUPLED WITH STABLE TEMPERATURE PROFILES...THIS WILL RESULT IN A
CONTINUATION OF RELATIVELY LIGHT WINDS AND MINIMAL WAVES
TONIGHT...BEFORE THESE INCREASE SOMEWHAT ON LAKE ONTARIO. THE ABOVE
SAID...THESE SHOULD STILL REMAIN BELOW ADVISORY CRITERIA.
BEHIND THE SECOND LOW...A PROGRESSIVELY STRONGER WESTERLY FLOW WILL
SET UP ACROSS THE LOWER LAKES REGION OVER THE WEEKEND...WITH WINDS
AND WAVES POSSIBLY INCREASING TO ADVISORY LEVELS BY SUNDAY.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...JJR/SMITH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...SMITH
MARINE...JJR/SMITH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
107 PM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 105 PM CDT FRI MAY 10 2013
NO MAJOR CHANGES WERE MADE TO THE FORECAST FOR THIS UPDATE. A COLD
FRONT LOCATED JUST NORTH OF BISMARCK CONTINUES TO PUSH SOUTH AND
SHOULD BE OUT OF NORTH DAKOTA LATER THIS AFTERNOON. BEHIND THE
FRONT WINDS CONTINUE TO STRONG WITH GUSTS UP TO 40 MPH. ALL
FORECAST GRIDS HAVE BEEN UPDATED TO REFLECT CURRENT TRENDS AND
OBSERVATIONS.
UPDATE ISSUED AT 1035 AM CDT FRI MAY 10 2013
THE MAIN IMPACTS FOR THE SHORT TERM UPDATE ARE GUSTY WINDS AND FIRE
DANGER.
A STRONG COLD FRONT CURRENTLY LOCATED NEAR MINOT WILL QUICKLY
BLAST SOUTH OUT OF NORTH DAKOTA BY LATE AFTERNOON. BEHIND THE
FRONT PRESSURE RISES NEAR 5 MB WITHIN THE LAST THREE HOURS WILL
DRIVE SUSTAINED WINDS NEAR 30 MPH AND FREQUENT GUSTS UP TO 45 MPH.
THEREFORE A WIND ADVISORY WAS ISSUED. THESE GUSTY WINDS AND VERY
DRY AIR WILL CONTINUE TO DRIVE DOWN RELATIVE HUMIDITIES AND FIRE
DANGER UP.
PRECIPITATION CHANCES WERE LOWERED FOR THIS UPDATE. LATEST GUIDANCE
FROM THE 13 UTC RAP AND 14 UTC HRRR SHOW VERY LITTLE PRECIPITATION
DEVELOPING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE
AFTERNOON HOURS. LATEST OBSERVATIONS SHOW VERY DRY AIR AT THE
SURFACE AND ONLY LIGHT RAIN SHOWER ECHOS SHOWING UP ON RADAR. BEST
CHANCE OF PRECIPITATION STILL LOOKS TO BE ACROSS FAR SOUTHERN
NORTH DAKOTA LATE THIS AFTERNOON AS PEAK HEATING WILL INCREASE
INSTABILITY AND PROXIMITY TO A MORE MOIST AIRMASS MAY PROVIDE ENOUGH
TO SPAWN SOME SCATTERED SHOWERS AND THUNDERSTORMS.
UPDATE ISSUED AT 652 AM CDT FRI MAY 10 2013
COLD FRONT EXTENDING SOUTHWEST FROM A SURFACE LOW NEAR LAKE
WINNIPEG WILL MOVE INTO NORTHWEST NORTH DAKOTA SHORTLY. INCREASING
CLOUDS AND A FEW SHOWERS SHOWING UP OVER SOUTHERN SASKATCHEWAN AND
MANITOBA. CURRENT FORECAST HAS A GOOD HANDLE ON CURRENT PLACEMENT
OF CLOUDS AND PRECIPITATION. ONLY CHANGES TO THE FORECAST WERE TO
UPDATE CURRENT SENSIBLE WEATHER ELEMENTS. THIS DROPPED OUR
OVERNIGHT LOWS SOME ACROSS CENTRAL NORTH DAKOTA WHERE CLEAR SKIES
AND LIGHT WINDS ALLOWED TEMPERATURES TO DROP A BIT BELOW FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT FRI MAY 10 2013
MAIN HIGHLIGHT FOR THE SHORT TERM WILL BE THE APPROACHING COLD FRONT
AND RESULTING WEATHER IMPACTS INCLUDING FIRE WEATHER CONCERNS.
CURRENTLY...WATER VAPOR SATELLITE IMAGERY INDICATES UPPER LEVEL
SHORTWAVE OVER SOUTHERN MANITOBA/SASKATCHEWAN MOVING SOUTHEASTWARD.
THIS FEATURE HANDLED WELL BY THE MODELS AND WILL USE A MODEL BLEND
FOR FORECAST DETAILS. SURFACE COLD FRONT ASSOCIATED WITH THE UPPER
LEVEL SHORTWAVE EXTENDED FROM NORTHERN LAKE WINNIPEG ACROSS SOUTHERN
SASKATCHEWAN TO NORTH CENTRAL MONTANA. AHEAD OF THE FRONT WINDS WERE
LIGHT AND FROM THE SOUTH.
THE COLD FRONT IS PROGGED TO REACH THE NORTHWEST CORNER OF THE STATE
AROUND SUNRISE AND CONTINUE MOVING SOUTHEASTWARD. BY AROUND NOON CDT
THE FRONT SHOULD BE APPROACHING DICKINSON/GARRISON/DEVILS LAKE AREA
AND REACH THE JAMESTOWN AREA BY MID-LATE AFTERNOON. AHEAD OF THE
FRONT THE SOUTH WINDS SHOULD BECOME MORE SOUTHWESTERLY AND BEGIN
INCREASING...THEN AFTER THE FRONT PASSES WINDS SHOULD BECOME
NORTHWEST AND INCREASE TO 20 TO 30 MPH. BUFKIT SOUNDINGS AND LOOKING
AT H850 FORECAST WINDS...THERE SHOULD BE GOOD LINKAGE ALOFT TO ABOVE
H800 AND WINDS AROUND H850 ARE AROUND 30 KNOTS. THUS SUSTAINED WINDS
SHOULD BE JUST SHY OF WIND ADVISORY CRITERIA OF 30 MPH FOR 3 HOURS
OR MORE. WIND GUSTS COULD BE AS HIGH AS 35 TO POSSIBLY 40 MPH IN
SOME LOCALES.
THESE STRONG WINDS COMBINED WITH DRY GRASSLANDS WILL RAISE FIRE
WEATHER CONCERNS. SEE THE FIRE WEATHER SECTION BELOW FOR DETAILS.
THE COLD FRONT IS PROGGED TO EXTEND ACROSS SOUTHERN NORTH DAKOTA
THIS AFTERNOON - DURING PEAK HEATING OF THE DAY. CAPE VALUES ARE
200-400 FOR THE MID AND LATE AFTERNOON/EARLY EVENING HOURS AND WILL
KEEP THE CHANCE OF RAIN SHOWERS NORTHWEST AND NORTH CENTRAL NORTH
DAKOTA THIS MORNING AND THUNDERSHOWERS SOUTHWEST AND SOUTH CENTRAL
THIS AFTERNOON. LOOKING AT HIGH TEMPERATURES FROM THE 60S NORTH TO
THE LOW TO MID 70S SOUTH.
WINDS SHOULD DECREASE DURING THE EVENING WITH COOL AND DRY AIR
PUSHING INTO THE STATE. LOWS TONIGHT SHOULD DIP INTO THE 20S TO
LOWER 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 410 AM CDT FRI MAY 10 2013
WE BEGIN THE EXTENDED PERIOD ON THE COOL SIDE WITH CANADIAN HIGH
PRESSURE OVER THE REGION SATURDAY MORNING. STRONG UPPER LEVEL
RIDGING OVER THE WESTERN U.S. SATURDAY WILL TRANSLATE EAST THROUGH
THE WEEKEND BRINGING WARMER TEMPERATURES TO WESTERN NORTH DAKOTA ON
SUNDAY. DRY CONDITIONS ARE EXPECTED SATURDAY THROUGH SUNDAY.
A WEAK SURFACE TROUGH MOVES INTO THE AREA SUNDAY NIGHT...ASSOCIATED
WITH A NORTHERN STREAM WAVE THAT FLATTENS THE UPPER RIDGE THAT HAS
MOVED OVER THE NORTHERN PLAINS. MODELS ARE DEPICTING VERY LIGHT QPF
ALONG THE TROUGH BUT WITH ABUNDANT DRY AIR OVER THE REGION...WILL
HOLD OFF ON INTRODUCING A MENTION OF SHOWERS AT THIS TIME.
UPPER RIDGE BUILDS BACK ON MONDAY BEHIND THE SURFACE TROUGH AND IN
RESPONSE TO A WAVE MOVING ONTO THE NORTHWESTERN U.S. COAST. THIS
SHOULD SET THE STAGE FOR AN UNSEASONABLY WARM MONDAY WITH NEAR
RECORD HIGH TEMPERATURES OVER THE SOUTHWEST AND SOUTH CENTRAL.
RECORD HIGH FOR BISMARCK MONDAY IS 91 DEGREES...WITH A FORECAST HIGH
OF 89. OTHER FIRST ORDER STATION HIGHS ARE IN THE MID 90S AND WOULD
BE HARDER TO REACH.
THE UPPER RIDGE BREAKS DOWN MONDAY NIGHT AS THE NORTHWEST U.S.
TROUGH MOVES INTO THE NORTHERN ROCKIES AND A QUASI-ZONAL FLOW TAKES
SHAPE MONDAY NIGHT THROUGH THURSDAY. TEMPERATURES AFTER MONDAY WILL
RETURN TO NORMAL...AROUND 70 DEGREES FOR HIGHS. WITH A PROGRESSIVE
WESTERLY FLOW...PRECIPITATION CHANCES CANNOT BE RULED OUT OF
PRETTY MUCH ANY PERIOD FROM MONDAY NIGHT THROUGH THURSDAY. ALTHOUGH
ANY SHOWERS OR THUNDERSTORMS WOULD LIKELY BE SPOTTY. UTILIZED A
MODEL BLEND WITH PERSISTENCE FOR POPS WHICH PRETTY MUCH GIVES SLIGHT
CHANCE POPS THROUGH THE PERIOD. UNFORTUNATELY WITH MODEL TIMING AND
PLACEMENT DIFFERENCES IN THIS PROGRESSIVE FLOW ITS TOO HARD AT
THIS TIME TO TRY AND NAIL DOWN A SPECIFIC PERIOD FOR
PRECIPITATION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 105 PM CDT FRI MAY 10 2013
A STRONG COLD FRONT JUST NORTH OF KBIS WILL CONTINUE SOUTH AND
EXIT NORTH DAKOTA BY LATE AFTERNOON. STRONG NORTHWEST WINDS WITH
GUSTS OF 25-35 KTS ARE EXPECTED BEHIND THE FRONT. ISOLATED TO
SCATTERED SHOWER AND THUNDERSTORM ACTIVITY IS ALSO POSSIBLE NEAR
THE FRONT AT KDIK...KBIS AND KJMS.
&&
.FIRE WEATHER...
ISSUED AT 410 AM CDT FRI MAY 10 2013
THE FIRE WEATHER WATCH THAT WAS IN EFFECT FOR PORTIONS OF
NORTHWEST...NORTH CENTRAL...AND SOUTHWESTERN NORTH DAKOTA WILL BE
UPGRADED TO A RED FLAG WARNING. EXPECT DEWPOINTS TO RISE WITH THE
APPROACH OF THE COLD FRONT...THEN DROP INTO THE 20S BEHIND IT. WENT
WITH THESE LOWER DEWPOINTS THAN MODELS/GUIDANCE WOULD SUGGEST.
EXPECT THE SURFACE/BOUNDARY LAYER WILL MIX WELL UP TO H800 AND
LOWER DEWPOINTS THIS AFTERNOON. MINIMUM RELATIVE HUMIDITY VALUES
ARE EXPECTED TO BE AROUND 20 TO 25 PERCENT FOR MUCH OF WESTERN AND
PARTS OF CENTRAL NORTH DAKOTA. EXPECT AFTERNOON NORTHWEST WINDS OF
25 TO 30 MPH COMBINED WITH THE LOW RELATIVE HUMIDITY AND VERY DRY
PASTURES WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS. THESE
CONDITIONS WOULD SUPPORT RAPID FIRE SPREAD SHOULD A FIRE IGNITE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>003-009>011-017>019-021-031>033.
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>005-009>013-017>023-031>035-040>046.
&&
$$
UPDATE...AJ
SHORT TERM...JV
LONG TERM...TWH
AVIATION...AJ
FIRE WEATHER...JV
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1036 AM CDT FRI MAY 10 2013
.UPDATE...
ISSUED AT 1035 AM CDT FRI MAY 10 2013
THE MAIN IMPACTS FOR THE SHORT TERM UPDATE ARE GUSTY WINDS AND FIRE
DANGER.
A STRONG COLD FRONT CURRENTLY LOCATED NEAR MINOT WILL QUICKLY
BLAST SOUTH OUT OF NORTH DAKOTA BY LATE AFTERNOON. BEHIND THE
FRONT PRESSURE RISES NEAR 5 MB WITHIN THE LAST THREE HOURS WILL
DRIVE SUSTAINED WINDS NEAR 30 MPH AND FREQUENT GUSTS UP TO 45 MPH.
THEREFORE A WIND ADVISORY WAS ISSUED. THESE GUSTY WINDS AND VERY
DRY AIR WILL CONTINUE TO DRIVE DOWN RELATIVE HUMIDITIES AND FIRE
DANGER UP.
PRECIPITATION CHANCES WERE LOWERED FOR THIS UPDATE. LATEST GUIDANCE
FROM THE 13 UTC RAP AND 14 UTC HRRR SHOW VERY LITTLE PRECIPITATION
DEVELOPING ACROSS WESTERN AND CENTRAL NORTH DAKOTA THROUGH THE
AFTERNOON HOURS. LATEST OBSERVATIONS SHOW VERY DRY AIR AT THE
SURFACE AND ONLY LIGHT RAIN SHOWER ECHOS SHOWING UP ON RADAR. BEST
CHANCE OF PRECIPITATION STILL LOOKS TO BE ACROSS FAR SOUTHERN
NORTH DAKOTA LATE THIS AFTERNOON AS PEAK HEATING WILL INCREASE
INSTABILITY AND PROXIMITY TO A MORE MOIST AIRMASS MAY PROVIDE ENOUGH
TO SPAWN SOME SCATTERED SHOWERS AND THUNDERSTORMS.
UPDATE ISSUED AT 652 AM CDT FRI MAY 10 2013
COLD FRONT EXTENDING SOUTHWEST FROM A SURFACE LOW NEAR LAKE
WINNIPEG WILL MOVE INTO NORTHWEST NORTH DAKOTA SHORTLY. INCREASING
CLOUDS AND A FEW SHOWERS SHOWING UP OVER SOUTHERN SASKATCHEWAN AND
MANITOBA. CURRENT FORECAST HAS A GOOD HANDLE ON CURRENT PLACEMENT
OF CLOUDS AND PRECIPITATION. ONLY CHANGES TO THE FORECAST WERE TO
UPDATE CURRENT SENSIBLE WEATHER ELEMENTS. THIS DROPPED OUR
OVERNIGHT LOWS SOME ACROSS CENTRAL NORTH DAKOTA WHERE CLEAR SKIES
AND LIGHT WINDS ALLOWED TEMPERATURES TO DROP A BIT BELOW FORECAST.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 410 AM CDT FRI MAY 10 2013
MAIN HIGHLIGHT FOR THE SHORT TERM WILL BE THE APPROACHING COLD FRONT
AND RESULTING WEATHER IMPACTS INCLUDING FIRE WEATHER CONCERNS.
CURRENTLY...WATER VAPOR SATELLITE IMAGERY INDICATES UPPER LEVEL
SHORTWAVE OVER SOUTHERN MANITOBA/SASKATCHEWAN MOVING SOUTHEASTWARD.
THIS FEATURE HANDLED WELL BY THE MODELS AND WILL USE A MODEL BLEND
FOR FORECAST DETAILS. SURFACE COLD FRONT ASSOCIATED WITH THE UPPER
LEVEL SHORTWAVE EXTENDED FROM NORTHERN LAKE WINNIPEG ACROSS SOUTHERN
SASKATCHEWAN TO NORTH CENTRAL MONTANA. AHEAD OF THE FRONT WINDS WERE
LIGHT AND FROM THE SOUTH.
THE COLD FRONT IS PROGGED TO REACH THE NORTHWEST CORNER OF THE STATE
AROUND SUNRISE AND CONTINUE MOVING SOUTHEASTWARD. BY AROUND NOON CDT
THE FRONT SHOULD BE APPROACHING DICKINSON/GARRISON/DEVILS LAKE AREA
AND REACH THE JAMESTOWN AREA BY MID-LATE AFTERNOON. AHEAD OF THE
FRONT THE SOUTH WINDS SHOULD BECOME MORE SOUTHWESTERLY AND BEGIN
INCREASING...THEN AFTER THE FRONT PASSES WINDS SHOULD BECOME
NORTHWEST AND INCREASE TO 20 TO 30 MPH. BUFKIT SOUNDINGS AND LOOKING
AT H850 FORECAST WINDS...THERE SHOULD BE GOOD LINKAGE ALOFT TO ABOVE
H800 AND WINDS AROUND H850 ARE AROUND 30 KNOTS. THUS SUSTAINED WINDS
SHOULD BE JUST SHY OF WIND ADVISORY CRITERIA OF 30 MPH FOR 3 HOURS
OR MORE. WIND GUSTS COULD BE AS HIGH AS 35 TO POSSIBLY 40 MPH IN
SOME LOCALES.
THESE STRONG WINDS COMBINED WITH DRY GRASSLANDS WILL RAISE FIRE
WEATHER CONCERNS. SEE THE FIRE WEATHER SECTION BELOW FOR DETAILS.
THE COLD FRONT IS PROGGED TO EXTEND ACROSS SOUTHERN NORTH DAKOTA
THIS AFTERNOON - DURING PEAK HEATING OF THE DAY. CAPE VALUES ARE
200-400 FOR THE MID AND LATE AFTERNOON/EARLY EVENING HOURS AND WILL
KEEP THE CHANCE OF RAIN SHOWERS NORTHWEST AND NORTH CENTRAL NORTH
DAKOTA THIS MORNING AND THUNDERSHOWERS SOUTHWEST AND SOUTH CENTRAL
THIS AFTERNOON. LOOKING AT HIGH TEMPERATURES FROM THE 60S NORTH TO
THE LOW TO MID 70S SOUTH.
WINDS SHOULD DECREASE DURING THE EVENING WITH COOL AND DRY AIR
PUSHING INTO THE STATE. LOWS TONIGHT SHOULD DIP INTO THE 20S TO
LOWER 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 410 AM CDT FRI MAY 10 2013
WE BEGIN THE EXTENDED PERIOD ON THE COOL SIDE WITH CANADIAN HIGH
PRESSURE OVER THE REGION SATURDAY MORNING. STRONG UPPER LEVEL
RIDGING OVER THE WESTERN U.S. SATURDAY WILL TRANSLATE EAST THROUGH
THE WEEKEND BRINGING WARMER TEMPERATURES TO WESTERN NORTH DAKOTA ON
SUNDAY. DRY CONDITIONS ARE EXPECTED SATURDAY THROUGH SUNDAY.
A WEAK SURFACE TROUGH MOVES INTO THE AREA SUNDAY NIGHT...ASSOCIATED
WITH A NORTHERN STREAM WAVE THAT FLATTENS THE UPPER RIDGE THAT HAS
MOVED OVER THE NORTHERN PLAINS. MODELS ARE DEPICTING VERY LIGHT QPF
ALONG THE TROUGH BUT WITH ABUNDANT DRY AIR OVER THE REGION...WILL
HOLD OFF ON INTRODUCING A MENTION OF SHOWERS AT THIS TIME.
UPPER RIDGE BUILDS BACK ON MONDAY BEHIND THE SURFACE TROUGH AND IN
RESPONSE TO A WAVE MOVING ONTO THE NORTHWESTERN U.S. COAST. THIS
SHOULD SET THE STAGE FOR AN UNSEASONABLY WARM MONDAY WITH NEAR
RECORD HIGH TEMPERATURES OVER THE SOUTHWEST AND SOUTH CENTRAL.
RECORD HIGH FOR BISMARCK MONDAY IS 91 DEGREES...WITH A FORECAST HIGH
OF 89. OTHER FIRST ORDER STATION HIGHS ARE IN THE MID 90S AND WOULD
BE HARDER TO REACH.
THE UPPER RIDGE BREAKS DOWN MONDAY NIGHT AS THE NORTHWEST U.S.
TROUGH MOVES INTO THE NORTHERN ROCKIES AND A QUASI-ZONAL FLOW TAKES
SHAPE MONDAY NIGHT THROUGH THURSDAY. TEMPERATURES AFTER MONDAY WILL
RETURN TO NORMAL...AROUND 70 DEGREES FOR HIGHS. WITH A PROGRESSIVE
WESTERLY FLOW...PRECIPITATION CHANCES CANNOT BE RULED OUT OF
PRETTY MUCH ANY PERIOD FROM MONDAY NIGHT THROUGH THURSDAY. ALTHOUGH
ANY SHOWERS OR THUNDERSTORMS WOULD LIKELY BE SPOTTY. UTILIZED A
MODEL BLEND WITH PERSISTENCE FOR POPS WHICH PRETTY MUCH GIVES SLIGHT
CHANCE POPS THROUGH THE PERIOD. UNFORTUNATELY WITH MODEL TIMING AND
PLACEMENT DIFFERENCES IN THIS PROGRESSIVE FLOW ITS TOO HARD AT
THIS TIME TO TRY AND NAIL DOWN A SPECIFIC PERIOD FOR
PRECIPITATION.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 652 AM CDT FRI MAY 10 2013
A STRONG COLD FRONT HAS ENTERED NORTHWESTERN NORTH DAKOTA. THE
FRONT IS FORECAST TO MOVE THROUGH KISN...KMOT AND KDIK BETWEEN
15-18 UTC...KBIS BY 19-20 UTC AND KJMS BY 20-22 UTC. STRONG
NORTHWEST WINDS WITH GUSTS OF 35-45 KTS ARE EXPECTED BEHIND THE
FRONT. ISOLATED TO SCATTERED SHOWER AND THUNDERSTORM ACTIVITY IS
ALSO POSSIBLE NEAR THE FRONT AT KDIK...KBIS AND KJMS...WITH THE
TERMINAL MOST LIKELY TO BE IMPACTED BEING KJMS.
&&
.FIRE WEATHER...
ISSUED AT 410 AM CDT FRI MAY 10 2013
THE FIRE WEATHER WATCH THAT WAS IN EFFECT FOR PORTIONS OF
NORTHWEST...NORTH CENTRAL...AND SOUTHWESTERN NORTH DAKOTA WILL BE
UPGRADED TO A RED FLAG WARNING. EXPECT DEWPOINTS TO RISE WITH THE
APPROACH OF THE COLD FRONT...THEN DROP INTO THE 20S BEHIND IT. WENT
WITH THESE LOWER DEWPOINTS THAN MODELS/GUIDANCE WOULD SUGGEST.
EXPECT THE SURFACE/BOUNDARY LAYER WILL MIX WELL UP TO H800 AND
LOWER DEWPOINTS THIS AFTERNOON. MINIMUM RELATIVE HUMIDITY VALUES
ARE EXPECTED TO BE AROUND 20 TO 25 PERCENT FOR MUCH OF WESTERN AND
PARTS OF CENTRAL NORTH DAKOTA. EXPECT AFTERNOON NORTHWEST WINDS OF
25 TO 30 MPH COMBINED WITH THE LOW RELATIVE HUMIDITY AND VERY DRY
PASTURES WILL RESULT IN CRITICAL FIRE WEATHER CONDITIONS. THESE
CONDITIONS WOULD SUPPORT RAPID FIRE SPREAD SHOULD A FIRE IGNITE.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
RED FLAG WARNING UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>003-009>011-017>019-021-031>033.
WIND ADVISORY UNTIL 7 PM CDT /6 PM MDT/ THIS EVENING FOR
NDZ001>005-009>013-017>023-031>035-040>046.
&&
$$
UPDATE...AJ
SHORT TERM...JV
LONG TERM...TWH
AVIATION...JV
FIRE WEATHER...JV
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1115 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT CROSSING NORTHWEST OHIO WILL MOVE EAST OF THE AREA
TONIGHT. CHILLY HIGH PRESSURE FROM CENTRAL CANADA WILL BUILD OVER
THE REGION BY MONDAY. A WARM FRONT WILL DEVELOP OVER THE MIDWEST
ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
UPDATED FOR OVERNIGHT WORDING AND TIMING ADJUSTMENTS.
MID EVENING UPDATE...MOST OF THE WIND GUSTS HAVE BEEN HAVE BEEN
AROUND 30 KNOTS WITH THE FRONT. THIS IS IN LINE WITH THE CURRENT
FORECAST. EXPECT THE WIND TO DECREASE JUST A BIT AS THE FRONT
MOVES EAST ACROSS A MORE STABLE AIR MASS...BUT EVERYONE WILL STILL
LIKELY SEE GUSTS WITH THE FRONT AND FOR A COUPLE OF HOURS AFTER
THE FRONTAL PASSAGE. MADE SOME MINOR ADJUSTMENTS TO THE TIMING OF
THE LINE OF SHOWERS BASED ON THE CURRENT SPEED. GAVE EVERYONE A
"LIKELY" POP FOR AN HOUR OR TWO TONIGHT AS THE LINE OF SHOWERS
MOVES EAST ALTHOUGH IT MAY AMOUNT TO LITTLE MORE THAN A FEW
HUNDREDTHS OF AN INCH QPF. ALSO REFINED THE TEMP DROP WITH THE
FRONTAL PASSAGE. TEMPERATURES DROP PRETTY QUICKLY BACK INTO THE
40S.
TONIGHT DISCUSSION...THE COLD FRONT WILL WORK ITS WAY ACROSS THE
AREA THIS EVENING. THE TROUGH ALOFT IS SHARP AND THERE IS A LOT OF
MOMENTUM TO THE FRONT. THIS DESPITE COMING INTO AN AREA OF STABLE
AIR...THINK THERE IS A GOOD CHANCE OF A SHOWER IN MOST AREAS. DID
NOT MENTION THUNDER ALTHOUGH AN ISOLATED FLASH OF LIGHTNING NOT
OUT OF THE QUESTION. SOME OF THE SHOWERS WILL BE GUSTY...WITH A 35
KNOT LOW LEVEL NORTHWEST JET AND STRONG COLD ADVECTION FOLLOWING
THE FRONT AND A GOOD ISALLOBARIC PUSH. DRIER AIR AND SUBSIDENCE
WILL ALSO FOLLOW THE FRONTAL PASSAGE AND EXPECT CLEARING FROM WEST
TO EAST. LOWS WILL DROP INTO THE UPPER 30S MOST AREAS...LOWER/MID
40S NEAR LAKE ERIE. TAKE THE COAT IF YOU ARE GOING TO BE OUT LATER
TONIGHT OR EARLY SUNDAY MORNING.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
WITH COLD AIR ALOFT...STEEP LAPSE RATES WILL DEVELOP SUNDAY...
ESPECIALLY WITH A LITTLE MORNING SUNSHINE HEATING UP THE BOUNDARY
LAYER. CUMULUS WILL BUILD AND A FEW SHOWERS WILL DEVELOP... MAINLY
IN AND NEAR THE SNOWBELT OF NE OH/NW PA.
USED THE RAW GFS DATA FOR THE HIGHS SUNDAY...THE MOS GUIDANCE IS
STRONGLY BIASED BY CLIMATOLOGY THIS TIME OF YEAR. IT GAVE UPPER 40S
AND LOWER 50S...A FEW DEGREES BELOW GUIDANCE WHICH SEEMS REASONABLE.
A BRISK NORTHWEST WIND WILL COMPOUND THE CHILL. 850MB TEMPERATURES
WILL DROP TO -4 TO -6C.
THE CENTER OF THE SURFACE HIGH WILL STAY TO THE WEST SUNDAY NIGHT
AND IT WILL TAKE A WHILE FOR THE CUMULUS/STRATOCUMULUS TO DISSIPATE.
THE WIND WILL TAKE A WHILE TO SETTLE. NOT THE BEST CONDITIONS FOR
FROST OR RADIATIONAL COOLING. THAT BEING SAID...THE ACTUAL AIR
TEMPERATURES WILL DROP PRETTY CLOSE TO FREEZING EXCEPT NEAR THE LAKE
ERIE LAKE SHORE. WE PROBABLY WILL NOT SEE AN EXTENDED PERIOD OF
HOURS AT OR BELOW FREEZING AND WILL NOT ISSUE A FREEZE WATCH BUT WE
COULD JUST TOUCH FREEZING IN MANY SPOTS FOR LOWS. THINK THE BEST
APPROACH IS JUST TO KEEP FORECASTING FROST AND THEN ISSUE A FROST
ADVISORY WITH THE SUNDAY FORECAST FOR SUNDAY NIGHT. THE SNOWBELT AND
LAKESHORE WILL PROBABLY NOT SEE MUCH IN THE WAY OF FROST SUNDAY
NIGHT BUT IT COULD BE COLD ENOUGH FOR A FEW WET SNOW FLAKES TO MIX
WITH THE REMAINING SHOWERS.
THE RIDGE WILL BUILD IN ON MONDAY. FAIR WEATHER CUMULUS AND
STRATOCUMULUS AGAIN ARE LIKELY. HIGHS AGAIN BELOW NORMALS...IN THE
50S WITH SOME UPPER 40S EXTREME NE OH/NW PA. THE COLDEST LOWS ON
MONDAY NIGHT WILL SWITCH FROM NW OHIO TO EXTREME NE OH/NW PA. WILL
CONTINUE TO MENTION FROST FOR MONDAY NIGHT NE OH/NW PA.
SOME WARM ADVECTION CLOUDS ARE PROGGED TO SPREAD IN LATE MONDAY
NIGHT AND TUESDAY. A SPRINKLE OR BRIEF SHOWER CAN SOMETIMES OCCUR
WITH THESE DIFFERENTIAL ADVECTION SYSTEMS AND WILL HAVE A SLIGHT
CHANCE OF A SHOWER IN THE FORECAST TUESDAY. WILL AGAIN KEEP TEMPS A
LITTLE BELOW GUIDANCE TUESDAY...MOSTLY UPPER 50S AND LOWER 60S...
BASED ON THE INCREASING CLOUDS AND BIAS TO THE GUIDANCE THIS
TIME OF YEAR.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
MODELS ARE NOT QUITE IDENTICAL IN THEIR SOLUTIONS BUT THEY ARE BOTH
HINTING AT A WARM UP AS WE APPROACH THE MIDDLE OF NEXT WEEK. BROAD
UPPER LEVEL RIDGE IS PROGGED TO BUILD INTO THE FORECAST AREA BY MID
WEEK AND THEN FLATTEN TO BECOME ZONAL ACROSS THE ENTIRE UNITED
STATES BY THURSDAY. THIS SHOULD HELP BRING A BOOST OF WARMER AIR
INTO THE FORECAST AREA THAT WILL LAST RIGHT ON INTO THE END OF THE
WEEK AND WEEKEND. THERE IS NO INDICATION THAT ANY STRONG SURGES OF
COLD AIR WILL SLIDE SOUTH INTO THE FORECAST AREA DURING THIS PERIOD
AND LETS HOPE THIS IS THE LAST ONE.
ONE ISSUE WE WILL HAVE TO CONTEND WITH IS THE FACT THAT WITH THE
WARMER AIR AND HIGHER DEW POINTS...THE THREAT FOR PRECIPITATION WILL
INCREASE. THE OTHER FACTOR IS THE POTENTIAL FOR SOME KIND OF
BOUNDARY...WHETHER IT BE A STATIONARY FRONT OR WARM FRONT...WILL
LINGER AROUND THE REGION. THIS COULD VERY WELL BE THE FOCUSING
MECHANISM THAT COULD PRODUCE A CHANCE FOR SHOWERS AND THUNDERSTORMS
FOR EACH DAY DURING THE PERIOD.
DUE TO THE FACT THAT WE ARE IN MID MAY NOW AND THE SUN ANGLE IS
HIGH...THERE EXISTS THE POTENTIAL FOR TEMPERATURE BUSTS ON THE LOW
END THROUGH THIS PERIOD. WE COULD POSSIBLY SEE TEMPERATURES IN THE
80S EACH DAY RATHER THAN THE 70S FOR HIGHS. BUT...TO REMAIN
CONSISTENT AND COLLABORATED...WILL ERR ON THE SIDE OF LOWER END
UNTIL GET GET A BETTER FIX ON THE MODELS EXPECTED SOLUTION AFTER MID
WEEK.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
COLD FRONT NOW ENTERING NWRN OHIO AND BY 00Z SHOULD BE EAST OF
KTOL SO WILL START OUT KTOL AND KFDY IN POST FRONT NWLY FLOW AND
MVFR CIGS FOR A COUPLE HOURS AND THEN ALLOW CONDITIONS TO GO VFR.
BASED ON HRRR TIMING WILL BRING FRONT THROUGH KMFD AT 01Z AND KCLE
AT 0130Z. FRONT SHOULD REACH KYNG AROUND 03Z. EXPECT AN HOUR OR
TWO OF GUSTY WNW FLOW THEN DIURNAL DECREASE TO ABOUT 10KTS OR SO.
EXPECT VFR CIGS TO DEVELOP MOST LOCATIONS ON SUNDAY WITH POSSIBLY
SOME MVFR IN SCATTERED SHOWERS OFF THE LAKE EXTREME NERN OHIO AND
NWRN PA. SUNDAY SHOULD BE FAIRLY WINDY WITH WNW FLOW GUSTING 25 TO
30KTS.
.OUTLOOK...NON VFR POSSIBLE SUNDAY NIGHT AND MONDAY IN NE OH/NW
PA. ALSO POSSIBLE TUESDAY NIGHT.
&&
.MARINE...
COLD FRONT IS EXPECTED TO SWEEP EAST ACROSS THE LAKE THIS EVENING.
THIS FRONT WILL HAVE A BIT OF A PRESSURE WAVE WITH IT AND EXPECT
WINDS TO JUMP UP ALONG THE BOUNDARY. THE WINDS SHOULD DIMINISH A BIT
OVERNIGHT AND THEN PICK UP AGAIN AS MIXING TAKES PLACE DURING THE
DAY TOMORROW. WINDS COULD VERY WELL REACH 30 KNOTS ON THE LAKE AND
POTENTIALLY POKE INTO GALE FORCE TERRITORY FOR A SHORT PERIOD.
SO...FOR NOW WILL LEAVE GALE FORCE WINDS OUT OF THE FORECAST SINCE
THE DURATION SHOULD BE VERY SHORT. HOWEVER...WILL GO WITH A SMALL
CRAFT ADVISORY FOR LATER THIS AFTERNOON AND CONTINUE IT THROUGH
ABOUT MID DAY ON MONDAY. MAY NEED TO EXTEND IT FURTHER ON MONDAY FOR
THE EASTERN PORTIONS OF THE LAKE.
AS HIGH PRESSURE BUILDS EAST TOWARD THE AREA...A GRADUAL DECREASE IN
THE WINDS CAN BE EXPECTED FOR MONDAY INTO TUESDAY. HOWEVER...AS HIGH
PRESSURE MOVES EAST OF THE LAKE...WINDS WILL BEGIN TO PICK BACK UP
AGAIN OUT OF THE SOUTH TO SOUTHWEST WEDNESDAY AND THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT MONDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...TK/KOSARIK
SHORT TERM...KOSARIK
LONG TERM...LOMBARDY
AVIATION...TK
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
910 PM EDT SAT MAY 11 2013
.SYNOPSIS...
A COLD FRONT CROSSING NORTHWEST OHIO WILL MOVE EAST OF THE AREA
TONIGHT. CHILLY HIGH PRESSURE FROM CENTRAL CANADA WILL BUILD OVER
THE REGION BY MONDAY. A WARM FRONT WILL DEVELOP OVER THE MIDWEST
ON TUESDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
MID EVENING UPDATE...MOST OF THE WIND GUSTS HAVE BEEN HAVE BEEN
AROUND 30 KNOTS WITH THE FRONT. THIS IS IN LINE WITH THE CURRENT
FORECAST. EXPECT THE WIND TO DECREASE JUST A BIT AS THE FRONT
MOVES EAST ACROSS A MORE STABLE AIR MASS...BUT EVERYONE WILL STILL
LIKELY SEE GUSTS WITH THE FRONT AND FOR A COUPLE OF HOURS AFTER
THE FRONTAL PASSAGE. MADE SOME MINOR ADJUSTMENTS TO THE TIMING OF
THE LINE OF SHOWERS BASED ON THE CURRENT SPEED. GAVE EVERYONE A
"LIKELY" POP FOR AN HOUR OR TWO TONIGHT AS THE LINE OF SHOWERS
MOVES EAST ALTHOUGH IT MAY AMOUNT TO LITTLE MORE THAN A FEW
HUNDREDTHS OF AN INCH QPF. ALSO REFINED THE TEMP DROP WITH THE
FRONTAL PASSAGE. TEMPERATURES DROP PRETTY QUICKLY BACK INTO THE
40S.
TONIGHT DISCUSSION...THE COLD FRONT WILL WORK ITS WAY ACROSS THE
AREA THIS EVENING. THE TROUGH ALOFT IS SHARP AND THERE IS A LOT OF
MOMENTUM TO THE FRONT. THIS DESPITE COMING INTO AN AREA OF STABLE
AIR...THINK THERE IS A GOOD CHANCE OF A SHOWER IN MOST AREAS. DID
NOT MENTION THUNDER ALTHOUGH AN ISOLATED FLASH OF LIGHTNING NOT
OUT OF THE QUESTION. SOME OF THE SHOWERS WILL BE GUSTY...WITH A 35
KNOT LOW LEVEL NORTHWEST JET AND STRONG COLD ADVECTION FOLLOWING
THE FRONT AND A GOOD ISALLOBARIC PUSH. DRIER AIR AND SUBSIDENCE
WILL ALSO FOLLOW THE FRONTAL PASSAGE AND EXPECT CLEARING FROM WEST
TO EAST. LOWS WILL DROP INTO THE UPPER 30S MOST AREAS...LOWER/MID
40S NEAR LAKE ERIE. TAKE THE COAT IF YOU ARE GOING TO BE OUT LATER
TONIGHT OR EARLY SUNDAY MORNING.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY NIGHT/...
WITH COLD AIR ALOFT...STEEP LAPSE RATES WILL DEVELOP SUNDAY...
ESPECIALLY WITH A LITTLE MORNING SUNSHINE HEATING UP THE BOUNDARY
LAYER. CUMULUS WILL BUILD AND A FEW SHOWERS WILL DEVELOP... MAINLY
IN AND NEAR THE SNOWBELT OF NE OH/NW PA.
USED THE RAW GFS DATA FOR THE HIGHS SUNDAY...THE MOS GUIDANCE IS
STRONGLY BIASED BY CLIMATOLOGY THIS TIME OF YEAR. IT GAVE UPPER 40S
AND LOWER 50S...A FEW DEGREES BELOW GUIDANCE WHICH SEEMS REASONABLE.
A BRISK NORTHWEST WIND WILL COMPOUND THE CHILL. 850MB TEMPERATURES
WILL DROP TO -4 TO -6C.
THE CENTER OF THE SURFACE HIGH WILL STAY TO THE WEST SUNDAY NIGHT
AND IT WILL TAKE A WHILE FOR THE CUMULUS/STRATOCUMULUS TO DISSIPATE.
THE WIND WILL TAKE A WHILE TO SETTLE. NOT THE BEST CONDITIONS FOR
FROST OR RADIATIONAL COOLING. THAT BEING SAID...THE ACTUAL AIR
TEMPERATURES WILL DROP PRETTY CLOSE TO FREEZING EXCEPT NEAR THE LAKE
ERIE LAKE SHORE. WE PROBABLY WILL NOT SEE AN EXTENDED PERIOD OF
HOURS AT OR BELOW FREEZING AND WILL NOT ISSUE A FREEZE WATCH BUT WE
COULD JUST TOUCH FREEZING IN MANY SPOTS FOR LOWS. THINK THE BEST
APPROACH IS JUST TO KEEP FORECASTING FROST AND THEN ISSUE A FROST
ADVISORY WITH THE SUNDAY FORECAST FOR SUNDAY NIGHT. THE SNOWBELT AND
LAKESHORE WILL PROBABLY NOT SEE MUCH IN THE WAY OF FROST SUNDAY
NIGHT BUT IT COULD BE COLD ENOUGH FOR A FEW WET SNOW FLAKES TO MIX
WITH THE REMAINING SHOWERS.
THE RIDGE WILL BUILD IN ON MONDAY. FAIR WEATHER CUMULUS AND
STRATOCUMULUS AGAIN ARE LIKELY. HIGHS AGAIN BELOW NORMALS...IN THE
50S WITH SOME UPPER 40S EXTREME NE OH/NW PA. THE COLDEST LOWS ON
MONDAY NIGHT WILL SWITCH FROM NW OHIO TO EXTREME NE OH/NW PA. WILL
CONTINUE TO MENTION FROST FOR MONDAY NIGHT NE OH/NW PA.
SOME WARM ADVECTION CLOUDS ARE PROGGED TO SPREAD IN LATE MONDAY
NIGHT AND TUESDAY. A SPRINKLE OR BRIEF SHOWER CAN SOMETIMES OCCUR
WITH THESE DIFFERENTIAL ADVECTION SYSTEMS AND WILL HAVE A SLIGHT
CHANCE OF A SHOWER IN THE FORECAST TUESDAY. WILL AGAIN KEEP TEMPS A
LITTLE BELOW GUIDANCE TUESDAY...MOSTLY UPPER 50S AND LOWER 60S...
BASED ON THE INCREASING CLOUDS AND BIAS TO THE GUIDANCE THIS
TIME OF YEAR.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
MODELS ARE NOT QUITE IDENTICAL IN THEIR SOLUTIONS BUT THEY ARE BOTH
HINTING AT A WARM UP AS WE APPROACH THE MIDDLE OF NEXT WEEK. BROAD
UPPER LEVEL RIDGE IS PROGGED TO BUILD INTO THE FORECAST AREA BY MID
WEEK AND THEN FLATTEN TO BECOME ZONAL ACROSS THE ENTIRE UNITED
STATES BY THURSDAY. THIS SHOULD HELP BRING A BOOST OF WARMER AIR
INTO THE FORECAST AREA THAT WILL LAST RIGHT ON INTO THE END OF THE
WEEK AND WEEKEND. THERE IS NO INDICATION THAT ANY STRONG SURGES OF
COLD AIR WILL SLIDE SOUTH INTO THE FORECAST AREA DURING THIS PERIOD
AND LETS HOPE THIS IS THE LAST ONE.
ONE ISSUE WE WILL HAVE TO CONTEND WITH IS THE FACT THAT WITH THE
WARMER AIR AND HIGHER DEW POINTS...THE THREAT FOR PRECIPITATION WILL
INCREASE. THE OTHER FACTOR IS THE POTENTIAL FOR SOME KIND OF
BOUNDARY...WHETHER IT BE A STATIONARY FRONT OR WARM FRONT...WILL
LINGER AROUND THE REGION. THIS COULD VERY WELL BE THE FOCUSING
MECHANISM THAT COULD PRODUCE A CHANCE FOR SHOWERS AND THUNDERSTORMS
FOR EACH DAY DURING THE PERIOD.
DUE TO THE FACT THAT WE ARE IN MID MAY NOW AND THE SUN ANGLE IS
HIGH...THERE EXISTS THE POTENTIAL FOR TEMPERATURE BUSTS ON THE LOW
END THROUGH THIS PERIOD. WE COULD POSSIBLY SEE TEMPERATURES IN THE
80S EACH DAY RATHER THAN THE 70S FOR HIGHS. BUT...TO REMAIN
CONSISTENT AND COLLABORATED...WILL ERR ON THE SIDE OF LOWER END
UNTIL GET GET A BETTER FIX ON THE MODELS EXPECTED SOLUTION AFTER MID
WEEK.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
COLD FRONT NOW ENTERING NWRN OHIO AND BY 00Z SHOULD BE EAST OF
KTOL SO WILL START OUT KTOL AND KFDY IN POST FRONT NWLY FLOW AND
MVFR CIGS FOR A COUPLE HOURS AND THEN ALLOW CONDITIONS TO GO VFR.
BASED ON HRRR TIMING WILL BRING FRONT THROUGH KMFD AT 01Z AND KCLE
AT 0130Z. FRONT SHOULD REACH KYNG AROUND 03Z. EXPECT AN HOUR OR
TWO OF GUSTY WNW FLOW THEN DIURNAL DECREASE TO ABOUT 10KTS OR SO.
EXPECT VFR CIGS TO DEVELOP MOST LOCATIONS ON SUNDAY WITH POSSIBLY
SOME MVFR IN SCATTERED SHOWERS OFF THE LAKE EXTREME NERN OHIO AND
NWRN PA. SUNDAY SHOULD BE FAIRLY WINDY WITH WNW FLOW GUSTING 25 TO
30KTS.
.OUTLOOK...NON VFR POSSIBLE SUNDAY NIGHT AND MONDAY IN NE OH/NW
PA. ALSO POSSIBLE TUESDAY NIGHT.
&&
.MARINE...
COLD FRONT IS EXPECTED TO SWEEP EAST ACROSS THE LAKE THIS EVENING.
THIS FRONT WILL HAVE A BIT OF A PRESSURE WAVE WITH IT AND EXPECT
WINDS TO JUMP UP ALONG THE BOUNDARY. THE WINDS SHOULD DIMINISH A BIT
OVERNIGHT AND THEN PICK UP AGAIN AS MIXING TAKES PLACE DURING THE
DAY TOMORROW. WINDS COULD VERY WELL REACH 30 KNOTS ON THE LAKE AND
POTENTIALLY POKE INTO GALE FORCE TERRITORY FOR A SHORT PERIOD.
SO...FOR NOW WILL LEAVE GALE FORCE WINDS OUT OF THE FORECAST SINCE
THE DURATION SHOULD BE VERY SHORT. HOWEVER...WILL GO WITH A SMALL
CRAFT ADVISORY FOR LATER THIS AFTERNOON AND CONTINUE IT THROUGH
ABOUT MID DAY ON MONDAY. MAY NEED TO EXTEND IT FURTHER ON MONDAY FOR
THE EASTERN PORTIONS OF THE LAKE.
AS HIGH PRESSURE BUILDS EAST TOWARD THE AREA...A GRADUAL DECREASE IN
THE WINDS CAN BE EXPECTED FOR MONDAY INTO TUESDAY. HOWEVER...AS HIGH
PRESSURE MOVES EAST OF THE LAKE...WINDS WILL BEGIN TO PICK BACK UP
AGAIN OUT OF THE SOUTH TO SOUTHWEST WEDNESDAY AND THURSDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT MONDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...KOSARIK
NEAR TERM...KOSARIK
SHORT TERM...KOSARIK
LONG TERM...LOMBARDY
AVIATION...TK
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS PENDLETON OR
817 PM PDT SAT MAY 11 2013
.UPDATE...THE UPPER LEVEL HIGH PRESSURE RIDGE THAT HAS BROUGHT
UNSEASONABLY HOT CONDITIONS FOR SEVERAL DAYS IS SHIFTING
EASTWARD...AND THE UPPER FLOW IS BACKING TO THE SOUTHWEST. HIGH
LEVEL CLOUDS HAVE SPREAD THROUGHOUT WA/OR WHICH WILL KEEP
OVERNIGHT LOWS VERY MILD. LOW TEMPERATURES MAY NEED TO BE
INCREASED IN SEVERAL ZONES. FORECAST WAS UPDATED TO REMOVE
THUNDERSTORMS THIS EVENING EXCEPT IN THE HIGHER TERRAIN...BUT
THERE IS NO INDICATION OF ANY CONVECTIVE ACTIVITY SO WILL REMOVE
ALTOGETHER FOR THIS EVENING. HOWEVER...THERE WILL BE ELEVATED
INSTABILITY OVERNIGHT...AND THE HRRR AND OTHER RAP INSTABILITY
PARAMETERS HAVE HINTED ON SOME CONVECTIVE PRECIPITATION MOVING
ACROSS THE AREA. BASED ON PREVIOUS HRRR RUNS...I ADDED A SLIGHT
CHANCE OF THUNDERSTORMS OVERNIGHT TO CENTRAL AND NORTH CENTRAL
OREGON AND SPRINKLES TO THE LOWER COLUMBIA BASIN AND BLUE MOUNTAIN
FOOTHILLS EARLY SUNDAY MORNING. IT COULD BE ALTOCUMULUS
CASTELLANUS CLOUDS...BUT WILL NOT RULE OUT SOME VERY LIGHT
PRECIPITATION OR A HIGH BASED THUNDERSTORM OR TWO. THE LATEST HRRR
IS FARTHER WEST WITH THE SMALL BAND OF CONVECTIVE PCPN...BUT WILL
KEEP WHERE THE ELEVATED INSTABILITY IS GREATEST. WISTER
&&
.AVIATION...00Z TAFS (PREVIOUS DISCUSSION)...VFR CONDITIONS WILL
CONTINUE FOR THE NEXT 24 HOURS. A FEW THUNDERSTORMS WILL BE
POSSIBLE FROM CENTRAL OREGON THROUGH THE NORTHEAST MOUNTAINS
THROUGH 03Z...AFFECTING KBDN AND KRDM. WINDS WILL GENERALLY REMAIN
BELOW 15 KTS THOUGH KDLS WILL HAVE GUSTS TO 25 KTS THIS AFTERNOON
THROUGH 03Z. WIND WILL DECREASE TO DIURNAL DRAINAGE OVERNIGHT AND
BECOME SOUTHWEST TO 10 TO 20 KTS ACROSS THE REGION BY SUNDAY
AFTERNOON WITH A FEW THUNDERSTORMS AGAIN FROM CENTRAL OREGON
THROUGH NORTHEAST OREGON. ML
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 59 80 53 69 / 10 20 30 40
ALW 63 82 57 72 / 10 20 30 40
PSC 61 85 57 74 / 10 20 20 30
YKM 60 81 52 72 / 10 20 20 30
HRI 58 82 55 74 / 0 20 20 30
ELN 59 76 51 68 / 10 30 20 30
RDM 55 81 48 67 / 20 20 20 20
LGD 52 80 50 70 / 10 30 30 40
GCD 51 81 50 71 / 10 30 30 40
DLS 60 76 53 69 / 10 40 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SUNDAY : GREEN
MONDAY : YELLOW
TUESDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
85
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
531 PM EDT FRI MAY 10 2013
.SYNOPSIS...
SOUTHWEST FLOW AND MOISTURE WILL INCREASE TODAY THROUGH TONIGHT
AHEAD OF AN APPROACHING COLD FRONT. MOISTURE AND INSTABILITY WILL
LINGER THROUGH SATURDAY AS A SECOND REINFORCING FRONT APPROACHES
FROM THE NORTHWEST. THIS FRONT WILL CROSS THE REGION SUNDAY MORNING
AND USHER IN A DRIER AIRMASS ALONG WITH MUCH COOLER TEMPERATURES.
COOL HIGH PRESSURE WILL LINGER MONDAY THROUGH TUESDAY...WITH
TEMPERATURES REBOUNDING MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
2130 UTC UPDATE...POPS HAVE BEEN ADJUSTED PER SATELLITE
IMAGERY...WITH INCREASES NEAR KGSP AND KGMU...AND LOWER VALUES
ELSEWHERE.
AS OF 200 PM...A PRE-FRONTAL SHORTWAVE TROF...ASSOCIATED WITH A PAIR
OF MCV/S WILL CROSS THE CWFA THIS EVENING. THE ENVIRONMENT IS FAIRLY
UNSTABLE...WITH SBCAPES IN THE 1000-1500 J/KG...HIGHEST ACRS THE
UPSTATE AND NE GA. DIFFERENTIAL HEATING IN THE MTNS AND ALONG EDGE
OF THE THICKER CIRRUS SHIELD IS HELPING TO INITIATE SCATTERED SHWR
COVERAGE ALREADY EARLY THIS AFTN. THE 16Z HRRR SEEMS TO HAVE THE
CLOSEST IDEA OF THE ACTIVITY COVERAGE...AND IT TAKES IT EWD ACRS THE
CWFA THRU THE REST OF THE AFTN...BRINGING IN THE MORE STABLE MCV AIR
IN FROM THE WEST. THE ENVIRONMENT STILL DOES NOT LOOK ALL THAT
IMPRESSIVE FROM A SEVERE THREAT STANDPOINT. SO WILL CONTINUE TO ONLY
MENTION LGTNG/HVY RAIN IN HWO. AS FOR HYDRO/HVY RAIN THREAT...WITH
THE MOVEMENT OF THE SHORTWAVE AND OVERALL CONVECTION...THINK ANY
AREAS RECEIVING AN INCH OR MORE WITH ONE STORM IS STILL FAIRLY LOW.
MOST AREAS PROBABLY WILL RECEIVE LESS THAN A QUARTER INCH THRU
TONIGHT.
AS COLD FRONT APPROACHES FROM THE WEST...PROFILES ACRS THE CWFA
REMAIN MOIST...WITH PERSISTENT DEEP LAYER WEAK-MOD Q-VECTOR
CONVERGENCE. CONVECTION ALLOWING MODELS DO SHOW MAINLY DEBRIS SHWRS
WITH POTENTIALLY A FEW RUMBLES OF THUNDER OVERNIGHT. THE MAIN
LIMITING FACTOR TO MORE ROBUST CONVECTION/HEAVY RAIN WILL BE ONGOING
CONVECTION ALONG THE GULF COAST...WHICH WILL ROB THE SRN
APPALACHIANS OF THE HIGHER PWAT AIR. WILL CONTINUE WITH 30-40 POP IN
THE PIEDMONT AND 50-60 IN THE MTNS. TEMPS WILL BE ABOVE NORMAL IN
THE MOIST PRE-FRONTAL AIR MASS.
SATURDAY...COLD FRONT AND ASSOCIATED MID LVL SHORTWAVE TROF WILL
CROSS THE AREA DURING THE DAY. LLVL FLOW VEERS TO NEARLY DUE
WESTERLY AHEAD OF THE SFC BNDRY...WITH PWATS DROPPING. WILL CONTINUE
WITH LIKELY POPS IN THE NC ZONES...AND HIGH-END CHC SOUTH. SEVERE
THREAT LOOKS TO STAY EAST WHERE BETTER SHEAR AND INSTBY WILL SET UP.
QPF STILL LOOKS TO BE LIMITED...AS STORMS SHUD HAVE DECENT EWD
MOTION...AND DRY AIR BEGINS TO FILTER IN. TEMPS ARE EXPECTED TO
REACH THE 70S BELOW 3500 FT...TO LWR 80S IN THE LWR PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 145 PM EDT FRIDAY...A STRONG UPPER LOW WILL MOVE ACROSS THE
GREAT LAKES STATES SATURDAY NIGHT AND SUNDAY. THIS WILL PUSH A COLD
FRONT ACROSS THE REGION EARLY ON SUNDAY. SATURDAY NIGHT THE UPPER
LEVEL FLOW WILL BACK JUST A BIT AHEAD OF THE ADVANCING UPPER
LOW...THOUGH THE LLVL FLOW WILL REMAIN OUT OF THE WEST TO NORTHWEST.
INSTABILITY WILL BE QUITE LIMITED AFTER MID-EVENING...AND WHILE
THERE WILL BE SOME FORCING FOR SHOWERS AND TSTMS OVER THE EASTERN
ZONES...THE THREAT OF SEVERE WEATHER WILL BE MINIMAL.
BY SUNDAY MORNING A BAND OF LOW TOPPED SHOWERS MAY MOVE INTO THE
MOUNTAINS ALONG THE TRUE COLD FRONT. ANY MEASURE RAINFALL WITH THESE
SHOWERS SHOULD BE CONFINED TO THE IMMEDIATE TENNESSEE BORDER.
SUNDAY WILL BE PLEASANTLY MILD. IT WILL BE BREEZY ACROSS THE
MOUNTAINS AS SKIES CLEAR. AS COOL HIGH PRESSURE BUILDS IN FOR SUNDAY
NIGHT...SOME INTERIOR VALLEYS MAY SEE AREAS OF FROST. AND CERTAIN
HIGH ELEVATIONS COULD EXPERIENCE AN ADVECTIVE FROST. WITH HIGH
PRESSURE STILL BUILDING INTO THE REGION...THERE SHOULD STILL BE
ENOUGH OF FLOW THROUGH THE MAJOR VALLEYS TO KEEP FROST FROM FORMING.
OVERALL...CONFIDENCE IS GOOD THAT SHELTERED VALLEYS WILL SEE SOME
FROST...THOUGH I/M NOT CERTAIN HOW WIDESPREAD IT WILL BE AT THIS
POINT. WE WILL CONTINUE TO MENTION THIS POSSIBILITY IN THE HWO.
MONDAY WILL BE SUNNY AND PLEASANT WITH MAX TEMPS RUNNING ABOUT 10
DEGREES BELOW NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...THE GLOBAL MODELS CONTINUE TO AGREE THAT
THE SHARP UPPER TROUGH AXIS WILL MOVE OFFSHORE MON NIGHT FOLLOWED BY
UPPER RIDGING TUE/WED. THE UPPER RIDGE AXIS WILL CROSS THE FORECAST
AREA WED NIGHT AND THE UPPER PATTERN BECOMES SWLY BY THU WITH A LOW
AMPLITUDE UPPER TROUGH APPROACHING FROM THE WEST. THE TROUGH AXIS
WILL THEN CROSS THE REGION ON FRI.
AT THE SURFACE...COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN
MON NIGHT AND SETTLES OVER THE REGION TUE. TEMPS ON MON NIGHT SHOULD
RUN 10-15 DEGREES BELOW NORMAL WITH FROST/FREEZE POSSIBLE OVER THE
NC MOUNTAINS/VALLEYS. MAX TEMPS ON TUE WILL REBOUND 2 TO 3 DEGREES
BUT STILL LIKELY REMAIN 5-10 DEGREES BELOW NORMAL. TEMPS QUICKLY
WARM UP TO NEAR NORMAL BY WED AFTERNOON AS THE CENTER OF HIGH
PRESSURE MOVES OFFSHORE AND RETURN SWLY FLOW DEVELOPS OVER THE
REGION. THE HIGH WILL REMAIN CENTERED OFF THE ATLANTIC COAST THU
WITH ITS SURFACE RIDGE EXTENDING INTO THE CWA. CONDITIONS LOOK DRY
THROUGH WED AND I/VE MENTIONED 20/30 PERCENT POPS FOR THUNDERSTORMS
LATE THURSDAY...MAINLY IN THE MOUNTAINS DUE TO INCREASING
MOISTURE/BUOYANCY. A SURFACE COLD FRONT WILL APPROACH THE SOUTHERN
APPALACHIANS BY THU NIGHT AND TRAVERS THE FORECAST AREA ON FRI.
HOWEVER...MODELS INDICATE THAT THE FRONT WILL WEAKEN AS IT MOVES
ACROSS REGION. THEREFORE...I HAVE KEPT POPS IN THE 20 TO 30 PERCENT
RANGE ON FRI. TEMPS WILL REMAIN A FEW DEGREES ABOVE NORMAL THU/FRI.
&&
.AVIATION /22Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A THIN BKN-OVC CIRRUS LAYER HAS STREAMED INTO THE AREA
FROM THE WEST...BUT IS NOT ENUF TO INHIBIT CONVECTIVE CUMULUS TO
DEVELOP TO THE WEST OF THE TERMINAL. SCATTERED SHRA AND A FEW TSRA
ARE EXPECTED TO DEVELOP ACRS THE AREA DURING THE AFTN HOURS. FOR
NOW...WILL GO WITH A TEMPO SHRA DURING THE PEAK HEATING HOURS...AS
TS CHCS TOO LOW ATTM. MAY NEED TO ADD IN TS MENTION...POSSIBLY AS A
TEMPO GROUP WITH A LATER AMD...IF COVERAGE ENDS UP GREATER THAN
EXPECTED. OTHERWISE...SW WINDS ARE GENERALLY 10-15 KTS WITH GUSTS
NEAR 20 KTS. THEY SHUD DIMINISH AROUND SUNSET SLIGHTLY AND LOSE THE
GUSTINESS. THERE WILL BE PLENTY OF MID AND UPR LVL MOISTURE
LINGERING OVERNIGHT...WITH SOME SHRA/TSRA POSSIBLE...ESP IN THE
09Z-12Z TIME FRAME. NOT CONFIDENT ENUF ON TS TO HAVE PROB30
THERE...BUT STILL EXPECT ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY
MORNING...WHICH WARRANTS A PROB30 AFTER 13Z. GUIDANCE NOT INDICATING
ANY RESTRICTIONS...BUT SOME FOG/STRATUS IS POSSIBLE LATE TNGT IF
THERE IS MORE RAINFALL THAN EXPECTED THIS AFTN/EVE.
ELSEWHERE...SCATTERED SHRA HAVE ALREADY DEVELOPED BEFORE THE 18Z TAF
ISSUANCE TO THE WEST OF A KAVL/KGMU/KAND LINE. THIS ACTIVITY IS
EXPECTED TO INCREASE IN COVERAGE AND SPREAD ACRS THE TAF SITES THIS
AFTN THRU ABOUT SUNSET. THE SCATTERED NATURE OF THE ACTIVITY SEEMS
TO WARRANT JUST VCTS MENTIONS FOR NOW. THERE WILL BE PLENTY OF MID
AND UPR LVL MOISTURE LINGERING OVERNIGHT...WITH SOME SHRA/TSRA
POSSIBLE. OVERALL...NOT EXPECTING MUCH FOG/STRATUS
POTENTIAL...EXCEPT IF A SITE IS HIT DIRECTLY BY A SHRA. STILL EXPECT
ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY MORNING...WHICH WARRANTS A
PROB30 AFTER DAYBREAK AT ALL SITES.
OUTLOOK...THE FIRST OF TWO COLD FRONT WILL SWEEP ACROSS THE REGION
ON SATURDAY. THE SECOND COLD FRONT WILL PASS EARLY SUNDAY. SHOWERS
AND THUNDERSTORMS WILL DEVELOP AHEAD OF THESE FRONTS...ESPECIALLY
SATURDAY. DRY WEATHER WILL BEGIN ON MONDAY.
CONFIDENCE TABLE...
21-03Z 03-09Z 09-15Z 15-21Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...JOH
AVIATION...ARK/JAT
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
344 PM EDT FRI MAY 10 2013
.SYNOPSIS...
SOUTHWEST FLOW AND MOISTURE WILL INCREASE TODAY THROUGH TONIGHT
AHEAD OF AN APPROACHING COLD FRONT. MOISTURE AND INSTABILITY WILL
LINGER THROUGH SATURDAY AS A SECOND REINFORCING FRONT APPROACHES
FROM THE NORTHWEST. THIS FRONT WILL CROSS THE REGION SUNDAY MORNING
AND USHER IN A DRIER AIRMASS ALONG WITH MUCH COOLER TEMPERATURES.
COOL HIGH PRESSURE WILL LINGER MONDAY THROUGH TUESDAY...WITH
TEMPERATURES REBOUNDING MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
1945 UTC UPDATE...POPS HAVE BEEN RAISED IN THE NORTHERN AND SOUTHERN
NC MOUNTAINS PER RADAR TRENDS. SKY COVER WAS UPDATED FROM VISIBLE
SATELLITE IMAGERY.
AS OF 200 PM...A PRE-FRONTAL SHORTWAVE TROF...ASSOCIATED WITH A PAIR
OF MCV/S WILL CROSS THE CWFA THIS EVENING. THE ENVIRONMENT IS FAIRLY
UNSTABLE...WITH SBCAPES IN THE 1000-1500 J/KG...HIGHEST ACRS THE
UPSTATE AND NE GA. DIFFERENTIAL HEATING IN THE MTNS AND ALONG EDGE
OF THE THICKER CIRRUS SHIELD IS HELPING TO INITIATE SCATTERED SHWR
COVERAGE ALREADY EARLY THIS AFTN. THE 16Z HRRR SEEMS TO HAVE THE
CLOSEST IDEA OF THE ACTIVITY COVERAGE...AND IT TAKES IT EWD ACRS THE
CWFA THRU THE REST OF THE AFTN...BRINGING IN THE MORE STABLE MCV AIR
IN FROM THE WEST. THE ENVIRONMENT STILL DOES NOT LOOK ALL THAT
IMPRESSIVE FROM A SEVERE THREAT STANDPOINT. SO WILL CONTINUE TO ONLY
MENTION LGTNG/HVY RAIN IN HWO. AS FOR HYDRO/HVY RAIN THREAT...WITH
THE MOVEMENT OF THE SHORTWAVE AND OVERALL CONVECTION...THINK ANY
AREAS RECEIVING AN INCH OR MORE WITH ONE STORM IS STILL FAIRLY LOW.
MOST AREAS PROBABLY WILL RECEIVE LESS THAN A QUARTER INCH THRU
TONIGHT.
AS COLD FRONT APPROACHES FROM THE WEST...PROFILES ACRS THE CWFA
REMAIN MOIST...WITH PERSISTENT DEEP LAYER WEAK-MOD Q-VECTOR
CONVERGENCE. CONVECTION ALLOWING MODELS DO SHOW MAINLY DEBRIS SHWRS
WITH POTENTIALLY A FEW RUMBLES OF THUNDER OVERNIGHT. THE MAIN
LIMITING FACTOR TO MORE ROBUST CONVECTION/HEAVY RAIN WILL BE ONGOING
CONVECTION ALONG THE GULF COAST...WHICH WILL ROB THE SRN
APPALACHIANS OF THE HIGHER PWAT AIR. WILL CONTINUE WITH 30-40 POP IN
THE PIEDMONT AND 50-60 IN THE MTNS. TEMPS WILL BE ABOVE NORMAL IN
THE MOIST PRE-FRONTAL AIR MASS.
SATURDAY...COLD FRONT AND ASSOCIATED MID LVL SHORTWAVE TROF WILL
CROSS THE AREA DURING THE DAY. LLVL FLOW VEERS TO NEARLY DUE
WESTERLY AHEAD OF THE SFC BNDRY...WITH PWATS DROPPING. WILL CONTINUE
WITH LIKELY POPS IN THE NC ZONES...AND HIGH-END CHC SOUTH. SEVERE
THREAT LOOKS TO STAY EAST WHERE BETTER SHEAR AND INSTBY WILL SET UP.
QPF STILL LOOKS TO BE LIMITED...AS STORMS SHUD HAVE DECENT EWD
MOTION...AND DRY AIR BEGINS TO FILTER IN. TEMPS ARE EXPECTED TO
REACH THE 70S BELOW 3500 FT...TO LWR 80S IN THE LWR PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 145 PM EDT FRIDAY...A STRONG UPPER LOW WILL MOVE ACROSS THE
GREAT LAKES STATES SATURDAY NIGHT AND SUNDAY. THIS WILL PUSH A COLD
FRONT ACROSS THE REGION EARLY ON SUNDAY. SATURDAY NIGHT THE UPPER
LEVEL FLOW WILL BACK JUST A BIT AHEAD OF THE ADVANCING UPPER
LOW...THOUGH THE LLVL FLOW WILL REMAIN OUT OF THE WEST TO NORTHWEST.
INSTABILITY WILL BE QUITE LIMITED AFTER MID-EVENING...AND WHILE
THERE WILL BE SOME FORCING FOR SHOWERS AND TSTMS OVER THE EASTERN
ZONES...THE THREAT OF SEVERE WEATHER WILL BE MINIMAL.
BY SUNDAY MORNING A BAND OF LOW TOPPED SHOWERS MAY MOVE INTO THE
MOUNTAINS ALONG THE TRUE COLD FRONT. ANY MEASURE RAINFALL WITH THESE
SHOWERS SHOULD BE CONFINED TO THE IMMEDIATE TENNESSEE BORDER.
SUNDAY WILL BE PLEASANTLY MILD. IT WILL BE BREEZY ACROSS THE
MOUNTAINS AS SKIES CLEAR. AS COOL HIGH PRESSURE BUILDS IN FOR SUNDAY
NIGHT...SOME INTERIOR VALLEYS MAY SEE AREAS OF FROST. AND CERTAIN
HIGH ELEVATIONS COULD EXPERIENCE AN ADVECTIVE FROST. WITH HIGH
PRESSURE STILL BUILDING INTO THE REGION...THERE SHOULD STILL BE
ENOUGH OF FLOW THROUGH THE MAJOR VALLEYS TO KEEP FROST FROM FORMING.
OVERALL...CONFIDENCE IS GOOD THAT SHELTERED VALLEYS WILL SEE SOME
FROST...THOUGH I/M NOT CERTAIN HOW WIDESPREAD IT WILL BE AT THIS
POINT. WE WILL CONTINUE TO MENTION THIS POSSIBILITY IN THE HWO.
MONDAY WILL BE SUNNY AND PLEASANT WITH MAX TEMPS RUNNING ABOUT 10
DEGREES BELOW NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...THE GLOBAL MODELS CONTINUE TO AGREE THAT
THE SHARP UPPER TROUGH AXIS WILL MOVE OFFSHORE MON NIGHT FOLLOWED BY
UPPER RIDGING TUE/WED. THE UPPER RIDGE AXIS WILL CROSS THE FORECAST
AREA WED NIGHT AND THE UPPER PATTERN BECOMES SWLY BY THU WITH A LOW
AMPLITUDE UPPER TROUGH APPROACHING FROM THE WEST. THE TROUGH AXIS
WILL THEN CROSS THE REGION ON FRI.
AT THE SURFACE...COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN
MON NIGHT AND SETTLES OVER THE REGION TUE. TEMPS ON MON NIGHT SHOULD
RUN 10-15 DEGREES BELOW NORMAL WITH FROST/FREEZE POSSIBLE OVER THE
NC MOUNTAINS/VALLEYS. MAX TEMPS ON TUE WILL REBOUND 2 TO 3 DEGREES
BUT STILL LIKELY REMAIN 5-10 DEGREES BELOW NORMAL. TEMPS QUICKLY
WARM UP TO NEAR NORMAL BY WED AFTERNOON AS THE CENTER OF HIGH
PRESSURE MOVES OFFSHORE AND RETURN SWLY FLOW DEVELOPS OVER THE
REGION. THE HIGH WILL REMAIN CENTERED OFF THE ATLANTIC COAST THU
WITH ITS SURFACE RIDGE EXTENDING INTO THE CWA. CONDITIONS LOOK DRY
THROUGH WED AND I/VE MENTIONED 20/30 PERCENT POPS FOR THUNDERSTORMS
LATE THURSDAY...MAINLY IN THE MOUNTAINS DUE TO INCREASING
MOISTURE/BUOYANCY. A SURFACE COLD FRONT WILL APPROACH THE SOUTHERN
APPALACHIANS BY THU NIGHT AND TRAVERS THE FORECAST AREA ON FRI.
HOWEVER...MODELS INDICATE THAT THE FRONT WILL WEAKEN AS IT MOVES
ACROSS REGION. THEREFORE...I HAVE KEPT POPS IN THE 20 TO 30 PERCENT
RANGE ON FRI. TEMPS WILL REMAIN A FEW DEGREES ABOVE NORMAL THU/FRI.
&&
.AVIATION /20Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A THIN BKN-OVC CIRRUS LAYER HAS STREAMED INTO THE AREA
FROM THE WEST...BUT IS NOT ENUF TO INHIBIT CONVECTIVE CUMULUS TO
DEVELOP TO THE WEST OF THE TERMINAL. SCATTERED SHRA AND A FEW TSRA
ARE EXPECTED TO DEVELOP ACRS THE AREA DURING THE AFTN HOURS. FOR
NOW...WILL GO WITH A TEMPO SHRA DURING THE PEAK HEATING HOURS...AS
TS CHCS TOO LOW ATTM. MAY NEED TO ADD IN TS MENTION...POSSIBLY AS A
TEMPO GROUP WITH A LATER AMD...IF COVERAGE ENDS UP GREATER THAN
EXPECTED. OTHERWISE...SW WINDS ARE GENERALLY 10-15 KTS WITH GUSTS
NEAR 20 KTS. THEY SHUD DIMINISH AROUND SUNSET SLIGHTLY AND LOSE THE
GUSTINESS. THERE WILL BE PLENTY OF MID AND UPR LVL MOISTURE
LINGERING OVERNIGHT...WITH SOME SHRA/TSRA POSSIBLE...ESP IN THE
09Z-12Z TIME FRAME. NOT CONFIDENT ENUF ON TS TO HAVE PROB30
THERE...BUT STILL EXPECT ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY
MORNING...WHICH WARRANTS A PROB30 AFTER 13Z. GUIDANCE NOT INDICATING
ANY RESTRICTIONS...BUT SOME FOG/STRATUS IS POSSIBLE LATE TNGT IF
THERE IS MORE RAINFALL THAN EXPECTED THIS AFTN/EVE.
ELSEWHERE...SCATTERED SHRA HAVE ALREADY DEVELOPED BEFORE THE 18Z TAF
ISSUANCE TO THE WEST OF A KAVL/KGMU/KAND LINE. THIS ACTIVITY IS
EXPECTED TO INCREASE IN COVERAGE AND SPREAD ACRS THE TAF SITES THIS
AFTN THRU ABOUT SUNSET. THE SCATTERED NATURE OF THE ACTIVITY SEEMS
TO WARRANT JUST VCTS MENTIONS FOR NOW. THERE WILL BE PLENTY OF MID
AND UPR LVL MOISTURE LINGERING OVERNIGHT...WITH SOME SHRA/TSRA
POSSIBLE. OVERALL...NOT EXPECTING MUCH FOG/STRATUS
POTENTIAL...EXCEPT IF A SITE IS HIT DIRECTLY BY A SHRA. STILL EXPECT
ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY MORNING...WHICH WARRANTS A
PROB30 AFTER DAYBREAK AT ALL SITES.
OUTLOOK...THE FIRST OF TWO COLD FRONT WILL SWEEP ACROSS THE REGION
ON SATURDAY. THE SECOND COLD FRONT WILL PASS EARLY SUNDAY. SHOWERS
AND THUNDERSTORMS WILL DEVELOP AHEAD OF THESE FRONTS...ESPECIALLY
SATURDAY. DRY WEATHER WILL BEGIN ON MONDAY.
CONFIDENCE TABLE...
19-01Z 01-07Z 07-13Z 13-19Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 91% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...JOH
AVIATION...ARK/JAT
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
231 PM EDT FRI MAY 10 2013
.SYNOPSIS...
SOUTHWEST FLOW AND MOISTURE WILL INCREASE TODAY THROUGH TONIGHT
AHEAD OF AN APPROACHING COLD FRONT. MOISTURE AND INSTABILITY WILL
LINGER THROUGH SATURDAY AS A SECOND REINFORCING FRONT APPROACHES
FROM THE NORTHWEST. THIS FRONT WILL CROSS THE REGION SUNDAY MORNING
AND USHER IN A DRIER AIRMASS ALONG WITH MUCH COOLER TEMPERATURES.
COOL HIGH PRESSURE WILL LINGER MONDAY THROUGH TUESDAY...WITH
TEMPERATURES REBOUNDING MID WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 200 PM...A PRE-FRONTAL SHORTWAVE TROF...ASSOCIATED WITH A PAIR
OF MCV/S WILL CROSS THE CWFA THIS EVENING. THE ENVIRONMENT IS FAIRLY
UNSTABLE...WITH SBCAPES IN THE 1000-1500 J/KG...HIGHEST ACRS THE
UPSTATE AND NE GA. DIFFERENTIAL HEATING IN THE MTNS AND ALONG EDGE
OF THE THICKER CIRRUS SHIELD IS HELPING TO INITIATE SCATTERED SHWR
COVERAGE ALREADY EARLY THIS AFTN. THE 16Z HRRR SEEMS TO HAVE THE
CLOSEST IDEA OF THE ACTIVITY COVERAGE...AND IT TAKES IT EWD ACRS THE
CWFA THRU THE REST OF THE AFTN...BRINGING IN THE MORE STABLE MCV AIR
IN FROM THE WEST. THE ENVIRONMENT STILL DOES NOT LOOK ALL THAT
IMPRESSIVE FROM A SEVERE THREAT STANDPOINT. SO WILL CONTINUE TO ONLY
MENTION LGTNG/HVY RAIN IN HWO. AS FOR HYDRO/HVY RAIN THREAT...WITH
THE MOVEMENT OF THE SHORTWAVE AND OVERALL CONVECTION...THINK ANY
AREAS RECEIVING AN INCH OR MORE WITH ONE STORM IS STILL FAIRLY LOW.
MOST AREAS PROBABLY WILL RECEIVE LESS THAN A QUARTER INCH THRU
TONIGHT.
AS COLD FRONT APPROACHES FROM THE WEST...PROFILES ACRS THE CWFA
REMAIN MOIST...WITH PERSISTENT DEEP LAYER WEAK-MOD Q-VECTOR
CONVERGENCE. CONVECTION ALLOWING MODELS DO SHOW MAINLY DEBRIS SHWRS
WITH POTENTIALLY A FEW RUMBLES OF THUNDER OVERNIGHT. THE MAIN
LIMITING FACTOR TO MORE ROBUST CONVECTION/HEAVY RAIN WILL BE ONGOING
CONVECTION ALONG THE GULF COAST...WHICH WILL ROB THE SRN
APPALACHIANS OF THE HIGHER PWAT AIR. WILL CONTINUE WITH 30-40 POP IN
THE PIEDMONT AND 50-60 IN THE MTNS. TEMPS WILL BE ABOVE NORMAL IN
THE MOIST PRE-FRONTAL AIR MASS.
SATURDAY...COLD FRONT AND ASSOCIATED MID LVL SHORTWAVE TROF WILL
CROSS THE AREA DURING THE DAY. LLVL FLOW VEERS TO NEARLY DUE
WESTERLY AHEAD OF THE SFC BNDRY...WITH PWATS DROPPING. WILL CONTINUE
WITH LIKELY POPS IN THE NC ZONES...AND HIGH-END CHC SOUTH. SEVERE
THREAT LOOKS TO STAY EAST WHERE BETTER SHEAR AND INSTBY WILL SET UP.
QPF STILL LOOKS TO BE LIMITED...AS STORMS SHUD HAVE DECENT EWD
MOTION...AND DRY AIR BEGINS TO FILTER IN. TEMPS ARE EXPECTED TO
REACH THE 70S BELOW 3500 FT...TO LWR 80S IN THE LWR PIEDMONT.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
AS OF 145 PM EDT FRIDAY...A STRONG UPPER LOW WILL MOVE ACROSS THE
GREAT LAKES STATES SATURDAY NIGHT AND SUNDAY. THIS WILL PUSH A COLD
FRONT ACROSS THE REGION EARLY ON SUNDAY. SATURDAY NIGHT THE UPPER
LEVEL FLOW WILL BACK JUST A BIT AHEAD OF THE ADVANCING UPPER
LOW...THOUGH THE LLVL FLOW WILL REMAIN OUT OF THE WEST TO NORTHWEST.
INSTABILITY WILL BE QUITE LIMITED AFTER MID-EVENING...AND WHILE
THERE WILL BE SOME FORCING FOR SHOWERS AND TSTMS OVER THE EASTERN
ZONES...THE THREAT OF SEVERE WEATHER WILL BE MINIMAL.
BY SUNDAY MORNING A BAND OF LOW TOPPED SHOWERS MAY MOVE INTO THE
MOUNTAINS ALONG THE TRUE COLD FRONT. ANY MEASURE RAINFALL WITH THESE
SHOWERS SHOULD BE CONFINED TO THE IMMEDIATE TENNESSEE BORDER.
SUNDAY WILL BE PLEASANTLY MILD. IT WILL BE BREEZY ACROSS THE
MOUNTAINS AS SKIES CLEAR. AS COOL HIGH PRESSURE BUILDS IN FOR SUNDAY
NIGHT...SOME INTERIOR VALLEYS MAY SEE AREAS OF FROST. AND CERTAIN
HIGH ELEVATIONS COULD EXPERIENCE AN ADVECTIVE FROST. WITH HIGH
PRESSURE STILL BUILDING INTO THE REGION...THERE SHOULD STILL BE
ENOUGH OF FLOW THROUGH THE MAJOR VALLEYS TO KEEP FROST FROM FORMING.
OVERALL...CONFIDENCE IS GOOD THAT SHELTERED VALLEYS WILL SEE SOME
FROST...THOUGH I/M NOT CERTAIN HOW WIDESPREAD IT WILL BE AT THIS
POINT. WE WILL CONTINUE TO MENTION THIS POSSIBILITY IN THE HWO.
MONDAY WILL BE SUNNY AND PLEASANT WITH MAX TEMPS RUNNING ABOUT 10
DEGREES BELOW NORMAL.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
AS OF 200 PM EDT FRIDAY...THE GLOBAL MODELS CONTINUE TO AGREE THAT
THE SHARP UPPER TROUGH AXIS WILL MOVE OFFSHORE MON NIGHT FOLLOWED BY
UPPER RIDGING TUE/WED. THE UPPER RIDGE AXIS WILL CROSS THE FORECAST
AREA WED NIGHT AND THE UPPER PATTERN BECOMES SWLY BY THU WITH A LOW
AMPLITUDE UPPER TROUGH APPROACHING FROM THE WEST. THE TROUGH AXIS
WILL THEN CROSS THE REGION ON FRI.
AT THE SURFACE...COOL AND DRY CANADIAN HIGH PRESSURE WILL BUILD IN
MON NIGHT AND SETTLES OVER THE REGION TUE. TEMPS ON MON NIGHT SHOULD
RUN 10-15 DEGREES BELOW NORMAL WITH FROST/FREEZE POSSIBLE OVER THE
NC MOUNTAINS/VALLEYS. MAX TEMPS ON TUE WILL REBOUND 2 TO 3 DEGREES
BUT STILL LIKELY REMAIN 5-10 DEGREES BELOW NORMAL. TEMPS QUICKLY
WARM UP TO NEAR NORMAL BY WED AFTERNOON AS THE CENTER OF HIGH
PRESSURE MOVES OFFSHORE AND RETURN SWLY FLOW DEVELOPS OVER THE
REGION. THE HIGH WILL REMAIN CENTERED OFF THE ATLANTIC COAST THU
WITH ITS SURFACE RIDGE EXTENDING INTO THE CWA. CONDITIONS LOOK DRY
THROUGH WED AND I/VE MENTIONED 20/30 PERCENT POPS FOR THUNDERSTORMS
LATE THURSDAY...MAINLY IN THE MOUNTAINS DUE TO INCREASING
MOISTURE/BUOYANCY. A SURFACE COLD FRONT WILL APPROACH THE SOUTHERN
APPALACHIANS BY THU NIGHT AND TRAVERS THE FORECAST AREA ON FRI.
HOWEVER...MODELS INDICATE THAT THE FRONT WILL WEAKEN AS IT MOVES
ACROSS REGION. THEREFORE...I HAVE KEPT POPS IN THE 20 TO 30 PERCENT
RANGE ON FRI. TEMPS WILL REMAIN A FEW DEGREES ABOVE NORMAL THU/FRI.
&&
.AVIATION /19Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...A THIN BKN-OVC CIRRUS LAYER HAS STREAMED INTO THE AREA
FROM THE WEST...BUT IS NOT ENUF TO INHIBIT CONVECTIVE CUMULUS TO
DEVELOP TO THE WEST OF THE TERMINAL. SCATTERED SHRA AND A FEW TSRA
ARE EXPECTED TO DEVELOP ACRS THE AREA DURING THE AFTN HOURS. FOR
NOW...WILL GO WITH A TEMPO SHRA DURING THE PEAK HEATING HOURS...AS
TS CHCS TOO LOW ATTM. MAY NEED TO ADD IN TS MENTION...POSSIBLY AS A
TEMPO GROUP WITH A LATER AMD...IF COVERAGE ENDS UP GREATER THAN
EXPECTED. OTHERWISE...SW WINDS ARE GENERALLY 10-15 KTS WITH GUSTS
NEAR 20 KTS. THEY SHUD DIMINISH AROUND SUNSET SLIGHTLY AND LOSE THE
GUSTINESS. THERE WILL BE PLENTY OF MID AND UPR LVL MOISTURE
LINGERING OVERNIGHT...WITH SOME SHRA/TSRA POSSIBLE...ESP IN THE
09Z-12Z TIME FRAME. NOT CONFIDENT ENUF ON TS TO HAVE PROB30
THERE...BUT STILL EXPECT ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY
MORNING...WHICH WARRANTS A PROB30 AFTER 13Z. GUIDANCE NOT INDICATING
ANY RESTRICTIONS...BUT SOME FOG/STRATUS IS POSSIBLE LATE TNGT IF
THERE IS MORE RAINFALL THAN EXPECTED THIS AFTN/EVE.
ELSEWHERE...SCATTERED SHRA HAVE ALREADY DEVELOPED BEFORE THE 18Z TAF
ISSUANCE TO THE WEST OF A KAVL/KGMU/KAND LINE. THIS ACTIVITY IS
EXPECTED TO INCREASE IN COVERAGE AND SPREAD ACRS THE TAF SITES THIS
AFTN THRU ABOUT SUNSET. THE SCATTERED NATURE OF THE ACTIVITY SEEMS
TO WARRANT JUST VCTS MENTIONS FOR NOW. THERE WILL BE PLENTY OF MID
AND UPR LVL MOISTURE LINGERING OVERNIGHT...WITH SOME SHRA/TSRA
POSSIBLE. OVERALL...NOT EXPECTING MUCH FOG/STRATUS
POTENTIAL...EXCEPT IF A SITE IS HIT DIRECTLY BY A SHRA. STILL EXPECT
ANOTHER ROUND OF SHRA/TSRA LATER SATURDAY MORNING...WHICH WARRANTS A
PROB30 AFTER DAYBREAK AT ALL SITES.
OUTLOOK...THE FIRST OF TWO COLD FRONT WILL SWEEP ACROSS THE REGION
ON SATURDAY. THE SECOND COLD FRONT WILL PASS EARLY SUNDAY. SHOWERS
AND THUNDERSTORMS WILL DEVELOP AHEAD OF THESE FRONTS...ESPECIALLY
SATURDAY. DRY WEATHER WILL BEGIN ON MONDAY.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 94% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...LEV
NEAR TERM...ARK
SHORT TERM...MCAVOY
LONG TERM...JOH
AVIATION...ARK
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1249 PM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
TODAY APPEARS A LITTLE QUIETER THEN THE PAST FEW DAYS...AS OUR
STUBBORN UPPER LEVEL LOW IS FINALLY OOZING EAST OF OUR AREA. STILL
HAVE AREAS OF CLOUD COVER TO CONTEND WITH EARLY TODAY. HOWEVER
MOISTURE PROFILES ARE SUCH THAT THERE SHOULD BE A GENERAL CLEARING
THROUGH THE DAY OTHER THEN SOME STRATO CUMULUS POTENTIAL OVER PARTS
OF THE FORECAST AREA WHICH RECEIVED A GOOD WETTING RAINFALL THE PAST
FEW DAYS. BUT AS THE AFTERNOON PROGRESSES...ANY STRATO CUMULUS
POTENTIAL SHOULD DRY UP. WINDS LOOK TO BE FAIRLY LIGHT AHEAD OF
TONIGHTS COLD FRONT. THIS WILL KEEP MIXING POTENTIAL DOWN A BIT...
SO KEPT HIGHS A FEW DEGREES EITHER SIDE OF SEASONAL NORMALS. ONE
THING TO WATCH FOR ARE DEW POINT TEMPERATURES IN OUR FAR WESTERN
ZONES. GUIDANCE DEW POINT VALUES HAVE BEEN CONSISTENTLY TOO HIGH IN
OUR CENTRAL SD ZONES FOR DAYS NOW. DEW POINT READINGS SHOULD RAISE
EARLY TODAY. HOWEVER ONCE THE SURFACE WINDS GO WESTERLY THIS
AFTERNOON AHEAD OF THE COLD FRONT...NOT SURE WHY LOCATIONS AROUND
CHAMBERLAIN WOULD HAVE DEW POINTS IN THE LOWER 40S AS SUGGESTED BY
SOME GUIDANCES. RAP AND HRRR LOOK TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION IN THAT AREA...AND DO INDEED DRY OUT OUR FAR
WESTERN ZONES THIS AFTERNOON. THEREFORE BLENDED THOSE TWO MODELS
INTO SOME OF THE MORE REASONABLE LOOKING CONSENSUS READINGS TO GIVE
DRIER MINIMUM HUMIDITY VALUES IN CENTRAL SD. CONCERNING
PRECIPITATION...AT THE MOMENT IT LOOKS DRY. HOWEVER RIGHT ALONG A
SUBTLE SURFACE CONVERGENCE AXIS WEST OF I 29...MAY NEED TO WATCH FOR
A FEW SPRINKLES OR AN ISOLATED LIGHT SHOWER EARLY TODAY IN THOSE
LOCATIONS.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
COLD FRONT PROGGED TO CROSS THE CWA TONIGHT...ENTERING THE
NORTHWEST PORTION OF OUR CWA BY 03Z AND EXITING NORTHWEST IOWA BY
09Z. BEST LARGE SCALE FORCING AND DEEPER MOISTURE STAYS OFF TO OUR
NORTHEAST. THUS THE GREATEST PRECIP POTENTIAL SHOULD BE NORTHEAST OF
US OVER MINNESOTA...WITH OUR AREA HAVING TO RELY ON ANY CONVECTION
THAT CAN GET GOING. HOWEVER IT IS A DECENT FRONTAL BOUNDARY...WITH
POTENTIALLY JUST ENOUGH LOW TO MID LEVEL THETAE ADVECTION TO INDEED
KICK OFF A FEW SHOWERS...THUS WILL KEEP THE LOW POPS GOING. JUST
ENOUGH INSTABILITY TO MAYBE GET A FEW RUMBLES OF THUNDER AS WELL.
DECENT LOW LEVEL JET OF WINDS BEHIND THE FRONT WITH A QUICK SHOT OF
CAA AS WELL. THUS NOT SURPRISING THAT MODEL SOUNDINGS SHOW THE
OPPORTUNITY FOR A PERIOD OF GUSTY WINDS RIGHT BEHIND THE FRONT
TONIGHT. MAY BE ABLE TO GET SOME 40 MPH GUSTS DOWN TO THE SURFACE
FOR A FEW HOURS FOLLOWING THE FRONTAL BOUNDARY AS WE MIX INTO THE 30
TO 40 KT JET. SO SOMETHING TO KEEP AN EYE ON.
EXPECT WINDS TO DROP OFF SOME SATURDAY MORNING AS MIXING WEAKENS A
BIT AND THE JET PUSHES SOUTHEAST OF THE AREA. HOWEVER AS DEEPER
MIXING BEGINS WITH DAYTIME HEATING WINDS WILL ONCE AGAIN INCREASE.
NORTHERLY WINDS GUSTING 25 TO 35 MPH LOOK LIKELY FROM MID MORNING
INTO THE AFTERNOON HOURS. IT WILL BE A CHILLY ONE TOO...WITH HIGHS
RANGING FROM THE LOW 50S OVER SOUTHWEST MINNESOTA TO AROUND 60 ALONG
THE MISSOURI RIVER. SHOULD AT LEAST BE MOSTLY SUNNY THOUGH...WITH
JUST A FEW AFTERNOON FAIR WEATHER CU. SURFACE HIGH PRESSURE QUICKLY
BUILDS IN SATURDAY NIGHT...WITH IDEAL RADIATIONAL COOLING EXPECTED
OVER MOST OF THE CWA. GIVEN THE COOL LOW LEVEL TEMPERATURE PROFILES
IN PLACE...EXPECTING A COLD NIGHT. WENT AT OR BELOW THE COLDEST
GUIDANCE...WITH UPPER 20S TO LOW 30S OVER MOST OF THE AREA. HOWEVER
IF CURRENT TRENDS PERSIST...WOULD NOT BE SURPRISED TO SEE SOME MID
20S IN SOME OF THE COOLER LOCATIONS EAST OF THE JAMES RIVER.
NEEDLESS TO SAY...LOOKS LIKE FROST OR FREEZE HEADLINES WILL BE
NEEDED FOR MOST OF THE CWA.
THE TROUGH EXITS TO OUR EAST ON SUNDAY...ALLOWING FOR A SLOW WARMUP
TO BEGIN. HIGHS WILL STILL BE BELOW NORMAL THOUGH...WITH UPPER 50S
AND LOW 60S EAST AND UPPER 60S WEST. WINDS WILL BE PRETTY LIGHT AND
THE SUN SHOULD BE SHINING BRIGHT...THUS NOT A BAD DAY OVERALL. OUR
REAL WARMTH BEGINS TO MOVE IN MONDAY AS UPPER RIDGING BUILDS IN.
HIGHS MONDAY A BIT TRICKY...WITH A SHARP GRADIENT LIKELY. AROUND 90
SEEMS ALMOST CERTAIN IN SOUTH CENTRAL SOUTH DAKOTA THOUGH...WITH THE
GREATER UNCERTAINTY TO THE EAST. MODELS BOUNCING AROUND A BIT ON HOW
QUICKLY WARM AIR MOVES IN EAST OF THE JAMES...BUT MID 70S TO MID 80S
LOOK PROBABLE. TUESDAY SHOULD BE THE HOTTEST DAY OF THE YEAR THUS
FAR. MODELS HAVE SLOWED DOWN THE WEAK FRONT...MEANING WE SHOULD GET
THE FULL FORCE OF THE HEAT. 850MB TEMPERATURES ARE QUITE
IMPRESSIVE...RUNNING CLOSE TO THE CLIMATOLOGICAL MAX FOR THIS TIME
OF YEAR. WENT WELL ABOVE ALLBLEND FOR HIGHS...WITH UPPER 80S TO LOW
90S LOOKING LIKE A GOOD BET FOR THE ENTIRE CWA. HOWEVER...IT SEEMS
QUITE POSSIBLE THAT AN AREA OF MID TO UPPER 90S WILL OCCUR IN A
CORRIDOR JUST AHEAD OF THE FRONT. TRYING TO PIN DOWN WHERE THIS WILL
OCCUR IS TOUGH THIS FAR OUT...AS IT COULD REALISTICALLY BE AS FAR
WEST AS CENTRAL SOUTH DAKOTA...OR AS SOUTHEAST AS NORTHWEST IOWA.
THUS DID NOT WANT TO GO TOO HIGH WITH FORECAST MAXES THIS FAR
OUT...GIVEN THE CURRENT FORECAST IS ALREADY 20 DEGREES ABOVE NORMAL.
MODELS DIVERGE A BIT AFTER TUESDAY...BUT GENERAL CONSENSUS IS FOR
THE RIDGE TO FLATTEN AS WAVES TO OUR NORTH PUSH A FRONTAL BOUNDARY
SOUTH THROUGH THE NORTHERN PLAINS. STRENGTH OF THIS BOUNDARY STILL
UNCERTAIN...BUT EITHER WAY IT SHOULD BE COOLER WEDNESDAY AND
THURSDAY...WITH HIGHS EITHER IN THE 70S OR 80S DEPENDING ON FRONTAL
STRENGTH. PRECIP CHANCES TOUGH TO PIN DOWN...OTHER THAN THAT IT
LOOKS LIKE THERE GOOD BE SOME ISOLATED TO SCATTERED CONVECTION
ANYTIME TUESDAY NIGHT ON AS THE WEAK WAVES AND FRONTS PUSH
ACROSS...BUT NOT EXPECTING ANYTHING WIDESPREAD OR SIGNIFICANT AT
THIS POINT.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1249 PM CDT FRI MAY 10 2013
GENERALLY VFR CONDITIONS EXPECTED THROUGH 11/18Z. HOWEVER STRONG
WINDS WILL ARRIVE BEHIND COLD FRONT WITH NORTHWEST WINDS GUSTING
BRIEFLY TO AS HIGH AS 40 KNOTS...THEN 25 TO 30 KNOT GUSTS AFTER
08Z THROUGH 18Z. SCATTERED TSRA POSSIBLE WITH FRONT AS IT CROSSES
AREA FROM THE NORTHWEST 02Z-08Z VERY BRIEF AND LOCAL VISIBILITY
REDUCTIONS TO 3-5SM POSSIBLE IN THUNDERSTORMS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJF
LONG TERM...CHENARD
AVIATION...
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
654 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
TODAY APPEARS A LITTLE QUIETER THEN THE PAST FEW DAYS...AS OUR
STUBBORN UPPER LEVEL LOW IS FINALLY OOZING EAST OF OUR AREA. STILL
HAVE AREAS OF CLOUD COVER TO CONTEND WITH EARLY TODAY. HOWEVER
MOISTURE PROFILES ARE SUCH THAT THERE SHOULD BE A GENERAL CLEARING
THROUGH THE DAY OTHER THEN SOME STRATO CUMULUS POTENTIAL OVER PARTS
OF THE FORECAST AREA WHICH RECEIVED A GOOD WETTING RAINFALL THE PAST
FEW DAYS. BUT AS THE AFTERNOON PROGRESSES...ANY STRATO CUMULUS
POTENTIAL SHOULD DRY UP. WINDS LOOK TO BE FAIRLY LIGHT AHEAD OF
TONIGHTS COLD FRONT. THIS WILL KEEP MIXING POTENTIAL DOWN A BIT...
SO KEPT HIGHS A FEW DEGREES EITHER SIDE OF SEASONAL NORMALS. ONE
THING TO WATCH FOR ARE DEW POINT TEMPERATURES IN OUR FAR WESTERN
ZONES. GUIDANCE DEW POINT VALUES HAVE BEEN CONSISTENTLY TOO HIGH IN
OUR CENTRAL SD ZONES FOR DAYS NOW. DEW POINT READINGS SHOULD RAISE
EARLY TODAY. HOWEVER ONCE THE SURFACE WINDS GO WESTERLY THIS
AFTERNOON AHEAD OF THE COLD FRONT...NOT SURE WHY LOCATIONS AROUND
CHAMBERLAIN WOULD HAVE DEW POINTS IN THE LOWER 40S AS SUGGESTED BY
SOME GUIDANCES. RAP AND HRRR LOOK TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION IN THAT AREA...AND DO INDEED DRY OUT OUR FAR
WESTERN ZONES THIS AFTERNOON. THEREFORE BLENDED THOSE TWO MODELS
INTO SOME OF THE MORE REASONABLE LOOKING CONSENSUS READINGS TO GIVE
DRIER MINIMUM HUMIDITY VALUES IN CENTRAL SD. CONCERNING
PRECIPITATION...AT THE MOMENT IT LOOKS DRY. HOWEVER RIGHT ALONG A
SUBTLE SURFACE CONVERGENCE AXIS WEST OF I 29...MAY NEED TO WATCH FOR
A FEW SPRINKLES OR AN ISOLATED LIGHT SHOWER EARLY TODAY IN THOSE
LOCATIONS.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
COLD FRONT PROGGED TO CROSS THE CWA TONIGHT...ENTERING THE
NORTHWEST PORTION OF OUR CWA BY 03Z AND EXITING NORTHWEST IOWA BY
09Z. BEST LARGE SCALE FORCING AND DEEPER MOISTURE STAYS OFF TO OUR
NORTHEAST. THUS THE GREATEST PRECIP POTENTIAL SHOULD BE NORTHEAST OF
US OVER MINNESOTA...WITH OUR AREA HAVING TO RELY ON ANY CONVECTION
THAT CAN GET GOING. HOWEVER IT IS A DECENT FRONTAL BOUNDARY...WITH
POTENTIALLY JUST ENOUGH LOW TO MID LEVEL THETAE ADVECTION TO INDEED
KICK OFF A FEW SHOWERS...THUS WILL KEEP THE LOW POPS GOING. JUST
ENOUGH INSTABILITY TO MAYBE GET A FEW RUMBLES OF THUNDER AS WELL.
DECENT LOW LEVEL JET OF WINDS BEHIND THE FRONT WITH A QUICK SHOT OF
CAA AS WELL. THUS NOT SURPRISING THAT MODEL SOUNDINGS SHOW THE
OPPORTUNITY FOR A PERIOD OF GUSTY WINDS RIGHT BEHIND THE FRONT
TONIGHT. MAY BE ABLE TO GET SOME 40 MPH GUSTS DOWN TO THE SURFACE
FOR A FEW HOURS FOLLOWING THE FRONTAL BOUNDARY AS WE MIX INTO THE 30
TO 40 KT JET. SO SOMETHING TO KEEP AN EYE ON.
EXPECT WINDS TO DROP OFF SOME SATURDAY MORNING AS MIXING WEAKENS A
BIT AND THE JET PUSHES SOUTHEAST OF THE AREA. HOWEVER AS DEEPER
MIXING BEGINS WITH DAYTIME HEATING WINDS WILL ONCE AGAIN INCREASE.
NORTHERLY WINDS GUSTING 25 TO 35 MPH LOOK LIKELY FROM MID MORNING
INTO THE AFTERNOON HOURS. IT WILL BE A CHILLY ONE TOO...WITH HIGHS
RANGING FROM THE LOW 50S OVER SOUTHWEST MINNESOTA TO AROUND 60 ALONG
THE MISSOURI RIVER. SHOULD AT LEAST BE MOSTLY SUNNY THOUGH...WITH
JUST A FEW AFTERNOON FAIR WEATHER CU. SURFACE HIGH PRESSURE QUICKLY
BUILDS IN SATURDAY NIGHT...WITH IDEAL RADIATIONAL COOLING EXPECTED
OVER MOST OF THE CWA. GIVEN THE COOL LOW LEVEL TEMPERATURE PROFILES
IN PLACE...EXPECTING A COLD NIGHT. WENT AT OR BELOW THE COLDEST
GUIDANCE...WITH UPPER 20S TO LOW 30S OVER MOST OF THE AREA. HOWEVER
IF CURRENT TRENDS PERSIST...WOULD NOT BE SURPRISED TO SEE SOME MID
20S IN SOME OF THE COOLER LOCATIONS EAST OF THE JAMES RIVER.
NEEDLESS TO SAY...LOOKS LIKE FROST OR FREEZE HEADLINES WILL BE
NEEDED FOR MOST OF THE CWA.
THE TROUGH EXITS TO OUR EAST ON SUNDAY...ALLOWING FOR A SLOW WARMUP
TO BEGIN. HIGHS WILL STILL BE BELOW NORMAL THOUGH...WITH UPPER 50S
AND LOW 60S EAST AND UPPER 60S WEST. WINDS WILL BE PRETTY LIGHT AND
THE SUN SHOULD BE SHINING BRIGHT...THUS NOT A BAD DAY OVERALL. OUR
REAL WARMTH BEGINS TO MOVE IN MONDAY AS UPPER RIDGING BUILDS IN.
HIGHS MONDAY A BIT TRICKY...WITH A SHARP GRADIENT LIKELY. AROUND 90
SEEMS ALMOST CERTAIN IN SOUTH CENTRAL SOUTH DAKOTA THOUGH...WITH THE
GREATER UNCERTAINTY TO THE EAST. MODELS BOUNCING AROUND A BIT ON HOW
QUICKLY WARM AIR MOVES IN EAST OF THE JAMES...BUT MID 70S TO MID 80S
LOOK PROBABLE. TUESDAY SHOULD BE THE HOTTEST DAY OF THE YEAR THUS
FAR. MODELS HAVE SLOWED DOWN THE WEAK FRONT...MEANING WE SHOULD GET
THE FULL FORCE OF THE HEAT. 850MB TEMPERATURES ARE QUITE
IMPRESSIVE...RUNNING CLOSE TO THE CLIMATOLOGICAL MAX FOR THIS TIME
OF YEAR. WENT WELL ABOVE ALLBLEND FOR HIGHS...WITH UPPER 80S TO LOW
90S LOOKING LIKE A GOOD BET FOR THE ENTIRE CWA. HOWEVER...IT SEEMS
QUITE POSSIBLE THAT AN AREA OF MID TO UPPER 90S WILL OCCUR IN A
CORRIDOR JUST AHEAD OF THE FRONT. TRYING TO PIN DOWN WHERE THIS WILL
OCCUR IS TOUGH THIS FAR OUT...AS IT COULD REALISTICALLY BE AS FAR
WEST AS CENTRAL SOUTH DAKOTA...OR AS SOUTHEAST AS NORTHWEST IOWA.
THUS DID NOT WANT TO GO TOO HIGH WITH FORECAST MAXES THIS FAR
OUT...GIVEN THE CURRENT FORECAST IS ALREADY 20 DEGREES ABOVE NORMAL.
MODELS DIVERGE A BIT AFTER TUESDAY...BUT GENERAL CONSENSUS IS FOR
THE RIDGE TO FLATTEN AS WAVES TO OUR NORTH PUSH A FRONTAL BOUNDARY
SOUTH THROUGH THE NORTHERN PLAINS. STRENGTH OF THIS BOUNDARY STILL
UNCERTAIN...BUT EITHER WAY IT SHOULD BE COOLER WEDNESDAY AND
THURSDAY...WITH HIGHS EITHER IN THE 70S OR 80S DEPENDING ON FRONTAL
STRENGTH. PRECIP CHANCES TOUGH TO PIN DOWN...OTHER THAN THAT IT
LOOKS LIKE THERE GOOD BE SOME ISOLATED TO SCATTERED CONVECTION
ANYTIME TUESDAY NIGHT ON AS THE WEAK WAVES AND FRONTS PUSH
ACROSS...BUT NOT EXPECTING ANYTHING WIDESPREAD OR SIGNIFICANT AT
THIS POINT.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 652 AM CDT FRI MAY 10 2013
SOME LOCALIZED UPPER END IFR TO LOWER END MVFR CEILINGS WILL BE
PREVALENT IN THE MISSOURI RIVER VALLEY EARLY THIS MORNING.
OTHERWISE THE CURRENT CLOUD COVER WEST OF INTERSTATE 29 IS VFR. BY
LATE MORNING AND AFTERNOON...ALL LOCATIONS WILL BE VFR...WITH THAT
CONTINUING INTO TONIGHT. ONE OF THE MAIN AVIATION FEATURES
CONCERNS TONIGHT IN THAT A STRONG COLD FRONT WILL BE MOVING
THROUGH OUR FORECAST AREA. A FEW SHOWERS OR THUNDERSTORMS ARE
POSSIBLE ALONG THE FRONTAL PASSAGE. HOWEVER THE BIGGER CONCERN
WILL LIKELY BE WIND SPEEDS. AS WINDS SHIFT TO THE NORTH...WINDS
WILL LIKELY GUST BETWEEN 35 AND 40 KNOTS FOR A COUPLE OF HOURS
BEHIND THE FRONTAL PASSAGE.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJF
LONG TERM...CHENARD
AVIATION...MJF
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
411 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
TODAY APPEARS A LITTLE QUIETER THEN THE PAST FEW DAYS...AS OUR
STUBBORN UPPER LEVEL LOW IS FINALLY OOZING EAST OF OUR AREA. STILL
HAVE AREAS OF CLOUD COVER TO CONTEND WITH EARLY TODAY. HOWEVER
MOISTURE PROFILES ARE SUCH THAT THERE SHOULD BE A GENERAL CLEARING
THROUGH THE DAY OTHER THEN SOME STRATO CUMULUS POTENTIAL OVER PARTS
OF THE FORECAST AREA WHICH RECEIVED A GOOD WETTING RAINFALL THE PAST
FEW DAYS. BUT AS THE AFTERNOON PROGRESSES...ANY STRATO CUMULUS
POTENTIAL SHOULD DRY UP. WINDS LOOK TO BE FAIRLY LIGHT AHEAD OF
TONIGHTS COLD FRONT. THIS WILL KEEP MIXING POTENTIAL DOWN A BIT...
SO KEPT HIGHS A FEW DEGREES EITHER SIDE OF SEASONAL NORMALS. ONE
THING TO WATCH FOR ARE DEW POINT TEMPERATURES IN OUR FAR WESTERN
ZONES. GUIDANCE DEW POINT VALUES HAVE BEEN CONSISTENTLY TOO HIGH IN
OUR CENTRAL SD ZONES FOR DAYS NOW. DEW POINT READINGS SHOULD RAISE
EARLY TODAY. HOWEVER ONCE THE SURFACE WINDS GO WESTERLY THIS
AFTERNOON AHEAD OF THE COLD FRONT...NOT SURE WHY LOCATIONS AROUND
CHAMBERLAIN WOULD HAVE DEW POINTS IN THE LOWER 40S AS SUGGESTED BY
SOME GUIDANCES. RAP AND HRRR LOOK TO HAVE THE BEST HANDLE ON THE
CURRENT SITUATION IN THAT AREA...AND DO INDEED DRY OUT OUR FAR
WESTERN ZONES THIS AFTERNOON. THEREFORE BLENDED THOSE TWO MODELS
INTO SOME OF THE MORE REASONABLE LOOKING CONSENSUS READINGS TO GIVE
DRIER MINIMUM HUMIDITY VALUES IN CENTRAL SD. CONCERNING
PRECIPITATION...AT THE MOMENT IT LOOKS DRY. HOWEVER RIGHT ALONG A
SUBTLE SURFACE CONVERGENCE AXIS WEST OF I 29...MAY NEED TO WATCH FOR
A FEW SPRINKLES OR AN ISOLATED LIGHT SHOWER EARLY TODAY IN THOSE
LOCATIONS.
.LONG TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 408 AM CDT FRI MAY 10 2013
COLD FRONT PROGGED TO CROSS THE CWA TONIGHT...ENTERING THE
NORTHWEST PORTION OF OUR CWA BY 03Z AND EXITING NORTHWEST IOWA BY
09Z. BEST LARGE SCALE FORCING AND DEEPER MOISTURE STAYS OFF TO OUR
NORTHEAST. THUS THE GREATEST PRECIP POTENTIAL SHOULD BE NORTHEAST OF
US OVER MINNESOTA...WITH OUR AREA HAVING TO RELY ON ANY CONVECTION
THAT CAN GET GOING. HOWEVER IT IS A DECENT FRONTAL BOUNDARY...WITH
POTENTIALLY JUST ENOUGH LOW TO MID LEVEL THETAE ADVECTION TO INDEED
KICK OFF A FEW SHOWERS...THUS WILL KEEP THE LOW POPS GOING. JUST
ENOUGH INSTABILITY TO MAYBE GET A FEW RUMBLES OF THUNDER AS WELL.
DECENT LOW LEVEL JET OF WINDS BEHIND THE FRONT WITH A QUICK SHOT OF
CAA AS WELL. THUS NOT SURPRISING THAT MODEL SOUNDINGS SHOW THE
OPPORTUNITY FOR A PERIOD OF GUSTY WINDS RIGHT BEHIND THE FRONT
TONIGHT. MAY BE ABLE TO GET SOME 40 MPH GUSTS DOWN TO THE SURFACE
FOR A FEW HOURS FOLLOWING THE FRONTAL BOUNDARY AS WE MIX INTO THE 30
TO 40 KT JET. SO SOMETHING TO KEEP AN EYE ON.
EXPECT WINDS TO DROP OFF SOME SATURDAY MORNING AS MIXING WEAKENS A
BIT AND THE JET PUSHES SOUTHEAST OF THE AREA. HOWEVER AS DEEPER
MIXING BEGINS WITH DAYTIME HEATING WINDS WILL ONCE AGAIN INCREASE.
NORTHERLY WINDS GUSTING 25 TO 35 MPH LOOK LIKELY FROM MID MORNING
INTO THE AFTERNOON HOURS. IT WILL BE A CHILLY ONE TOO...WITH HIGHS
RANGING FROM THE LOW 50S OVER SOUTHWEST MINNESOTA TO AROUND 60 ALONG
THE MISSOURI RIVER. SHOULD AT LEAST BE MOSTLY SUNNY THOUGH...WITH
JUST A FEW AFTERNOON FAIR WEATHER CU. SURFACE HIGH PRESSURE QUICKLY
BUILDS IN SATURDAY NIGHT...WITH IDEAL RADIATIONAL COOLING EXPECTED
OVER MOST OF THE CWA. GIVEN THE COOL LOW LEVEL TEMPERATURE PROFILES
IN PLACE...EXPECTING A COLD NIGHT. WENT AT OR BELOW THE COLDEST
GUIDANCE...WITH UPPER 20S TO LOW 30S OVER MOST OF THE AREA. HOWEVER
IF CURRENT TRENDS PERSIST...WOULD NOT BE SURPRISED TO SEE SOME MID
20S IN SOME OF THE COOLER LOCATIONS EAST OF THE JAMES RIVER.
NEEDLESS TO SAY...LOOKS LIKE FROST OR FREEZE HEADLINES WILL BE
NEEDED FOR MOST OF THE CWA.
THE TROUGH EXITS TO OUR EAST ON SUNDAY...ALLOWING FOR A SLOW WARMUP
TO BEGIN. HIGHS WILL STILL BE BELOW NORMAL THOUGH...WITH UPPER 50S
AND LOW 60S EAST AND UPPER 60S WEST. WINDS WILL BE PRETTY LIGHT AND
THE SUN SHOULD BE SHINING BRIGHT...THUS NOT A BAD DAY OVERALL. OUR
REAL WARMTH BEGINS TO MOVE IN MONDAY AS UPPER RIDGING BUILDS IN.
HIGHS MONDAY A BIT TRICKY...WITH A SHARP GRADIENT LIKELY. AROUND 90
SEEMS ALMOST CERTAIN IN SOUTH CENTRAL SOUTH DAKOTA THOUGH...WITH THE
GREATER UNCERTAINTY TO THE EAST. MODELS BOUNCING AROUND A BIT ON HOW
QUICKLY WARM AIR MOVES IN EAST OF THE JAMES...BUT MID 70S TO MID 80S
LOOK PROBABLE. TUESDAY SHOULD BE THE HOTTEST DAY OF THE YEAR THUS
FAR. MODELS HAVE SLOWED DOWN THE WEAK FRONT...MEANING WE SHOULD GET
THE FULL FORCE OF THE HEAT. 850MB TEMPERATURES ARE QUITE
IMPRESSIVE...RUNNING CLOSE TO THE CLIMATOLOGICAL MAX FOR THIS TIME
OF YEAR. WENT WELL ABOVE ALLBLEND FOR HIGHS...WITH UPPER 80S TO LOW
90S LOOKING LIKE A GOOD BET FOR THE ENTIRE CWA. HOWEVER...IT SEEMS
QUITE POSSIBLE THAT AN AREA OF MID TO UPPER 90S WILL OCCUR IN A
CORRIDOR JUST AHEAD OF THE FRONT. TRYING TO PIN DOWN WHERE THIS WILL
OCCUR IS TOUGH THIS FAR OUT...AS IT COULD REALISTICALLY BE AS FAR
WEST AS CENTRAL SOUTH DAKOTA...OR AS SOUTHEAST AS NORTHWEST IOWA.
THUS DID NOT WANT TO GO TOO HIGH WITH FORECAST MAXES THIS FAR
OUT...GIVEN THE CURRENT FORECAST IS ALREADY 20 DEGREES ABOVE NORMAL.
MODELS DIVERGE A BIT AFTER TUESDAY...BUT GENERAL CONSENSUS IS FOR
THE RIDGE TO FLATTEN AS WAVES TO OUR NORTH PUSH A FRONTAL BOUNDARY
SOUTH THROUGH THE NORTHERN PLAINS. STRENGTH OF THIS BOUNDARY STILL
UNCERTAIN...BUT EITHER WAY IT SHOULD BE COOLER WEDNESDAY AND
THURSDAY...WITH HIGHS EITHER IN THE 70S OR 80S DEPENDING ON FRONTAL
STRENGTH. PRECIP CHANCES TOUGH TO PIN DOWN...OTHER THAN THAT IT
LOOKS LIKE THERE GOOD BE SOME ISOLATED TO SCATTERED CONVECTION
ANYTIME TUESDAY NIGHT ON AS THE WEAK WAVES AND FRONTS PUSH
ACROSS...BUT NOT EXPECTING ANYTHING WIDESPREAD OR SIGNIFICANT AT
THIS POINT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1129 PM CDT THU MAY 9 2013
MVFR CEILINGS WILL CONTINUE TO PLAGUE AREAS FROM AROUND INTERSTATE
29 AND EASTWARD FOR MUCH OF TONIGHT AND EARLY MORNING AS LOW LEVEL
FLOW REMAINS WITH AN EASTERLY COMPONENT. DRIER AIR IN CENTRAL
MINNESOTA WILL EVENTUALLY HELP TO ERODE FROM THE NORTHEAST LATER
TONIGHT AND THROUGH MID MORNING ON FRIDAY...BUT WILL LIKELY LEAVE
A NORTH/SOUTH BAND OF STRATUS THAT WILL BE MORE DIFFICULT TO ERODE
BETWEEN THE JAMES VALLEY AND I 29...PERHAPS REMAINING UNTIL LATE
MORNING. OTHERWISE...WILL LIKELY CONTINUE TO SEE SOME ISOLATED SHOWER
DEVELOPMENT THROUGH 09Z-10Z THROUGH THE JAMES VALLEY AS WEAK LOW
LEVEL CONVERGENCE CONTINUES...WITH MARGINALLY WEAK INSTABILITY IN
THE MID LEVELS...BUT BELOW THRESHOLD FOR MENTION IN KHON TAF. A
STRONG COLD FRONT WILL MOVE THROUGH THE AREA ON FRIDAY EVENING.
SOME INSTABILITY FOR THUNDER THREAT...BUT MAINLY FOR AREAS
NORTHEAST OF A KHON TO KFSD TO KSPW LINE...AND WILL BE MAINLY AT
AND POST FRONTAL FOR A COUPLE HOURS.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
SHORT TERM...MJF
LONG TERM...CHENARD
AVIATION...CHAPMAN
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
322 PM CDT FRI MAY 10 2013
.SHORT TERM...
BAND OF STRONG TO SEVERE THUNDERSTORMS IN THE CONCHO VALLEY
SOUTHWEST INTO CROCKETT COUNTY...ASSOCIATED WITH A COLD
FRONT...WAS STEADILY MOVING SOUTHEAST THIS AFTERNOON. A SEVERE
THUNDERSTORMS WATCH IS IN EFFECT FOR MUCH OF WEST CENTRAL
TEXAS...SOUTH OF THE BIG COUNTRY UNTIL 10 PM CDT TONIGHT. ATMOSPHERE
WAS UNSTABLE THIS AFTERNOON AS COLDER AIR ALOFT...ASSOCIATED WITH
AN UPPER LEVEL TROUGH OVER NEW MEXICO MOVED EAST. SPC RAP SB CAPES
WERE 1500-2500 J/KG. THIS IS LOWER THAN YESTERDAY...BUT STILL
ENOUGH TO GET GOLFBALL SIZE HAIL IN COKE COUNTY FROM A SUPERCELL
HIS AFTERNOON.
SEVERE STORM ACTIVITY SHOULD NOT BE QUITE AS EXTENSIVE AS
YESTERDAY...AND SHOULD WEAKEN BY SUNSET WITH LOSS OF DAYTIME
HEATING AND PASSAGE OF THE COLD FRONT.
STILL KEEPING A CHANCE OF SHOWERS AND THUNDERSTORMS SATURDAY AS
THE UPPER TROUGH MOVES ACROSS THE REGION. DRIER AIR WILL ALSO MOVE
IN FROM NORTH TO SOUTH...SO SEVERE THUNDERSTORMS ARE NOT EXPECTED.
MOST STORMS SHOULD BE ALONG THE I-10 CORRIDOR AND END BY LATE
AFTERNOON.
04
.LONG TERM...
SHOWER AND THUNDERSTORM CHANCES RETURN TUESDAY AS A CUT OFF UPPER
LOW OVER BAJA CALIFORNIA MOVES NORTHEAST AND WEAKENS OVER NEW
MEXICO AND THE TEXAS PANHANDLE. MOVEMENT AND PLACEMENT OF CUT OFF
UPPER LOWS HAS ALWAYS BEEN DIFFICULT...ESPECIALLY WHEN THEY KICK
OUT. WILL KEEP POPS FAIRLY LOW AT THIS TIME...IN THE 20 TO 30
PERCENT RANGE...WITH THE HIGHER POPS ALONG THE I-10 CORRIDOR.
THUS IT POSSIBLE THAT THE SYSTEM BEGIN TO MOVE SLOWER THAN
FORECAST...DESPITE FAIRLY GOOD AGREEMENT IN RUN CONTINUITY AND
BETWEEN THE GFS AND EC MODELS. REMOVED POPS BY THURSDAY AS THE
UPPER DISTURBANCE MOVES NE AND AN UPPER RIDGE BUILDS IN.
04
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 56 80 54 79 58 / 20 10 10 5 5
SAN ANGELO 58 79 54 81 55 / 30 20 10 10 5
JUNCTION 58 77 53 81 53 / 30 20 10 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
04
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1017 PM CDT SAT MAY 11 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 228 PM CDT SAT MAY 11 2013
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE AND COLD FRONT ACROSS LOWER MICHIGAN THIS AFTERNOON.
BEHIND THE FRONT...A DEEP SHORTWAVE TROUGH COMBINED WITH STEEPENING
LOW LEVEL LAPSE RATES AND AMPLE LOW LEVEL MOISTURE ARE GENERATING
SCATTERED RAIN/SNOW/SLEET SHOWERS OVER EASTERN MINNESOTA TO CENTRAL
WISCONSIN...WHICH SHOULD ADVECT INTO EASTERN WISCONSIN LATER THIS
AFTERNOON. SOLID STRATUS DECK HAS HAD A DIFFICULT TIME ADVECTING
SOUTHWARD...BUT NOW EXTENDS FROM NORTHERN WISCONSIN TO HUDSON BAY.
STILL EXPECT THIS STRATUS DECK TO SAG SOUTH FOR THE REST OF THE
AFTERNOON...DRIVEN BY GUSTY NNW WINDS. FORECAST CONCERNS ARE
PRECIP TRENDS AND TEMPS...INCLUDING FROST/FREEZE HEADLINES.
TONIGHT...THE STRONG SHORTWAVE TROUGH WILL MOVE EAST OVER THE
CENTRAL GREAT LAKES THIS EVENING AND INTO FAR EASTERN ONTARIO
OVERNIGHT. BEHIND THE SHORTWAVE...A WIDESPREAD STRATUS DECK OVER
NORTHERN WISCONSIN AND ONTARIO SHOULD ADVECT SOUTH WITH THE HELP OF
MODERATELY STRONG NORTHERLY FLOW AND INCREASING INSTABILITY OF LAKE
SUPERIOR. WITH CYCLONIC FLOW AND COLD ADVECTION...TRENDED
CONSIDERABLY MORE CLOUDY WITH THE SKY COVER TONIGHT. STILL THINK
WILL SEE CLEARING SKIES AFTER MIDNIGHT OVER CENTRAL AND NORTHEAST
WISCONSIN AS MOISTURE IN THE COLUMN DRIES OUT. TEMPS THIS MORNING
OVER NORTHERN MINNESOTA WERE IN THE 32-34 DEGREE RANGE...WHICH WILL
BE THE AIRMASS ADVECTING INTO THE AREA TONIGHT. WITH NO CHANCE OF
DECOUPLING AND CLOUDS POTENTIALLY STICKING AROUND LONGER...HAVE
RAISED LOW TEMPS TOWARDS THE ECMWFBC GUIDANCE...WHICH IS USUALLY ONE
OF THE BETTER PERFORMING TEMP GUIDANCES. SINCE FROST IS A MINIMAL
CONCERN DUE TO WINDS REMAINING UP...HEADLINES ARE REALLY A FREEZE OR
NO FREEZE SCENARIO. WITH TEMPS ONLY BRIEFLY REACHING 32 DEGREES
LATE TONIGHT IN CENTRAL WISCONSIN...COORDINATION RESULTED IN A
DECISION TO GO WITH NO HEADLINES TONIGHT...BUT WILL STILL ADVISE
PEOPLE TO TAKE PRECAUTIONS WITH THEIR SENSITIVE PLANTS OVER CENTRAL
WISCONSIN IN THE HWO...IN CASE TEMPS DO FALL MORE THAN EXPECTED.
WILL GO WITH LOWS IN THE UPPER 20S NORTH...TO 32 DEGREES OVER
CENTRAL WISCONSIN...TO THE MID 30S NEAR LAKE MICHIGAN.
SUNDAY...LOW PRESSURE WILL MOVE FURTHER EAST INTO QUEBEC WHILE HIGH
PRESSURE BUILDS INTO THE REGION. THINK BROKEN CLOUD COVER WILL
CONTINUE TO RESIDE OVER NORTH-CENTRAL WISCONSIN TO START THE MORNING
WHICH SHOULD RETREAT TO THE NORTH. WITH DIURNAL HEATING
THOUGH...RATHER FLAT DIURNAL CU SHOULD DEVELOP BY LATE MORNING AND
THEN MIX OUT IN THE AFTERNOON. HIGHS TO TOP OUT IN THE MIDDLE 40S TO
LOWER 50S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 228 PM CDT SAT MAY 11 2013
MAIN FCST CONCERNS INCLUDE FREEZE HEADLINES FOR SUNDAY NIGHT...THE
POTENTIAL FOR SEVERE TSTMS LATE TUESDAY INTO TUESDAY NIGHT...AND
TEMPERATURES THROUGH THE PERIOD.
SFC HIGH PRESSURE WILL RESIDE OVER THE FORECAST AREA ON SUNDAY NIGHT.
CLEAR SKIES AND LIGHT/CALM WINDS WILL ALLOW TEMPS TO DROP BLO FREEZING
ACROSS ALL BUT THE LAKESHORE AREAS. WE HAVE NOT STARTED UP FROST/FREEZE
HEADLINES OVER NORTHERN WI YET...SO NO HEADLINES THERE DESPITE MIN TEMPS
IN THE LOW TO MID 20S. WILL KEEP THE FREEZE WATCH GOING ACROSS THE
SOUTHERN HALF OF THE CWA...AND WOULD ANTICIPATE THAT THIS WILL BE
UPGRADED A FREEZE WARNING WITH THE 4 AM SUNDAY FCST PACKAGE.
AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION MONDAY INTO TUESDAY...
WITH LOW-LEVEL WAA KICKING IN MONDAY INTO MONDAY NIGHT. THE WAA SURGE
WILL BRING INCREASING CLOUDS...WITH A CHANCE OF SHOWERS OVER OUR WSTRN
COUNTIES ON MONDAY...AND OVER THE ENTIRE CWA MONDAY NIGHT.
ON TUESDAY...A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO CENTRAL
WI DURING THE AFTERNOON. TEMPERATURES WILL BE A TOUGH CALL...AS CLOUDS
AND EAST WINDS NORTH OF THE FRONT COULD HOLD READINGS IN THE 50S/60S
OVER THE LAKESHORE AND FAR NE WI...WHILE MIXING THROUGH 850 MB OVER
CENTRAL WI WOULD BE SUPPORTIVE OF HIGHS IN THE UPPER 80S/LOWER 90S
IN THE FAR SW PART OF THE CWA. NOT CONFIDENT ENOUGH TO GO WITH THAT
LARGE OF A GRADIENT OVER THE FORECAST AREA...BUT WILL HAVE UPPER 50S/
LOWER 60S NEAR THE LAKE...WITH INLAND LOCATIONS RANGING FROM THE UPPER
60S OVER FAR NE WI TO THE LOWER 80S IN CENTRAL WI.
WILL CARRY A SLGT CHC/CHANCE OF TSTMS NORTH OF THE WARM FRONT ON
TUESDAY...AS THE MODELS SHOW A SURGE OF INSTABILITY ARRIVING DURING
THE AFTERNOON...BUT ALSO SOME POTENTIAL CAPPING. AM CONCERNED ABOUT
THE POTENTIAL FOR SVR TSTMS TUESDAY NIGHT...AS THE WARM FRONT LIFTS
NORTH...FOLLOWED BY THE COLD FRONTAL PASSAGE OVERNIGHT. MODELS ARE
IN DECENT AGREEMENT ON MUCAPE INCREASING TO 1500-2000 J/KG...
ALONG WITH DEEP LAYER SHEAR OF 45-55 KNOTS...0-3 KM HELICITIES OF
300-500...AND MID-LEVEL LAPSE RATES INCREASING TO 7-7.5 C/KM. THE
GFS MODEL SEEMS TO DEPICT THIS BEST...WITH A BULLSEYE OF QPF OVER
THE NE HALF OF THE FORECAST AREA. WILL ADD A MENTION OF POSSIBLE
SVR TSTMS LATE TUESDAY INTO TUESDAY NIGHT TO THE HAZARDOUS WEATHER
OUTLOOK.
THE COLD FRONT IS EXPECTED TO SHIFT SOUTH OF THE AREA WEDNESDAY INTO
THURSDAY NIGHT...RESULTING IN A GENERAL LULL IN THE PCPN. THE FRONT
WILL LIFT BACK TO THE NORTH LATE IN THE WEEK...BRINGING THE CHANCE
OF TSTMS BACK INTO THE REGION ON FRI/SAT.
ALTHOUGH TEMPERATURES WILL START OFF ON THE COOL SIDE...THEY SHOULD
AVERAGE ABOVE NORMAL FROM TUESDAY THROUGH SATURDAY.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1017 PM CDT SAT MAY 11 2013
MAINLY VFR CIGS WILL DRIFT OVER THE REGION TONIGHT
INTO SUNDAY. SCATTERED MVFR CIGS/VSBYS DUE OT SNOW SHOWERS WILL
LINGER OVER FAR NORTH CENTRAL WISCONSIN OVERNIGHT. GUSTY NORTHWEST WINDS
WILL ALSO PERSIST TONIGHT OVER NORTHEAST WISCONSIN.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
WIZ020-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
701 PM CDT SAT MAY 11 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND SUNDAY
ISSUED AT 228 PM CDT SAT MAY 11 2013
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE AND COLD FRONT ACROSS LOWER MICHIGAN THIS AFTERNOON.
BEHIND THE FRONT...A DEEP SHORTWAVE TROUGH COMBINED WITH STEEPENING
LOW LEVEL LAPSE RATES AND AMPLE LOW LEVEL MOISTURE ARE GENERATING
SCATTERED RAIN/SNOW/SLEET SHOWERS OVER EASTERN MINNESOTA TO CENTRAL
WISCONSIN...WHICH SHOULD ADVECT INTO EASTERN WISCONSIN LATER THIS
AFTERNOON. SOLID STRATUS DECK HAS HAD A DIFFICULT TIME ADVECTING
SOUTHWARD...BUT NOW EXTENDS FROM NORTHERN WISCONSIN TO HUDSON BAY.
STILL EXPECT THIS STRATUS DECK TO SAG SOUTH FOR THE REST OF THE
AFTERNOON...DRIVEN BY GUSTY NNW WINDS. FORECAST CONCERNS ARE
PRECIP TRENDS AND TEMPS...INCLUDING FROST/FREEZE HEADLINES.
TONIGHT...THE STRONG SHORTWAVE TROUGH WILL MOVE EAST OVER THE
CENTRAL GREAT LAKES THIS EVENING AND INTO FAR EASTERN ONTARIO
OVERNIGHT. BEHIND THE SHORTWAVE...A WIDESPREAD STRATUS DECK OVER
NORTHERN WISCONSIN AND ONTARIO SHOULD ADVECT SOUTH WITH THE HELP OF
MODERATELY STRONG NORTHERLY FLOW AND INCREASING INSTABILITY OF LAKE
SUPERIOR. WITH CYCLONIC FLOW AND COLD ADVECTION...TRENDED
CONSIDERABLY MORE CLOUDY WITH THE SKY COVER TONIGHT. STILL THINK
WILL SEE CLEARING SKIES AFTER MIDNIGHT OVER CENTRAL AND NORTHEAST
WISCONSIN AS MOISTURE IN THE COLUMN DRIES OUT. TEMPS THIS MORNING
OVER NORTHERN MINNESOTA WERE IN THE 32-34 DEGREE RANGE...WHICH WILL
BE THE AIRMASS ADVECTING INTO THE AREA TONIGHT. WITH NO CHANCE OF
DECOUPLING AND CLOUDS POTENTIALLY STICKING AROUND LONGER...HAVE
RAISED LOW TEMPS TOWARDS THE ECMWFBC GUIDANCE...WHICH IS USUALLY ONE
OF THE BETTER PERFORMING TEMP GUIDANCES. SINCE FROST IS A MINIMAL
CONCERN DUE TO WINDS REMAINING UP...HEADLINES ARE REALLY A FREEZE OR
NO FREEZE SCENARIO. WITH TEMPS ONLY BRIEFLY REACHING 32 DEGREES
LATE TONIGHT IN CENTRAL WISCONSIN...COORDINATION RESULTED IN A
DECISION TO GO WITH NO HEADLINES TONIGHT...BUT WILL STILL ADVISE
PEOPLE TO TAKE PRECAUTIONS WITH THEIR SENSITIVE PLANTS OVER CENTRAL
WISCONSIN IN THE HWO...IN CASE TEMPS DO FALL MORE THAN EXPECTED.
WILL GO WITH LOWS IN THE UPPER 20S NORTH...TO 32 DEGREES OVER
CENTRAL WISCONSIN...TO THE MID 30S NEAR LAKE MICHIGAN.
SUNDAY...LOW PRESSURE WILL MOVE FURTHER EAST INTO QUEBEC WHILE HIGH
PRESSURE BUILDS INTO THE REGION. THINK BROKEN CLOUD COVER WILL
CONTINUE TO RESIDE OVER NORTH-CENTRAL WISCONSIN TO START THE MORNING
WHICH SHOULD RETREAT TO THE NORTH. WITH DIURNAL HEATING
THOUGH...RATHER FLAT DIURNAL CU SHOULD DEVELOP BY LATE MORNING AND
THEN MIX OUT IN THE AFTERNOON. HIGHS TO TOP OUT IN THE MIDDLE 40S TO
LOWER 50S.
.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY
ISSUED AT 228 PM CDT SAT MAY 11 2013
MAIN FCST CONCERNS INCLUDE FREEZE HEADLINES FOR SUNDAY NIGHT...THE
POTENTIAL FOR SEVERE TSTMS LATE TUESDAY INTO TUESDAY NIGHT...AND
TEMPERATURES THROUGH THE PERIOD.
SFC HIGH PRESSURE WILL RESIDE OVER THE FORECAST AREA ON SUNDAY NIGHT.
CLEAR SKIES AND LIGHT/CALM WINDS WILL ALLOW TEMPS TO DROP BLO FREEZING
ACROSS ALL BUT THE LAKESHORE AREAS. WE HAVE NOT STARTED UP FROST/FREEZE
HEADLINES OVER NORTHERN WI YET...SO NO HEADLINES THERE DESPITE MIN TEMPS
IN THE LOW TO MID 20S. WILL KEEP THE FREEZE WATCH GOING ACROSS THE
SOUTHERN HALF OF THE CWA...AND WOULD ANTICIPATE THAT THIS WILL BE
UPGRADED A FREEZE WARNING WITH THE 4 AM SUNDAY FCST PACKAGE.
AN UPPER LEVEL RIDGE WILL BUILD OVER THE REGION MONDAY INTO TUESDAY...
WITH LOW-LEVEL WAA KICKING IN MONDAY INTO MONDAY NIGHT. THE WAA SURGE
WILL BRING INCREASING CLOUDS...WITH A CHANCE OF SHOWERS OVER OUR WSTRN
COUNTIES ON MONDAY...AND OVER THE ENTIRE CWA MONDAY NIGHT.
ON TUESDAY...A WARM FRONT IS EXPECTED TO LIFT NORTHWARD INTO CENTRAL
WI DURING THE AFTERNOON. TEMPERATURES WILL BE A TOUGH CALL...AS CLOUDS
AND EAST WINDS NORTH OF THE FRONT COULD HOLD READINGS IN THE 50S/60S
OVER THE LAKESHORE AND FAR NE WI...WHILE MIXING THROUGH 850 MB OVER
CENTRAL WI WOULD BE SUPPORTIVE OF HIGHS IN THE UPPER 80S/LOWER 90S
IN THE FAR SW PART OF THE CWA. NOT CONFIDENT ENOUGH TO GO WITH THAT
LARGE OF A GRADIENT OVER THE FORECAST AREA...BUT WILL HAVE UPPER 50S/
LOWER 60S NEAR THE LAKE...WITH INLAND LOCATIONS RANGING FROM THE UPPER
60S OVER FAR NE WI TO THE LOWER 80S IN CENTRAL WI.
WILL CARRY A SLGT CHC/CHANCE OF TSTMS NORTH OF THE WARM FRONT ON
TUESDAY...AS THE MODELS SHOW A SURGE OF INSTABILITY ARRIVING DURING
THE AFTERNOON...BUT ALSO SOME POTENTIAL CAPPING. AM CONCERNED ABOUT
THE POTENTIAL FOR SVR TSTMS TUESDAY NIGHT...AS THE WARM FRONT LIFTS
NORTH...FOLLOWED BY THE COLD FRONTAL PASSAGE OVERNIGHT. MODELS ARE
IN DECENT AGREEMENT ON MUCAPE INCREASING TO 1500-2000 J/KG...
ALONG WITH DEEP LAYER SHEAR OF 45-55 KNOTS...0-3 KM HELICITIES OF
300-500...AND MID-LEVEL LAPSE RATES INCREASING TO 7-7.5 C/KM. THE
GFS MODEL SEEMS TO DEPICT THIS BEST...WITH A BULLSEYE OF QPF OVER
THE NE HALF OF THE FORECAST AREA. WILL ADD A MENTION OF POSSIBLE
SVR TSTMS LATE TUESDAY INTO TUESDAY NIGHT TO THE HAZARDOUS WEATHER
OUTLOOK.
THE COLD FRONT IS EXPECTED TO SHIFT SOUTH OF THE AREA WEDNESDAY INTO
THURSDAY NIGHT...RESULTING IN A GENERAL LULL IN THE PCPN. THE FRONT
WILL LIFT BACK TO THE NORTH LATE IN THE WEEK...BRINGING THE CHANCE
OF TSTMS BACK INTO THE REGION ON FRI/SAT.
ALTHOUGH TEMPERATURES WILL START OFF ON THE COOL SIDE...THEY SHOULD
AVERAGE ABOVE NORMAL FROM TUESDAY THROUGH SATURDAY.
&&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 701 PM CDT SAT MAY 11 2013
A STRONG UPPER LEVEL DISTURBANCE WITH VERY COLD AIR
ALOFT WILL CONTINUE TO SLIDE OVER THE GREAT LAKES REGION.
INSTABILITY RAIN AND SNOW SHOWERS WILL LINGER INTO THE EVENING
BEFORE OR ENDING. MAINLY VFR CIGS EXPECTED TONIGHT INTO
SUNDAY. BUT THROUGH THE EVENING HOURS...SCATTERED MVFR CIGS AND
VSBYS WITH SNOW SHOWER ACTIVITY EXPECTED OVER MUCH OF NORTH
CENTRAL WISCONSIN.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZE WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY MORNING FOR
WIZ020-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......TDH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1212 PM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CDT FRI MAY 10 2013
MAIN FORECAST CONCERN IS WITH THE IMPACTS OF A COLD FRONT TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST INTO BRITISH COLUMBIA...A POTENT
SHORTWAVE TROUGH DROPPING INTO CENTRAL SASKATCHEWAN...AND A WEAK
SHORTWAVE TROUGH OVER CENTRAL WISCONSIN. THE LATTER SHORTWAVE TROUGH
WAS RESPONSIBLE FOR THE WET WEATHER YESTERDAY...WHICH LATEST RADAR
IMAGERY STILL SHOWS SCATTERED SHOWERS AND DRIZZLE OVER THE SOUTHEAST
HALF OF THE FORECAST AREA. CLOUDS ASSOCIATED WITH THE SHORTWAVE
ENCOMPASS MUCH OF THE FORECAST AREA...BUT HAVE CLEARED OUT ACROSS
NORTH DAKOTA INTO THE NORTHERN 2/3 OF MINNESOTA AND NORTHWEST WI.
00Z BIS AND ABR SOUNDINGS WERE VERY DRY BELOW 700MB WITH DEWPOINT
DEPRESSIONS OF 15C OR GREATER. THIS DRY AIR WAS ASSOCIATED WITH A
SURFACE RIDGE OF HIGH PRESSURE. A TIGHT PRESSURE GRADIENT AHEAD OF
THE HIGH AND LOW PRESSURE MOVING THROUGH NORTHERN ILLINOIS HAS
RESULTED IN SOME GUSTY NORTHEAST WINDS ACROSS THE FORECAST AREA.
COOLER AIR TOO WITH THE HIGH PRESSURE RIDGE...REFLECTED BY 850MB
TEMPS AT 00Z OF 5-7C FROM BIS TO MPX...COMPARED TO 10C AT DVN. TO
THE NORTHWEST...BEHIND THE POTENT SHORTWAVE TROUGH...MUCH COLDER
AIR EXISTS. -2C 850MB TEMPS WERE OBSERVED AT 00Z OVER NORTHERN
ALBERTA. THE COLD FRONT ASSOCIATED WITH THE TROUGH WAS IN SOUTHEAST
SASKATCHEWAN.
THE HIGH PRESSURE RIDGE AND ITS DRY AIR ARE FORECAST TO MOVE INTO
THE CWA THROUGH THE DAY...WITH THE RIDGE OVERHEAD AT 00Z. THUS...WE
WILL SEE GRADUAL CLEARING NORTHWEST TO SOUTHEAST THROUGH THE DAY.
MAY STILL HAVE TO CONTEND WITH SOME LINGERING SHOWERS TOO IN THE
SOUTHEAST SECTION OF THE FORECAST AREA UNTIL 15Z. TEMPERATURES ARE
LIKELY TO STRUGGLE TO RISE THIS MORNING WITH COLD ADVECTION AND
CLOUDS IN PLACE...BUT SHOULD BE ABLE TO CLIMB INTO THE LOW TO MID
60S BY LATE IN THE DAY WITH THE SUN AND 850MB TEMPS OF 4-5C.
MODELS ARE IN GOOD AGREEMENT TAKING THE POTENT SHORTWAVE TROUGH
OVER CENTRAL SASKATCHEWAN INTO NORTHWEST ONTARIO TONIGHT...WITH
ANOTHER STRONG SHORTWAVE DIGGING IN BEHIND IT INTO CENTRAL MINNESOTA
BY 12Z SATURDAY. THE 500MB HEIGHT FALLS ARE QUITE IMPRESSIVE BETWEEN
00-12Z...FROM AROUND 100 METERS ALONG I-90 TO ALMOST 200 METERS OVER
WESTERN LAKE SUPERIOR. NEEDLESS TO SAY...PLENTY OF DYNAMIC FORCING.
ONE HUGE PROBLEM IS THE LACK OF MOISTURE... ESPECIALLY AHEAD OF THE
TROUGH PER THE 00Z BIS SOUNDING. THUS...NO PRECIPITATION WILL OCCUR
AHEAD OF THE COLD FRONT ACCOMPANYING THE TROUGH...WHICH IS PROGGED
TO CROSS THE AREA BETWEEN 06-12Z. IF PRECIPITATION OCCURS...IT HAS
TO OCCUR THEN POST-FRONTAL...IN THE COOLER AIR. CROSS-SECTIONS SHOW
A FAIRLY STRONG LOW LEVEL FRONTOGENESIS-FRONTOLYSIS COUPLET...ALONG
WITH SOME NEGATIVE EPV BEING INGESTED INTO THIS CIRCULATION. WITH
ALL THE FORCING PRESENT...HAVE TO IMAGINE A NARROW BAND OF SHOWERS
COMING THROUGH BEHIND THE FRONT. THERE MAY EVEN BE A RUMBLE OR TWO
OF THUNDER GIVEN THE NEGATIVE EPV SIGNAL...BUT THE CHANCE AND
COVERAGE IS TOO LOW TO MENTION. EXPECT WINDS TOO TO RAPIDLY INCREASE
OUT OF THE NORTHWEST BEHIND THE FRONT...AIDED BY ISALLOBARIC
FORCING. SOME PLACES...LIKE ROCHESTER AND DODGE CENTER...COULD GUST
CLOSE TO WIND ADVISORY...ESPECIALLY WITH THE SHOWERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 327 AM CDT FRI MAY 10 2013
DEEP TROUGHING IS PROGGED TO PERSIST OVER THE GREAT LAKES MUCH OF
THE WEEKEND...RESULTING FROM THE POTENT SHORTWAVE TROUGH DIGGING
TOWARDS THE AREA TONIGHT. 500MB STANDARDIZED ANOMALIES ARE 1.5-2
BELOW NORMAL ALONG WITH 850MB ANOMALIES OF 2 BELOW NORMAL. THESE LOW
ANOMALIES RESULT IN A VARIETY OF ISSUES:
1. TEMPERATURES. CHILLY HIGHS AND LOWS ARE LIKELY...AND COULD GET
CLOSE TO RECORDS SOLELY BASED ON THE 850MB ANOMALIES. LA CROSSE
RECORD LOWS ARE AROUND 30 WHILE ROCHESTER IS AROUND 26. THE BIGGEST
PROBLEM WITH TEMPERATURES ARE THE WINDS. CONTINUOUS COLD ADVECTION
THROUGH SATURDAY NIGHT WILL HELP KEEP THE BOUNDARY LAYER MIXED...AND
WITH 925MB WINDS STILL AT 20-25 KT AT 12Z SUNDAY...EXPECTING
DIFFICULT CONDITIONS TO DECOUPLE. BETTER SHOT OF DECOUPLING TAKES
PLACE SUNDAY EVENING...BUT WARM ADVECTION TAKES HOLD AFTER
MIDNIGHT. FOR NOW HAVE TAKEN A BLEND OF MOS AND RAW MODEL GUIDANCE
FOR HIGHS AND LOWS...GIVEN THE UNCERTAINTY ON DECOUPLING.
2. WINDS...STRONG SUBSIDENCE FLOWS INTO THE AREA ON SATURDAY WILL
COMBINE WITH LOW LEVEL UNIDIRECTIONAL NORTHWEST FLOW...THE STRONG
MIXING FROM THE MAY SUN...AND COLD ADVECTION TO RESULT IN A BLUSTERY
DAY. WE COULD MIX TO 775 MB OR HIGHER. MOMENTUM TRANSFER OF THE
WINDS AT THAT LEVEL OF 40-45 KT RESULTS IN GUSTS OF 30-35 KT AT THE
SURFACE...JUST BELOW ADVISORY CRITERIA. WINDS SLOWLY DIMINISH
SATURDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE
PLAINS.
3. FROST/FREEZE. CONNECTING WITH THE TEMPERATURES AND WINDS ABOVE...
FROST LOOKS VERY DIFFICULT TO FORM SATURDAY NIGHT. ADDITIONALLY...
RELATIVE HUMIDITIES MAY NOT EXCEED 80 PERCENT DUE TO DRY ADVECTION.
IF ANYTHING...THE CONCERN WOULD COME FROM A FREEZE DUE TO THE
TEMPERATURES...IF THEY FALL BELOW FREEZING. BETTER SHOT OF FROST
WOULD COME SUNDAY NIGHT...DEPENDING ON WHEN HIGH CLOUDS AND THE WARM
AIR SPREADS IN. FROST LOOKS MOST LIKELY IN CENTRAL WISCONSIN.
4. PRECIPITATION...COLD POOL OF 500MB TEMPS OF -30C LOOKS TO CROSS
TAYLOR COUNTY MID-DAY SATURDAY. DAYTIME MIXING COMBINED WITH THE
MOISTURE WITH THIS COLD POOL COULD GENERATE A FEW SHOWERS ACROSS
TAYLOR/CLARK COUNTIES. HAVE KEPT 20 PERCENT CHANCES GOING FOR THESE.
OTHERWISE...DRY CONDITIONS EXPECTED TO PREVAIL.
FOR NEXT WEEK...THE BIG HIGHLIGHT IS TUESDAY AND WEDNESDAY WITH A
CONSISTENTLY SHOWN STRONG SURGE OF WARM AIR. THERE IS VERY STRONG
MODEL AGREEMENT OF TROUGHING COMING INTO THE PACIFIC NORTHWEST EARLY
NEXT WEEK...SHOVING A RIDGE TOWARDS THE FORECAST AREA. A LOW
POTENTIAL EXISTS FOR SOME SHOWERS AND THUNDERSTORMS AS THE RIDGE
APPROACHES MONDAY AFTERNOON INTO MONDAY NIGHT. HEADING INTO
TUESDAY...850MB STANDARDIZED ANOMALIES JUMP TO 2-2.5 ABOVE...
SUGGESTING POTENTIAL RECORD HIGHS. THERE ARE TWO ISSUES ON TUESDAY
TO CONTEND WITH...TIMING OF THE SURFACE WARM FRONT AND HOW DRY THE
AIR IS IN THE WAKE OF THE FRONT. THE 09.12Z/10.00Z GFS WERE IN GREAT
AGREEMENT PUSHING THE WARM FRONT THROUGH THE AREA ON TUESDAY...
LIKELY RESULTING IN HIGHS IN THE 80S TO POSSIBLY LOW 90S.
HOWEVER...THE 10.00Z ECMWF/CANADIAN ONLY GET THE WARM FRONT TO THE
MISSISSIPPI RIVER. WITH 850MB TEMPS OF 20C+ IN THE WAKE OF THE
FRONT...TIMING OF THE FRONT IS CRITICAL. ON THE MOISTURE SIDE...THE
GFS AND ECMWF WANT TO BRING DEWPOINTS UP INTO THE 60S...BUT THIS
SEEMS WAY TOO HIGH GIVEN THE LACK OF CORN CROPS TO THE SOUTH AND THE
WARM SURGE BEING OF ROCKIES ORIGIN. THUS...DEEPER MIXING IS LIKELY
BEHIND THE FRONT. NEXT CONCERN IS WHEN DOES A COLD FRONT COME
THROUGH. THE 10.00Z ECMWF/CANADIAN REALLY SLOWED THIS DOWN...NOT
CROSSING TIL THURSDAY. IF THIS COMES TRUE...HIGHS WEDNESDAY
COULD TOUCH 90. ON THE OTHER HAND...A FASTER FRONT FROM THE 10.00Z
GFS WOULD KEEP HIGHS IN THE 70S. SPLIT THE DIFFERENCE FOR HIGHS ON
WEDNESDAY FOR NOW. ALSO...MAINTAINED A 20-30 PERCENT CHANCE FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH THURSDAY FOR THE
FRONT...WITH WEDNESDAYS CHANCES IN CASE THE FRONT ENDS UP BEING
FASTER.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1211 PM CDT FRI MAY 10 2013
CLOUDS BEHIND THE COLD FRONT HAVE CLEARED BOTH TAF SITES FOR THE
MOST PART. ONE LAST AREA OF CLOUDS COULD ROTATE BACK ACROSS KLSE
EARLY THIS AFTERNOON FOR A SHORT PERIOD OF SOME VFR CEILINGS.
AFTER THAT...WEAK HIGH PRESSURE WILL QUICKLY MOVE ACROSS THIS
EVENING FOR A PERIOD OF VFR WEATHER. THE NEXT COLD FRONT IS
ALREADY MOVING SOUTHEAST ACROSS THE DAKOTAS. BASED ON THE 10.12Z
NAM AND 10.06Z HI-RES ARW...THIS FRONT WILL MOVE QUICKLY ACROSS
BOTH TAF SITES IN THE 09Z TO 12Z WINDOW. THE BEST FORCING WITH THE
COLD FRONT APPEARS TO BE NORTHEAST OF THE TAF SITES SO MAINLY
EXPECTING THE POSSIBILITY OF SCATTERED SHOWERS ALONG AND BEHIND
THE FRONT FOR THE TAF SITES. HAVE SHOWN A THREE HOUR WINDOW IN A
TEMPO GROUP WHERE THE BEST CHANCE FOR SOME SHOWERS SHOULD BE ALONG
WITH MVFR CEILINGS. THE OTHER ISSUE BEHIND THE FRONT WILL BE THE
NORTHWEST WINDS. STRONG LOW LEVEL LAPSE RATES OF 7-9 C/KM DEVELOP
QUICKLY BELOW 750 MB ONCE THE FRONT PASSES THROUGH. THIS WILL
ALLOW FOR DEEP MIXING TO DEVELOP TO PRODUCE GUSTY NORTHWEST WINDS.
SUSTAINED SPEEDS SHOULD INCREASE TO AROUND 20 KNOTS BY MID MORNING
WITH GUSTS TO AROUND 30 KNOTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...04
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
614 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CDT FRI MAY 10 2013
MAIN FORECAST CONCERN IS WITH THE IMPACTS OF A COLD FRONT TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST INTO BRITISH COLUMBIA...A POTENT
SHORTWAVE TROUGH DROPPING INTO CENTRAL SASKATCHEWAN...AND A WEAK
SHORTWAVE TROUGH OVER CENTRAL WISCONSIN. THE LATTER SHORTWAVE TROUGH
WAS RESPONSIBLE FOR THE WET WEATHER YESTERDAY...WHICH LATEST RADAR
IMAGERY STILL SHOWS SCATTERED SHOWERS AND DRIZZLE OVER THE SOUTHEAST
HALF OF THE FORECAST AREA. CLOUDS ASSOCIATED WITH THE SHORTWAVE
ENCOMPASS MUCH OF THE FORECAST AREA...BUT HAVE CLEARED OUT ACROSS
NORTH DAKOTA INTO THE NORTHERN 2/3 OF MINNESOTA AND NORTHWEST WI.
00Z BIS AND ABR SOUNDINGS WERE VERY DRY BELOW 700MB WITH DEWPOINT
DEPRESSIONS OF 15C OR GREATER. THIS DRY AIR WAS ASSOCIATED WITH A
SURFACE RIDGE OF HIGH PRESSURE. A TIGHT PRESSURE GRADIENT AHEAD OF
THE HIGH AND LOW PRESSURE MOVING THROUGH NORTHERN ILLINOIS HAS
RESULTED IN SOME GUSTY NORTHEAST WINDS ACROSS THE FORECAST AREA.
COOLER AIR TOO WITH THE HIGH PRESSURE RIDGE...REFLECTED BY 850MB
TEMPS AT 00Z OF 5-7C FROM BIS TO MPX...COMPARED TO 10C AT DVN. TO
THE NORTHWEST...BEHIND THE POTENT SHORTWAVE TROUGH...MUCH COLDER
AIR EXISTS. -2C 850MB TEMPS WERE OBSERVED AT 00Z OVER NORTHERN
ALBERTA. THE COLD FRONT ASSOCIATED WITH THE TROUGH WAS IN SOUTHEAST
SASKATCHEWAN.
THE HIGH PRESSURE RIDGE AND ITS DRY AIR ARE FORECAST TO MOVE INTO
THE CWA THROUGH THE DAY...WITH THE RIDGE OVERHEAD AT 00Z. THUS...WE
WILL SEE GRADUAL CLEARING NORTHWEST TO SOUTHEAST THROUGH THE DAY.
MAY STILL HAVE TO CONTEND WITH SOME LINGERING SHOWERS TOO IN THE
SOUTHEAST SECTION OF THE FORECAST AREA UNTIL 15Z. TEMPERATURES ARE
LIKELY TO STRUGGLE TO RISE THIS MORNING WITH COLD ADVECTION AND
CLOUDS IN PLACE...BUT SHOULD BE ABLE TO CLIMB INTO THE LOW TO MID
60S BY LATE IN THE DAY WITH THE SUN AND 850MB TEMPS OF 4-5C.
MODELS ARE IN GOOD AGREEMENT TAKING THE POTENT SHORTWAVE TROUGH
OVER CENTRAL SASKATCHEWAN INTO NORTHWEST ONTARIO TONIGHT...WITH
ANOTHER STRONG SHORTWAVE DIGGING IN BEHIND IT INTO CENTRAL MINNESOTA
BY 12Z SATURDAY. THE 500MB HEIGHT FALLS ARE QUITE IMPRESSIVE BETWEEN
00-12Z...FROM AROUND 100 METERS ALONG I-90 TO ALMOST 200 METERS OVER
WESTERN LAKE SUPERIOR. NEEDLESS TO SAY...PLENTY OF DYNAMIC FORCING.
ONE HUGE PROBLEM IS THE LACK OF MOISTURE... ESPECIALLY AHEAD OF THE
TROUGH PER THE 00Z BIS SOUNDING. THUS...NO PRECIPITATION WILL OCCUR
AHEAD OF THE COLD FRONT ACCOMPANYING THE TROUGH...WHICH IS PROGGED
TO CROSS THE AREA BETWEEN 06-12Z. IF PRECIPITATION OCCURS...IT HAS
TO OCCUR THEN POST-FRONTAL...IN THE COOLER AIR. CROSS-SECTIONS SHOW
A FAIRLY STRONG LOW LEVEL FRONTOGENESIS-FRONTOLYSIS COUPLET...ALONG
WITH SOME NEGATIVE EPV BEING INGESTED INTO THIS CIRCULATION. WITH
ALL THE FORCING PRESENT...HAVE TO IMAGINE A NARROW BAND OF SHOWERS
COMING THROUGH BEHIND THE FRONT. THERE MAY EVEN BE A RUMBLE OR TWO
OF THUNDER GIVEN THE NEGATIVE EPV SIGNAL...BUT THE CHANCE AND
COVERAGE IS TOO LOW TO MENTION. EXPECT WINDS TOO TO RAPIDLY INCREASE
OUT OF THE NORTHWEST BEHIND THE FRONT...AIDED BY ISALLOBARIC
FORCING. SOME PLACES...LIKE ROCHESTER AND DODGE CENTER...COULD GUST
CLOSE TO WIND ADVISORY...ESPECIALLY WITH THE SHOWERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 327 AM CDT FRI MAY 10 2013
DEEP TROUGHING IS PROGGED TO PERSIST OVER THE GREAT LAKES MUCH OF
THE WEEKEND...RESULTING FROM THE POTENT SHORTWAVE TROUGH DIGGING
TOWARDS THE AREA TONIGHT. 500MB STANDARDIZED ANOMALIES ARE 1.5-2
BELOW NORMAL ALONG WITH 850MB ANOMALIES OF 2 BELOW NORMAL. THESE LOW
ANOMALIES RESULT IN A VARIETY OF ISSUES:
1. TEMPERATURES. CHILLY HIGHS AND LOWS ARE LIKELY...AND COULD GET
CLOSE TO RECORDS SOLELY BASED ON THE 850MB ANOMALIES. LA CROSSE
RECORD LOWS ARE AROUND 30 WHILE ROCHESTER IS AROUND 26. THE BIGGEST
PROBLEM WITH TEMPERATURES ARE THE WINDS. CONTINUOUS COLD ADVECTION
THROUGH SATURDAY NIGHT WILL HELP KEEP THE BOUNDARY LAYER MIXED...AND
WITH 925MB WINDS STILL AT 20-25 KT AT 12Z SUNDAY...EXPECTING
DIFFICULT CONDITIONS TO DECOUPLE. BETTER SHOT OF DECOUPLING TAKES
PLACE SUNDAY EVENING...BUT WARM ADVECTION TAKES HOLD AFTER
MIDNIGHT. FOR NOW HAVE TAKEN A BLEND OF MOS AND RAW MODEL GUIDANCE
FOR HIGHS AND LOWS...GIVEN THE UNCERTAINTY ON DECOUPLING.
2. WINDS...STRONG SUBSIDENCE FLOWS INTO THE AREA ON SATURDAY WILL
COMBINE WITH LOW LEVEL UNIDIRECTIONAL NORTHWEST FLOW...THE STRONG
MIXING FROM THE MAY SUN...AND COLD ADVECTION TO RESULT IN A BLUSTERY
DAY. WE COULD MIX TO 775 MB OR HIGHER. MOMENTUM TRANSFER OF THE
WINDS AT THAT LEVEL OF 40-45 KT RESULTS IN GUSTS OF 30-35 KT AT THE
SURFACE...JUST BELOW ADVISORY CRITERIA. WINDS SLOWLY DIMINISH
SATURDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE
PLAINS.
3. FROST/FREEZE. CONNECTING WITH THE TEMPERATURES AND WINDS ABOVE...
FROST LOOKS VERY DIFFICULT TO FORM SATURDAY NIGHT. ADDITIONALLY...
RELATIVE HUMIDITIES MAY NOT EXCEED 80 PERCENT DUE TO DRY ADVECTION.
IF ANYTHING...THE CONCERN WOULD COME FROM A FREEZE DUE TO THE
TEMPERATURES...IF THEY FALL BELOW FREEZING. BETTER SHOT OF FROST
WOULD COME SUNDAY NIGHT...DEPENDING ON WHEN HIGH CLOUDS AND THE WARM
AIR SPREADS IN. FROST LOOKS MOST LIKELY IN CENTRAL WISCONSIN.
4. PRECIPITATION...COLD POOL OF 500MB TEMPS OF -30C LOOKS TO CROSS
TAYLOR COUNTY MID-DAY SATURDAY. DAYTIME MIXING COMBINED WITH THE
MOISTURE WITH THIS COLD POOL COULD GENERATE A FEW SHOWERS ACROSS
TAYLOR/CLARK COUNTIES. HAVE KEPT 20 PERCENT CHANCES GOING FOR THESE.
OTHERWISE...DRY CONDITIONS EXPECTED TO PREVAIL.
FOR NEXT WEEK...THE BIG HIGHLIGHT IS TUESDAY AND WEDNESDAY WITH A
CONSISTENTLY SHOWN STRONG SURGE OF WARM AIR. THERE IS VERY STRONG
MODEL AGREEMENT OF TROUGHING COMING INTO THE PACIFIC NORTHWEST EARLY
NEXT WEEK...SHOVING A RIDGE TOWARDS THE FORECAST AREA. A LOW
POTENTIAL EXISTS FOR SOME SHOWERS AND THUNDERSTORMS AS THE RIDGE
APPROACHES MONDAY AFTERNOON INTO MONDAY NIGHT. HEADING INTO
TUESDAY...850MB STANDARDIZED ANOMALIES JUMP TO 2-2.5 ABOVE...
SUGGESTING POTENTIAL RECORD HIGHS. THERE ARE TWO ISSUES ON TUESDAY
TO CONTEND WITH...TIMING OF THE SURFACE WARM FRONT AND HOW DRY THE
AIR IS IN THE WAKE OF THE FRONT. THE 09.12Z/10.00Z GFS WERE IN GREAT
AGREEMENT PUSHING THE WARM FRONT THROUGH THE AREA ON TUESDAY...
LIKELY RESULTING IN HIGHS IN THE 80S TO POSSIBLY LOW 90S.
HOWEVER...THE 10.00Z ECMWF/CANADIAN ONLY GET THE WARM FRONT TO THE
MISSISSIPPI RIVER. WITH 850MB TEMPS OF 20C+ IN THE WAKE OF THE
FRONT...TIMING OF THE FRONT IS CRITICAL. ON THE MOISTURE SIDE...THE
GFS AND ECMWF WANT TO BRING DEWPOINTS UP INTO THE 60S...BUT THIS
SEEMS WAY TOO HIGH GIVEN THE LACK OF CORN CROPS TO THE SOUTH AND THE
WARM SURGE BEING OF ROCKIES ORIGIN. THUS...DEEPER MIXING IS LIKELY
BEHIND THE FRONT. NEXT CONCERN IS WHEN DOES A COLD FRONT COME
THROUGH. THE 10.00Z ECMWF/CANADIAN REALLY SLOWED THIS DOWN...NOT
CROSSING TIL THURSDAY. IF THIS COMES TRUE...HIGHS WEDNESDAY
COULD TOUCH 90. ON THE OTHER HAND...A FASTER FRONT FROM THE 10.00Z
GFS WOULD KEEP HIGHS IN THE 70S. SPLIT THE DIFFERENCE FOR HIGHS ON
WEDNESDAY FOR NOW. ALSO...MAINTAINED A 20-30 PERCENT CHANCE FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH THURSDAY FOR THE
FRONT...WITH WEDNESDAYS CHANCES IN CASE THE FRONT ENDS UP BEING
FASTER.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 614 AM CDT FRI MAY 10 2013
RADAR SHOWING REMNANTS OF RAIN MOVING OFF TO THE SOUTHEAST WITH
MVFR/VFR CLOUD COVERING MUCH OF THE FORECAST AREA. CLOUDS WILL BE
ON A SLOW DIMINISHING TREND FROM NORTHWEST TO SOUTHEAST ACROSS THE
AREA AS HIGH PRESSURE BUILDS IN FROM ONTARIO AND MINNESOTA. BY
THIS EVENING...SKIES EXPECTED TO BE MOSTLY CLEAR WITH INCREASING
CLOUDS AGAIN AFTER MIDNIGHT AHEAD OF A COLD FRONT DROPPING INTO
THE REGION. SHOWERS ARE EXPECTED WITH THE FRONTAL PASSAGE WITH
CIGS FALLING INTO MVFR RANGE BY 10Z.
LOOKING FURTHER...GUSTY NORTHWEST WINDS WILL FOLLOW THE FRONTAL
PASSAGE SATURDAY. EXPECT WINDS IN THE 15 TO 25 KT RANGE WITH GUSTS
AROUND 35KT...ESPECIALLY ACROSS THE HIGHER/OPEN TERRAIN AREAS OF
SOUTHEAST MN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
327 AM CDT FRI MAY 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 327 AM CDT FRI MAY 10 2013
MAIN FORECAST CONCERN IS WITH THE IMPACTS OF A COLD FRONT TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING ALONG THE WEST COAST INTO BRITISH COLUMBIA...A POTENT
SHORTWAVE TROUGH DROPPING INTO CENTRAL SASKATCHEWAN...AND A WEAK
SHORTWAVE TROUGH OVER CENTRAL WISCONSIN. THE LATTER SHORTWAVE TROUGH
WAS RESPONSIBLE FOR THE WET WEATHER YESTERDAY...WHICH LATEST RADAR
IMAGERY STILL SHOWS SCATTERED SHOWERS AND DRIZZLE OVER THE SOUTHEAST
HALF OF THE FORECAST AREA. CLOUDS ASSOCIATED WITH THE SHORTWAVE
ENCOMPASS MUCH OF THE FORECAST AREA...BUT HAVE CLEARED OUT ACROSS
NORTH DAKOTA INTO THE NORTHERN 2/3 OF MINNESOTA AND NORTHWEST WI.
00Z BIS AND ABR SOUNDINGS WERE VERY DRY BELOW 700MB WITH DEWPOINT
DEPRESSIONS OF 15C OR GREATER. THIS DRY AIR WAS ASSOCIATED WITH A
SURFACE RIDGE OF HIGH PRESSURE. A TIGHT PRESSURE GRADIENT AHEAD OF
THE HIGH AND LOW PRESSURE MOVING THROUGH NORTHERN ILLINOIS HAS
RESULTED IN SOME GUSTY NORTHEAST WINDS ACROSS THE FORECAST AREA.
COOLER AIR TOO WITH THE HIGH PRESSURE RIDGE...REFLECTED BY 850MB
TEMPS AT 00Z OF 5-7C FROM BIS TO MPX...COMPARED TO 10C AT DVN. TO
THE NORTHWEST...BEHIND THE POTENT SHORTWAVE TROUGH...MUCH COLDER
AIR EXISTS. -2C 850MB TEMPS WERE OBSERVED AT 00Z OVER NORTHERN
ALBERTA. THE COLD FRONT ASSOCIATED WITH THE TROUGH WAS IN SOUTHEAST
SASKATCHEWAN.
THE HIGH PRESSURE RIDGE AND ITS DRY AIR ARE FORECAST TO MOVE INTO
THE CWA THROUGH THE DAY...WITH THE RIDGE OVERHEAD AT 00Z. THUS...WE
WILL SEE GRADUAL CLEARING NORTHWEST TO SOUTHEAST THROUGH THE DAY.
MAY STILL HAVE TO CONTEND WITH SOME LINGERING SHOWERS TOO IN THE
SOUTHEAST SECTION OF THE FORECAST AREA UNTIL 15Z. TEMPERATURES ARE
LIKELY TO STRUGGLE TO RISE THIS MORNING WITH COLD ADVECTION AND
CLOUDS IN PLACE...BUT SHOULD BE ABLE TO CLIMB INTO THE LOW TO MID
60S BY LATE IN THE DAY WITH THE SUN AND 850MB TEMPS OF 4-5C.
MODELS ARE IN GOOD AGREEMENT TAKING THE POTENT SHORTWAVE TROUGH
OVER CENTRAL SASKATCHEWAN INTO NORTHWEST ONTARIO TONIGHT...WITH
ANOTHER STRONG SHORTWAVE DIGGING IN BEHIND IT INTO CENTRAL MINNESOTA
BY 12Z SATURDAY. THE 500MB HEIGHT FALLS ARE QUITE IMPRESSIVE BETWEEN
00-12Z...FROM AROUND 100 METERS ALONG I-90 TO ALMOST 200 METERS OVER
WESTERN LAKE SUPERIOR. NEEDLESS TO SAY...PLENTY OF DYNAMIC FORCING.
ONE HUGE PROBLEM IS THE LACK OF MOISTURE... ESPECIALLY AHEAD OF THE
TROUGH PER THE 00Z BIS SOUNDING. THUS...NO PRECIPITATION WILL OCCUR
AHEAD OF THE COLD FRONT ACCOMPANYING THE TROUGH...WHICH IS PROGGED
TO CROSS THE AREA BETWEEN 06-12Z. IF PRECIPITATION OCCURS...IT HAS
TO OCCUR THEN POST-FRONTAL...IN THE COOLER AIR. CROSS-SECTIONS SHOW
A FAIRLY STRONG LOW LEVEL FRONTOGENESIS-FRONTOLYSIS COUPLET...ALONG
WITH SOME NEGATIVE EPV BEING INGESTED INTO THIS CIRCULATION. WITH
ALL THE FORCING PRESENT...HAVE TO IMAGINE A NARROW BAND OF SHOWERS
COMING THROUGH BEHIND THE FRONT. THERE MAY EVEN BE A RUMBLE OR TWO
OF THUNDER GIVEN THE NEGATIVE EPV SIGNAL...BUT THE CHANCE AND
COVERAGE IS TOO LOW TO MENTION. EXPECT WINDS TOO TO RAPIDLY INCREASE
OUT OF THE NORTHWEST BEHIND THE FRONT...AIDED BY ISALLOBARIC
FORCING. SOME PLACES...LIKE ROCHESTER AND DODGE CENTER...COULD GUST
CLOSE TO WIND ADVISORY...ESPECIALLY WITH THE SHOWERS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 327 AM CDT FRI MAY 10 2013
DEEP TROUGHING IS PROGGED TO PERSIST OVER THE GREAT LAKES MUCH OF
THE WEEKEND...RESULTING FROM THE POTENT SHORTWAVE TROUGH DIGGING
TOWARDS THE AREA TONIGHT. 500MB STANDARDIZED ANOMALIES ARE 1.5-2
BELOW NORMAL ALONG WITH 850MB ANOMALIES OF 2 BELOW NORMAL. THESE LOW
ANOMALIES RESULT IN A VARIETY OF ISSUES:
1. TEMPERATURES. CHILLY HIGHS AND LOWS ARE LIKELY...AND COULD GET
CLOSE TO RECORDS SOLELY BASED ON THE 850MB ANOMALIES. LA CROSSE
RECORD LOWS ARE AROUND 30 WHILE ROCHESTER IS AROUND 26. THE BIGGEST
PROBLEM WITH TEMPERATURES ARE THE WINDS. CONTINUOUS COLD ADVECTION
THROUGH SATURDAY NIGHT WILL HELP KEEP THE BOUNDARY LAYER MIXED...AND
WITH 925MB WINDS STILL AT 20-25 KT AT 12Z SUNDAY...EXPECTING
DIFFICULT CONDITIONS TO DECOUPLE. BETTER SHOT OF DECOUPLING TAKES
PLACE SUNDAY EVENING...BUT WARM ADVECTION TAKES HOLD AFTER
MIDNIGHT. FOR NOW HAVE TAKEN A BLEND OF MOS AND RAW MODEL GUIDANCE
FOR HIGHS AND LOWS...GIVEN THE UNCERTAINTY ON DECOUPLING.
2. WINDS...STRONG SUBSIDENCE FLOWS INTO THE AREA ON SATURDAY WILL
COMBINE WITH LOW LEVEL UNIDIRECTIONAL NORTHWEST FLOW...THE STRONG
MIXING FROM THE MAY SUN...AND COLD ADVECTION TO RESULT IN A BLUSTERY
DAY. WE COULD MIX TO 775 MB OR HIGHER. MOMENTUM TRANSFER OF THE
WINDS AT THAT LEVEL OF 40-45 KT RESULTS IN GUSTS OF 30-35 KT AT THE
SURFACE...JUST BELOW ADVISORY CRITERIA. WINDS SLOWLY DIMINISH
SATURDAY NIGHT THROUGH SUNDAY AS HIGH PRESSURE BUILDS IN FROM THE
PLAINS.
3. FROST/FREEZE. CONNECTING WITH THE TEMPERATURES AND WINDS ABOVE...
FROST LOOKS VERY DIFFICULT TO FORM SATURDAY NIGHT. ADDITIONALLY...
RELATIVE HUMIDITIES MAY NOT EXCEED 80 PERCENT DUE TO DRY ADVECTION.
IF ANYTHING...THE CONCERN WOULD COME FROM A FREEZE DUE TO THE
TEMPERATURES...IF THEY FALL BELOW FREEZING. BETTER SHOT OF FROST
WOULD COME SUNDAY NIGHT...DEPENDING ON WHEN HIGH CLOUDS AND THE WARM
AIR SPREADS IN. FROST LOOKS MOST LIKELY IN CENTRAL WISCONSIN.
4. PRECIPITATION...COLD POOL OF 500MB TEMPS OF -30C LOOKS TO CROSS
TAYLOR COUNTY MID-DAY SATURDAY. DAYTIME MIXING COMBINED WITH THE
MOISTURE WITH THIS COLD POOL COULD GENERATE A FEW SHOWERS ACROSS
TAYLOR/CLARK COUNTIES. HAVE KEPT 20 PERCENT CHANCES GOING FOR THESE.
OTHERWISE...DRY CONDITIONS EXPECTED TO PREVAIL.
FOR NEXT WEEK...THE BIG HIGHLIGHT IS TUESDAY AND WEDNESDAY WITH A
CONSISTENTLY SHOWN STRONG SURGE OF WARM AIR. THERE IS VERY STRONG
MODEL AGREEMENT OF TROUGHING COMING INTO THE PACIFIC NORTHWEST EARLY
NEXT WEEK...SHOVING A RIDGE TOWARDS THE FORECAST AREA. A LOW
POTENTIAL EXISTS FOR SOME SHOWERS AND THUNDERSTORMS AS THE RIDGE
APPROACHES MONDAY AFTERNOON INTO MONDAY NIGHT. HEADING INTO
TUESDAY...850MB STANDARDIZED ANOMALIES JUMP TO 2-2.5 ABOVE...
SUGGESTING POTENTIAL RECORD HIGHS. THERE ARE TWO ISSUES ON TUESDAY
TO CONTEND WITH...TIMING OF THE SURFACE WARM FRONT AND HOW DRY THE
AIR IS IN THE WAKE OF THE FRONT. THE 09.12Z/10.00Z GFS WERE IN GREAT
AGREEMENT PUSHING THE WARM FRONT THROUGH THE AREA ON TUESDAY...
LIKELY RESULTING IN HIGHS IN THE 80S TO POSSIBLY LOW 90S.
HOWEVER...THE 10.00Z ECMWF/CANADIAN ONLY GET THE WARM FRONT TO THE
MISSISSIPPI RIVER. WITH 850MB TEMPS OF 20C+ IN THE WAKE OF THE
FRONT...TIMING OF THE FRONT IS CRITICAL. ON THE MOISTURE SIDE...THE
GFS AND ECMWF WANT TO BRING DEWPOINTS UP INTO THE 60S...BUT THIS
SEEMS WAY TOO HIGH GIVEN THE LACK OF CORN CROPS TO THE SOUTH AND THE
WARM SURGE BEING OF ROCKIES ORIGIN. THUS...DEEPER MIXING IS LIKELY
BEHIND THE FRONT. NEXT CONCERN IS WHEN DOES A COLD FRONT COME
THROUGH. THE 10.00Z ECMWF/CANADIAN REALLY SLOWED THIS DOWN...NOT
CROSSING TIL THURSDAY. IF THIS COMES TRUE...HIGHS WEDNESDAY
COULD TOUCH 90. ON THE OTHER HAND...A FASTER FRONT FROM THE 10.00Z
GFS WOULD KEEP HIGHS IN THE 70S. SPLIT THE DIFFERENCE FOR HIGHS ON
WEDNESDAY FOR NOW. ALSO...MAINTAINED A 20-30 PERCENT CHANCE FOR
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH THURSDAY FOR THE
FRONT...WITH WEDNESDAYS CHANCES IN CASE THE FRONT ENDS UP BEING
FASTER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1100 PM CDT THU MAY 9 2013
RAIN CONTINUES TO FALL NORTH OF AN AREA OF LOW PRESSURE...WHICH WAS
TRACKING WEST TO EAST ACROSS NORTHWEST IL. A FEW TS JUST NORTH OF
THE LOW...BUT INSTABILITY STAYS SOUTH...AND DON/T SEE A TS THREAT AT
KRST/KLSE. WITH THE EXIT OF THE LOW...THE PCPN IS COMING TO AN END.
CLOUDS WILL HANG AROUND...AND SHOULD HOLD MVFR/IFR THROUGH
MUCH OF FRI MORNING. BUFKIT SOUNDINGS INDICATE A MIXING OUT OF THIS
LOW CLOUD LAYER FRIDAY AFTERNOON...WITH RH FIELDS ALSO DEPICTING A
DECREASE IN SATURATION. EXPECT A DIURNAL BUMP UPWARD OF CIGS BY THE
AFTERNOON...AND SCATTERING OUT BEFORE THE EVENING. THAT SAID...THERE
COULD BE FURTHER CU DEVELOPMENT POST THE LOW/S ASSOCIATED CLOUD
SHIELD. IF SO...ANOTHER BKN CIG COULD DEVELOP QUICKLY...BUT WOULD
JUST AS QUICKLY SCATTER OUT WITH THE LOSS OF DAYTIME HEATING.
FOR VSBYS...LATEST SFC OBS ARE MOSTLY P6SM...EVEN IN THOSE AREAS
WITH -RA. WINDS WILL STAY UP TONIGHT/FRIDAY...ENOUGH TO KEEP THE
ATMOSPHERE STIRRED...AND DON/T EXPECT BR/FG DEVELOPMENT AS A RESULT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
405 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 09Z...
* NORTHWEST WINDS BECOME A BIT GUSTY SUNDAY
IZZI
//DISCUSSION...UPDATED 06Z...
DEEP TROUGH WILL CONTINUE TO INFLUENCE THE REGION THIS TAF CYCLE
WITH COLD AIR ALOFT RESULTING IN PERIODIC SCT V BKN VFR
CIGS...PARTICULARLY DURING PEAK HEATING SUNDAY. NORTHWEST WINDS
WILL BECOME GUSTY AGAIN SUNDAY MORNING INTO THE AFTERNOON...THOUGH
LIGHTER THAN ON SATURDAY WITH PEAK GUSTS GENERALLY IN THE 20-25KT
RANGE. SKIES WILL CLEAR OUT AND WINDS GO CALM SUNDAY EVENING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 09Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SLT CHC OF SHRA DURING THE NIGHT.
TUESDAY...VFR. GUSTY SSW WINDS.
WEDNESDAY...SLT CHC OF TSRA.
THURSDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-
LMZ870-LMZ872-LMZ874 UNTIL 9 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
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FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
333 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* NORTHWEST WINDS BECOME A BIT GUSTY SUNDAY
IZZI
//DISCUSSION...UPDATED 06Z...
DEEP TROUGH WILL CONTINUE TO INFLUENCE THE REGION THIS TAF CYCLE
WITH COLD AIR ALOFT RESULTING IN PERIODIC SCT V BKN VFR
CIGS...PARTICULARLY DURING PEAK HEATING SUNDAY. NORTHWEST WINDS
WILL BECOME GUSTY AGAIN SUNDAY MORNING INTO THE AFTERNOON...THOUGH
LIGHTER THAN ON SATURDAY WITH PEAK GUSTS GENERALLY IN THE 20-25KT
RANGE. SKIES WILL CLEAR OUT AND WINDS GO CALM SUNDAY EVENING.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 12Z MONDAY-12Z SATURDAY...UPDATED 00Z...
MONDAY...SLT CHC OF SHRA DURING THE NIGHT.
TUESDAY...VFR. GUSTY SSW WINDS.
WEDNESDAY...SLT CHC OF TSRA.
THURSDAY-FRIDAY...CHC OF TSRA.
MTF
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-
LMZ870-LMZ872-LMZ874 UNTIL 9 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
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AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
145 AM EDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 145 AM EDT SUN MAY 12 2013
LINE OF SCATTERED SHOWERS CROSSING THE CWFA. NOT MUCH PCPN WITH THIS
LINE. AT CURRENT SPEED THE SHRA SHOULD BE EAST OF THE STATE BY 9Z.
THEN THE COLD AIR BEFINS TO MOVE IN. NOT EXPECTING DRAMATIC DROP IN
TEMPS TONIGHT DUE TO THE EXTENSIVE LOW LEVEL CLOUD COVER AND ENUF
WIND TO KEEP SOME OF THE BNDRY LAYER MIXED. SHOULD CLEAR ON SUN SO
SUN NIGHT WILL SEE THE REAL DROP IN OVERNIGHT TEMPS TO RECORD LEVELS
LIKELY. UPDATED GRIDS WITH CURRENT CONDITIONS. WILL UPDATE ZONES WHEN
THE SHRA EXIT THE AREA.
UPDATE ISSUED AT 1115 PM EDT SAT MAY 11 2013
A RECENT UPDATE WAS MADE TO THE GRIDS TO FINE TUNE TIMING OF SHOWER
CHANCES OVER THE NEXT FEW HOURS AND FRESHEN UP HOURLY
TEMPS...DEWPOINTS AND WINDS. THE COLD FRONT IS NOW MOVING THROUGH
CENTRAL KY WITH A BAND OF SHOWERS PRECEDING IT. COLDER AND DRIER AIR
WILL MOVE INTO THE AREA LATER TONIGHT BEHIND THE FRONT.
UPDATE ISSUED AT 810 PM EDT SAT MAY 11 2013
AT PRESENT...SOUTH CENTRAL AND EASTERN KY ARE IN A LULL BETWEEN THE
DEPARTED INITIAL FIRST COLD FRONT AND THE STRONGER SECOND COLD FRONT.
THIS COLD FRONT IS THE LEADING EDGE OF A MUCH COLDER AND DRIER
AIRMASS. ISOLATED TO SCATTERED SHOWERS ARE CURRENTLY ALONG THE
BOUNDARY...BUT OPERATIONAL MODELS INCLUDING THE HRRR AND NAM SHOW SOME
DECREASE IN ACTIVITY ALONG THE BOUNDARY WITH LOSS OF DAYTIME HEATING.
EXTRAPOLATION AND OPERATIONAL MODELS GENERALLY BRING THESE INTO THE
WESTERN COUNTIES AROUND OR A LITTLE BEFORE MIDNIGHT AND THEN DURING
THE OVERNIGHT HOURS ACROSS THE EASTERN HALF OF THE CWA. FEW CHANGES
WERE NEEDED TO THE PREVIOUS TIMING AND THE RECENT UPDATE WAS MAINLY
TO REMOVE AFTERNOON REFERENCES FROM THE ZFP AND ADJUST HOURLY
TEMPS...DEWPOINTS...SKY AND WINDS TO REFLECT RECENT TRENDS. THIS
SCENARIO BRING SOME PARTIAL CLEARING ACROSS THE CWA FOR AN HOUR OR
TWO BEFORE MORE CLOUDS MOVE IN ALONG THE BOUNDARY. ALTHOUGH THE
CURRENT BAND OF CLOUDS IS RATHER NARROW POST FRONTAL FLOW THAT IS OUT
OF THE NORTHWEST SHOULD TEND TO LINGER CLOUDS A LITTLE LONGER THAN
BAND OF CLOUDS TO THE WEST WOULD INDICATE AND THIS WAS ALREADY
HANDLED WELL IN THE PREVIOUS FORECAST.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 354 PM EDT SAT MAY 11 2013
ISOLATED TO SCATTERED SHOWERS WILL WIND DOWN OVER THE NEXT COUPLE OF
HOURS AS THE SURFACE COLD FRONT HAS SHIFTED OFF TO THE SOUTHEAST OF
THE AREA. THE NEXT COLD FRONT IS CURRENTLY ALIGNED FROM NORTHEAST
INDIANA DOWN THROUGH SOUTHEAST MISSOURI. MOST OF THE SHOWER ACTIVITY
ASSOCIATED WITH THIS BOUNDARY IS LOCATED NORTH OF THE OHIO RIVER.
THE MODELS ARE IN GOOD AGREEMENT WITH BRINGING THIS SECONDARY
BOUNDARY THROUGH THE AREA LATER THIS EVENING...WITH ISOLATED TO
SCATTERED SHOWERS THREATENING ONCE AGAIN...ALTHOUGH MOST GUIDANCE
INDICATES A DOWNTREND IN CONVECTION AS THE BOUNDARY MOVES ACROSS
EASTERN KENTUCKY. LOWS TONIGHT WILL BOTTOM IN THE LOW TO MID 40S FOR
MOST LOCATIONS.
AFTER AN UNSEASONABLY COOL MOTHER/S DAY WITH HIGHS TOPPING OUT AT
AROUND 60 DEGREES...A CHILLY SUNDAY NIGHT WILL BE IN STORE. THE MODEL
GUIDANCE CONTINUES TO SHOW NEAR RECORD LOWS OF LOWER TO MIDDLE 30S.
HAVE THEREFORE HIGHLIGHTED THE COOLER TEMPERATURES AND THE
POSSIBILITY OF FROST IN AN SPS...ALTHOUGH WITH THE GREEN PRETTY MUCH
IN FULL SWING AND SATURATED GROUND FROM RECENT RAINFALL...THE FOG MAY
WIND UP BEING MORE PREVALENT THAN THE FROST.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 310 PM EDT SAT MAY 11 2013
THE MODELS START OUT THE EXTENDED IN EXCELLENT AGREEMENT ALOFT AS
THEY ALL HAVE A DEEP TROUGH EXTENDING FROM THE GREAT LAKES...
THROUGH THE OHIO VALLEY...AND TO THE DEEP SOUTH. THIS TROUGH WILL
QUICKLY PULL EAST DURING THE DAY MONDAY ALLOWING HEIGHTS TO RISE
OVER EAST KENTUCKY INTO MONDAY NIGHT. MODERATE RIDGING WILL THEN
BUILD INTO THE STATE FROM THE WEST AND LATER NORTH FROM THE CENTRAL
GULF COAST. BY WEDNESDAY MORNING...THOUGH...SOME DISTINCT
DIFFERENCES START TO CROP UP AMONGST THE MODELS IN BOTH THE NORTHERN
AND SOUTHERN STREAMS. A WELL DEFINED MID LEVEL LOW RUNNING EAST
ALONG THE CANADIAN BORDER...IN THE GFS...IS REPRESENTED AS A
WEAKER...MORE PROGRESSIVE...OPEN WAVE IN THE 00Z ECMWF. THE LATEST
GEM APPEARS TO BE SIDING WITH THE GFS WITH THIS FEATURE. THE NET
RESULT FOR EAST KENTUCKY WILL BE SIMILAR REGARDLESS OF WHICH SOLUTION
PANS OUT AS THERE REMAINS GOOD AGREEMENT THAT RIDGING WILL BE IN
PLACE OVER OUR AREA THROUGH MIDWEEK. WHILE THE NORTHERN DETAILS WORK
THEMSELVES OUT...TO THE SOUTH A WEAKENING IMPULSE WILL MOVE THROUGH
THE SOUTHERN PLAINS LIKELY SERVING TO SUPPRESS THE LOCAL RIDGING AS
IT MOVES CLOSER TO THE CWA ON THURSDAY. IN FACT...BY 00Z FRIDAY THE
GFS IS SHOWING A FLAT TO SLIGHTLY TROUGHING PATTERN OVER EAST
KENTUCKY WHILE THE ECMWF STILL HAS THE BACK EDGE OF RIDGING HOLDING
ON THROUGH THE APPALACHIANS. DESPITE THE PATTERN DIFFERENCES...THE
HEIGHTS ARE RATHER SIMILAR OVER THE AREA INTO FRIDAY...ALONG WITH A
HEALTHY MIX OF ENERGY...KEEPING THINGS UNSETTLED. FOR SATURDAY...
WEAK RIDGING WILL REMAIN IN PLACE THROUGH THE AREA AS ANY IMPRESSIVE
WAVES STAY WELL NORTH OF THE AREA...MORE BEFITTING OF THIS TIME OF
YEAR. GIVEN THE SIMILARITY AND GENERAL CONSENSUS EXHIBITED BY THE
MODELS OVER EAST KENTUCKY THROUGH THE PERIOD...WILL FOLLOW A BLENDED
SOLUTION WITH LITTLE APPREHENSION...AND SOME CONFIDENCE THAT A MORE
NORMAL LATE SPRING WX PATTERN IS NEARLY UPON US.
AS FOR SENSIBLE WEATHER...MONDAY WILL START OUT CHILLY AND FROSTY
BUT MODERATE QUICKLY A HIGH PRESSURE MOVES INTO THE OHIO VALLEY. THE
WARMING WILL CONTINUE INTO TUESDAY AS A WARM FRONT PASSES TO THE
NORTH OF THE AREA. THIS WILL SET THE STAGE FOR A RARITY OF THIS
SPRING...A DAY OF ABOVE NORMAL TEMPERATURES...ON WEDNESDAY. ABOUT
THIS TIME A DEVELOPING FRONT SETS UP NORTH OF THE OHIO RIVER AND
INCREASING MOISTURE WILL BRING WITH IT BETTER CHANCES FOR CONVECTION
ON THURSDAY. THIS NEARBY FRONT...A MOIST BOUNDARY LAYER...AND WARM
TEMPERATURES WILL LIKELY KEEP...AT LEAST DIURNALLY DRIVEN...SHOWERS
AND THUNDERSTORMS AROUND THROUGH THE END OF THE WEEK AND INTO
SATURDAY. THE PRICE OF A MORE NORMAL SPRING PATTERN...AND A LACK OF
STRONG HIGH PRESSURE...DURING THE LATTER PART OF THE FORECAST WILL
BE A PATTERN MORE SIMILAR TO EARLY SUMMER MAKING AFTERNOON AND
EVENING CONVECTION A GOOD BET.
THE CR GRID LOAD CAME IN PRETTY GOOD...DID MAKE HOURLY ADJUSTMENTS
TO THE POPS AND SKY COVER TO BETTER HONE IN ON THE TIMES OF PEAK
CONVECTION FROM THURSDAY ON. ALSO...MADE SOME TERRAIN BASED
ADJUSTMENTS TO LOW TEMPERATURES EACH NIGHT FROM MONDAY THROUGH
WEDNESDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 815 PM EDT SAT MAY 11 2013
DURING THE FIRST 3 TO 7 HOURS OF THE PERIOD...THE REGION WILL BE A
RELATIVE LULL IN CLOUDS BETWEEN THE DEPARTED COLD FRONT AND ANOTHER
APPROACHING COLD FRONT AND ASSOCIATED BAND OF CLOUDS AND SCATTERED
SHOWERS. DURING THE LULL AN IMPROVEMENT TO VFR SHOULD OCCUR IN ALL
BUT THE HIGHEST TERRAIN THE SOUTHEAST WHERE SKIES SHOULD IMPROVE TO
MVFR FROM IFR. A DROP DOWN TO MVFR OR PERHAPS LOWER IS ANTICIPATED
ALONG AND FOR ABOUT 3 HOURS BEHIND THE BOUNDARY. DRY AIR ADVECTION IN
LOWER LEVELS SHOULD LEAD TO IMPROVEMENTS BACK TO VFR AFTER THAT PERIOD.
WINDS WILL BE A BIT GUSTY FROM NW OR NNW...ESPECIALLY 15Z TO 22Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...DUSTY
SHORT TERM...GEOGERIAN
LONG TERM...GREIF
AVIATION...JP
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1255 AM EDT SUN MAY 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH LATER TONIGHT AND CROSS THE REGION ON
SUNDAY WITH ADDITIONAL AFTERNOON SHOWERS. COLDER AND DRIER AIR WILL
FOLLOW FOR EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
1255 AM UPDATE...MAIN CHANGES WITH THIS UPDATE WERE TO POPS TO
MATCH THEM TO CURRENT RADAR TRENDS. THE FRONT IS BISECTING THE
FORECAST AREA RIGHT NOW AND SHOWERS HAVE PRETTY MUCH HAVE COME TO
AN END ACROSS NORTHWESTERN MAINE. THE BEST CHANCES FOR
PRECIPITATION FOR THE REMAINDER OF TONIGHT/THIS MORNING WILL BE
ACROSS FAR DOWNEAST AREAS, AS RADAR SHOWS AN OFFSHORE BAND OF
WIDESPREAD SHOWERS WILL CONTINUE BRUSH COASTAL AREAS. ELSEWHERE,
SHOWERS WILL BE SCATTERED IN NATURE. OTHER THAN POPS, THE GOING
FORECAST WAS ON TRACK, SO NO OTHER CHANGES WERE NEEDED.
PREVIOUS DISCUSSION: MAIN CHALLENGES WILL BE TIMING OF RAIN
TONIGHT INTO SUNDAY AND TEMPERATURES.
FIRST AREA OF RAIN MOVING TO THE E INTO NEW BRUNSWICK WHILE SEND
AREA OF RAIN AND POSSIBLE TSTMS MOVING INTO SWRN AREAS ATTM PER
THE LATEST RADAR. THIS SECOND AREA OF RAIN WILL OVERSPREAD THE CWA
LATER THIS AFTERNOON INTO EARLY TONIGHT. 12Z UA INDICATED A STRONG
40KT JETLET AT 700MBS ACROSS ONTARIO AND WRN NYS. THIS AREA OF
FORCING WAS PICKED UP BY THE GFS AND CANADIAN GEM. THEREFORE, A
BLEND OF THESE 2 MODELS WERE USED INTO EARLY TONIGHT AS THEY SHOW
A SIGNIFICANT AREA OF RAIN MOVING ACROSS THE REGION. ATMOSPHERE
LOOKS LIKE IT STABILIZES AFTER 22Z AND THEREFORE CUT BACK ON THE
MENTION OF TSTMS FOR OUR CWA. THE LATEST RAP FROM THE SPC MESO-
ANALYSIS PAGE INDICATED SOME POSSIBLE TSTMS EDGING INTO GYX/S WRN
ZONES THIS AFTERNOON AND THEN WEAKENING BY 22Z OR SO. A BLEND OF
THE NERFC/GFS AND SREF WAS USED FOR THE QPF WHICH SHOWED AN
ADDITIONAL 0.15-0.30 THROUGH 06Z AND THEN RAIN END AS THE BEST
FORCING EXITS INTO NEW BRUNSWICK. ADDED FOG FOR ALL THE CWA
OVERNIGHT W/THE MOST DENSE FOG FROM MLT REGION ON SOUTH.
TEMPERATURES WILL BE HELD UP TONIGHT AND FOLLOWED A BLEND OF THE
NAM12 AND REGIONAL GEM FOR TONIGHT`S LOWS SHOWING UPPER 40S OUT
WEST TO LOW TO MID 50S EASTERN AND CENTRAL AREAS.
FOR SUNDAY, DRY W/SOME FOG TO START AND THEN ANOTHER BATCH OF
SHOWERS EXPECTED BY MIDDAY DUE TO THE COLD FRONT APCHG FROM THE W.
STAYED W/A GEM/GFS BLEND FOR TIMING OF THE SHOWERS USING THE MID
LEVEL FORCING FOR THE QPF WHICH SHOWED ANOTHER .10-.20, MAINLY
NORTHERN AND CENTRAL AREAS. HELD BACK THE TEMPERATURES FROM PREVIOUS
THINKING AND LEANED W/LOWER 60S NORTH AND MID 60S CENTRAL AND
DOWNEAST AS CAA LOOKS TO TAKE HOLD IN THE AFTERNOON. TSTM
POTENTIAL LOOKS TO BE LESS LIKELY ESPECIALLY ACROSS THE DOWNEAST
AND COAST DUE TO THE ONSHORE FLOW. BEST CHANCES IF ANY WILL BE
ACROSS THE NORTHERN AND WESTERN AREAS DUE TO SOME ELEVATED
INSTABILITY. ATTM, KEPT ISOLATED THUNDER IN THERE FOR CONTINUITY.
MIDNIGHT CREW CAN ASSESS THIS FURTHER TONIGHT.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
THE FIRST PART OF THE PERIOD WILL BEGIN WITH SHOWERS ACROSS THE
NORTHERN AND CENTRAL PARTS OF THE REGION SUNDAY NIGHT. THESE
SHOWERS ARE DUE TO A BOUNDARY THAT WILL MOVE FROM WEST TO EAST.
THE BEST LIFT LOOKS TO BE ACROSS THE NORTH. ONCE THIS FRONTAL
BOUNDARY PUSHES THROUGH THE REGION TEMPERATURES WILL COOL OFF FOR
MONDAY WITH HIGHS IN THE 50S NORTH AND THE UPPER 50S TO LOWER 60S
SOUTH. AS THE UPPER LEVEL TROUGH MOVES EAST THE 12Z GFS IS TRYING
TO CLOSE THE TROUGH TO THE NORTH WHILE THE 12Z NAM/00Z ECMWF
CONTINUE TO DEVELOP THE CLOSED LOW AROUND THE BASE OF THE TROUGH.
RIGHT NOW WILL LEAN WITH THE SURFACE LOW DEVELOPS TRACKING MAINLY
EAST OF THE AREA LATE TUESDAY INTO TUESDAY NIGHT. MAIN AFFECT TO
THE FORECAST FOR THIS PERIOD WILL BE THE INCREASE IN CLOUDS
COVERAGE WITH HIGHEST COVERAGE SEEN ACROSS THE EASTERN AND
SOUTHEASTERN PARTS OF THE REGION.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
BOTH MEDIUM RANGE MODELS ARE IN GENERAL AGREEMENT IN THE TUESDAY
NIGHT THROUGH THROUGH SUNDAY TIME FRAME. THE FORECAST FOR
WEDNESDAY CONTINUES TO BE DRY. MOISTURE INCREASES WEDNESDAY
NIGHT...AHEAD OF THE NEXT SYSTEM EXPECTED TO MOVE THROUGH THE
AREA...BRINGING A CHANCE OF RAIN MAINLY ON THURSDAY. AT THIS POINT
IT APPEARS WE MAY HAVE A BREAK BETWEEN SYSTEMS ON FRIDAY HOWEVER
LATE FRIDAY INTO SATURDAY SHOULD SEE RAIN CHANCES INCREASE ACROSS
THE REGION ONCE AGAIN. SEASONAL TEMPERATURES ARE EXPECTED THROUGH
THE PERIOD WITH SOME DAYS A LITTLE ABOVE NORMAL AND OTHERS WITH
READINGS A LITTLE BELOW.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
NEAR TERM: IFR INTO SUNDAY MORNING AND THEN CONDITIONS GO TO MVFR
ESPECIALLY NORTHERN TERMINALS.
SHORT TERM: MOST TAF SITES WILL STAY VFR THROUGH THE PERIOD
EXCEPT FOR SUNDAY NIGHT WITH HEAVIER SHOWERS THERE COULD BE
PERIODS OF MVFR OR IFR.
&&
.MARINE...
NEAR TERM: DECIDED TO TRANSITION THE SCA TO HAZARDOUS SEAS INTO
SUNDAY. WAVES ARE CLIMBING TO 6 ATTM W/A SWELL GENERATED. WILL
CARRY THE MENTION OF THE SWELL INTO SUNDAY. WINDS ARE BELOW SCA
AND EXPECTING THEM TO STAY BELOW INTO SUNDAY. FOLLOWED THE
NAM12/GFS40 BLEND FOR THE WINDS AND FOLLOWED CLOSELY W/THE
MIDNIGHT CREW`S WAVE HEIGHTS OF 4-7 FT.
SHORT TERM: SCA CONDITIONS SUBSIDE BY THE SHORT TERM PERIOD.
KEPT CONSISTENCY WITH LAST NIGHTS SHIFT FOR WAVE AND WIND GRIDS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 4 PM EDT THIS
AFTERNOON FOR ANZ050>052.
&&
$$
NEAR TERM...HASTINGS/HEWITT
SHORT TERM...JORDAN
LONG TERM...RUNYAN
AVIATION...HASTINGS/HEWITT/JORDAN
MARINE...HASTINGS/HEWITT/JORDAN
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
554 AM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 549 AM EDT SUN MAY 12 2013
UPPER PATTERN FEATURING WESTERN CONUS RIDGING AND EASTERN CONUS
TROUGHING BECOMES MORE ZONAL THROUGH THE WEEK...RESULTING IN
WARMING TREND FOR UPPER GREAT LAKES. AS THE UPPER PATTERN BECOMES
MORE ZONAL EXPECT SFC LOW AND FRONTAL BOUNDARIES TO MOVE FROM
CENTRAL CANADA ACROSS THE GREAT LAKES TUESDAY THROUGH THURSDAY. BEST
CHANCE OF RAIN IN THIS PATTERN SHOULD BE LATER TUESDAY THROUGH
TUESDAY NIGHT AS WARM FRONT SLIDES ACROSS UPPER GREAT LAKES. EXTENT
OF COOLING BEHIND COLD FRONT WEDNESDAY INTO THURSDAY UNCERTAIN. EVEN
THE MODELS THAT ARE SHOWING THE MOST EMPHATIC COOLING /GFS AND NAM/
SHOW NOTHING TO THE EXTENT OF CURRENT COOLDOWN THAT IS CURRENTLY
OCCURRING. SO...BEYOND THIS TASTE OF WINTER AFFECTING THE REGION
THIS MORNING...EXPECT EXTENDED TO HOLD ONLY LIQUID PRECIPITATION.
HIGH PRESSURE BEGINS THE EXTENDED PERIOD OVER WESTERN GREAT LAKES.
RIDGE AXIS HEADS ACROSS REST OF GREAT LAKES BY MONDAY NIGHT ALLOWING
WARM AIR ADVECTION/RETURN FLOW TO DEVELOP. THROUGH DAY 2 LEANED ON
THE NAM/GFS SOUNDINGS TO TRY TO GAGE PRECIP CHANCES. MOISTURE
ADVECTION FOCUSED MAINLY ALOFT H85-H7 MONDAY NIGHT. SOME LGT SHOWERS
SEEM LIKELY IN MAX ADVECTION AREA MOVING WEST TO EAST ACROSS CWA.
ONCE MID-LEVEL MOISTURE/LIFT IS STRIPPED AWAY...SHALLOW MOISTURE
MAINLY BLO H9 IS ALL THAT IS LEFT ON TUESDAY. HINTS FROM MODELS THAT
MOISTURE MAY MIX OUT BY AFTN. LOWERED POPS BASED ON LIMITED MOISTURE
INTO TUESDAY AFTN. NEXT SURGE OF MOISTURE/TEMPERATURE ADVECTION AND
ELEVATED INSTABILITY COULD BRING SHOWERS/TSRA OVER GENERALLY WESTERN
CWA LATE TUESDAY AFTN. SE WINDS AHEAD OF WARM FRONT WITH MORE
INFLUENCE OFF LK MICHIGAN FOR MUCH OF CWA SHOULD KEEP TEMPS FROM
GETTING TOO WARM EVEN WITH ONLY SCT CLOUDS BY AFTN. WARMEST READINGS
INTO THE 70S INLAND WEST AND SOUTHWEST CWA WITH LESS LAKE MODIFIED
COOLER AIR. UPR 50S TO UPR 60S ELSEWHERE.
WARM FRONT PASSAGE/MAXIMUM LOW-LEVEL MOISTURE AND TEMP ADVECTION
STILL ON TRACK FOR TUESDAY NIGHT. HAS LOOKED THIS WAY FOR A WHILE
NOW. STILL THINKING THIS IS THE BEST CHANCE FOR SHOWERS AND TSRA
ACROSS CWA...BUT STILL MAY NOT BE WIDESPREAD EVENT FOR ALL CWA. SOME
DIFFERENCE HOW FAR SOUTH SHORTWAVE TROUGH/MID-LEVEL HEIGHT FALLS DIP
INTO UPR LAKES AND THIS IMPACTS SOUTHERN EXTENT OF PRIMARY UPPER
LEVEL JET AND ASSOCIATED DIVERGENCE TO ENHANCE PRECIP. PLACED LIKELY
POPS OVER NORTH AND EAST AND KEPT POPS SCATTERED FARTHER SOUTH. GIVEN
H85 DWPNTS OVER +12C AND 1-6KM MUCAPES OVER 1000J/KG AND SINCE AXIS
OF 925-850MB WIND MAX IS OVERHEAD...SHRA AND TSRA CANNOT BE COUNTED
OUT ANYWHERE THOUGH. STRONGST WINDS ALOFT ARE MORE OVER LAKE SUPERIOR
AND NORTH INTO ONTARIO SO THINK THIS IS WHERE BETTER CHANCE OF
STRONGER STORMS WOULD BE LOCATED. SEEMS THAT LIGHTNING AND HEAVY
DOWNPOURS WILL BE THE PRIMARY HAZARDS. THOUGH WBZERO HEIGHTS
11-12KFT IS ON THE HIGHER SIDE TO SEE LARGE HAIL...IT IS POSSIBLE
GIVEN STRONGER SHEAR AND H7-H5 LAPSE RATES OVER 7C/KM.
GOOD AGREEMENT THAT AREA OF ENHANCED PRECIP SWIFTLY CROSSES THE AREA
LATER TUESDAY NIGHT WITH COLD FRONTAL PASSAGE NOT TOO FAR BEHIND ON
WEDNESDAY MORNING. SUBSTANTIAL CLEARING IN THE OFFING ON WEDNESDAY
IN WAKE OF THE FRONT. 00Z ECMWF TRENDED SLIGHTLY TOWARD COLDER GFS
IDEA FOR H85 TEMPS IN WAKE OF COLD FRONT...BUT EVEN SO...EXPECT
SUNSHINE AND DEEP MIXING TO OFFSET THIS AND LEAD TO MAX TEMPS INTO
THE 70S SOUTHWEST AND SOUTH CENTRAL. READINGS IN THE 60S CLOSER TO
LK SUPERIOR. WINDS MAY END UP STRONGER THAN WHAT CONSENSUS SHOWED
BUT LEFT THEM ALONE FOR NOW. DID GO WITH LOWER BIAS CORRECTED MOS
DWPNTS IN THE AFTN GIVEN THE DEEP MIXING.
THURSDAY AND FRIDAY....A BIT UNSETTLED POTENTIALLY. PRIMARY SFC
FRONTAL BOUNDARY WILL REMAIN SOUTH OF UPR MICHIGAN. YET SINCE THE
AREA IS ON SOUTHERN EDGE OF TROUGH OVR CANADA...THE JET STREAM IS
TOO CLOSE BY TO NOT HAVE AT LEAST SLIGHT CHANCE POPS. MODELS HAVE
SHOWN SOME QPF FROM TIME TO TIME...ESPECIALLY LATER FRIDAY AND
FRIDAY NIGHT AS SECONDARY SFC TROUGH DIPS SOUTH ACROSS THE UPPER
GREAT LAKES.
BY NEXT WEEKEND THE MAIN ISSUE WILL BE INFLUENCE OF DEVELOPING LOW
PRESSURE OVER PLAINS. 12Z ECMWF FARTHER TO THE EAST...WHILE GFS AND
WPC HAND DRAWN PROGS KEEP LOW SHUNTED MORE OVER THE PLAINS AND SFC
RIDGE OVER THE UPR LAKES. CONSENSUS OF MODELS WHICH HAS DOUBLE
WEIGHTING OF THE TYPICALLY BETTER PERFORMING ECMWF SHOWS INCREASING
CHANCES OF SHOWERS BY LATER IN THE WEEKEND. TEMPS TO END THE
EXTENDED WILL BE AROUND NORMAL...THOUGH MAY REMAIN SLIGHTLY BELOW
NORMAL ALONG LK SUPERIOR DUE TO PREVAILING NORTHERLY SFC WINDS.
EVEN IF IT DOES END UP BELOW NORMAL...NO SNOW IS IN THE
FORECAST...WHICH IS CERTAINLY WELCOME NEWS FOR THOSE WEARY OF THE
WINTER THAT HAS BEEN RELUCTANT TO END.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 549 AM EDT SUN MAY 12 2013
SOME LAKE ENHANCEMENT SNOW SHOWERS WILL CONTINUE AT CMX AND SAW
OVERNIGHT WITH MVFR CONDITIONS AT CMX AND IFR CONDITIONS AT SAW IN
THE HEAVIER SNOW SHOWERS. DRY AIR COMES IN LATE SUN MORNING AND IWD
AND CMX WILL GO BACK TO VFR CONDITIONS. IT WILL TAKE A BIT LONGER TO
GET THE DRY AIR INTO SAW AND THE MVFR CIGS WILL SCATTER OUT BY SUN
AFTERNOON. WILL BE GUSTY THROUGH SUN AFTERNOON AT CMX AND SAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ248.
LAKE MICHIGAN...
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LMZ250.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...07
MARINE...JLA
AREA FORECAST DISCUSSION
NWS HASTINGS NE
352 AM CDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1231 AM CDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF VALID PERIOD. THE WIND
WILL REMAIN OUT OF THE SOUTHEAST. THERE IS A SLIGHT CHANCE OF A
FEW SPRINKLES AROUND DAWN...BUT NOTHING SIGNIFICANT ENOUGH TO
WARRANT BEING PLACED IN THE TAF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...FROST ADVISORY UNTIL 9 AM CDT THIS MORNING FOR NEZ039>041-048-
049-064.
KS...NONE.
&&
$$
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
148 AM EDT SUN MAY 12 2013
.SYNOPSIS...
A SLOW-MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE EASTWARD
FROM THE GREAT LAKES FOR SUNDAY AND MONDAY...BRINGING THE CHANCE
FOR A FEW ISOLATED RAIN SHOWERS. THE AIR MASS WILL BE COLD ENOUGH
TO SUPPORT A FEW SNOW SHOWERS IN THE ADIRONDACKS DURING SUNDAY
NIGHT. CLEARING SKIES ARE EXPECTED MONDAY NIGHT AS A SURFACE RIDGE
CRESTS OVER THE NORTH COUNTRY. ASSOCIATED LIGHT WINDS WILL BRING
THE POSSIBILITY FOR PATCHY FROST DURING MONDAY NIGHT AS
TEMPERATURES FALL BACK INTO THE LOW TO MID 30S. A GRADUAL
MODERATING TREND IS EXPECTED BEGINNING TUESDAY AND THROUGH THE
MIDDLE OF NEXT WEEK. AN APPROACHING WARM FRONT MAY BRING
ADDITIONAL SHOWERS LATE WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 113 AM EDT SUNDAY...MOSTLY CLOUDY SKIES CONTINUE TONIGHT
WITH THE NORTH COUNTRY UNDER WEAK SFC RIDGING IN THE WAKE OF THE
COLD FRONT THAT PASSED THROUGH EARLIER. THE MORE SIGNIFICANT COLD
FRONT IS NOW ENTERING FAR WESTERN NEW YORK STATE AND IS MOVING
QUICKLY EASTWARD AIDED BY A 70-KT MID-LEVEL JET MAX. THE FRONTAL
POSITION IS PRETTY EVIDENT IN IR SATELLITE IMAGERY BY A LINE OF
COOLER CLOUD TOP TEMPERATURES. GIVEN THE FASTER FRONTAL APPROACH
HAVE SPED UP THE TIMING OF THE FRONT BY A COUPLE HOURS BRINGING IT
INTO THE SAINT LAWRENCE VALLEY AROUND SUNRISE. INTRODUCED A SLIGHT
CHANCE OF SHOWERS BASED ON RADAR AND SFC OBSERVATIONAL TRENDS AND
RECENT RAP MODEL OUTPUT. WINDS ALSO WILL BEGIN TO PICK UP FROM THE
SOUTHWEST IN THE SAINT LAWRENCE VALLEY. THE REST OF THE NORTH
COUNTRY WILL BE CLOUDY BUT DRY THROUGH THE REST OF THE OVERNIGHT.
NO CHANGES TO LOW TEMPERATURES...GENERALLY IN THE 40S TO AROUND 50
DEGREES.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 337 PM EDT SATURDAY...UPPER-LEVEL LOW ACROSS THE GREAT
LAKES REGION TONIGHT AMPLIFIES AS IT SHIFTS EWD WITH LOW CENTER
ACROSS SERN ONTARIO AT 18Z SUNDAY...AND THEN LIFTS NEWD ACROSS
SRN QUEBEC DURING THE DAY MONDAY. MAIN IMPACT WILL BE COOLER
TEMPERATURES ACROSS THE NORTH COUNTRY WITH THIS FEATURE.
SECONDARY FRONTAL BNDRY CROSSES THE REGION FROM W-E DURING SUNDAY
AFTN AND MAY BRING ISOLD/SCATTERED LIGHT RAIN SHOWERS. MOST OF
THIS ACTIVITY WILL BE HIT OR MISS AND KEPT POPS GENERALLY ON THE
LOW SIDE (20-30 PERCENT). STEEP LAPSE RATES AND MODERATE GRADIENT
FLOW COULD YIELD SOME WIND GUSTS 35-40 MPH ACROSS THE NRN
ADIRONDACKS AND ST. LAWRENCE VALLEY. SHOULD REMAIN BELOW WIND
ADVISORY CRITERIA...BUT WILL BE BREEZY FOR MUCH OF SUNDAY
AFTN...ESPECIALLY ACROSS NRN NY. HIGHS SUNDAY AFTN GENERALLY IN
THE LOW-MID 50S ACROSS NRN NY...BUT INTO THE LOWER 60S FOR THE
VALLEYS OF VT...AND CLOSER TO 64-65F IN THE CT RIVER VALLEY.
ADDITIONAL LOW-LEVEL COLD ADVECTION SUNDAY NIGHT BRINGS 850MB
TEMPS OF -7 TO -8C ACROSS LAKE ONTARIO WITH SUFFICIENT LAKE
INDUCED INSTABILITY TO GENERATE SOME LAKE EFFECT RAIN/SNOW
SHOWERS DURING SUNDAY NIGHT. HAVE INDICATED A REGION OF 40-60
POPS ACROSS SRN ST. LAWRENCE INTO SRN FRANKLIN COUNTY NY DURING
SUNDAY NIGHT TO ACCOUNT FOR THIS LAKE EFFECT ACTIVITY. COULD SEE
A LIGHT COATING OF SNOW IN THE ADIRONDACKS 06-12Z MONDAY WITH
LOWS AROUND 30-32F. ELSEWHERE...NOT MUCH FORCING FOR ASCENT...SO
REMAINDER OF THE FORECAST AREA SHOULD BE DRY WITH LOWS IN THE MID
30S. ENOUGH GRADIENT WIND IN THE CHAMPLAIN VALLEY SHOULD PRECLUDE
ANY FROST POTENTIAL FOR SUNDAY NIGHT WHERE THE GROWING SEASON IS
CONSIDERED ACTIVE.
ON MONDAY...MID-LEVEL TROUGH AXIS SHIFTS EWD ACROSS THE REGION
WITH 850MB TEMPS AROUND -4C. SHOULD BE THE COOLEST DAY OF THE
STRETCH WITH VALLEY HIGH TEMPERATURES MONDAY ONLY IN THE LOW-MID
50S. STEEP LAPSE RATES MAY YIELD A FEW SHOWERS WITH DAYTIME
HEATING...ESPECIALLY OVER THE NRN MTNS. OTHERWISE...ANTICIPATE A
MIX OF SUN AND CLOUDS ACROSS THE REGION.
SFC RIDGE AXIS CRESTS OVERHEAD DURING MONDAY NIGHT WITH
ASSOCIATED LIGHT WINDS AND CLEARING SKIES. GROWING SEASON IS
UNDERWAY IN THE CHAMPLAIN VALLEY...AND ANTICIPATE PATCHY FROST
FORMATION WITH LOWS 33-35F THAT MAY REQUIRE COVERING OF TENDER
VEGETATION. HAVE INCLUDED MENTION IN THE HAZARDOUS WEATHER
OUTLOOK AND IN THE FORECAST AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 430 PM EDT SATURDAY...PROGRESSIVE UPPER LEVEL FLOW SETS UP
ACROSS THE NORTH COUNTRY FOR THE TUESDAY THROUGH SATURDAY TIME
FRAME. THERE WILL BE SEVERAL CHANCES FOR SHOWERS AS BLOCKING
PATTERN SETS UP TO OUR EAST AND WILL CAUSE SEVERAL SHORTWAVES TO
CROSS OUR FORECAST AREA. DEVELOPING OMEGA BLOCK OVER THE NORTH
CENTRAL ATLANTIC OCEAN AND HEAT RIDGE ACROSS SOUTHEASTERN UNITED
STATES KEEPS NORTHEAST US RIGHT ALONG THE PERIPHERY OF A BUILDING
UPPER RIDGE. IN THE THU-SAT TIME FRAME A LOW PRESSURE SYSTEM WILL
PASS NORTH OF THE REGION AND BRING CHANCE FOR SHOWERS TO THE AREA.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...COLD FRONT APPROACHING FROM THE WEST THIS
MORNING WITH SOME MVFR CIGS AND LIGHT RA OR DZ SPOTTY ALONG THE
FRONT. MVFR CONDITIONS MAINLY TO AFFECT KMSS AND KSLK WITH THE
FRONT...WITH KMPV AND KRUT EXPERIENCING SOME MVFR CIGS ASSOCIATED
WITH MOISTURE FROM YESTERDAYS FRONTAL SYSTEM. BEHIND THE FRONT
WILL SEE FEW BREAKS...WITH VFR CIGS AT ALL TAF SITES FOR AT LEAST
A FEW HRS IN THE LATE MORNING. OTHERWISE...SW FLOW WILL KEEP
MOISTURE STREAMING OVER KSLK...WITH MVFR CIGS EXPECTED ONCE AGAIN
IN THE AFTN...WHILE REST OF THE TAF SITES EXPERIENCE VFR
CONDITIONS.
OF CONCERN WILL BE WINDS AND WIND GUSTS. AROUND AND BEHIND THE
FRONT...SW-WSW FLOW WILL DEVELOP WITH WIND SPEEDS OF 8-16 KTS AND
GUSTS OF 20-35 KTS DEVELOPING THIS MORNING...INCREASING IN THE
AFTN AND EARLY EVENING HRS. GUSTS WILL LIKELY SUBSIDE A BIT AFTER
SUNSET...BUT BREEZY CONDITIONS WILL CONTINUE INTO THE OVERNIGHT.
OUTLOOK 06Z MONDAY THROUGH THURSDAY...
06Z MONDAY THROUGH 00Z TUESDAY...MAINLY VFR THOUGH SPOTTY
INSTABILITY-DRIVEN LIGHT SHOWERS COULD PRODUCE PERIODS OF MVFR.
00Z TUESDAY THROUGH 12Z WEDNESDAY...VFR UNDER HIGH PRESSURE.
12Z WEDNESDAY THROUGH THURSDAY...VFR WITH MVFR PSBL WITHIN SCT
SHOWERS.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...EVENSON/LOCONTO
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...KGM
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
113 AM EDT SUN MAY 12 2013
.SYNOPSIS...
A SLOW-MOVING UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE EASTWARD
FROM THE GREAT LAKES FOR SUNDAY AND MONDAY...BRINGING THE CHANCE
FOR A FEW ISOLATED RAIN SHOWERS. THE AIR MASS WILL BE COLD ENOUGH
TO SUPPORT A FEW SNOW SHOWERS IN THE ADIRONDACKS DURING SUNDAY
NIGHT. CLEARING SKIES ARE EXPECTED MONDAY NIGHT AS A SURFACE RIDGE
CRESTS OVER THE NORTH COUNTRY. ASSOCIATED LIGHT WINDS WILL BRING
THE POSSIBILITY FOR PATCHY FROST DURING MONDAY NIGHT AS
TEMPERATURES FALL BACK INTO THE LOW TO MID 30S. A GRADUAL
MODERATING TREND IS EXPECTED BEGINNING TUESDAY AND THROUGH THE
MIDDLE OF NEXT WEEK. AN APPROACHING WARM FRONT MAY BRING
ADDITIONAL SHOWERS LATE WEDNESDAY INTO WEDNESDAY NIGHT.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 113 AM EDT SUNDAY...MOSTLY CLOUDY SKIES CONTINUE TONIGHT
WITH THE NORTH COUNTRY UNDER WEAK SFC RIDGING IN THE WAKE OF THE
COLD FRONT THAT PASSED THROUGH EARLIER. THE MORE SIGNIFICANT COLD
FRONT IS NOW ENTERING FAR WESTERN NEW YORK STATE AND IS MOVING
QUICKLY EASTWARD AIDED BY A 70-KT MID-LEVEL JET MAX. THE FRONTAL
POSITION IS PRETTY EVIDENT IN IR SATELLITE IMAGERY BY A LINE OF
COOLER CLOUD TOP TEMPERATURES. GIVEN THE FASTER FRONTAL APPROACH
HAVE SPED UP THE TIMING OF THE FRONT BY A COUPLE HOURS BRINGING IT
INTO THE SAINT LAWRENCE VALLEY AROUND SUNRISE. INTRODUCED A SLIGHT
CHANCE OF SHOWERS BASED ON RADAR AND SFC OBSERVATIONAL TRENDS AND
RECENT RAP MODEL OUTPUT. WINDS ALSO WILL BEGIN TO PICK UP FROM THE
SOUTHWEST IN THE SAINT LAWRENCE VALLEY. THE REST OF THE NORTH
COUNTRY WILL BE CLOUDY BUT DRY THROUGH THE REST OF THE OVERNIGHT.
NO CHANGES TO LOW TEMPERATURES...GENERALLY IN THE 40S TO AROUND 50
DEGREES.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 337 PM EDT SATURDAY...UPPER-LEVEL LOW ACROSS THE GREAT
LAKES REGION TONIGHT AMPLIFIES AS IT SHIFTS EWD WITH LOW CENTER
ACROSS SERN ONTARIO AT 18Z SUNDAY...AND THEN LIFTS NEWD ACROSS
SRN QUEBEC DURING THE DAY MONDAY. MAIN IMPACT WILL BE COOLER
TEMPERATURES ACROSS THE NORTH COUNTRY WITH THIS FEATURE.
SECONDARY FRONTAL BNDRY CROSSES THE REGION FROM W-E DURING SUNDAY
AFTN AND MAY BRING ISOLD/SCATTERED LIGHT RAIN SHOWERS. MOST OF
THIS ACTIVITY WILL BE HIT OR MISS AND KEPT POPS GENERALLY ON THE
LOW SIDE (20-30 PERCENT). STEEP LAPSE RATES AND MODERATE GRADIENT
FLOW COULD YIELD SOME WIND GUSTS 35-40 MPH ACROSS THE NRN
ADIRONDACKS AND ST. LAWRENCE VALLEY. SHOULD REMAIN BELOW WIND
ADVISORY CRITERIA...BUT WILL BE BREEZY FOR MUCH OF SUNDAY
AFTN...ESPECIALLY ACROSS NRN NY. HIGHS SUNDAY AFTN GENERALLY IN
THE LOW-MID 50S ACROSS NRN NY...BUT INTO THE LOWER 60S FOR THE
VALLEYS OF VT...AND CLOSER TO 64-65F IN THE CT RIVER VALLEY.
ADDITIONAL LOW-LEVEL COLD ADVECTION SUNDAY NIGHT BRINGS 850MB
TEMPS OF -7 TO -8C ACROSS LAKE ONTARIO WITH SUFFICIENT LAKE
INDUCED INSTABILITY TO GENERATE SOME LAKE EFFECT RAIN/SNOW
SHOWERS DURING SUNDAY NIGHT. HAVE INDICATED A REGION OF 40-60
POPS ACROSS SRN ST. LAWRENCE INTO SRN FRANKLIN COUNTY NY DURING
SUNDAY NIGHT TO ACCOUNT FOR THIS LAKE EFFECT ACTIVITY. COULD SEE
A LIGHT COATING OF SNOW IN THE ADIRONDACKS 06-12Z MONDAY WITH
LOWS AROUND 30-32F. ELSEWHERE...NOT MUCH FORCING FOR ASCENT...SO
REMAINDER OF THE FORECAST AREA SHOULD BE DRY WITH LOWS IN THE MID
30S. ENOUGH GRADIENT WIND IN THE CHAMPLAIN VALLEY SHOULD PRECLUDE
ANY FROST POTENTIAL FOR SUNDAY NIGHT WHERE THE GROWING SEASON IS
CONSIDERED ACTIVE.
ON MONDAY...MID-LEVEL TROUGH AXIS SHIFTS EWD ACROSS THE REGION
WITH 850MB TEMPS AROUND -4C. SHOULD BE THE COOLEST DAY OF THE
STRETCH WITH VALLEY HIGH TEMPERATURES MONDAY ONLY IN THE LOW-MID
50S. STEEP LAPSE RATES MAY YIELD A FEW SHOWERS WITH DAYTIME
HEATING...ESPECIALLY OVER THE NRN MTNS. OTHERWISE...ANTICIPATE A
MIX OF SUN AND CLOUDS ACROSS THE REGION.
SFC RIDGE AXIS CRESTS OVERHEAD DURING MONDAY NIGHT WITH
ASSOCIATED LIGHT WINDS AND CLEARING SKIES. GROWING SEASON IS
UNDERWAY IN THE CHAMPLAIN VALLEY...AND ANTICIPATE PATCHY FROST
FORMATION WITH LOWS 33-35F THAT MAY REQUIRE COVERING OF TENDER
VEGETATION. HAVE INCLUDED MENTION IN THE HAZARDOUS WEATHER
OUTLOOK AND IN THE FORECAST AT THIS TIME.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 430 PM EDT SATURDAY...PROGRESSIVE UPPER LEVEL FLOW SETS UP
ACROSS THE NORTH COUNTRY FOR THE TUESDAY THROUGH SATURDAY TIME
FRAME. THERE WILL BE SEVERAL CHANCES FOR SHOWERS AS BLOCKING
PATTERN SETS UP TO OUR EAST AND WILL CAUSE SEVERAL SHORTWAVES TO
CROSS OUR FORECAST AREA. DEVELOPING OMEGA BLOCK OVER THE NORTH
CENTRAL ATLANTIC OCEAN AND HEAT RIDGE ACROSS SOUTHEASTERN UNITED
STATES KEEPS NORTHEAST US RIGHT ALONG THE PERIPHERY OF A BUILDING
UPPER RIDGE. IN THE THU-SAT TIME FRAME A LOW PRESSURE SYSTEM WILL
PASS NORTH OF THE REGION AND BRING CHANCE FOR SHOWERS TO THE AREA.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 00Z MONDAY...VFR CONDITIONS WILL START THE PERIOD WITH A
TREND TOWARD VFR/MVFR CEILINGS WITH QUITE A BIT OF CLOUD COVER
UPSTREAM. VISIBILITIES WILL REMAIN IN THE VFR CATEGORY THROUGH THE
PERIOD. WEST TO SOUTHWEST WINDS WILL DIMINISH A BIT OVERNIGHT...THEN
INCREASE A LITTLE ON SUNDAY WITH STRONGER WIND GUSTS OVER THE SAINT
LAWRENCE VALLEY OF NEW YORK AFTER 18Z...GENERALLY IN THE 25 TO 35
KNOT RANGE.
OUTLOOK 00Z MONDAY THROUGH WEDNESDAY...
00Z MONDAY THROUGH 00Z TUESDAY...MAINLY VFR THOUGH SPOTTY
INSTABILITY-DRIVEN LIGHT SHOWERS COULD PRODUCE MVFR PERIODS.
00Z TUESDAY THROUGH THURSDAY...VFR UNDER HIGH PRESSURE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...BANACOS
NEAR TERM...EVENSON/LOCONTO
SHORT TERM...BANACOS
LONG TERM...NEILES
AVIATION...EVENSON/NEILES
AREA FORECAST DISCUSSION...UPDATED
NWS PENDLETON OR
1025 PM PDT SAT MAY 11 2013
UPDATED AVIATION DISCUSSION
.UPDATE...THE UPPER LEVEL HIGH PRESSURE RIDGE THAT HAS BROUGHT
UNSEASONABLY HOT CONDITIONS FOR SEVERAL DAYS IS SHIFTING
EASTWARD...AND THE UPPER FLOW IS BACKING TO THE SOUTHWEST. HIGH
LEVEL CLOUDS HAVE SPREAD THROUGHOUT WA/OR WHICH WILL KEEP
OVERNIGHT LOWS VERY MILD. LOW TEMPERATURES MAY NEED TO BE
INCREASED IN SEVERAL ZONES. FORECAST WAS UPDATED TO REMOVE
THUNDERSTORMS THIS EVENING EXCEPT IN THE HIGHER TERRAIN...BUT
THERE IS NO INDICATION OF ANY CONVECTIVE ACTIVITY SO WILL REMOVE
ALTOGETHER FOR THIS EVENING. HOWEVER...THERE WILL BE ELEVATED
INSTABILITY OVERNIGHT...AND THE HRRR AND OTHER RAP INSTABILITY
PARAMETERS HAVE HINTED ON SOME CONVECTIVE PRECIPITATION MOVING
ACROSS THE AREA. BASED ON PREVIOUS HRRR RUNS...I ADDED A SLIGHT
CHANCE OF THUNDERSTORMS OVERNIGHT TO CENTRAL AND NORTH CENTRAL
OREGON AND SPRINKLES TO THE LOWER COLUMBIA BASIN AND BLUE MOUNTAIN
FOOTHILLS EARLY SUNDAY MORNING. IT COULD BE ALTOCUMULUS
CASTELLANUS CLOUDS...BUT WILL NOT RULE OUT SOME VERY LIGHT
PRECIPITATION OR A HIGH BASED THUNDERSTORM OR TWO. THE LATEST HRRR
IS FARTHER WEST WITH THE SMALL BAND OF CONVECTIVE PCPN...BUT WILL
KEEP WHERE THE ELEVATED INSTABILITY IS GREATEST. WISTER
&&
.AVIATION...06Z TAFS. BROKEN MID AND HIGH LEVEL CLOUDS WITH VARYING
BASES ABOVE 10K FEET WILL BLANKET THE REGION THROUGH THE PERIOD.
DUE TO ELEVATED INSTABILITY...THERE WILL LIKELY BE ACCAS CLOUDS
EARLY SUNDAY MORNING. CUMULUS CLOUDS WITH BASES AROUND 6K FEET ARE
POSSIBLE SUNDAY AFTN/EVE. WINDS WILL INCREASE SUNDAY AND WILL BE
SUSTAINED AT 10-15 KNOTS GUSTING TO 20-25 KNOTS. THERE IS A SLIGHT
CHANCE OF THUNDERSTORMS OVER THE CENTRAL AND NORTHEAST MOUNTAINS
SUNDAY. WISTER
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 59 80 53 69 / 10 20 30 40
ALW 63 82 57 72 / 10 20 30 40
PSC 61 85 57 74 / 10 20 20 30
YKM 60 81 52 72 / 10 20 20 30
HRI 58 82 55 74 / 0 20 20 30
ELN 59 76 51 68 / 10 30 20 30
RDM 55 81 48 67 / 20 20 20 20
LGD 52 80 50 70 / 10 30 30 40
GCD 51 81 50 71 / 10 30 30 40
DLS 60 76 53 69 / 10 40 30 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
&&
THREAT INDEX
SUNDAY : GREEN
MONDAY : YELLOW
TUESDAY : GREEN
GREEN: NONE OR LIMITED NEED FOR WATCHES, WARNINGS, OR ADVISORIES.
YELLOW: A FEW WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
RED: NUMEROUS WATCHES, WARNINGS, OR ADVISORIES POSSIBLE OR IN EFFECT.
FOR ADDITIONAL WEATHER INFORMATION, CHECK OUR WEB SITE AT...
WWW.WEATHER.GOV/PENDLETON
$$
85
AREA FORECAST DISCUSSION
NWS SPOKANE WA
919 PM PDT Sat May 11 2013
.SYNOPSIS...
Changes in the weather pattern will arrive on Sunday with the
arrival of a cold front. There will be a chance of showers and
thunderstorms Sunday and again on Monday. The best chances however
will be on Monday...with some thunderstorms possibly strong to severe.
Gusty winds will be possible Sunday and Monday as well. Temperatures
will return closer to average by Monday. Tuesday and Wednesday
should be mainly dry over the Inland Northwest. A return of showers
is expected Thursday or Friday.
&&
.DISCUSSION...
Overall the forecast for tonight looks in good shape with only
very minor upward temperature adjustments for a few locations.
Abundant mid and high level clouds passing through the area will
reduce radiational cooling potential tonight which will allow for
a very mild night. For most locations...lows in the mid 50s to
lower 60s will end up being around 15 degrees above normal.
For Sunday...most model guidance shows only marginal instability
for showers...and especially thunderstorm development as a
weakening front crosses the Cascades in the afternoon. However
ahead of the front the NAM model continues to show an area of
negative 700-500mb theta-e lapse rates with elevated CAPES of
50-100 J/KG mainly east of a line from Moses Lake to Republic in
the morning. This could result in a stray lightning strike...but
more likely just high based shower activity with just sprinkles
reaching the ground. The latest 02z HRRR supports this idea. All
in all...Sunday likely will be dry for most of the day for most
locations in the Inland Northwest with temperatures still well
above normal. However enough instability and mid level moisture
will be present to warrant a chance for showers that could moves
over areas for a brief duration. The front will also bring
breezy to locally windy conditions Sunday afternoon. JW
&&
.AVIATION...
06Z TAFS: Mid and high clouds will continue to move into the Inland
Northwest through 06z Monday. High pressure will begin to shift
east on Sunday with a weak cold front passage. This may provide
enough lift for a better chance for showers and isolated thunderstorms
mainly over Northeast Washington and the North Idaho Panhandle.
However models have backed off a bit on the coverage of showers
and instability such that most...if not all...TAF sites may stay
dry through Sunday evening. The front will kick up some gusty
winds...with southwest winds gusting to 15-25 kts for most TAF
sites. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 80 55 69 43 63 / 10 30 20 60 50 10
Coeur d`Alene 57 79 54 69 43 61 / 0 30 40 60 60 10
Pullman 58 79 52 68 40 60 / 10 20 40 70 50 10
Lewiston 62 87 59 76 47 69 / 10 20 40 70 50 0
Colville 55 84 50 72 41 68 / 0 50 20 50 70 20
Sandpoint 53 78 52 69 41 61 / 0 50 40 60 90 20
Kellogg 59 79 52 68 42 57 / 0 40 50 80 70 20
Moses Lake 62 85 56 74 46 73 / 10 20 10 40 20 0
Wenatchee 62 80 56 70 46 69 / 10 20 10 40 20 0
Omak 56 81 51 71 41 70 / 10 10 10 50 40 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
345 AM CDT SUN MAY 12 2013
.TODAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
NOT AS MUCH INSTABILITY OR DYNAMIC PUNCH AS THERE WAS
YESTERDAY...BUT STILL HAVE THE THE WESTERN EDGE OF THE COLD POOL
OVER US...ESPECIALLY OVER THE EASTERN CWA THIS MORNING. SHOULD SEE
CU POP BY MID MORNING. RAP SOUNDINGS SHOW A DEEPER CLOUD LAYER
THAN NAM OR GFS...WITH SOME MINIMAL CAPE DEVELOPING SOME SPRINKLES
IN THE SOUTHEAST IN THE AFTERNOON. WILL LEAVE OUT FOR NOW...BUT
WILL NEED TO BE WATCHED WITH SHEARED VORT DROPPING THROUGH REGION
THIS AFTERNOON PROVIDING A BIT OF EXTRA LIFT. THE COLD AIR
ADVECTION HAS BROUGHT 925 MB TEMPERATURES DOWN TO -1C TO -4C...BUT
MODELS AGREE THAT THEY WILL RECOVER TO +3 TO +5C BY 00Z. THOUGH
WARMEST 925 MB TEMPS WILL ARRIVE TOWARD THE END OF THE
DAY...ENOUGH OF AN INFLUENCE TO LEAN TOWARD WARMER GUIDANCE WITH
MID 50S IN THE WEST...TO AROUND 50 IN THE FAR EAST.
.TONIGHT...FORECAST CONFIDENCE...HIGH
GIVEN THE EXPECTED GOOD RADIATIONAL COOLING CONDITIONS AS SURFACE
RIDGE AXIS MOVES OVER THE STATE TONIGHT ...AND WITH BUFKIT SOUNDINGS
SUPPORTING THE THE NAM/GFS 2-METER TEMPERATURES AND MOS GUIDANCE...
WILL ISSUE A FREEZE WARNING FOR THE FAR NW COUNTIES WHERE LOWS TO
BOTTOM OUT IN THE UPPER 20S...AND A FROST ADVISORY FOR THE REST OF
THE CWA WITH LOW 30S AWAY FROM THE IMMEDIATE LAKESHORE. EVEN
MILWAUKEE AND OZAUKEE COUNTIES SHOULD SEE AREAS OF FROST IN THEIR
FAR WEST. THE LOWEST TEMPERATURES ARE CURRENTLY LIMITED TO NORTHERN
SECTIONS OF THE FREEZE WARNING COUNTIES...BUT WARNING WOULD HAVE TO
BE EXPANDED IF THE COLDER NAM IS CORRECT.
.MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
THE AXIS OF SURFACE HIGH PRESSURE WILL BE OVERHEAD MONDAY
MORNING...SO THERE SHOULD BE PLENTY OF SUNSHINE TO START THE DAY.
THE HIGH WILL SLIDE EAST DURING THE DAY...WITH STRONG WARM ADVECTION
ALOFT SLIDING INTO THE WEST BY LATE AFTERNOON. THIS WILL BRING
INCREASING CLOUDS ALONG WITH A CHANCE FOR SHOWERS TO MAINLY WESTERN
PORTIONS OF THE FORECAST AREA.
THE MAX OF THE WARM ADVECTION WILL SLIDE THROUGH MAINLY DURING THE
EVENING HOURS...SO KEPT HIGHEST POPS DURING THAT PERIOD. SHOULD BE
MAINLY DRY THEN TUESDAY AS A WARMER AND CAPPED AIRMASS MOVES INTO
THE FORECAST AREA.
THE SURFACE COLD FRONT IS EXPECTED TO DROP THROUGH SOUTHERN
WISCONSIN TUESDAY EVENING AND OVERNIGHT. MODELS ARE NOT SHOWING MUCH
LIFT WITH THIS FRONT...SO KEPT POPS ON THE LOW END.
TEMPERATURES MONDAY WILL CLIMB BACK TOWARD NORMAL VALUES UNDER
SOUTHERLY WINDS BEHIND THE EXITING HIGH PRESSURE. MUCH WARMER
TEMPERATURES ARE THEN EXPECTED TUESDAY...WITH HIGH TEMPERATURES
EXPECTED TO CLIMB WELL ABOVE NORMAL INTO THE 80S ACROSS THE WESTERN
FORECAST AREA. THERE IS MUCH LESS CERTAINTY WITH TEMPERATURES IN THE
EAST THOUGH. MODELS VARY A BIT ON THE TIMING OF THE SYSTEM...THUS
IMPACTING WIND DIRECTION. IF THE WINDS STAY SOUTHEAST THROUGH THE
DAY AS THE SLOWER ECMWF SUGGESTS...HIGH TEMPS WILL LIKELY BE COOLER
THAN WHAT IS CURRENTLY FORECAST. THE QUICKER NAM AND CANADIAN WOULD
HAVE SOUTHWEST WINDS FOR A GOOD PART OF THE DAY...RESULTING IN
WARMER TEMPS THAN FORECAST. OPTED TO GO DOWN THE MIDDLE FOR TEMPS
TOWARD THE LAKE FOR NOW UNTIL MODELS COME INTO BETTER AGREEMENT.
THOUGH THE SURFACE FRONT WILL LIKELY HAVE PUSHED SOUTH BY WEDNESDAY
MORNING...MODELS ARE STILL SHOWING A FAIR AMOUNT OF WARM AIR
LINGERING ACROSS SOUTHERN WISCONSIN. HIGH TEMPS ARE THUS EXPECTED TO
REMAIN ABOVE NORMAL.
.THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE...LOW TO MEDIUM
HAVE SHOWER AND STORM CHANCES THROUGH THE LATTER HALF OF THE WEEK AS
MODELS CONTINUE TO SHOW THE FRONTAL BOUNDARY STALLING IN THE AREA.
WILL LIKELY SEE SYSTEMS MOVE THROUGH ALONG THE BOUNDARY. BIGGEST
ISSUE IS HOW FAR SOUTH THE BOUNDARY WILL STALL AND THEN TIMING OF
THE INDIVIDUAL SYSTEMS AND RESULTANT PRECIP CHANCES.
ALSO...DIFFERING PLACEMENTS OF THE STALLED FRONT ARE PRODUCING
DECENT SPREADS IN TEMPS AMONG MODELS. NOT A HIGH CONFIDENCE
SETUP...SO STUCK WITH A CONSENSUS APPROACH FOR TEMPERATURES.
&&
.AVIATION/12Z TAFS/...
SHOULD SEE VFR CU DEVELOP/4-5K FT/ BY MID-MORNING AND BECOME BROKEN.
WINDS WILL BE GUSTY TO START AFTER MORNING MIX OUT...THEN SLOWLY
SUBSIDE THROUGH THE AFTERNOON AND REALLY EASE THIS EVENING AS
SURFACE RIDGE BUILDS INTO THE AREA. VFR FOR REMAINDER OF THE PERIOD
WITH LIGHT WINDS AND CLEAR SKIES TONIGHT.
&&
.MARINE...
CURRENT FORECAST WIND GUSTS STILL INDICATE 3 PM CDT END TIME FOR
SMALL CRAFT ADVISORY HOLDS...THOUGH THERE COULD BE A FEW CRITERIA
GUSTS UNTIL AFTER SUNSET...ESPECIALLY IN THE NORTHERN ZONES. WINDS
WILL EASE TONIGHT AS SURFACE RIDGE PASSES THROUGH...TURNING SOUTH
MONDAY AFTERNOON AND INCREASING MONDAY NIGHT AHEAD OF NEXT LOW.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ051-052-
057>060-062>072.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ046-047-056.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR
LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
320 AM CDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MAIN FORECAST CONCERN IS ON FROST/FREEZE CONDITIONS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO ALBERTA WHILE ANOMALOUSLY
DEEP TROUGHING WAS PRESENT FROM HUDSON BAY INTO THE WESTERN GREAT
LAKES REGION. THE FORECAST AREA LIES ON THE BACK SIDE OF THE
TROUGHING...BUT STILL EAST OF THE INFLECTION POINT...WHICH RESULTS
IN NORTHWEST FLOW FROM THE SURFACE TO 500MB. THE FLOW CONTINUED TO
DRAG COLDER AIR SOUTHEAST WITH RAP 850MB TEMPS RANGING FROM -3C OVER
NORTHEAST IOWA TO -9C IN TAYLOR COUNTY WISCONSIN. DESPITE THE COLD
850MB TEMPS...READINGS ARE GENERALLY IN THE MID 30S TO AROUND 40...
STAYING UP BECAUSE OF THAT NORTHWEST WIND OF 5-10 KT AT THE SURFACE
KEEPING THE BOUNDARY LAYER MIXED. A LOT OF DRY AIR CONTINUES TO FLOW
IN TOO ON THE NORTHWEST WINDS FROM HIGH PRESSURE IN THE PLAINS.
DEWPOINTS ARE IN THE TEENS ACROSS MUCH OF THE DAKOTAS INTO MN AND
20S OVER WISCONSIN. COMBINATION OF THE WIND...TEMPERATURES AND DRY
AIR PRECLUDING ANY FROST DEVELOPMENT THUS FAR. THE AFOREMENTIONED
DRY AIR IS ALSO QUITE DEEP...REFLECTIVE FROM 00Z SOUNDINGS AT BIS...
ABR AND MPX HAVING PRECIPITABLE WATER VALUES OF 0.1-0.2 INCHES...OR
20-40 PERCENT OF NORMAL. THIS DRY AIR HAS HELPED CLEAR SKIES OUT
WEST OF WISCONSIN. SCT-BKN CLOUDS HAVE BEEN FLOWING ACROSS WISCONSIN
IN THE CYCLONIC FLOW IN THE UPPER TROUGH. FARTHER TO THE WEST UNDER
THE UPPER RIDGE...00Z SOUNDINGS FROM SAN FRANSISCO TO SALT LAKE CITY
AND NORTH TO GREAT FALLS MT ALL REPORTED 850MB TEMPS OF 20C OR
GREATER. THESE ARE 1.5-2.5 STANDARD DEVIATIONS ABOVE NORMAL.
BOTH THE UPPER RIDGE AND ANOMALOUSLY DEEP TROUGH ARE PROGGED TO
PROGRESS EASTWARD DURING THE NEXT 24 HOURS...PUSHED ALONG BY A
FAIRLY POTENT SHORTWAVE TROUGH APPROACHING THE PACIFIC NORTHWEST
COAST AT 12Z MONDAY. IT APPEARS THIS EVENING IS WHEN THE INFLECTION
POINT BETWEEN THE UPPER RIDGE AND DEEP TROUGH WILL REACH THE
FORECAST AREA. THIS MEANS TO PLAN ON THE SURFACE HIGH OVERHEAD AT
ABOUT THE SAME TIME.
TODAY...THE COMBINATION OF DRY AIR AND BEING FARTHER AWAY FROM THE
COLD POOL OF THE UPPER TROUGH WILL RESULT IN SUNNY SKIES. SINCE THE
AREA STAYS IN A GRADIENT AHEAD OF THE SURFACE HIGH AND WE HAVE FULL
SUN FOR DEEP MIXING...ANOTHER BREEZY DAY IS LIKELY...BUT NOT NEARLY
AS WINDY AS YESTERDAY. TEMPERATURES ARE DEFINITELY GOING TO STAY ON
THE COOL SIDE...THOUGH...WITH 850MB TEMPS HOLDING STEADY THROUGH
18Z. HIGHS SHOULD END UP VERY SIMILAR TO YESTERDAY.
TONIGHT...A REALLY GOOD RADIATIONAL COOLING SETUP IS FORECAST. WITH
THE SURFACE HIGH MOVING OVER THE AREA DURING THE EVENING...WINDS
WILL DECOUPLE EVERYWHERE. ADDITIONALLY...WE HAVE ALL OF THE DRY AIR
ACCOMPANYING THE SURFACE HIGH. THUS...TEMPERATURES SHOULD PLUMMET
DURING THE EVENING HOURS AFTER SUNSET. NOW...AFTER MIDNIGHT...THE
SURFACE RIDGE BEGINS TO PUSH EAST INTO CENTRAL WISCONSIN. THIS MEANS
A SOUTHERLY WARM ADVECTION FLOW WILL COMMENCE OVER WESTERN PORTIONS
OF THE FORECAST AREA. THEREFORE...OUR WISCONSIN COUNTIES CONTINUE TO
LOOK THE MOST FAVORABLE FOR THE COLDEST CONDITIONS...AND THE COLDEST
OVERALL OVER CENTRAL WISCONSIN. STAYED TOWARDS THE COLD SIDE OF
GUIDANCE FOR LOWS. GIVEN THE CONSISTENCY FOR TONIGHT TO BE COLD...
HAVE ISSUED FREEZE WARNINGS FOR THE PREVIOUS FREEZE WATCH AREA AND A
FEW EXTRA COUNTIES WHERE TEMPS ARE NOW FORECAST COLDER...WITH FROST
ADVISORIES FOR THE REST OF OUR WISCONSIN COUNTIES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING OVER THE WESTERN
U.S. IS PROGGED TO CONTINUE TO GET PUSHED EASTWARD WHILE FLATTENING
WITH TIME. THIS IN RESPONSE TO THE POTENT SHORTWAVE OFF THE PACIFIC
NORTHWEST AT 12Z MONDAY TRACKING EASTWARD ALONG THE U.S./CANADIAN
BORDER. OVERALL MODELS ARE IN PRETTY GOOD AGREEMENT ON THE TRACK AND
SPEED OF THIS SHORTWAVE...WITH THE EXCEPTION OF THE 12.00Z NAM
WHICH BECOMES SLIGHTLY FASTER COME TUESDAY AND TUESDAY NIGHT. HAVE
DISCOUNTED THE NAM PROGRESSION AS AN OUTLIER FOR NOW. THE
PROGRESSIVE NATURE OF THE RIDGE AND SHORTWAVE RESULTS IN A VARIETY
OF ISSUES TO CONTEND WITH...
1. PRECIPITATION CHANCES AND TEMPERATURES MONDAY INTO MONDAY NIGHT.
A WARM FRONT AHEAD OF THE UPPER RIDGE AXIS IS FORECAST TO CROSS THE
AREA MONDAY NIGHT. PACIFIC MOISTURE MOVING THROUGH THE UPPER RIDGE
IN CONJUNCTION WITH ISENTROPIC LIFT AHEAD OF THIS WARM FRONT WILL
LIKELY TO LEAD TO EXTENSIVE MID AND HIGH CLOUDS. ADDITIONALLY...THE
LIFT APPEARS STRONG ENOUGH TO GENERATE PRECIPITATION FROM THESE
CLOUDS. THE BIG PROBLEM...THOUGH...IS LOW LEVEL DRY AIR LEFT OVER
FROM THE CURRENT CANADIAN HIGH PRESSURE AREA. OVERALL...12.00Z MODEL
GUIDANCE HAS BACKED OFF ON THE AMOUNT OF QPF POSSIBLE FROM THESE
CLOUDS...ESPECIALLY THE GFS...SUGGESTING THE DRY AIR MAY BE ABLE TO
ABSORB MUCH OF THE PRECIPITATION. HOWEVER...ALL GUIDANCE DOES
SUGGEST SOME LIGHT QPF POSSIBLE...THUS THE 20-40 PERCENT CHANCES
FROM THE PREVIOUS FORECAST STILL SEEMS REASONABLE. TIMING BETWEEN
18Z MONDAY TO 06Z TUESDAY ALSO STILL LOOKS GOOD. SHOULD SEE THE
CLOUDS AND PRECIPITATION PROGRESS EASTWARD THROUGH TIME DUE TO THE
PROGRESSION OF THE UPPER RIDGE. THE CLOUDS COMBINED WITH 850MB TEMPS
AT 18Z MONDAY OF 1C EAST TO 6C WEST ARE LIKELY TO KEEP TEMPERATURES
BELOW NORMAL...BUT NOT AS COLD AS TODAY.
2. HOW WARM TEMPERATURES WILL GET ON TUESDAY. THE SIGNAL OF A
CHINOOK WARM FRONT OFF THE ROCKIES...ACCOMPANYING THAT POTENT
SHORTWAVE...REMAINS FORECAST TO PUSH EAST THROUGH MUCH OF THE
FORECAST AREA DURING THE DAY TUESDAY. INCREDIBLY WARM 850MB TEMPS
FOR MID MAY ARE PROGGED TO FOLLOW IN ITS WAKE...WITH READINGS BY 00Z
OF 18-20C OVER CENTRAL WISCONSIN TO 22-24C WEST OF THE MISSISSIPPI
RIVER...OR 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. SEEING THE
OBSERVED 850MB TEMPS UNDER THE UPPER RIDGE RIGHT NOW OVER THE
WESTERN U.S...THESE SEEM REASONABLE. THE QUESTION IS WITH A WARM
ADVECTION PATTERN THROUGH THE DAY...CAN WE MIX TO THESE 850MB TEMPS.
MODELS CONTINUE TO BE NOTORIOUSLY HIGH WITH SURFACE DEWPOINTS IN
THIS SITUATION...PREVENTING MODELS FROM MIXING ENOUGH. FOR
EXAMPLE...THE 12.00Z GFS/ECMWF/CANADIAN JUMP THEM OVER IOWA FROM
50-55 AT 12Z TO 60-65 AT 18Z...ALL LIKELY DUE TO EVAPOTRANSPORATION
THAT IS NOT THERE YET. ADDITIONALLY...A DOWNSLOPE FLOW FROM THE
ROCKIES USUALLY ENDS UP WITH DRIER DEWPOINTS...ESPECIALLY THIS TIME
OF YEAR. THUS...HAVE CONTINUED TO STAY TOWARDS THE WARM SIDE OF
GUIDANCE. ALTHOUGH THE 12.00Z NAM IS SLIGHTLY TOO PROGRESSIVE...ITS
TEMPERATURES SEEM REASONABLE. FOLLOWED MOS GUIDANCE MORE FOR
DEWPOINTS SINCE MOS HAS BEEN DOING MUCH BETTER IN THIS DEPARTMENT.
3. COLD FRONT CROSSING TUESDAY NIGHT AND POTENTIAL FOR PRECIPITATION
WITH IT. 12.00Z NAM AND GFS ARE JUST SLIGHTLY FARTHER SOUTH WITH THE
TRACK OF THE SHORTWAVE TRACKING ALONG THE CANADIAN BORDER...COMPARED
TO THE 12.00Z ECMWF/UKMET/CANADIAN. THIS DIFFERENCE RESULTS IN THE
NAM/GFS ADDING EXTRA FORCING TO THE LOW LEVEL FRONTOGENESIS ZONE ON
AND BEHIND THE COLD FRONT...AND THUS THE MODELS PRODUCE A BAND OF
PRECIPITATION OVER THE AREA. THE ECMWF/UKMET/CANADIAN ARE DRY. FEEL
THE LATTER MODEL GROUP IS MORE LIKELY TO OCCUR...BUT CONTINUED TO
HONOR THE NAM/GFS SCENARIO WITH A 20 PERCENT CHANCE JUST IN CASE.
WEDNESDAY INTO NEXT WEEKEND...
GOOD MODEL AGREEMENT EXISTS OF THE FLOW STARTING OFF AS ZONAL TO
BEGIN THIS PERIOD. ANY LOW LEVEL FRONTOGENETICAL FORCING BEHIND
TUESDAY NIGHTS COLD FRONT IS SOUTH OF THE AREA FOR WEDNESDAY...SO
WENT DRY DURING THIS TIME. THE ZONAL FLOW DOES NOT LAST LONG...WITH
A NEW TROUGH PROGGED TO COME INTO THE PACIFIC NORTHWEST THURSDAY
NIGHT. THIS CAUSES THE FLOW DOWNSTREAM TO BUCKLE...WITH THE 12.00Z
ECMWF/GFS/CANADIAN ALL SHOWING A SHORTWAVE TROUGH TRACKING ACROSS MN
AND WI THURSDAY INTO THURSDAY NIGHT. HAVE HONORED THE SHORTWAVE WITH
SOME SMALL CHANCES OF PRECIPITATION. WE COULD END UP WITH A DRY DAY
FRIDAY WITH SUBSIDENCE AND HIGH PRESSURE BUILDING IN. LOWERED
PRECIPITATION CHANCES FURTHER AND MAY BE ABLE TO COMPLETELY PULL
THEM WITH THE NEXT EXTENDED FORECAST UPDATE. THINGS LOOK TO PERHAPS
TO GET MORE ACTIVE FOR FRIDAY NIGHT INTO THE WEEKEND AS THE PACIFIC
NORTHWEST TROUGH BEGINS TO APPROACH THE PLAINS. SURPRISINGLY GOOD
MODEL AGREEMENT BETWEEN THE ECMWF AND GFS...ALONG WITH PREVIOUS
RUNS...OF A DEEPENING LOW DOWNSTREAM OVER NEBRASKA. AS ONE WOULD
EXPECT...A SURGE OF MOISTURE TRANSPORT OUT OF THE GULF OF MEXICO IS
AIMED DIRECTLY TOWARDS THE FORECAST AREA AHEAD OF THE LOW.
THUS...PRECIPITATION CHANCES INCREASE...ESPECIALLY ON SATURDAY WHERE
THE CONSENSUS EVEN RESULTS IN 50-60 PROBABILITIES. TEMPERATURES
SHOULD SLOWLY COOL THROUGH THE EXTENDED...BUT STILL STAY AT OR ABOVE
NORMAL WITH A FLOW GENERALLY OFF THE PACIFIC.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1015 PM CDT SAT MAY 11 2013
CLOUDS AND -SHRA HAVE DISSIPATED FOR KRST/KLSE EARLY IN THE
EVENING...WHILE WINDS WERE LESSENING WITH THE LOSS OF MIXING FROM
DAYTIME HEATING. THE WINDS WILL CONTINUE TO DECREASE OVERNIGHT AS
HIGH PRESSURE APPROACHES FROM THE WEST...ALLOWING FOR THE SFC
PRESSURE GRADIENT TO SLACKEN. HOWEVER...EXPECTED SUNSHINE ON SUNDAY
WILL RESULT IN MORE MIXING. EXPECT SOME GUSTS SUNDAY AFTERNOON...BUT
ABOUT 1/2 OF WHAT THEY WERE TODAY. VFR CONDITIONS WILL BE THE RULE
THROUGH SUNDAY NIGHT AS THAT HIGH SETTLES OVERHEAD.
CLOUDS WILL RETURN ON MONDAY AS AN UPPER LEVEL SHORTWAVE TROUGH
MOVES ACROSS NORTHERN PORTIONS OF THE UPPER MISSISSIPPI RIVER
VALLEY. A FEW SHOWERS WILL DEVELOP ALONG ITS ASSOCIATED WARM
FRONT...BUT THESE SHOULD STAY NORTH OF KRST/KLSE. LOOK FOR MUCH
WARMER CONDITIONS FOR TUE/WED POST THE FRONT.
&&
.FIRE WEATHER...TUESDAY
ISSUED AT 320 AM CDT SUN MAY 12 2013
AFTER HAVING BREEZY...DRYING AND UNSEASONABLY COOL WEATHER THIS
WEEKEND...INCLUDING FROST/FREEZE CONDITIONS TONIGHT ACROSS
WISCONSIN...CONCERN CONTINUES TO INCREASE ABOUT CRITICAL FIRE
WEATHER CONDITIONS ON TUESDAY. MOST LOCATIONS SHOULD SEE HIGHS
CLIMB INTO THE 80S...WITH SOME WEST OF THE MISSISSIPPI RIVER
REACHING 90. DEWPOINT FORECASTS REMAIN TRICKY...BUT MINIMUM
RELATIVE HUMIDITY VALUES SHOULD HAVE NO PROBLEM FALLING INTO THE
30 TO 40 PERCENT RANGE. IT IS POSSIBLE LOCATIONS SAY ALONG AND
WEST OF US-52 COULD END UP DROPPING TOWARDS 25 PERCENT. COMBINED
WITH SOUTHWEST WINDS OF 15 TO 20 MPH AND HIGHER GUSTS...THE
SITUATION BEARS WATCHING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ032-041-054-
061.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ017-029-033-
034-042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...RIECK
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS MIAMI FL
922 AM EDT SUN MAY 12 2013
.UPDATE...
NO CHANGES ARE PLANNED FOR THE MORNING UPDATES. THE 12Z MFL
SOUNDING SHOWS ONLY MODEST INSTABILITY WITH TWO SMALL INVERSIONS,
ONE AT AROUND THE 850 MB LEVEL AND ANOTHER AT 500 MB. THUS, IT
WOULD APPEAR THAT CONVECTION WILL STRUGGLE TO GET GOING MUCH LIKE
YESTERDAY AND MAY EVEN BE MORE SO TODAY. MODIFIED CAPE IS AROUND
1500 J/KG OR SLIGHTLY LESS AND THAT IS ALSO SIMILAR TO SATURDAY.
STEERING FLOW REMAINS WNW-ESE AT 5-7 KT AND BASED ON ALL OF THIS
THE HRRR DOES SHOW CONVECTION FIRING UP AT 18-19Z AND THEN
BUILDING AFTER 20Z AS IT DRIFTS TOWARDS THE EAST COAST METRO
REGION. SO ALL IN ALL, THE FORECAST LOOKS GOOD WITH A LATE
AFTERNOON/EARLY EVENING STRONG STORM POSSIBLY CAPABLE OF PRODUCING
A WIND GUST AND/OR SMALL HAIL ALTHOUGH THE PRIMARY RISK APPEARS TO
BE THE WIND GUSTS.
KOB
&&
.PREV DISCUSSION... /ISSUED 720 AM EDT SUN MAY 12 2013/
AVIATION...
CLEAR SKIES AND CALM WINDS THIS MORNING WILL GRADUALLY TRANSITION TO
SCATTERED/BROKEN CUMULUS WITH ONSHORE WINDS OF 10-15 KTS BY MIDDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED AWAY FROM THE GULF
COAST. HAVE ELECTED TO PLACE VCSH AT ALL AIRPORTS EXCEPT KAPF...DUE
TO LOW CONFIDENCE IN COVERAGE AND TIMING OF THUNDERSTORMS. GUSTY
WINDS AND SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS COULD OCCUR IN
AND NEAR SHOWERS AND THUNDERSTORMS THIS AFTERNOON. ACTIVITY LIKELY
DIMINISHES BY SUNSET...THEN CLEARING SKIES AND CALM WINDS TONIGHT.
FOG OVER INTERIOR SOUTH FLORIDA COULD IMPACT APF LATE TONIGHT...BUT
ATTM THIS RISK APPEARS LOW.
PREV DISCUSSION... /ISSUED 350 AM EDT SUN MAY 12 2013/
DISCUSSION...
AN UPPER TROUGH WAS DIGGING INTO THE SOUTHEAST THIS
MORNING...WITH MAINLY ZONAL FLOW ACROSS SOUTH FLORIDA. A SURFACE
LOW WAS LOCATED OVER CANADA TO THE NORTH OF THE GREAT LAKES AND A
COLD FRONT WAS MOVING INTO NORTHERN FLORIDA. WINDS NEAR THE
SURFACE ARE EXPECTED TO BE OUT OF THE SOUTH TO SOUTHEAST...WITH
WESTERLY FLOW ALOFT. THE MORE SOUTHERLY LOW LEVEL FLOW WILL PUSH
THE SEA BREEZE BOUNDARY NORTHWARD AWAY FROM THE SOUTHEAST
COAST...AND THE WESTERLY FLOW ALOFT WILL PUSH STORMS BACK TOWARDS
THE EAST COAST. LOW LEVEL MOISTURE WILL POOL SOUTH OF THE FRONTAL
BOUNDARY THIS AFTERNOON...WITH PWATS AROUND 1.6-1.7 INCHES. SO THE
BEST CHANCE OF RAIN WILL BE ACROSS PALM BEACH AND BROWARD
COUNTIES. SHEAR VALUES ARE NOT AS HIGH AS YESTERDAY...AND
TEMPERATURES ALOFT ARE SLIGHTLY WARMER AS WELL. HOWEVER...AS THE
TROUGH DIGS INTO THE SOUTHEAST AND NORTHERN FLORIDA...DIVERGENCE
ALOFT WILL INCREASE. SO STRONG STORMS WILL BE POSSIBLE...AND A
STRAY SEVERE STORM CANNOT BE RULED OUT ACROSS THE INTERIOR AND
ACROSS PALM BEACH COUNTY. THE MAIN THREAT WILL BE STRONG WINDS.
HIGHS WILL BE IN THE MID 80S COASTAL AREAS TO LOWER 90S INTERIOR.
THE FRONTAL BOUNDARY WILL MOVE INTO SOUTH FLORIDA MONDAY
MORNING...AND PATCHY FOG IS POSSIBLE...ESPECIALLY FOR THE
NORTHWESTERN HALF OF THE REGION. ALTHOUGH NOT CURRENTLY IN THE
FORECAST...DENSE FOG COULD ALSO OCCUR ACROSS THE NORTHWEST
INTERIOR. THE UPPER TROUGH WILL DIG DOWN THE PENINSULA...AND THE
REGION WILL MOVE INTO THE RIGHT ENTRANCE REGION OF A 100 KNOT
250MB JET STREAK. 0-6KM SHEAR WILL INCREASE TO AROUND 30 KNOTS AS
WELL. THE SURFACE BOUNDARY IS EXPECTED TO PUSH INTO DEEP SOUTH
FLORIDA AROUND 18Z WITH NORTHERLY LOW LEVEL FLOW. HOWEVER...DRY
AIR WILL LAG BEHIND ACROSS CENTRAL FLORIDA. AS THE EAST COAST SEA
BREEZE DEVELOPS...SCATTERED SHOWERS AND STORMS ARE EXPECTED TO
DEVELOP ALONG IT...WITH STORM MOTION TO THE SOUTH OR SOUTHEAST.
STRONG TO ISOLATED SEVERE STORMS ARE POSSIBLE..ESPECIALLY TOWARDS
THE SOUTHEAST PORTIONS OF THE AREA.
DRIER AIR WILL BEGIN TO MOVE INTO THE LAKE REGION IN THE LATE
AFTERNOON TO EARLY EVENING...WITH MUCH DRIER AIR ENCOMPASSING
SOUTH FLORIDA OVERNIGHT. PRECIPITABLE WATER VALUES WILL DROP TO
AROUND 0.75 INCHES...WHICH IS WELL BELOW NORMAL FOR THIS TIME OF
YEAR. SURFACE HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST AND
WESTERN ATLANTIC...AND BREEZY NORTHEASTERLY WINDS ARE EXPECTED ON
TUESDAY. TEMPERATURES TUESDAY MORNING WILL BE COOLER...ESPECIALLY
ACROSS THE NORTHWEST INTERIOR...WHERE LOWS WILL BE IN THE 50S. MID
60S TO AROUND 70 IS STILL EXPECTED FOR THE EAST COAST...BUT IT
WILL FEEL MUCH MORE COMFORTABLE AS DEWPOINTS DROP INTO THE 50S TO
AROUND 60. VERY PLEASANT MID MAY TEMPERATURES ARE EXPECTED ON
TUESDAY THROUGH THE END OF THE WEEK. HIGHS WILL BE NEAR 80 TO THE
MID 80S ON TUESDAY.
AN UPPER LEVEL RIDGE WILL BUILD TO THE EAST ACROSS THE GULF ON
WEDNESDAY AND HEIGHTS WILL INCREASE. HOWEVER...TEMPERATURES WILL
REMAIN AT OR BELOW NORMAL THROUGH THE END OF THE WEEK AS DRY AND
COOL EAST TO NORTHEASTERLY FLOW CONTINUES. PWATS WILL REMAIN AT
OR BELOW 1 INCH THROUGH THE END OF THE WEEK. A WEAK SHORTWAVE WILL
MOVE ACROSS THE SOUTHERN PLAINS AND INTO THE SOUTHEAST ON
THURSDAY...WITH WEAK TROUGHING THEN REMAINING OVER THE SOUTHEAST
AND FLORIDA INTO THE WEEKEND.
AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH EARLY THIS WEEK. MOSTLY CLEAR
SKIES AND NEAR-CALM WINDS EARLY THIS MORNING WILL GIVE WAY TO
INCREASING CUMULUS WITH SOUTHEAST BREEZES AT 10-15 KTS BY MIDDAY.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED DURING THE
AFTERNOON ACROSS SOUTH FLORIDA...MAINLY EAST OF NAPLES.
THUS...PROB30S MAINTAINED FOR EASTERN TERMINALS. GUSTY WINDS AND
SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS ARE LIKELY IN/NEAR
SHOWERS/THUNDERSTORMS. PRECIPITATION SHOULD DIURNALLY WANE THIS
EVENING...WITH CLEARING SKIES AND CALMING WINDS EXPECTED TODAY.
MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE TODAY OUTSIDE OF ISOLATED
STRONG CONVECTION. A COLD FRONT WILL MOVE ACROSS THE SOUTH FLORIDA
WATERS LATE MONDAY WITH STRONG HIGH PRESSURE BUILDING BEHIND THE
FRONT WITH INCREASING WIND AND SEAS MONDAY NIGHT INTO MID WEEK.
FIRE WEATHER...
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY
AND MONDAY...MAINLY DURING THE AFTERNOON AND EARLY EVENING
HOURS. A FRONT WILL BRING IN MUCH DRIER AIR MONDAY NIGHT INTO
TUESDAY. RELATIVE HUMIDITY VALUES ACROSS GLADES HENDRY AND
COLLIER COUNTIES MAY FALL BELOW 35 PERCENT BOTH TUESDAY AND
WEDNESDAY AFTERNOONS...WITH WINDS OF 10-15 MPH POSSIBLE. THERE IS
A SLIGHT CHANCE THAT PATCHY FOG WILL FORM LATE TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 86 69 85 65 / 60 30 30 10
FORT LAUDERDALE 87 74 85 69 / 50 20 50 20
MIAMI 88 72 86 69 / 40 20 50 20
NAPLES 86 71 86 64 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1106 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 16Z...
* NORTHWEST WINDS GUSTING TO 20-25KT TODAY
KREIN
//DISCUSSION...UPDATED 12Z...
WEATHER NOT EXPECTED TO ADVERSELY AFFECT AVIATION OPERATIONS
TODAY. NORTHWEST WINDS WILL ATTAIN SOME GUSTINESS BY MID MORNING
WITH GUSTS FAIRLY STEADY GUSTS OF 20 TO 25KT EXPECTED THROUGH THE
AFTERNOON. WINDS WILL QUICKLY SUBSIDE THIS EVENING. SCT V BKN VFR
DECK OF HIGH BASED STRATOCUMULUS LIKELY TO BLOSSOM THIS MORNING
AND LINGER INTO THE EARLY EVENING BEFORE SKIES GO CLEAR TONIGHT.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 16Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
910 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 14Z...
* NORTHWEST WINDS GUSTING TO 20-25KT TODAY
KREIN
//DISCUSSION...UPDATED 12Z...
WEATHER NOT EXPECTED TO ADVERSELY AFFECT AVIATION OPERATIONS
TODAY. NORTHWEST WINDS WILL ATTAIN SOME GUSTINESS BY MID MORNING
WITH GUSTS FAIRLY STEADY GUSTS OF 20 TO 25KT EXPECTED THROUGH THE
AFTERNOON. WINDS WILL QUICKLY SUBSIDE THIS EVENING. SCT V BKN VFR
DECK OF HIGH BASED STRATOCUMULUS LIKELY TO BLOSSOM THIS MORNING
AND LINGER INTO THE EARLY EVENING BEFORE SKIES GO CLEAR TONIGHT.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 14Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
WWW.FACEBOOK.COM/US.NATIONALWEATHERSERVICE.CHICAGO.GOV
WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
600 AM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* NORTHWEST WINDS GUSTING TO 20-25KT TODAY
IZZI
//DISCUSSION...UPDATED 12Z...
WEATHER NOT EXPECTED TO ADVERSELY AFFECT AVIATION OPERATIONS
TODAY. NORTHWEST WINDS WILL ATTAIN SOME GUSTINESS BY MID MORNING
WITH GUSTS FAIRLY STEADY GUSTS OF 20 TO 25KT EXPECTED THROUGH THE
AFTERNOON. WINDS WILL QUICKLY SUBSIDE THIS EVENING. SCT V BKN VFR
DECK OF HIGH BASED STRATOCUMULUS LIKELY TO BLOSSOM THIS MORNING
AND LINGER INTO THE EARLY EVENING BEFORE SKIES GO CLEAR TONIGHT.
IZZI
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
IZZI
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
GALE WARNING...LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-LMZ868-
LMZ870-LMZ872-LMZ874 UNTIL 9 AM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
WWW.YOUTUBE.COM/NWSCHICAGO
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
727 AM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 549 AM EDT SUN MAY 12 2013
UPPER PATTERN FEATURING WESTERN CONUS RIDGING AND EASTERN CONUS
TROUGHING BECOMES MORE ZONAL THROUGH THE WEEK...RESULTING IN
WARMING TREND FOR UPPER GREAT LAKES. AS THE UPPER PATTERN BECOMES
MORE ZONAL EXPECT SFC LOW AND FRONTAL BOUNDARIES TO MOVE FROM
CENTRAL CANADA ACROSS THE GREAT LAKES TUESDAY THROUGH THURSDAY. BEST
CHANCE OF RAIN IN THIS PATTERN SHOULD BE LATER TUESDAY THROUGH
TUESDAY NIGHT AS WARM FRONT SLIDES ACROSS UPPER GREAT LAKES. EXTENT
OF COOLING BEHIND COLD FRONT WEDNESDAY INTO THURSDAY UNCERTAIN. EVEN
THE MODELS THAT ARE SHOWING THE MOST EMPHATIC COOLING /GFS AND NAM/
SHOW NOTHING TO THE EXTENT OF CURRENT COOLDOWN THAT IS CURRENTLY
OCCURRING. SO...BEYOND THIS TASTE OF WINTER AFFECTING THE REGION
THIS MORNING...EXPECT EXTENDED TO HOLD ONLY LIQUID PRECIPITATION.
HIGH PRESSURE BEGINS THE EXTENDED PERIOD OVER WESTERN GREAT LAKES.
RIDGE AXIS HEADS ACROSS REST OF GREAT LAKES BY MONDAY NIGHT ALLOWING
WARM AIR ADVECTION/RETURN FLOW TO DEVELOP. THROUGH DAY 2 LEANED ON
THE NAM/GFS SOUNDINGS TO TRY TO GAGE PRECIP CHANCES. MOISTURE
ADVECTION FOCUSED MAINLY ALOFT H85-H7 MONDAY NIGHT. SOME LGT SHOWERS
SEEM LIKELY IN MAX ADVECTION AREA MOVING WEST TO EAST ACROSS CWA.
ONCE MID-LEVEL MOISTURE/LIFT IS STRIPPED AWAY...SHALLOW MOISTURE
MAINLY BLO H9 IS ALL THAT IS LEFT ON TUESDAY. HINTS FROM MODELS THAT
MOISTURE MAY MIX OUT BY AFTN. LOWERED POPS BASED ON LIMITED MOISTURE
INTO TUESDAY AFTN. NEXT SURGE OF MOISTURE/TEMPERATURE ADVECTION AND
ELEVATED INSTABILITY COULD BRING SHOWERS/TSRA OVER GENERALLY WESTERN
CWA LATE TUESDAY AFTN. SE WINDS AHEAD OF WARM FRONT WITH MORE
INFLUENCE OFF LK MICHIGAN FOR MUCH OF CWA SHOULD KEEP TEMPS FROM
GETTING TOO WARM EVEN WITH ONLY SCT CLOUDS BY AFTN. WARMEST READINGS
INTO THE 70S INLAND WEST AND SOUTHWEST CWA WITH LESS LAKE MODIFIED
COOLER AIR. UPR 50S TO UPR 60S ELSEWHERE.
WARM FRONT PASSAGE/MAXIMUM LOW-LEVEL MOISTURE AND TEMP ADVECTION
STILL ON TRACK FOR TUESDAY NIGHT. HAS LOOKED THIS WAY FOR A WHILE
NOW. STILL THINKING THIS IS THE BEST CHANCE FOR SHOWERS AND TSRA
ACROSS CWA...BUT STILL MAY NOT BE WIDESPREAD EVENT FOR ALL CWA. SOME
DIFFERENCE HOW FAR SOUTH SHORTWAVE TROUGH/MID-LEVEL HEIGHT FALLS DIP
INTO UPR LAKES AND THIS IMPACTS SOUTHERN EXTENT OF PRIMARY UPPER
LEVEL JET AND ASSOCIATED DIVERGENCE TO ENHANCE PRECIP. PLACED LIKELY
POPS OVER NORTH AND EAST AND KEPT POPS SCATTERED FARTHER SOUTH. GIVEN
H85 DWPNTS OVER +12C AND 1-6KM MUCAPES OVER 1000J/KG AND SINCE AXIS
OF 925-850MB WIND MAX IS OVERHEAD...SHRA AND TSRA CANNOT BE COUNTED
OUT ANYWHERE THOUGH. STRONGST WINDS ALOFT ARE MORE OVER LAKE SUPERIOR
AND NORTH INTO ONTARIO SO THINK THIS IS WHERE BETTER CHANCE OF
STRONGER STORMS WOULD BE LOCATED. SEEMS THAT LIGHTNING AND HEAVY
DOWNPOURS WILL BE THE PRIMARY HAZARDS. THOUGH WBZERO HEIGHTS
11-12KFT IS ON THE HIGHER SIDE TO SEE LARGE HAIL...IT IS POSSIBLE
GIVEN STRONGER SHEAR AND H7-H5 LAPSE RATES OVER 7C/KM.
GOOD AGREEMENT THAT AREA OF ENHANCED PRECIP SWIFTLY CROSSES THE AREA
LATER TUESDAY NIGHT WITH COLD FRONTAL PASSAGE NOT TOO FAR BEHIND ON
WEDNESDAY MORNING. SUBSTANTIAL CLEARING IN THE OFFING ON WEDNESDAY
IN WAKE OF THE FRONT. 00Z ECMWF TRENDED SLIGHTLY TOWARD COLDER GFS
IDEA FOR H85 TEMPS IN WAKE OF COLD FRONT...BUT EVEN SO...EXPECT
SUNSHINE AND DEEP MIXING TO OFFSET THIS AND LEAD TO MAX TEMPS INTO
THE 70S SOUTHWEST AND SOUTH CENTRAL. READINGS IN THE 60S CLOSER TO
LK SUPERIOR. WINDS MAY END UP STRONGER THAN WHAT CONSENSUS SHOWED
BUT LEFT THEM ALONE FOR NOW. DID GO WITH LOWER BIAS CORRECTED MOS
DWPNTS IN THE AFTN GIVEN THE DEEP MIXING.
THURSDAY AND FRIDAY....A BIT UNSETTLED POTENTIALLY. PRIMARY SFC
FRONTAL BOUNDARY WILL REMAIN SOUTH OF UPR MICHIGAN. YET SINCE THE
AREA IS ON SOUTHERN EDGE OF TROUGH OVR CANADA...THE JET STREAM IS
TOO CLOSE BY TO NOT HAVE AT LEAST SLIGHT CHANCE POPS. MODELS HAVE
SHOWN SOME QPF FROM TIME TO TIME...ESPECIALLY LATER FRIDAY AND
FRIDAY NIGHT AS SECONDARY SFC TROUGH DIPS SOUTH ACROSS THE UPPER
GREAT LAKES.
BY NEXT WEEKEND THE MAIN ISSUE WILL BE INFLUENCE OF DEVELOPING LOW
PRESSURE OVER PLAINS. 12Z ECMWF FARTHER TO THE EAST...WHILE GFS AND
WPC HAND DRAWN PROGS KEEP LOW SHUNTED MORE OVER THE PLAINS AND SFC
RIDGE OVER THE UPR LAKES. CONSENSUS OF MODELS WHICH HAS DOUBLE
WEIGHTING OF THE TYPICALLY BETTER PERFORMING ECMWF SHOWS INCREASING
CHANCES OF SHOWERS BY LATER IN THE WEEKEND. TEMPS TO END THE
EXTENDED WILL BE AROUND NORMAL...THOUGH MAY REMAIN SLIGHTLY BELOW
NORMAL ALONG LK SUPERIOR DUE TO PREVAILING NORTHERLY SFC WINDS.
EVEN IF IT DOES END UP BELOW NORMAL...NO SNOW IS IN THE
FORECAST...WHICH IS CERTAINLY WELCOME NEWS FOR THOSE WEARY OF THE
WINTER THAT HAS BEEN RELUCTANT TO END.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 721 AM EDT SUN MAY 12 2013
MVFR CONDITIONS WILL GRADUALLY IMPROVE TO VFR AT KCMX AND KSAW WITH
ADVECTION OF DRIER AIR FROM THE WEST AND WEAK DIURNAL HEATING. KIWD
SHOULD SEE VFR STRATOCU DECK SCT OUT BY LATE MORNING AS DRIER DRY
AIR WORKS IN FM WEST. NW WINDS WILL BE GUSTY TO AROUND 25 KT AT KCMX
AND KSAW THROUGH AT LEAST MID AFTERNOON. LOOK FOR WINDS TO DIE OFF
THIS EVENING.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LSZ248.
LAKE MICHIGAN...
GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LMZ250.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS HASTINGS NE
820 AM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 820 AM CDT SUN MAY 12 2013
LIGHT SHOWERS CONTINUE TO SLIDE THROUGH PORTIONS OF THE REGION
THIS MORNING. A FEW LIGHTNING STRIKES HAVE BEEN REPORTED WITH
THESE SHOWERS. THEREFORE WENT AHEAD AND ADDED ISOLATED THUNDER TO
THE FORECAST THIS MORNING.
UPDATE ISSUED AT 543 AM CDT SUN MAY 12 2013
HAVE BEEN WATCHING TEMPERATURES WARM PRIOR TO DAWN AS THE CLOUDS
HAVE MOVED IN. THIS WAS PRETTY MUCH EXPECTED THAT WE WOULD WARM
ONCE THE CLOUDS MOVED IN THIS MORNING. THUS WE HAVE EXPIRED THE
FROST ADVISORY ACROSS NORTHWEST ZONES WHERE TEMPERATURES HAVE NOW
RISEN FROM THE LOWER AND MID 30S INTO THE MID AND UPPER 30S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS. INSTABILITY
WILL BUILD A LITTLE MORE EACH DAY.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
IF WE DO GET AN MCS THRU HERE IT COULD SERIOUSLY IMPACT OUR TEMPS
THE FOLLOWING DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 543 AM CDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF VALID PERIOD. THE WIND
WILL REMAIN OUT OF THE SOUTHEAST. THERE ARE A FEW ISOLATED
SPRINKLES AROUND THE AREA THIS MORNING BUT THESE WILL BE HIT AND
MISS AND QUICKLY OUT OF THE AREA BY MID MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...SALTZMAN
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS HASTINGS NE
556 AM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 543 AM CDT SUN MAY 12 2013
HAVE BEEN WATCHING TEMPERATURES WARM PRIOR TO DAWN AS THE CLOUDS
HAVE MOVED IN. THIS WAS PRETTY MUCH EXPECTED THAT WE WOULD WARM
ONCE THE CLOUDS MOVED IN THIS MORNING. THUS WE HAVE EXPIRED THE
FROST ADVISORY ACROSS NORTHWEST ZONES WHERE TEMPERATURES HAVE NOW
RISEN FROM THE LOWER AND MID 30S INTO THE MID AND UPPER 30S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS. INSTABILITY
WILL BUILD A LITTLE MORE EACH DAY.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
IF WE DO GET AN MCS THRU HERE IT COULD SERIOUSLY IMPACT OUR TEMPS
THE FOLLOWING DAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 543 AM CDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF VALID PERIOD. THE WIND
WILL REMAIN OUT OF THE SOUTHEAST. THERE ARE A FEW ISOLATED
SPRINKLES AROUND THE AREA THIS MORNING BUT THESE WILL BE HIT AND
MISS AND QUICKLY OUT OF THE AREA BY MID MORNING.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...WESELY
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...WESELY
AREA FORECAST DISCUSSION
NWS PORTLAND OR
855 AM PDT SUN MAY 12 2013
.SYNOPSIS...A FRONTAL SYSTEM NEAR THE COAST WILL WEAKEN AND DISSIPATE
AS IT MOVES ACROSS THE AREA TODAY. THE BULK OF THE RAINFALL WITH THIS
SYSTEM WILL REMAIN WELL TO THE NORTH...BUT WILL LIKELY CONTINUE TO
SEE SOME LIGHT PRECIP IN OUR NORTHERN ZONES TODAY. A REINFORCING
UPPER LEVEL SHORTWAVE WILL BRING MORE WIDESPREAD AND HEAVIER RAIN TO
THE REGION MONDAY. A FEW THUNDERSTORMS MAY DEVELOP ACROSS THE
NORTHERN ZONES ON MONDAY AS WELL. SEVERAL WEAK STORM SYSTEMS WILL
SKIRT THE REGION NEXT WEEK BRINGING CLOUDS...PERIODIC SHOWER
ACTIVITY AND TEMPERATURES NEAR SEASONAL NORMALS.
&&
.SHORT TERM...THE STRONG RIDGE OF HIGH PRESSURE THAT DOMINATED THE
WEATHER OVER THE PACNW FOR THE PAST SEVERAL DAYS HAS MOVED EASTWARD.
NEAR THE COAST...A FRONTAL SYSTEM WILL WEAKEN AND DISSIPATE AS IT
PUSHES INLAND TODAY. MOST OF THE ENERGY AND HEAVIER PRECIP WITH THIS
FRONT CONTINUES TO BE AIMED WELL TO THE NORTH TOWARD BC AND THE
OLYMPIC PENINSULA. THE HRRR MODEL SHOWS THE FRONT DISSIPATING AS IT
MOVES OVER THE COAST RANGE...WITH ANY SIGNIFICANT PRECIP MAINLY
AFFECTING THE NORTH COAST AND THE SOUTH WA AND NORTH OR CASCADES AND
FOOTHILLS. GIVEN THE RECENT WARM AIRMASS THERE MAY BE ENOUGH ENERGY
TO ENHANCE SHOWER ACTIVITY THIS AFTERNOON ACROSS THE INTERIOR AS WHAT
REMAINS OF THE FRONT MOVES THROUGH.
A MORE POTENT SHORTWAVE WILL MOVE INTO THE REGION ON MONDAY. THIS
SYSTEM WILL DROP FURTHER SOUTH...WITH THE BASE OF THE TROUGH MOVING
THROUGH OREGON. THIS TRACK WOULD RESULT IN SIGNIFICANTLY MORE FORCING
OVER SW WASHINGTON AND NW OREGON WITH INCREASED WESTERLY OROGRAPHIC
FLOW. SO...MONDAY APPEARS TO HOLD A MUCH BETTER SHOT FOR RECEIVING
SOME DECENT RAINFALL ACROSS OUR DISTRICT. MODELS ALSO SHOW QUITE
A BIT OF INSTABILITY FROM ABOUT SALEM NORTHWARD ON MONDAY
AFTERNOON...SO THERE IS ALSO A THREAT OF THUNDERSTORM ACTIVITY
MONDAY AFTERNOON INTO THE EARLY EVENING HOURS.
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
TUE THROUGH FRIDAY...AFTER THE SYSTEM ON MON PASSES THROUGH...THE PAC
NW WILL BE LEFT IN A RELATIVELY ZONAL PATTERN FOR THE REST OF THE
WEEK. A COUPLE OF WEAK TROUGHS ARE DEPICTED MOVING THROUGH THE UPPER
FLOW...SO WE WILL HAVE THE POTENTIAL FOR SOME SOME PERIODIC SHOWER
ACTIVITY. HOWEVER...NOTHING VERY WELL ORGANIZED IS EXPECTED.
OTHERWISE...EXPECT CLOUDS AND COOLER MORE SEASONAL TEMPS FOR NEXT
WEEK. PYLE
&&
.AVIATION...A COLD FRONT IS SLOWLY PUSHING ONSHORE THIS MORNING.
EXPECT LIGHT SHOWERS AND PERIODS OF MVFR CIGS AS THE FRONT SLOWLY
MOVES THROUGH...ESPECIALLY THROUGH ABOUT 20Z. CHANCES FOR MORE
WIDESPREAD MVFR INCREASE THIS EVENING AS THE WINDS TURN MORE
SOUTHWESTERLY. A STRONGER FRONT WILL MOVE IN OVERNIGHT INTO
MON...BRINGING HEAVIER RAIN AND LOWERED CIGS.
KPDX AND APPROACHES...EXPECT PERIODIC LIGHT RAIN AND MVFR CIGS
TODAY AS A WEAK FRONT SLOWLY PUSHES THROUGH. A STRONGER FRONT WILL
BRING HEAVIER RAIN AND PREDOMINANTLY MVFR CIGS BETWEEN 12Z AND 18Z
TOMORROW MORNING. PYLE
&&
.MARINE...A WEAK COLD FRONT IS PUSHING INLAND THIS MORNING. WINDS
ARE RUNNING LOWER THAN THE MODELS ARE SUGGESTING...SO DECIDED TO
END THE SMALL CRAFT ADVISORY FOR WINDS THIS MORNING. A STRONGER
WAVE WILL MOVE ALONG THE FRONTAL BOUNDARY ON TOMORROW MORNING AND
MON...WHICH SHOULD BRING A MORE SOLID SMALL CRAFT ADVISORY EVENT.
SEAS SHOULD REMAIN 4 TO 6 FT RANGE TODAY THEN INCREASE FURTHER
WITH THE SYSTEM ON MON...POTENTIALLY REACHING NEAR 10 FT LATE MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...NONE.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS PORTLAND OR
310 AM PDT SUN MAY 12 2013
.SYNOPSIS...A FRONTAL SYSTEM NEAR THE COAST WILL WEAKEN AND DISSIPATE
AS MOVES ACROSS THE AREA TODAY. THE BULK OF THE RAINFALL WITH THIS
SYSTEM WILL REMAIN WELL TO THE NORTH...BUT WILL LIKELY SEE SOME LIGHT
PRECIP IN OUR NORTHERN ZONES TODAY. A REINFORCING UPPER LEVEL
SHORTWAVE WILL BRING MORE WIDESPREAD AND HEAVIER RAIN TO THE REGION
MONDAY. A FEW THUNDERSTORMS MAY DEVELOP ACROSS THE NORTHERN ZONES ON
MONDAY AS WELL. SEVERAL WEAK STORM SYSTEMS WILL SKIRT THE REGION NEXT
WEEK BRINGING CLOUDS...PERIODIC SHOWER ACTIVITY AND TEMPERATURES NEAR
SEASONAL NORMALS.
&&
.SHORT TERM...THE STRONG RIDGE OF HIGH PRESSURE THAT DOMINATED THE
WEATHER OVER THE PACNW FOR THE PAST SEVERAL DAYS HAS MOVED EASTWARD.
NEAR THE COAST...A FRONTAL SYSTEM WILL WEAKEN AND DISSIPATE AS IT
PUSHES INLAND TODAY. MOST OF THE ENERGY AND HEAVIER PRECIP WITH THIS
FRONT CONTINUES TO BE AIMED WELL TO THE NORTH TOWARD BC AND THE
OLYMPIC PENINSULA. THE HRRR MODEL SHOWS THE FRONT DISSIPATING AS IT
MOVES OVER THE COAST RANGE...WITH ANY SIGNIFICANT PRECIP MAINLY
AFFECTING THE NORTH COAST AND THE SOUTH WA AND NORTH OR CASCADES AND
FOOTHILLS.
A MORE POTENT SHORTWAVE WILL MOVE INTO THE REGION ON MONDAY. THIS
SYSTEM WILL DROP FURTHER SOUTH...WITH THE BASE OF THE TROUGH MOVING
THROUGH OREGON. THIS TRACK WOULD RESULT IN SIGNIFICANTLY MORE FORCING
OVER SW WASHINGTON AND NW OREGON WITH INCREASED WESTERLY OROGRAPHIC
FLOW. SO...MONDAY APPEARS TO HOLD A MUCH BETTER SHOT FOR RECEIVING
SOME DECENT RAINFALL ACROSS OUR DISTRICT. MODELS ALSO SHOW QUITE
ABIT OF INSTABILITY FROM ABOUT SALEM NORTHWARD ON MONDAY
AFTERNOON...SO THERE IS ALSO A THREAT OF THUNDERSTORM ACTIVITY
MONDAY AFTERNOON INTO THE EARLY EVENING HOURS. TW
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...
TUE THROUGH FRIDAY...AFTER THE SYSTEM ON MON PASSES THROUGH...THE PAC
NW WILL BE LEFT IN A RELATIVELY ZONAL PATTERN FOR THE REST OF THE
WEEK. A COUPLE OF WEAK TROUGHS ARE DEPICTED MOVING THROUGH THE UPPER
FLOW...SO WE WILL HAVE THE POTENTIAL FOR SOME SOME PERIODIC SHOWER
ACTIVITY. HOWEVER...NOTHING VERY WELL ORGANIZED IS EXPECTED.
OTHERWISE...EXPECT CLOUDS AND COOLER MORE SEASONAL TEMPS FOR NEXT
WEEK. PYLE
&&
.AVIATION...A COLD FRONT IS STALLED OFFSHORE THROUGH TONIGHT.
EXPECT SOME LIGHT RAIN AT TIMES ON THE COAST AND FAR NW OREGON AND
SW WASHINGTON. ON THE COAST...GENERALLY VFR CONDITIONS THIS
MORNING WITH OCCASIONAL MVFR CONDITIONS ESPECIALLY NORTH. CHANCES
FOR MORE WIDESPREAD MVFR INCREASE IN THE AFTERNOON AS THE WINDS
TURN MORE SOUTHWESTERLY. INLAND AREAS ARE EXPECTED TO REMAIN VFR
TODAY WITH MVFR CIGS POSSIBLE LATER TONIGHT.
KPDX AND APPROACHES...VFR EXPECTED THROUGH 06Z MON. AFTER THAT
MODELS ARE INDICATING INCREASING CHANCES FOR MVFR CIGS AROUND
2500-3000 FEET. BUT CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE MVFR
CONDITIONS IN THE 12Z TAFS.
&&
.MARINE...FRONT REMAINS OFFSHORE WITH SLOW EASTWARD PROGRESS AS
SEVERAL WAVES RIDE ALONG THE FRONT. MAIN CHANGES FOR TODAY IS TO
ADJUST TIMING OF THE MARGINAL SMALL CRAFT ADVISORY FOR THE
NORTHERN OUTER WATERS TO 5 AM TO 11 AM TODAY. A STRONGER WAVE WILL
MOVE ALONG THE FRONTAL BOUNDARY ON MON AND WILL PROBABLY BRING A
MORE SOLID SMALL CRAFT ADVISORY EVENT.
SEAS SHOULD REMAIN 4 TO 6 FT RANGE TODAY THEN INCREASE FURTHER
WITH THE SYSTEM ON MON...POTENTIALLY REACHING NEAR 10 FT LATE MON.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS FROM 5 AM TO 11 AM PDT THIS
MORNING FOR WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD
OR FROM 10 TO 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR FROM 5 AM
TO 9 AM PDT THIS MORNING.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1100 AM CDT SUN MAY 12 2013
.UPDATE...NO CHANGE TO FROST/FREEZE HEADLINES FOR TONIGHT.
PC
&&
.AVIATION/18Z TAFS/...VERY COLD AND BROAD UPPER TROUGH CONTINUES
ACROSS THE UPPER MIDWEST. -34C 500 MILLIBAR TEMP AT KGRB FROM 12Z
RESULTING IN VFR VFR CU FIELD AFFECTING ERN HALF OF WI. SKIES
WILL BE CLEAR TONIGHT. WINDS DIMINISH AS WELL WITH SURFACE RIDGE
AXIS SLIDING ACROSS. MID DECK WILL INCREASE MONDAY AFTERNOON WITH
700 MILLIBAR WARM ADVECTION. BEST POTENTIAL FOR SHRA WILL BE IN SC
WI LATER IN THE AFTERNOON.
PC
&&
.PREV DISCUSSION... /ISSUED 345 AM CDT SUN MAY 12 2013/
TODAY...FORECAST CONFIDENCE...MEDIUM TO HIGH
NOT AS MUCH INSTABILITY OR DYNAMIC PUNCH AS THERE WAS
YESTERDAY...BUT STILL HAVE THE THE WESTERN EDGE OF THE COLD POOL
OVER US...ESPECIALLY OVER THE EASTERN CWA THIS MORNING. SHOULD SEE
CU POP BY MID MORNING. RAP SOUNDINGS SHOW A DEEPER CLOUD LAYER
THAN NAM OR GFS...WITH SOME MINIMAL CAPE DEVELOPING SOME SPRINKLES
IN THE SOUTHEAST IN THE AFTERNOON. WILL LEAVE OUT FOR NOW...BUT
WILL NEED TO BE WATCHED WITH SHEARED VORT DROPPING THROUGH REGION
THIS AFTERNOON PROVIDING A BIT OF EXTRA LIFT. THE COLD AIR
ADVECTION HAS BROUGHT 925 MB TEMPERATURES DOWN TO -1C TO -4C...BUT
MODELS AGREE THAT THEY WILL RECOVER TO +3 TO +5C BY 00Z. THOUGH
WARMEST 925 MB TEMPS WILL ARRIVE TOWARD THE END OF THE
DAY...ENOUGH OF AN INFLUENCE TO LEAN TOWARD WARMER GUIDANCE WITH
MID 50S IN THE WEST...TO AROUND 50 IN THE FAR EAST.
TONIGHT...FORECAST CONFIDENCE...HIGH
GIVEN THE EXPECTED GOOD RADIATIONAL COOLING CONDITIONS AS SURFACE
RIDGE AXIS MOVES OVER THE STATE TONIGHT ...AND WITH BUFKIT SOUNDINGS
SUPPORTING THE THE NAM/GFS 2-METER TEMPERATURES AND MOS GUIDANCE...
WILL ISSUE A FREEZE WARNING FOR THE FAR NW COUNTIES WHERE LOWS TO
BOTTOM OUT IN THE UPPER 20S...AND A FROST ADVISORY FOR THE REST OF
THE CWA WITH LOW 30S AWAY FROM THE IMMEDIATE LAKESHORE. EVEN
MILWAUKEE AND OZAUKEE COUNTIES SHOULD SEE AREAS OF FROST IN THEIR
FAR WEST. THE LOWEST TEMPERATURES ARE CURRENTLY LIMITED TO NORTHERN
SECTIONS OF THE FREEZE WARNING COUNTIES...BUT WARNING WOULD HAVE TO
BE EXPANDED IF THE COLDER NAM IS CORRECT.
MONDAY THROUGH WEDNESDAY...FORECAST CONFIDENCE...MEDIUM
THE AXIS OF SURFACE HIGH PRESSURE WILL BE OVERHEAD MONDAY
MORNING...SO THERE SHOULD BE PLENTY OF SUNSHINE TO START THE DAY.
THE HIGH WILL SLIDE EAST DURING THE DAY...WITH STRONG WARM ADVECTION
ALOFT SLIDING INTO THE WEST BY LATE AFTERNOON. THIS WILL BRING
INCREASING CLOUDS ALONG WITH A CHANCE FOR SHOWERS TO MAINLY WESTERN
PORTIONS OF THE FORECAST AREA.
THE MAX OF THE WARM ADVECTION WILL SLIDE THROUGH MAINLY DURING THE
EVENING HOURS...SO KEPT HIGHEST POPS DURING THAT PERIOD. SHOULD BE
MAINLY DRY THEN TUESDAY AS A WARMER AND CAPPED AIRMASS MOVES INTO
THE FORECAST AREA.
THE SURFACE COLD FRONT IS EXPECTED TO DROP THROUGH SOUTHERN
WISCONSIN TUESDAY EVENING AND OVERNIGHT. MODELS ARE NOT SHOWING MUCH
LIFT WITH THIS FRONT...SO KEPT POPS ON THE LOW END.
TEMPERATURES MONDAY WILL CLIMB BACK TOWARD NORMAL VALUES UNDER
SOUTHERLY WINDS BEHIND THE EXITING HIGH PRESSURE. MUCH WARMER
TEMPERATURES ARE THEN EXPECTED TUESDAY...WITH HIGH TEMPERATURES
EXPECTED TO CLIMB WELL ABOVE NORMAL INTO THE 80S ACROSS THE WESTERN
FORECAST AREA. THERE IS MUCH LESS CERTAINTY WITH TEMPERATURES IN THE
EAST THOUGH. MODELS VARY A BIT ON THE TIMING OF THE SYSTEM...THUS
IMPACTING WIND DIRECTION. IF THE WINDS STAY SOUTHEAST THROUGH THE
DAY AS THE SLOWER ECMWF SUGGESTS...HIGH TEMPS WILL LIKELY BE COOLER
THAN WHAT IS CURRENTLY FORECAST. THE QUICKER NAM AND CANADIAN WOULD
HAVE SOUTHWEST WINDS FOR A GOOD PART OF THE DAY...RESULTING IN
WARMER TEMPS THAN FORECAST. OPTED TO GO DOWN THE MIDDLE FOR TEMPS
TOWARD THE LAKE FOR NOW UNTIL MODELS COME INTO BETTER AGREEMENT.
THOUGH THE SURFACE FRONT WILL LIKELY HAVE PUSHED SOUTH BY WEDNESDAY
MORNING...MODELS ARE STILL SHOWING A FAIR AMOUNT OF WARM AIR
LINGERING ACROSS SOUTHERN WISCONSIN. HIGH TEMPS ARE THUS EXPECTED TO
REMAIN ABOVE NORMAL.
THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE...LOW TO MEDIUM
HAVE SHOWER AND STORM CHANCES THROUGH THE LATTER HALF OF THE WEEK AS
MODELS CONTINUE TO SHOW THE FRONTAL BOUNDARY STALLING IN THE AREA.
WILL LIKELY SEE SYSTEMS MOVE THROUGH ALONG THE BOUNDARY. BIGGEST
ISSUE IS HOW FAR SOUTH THE BOUNDARY WILL STALL AND THEN TIMING OF
THE INDIVIDUAL SYSTEMS AND RESULTANT PRECIP CHANCES.
ALSO...DIFFERING PLACEMENTS OF THE STALLED FRONT ARE PRODUCING
DECENT SPREADS IN TEMPS AMONG MODELS. NOT A HIGH CONFIDENCE
SETUP...SO STUCK WITH A CONSENSUS APPROACH FOR TEMPERATURES.
AVIATION/12Z TAFS/...
SHOULD SEE VFR CU DEVELOP/4-5K FT/ BY MID-MORNING AND BECOME BROKEN.
WINDS WILL BE GUSTY TO START AFTER MORNING MIX OUT...THEN SLOWLY
SUBSIDE THROUGH THE AFTERNOON AND REALLY EASE THIS EVENING AS
SURFACE RIDGE BUILDS INTO THE AREA. VFR FOR REMAINDER OF THE PERIOD
WITH LIGHT WINDS AND CLEAR SKIES TONIGHT.
MARINE...
CURRENT FORECAST WIND GUSTS STILL INDICATE 3 PM CDT END TIME FOR
SMALL CRAFT ADVISORY HOLDS...THOUGH THERE COULD BE A FEW CRITERIA
GUSTS UNTIL AFTER SUNSET...ESPECIALLY IN THE NORTHERN ZONES. WINDS
WILL EASE TONIGHT AS SURFACE RIDGE PASSES THROUGH...TURNING SOUTH
MONDAY AFTERNOON AND INCREASING MONDAY NIGHT AHEAD OF NEXT LOW.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ051-052-
057>060-062>072.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ046-047-056.
LM...SMALL CRAFT ADVISORY UNTIL 3 PM CDT THIS AFTERNOON FOR
LMZ643>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...REM
MONDAY THROUGH SATURDAY...DDV
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
611 AM CDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MAIN FORECAST CONCERN IS ON FROST/FREEZE CONDITIONS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO ALBERTA WHILE ANOMALOUSLY
DEEP TROUGHING WAS PRESENT FROM HUDSON BAY INTO THE WESTERN GREAT
LAKES REGION. THE FORECAST AREA LIES ON THE BACK SIDE OF THE
TROUGHING...BUT STILL EAST OF THE INFLECTION POINT...WHICH RESULTS
IN NORTHWEST FLOW FROM THE SURFACE TO 500MB. THE FLOW CONTINUED TO
DRAG COLDER AIR SOUTHEAST WITH RAP 850MB TEMPS RANGING FROM -3C OVER
NORTHEAST IOWA TO -9C IN TAYLOR COUNTY WISCONSIN. DESPITE THE COLD
850MB TEMPS...READINGS ARE GENERALLY IN THE MID 30S TO AROUND 40...
STAYING UP BECAUSE OF THAT NORTHWEST WIND OF 5-10 KT AT THE SURFACE
KEEPING THE BOUNDARY LAYER MIXED. A LOT OF DRY AIR CONTINUES TO FLOW
IN TOO ON THE NORTHWEST WINDS FROM HIGH PRESSURE IN THE PLAINS.
DEWPOINTS ARE IN THE TEENS ACROSS MUCH OF THE DAKOTAS INTO MN AND
20S OVER WISCONSIN. COMBINATION OF THE WIND...TEMPERATURES AND DRY
AIR PRECLUDING ANY FROST DEVELOPMENT THUS FAR. THE AFOREMENTIONED
DRY AIR IS ALSO QUITE DEEP...REFLECTIVE FROM 00Z SOUNDINGS AT BIS...
ABR AND MPX HAVING PRECIPITABLE WATER VALUES OF 0.1-0.2 INCHES...OR
20-40 PERCENT OF NORMAL. THIS DRY AIR HAS HELPED CLEAR SKIES OUT
WEST OF WISCONSIN. SCT-BKN CLOUDS HAVE BEEN FLOWING ACROSS WISCONSIN
IN THE CYCLONIC FLOW IN THE UPPER TROUGH. FARTHER TO THE WEST UNDER
THE UPPER RIDGE...00Z SOUNDINGS FROM SAN FRANSISCO TO SALT LAKE CITY
AND NORTH TO GREAT FALLS MT ALL REPORTED 850MB TEMPS OF 20C OR
GREATER. THESE ARE 1.5-2.5 STANDARD DEVIATIONS ABOVE NORMAL.
BOTH THE UPPER RIDGE AND ANOMALOUSLY DEEP TROUGH ARE PROGGED TO
PROGRESS EASTWARD DURING THE NEXT 24 HOURS...PUSHED ALONG BY A
FAIRLY POTENT SHORTWAVE TROUGH APPROACHING THE PACIFIC NORTHWEST
COAST AT 12Z MONDAY. IT APPEARS THIS EVENING IS WHEN THE INFLECTION
POINT BETWEEN THE UPPER RIDGE AND DEEP TROUGH WILL REACH THE
FORECAST AREA. THIS MEANS TO PLAN ON THE SURFACE HIGH OVERHEAD AT
ABOUT THE SAME TIME.
TODAY...THE COMBINATION OF DRY AIR AND BEING FARTHER AWAY FROM THE
COLD POOL OF THE UPPER TROUGH WILL RESULT IN SUNNY SKIES. SINCE THE
AREA STAYS IN A GRADIENT AHEAD OF THE SURFACE HIGH AND WE HAVE FULL
SUN FOR DEEP MIXING...ANOTHER BREEZY DAY IS LIKELY...BUT NOT NEARLY
AS WINDY AS YESTERDAY. TEMPERATURES ARE DEFINITELY GOING TO STAY ON
THE COOL SIDE...THOUGH...WITH 850MB TEMPS HOLDING STEADY THROUGH
18Z. HIGHS SHOULD END UP VERY SIMILAR TO YESTERDAY.
TONIGHT...A REALLY GOOD RADIATIONAL COOLING SETUP IS FORECAST. WITH
THE SURFACE HIGH MOVING OVER THE AREA DURING THE EVENING...WINDS
WILL DECOUPLE EVERYWHERE. ADDITIONALLY...WE HAVE ALL OF THE DRY AIR
ACCOMPANYING THE SURFACE HIGH. THUS...TEMPERATURES SHOULD PLUMMET
DURING THE EVENING HOURS AFTER SUNSET. NOW...AFTER MIDNIGHT...THE
SURFACE RIDGE BEGINS TO PUSH EAST INTO CENTRAL WISCONSIN. THIS MEANS
A SOUTHERLY WARM ADVECTION FLOW WILL COMMENCE OVER WESTERN PORTIONS
OF THE FORECAST AREA. THEREFORE...OUR WISCONSIN COUNTIES CONTINUE TO
LOOK THE MOST FAVORABLE FOR THE COLDEST CONDITIONS...AND THE COLDEST
OVERALL OVER CENTRAL WISCONSIN. STAYED TOWARDS THE COLD SIDE OF
GUIDANCE FOR LOWS. GIVEN THE CONSISTENCY FOR TONIGHT TO BE COLD...
HAVE ISSUED FREEZE WARNINGS FOR THE PREVIOUS FREEZE WATCH AREA AND A
FEW EXTRA COUNTIES WHERE TEMPS ARE NOW FORECAST COLDER...WITH FROST
ADVISORIES FOR THE REST OF OUR WISCONSIN COUNTIES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING OVER THE WESTERN
U.S. IS PROGGED TO CONTINUE TO GET PUSHED EASTWARD WHILE FLATTENING
WITH TIME. THIS IN RESPONSE TO THE POTENT SHORTWAVE OFF THE PACIFIC
NORTHWEST AT 12Z MONDAY TRACKING EASTWARD ALONG THE U.S./CANADIAN
BORDER. OVERALL MODELS ARE IN PRETTY GOOD AGREEMENT ON THE TRACK AND
SPEED OF THIS SHORTWAVE...WITH THE EXCEPTION OF THE 12.00Z NAM
WHICH BECOMES SLIGHTLY FASTER COME TUESDAY AND TUESDAY NIGHT. HAVE
DISCOUNTED THE NAM PROGRESSION AS AN OUTLIER FOR NOW. THE
PROGRESSIVE NATURE OF THE RIDGE AND SHORTWAVE RESULTS IN A VARIETY
OF ISSUES TO CONTEND WITH...
1. PRECIPITATION CHANCES AND TEMPERATURES MONDAY INTO MONDAY NIGHT.
A WARM FRONT AHEAD OF THE UPPER RIDGE AXIS IS FORECAST TO CROSS THE
AREA MONDAY NIGHT. PACIFIC MOISTURE MOVING THROUGH THE UPPER RIDGE
IN CONJUNCTION WITH ISENTROPIC LIFT AHEAD OF THIS WARM FRONT WILL
LIKELY TO LEAD TO EXTENSIVE MID AND HIGH CLOUDS. ADDITIONALLY...THE
LIFT APPEARS STRONG ENOUGH TO GENERATE PRECIPITATION FROM THESE
CLOUDS. THE BIG PROBLEM...THOUGH...IS LOW LEVEL DRY AIR LEFT OVER
FROM THE CURRENT CANADIAN HIGH PRESSURE AREA. OVERALL...12.00Z MODEL
GUIDANCE HAS BACKED OFF ON THE AMOUNT OF QPF POSSIBLE FROM THESE
CLOUDS...ESPECIALLY THE GFS...SUGGESTING THE DRY AIR MAY BE ABLE TO
ABSORB MUCH OF THE PRECIPITATION. HOWEVER...ALL GUIDANCE DOES
SUGGEST SOME LIGHT QPF POSSIBLE...THUS THE 20-40 PERCENT CHANCES
FROM THE PREVIOUS FORECAST STILL SEEMS REASONABLE. TIMING BETWEEN
18Z MONDAY TO 06Z TUESDAY ALSO STILL LOOKS GOOD. SHOULD SEE THE
CLOUDS AND PRECIPITATION PROGRESS EASTWARD THROUGH TIME DUE TO THE
PROGRESSION OF THE UPPER RIDGE. THE CLOUDS COMBINED WITH 850MB TEMPS
AT 18Z MONDAY OF 1C EAST TO 6C WEST ARE LIKELY TO KEEP TEMPERATURES
BELOW NORMAL...BUT NOT AS COLD AS TODAY.
2. HOW WARM TEMPERATURES WILL GET ON TUESDAY. THE SIGNAL OF A
CHINOOK WARM FRONT OFF THE ROCKIES...ACCOMPANYING THAT POTENT
SHORTWAVE...REMAINS FORECAST TO PUSH EAST THROUGH MUCH OF THE
FORECAST AREA DURING THE DAY TUESDAY. INCREDIBLY WARM 850MB TEMPS
FOR MID MAY ARE PROGGED TO FOLLOW IN ITS WAKE...WITH READINGS BY 00Z
OF 18-20C OVER CENTRAL WISCONSIN TO 22-24C WEST OF THE MISSISSIPPI
RIVER...OR 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. SEEING THE
OBSERVED 850MB TEMPS UNDER THE UPPER RIDGE RIGHT NOW OVER THE
WESTERN U.S...THESE SEEM REASONABLE. THE QUESTION IS WITH A WARM
ADVECTION PATTERN THROUGH THE DAY...CAN WE MIX TO THESE 850MB TEMPS.
MODELS CONTINUE TO BE NOTORIOUSLY HIGH WITH SURFACE DEWPOINTS IN
THIS SITUATION...PREVENTING MODELS FROM MIXING ENOUGH. FOR
EXAMPLE...THE 12.00Z GFS/ECMWF/CANADIAN JUMP THEM OVER IOWA FROM
50-55 AT 12Z TO 60-65 AT 18Z...ALL LIKELY DUE TO EVAPOTRANSPORATION
THAT IS NOT THERE YET. ADDITIONALLY...A DOWNSLOPE FLOW FROM THE
ROCKIES USUALLY ENDS UP WITH DRIER DEWPOINTS...ESPECIALLY THIS TIME
OF YEAR. THUS...HAVE CONTINUED TO STAY TOWARDS THE WARM SIDE OF
GUIDANCE. ALTHOUGH THE 12.00Z NAM IS SLIGHTLY TOO PROGRESSIVE...ITS
TEMPERATURES SEEM REASONABLE. FOLLOWED MOS GUIDANCE MORE FOR
DEWPOINTS SINCE MOS HAS BEEN DOING MUCH BETTER IN THIS DEPARTMENT.
3. COLD FRONT CROSSING TUESDAY NIGHT AND POTENTIAL FOR PRECIPITATION
WITH IT. 12.00Z NAM AND GFS ARE JUST SLIGHTLY FARTHER SOUTH WITH THE
TRACK OF THE SHORTWAVE TRACKING ALONG THE CANADIAN BORDER...COMPARED
TO THE 12.00Z ECMWF/UKMET/CANADIAN. THIS DIFFERENCE RESULTS IN THE
NAM/GFS ADDING EXTRA FORCING TO THE LOW LEVEL FRONTOGENESIS ZONE ON
AND BEHIND THE COLD FRONT...AND THUS THE MODELS PRODUCE A BAND OF
PRECIPITATION OVER THE AREA. THE ECMWF/UKMET/CANADIAN ARE DRY. FEEL
THE LATTER MODEL GROUP IS MORE LIKELY TO OCCUR...BUT CONTINUED TO
HONOR THE NAM/GFS SCENARIO WITH A 20 PERCENT CHANCE JUST IN CASE.
WEDNESDAY INTO NEXT WEEKEND...
GOOD MODEL AGREEMENT EXISTS OF THE FLOW STARTING OFF AS ZONAL TO
BEGIN THIS PERIOD. ANY LOW LEVEL FRONTOGENETICAL FORCING BEHIND
TUESDAY NIGHTS COLD FRONT IS SOUTH OF THE AREA FOR WEDNESDAY...SO
WENT DRY DURING THIS TIME. THE ZONAL FLOW DOES NOT LAST LONG...WITH
A NEW TROUGH PROGGED TO COME INTO THE PACIFIC NORTHWEST THURSDAY
NIGHT. THIS CAUSES THE FLOW DOWNSTREAM TO BUCKLE...WITH THE 12.00Z
ECMWF/GFS/CANADIAN ALL SHOWING A SHORTWAVE TROUGH TRACKING ACROSS MN
AND WI THURSDAY INTO THURSDAY NIGHT. HAVE HONORED THE SHORTWAVE WITH
SOME SMALL CHANCES OF PRECIPITATION. WE COULD END UP WITH A DRY DAY
FRIDAY WITH SUBSIDENCE AND HIGH PRESSURE BUILDING IN. LOWERED
PRECIPITATION CHANCES FURTHER AND MAY BE ABLE TO COMPLETELY PULL
THEM WITH THE NEXT EXTENDED FORECAST UPDATE. THINGS LOOK TO PERHAPS
TO GET MORE ACTIVE FOR FRIDAY NIGHT INTO THE WEEKEND AS THE PACIFIC
NORTHWEST TROUGH BEGINS TO APPROACH THE PLAINS. SURPRISINGLY GOOD
MODEL AGREEMENT BETWEEN THE ECMWF AND GFS...ALONG WITH PREVIOUS
RUNS...OF A DEEPENING LOW DOWNSTREAM OVER NEBRASKA. AS ONE WOULD
EXPECT...A SURGE OF MOISTURE TRANSPORT OUT OF THE GULF OF MEXICO IS
AIMED DIRECTLY TOWARDS THE FORECAST AREA AHEAD OF THE LOW.
THUS...PRECIPITATION CHANCES INCREASE...ESPECIALLY ON SATURDAY WHERE
THE CONSENSUS EVEN RESULTS IN 50-60 PROBABILITIES. TEMPERATURES
SHOULD SLOWLY COOL THROUGH THE EXTENDED...BUT STILL STAY AT OR ABOVE
NORMAL WITH A FLOW GENERALLY OFF THE PACIFIC.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 611 AM CDT SUN MAY 12 2013
PLAN ON VFR CONDITIONS AT KLSE/KRST TODAY THROUGH TONIGHT AS HIGH
PRESSURE BUILDS INTO THE AREA. LOOK FOR BREEZY NORTHWEST WINDS
TODAY IN THE 12-20KT RANGE...TAPERING OFF AFTER SUNSET.
&&
.FIRE WEATHER...TUESDAY
ISSUED AT 320 AM CDT SUN MAY 12 2013
AFTER HAVING BREEZY...DRYING AND UNSEASONABLY COOL WEATHER THIS
WEEKEND...INCLUDING FROST/FREEZE CONDITIONS TONIGHT ACROSS
WISCONSIN...CONCERN CONTINUES TO INCREASE ABOUT CRITICAL FIRE
WEATHER CONDITIONS ON TUESDAY. MOST LOCATIONS SHOULD SEE HIGHS
CLIMB INTO THE 80S...WITH SOME WEST OF THE MISSISSIPPI RIVER
REACHING 90. DEWPOINT FORECASTS REMAIN TRICKY...BUT MINIMUM
RELATIVE HUMIDITY VALUES SHOULD HAVE NO PROBLEM FALLING INTO THE
30 TO 40 PERCENT RANGE. IT IS POSSIBLE LOCATIONS SAY ALONG AND
WEST OF US-52 COULD END UP DROPPING TOWARDS 25 PERCENT. COMBINED
WITH SOUTHWEST WINDS OF 15 TO 20 MPH AND HIGHER GUSTS...THE
SITUATION BEARS WATCHING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ032-041-054-
061.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ017-029-033-
034-042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
FIRE WEATHER...AJ
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1235 PM CDT SUN MAY 12 2013
.DISCUSSION...
327 AM CDT
MAIN FORECAST CHALLENGES/CONCERNS ARE WITH THE COLD TEMPS AND
FROST TONIGHT WITH A FROST ADVISORY NOW IN PLACE FOR ALL OF THE
CWA TONIGHT...THE ANTICIPATED WARM UP THIS WEEK...AND SIGNS OF A
MORE ACTIVE WEATHER PATTERN BEGINNING TO APPEAR IN THE EXTENDED.
IN THE NEAR TERM...QUIET WEATHER ONGOING ACROSS THE CWA WITH
MOSTLY CLEAR SKIES IN PLACE OVER MUCH OF NORTHEAST ILLINOIS AND
NORTHWEST INDIANA. THE EXCEPTION IS NEAR THE WISCONSIN BORDER
WHERE MID LEVEL CLOUDS ARE TRYING TO SPILL INTO THE AREA THIS
MORNING. THIS IS IN RESPONSE TO SEVERAL WAVES OF ENERGY DROPPING
SOUTHEAST AROUND THE BASE OF THE STRONG UPPER LEVEL LOW TO THE
NORTHEAST. STEEP LOW/MID LEVEL LAPSE RATES STILL IN PLACE EARLY
THIS MORNING WITHIN THIS CYCLONIC WILL CONTINUE TO ALLOW FOR SOME
SCATTERED CLOUD DEVELOPMENT BUT PRIMARILY FOR AREAS IN FAR
NORTHEAST ILLINOIS...AS THIS LOCATION NORTHWARD IS WHERE THE BEST
FORCING/STEEPER LAPSE CURRENTLY RESIDE. ALTHOUGH THERE MAY BE
PERIODS OF THIS SCATTERED MID DECK OR EVEN AN ISOLATED AND BRIEF
CEILING...THINK SKIES SHOULD REMAIN MORE ON THE CLEARER SIDE
THROUGH MID MORNING. TEMPERATURES RIGHT NOW ARE STILL HOLDING
AROUND 40 DEGREES DESPITE THE CLEAR SKIES AND MUCH COLDER AIRMASS
IN PLACE. AS WAS EXPECTED...THE SURFACE LOW TO THE NORTHEAST WITH
TIGHT PRESSURE GRADIENT OVER THE CWA HAS ALLOWED FOR SURFACE WINDS
TO STAY UP NEAR THE 10KT RANGE. SO ONLY EXPECT TEMPS TO FALL A
COUPLE OF MORE DEGREES HERE THIS MORNING BEFORE RISING TO WELL
BELOW NORMAL MAX TEMPS IN THE LOW TO MID 50S TODAY. SHOULD BE A
RATHER QUIET DAY TODAY...ALTHOUGH LOW LEVEL LAPSE RATES REALLY
STEEPEN UP ONCE AGAIN TODAY ACROSS THE CWA. ONCE AGAIN...THESE
LAPSE RATES WITHIN THIS CYCLONIC FLOW WILL PROVIDE FOR SOME
STRATOCU DEVELOPMENT BY MID TO LATE MORNING WITH ANY CLEAR SKIES
BECOMING BROKEN/PARTLY SUNNY. EXPECT THIS TO BE THE CASE THROUGH
THE AFTERNOON AND INTO THE EARLY EVENING. ALTHOUGH CONDITIONS
APPEAR DRY AT THE MOMENT FOR THIS AFTERNOON...LATEST SHORT TERM
GUIDANCE IS TRYING TO INDICATE SOME ISOLATED SHOWER DEVELOPMENT
ACROSS NORTHEAST ILLINOIS LATER THIS AFTERNOON. NOT COMPLETELY
SOLD ON ANY WIDESPREAD DEVELOPMENT LATER THIS AFTERNOON AND SO
HAVE REMAINED DRY...BUT IT WOULD NOT BE OUT OF THE QUESTION FOR
SOME ISOLATED SHOWERS ACROSS NORTHEAST ILLINOIS...ESPECIALLY IF
ANY LOW LEVEL CONVERGENCE COULD DEVELOP WHICH THE RAP IS BEGINNING
TO SHOW.
ATTENTION SHIFTS TOWARDS ANOTHER COLD NIGHT TONIGHT AS FORECAST
TEMPS IN THE LOW TO MID 30S ARE FORECAST AS WELL AS A FROST
EXPECTED FOR THE ENTIRE CWA...MINUS THE WARMER METRO AREA. AS THE
LARGE UPPER LEVEL LOW AND ATTENDANT SURFACE LOW/TROUGH EXIT TO THE
EAST TONIGHT...SURFACE RIDGE SETTLES IN. WITH THIS IN PLACE EXPECT
SURFACE WINDS TO RAPIDLY DROP OFF THIS EVENING WITH TEMPS COOLING.
THERE IS SOME CONCERN THAT CLOUD COVER AND THE BEGINNING STAGES OF
WAA COULD AFFECT NIGHT TIME LOWS...BUT STILL FEEL THAT THESE
SHOULD NOT PLAY TOO MUCH OF A ROLE WITH TEMPS FALLING TONIGHT.
CLOUD DEVELOPMENT COULD POSSIBLY HANG ON INTO THE EVENING AT LEAST
TOWARDS 3Z TONIGHT BUT THEN BEGIN TO ERODE AND SHIFT TO THE EAST
TOWARDS MIDNIGHT...WITH ANY HIGH LEVEL CLOUD COVER APPROACHING
FROM THE WEST REMAINING TO THE WEST. ALSO...ALTHOUGH STRONG WAA
WILL BE OCCURRING TO THE WEST OVER IOWA...THIS SHOULD NOT AFFECT
AREAS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA TONIGHT. IN THE
END...SETTING THE STAGE FOR GOOD RADIATIONAL COOLING. SO HAVE
ISSUED A FROST ADVISORY FOR THE ENTIRE CWA...FROM 6Z TONIGHT TO
12Z MONDAY.
TEMPS WILL BEGIN TO RECOVER ON MONDAY AS THE PREVIOUSLY MENTIONED
WAA SHIFTS EAST TOWARDS THE CWA ON MONDAY...WITH TEMPS RISING BACK
INTO THE LOW TO MID 60S. HAVE MAINTAINED CHANCES FOR PRECIP MONDAY
NIGHT INTO EARLY TUESDAY AS THE WAA WING SHOULD SWING SOME
MOISTURE ACROSS PRIMARILY THE NORTHERN HALF OF THE CWA. SHOULD
REMAIN JUST SHOWERS WITH THUNDER NOT EXPECTED AS INSTABILITY IS
APPEARING TO REMAIN TO THE WEST. WITH STRONG WAA STILL OCCURRING
ACROSS THE AREA MONDAY NIGHT INTO TUESDAY...A RATHER WARM DAY IS
APPEARING TO BE LIKELY ON TUESDAY. HAVE RAISED MAX TEMPS FURTHER
FOR TUESDAY AND HAVE HIGHS IN THE MID TO UPPER 80S...AS THERMAL
AXIS WITH 850MB TEMPS NEAR 20C MOVING OVERHEAD. HAVE NOT PUT IN 90
DEGREE TEMPS FOR TUESDAY JUST QUITE YET AS THERE IS STILL SOME
UNCERTAINTY WITH THE EXTENT OF THIS THERMAL AXIS...BUT COULD
EASILY SEE THAT 90 DEGREE WEATHER INCLUDED IN THE FORECAST FOR
TUESDAY AT A LATER TIME. WEDNESDAY LOOKS WARM AGAIN WITH TEMPS
RISING TO THE 80S ONCE AGAIN...BUT WITH CONFIDENCE LOWERING EVEN
FURTHER. GUIDANCE BEGINS TO DIVERGE WITH HANDLING AN APPROACHING
SURFACE LOW AND FRONTAL BOUNDARY. THIS WILL IMPACT HIGHS FOR
WEDNESDAY AS WELL AS PRECIP CHANCES. A SLIGHT CHANCE FOR
THUNDERSTORMS HAS BEEN MAINTAINED DURING THE DAY WEDNESDAY...BUT
IT APPEARS THAT THERE WILL BE BETTER CHANCES FOR THUNDERSTORMS
WEDNESDAY NIGHT. BEYOND THIS POINT FROM THURSDAY INTO
SATURDAY...MODELS BEGIN TO DIVERGE FURTHER. DESPITE THIS MODEL
VARIABILITY...MODELS ARE AGREEING ON A WARMER AND MORE MOIST
AIRMASS REMAINING IN PLACE WITH 850MB DEWPOINTS REALLY INCREASING
ACROSS THE REGION AS WELL AS THE POTENTIAL SETUP FOR LINGERING
BOUNDARIES. THIS WILL HAVE TO BE RESOLVED ONCE GUIDANCE COMES INTO
BETTER AGREEMENT...BUT WITH THE GENERAL PATTERN IS BEGINNING TO
APPEAR MORE ACTIVE WITH PERIODS OF SHOWERS/THUNDERSTORMS POSSIBLE
INTO THE END OF THIS WEEK.
RODRIGUEZ
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* NORTHWEST WINDS GUSTING TO 18-20KT THIS AFTERNOON.
KREIN
//DISCUSSION...UPDATED 18Z...
A VERY QUIET WEATHER SETUP FOR AVIATION CONCERNS FOR THE PERIOD.
MAIN CONCERN WILL CONTINUE TO BE WIND DIRECTION AS WINDS CONTINUE
TO BE BRISK. HOWEVER...SUSTAINED WINDS AND GUSTS ARE DIMINISHING
THIS AFTERNOON AS HIGH PRESSURE CONTINUES TO BUILD ACROSS THE
MISSISSIPPI VALLEY. ALSO...LATEST SATELITE IMAGERY SHOWER DIURNAL
STRATOCU DEVELOPMENT...WITH A BKN DECK EXPECTED TO DEVELOP EARLY
THIS AFTERNOON...WHICH WILL ALSO HELP LIMIT MIXING. SO...THE
GENERAL TREND FOR WINDS WILL BE TO DECREASE THROUGH THE
AFTERNOON...WHILE BACKING SLIGHTLY TO OUT OF 300 DEGREES. WINDS
WILL THEN GO CALM AND SKIES WILL GO SKC OVERNIGHT.
KREIN
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* HIGH CONFIDENCE IN ALL FORECAST ELEMENTS
KREIN
//OUTLOOK FOR ORD/MDW FOR 00Z TUESDAY-12Z SUNDAY...UPDATED 12Z...
MONDAY NIGHT AND TUESDAY...VFR.
WEDNESDAY...SLIGHT CHANCE OF SHRA/TSRA.
THURSDAY THROUGH SATURDAY...A PERIOD OR TWO OF SHRA/TSRA POSSIBLE.
IZZI
&&
.MARINE...
255 AM CDT
SOME SHIP OBS AND COASTAL OBS ON EASTERN SHORE SUPPORT MAINTAINING
THE GALE WARNING AS IS THIS MORNING WITH CONTINUED UNSTABLE
CONDITIONS LIKELY TO ALLOW GALES TO LINGER INTO THE MORNING HOURS.
FAR NORTHERN LAKE MICHIGAN COULD SEE GALES LINGER INTO THE EARLY
AFTERNOON DUE TO TIGHTER GRADIENT BUT WINDS ACROSS THE LAKE SHOULD
BE TRENDING DOWNWARD THIS AFTERNOON INTO TONIGHT AS RIDGE AXIS
APPROACHES FROM THE WEST. RIDGE WILL MOVE ACROSS THE LAKE TONIGHT
INTO MONDAY WITH SOUTHERLY WINDS DEVELOPING AND STRENGTHENING AS
SEASONABLY STRONG LOW PRESSURE DEVELOPS OVER THE SOUTHERN CANADIAN
PLAINS TUESDAY. DESPITE FAIRLY TIGHT GRADIENT...SURGE OF VERY WARM
AIR OVER VERY COLD LAKE SHOULD KEEP WINDS AND WAVES SOMEWHAT IN
CHECK TUESDAY INTO WEDNESDAY.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FROST ADVISORY...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-
ILZ011-ILZ012-ILZ013-ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-
ILZ023-ILZ032-ILZ033-ILZ039...1 AM MONDAY TO 7 AM MONDAY.
IN...FROST ADVISORY...INZ001-INZ002-INZ010-INZ011-INZ019...1 AM
MONDAY TO 7 AM MONDAY.
LM...GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 3 PM SUNDAY.
SMALL CRAFT ADVISORY...NEARSHORE GARY TO MICHIGAN CITY IN UNTIL 3 PM SUNDAY.
&&
$$
VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE)
FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT:
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WWW.TWITTER.COM/NWSCHICAGO
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AREA FORECAST DISCUSSION
NWS MARQUETTE MI
406 PM EDT SUN MAY 12 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 404 PM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED AN AMPLIFIED PATTERN WITH A
RIDGE OVER WRN NOAM AND A TROUGH OVER THE EAST. THE MID LEVEL LOW
CENTER WAS SLOWLY MOVING OFF TO THE EAST OF CYSB INTO QUEBEC. AT THE
SFC...THE PRES GRADIENT ACROSS LAKE SUPERIOR WAS GRADUALLY WEAKENING
AS THE 998 MB LOW ALSO MOVES INTO QUEBEC AND A RIDGE RIDGE FROM NW
ONTARIO THROUGH WRN MN BUILDS INTO THE UPPER MS VALLEY. RADAR
INDICATED THAT THE LINGERING FLURRIES BTWN MQT-ESC-ISQ WERE
DIMINISHING AS DRIER AIR MOVES IN .
TONIGHT...EXPECT THAT THE REST OF THE LOWER CLOUDS WILL DISSIPATE
DURING THE LATE AFTERNOON AND EARLY EVENING...PER SATELLITE
TRENDS...BUT MAY LINGER A BIT LONGER THAN WHAT SHORT TERM MODEL LOW
LEVEL RH GUIDANCE SUGGESTS. WITH GOOD RADIATIONAL COOLING CONDITIONS
BY LATE THIS EVENING WEST AND OVER NIGHT EAST AND PWAT VALUES BELOW
0.25 INCH...MIN TEMPS SHOULD FALL TOWARD THE LOWER END OF GUIDANCE
AND NEAR RECORD VALUES. THE RECORD FOR THE NWS OFFICE ON 5/12 IS 24
AND ON 5/13 IS 25. READINGS INTO THE UPPER TEENS INTERIOR WEST TO THE
MID 20S EAST ARE EXPECTED WHILE TEMPS AROUND 30 PREVAIL NEAR THE
GREAT LAKES.
MONDAY...AS THE MID/UPPER LEVEL RIDGE OVER THE PLAINS BUILDS TO THE
EAST...A BROAD WAA PATTERN WILL DEVELOP OVER THE UPPER MS VALLEY AND
WRN GREAT LAKES. 295-305K ISENTRPOPIC ASCENT AHEAD OF A TROUGH
MOVING TOWARD MN WILL BRING INCREASING HIGH CLOUDS ACROSS UPPER MI
DURING THE AFTERNOON. THE INITIAL DRY LOW LEVELS AHEAD OF THE BAND
OF MOISTURE/ASCENT WILL LIMIT EASTWARD PROGRESSION OF THE LIGHT PCPN
BAND TO THE FAR WEST DURING THE LATE AFTERNOON WHERE ONLY SLIGHT
CHANCE POPS WERE INCLUDED.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 157 PM EDT SUN MAY 12 2013
SLY FLOW WILL DOMINATE BETWEEN A SFC RIDGE OVER THE ERN CWA AND A
TROUGH OVER THE MN/ND/SD BORDERS AT 00Z TUE. WAA AND ASSOCIATED THIN
BAND OF LIGHT SHOWERS WILL BE OVER THE WRN CWA. COVERAGE OF THESE
RAIN SHOWERS WILL BE LIMITED BY LIMITED MOISTURE...SO WILL KEEP POPS
ON THE LOWER SIDE SIMILAR TO LAST FORECAST. THE PRECIP MOVES TO THE
FAR ERN CWA BY 12Z TUE.
BY 00Z WED...A SHORTWAVE TROUGH AND SFC LOW WILL MOVE TO SRN
MANITOBA...BRINGING A WARM FRONT INTO THE CWA AND A COLD FRONT TO
CENTRAL MN. BY THIS TIME...850MB TEMPS WILL HAVE INCREASED TO AROUND
16C OVER THE WRN CWA AND 9C OVER THE ERN CWA /14C AND 11C WARMER
THAN 24 HOURS BEFORE...RESPECTIVELY/. THE WARM FRONT WILL MOVE
THROUGH THE CWA FOLLOWED SHORTLY AFTER BY THE COLD FRONT WED NIGHT
INTO EARLY WED. WHILE THUNDERSTORMS APPEAR LIKELY GIVEN INSTABILITY
AND STEEP LAPSE RATES...THERE IS SOME UNCERTAINTY WITH CONVECTIVE
STRENGTH. MODEL FORECAST SOUNDINGS INDICATE POTENTIAL FOR OVER
1000J/KG OF ELEVATED CAPE...BUT MODELS SHORT THE DRY SLOT ROTATING
THROUGH AROUND THE SAME TIME AS THE SHORTWAVE...BRINGING AN ELEVATED
MIXED LAYER THAT LEADS TO 100-200J/KG OF CIN. WHETHER THE COLD FRONT
CAN LIFT PARCELS THROUGH THE DRY LAYER AND THE EXACT TIMING OF THE
DRYER AIR REALLY LOWERS CONFIDENCE IN STRONGER THUNDERSTORMS.
ALSO...MODELS NOW AGREE FAIRLY WELL ON TIMING OF THE SYSTEM...BUT
VARY MORE SIGNIFICANTLY ON HOW FAR N OR S TO BRING THE
SYSTEM...WHICH IMPACTS POTENTIAL FORCING FOR ASCENT AND THE STRENGTH
OF THE LOW LEVEL JET. PRECIP DOES APPEAR LIKELY ENOUGH WED NIGHT TO
GO WITH LIKELY POPS /AT LEAST OVER THE NRN AND ERN CWA/...AND
THUNDER ALSO SEEMS LIKE A GOOD BET IN MOST LOCATIONS THAT RECEIVE
RAIN. DEFINITELY NOT SURE ON SEVERE POTENTIAL YET...BUT THERE IS
SOME INDICATION THAT ISOLATED SEVERE WX MAY BE POSSIBLE.
EVEN THOUGH 850MB TEMPS ARE COOLER DURING THE DAY WED THAN
TUE...GOOD MIXING AND SUNSHINE BEHIND THE COLD FRONT WILL LEAD TO
WARMER HIGH TEMPS AND LOWER RH VALUES...COMBINED WITH BREEZY WLY
WINDS. EXPECT HIGHS IN THE 70S INLAND...WITH AROUND 60 EXPECTED
CLOSER TO LAKE SUPERIOR. WILL CONTINUE TREND FROM PREVIOUS SHIFT OF
LOWERING DEW PTS LOWER GIVEN GOOD MIXING AND DRY AIRMASS BEHIND THE
FRONT...LEADING TO MIN RH VALUES IN THE 25-30 PERCENT /OR LOWER/
RANGE OVER INTERIOR CENTRAL AND WEST UPPER MI. INCREASED WINDS ON WED
TO GUSTS TO 30KTS OVER THE WRN CWA /COULD BE HIGHER IF NAM
VERIFIES...BUT IT IS ON THE STRONGER SIDE/. IT IS WORTH NOTING THAT
THE WARMEST TEMPS...LOWEST RH AND HIGHEST WINDS ARE EXPECTED OVER
THE INTERIOR WRN CWA...WHERE THE CHANCES FOR SIGNIFICANT PRECIP TUE
NIGHT ARE THE LOWEST. WILL NEED TO CONTINUE TO MONITOR CONDITIONS
FOR WED...BUT MAY SEE CRITICAL FIRE WEATHER CONDITIONS OVER AT LEAST
PORTIONS OF UPPER MI.
HIGH TEMPS WILL BE A A DEGREE OR TWO COOLER THU...BUT STILL EXPECT
70S INLAND AND AROUND 60 NEAR LAKE SUPERIOR. MIN RH VALUES LOOK TO
BE SIMILAR TO WED ON THE LOW END OF THE COMFORT SCALE FOR FIRE
WX...BUT WINDS WILL BE MUCH LIGHTER AS BROAD HIGH PRESSURE SETTLES
OVER THE REGION.
FOR FRI THROUGH SUN...JUST LOADED A CONSENSUS OF MODEL GUIDANCE DUE
TO INCREASED UNCERTAINTY AND GREATER FOCUS ON FORECAST TUE-THU.
OVERALL...EXPECT TEMPS AROUND SEASONAL NORMALS /A REGULAR SEASONAL
NORMAL...NOT THIS SEASONS NORMAL/ WITH HIGHS IN THE 60S TO LOW 70S.
PRECIP WILL BE POSSIBLE AS FRONTAL ZONES WILL BE NEARBY...BUT
GETTING TOO SPECIFIC AT THIS POINT WOULD BE FUTILE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN MAY 12 2013
AS A RIDGE AND DRIER AIR MOVES INTO THE REGION FROM THE WEST THIS
AFTERNOON...ANY LINGERING CIGS AT CMX/SAW WILL GIVE WAY TO SCT CLOUDS BY
MID TO LATE AFTERNOON. SO...MVFR CIGS AT KSAW WILL BE LAST TO SCATTER
OUT. CLEAR SKIES WILL THEN PREVAIL THIS EVENING THROUGH MON MORNING.
IT WILL REMAIN BLUSTERY AT CMX/SAW THROUGH THIS AFTERNOON WITH NW
GUSTS TO AROUND 30 MPH.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 404 PM EDT SUN MAY 12 2013
GALES WILL SUBSIDE BY EARLY EVENING AND WINDS OVER THE EAST WILL
DROP BELOW 20 KNOTS OVERNIGHT AS A RIDGE BUILDS INTO THE REGION
WINDS WILL INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE
NIGHT AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR
ON WED. A WARM FRONT SLIDING ACROSS LAKE SUPERIOR TUESDAY NIGHT AHEAD
OF THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS ARE EXPECTED AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
158 PM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 157 PM EDT SUN MAY 12 2013
SLY FLOW WILL DOMINATE BETWEEN A SFC RIDGE OVER THE ERN CWA AND A
TROUGH OVER THE MN/ND/SD BORDERS AT 00Z TUE. WAA AND ASSOCIATED THIN
BAND OF LIGHT SHOWERS WILL BE OVER THE WRN CWA. COVERAGE OF THESE
RAIN SHOWERS WILL BE LIMITED BY LIMITED MOISTURE...SO WILL KEEP POPS
ON THE LOWER SIDE SIMILAR TO LAST FORECAST. THE PRECIP MOVES TO THE
FAR ERN CWA BY 12Z TUE.
BY 00Z WED...A SHORTWAVE TROUGH AND SFC LOW WILL MOVE TO SRN
MANITOBA...BRINGING A WARM FRONT INTO THE CWA AND A COLD FRONT TO
CENTRAL MN. BY THIS TIME...850MB TEMPS WILL HAVE INCREASED TO AROUND
16C OVER THE WRN CWA AND 9C OVER THE ERN CWA /14C AND 11C WARMER
THAN 24 HOURS BEFORE...RESPECTIVELY/. THE WARM FRONT WILL MOVE
THROUGH THE CWA FOLLOWED SHORTLY AFTER BY THE COLD FRONT WED NIGHT
INTO EARLY WED. WHILE THUNDERSTORMS APPEAR LIKELY GIVEN INSTABILITY
AND STEEP LAPSE RATES...THERE IS SOME UNCERTAINTY WITH CONVECTIVE
STRENGTH. MODEL FORECAST SOUNDINGS INDICATE POTENTIAL FOR OVER
1000J/KG OF ELEVATED CAPE...BUT MODELS SHORT THE DRY SLOT ROTATING
THROUGH AROUND THE SAME TIME AS THE SHORTWAVE...BRINGING AN ELEVATED
MIXED LAYER THAT LEADS TO 100-200J/KG OF CIN. WHETHER THE COLD FRONT
CAN LIFT PARCELS THROUGH THE DRY LAYER AND THE EXACT TIMING OF THE
DRYER AIR REALLY LOWERS CONFIDENCE IN STRONGER THUNDERSTORMS.
ALSO...MODELS NOW AGREE FAIRLY WELL ON TIMING OF THE SYSTEM...BUT
VARY MORE SIGNIFICANTLY ON HOW FAR N OR S TO BRING THE
SYSTEM...WHICH IMPACTS POTENTIAL FORCING FOR ASCENT AND THE STRENGTH
OF THE LOW LEVEL JET. PRECIP DOES APPEAR LIKELY ENOUGH WED NIGHT TO
GO WITH LIKELY POPS /AT LEAST OVER THE NRN AND ERN CWA/...AND
THUNDER ALSO SEEMS LIKE A GOOD BET IN MOST LOCATIONS THAT RECEIVE
RAIN. DEFINITELY NOT SURE ON SEVERE POTENTIAL YET...BUT THERE IS
SOME INDICATION THAT ISOLATED SEVERE WX MAY BE POSSIBLE.
EVEN THOUGH 850MB TEMPS ARE COOLER DURING THE DAY WED THAN
TUE...GOOD MIXING AND SUNSHINE BEHIND THE COLD FRONT WILL LEAD TO
WARMER HIGH TEMPS AND LOWER RH VALUES...COMBINED WITH BREEZY WLY
WINDS. EXPECT HIGHS IN THE 70S INLAND...WITH AROUND 60 EXPECTED
CLOSER TO LAKE SUPERIOR. WILL CONTINUE TREND FROM PREVIOUS SHIFT OF
LOWERING DEW PTS LOWER GIVEN GOOD MIXING AND DRY AIRMASS BEHIND THE
FRONT...LEADING TO MIN RH VALUES IN THE 25-30 PERCENT /OR LOWER/
RANGE OVER INTERIOR CENTRAL AND WEST UPPER MI. INCREASED WINDS ON WED
TO GUSTS TO 30KTS OVER THE WRN CWA /COULD BE HIGHER IF NAM
VERIFIES...BUT IT IS ON THE STRONGER SIDE/. IT IS WORTH NOTING THAT
THE WARMEST TEMPS...LOWEST RH AND HIGHEST WINDS ARE EXPECTED OVER
THE INTERIOR WRN CWA...WHERE THE CHANCES FOR SIGNIFICANT PRECIP TUE
NIGHT ARE THE LOWEST. WILL NEED TO CONTINUE TO MONITOR CONDITIONS
FOR WED...BUT MAY SEE CRITICAL FIRE WEATHER CONDITIONS OVER AT LEAST
PORTIONS OF UPPER MI.
HIGH TEMPS WILL BE A A DEGREE OR TWO COOLER THU...BUT STILL EXPECT
70S INLAND AND AROUND 60 NEAR LAKE SUPERIOR. MIN RH VALUES LOOK TO
BE SIMILAR TO WED ON THE LOW END OF THE COMFORT SCALE FOR FIRE
WX...BUT WINDS WILL BE MUCH LIGHTER AS BROAD HIGH PRESSURE SETTLES
OVER THE REGION.
FOR FRI THROUGH SUN...JUST LOADED A CONSENSUS OF MODEL GUIDANCE DUE
TO INCREASED UNCERTAINTY AND GREATER FOCUS ON FORECAST TUE-THU.
OVERALL...EXPECT TEMPS AROUND SEASONAL NORMALS /A REGULAR SEASONAL
NORMAL...NOT THIS SEASONS NORMAL/ WITH HIGHS IN THE 60S TO LOW 70S.
PRECIP WILL BE POSSIBLE AS FRONTAL ZONES WILL BE NEARBY...BUT
GETTING TOO SPECIFIC AT THIS POINT WOULD BE FUTILE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN MAY 12 2013
AS A RIDGE AND DRIER AIR MOVES INTO THE REGION FROM THE WEST THIS
AFTERNOON...ANY LINGERING CIGS AT CMX/SAW WILL GIVE WAY TO SCT CLOUDS BY
MID TO LATE AFTERNOON. SO...MVFR CIGS AT KSAW WILL BE LAST TO SCATTER
OUT. CLEAR SKIES WILL THEN PREVAIL THIS EVENING THROUGH MON MORNING.
IT WILL REMAIN BLUSTERY AT CMX/SAW THROUGH THIS AFTERNOON WITH NW
GUSTS TO AROUND 30 MPH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...TITUS
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
136 PM EDT SUN MAY 12 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 549 AM EDT SUN MAY 12 2013
WV IMAGERY AND RUC ANALYSIS SHOW STRONG SHORTWAVE/CLOSED LOW SYSTEM
NE OF LAKE SUPERIOR EARLY THIS MORNING. ENHANCEMENT ON THE BACK EDGE
OF THIS SYSTEM COMBINED WITH COLD ADVECTION IN ITS WAKE...HELPED
PRODUCE SOME MODERATE SNOW ACCUMULATION FROM NEGAUNEE/ISHPEMING EAST
THROUGH ALGER AND NRN SCHOOLCRAFT COUNTIES EARLIER THIS MORNING.
HOWEVER...IN THE PAST HR OR TWO RADAR RETURNS HAVE DIMINISHED
DRAMATICALLY IN AREAL EXTENT AND INTENSITY. HERE AT NWS MQT...SNOW
HAS DIMINISHED TO FLURRIES AND EXPECT THIS IS THE CASE AT MANY
LOCATIONS BASED ON RADAR RETURNS. LATEST VAD WIND PROFILE FROM MQT
RADAR ALSO SHOWS INDICATION OF SHARP LOWERING OF SUBSIDENCE
INVERSION FROM 9-10 KFT TO 6 KFT IN PAST HR WHICH IS ALSO CONSISTENT
WITH DIMINISHED RADAR RETURNS.
TODAY...GIVEN RECENT DIMINISHING RADAR TRENDS AND FACT THAT MODELS
SHOW BEST Q-VECT CONV FOR LAKE ENHANCEMENT TO BE MOVING EAST WITH
TIME THIS MORNING...HAVE DECIDED TO CANCEL THE WINTER WEATHER
ADVISORIES FOR NORTH CENTRAL COUNTIES. MOST PLACES FROM MQT COUNTY
EASTWARD WILL BE HARD PRESSED TO SEE MORE THAN HALF AN INCH OF
ADDITIONAL SNOW ACCUMULATION WITH ONLY A FEW LINGERING FLURRIES
NOTED TO THE WEST. UPDATED POPS TO REFLECT SHARP DIMINISHING TREND
TO PCPN THIS MORNING. LINGERING CYCLONIC FLOW AND -10C 8H TEMPS
MOVING ACROSS LAKE SUPERIOR COULD STILL SUPPORT PLENTY OF LAKE
STRATOCU CLOUDS THROUGH THE MORNING HRS...ESPECIALLY FOR
EASTERN COUNTIES DOWNWIND OF LONGER NNW FETCH ACROSS ERN LAKE
SUPERIOR. SHARP SUBSIDENCE/DRYING WITH A TRANSITION TO MORE NEUTRAL
OR ANTICYCLONIC FLOW FROM THE WEST BY AFTERNOON SHOULD ALLOW FOR
CLEARING SKIES FROM THE WEST THIS AFTERNOON. FAIRLY TIGHT NW PRES
GRAD ON THE BACKSIDE OF EXITING LOW WILL KEEP WINDS GUSTING TO NEAR
35 MPH OVER THE ERN HALF COUNTIES ESPECIALLY NEAR LAKE SUPERIOR.
OTHERWISE...UNSEASONABLY COLD CONDITIONS WILL CONTINUE WITH HIGHS
RANGING FROM AROUND 40 NORTH AND EAST TO MID 40S SOUTH CENTRAL.
TONIGHT...GIVEN RELATIVELY COLD HIGH TEMPS EXPECTED TODAY...SFC
RIDGING AND ASSOCIATED CLEARING BUILDING IN FROM THE W SHOULD ALLOW
SFC TEMPS TO PLUMMET TONIGHT TO RECORD OR NEAR RECORD LOW READINGS
ESPECIALLY OVER THE WRN CWA. LEANED ON THE LOWER END OF MODEL
GUIDANCE FOR MIN TEMPS WITH EXPECTED READINGS IN THE MID TO UPPER
TEENS OVER THE TYPICALLY COLD WRN INTERIOR LOCATIONS AND LOWER TO
MID 20S ACROSS THE REST OF THE INTERIOR CWA. TEMPS WILL STAY A BIT
WARMER NEAR THE GREAT LAKES...GENERALLY IN THE UPPER 20S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 549 AM EDT SUN MAY 12 2013
UPPER PATTERN FEATURING WESTERN CONUS RIDGING AND EASTERN CONUS
TROUGHING BECOMES MORE ZONAL THROUGH THE WEEK...RESULTING IN
WARMING TREND FOR UPPER GREAT LAKES. AS THE UPPER PATTERN BECOMES
MORE ZONAL EXPECT SFC LOW AND FRONTAL BOUNDARIES TO MOVE FROM
CENTRAL CANADA ACROSS THE GREAT LAKES TUESDAY THROUGH THURSDAY. BEST
CHANCE OF RAIN IN THIS PATTERN SHOULD BE LATER TUESDAY THROUGH
TUESDAY NIGHT AS WARM FRONT SLIDES ACROSS UPPER GREAT LAKES. EXTENT
OF COOLING BEHIND COLD FRONT WEDNESDAY INTO THURSDAY UNCERTAIN. EVEN
THE MODELS THAT ARE SHOWING THE MOST EMPHATIC COOLING /GFS AND NAM/
SHOW NOTHING TO THE EXTENT OF CURRENT COOLDOWN THAT IS CURRENTLY
OCCURRING. SO...BEYOND THIS TASTE OF WINTER AFFECTING THE REGION
THIS MORNING...EXPECT EXTENDED TO HOLD ONLY LIQUID PRECIPITATION.
HIGH PRESSURE BEGINS THE EXTENDED PERIOD OVER WESTERN GREAT LAKES.
RIDGE AXIS HEADS ACROSS REST OF GREAT LAKES BY MONDAY NIGHT ALLOWING
WARM AIR ADVECTION/RETURN FLOW TO DEVELOP. THROUGH DAY 2 LEANED ON
THE NAM/GFS SOUNDINGS TO TRY TO GAGE PRECIP CHANCES. MOISTURE
ADVECTION FOCUSED MAINLY ALOFT H85-H7 MONDAY NIGHT. SOME LGT SHOWERS
SEEM LIKELY IN MAX ADVECTION AREA MOVING WEST TO EAST ACROSS CWA.
ONCE MID-LEVEL MOISTURE/LIFT IS STRIPPED AWAY...SHALLOW MOISTURE
MAINLY BLO H9 IS ALL THAT IS LEFT ON TUESDAY. HINTS FROM MODELS THAT
MOISTURE MAY MIX OUT BY AFTN. LOWERED POPS BASED ON LIMITED MOISTURE
INTO TUESDAY AFTN. NEXT SURGE OF MOISTURE/TEMPERATURE ADVECTION AND
ELEVATED INSTABILITY COULD BRING SHOWERS/TSRA OVER GENERALLY WESTERN
CWA LATE TUESDAY AFTN. SE WINDS AHEAD OF WARM FRONT WITH MORE
INFLUENCE OFF LK MICHIGAN FOR MUCH OF CWA SHOULD KEEP TEMPS FROM
GETTING TOO WARM EVEN WITH ONLY SCT CLOUDS BY AFTN. WARMEST READINGS
INTO THE 70S INLAND WEST AND SOUTHWEST CWA WITH LESS LAKE MODIFIED
COOLER AIR. UPR 50S TO UPR 60S ELSEWHERE.
WARM FRONT PASSAGE/MAXIMUM LOW-LEVEL MOISTURE AND TEMP ADVECTION
STILL ON TRACK FOR TUESDAY NIGHT. HAS LOOKED THIS WAY FOR A WHILE
NOW. STILL THINKING THIS IS THE BEST CHANCE FOR SHOWERS AND TSRA
ACROSS CWA...BUT STILL MAY NOT BE WIDESPREAD EVENT FOR ALL CWA. SOME
DIFFERENCE HOW FAR SOUTH SHORTWAVE TROUGH/MID-LEVEL HEIGHT FALLS DIP
INTO UPR LAKES AND THIS IMPACTS SOUTHERN EXTENT OF PRIMARY UPPER
LEVEL JET AND ASSOCIATED DIVERGENCE TO ENHANCE PRECIP. PLACED LIKELY
POPS OVER NORTH AND EAST AND KEPT POPS SCATTERED FARTHER SOUTH. GIVEN
H85 DWPNTS OVER +12C AND 1-6KM MUCAPES OVER 1000J/KG AND SINCE AXIS
OF 925-850MB WIND MAX IS OVERHEAD...SHRA AND TSRA CANNOT BE COUNTED
OUT ANYWHERE THOUGH. STRONGST WINDS ALOFT ARE MORE OVER LAKE SUPERIOR
AND NORTH INTO ONTARIO SO THINK THIS IS WHERE BETTER CHANCE OF
STRONGER STORMS WOULD BE LOCATED. SEEMS THAT LIGHTNING AND HEAVY
DOWNPOURS WILL BE THE PRIMARY HAZARDS. THOUGH WBZERO HEIGHTS
11-12KFT IS ON THE HIGHER SIDE TO SEE LARGE HAIL...IT IS POSSIBLE
GIVEN STRONGER SHEAR AND H7-H5 LAPSE RATES OVER 7C/KM.
GOOD AGREEMENT THAT AREA OF ENHANCED PRECIP SWIFTLY CROSSES THE AREA
LATER TUESDAY NIGHT WITH COLD FRONTAL PASSAGE NOT TOO FAR BEHIND ON
WEDNESDAY MORNING. SUBSTANTIAL CLEARING IN THE OFFING ON WEDNESDAY
IN WAKE OF THE FRONT. 00Z ECMWF TRENDED SLIGHTLY TOWARD COLDER GFS
IDEA FOR H85 TEMPS IN WAKE OF COLD FRONT...BUT EVEN SO...EXPECT
SUNSHINE AND DEEP MIXING TO OFFSET THIS AND LEAD TO MAX TEMPS INTO
THE 70S SOUTHWEST AND SOUTH CENTRAL. READINGS IN THE 60S CLOSER TO
LK SUPERIOR. WINDS MAY END UP STRONGER THAN WHAT CONSENSUS SHOWED
BUT LEFT THEM ALONE FOR NOW. DID GO WITH LOWER BIAS CORRECTED MOS
DWPNTS IN THE AFTN GIVEN THE DEEP MIXING.
THURSDAY AND FRIDAY....A BIT UNSETTLED POTENTIALLY. PRIMARY SFC
FRONTAL BOUNDARY WILL REMAIN SOUTH OF UPR MICHIGAN. YET SINCE THE
AREA IS ON SOUTHERN EDGE OF TROUGH OVR CANADA...THE JET STREAM IS
TOO CLOSE BY TO NOT HAVE AT LEAST SLIGHT CHANCE POPS. MODELS HAVE
SHOWN SOME QPF FROM TIME TO TIME...ESPECIALLY LATER FRIDAY AND
FRIDAY NIGHT AS SECONDARY SFC TROUGH DIPS SOUTH ACROSS THE UPPER
GREAT LAKES.
BY NEXT WEEKEND THE MAIN ISSUE WILL BE INFLUENCE OF DEVELOPING LOW
PRESSURE OVER PLAINS. 12Z ECMWF FARTHER TO THE EAST...WHILE GFS AND
WPC HAND DRAWN PROGS KEEP LOW SHUNTED MORE OVER THE PLAINS AND SFC
RIDGE OVER THE UPR LAKES. CONSENSUS OF MODELS WHICH HAS DOUBLE
WEIGHTING OF THE TYPICALLY BETTER PERFORMING ECMWF SHOWS INCREASING
CHANCES OF SHOWERS BY LATER IN THE WEEKEND. TEMPS TO END THE
EXTENDED WILL BE AROUND NORMAL...THOUGH MAY REMAIN SLIGHTLY BELOW
NORMAL ALONG LK SUPERIOR DUE TO PREVAILING NORTHERLY SFC WINDS.
EVEN IF IT DOES END UP BELOW NORMAL...NO SNOW IS IN THE
FORECAST...WHICH IS CERTAINLY WELCOME NEWS FOR THOSE WEARY OF THE
WINTER THAT HAS BEEN RELUCTANT TO END.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 134 PM EDT SUN MAY 12 2013
AS A RIDGE AND DRIER AIR MOVES INTO THE REGION FROM THE WEST THIS
AFTERNOON...ANY LINGERING CIGS AT CMX/SAW WILL GIVE WAY TO SCT CLOUDS BY
MID TO LATE AFTERNOON. SO...MVFR CIGS AT KSAW WILL BE LAST TO SCATTER
OUT. CLEAR SKIES WILL THEN PREVAIL THIS EVENING THROUGH MON MORNING.
IT WILL REMAIN BLUSTERY AT CMX/SAW THROUGH THIS AFTERNOON WITH NW
GUSTS TO AROUND 30 MPH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 549 AM EDT SUN MAY 12 2013
GALES CONTINUE OVER EASTERN SECTIONS INTO THIS AFTN THEN WINDS
DIMINISH BY TONIGHT AS HIGH PRESSURE RIDGE MOVES ACROSS. WINDS
INCREASE OUT OF THE S/SE TO 25 KTS MON NIGHT THROUGH TUE NIGHT
AHEAD OF A LOW PRESSURE SYSTEM MOVING NORTH OF LAKE SUPERIOR ON
WED. WARM FRONT SLIDING ACROSS LK SUPERIOR TUESDAY NIGHT AHEAD OF
THE LOW MAY RESULT IN A FEW STRONGER THUNDERSTORMS. LIGHTNING AND
HEAVY DOWNPOURS WOULD BE THE PRIMARY HAZARDS. EXPECT WINDS TO SHIFT
WESTERLY ON WEDNESDAY BEHIND THE COLD FRONT. POSSIBLE THAT GUSTS
COULD REACH 30 KTS. LIGHTER WINDS AGAIN LATE IN THE WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR LSZ249>251-266-267.
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>245-264-
265.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...JLA
AVIATION...JLB
MARINE...JLA
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1219 PM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 820 AM CDT SUN MAY 12 2013
LIGHT SHOWERS CONTINUE TO SLIDE THROUGH PORTIONS OF THE REGION
THIS MORNING. A FEW LIGHTNING STRIKES HAVE BEEN REPORTED WITH
THESE SHOWERS. THEREFORE WENT AHEAD AND ADDED ISOLATED THUNDER TO
THE FORECAST THIS MORNING.
UPDATE ISSUED AT 543 AM CDT SUN MAY 12 2013
HAVE BEEN WATCHING TEMPERATURES WARM PRIOR TO DAWN AS THE CLOUDS
HAVE MOVED IN. THIS WAS PRETTY MUCH EXPECTED THAT WE WOULD WARM
ONCE THE CLOUDS MOVED IN THIS MORNING. THUS WE HAVE EXPIRED THE
FROST ADVISORY ACROSS NORTHWEST ZONES WHERE TEMPERATURES HAVE NOW
RISEN FROM THE LOWER AND MID 30S INTO THE MID AND UPPER 30S.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 305 AM CDT SUN MAY 12 2013
THE PRIMARY FORECAST CONCERNS CENTER AROUND AREAS OF FROST ACROSS
NORTHEAST ZONES THIS MORNING...AS WELL AS ISOLATED MORNING
SPRINKLES FROM THE TRI CITES WEST AND SOUTH.
AS OF 3 AM...AN AREA OF SFC HIGH PRESSURE WAS SITUATED OVER
EASTERN NEBRASKA RESULTING IN CALM WINDS ALONG AND EAST OF HIGHWAY
281...WHICH IS RESULTING IN GOOD RADIATIONAL COOLING SINCE THIS AREA
HAS ALSO BEEN LARGELY CLOUD FREE THUS FAR. THE 3 AM TEMPERATURE AT
YORK WAS DOWN TO 34F AND IT IS LIKELY THAT LOW LYING AREAS ALONG
HIGHWAY 81...ESPECIALLY NORTH OF HIGHWAY 6 ARE ALREADY STARTING TO
SEE SOME FROST. HOWEVER...CLOUDS ARE ON THE INCREASE WEST OF
HIGHWAY 81 AND SHOULD QUICKLY MOVE OVER THE REST OF OUR FORECAST
AREA PRIOR TO DAWN. THIS WILL LIKELY RESULT IN RISING TEMPERATURES
ONCE THE CLOUDS MOVE IN NEAR DAWN. THEREFORE...FROST WILL BE
CONFINED TO LOW LYING AREAS OF OUR FAR NORTHEAST AND SHOULD NOT
LAST LONG. WILL LIKELY BE ABLE TO END THE FROST ADVISORY A BIT
EARLY.
PRECIPITATION CHANCES THIS MORNING ARE LOW AND THE RADAR HAS BEEN
RATHER QUIET THROUGH THE OVERNIGHT HOURS...WITH JUST A MINOR
RETURN OR TWO. MOST FORECAST MODELS CONTINUE TO INDICATE NO
QPF...BUT THE HRRR DOES SHOW A FEW ISOLATED SHOWERS.
THEREFORE...LOWERED POPS AND WILL JUST CALL FOR A SLIGHT CHANCE OF
ISOLATED SPRINKLES EARLY THIS MORNING. THERE COULD BE A FEW
SHOWERS AROUND...BUT JUST DO NOT THINK MOST OF THEM WILL MEASURE
MORE THAN A TRACE.
THE CLOUDS WILL BE MORE OF A MORNING FEATURE WITH CLEARING SKIES
BY AFTERNOON AND WARMER TEMPERATURES THANKS TO RETURN
SOUTHEASTERLY FLOW ON THE BACK SIDE OF THE SFC HIGH AS WELL AS
UPPER LEVEL RIDGING. AFTERNOON HIGHS WILL RANGE FROM THE UPPER 60S
EAST TO THE MID 70S WEST.
TONIGHT...THE UPPER RIDGE WILL CONTINUE TO BUILD INTO THE HIGH
PLAINS...SFC WINDS WILL REMAIN SOUTHERLY AND LOW TEMPERATURES WILL
BE MORE MILD. LOW TEMPERATURES WILL PRIMARILY BE IN THE MID TO
UPPER 40S.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 AM CDT SUN MAY 12 2013
MAIN STORY: WE ARE ENTERING A DECIDELY MORE SUMMERLIKE PATTERN THAT
OFFERS POTENT HEAT AND MULTIPLE TSTM CHANCES. TEMPS WILL AVERAGE
ABOVE NORMAL THRU NEXT SAT WITH MUCH ABOVE NORMAL MON-TUE AS THE
ENTIRE FCST AREA WILL REACH 90F FOR THE FIRST TIME THIS SEASON.
AREAS W OF HWY 281 PROBABLY REACH OR EXCEED 90 BOTH DAYS. THEN THE
FOCUS SHIFTS TO TSTM CHANCES WITH A WRN TROF NEXT WEEKEND THAT COULD
THREATEN SEVERE WX.
PATTERN: THE PNA IS CURRENTLY PEAKING POSITIVE WITH A HIGH-AMPLITUDE
WRN N AMERICA RIDGE AND ERN TROF...WITH A CUT-OFF LOW OVER NRN MEX.
THE +PNA WILL HEAD BACK TO NEUTRAL BY THE MIDDLE OF NEXT WEEK...
INDICATING DEAMPLIFICATION OF THE LONG-WAVE /LGWV/ FLOW. TEMPS WILL
BE WARMER THAN NORMAL THRU NEXT SUN THEN SHOULD RETURN TO NEAR TO
POSSIBLY A LITTLE COOLER THAN NORMAL BY MON 5/20.
ALOFT: THE HIGH-AMPLITUDE WRN USA RIDGE WILL GET MOWED DOWN BY A
POTENT NEGATIVE TILT PV ANOMALY THAT MOVES ONSHORE IN THE PAC NW
LATE MON. THIS PV ANOMALY WILL TRACK E ACROSS SRN CANADA TUE
INITIATING ZONAL FLOW FOR WED-THU. IN THE MEANTIME...THE NRN MEX
CUT-OFF LOW WILL BECOME MOBILE AND HEAD ACROSS THE SRN PLAINS...TOO
LATE TO INFUSE ANY MSTR THIS FAR N. A BROAD TROF THEN DEVELOPS OVER
THE WRN USA FRI AND LASTS INTO EARLY THE FOLLOWING WEEK. MULTIPLE
LOW AMPLITUDE PV ANOMALIES WILL SHOULD INSTIGATE PERIODIC TSTM
THREATS.
SFC: THE WARM FRONT DEPARTS TO THE E MON AS LOW PRES MIGRATES ACROSS
SRN CANADA. ITS ASSOCIATED COOL FRONT WILL MOVE THRU TUE NGT AND
BECOME STATIONARY NEAR THE NEB-KS BORDER WED-THU. IT MAY HEAD BACK N
TO NEAR THE NEB-SD BORDER FRI-SAT. THE DRYLINE WILL INTERSECT THIS
FRONT JUST W OF THE FCST AREA.
MODELS: 00Z GEM / 12Z AND 00Z EC / 18Z AND 00Z GFS / 12Z AND 00Z
UKMET ARE IN GOOD AGREEMENT ON THE OVERALL THEME THRU 00Z/SAT...
DEAMPLIFICATION TO ZONAL FLOW THEN A MODEST AMPLITUDE TROF MOVING
INTO THE WRN USA NEXT WEEKEND. TYPICAL TIMING DIFFERENCES BEGIN TO
SHOW UP NEXT SAT WITH THE 00Z GFS FASTER THAN ALL THE OTHER GUIDANCE
/AND EVEN ITS 18Z RUN/ ADVANCING THE TROF INTO THE ROCKIES.
HAZARDS: NOTHING DEFINABLE AT THIS POINT BUT MULTIPLE CHANCES FOR
TSTMS EXIST TUE NGT-SAT. IT/S TOO EARLY TO PIN DOWN LOCATION/TIMING/
COVERAGE AND INTENSITY...BUT ODDS ARE INCREASING THAT WE COULD HAVE
TO DEAL WITH AT LEAST ONE EPISODE OF SEVERE.
THE DAILY DETAILS...
MON: THE WARM FRONT WILL BISECT THE FCST AREA AT DAYBREAK. ANY
FRONTAL CLOUDS WILL CLEAR THE AREA AS THE FRONT DEPARTS TO THE E.
THIS WILL RESULT IN A SUNNY VERY WARM DAY...BUT W OF HWY 281 IT WILL
BE HOT /90-95F/. +24C AT H8 AND 582 HGTS AT H5.
TUE: SUNNY AND HOT. 93-98F. +26C AT H8 AND 582 HGTS AT H5. H8 TEMPS
2 STANDARD DEVIATIONS ABOVE NORMAL. HIGHS WILL BE 25F ABOVE NORMAL.
GRI AND HSI WILL BE WITHIN ABOUT 4F OF RECORD HIGHS BUT THEY SHOULD
BE SAFELY OUT OF REACH. GRI 99-1941. HSI 97-1941.
TUE NGT: COOL FRONTAL PASSAGE. IT/S PROBABLY DRY MOST LOCATIONS. AN
ISOLATE TSTM IS POSSIBLE.
WHILE THIS COOL FRONT WILL END THE HEAT...TEMPS WILL STILL REMAIN
8-15F ABOVE NORMAL WED-SAT.
WED: POSSIBLY A LEFT OVER SHWR OR TSTM ALONG THE FRONT?
THU-SAT: OVERALL SHOULD AVERAGE P/CLOUDY AND DRY MOST OF THE TIME.
HOWEVER...MULTIPLE EPISODES OF TSTMS APPEAR POSSIBLE ALONG THE
FRONT/DRYLINE.
OF PARTICULAR INTEREST IS THE RISING HGTS OVER THE ERN USA. THIS
WILL PREVENT TUE NGT/S COOL FRONT FROM PENETRATING FAR TO THE S.
HIGH PRES WILL PARK ITSELF OFF THE CAROLINA/S...SETTING UP SEVERAL
DAYS OF UNINTERRUPTED RICH GULF MSTR FLUX N INTO THE PLAINS. BY WED
AFTN H8 DWPTS OF 8+C WILL BE IN PLACE WITH SFC DWPTS INTO THE 50S
THU AND AROUND 60 FRI-SAT. DIURNAL OSCILLATIONS IN THE LLJ WILL
PROBABLY TRIGGER MCS ACTIVITY OVER THE NRN/CNTRL PLAINS. INSTABILITY
WILL BUILD A LITTLE MORE EACH DAY.
SEVERE: AM GROWING INCREASINGLY CONCERNED ABOUT THE POTENTIAL FOR A
COUPLE EPISODES OF SVR TSTMS IN THE THU-MON TIME FRAME. THU-SAT
WOULD PROBABLY TAKE THE FORM OF A FORWARD PROPAGATING MCS. SUN COULD
BE SUBSTANTIALLY MORE INTERESTING AS THE LFQ OF A 120 KT ULJ EJECTS
INTO THE CNTRL PLAINS.
IF WE DO GET AN MCS THRU HERE IT COULD SERIOUSLY IMPACT OUR TEMPS
THE FOLLOWING DAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1220 PM CDT SUN MAY 12 2013
VFR CONDITIONS WILL CONTINUE THROUGHOUT THE TAF PERIOD. AS A
SURFACE LOW PRESSURE SYSTEM SKIRTS TO OUR SOUTHWEST...SUSTAINED SOUTHEAST
WINDS WILL CONTINUE AROUND 12 KTS THROUGHOUT THE AFTERNOON. WINDS
WILL THEN DECREASE TO NEAR 10 KTS FOR THE EVENING HOURS. AN UPPER
LEVEL RIDGE WILL CONTINUE TO SHIFT EASTWARD TOWARDS THE PLAINS
TODAY WHICH WILL RESULT IN AT LEAST SOME PARTIAL HIGH LEVEL CIRRUS
CLOUDS ACROSS THE AREA OVERNIGHT.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE...SALTZMAN
SHORT TERM...WESELY
LONG TERM...HALBLAUB
AVIATION...SALTZMAN
AREA FORECAST DISCUSSION
NWS TULSA OK
1239 PM CDT SUN MAY 12 2013
.DISCUSSION...
LARGE UPPER TROUGH OVER THE EASTERN CONUS CONTINUES TO SHIFT EAST
TODAY. NW FLOW ALOFT PREVAILS OVER THE PLAINS IN BETWEEN THE
TROUGH TO THE EAST AND THE AMPLIFYING RIDGE OVER THE WEST. HIGH
BASED SHOWERS AND EVEN A FEW RUMBLES OF THUNDER ARE OBSERVED TO
OUR NORTH AND WEST...MOST LIKELY DUE TO MID LVL WARM
ADVECTION/FRONTOGENESIS ALONG THE NW FLOW BAROCLINIC ZONE. WILL
MONITOR LIGHTNING ACTIVITY TO SEE IF THUNDER NEEDS TO BE INSERTED
INTO THE GRIDS. CURRENT FORECAST 20 POP FOR SHOWERS OVER NE OK AND
NW AR LOOKS GOOD BASED ON RECENT HRRR MODEL DATA. NO MAJOR CHANGES
HAVE BEEN REQUIRED TO THE GOING FORECAST.
LACY
&&
.PREV DISCUSSION... /ISSUED 1207 PM CDT SUN MAY 12 2013/
DISCUSSION...
THE 18Z TAF DISCUSSION CAN BE FOUND BELOW.
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS WILL PREVAIL WITH SCT TO BKN MID CLOUDS AOA 10KFT.
ISOLD TO WDLY SCT SHRA COULD BE NEAR THE NE OK AND NW AR TAF SITES
THIS AFTERNOON SO INSERTED VCSH. LIGHT WINDS TODAY WILL SWITCH TO
SOUTHWEST AND BECOME GUSTY AFT 15Z MONDAY AS LEE TROF DVLPS ON THE
HI PLNS.
LACY
PREV DISCUSSION... /ISSUED 542 AM CDT SUN MAY 12 2013/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
VFR CONDITIONS EXPECTED THROUGH THE PERIOD...WITH INCREASING MID
CLOUDS EXPECTED DURING THE AFTERNOON. SMALL CHANCE OF SHRA ACROSS
NORTHEAST OKLAHOMA AND NORTHWEST ARKANSAS...BUT CONFIDENCE AND
EXPECTED COVERAGE LOW ENOUGH TO NOT INCLUDE ATTM.
PREV DISCUSSION... /ISSUED 304 AM CDT SUN MAY 12 2013/
DISCUSSION...
COOL START THIS MORNING AS SURFACE HIGH PRESSURE CONTINUES TO
BUILD INTO THE REGION WITH MOSTLY CLEAR SKIES/NORTHWEST FLOW
ALOFT. WEAK UPPER LEVEL DISTURBANCE WILL DIVE SOUTH INTO THE
AREA TODAY WITH INCREASING MID CLOUDS AND THE POTENTIAL FOR A FEW
ISOLATED/WIDELY SCATTERED SHOWERS INTO THE AFTERNOON HOURS. THIS
WILL KEEP HIGH TEMPERATURES ON THE MILD SIDE...ESPECIALLY ACROSS
FAR NORTHEAST OKLAHOMA/NORTHWEST ARKANSAS WHERE THE CLOUD COVER IS
EXPECTED TO BE THE THICKEST/MORE WIDESPREAD.
WARMING TREND WILL DEVELOP MONDAY AS UPPER RIDGE QUICKLY BUILDS
INTO THE PLAINS WITH UNSEASONABLY WARM/BREEZY CONDITIONS TUESDAY
AS GUSTY SOUTHWEST WINDS DEVELOP. UPPER LOW...CURRENTLY OVER THE
BAJA OF MEXICO...WILL LIFT INTO OKLAHOMA ON WEDNESDAY WITH SCATTERED
SHOWERS/THUNDERSTORMS POSSIBLE. PRECIPITATION CHANCES WILL LINGER
INTO THURSDAY BEFORE UPPER LOW WEAKENS/SHIFTS EAST OF THE AREA BY
FRIDAY.
SLOW WARMING TREND RETURNS INTO THE WEEKEND AS UPPER RIDGE BUILDS
BACK INTO THE SOUTHERN PLAINS. PRECIPITATION CHANCES APPEAR TO BE
LIMITED WITH MILD NIGHTS/WARM AFTERNOONS EXPECTED BOTH FRIDAY AND
SATURDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 51 85 63 86 / 10 10 0 10
FSM 50 83 57 87 / 10 10 0 10
MLC 52 85 62 86 / 10 10 0 0
BVO 48 83 56 87 / 10 10 10 10
FYV 43 78 56 83 / 10 10 0 10
BYV 46 78 57 86 / 10 10 0 10
MKO 50 83 60 86 / 10 10 0 10
MIO 47 81 58 86 / 10 10 10 10
F10 52 85 62 85 / 10 10 0 10
HHW 51 83 60 84 / 10 10 0 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...30
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
256 PM MDT SUN MAY 12 2013
.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 255 PM MDT SUN MAY 12 2013
MASSIVE WESTERN CONUS UPPER RIDGE CONTINUES TO PUSH
EAST WITH DEEP LAYER THETA-E RIDGING ONGOING. LEE SIDE TROUGH
WILL ADVECT EAST AWAY FORM THE ROCKIES ON THE LEADING EDGE OF
UPPER LEVEL HEIGHT RISES...WITH A STRONG UPPER LEVEL TROUGH
EXPECTED TO ADVANCE INTO THE NORTHERN PLAINS MONDAY
NIGHT...SUPPORTING ANOTHER MORE PRONOUNCED LL TROUGH INTO THE
REGION. OVERALL...MAINLY DRY WEATHER EXPECTED...SAVE FOR PORTIONS
OF THE BLACK HILLS WHERE LL THETA-E ADV COUPLED WITH STEEPENING
MID LEVEL LAPSE RATES AND LOCAL OROGRAPHIC CONVERGENCE MAY
SUPPORT ISOLD SHRA/TS LATE THIS AFTERNOON/EARLY EVENING AND AGAIN
MONDAY AFTERNOON/EVENING. OTHERWISE...A SIG WARM NOSE ASSOCIATED
WITH THE ADVANCING RIDGE IS EXPECTED TO KEEP CONVECTION AT BAY
ELSEWHERE.
LATE THIS AFTERNOON/TONIGHT...REMOVED LOW POPS OVER THE
CENTRAL/SOUTHERN BH. NEARLY ALL HIRES MODELS DO NOT GENERATE ANY
CONVECTION...WITH THE NAM BEING THE ONLY MODEL/OUTLIER THAT DOES.
LATEST RAP BUFR PROGS INDICATE MID LEVEL WARMING IS STRONGER/FASTER
THAN PREVIOUS INDICATIONS...WITH A DOWNTREND IN CU NOTED IN SAT
TRENDS. OTHERWISE...A WARM NIGHT EXPECTED WITH LOWS IN THE 50S AT
MANY PLACES. THERE IS A SMALL POTENTIAL FOR AN ELEVATED SHOWER
ACROSS THE FAR NORTH GIVEN THETA-E ADV AT THE BASE OVER THE GROWING
WARM NOSE WITH NEGATIVE SW INDICES. HOWEVER...GIVEN THE LOW
POTENTIAL HAVE LEFT OUT AND WILL LET THE NEXT SHIFT ASSESS.
MONDAY...LEAD LL TROUGH WILL ADVECT EAST ACROSS THE AREA IN THE
MORNING...WITH ONGOING DEEP LAYER WAA. INCREASED LL MOISTURE MAY BE
SUFFICIENT ENOUGH TO GENERATE ISOLD CONVECTION OVER THE BH...ESP
WITH A WEAK MESO LOW AS INDICATED IN THE NAM. RETAINED SLIGHT CHANCE
POPS THERE. OTHERWISE...VERY WARM CONDITIONS EXPECTED WITH LOW TO
MID 90S OVER THE SD PLAINS...COOLER WEST. CURRENT FORECAST TEMPS
SURPASSES THE RECORD OF 92 AT THE RAPID CITY AIRPORT...NEARING THE
DOWNTOWN RECORD OF 94. A VERY WARM NIGHT IS IN STORE FOR MONDAY
NIGHT...WITH LOWS IN THE 60S AT MANY PLACES GIVEN ONGOING SFC
PRESSURE FALLS PER THE ADVANCING DEEP NORTHERN STREAM UPPER IMPULSE.
THIS WILL SUPPORT A MIXED BL WITH GUSTY WINDS POTENTIALLY AT MANY
LOCATIONS...ESP OVER THE NORTHERN BH FOOTHILLS...GIVEN A NEAR 5 MB
SFC PRESSURE DIFFERENTIAL FROM THE BH TO THE PLAINS. RECORD HIGH
MIN/S MAY BE SET AT RAPID CITY.
&&
.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 255 PM MDT SUN MAY 12 2013
UPPER LEVEL RIDGE BREAKS DOWN BY TUESDAY MORNING AS A SURFACE LOW
PASSES TO THE NORTH AND A STRONG COLD FRONT SLIDES QUICKLY ACROSS
THE FORECAST AREA DURING THE MORNING. STRONG NORTHWEST WINDS CAN BE
EXPECTED ACROSS THE NORTHWEST AND WEST CENTRAL SOUTH DAKOTA PLAINS
BEHIND THE FRONT. THE STRONGEST WINDS LOOK TO BE NEAR THE ND BORDER.
HAVE DECIDED TO ISSUE A HIGH WIND WATCH FOR HARDING AND PERKINS
COUNTIES...WHERE SUSTAINED WINDS OF 40 MPH OR MORE LOOK POSSIBLE...
ESPECIALLY DURING THE LATE MORNING AND EARLY AFTERNOON HOURS. HIGH
TEMPERATURES WILL RANGE FROM THE LOWER 70S OVER FAR NORTHWESTERN SD
AND PORTIONS OF NORTHEASTERN WY TO THE UPPER 80S ACROSS SOUTH
CENTRAL SD. DEPENDING ON THE EXACT TIMING OF THE FRONT AND HOW
QUICKLY THE DRIER AIR PUSHES IN BEHIND THE FRONT...THERE IS SOME
POTENTIAL FOR CRITICAL FIRE WEATHER CONDITIONS TO DEVELOP ACROSS
PORTIONS OF THE SD PLAINS TUESDAY AFTERNOON. WILL LET LATER SHIFTS
HAVE A LOOK AT UPDATED MODEL DAYA FOR THIS POTENTIAL AND WHETHER A
FIRE WX WATCH MAY BE NEEDED.
MORE SEASONABLE TEMPS ARE EXPECTED FOR THE REMAINDER OF THE
WEEK...THOUGH STILL ABOVE AVERAGE...AS AREA REMAINS UNDER ZONAL
FLOW. WEAK DISTURBANCES WITHIN THIS FLOW WILL BRING SOME CHANCES FOR
MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS LATE IN THE
WEEK...WITH CHANCES LIKELY INCREASING BY THE WEEKEND. LATEST GFS AND
ECMWF BOTH CONTINUE TO SHOW A STRONGER UPPER TROF IMPACTING THE
REGION FROM LATE FRIDAY THROUGH THE WEEKEND...BRINGING THE POTENTIAL
FOR MORE WIDESPREAD PCPN AND OUR FIRST SEVERE WX OF THE SEASON.
&&
.AVIATION...FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON
ISSUED AT 255 PM MDT SUN MAY 12 2013
VFR CONDITIONS ARE EXPECTED THROUGH MONDAY MORNING.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...HIGH WIND WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON
FOR SDZ001-002.
WY...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...26
AVIATION...26
AREA FORECAST DISCUSSION
NWS SPOKANE WA
223 PM PDT Sun May 12 2013
.SYNOPSIS...
A cold front will arrive this evening, and bring breezy
conditions to much of the Inland Northwest. On Monday a vigorous
upper level disturbance will bring the first period of widespread
precipitation to the region in over three weeks with locally heavy
downpours and thunderstorms. The arrival of cooler, more seasonal
temperatures Tuesday through the upcoming weekend will allow many
rivers to recede.
&&
.DISCUSSION...
Tonight: There will be two features of note where showers will
focus through this evening into tonight. This first is a mid level
front that has stalled across northwest Oregon into north-central
Washington. We have seen some very light shower activity along the
eastern edge of this front and much of this precip is likely
evaporating before reaching the surface. Radar imagery showed some
enhancement over southwest Washington around 1:30 in the
afternoon indicating a bit more lift across this area possibly due
to a little ripple moving in. The HRRR model takes this
enhancement moves it northeast ward over Wenatchee to Colville
through this evening. As a result, I kept some minor mention of
showers along this area; however, I am not that confident that we
will generate much in the way of measurable rainfall along the front.
The second area of note is a ridge axis in the equivalent
potential temperature field between 850-700 mbs from northeast
Oregon, across the Central Panhandle and into western Montana.
Visible satellite imagery is showing signs of some surface based
convection beginning to fire along this axis and should continue
to develop through at least the early evening hours. There isn`t
much of a trigger coming through to keep convection going through
the night, but the mid level front looks to nudge a bit more
eastward this evening. This may be enough to keep showers going
through the evening from the Northeast Blue Mountains into the
Central Panhandle Mountains. I kept a mention of isolated
thunderstorms in these areas as sounding profiles would suggest
that it is possible. The HRRR model does show the possibility of
40+ dbz echoes as well, but I am not too excited for thunderstorms
this evening. /SVH
Monday and Monday night...This period promises to be a very active
weather period for much of the forecast area as a transition into
a much cooler and spring-like weather pattern arrives. Satellite
indicates a deep and long fetch of moisture impacting the
Northwest Pacific Coast this afternoon...ahead of a deep Gulf of
Alaska trough with the outriding showers creeping into the
forecast area this evening. This situation will be aggravated on
Monday as a vigorous upper level short wave now faintly visible as
a digging wave near 150W tears into the region providing copious
dynamic support with jet divergence...cyclonic diffluence and
differential PVA as well as a healthy surface cold front.
Precipitable water values available for exploitation by this lift
will be on the order of an inch or more...almost 200 percent of
normal. The confluence of all these elements will bring a number
of meteorological inconveniences to the region Monday afternoon
and evening.
Rain showers...
For the first time in weeks a very moist air mass will be
exploited by synoptic forcing into a dense area of hefty and
widespread shower activity...mainly focused over the eastern and
northern zones...but with hit-and-miss showers possible just about
anywhere in the region. On average most locations in the western
basin will experience only a few hundredths of an inch...but
amounts may exceed 1/4 to 1/2 inch east of a line from Republic
to Pomeroy and near the Cascade Crest...with some locations being
run over by multiple showers through the afternoon.
Thunderstorms...While the thunder potential will be fairly small
at any given location...the best chance for appreciable surface
based instability on the order of a few hundred Joules/Kg will be
over the southeastern zones during the afternoon and evening
hours. The magnitude of the forcing and wind shear in the lower
atmosphere suggests that any storms that get going south of a line
from about La Crosse to Mullan Pass have the potential to become
organized and strong producers of hail and gusty winds. north of
this line there will likely be too much cloud cover early in the
day to generate significant SB CAPE any any storms will be hit-
and-miss isolated embedded cells in the predominant shower
activity. These storm cores may also produce brief torrential
downpours but will likely also be fast movers for only a remote
threat of flash flooding.
Synoptic wind...The surface cold front will cross the region from
west to east during the afternoon period. Windy and gusty conditions
will develop over the deep basin during the afternoon and over the
eastern basin in the late afternoon and early evening hours as the
precipitation band exits to the east. The gradient magnitude and
gust potential from mixing does not appear to support Wind
Advisory criteria at this time...but solid 15 to 25 mph sustained
winds with gusts possibly as high as 40 mph will be possible into
the evening over exposed locations of the basin during the
evening hours.
Monday night...After the evening activity dies down...windy
condiitons will gradually abate to merely breezy and should keep
overnight lows elevated even with partial clearing.
Tuesday through Wednesday...A general zonal flow regime off the
Pacific will settle over the region during this period. This flow
should keep shower activity to a minimum over the basin...with a
chance of mountain showers (of the snow variety on the higher
peaks) each afternoon and evening north and east of the basin. No
further organized storms or frontal complexes are forecast through
Wednesday. The main story will be cooler and more seasonably
normal temperatures with occasionally breezy conditions. /Fugazzi
Wednesday night to Sunday: A progressive pattern with mean
continued shower chances, especially in the mountains, and near
seasonal temperatures. Models point to at least 2 organized
disturbances entering the West: one around Thursday and Friday and
another toward the weekend. There remains disagreement over
precise timing and track. Regardless embedded smaller-scale
vorticity maxima slip by. With Moisture and instability deepens
later Thursday and especially Friday, with PWATs rising to
120-170% of normal and CAPE values between 100-400 J/kg roughly
across north-central and east WA and north ID. Combined with any
forcing that comes through this will lead to an above average
threat of shower, with a chance of thunderstorms mixed in. Subtle
ridging develops going into Saturday before the next wave rides in
Sunday. This suggests a brief shift in the precipitation threat to
the mountains going into Saturday and early Sunday, before being
chances are renewed by later Sunday. Yet given limited agreement
over precise timing I kept PoPs closer to climatological values
between Saturday and early Sunday. This means while precipitation
chances decline from Friday, they do not end. The main exception
looks to be in the lee of the Cascades and deer Columbia Basin
where the westerly flow and its shadowing effects will hold PoPs
lower. /J. Cote`
&&
.AVIATION...
18Z TAFS: A mid level front will stall over the region today from
KEAT into the mountains of NE WA. Very light rain or sprinkles is
expected ahead of the front, which may impact the KEAT and KMWH
taf sites. Some isolated showers and thunderstorms may begin to
fire off over the higher terrain of the northeast Blue Mountains
over into the Idaho Panhandle after 21Z, but confidence is low as
there is some CIN to overcome without much of a kicker pushing
through. Breezy westerly winds are expected this afternoon as well
with gusts up to 25 to 30 mph possible. /SVH
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 67 41 62 43 66 / 10 80 50 0 10 10
Coeur d`Alene 52 68 43 62 41 67 / 20 80 50 10 10 10
Pullman 51 69 40 61 40 65 / 10 80 50 0 10 10
Lewiston 58 79 44 71 45 74 / 20 70 40 0 10 10
Colville 50 67 43 67 39 72 / 30 80 60 10 10 20
Sandpoint 49 65 42 62 39 67 / 30 80 80 20 10 10
Kellogg 53 68 42 59 40 64 / 20 80 70 10 10 10
Moses Lake 55 72 46 70 44 74 / 20 40 10 0 0 0
Wenatchee 55 70 47 69 45 72 / 10 60 10 0 10 10
Omak 49 71 42 69 39 73 / 10 60 20 10 10 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 232 PM CDT SUN MAY 12 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE HIGH
PRESSURE STRETCHING FROM SOUTH-CENTRAL CANADA TO THE WESTERN GULF
COAST EARLY THIS AFTERNOON WHILE LOW PRESSURE PEELS AWAY OVER
QUEBEC. AS CYCLONIC FLOW ABATES AND DRIER AIR BUILDS IN FROM THE
WEST...WIDESPREAD MORNING STRATO-CU HAS BEEN RETREATING TO THE
NORTHEAST...TURNING SKIES MOSTLY CLEAR TO PARTLY CLOUDY OVER MUCH OF
CENTRAL AND NORTHEAST WISCONSIN. PLENTY OF CLEAR SKIES BENEATH THE
SURFACE HIGH OFF TO THE WEST...WHICH WILL MOVE INTO THE AREA
TONIGHT. EVEN FARTHER WEST...A WARM FRONT OVER THE LEE OF THE
ROCKIES WILL ENTER THE REGION TOMORROW AFTERNOON. FIRST CONCERN
IS TEMPS TONIGHT...FOLLOWED BY SMALL PRECIP CHANCES TOMORROW
AFTERNOON.
TONIGHT...HIGH PRESSURE OVER THE GREAT PLAINS WILL SHIFT ACROSS THE
WESTERN HALF OF WISCONSIN TONIGHT. AS CLOUDS CONTINUE TO MIX OUT
THIS AFTERNOON...SKIES WILL BECOME CLEAR AND WINDS WILL BECOME LIGHT
AND VARIABLE BY EARLY TO MID-EVENING. GOOD RADIATIONAL CONDITIONS
WILL THEN EXIST FOR THE REST OF THE NIGHT. LOW TEMPS UPSTREAM OVER
WESTERN WISCONSIN AND MINNESOTA WERE MOSTLY AT OR BELOW 32 DEGREES
AND EXPECT SIMILAR READINGS LATE TONIGHT. TEMPS WERE ALSO IN THE 34
TO 36 DEGREE RANGE OVER THE FOX VALLEY AND LAKESHORE LAST
NIGHT...WHEN THERE WAS CONSIDERABLY MORE WIND AND CLOUDS. WILL NOT
HAVE THIS LUXURY TONIGHT...SO FIGURE TEMPS WILL FALL BELOW FREEZING
ACROSS MOST OF THE CWA. WILL EXPAND THE FREEZE WARNING.
MONDAY...HIGH PRESSURE WILL SLIDE TO THE EAST ACROSS THE CENTRAL
GREAT LAKES. WARM ADVECTION WILL RAMP UP ON THE BACKSIDE OF THE
HIGH AT THE SAME TIME AS MID AND HIGH CLOUDS SPILL OVER THE
MID-LEVEL RIDGE AXIS. AS A RESULT...WILL SEE A SLOW INCREASE OF
CLOUDS OVER THE COURSE OF THE DAY. AFTER 21Z...ENOUGH MOISTURE
ADVECTION LOOKS TO TAKE PLACE TO NEARLY SATURATE THE COLUMN OVER
CENTRAL AND NORTH-CENTRAL WISCONSIN. MID-LEVEL LAPSE RATES ARE VERY
POOR...BUT MID-LEVEL FGEN APPEARS SUFFICIENT FOR THE POSSIBILITY OF
SCATTERED LIGHT SHOWERS DEVELOPING. WILL INCREASE POPS INTO THE
40-50 PERCENT RANGE. THERE IS A FAIRLY LARGE RANGE IN GUIDANCE FOR
TEMPS TOMORROW AFTERNOON...BETWEEN THE COLD ECMWF AND WARM NAM.
SPLITTING THE DIFFERENCE SHOULD GET TEMPS CLOSE AND WILL GO WITH
HIGHS IN THE UPPER 50S TO LOW 60S BUT COOLER LAKE SIDE.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 232 PM CDT SUN MAY 12 2013
PCPN TRENDS MONDAY NIGHT INTO TUESDAY NIGHT...THE POTENTIAL FOR
SVR TSTMS TUESDAY NIGHT...GUSTY WINDS ON WEDNESDAY...PCPN TRENDS
NEXT WEEKEND...AND TEMPERATURES THROUGHOUT THE PERIOD ARE THE
MAIN FCST CONCERNS.
STRONG H8 WAA/MOISTURE CONVERGENCE WILL BRING A BAND OF SHOWERS THROUGH
THE AREA ON MONDAY NIGHT. ALTHOUGH THE RAIN WILL NOT LAST LONG AND QPF
AMOUNTS ARE EXPECTED TO BE LIGHT...FELT THAT POPS NEEDED TO BE RAISED
A LITTLE BIT. WAA/ISENT LIFT WILL CONTINUE ON TUESDAY AS A WARM FRONT
LIFTS INTO WISCONSIN. THIS FRONT IS EXPECTED TO MOVE INTO CENTRAL WI
LATE IN THE AFTERNOON. DESPITE SOME PERSISTENT FORCING...AN
INCREASINGLY CAPPED ATMOSPHERE AND LATE ARRIVAL OF THE INSTABILITY
AXIS PRECLUDES ADDING ANYTHING MORE THAN SLGT CHC/CHC POPS...MAINLY
OVER NORTHERN WI. TEMPERATURES WILL VARY GREATLY...WITH READINGS IN
THE MID 50S TO LOWER 60S NEAR THE LAKE...AND INLAND TEMPS RANGING
FROM THE UPPER 60S FAR NE WI TO THE LOWER TO MIDDLE 80S IN C WI.
THE WARM FRONT WILL LIFT NORTH TUESDAY...QUICKLY FOLLOWED BY THE COLD
FRONTAL PASSAGE DURING THE LATE EVENING AND OVERNIGHT HOURS. ELEVATED
CAPE OF 1500-2000 J/KG...VERY STEEP LAPSE RATES OF 7-8 C/KM...DEEP
LAYER SHEAR OF 40-50+ KTS AND 0-3 KM HELICITIES OF 400-500 WILL
PROVIDE PLENTY OF SUPPORT FOR SEVERE TSTMS...BUT CAPPING MAY BE
PROHIBITIVE FOR CONVECTIVE INITIATION. BEST CASE SCENARIO FROM THE
NAM AND A FEW OF THE SREF ENSEMBLE MEMBERS SHOW CINH OF 40-70
J/KG FOR A PARCEL LIFTED FROM THE 850-800 MB LEVEL OVER FAR
NORTHERN WI...BUT OTHER FCST SOUNDINGS SHOWED MUCH HIGHER CINH...
EVEN FROM ELEVATED PARCELS. WILL CONTINUE WITH CHC POPS TUESDAY
EVENING...AND A MENTION OF THE SVR TSTM POTENTIAL IN THE HAZARDOUS
WEATHER OUTLOOK...BUT HAVE TO ACKNOWLEDGE THE POTENTIAL FOR A MAINLY
DRY FCST. ANY PCPN THAT DOES DEVELOP WILL COME TO AN END OVERNIGHT
AS THE COLD FRONT SHIFTS EAST.
CAA...AN INCREASING NW PRESSURE GRADIENT AND DEEP MIXING WILL LEAD
TO A BREEZY/WINDY DAY ON WEDNESDAY. MIXING THROUGH 825-775 MB SUPPORTS
HIGH TEMPS IN THE LOWER TO MIDDLE 70S IN MOST LOCATIONS.
THE COLD FRONT WILL SETTLE SOUTH OF WISCONSIN FROM WEDNESDAY THROUGH
FRIDAY...AS ANOTHER COLD FRONT SAGS SOUTH OUT OF CANADA. WITH THE
REGION IN BETWEEN SYSTEMS...EXPECT A GENERALLY DRY PERIOD OVER THE
LATTER HALF OF THE WORK WEEK...WITH TEMPERATURES AT OR A LITTLE
ABOVE NORMAL.
LOW PRESSURE IS EXPECTED TO APPROACH FROM THE CENTRAL PLAINS THIS
WEEKEND...AND REACH THE IOWA VCNTY BY SUNDAY. AS THIS HAPPENS...
THE FRONT THAT STALLED TO OUR SOUTH WILL LIFT BACK INTO SOUTHERN
WISCONSIN...ALONG WITH ITS ASSOCIATED MOISTURE/ELEVATED INSTABILITY.
THIS SHOULD LEAD TO SHOWERS AND SCT TSTMS OVER THE REGION...ALONG
WITH COOLER TEMPERATURES DUE TO EAST WINDS AND ABUNDANT CLOUD COVER.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1230 PM CDT SUN MAY 12 2013
SCATTERED TO BROKEN CLOUDS BETWEEN 3500 FT AND 5000 FT WILL
GRADUALLY DISSIPATE DURING THE AFTERNOON. THIS WILL SET UP A CLEAR
AND COLD NIGHT. FROST WILL LIKELY FORM ON AIRCRAFT LATE TONIGHT.
MONDAY WILL START OUT SUNNY THOUGH MIDDLE AND HIGH CLOUDS WILL BE
ON THE INCREASE THROUGH THE DAY. A FEW SHOWERS ARE POSSIBLE OVER
CENTRAL AND NORTH-CENTRAL WISCONSIN LATE IN THE AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ020-022-030-
031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......KIECKBUSCH
AVIATION.......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 AM CDT SUN MAY 12 2013
.UPDATE...
ISSUED AT 1146 AM CDT SUN MAY 12 2013
WILL EXPAND FROST ADVISORY WEST TO INCLUDE WABASHA...WINONA...
HOUSTON...ALLAMAKEE AND CLAYTON COUNTIES ON WEST SIDE OF THE MS
RIVER. TERRAIN IN THESE COUNTIES INCLUDES A LOT OF SHELTERED
VALLEYS DUE TO THE STEEP TERRAIN AND TRIBUTARY RIVERS/STREAMS
FLOWING TOWARD THE MS RIVER. WINDS IN THESE VALLEYS LIKELY TO STAY
DECOUPLED THRU THE NIGHT...WITH STRONG RADIATIONAL COOLING AND COLD
AIR DRAINAGE. PATCHY TO AREAS OF FROST EXPECTED IN THESE COUNTIES
WITH LOWS IN THE LOWER 30S...NOT THAT DIFFERENT FROM NEIGHBORING
AREAS/COUNTIES ON THE EAST SIDE OF THE MS RIVER.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MAIN FORECAST CONCERN IS ON FROST/FREEZE CONDITIONS TONIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED RIDGING OVER THE WESTERN U.S. INTO ALBERTA WHILE ANOMALOUSLY
DEEP TROUGHING WAS PRESENT FROM HUDSON BAY INTO THE WESTERN GREAT
LAKES REGION. THE FORECAST AREA LIES ON THE BACK SIDE OF THE
TROUGHING...BUT STILL EAST OF THE INFLECTION POINT...WHICH RESULTS
IN NORTHWEST FLOW FROM THE SURFACE TO 500MB. THE FLOW CONTINUED TO
DRAG COLDER AIR SOUTHEAST WITH RAP 850MB TEMPS RANGING FROM -3C OVER
NORTHEAST IOWA TO -9C IN TAYLOR COUNTY WISCONSIN. DESPITE THE COLD
850MB TEMPS...READINGS ARE GENERALLY IN THE MID 30S TO AROUND 40...
STAYING UP BECAUSE OF THAT NORTHWEST WIND OF 5-10 KT AT THE SURFACE
KEEPING THE BOUNDARY LAYER MIXED. A LOT OF DRY AIR CONTINUES TO FLOW
IN TOO ON THE NORTHWEST WINDS FROM HIGH PRESSURE IN THE PLAINS.
DEWPOINTS ARE IN THE TEENS ACROSS MUCH OF THE DAKOTAS INTO MN AND
20S OVER WISCONSIN. COMBINATION OF THE WIND...TEMPERATURES AND DRY
AIR PRECLUDING ANY FROST DEVELOPMENT THUS FAR. THE AFOREMENTIONED
DRY AIR IS ALSO QUITE DEEP...REFLECTIVE FROM 00Z SOUNDINGS AT BIS...
ABR AND MPX HAVING PRECIPITABLE WATER VALUES OF 0.1-0.2 INCHES...OR
20-40 PERCENT OF NORMAL. THIS DRY AIR HAS HELPED CLEAR SKIES OUT
WEST OF WISCONSIN. SCT-BKN CLOUDS HAVE BEEN FLOWING ACROSS WISCONSIN
IN THE CYCLONIC FLOW IN THE UPPER TROUGH. FARTHER TO THE WEST UNDER
THE UPPER RIDGE...00Z SOUNDINGS FROM SAN FRANSISCO TO SALT LAKE CITY
AND NORTH TO GREAT FALLS MT ALL REPORTED 850MB TEMPS OF 20C OR
GREATER. THESE ARE 1.5-2.5 STANDARD DEVIATIONS ABOVE NORMAL.
BOTH THE UPPER RIDGE AND ANOMALOUSLY DEEP TROUGH ARE PROGGED TO
PROGRESS EASTWARD DURING THE NEXT 24 HOURS...PUSHED ALONG BY A
FAIRLY POTENT SHORTWAVE TROUGH APPROACHING THE PACIFIC NORTHWEST
COAST AT 12Z MONDAY. IT APPEARS THIS EVENING IS WHEN THE INFLECTION
POINT BETWEEN THE UPPER RIDGE AND DEEP TROUGH WILL REACH THE
FORECAST AREA. THIS MEANS TO PLAN ON THE SURFACE HIGH OVERHEAD AT
ABOUT THE SAME TIME.
TODAY...THE COMBINATION OF DRY AIR AND BEING FARTHER AWAY FROM THE
COLD POOL OF THE UPPER TROUGH WILL RESULT IN SUNNY SKIES. SINCE THE
AREA STAYS IN A GRADIENT AHEAD OF THE SURFACE HIGH AND WE HAVE FULL
SUN FOR DEEP MIXING...ANOTHER BREEZY DAY IS LIKELY...BUT NOT NEARLY
AS WINDY AS YESTERDAY. TEMPERATURES ARE DEFINITELY GOING TO STAY ON
THE COOL SIDE...THOUGH...WITH 850MB TEMPS HOLDING STEADY THROUGH
18Z. HIGHS SHOULD END UP VERY SIMILAR TO YESTERDAY.
TONIGHT...A REALLY GOOD RADIATIONAL COOLING SETUP IS FORECAST. WITH
THE SURFACE HIGH MOVING OVER THE AREA DURING THE EVENING...WINDS
WILL DECOUPLE EVERYWHERE. ADDITIONALLY...WE HAVE ALL OF THE DRY AIR
ACCOMPANYING THE SURFACE HIGH. THUS...TEMPERATURES SHOULD PLUMMET
DURING THE EVENING HOURS AFTER SUNSET. NOW...AFTER MIDNIGHT...THE
SURFACE RIDGE BEGINS TO PUSH EAST INTO CENTRAL WISCONSIN. THIS MEANS
A SOUTHERLY WARM ADVECTION FLOW WILL COMMENCE OVER WESTERN PORTIONS
OF THE FORECAST AREA. THEREFORE...OUR WISCONSIN COUNTIES CONTINUE TO
LOOK THE MOST FAVORABLE FOR THE COLDEST CONDITIONS...AND THE COLDEST
OVERALL OVER CENTRAL WISCONSIN. STAYED TOWARDS THE COLD SIDE OF
GUIDANCE FOR LOWS. GIVEN THE CONSISTENCY FOR TONIGHT TO BE COLD...
HAVE ISSUED FREEZE WARNINGS FOR THE PREVIOUS FREEZE WATCH AREA AND A
FEW EXTRA COUNTIES WHERE TEMPS ARE NOW FORECAST COLDER...WITH FROST
ADVISORIES FOR THE REST OF OUR WISCONSIN COUNTIES.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 320 AM CDT SUN MAY 12 2013
MONDAY THROUGH TUESDAY NIGHT...THE UPPER RIDGING OVER THE WESTERN
U.S. IS PROGGED TO CONTINUE TO GET PUSHED EASTWARD WHILE FLATTENING
WITH TIME. THIS IN RESPONSE TO THE POTENT SHORTWAVE OFF THE PACIFIC
NORTHWEST AT 12Z MONDAY TRACKING EASTWARD ALONG THE U.S./CANADIAN
BORDER. OVERALL MODELS ARE IN PRETTY GOOD AGREEMENT ON THE TRACK AND
SPEED OF THIS SHORTWAVE...WITH THE EXCEPTION OF THE 12.00Z NAM
WHICH BECOMES SLIGHTLY FASTER COME TUESDAY AND TUESDAY NIGHT. HAVE
DISCOUNTED THE NAM PROGRESSION AS AN OUTLIER FOR NOW. THE
PROGRESSIVE NATURE OF THE RIDGE AND SHORTWAVE RESULTS IN A VARIETY
OF ISSUES TO CONTEND WITH...
1. PRECIPITATION CHANCES AND TEMPERATURES MONDAY INTO MONDAY NIGHT.
A WARM FRONT AHEAD OF THE UPPER RIDGE AXIS IS FORECAST TO CROSS THE
AREA MONDAY NIGHT. PACIFIC MOISTURE MOVING THROUGH THE UPPER RIDGE
IN CONJUNCTION WITH ISENTROPIC LIFT AHEAD OF THIS WARM FRONT WILL
LIKELY TO LEAD TO EXTENSIVE MID AND HIGH CLOUDS. ADDITIONALLY...THE
LIFT APPEARS STRONG ENOUGH TO GENERATE PRECIPITATION FROM THESE
CLOUDS. THE BIG PROBLEM...THOUGH...IS LOW LEVEL DRY AIR LEFT OVER
FROM THE CURRENT CANADIAN HIGH PRESSURE AREA. OVERALL...12.00Z MODEL
GUIDANCE HAS BACKED OFF ON THE AMOUNT OF QPF POSSIBLE FROM THESE
CLOUDS...ESPECIALLY THE GFS...SUGGESTING THE DRY AIR MAY BE ABLE TO
ABSORB MUCH OF THE PRECIPITATION. HOWEVER...ALL GUIDANCE DOES
SUGGEST SOME LIGHT QPF POSSIBLE...THUS THE 20-40 PERCENT CHANCES
FROM THE PREVIOUS FORECAST STILL SEEMS REASONABLE. TIMING BETWEEN
18Z MONDAY TO 06Z TUESDAY ALSO STILL LOOKS GOOD. SHOULD SEE THE
CLOUDS AND PRECIPITATION PROGRESS EASTWARD THROUGH TIME DUE TO THE
PROGRESSION OF THE UPPER RIDGE. THE CLOUDS COMBINED WITH 850MB TEMPS
AT 18Z MONDAY OF 1C EAST TO 6C WEST ARE LIKELY TO KEEP TEMPERATURES
BELOW NORMAL...BUT NOT AS COLD AS TODAY.
2. HOW WARM TEMPERATURES WILL GET ON TUESDAY. THE SIGNAL OF A
CHINOOK WARM FRONT OFF THE ROCKIES...ACCOMPANYING THAT POTENT
SHORTWAVE...REMAINS FORECAST TO PUSH EAST THROUGH MUCH OF THE
FORECAST AREA DURING THE DAY TUESDAY. INCREDIBLY WARM 850MB TEMPS
FOR MID MAY ARE PROGGED TO FOLLOW IN ITS WAKE...WITH READINGS BY 00Z
OF 18-20C OVER CENTRAL WISCONSIN TO 22-24C WEST OF THE MISSISSIPPI
RIVER...OR 2 TO 3 STANDARD DEVIATIONS ABOVE NORMAL. SEEING THE
OBSERVED 850MB TEMPS UNDER THE UPPER RIDGE RIGHT NOW OVER THE
WESTERN U.S...THESE SEEM REASONABLE. THE QUESTION IS WITH A WARM
ADVECTION PATTERN THROUGH THE DAY...CAN WE MIX TO THESE 850MB TEMPS.
MODELS CONTINUE TO BE NOTORIOUSLY HIGH WITH SURFACE DEWPOINTS IN
THIS SITUATION...PREVENTING MODELS FROM MIXING ENOUGH. FOR
EXAMPLE...THE 12.00Z GFS/ECMWF/CANADIAN JUMP THEM OVER IOWA FROM
50-55 AT 12Z TO 60-65 AT 18Z...ALL LIKELY DUE TO EVAPOTRANSPIRATION
THAT IS NOT THERE YET. ADDITIONALLY...A DOWN-SLOPE FLOW FROM THE
ROCKIES USUALLY ENDS UP WITH DRIER DEWPOINTS...ESPECIALLY THIS TIME
OF YEAR. THUS...HAVE CONTINUED TO STAY TOWARDS THE WARM SIDE OF
GUIDANCE. ALTHOUGH THE 12.00Z NAM IS SLIGHTLY TOO PROGRESSIVE...ITS
TEMPERATURES SEEM REASONABLE. FOLLOWED MOS GUIDANCE MORE FOR
DEWPOINTS SINCE MOS HAS BEEN DOING MUCH BETTER IN THIS DEPARTMENT.
3. COLD FRONT CROSSING TUESDAY NIGHT AND POTENTIAL FOR PRECIPITATION
WITH IT. 12.00Z NAM AND GFS ARE JUST SLIGHTLY FARTHER SOUTH WITH THE
TRACK OF THE SHORTWAVE TRACKING ALONG THE CANADIAN BORDER...COMPARED
TO THE 12.00Z ECMWF/UKMET/CANADIAN. THIS DIFFERENCE RESULTS IN THE
NAM/GFS ADDING EXTRA FORCING TO THE LOW LEVEL FRONTOGENESIS ZONE ON
AND BEHIND THE COLD FRONT...AND THUS THE MODELS PRODUCE A BAND OF
PRECIPITATION OVER THE AREA. THE ECMWF/UKMET/CANADIAN ARE DRY. FEEL
THE LATTER MODEL GROUP IS MORE LIKELY TO OCCUR...BUT CONTINUED TO
HONOR THE NAM/GFS SCENARIO WITH A 20 PERCENT CHANCE JUST IN CASE.
WEDNESDAY INTO NEXT WEEKEND...
GOOD MODEL AGREEMENT EXISTS OF THE FLOW STARTING OFF AS ZONAL TO
BEGIN THIS PERIOD. ANY LOW LEVEL FRONTOGENETICAL FORCING BEHIND
TUESDAY NIGHTS COLD FRONT IS SOUTH OF THE AREA FOR WEDNESDAY...SO
WENT DRY DURING THIS TIME. THE ZONAL FLOW DOES NOT LAST LONG...WITH
A NEW TROUGH PROGGED TO COME INTO THE PACIFIC NORTHWEST THURSDAY
NIGHT. THIS CAUSES THE FLOW DOWNSTREAM TO BUCKLE...WITH THE 12.00Z
ECMWF/GFS/CANADIAN ALL SHOWING A SHORTWAVE TROUGH TRACKING ACROSS MN
AND WI THURSDAY INTO THURSDAY NIGHT. HAVE HONORED THE SHORTWAVE WITH
SOME SMALL CHANCES OF PRECIPITATION. WE COULD END UP WITH A DRY DAY
FRIDAY WITH SUBSIDENCE AND HIGH PRESSURE BUILDING IN. LOWERED
PRECIPITATION CHANCES FURTHER AND MAY BE ABLE TO COMPLETELY PULL
THEM WITH THE NEXT EXTENDED FORECAST UPDATE. THINGS LOOK TO PERHAPS
TO GET MORE ACTIVE FOR FRIDAY NIGHT INTO THE WEEKEND AS THE PACIFIC
NORTHWEST TROUGH BEGINS TO APPROACH THE PLAINS. SURPRISINGLY GOOD
MODEL AGREEMENT BETWEEN THE ECMWF AND GFS...ALONG WITH PREVIOUS
RUNS...OF A DEEPENING LOW DOWNSTREAM OVER NEBRASKA. AS ONE WOULD
EXPECT...A SURGE OF MOISTURE TRANSPORT OUT OF THE GULF OF MEXICO IS
AIMED DIRECTLY TOWARDS THE FORECAST AREA AHEAD OF THE LOW.
THUS...PRECIPITATION CHANCES INCREASE...ESPECIALLY ON SATURDAY WHERE
THE CONSENSUS EVEN RESULTS IN 50-60 PROBABILITIES. TEMPERATURES
SHOULD SLOWLY COOL THROUGH THE EXTENDED...BUT STILL STAY AT OR ABOVE
NORMAL WITH A FLOW GENERALLY OFF THE PACIFIC.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1146 AM CDT SUN MAY 12 2013
GENERALLY QUIET VFR CONDITIONS ACROSS THE TAF SITES THIS AFTERNOON
THROUGH MONDAY MORNING AS COOL CANADIAN HIGH PRESSURE DRIFTS EAST
ACROSS THE UPPER MIDWEST. CLOUDS THIS PERIOD LOOK LIMITED TO A FEW
HIGH-BASED DIURNAL CUMULUS THIS AFTERNOON THEN SCT CIRRUS LATE
TONIGHT/MON MORNING. DIURNAL WARMING/MIXING TO PRODUCE NORTHWEST
WINDS 10-15KTS G20KTS THIS AFTERNOON...BECOMING LGT/VARIABLE AS THE
SFC RIDGE AXIS DRIFTS OVERHEAD TONIGHT...THEN SOUTH TO SOUTHWEST 8-
14KT ON THE BACK SIDE OF THE HIGH ON MONDAY. MON AFTERNOON WILL SEE
AN INCREASE OF MID LEVEL MOISTURE/CLOUDS AND A SMALL SHRA CHANCE AT
THE TAF SITES.
&&
.FIRE WEATHER...TUESDAY
ISSUED AT 320 AM CDT SUN MAY 12 2013
AFTER HAVING BREEZY...DRYING AND UNSEASONABLY COOL WEATHER THIS
WEEKEND...INCLUDING FROST/FREEZE CONDITIONS TONIGHT ACROSS
WISCONSIN...CONCERN CONTINUES TO INCREASE ABOUT CRITICAL FIRE
WEATHER CONDITIONS ON TUESDAY. MOST LOCATIONS SHOULD SEE HIGHS
CLIMB INTO THE 80S...WITH SOME WEST OF THE MISSISSIPPI RIVER
REACHING 90. DEWPOINT FORECASTS REMAIN TRICKY...BUT MINIMUM
RELATIVE HUMIDITY VALUES SHOULD HAVE NO PROBLEM FALLING INTO THE
30 TO 40 PERCENT RANGE. IT IS POSSIBLE LOCATIONS SAY ALONG AND
WEST OF US-52 COULD END UP DROPPING TOWARDS 25 PERCENT. COMBINED
WITH SOUTHWEST WINDS OF 15 TO 20 MPH AND HIGHER GUSTS...THE
SITUATION BEARS WATCHING.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ032-041-
054- 061.
FREEZE WARNING FROM 1 AM TO 7 AM CDT MONDAY FOR WIZ017-029-
033-034-042>044-053-055.
MN...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR MNZ079-088-
096.
IA...FROST ADVISORY FROM 1 AM TO 7 AM CDT MONDAY FOR IAZ011-030.
&&
$$
UPDATE.........RRS
SHORT TERM.....AJ
LONG TERM......AJ
AVIATION.......RRS
FIRE WEATHER...AJ