Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/25/12
AREA FORECAST DISCUSSION
NWS TUCSON AZ
255 PM MST MON APR 23 2012
.SYNOPSIS...HIGH PRESSURE WILL WEAKEN AND RESULT IN SLIGHTLY COOLER
TEMPERATURES THROUGH THURSDAY. A LOW PRESSURE SYSTEM WILL TRACK
THROUGH THE GREAT BASIN ON THURSDAY BRINGING COOLER
TEMPERATURES...BREEZY TO WINDY CONDITIONS AND SCATTERED SHOWERS.
THEREAFTER...DRY NORTHWESTERLY FLOW WILL KEEP DAYTIME TEMPERATURES
RIGHT AROUND NORMAL.
&&
.DISCUSSION...LATEST WATER VAPOR SATELLITE IMAGERY SHOWS SHORTWAVE
MOVING ACROSS NORTHERN BAJA INTO SOUTHERN CALI/SOUTHEAST AZ. PRECIP
WATERS AROUND HALF AN INCH MIXING WITH A VERY UNSTABLE AIRMASS HAS
ALLOWED AFTERNOON BUILDUPS ACROSS MUCH OF SOUTHEAST ARIZONA AND
ALONG THE MOGOLLON RIM. A FEW LIGHTNING STRIKES HAVE BEEN OBSERVED
ACROSS EXTREME NORTHWEST CHIHUAHUA AND WESTERN NEW MEXICO...BUT
CURRENTLY NO STRIKES IN SOUTHEAST ARIZONA. LATEST HRRR SOLUTION
SUPPORTS CURRENT THINKING OF SOME ENHANCEMENT OF CLOUD COVER AS
SHORTWAVE APPROACHES BUT STILL ONLY A SLIGHT CHANCE OF CONVECTION.
SO FAR RADAR REMAINS ECHO FREE. INCREASING SOUTHWEST WINDS HAVE
ALLOWED STRONG MIXING AGAIN THIS AFTERNOON WITH TUCSON RETURNING TO
THE CENTURY MARK BREAKING THE MAX TEMPERATURE RECORD FOR TODAY.
HIGH PRESSURE PROGGED TO WEAKEN THE NEXT SEVERAL DAYS AS AN AREA OF
LOW PRESSURE APPROACHES THE WESTERN COAST. THIS WILL RESULT IN A
SLIGHT BREAK IN THE HEAT WITH VALLEY TEMPERATURES RETURNING TO THE
UPPER 80S/LOW 90S...STILL A FEW DEGREES ABOVE NORMAL.
SOME MODEL DISAGREEMENT STILL EXISTS WITH APPROACHING SYSTEM.
NAM/SREF/DGEX SOLUTIONS BRING UPPER LEVEL LOW ONSHORE ABOUT 6 HOURS
EARLIER THAN GFS/EUROPEAN SOLUTIONS...WITH THE UKMET BEING EVEN
SLOWER THAN THE GFS/EURO. AS A RESULT...NAM/SREF/DGEX SOLUTIONS
BRING COLD FRONT THROUGH SOUTHERN ARIZONA WITH ASSOCIATED PRECIP 6
TO 12 HOURS EARLIER THAN GFS/EURO SOLUTIONS. BASED ON RUN TO RUN
CONTINUITY AND PAST PERFORMANCE...HAVE TRENDED FORECAST TO MORE OF A
GFS/EUROPEAN BLEND. POSITIONING AND TRAJECTORY OF THE LOW WILL TAP
ABUNDANT MOISTURE...PRECIP WATERS IN EXCESS OF ONE INCH...IN THE
PACIFIC AND RESULT IN GOOD MOISTURE ADVECTION ACROSS THE REGION.
SHOWERS SHOULD START ALONG THE COLD FRONT ACROSS THE WESTERN DESERTS
WEDNESDAY NIGHT/THURSDAY MORNING AND PUSH NORTHEAST. BEST MOISTURE
SOURCE WILL REMAIN NORTH OF THE AREA WITH PRECIP WATERS IN PHOENIX
REACHING UP TO AN INCH AND A QUARTER...WHILE TUCSON WILL BE AROUND
ONE INCH. DOUGLAS PRECIP WATERS WILL BE ONLY AROUND HALF AN INCH.
SHOWERS WILL BE MOSTLY TIED TO THE FRONT ACROSS SOUTHERN
ARIZONA...SO EXPECT ONLY AN HOUR OR TWO OF PRECIP AS THE FRONT
QUICKLY PUSHES THROUGH THURSDAY LATE MORNING/EARLY AFTERNOON.
MOISTURE WILL BE LIMITED ACROSS EXTREME SOUTHEAST ARIZONA...SO ITS
POSSIBLE LOCATIONS ALONG THE INTERNATIONAL BORDER MAY BE LEFT OUT OF
THIS EVENT. THUNDERSTORM DEVELOPMENT WILL BE POSSIBLE ALONG THE
FRONT DUE TO ADDITIONAL LIFT IN AN UNSTABLE AND MOIST AIRMASS. GOOD
UPSLOPE FLOW WILL ALSO ENHANCE ANY PRECIP ACROSS THE HIGHER TERRAIN.
RAISED POPS TO SCATTERED CATEGORY...BUT WILL PROBABLY NEED TO
FURTHER RAISE POPS ONCE MODELS COME INTO BETTER AGREEMENT. STRONG
SOUTHWEST WINDS WILL ALSO PERSIST IN ADVANCE OF THE FRONT WITH
BREEZY TO WINDY CONDITIONS POSSIBLE TUCSON EWD. TEMPERATURES
THURSDAY WILL RANGE FROM THE UPPER 70S/LOW 80S IN THE VALLEYS
THURSDAY DUE TO CLOUD COVER AND PRECIP BUT WILL QUICKLY REBOUND
FRIDAY.
DRY NORTHWESTERLY FLOW WILL USHER IN BEHIND THE STORM SYSTEM
ALLOWING TEMPERATURES TO RETURN TO SLIGHTLY ABOVE NORMAL...BUT NOT
BACK TO THE HIGH TEMPERATURES WE HAVE SEEN THE PAST SEVERAL
DAYS.
&&
.AVIATION...MID LEVEL MOISTURE ACROSS THE EASTERN HALF OF SOUTHEAST
ARIZONA WILL RESULT IN A FEW AFTERNOON BUILDUPS TODAY AND TUESDAY.
FROM KTUS EASTWARD EXPECT SCT CLOUDS AT 8-11K FT AGL...AND SCT-BKN
CLOUDS AOA 20K FT AGL THRU 24/04Z...THEN AFT 24/04Z FEW-SCT CLOUDS
AOA 20K FT AGL. FROM KTUS WESTWARD...EXPECT SCT-BKN CLOUDS AOA 20K
FT AGL THRU 24/02Z...THEN SKC CONDITIONS. SLY/SWLY SURFACE WIND AT
10-15 KTS WITH GUSTS TO AROUND 25 KTS THRU 24/03Z...WITH STRONGEST
WINDS EAST OF KTUS...THEN SURFACE WIND GENERALLY LESS THAN 10 KTS
THRU 24/15Z. SWLY/WLY SURFACE WIND AT 8-13 KTS WITH GUSTS TO AROUND
22 KTS LATE TUESDAY MORNING AND TUESDAY AFTERNOON. AVIATION
DISCUSSION NOT UPDATED FOR TAF AMENDMENTS.
&&
.FIRE WEATHER...DRY CONDITIONS AND ABOVE NORMAL TEMPERATURES WILL
CONTINUE THROUGH WEDNESDAY. A FEW AFTERNOON AND EARLY EVENING
BUILDUPS WILL BE POSSIBLE OVER THE EASTERN HALF OF SOUTHEAST ARIZONA
TODAY AND TUESDAY...WITH THE POSSIBILITY OF A DRY LIGHTNING STRIKE
OR TWO. ALSO EXPECT SOME AFTERNOON AND EARLY EVENING BREEZES TODAY
AND TUESDAY. A STRONG STORM SYSTEM WILL THEN APPROACH THE REGION ON
WEDNESDAY...RESULTING IN STRONG AND GUSTY WINDS. THIS SYSTEM WILL
MOVE ACROSS THE STATE ON THURSDAY...WITH MUCH COOLER TEMPERATURES
AND A CHANCE OF SHOWERS.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...NONE.
$$
MINNICK
WEATHER.GOV/TUCSON
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1125 AM MDT MON APR 23 2012
.UPDATE...
ISSUED AT 1124 AM MDT MON APR 23 2012
HAVE MADE SOME MINOR ADJUSTMENTS TO POPS FIELD TO FIT CURRENT
TRENDS IN BOTH THE HRRR-3KM AND RUC13 MODELS. CURRENT CU FIELD
BUILDING OVER THE HIGH COUNTRY THIS MORNING AND INCREASING HEAT
AND INSTABILITY WILL ALLOW A FEW HIGH BASED STORMS TO DEVELOP
LATER TODAY. FOCUS WILL BE ACROSS THE SAN JUAN MOUNTAINS. HOURLY
POP GRIDS HAVE BEEN UPDATED AND NEW POINT AND CLICK FORECASTS WILL
REFLECT THESE ADJUSTMENTS. MAIN ZONE PACKAGE WILL NOT BE UPDATED
ATTM.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 322 AM MDT MON APR 23 2012
A HUGE RIDGE WILL DOMINATE THE WEATHER OVER THE WESTERN U.S. FOR
THE NEXT SEVERAL DAYS. THE MAIN MESSAGE FOR TODAY WILL BE NEAR
RECORD TO RECORD HIGH TEMPERATURES AGAIN TODAY. 700 MB TEMPS
CONTINUE TO RISE...REACHING PLUS 10 TO 12 DEGREES LATE THIS
AFTERNOON. THIS MORNING A STRING OF WEAK VORT MAXES FLOWING
BENEATH DIVERGENCE ALOFT WILL PRODUCE A STRONG OF SHOWERS
EXTENDING ACROSS SRN ID AND SW WY WITH A LINE OF MID AND HI CLOUDS
RIDING OVER THE CREST OF THE RIDGE AND INTO NE UT AND WRN CO. THE
TRAJECTORY OF THE VORT MAXES SHOULD TAKE THEM NORTH AND NORTHEAST
INTO ID AND WY...SO BELIEVE ON THESE WILL NO AFFECT THE FORECAST
AREA.
THE FIRST IN A SERIES SMALLISH WAVES WILL AFFECT THE AREA LATE
TONIGHT INTO TUE MORNING AS THE UPPER RIDGE BEGINS TO SLIDE EAST
AND DE-AMPLIFY. THIS FIRST WAVE WAS CURRENTLY SOUTHWEST OF SRN CA
AND IS EXPECTED TO REACH THE 4 CORNERS BY 12Z TUE BUT WILL BE
WEAKENING AS IT ENCOUNTERS THE RIDGE...BUT COULD STILL GENERATE
SOME ISOLATED SHOWER OR THUNDERSTORM THROUGH TUE MORNING. BOTH
NAM/GFS HAVE IT CROSSING WRN CO MIDDAY TUE. MOISTURE NOT
GREAT...BUT ENOUGH MID-LEVEL MOISTURE LIKELY TO BE PRESENT FOR
ISOLATED TO SCATTERED SHOWERS/THUNDERSTORMS TUE AFTERNOON. ACTUAL
PRECIPITATION AT THE SURFACE LOOKS TO BE LITTLE OR NONE...HOWEVER.
MAIN STORY TUESDAY WILL BE THE ADDITION OF A LITTLE MORE WIND TO THE
CONTINUED MUCH ABOVE NORMAL TEMPS AND LOW DAYTIME HUMIDITIES. DEEP
MIXING FROM DAYTIME HEATING AND SOME STRENGTHENING OF THE SW FLOW
BEHIND THE RIDGE AXIS SHOULD LEAD TO SOME GUSTY WINDS TUE AFTERNOON
ESPECIALLY FROM NW CO TO NRN SAN JUAN COUNTY UTAH. THE FIRE WEATHER
WATCH FOR PORTIONS OF NW CO AND NE UT STILL STILL LOOKS ON TRACK.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 322 AM MDT MON APR 23 2012
TUESDAY NIGHT-WEDNESDAY NIGHT: SOME BRIEF DRYING INDICATED IN THE
700-500 MB LAYER SPECIFIC HUMIDITY TUE EVENING BEHIND THAT FIRST
WAVE...BUT THE GENERAL TREND STILL LOOKS TO BE GRADUALLY INCREASING
MOISTURE FOR WED. ANOTHER UPPER WAVE PASSES TUE NIGHT THAT COULD
KEEP ISOLATED SHOWERS PRESENT AND MAY COOL THINGS A FEW DEGREES ON
WED. CLOUDS ON THE INCREASE FROM THE SOUTHWEST WED NIGHT AS A MORE
SIGNIFICANT UPPER TROUGH APPROACHES.
BY THURSDAY MORNING THE MAIN PACIFIC TROUGH WILL BE MOVING
ONSHORE AND THE NAM12 SHOWS A STRONG SHORTWAVE TROUGH EJECTING
TROUGH SRN CA AND NW AZ...THEN REACHING THE FOUR CORNERS BY NOON.
THE GFS SHOWS THIS TROUGH MUCH STRONGER AND CLOSED OFF OVER SRN CA
THU MORNING. IT MOVES THIS FEATURE MORE SLOWLY THRU AZ AND KEEPS
IT CLOSED AS IT MOVES INTO WESTERN NM LATE THU AFTERNOON. THE
CONSENSUS IN THE MODELS CALLS FOR INCREASING CLOUDS...A BETTER
CHANCE OF PRECIPITATION AND COOLER TEMPS THU. THE BEST CHANCE OF
PRECIP SHOULD BE LATE THU AFTERNOON THRU THU NIGHT. MODEL
SOLUTIONS FOR FRIDAY HAVE THE MAIN TROUGH LINE EAST OF THE AREA...
WITH NW WINDS AND COOL ADVECTION OVER WRN CO AND ERN UT. SAT AND
SUN LOOK LIKE RELATIVELY DRY NORTHWEST FLOW OVER THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1107 AM MDT MON APR 23 2012
VFR CONDITIONS WILL PREVAIL ACROSS THE FORECAST AREA. ISOLATED
HIGH-BASED THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS THIS
AFTERNOON AND DRIFT ACROSS THE HIGHER VALLEYS THIS EVENING. LITTLE
OR NO RAIN WILL REACH THE GROUND WITH THESE STORMS...ALTHOUGH GUSTY
OUTFLOW WINDS TO NEAR 50 MPH WILL BE POSSIBLE.
&&
.FIRE WEATHER...
ISSUED AT 322 AM MDT MON APR 23 2012
RECORD TO NEAR RECORD WARMTH WILL CONTINUE TODAY THROUGH TUESDAY.
AFTERNOON HUMIDITY WILL DROP TO THE LOWER TEENS AND SINGLE DIGITS
OVER MANY VALLEY LOCATIONS MONDAY AND TUESDAY. VERTICAL MIXING
WILL BE STRONG...LEADING TO GUSTY AFTERNOON WINDS...STRONGER NEAR
HIGH-BASED THUNDERSTORMS THAT ARE POSSIBLE OVER RIDGES THIS
AFTERNOON. AREAL COVERAGE OF THUNDERSTORMS AND BRIEF WIND GUSTS
WILL LIMIT CRITICAL FIRE WEATHER CONDITIONS TODAY. ON TUESDAY
HOWEVER...WINDS ALOFT WILL INCREASE AND THE CHANCE OF SUSTAINED
WINDS AND GUSTS OVER 25 MPH WILL INCREASE. BECAUSE OF THIS...A
FIRE WEATHER WATCH HAS BEEN CONTINUED FOR CO FIRE ZONES 200 AND
202 AND UT FIRE ZONE 444 FOR CRITICAL FUELS...GUSTY WINDS...AND
LOW HUMIDITIES. COOLER AND MORE MOIST CONDITIONS CAN BE EXPECTED
THROUGH LATE WEEK AS PRECIPITATION CHANCES ALSO INCREASE.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR COZ200-202.
UT...FIRE WEATHER WATCH FROM TUESDAY AFTERNOON THROUGH TUESDAY
EVENING FOR UTZ444.
&&
$$
UPDATE...JDC
SHORT TERM...CJC/JAD
LONG TERM...JAD/CJC
AVIATION...JDC
FIRE WEATHER...CC
AREA FORECAST DISCUSSION
NWS DENVER CO
925 AM MDT MON APR 23 2012
.UPDATE...CURRENT FORECAST ON TRACK. ENOUGH MOISTURE ACROSS
MOUNTAINS AND FOOTHILLS FOR PERHAPS A FEW SHOWERS OR STORMS THIS
AFTERNOON AND EVENING WITH THE BEST CHANCE ALONG THE FOOTHILLS OF
BOULDER AND JEFFERSON COUNTIES WHERE LATEST RUC SHOWS CAPES
INCHING TOWARD 500 J/KG. FORECAST SOUNDINGS SHOW INVERTED-V TYPE
PROFILE...SO THE ACTIVITY HAS THE POTENTIAL TO PRODUCE GUSTY
WINDS...IF THERE IS DEVELOPMENT. OTHERWISE DRY AND WARM CONDITIONS
WILL PREVAIL.
&&
.AVIATION...CURRENT TAF TRENDS LOOK ON TRACK. ANY SHOWERS OR
STORMS THAT DO DEVELOP THIS AFTERNOON WILL BE WEST OF THE DENVER
AREA...SHOULD NOT AFFECT THE AIRPORTS.
&&
.HYDROLOGY...SLIGHT CHANCE FOR SHOWERS OR STORMS OVER THE
MOUNTAINS AND FOOTHILLS THIS AFTERNOON AND EVENING. IF THE
ACTIVITY DOES DEVELOP...RAINFALL WILL BE LESS THAN A TENTH OF AN
INCH.
&&
.PREV DISCUSSION... /ISSUED 420 AM MDT MON APR 23 2012/
SHORT TERM...A WEAK NORTHWEST FLOW ALOFT WILL PREVAIL TODAY AS
THE CENTER OF AN UPPER LEVEL RESIDES OVER UTAH AND WESTERN
COLORADO. WARMER AIR WILL MOVE INTO THE AIR TODAY WITH HIGHS
CLIMBING ABOVE 80 DEGREES ACROSS MOST OF NORTHEAST COLORADO. SKIES
WILL START OFF CLEAR THIS MORNING. AS THE AIRMASS DESTABILIZES OVER
THE MOUNTAINS...CUMULUS CLOUDS WILL FORM. SLIGHT CHANCE FOR ENOUGH
MOISTURE AND INSTABILITY TO PRODUCE A FEW WEAK SHOWERS OR
THUNDERSTORMS OVER THE HIGHER TERRAIN. FOR THE FRONT RANGE AND
EASTWARD...AIRMASS WILL BE TOO DRY AND STABLE FOR ANY SHOWERS OR
THUNDERSTORMS.
LONG TERM...HIGH AMPLITUDE WAVE PATTERN OVER NORTH AMERICA DURING
THE FIRST HALF OF THE WEEK BREAKS DOWN ALLOWING A LONGWAVE UPPER
LEVEL TROUGH TO MOVE OVER WEST COAST LATE ON WEDNESDAY ACCORDING
TO A CONSENSUS OF THE MODELS...AND EVENTUALLY OVER THE CENTRAL
ROCKY MTN REGION BY LATE IN THE DAY THURSDAY AND FRIDAY. 582
DECAMETER HEIGHTS ASSOCIATED WITH THE BROAD UPPER RIDGE OVER
COLORADO ON TUESDAY WILL LIKELY RESULT IN NEAR RECORD
TEMPERATURES...AND POSSIBLY RECORD BREAKING TEMPERATURES. HOWEVER
MID-LEVEL MOISTURE TRAPPED WITHIN THIS RIDGE COUPLED WITH STEEP
LAPSE RATES GENERATED BY VERY WARM BNDRY LAYER TEMPERATURES COULD
SPAWN ISOLATED TO SCATTERED SHOWERS/T-STORMS OVER AND NEAR THE
MOUNTAINS AND FRONT RANGE FOOTHILLS LATE IN THE DAY TUESDAY.
CONVECTION MOVED OFF THE HIGH TERRAIN BY LIGHT WESTERLY TRANSPORT
WINDS WILL PROBABLY GENERATE MORE WIND THAN RAINFALL OVER THE
ADJACENT PLAINS. HENCE THE LOW PRECIP CHANCES IN THIS AREA.
BY WEDNESDAY MODELS SHOW THE UPPER RIDGE WEAKENING SOME AS IT
CONTINUES TO DRIFT EASTWARD OVER THE CENTRAL AND SOUTHERN GREAT
PLAINS. TEMPERATURES STILL QUITE WARM ON WEDNESDAY BUT WITH
COOLING ALOFT AND AN INCREASE IN CLOUD COVER...HIGH TEMPERATURES
ARE EXPECTED TO BE 2-3C COOLER THAN THE DAY BEFORE. AN INCREASE
IN MOISTURE BOTH AT THE SFC AND ALOFT COUPLED WITH STRONG DIABATIC
HEATING IS EXPECTED TO GENERATE A BIT MORE CONVECTION/THUNDERSTORM
ACTIVITY/AREAWIDE. STILL PRECIPITATION LOOKS TO BE ON THE LIGHT
SIDE.
BY THURSDAY...MEDIUM RANGE MODELS GENERALLY SHOW THE UPPER TROUGH
WITH A CLOSED 500MB LOW PASSING OVER THE FOUR CORNERS AREA DURING
THE DAY THURSDAY...THEN SWINGING OUT OVER THE ERN PLAINS OF
COLORADO SOMETIME THURSDAY NIGHT OR EARLY FRIDAY MORNING. THIS
WOULD SET THE STAGE FOR A 24-36 HOUR PD OF COOLER AND UNSETTLED
WEATHER FOR THE CWA. PRIOR TO TROUGH PASSAGE...STIFF SOUTHEASTERLY
FLOW ON THURSDAY USHER IN 50-60F DEWPT TEMPS ON THE PLAINS
ACCORDING TO THE GFS WHICH MODEL SOUNDINGS INDICATE AFTERNOON/
EARLY EVENING CAPE VALUES WELL OVER A 1000 J/KG ACROSS THE
NORTHEAST CORNER OF THE STATE. COULD SEE ISOLATED SUPERCELLS OUT
THERE PRODUCING SEVERE WX...INCLUDING LARGE HAIL.
TROUGH SLOWLY MOVES OUT BY THE WEEKEND. HOWEVER WITH LINGERING
INSTABILITY AND MOISTURE WILL NEED TO HOLD ONTO AT LEAST A SLIGHT
CHANCE OF AFTERNOON AND EVENING SHOWERS/T-STORMS THROUGH SUNDAY.
SHOULD ALSO SEE A GRADUAL WARMUP OVER THE WEEKEND.
AVIATION...AN UPPER LEVEL RIDGE MOVING INTO COLORADO TODAY WILL
BRINGING MOSTLY CLEAR SKIES AND LIGHT WINDS TODAY AND TONIGHT. MAY
BE ENOUGH MOISTURE AND INSTABILITY TO SQUEEZE OUT A FEW WEAK
SHOWERS OR THUNDERSTORMS OVER THE HIGH COUNTRY WEST OF DENVER.
THE DENVER AREA AND EASTWARD WILL BE TOO DRY AND STABLE FOR ANY
SHOWERS OR THUNDERSTORMS.
HYDROLOGY...A FEW WEAK SHOWERS OR THUNDERSTORMS WILL BE POSSIBLE
OVER THE MOUNTAINS AND FOOTHILLS THIS AFTERNOON AND EVENING. IF
ANY ACTIVITY FORMS...IT WILL BE LIGHT AND SHORT LIVED.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....BAKER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
909 PM EDT TUE APR 24 2012
.UPDATE (TONIGHT THROUGH WEDNESDAY)...
00Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW A HIGHLY
AMPLIFIED UPPER LEVEL PATTERN OVER NORTH AMERICA. NORTHERN STREAM
FLOW RIDGES FAR TO THE NORTH OVER THE WESTERN/CENTRAL STATES BEFORE
DIVING BACK TO THE SOUTHEAST INTO LONGWAVE AND SHARP TROUGHING OVER
THE EASTERN SEABOARD. THIS TROUGH IS ANCHORED BY A DEEP 524DM H5 LOW
SPINNING OVER EASTERN ONTARIO/WESTERN QUEBEC. CLOSER TO HOME...THE
AXIS OF THE EASTERN TROUGH IS PULLING AWAY TO THE NORTH AND EAST
ALLOWING HEIGHTS TO RISE. THESE HEIGHT RISES WILL CONTINUE BACK
TOWARD MORE SEASONABLE LEVELS THROUGH THE NEXT 24 HOURS. 25/00Z KTBW
SOUNDING PROFILE SHOWS A VERY DRY ATMOSPHERIC COLUMN IN PLACE OVER
THE FORECAST AREA WITH A PW VALUE DOWN TO AROUND 0.35". THIS VALUE
IS ONLY AROUND 35% OF CLIMATOLOGY FOR LATE APRIL. THE DRY COLUMN AND
LACK OF SYNOPTIC FORCING IS ALSO HELPING TO KEEP OUR SKIES VIRTUALLY
CLOUD FREE THIS EVENING. THESE CLEAR SKIES WILL LINGER THROUGH THE
OVERNIGHT.
AT THE SURFACE...GRADIENT IS RELAXING OVER THE PENINSULA AS 1020MB
HIGH PRESSURE APPROACHES FROM THE WEST. THIS RIDGE AXIS WILL SETTLE
OVER THE CENTRAL/SOUTHERN PORTION OF THE PENINSULA OVERNIGHT AND
THEN REMAIN IN PLACE THROUGH THE DAYLIGHT HOURS OF WEDNESDAY.
ALL THIS LEADS TO A FAIRLY BENIGN FORECAST. OTHER THAN SOME
ABNORMALLY COLD TEMPERATURES FOR LATE APRIL TONIGHT...AND FIRE
WEATHER CONCERNS WEDNESDAY AFTERNOON...NO OTHER SIGNIFICANT SENSIBLE
WEATHER IS EXPECTED. THE RELAXING GRADIENT HAS ENDED ANY HEADLINES
OVER THE MARINE AREA...AND WINDS AND SEAS WILL FURTHER DIMINISH INTO
THE MIDDLE OF THE WEEK.
IN GENERAL WE ARE EXPECTING TEMPERATURES TO BE SIMILAR IN NATURE TO
WHAT WAS OBSERVED MONDAY NIGHT. WHILE THE OVERALL LOW LEVEL COLUMN
HAS RECOVERED SOMEWHAT DURING THE DAYLIGHT HOURS OF TUESDAY...THE
CLOSE PROXIMITY OF THE HIGH CENTER WILL ALLOW FOR MORE WIDESPREAD
BOUNDARY LAYER DECOUPLING/MORE EFFICIENT RADIATIONAL COOLING
PROCESSES. EXPECTING WIDESPREAD TEMPERATURES AWAY FROM THE COAST TO
DROP INTO THE 40S...WITH A FEW NORMALLY COLDER SPOTS UNDER
RADIATIONAL COOLING DIPPING BRIEFLY INTO THE UPPER 30S AROUND
SUNRISE. WITH ABUNDANT SUNSHINE TEMPS WILL RESPOND QUICKLY ON
WEDNESDAY AND LOOKING FOR TEMPERATURES TO REBOUND BACK INTO THE
UPPER 70S/LOWER 80S AWAY FROM THE COAST. HAVE SEEN A DECENT DROP IN
THE SURFACE SHELF WATER TEMPS THE PAST FEW DAYS...AND THIS WILL
LIKELY LEAD TO EFFICIENT SEA-BREEZE FORMATION WEDNESDAY AFTERNOON.
THIS FLOW OFF THE SHELF WATERS SHOULD HELP KEEP TEMPS IN THE
LOWER/MID 70S AT THE BEACHES.
&&
.AVIATION...
VFR NEXT 24 HOURS. WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT
THEN LOCAL BAY AND SEA BREEZES AT 7 TO 12 KNOTS WEDNESDAY AFTERNOON.
&&
.MARINE...
HIGH PRESSURE BUILDING IN THE CENTRAL GULF THE NEXT FEW DAYS WILL
ALLOW FOR WINDS AND SEAS TO DIMINISH AND REMAIN LOW THROUGH THE END
OF THE WEEK. INCREASING RAIN CHANCES OVER THE WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 55 78 63 83 / 0 0 0 0
FMY 53 84 60 87 / 0 0 0 0
GIF 48 83 60 87 / 0 0 0 0
SRQ 54 79 60 81 / 0 0 0 0
BKV 44 81 52 84 / 0 0 0 0
SPG 60 77 66 80 / 0 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...FIRE WEATHER WATCH FROM WEDNESDAY AFTERNOON THROUGH
WEDNESDAY EVENING FOR CHARLOTTE-DE SOTO-HARDEE-
HIGHLANDS-HILLSBOROUGH-LEE-MANATEE-POLK-SARASOTA-
SUMTER.
GULF WATERS...NONE.
&&
$$
UPDATE...14/MROCZKA
AVIATION...63/JILLSON
AREA FORECAST DISCUSSION
NWS MIAMI FL
144 AM EDT MON APR 23 2012
.AVIATION...
WESTERLY TO NORTHWESTERLY FLOW IN THE 10 TO 15 KNOT RANGE WITH
GUSTS TO NEAR 24 KNOTS POSSIBLE WILL CONTINUE ACROSS THE REGION
THROUGH MOST THE FORECAST PERIOD. VFR CONDITIONS EXPECTED TO
PREVAIL THROUGH FORECAST PERIOD WITH LITTLE CHANCE OF PRECIP
EXCEPT FOR TERMINAL KAPF WHERE A FEW LIGHT SHOWERS MAY COME OFF
ADJACENT GULF WATERS FROM TIME TO TIME.
60
&&
.PREV DISCUSSION... /ISSUED 1038 PM EDT SUN APR 22 2012/
UPDATE...WINDS OVER LAKE OKEECHOBEE CONTINUE AROUND 20 KT WITH
GUSTS TO AROUND 25 KT...SO EXTENDED THE SCA FOR THE LAKE UNTIL 6
AM MON. OTHERWISE, NO CHANGES TO THE FORECAST ARE NEEDED THIS
EVENING. HIGH PRESSURE WILL CONTINUE TO BUILD INTO FLORIDA FROM
THE NORTHWEST, RESULTING IN RATHER COOL AND DRY CONDITIONS OVER
THE NEXT FEW DAYS. /GREGORIA
PREV DISCUSSION... /ISSUED 734 PM EDT SUN APR 22 2012/
AVIATION...
REMNANT PRECIPITATION ASSOCIATED WITH THE DEPARTED UPPER LEVEL
SYSTEM IS ALL BUT GONE FROM THE SOUTH FLORIDA AREA. ONLY A FEW
SPRINKLES REMAIN AROUND KPBI BUT SHOULD MOVE ON QUICKLY. THE ONLY
FACTOR THROUGH THIS TAF PERIOD WILL BE THE GUSTY WESTERLY GRADIENT
WINDS IN THE WAKE OF THIS SYSTEM. WINDS SHOULD REMAIN GUSTY
THROUGH THE OVERNIGHT HOURS AT ALL SITES.
PREV DISCUSSION... /ISSUED 649 PM EDT SUN APR 22 2012/
UPDATE...WINDS HAVE SUBSIDED SO THE WIND ADVISORY WAS CANCELLED.
JUST A FEW SMALL SHOWERS NEAR LAKE OKEECHOBEE. WILL UPDATE
FORECAST SOON TO TAKE OUT MENTION OF SHOWERS AS COOLER AND DRIER
AIR WILL CONTINUE TO MOVE INTO SOUTH FL TONIGHT. FOR ADDITIONAL
FORECAST DETAILS, SEE PREVIOUS DISCUSSION BELOW.
PREV DISCUSSION... /ISSUED 307 PM EDT SUN APR 22 2012/
DISCUSSION...
COLD FRONT MOVING THROUGH SOUTH FLORIDA THIS AFTERNOON. ALMOST ALL
SHOWERS THAT MOVED ACROSS THE REGION PRODUCED GUSTS OF 35-45
MPH...WITH ONE LONE THUNDERSTORM PRODUCING WINDS TO 54 MPH AT
KFXE. ONLY A FEW LINGERING SHOWERS WERE ACROSS THE EAST COAST
METRO AREAS AND THESE SHOULD END OVER THE NEXT HOUR OR TWO. STRONG
WESTERLY WINDS WILL CONTINUE...HOWEVER...ACROSS BROWARD...MIAMI
DADE...MAINLAND MONROE AND COASTAL COLLIER COUNTIES AND FREQUENT
GUSTS TO 40 MPH ARE EXPECTED THROUGH EARLY THIS EVENING. SO THE
WIND ADVISORY WILL REMAIN IN EFFECT THROUGH 8 PM THIS EVENING.
WATER VAPOR AND RUC ANALYSIS THIS AFTERNOON SHOWED SURFACE HIGH
PRESSURE NEAR THE NORTH CAROLINA COAST RACING OFF TO THE
NORTHEAST. AN UPPER LEVEL TROUGH AND CUTOFF UPPER LOW WERE DIGGING
SOUTHEAST ACROSS KENTUCKY THIS AFTERNOON. DRIER AIR IS EXPECTED TO
BEGIN FILTERING INTO THE REGION STARTING AROUND MIDNIGHT BEHIND
THE FRONT...WITH PWATS FALLING BELOW 0.75 INCHES. BREEZY
CONDITIONS WILL CONTINUE THROUGH THE EVENING FOR MUCH OF THE
REGION AND INTO THE OVERNIGHT HOURS FOR AREAS ALONG THE COAST.
COOLER CONDITIONS ARE EXPECTED TONIGHT WITH LOWS IN THE 50S AROUND
THE LAKE TO THE LOW TO MID 60S FOR THE EAST COAST METRO AREAS.
A SECONDARY SURGE OF DRIER AND COOLER AIR IS EXPECTED ON MONDAY AS
THE STRONG TROUGH OF LOW PRESSURE DIGS INTO THE SOUTHEAST AND
FLORIDA. THIS WILL INCREASE THE WINDS ACROSS THE REGION MONDAY
AFTERNOON...AND BREEZY TO WINDY CONDITIONS CAN BE EXPECTED...
ESPECIALLY TOWARDS THE GULF COAST. TEMPERATURES ON MONDAY WILL
RISE INTO THE UPPER 70S TO LOWER 80S.
MUCH COOLER AND EVEN DRIER AIR WILL BEGIN TO FILTER INTO THE
REGION...WITH PWATS FALLING BELOW 0.5 INCHES BY TUESDAY MORNING.
LOWS AND HIGHS TUESDAY THROUGH WEDNESDAY ARE EXPECTED TO BE 7-12
DEGREES BELOW NORMAL. 1000-850MB THICKNESS VALUES TUESDAY MORNING
ARE EXPECTED TO BE AROUND 1340M. SO TEMPERATURES MAY FALL INTO THE
MID/UPPER 40S NEAR THE LAKE...NEAR 50 ACROSS THE REST OF THE
INTERIOR...AND 50S TO AROUND 60 FOR THE EAST COAST METRO AREAS.
HIGHS ON TUESDAY ARE EXPECTED TO ONLY GET INTO THE LOW TO MID 70S
ACROSS THE REGION. FOR WEDNESDAY MORNING...ALTHOUGH THICKNESS
VALUES WILL INCREASE...DEWPOINTS TUESDAY AFTERNOON ARE EXPECTED TO
DROP INTO THE 30S ACROSS THE REGION. HIGH PRESSURE IS ALSO
EXPECTED TO MOVE DIRECTLY OVERHEAD. SO WITH LIGHT WINDS AND
EXCELLENT RADIATIONAL COOLING...TEMPERATURES WILL GET NEAR THE
SAME OR EVEN COLDER THAN TUESDAY MORNING.
SURFACE HIGH PRESSURE WILL REMAIN IN CONTROL OF THE WEATHER
THROUGH THE END OF THE WEEK. TEMPERATURES ARE EXPECTED TO SLOWLY
REBOUND TO NEAR NORMAL.
AVIATION...
SHOWERS STILL LINGER OVER EASTERN PORTIONS OF THE
REGION AS A COLD FRONT PASSES. VCSH IS CARRIED FOR THE EAST COAST
TERMINALS THROUGH 20Z. BRIEF CEILING AND VISIBILITY REDUCTIONS
ARE POSSIBLE IN ANY SHRA. OTHERWISE, WIND SPEEDS REMAIN THE
PRIMARY CONCERN WITH GUSTS OF 25 TO 30 KNOTS POSSIBLE THROUGH AT
LEAST 00Z. PREVAILING VFR EXPECTED THIS EVENING AND OVERNIGHT.
MARINE...
HAZARDOUS MARINE CONDITIONS WILL CONTINUE OVER THE ATLANTIC AND
GULF WATERS THROUGH LATE TONIGHT AND START TO SUBSIDE.
HOWEVER...AS A STRONG UPPER LEVEL TROUGH DIGS INTO THE
SOUTHEAST...A SECONDARY PUSH OF STRONG NORTHWESTERLY WINDS ARE
EXPECTED ACROSS THE LOCAL WATERS LATE MONDAY MORNING THROUGH
MONDAY NIGHT.
FIRE WEATHER...
A VERY DRY AIRMASS SHOULD SPREAD SOUTH WITH RH VALUES FALLING
BELOW 35% FOR SEVERAL HOURS ACROSS A GOOD PORTION OF SOUTH
FLORIDA BY MONDAY AFTERNOON AND ACROSS ALL OF THE AREA ON TUESDAY
AND WEDNESDAY. WINDS WILL INCREASE ON MONDAY AS A SECONDARY SURGE
OF DRIER AIR MOVES ACROSS THE REGION...WITH WINDS ACROSS THE WEST
COAST EXPECTED TO BE ABOVE 15 MPH. HOWEVER...WITH THE RECENT
RAINFALL...ERC VALUES ARE EXPECTED TO REMAIN BELOW 20. SO A FIRE
WEATHER WATCH IS NOT GOING TO BE ISSUED AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 57 74 52 / 0 0 0 0
FORT LAUDERDALE 83 59 76 58 / 0 0 0 0
MIAMI 82 59 76 59 / 0 0 0 0
NAPLES 81 57 73 53 / 0 0 0 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK UNTIL 11 AM EDT THIS MORNING FOR COASTAL
COLLIER.
AM...SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
BISCAYNE BAY-LAKE OKEECHOBEE.
GM...SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...47/RGH
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
710 PM EDT TUE APR 24 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 340 PM EDT TUE APR 24 2012
A WARM FRONT TAKING SHAPE OVER THE PLAINS AND AN UPPER WAVE MOVING
IN FROM THE NORTHERN PLAINS SHOULD BRING CHANCES FOR THUNDERSTORMS
TO THE AREA WEDNESDAY AFTERNOON AND INTO THURSDAY. BY THURSDAY NIGHT
ANOTHER FRONTAL SYSTEM WILL BRING MORE CHANCES TO THE AREA FOR MUCH
OF THE WEEKEND BY STALLING THE FRONT AND HAVING SEVERAL WAVES MOVE
ALONG IT. BY SUNDAY NIGHT UPPER RIDGING FINALLY STARTS MOVING IN TO
DRY THINGS OUT UNTIL TUESDAY.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 340 PM EDT TUE APR 24 2012
RADAR ECHOES ACROSS WESTERN INDIANA AT 19Z ARE NOT PRODUCING
ANYTHING BUT VIRGA AT THIS POINT. THOSE OVER ILLINOIS ARE
OCCASIONALLY BEING OBSERVED BY ASOS BUT STILL HAVE NOT SEEN ANYTHING
MEASURABLE THERE EITHER. WITH THIS IN MIND AND NO FORCING ARRIVING
TO INTENSIFY THE LIFT OR ADVECT IN MUCH BETTER MOISTURE HAVE DECIDED
TO GO DRIER THAN GUIDANCE AND HRRR AND MAINTAIN JUST A SLIGHT CHANCE
IN THE SOUTHWESTERN COUNTIES WHERE DEW POINTS AT LEAST ARE IN THE
30S AND LOW 40S. WITH THE DRY AIR IT WILL JUST BE VERY DIFFICULT FOR
ANY SORT OF MEASURABLE PRECIPITATION TO TAKE PLACE. WENT DRY AFTER
6Z. FOR TEMPERATURES STUCK CLOSE TO WARMER MAV NUMBERS AS THESE HAVE
BEEN VERIFYING BETTER LATELY AND THAT PRODUCED LOWS IN THE 40S.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 340 PM EDT TUE APR 24 2012
FORECAST FOCUS IS ON POPS/THUNDER POTENTIAL. MODELS ARE IN GOOD
AGREEMENT AND WILL USE A CONSENSUS APPROACH FOR THE MOST PART.
WEDNESDAY SHOULD START OUT DRY WITH INCREASING CLOUDS AS A WARM
FRONT FIRMS UP A BIT MORE SOUTH OF THE AREA AND AN UPPER WAVE
APPROACHES FROM THE NORTHWEST. BY AFTERNOON THESE AFOREMENTIONED
FEATURES SHOULD BRING CHANCES FOR THUNDERSTORMS TO THE AREA.
OVERNIGHT THE SURFACE LOW WILL DRAG A COLD FRONT THROUGH THE AREA
AND AN UPPER WAVE WILL MOVE THROUGH AS WELL...AND THIS SHOULD BRING
THE BEST CHANCES FOR PRECIPITATION IN THE SHORT TERM. THUS WENT
ALONG WITH LIKELIES IN THE MAV. DID CUT THE NORTH FROM THEIR LOW END
CATEGORICAL OF THE MAV AS COVERAGE MAY NOT BE QUITE THAT GREAT BUT
THOUGHT HIGH END LIKELIES CAPTURED THE THREAT WELL. ENTIRE FORECAST
AREA IS IN A DAY 2 SLIGHT RISK BASED ON STEEP MID LEVEL LAPSE RATES
BEING ABLE TO AID IN HAIL PRODUCTION...BUT WITH MODELS OVERDOING
MOISTURE RETURN AND THUS INSTABILITY THINK WIDESPREAD SEVERE
POTENTIAL IS LOW AND MORE INCLINED TO BELIEVE MOST STORMS WILL
PRODUCE LOW END HAIL AND ONLY ISOLATED STORMS WILL PRODUCE EVEN
QUARTER SIZE HAIL.
FOR THURSDAY THERE IS SOME DISAGREEMENT ON HOW FAR SOUTH THE FRONT
WILL GET. THUS THURSDAY MORNING MAINTAINED A CHANCE ACROSS SOUTHERN
HALF OR SO OF THE AREA TAPERING TO DRY IN THE NORTH. BY AFTERNOON
THE FRONT SHOULD BE FAR ENOUGH AWAY THAT DROPPED TO JUST A SLIGHT
CHANCE ON THE SOUTHERN BORDER. MODELS ARE FASTER WITH PROGRESSING
ANOTHER FRONT FROM THE PLAINS HOWEVER AND BRINGING SOME ISENTROPIC
LIFT OVERNIGHT THURSDAY SO EXPANDED POPS A BIT MORE TO ALL BUT THE
NORTHEASTERN COUNTIES. ON FRIDAY THIS FRONT SHOULD BE MOVING NORTH
INTO THE AREA AND WENT WITH CHANCE ACROSS THE ENTIRE AREA. DEPENDING
ON IF THIS FRONT STALLS AND STAYS FAIRLY STATIONARY INTO THE WEEKEND
AS SOME MODELS ARE PREDICTING...COULD SEE SOME DECENT RAINFALL
AMOUNTS.
FOR TEMPERATURES GENERALLY WENT CLOSER TO WARMER GUIDANCE NUMBERS AS
THIS HAS BEEN VERIFYING BETTER LATELY.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 340 PM EDT TUE APR 24 2012
THERE IS A BETTER CONSENSUS AMONG THE MODELS ON WHEN THE
PRECIPITATION WILL OCCUR DURING THE EXTENDED PERIOD. REALLY THE BEST
CHANCES WILL RUN FROM FRIDAY THROUGH SATURDAY...WITH SOME LOWER
CHANCES SATURDAY NIGHT AND ONLY A SLIGHT CHANCE BY SUNDAY. FELT
CONFIDENT ENOUGH IN LONG TERM ENSEMBLES TO BUMPED POPS UP TO LIKELY
FRIDAY NIGHT THROUGH SATURDAY...THOUGH CHANCES FOR CONVECTION LOOK
LOW/WEAK AND KEPT THUNDER MENTION AT CHANCE TO ISOLATED. THE BULK OF
THE INSTABILITY LIES FARTHER SOUTH OF THE FORECAST AREA...CLOSER TO
THE FRONTAL BOUNDARY. LOOKS DRY FOR EARLY NEXT WORK WEEK AS RIDGE
BUILDS BACK OVER THE REGION.
&&
.AVIATION /DISCUSSION FOR THE 250000Z TAF ISSUANCE/...
ISSUED AT 710 PM EDT TUE APR 24 2012
BASED ON RADAR AND OBSERVATION TRENDS...SOME OF THE VERY LIGHT RAIN
WAS MAKING IT TO THE GROUND LATE THIS AFTERNOON. STILL...DO NOT
EXPECT IT TO LAST LONG WITH THE LOW LEVELS SO DRY...SUBSIDENCE
MOVING IN ALOFT AND MODEL TIME SECTIONS INDICATING DECREASING MID
LEVEL MOISTURE OVERNIGHT. SHOULD START TO SEE SOME THUNDERSTORMS
WEDNESDAY AFTER 18Z FROM SOUTHWEST TO NORTHEAST...AS A WARM FRONT
MOVES INTO SOUTHWESTERN INDIANA AND INSTABILITY INCREASES. WITH
LIKELY POPS IN THE ZONES...HAD TO ADD VCTS AND CB GROUPS.
OTHERWISE...VFR CONDITIONS SHOULD REMAIN THROUGH THE TAF PERIOD
EXPECT PERHAPS IN THUNDERSTORMS. WINDS WILL BECOME LIGHT TONIGHT
BEFORE INCREASE TO 10 KNOTS OR MORE FROM THE SOUTH AS THE WARM FRONT
MOVES INTO SOUTHWESTERN INDIANA AFTER 12Z WEDNESDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....SMF
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
127 PM EDT MON APR 23 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 333 AM EDT MON APR 23 2012
HIGH PRESSURE OVER PLAINS AND DEEP LOW PRESSURE ALONG MID ATLANTIC
COAST MAINTAINING BRISK CONDITIONS ACROSS CENTRAL INDIANA AGAIN
TODAY. WHILE EAST COAST LOW WINDS BACK TO LAKE ONTARIO...WEAK
SHORT WAVES TOPPING WESTERN US RIDGE WILL BRING A FEW PATCHES OF
CLOUD TO WESTERN INDIANA...POSSIBLY WITH SOME LIGHT SHOWERS BY
LATE TUESDAY. FLATTENING UPPER PATTERN AND OPENING OF EAST COAST
UPPER LOW ALLOWS LOW PRESSURE TO WORK ITS WAY INTO GREAT LAKES AND
OHIO VALLEY WEDNESDAY WITH BETTER CHANCES OF SHOWERS AND SOME
STORMS. REMAINING PART OF WEEK WEATHER DEPENDENT ON HOW FAR SOUTH
FRONT WILL PUSH AND CANADIAN HIGH PRESSURE BUILDS IN.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1123 AM EDT MON APR 23 2012
MOSTLY TO COMPLETELY SUNNY SKIES ACROSS THE AREA THIS MORNING WITH
ONLY A FEW WISPY CIRRUS IN PLACES. TEMPERATURES ESPECIALLY IN
THE WESTERN COUNTIES ARE RISING A BIT FASTER THAN FORECAST AND
BASED ON 850 ADVECTION THINK THIS WILL CONTINUE INTO THE AFTERNOON
AND RESULT IN HIGHS A COUPLE DEGREES WARMER THAN EARLIER FORECAST
YIELDING UPPER 50S IN THE EAST TO LOW 60S IN THE WEST. RUC AND
HRRR ARE SHOWING WIND GUSTS A BIT STRONGER THAN GOING FORECAST AS
WELL SO BUMPED THOSE UP ESPECIALLY IN THE EAST WHERE THE GRADIENT
WILL BE TIGHTER TO 30-35 KTS DURING THE AFTERNOON. WITH THIS IN
MIND WILL ALSO ISSUE AN SPS MOMENTARILY TO HIGHLIGHT THESE GUSTY
WINDS. MOST DEW POINTS WERE ON TRACK BUT TWEAKED THOSE THAT WERE
A BIT HIGHER/LOWER TO MATCH CURRENT CONDITIONS AND WILL HAVE TO
WATCH THESE THIS AFTERNOON IF THEY MIX DOWN FURTHER AND UPDATE IF
THIS HAPPENS DUE TO THE EFFECT ON FIRE WEATHER THREAT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 333 AM EDT MON APR 23 2012
PRIMARY ISSUE IS PRECIPITATION CHANCES BEGINNING LATE TUESDAY.
ANOTHER VERY COOL NIGHT EXPECTED TONIGHT BUT WITH WINDS REMAINING
UP ENOUGH TO PREVENT ANY FROST. WILL ALSO BE FLIRTING WITH
FREEZING TEMPERATURES ACROSS NORTHERN COUNTIES TONIGHT BUT WITH
MAXS TODAY TAD WARMER THAN SUNDAY AND WITH MIXING THROUGH THE
NIGHT EXPECT MINS TO STAY 33 OR 34 DEGREES AT COLDEST.
CLOUDS INCREASE ESPECIALLY ACROSS WESTERN COUNTIES TUESDAY
AFTERNOON AS WEAK SHORT WAVE DROPS SOUTHEAST FROM CANADA. NAM AND
GFS ALSO DEVELOP ENOUGH LIFT FOR SLIGHT RAIN CHANCES SO HAVE ADDED
CHANCE OF SHOWERS TO SOUTHERN COUNTIES. MAX TEMPERATURES WITH
HIGHER THICKNESSES SHOULD TOP OUT A CATEGORY HIGHER AT LEAST TUESDAY
WITH LOWER TO MIDDLE 60S MOST AREAS.
AS SFC WARM FRONT BEGINS TO SET UP JUST SOUTH OF FORECAST
AREA...CONTINUED LOW THREAT FOR SHOWERS INTO TUESDAY NIGHT.
CLOUDIER SKIES AND WARM ADVECTION WILL ALSO KEEP MIN TEMPS IN LOWER
TO MIDDLE 40S.
COMBINATION OF SURFACE TROUGH IN AREA AND SOMEWHAT STRONGER SHORT
WAVE DROPPING SOUTHEAST IN NORTHWEST UPPER FLOW...SCATTERED
SHOWERS AND THUNDERSTORMS APPEAR PRETTY GOOD BET FOR WEDNESDAY AND
WEDNESDAY NIGHT. MILDER MAX TEMPS IN 70S AND MINS IN 50S SHOULD
ACCOMPANY THIS SYSTEM BEFORE COOL HIGH BEGINS TO BUILD IN AGAIN BY
THURSDAY. OUTSIDE POTENTIAL FOR SOME LOCALLY HEAVY RAIN WEDNESDAY
NIGHT BUT TOO EARLY TO DETERMINE WHERE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/
DISAGREEMENT BETWEEN GFS AND EURO IS MAKING POPS CHALLENGING FOR
MOST OF THE EXTENDED PERIOD. AT THIS TIME...THE EURO IS PULLING
POPS OUT OF THE AREA ON THURSDAY MORNING FASTER THAN THE GFS.
SO...IT/S REALLY A MATTER OF WHICH MODEL YOU CHOOSE...AND AM NOT
PARTIAL TO ONE OR THE OTHER AT THIS TIME. SO...WILL STAY WITH LATEST
INITIALIZATION OF SLIGHT CHANCE POPS ACROSS THE SOUTHERN HALF OF
FORECAST AREA THROUGH THURSDAY MORNING.
DRY CONDITIONS WILL PREVAIL ON THURSDAY AND THURSDAY NIGHT...BUT IT
WILL BE SHORT-LIVED AS THE NEXT LOW EJECTS OUT OF THE CENTRAL PLAINS
AT THE END OF THE WEEK. ONCE AGAIN...SIGNIFICANT MODEL UNCERTAINTY
WITH THE GFS BEING MORE PROGRESSIVE THAN EURO. INITIALIZATION SEEMS
TO BE BEST BET AT THIS TIME WITH SLIGHT CHANCE POPS ON FRIDAY
MORNING AND AFTERNOON...AND THEN INCREASING TO CHANCE POPS ON FRIDAY
EVENING. TOO MUCH VARIATION IN TIMING AND INTENSITY OF PRECIP TO GO
ANY HIGHER THAN CHANCE POPS THROUGH THE WEEKEND...BUT MODELS DO
AGREE ON KEEPING PRECIP AROUND THROUGH SUNDAY NIGHT.
TEMPS...DEVIATED FROM INITIALIZATION NUMBERS ON SATURDAY/S HIGHS.
TRENDED ON THE WARM SIDE DUE TO IMPENDING WARM FRONT WITH
AFOREMENTIONED LOW PRESSURE SYSTEM.
&&
.AVIATION /DISCUSSION FOR THE 231800Z TAF ISSUANCE/...
ISSUED AT 118 PM EDT MON APR 23 2012
VFR CONDITIONS WILL PREVAIL FOR ENTIRE TAF PERIOD (THOUGH IT
CONTINUE TO BE QUITE GUSTY THROUGH THIS AFTERNOON) WITH A LARGE
RIDGE OF HIGH PRESSURE ANCHORED OVER THE CENTRAL U.S.
A TIGHT PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED RIDGE AND
DEEP TROUGH OVER THE NORTHEAST U.S. WILL ALLOW GUSTY
NORTH/NORTHWESTERLY WINDS THROUGH EARLY THIS EVENING. SUSTAINED
SPEEDS WILL RANGE BETWEEN 18 TO 20 KTS WITH GUSTS TO 30-33 KTS AT
KLAF AND KIND. WINDS WILL BE A TAD LIGHTER AT KHUF AND KBMG WHERE
THE GRADIENT IS NOT QUITE AT STRONG. WINDS WILL DECREASE AND GUSTS
WILL DROP OFF TONIGHT...BUT STILL STAY AOA 5-7 KT OVERNIGHT. WINDS
PICK BACK UP TO AROUND 10 KT TUE MORNING AROUND 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...CP
SHORT TERM...TUCEK
LONG TERM....TDUD
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1206 PM EDT MON APR 23 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 333 AM EDT MON APR 23 2012
HIGH PRESSURE OVER PLAINS AND DEEP LOW PRESSURE ALONG MID ATLANTIC
COAST MAINTAINING BRISK CONDITIONS ACROSS CENTRAL INDIANA AGAIN
TODAY. WHILE EAST COAST LOW WINDS BACK TO LAKE ONTARIO...WEAK
SHORT WAVES TOPPING WESTERN US RIDGE WILL BRING A FEW PATCHES OF
CLOUD TO WESTERN INDIANA...POSSIBLY WITH SOME LIGHT SHOWERS BY
LATE TUESDAY. FLATTENING UPPER PATTERN AND OPENING OF EAST COAST
UPPER LOW ALLOWS LOW PRESSURE TO WORK ITS WAY INTO GREAT LAKES AND
OHIO VALLEY WEDNESDAY WITH BETTER CHANCES OF SHOWERS AND SOME
STORMS. REMAINING PART OF WEEK WEATHER DEPENDENT ON HOW FAR SOUTH
FRONT WILL PUSH AND CANADIAN HIGH PRESSURE BUILDS IN.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1123 AM EDT MON APR 23 2012
MOSTLY TO COMPLETELY SUNNY SKIES ACROSS THE AREA THIS MORNING WITH
ONLY A FEW WISPY CIRRUS IN PLACES. TEMPERATURES ESPECIALLY IN
THE WESTERN COUNTIES ARE RISING A BIT FASTER THAN FORECAST AND
BASED ON 850 ADVECTION THINK THIS WILL CONTINUE INTO THE AFTERNOON
AND RESULT IN HIGHS A COUPLE DEGREES WARMER THAN EARLIER FORECAST
YIELDING UPPER 50S IN THE EAST TO LOW 60S IN THE WEST. RUC AND
HRRR ARE SHOWING WIND GUSTS A BIT STRONGER THAN GOING FORECAST AS
WELL SO BUMPED THOSE UP ESPECIALLY IN THE EAST WHERE THE GRADIENT
WILL BE TIGHTER TO 30-35 KTS DURING THE AFTERNOON. WITH THIS IN
MIND WILL ALSO ISSUE AN SPS MOMENTARILY TO HIGHLIGHT THESE GUSTY
WINDS. MOST DEW POINTS WERE ON TRACK BUT TWEAKED THOSE THAT WERE
A BIT HIGHER/LOWER TO MATCH CURRENT CONDITIONS AND WILL HAVE TO
WATCH THESE THIS AFTERNOON IF THEY MIX DOWN FURTHER AND UPDATE IF
THIS HAPPENS DUE TO THE EFFECT ON FIRE WEATHER THREAT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 333 AM EDT MON APR 23 2012
PRIMARY ISSUE IS PRECIPITATION CHANCES BEGINNING LATE TUESDAY.
ANOTHER VERY COOL NIGHT EXPECTED TONIGHT BUT WITH WINDS REMAINING
UP ENOUGH TO PREVENT ANY FROST. WILL ALSO BE FLIRTING WITH
FREEZING TEMPERATURES ACROSS NORTHERN COUNTIES TONIGHT BUT WITH
MAXS TODAY TAD WARMER THAN SUNDAY AND WITH MIXING THROUGH THE
NIGHT EXPECT MINS TO STAY 33 OR 34 DEGREES AT COLDEST.
CLOUDS INCREASE ESPECIALLY ACROSS WESTERN COUNTIES TUESDAY
AFTERNOON AS WEAK SHORT WAVE DROPS SOUTHEAST FROM CANADA. NAM AND
GFS ALSO DEVELOP ENOUGH LIFT FOR SLIGHT RAIN CHANCES SO HAVE ADDED
CHANCE OF SHOWERS TO SOUTHERN COUNTIES. MAX TEMPERATURES WITH
HIGHER THICKNESSES SHOULD TOP OUT A CATEGORY HIGHER AT LEAST TUESDAY
WITH LOWER TO MIDDLE 60S MOST AREAS.
AS SFC WARM FRONT BEGINS TO SET UP JUST SOUTH OF FORECAST
AREA...CONTINUED LOW THREAT FOR SHOWERS INTO TUESDAY NIGHT.
CLOUDIER SKIES AND WARM ADVECTION WILL ALSO KEEP MIN TEMPS IN LOWER
TO MIDDLE 40S.
COMBINATION OF SURFACE TROUGH IN AREA AND SOMEWHAT STRONGER SHORT
WAVE DROPPING SOUTHEAST IN NORTHWEST UPPER FLOW...SCATTERED
SHOWERS AND THUNDERSTORMS APPEAR PRETTY GOOD BET FOR WEDNESDAY AND
WEDNESDAY NIGHT. MILDER MAX TEMPS IN 70S AND MINS IN 50S SHOULD
ACCOMPANY THIS SYSTEM BEFORE COOL HIGH BEGINS TO BUILD IN AGAIN BY
THURSDAY. OUTSIDE POTENTIAL FOR SOME LOCALLY HEAVY RAIN WEDNESDAY
NIGHT BUT TOO EARLY TO DETERMINE WHERE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/
DISAGREEMENT BETWEEN GFS AND EURO IS MAKING POPS CHALLENGING FOR
MOST OF THE EXTENDED PERIOD. AT THIS TIME...THE EURO IS PULLING
POPS OUT OF THE AREA ON THURSDAY MORNING FASTER THAN THE GFS.
SO...IT/S REALLY A MATTER OF WHICH MODEL YOU CHOOSE...AND AM NOT
PARTIAL TO ONE OR THE OTHER AT THIS TIME. SO...WILL STAY WITH LATEST
INITIALIZATION OF SLIGHT CHANCE POPS ACROSS THE SOUTHERN HALF OF
FORECAST AREA THROUGH THURSDAY MORNING.
DRY CONDITIONS WILL PREVAIL ON THURSDAY AND THURSDAY NIGHT...BUT IT
WILL BE SHORT-LIVED AS THE NEXT LOW EJECTS OUT OF THE CENTRAL PLAINS
AT THE END OF THE WEEK. ONCE AGAIN...SIGNIFICANT MODEL UNCERTAINTY
WITH THE GFS BEING MORE PROGRESSIVE THAN EURO. INITIALIZATION SEEMS
TO BE BEST BET AT THIS TIME WITH SLIGHT CHANCE POPS ON FRIDAY
MORNING AND AFTERNOON...AND THEN INCREASING TO CHANCE POPS ON FRIDAY
EVENING. TOO MUCH VARIATION IN TIMING AND INTENSITY OF PRECIP TO GO
ANY HIGHER THAN CHANCE POPS THROUGH THE WEEKEND...BUT MODELS DO
AGREE ON KEEPING PRECIP AROUND THROUGH SUNDAY NIGHT.
TEMPS...DEVIATED FROM INITIALIZATION NUMBERS ON SATURDAY/S HIGHS.
TRENDED ON THE WARM SIDE DUE TO IMPENDING WARM FRONT WITH
AFOREMENTIONED LOW PRESSURE SYSTEM.
&&
.AVIATION /DISCUSSION FOR THE 231200Z TAF ISSUANCE/...
ISSUED AT 1203 PM EDT MON APR 23 2012
1600Z UPDATE...WINDS ARE PICKING UP AND GUSTING VERY STRONG AN
HOUR OR TWO THAN EARLIER EXPECTED...AND ARE ACTUALLY A LITTLE
STRONGER AT LOCATIONS SUCH AS KIND. ALL TAFS HAVE BEEN UPDATED TO
REFLECT THIS STRONGER GUSTY TREND FOR THE REST OF THIS ATFTERNOON.
PREVIOUS DISCUSSIONS FOLLOW...
ISSUED AT 1052 AM EDT MON APR 23 2012
1030Z UPDATE...NO UPDATES NEEDED AT THIS TIME. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 653 AM EDT MON APR 23 2012
VFR CONDITIONS WILL PREVAIL FOR ENTIRE TAF PERIOD WITH LARGE RIDGE
OF HIGH PRESSURE ANCHORED OVER THE CENTRAL U.S.
HOWEVER...A TIGHT PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED
RIDGE AND DEEP TROUGH OVER THE NORTHEAST U.S. WILL RESULT IN GUSTY
NORTH/NORTHWESTERLY WINDS THROUGH THIS EVENING. WINDS WILL START
INCREASING AROUND MID TO LATE MORNING AND CONTINUE TO STRENGTHEN
THROUGH MIDDAY. SUSTAINED SPEEDS WILL RANGE BETWEEN 18 TO 20 KTS
WITH GUSTS TO 30 KTS AT KLAF AND KIND. WINDS WILL BE A TAD LIGHTER
AT KHUF AND KBMG WHERE THE GRADIENT WON/T BE AS TIGHT. SUSTAINED
SPEEDS AT THOSE SITES WILL RANGE FROM 10 TO 14 KTS WITH GUSTS TO
25 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...CP
SHORT TERM...TUCEK
LONG TERM....TDUD
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1124 AM EDT MON APR 23 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 333 AM EDT MON APR 23 2012
HIGH PRESSURE OVER PLAINS AND DEEP LOW PRESSURE ALONG MID ATLANTIC
COAST MAINTAINING BRISK CONDITIONS ACROSS CENTRAL INDIANA AGAIN
TODAY. WHILE EAST COAST LOW WINDS BACK TO LAKE ONTARIO...WEAK
SHORT WAVES TOPPING WESTERN US RIDGE WILL BRING A FEW PATCHES OF
CLOUD TO WESTERN INDIANA...POSSIBLY WITH SOME LIGHT SHOWERS BY
LATE TUESDAY. FLATTENING UPPER PATTERN AND OPENING OF EAST COAST
UPPER LOW ALLOWS LOW PRESSURE TO WORK ITS WAY INTO GREAT LAKES AND
OHIO VALLEY WEDNESDAY WITH BETTER CHANCES OF SHOWERS AND SOME
STORMS. REMAINING PART OF WEEK WEATHER DEPENDENT ON HOW FAR SOUTH
FRONT WILL PUSH AND CANADIAN HIGH PRESSURE BUILDS IN.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1123 AM EDT MON APR 23 2012
MOSTLY TO COMPLETELY SUNNY SKIES ACROSS THE AREA THIS MORNING WITH
ONLY A FEW WISPY CIRRUS IN PLACES. TEMPERATURES ESPECIALLY IN
THE WESTERN COUNTIES ARE RISING A BIT FASTER THAN FORECAST AND
BASED ON 850 ADVECTION THINK THIS WILL CONTINUE INTO THE AFTERNOON
AND RESULT IN HIGHS A COUPLE DEGREES WARMER THAN EARLIER FORECAST
YIELDING UPPER 50S IN THE EAST TO LOW 60S IN THE WEST. RUC AND
HRRR ARE SHOWING WIND GUSTS A BIT STRONGER THAN GOING FORECAST AS
WELL SO BUMPED THOSE UP ESPECIALLY IN THE EAST WHERE THE GRADIENT
WILL BE TIGHTER TO 30-35 KTS DURING THE AFTERNOON. WITH THIS IN
MIND WILL ALSO ISSUE AN SPS MOMENTARILY TO HIGHLIGHT THESE GUSTY
WINDS. MOST DEW POINTS WERE ON TRACK BUT TWEAKED THOSE THAT WERE
A BIT HIGHER/LOWER TO MATCH CURRENT CONDITIONS AND WILL HAVE TO
WATCH THESE THIS AFTERNOON IF THEY MIX DOWN FURTHER AND UPDATE IF
THIS HAPPENS DUE TO THE EFFECT ON FIRE WEATHER THREAT.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
ISSUED AT 333 AM EDT MON APR 23 2012
PRIMARY ISSUE IS PRECIPITATION CHANCES BEGINNING LATE TUESDAY.
ANOTHER VERY COOL NIGHT EXPECTED TONIGHT BUT WITH WINDS REMAINING
UP ENOUGH TO PREVENT ANY FROST. WILL ALSO BE FLIRTING WITH
FREEZING TEMPERATURES ACROSS NORTHERN COUNTIES TONIGHT BUT WITH
MAXS TODAY TAD WARMER THAN SUNDAY AND WITH MIXING THROUGH THE
NIGHT EXPECT MINS TO STAY 33 OR 34 DEGREES AT COLDEST.
CLOUDS INCREASE ESPECIALLY ACROSS WESTERN COUNTIES TUESDAY
AFTERNOON AS WEAK SHORT WAVE DROPS SOUTHEAST FROM CANADA. NAM AND
GFS ALSO DEVELOP ENOUGH LIFT FOR SLIGHT RAIN CHANCES SO HAVE ADDED
CHANCE OF SHOWERS TO SOUTHERN COUNTIES. MAX TEMPERATURES WITH
HIGHER THICKNESSES SHOULD TOP OUT A CATEGORY HIGHER AT LEAST TUESDAY
WITH LOWER TO MIDDLE 60S MOST AREAS.
AS SFC WARM FRONT BEGINS TO SET UP JUST SOUTH OF FORECAST
AREA...CONTINUED LOW THREAT FOR SHOWERS INTO TUESDAY NIGHT.
CLOUDIER SKIES AND WARM ADVECTION WILL ALSO KEEP MIN TEMPS IN LOWER
TO MIDDLE 40S.
COMBINATION OF SURFACE TROUGH IN AREA AND SOMEWHAT STRONGER SHORT
WAVE DROPPING SOUTHEAST IN NORTHWEST UPPER FLOW...SCATTERED
SHOWERS AND THUNDERSTORMS APPEAR PRETTY GOOD BET FOR WEDNESDAY AND
WEDNESDAY NIGHT. MILDER MAX TEMPS IN 70S AND MINS IN 50S SHOULD
ACCOMPANY THIS SYSTEM BEFORE COOL HIGH BEGINS TO BUILD IN AGAIN BY
THURSDAY. OUTSIDE POTENTIAL FOR SOME LOCALLY HEAVY RAIN WEDNESDAY
NIGHT BUT TOO EARLY TO DETERMINE WHERE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/
DISAGREEMENT BETWEEN GFS AND EURO IS MAKING POPS CHALLENGING FOR
MOST OF THE EXTENDED PERIOD. AT THIS TIME...THE EURO IS PULLING
POPS OUT OF THE AREA ON THURSDAY MORNING FASTER THAN THE GFS.
SO...IT/S REALLY A MATTER OF WHICH MODEL YOU CHOOSE...AND AM NOT
PARTIAL TO ONE OR THE OTHER AT THIS TIME. SO...WILL STAY WITH LATEST
INITIALIZATION OF SLIGHT CHANCE POPS ACROSS THE SOUTHERN HALF OF
FORECAST AREA THROUGH THURSDAY MORNING.
DRY CONDITIONS WILL PREVAIL ON THURSDAY AND THURSDAY NIGHT...BUT IT
WILL BE SHORT-LIVED AS THE NEXT LOW EJECTS OUT OF THE CENTRAL PLAINS
AT THE END OF THE WEEK. ONCE AGAIN...SIGNIFICANT MODEL UNCERTAINTY
WITH THE GFS BEING MORE PROGRESSIVE THAN EURO. INITIALIZATION SEEMS
TO BE BEST BET AT THIS TIME WITH SLIGHT CHANCE POPS ON FRIDAY
MORNING AND AFTERNOON...AND THEN INCREASING TO CHANCE POPS ON FRIDAY
EVENING. TOO MUCH VARIATION IN TIMING AND INTENSITY OF PRECIP TO GO
ANY HIGHER THAN CHANCE POPS THROUGH THE WEEKEND...BUT MODELS DO
AGREE ON KEEPING PRECIP AROUND THROUGH SUNDAY NIGHT.
TEMPS...DEVIATED FROM INITIALIZATION NUMBERS ON SATURDAY/S HIGHS.
TRENDED ON THE WARM SIDE DUE TO IMPENDING WARM FRONT WITH
AFOREMENTIONED LOW PRESSURE SYSTEM.
&&
.AVIATION /DISCUSSION FOR THE 231200Z TAF ISSUANCE/...
ISSUED AT 1052 AM EDT MON APR 23 2012
1030Z UPDATE...NO UPDATES NEEDED AT THIS TIME. PREVIOUS DISCUSSION
FOLLOWS...
ISSUED AT 653 AM EDT MON APR 23 2012
VFR CONDITIONS WILL PREVAIL FOR ENTIRE TAF PERIOD WITH LARGE RIDGE
OF HIGH PRESSURE ANCHORED OVER THE CENTRAL U.S.
HOWEVER...A TIGHT PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED
RIDGE AND DEEP TROUGH OVER THE NORTHEAST U.S. WILL RESULT IN GUSTY
NORTH/NORTHWESTERLY WINDS THROUGH THIS EVENING. WINDS WILL START
INCREASING AROUND MID TO LATE MORNING AND CONTINUE TO STRENGTHEN
THROUGH MIDDAY. SUSTAINED SPEEDS WILL RANGE BETWEEN 18 TO 20 KTS
WITH GUSTS TO 30 KTS AT KLAF AND KIND. WINDS WILL BE A TAD LIGHTER
AT KHUF AND KBMG WHERE THE GRADIENT WON/T BE AS TIGHT. SUSTAINED
SPEEDS AT THOSE SITES WILL RANGE FROM 10 TO 14 KTS WITH GUSTS TO
25 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TUCEK
NEAR TERM...CP
SHORT TERM...TUCEK
LONG TERM....TDUD
AVIATION...SMF
AREA FORECAST DISCUSSION
NWS PADUCAH KY
837 PM CDT TUE APR 24 2012
.UPDATE...
ISSUED AT 837 PM CDT TUE APR 24 2012
THE HRRR HAS A GOOD HANDLE ON THE CURRENT RADAR TRENDS. WOULD
EXPECT THE AREA TO BE CLEAR OF ALL SHOWERS BY 03Z...AND SKIES WILL
BE MOSTLY CLEAR SHORTLY AFTER 06Z.
WILL BE UPDATING THE TAFS TO REMOVE THE VCTS IN A FEW MINUTES AS
WELL. HAVE UPDATED THE AVIATION SECTION TO REMOVE MENTION OF
EVENING THUNDER.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 258 PM CDT TUE APR 24 2012
THE CLOUD COVER THAT DEVELOPED MAINLY EAST OF THE MISSISSIPPI RIVER
LATE THIS MORNING AND DURING THE AFTERNOON HOURS APPEARS TO MATCH
WELL WITH THE 12Z TUESDAY 12KM NAM-WRF DYNAMIC/THERMAL FIELDS.
SHARPER MID-LEVEL LAPSE RATES...COMBINED WITH WEAK TO MODERATE
EQUIVALENT POTENTIAL VORTICITY AND 700-500 MB MID LEVEL CONVERGENCE
IS SUPPORTING THE FORMATION LEADING EDGE OF THE UPPER LEVEL WARM
FRONT.. THE ENHANCED FORCING HAS ALSO LEAD TO MORE STABLE SHOWER
ACTIVITY OVER SOUTHWEST INDIANA...WEST KENTUCKY AND SOUTHERN
ILLINOIS THIS AFTERNOON. LOWER LEVEL LAPSE RATES /BELOW 700 MB/ WILL
SHARPEN LATE THIS AFTERNOON TONIGHT AND THIS EVENING...WITH THE AID
OF SWLY LOW LEVEL JET. AT THE SAME TIME...THE 12KM NAM-WRF EDGES A
WNW-ESE NOSE OF HIGHER 0-3KM CAPE INTO SOUTHERN ILLINOIS...WEST
KENTUCKY AND SOUTHWEST INDIANA. THE COMBINATION OF THE HIGHER CAPE
AND SHARPER LAPSE RATES WILL LEAD TO MORE UPRIGHT
CONVECTION...LEADING TO SOME LIMITED THUNDERSTORM ACTIVITY MOVING IN
FROM EASTERN MO...SOUTHEAST THROUGH THE AREA THIS EVENING. THE MOST
LIKELY TRIGGER FOR THIS DESTABILIZATION THROUGH THE ATMOSPHERIC
LAYER IS A SHORTWAVE CURRENTLY MOVING OVER EASTERN NEBRASKA AND
NORTHER KANSAS...AS OF 1 PM CDT TUESDAY.
FOR THE LOCAL WFO PAH FORECAST AREA...THIS WILL LIKELY MEAN THAT THE
SCATTERED SHOWERS WILL CONTINUE...MAINLY EAST OF THE MISSISSIPPI
RIVER THROUGH THE EVENING. ISOLATED TO WIDELY SCATTERED
THUNDERSTORMS SHOULD INCREASE DURING THE LATE AFTERNOON AND EARLY
EVENING...MAINLY OVER SOUTHEAST ILLINOIS AND WEST KENTUCKY.
THE CURRENTLY DEVELOPING UPPER LEVEL WARM FRONT OVER THE NORTHEAST
HALF OF THE WFO PAH FORECAST AREA WILL SERVE AS THE EASTERN LIMIT OF
THE INCREASING 0-3KM CAPE...WITH THE MAXIMUM ZONE OF LOW LEVEL CAPE
INITIALLY FOCUSED JUST WEST OF THE UPPER LEVEL FRONT /OVER SERN
IL...SWRN IN...WRN KY/...WORKING WEST AND SOUTHWEST...AS INSTABILITY
BECOMES MORE SURFACE BASED WITH TIME ON WEDNESDAY AFTERNOON INTO
THURSDAY. THE NAM-WRF /THE PREFERRED SHORT RANGE GUIDANCE AT THIS
TIME/ SUGGESTS THAT MOST OF THE EXPENDED CAPE AND INSTABILITY WILL
BE ACROSS SOUTHEAST ILLINOIS...SOUTHWEST INDIANA AND WEST KENTUCKY
ON WEDNESDAY AND THURSDAY. THEREFORE...KEPT THE BEST CHANCES FOR
SHOWERS AND THUNDERSTORMS IN THIS AREA WEDNESDAY AND THURSDAY.
NOW THAT THE FLOW IS BECOMING MORE WEST SOUTHWEST AT LOWER
LEVELS...DEW POINTS SHOULD MARKEDLY INCREASE THIS EVENING AND
OVERNIGHT. OVERNIGHT LOWS SHOULD BE AT LEAST 3 TO 10 DEGREES
WARMER THAN TUESDAY MORNING...WITH HIGHS ON WEDNESDAY AND THURSDAY
IN THE UPPER 70S AND LOWER 80S. ALTHOUGH AN ATTEMPT WAS MADE TO
LOWER TEMPERATURES 3-4 DEGREES IN THE AREA WITH HIGHER
POP/WEATHER/OPAQUE CLOUD COVER...MAX TEMPERATURES MAY BE IMPACTED
ANYWHERE IN THE WFO PAH FORECAST AREA WHERE PERSISTENT OR REPEATED
RAINFALL OCCURS ON WEDNESDAY AND/OR THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 258 PM CDT TUE APR 24 2012
IN ESSENCE...IT LOOKS LIKE WE ARE GOING TO CONTINUE TO BE VISITED BY
A NEARLY STATIONARY SURFACE BOUNDARY THAT WILL SET UP OVER THE
REGION THU THRU FRIDAY. RAIN AND THUNDERSTORM ACTIVITY ASSOCIATED
WITH THIS FRONT WILL LIKELY BE TIED TO THE TIMING OF WEAK
DISTURBANCES ZIPPING EAST SOUTHEAST IN MID LVL FLOW...WHICH WILL BE
DIFFICULT AT BEST TO TIME. HIGHER CANCERS FOR ANY SIGNIFICANT
RAIN AS OF NOW LOOK TO BE ALONG AND NORTH OF THE SFC
FRONT...WHICH WILL BE DRAPED ALONG/NR THE OHIO RIVER THROUGH
FRIDAY...ESP IF WE CAN GET ANY INSTABILITY GENERATED BY A FEW
HOURS OF SUN IN THE AFTN...OR A DECENT NOCTURNAL JET DURING THE
NIGHT TIME HOURS. COLD BE ELEVATED STORMS WITH MAINLY SOME HAIL
POTENTIAL.
THEN...LOOKS AS THOUGH A MORE DEFINED MID LVL SHORT WAVE WILL
EJECT EAST INTO THE PLAINS SAT/SAT EVENING. THIS FEATURE MAY DRAG
THE SFC WARM FRONT BACK NORTH INTO IL/IN/MO...PUTTING AT LEAST THE
SOUTH HALF OF THE FORECAST AREA IN THE WARM SECTOR FOR AWHILE...
BEFORE A COLD FRONT SWEEPS IN FROM THE WEST SAT AFTN OR NIGHT.
THIS SCENARIO MAY OFFER THE HIGHEST CHANCE OF A MORE WIDESPREAD
OUTBREAK OF SCT STRONG TO SEVERE THUNDERSTORMS. MUCH OF THIS WILL
HINGE UPON HOW MUCH INSTABILITY CAN FORM AHEAD OF THE SYSTEM. WILL
DEFINITELY NEED TO MONITOR THO.
SHOULD DRY OUT AFTER THIS LONG WAVE TROF PASSES BY TO THE NORTH
SUNDAY/MONDAY...WITH A QUICK COOL DOWN INTO THE 60S SUN/MON TIME
FRAME.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 837 PM CDT TUE APR 24 2012
THE WARM FRONT HAS SET UP BETWEEN KCGI/KPAH AND KEVV/KOWB...AND IT
WILL LIKELY STAY THERE THROUGH THE NIGHT...AND POSSIBLY MUCH OF
WEDNESDAY. SOUTH SOUTHWEST WINDS WILL PREVAIL THROUGH THE NIGHT TO
ITS WEST...WITH LIGHT AND VARIABLE...GENERALLY EAST THROUGH
SOUTH...WINDS TO THE EAST OF IT.
THE MODELS INDICATE THE POTENTIAL FOR CONVECTION OVER SOUTH
CENTRAL MISSOURI LATE TONIGHT. EXPECT THAT IT WILL STAY WEST OF
KCGI...BUT WILL HAVE TO KEEP AN EYE ON THAT.
GENERALLY LACKING MOISTURE FOR CONVECTIVE DEVELOPMENT ON
WEDNESDAY. COULD HAVE SOME GUSTY SOUTWEST WINDS AT KCGI AND
KPAH...IF MID CLOUDS DO NOT QUASH MIXING. WOULD EXPECT THE BEST
CHANCE FOR CONVECTION ON WEDNESDAY TO BE NEAR THE WARM FRONT IN
KEVV AND KOWB IN THE LATE AFTERNOON.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...SMITH
LONG TERM....MEFFERT
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1152 PM CDT SUN APR 22 2012
.UPDATE...
ISSUED AT 1152 PM CDT SUN APR 22 2012
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.
UPDATE ISSUED AT 1020 PM CDT SUN APR 22 2012
UPDATED FORECAST TO LESSEN THE MENTION OF FROST FROM /AREAS OF/ TO
/PATCHY/...AND ACROSS A SMALLER GEOGRAPHIC AREA. A NORTH BREEZE
IS EXPECTED TO KEEP TEMPERATURES A FEW DEGREES HIGHER THAN
ORIGINALLY THOUGHT OVERNIGHT...THUS LESSENING THE POTENTIAL FOR
SIGNIFICANT FROST FORMATION. PATCHY FROST IS STILL POSSIBLE
TOWARDS DAYBREAK...MAINLY IN LOCATIONS OF SOUTHERN ILLINOIS...
SOUTHEAST MISSOURI...AND FAR WESTERN KENTUCKY THAT ARE SHELTERED
FROM THE WIND.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 305 PM CDT SUN APR 22 2012
THE SHORT TERM CONCERN FOR TONIGHT WILL BE THE DEVELOPMENT OF FROST
AFTER MIDNIGHT. IT WAS A TOUGH CALL TO DETERMINE WHETHER THE
DURATION/INTENSITY OF ANY FROST DEVELOPMENT WOULD BE ENOUGH TO
WARRANT THE ISSUANCE OF A FROST ADVISORY FOR PARTS OF THE WFO PAH
FORECAST AREA. DESPITE THE CLIMATOLOGICAL ABILITY FOR WINDS TO
DECOUPLE IN THE WFO PAH FORECAST AREA...THE ENTIRE SUITE OF HIGH
RESOLUTION AND STATISTICAL NUMERICAL GUIDANCE IS LEADING CREDENCE
THAT THE WIND GRADIENT WILL REMAIN STRONG ENOUGH TO KEEP MIXING IN
PLACE FOR MOST LOCATIONS. THIS WOULD LIMIT THE DEVELOPMENT OF
FROST TO THOSE SITES THAT ARE NORMALLY WELL PROTECTED FROM WINDS.
HOWEVER...GIVE THE UNCERTAINTY ON THE CONSISTENCY OF WINDS SPEEDS
OVER THE ENTIRE PERIOD FROM MIDNIGHT THROUGH 8 AM CDT...A SPECIAL
WEATHER STATEMENT HAS BEEN ISSUED FOR THE ENTIRE FORECAST AREA. AN
ADDITIONAL MENTION WILL BE MADE IN THE HAZARDOUS WEATHER OUTLOOK
THIS AFTERNOON. THE EVENING FORECAST WILL NEED TO MONITOR WINDS
THIS EVENING...SHOULD THE GRADIENT RELAX FASTER THAN ANTICIPATED
AT THIS TIME.
THE CURRENT CONVECTION OVER THE WFO PAH FORECAST AREA SHOULD
LESSEN WITH THE LOSS OF INSOLATION AND TRANSLATION OF THE PRIMARY
CHANNELED VORTICITY OUT OF THE AREA TONIGHT. THE POTENTIAL FOR ANY
FURTHER ENHANCED CONVECTION /THUNDERSTORMS/ OVER SOUTHEAST MO/WEST
KENTUCKY SHOULD DROP OFF MARKEDLY BEFORE 5 PM CDT...WITH ANY
SHOWER ACTIVITY DIMINISHING BEFORE 8 PM CDT. THE 3KM HRRR AND 12KM
NAM-WRF DID A FAIRLY GOOD JOB OF DEPICTING THE
LOCATION/COVERAGE/INTENSITY OF THE CONVECTION TODAY AND WAS USED
AS A TEMPLATE IN PREPARING THE GRIDDED FORECAST UPDATES.
THERE WILL STILL BE SOME MINOR COLD AIR ADVECTION AND LIFT IN THE
DEPARTING CYCLONIC FLOW ON MONDAY...SO COLLABORATED WITH WFO ST.
LOUIS IN BEING MORE AGGRESSIVE WITH DIURNALLY-BASED COLD AIR
STRATOCUMULUS DEVELOPMENT DURING THE LATE MORNING AND AFTERNOON HOURS.
.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 305 PM CDT SUN APR 22 2012
NOT MUCH CHANGE TO THE EXTENDED. PREFER TO STAY THE COURSE WITH ONLY
MINOR MODIFICATIONS VS. WHAT SOME OF THE NEW GUIDANCE...IN PARTICULAR
THE GFS IS DEPICTING. IT HAS SLOWED THE FRONTAL PASSAGE CONSIDERABLY
WEDNESDAY NIGHT THROUGH THURSDAY. IT HANGS THE FRONT UP ACROSS THE
AREA AND SUGGESTS THE CHANCE OF CONVECTION WILL NOT CLEAR THE AREA.
THIS IS IN STARK CONTRAST TO WHAT IT WAS SHOWING PRIOR. THE OTHER
MODELS CONTINUE TO PUSH THE FRONT ON THROUGH...ALTHOUGH PERHAPS NOT
QUITE AS FAR TO THE SOUTH AS PREVIOUSLY ADVERTISED. THE NEW 12Z
ECMWF CONTINUES TO PUSH THE FRONT ON THROUGH WITH TIME. BEST CHANCE
POPS WILL CONTINUE TO BE WEDNESDAY NIGHT IN CLOSE PROXIMITY TO THE
FRONT. SHRA/TSRA HIGH CHANCE TO LOW END LIKELY POPS WILL BE USED.
THE CHANCE OF ISOLATED SEVERE IS STILL UP FOR DEBATE AT THIS POINT AS
THE PARAMETERS ARE MARGINAL. HARD TO RULE OUT LOW END CHANCE POPS
FROM LATE FRIDAY ON INTO THE WEEKEND GIVEN THE UNSETTLED LOOK TO THE
PATTERN...ONCE THE MID LEVEL RIDGE PASSES BY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1152 PM CDT SUN APR 22 2012
SKIES CLEARING OUT NICELY LATE THIS EVENING. COULD STILL SEE A FEW
CLOUDS AROUND 7KFT OR SOME CIRRUS IN THE EAST OVERNIGHT...BUT
OTHERWISE IT WILL BE CLEAR. NORTH WINDS SHOULD SETTLE TO JUST UNDER
10KTS THROUGHOUT THE AREA OVERNIGHT.
DEEP MIXING IS EXPECTED TO DEVELOP MONDAY...WITH GUSTY NORTH WINDS
EXPECTED TO DESCEND AROUND 15Z. STRONGER GUSTS TO AROUND 25KTS
WILL BE POSSIBLE FROM 18Z TIL SUNSET. CEILINGS ARE LIKELY TO
DEVELOP IN THE 5-7KFT LAYER AGAIN IN THE MID TO LATE AFTERNOON
MONDAY. THERE MAY BE ENOUGH OF AN UNSTABLE LAYER TO SUPPORT SOME
LIGHT SHOWERS IN THE EARLY EVENING AT KEVV AND KOWB...SO DECIDED
TO INSERT A VFR SHOWER AT EACH SITE.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...SMITH
LONG TERM....CTN
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
358 PM EDT MON APR 23 2012
.SYNOPSIS...
DEEP LOW PRESSURE, MOVING SLOWLY NORTHWARD THROUGH NEW YORK STATE,
CAN STILL CAUSE GUSTY WINDS AND A MIX OF RAIN AND SNOW SHOWERS
TONIGHT. THE HIGHER MOUNTAINS CAN YET GET ADDITIONAL
ACCUMULATIONS OF WET SNOW. MIDWEST HIGH PRESSURE WILL COME
SLOWLY EASTBOUND TO PROVIDE DRY CONDITIONS AND MODERATING
TEMPERATURES BY WEDNESDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
PER RECENT SURFACE AND RADAR DATA, HAVE RAISED WIND GUST VALUES TO
OVER 45 MPH ACROSS EAST CENTRAL OHIO AND THE WEST VIRGINIA
NORTHERN PANHANDLE, AND SO HAVE ISSUED A WIND ADVISORY FOR THOSE
PARTS THROUGH EARLY EVENING. FURTHER EAST, WINDS CAN GUST TO 40
MPH, AS THE STRONG LOW PRESSURE SYSTEM CONTINUES TO MOVE NORTHWARD
THROUGH NEW YORK STATE.
RECENT RADAR DATA CONTINUES TO SHOW THE ASSOCIATED FRONTOGENETICALLY-
FORCED WRAP-AROUND PRECIPITATION SHIELD AFFECTING THE HIGHER
MOUNTAINS AND NORTHWEST PENNSYLVANIA I-80 CORRIDOR. WET SNOW
ACCUMULATIONS CAN OCCUR WHERE TEMPERATURES ARE COLDER THAN 34
DEGREES. TRENDS IN RADAR DATA AND HRRR AND NAM MODEL OUTPUT SHOW
THE PRECIPITATION BAND WILL BECOME MORE NORTHWEST TO SOUTHEAST
ORIENTED THIS EVENING, AND THEN SLOWLY EXIT NORTH LATE TONIGHT AND
TUESDAY MORNING.
HAVE MAINTAINED WINTER STORM WARNING THROUGH EARLY TONIGHT, AS
EXPECT ANY NEW WET SNOW ACCUMULATIONS WILL BE RESTRICTED TO THE
HIGHER MOUNTAINS.
FORECASTED LOW TEMPERATURES TONIGHT USING BLEND OF GFS AND NAM
MOS, WHICH SHOWED LOWS NO LOWER THAN THE UPPER 20S ACROSS THE
HIGHER MOUNTAINS AND NO WARMER THAN THE THE MID 30S ELSEWHERE.
TEMPERATURES WILL MODERATE DAYTIME TUESDAY, BUT AFTERNOON HIGHS
WILL BE MORE THAN 10 DEGREES COLDER THAN NORMAL PER RECENT GFS AND
NAM MOS.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
RECENT SREF MODEL OUTPUT SHOWS A SLOW EASTBOUND HIGH PRESSURE
SYSTEM PROVIDING THE UPPER OHIO VALLEY WITH A DRY BREAK TUESDAY
NIGHT INTO WEDNESDAY EVENING. THEN A LOW PRESSURE, COMING
SOUTHEAST FROM THE CANADIAN PRAIRIES, WILL BRING SHOWERS LATE
WEDNESDAY NIGHT AND POSSIBLY THUNDERSTORMS DAYTIME THURSDAY.
FORECASTED TEMPERATURES TO BE CLOSER TO SEASONABLE VALUES BASED ON
BLEND OF RECENT GFS AND NAM MOS AND SREF MEAN VALUES.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
DRY WEATHER IS EXPECTED FRIDAY AND SATURDAY AS SURFACE HIGH PRESSURE
BUILDS SOUTHEASTWARD OVER THE GREAT LAKES. MEDIUM RANGE MODELS SHOW
A LOW PRESSURE SYSTEM TRACKING EAST FROM THE PLAINS AND ACROSS THE
OHIO VALLEY SUNDAY...BRINGING SCATTERED SHOWERS. SURFACE HIGH
PRESSURE SHOULD REBUILD BEHIND THIS SYSTEM TO PROVIDE DRY WEATHER
FOR MONDAY.
TEMPERATURES ARE FORECAST TO REMAIN BETWEEN 5 AND 10 DEGREES BELOW
NORMAL THROUGH THE EXTENDED PERIOD.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
SURFACE LOW PRESSURE WILL CONTINUE TO TRACK SLOWLY NORTH INTO
SOUTHERN ONTARIO BY LATE TUESDAY. MVFR RESTRICTIONS AND AREAS OF IFR
WILL LIKELY PERSIST IN MIX OF RAIN AND SNOW ACROSS THE WESTERN PA
AND NORTHERN WEST VIRGINIA TERMINALS THROUGH TONIGHT. CONDITIONS ARE
EXPECTED TO IMPROVE TO VFR AT ALL TERMINALS EXCEPT KFKL AND KDUJ BY
LATE TUESDAY MORNING. CONDITIONS WILL REMAIN VFR AT KZZV THROUGH THE
TAF PERIOD.
NORTHWEST SURFACE WINDS WILL GUST TO 30 TO 35KT AT TIMES THROUGH
EARLY EVENING...THEN GRADUALLY SUBSIDE TO 15 TO 25KT OVERNIGHT.
.OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
A LOW PRESSURE SYSTEM PROGGED TO CROSS THE UPPER OHIO VALLEY WILL
BRING SCATTERED SHOWERS AND THE POTENTIAL FOR RESTRICTIONS LATE
WEDNESDAY NIGHT AND THURSDAY. BUILDING HIGH PRESSURE SHOULD SUPPORT
VFR WEATHER FOR FRIDAY AND SATURDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...WINTER STORM WARNING UNTIL 2 AM EDT TUESDAY FOR MDZ001.
OH...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR OHZ039>041-
048>050-057>059-068-069.
PA...WINTER STORM WARNING UNTIL 2 AM EDT TUESDAY FOR PAZ009-016-023-
074-076.
WV...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR WVZ001>004-012.
WINTER STORM WARNING UNTIL 2 AM EDT TUESDAY FOR WVZ023-041.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
636 PM EDT MON APR 23 2012
.SYNOPSIS...
ISSUED AT 414 PM EDT MON APR 23 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A HIGH AMPLITUDE PATTERN WITH
A MID/UPPER LEVEL RIDGE OVER THE WRN CONUS AND A TROUGH OVER THE
EAST RESULTING IN CONFLUENT NRLY FLOW THROUGH THE UPPER GREAT LAKES.
AN UPSTREAM SHORTWAVE TROUGH MOVING INTO NRN MANITOBA SUPPORTED AN
EXTENSIVE AREA OF CLOUDS AND A FEW LIGHT SHOWERS. AT THE SFC...THE
GRADIENT WAS INCREASING BTWN LOW PRESSURE OVER ERN NY AND A RIDGE
OVER THE UPPER MS VALLEY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 414 PM EDT MON APR 23 2012
AS THE SHORTWAVE TROUGH MOVES TOWARD THE AREA...EXPECT MID CLOUDS TO
INCREASE LATE TONIGHT. THE GFS WAS MORE AGGRESSIVE WITH 290K
ISENTROPIC LIFT AND PCPN POTENTIAL COMPARED TO THE REST OF THE
MODELS. SO...GIVEN THE LACK OF MOISTURE AVBL AND THE RELATIVELY
MODEST DYNAMICS...ONLY SLIGHT CHANCE POPS WERE INCLUDED OVER WEST.
SOME INLAND TEMPS MAY FALL TO NEAR FREEZING BUT SOUNDINGS SUGGEST
THAT PCPN TYPE WOULD BE RAIN.
RELATIVELY POOR RH RECOVERY IS EXPECTED OVERNIGHT ACROSS THE
AREA...BUT MOST SIGNIFICANTLY OVER THE EASTERN HALF. EVEN WITH THE
LOSS OF DAYTIME HEATING/MIXING 9250 MB WINDS IN THE 40 TO 45 KT
RANGE...FROM 03Z TO 15Z TUESDAY. AFTER AREAS OF CLOUDS WITH THE
SHRTWV MOVE OUT BY AFTERNOON...SUNSHINE AND MIXING SHOULD AGAIN DROP
DEWPOINTS BLO GUIDANCE TO AROUND 20F. WITH TEMPERATURES INTO THE MID
AND UPPER 50S...RH VALUES NEAR 25 PCT WILL AGAIN LEAD TO ELEVATED WILD
FIRE RISK.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 PM EDT MON APR 23 2012
LOW PRESSURE SYSTEM CURRENTLY OVER NEW YORK WILL BE LOCATED OVER
WRN QUEBEC AT THE START OF THE PERIOD AND WILL PUSH N AND WEAKEN
WHILE THE UPPER RIDGE THAT HAS BEEN OVER THE WRN CONUS APPROACHES
THE WRN GREAT LKS. WEAK SHORTWAVE MOVING THROUGH THE NW FLOW ALOFT
ON TUES NIGHT INTO WED...WHILE ASSOCIATED SFC LOW SLIDES FROM THE
DAKOTAS TOWARDS THE LOWER GREAT LAKES. BROAD H850-500 WAA...Q-VECTOR
CONV...AND MOISTURE PUSHING IN SLOWLY TUES EVENING AND CONTINUES
THROUGH WED. ECMWF FARTHEST SW WITH THE BEST WAA...WHILE NAM/GFS/GEM
ALL TRY TO FOCUS A STRONGER AREA OF WAA OVER THE NRN CWA ON WED.
THESE DIFFERENCES LEAD TO SOME UNCERTAINTY ON THE EXACT LOCATION OF
THE RAIN. IN ADDITION...DRY AIR BELOW H800 WILL TRY TO LIMIT PCPN
CHANCES THROUGH MUCH OF THE OVERNIGHT HOURS OVER THE FAR WRN CWA.
ATMO DOESN/T REALLY SEEM TO MOISTEN UP UNTIL DAYLIGHT HOURS ON WED.
THIS DELAYED MOISTENING WILL LIMIT PCPN ACROSS THE REST OF THE CWA
FOR THE FIRST PART OF WED. HAVE TRIED TO PUT SOME TIMING IN FOR THIS
DRY AIR HOLDING OFF PCPN. EVEN WITH THE DRY AIR...SEEM TO HAVE
ENOUGH SIGNALS TO BUMP CHANCE POPS UP A LITTLE MORE...ESPECIALLY
OVER THE WRN CWA DURING THE DAY WED. THE INITIAL DRY AIR AND
POSITIONING OF THE PCPN PROVIDES A LITTLE TOO MUCH UNCERTAINTY TO
BUMP THEM UP TO LIKELY VALES.
MUCH STRONGER WAVE AND ASSOCIATED HEIGHT FALLS ARRIVES LATE WED
NIGHT AND THURS MORNING...WHICH BRING THE MUCH COOLER H850 TEMPS TO
THE AREA. THE COLD AIR ON THE BACK SIDE OF THE SYSTEM COULD LEAD TO
LK ENHANCED CLOUDS/PCPN LINGERING BEHIND THE WAVE INTO THURS
MORNING. NAM HOLDING ON TO THE LLVL MOISTURE THROUGH THE MORNING
HOURS BEFORE THE DRIER AIR AND SUBSIDENCE FROM THE HIGH PRESSURE
RIDGE START TO TAKE OVER. WITH THE NRLY FLOW OVER THE AREA DURING
THE MORNING...COMBINING WITH A BRIEF OVERLAP OF THE H850 TEMPS TO
-8C AND MOISTURE...THINK THERE WILL BE A BRIEF PERIOD OF STRONGER
RAIN/SNOW SHOWERS OVER THE NCNTRL UPSLOPE LOCATIONS MAINLY FROM
06-15Z. MAIN CONCERN WITH SNOW IS THAT THE LLVL TEMPS MIGHT NOT GET
COLD ENOUGH TO SUPPORT SNOW UNTIL THE BEST MOISTURE DEPARTS.
THUS...DELAYED THE SNOW CHANGE OVER TO OCCUR LATER IN THE NIGHT AND
DURING THE FIRST PART OF THURS MORNING. SNOW WILL OCCUR A LITTLE
EARLY OVER THE NW HALF OF THE CWA...BUT BOTH CASES WILL NEED A
LITTLE WHILE TO COOL CLOUD TEMPS AND GET ICE CRYSTALS BACK IN THE
CLOUD DUE TO THE DRY H750 AIR ARRIVING WED EVENING.
WITH THE HIGH PRESSURE RIDGE QUICKLY MOVING IN ON THURS AND LLVL
MOISTURE DEPARTING FOR ALL BUT FAR ERN UPPER MI...WILL DECREASE THE
CLOUDS ACROSS THE AREA EVEN THOUGH H850 TEMPS ARE STILL AROUND -6
OR -7C. COULD BE A LITTLE GUSTY WITH THE STRONG PRESSURE GRADIENT
LATE WED NIGHT INTO THURS. WITH THE COLD AIR ARRIVING AND H925
WINDS TO 30KTS...SHOULD SEE GUSTS IN THE 30-35MPH RANGE NEAR LK
SUPERIOR IN THE MORNING AND THEN DIMINISHING FORM WEST TO EAST
THROUGH THE DAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 635 PM EDT MON APR 23 2012
THE STRENGTHENING PRESSURE GRADIENT BETWEEN THE RETROGRADING
HIGH...AND ATLANTIC LOW PUSHING ACROSS THE LOWER GREAT LAKES THIS
EVENING WILL RESULT IN INCREASED NW WINDS AT CMX AND ESPECIALLY SAW.
VFR CONDITIONS SHOULD REMAIN THROUGH THE NEXT 24 HOURS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 PM EDT MON APR 23 2012
A STRONG LOW PRESSURE SYSTEM WILL MOVE NNE INTO THE ERN GREAT LAKES
BY THIS EVENING. THIS HAS RESULTED IN INCREASING NNW WINDS...UP TO
30KTS OVER ERN LK SUPERIOR WHICH WILL CONTINUE INTO TUESDAY MORNING.
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE UPPER LAKES ON WED WHILE
BEFORE STRONG HIGH PRESSURE BUILDS FROM CENTRAL CANADA INTO THE
GREAT LAKES WEDNESDAY NIGHT INTO THURSDAY. THE STRONG GRADIENT
BETWEEN THESE SYSTEMS WILL LEAD TO NORTHERLY GUSTS UP TO 30KTS
OVER CENTRAL AND EASTERN LAKE SUPERIOR WEDNESDAY NIGHT INTO THURSDAY
MORNING. A FEW GALE FORCE GUSTS TO 35KTS ARE ALSO POSSIBLE DURING
THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MIZ006>008-
013>015-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
EXTENDED...JMW
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
417 PM EDT MON APR 23 2012
.SYNOPSIS...
ISSUED AT 414 PM EDT MON APR 23 2012
WV IMAGERY AND RUC ANALYSIS INDICATED A HIGH AMPLITUDE PATTERN WITH
A MID/UPPER LEVEL RIDGE OVER THE WRN CONUS AND A TROUGH OVER THE
EAST RESULTING IN CONFLUENT NRLY FLOW THROUGH THE UPPER GREAT LAKES.
AN UPSTREAM SHORTWAVE TROUGH MOVING INTO NRN MANITOBA SUPPORTED AN
EXTENSIVE AREA OF CLOUDS AND A FEW LIGHT SHOWERS. AT THE SFC...THE
GRADIENT WAS INCREASING BTWN LOW PRESSURE OVER ERN NY AND A RIDGE
OVER THE UPPER MS VALLEY.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 414 PM EDT MON APR 23 2012
AS THE SHORTWAVE TROUGH MOVES TOWARD THE AREA...EXPECT MID CLOUDS TO
INCREASE LATE TONIGHT. THE GFS WAS MORE AGGRESSIVE WITH 290K
ISENTROPIC LIFT AND PCPN POTENTIAL COMPARED TO THE REST OF THE
MODELS. SO...GIVEN THE LACK OF MOISTURE AVBL AND THE RELATIVELY
MODEST DYNAMICS...ONLY SLIGHT CHANCE POPS WERE INCLUDED OVER WEST.
SOME INLAND TEMPS MAY FALL TO NEAR FREEZING BUT SOUNDINGS SUGGEST
THAT PCPN TYPE WOULD BE RAIN.
RELATIVELY POOR RH RECOVERY IS EXPECTED OVERNIGHT ACROSS THE
AREA...BUT MOST SIGNIFICANTLY OVER THE EASTERN HALF. EVEN WITH THE
LOSS OF DAYTIME HEATING/MIXING 9250 MB WINDS IN THE 40 TO 45 KT
RANGE...FROM 03Z TO 15Z TUESDAY. AFTER AREAS OF CLOUDS WITH THE
SHRTWV MOVE OUT BY AFTERNOON...SUNSHINE AND MIXING SHOULD AGAIN DROP
DEWPOINTS BLO GUIDANCE TO AROUND 20F. WITH TEMPERATURES INTO THE MID
AND UPPER 50S...RH VALUES NEAR 25 PCT WILL AGAIN LEAD TO ELEVATED WILD
FIRE RISK.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 414 PM EDT MON APR 23 2012
LOW PRESSURE SYSTEM CURRENTLY OVER NEW YORK WILL BE LOCATED OVER
WRN QUEBEC AT THE START OF THE PERIOD AND WILL PUSH N AND WEAKEN
WHILE THE UPPER RIDGE THAT HAS BEEN OVER THE WRN CONUS APPROACHES
THE WRN GREAT LKS. WEAK SHORTWAVE MOVING THROUGH THE NW FLOW ALOFT
ON TUES NIGHT INTO WED...WHILE ASSOCIATED SFC LOW SLIDES FROM THE
DAKOTAS TOWARDS THE LOWER GREAT LAKES. BROAD H850-500 WAA...Q-VECTOR
CONV...AND MOISTURE PUSHING IN SLOWLY TUES EVENING AND CONTINUES
THROUGH WED. ECMWF FARTHEST SW WITH THE BEST WAA...WHILE NAM/GFS/GEM
ALL TRY TO FOCUS A STRONGER AREA OF WAA OVER THE NRN CWA ON WED.
THESE DIFFERENCES LEAD TO SOME UNCERTAINTY ON THE EXACT LOCATION OF
THE RAIN. IN ADDITION...DRY AIR BELOW H800 WILL TRY TO LIMIT PCPN
CHANCES THROUGH MUCH OF THE OVERNIGHT HOURS OVER THE FAR WRN CWA.
ATMO DOESN/T REALLY SEEM TO MOISTEN UP UNTIL DAYLIGHT HOURS ON WED.
THIS DELAYED MOISTENING WILL LIMIT PCPN ACROSS THE REST OF THE CWA
FOR THE FIRST PART OF WED. HAVE TRIED TO PUT SOME TIMING IN FOR THIS
DRY AIR HOLDING OFF PCPN. EVEN WITH THE DRY AIR...SEEM TO HAVE
ENOUGH SIGNALS TO BUMP CHANCE POPS UP A LITTLE MORE...ESPECIALLY
OVER THE WRN CWA DURING THE DAY WED. THE INITIAL DRY AIR AND
POSITIONING OF THE PCPN PROVIDES A LITTLE TOO MUCH UNCERTAINTY TO
BUMP THEM UP TO LIKELY VALES.
MUCH STRONGER WAVE AND ASSOCIATED HEIGHT FALLS ARRIVES LATE WED
NIGHT AND THURS MORNING...WHICH BRING THE MUCH COOLER H850 TEMPS TO
THE AREA. THE COLD AIR ON THE BACK SIDE OF THE SYSTEM COULD LEAD TO
LK ENHANCED CLOUDS/PCPN LINGERING BEHIND THE WAVE INTO THURS
MORNING. NAM HOLDING ON TO THE LLVL MOISTURE THROUGH THE MORNING
HOURS BEFORE THE DRIER AIR AND SUBSIDENCE FROM THE HIGH PRESSURE
RIDGE START TO TAKE OVER. WITH THE NRLY FLOW OVER THE AREA DURING
THE MORNING...COMBINING WITH A BRIEF OVERLAP OF THE H850 TEMPS TO
-8C AND MOISTURE...THINK THERE WILL BE A BRIEF PERIOD OF STRONGER
RAIN/SNOW SHOWERS OVER THE NCNTRL UPSLOPE LOCATIONS MAINLY FROM
06-15Z. MAIN CONCERN WITH SNOW IS THAT THE LLVL TEMPS MIGHT NOT GET
COLD ENOUGH TO SUPPORT SNOW UNTIL THE BEST MOISTURE DEPARTS.
THUS...DELAYED THE SNOW CHANGE OVER TO OCCUR LATER IN THE NIGHT AND
DURING THE FIRST PART OF THURS MORNING. SNOW WILL OCCUR A LITTLE
EARLY OVER THE NW HALF OF THE CWA...BUT BOTH CASES WILL NEED A
LITTLE WHILE TO COOL CLOUD TEMPS AND GET ICE CRYSTALS BACK IN THE
CLOUD DUE TO THE DRY H750 AIR ARRIVING WED EVENING.
WITH THE HIGH PRESSURE RIDGE QUICKLY MOVING IN ON THURS AND LLVL
MOISTURE DEPARTING FOR ALL BUT FAR ERN UPPER MI...WILL DECREASE THE
CLOUDS ACROSS THE AREA EVEN THOUGH H850 TEMPS ARE STILL AROUND -6
OR -7C. COULD BE A LITTLE GUSTY WITH THE STRONG PRESSURE GRADIENT
LATE WED NIGHT INTO THURS. WITH THE COLD AIR ARRIVING AND H925
WINDS TO 30KTS...SHOULD SEE GUSTS IN THE 30-35MPH RANGE NEAR LK
SUPERIOR IN THE MORNING AND THEN DIMINISHING FORM WEST TO EAST
THROUGH THE DAY.
&&
FOR THE EXTENDED...
MODELS ARE STILL IN FAIRLY GOOD AGREEMENT IN THE PLACEMENT OF A
MID/UPPER LEVEL RIDGE OVER THE PLAINS THROUGH THE DAY FRIDAY...WITH
THE ASSOCIATED SURFACE HIGH PRESSURE DOMINATING THE UPPER GREAT
LAKES REGION THROUGH SATURDAY. THIS WILL KEEP DRY WEATHER WITH
PREDOMINATE LIGHT N/NERLY WINDS THROUGH THIS TIME PERIOD.
SUNNY/PARTLY CLOUDY SKIES WILL KEEP TEMPERATURES FAIRLY STEADY /AT
OR SLIGHTLY BELOW NORMAL/...WITH COOLEST TEMPERATURES NEAR LAKE
SUPERIOR DUE TO NORTHERLY WINDS OFF THE LAKE.
MODEL CONSENSUS ALSO SHOWS A SHORTWAVE DEVELOPING ON THE BACKSIDE OF
THE RIDGE...HOWEVER DISAGREEMENTS COME IN TO PLAY ON THE PATH THIS
SHORTWAVE WILL TAKE. GFS AND GEM SOLUTIONS HAVE THE SHORTWAVE
DEVELOPING OVER THE PLAINS ON SATURDAY...THEN GETTING PUSHED TO THE
SOUTHEAST UNDER THE INFLUENCE OF THE HIGH PRESSURE RIDGE AND DRY AIR
ALREADY IN PLACE. THIS SOLUTION SEEMS THE MOST REASONABLE. ECMWF
SOLUTION ON THE OTHER HAND CONTINUES TO BE MORE AGGRESSIVE WITH THIS
SYSTEM...MOVING IT NORTHEAST ALONG THE BACKSIDE OF THE RIDGE AND
REACHING THE UPPER GREAT LAKES BY SATURDAY AFTERNOON. WITH THE
GFS/GEM...UPPER MI SHOULD REMAIN DRY. HOWEVER WILL KEEP SLIGHT
CHANCES NEAR THE WI BORDER SATURDAY AFTERNOON...SPREADING FURTHER
INLAND SATURDAY NIGHT AND SUNDAY TO ACCOUNT FOR ECMWF SOLUTION. WITH
THE INCREASE IN CLOUD COVER ASSOCIATED WITH THIS SYSTEM...EXPECT LOW
TEMPERATURES SAT NIGHT TO BE SLIGHTLY WARMER THAN PREVIOUS...BUT
STILL HOVERING ON THE FREEZING LINE...SO SNOW COULD MIX IN WITH RAIN
IN AFFECTED AREAS. PRECIP SHOULD DISSIPATE BY SUNDAY NIGHT AS
SHORTWAVE MOVES TO THE SOUTHEAST AND HIGH PRESSURE BEGINS TO BUILD
IN FROM CANADA THROUGH THE DAY MONDAY.
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 137 PM EDT MON APR 23 2012
THE STRENGTHENING PRESSURE GRADIENT BETWEEN THE RETROGRADING
HIGH...AND ATLANTIC LOW PUSHING ACROSS THE LOWER GREAT LAKES THIS
EVENING WILL RESULT IN INCREASED NW WINDS AT CMX AND ESPECIALLY SAW.
VFR CEILINGS AND VIS SHOULD REMAIN THROUGH THE NEXT 24 HOURS.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 PM EDT MON APR 23 2012
A STRONG LOW PRESSURE SYSTEM WILL MOVE NNE INTO THE ERN GREAT LAKES
BY THIS EVENING. THIS HAS RESULTED IN INCREASING NNW WINDS...UP TO
30KTS OVER ERN LK SUPERIOR WHICH WILL CONTINUE INTO TUESDAY MORNING.
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE UPPER LAKES ON WED WHILE
BEFORE STRONG HIGH PRESSURE BUILDS FROM CENTRAL CANADA INTO THE
GREAT LAKES WEDNESDAY NIGHT INTO THURSDAY. THE STRONG GRADIENT
BETWEEN THESE SYSTEMS WILL LEAD TO NORTHERLY GUSTS UP TO 30KTS
OVER CENTRAL AND EASTERN LAKE SUPERIOR WEDNESDAY NIGHT INTO THURSDAY
MORNING. A FEW GALE FORCE GUSTS TO 35KTS ARE ALSO POSSIBLE DURING
THIS TIME.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
RED FLAG WARNING UNTIL 8 PM EDT THIS EVENING FOR MIZ006>008-
013>015-085.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLB
SHORT TERM...JLB
LONG TERM...SRF
EXTENDED...JMW
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
926 PM CDT TUE APR 24 2012
.UPDATE...
ISSUED AT 918 PM CDT TUE APR 24 2012
GOING FORECAST LOOKS ON TRACK. STILL SOME CONCERN THERE COULD BE
SOME PRECIP MOVING INTO CENTRAL MISSOURI FROM THE WEST BEFORE
SUNRISE...BUT 00Z NAM IS TRICKLING IN ALREADY AND IT`S KEEPING THE
PRECIP WELL WEST OF COLUMBIA. RUC AND HRRR ARE LIKEWISE DRY ACROSS
OUR CWFA...THOUGH THE HRRR IS MUCH MORE AGGRESSIVE IN DEVELOPING
THUNDERSTORMS OVER NEBRASKA NEAR THE 850MB FRONT AND ADVECTING
THEM SOUTHEAST ACROSS MISSOURI. THE HRRR TENDS TO BE A LITTLE OVER
ZEALOUS AT TIMES...SO WILL JUST KEEP THE SLIGHT CHANCE POPS IN
CENTRAL MO FOR NOW.
CARNEY
&&
.SHORT TERM...
ISSUED AT 345 PM CDT TUE APR 24 2012
(TONIGHT)
THE WRMFNT HAS LIFTED NWD THRU MOST OF THE CWA TODAY. THIS FNT WILL
SINK SWWD SLIGHTLY THIS EVENING WITH LOSS OF HEATING. EXPECT WINDS
TO DIMINISH SOMEWHAT TONIGHT. WRN AND SWRN PORTIONS OF THE CWA WILL
STILL HAVE SW FLOW THRU MUCH OF THE NIGHT AND HAVE TRENDED TWD THE
WARMER GUIDANCE FOR TONIGHT.
MAIN QUESTION FOR TONIGHT IS POPS. THE GFS HAS WIDESPREAD QPF ACROSS
MUCH OF THE SRN PORTIONS OF MO AND IL FOR TONIGHT. BELIEVE MUCH OF
THIS IS DUE TO TEMP FALLING TO REACH THE DEWPOINT AT/NEAR THE SFC
BASED ON SOUNDINGS. HOWEVER...THE NAM/LOCAL WRF SUGGEST ELEVATED
INSTABILITY WITH JUST ENUF MOISTURE THAT ISOD TO WDLY SCT TSRA WILL
BE POSSIBLE DURING THE PRE DAWN HOURS. THE BETTER MOISTURE IS
FURTHER S AND THE POPS THAT WERE ADDED ARE MAINLY TO COVER
DIFFERENCES IN PRECIP PLACEMENT.
TRUETT
&&
.LONG TERM...
ISSUED AT 345 PM CDT TUE APR 24 2012
(WEDNESDAY-THURSDAY)
STILL TOUGH TO DETERMINE CONVECTIVE POTENTIAL ON WEDNESDAY. IT
WOULD APPEAR THAT FOR MOST OF THE DAY THE THREAT WILL COME FROM
HIGH BASED CONVECTION DUE TO LARGE SCALE WAA...WITH LOW LEVELS
REMAINING STRONGLY CAPPED DUE TO STRONGLY MIXED EML. WHILE THE
WAA-INDUCED CONVECTION WILL BE MOSTLY PROBABLE EAST OF THE
MISSISSIPPI RIVER DURING THE AFTERNOON AND EARLY EVENING...GETTING THE
FEELING THAT FOR MOST OF THE AREA WE WILL BE IN A WAITING MODE TO
SEE IF CONVERGENCE ALONG THE COLD FRONT LATER IN THE AFTERNOON AND
ESPECIALLY OVERNIGHT WILL BE ABLE TO OVERCOME THE CAP. MODELS DO
NOT SEEM OVERLY OPTIMISTIC ABOUT SURFACE BASED CONVECTION FIRING
WEST OF THE MISSISSIPPI...AND GIVEN HOW DRY THE AMS CURRENTLY IS
OVER MOST OF THE PLAINS ITS CERTAINLY POSSIBLE THAT MODELS ARE TOO
HIGH WITH THEIR LOW LEVEL MOISTURE FORECASTS AND RESULTANT CAPE.
HOWEVER DONT WANT TO TOTALLY GIVE UP ON PRECIP AT THIS POINT IN
TIME WITH SURFACE TEMPERATURES PUSHING INTO THE LM80S. SO...POPS
FOR WED NIGHT WILL RANGE FROM LOW CHANCE OVER MID MO...TO AROUND
50% OVER S IL.
TEMPERATURES WILL BE WELL ABOVE NORMAL ON WEDNESDAY...AND EXACTLY
HOW WARM WILL ULTIMATELY DEPEND ON CLOUD COVER. 80S APPEAR LIKELY
IN MOST AREAS...AND A FEW SPOTS IN MID MO SHOULD BE WITHIN A FEW
DEGREES OF THEIR RECORD HIGHS FOR APRIL 25TH (COU....89 IN 1986).
ALTHOUGH SHORT RANGE MODELS VARY IN SPECIFICS...THEY ALL INDICATE
THAT FRONTAL BOUNDARY WILL BE SHIFTING INTO S MO/S IL ON THURSDAY.
MODELS ARE ONLY FORECASTING MODEST OVERRRUNNING DURING THE
DAY...SO WOULD THINK THAT GREATEST PRECIP THREAT WOULD BE OVER OUR
FAR S COUNTIES...ASSOCIATED WITH THE LOW LEVEL CONVERGENCE NEAR
THE FRONT. GIVEN THE FACT THAT OVER THE PAST FEW DAYS THE SHORT
RANGE MODELS HAVE SLOWED THE FRONTS SOUTHWARD PROGRESSION AND HAVE
INITIATED RETURN FLOW A BIT MORE RAPIDLY WILL KEEP SOME LOW POPS
GOING N OF THE FRONT...OVER THE CENTRAL THIRD OF OUR CWA.
(THURSDAY NIGHT-TUESDAY)
UNSETTLED AND WET IS PROBABLY THE PHRASE THAT DESCRIBES THE UPCOMING
WEATHER FOR THE END OF THIS WORK WEEK. WITH THE APPROACH OF FIRST
SHORTWAVE OVER THE PLAINS ALL MODELS RAMP UP OVERRUNNING THURSDAY
NIGHT...AND AS A RESULT HAVE INCREASED POPS INTO THE LIKELY RANGE
WHERE IT APPEARS LOW LEVEL FORCING WILL BE MAXIMIZED...FROM CENTRAL
AND NE MO TO NEAR THE MISSISSIPPI RIVER. FAIRLY HIGH POPS WILL
CONTINUE FRIDAY...AND ESPECIALLY FRIDAY NIGHT...AS THE UPPER RIDGE
PUSHES EAST AND AFOREMENTIONED SHORTWAVE MOVES INTO THE MID
MISSISSIPPI VALLEY.
SEVERE WEATHER WILL CERTAINLY BE POSSIBLE IN THE THURSDAY
NIGHT-FRIDAY NIGHT TIME FRAME...WITH ELEVATED SEVERE STORM THREAT
(MAINLY HAIL) DURING THE FIRST PART OF THE PERIOD FOLLOWED BY A MORE
SURFACED-BASED THREAT WHICH WOULD INCLUDE THE ENTIRE SEVERE WEATHER
SPECTRUM BY LATE FRIDAY AND FRIDAY NIGHT AS STRONG WAVES PROPAGATES
ALONG THE STALLED BOUNDARY. SOME LOCALIZED HYDRO PROBLEMS WILL
MAY ALSO BE POSSIBLE.
TEMPERATURES ARE GOING TO BE VERY TRICKY ON FRIDAY...DEPENDING ON
THE ACTUAL POSITION OF THE FRONT. ITS CERTAINLY POSSIBLE THAT
NORTHERN PARTS OF OUR AREA MAY STRUGGLE TO REACH THE LOWER
50S...WHILE OUR FAR S COUNTIES COULD BE IN THE 70S.
RAIN THREAT SHOULD DIMINISH SATURDAY AND SATURDAY NIGHT AS FRONTAL
BOUNDARY OOZES BACK TO THE SOUTH...AND THEN IT LOOKS LIKE WE MAY
SQUEEZE OUT A COUPLE OF DRY DAYS ON SUNDAY AND MONDAY. HOWEVER...
THE FRONT...AND A THREAT OF SHOWERS/THUNDERSTORMS...WILL RETURN BY
TUESDAY. WITH THE CWA REAMING N OF THE FRONT TEMPERATURES IN THE
SATURDAY-TUESDAY TIME FRAME SHOULD BE QUITE COOL...SOME 5 TO 15
DEGREES BELOW NORMAL.
&&
.AVIATION...
ISSUED AT 604 AM CDT TUE APR 24 2012
VFR CONDITIONS ARE EXPECTED. MID LEVEL CLOUD DECK WILL CONTINUE TO
CASCADE SOUTH/SOUTHEAST ACROSS THE FORECAST AREA AS A WARM FRONT
TAKES SHAPE. WILL LIKELY SEE ISO/SCT SHOWERS/STORMS DEVELOP BY
AFTERNOON. WIND WILL GENERALLY BACK FROM SOUTHWEST TO THE
SOUTHEAST THROUGH THE FORECAST.
SPECIFICS FOR KSTL...
VFR CONDITIONS EXPECTED. MID LEVEL CLOUDS WITH ISO/SCT
SHOWERS/STORMS WILL DEVELOP BY NOON. COVERAGE DICTATES ONLY A
VCSH. WIND TO BACK FROM SOUTHWEST TO SOUTHEAST.
CVKING
&&
.AVIATION...
ISSUED AT 604 AM CDT TUE APR 24 2012
VFR CONDITIONS ARE EXPECTED. MID LEVEL CLOUD DECK WILL CONTINUE TO
CASCADE SOUTH/SOUTHEAST ACROSS THE FORECAST AREA AS A WARM FRONT
TAKES SHAPE. WILL LIKELY SEE ISO/SCT SHOWERS/STORMS DEVELOP BY
AFTERNOON. WIND WILL GENERALLY BACK FROM SOUTHWEST TO THE
SOUTHEAST THROUGH THE FORECAST.
SPECIFICS FOR KSTL...
VFR CONDITIONS EXPECTED. MID LEVEL CLOUDS WITH ISO/SCT
SHOWERS/STORMS WILL DEVELOP BY NOON. COVERAGE DICTATES ONLY A
VCSH. WIND TO BACK FROM SOUTHWEST TO SOUTHEAST.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
615 PM CDT Tue Apr 24 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
In the short term, primary concerns remain with slight convective
chances through Wednesday along with temperatures.
This afternoon, pesky altocumulus and cirrostratus have limited the
upwards extend of temperatures to some degree. However, many areas
will still climb nearly 10-15 degrees above seasonal normals. The
warmest temperatures this afternoon have been located over central
Kansas and southern Nebraska where many locations are now in the
middle 90s. This airmass will gradually move eastward during the
overnight hours.
Tonight: 18z NAM, high-res WRF and HRRR continue to generate isolated to
scattered showers or thunderstorms late tonight across central and
southeastern Kansas along with western Missouri. This activity seems
to be tied to a weak shortwave expected to cross eastward out of the
central Rockies overnight. A slightly amplified low level jet will
push an additional surge of mid-level moisture eastward, with an
increase in elevated instability above 600 mb. An incredibly dry
lower half of the troposphere should limit widespread precipitation,
but if a thunderstorm could form would have to watch for the
potential for some sort of stronger wind gust or heat burst.
Wednesday: GFS which has handled today`s cloud cover adequately well
is less bullish with mid-level cloud cover with EML shifting further
east. Mid-level AC may fester Wednesday morning in central Missouri,
delaying the rapid warmup. However, the remainder of the CWA will be highly
capped, allowing for a significant warmup to near record levels in some
locations. Fast moving shortwave trough will race into the western
Great Lakes late Wednesday afternoon with a ill-defined surface
trough over northern Missouri. Models still point to little in the
way of development along this boundary as best dynamics are focused
in the Great Lakes with the progressive shortwave. There may be
enough surface convergence for a slightly higher chance for late
afternoon or evening thunderstorms in northeastern Missouri.
Wednesday night and Thursday: Models have again shifted the surface
boundary a bit further south into central Missouri Wednesday night,
with an slightly stronger influence from cooler Canadian air
possible. Northeast winds should hold temperatures still above
normal, but will lower temperatures a few degrees Thursday. By
Thursday night, the next round of warm advection precipitation
should begin as the next upper low begins to eject out of the
southwestern United States.
Dux
Medium Range (Friday through Tuesday)...
A quick deamplification of the upper pattern will bring about a more
progressive and stormier pattern for the extended period. As upper
ridging breaks down over the Midwest, a weak negatively-tilted
shortwave will eject into the Plains early Friday, and quickly
deamplify as it becomes absorbed by mean Great Lakes troughing on
Saturday. The result will be a quickly filling surface low that is
forecast to track across southern or central Missouri Friday night.
Going off the more stable GFS solution suggests a more progressive
and southerly forecast track that keeps much of the forecast area in
the cool sector on Friday. This solution is backed up by the latest
NAM which is even further south. This also sets up a tight
baroclinic region marking the difference between temperatures near
50 across the north and in the mid 70s south. Bulk of precipitation
Friday and Friday night will be focused near and just north of this
boundary, which looks to set up near or just south of the US 50
corridor. Can`t rule out some elevated small hailers on Friday but
any appreciable severe threat will remain south of the boundary, and
capping may keep that threat to a minimum.
Continued to lean toward the more progressive GFS solution for
Saturday and Sunday so brought PoPs lower than consensus numbers for
this period. In continued quasizonal flow, the next wave to impact
the region will arrive Monday night and Tuesday. Surface baroclinic
region will remain south of the region through early next week
maintaining below average temperatures through the period.
Hawblitzel
&&
.CLIMATE...
Record highs for Wednesday:
CITY...........NORMAL HIGH........RECORD HIGH
KANSAS CITY....69 DEGREES.........91 IN 1989
ST. JOESPH.....68 DEGREES.........92 IN 1989
DUX
&&
.AVIATION...
For the 00Z TAFS, VFR conditions are expected through the entire
period. Scattered mid level clouds should persist overnight with
light southerly winds. Winds will veer to the southwest mid to late
Wednesday morning with mid level clouds possibly increasing a bit
through the day. A weak boundary will drift southward late in the
valid period and should veer winds more westerly. This boundary may
also help trigger a few showers or storms but confidence on this is
very low given the strong cap in place over the region at the time.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
609 PM CDT TUE APR 24 2012
...MESOSCALE CONVECTIVE DISCUSSION...
...UPDATE TO AVIATION...
.UPDATE...
WATER VAPOR IMAGERY AND THE PROFILER NETWORK INDICATE SHORT WAVE
ENERGY EXTENDING FROM CENTRAL NEBRASKA INTO EASTERN COLORADO.
SHORT RANGE MODELS ALL STRENGTHEN A LOW LEVEL JET STARTING THIS
EVENING...AND HAVE THE NOSE OF THIS JET STRONGLY VEERED INTO THE
OZARKS BY LATE TONIGHT. BOTH THE 18Z NAM AND GFS BREAK OUT
CONVECTION SOMEWHERE ACROSS EASTERN KANSAS AND/OR THE MISSOURI
OZARKS...WITH THE 21Z RUC ALSO SHOWING AT LEAST A HINT OF QPF AT
09Z.
VISIBLE SATELLITE IMAGERY AND RADAR COMPOSITES CONTINUE TO SHOW
SIGNS OF ACCAS/STEEP MID LEVEL LAPSE RATES ALL THE WAY BACK INTO
WESTERN KANSAS. AS THE LOW LEVEL JET STRENGTHENS LATER
TONIGHT...THE QUESTION BECOMES WHETHER OR NOT ELEVATED PARCELS CAN
TAP INTO THESE LAPSE RATES. ONE HURDLE TO OVERCOME MAY BE SOME MID
LEVEL DRY AIR AS UPSTREAM SOUNDINGS FROM THIS MORNING WERE RATHER
DRY. ADDITIONALLY...LIFTING PARCELS FROM VARIOUS LEVELS OFF OF
THE 18Z NAM INDICATES AT LEAST MODEST INHIBITION.
THE 00Z SOUNDINGS FROM UPSTREAM OFFICES WILL BE OF GREAT HELP IN
DETERMINING CONVECTIVE POTENTIAL LATER TONIGHT. GIVEN THE
UNCERTAINTY...THE CURRENT FORECAST HAS THIS COVERED WELL FOR NOW
WITH 20 POPS.
SCHAUMANN
&&
.DISCUSSION...
WERE WELL ON OUR WAY TO ANOTHER WONDERFUL SPRING DAY ACROSS THE
REGION. BREEZY SOUTHWESTERLY WINDS AND CLEAR SKIES CONTINUE TO PAVE
THE WAY FOR WARM TEMPERATURES THIS AFTERNOON. THROUGH 3 PM...TEMPS
WERE WELL IN THE 70S ACROSS THE REGION WITH HIGHS IN THE LOWER 80S
EXPECTED. THROUGH NOON...A GOOD STREAM OF UPPER LEVEL
STRATOCUMULUS CONTINUES TO MARCH IN FROM THE NORTH ACROSS CENTRAL
MISSOURI...IN RESPONSE TO THE CENTRAL U.S. REMAINING WELL ROOTED
WITHIN THE LEEWARD SIDE OF THE UPPER LEVEL TROUGH AXIS SITUATED
OVER THE INTER-MOUNTAIN WEST.
UNFORTUNATELY...OUR WARM SUNNY WEATHER WILL NOT LAST FOR LONG AS A
MORE UNSETTLED WEATHER PATTERN IS ON THE HORIZON...BEGINNING WITH A
SMALL CHANCE FOR SOME ISOLATED SHOWERS AND THUNDERSTORMS EARLY
TOMORROW MORNING AND THEN CONTINUAL CHANCES OF PRECIP FROM WEDNESDAY
NIGHT THROUGH THE WEEKEND AS A COLD FRONT SETS UP FROM WEST TO EAST
ACROSS THE LOWER MISSOURI RIVER VALLEY.
REGARDING TONIGHT...AS THE UPPER LEVEL LOW OVER NEW ENGLAND
CONTINUES TO LIFT NORTH/NORTHEAST TODAY...THE RIDGE OVER THE WEST
WILL CONTINUE TO TRACK EASTWARD AND SLOWLY DECREASE IN
AMPLITUDE...WITH SMALL DISTURBANCES RIDING ALONG THE UPPER LEVEL
FLOW. BOTH THE 12Z RUNS OF THE GFS AND NAM HINT AT CONVECTION
OCCURRING OVER THE FOUR STATES REGION AFTER MIDNIGHT THROUGH DAY
BREAK...WHILE THE EURO CONTINUES TO HOLD OFF ANY DEVELOPMENT. THERE
REMAINS SOME CONCERN WITH HOW MUCH MOISTURE RETURN WE CAN GET THIS
AFTERNOON AND TONIGHT AS WELL AS HOW MUCH FORCING...RUC AND NAM
BUFKIT SOUNDINGS SHOW A WEAK EML WILL LIKELY REMAIN OVER
SOUTHWESTERN MISSOURI OVERNIGHT...WITH ANY MOISTURE REMAINING IN THE
MID LEVELS. WOULD LIKE TO SEE A BETTER LOW LEVEL JET NOSE INTO
SOUTHWESTERN MISSOURI...WITH GUIDANCE FOR NOW HINTING AT THE 850MB
JET NOSING IN NORTHWEST OF THE CWA. HOWEVER...GIVEN THE TIME OF YEAR
AND AVAILABLE MID-LEVEL MOISTURE...A FEW ISOLATED SHOWERS OR
THUNDERSTORMS CANNOT BE RULED OUT OVER PORTIONS OF THE OUTLOOK AREA
IN THE EARLY MORNING AS THAT 500MB DISTURBANCE MOVES OVER THE AREA.
THE REST OF WEDNESDAY LOOKS TO BE FAIRLY PLEASANT...WITH HIGHS
FORECAST IN THE UPPER 80S WITH MOSTLY CLEAR SKIES AND SOUTHWEST
WINDS PICKING UP AGAIN IN THE AFTERNOON. HOWEVER...WEDNESDAY NIGHT
THROUGH THURSDAY MORNING A COLD FRONT DROPPING OUT OF THE NORTH WILL
BRING OUR NEXT CHANCE FOR A PROLONGED PERIOD OF PRECIPITATION. A
500MB SHORTWAVE WILL BEGIN TO DIG OFF THE SOUTHERN CALIFORNIA COAST
WHILE THE LOW OVER THE NORTHEAST LIFTS ACROSS MAINE AND NOVA SCOTIA.
THIS WILL RESULT IN NEARLY ZONAL FLOW FROM THE HIGH PLAINS THROUGH
THE EAST COAST FROM THURSDAY NIGHT THROUGH FRIDAY. THIS WILL CAUSE
A COLD FRONT TO SAG SOUTH ACROSS CENTRAL MISSOURI. THIS FRONT WILL
REMAIN A FOCAL POINT FOR NEARLY DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS FROM THURSDAY THROUGH THE WEEKEND.
AS FOR SEVERE WEATHER...BEST CHANCES LOOK TO OCCUR ON THURSDAY
EVENING THROUGH FRIDAY AS A DEEPENING SURFACE LOW BEGINS TO TRACK
ACROSS CENTRAL MISSOURI. SOUTH WINDS WILL INCREASE DEW POINTS ACROSS
THE REGION WITH DECENT DEEP LAYER SHEAR VALUES. COULD NOT RULE OUT
SOME STRONG TO SEVERE THUNDERSTORMS DEVELOPING ALONG THE FRONTAL
BOUNDARY AS IT LIFTS BACK NORTH WITH HAIL AND STRONG WINDS THE
PRIMARY THREATS.
FOR THE WEEKEND...TEMPS WILL COOL CONSIDERABLY AS A SHALLOW ARCTIC
HIGH SETTLES BACK OVER THE MISSOURI RIVER VALLEY...DROPPING HIGHS
BACK INTO THE MID TO UPPER 50S AND LOWS INTO THE 40S.
KURTZ
&&
.AVIATION...
THE MAIN AVIATION CONCERN FROM TONIGHT INTO WEDNESDAY MORNING WILL
BE STRONG LOW LEVEL WIND SHEAR. THERE IS A SLIGHT CHANCE FOR A FEW
THUNDERSTORMS LATE TONIGHT. GIVEN SUCH LOW CONFIDENCE...THERE WAS
NO MENTION OF THUNDERSTORMS IN THE TAFS. SHORT TERM TRENDS WILL BE
MONITORED CLOSELY FOR THUNDERSTORM POTENTIAL...WITH AMENDMENTS TO
THE TAFS REQUIRED IF CONFIDENCE INCREASES IN THIS SCENARIO. IF
THUNDERSTORMS DO MANAGE TO DEVELOP...THEY WOULD QUICKLY SHIFT EAST
OF THE AREA BY LATE WEDNESDAY MORNING. MEANWHILE...BRISK AND GUSTY
SOUTHWEST WINDS WILL ONCE AGAIN DEVELOP BY LATE WEDNESDAY MORNING.
SCHAUMANN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
633 PM CDT TUE APR 24 2012
.AVIATION...00Z KGRI TAF. VFR CONDITIONS TO CONTINUE THROUGH THE
NEXT 24 HOURS. HIGH LEVEL CLOUDS WILL INCREASE DURING THE DAY
WEDNESDAY AS SURFACE WINDS BECOME MORE ESTABLISHED FROM THE NORTH.
VISIBILITY RESTRICTIONS ARE NOT ANTICIPATED THROUGH THE NEXT 24 HOURS.
&&
.PREV DISCUSSION... /ISSUED 244 PM CDT TUE APR 24 2012/
SHORT TERM...TUESDAY NIGHT THROUGH WEDNESDAY.
UPPER LEVEL ANALYSIS INDICATES A STRONG UPPER LEVEL RIDGE HAS BUILT
IN ACROSS THE WESTERN HALF OF THE UNITED STATES. ALONG THIS RIDGE
AXIS...A SURGE OF VERY WARM 850 MB TEMPS NEAR 28 TO 30 DEGREES
CELSIUS HAS CONTINUED TO TRAVERSE NORTHWARD. AT THE SURFACE...A LOW
PRESSURE SYSTEM PUSHING ACROSS THE NORTHERN PLAINS HAS ALLOWED A
TROUGH AXIS TO MOVE THROUGH THE CENTRAL PLAINS.
STRONG BOUNDARY LAYER MIXING AND INCREASED WINDS MAINLY ACROSS THE
SOUTHERN PORTIONS OF THE FORECAST AREA WILL CONTINUE TO ALLOW
TEMPERATURES TO CLIMB THIS AFTERNOON. SEVERAL SITES ACROSS THE ARE
HAVE ALREADY HIT 90 DEGREES AND COULD EASILY INCREASE A FEW MORE
DEGREES. WITH SUCH WARMING TODAY...AND SEVERAL SITES EASILY
REALIZING CONVECTIVE TEMPS...WE COULD SEE SCATTERED CUMULUS DEVELOP
ACROSS THE REGION THIS AFTERNOON AND MAYBE EVEN A THUNDERSTORM OR
TWO. RUC AND LAPS MODELS BOTH INDICATE SOME INSTABILITY ACROSS THE
REGION.
FOR WEDNESDAY...THE SURFACE LOW PRESSURE SYSTEM IS EXPECTED TO SHIFT
JUST NORTHEAST OF THE REGION...DRAGGING A COLD FRONT ACROSS THE
FORECAST AREA. BY AFTERNOON...WINDS ARE EXPECTED TO SHIFT TO THE
NORTHWEST AND EVENTUALLY NORTH. 850 TEMPERATURES LOOK TO REMAIN
QUITE WARM AGAIN ON WEDNESDAY. WITH MODEL SOUNDINGS INDICATING
PLENTY OF BOUNDARY LAYER MIXING...DO NOT SEE A REASON WHY WEDNESDAY
WILL NOT BE AS WARM AS TODAY.
LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY. FRONTAL BOUNDARY
WHICH PUSHES SOUTH DURING THE DAY WEDNESDAY STALLS ACROSS NORTH
CENTRAL KANSAS WEDNESDAY NIGHT. MODELS...ESPECIALLY THE NAM
INDICATES SOME DECENT MID LEVEL FRONTOGENESIS...BETWEEN H85 AND
H7...ALONG/NORTH OF THE BOUNDARY AFTER MIDNIGHT WEDNESDAY NIGHT WITH
LIFT ALSO ENHANCED AS H7 SHORTWAVE TROUGH LIFTS ACROSS THE CENTRAL
PLAINS. WITH INCREASING LIFT OVERNIGHT WED NIGHT...ADDED IN SOME
LOW POPS.
ON THURSDAY...FRONT RESIDES ACROSS CENTRAL KANSAS TO OUR SOUTH WITH
SURFACE TROUGH/DRYLINE EXTENDING ALONG THE HIGH PLAINS. SREF
INDICATES MUCAPES OF 3000 J/KG ALONG/SOUTH OF THE BOUNDARY WITH 500
TO 1000 OR SO J/KG AHEAD OF DRY LINE ALONG HIGH PLAINS INTO SOUTHERN
NEBRASKA. EFFECTIVE SHEAR PARAMETERS ARE PROGGED BETWEEN 40 AND
50KTS. EASTERLY UPSLOPE FLOW...CONVERGENCE ALONG BOUNDARY AND NEXT
WAVE LIFTING OUT IS EXPECTED TO PROVIDE SUFFICIENT FORCING FOR
CONVECTIVE DEVELOPMENT AND A STRONG TO SEVERE STORM IS POSSIBLE.
OUR WESTERN CWA IS OUTLOOKED IN THE DAY3 FOR SEVERE WEATHER AND THIS
STILL LOOKS REASONABLE BASED ON LATEST MODEL RUNS WITH HAIL/WIND
LOOKING LIKE THE PRIMARY HAZARDS.
LIFT CONTINUES THURSDAY NIGHT AHEAD OF THE UPPER LOW PRESSURE SYSTEM
MOVING OUT OF THE SOUTH CENTRAL ROCKIES. THE ECMWF MAINTAINS A
SLOWER PROGRESSION OF THE SYSTEM THAN OTHER MODELS...AND THE SYSTEM
IS PROGGED TO LIFT ACROSS KANSAS INTO NEBRASKA ON FRIDAY. IT IS
SHAPING UP TO EVOLVE INTO A WIDESPREAD RAINFALL EVENT FROM THURSDAY
NIGHT AND LASTING POTENTIALLY INTO FRIDAY NIGHT WHEN THE SYSTEM
FILLS AND LIFTS TO THE NORTHEAST. INSTABILITY DIMINISHES SO NOT
LOOKING FOR A WHOLE LOT IN THE WAY OF THUNDER BUT SOME DECENT
RAINFALL AMOUNTS ARE POSSIBLE AS PRECIPITABLE WATER VALUES AVERAGE
AROUND AN INCH.
AS WAVE MOVES OFF EARLY IN THE WEEKEND...ANOTHER TROUGH/LOW NOSES
SOUTH ONTO THE PLAINS FM THE NC ROCKIES OVER THE WEEKEND PERIOD.
ALTHOUGH THE WEEKEND ITSELF DOES NOT LOOK LIKE A COMPLETE
RAINOUT...INTERMITTENT CHCS FOR RAINFALL DO EXIST. THE ECMWF
ADVERTISES A COLDER AIRMASS OVER THE WEEKEND COMPARED TO THE GFS
WITH H85 TEMPS DROPPING TO -3 OR -4C IN OUR NORTHERN ZONES...WHILE
THE GFS HAS TRENDED SLIGHTLY WARMER AROUND -2C. WILL KEEP PCPN AS
RAIN SHOWERS UNTIL THESE PERIODS GET CLOSER. CONFIDENCE IS NOT HIGH
REGARDING PCPN CHCS HEADING INTO NEXT WEEK BUT CANNOT ARGUE WITH
ENSEMBLE FORECAST ATTM. TROUGH AXIS LOOKS TO DEPART AROUND THE
TUESDAY TIME FRAME...WITH HEIGHT RISES/MODERATING TEMPS BEHIND THE
SYSTEM.
FOR TEMPS...AFTER HOT CONDITIONS WEDNESDAY...THURSDAY WILL BE COOLER
WITH A FAIRLY SHARP TEMP GRADIENT IN MAX TEMPS N/S...WARMING NEAR
THE FRONTAL ZONE. TEMPS WILL LIKELY STRUGGLE FRIDAY IN
CLOUDS/PCPN...THEN THE COLD AIRMASS SETTLES IN OVER THE WEEKEND.
50S LOOK TO HOLD SAT/SUN INTO MONDAY FOR HIGHS BEFORE AIRMASS MODERATES
TUESDAY. WILL NEED TO CONTINUE TO MONITOR LOW TEMPS FOR
FROST/FREEZE POTENTIAL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...BRYANT
SHORT TERM...SALTZMAN
LONG TERM...FAY
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
353 PM EDT MON APR 23 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CONTINUE TO PRODUCE UNSETTLED WEATHER
OVER THE NORTHEAST TODAY THROUGH MID-WEEK AS IT TRACKS NORTHWEST
TOWARD THE EASTERN GREAT LAKES. A SLOT OF DRIER AIR WILL MOVE INTO
THE NORTH COUNTRY...ALLOWING FOR SOME BREAKS IN PRECIPITATION TODAY AND
TONIGHT. THIS SYSTEM WILL MOVE OUT OF THE AREA WEDNESDAY...FOLLOWED
BY A BRIEF PERIOD OF HIGH PRESSURE WEDNESDAY NIGHT. MORE UNSETTLE
WEATHER WILL ARRIVE THURSDAY AS AN UPPER LEVEL TROUGH APPROACHES
THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 106 PM EDT MONDAY...UPDATED TO TWEAK TEMPS BASED ON CRNT OBS
AND DECREASE POPS TO SCHC/CHC ENTIRE CWA...AS WELL DEFINED DRY
SLOT MOVES ACRS OUR REGION. TEMPS WL RANGE FROM NEAR 40F MSS TO
U50S TO NEAR 60F NEAR RUTLAND TODAY. RUC13 HAS BEEN USED TO DEPICT
MAX TEMPS TODAY IN THE GRIDS. REST OF FCST IN GOOD SHAPE.
UPDATED TO REMOVE WIND ADVISORY SLV AND ADJUSTED PRECIP TIMING
BASED ON RADAR. WINDS ACRS THE SLV WL BE 15 TO 25 MPH WITH GUSTS
TO 35 MPH THRU THIS AFTN...BUT WL FALL SHORT OF ADVISORY CRITERIA.
OTHERWISE...AREAS OF LIGHT RAIN/DRIZZLE ESPECIALLY ACRS THE TRRN
WL CONT THRU THIS AFTN...BUT ADDITIONAL QPF WL BE UNDER 0.10".
TEMPS WL BE TRICKY AS STATED BEFORE WITH SOME CLRING DEVELOPING
ACRS THE SOUTHERN CPV AND TEMPS ALREADY AT 52F AT RUTLAND AND 60
AT KDDH. THIS WARMER AIR WL ADVECT NORTH INTO THE EASTERN
CPV/WESTERN SLOPES THIS AFTN. OTHERWISE...COOL NE FLW ACRS THE SLV
WL RESULT IN TEMPS ONLY IN THE U30S TO L40S. ALSO...SOME COOLER
TEMPS ANTICIPATED OVER THE SE UPSLOPE REGIONS OF THE GREENS.
INTERESTING EVENT LAST NIGHT WITH A DUSTING TO 4 INCHES OF SNOW
ACRS THE DACKS WITH SOME ICE ACCUMULATION ON POWERLINES AND TREES.
HAD SEVERAL REPORTS FROM POLICE AND MEDIA OF ISOLATED POWER
OUTAGES AND TREES DOWN DUE TO THE COMBINATION OF SNOW/ICE AND
GUSTY WINDS. SEE LATEST PNSBTV FOR FURTHER DETAILS.
QUICK UPDATE THIS MORNING TO FINE TUNE TIMING OF BACK EDGE OF
STEADIER/HEAVIER PRECIP ENDING ACRS OUR CENTRAL/NORTHERN CWA. CRNT
RADAR SHOWS STEADIER PRECIP ENDING ACRS CENTRAL VT INTO PARTS OF
THE DACKS...WHICH SHOULD CONT TO WORK NORTH TWD THE INTERNATIONAL
BORDER BY NOON. WL USE 100 POPS NORTH TO CHC POPS SOUTH THRU
NOON...THEN MENTION CHC POPS FOR THE REST OF THE DAY. TEMPS WL BE
TRICKY AND HIGHLY DEPEND UPON WINDS AND AMOUNT OF CLRING. VIS SATL
PIC SHOWS SOME BREAKS ACRS SOUTHERN VT ASSOCIATED WITH DRY SLOT
AND DEVELOPING DOWNSLOPE FLOW. THIS WL RESULT IN TEMPS WARMING
ALONG THE WESTERN SLOPES INTO THE 50S TO NEAR 60F...BUT COOL NE
FLW ACRS THE SLV WL KEEP THEM IN THE L/M40S. FOR THE CPV WL
MENTION HIGHS IN THE L/M50S AS WINDS SLOWLY SHIFT TO THE SE...WITH
MAINLY 40S FOR THE MTNS/CENTRAL VT.
HAVE CANCELLED THE WINTER WEATHER ADVISORY FOR THE NORTHERN
ADIRONDACKS AS DRY SLOT CONTINUES TO PROGRESS INTO NORTHERN NEW
YORK AND TEMPERATURES ARE SLOWLY WARMING FROM WARM AIR ADVECTION
ON THE NORTHEAST SIDE OF THE SFC LOW. FEW POCKETS OF RAIN/SNOW
MIX...AND POSSIBLY FREEZING RAIN MAY PERSIST...BUT LITTLE TO NO
ACCUMULATIONS EXPECTED AS TEMPERATURES WARM THIS MORNING.
DOWNSLOPING WINDS ON THE WESTERN SLOPES OF THE GREEN MOUNTAINS
HAS NOT COME TO FRUITION AS WINDS HAVE REMAINED 5 KTS OR LESS.
MODEL GUIDANCE SHOWS THAT THE 850MB JET HAS WEAKENED AND MOVED
NORTH...HAVE THEREFORE CANCELLED THE WIND ADVISORY FOR THAT AREA.
SUMMITS MAY STILL SEE STRONG GUSTS THIS MORNING INTO THE
AFTERNOON. ST. LAWRENCE VALLEY MAY STILL SEE SOME STRONG WIND
GUSTS AS 925MB JET HAS WEAKENED TO 30-45 KTS...BUT REMAINS OVER
THAT AREA THROUGH THE MORNING HOURS. HAVE KEPT THE WIND ADVISORY
OVER THE ST. LAWRENCE VALLEY FOR NOW.
OTHERWISE...PRECIPITATION MOVING INTO SOUTHERN VERMONT AND THE
CHAMPLAIN VALLEY MORE SHOWERY IN NATURE.
PREVIOUS DISCUSSION...ENHANCED CLOUD TOPS AND STRONG RADAR
REFLECTIVITIES OVER ADIRONDACKS IN NORTHERN NEW YORK WELL PROGGED
BY GFS FGEN. NAM SHOWING BEST FGEN MORE EAST...BUT BOTH MODELS
SHOW THIS FEATURE MOVING NORTH OUT OF THE AREA AS IT WEAKENS THIS
MORNING. WINTRY MIX AFFECTING THE NORTHERN ADIRONDACKS WITH
MAINLY SNOW OR RAIN AFFECTING THE ST LAWRENCE VALLEY.
TEMPERATURES GENERALLY WARMER AS YOU HEAD EAST...WITH RAIN
AFFECTING THE CHAMPLAIN VALLEY AND MOST OF VERMONT. TEMPS WILL
GRADUALLY WARM THIS MORNING WITH ANY WINTRY PRECIP CHANGING TO
ALL RAIN DURING THE DAY.
DRY SLOT SLOWLY ADVANCING NORTH FROM EASTERN NY THIS MORNING WILL
LEAD TO FEW BREAKS AND GENERALLY DECREASING POPS OVER THE NORTH
COUNTRY. AS SFC LOW SLOWS NEAR LAKE ONTARIO...NORTHERN NY LIKELY
TO SEE MORE PRECIP TODAY.
TYX RADAR WIND PROFILE SHOWING 40 KTS AT LOWEST LEVELS PERSISTING
EARLY THIS MORNING. LLJ OVER THE ST LAWRENCE VALLEY WEAKENING
DURING THE DAY WITH GUSTS IN THE MORNING OF 30-40 KTS DECREASING
TO LESS THAN 30 KTS THIS AFTERNOON. WIND NOT MIXING DOWN OFF THE
GREENS THIS MORNING WITH 850MB JET PROGGED TO WEAKEN QUICKLY
EARLY TODAY. LLJ ALSO LOOKS TO SHIFT MORE SOUTHERLY
TODAY...LIMITING DOWNSLOPING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AS OF 502 AM EDT MONDAY...POTENTIAL FOR GUSTY WINDS EXISTS THROUGH
TUESDAY...BUT LLJ MUCH WEAKER. SFC LOW WILL PIVOT LATE TONIGHT
INTO TUESDAY...BRINGING A SURGE OF PRECIP OVER NORTHERN NY. THIS
WILL ALSO BRING IN COOLER TEMPERATURES...ESPECIALLY ALOFT...WITH
NEGATIVE SINGLE DIGIT TEMPS AT 850MB AND 925MB OVER NORTHERN NY
AND EDGING INTO VERMONT TONIGHT. WITH THESE COOLER TEMPS...CAN
EXPECT GREATER CHANCE FOR ANY PRECIP OVERNIGHT TO BE RAIN/SNOW MIX
TO ALL SNOW OVER THE ADIRONDACKS. SNOWFALL AMOUNTS OVERNIGHT WILL
RANGE FROM A DUSTING TO LESS THAN ONE INCH. THE COOLER AIR ALOFT
WILL LEAD TO COOLER MAX TEMPS ON TUESDAY...WITH HIGHS IN THE 40S
TO LOW 50S.
THE FAIRLY STACKED LOW WILL GAIN MOMENTUM NORTHWARD LATE TUESDAY
AND TUESDAY NIGHT WITH DECREASING CHANCES FOR PRECIP AS THE
DAY/NIGHT GO ON. THERES STILL A CHANCE FOR SNOW SHOWERS TUESDAY
NIGHT MAINLY OVER THE HIGHER TERRAIN WITH LESS THAN ONE INCH
ACCUMULATION EXPECTED AT THIS TIME.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 340 PM EDT MONDAY...COOL AND MOSTLY WET PATTERN ON TAP FOR
THE EXTENDED PERIOD. THIS WILL BE SET UP BY BROAD UPPER LOW
PRESSURE SYSTEM THAT WILL REMAIN OVER EASTERN CANADA. FIRST SYSTEM
WILL PIVOT AROUND UPPER LOW THURSDAY AS IS PUSHES THRU THE GREAT
LKS REGION...THEN THRU THE REGION BY FRIDAY. NNW FLOW BEHIND THIS
EXITING SYSTEM WILL KEEP CHANCE FOR LGT PRECIP OVER NORTHERN ZONES
THRU FRIDAY...BFR WK RIDGE BUILDS OVER AREA FOR SATURDAY. ANOTHER
LOW COMING ACROSS THE CENTRAL PLAINS LATE SATURDAY WILL GET CAUGHT
IN THE UPPER LOW CIRCULATION. MDLS DO DIFFER AS TO EXTENT OF
PRECIP COMING INTO CWA...WITH ECMWF SWINGING THIS SYSTEM JUST
SOUTH OF THE REGION...WHILE THE GFS SWINGS PRECIP THRU...AIDED BY
DEVELOPMENT OF MIDLEVEL CUTOFF LEVEL. WILL SPLIT DIFFERENCE OF
THESE TWO W/ BULK OF PRECIP STAYING SOUTH. HIGHEST POPS OVER
SOUTHERN ZONES. W/ CWA UNDER BROAD NW FLOW DURING THIS TIME...NOT
EXPECTING MAJOR SWINGS IN TEMPS DURING THE DAYTIME HRS...AND WILL
KEEP CLOSE TO MDL GUIDANCE IN THE 50S W/ SOME 40S IN THE HILLS OF
DACKS/NE VT. FOR OVERNGT LOWS...CD AIR INTRUSION WILL ALLOW FOR
MIX WITH/CHANGE TO -SW ESPECIALLY OVER HIR TRRN...W/ LITTLE ACCUM.
GOING FOR 30S IN VALLEYS AND 20S IN THE DACKS/GREEN MTNS.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...LOW PRESSURE SYSTEM MVG WNW THRU NY ATTM
WILL ALLOW FOR BREAKS IN CLD COVER THRU 00Z TUESDAY. LOOKING FOR
MAINLY A MIX OF MVFR TO LIFR SKY COND DURING THIS TIME WITH
CEILINGS DIPPING DOWN TO BLW OVC010. GRADUAL INCR OF CEILINGS
OVERNGT THRU 18Z TUESDAY AS WINDS SHIFT WITH LOW OVER SOUTHERN
ONTARIO. MAINLY IFR/MVFR CEILINGS WITH SOME VFR AFT 13Z TUESDAY.
PRECIP POSSIBLE DUE TO LOW CEILINGS. BEST CHANCES IN MSS/SLK WHERE
RW/SW POSSIBLE. SOME FG FORMATION OVERNGT HAMPERED OVERALL BY
STRONG WINDS SHIFTING FROM MAINLY NNE TO SSW 10-20KTS...WITH GUSTS
TO 25KTS AFT 14Z.
OUTLOOK 18Z TUESDAY THROUGH SATURDAY...
18Z TUESDAY THROUGH 00Z THURSDAY...VFR WITH PERIODS OF MVFR/IFR IN
SCATTERED RAIN/SNOW SHOWERS WITH UPPER LEVEL LOW...ESPECIALLY AT
SLK/MPV.
00Z THURSDAY THROUGH 12Z THURSDAY...PRIMARILY VFR BETWEEN
STORM SYSTEMS.
12Z THURSDAY THROUGH SATURDAY...VFR WITH PERIODS OF MVFR/IFR IN
RAIN/SNOW SHOWERS WITH FRONTAL SYSTEM...ESPECIALLY SLK/MPV.
&&
.MARINE...
AS OF 350 PM EDT MONDAY...A LAKE WIND ADVISORY WILL GO INTO EFFECT
AFTER MIDNIGHT TONIGHT. NORTH WINDS THIS AFTERNOON AND EVENING
FROM 5 TO 15 KNOTS WILL TURN SOUTHERLY OVERNIGHT AND INCREASE TO
15 TO 25 KNOTS LATE TONIGHT. THE ADVISORY WILL LIKELY NEED TO BE
CONTINUED THROUGH TUESDAY AS WINDS ARE EXPECTED TO INCREASE
FURTHER TO 20 TO 30 KNOTS. WAVES OF 1 TO 3 FEET TONIGHT WILL
BUILD TO 2 TO 4 FEET ON TUESDAY.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KM
NEAR TERM...KM/TABER
SHORT TERM...KM
LONG TERM...JN
AVIATION...JN/SLW
MARINE...WFO BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
340 PM EDT MON APR 23 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CONTINUE TO PRODUCE UNSETTLED WEATHER
OVER THE NORTHEAST TODAY THROUGH MID-WEEK AS IT TRACKS NORTHWEST
TOWARD THE EASTERN GREAT LAKES. A SLOT OF DRIER AIR WILL MOVE INTO
THE NORTH COUNTRY...ALLOWING FOR SOME BREAKS IN PRECIPITATION TODAY AND
TONIGHT. THIS SYSTEM WILL MOVE OUT OF THE AREA WEDNESDAY...FOLLOWED
BY A BRIEF PERIOD OF HIGH PRESSURE WEDNESDAY NIGHT. MORE UNSETTLE
WEATHER WILL ARRIVE THURSDAY AS AN UPPER LEVEL TROUGH APPROACHES
THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 106 PM EDT MONDAY...UPDATED TO TWEAK TEMPS BASED ON CRNT OBS
AND DECREASE POPS TO SCHC/CHC ENTIRE CWA...AS WELL DEFINED DRY
SLOT MOVES ACRS OUR REGION. TEMPS WL RANGE FROM NEAR 40F MSS TO
U50S TO NEAR 60F NEAR RUTLAND TODAY. RUC13 HAS BEEN USED TO DEPICT
MAX TEMPS TODAY IN THE GRIDS. REST OF FCST IN GOOD SHAPE.
UPDATED TO REMOVE WIND ADVISORY SLV AND ADJUSTED PRECIP TIMING
BASED ON RADAR. WINDS ACRS THE SLV WL BE 15 TO 25 MPH WITH GUSTS
TO 35 MPH THRU THIS AFTN...BUT WL FALL SHORT OF ADVISORY CRITERIA.
OTHERWISE...AREAS OF LIGHT RAIN/DRIZZLE ESPECIALLY ACRS THE TRRN
WL CONT THRU THIS AFTN...BUT ADDITIONAL QPF WL BE UNDER 0.10".
TEMPS WL BE TRICKY AS STATED BEFORE WITH SOME CLRING DEVELOPING
ACRS THE SOUTHERN CPV AND TEMPS ALREADY AT 52F AT RUTLAND AND 60
AT KDDH. THIS WARMER AIR WL ADVECT NORTH INTO THE EASTERN
CPV/WESTERN SLOPES THIS AFTN. OTHERWISE...COOL NE FLW ACRS THE SLV
WL RESULT IN TEMPS ONLY IN THE U30S TO L40S. ALSO...SOME COOLER
TEMPS ANTICIPATED OVER THE SE UPSLOPE REGIONS OF THE GREENS.
INTERESTING EVENT LAST NIGHT WITH A DUSTING TO 4 INCHES OF SNOW
ACRS THE DACKS WITH SOME ICE ACCUMULATION ON POWERLINES AND TREES.
HAD SEVERAL REPORTS FROM POLICE AND MEDIA OF ISOLATED POWER
OUTAGES AND TREES DOWN DUE TO THE COMBINATION OF SNOW/ICE AND
GUSTY WINDS. SEE LATEST PNSBTV FOR FURTHER DETAILS.
QUICK UPDATE THIS MORNING TO FINE TUNE TIMING OF BACK EDGE OF
STEADIER/HEAVIER PRECIP ENDING ACRS OUR CENTRAL/NORTHERN CWA. CRNT
RADAR SHOWS STEADIER PRECIP ENDING ACRS CENTRAL VT INTO PARTS OF
THE DACKS...WHICH SHOULD CONT TO WORK NORTH TWD THE INTERNATIONAL
BORDER BY NOON. WL USE 100 POPS NORTH TO CHC POPS SOUTH THRU
NOON...THEN MENTION CHC POPS FOR THE REST OF THE DAY. TEMPS WL BE
TRICKY AND HIGHLY DEPEND UPON WINDS AND AMOUNT OF CLRING. VIS SATL
PIC SHOWS SOME BREAKS ACRS SOUTHERN VT ASSOCIATED WITH DRY SLOT
AND DEVELOPING DOWNSLOPE FLOW. THIS WL RESULT IN TEMPS WARMING
ALONG THE WESTERN SLOPES INTO THE 50S TO NEAR 60F...BUT COOL NE
FLW ACRS THE SLV WL KEEP THEM IN THE L/M40S. FOR THE CPV WL
MENTION HIGHS IN THE L/M50S AS WINDS SLOWLY SHIFT TO THE SE...WITH
MAINLY 40S FOR THE MTNS/CENTRAL VT.
HAVE CANCELLED THE WINTER WEATHER ADVISORY FOR THE NORTHERN
ADIRONDACKS AS DRY SLOT CONTINUES TO PROGRESS INTO NORTHERN NEW
YORK AND TEMPERATURES ARE SLOWLY WARMING FROM WARM AIR ADVECTION
ON THE NORTHEAST SIDE OF THE SFC LOW. FEW POCKETS OF RAIN/SNOW
MIX...AND POSSIBLY FREEZING RAIN MAY PERSIST...BUT LITTLE TO NO
ACCUMULATIONS EXPECTED AS TEMPERATURES WARM THIS MORNING.
DOWNSLOPING WINDS ON THE WESTERN SLOPES OF THE GREEN MOUNTAINS
HAS NOT COME TO FRUITION AS WINDS HAVE REMAINED 5 KTS OR LESS.
MODEL GUIDANCE SHOWS THAT THE 850MB JET HAS WEAKENED AND MOVED
NORTH...HAVE THEREFORE CANCELLED THE WIND ADVISORY FOR THAT AREA.
SUMMITS MAY STILL SEE STRONG GUSTS THIS MORNING INTO THE
AFTERNOON. ST. LAWRENCE VALLEY MAY STILL SEE SOME STRONG WIND
GUSTS AS 925MB JET HAS WEAKENED TO 30-45 KTS...BUT REMAINS OVER
THAT AREA THROUGH THE MORNING HOURS. HAVE KEPT THE WIND ADVISORY
OVER THE ST. LAWRENCE VALLEY FOR NOW.
OTHERWISE...PRECIPITATION MOVING INTO SOUTHERN VERMONT AND THE
CHAMPLAIN VALLEY MORE SHOWERY IN NATURE.
PREVIOUS DISCUSSION...ENHANCED CLOUD TOPS AND STRONG RADAR
REFLECTIVITIES OVER ADIRONDACKS IN NORTHERN NEW YORK WELL PROGGED
BY GFS FGEN. NAM SHOWING BEST FGEN MORE EAST...BUT BOTH MODELS
SHOW THIS FEATURE MOVING NORTH OUT OF THE AREA AS IT WEAKENS THIS
MORNING. WINTRY MIX AFFECTING THE NORTHERN ADIRONDACKS WITH
MAINLY SNOW OR RAIN AFFECTING THE ST LAWRENCE VALLEY.
TEMPERATURES GENERALLY WARMER AS YOU HEAD EAST...WITH RAIN
AFFECTING THE CHAMPLAIN VALLEY AND MOST OF VERMONT. TEMPS WILL
GRADUALLY WARM THIS MORNING WITH ANY WINTRY PRECIP CHANGING TO
ALL RAIN DURING THE DAY.
DRY SLOT SLOWLY ADVANCING NORTH FROM EASTERN NY THIS MORNING WILL
LEAD TO FEW BREAKS AND GENERALLY DECREASING POPS OVER THE NORTH
COUNTRY. AS SFC LOW SLOWS NEAR LAKE ONTARIO...NORTHERN NY LIKELY
TO SEE MORE PRECIP TODAY.
TYX RADAR WIND PROFILE SHOWING 40 KTS AT LOWEST LEVELS PERSISTING
EARLY THIS MORNING. LLJ OVER THE ST LAWRENCE VALLEY WEAKENING
DURING THE DAY WITH GUSTS IN THE MORNING OF 30-40 KTS DECREASING
TO LESS THAN 30 KTS THIS AFTERNOON. WIND NOT MIXING DOWN OFF THE
GREENS THIS MORNING WITH 850MB JET PROGGED TO WEAKEN QUICKLY
EARLY TODAY. LLJ ALSO LOOKS TO SHIFT MORE SOUTHERLY
TODAY...LIMITING DOWNSLOPING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AS OF 502 AM EDT MONDAY...POTENTIAL FOR GUSTY WINDS EXISTS THROUGH
TUESDAY...BUT LLJ MUCH WEAKER. SFC LOW WILL PIVOT LATE TONIGHT
INTO TUESDAY...BRINGING A SURGE OF PRECIP OVER NORTHERN NY. THIS
WILL ALSO BRING IN COOLER TEMPERATURES...ESPECIALLY ALOFT...WITH
NEGATIVE SINGLE DIGIT TEMPS AT 850MB AND 925MB OVER NORTHERN NY
AND EDGING INTO VERMONT TONIGHT. WITH THESE COOLER TEMPS...CAN
EXPECT GREATER CHANCE FOR ANY PRECIP OVERNIGHT TO BE RAIN/SNOW MIX
TO ALL SNOW OVER THE ADIRONDACKS. SNOWFALL AMOUNTS OVERNIGHT WILL
RANGE FROM A DUSTING TO LESS THAN ONE INCH. THE COOLER AIR ALOFT
WILL LEAD TO COOLER MAX TEMPS ON TUESDAY...WITH HIGHS IN THE 40S
TO LOW 50S.
THE FAIRLY STACKED LOW WILL GAIN MOMENTUM NORTHWARD LATE TUESDAY
AND TUESDAY NIGHT WITH DECREASING CHANCES FOR PRECIP AS THE
DAY/NIGHT GO ON. THERES STILL A CHANCE FOR SNOW SHOWERS TUESDAY
NIGHT MAINLY OVER THE HIGHER TERRAIN WITH LESS THAN ONE INCH
ACCUMULATION EXPECTED AT THIS TIME.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 340 PM EDT MONDAY...COOL AND MOSTLY WET PATTERN ON TAP FOR
THE EXTENDED PERIOD. THIS WILL BE SET UP BY BROAD UPPER LOW
PRESSURE SYSTEM THAT WILL REMAIN OVER EASTERN CANADA. FIRST SYSTEM
WILL PIVOT AROUND UPPER LOW THURSDAY AS IS PUSHES THRU THE GREAT
LKS REGION...THEN THRU THE REGION BY FRIDAY. NNW FLOW BEHIND THIS
EXITING SYSTEM WILL KEEP CHANCE FOR LGT PRECIP OVER NORTHERN ZONES
THRU FRIDAY...BFR WK RIDGE BUILDS OVER AREA FOR SATURDAY. ANOTHER
LOW COMING ACROSS THE CENTRAL PLAINS LATE SATURDAY WILL GET CAUGHT
IN THE UPPER LOW CIRCULATION. MDLS DO DIFFER AS TO EXTENT OF
PRECIP COMING INTO CWA...WITH ECMWF SWINGING THIS SYSTEM JUST
SOUTH OF THE REGION...WHILE THE GFS SWINGS PRECIP THRU...AIDED BY
DEVELOPMENT OF MIDLEVEL CUTOFF LEVEL. WILL SPLIT DIFFERENCE OF
THESE TWO W/ BULK OF PRECIP STAYING SOUTH. HIGHEST POPS OVER
SOUTHERN ZONES. W/ CWA UNDER BROAD NW FLOW DURING THIS TIME...NOT
EXPECTING MAJOR SWINGS IN TEMPS DURING THE DAYTIME HRS...AND WILL
KEEP CLOSE TO MDL GUIDANCE IN THE 50S W/ SOME 40S IN THE HILLS OF
DACKS/NE VT. FOR OVERNGT LOWS...CD AIR INTRUSION WILL ALLOW FOR
MIX WITH/CHANGE TO -SW ESPECIALLY OVER HIR TRRN...W/ LITTLE ACCUM.
GOING FOR 30S IN VALLEYS AND 20S IN THE DACKS/GREEN MTNS.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...LOW PRESSURE SYSTEM MVG WNW THRU NY ATTM
WILL ALLOW FOR BREAKS IN CLD COVER THRU 00Z TUESDAY. LOOKING FOR
MAINLY A MIX OF MVFR TO LIFR SKY COND DURING THIS TIME WITH
CEILINGS DIPPING DOWN TO BLW OVC010. GRADUAL INCR OF CEILINGS
OVERNGT THRU 18Z TUESDAY AS WINDS SHIFT WITH LOW OVER SOUTHERN
ONTARIO. MAINLY IFR/MVFR CEILINGS WITH SOME VFR AFT 13Z TUESDAY.
PRECIP POSSIBLE DUE TO LOW CEILINGS. BEST CHANCES IN MSS/SLK WHERE
RW/SW POSSIBLE. SOME FG FORMATION OVERNGT HAMPERED OVERALL BY
STRONG WINDS SHIFTING FROM MAINLY NNE TO SSW 10-20KTS...WITH GUSTS
TO 25KTS AFT 14Z.
OUTLOOK 18Z TUESDAY THROUGH SATURDAY...
18Z TUESDAY THROUGH 00Z THURSDAY...VFR WITH PERIODS OF MVFR/IFR IN
SCATTERED RAIN/SNOW SHOWERS WITH UPPER LEVEL LOW...ESPECIALLY AT
SLK/MPV.
00Z THURSDAY THROUGH 12Z THURSDAY...PRIMARILY VFR BETWEEN
STORM SYSTEMS.
12Z THURSDAY THROUGH SATURDAY...VFR WITH PERIODS OF MVFR/IFR IN
RAIN/SNOW SHOWERS WITH FRONTAL SYSTEM...ESPECIALLY SLK/MPV.
&&
.MARINE...
AS OF 445 AM EDT MONDAY...LAKE WIND ADVISORY IS IN EFFECT FOR
TODAY...ESPECIALLY THE MORNING.
NORTH WINDS OF 15 TO 25 WILL CONTINUE THROUGH MID-MORNING BEFORE
DECREASING TO 10 KNOTS THIS AFTERNOON.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KM
NEAR TERM...KM/TABER
SHORT TERM...KM
LONG TERM...JN
AVIATION...JN/SLW
MARINE...
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
136 PM EDT MON APR 23 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CONTINUE TO PRODUCE UNSETTLED WEATHER
OVER THE NORTHEAST TODAY THROUGH MID-WEEK AS IT TRACKS NORTHWEST
TOWARD THE EASTERN GREAT LAKES. A SLOT OF DRIER AIR WILL MOVE INTO
THE NORTH COUNTRY...ALLOWING FOR SOME BREAKS IN PRECIPITATION TODAY AND
TONIGHT. THIS SYSTEM WILL MOVE OUT OF THE AREA WEDNESDAY...FOLLOWED
BY A BRIEF PERIOD OF HIGH PRESSURE WEDNESDAY NIGHT. MORE UNSETTLE
WEATHER WILL ARRIVE THURSDAY AS AN UPPER LEVEL TROUGH APPROACHES
THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 106 PM EDT MONDAY...UPDATED TO TWEAK TEMPS BASED ON CRNT OBS
AND DECREASE POPS TO SCHC/CHC ENTIRE CWA...AS WELL DEFINED DRY
SLOT MOVES ACRS OUR REGION. TEMPS WL RANGE FROM NEAR 40F MSS TO
U50S TO NEAR 60F NEAR RUTLAND TODAY. RUC13 HAS BEEN USED TO DEPICT
MAX TEMPS TODAY IN THE GRIDS. REST OF FCST IN GOOD SHAPE.
UPDATED TO REMOVE WIND ADVISORY SLV AND ADJUSTED PRECIP TIMING
BASED ON RADAR. WINDS ACRS THE SLV WL BE 15 TO 25 MPH WITH GUSTS
TO 35 MPH THRU THIS AFTN...BUT WL FALL SHORT OF ADVISORY CRITERIA.
OTHERWISE...AREAS OF LIGHT RAIN/DRIZZLE ESPECIALLY ACRS THE TRRN
WL CONT THRU THIS AFTN...BUT ADDITIONAL QPF WL BE UNDER 0.10".
TEMPS WL BE TRICKY AS STATED BEFORE WITH SOME CLRING DEVELOPING
ACRS THE SOUTHERN CPV AND TEMPS ALREADY AT 52F AT RUTLAND AND 60
AT KDDH. THIS WARMER AIR WL ADVECT NORTH INTO THE EASTERN
CPV/WESTERN SLOPES THIS AFTN. OTHERWISE...COOL NE FLW ACRS THE SLV
WL RESULT IN TEMPS ONLY IN THE U30S TO L40S. ALSO...SOME COOLER
TEMPS ANTICIPATED OVER THE SE UPSLOPE REGIONS OF THE GREENS.
INTERESTING EVENT LAST NIGHT WITH A DUSTING TO 4 INCHES OF SNOW
ACRS THE DACKS WITH SOME ICE ACCUMULATION ON POWERLINES AND TREES.
HAD SEVERAL REPORTS FROM POLICE AND MEDIA OF ISOLATED POWER
OUTAGES AND TREES DOWN DUE TO THE COMBINATION OF SNOW/ICE AND
GUSTY WINDS. SEE LATEST PNSBTV FOR FURTHER DETAILS.
QUICK UPDATE THIS MORNING TO FINE TUNE TIMING OF BACK EDGE OF
STEADIER/HEAVIER PRECIP ENDING ACRS OUR CENTRAL/NORTHERN CWA. CRNT
RADAR SHOWS STEADIER PRECIP ENDING ACRS CENTRAL VT INTO PARTS OF
THE DACKS...WHICH SHOULD CONT TO WORK NORTH TWD THE INTERNATIONAL
BORDER BY NOON. WL USE 100 POPS NORTH TO CHC POPS SOUTH THRU
NOON...THEN MENTION CHC POPS FOR THE REST OF THE DAY. TEMPS WL BE
TRICKY AND HIGHLY DEPEND UPON WINDS AND AMOUNT OF CLRING. VIS SATL
PIC SHOWS SOME BREAKS ACRS SOUTHERN VT ASSOCIATED WITH DRY SLOT
AND DEVELOPING DOWNSLOPE FLOW. THIS WL RESULT IN TEMPS WARMING
ALONG THE WESTERN SLOPES INTO THE 50S TO NEAR 60F...BUT COOL NE
FLW ACRS THE SLV WL KEEP THEM IN THE L/M40S. FOR THE CPV WL
MENTION HIGHS IN THE L/M50S AS WINDS SLOWLY SHIFT TO THE SE...WITH
MAINLY 40S FOR THE MTNS/CENTRAL VT.
HAVE CANCELLED THE WINTER WEATHER ADVISORY FOR THE NORTHERN
ADIRONDACKS AS DRY SLOT CONTINUES TO PROGRESS INTO NORTHERN NEW
YORK AND TEMPERATURES ARE SLOWLY WARMING FROM WARM AIR ADVECTION
ON THE NORTHEAST SIDE OF THE SFC LOW. FEW POCKETS OF RAIN/SNOW
MIX...AND POSSIBLY FREEZING RAIN MAY PERSIST...BUT LITTLE TO NO
ACCUMULATIONS EXPECTED AS TEMPERATURES WARM THIS MORNING.
DOWNSLOPING WINDS ON THE WESTERN SLOPES OF THE GREEN MOUNTAINS
HAS NOT COME TO FRUITION AS WINDS HAVE REMAINED 5 KTS OR LESS.
MODEL GUIDANCE SHOWS THAT THE 850MB JET HAS WEAKENED AND MOVED
NORTH...HAVE THEREFORE CANCELLED THE WIND ADVISORY FOR THAT AREA.
SUMMITS MAY STILL SEE STRONG GUSTS THIS MORNING INTO THE
AFTERNOON. ST. LAWRENCE VALLEY MAY STILL SEE SOME STRONG WIND
GUSTS AS 925MB JET HAS WEAKENED TO 30-45 KTS...BUT REMAINS OVER
THAT AREA THROUGH THE MORNING HOURS. HAVE KEPT THE WIND ADVISORY
OVER THE ST. LAWRENCE VALLEY FOR NOW.
OTHERWISE...PRECIPITATION MOVING INTO SOUTHERN VERMONT AND THE
CHAMPLAIN VALLEY MORE SHOWERY IN NATURE.
PREVIOUS DISCUSSION...ENHANCED CLOUD TOPS AND STRONG RADAR
REFLECTIVITIES OVER ADIRONDACKS IN NORTHERN NEW YORK WELL PROGGED
BY GFS FGEN. NAM SHOWING BEST FGEN MORE EAST...BUT BOTH MODELS
SHOW THIS FEATURE MOVING NORTH OUT OF THE AREA AS IT WEAKENS THIS
MORNING. WINTRY MIX AFFECTING THE NORTHERN ADIRONDACKS WITH
MAINLY SNOW OR RAIN AFFECTING THE ST LAWRENCE VALLEY.
TEMPERATURES GENERALLY WARMER AS YOU HEAD EAST...WITH RAIN
AFFECTING THE CHAMPLAIN VALLEY AND MOST OF VERMONT. TEMPS WILL
GRADUALLY WARM THIS MORNING WITH ANY WINTRY PRECIP CHANGING TO
ALL RAIN DURING THE DAY.
DRY SLOT SLOWLY ADVANCING NORTH FROM EASTERN NY THIS MORNING WILL
LEAD TO FEW BREAKS AND GENERALLY DECREASING POPS OVER THE NORTH
COUNTRY. AS SFC LOW SLOWS NEAR LAKE ONTARIO...NORTHERN NY LIKELY
TO SEE MORE PRECIP TODAY.
TYX RADAR WIND PROFILE SHOWING 40 KTS AT LOWEST LEVELS PERSISTING
EARLY THIS MORNING. LLJ OVER THE ST LAWRENCE VALLEY WEAKENING
DURING THE DAY WITH GUSTS IN THE MORNING OF 30-40 KTS DECREASING
TO LESS THAN 30 KTS THIS AFTERNOON. WIND NOT MIXING DOWN OFF THE
GREENS THIS MORNING WITH 850MB JET PROGGED TO WEAKEN QUICKLY
EARLY TODAY. LLJ ALSO LOOKS TO SHIFT MORE SOUTHERLY
TODAY...LIMITING DOWNSLOPING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
AS OF 502 AM EDT MONDAY...POTENTIAL FOR GUSTY WINDS EXISTS THROUGH
TUESDAY...BUT LLJ MUCH WEAKER. SFC LOW WILL PIVOT LATE TONIGHT
INTO TUESDAY...BRINGING A SURGE OF PRECIP OVER NORTHERN NY. THIS
WILL ALSO BRING IN COOLER TEMPERATURES...ESPECIALLY ALOFT...WITH
NEGATIVE SINGLE DIGIT TEMPS AT 850MB AND 925MB OVER NORTHERN NY
AND EDGING INTO VERMONT TONIGHT. WITH THESE COOLER TEMPS...CAN
EXPECT GREATER CHANCE FOR ANY PRECIP OVERNIGHT TO BE RAIN/SNOW MIX
TO ALL SNOW OVER THE ADIRONDACKS. SNOWFALL AMOUNTS OVERNIGHT WILL
RANGE FROM A DUSTING TO LESS THAN ONE INCH. THE COOLER AIR ALOFT
WILL LEAD TO COOLER MAX TEMPS ON TUESDAY...WITH HIGHS IN THE 40S
TO LOW 50S.
THE FAIRLY STACKED LOW WILL GAIN MOMENTUM NORTHWARD LATE TUESDAY
AND TUESDAY NIGHT WITH DECREASING CHANCES FOR PRECIP AS THE
DAY/NIGHT GO ON. THERES STILL A CHANCE FOR SNOW SHOWERS TUESDAY
NIGHT MAINLY OVER THE HIGHER TERRAIN WITH LESS THAN ONE INCH
ACCUMULATION EXPECTED AT THIS TIME.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 434 AM EDT MONDAY...SIMILAR TO THINKING SUNDAY AT THIS
TIME...MONDAY/S CLOSED SYSTEM WEAKENING AND BECOMING ABSORBED BY
CLOSED LOW IN JAMES BAY BUT WILL EVENTUALLY RETURN IN A DIFFERENT
FASHION LATER THIS WEEK AND EARLY NEXT WEEKEND. WINTER IN LATE
APRIL AFTER SUMMER IN MID-MARCH...GO FIGURE?!
AGAIN...TROFINESS HANGS ON WED WITH LESSENING CHC OF -SHRA EACH
MOMENT. OVERALL FLOW PATTERN STILL NW AND CYCLONIC BACKING
TOWARD W AND SW AHEAD OF NEXT STG S/W ROTATING ARD HUDSON BAY CLOSED
LOW WHICH WILL BRING A SERIES OF COLD FRONTS AND -SHRA THREAT ON
THU/THU NGT AND PSBLY FRI. THERE/S BEEN A ONGOING CHANGE HERE...
ALL MODELS ARE COMING INTO PHASE OF A STG NRN STREAM S/W ROTATING
INTO FA WITH SFC LOW DEVELOPMENT THU AFTN-FRI WHICH WILL BRING MORE
OF A STEADY PCPN VS SHOWERY WITH PERHAPS SOME SNOW AS WELL.
THEREAFTER...COLD NNW FLOW AND SFC HIGH DIRECTLY FM POLAR REGIONS
MOVES INTO FA FOR SAT/SUN. MIN/MAX TEMPS FOR FRI/SAT ARE FCST 10+
DEGS BLO NORMAL (DAYS 6/7) WHICH MEANS CUD BE COLDER.
THERE ARE STILL QUESTIONS FOR SUNDAY AS A LEFTOVER BOUNDARY FM
THU/FRI SYSTEM LIES JUST S OF SNE WITH ANOTHER NRN STREAM S/W
ROTATING SE TOWARD GRT LAKES AND POSSIBLE SFC LOW DVLPMNT ALG THIS
BOUNDARY WITH A THREAT OF RAIN ACRS SRN FA.
FROST/FREEZE PROGRAM BEGINS IN CHAMPL VLY/ST LWRNC VLY APRIL
25TH...APPROX 10 DAYS EARLY DUE TO ABNORMALLY WARM WINTER/SPRING AND
HORTICULUTURE SEASON RUNNING WEEKS EARLY.
BEGINNING/ENDING FROST/FREEZE PROGRAM IS ALWAYS PROBLEMATIC DUE TO
DIFFERENT CLIMATE REGIONS ACROSS CWA. IT WILL ACTUALLY BE COLDER IN
INTERIOR VERMONT AND NORTHERN NY YET DUE TO THE START OF THE PROGRAM
BEING MAY 5TH AND MAY 15TH THERE WUD BE NO HEADLINES.
HEADLINES OR NOT...IF TEMPERATURES GET INTO THE 20S/L30S PROTECTION
OF ANY CROPS/PLANTS NEED TO BE TAKEN. APPLE ORCHARDS AND WINE
VINEYARDS ARE AT A SUSCEPTIBLE POINT WITH TEMPS IN THE M20S POSSIBLY
CAUSING DEVASTATING EFFECTS.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...LOW PRESSURE SYSTEM MVG WNW THRU NY ATTM
WILL ALLOW FOR BREAKS IN CLD COVER THRU 00Z TUESDAY. LOOKING FOR
MAINLY A MIX OF MVFR TO LIFR SKY COND DURING THIS TIME WITH
CEILINGS DIPPING DOWN TO BLW OVC010. GRADUAL INCR OF CEILINGS
OVERNGT THRU 18Z TUESDAY AS WINDS SHIFT WITH LOW OVER SOUTHERN
ONTARIO. MAINLY IFR/MVFR CEILINGS WITH SOME VFR AFT 13Z TUESDAY.
PRECIP POSSIBLE DUE TO LOW CEILINGS. BEST CHANCES IN MSS/SLK WHERE
RW/SW POSSIBLE. SOME FG FORMATION OVERNGT HAMPERED OVERALL BY
STRONG WINDS SHIFTING FROM MAINLY NNE TO SSW 10-20KTS...WITH GUSTS
TO 25KTS AFT 14Z.
OUTLOOK 18Z TUESDAY THROUGH SATURDAY...
18Z TUESDAY THROUGH 00Z THURSDAY...VFR WITH PERIODS OF MVFR/IFR IN
SCATTERED RAIN/SNOW SHOWERS WITH UPPER LEVEL LOW...ESPECIALLY AT
SLK/MPV.
00Z THURSDAY THROUGH 12Z THURSDAY...PRIMARILY VFR BETWEEN
STORM SYSTEMS.
12Z THURSDAY THROUGH SATURDAY...VFR WITH PERIODS OF MVFR/IFR IN
RAIN/SNOW SHOWERS WITH FRONTAL SYSTEM...ESPECIALLY SLK/MPV.
&&
.MARINE...
AS OF 445 AM EDT MONDAY...LAKE WIND ADVISORY IS IN EFFECT FOR
TODAY...ESPECIALLY THE MORNING.
NORTH WINDS OF 15 TO 25 WILL CONTINUE THROUGH MID-MORNING BEFORE
DECREASING TO 10 KNOTS THIS AFTERNOON.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KM
NEAR TERM...KM/TABER
SHORT TERM...KM
LONG TERM...SLW
AVIATION...JN/SLW
MARINE...NWS BTV
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
109 PM EDT MON APR 23 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL CONTINUE TO PRODUCE UNSETTLED WEATHER
OVER THE NORTHEAST TODAY THROUGH MID-WEEK AS IT TRACKS NORTHWEST
TOWARD THE EASTERN GREAT LAKES. A SLOT OF DRIER AIR WILL MOVE INTO
THE NORTH COUNTRY...ALLOWING FOR SOME BREAKS IN PRECIPITATION TODAY AND
TONIGHT. THIS SYSTEM WILL MOVE OUT OF THE AREA WEDNESDAY...FOLLOWED
BY A BRIEF PERIOD OF HIGH PRESSURE WEDNESDAY NIGHT. MORE UNSETTLE
WEATHER WILL ARRIVE THURSDAY AS AN UPPER LEVEL TROUGH APPROACHES
THE REGION.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 106 PM EDT MONDAY...UPDATED TO TWEAK TEMPS BASED ON CRNT OBS
AND DECREASE POPS TO SCHC/CHC ENTIRE CWA...AS WELL DEFINED DRY
SLOT MOVES ACRS OUR REGION. TEMPS WL RANGE FROM NEAR 40F MSS TO
U50S TO NEAR 60F NEAR RUTLAND TODAY. RUC13 HAS BEEN USED TO DEPICT
MAX TEMPS TODAY IN THE GRIDS. REST OF FCST IN GOOD SHAPE.
UPDATED TO REMOVE WIND ADVISORY SLV AND ADJUSTED PRECIP TIMING
BASED ON RADAR. WINDS ACRS THE SLV WL BE 15 TO 25 MPH WITH GUSTS
TO 35 MPH THRU THIS AFTN...BUT WL FALL SHORT OF ADVISORY CRITERIA.
OTHERWISE...AREAS OF LIGHT RAIN/DRIZZLE ESPECIALLY ACRS THE TRRN
WL CONT THRU THIS AFTN...BUT ADDITIONAL QPF WL BE UNDER 0.10".
TEMPS WL BE TRICKY AS STATED BEFORE WITH SOME CLRING DEVELOPING
ACRS THE SOUTHERN CPV AND TEMPS ALREADY AT 52F AT RUTLAND AND 60
AT KDDH. THIS WARMER AIR WL ADVECT NORTH INTO THE EASTERN
CPV/WESTERN SLOPES THIS AFTN. OTHERWISE...COOL NE FLW ACRS THE SLV
WL RESULT IN TEMPS ONLY IN THE U30S TO L40S. ALSO...SOME COOLER
TEMPS ANTICIPATED OVER THE SE UPSLOPE REGIONS OF THE GREENS.
INTERESTING EVENT LAST NIGHT WITH A DUSTING TO 4 INCHES OF SNOW
ACRS THE DACKS WITH SOME ICE ACCUMULATION ON POWERLINES AND TREES.
HAD SEVERAL REPORTS FROM POLICE AND MEDIA OF ISOLATED POWER
OUTAGES AND TREES DOWN DUE TO THE COMBINATION OF SNOW/ICE AND
GUSTY WINDS. SEE LATEST PNSBTV FOR FURTHER DETAILS.
QUICK UPDATE THIS MORNING TO FINE TUNE TIMING OF BACK EDGE OF
STEADIER/HEAVIER PRECIP ENDING ACRS OUR CENTRAL/NORTHERN CWA. CRNT
RADAR SHOWS STEADIER PRECIP ENDING ACRS CENTRAL VT INTO PARTS OF
THE DACKS...WHICH SHOULD CONT TO WORK NORTH TWD THE INTERNATIONAL
BORDER BY NOON. WL USE 100 POPS NORTH TO CHC POPS SOUTH THRU
NOON...THEN MENTION CHC POPS FOR THE REST OF THE DAY. TEMPS WL BE
TRICKY AND HIGHLY DEPEND UPON WINDS AND AMOUNT OF CLRING. VIS SATL
PIC SHOWS SOME BREAKS ACRS SOUTHERN VT ASSOCIATED WITH DRY SLOT
AND DEVELOPING DOWNSLOPE FLOW. THIS WL RESULT IN TEMPS WARMING
ALONG THE WESTERN SLOPES INTO THE 50S TO NEAR 60F...BUT COOL NE
FLW ACRS THE SLV WL KEEP THEM IN THE L/M40S. FOR THE CPV WL
MENTION HIGHS IN THE L/M50S AS WINDS SLOWLY SHIFT TO THE SE...WITH
MAINLY 40S FOR THE MTNS/CENTRAL VT.
HAVE CANCELLED THE WINTER WEATHER ADVISORY FOR THE NORTHERN
ADIRONDACKS AS DRY SLOT CONTINUES TO PROGRESS INTO NORTHERN NEW
YORK AND TEMPERATURES ARE SLOWLY WARMING FROM WARM AIR ADVECTION
ON THE NORTHEAST SIDE OF THE SFC LOW. FEW POCKETS OF RAIN/SNOW
MIX...AND POSSIBLY FREEZING RAIN MAY PERSIST...BUT LITTLE TO NO
ACCUMULATIONS EXPECTED AS TEMPERATURES WARM THIS MORNING.
DOWNSLOPING WINDS ON THE WESTERN SLOPES OF THE GREEN MOUNTAINS
HAS NOT COME TO FRUITION AS WINDS HAVE REMAINED 5 KTS OR LESS.
MODEL GUIDANCE SHOWS THAT THE 850MB JET HAS WEAKENED AND MOVED
NORTH...HAVE THEREFORE CANCELLED THE WIND ADVISORY FOR THAT AREA.
SUMMITS MAY STILL SEE STRONG GUSTS THIS MORNING INTO THE
AFTERNOON. ST. LAWRENCE VALLEY MAY STILL SEE SOME STRONG WIND
GUSTS AS 925MB JET HAS WEAKENED TO 30-45 KTS...BUT REMAINS OVER
THAT AREA THROUGH THE MORNING HOURS. HAVE KEPT THE WIND ADVISORY
OVER THE ST. LAWRENCE VALLEY FOR NOW.
OTHERWISE...PRECIPITATION MOVING INTO SOUTHERN VERMONT AND THE
CHAMPLAIN VALLEY MORE SHOWERY IN NATURE.
PREVIOUS DISCUSSION...ENHANCED CLOUD TOPS AND STRONG RADAR
REFLECTIVITIES OVER ADIRONDACKS IN NORTHERN NEW YORK WELL PROGGED
BY GFS FGEN. NAM SHOWING BEST FGEN MORE EAST...BUT BOTH MODELS
SHOW THIS FEATURE MOVING NORTH OUT OF THE AREA AS IT WEAKENS THIS
MORNING. WINTRY MIX AFFECTING THE NORTHERN ADIRONDACKS WITH
MAINLY SNOW OR RAIN AFFECTING THE ST LAWRENCE VALLEY.
TEMPERATURES GENERALLY WARMER AS YOU HEAD EAST...WITH RAIN
AFFECTING THE CHAMPLAIN VALLEY AND MOST OF VERMONT. TEMPS WILL
GRADUALLY WARM THIS MORNING WITH ANY WINTRY PRECIP CHANGING TO
ALL RAIN DURING THE DAY.
DRY SLOT SLOWLY ADVANCING NORTH FROM EASTERN NY THIS MORNING WILL
LEAD TO FEW BREAKS AND GENERALLY DECREASING POPS OVER THE NORTH
COUNTRY. AS SFC LOW SLOWS NEAR LAKE ONTARIO...NORTHERN NY LIKELY
TO SEE MORE PRECIP TODAY.
TYX RADAR WIND PROFILE SHOWING 40 KTS AT LOWEST LEVELS PERSISTING
EARLY THIS MORNING. LLJ OVER THE ST LAWRENCE VALLEY WEAKENING
DURING THE DAY WITH GUSTS IN THE MORNING OF 30-40 KTS DECREASING
TO LESS THAN 30 KTS THIS AFTERNOON. WIND NOT MIXING DOWN OFF THE
GREENS THIS MORNING WITH 850MB JET PROGGED TO WEAKEN QUICKLY
EARLY TODAY. LLJ ALSO LOOKS TO SHIFT MORE SOUTHERLY
TODAY...LIMITING DOWNSLOPING.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
AS OF 502 AM EDT MONDAY...POTENTIAL FOR GUSTY WINDS EXISTS THROUGH
TUESDAY...BUT LLJ MUCH WEAKER. SFC LOW WILL PIVOT LATE TONIGHT
INTO TUESDAY...BRINGING A SURGE OF PRECIP OVER NORTHERN NY. THIS
WILL ALSO BRING IN COOLER TEMPERATURES...ESPECIALLY ALOFT...WITH
NEGATIVE SINGLE DIGIT TEMPS AT 850MB AND 925MB OVER NORTHERN NY
AND EDGING INTO VERMONT TONIGHT. WITH THESE COOLER TEMPS...CAN
EXPECT GREATER CHANCE FOR ANY PRECIP OVERNIGHT TO BE RAIN/SNOW MIX
TO ALL SNOW OVER THE ADIRONDACKS. SNOWFALL AMOUNTS OVERNIGHT WILL
RANGE FROM A DUSTING TO LESS THAN ONE INCH. THE COOLER AIR ALOFT
WILL LEAD TO COOLER MAX TEMPS ON TUESDAY...WITH HIGHS IN THE 40S
TO LOW 50S.
THE FAIRLY STACKED LOW WILL GAIN MOMENTUM NORTHWARD LATE TUESDAY
AND TUESDAY NIGHT WITH DECREASING CHANCES FOR PRECIP AS THE
DAY/NIGHT GO ON. THERES STILL A CHANCE FOR SNOW SHOWERS TUESDAY
NIGHT MAINLY OVER THE HIGHER TERRAIN WITH LESS THAN ONE INCH
ACCUMULATION EXPECTED AT THIS TIME.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 434 AM EDT MONDAY...SIMILAR TO THINKING SUNDAY AT THIS
TIME...MONDAY/S CLOSED SYSTEM WEAKENING AND BECOMING ABSORBED BY
CLOSED LOW IN JAMES BAY BUT WILL EVENTUALLY RETURN IN A DIFFERENT
FASHION LATER THIS WEEK AND EARLY NEXT WEEKEND. WINTER IN LATE
APRIL AFTER SUMMER IN MID-MARCH...GO FIGURE?!
AGAIN...TROFINESS HANGS ON WED WITH LESSENING CHC OF -SHRA EACH
MOMENT. OVERALL FLOW PATTERN STILL NW AND CYCLONIC BACKING
TOWARD W AND SW AHEAD OF NEXT STG S/W ROTATING ARD HUDSON BAY CLOSED
LOW WHICH WILL BRING A SERIES OF COLD FRONTS AND -SHRA THREAT ON
THU/THU NGT AND PSBLY FRI. THERE/S BEEN A ONGOING CHANGE HERE...
ALL MODELS ARE COMING INTO PHASE OF A STG NRN STREAM S/W ROTATING
INTO FA WITH SFC LOW DEVELOPMENT THU AFTN-FRI WHICH WILL BRING MORE
OF A STEADY PCPN VS SHOWERY WITH PERHAPS SOME SNOW AS WELL.
THEREAFTER...COLD NNW FLOW AND SFC HIGH DIRECTLY FM POLAR REGIONS
MOVES INTO FA FOR SAT/SUN. MIN/MAX TEMPS FOR FRI/SAT ARE FCST 10+
DEGS BLO NORMAL (DAYS 6/7) WHICH MEANS CUD BE COLDER.
THERE ARE STILL QUESTIONS FOR SUNDAY AS A LEFTOVER BOUNDARY FM
THU/FRI SYSTEM LIES JUST S OF SNE WITH ANOTHER NRN STREAM S/W
ROTATING SE TOWARD GRT LAKES AND POSSIBLE SFC LOW DVLPMNT ALG THIS
BOUNDARY WITH A THREAT OF RAIN ACRS SRN FA.
FROST/FREEZE PROGRAM BEGINS IN CHAMPL VLY/ST LWRNC VLY APRIL
25TH...APPROX 10 DAYS EARLY DUE TO ABNORMALLY WARM WINTER/SPRING AND
HORTICULUTURE SEASON RUNNING WEEKS EARLY.
BEGINNING/ENDING FROST/FREEZE PROGRAM IS ALWAYS PROBLEMATIC DUE TO
DIFFERENT CLIMATE REGIONS ACROSS CWA. IT WILL ACTUALLY BE COLDER IN
INTERIOR VERMONT AND NORTHERN NY YET DUE TO THE START OF THE PROGRAM
BEING MAY 5TH AND MAY 15TH THERE WUD BE NO HEADLINES.
HEADLINES OR NOT...IF TEMPERATURES GET INTO THE 20S/L30S PROTECTION
OF ANY CROPS/PLANTS NEED TO BE TAKEN. APPLE ORCHARDS AND WINE
VINEYARDS ARE AT A SUSCEPTIBLE POINT WITH TEMPS IN THE M20S POSSIBLY
CAUSING DEVASTATING EFFECTS.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
THROUGH 12Z TUESDAY...WIDESPREAD MVFR/IFR CONDITIONS EXPECTED
THROUGH THE PERIOD. HEAVIEST PCPN BEHIND US BUT STILL LOW CIGS.
NORTHEAST-EAST WINDS WILL BE PEAKING THRU 12-15Z THEN GRADUALLY
DECREASING WITH STRONGEST AT KMSS WITH SOME 25-30 KNOT GUSTS
POSSIBLE.
WEAK UPR LEVEL FLOW WITH CLOSED LOW TONIGHT WILL LIKELY MEAN
PERSISTENT OR SLIGHTLY LOWERING CIGS IFR/MVFR AS WELL AS POSSIBLE
MVFR/IFR VSBY.
OUTLOOK 12Z TUESDAY THROUGH FRIDAY...
12Z TUESDAY THROUGH 00Z THURSDAY...VFR WITH PERIODS OF MVFR/IFR IN
SCATTERED RAIN/SNOW SHOWERS WITH UPPER LEVEL LOW...ESPECIALLY AT
SLK/MPV.
00Z THURSDAY THROUGH 12Z THURSDAY...PRIMARILY VFR BETWEEN
STORM SYSTEMS.
12Z THURSDAY THROUGH FRIDAY...VFR WITH PERIODS OF MVFR/IFR IN
RAIN/SNOW SHOWERS WITH FRONTAL SYSTEM...ESPECIALLY SLK/MPV.
&&
.MARINE...
AS OF 445 AM EDT MONDAY...LAKE WIND ADVISORY IS IN EFFECT FOR
TODAY...ESPECIALLY THE MORNING.
NORTH WINDS OF 15 TO 25 WILL CONTINUE THROUGH MID-MORNING BEFORE
DECREASING TO 10 KNOTS THIS AFTERNOON.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...KM
NEAR TERM...KM/TABER
SHORT TERM...KM
LONG TERM...SLW
AVIATION...RJS/SLW
MARINE...
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1037 AM EDT MON APR 23 2012
.SYNOPSIS...
BREEZY AND COOL CONDITIONS WILL PREVAIL TODAY AS CANADIAN HIGH
PRESSURE BUILDS INTO THE AREA. BELOW NORMAL TEMPERATURES THROUGH
EARLY WEDNESDAY WILL BE FOLLOWED BY A WARMING TREND LATE IN THE
WEEK AHEAD OF AN APPROACHING COLD FRONT. A WEAK FRONT ON FRIDAY
MAY BE FOLLOWED BY A STRONGER COLD FRONT NEXT SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 AM MONDAY...COLD POOL ALOFT AND ATTENDANT STEEP LAPSE
RATES ARE COMBINING WITH LOWER LEVEL MOISTURE TO FORM A RATHER
EXTENSIVE CU FIELD...ESPECIALLY OVER OUR NORTHERN COUNTIES WHERE
IT IS THICKENING UP NICELY. LATEST HRRR RUN AND SOME OTHER
GUIDANCE SHOWS ISOLATED AFTERNOON SHOWERS OVER THESE AREAS OF
GREATEST CLOD COVER IS STILL A POSSIBILITY FOR THIS AFTERNOON.
WILD CARD COULD BE WHETHER WE GET TOO MUCH CLOUD COVER...THUS
KEEPING SURFACE TEMPS TOO LOW FOR CONVECTION. WIND PROFILES SHOW
ANY SHOWERS THAT DO FORM COULD PULL DOWN SOME HEFTY GUSTS.
PREVIOUS DISCUSSION FOLLOWS:
SEVERAL OF THE RAPID UPDATE MODELS ARE NOW POINTING TO MID-LATE
AFTERNOON SHOWERS BENEATH THE COLD POOL ALOFT DESPITE THE DRY SUB-
CLOUD AIR. HAVE UPDATED ZONES TO ACCOUNT FOR THIS POTENTIAL. ANY
SHOWERS WILL BE CAPABLE OF IMPARTING GUSTY W AND WNW WINDS TO THE
SURFACE...DUE TO THE INVERTED-V PROFILE OF AFTN SOUNDINGS. THE
PREVIOUS MORNING DISCUSSION FOLLOWS.
PICTURES FROM SPACE EARLY THIS MORNING SHOW STRONG LOW PRESSURE
SLAMMING INTO THE SOUTHERN NEW ENGLAND COAST DRIVEN BY A COLD POOL
ALOFT MOVING INTO THE CENTRAL APPALACHIANS. THESE FEATURES
INTERACTING WITH BUILDING HIGH PRESSURE FROM THE MISSISSIPPI VALLEY
WILL DRIVE A BRISK WNW WIND FLOW TODAY ACROSS THE AREA. SURFACE
ANALYSIS SHOWS FALLING DEWPOINTS PUSHING SE OVER MUCH OF THE SE AND
MID-ATLC...WITH BOTH NAM-12 AND THE EURO MODEL SHOWING TD VALUES IN
THE 30S BY MID AFTERNOON OVER OUR AREA.
MAXIMUMS LOW-MID 60S THIS AFTN...POSSIBLY MILDEST OVER EASTERN ZONES
WHERE DOWNSLOPE COMPONENT TRAVELS FARTHEST. AFTER CLEARING WE WILL
LIKELY SEE AFTERNOON CUMULUS BENEATH THE COLD POOL AMID SHARP LAPSE
RATES. THE CU COULD BECOME MODERATE AND CAPABLE OF GENERATING A FEW
SHOWERS IN GUSTY WINDS BETWEEN 3-6 PM.
PATCHY FROST REMAINS A THREAT EARLY TUESDAY...WITH LOWS IN THE
MIDDLE TO UPPER 30S OVER PROTECTED AREAS FROM W WIND FLOW. NO
FROST ADVISORY PLANNED THIS PACKAGE SINCE VAST UNCERTAINTY
EXISTS ON SPATIAL COVERAGE OF FROST...BUT A COURTESY SPS AT A
MINIMUM WOULD SEEM APPROPRIATE LATER TODAY.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3:00 AM MONDAY...DEEP EAST COAST TROUGH WILL CONTINUE TO BE
THE STORY AT LEAST FOR ONE MORE DAY BEFORE LIFTING OUT AS THE
PATTERN FLATTENS BY EARLY THURSDAY.
MAIN FORECAST CHALLENGE EVOLVES AROUND POPS FOR LATE TUESDAY INTO
WEDNESDAY AM WITH THE LAST OF THE FORMIDABLE EMBEDDED SHORTWAVES
MOVING ACROSS. NWP GUIDANCE HAS BEEN TRENDING A BIT MORE AGGRESSIVE
WITH THIS FEATURE AND HAVE ADDED SLIGHT CHANCE POPS CENTERED AROUND
0600 UTC WEDNESDAY FROM SOUTH TO NORTH FOLLOWING THE GFS. THE NAM
HAS THE FEATURE BUT DEVELOPS ACTIVITY A BIT MORE OFFSHORE. WEDNESDAY
SHOULD BE SUNNY ALTHOUGH IT IS WORTH NOTING THE NAM HAS YET ANOTHER
SHORTWAVE THAT WOULD CERTAINLY CHANGE THE FORECAST IF IT VERIFIES.
TEMPERATURE GUIDANCE IS STABLE WITH THE ONLY REAL CHALLENGE BEING
WEDNESDAY MORNING LOWS WHERE I CONTINUED TO GO SLIGHTLY ABOVE
GUIDANCE WITH A MIXED BOUNDARY LAYER.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3:00 AM MONDAY...EXTENDED WARRANTS FEW CHANGES
THIS MORNING AS THE MEDIUM RANGE MODELS ARE RELATIVELY UNCHANGED.
INITIAL OMEGA PATTERN WILL DEVELOP INTO A MODEST RIDGE BY THE END
OF THE PERIOD OVER THE SOUTHEAST. ONLY SURFACE FEATURE OF NOTE IS
THE BACKDOOR FRONT SLATED FOR A LATE THURSDAY/EARLY FRIDAY PASSAGE
ACROSS OUR AREA. MAINTAINED THE SLIGHT CHANCE POPS FOR THIS FEATURE
THURSDAY AND THROUGH SATURDAY AS THE ECMWF...THE PREFERRED SOLUTION
FROM HPC SHOWS INDICATIONS OF THE BOUNDARY LINGERING ACROSS SOUTHERN
ZONES. NO CHANGES TO TEMPERATURE GUIDANCE WHICH SHOW THE LARGEST
DEVIATION FROM NORMAL...ON THE WARM SIDE FRIDAY MORNING...OTHERWISE
NOTHING REALLY OUT OF THE ORDINARY.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
AS OF 12Z...PRECIP ASSOCIATED WITH A TROUGH ROTATING AROUND THE
UPPER LOW HAVE MOVED OFFSHORE. COLD CORE WILL MOVE OVERHEAD THIS
AFTERNOON. MODELS INDICATE THERE WILL BE ENOUGH MOISTURE TO PRODUCE
INSTABILITY SHOWERS THIS AFTERNOON...BEGINNING NEAR MAX HEATING.
COVERAGE WILL BE LIMITED...SO ONLY A VCSH MENTION. IF A TERMINAL
MANAGES TO GET A SHOWER...TEMPERATURE COULD DROP BY TEN DEGREES OR
MORE WITH SQUALLY TYPE WINDS. EVEN WITHOUT THE CONVECTION...WINDS
WILL GUST WELL INTO THE TWENTIES TODAY...DIMINISHING THIS EVENING.
EXTENDED OUTLOOK...VFR WITH LOW CHANCES OF PRECIPITATION THROUGH THE
PERIOD.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 AM MONDAY...CONDITIONS OVER THE WATERS CONTINUE TO BE
JUST BAD ENOUGH TO WARRANT A SMALL CRAFT ADVISORY. COLD SURGE OVER
THE WATERS CREATING FREQUENT GUSTS UP AROUND 25 KTS. COASTAL AND
BUOY OBS SHOW SEAS IN THE 4 TO 6 FT RANGE. NO CHANGES TO EARLIER
THINKING...WHICH IS DETAILED IN PREVIOUS DISCUSSION BELOW:
ADVISORIES WILL BE NEEDED TODAY FOR GUSTY NW WINDS BEHIND AN
EXITING COLD FRONT. GUSTS TO 25-30 KT SHOULD BE EXPECTED
TODAY...AND INTO VERY EARLY EVENING OVER OUR NORTHERN WATERS WHERE
THE PRESSURE GRADIENT WILL BE A BIT MORE CRAMPED. INSHORE SEA-
HEIGHTS WILL SUBSIDE AS THE OFFSHORE FLOW PREVAILS. NO TSTMS
EXPECTED ON THE 0-20NM WATERS AS DRIER AIR SPREADS OVER THE AREA.
PATCHY DZ EARLY WILL TRACK ACROSS THE WATERS INTO DAWN. RESIDUAL
SE WAVES WILL CO-MINGLE WITH NW WIND-WAVES TODAY MAKING FOR A
BUMPY AND HAZARDOUS SEAS TODAY.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3:00 AM MONDAY...BLUSTERY CONDITIONS CONTINUE FOR AT LEAST ONE
MORE DAY FOR THE MARINE COMMUNITY AS A STRONG SHORTWAVE MOVES ACROSS
IN THE MEAN FLOW LATE TUESDAY. EXPECT WEST TO SOUTHWEST WINDS OF
15-20 KNOTS FOR MOST OF THE DAY TUESDAY TURNING TO NORTHWEST BY
WEDNESDAY MORNING AS THE ASSOCIATED SURFACE TROUGH MOVES ACROSS.
PATTERN RELAXES A BIT WEDNESDAY AND WIND DROP TO WESTERLY AROUND
TEN KNOTS. THE HIGHER SEAS...FIVE FEET...REMAIN CONFINED TO OFFSHORE
WATERS WITH 2-4 FEET ACROSS THE COASTAL ZONES. BY WEDNESDAY EVENING
SEAS SHOULD BE AROUND TWO FEET ACROSS ALL WATERS.
LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3:00 AM MONDAY...THURSDAY THROUGH FRIDAY...MAIN FEATURE WILL BE
THE FRONT MOVING ACROSS THE WATERS EARLY FRIDAY WITH A WIND SHIFT
FROM SOUTHWEST TO NORTHWEST. WINDS VEER FURTHER TO THE EAST LATER
FRIDAY BUT SPEEDS SHOULD REMAIN TEPID AS THERE IS LITTLE COLD AIR
ADVECTION. SEAS INCREASE FROM 3-5 FEET EARLY TO 5-7 FEET MOSTLY
CONFINED TO THE OUTER WATERS LATE THURSDAY AS A STRONG SOUTHWEST
FLOW DEVELOPS AHEAD OF THE PREVIOUSLY MENTIONED BOUNDARY. SEAS DROP
APPRECIABLY LATER FRIDAY WITH THE CHANGE IN FETCH.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR AMZ254-
256.
SMALL CRAFT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR AMZ250-
252.
&&
$$
SYNOPSIS...REK/SHK
NEAR TERM...MJC/REK
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DL
MARINE...MJC/REK/SHK
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
653 AM EDT MON APR 23 2012
.SYNOPSIS...
DEVELOPING LOW PRESSURE SYSTEM MOVES NORTH ALONG THE MID ATLANTIC
COAST THROUGH TODAY. UPPER LEVEL LOW MOVES SOUTHEAST THIS MORNING. A
CLIPPER LIKE SYSTEM WILL AFFECT THE AREA BY MID WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
RADAR IMAGES SHOW A BATCH OF MAINLY RAIN UNDER TEMPERATURES ABOVE
35 DEGREES...MOVING FROM CENTRAL TO SOUTHEAST WV EARLY THIS
MORNING. SFC OBS OVER HIGHER ELEVATIONS INDICATE TEMPERATURES
BELOW 33 DEGREES REPORTING SNOW. THE HIGH RESOLUTION HRRR MODEL
DEPICTS THIS FEATURE VERY GOOD. IT ALSO INDICATE A SECOND BATCH OF
PCPN DIGGING SOUTH ACROSS THE EASTERN HALF OF THE AREA BY 16-17Z.
WITH TEMPERATURES STAYING BELOW FREEZING...EXPECT RELAY ON THIS
MODEL...SUPPORTED BY THE RUC13 ON THIS SECOND BATCH OF SNOW FOR
THE EASTERN MOUNTAINS.
HIGHEST ELEVATIONS OF POCAHONTAS COUNTY ALREADY WITH ONE INCH OF
SNOW DEPTH. EXPECT HEAVY WET SNOW TO REALLY PICK UP OF THE THE
WARNING COUNTIES FROM 8 AM TO 4 PM THIS AFTERNOON...AS SUGGESTED
BY MODELS.
MINOR CHANGES MADE TO POPS/WEATHER GRIDS. NO CHANGES MADE TO
WINTER WARNING AND ADVISORIES.
EXPECT A TEMPERATURE GRADIENT FROM THE LOWER 50S NEARBY HTS...AND
NORTHEAST KY...RANGING TO THE LOWER 30S NORTHEAST MOUNTAINS FOR
HIGHS TODAY.
COLD TEMPERATURES TONIGHT MAY NEED A FREEZE WARNING FOR EASTERN
MOUNTAINS AND PORTIONS OF NORTHERN WV.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
GENERALLY WENT WITH GFS/SREF/ECMWF MODEL BLEND THROUGH THIS
PERIOD...WITH NAM BEING THE OUTLIER. SFC LOW OVER NORTHERN GREAT
LAKES WILL CONTINUE TO MOVE NORTHWARD AND ITS AFFECTS WILL DEPART
WITH IT...BUT KEPT SOME LINGERING MOISTURE AND POPS IN THE
NORTHERN MOUNTAIN ZONES DURNING THE DAY ON TUESDAY...WITH GRADUAL
DECREASE. A WEAK UPPER LEVEL SYSTEM SLIDES SOUTH OF THE CWA ON
TUESDAY AS WELL...WITH MOST OF THE ENERGY STAYING SOUTH OF CWA. IN
ANY CASE KEPT SLGHT CHC POPS ACROSS EXTREME SW AND SRN PORTION OF
CWA ON TUESDAY AS WELL. BRIEF BREAK BEFORE MORE VIGOROUS SYSTEM
MOVES DOWN FROM THE UPPER MIDWEST AND TRACKS ACROSS THE CWA
WENDESDAY NIGHT AND THURSDAY. TEMPERATURES WILL GRADUALLY WARM
TRHOUGH THE PERIOD AS SOUTHERLY FLOW WILL INCREASE ON TUESDAY AND
WEDNESDAY.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
UNSETTLED WEATHER EXPECTED IN THE LONG TERM. CLIPPER TYPE SYSTEM
WILL MOVE THROUGH THE REGION ON THURSDAY...BRINGING ANOTHER ROUND OF
SHOWERS AND THUNDERSTORMS. COLD FRONT ASSOCIATED WITH THIS SYSTEM
WILL PUSH THROUGH THE AREA LATE THURSDAY...BEFORE STALLING TO OUR
SOUTH ON FRIDAY AS HIGH PRESSURE BRIEFLY BUILDS IN FROM THE
NORTH...PROVIDING A BRIEF BREAK IN THE WEATHER. AS USUAL...QUITE A
BIT OF UNCERTAINTY IN THE LATTER PART OF THE EXTENDED...BUT APPEARS
AS THOUGH ANOTHER WAVE OF LOW PRESSURE WILL PUSH THROUGH THE AREA BY
SUNDAY...BRINGING YET ANOTHER ROUND OF PRECIPITATION TO THE AREA.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
TRIED TO PINPOINT PCPN TRANSITION FROM RAIN...TO MIXED WITH
SNOW...TO ALL SNOW ACROSS EKN...PKB AND BKW MONDAY MORNING. SNOW
SHOWERS WILL AFFECT THESE SITES THROUGH AT LEAST 21Z MONDAY. OTHER
SITES WILL EXPERIENCE VFR/MVFR DRIZZLE WITH OCCASIONAL WEST TO
NORTHWEST FLOW...THROUGH THE PERIOD.
INCORPORATED SREF PROBABILITIES FOR IFR/LIFR LOW CEILINGS ACROSS
THE MOUNTAINS REFINING WITH MESOSCALE AND MICROCLIMATE EFFECTS
OVER HIGHEST ELEVATIONS AND UPSLOPE AREAS. HAVE WORST CONDITIONS
AT CKB...EKN AND BKW FROM 12-149Z. BUT CONTINUING AT EKN AND CKB
THROUGH 21Z UNDER SNOW SHOWERS.
IN THE LOWLANDS...CONDITIONS WILL START TO IMPROVE TO VFR MON AFTERNOON AS
THE PRECIPITATION TAPERS OFF.
IN THE MOUNTAINS...HIGH RESOLUTION MODELS INDICATED A SECOND BATCH
OF PCPN MOSTLY SNOW SHOWERS OVER THE EASTERN MOUNTAINS BY 17Z. CONDITIONS
MAY START TO IMPROVE TO MVFR AS RAIN AND SNOW MIXED STARTS TO
TAPER OFF LATE THIS EVENING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z TUESDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: HEAVIER SNOW SHOWERS MAY CAUSE FURTHER
REDUCTION IN CIG AND VSBY VALUES. TIMING OF PRECIP ONSET AND IFR /
LIFR IN SNOW MAY VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M H H H H H M H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY M M M M M L M L L M M M
EKN CONSISTENCY M M M M M M M M L L L L
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY M M H L H H L M L M M M
AFTER 12Z TUESDAY...
IFR CONDITIONS IN MOUNTAIN SNOW AND LINGERING LOW CLOUDS MON
NIGHT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...WINTER WEATHER ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR WVZ032-
037>040.
WINTER STORM WARNING UNTIL MIDNIGHT EDT TONIGHT FOR WVZ046-047.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...JS/ARJ
NEAR TERM...ARJ
SHORT TERM...JS
LONG TERM...SL
AVIATION...ARJ
AREA FORECAST DISCUSSION
NWS PORTLAND OR
220 PM PDT MON APR 23 2012
.SYNOPSIS...NEAR RECORD WARMTH THIS AFTERNOON AND ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS NEAR THE CASCADE CREST WILL GIVE
WAY TO COOLER AND MORE SHOWERY WEATHER ON TUESDAY. AN UPPER LEVEL
TROUGH WILL BRING HEAVIER AND PERSISTENT SHOWERS AT TIMES...AND
COOLER THAN NORMAL TEMPERATURES TO WESTERN OREGON AND WASHINGTON LATE
WEDNESDAY INTO THURSDAY. COOL WEATHER AND LIGHT SHOWERS WILL LIKELY
PERSIST INTO THE WEEKEND.
&&
.SHORT TERM...VISIBLE SATELLITE IMAGERY SHOWS CUMULUS BEGINNING TO
POP ACROSS SOUTHWESTERN OREGON. MUCH OF THE FORECAST AREA REMAINS
CLEAR AND CAPPED...BUT THIS SHOULD CHANGE IN THE NEXT FEW
HOURS...PARTICULARLY SOUTH AND EAST OF EUGENE WHERE THUNDERSTORMS
SHOULD BEGIN TO DEVELOP. STORMS WILL GENERALLY MOVE IN A
NORTH-NORTHEASTERLY DIRECTION AND TREND INTO PENDLETONS FORECAST
AREA EAST OF THE CASCADES THIS EVENING. NONETHELESS...A SEVERE STORM
OR TWO WILL BE POSSIBLE ON OUR SIDE OF THE MOUNTAINS BEFORE CROSSING
EAST OF THE CASCADES GIVEN THE INSTABILITY AND SHEAR.
A PUSH OF COOLER...MORE STABLE MARITIME AIR WILL SPILL INTO THE
WILLAMETTE VALLEY THIS EVENING. HRRR CONTINUES TO BRING THIS INTO THE
VALLEY BETWEEN 5-7PM. THIS BOUNDARY MAY PROVIDE ENOUGH LIFT TO POP A
THUNDERSTORM OUT AHEAD OF THE MAIN ACTION THAT DEVELOPS TO THE SOUTH
AND EAST OF EUGENE. ALTHOUGH...NONE OF THE CURRENT MODEL RUNS DEPICT
THIS HAPPENING AT THIS TIME. THE HRRR WOULD SUGGEST THE BEST THREAT
FOR AN OUTFLOW FROM AN EXISTING STORM TO INITIATE A NEW STORM OVER
THE NORTHERN WILLAMETTE VALLEY WOULD BE LATE THIS EVENING...BUT
CONFIDENCE IS VERY LOW IN THIS ACTUALLY OCCURRING.
LOW CLOUDS AND LIGHT SHOWERS WILL BE THE NORM FOR TUESDAY AS ONSHORE
FLOW STRENGTHENS. A LOW PRESSURE IN THE GULF OF ALASKA WILL THEN DROP
SOUTHWARD AND AN ELONGATED FRONT WILL APPROACH THE REGION ON
WEDNESDAY. SOUTHWEST FLOW AHEAD OF THE MAIN FRONTAL BAND WILL BRING
RAIN SHOWERS TO THE REGION...BEGINNING TUESDAY NIGHT INTO WEDNESDAY.
A THIRD TO TWO THIRDS OF AN INCH OF RAIN APPEARS PROBABLE ACROSS THE
VALLEYS BY THURSDAY. COOLER THAN NORMAL TEMPERATURES WILL RETURN BY
THURSDAY AS WELL. /NEUMAN
.LONG TERM...THURSDAY EVENING THROUGH SUNDAY...MODELS AGREE ON THE
DEVELOPMENT OF A FLAT UPPER LEVEL RIDGE OVER THE EASTERN PACIFIC AT
THE END OF THE WEEK AND THROUGH THE WEEKEND. A SYSTEM CRESTS THE
RIDGE AND MOVES INTO THE PACIFIC NORTHWEST LATE FRIDAY WITH SHOWERS
LINGERING THROUGH THE SATURDAY. THOUGH TIMING DIFFERENCES EXIST...
THE GFS AND THE ECMWF BOTH SHOW A POSSIBILITY OF DRIER WEATHER
SUNDAY...AND THE CANADIAN TO A LESSER EXTENT. THE FLATTENED RIDGE
ALLOWS ANOTHER SYSTEM TO APPROACH THE PACIFIC NORTHWEST AND BRING
RAIN EARLY NEXT WEEK. KELSON
&&
.AVIATION...IFR STRATUS AND FOG HAS DISSIPATED ALONG THE NORTHERN
COAST AND HAS DISSIPATED TO THE BEACHES ALONG THE CENTRAL COAST. THE
FOG/LOW STRATUS IS EXPECTED TO RETURN THIS EVENING AS LOW MVFR/IFR
CIGS. INLAND AREAS...VFR CONDITIONS THIS AFTERNOON/EVENING. SOMEWHAT
UNSTABLE CONDITIONS WITH LOW CHANCES OF THUNDERSTORMS OVER THE
INLAND VALLEYS WITH GREATER CHANCES OVER THE CASCADES AND COAST
RANGE. SOUTHWEST ONSHORE FLOW INCREASES TONIGHT...WITH THE MARINE
AIR MASS SPREADING INLAND GIVING MVFR CIGS AROUND 2000 FEET.
KPDX AND APPROACHES...VFR CONDITIONS THIS AFTERNOON/EVENING WITH
ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS. MVFR CIGS EXPECTED
AFTER 10Z TUE AS MARINE STRATUS MOVES INLAND.
&&
.MARINE...NORTHERLY WINDS INCREASING AS A RIDGE OF HIGH PRES BUILDS
OVER THE OFFSHORE WATERS. WINDS AND SEAS RATHER BENIGN THROUGH
TUE...WITH WINDS UNDER 20 KT AND SEAS REMAINING UNDER 7 FT. NEXT
THREAT FOR SMALL CRAFT WINDS COMES WED WHEN A COLD FRONT APPROACHES.
&&
.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 STATE COLLEGE PA
156 AM EDT MON APR 23 2012
.SYNOPSIS...
LOW PRESSURE CENTERED JUST EAST OF NORFOLK VIRGINIA THIS EVENING
GRADUALLY INTENSIFY AS IT PUSHES TO THE NORTH THEN NORTHWEST
OVERNIGHT AND MONDAY...REACHING THE FINGER LAKES REGION OF NEW
YORK STATE LATE MONDAY. COLDER AIR BEING PULLED SOUTH INTO
WESTERN AND CENTRAL PENNSYLVANIA WILL CHANGE THE RAIN OVER TO
HEAVY WET SNOW ACROSS THE NORTHWEST HALF OF THE STATE DURING THE
OVERNIGHT HOURS. THE HEAVIEST SNOW IS EXPECTED ON THE HIGHER
ELEVATIONS OF NORTH CENTRAL AND NORTHWESTERN PENNSYLVANIA...AND
THE LAUREL HIGHLANDS. HEAVY WET ACCUMULATIONS OF SNOW WILL PRODUCE
WIDESPREAD TREE DAMAGE AND LEAD TO POWER OUTAGES. IMPROVING...BUT
STILL UNSETTLED CONDITIONS WILL FOLLOW FOR TUESDAY AND WEDNESDAY
AS THE COLDEST AIR RETREATS NORTHWARD AND A FAST WESTERLY FLOW
ALOFT DEVELOPS.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
EVENT QPF WILL BE LESS DUE TO MORE PROGRESSIVE EVOLUTION OF
NEGATIVE TILT CUTOFF...AND SFC LOW TRACK TO THE CATSKILLS BY 18Z MON.
COLD CONVEYOR BELT SNOWS NOT AS IMPRESSIVE AS A RESULT...AND HAVE
BEGUN THE PROCESS OF CUTTING BACK AMOUNTS OVER THE LAURELS... WEST
CENTRAL MOUNTAINS AND NORTHWEST MOUNTAINS. LOWER END AMOUNTS
REMAIN THE SAME FOR NOW...BUT WILL WATCH EVOLUTION OVERNIGHT AND
BE PREPARED FOR MORE CHANGES IN THE PRE DAWN HOURS.
DUAL POL CORRELATION COEFFICIENT PRODUCT NICELY INDICATES THAT THE
PRECIP HAS CHANGED OVER TO WET SNOW AT THE BEAM HEIGHT OF
2500-3000 MSL JUST TO THE EAST OF THE RDA...WHILE THIS CC PRODUCT
AND SFC OBS INDICATES THAT THE CHANGEOVER HAS REACHED THE GROUND
ACROSS THE NW MTNS. KDUJ AND KBFD CHANGED TO SNOW BETWEEN 00Z AND
01Z...WHILE KFIG AND KJST JUST WENT OVER TO ALL SNOW WITHIN THE PAST
30 MINUTES. SOME WET SNOW FLAKES HAVE BECOME MIXED IN AROUND THE
HAPPY VALLEY AREA...AND A CHANGOVER TO HEAVY WET SNOW SHOULD OCCUR
FROM KAOO TO KUNV BETWEEN 03Z-05Z BASED ON THE 01Z RUC FCST OF MEAN
925-850 MB WET BULB TEMPS DIPPING SLIGHTLY TO JUST -0.5 TO -1C.
MIXED PHASE PRECIP IS NOTED AT ELEVATIONS AS LOW AS 4500 FT MSL TO
THE EAST THROUGH SSE /AT FURTHER DISTANCES AWAY FROM THE RADAR
SITE/...HIGHLIGHTING THE STRONG EAST TO WEST MID LEVEL TEMP GRADIENT
FROM THE CENTRAL MTNS TO THE SUSQ VALLEY.
THE BACK /SWRN EDGE/ EDGE OF THIS CURRENT PRECIP SHIELD WILL
LIKELY EXPAND TO THE SW...AND PIVOT SLOWLY WWD ACROSS THE
COMMONWEALTH OVERNIGHT AND TUESDAY MORNING WITH PRECIP RATES BEING
MAINTAINED OR EVEN INCREASING ACROSS THE CENTRAL MTNS AND
ALLEGHENY PLATEAU...LEADING TO HEAVY WET SNOW WITHIN A FEW
QUASI-SNTRY BANDS OF MDT TO STG FRONTOGENESIS.
NO APPRECIABLE CHANGE WAS MADE TO THE GRIDDED FCST DATABASE WITH
RESPECT TO THE TIMING OF THE RAIN TO SNOW CHANGEOVER...AND
RESULTANT SNOW ACCUMS BY 12Z MONDAY. WILL BE KEEPING A WATCHFUL
EYE THOUGH ON THE HIGH TERRAIN OF SULLIVAN COUNTY /NE OF
KIPT/...SINCE THEY/RE CURRENTLY ONLY IN THE MID 30S WITH WEAK LLVL
COLD ADVECTION CONTINUING. HOWEVER...WARMER AIR SURGING IN ALOFT
FROM THE SSE SHOULD LIMIT ANY CHANGEOVER FOR MUCH OF THE NIGHT TO
JUST A MIX OF WET SNOW AND SLEET AT BEST.
THE RAINFALL IN THE EAST HAS BEEN A STEADY/MODERATELY HEAVY COLD
RAIN FALLING AT A RATE OF GENERALLY 102 TENTHS OF AN INCH PER
HOUR. THE VERY DRY ANTECEDENT CONDITIONS AND EARLY GREEN-UP WILL
ABLE TO EASILY HANDLE THIS RATE...AND TOTAL FCST RAINFALL OF 1-2
INCHES...WITH MINOR TO AT MOST MODERATE RISES ON SMALLER STREAMS
OVER...AND TO THE EAST OF THE SUSQ MAINSTEM.
THE RAIN WILL BE TAPERING OFF IN THE EAST BETWEEN 05Z AND 09Z
MONDAY.
LOW TEMPS OVERNIGHT WILL RANGE FROM THE LOWER 40S IN THE SE
ZONES...TO AROUND 30 ACROSS THE HIGHEST TERRAIN OF THE WEST.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
PERIODS OF MDT TO HEAVY WET SNOW WILL PERSIST ACROSS THE NW MTNS
AND LAUREL HIGHLANDS FOR MUCH OF MONDAY AS THE UPPER LOW TURNS NE
AND LIFTS ACROSS CENTRAL PENN. A MIX OF WET SNOW...AND RAIN IS
STILL EXPECTED IN THE LOWER ELEVS OF THE RIDGE AND VALLEY REGION.
THE SFC/BLYR TEMPS ARE THE TRICK TO THIS FCST - WITH THE SNOW
ACCUMS ALMOST ENTIRELY ELEV /AND SNOWFALL RATE/ DEPENDENT. THE
TIMES OF HEAVY SNOW WILL BE TOUGH TO PINPOINT...AND WILL KEEP IT
BROAD BRUSHED. WILL MAINTAIN THE GOING FCST AS THERE IS NO REASON
TO CHANGE. TEMPS WILL HOVER IN THE LOWER AND MID 30S IN THE
CENTRAL MTS...BUT 30-33 IN THE WRN AND NRN HIGHLANDS. THE ODDITY
OF THIS FCST WILL BE THE RELATIVELY WARM AND DRY AIR THAT GETS
INTO SULLIVAN AND TIOGA COS. ONLY MINOR TWEAKS TO THE SNOW ACCUMS
ARE EXPECTED.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
DEEP TROUGH AND POWERFUL UPPER LOW WILL BE CENTERED OVER THE PA/NY
BORDER MON NIGHT...WITH 500 MB HEIGHTS BELOW 530 FORECAST SOLIDLY BY
THE ECMWF GFS AND NAM. LOW GRADUALLY LIFTS STRAIGHT NORTHWARD AS IT
DEEPENS A BIT FURTHER THROUGH 12Z TUE...THEN BEGINS TO FILL IN ON
TUE UPON ARRIVING IN S CANADA. 987MB SFC LOW ALSO PUSHING NORTHWARD
INTO S NY STATE MON NIGHT WILL FOCUS PRECIP ON ITS COLD SIDE AS 50+
KT COLD CONVEYOR BELT WRAPS AROUND FROM THE NW...WITH LITTLE PRECIP
INDICATED FOR EASTERN HALF OF CWA. SO...ONGOING WINTER WEATHER EVENT
ACROSS WESTERN HALF OF CWA WILL CONTINUE TO BE INTENSE HEADING INTO
MON NIGHT...AND GRADUALLY LESSEN ITS GRIP AS NIGHT PROGRESSES AS
COLD CONVEYOR BELT LIFTS NORTHWARD...RESULTING IN JUST A LIGHTER
SNOW BY 12Z TUE - WHICH WILL LINGER IN THE NORTHERN MTNS POSS INTO
WED.
THE WINTER STORM WARNING/ADVISORY DURATION THROUGH MON NIGHT LOOKS
JUSTIFIED BASED ON QPF FORECASTS/IMPACTS. STORM TOTAL SNOWFALL
OVER MUCH OF THE ALLEGHENIES SHOULD EASILY EXCEED 8 INCHES...WITH
SOME 12-16 INCH AMOUNTS PAINTED IN. SNOWFALL TAPERS OFF FAIRLY
SHARPLY HEADING EAST ACROSS C MTNS...WITH A STRIPE OF 2 TO 5
INCHES IN THE CENTRAL MOUNTAINS - ACCUMULATING MAINLY ON THE
GRASSY SURFACES WITH A LESSER IMPACT ON ROADS. LITTLE ACCUM
EXPECTED IN SUSQ VALLEY...THOUGH SOME SNOW COULD MIX IN ON
OCCASION WITH THE PREDOMINANT PRECIP TYPE OF RAIN - EVEN AS IT
TAPERS TO SHOWERS MON NIGHT INTO TUES.
THE DEEP UPPER TROF LIFTS TO THE NE WED-WED NIGHT...BUT NORTHWEST
FLOW PERSISTS AS ADDITIONAL WEAKER DISTURBANCES ROTATE ACROSS THE
REGION THROUGH THE REMAINDER OF THE WEEK...KEEPING WEATHER SOMEWHAT
UNSETTLED INTO FRI BEFORE A DRIER REGIME MOVES IN. TEMPS LOOK TO BE
BELOW NORMAL FOR MUCH OF THE WEEK.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
STRENGTHENING LOW PRES PASSING JUST EAST OF PA OVERNIGHT WILL
BRING SNOW WITH LOW CIGS/VSBYS AND GUSTY NORTH WINDS ACROSS THE
WESTERN MTNS INTO MONDAY NIGHT. AOO AND UNV ARE ALSO GETTING SOME
SNOW MIXED WITH THE RAIN.
A DRY SLOT IS WORKING INTO SE PA AT THE CURRENT TIME...CAUSING
THE RAIN TO TAPER OFF TO SPOTTY LIGHT OVR THE LWR SUSQ VALLEY.
HOWEVER...MVFR CIGS AND SCT -SHRA SHOULD PERSIST THRU THE NIGHT
AND MONDAY AT IPT/MDT/LNS.
AS THE STORM SYSTEM PASSES JUST TO OUR EAST...EXPECT GUSTY NW
WINDS TO BUFFET THE AREA ON MONDAY...ESP OVR THE LAUREL HIGHLANDS
WHERE BUFKIT SOUNDINGS SUPPORT GUSTS TO NR 30KTS AT JST. THE
COLD...MOIST...UPSLOPING FLOW WILL PRODUCE SNOW AND LOW VSBYS/CIGS
AT BFD/JST. SOMEWHAT BETTER CONDS LIKELY AT AOO/UNV...BUT OCNL
SNOW COULD PRODUCE IFR VSBYS AT TIMES. MOST FAVORABLE CONDS WILL
BE ACROSS THE SUSQ VALLEY...WHERE DRYING...DOWNSLOPING FLOW RESULT
IN ONLY SCT -SHRA.
OUTLOOK...
TUE...LOW CIGS/VSBYS POSS AT BFD IN OCNL SHSN.
WED...NO SIG WX EXPECTED.
THU...RAIN/LOW CIGS POSS.
FRI...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL NOON EDT TUESDAY FOR PAZ004>006-
010>012-017-018-024-033-037-041.
WINTER WEATHER ADVISORY UNTIL 6 AM EDT TUESDAY FOR PAZ019-025-
026-034-035-045.
&&
$$
SYNOPSIS...DANGELO/DEVOIR/LAMBERT
NEAR TERM...DANGELO/DEVOIR/LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1258 AM EDT MON APR 23 2012
.SYNOPSIS...
LOW PRESSURE CENTERED JUST EAST OF NORFOLK VIRGINIA THIS EVENING
GRADUALLY INTENSIFY AS IT PUSHES TO THE NORTH THEN NORTHWEST
OVERNIGHT AND MONDAY...REACHING THE FINGER LAKES REGION OF NEW
YORK STATE LATE MONDAY. COLDER AIR BEING PULLED SOUTH INTO
WESTERN AND CENTRAL PENNSYLVANIA WILL CHANGE THE RAIN OVER TO
HEAVY WET SNOW ACROSS THE NORTHWEST HALF OF THE STATE DURING THE
OVERNIGHT HOURS. THE HEAVIEST SNOW IS EXPECTED ON THE HIGHER
ELEVATIONS OF NORTH CENTRAL AND NORTHWESTERN PENNSYLVANIA...AND
THE LAUREL HIGHLANDS. HEAVY WET ACCUMULATIONS OF SNOW WILL PRODUCE
WIDESPREAD TREE DAMAGE AND LEAD TO POWER OUTAGES. IMPROVING...BUT
STILL UNSETTLED CONDITIONS WILL FOLLOW FOR TUESDAY AND WEDNESDAY
AS THE COLDEST AIR RETREATS NORTHWARD AND A FAST WESTERLY FLOW
ALOFT DEVELOPS.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
EVENT QPF WILL BE LESS DUE TO MORE PROGRESSIVE EVOLUTION OF
NEGATIVE TILT CUTOFF...AND SFC LOW TRACK TO THE CATSKILLS BY 18Z MON.
COLD CONVEYOR BELT SNOWS NOT AS IMPRESSIVE AS A RESULT...AND HAVE
BEGUN THE PROCESS OF CUTTING BACK AMOUNTS OVER THE LAURELS... WEST
CENTRAL MOUNTAINS AND NORTHWEST MOUNTAINS. LOWER END AMOUNTS
REMAIN THE SAME FOR NOW...BUT WILL WATCH EVOLUTION OVERNIGHT AND
BE PREPARED FOR MORE CHANGES IN THE PRE DAWN HOURS.
DUAL POL CORRELATION COEFFICIENT PRODUCT NICELY INDICATES THAT THE
PRECIP HAS CHANGED OVER TO WET SNOW AT THE BEAM HEIGHT OF
2500-3000 MSL JUST TO THE EAST OF THE RDA...WHILE THIS CC PRODUCT
AND SFC OBS INDICATES THAT THE CHANGEOVER HAS REACHED THE GROUND
ACROSS THE NW MTNS. KDUJ AND KBFD CHANGED TO SNOW BETWEEN 00Z AND
01Z...WHILE KFIG AND KJST JUST WENT OVER TO ALL SNOW WITHIN THE PAST
30 MINUTES. SOME WET SNOW FLAKES HAVE BECOME MIXED IN AROUND THE
HAPPY VALLEY AREA...AND A CHANGOVER TO HEAVY WET SNOW SHOULD OCCUR
FROM KAOO TO KUNV BETWEEN 03Z-05Z BASED ON THE 01Z RUC FCST OF MEAN
925-850 MB WET BULB TEMPS DIPPING SLIGHTLY TO JUST -0.5 TO -1C.
MIXED PHASE PRECIP IS NOTED AT ELEVATIONS AS LOW AS 4500 FT MSL TO
THE EAST THROUGH SSE /AT FURTHER DISTANCES AWAY FROM THE RADAR
SITE/...HIGHLIGHTING THE STRONG EAST TO WEST MID LEVEL TEMP GRADIENT
FROM THE CENTRAL MTNS TO THE SUSQ VALLEY.
THE BACK /SWRN EDGE/ EDGE OF THIS CURRENT PRECIP SHIELD WILL
LIKELY EXPAND TO THE SW...AND PIVOT SLOWLY WWD ACROSS THE
COMMONWEALTH OVERNIGHT AND TUESDAY MORNING WITH PRECIP RATES BEING
MAINTAINED OR EVEN INCREASING ACROSS THE CENTRAL MTNS AND
ALLEGHENY PLATEAU...LEADING TO HEAVY WET SNOW WITHIN A FEW
QUASI-SNTRY BANDS OF MDT TO STG FRONTOGENESIS.
NO APPRECIABLE CHANGE WAS MADE TO THE GRIDDED FCST DATABASE WITH
RESPECT TO THE TIMING OF THE RAIN TO SNOW CHANGEOVER...AND
RESULTANT SNOW ACCUMS BY 12Z MONDAY. WILL BE KEEPING A WATCHFUL
EYE THOUGH ON THE HIGH TERRAIN OF SULLIVAN COUNTY /NE OF
KIPT/...SINCE THEY/RE CURRENTLY ONLY IN THE MID 30S WITH WEAK LLVL
COLD ADVECTION CONTINUING. HOWEVER...WARMER AIR SURGING IN ALOFT
FROM THE SSE SHOULD LIMIT ANY CHANGEOVER FOR MUCH OF THE NIGHT TO
JUST A MIX OF WET SNOW AND SLEET AT BEST.
THE RAINFALL IN THE EAST HAS BEEN A STEADY/MODERATELY HEAVY COLD
RAIN FALLING AT A RATE OF GENERALLY 102 TENTHS OF AN INCH PER
HOUR. THE VERY DRY ANTECEDENT CONDITIONS AND EARLY GREEN-UP WILL
ABLE TO EASILY HANDLE THIS RATE...AND TOTAL FCST RAINFALL OF 1-2
INCHES...WITH MINOR TO AT MOST MODERATE RISES ON SMALLER STREAMS
OVER...AND TO THE EAST OF THE SUSQ MAINSTEM.
THE RAIN WILL BE TAPERING OFF IN THE EAST BETWEEN 05Z AND 09Z
MONDAY.
LOW TEMPS OVERNIGHT WILL RANGE FROM THE LOWER 40S IN THE SE
ZONES...TO AROUND 30 ACROSS THE HIGHEST TERRAIN OF THE WEST.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
PERIODS OF MDT TO HEAVY WET SNOW WILL PERSIST ACROSS THE NW MTNS
AND LAUREL HIGHLANDS FOR MUCH OF MONDAY AS THE UPPER LOW TURNS NE
AND LIFTS ACROSS CENTRAL PENN. A MIX OF WET SNOW...AND RAIN IS
STILL EXPECTED IN THE LOWER ELEVS OF THE RIDGE AND VALLEY REGION.
THE SFC/BLYR TEMPS ARE THE TRICK TO THIS FCST - WITH THE SNOW
ACCUMS ALMOST ENTIRELY ELEV /AND SNOWFALL RATE/ DEPENDENT. THE
TIMES OF HEAVY SNOW WILL BE TOUGH TO PINPOINT...AND WILL KEEP IT
BROAD BRUSHED. WILL MAINTAIN THE GOING FCST AS THERE IS NO REASON
TO CHANGE. TEMPS WILL HOVER IN THE LOWER AND MID 30S IN THE
CENTRAL MTS...BUT 30-33 IN THE WRN AND NRN HIGHLANDS. THE ODDITY
OF THIS FCST WILL BE THE RELATIVELY WARM AND DRY AIR THAT GETS
INTO SULLIVAN AND TIOGA COS. ONLY MINOR TWEAKS TO THE SNOW ACCUMS
ARE EXPECTED.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
DEEP TROUGH AND POWERFUL UPPER LOW WILL BE CENTERED OVER THE PA/NY
BORDER MON NIGHT...WITH 500 MB HEIGHTS BELOW 530 FORECAST SOLIDLY BY
THE ECMWF GFS AND NAM. LOW GRADUALLY LIFTS STRAIGHT NORTHWARD AS IT
DEEPENS A BIT FURTHER THROUGH 12Z TUE...THEN BEGINS TO FILL IN ON
TUE UPON ARRIVING IN S CANADA. 987MB SFC LOW ALSO PUSHING NORTHWARD
INTO S NY STATE MON NIGHT WILL FOCUS PRECIP ON ITS COLD SIDE AS 50+
KT COLD CONVEYOR BELT WRAPS AROUND FROM THE NW...WITH LITTLE PRECIP
INDICATED FOR EASTERN HALF OF CWA. SO...ONGOING WINTER WEATHER EVENT
ACROSS WESTERN HALF OF CWA WILL CONTINUE TO BE INTENSE HEADING INTO
MON NIGHT...AND GRADUALLY LESSEN ITS GRIP AS NIGHT PROGRESSES AS
COLD CONVEYOR BELT LIFTS NORTHWARD...RESULTING IN JUST A LIGHTER
SNOW BY 12Z TUE - WHICH WILL LINGER IN THE NORTHERN MTNS POSS INTO
WED.
THE WINTER STORM WARNING/ADVISORY DURATION THROUGH MON NIGHT LOOKS
JUSTIFIED BASED ON QPF FORECASTS/IMPACTS. STORM TOTAL SNOWFALL
OVER MUCH OF THE ALLEGHENIES SHOULD EASILY EXCEED 8 INCHES...WITH
SOME 12-16 INCH AMOUNTS PAINTED IN. SNOWFALL TAPERS OFF FAIRLY
SHARPLY HEADING EAST ACROSS C MTNS...WITH A STRIPE OF 2 TO 5
INCHES IN THE CENTRAL MOUNTAINS - ACCUMULATING MAINLY ON THE
GRASSY SURFACES WITH A LESSER IMPACT ON ROADS. LITTLE ACCUM
EXPECTED IN SUSQ VALLEY...THOUGH SOME SNOW COULD MIX IN ON
OCCASION WITH THE PREDOMINANT PRECIP TYPE OF RAIN - EVEN AS IT
TAPERS TO SHOWERS MON NIGHT INTO TUES.
THE DEEP UPPER TROF LIFTS TO THE NE WED-WED NIGHT...BUT NORTHWEST
FLOW PERSISTS AS ADDITIONAL WEAKER DISTURBANCES ROTATE ACROSS THE
REGION THROUGH THE REMAINDER OF THE WEEK...KEEPING WEATHER SOMEWHAT
UNSETTLED INTO FRI BEFORE A DRIER REGIME MOVES IN. TEMPS LOOK TO BE
BELOW NORMAL FOR MUCH OF THE WEEK.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
STRENGTHENING LOW PRES PASSING JUST EAST OF PA OVERNIGHT WILL
BRING SNOW WITH LOW CIGS/VSBYS AND GUSTY NW WINDS ACROSS THE W
MTNS OVERNIGHT AND MONDAY. AOO AND UNV ARE ALSO LIKELY TO BECOME
IFR AS RAIN CHANGES TO ALL SNOW AFTER MIDNIGHT. A DRY SLOT IS
EXPECTED TO WORK INTO EASTERN PA BTWN 05Z-08Z...CAUSING THE RAIN
TO TAPER OFF OVR THE SUSQ VALLEY. HOWEVER...MVFR CIGS AND SCT
-SHRA SHOULD PERSIST THRU THE NIGHT AT IPT/MDT/LNS.
AS THE STORM SYSTEM PASSES JUST TO OUR EAST...EXPECT GUSTY NW
WINDS TO BUFFET THE AREA ON MONDAY...ESP OVR THE LAUREL HIGHLANDS
WHERE BUFKIT SOUNDINGS SUPPORT GUSTS TO NR 30KTS AT JST. THE
COLD...MOIST...UPSLOPING FLOW WILL PRODUCE SNOW AND LOW VSBYS/CIGS
AT BFD/JST. SOMEWHAT BETTER CONDS LIKELY AT AOO/UNV...BUT OCNL
SNOW COULD PRODUCE IFR VSBYS AT TIMES. MOST FAVORABLE CONDS WILL
BE ACROSS THE SUSQ VALLEY...WHERE DRYING...DOWNSLOPING FLOW RESULT
IN ONLY SCT -SHRA AND MVFR CIGS.
OUTLOOK...
TUE...LOW CIGS/VSBYS POSS AT BFD IN OCNL SHSN.
WED...NO SIG WX EXPECTED.
THU...RAIN/LOW CIGS POSS.
FRI...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL NOON EDT TUESDAY FOR PAZ004>006-
010>012-017-018-024-033-037-041.
WINTER WEATHER ADVISORY UNTIL 6 AM EDT TUESDAY FOR PAZ019-025-
026-034-035-045.
&&
$$
SYNOPSIS...DANGELO/DEVOIR/LAMBERT
NEAR TERM...DANGELO/DEVOIR/LAMBERT
SHORT TERM...DANGELO/LAMBERT
LONG TERM...RXR
AVIATION...FITZGERALD
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1036 PM CDT TUE APR 24 2012
.UPDATE...
WITHIN THE NW FLOW ALOFT...THE BEST CURVATURE AND SHEER IS MOVING
EASTWARD AND AS A RESULT...WE ARE SEEING A PRONOUNCED DECREASE IN
SHOWER COVERAGE OVER MIDDLE TN. WRF...NAM12 AND RUC SOLUTIONS ARE
ALL IN LINE WITH DECREASING THE PRECIP OVERNIGHT.
FOR THE UPDATE WILL REMOVE POPS FOR THE AFT MIDNIGHT PERIOD FOR
MUCH OF WESTERN MIDDLE TN.
REMAINDER OF FCST IN GOOD SHAPE. UPDATE OUT SHORTLY.
&&
.PREV DISCUSSION... /ISSUED 701 PM CDT TUE APR 24 2012/
UPDATE...FOR 00Z AVIATION DISCUSSION.
AVIATION...00Z AVIATION DISCUSSION.
MOISTURE BULK ASSOCIATED WITH UPPER LEVEL SHORTWAVE PASSAGE TO PERSIST
ACROSS MAINLY MID STATE ERN HALF THRU 25/06Z...AND WITH DRY LOW
LEVELS...VSBY SHRA OBSTRUCTIONS MARGINAL AT BEST. LLWS PER
STRENGTHENING WRLY LLJ DYNAMICS 25/05Z-25/14Z. SFC WARM FRONT TO
MOVE ACROSS/BECOME ESTABLISHED E OF AREA BY 25/24Z...ALLOWING FOR
SFC GUSTS TO AROUND 20KTS BNA/CKV BY 25/20Z. ANOTHER UPPER LEVEL
SHORTWAVE DISTURBANCE TO RESULT IN ISO/SCT SHWRS/TSTMS 25/19Z-25/24Z.
PER IMPACTS AT TAF SITES WITH UNCERTAINTY...AND WILL ADDRESS VCTS.
PREV DISCUSSION.../ISSUED 626 PM CDT TUE APR 24 2012/
UPDATE...
MODELS AND THE LATEST RADAR ANALYSIS SUPPORTS THE BETTER MOISTURE
AXIS WILL REMAIN ACROSS THE CUMBERLAND PLATEAU THROUGH THIS
EVENING. STILL RATHER DRY IN THE LOWER LEVELS BUT CONDITIONS
SHOULD MOISTEN UP ENOUGH TO ALLOW THE ACTIVITY TO REACH THE GROUND
SOON.
FOR THE FCST WILL MAKE A QUICK UPDATE AND INCREASE POPS ACROSS THE
PLATEAU AND NORTH CENTRAL ZONES. REMAINDER OF FCST IS IN GOOD
SHAPE. STILL SEEING SOME ADDITIONAL SHOWER ACTIVITY UPSTREAM
ACROSS WESTERN KY.
OTW...FCST LOW TEMPS AND WIND SPEEDS STILL LOOK REASONABLE. UPDATE
OUT SHORTLY.
PREV DISCUSSION... /ISSUED 320 PM CDT TUE APR 24 2012/
DISCUSSION...
RADAR IMAGERY THIS AFTERNOON SHOWS SCATTERED BANDS OF LIGHT RAIN
SHOWERS EXTENDING FROM THE PLATEAU WELL TO THE NORTHWEST ACROSS
MO/IL/IN. THIS ACTIVITY IS IN ASSOCIATION WITH A SOUTHWARD MOVING
SHORTWAVE LOCATED OVER THE OHIO VALLEY...AND AN INCREASING WAA
REGIME DUE TO A STRENGTHENING WESTERLY LLJ. GUIDANCE CONTINUES TO
INDICATE SHOWERS WILL INCREASE IN COVERAGE THROUGH THE AFTERNOON
INTO THE EVENING BEFORE DIMINISHING OVERNIGHT...AND HAVE CHANCE
POPS OVER THE NORTHEAST HALF OF THE CWA TO ACCOUNT FOR THIS
ACTIVITY. RAINFALL AMOUNTS ARE ANTICIPATED TO BE QUITE LIGHT WITH
THIS ACTIVITY...AND NO THUNDERSTORMS ARE EXPECTED AS
THERMODYNAMIC PROFILES ARE TOO DRY/STABLE.
A SIGNIFICANT WARMUP IS IN STORE FOR WEDNESDAY AS LLJ CONTINUES TO
INCREASE UP TO 40-50 KNOTS BY LATE IN THE DAY...WITH HIGHS WELL
INTO THE 70S TO AROUND 80. ATMOSPHERE WILL BECOME QUITE UNSTABLE
ACROSS THE MID STATE TOMORROW AFTERNOON BUT REMAIN CAPPED...SO
ONLY ISOLATED POPS ARE INDICATED FOR NOW WITH BEST CHANCES OVER
NORTHEAST ZONES. BETTER RAIN CHANCES APPEAR ACROSS MIDDLE
TENNESSEE LATE WEDNESDAY NIGHT AND ESPECIALLY THURSDAY AS AN
INTENSE 80 KT H5 JET STREAK PUSHES SOUTHWARD INTO THE OHIO VALLEY
IN THE NW FLOW ALOFT...PUSHING A COLD FRONT TOWARDS THE NORTHERN
CWA. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO FORM OVER
THE MIDWEST WEDNESDAY NIGHT AND QUICKLY MOVE SOUTHEAST
TOWARDS/INTO THE CWA THURSDAY MORNING...WITH ADDITIONAL
DEVELOPMENT ALONG AND AHEAD OF THE FRONTAL BOUNDARY LATER ON
THURSDAY INTO THURSDAY NIGHT. SOME STORMS DURING THIS TIMEFRAME
COULD BE STRONG. CONSIDERABLE MODEL DIFFERENCES REMAIN ON HOW FAR
SOUTH FRONTAL BOUNDARY CAN MAKE IT...WITH NAM KEEPING FRONT WELL
TO OUR NORTH...GFS NEAR THE KY BORDER...AND ECMWF MUCH FURTHER
SOUTH NEAR THE AL BORDER. WHERE FRONT ENDS UP WILL LIKELY DEPEND
ON HOW MUCH CONVECTION DEVELOPS AND CONVECTIVE OUTFLOWS CAN
ASSIST IN DRIVING FRONT SOUTHWARD...AND THIS WILL HAVE A BIG
IMPACT ON TEMPS AND POPS FROM THURSDAY INTO FRIDAY WITH A
POTENTIAL SIGNIFICANT THERMAL GRADIENT FROM SOUTH TO NORTH.
BOUNDARY EXPECTED TO LIFT BACK NORTHWARD ON FRIDAY AS DEEP LOW
PRESSURE DEVELOPS OUT IN THE PLAINS STATES. BRIEF DRY PERIOD IN
THE CARDS FOR FRIDAY NIGHT AND SATURDAY BEFORE LOW PRESSURE OUT
WEST PASSES JUST TO OUR NORTH BRINGING A STRONG COLD FRONT THROUGH
THE MID STATE SATURDAY NIGHT INTO EARLY SUNDAY...WITH ANOTHER
ROUND OF SHOWERS AND STORMS. GLOBAL MODELS CONTINUE TO DEPICT MUCH
COOLER AND DRIER WEATHER BEHIND THE FRONT FOR EARLY NEXT WEEK WITH
TEMPS FALLING BACK BELOW NORMAL FOR SEVERAL DAYS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS BLACKSBURG VA
951 PM EDT TUE APR 24 2012
.SYNOPSIS...
DEEP NORTHEAST U.S. CYCLONE WILL LIFT NORTHWARD INTO CANADA. A
SERIES OF NORTHWEST FLOW DISTURBANCES WILL TRACK ACROSS THE REGION
DURING THE NEXT SEVERAL DAYS...BRINGING A CHANCE OF SHOWERS AND
THUNDERSTORMS TO THE AREA. TEMPERATURES WILL SLOWLY BECOME
MILDER AND MORE SEASONABLE TEMPERATURES DURING THE LATER HALF OF
THE WEEK.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 940 PM EDT TUESDAY...
ISOLATED TO SCATTERED SHOWER HAVE DEVELOPED IN THE WESTERN UPSLOPE
AREAS OF SOUTHEAST WEST VIRGINIA. LOCAL WRF KEPT THIS
PRECIPITATION IN THROUGH 04Z. BY THEN THE DEPARTING LOW SHOULD BE
FAR ENOUGH AWAY AND UPSLOPE SHOULD BE WEAK ENOUGH FOR SHOWERS TO
DISSIPATE.
850MB WINDS WEAKEN TO 10 TO 20 KNOTS BY 06Z/2AM AND GRADUALLY
SHIFT TO THE WEST. SO EXPECT HIGHER RIDGES TO STILL STAY MIXED
OVERNIGHT. WINDS IN THE VALLEYS HAVE ALREADY DECOUPLED AND WILL
REMAIN LIGHT AND VARIABLE OVERNIGHT. HAVE RAISED MINIMUM
TEMPERATURES ALONG THE RIDGES AND KEPT THEM COOLER IN THE VALLEYS.
BAND OF SHOWERS COMING OVER THE TENNESSEE VALLEY WILL MOVE THROUGH
THE EXTREME SOUTHWEST COUNTIES OF THE FORECAST AREA. HAVE ALIGNED
PROBABILITY OF RAIN WITH THE LATEST LOCAL WRF AND HRRR GUIDANCE.
NO CHANGES ARE NEEDED TO THE FREEZE WARNING FOR GREENBRIER AND
BATH COUNTIES. VALLEYS ARE STILL EXPECTED TO DROP INTO THE LOWER
30S.
AS OF 300 PM EDT TUESDAY...
POSTED FREEZE WARNING TONIGHT FOR GREENBRIER AND BATH COUNTIES WHERE
WIDESPREAD OVERNIGHT LOW TEMPERATURES DROP INTO THE UPPER 20S AND
LOWER 30S.
A NORTHWEST FLOW SHORTWAVE WILL TRACK FROM THE UPPER MIDWEST INTO
THE EASTERN TENNESSEE VALLEY THIS EVENING INTO TONIGHT. ALLOWED
FOR ISOLATED TO SCATTERED POPS OF CONVECTION TONIGHT WITH
STEEP LAPSE RATES PROGGED WITH SHORTWAVE. ADDED THE MENTION OF AN
ISOLATED THUNDERSTORM THIS EVENING ACROSS NORTHERN NORTH CAROLINA.
PLAYED LOW TEMPERATURES CLOSE TO ADJMET WITH READINGS FROM THE UPPER
20S IN THE NORTHWEST MOUNTAINS TO AROUND 40 DEGREES IN SOUTHSIDE.
ANOTHER SHORTWAVE WILL MOVE FROM THE OHIO VALLEY INTO THE MOUNTAINS
WEDNESDAY AFTERNOON...ALONG A WARM FRONT. WITH LIMITED MOISTURE
EXPECT A FEW SHOWERS ACROSS THE WEST. THE BEST CHANCE WILL OCCUR
ACROSS THE FAR SW VA/NW NC CWA. PLAYED HIGH TEMPERATURES FROM THE
UPPER 50S IN THE MOUNTAINS TO THE LOWER 70S IN THE SOUTHEAST.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 330 PM EDT TUESDAY...
UPPER LEVEL FLOW WILL BECOME ZONAL FOR THE LATER HALF OF THE WEEK.
SURFACE WARM FRONT WILL DEVELOP AND LIFT NORTH FROM THE LOWER MS/TN
VALLEYS. THIS FRONT IS EXPECTED TO SLOWLY GAIN LATITUDE...BUT
NEVER REALLY CLEAR THE FORECAST AREA...BECOMING ALIGNED WEST TO
EAST FROM THE MIDWEST CONUS INTO THE MID ATLANTIC REGION. UPPER
LEVEL DISTURBANCES...ILL TIMED BY MODELS...TO RIPPLE EAST ALONG
THE FRONT FROM WEDNESDAY NIGHT INTO THE WEEKEND. CHALLENGE WILL BE
TIMING OF THE WAVES WITHIN THE FAST ZONAL FLOW.
WITH FRONT BISECTING THE CWA...VERY JUICY AIR MASS SOUTH OF THE
FRONT WILL FUEL TSTM DEVELOPMENT ALONG AND JUST NORTH OF FRONTAL
BOUNDARY. THIS WILL PUT OUR FCST AREA ON THE RECEIVING END FOR ANY
UPSTREAM MCS THAT MAY DEVELOP OVER THE MIDWEST AND OHIO VALLEY REGION.
THE STORM PREDICTION CENTER HAS PORTION OF THE AREA HIGHLIGHTED
FOR ISOLATED SVR THURSDAY. THE LIMITING FACTOR WILL BE CLOUD COVER/LACK
OF SURFACE HEATING...BUT ENHANCEMENT MAY COME FROM THE STRONG
WESTERLY FLOW OF MOIST/UNSTABLE AIR FROM THE OHIO AND TN VALLEYS.
DEPENDING ON WHERE THURSDAYS TSTM ACTIVITY TAKES PLACE...FRONT MAY GET
SHOVED JUST FAR ENOUGH SOUTH TO KEEP US MAINLY DRY FRIDAY (ECMWF
SOLUTION)...OR IT MAY NOT (GFS SOLUTION) WITH OPPORTUNITY FOR
MORE SHOWERS AND STORMS FRIDAY.
TEMPS SHOULD CLIMB BACK TO AT OR ABOVE NORMAL. AM CONCERNED THAT
HIGHS THURSDAY COULD BE COOLER IF THE PRECIP AND CLOUD COVER IS
MORE WIDESPREAD. THEREFORE...WENT COOLER THAN MOS...BUT STILL 5 DEGREES
ABOVE THE CLIMATOLOGICAL NORM.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 400 PM EDT TUESDAY...
FRONT TO BISECT THE AREA THROUGH THE WEEKEND WITH ADDITIONAL
THREAT FOR SHOWERS/STORMS. MODELS ARE IN SOMEWHAT OF AN AGREEMENT
THAT A FINAL UPPER LEVEL WAVE OF ENERGY WILL PASS THROUGH THE
FCST AREA LATE SATURDAY OR SUNDAY...PUSHING THE BOUNDARY WELL
SOUTH OF THE FCST AREA BY MONDAY. AS SUCH...NO MENTION OF POPS
POST SUNDAY.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
AS OF 715 PM EDT TUESDAY...
BREEZY AND GUSTY NORTHWEST WINDS WILL RELAX UNDER 8KTS THIS EVENING.
SHORT WAVE TRACKING OVER THE AREA THIS EVENING WILL KEEP PUFFY VFR
CUMULUS CLOUDS IN THE REGION. SUBSIDENCE AND LOSE OF HEATING WILL
HAVE THESE CLOUDS DISSIPATING. AS THE SHORT WAVE TRACKS EAST OF THE
AREA...VFR STRATUS DECK EXPECTED TO MOVE INTO THE SOUTHWEST PORTION
OF RNK CWA.
THE NEXT WEATHER MAKER WILL TRACK ACROSS THE OHIO VALLEY DURING THE
DAY WEDNESDAY. MOSTLY CLEAR SKIES EXPECTED UNTIL LATE IN THE
AFTERNOON WHEN A POSSIBLE MESOSCALE COMPLEX (MCS) COULD ENTER THE
AREA (GFS). THE NAM IS SLOWER AND FARTHER TO THE NORTH WITH THE MCS
TRACK. IN THE WAKE OF THE MCS...SUBSIDENCE WILL BRING A BRIEF DRY
PERIOD TO THE REGION. ANOTHER AREA OF DISTURBED WEATHER WILL THEN
ENTER THE REGION THURSDAY NIGHT/FRIDAY...ANOTHER ONE SATURDAY
SATURDAY NIGHT.
CONFIDENCE IS VERY LOW WITH BOTH SPACIAL AND TEMPORAL RESPECTS FOR
SYSTEMS BEYOND THE TAF PERIOD.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...FREEZE WARNING UNTIL 8 AM EDT WEDNESDAY FOR VAZ020.
NC...NONE.
WV...FREEZE WARNING UNTIL 8 AM EDT WEDNESDAY FOR WVZ045.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/KK
SHORT TERM...PM
LONG TERM...PM
AVIATION...RCS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1040 PM CDT TUE APR 24 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW SURFACE LOW
PRESSURE SITUATED OVER SE SASKATCHEWAN EARLY THIS AFTERNOON...AND
WARM FRONT STRETCHING SOUTHEAST OVER THE NORTHERN PLAINS. WISCONSIN
STILL RESIDES WITHIN CYCLONIC AND NORTHERLY FLOW AROUND A DEEP LOW
PRESSURE SYSTEM OVER QUEBEC. MID-LEVEL MOISTURE...DIURNAL
HEATING...AND DEEP MIXING HAS CONTRIBUTED TO A WIDESPREAD CU FIELD
OVER NE WISCONSIN. TEMPS HAVE WARMED QUICKLY TODAY INTO THE 60S
EXCEPT NEAR LAKE MICHIGAN AND OVER FAR NORTHERN WISCONSIN. AS LOW
PRESSURE MOVE SE FROM THE NORTHERN PLAINS INTO ILLINOIS TONIGHT INTO
WEDNESDAY...PRECIP CHANCES ARE THE MAIN FORECAST CONCERN.
TONIGHT...LOW PRESSURE OVER SE SASKATCHEWAN WILL SLIDE SE ALONG A
BAROCLINIC ZONE STRETCHING FROM THE NORTHERN PLAINS TO THE OHIO
VALLEY. FGEN NORTH OF THIS BAROCLINIC ZONE OVER SASKATCHEWAN AND
MANITOBA WILL SLIDE SE AS WELL INTO THE NORTHERN MISSISSIPPI VALLEY
BY 12Z WEDNESDAY. THOUGH CLOUDS WILL BE INCREASING AHEAD OF THE
FGEN BAND LATE TONIGHT...AND LOWERING AS WELL...AM COUNTING ON DRY
SE FLOW IN THE LOW LEVELS TO KEEP PRECIP WEST OF THE REGION
TONIGHT. INHERITED LOW CHANCE POPS OVER NORTH-CENTRAL
WISCONSIN...AND WILL KEEP THEM JUST IN CASE SHOWERS BECOME A TAD
MORE AMBITIOUS THAN THE CURRENT THINKING. TEMPERATURES RANGING FROM
THE MID 30S NORTH TO LOW 40S SOUTH.
WEDNESDAY...MODELS HAVE COME INTO BETTER AGREEMENT TRACKING THE
SURFACE LOW PRESSURE FROM SW MINNESOTA TO NORTHWEST ILLINOIS BY 00Z
THU. THE TIGHTER BAROCLINIC ZONE UPSTREAM WILL SHIFT EAST INTO SW
WISCONSIN...WITH MID-LEVEL FGEN AND UPPER DIVERGENCE INCREASING
ACROSS THE AREA DURING THE MORNING...THEN PASSING ACROSS THE AREA
DURING THE AFTERNOON. THIS SHOULD LEAD TO A PRETTY GOOD SWATH OF
SHOWERS THROUGH THE DAY OVER CENTRAL WISCONSIN WHERE THE BEST
FORCING WILL RESIDE...THOUGH ALL AREAS STAND TO GET SOME RAIN. WILL
INCREASE POPS AND QPF. CLOUDS...RAIN...AND SE FLOW WILL LEAD TO A
CONSIDERABLY COOLER DAY. HAVE SIDED WITH THE COOLER GUIDANCE
WHICH PLACES HIGHS IN THE MID 50S NORTH TO NEAR 60 SOUTH.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY...MAIN FCST
CONCERNS ARE PCPN TRENDS WEDS NGT...POTENTIAL FOR MORE HARD
FREEZES LATE IN THE WEEK...THEN WHETHER OR NOT TO KEEP SMALL
POPS IN THE FCST FOR THE WEEKEND.
ISENT LIFT AND ASSOCIATED SHOWERS WILL BE ONGOING EARLY WEDS
EVENING...IN ADVANCE OF A COLD FRONT. IN ADDITION...A SHORT-WAVE
TROF IS EXPECTED TO BRUSH PAST NE WI DURING THE NIGHT. HAVE RAISED
POPS TO LIKELY OVER FAR NE WI FOR THE EVG HOURS...THEN CONTINUED
THE TREND OF DECREASING SHOWERS FOR THE OVERNIGHT PERIOD.
CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF
THE COLD FRONT ON THURSDAY AND FRIDAY...BRINGING DRY AND COOLER
CONDITIONS. SUB-FREEZING TEMPERATURES APPEAR LIKELY OVER NEARLY ALL
OF THE CWA ON THURSDAY NIGHT. LOWERED MIN TEMPS OVER THE ENTIRE
AREA...WITH READINGS AS LOW AS 20 IN THE TYPICAL COLD SPOTS IN NC
WI. WOULD NOT BE SURPRISED IF A FEW LOCATIONS GET INTO THE TEENS.
MODELS HAVE TRENDED FARTHER SOUTH WITH LOW PRESSURE MOVG THROUGH
THE UPPER MIDWEST OVER THE WEEKEND...AND KEEP C/NE WI ENTRENCHED
IN DRY AIR FEEDING OUT OF THE MASSIVE CANADIAN HIGH. HAVE REMOVED
ALL PCPN FROM THE WEEKEND FCST...AND DON`T BRING ANY RAIN BACK
INTO THE FCST UNTIL THE CANADIAN HIGH SHIFTS EAST MONDAY NIGHT
INTO TUESDAY. THIS WILL MEAN THAT THERE WILL BE CONTINUED
POTENTIAL FOR FREEZING NIGHTTIME TEMPERATURES DURING THIS
PERIOD...SO THOSE WITH AGRICULTURAL CONCERNS SHOULD STAY TUNED TO
THE LATEST FCSTS.
&&
.AVIATION...MID LEVEL VFR CIGS WILL INCREASE FROM THE NORTH
OVERNIGHT. CIGS WILL LOWER TO AROUND 4000 TO 5000 FT LEVELS ON
WEDNESDAY AS RAIN SPREADS OVER THE AREA...WITH SCATTERED MVFR CIGS
LATER WEDNESDAY AFTERNOON INTO EVENING.
TDH
&&
.FIRE WEATHER...ALTHOUGH SHOWER ACTIVITY WILL RESULT IN A BRIEF
REPRIEVE FROM THE LOW HUMIDITY ON WEDNESDAY...A LARGE CANADIAN
HIGH PRESSURE SYSTEM WILL RETURN TO THE REGION ON THURSDAY...
AND REMAIN OVER THE AREA THROUGH ABOUT NEXT MONDAY. WITH VERY DRY
AIR ENTRENCHED OVER THE REGION...HUMIDITY READINGS WILL LIKELY
DROP TO NEAR CRITICAL LEVELS AGAIN FOR THE END OF THE WORK WEEK
AND THE WEEKEND.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
525 PM CDT MON APR 23 2012
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY.
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE STRETCHING FROM THE SOUTHERN GREAT PLAINS...ACROSS THE
WESTERN GREAT LAKES TO WESTERN HUDSON BAY EARLY THIS AFTERNOON.
VERY DRY AIR JUST OFF THE SURFACE PER 12Z GRB RAOB HAS LED TO
DEWPOINTS PLUMMETING INTO THE SINGLE DIGITS OVER SOME OF THE SANDY
SOIL AREAS OF FAR NE AND NORTH-CENTRAL WISCONSIN. UPSTREAM...PLENTY
OF MID AND HIGH CLOUDS OVER NORTHERN MINNESOTA INTO MANITOBA WHERE
ISENTROPIC ASCENT IS OCCURRING ON THE 295-300K SURFACES. MAIN
FORECAST CONCERNS INCLUDE CLOUD COVERAGE AND PRECIP CHANCES AS THE
UPSTREAM ISENTROPIC ASCENT MOVES INTO WISCONSIN TONIGHT INTO TUESDAY.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST INTO SOUTHEAST ONTARIO
WHILE A WEAK AREA OF HIGH PRESSURE WILL REMAINED ANCHORED FROM
HUDSON BAY...ACROSS THE WESTERN GREAT LAKES...TO THE GULF COAST.
MOISTURE WILL CONTINUE TO SPILL OVER TOP OF THE RIDGE CENTERED OVER
THE ROCKIES AND FILTER ACROSS THE STATE FROM WEST TO EAST TONIGHT.
WILL HAVE INCREASING CLOUDS AS A RESULT...BUT NOT ENOUGH TO GO MORE
THAN PARTLY CLOUDY WEST TO MOSTLY CLEAR IN THE EAST. LOWS ARE
TRICKY DUE TO THE DRY AIRMASS IN PLACE YET WILL HAVE INCREASING
CLOUDS. WILL GO WITH LOWS RANGING FROM THE UPPER 20S NORTH TO UPPER
30S SOUTHEAST.
TUESDAY...850MB WARM FRONT WILL MOVE INTO THE NORTHERN MISSISSIPPI
VALLEY WHILE MID-LEVEL MOISTURE FROM THE LAKE WINNIPEG REGION WILL
SLIDE SOUTHEAST ACROSS THE AREA DURING THE MORNING. AS DIURNAL
HEATING OCCURS...WILL SEE CAPES BETWEEN 50-100 J/KG DEVELOP THAT
SHOULD HELP FILL IN WHATEVER HOLES THERE ARE IN THE CLOUD DECK.
WOULDNT BE SURPRISED TO SEE MOSTLY CLOUDY CONDITIONS DEVELOP BY
MIDDAY...BUT WILL GO WITH PARTLY SUNNY WORDING INSTEAD TO BLEND WITH
SURROUNDING OFFICES. BOTH THE NAM AND GFS TRIGGER LIGHT QPF OVER EASTERN
WISCONSIN. THINK THIS IS A TOO PESSIMISTIC...AS ITS TOUGH TO FIND A
TRIGGER...AND INSTABILITY IS PRETTY MEAGER. SO WILL STAY WITH A DRY
FORECAST. DRIER AIR DOES RETURN FROM THE NORTH DURING THE
AFTERNOON...SO SHOULD SEE AT LEAST PARTIAL CLEARING ARRIVE. HIGHS
ROUGHLY ABOUT 4 DEGREES WARMER THAN TODAY...FROM THE UPPER 50S NORTH
TO MIDDLE 60S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...MAIN FCST CONCERNS
ARE PCPN TRENDS FOR THE MIDWEEK PERIOD AND NEXT WEEKEND.
LOW PRESSURE OVER THE NORTHERN PLAINS ON TUESDAY EVG IS EXPECTED TO
SHIFT SE TOWARD ILLINOIS ON WEDNESDAY. A FAIRLY STG BAROCLINIC
ZONE WILL SET UP OVER THE REGION...WITH ISENT LIFT DEVELOPING LATE
TUESDAY NIGHT INTO WEDNESDAY AS LLVL FLOW BECOMES SW AHEAD OF AN
APPROACHING COLD FRONT. IN ADDITION...SOME SHORT-WAVE ENERGY AND THE
RRQ OF AN UPPER JET STREAK WILL BE PULLING THROUGH THE AREA. HAVE
KEPT CHC POPS FOR OUR SW COUNTIES AFTER MIDNIGHT TUESDAY NIGHT...
THEN ADJUSTED PCPN TRENDS AS PCPN SPREADS NORTHEAST ON WEDNESDAY.
RAISED POPS INTO THE LIKELY CATEGORY OVER ABOUT THE SW TWO-THIRDS
OF THE CWA ON WEDS. ALSO ADDED A CHC OF TSTMS ON WEDS AFTERNOON AS
MODELS SHOW A BAND OF INSTABILITY DEVELOPING IN ADVANCE OF THE
COLD FRONT. THIS FRONT SHOULD GENERATE SOME SHOWERS INTO WEDS
NIGHT...ESPECIALLY DURING THE EVG.
CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF
THE COLD FRONT ON THURSDAY AND FRIDAY...BRINGING DRY AND COOLER
CONDITIONS. SUB-FREEZING TEMPERATURES WILL ONCE AGAIN BE POSSIBLE ON
THURSDAY NIGHT.
A BATTLE OF THE AIR MASSES IS SETTING UP FOR THE WEEKEND...WITH
DRY CANADIAN HIGH PRESSURE STILL RIDGED TO OUR NORTH...AND LOW
PRESSURE AND ABUNDANT MOISTURE TRACKING THROUGH THE UPPER MIDWEST.
AS THE LOW PASSES TO OUR SOUTH...EXPECT NE WINDS TO INCREASE...
WHICH SHOULD REINFORCE THE DRY AIR OVER AT LEAST NORTHERN WI.
WILL CARRY SOME LOW CHANCE POPS OVER MAINLY OUR SOUTHERN COUNTIES
SATURDAY INTO SUNDAY...BUT WOULD NOT BE SURPRISED IF THE DRY AIR
EVENTUALLY WINS THIS BATTLE.
THE CANADIAN HIGH IS EXPECTED TO SAG SOUTH OVER THE REGION AGAIN
LATER SUNDAY INTO MONDAY...WITH ASSOCIATED DRY CONDITIONS.
&&
.AVIATION...A VFR CIG WILL SPREAD OVER THE AREA LATE TONIGHT AND
CONTINUE INTO TUESDAY. A DEEP LOW PRESSURE SYSTEM OVER THE EASTERN
SEABOARD REGION WILL CONTINUE TO PRODUCE GUSTY NORTH WINDS THIS
EVENING OVER EASTERN WISCONSIN. WINDS WILL DIMINISH OVERNIGHT INTO
TUESDAY MORNING...HOWEVER GUSTY NORTHWEST WINDS MAY OCCUR AGAIN
TUESDAY AFTERNOON.
TDH
&&
.MARINE...A TIGHTENING PRESSURE GRADIENT WILL LEAD TO NEAR SMALL
CRAFT ADVISORY WIND GUSTS OVER THE NEARSHORE WATERS THIS EVENING.
THE AREA AROUND DEATHS DOOR WILL BE THE MOST PRONE FOR THESE HIGHER
GUSTS.
&&
.FIRE WEATHER...DRY AIR JUST OFF THE SURFACE PER 12Z GRB RAOB HAS
LED TO RH/S CRASHING TO THE 10-15 PCT RANGE OVER MUCH OF FAR
NORTHEAST AND NORTH-CENTRAL WISCONSIN. WITH WIND GUSTS UP TO 20
KTS...WILL CONTINUE TO MENTION AN ELEVATED FIRE DANGER IN THE HWO.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
258 PM CDT MON APR 23 2012
.SHORT TERM...TONIGHT AND TUESDAY.
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH
PRESSURE STRETCHING FROM THE SOUTHERN GREAT PLAINS...ACROSS THE
WESTERN GREAT LAKES TO WESTERN HUDSON BAY EARLY THIS AFTERNOON.
VERY DRY AIR JUST OFF THE SURFACE PER 12Z GRB RAOB HAS LED TO
DEWPOINTS PLUMMETING INTO THE SINGLE DIGITS OVER SOME OF THE SANDY
SOIL AREAS OF FAR NE AND NORTH-CENTRAL WISCONSIN. UPSTREAM...PLENTY
OF MID AND HIGH CLOUDS OVER NORTHERN MINNESOTA INTO MANITOBA WHERE
ISENTROPIC ASCENT IS OCCURRING ON THE 295-300K SURFACES. MAIN
FORECAST CONCERNS INCLUDE CLOUD COVERAGE AND PRECIP CHANCES AS THE
UPSTREAM ISENTROPIC ASCENT MOVES INTO WISCONSIN TONIGHT INTO TUESDAY.
TONIGHT...LOW PRESSURE WILL MOVE NORTHEAST INTO SOUTHEAST ONTARIO
WHILE A WEAK AREA OF HIGH PRESSURE WILL REMAINED ANCHORED FROM
HUDSON BAY...ACROSS THE WESTERN GREAT LAKES...TO THE GULF COAST.
MOISTURE WILL CONTINUE TO SPILL OVER TOP OF THE RIDGE CENTERED OVER
THE ROCKIES AND FILTER ACROSS THE STATE FROM WEST TO EAST TONIGHT.
WILL HAVE INCREASING CLOUDS AS A RESULT...BUT NOT ENOUGH TO GO MORE
THAN PARTLY CLOUDY WEST TO MOSTLY CLEAR IN THE EAST. LOWS ARE
TRICKY DUE TO THE DRY AIRMASS IN PLACE YET WILL HAVE INCREASING
CLOUDS. WILL GO WITH LOWS RANGING FROM THE UPPER 20S NORTH TO UPPER
30S SOUTHEAST.
TUESDAY...850MB WARM FRONT WILL MOVE INTO THE NORTHERN MISSISSIPPI
VALLEY WHILE MID-LEVEL MOISTURE FROM THE LAKE WINNIPEG REGION WILL
SLIDE SOUTHEAST ACROSS THE AREA DURING THE MORNING. AS DIURNAL
HEATING OCCURS...WILL SEE CAPES BETWEEN 50-100 J/KG DEVELOP THAT
SHOULD HELP FILL IN WHATEVER HOLES THERE ARE IN THE CLOUD DECK.
WOULDNT BE SURPRISED TO SEE MOSTLY CLOUDY CONDITIONS DEVELOP BY
MIDDAY...BUT WILL GO WITH PARTLY SUNNY WORDING INSTEAD TO BLEND WITH
SURROUNDING OFFICES. BOTH THE NAM AND GFS TRIGGER LIGHT QPF OVER EASTERN
WISCONSIN. THINK THIS IS A TOO PESSIMISTIC...AS ITS TOUGH TO FIND A
TRIGGER...AND INSTABILITY IS PRETTY MEAGER. SO WILL STAY WITH A DRY
FORECAST. DRIER AIR DOES RETURN FROM THE NORTH DURING THE
AFTERNOON...SO SHOULD SEE AT LEAST PARTIAL CLEARING ARRIVE. HIGHS
ROUGHLY ABOUT 4 DEGREES WARMER THAN TODAY...FROM THE UPPER 50S NORTH
TO MIDDLE 60S SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH NEXT MONDAY...MAIN FCST CONCERNS
ARE PCPN TRENDS FOR THE MIDWEEK PERIOD AND NEXT WEEKEND.
LOW PRESSURE OVER THE NORTHERN PLAINS ON TUESDAY EVG IS EXPECTED TO
SHIFT SE TOWARD ILLINOIS ON WEDNESDAY. A FAIRLY STG BAROCLINIC
ZONE WILL SET UP OVER THE REGION...WITH ISENT LIFT DEVELOPING LATE
TUESDAY NIGHT INTO WEDNESDAY AS LLVL FLOW BECOMES SW AHEAD OF AN
APPROACHING COLD FRONT. IN ADDITION...SOME SHORT-WAVE ENERGY AND THE
RRQ OF AN UPPER JET STREAK WILL BE PULLING THROUGH THE AREA. HAVE
KEPT CHC POPS FOR OUR SW COUNTIES AFTER MIDNIGHT TUESDAY NIGHT...
THEN ADJUSTED PCPN TRENDS AS PCPN SPREADS NORTHEAST ON WEDNESDAY.
RAISED POPS INTO THE LIKELY CATEGORY OVER ABOUT THE SW TWO-THIRDS
OF THE CWA ON WEDS. ALSO ADDED A CHC OF TSTMS ON WEDS AFTERNOON AS
MODELS SHOW A BAND OF INSTABILITY DEVELOPING IN ADVANCE OF THE
COLD FRONT. THIS FRONT SHOULD GENERATE SOME SHOWERS INTO WEDS
NIGHT...ESPECIALLY DURING THE EVG.
CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION IN THE WAKE OF
THE COLD FRONT ON THURSDAY AND FRIDAY...BRINGING DRY AND COOLER
CONDITIONS. SUB-FREEZING TEMPERATURES WILL ONCE AGAIN BE POSSIBLE ON
THURSDAY NIGHT.
A BATTLE OF THE AIR MASSES IS SETTING UP FOR THE WEEKEND...WITH
DRY CANADIAN HIGH PRESSURE STILL RIDGED TO OUR NORTH...AND LOW
PRESSURE AND ABUNDANT MOISTURE TRACKING THROUGH THE UPPER MIDWEST.
AS THE LOW PASSES TO OUR SOUTH...EXPECT NE WINDS TO INCREASE...
WHICH SHOULD REINFORCE THE DRY AIR OVER AT LEAST NORTHERN WI.
WILL CARRY SOME LOW CHANCE POPS OVER MAINLY OUR SOUTHERN COUNTIES
SATURDAY INTO SUNDAY...BUT WOULD NOT BE SURPRISED IF THE DRY AIR
EVENTUALLY WINS THIS BATTLE.
THE CANADIAN HIGH IS EXPECTED TO SAG SOUTH OVER THE REGION AGAIN
LATER SUNDAY INTO MONDAY...WITH ASSOCIATED DRY CONDITIONS.
&&
.AVIATION...VFR CONDITIONS TODAY THOUGH WILL HAVE INCREASING AND
GUSTY NORTH WINDS THROUGH EARLY THIS EVENING. BKN MID AND HIGH
CLOUDS WILL DRIFT ACROSS THE TAF SITES FROM THE NORTH TONIGHT...AND
LOWER TO ABOUT 5-7KFT TUESDAY MORNING. PARTIAL CLEARING IS
ANTICIPATED BY LATE TUESDAY AFTERNOON.
MPC
&&
.MARINE...A TIGHTENING PRESSURE GRADIENT WILL LEAD TO NEAR SMALL
CRAFT ADVISORY WIND GUSTS OVER THE NEARSHORE WATERS THIS EVENING.
THE AREA AROUND DEATHS DOOR WILL BE THE MOST PRONE FOR THESE HIGHER
GUSTS.
&&
.FIRE WEATHER...DRY AIR JUST OFF THE SURFACE PER 12Z GRB RAOB HAS
LED TO RH/S CRASHING TO THE 10-15 PCT RANGE OVER MUCH OF FAR
NORTHEAST AND NORTH-CENTRAL WISCONSIN. WITH WIND GUSTS UP TO 20
KTS...WILL CONTINUE TO MENTION AN ELEVATED FIRE DANGER IN THE HWO.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
346 AM CDT MON APR 23 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT
346 AM CDT MON APR 23 2012
MAIN FORECAST CONCERNS THIS PACKAGE...WARMING TEMPERATURES TODAY/
TUE...PRECIPITATION CHANCES FROM TUE NIGHT THROUGH WED NIGHT.
06Z SURFACE ANALYSIS HAD A BROAD AREA OF HIGH PRESSURE OVER MUCH
OF THE CENTRAL CONUS...CENTERED OVER EASTERN NEB. WITH THE HIGH
RATHER SPRAWLING WITH WEAK GRADIENTS OVER THE REGION WINDS WERE ON
THE LIGHT SIDE. FOG-PRODUCT IMAGERY INDICATED A COUPLE SMALLER
AREAS OF ALTO-CUMULUS DRIFTING SOUTHEAST ACROSS MN/WI. OTHERWISE
SKIES WERE CLEAR OVER THE UPPER MIDWEST EARLY THIS MORNING WITH
TEMPERATURES NEAR LATE APRIL NORMALS.
23.00Z MODELS HAVE INITIALIZED WITHOUT MAJOR ERRORS AND OFFER QUITE
SIMILAR SOLUTIONS FOR TODAY THRU WED NIGHT. SOME DIFFERENCES WITH
TIMING/AMOUNT OF PRECIP WITH THE NORTHWEST FLOW SYSTEM TO MOVE
ACROSS THE AREA LATER TUE NIGHT THRU WED EVENING...BUT THIS TO BE
EXPECTED WITH THE SHORTWAVE OF INTEREST STILL ON THE WEST SIDE OF
THE RIDGE AXIS. DPROG/DT OF 500MB HGTS AT 23.00Z SHOWED MODEL RUNS
OF 21.00Z AND 22.00Z VERIFIED WELL ACROSS NOAM/EASTERN PAC. MODELS
MARCHING TOWARD A TIGHTER CONSENSUS TODAY THRU WED NIGHT AS ONE
UPPER LOW LIFTS NORTH THRU THE EASTERN CONUS/CAN AND THE NEXT
TROUGHING MOVES ONTO THE WEST COAST. TREND TENDS TO FAVOR SLOWER OF
EARLIER RUNS WITH THE EASTERN NOAM TROUGH AND A COMPROMISE WITH THE
TROUGHING TO MOVE ONTO THE WEST COAST. CHECK OF OBS VS. MODEL DATA
AT 06Z SHOWED MODELS GOOD WITH THE HIGH OVER THE CENTRAL CONUS AND
THE STRONG LOW MOVING UP THE EAST COAST. PER WV IMAGERY ALL LOOKED
VERY REASONABLE WITH THE SHORTWAVE DETAILS ACROSS NOAM/EASTERN PAC.
NO CLEAR MODEL FAVORITE THIS CYCLE. WITH THE TREND TOWARD A
COMPROMISE IN THE EAST/WESTERN TROUGHS...WILL FAVOR A COMPROMISE
WITH THE SHORTWAVE TO TOP THE RIDGE AND IMPACT THE AREA TUE NIGHT
INTO WED NIGHT. OVERALL SHORT-TERM FCST CONFIDENCE AVERAGE TO GOOD
THIS CYCLE.
IN THE SHORT TERM...QUIET WEATHER TODAY THRU TUE AS A PORTION OF THE
SFC RIDGE AXIS REMAINS OVER THE REGION...SANDWICHED BETWEEN THE LOW
LIFTING FROM NJ TO WESTERN QUEBEC AND LOW PRESSURE DEVELOPING IN
THE NORTHERN PLAINS. SFC GRADIENT WINDS WILL REMAIN LIGHT...BUT
MODEL SOUNDINGS INDICATE RATHER DEEP MIXING TODAY UNDER PARTLY
CLOUDY TO SUNNY SKIES AND 850MB TEMPS A COUPLE DEGREES EITHER SIDE
OF 0C. 925-850MB WINDS IN THE 15-20KT RANGE TODAY SO SOME INCREASE
OF WINDS/GUSTINESS EXPECTED FOR THE AFTERNOON. MODELS WITH A RATHER
CONSISTENT SIGNAL FOR SOME MOISTURE AROUND 700MB AND WEAK VERTICAL
MOTION TO SPREAD ACROSS THE AREA TONIGHT THEN LINGER INTO TUE.
EVEN WITH THE HIGH OVER THE REGION...PARTLY TO MOSTLY CLOUDY SKIES
EXPECTED TONIGHT. 925-850MB RIDGE AXIS IS CLOSER/OVER THE AREA
TUE...FOR THE WINDS TO REMAIN LIGHT. TIGHTER MODEL CONSENSUS
BEGINNING TO FOCUS THE RAIN CHANCES TUE NIGHT INTO WED NIGHT.
INCREASE OF MOISTURE/LIFT INTO THE AREA WITH THE HGT FALLS AND LOWER
LEVEL THERMO-DYNAMIC FORCING AHEAD OF THE SHORTWAVE AND NORTHERN
PLAINS LOW ARRIVES LATER TUE NIGHT. REMOVED -SHRA/TSRA CHANCE
FROM TUE EVENING. STRONGEST OF LIFT/DEEPEST OF MOISTURE TRANSLATES
ACROSS THE AREA WED...HOWEVER BULK OF MOISTURE/LIFT IS ABOVE 700MB.
THIS MAY BE WHY MODELS ARE SOMEWHAT INCONSISTENT PUTTING PRECIP ON
THE GROUND AS THIS WAVE AND THE FORCING PASS. DID RAISE SHRA/TSRA
CHANCES ON WED TO AROUND 50 PERCENT FOR NOW. NOT CONVINCED OF TSRA
CENTERED ON WED BUT WITH MODELS SHOWING AT LEAST MOIST ADIABATIC
LAPSE RATES ABOVE 700MB AND AROUND 1000 J/KG OF MU CAPE IN THE
INFLOW AIRMASS...LEFT CHANCES OF TSRA IN GRIDS FOR NOW. IMPROVING
MODEL CONSENSUS HAS THE WAVE/FORCING/LIFT PASSING WED NIGHT WITH
SUBSIDENCE/DRYING OF THE COLUMN SPREADING SOUTHEAST ACROSS THE FCST
AREA LATER IN THE EVENING AND OVERNIGHT. CONTINUED A 20-30 PERCENT
CHANCE OF SHRA OVER THE SOUTHEAST HALF OF THE FCST AREA WED EVENING
AND REMOVED RAIN CHANCES FROM LATER WED NIGHT.
TRENDED TOWARD A BLEND OF THE NUMERICAL GUIDANCE HIGHS/LOWS FOR
TODAY...TONIGHT...TUE NIGHT. TEMPERED THE TUE WARM-UP A BIT WITH
POTENTIAL FOR SOME MID CLOUDS AND STRONGER OF 925-850MB WARMING
REMAINING WEST OF THE AREA. FAVORED COOLER OF GUIDANCE HIGHS WED
WITH PLENTY OF CLOUDS EXPECTED...SCT -SHRA/TSRA POSSIBLE MUCH OF THE
DAY AND THE DRIER SFC-925MB LAYER FOR EVAPORATIVE COOLING IN/AROUND
ANY RAIN. WITH SOME CLEARING/DRYING AND STRONGER SFC-850MB COLD
ADVECTION BY/AFTER MIDNIGHT...FAVORED COOLER OF GUIDANCE LOWS FOR
WED NIGHT.
.LONG TERM...THURSDAY THROUGH SUNDAY
346 AM CDT MON APR 23 2012
AGREEMENT IMPROVING AMONG MEDIUM RANGE MODELS WITH THE 23.00Z RUNS.
UPPER FLOW AMPLIFIES FOR THU WITH STRONG/COLD CAN HIGH PRESSURE
SETTLING INTO THE UPPER MIDWEST FOR THU/THU NIGHT. THU NIGHT LOOKS
QUITE COLD AND MAY YET NEED ANOTHER ROUND OF FROST/FREEZE HEADLINES
FOR MUCH OF THE FCST AREA LATE THU NIGHT/FRI MORNING. NEEDLESS TO
SAY TEMPS TO END THE WEEK...AND THE WEEKEND...TREND BELOW NORMAL.
TROUGHING MOVING THRU THE WESTERN CONUS INTO THE PLAINS BEGINS TO
SEND ENERGY AND MOISTURE TOWARD THE AREA ALREADY LATER THRU NIGHT
AND FRI. PLENTY OF MODEL DETAIL/SHORTWAVE TIMING DIFFERENCES BY THIS
TIME. TREND OF MODELS FRI/SAT IS STRONGER/FURTHER NORTH WITH THE SFC
LOW AND THE LEAD ENERGY WITH THE TROUGH LIFTING INTO THE CENTRAL
PLAINS AND TOWARD THE AREA. MODELS FURTHER NORTH/ STRONGER WITH THE
LOWER LEVEL FORCING/LIFT/MOISTURE TO MOVE ACROSS THE MID/UPPER MS
VALLEY. 20-40 PERCENT SHRA CHANCES FOR MUCH OF FRI INTO SUN...
HIGHEST ACROSS THE SOUTH...LOOK GOOD FOR NOW UNTIL MODEL
TIMING/LATITUDE DETAILS SETTLE DOWN. DID LIMIT TSRA CHANCES FOR MUCH
OF FRI-SAT TO NORTHEAST IA/FAR SOUTHWEST WI CLOSER TO CURRENT
EXPECTED WARM FRONT/LOW TRACK. MODEL CONSENSUS DATA IN FCST GRIDS
FOR THU-SUN APPEARS WELL TRENDED FOR NOW.
&&
.AVIATION...THROUGH 06Z TUESDAY NIGHT
1105 PM CDT SUN APR 22 2012
A WEAK UPPER LEVEL SHORTWAVE TROUGH WILL KEEP A DECK OF 6-8 KFT
CLOUDS ACROSS THE TAF SITES THROUGH 07-08Z...SCATTERING OUT AFTER
THAT. HOWEVER...THE 00Z NAM12/GFS40 AND LATEST RUC13 ALL POINT TO A
SWATH OF SOMEWHAT LOWER SATURATION SLIDING ACROSS WESTERN WI BETWEEN
09-12Z. THIS LOOKS ASSOCIATED WITH SOME 3-6 KFT CEILINGS NEAR THE
TIP OF LAKE SUPERIOR. WILL ADD SOME MENTION OF BKN CIGS IN THIS TIME
FRAME FOR KLSE...BUT WILL KEEP OUT OF KRST FOR NOW. OVERALL
THOUGH...VFR CONDITIONS SHOULD PERSIST INTO MONDAY NIGHT.
WINDS WILL STAY FROM A NORTHERN DIRECTION THROUGH MONDAY. GOOD
MIXING WILL LEAD TO SOME LATE MORNING/AFTERNOON GUSTINESS UPWARDS OF
20+ KTS. WINDS SHOULD DIE OFF VERY QUICKLY MONDAY EVENING AS THE
NOCTURNAL INVERSION SETS UP AND HIGH PRESSURE INFLUENCES THE REGION.
LOOK FOR A RETURN OF SOME HIGH LEVEL CLOUDS BEFORE MIDNIGHT AS MORE
MOISTURE SPILLS ACROSS THE UPPER LEVEL RIDGE AND ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY.
&&
.FIRE WEATHER...THIS AFTERNOON
346 AM CDT MON APR 23 2012
LITTLE HAS CHANGED WITH CRITICAL FIRE WEATHER POTENTIAL ACROSS
CENTRAL...NORTH CENTRAL...AND PORTIONS OF SOUTHWEST WI THIS
AFTERNOON. MODEL SOUNDINGS CONTINUE TO INDICATED DEEP MIXING THIS
AFTERNOON WITH DEW POINTS ALONG/EAST OF ROUGHLY A KOVS-BLACK RIVER
FALLS LINE LOWERING INTO THE MID/UPPER 20S AND MINIMUM RELATIVE
HUMIDITY VALUES FALLING INTO THE 20 TO 25 PERCENT RANGE. THE DEEP
MIXING WILL ALSO ALLOW FOR 15-25 MPH WINDS ALOFT TO MIX TO THE
SFC...MAKING FOR GUSTY NORTHWEST TO NORTH WINDS DURING THE PEAK
HEATING PART OF THE DAY. THE WINDS WILL QUICKLY DIMINISH THIS
EVENING AS SURFACE HEATING DECREASES. ALONG/WEST OF THE MISSISSIPPI
RIVER...LIGHTER WINDS ARE EXPECTED ALONG WITH MINIMUM RELATIVE
HUMIDITY VALUES IN THE 28 TO 34 PERCENT RANGE...BUT CONDITIONS IN
THESE AREAS THIS AFTERNOON WILL HAVE TO BE WATCHED AS WELL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
346 AM CDT MON APR 23 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....RRS
LONG TERM......RRS
AVIATION.......RIECK
FIRE WEATHER...RRS
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1200 AM CDT MON APR 23 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A LOW PRESSURE
SYSTEM MOVING NORTH ALONG THE MID-ATLANTIC COASTLINE...WHILE SURFACE
HIGH PRESSURE STRETCHES FROM NORTHERN QUEBEC TO LAKE SUPERIOR...AND
SOUTH ACROSS THE GREAT PLAINS. A SURFACE TROUGH HAS REMAINED NEARLY
STATIONARY FROM NORTHERN MINNESOTA TO THE CENTRAL MISSISSIPPI RIVER
VALLEY...WHERE BKN-OVC LOW AND MID CLOUDS RESIDE. DRY NE WINDS
HAVE ERODED MUCH OF THE CLOUD COVER OVER NORTH-CENTRAL WISCONSIN
LEAVING ONLY FEW TO SCT CONDITIONS FROM WAUSAU TO LAND O LAKES.
WITH SURFACE FEATURES MOVING VERY LITTLE OVER THE NEXT 24
HOURS...CLOUD COVER AND TEMPS AND HUMIDITIES ARE THE MAIN FORECAST
CONCERNS.
TONIGHT...CLOSED UPPER LOW OVER THE OHIO VALLEY WILL SWING EAST TO
THE MID-ATLANTIC STATES TONIGHT. MEANWHILE...AREA OF HIGH PRESSURE
STRETCHING FROM THE NORTHERN PLAINS TO JAMES BAY WILL DRIFT SLIGHTLY
SOUTHWARD OVER THE WESTERN GREAT LAKES. PESKY AREA OF MID AND HIGH
CLOUDS OVER THE NORTHERN MISSISSIPPI VALLEY WILL ALSO SINK SOUTH AND
WILL PROVIDE SCT TO BKN CONDITIONS OVER THE WESTERN HALF OF THE
FORECAST AREA. NO REAL THREAT OF PRECIP FROM THESE CLOUDS.
OTHERWISE...QUIET CONDITIONS WITH LIGHT WINDS WILL BE IN PLACE. LOW
TEMPS RANGING FROM THE UPPER 20S NORTH TO MID 30S SOUTH.
MONDAY...HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE AREA...BUT
THE PRESSURE GRADIENT WILL TIGHTEN AS A RESULT OF LOW PRESSURE
MOVING NE ACROSS NEW ENGLAND. WILL SEE MOSTLY SUNNY AND WARMER
CONDITIONS...THOUGH WITH A GUSTY NORTH WINDS DEVELOPING IN THE
AFTERNOON. HIGHS MID 50S NORTH TO AROUND 60 DEGREES SOUTH.
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...MAIN FCST CONCERNS
ARE PCPN TRENDS FOR THE MIDWEEK PERIOD AND NEXT WEEKEND.
NW FLOW WILL PREVAIL OVER WISCONSIN EARLY IN THE PERIOD...WITH A
STRONG UPPER RIDGE OVER THE ROCKIES AND AN UPPER LOW LIFTING FROM THE
EASTERN GREAT LAKES INTO QUEBEC. WEAK SFC HIGH PRESSURE SHOULD KEEP
GRB CWA DRY MONDAY NIGHT AND TUESDAY.
LOW PRESSURE OVER THE NORTHERN PLAINS ON TUESDAY EVG IS EXPECTED TO
SHIFT SE INTO ILLINOIS ON WEDNESDAY. A COUPLE JET STREAKS WILL
PASS OVER WI...PUTTING PART OF THE FCST AREA IN THE RRQ. A FAIRLY
STG BAROCLINIC ZONE WILL SET UP OVER THE REGION...WITH ISENT LIFT
DEVELOPING AS LLVL FLOW BECOMES S-SW AHEAD OF AN APPROACHING COLD
FRONT. HAVE CONTINUED WITH THE TREND OF HIGHEST POPS OVER OUR SW
COUNTIES...WHERE BEST MOISTURE...LIFT AND INSTABILITY IS EXPECTED.
WEAK HIGH PRESSURE AND ASSOCIATED DRY AIR WILL ALSO BE SLOW TO
PULL OUT OF NE WI. ALTHOUGH TIMING OF THE MAIN COLD FRONT IS A
QUESTION MARK RIGHT NOW...THE GENERAL CONCENSUS IS THAT IT SHOULD
MOVE THROUGH THE AREA WEDS AFTERNOON AND EVENING. SOME SHOWERS
MAY ALSO BE GENERATED WITH THIS FEATURE.
STRONG CANADIAN HIGH PRESSURE WILL BUILD INTO THE REGION ON
THURSDAY...AND LIKELY LINGER INTO AT LEAST THE EARLY PART OF THE
WEEKEND. FREEZING TEMPERATURES WILL ONCE AGAIN BE POSSIBLE...WITH
THE BEST CHANCE OCCURRING ON THURSDAY NIGHT.
MODELS ARE HAVING DIFFICULTY DETERMINING HOW LONG THE CANADIAN HIGH
WILL PERSIST OVER THE REGION...AND THE TIMING OF AN UPPER TROF
APPROACHING FROM THE PLAINS. THE ECMWF HAS BEEN MORE AGGRESSIVE
BRINGING PCPN INTO THE REGION OVER THE PAST COUPLE DAYS. FOR NOW...
HAVE REMOVED ANY POPS FROM THE SATURDAY FCST...AND KEPT LOW POPS
SAT NGT INTO SUNDAY.
&&
.AVIATION...A DECREASING 7000-9000 FEET MID LEVEL CIG WILL
CONTINUE TO DRIFT OVER PART OF THE REGION OVERNIGHT...OTHERWISE
VFR CONDITIONS EXPECTED THROUGH MONDAY. A DEEPENING LOW PRESSURE
SYSTEM WORKING OVER THE EASTERN SEABOARD OF THE U.S. WILL GENERATE
GUSTY NORTH WINDS OVER THE STATE ON MONDAY.
TDH
&&
.MARINE...THE PRESSURE GRADIENT WILL TIGHTEN TOMORROW AFTERNOON
BETWEEN HIGH PRESSURE OVER THE NORTHERN PLAINS AND LOW PRESSURE OVER
NEW ENGLAND. DO NOT HAVE MUCH INSTABILITY OVER NORTHERN LAKE
MICHIGAN...BUT THE PRESSURE GRADIENT ALONE MAY BE ABLE TO CREATE
SMALL CRAFT CRITERIA WINDS TOMORROW AFTERNOON.
&&
.FIRE WEATHER...AS LOW PRESSURE MOVES NE OVER NEW ENGLAND
TOMORROW...GUSTY NORTH WINDS WILL DEVELOP MONDAY AFTERNOON. THE
PRESSURE GRADIENT WILL BE TIGHTER OVER EASTERN WISCONSIN...WHERE
GUSTS TO AROUND 25 KTS WILL BE POSSIBLE. HIGHER DEWPOINTS FROM
WESTERN WISCONSIN WILL MIGRATE INTO CENTRAL WISCONSIN TOMORROW
AFTERNOON...WHILE NE WISCONSIN WILL SEE THE BEST MIXING AND HAVE
ACCESS TO THE DRIEST AIR. HUMIDITIES MAY FALL INTO THE 15-20 PCT
RANGE OVER THE SANDY SOIL AREAS OF NE WISCONSIN IN THE AFTERNOON
WHERE CRITICAL LEVELS WILL BE REACH FOR HUMIDITY AND WINDS.
TEMPERATURES WILL OBVIOUSLY FALL WELL SHORT EVERYWHERE. AFTER
COORDINATING WITH THE FOREST SERVICE...CONDITIONS ARE A BIT OF
STRETCH FOR A FIRE WEATHER WATCH TOMORROW AFTERNOON.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1105 PM CDT SUN APR 22 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT
300 PM CDT SUN APR 22 2012
MAIN FORECAST CONCERN IS ON TEMPERATURES IN THE NEAR TERM...THEN
PRECIPITATION CHANCES FROM TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
18Z SURFACE ANALYSIS SHOWS A WEAK TROUGH EXTENDING NORTHWARD THROUGH
CENTRAL IOWA INTO CENTRAL MINNESOTA. CLOUDS CONTINUED TO BE FOUND IN
THIS AREA...BUT A DRIER EASTERLY FLOW HAS KEPT MUCH OF THE FORECAST
AREA UNDER SUNNY TO PARTLY CLOUDY SKIES...AS SURFACE DEW POINTS WERE
IN THE LOW TO MID 20S OVER MUCH OF WISCONSIN.
IN THE NEAR TERM...HIGH PRESSURE WILL DROP INTO THE AREA TONIGHT.
WINDS WILL BE LIGHT AND SOME CONCERN FOR FREEZING TEMPERATURES.
HOWEVER...22.12Z NAM AND GFS IS SHOWING SOME 850MB-700MB MOISTURE
SWINGING ACROSS THE AREA OVERNIGHT AND SHOULD KEEP TEMPERATURES FROM
BOTTOMING OUT. WITH THESE CLOUDS...DID GO SLIGHTLY ABOVE GUIDANCE
NUMBERS.
UPPER RIDGE WILL CONTINUE TO BUILD ACROSS THE AREA MONDAY AND
TUESDAY AS SURFACE RIDGE MOVES EASTWARD. AS WINDS TURN SOUTH ON
BACKSIDE OF THE HIGH...WARM ADVECTION WILL BEGIN TO SPREAD INTO THE
AREA FROM THE WEST. 850MB TEMPERATURES OF AROUND +2 TO +3
CELSIUS MONDAY AFTERNOON CLIMBS INTO THE TEENS ACROSS SOUTHEAST
MINNESOTA AND NORTHEAST IOWA BY TUESDAY AFTERNOON...AND THUS
EXPECT HIGHS MONDAY IN THE UPPER 50S TO LOWER 60S...RISING INTO
THE 60S TO LOWER 70S BY TUESDAY. IN ADDITION...MONDAY AFTERNOON
BUFKIT SOUNDINGS SHOW MIXING TO BETWEEN 800MB-750MB TAPPING INTO
TO SOME HIGHER WINDS ALOFT...ESPECIALLY OVER THE EASTERN SECTIONS
OF THE FORECAST AREA. AND WITH THIS MIXING LOWER DEW POINTS ARE
EXPECTED THAN WHAT THE MODELS ARE GIVING RESULTING IN SOME FIRE
WEATHER CONCERNS (SEE FIRE WEATHER SECTION BELOW FOR THE DETAILS)
NEXT SHORTWAVE THEN FLATTENS THE RIDGE TUESDAY NIGHT INTO WEDNESDAY.
MOISTURE NOT OVERLY IMPRESSIVE...BUT PRECIPITABLE WATER DO INCREASE
TO BETWEEN THREE QUARTERS OF AN INCH TO ONE INCH BY WEDNESDAY.
MODELS STILL STRUGGLING A BIT ON PLACEMENT AND TIMING AND THUS
CONTINUED THE MID RANGE PROBABILITIES. 22.12Z GFS A BIT MORE
AGREEMENT WITH MOST UNSTABLE CAPES...WHILE NAM CONFINES 500 J/KG
ACROSS MAINLY THE SOUTHERN SECTIONS. WILL CONTINUE TO MENTION
THUNDER IN THIS TIME FRAME...BUT SEVERE WEATHER IS NOT EXPECTED.
.LONG TERM...THURSDAY THROUGH SUNDAY
300 PM CDT SUN APR 22 2012
MEDIUM RANGE MODELS IN AGREEMENT WITH BUILDING A COOL SURFACE HIGH
INTO THE AREA ON THURSDAY AND WITH THE CLEAR SKIES POTENTIAL EXISTS
FOR SOME FREEZING TEMPERATURES THURSDAY NIGHT...ESPECIALLY ACROSS
THE EASTERN SECTIONS OF THE FORECAST AREA. SURFACE HIGH MOVES EAST
FRIDAY...WITH SHORTWAVE TROUGH PUSHING THROUGH THE PLAINS.
PRECIPITATION WILL BATTLE DRIER AIR NEAR THE HIGH OVER
WISCONSIN...WITH PRECIPITATION PROBABILITIES CONFINED TO THE FAR
SOUTHWEST SECTIONS OF THE FORECAST AREA FRIDAY/FRIDAY NIGHT. STILL
SOME UNCERTAINTY FOR SATURDAY AND SUNDAY...AS GFS WANTS TO BUILD
HIGH BACK INTO THE AREA...WHILE ECMWF SHOVES HIGH EASTWARD ALLOWING
FOR MOISTURE/PRECIPITATION TO MOVE INTO THE AREA FROM THE SOUTHWEST.
FOR NOW WILL KEEP PROBABILITIES IN FOR THIS TIME FRAME BASED ON A
MODEL CONSENSUS.
&&
.AVIATION...
1105 PM CDT SUN APR 22 2012
A WEAK UPPER LEVEL SHORTWAVE TROUGH WILL KEEP A DECK OF 6-8 KFT
CLOUDS ACROSS THE TAF SITES THROUGH 07-08Z...SCATTERING OUT AFTER
THAT. HOWEVER...THE 00Z NAM12/GFS40 AND LATEST RUC13 ALL POINT TO A
SWATH OF SOMEWHAT LOWER SATURATION SLIDING ACROSS WESTERN WI BETWEEN
09-12Z. THIS LOOKS ASSOCIATED WITH SOME 3-6 KFT CEILINGS NEAR THE
TIP OF LAKE SUPERIOR. WILL ADD SOME MENTION OF BKN CIGS IN THIS TIME
FRAME FOR KLSE...BUT WILL KEEP OUT OF KRST FOR NOW. OVERALL
THOUGH...VFR CONDITIONS SHOULD PERSIST INTO MONDAY NIGHT.
WINDS WILL STAY FROM A NORTHERN DIRECTION THROUGH MONDAY. GOOD
MIXING WILL LEAD TO SOME LATE MORNING/AFTERNOON GUSTINESS UPWARDS OF
20+ KTS. WINDS SHOULD DIE OFF VERY QUICKLY MONDAY EVENING AS THE
NOCTURNAL INVERSION SETS UP AND HIGH PRESSURE INFLUENCES THE REGION.
LOOK FOR A RETURN OF SOME HIGH LEVEL CLOUDS BEFORE MIDNIGHT AS MORE
MOISTURE SPILLS ACROSS THE UPPER LEVEL RIDGE AND ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY.
&&
.FIRE WEATHER...
300 PM CDT SUN APR 22 2012
NEAR CRITICAL FIRE WEATHER CONDITIONS POSSIBLE ACROSS CENTRAL...
NORTH CENTRAL...AND PORTIONS OF SOUTHWEST WISCONSIN MONDAY
AFTERNOON. DEEP MIXING MONDAY AFTERNOON WILL ALLOW DEW POINTS TO
PLUMMET...WITH MINIMUM RELATIVE HUMIDITY VALUES FALLING INTO THE 20
TO 25 PERCENT RANGE. IN ADDITION...A TIGHT PRESSURE GRADIENT IS
EXPECTED TO BE IN PLACE EAST OF THE MISSISSIPPI RIVER LEADING TO
NORTH/NORTHWEST WINDS IN THE 10 TO 15 MPH RANGE...WITH GUSTS AROUND
28 MPH POSSIBLE DURING AFTERNOON PEAK HEATING. THE WINDS ARE
EXPECTED TO QUICKLY DIMINISH MONDAY EVENING AS SURFACE HEATING
DECREASES. LOOK FOR HUMIDITIES TO RECOVER QUICKLY AND WINDS TO
RAPIDLY DIMINISH AS HIGH PRESSURE BUILDS IN FROM THE WEST MONDAY
EVENING INTO MONDAY NIGHT. WEST OF THE MISSISSIPPI RIVER...LIGHTER
WINDS ARE EXPECTED ALONG WITH MINIMUM RELATIVE HUMIDITY VALUES IN
THE 28 TO 34 PERCENT RANGE...SO NEAR CRITICAL FIRE WEATHER
CONDITIONS ARE NOT EXPECTED IN THESE AREAS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
300 PM CDT SUN APR 22 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM.....RABERDING
LONG TERM......RABERDING
AVIATION.......RIECK
FIRE WEATHER...RABERDING/WETENKAMP
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1149 PM CDT Tue Apr 24 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
In the short term, primary concerns remain with slight convective
chances through Wednesday along with temperatures.
This afternoon, pesky altocumulus and cirrostratus have limited the
upwards extend of temperatures to some degree. However, many areas
will still climb nearly 10-15 degrees above seasonal normals. The
warmest temperatures this afternoon have been located over central
Kansas and southern Nebraska where many locations are now in the
middle 90s. This airmass will gradually move eastward during the
overnight hours.
Tonight: 18z NAM, high-res WRF and HRRR continue to generate isolated to
scattered showers or thunderstorms late tonight across central and
southeastern Kansas along with western Missouri. This activity seems
to be tied to a weak shortwave expected to cross eastward out of the
central Rockies overnight. A slightly amplified low level jet will
push an additional surge of mid-level moisture eastward, with an
increase in elevated instability above 600 mb. An incredibly dry
lower half of the troposphere should limit widespread precipitation,
but if a thunderstorm could form would have to watch for the
potential for some sort of stronger wind gust or heat burst.
Wednesday: GFS which has handled today`s cloud cover adequately well
is less bullish with mid-level cloud cover with EML shifting further
east. Mid-level AC may fester Wednesday morning in central Missouri,
delaying the rapid warmup. However, the remainder of the CWA will be highly
capped, allowing for a significant warmup to near record levels in some
locations. Fast moving shortwave trough will race into the western
Great Lakes late Wednesday afternoon with a ill-defined surface
trough over northern Missouri. Models still point to little in the
way of development along this boundary as best dynamics are focused
in the Great Lakes with the progressive shortwave. There may be
enough surface convergence for a slightly higher chance for late
afternoon or evening thunderstorms in northeastern Missouri.
Wednesday night and Thursday: Models have again shifted the surface
boundary a bit further south into central Missouri Wednesday night,
with an slightly stronger influence from cooler Canadian air
possible. Northeast winds should hold temperatures still above
normal, but will lower temperatures a few degrees Thursday. By
Thursday night, the next round of warm advection precipitation
should begin as the next upper low begins to eject out of the
southwestern United States.
Dux
Medium Range (Friday through Tuesday)...
A quick deamplification of the upper pattern will bring about a more
progressive and stormier pattern for the extended period. As upper
ridging breaks down over the Midwest, a weak negatively-tilted
shortwave will eject into the Plains early Friday, and quickly
deamplify as it becomes absorbed by mean Great Lakes troughing on
Saturday. The result will be a quickly filling surface low that is
forecast to track across southern or central Missouri Friday night.
Going off the more stable GFS solution suggests a more progressive
and southerly forecast track that keeps much of the forecast area in
the cool sector on Friday. This solution is backed up by the latest
NAM which is even further south. This also sets up a tight
baroclinic region marking the difference between temperatures near
50 across the north and in the mid 70s south. Bulk of precipitation
Friday and Friday night will be focused near and just north of this
boundary, which looks to set up near or just south of the US 50
corridor. Can`t rule out some elevated small hailers on Friday but
any appreciable severe threat will remain south of the boundary, and
capping may keep that threat to a minimum.
Continued to lean toward the more progressive GFS solution for
Saturday and Sunday so brought PoPs lower than consensus numbers for
this period. In continued quasizonal flow, the next wave to impact
the region will arrive Monday night and Tuesday. Surface baroclinic
region will remain south of the region through early next week
maintaining below average temperatures through the period.
Hawblitzel
&&
.CLIMATE...
Record highs for Wednesday:
CITY...........NORMAL HIGH........RECORD HIGH
KANSAS CITY....69 DEGREES.........91 IN 1989
ST. JOESPH.....68 DEGREES.........92 IN 1989
DUX
&&
.AVIATION...
For the 06Z TAFS, VFR conditions are expected through the entire
valid period as dry low and mid level air persists across the region.
This should result in scattered to broken mid to high level clouds.
Light southerly winds will veer southwesterly Wednesday morning but
remain relatively light. A boundary will drift southward into the
vicinity of the terminals Wednesday afternoon. Winds should become
light and variable in the vicinity of the boundary so have included a
tempo group to mention this until a more prevailing northerly wind
kicks in as the boundary slides south. Confidence remains low that
the boundary will be able to trigger any convective activity tomorrow
afternoon given the very warm temperatures aloft so have continued to
no mention any activity at this time.
CDB
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1146 PM CDT TUE APR 24 2012
.UPDATE...
ISSUED AT 918 PM CDT TUE APR 24 2012
GOING FORECAST LOOKS ON TRACK. STILL SOME CONCERN THERE COULD BE
SOME PRECIP MOVING INTO CENTRAL MISSOURI FROM THE WEST BEFORE
SUNRISE...BUT 00Z NAM IS TRICKLING IN ALREADY AND IT`S KEEPING THE
PRECIP WELL WEST OF COLUMBIA. RUC AND HRRR ARE LIKEWISE DRY ACROSS
OUR CWFA...THOUGH THE HRRR IS MUCH MORE AGGRESSIVE IN DEVELOPING
THUNDERSTORMS OVER NEBRASKA NEAR THE 850MB FRONT AND ADVECTING
THEM SOUTHEAST ACROSS MISSOURI. THE HRRR TENDS TO BE A LITTLE OVER
ZEALOUS AT TIMES...SO WILL JUST KEEP THE SLIGHT CHANCE POPS IN
CENTRAL MO FOR NOW.
CARNEY
&&
.SHORT TERM...
ISSUED AT 345 PM CDT TUE APR 24 2012
(TONIGHT)
THE WRMFNT HAS LIFTED NWD THRU MOST OF THE CWA TODAY. THIS FNT WILL
SINK SWWD SLIGHTLY THIS EVENING WITH LOSS OF HEATING. EXPECT WINDS
TO DIMINISH SOMEWHAT TONIGHT. WRN AND SWRN PORTIONS OF THE CWA WILL
STILL HAVE SW FLOW THRU MUCH OF THE NIGHT AND HAVE TRENDED TWD THE
WARMER GUIDANCE FOR TONIGHT.
MAIN QUESTION FOR TONIGHT IS POPS. THE GFS HAS WIDESPREAD QPF ACROSS
MUCH OF THE SRN PORTIONS OF MO AND IL FOR TONIGHT. BELIEVE MUCH OF
THIS IS DUE TO TEMP FALLING TO REACH THE DEWPOINT AT/NEAR THE SFC
BASED ON SOUNDINGS. HOWEVER...THE NAM/LOCAL WRF SUGGEST ELEVATED
INSTABILITY WITH JUST ENUF MOISTURE THAT ISOD TO WDLY SCT TSRA WILL
BE POSSIBLE DURING THE PRE DAWN HOURS. THE BETTER MOISTURE IS
FURTHER S AND THE POPS THAT WERE ADDED ARE MAINLY TO COVER
DIFFERENCES IN PRECIP PLACEMENT.
TRUETT
&&
.LONG TERM...
ISSUED AT 345 PM CDT TUE APR 24 2012
(WEDNESDAY-THURSDAY)
STILL TOUGH TO DETERMINE CONVECTIVE POTENTIAL ON WEDNESDAY. IT
WOULD APPEAR THAT FOR MOST OF THE DAY THE THREAT WILL COME FROM
HIGH BASED CONVECTION DUE TO LARGE SCALE WAA...WITH LOW LEVELS
REMAINING STRONGLY CAPPED DUE TO STRONGLY MIXED EML. WHILE THE
WAA-INDUCED CONVECTION WILL BE MOSTLY PROBABLE EAST OF THE
MISSISSIPPI RIVER DURING THE AFTERNOON AND EARLY EVENING...GETTING THE
FEELING THAT FOR MOST OF THE AREA WE WILL BE IN A WAITING MODE TO
SEE IF CONVERGENCE ALONG THE COLD FRONT LATER IN THE AFTERNOON AND
ESPECIALLY OVERNIGHT WILL BE ABLE TO OVERCOME THE CAP. MODELS DO
NOT SEEM OVERLY OPTIMISTIC ABOUT SURFACE BASED CONVECTION FIRING
WEST OF THE MISSISSIPPI...AND GIVEN HOW DRY THE AMS CURRENTLY IS
OVER MOST OF THE PLAINS ITS CERTAINLY POSSIBLE THAT MODELS ARE TOO
HIGH WITH THEIR LOW LEVEL MOISTURE FORECASTS AND RESULTANT CAPE.
HOWEVER DONT WANT TO TOTALLY GIVE UP ON PRECIP AT THIS POINT IN
TIME WITH SURFACE TEMPERATURES PUSHING INTO THE LM80S. SO...POPS
FOR WED NIGHT WILL RANGE FROM LOW CHANCE OVER MID MO...TO AROUND
50% OVER S IL.
TEMPERATURES WILL BE WELL ABOVE NORMAL ON WEDNESDAY...AND EXACTLY
HOW WARM WILL ULTIMATELY DEPEND ON CLOUD COVER. 80S APPEAR LIKELY
IN MOST AREAS...AND A FEW SPOTS IN MID MO SHOULD BE WITHIN A FEW
DEGREES OF THEIR RECORD HIGHS FOR APRIL 25TH (COU....89 IN 1986).
ALTHOUGH SHORT RANGE MODELS VARY IN SPECIFICS...THEY ALL INDICATE
THAT FRONTAL BOUNDARY WILL BE SHIFTING INTO S MO/S IL ON THURSDAY.
MODELS ARE ONLY FORECASTING MODEST OVERRRUNNING DURING THE
DAY...SO WOULD THINK THAT GREATEST PRECIP THREAT WOULD BE OVER OUR
FAR S COUNTIES...ASSOCIATED WITH THE LOW LEVEL CONVERGENCE NEAR
THE FRONT. GIVEN THE FACT THAT OVER THE PAST FEW DAYS THE SHORT
RANGE MODELS HAVE SLOWED THE FRONTS SOUTHWARD PROGRESSION AND HAVE
INITIATED RETURN FLOW A BIT MORE RAPIDLY WILL KEEP SOME LOW POPS
GOING N OF THE FRONT...OVER THE CENTRAL THIRD OF OUR CWA.
(THURSDAY NIGHT-TUESDAY)
UNSETTLED AND WET IS PROBABLY THE PHRASE THAT DESCRIBES THE UPCOMING
WEATHER FOR THE END OF THIS WORK WEEK. WITH THE APPROACH OF FIRST
SHORTWAVE OVER THE PLAINS ALL MODELS RAMP UP OVERRUNNING THURSDAY
NIGHT...AND AS A RESULT HAVE INCREASED POPS INTO THE LIKELY RANGE
WHERE IT APPEARS LOW LEVEL FORCING WILL BE MAXIMIZED...FROM CENTRAL
AND NE MO TO NEAR THE MISSISSIPPI RIVER. FAIRLY HIGH POPS WILL
CONTINUE FRIDAY...AND ESPECIALLY FRIDAY NIGHT...AS THE UPPER RIDGE
PUSHES EAST AND AFOREMENTIONED SHORTWAVE MOVES INTO THE MID
MISSISSIPPI VALLEY.
SEVERE WEATHER WILL CERTAINLY BE POSSIBLE IN THE THURSDAY
NIGHT-FRIDAY NIGHT TIME FRAME...WITH ELEVATED SEVERE STORM THREAT
(MAINLY HAIL) DURING THE FIRST PART OF THE PERIOD FOLLOWED BY A MORE
SURFACED-BASED THREAT WHICH WOULD INCLUDE THE ENTIRE SEVERE WEATHER
SPECTRUM BY LATE FRIDAY AND FRIDAY NIGHT AS STRONG WAVES PROPAGATES
ALONG THE STALLED BOUNDARY. SOME LOCALIZED HYDRO PROBLEMS WILL
MAY ALSO BE POSSIBLE.
TEMPERATURES ARE GOING TO BE VERY TRICKY ON FRIDAY...DEPENDING ON
THE ACTUAL POSITION OF THE FRONT. ITS CERTAINLY POSSIBLE THAT
NORTHERN PARTS OF OUR AREA MAY STRUGGLE TO REACH THE LOWER
50S...WHILE OUR FAR S COUNTIES COULD BE IN THE 70S.
RAIN THREAT SHOULD DIMINISH SATURDAY AND SATURDAY NIGHT AS FRONTAL
BOUNDARY OOZES BACK TO THE SOUTH...AND THEN IT LOOKS LIKE WE MAY
SQUEEZE OUT A COUPLE OF DRY DAYS ON SUNDAY AND MONDAY. HOWEVER...
THE FRONT...AND A THREAT OF SHOWERS/THUNDERSTORMS...WILL RETURN BY
TUESDAY. WITH THE CWA REAMING N OF THE FRONT TEMPERATURES IN THE
SATURDAY-TUESDAY TIME FRAME SHOULD BE QUITE COOL...SOME 5 TO 15
DEGREES BELOW NORMAL.
&&
.AVIATION...
ISSUED AT 604 AM CDT TUE APR 24 2012
VFR CONDITIONS ARE EXPECTED. MID LEVEL CLOUD DECK WILL CONTINUE TO
CASCADE SOUTH/SOUTHEAST ACROSS THE FORECAST AREA AS A WARM FRONT
TAKES SHAPE. WILL LIKELY SEE ISO/SCT SHOWERS/STORMS DEVELOP BY
AFTERNOON. WIND WILL GENERALLY BACK FROM SOUTHWEST TO THE
SOUTHEAST THROUGH THE FORECAST.
SPECIFICS FOR KSTL...
VFR CONDITIONS EXPECTED. MID LEVEL CLOUDS WITH ISO/SCT
SHOWERS/STORMS WILL DEVELOP BY NOON. COVERAGE DICTATES ONLY A
VCSH. WIND TO BACK FROM SOUTHWEST TO SOUTHEAST.
CVKING
&&
.AVIATION...
ISSUED AT 1138 PM CDT TUE APR 24 2012
EXPECT VFR CONDITIONS THROUGH THE TAF PERIOD. HAVE LEFT FORECAST
DRY FOR NOW AS THERE REMAINS TOO MUCH UNCERTAINTY WITH WHEN IF ANY
RAIN WILL OCCUR AT THE TAF SITES. THERE IS SOME LOW CHANCE FOR
SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP OVER THE AREA
BETWEEN 09-12Z...AND THEN AGAIN ALONG A COLD FRONT THAT WILL MOVE
SOUTHEAST ACROSS THE REGION LATE WEDNESDAY AFTERNOON AND EVENING.
SPECIFICS FOR KSTL...AS MENTIONED ABOVE...EXPECT VFR CONDTIONS.
THERE IS SOME POTENTIAL FOR THUNDERSTORM DEVELOPMENT OVER THE AREA
ON WEDNESDAY EVENING AS A COLD FRONT MOVES SOUTHEAST THROUGH THE
AREA. TOO MUCH UNCERTAINTY REMAINS AT THIS POINT TO INCLUDE IN THE
TAF FOR NOW.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1222 AM CDT WED APR 25 2012
.AVIATION...06Z KGRI TAF. LIGHT AND VARIABLE WINDS EARLY THIS
MORNING WILL BECOME NORTHERLY BY MID MORNING. THE WIND SHOULD
STILL REMAIN FAIRLY LIGHT. VFR CONDITIONS ARE EXPECTED THROUGHOUT
THE TAF VALID PERIOD WITH SCATTERED HIGH CLOUDS.
&&
.PREV DISCUSSION... /ISSUED 244 PM CDT TUE APR 24 2012/
SHORT TERM...TUESDAY NIGHT THROUGH WEDNESDAY.
UPPER LEVEL ANALYSIS INDICATES A STRONG UPPER LEVEL RIDGE HAS BUILT
IN ACROSS THE WESTERN HALF OF THE UNITED STATES. ALONG THIS RIDGE
AXIS...A SURGE OF VERY WARM 850 MB TEMPS NEAR 28 TO 30 DEGREES
CELSIUS HAS CONTINUED TO TRAVERSE NORTHWARD. AT THE SURFACE...A LOW
PRESSURE SYSTEM PUSHING ACROSS THE NORTHERN PLAINS HAS ALLOWED A
TROUGH AXIS TO MOVE THROUGH THE CENTRAL PLAINS.
STRONG BOUNDARY LAYER MIXING AND INCREASED WINDS MAINLY ACROSS THE
SOUTHERN PORTIONS OF THE FORECAST AREA WILL CONTINUE TO ALLOW
TEMPERATURES TO CLIMB THIS AFTERNOON. SEVERAL SITES ACROSS THE ARE
HAVE ALREADY HIT 90 DEGREES AND COULD EASILY INCREASE A FEW MORE
DEGREES. WITH SUCH WARMING TODAY...AND SEVERAL SITES EASILY
REALIZING CONVECTIVE TEMPS...WE COULD SEE SCATTERED CUMULUS DEVELOP
ACROSS THE REGION THIS AFTERNOON AND MAYBE EVEN A THUNDERSTORM OR
TWO. RUC AND LAPS MODELS BOTH INDICATE SOME INSTABILITY ACROSS THE
REGION.
FOR WEDNESDAY...THE SURFACE LOW PRESSURE SYSTEM IS EXPECTED TO SHIFT
JUST NORTHEAST OF THE REGION...DRAGGING A COLD FRONT ACROSS THE
FORECAST AREA. BY AFTERNOON...WINDS ARE EXPECTED TO SHIFT TO THE
NORTHWEST AND EVENTUALLY NORTH. 850 TEMPERATURES LOOK TO REMAIN
QUITE WARM AGAIN ON WEDNESDAY. WITH MODEL SOUNDINGS INDICATING
PLENTY OF BOUNDARY LAYER MIXING...DO NOT SEE A REASON WHY WEDNESDAY
WILL NOT BE AS WARM AS TODAY.
LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY. FRONTAL BOUNDARY
WHICH PUSHES SOUTH DURING THE DAY WEDNESDAY STALLS ACROSS NORTH
CENTRAL KANSAS WEDNESDAY NIGHT. MODELS...ESPECIALLY THE NAM
INDICATES SOME DECENT MID LEVEL FRONTOGENESIS...BETWEEN H85 AND
H7...ALONG/NORTH OF THE BOUNDARY AFTER MIDNIGHT WEDNESDAY NIGHT WITH
LIFT ALSO ENHANCED AS H7 SHORTWAVE TROUGH LIFTS ACROSS THE CENTRAL
PLAINS. WITH INCREASING LIFT OVERNIGHT WED NIGHT...ADDED IN SOME
LOW POPS.
ON THURSDAY...FRONT RESIDES ACROSS CENTRAL KANSAS TO OUR SOUTH WITH
SURFACE TROUGH/DRYLINE EXTENDING ALONG THE HIGH PLAINS. SREF
INDICATES MUCAPES OF 3000 J/KG ALONG/SOUTH OF THE BOUNDARY WITH 500
TO 1000 OR SO J/KG AHEAD OF DRY LINE ALONG HIGH PLAINS INTO SOUTHERN
NEBRASKA. EFFECTIVE SHEAR PARAMETERS ARE PROGGED BETWEEN 40 AND
50KTS. EASTERLY UPSLOPE FLOW...CONVERGENCE ALONG BOUNDARY AND NEXT
WAVE LIFTING OUT IS EXPECTED TO PROVIDE SUFFICIENT FORCING FOR
CONVECTIVE DEVELOPMENT AND A STRONG TO SEVERE STORM IS POSSIBLE.
OUR WESTERN CWA IS OUTLOOKED IN THE DAY3 FOR SEVERE WEATHER AND THIS
STILL LOOKS REASONABLE BASED ON LATEST MODEL RUNS WITH HAIL/WIND
LOOKING LIKE THE PRIMARY HAZARDS.
LIFT CONTINUES THURSDAY NIGHT AHEAD OF THE UPPER LOW PRESSURE SYSTEM
MOVING OUT OF THE SOUTH CENTRAL ROCKIES. THE ECMWF MAINTAINS A
SLOWER PROGRESSION OF THE SYSTEM THAN OTHER MODELS...AND THE SYSTEM
IS PROGGED TO LIFT ACROSS KANSAS INTO NEBRASKA ON FRIDAY. IT IS
SHAPING UP TO EVOLVE INTO A WIDESPREAD RAINFALL EVENT FROM THURSDAY
NIGHT AND LASTING POTENTIALLY INTO FRIDAY NIGHT WHEN THE SYSTEM
FILLS AND LIFTS TO THE NORTHEAST. INSTABILITY DIMINISHES SO NOT
LOOKING FOR A WHOLE LOT IN THE WAY OF THUNDER BUT SOME DECENT
RAINFALL AMOUNTS ARE POSSIBLE AS PRECIPITABLE WATER VALUES AVERAGE
AROUND AN INCH.
AS WAVE MOVES OFF EARLY IN THE WEEKEND...ANOTHER TROUGH/LOW NOSES
SOUTH ONTO THE PLAINS FM THE NC ROCKIES OVER THE WEEKEND PERIOD.
ALTHOUGH THE WEEKEND ITSELF DOES NOT LOOK LIKE A COMPLETE
RAINOUT...INTERMITTENT CHCS FOR RAINFALL DO EXIST. THE ECMWF
ADVERTISES A COLDER AIRMASS OVER THE WEEKEND COMPARED TO THE GFS
WITH H85 TEMPS DROPPING TO -3 OR -4C IN OUR NORTHERN ZONES...WHILE
THE GFS HAS TRENDED SLIGHTLY WARMER AROUND -2C. WILL KEEP PCPN AS
RAIN SHOWERS UNTIL THESE PERIODS GET CLOSER. CONFIDENCE IS NOT HIGH
REGARDING PCPN CHCS HEADING INTO NEXT WEEK BUT CANNOT ARGUE WITH
ENSEMBLE FORECAST ATTM. TROUGH AXIS LOOKS TO DEPART AROUND THE
TUESDAY TIME FRAME...WITH HEIGHT RISES/MODERATING TEMPS BEHIND THE
SYSTEM.
FOR TEMPS...AFTER HOT CONDITIONS WEDNESDAY...THURSDAY WILL BE COOLER
WITH A FAIRLY SHARP TEMP GRADIENT IN MAX TEMPS N/S...WARMING NEAR
THE FRONTAL ZONE. TEMPS WILL LIKELY STRUGGLE FRIDAY IN
CLOUDS/PCPN...THEN THE COLD AIRMASS SETTLES IN OVER THE WEEKEND.
50S LOOK TO HOLD SAT/SUN INTO MONDAY FOR HIGHS BEFORE AIRMASS MODERATES
TUESDAY. WILL NEED TO CONTINUE TO MONITOR LOW TEMPS FOR
FROST/FREEZE POTENTIAL.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
433 AM CDT WED APR 25 2012
.SHORT TERM...TODAY THROUGH FRIDAY
FORECAST CHALLENGES INCLUDE TEMPERATURES AND PRECIPITATION
COVERAGE/AMOUNTS THURSDAY THROUGH FRIDAY.
CURRENTLY...BASED OFF SURFACE PRESSURE ANALYSIS AND RUC THERMAL
ADVECTION PROGS...IT APPEARS THERE ARE TWO COLD FRONTS PASSING
THROUGH THE CWA OVER THE NEXT 12 TO 18 HOURS. THE FIRST
FRONT...APPX HALF WAY THROUGH THE CWA...IS A RATHER WEAK BOUNDARY
MAINLY A WIND SHIFT FROM SWRLY TO NWRLY...BUT THERE IS SOME VERY
SUBTLE WEAK LOW LEVEL CAA ALREADY OCCURRING BEHIND THIS WIND
SHIFT. THE STRONGER MORE NOTABLE COLD FRONT IS LOCATED BACK OVER
WESTERN AND CENTRAL NORTH DAKOTA AND SHOULD BE SWINGING SOUTH
THROUGH THIS CWA LATER TODAY. TEMPERATURES RIGHT NOW ARE IN THE
50S AND 60S ACROSS THE CWA...A GOOD 20 TO 30 DEGREES ABOVE NORMAL
LOWS. THE EARLIER RAIN SHOWERS AND THUNDERSTORMS HAVE CLEARED THE
CWA...LEAVING JUST SOME SCATTERED/BROKEN MID AND HIGH CLOUDS
AROUND OVER THE CWA.
DIFFICULT TO SAY IF THERE IS ACTUALLY ANOTHER SHORT-WAVE SET TO
WORK THROUGH THE CWA THIS AFTERNOON/EVENING BRINGING WITH IT A
SMALL CHANCE FOR PRECIPITATION. THE 00Z GFS THINKS THERE IS...BUT
IT IS THE ONLY MODEL PAINTING LIGHT QPF OVER THE CWA LATER THIS
EVENING. SO...OPTED TO KEEP TODAY/TONIGHT DRY. BEFORE THE STRONGER
COLD FRONT PASSES THROUGH THIS CWA LATE THIS AFTERNOON THROUGH
LATE TONIGHT...TEMPERATURES SHOULD RECOVER BACK UP INTO THE 70S
AND 80S...PER 925HPA THERMAL PROGS IN THE UPPER TEENS TO LOWER 20S
CELSIUS THIS AFTERNOON.
THURSDAY THROUGH FRIDAY...ALL THE MODELS CONTINUE TO AGREE OVERALL
IN TIMING AND TRACK OF LONGWAVE TROF ENERGY SET TO WORK INTO THE
CENTRAL/NORTHERN PLAINS...BEFORE RUNNING INTO AN UPPER LEVEL
STEERING FLOW BRICK WALL. KEEPING THE CATEGORICAL POPS FOR
THURSDAY NIGHT AND FRIDAY...AND JUST KEPT SOME CHANCE POPS ACROSS
THE WESTERN THIRD OF FORECAST ZONES ON THURSDAY...MAINLY FOR LATE
IN THE AFTERNOON ON THURSDAY. BUFKIT ANALYSIS KEEPS P-TYPE ALL
RAIN...ALTHOUGH LATE IN THE DAY ON FRIDAY...THE NAM MODEL BECOMES
MUCH MORE AGGRESSIVE AT DROPPING MUCH OF THE ATMOSPHERIC COLUMN
BELOW ZERO CELSIUS. THE LOWEST 1000 TO 1500 FT AGL APPEAR TO
REMAIN ABOVE FREEZING...WHICH STILL EFFECTIVELY MELTS
HYDRO-METEORS. THE GFS LOOKS SIMILAR...BUT KEEPS A DEEPER BOTTOM
OF THE ATMOSPHERIC COLUMN ABOVE FREEZING. STILL LOOKS LIKE NEAR TO
BELOW NORMAL TEMPERATURES WILL PREVAIL THURSDAY THROUGH FRIDAY.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
AN UPPER LEVEL TROUGH WILL BE OVER THE ROCKIES TO START THE
PERIOD...WITH SHORTWAVE ENERGY BEING SHUNTED NORTHWARD OVER THE
UPPER MIDWEST THROUGH THE WEEKEND. THE UPPER FLOW THEN BECOMES
NEARLY ZONAL ON MONDAY BEFORE A SHORTWAVE TROUGH TRACKS ACROSS THE
PLAINS ON TUESDAY.
AT THE SURFACE...AN ELONGATED TROUGH OF LOW PRESSURE WILL EXTEND
FROM WESTERN CANADA TO TEXAS WITH PRECIPITATION ONGOING OVER THE
CWA WHEN THE PERIOD STARTS. THE PRECIPITATION LOOKS TO CONTINUE
INTO THE DAY SATURDAY BEFORE COMING TO AN END AS HIGH PRESSURE
DROPS SOUTH OVER THE NORTHERN PLAINS AND GREAT LAKES...AND WILL
STICK WITH HIGH CHANCE TO LIKELY POPS BOTH FRIDAY NIGHT INTO EARLY
SATURDAY. AS THE HIGH PUSHES OFF TO THE EAST...THE REMAINDER OF
THE PERIOD BECOMES SOMEWHAT UNSTABLE AS ANOTHER LOW PRESSURE
TROUGH DEVELOPS TO THE WEST AND BRINGS POTENTIAL ROUNDS OF
PRECIPITATION TO THE CWA SUNDAY THROUGH THE DAY TUESDAY. WITH THE
UNCERTAINTY IN TIMING...WILL KEEP POPS IN THE SCHC/CHC RANGE FOR
NOW.
TEMPERATURES WILL BE COOL TO START THE PERIOD...A GOOD 10 DEGREES
OR SO BELOW NORMAL FOR HIGHS ON SATURDAY. WILL THEN SEE A GRADUAL
WARMING TREND THROUGH THE PERIOD AS H85 TEMPS RISE FROM AROUND
ZERO EARLY SATURDAY TO APPROACHING THE LOWER TEENS BY TUESDAY.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
LOW PRESSURE MOVING ACROSS THE REGION WILL ALLOW FOR SOME VFR
CIGS/VISBY WITH SHOWERS...MOVING EAST THROUGH THE OVERNIGHT HOURS.
WINDS WILL SHIFT FROM SOUTHERLY TO NORTHERLY OVER THE NEXT SEVERAL
HOURS AS WELL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...DORN
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS NASHVILLE TN
1152 PM CDT TUE APR 24 2012
.UPDATE...FOR 06Z AVIATION DISCUSSION.
&&
.AVIATION...06Z AVIATION DISCUSSION.
WILL CONTINUE WITH VCSH REMARK CSV THRU 25/10Z...WITH PCPN POTENTIAL
ENDING AFTER. LLWS REMARKS CONTINUE PER STRENGTHENING WRLY LLJ DYNAMICS
25/05Z-25/14Z. SFC WARM FRONT TO MOVE ACROSS/BECOME ESTABLISHED E
OF AREA BY 26/00Z...ALLOWING FOR SFC GUSTS TO AROUND 20KTS BNA/CKV
BY 25/20Z. ANOTHER UPPER LEVEL SHORTWAVE DISTURBANCE TO RESULT IN
ISO/SCT SHWRS/TSTMS 25/19Z-26/00Z. PER IMPACTS AT TAF SITES WITH
UNCERTAINTY...AND WILL CONTINUE TO ADDRESS WITH VCTS. PER DIURNAL
HEATING ENDING...BELIEVE SHWRS/TSTMS WILL DISSIPATE AFTER 26/02Z.
&&
.PREV DISCUSSION.../ISSUED 1036 PM CDT TUE APR 24 2012/
UPDATE...
WITHIN THE NW FLOW ALOFT...THE BEST CURVATURE AND SHEER IS MOVING
EASTWARD AND AS A RESULT...WE ARE SEEING A PRONOUNCED DECREASE IN
SHOWER COVERAGE OVER MIDDLE TN. WRF...NAM12 AND RUC SOLUTIONS ARE
ALL IN LINE WITH DECREASING THE PRECIP OVERNIGHT.
FOR THE UPDATE WILL REMOVE POPS FOR THE AFT MIDNIGHT PERIOD FOR
MUCH OF WESTERN MIDDLE TN.
REMAINDER OF FCST IN GOOD SHAPE. UPDATE OUT SHORTLY.
PREV DISCUSSION.../ISSUED 701 PM CDT TUE APR 24 2012/
UPDATE...FOR 00Z AVIATION DISCUSSION.
AVIATION...00Z AVIATION DISCUSSION.
MOISTURE BULK ASSOCIATED WITH UPPER LEVEL SHORTWAVE PASSAGE TO PERSIST
ACROSS MAINLY MID STATE ERN HALF THRU 25/06Z...AND WITH DRY LOW
LEVELS...VSBY SHRA OBSTRUCTIONS MARGINAL AT BEST. LLWS PER
STRENGTHENING WRLY LLJ DYNAMICS 25/05Z-25/14Z. SFC WARM FRONT TO
MOVE ACROSS/BECOME ESTABLISHED E OF AREA BY 25/24Z...ALLOWING FOR
SFC GUSTS TO AROUND 20KTS BNA/CKV BY 25/20Z. ANOTHER UPPER LEVEL
SHORTWAVE DISTURBANCE TO RESULT IN ISO/SCT SHWRS/TSTMS 25/19Z-25/24Z.
PER IMPACTS AT TAF SITES WITH UNCERTAINTY...AND WILL ADDRESS VCTS.
PREV DISCUSSION.../ISSUED 626 PM CDT TUE APR 24 2012/
UPDATE...
MODELS AND THE LATEST RADAR ANALYSIS SUPPORTS THE BETTER MOISTURE
AXIS WILL REMAIN ACROSS THE CUMBERLAND PLATEAU THROUGH THIS
EVENING. STILL RATHER DRY IN THE LOWER LEVELS BUT CONDITIONS
SHOULD MOISTEN UP ENOUGH TO ALLOW THE ACTIVITY TO REACH THE GROUND
SOON.
FOR THE FCST WILL MAKE A QUICK UPDATE AND INCREASE POPS ACROSS THE
PLATEAU AND NORTH CENTRAL ZONES. REMAINDER OF FCST IS IN GOOD
SHAPE. STILL SEEING SOME ADDITIONAL SHOWER ACTIVITY UPSTREAM
ACROSS WESTERN KY.
OTW...FCST LOW TEMPS AND WIND SPEEDS STILL LOOK REASONABLE. UPDATE
OUT SHORTLY.
PREV DISCUSSION.../ISSUED 320 PM CDT TUE APR 24 2012/
DISCUSSION...
RADAR IMAGERY THIS AFTERNOON SHOWS SCATTERED BANDS OF LIGHT RAIN
SHOWERS EXTENDING FROM THE PLATEAU WELL TO THE NORTHWEST ACROSS
MO/IL/IN. THIS ACTIVITY IS IN ASSOCIATION WITH A SOUTHWARD MOVING
SHORTWAVE LOCATED OVER THE OHIO VALLEY...AND AN INCREASING WAA
REGIME DUE TO A STRENGTHENING WESTERLY LLJ. GUIDANCE CONTINUES TO
INDICATE SHOWERS WILL INCREASE IN COVERAGE THROUGH THE AFTERNOON
INTO THE EVENING BEFORE DIMINISHING OVERNIGHT...AND HAVE CHANCE
POPS OVER THE NORTHEAST HALF OF THE CWA TO ACCOUNT FOR THIS
ACTIVITY. RAINFALL AMOUNTS ARE ANTICIPATED TO BE QUITE LIGHT WITH
THIS ACTIVITY...AND NO THUNDERSTORMS ARE EXPECTED AS
THERMODYNAMIC PROFILES ARE TOO DRY/STABLE.
A SIGNIFICANT WARMUP IS IN STORE FOR WEDNESDAY AS LLJ CONTINUES TO
INCREASE UP TO 40-50 KNOTS BY LATE IN THE DAY...WITH HIGHS WELL
INTO THE 70S TO AROUND 80. ATMOSPHERE WILL BECOME QUITE UNSTABLE
ACROSS THE MID STATE TOMORROW AFTERNOON BUT REMAIN CAPPED...SO
ONLY ISOLATED POPS ARE INDICATED FOR NOW WITH BEST CHANCES OVER
NORTHEAST ZONES. BETTER RAIN CHANCES APPEAR ACROSS MIDDLE
TENNESSEE LATE WEDNESDAY NIGHT AND ESPECIALLY THURSDAY AS AN
INTENSE 80 KT H5 JET STREAK PUSHES SOUTHWARD INTO THE OHIO VALLEY
IN THE NW FLOW ALOFT...PUSHING A COLD FRONT TOWARDS THE NORTHERN
CWA. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO FORM OVER
THE MIDWEST WEDNESDAY NIGHT AND QUICKLY MOVE SOUTHEAST
TOWARDS/INTO THE CWA THURSDAY MORNING...WITH ADDITIONAL
DEVELOPMENT ALONG AND AHEAD OF THE FRONTAL BOUNDARY LATER ON
THURSDAY INTO THURSDAY NIGHT. SOME STORMS DURING THIS TIMEFRAME
COULD BE STRONG. CONSIDERABLE MODEL DIFFERENCES REMAIN ON HOW FAR
SOUTH FRONTAL BOUNDARY CAN MAKE IT...WITH NAM KEEPING FRONT WELL
TO OUR NORTH...GFS NEAR THE KY BORDER...AND ECMWF MUCH FURTHER
SOUTH NEAR THE AL BORDER. WHERE FRONT ENDS UP WILL LIKELY DEPEND
ON HOW MUCH CONVECTION DEVELOPS AND CONVECTIVE OUTFLOWS CAN
ASSIST IN DRIVING FRONT SOUTHWARD...AND THIS WILL HAVE A BIG
IMPACT ON TEMPS AND POPS FROM THURSDAY INTO FRIDAY WITH A
POTENTIAL SIGNIFICANT THERMAL GRADIENT FROM SOUTH TO NORTH.
BOUNDARY EXPECTED TO LIFT BACK NORTHWARD ON FRIDAY AS DEEP LOW
PRESSURE DEVELOPS OUT IN THE PLAINS STATES. BRIEF DRY PERIOD IN
THE CARDS FOR FRIDAY NIGHT AND SATURDAY BEFORE LOW PRESSURE OUT
WEST PASSES JUST TO OUR NORTH BRINGING A STRONG COLD FRONT THROUGH
THE MID STATE SATURDAY NIGHT INTO EARLY SUNDAY...WITH ANOTHER
ROUND OF SHOWERS AND STORMS. GLOBAL MODELS CONTINUE TO DEPICT MUCH
COOLER AND DRIER WEATHER BEHIND THE FRONT FOR EARLY NEXT WEEK WITH
TEMPS FALLING BACK BELOW NORMAL FOR SEVERAL DAYS.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
31
AREA FORECAST DISCUSSION
NWS JACKSON KY
1113 AM EDT WED APR 25 2012
.UPDATE...
ISSUED AT 1110 AM EDT WED APR 25 2012
THE MAIN UPDATES FOR THIS PERIOD WERE TO ADJUST THE NEAR TERM HOURLY
TEMP AND DEWPOINT CURVES TO MORE ABRUPT RISES TO ACCOUNT FOR THE WARM
FRONT LIFTING FURTHER NE INTO OUR CWA AND INITIAL CLOUDS IN THE
EASTERN TWO THIRDS OF THE CWA AND POPS LATE IN DAY INTO EARLY IN THE
EVENING. HIGHS FOR TODAY STILL APPEAR ON TARGET.
WE HAVE ALSO OPTED TO GO WITH A SLIGHT CHANCE POP ACROSS THE ENTIRE
AREA FOR LATE IN THE FIRST PERIOD. THE MOST RECENT NAM AND HRRR AS
WELL AS 9Z SREF ALL SUPPORT SOME CONVECTION DEVELOPING LATE IN THE
DAY IN THE VICINITY OF THE WARM FRONT. GIVE PROJECTED SHEAR...THIS
CONVECTION LATE IN THE DAY TO EARLY IN THE EVENING COULD BECOME
STRONG TO POSSIBLY MARGINALLY SEVERE. THIS THREAT WILL CONTINUE TO BE
MONITORED.
UPDATE ISSUED AT 703 AM EDT WED APR 25 2012
RADAR TRENDS SUGGEST PRECIP WILL BE OUT OF THE FORECAST AREA WITHIN
ABOUT AN HOUR. HAVE UPDATED GRIDS FOR LATEST RADAR COVERAGE/TRENDS.
WILL ISSUE A NEW ZFP SHORTLY ONCE THE EARLY MORNING PRECIP IS
FINISHED.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 339 AM EDT WED APR 25 2012
ISENTROPIC LIFT ASSOCIATED WITH A WARM FRONT MOVING TOWARD US FROM
THE SOUTHWEST WAS PRESENT OVERNIGHT...AND AN UPPER LEVEL JET STREAK
ON THE WEST SIDE OF AN EAST COAST TROUGH WAS ALSO HAVING AN
INFLUENCE. THE COMBINATION WAS BRINGING WIDESPREAD SHOWERS...AND SOME
ISOLATED THUNDERSHOWERS UPSTREAM. MODELS AGREE THAT THIS ACTIVITY
SHOULD MOVE SOUTHEAST AND WIND DOWN BY 12Z. HOWEVER...PRECIP BEFORE
THEN WILL NECESSITATE A PRE-FIRST PERIOD IN THE ZFP.
AFTER THE EARLY MORNING PRECIP IS DONE...SIGNIFICANT WARMING ALOFT
WILL TEND TO KEEP A CAP ON SURFACE BASED CONVECTION DURING THE DAY.
HOWEVER...NAM FORECAST SOUNDINGS SHOW SOME POTENTIAL FOR CONVECTION
OVER THE NORTHEAST PART OF THE FORECAST AREA BY THE END OF THE
PERIOD. MEANWHILE...IN OUR NORTHEAST COUNTIES THE GFS IS INDICATING
SATURATION IN THE MID- UPPER LEVELS BY THE END OF THE DAY DUE TO
STRONG WARM AIR ADVECTION. IF THIS OCCURS...IT IS QUESTIONABLE
WHETHER OR NOT WE COULD SEE PRECIP...OR JUST VIRGA. CONSIDERING BOTH
VARYING SCENARIOS...A LOW POP IS JUSTIFIED IN OUR NORTHEAST COUNTIES.
THE WARM FRONT IS FORECAST TO MOVE NORTHEAST OVER THE FORECAST AREA
TONIGHT. MODELS ARE GENERATING AN MCS ALONG THE FRONT TONIGHT...BUT
DISAGREE ON LOCATION. AN AVERAGE OF RECENT RUNS PLACES THE MOST
PROBABLE TRACK ACROSS OUR NE COUNTIES...AND WILL CARRY THE HIGHEST
POPS THERE. HOWEVER...WITH THE NATURE OF NOCTURNAL MCS ACTIVITY...
CONFIDENCE IS NOT HIGH. WILL CARRY LIKELY POPS NORTHEAST AND CHANCE
SOUTHWEST. WITH SWIFT FLOW ALOFT AND MCS POTENTIAL...THERE IS CONCERN
FOR A SEVERE THREAT...AS INDICATED BY SLIGHT RISK FROM SPC.
ANY LINGERING PRECIP WITH THE NIGHT TIME SYSTEM SHOULD DWINDLE IN THE
MORNING. THE LOW PRESSURE SYSTEM WHICH FIRST PULLS THE WARM FRONT
THROUGH WILL PASS EASTWARD ON THURSDAY...AND SEND THE FRONT BACK
SOUTH INTO THE REGION AS A COLD FRONT. WILL LOOK FOR SOME LIMITED
POTENTIAL OF CONVECTIVE REDEVELOPMENT ALONG AND AHEAD OF THE FRONT
LATE IN THE DAY THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 PM EDT TUE APR 24 2012
THE MODELS CONTINUE TO SHOW GOOD AGREEMENT ON THE OVERALL FAIRLY
AMPLIFIED LONG WAVE PATTERN TO DOMINATE THE CONUS THROUGH THE WEEKEND
BEFORE DAMPENING BY EARLY NEXT WEEK. THE DETAILS UNFORTUNATELY
REMAIN VERY UNCERTAIN...LEADING TO A LOWER CONFIDENCE FORECAST.
THE MAIN PLAYER FOR OUR WEATHER WILL BE A LINGERING SURFACE FRONTAL
BOUNDARY...WHICH WILL BE DROPPING SOUTH INITIALLY AS A COLD FRONT ON
THURSDAY NIGHT...BEFORE RETURNING TO THE NORTH AS A WARM FRONT BY
FRIDAY...AND THEN STALLING NEAR OR JUST NORTH OF THE AREA THROUGH
THE WEEKEND. CONVECTION WILL PLAY A BIG ROLE IN THIS TYPE OF
PATTERN...SO HAVE STUCK FAIRLY CLOSE TO THE BLENDED SOLUTION THROUGH
THE WEEKEND.
THEREAFTER...HAVE DECIDED TO STICK CLOSER TO THE INHERITED
FORECAST...ALLOWING FOR A PERIOD OF DRY WEATHER FROM SUNDAY NIGHT
THROUGH MONDAY NIGHT. THE LATEST 00Z MODEL RUNS ARE DEVIATING
QUITE A BIT ON THE DETAILS COMPARED TO PREVIOUS RUNS AS THE LONG
WAVE PATTERN TRANSITIONS BACK TO FLATTER FLOW. THIS MAINLY RESULTS
IN LINGERING THE FRONTAL BOUNDARY EVEN LONGER ACROSS THE
AREA...WHICH IS CERTAINLY POSSIBLE IF THIS IS A TRUE TREND.
FOR TEMPERATURES...AGAIN...STUCK CLOSE TO THE BLENDED GUIDANCE...
WITH THE POTENTIAL FOR MODERATE TO LARGE GRADIENTS ACROSS THE AREA
FROM NORTH TO SOUTH.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 703 AM EDT WED APR 25 2012
LOCALIZED MVFR AND IFR WILL OCCUR EARLY THIS MORNING...BUT SHOULD
GIVE WAY TO VFR BY AROUND 14Z...WITH VFR THEN LIKELY LASTING INTO
TONIGHT. THERE IS A SMALL POTENTIAL FOR SHOWERS AND THUNDERSTORMS
DEVELOPING LATE IN THE DAY...BUT THEY WILL BE MORE LIKELY TO HOLD
OFF UNTIL TONIGHT. THE GREATEST PROBABILITY OF THEM WILL BE FROM
ABOUT 03Z-09Z... ESPECIALLY NEAR AND NORTH OF A LINE FROM KIOB TO
KPBX...WITH IFR BEING A THREAT ALONG WITH GUSTY CONVECTIVE WINDS.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...HAL
LONG TERM....GEOGERIAN
AVIATION...HAL
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
655 AM CDT WED APR 25 2012
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
//ISSUED 350 AM CDT WED APR 25 2012//
MID LEVEL TROF NOW NEAR THE W MN BORDER WILL CONTINUE TO DIVE SE
ACRS AREA REACHING E MN BORDER BFR 18Z AS SURFACE LOW IN SE NODAK
REACHES INTO NC IA. SCT SHOWERS HAVE INCREASED SOMEWHAT OVERNIGHT
AHEAD OF UPPER TROF WITH SUFFICIENT ELEVATED INSTABILITY FOR A FEW
THUNDERSTORMS. TEMPS AHEAD OF SFC LOW IN SW MN HAVE WARMED LAST
SEVERAL HOURS WITH CNB CURRENTLY 69 DEGREES.
MAIN PCPN EVENT IN MN CWA WILL BE THE REMAINDER OF TONIGHT AND THIS
MORNING...BUT RAIN AMOUNTS WILL MAINLY BE IN THE .10 RANGE...BUT
BANDED NATURE OF PCPN WILL PRODUCE SOME STREAKS IN THE .25 RANGE.
AS SFC LOW DIVES SE ACRS IA TODAY...IT LEAVES A TROF HANGING BACK
INTO S MN WHICH COULD FOCUS A FEW SHOWERS AND TSTMS AGAIN THIS
AFTERNOON...SO HELD ONTO A LOW POP.
TEMPS WILL BE WARM AGAIN TODAY WITH SUCH A MILD START TO THE DAY.
THEY WILL GRADE FROM AROUND 80 NEAR THE IA BORDER TO AROUND 60 OUT
IN NE CWA IN WI WHERE CLOUDS AND A FEW SHWRS WILL LINGER INTO THE
AFTN.
NORTHERLY WINDS WILL SHOULD STAY IN 10 TO 15 MPH RANGE TONIGHT IN
STRONG CAA AS HIGH PRESSURE BUILDS SOUTH ACROSS CENTRAL CANADA.
THIS WILL BRING SOME VERY DRY AIR INTO THE REGION...ESPECIALLY THE
NE 1/2 OF AREA BEGINNING ON THURSDAY. DRY ENE FLOW WILL LAST INTO
THE WEEKEND ACROSS NE 1/2 OF AREA AS CANADIAN HIGH PRESSURE HEADS
TOWARD HUDSONS BAY. THIS WILL BRING SOME FIRE WEATHER CONCERNS AS
AFTERNOON HUMIDITY MIXES DOWN INTO THE LOWER TO MID 20% RANGE.
UPPER TROF LIFTING OUT OF 4 CORNERS AREA SHOULD BRING SOME LIGHT
PCPN INTO SW AREAS FRIDAY INTO SATURDAY.
TEMPERATURES WILL BE COOL AFTER THE WARM DAY TODAY. WE SHOULD SEE
RATHER LARGE DIURNAL RANGES IN THE EAST IN DRY AIRMASS WITH HIGHS IN
THE 50S AND LOWS DIPPING INTO THE UPPER 20S.
TEMPERATURES MODERATE AGAIN EARLY NEXT WEEK AS UPPER FLOW BECOMES
MORE ZONAL. GFS AND EC BOTH BRING IN NEXT CHANCE OF PCPN LATE
MONDAY/TUESDAY.
&&
.AVIATION.../12Z TAF ISSUANCE/
SFC LOW MOVING INTO WRN MN TO START THIS PERIOD...WITH AN INVERTED
THOUGH EXTENDING NORTH ALONG THE MN/ND BORDER. STRONG WARM
ADVECTION EAST OF THIS FEATURES HAS KEPT SHOWERS GOING MOST OF THE
NIGHT...BUT RUC SHOWS A GOOD DRYING AND ENDING OF SHOWERS FROM
WEST TO EAST THIS MORNING. THUNDER LOOKS TO BE DONE FOR IN THE MPX
AREA...WITH THE THREAT THIS AFTERNOON SHIFTING TO THE SE OF THE
TERMINALS. WILL BE A THREAT FOR MVFR CIGS THIS AFTERNOON OVER
WI...BUT WITH NO CIGS BELOW 7K FT AT THE MOMENT ACROSS NE MN...
FOLLOWED THE IDEA OF THE HRRR FOR CLOUDS /HIGH VFR CIGS EAST/
RATHER THAN THE GFSLAMP /MVFR CIGS FOR EAU/. CONFIDENCE IN WIND
DIRECTION LOW FOR TODAY FOR MN TERMINALS...AS SFC LOW LOOKS TO GO
DOWN THE MN RIVER...WITH THE INVERTED TROUGH WORKING INTO THE WRN
TWIN CITIES. EXPECT NORTH WINDS ALONG THE THROUGH AXIS..WITH NE
WINDS TO THE EAST AND NW WINDS TO THE WEST. TONIGHT...A STRONG
COLD FRONT WILL WORK ACROSS THE AREA...WINDS BECOMING NRLY
EVERYWHERE. MAY SEE SOME 4K FT CLOUDS IMMEDIATELY BEHIND THE
FRONT...BUT NOT EXPECTING ANYTHING WORSE THAN THAT.
KMSP...MOST DIFFICULT PART OF THE FORECAST TODAY WILL BE WIND
DIRECTIONS. WIND DIRECTION BY THE AFTERNOON WILL DEPEND ON HOW FAR
EAST THE SFC THROUGH MAKES IT. AT THE MOMENT..IT LOOKS LIKE IT
WILL BE RIGHT ACROSS THE FIELD...WHICH SHOULD FAVOR A NORTH WIND.
AT ANY RATE...WIND SHIFT IN THE LATE MORNING WILL FORCE A
RECONFIGURATION OF THE RUNWAYS. NOT ANTICIPATING ANY REDEVELOPMENT
OF SHOWERS THIS AFTERNOON...WITH ANY THUNDERSTORM ACTIVITY THIS
AFTERNOON EXPECTED TO BE ABOUT AS FAR NORTH AS LA CROSSE. FOR THE
COLD FRONT TONIGHT...IS THE OUTSIDE SHOT FOR SOME MVFR CIGS...BUT
LOW LEVELS OF THE ATMO LOOK TO REMAIN PRETTY DRY...AND COOLING
BEHIND THE FRONT DOES NOT LOOK TO BE ENOUGH TO GET MUCH IN THE WAY
OF CLOUDS GOING.
//OUTLOOK...WEDNESDAY THROUGH SUNDAY...
.WED NIGHT AND THU...VFR UNDER HIGH PRESSURE.
.THU NIGHT THRU SUN...VFR WITH -SHRA MAINLY SOUTH.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
627 AM CDT WED APR 25 2012
.UPDATE...
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
FORECAST CHALLENGES INCLUDE TEMPERATURES AND PRECIPITATION
COVERAGE/AMOUNTS THURSDAY THROUGH FRIDAY.
CURRENTLY...BASED OFF SURFACE PRESSURE ANALYSIS AND RUC THERMAL
ADVECTION PROGS...IT APPEARS THERE ARE TWO COLD FRONTS PASSING
THROUGH THE CWA OVER THE NEXT 12 TO 18 HOURS. THE FIRST
FRONT...APPX HALF WAY THROUGH THE CWA...IS A RATHER WEAK BOUNDARY
MAINLY A WIND SHIFT FROM SWRLY TO NWRLY...BUT THERE IS SOME VERY
SUBTLE WEAK LOW LEVEL CAA ALREADY OCCURRING BEHIND THIS WIND
SHIFT. THE STRONGER MORE NOTABLE COLD FRONT IS LOCATED BACK OVER
WESTERN AND CENTRAL NORTH DAKOTA AND SHOULD BE SWINGING SOUTH
THROUGH THIS CWA LATER TODAY. TEMPERATURES RIGHT NOW ARE IN THE
50S AND 60S ACROSS THE CWA...A GOOD 20 TO 30 DEGREES ABOVE NORMAL
LOWS. THE EARLIER RAIN SHOWERS AND THUNDERSTORMS HAVE CLEARED THE
CWA...LEAVING JUST SOME SCATTERED/BROKEN MID AND HIGH CLOUDS
AROUND OVER THE CWA.
DIFFICULT TO SAY IF THERE IS ACTUALLY ANOTHER SHORT-WAVE SET TO
WORK THROUGH THE CWA THIS AFTERNOON/EVENING BRINGING WITH IT A
SMALL CHANCE FOR PRECIPITATION. THE 00Z GFS THINKS THERE IS...BUT
IT IS THE ONLY MODEL PAINTING LIGHT QPF OVER THE CWA LATER THIS
EVENING. SO...OPTED TO KEEP TODAY/TONIGHT DRY. BEFORE THE STRONGER
COLD FRONT PASSES THROUGH THIS CWA LATE THIS AFTERNOON THROUGH
LATE TONIGHT...TEMPERATURES SHOULD RECOVER BACK UP INTO THE 70S
AND 80S...PER 925HPA THERMAL PROGS IN THE UPPER TEENS TO LOWER 20S
CELSIUS THIS AFTERNOON.
THURSDAY THROUGH FRIDAY...ALL THE MODELS CONTINUE TO AGREE OVERALL
IN TIMING AND TRACK OF LONGWAVE TROF ENERGY SET TO WORK INTO THE
CENTRAL/NORTHERN PLAINS...BEFORE RUNNING INTO AN UPPER LEVEL
STEERING FLOW BRICK WALL. KEEPING THE CATEGORICAL POPS FOR
THURSDAY NIGHT AND FRIDAY...AND JUST KEPT SOME CHANCE POPS ACROSS
THE WESTERN THIRD OF FORECAST ZONES ON THURSDAY...MAINLY FOR LATE
IN THE AFTERNOON ON THURSDAY. BUFKIT ANALYSIS KEEPS P-TYPE ALL
RAIN...ALTHOUGH LATE IN THE DAY ON FRIDAY...THE NAM MODEL BECOMES
MUCH MORE AGGRESSIVE AT DROPPING MUCH OF THE ATMOSPHERIC COLUMN
BELOW ZERO CELSIUS. THE LOWEST 1000 TO 1500 FT AGL APPEAR TO
REMAIN ABOVE FREEZING...WHICH STILL EFFECTIVELY MELTS
HYDRO-METEORS. THE GFS LOOKS SIMILAR...BUT KEEPS A DEEPER BOTTOM
OF THE ATMOSPHERIC COLUMN ABOVE FREEZING. STILL LOOKS LIKE NEAR TO
BELOW NORMAL TEMPERATURES WILL PREVAIL THURSDAY THROUGH FRIDAY.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
AN UPPER LEVEL TROUGH WILL BE OVER THE ROCKIES TO START THE
PERIOD...WITH SHORTWAVE ENERGY BEING SHUNTED NORTHWARD OVER THE
UPPER MIDWEST THROUGH THE WEEKEND. THE UPPER FLOW THEN BECOMES
NEARLY ZONAL ON MONDAY BEFORE A SHORTWAVE TROUGH TRACKS ACROSS THE
PLAINS ON TUESDAY.
AT THE SURFACE...AN ELONGATED TROUGH OF LOW PRESSURE WILL EXTEND
FROM WESTERN CANADA TO TEXAS WITH PRECIPITATION ONGOING OVER THE
CWA WHEN THE PERIOD STARTS. THE PRECIPITATION LOOKS TO CONTINUE
INTO THE DAY SATURDAY BEFORE COMING TO AN END AS HIGH PRESSURE
DROPS SOUTH OVER THE NORTHERN PLAINS AND GREAT LAKES...AND WILL
STICK WITH HIGH CHANCE TO LIKELY POPS BOTH FRIDAY NIGHT INTO EARLY
SATURDAY. AS THE HIGH PUSHES OFF TO THE EAST...THE REMAINDER OF
THE PERIOD BECOMES SOMEWHAT UNSTABLE AS ANOTHER LOW PRESSURE
TROUGH DEVELOPS TO THE WEST AND BRINGS POTENTIAL ROUNDS OF
PRECIPITATION TO THE CWA SUNDAY THROUGH THE DAY TUESDAY. WITH THE
UNCERTAINTY IN TIMING...WILL KEEP POPS IN THE SCHC/CHC RANGE FOR
NOW.
TEMPERATURES WILL BE COOL TO START THE PERIOD...A GOOD 10 DEGREES
OR SO BELOW NORMAL FOR HIGHS ON SATURDAY. WILL THEN SEE A GRADUAL
WARMING TREND THROUGH THE PERIOD AS H85 TEMPS RISE FROM AROUND
ZERO EARLY SATURDAY TO APPROACHING THE LOWER TEENS BY TUESDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL TODAY AND TONIGHT WITH SCATTERED TO
BROKEN HIGH CLOUDS AOA 20K FEET STREAMING OVER THE REGION. VSBYS
WILL BE UNRESTRICTED.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
SHORT TERM...DORN
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
644 AM CDT WED APR 25 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
643 AM CDT WED APR 25 2012
UPDATE...CONCERNED MORE NOW THAT STORMS WILL NOT DEVELOP THIS
AFTERNOON OVER NORTHEAST IOWA. CERTAINLY THE ENVIRONMENT IS
FAVORABLE FOR SEVERE STORMS SHOULD THEY DEVELOP...BUT CONVECTIVE
INITIATION IS PROBLEMATIC. THERE IS A TRIGGER MECHANISM...BEING
THE SURFACE LOW CURRENTLY IN THE EASTERN DAKOTAS WHICH IS PROGGED
TO MOVE THROUGH NORTHEAST IOWA THIS AFTERNOON. HOWEVER...
INSTABILITY MAY BE LACKING. MODELS SUCH AS THE 25.00Z ECMWF AND
HIRES NMM RUN THAT DEVELOPED CONVECTION IN NORTHEAST IOWA SHOW
DEWPOINTS REACHING INTO THE LOW TO POSSIBLY MID 60S THIS AFTERNOON
ACROSS ALL OF EASTERN IOWA. THE HIGHEST DEWPOINT RIGHT NOW ON A
REGIONAL SCALE IS 56F IN KANSAS CITY. YOU HAVE TO GO DOWN TO THE
DALLAS TX AREA TO FIND A 60F. IT APPEARS EVAPOTRANSPORATION IS
PLAYING A ROLE IN INCREASE THE DEWPOINTS MORESO THAN ADVECTION.
THERE ARE TWO POTENTIAL PROBLEMS WITH THIS: 1. THERE MAY NOT BE
ENOUGH VEGETATION YET FOR EVAPOTRANSPORATION TO TAKE A BIG ROLE.
2. DAYTIME MIXING COULD CAUSE DEWPOINTS TO FALL. MOST MOS GUIDANCE
AS WELL AS THE 25.07Z HRRR ONLY HAS DEWPOINTS REACHING THE LOW TO
MID 50S AT BEST...WHICH IS A HUGE DIFFERENCE IN THE AMOUNT OF
CAPE. ANOTHER ISSUE IS THE PRESENCE OF MID/HIGH CLOUD WHICH COULD
HAMPER THE TEMPERATURE RISE. ON THE OTHER HAND...THE 25.07Z HRRR
IS WARMER THAN WHAT EVEN WE HAVE FORECAST. NOTE THAT THE 25.07Z
HRRR...25.06Z NAM AND 25.00Z HIRES ARW MODELS DO NOT PRODUCE
CONVECTION THIS AFTERNOON.
IN SUMMARY...CONFIDENCE IS VERY LOW ON SEVERE CHANCES THIS
AFTERNOON BECAUSE OF UNCERTAINTY ON THUNDERSTORM DEVELOPMENT.
COORDINATED WITH THE STORM PREDICTION CENTER AND IT IS POSSIBLE
THE SLIGHT RISK AREA GETS COMPLETELY REMOVED FROM OUR FORECAST
AREA FOR THE 13Z DAY 1 OUTLOOK.
PREVIOUS SHORT TERM DISCUSSION ISSUED AT 356 AM:
MAIN FORECAST CONCERNS THIS PACAKGE...SHRA/TSRA CHANCES TODAY INTO
TONIGHT...FROST POTENTIAL THU NIGHT/FRI MORNING...RAIN CHANCES
ACROSS THE SOUTH END OF THE FCST AREA LATE THU NIGHT INTO FRI NIGHT.
DATA ANALYSIS AT 06Z HAD A BROAD AREA OF LOW PRESSURE OVER THE
CENTRAL/NORTHERN PLAINS...CENTERED OVER THE EASTERN DAKOTAS. MAINLY
MID/HIGH CLOUDS WERE INCREASING OVER MN/IA/WI AHEAD OF THE LOW AND
WEAK SHORTWAVE ENERGY MOVING OUT OF THE NORTHERN ROCKIES AND ACROSS
THE NORTHERN PLAINS. SCT SHRA/TSRA WERE INCREASING ACROSS THE
EASTERN DAKOTAS TO WESTERN WI...IN AN AREA OF INCREASING 850-700MB
THETA-E CONVERGENCE/WARM ADVECTION AND FALLING HGTS ALOFT. THESE
FALLING OUT OF CLOUD BASES OF 8K-11K FT. TEMPS WERE MILD ACROSS THE
REGION EARLY THIS MORNING WITH MOST READINGS IN THE 40S TO LOW 60S.
25.00Z MODELS LOOK TO HAVE INITIALIZED WELL...BUT FOR GFS SOME 5F TO
10F TOO HIGH WITH SFC DEW POINTS FROM THE KARX FCST AREA TO EASTERN
KS. SOLUTIONS QUITE SIMILAR...AT LEAST WITH LARGER SCALE FEATURES...
FOR TODAY THRU THU NIGHT THEN DIVERGE A BIT WITH THE SHORTWAVE
TROUGH LIFTING THRU THE CENTRAL PLAINS. DPROG/DT OF 500MB HGTS AT
25.00Z SHOWED MODEL RUNS OF 23.00Z AND 24.00Z ALL VERIFIED WELL
ACROSS NOAM/ EASTERN PAC WITH CONVERGENCE TOWARD A CONSENSUS OF THE
EARLIER RUNS. TREND THRU TONIGHT FAVORS STRONGER OF EARLIER RUNS
WITH THE TROUGH DROPPING ACROSS THE WESTERN GREAT LAKES AND SLOWER
OF EARLIER RUNS WITH ENERGY MOVING INTO SOUTHERN CA. BY THU NIGHT
TREND FAVORS A COMPROMISE OF TIMING/STRENGTH WITH THE CA ENERGY AS
IT LIFTS INTO THE CO/KS/NEB AREA. BETTER CONSENSUS FOR THIS
TROUGH/ENERGY TO WEAK QUICKLY FRI/FRI NIGHT AS IT IS FORCED TO CRASH
INTO/THRU THE MID LEVEL RIDGE AXIS OVER THE MID/UPPER LEVEL MS
VALLEY. NO ONE MODEL WITH CLEARLY BETTER RUN-TO-RUN CONSISTENCY
TODAY THRU FRI NIGHT. CHECK OF OBS VS. MODEL DATA AT 06Z SHOWED ALL
GOOD WITH THE PLAINS LOW. GFS REMAINED TOO HIGH WITH SFC DEW POINTS
ACROSS IA/MO/EASTERN KS. MODELS HAD THE GENERAL IDEA OF THE SCT
SHRA/TSRA FROM THE EASTERN DAKOTAS TO WESTERN WI...BUT MOST WERE TOO
SLOW WITH THE EAST/ SOUTHEAST SPREAD OF THE SHRA AT 06Z AND WILL BE
AT 12Z. WITH THE STRONG TREND TOWARD A TIGHTER CONSENSUS OF THE
EARLIER RUNS...FAVORED A MODEL/ENSEMBLE BLEND. SHORT TERM FCST
CONFIDENCE AVERAGE TO GOOD THIS CYCLE.
IN THE SHORT TERM...BROAD DIVERGENCE ALOFT...LOWER LEVEL MOISTURE
TRANSPORT/THETA-E CONVERGENCE AND WARM ADVECTION/ISENTROPIC LIFT
WILL TRANSLATE ACROSS THE AREA TODAY. STRONGEST/DEEPEST OF THE
FORCING/LIFT WILL BE OVER THE AREA THIS MORNING. MOST OF THE
FORCING IS AT OR ABOVE 700MB WITH SFC-850MB LAYER REMAINING ON THE
DRY SIDE TODAY. MOST PRECIP AMOUNTS TODAY WILL BE ON THE LIGHT SIDE.
WITH MOST MODELS LOOKING TOO LIGHT/SLOW WITH THE SHRA/TSRA EARLY
THIS MORNING...LEFT RAIN CHANCES TODAY IN THE 40-80 PERCENT RANGE
THIS MORNING AND 30-60 PERCENT RANGE THIS AFTERNOON...HIGHEST
NORTH/EAST CLOSER TO THE SHORTWAVE AND SOME BETTER 925-700MB
SATURATION OF THE COLUMN. EVEN MU CAPE REMAINS QUITE LIMITED OVER
THE AREA TODAY...BUT WITH MID/UPPER LEVEL LIFT/DIVERGENCE AND STEEP
MID LEVEL LAPSE RATES ALLOWING FOR ISOLATED/WIDELY SCT TSRA OVER MN
THIS MORNING CONTINUED A WIDELY SCT MENTION OF TSRA THIS MORNING.
CAPE INCREASES THIS AFTERNOON...ESPECIALLY OVER THE SOUTHWEST END OF
THE FCST AREA AS THE LOW TRACKS SOUTHEAST ACROSS IA AND A WEAK SFC
TROUGH REMAINS OVER SOUTHEAST MN/NORTHEAST IA INTO WED EVENING. WITH
SOME WEAK SFC-925MB CONVERGENCE AND THE CAPE...CONTINUED A WIDELY
SCT TSRA MENTION THRU THE AFTERNOON WITH OUTLOOK PER SWODY1
PLAUSIBLE FOR A NARROW TIME WINDOW LATE IN THE AFTERNOON. SYSTEM
EXITS THIS EVENING WITH SFC-700MB COLD ADVECTION/DRYING IN ITS WAKE
SPREADING QUICKLY SOUTH/EAST ACROSS THE FCST AREA DURING THE
EVENING. COOL/DRY CAN HIGH PRESSURE SETTLES SOUTH ACROSS THE REGION
FOR THU INTO FRI.
THU NIGHT CONTINUES TO LOOK LIKE A FAVORABLE SET-UP FOR FROST
OVER THE NORTHEAST THIRD OF THE FCST AREA...UNDER COOLEST 925-850MB
AIRMASS...LIGHTEST WINDS AND WHERE SKIES THU NIGHT WILL STAY CLEAR
THE LONGEST. NEXT LOW AND THE SHORTWAVE TROUGH EJECTING INTO THE
CENTRAL PLAINS QUICKLY SPREAD HIGHER LEVEL MOISTURE/CIRRUS INTO/
ACROSS THE AREA THU NIGHT...WHICH WOULD HAVE AN IMPACT ON
RADIATIONAL COOLING AND FRI MORNINGS LOWS. LEFT FROST MENTION IN
GRIDS ACROSS THE NORTHEAST 1/3 OF THE FCST AREA LATE THU NIGHT/
EARLY FRI...BUT DUE TO THE INCREASING POTENTIAL FOR HIGH CLOUDS
CONFIDENCE WANING ON THE FROST THREAT. WITH THE DEEP/DRY AIRMASS
WITH THE CAN HIGH...ESPECIALLY THE SFC-700MB LAYER...REMOVED MOST OF
THE -SHRA CHANCE FROM THE SOUTHWEST END OF THE FCST AREA LATE THU
NIGHT. SATURATION OF THE LOWER LEVELS OF THE COLUMN REMAIN IN
QUESTION FRI/FRI NIGHT AS FORCING/LIFT WITH THE CENTRAL PLAINS
LOW/SHORTWAVE MOVE TOWARD/JUST SOUTH OF THE AREA. CAN HIGH REMAINS
OVER THE WESTERN GREAT LAKES WITH A COOL/DRY EASTERLY LOW LEVEL
FLOW. REASONABLE MODEL CONSENSUS THAT LIFT WILL OVERCOME THE DRIER
LOW LEVELS WITH COLUMN SATURATION AND SOME -RA OVER THE SOUTHWEST
1/3 OF THE FCST AREA BY FRI NIGHT. RAISED -RA CHANCES OVER THE
SOUTHWEST THIRD OF THE FCST AREA TO 50-70 PERCENT BY FRI NIGHT. WITH
THE INFLUX OF DRY LOW LEVEL AIR ON THE EASTERLY FLOW...EVAPORATIVE
COOLING IN SFC-800MB LAYER FRI NIGHT ON THE NORTH EDGE OF THE PRECIP
SHIELD MAY ALLOW FOR A -RA/-SN MIX OR WET -SN ACROSS NORTHEAST IA/
FAR SOUTHWEST WI. LEFT THIS OUT OF THE GRIDS FOR NOW WITH MIXED
MODEL SIGNALS ON THE LOWER LEVEL COOLING.
FAVORING THE MODEL CONSENSUS...TRENDED TOWARD A BLEND OF THE
GUIDANCE HIGHS/LOWS FOR TODAY THRU FRI NIGHT. HIGHS TODAY REMAIN
TRICKY...ESPECIALLY OVER THE WEST END OF THE FCST AREA DUE TO WHERE
THE SFC LOW TRACKS AND HOW MUCH CLOUDS MAY DECREASE THERE THIS
AFTERNOON.
.LONG TERM...SATURDAY THROUGH TUESDAY
356 AM CDT WED APR 25 2012
25.00Z MEDIUM RANGE MODELS REASONABLY SIMILAR FOR SAT INTO TUE WITH
SHORTWAVE RIDGING BUILDING OVER THE AREA FOR THE WEEKEND THEN A
TROUGH TO SLOWLY PROGRESS ACROSS THE NORTHERN PLAINS INTO THE
REGION MON/TUE. GOOD CONSENSUS FOR THE CAN HIGH PRESSURE CENTERED
OVER THE GREAT LAKES LATE IN THE WEEK REMAINS NEARLY STATIONARY
THRU THE WEEKEND. AFTER A SMALL -RA CHANCE ACROSS THE SOUTH END OF
THE FCST AREA MAINLY SAT MORNING...THE WEEKEND TRENDS COOL AND DRY
WITH CHANCES OF FROST BOTH SAT/SUN NIGHTS. TEMPS BEGIN TO MODERATE
FOR MON/TUE AS THE MID LEVEL RIDGE IS PUSHED EAST OF THE AREA AND
SOUTHWEST FLOW ALOFT SPREADS OVER THE REGION. DEEPER SOUTHERLY LOW
LEVEL MOISTURE RETURN AND INCREASE LOOK TO ARRIVE FOR MON NIGHT/TUE.
MON LOOKS TO REMAIN DRY WITH SOUNDINGS SHOWING A CAPPING INVERSION
NEAR 850MB AND THE COLUMN DRY ABOVE THAT. SHRA AND SHRA/TSRA CHANCES
ARRIVE MON NIGHT/TUE WITH THE MOISTURE AND MID LEVEL TROUGH MOVING
EAST INTO THE REGION...HOWEVER PLENTY OF SMALLER SCALE DETAIL
DIFFERENCES BY DAYS 6/7. MODEL CONSENSUS DATA SET IN THE SAT-TUE
TIME-FRAME MAKES FOR A WELL TRENDED FCST FOR NOW.
&&
.AVIATION...TODAY AND TONIGHT
643 AM CDT WED APR 25 2012
SCATTERED SHOWERS COMING OUT OF AN ALTOSTRATUS DECK WILL CONTINUE
THIS MORNING ACROSS THE UPPER MISSISSIPPI RIVER VALLEY REGION.
THEY ARE EXPECTED TO BE OFF AN ON...BUT ENOUGH OF A FREQUENCY TO
INCLUDE PREDOMINANT -SHRA IN THE TAF FORECASTS. A THUNDERSTORM IS
ALSO POSSIBLE...BUT NOT ENOUGH CONFIDENCE EXISTS TO PUT ONE IN THE
TAF FORECASTS. ANTICIPATING MOST OF THE SHOWERS TO EITHER BE EAST
OR SOUTHEAST OF THE TAF SITES THIS AFTERNOON. NO VISIBILITY
RESTRICTIONS ARE EXPECTED DUE TO PLENTIFUL LOW LEVEL DRY AIR. THIS
SAME DRY AIR WILL KEEP CEILINGS VFR TODAY. HOWEVER...AN MVFR
STRATUS DECK SEEMS LIKELY TO DEVELOP OVER NORTHERN WISCONSIN
TODAY. AS A LOW PRESSURE AREA CROSSES FROM SOUTH DAKOTA INTO NORTHEAST
IOWA TODAY...THEN MOVES FURTHER SOUTHEAST TONIGHT...WINDS TURNING
NORTHEASTERLY MAY PULL THAT MVFR STRATUS DECK INTO THE TAF SITES.
HIGHEST CONFIDENCE IS AT KLSE AND HAVE INCLUDED THE MVFR DECK AT
03Z. WINDS BEGIN TO TURN NORTH BEFORE THE STRATUS GETS TO
KRST...SO CONFIDENCE IS LOWER THERE. FOR NOW...HAVE ONLY WENT WITH
A SCATTERED MVFR DECK...BUT CERTAINLY MONITORING OF THIS STRATUS
POTENTIAL WILL BE NEEDED WITH LATER FORECAST. REGARDING
WINDS...PLAN ON THEM TO REMAIN GENERALLY AROUND OR LESS THAN 10
KT...STRONGEST AT KRST THIS MORNING FROM THE SOUTHEAST. THE NORTH
WINDS BEHIND THE LOW TONIGHT AT KRST COULD ALSO APPROACH 10 KT.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
356 AM CDT WED APR 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
502 PM CDT WED APR 25 2012
.DISCUSSION...
325 PM CDT
THROUGH TONIGHT...
THE WARM FRONT LIES TO OUR SOUTH EXTENDING EASTWARD FROM THE LOW IN
CENTRAL IOWA THROUGH BLOOMINGTON INDIANA. TEMPERATURES JUST NORTH OF
THE WARM FRONT IN THE SOUTHERN PARTS OF THE CWA ARE ALREADY FLIRTING
WITH 80. MODELS PREVIOUSLY INDICATED THAT MOISTURE WOULD ALSO BE ON
THE RISE TODAY...HOWEVER MOISTURE ADVECTION HAS BEEN MEAGER AT BEST.
THE LACK OF MOISTURE WILL HAVE A LARGE IMPACT ON THE LIKELIHOOD OF
CONVECTION THIS AFTERNOON. WHILE SHEAR IS ABUNDANT...THE LACK OF
MOISTURE HAS RESULTED IN CAPE VALUES OF LESS THAN 100 J/KG.
SCATTERED LIGHT SHOWERS OR SPRINKLES WILL CONTINUE TO MOVE ACROSS
THE CWA THIS AFTERNOON WITH ISOLATED TO SCATTERED THUNDERSTORMS
DEVELOPING SOUTH OF I-80. STORMS WILL BE SCATTERED AT BEST AS
DEWPOINTS STILL REMAIN IN THE LOW 40S TO MID 50S...AND DEWPOINTS ARE
EVEN LOWER NORTH OF I-80. ALSO GIVEN THE PROXIMITY TO THE WARM
FRONT...THINKING A FEW THUNDERSTORMS WILL FIRE. AS FAR AS GUIDANCE
IS CONCERNED...THE HRR HAS BEEN THE MOST ACCURATE TODAY.
AS FAR AS SEVERE WEATHER IS CONCERNED...THE THREAT HAS DECREASED
SIGNIFICANTLY OVER THE COURSE OF THE DAY...BUT THE MAIN AREA OF
CONCERN REMAINS SOUTH OF THE I-80 CORRIDOR. AS MENTIONED PREVIOUSLY
THERE IS LITTLE TO NO INSTABILITY AND THE FRONT IS STILL IN CENTRAL
IL. THE 18Z ILX SOUNDING WAS VERY DRY...WITH ONLY 48 J/KG OF CAPE.
THE SOUNDING ALSO FEATURED A COUPLE OF INVERSIONS AND 308 J/KG OF
CIN. SHEAR IS THE ONLY PARAMETER FEATURING FAVORABLE VALUES OF 48
KT IN THE 0-3 KM LAYER. GIVEN THAT THIS AIRMASS WILL BE ADVECTED
NORTH INTO OUR AREA...THINKING ISOLATED SEVERE STORMS ARE POSSIBLE AT
BEST. THE ILX HODOGRAPH HAD A PRONOUNCED HOOK IN THE LOWER LEVELS OF
THE ATMOSPHERE...FAVORABLE FOR TORNADOES...AND THE LCL WAS AROUND
1400 METERS. THEREFORE MAIN THREATS WILL BE ISOLATED
TORNADOES...LARGE HAIL...AND DAMAGING WINDS.
PRECIP MOVES EAST OUT OF THE CWA AROUND MIDNIGHT. COLD AIR ADVECTION
MOVES IN ON THE BACK SIDE OF THE LOW...AND WINDS BACK FROM EAST TO
NORTH BY MORNING.
TOMORROW AND TOMORROW NIGHT...
THE UPPER LEVEL RIDGE DRIFTS EASTWARD AND A SURFACE HIGH MOVES OVER
THE WESTERN GREAT LAKES. WITH COLD AIR ADVECTION IN FULL
SWING...TEMPS WILL BE IN THE LOW TO MID 50S.
FRIDAY AND SATURDAY...
SURFACE HIGH PRESSURE OVER THE WESTERN GREAT LAKES SHIFTS EASTWARD
AS A LOW PRESSURE SYSTEM FORMS IN THE LEE OF THE ROCKIES FRIDAY
AFTERNOON. RAIN MOVES IN AHEAD OF THE LOW LATE FRIDAY AFTERNOON.
NOT ANTICIPATING THUNDERSTORMS WITH THIS SYSTEM AS THE LOW ITSELF
PASSES SOUTH OF THE CWA. MOISTURE DOES LOOK PLENTIFUL WITH PW
VALUES INCREASING TO 1 TO 1.5 INCHES BY SATURDAY MORNING. TEMPS
REMAIN BELOW NORMAL IN THE UPPER 40S TO LOW 50S BOTH DAYS. LOWS
LOOK LIKE THEY WILL REMAIN ABOVE FREEZING.
SUNDAY THROUGH WEDNESDAY...
HIGH PRESSURE SETTLES IN OVER THE WESTERN GREAT LAKES ON SUNDAY. AN
UPWARD TREND IN TEMPS ALSO BEGINS ON SUNDAY. LOW PRESSURE MOVES
NORTH OF THE CWA EARLY NEXT WEEK BRINGING ANOTHER ROUND OF RAIN AND
THUNDER SHOWERS WITH IT. TEMPS LOOK MORE SEASONAL TO SLIGHTLY ABOVE
AVERAGE BY MID NEXT WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* ISOLATED SHOWERS INTO THIS EVENING.
* POSSIBLE MVFR CIGS MID EVENING INTO THURSDAY MORNING.
* GUSTY NORTHEAST WINDS DEVELOPING MID/LATE THURSDAY MORNING. CMS
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE MOVING ACROSS IOWA WILL CONTINUE TO BE THE FOCAL
POINT FOR WEATHER THIS AFTERNOON. ATTACHED TO IT IS A WARM FRONT
THAT IS EXTENDING TO THE EAST...AND SLOWLY LIFTING THROUGH CENTRAL
ILLINOIS. MODEL FORECASTS EARLIER IN THE DAY WERE REALLY
HIGHLIGHTING EXPLOSIVE DEVELOPMENT ACROSS THE FRONT AS THE LOW
SHIFTED THROUGH ILLINOIS. ONE THING ALL GUIDANCE...OUTSIDE OF THE
HRRR...DID WRONG WAS FORECAST THE AMOUNT OF MOISTURE MOVING INTO
THE AREA. MOST MODELS OVERDID DEWPOINT FORECASTS BY 5 TO 7
DEGREES...AND THAT SEVERELY IMPACTED OUTPUT OF CONVECTIVE SCHEMES.
TRENDS NOW INDICATE THAT BULK/ORGANIZATION TO THE SHOWERS MOVING
OVER THE EASTERN TERMINALS WILL BE OVER THE LAKE IN THE NEXT
HOUR...AND ONLY SOME WIDELY SCATTERED SHOWERS WILL REMAIN THROUGH
THE EVENING HOURS. ANY THUNDER SHOULD ALSO REMAIN SOUTH OF THE
TERMINALS...AND CLOSER TO CENTRAL ILLINOIS. DID FOLLOW HRRR TRENDS
FOR PRECIP TIMING/COVERAGE AND INTENSITY WITH THE 18Z PACKAGE. THERE
IS STILL A BIG QUESTION MARK SURROUNDING THE CIG FORECAST THIS
EVENING. WITH THE EXPECTED RAINS...AND FLOW OFF OF THE
LAKE...GUIDANCE DID BRING CIGS DOWN TO A CAT 2 AND INTO THE IFR
REALM...BUT WITH THE LACK OF PRECIP...WOULD ONLY EXPECT CIGS TO
FALL INTO THE LOWER MVFR CATEGORY...AND STAY OUT OF LIFR/IFR.
WINDS WILL REMAIN OUT OF THE NORTH AS THE LOW MOVES EAST...AND
EXPECT SOME DAYTIME GUSTS INTO THE LOWER 20S THURSDAY AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* MEDIUM CONFIDENCE REGARDING PRECIP TRENDS THIS EVENING AND WIND
FORECAST THROUGH THE PERIOD.
* LOW CONFIDENCE REGARDING CIGS...ESPECIALLY OVERNIGHT INTO
THURSDAY MORNING. CMS
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...CHANCE SHRA. SLIGHT CHANCE TSRA OVERNIGHT. OCNL MVFR
CIGS/VIS POSSIBLE.
SATURDAY...MVFR. CHANCE SHRA.
SUNDAY...VFR. WX NIL.
MONDAY...VFR. WX NIL.
TUESDAY...CHANCE AFTERNOON TSRA.
LENNING
&&
.MARINE...
211 PM CDT
I HAVE OPTED TO GO WITH A GALE WARNING FOR THE OPEN WATERS OF LAKE
MICHIGAN ON THURSDAY. A STRONG PUSH OF COLD AIR AND RAPID PRESSURE
RISES...ASSOCIATED WITH SURFACE HIGH PRESSURE BUILDING IN ACROSS THE
WESTERN GREAT LAKES...LOOKS TO SET UP A PERIOD OF GALE FORCE WINDS
DURING THE DAY ON THURSDAY. IT APPEARS GALES MAY BEGAN AS EARLY AS
DAYBREAK ACROSS THE FAR NORTHERN SECTION OF THE LAKE AS A STRONG
PUSH OF COLD AIR BEGINS TO SPILL ACROSS THE LAKE. THESE STRONG WINDS
WILL QUICKLY SPREAD DOWN LAKE MICHIGAN DURING THE MORNING HOURS. THE
OVERALL DURATION OF THE GALE FORCE WINDS LOOKS TO BE ABOUT 6 TO 9
HOURS. I HAVE LEFT THE NEAR SHORES OUT OF THIS GALE WARNING FOR NOW
DUE TO UNCERTAINTIES ON HOW FAR SOUTH THESE STRONG WINDS WILL PUSH.
HOWEVER...A PERIOD OF GALE FORCE GUSTS ARE POSSIBLE ACROSS THE
INDIANA NEAR SHORES DURING THE LATE MORNING AND AFTERNOON HOURS ON
THURSDAY.
THE WINDS WILL QUICKLY ABATE THURSDAY EVENING. THEREFORE...I WILL
RUN THE GALE WARNING THROUGH THURSDAY AFTERNOON. A PERIOD OF LIGHTER
WINDS WILL SET UP ACROSS LAKE MICHIGAN ON FRIDAY AS SURFACE HIGH
PRESSURE DOMINATES. IT DOES APPEAR THAT EASTERLY WINDS WILL PICK UP
IN INTENSITY FRIDAY NIGHT AND SATURDAY AS A SURFACE LOW TRACKS FROM
THE MID MISSISSIPPI VALLEY EASTWARD ACROSS THE OHIO VALLEY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM THURSDAY TO 7 PM
THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741...7 AM THURSDAY TO 10 AM
FRIDAY.
SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...10 AM
THURSDAY TO 10 AM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
325 PM CDT WED APR 25 2012
.DISCUSSION...
325 PM CDT
THROUGH TONIGHT...
THE WARM FRONT LIES TO OUR SOUTH EXTENDING EASTWARD FROM THE LOW IN
CENTRAL IOWA THROUGH BLOOMINGTON INDIANA. TEMPERATURES JUST NORTH OF
THE WARM FRONT IN THE SOUTHERN PARTS OF THE CWA ARE ALREADY FLIRTING
WITH 80. MODELS PREVIOUSLY INDICATED THAT MOISTURE WOULD ALSO BE ON
THE RISE TODAY...HOWEVER MOISTURE ADVECTION HAS BEEN MEAGER AT BEST.
THE LACK OF MOISTURE WILL HAVE A LARGE IMPACT ON THE LIKELIHOOD OF
CONVECTION THIS AFTERNOON. WHILE SHEAR IS ABUNDANT...THE LACK OF
MOISTURE HAS RESULTED IN CAPE VALUES OF LESS THAN 100 J/KG.
SCATTERED LIGHT SHOWERS OR SPRINKLES WILL CONTINUE TO MOVE ACROSS
THE CWA THIS AFTERNOON WITH ISOLATED TO SCATTERED THUNDERSTORMS
DEVELOPING SOUTH OF I-80. STORMS WILL BE SCATTERED AT BEST AS
DEWPOINTS STILL REMAIN IN THE LOW 40S TO MID 50S...AND DEWPOINTS ARE
EVEN LOWER NORTH OF I-80. ALSO GIVEN THE PROXIMITY TO THE WARM
FRONT...THINKING A FEW THUNDERSTORMS WILL FIRE. AS FAR AS GUIDANCE
IS CONCERNED...THE HRR HAS BEEN THE MOST ACCURATE TODAY.
AS FAR AS SEVERE WEATHER IS CONCERNED...THE THREAT HAS DECREASED
SIGNIFICANTLY OVER THE COURSE OF THE DAY...BUT THE MAIN AREA OF
CONCERN REMAINS SOUTH OF THE I-80 CORRIDOR. AS MENTIONED PREVIOUSLY
THERE IS LITTLE TO NO INSTABILITY AND THE FRONT IS STILL IN CENTRAL
IL. THE 18Z ILX SOUNDING WAS VERY DRY...WITH ONLY 48 J/KG OF CAPE.
THE SOUNDING ALSO FEATURED A COUPLE OF INVERSIONS AND 308 J/KG OF
CIN. SHEAR IS THE ONLY PARAMETER FEATURING FAVORABLE VALUES OF 48
KT IN THE 0-3 KM LAYER. GIVEN THAT THIS AIRMASS WILL BE ADVECTED
NORTH INTO OUR AREA...THINKING ISOLATED SEVERE STORMS ARE POSSIBLE AT
BEST. THE ILX HODOGRAPH HAD A PRONOUNCED HOOK IN THE LOWER LEVELS OF
THE ATMOSPHERE...FAVORABLE FOR TORNADOES...AND THE LCL WAS AROUND
1400 METERS. THEREFORE MAIN THREATS WILL BE ISOLATED
TORNADOES...LARGE HAIL...AND DAMAGING WINDS.
PRECIP MOVES EAST OUT OF THE CWA AROUND MIDNIGHT. COLD AIR ADVECTION
MOVES IN ON THE BACK SIDE OF THE LOW...AND WINDS BACK FROM EAST TO
NORTH BY MORNING.
TOMORROW AND TOMORROW NIGHT...
THE UPPER LEVEL RIDGE DRIFTS EASTWARD AND A SURFACE HIGH MOVES OVER
THE WESTERN GREAT LAKES. WITH COLD AIR ADVECTION IN FULL
SWING...TEMPS WILL BE IN THE LOW TO MID 50S.
FRIDAY AND SATURDAY...
SURFACE HIGH PRESSURE OVER THE WESTERN GREAT LAKES SHIFTS EASTWARD
AS A LOW PRESSURE SYSTEM FORMS IN THE LEE OF THE ROCKIES FRIDAY
AFTERNOON. RAIN MOVES IN AHEAD OF THE LOW LATE FRIDAY AFTERNOON.
NOT ANTICIPATING THUNDERSTORMS WITH THIS SYSTEM AS THE LOW ITSELF
PASSES SOUTH OF THE CWA. MOISTURE DOES LOOK PLENTIFUL WITH PW
VALUES INCREASING TO 1 TO 1.5 INCHES BY SATURDAY MORNING. TEMPS
REMAIN BELOW NORMAL IN THE UPPER 40S TO LOW 50S BOTH DAYS. LOWS
LOOK LIKE THEY WILL REMAIN ABOVE FREEZING.
SUNDAY THROUGH WEDNESDAY...
HIGH PRESSURE SETTLES IN OVER THE WESTERN GREAT LAKES ON SUNDAY. AN
UPWARD TREND IN TEMPS ALSO BEGINS ON SUNDAY. LOW PRESSURE MOVES
NORTH OF THE CWA EARLY NEXT WEEK BRINGING ANOTHER ROUND OF RAIN AND
THUNDER SHOWERS WITH IT. TEMPS LOOK MORE SEASONAL TO SLIGHTLY ABOVE
AVERAGE BY MID NEXT WEEK.
JEE
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA ACTIVITY
* CIG TRENDS
* WIND TRENDS
SHEA
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE MOVING ACROSS IOWA WILL CONTINUE TO BE THE FOCAL
POINT FOR WEATHER THIS AFTERNOON. ATTACHED TO IT IS A WARM FRONT
THAT IS EXTENDING TO THE EAST...AND SLOWLY LIFTING THROUGH CENTRAL
ILLINOIS. MODEL FORECASTS EARLIER IN THE DAY WERE REALLY
HIGHLIGHTING EXPLOSIVE DEVELOPMENT ACROSS THE FRONT AS THE LOW
SHIFTED THROUGH ILLINOIS. ONE THING ALL GUIDANCE...OUTSIDE OF THE
HRRR...DID WRONG WAS FORECAST THE AMOUNT OF MOISTURE MOVING INTO
THE AREA. MOST MODELS OVERDID DEWPOINT FORECASTS BY 5 TO 7
DEGREES...AND THAT SEVERELY IMPACTED OUTPUT OF CONVECTIVE SCHEMES.
TRENDS NOW INDICATE THAT BULK/ORGANIZATION TO THE SHOWERS MOVING
OVER THE EASTERN TERMINALS WILL BE OVER THE LAKE IN THE NEXT
HOUR...AND ONLY SOME WIDELY SCATTERED SHOWERS WILL REMAIN THROUGH
THE EVENING HOURS. ANY THUNDER SHOULD ALSO REMAIN SOUTH OF THE
TERMINALS...AND CLOSER TO CENTRAL ILLINOIS. DID FOLLOW HRRR TRENDS
FOR PRECIP TIMING/COVERAGE AND INTENSITY WITH THE 18Z PACKAGE. THERE
IS STILL A BIG QUESTION MARK SURROUNDING THE CIG FORECAST THIS
EVENING. WITH THE EXPECTED RAINS...AND FLOW OFF OF THE
LAKE...GUIDANCE DID BRING CIGS DOWN TO A CAT 2 AND INTO THE IFR
REALM...BUT WITH THE LACK OF PRECIP...WOULD ONLY EXPECT CIGS TO
FALL INTO THE LOWER MVFR CATEGORY...AND STAY OUT OF LIFR/IFR.
WINDS WILL REMAIN OUT OF THE NORTH AS THE LOW MOVES EAST...AND
EXPECT SOME DAYTIME GUSTS INTO THE LOWER 20S THURSDAY AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MODERATE/HIGH CONFIDENCE ON THE PRECIP TRENDS/TIMING
* MODERATE CONFIDENCE ON THE WIND FORECAST
* LOW CONFIDENCE ON THE CIG HEIGHT FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...CHANCE SHRA. SLIGHT CHANCE TSRA OVERNIGHT. OCNL MVFR
CIGS/VIS POSSIBLE.
SATURDAY...MVFR. CHANCE SHRA.
SUNDAY...VFR. WX NIL.
MONDAY...VFR. WX NIL.
TUESDAY...CHANCE AFTERNOON TSRA.
LENNING
&&
.MARINE...
211 PM CDT
I HAVE OPTED TO GO WITH A GALE WARNING FOR THE OPEN WATERS OF LAKE
MICHIGAN ON THURSDAY. A STRONG PUSH OF COLD AIR AND RAPID PRESSURE
RISES...ASSOCIATED WITH SURFACE HIGH PRESSURE BUILDING IN ACROSS THE
WESTERN GREAT LAKES...LOOKS TO SET UP A PERIOD OF GALE FORCE WINDS
DURING THE DAY ON THURSDAY. IT APPEARS GALES MAY BEGAN AS EARLY AS
DAYBREAK ACROSS THE FAR NORTHERN SECTION OF THE LAKE AS A STRONG
PUSH OF COLD AIR BEGINS TO SPILL ACROSS THE LAKE. THESE STRONG WINDS
WILL QUICKLY SPREAD DOWN LAKE MICHIGAN DURING THE MORNING HOURS. THE
OVERALL DURATION OF THE GALE FORCE WINDS LOOKS TO BE ABOUT 6 TO 9
HOURS. I HAVE LEFT THE NEAR SHORES OUT OF THIS GALE WARNING FOR NOW
DUE TO UNCERTAINTIES ON HOW FAR SOUTH THESE STRONG WINDS WILL PUSH.
HOWEVER...A PERIOD OF GALE FORCE GUSTS ARE POSSIBLE ACROSS THE
INDIANA NEAR SHORES DURING THE LATE MORNING AND AFTERNOON HOURS ON
THURSDAY.
THE WINDS WILL QUICKLY ABATE THURSDAY EVENING. THEREFORE...I WILL
RUN THE GALE WARNING THROUGH THURSDAY AFTERNOON. A PERIOD OF LIGHTER
WINDS WILL SET UP ACROSS LAKE MICHIGAN ON FRIDAY AS SURFACE HIGH
PRESSURE DOMINATES. IT DOES APPEAR THAT EASTERLY WINDS WILL PICK UP
IN INTENSITY FRIDAY NIGHT AND SATURDAY AS A SURFACE LOW TRACKS FROM
THE MID MISSISSIPPI VALLEY EASTWARD ACROSS THE OHIO VALLEY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM THURSDAY TO 7 PM
THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741...7 AM THURSDAY TO 10 AM
FRIDAY.
SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...10 AM
THURSDAY TO 10 AM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
303 PM CDT WED APR 25 2012
.DISCUSSION...
344 AM CDT
PRIMARY FORECAST CHALLENGE THIS MORNING IS PRECIP TRENDS/SEVERE
WEATHER POTENTIAL TODAY INTO TONIGHT...FOLLOWED BY TEMPS AND PRECIP
CHANCES LATE IN THE WEEK.
WARM FRONT HUNG UP TO OUR SOUTH EARLY THIS MORNING EXTENDING FROM
LMK WNW TO NEAR UIN TO A SURFACE LOW OVER SOUTH DAKOTA. SURFACE
ANALYSIS HAS MID/UPPER 50 DEGREE DEWPOINTS STREAMING NORTHWARD
ACROSS THE WARM SECTOR...THOUGH EVENING RAOBS WOULD SUGGEST THE
DEPTH/QUALITY OF THE MOISTURE RETURN LEAVES SOMETHING TO BE DESIRED
WITH 925MB GENERALLY AT OR BELOW 10C UNTIL YOU REACH THE GULF COAST.
MODERATELY SOUTHERLY LOW LEVEL FLOW SHOULD RESULT IN SOME GRADUAL
IMPROVEMENT IN THE LOW LEVEL MOISTURE RETURN TODAY. ALOFT A
SHORTWAVE TROUGH IS MOVING INTO WESTERN MN RESULTING IN INCREASING
COVERAGE OF SHOWERS AND ISOLD TSTORMS. THIS FEATURE IS LIKELY TO
MOVE ACROSS OUR AREA THIS MORNING INTO THE EARLY AFTERNOON RESULTING
IN SCT SHRA AND POSSIBLY ISOLD TSTORMS...HOWEVER BETTER INSTABILITY
IS STILL WELL TO OUR SOUTHWEST AND MIDDAY IS NOT EXACTLY A FAVORABLE
TIME FOR ELEVATED CONVECTION TO THRIVE OR/AND INTENSIFY. WILL MAKE A
LAST MINUTE DECISION ON POPS/WX THROUGH EARLY AFTERNOON SHORTLY.
BIGGER WILD CARD AND POTENTIAL PROBLEM WILL BE LATE THIS AFTERNOON
OR MORE LIKELY THIS EVENING. MODELS ALL SUGGEST SFC LOW WILL TRACK
ACROSS CENTRAL ILLINOIS AND SHOULD DRAG WARM FRONT NORTH INTO OUR
SOUTHERN CWA ALONG WITH WARMER AND POTENTIALLY MORE UNSTABLE AIR
MASS. MODELS ARE PRETTY UNANIMOUS IN DEVELOPING CONVECTION OVER OUR
SOUTHERN/SOUTHEASTERN CWA TOWARD 00Z WITH IT THEN LIKELY TO RACE
SOUTHEASTWARD OUT OF THE AREA THIS EVENING. EVENING SOUNDINGS SHOWED
THE PRESENCE OF AN EXPANSIVE AND STRONG ELEVATED MIXED LAYER (EML)
OVER MUCH OF THE CENTRAL CONUS WHICH IS APPARENTLY ALREADY BEING
ADVECTED EASTWARD INTO THE AREA.
GIVEN THE STRONG EML AND ASSOCIATED CAP...QUESTIONABLE MOISTURE
RETURN...UNCERTAINTY REGARDING THE EXTENT OF CLEARING AND
DESTABILIZATION ACROSS THE WARM SECTOR THIS AFTERNOON...AND PROGGED
LATE ARRIVAL OF VORT MAX (CURRENTLY SEEN ON WATER VAPOR MOVING INTO
SOUTHERN MANITOBA) THERE ARE CERTAINLY PLENTY OF POTENTIAL SCENARIOS
THAT COULD RESULT IN LITTLE/NO CONVECTION AND SEVERE THREAT IN OUR
AREA LATE THIS AFTERNOON/EVENING. HAVING SAID THAT...SHEAR PROFILES
(PARTICULARLY DEEP LAYER) ARE FORECAST TO BE VERY FAVORABLE FOR
SUPERCELLS/BOWING SEGMENTS THIS AFTERNOON AND EVENING AND GIVEN THE
STRONG MODEL CONSENSUS ON THUNDERSTORMS DEVELOPING THIS AFTERNOON
OVER CENTRAL INTO SOUTHERN PORTIONS OF NE IL AM RELUCTANT TO
DOWNPLAY THE SEVERE POTENTIAL TODAY TOO MUCH. THE NORTHERN EXTENT OF
THE SEVERE THREAT SHOULD BE LIMITED TO NEAR THE WARM FRONT WHICH
SHOULD STAY SOUTH OF I-80...KEEPING THE SEVERE WEATHER THREAT LOW
FOR AREAS NORTH OF I-80.
TO THE NORTH OF THE WARM FRONT EXPECT EAST WINDS TO LOCK IN TODAY
AND RESULT IN A FAIRLY COOL DAY...PARTICULARLY NEAR THE LAKE WHERE
TEMPS WILL LIKELY HOLD IN THE 50S THROUGH MUCH OF THE DAY. THIS COOL
AIR MASS WILL BE SYNOPTICALLY RE-ENFORCED TONIGHT AS THE LOW MOVES
OFF TO THE EAST AND NORTHERLY WINDS LOCK IN. FORECAST SOUNDINGS ARE
ALL PRETTY OMINOUS LOOKING WITH RESPECT TO POST FRONTAL STRATUS
OVERSPREADING THE AREA TONIGHT AND LINGERING INTO THURSDAY MORNING
BEFORE SCATTERING OUT DURING THE DAY THURSDAY. DESPITE MIXED
AFTERNOON SUNSHINE...TEMPS SHOULD BE RELATIVELY COOL BY LATE APRIL
STANDARDS.
CERTAINLY NO SURPRISE THAT THE MODELS HAVE ALL TRENDED SLOWER WITH
THE EASTWARD PROGRESSION OF THE CUT OFF LOW OFF THE CALIFORNIA
COAST...WITH IT NOW LOOKING LIKE RAIN MAY NOT ARRIVE UNTIL LATER
FRIDAY AFTERNOON OR MORE LIKELY FRIDAY NIGHT. STILL APPEARS AS
THOUGH SYSTEM WILL BE IN A WEAKENING PHASE AS IT RUNS CONFLUENT FLOW
ON THE SOUTHWEST SIDE OF THE DEEPENING HUDSON VORTEX OVER THE NE
CONUS. MODELS REMAIN FAIRLY GENEROUS WITH QPF FRIDAY NIGHT INTO
SATURDAY...ESPECIALLY OVER OUR SOUTHERN CWA...HOWEVER ITS STILL A
BIT EARLY TO GET EXCITED ABOUT A SOAKING RAIN AS THERE WILL BE
LITTLE TIME FOR ANY APPRECIABLE MOISTURE RETURN AND MY CONFIDENCE IN
THE MODELS CORRECTLY HANDLING SUCH A COMPLEX EVOLUTION OF SYSTEMS
ISNT ALL THAT HIGH. NOT TO MENTION THE OLD RULE OF WHEN IN
DROUGHT...KEEP IT OUT (REFERRING TO PRECIP CHANCES) AS DROUGHTS
OFTEN SEEM TO BE SELF-PERPETUATING EVENTS. EASTERLY WINDS AND COOLER
THAN AVERAGE TEMPS SHOULD CONTINUE THROUGH THE WEEKEND AND INTO THE
START OF NEXT WEEK IN THE WAKE OF THIS SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 20Z...
* SHRA ACTIVITY
* CIG TRENDS
* WIND TRENDS
SHEA
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE MOVING ACROSS IOWA WILL CONTINUE TO BE THE FOCAL
POINT FOR WEATHER THIS AFTERNOON. ATTACHED TO IT IS A WARM FRONT
THAT IS EXTENDING TO THE EAST...AND SLOWLY LIFTING THROUGH CENTRAL
ILLINOIS. MODEL FORECASTS EARLIER IN THE DAY WERE REALLY
HIGHLIGHTING EXPLOSIVE DEVELOPMENT ACROSS THE FRONT AS THE LOW
SHIFTED THROUGH ILLINOIS. ONE THING ALL GUIDANCE...OUTSIDE OF THE
HRRR...DID WRONG WAS FORECAST THE AMOUNT OF MOISTURE MOVING INTO
THE AREA. MOST MODELS OVERDID DEWPOINT FORECASTS BY 5 TO 7
DEGREES...AND THAT SEVERELY IMPACTED OUTPUT OF CONVECTIVE SCHEMES.
TRENDS NOW INDICATE THAT BULK/ORGANIZATION TO THE SHOWERS MOVING
OVER THE EASTERN TERMINALS WILL BE OVER THE LAKE IN THE NEXT
HOUR...AND ONLY SOME WIDELY SCATTERED SHOWERS WILL REMAIN THROUGH
THE EVENING HOURS. ANY THUNDER SHOULD ALSO REMAIN SOUTH OF THE
TERMINALS...AND CLOSER TO CENTRAL ILLINOIS. DID FOLLOW HRRR TRENDS
FOR PRECIP TIMING/COVERAGE AND INTENSITY WITH THE 18Z PACKAGE. THERE
IS STILL A BIG QUESTION MARK SURROUNDING THE CIG FORECAST THIS
EVENING. WITH THE EXPECTED RAINS...AND FLOW OFF OF THE
LAKE...GUIDANCE DID BRING CIGS DOWN TO A CAT 2 AND INTO THE IFR
REALM...BUT WITH THE LACK OF PRECIP...WOULD ONLY EXPECT CIGS TO
FALL INTO THE LOWER MVFR CATEGORY...AND STAY OUT OF LIFR/IFR.
WINDS WILL REMAIN OUT OF THE NORTH AS THE LOW MOVES EAST...AND
EXPECT SOME DAYTIME GUSTS INTO THE LOWER 20S THURSDAY AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 20Z...
* MODERATE/HIGH CONFIDENCE ON THE PRECIP TRENDS/TIMING
* MODERATE CONFIDENCE ON THE WIND FORECAST
* LOW CONFIDENCE ON THE CIG HEIGHT FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...CHANCE SHRA. SLIGHT CHANCE TSRA OVERNIGHT. OCNL MVFR
CIGS/VIS POSSIBLE.
SATURDAY...MVFR. CHANCE SHRA.
SUNDAY...VFR. WX NIL.
MONDAY...VFR. WX NIL.
TUESDAY...CHANCE AFTERNOON TSRA.
LENNING
&&
.MARINE...
211 PM CDT
I HAVE OPTED TO GO WITH A GALE WARNING FOR THE OPEN WATERS OF LAKE
MICHIGAN ON THURSDAY. A STRONG PUSH OF COLD AIR AND RAPID PRESSURE
RISES...ASSOCIATED WITH SURFACE HIGH PRESSURE BUILDING IN ACROSS THE
WESTERN GREAT LAKES...LOOKS TO SET UP A PERIOD OF GALE FORCE WINDS
DURING THE DAY ON THURSDAY. IT APPEARS GALES MAY BEGAN AS EARLY AS
DAYBREAK ACROSS THE FAR NORTHERN SECTION OF THE LAKE AS A STRONG
PUSH OF COLD AIR BEGINS TO SPILL ACROSS THE LAKE. THESE STRONG WINDS
WILL QUICKLY SPREAD DOWN LAKE MICHIGAN DURING THE MORNING HOURS. THE
OVERALL DURATION OF THE GALE FORCE WINDS LOOKS TO BE ABOUT 6 TO 9
HOURS. I HAVE LEFT THE NEAR SHORES OUT OF THIS GALE WARNING FOR NOW
DUE TO UNCERTAINTIES ON HOW FAR SOUTH THESE STRONG WINDS WILL PUSH.
HOWEVER...A PERIOD OF GALE FORCE GUSTS ARE POSSIBLE ACROSS THE
INDIANA NEAR SHORES DURING THE LATE MORNING AND AFTERNOON HOURS ON
THURSDAY.
THE WINDS WILL QUICKLY ABATE THURSDAY EVENING. THEREFORE...I WILL
RUN THE GALE WARNING THROUGH THURSDAY AFTERNOON. A PERIOD OF LIGHTER
WINDS WILL SET UP ACROSS LAKE MICHIGAN ON FRIDAY AS SURFACE HIGH
PRESSURE DOMINATES. IT DOES APPEAR THAT EASTERLY WINDS WILL PICK UP
IN INTENSITY FRIDAY NIGHT AND SATURDAY AS A SURFACE LOW TRACKS FROM
THE MID MISSISSIPPI VALLEY EASTWARD ACROSS THE OHIO VALLEY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
212 PM CDT WED APR 25 2012
.DISCUSSION...
344 AM CDT
PRIMARY FORECAST CHALLENGE THIS MORNING IS PRECIP TRENDS/SEVERE
WEATHER POTENTIAL TODAY INTO TONIGHT...FOLLOWED BY TEMPS AND PRECIP
CHANCES LATE IN THE WEEK.
WARM FRONT HUNG UP TO OUR SOUTH EARLY THIS MORNING EXTENDING FROM
LMK WNW TO NEAR UIN TO A SURFACE LOW OVER SOUTH DAKOTA. SURFACE
ANALYSIS HAS MID/UPPER 50 DEGREE DEWPOINTS STREAMING NORTHWARD
ACROSS THE WARM SECTOR...THOUGH EVENING RAOBS WOULD SUGGEST THE
DEPTH/QUALITY OF THE MOISTURE RETURN LEAVES SOMETHING TO BE DESIRED
WITH 925MB GENERALLY AT OR BELOW 10C UNTIL YOU REACH THE GULF COAST.
MODERATELY SOUTHERLY LOW LEVEL FLOW SHOULD RESULT IN SOME GRADUAL
IMPROVEMENT IN THE LOW LEVEL MOISTURE RETURN TODAY. ALOFT A
SHORTWAVE TROUGH IS MOVING INTO WESTERN MN RESULTING IN INCREASING
COVERAGE OF SHOWERS AND ISOLD TSTORMS. THIS FEATURE IS LIKELY TO
MOVE ACROSS OUR AREA THIS MORNING INTO THE EARLY AFTERNOON RESULTING
IN SCT SHRA AND POSSIBLY ISOLD TSTORMS...HOWEVER BETTER INSTABILITY
IS STILL WELL TO OUR SOUTHWEST AND MIDDAY IS NOT EXACTLY A FAVORABLE
TIME FOR ELEVATED CONVECTION TO THRIVE OR/AND INTENSIFY. WILL MAKE A
LAST MINUTE DECISION ON POPS/WX THROUGH EARLY AFTERNOON SHORTLY.
BIGGER WILD CARD AND POTENTIAL PROBLEM WILL BE LATE THIS AFTERNOON
OR MORE LIKELY THIS EVENING. MODELS ALL SUGGEST SFC LOW WILL TRACK
ACROSS CENTRAL ILLINOIS AND SHOULD DRAG WARM FRONT NORTH INTO OUR
SOUTHERN CWA ALONG WITH WARMER AND POTENTIALLY MORE UNSTABLE AIR
MASS. MODELS ARE PRETTY UNANIMOUS IN DEVELOPING CONVECTION OVER OUR
SOUTHERN/SOUTHEASTERN CWA TOWARD 00Z WITH IT THEN LIKELY TO RACE
SOUTHEASTWARD OUT OF THE AREA THIS EVENING. EVENING SOUNDINGS SHOWED
THE PRESENCE OF AN EXPANSIVE AND STRONG ELEVATED MIXED LAYER (EML)
OVER MUCH OF THE CENTRAL CONUS WHICH IS APPARENTLY ALREADY BEING
ADVECTED EASTWARD INTO THE AREA.
GIVEN THE STRONG EML AND ASSOCIATED CAP...QUESTIONABLE MOISTURE
RETURN...UNCERTAINTY REGARDING THE EXTENT OF CLEARING AND
DESTABILIZATION ACROSS THE WARM SECTOR THIS AFTERNOON...AND PROGGED
LATE ARRIVAL OF VORT MAX (CURRENTLY SEEN ON WATER VAPOR MOVING INTO
SOUTHERN MANITOBA) THERE ARE CERTAINLY PLENTY OF POTENTIAL SCENARIOS
THAT COULD RESULT IN LITTLE/NO CONVECTION AND SEVERE THREAT IN OUR
AREA LATE THIS AFTERNOON/EVENING. HAVING SAID THAT...SHEAR PROFILES
(PARTICULARLY DEEP LAYER) ARE FORECAST TO BE VERY FAVORABLE FOR
SUPERCELLS/BOWING SEGMENTS THIS AFTERNOON AND EVENING AND GIVEN THE
STRONG MODEL CONSENSUS ON THUNDERSTORMS DEVELOPING THIS AFTERNOON
OVER CENTRAL INTO SOUTHERN PORTIONS OF NE IL AM RELUCTANT TO
DOWNPLAY THE SEVERE POTENTIAL TODAY TOO MUCH. THE NORTHERN EXTENT OF
THE SEVERE THREAT SHOULD BE LIMITED TO NEAR THE WARM FRONT WHICH
SHOULD STAY SOUTH OF I-80...KEEPING THE SEVERE WEATHER THREAT LOW
FOR AREAS NORTH OF I-80.
TO THE NORTH OF THE WARM FRONT EXPECT EAST WINDS TO LOCK IN TODAY
AND RESULT IN A FAIRLY COOL DAY...PARTICULARLY NEAR THE LAKE WHERE
TEMPS WILL LIKELY HOLD IN THE 50S THROUGH MUCH OF THE DAY. THIS COOL
AIR MASS WILL BE SYNOPTICALLY RE-ENFORCED TONIGHT AS THE LOW MOVES
OFF TO THE EAST AND NORTHERLY WINDS LOCK IN. FORECAST SOUNDINGS ARE
ALL PRETTY OMINOUS LOOKING WITH RESPECT TO POST FRONTAL STRATUS
OVERSPREADING THE AREA TONIGHT AND LINGERING INTO THURSDAY MORNING
BEFORE SCATTERING OUT DURING THE DAY THURSDAY. DESPITE MIXED
AFTERNOON SUNSHINE...TEMPS SHOULD BE RELATIVELY COOL BY LATE APRIL
STANDARDS.
CERTAINLY NO SURPRISE THAT THE MODELS HAVE ALL TRENDED SLOWER WITH
THE EASTWARD PROGRESSION OF THE CUT OFF LOW OFF THE CALIFORNIA
COAST...WITH IT NOW LOOKING LIKE RAIN MAY NOT ARRIVE UNTIL LATER
FRIDAY AFTERNOON OR MORE LIKELY FRIDAY NIGHT. STILL APPEARS AS
THOUGH SYSTEM WILL BE IN A WEAKENING PHASE AS IT RUNS CONFLUENT FLOW
ON THE SOUTHWEST SIDE OF THE DEEPENING HUDSON VORTEX OVER THE NE
CONUS. MODELS REMAIN FAIRLY GENEROUS WITH QPF FRIDAY NIGHT INTO
SATURDAY...ESPECIALLY OVER OUR SOUTHERN CWA...HOWEVER ITS STILL A
BIT EARLY TO GET EXCITED ABOUT A SOAKING RAIN AS THERE WILL BE
LITTLE TIME FOR ANY APPRECIABLE MOISTURE RETURN AND MY CONFIDENCE IN
THE MODELS CORRECTLY HANDLING SUCH A COMPLEX EVOLUTION OF SYSTEMS
ISNT ALL THAT HIGH. NOT TO MENTION THE OLD RULE OF WHEN IN
DROUGHT...KEEP IT OUT (REFERRING TO PRECIP CHANCES) AS DROUGHTS
OFTEN SEEM TO BE SELF-PERPETUATING EVENTS. EASTERLY WINDS AND COOLER
THAN AVERAGE TEMPS SHOULD CONTINUE THROUGH THE WEEKEND AND INTO THE
START OF NEXT WEEK IN THE WAKE OF THIS SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SHRA ACTIVITY
* CIG TRENDS
* WIND TRENDS
SHEA
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE MOVING ACROSS IOWA WILL CONTINUE TO BE THE FOCAL
POINT FOR WEATHER THIS AFTERNOON. ATTACHED TO IT IS A WARM FRONT
THAT IS EXTENDING TO THE EAST...AND SLOWLY LIFTING THROUGH CENTRAL
ILLINOIS. MODEL FORECASTS EARLIER IN THE DAY WERE REALLY
HIGHLIGHTING EXPLOSIVE DEVELOPMENT ACROSS THE FRONT AS THE LOW
SHIFTED THROUGH ILLINOIS. ONE THING ALL GUIDANCE...OUTSIDE OF THE
HRRR...DID WRONG WAS FORECAST THE AMOUNT OF MOISTURE MOVING INTO
THE AREA. MOST MODELS OVERDID DEWPOINT FORECASTS BY 5 TO 7
DEGREES...AND THAT SEVERELY IMPACTED OUTPUT OF CONVECTIVE SCHEMES.
TRENDS NOW INDICATE THAT BULK/ORGANIZATION TO THE SHOWERS MOVING
OVER THE EASTERN TERMINALS WILL BE OVER THE LAKE IN THE NEXT
HOUR...AND ONLY SOME WIDELY SCATTERED SHOWERS WILL REMAIN THROUGH
THE EVENING HOURS. ANY THUNDER SHOULD ALSO REMAIN SOUTH OF THE
TERMINALS...AND CLOSER TO CENTRAL ILLINOIS. DID FOLLOW HRRR TRENDS
FOR PRECIP TIMING/COVERAGE AND INTENSITY WITH THE 18Z PACKAGE. THERE
IS STILL A BIG QUESTION MARK SURROUNDING THE CIG FORECAST THIS
EVENING. WITH THE EXPECTED RAINS...AND FLOW OFF OF THE
LAKE...GUIDANCE DID BRING CIGS DOWN TO A CAT 2 AND INTO THE IFR
REALM...BUT WITH THE LACK OF PRECIP...WOULD ONLY EXPECT CIGS TO
FALL INTO THE LOWER MVFR CATEGORY...AND STAY OUT OF LIFR/IFR.
WINDS WILL REMAIN OUT OF THE NORTH AS THE LOW MOVES EAST...AND
EXPECT SOME DAYTIME GUSTS INTO THE LOWER 20S THURSDAY AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MODERATE/HIGH CONFIDENCE ON THE PRECIP TRENDS
* MODERATE CONFIDENCE ON THE WIND FORECAST
* LOW CONFIDENCE ON THE CIG HEIGHT FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...CHANCE SHRA. SLIGHT CHANCE TSRA OVERNIGHT. OCNL MVFR
CIGS/VIS POSSIBLE.
SATURDAY...MVFR. CHANCE SHRA.
SUNDAY...VFR. WX NIL.
MONDAY...VFR. WX NIL.
TUESDAY...CHANCE AFTERNOON TSRA.
LENNING
&&
.MARINE...
211 PM CDT
I HAVE OPTED TO GO WITH A GALE WARNING FOR THE OPEN WATERS OF LAKE
MICHIGAN ON THURSDAY. A STRONG PUSH OF COLD AIR AND RAPID PRESSURE
RISES...ASSOCIATED WITH SURFACE HIGH PRESSURE BUILDING IN ACROSS THE
WESTERN GREAT LAKES...LOOKS TO SET UP A PERIOD OF GALE FORCE WINDS
DURING THE DAY ON THURSDAY. IT APPEARS GALES MAY BEGAN AS EARLY AS
DAYBREAK ACROSS THE FAR NORTHERN SECTION OF THE LAKE AS A STRONG
PUSH OF COLD AIR BEGINS TO SPILL ACROSS THE LAKE. THESE STRONG WINDS
WILL QUICKLY SPREAD DOWN LAKE MICHIGAN DURING THE MORNING HOURS. THE
OVERALL DURATION OF THE GALE FORCE WINDS LOOKS TO BE ABOUT 6 TO 9
HOURS. I HAVE LEFT THE NEAR SHORES OUT OF THIS GALE WARNING FOR NOW
DUE TO UNCERTAINTIES ON HOW FAR SOUTH THESE STRONG WINDS WILL PUSH.
HOWEVER...A PERIOD OF GALE FORCE GUSTS ARE POSSIBLE ACROSS THE
INDIANA NEAR SHORES DURING THE LATE MORNING AND AFTERNOON HOURS ON
THURSDAY.
THE WINDS WILL QUICKLY ABATE THURSDAY EVENING. THEREFORE...I WILL
RUN THE GALE WARNING THROUGH THURSDAY AFTERNOON. A PERIOD OF LIGHTER
WINDS WILL SET UP ACROSS LAKE MICHIGAN ON FRIDAY AS SURFACE HIGH
PRESSURE DOMINATES. IT DOES APPEAR THAT EASTERLY WINDS WILL PICK UP
IN INTENSITY FRIDAY NIGHT AND SATURDAY AS A SURFACE LOW TRACKS FROM
THE MID MISSISSIPPI VALLEY EASTWARD ACROSS THE OHIO VALLEY.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ261-LMZ362-LMZ364-LMZ366-LMZ563-LMZ565-
LMZ567-LMZ669-LMZ671-LMZ673-LMZ675-LMZ777-LMZ779-LMZ868-
LMZ870-LMZ872-LMZ874-LMZ876-LMZ878...7 AM THURSDAY TO 7 PM
THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741...7 AM THURSDAY TO 10 AM
FRIDAY.
SMALL CRAFT ADVISORY...LMZ742-LMZ743-LMZ744-LMZ745...10 AM
THURSDAY TO 10 AM FRIDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
126 PM CDT WED APR 25 2012
.DISCUSSION...
344 AM CDT
PRIMARY FORECAST CHALLENGE THIS MORNING IS PRECIP TRENDS/SEVERE
WEATHER POTENTIAL TODAY INTO TONIGHT...FOLLOWED BY TEMPS AND PRECIP
CHANCES LATE IN THE WEEK.
WARM FRONT HUNG UP TO OUR SOUTH EARLY THIS MORNING EXTENDING FROM
LMK WNW TO NEAR UIN TO A SURFACE LOW OVER SOUTH DAKOTA. SURFACE
ANALYSIS HAS MID/UPPER 50 DEGREE DEWPOINTS STREAMING NORTHWARD
ACROSS THE WARM SECTOR...THOUGH EVENING RAOBS WOULD SUGGEST THE
DEPTH/QUALITY OF THE MOISTURE RETURN LEAVES SOMETHING TO BE DESIRED
WITH 925MB GENERALLY AT OR BELOW 10C UNTIL YOU REACH THE GULF COAST.
MODERATELY SOUTHERLY LOW LEVEL FLOW SHOULD RESULT IN SOME GRADUAL
IMPROVEMENT IN THE LOW LEVEL MOISTURE RETURN TODAY. ALOFT A
SHORTWAVE TROUGH IS MOVING INTO WESTERN MN RESULTING IN INCREASING
COVERAGE OF SHOWERS AND ISOLD TSTORMS. THIS FEATURE IS LIKELY TO
MOVE ACROSS OUR AREA THIS MORNING INTO THE EARLY AFTERNOON RESULTING
IN SCT SHRA AND POSSIBLY ISOLD TSTORMS...HOWEVER BETTER INSTABILITY
IS STILL WELL TO OUR SOUTHWEST AND MIDDAY IS NOT EXACTLY A FAVORABLE
TIME FOR ELEVATED CONVECTION TO THRIVE OR/AND INTENSIFY. WILL MAKE A
LAST MINUTE DECISION ON POPS/WX THROUGH EARLY AFTERNOON SHORTLY.
BIGGER WILD CARD AND POTENTIAL PROBLEM WILL BE LATE THIS AFTERNOON
OR MORE LIKELY THIS EVENING. MODELS ALL SUGGEST SFC LOW WILL TRACK
ACROSS CENTRAL ILLINOIS AND SHOULD DRAG WARM FRONT NORTH INTO OUR
SOUTHERN CWA ALONG WITH WARMER AND POTENTIALLY MORE UNSTABLE AIR
MASS. MODELS ARE PRETTY UNANIMOUS IN DEVELOPING CONVECTION OVER OUR
SOUTHERN/SOUTHEASTERN CWA TOWARD 00Z WITH IT THEN LIKELY TO RACE
SOUTHEASTWARD OUT OF THE AREA THIS EVENING. EVENING SOUNDINGS SHOWED
THE PRESENCE OF AN EXPANSIVE AND STRONG ELEVATED MIXED LAYER (EML)
OVER MUCH OF THE CENTRAL CONUS WHICH IS APPARENTLY ALREADY BEING
ADVECTED EASTWARD INTO THE AREA.
GIVEN THE STRONG EML AND ASSOCIATED CAP...QUESTIONABLE MOISTURE
RETURN...UNCERTAINTY REGARDING THE EXTENT OF CLEARING AND
DESTABILIZATION ACROSS THE WARM SECTOR THIS AFTERNOON...AND PROGGED
LATE ARRIVAL OF VORT MAX (CURRENTLY SEEN ON WATER VAPOR MOVING INTO
SOUTHERN MANITOBA) THERE ARE CERTAINLY PLENTY OF POTENTIAL SCENARIOS
THAT COULD RESULT IN LITTLE/NO CONVECTION AND SEVERE THREAT IN OUR
AREA LATE THIS AFTERNOON/EVENING. HAVING SAID THAT...SHEAR PROFILES
(PARTICULARLY DEEP LAYER) ARE FORECAST TO BE VERY FAVORABLE FOR
SUPERCELLS/BOWING SEGMENTS THIS AFTERNOON AND EVENING AND GIVEN THE
STRONG MODEL CONSENSUS ON THUNDERSTORMS DEVELOPING THIS AFTERNOON
OVER CENTRAL INTO SOUTHERN PORTIONS OF NE IL AM RELUCTANT TO
DOWNPLAY THE SEVERE POTENTIAL TODAY TOO MUCH. THE NORTHERN EXTENT OF
THE SEVERE THREAT SHOULD BE LIMITED TO NEAR THE WARM FRONT WHICH
SHOULD STAY SOUTH OF I-80...KEEPING THE SEVERE WEATHER THREAT LOW
FOR AREAS NORTH OF I-80.
TO THE NORTH OF THE WARM FRONT EXPECT EAST WINDS TO LOCK IN TODAY
AND RESULT IN A FAIRLY COOL DAY...PARTICULARLY NEAR THE LAKE WHERE
TEMPS WILL LIKELY HOLD IN THE 50S THROUGH MUCH OF THE DAY. THIS COOL
AIR MASS WILL BE SYNOPTICALLY RE-ENFORCED TONIGHT AS THE LOW MOVES
OFF TO THE EAST AND NORTHERLY WINDS LOCK IN. FORECAST SOUNDINGS ARE
ALL PRETTY OMINOUS LOOKING WITH RESPECT TO POST FRONTAL STRATUS
OVERSPREADING THE AREA TONIGHT AND LINGERING INTO THURSDAY MORNING
BEFORE SCATTERING OUT DURING THE DAY THURSDAY. DESPITE MIXED
AFTERNOON SUNSHINE...TEMPS SHOULD BE RELATIVELY COOL BY LATE APRIL
STANDARDS.
CERTAINLY NO SURPRISE THAT THE MODELS HAVE ALL TRENDED SLOWER WITH
THE EASTWARD PROGRESSION OF THE CUT OFF LOW OFF THE CALIFORNIA
COAST...WITH IT NOW LOOKING LIKE RAIN MAY NOT ARRIVE UNTIL LATER
FRIDAY AFTERNOON OR MORE LIKELY FRIDAY NIGHT. STILL APPEARS AS
THOUGH SYSTEM WILL BE IN A WEAKENING PHASE AS IT RUNS CONFLUENT FLOW
ON THE SOUTHWEST SIDE OF THE DEEPENING HUDSON VORTEX OVER THE NE
CONUS. MODELS REMAIN FAIRLY GENEROUS WITH QPF FRIDAY NIGHT INTO
SATURDAY...ESPECIALLY OVER OUR SOUTHERN CWA...HOWEVER ITS STILL A
BIT EARLY TO GET EXCITED ABOUT A SOAKING RAIN AS THERE WILL BE
LITTLE TIME FOR ANY APPRECIABLE MOISTURE RETURN AND MY CONFIDENCE IN
THE MODELS CORRECTLY HANDLING SUCH A COMPLEX EVOLUTION OF SYSTEMS
ISNT ALL THAT HIGH. NOT TO MENTION THE OLD RULE OF WHEN IN
DROUGHT...KEEP IT OUT (REFERRING TO PRECIP CHANCES) AS DROUGHTS
OFTEN SEEM TO BE SELF-PERPETUATING EVENTS. EASTERLY WINDS AND COOLER
THAN AVERAGE TEMPS SHOULD CONTINUE THROUGH THE WEEKEND AND INTO THE
START OF NEXT WEEK IN THE WAKE OF THIS SYSTEM.
IZZI
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 18Z...
* SHRA ACTIVITY
* CIG TRENDS
* WIND TRENDS
SHEA
//DISCUSSION...UPDATED 18Z...
LOW PRESSURE MOVING ACROSS IOWA WILL CONTINUE TO BE THE FOCAL
POINT FOR WEATHER THIS AFTERNOON. ATTACHED TO IT IS A WARM FRONT
THAT IS EXTENDING TO THE EAST...AND SLOWLY LIFTING THROUGH CENTRAL
ILLINOIS. MODEL FORECASTS EARLIER IN THE DAY WERE REALLY
HIGHLIGHTING EXPLOSIVE DEVELOPMENT ACROSS THE FRONT AS THE LOW
SHIFTED THROUGH ILLINOIS. ONE THING ALL GUIDANCE...OUTSIDE OF THE
HRRR...DID WRONG WAS FORECAST THE AMOUNT OF MOISTURE MOVING INTO
THE AREA. MOST MODELS OVERDID DEWPOINT FORECASTS BY 5 TO 7
DEGREES...AND THAT SEVERELY IMPACTED OUTPUT OF CONVECTIVE SCHEMES.
TRENDS NOW INDICATE THAT BULK/ORGANIZATION TO THE SHOWERS MOVING
OVER THE EASTERN TERMINALS WILL BE OVER THE LAKE IN THE NEXT
HOUR...AND ONLY SOME WIDELY SCATTERED SHOWERS WILL REMAIN THROUGH
THE EVENING HOURS. ANY THUNDER SHOULD ALSO REMAIN SOUTH OF THE
TERMINALS...AND CLOSER TO CENTRAL ILLINOIS. DID FOLLOW HRRR TRENDS
FOR PRECIP TIMING/COVERAGE AND INTENSITY WITH THE 18Z PACKAGE. THERE
IS STILL A BIG QUESTION MARK SURROUNDING THE CIG FORECAST THIS
EVENING. WITH THE EXPECTED RAINS...AND FLOW OFF OF THE
LAKE...GUIDANCE DID BRING CIGS DOWN TO A CAT 2 AND INTO THE IFR
REALM...BUT WITH THE LACK OF PRECIP...WOULD ONLY EXPECT CIGS TO
FALL INTO THE LOWER MVFR CATEGORY...AND STAY OUT OF LIFR/IFR.
WINDS WILL REMAIN OUT OF THE NORTH AS THE LOW MOVES EAST...AND
EXPECT SOME DAYTIME GUSTS INTO THE LOWER 20S THURSDAY AFTERNOON.
SHEA
//ORD AND MDW CONFIDENCE...UPDATED 18Z...
* MODERATE/HIGH CONFIDENCE ON THE PRECIP TRENDS
* MODERATE CONFIDENCE ON THE WIND FORECAST
* LOW CONFIDENCE ON THE CIG HEIGHT FORECAST
SHEA
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
THURSDAY NIGHT...VFR.
FRIDAY...CHANCE SHRA. SLIGHT CHANCE TSRA OVERNIGHT. OCNL MVFR
CIGS/VIS POSSIBLE.
SATURDAY...MVFR. CHANCE SHRA.
SUNDAY...VFR. WX NIL.
MONDAY...VFR. WX NIL.
TUESDAY...CHANCE AFTERNOON TSRA.
LENNING
&&
.MARINE...
303 AM CDT
LOW PRESSURE CROSSING ILLINOIS LATE TODAY AND MOVING INTO OHIO BY
TOMORROW WILL SUPPORT EASTERLY FLOW OVER LAKE MICHIGAN THROUGH THE
DAY...TURNING NORTH BEHIND THE LOW OVERNIGHT AND TOMORROW. THE
LONG COLD NORTH FETCH TOMORROW WILL SUPPORT AMPLE WAVE GROWTH
ACROSS THE SOUTH HALF OF THE LAKE TOMORROW INTO FRIDAY. WINDS MAY
BE A BIT STRONGER THAN ADVERTISED THURSDAY...BUT SUSTAINED GALES
DO NOT APPEAR LIKELY AT THIS TIME. THE RETURN TO EASTERLY FLOW BY
LATE FRIDAY THEN APPEARS TO PERSIST THROUGH THE WEEKEND ALONG THE
EDGE OF A BROAD HIGH PRESSURE AREA THAT WILL VERY GRADUALLY MOVE
EAST THROUGH THE GREAT LAKES.
LENNING
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
552 PM EDT WED APR 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 145 PM EDT WED APR 25 2012
LOW PRESSURE TRAVELING THROUGH THE OHIO VALLEY TONIGHT WILL BE
REPLACED BY HIGH PRESSURE THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL MOVE THROUGH THE OHIO VALLEY FRIDAY INTO SATURDAY. HIGH
PRESSURE SHOULD CONTROL INDIANA WEATHER FOR SEVERAL DAYS AFTER THAT.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 145 PM EDT WED APR 25 2012
FORECAST ISSUE IS POPS.
DETERMINISTIC FIELDS NOT TOO DIFFERENT...BUT MAV QUITE A BIT
WETTER THAN MET. PCPN GRADUALLY SEEMS TO BE FILLING IN AHEAD OF
LOW THAT ALL MODELS HAVE CROSSING AREA OVERNIGHT. RUC SHOWS RAIN
EVERYWHERE IN CWA 00Z-03Z. ALL THIS MAKES ME LIKE THE MAV A LOT
BETTER. IN FACT WILL BE NO LOWER THAN LIKELY ANYWHERE AND
CATEGORICAL ABOUT EASTERN TWO THIRDS.
MAV AND MET NOT TOO DIFFERENT ON LOWS...WHICH WILL BE TRICKY WITH
FRONT. OFTEN CONSENSUS WORKS WELL IN SUCH CASES AND WILL TRY THAT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 145 PM EDT WED APR 25 2012
MOST IMPORTANT ISSUE CHANCE OF RAIN FROM FRIDAY INTO SATURDAY.
EVERYTHING POINTS TO DRY BY 12Z TOMORROW AND INTO FRIDAY. WITH
CYCLONIC CURVATURE PART OF TOMORROW AND CU RULE PRETTY NEGATIVE
MOSTLY CLOUDY UNTIL AFTERNOON. WITH DRY AIR AND HIGH PRESSURE
MOSTLY CLEAR TOMORROW NIGHT.
FRIDAY NAM AND GFS START TO DIFFER SIGNIFICANTLY. GFS MUCH BETTER
SUPPORTED BY NON AMERICAN MODELS...AND IS OFTEN MORE ROBUST THAN
NAM FOR THAT FAR OUT. WILL ACCEPT THAT MODEL AND ITS RELATIVELY
HIGH POPS.
THINKING IN TERMS OF CLOUDS...MET TEMPS FOR TOMORROW. OTHERWISE
MAINLY MAV TEMPS SINCE LIKE PARENT MODEL BETTER.
MAXS SATURDAY DIFFICULT..DEPENDENT ON EXACT LOCATION OF BOUNDARY
OVER CWA. ILN MADE GOOD CASE FOR GUIDANCE BEING MUCH TOO
WARM. WE SHOULD BE A BIT WARMER SINCE WILL HAVE BETTER SHOT AT
SOME SUN THAN THEY DO. WILL TRY LOWER ENSEMBLE MOS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
ISSUED AT 239 PM EDT WED APR 25 2012
COOL START TO THE PERIOD AS THE WEEKEND LOOKS WET AND COOL AS
SURFACE RIDGING WILL BE CENTERED OVER THE NORTHERN GREAT LAKES AND
MOVING INTO SOUTHEAST ONTARIO/SOUTHWEST QUEBEC. THIS WILL LEAVE
AND ELY SURFACE FLOW WITH CLOUDS ON SATURDAY AND SUNDAY WITH THE
BETTER CHANCE FOR RAIN SATURDAY.
BOTH THE GFS AND THE EURO ARE INDICATING LOW PRESSURE SETTING UP
IN THE CENTRAL PLAINS TO START THE WEEK BRINGING BACK SOURLY FLOW
AND ABOVE NORMAL TEMPERATURES BY TUESDAY. STILL A QUESTION LATER
IN THE PERIOD ON WEDNESDAY WHEN PRECIPITATION WILL RETURN...BUT IT
LOOKS LIKE A CHANCE OF RAIN OR THUNDERSTORMS LATE TUESDAY OR
WEDNESDAY.
&&
.AVIATION /DISCUSSION FOR 26/00Z TAF ISSUANCE/...
ISSUED AT 552 PM EDT WED APR 25 2012
A WARM FRONT FROM AROUND BMG TO HUF AT 22Z WILL LIFT JUST NORTHEAST
OF IND AFTER 03Z AS A WAVE OF LOW PRESSURE ACROSS NORTHWEST ILLINOIS
DROPS SOUTHEAST ALONG THE FRONT. FINALLY...AN ASSOCIATED COLD FRONT
WILL DROP SOUTHEAST OF BMG AFTER 08Z TONIGHT. WITH STRONG SHEAR AND
SOME INSTABILITY...THUNDERSTORMS ARE EXPECTED TO BREAK OUT
ESPECIALLY AFTER 03Z BEFORE ENDING AFTER 08Z FROM NORTHWEST TO
SOUTHEAST. MOSTLY VFR CONDITIONS WILL BECOME MVFR OR WORSE OVERNIGHT
AS LOW LEVEL MOISTURE INCREASES. CONDITIONS WILL IMPROVE TO VFR
AFTER 16Z AS HIGH PRESSURE BUILDS IN FROM THE MISSISSIPPI VALLEY.
WILL GO WITH VCTS AND CB GROUPS TO START OFF AND QUICKY TRANSITION
TO TEMPO TS AFTER 01Z AS THE COLD FRONT GETS CLOSER.
WINDS WILL BE SOUTHEAST AHEAD OF THE WARM FRONT 10 KNOTS OR LESS AND
SHIFT TO SOUTH IN THE WARM SECTOR. COULD SEE MUCH HIGH WINDS IN
THUNDERSTORMS...AND MAY NEED TO ADD THEM AT ISSUANCE TIME. WINDS
WILL FINALLY SHIFT TO SOUTHWEST AND THE NORTHWEST BEHIND THE COLD
FRONT THAT SHOULD REACH BMG AROUND 08Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....MCCARTHY
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
420 PM EDT WED APR 25 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 145 PM EDT WED APR 25 2012
LOW PRESSURE TRAVELING THROUGH THE OHIO VALLEY TONIGHT WILL BE
REPLACED BY HIGH PRESSURE THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL MOVE THROUGH THE OHIO VALLEY FRIDAY INTO SATURDAY. HIGH
PRESSURE SHOULD CONTROL INDIANA WEATHER FOR SEVERAL DAYS AFTER THAT.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 145 PM EDT WED APR 25 2012
FORECAST ISSUE IS POPS.
DETERMINISTIC FIELDS NOT TOO DIFFERENT...BUT MAV QUITE A BIT
WETTER THAN MET. PCPN GRADUALLY SEEMS TO BE FILLING IN AHEAD OF
LOW THAT ALL MODELS HAVE CROSSING AREA OVERNIGHT. RUC SHOWS RAIN
EVERYWHERE IN CWA 00Z-03Z. ALL THIS MAKES ME LIKE THE MAV A LOT
BETTER. IN FACT WILL BE NO LOWER THAN LIKELY ANYWHERE AND
CATEGORICAL ABOUT EASTERN TWO THIRDS.
MAV AND MET NOT TOO DIFFERENT ON LOWS...WHICH WILL BE TRICKY WITH
FRONT. OFTEN CONSENSUS WORKS WELL IN SUCH CASES AND WILL TRY THAT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 145 PM EDT WED APR 25 2012
MOST IMPORTANT ISSUE CHANCE OF RAIN FROM FRIDAY INTO SATURDAY.
EVERYTHING POINTS TO DRY BY 12Z TOMORROW AND INTO FRIDAY. WITH
CYCLONIC CURVATURE PART OF TOMORROW AND CU RULE PRETTY NEGATIVE
MOSTLY CLOUDY UNTIL AFTERNOON. WITH DRY AIR AND HIGH PRESSURE
MOSTLY CLEAR TOMORROW NIGHT.
FRIDAY NAM AND GFS START TO DIFFER SIGNIFICANTLY. GFS MUCH BETTER
SUPPORTED BY NON AMERICAN MODELS...AND IS OFTEN MORE ROBUST THAN
NAM FOR THAT FAR OUT. WILL ACCEPT THAT MODEL AND ITS RELATIVELY
HIGH POPS.
THINKING IN TERMS OF CLOUDS...MET TEMPS FOR TOMORROW. OTHERWISE
MAINLY MAV TEMPS SINCE LIKE PARENT MODEL BETTER.
MAXS SATURDAY DIFFICULT..DEPENDENT ON EXACT LOCATION OF BOUNDARY
OVER CWA. ILN MADE GOOD CASE FOR GUIDANCE BEING MUCH TOO
WARM. WE SHOULD BE A BIT WARMER SINCE WILL HAVE BETTER SHOT AT
SOME SUN THAN THEY DO. WILL TRY LOWER ENSEMBLE MOS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
ISSUED AT 239 PM EDT WED APR 25 2012
COOL START TO THE PERIOD AS THE WEEKEND LOOKS WET AND COOL AS
SURFACE RIDGING WILL BE CENTERED OVER THE NORTHERN GREAT LAKES AND
MOVING INTO SOUTHEAST ONTARIO/SOUTHWEST QUEBEC. THIS WILL LEAVE
AND ELY SURFACE FLOW WITH CLOUDS ON SATURDAY AND SUNDAY WITH THE
BETTER CHANCE FOR RAIN SATURDAY.
BOTH THE GFS AND THE EURO ARE INDICATING LOW PRESSURE SETTING UP
IN THE CENTRAL PLAINS TO START THE WEEK BRINGING BACK SOURLY FLOW
AND ABOVE NORMAL TEMPERATURES BY TUESDAY. STILL A QUESTION LATER
IN THE PERIOD ON WEDNESDAY WHEN PRECIPITATION WILL RETURN...BUT IT
LOOKS LIKE A CHANCE OF RAIN OR THUNDERSTORMS LATE TUESDAY OR
WEDNESDAY.
&&
.AVIATION /DISCUSSION FOR 25/21Z TAF UPDATES/...
ISSUED AT 420 PM EDT WED APR 25 2012
HAD TO ADD TEMPO TS TO THE HUF AND LAF TAFS THROUGH 22Z BASED ON
RADAR AND LIGHTNING TRENDS AND VCSH TO IND AND BMG.
OTHERWISE...ADJUSTED WINDS MORE SOUTHERLY BASED ON OBSERVATIONAL
TRENDS.
PREVIOUS DISCUSSION FOLLOWS...
VFR CONDITIONS CONTINUE FOR NOW. LOW PRESSURE OVER IA IS FORECAST
TO MOVE SOUTHEAST ACROSS IL THEN EASTWARD INTO SOUTHWEST OH BY
THURSDAY MORNING. WARM FRONT CURRENTLY EXTENDS SOUTHEASTWARD FROM
NEAR KDVN TO JUST NORTHEAST OF KEVV AND IS EXPECTED TO BE FOCUS OF
THUNDERSTORM DEVELOPMENT AHEAD OF THE LOW THIS EVENING AND
TONIGHT.
LOOKS LIKE THERE WILL BE A THREAT FOR SOME HI BASED THUNDERSTORMS
THIS EVENING NORTHEAST OF THE WARM FRONT...THEN WHEN THE LOW MOVES
INTO IL AND IN...MORE WIDESPREAD SURFACE BASED ACTIVITY IS EXPECTED
AFTER 25/21Z AROUND KHUF AND OTHER AREAS AFTER 26/00Z. EXPECT MOSTLY
MVFR CONDITIONS AFTER 26/21Z OCCASIONALLY DROPPING BELOW MVFR IN THE
VICINITY OF THUNDERSTORMS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....MCCARTHY
AVIATION...MCCARTHY/MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
256 PM EDT WED APR 25 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 145 PM EDT WED APR 25 2012
LOW PRESSURE TRAVELING THROUGH THE OHIO VALLEY TONIGHT WILL BE
REPLACED BY HIGH PRESSURE THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL MOVE THROUGH THE OHIO VALLEY FRIDAY INTO SATURDAY. HIGH
PRESSURE SHOULD CONTROL INDIANA WEATHER FOR SEVERAL DAYS AFTER THAT.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 145 PM EDT WED APR 25 2012
FORECAST ISSUE IS POPS.
DETERMINISTIC FIELDS NOT TOO DIFFERENT...BUT MAV QUITE A BIT
WETTER THAN MET. PCPN GRADUALLY SEEMS TO BE FILLING IN AHEAD OF
LOW THAT ALL MODELS HAVE CROSSING AREA OVERNIGHT. RUC SHOWS RAIN
EVERYWHERE IN CWA 00Z-03Z. ALL THIS MAKES ME LIKE THE MAV A LOT
BETTER. IN FACT WILL BE NO LOWER THAN LIKELY ANYWHERE AND
CATEGORICAL ABOUT EASTERN TWO THIRDS.
MAV AND MET NOT TOO DIFFERENT ON LOWS...WHICH WILL BE TRICKY WITH
FRONT. OFTEN CONSENSUS WORKS WELL IN SUCH CASES AND WILL TRY THAT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 145 PM EDT WED APR 25 2012
MOST IMPORTANT ISSUE CHANCE OF RAIN FROM FRIDAY INTO SATURDAY.
EVERYTHING POINTS TO DRY BY 12Z TOMORROW AND INTO FRIDAY. WITH
CYCLONIC CURVATURE PART OF TOMORROW AND CU RULE PRETTY NEGATIVE
MOSTLY CLOUDY UNTIL AFTERNOON. WITH DRY AIR AND HIGH PRESSURE
MOSTLY CLEAR TOMORROW NIGHT.
FRIDAY NAM AND GFS START TO DIFFER SIGNIFICANTLY. GFS MUCH BETTER
SUPPORTED BY NON AMERICAN MODELS...AND IS OFTEN MORE ROBUST THAN
NAM FOR THAT FAR OUT. WILL ACCEPT THAT MODEL AND ITS RELATIVELY
HIGH POPS.
THINKING IN TERMS OF CLOUDS...MET TEMPS FOR TOMORROW. OTHERWISE
MAINLY MAV TEMPS SINCE LIKE PARENT MODEL BETTER.
MAXS SATURDAY DIFFICULT..DEPENDENT ON EXACT LOCATION OF BOUNDARY
OVER CWA. ILN MADE GOOD CASE FOR GUIDANCE BEING MUCH TOO
WARM. WE SHOULD BE A BIT WARMER SINCE WILL HAVE BETTER SHOT AT
SOME SUN THAN THEY DO. WILL TRY LOWER ENSEMBLE MOS.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
ISSUED AT 239 PM EDT WED APR 25 2012
COOL START TO THE PERIOD AS THE WEEKEND LOOKS WET AND COOL AS
SURFACE RIDGING WILL BE CENTERED OVER THE NORTHERN GREAT LAKES AND
MOVING INTO SOUTHEAST ONTARIO/SOUTHWEST QUEBEC. THIS WILL LEAVE
AND ELY SURFACE FLOW WITH CLOUDS ON SATURDAY AND SUNDAY WITH THE
BETTER CHANCE FOR RAIN SATURDAY.
BOTH THE GFS AND THE EURO ARE INDICATING LOW PRESSURE SETTING UP
IN THE CENTRAL PLAINS TO START THE WEEK BRINGING BACK SOURLY FLOW
AND ABOVE NORMAL TEMPERATURES BY TUESDAY. STILL A QUESTION LATER
IN THE PERIOD ON WEDNESDAY WHEN PRECIPITATION WILL RETURN...BUT IT
LOOKS LIKE A CHANCE OF RAIN OR THUNDERSTORMS LATE TUESDAY OR WEDNESDAY.
&&
.AVIATION /DISCUSSION FOR 25/18Z TAFS/...
ISSUED AT 1212 PM EDT WED APR 25 2012
VFR CONDITIONS CONTINUE FOR NOW. LOW PRESSURE OVER IA IS FORECAST
TO MOVE SOUTHEAST ACROSS IL THEN EASTWARD INTO SOUTHWEST OH BY
THURSDAY MORNING. WARM FRONT CURRENTLY EXTENDS SOUTHEASTWARD FROM
NEAR KDVN TO JUST NORTHEAST OF KEVV AND IS EXPECTED TO BE FOCUS OF
THUNDERSTORM DEVELOPMENT AHEAD OF THE LOW THIS EVENING AND
TONIGHT.
LOOKS LIKE THERE WILL BE A THREAT FOR SOME HI BASED THUNDERSTORMS
THIS EVENING NORTHEAST OF THE WARM FRONT...THEN WHEN THE LOW MOVES
INTO IL AND IN...MORE WIDESPREAD SURFACE BASED ACTIVITY IS
EXPECTED AFTER 25/21Z AROUND KHUF AND OTHER AREAS AFTER 26/00Z. EXPECT
MOSTLY MVFR CONDITIONS AFTER 26/21Z OCCASIONALLY DROPPING BELOW
MVFR IN THE VICINITY OF THUNDERSTORMS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....MCCARTHY
AVIATION...MCCARTHY
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
146 PM EDT WED APR 25 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 145 PM EDT WED APR 25 2012
LOW PRESSURE TRAVELING THROUGH THE OHIO VALLEY TONIGHT WILL BE
REPLACED BY HIGH PRESSURE THURSDAY. ANOTHER LOW PRESSURE SYSTEM
WILL MOVE THROUGH THE OHIO VALLEY FRIDAY INTO SATURDAY. HIGH
PRESSURE SHOULD CONTROL INDIANA WEATHER FOR SEVERAL DAYS AFTER THAT.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 145 PM EDT WED APR 25 2012
FORECAST ISSUE IS POPS.
DETERMINISTIC FIELDS NOT TOO DIFFERENT...BUT MAV QUITE A BIT
WETTER THAN MET. PCPN GRADUALLY SEEMS TO BE FILLING IN AHEAD OF
LOW THAT ALL MODELS HAVE CROSSING AREA OVERNIGHT. RUC SHOWS RAIN
EVERYWHERE IN CWA 00Z-03Z. ALL THIS MAKES ME LIKE THE MAV A LOT
BETTER. IN FACT WILL BE NO LOWER THAN LIKELY ANYWHERE AND
CATEGORICAL ABOUT EASTERN TWO THIRDS.
MAV AND MET NOT TOO DIFFERENT ON LOWS...WHICH WILL BE TRICKY WITH
FRONT. OFTEN CONSENSUS WORKS WELL IN SUCH CASES AND WILL TRY THAT.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
ISSUED AT 145 PM EDT WED APR 25 2012
MOST IMPORTANT ISSUE CHANCE OF RAIN FROM FRIDAY INTO SATURDAY.
EVERYTHING POINTS TO DRY BY 12Z TOMORROW AND INTO FRIDAY. WITH
CYCLONIC CURVATURE PART OF TOMORROW AND CU RULE PRETTY NEGATIVE
MOSTLY CLOUDY UNTIL AFTERNOON. WITH DRY AIR AND HIGH PRESSURE
MOSTLY CLEAR TOMORROW NIGHT.
FRIDAY NAM AND GFS START TO DIFFER SIGNIFICANTLY. GFS MUCH BETTER
SUPPORTED BY NON AMERICAN MODELS...AND IS OFTEN MORE ROBUST THAN
NAM FOR THAT FAR OUT. WILL ACCEPT THAT MODEL AND ITS RELATIVELY
HIGH POPS.
THINKING IN TERMS OF CLOUDS...MET TEMPS FOR TOMORROW. OTHERWISE
MAINLY MAV TEMPS SINCE LIKE PARENT MODEL BETTER.
MAXS SATURDAY DIFFICULT..DEPENDENT ON EXACT LOCATION OF BOUNDARY
OVER CWA. ILN MADE GOOD CASE FOR GUIDANCE BEING MUCH TOO
WARM. WE SHOULD BE A BIT WARMER SINCE WILL HAVE BETTER SHOT AT
SOME SUN THAN THEY DO. WILL TRY LOWER ENSEMBLE MOS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 324 AM EDT WED APR 25 2012
THE GFS HAS COME INTO AGREEMENT WITH THE MORE PROGRESSIVE EURO IN
REGARD TO THIS WEEKEND/S PRECIP EVENT...AND THE LATEST
INITIALIZATION IS ALSO SHOWING PRECIP ENDING BY SUNDAY
MORNING...WITH THE BEST CHANCES AT THE BEGINNING OF THE WEEKEND.
SO...LIKELY POPS ON SATURDAY SEEM REASONABLE...AND EXPECT THOSE TO
INCREASE TO CATEGORICAL OVER THE NEXT SEVERAL DAYS.
BRIEF RIDGING WILL BRING DRIER CONDITIONS LATE SUNDAY THROUGH
MONDAY. HOWEVER...ANOTHER SYSTEM WILL MOVE THROUGH CANADA...AND ITS
ASSOCIATED COLD FRONT WILL TRACK ACROSS CENTRAL INDIANA ON TUESDAY
AND WEDNESDAY BRINGING THE NEXT ROUND OF SHOWERS AND THUNDERSTORMS.
&&
.AVIATION /DISCUSSION FOR 25/18Z TAFS/...
ISSUED AT 1212 PM EDT WED APR 25 2012
VFR CONDITIONS CONTINUE FOR NOW. LOW PRESSURE OVER IA IS FORECAST
TO MOVE SOUTHEAST ACROSS IL THEN EASTWARD INTO SOUTHWEST OH BY
THURSDAY MORNING. WARM FRONT CURRENTLY EXTENDS SOUTHEASTWARD FROM
NEAR KDVN TO JUST NORTHEAST OF KEVV AND IS EXPECTED TO BE FOCUS OF
THUNDERSTORM DEVELOPMENT AHEAD OF THE LOW THIS EVENING AND
TONIGHT.
LOOKS LIKE THERE WILL BE A THREAT FOR SOME HI BASED THUNDERSTORMS
THIS EVENING NORTHEAST OF THE WARM FRONT...THEN WHEN THE LOW MOVES
INTO IL AND IN...MORE WIDESPREAD SURFACE BASED ACTIVITY IS
EXPECTED AFTER 25/21Z AROUND KHUF AND OTHER AREAS AFTER 26/00Z. EXPECT
MOSTLY MVFR CONDITIONS AFTER 26/21Z OCCASIONALLY DROPPING BELOW
MVFR IN THE VICINITY OF THUNDERSTORMS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....TDUD
AVIATION...MCCARTHY
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
452 PM EDT WED APR 25 2012
.UPDATE...
ISSUED AT 449 PM EDT WED APR 25 2012
TIMING OF CONVECTION APPROACHING FROM THE WEST AND FURTHER CONVECTION
ANTICIPATED LATER THIS EVENING AS WELL AS ASSOCIATED SKY COVER WAS
ADJUSTED BASED ON THE LATEST SAT AND RADAR TRENDS. OVERALL...THE 18Z
NAM HAS A DECENT HANDLE ON THE APPROACHING CONVECTION...BUT APPEARS
TO BE A BIT TOO SLOW. CONVECTION OVER THE NEXT 2 HOURS OR SO SHOULD
GENERALLY BE OVER THE SW CWA AND THEN PROBABLY BECOME FOCUS MORE TO
THE NE CLOSER TO THE WARM FRONT AND GREATER THETA AND DEWPOINT
GRADIENTS AS THE EVENING WEARS ON. CONVECTION THIS EVENING OR EARLY
TONIGHT IS STILL CAPABLE OF PRODUCING SOME HAIL OR STRONG WIND GUSTS.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 325 PM EDT WED APR 25 2012
A WARM FRONT CONTINUES TO GRADUALLY LIFT NE ACROSS THE CWA AND APPEARS
TO BE ABOUT TWO THIRDS ACROSS THE CWA AS OF 3 PM.
AS OF MID AFTERNOON...A RIDGE OF HIGH PRESSURE REMAINS OVER
MEXICO...AND EXTENDS NORTH INTO THE ROCKIES AND SOUTHERN PLAINS. WNW
FLOW ALOFT CONTINUES BETWEEN THIS RIDGING AND A TROUGH MOVING OFF
THE EASTERN SEABOARD. THERE APPEAR TO BE AT LEAST TWO DISTURBANCES
UPSTREAM...ONE ACROSS IA/MO AND ANOTHER OVER THE DAKOTAS. AT THE
SURFACE...AN AREA OF LOW PRESSURE AS OVER IA WITH THE WARM FRONT
EXTENDING SE INTO THE COMMONWEALTH AND THEN ON OFF THE CAROLINA
COAST. THERE ALSO APPEARS BE ANOTHER SFC TROUGH OR AREA OF THETA
GRADIENT NEAR THE CURRENT CONVECTION OVER SOUTHERN IN AND WEST CENTRAL
KY.
OVER THE NEXT COUPLE OF DAYS...THE RIDGE AXIS WILL BEGIN TO SHIFT
EAST AS TROUGHING WORKS INTO THE WESTERN US WITH TROUGHING REMAINING
OVER THE NORTHEASTERN US. FLAT OR LOW AMPLITUDE RIDGING IS EXPECTED
TO BUILD EAST ACROSS THE GULF COAST STATES. THE LOW IS EXPECTED TO
REACH WEST CENTRAL IL THIS EVENING AND THEN TRACK EAST ACROSS THE OH
VALLEY. THIS WILL SEND THE WARM FRONT ACROSS MOST OF THE REGION
THROUGH THIS EVENING...BUT THE BOUNDARY MAY NOT REACH THE WV BORDER
UNTIL OVERNIGHT. THEN AS THE LOW PASSES BY...THE COLD FRONT WILL DROP
SOUTH ACROSS THE COMMONWEALTH VERY LATE TONIGHT AND THROUGH THE DAY ON
THURSDAY. THIS BOUNDARY SHOULD THEN BEGIN TO STALL OUT OF THE TN
VALLEY REGION. SFC HIGH PRESSURE SHOULD BEGIN TO BUILD DOWN TOWARD
THE CWA FROM LATE ON THU INTO THU NIGHT.
THE EXACT EVOLUTION OF CONVECTION OVER THE NEXT FEW HOURS IS
GENERALLY LOW CONFIDENCE. THE 12Z NAM DOES NOT APPEAR TO BE TOO BAD
WITH PLACEMENT OF CONVECTION OVER WEST CENTRAL KY AT PRESENT. THIS
MODEL AND SOME OF THE RECENT HRRR RUNS AS WELL AS THE SREF POINT TO
CONVECTION ALSO DEVELOPING FURTHER NE NEAR THE WARM FRONT...POSSIBLY
ACROSS THE CENTRAL PORTION OF THE CWA...BETWEEN ABOUT 21Z AND 0Z AS
THE FIRST OF THE ABOVE MENTIONED SHORTWAVES APPROACHES THE AREA.
SOME OF THE MODELS TAKE THE CONVECTION TO OUR WEST TOWARD THE SW CWA.
ADDITIONAL CONVECTION SHOULD THEN DEVELOP IN THE VICINITY OF THE WARM
FRONT AND POSSIBLY EVOLVE INTO AN MCS WITH POSSIBLY BOWING SEGMENTS
SOMETIME DURING THE 3Z TO 9Z TIMEFRAME. AN INCREASING LOW LEVEL JET
AS THE SFC LOW APPROACHES WILL LEAD TO INCREASING SHEAR AND STRONGER
WINDS ALOFT. TIME OF DAY...GENERALLY LATE EVENING INTO THE OVERNIGHT
IS NOT USUALLY FAVORABLE FOR SEVERE CONVECTION AND IT MAY TEND TO
WEAKEN OR BE LARGELY ELEVATED AS IT MOVES INTO OR DEVELOPS OVER THE
CWA LATE IN THE EVENING OR OVERNIGHT. HOWEVER...SOME HAIL...POSSIBLY
LARGE...AS WELL AS GUSTY WINDS CANNOT BE RULED OUT. MOS GUIDANCE AS
WELL AS RECENT MODEL GUIDANCE AND SREF INDICATE THE HIGHER
PROBABILITIES FOR CONVECTION ACROSS THE NORTH AND NORTHEASTERN
CWA...BUT ENOUGH INSTABILITY SHOULD BE PRESENT FOR GOOD COVERAGE OF
CONVECTION EVEN AS FAR SOUTH AS THE TN LINE IN ADVANCE OF THE COLD
FRONT AS THE SECOND SHORTWAVE APPROACHES. OVERALL...INCREASED POPS A
LITTLE BIT MORE TONIGHT. MIN T TONIGHT WILL BE LIMITED DUE TO THE
ANTICIPATED CLOUD COVER AND PRECIP ACROSS THE AREA.
IN THE WAKE OF CONVECTION TONIGHT...THE SURFACE COLD FRONT SHOULD
GRADUALLY DROP SOUTH ON THU. SOME REDEVELOPMENT OF CONVECTION SHOULD
OCCUR ALONG AND IN ADVANCE OF THE FRONT BY MIDDAY TO EARLY AFTERNOON.
AT THIS POINT...IT DOES APPEAR THAT THE FRONT SHOULD DROP SOUTH OF
THE AREA ON THU NIGHT WITH AT LEAST SOME PARTIAL CLEARING ACROSS MOST
OF THE AREA...AND CONSIDERABLE CLEARING IN THE NORTH. AHEAD OF THE
BOUNDARY...MAX T SHOULD AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. COLD
ADVECTION AROUND THE HIGH AND MORE IN THE WAY OF CLEARING THERE
SHOULD LEAD TO A NORTH TO SOUTH GRADIENT IN MIN T ON THU NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 PM EDT WED APR 25 2012
MODELS SHOW GOOD AGREEMENT WITH HAVING AMPLIFIED MID/UPPER LEVELS
BECOMING MORE DAMPENED BY EARLY NEXT WEEK. MODELS SHOWING A LITTLE
BETTER AGREEMENT WITH THE DETAILS FROM FRIDAY THROUGH SATURDAY...BUT
STILL HAVE SOME CONSIDERABLE DIFFERENCES FOR THE SECOND HALF OF THE
WEEKEND AND BEYOND.
THE PERIOD WILL START WITH THE FRONTAL BOUNDARY TO OUR
SOUTH...LEAVING EASTERN KENTUCKY HIGH AND DRY EARLY FRIDAY.
HOWEVER...A SHORTWAVE PUSHING NORTHEAST ACROSS THE MID MISSISSIPPI
REGION WILL HELP BRING THE FRONT BACK TO THE NORTH DURING THE DAY
FRIDAY AND FRIDAY NIGHT. A WEAK DISTURBANCE WILL LIKELY SLIDE
SOUTHEAST ALONG THE FRONT EARLY FRIDAY...WHICH MAY KEEP THE BOUNDARY
ACTIVE THROUGH EARLY AFTERNOON. THIS MEANS...THE BEST THREAT FOR
SHOWERS AND STORMS WILL BE ACROSS THE SOUTH EARLY ON. BY MID TO LATE
AFTERNOON...LACK OF FORCING ALONG THE FRONTAL ZONE...WILL LIKELY
KEEP THINGS DRY...BUT WE COULD SQUEEZE OUT AN ISOLATED SHOWER OR
STORM ALONG THE FRONT. FRIDAY NIGHT...THE BOUNDARY WILL CONTINUE TO
LIFT TO OUR NORTH...AND STILL CANNOT RULE OUT AN ISOLATED SHOWER OR
STORM...BUT ALL OF THE BETTER FORCING WILL BE WELL TO OUR NORTHWEST
DURING THIS TIME...SO NO NEED TO GO HIGHER THAN SLIGHT CHANCE AT
THIS TIME. BY SATURDAY MORNING...WE MAY NEED TO WATCH A POTENTIAL
MCS ACROSS THE OHIO VALLEY AS IT COULD BRUSH THE NORTHERN HALF OF
KENTUCKY. THUS...BROUGHT IN SOME BETTER POPS SATURDAY MORNING INTO
EARLY AFTERNOON. REALLY TOUGH TO NAIL DOWN WHERE THE FRONT WILL WIND
UP BY THE TIME THIS MCS ACTIVITY DEPARTS BY SATURDAY AFTERNOON...BUT
IT WILL LIKELY LIE ACROSS OUR REGION...LEADING TO CONTINUED CHANCES
FOR UNSETTLED WEATHER THROUGH THE REST OF THE WEEKEND AND PERHAPS
EVEN INTO EARLY NEXT WEEK. GOING TO KEEP POPS IN THE CHANCE CATEGORY
FOR THIS TIME PERIOD GIVEN LACK OF CERTAINTY IN THE FORECAST. THINGS
MAY EVENTUALLY DRY OUT...BUT CONFIDENCE IS NOT HIGH ON WHEN OR EVEN
IF THIS WILL HAPPEN. WITH A FLATTER MID LEVELS...A MORE PROGRESSIVE
PATTERN MAY SET UP LEADING TO MORE FREQUENT SHORTWAVES AND CHANCES
FOR RAIN. THUS...REALLY TOUGH TO GO DRY IN ANY EXTENDED PERIOD AT
THIS TIME. AS FAR AS TEMPERATURES...WILL BRING IN A BETTER GRADIENT
FOR FRIDAY INTO SATURDAY...AND KEEP THINGS MORE IN LINE WITH
GUIDANCE BEYOND THAT WITH VERY UNCERTAIN PLACEMENT OF THE BOUNDARY.
A SHARP NORTH/SOUTH GRADIENT WILL LIKELY EXIST INTO NEXT WEEK WITH
THIS BOUNDARY AROUND OUR REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 206 PM EDT WED APR 25 2012
A FEW VFR CU SHOULD DEVELOP AT LEAST AT JKL EARLY IN THE PERIOD...
AND THERE IS A SMALL POTENTIAL FOR A SHOWER OR THUNDERSTORM DEVELOPING
AFTER 21Z IN ALL AREAS...BUT THEY WILL BE MORE LIKELY TO HOLD OFF
UNTIL AFTER 0Z. THE GREATEST PROBABILITY FOR CONVECTION STILL APPEARS
TO BE FROM ABOUT 03Z-09Z...ESPECIALLY ALONG AND NORTH OF A KLEX TO
KJKL TO KLNP LINE. THESE COULD EVENTUALLY BRIEFLY BRING CONDITIONS
AS LOW AS IFR ALONG WITH GUSTY WINDS AND PERHAPS SOME HAIL OR HAIL
ALOFT. ENOUGH SATURATION SHOULD OCCUR NEARER TO THE COLD FRONT THAT
WILL DROP INTO THE AREA TONIGHT THAT AFTER THE 6Z TIMEFRAME...SOME
PREVAILING MVFR SHOULD DEVELOP AND PERSIST FOR MOST OF...IF NOT THE
ENTIRE REMAINDER OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...JP
LONG TERM....KAS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS JACKSON KY
347 PM EDT WED APR 25 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 325 PM EDT WED APR 25 2012
A WARM FRONT CONTINUES TO GRADUALLY LIFT NE ACROSS THE CWA AND APPEARS
TO BE ABOUT TWO THIRDS ACROSS THE CWA AS OF 3 PM.
AS OF MID AFTERNOON...A RIDGE OF HIGH PRESSURE REMAINS OVER
MEXICO...AND EXTENDS NORTH INTO THE ROCKIES AND SOUTHERN PLAINS. WNW
FLOW ALOFT CONTINUES BETWEEN THIS RIDGING AND A TROUGH MOVING OFF
THE EASTERN SEABOARD. THERE APPEAR TO BE AT LEAST TWO DISTURBANCES
UPSTREAM...ONE ACROSS IA/MO AND ANOTHER OVER THE DAKOTAS. AT THE
SURFACE...AN AREA OF LOW PRESSURE AS OVER IA WITH THE WARM FRONT
EXTENDING SE INTO THE COMMONWEALTH AND THEN ON OFF THE CAROLINA
COAST. THERE ALSO APPEARS BE ANOTHER SFC TROUGH OR AREA OF THETA
GRADIENT NEAR THE CURRENT CONVECTION OVER SOUTHERN IN AND WEST CENTRAL
KY.
OVER THE NEXT COUPLE OF DAYS...THE RIDGE AXIS WILL BEGIN TO SHIFT
EAST AS TROUGHING WORKS INTO THE WESTERN US WITH TROUGHING REMAINING
OVER THE NORTHEASTERN US. FLAT OR LOW AMPLITUDE RIDGING IS EXPECTED
TO BUILD EAST ACROSS THE GULF COAST STATES. THE LOW IS EXPECTED TO
REACH WEST CENTRAL IL THIS EVENING AND THEN TRACK EAST ACROSS THE OH
VALLEY. THIS WILL SEND THE WARM FRONT ACROSS MOST OF THE REGION
THROUGH THIS EVENING...BUT THE BOUNDARY MAY NOT REACH THE WV BORDER
UNTIL OVERNIGHT. THEN AS THE LOW PASSES BY...THE COLD FRONT WILL DROP
SOUTH ACROSS THE COMMONWEALTH VERY LATE TONIGHT AND THROUGH THE DAY ON
THURSDAY. THIS BOUNDARY SHOULD THEN BEGIN TO STALL OUT OF THE TN
VALLEY REGION. SFC HIGH PRESSURE SHOULD BEGIN TO BUILD DOWN TOWARD
THE CWA FROM LATE ON THU INTO THU NIGHT.
THE EXACT EVOLUTION OF CONVECTION OVER THE NEXT FEW HOURS IS
GENERALLY LOW CONFIDENCE. THE 12Z NAM DOES NOT APPEAR TO BE TOO BAD
WITH PLACEMENT OF CONVECTION OVER WEST CENTRAL KY AT PRESENT. THIS
MODEL AND SOME OF THE RECENT HRRR RUNS AS WELL AS THE SREF POINT TO
CONVECTION ALSO DEVELOPING FURTHER NE NEAR THE WARM FRONT...POSSIBLY
ACROSS THE CENTRAL PORTION OF THE CWA...BETWEEN ABOUT 21Z AND 0Z AS
THE FIRST OF THE ABOVE MENTIONED SHORTWAVES APPROACHES THE AREA.
SOME OF THE MODELS TAKE THE CONVECTION TO OUR WEST TOWARD THE SW CWA.
ADDITIONAL CONVECTION SHOULD THEN DEVELOP IN THE VICINITY OF THE WARM
FRONT AND POSSIBLY EVOLVE INTO AN MCS WITH POSSIBLY BOWING SEGMENTS
SOMETIME DURING THE 3Z TO 9Z TIMEFRAME. AN INCREASING LOW LEVEL JET
AS THE SFC LOW APPROACHES WILL LEAD TO INCREASING SHEAR AND STRONGER
WINDS ALOFT. TIME OF DAY...GENERALLY LATE EVENING INTO THE OVERNIGHT
IS NOT USUALLY FAVORABLE FOR SEVERE CONVECTION AND IT MAY TEND TO
WEAKEN OR BE LARGELY ELEVATED AS IT MOVES INTO OR DEVELOPS OVER THE
CWA LATE IN THE EVENING OR OVERNIGHT. HOWEVER...SOME HAIL...POSSIBLY
LARGE...AS WELL AS GUSTY WINDS CANNOT BE RULED OUT. MOS GUIDANCE AS
WELL AS RECENT MODEL GUIDANCE AND SREF INDICATE THE HIGHER
PROBABILITIES FOR CONVECTION ACROSS THE NORTH AND NORTHEASTERN
CWA...BUT ENOUGH INSTABILITY SHOULD BE PRESENT FOR GOOD COVERAGE OF
CONVECTION EVEN AS FAR SOUTH AS THE TN LINE IN ADVANCE OF THE COLD
FRONT AS THE SECOND SHORTWAVE APPROACHES. OVERALL...INCREASED POPS A
LITTLE BIT MORE TONIGHT. MIN T TONIGHT WILL BE LIMITED DUE TO THE
ANTICIPATED CLOUD COVER AND PRECIP ACROSS THE AREA.
IN THE WAKE OF CONVECTION TONIGHT...THE SURFACE COLD FRONT SHOULD
GRADUALLY DROP SOUTH ON THU. SOME REDEVELOPMENT OF CONVECTION SHOULD
OCCUR ALONG AND IN ADVANCE OF THE FRONT BY MIDDAY TO EARLY AFTERNOON.
AT THIS POINT...IT DOES APPEAR THAT THE FRONT SHOULD DROP SOUTH OF
THE AREA ON THU NIGHT WITH AT LEAST SOME PARTIAL CLEARING ACROSS MOST
OF THE AREA...AND CONSIDERABLE CLEARING IN THE NORTH. AHEAD OF THE
BOUNDARY...MAX T SHOULD AVERAGE NEAR TO SLIGHTLY ABOVE NORMAL. COLD
ADVECTION AROUND THE HIGH AND MORE IN THE WAY OF CLEARING THERE
SHOULD LEAD TO A NORTH TO SOUTH GRADIENT IN MIN T ON THU NIGHT.
.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 325 PM EDT WED APR 25 2012
MODELS SHOW GOOD AGREEMENT WITH HAVING AMPLIFIED MID/UPPER LEVELS
BECOMING MORE DAMPENED BY EARLY NEXT WEEK. MODELS SHOWING A LITTLE
BETTER AGREEMENT WITH THE DETAILS FROM FRIDAY THROUGH SATURDAY...BUT
STILL HAVE SOME CONSIDERABLE DIFFERENCES FOR THE SECOND HALF OF THE
WEEKEND AND BEYOND.
THE PERIOD WILL START WITH THE FRONTAL BOUNDARY TO OUR
SOUTH...LEAVING EASTERN KENTUCKY HIGH AND DRY EARLY FRIDAY.
HOWEVER...A SHORTWAVE PUSHING NORTHEAST ACROSS THE MID MISSISSIPPI
REGION WILL HELP BRING THE FRONT BACK TO THE NORTH DURING THE DAY
FRIDAY AND FRIDAY NIGHT. A WEAK DISTURBANCE WILL LIKELY SLIDE
SOUTHEAST ALONG THE FRONT EARLY FRIDAY...WHICH MAY KEEP THE BOUNDARY
ACTIVE THROUGH EARLY AFTERNOON. THIS MEANS...THE BEST THREAT FOR
SHOWERS AND STORMS WILL BE ACROSS THE SOUTH EARLY ON. BY MID TO LATE
AFTERNOON...LACK OF FORCING ALONG THE FRONTAL ZONE...WILL LIKELY
KEEP THINGS DRY...BUT WE COULD SQUEEZE OUT AN ISOLATED SHOWER OR
STORM ALONG THE FRONT. FRIDAY NIGHT...THE BOUNDARY WILL CONTINUE TO
LIFT TO OUR NORTH...AND STILL CANNOT RULE OUT AN ISOLATED SHOWER OR
STORM...BUT ALL OF THE BETTER FORCING WILL BE WELL TO OUR NORTHWEST
DURING THIS TIME...SO NO NEED TO GO HIGHER THAN SLIGHT CHANCE AT
THIS TIME. BY SATURDAY MORNING...WE MAY NEED TO WATCH A POTENTIAL
MCS ACROSS THE OHIO VALLEY AS IT COULD BRUSH THE NORTHERN HALF OF
KENTUCKY. THUS...BROUGHT IN SOME BETTER POPS SATURDAY MORNING INTO
EARLY AFTERNOON. REALLY TOUGH TO NAIL DOWN WHERE THE FRONT WILL WIND
UP BY THE TIME THIS MCS ACTIVITY DEPARTS BY SATURDAY AFTERNOON...BUT
IT WILL LIKELY LIE ACROSS OUR REGION...LEADING TO CONTINUED CHANCES
FOR UNSETTLED WEATHER THROUGH THE REST OF THE WEEKEND AND PERHAPS
EVEN INTO EARLY NEXT WEEK. GOING TO KEEP POPS IN THE CHANCE CATEGORY
FOR THIS TIME PERIOD GIVEN LACK OF CERTAINTY IN THE FORECAST. THINGS
MAY EVENTUALLY DRY OUT...BUT CONFIDENCE IS NOT HIGH ON WHEN OR EVEN
IF THIS WILL HAPPEN. WITH A FLATTER MID LEVELS...A MORE PROGRESSIVE
PATTERN MAY SET UP LEADING TO MORE FREQUENT SHORTWAVES AND CHANCES
FOR RAIN. THUS...REALLY TOUGH TO GO DRY IN ANY EXTENDED PERIOD AT
THIS TIME. AS FAR AS TEMPERATURES...WILL BRING IN A BETTER GRADIENT
FOR FRIDAY INTO SATURDAY...AND KEEP THINGS MORE IN LINE WITH
GUIDANCE BEYOND THAT WITH VERY UNCERTAIN PLACEMENT OF THE BOUNDARY.
A SHARP NORTH/SOUTH GRADIENT WILL LIKELY EXIST INTO NEXT WEEK WITH
THIS BOUNDARY AROUND OUR REGION.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 206 PM EDT WED APR 25 2012
A FEW VFR CU SHOULD DEVELOP AT LEAST AT JKL EARLY IN THE PERIOD...
AND THERE IS A SMALL POTENTIAL FOR A SHOWER OR THUNDERSTORM DEVELOPING
AFTER 21Z IN ALL AREAS...BUT THEY WILL BE MORE LIKELY TO HOLD OFF
UNTIL AFTER 0Z. THE GREATEST PROBABILITY FOR CONVECTION STILL APPEARS
TO BE FROM ABOUT 03Z-09Z...ESPECIALLY ALONG AND NORTH OF A KLEX TO
KJKL TO KLNP LINE. THESE COULD EVENTUALLY BRIEFLY BRING CONDITIONS
AS LOW AS IFR ALONG WITH GUSTY WINDS AND PERHAPS SOME HAIL OR HAIL
ALOFT. ENOUGH SATURATION SHOULD OCCUR NEARER TO THE COLD FRONT THAT
WILL DROP INTO THE AREA TONIGHT THAT AFTER THE 6Z TIMEFRAME...SOME
PREVAILING MVFR SHOULD DEVELOP AND PERSIST FOR MOST OF...IF NOT THE
ENTIRE REMAINDER OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JP
LONG TERM....KAS
AVIATION...JP
AREA FORECAST DISCUSSION
NWS JACKSON KY
206 PM EDT WED APR 25 2012
.UPDATE...
ISSUED AT 206 PM EDT WED APR 25 2012
HOURLY TEMPERATURE AND DEWPOINT CURVES WERE FRESHENED UP BASED ON THE
LATEST OBS AND SAT TRENDS. ALSO...AT THIS POINT...WE OPTED TO RAISE
POPS TO LIKELY IN THE SW AND CAT IN THE FAR NORTH AS THE 12Z MODEL
SUITE AND RECENT SREF SUPPORT HIGHER POPS. MOS GUIDANCE FROM THE NAM
AND GFS IS GENERALLY LIKELY TO CAT ACROSS THE BOARD FOR TONIGHT.
MODELS GENERALLY AGREE IN CONVECTION DEVELOPING NEAR THE WARM FRONT
LATE IN THE AFTERNOON...OR POSSIBLY DURING THE EVENING WITH THE
POTENTIAL FOR MCS ACTIVITY TO AFFECT THE NORTH AND FAR EAST. SOME
MODELS HAVE THE INITIAL DEVELOPMENT OVER A STRIPE ACROSS THE CENTRAL
PART OF THE CWA NEAR JKL. CONFIDENCE IN EXACT PLACEMENT IS NOT ALL
THAT HIGH...BUT TRENDS IN CU WILL CONTINUE TO BE MONITORED TO FINE
TUE THIS. AS MODELS HAVE BEEN DOING LATELY AS NOTED BY SPC...MOISTURE
ADVECTION MAY BE A BIT TOO STRONG IN THE OPERATIONAL MODELS AND THUS
LEADING TO GREATER COVERAGE OF STRONGER CONVECTION THAN WHAT
ULTIMATELY WILL RESULT. HOWEVER...A STORM OR TWO THIS EVENING OR
TONIGHT COULD PRODUCE SOME MARGINALLY SEVERE HAIL AND OR
GUSTY...PERHAPS DAMAGING WINDS.
UPDATE ISSUED AT 1110 AM EDT WED APR 25 2012
THE MAIN UPDATES FOR THIS PERIOD WERE TO ADJUST THE NEAR TERM HOURLY
TEMP AND DEWPOINT CURVES TO MORE ABRUPT RISES TO ACCOUNT FOR THE WARM
FRONT LIFTING FURTHER NE INTO OUR CWA AND INITIAL CLOUDS IN THE
EASTERN TWO THIRDS OF THE CWA AND POPS LATE IN DAY INTO EARLY IN THE
EVENING. HIGHS FOR TODAY STILL APPEAR ON TARGET.
WE HAVE ALSO OPTED TO GO WITH A SLIGHT CHANCE POP ACROSS THE ENTIRE
AREA FOR LATE IN THE FIRST PERIOD. THE MOST RECENT NAM AND HRRR AS
WELL AS 9Z SREF ALL SUPPORT SOME CONVECTION DEVELOPING LATE IN THE
DAY IN THE VICINITY OF THE WARM FRONT. GIVE PROJECTED SHEAR...THIS
CONVECTION LATE IN THE DAY TO EARLY IN THE EVENING COULD BECOME
STRONG TO POSSIBLY MARGINALLY SEVERE. THIS THREAT WILL CONTINUE TO BE
MONITORED.
UPDATE ISSUED AT 703 AM EDT WED APR 25 2012
RADAR TRENDS SUGGEST PRECIP WILL BE OUT OF THE FORECAST AREA WITHIN
ABOUT AN HOUR. HAVE UPDATED GRIDS FOR LATEST RADAR COVERAGE/TRENDS.
WILL ISSUE A NEW ZFP SHORTLY ONCE THE EARLY MORNING PRECIP IS
FINISHED.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 339 AM EDT WED APR 25 2012
ISENTROPIC LIFT ASSOCIATED WITH A WARM FRONT MOVING TOWARD US FROM
THE SOUTHWEST WAS PRESENT OVERNIGHT...AND AN UPPER LEVEL JET STREAK
ON THE WEST SIDE OF AN EAST COAST TROUGH WAS ALSO HAVING AN
INFLUENCE. THE COMBINATION WAS BRINGING WIDESPREAD SHOWERS...AND SOME
ISOLATED THUNDERSHOWERS UPSTREAM. MODELS AGREE THAT THIS ACTIVITY
SHOULD MOVE SOUTHEAST AND WIND DOWN BY 12Z. HOWEVER...PRECIP BEFORE
THEN WILL NECESSITATE A PRE-FIRST PERIOD IN THE ZFP.
AFTER THE EARLY MORNING PRECIP IS DONE...SIGNIFICANT WARMING ALOFT
WILL TEND TO KEEP A CAP ON SURFACE BASED CONVECTION DURING THE DAY.
HOWEVER...NAM FORECAST SOUNDINGS SHOW SOME POTENTIAL FOR CONVECTION
OVER THE NORTHEAST PART OF THE FORECAST AREA BY THE END OF THE
PERIOD. MEANWHILE...IN OUR NORTHEAST COUNTIES THE GFS IS INDICATING
SATURATION IN THE MID- UPPER LEVELS BY THE END OF THE DAY DUE TO
STRONG WARM AIR ADVECTION. IF THIS OCCURS...IT IS QUESTIONABLE
WHETHER OR NOT WE COULD SEE PRECIP...OR JUST VIRGA. CONSIDERING BOTH
VARYING SCENARIOS...A LOW POP IS JUSTIFIED IN OUR NORTHEAST COUNTIES.
THE WARM FRONT IS FORECAST TO MOVE NORTHEAST OVER THE FORECAST AREA
TONIGHT. MODELS ARE GENERATING AN MCS ALONG THE FRONT TONIGHT...BUT
DISAGREE ON LOCATION. AN AVERAGE OF RECENT RUNS PLACES THE MOST
PROBABLE TRACK ACROSS OUR NE COUNTIES...AND WILL CARRY THE HIGHEST
POPS THERE. HOWEVER...WITH THE NATURE OF NOCTURNAL MCS ACTIVITY...
CONFIDENCE IS NOT HIGH. WILL CARRY LIKELY POPS NORTHEAST AND CHANCE
SOUTHWEST. WITH SWIFT FLOW ALOFT AND MCS POTENTIAL...THERE IS CONCERN
FOR A SEVERE THREAT...AS INDICATED BY SLIGHT RISK FROM SPC.
ANY LINGERING PRECIP WITH THE NIGHT TIME SYSTEM SHOULD DWINDLE IN THE
MORNING. THE LOW PRESSURE SYSTEM WHICH FIRST PULLS THE WARM FRONT
THROUGH WILL PASS EASTWARD ON THURSDAY...AND SEND THE FRONT BACK
SOUTH INTO THE REGION AS A COLD FRONT. WILL LOOK FOR SOME LIMITED
POTENTIAL OF CONVECTIVE REDEVELOPMENT ALONG AND AHEAD OF THE FRONT
LATE IN THE DAY THURSDAY.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 339 PM EDT TUE APR 24 2012
THE MODELS CONTINUE TO SHOW GOOD AGREEMENT ON THE OVERALL FAIRLY
AMPLIFIED LONG WAVE PATTERN TO DOMINATE THE CONUS THROUGH THE WEEKEND
BEFORE DAMPENING BY EARLY NEXT WEEK. THE DETAILS UNFORTUNATELY
REMAIN VERY UNCERTAIN...LEADING TO A LOWER CONFIDENCE FORECAST.
THE MAIN PLAYER FOR OUR WEATHER WILL BE A LINGERING SURFACE FRONTAL
BOUNDARY...WHICH WILL BE DROPPING SOUTH INITIALLY AS A COLD FRONT ON
THURSDAY NIGHT...BEFORE RETURNING TO THE NORTH AS A WARM FRONT BY
FRIDAY...AND THEN STALLING NEAR OR JUST NORTH OF THE AREA THROUGH
THE WEEKEND. CONVECTION WILL PLAY A BIG ROLE IN THIS TYPE OF
PATTERN...SO HAVE STUCK FAIRLY CLOSE TO THE BLENDED SOLUTION THROUGH
THE WEEKEND.
THEREAFTER...HAVE DECIDED TO STICK CLOSER TO THE INHERITED
FORECAST...ALLOWING FOR A PERIOD OF DRY WEATHER FROM SUNDAY NIGHT
THROUGH MONDAY NIGHT. THE LATEST 00Z MODEL RUNS ARE DEVIATING
QUITE A BIT ON THE DETAILS COMPARED TO PREVIOUS RUNS AS THE LONG
WAVE PATTERN TRANSITIONS BACK TO FLATTER FLOW. THIS MAINLY RESULTS
IN LINGERING THE FRONTAL BOUNDARY EVEN LONGER ACROSS THE
AREA...WHICH IS CERTAINLY POSSIBLE IF THIS IS A TRUE TREND.
FOR TEMPERATURES...AGAIN...STUCK CLOSE TO THE BLENDED GUIDANCE...
WITH THE POTENTIAL FOR MODERATE TO LARGE GRADIENTS ACROSS THE AREA
FROM NORTH TO SOUTH.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 206 PM EDT WED APR 25 2012
A FEW VFR CU SHOULD DEVELOP AT LEAST AT JKL EARLY IN THE PERIOD...
AND THERE IS A SMALL POTENTIAL FOR A SHOWER OR THUNDERSTORM DEVELOPING
AFTER 21Z IN ALL AREAS...BUT THEY WILL BE MORE LIKELY TO HOLD OFF
UNTIL AFTER 0Z. THE GREATEST PROBABILITY FOR CONVECTION STILL APPEARS
TO BE FROM ABOUT 03Z-09Z...ESPECIALLY ALONG AND NORTH OF A KLEX TO
KJKL TO KLNP LINE. THESE COULD EVENTUALLY BRIEFLY BRING CONDITIONS
AS LOW AS IFR ALONG WITH GUSTY WINDS AND PERHAPS SOME HAIL OR HAIL
ALOFT. ENOUGH SATURATION SHOULD OCCUR NEARER TO THE COLD FRONT THAT
WILL DROP INTO THE AREA TONIGHT THAT AFTER THE 6Z TIMEFRAME...SOME
PREVAILING MVFR SHOULD DEVELOP AND PERSIST FOR MOST OF...IF NOT THE
ENTIRE REMAINDER OF THE PERIOD.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...HAL
LONG TERM....GEOGERIAN
AVIATION...JP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
415 PM EDT WED APR 25 2012
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 414 PM EDT WED APR 25 2012
SEVERAL EMBEDDED SHORTWAVES HAVE BEEN MOVING THROUGH THE NW FLOW
ACROSS THE UPPER MISS VALLEY AND UPPER GREAT LKS TODAY. WHEN THESE
WAVES HAVE INTERACTED WITH THE H925-700 WAA UNDER WEAK SW FLOW...AS
SEEN ON RUC ANALYSIS...THEY HAVE PRODUCED AREAS OF LIGHT RAIN
SHOWERS OVER NE MN...NW WI AND ALONG THE WI/MI BORDER. WITH THE
LLVL DRY AIR IN PLACE OVER MUCH OF UPPER MI AND LITTLE ESE MOVEMENT
OF THE SHOWERS...THEY HAVE STRUGGLED TO EFFECT THE AREA. ATTENTION
THEN TURNS FARTHER UPSTREAM IN SW ONTARIO WHERE ANOTHER SHORTWAVE
AND WEAK WAA HAS BEEN SLOWLY MOVING SE INTO WRN LK SUPERIOR. THIS
AREA OF MOISTURE/WAA WILL MERGE WITH SHORTWAVE DROPPING S JUST E OF
LK WINNIPEG AND MOVE ACROSS LAKE SUPERIOR TONIGHT. 06 AND 12Z MODEL
RUNS REALLY TRENDED THAT DIRECTION AND EARLIER UPDATE TO THE
FORECAST WENT WITH THIS IDEA.
THINK THESE SHOWERS WILL SLIDE INTO THE WRN PART OF UPPER MI THIS
EVENING AND TRY TO SPEED UP AS FRONTAL BOUNDARY ASSOCIATED WITH
THE SHORTWAVE PUSHES IT TO THE SE. AS THIS SLIDES ESE ACROSS THE
AREA...IT WILL BE INTERACTING WITH THE LINGERING DRY LLVL AIR.
MODELS CONSISTENT ON THIS PCPN DIMINISHING SOME AS IT HITS THE DRIER
AIR...SO HAVE THE LIKELY POPS OVER THE WRN HALF OF THE CWA AN
DIMINISHED TO CHANCES AS IT MOVES INTO THE DRIER AIR. AFTER THE
INITIAL PCPN SLIDES THROUGH...COULD HAVE A SECONDARY AREA ASSOCIATED
WITH THE SFC-H850 FRONT MOVING THROUGH AFTER 6Z. FORCING ALONG THE
FRONT...ALONG WITH THE STRONG SHORTWAVE...SHOULD LEAD TO ANOTHER
BAND OF RAIN...POTENTIALLY MIXING WITH OR CHANGING TO SNOW
AFFECTING THE NRN HALF OF THE CWA. SOME OF THESE SHOWERS WILL BE
ENHANCED IN THE UPSLOPE N FLOW AREAS...WHICH IF IT CHANGES TO ALL
SNOW...COULD PRODUCE A LIGHT DUSTING OF SNOW OVER THE WEST AND
NCNTRL. EXPECT WINDS TO QUICKLY PICKUP ALONG THIS FRONT AND GUST TO
25-30KTS NEAR LK SUPERIOR LATE TONIGHT AND INTO THURS MORNING.
CONSIDERED PUTTING UP A GALE FOR THE ERN HALF OF LK
SUPERIOR...AS WINDS RIGHT ALONG THE FRONT WILL GUST TO 35 AND
POTENTIALLY 40KTS...BUT SHOULD ONLY BE FOR A BRIEF 1-2HR WINDOW
BEFORE DIMINISHING BACK BELOW 35KTS.
AS THE FRONT QUICKLY MOVES THROUGH...H850 TEMPS AROUND -9C WILL
PROVIDE ENOUGH DELTA-T FOR CLOUDS AS LONG AS MOISTURE REMAINS.
SHOULD BE ENOUGH LLVL MOISTURE...AROUND H925-850...TO SUSTAIN
CLOUDS NEAR LK SUPERIOR FOR THE FIRST PART OF THE MORNING OVER THE
WEST AND INTO THE AFTN OVER THE EAST. DID LEAVE SOME LINGERING
-SHSN FOR UPSLOPE LOCATIONS NEAR LK SUPERIOR OVER THE NCNTRL AND
EAST...BUT SHOULD DIMINISH FAIRLY QUICKLY WITH THE DRY AIR AND
SUBSIDENCE FROM HIGH PRESSURE RIDGE MOVING OVER WRN LK SUPERIOR. IT
WILL FEEL MUCH COOLER THAN TODAY OVER MUCH OF THE AREA...BUT
ESPECIALLY OVER THE N HALF...AS THE COLD AIR AND WINDS OFF LK
SUPERIOR WILL MAKE IT FEEL MUCH COLDER THAT THE LOW-MID 40S HIGHS.
IN ADDITION...WITH THE DRY AIR ALOFT AND MIXING WITH THE WINDS WILL
LEAD TO FALLING DEWPOINTS FROM WEST TO EAST. RH FALLING TO 25-30
PERCENT OVER THE WEST...BUT FORTUNATELY THE WINDS WILL BE
DIMINISHING AND COOLER TEMPS WILL LIMIT FIRE WX CONCERN.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 414 PM EDT WED APR 25 2012
DRY CONDITIONS MAIN THEME OF LONG TERM. VERY LIMITED OPPORTUNITIES
FOR RAINFALL IS IN THE FCST THROUGH MONDAY AS HIGH PRESSURE REGINS
OVR THE REGION. INITIALLY WINDS WILL BE OUT OF THE NORTH OR
NORTHEAST AS THE HIGH CENTER SETTLES FM NORTHERN MANITOBA AND
NINAVUT CANADA ACROSS MUCH OF THE EASTERN CONUS BY EARLY NEXT WEEK.
HIGH IS FCST TO PUSH TOWARD EAST CONUS COAST BY TUESDAY ALLOWING
SOUTH TO SOUTHWEST RETURN FLOW TO FORM FM THE PLAINS INTO THE
WESTERN GREAT LAKES. MOISTURE RETURN INTO GREAT LAKES IS MINIMAL
AND DESPITE APPROACH OF A SFC-H85 TROUGH BELIEVE CHANCES OF ANY
PRECIPITATION ARE PRETTY SMALL. CONSENSUS OF AVAILABLE MODELS
GIVES LOW CHANCE POPS TUESDAY THROUGH WEDNESDAY AS THE TROUGH WORKS
THROUGH.
LARGE TROUGH RESIDING OVER MUCH OF EASTERN CANADA AND NORTHEAST
CONUS WILL KEEP TEMPS GENERALLY AT OR BLO NORMAL THROUGH MUCH OF THE
PERIOD...ESPECIALLY NEAR LK SUPERIOR WITH PERSISTENT ONSHORE FLOW.
NEAR NORMAL OR POSSIBLY SLIGHTLY ABOVE NORMAL TEMPS MAY OCCUR OVR
INTERIOR CNTRL TOWARD WI BORDER AS DEEP MIXING OFFSETS NORTHERLY
WINDS. PRIME ISSUE THROUGH THE EXTENDED PERIOD REALLY IS DWPNTS/RH
VALUES WITH THE DRY HIGH DOMINATING. CORE OF DRIEST AIR IS OVER THE
AREA THURSDAY NIGHT THROUGH MONDAY. LOWERED DWPNTS MORE TOWARD MIXED
LAYER DWPNT TOOL OUTPUT FOR AFTN HOURS ON FRIDAY...SATURDAY...AND
SUNDAY. SIMILAR TO EARLIER THIS WEEK...GIVEN EXTENT OF DRY AIRMASS
OVERHEAD /PWATS 10-20 PCT OF NORMAL/...WOULD NOT BE SHOCKED AT ALL
TO SEE AFTN DWPNTS NEAR 0F AND RH VALUES WELL BLO 20 PCT. NNW
GRADIENT WINDS STRONGEST ON FRIDAY AFTN OVR EAST HALF...SO THAT IS
PROBABLY WHEN FIRE WX ISSUES WOULD BE MAXIMIZED. OTHERWISE...THROUGH
THE WEEKEND...WINDS BECOME PRETTY LIGHT AS HIGH PRESSURE RIDGE AXIS
IS OVERHEAD.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 149 PM EDT WED APR 25 2012
A WEAK LOW PRESSURE TROUGH APPROACHING THE AREA HAS SPREAD VFR
CLOUDS ACROSS WRN UPPER MI THIS MORNING. AREA OF SHOWERS JUST NW OF
KIWD SHOULD AFFECT THE SITE AT 18Z AND LAST FOR A COUPLE HOURS
BEFORE DIMINISHING. BASED ON UPSTREAM OBS...HAVE KEPT THEM AT VFR
COND WITH THE SHOWERS. AS THE TROUGH NEARS AND PUSHES THROUGH
TONIGHT...EXPECT THE CIGS TO LOWER TO MVFR AND THE COVERAGE OF
SHOWERS TO INCREASE AT KCMX/KSAW. SOME HINTS AT IFR CIGS WITH
THE RA/SN SHOWERS FOR A BRIEF PERIOD RIGHT BEHIND THE TROUGH WITH
UPSLOPE FLOW...BUT HAVE HELD AT LOW END MVFR. BEHIND THE
FRONT...STRONG NRLY WINDS WILL GUST TO 25-30KTS FOR A COUPLE HOUR
PERIOD BEFORE GRADUALLY DIMINISHING THROUGH THE MORNING. EXPECT
CLEARING SKIES THROUGH THE MORNING HAS HIGH PRESSURE RIDGE MOVES
IN.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 414 PM EDT WED APR 25 2012
LOW PRESSURE OVER IOWA WILL SLIDE SE TONIGHT AND DRAG A SFC
TROUGH SE ACROSS LAKE SUPERIOR. STRONG CANADIAN HIGH TRIES TO
PUSH IN BEHIND IT AND WILL LEAD TO GUSTY NNW WINDS LATE TONIGHT
INTO THURS MORNING. EXPECT A FEW GALE FORCE GUSTS TO 35KTS OVER
CNTRL/ERN LK SUPERIOR WITH THIS STRONG GRADIENT. CONSIDERED PUTTING
UP A GALE FOR A COUPLE HOUR PERIOD AS THIS BOUNDARY MOVES ACROSS LK
SUPERIOR...BUT WITH THE SHORT TIME PERIOD...OPTED TO MENTION THE
GUSTS AT THIS TIME. THE CANADIAN HIGH PRESSURE RIDGE WILL THEN MOVE
OVER THE UPPER GREAT LKS BY THURS NIGHT DIMINISHING THE WINDS BELOW
20KTS. THIS WILL CONTINUE THROUGH MONDAY...AS THE HIGH MOVES
SOUTHEAST ACROSS THE GREAT LAKES REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...SRF
LONG TERM...JLA
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS HASTINGS NE
405 PM CDT WED APR 25 2012
.SHORT TERM...THROUGH THURSDAY AFTERNOON. PRIMARY CONCERN IN THE
NEXT 24 HOURS IS HOW MUCH OF THE CWA STANDS TO SEE MEASURABLE
RAINFALL...AND THE MAIN THEME HERE IS THAT THESE CHANCES CONTINUE
TO DECREASE IN MOST AREAS...WITH MUCH BETTER CHANCES HOLDING OFF
UNTIL THE THURSDAY NIGHT PERIOD AS DISCUSSED IN THE LONG TERM
SECTION BELOW. ALSO...ALL MENTION OF THUNDERSTORMS HAS BEEN PULLED
THROUGH THURSDAY AFTERNOON THANKS TO VERY MEAGER INSTABILITY.
19Z OBJECTIVE SURFACE ANALYSIS PLACES A WEAK 1000MB LOW OVER
CENTRAL IA...WITH A TROUGH AXIS/WEAK COLD FRONT TRAILING
SOUTHWESTWARD ACROSS EASTERN/SOUTH CENTRAL KS. IN THE WAKE OF THIS
BOUNDARY...NORTH BREEZES GUSTING TO AROUND 30 MPH AND LOCALLY
HIGHER HAVE BEEN COMMON ACROSS THE CWA THIS AFTERNOON. DESPITE
NEUTRAL TO EVEN WEAK COLD AIR ADVECTION EVIDENT AT 850MB...TEMPS
HAVE AGAIN SOARED TO AT LEAST NEAR-RECORD LEVELS IN MANY
CENTRAL/SOUTHERN COUNTIES THANKS TO DEEP MIXING INTO THE
750-700MB RANGE PER FORECAST SOUNDINGS. SLIGHTLY COOLER TEMPS HAVE
TAKEN HOLD IN THE NORTHWESTERN CWA...RESULTING IN A RANGE FROM
LOW-MID 80S NORTHWEST TO MAINLY LOW 90S SOUTHEAST. UNLIKE
YESTERDAY..IT APPEARS TRI-CITIES TEMP RECORDS FOR THE DAY ARE
LIKELY SAFE. LOOKING ALOFT...WATER VAPOR IMAGERY AND SHORT TERM
MODEL DATA CONFIRM A BROAD RIDGE CENTERED OVER THE ROCKIES...WITH
AN UPSTREAM TROUGH AND CLOSED 500MB LOW APPROACHING THE SOUTHERN
CAL COAST. A SUBTROPICAL MOISTURE PLUME IN THE MID/UPPER LEVELS IS
RIDING AROUND THE TOP OF THE RIDGE AND HAS RESULTED IN A FAIRLY
THICK BUT NARROW PLUME OF CIRRUS OVERSPREADING MUCH OF THE
SOUTHWEST 1/2 OF THE CWA TODAY. MEANWHILE...SOME HIGH BASED
CUMULUS AND EVEN SOME WEAK THUNDERSHOWERS ARE POPPING AT THIS HOUR
ALONG AN AXIS FROM THE WESTERN NEBRASKA SANDHILLS BACK UP INTO THE
BLACK HILLS.
LATE THIS AFTERNOON THROUGH AT LEAST MIDNIGHT...THE VAST
MAJORITY...IF NOT THE ENTIRE CWA WILL STAY DRY AS THE AIRMASS OVER
THE LOCAL AREA IS QUITE CAPPED TO LOW-LEVEL PARCELS. HOWEVER...AM
A BIT WARY THAT A LIGHT SHOWER OR MAYBE EVEN A WEAKENING
THUNDERSTORM OR TWO COULD TRY MAKING AN RUN AT A FEW OF THE
NORTHWEST COUNTIES IN THE 22Z-02Z TIME FRAME...AS ACTIVITY
DEVELOPING IN THE VERY STEEP LOW LEVEL LAPSE RATE ENVIRONMENT OFF
THE SANDHILLS DRIFTS SOUTHEAST. THIS ACTIVITY IS WELL CAPTURED BY
THE LATEST HRRR RUNS...BUT EVEN THIS MODEL...WHICH IS MOST
AGGRESSIVE WITH THIS ACTIVITY FADES MOST OF IT OUT BEFORE IT
ENTERS THE NORTHWEST COUNTIES. EVENING SHIFT WILL HAVE TO KEEP AN
EYE ON THIS...BUT AM GOING TO ONLY GO WITH A SLIGHT CHANCE
SPRINKLE MENTION FOR NOW...AND ASSUME THAT ANY HEAVIER SHOWERS OR
WEAK THUNDERSTORMS LOSE STEAM BEFORE THEY WOULD GET IN. TURNING TO
THE POST-MIDNIGHT HOURS...PULLED THUNDERSTORM MENTION
ALTOGETHER...AND EVEN PULLED MEASURABLE POPS...LEAVING ONLY A
SLIGHT CHANCE SPRINKLE MENTION IN FAR WESTERN COUNTIES AFTER 08Z.
INSTABILITY IS VIRTUALLY NON-EXISTENT LATE TONIGHT...AND THE ONLY
FORCING FOR PRECIP WILL BE A GRADUAL MID-LEVEL TOP-DOWN MOISTENING
FROM WEST TO EAST EVIDENT IN THE DEWPOINT AND RH FIELD AT 700MB ON
MODELS SUCH AS THE 12Z NAM. BETTER CHANCES FOR MEASURABLE LIGHT
SHOWERS LATE TONIGHT WILL CERTAINLY RESIDE JUST WEST OF THE CWA
OVER THE GLD FORECAST AREA. OTHERWISE...WINDS THIS EVENING WILL
QUICKLY DIMINISH...WITH LIGHT FLOW GRADUALLY TURNING FROM
NORTHERLY TO EASTERLY AS A SURFACE RIDGE AXIS CENTERED WELL TO THE
NORTH MIGRATES EASTWARD. CHANGED LOW TEMPS LITTLE FROM PREVIOUS
FORECAST...AND WITH MID LEVEL CLOUDS ON THE INCREASE...WILL KEEP
THINGS GENERALLY 2-3 DEGREES ABOVE MET/MAV GUIDANCE
CONSENSUS...BOTTOMING OUT MOST OF THE CWA BETWEEN 54-58 DEGREES.
ON THURSDAY...THE HEART OF THE MID/UPPER RIDGE AXIS WILL PASS
OVERHEAD...AS THE UPSTREAM COMPACT BUT STRONG CLOSED LOW GRADUALLY
MIGRATES FROM NEAR THE FAR SOUTHERN TIP OF CAL AT 12Z TO NEAR THE
4-CORNERS BY 00Z. WITH THIS FEATURE REMAINING WELL OFF TO THE
SOUTHWEST OF THE CWA...APPRECIABLE FORCING WILL REMAIN
WEAK...DESPITE INCREASING MID/HIGH LEVEL CLOUD COVER AND WEAK
FORCING ASSOCIATED WITH A SUBTLE LEAD WAVE. THE 12Z NAM WAS QUITE
SUPPORTIVE OF PULLING THUNDER MENTION...WITH EVEN ELEVATED CAPE
NEGLIGIBLE. HOWEVER...WILL FOLLOW NAM SOLUTION FAIRLY CLOSELY...WITH
BEST CHANCE FOR LIGHT SHOWERS FOCUSED ACROSS THE NORTHWEST 1/4 OF
THE CWA AS WEAK LIFT FROM THE LEAD SHORTWAVE KEEPS MID LEVEL
THETA-E ADVECTION ALIVE. EVEN OUTSIDE THIS MOST FAVORED
AREA...KEPT AT LEAST A SLIGHT CHANCE POP OR A SPRINKLE MENTION
GOING CWA-WIDE ESPECIALLY DURING THE AFTERNOON...BUT WOULD BE
SURPRISED TO SEE MOST AREAS MEASURE MORE THAN A FEW HUNDREDTHS OF
AN INCH...AND A GOOD PERCENTAGE OF THE AREA LIKELY STAYING DRY.
TEMPS WILL BE A BIT TRICKY...WITH PLENTIFUL CLOUD COVER AND
INCREASING EASTERLY WINDS INTO THE 15-20 MPH RANGE DURING THE
AFTERNOON. IT WILL CERTAINLY BE COOLER THAN THESE PAST FEW DAYS
THOUGH. OPTED TO MAKE LITTLE CHANGE TO PREVIOUS FORECAST...AND
DIDN/T STRAY MORE THAN A FEW DEGREES FROM MET/MAV GUIDANCE
CONSENSUS...RESULTING IN A RANGE FROM LOW-MID 70S IN NEB
ZONES...TO MID-UPPER 70S IN KS ZONES. THESE HIGHS COULD EASILY BE
OFF A BIT THOUGH BASED ON CLOUD/PRECIP TRENDS OR LACK THEREOF.
.LONG TERM...THURSDAY NIGHT THROUGH WEDNESDAY. BEGINNING THE MID
TERM PERIOD...THE UPPER LEVEL RIDGE WHICH BROUGHT WARM
TEMPERATURES AND RECORD HIGHS TO THE PLAINS WILL BEGIN TO BREAK
DOWN...MAINLY DUE TO AN UPPER LEVEL TROUGH PUSHING ACROSS THE WEST
COAST. AHEAD OF THIS TROUGH...A BURST OF TROUGH ENERGY IN THE FORM
OF A SHORT WAVE/CLOSED LOW WILL BEGIN TO SLIDE THROUGH THE PLAINS
THURSDAY NIGHT INTO FRIDAY.
AS LOW PRESSURE DEVELOPS ALONG THE FRONT RANGE OF THE ROCKIES...AN
INCREASED PRESSURE GRADIENT WILL HELP INCREASE EASTERLY WINDS
OVERNIGHT THURSDAY. A SURGE OF MOISTURE WILL MOVE INTO THE PLAINS
OVERNIGHT...AND COMBINED WITH UPPER LEVEL FORCING AND ISENTROPIC
LIFT...CREATE A GOOD CHANCE FOR PRECIPITATION DURING THE OVERNIGHT
HOURS ON THURSDAY...ESPECIALLY AFTER MIDNIGHT. THUNDERSTORM CHANCES
CERTAINLY REMAIN POSSIBLE ESPECIALLY ACROSS THE SOUTHWEST PORTIONS
OF THE FORECAST AREA BEFORE MIDNIGHT AS THE THE DRY LINE MIXES
EASTWARD. CANNOT RULE OUT A STRONG TO SEVERE THUNDERSTORM ACROSS THE
SOUTHEAST...DEPENDENT UPON WHERE THE DRY LINE SETS UP. AFTER
MIDNIGHT AND THROUGH THE DAY ON FRIDAY...BOTH THE GFS AND THE ECMWF
SOLUTION KEEP THE SURFACE LOW WELL TO THE SOUTH OF THE FORECAST
AREA...THUS KEEPING MUCH OF THE MAIN INSTABILITY AXIS TO THE SOUTH.
THE NAM SOLUTION IS A BIT TRICKIER AND KEEPS THE LOW SLIGHTLY
FURTHER NORTH. A LARGE AREA OF WRAP AROUND MOISTURE WILL INFILTRATE
THE PLAINS...FUELED BY GOOD ISENTROPIC LIFT AND UPPER LEVEL
DIFFLUENCE. AT THIS TIME...GIVEN THE DIFFERENCE IN SOLUTIONS...CANNOT
RULE OUT ISOLATED THUNDERSTORM CHANCES THROUGH THE DAY ON FRIDAY.
THE UPPER LEVEL SHORT WAVE BEGINS TO KICK OFF TO THE EAST BY
SATURDAY MORNING...WITH LINGERING POPS ACROSS THE NORTHWEST.
SATURDAY LOOKS TO BE PRECIPITATION FREE...WITH PARTLY CLOUDY SKIES.
AS A RESULT...DECIDED TO UP TEMPERATURES SLIGHTLY ACROSS THE
REGION...WITH MID 60S EXPECTED.
THE MAIN UPPER LEVEL LOW FINALLY SHIFTS NORTHWARD BY SUNDAY EVENING.
HOWEVER...NUMEROUS MID LEVEL SHORT WAVES CONTINUE TO IMPACT THE
PLAINS THROUGH THE LONG TERM PERIOD. SEVERAL SURFACE LOWS DEVELOP
ALONG THE FRONT RANGE...PROVIDING SEVERAL CHANCES FOR RAIN SHOWERS
THROUGH THE PERIOD.
SPECIFICALLY...MONDAY NIGHT THROUGH TUESDAY...AN AREA OF UPPER LEVEL
POSITIVE VORTICITY COMBINED WITH SURFACE LOWS WILL BRING A DECENT
SHOT OF RAIN SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA.
INSTABILITY PARAMETERS SUGGEST MUCAPES NEAR 500 J/KG. AT THIS
TIME...CANNOT RULE OUT A STRONG THUNDERSTORM OR TWO.
WHILE THE WEEKEND WILL BE FAIRLY COOL...WITH HIGHS IN THE UPPER 50S
TO LOWER 60S...WARMER TEMPERATURES RETURN TO THE FORECAST AREA BY
TUESDAY...WITH LOWER 70S EXPECTED.
&&
.PREV DISCUSSION... /ISSUED 1209 PM CDT WED APR 25 2012/
AVIATION...18Z KGRI TAF. VFR CEILING/VISIBILITY IS FORECAST
THROUGHOUT THE PERIOD...THUS MAKING WIND SPEEDS/DIRECTION THE MAIN
ISSUE. THE STRONGEST WINDS OF THE PERIOD WILL FOCUS THIS
AFTERNOON...WITH NORTHERLY GUST POTENTIAL TO AROUND 25KT.
TONIGHT...SURFACE HIGH PRESSURE WILL RESULT IN MUCH LIGHTER
SPEEDS...AND A GRADUAL DIRECTIONAL CHANGE FROM NORTHERLY TO
EASTERLY. THESE EASTERLY WINDS WILL PICK UP A BIT ON THURSDAY
MORNING...BUT WITH PREVAILING SPEEDS BELOW 12KT. AS FOR
CLOUDS/PRECIP CHANCES...WILL SEE AN INCREASE IN HIGH AND
EVENTUALLY MID LEVEL CLOUDS AS TIME GOES BY...BUT EVEN LATE IN THE
PERIOD CEILINGS SHOULD STILL BE ABOVE 15K FT AGL. COULD SEE SOME
RAIN SHOWER POTENTIAL APPROACHING THE AREA DURING THE LAST 3 HOURS
OF THE PERIOD...BUT CONFIDENCE IN RAIN IS LOW ENOUGH GIVEN SUCH
DRY LOW LEVELS WILL OMIT MENTION FOR NOW.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...PFANNKUCH
LONG TERM...SALTZMAN
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1209 PM CDT WED APR 25 2012
.UPDATE...OVERALL THE PREVIOUSLY ISSUED FORECAST FOR THIS
AFTERNOON REMAINS VERY MUCH ON TRACK...WITH ONE MORE WARM/HOT DAY
BEFORE A RETURN TO MORE SPRING-LIKE CONDITIONS FOR SEVERAL DAYS.
16Z OBJECTIVE RUC ANALYSIS INDICATES THAT THE WEAK COLD FRONT HAS
ESSENTIALLY CLEARED THE ENTIRE CWA...WITH NORTHERLY WINDS IN ITS
WAKE. SPEAKING OF WINDS...THE MAIN CHANGE WITH THE UPDATED
FORECAST WAS TO INCREASE GUST POTENTIAL TO AROUND 30 MPH VERSUS 25
MPH...AS EFFICIENT MIXING CLIMBING WAY UP INTO THE 750-700MB RANGE
PER 12Z NAM FORECAST SOUNDINGS WILL HELP TAP INTO A BIT OF THIS
GUSTINESS. AS FOR AFTERNOON TEMPS...FOR THE 2ND STRAIGHT DAY TEMPS
HAVE SOARED WELL INTO THE 80S BY NOON MOST AREAS...BUT EXPECT
NEUTRAL TO EVEN VERY WEAK COLD AIR ADVECTION TO KEEP THINGS A FEW
DEGREES COOLER THAN YESTERDAY...AND HAVE AIMED FOR A RANGE FROM
MID-UPPER 80S NORTHWEST TO LOW-MID 90S SOUTHEAST. THAT BEING
SAID...DID KNOCK NORTH CENTRAL KS HIGHS DOWN VERY SLIGHTLY...NOW
KEEPING THEM BELOW 95 DEGREES. ALTHOUGH THE COMBINATION OF GUSTY
WINDS AND DECREASING DEWPOINTS DUE TO DEEP MIXING WILL BE LOWERING
RELATIVE HUMIDITY VALUES BELOW 20 PERCENT THIS AFTERNOON ACROSS
MUCH OF THE CWA...AT LONG LAST THE OFFICIAL FIRE FUEL STATUS IS
NOW UNFAVORABLE FOR LARGE FIRE GROWTH DUE TO GREEN-UP AND RECENT
RAINFALL...SO THUS NO NEED FOR RED FLAG HEADLINES.
&&
.AVIATION...18Z KGRI TAF. VFR CEILING/VISIBILITY IS FORECAST
THROUGHOUT THE PERIOD...THUS MAKING WIND SPEEDS/DIRECTION THE MAIN
ISSUE. THE STRONGEST WINDS OF THE PERIOD WILL FOCUS THIS
AFTERNOON...WITH NORTHERLY GUST POTENTIAL TO AROUND 25KT.
TONIGHT...SURFACE HIGH PRESSURE WILL RESULT IN MUCH LIGHTER
SPEEDS...AND A GRADUAL DIRECTIONAL CHANGE FROM NORTHERLY TO
EASTERLY. THESE EASTERLY WINDS WILL PICK UP A BIT ON THURSDAY
MORNING...BUT WITH PREVAILING SPEEDS BELOW 12KT. AS FOR
CLOUDS/PRECIP CHANCES...WILL SEE AN INCREASE IN HIGH AND
EVENTUALLY MID LEVEL CLOUDS AS TIME GOES BY...BUT EVEN LATE IN THE
PERIOD CEILINGS SHOULD STILL BE ABOVE 15K FT AGL. COULD SEE SOME
RAIN SHOWER POTENTIAL APPROACHING THE AREA DURING THE LAST 3 HOURS
OF THE PERIOD...BUT CONFIDENCE IN RAIN IS LOW ENOUGH GIVEN SUCH
DRY LOW LEVELS WILL OMIT MENTION FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 424 AM CDT WED APR 25 2012/
SHORT TERM...TODAY THROUGH FRIDAY NIGHT. PRIMARY FORECAST CONCERN
LIES WITH TEMPERATURES TODAY AND PRECIPITATION CHANCES
THROUGHOUT THE SHORT TERM PERIOD.
UPPER AIR PROFILER AND SATELLITE DATA CONTINUES TO SHOW
NORTHWESTERLY FLOW ACROSS THE PLAINS EARLY THIS MORNING...THOUGH
NOT AS AMPLIFIED OF A PATTERN AS THE PAST FEW DAYS...THANKS TO
SMALL PIECES OF ENERGY BREAKING DOWN THE RIDGE. THIS WEAKER RIDGE
AXIS REMAINS OVER THE ROCKIES...WHILE A LOW PRESSURE SYSTEM AND
ASSOCIATED TROUGH CONTINUE TO AFFECT THE EASTERN CONUS. ONE OF
THESE DISTURBANCES IS MAKING ITS WAY SE OUT OF THE DAKOTAS...AND
STILL SEEING A BIT OF LIGHT PRECIPITATION IN AN AREA OF WEAK WAA
AHEAD OF THIS DISTURBANCE...BUT IS MAINLY EAST OF THE CWA. LOOKING
AT THE SFC...THE MAIN AREA OF LOW PRESSURE SITS OVER THE ERN
BORDER OF ND/SD...WITH A WEAK TROUGH AXIS MAKING ITS WAY ACROSS
THE CWA AND BRINGING A WESTERLY COMPONENT TO THE WINDS...AND A
COOL FRONT SITUATED TO THE NORTH.
FOR THE DAYTIME HOURS TODAY...CONTINUED WITH THE DRY FORECAST
ACROSS THE CWA...THOUGH THE 06Z NAM IS TRYING TO HINT AT SOME
PRECIP THIS AFTERNOON IN THE FAR NORTH...BUT NOT MUCH SUPPORT FOR
THAT. MAIN STORY FOR TODAY LIES WITH THE ABOVE MENTIONED UPPER
LEVEL DISTURBANCE...AND AS IT CONTINUES TO SHIFT INTO THE UPPER
MIDWEST REGION THROUGH THE DAY AM EXPECTING A REINFORCING COOL
FRONT TO PUSH SOUTH THROUGH THE CWA. THIS WILL BRING MORE
NORTHERLY WINDS TO THE CWA...ALREADY BY MID/LATE MORNING. EVEN
WITH THE FRONT PUSHING THROUGH...NOT SEEING A SIGNIFICANT CHANGE
OF THE AIRMASS IN PLACE...SO EXPECTING ANOTHER VERY WARM DAY.
DIDNT MAKE MAJOR CHANGES TO THE INHERITED HIGHS...WHICH REMAIN
ABOVE GUIDANCE...BUT GUIDANCE ALSO DID NOT HANDLE YESTERDAYS TEMPS
VERY WELL. MID/UPPER 80S IN THE NORTH WITH MID/UPPER 90S IN THE
SOUTH LOOK POSSIBLE AGAIN TODAY FOR AFTERNOON HIGH
TEMPERATURES...BUT ARE CURRENTLY FORECAST TO FALL SHORT OF THE
RECORDS IN THE TRI-CITIES...WHICH ARE IN THE LOW 90S. FORECAST
SOUNDINGS FROM AROUND THE CWA SHOW MIXING POTENTIAL UPWARDS OF AT
LEAST 750MB THIS AFTERNOON...AND WOULD EXPECT SOME GUSTY WINDS AT
TIMES. ALSO LOWERED DEWPOINTS SOME...WHICH GIVES RH VALUES
NEAR/BELOW 20 PERCENT...BUT NO FIRE WEATHER HEADLINES WILL BE
NEEDED WITH THE FUELS BEING UNFAVORABLE FOR LARGE FIRE GROWTH.
LOOKING AT TONIGHT...KEPT THE EVENING HOURS DRY AND ALSO KEPT SOME
SMALL POPS IN AFTER MIDNIGHT...BUT CONFIDENCE IN PRECIP
OCCURRING IS CERTAINLY NOT HIGH AT THIS POINT. DID NOT WANT TO
COMPLETELY REMOVE POPS...THOUGH IT WAS CONSIDERED...AS THERE IS
STILL SOME SUPPORT WITH A WEAK WAVE POTENTIALLY MOVING
THROUGH...ALONG WITH A MID LEVEL FRONT SETTING UP ALONG THE FAR
W/SW PORTIONS OF THE CWA. INSTEAD JUST TRIMMED BACK THE EASTERN
EXTENT OF THE INHERITED POPS...KEEPING ANY CHANCES WEST OF HIGHWAY
281.
AS WE GET INTO THURSDAY/FRIDAY...WILL SEE INCREASING PRECIPITATION
CHANCES AS AN UPPER LEVEL LOW PRESSURE SYSTEM AFFECTS THE PLAINS.
AT 12Z THURSDAY...MODELS NOT IN TOO BAD OF AGREEMENT...SHOWING
THE 500MB LOW OVER SRN CAL...WHILE A 700MB SHORTWAVE DISTURBANCE
OUT AHEAD OF THIS LOW IS MOVING OUT OF THE ROCKIES. THROUGH THE
DAYTIME HOURS...SURFACE LOW PRESSURE BECOMES BETTER ORGANIZED OVER
WRN COLORADO...CAUSING WINDS TO BECOME EASTERLY...AND ARE EXPECTED
TO INCREASE THROUGH THE DAY AS THE PRESSURE GRADIENT TIGHTENS UP
ACROSS THE REGION. THIS SHORTWAVE DISTURBANCE IS EXPECTED TO BRING
INCREASED CHANCES THROUGH THE DAY...WITH HIGHER POPS CONTINUING ON
OVERNIGHT AND THROUGH THE REMAINDER OF THE SHORT TERM
PERIOD...DRIVEN BY THE UPPER LEVEL LOW PRESSURE SYSTEM FINALLY
MAKING ITS WAY OUT OF THE SWRN CONUS AND THROUGH THE PLAINS. MAY
SEE A BIT OF A BREAK DURING THE AFTERNOON HOURS ON THURSDAY...BUT
LATER IN THE AFTERNOON/EVENING...AM EXPECTING CONVECTION TO
DEVELOP ACROSS THE HIGH PLAINS ALONG THE SFC DRYLINE. THIS
ACTIVITY EXPECTED TO THEN SHIFT EAST ACROSS THE CWA OVERNIGHT AS
THE MID/UPPER LEVEL SYSTEMS MOVE IN...ALSO AIDED BY AN INCREASING
S/SERLY LLJ. ACROSS THE SWRN HALF OF THE CWA/AREAS NOT AS IMPACTED
BY EARLIER PRECIP AND CLOUDS...EXPECTING A NARROW BAND OF
GREATER INSTABILITY TO DEVELOP OUT AHEAD OF THE DRY LINE...WHICH
LOOKS TO AT LEAST CLIP A PORTION OF THE CWA...THOUGH LATEST MODELS
HAVE THE HIGHEST AXIS SW OF THE CWA. THE BETTER CHANCES FOR
STRONG/SEVERE WEATHER LOOKS TO BE W/SW OF THE CWA WITH THE BETTER
INSTABILITY...BUT IT CERTAINLY CANT BE RULED OUT OVERNIGHT AS THAT
ACTIVITY SHIFTS EAST THROUGH THE CWA. EASTERLY WINDS WILL CONTINUE
TO BE BREEZY THROUGH THE EVENING/OVERNIGHT HOURS AS THE MAIN SFC
LOW SITS WEST OF THE CWA...SPEEDS PUSHING 25-30 MPH NOT OUT OF THE
QUESTION.
BY 12Z FRIDAY...MODELS SHOWING A MORE VERTICALLY STACKED LOW...BUT
SLIGHT DIFFERENCES STILL EXIST WITH ITS EXACT LOCATION...AND
PATH THROUGH THE REGION. MODELS AT 12Z VARY WITH THE LOW BEING
ANYWHERE FROM THE PANHANDLE OF NEB /NAM/ TO SERN COL /ECMWF/. THIS
VARIATION CONTINUES THROUGH THE DAYTIME HOURS...WITH THE NAM
REMAINING THE NORTHERN MOST SOLUTION...THE GFS PUSHES THE CENTER
OF THE MID/UPPER LOW RIGHT OVER THE NWRN HALF OF THE CWA...AND THE
ECMWF IS A TOUCH FURTHER SOUTH AND SLOWER. WASNT COMFORTABLE
MAKING SIGNIFICANT CHANGES TO THE INHERITED POPS /JUST SOME TIMING
ADJUSTMENTS/...WHICH WERE ALREADY IN THE LIKELY RANGE THURSDAY
NIGHT/FRIDAY...FELT THAT HANDLES THINGS FINE AT THIS POINT. WHILE
INSTABILITY LOOKS TO DECREASE THROUGH THE DAY...THERE IS STILL
SOME PRESENT SO KEPT A THUNDER MENTION GOING THROUGH THE DAY...AND
WILL HAVE TO KEEP AN EYE ON WHICH MODEL TURNS OUT BEING RIGHT WITH
THE SFC LOW AND ACCOMPANYING BOUNDARIES. IF THE COMBO OF THESE
FEATURES END UP RIGHT OVER THE CWA...WOULDNT NEED HIGH
INSTABILITY VALUES OR BIG THUNDERSTORMS TO POTENTIALLY MAKE FOR AN
INTERESTING PERIOD AT SOME POINT FRIDAY. FOR FRIDAY
EVENING/OVERNIGHT...MAIN CHANGE TO THE POPS WAS TO TREND BACK THE
SWRN PORTIONS OF THE CWA...WITH MODELS NOT IN TOO BAD OF AGREEMENT
SHOWING THE SYSTEM EXITING BY 12Z SATURDAY.
HIGH TEMPERATURES THURSDAY AND FRIDAY ARE TRICKY...AND WILL BE
DEPENDENT ON THE AMOUNT OF CLOUD COVER/PRECIPITATION IN THE AREA.
THURSDAY IS FORECAST TO REACH GENERALLY FROM NEAR 70 IN THE NORTH
TO THE MID/UPPER 70S IN THE SOUTH...WHILE FRIDAY WILL SEE MORE
OF A GRADIENT AS CLOUDS/PRECIP AFFECT THE NORTH...AND THE S/SW
COULD SEE A LITTLE SUN AND SOME WARMER AIR BUILD BACK IN.
CURRENTLY HAVE HIGHS IN THE LOWER 50S IN THE NEAST TO NEAR 70 IN
THE SOUTH.
LONG TERM...SATURDAY THROUGH TUESDAY. AFTER A WEEK THAT FEATURED
RECORD HIGH TEMPERATURES...THIS WEEKEND WILL BE MUCH COOLER AND
EVEN BELOW NORMAL. IN ADDITION...THERE WILL BE PERIODIC SLIGHT
CHANCES OF RAIN.
SATURDAY AND SUNDAY...COOLER AIR WILL FILTER DOWN INTO THE CENTRAL
PLAINS ON SATURDAY BEHIND THE DEPARTING UPPER LEVEL SHORTWAVE.
TEMPERATURES WILL BE SLOW TO RECOVER ON SUNDAY. EXPECT BOTH
SATURDAY AND SUNDAY WILL SEE HIGHS STUCK IN THE 50S WHERE AS
NORMAL HIGHS ARE NOW IN THE MID 60S FOR THIS TIME OF YEAR. THERE
WILL BE AT LEAST SOME CHANCE OF RAIN ACROSS PORTIONS OF OUR
FORECAST AREA ON SATURDAY AND SUNDAY...BUT THESE SHOULD ONLY BE
SLIGHT CHANCES AND AM NOT EXPECTING ANY KIND OF ALL DAY RAIN OUT
AT THIS TIME.
MONDAY AND TUESDAY...THERE WILL BE RETURN SOUTHERLY FLOW ON
MONDAY AND THUS MODERATING TEMPERATURES. HIGHS ON MONDAY SHOULD BE
BACK INTO THE 60S WITH PERHAPS HIGHS AROUND 70 BY TUESDAY. THE
RETURN SOUTHERLY FLOW WILL ALSO ALLOW FOR MOISTURE RICH AIR TO
SLIDE INTO OUR REGION RESULTING IN INCREASING SHOWER AND
THUNDERSTORM CHANCES. THE BETTER CHANCES FOR THESE SHOWERS AND
THUNDERSTORMS SEEM TO BE IN THE MONDAY NIGHT INTO TUESDAY TIME
FRAME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
UPDATE/AVIATION...PFANNKUCH
SHORT TERM...ADO
LONG TERM...WESELY
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1248 PM CDT WED APR 25 2012
.UPDATE...
AVIATION DISCUSSION UPDATED FOR 18Z TAF ISSUANCE.
FORECAST FOR TODAY ON TRACK AND DO NOT ANTICIPATE ANY SIGNIFICANT
CHANGES AT THIS TIME. MID AND HIGH LEVEL CLOUDS WILL PASS THROUGH
THE REGION TODAY WITH BREEZY NORTHWEST WINDS. HIGHS WILL RISE INTO
THE 70S TO LOW 80S...WITH THE WARMEST READINGS ACROSS SOUTHERN
SOUTH DAKOTA.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
FORECAST CHALLENGES INCLUDE TEMPERATURES AND PRECIPITATION
COVERAGE/AMOUNTS THURSDAY THROUGH FRIDAY.
CURRENTLY...BASED OFF SURFACE PRESSURE ANALYSIS AND RUC THERMAL
ADVECTION PROGS...IT APPEARS THERE ARE TWO COLD FRONTS PASSING
THROUGH THE CWA OVER THE NEXT 12 TO 18 HOURS. THE FIRST
FRONT...APPX HALF WAY THROUGH THE CWA...IS A RATHER WEAK BOUNDARY
MAINLY A WIND SHIFT FROM SWRLY TO NWRLY...BUT THERE IS SOME VERY
SUBTLE WEAK LOW LEVEL CAA ALREADY OCCURRING BEHIND THIS WIND
SHIFT. THE STRONGER MORE NOTABLE COLD FRONT IS LOCATED BACK OVER
WESTERN AND CENTRAL NORTH DAKOTA AND SHOULD BE SWINGING SOUTH
THROUGH THIS CWA LATER TODAY. TEMPERATURES RIGHT NOW ARE IN THE
50S AND 60S ACROSS THE CWA...A GOOD 20 TO 30 DEGREES ABOVE NORMAL
LOWS. THE EARLIER RAIN SHOWERS AND THUNDERSTORMS HAVE CLEARED THE
CWA...LEAVING JUST SOME SCATTERED/BROKEN MID AND HIGH CLOUDS
AROUND OVER THE CWA.
DIFFICULT TO SAY IF THERE IS ACTUALLY ANOTHER SHORT-WAVE SET TO
WORK THROUGH THE CWA THIS AFTERNOON/EVENING BRINGING WITH IT A
SMALL CHANCE FOR PRECIPITATION. THE 00Z GFS THINKS THERE IS...BUT
IT IS THE ONLY MODEL PAINTING LIGHT QPF OVER THE CWA LATER THIS
EVENING. SO...OPTED TO KEEP TODAY/TONIGHT DRY. BEFORE THE STRONGER
COLD FRONT PASSES THROUGH THIS CWA LATE THIS AFTERNOON THROUGH
LATE TONIGHT...TEMPERATURES SHOULD RECOVER BACK UP INTO THE 70S
AND 80S...PER 925HPA THERMAL PROGS IN THE UPPER TEENS TO LOWER 20S
CELSIUS THIS AFTERNOON.
THURSDAY THROUGH FRIDAY...ALL THE MODELS CONTINUE TO AGREE OVERALL
IN TIMING AND TRACK OF LONGWAVE TROF ENERGY SET TO WORK INTO THE
CENTRAL/NORTHERN PLAINS...BEFORE RUNNING INTO AN UPPER LEVEL
STEERING FLOW BRICK WALL. KEEPING THE CATEGORICAL POPS FOR
THURSDAY NIGHT AND FRIDAY...AND JUST KEPT SOME CHANCE POPS ACROSS
THE WESTERN THIRD OF FORECAST ZONES ON THURSDAY...MAINLY FOR LATE
IN THE AFTERNOON ON THURSDAY. BUFKIT ANALYSIS KEEPS P-TYPE ALL
RAIN...ALTHOUGH LATE IN THE DAY ON FRIDAY...THE NAM MODEL BECOMES
MUCH MORE AGGRESSIVE AT DROPPING MUCH OF THE ATMOSPHERIC COLUMN
BELOW ZERO CELSIUS. THE LOWEST 1000 TO 1500 FT AGL APPEAR TO
REMAIN ABOVE FREEZING...WHICH STILL EFFECTIVELY MELTS
HYDRO-METEORS. THE GFS LOOKS SIMILAR...BUT KEEPS A DEEPER BOTTOM
OF THE ATMOSPHERIC COLUMN ABOVE FREEZING. STILL LOOKS LIKE NEAR TO
BELOW NORMAL TEMPERATURES WILL PREVAIL THURSDAY THROUGH FRIDAY.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
AN UPPER LEVEL TROUGH WILL BE OVER THE ROCKIES TO START THE
PERIOD...WITH SHORTWAVE ENERGY BEING SHUNTED NORTHWARD OVER THE
UPPER MIDWEST THROUGH THE WEEKEND. THE UPPER FLOW THEN BECOMES
NEARLY ZONAL ON MONDAY BEFORE A SHORTWAVE TROUGH TRACKS ACROSS THE
PLAINS ON TUESDAY.
AT THE SURFACE...AN ELONGATED TROUGH OF LOW PRESSURE WILL EXTEND
FROM WESTERN CANADA TO TEXAS WITH PRECIPITATION ONGOING OVER THE
CWA WHEN THE PERIOD STARTS. THE PRECIPITATION LOOKS TO CONTINUE
INTO THE DAY SATURDAY BEFORE COMING TO AN END AS HIGH PRESSURE
DROPS SOUTH OVER THE NORTHERN PLAINS AND GREAT LAKES...AND WILL
STICK WITH HIGH CHANCE TO LIKELY POPS BOTH FRIDAY NIGHT INTO EARLY
SATURDAY. AS THE HIGH PUSHES OFF TO THE EAST...THE REMAINDER OF
THE PERIOD BECOMES SOMEWHAT UNSTABLE AS ANOTHER LOW PRESSURE
TROUGH DEVELOPS TO THE WEST AND BRINGS POTENTIAL ROUNDS OF
PRECIPITATION TO THE CWA SUNDAY THROUGH THE DAY TUESDAY. WITH THE
UNCERTAINTY IN TIMING...WILL KEEP POPS IN THE SCHC/CHC RANGE FOR
NOW.
TEMPERATURES WILL BE COOL TO START THE PERIOD...A GOOD 10 DEGREES
OR SO BELOW NORMAL FOR HIGHS ON SATURDAY. WILL THEN SEE A GRADUAL
WARMING TREND THROUGH THE PERIOD AS H85 TEMPS RISE FROM AROUND
ZERO EARLY SATURDAY TO APPROACHING THE LOWER TEENS BY TUESDAY.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS ARE EXPECTED TO PREVAIL ACROSS ALL TAF SITES THE
NEXT 24 HOURS. SCT TO BKN MID TO HIGH CLOUDS WILL CONTINUE TO
STREAM OVERHEAD THE REMAINDER OF TODAY THRU TONIGHT AND INTO EARLY
TOMORROW. THICKER MID/HIGH CLOUDS EXPECTED OVER THE KPIR AND KMBG
TERMINALS TOWARD THE END OF THE TAF PERIOD. WINDS WILL REMAIN
GUSTY FROM THE NORTH TO NORTHWEST THRU EARLY EVENING BEFORE
DIMINISHING. THEY WILL BECOME MORE NORTHEAST TO EASTERLY OVERNIGHT
INTO TOMORROW MORNING REMAINING IN THE 10 TO 15 KT RANGE.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...DORN
LONG TERM...PARKIN
AVIATION...VIPOND
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1129 AM CDT WED APR 25 2012
.UPDATE...REST OF TODAY
FORECAST FOR TODAY ON TRACK AND DO NOT ANTICIPATE ANY SIGNIFICANT
CHANGES AT THIS TIME. MID AND HIGH LEVEL CLOUDS WILL PASS THROUGH
THE REGION TODAY WITH BREEZY NORTHWEST WINDS. HIGHS WILL RISE INTO
THE 70S TO LOW 80S...WITH THE WARMEST READINGS ACROSS SOUTHERN
SOUTH DAKOTA.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
FORECAST CHALLENGES INCLUDE TEMPERATURES AND PRECIPITATION
COVERAGE/AMOUNTS THURSDAY THROUGH FRIDAY.
CURRENTLY...BASED OFF SURFACE PRESSURE ANALYSIS AND RUC THERMAL
ADVECTION PROGS...IT APPEARS THERE ARE TWO COLD FRONTS PASSING
THROUGH THE CWA OVER THE NEXT 12 TO 18 HOURS. THE FIRST
FRONT...APPX HALF WAY THROUGH THE CWA...IS A RATHER WEAK BOUNDARY
MAINLY A WIND SHIFT FROM SWRLY TO NWRLY...BUT THERE IS SOME VERY
SUBTLE WEAK LOW LEVEL CAA ALREADY OCCURRING BEHIND THIS WIND
SHIFT. THE STRONGER MORE NOTABLE COLD FRONT IS LOCATED BACK OVER
WESTERN AND CENTRAL NORTH DAKOTA AND SHOULD BE SWINGING SOUTH
THROUGH THIS CWA LATER TODAY. TEMPERATURES RIGHT NOW ARE IN THE
50S AND 60S ACROSS THE CWA...A GOOD 20 TO 30 DEGREES ABOVE NORMAL
LOWS. THE EARLIER RAIN SHOWERS AND THUNDERSTORMS HAVE CLEARED THE
CWA...LEAVING JUST SOME SCATTERED/BROKEN MID AND HIGH CLOUDS
AROUND OVER THE CWA.
DIFFICULT TO SAY IF THERE IS ACTUALLY ANOTHER SHORT-WAVE SET TO
WORK THROUGH THE CWA THIS AFTERNOON/EVENING BRINGING WITH IT A
SMALL CHANCE FOR PRECIPITATION. THE 00Z GFS THINKS THERE IS...BUT
IT IS THE ONLY MODEL PAINTING LIGHT QPF OVER THE CWA LATER THIS
EVENING. SO...OPTED TO KEEP TODAY/TONIGHT DRY. BEFORE THE STRONGER
COLD FRONT PASSES THROUGH THIS CWA LATE THIS AFTERNOON THROUGH
LATE TONIGHT...TEMPERATURES SHOULD RECOVER BACK UP INTO THE 70S
AND 80S...PER 925HPA THERMAL PROGS IN THE UPPER TEENS TO LOWER 20S
CELSIUS THIS AFTERNOON.
THURSDAY THROUGH FRIDAY...ALL THE MODELS CONTINUE TO AGREE OVERALL
IN TIMING AND TRACK OF LONGWAVE TROF ENERGY SET TO WORK INTO THE
CENTRAL/NORTHERN PLAINS...BEFORE RUNNING INTO AN UPPER LEVEL
STEERING FLOW BRICK WALL. KEEPING THE CATEGORICAL POPS FOR
THURSDAY NIGHT AND FRIDAY...AND JUST KEPT SOME CHANCE POPS ACROSS
THE WESTERN THIRD OF FORECAST ZONES ON THURSDAY...MAINLY FOR LATE
IN THE AFTERNOON ON THURSDAY. BUFKIT ANALYSIS KEEPS P-TYPE ALL
RAIN...ALTHOUGH LATE IN THE DAY ON FRIDAY...THE NAM MODEL BECOMES
MUCH MORE AGGRESSIVE AT DROPPING MUCH OF THE ATMOSPHERIC COLUMN
BELOW ZERO CELSIUS. THE LOWEST 1000 TO 1500 FT AGL APPEAR TO
REMAIN ABOVE FREEZING...WHICH STILL EFFECTIVELY MELTS
HYDRO-METEORS. THE GFS LOOKS SIMILAR...BUT KEEPS A DEEPER BOTTOM
OF THE ATMOSPHERIC COLUMN ABOVE FREEZING. STILL LOOKS LIKE NEAR TO
BELOW NORMAL TEMPERATURES WILL PREVAIL THURSDAY THROUGH FRIDAY.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
AN UPPER LEVEL TROUGH WILL BE OVER THE ROCKIES TO START THE
PERIOD...WITH SHORTWAVE ENERGY BEING SHUNTED NORTHWARD OVER THE
UPPER MIDWEST THROUGH THE WEEKEND. THE UPPER FLOW THEN BECOMES
NEARLY ZONAL ON MONDAY BEFORE A SHORTWAVE TROUGH TRACKS ACROSS THE
PLAINS ON TUESDAY.
AT THE SURFACE...AN ELONGATED TROUGH OF LOW PRESSURE WILL EXTEND
FROM WESTERN CANADA TO TEXAS WITH PRECIPITATION ONGOING OVER THE
CWA WHEN THE PERIOD STARTS. THE PRECIPITATION LOOKS TO CONTINUE
INTO THE DAY SATURDAY BEFORE COMING TO AN END AS HIGH PRESSURE
DROPS SOUTH OVER THE NORTHERN PLAINS AND GREAT LAKES...AND WILL
STICK WITH HIGH CHANCE TO LIKELY POPS BOTH FRIDAY NIGHT INTO EARLY
SATURDAY. AS THE HIGH PUSHES OFF TO THE EAST...THE REMAINDER OF
THE PERIOD BECOMES SOMEWHAT UNSTABLE AS ANOTHER LOW PRESSURE
TROUGH DEVELOPS TO THE WEST AND BRINGS POTENTIAL ROUNDS OF
PRECIPITATION TO THE CWA SUNDAY THROUGH THE DAY TUESDAY. WITH THE
UNCERTAINTY IN TIMING...WILL KEEP POPS IN THE SCHC/CHC RANGE FOR
NOW.
TEMPERATURES WILL BE COOL TO START THE PERIOD...A GOOD 10 DEGREES
OR SO BELOW NORMAL FOR HIGHS ON SATURDAY. WILL THEN SEE A GRADUAL
WARMING TREND THROUGH THE PERIOD AS H85 TEMPS RISE FROM AROUND
ZERO EARLY SATURDAY TO APPROACHING THE LOWER TEENS BY TUESDAY.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
VFR CONDITIONS WILL PREVAIL TODAY AND TONIGHT WITH SCATTERED TO
BROKEN HIGH CLOUDS AOA 20K FEET STREAMING OVER THE REGION. VSBYS
WILL BE UNRESTRICTED.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...TMT
SHORT TERM...DORN
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 PM CDT WED APR 25 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
338 PM CDT WED APR 25 2012
AT 3 PM...A SURFACE LOW WAS LOCATED JUST WEST OF CHARLES CITY
IOWA. A WARM FRONT EXTENDED SOUTHEAST OF THIS LOW INTO CENTRAL
ILLINOIS...AND A COLD FRONT EXTENDED WEST ACROSS WEST-CENTRAL
IOWA. TEMPERATURES ACROSS WESTERN AND SOUTHERN IOWA HAVE WARMED
WELL INTO THE 80S. THERE WERE EVEN A FEW 90S. MEANWHILE NORTH OF
THE WARM FRONT...THE TEMPERATURES RANGED FROM THE 40S ACROSS
NORTHERN WISCONSIN TO THE 60S ACROSS MUCH OF OUR FORECAST AREA.
ML CAPES HAVE CLIMB UP TO 250 J/KG ACROSS NORTHEAST IOWA AND
SOUTHWEST WISCONSIN WHICH WAS JUST ENOUGH INSTABILITY FOR THE LOW
PRESSURE AREA TO GENERATE A FEW SHOWERS ACROSS THIS AREA. THE
LATEST HRRR AND SPC WRF SHOW THAT THESE SHOWERS WILL MOVE
SOUTHEAST OF THE AREA BY 6 PM. FURTHER TO THE NORTHWEST SOME
ADDITIONAL SHOWERS WERE MOVING EAST SOUTHEAST ACROSS NORTHERN
WISCONSIN. THESE SHOWERS WERE ASSOCIATED WITH A POTENTIAL
VORTICITY ANOMALY MOVING SOUTHEAST ACROSS NORTHERN AND EASTERN
WISCONSIN. THESE SHOWERS HAVE BEEN MAINLY EAST AND NORTH OF TAYLOR
COUNTY...SO JUST WENT DRY THERE FOR TONIGHT.
ON THURSDAY...HIGH PRESSURE WILL NOSE SOUTHWARD INTO THE UPPER
MISSISSIPPI RIVER VALLEY. WITH ABUNDANT SUNSHINE...MUCH OF THE
AREA WILL MIX UP TO AROUND 850 MB. AS THIS OCCURS...DRIER AIR FROM
ALOFT WILL MIX TO THE SURFACE. THIS WILL LOW THE DEW POINTS TO
AROUND 20 NORTH OF THE INTERSTATE 94 CORRIDOR...AND IN THE LOWER
AND MID 20S ACROSS THE REMAINDER OF THE AREA. THIS IS ABOUT 3 TO
5 DEGREES LOWER THAN THE MOS DEW POINTS.
ON THURSDAY NIGHT...THE DEW POINTS WILL REMAIN RATHER DRY. THIS
WILL ALLOW THE TEMPERATURES TO DROP OFF RATHER RAPIDLY ACROSS
CENTRAL AND NORTH-CENTRAL WISCONSIN. LOW TEMPERATURES ACROSS THIS
AREA WILL LIKELY FALL INTO THE MID AND UPPER 20S. WITH TEMPERATURE
AND DEW POINT SPREADS GREATER THAN 8F...CONCERNED THAT THERE WILL
BE NO FROST DEVELOPMENT. HOWEVER THESE TEMPERATURES WILL STILL BE
COLD ENOUGH TO CAUSE SOME DAMAGE TO UNPROTECTED FRUIT CROPS AND
COLD-SENSITIVE FLOWERS. MEANWHILE FURTHER WEST AND SOUTH...THERE
WILL INCREASE IN THE CLOUD COVER FROM THE LATE EVENING INTO THE
OVERNIGHT. THIS WILL TEMPER THE POTENTIAL FALL IN THE TEMPERATURES
AND FROST DEVELOPMENT IN THOSE AREAS.
FROM FRIDAY INTO SATURDAY...A LONG WAVE TROUGH WILL BE DIGGING
INTO THE WESTERN CONUS. AS THIS OCCURS...THE RIDGE WILL BE
AMPLIFYING ACROSS THE CENTRAL UNITED STATES AND CANADIAN PRAIRIES.
THIS PATTERN SHIFT STARTED TO DEVELOP LAST NIGHT AND CONTINUED
INTO TODAY. AS A RESULT...THE STRONG 800 TO 500 MB FRONTOGENESIS
HAS MOVED BACK NORTHWARD INTO SOUTHEAST MINNESOTA...NORTHEAST
IOWA...AND SOUTHERN HALF OF WISCONSIN. DUE TO THIS...THE
PRECIPITATION PROBABILITIES WERE RAISED AND MOVED NORTH. 25.12Z
GFS AND NAM/WRF BUFKIT SOUNDINGS SUGGEST THAT THE COLUMN WILL BE
COLD ENOUGH AND THERE WILL BE THE INTRODUCTION OF ICE CRYSTALS AT
TIMES FOR THE RAIN TO CHANGE OVER TO SNOW AT TIMES IN THESE AREAS.
THE 25.12Z ECMWF AND 25.18Z NAM/WRF ALSO SHOWS POSSIBILITY. HOWEVER
IT IS A BIT FURTHER NORTH AND EAST. THIS MAY SHIFT EVEN FURTHER
NORTHWEST IF THE TROUGH IN THE WESTERN CONUS DIGS EVEN MORE. SINCE
THE POSSIBILITY OF SNOW HAS BEEN CONSISTENT FOR THE LAST 3 MODEL
RUN...JUST INTRODUCED A CHANCE OF SNOW AT THIS TIME. IN ADDITION
WITH MORE PRECIPITATION AND CLOUD COVER EXPECTED...HIGH
TEMPERATURES FOR SATURDAY HAD TO BE COOLED A FEW MORE
DEGREES...AND THIS MAY NOT BE ENOUGH YET. THE FORECAST FOR THIS
TIME PERIOD WILL LIKELY REMAIN RATHER FLUENT UNTIL THIS SYSTEM IS
SAMPLED FULLY BY THE UPPER AIR NETWORK ON THURSDAY NIGHT.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
338 PM CDT WED APR 25 2012
ON SATURDAY NIGHT...WE MAY HAVE THE POTENTIAL FOR ANOTHER FROST OR
FREEZE AS A HIGH PRESSURE SYSTEM BUILD ACROSS THE REGION. THE MAIN
QUESTION AT THIS TIME IS HOW FAST WILL THE AREA CLEAR OUT AND WHEN
THE WINDS MAY DECOUPLE.
FROM MONDAY NIGHT THROUGH WEDNESDAY...THE 25.12Z MODELS CONTINUE
TO STRUGGLE ON THE TIMING OF A LONG WAVE TROUGH MOVING OUT OF THE
CENTRAL PLAINS. THE ECMWF IS ABOUT 12 HOURS SOONER THAN THE GFS
AND HAS ITS PRECIPITATION CHANCES RUNNING FROM MONDAY NIGHT INTO
TUESDAY. WITH THE MODELS CONTINUING TO STRUGGLE WITH ITS TIMING
JUST STAYED WITH THE ALL BLEND TIMING FOR NOW.
&&
.AVIATION...THROUGH 18Z THURSDAY
1248 PM CDT WED APR 25 2012
MAIN FORECAST CONCERNS ARE ISOLATED SHOWERS AND THUNDERSTORMS
POSSIBILITIES FROM 18Z WEDNESDAY TO 00Z THURSDAY...THEN THE POTENTIAL
FOR MVFR CEILINGS AT BOTH TAF SITES AFTER 03Z THURSDAY. LATEST 17Z
SURFACE ANALYSIS SHOWING LOW PRESSURE OVER NORTHERN IOWA AND
SOUTHERN MINNESOTA. THE LATEST 25.15Z RUC...25.12Z NAM/GFS
INDICATING SURFACE LOW TO PUSH SOUTHEAST INTO CENTRAL ILLINOIS
TONIGHT. THE DETERMINISTIC MODELS ARE SHOWING WEAK MOISTURE
TRANSPORT AND CONVERGENCE IN ASSOCIATION WITH THE SURFACE LOW THIS
AFTERNOON. CANNOT RULE OUT THE POSSIBILITY OF ISOLATED SHOWERS OR
THUNDERSTORMS ACROSS THE REGION THIS AFTERNOON...WITH THE
SHOWER/THUNDERSTORM ACTIVITY REMAINING ISOLATED...WILL NOT
MENTION IN THE RST AND LSE TAFS. SURFACE HIGH PRESSURE OVER SOUTHERN
CANADA BUILDS INTO THE REGION AFTER 00Z THURSDAY. THE
DETERMINISTIC MODELS ARE INDICATING MOISTURE AT ABOUT 2000-3000
FEET TO DRIFT OVER THE AREA AFTER 03Z THURSDAY. WITH CONFIDENCE
BEING LOW IN EXPANDING CLOUD DECK...OVER NORTHERN WISCONSIN...SOUTHWARD
INTO TAF SITES...HAVE INTRODUCED SCATTERED CLOUDS IN THIS RANGE OF
CLOUD HEIGHTS AT BOTH TAF SITES. AS SURFACE HIGH PRESSURE BUILDS
SOUTH...PRESSURE GRADIENT TIGHTENS AND WIND SPEEDS FROM THE NORTH
INCREASE TO 12 TO 15 KNOTS WITH GUSTS POSSIBLY TO AROUND 20 KNOTS
AT BOTH RST AND LSE TAF SITES AFTER 09Z THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
237 PM CDT WED APR 25 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...DTJ