Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/27/12
AREA FORECAST DISCUSSION...UPDATED
NWS PUEBLO CO
526 PM MDT THU APR 26 2012
.AVIATION...THERE IS APPROXIMATELY A 50 PERCENT CHANCE OF A THUNDERSTORM
AFFECTING THE TAF SITES BETWEEN NOW AND 06Z. WIDELY SCT SHOWERS
AND ISOLD TS CONTINUE TO MOVE FROM THE SW TO NE AT APPROXIMATELY
30 KT. SHOWERS AND TS WILL PRODUCE OCCASIONAL STRONG WIND GUSTS
FROM THE W-SW...WITH GUSTS TO 40-50 KT POSSIBLE. BRIEF IFR-MVR
CONDITIONS ARE POSSIBLE...ALONG WITH SMALL HAIL. STRONGER STORMS
WILL BE POSSIBLE E OF THE I-25 CORRIDOR THIS EVENING. STORMS COULD
CONTINUE TO DEVELOP E AND N OF KPUB-KCOS AS LATE AS 06-09Z.
NOTE THAT WINDS WILL BE QUITE ERRATIC THIS EVENING AT KPUB AND
KCOS...AS LOW LEVEL WINDS ARE FROM THE E-SE WHILE STORMS CONTINUE
TO TRANSFER W-SW WINDS TO THE SURFACE. SO...EVEN AWAY FROM
STORMS...WINDS WILL BE QUITE VARIABLE THIS EVE. ROSE
&&
.PREV DISCUSSION... /ISSUED 205 PM MDT THU APR 26 2012/
SHORT TERM...
(TONIGHT AND FRIDAY)
..MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE POTENTIAL FOR
PORTIONS OF THE SOUTHEAST PLAINS THROUGH THE OVERNIGHT HOURS...
COMPACT CLOSED LOW CIRCULATION ACROSS AZ WILL CONTINUE TO LIFT TO
THE NORTHEAST ACROSS SOUTHERN AND SOUTHEAST COLORADO BETWEEN 06Z AND
12Z. SE SFC WINDS HAVE ADVECTED LOWER 50 DEW POINTS INTO BACA
COUNTY...WITH 40S ALONG THE ARKANSAS RIVER TO THE NORTH.
MEANWHILE...SOUTHWEST WINDS HAVE DROPPED DEW POINTS INTO THE 20S
ACROSS THE HIGH VALLEYS...WITH DEW POINTS DROPPING ACROSS THE NRN
RATON MESA AND PALMER DIVIDE AS DRY LINE TAKES SHAPE. MODELS STILL
PAINT THE SCENARIO OF A COUPLE OF WAVES OF CONVECTION DEVELOPING
ACROSS THE MOUNTAINS AND MOVING OFF INTO THE SOUTHEAST PLAINS.
FIRST WAVE IS CURRENTLY DEVELOPING ACROSS THE MTS NOW...AND EXPECT
CONVECTION TO DEVELOP ALONG THE SFC TROF/DRY LINE BY 20-21Z. SPC
MESO ANALYSIS CURRENTLY SHOWING CAPES OF AROUND 1000 TO NEAR 1500
J/KG ACROSS THE SOUTHEAST PLAINS WITH DEEP LAYER SHEARS RUNNING
AROUND 40-50 KTS. HRRR...RUC13...AND NAM12 MIX THE DEW POINTS OUT
ALONG THE I-25 CORRIDOR BACK INTO THE 30S...THOUGH HANG TOUGH WITH
THE 40S-LOWER 50 DEW POINTS ACROSS THE SOUTHEAST COUNTIES OF
KIOWA...BENT...PROWERS...AND BACA...AS WELL AS EASTERN PORTIONS OF
CROWLEY...OTERO...AND LAS ANIMAS COUNTIES. INITIALLY LCLS WILL START
OUT RATHER HIGH...WITH THE PROXY T/TD SPREADS RUNNING AROUND 30
DEGREES ACROSS THIS REGION. HOWEVER...WITH THE APPROACH OF THE
UPPER TROF...STRENGTHENING SOUTHEASTERLY WINDS WILL ADVECT 40 DEW
POINTS BACK INTO THE NRN I-25 CORRIDOR...WITH 50S TO LOWER 60 DEW
POINTS ACROSS THE SOUTHEAST PLAINS. COUPLED WITH COOLING TEMPS
ALOFT WITH INCOMING SYSTEM...THIS SHOULD AMP UP CAPE VALUES TO
BETWEEN 1500-2500 J/KG...WITH HIGHEST VALUES ACROSS BACA COUNTY BY
06Z. HELICITIES INCREASE TO 500+ M2/S2 BY 06Z WITH FORCING FROM THE
SYSTEM LIKELY TO WEAKEN OR BREAK THROUGH WHATEVER CAP REMAINS.
THUS...SEVERE WEATHER EVENT LOOKS TO START OUT AS A LARGE HAIL...AND
DAMAGING WIND SCENARIO THIS AFTERNOON...AND EVOLVE TO INCLUDE AN
ISOLATED TORNADO POTENTIAL AFTER 9 PM ACROSS THE FAR EASTERN
COUNTIES. THIS ATYPICAL LATE NIGHT TORNADO THREAT FOR THIS REGION
SHOULD LAST UNTIL AROUND 2 AM. STILL THINK THE MAIN THREAT AREA
WILL EXTEND EAST OF A LINE FROM LIMON...TO LA JUNTA...TO KIM.
THOUGH IF RUC IS CORRECT IN SPREADING 40 TO LOWER 50 DEW POINTS BACK
WESTWARD INTO THE I-25 CORRIDOR AFTER THE FIRST ROUND OF AFTERNOON
THUNDERSTORMS...THEN PLENTY OF MOISTURE WILL BE AVAILABLE TO BOOST
CAPES UP FOR THE I-25 CORRIDOR FROM AROUND PUB NORTHWARD FOR THE 2ND
ROUND OF THUNDERSTORMS WHICH SPREADS OFF THE SOUTHEAST MOUNTAINS
DURING THE LATE EVENING. IF THIS OCCURS...THEN HAIL TO NEAR 1 INCH
IN DIAMETER ALONG WITH DAMAGING WINDS MAY BE POSSIBLE FOR KCOS AND
KPUB AS WELL. WILL CONTINUE TO MONITOR THIS POTENTIAL AS SCENARIO
EVOLVES.
ACROSS THE REMAINDER OF THE AREA...WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS THIS AFTERNOON WITH
SNOW LEVELS DROPPING ACROSS THE MOUNTAINS DURING THE EVENING WHEN
BEST FORCING WITH UPPER LEVEL SYSTEM MOVES THROUGH. COULD SEE
ANYWHERE FROM 2 TO 6 INCHES OF SNOW ACROSS THE HIGHER PEAKS...WITH
MAJORITY OF SNOWFALL ABOVE 10KFT.
PRECIPITATION WILL LIFT OFF TO THE NORTHEAST WITH THE PARENT UPPER
LOW ON FRIDAY WITH PRECIPITATION TAILING OFF ACROSS THE
OROGRAPHICALLY FAVORED NORTHWEST FACING SLOPES OF THE SAWATCH AND
MOSQUITOS IN THE MORNING. COULD ALSO SEE A PERIOD OF WRAP AROUND
PCPN ACROSS THE SOUTHEAST PLAINS DURING THE EARLY MORNING...BUT THIS
SHOULD DIMINISH BY AFTERNOON. OTHERWISE...COOLER TEMPERATURES FOR
FRIDAY...THOUGH WITH GUSTY NORTHWEST TO WEST WINDS BEHIND THE
DEPARTING SYSTEM...DEEP MIXING WILL OFFSET THE COOLING ALOFT SOME TO
STILL YIELD TEMPS IN THE 70S. -KT
LONG TERM...
(FRIDAY NIGHT THROUGH THURSDAY)
FRIDAY NIGHT AND SATURDAY NIGHT...CLOSED UPPER LOW OVER NORTHWEST
WYOMING EARLY FRIDAY EVENING MEANDERS INTO THE WESTERN DAKOTAS
THROUGH SATURDAY NIGHT. AT THE SURFACE...UPSLOPE FLOW CONTINUES ON
THE SOUTHEAST CO PLAINS. NAM BREAKS OUT PRECIPITATION ALONG THE
SOUTHEAST MOUNTAINS SATURDAY EVENING...BUT THEN PRECIPITATION AREAS
SHIFT INTO NORTHEAST COLORADO AND FAR SOUTHEASTERN CO. GFS DOESN`T
HAVE MUCH QPF OVER THE MOUNTAINS...BUT HIGHLIGHTS NORTHEAST AND FAR
SOUTHEAST CORNER OF THE STATE LATE SATURDAY EVENING. GIVEN THE
UPSLOPE FLOW...COOL AIR ALOFT AND STEEP LAPSE RATES...KEPT SOME LOW
POPS IN ALONG THE MOUNTAINS AND SPREAD EASTWARD ONTO THE PLAINS
SATURDAY NIGHT. TEMPERATURES SATURDAY SHOULD BE FAIRLY COOL. KEPT
THE PLAINS IN THE MID 50S TO MID 60S FOR HIGHS DESPITE A LARGE
SPREAD IN THE GUIDANCE HIGHS.
SUNDAY AND SUNDAY NIGHT...GFS/ECMWF STILL BULLISH WITH PRECIPITATION
DEVELOPING ACROSS THE SOUTHEAST PLAINS SUNDAY EVENING WITH SHORT
WAVE MOVING ACROSS SOUTHERN COLORADO. NOT AS COOL WITH HIGHS WARMING
INTO THE LOWER 60S TO LOWER 70S ON THE PLAINS.
MONDAY-TUESDAY...GFS/ECMWF BOTH CONTINUE TO SHOW WEST TO
SOUTHWEST FLOW ALOFT OVER COLORADO EARLY IN THE WORK WEEK AHEAD OF
A STRONGER TROF PROGGED TO MOVE THROUGH WY WEDNESDAY. DESPITE
WARMER AND DRIER AIR MOVING INTO THE FORECAST AREA...MODELS SHOW
SOME MID LEVEL MOISTURE AND A FEW WEAK WAVES TRIGGERING
SHOWERS/THUNDERSTORMS OVER THE MOUNTAINS.
WEDNESDAY-THURSDAY...UPPER LEVEL SHORTWAVE TROF MOVES EAST ACROSS WY
WEDNESDAY. AT THE SURFACE...COLD FRONT MOVES SOUTHEAST THROUGH THE
PLAINS WEDNESDAY NIGHT. DRY LOW LEVEL AIRMASS ON THE PLAINS KEEPS SHOWER
ACTIVITY TIED TO THE MOUNTAINS. TROF AXIS SHIFTS EAST INTO THE
PLAINS STATES WITH RIDGE BUILDING OVER CO ON THURSDAY. 40
AVIATION...
A COUPLE OF ROUNDS OF -TSRA MAY AFFECT KCOS AND KPUB TAF SITES...ONE
LATE THIS AFTERNOON...AND ANOTHER DURING THE EVENING AS THE POTENT
UPPER LEVEL STORM SYSTEM MOVES THROUGH THE REGION. FIRST ROUND OF
THUNDERSTORMS WILL PRODUCE ERRATIC GUSTY WINDS UP TO 40 KTS...ALONG
WITH LIGHTNING AND BRIEF HEAVY RAINFALL. THE 2ND ROUND WHICH WILL
SPREAD OFF THE MTNS INTO THE TAF SITES AROUND/AFTER 02Z...COULD BE
STRONGER WITH THE POTENTIAL TO PRODUCE SOME SMALL HAIL UP TO 1 INCH
IN DIAMETER AS WELL AS GUSTY ERRATIC WINDS. THUNDERSTORMS SHOULD
END FOR BOTH KPUB AND KCOS AROUND 06Z WITH NORTH WINDS GUSTING TO 25
TO 30 KTS. BEST WINDOW FOR -TSRA AT KALS WILL BE FROM
01Z-04Z...WITH A ROUND OF GUSTY WINDS...AND LIGHTNING AND BRIEF
MODERATE RAINFALL THE MAIN THREATS. MTN AREAS WILL SEE WIDESPREAD MTN
OBSCURATIONS THROUGH THE EVENING WITH POTENTIAL FOR 2-6 INCHES OF
SNOW DURING THE OVERNIGHT HOURS ACROSS THE HIGHER PEAKS. GUSTY
NORTH TO NW WINDS WILL CONTINUE AT THE TAF SITES THROUGH
FRIDAY...WITH VFR CONDITIONS. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
44/10
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
NWS TOPEKA KS
644 PM CDT THU APR 26 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT TERM (TODAY THROUGH FRIDAY)...
19Z WATER VAPOR SHOWS A SHORTWAVE LIFTING EAST THROUGH AZ WITH A
LONG WAVE TROUGH OVER THE PACIFIC NORTHWEST. MID LEVEL RIDGING
REMAINS OVER THE CENTRAL PLAINS. AT THE SFC 19Z OBS SHOWED RIDGING
THROUGH MUCH OF KS WITH A FRONTAL BOUNDARY NEAR THE RED RIVER
VALLEY. A BAND OF LIGHT SHOWER ACTIVITY HAS SET UP WITHIN A NARROW
AXIS OF ISENTROPIC UPGLIDE ACROSS CENTRAL KS.
FOR THIS AFTERNOON AND THIS EVENING...THE RUC AND NAM SHOW THE
NARROW AXIS OF ISENTROPIC LIFT ON THE 310K SFC GRADUALLY LIFTING
NORTH AND EAST. BECAUSE OF THIS HAVE INCLUDED SOME SCATTERED SHOWERS
ACROSS NORTH CENTRAL KS WERE MID LEVEL MOISTURE IS A LITTLE BETTER.
THE NEXT SHIFT WILL NEED TO WATCH THE EASTWARD PROGRESSION. BUT
FOR NOT THINK SHOWERS WILL HAVE A HARD TIME MOVING EAST DUE TO A
LITTLE MORE DRY AIR IN THE MID LEVELS.
OVERNIGHT...THE SHORTWAVE OVER AZ WILL LIFT OUT OF THE SOUTHERN
ROCKIES AND MOVE INTO SOUTHERN NEB THROUGH THE DAY FRIDAY. THIS WAVE
IS EXPECTED TO PROVIDE THE FORCING TO SPARK CONVECTION LATE TONIGHT
AND THROUGH THE DAY FRIDAY. AT THIS POINT IT LOOKS LIKE THERE COULD
BE ELEVATED CONVECTION FORM DURING THE MORNING HOURS AND LIFT ACROSS
NORTHEAST KS. BOTH THE NAM AND GFS SHOW A NARROW WARM SECTOR
DESTABILIZING BY THE LATE MORNING OR EARLY AFTERNOON WITH SURFACE
BASED CAPES ON THE ORDER OF 1000 TO 1500 J/KG. WHILE A LITTLE ON THE
MARGINAL SIDE...DEEP LAYER SHEER OF 50 KTS WOULD BE SUFFICIENT FOR
STORMS IN THE WARM SECTOR TO BECOME SUPERCELLS. AT THIS POINT THE
MODELS PROG THE WARM FRONT TO SET UP JUST TO THE SOUTHWEST OF THE
FORECAST AREA WITH IT LIFTING NORTHEAST TOWARDS A CNK TO EMP LINE BY
FRIDAY EVENING. STORMS SOUTHWEST OF THIS LINE WILL HAVE THE GREATER
LIKELY HOOD OF BECOMING SEVERE. ALTHOUGH ELEVATED STORMS ACROSS
NORTHEAST KS COULD ALSO HAVE HAIL WITH THEM. THERE COULD BE AN
ISOLATED TORNADO THREAT ALONG THE WARM FRONT AS WELL IF A STORM WERE
TO DEVIATE TO THE SOUTHEAST AND RIDE ALONG THE BOUNDARY TAPPING INTO
THE GREATER HELICITY JUST NORTH OF THE BOUNDARY. WITH A CONVERGENCE
IN SOLUTIONS AMONG THE MODELS...HAVE INCREASED POPS INTO THE
CATEGORICAL RANGE ACROSS NORTHERN KS WHERE THE BEST FORCING IS
ANTICIPATED. HAVE LIKELY POPS ACROSS EAST CENTRAL KS THINKING THAT
COVERAGE OF STORMS MAY BE A LITTLE MORE BROKEN IN NATURE.
FRIDAY IS ALSO EXPECTED TO BECOME WINDY AS THE SFC LOW DEEPENS TO
THE WEST. THE INCREASING PRESSURE GRADIENT WILL LIKELY CAUSE EAST
AND SOUTHEAST WINDS TO GUST OVER 30 MPH. LOWS TONIGHT SHOULD NOT
DROP OFF AS MUCH GIVEN INCREASING CLOUD COVER AND A BETTER MIXED
BOUNDARY LAYER. THINK LOWS WILL BE IN THE MID 50S TO AROUND 60 FOR
MOST LOCATIONS. EXPECT A GOOD GRADIENT IN MAX TEMPS FOR TOMORROW
WITH CLOUDS AND EASTERLY WINDS KEEPING HIGHS IN THE LOW 60S OVER FAR
NORTHEAST KS. NEAR AND SOUTHWEST OF THE WARM FRONT...HIGHS SHOULD
WARM INTO THE MID 70S.
WOLTERS
MID TERM (FRIDAY EVENING THROUGH SUNDAY)...
BY FRIDAY EVENING MODELS AGREE ON A SIMILAR POSITION OF THE UPPER
TROUGH AND SURFACE LOW ACROSS CENTRAL INTO NORTHEAST KANSAS. SHOWERS
AND THUNDERSTORMS WILL REMAIN POSSIBLE EARLY FRIDAY EVENING BEFORE
THE SYSTEM QUICKLY EXITS NORTHEAST AND A DRIER AIR MASS FILLS IN ITS
PLACE WITH THE PASSAGE OF A COLD FRONT. BY SATURDAY MORNING THE
FRONTAL BOUNDARY WILL STALL NORTHEAST TO SOUTHWEST OVER SOUTHERN
KANSAS INTO CENTRAL OKLAHOMA. SURFACE RIDGE SETTLING OVER THE CWA
SHOULD KEEP MUCH OF THE AREA STABLE AND CAPPED THROUGHOUT THE
SATURDAY AFTERNOON PERIOD BEFORE ADDITIONAL SHOWERS AND A POSSIBLE
THUNDERSTORM OR TWO DEVELOPS ALONG AND NORTH OF THE BOUNDARY. WHILE
MUCH OF THE INSTABILITY REMAINS JUST SOUTH OF THE CWA...WOULD NOT BE
SURPRISED FOR AN ISOLATED THUNDERSTORM OR TWO. BEST CHANCE FOR
PRECIP ATTM APPEARS TO BE SUNDAY AFTERNOON INTO THE EVENING HOURS AS
ISENTROPIC LIFT INCREASES AND THE WARM FRONT LIFTS NORTHWARD. THE
COVERAGE AND SEVERITY OF ANY THUNDERSTORM STILL REMAINS UNCERTAIN AS
THE MODELS DEPICT VARYING SOLUTIONS ON THE PLACEMENT OF THE WARM
FRONT WITH RESPECT TO OUR AREA. HOWEVER...AMPLE MOISTURE ASSOCIATED
WITH THE BOUNDARY AND THE PRESENCE OF A SHORTWAVE TROUGH PASSING
THROUGH SUNDAY EVENING LEADS TO A DECENT CHANCE FOR ADDITIONAL
PRECIPITATION. TEMPERATURES STILL APPEAR TO BE ON TRACK FOR SATURDAY
AS CLEARER SKIES AND WEAK COLD AIR ADVECTION BEHIND THE SYSTEM SHOULD
HELP RAISE HIGHS INTO THE MIDDLE AND UPPER 60S TOWARDS EAST
CENTRAL KANSAS. CLOUD COVER ON SUNDAY WILL INHIBIT TEMPS TO ONLY
THE LOWER 60S.
EXTENDED TERM (SUNDAY EVENING THROUGH THURSDAY)...
VERY UNSETTLED PATTERN FOR THE EXTENDED TERM WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS EACH DAY. A STALLED SURFACE FRONT SUNDAY
EVENING INTO EARLY NEXT WEEK WILL PROVIDE THE SURFACE CONVERGENCE
ALONG WITH A SERIES OF SHORTWAVES EJECTING FROM THE MAIN TROUGH
OVER THE PACIFIC NORTHWEST INTO THE CENTRAL AND NORTHERN PLAINS.
MODELS ARE STILL HAVING DIFFICULTY WITH RESPECT TO THE TIMING OF
EACH SHORTWAVE TROUGH TO AFFECT THE CWA COMBINED LACK OF STRONG
FORCING FROM ANY FRONTAL BOUNDARIES. REGARDLESS...CONTINUOUS WARM
AIR ADVECTION AND DEWPOINTS RANGING FROM THE UPPER 50S TO MIDDLE
60S SUGGEST CONTINUING CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH THURSDAY. SOUNDING PROFILES SHOW 0-6KM BULK SHEAR VALUES
MARGINAL AROUND 35 KTS WITH MIXED LAYER MUCAPE BETWEEN 1100 AND
1500 J/KG SUGGEST ANY STORMS ABLE TO DEVELOP WILL BE ELEVATED AND
COULD BE STRONG. HEAVY RAIN MAY ALSO BE LIKELY AS BOTH THE GFS AND
ECMWF SHOW PWAT VALUES WELL OVER AN INCH FOR EACH PERIOD IN THE
FORECAST. MAIN CONCERN WILL BE IF THE MAIN FORCING ALOFT WILL
COINCIDE WITH ANY SURFACE FEATURES TO ALLOW THE STRONGER STORMS TO
FORM. BESIDES THE PRECIP POSSIBILITIES...NEAR NORMAL TEMPERATURES
ON MONDAY ARE EXPECTED TO GRADUALLY WARM INTO THE UPPER 70S BY
THURSDAY AS THE THERMAL RIDGE AXIS STRETCHES NORTHWARD OVER THE
CENTRAL PLAINS.
BOWEN
&&
.AVIATION...
LITTLE CHANGE FROM PREVIOUS FORECAST WITH MVFR CIGS AND POSSIBLE
PRECIPITATION AFTER 6Z...BUT MAINLY IN THE 12Z-18Z PERIOD. WINDS
WILL INCREASE DURING THIS PERIOD...AGAINST DIURNAL TRENDS AS THE
POTENT SYSTEM NEARS. CHANCES FOR ADDITIONAL CONVECTION EXIST LATE
IN THIS FORECAST BUT TOO LOW FOR INCLUSION AT THIS POINT.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
631 PM CDT THU APR 26 2012
...UPDATE TO AVIATION...
.SYNOPSIS...
ISSUED AT 142 PM CDT THU APR 26 2012
EARLY THIS AFTERNOON...THE WATER VAPOR SATELLITE LOOP SHOWED THE
CENTER OF A COMPACT AND INTENSE UPPER LOW OVER WESTERN ARIZONA. A
FEW LIGHTNING STRIKES WERE NOTED JUST AHEAD OF THE INTENSE MID LEVEL
POTENTIAL VORTICITY CENTER TIED TO THE LOW. SIGNIFICANT MID LEVEL
DRYING ON WV LOOP WAS BEGINNING TO ADVANCE EASTWARD TOWARD
WESTERN/CENTRAL NEW MEXICO. 12Z RAOB ANALYSIS REVEALED 140 TO 170
METER HEIGHT FALLS AT 500MB ACROSS FAR SOUTHERN CALIFORNIA WHEN THE
LOW WAS CENTERED NEAR SAN DIEGO EARLIER THIS MORNING. IN THE LOW
LEVELS...A SURFACE LOW WAS POSITIONED ALONG THE RED RIVER NEAR
WICHITA FALLS, TX. THERE WAS A POOL OF SIGNIFICANT MOISTURE AT THE
SURFACE IN THE EASTERLY FLOW NORTH OF THE SURFACE LOW OVER MUCH OF
CENTRAL/SOUTHERN OKLAHOMA WITH 70 DEGREE DEWPOINTS COMMON AS OF
MIDDAY. THE EASTERLY SURFACE WINDS WERE PULLING MID 60S DEWPOINTS AS
FAR NORTHWEST AS LEFORS, TX IN THE EASTERN TEXAS PANHANDLE. THE
EAST-SOUTHEAST WINDS CONTINUED TO ADVECT THIS MOISTURE NORTHWESTWARD
DEEPER INTO THE PANHANDLES.
&&
.SHORT TERM...(THIS EVENING THROUGH DAYBREAK FRIDAY)
ISSUED AT 250 PM CDT THU APR 26 2012
SEVERE WEATHER TONIGHT IS THE MAIN CHALLENGE IN TERMS OF A) TIMING,
B) CONVECTIVE MODE, C) MAIN HAZARDS. THE EVENT IS COMING INTO A BIT
BETTER FOCUS NOW THAT THE EXPECTED BEGINNING OF THE SEVERE WX EVENT
FOR SOUTHWEST KS IS 6-9 HOURS AWAY (AS OF 1930 UTC). SURFACE
DEWPOINTS WILL BE INCREASING NORTHWESTWARD THROUGH THE EVENING WITH
MOIST AXIS EXPECTED TO BE FROM WESTERN OKLAHOMA PANHANDLE INTO
EASTERN TEXAS PANHANDLE WITH 60F ISODROSOTHERM NOSING UP INTO THE
GUYMON, OK AREA BY 03Z. THIS YIELDS ABOUT 1800-2400 J/KG SBCAPE.
THE STRONGEST SURFACE FORCING AT THIS TIME WILL BE JUST WEST OF THE
INSTABILITY AXIS AND CONVECTION SHOULD BE ONGOING FROM SOUTHEAST
COLORADO DOWN INTO THE NORTHWESTERN TEXAS PANHANDLE. AT LEAST THIS
IS HOW THE LATEST RUC13 MODEL IS PLAYING THIS OUT IN THE CONVECTIVE
QPF FIELDS, WHICH MAKES PHYSICAL SENSE GIVEN WHERE THE FORCING IS AT
THAT TIME. THE THING THAT REALLY HAS US CONCERNED IS THE DEGREE OF
SHEAR IN THE 0-1KM AGL LAYER. IN ADVANCE OF THE SMALL SCALE UPPER
LOW...THE AGEOSTROPHIC RESPONSE IN THE LOW LEVELS WILL REALLY BE
MAXIMIZED FROM 03-09Z TONIGHT...AND THE 0-1KM AGL HELICITY WILL
EXCEED 300 M2/S2 OVER A LARGE AREA OF SOUTHWEST KANSAS. THE 0-1KM
ENERGY-HELICITY INDEX WILL REACH THE 4 TO 5 LEVEL, WHICH IS
EXTREMELY HIGH AND MORE THAN ENOUGH TO SUPPORT SIGNIFICANT LOW LEVEL
ROTATION IN THE STRONGEST STORMS...INCLUDING TORNADOES. CONVECTIVE
MODE IS THE REAL CHALLENGE. HOW LONG WILL THE SUPERCELL PHASE
LAST? THE EARLY STORMS COMING OUT OF SOUTHEAST COLORADO WILL MOST
LIKELY BE MORE SCATTERED WITH SOME DISTANCE STILL FROM THE STRONGEST
500-700MB COOLING AND MID LEVEL POTENTIAL VORTICITY (PV) ADVECTION.
WHEN THE "WALL OF FORCING" COMES OUT WITH THE INTENSE MID LEVEL COLD
ADVECTION AND PV ADVECTION...THE MODE WILL MOST LIKELY TRANSITION TO
A QUASI-LINEAR CONVECTIVE SYSTEM (QLCS). WILL HAVE TO REALLY WATCH
OUT FOR QLCS TORNADO EVENTS WHICH COULD BE SHORT-LIVED AND DIFFICULT
TO WARN FOR WITH MUCH LEAD TIME GIVEN THE CHARACTERISTICS OF THIS
TIME OF CONVECTIVE MODE AND THE ASSOCIATED LACK OF INTENSE MID LEVEL
MESOCYCLONES. ANOTHER QUESTION IS HOW FAR SOUTH THIS THREAT WILL
EXTEND INTO SOUTHWEST KANSAS. SEVERAL OF THE MODELS, MAINLY THE
LARGER-SCALE MODELS, INDICATE FAIRLY ROBUST CONVECTIVE QPF AS FAR
SOUTH AS THE OKLAHOMA BORDER BETWEEN 06-12Z. WILL PROBABLY EXTEND
LIKELY POPS DOWN CLOSE TO THE OKLAHOMA BORDER GIVEN THIS. THE
SEVERE WEATHER THREAT WILL CONTINUE ALL NIGHT AND THROUGH 12Z WITH
THE 09-12Z THREAT AREA SHIFTING NORTHEAST TOWARD THE
WAKEENEY-HAYS-LACROSSE AREAS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 353 PM CDT THU APR 26 2012
STORM CHANCES WILL PERSIST IN CENTRAL KANSAS AROUND HAYS THROUGH 20Z
SINCE THE UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE LOW WILL STILL
BE IN THIS AREA THROUGH EARLY AFTERNOON. AS DISCUSSED IN THE SHORT TERM
SECTION, THESE STORMS COULD BE SEVERE. IF STORMS PERSIST LONG ENOUGH
FOR DAYTIME HEATING TO LEAD TO HIGHER CAPE, THEN VERY LARGE HAIL
WOULD BE POSSIBLE AND POSSIBLY A TORNADO. SURFACE WINDS WILL BE
STRONG BEHIND THIS SYSTEM TOMORROW. A WIND ADVISORY WAS ISSUED FOR
MUCH OF SOUTHWEST KANSAS.
AFTER THIS SYSTEM PASSES, THE ASSOCIATED COLD FRONT WILL PASS
THROUGH KANSAS AND THEN STALL OUT ACROSS CENTRAL OKLAHOMA. THE
UPSTREAM SYSTEM THAT CAUSED THE AFOREMENTIONED SYSTEM TO EJECT ACROSS
THE PLAINS WILL HANG BACK OVER THE ROCKIES THROUGH SUNDAY AND
MONDAY. THE ASSOCIATED JET STREAK WILL BE SITUATED ACROSS THE
ROCKIES AND INTO KANSAS THROUGH THIS PERIOD. A WARM ADVECTION
PATTERN WILL DEVELOP AHEAD OF THIS TROUGH. THE GFS/GEM/UKMET
INDICATE QUITE A BIT OF PRECIPITATION ON THE COOL SIDE OF THE FRONT
IN SOUTHWEST KANSAS. HOWEVER, THE ECMWF SCENARIO OF DEVELOPING
WIDESPREAD THUNDERSTORMS ALONG THE FRONT OVER OKLAHOMA AND SOUTH
CENTRAL KANSAS COULD PREVENT SIGNIFICANT RAINFALL FURTHER NORTH.
HOWEVER, 20-40% THUNDERSTORM CHANCES WERE MAINTAINED FROM SATURDAY
NIGHT THROUGH MONDAY GIVEN THE UNCERTAINTY. CLOUDS AND POSSIBLE
PRECIPITATION CHANCES TO THE NORTH OF THE FRONT WILL PROBABLY KEEP
HIGH TEMPERATURES IN THE 60S TO LOWER 70S WITH LOWS IN THE 40S AND
50S.
BY TUESDAY AND WEDNESDAY, THE NEXT JET STREAK WILL BE MOVING ACROSS
THE ROCKIES AND APPROACHING THE CENTRAL HIGH PLAINS. FRONTOLYSIS
WILL OCCUR OVER OKLAHOMA, WITH ANOTHER FRONT DEVELOPING ACROSS THE
NORTHERN OR CENTRAL PLAINS. A DRYLINE AND SURFACE FRONT WILL
INTERSECT SOMEWHERE ACROSS THE CENTRAL HIGH PLAINS REGION.
THUNDERSTORMS CANNOT BE RULED OUT EITHER DAY AS 60F DEWPOINTS
WILL BE IN PLACE AHEAD OF THE DRYLINE. IT WILL BE WARMER BY THIS
TIME, WITH HIGHS IN THE UPPER 70S AND 80S AND LOWS IN THE 50S TO
LOWER 60S. THE HIGHEST MINIMUM TEMPERATURES, AS IS TYPICAL, WILL BE
IN SOUTH CENTRAL KANSAS WHERE DEWPOINTS WILL BE HIGHER.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 625 PM CDT THU APR 26 2012
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS DEVELOPING ACROSS
SOUTHEASTERN COLORADO INTO THE TEXAS PANHANDLE EARLY THIS EVENING
ARE EXPECTED TO SPREAD SLOWLY NORTHEAST INTO AND ACROSS SOUTHWESTERN
KANSAS OVERNIGHT. A FEW OF THESE STORMS COULD BECOME SEVERE
PRODUCING LARGE HAIL AND DAMAGING WINDS. A FEW TORNADOES WILL ALSO
BE POSSIBLE WITH THE STRONGEST STORMS ACROSS SOUTHWEST AND CENTRAL
KANSAS LATE TONIGHT THROUGH EARLY FRIDAY MORNING. OUTSIDE OF
IFR/MVFR CONDITIONS ASSOCIATED WITH ANY DEVELOPING STORMS, VFR
CONDITIONS ARE LIKELY TO PREVAIL AT ALL TAF SITES THROUGH EARLY
FRIDAY MORNING. AS FOR WINDS, A LEE SIDE TROUGH OF LOW PRESSURE WILL
CONTINUE TO STRENGTHEN ACROSS EXTREME EASTERN COLORADO TONIGHT. AS
A RESULT, STRONG SOUTHEASTERLY WINDS OF 20 TO 30KT WILL CONTINUE
THROUGH EARLY FRIDAY MORNING. A STRONG SURFACE LOW AND AN
ATTENDANT COLD FRONT IS THEN PROJECTED TO PUSH SLOWLY EASTWARD
ACROSS WESTERN KANSAS THROUGH THE DAY FRIDAY. THIS WILL RESULT IN
THE STRONG SOUTHEASTERLY WINDS BECOMING NORTHWESTERLY 25 TO 35KT
BEHIND THE FRONT THROUGH EARLY TO MID AFTERNOON FRIDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 61 78 45 69 / 80 70 0 0
GCK 56 77 43 68 / 80 40 0 0
EHA 53 77 43 68 / 70 10 0 0
LBL 56 79 45 69 / 70 20 0 0
HYS 61 74 43 67 / 70 80 0 0
P28 64 83 51 71 / 40 50 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ TO 8 PM CDT /7 PM MDT/
FRIDAY FOR KSZ043>045-061>065-075>080-086>088.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...JJOHNSON
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 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 WAKEFIELD VA
1006 PM EDT THU APR 26 2012
.SYNOPSIS...
A COLD FRONT CROSSES THE AREA TONIGHT...THEN STALLS ACROSS THE
CAROLINAS FRIDAY. HIGH PRESSURE BUILDS IN FROM THE NORTH FRIDAY.
THE FRONT MOVES BACK NORTH AS A WARM FRONT SATURDAY MORNING...
THEN STALLS ACROSS THE MID ATLANTIC REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
FINAL BATCH OF PRECIP ASSOCIATED WITH MCV PUSHING OFFSHORE AS OF
22Z. EXPECT DRY CONDS IN MOST AREAS FOR THE REMAINDER OF THE
NIGHT. STILL INCLUDED SLGT CHC FOR SH/TSTM THRU MIDNGT...BULK OF
UPSTREAM ACTIVITY OVER EXTREME W VA IS NOT EXPECTED TO MAKE IT
INTO THE WAKEFIELD CWA THOUGH LATEST HRRR AND RUC13 SHOW THE
POSSIBILITY OF SOME PRECIP THIS EVNG. OTW...EXPECT DECREASING
CLOUDINESS AS COLD FRNT PUSHES THRU THE AREA LATE OVRNGT. LOWS
U40S-M50S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
BOUNDARY PROGGED TO STALL ACROSS THE CAROLINAS SATURDAY AS HIGH
PRESSURE BUILDS SOUTH ACROSS THE AREA. EXPECT A DRY DAY WITH A
N-NW WIND BECOMING BREEZY AT TIMES (15-25 MPH). LOADED THE MIXED
LAYERED DEW POINTS INTO THE GRIDS WHICH RESULTS IN RH VALUES BTWN
20-30 PERCENT DURING PEAK HEATING HOURS. GIVEN TODAYS RAINFALL...
EXPECT THE FUEL MOISTURES TO STAY ELEVATED. HIGHS 60-65 EASTERN
SHORE AREAS TO ARND 70 ACROSS THE PIEDMONT.
FORECAST CONTINUES TO BE RATHER CHALLENGING FOR THE REST OF THE
WEEKEND GIVEN THE DIFFERENT SOLUTIONS TO WHERE THE FRONTAL BOUNDARY
ACTUALLY ENDS UP. CLOUDS INCREASE FRI NIGHT AS BOUNDARY BEGINS TO
APPROACH FROM THE SOUTH. SOME WEAK H85 ADVECTION NOTED ACROSS
WESTERN COUNTIES SO KEPT SLGHT CHC POPS THERE AFTER MIDNITE. LOWS
MAINLY IN THE 40S...HOWEVER EXPECT ENOUGH CLR SKIES ACROSS THE
EASTERN SHORE FOR TEMPS TO DROP INTO THE M-U30S IVOF SBY WITH
STEADY TEMPS AFTER THAT.
LATEST SUITE OF GUIDANCE SUPPORTS AT LEAST A CHC POPS ALL AREAS SAT
AS BOUNDARY PROGGED TO STALL ACROSS THE REGION. TEMPS TRICKY AS A
POTENTIAL IN-SITU WEDGE SCANARIO SETTING UP ACROSS THE PIEDMONT
WHERE TEMPS MAY BE HARD PRESSED TO GET MUCH ABOVE 60...RANGING TO
BTWN 65-70 SOUTH OF THE FRONT. KEPT CHC POPS SAT NIGHT TAPERING
OFF TO SLGHT CHC ACROSS SOUTHERN AREAS. LOWS IN THE 40S TO L50S.
LINGERING MOISTURE RESULTS IN A M CLDY DAY SUNDAY. STILL CAN NOT
RULE OUT A SHOWER (20 POPS IN THE GRIDS ATTM). HIGHS M-U60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE UPPER LEVEL LOW THAT WILL IMPACT THE WEATHER OVER THE WEEKEND
MOVES OFF TO THE NORTHEAST BY SUNDAY NIGHT AND MONDAY. UPPER LEVEL
RIDGING WILL TAKE OVER TOWARD MID WEEK.
THE COLD FRONTAL BOUNDARY WILL EXTEND THROUGH THE CAROLINAS AT THE
BEGINNING OF THE LONG TERM PERIOD. STRONG SURFACE HIGH NORTH OF THE
GREAT LAKES WILL RIDGE SOUTH THROUGH THE MID ATLANTIC STATES AND
PUSH THE COLD FRONT INTO NORTHERN GEORGIA. IN THE MEANTIME...LOW
PRESSURE WILL DEVELOP OVER THE MISSISSIPPI VALLEY AND HEAD E/NE
THROUGH THE OHIO VALLEY TO NORTHERN PORTIONS OF THE MID ATLANTIC
STATES. THIS WILL BRING THE FRONT BACK TO THE NORTH OF OUR AREA...
INCREASING BOTH TEMPERATURE AND MOISTURE. UNCERTAINTY WITH THE
TIMING OF ANY PCPN EXISTS FOR TUESDAY THROUGH THURSDAY. INTRODUCED
CHC (30 PERCENT) SHOWERS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
UPPER LEVEL RIDGING MAY LIMIT PCPN POTENTIAL.
HIGH TEMPERATURES IN THE 60S MONDAY WARM TO THE MID TO UPPER 70S
(COOLER NEAR THE COAST) WEDNESDAY AND THURSDAY. LOWS AROUND 40 TO
THE MID 40S MONDAY MORNING WARM TO THE MID TO UPPER 50S WEDNESDAY
AND THURSDAY MORNINGS.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
A COLD FRONT WILL CROSS THE AREA TONIGHT AND THIS WILL CLEAR THE
CLOUDS OUT OF THE AREA WITH VFR CONDITIONS FOR FRIDAY INTO FRIDAY
NIGHT. SHORT RANGE MODELS SHOW THAT SOME OF THE THUNDERSTORM
ACTIVITY TO THE WEST OF THE MOUNTAINS MAY IMPACT THE AREA AROUND
06Z. HAVE DECIDED TO LEAVE -TSRA OUT OF TAFS DUE TO UNCERTAINTY.
FLYING CONDITIONS COULD DETERIORATE DURING ANY SHRA/-TSRA. GOOD
MIXING COUPLED WITH STRONGER WINDS ALOFT WILL CREATE BREEZY
CONDITIONS ON FRIDAY...AS N/NW WINDS MAY GUST OVER 20 KT.
FOR THE WEEKEND A FRONTAL BOUNDARY WILL BE NEARLY STATIONARY CLOSE
TO THE AREA WITH LOWS MOVING ALONG IT PROVIDING MVFR TO IFR
CONDITIONS.
&&
.MARINE...
WINDS AND SEAS FOR THE MAJORITY OF THE MARINE AREA WILL REMAIN
BELOW SCA CRITERIA UNTIL A COLD FRONTAL PASSAGE SHORTLY AFTER
MIDNIGHT. SW WINDS ALONG A LONG ENOUGH FETCH HAVE CREATED 5 FT
SEAS IN THE NORTHERN COASTAL WATERS...THUS HAVE STARTED THE SCA
FROM FENWICK ISLAND TO PARRAMORE ISLAND FOR SEAS AT 02Z. N/NW WINDS
INCREASE QUICKLY FROM NORTH TO SOUTH ACROSS THE WATERS AS A COLD
SWEEPS THROUGH. A SCA IS IN EFFECT FOR ALL THE WATERS FROM 05 TO
18Z. SOME FINE TUNING FOR ENDING TIMES MAY BE NEEDED DURING FUTURE
SHIFTS.
A BROAD NORTHERLY FETCH IN THE OFFSHORE WATERS MAY PRODUCE 5 FT
SEAS IN THE OUTER PORTIONS OF THE COASTAL ZONES ON SUNDAY.
OTHERWISE NO MARINE ISSUES ARE CURRENTLY FORECAST BEYOND THE NW
SURGE THAT OCCURS OVERNIGHT AND FRIDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 PM EDT FRIDAY FOR ANZ630>638-654-
656-658.
SMALL CRAFT ADVISORY UNTIL 2 PM EDT FRIDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR/MAS
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...JAB/DAP
MARINE...DAP/LSA
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
813 PM EDT THU APR 26 2012
.SYNOPSIS...
A COLD FRONT CROSSES THE AREA TONIGHT...THEN STALLS ACROSS THE
CAROLINAS FRIDAY. HIGH PRESSURE BUILDS IN FROM THE NORTH FRIDAY.
THE FRONT MOVES BACK NORTH AS A WARM FRONT SATURDAY MORNING...
THEN STALLS ACROSS THE MID ATLANTIC REGION THROUGH THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
FINAL BATCH OF PRECIP ASSOCIATED WITH MCV PUSHING OFFSHORE AS OF
22Z. EXPECT DRY CONDS IN MOST AREAS FOR THE REMAINDER OF THE
NIGHT. STILL INCLUDED SLGT CHC FOR SH/TSTM THRU MIDNGT...BULK OF
UPSTREAM ACTIVITY OVER EXTREME W VA IS NOT EXPECTED TO MAKE IT
INTO THE WAKEFIELD CWA THOUGH LATEST HRRR AND RUC13 SHOW THE
POSSIBILITY OF SOME PRECIP THIS EVNG. OTW...EXPECT DECREASING
CLOUDINESS AS COLD FRNT PUSHES THRU THE AREA LATE OVRNGT. LOWS
U40S-M50S.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
BOUNDARY PROGGED TO STALL ACROSS THE CAROLINAS SATURDAY AS HIGH
PRESSURE BUILDS SOUTH ACROSS THE AREA. EXPECT A DRY DAY WITH A
N-NW WIND BECOMING BREEZY AT TIMES (15-25 MPH). LOADED THE MIXED
LAYERED DEW POINTS INTO THE GRIDS WHICH RESULTS IN RH VALUES BTWN
20-30 PERCENT DURING PEAK HEATING HOURS. GIVEN TODAYS RAINFALL...
EXPECT THE FUEL MOISTURES TO STAY ELEVATED. HIGHS 60-65 EASTERN
SHORE AREAS TO ARND 70 ACROSS THE PIEDMONT.
FORECAST CONTINUES TO BE RATHER CHALLENGING FOR THE REST OF THE
WEEKEND GIVEN THE DIFFERENT SOLUTIONS TO WHERE THE FRONTAL BOUNDARY
ACTUALLY ENDS UP. CLOUDS INCREASE FRI NIGHT AS BOUNDARY BEGINS TO
APPROACH FROM THE SOUTH. SOME WEAK H85 ADVECTION NOTED ACROSS
WESTERN COUNTIES SO KEPT SLGHT CHC POPS THERE AFTER MIDNITE. LOWS
MAINLY IN THE 40S...HOWEVER EXPECT ENOUGH CLR SKIES ACROSS THE
EASTERN SHORE FOR TEMPS TO DROP INTO THE M-U30S IVOF SBY WITH
STEADY TEMPS AFTER THAT.
LATEST SUITE OF GUIDANCE SUPPORTS AT LEAST A CHC POPS ALL AREAS SAT
AS BOUNDARY PROGGED TO STALL ACROSS THE REGION. TEMPS TRICKY AS A
POTENTIAL IN-SITU WEDGE SCANARIO SETTING UP ACROSS THE PIEDMONT
WHERE TEMPS MAY BE HARD PRESSED TO GET MUCH ABOVE 60...RANGING TO
BTWN 65-70 SOUTH OF THE FRONT. KEPT CHC POPS SAT NIGHT TAPERING
OFF TO SLGHT CHC ACROSS SOUTHERN AREAS. LOWS IN THE 40S TO L50S.
LINGERING MOISTURE RESULTS IN A M CLDY DAY SUNDAY. STILL CAN NOT
RULE OUT A SHOWER (20 POPS IN THE GRIDS ATTM). HIGHS M-U60S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
THE UPPER LEVEL LOW THAT WILL IMPACT THE WEATHER OVER THE WEEKEND
MOVES OFF TO THE NORTHEAST BY SUNDAY NIGHT AND MONDAY. UPPER LEVEL
RIDGING WILL TAKE OVER TOWARD MID WEEK.
THE COLD FRONTAL BOUNDARY WILL EXTEND THROUGH THE CAROLINAS AT THE
BEGINNING OF THE LONG TERM PERIOD. STRONG SURFACE HIGH NORTH OF THE
GREAT LAKES WILL RIDGE SOUTH THROUGH THE MID ATLANTIC STATES AND
PUSH THE COLD FRONT INTO NORTHERN GEORGIA. IN THE MEANTIME...LOW
PRESSURE WILL DEVELOP OVER THE MISSISSIPPI VALLEY AND HEAD E/NE
THROUGH THE OHIO VALLEY TO NORTHERN PORTIONS OF THE MID ATLANTIC
STATES. THIS WILL BRING THE FRONT BACK TO THE NORTH OF OUR AREA...
INCREASING BOTH TEMPERATURE AND MOISTURE. UNCERTAINTY WITH THE
TIMING OF ANY PCPN EXISTS FOR TUESDAY THROUGH THURSDAY. INTRODUCED
CHC (30 PERCENT) SHOWERS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.
UPPER LEVEL RIDGING MAY LIMIT PCPN POTENTIAL.
HIGH TEMPERATURES IN THE 60S MONDAY WARM TO THE MID TO UPPER 70S
(COOLER NEAR THE COAST) WEDNESDAY AND THURSDAY. LOWS AROUND 40 TO
THE MID 40S MONDAY MORNING WARM TO THE MID TO UPPER 50S WEDNESDAY
AND THURSDAY MORNINGS.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
A COLD FRONT WILL CROSS THE AREA TONIGHT AND THIS WILL CLEAR THE
CLOUDS OUT OF THE AREA WITH VFR CONDITIONS FOR FRIDAY INTO FRIDAY
NIGHT. SHORT RANGE MODELS SHOW THAT SOME OF THE THUNDERSTORM
ACTIVITY TO THE WEST OF THE MOUNTAINS MAY IMPACT THE AREA AROUND
06Z. HAVE DECIDED TO LEAVE -TSRA OUT OF TAFS DUE TO UNCERTAINTY.
FLYING CONDITIONS COULD DETERIORATE DURING ANY SHRA/-TSRA. GOOD
MIXING COUPLED WITH STRONGER WINDS ALOFT WILL CREATE BREEZY
CONDITIONS ON FRIDAY...AS N/NW WINDS MAY GUST OVER 20 KT.
FOR THE WEEKEND A FRONTAL BOUNDARY WILL BE NEARLY STATIONARY CLOSE
TO THE AREA WITH LOWS MOVING ALONG IT PROVIDING MVFR TO IFR
CONDITIONS.
&&
.MARINE...
WINDS AND SEAS WILL REMAIN BELOW SCA CRITERIA UNTIL A COLD FRONTAL
PASSAGE SHORTLY AFTER MIDNIGHT. N/NW WINDS INCREASE QUICKLY FROM
NORTH TO SOUTH ACROSS THE WATERS AS A COLD SWEEPS THROUGH. A SCA IS
IN EFFECT FOR ALL THE WATERS FROM 05 TO 18Z. SOME FINE TUNING FOR
ENDING TIMES MAY BE NEEDED DURING FUTURE SHIFTS.
A BROAD NORTHERLY FETCH IN THE OFFSHORE WATERS MAY PRODUCE 5 FT
SEAS IN THE OUTER PORTIONS OF THE COASTAL ZONES ON SUNDAY.
OTHERWISE NO MARINE ISSUES ARE CURRENTLY FORECAST BEYOND THE NW
SURGE THAT OCCURS OVERNIGHT AND FRIDAY.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 2 PM EDT FRIDAY FOR
ANZ630>638-650-652-654-656-658.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR/MAS
SHORT TERM...MPR
LONG TERM...LSA
AVIATION...JAB/DAP
MARINE...LSA
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 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
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 GREAT FALLS MT
914 PM MDT THU APR 26 2012
.UPDATE...
EXTREME SHORT RANGE MODELS INCLUDING THE HRRR AND RUC HAVE MOVED
INTO TIGHT AGREEMENT WITH LATEST NAM AND GFS RUNS SHOWING A
SIGNIFICANTLY HIGHER AMOUNT OF MOISTURE OVER THE MOUNTAINS OF
SOUTHWEST MONTANA TONIGHT. DUE TO THE SIGNIFICANTLY SHORT
TIME FRAME HAVE MADE THE NONTRADITIONAL DECISION TO UPGRADE THE
WINTER STORM WATCH TO A WARNING THIS EVENING WITH THIS NEW DATA.
DUE TO THE INCREASED CONFIDENCE FOR THE POTENTIAL OF SIGNIFICANT
IMPACTS BEFORE THE NEXT STANDARD FORECAST SUITE UPDATE. THE
WARNING IS IN EFFECT FOR ELEVATIONS ABOVE 6500 FEET...WITH NO
ADVISORY BELOW 6500 FEET DUE TO THE WARMER TEMPERATURES EXPECTED
IN THE VALLEY LOCATIONS OF THE SOUTHWEST TONIGHT. THESE ARE THE
EXPECTED CONDITIONS AT THIS TIME...HOWEVER THERE IS A SLIGHT
POSSIBILITY THAT SNOW ACCUMULATIONS COULD MAKE IT DOWN INTO THE
LOWER ELEVATIONS AND ADDITIONAL HIGHLIGHTS MAY BECOME NECESSARY.
WITH THIS UPDATE...THE IMPACTS FOR LOCATIONS OUTSIDE OF SOUTHWEST
MONTANA LOOK LESS IMPRESSIVE AND DECIDED TO DELAY THE WINTER
WEATHER WATCH UNTIL 1800Z FRIDAY. SUK
&&
.AVIATION...
UPDATED 2355Z.
A TROUGH OF LOW PRESSURE AND COLD FRONT WILL BRING ACTIVE WEATHER TO
THE AREA THROUGH THE TAF PERIOD. AN UNSTABLE AIRMASS OVER THE REGION
WILL RESULT IN SCATTERED SHOWERS AND THUNDERSTORMS...SOME WITH GUSTY
WINDS...THROUGH THE EARLY EVENING HOURS. A COLD FRONT WILL BRING A
LINE OF SHOWERS AND THUNDERSTORMS AND WIND SHIFT THROUGH THE AREA
FROM WEST TO EAST...AFFECTING KHLN...KCTB...AND KGTF AFTER 01Z AND
KBZN... KLWT...AND KHVR CLOSER TO 06Z. WESTERLY WINDS WILL INCREASE
ACROSS THE AREA OVERNIGHT AND INTO FRIDAY ALONG WITH AREAS OF
PRECIPITATION AND LOWER CEILINGS...RESULTING IN MVFR CONDITIONS AND
MOUNTAIN OBSCURATION. LANGLIEB
&&
.PREV DISCUSSION...
/ISSUED 555 PM MDT THU APR 26 2012/
TODAY THROUGH SATURDAY EVENING...FORECAST STILL ON TRACK FOR PAIR OF
VERY MOIST PACIFIC WEATHER SYSTEMS TO BRING WIDESPREAD AND LONG
DURATION PRECIPITATION ALONG WITH MUCH COOLER TEMPERATURES OVER OUR
REGION THROUGH THE ENTIRE SHORT-TERM FORECAST AREA. CURRENT
SATELLITE IMAGERY SHOWS THE SLIGHTLY WEAKER SYSTEM NOW IN ARIZONA
AND BEGINNING TO LIFT NORTHEASTWARD. MEANWHILE...THE MUCH DEEPER
UPPER LEVEL TROF IS CLOSING IN ON THE WA/OR COAST AND IS EXPECTED TO
MOVE INLAND TONIGHT. ASSOCIATED MOISTURE PLUME WITH THESE SYSTEM
COVERS A BROAD AREA OF THE GREAT BASIN AND NRN ROCKIES WITH
ADDITIONAL MOISTURE EXPECTED TO ACCOMPANY THE STRONGER TROF. AS OF
230 PM LEADING EDGE OF THE MOISTURE IS LOCATED IN OVER OUR FORECAST
AREA WHERE IT HAS BEGUN TO MIX WITH LIFT AND INSTABILITY TO GENERATE
ISOLATED SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST AND CENTRAL
MT. EXPECT THIS ACTIVITY TO BROADEN IN COVERAGE THIS AFTN/EVE BUT
INSTABILITY WILL WEAKEN AFTER SUNSET SO SHOWERS WILL CONTINUE BUT
THUNDERSTORMS SHOULD DISSIPATE. BEST NEWS IN THE OUTLOOK IS THAT
PRIMARY SHORT-TERM FORECAST MODELS ARE IN MUCH BETTER AGREEMENT ON
CONDITIONS FOR TOMORROW AND SATURDAY...CERTAINLY BETTER THAN THE
GLARING DIFFERENCES SEEN THE PAST FEW DAYS. THE TWO WEATHER SYSTEMS
WILL CONTINUE TO TRACK TOWARD EACH OTHER AND EVENTUALLY MERGE OVER
NORTHERN WYOMING LATE FRI...THEN GRADUALLY LIFT INTO FAR SOUTHEAST
MT ON SAT. AS IT DOES SO...ADDITIONAL MOISTURE WILL BE PULLED FROM
THE DAKOTAS OVER THE NRN FLANK OF THE CLOSED LOW PRESSURE
AREA...KEEPING A NEAR CONTINUOUS PERIOD OF RAIN...RAIN/SNOW
MIX...AND SNOW GOING THROUGH SATURDAY. MODELS STILL SHOW SOME
SLIGHT VARIATIONS IN TOTAL PRECIPITATION AND AMOUNTS BUT
GENERALLY EXPECT ONE-HALF TO THREE-QUARTERS OF AN INCH OVER MUCH OF
THE REGION. SNOW WILL DEVELOP OVER THE SOUTHWEST MTNS TONIGHT AND
GRADUALLY SPREAD INTO THE HIGHER ELEVATIONS OF CENTRAL MT FRI PM-SAT
AM. SNOW LEVELS WILL GRADUALLY DROP THROUGH SATURDAY SO A FEW
INCHES OF WET SLUSH ARE POSSIBLE AT ELEVATIONS AROUND 3000 FT WITH
SIGNIFICANTLY HIGHER SNOW AMOUNTS FOR THE CENTRAL MTN RANGES. THUS
CURRENT WINTER WEATHER WATCH FOR ALL BUT OUR NORTHEAST ZONES REMAINS
IN EFFECT AND BEGINS AT MIDNIGHT TONIGHT.
GIVEN THE EXPECTED PRECIP AMOUNTS...RIVERS AND STREAMS WILL CONTINUE
TO RISE. A FEW CREEKS IN GLACIER COUNTY ARE ALREADY NEAR
BANKFULL...SO HAVE ISSUED A SMALL STREAM FLOOD ADVISORY THERE.
FURTHER DETAILS ARE IN THE HYDROLOGY SECTION BELOW.
WARANAUSKAS
SATURDAY NIGHT THROUGH THURSDAY...MODERATE AGREEMENT IN MODEL
GUIDANCE REGARDING THE TIMING AND LOCATION OF THE UPPER LEVEL LOW AS
IT MOVES OUT OF THE REGION. CURRENT FORECAST FAVORS THE GFS SOLUTION
AND KEEPS RESIDUAL MOISTURE AROUND AS THE GFS IS SLOWER TO PUSH THE
SYSTEM NORTHEASTWARD. PRECIPITATION SHOULD BE LIGHT AND REMAIN AS
RAIN...POSSIBLY A RAIN SNOW MIX...IN THE LOWER ELEVATIONS WITH SNOW
IN THE MOUNTAINS. A MORE ZONAL FLOW DEVELOPS EARLY NEXT WEEK AND
WILL PERSIST THROUGH WEDNESDAY. A SHORTWAVE WILL MOVE OVER THE AREA
MONDAY EVENING BRINGING A CHANCE OF PACIFIC MOISTURE...MAINLY TO THE
ROCKY MOUNTAIN FRONT AND SW MONTANA...AND THEN AGAIN ON TUESDAY
EVENING AFFECTING THE SAME AREAS. BY WEDNESDAY AFTERNOON EXPECT
CLEARING AND THE FLOW TO BECOME MORE SOUTHWESTERLY. TEMPERATURES
WILL START OFF A LITTLE COOL ON SUNDAY AND APPROACH SEASONAL
AVERAGES THE REMAINDER OF THE PERIOD. MERCER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 39 50 33 47 / 80 60 70 70
CTB 34 48 31 49 / 90 60 70 70
HLN 36 48 32 49 / 90 50 60 60
BZN 31 46 23 46 / 90 80 60 60
WEY 27 35 18 37 / 100 80 70 60
DLN 30 43 24 46 / 100 70 50 50
HVR 38 51 33 45 / 80 70 80 60
LWT 35 47 30 41 / 90 70 70 70
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY
AFTERNOON BROADWATER...CASCADE...CENTRAL AND SOUTHERN LEWIS AND
CLARK...CHOUTEAU...EASTERN GLACIER...EASTERN PONDERA...EASTERN
TETON...FERGUS...JEFFERSON...JUDITH BASIN...MEAGHER...NORTHERN
ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT.
WINTER STORM WARNING UNTIL NOON MDT FRIDAY FOR ELEVATIONS ABOVE
6500 FEET FOR BEAVERHEAD...GALLATIN...MADISON.
SMALL STREAM FLOOD ADVISORY FOR GLACIER COUNTY UNTIL NOON SATURDAY.
&&
$$
SHORT TERM...SUK
LONG TERM...MERCER
AVIATION...LANGLIEB
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
915 PM CDT THU APR 26 2012
.DISCUSSION...
FIRST BAND OF LIGHT SHOWERS OR SPRINKLES IS MOVING INTO WESTERN
PORTIONS OF THE FORECAST AREA. RAIN IS REACHING THE GROUND IN
NORTHEAST NEBRASKA WHERE DBZ RETURNS HAVE BEEN SLIGHTLY HEAVIER.
STILL SOME DRY AIR AT THE SURFACE WHICH HAS TO BE OVERCOME FIRST.
FURTHER SOUTH OF COLUMBUS TOWARD BEATRICE...PROBABLY NOTHING MORE
THAN A FEW SPRINKLES THERE. THIS BAND WILL CONTINUE TO PUSH
EASTWARD THIS EVENING...AND COULD LIKELY STILL SEE SOME SPRINKLES
MOVE TOWARD THE REMAINDER OF EASTERN NEBRASKA TOWARD THE MISSOURI
RIVER.
BELIEVE THERE WILL PROBABLY BE A BREAK IN THE PRECIPITATION BEHIND
THIS INITIAL BAND. REGIONAL RADAR MOSAIC SHOWS A LOT OF PRECIP
FREE AREAS ACROSS CENTRAL KANSAS AND CENTRAL KANSAS...WHICH BOTH
THE 21Z SREF AND 00Z NAM PICKED UP ON. ADJUSTED POPS OVERNIGHT TO
ACCOUNT FOR THAT...ALTHOUGH STILL LEFT IN A SLIGHT CHANCE FOR
MAINLY A SPRINKLE. THE MAIN AREA OF STEADIER RAIN/SHOWERS DOES
SPREAD ACROSS THE FORECAST AREA FRIDAY MORNING...BUT PERHAPS JUST
A COUPLE HOURS SLOWER THAN PREVIOUSLY THOUGHT.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 656 PM CDT THU APR 26 2012/
AVIATION...00Z TAFS FOR KOMA...KLNK AND KOFK. RAIN WILL
EVENTUALLY DEVELOP AT ALL TAF SIGHTS...INITIALLY AT KOFK BY AS
SOON AS 06Z...AND LATER AT KLNK AND KOMA. BELIEVE THE SPRINKLES
ACROSS SOUTHEAST NEBRASKA CURRENTLY WILL NOT MAKE IT AS FAR EAST
AS LINCOLN THIS EVENING. VFR CONDITIONS BECOME MVFR ONCE THE RAIN
MOVES IN. ALSO BELIEVE THAT EAST SOUTHEAST WINDS WILL CONTINUE TO
STRENGTHEN THROUGH THE PERIOD...EVENTUALLY BECOMING QUITE BREEZY
WITH SUSTAINED WINDS OF 18 TO 22 MPH WITH HIGHER GUSTS. THERE ALSO
COULD BE SOME LOW LEVEL WIND SHEAR FROM ABOUT 09Z-15Z AS WELL.
PREV DISCUSSION... /ISSUED 348 PM CDT THU APR 26 2012/
SHORT TERM...TONIGHT.
THE MAIN FORECAST CONCERN TONIGHT WILL BE THE CHANCE FOR SHOWERS.
THE CLOUDS WILL CONTINUE TO THICKEN THIS EVENING AS THE FIRST
AREA OF LIFT MOVES ACROSS THE FORECAST AREA. THE SHORT TERM MODELS
DO NOT HAVE A REAL GOOD HANDLE ON THE PRECIP FROM WESTERN NEBRASKA
INTO KANSAS...ALTHOUGH MOST OF THIS IS LIGHT. THE GFS WAS DOING
THE BEST AND THE 15Z SREF BETTER THAN THE 09Z SREF. THE HRRR HAS
SOME PRECIP UP TO THE CWA...THEN DISSIPATES IT THIS EVENING WITH
SOME INCREASE IN THE NORTHEAST PART OF THE FORECAST AREA AFTER
06Z.DUE TO THE DRY AIR IN PLACE...THERE MAY BE A FEW SHOWERS OR
SPRINKLES...WITH THE BEST CHANCE FOR SOME MINOR PRECIP
ACCUMULATIONS IN THE WEST OF WAYNE AND LINCOLN AND SPRINKLES
FARTHER EAST. DID NOT MENTION THUNDER AS BOTH THE NAM/GFS TENDED
TO KEEP THE BETTER INSTABILITY IN THE WESTERN PART OF THE CWA OR
TO THE WEST TONIGHT. SOUTHEAST WINDS LOOK TO INCREASE INTO THE 15
TO 30 MPH RANGE OVERNIGHT.
ZAPOTOCNY
LONG TERM...SATURDAY THROUGH THURSDAY.
PRECIPITATION CHANCES WILL PROVIDE THE MAIN FORECAST CHALLENGES
THROUGH THE EARLY PART OF THIS PERIOD.
500 MB CHART FROM THIS MORNING SHOWED A STRONG AND COMPACT CLOSED
LOW JUST WEST OF SAN DIEGO. THIS FEATURE HAD 12 HOUR HEIGHT FALLS
OF AROUND 170 METERS. IT WILL CONTINUE TO TRACK QUICKLY NORTHEAST
AND SHOULD BE OVER THE EASTERN COLORADO/NORTHWEST KANSAS BORDER
AREA BY 12Z FRIDAY. AS THIS FEATURE LIFTS OUT INTO THE CENTRAL
PLAINS FRIDAY...EXPECT FAIRLY WIDESPREAD PRECIPITATION TO OCCUR.
LOW LEVELS WILL BE SLOW TO SATURATE...WITH MAIN 850 MB MOISTURE
AND INSTABILITY AXIS GENERALLY REMAINING WEST AND SOUTH OF THE
FORECAST AREA. 12Z GFS SHOWED 850 DEWPOINTS REACHING 10-12
DEGREES CELCIUS IN PARTS OF SOUTHEAST NEBRASKA DURING THE DAY.
CAN NOT RULE OUT A FEW STORMS INTO THAT AREA...BUT MAIN SEVERE
THREAT SHOULD STAY TO OUR SOUTH FRIDAY. TEMPERATURES WILL BE COOL
WITH EASTERLY WINDS...CLOUDS AND PRECIPITATION. GENERALLY STAYED
BELOW MOS GUIDANCE FOR HIGHS FRIDAY.
KEPT FAIRLY HIGH RAIN CHANCES FRIDAY NIGHT AND SOME THUNDERSTORMS
STILL SEEM POSSIBLE IN THE EVENING...ESPECIALLY OVER SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA. FAIRLY STRONG DRYING TAKES PLACE
BEHIND THE MAIN SHORTWAVE TROUGH BY LATE FRIDAY NIGHT SO EXPECT
SATURDAY TO BE MOSTLY DRY. THE 12Z ECMWF AND 12Z GFS MODEL SOLUTIONS
START TO DIVERGE BY SATURDAY NIGHT INTO SUNDAY. GFS IS MORE
AGGRESSIVE WITH PRECIPITATION SPREADING BACK INTO THE AREA FROM
THE SOUTH. GENERALLY FELT THE ECMWF WAS HANDLING THE PATTERN
BETTER THAN THE GFS...BUT COULD NOT RULE OUT GFS SOLUTION SO
BLENDED SOME OF THAT THINKING INTO GRIDS. A DIFFERENT CLOSED
LOW...ASSOCIATED WITH THE TROUGH CURRENTLY OFF THE PACIFIC
NORTHWEST...WILL MOVE INTO NORTHERN WYOMING OR SOUTHERN MONTANA BY
00Z SATURDAY. THIS SHOULD TRACK EAST TOWARD THE WESTERN DAKOTAS
THROUGH SATURDAY EVENING AND THEN LIFT NORTH THROUGH SUNDAY NIGHT.
MAIN AFFECTS FROM THAT SHOULD STAY TO OUR WEST OR SOUTH.
A WEAK TROUGH REMAINS OVER THE ROCKIES THROUGH MID WEEK...WITH
SEVERAL RIPPLES IN THE FLOW MOVING OUT ACROSS OUR AREA. THE TIMING
DIFFERENCES PERSIST THROUGH DAY 7.
MILLER
AVIATION...
18Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE FORECAST THROUGH 27/15Z. FIRST PIECE OF ENERGY
WILL LIFT ACROSS THE TAF SITES THIS AFTERNOON. MID LEVEL CLOUDS
WILL BE ON THE INCREASE MOSTLY AT FL100...BUT ALSO SOME SCT-BKN AT
FL050. DRY AIR SHOULD LIMIT WIDESPREAD PRECIPITATION. THERE MAY BE
A FEW SPRINKLES OR SHOWERS...HOWEVER DUE TO SPOTTY NATURE HAVE NOT
INCLUDED. THE STRONGER PIECE OF ENERGY WILL MOVE ACROSS THE AREA
FRIDAY. DEEP MOISTURE WILL BE AVAILABLE WITH STRONGER LIFT AND
MORE WIDESPREAD PRECIPITATION ALONG WITH LOWER MVFR CIGS POSSIBLE.
NORTHEAST WINDS WILL BECOME EAST AT 10 TO 15KTS WITH SOME GUSTS 20
TO 25KTS. TONIGHT AFTER 06Z...EAST TO SOUTHEAST WINDS WILL
INCREASE TO 15 TO 25KTS WITH GUSTS 25 TO 30KTS. MENTIONED LOW
LEVEL WIND SHEAR AT KOMA AND KLNK AFT 09Z WITH 2K WINDS INCREASING
TO 45 TO 55KTS.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
656 PM CDT THU APR 26 2012
.AVIATION...00Z TAFS FOR KOMA...KLNK AND KOFK. RAIN WILL
EVENTUALLY DEVELOP AT ALL TAF SIGHTS...INITIALLY AT KOFK BY AS
SOON AS 06Z...AND LATER AT KLNK AND KOMA. BELIEVE THE SPRINKLES
ACROSS SOUTHEAST NEBRASKA CURRENTLY WILL NOT MAKE IT AS FAR EAST
AS LINCOLN THIS EVENING. VFR CONDITIONS BECOME MVFR ONCE THE RAIN
MOVES IN. ALSO BELIEVE THAT EAST SOUTHEAST WINDS WILL CONTINUE TO
STRENGTHEN THROUGH THE PERIOD...EVENTUALLY BECOMING QUITE BREEZY
WITH SUSTAINED WINDS OF 18 TO 22 MPH WITH HIGHER GUSTS. THERE ALSO
COULD BE SOME LOW LEVEL WIND SHEAR FROM ABOUT 09Z-15Z AS WELL.
&&
.PREV DISCUSSION... /ISSUED 348 PM CDT THU APR 26 2012/
SHORT TERM...TONIGHT.
THE MAIN FORECAST CONCERN TONIGHT WILL BE THE CHANCE FOR SHOWERS.
THE CLOUDS WILL CONTINUE TO THICKEN THIS EVENING AS THE FIRST
AREA OF LIFT MOVES ACROSS THE FORECAST AREA. THE SHORT TERM MODELS
DO NOT HAVE A REAL GOOD HANDLE ON THE PRECIP FROM WESTERN NEBRASKA
INTO KANSAS...ALTHOUGH MOST OF THIS IS LIGHT. THE GFS WAS DOING
THE BEST AND THE 15Z SREF BETTER THAN THE 09Z SREF. THE HRRR HAS
SOME PRECIP UP TO THE CWA...THEN DISSIPATES IT THIS EVENING WITH
SOME INCREASE IN THE NORTHEAST PART OF THE FORECAST AREA AFTER
06Z.DUE TO THE DRY AIR IN PLACE...THERE MAY BE A FEW SHOWERS OR
SPRINKLES...WITH THE BEST CHANCE FOR SOME MINOR PRECIP
ACCUMULATIONS IN THE WEST OF WAYNE AND LINCOLN AND SPRINKLES
FARTHER EAST. DID NOT MENTION THUNDER AS BOTH THE NAM/GFS TENDED
TO KEEP THE BETTER INSTABILITY IN THE WESTERN PART OF THE CWA OR
TO THE WEST TONIGHT. SOUTHEAST WINDS LOOK TO INCREASE INTO THE 15
TO 30 MPH RANGE OVERNIGHT.
ZAPOTOCNY
LONG TERM...SATURDAY THROUGH THURSDAY.
PRECIPITATION CHANCES WILL PROVIDE THE MAIN FORECAST CHALLENGES
THROUGH THE EARLY PART OF THIS PERIOD.
500 MB CHART FROM THIS MORNING SHOWED A STRONG AND COMPACT CLOSED
LOW JUST WEST OF SAN DIEGO. THIS FEATURE HAD 12 HOUR HEIGHT FALLS
OF AROUND 170 METERS. IT WILL CONTINUE TO TRACK QUICKLY NORTHEAST
AND SHOULD BE OVER THE EASTERN COLORADO/NORTHWEST KANSAS BORDER
AREA BY 12Z FRIDAY. AS THIS FEATURE LIFTS OUT INTO THE CENTRAL
PLAINS FRIDAY...EXPECT FAIRLY WIDESPREAD PRECIPITATION TO OCCUR.
LOW LEVELS WILL BE SLOW TO SATURATE...WITH MAIN 850 MB MOISTURE
AND INSTABILITY AXIS GENERALLY REMAINING WEST AND SOUTH OF THE
FORECAST AREA. 12Z GFS SHOWED 850 DEWPOINTS REACHING 10-12
DEGREES CELSIUS IN PARTS OF SOUTHEAST NEBRASKA DURING THE DAY.
CAN NOT RULE OUT A FEW STORMS INTO THAT AREA...BUT MAIN SEVERE
THREAT SHOULD STAY TO OUR SOUTH FRIDAY. TEMPERATURES WILL BE COOL
WITH EASTERLY WINDS...CLOUDS AND PRECIPITATION. GENERALLY STAYED
BELOW MOS GUIDANCE FOR HIGHS FRIDAY.
KEPT FAIRLY HIGH RAIN CHANCES FRIDAY NIGHT AND SOME THUNDERSTORMS
STILL SEEM POSSIBLE IN THE EVENING...ESPECIALLY OVER SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA. FAIRLY STRONG DRYING TAKES PLACE
BEHIND THE MAIN SHORTWAVE TROUGH BY LATE FRIDAY NIGHT SO EXPECT
SATURDAY TO BE MOSTLY DRY. THE 12Z ECMWF AND 12Z GFS MODEL SOLUTIONS
START TO DIVERGE BY SATURDAY NIGHT INTO SUNDAY. GFS IS MORE
AGGRESSIVE WITH PRECIPITATION SPREADING BACK INTO THE AREA FROM
THE SOUTH. GENERALLY FELT THE ECMWF WAS HANDLING THE PATTERN
BETTER THAN THE GFS...BUT COULD NOT RULE OUT GFS SOLUTION SO
BLENDED SOME OF THAT THINKING INTO GRIDS. A DIFFERENT CLOSED
LOW...ASSOCIATED WITH THE TROUGH CURRENTLY OFF THE PACIFIC
NORTHWEST...WILL MOVE INTO NORTHERN WYOMING OR SOUTHERN MONTANA BY
00Z SATURDAY. THIS SHOULD TRACK EAST TOWARD THE WESTERN DAKOTAS
THROUGH SATURDAY EVENING AND THEN LIFT NORTH THROUGH SUNDAY NIGHT.
MAIN AFFECTS FROM THAT SHOULD STAY TO OUR WEST OR SOUTH.
A WEAK TROUGH REMAINS OVER THE ROCKIES THROUGH MID WEEK...WITH
SEVERAL RIPPLES IN THE FLOW MOVING OUT ACROSS OUR AREA. THE TIMING
DIFFERENCES PERSIST THROUGH DAY 7.
MILLER
AVIATION...
18Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE FORECAST THROUGH 27/15Z. FIRST PIECE OF ENERGY
WILL LIFT ACROSS THE TAF SITES THIS AFTERNOON. MID LEVEL CLOUDS
WILL BE ON THE INCREASE MOSTLY AT FL100...BUT ALSO SOME SCT-BKN AT
FL050. DRY AIR SHOULD LIMIT WIDESPREAD PRECIPITATION. THERE MAY BE
A FEW SPRINKLES OR SHOWERS...HOWEVER DUE TO SPOTTY NATURE HAVE NOT
INCLUDED. THE STRONGER PIECE OF ENERGY WILL MOVE ACROSS THE AREA
FRIDAY. DEEP MOISTURE WILL BE AVAILABLE WITH STRONGER LIFT AND
MORE WIDESPREAD PRECIPITATION ALONG WITH LOWER MVFR CIGS POSSIBLE.
NORTHEAST WINDS WILL BECOME EAST AT 10 TO 15KTS WITH SOME GUSTS 20
TO 25KTS. TONIGHT AFTER 06Z...EAST TO SOUTHEAST WINDS WILL
INCREASE TO 15 TO 25KTS WITH GUSTS 25 TO 30KTS. MENTIONED LOW
LEVEL WIND SHEAR AT KOMA AND KLNK AFT 09Z WITH 2K WINDS INCREASING
TO 45 TO 55KTS.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
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
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 WILMINGTON NC
737 PM EDT THU APR 26 2012
.SYNOPSIS...
A COLD FRONT WILL DIP INTO THE COASTAL CAROLINAS LATE TONIGHT...
STALLING FRIDAY...THEN LIFTING NORTH SATURDAY. THE FRONT WILL
RETURN SOUTH LATE SATURDAY NIGHT AND FINALLY GET PUSHED OUT OF THE
AREA AS CANADIAN HIGH PRESSURE SURGES SOUTH ALONG THE ATLANTIC
COAST INTO MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM THURSDAY...A STRONG UPPER DISTURBANCE IS PUSHING ACROSS
VIRGINIA AND NORTHERN NORTH CAROLINA THIS AFTERNOON. ALONG THE FRONT
EDGE OF THIS DISTURBANCE THIS MORNING A SQUALL LINE CAME ROARING OUT
OF THE MOUNTAINS BUT DIED OUT AS IT CROSSED INTERSTATE 77. THE TAIL
END OF THIS UPPER DISTURBANCE HAS DEVELOPED A NEW CLUSTER OF
CONVECTION THIS AFTERNOON IN THE SC SANDHILLS BACK TO JUST SOUTH OF
CHARLOTTE. THESE NEW STORMS APPEARS TO BE LARGELY ELEVATED IN NATURE
ALTHOUGH THEY RISK BECOMING SURFACE-BASED AS THEY MOVE INTO A MORE
DEEPLY-MIXED REGION IN THE SC/NC COASTAL PLAIN WHERE DRY-ADIABATIC
LAPSE RATES EXIST FROM THE SURFACE UP THROUGH AT LEAST 5500 FT.
RISKS ASSOCIATED WITH THESE STORMS MAY TRANSITION FROM LIGHTNING AND
HAIL TO DAMAGING WINDS. FOR THE NEXT SEVERAL HOURS WE`RE FORECASTING
THIS BATCH OF STORMS TO AFFECT AREAS FROM BENNETTSVILLE AND DILLON
ACROSS SOUTHERN ROBESON COUNTY...PERHAPS MAKING IT INTO THE
WHITEVILLE AREA TOWARD 6 PM. POPS HAVE BEEN INCREASED TO 50-80
PERCENT IN THIS REGION FROM 3-6 PM.
A SECOND UPPER DISTURBANCE IN TENNESSEE AND KENTUCKY IS EXPECTED TO
FOLLOW THIS EVENING IN THE FOOTSTEPS OF OUR FIRST DISTURBANCE.
CLUSTERS OF THUNDERSTORMS ACROSS E TN INTO THE NC MOUNTAINS WILL
PUSH EAST AND INTO THE CENTRAL AND EASTERN CAROLINAS BY SUNSET. THE
LAST FEW HRRR RUNS SHOW THIS ACTIVITY MOVING EAST ACROSS THE
NORTHERN HALF OF OUR FORECAST AREA BETWEEN 7 PM AND MIDNIGHT. POPS
IN THE 30-50 PERCENT RANGE ARE FORECAST ALONG AND NORTH OF A LINE
FROM DARLINGTON...DILLON...WHITEVILLE AND BURGAW DURING THAT TIME
FRAME.
AFTER MIDNIGHT CONVECTION SHOULD PUSH EAST OF THE AREA AND BREEZY
WINDS SHOULD BEGIN TO DIE DOWN AS THE PRESSURE GRADIENT RELAXES AND
THE BOUNDARY LAYER BECOMES MORE STABLE. BY DAYBREAK A SYNOPTIC COLD
FRONT WILL BE KNOCKING ON THE DOOR FROM THE NORTH. MODELS ARE NOT IN
GOOD AGREEMENT WITH PRECISELY HOW FAR SOUTH THE BOUNDARY MOVES. THE
GFS IS THE SOUTHERNMOST SOLUTION BUT DOESN`T SEEM TOO UNREASONABLE
GIVEN ALL THE CONVECTION EXPECTED ACROSS NORTHERN AND CENTRAL NC
TONIGHT WHICH COULD HELP PUSH THE BOUNDARY SOUTH. LOWS ARE EXPECTED
TO RUN 5-10 DEGREES ABOVE NORMAL...RANGING FROM 60 INLAND TO THE MID
60S ON THE SC COAST.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...COLD FRONT WILL BE MOVING DOWN FROM THE
NORTH THROUGH OUR AREA ON FRIDAY MORNING BEFORE STALLING OUT CLOSE
TO THE NC/SC BORDER BY AFTERNOON. THE SHORTWAVE DRIVING THIS FRONT
SHIFTS OFF SHORE BY MID MORNING LEAVING MORE IN THE WAY OF
SUBSIDENCE IN ITS WAKE. THIS FRONT WILL REMAIN BISECTING OUR CWA
THROUGH FRIDAY AND WILL REMAIN THE FOCAL POINT FOR PCP. IT LOOKS
LIKE THE BEST CHC OF SHWRS WILL BE IN THE MOISTURE RICH AIR TO THE
SOUTH OF THE FRONT FROM THE NC/SC BORDER TO CAPE FEAR AND SOUTH
OVER SC EARLIER AND MOVING NORTH LATER IN THE DAY. WITH SUBSIDENCE
PRESENT EARLIER IN THE DAY...THINK WE WILL SQUEEZE OUT A DECENT
MORNING OVER MOST AREAS BUT EXPECT CLOUDS AND SHWRS/TSTMS IN
VICINITY OF FRONT AND BETTER CHC LATER IN DAY INTO OVERNIGHT HOURS
AS NEXT SHORTWAVE MOVES THROUGH.
MID TO UPPER RIDGE ALONG THE MISSISSIPPI VALLEY ON FRI WILL MOVE
EAST. FLOW ALOFT BECOMES MORE PARALLEL KEEPING FRONT IN THE
VICINITY THROUGH FRI BUT IT WILL MOVE BACK NORTH ON SATURDAY AS A
GENERAL W-SW FLOW DEVELOPS ALOFT AS SHORTWAVE MOVES THROUGH.
LATEST NAM AND GFS WERE A BIT SLOWER TO MOVE THIS BOUNDARY BACK
NORTH WHICH MAY KEEP CLOUDS AND POSSIBLE PCP IN FORECAST SAT
MORNING. THE SHALLOW COOL AIR WILL REMAIN INLAND AND NORTH WHILE
WARMER AIR PUSHES NORTH ALONG THE COAST INITIALLY. THIS
TROUGH/FRONT OVER AREA WILL MOVE NORTH SAT AFTERNOON BUT WILL GET
HELD UP ONCE AGAIN JUST NORTH OF OUR AREA BY SUNDAY MORNING.
OVERALL EXPECT A CLOUDIER AND WETTER SAT THAN IT LOOKED A FEW DAYS
BACK.
TEMPS WILL BE ANOTHER CHALLENGE. EXPECT HIGHS UP TO 10 DEGREES
COOLER TO THE NORTH VS SOUTH OF FRONT. FLORENCE AREA TO COASTAL SC
SHOULD BE IN THE MID 80S WHILE LUMBERTON AND THE NORTHERN TIER OF
CWA WILL SEE READINGS IN THE MID 70S. OVERNIGHT LOWS WILL REMAIN
WARMER WITH CLOUDS AND PCP PRESENT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...BACK DOOR COLD FRONT CROSSES SOUTH THROUGH
THE CWA SUNDAY. VERY LITTLE IN THE WAY OF MOISTURE ASSOCIATED WITH
THIS FEATURE HAS PROMPTED EVEN FURTHER REDUCTION FROM INHERITED
POP...WITH SCHC NOW CONFINED TO ONLY THE NORTHERN HALF OF THE AREA.
IF THIS DRYING PATTERN CONTINUES...WILL LIKELY NEED TO REMOVE ANY
MENTION OF SHOWERS ALTOGETHER WITH LATER UPDATES. AS THIS FRONT
MOVES SOUTH...IT WILL RESTRICT MAX TEMPS TO ONLY THE MID 70S ACROSS
THE NORTH...WITH LOWER 80S LIKELY IN THE FAR SOUTHWEST WHERE FROPA
OCCURS LATER.
VERY SIGNIFICANT MODEL DIFFERENCES EXIST NOW FOR MON/TUE WHICH
CREATE LOWERED CONFIDENCE FOR THIS PART OF THE FORECAST. GFS STILL
SHOWS A STRONG WEDGE OF HIGH PRESSURE HOLDING ACROSS THE CAROLINAS
MONDAY INTO TUESDAY...WHILE CMC/ECMWF HAVE BACKED OFF ON THIS
FEATURE. ALTHOUGH HPC CONTINUES TO FAVOR THE ECMWF...THE RECENT
CONSISTENCY OF THE GFS CANNOT BE IGNORED EVEN IF IT IS THE OUTLIER
NOW. ADMITTEDLY...IT IS CLIMATOLOGICALLY QUITE DIFFICULT TO GET A
STRONG WEDGE THIS TIME OF YEAR SO THE ECMWF SOLUTION MAY BE MORE
REALISTIC...BUT HESITATE TO MAKE ANY SIGNIFICANT CHANGES TO THIS
PORTION OF THE FORECAST DUE TO UNCERTAINTY. SO WILL JUST ADJUST
TEMPS UPWARD A BIT...BUT OTHERWISE LEAVE PRETTY MUCH UNCHANGED FOR
NOW.
BY LATE TUESDAY ANY REMNANT WEDGING...IF ANY...ERODES AS HIGH
PRESSURE DRIFTS OFFSHORE AND WARM SOUTHERLY RETURN FLOW ENVELOPS THE
AREA. THIS WILL BRING BACK WEATHER MORE TYPICAL OF EARLY MAY...WITH
TEMPS RISING TO ABOVE CLIMO WED/THU.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...TERMINALS ARE CURRENTLY VFR. THE INITIAL BATCH OF
SHOWERS AND THUNDERSTORMS HAVE ENDED...BUT WITH THE APPROACH OF A
COLD FRONT AND UPPER DISTURBANCE EXPECT ACTIVITY TO MOVE BACK INTO
THE AREA LATER THIS EVENING AND PERSIST OVERNIGHT. EXPECT ISOLATED
TO SCATTERED COVERAGE OF SHOWERS WITH ISOLATED THUNDERSTORMS. DUE
TO UNCERTAINTIES IN COVERAGE AND TIMING WILL JUST INDICATE VCSH
IN TAFS ATTM. VFR FLIGHT CONDITIONS EXPECTED OUTSIDE OF CONVECTIVE
ACTIVITY WITH TEMPO SUB-VFR CONDITIONS ASSOCIATED WITH THE
SHOWERS. THE WIND FIELD HAS BEEN SEVERELY DISRUPTED BY THIS
AFTERNOONS CONVECTIVE ACTIVITY AT LBT/ILM THIS EVENING...BUT
EXPECT WINDS TO RECOVER IN A FEW HOURS AND BE GENERALLY SOUTH TO
SOUTHWEST AT ALL TERMINALS OVERNIGHT AHEAD OF THE APPROACHING
FRONT.
BY SUNRISE ANY PRECIPITATION SHOULD END. THE COLD FRONT WILL MOVE
THROUGH ALL TERMINALS DURING THE MORNING SHIFTING WINDS TO THE
NORTHWEST. THE FRONT WILL STALL NEAR A FLO-MYR LINE BY LATE MORNING.
MVFR CEILINGS WILL BE POSSIBLE MID-MORNING TO EARLY AFTERNOON FROM
FLO-CRE/MYR...OTHERWISE VFR. WINDS WILL BECOME LIGHT NORTHEAST AT
ILM/LBT IN THE AFTERNOON...AND SOUTHEAST AT MYR/CRE. CONVECTION
SHOULD FIRE ALONG THE FRONTAL BOUNDARY FLO- MYR/CRE DURING THE
AFTERNOON.
EXTENDED OUTLOOK...SCATTERED SHOWERS AND STORMS POSSIBLE FRIDAY
AFTERNOON THROUGH THE EVENING HOURS. ISOLATED STORMS SATURDAY. VFR
SUNDAY AND MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 PM THURSDAY...LOW PRESSURE IS DEEPENING ACROSS SOUTHEAST
VIRGINIA THIS AFTERNOON AND SHOULD PUSH OUT INTO THE WESTERN
ATLANTIC THIS EVENING. THIS LOW HAS PRODUCED A TIGHTENED PRESSURE
GRADIENT BETWEEN ITSELF AND HIGH PRESSURE RIDGING WEST ACROSS THE
FLORIDA PENINSULA. STRONG SOUTHWEST WINDS SHOULD GRADUALLY DIMINISH
OVERNIGHT AS THE GRADIENT TIGHTENS...AND AS A COLD FRONT SLIDES
SOUTH TOWARD THE REGION. THIS FRONT MAY BEGIN TO MOVE INTO THE CAPE
FEAR REGION AROUND DAYBREAK FRIDAY...OTHERWISE EXPECT LARGELY
SOUTHWEST WINDS TO PREVAIL OVERNIGHT.
THUNDERSTORMS DEVELOPING IN THE CENTRAL AND WESTERN CAROLINAS WILL
MOVE EAST AND MAY BEGIN TO AFFECT THE COASTAL WATERS MAINLY NORTH OF
MYRTLE BEACH THIS EVENING. GUSTY WINDS AND LIGHTNING THE PRIMARY
EXPECTED THREATS.
WITH STRONG WINDS OVER THE PAST 12 HOURS HAVE DEVELOPED QUITE A
ROUGH SEA STATE. SEA HEIGHTS ARE BEING MEASURED AS HIGH AS 8-9 FEET
OUT AT THE FRYING PAN SHOALS BUOY...WITH 5-6 FT CLOSER TO SHORE AT
THE CORMP BUOYS. SEAS WILL GRADUALLY DIMINISH OVERNIGHT AS WINDS DIE
AWAY BUT IT WILL TAKE TIME.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...COLD FRONT WILL DROP SOUTH AND STALL NEAR
CAPE FEAR REMAINING DRAPED ACROSS AREA ON FRIDAY INTO SATURDAY.
THIS WILL CREATE LIGHTER AND MORE VARIABLE WINDS OVER THE LOCAL
WATERS. THERE WILL BE AN OVERALL DECREASE IN WINDS AND SEAS AS
GRADIENT WEAKENS OVER AREA. SEAS WILL START OUT NEAR SCA BUT WILL
DIMINISH QUICKLY THROUGH AFTERNOON DOWN TO 3 FT OR LESS BY LATE
AFTERNOON. WINDS WILL BE N-NE VEERING AROUND TO THE E-NE NORTH OF
THE FRONT AND WILL BE SOUTHERLY TO THE SOUTH OF BOUNDARY. BY SAT
AFTERNOON FRONT WILL MOVE BACK NORTH AGAIN AND A SLIGHT INCREASE
IN S WINDS WILL DRIVE SEAS BACK UP A BIT REACHING 3 TO 4 FT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...BACK DOOR COLD FRONT CROSSES THE WATERS
SUNDAY SO WINDS WILL BE LIGHT AND VARIABLE DURING FRONTAL
PASSAGE...BECOMING NE AND INCREASING TO AROUND 15 KTS LATE SUNDAY
BEHIND THE FRONT. SEAS WILL BE PREDOMINANTLY 2-4 FT THROUGH MOST OF
SUNDAY...BUILDING TO 3-5 FT LATE DUE TO THE INCREASING WINDS.
MODERATE NE WINDS PERSIST MUCH OF MONDAY BEFORE EASING AND VEERING
GRADUALLY TO THE SE TUESDAY AS HIGH PRESSURE DRIFTS OFFSHORE. SEAS
STAY ELEVATED THROUGH THE FIRST HALF OF MONDAY...3-5 FT EXCEPT IN
THE FAVORED SHADOW REGIONS SW OF FRYING PAN SHOALS. CAUTIONARY
HEADLINES APPEAR LIKELY LATE SUNDAY INTO MONDAY...BUT CONDITIONS MAY
REMAIN JUST BELOW SCA THRESHOLDS. SEAS THEN FALL BACK TO 2-4 FT LATE
MONDAY AND TUESDAY WITH AN INCREASING SE SWELL.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR AMZ254-256.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT FRIDAY FOR AMZ250-252.
&&
$$
NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...MRR
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...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 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 LUBBOCK TX
819 PM CDT THU APR 26 2012
.UPDATE...
REMAINING OUTFLOW BOUNDARIES FROM PREVIOUS CONVECTION WAS
UNSUCCESSFUL IN INITIATING STORMS. LIFT FROM THE TROUGH HAS MOVED
EAST AND NORTH OF THE AREA. REMAINING LIFT FROM THE TROUGH IS
EXPECTED TO SKIRT NORTH OF THE AREA LATER TONIGHT INTO EARLY
FRIDAY. HAVE ALSO UPDATED THE REST OF THE FORECAST TO MAINLY
REMOVE POPS.
&&
.PREV DISCUSSION... /ISSUED 630 PM CDT THU APR 26 2012/
AVIATION...
BREEZY EASTERLY WINDS WILL PERSIST OVERNIGHT AT BOTH TERMINALS.
EARLIER THUNDERSTORMS WERE CONTINUING TO DECLINE IN INTENSITY AND
ARE NOT ANTICIPATED TO AFFECT THE KCDS TERMINAL. A COLD FRONT WILL
MOVE THROUGH THE AREA BEFORE DAYBREAK INCREASING AND SHIFTING
WINDS TO THE WEST. STRONG WINDS BEHIND THIS FRONT ARE EXPECTED TO
PERSIST MUCH OF THE DAY ON FRIDAY.
PREV DISCUSSION... /ISSUED 315 PM CDT THU APR 26 2012/
SHORT TERM...
MOIST EASTERLY FLOW THIS AFTERNOON WILL TURN 180 DEGREES BY TOMORROW
MORNING AND DRY OUT BEHIND A DRYLINE AND WEAK PACIFIC COLD FRONT.
UNTIL THEN...THE FORECAST CHALLENGE REMAINS FOCUSED ON TSTRM
OPPORTUNITIES LATE THIS AFTN AND EVENING WITHIN A FAVORABLY MOIST
AND DESTABILIZING ATMOSPHERE. AS OF 20Z...THIS WINDOW DOES APPEAR TO
BE OPENING FURTHER AS THE LEADING EDGE OF HEIGHT FALLS IS NOW
ADVANCING INTO ERN NM WELL IN ADVANCE OF A TIGHTLY-WOUND UPPER LOW
IN CENTRAL AZ. VISIBLE SATELLITE CONFIRMS THIS TREND AS BOUNDARY
LAYER CUMULUS AND MID-LEVEL CLOUDS HAVE QUICKLY THICKENED BETWEEN
CLINES CORNERS AND CLOVIS. SURFACE OBSERVATIONS CLEARLY REVEAL THE
DRYLINE WILL NOT MIX AS FAR EAST AS 12Z MODELS AND RECENT RUNS OF
THE HRRR SUGGESTED...LARGELY DUE TO A SLOWER UPPER TROUGH AND ITS
SUBSEQUENT DELAY WITH WESTERLY SURFACE FLOW. SURFACE FRONT FROM
EARLIER THIS MORNING HAS ESSENTIALLY DIFFUSED...ALTHOUGH MODELS
INDICATE SOME SEMBLANCE OF THIS A FEW THOUSAND FEET ALOFT LIFTING
SLOWLY NORTH AS A WARM FRONT. LATEST RUC APPEARS THE MOST CREDIBLE
WITH THE DRYLINE SHARPENING UP NEAR HWY 385 BEFORE SUNSET INSTEAD OF
I27 AS PREVIOUSLY THOUGHT. EXODUS OF A SUBTROPICAL CIRRUS SHIELD
ACROSS THE NWRN HALF OF THE CWA HAS ALREADY PUSHED CIN TO NEAR ZERO
IN PLACES...WITH HIGH-BASED CUMULONIMBUS FOUND DEVELOPING FROM NEAR
TCC NORTHEAST TO NEAR CHANNING...AND ALSO SOUTHWARD INTO OUR WRN
COUNTIES. CAPE INCREASES MARKEDLY FARTHER EAST WHERE MOISTURE IS
SIGNIFICANTLY BETTER...SO TEND TO BELIEVE A LARGE HAIL THREAT WILL
DOMINATE AS STORMS FAVOR DISCRETE MODES...LIKELY SUPERCELLULAR
GIVEN FAVORABLE BOUNDARY-ORIENTED 0-6KM SHEAR VECTORS. RECENT SWOMCD
FULLY CONFIRMS THREAT FOR SVR CONVECTION.
AS EARLIER AFD MENTIONED...THE GREATEST COVERAGE OF CONVECTION
SHOULD TAKE AIM NORTH OF THE CWA GENERALLY ALONG AND NORTH OF THE
AXIS OF A CYCLONICALLY-CURVED UPPER JET STREAK. WILL HOWEVER
MAINTAIN ISO TSTRM MENTION MAINLY OVER OUR NRN COUNTIES THROUGH
MIDNIGHT AS THIS REGION WILL LIE NEAR THE EDGE OF DEEP ASCENT.
DRYLINE SHOULD BE OVERTAKEN BY A PACIFIC COLD FRONT BEFORE SUNRISE
FRI AT WHICH POINT BREEZY WESTERLY WINDS WILL DEVELOP...WITH DEEPER
MIXING BY MID-MORNING LIKELY SECURING SUSTAINED WLY WINDS OF 20-25
MPH. DEPARTURE OF THE UPPER TROUGH FROM SERN CO INTO NEBRASKA BY 18Z
IMPLIES A DIMINISHED GRADIENT FLOW LOCALLY...SO DESPITE MORE
UNSEASONABLE WARMTH...FIRE WEATHER CONCERNS DO NOT APPEAR ROBUST
ENOUGH FOR A FIRE WEATHER WATCH AS WINDS WILL BE DIMINISHING
THROUGHOUT THE DAY.
LONG TERM...
ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM FORECAST TODAY...WITH A
PERIOD OF UNSETTLED WEATHER POSSIBLE FROM THE LATTER HALF OF THE
WEEKEND INTO AT LEAST EARLY NEXT WEEK.
THE MID-LEVEL PATTERN THROUGH MUCH OF THE EXTENDED WILL BE DOMINATED
BY SOME SEMBLANCE OF WESTERN TROUGHING...WHICH WILL KEEP WEST TEXAS
UNDER VARIATIONS OF SOUTHWEST FLOW ALOFT. EARLY ON...A SHORTWAVE
TROUGH WILL QUICKLY LIFT NORTHWARD ACROSS THE UPPER MIDWEST AS A
CLOSED LOW MIGRATES FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH
PLAINS FROM FRIDAY INTO SATURDAY. THIS SHOULD HELP FORCE A COLD
FRONT SOUTHWARD INTO THE SOUTH PLAINS ON SATURDAY BEFORE IT STALLS
OUT LATER IN THE DAY. THE INITIAL FROPA STILL APPEARS TO BE A DRY
ONE...WITH THE BETTER LOW-LEVEL MOISTURE SHUNTED SOUTH AND EAST OF
THE AREA. HOWEVER...BY SATURDAY NIGHT...A SOUTHERLY LLJ WILL
INCREASE AND BEGIN TO DRAW BETTER AMOUNTS OF MOISTURE UP AND OVER
THE COOL DOME IN PLACE...AND THIS WAA REGIME WILL RESULT IMPROVING
CHANCES OF ELEVATED SHOWERS/STORMS. LATEST INDICATIONS ARE THAT
THE FRONT WILL GRADUALLY RETREAT NORTHWARD SATURDAY NIGHT AND
EARLY SUNDAY...WITH PERHAPS A MCS DEVELOPING TO ITS NORTH. RIGHT
NOW...IT APPEARS THE MOST FAVORED REGION FOR A POTENTIAL MCS WOULD
BE DISPLACED TO THE NORTH...ACROSS THE PANHANDLES...THOUGH THIS
COULD CHANGE DEPENDING ON THE EXACT POSITION OF THE FRONT. FOR
NOW...HAVE CURTAILED POPS TO FAVOR THE NORTHERN AND NORTHEASTERN
SECTIONS SATURDAY NIGHT AND EARLY SUNDAY...WITH MORE DEVELOPMENT
POSSIBLE ALONG THE DRYLINE /LIKELY LOCATED NEAR THE TX/NM LINE/ BY
LATER IN THE DAY SUNDAY. THE 12Z NAM DOES ATTEMPT TO FORCE THE
FRONT BACK SOUTHWARD LATER SUNDAY...LIKELY AS A RESULT OF A
REINFORCED COLD POOL FROM THE EARLY DAY MCS...BUT THESE DETAILS
REMAIN TOO ELUSIVE/UNCERTAIN TO FOLLOW ATTM. TEMPERATURES DO ALSO
REMAIN A LITTLE TRICKY THIS WEEKEND GIVEN SOME UNCERTAINTY WITH
THE FRONTAL POSITION...BUT HAVE TENDED TOWARD A COMPROMISE FOR
NOW...WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S.
EARLY NEXT WEEK WILL FEATURE A DRYLINE ROAMING THE AREA UNDERNEATH
SOUTHWEST FLOW ALOFT AND THIS PATTERN WILL KEEP AT LEAST LOW THUNDER
CHANCES IN THE FORECAST...FAVORING THE AFTERNOON AND EVENING HOURS.
TOWARD THE MIDDLE OF NEXT WEEK THE MID-LEVEL FLOW MAY TURN MORE
WESTERLY /AND MAYBE EVEN WEAKLY ANTICYCLONIC/ AND THIS WOULD TEND TO
PUSH THE BETTER MOISTURE EASTWARD AND MAKE LOW THUNDER CHANCES EVEN
LESS CERTAIN. THUS...HAVE MAINTAINED A DRY FORECAST FROM WEDNESDAY
ONWARD FOR NOW. TEMPERATURES FOR NEXT WEEK WILL AGAIN BE ON THE WARM
SIDE OF AVERAGE...WITH HIGHS GENERALLY IN THE 80S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 52 82 47 75 49 / 10 0 10 10 20
TULIA 55 85 49 75 52 / 10 0 10 10 30
PLAINVIEW 56 85 51 76 55 / 10 0 10 10 20
LEVELLAND 54 86 53 80 57 / 10 0 10 10 20
LUBBOCK 60 88 55 80 58 / 10 0 10 10 20
DENVER CITY 54 86 53 83 55 / 10 0 0 10 20
BROWNFIELD 55 88 54 82 60 / 10 0 10 10 20
CHILDRESS 63 93 56 80 59 / 10 10 10 10 30
SPUR 61 91 56 81 61 / 10 0 10 10 20
ASPERMONT 67 96 59 84 61 / 10 0 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
630 PM CDT THU APR 26 2012
.AVIATION...
BREEZY EASTERLY WINDS WILL PERSIST OVERNIGHT AT BOTH TERMINALS.
EARLIER THUNDERSTORMS WERE CONTINUING TO DECLINE IN INTENSITY AND
ARE NOT ANTICIPATED TO AFFECT THE KCDS TERMINAL. A COLD FRONT WILL
MOVE THROUGH THE AREA BEFORE DAYBREAK INCREASING AND SHIFTING
WINDS TO THE WEST. STRONG WINDS BEHIND THIS FRONT ARE EXPECTED TO
PERSIST MUCH OF THE DAY ON FRIDAY.
&&
PREV DISCUSSION... /ISSUED 315 PM CDT THU APR 26 2012/
SHORT TERM...
MOIST EASTERLY FLOW THIS AFTERNOON WILL TURN 180 DEGREES BY TOMORROW
MORNING AND DRY OUT BEHIND A DRYLINE AND WEAK PACIFIC COLD FRONT.
UNTIL THEN...THE FORECAST CHALLENGE REMAINS FOCUSED ON TSTRM
OPPORTUNITIES LATE THIS AFTN AND EVENING WITHIN A FAVORABLY MOIST
AND DESTABILIZING ATMOSPHERE. AS OF 20Z...THIS WINDOW DOES APPEAR TO
BE OPENING FURTHER AS THE LEADING EDGE OF HEIGHT FALLS IS NOW
ADVANCING INTO ERN NM WELL IN ADVANCE OF A TIGHTLY-WOUND UPPER LOW
IN CENTRAL AZ. VISIBLE SATELLITE CONFIRMS THIS TREND AS BOUNDARY
LAYER CUMULUS AND MID-LEVEL CLOUDS HAVE QUICKLY THICKENED BETWEEN
CLINES CORNERS AND CLOVIS. SURFACE OBSERVATIONS CLEARLY REVEAL THE
DRYLINE WILL NOT MIX AS FAR EAST AS 12Z MODELS AND RECENT RUNS OF
THE HRRR SUGGESTED...LARGELY DUE TO A SLOWER UPPER TROUGH AND ITS
SUBSEQUENT DELAY WITH WESTERLY SURFACE FLOW. SURFACE FRONT FROM
EARLIER THIS MORNING HAS ESSENTIALLY DIFFUSED...ALTHOUGH MODELS
INDICATE SOME SEMBLANCE OF THIS A FEW THOUSAND FEET ALOFT LIFTING
SLOWLY NORTH AS A WARM FRONT. LATEST RUC APPEARS THE MOST CREDIBLE
WITH THE DRYLINE SHARPENING UP NEAR HWY 385 BEFORE SUNSET INSTEAD OF
I27 AS PREVIOUSLY THOUGHT. EXODUS OF A SUBTROPICAL CIRRUS SHIELD
ACROSS THE NWRN HALF OF THE CWA HAS ALREADY PUSHED CIN TO NEAR ZERO
IN PLACES...WITH HIGH-BASED CUMULONIMBUS FOUND DEVELOPING FROM NEAR
TCC NORTHEAST TO NEAR CHANNING...AND ALSO SOUTHWARD INTO OUR WRN
COUNTIES. CAPE INCREASES MARKEDLY FARTHER EAST WHERE MOISTURE IS
SIGNIFICANTLY BETTER...SO TEND TO BELIEVE A LARGE HAIL THREAT WILL
DOMINATE AS STORMS FAVOR DISCRETE MODES...LIKELY SUPERCELLULAR
GIVEN FAVORABLE BOUNDARY-ORIENTED 0-6KM SHEAR VECTORS. RECENT SWOMCD
FULLY CONFIRMS THREAT FOR SVR CONVECTION.
AS EARLIER AFD MENTIONED...THE GREATEST COVERAGE OF CONVECTION
SHOULD TAKE AIM NORTH OF THE CWA GENERALLY ALONG AND NORTH OF THE
AXIS OF A CYCLONICALLY-CURVED UPPER JET STREAK. WILL HOWEVER
MAINTAIN ISO TSTRM MENTION MAINLY OVER OUR NRN COUNTIES THROUGH
MIDNIGHT AS THIS REGION WILL LIE NEAR THE EDGE OF DEEP ASCENT.
DRYLINE SHOULD BE OVERTAKEN BY A PACIFIC COLD FRONT BEFORE SUNRISE
FRI AT WHICH POINT BREEZY WESTERLY WINDS WILL DEVELOP...WITH DEEPER
MIXING BY MID-MORNING LIKELY SECURING SUSTAINED WLY WINDS OF 20-25
MPH. DEPARTURE OF THE UPPER TROUGH FROM SERN CO INTO NEBRASKA BY 18Z
IMPLIES A DIMINISHED GRADIENT FLOW LOCALLY...SO DESPITE MORE
UNSEASONABLE WARMTH...FIRE WEATHER CONCERNS DO NOT APPEAR ROBUST
ENOUGH FOR A FIRE WEATHER WATCH AS WINDS WILL BE DIMINISHING
THROUGHOUT THE DAY.
LONG TERM...
ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM FORECAST TODAY...WITH A
PERIOD OF UNSETTLED WEATHER POSSIBLE FROM THE LATTER HALF OF THE
WEEKEND INTO AT LEAST EARLY NEXT WEEK.
THE MID-LEVEL PATTERN THROUGH MUCH OF THE EXTENDED WILL BE DOMINATED
BY SOME SEMBLANCE OF WESTERN TROUGHING...WHICH WILL KEEP WEST TEXAS
UNDER VARIATIONS OF SOUTHWEST FLOW ALOFT. EARLY ON...A SHORTWAVE
TROUGH WILL QUICKLY LIFT NORTHWARD ACROSS THE UPPER MIDWEST AS A
CLOSED LOW MIGRATES FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH
PLAINS FROM FRIDAY INTO SATURDAY. THIS SHOULD HELP FORCE A COLD
FRONT SOUTHWARD INTO THE SOUTH PLAINS ON SATURDAY BEFORE IT STALLS
OUT LATER IN THE DAY. THE INITIAL FROPA STILL APPEARS TO BE A DRY
ONE...WITH THE BETTER LOW-LEVEL MOISTURE SHUNTED SOUTH AND EAST OF
THE AREA. HOWEVER...BY SATURDAY NIGHT...A SOUTHERLY LLJ WILL
INCREASE AND BEGIN TO DRAW BETTER AMOUNTS OF MOISTURE UP AND OVER
THE COOL DOME IN PLACE...AND THIS WAA REGIME WILL RESULT IMPROVING
CHANCES OF ELEVATED SHOWERS/STORMS. LATEST INDICATIONS ARE THAT
THE FRONT WILL GRADUALLY RETREAT NORTHWARD SATURDAY NIGHT AND
EARLY SUNDAY...WITH PERHAPS A MCS DEVELOPING TO ITS NORTH. RIGHT
NOW...IT APPEARS THE MOST FAVORED REGION FOR A POTENTIAL MCS WOULD
BE DISPLACED TO THE NORTH...ACROSS THE PANHANDLES...THOUGH THIS
COULD CHANGE DEPENDING ON THE EXACT POSITION OF THE FRONT. FOR
NOW...HAVE CURTAILED POPS TO FAVOR THE NORTHERN AND NORTHEASTERN
SECTIONS SATURDAY NIGHT AND EARLY SUNDAY...WITH MORE DEVELOPMENT
POSSIBLE ALONG THE DRYLINE /LIKELY LOCATED NEAR THE TX/NM LINE/ BY
LATER IN THE DAY SUNDAY. THE 12Z NAM DOES ATTEMPT TO FORCE THE
FRONT BACK SOUTHWARD LATER SUNDAY...LIKELY AS A RESULT OF A
REINFORCED COLD POOL FROM THE EARLY DAY MCS...BUT THESE DETAILS
REMAIN TOO ELUSIVE/UNCERTAIN TO FOLLOW ATTM. TEMPERATURES DO ALSO
REMAIN A LITTLE TRICKY THIS WEEKEND GIVEN SOME UNCERTAINTY WITH
THE FRONTAL POSITION...BUT HAVE TENDED TOWARD A COMPROMISE FOR
NOW...WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S.
EARLY NEXT WEEK WILL FEATURE A DRYLINE ROAMING THE AREA UNDERNEATH
SOUTHWEST FLOW ALOFT AND THIS PATTERN WILL KEEP AT LEAST LOW THUNDER
CHANCES IN THE FORECAST...FAVORING THE AFTERNOON AND EVENING HOURS.
TOWARD THE MIDDLE OF NEXT WEEK THE MID-LEVEL FLOW MAY TURN MORE
WESTERLY /AND MAYBE EVEN WEAKLY ANTICYCLONIC/ AND THIS WOULD TEND TO
PUSH THE BETTER MOISTURE EASTWARD AND MAKE LOW THUNDER CHANCES EVEN
LESS CERTAIN. THUS...HAVE MAINTAINED A DRY FORECAST FROM WEDNESDAY
ONWARD FOR NOW. TEMPERATURES FOR NEXT WEEK WILL AGAIN BE ON THE WARM
SIDE OF AVERAGE...WITH HIGHS GENERALLY IN THE 80S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 52 82 47 75 49 / 20 0 10 10 20
TULIA 55 85 49 75 52 / 20 0 10 10 30
PLAINVIEW 56 85 51 76 55 / 20 0 10 10 20
LEVELLAND 54 86 53 80 57 / 10 0 10 10 20
LUBBOCK 60 88 55 80 58 / 10 0 10 10 20
DENVER CITY 54 86 53 83 55 / 10 0 0 10 20
BROWNFIELD 55 88 54 82 60 / 10 0 10 10 20
CHILDRESS 63 93 56 80 59 / 20 10 10 10 30
SPUR 61 91 56 81 61 / 10 0 10 10 20
ASPERMONT 67 96 59 84 61 / 10 0 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
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
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...UPDATED
NWS PUEBLO CO
1059 PM MDT THU APR 26 2012
.AVIATION...MOST OF THE HEAVIER TS ACTIVITY HAS MOVED E OF THE I-25
CORRIDOR THIS EVENING. THE TAF SITES COULD SEE BRIEF MVFR
CONDITIONS IN SHRA THRU ABOUT 12Z BEFORE GRADUAL CLEARING OCCURS.
AN ISOLATED TS CANNOT BE RULED OUT THRU ABOUT 09Z...BUT
PROBABILITY IS LOW. TOMORROW...MAIN CONCERN WILL BE GUSTY W
WINDS...WHICH COULD EXCEED 30 KTS AT TIMES AT ALL THE TAF SITES
THROUGH THE DAY. ROSE
&&
.PREV DISCUSSION... /ISSUED 526 PM MDT THU APR 26 2012/
AVIATION...THERE IS APPROXIMATELY A 50 PERCENT CHANCE OF A THUNDERSTORM
AFFECTING THE TAF SITES BETWEEN NOW AND 06Z. WIDELY SCT SHOWERS
AND ISOLD TS CONTINUE TO MOVE FROM THE SW TO NE AT APPROXIMATELY
30 KT. SHOWERS AND TS WILL PRODUCE OCCASIONAL STRONG WIND GUSTS
FROM THE W-SW...WITH GUSTS TO 40-50 KT POSSIBLE. BRIEF IFR-MVR
CONDITIONS ARE POSSIBLE...ALONG WITH SMALL HAIL. STRONGER STORMS
WILL BE POSSIBLE E OF THE I-25 CORRIDOR THIS EVENING. STORMS COULD
CONTINUE TO DEVELOP E AND N OF KPUB-KCOS AS LATE AS 06-09Z.
NOTE THAT WINDS WILL BE QUITE ERRATIC THIS EVENING AT KPUB AND
KCOS...AS LOW LEVEL WINDS ARE FROM THE E-SE WHILE STORMS CONTINUE
TO TRANSFER W-SW WINDS TO THE SURFACE. SO...EVEN AWAY FROM
STORMS...WINDS WILL BE QUITE VARIABLE THIS EVE. 44
PREV DISCUSSION... /ISSUED 205 PM MDT THU APR 26 2012/
SHORT TERM...
(TONIGHT AND FRIDAY)
.MAIN FORECAST CONCERNS REVOLVE AROUND SEVERE POTENTIAL FOR
PORTIONS OF THE SOUTHEAST PLAINS THROUGH THE OVERNIGHT HOURS...
COMPACT CLOSED LOW CIRCULATION ACROSS AZ WILL CONTINUE TO LIFT TO
THE NORTHEAST ACROSS SOUTHERN AND SOUTHEAST COLORADO BETWEEN 06Z AND
12Z. SE SFC WINDS HAVE ADVECTED LOWER 50 DEW POINTS INTO BACA
COUNTY...WITH 40S ALONG THE ARKANSAS RIVER TO THE NORTH.
MEANWHILE...SOUTHWEST WINDS HAVE DROPPED DEW POINTS INTO THE 20S
ACROSS THE HIGH VALLEYS...WITH DEW POINTS DROPPING ACROSS THE NRN
RATON MESA AND PALMER DIVIDE AS DRY LINE TAKES SHAPE. MODELS STILL
PAINT THE SCENARIO OF A COUPLE OF WAVES OF CONVECTION DEVELOPING
ACROSS THE MOUNTAINS AND MOVING OFF INTO THE SOUTHEAST PLAINS.
FIRST WAVE IS CURRENTLY DEVELOPING ACROSS THE MTS NOW...AND EXPECT
CONVECTION TO DEVELOP ALONG THE SFC TROF/DRY LINE BY 20-21Z. SPC
MESO ANALYSIS CURRENTLY SHOWING CAPES OF AROUND 1000 TO NEAR 1500
J/KG ACROSS THE SOUTHEAST PLAINS WITH DEEP LAYER SHEARS RUNNING
AROUND 40-50 KTS. HRRR...RUC13...AND NAM12 MIX THE DEW POINTS OUT
ALONG THE I-25 CORRIDOR BACK INTO THE 30S...THOUGH HANG TOUGH WITH
THE 40S-LOWER 50 DEW POINTS ACROSS THE SOUTHEAST COUNTIES OF
KIOWA...BENT...PROWERS...AND BACA...AS WELL AS EASTERN PORTIONS OF
CROWLEY...OTERO...AND LAS ANIMAS COUNTIES. INITIALLY LCLS WILL START
OUT RATHER HIGH...WITH THE PROXY T/TD SPREADS RUNNING AROUND 30
DEGREES ACROSS THIS REGION. HOWEVER...WITH THE APPROACH OF THE
UPPER TROF...STRENGTHENING SOUTHEASTERLY WINDS WILL ADVECT 40 DEW
POINTS BACK INTO THE NRN I-25 CORRIDOR...WITH 50S TO LOWER 60 DEW
POINTS ACROSS THE SOUTHEAST PLAINS. COUPLED WITH COOLING TEMPS
ALOFT WITH INCOMING SYSTEM...THIS SHOULD AMP UP CAPE VALUES TO
BETWEEN 1500-2500 J/KG...WITH HIGHEST VALUES ACROSS BACA COUNTY BY
06Z. HELICITIES INCREASE TO 500+ M2/S2 BY 06Z WITH FORCING FROM THE
SYSTEM LIKELY TO WEAKEN OR BREAK THROUGH WHATEVER CAP REMAINS.
THUS...SEVERE WEATHER EVENT LOOKS TO START OUT AS A LARGE HAIL...AND
DAMAGING WIND SCENARIO THIS AFTERNOON...AND EVOLVE TO INCLUDE AN
ISOLATED TORNADO POTENTIAL AFTER 9 PM ACROSS THE FAR EASTERN
COUNTIES. THIS ATYPICAL LATE NIGHT TORNADO THREAT FOR THIS REGION
SHOULD LAST UNTIL AROUND 2 AM. STILL THINK THE MAIN THREAT AREA
WILL EXTEND EAST OF A LINE FROM LIMON...TO LA JUNTA...TO KIM.
THOUGH IF RUC IS CORRECT IN SPREADING 40 TO LOWER 50 DEW POINTS BACK
WESTWARD INTO THE I-25 CORRIDOR AFTER THE FIRST ROUND OF AFTERNOON
THUNDERSTORMS...THEN PLENTY OF MOISTURE WILL BE AVAILABLE TO BOOST
CAPES UP FOR THE I-25 CORRIDOR FROM AROUND PUB NORTHWARD FOR THE 2ND
ROUND OF THUNDERSTORMS WHICH SPREADS OFF THE SOUTHEAST MOUNTAINS
DURING THE LATE EVENING. IF THIS OCCURS...THEN HAIL TO NEAR 1 INCH
IN DIAMETER ALONG WITH DAMAGING WINDS MAY BE POSSIBLE FOR KCOS AND
KPUB AS WELL. WILL CONTINUE TO MONITOR THIS POTENTIAL AS SCENARIO
EVOLVES.
ACROSS THE REMAINDER OF THE AREA...WIDESPREAD SHOWERS AND
THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS THIS AFTERNOON WITH
SNOW LEVELS DROPPING ACROSS THE MOUNTAINS DURING THE EVENING WHEN
BEST FORCING WITH UPPER LEVEL SYSTEM MOVES THROUGH. COULD SEE
ANYWHERE FROM 2 TO 6 INCHES OF SNOW ACROSS THE HIGHER PEAKS...WITH
MAJORITY OF SNOWFALL ABOVE 10KFT.
PRECIPITATION WILL LIFT OFF TO THE NORTHEAST WITH THE PARENT UPPER
LOW ON FRIDAY WITH PRECIPITATION TAILING OFF ACROSS THE
OROGRAPHICALLY FAVORED NORTHWEST FACING SLOPES OF THE SAWATCH AND
MOSQUITOS IN THE MORNING. COULD ALSO SEE A PERIOD OF WRAP AROUND
PCPN ACROSS THE SOUTHEAST PLAINS DURING THE EARLY MORNING...BUT THIS
SHOULD DIMINISH BY AFTERNOON. OTHERWISE...COOLER TEMPERATURES FOR
FRIDAY...THOUGH WITH GUSTY NORTHWEST TO WEST WINDS BEHIND THE
DEPARTING SYSTEM...DEEP MIXING WILL OFFSET THE COOLING ALOFT SOME TO
STILL YIELD TEMPS IN THE 70S. -KT
LONG TERM...
(FRIDAY NIGHT THROUGH THURSDAY)
FRIDAY NIGHT AND SATURDAY NIGHT...CLOSED UPPER LOW OVER NORTHWEST
WYOMING EARLY FRIDAY EVENING MEANDERS INTO THE WESTERN DAKOTAS
THROUGH SATURDAY NIGHT. AT THE SURFACE...UPSLOPE FLOW CONTINUES ON
THE SOUTHEAST CO PLAINS. NAM BREAKS OUT PRECIPITATION ALONG THE
SOUTHEAST MOUNTAINS SATURDAY EVENING...BUT THEN PRECIPITATION AREAS
SHIFT INTO NORTHEAST COLORADO AND FAR SOUTHEASTERN CO. GFS DOESN`T
HAVE MUCH QPF OVER THE MOUNTAINS...BUT HIGHLIGHTS NORTHEAST AND FAR
SOUTHEAST CORNER OF THE STATE LATE SATURDAY EVENING. GIVEN THE
UPSLOPE FLOW...COOL AIR ALOFT AND STEEP LAPSE RATES...KEPT SOME LOW
POPS IN ALONG THE MOUNTAINS AND SPREAD EASTWARD ONTO THE PLAINS
SATURDAY NIGHT. TEMPERATURES SATURDAY SHOULD BE FAIRLY COOL. KEPT
THE PLAINS IN THE MID 50S TO MID 60S FOR HIGHS DESPITE A LARGE
SPREAD IN THE GUIDANCE HIGHS.
SUNDAY AND SUNDAY NIGHT...GFS/ECMWF STILL BULLISH WITH PRECIPITATION
DEVELOPING ACROSS THE SOUTHEAST PLAINS SUNDAY EVENING WITH SHORT
WAVE MOVING ACROSS SOUTHERN COLORADO. NOT AS COOL WITH HIGHS WARMING
INTO THE LOWER 60S TO LOWER 70S ON THE PLAINS.
MONDAY-TUESDAY...GFS/ECMWF BOTH CONTINUE TO SHOW WEST TO
SOUTHWEST FLOW ALOFT OVER COLORADO EARLY IN THE WORK WEEK AHEAD OF
A STRONGER TROF PROGGED TO MOVE THROUGH WY WEDNESDAY. DESPITE
WARMER AND DRIER AIR MOVING INTO THE FORECAST AREA...MODELS SHOW
SOME MID LEVEL MOISTURE AND A FEW WEAK WAVES TRIGGERING
SHOWERS/THUNDERSTORMS OVER THE MOUNTAINS.
WEDNESDAY-THURSDAY...UPPER LEVEL SHORTWAVE TROF MOVES EAST ACROSS WY
WEDNESDAY. AT THE SURFACE...COLD FRONT MOVES SOUTHEAST THROUGH THE
PLAINS WEDNESDAY NIGHT. DRY LOW LEVEL AIRMASS ON THE PLAINS KEEPS SHOWER
ACTIVITY TIED TO THE MOUNTAINS. TROF AXIS SHIFTS EAST INTO THE
PLAINS STATES WITH RIDGE BUILDING OVER CO ON THURSDAY. 40
AVIATION...
A COUPLE OF ROUNDS OF -TSRA MAY AFFECT KCOS AND KPUB TAF SITES...ONE
LATE THIS AFTERNOON...AND ANOTHER DURING THE EVENING AS THE POTENT
UPPER LEVEL STORM SYSTEM MOVES THROUGH THE REGION. FIRST ROUND OF
THUNDERSTORMS WILL PRODUCE ERRATIC GUSTY WINDS UP TO 40 KTS...ALONG
WITH LIGHTNING AND BRIEF HEAVY RAINFALL. THE 2ND ROUND WHICH WILL
SPREAD OFF THE MTNS INTO THE TAF SITES AROUND/AFTER 02Z...COULD BE
STRONGER WITH THE POTENTIAL TO PRODUCE SOME SMALL HAIL UP TO 1 INCH
IN DIAMETER AS WELL AS GUSTY ERRATIC WINDS. THUNDERSTORMS SHOULD
END FOR BOTH KPUB AND KCOS AROUND 06Z WITH NORTH WINDS GUSTING TO 25
TO 30 KTS. BEST WINDOW FOR -TSRA AT KALS WILL BE FROM
01Z-04Z...WITH A ROUND OF GUSTY WINDS...AND LIGHTNING AND BRIEF
MODERATE RAINFALL THE MAIN THREATS. MTN AREAS WILL SEE WIDESPREAD MTN
OBSCURATIONS THROUGH THE EVENING WITH POTENTIAL FOR 2-6 INCHES OF
SNOW DURING THE OVERNIGHT HOURS ACROSS THE HIGHER PEAKS. GUSTY
NORTH TO NW WINDS WILL CONTINUE AT THE TAF SITES THROUGH
FRIDAY...WITH VFR CONDITIONS. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
44/10
AREA FORECAST DISCUSSION
NWS MIAMI FL
415 AM EDT FRI APR 27 2012
.DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
...ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
&&
.AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
&&
.MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
&&
.FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 74 82 72 / - 10 40 30
FORT LAUDERDALE 81 73 83 71 / - 30 50 50
MIAMI 82 73 82 70 / 10 40 50 50
NAPLES 86 67 87 69 / - 10 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...14/MJB
AREA FORECAST DISCUSSION
NWS PEACHTREE CITY GA
336 AM EDT FRI APR 27 2012
.SHORT TERM /TODAY THROUGH SATURDAY/...
WEAK NORTHWESTERLY FLOW ALOFT HELPED A WEAK SURFACE COLD FRONT
MOVE TO THE NORTHERN DOORSTEP OF GEORGIA...AND STALL THERE. THIS
WILL SERVE AS A FOCUS FOR AFTERNOON CONVECTION THIS AFTERNOON...
ALTHOUGH THERE IS GREAT MODEL DISPARITY REGARDING THE AREAL
COVERAGE AND ACCUMULATION. NAM AND SREF ARE FAR MORE AGGRESSIVE
WITH LATE AFTERNOON THUNDERSTORMS FOR NORTH GEORGIA...BUT
ECMWF...GFS AND HRRR HAVE FAR LESS COVERAGE AND LIGHTER
ACCUMULATIONS. WILL SIDE WITH THE LESS AGGRESSIVE SOLUTIONS FOR
NOW...BUT THIS WILL NEED TO BE WATCHED. EXPECTING WIDESPREAD
MORNING STRATUS WHICH WILL INHIBIT HEATING...SO LATER CONVECTIVE
INITIATION SEEMS REASONABLE. CENTRAL GEORGIA LOOKS LIKE IT WILL
ESCAPE THE PRECIP CHANCES FOR THE SHORT-TERM. MOS TEMPS LOOK
GOOD...SO WILL NOT STRAY FROM GUIDANCE.
27
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
EXTENDED BEGINS WITH RIDGING BUILDING IN ALOFT AND SURFACE HIGH
PRESSURE OVER THE WESTERN ATLANTIC RIDGING INTO THE SOUTHEAST. THE
MAIN FLOW...ALONG WITH WEAK EMBEDDED IMPULSES...REMAINS JUST TO OUR
NORTH ROUNDING THE TOP OF THE RIDGE. WITH INCREASING THICKNESSES
AND MOISTURE...THE GFS REALLY INCREASES TEMPS ON SUNDAY...
FORECASTING RECORD OR NEAR-RECORD HIGHS IN THE UPPER 80S AND LOWER
90S. THE NAM HOWEVER REMAINS 8-10 DEGREES COOLER AND IS SIMPLY NOT
AS STRONG WITH THE RIDGING ALOFT. THE ECMWF SEEMS TO SUPPORT THE
GFS/S SOLUTION...SO OVERALL HAVE TAKEN A BLEND TO AVOID A DRAMATIC
SWING FROM YESTERDAY/S FORECAST BUT HAVE LEANED TOWARD THE WARMER
GFS. THIS WARMING TREND CONTINUES INTO THE EARLY PART OF THE WEEK
WITH THE 00Z GFS MUCH WARMER THAN THE 12Z RUN YESTERDAY...AND
WARMER THAN THE ECMWF IS IMPLYING. HAVE AGAIN TAKEN A BLEND...
TRYING TO ACCOUNT FOR RUN-TO-RUN DIFFERENCES AND FACTORING IN THE
ECMWF SOLUTION. OVERALL THOUGH TEMPS REMAIN ABOVE NORMAL THROUGH
THE PERIOD.
AS FOR POPS...THE EXTENDED LOOKS MOSTLY DRY...THOUGH AS THE UPPER
RIDGE BEGINS TO BREAK DOWN BY MONDAY NIGHT MOISTURE WILL BE ABLE
TO WORK FIRST INTO NORTH GEORGIA AND THEN FURTHER SOUTH. POPS
REMAIN SLIGHT CHANCE AT BEST BUT WITH A TYPICAL SUMMERLIKE DIURNAL
TREND TO THE CONVECTIVE POTENTIAL. BOTH THE GFS AND ECMWF WANT TO
BRING MOISTURE FROM THE ATLANTIC OVER FLORIDA AND EVENTUALLY INTO
PARTS OF GEORGIA...WITH THE GFS FASTER AND MORE IMPRESSIVE WITH
THE MOISTURE AMOUNTS. OF COURSE...THE GFS IS LIKELY OVERDONE WITH
THIS BUT THE TRENDS WILL HAVE TO BE MONITORED THROUGH SUBSEQUENT
FORECASTS.
TDP
&&
.AVIATION...
06Z UPDATE...
WIDELY SCATTERED SHOWERS WILL TRICKLE ACROSS FAR NORTH GA THROUGH
THE EARLY MORNING BUT NOT EXPECTED TO IMPACT TAF SITES. MORNING MVFR
CIGS LIKELY ACROSS MOST SITES AND WILL QUICKLY LIFT BY 15Z.
AFTERNOON CONVECTION A CONCERN...BUT AREAL COVERAGE APPEARS LIMITED
PER ALL MODELS EXCEPT NAM SO WILL NOT MENTION IN TAFS AT THIS TIME.
MAY AUGMENT THIS AT 12Z. LIGHT WEST WINDS FOR THE DURATION OF THE
PERIOD.
//ATL CONFIDENCE...06Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS...WITH MODERATE CONFIDENCE ON
AFTERNOON TSRA COVERAGE.
27
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 83 59 85 60 / 40 20 10 5
ATLANTA 80 62 84 63 / 30 10 10 5
BLAIRSVILLE 78 55 81 54 / 20 20 10 10
CARTERSVILLE 79 58 87 57 / 30 20 20 10
COLUMBUS 84 61 86 60 / 5 10 5 5
GAINESVILLE 81 61 85 61 / 40 20 10 10
MACON 85 58 86 58 / 20 5 5 5
ROME 83 59 87 58 / 30 20 20 10
PEACHTREE CITY 81 56 87 56 / 20 10 10 5
VIDALIA 86 64 88 64 / 10 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1234 AM CDT FRI APR 27 2012
...UPDATED AVIATION SECTION...
.SYNOPSIS...
ISSUED AT 142 PM CDT THU APR 26 2012
EARLY THIS AFTERNOON...THE WATER VAPOR SATELLITE LOOP SHOWED THE
CENTER OF A COMPACT AND INTENSE UPPER LOW OVER WESTERN ARIZONA. A
FEW LIGHTNING STRIKES WERE NOTED JUST AHEAD OF THE INTENSE MID LEVEL
POTENTIAL VORTICITY CENTER TIED TO THE LOW. SIGNIFICANT MID LEVEL
DRYING ON WV LOOP WAS BEGINNING TO ADVANCE EASTWARD TOWARD
WESTERN/CENTRAL NEW MEXICO. 12Z RAOB ANALYSIS REVEALED 140 TO 170
METER HEIGHT FALLS AT 500MB ACROSS FAR SOUTHERN CALIFORNIA WHEN THE
LOW WAS CENTERED NEAR SAN DIEGO EARLIER THIS MORNING. IN THE LOW
LEVELS...A SURFACE LOW WAS POSITIONED ALONG THE RED RIVER NEAR
WICHITA FALLS, TX. THERE WAS A POOL OF SIGNIFICANT MOISTURE AT THE
SURFACE IN THE EASTERLY FLOW NORTH OF THE SURFACE LOW OVER MUCH OF
CENTRAL/SOUTHERN OKLAHOMA WITH 70 DEGREE DEWPOINTS COMMON AS OF
MIDDAY. THE EASTERLY SURFACE WINDS WERE PULLING MID 60S DEWPOINTS AS
FAR NORTHWEST AS LEFORS, TX IN THE EASTERN TEXAS PANHANDLE. THE
EAST-SOUTHEAST WINDS CONTINUED TO ADVECT THIS MOISTURE NORTHWESTWARD
DEEPER INTO THE PANHANDLES.
&&
.SHORT TERM...(THIS EVENING THROUGH DAYBREAK FRIDAY)
ISSUED AT 250 PM CDT THU APR 26 2012
SEVERE WEATHER TONIGHT IS THE MAIN CHALLENGE IN TERMS OF A) TIMING,
B) CONVECTIVE MODE, C) MAIN HAZARDS. THE EVENT IS COMING INTO A BIT
BETTER FOCUS NOW THAT THE EXPECTED BEGINNING OF THE SEVERE WX EVENT
FOR SOUTHWEST KS IS 6-9 HOURS AWAY (AS OF 1930 UTC). SURFACE
DEWPOINTS WILL BE INCREASING NORTHWESTWARD THROUGH THE EVENING WITH
MOIST AXIS EXPECTED TO BE FROM WESTERN OKLAHOMA PANHANDLE INTO
EASTERN TEXAS PANHANDLE WITH 60F ISODROSOTHERM NOSING UP INTO THE
GUYMON, OK AREA BY 03Z. THIS YIELDS ABOUT 1800-2400 J/KG SBCAPE.
THE STRONGEST SURFACE FORCING AT THIS TIME WILL BE JUST WEST OF THE
INSTABILITY AXIS AND CONVECTION SHOULD BE ONGOING FROM SOUTHEAST
COLORADO DOWN INTO THE NORTHWESTERN TEXAS PANHANDLE. AT LEAST THIS
IS HOW THE LATEST RUC13 MODEL IS PLAYING THIS OUT IN THE CONVECTIVE
QPF FIELDS, WHICH MAKES PHYSICAL SENSE GIVEN WHERE THE FORCING IS AT
THAT TIME. THE THING THAT REALLY HAS US CONCERNED IS THE DEGREE OF
SHEAR IN THE 0-1KM AGL LAYER. IN ADVANCE OF THE SMALL SCALE UPPER
LOW...THE AGEOSTROPHIC RESPONSE IN THE LOW LEVELS WILL REALLY BE
MAXIMIZED FROM 03-09Z TONIGHT...AND THE 0-1KM AGL HELICITY WILL
EXCEED 300 M2/S2 OVER A LARGE AREA OF SOUTHWEST KANSAS. THE 0-1KM
ENERGY-HELICITY INDEX WILL REACH THE 4 TO 5 LEVEL, WHICH IS
EXTREMELY HIGH AND MORE THAN ENOUGH TO SUPPORT SIGNIFICANT LOW LEVEL
ROTATION IN THE STRONGEST STORMS...INCLUDING TORNADOES. CONVECTIVE
MODE IS THE REAL CHALLENGE. HOW LONG WILL THE SUPERCELL PHASE
LAST? THE EARLY STORMS COMING OUT OF SOUTHEAST COLORADO WILL MOST
LIKELY BE MORE SCATTERED WITH SOME DISTANCE STILL FROM THE STRONGEST
500-700MB COOLING AND MID LEVEL POTENTIAL VORTICITY (PV) ADVECTION.
WHEN THE "WALL OF FORCING" COMES OUT WITH THE INTENSE MID LEVEL COLD
ADVECTION AND PV ADVECTION...THE MODE WILL MOST LIKELY TRANSITION TO
A QUASI-LINEAR CONVECTIVE SYSTEM (QLCS). WILL HAVE TO REALLY WATCH
OUT FOR QLCS TORNADO EVENTS WHICH COULD BE SHORT-LIVED AND DIFFICULT
TO WARN FOR WITH MUCH LEAD TIME GIVEN THE CHARACTERISTICS OF THIS
TIME OF CONVECTIVE MODE AND THE ASSOCIATED LACK OF INTENSE MID LEVEL
MESOCYCLONES. ANOTHER QUESTION IS HOW FAR SOUTH THIS THREAT WILL
EXTEND INTO SOUTHWEST KANSAS. SEVERAL OF THE MODELS, MAINLY THE
LARGER-SCALE MODELS, INDICATE FAIRLY ROBUST CONVECTIVE QPF AS FAR
SOUTH AS THE OKLAHOMA BORDER BETWEEN 06-12Z. WILL PROBABLY EXTEND
LIKELY POPS DOWN CLOSE TO THE OKLAHOMA BORDER GIVEN THIS. THE
SEVERE WEATHER THREAT WILL CONTINUE ALL NIGHT AND THROUGH 12Z WITH
THE 09-12Z THREAT AREA SHIFTING NORTHEAST TOWARD THE
WAKEENEY-HAYS-LACROSSE AREAS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 353 PM CDT THU APR 26 2012
STORM CHANCES WILL PERSIST IN CENTRAL KANSAS AROUND HAYS THROUGH 20Z
SINCE THE UPPER-LEVEL TROUGH AND ASSOCIATED SURFACE LOW WILL STILL
BE IN THIS AREA THROUGH EARLY AFTERNOON. AS DISCUSSED IN THE SHORT TERM
SECTION, THESE STORMS COULD BE SEVERE. IF STORMS PERSIST LONG ENOUGH
FOR DAYTIME HEATING TO LEAD TO HIGHER CAPE, THEN VERY LARGE HAIL
WOULD BE POSSIBLE AND POSSIBLY A TORNADO. SURFACE WINDS WILL BE
STRONG BEHIND THIS SYSTEM TOMORROW. A WIND ADVISORY WAS ISSUED FOR
MUCH OF SOUTHWEST KANSAS.
AFTER THIS SYSTEM PASSES, THE ASSOCIATED COLD FRONT WILL PASS
THROUGH KANSAS AND THEN STALL OUT ACROSS CENTRAL OKLAHOMA. THE
UPSTREAM SYSTEM THAT CAUSED THE AFOREMENTIONED SYSTEM TO EJECT ACROSS
THE PLAINS WILL HANG BACK OVER THE ROCKIES THROUGH SUNDAY AND
MONDAY. THE ASSOCIATED JET STREAK WILL BE SITUATED ACROSS THE
ROCKIES AND INTO KANSAS THROUGH THIS PERIOD. A WARM ADVECTION
PATTERN WILL DEVELOP AHEAD OF THIS TROUGH. THE GFS/GEM/UKMET
INDICATE QUITE A BIT OF PRECIPITATION ON THE COOL SIDE OF THE FRONT
IN SOUTHWEST KANSAS. HOWEVER, THE ECMWF SCENARIO OF DEVELOPING
WIDESPREAD THUNDERSTORMS ALONG THE FRONT OVER OKLAHOMA AND SOUTH
CENTRAL KANSAS COULD PREVENT SIGNIFICANT RAINFALL FURTHER NORTH.
HOWEVER, 20-40% THUNDERSTORM CHANCES WERE MAINTAINED FROM SATURDAY
NIGHT THROUGH MONDAY GIVEN THE UNCERTAINTY. CLOUDS AND POSSIBLE
PRECIPITATION CHANCES TO THE NORTH OF THE FRONT WILL PROBABLY KEEP
HIGH TEMPERATURES IN THE 60S TO LOWER 70S WITH LOWS IN THE 40S AND
50S.
BY TUESDAY AND WEDNESDAY, THE NEXT JET STREAK WILL BE MOVING ACROSS
THE ROCKIES AND APPROACHING THE CENTRAL HIGH PLAINS. FRONTOLYSIS
WILL OCCUR OVER OKLAHOMA, WITH ANOTHER FRONT DEVELOPING ACROSS THE
NORTHERN OR CENTRAL PLAINS. A DRYLINE AND SURFACE FRONT WILL
INTERSECT SOMEWHERE ACROSS THE CENTRAL HIGH PLAINS REGION.
THUNDERSTORMS CANNOT BE RULED OUT EITHER DAY AS 60F DEWPOINTS
WILL BE IN PLACE AHEAD OF THE DRYLINE. IT WILL BE WARMER BY THIS
TIME, WITH HIGHS IN THE UPPER 70S AND 80S AND LOWS IN THE 50S TO
LOWER 60S. THE HIGHEST MINIMUM TEMPERATURES, AS IS TYPICAL, WILL BE
IN SOUTH CENTRAL KANSAS WHERE DEWPOINTS WILL BE HIGHER.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1234 AM CDT FRI APR 27 2012
AN AREA OF SURFACE LOW PRESSURE WILL MOVE OUT OF EASTERN COLORADO
AND INTO NORTHWESTERN COLORADO OVERNIGHT. THIS WILL INCREASE
THUNDERSTORM CHANCES OVERNIGHT. VFR CONDITIONS WILL CHANGE TO MVFR
TO IFR CONDITIONS AS THESE THUNDERSTORMS PASS OVER THE TERMINALS.
WINDS WILL GENERALLY BE FROM THE SOUTHEAST OVERNIGHT SHIFTING TO
THE SOUTH BY SUNRISE. WIND SPEED WILL QUICKLY INCREASE TO AROUND
20 KNOTS AS THIS LOW APPROACHES. GUSTS OVER 30 KNOTS CAN NOT BE
RULED OUT. A COLD FRONT ASSOCIATED WITH THE AFOREMENTIONED LOW
WILL MOVE THROUGH THE AREA TOMORROW MORNING SHIFTING THE WINDS TO
THE NORTHWEST AND INCREASE WINDS TO AROUND 25 KNOTS WITH GUSTS
AROUND 35 KNOTS. CLEAR SKIES AND VFR CONDITIONS ARE ANTICIPATED
BEHIND THIS SYSTEM.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 45 69 46 63 / 0 0 40 30
GCK 43 68 45 62 / 0 0 30 30
EHA 43 68 44 65 / 0 0 30 30
LBL 45 69 46 65 / 0 0 40 30
HYS 43 67 44 61 / 0 0 30 30
P28 51 71 48 63 / 0 0 40 40
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 10 AM CDT /9 AM MDT/ THIS MORNING TO 8 PM CDT
/7 PM MDT/ THIS EVENING FOR KSZ043>045-061>065-075>080-086>088.
&&
$$
SHORT TERM...UMSCHEID
LONG TERM...FINCH
AVIATION...HOVORKA 42
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1149 PM CDT THU APR 26 2012
...UPDATE TO AVIATION...
.DISCUSSION...
SHORT TERM (TODAY THROUGH FRIDAY)...
19Z WATER VAPOR SHOWS A SHORTWAVE LIFTING EAST THROUGH AZ WITH A
LONG WAVE TROUGH OVER THE PACIFIC NORTHWEST. MID LEVEL RIDGING
REMAINS OVER THE CENTRAL PLAINS. AT THE SFC 19Z OBS SHOWED RIDGING
THROUGH MUCH OF KS WITH A FRONTAL BOUNDARY NEAR THE RED RIVER
VALLEY. A BAND OF LIGHT SHOWER ACTIVITY HAS SET UP WITHIN A NARROW
AXIS OF ISENTROPIC UPGLIDE ACROSS CENTRAL KS.
FOR THIS AFTERNOON AND THIS EVENING...THE RUC AND NAM SHOW THE
NARROW AXIS OF ISENTROPIC LIFT ON THE 310K SFC GRADUALLY LIFTING
NORTH AND EAST. BECAUSE OF THIS HAVE INCLUDED SOME SCATTERED SHOWERS
ACROSS NORTH CENTRAL KS WERE MID LEVEL MOISTURE IS A LITTLE BETTER.
THE NEXT SHIFT WILL NEED TO WATCH THE EASTWARD PROGRESSION. BUT
FOR NOT THINK SHOWERS WILL HAVE A HARD TIME MOVING EAST DUE TO A
LITTLE MORE DRY AIR IN THE MID LEVELS.
OVERNIGHT...THE SHORTWAVE OVER AZ WILL LIFT OUT OF THE SOUTHERN
ROCKIES AND MOVE INTO SOUTHERN NEB THROUGH THE DAY FRIDAY. THIS WAVE
IS EXPECTED TO PROVIDE THE FORCING TO SPARK CONVECTION LATE TONIGHT
AND THROUGH THE DAY FRIDAY. AT THIS POINT IT LOOKS LIKE THERE COULD
BE ELEVATED CONVECTION FORM DURING THE MORNING HOURS AND LIFT ACROSS
NORTHEAST KS. BOTH THE NAM AND GFS SHOW A NARROW WARM SECTOR
DESTABILIZING BY THE LATE MORNING OR EARLY AFTERNOON WITH SURFACE
BASED CAPES ON THE ORDER OF 1000 TO 1500 J/KG. WHILE A LITTLE ON THE
MARGINAL SIDE...DEEP LAYER SHEER OF 50 KTS WOULD BE SUFFICIENT FOR
STORMS IN THE WARM SECTOR TO BECOME SUPERCELLS. AT THIS POINT THE
MODELS PROG THE WARM FRONT TO SET UP JUST TO THE SOUTHWEST OF THE
FORECAST AREA WITH IT LIFTING NORTHEAST TOWARDS A CNK TO EMP LINE BY
FRIDAY EVENING. STORMS SOUTHWEST OF THIS LINE WILL HAVE THE GREATER
LIKELY HOOD OF BECOMING SEVERE. ALTHOUGH ELEVATED STORMS ACROSS
NORTHEAST KS COULD ALSO HAVE HAIL WITH THEM. THERE COULD BE AN
ISOLATED TORNADO THREAT ALONG THE WARM FRONT AS WELL IF A STORM WERE
TO DEVIATE TO THE SOUTHEAST AND RIDE ALONG THE BOUNDARY TAPPING INTO
THE GREATER HELICITY JUST NORTH OF THE BOUNDARY. WITH A CONVERGENCE
IN SOLUTIONS AMONG THE MODELS...HAVE INCREASED POPS INTO THE
CATEGORICAL RANGE ACROSS NORTHERN KS WHERE THE BEST FORCING IS
ANTICIPATED. HAVE LIKELY POPS ACROSS EAST CENTRAL KS THINKING THAT
COVERAGE OF STORMS MAY BE A LITTLE MORE BROKEN IN NATURE.
FRIDAY IS ALSO EXPECTED TO BECOME WINDY AS THE SFC LOW DEEPENS TO
THE WEST. THE INCREASING PRESSURE GRADIENT WILL LIKELY CAUSE EAST
AND SOUTHEAST WINDS TO GUST OVER 30 MPH. LOWS TONIGHT SHOULD NOT
DROP OFF AS MUCH GIVEN INCREASING CLOUD COVER AND A BETTER MIXED
BOUNDARY LAYER. THINK LOWS WILL BE IN THE MID 50S TO AROUND 60 FOR
MOST LOCATIONS. EXPECT A GOOD GRADIENT IN MAX TEMPS FOR TOMORROW
WITH CLOUDS AND EASTERLY WINDS KEEPING HIGHS IN THE LOW 60S OVER FAR
NORTHEAST KS. NEAR AND SOUTHWEST OF THE WARM FRONT...HIGHS SHOULD
WARM INTO THE MID 70S.
WOLTERS
MID TERM (FRIDAY EVENING THROUGH SUNDAY)...
BY FRIDAY EVENING MODELS AGREE ON A SIMILAR POSITION OF THE UPPER
TROUGH AND SURFACE LOW ACROSS CENTRAL INTO NORTHEAST KANSAS. SHOWERS
AND THUNDERSTORMS WILL REMAIN POSSIBLE EARLY FRIDAY EVENING BEFORE
THE SYSTEM QUICKLY EXITS NORTHEAST AND A DRIER AIR MASS FILLS IN ITS
PLACE WITH THE PASSAGE OF A COLD FRONT. BY SATURDAY MORNING THE
FRONTAL BOUNDARY WILL STALL NORTHEAST TO SOUTHWEST OVER SOUTHERN
KANSAS INTO CENTRAL OKLAHOMA. SURFACE RIDGE SETTLING OVER THE CWA
SHOULD KEEP MUCH OF THE AREA STABLE AND CAPPED THROUGHOUT THE
SATURDAY AFTERNOON PERIOD BEFORE ADDITIONAL SHOWERS AND A POSSIBLE
THUNDERSTORM OR TWO DEVELOPS ALONG AND NORTH OF THE BOUNDARY. WHILE
MUCH OF THE INSTABILITY REMAINS JUST SOUTH OF THE CWA...WOULD NOT BE
SURPRISED FOR AN ISOLATED THUNDERSTORM OR TWO. BEST CHANCE FOR
PRECIP ATTM APPEARS TO BE SUNDAY AFTERNOON INTO THE EVENING HOURS AS
ISENTROPIC LIFT INCREASES AND THE WARM FRONT LIFTS NORTHWARD. THE
COVERAGE AND SEVERITY OF ANY THUNDERSTORM STILL REMAINS UNCERTAIN AS
THE MODELS DEPICT VARYING SOLUTIONS ON THE PLACEMENT OF THE WARM
FRONT WITH RESPECT TO OUR AREA. HOWEVER...AMPLE MOISTURE ASSOCIATED
WITH THE BOUNDARY AND THE PRESENCE OF A SHORTWAVE TROUGH PASSING
THROUGH SUNDAY EVENING LEADS TO A DECENT CHANCE FOR ADDITIONAL
PRECIPITATION. TEMPERATURES STILL APPEAR TO BE ON TRACK FOR SATURDAY
AS CLEARER SKIES AND WEAK COLD AIR ADVECTION BEHIND THE SYSTEM SHOULD
HELP RAISE HIGHS INTO THE MIDDLE AND UPPER 60S TOWARDS EAST
CENTRAL KANSAS. CLOUD COVER ON SUNDAY WILL INHIBIT TEMPS TO ONLY
THE LOWER 60S.
EXTENDED TERM (SUNDAY EVENING THROUGH THURSDAY)...
VERY UNSETTLED PATTERN FOR THE EXTENDED TERM WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS EACH DAY. A STALLED SURFACE FRONT SUNDAY
EVENING INTO EARLY NEXT WEEK WILL PROVIDE THE SURFACE CONVERGENCE
ALONG WITH A SERIES OF SHORTWAVES EJECTING FROM THE MAIN TROUGH
OVER THE PACIFIC NORTHWEST INTO THE CENTRAL AND NORTHERN PLAINS.
MODELS ARE STILL HAVING DIFFICULTY WITH RESPECT TO THE TIMING OF
EACH SHORTWAVE TROUGH TO AFFECT THE CWA COMBINED LACK OF STRONG
FORCING FROM ANY FRONTAL BOUNDARIES. REGARDLESS...CONTINUOUS WARM
AIR ADVECTION AND DEWPOINTS RANGING FROM THE UPPER 50S TO MIDDLE
60S SUGGEST CONTINUING CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH THURSDAY. SOUNDING PROFILES SHOW 0-6KM BULK SHEAR VALUES
MARGINAL AROUND 35 KTS WITH MIXED LAYER MUCAPE BETWEEN 1100 AND
1500 J/KG SUGGEST ANY STORMS ABLE TO DEVELOP WILL BE ELEVATED AND
COULD BE STRONG. HEAVY RAIN MAY ALSO BE LIKELY AS BOTH THE GFS AND
ECMWF SHOW PWAT VALUES WELL OVER AN INCH FOR EACH PERIOD IN THE
FORECAST. MAIN CONCERN WILL BE IF THE MAIN FORCING ALOFT WILL
COINCIDE WITH ANY SURFACE FEATURES TO ALLOW THE STRONGER STORMS TO
FORM. BESIDES THE PRECIP POSSIBILITIES...NEAR NORMAL TEMPERATURES
ON MONDAY ARE EXPECTED TO GRADUALLY WARM INTO THE UPPER 70S BY
THURSDAY AS THE THERMAL RIDGE AXIS STRETCHES NORTHWARD OVER THE
CENTRAL PLAINS.
BOWEN
&&
.AVIATION...
GIVEN LATEST TRENDS...HAVE SLOWED ONSET OF MVFR CIGS AND PRECIP
AS WELL AS THE IMPROVING TIMING AROUND 20Z. STILL NOT CONFIDENT
ENOUGH TO INCLUDE ANY TS AROUND 0Z. NOT CERTAING ON TIMING OF
WINDS INCREASING AROUND 12Z...WITH POSSIBLE VCSH HINDERING BETTER
MIXING.
65
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GREAT FALLS MT
1055 PM MDT THU APR 26 2012
UPDATED AVIATION SECTION
.UPDATE...
EXTREME SHORT RANGE MODELS INCLUDING THE HRRR AND RUC HAVE MOVED
INTO TIGHT AGREEMENT WITH LATEST NAM AND GFS RUNS SHOWING A
SIGNIFICANTLY HIGHER AMOUNT OF MOISTURE OVER THE MOUNTAINS OF
SOUTHWEST MONTANA TONIGHT. DUE TO THE SIGNIFICANTLY SHORT
TIME FRAME HAVE MADE THE NONTRADITIONAL DECISION TO UPGRADE THE
WINTER STORM WATCH TO A WARNING THIS EVENING WITH THIS NEW DATA.
DUE TO THE INCREASED CONFIDENCE FOR THE POTENTIAL OF SIGNIFICANT
IMPACTS BEFORE THE NEXT STANDARD FORECAST SUITE UPDATE. THE
WARNING IS IN EFFECT FOR ELEVATIONS ABOVE 6500 FEET...WITH NO
ADVISORY BELOW 6500 FEET DUE TO THE WARMER TEMPERATURES EXPECTED
IN THE VALLEY LOCATIONS OF THE SOUTHWEST TONIGHT. THESE ARE THE
EXPECTED CONDITIONS AT THIS TIME...HOWEVER THERE IS A SLIGHT
POSSIBILITY THAT SNOW ACCUMULATIONS COULD MAKE IT DOWN INTO THE
LOWER ELEVATIONS AND ADDITIONAL HIGHLIGHTS MAY BECOME NECESSARY.
WITH THIS UPDATE...THE IMPACTS FOR LOCATIONS OUTSIDE OF SOUTHWEST
MONTANA LOOK LESS IMPRESSIVE AND DECIDED TO DELAY THE WINTER
WEATHER WATCH UNTIL 1800Z FRIDAY. SUK
&&
.AVIATION...
UPDATED 2355Z.
A STORM SYSTEM WILL KEEP THE WEATHER ACTIVE ACROSS THE AREA THROUGH
THE TAF PERIOD. SCATTERED SHOWERS WILL CONTINUE THIS EVENING AS A
COLD FRONT PASSES THROUGH THE AREA. THUNDERSTORMS COULD AFFECT KLWT
AND KHVR BEFORE 09Z. WESTERLY WINDS WILL INCREASE ACROSS THE AREA
OVERNIGHT AND INTO FRIDAY ALONG WITH AREAS OF PRECIPITATION AND
LOWER CEILINGS... RESULTING IN MVFR CONDITIONS BY LATE IN THE
AFTERNOON. MOUNTAINS WILL BE OBSCURED THROUGH THE TAF PERIOD.
LANGLIEB
&&
.PREV DISCUSSION...
/ISSUED 555 PM MDT THU APR 26 2012/
TODAY THROUGH SATURDAY EVENING...FORECAST STILL ON TRACK FOR PAIR OF
VERY MOIST PACIFIC WEATHER SYSTEMS TO BRING WIDESPREAD AND LONG
DURATION PRECIPITATION ALONG WITH MUCH COOLER TEMPERATURES OVER OUR
REGION THROUGH THE ENTIRE SHORT-TERM FORECAST AREA. CURRENT
SATELLITE IMAGERY SHOWS THE SLIGHTLY WEAKER SYSTEM NOW IN ARIZONA
AND BEGINNING TO LIFT NORTHEASTWARD. MEANWHILE...THE MUCH DEEPER
UPPER LEVEL TROF IS CLOSING IN ON THE WA/OR COAST AND IS EXPECTED TO
MOVE INLAND TONIGHT. ASSOCIATED MOISTURE PLUME WITH THESE SYSTEM
COVERS A BROAD AREA OF THE GREAT BASIN AND NRN ROCKIES WITH
ADDITIONAL MOISTURE EXPECTED TO ACCOMPANY THE STRONGER TROF. AS OF
230 PM LEADING EDGE OF THE MOISTURE IS LOCATED IN OVER OUR FORECAST
AREA WHERE IT HAS BEGUN TO MIX WITH LIFT AND INSTABILITY TO GENERATE
ISOLATED SHOWERS AND A FEW THUNDERSTORMS OVER SOUTHWEST AND CENTRAL
MT. EXPECT THIS ACTIVITY TO BROADEN IN COVERAGE THIS AFTN/EVE BUT
INSTABILITY WILL WEAKEN AFTER SUNSET SO SHOWERS WILL CONTINUE BUT
THUNDERSTORMS SHOULD DISSIPATE. BEST NEWS IN THE OUTLOOK IS THAT
PRIMARY SHORT-TERM FORECAST MODELS ARE IN MUCH BETTER AGREEMENT ON
CONDITIONS FOR TOMORROW AND SATURDAY...CERTAINLY BETTER THAN THE
GLARING DIFFERENCES SEEN THE PAST FEW DAYS. THE TWO WEATHER SYSTEMS
WILL CONTINUE TO TRACK TOWARD EACH OTHER AND EVENTUALLY MERGE OVER
NORTHERN WYOMING LATE FRI...THEN GRADUALLY LIFT INTO FAR SOUTHEAST
MT ON SAT. AS IT DOES SO...ADDITIONAL MOISTURE WILL BE PULLED FROM
THE DAKOTAS OVER THE NRN FLANK OF THE CLOSED LOW PRESSURE
AREA...KEEPING A NEAR CONTINUOUS PERIOD OF RAIN...RAIN/SNOW
MIX...AND SNOW GOING THROUGH SATURDAY. MODELS STILL SHOW SOME
SLIGHT VARIATIONS IN TOTAL PRECIPITATION AND AMOUNTS BUT
GENERALLY EXPECT ONE-HALF TO THREE-QUARTERS OF AN INCH OVER MUCH OF
THE REGION. SNOW WILL DEVELOP OVER THE SOUTHWEST MTNS TONIGHT AND
GRADUALLY SPREAD INTO THE HIGHER ELEVATIONS OF CENTRAL MT FRI PM-SAT
AM. SNOW LEVELS WILL GRADUALLY DROP THROUGH SATURDAY SO A FEW
INCHES OF WET SLUSH ARE POSSIBLE AT ELEVATIONS AROUND 3000 FT WITH
SIGNIFICANTLY HIGHER SNOW AMOUNTS FOR THE CENTRAL MTN RANGES. THUS
CURRENT WINTER WEATHER WATCH FOR ALL BUT OUR NORTHEAST ZONES REMAINS
IN EFFECT AND BEGINS AT MIDNIGHT TONIGHT.
GIVEN THE EXPECTED PRECIP AMOUNTS...RIVERS AND STREAMS WILL CONTINUE
TO RISE. A FEW CREEKS IN GLACIER COUNTY ARE ALREADY NEAR
BANKFULL...SO HAVE ISSUED A SMALL STREAM FLOOD ADVISORY THERE.
FURTHER DETAILS ARE IN THE HYDROLOGY SECTION BELOW.
WARANAUSKAS
SATURDAY NIGHT THROUGH THURSDAY...MODERATE AGREEMENT IN MODEL
GUIDANCE REGARDING THE TIMING AND LOCATION OF THE UPPER LEVEL LOW AS
IT MOVES OUT OF THE REGION. CURRENT FORECAST FAVORS THE GFS SOLUTION
AND KEEPS RESIDUAL MOISTURE AROUND AS THE GFS IS SLOWER TO PUSH THE
SYSTEM NORTHEASTWARD. PRECIPITATION SHOULD BE LIGHT AND REMAIN AS
RAIN...POSSIBLY A RAIN SNOW MIX...IN THE LOWER ELEVATIONS WITH SNOW
IN THE MOUNTAINS. A MORE ZONAL FLOW DEVELOPS EARLY NEXT WEEK AND
WILL PERSIST THROUGH WEDNESDAY. A SHORTWAVE WILL MOVE OVER THE AREA
MONDAY EVENING BRINGING A CHANCE OF PACIFIC MOISTURE...MAINLY TO THE
ROCKY MOUNTAIN FRONT AND SW MONTANA...AND THEN AGAIN ON TUESDAY
EVENING AFFECTING THE SAME AREAS. BY WEDNESDAY AFTERNOON EXPECT
CLEARING AND THE FLOW TO BECOME MORE SOUTHWESTERLY. TEMPERATURES
WILL START OFF A LITTLE COOL ON SUNDAY AND APPROACH SEASONAL
AVERAGES THE REMAINDER OF THE PERIOD. MERCER
&&
.PRELIMINARY POINT TEMPS/POPS...
GTF 39 50 33 47 / 80 60 70 70
CTB 34 48 31 49 / 90 60 70 70
HLN 36 48 32 49 / 90 50 60 60
BZN 31 46 23 46 / 90 80 60 60
WEY 27 35 18 37 / 100 80 70 60
DLN 30 43 24 46 / 100 70 50 50
HVR 38 51 33 45 / 80 70 80 60
LWT 35 47 30 41 / 90 70 70 70
&&
.TFX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY
AFTERNOON BROADWATER...CASCADE...CENTRAL AND SOUTHERN LEWIS AND
CLARK...CHOUTEAU...EASTERN GLACIER...EASTERN PONDERA...EASTERN
TETON...FERGUS...JEFFERSON...JUDITH BASIN...MEAGHER...NORTHERN
ROCKY MOUNTAIN FRONT...SOUTHERN ROCKY MOUNTAIN FRONT.
WINTER STORM WARNING UNTIL NOON MDT FRIDAY FOR ELEVATIONS ABOVE
6500 FEET FOR BEAVERHEAD...GALLATIN...MADISON.
SMALL STREAM FLOOD ADVISORY FOR GLACIER COUNTY UNTIL NOON SATURDAY.
&&
$$
SHORT TERM...SUK
LONG TERM...MERCER
AVIATION...LANGLIEB
WEATHER.GOV/GREATFALLS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1135 PM CDT THU APR 26 2012
.AVIATION...06Z TAFS FOR KOMA...KLNK AND KOFK. SPOTTY SHOWERS OR
SPRINKLES MOVING THROUGH THE KOMA/KOFK CURRENTLY AND WILL LIKELY
BE OVER BY ABOUT 08Z. THEN THERE WILL BE A SEVERAL HOUR BREAK
BEFORE PRECIPITATION MOVES BACK IN LATER ON MONDAY MORNING. THERE
WILL ALSO BE SOME LOW LEVEL WIND SHEAR AT ALL TAF SITES THROUGH
LATER THIS MORNING AS WELL...WITH EAST SOUTHEAST SURFACE WINDS
INCREASING TO 18 TO 22 KTS SUSTAINED WITH HIGHER GUSTS. RAIN
MOVES BACK INTO THE KOFK BY 15Z...KLNK BY 17Z AND KOMA BY 18Z WITH
MVFR CEILINGS DEVELOPING. THERE COULD BE SOME THUNDERSTORMS ALONG
THE NE/KS BORDER REGION LATER SATURDAY AFTERNOON AND EVENING BUT
SHOULD REMAIN SOUTH OF THE KLNK TAF SITE. AS LOW PRESSURE MOVES TO
NEAR KSTJ LATE IN THE TAF PERIOD...WINDS WILL LIKELY SWITCH TO THE
NORTH...BUT DID NOT ADD IN ADDITIONAL GROUPINGS THAT FAR OUT.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 915 PM CDT THU APR 26 2012/
DISCUSSION...
FIRST BAND OF LIGHT SHOWERS OR SPRINKLES IS MOVING INTO WESTERN
PORTIONS OF THE FORECAST AREA. RAIN IS REACHING THE GROUND IN
NORTHEAST NEBRASKA WHERE DBZ RETURNS HAVE BEEN SLIGHTLY HEAVIER.
STILL SOME DRY AIR AT THE SURFACE WHICH HAS TO BE OVERCOME FIRST.
FURTHER SOUTH OF COLUMBUS TOWARD BEATRICE...PROBABLY NOTHING MORE
THAN A FEW SPRINKLES THERE. THIS BAND WILL CONTINUE TO PUSH
EASTWARD THIS EVENING...AND COULD LIKELY STILL SEE SOME SPRINKLES
MOVE TOWARD THE REMAINDER OF EASTERN NEBRASKA TOWARD THE MISSOURI
RIVER.
BELIEVE THERE WILL PROBABLY BE A BREAK IN THE PRECIPITATION BEHIND
THIS INITIAL BAND. REGIONAL RADAR MOSAIC SHOWS A LOT OF PRECIP
FREE AREAS ACROSS CENTRAL KANSAS AND CENTRAL KANSAS...WHICH BOTH
THE 21Z SREF AND 00Z NAM PICKED UP ON. ADJUSTED POPS OVERNIGHT TO
ACCOUNT FOR THAT...ALTHOUGH STILL LEFT IN A SLIGHT CHANCE FOR
MAINLY A SPRINKLE. THE MAIN AREA OF STEADIER RAIN/SHOWERS DOES
SPREAD ACROSS THE FORECAST AREA FRIDAY MORNING...BUT PERHAPS JUST
A COUPLE HOURS SLOWER THAN PREVIOUSLY THOUGHT.
DEWALD
PREV DISCUSSION... /ISSUED 348 PM CDT THU APR 26 2012/
SHORT TERM...TONIGHT.
THE MAIN FORECAST CONCERN TONIGHT WILL BE THE CHANCE FOR SHOWERS.
THE CLOUDS WILL CONTINUE TO THICKEN THIS EVENING AS THE FIRST
AREA OF LIFT MOVES ACROSS THE FORECAST AREA. THE SHORT TERM MODELS
DO NOT HAVE A REAL GOOD HANDLE ON THE PRECIP FROM WESTERN NEBRASKA
INTO KANSAS...ALTHOUGH MOST OF THIS IS LIGHT. THE GFS WAS DOING
THE BEST AND THE 15Z SREF BETTER THAN THE 09Z SREF. THE HRRR HAS
SOME PRECIP UP TO THE CWA...THEN DISSIPATES IT THIS EVENING WITH
SOME INCREASE IN THE NORTHEAST PART OF THE FORECAST AREA AFTER
06Z.DUE TO THE DRY AIR IN PLACE...THERE MAY BE A FEW SHOWERS OR
SPRINKLES...WITH THE BEST CHANCE FOR SOME MINOR PRECIP
ACCUMULATIONS IN THE WEST OF WAYNE AND LINCOLN AND SPRINKLES
FARTHER EAST. DID NOT MENTION THUNDER AS BOTH THE NAM/GFS TENDED
TO KEEP THE BETTER INSTABILITY IN THE WESTERN PART OF THE CWA OR
TO THE WEST TONIGHT. SOUTHEAST WINDS LOOK TO INCREASE INTO THE 15
TO 30 MPH RANGE OVERNIGHT.
ZAPOTOCNY
LONG TERM...SATURDAY THROUGH THURSDAY.
PRECIPITATION CHANCES WILL PROVIDE THE MAIN FORECAST CHALLENGES
THROUGH THE EARLY PART OF THIS PERIOD.
500 MB CHART FROM THIS MORNING SHOWED A STRONG AND COMPACT CLOSED
LOW JUST WEST OF SAN DIEGO. THIS FEATURE HAD 12 HOUR HEIGHT FALLS
OF AROUND 170 METERS. IT WILL CONTINUE TO TRACK QUICKLY NORTHEAST
AND SHOULD BE OVER THE EASTERN COLORADO/NORTHWEST KANSAS BORDER
AREA BY 12Z FRIDAY. AS THIS FEATURE LIFTS OUT INTO THE CENTRAL
PLAINS FRIDAY...EXPECT FAIRLY WIDESPREAD PRECIPITATION TO OCCUR.
LOW LEVELS WILL BE SLOW TO SATURATE...WITH MAIN 850 MB MOISTURE
AND INSTABILITY AXIS GENERALLY REMAINING WEST AND SOUTH OF THE
FORECAST AREA. 12Z GFS SHOWED 850 DEWPOINTS REACHING 10-12
DEGREES CELCIUS IN PARTS OF SOUTHEAST NEBRASKA DURING THE DAY.
CAN NOT RULE OUT A FEW STORMS INTO THAT AREA...BUT MAIN SEVERE
THREAT SHOULD STAY TO OUR SOUTH FRIDAY. TEMPERATURES WILL BE COOL
WITH EASTERLY WINDS...CLOUDS AND PRECIPITATION. GENERALLY STAYED
BELOW MOS GUIDANCE FOR HIGHS FRIDAY.
KEPT FAIRLY HIGH RAIN CHANCES FRIDAY NIGHT AND SOME THUNDERSTORMS
STILL SEEM POSSIBLE IN THE EVENING...ESPECIALLY OVER SOUTHEAST
NEBRASKA AND SOUTHWEST IOWA. FAIRLY STRONG DRYING TAKES PLACE
BEHIND THE MAIN SHORTWAVE TROUGH BY LATE FRIDAY NIGHT SO EXPECT
SATURDAY TO BE MOSTLY DRY. THE 12Z ECMWF AND 12Z GFS MODEL SOLUTIONS
START TO DIVERGE BY SATURDAY NIGHT INTO SUNDAY. GFS IS MORE
AGGRESSIVE WITH PRECIPITATION SPREADING BACK INTO THE AREA FROM
THE SOUTH. GENERALLY FELT THE ECMWF WAS HANDLING THE PATTERN
BETTER THAN THE GFS...BUT COULD NOT RULE OUT GFS SOLUTION SO
BLENDED SOME OF THAT THINKING INTO GRIDS. A DIFFERENT CLOSED
LOW...ASSOCIATED WITH THE TROUGH CURRENTLY OFF THE PACIFIC
NORTHWEST...WILL MOVE INTO NORTHERN WYOMING OR SOUTHERN MONTANA BY
00Z SATURDAY. THIS SHOULD TRACK EAST TOWARD THE WESTERN DAKOTAS
THROUGH SATURDAY EVENING AND THEN LIFT NORTH THROUGH SUNDAY NIGHT.
MAIN AFFECTS FROM THAT SHOULD STAY TO OUR WEST OR SOUTH.
A WEAK TROUGH REMAINS OVER THE ROCKIES THROUGH MID WEEK...WITH
SEVERAL RIPPLES IN THE FLOW MOVING OUT ACROSS OUR AREA. THE TIMING
DIFFERENCES PERSIST THROUGH DAY 7.
MILLER
AVIATION...
18Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE FORECAST THROUGH 27/15Z. FIRST PIECE OF ENERGY
WILL LIFT ACROSS THE TAF SITES THIS AFTERNOON. MID LEVEL CLOUDS
WILL BE ON THE INCREASE MOSTLY AT FL100...BUT ALSO SOME SCT-BKN AT
FL050. DRY AIR SHOULD LIMIT WIDESPREAD PRECIPITATION. THERE MAY BE
A FEW SPRINKLES OR SHOWERS...HOWEVER DUE TO SPOTTY NATURE HAVE NOT
INCLUDED. THE STRONGER PIECE OF ENERGY WILL MOVE ACROSS THE AREA
FRIDAY. DEEP MOISTURE WILL BE AVAILABLE WITH STRONGER LIFT AND
MORE WIDESPREAD PRECIPITATION ALONG WITH LOWER MVFR CIGS POSSIBLE.
NORTHEAST WINDS WILL BECOME EAST AT 10 TO 15KTS WITH SOME GUSTS 20
TO 25KTS. TONIGHT AFTER 06Z...EAST TO SOUTHEAST WINDS WILL
INCREASE TO 15 TO 25KTS WITH GUSTS 25 TO 30KTS. MENTIONED LOW
LEVEL WIND SHEAR AT KOMA AND KLNK AFT 09Z WITH 2K WINDS INCREASING
TO 45 TO 55KTS.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1139 PM CDT THU APR 26 2012
.AVIATION...
LOW STRATUS HAS DEVELOPED AT KCDS BUT IS NOT EXPECTED TO PERSIST
FOR MORE THAN A FEW HOURS. OTHERWISE...SOUTHEASTERLY WINDS WILL
REMAIN BREEZY THROUGH THE EARLY MORNING HOURS. A COLD FRONT WILL
QUICKLY MOVE THROUGH THE AREA BEFORE DAYBREAK SHIFTING WINDS TO
THE WEST AND INCREASING SPEEDS. THESE WINDS WILL DECREASE NEAR
SUNSET ON FRIDAY.
&&
.PREV DISCUSSION... /ISSUED 819 PM CDT THU APR 26 2012/
UPDATE...
REMAINING OUTFLOW BOUNDARIES FROM PREVIOUS CONVECTION WAS
UNSUCCESSFUL IN INITIATING STORMS. LIFT FROM THE TROUGH HAS MOVED
EAST AND NORTH OF THE AREA. REMAINING LIFT FROM THE TROUGH IS
EXPECTED TO SKIRT NORTH OF THE AREA LATER TONIGHT INTO EARLY
FRIDAY. HAVE ALSO UPDATED THE REST OF THE FORECAST TO MAINLY
REMOVE POPS.
PREV DISCUSSION... /ISSUED 315 PM CDT THU APR 26 2012/
SHORT TERM...
MOIST EASTERLY FLOW THIS AFTERNOON WILL TURN 180 DEGREES BY TOMORROW
MORNING AND DRY OUT BEHIND A DRYLINE AND WEAK PACIFIC COLD FRONT.
UNTIL THEN...THE FORECAST CHALLENGE REMAINS FOCUSED ON TSTRM
OPPORTUNITIES LATE THIS AFTN AND EVENING WITHIN A FAVORABLY MOIST
AND DESTABILIZING ATMOSPHERE. AS OF 20Z...THIS WINDOW DOES APPEAR TO
BE OPENING FURTHER AS THE LEADING EDGE OF HEIGHT FALLS IS NOW
ADVANCING INTO ERN NM WELL IN ADVANCE OF A TIGHTLY-WOUND UPPER LOW
IN CENTRAL AZ. VISIBLE SATELLITE CONFIRMS THIS TREND AS BOUNDARY
LAYER CUMULUS AND MID-LEVEL CLOUDS HAVE QUICKLY THICKENED BETWEEN
CLINES CORNERS AND CLOVIS. SURFACE OBSERVATIONS CLEARLY REVEAL THE
DRYLINE WILL NOT MIX AS FAR EAST AS 12Z MODELS AND RECENT RUNS OF
THE HRRR SUGGESTED...LARGELY DUE TO A SLOWER UPPER TROUGH AND ITS
SUBSEQUENT DELAY WITH WESTERLY SURFACE FLOW. SURFACE FRONT FROM
EARLIER THIS MORNING HAS ESSENTIALLY DIFFUSED...ALTHOUGH MODELS
INDICATE SOME SEMBLANCE OF THIS A FEW THOUSAND FEET ALOFT LIFTING
SLOWLY NORTH AS A WARM FRONT. LATEST RUC APPEARS THE MOST CREDIBLE
WITH THE DRYLINE SHARPENING UP NEAR HWY 385 BEFORE SUNSET INSTEAD OF
I27 AS PREVIOUSLY THOUGHT. EXODUS OF A SUBTROPICAL CIRRUS SHIELD
ACROSS THE NWRN HALF OF THE CWA HAS ALREADY PUSHED CIN TO NEAR ZERO
IN PLACES...WITH HIGH-BASED CUMULONIMBUS FOUND DEVELOPING FROM NEAR
TCC NORTHEAST TO NEAR CHANNING...AND ALSO SOUTHWARD INTO OUR WRN
COUNTIES. CAPE INCREASES MARKEDLY FARTHER EAST WHERE MOISTURE IS
SIGNIFICANTLY BETTER...SO TEND TO BELIEVE A LARGE HAIL THREAT WILL
DOMINATE AS STORMS FAVOR DISCRETE MODES...LIKELY SUPERCELLULAR
GIVEN FAVORABLE BOUNDARY-ORIENTED 0-6KM SHEAR VECTORS. RECENT SWOMCD
FULLY CONFIRMS THREAT FOR SVR CONVECTION.
AS EARLIER AFD MENTIONED...THE GREATEST COVERAGE OF CONVECTION
SHOULD TAKE AIM NORTH OF THE CWA GENERALLY ALONG AND NORTH OF THE
AXIS OF A CYCLONICALLY-CURVED UPPER JET STREAK. WILL HOWEVER
MAINTAIN ISO TSTRM MENTION MAINLY OVER OUR NRN COUNTIES THROUGH
MIDNIGHT AS THIS REGION WILL LIE NEAR THE EDGE OF DEEP ASCENT.
DRYLINE SHOULD BE OVERTAKEN BY A PACIFIC COLD FRONT BEFORE SUNRISE
FRI AT WHICH POINT BREEZY WESTERLY WINDS WILL DEVELOP...WITH DEEPER
MIXING BY MID-MORNING LIKELY SECURING SUSTAINED WLY WINDS OF 20-25
MPH. DEPARTURE OF THE UPPER TROUGH FROM SERN CO INTO NEBRASKA BY 18Z
IMPLIES A DIMINISHED GRADIENT FLOW LOCALLY...SO DESPITE MORE
UNSEASONABLE WARMTH...FIRE WEATHER CONCERNS DO NOT APPEAR ROBUST
ENOUGH FOR A FIRE WEATHER WATCH AS WINDS WILL BE DIMINISHING
THROUGHOUT THE DAY.
LONG TERM...
ONLY MINOR ADJUSTMENTS MADE TO THE LONG TERM FORECAST TODAY...WITH A
PERIOD OF UNSETTLED WEATHER POSSIBLE FROM THE LATTER HALF OF THE
WEEKEND INTO AT LEAST EARLY NEXT WEEK.
THE MID-LEVEL PATTERN THROUGH MUCH OF THE EXTENDED WILL BE DOMINATED
BY SOME SEMBLANCE OF WESTERN TROUGHING...WHICH WILL KEEP WEST TEXAS
UNDER VARIATIONS OF SOUTHWEST FLOW ALOFT. EARLY ON...A SHORTWAVE
TROUGH WILL QUICKLY LIFT NORTHWARD ACROSS THE UPPER MIDWEST AS A
CLOSED LOW MIGRATES FROM THE NORTHERN ROCKIES INTO THE NORTHERN HIGH
PLAINS FROM FRIDAY INTO SATURDAY. THIS SHOULD HELP FORCE A COLD
FRONT SOUTHWARD INTO THE SOUTH PLAINS ON SATURDAY BEFORE IT STALLS
OUT LATER IN THE DAY. THE INITIAL FROPA STILL APPEARS TO BE A DRY
ONE...WITH THE BETTER LOW-LEVEL MOISTURE SHUNTED SOUTH AND EAST OF
THE AREA. HOWEVER...BY SATURDAY NIGHT...A SOUTHERLY LLJ WILL
INCREASE AND BEGIN TO DRAW BETTER AMOUNTS OF MOISTURE UP AND OVER
THE COOL DOME IN PLACE...AND THIS WAA REGIME WILL RESULT IMPROVING
CHANCES OF ELEVATED SHOWERS/STORMS. LATEST INDICATIONS ARE THAT
THE FRONT WILL GRADUALLY RETREAT NORTHWARD SATURDAY NIGHT AND
EARLY SUNDAY...WITH PERHAPS A MCS DEVELOPING TO ITS NORTH. RIGHT
NOW...IT APPEARS THE MOST FAVORED REGION FOR A POTENTIAL MCS WOULD
BE DISPLACED TO THE NORTH...ACROSS THE PANHANDLES...THOUGH THIS
COULD CHANGE DEPENDING ON THE EXACT POSITION OF THE FRONT. FOR
NOW...HAVE CURTAILED POPS TO FAVOR THE NORTHERN AND NORTHEASTERN
SECTIONS SATURDAY NIGHT AND EARLY SUNDAY...WITH MORE DEVELOPMENT
POSSIBLE ALONG THE DRYLINE /LIKELY LOCATED NEAR THE TX/NM LINE/ BY
LATER IN THE DAY SUNDAY. THE 12Z NAM DOES ATTEMPT TO FORCE THE
FRONT BACK SOUTHWARD LATER SUNDAY...LIKELY AS A RESULT OF A
REINFORCED COLD POOL FROM THE EARLY DAY MCS...BUT THESE DETAILS
REMAIN TOO ELUSIVE/UNCERTAIN TO FOLLOW ATTM. TEMPERATURES DO ALSO
REMAIN A LITTLE TRICKY THIS WEEKEND GIVEN SOME UNCERTAINTY WITH
THE FRONTAL POSITION...BUT HAVE TENDED TOWARD A COMPROMISE FOR
NOW...WITH HIGHS GENERALLY IN THE 70S TO LOWER 80S.
EARLY NEXT WEEK WILL FEATURE A DRYLINE ROAMING THE AREA UNDERNEATH
SOUTHWEST FLOW ALOFT AND THIS PATTERN WILL KEEP AT LEAST LOW THUNDER
CHANCES IN THE FORECAST...FAVORING THE AFTERNOON AND EVENING HOURS.
TOWARD THE MIDDLE OF NEXT WEEK THE MID-LEVEL FLOW MAY TURN MORE
WESTERLY /AND MAYBE EVEN WEAKLY ANTICYCLONIC/ AND THIS WOULD TEND TO
PUSH THE BETTER MOISTURE EASTWARD AND MAKE LOW THUNDER CHANCES EVEN
LESS CERTAIN. THUS...HAVE MAINTAINED A DRY FORECAST FROM WEDNESDAY
ONWARD FOR NOW. TEMPERATURES FOR NEXT WEEK WILL AGAIN BE ON THE WARM
SIDE OF AVERAGE...WITH HIGHS GENERALLY IN THE 80S.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 52 82 47 75 49 / 10 0 10 10 20
TULIA 55 85 49 75 52 / 10 0 10 10 30
PLAINVIEW 56 85 51 76 55 / 10 0 10 10 20
LEVELLAND 54 86 53 80 57 / 10 0 10 10 20
LUBBOCK 60 88 55 80 58 / 10 0 10 10 20
DENVER CITY 54 86 53 83 55 / 10 0 0 10 20
BROWNFIELD 55 88 54 82 60 / 10 0 10 10 20
CHILDRESS 63 93 56 80 59 / 10 10 10 10 30
SPUR 61 91 56 81 61 / 10 0 10 10 20
ASPERMONT 67 96 59 84 61 / 10 0 10 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE LOW
WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE AREA.
DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST WISCONSIN...THUS
AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST TO SATURATE. OF
CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT. SOUNDINGS FROM BOTH
THE GFS AND NAM INDICATE THE POTENTIAL FOR THE COLUMN TO COOL
ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS NORTH OF
INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH ICE WILL BE
PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS INDICATE TO
BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH SURFACE
TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY SNOW THAT
DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE RAIN
COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC RAIN
CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR OUT AND
THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE ON THE
UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY THROUGH
THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO THE
REGION.
&&
.AVIATION...THROUGH 06Z SATURDAY
1143 PM CDT THU APR 26 2012
A GRADUAL THICKENING AND LOWERING OF THE CLOUDS IS EXPECTED TO
OCCUR THROUGH FRIDAY AS A DEVELOPING STORM SYSTEM OVER COLORADO
STARTS TO ADVANCE TOWARD THE AREA. LOOK FOR VFR CONDITIONS TO
PREVAIL THROUGH FRIDAY WITH CEILINGS REMAINING AT OR ABOVE 10
THOUSAND FEET. THE GRADIENT BETWEEN THE APPROACHING AREA OF LOW
PRESSURE AND DEPARTING SURFACE HIGH WILL CREATE GUSTS OF 20 TO 25
KNOTS OUT OF THE SOUTHEAST AT BOTH SITES FROM MID TO LATE MORNING
THROUGH THE AFTERNOON. AFTER 00Z SATURDAY...A BAND OF
FRONTOGENESIS IN THE 850-500 MB LAYER WILL SET UP ACROSS THE AREA.
THE FORCING FROM THIS WILL BE AIDED BY 2 TO 5 UBAR/S OF UP GLIDE
ON THE 300K ISENTROPIC SURFACE. THIS FORCING IS EXPECTED TO BE
ENOUGH TO ALLOW SATURATION TO OCCUR AND FOR LIGHT RAIN TO DEVELOP.
INITIALLY NOT EXPECTING THE RAIN TO REDUCE THE VISIBILITY BUT THIS
WILL BE POSSIBLE AFTER 06Z SATURDAY AS WILL MVFR CEILINGS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CDT FRI APR 27 2012
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ032-033-041-
053>055-061.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...04
AREA FORECAST DISCUSSION
NWS DENVER CO
442 AM MDT FRI APR 27 2012
.SHORT TERM...700-500MB LOW CENTERED JUST SOUTH OF LIMON/SOUTHERN
LINCOLN COUNTY/ AT THIS HOUR ACCORDING TO RUC AND RADAR/SATELLITE
DATA. STRONG ISENTROPIC LIFT ON NORTH-EAST SIDE OF UPPER LOW WITH
A CONVEYOR BELT OF MOISTURE WRAPPING AROUND THE LOW CONTINUES TO
GENERATE NUMEROUS SHOWERS AND SCATTERED T-STORMS OVER MUCH OF
NORTHEAST COLORADO. SMALL STREAM FLOOD ADVISORY WAS ISSUED EARLIER
THIS MORNING FOR MUCH OF LINCOLN COUNTY WITH TRAINING STORMS
DROPPED 2-3 INCHES OF RAIN IN MATTER OF A FEW HOURS ACCORDING TO
RADAR. IN ADDITION HAVE WITNESSED NEW SHOWER/T-STORM DEVELOPMENT
IN THE PAST HOUR ALONG THE FRONT RANGE DUE IN LARGE PART TO A
CONVERGENCE OF DRIER NORTHWESTERLY FLOW OFF THE FRONT RANGE AND
MOIST EASTERLY FLOW ROUNDING THE TOP OF UPPER LOW. ONLY A MATTER
OF TIME FOR THIS NEW BATCH OF SHOWERS TO EITHER MOVE EAST OF THE
AREA OR JUST DISSIPATE WITH THE UPPER LOW CONTINUING TO MOVE EAST-
NORTHEAST AWAY FROM THE FRONT RANGE. HIGH PLAINS AIRMASS HAS
PRETTY BEEN WORK OVER WITH ONLY MARGINAL INSTABILITY SUSTAINING
CONVECTION. WITH THE UPPER LOW EXITING THE STATE MID TO LATE
MORNING...SO SHOULD MOST OF THIS PRECIPITATION...EXCEPT PERHAPS
IN THE FAR NORTHEAST CORNER OF THE STATE AND UP OF THE UPPER
RIDGES ALONG THE CONTINENTAL DIVIDE. CONSEQUENTLY...THE SEVERE
T-STORM WATCH FOR MUCH OF NERN COLORADO HAS BEEN ALLOWED TO
EXPIRE.
ATTENTION TURNS TO THE POSSIBILITY OF STRONG WINDS ON THE PLAINS
AND IN THE FRONT RANGE FOOTHILLS LATER THIS MORNING AND AFTERNOON
AS THE AREA COMES UNDER THE INFLUENCE OF MODERATE SUBSIDENCE AND
INCREASING POST-TROUGH NORTHWESTERLY FLOW ALOFT. CROSS SECTIONS
INDICATE CROSS MTN WIND SPEEDS OVER HIGHER ELEVATIONS OF THE FRONT
RANGE IN THE 40-50KT RANGE MID--MORNING THROUGH MID-AFTERNOON. ON
THE PLAINS...WINDS NOT AS STRONG...BUT NORTHEAST CORNER AND UP
ALONG THE WYOMING BORDER MODELS INDICATE WIND GUSTS IN THE
30-40KT RANGE DURING THE SAME PERIOD. PRESSURE GRADIENT IS
EXPECTED TO QUICKLY RELAX LATE THIS AFTERNOON RESULTING IN A RAPID
DROP OFF IN WIND SPEEDS BEFORE DARK. OTHERWISE AFTER THE SHOWERS
THIS MORNING...SHOULD SEE PLENTY OF SUNSHINE AND MUCH LOWER
HUMIDITY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE. TONIGHT...AREAS
WEST OF THE CONTINENTAL DIVIDE EXPECTED TO SEE A GRADUAL INCREASE
IN MID-LEVEL CLOUD COVER IN RESPONSE TO THE NEXT UPPER AIR TROUGH
TO DROPPING IN FROM THE NORTHWEST.
.LONG TERM...THE UPPER LOW WILL REMAIN ANCHORED OVER WYOMING ON
SATURDAY BEFORE LIFTING INTO THE DAKOTAS ON SUNDAY. THIS WILL
LEAVE COLORADO IN A RELATIVELY DRY WESTERLY FLOW THROUGH THE
WEEKEND. HOWEVER THERE WILL BE SOME RETURN LOW LEVEL MOISTURE IN
DEVELOPING SOUTHEAST LOW LVL FLOW ALONG WITH A JET SEGMENT AND
WEAK WAVE LIFTING THROUGH SOUTHEAST COLORADO LATE SATURDAY NIGHT
AND SUNDAY. THIS WILL RESULT IN SOME SCATTERED SHOWER ACTIVITY
ACROSS THE EASTERN PLAINS. MONDAY LOOKS TO BE RATHER DRY EXCEPT
MAYBE A SLIGHT CHANCE OF LATE DAY SHOWERS. THE NEXT WAVE WILL
BRING A BIT OF AN INCREASE IN SHOWERS FOR LATE TUESDAY AND
WEDNESDAY BUT OVERALL MOISTURE AND INSTABILITY IS MARGINAL AND
WILL KEEP POPS IN THE SLIGHT CHANCE RANGE. TEMPERATURES WILL
GRADUALLY WARM TO ABOVE SEASONAL HIGHS BY EARLY NEXT WEEK.
&&
.AVIATION...LIFR CEILINGS AND VISIBILITY AT PRESENT TIME AT
DENVER AREA AIRPORTS EXPECTED TO RAPIDLY IMPROVE OVER THE NEXT 1-2
HOURS AS DRIER AIR MOVES DOWN FROM THE FRONT RANGE ON NORTHWEST
WINDS. CIGS AND VSBYS AT BJC SHOULD GO VFR BY 12Z AND NOT LONG
AFTER THAT AT DIA. AFTER THAT TIME...LOOK FOR NORTHWEST WINDS TO
INCREASE DURING THE LATE MORNING HOURS WITH POSSIBLE GUSTS IN THE
20-25KT RANGE BY MIDDAY..POSSIBLY STRONG NEAR THE FOOTHILLS. BY
LATE AFTERNOON...A WEAKENING OF THE PRESSURE GRADIENT WITH THE
UPPER LOW WELL EAST OF COLORADO...EXPECT TO SEE SFC WINDS TURN
NORTH-NORTHEAST FOR A TIME EARLY THIS EVENING BEFORE ASSUMING A
TYPICAL DRAINAGE WIND PATTERN AFTER 03Z. ALL THIS UNDER CLEAR TO
MOSTLY CLEAR SKIES.
&&
.HYDROLOGY...PRECIPITATION NEARLY OVER THE FRONT RANGE FOOTHILLS
WITH DRIER DOWNSLOPE FLOW SETTING UP FOR THE REMAINDER OF THE DAY.
COULD STILL SEE A BRIEF SHOWER MOVE OFF THE CONTINENTAL DIVIDE AND
OVER THE FOOTHILLS EARLY THIS MORNING AND DEPOSIT A FEW HUNDREDTHS
OF AN INCH OF RAIN. OTHERWISE NO ADDITIONAL PRECIPITATION
ANTICIPATED FOR THE BURN AREAS ALONG THE FRONT RANGE WITH THIS
STORM SYSTEM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BAKER
LONG TERM....ENTREKIN
AVIATION...BAKER
AREA FORECAST DISCUSSION
NWS MIAMI FL
1021 AM EDT FRI APR 27 2012
.UPDATE...NO MAJOR CHANGES PLANNED FOR MORNING UPDATES WITH
CURRENT FCST SEEMING TO BE ON TRACK BASED ON CURRENT TRENDS. DEEP
TROPICAL MOISTURE NOT FAR TO OUR SE BUT THIS SHOULD REMAIN
OFFSHORE FOR MOST OF TODAY BEFORE BEING PULLED NORTH OVER THE
WEEKEND. THE 12Z MFL SOUNDING SHOWS VERY DRY CONTINUES ABOVE 5K
BUT THE LOWER LAYERS HAVE MOISTENED WITH PWAT INCREASING TO AN
INCH. THIS MAY BE ENOUGH TO SUPPORT A FEW SHRA LATE THIS AFTERNOON
AND IF FACT THE RAPID REFRESH HAS BEEN CONSISTENT THIS MORNING AND
SHOWING A FEW SHRA DEVELOPING OVER THE FAR SOUTH AND ALONG THE W
CST SEA BREEZE ACROSS INLAND COLLIER COUNTY. SO THAT IS THE ONLY
PLANNED CHANGE TO UP THE POPS TO SLIGHT CHANCE FOR THAT AREA INTO
THE EVENING.
KOB
&&
.PREV DISCUSSION... /ISSUED 647 AM EDT FRI APR 27 2012/
AVIATION...12Z ISSUANCE...PREVAILING VFR THROUGH THIS EVENING.
AS A SURFACE HIGH PRESSURE SYSTEM MOVES NORTHEAST AND MOISTURE
BEGINS TO INCREASE IN RESPONSE TO A DEVELOPING TROUGH OVER THE
CARIBBEAN, CLOUDINESS WILL GRADUALLY LOWER AND THICKEN THROUGH
THE PERIOD, ESPECIALLY AFTER 22Z. VCSH WILL ALSO BECOME POSSIBLE
AFTER 06Z, PARTICULARLY ALONG AND NEAR THE SOUTHEAST FLORIDA
COAST. WINDS WILL REMAIN EAST AROUND 10 KNOTS WITH SOME HIGHER
GUSTS, ESPECIALLY AFTER 18Z.
PREV DISCUSSION... /ISSUED 415 AM EDT FRI APR 27 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
.ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 74 82 72 / - 10 40 30
FORT LAUDERDALE 81 73 83 71 / - 30 50 50
MIAMI 82 73 82 70 / 10 40 50 50
NAPLES 86 67 87 69 / - 10 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
647 AM EDT FRI APR 27 2012
.AVIATION...12Z ISSUANCE...PREVAILING VFR THROUGH THIS EVENING.
AS A SURFACE HIGH PRESSURE SYSTEM MOVES NORTHEAST AND MOISTURE
BEGINS TO INCREASE IN RESPONSE TO A DEVELOPING TROUGH OVER THE
CARIBBEAN, CLOUDINESS WILL GRADUALLY LOWER AND THICKEN THROUGH
THE PERIOD, ESPECIALLY AFTER 22Z. VCSH WILL ALSO BECOME POSSIBLE
AFTER 06Z, PARTICULARLY ALONG AND NEAR THE SOUTHEAST FLORIDA
COAST. WINDS WILL REMAIN EAST AROUND 10 KNOTS WITH SOME HIGHER
GUSTS, ESPECIALLY AFTER 18Z.
&&
.PREV DISCUSSION... /ISSUED 415 AM EDT FRI APR 27 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
..ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 74 82 72 / - 10 40 30
FORT LAUDERDALE 81 73 83 71 / - 30 50 50
MIAMI 82 73 82 70 / 10 40 50 50
NAPLES 86 67 87 69 / - 10 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AVIATION...14/MJB
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
745 AM EDT FRI APR 27 2012
.SHORT TERM /TODAY THROUGH SATURDAY/...
WEAK NORTHWESTERLY FLOW ALOFT HELPED A WEAK SURFACE COLD FRONT
MOVE TO THE NORTHERN DOORSTEP OF GEORGIA...AND STALL THERE. THIS
WILL SERVE AS A FOCUS FOR AFTERNOON CONVECTION THIS AFTERNOON...
ALTHOUGH THERE IS GREAT MODEL DISPARITY REGARDING THE AREAL
COVERAGE AND ACCUMULATION. NAM AND SREF ARE FAR MORE AGGRESSIVE
WITH LATE AFTERNOON THUNDERSTORMS FOR NORTH GEORGIA...BUT
ECMWF...GFS AND HRRR HAVE FAR LESS COVERAGE AND LIGHTER
ACCUMULATIONS. WILL SIDE WITH THE LESS AGGRESSIVE SOLUTIONS FOR
NOW...BUT THIS WILL NEED TO BE WATCHED. EXPECTING WIDESPREAD
MORNING STRATUS WHICH WILL INHIBIT HEATING...SO LATER CONVECTIVE
INITIATION SEEMS REASONABLE. CENTRAL GEORGIA LOOKS LIKE IT WILL
ESCAPE THE PRECIP CHANCES FOR THE SHORT-TERM. MOS TEMPS LOOK
GOOD...SO WILL NOT STRAY FROM GUIDANCE.
27
.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
EXTENDED BEGINS WITH RIDGING BUILDING IN ALOFT AND SURFACE HIGH
PRESSURE OVER THE WESTERN ATLANTIC RIDGING INTO THE SOUTHEAST. THE
MAIN FLOW...ALONG WITH WEAK EMBEDDED IMPULSES...REMAINS JUST TO OUR
NORTH ROUNDING THE TOP OF THE RIDGE. WITH INCREASING THICKNESSES
AND MOISTURE...THE GFS REALLY INCREASES TEMPS ON SUNDAY...
FORECASTING RECORD OR NEAR-RECORD HIGHS IN THE UPPER 80S AND LOWER
90S. THE NAM HOWEVER REMAINS 8-10 DEGREES COOLER AND IS SIMPLY NOT
AS STRONG WITH THE RIDGING ALOFT. THE ECMWF SEEMS TO SUPPORT THE
GFS/S SOLUTION...SO OVERALL HAVE TAKEN A BLEND TO AVOID A DRAMATIC
SWING FROM YESTERDAY/S FORECAST BUT HAVE LEANED TOWARD THE WARMER
GFS. THIS WARMING TREND CONTINUES INTO THE EARLY PART OF THE WEEK
WITH THE 00Z GFS MUCH WARMER THAN THE 12Z RUN YESTERDAY...AND
WARMER THAN THE ECMWF IS IMPLYING. HAVE AGAIN TAKEN A BLEND...
TRYING TO ACCOUNT FOR RUN-TO-RUN DIFFERENCES AND FACTORING IN THE
ECMWF SOLUTION. OVERALL THOUGH TEMPS REMAIN ABOVE NORMAL THROUGH
THE PERIOD.
AS FOR POPS...THE EXTENDED LOOKS MOSTLY DRY...THOUGH AS THE UPPER
RIDGE BEGINS TO BREAK DOWN BY MONDAY NIGHT MOISTURE WILL BE ABLE
TO WORK FIRST INTO NORTH GEORGIA AND THEN FURTHER SOUTH. POPS
REMAIN SLIGHT CHANCE AT BEST BUT WITH A TYPICAL SUMMERLIKE DIURNAL
TREND TO THE CONVECTIVE POTENTIAL. BOTH THE GFS AND ECMWF WANT TO
BRING MOISTURE FROM THE ATLANTIC OVER FLORIDA AND EVENTUALLY INTO
PARTS OF GEORGIA...WITH THE GFS FASTER AND MORE IMPRESSIVE WITH
THE MOISTURE AMOUNTS. OF COURSE...THE GFS IS LIKELY OVERDONE WITH
THIS BUT THE TRENDS WILL HAVE TO BE MONITORED THROUGH SUBSEQUENT
FORECASTS.
TDP
&&
.AVIATION...
12Z UPDATE...
MORNING MVFR CIGS WILL REMAIN CONFINED TO SOUTHERN TAF SITES /CSG
AND MCN/. AREAL COVERAGE OF AFTERNOON CONVECTION REMAINS THE
QUESTION...BUT NAM...GFS...AND WRF COMING INTO AGREEMENT WITH MORE
COVERAGE. RAISED TSRA CHANCES TO TEMPO IN NORTHERN GEORGIA
TAFS...BUT TIMING WILL BE EARLY AFTERNOON. LIGHT WEST WINDS FOR THE
DURATION OF THE PERIOD. MORNING STRATUS AGAIN SATURDAY...BUT WILL
NOT BITE ON CIGS AT THIS POINT.
//ATL CONFIDENCE...12Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS...WITH MODERATE CONFIDENCE ON
AFTERNOON TSRA COVERAGE.
27
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 83 59 85 60 / 40 20 10 5
ATLANTA 80 62 84 63 / 30 10 10 5
BLAIRSVILLE 78 55 81 54 / 20 20 10 10
CARTERSVILLE 79 58 87 57 / 30 20 20 10
COLUMBUS 84 61 86 60 / 5 10 5 5
GAINESVILLE 81 61 85 61 / 40 20 10 10
MACON 85 58 86 58 / 20 5 5 5
ROME 83 59 87 58 / 30 20 20 10
PEACHTREE CITY 81 56 87 56 / 20 10 10 5
VIDALIA 86 64 88 64 / 10 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
709 AM CDT FRI APR 27 2012
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
/ISSUED AT 330 AM FRI APR 27 2012/
UPPER AIR PATTERN A BIT COMPLICATED WITH STRONG UPPER TROF MOVING
ACROSS THE PACIFIC NW AND THEN CLOSING OFF LATTER TODAY INTO THE
NORTHERN PLAINS AND REMAINING QUASI-STATIONARY IN THE DKTS OVER
THE WEEKEND. THE OTHER TROUGH...WHICH WILL BE THE MAIN PLAYER IN OUR
WEATHER IS CURRENTLY LIFTING OUT OF THE SW U.S. AND WILL DAMPEN AS
IT ENCOUNTERS BLOCKING RIDGE ACROSS UPPER MIDWEST. MODELS ARE A
BIT LESS AGGRESSIVE ON QPF OUTPUT THAN THEY WERE 24 HOURS
AGO...BUT STILL IN FAIRLY GOOD AGREEMENT THAT A PERSISTENT PERIOD
OF RAIN WILL DEVELOP TONIGHT AND INTO SATURDAY ACROSS MOST OF OUR
AREA.
FIRST WAVE OF -RA IS ADVANCING INTO WC/SW MN...BUT IS BATTLING WITH
DRY ELY FLOW...BUT A FEW METARS ARE SHOWING -RA OUT OF MID CLOUDS.
HRRR SEEMS TO HAVE A PRETTY GOOD HANDLE ON THIS FIRST SHOT OF -RA
GRADUALLY WEAKENING IT AS IT CONTINUES TO MOVE EAST INTO DRY RIDGE
OF HIGH PRESSURE. SO LEFT AREAS FROM AROUND STAPLES TO HCD TO AEL
DRY FOR TODAY. ALSO BUMPED UP HIGH TEMPERATURES JUST A BIT FOR THOSE
AREAS WHICH SHUD REMAIN DRY. AFTERNOON RH SHUD DROP INTO THE MID 20
PERCENT RANGE ACROSS MOST OF WI CWA AND UPPER 20S PERCENT FOR
ADJOINING AREAS OF MN. CLOUD COVER AND A BIT OF -RA WILL KEEP AFTN
RH ABOVE 30 PERCENT REMAINDER OF AREA. SURFACE PRESSURE GRADIENT
TIGHTENS DURING THE DAY IN RESPONSE TO PRESSURE FALLS AHEAD OF LOW
PRESSURE TROF ACROSS THE DKTS INTO W KS. WILL SEE GUSTS THIS AFTN 30
MPH OR BETTER ACROSS MUCH OF WC INTO SC MN.
TONIGHT THE PIECES COME TOGETHER BETTER FOR PRECIPITATION AS THE SW
U.S. WAVE LIFTS TOWARD AREA PROVIDING A RATHER LENGTHY PERIOD OF
ISENTROPIC LIFT. DRY ELY FLOW WILL PROVIDE A GOOD SETUP FOR WETBULB
COOLING AS LIFT FROM THE APPROACHING TROF FURTHER COOLS THE COLUMN.
DON`T EXPECT ANY SNOW ACCUMS...BUT PROGGED SOUNDINGS DO BECOME COLD
ENUF FOR A MIX ACROSS MOST OF THE AREA. QPF AMOUNTS FROM TONIGHT
INTO SATURDAY NIGHT WILL SHOW A WIDE RANGE FROM PERHAPS AN INCH OUT
IN WC MN TO A TRACE TO A FEW HUNDREDTHS IN NW PTN OF WI CWA.
RIDGE REASSERTS ITSELF ON SUNDAY AS THE SW U.S. TROF SHEARS OUT TO
THE EAST AND BECOMES ABSORBED BY THE RIDGE AND DKTS UPPER LOW BEGINS
TO LIFT INTO SASK.
MODERATING TEMPS NEXT WEEK AS UPPER FLOW BECOMES ZONAL TO SW...BUT
PATTERN DOES LOOK ACTIVE...ESPECIALLY ON TUESDAY INTO WEDNESDAY AS A
STRONG TROF MOVES ACROSS THE REGION.
&&
.AVIATION.../12Z TAF ISSUANCE/
BAND OF ELEVATED SHOWERS HAS MOVED INTO SW MN THIS MORNING...BUT
VERY DRY LOW LEVELS HAS MADE IT DIFFICULT FOR MUCH OF THIS
ACTIVITY TO MAKE IT TO THE GROUND. HRRR HANDELING THIS MORNING
ACTIVITY WELL AND IT CONTINUES TO ADVERTISE THIS AREA OF SHOWERS
DIMINISHING THROUGH THE MORNING AS THE FORCING WANES AND IT
CONTINUES TO ENCOUNTER THE DRY AIR. AFTER THAT DO NOT ANTICIPATE
ANY PRECIP AT TERMINALS UNTIL WAVE CURRENTLY EXITING COLORADO MOVES
UP THIS DIRECTION. SLOWED QUITE A BIT THE ONSET OF PRECIP AT TAFS
AS DRY AIR LOOKS TO BE RATHER DIFFICULT TO OVERCOME. LOOKING AT
LATEST NAM REFLECTIVITY FORECAST...CURRENT TAFS MAY NOT BE SLOW
ENOUGH. EXPECT CIGS TO REMAIN VFR UNTIL THE END OF THE TAF AT RWF
AND MAYBE MSP. PRESSURE GRADIENT WILL BE STRENGTHENING THROUGH THE
DAY...SO DO LIKE GOING STRONG ESE WINDS IN TAFS. IS INTERESTING TO
NOTE THAT STRONGEST WINDS OFF THE 06Z NAM COME BETWEEN 00Z AND 06Z
SAT...WHEN ITS SHOWING AXN/RWF COULD SEE 25G35KT TYPE WINDS. KEPT
P-TYPE ALL LIQUID AT THIS POINT...WITH CHANCES FOR SNOW LOOKING
MARGINAL AT BEST RIGHT NOW WITH THINGS STAYING JUST WARM ENOUGH TO
KEEP PRECIP AS RAIN.
KMSP...WITH BEST FORCING AND DEEPER MOISTURE NOT PEGGED TO COME
OVER THE FIELD UNTIL AFTER 06Z...DELAYED PRECIP ONSET QUITE A
BIT. COULD CERTAINLY SEE PRECIP EARLIER THAN 06Z IF RATES ARE
STRONG ENOUGH TO FORCE THE RAIN THROUGH ABOUT 8K FT OF DRY AIR. AT
THE SAME TIME...THERE IS A CHANCE NO RAIN IS SEEN THIS TAF PERIOD
AT ALL. FOR CIGS...ASSUMING RAIN STARTS BY 09Z...THEN IT IS LIKELY
THAT AT SOME POINT DURING SAT MORNING CIGS WILL BECOME MVFR. FOR
WINDS...THEY LOOK STRONG THE WHOLE 30 HOURS...BUT FAIRLY PERSISTENT
IN THE 090-120 DIRECTION.
//OUTLOOK...SATURDAY THROUGH TUESDAY...
.SAT-SAT NGT...-SHRA DIMINISHING OVERNIGHT. IFR/MVFR CIGS LIKELY
WITH PERIOD OF MVFR VIS.
.SUN...IFR/MVFR CIGS LIKELY WITH PERIODS OF LIGHT RAIN EARLY.
.MON...IFR/MVFR CIGS EARLY...BECOMING VFR IN THE AFTERNOON.
.TUE...CHC -TSRA AFTERNOON INTO THE NIGHT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR ANOKA-BENTON-
DOUGLAS-ISANTI-SHERBURNE-STEARNS-TODD-WASHINGTON.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR CHISAGO-KANABEC-
MILLE LACS-MORRISON.
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR DUNN-PEPIN-PIERCE-
ST. CROIX.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR BARRON-CHIPPEWA-
EAU CLAIRE-POLK-RUSK.
&&
$$
BAP/MPG
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1038 AM CDT FRI APR 27 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.UPDATE...
THE SEVERE WEATHER THREAT CONTINUES FOR THIS AFTERNOON AND
EVENING...ESPECIALLY FOR AREAS ALONG THE U.S. 71 CORRIDOR IN
SOUTHEASTERN KANSAS AND WESTERN MISSOURI.
A STRONG SHORTWAVE CONTINUES TO PUSH EAST OVER WESTERN KANSAS LATE
THIS MORNING...WITH AN ASSOCIATED WELL DEVELOPED AREA OF LOW
PRESSURE AT THE SURFACE. AS OF 15Z...A WARM FRONT STRETCHED FROM
NEAR WICHITA TO MIAMI OK TO LITTLE ROCK.
THE WARM FRONT/WARM SECTOR OF THIS SYSTEM SHOULD BEGIN TO
OVERSPREAD THE WESTERN PORTIONS OF THE CWA THIS AFTERNOON...LIKELY
MIXING NORTHEAST TO ROUGHLY U.S. 65 BY 00Z. I DO HAVE SOME CONCERN
AS TO WHETHER MODEL GUIDANCE IS UNDER-PLAYING THE SPEED OF THE
WARM FRONT...AS A COMBINATION OF STRONG PRESSURE AND HEIGHT
FALLS...ALONG WITH A BIT OF OCCASIONAL SUNSHINE NORTH OF THE WARM
FRONT...COULD RESULT IN VERY RAPID NORTHWARD MOVEMENT LATE THIS
AFTERNOON.
WHILE THE WARM SECTOR IS CURRENTLY QUITE CAPPED PER 12Z
RAOBS...A SERIES OF VORT MAXES WRAPPING AROUND THE MAIN UPPER
LOW/SHORTWAVE WILL ACT TO ERODE MUCH OF THAT INHIBITION BY 21Z. AT
THE SAME TIME...AN APPROACHING...AND PERHAPS SURGING...DRYLINE AND
COLD FRONT WILL APPROACH EASTERN KANSAS...SERVING AS THE FOCUS FOR
THUNDERSTORM DEVELOPMENT BETWEEN 18Z AND 21Z WEST OF THE CWA.
CELLS WILL LIKELY MOVE INTO THE U.S. 71 CORRIDOR BETWEEN 21Z AND
23Z. 12Z NAM AND 12/13Z RUC CONTINUE TO SUPPORT SUPERCELLS...WITH
AN ASSOCIATED RISK OF VERY LARGE HAIL...STRONG WINDS...AND
TORNADOES. THE TORNADO THREAT APPEARS TO BE MAXIMIZED ACROSS
EASTERN KANSAS AND THE WESTERN TIER OR TWO OF COUNTIES IN
MISSOURI...EXTENDING SOUTH INTO NORTHEASTERN OKLAHOMA. WITH STRONG
THERMODYNAMIC AND KINEMATIC PARAMETERS IN PLACE...AN ISOLATED
STRONG TORNADO CAN NOT BE RULED OUT ACROSS THIS AREA.
STORMS WILL CONTINUE TO PUSH EAST THIS EVENING TOWARD THE U.S. 65
CORRIDOR...THOUGH THE EASTERN EXTENT OF THE SEVERE WEATHER THREAT
REMAINS DEPENDENT ON HOW FAR THE WARM SECTOR BUILDS INTO MISSOURI.
THE OVERALL SEVERE THREAT LATE TONIGHT SHOULD BE MITIGATED A BIT
BY A COOLING/INCREASINGLY INHIBITED BOUNDARY LAYER...THOUGH
ISOLATED SEVERE STORMS WILL BE POSSIBLE THROUGH MIDNIGHT.
BOXELL
&&
.DISCUSSION...
MAIN CONCERNS FOR THE FORECAST PACKAGE FOCUS ON THE POTENTIAL FOR
SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING.
EARLY MORNING CONDITIONS ACROSS THE OZARKS AND SOUTHEASTERN
KANSAS HAVE DEWPOINTS IN THE 50S WITH TEMPERATURES IN THE 60S
NORTH OF A FRONT LAID OUT ACROSS CENTRAL ARKANSAS. THIS IS THE
COLD FRONT THAT MOVED THROUGH THE OZARKS YESTERDAY MORNING AND IT
WILL BEGIN TO MOVE ITS WAY NORTH AS A WARM FRONT TODAY AND BRING A
RETURN OF SOUTHERLY WINDS AND ADDITIONAL MOISTURE TO THE REGION.
THIS WILL BRING THE POTENTIAL FOR SEVERE WEATHER TO THE REGION
THIS AFTERNOON AND EVENING.
CURRENT SHORT TERM MODELS HAVE THE WARM FRONT LIFTING THROUGH THE
OZARKS THROUGH THE DAY TODAY AS SURFACE LOW PRESSURE NOW OVER
EASTERN COLORADO AND WESTERN KANSAS TRACKS EAST ACROSS THE PLAINS.
THIS WILL OCCUR IN RESPONSE TO THE UPPER LEVEL SHORT WAVE/CLOSED
LOW MOVING EAST. THE LEFT EXIT REGION OF A 250MB/500MB JET MAX WILL
BEGIN TO ROUND THE BEND OF THE UPPER TROUGH AND PROVIDE GOOD
DIFFLUENCE ALOFT. THIS WILL BE OCCURRING OVER A REGION OF
INCREASING INSTABILITY WITH MLCAPE VALUES VIA THE NAM UP TO AROUND
2000 J/KG...WITH 150 J/KG IN THE 0-3 KM LAYER. WHILE THE MODELS DO
TEND TO OVER DO THE LOW LEVEL CAPE...EVEN TAKING HALF OF THE
MODEL OUTPUT WOULD BE ENOUGH FOR SEVERE STORMS TO DEVELOP. THIS
WILL OCCUR IN CONJUNCTION WITH 0-3 KM BULK SHEAR AROUND 50-60
KTS AND 0-1 KM STORM RELATIVE HELICITY VALUES OVER 400M2/S2.
WOULD EXPECT THAT AREAS WEST OF HIGHWAY 65 IN GENERAL WILL HAVE
THE BEST CHANCES FOR SEVERE STORMS...WITH LARGE HAIL...DAMAGING
WINDS AND TORNADOES ALL POSSIBLE. WILL NEED TO MONITOR THE
PROGRESS OF THE WARM FRONT AND HOW CLOSE TO THE REGION THE DRY
LINE GETS TODAY.
AS THE UPPER LEVEL TROUGH LIFTS OUT OF THE REGION FRIDAY NIGHT A
SECONDARY SLOW MOVING CUTOFF LOW OVER THE NORTHERN PLAINS WILL AID
IN DEVELOPING A SLIGHTLY SOUTHWESTERLY UPPER LEVEL FLOW OVER THE
WESTERN CONUS THROUGH THE WEEKEND. THIS WILL NOT ONLY HELP TO KEEP
THE FRONT WANDERING ACROSS MISSOURI BEFORE THE UPPER LOW LIFTS
NORTH SUNDAY NIGHT...IT WILL CONTINUE TO BRING UPPER LEVEL
MOISTURE INTO THE REGION THROUGH EARLY NEXT WEEK. THIS WILL KEEP
CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR THE
WEEKEND AND INTO TUESDAY OF NEXT WEEK.
THE REGION MAY SEE A BRIEF RESPITE FOR THE MIDDLE OF NEXT WEEK
BEFORE ANOTHER FRONT ATTEMPTS TO PUSH THROUGH THE OZARKS. THE
FRONT THEN LOOKS TO GET HUNG UP ACROSS MISSOURI AS UPPER LEVEL
RIDGING ATTEMPTS TO BUILD ACROSS THE SOUTHWESTERN CONUS FOR LATE
NEXT WEEK...RETURNING NORTHWEST UPPER FLOW OVER THE OZARKS.
HATCH
&&
.AVIATION...
LOW LEVEL WIND SHEAR WILL PERSIST THIS MORNING AS A STRONG LOW
LEVEL JET STREAM SHIFTS OVER THE REGION. MEANWHILE...A WARM FRONT
WILL SHIFT NORTH TOWARDS THE AREA STARTING THIS MORNING. MVFR
CEILINGS ARE EXPECTED TO DEVELOP AHEAD OF THE FRONT...AS WELL AS
SCATTERED SHOWERS AND THUNDERSTORMS. STRONG AND GUSTY SOUTHEAST
WINDS WILL ALSO DEVELOP...WITH GUSTS OVER 30 KNOTS LIKELY INTO
THIS AFTERNOON. WE WILL THEN GET A BREAK IN THE PRECIPITATION AND
MVFR CEILINGS LATER THIS AFTERNOON. SCATTERED STRONG TO SEVERE
THUNDERSTORMS ARE THEN EXPECTED TO DEVELOP ACROSS SOUTHEASTERN
KANSAS AND WESTERN MISSOURI FROM LATE THIS AFTERNOON INTO THIS
EVENING. WITH TIMING SOMEWHAT IN QUESTION...WENT WITH A PREVAILING
VCTS GROUP FOR NOW AT KJLN AND KSGF. MOST IF NOT ALL ACTIVITY IS
EXPECTED TO REMAIN NORTH OF KBBG.
SCHAUMANN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
735 AM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA EARLY THIS MORNING...THEN
JUST SOUTH OF THE REGION THIS AFTERNOON AND EVENING. THE FRONT WILL
DRIFT BACK N OVER THE AREA LATE SATURDAY...THEN SOUTH OF THE AREA
GAIN SUNDAY NIGHT. HIGH PRESSURE WILL BUILD ACROSS NORTH OF THE AREA
MONDAY...THEN DRIFT OFFSHORE TUESDAY AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 700 AM FRIDAY...NO SIGNIFICANT CHANGES WITH UPDATE. ALL
CONVECTIVE ACTIVITY HAS MOVED OFFSHORE WITH SHRT WV AND FRONT HAS
REACHED NRN OBX...ON TRACK TO MOVE ACROSS AREA DURING MORNING. SCU
HAS DEVELOPED OVER NRN 2/3 OF AREA AND EXPECTED TO SPREAD S WITH
FRONTAL PROGRESSION...THEN DIMINISH FROM N TO S DURING AFTN AS DRY
AIR MOVES IN. LATEST NAM12 AND HRRR DO INDICATE PCPN PSBL OVER SRN
ONSLOW COUNTY LATE AFTN WITH FRONT AND SEA BREEZE INTERACTION...WILL
LET DAY SHIFT TAKE A LOOK FOR PSBL ADDING POPS WITH LATER UPDATE.
/PREVIOUS DISCUSSION.
AS OF 300 AM FRIDAY...CURRENT CONVECTIVE ACTIVITY ALONG SRN OBX WILL
MOVE OFFSHORE NEXT HOUR OR SO BUT WILL CONTINUE TO CARRY SLGT CHC
POPS ALONG COAST EARLY THIS MORNING UNTIL FRONTAL PASSAGE AND SHRT
WV MOVES OFFSHORE. MODELS IN DECENT AGREEMENT OF FRONT BACKDOORING
THROUGH AREA 6AM-10AM...BRINGING SLIGHTLY COOLER AND DRIER AIR MASS
TO AREA...WITH MOST NOTICEABLE CHANGE IN TEMPS OVER NRN OBX. WEAK
SUBSIDENCE AND MORE STABLE CONDITIONS WILL KEEP PCPN THREAT S OF
AREA DURING THE DAY. MINOR ADJUSTMENTS TO MAX TEMPS WITH LATEST MOS
BLEND. HIGHS MAINLY LOW-MID 70S EXCEPT LOW-MID 60S OBX.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
AS OF 300 AM FRIDAY...HIGH PRES EXTENDING OVER AREA WILL PRODUCE
FAIR WX CONDITIONS THIS EVENING...THEN NEXT SHRT WV APPROACHING FROM
W WILL INDUCE LOW PRES WAVE ALONG FRONT TO S OF AREA
OVERNIGHT...WITH THREAT OF SHOWERS SPREADING OVER ALL BUT EXTREME NE
SECTIONS BY MORNING. BASED ON MODEL AGREEMENT...INCREASED POPS TO
50% OVER SRN SECTIONS...TAPERING TO 30% N-NE. MINOR ADJUSTMENTS TO
MIN TEMPS...MAINLY LOWERED SLIGHTLY AS RADIATIONAL COOLING
CONDITIONS MAY ALLOW TEMPS TO DROP QUICKLY THIS EVENING.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
AS OF 330 AM FRI...RATHER TRICKY LONG TERM FCST AS A FRONT WAVERS
BACK AND FORTH ACROSS THE REGION THIS WEEKEND THROUGH EARLY NEXT
WEEK. FOR SAT...UNSETTLED WEATHER IS EXPECTED AS E NC IS UNDER CAA
TYPE REGIME WITH HIGH PRES TO THE NORTHEAST RIDGING INTO THE AREA
WITH EASTERLY SFC FLOW. AT THE SAME TIME...H85 WARM FRONT WILL LIFT
NORTH THROUGH E NC AS SWRLY FLOW ALOFT INC. THIS WILL BRING INC IN
ISENTROPIC LIFT...AND WITH FRONTAL INVERSION DEVELOPING...A RATHER
COOL DAY WILL BE ON TAP WITH WIDESPREAD LOW CLOUDS AND SCT PRECIP.
THERE IS A CHANCE FOR SOME THUNDER FOR SOUTHERN PORTIONS OF THE FA
AS ELEVATED CAPE WORKS ITS WAY INTO THE REGION FROM THE SW. WITH
DEEP LAYER SHEAR PRESENT...A FEW THUNDERSTORMS MAY BE PRESENT IN THE
SCT SHOWER ACTIVITY.
SFC HIGH WILL WEAKEN/MOVE FURTHER OFFSHORE SAT NIGHT...ALLOWING FOR
RETURN SFC FLOW TO DEVELOP AND SCOUR OUT LOW CLOUDS/PRECIP. THE SFC
WARM FRONT WILL BE SITUATED ACROSS THE VA/NC BORDER SUN MORNING...
BEFORE DROPPING SOUTH AS A COLD FRONT DURING THE DAY. LARGE TEMP
GRADIENT POSSIBLE SUNDAY...WITH TEMPS IN THE WARM SECTOR ACROSS SW
ZONES REACHING WELL INTO THE 80S...WITH NEAR 70 READINGS ACROSS THE
NORTHERN OBX. TEMPS WILL BE NEAR AVG FOR OVERNIGHT LOWS SUN NIGHT
THROUGH MON NIGHT WITH CLOUDINESS EXPECTED...WITH HIGHS A BIT BELOW
NORMAL DUE TO THE NE FLOW AND MOSTLY CLOUDY SKIES. BUILDING HEIGHTS
EXPECTED FOR TUE THROUGH MID WEEK...WITH TEMPS INCREASING INTO THE
80S EACH AFTERNOON.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /12Z FRIDAY THROUGH 12Z SATURDAY/...
AS OF 720 AM FRIDAY...VFR PREVAILING THROUGH THIS EVENING...THEN
SOME LOWER CLOUDINESS PSBL LATE TONIGHT. BACKDOOR FRONT WILL PUSH
THROUGH AREA FROM N THIS MORNING WITH MAIN EFFECT BEING WIND SHIFT
TO N. SHRT WV HAS MOVED OFFSHORE AND NO CONVECTIVE ACTIVITY EXPECTED
WITH FRONT. SCU CIGS 5-6K FT WILL SPREAD S THIS MORNING...THEN
DIMINISH THIS AFTN. NEXT SHRT WV WILL SPREAD CHC OF SHOWERS SW TO NE
OVERNIGHT...AND DEVELOPING EASTERLY FLOW MAY RESULT IN SOME MVFR
CIGS LATE...ESPECIALLY KOAJ AND KEWN...BUT LOW CONFIDENCE AT THIS
TIME.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM FRI...PERIOD OF MVFR OR POSSIBLY IFR FOR SAT AS FRONTAL
INVERSION DEVELOPS. SCT SHOWERS WILL BE POSSIBLE. CLOUDS SHOULD LIFT
AND SCATTER ON SAT NIGHT AS FRONT LIFTS NORTH OF THE REGION. THE
FRONT WILL SLOWLY DROP BACK SOUTH DURING THE DAY SUNDAY...WITH AN
INC IN CLOUDS AGAIN EXPECTED...ESPECIALLY INTO SUNDAY NIGHT AND
MONDAY. MAY AGAIN SEE CLOUDS LOWER TO MVFR CAT.
&&
.MARINE...
SHORT TERM /TODAY AND TONIGHT/...
AS OF 720 AM FRIDAY...FRONT MOVING THROUGH NRN MOST WATERS AND ON
TRACK TO MOVE ACROSS AREA THIS MORNING...WITH POST-FRONTAL NRLY
SURGE. GUSTS UP TO 30 KT OBSERVED UPSTREAM...THUS NO CHANGE IN SCA
FOR SOUNDS THROUGH THIS MORNING...AND OVER COASTAL WATERS INTO THIS
AFTN DUE TO LINGERING 6 FT SEAS.
/PREVIOUS DISCUSSION/
AS OF 300 AM FRIDAY...MODELS CONTINUE TO APPEAR SLIGHTLY UNDERDONE
WITH POST-FRONTAL CAA SURGE THIS MORNING...AND EXPECT PERIOD OF
GUSTS TO 25 KT PER CURRENT OBS UPSTREAM...AND NO CHANGES TO SCA FOR
ALL OF WATERS. WINDS AND SEAS WILL GRADUALLY DIMINISH BELOW 15 KT
ALL WATERS THIS AFTN AND EVENING...THEN INCREASE SRN WATERS
OVERNIGHT WITH TIGHTENING PRES GRAD.
LEANED TO PREVIOUS FCST AND WW3 FOR SEAS.
LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 330 AM FRI...WINDS WILL BE EASTERLY SAT AS HIGH PRES RIDGES
INTO E NC FROM THE NE. RETURN FLOW WILL DEVELOP SAT EVENING AS FRONT
LIFTS NORTH OF THE AREA. THE SW FLOW WILL BE SHORT LIVED AS NE WINDS
DEVELOP ON SUNDAY WITH SFC COLD FRONT DROPPING SOUTH THROUGH THE
WATERS ONCE AGAIN. WINDS SHOULD REMAIN JUST BELOW SCA THROUGH THE
PERIOD WITH SEAS 2 TO 4 FEET. SOME 5 FOOT SETS POSSIBLE ACROSS THE
OUTER WATERS. FLOW BECOMES S TO SW TUE INTO WED AS A RIDGE OF HIGH
PRES BUILDS IN FROM THE WEST.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR AMZ130-
135.
SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR AMZ150-
152-154-156-158.
&&
$$
SYNOPSIS...CTC/JME
NEAR TERM...JBM/JME
SHORT TERM...JBM
LONG TERM...TL
AVIATION...JBM/TL
MARINE...JBM/JME/TL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1053 AM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTHWARD ACROSS NORTH CAROLINA THIS
MORNING...AND SHOULD STALL NEAR THE SOUTH CAROLINA BORDER THIS
AFTERNOON. THE FRONT IS EXPECTED TO LIFT BACK TO THE NORTH ON
SATURDAY BRIEFLY...BEFORE BEING DRIVEN BACK SOUTHWARD ON SUNDAY BY
HIGH PRESSURE MOVING ACROSS THE GREAT LAKES. THE FRONT WILL WASH OUT
EARLY NEXT WEEK AS THE HIGH MOVES OFF THE EAST COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
1030 AM UPDATE...14Z SURFACE ANALYSIS INDICATES THAT A SURFACE
BOUNDARY LIES FROM NE GA..EAST ACROSS UPSTATE SC THROUGH THE
CHARLOTTE AREA. THE BOUNDARY SEPARATES LOW 60`S DEWPOINT AIR FROM
MIDDLE 50S OR SO TO THE NORTH. THIS BOUNDARY SHOULD SERVE AS A FOCUS
FOR AFTERNOON CONVECTION. MESO MODELS INDICATE THAT SHOWERS AND
THUNDERSTORMS WILL MOVE EAST OUT OF NORTHERN GA INTO THE WESTERN
UPSTATE BY 18Z AND THEN ACROSS THE REMAINDER OF THE UPSTATE INTO NC
AROUND THE SOUTHERN SUBURBS OF CHARLOTTE. WILL ADJUST THE POP FIELD
TO INCREASE COVERAGE OF SHOWERS/STORMS INTO THE NUMEROUS CATEGORY
OVER A LARGE PORTION OF NE GA AND THE SC UPSTATE. WILL SHOW SCT TYPE
COVERAGE NORTH TO AROUND THE NC BORDER. NAM BUBBLES UP CAPES TO
NEAR 2000J/KG THIS AFTERNOON ACROSS UPSTATE SC...SO A COUPLE
SEVERE STORMS WITH LARGE HAIL NOT OUT OF TEH QUESTION.
ALSO...12Z NAM AND OTHER MESO MODELS INDICATE A SOMEWHAT TRANSIENT
CLUSTER OF SHOWERS/STORMS THIS AFTERNOON INTO THE EVENING ASSOCIATED
WITH AN UPPER VORT. HENCE...WILL FOLLOW THE LEAD OF THE NAM AND MOVE
POPS OUT OF THE FORECAST AREA THIS EVENING AS A NE FLOW/WEDGE
DEVELOPS OVERNIGHT. THE NAM DOES NOT GENERATE ANY QPF TONIGHT INTO
SAT...SO WILL KEEP MENTIONABLE POPS OUT. EXPECT MOSTLY CLOUDY
CONDITIONS TO DEVELOP BY LATE AFTERNOON CONTINUING INTO SAT.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...THE SHORT RANGE REMAINS IN A STATE OF FLUX
BECAUSE OF UNCERTAINTY WITH THE PLACEMENT OF THE SURFACE BOUNDARY.
THE RELATIVELY FLAT UPPER FLOW ACROSS MUCH OF THE SOUTHEAST WILL
BUCKLE OVER TIME...WITH AN AMPLIFYING UPPER RIDGE...AS THE OMEGA
BLOCK TO OUR NORTH DISINTEGRATES SUNDAY AND INTO MONDAY. THERE DOES
NOT APPEAR TO BE MUCH IN THE WAY OF UPPER FORCING...BUT A SURFACE
BOUNDARY WILL PROVIDE LOW LEVEL FORCING AND FOCUS FOR CONVECTIVE
DEVELOPMENT...FIRST ON SATURDAY EARLY IN THE DAY AS IT MOVES
NORTHWARD AS A WARM FRONT. HAVE RAISED PRECIP CHANCES AND CLOUD
COVER A BIT OVER THE NORTHERN ZONES BASED ON THE SREF. A
CORRESPONDING DOWNWARD ADJUSTMENT TO MAX TEMPS WAS ALSO MADE. AFTER
A RELATIVELY QUIET SATURDAY NIGHT...THE FRONT IS EXPECTED TO BE
DRIVEN BACK SOUTHWARD BY THE NEXT SURFACE HIGH MOVING OVER THE
WESTERN GREAT LAKES...BUT PERHAPS NOT UNTIL LATE IN THE DAY. THE
MODEL GUIDANCE WAS ALL UNIFORMLY QUITE A BIT WARMER THAN THE
PREVIOUS FCST BECAUSE OF THE LATER TIMING...SO AN UPWARD ADJUSTMENT
OF ONE OR TWO CATEGORIES WAS MADE. THIS COULD EASILY GO WRONG AND BE
COOLER IF THE TIMING OF THE FRONT IS EARLIER THAN PLANNED. HAVE ALSO
RAISED MIN TEMPS SUNDAY NIGHT WITH INCREASED CLOUD COVER.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...NOT MUCH IN THE LATEST OPERATIONAL MODELS IS
FOUND COMPELLING ENOUGH TO MAKE ANY SIGNIFICANT CHANGES TO THE
MEDIUM RANGE. AT LEAST THROUGH MID WEEK WE SHOULD BE UNDER THE
INFLUENCE OF UPPER RIDGING THAT WILL KEEP THE BEST UPPER FORCING TO
OUR NORTH...WITH THE WESTERN CAROLINAS ESSENTIALLY IN A WARM SECTOR.
THAT SHOULD FAVOR LOW CHANCES OF MAINLY DIURNAL CONVECTIVE PRECIP.
THE GFS DEVELOPS IN INTERESTING UPPER LOW LATE IN THE WEEK OVER THE
SOUTHEAST WHICH WOULD MEAN A BETTER CHANCE OF PRECIP...BUT THAT
FEATURE IS WELL OFFSHORE ON THE ECMWF...SO WE WILL NOT BITE ON IT.
&&
.AVIATION /15Z FRIDAY THROUGH TUESDAY/...
AT KCLT...A TRICKY FCST FOR VSBY THIS MORNING. LOW TDD/S AND CALM
CONDS WILL MAKE AN MVFR BR POSSIBLE FOR THE FIRST COUPLE HRS OF THE
PERIOD. LEFT OUT OF TAF BASED ON 10SM OCCURRING RIGHT NOW AND THE
POTENTIAL FOR WINDS TO PICK UP A TAD AFT 12Z. AFTERNOON CONVECTION
LOOKS TO BE CLOSE TO THE TERMINAL. SHARP BOUNDARY JUST TO THE
SOUTH...WITH HRRR SHOWING STORMS RIDING ON AND TO THE N OF THE
BOUNDARY AND PERHAPS IMPINGING UPON THE AREA AROUND 20Z. WILL LEAVE
VCTS OUT OF THE TAF PER COORDINATION WITH CWSU. WARM FRONT MOVES
OVER WEDGE TONIGHT AND MVFR CIGS WILL BE POSSIBLE AFT 09Z AS WEDGE
BOUNDARY SHIFTS NE.
ELSEWHERE...TOUGH CALL ON THE MTN VSBY THIS MORNING WITH WINDS
PICKING UP AND THEN SETTLING DOWN. WILL KEEP THE IFR MENTION AT KAVL
THROUGH 14Z. OTHER SITES...IT LOOKS LIKE VFR CIGS/VSBY THROUGH THE
MORNING WILL PREVAIL. EXPECT VCTS THIS AFTERNOON ACROSS THE NON/NC
SITES. STATIONARY FRONT WILL MOVE LITTLE AND MAKE FOR A GOOD AREA OF
CONVECTIVE DEVELOPMENT.
OUTLOOK...A FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF THE AREA
THROUGH THE WEEKEND...RESULTING IN CONTINUATION OF UNSETTLED
WEATHER/PM SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS THROUGH THAT
TIME.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...LG
SHORT TERM...PM
LONG TERM...PM
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
724 AM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL DROP SOUTHWARD ACROSS NORTH CAROLINA THIS
MORNING...AND SHOULD STALL NEAR THE SOUTH CAROLINA BORDER THIS
AFTERNOON. THE FRONT IS EXPECTED TO LIFT BACK TO THE NORTH ON
SATURDAY BRIEFLY...BEFORE BEING DRIVEN BACK SOUTHWARD ON SUNDAY BY
HIGH PRESSURE MOVING ACROSS THE GREAT LAKES. THE FRONT WILL WASH OUT
EARLY NEXT WEEK AS THE HIGH MOVES OFF THE EAST COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
0715 AM UPDATE...MADE SOME MINOR ADJUSTMENTS TO TEMP/DEWPOINT TRENDS
AND LOWERED POPS SOUTHERN PERIPHERY. WILL ALSO BE CANCELLING THE
DENSE FOG ADVISORY AS WINDS HAVE PICKED UP ACROSS THE FRENCH BROAD
VALLEY AND MIXED FOG OUT.
AS OF 330 AM...THE LATEST LAPS ANALYSIS SHOWS THE COLD FRONT LOCATED
STILL LOCATED TO THE NW OF THE CWFA WITH GOOD MOISTURE POOLING AHEAD
ACROSS ERN TN AND INTO THE WRN NC MTNS. THIS HAS HELPED MAINTAIN
ISOL/SCT -SHRA ACROSS THE WRN ZONES. THIS ACTIVITY SHOULD WANE
THROUGH MORNING AS THE PRESSURE TROF BROADENS AND SILENTLY PUSHES
SOUTH. MORNING FG IS SETTING UP WHERE EXPECTED...MAINLY ACROSS THE
WRN HALF OF THE CWFA WHERE MOST OF THE RAIN FELL YESTERDAY. NOTHING
TOO WIDESPREAD AS FAR AS DENSE FG...BUT THIS WILL BE MONITORED AS
TDDS ARE PRETTY LOW ADJACENT TO THE MTNS AND SC PIEDMONT. EXPECT THE
MAIN TSTM ACTIVITY TO INSTIGATE WITHIN THE PRESSURE TROF...WHICH
WILL BE ACROSS THE UPSTATE INTO NE GA. THE NC ZONES SHOULD BECOME
UNDER THE INFLUENCE OF NE/LY FLOW AND LOWER TD/S MAKING FOR A MORE
STABLE ENVIRONMENT. THUS...POPS ARE THE HIGH END CHANCE AND
GENERALLY APPLIED ONLY TO THE SC/GA ZONES THIS AFTERNOON. SBCAPE
VALUES WILL BE MODERATE AND LLVL SHEAR LOW...WITH DECENT BULK
SHEAR...SO THE STAGE WILL BE SET ONCE MORE FOR SOME STRONG TO SEVERE
STORMS AGAIN THIS AFTERNOON. WITH THE FRONT STALLING OUT ACROSS THE
NRN UPSTATE...HIGHS TWILL RANGE FROM THE M70S ACROSS THE NRN NC
PIEDMONT TO THE L80S ACROSS THE LOWER UPSTATE. MTN VALLEYS WILL
REACH THE L70S.
A WEAK BUT NOTICEABLE SFC WEDGE BEGINS TO FORM LATE THIS AFTERNOON
AND EVENING. AT THE SAME TIME A DEEPENING SFC LOW WILL MOVE
NORTHEAST INTO THE LOWER MIDWEST AND THIS WILL PULL THE STATIONARY
FRONT OVER THE WEDGE. WITH GOOD MOISTURE...LIGHT TO MODERATE SHOWERS
SHOULD DEVELOP ACROSS THE NC ZONES AND THE ATMOS WILL BE TOO STABLE
FOR ANY REAL CONVECTIVE THREAT. WITH CLOUD COVER REMAINING FAIRLY
HIGH...LOWS WILL ONLY DROP INTO THE M50S TO AROUND 60 NON/MTNS AND
L50S MTN VALLEYS.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...THE SHORT RANGE REMAINS IN A STATE OF FLUX
BECAUSE OF UNCERTAINTY WITH THE PLACEMENT OF THE SURFACE BOUNDARY.
THE RELATIVELY FLAT UPPER FLOW ACROSS MUCH OF THE SOUTHEAST WILL
BUCKLE OVER TIME...WITH AN AMPLIFYING UPPER RIDGE...AS THE OMEGA
BLOCK TO OUR NORTH DISINTEGRATES SUNDAY AND INTO MONDAY. THERE DOES
NOT APPEAR TO BE MUCH IN THE WAY OF UPPER FORCING...BUT A SURFACE
BOUNDARY WILL PROVIDE LOW LEVEL FORCING AND FOCUS FOR CONVECTIVE
DEVELOPMENT...FIRST ON SATURDAY EARLY IN THE DAY AS IT MOVES
NORTHWARD AS A WARM FRONT. HAVE RAISED PRECIP CHANCES AND CLOUD
COVER A BIT OVER THE NORTHERN ZONES BASED ON THE SREF. A
CORRESPONDING DOWNWARD ADJUSTMENT TO MAX TEMPS WAS ALSO MADE. AFTER
A RELATIVELY QUIET SATURDAY NIGHT...THE FRONT IS EXPECTED TO BE
DRIVEN BACK SOUTHWARD BY THE NEXT SURFACE HIGH MOVING OVER THE
WESTERN GREAT LAKES...BUT PERHAPS NOT UNTIL LATE IN THE DAY. THE
MODEL GUIDANCE WAS ALL UNIFORMLY QUITE A BIT WARMER THAN THE
PREVIOUS FCST BECAUSE OF THE LATER TIMING...SO AN UPWARD ADJUSTMENT
OF ONE OR TWO CATEGORIES WAS MADE. THIS COULD EASILY GO WRONG AND BE
COOLER IF THE TIMING OF THE FRONT IS EARLIER THAN PLANNED. HAVE ALSO
RAISED MIN TEMPS SUNDAY NIGHT WITH INCREASED CLOUD COVER.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 340 AM FRIDAY...NOT MUCH IN THE LATEST OPERATIONAL MODELS IS
FOUND COMPELLING ENOUGH TO MAKE ANY SIGNIFICANT CHANGES TO THE
MEDIUM RANGE. AT LEAST THROUGH MID WEEK WE SHOULD BE UNDER THE
INFLUENCE OF UPPER RIDGING THAT WILL KEEP THE BEST UPPER FORCING TO
OUR NORTH...WITH THE WESTERN CAROLINAS ESSENTIALLY IN A WARM SECTOR.
THAT SHOULD FAVOR LOW CHANCES OF MAINLY DIURNAL CONVECTIVE PRECIP.
THE GFS DEVELOPS IN INTERESTING UPPER LOW LATE IN THE WEEK OVER THE
SOUTHEAST WHICH WOULD MEAN A BETTER CHANCE OF PRECIP...BUT THAT
FEATURE IS WELL OFFSHORE ON THE ECMWF...SO WE WILL NOT BITE ON IT.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AT KCLT...A TRICKY FCST FOR VSBY THIS MORNING. LOW TDD/S AND CALM
CONDS WILL MAKE AN MVFR BR POSSIBLE FOR THE FIRST COUPLE HRS OF THE
PERIOD. LEFT OUT OF TAF BASED ON 10SM OCCURRING RIGHT NOW AND THE
POTENTIAL FOR WINDS TO PICK UP A TAD AFT 12Z. AFTERNOON CONVECTION
LOOKS TO BE CLOSE TO THE TERMINAL. SHARP BOUNDARY JUST TO THE
SOUTH...WITH HRRR SHOWING STORMS RIDING ON AND TO THE N OF THE
BOUNDARY AND PERHAPS IMPINGING UPON THE AREA AROUND 20Z. WILL LEAVE
VCTS OUT OF THE TAF PER COORDINATION WITH CWSU. WARM FRONT MOVES
OVER WEDGE TONIGHT AND MVFR CIGS WILL BE POSSIBLE AFT 09Z AS WEDGE
BOUNDARY SHIFTS NE.
ELSEWHERE...TOUGH CALL ON THE MTN VSBY THIS MORNING WITH WINDS
PICKING UP AND THEN SETTLING DOWN. WILL KEEP THE IFR MENTION AT KAVL
THROUGH 14Z. OTHER SITES...IT LOOKS LIKE VFR CIGS/VSBY THROUGH THE
MORNING WILL PREVAIL. EXPECT VCTS THIS AFTERNOON ACROSS THE NON/NC
SITES. STATIONARY FRONT WILL MOVE LITTLE AND MAKE FOR A GOOD AREA OF
CONVECTIVE DEVELOPMENT.
OUTLOOK...A FRONTAL BOUNDARY WILL REMAIN IN THE VICINITY OF THE AREA
THROUGH THE WEEKEND...RESULTING IN CONTINUATION OF UNSETTLED
WEATHER/PM SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS THROUGH THAT
TIME.
AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...
WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...DENSE FOG ADVISORY UNTIL 9 AM EDT THIS MORNING FOR NCZ053-064-
065.
SC...NONE.
&&
$$
SYNOPSIS...PM
NEAR TERM...SBK/LG
SHORT TERM...PM
LONG TERM...PM
AVIATION...SBK
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
650 AM CDT FRI APR 27 2012
.UPDATE...
12Z TAF DISCUSSION.
&&
.AVIATION...
COLD FRONT HAS PUSHED SOUTHWARD TO NEAR THE ALABAMA BORDER WITH
MUCH COOLER AND DRIER AIR NOW HAVING FILTERED BEHIND THE
BOUNDARY. LATEST HRRR AND 4 KM WRF INDICATE A FEW SHRA OR
POSSIBLY A TSRA WILL BE POSSIBLE AT AREA AIRPORTS IN THE 20-02Z
TIMEFRAME...BUT CONFIDENCE IS LOW. WILL MENTION VCSH DURING THE
LATE AFTERNOON/EARLY EVENING TIME PERIOD FOR NOW AND KEEP
CONDITIONS VFR AT CKV/BNA/CSV. WINDS WILL BE OUT OF THE NORTHEAST
THIS MORNING GRADUALLY VEERING TO SOUTHEASTERLY BY FRIDAY
NIGHT...WITH SPEEDS GENERALLY 10 KTS OR LESS.
&&
.PREV DISCUSSION... /ISSUED 355 AM CDT FRI APR 27 2012/
SHORT TERM (FRI-SUN)...
SFC HIGH PRES WL PREVAIL ACROSS THE OHVLY WITH PLENTY OF CLOUDS
AND COOLER TEMPS TDAY. MODELS DO A GOOD JOB KEEPING A STALLED
COLD FRONT NEAR THE AL-TN BORDER THIS AFTN. EXPECT HIGHS NEAR 70
DEGREES NORTH. SOUTHWEST FLOW ALOFT/DEEPER MOISTURE WL STREAM OVR
THE BOUNDARY THIS AFTN...WITH A CHANCE OF SHOWERS ACROSS THE
REGION.
TNGT...SFC LOW PRES IN THE SOUTHERN PLAINS WL DEVELOP NORTH INTO
MO TNGT. SYSTEM WL PUSH A WARM FRONT NORTH ACROSS MID TN TNGT...
WITH ONLY A FEW SHOWERS POSSIBLE NORTH.
SAT...WARMER TEMPS WITH WEAK H5 RIDGING EXPECTED. MANY LOCATIONS
EXPECTED TO HIT THE MID 80S. FOCUS FOR STORMS WL BE NORTH OF THE
AREA NEAR THE WARM FRONT IN KENTUCKY.
SAT NGT-SUN...SFC HIGH PRES IN THE GREAT LAKES MAY PUSH THE FNTL
BDRY BACK SOUTH INTO MID TN. ENSEMBLE MEAN GFS/EURO KEEP DEEPER
MOISTURE AND FRONTAL ZONE NORTH...WITH WEAK H5 RIDGING HOLDING ON
WITH DRY CONDITIONS SOUTH. WL ADVERTISE SCHC THUNDER POPS NORTH
MID TN.
LONG TERM (MON-THU)...
CONTINUED WARM MON. H5 RIDGE WEAKENS WITH AN INCREASE IN POPS MON
NGT-TUE. COULD BE SOME STRONG STORMS WITH MODEL SHOWALTERS TO -3.
UPPER RIDGE BUILDS BACK FOR A FEW DAYS W/POSSIBLE H5 CUTOFF LOW IN
SOUTHEASTERN STATES IN THE FAR EXTENDED AS PER GFS. WL NOT BUY
INTO A WET PERIOD AT THIS TIME. WL KEEP THE WARM PATTERN.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
55
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
741 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE LOW
WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE AREA.
DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST WISCONSIN...THUS
AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST TO SATURATE. OF
CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT. SOUNDINGS FROM BOTH
THE GFS AND NAM INDICATE THE POTENTIAL FOR THE COLUMN TO COOL
ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS NORTH OF
INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH ICE WILL BE
PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS INDICATE TO
BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH SURFACE
TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY SNOW THAT
DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE RAIN
COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC RAIN
CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR OUT AND
THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE ON THE
UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY THROUGH
THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO THE
REGION.
&&
.AVIATION...TODAY AND TONIGHT
618 AM CDT FRI APR 27 2012
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CENTRAL PLAINS AND INTO
SOUTHERN IOWA TONIGHT. LOOK FOR SHOWERS TO MOVE OVER KRST LATE
THIS AFTERNOON...WITH THE SHOWERS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS EVENING AND IMPACTING KLSE. PLAN ON CEILINGS
IN THE 8 TO 10 KFT RANGE AT THE TAF SITES THROUGH MUCH OF THE DAY
AS THE LOW APPROACHES THE REGION. CEILINGS WILL THEN LOWER INTO
THE MVFR CATEGORY AFTER MIDNIGHT TONIGHT WITH CLOUD BASES IN THE
1500 TO 2000 FT RANGE. LOOK FOR SOUTHEAST WINDS TO INCREASE INTO
THE 10 TO 17 KT RANGE TODAY WITH GUSTS AROUND 24 KTS POSSIBLE. THE
WINDS WILL BECOME EASTERLY TONIGHT AS THE LOW EDGES CLOSER.
FORECAST SOUNDINGS SUGGEST CEILINGS MAY LOWER INTO THE IFR
CATEGORY LATE TONIGHT INTO EARLY SATURDAY MORNING. DRY EASTERLY
FLOW NEAR THE SURFACE SHOULD KEEP CEILINGS IN THE MVFR CATEGORY
BUT WILL HAVE TO KEEP A CLOSE WATCH ON THIS. ALSO...THE RAIN MAY
MIX WITH OR CHANGE OVER TO SNOW AT TIMES TONIGHT INTO EARLY
SATURDAY MORNING. IF SNOW IMPACTS THE TAF SITES...VISIBILITIES
COULD BE REDUCED TO AROUND 2 MILES. WITH SURFACE TEMPERATURES WELL
ABOVE FREEZING...LITTLE OR NOW SNOW ACCUMULATION IS EXPECTED.
CONFIDENCE LOW ON PRECIPITATION SWITCHING OVER TO ALL SNOW SO HAVE
NOT INCLUDED IT IN THE FORECAST AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
740 AM CDT FRI APR 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
618 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE LOW
WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE AREA.
DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST WISCONSIN...THUS
AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST TO SATURATE. OF
CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT. SOUNDINGS FROM BOTH
THE GFS AND NAM INDICATE THE POTENTIAL FOR THE COLUMN TO COOL
ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS NORTH OF
INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH ICE WILL BE
PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS INDICATE TO
BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH SURFACE
TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY SNOW THAT
DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE RAIN
COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC RAIN
CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR OUT AND
THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE ON THE
UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY THROUGH
THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO THE
REGION.
&&
.AVIATION...TODAY AND TONIGHT
618 AM CDT FRI APR 27 2012
A LOW PRESSURE SYSTEM WILL MOVE ACROSS THE CENTRAL PLAINS AND INTO
SOUTHERN IOWA TONIGHT. LOOK FOR SHOWERS TO MOVE OVER KRST LATE
THIS AFTERNOON...WITH THE SHOWERS SPREADING EAST OF THE
MISSISSIPPI RIVER THIS EVENING AND IMPACTING KLSE. PLAN ON CEILINGS
IN THE 8 TO 10 KFT RANGE AT THE TAF SITES THROUGH MUCH OF THE DAY
AS THE LOW APPROACHES THE REGION. CEILINGS WILL THEN LOWER INTO
THE MVFR CATEGORY AFTER MIDNIGHT TONIGHT WITH CLOUD BASES IN THE
1500 TO 2000 FT RANGE. LOOK FOR SOUTHEAST WINDS TO INCREASE INTO
THE 10 TO 17 KT RANGE TODAY WITH GUSTS AROUND 24 KTS POSSIBLE. THE
WINDS WILL BECOME EASTERLY TONIGHT AS THE LOW EDGES CLOSER.
FORECAST SOUNDINGS SUGGEST CEILINGS MAY LOWER INTO THE IFR
CATEGORY LATE TONIGHT INTO EARLY SATURDAY MORNING. DRY EASTERLY
FLOW NEAR THE SURFACE SHOULD KEEP CEILINGS IN THE MVFR CATEGORY
BUT WILL HAVE TO KEEP A CLOSE WATCH ON THIS. ALSO...THE RAIN MAY
MIX WITH OR CHANGE OVER TO SNOW AT TIMES TONIGHT INTO EARLY
SATURDAY MORNING. IF SNOW IMPACTS THE TAF SITES...VISIBILITIES
COULD BE REDUCED TO AROUND 2 MILES. WITH SURFACE TEMPERATURES WELL
ABOVE FREEZING...LITTLE OR NOW SNOW ACCUMULATION IS EXPECTED.
CONFIDENCE LOW ON PRECIPITATION SWITCHING OVER TO ALL SNOW SO HAVE
NOT INCLUDED IT IN THE FORECAST AT THIS TIME.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 AM CDT FRI APR 27 2012
WI...FROST ADVISORY UNTIL 8 AM CDT THIS MORNING FOR WIZ032-033-041-
053>055-061.
FREEZE WARNING UNTIL 8 AM CDT THIS MORNING FOR WIZ017-029-034-
042>044.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM...RABERDING
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS DENVER CO
401 PM MDT FRI APR 27 2012
.SHORT TERM...UPPER LOW OVER NORTHERN KANSAS HEADING INTO SOUTHERN
NEBRASKA...WITH ANOTHER UPPER LOW OVER IDAHO AND WESTERN WYOMING.
FAIRLY TIGHT WEST TO NORTHWEST GRADIENT CURRENTLY OVER CFWA WITH
GUSTY WINDS MUCH OF AREA. ALSO SOME LINGERING MOISTURE ACROSS
MOUNTAINS WITH FLOW PRODUCING SOME WEAK OROGRAPHIC SNOW SHOWERS
ALONG CONTINENTAL DIVIDE. MODELS SHOW GRADIENT WEAKENING A BIT
DURING THE EVENING AS PLAINS SYSTEM GRADUALLY MOVES AWAY FROM
AREA. SO WINDS TO BE ON THE DECREASE...THOUGH MAY STILL A BIT
GUSTY OVER THE RIDGES AND FAR EASTERN PLAINS. LATEST RUC KEEPS
SOME MOISTURE IN PLACE OVER THE MOUNTAINS DURING THE EVENING...
WILL KEEP A FEW SHOWERS GOING FOR ZONES 31 AND 34. ON SATURDAY...
UPPER LOW PROGGED TO BE OVER WYOMING THROUGH THE DAY WITH WESTERLY
FLOW ALOFT OVER COLORADO. MODELS HINT AT MID LEVEL SHORTWAVE
ROTATING SOUTHEAST ON BACK SIDE OF THE LOW...WITH SOME INCREASE IN
MID LEVEL MOISTURE AND QG ASCENT OVER CFWA DURING THE AFTERNOON.
AT THE SURFACE...MODELS CONTINUE SHOW RETURN SOUTHERLY FLOW ACROSS
PLAINS BY AFTERNOON WITH SOME INCREASE IN LOW LEVEL MOISTURE. THE
INCREASE IN MOISTURE AND MID LEVEL ASCENT COMBINED WITH MODEST
LAPSE RATES SHOULD BE ENOUGH TO GENERATE SOME SHOWERS ACROSS THE
AREA DURING THE AFTERNOON. WILL MAINTAIN THE SLIGHT CHANCE POPS
FOR NOW AS ASCENT NOT THAT IMPRESSIVE. FORECAST CAPES MINIMAL...SO
NO THUNDER EXPECTED.
.LONG TERM...MODERATE WESTERLY FLOW ALOFT WILL CONTINUE OVER
COLORADO FOR MOST OF THE FORECAST PERIOD AS AN UPPER LOW IS
EXPECTED TO FORM OVER THE NORTHERN PLAINS AND THEN LINGER FOR A
FEW DAYS BEFORE MOVING INTO CANADA. THE LOW AMPLITUDE PATTERN MAY
WELL PERSIST THROUGH THE END OF NEXT WEEK. THIS PATTERN WILL
LIKELY BRING PERIODS OF MID-LEVEL MOISTURE ACROSS THE STATE FROM
THE WEST. THIS WILL KEEP THE CHANCE OF AFTERNOON AND EVENING
SHOWERS OVER THE HIGH COUNTRY. ON THE PLAINS...MSL PRESSURE FIELDS
SHOW THAT SOUTHERLY FLOW ACROSS THE PLAINS IS GOING TO BE FAIRLY
PERSISTENT THROUGH MOST OF THE WEEK. THIS IS GOING TO ALLOW
PERIODIC INTRUSIONS OF GULF MOISTURE ONTO THE EASTERN PLAINS. WEAK
SHORT WAVES EMBEDDED IN THE WESTERLY FLOW ALOFT WILL PROBABLY BE
SUFFICIENT TO GENERATE ROUNDS OF AFTERNOON AND EVENING SHOWER
ACTIVITY ON THE PLAINS EACH DAY. MOS TEMPERATURE GUIDANCE SHOWS
VALUES ON THE PLAINS ABOUT 10 TO 15 DEGREES ABOVE NORMAL THROUGH
THE WEEK. SO WARM TEMPERATURES AND A SLIGHT CHANCE OF SHOWERS WILL
BE THE FORECAST FOR MOST OF THE WEEK.
&&
.AVIATION...FAIRLY TIGHT SURFACE GRADIENT ACROSS PLAINS WITH GUSTY
NORTHWEST WINDS AT AREA AIRPORTS. MODELS SHOW GRADIENT WEAKENING
AFTER 03Z...SHOULD SEE WINDS DECREASE BUT MAY REMAIN NORTHERLY
OVERNIGHT. MODELS SHOW SOUTHEAST WINDS DEVELOPING ACROSS PLAINS
BY 18Z...BUT INDICATE SOME SORT OF DENVER CYCLONE IN THE AREA.
EVENTUAL LOCATION TO AFFECT WIND DIRECTION. WILL KEEP SOME SORT OF
A NORTHERLY COMPONENT FOR NOW.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....DANKERS
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER CO
1038 AM MDT FRI APR 27 2012
.UPDATE...STILL SOME LINGERING SHOWERS ACROSS FAR EASTERN
PLAINS...SHOULD BE EXITING THE AREA AS UPPER LOW HEADS EAST INTO
CENTRAL PLAINS. ALSO SOME SNOW SHOWERS OVER HIGHER MOUNTAINS.
THESE TOO SHOULD BE DISSIPATING SHORTLY AS DRIER SUBSIDENT AIR
MOVES OVER AREA. MAIN CONCERN STILL FOR GUSTY WINDS ACROSS PLAINS
AND HIGHER MOUNTAINS THROUGH THE AFTERNOON...THOUGH LATEST MODELS
SHOW GRADIENT DECREASING AS THE AFTERNOON PROGRESSES. EXPECT
SPEEDS TO STAY BELOW HIGH WIND CRITERIA. OVERALL CURRENT FORECASTS
STILL LOOK ON TRACK...MAY NEED TO BEEF THE PLAINS WINDS UP A BIT
FOR A FEW HOURS THIS AFTERNOON.
&&
.AVIATION...NORTHWEST WINDS SLOW TO MATERIALIZE...WITH SURFACE
ANALYSIS SHOWING A BIT OF AN ANTICYCLONE IN THE DENVER AREA. STILL
EXPECT THE NORTHWESTERLIES TO MATERIALIZE BY 18Z. WILL NEED TO
MAKE UPDATES TO DELAY THE GUSTY WINDS. STILL POTENTIAL FOR 25 KT
GUSTS THIS AFTERNOON. OVERALL...CURRENT TAF TRENDS LOOK ON TRACK
WITH VFR CONDITIONS THOUGH LATEST UPDATES TO INCLUDE 5000-6000
FEET CEILINGS FOR A FEW HOURS.
&&
.PREV DISCUSSION... /ISSUED 442 AM MDT FRI APR 27 2012/
SHORT TERM...700-500MB LOW CENTERED JUST SOUTH OF LIMON/SOUTHERN
LINCOLN COUNTY/ AT THIS HOUR ACCORDING TO RUC AND RADAR/SATELLITE
DATA. STRONG ISENTROPIC LIFT ON NORTH-EAST SIDE OF UPPER LOW WITH
A CONVEYOR BELT OF MOISTURE WRAPPING AROUND THE LOW CONTINUES TO
GENERATE NUMEROUS SHOWERS AND SCATTERED T-STORMS OVER MUCH OF
NORTHEAST COLORADO. SMALL STREAM FLOOD ADVISORY WAS ISSUED EARLIER
THIS MORNING FOR MUCH OF LINCOLN COUNTY WITH TRAINING STORMS
DROPPED 2-3 INCHES OF RAIN IN MATTER OF A FEW HOURS ACCORDING TO
RADAR. IN ADDITION HAVE WITNESSED NEW SHOWER/T-STORM DEVELOPMENT
IN THE PAST HOUR ALONG THE FRONT RANGE DUE IN LARGE PART TO A
CONVERGENCE OF DRIER NORTHWESTERLY FLOW OFF THE FRONT RANGE AND
MOIST EASTERLY FLOW ROUNDING THE TOP OF UPPER LOW. ONLY A MATTER
OF TIME FOR THIS NEW BATCH OF SHOWERS TO EITHER MOVE EAST OF THE
AREA OR JUST DISSIPATE WITH THE UPPER LOW CONTINUING TO MOVE EAST-
NORTHEAST AWAY FROM THE FRONT RANGE. HIGH PLAINS AIRMASS HAS
PRETTY BEEN WORK OVER WITH ONLY MARGINAL INSTABILITY SUSTAINING
CONVECTION. WITH THE UPPER LOW EXITING THE STATE MID TO LATE
MORNING...SO SHOULD MOST OF THIS PRECIPITATION...EXCEPT PERHAPS
IN THE FAR NORTHEAST CORNER OF THE STATE AND UP OF THE UPPER
RIDGES ALONG THE CONTINENTAL DIVIDE. CONSEQUENTLY...THE SEVERE
T-STORM WATCH FOR MUCH OF NERN COLORADO HAS BEEN ALLOWED TO
EXPIRE.
ATTENTION TURNS TO THE POSSIBILITY OF STRONG WINDS ON THE PLAINS
AND IN THE FRONT RANGE FOOTHILLS LATER THIS MORNING AND AFTERNOON
AS THE AREA COMES UNDER THE INFLUENCE OF MODERATE SUBSIDENCE AND
INCREASING POST-TROUGH NORTHWESTERLY FLOW ALOFT. CROSS SECTIONS
INDICATE CROSS MTN WIND SPEEDS OVER HIGHER ELEVATIONS OF THE FRONT
RANGE IN THE 40-50KT RANGE MID--MORNING THROUGH MID-AFTERNOON. ON
THE PLAINS...WINDS NOT AS STRONG...BUT NORTHEAST CORNER AND UP
ALONG THE WYOMING BORDER MODELS INDICATE WIND GUSTS IN THE
30-40KT RANGE DURING THE SAME PERIOD. PRESSURE GRADIENT IS
EXPECTED TO QUICKLY RELAX LATE THIS AFTERNOON RESULTING IN A RAPID
DROP OFF IN WIND SPEEDS BEFORE DARK. OTHERWISE AFTER THE SHOWERS
THIS MORNING...SHOULD SEE PLENTY OF SUNSHINE AND MUCH LOWER
HUMIDITY WITH TEMPERATURES SLIGHTLY ABOVE AVERAGE. TONIGHT...AREAS
WEST OF THE CONTINENTAL DIVIDE EXPECTED TO SEE A GRADUAL INCREASE
IN MID-LEVEL CLOUD COVER IN RESPONSE TO THE NEXT UPPER AIR TROUGH
TO DROPPING IN FROM THE NORTHWEST.
LONG TERM...THE UPPER LOW WILL REMAIN ANCHORED OVER WYOMING ON
SATURDAY BEFORE LIFTING INTO THE DAKOTAS ON SUNDAY. THIS WILL
LEAVE COLORADO IN A RELATIVELY DRY WESTERLY FLOW THROUGH THE
WEEKEND. HOWEVER THERE WILL BE SOME RETURN LOW LEVEL MOISTURE IN
DEVELOPING SOUTHEAST LOW LVL FLOW ALONG WITH A JET SEGMENT AND
WEAK WAVE LIFTING THROUGH SOUTHEAST COLORADO LATE SATURDAY NIGHT
AND SUNDAY. THIS WILL RESULT IN SOME SCATTERED SHOWER ACTIVITY
ACROSS THE EASTERN PLAINS. MONDAY LOOKS TO BE RATHER DRY EXCEPT
MAYBE A SLIGHT CHANCE OF LATE DAY SHOWERS. THE NEXT WAVE WILL
BRING A BIT OF AN INCREASE IN SHOWERS FOR LATE TUESDAY AND
WEDNESDAY BUT OVERALL MOISTURE AND INSTABILITY IS MARGINAL AND
WILL KEEP POPS IN THE SLIGHT CHANCE RANGE. TEMPERATURES WILL
GRADUALLY WARM TO ABOVE SEASONAL HIGHS BY EARLY NEXT WEEK.
AVIATION...LIFR CEILINGS AND VISIBILITY AT PRESENT TIME AT
DENVER AREA AIRPORTS EXPECTED TO RAPIDLY IMPROVE OVER THE NEXT 1-2
HOURS AS DRIER AIR MOVES DOWN FROM THE FRONT RANGE ON NORTHWEST
WINDS. CIGS AND VSBYS AT BJC SHOULD GO VFR BY 12Z AND NOT LONG
AFTER THAT AT DIA. AFTER THAT TIME...LOOK FOR NORTHWEST WINDS TO
INCREASE DURING THE LATE MORNING HOURS WITH POSSIBLE GUSTS IN THE
20-25KT RANGE BY MIDDAY..POSSIBLY STRONG NEAR THE FOOTHILLS. BY
LATE AFTERNOON...A WEAKENING OF THE PRESSURE GRADIENT WITH THE
UPPER LOW WELL EAST OF COLORADO...EXPECT TO SEE SFC WINDS TURN
NORTH-NORTHEAST FOR A TIME EARLY THIS EVENING BEFORE ASSUMING A
TYPICAL DRAINAGE WIND PATTERN AFTER 03Z. ALL THIS UNDER CLEAR TO
MOSTLY CLEAR SKIES.
HYDROLOGY...PRECIPITATION NEARLY OVER THE FRONT RANGE FOOTHILLS
WITH DRIER DOWNSLOPE FLOW SETTING UP FOR THE REMAINDER OF THE DAY.
COULD STILL SEE A BRIEF SHOWER MOVE OFF THE CONTINENTAL DIVIDE AND
OVER THE FOOTHILLS EARLY THIS MORNING AND DEPOSIT A FEW HUNDREDTHS
OF AN INCH OF RAIN. OTHERWISE NO ADDITIONAL PRECIPITATION
ANTICIPATED FOR THE BURN AREAS ALONG THE FRONT RANGE WITH THIS
STORM SYSTEM.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MIAMI FL
132 PM EDT FRI APR 27 2012
.AVIATION...
MAINLY VFR CONDITIONS WILL PREVAIL THROUGHOUT THE FORECAST PERIOD.
HIGH PRESSURE WILL CONTINUE TO MOVE OFF TO THE NORTHEAST AND
MOISTURE WILL INCREASE ACROSS THE REGION THROUGH SATURDAY. CLOUDS
WILL BEGIN TO LOWER AND THICKEN TONIGHT AND VCSH WILL BECOME
POSSIBLE AFTER 06Z ESPECIALLY ACROSS THE TERMINALS ALONG AND NEAR
THE SOUTHEAST FLORIDA COAST. WINDS WILL REMAIN EAST ACROSS THE
EAST COAST TERMINALS THIS AFTERNOON AND TONIGHT. AT KAPF A WEST
COAST SEABREEZE WILL DEVELOP LATER THIS AFTERNOON BEFORE
DIMINISHING EARLY THIS EVENING.
&&
.PREV DISCUSSION... /ISSUED 1021 AM EDT FRI APR 27 2012/
UPDATE...NO MAJOR CHANGES PLANNED FOR MORNING UPDATES WITH
CURRENT FCST SEEMING TO BE ON TRACK BASED ON CURRENT TRENDS. DEEP
TROPICAL MOISTURE NOT FAR TO OUR SE BUT THIS SHOULD REMAIN
OFFSHORE FOR MOST OF TODAY BEFORE BEING PULLED NORTH OVER THE
WEEKEND. THE 12Z MFL SOUNDING SHOWS VERY DRY CONTINUES ABOVE 5K
BUT THE LOWER LAYERS HAVE MOISTENED WITH PWAT INCREASING TO AN
INCH. THIS MAY BE ENOUGH TO SUPPORT A FEW SHRA LATE THIS AFTERNOON
AND IF FACT THE RAPID REFRESH HAS BEEN CONSISTENT THIS MORNING AND
SHOWING A FEW SHRA DEVELOPING OVER THE FAR SOUTH AND ALONG THE W
CST SEA BREEZE ACROSS INLAND COLLIER COUNTY. SO THAT IS THE ONLY
PLANNED CHANGE TO UP THE POPS TO SLIGHT CHANCE FOR THAT AREA INTO
THE EVENING.
KOB
PREV DISCUSSION... /ISSUED 647 AM EDT FRI APR 27 2012/
AVIATION...12Z ISSUANCE...PREVAILING VFR THROUGH THIS EVENING.
AS A SURFACE HIGH PRESSURE SYSTEM MOVES NORTHEAST AND MOISTURE
BEGINS TO INCREASE IN RESPONSE TO A DEVELOPING TROUGH OVER THE
CARIBBEAN, CLOUDINESS WILL GRADUALLY LOWER AND THICKEN THROUGH
THE PERIOD, ESPECIALLY AFTER 22Z. VCSH WILL ALSO BECOME POSSIBLE
AFTER 06Z, PARTICULARLY ALONG AND NEAR THE SOUTHEAST FLORIDA
COAST. WINDS WILL REMAIN EAST AROUND 10 KNOTS WITH SOME HIGHER
GUSTS, ESPECIALLY AFTER 18Z.
PREV DISCUSSION... /ISSUED 415 AM EDT FRI APR 27 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS EARLY THIS MORNING SHOWED A CLOSED
UPPER LOW OVER THE NORTHWEST CARIBBEAN...WITH A TROUGH AXIS
EXTENDING FROM THE LOW ACROSS SOUTH FLORIDA. AT THE
SURFACE...THE RIDGE AXIS WAS LOCATED ACROSS SOUTH CENTRAL
FLORIDA...TO THE NORTH OF LAKE OKEECHOBEE. THE SURFACE RIDGE WILL
SLOWLY MOVE TO THE NORTH THROUGH SATURDAY...AND BE LOCATED ACROSS
NORTH FLORIDA IN RESPONSE TO THE DEEP SOUTHERLY FLOW AND WARM
ADVECTION. A LIGHT SOUTHEAST FLOW WAS OCCURRING ALONG THE EAST
COAST EARLY THIS MORNING...WHERE TEMPERATURES REMAINED NEAR 70 TO
THE LOWER 70S.
WATER VAPOR SHOWED A LARGE MOISTURE SHIELD MOVING ACROSS THE BAHAMAS
AND ERODING THE DRY AIR THAT WAS LOCATED ACROSS THE REGION...AND
DEWPOINTS ARE EXPECTED TO STEADILY INCREASE TODAY. THE SOUNDING
FROM LAST NIGHT HAD A PWAT OF ONLY 0.45 INCHES...WHICH WAS 2
STANDARD DEVIATIONS BELOW NORMAL. BY SATURDAY MORNING...AT LEAST
THE SOUTHERN HALF OF THE REGION COULD SEE PWATS INCREASE TO
AROUND 2 STANDARD DEVIATIONS ABOVE NORMAL. THAT MOISTURE MAY STICK
AROUND ACROSS MOST OF THE REGION THROUGH AT LEAST THE MIDDLE OF
NEXT WEEK. SO SAY GOODBYE TO THE DRY AND PLEASANT CONDITIONS THAT
WERE OBSERVED OVER THE PAST FEW DAYS AS DEWPOINTS RISE INTO THE
60S TO AROUND 70 THROUGH THE ENTIRE FORECAST PERIOD.
THERE IS STILL A LOT OF UNCERTAINTY REGARDING RAINFALL THIS
WEEKEND THROUGH THE MIDDLE OF NEXT WEEK...ESPECIALLY TOWARDS THE
GULF COAST. MODELS CONTINUE TO DIVERGE SOMEWHAT WITH THE
EVOLUTION OF THE UPPER LEVEL TROUGH/UPPER LOW OVER THE NORTHWEST
CARIBBEAN AND THE PLACEMENT OF A SURFACE TROUGH THIS WEEKEND.
THERE WAS A WEAK SURFACE BOUNDARY ACROSS THE CARIBBEAN AND A
SURFACE TROUGH IS EXPECTED TO DEVELOP TO THE SOUTH AND EAST OF THE
REGION THIS WEEKEND. HOWEVER...MODELS DIFFER IN THE PLACEMENT OF
THIS LOW LEVEL TROUGH...BUT HAVE BEEN SHIFTING EAST OVER THE PAST
FEW RUNS AND THIS WOULD KEEP MOST OF THE RAINFALL TO THE EAST OF
SOUTH FLORIDA. THE 00Z RUN OF THE GFS MOVES THE UPPER LOW
NORTHEAST DIRECTLY OVER OR EVEN JUST TO THE EAST OF SOUTH FLORIDA
BY 12Z SUNDAY. THAT MODEL IS ALSO FURTHER EAST WITH THE LOW
LEVEL/SURFACE TROUGH...DEVELOPING IT WELL TO THE EAST OF THE
REGION IN THE BAHAMAS. THE GFS DOES STILL SEEMS TO BE SUFFERING
FROM CONVECTIVE FEEDBACK ISSUES. THE NAM IS SIMILAR TO THE GFS
WITH THE DEVELOPMENT OF THE SURFACE TROUGH...WELL TO THE EAST OF
SOUTH FLORIDA...AND KEEPING MOST RAINFALL TO THE EAST OF THE
REGION AS WELL. THE ECMWF HAS ALSO SHIFTED EAST WITH THE UPPER
LEVEL TROUGH FROM ITS PREVIOUS RUN...BUT BRINGS THE LOW LEVEL
TROUGH WESTWARD TO THE EAST COAST OF FLORIDA ON SUNDAY ALONG THE
SURFACE RIDGE. IF THIS SCENARIO PANS OUT...HEAVY RAINFALL IS
POSSIBLE ACROSS SOUTH FLORIDA SATURDAY NIGHT THROUGH MONDAY
ESPECIALLY FROM THE PALM BEACH/BROWARD COUNTY LINE SOUTHWARD
TOWARDS THE EAST COAST. REGARDLESS OF THE EVOLUTION OF THESE
FEATURES THIS WEEKEND...MUCH DEEPER MOISTURE IS EXPECTED ACROSS
SOUTH FLORIDA. SO AT LEAST SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED ACROSS THE AREA AND OVER THE LOCAL
WATERS THIS WEEKEND. THE HIGHEST CHANCE OF RAIN THROUGH THE
WEEKEND WILL BE ALONG THE SOUTHEAST COAST.
THE UPPER LEVEL TROUGH IS EXPECTED TO MEANDER AROUND SOUTH FLORIDA
THROUGH THE MIDDLE PART OF NEXT WEEK...WITH EASTERLY LOW LEVEL FLOW
AND MID/UPPER FLOW CHANGING BASED ON THE POSITION OF THE TROUGH.
HEAVY RAINFALL WILL REMAIN A POSSIBILITY AS MODEL PWATS ARE 1.8-2.1
INCHES AND THE DEEP EASTERLY FLOW CONTINUES.
A BLEND OF THE ECMWF AND GFS YIELDS AROUND 20 KNOTS OF EASTERLY
FLOW OVER THE ATLANTIC FROM SATURDAY NIGHT THROUGH MONDAY...AND
THE BEST CHANCES OF RAIN COULD ACTUALLY BE LATE AT NIGHT EACH
NIGHT FROM COASTAL CONVERGENCE...AS SHOWN BY THE ECMWF. SO AT
LEAST A CHANCE OF SHOWERS WILL CONTINUE THROUGH THIS PERIOD FOR
THE EAST COAST WITH A SLIGHT CHANCE ELSEWHERE. TEMPERATURES WILL
REMAIN TRICKY FROM SATURDAY THROUGH MOST OF THE PERIOD DUE TO
CLOUD COVER AND POSSIBLE RAINFALL. GUIDANCE FOR TEMPERATURES SEEM
A BIT HIGH...SUGGESTING TEMPERATURES IN THE MIDDLE TO UPPER 80S
ALONG THE EAST COAST WITH THE DEEP EASTERLY FLOW AND POSSIBLY
BREEZY TO WINDY CONDITIONS SUNDAY THROUGH WEDNESDAY. SO UNDERCUT
GUIDANCE BY 1-3 DEGREES FOR HIGH TEMPERATURES. OVERNIGHT LOWS WILL
BE MUGGY AND WARM THROUGH THE PERIOD...WITH TEMPERATURES EXPECTED
TO REMAIN IN THE LOW TO MID 70S ALONG THE COAST AND THE 60S
INLAND.
AVIATION...06Z ISSUANCE...PREVAILING VFR EXPECTED THROUGH AT
LEAST LATE FRIDAY AFTERNOON AS HIGH PRESSURE REMAINS EAST OF THE
FLORIDA PENINSULA. AS MOISTURE RETURNS, CLOUDINESS WILL INCREASE
AND GRADUALLY LOWER, ESPECIALLY AFTER 22Z. SHRA COULD BEGIN TO
AFFECT SOUTHEAST PORTIONS OF THE REGION AS EARLY AS FRIDAY
EVENING, BUT EXPECTED COVERAGE TOO LOW TO MENTION VCSH ATTM.
SURFACE WINDS WILL REMAIN EAST SOUTHEAST WITH SPEEDS AVERAGING 10
KNOTS. A FEW HIGHER GUSTS ALSO POSSIBLE.
MARINE...
MAINLY EASTERLY FLOW AROUND 10 KNOTS WILL PREVAIL ACROSS THE
REGIONAL GULF AND ATLANTIC WATERS THIS MORNING. LATE FRIDAY INTO
EARLY SATURDAY THE LOCAL PRESSURE GRADIENT WILL INCREASE AS A WEAK
TROUGH IS FORECAST IN THE VICINITY OF THE BAHAMAS WITH MAINLY
EASTERLY FLOW CONTINUING BUT INCREASING TO THE 15 TO 20 KNOT RANGE
OVER THE WEEKEND. LATER ON SUNDAY INTO MONDAY THE AFOREMENTIONED
TROUGH IS FORECAST TO DEEPEN ACROSS THE BAHAMAS WHICH WOULD
INCREASE THE PRESSURE GRADIENT AND WINDS ACROSS THE ATLANTIC
WATERS. THERE CONTINUES TO BE VARIABILITY IN THE LATEST SUITE OF
MODEL GUIDANCE ABOUT JUST HOW MUCH THE TROUGH DEEPENS SO THERE IS
SOME UNCERTAINTY ABOUT THE WIND FORECAST AND THE EXPECTED SEAS
SUNDAY INTO THE EARLY PART OF NEXT WEEK. WINDS IN EXCESS OF 20
KNOTS ARE POSSIBLE FOR SEVERAL DAYS BEGINNING SUNDAY. BUT WITH THE
UNCERTAINTIES INVOLVED THE WINDS WERE MAINLY CAPPED BELOW 20
KNOTS...CLOSE TO HPC GUIDANCE.
FOR THE ATLANTIC AND GULF STREAM WATER SEAS NEAR 2 FEET ARE
FORECAST THROUGH FRIDAY WITH SEAS TO NEAR 3 FEET FORECAST OVER THE
WEEKEND ALTHOUGH SEAS OF 4 TO 6 FEET MAY BE POSSIBLE IN THE WATERS
TO THE EAST OF SOUTHEAST FLORIDA. HOWEVER...BEAR IN MIND THE
UNCERTAINTIES IN THE FORECAST OUTLINED ABOVE.
FIRE WEATHER...
AFTER TODAY NO CONCERNS WITH CRITICALLY LOW RELATIVE HUMIDITIES AS
MOISTURE RETURN IS ON THE INCREASE. HOWEVER...MINIMUM RELATIVE
HUMIDITIES THIS AFTERNOON ARE EXPECTED TO BE BELOW 35 PERCENT FOR
SEVERAL HOURS ACROSS GLADES COUNTY. SO A RFD HAS BEEN ISSUED FOR
GLADES COUNTY. PORTIONS OF HENDRY COUNTY COULD ALSO GET NEAR
CRITICAL VALUES THIS AFTERNOON.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 74 82 72 83 / 10 40 30 30
FORT LAUDERDALE 73 83 71 83 / 30 50 50 40
MIAMI 73 82 70 83 / 40 50 50 40
NAPLES 67 87 69 87 / 10 30 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...55/CWC
AREA FORECAST DISCUSSION...UPDATED FOR AVIATION
NWS PEACHTREE CITY GA
128 PM EDT FRI APR 27 2012
.UPDATE...
/ISSUED AT 1021 AM EDT FRI APR 27 2012/
WEAK FRONT IN NORTH GEORGIA...SAGGING TOWARDS ATLANTA AREA...
INCREASING CLOUDS TODAY. FORECAST ON TRACK...SLIGHT TWEAKS TO
CLOUDS/SKY...TEMPERATURES...AND WINDS FOR TODAY BASED OFF CURRENTLY
OBSERVED TRENDS. THE FRONT...CURRENTLY EXTENDING FROM ABOUT
DAHLONEGA TO ROME...COULD SPARK SOME SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING AS IT CREEPS SOUTHWARD.
10/39
&&
.PREV DISCUSSION... /ISSUED 745 AM EDT FRI APR 27 2012/
SHORT TERM /TODAY THROUGH SATURDAY/...
WEAK NORTHWESTERLY FLOW ALOFT HELPED A WEAK SURFACE COLD FRONT
MOVE TO THE NORTHERN DOORSTEP OF GEORGIA...AND STALL THERE. THIS
WILL SERVE AS A FOCUS FOR AFTERNOON CONVECTION THIS AFTERNOON...
ALTHOUGH THERE IS GREAT MODEL DISPARITY REGARDING THE AREAL
COVERAGE AND ACCUMULATION. NAM AND SREF ARE FAR MORE AGGRESSIVE
WITH LATE AFTERNOON THUNDERSTORMS FOR NORTH GEORGIA...BUT
ECMWF...GFS AND HRRR HAVE FAR LESS COVERAGE AND LIGHTER
ACCUMULATIONS. WILL SIDE WITH THE LESS AGGRESSIVE SOLUTIONS FOR
NOW...BUT THIS WILL NEED TO BE WATCHED. EXPECTING WIDESPREAD
MORNING STRATUS WHICH WILL INHIBIT HEATING...SO LATER CONVECTIVE
INITIATION SEEMS REASONABLE. CENTRAL GEORGIA LOOKS LIKE IT WILL
ESCAPE THE PRECIP CHANCES FOR THE SHORT-TERM. MOS TEMPS LOOK
GOOD...SO WILL NOT STRAY FROM GUIDANCE.
27
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
EXTENDED BEGINS WITH RIDGING BUILDING IN ALOFT AND SURFACE HIGH
PRESSURE OVER THE WESTERN ATLANTIC RIDGING INTO THE SOUTHEAST. THE
MAIN FLOW...ALONG WITH WEAK EMBEDDED IMPULSES...REMAINS JUST TO OUR
NORTH ROUNDING THE TOP OF THE RIDGE. WITH INCREASING THICKNESSES
AND MOISTURE...THE GFS REALLY INCREASES TEMPS ON SUNDAY...
FORECASTING RECORD OR NEAR-RECORD HIGHS IN THE UPPER 80S AND LOWER
90S. THE NAM HOWEVER REMAINS 8-10 DEGREES COOLER AND IS SIMPLY NOT
AS STRONG WITH THE RIDGING ALOFT. THE ECMWF SEEMS TO SUPPORT THE
GFS/S SOLUTION...SO OVERALL HAVE TAKEN A BLEND TO AVOID A DRAMATIC
SWING FROM YESTERDAY/S FORECAST BUT HAVE LEANED TOWARD THE WARMER
GFS. THIS WARMING TREND CONTINUES INTO THE EARLY PART OF THE WEEK
WITH THE 00Z GFS MUCH WARMER THAN THE 12Z RUN YESTERDAY...AND
WARMER THAN THE ECMWF IS IMPLYING. HAVE AGAIN TAKEN A BLEND...
TRYING TO ACCOUNT FOR RUN-TO-RUN DIFFERENCES AND FACTORING IN THE
ECMWF SOLUTION. OVERALL THOUGH TEMPS REMAIN ABOVE NORMAL THROUGH
THE PERIOD.
AS FOR POPS...THE EXTENDED LOOKS MOSTLY DRY...THOUGH AS THE UPPER
RIDGE BEGINS TO BREAK DOWN BY MONDAY NIGHT MOISTURE WILL BE ABLE
TO WORK FIRST INTO NORTH GEORGIA AND THEN FURTHER SOUTH. POPS
REMAIN SLIGHT CHANCE AT BEST BUT WITH A TYPICAL SUMMERLIKE DIURNAL
TREND TO THE CONVECTIVE POTENTIAL. BOTH THE GFS AND ECMWF WANT TO
BRING MOISTURE FROM THE ATLANTIC OVER FLORIDA AND EVENTUALLY INTO
PARTS OF GEORGIA...WITH THE GFS FASTER AND MORE IMPRESSIVE WITH
THE MOISTURE AMOUNTS. OF COURSE...THE GFS IS LIKELY OVERDONE WITH
THIS BUT THE TRENDS WILL HAVE TO BE MONITORED THROUGH SUBSEQUENT
FORECASTS.
TDP
&&
.AVIATION...
18Z UPDATE...
WEAK FRONTAL BOUNDARY ACROSS NORTH GA WILL PROVIDE THE FOCUS FOR
SCATTERED AFTERNOON CONVECTION. THE FRONT AND ASSOCIATED CONVECTION
IS EXPECTED TO SAG SOUTH THROUGH THE AFTERNOON... WARRANTING A TEMPO
TSRA GROUP FOR ATLANTA AREA TAF SITES FROM 20-23Z. THE SHRA/TSRA
THREAT SHOULD PUSH EAST OF ATL BY 00Z SAT WITH SCT MID CLOUDS ON TAP
OVERNIGHT. MAY SEE SCT-BKN LOW CLOUDS (900 TO 1200 FEET) CREEP NORTH
TOWARD ATL BY 12-13Z SAT MORN...BUT MODELS DO NOT INDICATE THIS SO
WILL JUST MENTION SCT FOR NOW. INCREASED RIDGING ALOFT WILL WARRANT
NO MENTION OF CONVECTION ON SAT. SW WINDS 8-10KTS THIS AFTERNOON
WILL GO LIGHT AND MORE SOUTHERLY TONIGHT. SW WINDS 8-10KTS WILL
PREVAIL ON SAT.
//ATL CONFIDENCE...18Z UPDATE...
HIGH CONFIDENCE ON ALL ELEMENTS...EXCEPT MODERATE CONFIDENCE ON
AFTERNOON TSRA COVERAGE IN ATL AREA.
39
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 83 59 85 60 / 40 20 10 5
ATLANTA 81 62 84 63 / 30 10 10 5
BLAIRSVILLE 78 55 81 54 / 20 20 10 10
CARTERSVILLE 79 58 87 57 / 30 20 20 10
COLUMBUS 84 61 86 60 / 5 10 5 5
GAINESVILLE 81 61 85 61 / 40 20 10 10
MACON 85 58 86 58 / 20 5 5 5
ROME 83 59 87 58 / 30 20 20 10
PEACHTREE CITY 82 56 87 56 / 20 10 10 5
VIDALIA 86 64 88 64 / 10 5 5 5
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
305 PM MDT FRI APR 27 2012
.UPDATE...
ISSUED AT 303 PM MDT FRI APR 27 2012
WINDS FINALLY BEGINNING TO MIX TO THE SURFACE WEST OF CWA...WITH
UPSTREAM OBS SHOWING GUSTS 38-44KT. LATEST RUC MATCHES UP PRETTY
WELL WITH CURRENT GUSTS AND ACTUALLY SHOWS WINDS ALOFT WEAKENING AS
THEY MOVE SOUTHEAST TOWARDS OUR CWA. WITH THIS IN MIND CONFIDENCE
IN WARNING CRITERIA BEING MET HAS DECREASED SIGNIFICANTLY...SO
HIGH WIND WARNING WAS DOWNGRADED TO ADVISORY FOR WESTERN
LOCATIONS. EASTERN LOCATIONS UNDER CURRENT WIND ADVISORY HAVE YET
TO CLEAR OUT...SO IM HESITANT TO CANCEL THE ADVISORY FOR THOSE
LOCATIONS DESPITE WINDS HOLDING IN THE 10-20KT RANGE. WILL
CONTINUE TO LET SUBSEQUENT SHIFTS MONITOR.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 236 PM MDT FRI APR 27 2012
THERE WILL BE A POSSIBILITY FOR SHOWERS EARLY THIS EVENING ACROSS
MAINLY THE EASTERN PORTION OF THE AREA ASSOCIATED WITH A DEPARTING
LOW PRESSURE SYSTEM. WIND GUSTS WILL SUBSIDE QUICKLY THIS
EVENING...AND WINDS BETWEEN 10 AND 15 MPH ARE EXPECTED INTO
SATURDAY MORNING. NEEDED TO CONSIDER IF A FROST ADVISORY WOULD BE
NECESSARY OVERNIGHT...BUT GIVEN THE TREND IN THE MODELS TOWARD
SLIGHTLY WARMER TEMPERATURES AND WINDS ABOVE 10 MPH...HAVE NOT
ISSUED AN ADVISORY.
LARGE UPPER LOW WILL REMAIN IN PLACE OVER THE NORTHERN PLAINS
THROUGH SATURDAY NIGHT. A SERIES OF SHORTWAVE TROUGHS ARE EXPECTED
THE UPPER LEVEL PATTERN ACROSS THE CENTRAL PLAINS WILL TRANSITION TO
A WESTERLY ZONAL PATTER BY SUNDAY NIGHT AS THIS UPPER LOW SHIFTS
NORTH INTO SOUTHERN CANADA. THE RESULT WILL BE A VERY ACTIVE
PATTERN OVER OUR CWA AS WEAK SHORTWAVE TROUGHS CONTINUE TO PASS
WITHIN THE VICINITY OF OUR CWA. THE FIRST WAVE IS STILL EXPECTED TO
ARRIVE BY SATURDAY NIGHT...WITH MODELS CURRENTLY SLOWING DOWN THE
ARRIVAL OF LIFT/MOISTURE OVER WESTERN LOCATIONS SATURDAY AFTERNOON
UNTIL SATURDAY EVENING. I TRENDED POPS SATURDAY AFTERNOON BACK AND
ADJUSTED TIMING TO SHOW THE BEST CHANCE FOR RAIN SHOWERS OVERNIGHT
SATURDAY.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 236 PM MDT FRI APR 27 2012
SUNDAY-MONDAY...GUIDANCE IN GENERAL AGREEMENT ON TIMING/POSITION
OF LIFT/MOISTURE SHIFTING EAST THROUGH THE DAY SUNDAY...WITH WEAK
ENERGY LINGERING INTO SUNDAY NIGHT. I ADJUSTED POPS TO SHOW BETTER
CHANCES SUNDAY MORNING TRANSITIONING TO THE EAST BY THE AFTERNOON.
I KEPT BETTER CHANCES ACROSS SOUTHERN AND EASTERN LOCATIONS SUNDAY
NIGHT THROUGH MONDAY MORNING...WITH DECREASING CONFIDENCE ACROSS
THE NORTHERN PART OF THE CWA WHERE THERE IS INDICATION OF
SUBSIDENCE BUILDING IN FROM THE NORTH/NORTHWEST.
THE MAIN STORM TRACK SHIFTS NORTH BY MONDAY...HOWEVER GUIDANCE
CONTINUES TO SHOW WEAK ENERGY PASSING WITHIN THE VICINITY OF OUR
CWA. THERE IS LOT OF VARIABILITY IN MODEL QPF FIELD WITH THESE
FEATURES...WHICH IS NOT SURPRISING CONSIDERING THE FAST NATURE OF
THESE FEATURES AND THE DIFFICULTY GUIDANCE USUALLY HAS AT
RESOLVING THEM AT THIS RANGE. ONLY MINOR CHANGES WERE MADE TO
POP/WX FORECAST BEYOND MONDAY...WITH TOO MUCH UNCERTAINTY IN
TIMING/POSITION OF INDIVIDUAL SMALL SCALE FEATURES.
HIGH TEMPERATURES SATURDAY AND SUNDAY SHOULD REMAIN BELOW NORMAL FOR
MOST OF THE AREA WITH CLOUD COVER AND A COOLER AIRMASS LINGERING
ACROSS THE EASTERN HALF OF THE CWA. FOR NOW TEMPS IN THE LOW TO
UPPER 60S ARE ANTICIPATED SATURDAY. SUNDAY SHOULD BE COOLER WITH
PRECIP AND CLOUDY CONDITIONS LIKELY HOLDING TEMPS BELOW 60F FOR MUCH
OF THE CWA...POSSIBLY COOLER. A WARMING TREND BEGINS MONDAY AS
WESTERLY FLOW BEGINS MODERATING THE AIRMASS OVER THE CENTRAL PLAINS.
WHILE THERE IS UNCERTAINTY IN REGARDS TO SHORTWAVE PASSAGES
AFFECTING HIGH/LOW TEMPS...OVERALL PATTERN FAVORS ABOVE NORMAL
TEMPERATURES THROUGH THE EXTEND PERIODS...WITH HIGHS IN THE UPPER
70S/LOW 80S WEDNESDAY THROUGH FRIDAY. THIS MAY STILL BE TOO COOL IF
SKIES REMAIN CLEAR...AND H85 TEMPS ADVERTISED BY ECMWF VERIFY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1133 AM MDT FRI APR 27 2012
SUB-VFR CONDITIONS ARE EXPECTED EARLY THIS AFTERNOON NEAR AREAS OF
SHOWERS AND THUNDERSTORMS...FOLLOWED BY VFR CONDITIONS OVERNIGHT
AND INTO SATURDAY. STRONG NORTHWESTERLY WINDS WILL DEVELOP BEHIND
THE LOW...WITH KGLD SEEING STRONGER GUSTS THAN KMCK. WINDS WILL
DIMINISH EARLY THIS EVENING...AND SKIES WILL BE MOSTLY CLEAR
OVERNIGHT.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WIND ADVISORY UNTIL 6 PM MDT /7 PM CDT/ THIS EVENING FOR
KSZ001>003-013>015-027>029-041-042.
CO...WIND ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ090>092.
NE...WIND ADVISORY UNTIL 6 PM MDT /7 PM CDT/ THIS EVENING FOR
NEZ079>081.
&&
$$
UPDATE...DR
SHORT TERM...CJS/DR
LONG TERM...DR
AVIATION...CJS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
354 PM CDT FRI APR 27 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.DISCUSSION...
20Z SURFACE ANALYSIS SHOWS A DRYLINE MIXING EAST THROUGH CENTRAL KS
WITH A COUPLE MORE UPDRAFTS FORMING OUT ACROSS THE WARM SECTOR. THE
WARM FRONT IS A LITTLE DIFFICULT TO PIN DOWN SINCE THERE IS NOT A
DISTINCT CHANGE IN AIRMASS AT THE FRONTAL BOUNDARY. THE DEWPOINT
GRADIENT WOULD SUGGEST THE WARM FRONT MAY HAVE LIFTED AS FAR NORTH
AS CNK TO MHK TO BURLINGTON. PERHAPS THE BEST INDICATOR OF THE WARM
FRONTS LOCATION IS THE AREA OF ELEVATED RADAR RETURNS FROM NEAR
COUNCIL GROVE TO BURLINGTON. GIVEN THE RUC FORECAST OF 0 TO 6 KM
BULK SHEER ON THE ORDER OF 60 KTS AND 0 TO 1 KM SHEER AROUND 35 KTS
WITH IN THE WARM SECTOR...SUPERCELL THUNDERSTORMS ARE POSSIBLE AS
WELL AS THE POTENTIAL FOR A COUPLE TORNADOES. THE LIMITING FACTOR IS
THE WARM SECTOR IS VERY NARROW. STORM MOTION FOR A RIGHT MOVING
STORM IS NORTHEAST AROUND 40 KTS...ALMOST PERPENDICULAR TO THE WARM
FRONT. SO STORMS ARE LIKELY GOING TO MOVE NORTH INTO THE COOLER
BOUNDARY LAYER AIR FAIRLY QUICKLY. ANOTHER LIMITING FACTOR IS THE
AMOUNT OF INSTABILITY...WITH MIXED LAYER CAPES MAYBE REACHING 2000
J/KG. THERE WILL BE A NARROW CORRIDOR WHERE TORNADOES ARE MORE
LIKELY FROM NEAR ABILENE DOWN THROUGH EMPORIA AND PERHAPS JUST NORTH
OF THIS AREA. BECAUSE THE WARM FRONT IS NOT WELL DEFINED...IT WILL
BE DIFFICULT TO JUDGE HOW FAR NORTH A STORM HAS TO GO TO BECOME MORE
ELEVATED.
WOLTERS
LATEST WATER VAPOR IMAGERY SHOWING STRONG UPPER LOW OVER
NORTHWEST KS WHICH SHOULD CONTINUE TO LIFT NORTHEASTWARD INTO
EASTERN NEBRASKA THIS EVENING. AS IT DOES...IT SHOULD ALSO LIFT
CONVECTION RAPIDLY TO THE NORTH AND EAST OF THE CWA BEFORE
MIDNIGHT...OR FURTHER AWAY FROM THE STRONGER INSTABILITY AXIS AS
DRIER AIR WRAPS IN BEHIND THE DRY LINE. THEREFORE DO NOT
ANTICIPATE SEVERE WEATHER THREAT ACROSS THE CWA BEYOND 9 OR 10 PM.
WILL THEN GO DRY ACROSS THE ENTIRE COUNTY WARNING AREA AFTER
MIDNIGHT.
BEYOND MIDNIGHT...FORECAST LOOKS DRY THROUGH THE DAYTIME ON SATURDAY
AS DEEPER MOISTURE AND INSTABILITY IS TEMPORARILY PUSHED SOUTH OF
THE CWA. WILL FAVOR THE COOLER HIGHS IN THE 60S TO THE NORTH OF I
70. HOWEVER...WARM AIR AND MOISTURE ADVECTION WILL DEVELOP ACROSS
THE CWA AHEAD OF THE NEXT SHORTWAVE TROUGH...SO HAVE LOW END POPS
SATURDAY NIGHT ACROSS THE SOUTHEAST FOR THUNDERSTORMS THEN INCREASE
POPS AND CLOUDS ON INTO SUNDAY AS WELL AS LOWERED HIGHS INTO THE LOW
TO MIDDLE 60S. SHORTWAVE TROUGH WILL MOVE INTO THE AREA SUNDAY
NIGHT/EARLY MONDAY WITH THE HIGHEST POPS STILL ALONG AND SOUTHEAST
OF THE TURNPIKE. SHOULD ALSO SEE HIGHER TEMPS AS THE LLVL FLOW
RETURNS TO SOUTHERLY. THEREFORE AFTER HIGHS NEAR 70 ON
MONDAY...SHOULD WARM INTO THE MIDDLE TO UPPER 70S.
WITH THE STRONGER WARM AIR ADVECTION HAVE CONTINUED CHANCE POPS INTO
TUESDAY AND EVEN WEDNESDAY AND THURSDAY AS A SERIES OF SHORTWAVE
TROUGHS ADVANCE NORTHEAST ACROSS THE CENTRAL PLAINS. HIGHS SHOULD
REMAIN WARM NEAR 80 ON INTO FRIDAY.
&&
.AVIATION...
LATEST GUIDANCE REMAINS CONSISTENT IN SHOWING THE MOST LIKELY TIMING
FOR CONVECTION BETWEEN 21Z AND 02Z. SO WILL CONTINUE A TEMPO GROUP
FOR THIS PERIOD. MVFR CIGS ARE ANTICIPATED TO REMAIN JUST WEST OF
TOP AND FOE UNTIL CONVECTION MOVES IN. BIGGEST UNCERTAINTY IS
WHETHER MVFR CIGS WILL MOVE BACK IN AS THE SFC LOW PASSES EAST
OVERNIGHT. THE GFS WANTS TO KEEP THEM NORTH OF THE TERMINALS. GIVEN
THE UNCERTAINTY WILL KEEP A VFR FORECAST FOR NOW WITH SCT025 ON THE
BACK SIDE OF THE LOW...BUT WILL NEED TO KEEP AN EYE ON THIS.
WOLTERS
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1216 PM CDT FRI APR 27 2012
...UPDATE TO AVIATION...
.UPDATE...
/ISSUED 1035 AM CDT FRI APR 27 2012/
THE SEVERE WEATHER THREAT CONTINUES FOR THIS AFTERNOON AND
EVENING...ESPECIALLY FOR AREAS ALONG THE U.S. 71 CORRIDOR IN
SOUTHEASTERN KANSAS AND WESTERN MISSOURI.
A STRONG SHORTWAVE CONTINUES TO PUSH EAST OVER WESTERN KANSAS LATE
THIS MORNING...WITH AN ASSOCIATED WELL DEVELOPED AREA OF LOW
PRESSURE AT THE SURFACE. AS OF 15Z...A WARM FRONT STRETCHED FROM
NEAR WICHITA TO MIAMI OK TO LITTLE ROCK.
THE WARM FRONT/WARM SECTOR OF THIS SYSTEM SHOULD BEGIN TO
OVERSPREAD THE WESTERN PORTIONS OF THE CWA THIS AFTERNOON...LIKELY
MIXING NORTHEAST TO ROUGHLY U.S. 65 BY 00Z. I DO HAVE SOME CONCERN
AS TO WHETHER MODEL GUIDANCE IS UNDER-PLAYING THE SPEED OF THE
WARM FRONT...AS A COMBINATION OF STRONG PRESSURE AND HEIGHT
FALLS...ALONG WITH A BIT OF OCCASIONAL SUNSHINE NORTH OF THE WARM
FRONT...COULD RESULT IN VERY RAPID NORTHWARD MOVEMENT LATE THIS
AFTERNOON.
WHILE THE WARM SECTOR IS CURRENTLY QUITE CAPPED PER 12Z
RAOBS...A SERIES OF VORT MAXES WRAPPING AROUND THE MAIN UPPER
LOW/SHORTWAVE WILL ACT TO ERODE MUCH OF THAT INHIBITION BY 21Z. AT
THE SAME TIME...AN APPROACHING...AND PERHAPS SURGING...DRYLINE AND
COLD FRONT WILL APPROACH EASTERN KANSAS...SERVING AS THE FOCUS FOR
THUNDERSTORM DEVELOPMENT BETWEEN 18Z AND 21Z WEST OF THE CWA.
CELLS WILL LIKELY MOVE INTO THE U.S. 71 CORRIDOR BETWEEN 21Z AND
23Z. 12Z NAM AND 12/13Z RUC CONTINUE TO SUPPORT SUPERCELLS...WITH
AN ASSOCIATED RISK OF VERY LARGE HAIL...STRONG WINDS...AND
TORNADOES. THE TORNADO THREAT APPEARS TO BE MAXIMIZED ACROSS
EASTERN KANSAS AND THE WESTERN TIER OR TWO OF COUNTIES IN
MISSOURI...EXTENDING SOUTH INTO NORTHEASTERN OKLAHOMA. WITH STRONG
THERMODYNAMIC AND KINEMATIC PARAMETERS IN PLACE...AN ISOLATED
STRONG TORNADO CAN NOT BE RULED OUT ACROSS THIS AREA.
STORMS WILL CONTINUE TO PUSH EAST THIS EVENING TOWARD THE U.S. 65
CORRIDOR...THOUGH THE EASTERN EXTENT OF THE SEVERE WEATHER THREAT
REMAINS DEPENDENT ON HOW FAR THE WARM SECTOR BUILDS INTO MISSOURI.
THE OVERALL SEVERE THREAT LATE TONIGHT SHOULD BE MITIGATED A BIT
BY A COOLING/INCREASINGLY INHIBITED BOUNDARY LAYER...THOUGH
ISOLATED SEVERE STORMS WILL BE POSSIBLE THROUGH MIDNIGHT.
BOXELL
&&
.DISCUSSION...
MAIN CONCERNS FOR THE FORECAST PACKAGE FOCUS ON THE POTENTIAL FOR
SEVERE THUNDERSTORMS THIS AFTERNOON INTO THIS EVENING.
EARLY MORNING CONDITIONS ACROSS THE OZARKS AND SOUTHEASTERN
KANSAS HAVE DEWPOINTS IN THE 50S WITH TEMPERATURES IN THE 60S
NORTH OF A FRONT LAID OUT ACROSS CENTRAL ARKANSAS. THIS IS THE
COLD FRONT THAT MOVED THROUGH THE OZARKS YESTERDAY MORNING AND IT
WILL BEGIN TO MOVE ITS WAY NORTH AS A WARM FRONT TODAY AND BRING A
RETURN OF SOUTHERLY WINDS AND ADDITIONAL MOISTURE TO THE REGION.
THIS WILL BRING THE POTENTIAL FOR SEVERE WEATHER TO THE REGION
THIS AFTERNOON AND EVENING.
CURRENT SHORT TERM MODELS HAVE THE WARM FRONT LIFTING THROUGH THE
OZARKS THROUGH THE DAY TODAY AS SURFACE LOW PRESSURE NOW OVER
EASTERN COLORADO AND WESTERN KANSAS TRACKS EAST ACROSS THE PLAINS.
THIS WILL OCCUR IN RESPONSE TO THE UPPER LEVEL SHORT WAVE/CLOSED
LOW MOVING EAST. THE LEFT EXIT REGION OF A 250MB/500MB JET MAX WILL
BEGIN TO ROUND THE BEND OF THE UPPER TROUGH AND PROVIDE GOOD
DIFFLUENCE ALOFT. THIS WILL BE OCCURRING OVER A REGION OF
INCREASING INSTABILITY WITH MLCAPE VALUES VIA THE NAM UP TO AROUND
2000 J/KG...WITH 150 J/KG IN THE 0-3 KM LAYER. WHILE THE MODELS DO
TEND TO OVER DO THE LOW LEVEL CAPE...EVEN TAKING HALF OF THE
MODEL OUTPUT WOULD BE ENOUGH FOR SEVERE STORMS TO DEVELOP. THIS
WILL OCCUR IN CONJUNCTION WITH 0-3 KM BULK SHEAR AROUND 50-60
KTS AND 0-1 KM STORM RELATIVE HELICITY VALUES OVER 400M2/S2.
WOULD EXPECT THAT AREAS WEST OF HIGHWAY 65 IN GENERAL WILL HAVE
THE BEST CHANCES FOR SEVERE STORMS...WITH LARGE HAIL...DAMAGING
WINDS AND TORNADOES ALL POSSIBLE. WILL NEED TO MONITOR THE
PROGRESS OF THE WARM FRONT AND HOW CLOSE TO THE REGION THE DRY
LINE GETS TODAY.
AS THE UPPER LEVEL TROUGH LIFTS OUT OF THE REGION FRIDAY NIGHT A
SECONDARY SLOW MOVING CUTOFF LOW OVER THE NORTHERN PLAINS WILL AID
IN DEVELOPING A SLIGHTLY SOUTHWESTERLY UPPER LEVEL FLOW OVER THE
WESTERN CONUS THROUGH THE WEEKEND. THIS WILL NOT ONLY HELP TO KEEP
THE FRONT WANDERING ACROSS MISSOURI BEFORE THE UPPER LOW LIFTS
NORTH SUNDAY NIGHT...IT WILL CONTINUE TO BRING UPPER LEVEL
MOISTURE INTO THE REGION THROUGH EARLY NEXT WEEK. THIS WILL KEEP
CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE FORECAST FOR THE
WEEKEND AND INTO TUESDAY OF NEXT WEEK.
THE REGION MAY SEE A BRIEF RESPITE FOR THE MIDDLE OF NEXT WEEK
BEFORE ANOTHER FRONT ATTEMPTS TO PUSH THROUGH THE OZARKS. THE
FRONT THEN LOOKS TO GET HUNG UP ACROSS MISSOURI AS UPPER LEVEL
RIDGING ATTEMPTS TO BUILD ACROSS THE SOUTHWESTERN CONUS FOR LATE
NEXT WEEK...RETURNING NORTHWEST UPPER FLOW OVER THE OZARKS.
HATCH
&&
.AVIATION...
/ISSUED 1209 PM CDT FRI APR 27 2012/
ACTIVE WEATHER WILL IMPACT AREA TERMINALS THIS AFTERNOON INTO
TONIGHT AS A WARM FRONT LIFTS NORTH ACROSS THE OZARKS AND A STORM
SYSTEM APPROACHES FROM THE WEST. MVFR CEILINGS WILL IMPACT THE
TERMINALS AT TIMES THROUGH THIS EVENING. THUNDERSTORMS WILL
DEVELOP ACROSS SOUTHEAST KANSAS BY LATE THIS AFTERNOON THEN TRACK
EAST INTO THE OZARKS THIS EVENING. SOME OF THESE STORMS WILL BE
SEVERE.
GUSTY SOUTHEASTERLY WINDS WILL PERSIST AHEAD OF THE APPROACHING
FRONT WITH FREQUENT GUSTS OVER 25 KTS. MARGINAL LOW LEVEL WIND
SHEAR WILL BE POSSIBLE ESPECIALLY THIS EVENING. SURFACE WINDS WILL
SHIFT TO THE WEST LATE TONIGHT AS THE FRONT MOVES EAST ACROSS THE
REGION.
FOSTER
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
259 PM EDT FRI APR 27 2012
.SYNOPSIS...
THE COLD NORTHWEST FLOW WILL CONTINUE INTO THIS EVENING WITH
PERHAPS A LEFTOVER SPRINKLE OF FLURRY. CLEARING SKIES LATER
TONIGHT WILL ALLOW TEMPERATURES TO FALL INTO THE 20S. SATURDAY
WILL START OUT SUNNY UNDER HIGH PRESSURE BUT A LOW PRESSURE SYSTEM
MOVING TO OUR SOUTH MAY BRING SOME HIGH CLOUDS BACK INTO THE AREA
LATE IN THE DAY. THIS SYSTEM MAY BRING SOME LIGHT RAIN OR MIXED
PRECIPITATION SATURDAY NIGHT OVER NORTHEAST PENNSYLVANIA.
&&
.NEAR TERM /THROUGH TONIGHT/...
SO THE QUESTION FOR THE NEAR TERM IS THIS: HOW MUCH WILL WE CLR
OUT? AS USUAL...A DFCLT CALL WITH EARLIER RUNS SHWG CLRG BY THIS
AFTN. LATEST NAM FCST STEADFASTLY PREDICTS CLRG THIS EVE WHILE THE
RUC STUBBORNLY KEEPS CLDS OVER MUCH OF CNTRL NY THRU 12Z. CLRG
OVER WRN PA HAS STOPPED MAKING PROGRESS EWRD THIS AFTN. WILL HEDGE
TWRD THE CDY RUC FOR THIS EVE...BUT FCST CLRG LTR IN THE EVE. THIS
WLD NRMLY PRESENT PROBLEMS FOR THE FREEZE ADVISORY WITH THE CLDS
LIMITING THE TEMP FALLS. HWVR...WE JUST NOW HAVE FNLY RISEN ABV
FRZG HERE AT BGM SO IT/S NOT LIKE WE HAVE ALL THAT FAR TO FALL.
WILL CONT WITH THE WARNING. ONLY OTR WX ISSUE IS THE LGT SHWRS OF
RAIN AND SNOW OVER NY. RADAR TREND SHOWS A SLOW WEAKENING OF THE
PCPN SO WILL CONT THE TREND WHILE KEEPING LGT PCPN FOR THE NEXT
FEW HRS...WITHDRAWING THE PCPN AREA TO THE NORTH.
&&
.SHORT TERM /SATURDAY THROUGH MONDAY/...
SFC HIPRES NOSES IN SAT AND BRIGS MAINLY CLR SKIES AND ALLOWS FOR
A RECOVERY ON TEMPS BEFORE HI CLDS RETURN FROM THE SOUTH LATE IN
THE DAY.
MODELS COMING INTO AGREEMENT ON THE WV PASSING SOUTH OF THE AREA
LATE SAT AND EARLY SUN. NAM HAD JUMPED NWRD WITH THE WV AND PCPN
BUT HAS NOW RETREATED SWRD NEAR THE GFS SOLN. GFS IS A BIT FASTER
WITH THE PCPN BUT BOTH MODELS JUST BRUSH THE SRN ZONES MAINLY AFT
00Z SUN. PCPN TYPE ANALYSIS SUGGESTS RAIN TO START BUT A
TRANSITION OVER TO SOME LGT SNOW LATE AS THE TROF PASSES.
1028MB HI BLDS INTO THE LAKES BHD THE WV AND BRINGS COLD AND DRY
AIR FOR SUN AND MON. THIS WILL NO DOUBT RESULT IN VERY CHILLY
NGTS WITH MINS WELL DOWN INTO THE 20S AND RESULTING CONTINUENCE OF
THE FREEZE WARNING
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
11 AM UPDATE...
FOLLOWED HPC GUIDANCE. ZONAL FLOW WITH TWO SYSTEMS GOING THROUGH
DURING THE PERIOD. CHANCE OF RAIN SHOWERS EACH PERIOD WITH
TEMPERATURES SLIGHTLY ABOVE NORMAL.
MODELS SIMILAR. WEAK FIRST SYSTEM COMES IN LATE MONDAY NIGHT WITH
SHOWERS AND CONTINUES INTO TUESDAY NIGHT. TRACK OF THE SURFACE LOW
JUST TO THE SOUTH. MAY BE A BREAK WEDNESDAY BUT WILL BE BRIEF AS
SECOND LARGER AND STRONGER SYSTEM MOVES INTO THE MIDWEST WED. A
WARM FRONT PUSHES INTO THE AREA LATE WEDNESDAY. THIS SURFACE LOW
TRACKS SLOWLY ENE ACROSS THE WESTERN GREAT LAKES INTO SE CANADA
FRIDAY. MULTIPLE COLD FRONTS FRIDAY TO SATURDAY. AS USUAL THE GFS
IS SLIGHTLY FASTER BUT NOT THAT MUCH DIFFERENCE FOR DAY 7.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
18Z FRI UPDATE... MVFR RESTRICTIONS ARE LIKELY TO CONTINUE AT
KITH/KBGM TIL LATE AFTN (20-22Z). OTHERWISE...VFR CIG BASES ARE
ANTICIPATED (3500-4500 FT AGL). DURG THE EVE (00-03Z)...DRIER AIR
SHOULD FINALLY WORK IN AT LOWER-LEVELS...LEADING TO CLEARING
SKIES. GUSTY NW WINDS THIS AFTN AND EARLY EVE...SHOULD DIMINISH TO
UNDER 10 KT BY 01-02Z.
SAT...VFR EXPECTED THROUGH 18Z...WITH NW WINDS ONLY 5-10 KT.
.OUTLOOK...
SAT...MAINLY VFR. A LOW PROBABILITY OF MVFR RESTRICTIONS AT KAVP
IN THE LATE AFTN/EARLY EVE PD.
SUN-MON...VFR.
TUE INTO WED...RESTRICTIONS POSSIBLE...AS SCTD -SHRA COULD DEVELOP.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM EDT SATURDAY
FOR PAZ038>040-043-044-047-048-072.
NY...FREEZE WARNING FROM 11 PM THIS EVENING TO 9 AM EDT SATURDAY
FOR NYZ009-015>018-022>025-036-037-044>046-055>057-062.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...MLJ
AREA FORECAST DISCUSSION
NWS RALEIGH NC
300 PM EDT FRI APR 27 2012
.SYNOPSIS...
A COLD FRONT WILL BECOME NEARLY STATIONARY OVER SOUTH CAROLINA THIS
AFTERNOON AND EVENING. THE FRONT IS THEN EXPECTED TO PUSH BACK
NORTHWARD AS A WARM FRONT SATURDAY.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 300 PM FRIDAY...
THE COLD FRONT HAS SETTLED TO NEAR THE NC/SC BORDER AS OF
MID-AFTERNOON. HIGH PRESSURE (1025+ MB) CONTINUED TO BUILD INTO
CENTRAL AND EASTERN NC FROM THE GREAT LAKES. THE POSITION OF THE
COLD FRONT WAS DEPICTED NICELY ON THE LATEST VISIBLE SATELLITE DATA
BY A CUMULUS FIELD. THIS CONVERGENCE ZONE WHERE CUMULUS WERE
DEVELOPING EXTENDED IN A WEST TO EAST FASHION FROM NEAR CHARLOTTE TO
FAYETTEVILLE TO NEW BERN. THE TEMPERATURES ALONG AND AHEAD OF THE
FRONT WERE GENERALLY IN THE LOWER 80S WITH DEW POINTS AROUND 60. IT
IS IN THIS REGION WHERE THE LATEST HI-RES MODELS WITH SUPPORT FROM
SEVERAL OPERATIONAL MODEL SOLUTIONS INDICATE THAT THERE WILL BE A
GOOD CHANCE OF SHOWERS AND POSSIBLY THUNDERSTORMS LATER THIS
AFTERNOON INTO THE EVENING HOURS.
STRONG HEATING WITH NEARLY FULL SUN (INTO THE LOWER 80S)...
AMPLE LOW LEVEL MOISTURE (DEW POINTS AROUND 60)... ALONG WITH THE
PRESENCE OF A WEAK MESO-LOW (CONVERGENCE)... AND UPPER SUPPORT
(COOLING ALOFT AND ASSOCIATED LIFT)... TRACKING ESE ALONG A BOUNDARY
(FOCUS)... ALL SUPPORT CONTINUED CONVECTIVE DEVELOPMENT. THE SEVERE
THREAT IS EXPECTED TO BE SOUTH OF THE CURRENT POSITION OF THE FRONT
WHICH WOULD PLACE ALMOST ALL OF NC OUTSIDE THE SEVERE RISK AREA. THE
LATEST HRRR SEEMS TO BE PICKING UP WELL ON THE CURRENT DEVELOPING
SCATTERED CONVECTION FROM NE GA INTO UPSTATE SC (ALONG A WEAK LOW
PRESSURE ASSOCIATED WITH THE FRONT). THIS MODEL SUGGESTS THAT
SCATTERED SHOWERS AND THUNDERSTORMS WILL DEVELOP EASTWARD OR
EAST-SOUTHEASTWARD ALONG THE BOUNDARY AIDED BY THE APPROACH OF A
WEAK WAVE ALOFT ACROSS ANSON... RICHMOND... HOKE... AND SCOTLAND
COUNTIES BY LATE AFTERNOON. THIS ACTIVITY SHOULD TRACK ESE AND
POSSIBLY AFFECT CUMBERLAND AND PORTIONS OF SAMPSON COUNTY BEFORE
SHIFTING WELL SOUTHEAST INTO SC AND OFFSHORE BY AROUND MID-EVENING.
THE STRONGER STORMS ARE EXPECTED TO BE CONFINED TO AREAS SOUTH OF
THE NC/SC BORDER.
TO THE NORTH... CONTINUED CAA/DAA SUPPORT CONTINUED STABILIZING OF
THE BOUNDARY LAYER WITH NIL POP EXPECTED. LATER TONIGHT... ALL AREAS
SHOULD BE PARTLY CLOUDY... BECOMING CLOUDY TOWARD DAYBREAK (SOUTH).
LOWS IN THE 45-50 RANGE EXPECTED NORTH... RANGING INTO THE MID 50S
SOUTH. THERE MAY BE SOME LIGHT RAIN AGAIN LATE ESPECIALLY SOUTH. WE
WILL INCLUDE LOW CHANCE POP AGAIN LATE FOR THAT POTENTIAL.
FOR SATURDAY... MODELS GENERALLY AGREE IN THAT THE FRONT OVER SC
WILL LIFT BACK NORTHWARD AS A WARM FRONT DURING THE LATE AFTERNOON
AND EVENING. LOW LEVEL MOISTURE WILL AGAIN BE ON THE INCREASE AS THE
DAY PROGRESSES AS A WARM AIR ADVECTION WIND PROFILE FLOW STRENGTHENS
FROM SW TO NE ACROSS THE REGION. MODELS GENERALLY DO NOT GENERATE
MUCH IN THE WAY OF RAINFALL SATURDAY WHICH SHOULD ALLOW THE WARM
FRONT FOR MORE OF AN EASIER/QUICKER TRACK OVER THE AREA. HOWEVER...
THE NAM MOS GUIDANCE (COOLER) APPEARS MORE REASONABLE GIVEN THE
EXPECTED INCREASE IN MOISTURE BETWEEN THE SURFACE AND 6-10K FEET AGL
ASSOCIATED WITH THE WAA. IT IS NOT UNTIL SATURDAY EVENING OR
OVERNIGHT IN WHICH THE SIGNIFICANT DRYING UP OF LOW TO MID LEVELS
SUPPORTS CLEARING. THIS OCCURS AS THE WARM FRONT LIFTS NORTH AND THE
LOW AND MID LEVEL FLOW BECOMES WESTERLY. EXPECT CLOUDY SKIES
SATURDAY WITH A LOW END POP FOR SOME LIGHT RAIN. QPF WILL BE LIGHT
(LESS THAN 0.10). HIGHS SHOULD END UP FROM THE MID 60S N-NE RANGING
INTO THE MID 70S FROM FAY TO LAURINBURG. -BADGETT
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
AS OF 300 PM FRIDAY...
SATURDAY NIGHT AND SUNDAY... THE WSW FLOW IN THE LOW AND MID LEVELS
WILL CONTINUE TO BRING DRYING AND WARMING. MODELS DISAGREE ON TIMING
OF ANOTHER COLD FRONT SUNDAY. IT APPEARS LIKELY THAT THERE WILL BE
LARGE SPREAD IN TEMPERATURES FROM SOUTHERN VA INTO NC SUNDAY
AFTERNOON. IT IS STILL TOO EARLY TO PIN THAT DOWN AT THE PRESENT
TIME. FOR NOW... EXPECT SUNDAY TO BRING SOME EARLY LINGERING CLOUDS
AND POSSIBLY FOG (ESPECIALLY N-E). THE SKIES SHOULD BECOME MOSTLY
SUNNY. AFTER MILDER LOWS IN THE MID 50S TO MID 60S N TO S... HIGHS
WILL SURGE WELL INTO THE 80S... LOWER TO MID 80S (NORTH) AND UPPER
80S SOUTH. THESE READINGS MAY FALL BACK INTO THE 70S (OR EVEN REMAIN
THERE IN THE NE ZONES) DEPENDING ON THE TIMING OF THE FRONT SUNDAY
AFTERNOON. REGARDLESS... THE WARMTH SUNDAY WILL BE SHORT LIVED AS
YET ANOTHER COLD FRONT WILL DIVE SE THROUGH THE REGION LATE SUNDAY
INTO SUNDAY NIGHT. THIS WILL BE DRIVEN SOUTHWARD BY A 1028+ MB HIGH
OVER THE GREAT LAKES BY 00Z/MON. THERE IS A CHANCE OF A FEW
THUNDERSTORMS SUNDAY AFTERNOON AND EVENING AS THE FRONT COMES INTO
THE REGION. -BADGETT
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 300 PM FRIDAY...
SUNDAY NIGHT AND MONDAY...THE MID LEVEL RIDGE OVER THE MISS RIVER
VALLEY WILL MOVE TO THE EASTERN SEABOARD...MEANWHILE HIGH PRESSURE
OVER THE GREAT LAKES AND NEW ENGLAND REGION WILL SHIFT ESE BECOMING
CENTERED OVER THE WESTERN ATLANTIC BY LATE MONDAY. THE COLD FRONT
WHICH WILL HAVE MOVED SOUTH ACROSS OUR CWA DURING THE DAYTIME SUNDAY
WILL SLOW DOWN OR BE STALLED JUST TO OUR SOUTH. IN THE PROCESS...LOW
LEVEL FLOW WILL BECOME NE BEHIND THE FRONT SUNDAY NIGHT...BUT THEN
SHIFT TO E MONDAY MORNING AND SE BY LATE MONDAY AS THE HIGH MOVES
ESE. FORECAST SOUNDINGS FOR 00Z-12Z MONDAY SHOW THAT WITH COOL LOW
LEVELS...LINGERING MOISTURE BETWEEN H7-H9...AND WEST FLOW ALOFT...
EXPECT STRATUS TO FORM OVERNIGHT AND LINGER INTO MONDAY MORNING.
LOWS WILL RANGE FROM AROUND 50 NORTH FARTHER BEHIND THE FRONT...TO
UPPER 50S SOUTH CLOSER TO THE FRONT. DURING THE DAYTIME MONDAY...THE
LOW LEVEL CLOUDS MAY BE TOUGH TO BREAK AS THE MID LEVELS CONTINUE TO
WARM AND STRENGTHENS THE INVERSION. DESPITE A MODEST LAYER OF LOW
LEVEL MOISTURE AND RESULTING CLOUDINESS...LIFTING MECHANISMS WILL BE
LIMITED THUS WILL KEEP POPS AOB 15 PERCENT MONDAY. CLOUDINESS WILL
HELP KEEP TEMP BELOW NORMAL...WITH HIGHS RANGING FROM THE MID 60S
NORTH TO LOWER 70S SOUTH.
FOR MONDAY NIGHT...LIGHT SE LOW LEVEL FLOW WILL CONTINUE...THUS
ADDITIONAL LOW STRATUS AND PERHAPS SOME FOG IS EXPECTED INTO TUESDAY
MORNING. WITH LOW CLOUDS AND SOUTHERLY COMPONENT TO THE LOW LEVEL
FLOW...TEMPS WILL REMAIN ABOVE NORMAL WITH LOWS GENERALLY IN THE
MID-UPR 50S.
THEN FOR THE MIDDLE OF THE WEEK (TUES-THURS)...EXPECT GENERALLY FAIR
WEATHER WITH LIMITED LIFTING MECHANISMS AS A BROAD RIDGE REMAINS
PARKED OVER THE SOUTHEAST AND THE BEST DYNAMICAL FORCING REMAIN TO
OUR NORTH. ALTHOUGH PWAT DURING THIS TIME WILL BE NEAR
CLIMATOLOGICAL NORMS...FORECAST SOUNDINGS ARE RELATIVELY DRY BETWEEN
550-850MB. FOR NOW WILL CONTINUE WITH POPS AOB 15 PERCENT.
PERSISTENT AND DEEP SW FLOW AND RESULTING THICKNESS VALUES SUGGEST
TEMPS SOME 5-10 DEGREE ABOVE NORMAL EACH DAY DURING THIS TIME...
HIGHS GENERALLY IN THE LOW 80S AND LOWS IN THE UPPER 50S.
FINALLY BY THURSDAY NIGHT AND FRIDAY...THE AFOREMENTIONED RIDGE WILL
FLATTEN AS A POTENT SHORTWAVE MOVES EASTWARD FROM THE ROCKIES.
ALTHOUGH THE LEE TROUGH SHARPENS ON FRIDAY AS WNW FLOW INCREASES...
MOISTURE IS PROGGED TO REMAIN LIMITED...SO RIGHT NOW MOST OF FRIDAY
LOOKS DRY...WITH BETTER RAIN CHANCES HOLDING OFF UNTIL LATE IN THE
DAY AS THE SHORT WAVE DIGS ACROSS THE REGION.
&&
.AVIATION /18Z FRIDAY THROUGH MONDAY/...
AS OF 300 PM FRIDAY...
VFR CONDITIONS EXPECTED THIS AFTERNOON AND EVENING AT ALL TAF SITES.
MVFR CIGS SHOULD DEVELOP NORTHWARD INTO THE KFAY AREA BY 12Z... THEN
REACH THE KRDU/KGSO TAF SITES. MVFR CIGS EXPECTED SATURDAY... BEFORE
LIFTING TO VFR SATURDAY NIGHT. VFR CONDITIONS EXPECTED SUNDAY...
BECOMING MVFR CIGS AGAIN LATE SUNDAY AND SUNDAY NIGHT.
OUTLOOK...GENERALLY MVFR CIGS SHOULD LIFT TO VFR BEFORE MONDAY...
VFR CONDITIONS EXPECTED MONDAY AND TUESDAY. PATCHY EARLY MORNING LOW
STRATUS/FOG MAY OCCUR MONDAY AND TUESDAY MORNINGS.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...BADGETT
LONG TERM...PETRO
AVIATION...BADGETT
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
338 PM CDT FRI APR 27 2012
.SHORT TERM...TONIGHT THROUGH MONDAY
338 PM CDT FRI APR 27 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION TYPE TONIGHT...THEN
PRECIPITATION CHANCES SUNDAY NIGHT INTO MONDAY.
LATEST WATER VAPOR SATELLITE IMAGERY INDICATING A COUPLE OF UPPER
LEVEL LOWS OVER THE NORTHERN ROCKIES AND THE CENTRAL HIGH PLAINS.
LATEST 19Z SURFACE ANALYSIS SHOWS LOW PRESSURE OVER WESTERN KANSAS
AND LATEST MOSAIC RADAR INDICATING SHOWERS AND THUNDERSTORMS WRAPPING
AROUND THE SURFACE LOW INTO PORTIONS OF SOUTH DAKOTA...NEBRASKA...
EASTERN KANSAS AND MISSOURI.
THE 27.12Z GFS/NAM ARE IN DECENT AGREEMENT IN LIFTING LOW PRESSURE
SYSTEM INTO THE UPPER MIDWEST AND GREAT LAKES REGION TONIGHT INTO
SATURDAY. THE DPROG/DT OF THE NAM/GFS DOES SHOW SURFACE/UPPER LEVEL
LOW A SLOWER PROGRESSION NORTHEASTWARD INTO THE GREAT LAKES REGION.
PLUS...WITH DRY AIRMASS IN PLACE OVER AREA PER 27.12Z UPPER AIR
SOUNDINGS. THIS WILL HAVE IMPACTS ON PRECIPITATION TIMING INTO THE
FORECAST AREA THIS EVENING. HAVE SLOWED BEGIN TIME AND REDUCED
PRECIPITATION CHANCES FROM WEST TO EAST ACROSS FORECAST AREA THIS
EVENING. THE DETERMINISTIC 27.12Z GFS/NAM INDICATE DECENT
ISENTROPIC LIFT AT 300K SURFACE AND DEEP QG FORCING IN
ASSOCIATION WITH SURFACE LOW MOVING INTO THE FORECAST AREA AFTER 06Z
SATURDAY. DEPENDING ON SATURATION OF ATMOSPHERE COLUMN...
PRECIPITATION WILL OVERSPREAD MUCH OF THE FORECAST AREA BY 06Z
SATURDAY. THE 27.15Z RUC AND 27.12Z NAM TIGHTEN PRESSURE GRADIENT
OUT AHEAD OF SURFACE LOW THIS EVENING OVER SOUTHEAST MINNESOTA AND
NORTHEAST IOWA. BOTH THE NAM AND RUC BUFKIT SOUNDINGS SHOW 25 TO
30 KNOTS MEAN ABSOLUTE MOMENTUM TRANSFER AT RST AND MCW. THE
WIND PRONE AREAS OF NORTHEAST IOWA AND SOUTHEAST MINNESOTA WILL
APPROACH SUSTAINED WIND SPEEDS OF 30 MPH AND WILL ISSUE A WIND
ADVISORY FOR THIS AREA THROUGH 03Z SATURDAY. NEXT CONCERN IS
POTENTIAL SNOW MIXING IN WITH THE RAIN AFTER 06Z SATURDAY. THE 27.12Z
GFS/NAM BUFKIT SOUNDINGS ARE STILL INDICATING ATMOSPHERE COLUMN NEAR
OR AT ZERO DEGREES CELSIUS OVER PORTIONS OF THE FORECAST AREA FROM
09Z TO 12Z SATURDAY. FOR NOW WILL CONTINUE MENTION OF RAIN/SNOW MIX
OVER MUCH OF THE FORECAST AREA FROM 09Z TO 15Z SATURDAY.
SURFACE LOW PUSHES EAST OF FORECAST AREA SUNDAY AND SURFACE RIDGE
OVER SOUTHERN ONTARIO BUILDS SOUTH INTO THE GREAT LAKES REGION.
PARTLY TO MOSTLY SUNNY SKIES...DRY WEATHER CONDITIONS AND NEAR
NORMAL TEMPERATURES CAN BE EXPECTED ACROSS THE FORECAST AREA.
FOCUS THEN TURNS TO SUNDAY NIGHT AND MONDAY...AS SURFACE RIDGE BUILDS
INTO THE NORTHEASTERN UNITED STATES. THE 27.12Z GFS/ECMWF/GEM SHOW
SOUTHERLY FLOW MOISTURE RETURN INTO THE FORECAST AREA...IN
ASSOCIATION WITH A WEAK LOW PRESSURE SYSTEM MOVING INTO THE CENTRAL
PLAINS. THE 27.12Z NAM IS MUCH FARTHER SOUTH THAN THE GFS/ECMWF/GEM
AND THE 27.12Z GFS/ECMWF/GEM INDICATE DECENT MOISTURE TRANSPORT AND
CONVERGENCE INTO THE FORECAST AREA AFTER 00Z MONDAY. CONFIDENCE IS
INCREASING ON PRECIPITATION CHANCES AND HAVE INCREASED
PRECIPITATION CHANCES MAINLY ACROSS THE SOUTHERN PORTIONS OF THE
FORECAST AREA. THE 27.12Z GFS SHOWS 100-200 J/KG OF 0-6KM MOST
UNSTABLE CAPE BETWEEN 00-12Z MONDAY MAINLY OVER SOUTHERN HALF OF
FORECAST AREA. AT THIS TIME...LEFT OUT ANY MENTION OF
THUNDERSTORMS...HOWEVER CANNOT RULE OUT AN ISOLATED THUNDERSTORM
SUNDAY NIGHT INTO MONDAY MORNING.
.LONG TERM...MONDAY NIGHT THROUGH FRIDAY
338 PM CDT FRI APR 27 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES THROUGH THE
FORECAST PERIOD. ALL THE DETERMINISTIC 27.12Z GFS/GEM/ECMWF ARE IN
GOOD AGREEMENT IN DEVELOPING WEST TO SOUTHWEST FLOW ALOFT THROUGH THE
PERIOD. MAIN DIFFERENCES BETWEEN THE MODELS IS TIMING THE EMBEDDED
SHORTWAVE TROUGHS IN THE WEST-SOUTHWESTERLY FLOW ALOFT INTO THE UPPER
GREAT LAKES REGION. CONFIDENCE IN TIMING OF SHORTWAVE TROUGHS INTO
THE REGION IS LOW...WILL CONTINUE WITH PRECIPITATION CHANCES
THROUGH THURSDAY. ALL THE DETERMINISTIC MODELS ARE IN DECENT
AGREEMENT ADVECTING LOW LEVEL WARM AIR INTO THE AREA MIDDLE OF NEXT
WEEK AND ALLOW FOR ABOVE NORMAL TEMPERATURES TUESDAY INTO THURSDAY.
&&
.AVIATION...
1130 AM CDT FRI APR 27 2012
CLOUDS WILL BE ON THE INCREASE TONIGHT...WITH LOWERING CIGS BETWEEN
09-12Z. -RA WILL FOLLOW WITH THE LIKELY MVFR/IFR CIGS...AND PROBABLY
SOME VSBY RESTRICTIONS. COLD AIR A LOFT COULD RESULT IN SOME -SN
MIXING IN WITH THE -RA BETWEEN 09-15Z...PER LATEST SOUNDINGS. BETTER
CHANCES AT KRST...AND WILL ADD SOME -RASN MIX OVERNIGHT. DON/T
EXPECT ANY -SN ACCUMULATIONS THOUGH. IF IT CHANGES OVER TO ALL SNOW
FOR A SHORT PERIOD...VSBYS WILL LIKELY BE REDUCED TO 2SM.
PCPN WILL LINGER THROUGH MUCH OF SAT AS AN UPPER LEVEL SHORTWAVE
TROUGH SPINS ACROSS THE REGION...AND EXPECT A CONTINUATION OF THE
MVFR/IFR CONDITIONS THROUGH THE DAY. PCPN SHOULD DIMINISH AFTER 00Z
AS THE SHORTWAVE EXITS AND HIGH PRESSURE FROM THE NORTHEAST EXERTS
SOME INFLUENCE. THE LOW CIGS COULD HANG ON MOST OF THE
NIGHT...ESPECIALLY FOR KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
338 PM CDT FRI APR 27 2012
WI...NONE.
MN...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR MNZ086-087-094-
095.
IA...WIND ADVISORY UNTIL 10 PM CDT THIS EVENING FOR IAZ008>010-018-
019-029-030.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1130 AM CDT FRI APR 27 2012
.SHORT TERM...
315 AM CDT FRI APR 27 2012
MAIN FORECAST CONCERN IS ON PRECIPITATION CHANCES TONIGHT THROUGH
SATURDAY NIGHT WITH SOME PRECIPITATION TYPE CONCERNS AS WELL.
06Z SURFACE ANALYSIS SHOWS HIGH PRESSURE ANCHORED OVER NORTHERN
WISCONSIN AND UPPER MICHIGAN. MEANWHILE...WATER VAPOR IMAGERY SHOWS
A VIGOROUS SHORTWAVE ALONG THE NEW MEXICO/COLORADO BORDER...WITH A
PLUME OF 50 DEGREE DEW POINTS SURGING NORTHWARD AHEAD OF IT THROUGH
THE HIGH PLAINS. RUC SHOWING MOISTURE TRANSPORT EDGING INTO THE
WESTERN SECTIONS OF MINNESOTA AND IOWA...WHERE SHOWERS ARE OCCURRING.
27.00Z MODELS OFFER SIMILAR SOLUTIONS THROUGH THE PERIOD. IN THE
NEAR TERM...MOISTURE TRANSPORT WILL REMAIN WEST OF THE FORECAST AREA
THIS MORNING AS THE SHORTWAVE TROUGH ROTATES INTO KANSAS. DRIER
AIR FROM THE SURFACE HIGH WILL KEEP THE FORECAST AREA
PRECIPITATION FREE. HOWEVER...BY LATE THIS AFTERNOON THE SHORTWAVE
WILL TRACK INTO IOWA...WITH SATURATION OCCURRING OVER THE WESTERN
COUNTIES WHERE PRECIPITATION WILL MOVE INTO THE AREA.
AS WAVE ROTATES INTO WISCONSIN TONIGHT AND SURFACE LOW PASSES TO THE
SOUTH...850MB-500MB FRONTOGENESIS STRENGTHENS TO THE NORTH OF THE
LOW WITH PRECIPITATION OVERSPREADING MUCH OF THE REMAINDER OF THE
AREA. DRIER AIR FROM THE HIGH WILL REMAIN OVER NORTHEAST
WISCONSIN...THUS AREAS NORTHEAST OF INTERSTATE 94 WILL BE THE LAST
TO SATURATE. OF CONCERN ALSO IS PRECIPITATION TYPES LATE TONIGHT.
SOUNDINGS FROM BOTH THE GFS AND NAM INDICATE THE POTENTIAL FOR THE
COLUMN TO COOL ENOUGH TO SUPPORT SOME SNOW...ESPECIALLY IN AREAS
NORTH OF INTERSTATE 90. THE TWO UNCERTAINTIES TO THIS IS HOW MUCH
ICE WILL BE PRESENT...AND WARM LAYER TEMPERATURE...WHICH SOUNDINGS
INDICATE TO BE NEARLY ISOTHERMAL AROUND THE FREEZING MARK. WITH
SURFACE TEMPERATURES HOVERING IN THE 34 TO 37 DEGREE RANGE...ANY
SNOW THAT DOES MIX IN SHOULD NOT ACCUMULATE.
FRONTOGENETIC FORCING CONTINUES SATURDAY MORNING...BUT BEGINS TO
WEAK IN THE AFTERNOON. CATEGORICAL PROBABILITIES WARRANTED DURING
THIS TIME FRAME. PRECIPITATION WILL DECREASE SATURDAY NIGHT AS
FORCING WEAKENS AS HIGH PRESSURE BEGINS TO BUILD BACK INTO THE
REGION FROM THE NORTHEAST.
THIS HIGH WILL THEN PUSH IN FOR SUNDAY AND SUNDAY NIGHT WITH DRY
WEATHER EXPECTED. AN INCREASE IN MID AND HIGH LEVEL MOISTURE LOOKS
LIKELY LATER SUNDAY NIGHT AS NEXT WAVE BEGINS TO LIFT THROUGH THE
PLAINS AND THE HIGH BEGINS TO RETREAT EASTWARD.
TEMPERATURES LOOK QUITE COOL...ESPECIALLY FOR SATURDAY. WITH THE
RAIN COOLED AIR...READINGS WILL HAVE A HARD TIME MAKING IT PAST THE
MIDDLE 40S. OTHERWISE A SLIGHT WARMING TREND IS IN STORE FOR SUNDAY
AND MONDAY.
.LONG TERM...
315 AM CDT FRI APR 27 2012
ACTIVE FLOW PATTERN SETS UP FOR THIS PERIOD AS UPPER FLOW BECOMES
MORE SOUTHWESTERLY. DISTURBANCES IN THE FLOW WILL BRING PERIODIC
RAIN CHANCES TO THE AREA. DIFFICULT TO DISCERN SPECIFICS THIS FAR
OUT AND THUS WILL KEEP WITH CHANCES EACH DAY. TEMPERATURES WILL BE
ON THE UPSWING...WITH READINGS RISING TO ABOVE NORMAL FOR TUESDAY
THROUGH THURSDAY AS SOUTHERLY LOW LEVEL FLOW ADVECTS WARMER AIR INTO
THE REGION.
&&
.AVIATION...
1130 AM CDT FRI APR 27 2012
CLOUDS WILL BE ON THE INCREASE TONIGHT...WITH LOWERING CIGS BETWEEN
09-12Z. -RA WILL FOLLOW WITH THE LIKELY MVFR/IFR CIGS...AND PROBABLY
SOME VSBY RESTRICTIONS. COLD AIR A LOFT COULD RESULT IN SOME -SN
MIXING IN WITH THE -RA BETWEEN 09-15Z...PER LATEST SOUNDINGS. BETTER
CHANCES AT KRST...AND WILL ADD SOME -RASN MIX OVERNIGHT. DON/T
EXPECT ANY -SN ACCUMULATIONS THOUGH. IF IT CHANGES OVER TO ALL SNOW
FOR A SHORT PERIOD...VSBYS WILL LIKELY BE REDUCED TO 2SM.
PCPN WILL LINGER THROUGH MUCH OF SAT AS AN UPPER LEVEL SHORTWAVE
TROUGH SPINS ACROSS THE REGION...AND EXPECT A CONTINUATION OF THE
MVFR/IFR CONDITIONS THROUGH THE DAY. PCPN SHOULD DIMINISH AFTER 00Z
AS THE SHORTWAVE EXITS AND HIGH PRESSURE FROM THE NORTHEAST EXERTS
SOME INFLUENCE. THE LOW CIGS COULD HANG ON MOST OF THE
NIGHT...ESPECIALLY FOR KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
740 AM CDT FRI APR 27 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RABERDING
LONG TERM....RABERDING
AVIATION.....RIECK