Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/30/12
AREA FORECAST DISCUSSION
NWS DENVER CO
819 PM MDT SUN APR 29 2012
.UPDATE...HAVE PEELED THE POPS OFF THE GRIDS FOR ALL BUT ZONES
46>51 TONIGHT...AND LOWERED THE POPS THERE TO ISOLD AS WELL. THE
THUNDERSTORMS THAT DEVELOPED THIS EVENING APPEARS TO BE BEST
REPRESENTED BY THE HRRR AND HIRESW-ARW-WEST MDLS SO WILL FOLLOWED
THEIR OVERNIGHT TREND. THE WRF SIMULATED IR IMAGE LOOKED
REPRESENTATIVE AS WELL.
&&
.AVIATION...CURRENT TAFS LOOK ON TRACK SO LITTLE IF ANY
ADJUSTMENTS PLANNED IN THE UPCOMING TAFS.
&&
.PREV DISCUSSION... /ISSUED 315 PM MDT SUN APR 29 2012/
SHORT TERM...THIS AFTERNOON IS A TRANSITIONAL PERIOD BETWEEN THE
COOL AND MOIST CONDITIONS OF THE PAST COUPLE DAYS TO WARMER AND
DRIER WEATHER EXPECTED TOMORROW. SURFACE OBSERVATIONS IN THE
MOUNTAINS SHOW DEW POINTS IN THE LOWER TEENS WHILE THE PLAINS
CONTINUE WITH VALUES IN THE LOWER 30S. SHOWERS ARE BUILDING OVER
THE ELEVATED TERRAIN OF THE PALMER DIVIDE AND OVER THE FAR NORTHEAST
CORNER OF THE STATE. WELD AND MORGAN COUNTIES ARE REMAINING SHOWER
FREE DUE TO SOME COOLER TEMPERATURES RELATED TO SOME CLOUD COVER
EARLIERIN THE DAY. THE AIRMASS WILL REMAIN SLIGHTLY UNSTABLE
THROUGH THE REST OF THE AFTERNOON DUE TO SURFACE HEATING. A WEAK
SHORT WAVE IS ALSO HELPING TO PRODUCE THE SCATTERED SHOWERS WE HAVE
SEEN UP TO THIS POINT. SHOWERS SHOULD RAPIDLY DECREASE AS THE SUN
GOES DOWN. OVERNIGHT AND TOMORROW...DRIER AND WARMER AIR WILL
ADVECT OVER THE REGION FROM THE WEST AS MODERATE WESTERLY FLOW ALOFT
DOMINATES THE WEATHER PICTURE. WITH LESS MOISTURE IN THE AIR AND AN
ABSENCE OF ANY TRIGGERING MECHANISM ALOFT...SHOULD SEE MOSTLY SUNNY
SKIES ALL DAY WITH TEMPERATURES ON THE PLAINS CLIMBING INTO THE MID
70S. ANY SHOWERS THAT DEVELOP WILL BE EAST OF OUR FORECAST AREA.
LONG TERM...ZONAL FLOW IS PROGGED MONDAY NIGHT FOR THE FORECAST
AREA...THEN WEST-SOUTHWESTERLY ON TUESDAY. ON TUESDAY NIGHT...A
WEAK BROAD UPPER TROUGH MOVES ACROSS...WITH FAIRLY STRONG
SOUTHWESTERLY FLOW ALOFT IN THE EVENING...DECREASING AFTER
MIDNIGHT. FOR THE MOST PART...ZONAL FLOW IS PROGGED ON WEDNESDAY
AND WEDNESDAY NIGHT...WITH A WEAK WAVE TO MOVE ACROSS AROUND LATE
WEDNESDAY AFTERNOON/EARLY EVENING. THE QG VERTICAL VELOCITY FIELDS
HAVE BENIGN SYNOPTIC SCALE ENERGY PROGGED FOR THE FORECAST AREA
MONDAY NIGHT THROUGH WEDNESDAY NIGHT. YOU MIGHT BE ABLE TO FIND A
WEAK COUPLET AT SOME LEVEL IF YOU LOOK CLOSE ENOUGH LATE
WEDNESDAY/WEDNESDAY EVENING...BUT IT IS STILL PRETTY CONVOLUTED.
THE BOUNDARY LAYER FLOW FROM MONDAY NIGHT INTO WEDNESDAY MORNING
SHOULD BE DOMINATED BY DOWNSLOPING MUCH OF THE TIME. A WEAKER
GRADIENT IS PROGGED FOR THE REST OF WEDNESDAY AND WEDNESDAY NIGHT...
SO NORMAL DIURNAL TRENDS SHOULD PREVAIL. FOR MOISTURE... MONDAY
NIGHT IS FAIRLY DRY...THEN MODELS HAVE PRETTY SUBSTANTIAL MID AND
UPPER LEVEL MOISTURE LATER MONDAY NIGHT THROUGH TUESDAY. THE MID
AND UPPER LEVEL MOISTURE ONLY DECREASES A LITTLE THE REST OF TUESDAY
NIGHT AND WEDNESDAY. MOISTURE INCREASES A BIT IN THE LOWER LEVELS
LATER WEDNESDAY AND WEDNESDAY NIGHT. THE BOUNDARY LAYER DEW POINT
FIELDS...SHOW THE DRY LINE RIGHT OVER THE EASTERN BORDER MONDAY
EVENING...THEN IT PUSHES WELL EAST OF COLORADO BEFORE MIDNIGHT. DEW
POINT READINGS ARE MAINLY IN THE 20S F MONDAY NIGHT INTO MID DAY
WEDNESDAY. BY LATER WEDNESDAY AFTERNOON AND NIGHT...THE GFS AND NAM
SHOW 40S F OVER THE NORTHEAST CORNER...WITH 30S OVER THE REST OF THE
PLAINS. THERE IS A TINY BIT OF CAPE RIGHT ALONG THE NORTHEASTERN
BORDER MONDAY EVENING. THEN CAPE IS ABSENT UNTIL MID DAY
WEDNESDAY. THERE IS SOME CAPE OVER THE CWA WEDNESDAY AFTERNOON AND
EARLY EVENING...THE BEST OVER THE EASTERN TWO-THIRDS OF THE PLAINS.
THE QPF FIELDS HAVE NO MEASURABLE PRECIPITATION FOR THE CWA MONDAY
NIGHT THROUGH MID DAY TUESDAY. THEN A TAD IS PROGGED IN THE
MOUNTAINS TUESDAY AFTERNOON INTO MID DAY WEDNESDAY. BY WEDNESDAY
AFTERNOON AND EVENING...THE QPF FIELDS HAVE MEASURABLE PRECIPITATION
OVER MUCH OF THE CWA...WITH A TAD FOR THE PLAINS ONLY. FOR POPS...
WILL HAVE 10-30% IN THE MOUNTAINS TUESDAY AFTERNOON AND NIGHT. SAME
FOR WEDNESDAY AND WEDNESDAY NIGHT. WILL GO WITH 10-20% POPS OVER
THE PLAINS WEDNESDAY AND WEDNESDAY EVENING. FOR TEMPERATURES...
TUESDAY`S HIGHS ARE CLOSE TO MONDAY`S. WEDNESDAY`S HIGHS ARE 1-2 C
WARMER THAN TUESDAY`S. FOR THE LATER DAYS...THURSDAY THROUGH
SUNDAY...THE FLOW ALOFT IS ZONAL THURSDAY AND FRIDAY...THEN
SOUTHWESTERLY SATURDAY AND SUNDAY. TEMPERATURES STAY ABOVE SEASONAL
NORMALS...AND MOISTURE IS SPARSE.
AVIATION...A SLIGHT CHANCE OF A PASSING SHOWER WILL CONTINUE FOR A
FEW MORE HOURS...BUT THEN SKIES WILL BECOME MOSTLY CLEAR. WINDS OUT
OF THE NORTHEAST THIS AFTERNOON WILL TRANSITION TO SOUTHERLY LATER
THIS EVENING. GENERALLY SOUTHERLY WINDS ARE EXPECTED TO CONTINUE
MOST OF MONDAY ALSO.
HYDROLOGY...NO HYDROLOGIC IMPACTS TODAY OR TONIGHT.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....RJK
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS MIAMI FL
929 PM EDT SUN APR 29 2012
.UPDATE...WINDS ALONG THE ATLANTIC COAST ARE RUNNING A TAD
HIGHER THAN INHERITED FORECAST, SO INCREASED WINDS A BIT THERE.
VIRGINA KEY IS GUSTING TO 37 KT AND FOWEY ROCKS IS NOW SUSTAINED
AT 30 KT, BUT THESE SITES ARE A BIT ELEVATED. EVEN SO, HIGH-END
SMALL CRAFT ADVISORY CONDITIONS WILL BE OCCURRING OFF THE
BROWARD/MIAMI-DADE COAST OVERNIGHT.
THE SOLID RAIN SHIELD ACROSS SE FLORIDA AND THE ATLANTIC SURE
BROKE UP EARLIER THIS EVENING. WATER VAPOR IMAGERY SHOWS THAT
UPPER LEVEL DRY AIR HAS INFILTRATED INTO THE AREA FROM THE SOUTH
AS THE MID LEVEL LOW IS NOW BISECTING THE AREA WITH DRY AIR
WRAPPED INTO IT ON ITS WEST AND SOUTH SIDE. THE UPPER TROUGH AXIS
IS ALIGNED FROM NW TO SE ACROSS SOUTH FL. THIS HAS BROUGHT IN SOME
SUBSIDENCE ON ITS WEST SIDE. THE BIG QUESTION IS WHAT WILL BE THE
TREND OVERNIGHT. GIVEN RADAR TRENDS AND LACK OF APPRECIABLE
ENVIRONMENTAL CHANGES OVERNIGHT...THE CURRENT THINKING IS THAT
PERIODS OF SHOWERS WILL CONTINUE TO MOVE ONSHORE THE SE FL COAST
WITH JUST A SLIGHT CHANCE OF A THUNDERSTORM.
THE PWAT ON THE MIAMI EVENING SOUNDING IS AT 1.87 INCHES, OR 170%
ABOVE AVG AND IN THE 99TH PERCENTILE FOR THIS TIME OF THE YEAR.
SO WITH THAT SAID, SHOULD A BAND OF HEAVY SHOWERS
DEVELOP...LOCALIZED LOCALES COULD SEE HEAVY RAINFALL OVERNIGHT
WITH POTENTIAL FLOODING CONCERNS DEVELOPING. HOWEVER, THIS THREAT
DOES NOT LOOK AS HIGH AS EARLIER THOUGHT, THOUGH STILL POSSIBLE.
SO WILL KEEP THE FLOOD WATCH GOING. ALSO, THE HEAVY RAIN RISK MAY
INCREASE ON MONDAY. KEY WEST AND MIAMI RADAR IMAGERY SHOWS A
CLUSTER OF CONVECTION AND CYCLONIC FLOW SOME 70 NM SE OF MARATHON.
THIS IS AT 8-10K FT. RIGHT NOW NO SIGNS OF A SURFACE CIRCULATION.
THIS FEATURE ASSOCIATED WITH A TROUGH WILL MOVE WEST NORTHWEST
OVERNIGHT-MONDAY PLACING SOUTH FL IN A FAVORABLE ESE MOIST WIND
FLOW FOR POSSIBLE LOCALIZED HEAVY RAINS. /GREGORIA
&&
.PREV DISCUSSION... /ISSUED 720 PM EDT SUN APR 29 2012/
AVIATION...SFC TROF XTNDG FM UPR FLA STRAITS NE TO N BAHAMAS
SLOLY MOVG W AND JUST OFF OF THE SE FLA COAST AT 30/12Z. SYSTEM
CROSSES S FLA AND INTO GUF OF MEX BY 30/18Z. VRY MOIST EASTERLY
WND FLOW WL PERSIST ACRS THE AREA THRU PD. ATTM WDSPRD MVFR CIG
ACRS S FLA WITH AREAS OF -RA BUT VSBY VFR. AFT 06Z WDSPRD MVFR CIG
AND -RA CONTINUES BUT POCKETS OF EMBEDDED HVY SHWRS MAY PRODUCE
IFR CIG /VSBY AT TIMES. WILL PLACE TEMPO MVFR CIG/VSBY VALUES IN
TAFS AFT 06Z PENDING DEVELOPMENT. EASTERLY WINDS WL PERSIST ALL
TAF SITES AND ARE XPCTD TO INCRS.
PREV DISCUSSION... /ISSUED 225 PM EDT SUN APR 29 2012/
DISCUSSION...WATER VAPOR CONTINUES TO SHOW WELL DEFINED MID LEVEL
TROUGH OVER THE WESTERN CARIBBEAN EXTENDING NORTHEAST INTO THE FL
STRAITS. AT THE SFC, A BROAD TROUGH ALSO STRETCHES ACROSS ROUGHLY
THE SAME AREA WITH VISIBLE SATELLITE INDICATING BROAD CIRCULATION
AROUND THESE TWO FEATURES WITH A RICH PLUME OF TROPICAL MOISTURE
FEED ACROSS CUBA, FL STRAITS AND S FL. THE 12Z MFL SOUNDING
ALTHOUGH CONTAMINATED BY CONVECTION AT LAUNCH TIME SHOWS THE DEEP
EASTERLY FLOW.
LOOKING AT THE VERY SHORT TERM, THE HRRR WHICH HAS BEEN DOING
REMARKABLY WELL THE PAST COUPLE OF DAYS SHOWS A DECREASING TREND
THROUGH THIS AFTERNOON BUT THEN A REGENERATION OFF THE SE CST AFT
03Z THIS EVENING WHICH IS AT THE END OF ITS CURRENT FCST CYCLE. BOTH
THE GFS AND NAM PERSIST IN SHOWING A DEEPENING SFC TROUGH OVER THE FL
KEYS FROM LATE THIS AFTERNOON INTO THIS EVENING AND MOVING IT WEST
INTO THE SE GULF BY LATE MONDAY. THEY HAVE HOWEVER BOTH SCALED BACK
THE STRENGTH AND NO LONGER SHOW A CLOSED CIRCULATION SO WILL STICK
CLOSER TO THE NAM SPEEDS WHICH IS THE WEAKER OF THE TWO MODELS. THE
LONGER RANGE MODELS STILL DIVERGE AS TO THE EVOLUTION OF THESE
SYSTEMS THROUGH THE NEXT 24 TO 36 HOURS BUT ALL AGREE TO A CERTAIN
DEGREE THAT THE BAND OF MOISTURE WILL MOVE VERY LITTLE THROUGH
THIS TIME FRAME. RAINFALL ACCUMULATION IS ALSO TROUBLESOME WITH
THE NAM NOT SHOWING MUCH AFT 00Z THIS EVENING AND ALTHOUGH THERE
HAS BEEN SOME DECREASE IN THE OVERALL REFLECTIVITY FROM THE
REGIONAL RADARS, THE TROPICAL FEED WILL CONTINUE AND THUS THAT
SOLUTION SEEMS UNREALISTIC. THE GFS SEEMS TO BE SUFFERING FROM
CONVECTIVE FEEDBACK AS IT IS SHOWING A BULLS EYE 12 HOUR TOTAL
ENDING AT 18Z MONDAY OF IN EXCESS OF 8 INCHES ACROSS NORTHERN
MIAMI-DADE COUNTY. OF COURSE, GIVEN THESE HISTORIC PWAT ANOMALIES
FOR LATE APRIL THIS SOLUTION CANNOT BE TOTALLY RULED OUT HOWEVER
AND SOMEWHERE FROM BROWARD TO MIAMI- DADE COUNTIES MAY INDEED APPROACH
8 INCHES OR EVEN SLIGHTLY HIGHER BY LATE MONDAY WITH THE GREATEST
COASTAL CONVERGENCE LIKELY OCCURRING AT LOW LEVELS ALONG AND NEAR
THE SOUTHEAST COAST LATE TONIGHT THROUGH EARLY MONDAY. THE ECMWF
IS A MIDDLE OF THE ROAD APPROACH. SO WITH ALL OF THIS BEING SAID,
THE FLOOD WATCH WILL CONTINUE THROUGH MONDAY EVENING FOR THE EAST
COASTAL REGION.
HIGH PRESSURE WILL REMAIN TO THE NORTHEAST OVER THE WESTERN ATLANTIC
WITH THE PRESSURE GRADIENT REMAINING TIGHT SO STRONG COASTAL
CONVERGENCE MAY AGAIN SET UP MONDAY NIGHT INTO EARLY TUESDAY AS THE
HIGH MOISTURE REMAINS ACROSS THE AREA. THE ECMWF HAS COME MORE IN
LINE WITH THE GFS AND SHOWING THE DEEP MOISTURE REMAINING IN PLACE
THROUGH THE END OF THIS WEEK SO RAIN CHANCES WILL CONTINUE WITH THE
HIGHEST CHANCES FOR THE EAST COAST.
MARINE...DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL
MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 80 73 82 / 70 60 40 50
FORT LAUDERDALE 72 79 74 83 / 80 70 50 50
MIAMI 70 80 72 83 / 80 70 50 50
NAPLES 68 82 70 86 / 40 50 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH MONDAY EVENING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM BEACH.
HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR BISCAYNE BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
720 PM EDT SUN APR 29 2012
.AVIATION...SFC TROF XTNDG FM UPR FLA STRAITS NE TO N BAHAMAS
SLOLY MOVG W AND JUST OFF OF THE SE FLA COAST AT 30/12Z. SYSTEM
CROSSES S FLA AND INTO GUF OF MEX BY 30/18Z. VRY MOIST EASTERLY
WND FLOW WL PERSIST ACRS THE AREA THRU PD. ATTM WDSPRD MVFR CIG
ACRS S FLA WITH AREAS OF -RA BUT VSBY VFR. AFT 06Z WDSPRD MVFR CIG
AND -RA CONTINUES BUT POCKETS OF EMBEDDED HVY SHWRS MAY PRODUCE
IFR CIG /VSBY AT TIMES. WILL PLACE TEMPO MVFR CIG/VSBY VALUES IN
TAFS AFT 06Z PENDING DEVELOPMENT. EASTERLY WINDS WL PERSIST ALL
TAF SITES AND ARE XPCTD TO INCRS.
&&
.PREV DISCUSSION... /ISSUED 225 PM EDT SUN APR 29 2012/
DISCUSSION...WATER VAPOR CONTINUES TO SHOW WELL DEFINED MID LEVEL
TROUGH OVER THE WESTERN CARIBBEAN EXTENDING NORTHEAST INTO THE FL
STRAITS. AT THE SFC, A BROAD TROUGH ALSO STRETCHES ACROSS ROUGHLY
THE SAME AREA WITH VISIBLE SATELLITE INDICATING BROAD CIRCULATION
AROUND THESE TWO FEATURES WITH A RICH PLUME OF TROPICAL MOISTURE
FEED ACROSS CUBA, FL STRAITS AND S FL. THE 12Z MFL SOUNDING
ALTHOUGH CONTAMINATED BY CONVECTION AT LAUNCH TIME SHOWS THE DEEP
EASTERLY FLOW.
LOOKING AT THE VERY SHORT TERM, THE HRRR WHICH HAS BEEN DOING
REMARKABLY WELL THE PAST COUPLE OF DAYS SHOWS A DECREASING TREND
THROUGH THIS AFTERNOON BUT THEN A REGENERATION OFF THE SE CST AFT
03Z THIS EVENING WHICH IS AT THE END OF ITS CURRENT FCST CYCLE. BOTH
THE GFS AND NAM PERSIST IN SHOWING A DEEPENING SFC TROUGH OVER THE FL
KEYS FROM LATE THIS AFTERNOON INTO THIS EVENING AND MOVING IT WEST
INTO THE SE GULF BY LATE MONDAY. THEY HAVE HOWEVER BOTH SCALED BACK
THE STRENGTH AND NO LONGER SHOW A CLOSED CIRCULATION SO WILL STICK
CLOSER TO THE NAM SPEEDS WHICH IS THE WEAKER OF THE TWO MODELS. THE
LONGER RANGE MODELS STILL DIVERGE AS TO THE EVOLUTION OF THESE
SYSTEMS THROUGH THE NEXT 24 TO 36 HOURS BUT ALL AGREE TO A CERTAIN
DEGREE THAT THE BAND OF MOISTURE WILL MOVE VERY LITTLE THROUGH
THIS TIME FRAME. RAINFALL ACCUMULATION IS ALSO TROUBLESOME WITH
THE NAM NOT SHOWING MUCH AFT 00Z THIS EVENING AND ALTHOUGH THERE
HAS BEEN SOME DECREASE IN THE OVERALL REFLECTIVITY FROM THE
REGIONAL RADARS, THE TROPICAL FEED WILL CONTINUE AND THUS THAT
SOLUTION SEEMS UNREALISTIC. THE GFS SEEMS TO BE SUFFERING FROM
CONVECTIVE FEEDBACK AS IT IS SHOWING A BULLS EYE 12 HOUR TOTAL
ENDING AT 18Z MONDAY OF IN EXCESS OF 8 INCHES ACROSS NORTHERN
MIAMI-DADE COUNTY. OF COURSE, GIVEN THESE HISTORIC PWAT ANOMALIES
FOR LATE APRIL THIS SOLUTION CANNOT BE TOTALLY RULED OUT HOWEVER
AND SOMEWHERE FROM BROWARD TO MIAMI- DADE COUNTIES MAY INDEED APPROACH
8 INCHES OR EVEN SLIGHTLY HIGHER BY LATE MONDAY WITH THE GREATEST
COASTAL CONVERGENCE LIKELY OCCURRING AT LOW LEVELS ALONG AND NEAR
THE SOUTHEAST COAST LATE TONIGHT THROUGH EARLY MONDAY. THE ECMWF
IS A MIDDLE OF THE ROAD APPROACH. SO WITH ALL OF THIS BEING SAID,
THE FLOOD WATCH WILL CONTINUE THROUGH MONDAY EVENING FOR THE EAST
COASTAL REGION.
HIGH PRESSURE WILL REMAIN TO THE NORTHEAST OVER THE WESTERN ATLANTIC
WITH THE PRESSURE GRADIENT REMAINING TIGHT SO STRONG COASTAL
CONVERGENCE MAY AGAIN SET UP MONDAY NIGHT INTO EARLY TUESDAY AS THE
HIGH MOISTURE REMAINS ACROSS THE AREA. THE ECMWF HAS COME MORE IN
LINE WITH THE GFS AND SHOWING THE DEEP MOISTURE REMAINING IN PLACE
THROUGH THE END OF THIS WEEK SO RAIN CHANCES WILL CONTINUE WITH THE
HIGHEST CHANCES FOR THE EAST COAST.
MARINE...DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL
MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 80 73 82 / 60 60 40 50
FORT LAUDERDALE 72 79 74 83 / 80 70 50 50
MIAMI 70 80 72 83 / 80 70 50 50
NAPLES 68 82 70 86 / 40 50 30 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH MONDAY EVENING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM BEACH.
HIGH RIP CURRENT RISK THROUGH MONDAY AFTERNOON FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR BISCAYNE BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...15/JR
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
207 PM EDT SAT APR 28 2012
.SYNOPSIS...
18Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS NORTHERN STREAM FLOW
EXTENDING FROM OVER THE 4-CORNERS REGION EASTWARD TO THE TN/OH
VALLEYS AND THEN OFF THE MID-ATLANTIC SEABOARD. CLOSER TO HOME...OUR
FORECAST AREA IS WEDGED BETWEEN UPPER LEVEL RIDGING ALONG THE
NORTHERN GULF COAST...AND A DISTURBANCE SPINNING OVER THE YUCATAN
CHANNEL/FL STRAITS. WV IMAGERY CONTINUES TO SHOW THAT MID/UPPER
LEVEL MOISTURE IS ADVANCING NORTHWARD AHEAD OF THIS DISTURBANCE AND
RAPIDLY ERODING THE DRY AIR CURRENTLY OVER THE FORECAST AREA. THIS
ADVANCING MOISTURE CAN BE SEEN IN SOME SIGNIFICANT DIFFERENCES
BETWEEN THE 12Z SOUNDING PROFILES FROM TAMPA AND MIAMI. THE KTBW
SOUNDING STILL SHOWED A FAIRLY DRY COLUMN ABOVE THE BOUNDARY LAYER
WITH A PW UNDER 1". THE KMFL SOUNDING ON THE OTHER HAND WAS QUITE
MOIST THROUGH THE COLUMN WITH A PW APPROACHING 2". MODEL GUIDANCE IS
IN GOOD AGREEMENT IN THE CONTINUED EROSION OF THE DRY AIR OVER OUR
HEADS INTO THE EVENING HOURS...AND EXPECT OUR 00Z SOUNDING TO SHOW A
JUMP IN PW.
AT THE SURFACE...RIDGE AXIS EXTENDS FROM OFF THE SOUTHEAST COAST
WESTWARD ALONG THE I-10 CORRIDOR. GRADIENT IS STILL RATHER LIGHT
OVER OUR REGION IN CLOSE PROXIMITY TO THE RIDGE AXIS. THIS LIGHT
GRADIENT HAS ALLOWED THE DEVELOPMENT OF BOTH EAST COAST AND WEST
COAST SEA-BREEZE CIRCULATIONS.
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
REST OF TODAY/THIS EVENING...THE INCREASING DEEP LAYER MOISTURE AND
EVENTUAL SEA-BREEZE COLLISIONS SHOULD BE ENOUGH TO FORCE AT LEAST
ISOLATED/WDLY SCT CONVECTION LATER THIS AFTERNOON INTO THE EVENING
HOURS. IN FACT...ALL THE 12Z HI-RES CONVECTIVE ALLOWING MODELS
CONTINUE TO PRODUCE CONVECTION ALONG THE FL WEST COAST LATER TODAY
WITH THE EVENTUAL APPROACH OF THE EAST COAST SEA-BREEZE. SEEING THE
ORGANIZATION OF THE CU FIELD ALREADY IN PLACE...THIS SCENARIO SEEMS
REASONABLE AND WILL KEEP THE 20-30% POPS IN THE FORECAST FROM
PASCO/HERNANDO COUNTY SOUTHWARD. OVER OUR FAR NORTHERN/NATURE COAST
ZONES...KEPT THE POPS AT A SILENT 10% UNDERNEATH THE MORE PRONOUNCED
SUPPRESSION FROM THE UPPER RIDGE.
TONIGHT...ANY LINGERING EVENING STORMS WILL FADE WITH THE LOSS OF
DIURNAL HEATING AND SEA-BREEZE FOCUS WITHIN A FEW HOURS OF SUNSET.
THE REMAINDER OF THE NIGHT LOOKS QUIET WITH GENERALLY DRY CONDITIONS
AND SEASONABLE TEMPERATURES.
SUNDAY THROUGH MONDAY...
TRICKY AND SOMEWHAT STUBBORN PATTERN WILL PERSIST THROUGH THE PERIOD
WITH STACKED RIDGING HOLDING DOMINANCE OVER THE NORTHERN PORTION OF
THE STATE...AND AN UPPER DISTURBANCE AND ASSOCIATED SURFACE TROUGH
AFFECTING THE SOUTHERN PORTION OF THE PENINSULA. ALTHOUGH THE
STRENGTH OF THE SURFACE TROUGH CROSSING THROUGH THE FLORIDA STRAITS
IS SOMEWHAT IN QUESTION DURING THE PERIOD...THERE IS DECENT MODEL
AGREEMENT THAT THE BEST RAIN CHANCES WILL REMAIN SOUTH OF OUR ZONES.
FORT MYERS REGION IS RIGHT ON THE NORTHERN EDGE OF THE LOW LEVEL
FOCUS...SO HAVE KEPT THOSE FAR SOUTHERN ZONES IN A 20-30% RAIN
CHANCE THROUGH THE PERIOD. MOVING FURTHER NORTH FROM CHARLOTTE AND
LEE COUNTIES...AND IT APPEARS THE CHANCES FOR ANY ORGANIZED SHOWER
ACTIVITY FALLS OFF QUICKLY UNDERNEATH THE UPPER RIDGE. WITH THIS IN
MIND...GIVING THE MAJORITY OF THE FORECAST AREA A DRY FORECAST WITH
NEAR TO ABOVE NORMAL TEMPERATURES.
&&
.LONG TERM (MONDAY NIGHT THROUGH FRIDAY)...
THE PERIOD BEGINS WITH AN UPPER RIDGE OVER THE GULF COAST/SE U.S.
AND A TROUGH SOUTH OF FL...FROM CUBA TO THE BAHAMAS. DURING THE WEEK
THE TROUGH WEAKENS AS IT SLIDES EAST WITH THE RIDGE DOMINATING THE
AREA. BUT BY WEEKS END THE RIDGE BEGINS TO SLIDE BACK WEST AS A LOW
MOVES FROM SE CANADA TO THE ATLANTIC...TROUGHING SOUTHWARD ALONG THE
EASTERN SEABOARD. AT THE SURFACE...HIGH PRESSURE OVER NE U.S.
COASTAL WATERS SLIDES SOUTHEASTWARD OVER THE ATLANTIC...RIDGING WEST
TO THE CENTRAL GULF COAST AS IT DOES. THIS HIGH WILL PROVIDE AN
EASTERLY AND AT TIMES ROBUST LOW LEVEL FLOW THAT BECOMES MORE
SOUTHEASTERLY AND RELAXES TOWARD THE END OF THE WEEK AS THE HIGH
REACHES THE SW ATLANTIC. THE GLOBAL MODELS CONTINUE FAIRLY
CONSISTENT WITH ONLY MINOR LOCATION AND TIMING DIFFERENCES...
ALTHOUGH THE GFS IS MORE AGGRESSIVE WITH MOISTURE AND RAINFALL. FOR
NOW HAVE FAVORED A DRIER SOLUTION WITH ONLY A SLIGHT CHANCE OF
SHOWERS/STORMS. TEMPERATURES WILL RUN ON THE WARM SIDE OF
NORMAL...BY 2 TO 4 DEGREES AT TIMES.
&&
.AVIATION...
A FEW SHOWERS THIS AFTERNOON OVER SOUTHWEST FLORIDA WITH LCL MVFR
CIGS...OTHERWISE VFR CONDITIONS WILL PREVAIL THE REMAINDER OF THE
DAY AND TONIGHT. AREAS OF BKN CIGS 035-045 REST OF THIS AFTERNOON
FROM TPA SOUTH TO RSW. LOW LEVEL CLOUDINESS WILL DECREASE THIS
EVENING WITH LOSS OF DAYTIME HEATING WITH HIGH LEVEL CLOUDINESS
REMAINING THROUGH THE NIGHT MAINLY SOUTH OF SRQ.
&&
.MARINE...
THE FORECAST WATERS WILL REMAIN BETWEEN A RIDGE OF HIGH PRESSURE TO
OUR NORTH...AND A TROUGH OF LOW PRESSURE PASSING TO OUR SOUTH. THE
LOCAL GRADIENT WILL TIGHTEN DURING THE NEXT COUPLE OF DAYS BETWEEN
THESE 2 FEATURES AND LEAD TO INCREASING WINDS AND WAVES INTO THE
EARLY PORTION OF THE WORK WEEK. THE GRADIENT SHOULD ONCE AGAIN RELAX
WEDNESDAY INTO FRIDAY ALLOWING WINDS AND SEAS TO SUBSIDE.
&&
.FIRE WEATHER...
A STEADY SUPPLY OF ATLANTIC MOISTURE WILL HELP KEEP RELATIVE
HUMIDITY VALUES GENERALLY ABOVE CRITICAL LEVELS INTO THE EARLY
PORTION OF THE WORK WEEK. NO RED FLAG CONDITIONS ARE ANTICIPATED
THROUGH MONDAY AT THIS TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 69 87 70 84 / 15 10 5 15
FMY 68 86 69 85 / 25 35 20 25
GIF 66 89 67 88 / 15 15 5 10
SRQ 68 88 69 86 / 20 15 10 15
BKV 64 89 65 88 / 15 10 5 10
SPG 72 84 71 84 / 20 10 10 15
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...14/MROCZKA
AVIATION/FIRE WEATHER...13/OGLESBY
LONG TERM...09/RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
201 PM EDT SAT APR 28 2012
.AVIATION...
MOISTURE ASSOCIATED WITH A WEAK SURFACE TROUGH CONTINUES TO STREAM
ACROSS SOUTH FLORIDA THIS AFTERNOON. OVER THE NEXT 24 HOURS THE
TROUGH WILL MAKE ITS WAY TO THE WEST KEEPING SHRAS LINGERING OVER
THE AREA. KEPT VCSH MENTION THROUGH THE PERIOD AT ALL SITES.
TSRAS HAVE DIMINISHED CONSIDERABLY OVER THE PAST COUPLE OF HOURS.
HOWEVER...CANNOT RULE OUT AN ISOLATED TSRA FOR THE REMAINDER OF
THE PERIOD BUT LEFT ANY VCTS MENTION OUT FOR NOW. EASTERLY FLOW
WILL INCREASE THROUGH THE PERIOD AND BECOME GUSTY INTO THE EVENING
HOURS.
&&
.PREV DISCUSSION... /ISSUED 1002 AM EDT SAT APR 28 2012/
UPDATE...NOT QUITE SURE WHAT TO DO WITH CURRENT FCST CONSIDERING
HEAVIEST ACTIVITY REMAINING OFFSHORE. RADAR SIGNATURES CURRENTLY
INDICATE A SFC TROUGH MAY BE LOCATED FROM NEAR NASSAU TO HST AND
THEN EXTENDING INTO THE GOMEX. BOTH THE GFS AND ECMWF ARE THE
CLOSEST TO CURRENT TRENDS AND DO KEEP THE HEAVIEST CONVECTION OVER
THE BAHAMAS AND FLORIDA KEYS NEAR AND ALONG THE TROUGH AXIS. THE
GFS, NAM AND RAPID REFRESH ALL SHOW CONVECTIVE DEVELOPMENT OVER
INTERIOR S FL BY 18-19Z AND THEN MOVES TOWARDS THE W CST THROUGH
LATE AFTERNOON WHEREAS THE ECMWF IS MORE OF A BROAD BRUSH APPROACH.
SO BASED ON THE CURRENT TRENDS AND THE MODEL CONSENSUS SOLUTIONS
FOR THE REMAINDER OF THE DAY, WILL LOWER POPS SLIGHTLY FOR THE E
CST AND RAISE SLIGHTLY FOR COASTAL COLLIER.
KOB
PREV DISCUSSION... /ISSUED 638 AM EDT SAT APR 28 2012/
AVIATION...12Z ISSUANCE...LITTLE CHANGE FROM EARLIER DISCUSSION.
DEEP LAYER MOISTURE CONTINUES TO INCREASE ACROSS THE REGION AS A
TROUGH OF LOW PRESSURE FORMS IN THE CARIBBEAN. SCT SHRA AND A FEW
TSRA WILL IMPACT AN AREA BETWEEN KPBI AND KFLL THROUGH 13Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. ANTICIPATED TSRA COVERAGE TOO
LOW TO INCLUDE VCTS ATTM. WHILE CEILINGS AND VISIBILITIES WILL
REMAIN PREVAILING VFR, BRIEF INTERVALS OF MVFR-IFR ARE CERTAINLY
POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST SURFACE WINDS WILL
CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH OCCASIONAL HIGHER
GUSTS.
PREV DISCUSSION... /ISSUED 424 AM EDT SAT APR 28 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH AND SUPPRESSES THE MOISTURE SOUTH OF THE
REGION. SO ONE SOLUTION WOULD BE MOSTLY DRY AND THE OTHER WOULD HAVE
HIGH END CHANCE POPS ACROSS THE REGION. WITH THE EASTERLY FLOW
EXPECTED...KEPT 20-40 POPS FOR THE EXTENDED THROUGH THE END OF THE
WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 80S WITH LOWS
IN THE 60S TO LOWER 70S THROUGH THE ENTIRE PERIOD.
AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
WEEKEND. FOR NOW...AM LEANING TOWARDS A GENERAL EAST WIND INCREASING
ON SUNDAY TO AROUND 20 KNOTS OVER THE ATLANTIC WATERS WITH SEAS
BUILDING TO POSSIBLY 6 FEET.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 72 80 73 82 / 50 40 40 40
FORT LAUDERDALE 72 80 72 83 / 60 60 40 40
MIAMI 71 80 72 83 / 60 60 40 40
NAPLES 69 84 69 84 / 30 40 20 40
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1035 AM EDT SAT APR 28 2012
.UPDATE (TODAY AND TONIGHT)...
14Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS NORTHERN STREAM FLOW
EXTENDING FROM OVER THE 4-CORNERS REGION EASTWARD TO THE TN/OH
VALLEYS AND THEN OFF THE MID-ATLANTIC SEABOARD. CLOSER TO HOME...OUR
FORECAST AREA IS WEDGED BETWEEN UPPER LEVEL RIDGING ALONG THE
NORTHERN GULF COAST...AND A DISTURBANCE SPINNING OVER THE YUCATAN
CHANNEL/FL STRAITS. WV IMAGERY SHOWS THE MID/UPPER LEVEL MOISTURE IS
ADVANCING NORTHWARD AHEAD OF THIS DISTURBANCE AND IS RAPIDLY ERODING
THE DRY AIR CURRENTLY OVER THE FORECAST AREA. THIS ADVANCING
MOISTURE CAN BE SEEN IN SOME SIGNIFICANT DIFFERENCES BETWEEN THE 12Z
SOUNDING PROFILES FROM TAMPA AND MIAMI. THE KTBW SOUNDING STILL
SHOWS A FAIRLY DRY COLUMN ABOVE THE BOUNDARY LAYER WITH A PW UNDER
1". THE KMFL SOUNDING ON THE OTHER HAND IS QUITE MOIST THROUGH THE
COLUMN WITH A PW APPROACHING 2". MODEL GUIDANCE IS IN GOOD AGREEMENT
IN THE CONTINUED EROSION OF THE DRY AIR OVER OUR HEADS THROUGH THE
REMAINDER OF THE DAY...AND EXPECT OUR 00Z SOUNDING TO SHOW A
SIGNIFICANT JUMP IN PW.
AT THE SURFACE...RIDGE AXIS EXTENDS FROM OFF THE SOUTHEAST COAST
WESTWARD ALONG THE I-10 CORRIDOR. GRADIENT IS STILL RATHER LIGHT OVER
OUR REGION IN CLOSE PROXIMITY TO THE RIDGE AXIS. THIS LIGHT GRADIENT
SHOULD ALLOW BOTH EAST COAST AND WEST COAST SEA-BREEZE DEVELOPMENT
THIS AFTERNOON. VERY SUMMER-LIKE FEEL TO THE AIRMASS THIS MORNING
WITH TEMPERATURES RAPIDLY CLIMBING INTO THE 80S...AND DEWPOINT WELL
UP IN TO THE 60S TO NEAR 70.
INHERITED FORECAST IS IN GOOD SHAPE. MADE A MINOR CHANGE TO EXTEND
THE SLIGHT CHANCE POPS IN PLACE OVER THE SOUTHERN ZONES NORTHWARD
THROUGH THE TAMPA BAY AREA TO AROUND BROOKSVILLE. THE INCREASING
DEEP LAYER MOISTURE AND EVENTUAL SEA-BREEZE COLLISIONS SHOULD BE
ENOUGH TO FORCE AT LEAST ISOLATED CONVECTION LATE THIS AFTERNOON
INTO THE EVENING HOURS. IN FACT...ALL OF THE AVAILABLE HI-RES
CONVECTIVE ALLOWING MODELS PRODUCE ISOLATED TO SCT SHOWERS/STORMS
LATER TODAY. OVER OUR FAR NORTHERN/NATURE COAST ZONES...KEPT THE
POPS AT A SILENT 10% UNDERNEATH THE MORE PRONOUNCED SUPPRESSION FROM
THE UPPER RIDGE.
TONIGHT...A FEW EVENING STORMS WILL FADE WITH THE LOSS OF DIURNAL
HEATING AND SEA-BREEZE FOCUS WITHIN A FEW HOURS OF SUNSET. THE
REMAINDER OF THE NIGHT LOOKS QUIET WITH GENERALLY DRY CONDITIONS AND
SEASONABLE TEMPERATURES.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL THIS AFTERNOON AND EVENING. INCREASING
HIGH CLOUDINESS WITH BKN CIGS 120-150 DEVELOPING THIS AFTERNOON WITH
SCT STRATO CU 040-050. SLIGHT CHANCE OF AN AFTERNOON/EVENING SHOWER
WITH LCL BKN040-050.
&&
.MARINE...
LIGHT EASTERLY WINDS WILL CONTINUE THROUGH THE WEEKEND WITH
AFTERNOON SEA BREEZES EXPECTED. WINDS AND SEAS WILL PICK UP
SOMEWHAT EARLY NEXT WEEK AS HIGH PRESSURE STRENGTHENS OVER THE
ATLANTIC.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 86 70 89 69 / 20 0 10 10
FMY 89 68 89 68 / 25 20 20 10
GIF 90 68 90 68 / 20 0 10 10
SRQ 86 69 88 69 / 20 10 10 10
BKV 88 63 90 63 / 15 0 0 10
SPG 86 72 86 72 / 20 0 10 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...14/MROCZKA
AVIATION...13/OGLESBY
AREA FORECAST DISCUSSION
NWS MIAMI FL
1002 AM EDT SAT APR 28 2012
.UPDATE...NOT QUITE SURE WHAT TO DO WITH CURRENT FCST CONSIDERING
HEAVIEST ACTIVITY REMAINING OFFSHORE. RADAR SIGNATURES CURRENTLY
INDICATE A SFC TROUGH MAY BE LOCATED FROM NEAR NASSAU TO HST AND
THEN EXTENDING INTO THE GOMEX. BOTH THE GFS AND ECMWF ARE THE
CLOSEST TO CURRENT TRENDS AND DO KEEP THE HEAVIEST CONVECTION OVER
THE BAHAMAS AND FLORIDA KEYS NEAR AND ALONG THE TROUGH AXIS. THE
GFS, NAM AND RAPID REFRESH ALL SHOW CONVECTIVE DEVELOPMENT OVER
INTERIOR S FL BY 18-19Z AND THEN MOVES TOWARDS THE W CST THROUGH
LATE AFTERNOON WHEREAS THE ECMWF IS MORE OF A BROAD BRUSH APPROACH.
SO BASED ON THE CURRENT TRENDS AND THE MODEL CONSENSUS SOLUTIONS
FOR THE REMAINDER OF THE DAY, WILL LOWER POPS SLIGHTLY FOR THE E
CST AND RAISE SLIGHTLY FOR COASTAL COLLIER.
KOB
&&
.PREV DISCUSSION... /ISSUED 638 AM EDT SAT APR 28 2012/
AVIATION...12Z ISSUANCE...LITTLE CHANGE FROM EARLIER DISCUSSION.
DEEP LAYER MOISTURE CONTINUES TO INCREASE ACROSS THE REGION AS A
TROUGH OF LOW PRESSURE FORMS IN THE CARIBBEAN. SCT SHRA AND A FEW
TSRA WILL IMPACT AN AREA BETWEEN KPBI AND KFLL THROUGH 13Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. ANTICIPATED TSRA COVERAGE TOO
LOW TO INCLUDE VCTS ATTM. WHILE CEILINGS AND VISIBILITIES WILL
REMAIN PREVAILING VFR, BRIEF INTERVALS OF MVFR-IFR ARE CERTAINLY
POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST SURFACE WINDS WILL
CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH OCCASIONAL HIGHER
GUSTS.
PREV DISCUSSION... /ISSUED 424 AM EDT SAT APR 28 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH AND SUPPRESSES THE MOISTURE SOUTH OF THE
REGION. SO ONE SOLUTION WOULD BE MOSTLY DRY AND THE OTHER WOULD HAVE
HIGH END CHANCE POPS ACROSS THE REGION. WITH THE EASTERLY FLOW
EXPECTED...KEPT 20-40 POPS FOR THE EXTENDED THROUGH THE END OF THE
WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 80S WITH LOWS
IN THE 60S TO LOWER 70S THROUGH THE ENTIRE PERIOD.
AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
WEEKEND. FOR NOW...AM LEANING TOWARDS A GENERAL EAST WIND INCREASING
ON SUNDAY TO AROUND 20 KNOTS OVER THE ATLANTIC WATERS WITH SEAS
BUILDING TO POSSIBLY 6 FEET.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
638 AM EDT SAT APR 28 2012
.AVIATION...12Z ISSUANCE...LITTLE CHANGE FROM EARLIER DISCUSSION.
DEEP LAYER MOISTURE CONTINUES TO INCREASE ACROSS THE REGION AS A
TROUGH OF LOW PRESSURE FORMS IN THE CARIBBEAN. SCT SHRA AND A FEW
TSRA WILL IMPACT AN AREA BETWEEN KPBI AND KFLL THROUGH 13Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. ANTICIPATED TSRA COVERAGE TOO
LOW TO INCLUDE VCTS ATTM. WHILE CEILINGS AND VISIBILITIES WILL
REMAIN PREVAILING VFR, BRIEF INTERVALS OF MVFR-IFR ARE CERTAINLY
POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST SURFACE WINDS WILL
CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH OCCASIONAL HIGHER
GUSTS.
&&
.PREV DISCUSSION... /ISSUED 424 AM EDT SAT APR 28 2012/
DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH AND SUPPRESSES THE MOISTURE SOUTH OF THE
REGION. SO ONE SOLUTION WOULD BE MOSTLY DRY AND THE OTHER WOULD HAVE
HIGH END CHANCE POPS ACROSS THE REGION. WITH THE EASTERLY FLOW
EXPECTED...KEPT 20-40 POPS FOR THE EXTENDED THROUGH THE END OF THE
WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 80S WITH LOWS
IN THE 60S TO LOWER 70S THROUGH THE ENTIRE PERIOD.
AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
WEEKEND. FOR NOW...AM LEANING TOWARDS A GENERAL EAST WIND INCREASING
ON SUNDAY TO AROUND 20 KNOTS OVER THE ATLANTIC WATERS WITH SEAS
BUILDING TO POSSIBLY 6 FEET.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 72 80 73 / 50 50 40 40
FORT LAUDERDALE 81 72 80 72 / 60 60 60 40
MIAMI 81 71 80 72 / 60 60 60 40
NAPLES 85 69 84 69 / 40 30 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AVIATION...14/MJB
AREA FORECAST DISCUSSION
NWS MIAMI FL
424 AM EDT SAT APR 28 2012
.DISCUSSION...
WATER VAPOR AND RUC ANALYSIS THIS MORNING SHOWED A LARGE PLUME OF
MOISTURE STREAMING NORTHEASTWARD FROM THE CARIBBEAN AND SOUTHWEST
ATLANTIC. THE MID/UPPER LEVEL LOW WAS STILL LOCATED ACROSS THE
NORTHWEST CARIBBEAN...AND SURFACE RIDGE AXIS ACROSS NORTH FLORIDA.
THE RIDGE WILL CONTINUE TO SLOWLY SLIDE TO THE NORTH...WITH EASTERLY
FLOW OVER SOUTH FLORIDA. PWATS HAVE INCREASED TO AROUND 2 STANDARD
DEVIATIONS ABOVE NORMAL...AND DEWPOINTS WERE NEAR 70 TO LOW 70S
ALONG THE EAST COAST METRO AREAS.
A CONVERGENCE BAND OF SHOWERS AND THUNDERSTORMS EXTENDED FROM THE
BAHAMAS AND ACROSS THE ATLANTIC WATERS AND INTO PALM BEACH COUNTY.
THIS LINE APPEARS TO BE BREAKING UP SOME. SCATTERED SHOWERS WERE
ALSO DEVELOPING SOUTH OF THIS LINE OVER THE LOCAL WATERS WITH A FEW
SHOWERS BEGINNING TO DEVELOP ACROSS MIAMI DADE AND BROWARD COUNTY AS
WELL. SOME OF THE GUIDANCE IS SUGGESTING THAT AFTER SUNRISE AND THE
SPEED CONVERGENCE ALONG THE COAST DISAPPEARS...THAT MOST OF THIS
ACTIVITY WILL BEGIN TO DISSIPATE. THE ECMWF DISAGREES AND CONTINUES
TO PUMP MOISTURE FURTHER NORTH WITH SHOWERS ACROSS THE ENTIRE REGION
THROUGH THE AFTERNOON HOURS. HOWEVER...MOST OTHER MODELS INCLUDING
THE HRRR AND LOCAL WRF SHOW LOW LEVEL SUBSIDENCE ACROSS THE REGION
AS A LOW LEVEL TROUGH DEVELOPS WELL OUT INTO THE BAHAMAS. THE
DEEPEST MOISTURE AND HEAVY RAIN WOULD THUS REMAIN WELL OUT INTO THE
ATLANTIC. FOLLOWED CLOSER TO THIS GUIDANCE AND CUT BACK POPS ACROSS
THE NORTHWEST INTERIOR FOR TODAY. KEPT THE HIGH POPS ALONG THE EAST
COAST...BUT MOST OF THE ACTIVITY MAY ONLY BE IN THE MORNING HOURS IF
THE MODEL SOLUTIONS ARE CORRECT WITH THE LOW LEVEL TROUGH AND LOW
LEVEL SUBSIDENCE LATER TODAY. BREEZY CONDITIONS ARE EXPECTED TO
DEVELOP THIS AFTERNOON ALONG THE EAST COAST AS THE PRESSURE GRADIENT
INCREASES.
THE UPPER LEVEL TROUGH/CLOSED UPPER LOW ARE EXPECTED TO BEGIN MOVING
TO THE NORTHEAST THROUGH THE DAY TODAY...AND BE LOCATED NEAR SOUTH
FLORIDA TONIGHT OR SUNDAY MORNING. MODELS HAVE BEEN FLIP FLOPPING ON
POSITIONING AND STRENGTH OF A POSSIBLE LOW LEVEL TROUGH OVER THE
BAHAMAS...WITH THE MOST RECENT RUNS SHOWING A STRONGER TROUGH.
HOWEVER...THE ECMWF STILL DOES NOT RESOLVE THIS FEATURE. COASTAL
CONVERGENCE WOULD INCREASE ALONG THE COAST AND RAINFALL CHANCES
WOULD INCREASE ALONG THE EAST COAST AND DEEP SOUTH FLORIDA AGAIN
TONIGHT. THE GFS AND NAM ARE BOTH SHOWING 20-30 KNOT SURFACE WINDS
OVER THE ATLANTIC WATERS AS THEY BOTH TRY AND DEVELOP A
HYBRID/SUBTROPICAL TYPE SYSTEM OFF THE SOUTHEAST COAST OF FLORIDA ON
SUNDAY...WITH A CLOSED SURFACE LOW OVER THE FLORIDA STRAITS. THE
ECMWF DOES NOT SHOW THIS...BUT DOES HAVE STRONGER WINDS ACROSS THE
ATLANTIC WATERS. SO IT APPEARS HEAVY RAIN WILL BE POSSIBLE LATE
TONIGHT ALONG THE EAST COAST DUE TO STRONG COASTAL CONVERGENCE. DID
NOT INCREASE WINDS DRAMATICALLY ACROSS THE REGION AND LOCAL
WATERS...AND INSTEAD OPTED TO DO A BLEND BUT STILL SHOWED SCA
CONDITIONS OVER THE ATLANTIC WATERS. BREEZY TO WINDY CONDITIONS MAY
BE POSSIBLE SUNDAY AFTERNOON...ESPECIALLY TOWARDS THE EAST COAST.
SURFACE HIGH PRESSURE IS EXPECTED TO GET REINFORCED SUNDAY INTO
MONDAY ACROSS THE ATLANTIC DUE TO HIGH PRESSURE MOVING OFF THE MID
ATLANTIC STATES. THIS SHOULD PUSH THE INVERTED TROUGH/HYBRID SYSTEM
BACK TO THE WEST IF IT DEVELOPS...AND BEGIN TO PULL THE DEEPER
MOISTURE AND HEAVIER RAINFALL BACK ACROSS SOUTH FLORIDA SUNDAY INTO
MONDAY. SO KEPT CHANCE TO LIKELY POPS ACROSS MOST OF THE REGION
THROUGH THIS TIME.
FOR THE EXTENDED...THE GFS KEEPS THE DEEP MOISTURE ACROSS THE REGION
THROUGH THE END OF THE WEEK. THE ECMWF PUSHES SURFACE HIGH OVER THE
ATLANTIC FURTHER SOUTH AND SUPPRESSES THE MOISTURE SOUTH OF THE
REGION. SO ONE SOLUTION WOULD BE MOSTLY DRY AND THE OTHER WOULD HAVE
HIGH END CHANCE POPS ACROSS THE REGION. WITH THE EASTERLY FLOW
EXPECTED...KEPT 20-40 POPS FOR THE EXTENDED THROUGH THE END OF THE
WEEK. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 80S WITH LOWS
IN THE 60S TO LOWER 70S THROUGH THE ENTIRE PERIOD.
&&
.AVIATION...06Z ISSUANCE...DEEP LAYER MOISTURE IS INCREASING
ACROSS THE REGION AS A TROUGH OF LOW PRESSURE FORMS IN THE
CARIBBEAN. SCT SHRA AND A FEW TSRA WILL IMPACT KPBI UNTIL 07Z.
OTHERWISE, VCSH IS WARRANTED FOR ALL AREAS THROUGH MUCH OF THE
TAF PERIOD, WITH THE GREATEST CHANCE OF SHRA ACTIVITY ALONG THE
SOUTHEAST COAST LATER IN THE DAY. A FEW TSRA ARE ALSO POSSIBLE,
BUT ANTICIPATED COVERAGE TOO LOW TO INCLUDE ATTM. WHILE CEILINGS
AND VISIBILITIES WILL REMAIN PREVAILING VFR, BRIEF INTERVALS OF
MVFR-IFR ARE CERTAINLY POSSIBLE IN ANY SHRA/TSRA. EAST SOUTHEAST
SURFACE WINDS WILL CONTINUE WITH SPEEDS AVERAGING 9-13 KNOTS WITH
OCCASIONAL HIGHER GUSTS.
&&
.MARINE...
MARINE CONDITIONS REMAIN UNCERTAIN WITH MODELS DIVERGING ON THE
STRENGTH OF A SFC BOUNDARY THAT MOVES NORTH ACROSS S FL OVER THE
WEEKEND. FOR NOW...AM LEANING TOWARDS A GENERAL EAST WIND INCREASING
ON SUNDAY TO AROUND 20 KNOTS OVER THE ATLANTIC WATERS WITH SEAS
BUILDING TO POSSIBLY 6 FEET.
&&
.FIRE WEATHER...
NO PROBLEMS OR CONCERNS AS DEWPOINTS REMAIN IN THE 60S TO LOWER
70S AND RAIN CHANCES REMAIN HIGH FOR MOST OF THE REGION THROUGH
THE WEEKEND INTO EARLY NEXT WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 81 72 80 73 / 50 50 40 40
FORT LAUDERDALE 81 72 80 72 / 60 60 60 40
MIAMI 81 71 80 72 / 60 60 60 40
NAPLES 85 69 84 69 / 40 30 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...14/MJB
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1229 PM CDT SAT APR 28 2012
.DISCUSSION...
ISSUED 1020 AM CDT SAT APR 28 2012
LATEST SURFACE MAP SHOWED WARM FRONT ROUGHLY ALONG A PITTSFIELD TO
LAWRENCEVILLE LINE. DEWPOINTS OF 55-60F SURGING IN FROM THE
SOUTHWEST BEHIND THE FRONT...WITH FLORA CURRENTLY UP TO 58F. SOME
CLEAR SKIES HAVE OCCURRED SOUTH OF THE FRONT AS WELL...HELPING TO
BOOST MUCAPES TO OVER 1000 J/KG ACCORDING TO LATEST SPC
MESOANALYSIS.
MAIN CONCERN FOR TODAY IS WITH CONVECTION. HIGH-RESOLUTION MODELS
AND 12Z NAM BRING THE FRONT TO NEAR THE I-72 CORRIDOR THIS
AFTERNOON...AS A WEAK SURFACE WAVE RIDES ALONG THE BOUNDARY. MOST
LIKELY LOCATION FOR CONVECTIVE INITIATION SHOULD BE AROUND SAINT
LOUIS...BEFORE FILLING IN SOUTH OF THE BOUNDARY INTO SOUTHEAST
ILLINOIS EARLY THIS AFTERNOON. SOUTHEAST CWA WILL BE WELL INTO THE
WARM SECTOR AS TEMPERATURES RISE INTO THE 70S AND DEWPOINTS REACH
60-65F...HELPING TO DESTABILIZE THINGS FURTHER AS RUC MUCAPES
REACH NEAR 3000 J/KG IN THAT AREA. SPC DAY1 SLIGHT RISK CONTINUES
ALONG AND SOUTH OF I-70.
NORTH OF THE FRONT...MOST PRECIPITATION THIS AFTERNOON SHOULD
MAINLY BE IN THE FORM OF SOME PATCHY DRIZZLE. SOME MODEST
TEMPERATURE RISES ARE EXPECTED...BUT HIGHS IN THE 50S WILL BE
COMMON NORTH OF I-74.
GEELHART
&&
.AVIATION...
ISSUED 1218 PM CDT SAT APR 28 2012
SHOWERS/STORMS HAVE BEGUN DEVELOPING ACROSS WEST CENTRAL ILLINOIS
AT MIDDAY. AWIPS TIME-OF-ARRIVAL TOOL INDICATES THE STORMS BE
NEAR KSPI AROUND 18Z AND KDEC JUST BEFORE 19Z. RADAR LOOPS WOULD
SUGGEST THEY WOULD STAY JUST BARELY SOUTH OF THE AIRPORTS...BUT
WILL MENTION TEMPO GROUPS FOR TSRA THE FIRST COUPLE HOURS TO
ACCOUNT FOR ANY NORTHWARD DEVELOPMENT. WITH WARM FRONTAL BOUNDARY
ROUGHLY ALONG THE KSPI-KCMI CORRIDOR...MOST CONVECTION WILL REMAIN
TO THE SOUTH THIS AFTERNOON.
ANY UPWARD MOVEMENT IN THE CEILING HEIGHTS THIS AFTERNOON IS
LIKELY TO COME BACK DOWN TO MVFR RANGE THIS EVENING...AS AN UPPER
WAVE SENDS SOME PERIODS OF LIGHT RAIN BACK OVER THE TAF SITES
OVERNIGHT INTO SUNDAY.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 313 AM CDT SAT APR 28 2012
RATHER COMPLICATED WEATHER PATTERN ACROSS MUCH OF THE COUNTRY THIS
MORNING. A LARGE STRONG SFC PRESSURE RIDGE FROM THE HUDSON BAY TO
THE MID ATLANTIC STATES BLOCKING THE RAPID ADVANCE OF A LOW MOVING
OUT OF THE PLAINS INTO THE MIDWEST THIS MORNING. DEEP UPPER LOW IN
ERN CANADA SLOWLY MOVING EASTWARD...AND SEVERAL MORE WAVES PROGGED
TO MOVE OUT OF THE WEST OFF OF A LOW IN THE NRN FRONT RANGE OF THE
ROCKIES. MODELS CONTINUE A RATHER WET BIAS THROUGHOUT THE
FORECAST...RESULTING IN MANY OCCURRENCES OF POPS FOR WHAT IS MORE
LIKELY TO BE SOME SHOWERY DAYS...WITH WIDESPREAD PRECIPITATION
SCARCE AT BEST.
SHORT TERM...TODAY THROUGH MONDAY...
MODELS HAVING A HARD TIME WITH THE CURRENT SITUATION AS THE LOW
MOVES NEWD INTO THE GREAT LAKES...WITH THE REMNANT BOUNDARIES LEFT
IN THE REGION AS THE LOW WEAKENS. SEVERAL SHORT WAVES EJECTED
AROUND THE DEEPER SYNOPTIC TROF TO THE WEST KEEPING THE PRECIP IN
THE REGION...INTERACTING WITH THE BOUNDARIES THROUGH THE WEEKEND.
THOUGH THE POPS ARE IN ALMOST EVERY PERIOD...IMPORTANT TO MENTION
THE MORE SHOWERY...AND NOT WIDESPREAD...NOR LONG DURATION
ANTICIPATED WITH THIS PRECIP EVENT. POSSIBILITY REMAINS THAT MUCH
OF THE FORECAST MAY END UP BETWEEN THE BEST PRECIP TO THE NORTH
AND SOUTH. HOWEVER...SOME CONCERN OUT THERE FOR SOME TS/SLIGHT
RISK OF SVR WEATHER IN THE SERN PORTION OF THE CWA THIS
AFTERNOON/EVENING...WITH MAX HEATING AND FRONT INTERACTING WITH
ANY SHORTWAVE MOVING THROUGH. MOSTLY AN ISSUE FOR HAIL/WIND...WITH
A BIT OF AN ISSUE FOR SOME MODERATE DEEP LAYER SHEAR. WET OFF AND
ON THROUGH THE WEEKEND...COOLER TODAY IN THE NORTH...AND
TEMPERATURES MODERATING SOMEWHAT TOMORROW WITH MORE EXTENSIVE
CLOUD COVER...AND THE FRONT JUST TO THE SOUTH POTENTIALLY WITH
RAIN COOLED AIR KEEPING THE WARMTH AT BAY. MONDAY PUSHING THE
FRONT A LITTLE FURTHER NORTH RESULTING IN WARMER TEMPS FOR THE SRN
PORTION OF THE STATE. HOWEVER...CONSIDERING THE UNRELIABILITY OF
THE MODELS OF LATE...HAVE AN ISSUE WITH CALLING THE LOCALE FOR THE
HIGHER POPS ALONG THE BOUNDARY. WILL REFRAIN...KEEP MORE GENERAL
POPS IN...AND ADD DETAIL AS THE MODELS COME INTO AGREEMENT.
LONG TERM...TUESDAY THROUGH FRIDAY...
ACTIVE PATTERN CONTINUES AS MODELS PUSH SMALL WAVES OUT ALONG THE
DAMPENING FLOW FROM BROADSCALE/WEAK TROFS TO THE WEST. TIMING WITH
THE ACTIVITY IS STILL A MASSIVE QUESTION MARK...AS NONE OF THESE
SYSTEMS STRIKE WITH A PARTICULARLY ORGANIZED PICTURE OVERALL.
MODERATE TEMPS AND EXTENSIVE POPS DOMINATE THE ALLBLEND AS A WEAK
SHIFT IN THE PATTERN TAKES SHAPE TO AN INCREASINGLY WESTERLY FLOW.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1022 AM CDT SAT APR 28 2012
.DISCUSSION...
ISSUED 1020 AM CDT SAT APR 28 2012
LATEST SURFACE MAP SHOWED WARM FRONT ROUGHLY ALONG A PITTSFIELD TO
LAWRENCEVILLE LINE. DEWPOINTS OF 55-60F SURGING IN FROM THE
SOUTHWEST BEHIND THE FRONT...WITH FLORA CURRENTLY UP TO 58F. SOME
CLEAR SKIES HAVE OCCURRED SOUTH OF THE FRONT AS WELL...HELPING TO
BOOST MUCAPES TO OVER 1000 J/KG ACCORDING TO LATEST SPC
MESOANALYSIS.
MAIN CONCERN FOR TODAY IS WITH CONVECTION. HIGH-RESOLUTION MODELS
AND 12Z NAM BRING THE FRONT TO NEAR THE I-72 CORRIDOR THIS
AFTERNOON...AS A WEAK SURFACE WAVE RIDES ALONG THE BOUNDARY. MOST
LIKELY LOCATION FOR CONVECTIVE INITIATION SHOULD BE AROUND SAINT
LOUIS...BEFORE FILLING IN SOUTH OF THE BOUNDARY INTO SOUTHEAST
ILLINOIS EARLY THIS AFTERNOON. SOUTHEAST CWA WILL BE WELL INTO THE
WARM SECTOR AS TEMPERATURES RISE INTO THE 70S AND DEWPOINTS REACH
60-65F...HELPING TO DESTABILIZE THINGS FURTHER AS RUC MUCAPES
REACH NEAR 3000 J/KG IN THAT AREA. SPC DAY1 SLIGHT RISK CONTINUES
ALONG AND SOUTH OF I-70.
NORTH OF THE FRONT...MOST PRECIPITATION THIS AFTERNOON SHOULD
MAINLY BE IN THE FORM OF SOME PATCHY DRIZZLE. SOME MODEST
TEMPERATURE RISES ARE EXPECTED...BUT HIGHS IN THE 50S WILL BE
COMMON NORTH OF I-74.
GEELHART
&&
.AVIATION...
ISSUED 631 AM CDT SAT APR 28 2012
CONTINUE SAME TREND OF LLWS THIS MORNING AS LOW LEVEL JET STILL
STRONG WITH SURFACE LOW OVER NORTHERN MO. AMPLE MOISTURE OVER
REGION WILL KEEP CIGS OVER REGION THROUGH DAY. DID ADD VCNTY TS
FOR SPI TAF DURING AFTERNOON...THOUGH BEST DEVELOPMENT CHANCES TO
BE SOUTHEAST OF SITE.
GOETSCH
&&
.PREV DISCUSSION...
ISSUED 313 AM CDT SAT APR 28 2012
RATHER COMPLICATED WEATHER PATTERN ACROSS MUCH OF THE COUNTRY THIS
MORNING. A LARGE STRONG SFC PRESSURE RIDGE FROM THE HUDSON BAY TO
THE MID ATLANTIC STATES BLOCKING THE RAPID ADVANCE OF A LOW MOVING
OUT OF THE PLAINS INTO THE MIDWEST THIS MORNING. DEEP UPPER LOW IN
ERN CANADA SLOWLY MOVING EASTWARD...AND SEVERAL MORE WAVES PROGGED
TO MOVE OUT OF THE WEST OFF OF A LOW IN THE NRN FRONT RANGE OF THE
ROCKIES. MODELS CONTINUE A RATHER WET BIAS THROUGHOUT THE
FORECAST...RESULTING IN MANY OCCURRENCES OF POPS FOR WHAT IS MORE
LIKELY TO BE SOME SHOWERY DAYS...WITH WIDESPREAD PRECIPITATION
SCARCE AT BEST.
SHORT TERM...TODAY THROUGH MONDAY...
MODELS HAVING A HARD TIME WITH THE CURRENT SITUATION AS THE LOW
MOVES NEWD INTO THE GREAT LAKES...WITH THE REMNANT BOUNDARIES LEFT
IN THE REGION AS THE LOW WEAKENS. SEVERAL SHORT WAVES EJECTED
AROUND THE DEEPER SYNOPTIC TROF TO THE WEST KEEPING THE PRECIP IN
THE REGION...INTERACTING WITH THE BOUNDARIES THROUGH THE WEEKEND.
THOUGH THE POPS ARE IN ALMOST EVERY PERIOD...IMPORTANT TO MENTION
THE MORE SHOWERY...AND NOT WIDESPREAD...NOR LONG DURATION
ANTICIPATED WITH THIS PRECIP EVENT. POSSIBILITY REMAINS THAT MUCH
OF THE FORECAST MAY END UP BETWEEN THE BEST PRECIP TO THE NORTH
AND SOUTH. HOWEVER...SOME CONCERN OUT THERE FOR SOME TS/SLIGHT
RISK OF SVR WEATHER IN THE SERN PORTION OF THE CWA THIS
AFTERNOON/EVENING...WITH MAX HEATING AND FRONT INTERACTING WITH
ANY SHORTWAVE MOVING THROUGH. MOSTLY AN ISSUE FOR HAIL/WIND...WITH
A BIT OF AN ISSUE FOR SOME MODERATE DEEP LAYER SHEAR. WET OFF AND
ON THROUGH THE WEEKEND...COOLER TODAY IN THE NORTH...AND
TEMPERATURES MODERATING SOMEWHAT TOMORROW WITH MORE EXTENSIVE
CLOUD COVER...AND THE FRONT JUST TO THE SOUTH POTENTIALLY WITH
RAIN COOLED AIR KEEPING THE WARMTH AT BAY. MONDAY PUSHING THE
FRONT A LITTLE FURTHER NORTH RESULTING IN WARMER TEMPS FOR THE SRN
PORTION OF THE STATE. HOWEVER...CONSIDERING THE UNRELIABILITY OF
THE MODELS OF LATE...HAVE AN ISSUE WITH CALLING THE LOCALE FOR THE
HIGHER POPS ALONG THE BOUNDARY. WILL REFRAIN...KEEP MORE GENERAL
POPS IN...AND ADD DETAIL AS THE MODELS COME INTO AGREEMENT.
LONG TERM...TUESDAY THROUGH FRIDAY...
ACTIVE PATTERN CONTINUES AS MODELS PUSH SMALL WAVES OUT ALONG THE
DAMPENING FLOW FROM BROADSCALE/WEAK TROFS TO THE WEST. TIMING WITH
THE ACTIVITY IS STILL A MASSIVE QUESTION MARK...AS NONE OF THESE
SYSTEMS STRIKE WITH A PARTICULARLY ORGANIZED PICTURE OVERALL.
MODERATE TEMPS AND EXTENSIVE POPS DOMINATE THE ALLBLEND AS A WEAK
SHIFT IN THE PATTERN TAKES SHAPE TO AN INCREASINGLY WESTERLY FLOW.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1153 PM CDT FRI APR 27 2012
.DISCUSSION...
ISSUED 836 PM CDT FRI APR 27 2012
LOW PRESSURE OVER KANSAS WILL LIFT NORTHEASTWARD TONIGHT...REACHING
NORTHEAST MISSOURI BY SATURDAY MORNING. VERY DRY AIRMASS PRECEDING
THIS FEATURE WILL KEEP CENTRAL ILLINOIS DRY THROUGH THE EVENING...WITH
SHOWERS SPREADING INTO THE AREA OVERNIGHT. LATEST RADAR
MOSAIC SHOWS SHOWERS/STORMS DEVELOPING IN THE WARM SECTOR OF THE
SYSTEM OVER NORTHWEST MISSOURI...AND THESE ARE EXPECTED TO LIFT/DEVELOP
INTO WEST-CENTRAL ILLINOIS AFTER MIDNIGHT. BASED ON CURRENT
TRAJECTORY AND LATEST HRRR DATA...THINK MAINLY THE N/NW KILX CWA
WILL BE IMPACTED. AS SUCH...HAVE ADJUSTED POPS TO GO LIKELY ALONG
AND NORTHWEST OF A JACKSONVILLE TO DANVILLE LINE...WITH ONLY
CHANCE POPS FURTHER SOUTH AND EAST. GIVEN DRY AIRMASS...CONVECTION
WILL BE WEAKENING AS IT APPROACHES...RESULTING IN MAINLY SHOWERS
WITH PERHAPS A RUMBLE OF THUNDER. UPDATED ZONES HAVE ALREADY BEEN
ISSUED.
&&
.AVIATION...
ISSUED 1153 PM CDT FRI APR 27 2012
NOT A LOT OF CHANGES IN FORECAST TRENDS FOR THE 06Z TAFS EXPECTED.
SOME OF THE PCPN WILL TRY TO TIME WITH THE 2 WAVES OF SHOWERS SEEN
ON RADAR. THESE SUPPORTED BY SPOKES OF UPPER LEVEL VORT WRAPPING
AROUND THE NE VORT MAX. MAIN CONCERN NOW IS POSSIBLE LLWS
OVERNIGHT DUE TO THE PROGGED LOW LEVEL JET FROM THE SOUTHWEST
INTENSIFYING OVER MO-IL AS SURFACE LOW MOVES INTO NORTH MO
OVERNIGHT. STILL LOOKING AT THIS...BUT WILL HAVE TO ADD THIS DUE
TO EXPECTED SIGNIFICANT DEVELOPING SHEAR.
GOETSCH
&&
.PREV DISCUSSION...
ISSUED 200 PM CDT FRI APR 27 2012
WATER VAPOR LOOP SHOWING TWO DISTINCT UPPER WAVES TO OUR WEST.
THE STRONGER OF THE TWO SHORTWAVES WAS LOCATED OVER SOUTHWEST
MONTANA WITH THE SECONDARY WAVE ACRS WESTERN KS...WHICH IS BEING
DRAWN NORTHWARD AS IT ENCOUNTERS A BLOCKING RIDGE ACRS THE
NORTHERN PLAINS. FURTHER EAST...A LARGE CANADIAN HIGH WAS ANCHORED
NORTH OF THE GREAT LAKES EARLY THIS AFTERNOON HELPING TO DRAWN
DOWN SOME COOL AND VERY DRY AIR SOUTH INTO OUR AREA.
SHORT TERM...TONIGHT THROUGH MONDAY NIGHT
SEVERAL CONCERNS THIS FORECAST PERIOD INCLUDING...TIMING OF RAIN
ACROSS THE FORECAST AREA THIS EVENING AND THEN CONVECTION CHANCES
INCLUDING SEVERE THREAT AROUND THE I-70 CORRIDOR TOMORROW AFTERNOON.
AFTER THAT...A SERIES OF WEATHER SYSTEMS MOVE OUT OF THE SOUTHERN
PLAINS AND INTERACT WITH A FRONTAL BOUNDARY WHICH WILL BE SHIFTING
SLOWLY NORTH AS THE LARGE CANADIAN HIGH FINALLY EDGES OFF TO OUR
EAST. THIS WILL BRING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS
THROUGH EARLY NEXT WEEK.
FORECAST SOUNDINGS SHOWING ONLY A SLOW MOISTENING OF THE LOWER LEVELS
THIS EVENING AS THE SURFACE LOW PRESSURE AREA ASSOCIATED WITH THE KANSAS
UPPER WAVE MOVES INTO NORTHERN MISSOURI BY LATE TONIGHT. IT APPEARS
WE WILL SEE OUR BEST THREAT FOR SHOWERS AND ISOLATED THUNDERSTORMS LATE
THIS EVENING WEST...AND THEN SHIFTING NORTHEAST OVER THE REMAINDER
OF THE AREA LATE TONIGHT...BEFORE EDGING OUT OF OUR AREA BY LATE SATURDAY
MORNING AS THE SURFACE WAVE SHIFTS INTO EAST CENTRAL MO/SOUTHWEST ILLINOIS
BY NOON. LOOKS AS IF THE NAM-WRF HANGS ON TO THE IDEA OF A CLOSED SFC
WAVE TOO LONG BASED ON THE UPPER SYSTEM PULLING WELL OF TO ITS NW DURING
THE MORNING.
LOCAL HI-RES MODELS SUGGEST THE WARM FRONT WILL PUSH TO JUST SOUTH
OF I-70 BY EARLY TOMORROW AFTERNOON WITH STEEP MID LEVEL LAPSE RATES
OF UP TO 8 DEG/C AND MIXED LAYER CAPES OF 1500-2000 J/KG ALONG AND
JUST SOUTH OF THE WARM FRONT. SCATTERED STORMS ARE EXPECTED TO DEVELOP
IN THE 18Z-21Z TIME FRAME JUST EAST OF THE WEAKENING SFC WAVE AND
ALONG/JUST SOUTH OF THE WARM FRONT. AT THIS TIME...IT APPEARS THE PRIMARY
MODE OF CONVECTION TOMORROW AFTERNOON WOULD BE INITIALLY SUPERCELLUAR
WHICH WOULD QUICKLY TRANSLATE MORE INTO A LINEAR MODE BASED ON THE
UNIDIRECTIONAL WINDS FORECAST IN SE IL. PRIMARY THREAT WOULD BE LARGE
HAIL AND DAMAGING WINDS...WITH AN ISOLATED TORNADO POSSIBLE...ESP JUST
EAST OF THE SFC WAVE AND ALONG THE WARM FRONT.
ANY LINGERING CONVECTION SHOULD COME TO AN END BY 00Z ACRS SE IL WITH
THE BOUNDARY GETTING NUDGED BACK SOUTH AGAIN AS THE CANADIAN HIGH
BUILDS BACK INTO THE AREA SATURDAY EVENING. WILL CONTINUE TO HOLD
ON TO CHANCE POPS ACRS SOUTHERN IL AS THE BOUNDARY WILL NOT BE THAT
FAR AWAY. MEANWHILE...FURTHER TO THE NORTHWEST...THE UPPER LOW SHIFTS
SLOWLY NORTH INTO SOUTHERN CANADA AS THE RELENTLESS BLOCK HOLDS FIRM
ACRS THE NORTHERN PLAINS AND WESTERN GREAT LAKES. MODELS BEGIN TO
BUILD THE HEIGHTS ACRS THE AREA IN RESPONSE TO THE RETREATING UPPER
WAVE WHICH SHOULD ALLOW THE LARGE CANADIAN HIGH TO EDGE FURTHER
EAST ON SUNDAY/SUNDAY NIGHT. THE FRONTAL BOUNDARY TO OUR SOUTH WILL
BEGIN TO PUSH BACK NORTH DURING THIS TIME FRAME WITH ALL MODELS
INDICATING WEAK DISTURBANCES MOVING OUT OF THE SOUTHERN PLAINS. ONE
SUCH WAVE WILL PUSH ALONG THE BOUNDARY AND BRING AN INCREASING
THREAT FOR SHOWERS/THUNDERSTORMS LATE SUNDAY INTO A PORTION OF MONDAY
BEFORE SHIFTING OFF TO OUR EAST MONDAY NIGHT.
LONG TERM...TUESDAY THROUGH FRIDAY
A WARMER AND ACTIVE WEATHER PATTERN CONTINUES TO BE DEPICTED ON
MEDIUM RANGE MODELS DURING THIS FORECAST PERIOD...HOWEVER...TIMING
OF INDIVIDUAL SHORTWAVES ACRS THE AREA AS THE PATTERN DEAMPLIFIES
CONTINUES TO BE A CHALLENGE WITH RESPECT TO PRECIP CHANCES EACH DAY.
PATTERN TRANSITIONS INTO MORE OF A ZONAL FLOW EARLY IN THE FORECAST
PERIOD...THEN THE UPPER FLOW SHIFTS TO SOUTHWESTERLY LATE IN THE WEEK
AS A TROF SHIFTS INTO THE WEST COAST. MOST OF OUR AREA WILL BE ALONG
THE SOUTHERN PERIPHERY OF THE STRONGER WINDS ALOFT...WHICH USUALLY
TRANSLATES TO PERIODIC CONVECTION CHANCES THIS TIME OF YEAR...AND
UNFORTUNATELY...THIS IS THE CASE THRU THE EXTENDED PORTION OF THE
FORECAST. ALTHOUGH TEMPERATURES WILL WARM WELL INTO THE 70`S TO
LOWER 80S STARTING TUESDAY...THE PATTERN CONTINUES TO SUPPORT A
LEAST MENTIONABLE POPS IN THE GRIDS EACH DAY.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1030 PM EDT SUN APR 29 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 352 PM EDT SUN APR 29 2012
A BROAD QUASI ZONAL TO SOUTHWEST FLOW WILL MAINTAIN ITSELF OVER
MOST OF THE NEXT WEEK...WITH SEVERAL FRONTAL WAVES AND THUS
OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS PRESENTING THEMSELVES
ACROSS CENTRAL INDIANA. THIS SOUTHWEST FLOW WILL ALSO ALLOW
TEMPERATURES TO BE SEASONABLY WARM FOR MUCH OF THE NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 1030 PM EDT SUN APR 29 2012
HAD TO LOWER TEMPERATURES A FEW DEGREES AT MANY LOCALES BASED ON
OBSERVATIONS AND THE WARM FRONT STILL JUST SOUTHWEST OF THE
INDIANAPOLIS COUNTY WARNING AREA. THE FRONT IS STILL EXPECTED TO
LIFT NORTHEAST ACROSS NORTHEAST PARTS OF THE FORECAST AREA BY 12Z
MONDAY. MEANWHILE...A FEW SHOWERS WERE DEVELOPING ACROSS
ILLINOIS AND MAY GRAZE OUR NORTHWEST OVERNIGHT IN ADDITION TO STORMS
ACROSS MISSOURI. THUNDERSTORMS ARE ALSO POSSIBLE WITH MOST UNSTABLE
CAPES TO AROUND 300 J/KG ACROSS OUR NORTHEAST AND 900 OVERNIGHT.
STILL...LIKELY LOOKS GOOD NORTHWEST LESSENING TO SLIGHT CHANCE
SOUTHEAST.
PREVIOUS DISCUSSION FOLLOWS...
FOCI FOR TONIGHT ARE POPS AND THUNDER CHANCES. MODELS ARE IN
GENERAL AGREEMENT ON LARGE SCALE FEATURES...BUT LEANED TOWARD NAM
AS OTHER MODELS APPEAR TO BE TOO WET BASED ON CURRENT TRENDS.
WARM FRONT SHOULD GRADUALLY PUSH NORTHWARD TONIGHT...AS A WEAK
SURFACE LOW MOVES OUT OF THE CENTRAL PLAINS. MOST GUIDANCE
APPEARED A BIT TOO AGGRESSIVE ON PRECIP WHEN MUCH OF THE
CONVECTION TO OUR WEST HAS STRUGGLED TO MAKE IT EASTWARD TODAY.
RAPID REFRESH AND RUC DEPICT BEST CHANCES OF PRECIP TONIGHT ACROSS
OUR NORTHWEST...AND CONSENSUS APPROACH TEMPERED SLIGHTLY DEPICTS
THIS WELL. INSTABILITY IS THERE BUT MINIMAL...AND BASED ON SREF
THUNDER PROBS HAVE GONE WITH ISOLATED THUNDER MENTION RATHER THAN
STRAIGHT THUNDERSTORM FORECAST. DID GO WITH CHANCE THUNDER IN THE
NORTHWEST LATE WHERE PROBABILTIES ARE A BIT HIGHER.
CONSENSUS APPROACH ON TEMPS AGREES WELL WITH UPSTREAM MINS FROM
LAST NIGHT...AND WILL STICK CLOSE TO THIS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCUS REMAINS PRECIP CHANCES THROUGHOUT...WITH BOUNDARY REMAINING
IN THE AREA IN ONE FORM OR ANOTHER AND ONE OR MORE VERY SUBTLE
WAVES PERHAPS AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. POPS
APPEARED A BIT HIGH IN PLACES...BUT NOT BY MUCH...GIVEN THE LACK
OF SIGNIFICANT UPPER LEVEL SUPPORT THROUGH THE FIRST PART OF THE
WEEK. HOWEVER...EXPECT THAT MESOSCALE INFLUENCES WILL HELP MAKE UP
FOR THIS. LEANED HEAVILY ON SREF THUNDER PROBS AND BOUNDARY
POSITION FOR DELINEATING BETWEEN WHERE TO FORECAST STRAIGHT
THUNDERSTORMS AND WHERE TO GO MORE SHOWERS WITH ISOLATED THUNDER
MENTION.
SLIGHT RISK FOR TOMORROW AND SEE TEXT FOR TUESDAY APPEAR
REASONABLE BASED ON MODEL CAPE/SHEAR PROFILES. IN SOMEWHAT TYPICAL
FASHION...AFTERNOON AND EARLY EVENING WOULD BE PREFERRED TIMES FOR
SEVERE BOTH DAYS.
ON TEMPS...GENERALLY A CONSENSUS APPROACH LOOKED OK...EXCEPT IT
APPEARED TO BE A FEW DEGREES COOL IN MOST PERIODS BASED ON LOW
LEVEL THICKNESSES. MINOR TWEAKS UPWARD WERE REQUIRED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 230 PM EDT SUN APR 29 2012
ECMWF AND GFS HINT AT A LINGERING FRONTAL BOUNDARY AND NUMEROUS
WEAK SHORT WAVES PUSHING THROUGH THE OHIO VALLEY THROUGH THE FIRST
PART OF THE WEEKEND. CONFIDENCE IN THESE FEATURES IS
LOW...ALTHOUGH GIVEN THE PATTERN...LOW CHANCE POPS WILL BE NEEDED
THROUGH MUCH OF THE WORK WEEK. ALL BLEND HANDLES THIS RATHER WELL.
BY NEXT SUNDAY...THE ECMWF IS SIGNALING A CHANGE AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES...PUSH THE FRONTAL BOUNDARY SOUTH.
FOR NOW THIS WILL BE THE MAIN PERIOD WHERE WE WILL BE ABLE TO
REMOVE THE POPS.
THE SOUTHERLY FLOW EXPECTED THROUGH THE PERIOD ALONG WITH SHOULD
PROVIDE ABOVE NORMAL TEMPERATURES THROUGH MUCH OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 300300Z KIND TAF UPDATE/...
ISSUED AT 1022 PM EDT SUN APR 29 2012
NO SIGNIFICANT CHANGES MADE TO THE FORECAST. PREVIOUS DISCUSSION
FOLLOWS.
TAIL END OF UPPER DISTURBANCE PASSING OVER NORTHERN ILLINOIS IS
EXPECTED TO BE IN THE PROCESS OF MOVING ACROSS THE LOCAL AREA BY THE
BEGINNING OF THE FORECAST PERIOD. NOTHING REALLY DEVELOPING ON THIS
TAIL...BUT THERE IS SOME ELEVATED INSTABILITY AROUND. AS A
RESULT...THERE IS A LOW POTENTIAL FOR CONVECTION IN THE VICINITY OF
THE TAF SITES THROUGH ABOUT 300200Z...BUT NOT ENOUGH TO PUT IN THE
FORECAST AT THIS TIME.
MODEL DATA SUGGEST THERE MAY BE ANOTHER DISTURBANCE MOVING INTO THE
AREA OUT OF THE SOUTHERN PLAINS AFTER 300800Z...BUT AGAIN COVERAGE
OF CONVECTION TOO QUESTIONABLE TO PUT IN THE FORECAST AT THIS TIME.
CEILINGS GENERALLY ABOVE 050 EXPECTED TO LOWER INTO THE 030-050
RANGE AFTER 300600Z WITH THE APPROACH OF WARM FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD/KOCH
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1022 PM EDT SUN APR 29 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 352 PM EDT SUN APR 29 2012
A BROAD QUASI ZONAL TO SOUTHWEST FLOW WILL MAINTAIN ITSELF OVER
MOST OF THE NEXT WEEK...WITH SEVERAL FRONTAL WAVES AND THUS
OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS PRESENTING THEMSELVES
ACROSS CENTRAL INDIANA. THIS SOUTHWEST FLOW WILL ALSO ALLOW
TEMPERATURES TO BE SEASONABLY WARM FOR MUCH OF THE NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCI FOR TONIGHT ARE POPS AND THUNDER CHANCES. MODELS ARE IN
GENERAL AGREEMENT ON LARGE SCALE FEATURES...BUT LEANED TOWARD NAM
AS OTHER MODELS APPEAR TO BE TOO WET BASED ON CURRENT TRENDS.
WARM FRONT SHOULD GRADUALLY PUSH NORTHWARD TONIGHT...AS A WEAK
SURFACE LOW MOVES OUT OF THE CENTRAL PLAINS. MOST GUIDANCE
APPEARED A BIT TOO AGGRESSIVE ON PRECIP WHEN MUCH OF THE
CONVECTION TO OUR WEST HAS STRUGGLED TO MAKE IT EASTWARD TODAY.
RAPID REFRESH AND RUC DEPICT BEST CHANCES OF PRECIP TONIGHT ACROSS
OUR NORTHWEST...AND CONSENSUS APPROACH TEMPERED SLIGHTLY DEPICTS
THIS WELL. INSTABILITY IS THERE BUT MINIMAL...AND BASED ON SREF
THUNDER PROBS HAVE GONE WITH ISOLATED THUNDER MENTION RATHER THAN
STRAIGHT THUNDERSTORM FORECAST. DID GO WITH CHANCE THUNDER IN THE
NORTHWEST LATE WHERE PROBABILTIES ARE A BIT HIGHER.
CONSENSUS APPROACH ON TEMPS AGREES WELL WITH UPSTREAM MINS FROM
LAST NIGHT...AND WILL STICK CLOSE TO THIS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCUS REMAINS PRECIP CHANCES THROUGHOUT...WITH BOUNDARY REMAINING
IN THE AREA IN ONE FORM OR ANOTHER AND ONE OR MORE VERY SUBTLE
WAVES PERHAPS AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. POPS
APPEARED A BIT HIGH IN PLACES...BUT NOT BY MUCH...GIVEN THE LACK
OF SIGNIFICANT UPPER LEVEL SUPPORT THROUGH THE FIRST PART OF THE
WEEK. HOWEVER...EXPECT THAT MESOSCALE INFLUENCES WILL HELP MAKE UP
FOR THIS. LEANED HEAVILY ON SREF THUNDER PROBS AND BOUNDARY
POSITION FOR DELINEATING BETWEEN WHERE TO FORECAST STRAIGHT
THUNDERSTORMS AND WHERE TO GO MORE SHOWERS WITH ISOLATED THUNDER
MENTION.
SLIGHT RISK FOR TOMORROW AND SEE TEXT FOR TUESDAY APPEAR
REASONABLE BASED ON MODEL CAPE/SHEAR PROFILES. IN SOMEWHAT TYPICAL
FASHION...AFTERNOON AND EARLY EVENING WOULD BE PREFERRED TIMES FOR
SEVERE BOTH DAYS.
ON TEMPS...GENERALLY A CONSENSUS APPROACH LOOKED OK...EXCEPT IT
APPEARED TO BE A FEW DEGREES COOL IN MOST PERIODS BASED ON LOW
LEVEL THICKNESSES. MINOR TWEAKS UPWARD WERE REQUIRED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 230 PM EDT SUN APR 29 2012
ECMWF AND GFS HINT AT A LINGERING FRONTAL BOUNDARY AND NUMEROUS
WEAK SHORT WAVES PUSHING THROUGH THE OHIO VALLEY THROUGH THE FIRST
PART OF THE WEEKEND. CONFIDENCE IN THESE FEATURES IS
LOW...ALTHOUGH GIVEN THE PATTERN...LOW CHANCE POPS WILL BE NEEDED
THROUGH MUCH OF THE WORK WEEK. ALL BLEND HANDLES THIS RATHER WELL.
BY NEXT SUNDAY...THE ECMWF IS SIGNALING A CHANGE AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES...PUSH THE FRONTAL BOUNDARY SOUTH.
FOR NOW THIS WILL BE THE MAIN PERIOD WHERE WE WILL BE ABLE TO
REMOVE THE POPS.
THE SOUTHERLY FLOW EXPECTED THROUGH THE PERIOD ALONG WITH SHOULD
PROVIDE ABOVE NORMAL TEMPERATURES THROUGH MUCH OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 300300Z KIND TAF UPDATE/...
ISSUED AT 1022 PM EDT SUN APR 29 2012
NO SIGNIFICANT CHANGES MADE TO THE FORECAST. PREVIOUS DISCUSSION
FOLLOWS.
TAIL END OF UPPER DISTURBANCE PASSING OVER NORTHERN ILLINOIS IS
EXPECTED TO BE IN THE PROCESS OF MOVING ACROSS THE LOCAL AREA BY THE
BEGINNING OF THE FORECAST PERIOD. NOTHING REALLY DEVELOPING ON THIS
TAIL...BUT THERE IS SOME ELEVATED INSTABILITY AROUND. AS A
RESULT...THERE IS A LOW POTENTIAL FOR CONVECTION IN THE VICINITY OF
THE TAF SITES THROUGH ABOUT 300200Z...BUT NOT ENOUGH TO PUT IN THE
FORECAST AT THIS TIME.
MODEL DATA SUGGEST THERE MAY BE ANOTHER DISTURBANCE MOVING INTO THE
AREA OUT OF THE SOUTHERN PLAINS AFTER 300800Z...BUT AGAIN COVERAGE
OF CONVECTION TOO QUESTIONABLE TO PUT IN THE FORECAST AT THIS TIME.
CEILINGS GENERALLY ABOVE 050 EXPECTED TO LOWER INTO THE 030-050
RANGE AFTER 300600Z WITH THE APPROACH OF WARM FRONT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
648 PM CDT SUN APR 29 2012
...UPDATED FOR 00Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
FORECAST CONCERNS CENTER AROUND CHANCE FOR LINGERING PRECIPITATION
TONIGHT. LARGE AREA OF PRECIP CONTINUES TO PUSH NORTH THROUGH THE
CWA...AND LINES UP WELL WITH ISENTROPIC LIFT AREA ON THE RUC 290K
SURFACE. HAVE TRENDED POPS TO CORRELATE WITH THIS AREA OF LIFT
TRANSLATING NORTH TO NORTHEASTWARD WITH TIME OVER THE NEXT 3 TO 6
HOURS. DEEPER SATURATION ENDS BY MID EVENING...WITH SOME DRIER AIR
MOVING IN ALOFT...WITH LOWEST LAYERS REMAINING SATURATED. SOME WEAK
ISENTROPIC LIFT STILL AROUND IN AREAS WITH THE MORE SHALLOW
SATURATION...THEREFORE HAVE ALSO MENTIONED SOME PATCHY DRIZZLE FOR
THE EVENING HOURS. ANY ELEVATED INSTABILITY CONFINED TO THE SOUTHERN
PORTION OF THE CWA...BUT HAS NOT MATERIALIZED MUCH EVEN THIS
AFTERNOON...SO ONLY HAVE SOME ISOLATED THUNDER MENTION ACROSS FAR
SOUTH FOR THIS EVENING. WITH THE SHALLOW LOW LEVEL
SATURATION...EXPECT STRATUS TO CONTINUE THROUGH THE NIGHT. WITH
WINDS EXPECTED TO BECOME LIGHT AND VARIABLE AS WEAK HIGH PRESSURE
BUILDS INTO THE STATE...SHALLOW MOISTURE AND RESIDUAL SURFACE
MOISTURE FROM THE RAINFALL COULD ALSO HAVE AREAS OF FOG POSSIBLY
DENSE FORM ACROSS THE CWA BY LATE EVENING INTO THE OVERNIGHT HOURS.
FOR NOW JUST MENTIONED THE FOG IN THE GRIDS...BUT WILL HAVE TO
MONITOR ITS DEVELOPMENT TO DETERMINE IF IT WILL BECOME DENSE.
OVERALL EXPECT PRECIP TO CLEAR FASTER THAN IN PREVIOUS
FORECASTS...SO HAVE ENDED ANY PRECIPITATION BY LATE EVENING AND HAVE
GONE DRY IN THE LATE NIGHT HOURS.
.LONG TERM /MONDAY THROUGH SUNDAY/...
WITH SYSTEM MOVING A BIT FASTER...MON SHOULD BE A DRY DAY AND LIKELY
THE ONLY FULLY DRY PERIOD OF THE FORECAST. BROAD SOUTHWEST FLOW
WILL PERSIST OVER THE CENTRAL U.S. FOR THE NEXT WEEK WITH A SERIES
OF UPPER LEVEL SYSTEM S LIFTING NEWD OUT OF THE SOUTHWEST U.S.
TIMING WILL BE TRICKY...BUT IT DOES APPEAR THERE WILL BE SOME RAIN
DURING EACH OF THE 12 HOUR PERIODS OF THE FORECAST...THOUGH NOT ALL
OF IT. THERE WILL BE INTERMITTENT CHANCES FOR SEVERE WEATHER WITH
THE BEST CHANCES LOOKING LIKE TUE NIGHT AND FRIDAY NIGHT RIGHT NOW.
SOME CAPPING IS BEGINNING TO TAKE PLACE WHICH WILL CUT DOWN THE
SEVERE POTENTIAL SOME. ALL IN ALL IT DOES LOOK LIKE A DECENT AMOUNT
OF RAIN DURING THE NEXT WEEK. NOT SURE THE HEAVIEST WILL BE IN THE
DRIEST AREAS HOWEVER. THE THE DRY NWRN ZONES WILL GET ABOVE NORMAL
RAINFALL THIS WEEK. TEMPS WILL WARM ABOVE NORMAL ON MONDAY AND
REMAIN THAT WAY THROUGH THE WEEK.
&&
.AVIATION...30/00Z
LOW LEVEL EASTERLY WINDS AND MOISTURE WILL CONTINUE TO PRODUCE
WIDESPREAD IFR OVERNIGHT AT ALL TAFS SITES. LIGHT RAIN AND DRIZZLE
WILL DIMINISH THIS EVENING AS ISENTROPIC LIFT PULLS NORTHEAST INTO
MN AND WI. AREAS OF FOG...LOCALLY DENSE ARE ALSO EXPECTED OVERNIGHT
AS WAA CONTINUES. THE POOR CONDITIONS WILL IMPROVE ON MONDAY AS
WINDS BECOME SOUTHWEST AND INCREASE DURING THE DAY. THIS WILL ALLOW
THE LOW LEVEL INVERSION THAT HAS BEEN IN PLACE TO GRADUALLY MIX OUT
WITH FOG AND STRATUS DISSIPATING DURING THE MORNING. WIDESPREAD VFR
CONDITIONS ARE THEN EXPECTED BY MONDAY AFTERNOON AT ALL TAF SITES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MJB
LONG TERM...MS APR 12
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1215 PM CDT SAT APR 28 2012
.AVIATION...
STORM SYSTEM WILL PUSH EASTWARD WITH DRIER AIR FILTERING IN BEHIND
THE SYSTEM. CURRENTLY MVFR CEILINGS AT KCID...KMLI....AND KBRL WITH
IFR CEILINGS AT KDBQ. CEILINGS ARE EXPECTED TO LIFT THIS AFTERNOON
WITH SOME HEATING...ALTHOUGH CIGS A KDBQ WILL SEE THE LEAST
IMPROVEMENT WITH SURFACE TEMPS NOT EXPECTED TO RISE MUCH.
OCCASIONAL DRIZZLE OR SPRINKLES ARE POSSIBLE AT ALL SITES THIS
AFTERNOON.
CEILINGS WILL LOWER AND THICKEN AGAIN OVERNIGHT FROM SOUTHWEST TO
NORTHEAST BUT REMAIN MVFR AS MOISTURE AHEAD OF ANOTHER STORM SYSTEM
MOVES INTO THE MID MISSISSIPPI VALLEY. INTRODUCED VCSH AT KBRL AS
MODELS HINT THAT SHOWERS MAY MOVE INTO SOUTHEASTERN IOWA BY 18 UTC.
DC/DLF
&&
.PREV DISCUSSION... /ISSUED 1002 AM CDT SAT APR 28 2012/
UPDATE...
AN UPDATED ZFP AND GRIDS WERE SENT WITH SOME MINOR ADJUSTMENTS TO
THE PRECIP WORDING FOR THE REST OF THE MORNING. THE BULK OF THE
MEASURABLE RAIN HAS MOVED OUT OF EAST CENTRAL IOWA SO SCALED BACK
ON THE PRECIP WORDING FOR THE REST OF THE MORNING TO MAINLY PATCHY DRIZZLE.
ALSO ADDED SOME SPRINKLES OVER THE SOUTH HALF OF THE CWFA.
LATEST 88D DATA WAS SHOWING SOME SPOTTY SHRA OVER SOUTHEAST IOWA.
THE SHRA WAS IN AN AREA OF WEAK BUT DEEP FGEN WHICH THE RUC KEEPS
OVER THE SOUTH THROUGH 18Z. THE RUC WAS ALSO SHOWING THAT THE BEST RH
WAS IN THE 700-500MB LAYER WITH A DRY LAYER BELOW...SO -SHRA BASED
THIS LAYER SHOULD AMOUNT TO LITTLE MORE THE SPRINKLES. TEMPERATURES
WERE LEFT UNTOUCHED AT THIS TIME. HIGHS AROUND 60 IN THE SOUTH
SEEMS A BIT OPTIMISTIC...BUT THE CLEARING/WARMER AIR IS WITHIN A
COUNTY OF OUR SOUTHTERN BORDER...CLOSE ENOUGH TO HOLD ON TO THE CURRENT
FORECAST. ALSO THE MID 40S IN THE NORTH THIS AFTERNOON MAY BE ON
THE OPTIMISTIC SIDE WITH A STIFF EAST WIND AND LOW OVERCAST SKIES
THROUGH THE AFTERNOON. DLF
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1002 AM CDT SAT APR 28 2012
.UPDATE...
AN UPDATED ZFP AND GRIDS WERE SENT WITH SOME MINOR ADJUSTMENTS TO
THE PRECIP WORDING FOR THE REST OF THE MORNING. THE BULK OF THE
MEASURABLE RAIN HAS MOVED OUT OF EAST CENTRAL IOWA SO SCALED BACK
ON THE PRECIP WORDING FOR THE REST OF THE MORNING TO MAINLY PATCHY DRIZZLE.
ALSO ADDED SOME SPRINKLES OVER THE SOUTH HALF OF THE CWFA.
LATEST 88D DATA WAS SHOWING SOME SPOTTY SHRA OVER SOUTHEAST IOWA.
THE SHRA WAS IN AN AREA OF WEAK BUT DEEP FGEN WHICH THE RUC KEEPS
OVER THE SOUTH THROUGH 18Z. THE RUC WAS ALSO SHOWING THAT THE BEST RH
WAS IN THE 700-500MB LAYER WITH A DRY LAYER BELOW...SO -SHRA BASED
THIS LAYER SHOULD AMOUNT TO LITTLE MORE THE SPRINKLES. TEMPERATURES
WERE LEFT UNTOUCHED AT THIS TIME. HIGHS AROUND 60 IN THE SOUTH
SEEMS A BIT OPTIMISTIC...BUT THE CLEARING/WARMER AIR IS WITHIN A
COUNTY OF OUR SOUTHTERN BORDER...CLOSE ENOUGH TO HOLD ON TO THE CURRENT
FORECAST. ALSO THE MID 40S IN THE NORTH THIS AFTERNOON MAY BE ON
THE OPTIMISTIC SIDE WITH A STIFF EAST WIND AND LOW OVERCAST SKIES
THROUGH THE AFTERNOON. DLF
&&
.AVIATION... /ISSUED 706 AM CDT SAT APR 28 2012/
A WEAK LOW PRESSURE SYSTEM PASSING SOUTH OF THE AREA WILL KEEP
WIDESPREAD LOW CLOUDS AND PATCHY LIGHT PRECIPITATION IN PLACE OVER
THE AREA TODAY. IFR CIGS OVER CENTRAL AND WESTERN IA WILL SPREAD
EAST OVER THE CID AND DBQ TERMINALS THIS MORNING AND LINGER THERE
THROUGH MUCH OF THE DAY. THERE WILL ALSO BE PERIODS OF VERY
LIGHT RAIN/DRIZZLE AND FOG THAT WILL REDUCE VISIBILITIES TO 3 TO 5
MILES. CONDITIONS AT BRL AND MLI ARE OPTIMISTICALLY KEPT
MVFR...BUT A PERIOD OF IFR WILL BE POSSIBLE AS WELL. BRISK EAST
WINDS WILL DIMINISH AND LOSE GUSTS BY MID AFTERNOON. MVFR AND
POSSIBLY IFR CIGS WILL REMAIN IN PLACE OVERNIGHT. THERE WILL BE
POTENTIAL FOR SHOWERS TOWARD MORNING AT ESPECIALLY BRL THAT MAY
BE ADDED TO LATER FORECASTS.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
842 PM MDT SUN APR 29 2012
.UPDATE...
ISSUED AT 837 PM MDT SUN APR 29 2012
MADE SOME CHANGES TO THE FORECAST BASED ON LATEST RADAR TRENDS.
HAVE HIGHEST POPS IN EASTER COLORADO AHEAD OF THE UPPER LEVEL
SHORT WAVE TROUGH. OVERNIGHT LATEST NAM AND HRRR HAVE SHIFTED BEST
LIFT NORTH...SO HAVE TRENDED POPS THAT DIRECTION WITH THIS UPDATE.
DID LOWER POPS IN THE SOUTH SOME AS LATEST NAM POINT SOUNDINGS
HAVE DRIED OUT SOME IN THAT AREA. HOWEVER THE LATEST GEFS HAS 80
PERCENT LIKELIHOOD OF PRECIP. FALLING IN THE SOUTHERN CWA...AND
MODELS STILL PLACE THE BULK OF THE ELEVATED INSTABILITY OVER THAT
AREA SO WILL KEEP MENTION OF PRECIP. GOING FOR THE SOUTHERN CWA.
&&
.SHORT TERM...(THIS AFTERNOON THROUGH TONIGHT)
ISSUED AT 1230 PM MDT SUN APR 29 2012
INITIAL SHORT WAVE TROUGH RESPONSIBLE FOR THIS MORNING SHOWERS AS
EXITED CWA AS PER WATER VAPOR IMAGERY WITH PLENTY OF CLEARING
OCCURRING BEHIND IT...WHICH SHOULD ALLOW FOR A FEW HOURS OF
HEATING/DESTABILIZATION TO OCCUR IN ADVANCE OF NEXT PV ANOMALY
MOVING INTO THE AREA LATER THIS AFTERNOON. HAVE SOME CONCERNS THAT
SFC TDS APPEAR TO BE DRIER THAN OPERATIONAL MODELS EXPECTING
RESULTING IN HIGHER CONVECTIVE TEMPS AND CINH VALUES. WHILE NEAR
TERM MODELS CONTINUE TO INITIATE CONVECTION IN THE NEXT FEW
HOURS...BUT WITH SUBSIDENCE BEHIND INITIAL WAVE AND DRIER BOUNDARY
LAYER THINK DELAYING POPS UNTIL LATE AFTERNOON IN ORDER.
EXPECT CONVECTION TO INITIATE ALONG DEVELOPING WARM FRONT ACROSS
SOUTHERN CWA WHERE CONVERGENCE AND INSTABILITY WILL BE MAXIMIZED.
THE EXACT PLACEMENT OF THIS FRONT REMAINS IN QUESTION AS SFC OBS
NOT REALLY SHOWING MUCH OF A RESPONSE TO NEXT SYSTEM YET...BUT
WITH LATEST PRESSURE FALLS ANALYSIS WOULD NOT BE SURPRISED THAT IT
ENDS UP A BIT FARTHER NORTH THAN PREVIOUSLY EXPECTED. WITH EAST
SOUTHEASTERLY WINDS AT THE SFC AND STRONG AND 40 KTS OF WESTERLY
FLOW ALOFT...LONG AND FAIRLY STRAIGHT HODOGRAPHS SUPPORT
ORGANIZED STORMS/SUPERCELLS AND WITH LCLS HIGHER THAN PREVIOUSLY
EXPECTED THINK MOST LIKELY THREAT WILL BE LARGE HAIL. TOUGH TO
REALLY PICK OUT A A LOT OF UPPER LEVEL SUPPORT OVERNIGHT GIVEN
POSITION OF H3 JET AND SHORT WAVE RIDGING BEHIND LATE AFTERNOON
S/W TROUGH BUT MODELS GENERALLY AGREE THAT H85-H7 WAA INCREASES
THROUGH THE EVENING HOURS WITH SUFFICIENT MOISTENING AND
DESTABILIZATION TO SUPPORT SHOWERS AND STORMS THROUGH THE NIGHT.
SOME OF THE MORE AGGRESSIVE MUCAPE FORECASTS SUGGEST A HAIL THREAT
THROUGH THE NIGHT AND WITH SREF MUCAPES CLUSTERING AROUND 1000
J/KG OF CAPE CANNOT RULE THAT OUT. WHILE THERE DOES APPEAR TO BE
PLENTY OF SUPPORT FOR PRECIPITATION WITH AVAILABLE DATA...THE LACK
OF UPPER LEVEL SUPPORT AND CURRENT MODELS OVER FORECASTING SFC
MOISTURE LOWERS CONFIDENCE TO THE POINT WHERE DO NOT THING GOING
ABOVE SCATTERED COVERAGE IS WARRANTED AT THIS MOMENT..AND WILL
GENERALLY FOCUS POPS WHERE ENSEMBLE PROBABILITIES ARE MAXIMIZED
BUT MAY HAVE TO SHIFT THESE NORTH SHOULD A FARTHER NORTH FRONTAL
POSITION MATERIALIZE.
IN ADDITION TO POTENTIAL FOR THUNDERSTORMS...STRONG AGREEMENT THAT
SFC TDS WILL INCREASE THROUGH THE NIGHT WITH A WEAK UPSLOPE
COMPONENT IN THE SFC FLOW. POTENTIAL FOR FOG LOOKS GOOD...WITH
SREF INDICATING HIGH PROBABILITIES OF VISIBILITIES LESS THAN 3
MILES. COULD POTENTIALLY SEE A LARGE AREA OF DENSE FOG...BUT WITH
THUNDERSTORMS LIKELY LIMITING FOG COVERAGE AND DURATION AS THEY
MOVE ACROSS THE AREA...PLAN ON HOLDING OFF ANY KIND OF HIGHLIGHT
AND TEMPERING COVERAGE A BIT.
.LONG TERM...(MONDAY THROUGH SUNDAY)
ISSUED AT 225 PM MDT SUN APR 29 2012
MONDAY-MONDAY NIGHT...FIRST SHORTWAVE TROUGH SHIFTS NORTH AND EAST
OF THE AREA...WITH SHOWERS TAPERING BY MIDDAY MONDAY. A DRYLINE WILL
BEGIN TO MOVE EAST AHEAD OF THE NEXT APPROACHING SHORTWAVE TROUGH
MONDAY AFTERNOON. HIGH TD VALUES ARE ADVISED BY MOST GUIDANCE ACROSS
OUR EASTERN CWA...WITH GOOD INSTABILITY. NAM ALSO SHOWS FAVORABLE
SHEAR PROFILES FOR DISCRETE SUPERCELL DEVELOPMENT EAST OF THIS
DRYLINE IN THE AFTERNOON/EARLY EVENING. IM LESS CERTAIN ABOUT HOW
MUCH LARGE SCALE ASCENT WILL BE IN PLACE ACROSS EASTERN
LOCATIONS...WITH SUBSIDENCE IN THE WAKE OF DEPARTING SHORTWAVE
POSSIBLY LIMITING CONVECTIVE INITIATION UNTIL ALMOST 00Z. FOR NOW I
KEPT A DECREASING TREND IN POPS THROUGH MIDDAY...WITH INCREASING
CHANCES BY AROUND 00Z. BY MONDAY EVENING LARGE SCALE ASCENT/MID
LEVEL MOISTURE AXIS SHIFT WELL EAST OF THE CWA...WITH SUBSIDENCE
BUILDING BACK OVERHEAD...SO I LEFT THE FORECAST DRY AFTER MIDNIGHT.
SURFACE TD REMAIN HIGH ACROSS THE CWA AS DRY LINE MOVES EAST MONDAY
NIGHT...SO CONDITIONS WILL BE PRIMED FOR FOG DEVELOPMENT. QUESTION
WILL BE WHETHER OVERNIGHT WINDS DECREASE ENOUGH. FOR NOW I LEFT FOG
MENTION IN PLACE MONDAY NIGHT...WITH BEST FOG COVERAGE ACROSS THE
NORTHEAST.
TUESDAY-SUNDAY...ECMWF/GFS BOTH SHOW H5 RIDGE DEVELOPING BY LATE
NEXT WEEK ACROSS THE SOUTHERN CONUS...SHIFTING WEST TOWARDS THE
CENTRAL PLAINS. OUR CWA REMAINS IN W/SW FLOW THROUGH THESE
PERIODS...SO WE WILL CONTINUE TO FACE THE SAME PROBLEM OF TIMING OUT
WEAK SHORTWAVE TROUGHS. FOR NOW THURSDAY NIGHT AND FRIDAY ARE THE
ONLY PERIODS THAT I KEPT DRY FOR THE ENTIRE CWA...AND EVEN THEN
THERE HAVE BEEN SEVERAL PAST RUNS SHOWING SMALL CHANCES OVER PARTS
OF THE CWA THOSE DAYS. IN ANY CASE THIS PATTERN IS GOING TO BE
UNSETTLED...WITH ABOVE NORMAL TEMPERATURES AND SPORADIC
THUNDERSTORM CHANCES.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 601 PM MDT SUN APR 29 2012
VFR TO LIFR CONDITIONS ARE FORECAST FOR THE 0Z TAFS. CURRENT RADAR
SHOWS THUNDERSTORMS SOUTH OF INTERSTATE 70 MOVING TO THE EAST.
LATEST GUIDANCE PLACES THE BEST FORCING OVER THOSE AREAS...SO
BELIEVE THUNDERSTORMS SHOULD STAY NEAR TO SOUTH OF KGLD THIS
EVENING THEN MOVE NEAR THE SITE AFTER 6Z. POINT SOUNDINGS FOR KMCK
DO SHOW THE ENVIRONMENT SATURATING DURING THE OVERNIGHT
HOURS...HOWEVER WITH BETTER FORCING AND INSTABILITY FURTHER SOUTH
WILL HOLD OFF PLACING A MENTION OF TS IN THE KMCK TAF FOR NOW.
DURING THE OVERNIGHT HOURS THE LOW LEVELS SATURATE AS HIGHER DEW
POINTS FURTHER EAST ARE ADVECTED INTO THE AREA. CURRENTLY AM
THINKING THE VISIBILITIES WILL BEGIN TO DECREASE AROUND 6Z...WITH
THE LOWEST VISIBILITIES DURING THE OVERNIGHT/EARLY MORNING HOURS.
AM FAIRLY CONFIDENT KMCK WILL HAVE VISIBILITIES OF LESS THAN A
MILE...BUT AM NOT AS SURE FOR KGLD AS MODELS PLACE THE LOW VISIBILITIES
TO EITHER THE NORTH OR EAST. VISIBILITIES WILL IMPROVE DURING THE
MID MORNING HOURS AS TEMPERATURES WARM.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JTL
SHORT TERM...JRM
LONG TERM...DR
AVIATION...JTL
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1214 AM CDT SAT APR 28 2012
...UPDATE TO AVIATION...
.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...
VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD WITH WINDS
TURNING FROM WEST...TO NORTHWEST...TO NORTHEAST BY SATURDAY
AFTERNOON. THERE IS A SMALL CHANCE FOR REDUCED VISIBILITY BETWEEN
09Z AND 13Z...BUT HAVE HIGHER CONFIDENCE IN VFR AT THIS TIME.
BARJENBRUCH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
653 AM EDT SAT APR 28 2012
.Forecast Update...
Issued at 645 AM EDT Sat Apr 28 2012
Band of showers and isolated thunderstorms associated with zone of
isentropic lift over east-central and northern Kentucky continues to
push east and will exit our forecast area in another hour or so.
Meanwhile, additional showers are developing over parts of Illinois
into west-central to southwest Indiana. Most of these should stay
north of our area, but could clip parts of south-central Indiana.
Latest surface warm frontal position is over southwest Kentucky with
a sharp dewpoint change across it (upper 30s and 40s to the north,
and lower 60s to the south of the boundary). The front will continue
to push northeast today.
For this afternoon, 06 UTC model runs and latest HRRR model continue
to support thunderstorm development this afternoon over southern
Indiana and north-central and east-central Kentucky along and near
warm front where best low-level moisture and convergence should be
pooled along. Haved actually increased storm probabilities a bit
this afternoon, especially over east-central Kentucky. Some severe
storms still look like a decent bet with good instability and
low-level lapse rates along with modest shear that should lead to
pulse/multicell storms with hail and possible upgrowth into an MCS
(QLCS) with small scale bowing segments causing potentially damaging
wind gusts in a few spots.
.Short Term (Today through Sunday)...
Issued at 330 AM EDT Sat Apr 28 2012
...Potential for scattered severe thunderstorms this afternoon and
early evening over southern Indiana and northern part of central
Kentucky...
Broad upper low will move into the northern Plains today with
westerly mid-level flow streaking east to the south of the low from
the central U.S. into the Ohio Valley. A warm front at the surface
currently positioned over western Tennessee into Missouri at 07z
will lift northeast today bringing a surge of warmer low-level air
northward across central Kentucky, along with higher surface
dewpoints. The front should reach a line from southern Illinois to
near Louisville to near Lexington around mid afternoon. It will
continue a little farther northeast late this afternoon, but will
then stall given westerly flow aloft and presence of troughing aloft
over the eastern Great Lakes. The front will help focus low-level
moisture convergence and lift in an increasingly unstable air mass
this afternoon. Models suggest a weak shortwave will assist with
convective development this afternoon as well. SPC WRF model showed
convection firing over eastern Missouri and southern Illinois then
tracking east along the warm front into southern Indiana and
north-central and then east-central Kentucky by late afternoon and
early evening.
Model soundings show some elevated instability this morning above
the cooler, more stable boundary layer north of the warm front. This
could lead to scattered showers this morning ver southern Indiana
and parts of the Bluegrass area with some weak isentropic lift. By
this afternoon, with warm frontal passage, low-level lapse rates
will steepen nicely along with some dry air aloft. This is a good
setup for some pulse type severe storms with large hail and local
wind damage, mainly over south-central Indiana and north-central and
eventually east-central Kentucky. Deep-layer shear is modest but
should be enough for possible storm organization, so upscale growth
into a forward propagating convective system with small scale bowing
segments is possible late today as well. South-central Kentucky will
be clearly in the warm sector with less overall forcing and a
slightly more capped air mass. Thus, will forecast only isolated
thunderstorms in this area this afternoon for now.
For tonight, convection will begin to wane with loss of diurnal
heating. Also, the warm front will stall and actually push back
south across central Kentucky bringing cooler, more stable boundary
layer air across southern Indiana and north-central and east-central
Kentucky. There still will remain some elevated instability so can`t
rule out isolated showers/thunderstorms tonight. Low temperatures
will fall into the mid-upper 40s over our northeast forecast area,
with mid-upper 50s over southwest regions south of the front.
For Sunday, the front will be quasi-stationary over central to
south-central Kentucky. Models are tenuous in convective forcing and
axis of moisture. There could be isolated to scattered elevated
showers and storms over southern Indiana and north-central and
east-central Kentucky but difficult to establish trends at this
time. The best location for scattered convection Sunday afternoon
appears to be near the front over central or south-central Kentucky,
if there is enough low-level moisture convergence to overcome the
convective cap during the day. If cells develop near the front
Sunday, isolated strong storms again could occur, but the severe
potential will be lower than later this afternoon over northern
areas. High temperatures Sunday may vary considerably on both sides
of the front, with upper 60s and lower 70s north to the lower to mid
80s south.
.Long Term (Sunday Night through Friday)...
Issued at 335 AM EDT Apr 28 2012
Sunday Night through Tuesday Night...
By Sunday night, both the GFS and Euro solutions suggest that
mid-level ridging will build sharply across the Ohio Valley in
response to two troughs to our NW and to our NE. At the surface, a
warm frontal boundary should be located to our north. The ridging
looks to hold into the day on Monday which should keep the area
fairly dry. Can`t rule out isolated showers or storms Sunday night
and Monday, but feel that the best chances will be to our north
along the aforementioned warm front. A series of weaker mid-level
waves will knock down this mid-level ridge axis and along a frontal
boundary to settle into the area for Tuesday and Tuesday night.
Appears that the best chances for storms will during the afternoon
hours on Tuesday. Looking at model soundings and vertical wind
profiles reveal a strong instability, low shear environment
suggestive of multicellular pulse convection. Convection should
diminish and move off to the east Tuesday night as the mid-level
wave gets shunted off to the east and the mid-level heights quickly
rebuild across the region. Will plan on keeping high chance PoPs in
the forecast for Tuesday afternoon and then decreased them with time
Tuesday night.
Temperatures through the period are expected to remain above normal
for this time of the year. This agrees well with the latest
ensemble anomalies which suggest temps running about 5-8 degrees
above normal. Lows Sunday night will drop into the the lower-mid
50s with highs on Monday warming into the 75-80 degree range. Lows
Monday night will not cool off as much with readings generally in
the lower 60s. Highs on Tuesday will warm back into the 75-80
degree range with lows Tuesday night cooling back into the lower to
middle 60s.
Wednesday through Friday...
For the Wednesday through Friday period, the GFS and Euro suggest
above normal 500 hPa heights across the eastern third of the
country. Both the 28/00Z GFS and Euro deterministic runs develop a
rather large upper ridge across the southeastern US in the Wed/Thu
time frame. Both models generally flatten this ridge toward the end
of the week as a series of weaker disturbances attempts to bring
more of a zonal upper pattern back to the CONUS. The 28/00Z GFS
solutions are more aggressive/progressive with the breakdown of the
ridge. However, this is a typical bias of the GFS in the long term
and am more inclined to go with the slower/conservative Euro which
maintains better continuity with the existing forecast for the
Wed/Thu time frame. Signals within the data are starting to appear
that the ridge will likely break down by the weekend and the Ohio
Valley may get itself into a northwesterly flow type pattern that
could set us up for multiple rounds of convection as we move into
next weekend.
With the ridge axis expected to be closest to us on Wednesday, this
day would appear to be the driest of the period. Isolated-scattered
diurnally driven convection will be possible on Thursday and more
likely as we get into Friday. Given the anticipated setup, a strong
moderation in temperatures is likely from Wednesday into Friday.
Along with the rising temperatures will be a dramatic increase in
dewpoint. In fact, current data signals would suggest downright
warm/muggy conditions as we head toward the end of the week.
Daytime highs will likely run in the 80-85 degree range through the
period with overnight lows only cooling into the low-mid 60s.
&&
.Aviation (12Z TAF Issuance)...
Updated at 650 AM EDT Sat Apr 28 2012
Sky cover has been variable early this morning ranging from cloudy
to mostly clear. A zone of low clouds from 3-4 kft developed over
central Kentucky overnight and is now pushing through east-central
Kentucky, including LEX. These clouds should continue east leaving
only scattered to perhaps broken low clouds (but still VFR) for the
rest of the morning. Winds will continue from the east and southeast
this morning before veering to south and southwest this afternoon as
a warm front moves through. It will move through BWG this morning
and by mid or late afternoon at LEX and SDF, but will stall just
north of SDF. Scattered to numerous thunderstorms still expected by
mid and late afternoon along and near front, potentially affecting
SDF and LEX the most between about 20 UTC and 02 UTC. BWG should see
isolated storms at most. Conditions expected to remain VFR except
temporarily MVFR during storms.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........TWF
Short Term.......TWF
Long Term........MJ
Aviation.........TWF
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
200 AM EDT SAT APR 28 2012
.UPDATE...
ISSUED AT 200 AM EDT SAT APR 28 2012
MADE JUST A FEW ADJUSTMENTS TO THE PRE-DAWN FORECAST...MAINLY TO
LOWER POPS AS THE AREA REMAINS TOO DRY FOR ANY LIGHT RETURNS TO MAKE
IT TO THE SFC AND MEASURE. ALSO UPDATED THE T AND TD GRIDS FOR THE
LATEST OBS AND TRENDS.
UPDATE ISSUED AT 1053 PM EDT FRI APR 27 2012
THE WARM FRONT REMAINS POISED ACROSS THE TENNESSEE VALLEY. THIS WILL
BEGIN TO LIFT TO NORTH BETWEEN 06 AND 12Z...LIKELY STALLING ACROSS
THE MIDDLE OF EASTERN KENTUCKY DURING THE DAY ON SATURDAY. THE LATEST
00Z NAM IS SHOWING A LITTLE BIT OF PRECIPITATION ACROSS THE AREA
BETWEEN 09 AND 12Z...MOST LIKELY IN RESPONSE TO SOME ISENTROPIC LIFT
IN THE 700-800 MB LAYER ONCE AGAIN. THERE IS A LITTLE ELEVATED
INSTABILITY ASSOCIATED WITH THIS...HOWEVER THE SOUNDINGS LOOK
MARGINAL FOR THUNDER...SO WILL CONTINUE TO ONLY MENTION A FEW
SHOWERS. ONCE THIS FORCING RELAXES DURING SATURDAY MORNING...THERE
SHOULD BE A PRETTY GOOD LULL IN THE ACTIVITY UNTIL THE AFTERNOON
HOURS AS WE REMAIN CAPPED. AS SUCH...ADJUSTED SOME OF THE POPS DOWN A
BIT THROUGH SATURDAY MORNING...BEFORE RAMPING BACK UP DURING THE
AFTERNOON...AS A WEAK SHORT WAVE TROUGH APPROACHES OVER TOP THE
LINGERING SURFACE BOUNDARY. FORECAST LOWS RANGING FROM THE LOWER TO
MIDDLE 40S IN THE MORE SHELTERED VALLEYS IN FAR NORTHEASTERN
KENTUCKY...TO THE LOWER TO MIDDLE 50S WEST OF I-75 LOOK ON
TARGET...AND HAVE ONLY MADE SOME MINOR DIURNAL ADJUSTMENTS ACCORDING
TO THE LATEST OBSERVATIONS.
UPDATE ISSUED AT 753 PM EDT FRI APR 27 2012
AN AREA OF WEAKENING CONVECTION IS CURRENTLY MOVING ACROSS SOUTH
CENTRAL KENTUCKY. THIS APPEARS TO BE ASSOCIATED WITH SOME ISENTROPIC
LIFT IN THE 800-700 MB LAYER. THE HRRR MODEL WAS PICKING UP ON THIS
ACTIVITY FAIRLY WELL...DIMINISHING IT AS IT MOVES INTO EASTERN
KENTUCKY. LOCATIONS WEST OF I-75 MAY SEE A FEW SPRINKLES OUT OF
THIS...HOWEVER WITH SUCH DRY LOW LEVEL AIR IN PLACE...WOULD NOT
EXPECT ANYTHING MORE THAN THAT. FRESHENED UP THE REST OF THE HOURLY
DATA AND TRIED TO ACCOUNT FOR A LITTLE SHARPER TEMPERATURE DROP IN
THE NORTHEAST VALLEYS WITH AT LEAST MOSTLY CLEAR TO PARTLY CLOUDY
SKIES EXPECTED INTO EARLY THIS EVENING. WILL REASSESS THE FORECAST
LOWS AS WELL AS IF ANY CONVECTION CAN FIRE UP TOWARDS DAWN
ASSOCIATED WITH THE RETURN OF THE WARM FRONT A BIT LATER ON.
&&
.SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT)
ISSUED AT 307 PM EDT FRI APR 27 2012
SFC ANALYSIS AT 18Z SHOWS YESTERDAY/S COLD FRONT TEMPORARILY RESIDES
ACROSS THE DEEP SOUTH AS A QUASI STATIONARY BOUNDARY...WITH AN
INVERTED TROF ALONG THE FRONT RANGE OF THE ROCKIES. THESE TWO
FEATURES WILL BECOME THE MAIN PLAYERS FOR OUR WX OVER THE SHORT TERM
AS THE FRONT BEGINS TO LIFT BACK TO THE NORTH TONIGHT IN RESPONSE TO
AN AREA OF LOW PRESSURE EJECTING OUT OF THE ROCKIES AND INTO THE
CENTRAL PLAINS. TEMPS TONIGHT WILL BE SOMEWHAT CHALLENGING WITH
ANTICIPATED CLOUD COVER RETURNING FROM THE SOUTH ALONG WITH WARMER
AIR ADVECTING INTO THE REGION...AND UPPER 40S IN THE NORTH TO LOW 50S
IN THE SOUTH WILL NOT QUITE TELL THE WHOLE STORY AS LOWS COULD BE
REALIZED EARLY BEFORE TEMPS LEVEL OFF OR EVEN BEGIN TO CREEP BACK UP
AFTER MIDNIGHT...ESPECIALLY IN THE SOUTH.
12Z MODELS CONTINUE TO DEPICT DECENT ISENTROPIC ASCENT ALONG THE
BOUNDARY AS IT PUSHES NORTH INTO THE REGION LATER TONIGHT...HOWEVER
THE MODELS ARE NOT BEING VERY GENEROUS WITH THE DEEPER MOISTURE. FCST
SOUNDINGS POINT TOWARDS A CONSIDERABLE DRY LAYER BETWEEN H9 AND H7
THRU MOST OF THE OVERNIGHT AND IF PUSH CAME TO SHOVE...CURRENT PROGS
WOULD NOT REALLY SUPPORT ANY PRECIP THRU 12Z BUT WITH A RETURN FLOW
REGIME COMMENCING AND A LEGITIMATE BOUNDARY EXPECTED TO BEGIN NOSING
INTO THE AREA...WILL KEEP ISOLATED SHOWERS IN THE MIX FOR TONIGHT.
BETTER MID AND UPPER LEVEL DYNAMICS LOOK TO ARRIVE ON SATURDAY WITH A
MODEST 50 TO 60 MPH MID AND UPPER LEVEL JET OVERHEAD ALONG WITH A MID
LEVEL IMPULSE SCOOTING ALONG THE OHIO VALLEY AS THE WEAKENING SFC LOW
DRIFTS INTO THE MIDWEST...PULLING THE WARM FRONT FURTHER NORTH
TOWARDS...AND POSSIBLY ACROSS THE OHIO RIVER. PARTIALLY CLEARING
SKIES FROM SOUTH TO NORTH WILL LEAD TO INCREASING INSTABILITY THROUGH
THE LATE MORNING AND EARLY AFTERNOON AS TEMPS REBOUND INTO THE MID
AND UPPER 70S WITH DEW PTS MOISTENING INTO THE MID 50S. MODELS HAVE
BEEN CONSISTENTLY ADVERTISING ALL OF THE NECESSARY INGREDIENTS FOR
DMC WITH A POTENTIAL FOR SOME STRONG TO SEVERE TSTMS DURING THE LATE
AFTERNOON AND EVENING. LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN
THREATS WITH ANY STORMS ON SATURDAY AFTERNOON...AND SPC HAS A GOOD
HANDLE ON ALL OF THIS WITH MOST OF ERN KY HIGHLIGHTED IN THE DY2.
CONVECTION SHOULD BEGIN TO LOOSE SOME OF ITS TEETH OVERNIGHT WITH THE
LOSS OF DAYTIME HEATING...THOUGH THE POTENTIAL FOR OUTFLOW BOUNDARIES
LOITERING ABOUT THE AREA OVERNIGHT SHOULD BE ENOUGH TO WARRANT A
THREAT FOR SCATTERED SHOWERS ALONG WITH ISOLATED RUMBLES THROUGH THE
REMAINDER OF THE NIGHT.
.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 307 PM EDT FRI APR 27 2012
ON SUNDAY THE UPPER AIR STARTS OUT IN AN OMEGA LIKE PATTERN WITH AN
UPPER LOWS OVER THE WESTERN DAKOTAS AND NORTHEAST CANADA WITH A RIDE
EXTENDING FROM A HIGH OVER THE FLORIDA PANHANDLE EXTENDING NORTH
ACROSS INDIANA AND WISCONSIN AND THEN ENDING OVER NORTHERN MANITOBA.
THE PATTERN THEN TRIES TO MORPH INTO A ZONAL PATTERN. THE BOTTOM
LINE IS THAT THE STORM TRACK STAYS OVER OR NEAR THE AREA THROUGH THE
PERIOD. SO CONFIDENCE IS FAIRLY HIGH THAT THIS WILL BE A GENERALLY
ACTIVE WEATHER PATTERN WITH FREQUENT FRONTS AND TROUGHS MOVING
ACROSS THE AREA. THE HARD PART IS THE TIMING AND THIS IS WHERE THE
MODELS DIVERGE. IN ZONAL PATTERNS...SMALL SPEED DIFFERENCES CAN HAVE
GREAT DIFFERENCES IN TIMING.
IN GENERAL TRENDED THE MODEL BLEND TOWARD THE TIMING OF THE ECMWF.
WITH GREATER CONFIDENCE IN THE TIMING...THERE WOULD HAVE BEEN MORE
DRY PERIODS IN THE FORECAST...HOWEVER WITH THE TIMING
DIFFERENCES...SOME OF THE SYSTEMS TENDED TO BLUR TOGETHER. AFTER
SUNDAY...EASTERN KENTUCKY WILL BE IN THE WARM SECTOR AND
TEMPERATURES WILL STAY AT OR ABOVE NORMAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 200 AM EDT SAT APR 28 2012
VFR CONDITIONS SHOULD HOLD FOR THE BULK OF THE CWA THROUGH AT LEAST
DAWN...AS MAINLY MID AND HIGH LEVEL CLOUDS ADVECT IN FROM THE WEST. A
WARM FRONT WILL ENCROACH THE AREA FROM THE SOUTHWEST TOWARDS
DAWN...BRINGING IN LOWER CLOUD COVER...ALTHOUGH STILL GENERALLY ABOVE
3K FEET. THERE MAY BE SOME SCATTERED CONVECTION ASSOCIATED WITH THIS
AS IT MOVES NORTHEAST ACROSS THE FORECAST AREA...HOWEVER WILL
CONTINUE TO ONLY MENTION VCSH THROUGH 15Z AT THIS TIME. WINDS WILL
SHIFT TO THE SOUTHWEST BEHIND THE WARM FRONT AND BECOME GUSTY DURING
THE DAY. EXPECT ADDITIONAL SCATTERED STRONGER CONVECTION TO FIRE UP
IN THE AFTERNOON...PARTICULARLY NORTH OF THE MOUNTAIN PARKWAY...BUT
OUTFLOWS AND NEW DEVELOPMENT COULD IMPACT LOCATIONS FURTHER SOUTH
LATER IN THE AFTERNOON AND EARLY EVENING. FOLLOWING SUNSET THE WINDS
WILL SETTLE TO LIGHT AND VARIABLE IN MOST PLACES.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...MB
LONG TERM....JJ
AVIATION...GEOGERIAN/GREIF
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
106 AM EDT SAT APR 28 2012
.Forecast Update...
Issued at 1245 AM EDT Sat Apr 28 2012
Sky cover has become variable across central Kentucky and southern
Indiana at this time, with skies ranging from mostly cloudy
(mid-high clouds) in east-central Kentucky to mostly clear over
parts of the remainder of central Kentucky. A generic partly cloudy
should due for the rest of the night as mid and high level clouds
remain transitory across the area. Showers have dissipated over the
lower Ohio Valley at this time. There could be isolated showers
develop toward morning, especially along and north of the Ohio River
elevated above the warm front. A better chance for precipitation
will wait til Saturday afternoon. Current hourly temperatures and
lows temperatures seem on track for now.
.Forecast Update...
Issued at 1057 PM EDT Apr 27 2012
Isentropic lift is currently generating some light showers across
the Ohio Valley. However, with dry air at low levels, only a few
isolated sprinkles will be possible. This will occur across mainly
the Bluegrass region for the next few hours. Then expect a dry
period before the next upper wave approaches from the west. This
should begin to spread precip into the Ohio Valley around the 08-09Z
time frame. The HRRR had a good handle on the afternoon/evening
precip in our south, and also depicts scattered showers mainly along
and north of the Ohio River arriving in the pre-dawn hours. Have
adjusted PoPs accordingly. Think the chance of thunder is very
minimal overnight, so have pulled it from the products. Updated
products have been issued.
Update issued at 645 PM EDT Apr 27 2012
Band of showers and thunderstorms are entering our western CWA. Have
increased PoPs across the west, with emphasis on our southwest.
Overall precip is diminishing and starting to dive southeast. Expect
scattered showers and thunderstorms across our southwest, with rain
showers and isolated thunder more likely further north. Then,
chances seem to become less as the precip shield behind this band
has diminished somewhat. Tried to reflect this over the next few
hours with the hourly grids. Updated products have been issued.
.Short Term (Tonight through Saturday night)...
Issued at 300 PM EDT Apr 27 2012
Low pressure over Kansas this evening will progress east into
northern Missouri by morning, lifting a warm front northward across
Tennessee. Showers and thunderstorms were occurring from the Plains
to the Ozarks ahead of this system Friday afternoon, and will move
to the northeast tonight. It appears that the bulk of the rain will
stay north of the Ohio River, where there will be stronger forcing
and deeper moisture. The best chance of showers in the LMK CWA will
be between 4am and 9am along and north of the river.
During the day Saturday the low will advance to the Louisville area
by evening and will pull its warm front up to about Interstate 64.
We should see a break in the precipitation after the morning
activity moves out and before any redevelopment occurs later in the
day. There is some question concerning storms tomorrow. Southern
Kentucky looks to stay well capped, and northern sections of the CWA
will stay capped through much of the day, until late in the
afternoon at Louisville and early evening at Lexington. Winds aloft
aren/t very strong, and the capping plus widespread leftover clouds
in the north behind the departing morning showers may hinder
destabilization. Deep moisture is somewhat lacking as well. At any
rate, it should take until late afternoon before storms can start to
reform. Hail looks to be the main threat from any storms, with wet
bulb zero heights around nine or ten thousand feet.
Shower and thunderstorm chances will continue into the evening hours
before diminishing late Saturday night. The warm front will likely
remain in the general vicinity.
Lows tonight should range from the upper 40s northeast to middle 50s
southwest. Highs tomorrow will be tricky with the front draped
right across the area...right now we`re going for lower 70s in the
north and lower 80s near the Tennessee border. Lows Saturday night
will be in the 50s.
.Long Term (Sunday through Friday)...
Issued at 300 PM EDT Apr 27 2012
By Monday night a ridge of high pressure will park itself over the
southeast United States, extending east into the Atlantic. This
will cause a persistent northerly flow of warm, moist air from the
Gulf of Mexico into the Tennessee and Ohio Valleys. Various
difficult-to-time disturbances both at the surface and aloft will
cross from the Plains into the northeastern U.S. and interact with
the moisture throughout the week and into the weekend, resulting in
a broken record forecast of scattered showers and storms throughout
the period. The week won`t be a washout...just occasional waves
of scattered convection.
The work week will be warm with highs in the 70s/80s Monday/Tuesday
and securely into the 80s from Wednesday into the weekend.
&&
.Aviation (06Z TAF Issuance)...
Updated at 100 AM EDT Sat Apr 28 2012
Skies at 05 UTC ranged from mostly cloudy over east-central Kentucky
to mostly clear over parts of the rest of central Kentucky. Clouds
were mid and high level causing little concern for aviation
purposes. Showers have dissipated at this time, and only isolated
showers appear possible the remainder of the night. Weak easterly
surface winds will continue north and east of the warm front.
On Saturday, warm front is expected to lift slowly northeast across
central Kentucky. Scattered thunderstorms are expected along and
near the front, with SDF and LEX having the best chance for
convection, especially in the afternoon to early evening. Conditions
should remain VFR at all TAF sites throughout the forecast period,
except temporarily MVFR in any thunderstorms.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........TWF
Short Term.......13
Long Term........13
Aviation.........TWF
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1113 AM EDT SAT APR 28 2012
.SYNOPSIS...
LOW PRESSURE MOVING ALONG A FRONTAL BOUNDARY WILL BRING RAIN BACK
INTO THE AREA FOR THIS AFTERNOON AND TONIGHT. HIGH PRESSURE WILL
THEN BUILD IN FROM THE NORTHWEST AND ALLOW FOR A DRY SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
15Z ENHANCED SHORT TERM FORECAST UPDATE HAS BEEN ISSUED TO REDUCE
POPS IN A BREAK IN PRECIP WITH MID-LEVEL DRYING PRIOR TO THE NEXT
SHORT WAVE REACHING THE AREA AROUND 18Z. IN ADDITION, MENTION OF
ISOLATED FLURRIES HAS BEEN FOR THE PITTSBURGH METRO AND AREAS
NORTH AND EAST.
THE LATEST RUC MID-LEVEL ANALYSIS INDICATES THE UPPER OHIO VALLEY IN
A NEARLY ZONAL FLOW. AN INITIAL SHORT WAVE IS PUSHING SOUTHEAST OF
THE AREA AND ASIDE FROM A FEW LOCATIONS REPORTING LIGHT SPRINKLES
AND FLURRIES, REFLECTIVITY INDICATED BY KPBZ HAS BEEN VIRGA WITH
15-20 TD DEPRESSIONS AT THE SURFACE.
AN AREA OF MID-LEVEL DRYING WILL MOVE ACROSS THE AREA, ALLOWING
FOR A BREAK IN PRECIP INTO THE EARLY AFTERNOON. THE NEXT SHORT WAVE,
MOST EVIDENT IN THE 925-750MB LAYER WILL CONTINUE TO RIDE NORTH OF A
FRONTAL BOUNDARY AND BRING SHOWERS TO THE AREA AFTER 18Z. UPSTREAM
NLDN STRIKES, WEAK ELEVATED INSTABILITY WITH THE WAVE AND THE FRONTAL
BOUNDARY CREEPING NORTHWARD INTO NORTH-CENTRAL WV HAVE LED TO THE
ADDITION OF A SCHC OF THUNDER INTO THE EVENING FOR THE FAR SOUTHERN
ZONES.
THERE IS SOME UNCERTAINTY WITH THE TEMP FORECAST THIS AFTERNOON
DEPENDING ON HOW FAR NORTH THE BOUNDARY MAKES IT. FORECAST IS
CLOSEST TO A LAMP/HRRR BLEND, WITH HIGHS RANGING FROM NEAR 60 ACROSS
NORTH-CENTRAL WV TO THE MID 40S NORTH OF PITTSBURGH.
MODELS DO DIFFER SOMEWHAT TONIGHT WITH PLACEMENT OF FRONT AS IT
PUSHES BACK SOUTH BEHIND SHORTWAVE. BLEND SOLUTION LEAVES CHANCE
POPS ACROSS THE SOUTHEAST RIDGES UNTIL LATE NIGHT WITH REMAINDER OF
REGION DRYING OUT. WITH CLEARING SKIES AND COLD ADVECTION ANOTHER
FREEZE IS PROBABLE, ESPECIALLY ACROSS THE NORTHERN AREAS AND THUS A
FREEZE WATCH REMAINS IN EFFECT.
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY NIGHT/...
THE FRONTAL BOUNDARY WILL RETREAT SOUTHWARD ON SUNDAY AS HIGH
PRESSURE BUILDS IN FROM THE UPPER GREAT LAKES. THIS WILL ALLOW FOR
A DRY FORECAST SUNDAY THROUGH MUCH OF THE DAY MONDAY. THAT SAME
BOUNDARY WILL BEGIN TO LIFT BACK NORTHWARD INTO THE AREA AS A WARM
FRONT LATE ON MONDAY, RETURNING THE CHANCE OF SHOWERS AND
THUNDERSTORMS IN THE EVENING AS SURFACE-BASED INSTABILITY
INCREASES. THE CHANCE OF THUNDERSTORMS WILL CONTINUE INTO TUESDAY
NIGHT WITH WARM AIR ADVECTION ONGOING. TEMPERATURES WILL BE
PROGRESSIVELY WARMER EACH DAY, WARMING FROM AROUND 5 DEGREES BELOW
NORMAL ON SUNDAY TO 5-10 DEGREES ABOVE NORMAL BY TUESDAY.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
MODELS CONTINUE TO INDICATE EVOLUTION OF A FLAT RIDGE UPPER FLOW
PATTERN OVER THE ERN CONUS AS TROUGH CROSSES THE WEST ON WEDNESDAY.
TEMPERATURE MODERATION MAY THUS BE ANTICIPATED IN THE WARM ADVECTION
REGIME IN ADVANCE OF THAT SYSTEM...PERHAPS TO AS MUCH AS 10
DEGREES ABOVE THE SEASONAL NORMALS.
PRECIPITATION POTENTIAL WILL INCREASE ON THURSDAY...AND CONT INTO
FRIDAY AS THAT TROUGH IS PROGGED TO ADVANCE ACRS THE GREAT LAKES
AND PULL A COLD FRONT TOWARD THE UPPER OHIO REGION. CURRENT TIMING
SUGGESTS THE FRONT WILL BE CLEAR OF THE AREA BY FRIDAY...HENCE POP
NUMBERS AND TEMPERATURES WERE REDUCED FOR THE WEEKEND.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
MID LEVEL CLOUDS BLANKETED THE UPR OH REGION THIS MORNING WITH THE
WARM...MOIST ADVECTION IN ADVANCE OF MIDWRN SHORTWAVE. THE DRY
LAYER UNDER 10 KFT IS FORECAST TO BE OVERCOME WITH THE ADVANCE OF
THAT SYSTEM AND AREAS OF MVFR ARE ANTICIPATED BY EVE...ESPECIALLY
OVR SOUTHERN TERMINALS AS WARM FRONT LIFTS TOWARD THOSE PORTS.
CONDITION DEGRADATION WL BE BRIEF THOUGH AS DRY HIGH PRES IS
PROJECTED TO QUICKLY REBUILD OVR THE REGION ON SUNDAY.
.OUTLOOK...SUNDAY THROUGH WEDNESDAY...
SURFACE RIDGE SHOULD CONT TO PROVIDE VFR CONDITIONS INTO MONDAY.
RESTRICTIONS ARE POSSIBLE AGAIN LATE MONDAY...AND INTO WEDNESDAY AS
LOW PRES IS FORECAST TO APPROACH AND CROSS THE UPPER OHIO VALLEY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...FREEZE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
OHZ041.
PA...FREEZE WATCH FROM LATE TONIGHT THROUGH SUNDAY MORNING FOR
PAZ007>009-013>016-020-022-023.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
829 PM EDT SUN APR 29 2012
.SYNOPSIS...
ISSUED AT 305 PM EDT SUN APR 29 2012
HIGH PRESSURE WILL MOVE EAST AND A WARM FRONT WILL PUSH NORTH
TOWARDS SOUTHERN LOWER MICHIGAN TONIGHT. SOME SHOWERS AND
THUNDERSTORMS WILL BE ARRIVING AFTER MIDNIGHT TONIGHT THEN SPREAD
NORTH ON MONDAY. WARMER TEMPERATURES ALONG WITH SCATTERED SHOWERS
AND THUNDERSTORMS CAN BE EXPECTED FROM TUESDAY THROUGH THURSDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 305 PM EDT SUN APR 29 2012
AREA OF ISENTROPIC ASCENT NORTH OF SFC WARM FRONT IS GENERATING
RAIN ACROSS ILLINOIS THIS AFTERNOON. THIS WILL CONTINUE NORTHEAST
AND EDGE INTO FAR SOUTHWEST LOWER MICHIGAN THIS EVENING. LEADING EDGE
WILL HAVE TO OVERCOME DRY AIR INITIALLY BUT 12Z MODEL RH PROFILES
AND HRRR RUC INDICATE THE DRY AIR WILL BE OVERCOME AS LOW LEVEL
FLOW GOES SOUTHEAST WITH THE SFC RIDGE MOVING EASTWARD.
WILL BRING CHANCE POPS IN THIS EVENING AND THEN EXPAND NORTHWARD
AFTER MIDNIGHT. WILL HAVE THUNDERSTORMS ACROSS THE SOUTHERN
FORECAST AREA AS POTENTIAL FOR ELEVATED CONVECTION EXISTS WITH
TOTAL TOTALS IN THE UPPER 40S. MAIN SLUG OF QPF MOVES EAST DURING
THE DAY ALONG WITH DEEP MOISTURE...WHICH MEANS LIKELY POPS IN THE
MORNING FOLLOWED BY CHANCE POPS IN THE AFTERNOON.
MAX TEMPS WILL BE TRICKY ON MONDAY AS MODEL RH PROFILES SUGGEST
LOWER CLOUDS WILL STICK AROUND ALL DAY...AND UPSTREAM OBS IN THE
CLOUDS NORTH OF THE WARM FRONT THIS AFTERNOON ARE CURRENTLY STUCK
IN THE 40S. WENT A BIT BELOW GUIDANCE FOR MONDAY MAXES.
MONDAY NIGHT WILL SEE LOW CLOUDS DECREASE AS WEAK SFC RIDGING
BUILDS IN. WILL GO WITH A DRY FORECAST AS DEEP MOISTURE HAS
DEPARTED BY EVENING. GUIDANCE TEMPS HAVE TRENDED DOWNWARD AND SO
TWEAKED MINS LOWER.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 305 PM EDT SUN APR 29 2012
THE MAIN LONG TERM FCST CHALLENGE CONTINUES TO INVOLVE DETERMINING
PROBABILITIES FOR RAIN AND CONVECTION THROUGH MOST OF THE LONG RANGE
FCST PERIOD.
A WEAK HIGH PRESSURE RIDGE WILL PRODUCE DRY WX THROUGH AT LEAST
MIDDAY TUESDAY. WE WILL MAINTAIN MENTION OF A CHC OF SHOWERS/STORMS
OVER OUR SOUTHERN FCST AREA TUESDAY AFTERNOON AS THE WARM FRONT
LIFTS NORTH. IT WILL BE MILDER TUESDAY WITH MAX TEMPS REACHING THE
LOW TO MID 70S. SHOWERS AND A FEW TSTORMS ARE ANTICIPATED TUESDAY
NIGHT AS THE WARM FRONT CONTINUES TO LIFT NORTHWARD.
THE MODERATING TREND WILL CONTINUE WEDNESDAY WITH OUR FCST AREA
SOLIDLY IN THE WARM SECTOR WITH MAX TEMPS REACHING THE UPPER 70S TO
LOWER 80S. WE WILL MAINTAIN CHC POPS FOR SHOWERS/TSTORMS WEDNESDAY
AS MODERATE INSTABILITY DEVELOPS IN THE WARM SECTOR. HOWEVER I AM
NOT CONVINCED THAT THERE WILL BE A GOOD TRIGGERING MECHANISM/FOCUS
FOR CONVECTIVE INITIATION TO OCCUR. MOST OF THE DAY WILL LIKELY BE
DRY. 12Z GFS GUIDANCE SUGGESTS THE BETTER CONVECTIVE POTENTIAL
WEDNESDAY AFTERNOON WILL BE MUCH FURTHER NORTH NEAR THE WARM FRONT
AND ALSO WELL TO OUR NW IN CLOSER PROXIMITY TO THE SFC LOW OVER THE
UPPER MIDWEST.
THE WEDNESDAY NIGHT TIME FRAME REMAINS FAVORED FOR CONVECTIVE
DEVELOPMENT DUE LARGELY TO FORCING FROM A 35 TO 45 KT LLJ. 1000-850
MB MOISTURE TRANSPORT ALSO LOOKS FAVORABLE BY WEDNESDAY EVENING.
SHOWERS AND TSTORMS WILL LIKELY LINGER/REDEVELOP ON THURSDAY WITH
SHOWERS LINGERING FRIDAY BEFORE A COOLER AND DRIER AIRMASS ADVECTS
FOR THE WEEKEND WITH TEMPS RETURNING TO NEAR NORMAL BY THEN.
CANNOT RULE OUT A FEW STRONG TO SEVERE STORMS LATE WEDNESDAY THROUGH
THURSDAY AS INSTABILITY INCREASES ALONG WITH BRIEFLY STRONGER
FORCING FROM THE LLJ. HOWEVER WE CONCUR WITH THE PREVIOUS SHIFT THAT
THE OVERALL SEVERE WX THREAT MIDWEEK LOOKS FAIRLY LOW DUE TO SEVERAL
LIMITING FACTORS INCLUDING WEAK DEEP LAYER SHEAR STAYING GENERALLY
UNDER 30 KTS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 828 PM EDT SUN APR 29 2012
A SURGE OF MOISTURE ALONG AND AHEAD OF A WARM FRONT WILL LEAD TO
LOWERING CEILINGS TONIGHT AS WELL AS THE DEVELOPMENT OF RAIN.
RAIN WAS SPREADING ACROSS SOUTHERN LAKE MICHIGAN AT 800PM AND INTO
SOUTHWEST LOWER MICHIGAN.
EXPECT RAIN TO SPREAD INTO THE TAF SITES IN THE NEXT 2 TO 4
HOURS...WITH VFR CEILINGS HOLDING FIRM. CONDITIONS WILL DROP INTO
THE MVFR CATEGORY OVERNIGHT...AFTER 06Z. A GOOD BATCH OF RAIN
SHOULD MOVE THROUGH THE TAF SITES BETWEEN 03Z AND 10Z. CEILINGS
WILL DROP INTO AND LIKELY HOLD IN THE 1000-2000FT RANGE ON MONDAY.
SOME DRIZZLE AND FOG WILL LINGER THROUGH THE AFTERNOON. A CHANCE
FOR A FEW THUNDERSTORMS EXISTS OVERNIGHT FROM KAZO TO KJXN.
&&
.MARINE...
ISSUED AT 305 PM EDT SUN APR 29 2012
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
TUESDAY. THUNDERSTORMS ARE POSSIBLE SOUTH OF MUSKEGON ON MONDAY.
&&
.HYDROLOGY...
ISSUED AT 305 PM EDT SUN APR 29 2012
HEAVY RAIN IS POSSIBLE WEDNESDAY AND THURSDAY WHICH COULD LEAD TO
RISES ON THE RIVERS BY THE END OF THE WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...DUKE
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1214 PM CDT SAT APR 28 2012
.DISCUSSION...
CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSIS SHOW AN
AMPLIFIED AND VISUALLY CONVOLUTED PATTERN ACROSS THE CONTINENT AT
THE CURRENT TIME. A CUTOFF UPPER LOW CIRCULATING OVER THE NORTHERN
ROCKIES IS WORKING TO EJECT A SHORTWAVE NORTH INTO SOUTHERN
MINNESOTA... WHICH IS HELPING TO PRODUCE THE BAND OF SHRA ACROSS
THE SOUTHERN PART OF THE FORECAST AREA AT THE CURRENT TIME.
HOWEVER... THIS FEATURE IS RUNNING INTO THE UPPER RIDGE WHICH
EXTENDS FROM CENTRAL SASKATCHEWAN SOUTHEAST THROUGH WISCONSIN...
WHICH IS SHEARING IT OUT WITH TIME AND WORKING TO DIMINISH THE
PCPN AS IT WORKS NORTHWARD. A SECONDARY SURGE OF PCPN WITH THE
UPPER TROUGH TO OUR SOUTH... COINCIDENT WITH BETTER MID-LEVEL
INSTABILITY... IS IN IOWA AND IS ALSO WORKING NORTHWARD WITH TIME.
THE LATEST HRRR AND HIGH RESOLUTION WINDOW RUNS SEEM TO HAVE A
DECENT HANDLE ON ALL OF THIS ACTIVITY... AND SUGGEST IT SHOULD
CONTINUE TO WORK UP INTO THE FORECAST AREA THIS MORNING INTO EARLY
AFTERNOON... WITH ITS NORTHERN EDGE HAVING A TOUGH TIME MAKING IT
INTO THE NORTH CENTRAL AND NORTHEAST PORTION OF THE AREA GIVEN DRY
LOW LEVEL AIR BACK-FEEDING INTO THE REGION FROM THE SURFACE HIGH
POSITIONED TO OUR EAST. AS FAR AS THE LARGE SCALE PATTERN GOES...
OVERALL IT LOOKS TO DE-AMPLIFY AS WE HEAD INTO THE EARLY PART OF
NEXT WEEK... AS THE UPPER LOW TO OUR WEST SLIDES NORTH INTO CANADA
BY MONDAY AND SOMEWHAT ZONAL FLOW ESTABLISHES ITSELF OVER THE
NORTHERN TIER OF THE CONUS. HOWEVER... THE MEDIUM RANGE GUIDANCE
SUGGESTS SOME TROUGHING DEVELOPING TO OUR WEST BY MIDWEEK WHICH
WILL BRING SOME MORE ACTIVE WEATHER BACK INTO THE AREA BY MIDWEEK
INTO THE LATTER HALF OF THE WEEK. ON THE WHOLE... THE WEATHER WILL
BE SOMEWHAT UNSETTLED THROUGH THE UPCOMING WEEK... BUT AT THE
CURRENT TIME THE ONLY SYSTEM OF ANY PARTICULAR SIGNIFICANCE MAY BE
THE MIDWEEK FEATURE... WHICH COULD HAVE SOME INSTABILITY WITH
WHICH TO WORK AS IT MOVES ACROSS THE AREA ON WEDNESDAY.
AS ALLUDED TO EARLIER... EXPECT TO SEE WIDESPREAD SHRA ACTIVITY
THIS MORNING AS SOME ISENTROPIC UPGLIDE WORKS TO SUSTAIN THE
ACTIVITY CURRENTLY MOVING IN FROM OUR SOUTH EVEN THOUGH THE UPPER
SUPPORT AND DPVA WILL BE FADING WITH TIME AS THE SHORTWAVE
CONTINUES TO SHEAR OUT. LOWEST CHANCES FOR MEASURABLE PCPN WILL BE
OVER THE NORTHEAST CWFA. THE SOUTHEAST CWFA COULD SEE SOME
THUNDER... BUT AT THIS POINT FORECAST 850-500MB DIFFERENTIAL
THETA-E VALUES FROM THE NAM AND GFS SUGGEST LEAVING THAT MENTION
OUT OF THE FORECAST. CURRENT TEMPERATURES ACROSS THE AREA... ALONG
WITH THE 00Z KMPX SOUNDING AND FORECAST SOUNDINGS FROM THE RUC...
SUGGEST IT WILL BE VERY DIFFICULT TO GET ANY SNOWFLAKES FROM THIS
ACTIVITY TODAY. NOT ONLY ARE TEMPERATURES IN THE BOTTOM THOUSAND
OR SO FEET QUITE WARM... BUT AN ELEVATED WARM LAYER IS STILL NOT
COMPLETELY VANQUISHED... AND THUS FAR THERE IS MINIMAL EVIDENCE
SUGGESTING THAT WILL OCCUR. SO... REMOVED ANY MENTION OF SNOW FROM
THE FORECAST FOR TODAY. SHOULD A SUFFICIENTLY HEAVY SHRA OCCUR IT
ISN/T OUT OF THE QUESTION THAT A FEW FLAKES COULD FIND THEIR WAY
TO THE GROUND... BUT ANY SUCH OCCURRENCE WOULD BE ISOLATED AND OF
NO IMPACT SINCE IT WOULD BE SHORT-LIVED AND NON-ACCUMULATING.
LINGERED SOME LOW CHANCE POPS INTO TONIGHT AS THE MID-LEVEL
BAROCLINIC ZONE AND DEEPER MOISTURE WASHES OUT OVER THE AREA. WE
SHOULD FIND OURSELVES SUFFICIENTLY DRY ON SUNDAY AS SOME MODEST
RIDGING SURFACE AND ALOFT BECOMES ESTABLISHED OVER THE AREA... SO
EXCLUDED POPS FROM THE SUNDAY FORECAST. HOWEVER... BY SUNDAY NIGHT
WE COULD SEE SOME LIGHT PCPN WORK ACROSS THE REGION AS THE UPPER
LOW CURRENTLY TO OUR WEST WORKS INTO SOUTHERN CANADA AND HELPS
DRAG A MID-LEVEL TROUGH THROUGH THE STATE ALONG WITH A WEAK
SURFACE TROUGH. THE BEST CHANCES FOR PCPN LOOK TO BE CLOSER TO THE
MAIN UPPER SYSTEM TO OUR NORTH AND CLOSER TO THE BETTER
INSTABILITY AND LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH AND
SOUTHEAST. HOWEVER... GIVEN SUFFICIENT DEEP LAYER MOISTURE AND
SOME WEAK FORCING... LOW POPS SEEM WARRANTED FOR MUCH OF THE AREA
SUNDAY NIGHT INTO MONDAY.
MADE MINIMAL CHANGES TO THE GOING FORECAST FROM MONDAY NIGHT
THROUGH FRIDAY... MEANING THERE CONTINUES TO BE A MENTION OF PCPN
EACH DAY. BY NO MEANS DOES THE ENTIRE PERIOD LOOK LIKE A
WASHOUT... BUT THERE IS SUFFICIENT SPREAD MODEL SOLUTIONS BOTH
WITH RESPECT TO TIMING AND AMPLITUDE OF FEATURES TO INCLUDE PCPN
CHANCES EACH DAY. AT THIS POINT... THE BEST CHANCE FOR WIDESPREAD
PCPN LOOKS TO BE TUESDAY NIGHT AND WEDNESDAY AS WE INITIALLY SEE
SOME HEALTHY RETURN FLOW AND WARM AIR ADVECTION... FOLLOWED BY THE
PASSAGE OF A SURFACE LOW AND ATTENDANT SHARP COLD FRONT THROUGH
THE REGION. AFTER THIS SYSTEM MOVES THROUGH... WE LOOK TO MAINTAIN
A BAROCLINIC ZONE NEARBY FOR THE NEXT FEW DAYS AS A FEW SUCCESSIVE
SHORTWAVES MIGRATE THROUGH ON FAIRLY QUICKLY WESTERLY MID-UPPER
LEVEL FLOW.
&&
.AVIATION.../18Z TAF ISSUANCE/
A DECREASING AREA OF -RA...WHICH IS BASICALLY BISECTING THE FA
FROM THE SE TO THE NW...WILL LIKELY BE THE MAIN PLAYER TO FINALLY
SATURATE THE LOWEST 1 KM THIS AFTN. ALTHOUGH MVFR CIGS HAVE BEEN
CONFINED TO AREAS SOUTH OF I-94...WITH IFR CIGS ALONG THE
MINNESOTA RIVER VALLEY AND SOUTHWARD THIS MORNING. E/SE WNDS AND THE
ADDED MOISTURE FROM RAINFALL THIS MORNING...WILL AID IN THE
DEVELOPMENT OF LOWER CIGS. ONLY CONCERN IS HOW FAR NE DOES THESE
LOWER CIGS MOVE THIS AFTN/EVENING...WITH THE POSSIBILITY OF FG/BR
DEVELOPING AFT MIDNIGHT.
WILL LIKE TO CONTINUE THE SAME TREND WITH SOME MODIFICATION OF
TIMING TO THE 18Z TAFS. CIGS WILL EVENTUALLY BECOME OR REMAIN MVFR
ACROSS ALL BUT RNH/EAU...BUT LOW CONFIDENCE AT THESE SITES
CONTINUE WITH THE DRY EASTERLY WNDS. ALL THE LIFT ASSOCIATED WITH
THE MORNING RAINFALL WILL END THIS AFTN...WITH ONLY DRIZZLE/BR/FG
PERSISTING THRU THE OVERNIGHT/EARLY SUNDAY. MAIN CONCERN AFT
MIDNIGHT IS FG WITH IFR/LIFR CIGS AT RWF...BUT CONTINUE THE SAME
TREND WITH ONLY IFR CIGS AND MVFR VSBYS. WNDS WILL REMAIN FROM THE
E/ESE THIS AFTN...BECOMING MORE SE SUNDAY MORNING...BUT UNDER 12 KTS.
MSP...MVFR CIGS ARND THE TERMINAL SITE...BUT NOT WIDESPREAD ENOUGH
TO BE PERSISTENT UNTIL AFT 21Z. THEREFORE...TEMPORARY CIGS OF 2.5K
SEEMS MORE APPROPRIATE. AFT 21Z...MVFR CIGS AND SOME BR IS LIKELY
WITH HIGH CONFIDENCE. DURING THE EVENING/OVERNIGHT PERIOD...CONFIDENCE
OF MVFR CIGS REMAINS HIGH...BUT THERE COULD BE A FEW BREAKS IN THE
OVERCAST IF DRIER AIR FROM THE EAST TAKES OVER. VFR CIGS SHOULD BE
DEVELOPING SUNDAY MORNING...WITH A MORE SE WND UNTIL 10 KTS AFT
14Z.
.OUTLOOK...
.SUN...VFR CONDS.
.MON-WED...PERIODS OF SHWRS/TSTMS. MVFR TO IFR CONDS POSSIBLE.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
644 AM CDT SAT APR 28 2012
.UPDATE...
UPDATED TO INCLUDE 12Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSES SHOW AN
AMPLIFIED AND VISUALLY CONVOLUTED PATTERN ACROSS THE CONTINENT AT
THE CURRENT TIME. A CUTOFF UPPER LOW CIRCULATING OVER THE NORTHERN
ROCKIES IS WORKING TO EJECT A SHORTWAVE NORTH INTO SOUTHERN
MINNESOTA... WHICH IS HELPING TO PRODUCE THE BAND OF SHRA ACROSS
THE SOUTHERN PART OF THE FORECAST AREA AT THE CURRENT TIME.
HOWEVER... THIS FEATURE IS RUNNING INTO THE UPPER RIDGE WHICH
EXTENDS FROM CENTRAL SASKATCHEWAN SOUTHEAST THROUGH WISCONSIN...
WHICH IS SHEARING IT OUT WITH TIME AND WORKING TO DIMINISH THE
PCPN AS IT WORKS NORTHWARD. A SECONDARY SURGE OF PCPN WITH THE
UPPER TROUGH TO OUR SOUTH... COINCIDENT WITH BETTER MID-LEVEL
INSTABILITY... IS IN IOWA AND IS ALSO WORKING NORTHWARD WITH TIME.
THE LATEST HRRR AND HIGH RESOLUTION WINDOW RUNS SEEM TO HAVE A
DECENT HANDLE ON ALL OF THIS ACTIVITY... AND SUGGEST IT SHOULD
CONTINUE TO WORK UP INTO THE FORECAST AREA THIS MORNING INTO EARLY
AFTERNOON... WITH ITS NORTHERN EDGE HAVING A TOUGH TIME MAKING IT
INTO THE NORTH CENTRAL AND NORTHEAST PORTION OF THE AREA GIVEN DRY
LOW LEVEL AIR BACK-FEEDING INTO THE REGION FROM THE SURFACE HIGH
POSITIONED TO OUR EAST. AS FAR AS THE LARGE SCALE PATTERN GOES...
OVERALL IT LOOKS TO DE-AMPLIFY AS WE HEAD INTO THE EARLY PART OF
NEXT WEEK... AS THE UPPER LOW TO OUR WEST SLIDES NORTH INTO CANADA
BY MONDAY AND SOMEWHAT ZONAL FLOW ESTABLISHES ITSELF OVER THE
NORTHERN TIER OF THE CONUS. HOWEVER... THE MEDIUM RANGE GUIDANCE
SUGGESTS SOME TROUGHING DEVELOPING TO OUR WEST BY MIDWEEK WHICH
WILL BRING SOME MORE ACTIVE WEATHER BACK INTO THE AREA BY MIDWEEK
INTO THE LATTER HALF OF THE WEEK. ON THE WHOLE... THE WEATHER WILL
BE SOMEWHAT UNSETTLED THROUGH THE UPCOMING WEEK... BUT AT THE
CURRENT TIME THE ONLY SYSTEM OF ANY PARTICULAR SIGNIFICANCE MAY BE
THE MIDWEEK FEATURE... WHICH COULD HAVE SOME INSTABILITY WITH
WHICH TO WORK AS IT MOVES ACROSS THE AREA ON WEDNESDAY.
AS ALLUDED TO EARLIER... EXPECT TO SEE WIDESPREAD SHRA ACTIVITY
THIS MORNING AS SOME ISENTROPIC UPGLIDE WORKS TO SUSTAIN THE
ACTIVITY CURRENTLY MOVING IN FROM OUR SOUTH EVEN THOUGH THE UPPER
SUPPORT AND DPVA WILL BE FADING WITH TIME AS THE SHORTWAVE
CONTINUES TO SHEAR OUT. LOWEST CHANCES FOR MEASURABLE PCPN WILL BE
OVER THE NORTHEAST CWFA. THE SOUTHEAST CWFA COULD SEE SOME
THUNDER... BUT AT THIS POINT FORECAST 850-500MB DIFFERENTIAL
THETA-E VALUES FROM THE NAM AND GFS SUGGEST LEAVING THAT MENTION
OUT OF THE FORECAST. CURRENT TEMPERATURES ACROSS THE AREA... ALONG
WITH THE 00Z KMPX SOUNDING AND FORECAST SOUNDINGS FROM THE RUC...
SUGGEST IT WILL BE VERY DIFFICULT TO GET ANY SNOWFLAKES FROM THIS
ACTIVITY TODAY. NOT ONLY ARE TEMPERATURES IN THE BOTTOM THOUSAND
OR SO FEET QUITE WARM... BUT AN ELEVATED WARM LAYER IS STILL NOT
COMPLETELY VANQUISHED... AND THUS FAR THERE IS MINIMAL EVIDENCE
SUGGESTING THAT WILL OCCUR. SO... REMOVED ANY MENTION OF SNOW FROM
THE FORECAST FOR TODAY. SHOULD A SUFFICIENTLY HEAVY SHRA OCCUR IT
ISN/T OUT OF THE QUESTION THAT A FEW FLAKES COULD FIND THEIR WAY
TO THE GROUND... BUT ANY SUCH OCCURRENCE WOULD BE ISOLATED AND OF
NO IMPACT SINCE IT WOULD BE SHORT-LIVED AND NON-ACCUMULATING.
LINGERED SOME LOW CHANCE POPS INTO TONIGHT AS THE MID-LEVEL
BAROCLINIC ZONE AND DEEPER MOISTURE WASHES OUT OVER THE AREA. WE
SHOULD FIND OURSELVES SUFFICIENTLY DRY ON SUNDAY AS SOME MODEST
RIDGING SURFACE AND ALOFT BECOMES ESTABLISHED OVER THE AREA... SO
EXCLUDED POPS FROM THE SUNDAY FORECAST. HOWEVER... BY SUNDAY NIGHT
WE COULD SEE SOME LIGHT PCPN WORK ACROSS THE REGION AS THE UPPER
LOW CURRENTLY TO OUR WEST WORKS INTO SOUTHERN CANADA AND HELPS
DRAG A MID-LEVEL TROUGH THROUGH THE STATE ALONG WITH A WEAK
SURFACE TROUGH. THE BEST CHANCES FOR PCPN LOOK TO BE CLOSER TO THE
MAIN UPPER SYSTEM TO OUR NORTH AND CLOSER TO THE BETTER
INSTABILITY AND LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH AND
SOUTHEAST. HOWEVER... GIVEN SUFFICIENT DEEP LAYER MOISTURE AND
SOME WEAK FORCING... LOW POPS SEEM WARRANTED FOR MUCH OF THE AREA
SUNDAY NIGHT INTO MONDAY.
MADE MINIMAL CHANGES TO THE GOING FORECAST FROM MONDAY NIGHT
THROUGH FRIDAY... MEANING THERE CONTINUES TO BE A MENTION OF PCPN
EACH DAY. BY NO MEANS DOES THE ENTIRE PERIOD LOOK LIKE A
WASHOUT... BUT THERE IS SUFFICIENT SPREAD MODEL SOLUTIONS BOTH
WITH RESPECT TO TIMING AND AMPLITUDE OF FEATURES TO INCLUDE PCPN
CHANCES EACH DAY. AT THIS POINT... THE BEST CHANCE FOR WIDESPREAD
PCPN LOOKS TO BE TUESDAY NIGHT AND WEDNESDAY AS WE INITIALLY SEE
SOME HEALTHY RETURN FLOW AND WARM AIR ADVECTION... FOLLOWED BY THE
PASSAGE OF A SURFACE LOW AND ATTENDANT SHARP COLD FRONT THROUGH
THE REGION. AFTER THIS SYSTEM MOVES THROUGH... WE LOOK TO MAINTAIN
A BAROCLINIC ZONE NEARBY FOR THE NEXT FEW DAYS AS A FEW SUCCESSIVE
SHORTWAVES MIGRATE THROUGH ON FAIRLY QUICKLY WESTERLY MID-UPPER
LEVEL FLOW.
&&
.AVIATION.../12Z TAF ISSUANCE/
AREA OF LOW PRES CENTERED OVER SW IA/NW MO WILL CONTINUE TO SHIFT
E THROUGH THE DAY TDA. DEEPER MOISTURE WITH THIS SYSTEM WILL MAKE
FOR BANDS OF LGT/MOD RAIN TO SPREAD N INTO SRN AND CENTRAL MN AND
SW WI. MAINLY THE MN TAF SITES...PARTICULARLY KRWF...WILL BE MOST
SUSCEPTIBLE TO DROPPING INTO MVFR DUE TO DEGRADED VSBY WITH
HEAVIER RAIN. AS THE RAIN GRADUALLY ENDS THIS AFTN...LOWER CIGS
WILL SETTLE IN. THE STRONGER E-SE WINDS THROUGH THE AFTN WILL
PREVENT CIGS FROM DROPPING ANY LOWER THAN MVFR. HOWEVER...LATER
THIS EVE INTO THE OVERNIGHT HOURS...AS WINDS DROP TO AOB 10 KT...
CIGS LOOK LIKELY TO DROP INTO IFR RANGE FOR SEVERAL HOURS BEFORE
IMPROVING AFTER DAYBREAK SUNDAY.
MSP...VFR TO START WITH SPRINKLES/-SHRA OVER THE AREA BUT HEAVIER
AND STEADIER RAINS WILL GRADUALLY MOVE OVER THE FIELD BY LATE
MORNING...DROPPING VSBY INTO MVFR RANGE FOR AT LEAST A COUPLE OF
HOURS. CIGS DURING THE RAIN WILL REMAIN AT VFR...ESPECIALLY WITH
THE STRONGER SE WINDS FOR MUCH OF THE DAY. ONCE THE RAIN ENDS...
LOWER CEILINGS WILL SETTLE IN...INCLUDING CEILINGS THAT HIT THE
1800 FT THRESHOLD BY THIS EVENING. AS WINDS DROP OFF...WILL LOOK
FOR CEILINGS TO CONTINUE TO LOWER AND AM EXPECTING CIGS TO HIT IFR
RANGE DURING THE OVERNIGHT HOURS TONIGHT. CONDITIONS SHOULD
IMPROVE AFTER DAYBREAK TMRW.
OUTLOOK...
SUN...VFR CONDITIONS WITH MIDLVL CEILINGS UNDER HIGH PRESSURE.
MON-WED...SEVERAL FRONTAL SYSTEMS TO PUSH THROUGH THE REGION...
RESULTING IN PERIODS OF SHWRS/TSTMS. MVFR TO IFR CONDS POSSIBLE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
242 AM CDT SAT APR 28 2012
.DISCUSSION...
CURRENT WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSES SHOW AN
AMPLIFIED AND VISUALLY CONVOLUTED PATTERN ACROSS THE CONTINENT AT
THE CURRENT TIME. A CUTOFF UPPER LOW CIRCULATING OVER THE NORTHERN
ROCKIES IS WORKING TO EJECT A SHORTWAVE NORTH INTO SOUTHERN
MINNESOTA... WHICH IS HELPING TO PRODUCE THE BAND OF SHRA ACROSS
THE SOUTHERN PART OF THE FORECAST AREA AT THE CURRENT TIME.
HOWEVER... THIS FEATURE IS RUNNING INTO THE UPPER RIDGE WHICH
EXTENDS FROM CENTRAL SASKATCHEWAN SOUTHEAST THROUGH WISCONSIN...
WHICH IS SHEARING IT OUT WITH TIME AND WORKING TO DIMINISH THE
PCPN AS IT WORKS NORTHWARD. A SECONDARY SURGE OF PCPN WITH THE
UPPER TROUGH TO OUR SOUTH... COINCIDENT WITH BETTER MID-LEVEL
INSTABILITY... IS IN IOWA AND IS ALSO WORKING NORTHWARD WITH TIME.
THE LATEST HRRR AND HIGH RESOLUTION WINDOW RUNS SEEM TO HAVE A
DECENT HANDLE ON ALL OF THIS ACTIVITY... AND SUGGEST IT SHOULD
CONTINUE TO WORK UP INTO THE FORECAST AREA THIS MORNING INTO EARLY
AFTERNOON... WITH ITS NORTHERN EDGE HAVING A TOUGH TIME MAKING IT
INTO THE NORTH CENTRAL AND NORTHEAST PORTION OF THE AREA GIVEN DRY
LOW LEVEL AIR BACK-FEEDING INTO THE REGION FROM THE SURFACE HIGH
POSITIONED TO OUR EAST. AS FAR AS THE LARGE SCALE PATTERN GOES...
OVERALL IT LOOKS TO DE-AMPLIFY AS WE HEAD INTO THE EARLY PART OF
NEXT WEEK... AS THE UPPER LOW TO OUR WEST SLIDES NORTH INTO CANADA
BY MONDAY AND SOMEWHAT ZONAL FLOW ESTABLISHES ITSELF OVER THE
NORTHERN TIER OF THE CONUS. HOWEVER... THE MEDIUM RANGE GUIDANCE
SUGGESTS SOME TROUGHING DEVELOPING TO OUR WEST BY MIDWEEK WHICH
WILL BRING SOME MORE ACTIVE WEATHER BACK INTO THE AREA BY MIDWEEK
INTO THE LATTER HALF OF THE WEEK. ON THE WHOLE... THE WEATHER WILL
BE SOMEWHAT UNSETTLED THROUGH THE UPCOMING WEEK... BUT AT THE
CURRENT TIME THE ONLY SYSTEM OF ANY PARTICULAR SIGNIFICANCE MAY BE
THE MIDWEEK FEATURE... WHICH COULD HAVE SOME INSTABILITY WITH
WHICH TO WORK AS IT MOVES ACROSS THE AREA ON WEDNESDAY.
AS ELUDED TO EARLIER... EXPECT TO SEE WIDESPREAD SHRA ACTIVITY
THIS MORNING AS SOME ISENTROPIC UPGLIDE WORKS TO SUSTAIN
THE ACTIVITY CURRENTLY MOVING IN FROM OUR SOUTH EVEN THOUGH THE
UPPER SUPPORT AND DPVA WILL BE FADING WITH TIME AS THE SHORTWAVE
CONTINUES TO SHEAR OUT. LOWEST CHANCES FOR MEASURABLE PCPN WILL
BE OVER THE NORTHEAST CWFA. THE SOUTHEAST CWFA COULD SEE SOME
THUNDER... BUT AT THIS POINT FORECAST 850-500MB DIFFERENTIAL
THETA-E VALUES FROM THE NAM AND GFS SUGGEST LEAVING THAT MENTION
OUT OF THE FORECAST. CURRENT TEMPERATURES ACROSS THE AREA... ALONG
WITH THE 00Z KMPX SOUNDING AND FORECAST SOUNDINGS FROM THE RUC...
SUGGEST IT WILL BE VERY DIFFICULT TO GET ANY SNOWFLAKES FROM THIS
ACTIVITY TODAY. NOT ONLY ARE TEMPERATURES IN THE BOTTOM THOUSAND
OR SO FEET QUITE WARM... BUT AN ELEVATED WARM LAYER IS STILL NOT
COMPLETELY VANQUISHED... AND THUS FAR THERE IS MINIMAL EVIDENCE
SUGGESTING THAT WILL OCCUR. SO... REMOVED ANY MENTION OF SNOW FROM
THE FORECAST FOR TODAY. SHOULD A SUFFICIENTLY HEAVY SHRA OCCUR IT
ISN/T OUT OF THE QUESTION THAT A FEW FLAKES COULD FIND THEIR WAY
TO THE GROUND... BUT ANY SUCH OCCURRENCE WOULD BE ISOLATED AND OF
NO IMPACT SINCE IT WOULD BE SHORT-LIVED AND NON-ACCUMULATING.
LINGERED SOME LOW CHANCE POPS INTO TONIGHT AS THE MID-LEVEL
BAROCLINIC ZONE AND DEEPER MOISTURE WASHES OUT OVER THE AREA. WE
SHOULD FIND OURSELVES SUFFICIENTLY DRY ON SUNDAY AS SOME MODEST
RIDGING SURFACE AND ALOFT BECOMES ESTABLISHED OVER THE AREA... SO
EXCLUDED POPS FROM THE SUNDAY FORECAST. HOWEVER... BY SUNDAY NIGHT
WE COULD SEE SOME LIGHT PCPN WORK ACROSS THE REGION AS THE UPPER
LOW CURRENTLY TO OUR WEST WORKS INTO SOUTHERN CANADA AND HELPS
DRAG A MID-LEVEL TROUGH THROUGH THE STATE ALONG WITH A WEAK
SURFACE TROUGH. THE BEST CHANCES FOR PCPN LOOK TO BE CLOSER TO THE
MAIN UPPER SYSTEM TO OUR NORTH AND CLOSER TO THE BETTER
INSTABILITY AND LOW LEVEL BAROCLINIC ZONE TO OUR SOUTH AND
SOUTHEAST. HOWEVER... GIVEN SUFFICIENT DEEP LAYER MOISTURE AND
SOME WEAK FORCING... LOW POPS SEEM WARRANTED FOR MUCH OF THE AREA
SUNDAY NIGHT INTO MONDAY.
MADE MINIMAL CHANGES TO THE GOING FORECAST FROM MONDAY NIGHT
THROUGH FRIDAY... MEANING THERE CONTINUES TO BE A MENTION OF PCPN
EACH DAY. BY NO MEANS DOES THE ENTIRE PERIOD LOOK LIKE A
WASHOUT... BUT THERE IS SUFFICIENT SPREAD MODEL SOLUTIONS BOTH
WITH RESPECT TO TIMING AND AMPLITUDE OF FEATURES TO INCLUDE PCPN
CHANCES EACH DAY. AT THIS POINT... THE BEST CHANCE FOR WIDESPREAD
PCPN LOOKS TO BE TUESDAY NIGHT AND WEDNESDAY AS WE INITIALLY SEE
SOME HEALTHY RETURN FLOW AND WARM AIR ADVECTION... FOLLOWED BY THE
PASSAGE OF A SURFACE LOW AND ATTENDANT SHARP COLD FRONT THROUGH
THE REGION. AFTER THIS SYSTEM MOVES THROUGH... WE LOOK TO MAINTAIN
A BAROCLINIC ZONE NEARBY FOR THE NEXT FEW DAYS AS A FEW SUCCESSIVE
SHORTWAVES MIGRATE THROUGH ON FAIRLY QUICKLY WESTERLY MID-UPPER
LEVEL FLOW.
&&
.AVIATION.../06Z TAF ISSUANCE/
/ISSUED 1155 PM CDT FRI APR 27 2012/
DRY AIR IN THE LOWER LEVELS KEEPING MOST OF THE RAIN OVER
SOUTHWEST MINNESOTA AT THIS TIME...WITH JUST A VERY SLOW NORTHEAST
TREND OVERNIGHT PROBABLY REACHING KMSP/KSTC/KAXN BY AROUND 09Z-
10Z. CONSEQUENTLY...CIGS AND VSBYS REMAINING VFR MOST AREAS
OVERNIGHT WITH THE BETTER CHANCE OF MVFR AT KRWF. EXPECT THE RAIN
AND AT LEAST LOW LEVEL VFR TO EXPAND OVER THE MN PORTION OF THE
AREA DURING EARLY SATURDAY MORNING...AND THEN MVFR OVER MN SITES
LATE MORNING OR EARLY AFTERNOON. STILL A SLIGHT CHANCE OF A RAIN
AND SNOW MIX NOT ENOUGH CONFIDENCE TO MENTION IN TAFS. THE FORCING
FOR THE PRECIP GRADUALLY WEAKENS AND MOVES OFF TO THE NORTHEAST BY
EVENING BUT MVFR CIGS TO PERSIST OVER MN SITES WITH A SLIGHT
CHANCE OF IFR OVER KAXN. STILL BRISK EAST TO SOUTHEAST WINDS
OVERNIGHT INTO SATURDAY BUT DECREASING SATURDAY EVENING WITH THE
LOW PRES FILLING.
KMSP...VFR CIGS PERSISTING INTO THE OVERNIGHT HOURS BUT LOWERING TO
MVFR FROM 16-17Z WITH MORE PERSISTENT RAIN. THINKING THAT CIGS WILL
REMAIN ABOVE 017. RAIN DECREASING BY EVENING BUT CIGS REMAINING MVFR
WITH POSSIBILITY OF LEVELS DROPPING BLO 015 AFTER 06Z. GUSTY EAST
WINDS TO 24 KNOTS OVERNIGHT INTO SATURDAY BUT GUSTS ENDING AFTER
00Z.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
/JPR
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1051 PM CDT SUN APR 29 2012
...MESOSCALE CONVECTIVE DISCUSSION...
.UPDATE...
/ISSUED 1051 PM CDT SUN APR 29 2012/
POTENTIALLY DANGEROUS HEAVY RAINFALL AND FLASH FLOOD SITUATION
UNFOLDING ACROSS PORTIONS OF THE OUTLOOK AREA.
WAVY...STATIONARY SURFACE BOUNDARY EXTENDS FROM NEAR ROLLA TO JUST
NORTH OF NEVADA AND FORT SCOTT. OVER THE PAST FEW HOURS...LARGE
SCALE LIFT HAS INCREASE AND CONVECTION ALONG AND SOUTH OF THIS
BOUNDARY HAS BLOSSOMED. COMBINATION OF MULTICELL CLUSTERS AND A
FEW EMBEDDED SUPERCELLS HAVE BEEN OBSERVED TO THIS POINT.
SUPERCELL STRUCTURES AND ANY BOWING SEGMENTS THAT CAN DEVELOP WILL
POSE OUR MAIN SEVERE WEATHER THREAT...WITH MARGINALLY SEVERE HAIL
AND LOCALIZED DAMAGING WIND GUSTS THE PRIMARY CONCERN. THE LOW
LEVEL JET HAS RAMPED UP...RESULTING IN A LIMITED TORNADO RISK...
MAINLY ACROSS EXTREME SOUTHEAST KANSAS AND ADJACENT COUNTIES IN
MISSOURI FOR THE NEXT COUPLE OF HOURS. REALLY CANNOT RULE OUT A
FEW SEVERE CELLS FROM TIME TO TIME AT ANY POINT FOR THE REST OF
TONIGHT. AS THE LOW LEVEL JET VEERS THE CURRENT AXIS OF CONVECTION
WILL TEND TO SHIFT TO THE SOUTH WITH NEW CELL DEVELOPMENT POSSIBLE
ON THE SOUTHEASTERN FLANK CLOSER TO THE I-44 CORRIDOR. MARGINALLY
SEVERE HAIL/LOCALIZED DAMAGING WIND WILL REMAIN THE PRIMARY RISKS.
OF LARGER CONCERN WILL BE HEAVY RAINFALL PRODUCTION OVERNIGHT.
AT THE SURFACE...DEWPOINT POOLING IS BEING OBSERVED. MEANWHILE A 30
TO 40 KT LOW LEVEL JET IS PROVIDING A STRONG INFLUX OF LOW LEVEL
MOISTURE. PRECIPITABLE WATER VALUES AROUND 1.8 INCHES HAVE BEEN
IDENTIFIED BY RUC INITIALIZATIONS ALONG AND SOUTH OF THE SURFACE
BOUNDARY...WHICH IS IN THE 99TH PERCENTILE FOR THIS TIME OF YEAR.
IN ADDITION...TRADITIONAL STORM MOTION VECTORS ARE RATHER LIGHT
NEAR THE BOUNDARY AND RECENT RUC PROGS DO NOT CHANGE THIS FOR THE
NEXT 3 TO 6 HOURS. AS A RESULT...THE CURRENT ORIENTATION OF
CONVECTION IS NOT EXPECTED TO CHANGE VERY MUCH OVER THE NEXT 3 TO
6 HOURS.
THUNDERSTORM TRAINING AND EFFICIENT HEAVY RAINFALL PRODUCTION WILL
RESULT IN A SIGNIFICANT RISK OF FLASH FLOODING ACROSS PORTIONS OF
CRAWFORD AND BOURBON COUNTIES IN KANSAS AS WELL AS BARTON...
VERNON...CEDAR AND ST. CLAIR COUNTIES IN MISSOURI OVER THE NEXT
2 TO 4 HOURS. WIDESPREAD RAINFALL OF TWO TO FIVE INCHES IS
EXPECTED...WITH LOCALLY HIGHER AMOUNTS UPWARD OF SEVEN INCHES
POSSIBLE. THE RISK FOR HEAVY RAIN AND FLASH FLOODING IN ADJACENT
COUNTIES WILL HAVE TO BE MONITORED VERY CLOSELY. AS MENTIONED
ABOVE...A VEERING LOW LEVEL JET WILL ALLOW THE AXIS OF CONVECTION
TO SHIFT TO THE SOUTH AND SOUTHEAST AFTER (ROUGHLY) 09Z...SO
TRAINING SHOULD LESSEN WITH TIME AND RAINFALL WILL BEGIN TO AFFECT
AREAS THAT HAVE NOT SEEN MUCH IN THE WAY OF RAIN THE PAST FEW DAYS.
GAGAN
&&
.DISCUSSION...
/ISSUED 335 PM CDT SUN APR 29 2012/
THE ACTIVE WEATHER WILL CONTINUE INTO MONDAY AND AT LEAST PART OF
TUESDAY AS THE EXISTING BOUNDARY REMAINS STALLED ACROSS THE AREA
UNDERNEATH A BROAD SOUTHWESTERLY FLOW ALOFT.
PINPOINTING THE HIGHEST CHANCES OF SHOWERS AND THUNDERSTORMS WILL
BE CHALLENGING BUT THE ACTIVITY WILL LIKELY TEND FOCUS ALONG AND
NORTH OF THE BOUNDARY AS IT INTERACTS WITH THE NIGHT TIME LOW
LEVEL JET.
THE RISK OF SEVERE WEATHER APPEARS TO BE LIMITED AT BEST MONDAY
AND TUESDAY AND WILL BE DEPENDENT ON THE EXTENT OF DESTABILIZATION
THAT CAN OCCUR. MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL
LEAD TO AN INCREASING RISK OF FLASH FLOODING ESPECIALLY FROM
SOUTHEAST KANSAS INTO SOUTHWEST AND CENTRAL MISSOURI ALONG AND
NORTH OF THE BOUNDARY WHERE A FLASH FLOOD WATCH HAS BEEN ISSUED.
WARMER TEMPERATURES AND A DRYING TREND IS IN STORE FROM MID TO
LATE WEEK AS UPPER LEVEL RIDGING GRADUALLY DEVELOPS.
FOSTER
&&
.AVIATION...
SHOWERS...THUNDERSTORMS...AND ASSOCIATED LOWERED CEILINGS WILL
CONTINUE TO BE THE PRIMARY IMPACT TO AVIATION OVER THE NEXT 24
HOURS. A FRONTAL BOUNDARY THAT HAS LINGERED OVER THE REGION FOR
THE PAST SEVERAL DAYS WILL SLOWLY MOVE TO THE EAST IN RESPONSE TO
AN APPROACHING UPPER LEVEL DISTURBANCE. PRECIPITATION CHANCES
WILL GRADUALLY INCREASE OVERNIGHT AND INTO TOMORROW WITH CHANCES
FOR MVFR...POSSIBLY SOME IFR CONDITIONS...EARLY TOMORROW. THE
FORECAST CONFIDENCE FOR TIMING OF THUNDERSTORMS AND LOWERED
CEILINGS IS QUITE LOW IN THIS TYPE OF SLOW MOVING FRONTAL
PATTERN.
KARDELL
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH UNTIL 10 AM CDT MONDAY FOR MOZ055>058-066>070-
077>081-088>090-093-094-101-102.
KS...FLASH FLOOD WATCH UNTIL 10 AM CDT MONDAY FOR KSZ073-097-101.
&&
$$
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1203 AM CDT SAT APR 28 2012
.UPDATE...
ISSUED AT 922 PM CDT FRI APR 27 2012
MADE ADJUSTMENTS TO RAIN CHANCES AND TEMPERATURES THE REST OF THE
NIGHT INTO SATURDAY MORNING BASED ON CURRENT TRENDS. OVERALL AREAL
COVERAGE OF STORMS OVER EASTERN KANSAS AND WESTERN MISSOURI HAS
DECREASED THE LAST TWO HOURS. ONE EXCEPTION IS AN ISOLATED STORM
THAT RECENTLY DEVELOPED AND HAS BECOME SEVERE BETWEEN MKC AND JLN.
RUNS OF THE HRRR REFLECTIVITY OUTPUT HAS SHOWN CORRECTLY THE
OVERALL LACK OF PRECIPITATION THIS EVENING...AND SHOWS THAT STORMS
DEVELOPING OVER WESTERN MO WILL MOVE NORTHEAST WITH TIME. RUC RUNS
CONTINUE TO SHOW A MARKED INCREASE IN 925-850MB MOISTURE CONVERGENCE
OVER THE NORTHEASTERN HALF OF THE CWA BY 06Z ON THE NOSE OF A BROAD
45KT LOW LEVEL JET. HAVE LOWERED POPS A BIT OVER THE SOUTHERN PART
OF THE CWA AND MAINTAINED LIKELY POPS TO THE NORTH OF I-70 BETWEEN
05-09Z BEFORE THE LOW LEVEL MOISTURE CONVERGENCE LIFTS NORTHEASTWARD.
CONSEQUENTLY ONLY HAVE SLIGHT CHANCES LATE TONIGHT INTO EARLY SATURDAY
OVER THE WHOLE CWA BEFORE THE POTENTIAL FOR SCATTERED THUNDERSTORMS
INCREASES AHEAD OF THE SURFACE LOW AND ATTENDANT COLD FRONT FROM
14Z ONWARD.
TEMPERATURES WILL LIKELY REMAIN STEADY OR SLOWLY RISE OVER THE SOUTHERN
CWA LATER TONIGHT WHEN WARM FRONT LIFTS NORTH INTO THE AREA.
BRITT
&&
.SHORT TERM...
ISSUED AT 319 PM CDT FRI APR 27 2012
(TONIGHT)
DEALING WITH AREA OF SHOWERS AND THUNDERSTORMS THAT DEVELOPED OVER
WESTERN/SOUTHWESTERN MO EARLIER THIS AFTERNOON AND IS TRACKING TO THE EAST
ACROSS FORECAST AREA AS OF 20Z. IT IS MOVING FAIRLY RAPIDLY AND SHOULD
BE EXITING AFTER 00Z. SO HAVE HIGHEST POPS OVER EASTERN PORTIONS
OF FORECAST AREA THIS EVENING. SOME CONCERN ABOUT ADDITIONAL DEVELOPMENT
AS SURFACE LOW TRACKS ACROSS AREA TONIGHT...SO KEPT HIGHEST POPS
NORTH OF SURFACE LOW TRACK...MAINLY OVER NORTHERN MO...INTO WEST
CENTRAL IL...BEFORE TAPERING OFF TOWARDS DAYBREAK. COULD SEE SOME
BRIEF HEAVY RAINFALL AND SMALL HAIL WITH SOME OF THE STRONGER STORMS.
OTHERWISE...DUE TO CLOUD COVER AND RAINFALL...TEMPS HAVE STRUGGLED
TO RISE MUCH TODAY...SO AS PCPN ENDS...COULD SEE TEMPS ACTUALLY
RISE A BIT BEFORE FALLING OFF. IT WILL BE CHILLY...WITH LOWS TONIGHT
IN THE UPPER 40S FAR NORTH TO THE UPPER 50S FAR SOUTH.
BYRD
&&
.LONG TERM...
ISSUED AT 319 PM CDT FRI APR 27 2012
(SATURDAY THROUGH FRIDAY)
MODELS CONTINUE TO HAVE DIFFERENT SOLUTIONS ON HOW TO HANDLE FRONTAL
BOUNDARY...WITH NAM HAVING BOUNDARY SINK SOUTH OF FORECAST AREA
DURING THE DAY ON SATURDAY...STALLING OUT JUST SOUTH OF FORECAST
AREA SATURDAY NIGHT AND SUNDAY. WHILE GFS/ECMWF HAS IT STALL OUT A
BIT FURTHER NORTH IN SOUTHERN PORTIONS OF FORECAST AREA. WILL LEAN
MORE TOWARDS GFS/ECMWF SOLUTION WITH BEST POPS ALONG AND SOUTH OF
I-70 THROUGH SUNDAY. THEN SUNDAY NIGHT AND MONDAY BETTER RAIN
CHANCES SHIFT TO THE NORTH AS NEXT IN A SERIES OF SHORTWAVES MOVES
ALONG FRONTAL BOUNDARY.
AS FOR TEMPS THROUGH THE PERIOD...SATURDAY WILL STILL BE RATHER
MILD...IN THE MID 60S FAR NORTH TO THE UPPER 70S SOUTH. THEN COOLER
AIR TO MAKE ITS WAY IN FOR THE LAST HALF OF THE WEEKEND BEFORE
MODERATING A BIT BY MONDAY. HIGHS ON SUNDAY WILL ONLY BE AROUND 60
FAR NORTH TO NEAR 70 FAR SOUTH...WARMING UP INTO THE UPPER 60S TO
MID 70S.
BEYOND THAT...WE REMAIN IN ACTIVE PATTERN WITH CHANCES OF SHOWERS
AND THUNDERSTORMS OFF AND ON THROUGH THE REST OF THE FORECAST
PERIOD. TEMPS TO CONTINUE MODERATING NEXT WEEK WITH HIGHS BACK IN
THE MID TO UPPER 70S BY TUESDAY...THEN WARMING UP INTO THE UPPER 70S
TO MID 80S THROUGH THE LAST HALF OF THE WORK WEEK.
BYRD
&&
.AVIATION...
ISSUED AT 1145 PM CDT FRI APR 27 2012
LOW PRESSURE OVER KANSAS IS MOVING EASTWARD TOWARD MISSOURI. A
BAND OF SHOWERS AND A FEW THUNDERSTORMS IS MOVING THROUGH
NORTHEAST MISSOURI AND THERE AREA ISOLATED SHOWERS AND STORMS OUT
AHEAD OF A WARM FRONT WHICH BE LIFTING INTO THE BI-STATE REGION
FROM SOUTHWEST MISSOURI. THERE APPEARS TO BE A SMALL WINDOW OF
OPPORTUNITY FOR ADDITIONAL THUNDERSTORM DEVELOPMENT AS MOIST AND
UNSTABLE AIR LIFTS OVER THE REGION BEFORE MORE STABLE AIR ALOFT
CAPS IT. WILL THEREFORE CONTINUE VCTS IN THE TERMINAL FORECASTS
ALONG THE I-70 CORRDIDOR. DO NOT SEE MUCH ADDITIONAL DEVELOPMENT
FOR THE QUINCY AREA OUTSIDE OF THE BAND MOVING THROUGH AT THIS
TIME. MVFR FLIGHT CONDITIONS WILL PREVAIL ACROSS PORTIONS OF THE
AREA AHEAD OF THE FRONT FOR A FEW HOURS. OTHERWISE...EXPCECT VFR
CONDTIONS TO PREVAIL. LOW LEVEL WIND SHEAR WILL BE A PROBLEM AS
THE STORM SYSTEM ALOFT MOVES ACROSS THE AREA AHEAD OF THE SURFACE
SYSTEM.
SPECIFICS FOR KSTL...
LOW PRESSURE OVER KANSAS IS MOVING EASTWARD TOWARD MISSOURI. THERE
APPEARS TO BE A SMALL WINDOW OF OPPORTUNITY FOR ADDITIONAL
THUNDERSTORM DEVELOPMENT AS MOIST AND UNSTABLE AIR LIFTS OVER THE
REGION BEFORE MORE STABLE AIR ALOFT CAPS IT. WILL THEREFORE
CONTINUE VCTS IN THE TERMINAL FORECAST FOR A FEW HOURS.
OTHERWISE...EXPCECT MVFR CONDTIONS TO PREVAIL FOR MUCH OF THE REST
OF THE NIGHT NORTH OF THE WARM FRONT. LOW LEVEL WIND SHEAR WILL BE A
PROBLEM AS THE STORM SYSTEM ALOFT MOVES ACROSS THE AREA AHEAD OF
THE SURFACE SYSTEM. COULD SEE THUNDERSTORMS AGAIN SATURDAY
AFTERNOON...BUT HAVE LEFT OUT FOR NOW. WILL LET SUBSEQUENT SHIFTS
TRY TO NAIL DOWN TIMING AND COVERAGE OF POTENTIAL THUNDERSTORMS.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1034 PM CDT SUN APR 29 2012
.AVIATION...
IFR CEILINGS AND/OR VISIBILITIES FORECAST AT KLBF BY 09Z COULD SET
IN SOONER. CURRENT 6SM BR SHOULD FALL TO BELOW 5SM BY 05Z WITH IFR
CEILINGS AS EARLY AS 07Z BASED ON RUC MODEL. LIFR CEILINGS ARE
POSSIBLE AND WILL NEED TO MONITOR. EXPECT VFR CONDITIONS AT
KVTN..ALTHOUGH STRATUS AND FOG COULD EXTEND AS CLOSE AS KANW.
&&
.PREV DISCUSSION... /ISSUED 908 PM CDT SUN APR 29 2012/
UPDATE...
UPDATED TO INCLUDE AREAS OF FOG AND STRATUS AFTER MIDNIGHT UNTIL
MID MORNING MONDAY. MOISTURE CONTINUES TO ADVECT INTO SOUTHWEST
AND CENTRAL NEBRASKA. STILL ISOLATED SHOWERS POSSIBLE OVERNIGHT IN
SOUTHWEST NEBRASKA. A NARROW LINE OF SHOWERS AND A FEW
THUNDERSTORMS CONTINUES ACROSS SOUTHEAST CHERRY COUNTY...WHICH
SHOULD DISSIPATE BY MIDNIGHT IN THE NORTH CENTRAL.
ROBERG
PREV DISCUSSION... /ISSUED 330 PM CDT SUN APR 29 2012/
SYNOPSIS...
AT 19Z...WATER VAPOR IMAGERY SHOWED A PLUME OF MOISTURE COMING
AROUND THE BASE OF A TROUGH FROM THE FOUR CORNERS REGION IN THE
SOUTHWEST AND INTO CENTRAL AND WESTERN NEBRASKA WHERE RADAR
INDICATED SOME LIGHT SHOWERS. ALSO...THE SMALL CYCLONE OVER THE
NORTHERN PLAINS HAD MOVED INTO SOUTHWEST MANITOBA. THE VISIBLE
IMAGERY INDICATED CLOUDS TAKING ON A MORE CUMULIFORM APPEARANCE...
SO THE LOWER LEVELS ARE DESTABILIZING. ANALYSIS OF THE 20Z SURFACE
DATA SHOWED A QUASI-STATIONARY FRONT ACROSS OKLAHOMA AND TEXAS INTO
NEW MEXICO. LOW PRESSURE WAS CENTERED ALONG THE CANADIAN BORDER AND
NORTH DAKOTA WITH A TROUGH THROUGH THE WESTERN DAKOTAS AND ACROSS
EXTREME EASTERN WYOMING AND EASTERN COLORADO.
DISCUSSION...
BY EARLY MONDAY...THE CYCLONE MOVES OUT OF THE NORTHERN PLAINS
AND THE FLOW ACROSS THE LOWER FORTY-EIGHT STATES BECOMES MORE
WESTERLY. THIS USHERS IN A MORE ACTIVE PERIOD IN WHICH UPPER WAVES
AND FRONTS MOVE THROUGH EVERY 24-36 HOURS. THERE IS DECENT AGREEMENT
AMONG THE SIMULATIONS THAT THE ACTIVE PATTERN WILL CONTINUE THROUGH
MOST OF THE FORECAST. HOWEVER...AFTER TUESDAY...THERE ARE
SIGNIFICANT DIFFERENCES WITH THE TIMING AND THE IMPACT OF EACH
SYSTEM.
SHORT RANGE...TONIGHT THROUGH TUESDAY NIGHT.
THE LIFT CURRENTLY ASSOCIATED WITH THE LIGHT SHOWERS IN WESTERN
NEBRASKA IS EXPECTED TO CUT OFF THIS EVENING. THEN...THERE WILL BE A
SHORT BREAK IN THE PRECIPITATION TONIGHT AND MONDAY MORNING. RETURN
FLOW IN THE 300-305K LAYER GENERATES SOME UPGLIDE AND MODERATE
MOISTURE TRANSPORT OVER NORTH CENTRAL THROUGH SOUTHWEST NEBRASKA
MONDAY AFTERNOON. WITH LIFTED INDICES OF ZERO TO -3C IN CENTRAL AND
SOUTHWEST NEBRASKA...AT LEAST ISOLATED THUNDERSTORMS CAN BE
EXPECTED.
ON TUESDAY...THE ACTIVITY IS LIKELY TO SHIFT TO CENTRAL AND
EASTERN NEBRASKA. THE GFS CONVECTIVE PARAMETERS INDICATE
1500-2500J/KG SURFACE BASED CONVECTIVE POTENTIAL IN NORTH CENTRAL
THROUGH SOUTH CENTRAL NEBRASKA...AND THE NAM SHOWS AS HIGH AS
4300J/KG. THE DEEP (0-6KM) BULK SHEAR IS FORECAST TO BE 35-45KT
WHICH MAY BE ENOUGH TO OFFSET THE UPDRAFT AND DOWNDRAFTS.
OVERALL...IT APPEARS THAT SEVERE STORMS ARE POSSIBLE BUT THE
PARAMETERS ARE MARGINAL. WITH UP TO AN INCH OF PRECIPITABLE
WATER...THERE IS POTENTIAL FOR VERY HEAVY RAIN.
MEDIUM RANGE/EXTENDED...WEDNESDAY THROUGH SUNDAY.
AS THE PROGRESSIVE UPPER AIR PATTERN CONTINUES AND A SURFACE
FRONT OSCILLATES NORTH AND SOUTH ACROSS THE CENTRAL PLAINS...AT
LEAST SLIGHT CHANCES OF RAIN AND THUNDERSTORMS WILL CONTINUE EACH
DAY WITH THE HIGHEST CHANCES IN CENTRAL AND SOUTHERN NEBRASKA.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...WFO LBF
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS HASTINGS NE
622 PM CDT SUN APR 29 2012
.AVIATION...00Z TAF. STRATUS HAS MOVED JUST EAST OF THE TERMINAL
AND EXPECT A COUPLE OF HOURS OF SCATTERED LOW CLOUDS UNTIL STRATUS
ADVECTS BACK TO THE WEST THIS EVENING...MAINLY AFTER DARK. STRATUS
LOOKS TO HOLD THROUGH THE NIGHT AND SOME REDUCED VSBYS IN FOG ARE
POSSIBLE IN PRESENCE OF LLVL MOISTURE AND EASTERLY LLVL FLOW. HAVE
MAINTAINED THE LIFR VSBY POTENTIAL LATER TONIGHT INTO MONDAY
MORNING. SOME QUESTION ON WHEN/IF CLOUDS WILL BREAK MONDAY BUT DID
RAISE CIGS TO VFR BY AFTN. SOME TSTMS MAY BE AROUND MONDAY BUT
CONFIDENCE IN TIMING OF CONVECTION IS NOT HIGH ATTM AND WILL
CONTINUE TO MONITOR TRENDS. LIGHT EASTERLY WINDS THIS EVENING
WILL BECOME LIGHT AND VARIABLE TONIGHT BEFORE TRANSITIONING
SOUTHERLY OR SOUTHEASTERLY MONDAY.
&&
.PREV DISCUSSION... /ISSUED 404 PM CDT SUN APR 29 2012/
SHORT TERM...THROUGH MONDAY AFTERNOON. UNFORTUNATELY...CONFIDENCE
IS BELOW AVERAGE DURING THE NEXT 24 HOURS REGARDING SEVERAL
ELEMENTS OF THE FORECAST...INCLUDING CLOUD/FOG TRENDS AND
THUNDERSTORMS/POSSIBLE SEVERE WEATHER CHANCES.
STARTING OFF WITH HERE AND NOW...19Z OBJECTIVE SURFACE ANALYSIS
INDICATES LIGHT EASTERLY BREEZES ACROSS MOST OF THE CWA...FLOWING
OUT OF A SURFACE HIGH CENTERED WELL TO THE NORTHEAST ACROSS THE
GREAT LAKES. THE CWA IS SITUATED WELL NORTH OF THE PRIMARY
REGIONAL SYNOPTIC EAST-WEST BOUNDARY/WARM FRONT...STRETCHED NEAR
THE OK/KS BORDER ACROSS SOUTHERN MO. ALOFT...WATER VAPOR IMAGERY
AND SHORT TERM MODEL DATA INDICATES A CLOSED 500MB LOW DRIFTING
NORTH OUT OF ND INTO CANADA...BUT WITH A TROUGH AXIS TRAILING
SOUTH-SOUTHWEST INTO THE NE/WY/CO BORDER AREA. AHEAD OF THIS
SYNOPTIC SCALE TROUGH AXIS...A LEAD SHORTWAVE IS IN THE PROCESS OF
EXITING THE CWA TO THE EAST...AND IS DRIVING ONGOING SHOWERS
ACROSS SOUTHEAST NEB. VISIBLE SATELLITE IMAGERY CONFIRMS WHY THE
TEMPERATURE FORECAST TODAY HAS BEEN FRUSTRATING...WITH AT LEAST
PARTIAL CLEARING DOMINATING SEVERAL COUNTIES WEST OF HIGHWAY
281...WHILE A SOLID LOW STRATUS DECK HAS STOOD FIRM ACROSS MUCH OF
THE CENTRAL/EAST...WITH A RENEWED NORTHWARD EXPANSION OF LOW
STRATUS NOW EVIDENT OUT OF NORTH CENTRAL KS. AS A RESULT...IT NOW
LOOKS LIKE MANY OF THESE CENTRAL/EASTERN COUNTIES MAY STRUGGLE TO
ATTAIN HIGHS IN THE MID-UPPER 50S...AT LEAST 5-10 DEGREES COOLER
THAN ORIGINALLY EXPECTED.
LATE THIS AFTERNOON THROUGH 00Z...WILL FOCUS THE MAIN CHANCES FOR
POSSIBLE SHOWER/STORM DEVELOPMENT WEST OF A LINE FROM
GREELEY-PLAINVILLE...WHERE CLEARING IS ALLOWING AT LEAST A FEW
HUNDRED J/KG OF 0-1KM MLCAPE TO BUILD. SHORT TERM REFLECTIVITY
PROGS FROM THE HRRR AND 12Z 4KM WRF-NMM SUPPORT THE POSSIBILITY OF
A FEW SHOWERS/STORMS DEVELOPING INTO THESE WESTERN ZONES BEFORE
DARK...AND ALTHOUGH NOT EXPECTING SEVERE WEATHER...A FEW INSTANCES
OF SMALL HAIL/GUSTY WINDS ARE NOT OUT OF THE QUESTION.
TURNING TO THE EVENING 00Z-06Z PERIOD...WILL KEEP LOW-END
THUNDERSTORM CHANCES GOING FOR MUCH OF NORTH CENTRAL KS...AND IN
NEB MAINLY WEST OF A GREELEY-ALMA LINE AS THE MAIN 500MB SHORTWAVE
AXIS SWINGS THROUGH THE CWA. AGAIN...SUPPOSE A FEW INSTANCES OF
SMALL HAIL NOT OUT OF THE QUESTION. FOR THE LATE NIGHT 06Z-12Z
PERIOD...KEPT LOW-END THUNDER CHANCES CONFINED TO A HANDFUL OF
FAR SOUTHWESTERN COUNTIES...IN CLOSEST PROXIMITY TO 850MB THETA-E
ADVECTION TIED TO A MODEST LOW LEVEL JET NOSING OUT OF WESTERN KS.
ALL THIS BEING SAID THOUGH...THE VAST MAJORITY OF THE CWA SHOULD
REMAIN DRY THROUGH THE NIGHT. TURNING TO OTHER OVERNIGHT
ISSUES...AFTER HAVING A ROUND OF LOCALLY DENSE FOG LAST
NIGHT...THERE ARE FAIRLY STRONG INDICATIONS IN NUMERICAL GUIDANCE
AND ALSO VISIBILITY PROBABILITY PROGS FROM THE SREF THAT ANOTHER
FAIRLY WIDESPREAD ROUND OF FOG SHOULD MATERIALIZE TONIGHT...THANKS
TO THE COMBINATION OF LIGHT WINDS AND A SATURATED BOUNDARY LAYER.
CONFIDENCE IN PLACEMENT WAS CERTAINLY NOT HIGH ENOUGH FOR A
HEADLINE YET...BUT WILL INSERT VISIBILITY BELOW 1 MILE INTO THE
GRIDS AND ALSO THE HWO. AS FOR LOW TEMPS...MAY END UP TOO COOL IF
A SOLID STRATUS BLANKET HOLDS FIRM...BUT WILL AIM FOR MID-UPPER
40S MOST AREAS.
TURNING TO MONDAY...OBVIOUSLY FOG COULD BE A CONCERN FOR THE FIRST
FEW HOURS AFTER SUNRISE. THEREAFTER...CONFIDENCE REMAINS UNUSUALLY
LOW IN THUNDERSTORM PROBABILITY/COVERAGE. THE GENERAL BIG PICTURE
INVOLVES A QUASI- ZONAL FLOW ALOFT...AS A LOW AMPLITUDE MID LEVEL
WAVE TRACKS FROM EASTERN CO INTO KS/SOUTHERN NEB. WITH WEAK
CAPPING EVIDENT IN FORECAST SOUNDINGS...AND CONTINUED 850MB
THETA-E ADVECTION...SEVERAL DETERMINISTIC MODELS SUCH AS THE
NAM/ECMWF/GFS ALL BRING STORMS INTO MUCH OF THE SOUTHWEST CWA
ALREADY IN THE MORNING...WHILE ON THE OTHER HAND...THE 4KM WRF-NMM
KEEPS THE MORNING CONVECTION-FREE. THEN DURING THE AFTERNOON...AN
EVEN STRONGER CONVECTIVE SIGNAL DEVELOPS IN SEVERAL DETERMINISTIC
MODELS...WHILE AGAIN THE 4KM REMAINS STRANGELY DRY. ALTHOUGH THE
ULTIMATE EXTENT OF DESTABILIZATION WILL BE STRONGLY INFLUENCED BY
HOW QUICKLY MORNING FOG/STRATUS VACATES...THE 18Z NAM ADVERTISES A
RESPECTABLE SEVERE WEATHER SETUP FOR THE MID-LATE AFTERNOON ACROSS
PARTS OF THE SOUTHERN CWA...BUT ESPECIALLY SOUTHERN ZONES WITH AT
LEAST 1500 J/KG 0-1KM MLCAPE...AND AROUND 40KT OF DEEP LAYER
SHEAR. ALTHOUGH THE OFFICIAL SPC DAY 2 SLIGHT RISK BARELY BRUSHES
THE FAR SOUTHERN CWA...WOULD NOT BE A BIT SURPRISED TO SEE THIS
EXTEND FARTHER NORTH ON THE UPCOMING DAY 1 PRODUCTS...AND WILL
INTRODUCE A SEVERE MENTION FOR HAIL/WIND IN THE HWO EXTENDING INTO
MONDAY EVENING. ALTHOUGH ONLY MODEST SHEAR IN THE LOWEST 1KM
SHOULD LIMIT A TORNADO THREAT...THIS POSSIBILITY IS ALSO NOT OUT
OF THE QUESTION NEAR THE NORTHWARD LIFTING INSTABILITY
GRADIENT/WARM FRONT IN KS ZONES. TEMPERATURE WISE MONDAY...STAYED
CLOSE TO GUIDANCE CONSENSUS...WHICH LOWERED MOST AREAS AT LEAST
2-3 DEGREES FROM PREVIOUS FORECAST INTO MAINLY THE 70-73 RANGE.
WOULD NOT BE SURPRISED THOUGH TO SEE WIDESPREAD CLOUDS ULTIMATELY
KEEP SOME AREAS IN THE 60S...JUST CAN/T SAY WHERE YET.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. THIS IS VERY COMPLEX
WEATHER PATTERN WITH NUMEROUS WEAK SHORT WAVES CROSSING OUR FORECAST
AREA RESULTING IN ON AND OFF AGAIN SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS. TEMPERATURES WILL BE WARM FOR THIS TIME OF YEAR WITH
HIGHS IN THE 70S AND 80S THROUGHOUT THE PERIOD. NORMAL HIGHS ARE ONLY
IN THE MID TO UPPER 60S.
MONDAY NIGHT...SEVERAL OF THE THUNDERSTORMS THAT DEVELOP DURING THE
DAY ON MONDAY MAY PERSIST INTO THE EVENING/OVERNIGHT HOURS. A FEW OF
THESE THUNDERSTORMS MAY BE SEVERE...PRIMARILY SOUTH OF INTERSTATE 80.
TUESDAY...TEMPERATURES WARM WITH SOUTHERLY FLOW INTO THE 80S ACROSS
THE ENTIRE FORECAST AREA. THE ATMOSPHERE SHOULD BE PRETTY UNSTABLE BY
AFTERNOON AND A WEAK SHORT WAVE WILL BE MOVING ACROSS THE AREA. AM
ONLY GOING WITH A SLIGHT CHANCE OF THUNDERSTORMS DUE TO THE LIMITED
FORCING...BUT IF STORMS FORM THEY COULD CERTAINLY BE SEVERE GIVEN
APPRECIABLE DEEP LAYER SHEAR AND INSTABILITY.
WEDNESDAY INTO THURSDAY...A SFC FRONTAL BOUNDARY WILL STALL OUT
ACROSS OUR CWA AND MEANDER A BIT BACK AND FORTH ACROSS OUR CWA.
THERE WILL BE AT LEAST MODERATE INSTABILITY AND WITH WEAK UPPER
WAVES PASSING THROUGH WE COULD POP A FEW THUNDERSTORMS. WEAK DEEP
LAYER SHEAR MAY ACTUALLY BE ONE OF THE HINDERING FACTORS FOR SEVERE
WEATHER...BUT MODERATE INSTABILITY MAY BE ENOUGH TO ALLOW A FEW
STORM TO REACH SEVERE WEATHER THRESHOLDS SHOULD THEY FORM.
FRIDAY THROUGH SUNDAY. FRIDAY IS THE ONLY DRY DAY IN THE CURRENT
FORECAST AND EVEN THAT CAN NOT BE GUARANTEED. A STRONG UPPER LEVEL
TROUGH WILL BEGIN TO DEVELOP ACROSS THE WESTERN CONUS BY NEXT WEEKEND
AND WE COULD SEE A FEW CHANCES OF THUNDERSTORMS OUT AHEAD OF THIS
TROUGH...BUT BETTER CHANCES FOR THUNDERSTORMS MIGHT HOLD OFF UNTIL
JUST BEYOND THE END OF THIS FORECAST PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS RALEIGH NC
737 PM EDT SUN APR 29 2012
.SYNOPSIS...
A STALLED FRONT OVER SOUTH CAROLINA WILL RETURN NORTHWARD AS A WARM
FRONT OVER WESTERN PORTIONS OF THE STATE THIS EVENING AS HIGH
PRESSURE STRENGTHENS AND PROGRESSES SOUTHWARD ALONG THE MID ATLANTIC
COAST.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM SUNDAY...
OVERVIEW:
AN H5 RIDGE CENTERED OVER THE WESTERN TN/OH VALLEYS AT 15Z WILL
PROGRESS EASTWARD TO THE SPINE OF THE APPALACHIANS BY 00-06Z
TONIGHT...RESULTING IN MODEST H5 HEIGHT RISES OVER THE MID-ATLANTIC
TODAY/TONIGHT. A SURFACE RIDGE AXIS EXTENDING SOUTH FROM THE
MID-ATLANTIC INTO THE CAROLINAS AT 15Z WILL WEAKEN IN WESTERN
PORTIONS OF THE STATE WHERE A WEAK TROUGH WILL DEVELOP. HOWEVER...
THE SURFACE RIDGE AXIS WILL STRENGTHEN TODAY/TONIGHT IN EASTERN
PORTIONS OF THE STATE IN ASSOC/W PRESSURE RISES ALONG THE MID-
ATLANTIC COAST...DUE TO HEIGHT RISES/SUBSIDENCE ALOFT IN ADVANCE OF
THE AFOREMENTIONED RIDGE. A SURFACE FRONT STALLED JUST S/SE OF THE
AREA OVER CENTRAL/SOUTHERN SOUTH CAROLINA AT 15Z IS PROGGED TO
ASSUME A NW-SE ORIENTATION TODAY/TONIGHT...LIFTING NORTHWARD INTO
PORTIONS OF THE WESTERN NC PIEDMONT/FOOTHILLS AND EXTENDING
SOUTHEAST IN VICINITY OF CAPE FEAR/WILMINGTON.
PRECIP CHANCES THIS AFT/EVE:
A WEAK UPPER LEVEL DISTURBANCE WAS NOTED IN WV IMAGERY/RUC DATA IN
SOUTHWEST VA AT 15Z. THE LATEST RUC SHOWS THIS FEATURE PROGRESSING
SOUTHEAST VIA NW FLOW ALOFT THROUGH THE NORTHEAST COASTAL PLAIN BY
18-21Z AND OFFSHORE THE NC OBX BY 21-00Z. GIVEN UNFAVORABLE
THERMODYNAMICS IN ADVANCE OF THIS FEATURE IN THE COASTAL PLAIN
(CLOUDY/COOL/STABLE) THROUGH 18-21Z...EXPECT DRY CONDITIONS TO
PREVAIL EAST OF HWY 1 THIS AFT/EVE. MODERATE INSTABILITY IS EXPECTED
THIS AFTERNOON IN FAR WESTERN PORTIONS OF THE STATE...THOUGH MLCAPE
VALUES SHOULD REMAIN ON THE MARGINAL SIDE (500-1000 J/KG) IN THE
WESTERN PIEDMONT...CLOSER TO THE DRIER SFC RIDGE AXIS TO THE EAST.
DESTABILIZATION IN THE WEST WILL BE AIDED BY INCREASING BOUNDARY
LAYER MOISTURE (ASSOC/W THE FRONT PROGRESSING NORTHWARD INTO WESTERN
NC) IN THE PRESENCE OF STEEP MID-LEVEL LAPSE RATES (7-8 C/KM) AND
CLEAR SKIES. HOWEVER...SUBSIDENCE IN THE WAKE OF THE AFOREMENTIONED
UPPER LEVEL DISTURBANCE ALONG WITH WEAK SYNOPTIC HEIGHT RISES IN
ADVANCE OF THE H5 RIDGE APPROACHING FROM THE WEST WILL BE
UNSUPPORTIVE OF PRECIP...AND LOW-LEVEL FORCING WILL BE CONFINED TO
BROAD WARM ADVECTION AND WEAK/SHALLOW LOW-LEVEL CONVERGENCE...WITH
THE RELATIVE BEST LOW-LEVEL FORCING CONFINED WEST OF I-77. IF ISOLD
CONVECTION DEVELOPS IN THE MOUNTAINS/FOOTHILLS AFTER 21Z...IT IS
CONCEIVABLE THAT IT COULD PROGRESS EAST/SE INTO PORTIONS OF THE NW
PIEDMONT BETWEEN 21-02Z THIS AFT/EVE VIA SPEEDY WESTERLY/WNW FLOW
ALOFT. THE LATEST 12Z WRF-NMM INDICATES THIS SCENARIO IS AT LEAST
POSSIBLE...AND WITH THAT IN MIND...WILL INTRODUCE A SLIGHT CHANCE OF
SHOWERS/STORMS TO THE FAR WESTERN PIEDMONT LATE THIS AFT/EVE.
IT IS INTERESTING THAT SUFFICIENT INSTABILITY AND 0-6 KM SHEAR MAY
BE PRESENT ON THE EASTERN PERIPHERY OF THE H5 RIDGE IN THE WESTERN
PIEDMONT TO SUPPORT A VERY LOW-END CONDITIONAL SEVERE THREAT LATER
THIS AFT/EVE...THOUGH A PROFOUND LACK OF FORCING AND THE PRESENCE OF
A DRY AIRMASS ALOFT (ASSOC/W AN EML EXTENDING EAST INTO THE AREA)
WILL MAKE IT DIFFICULT FOR ANY UPDRAFTS TO SURVIVE/PERSIST... SHOULD
ANY DEVELOP OR ADVECT INTO THE WESTERN PIEDMONT IN THE FIRST PLACE.
PRECIP CHANCES TONIGHT:
AS THE H5 RIDGE AXIS PROGRESSES EAST TO THE SPINE OF THE
APPALACHIANS TONIGHT...IT WILL BECOME INCREASINGLY DIFFICULT FOR ANY
UPSTREAM SHORTWAVES/MCVS (PROGRESSING EAST ATOP THE RIDGE) TO TRACK
INTO CENTRAL NC...WITH A MORE LIKELY TRACK FURTHER NORTH IN THE
MID-ATLANTIC. AS A RESULT...LITTLE OR NO UPPER SUPPORT WILL BE
PRESENT OVERNIGHT...THOUGH WEAK LOW-LEVEL WARM ADVECTION WILL BE
PRESENT. GIVEN THE CONTINUED PRESENCE OF AN ELEVATED MIXED LAYER
(ALBEIT MODIFIED)...EXPECT AT LEAST MARGINAL ELEVATED INSTABILITY TO
BE PRESENT OVERNIGHT. WITH THE ABOVE IN MIND...WILL CONTINUE TO
INDICATE A SLIGHT CHANCE OF SHOWERS OVERNIGHT IN ASSOC/W WARM
ADVECTION IN THE PRESENCE OF ELEVATED INSTABILITY. THUNDER CANNOT BE
RULED OUT...PRIMARILY IN THE WEST/NW PIEDMONT...THOUGH IT SEEMS
UNLIKELY IN THE ABSENCE OF ANY UPPER LEVEL SUPPORT.
LOWS TONIGHT:
AS THE SFC-H85 RIDGE STRENGTHENS OVER EASTERN NC/VA TONIGHT...
LOW-LEVEL FLOW WILL VEER TO THE EAST/SE AND ADVECT A MOIST MARITIME
AIRMASS INTO CENTRAL NC. WIDESPREAD LOW CLOUD COVER IS EXPECTED TO
ADVECT INTO OR RE-DEVELOP OVER THE AREA...THICKER/LOWER WEST OF I-95
IN CLOSER PROXIMITY TO BETTER LOW-LEVEL MOISTURE IN VICINITY OF THE
AFOREMENTIONED FRONTAL ZONE. EXPECT LOWS TO RANGE FROM THE MID/UPPER
50S EAST OF I-95 CENTRAL/NE COASTAL PLAIN TO THE UPPER 50S AND LOWER
60S ELSEWHERE...WARMEST SANDHILLS AND WEST/SW PIEDMONT. -VINCENT
&&
.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 345 PM SUNDAY...
OVERVIEW:
THE H5 RIDGE AXIS WILL PROGRESS EAST INTO THE MID-ATLANTIC AND
CAROLINAS ON MONDAY AS SHORTWAVE ENERGY TRACKS NORTHEAST THROUGH THE
GREAT LAKES INTO CANADA. THE RIDGE IS PROGGED TO WEAKEN MONDAY NIGHT
AS ADDITIONAL SHORTWAVE ENERGY PROGRESSES INTO THE MID-ATLANTIC FROM
THE SOUTHWEST. CENTRAL NC WILL BE ON THE NORTHERN PERIPHERY OF THE
RIDGE (CENTERED OVER THE DEEP SOUTH/SOUTHEAST STATES) ON MONDAY...IN
THE PRESENCE OF WESTERLY FLOW ALOFT. WESTERLY FLOW ALOFT WILL
STRENGTHEN MONDAY NIGHT AS THE RIDGE WEAKENS AND THE HEIGHT GRADIENT
TIGHTENS FROM THE NORTH. IN THE LOWER LEVELS...A LOW PRESSURE SYSTEM
TRACKING NORTHEAST THROUGH THE GREAT LAKES WILL PUSH HIGH PRESSURE
OFFSHORE THE MID-ATLANTIC/CAROLINA COAST ON MONDAY. THE RESULTING
SOUTHERLY RETURN FLOW WILL ALLOW THE NW-SE ORIENTED FRONTAL ZONE IN
IN PLACE OVER THE AREA TONIGHT TO MOVE NORTHEAST THROUGH THE ENTIRE
AREA AS A WARM FRONT DURING THE DAY MONDAY...WITH A WARM/MOIST
SOUTHERLY RETURN FLOW PERSISTING MONDAY NIGHT.
TEMPERATURES:
CHALLENGING FCST. EXPANSIVE LOW-LEVEL CLOUD COVER IS EXPECTED TO BE
IN PLACE SUNRISE MONDAY MORNING. FORECAST SOUNDINGS INDICATE THAT
THIS LOW STRATUS MAY TAKE AT LEAST SEVERAL HOURS TO LIFT AND SCATTER
OUT...PERHAPS NOT UNTIL 18-21Z IN SOME LOCATIONS. HIGH TEMPS WILL
DEPEND PRIMARILY ON THE TIMING OF CLOUD COVER EROSION. 1000-850 MB
THICKNESSES ARE PROGGED TO BE IN THE 1390-1405 METER RANGE ON
MONDAY... LOWEST NE COASTAL PLAIN AND HIGHEST W/SW PIEDMONT. AT THIS
TIME...WILL INDICATE HIGHS RANGING FROM THE MID 70S NE TO UPPER 70S/
LOWER 80S (76-81F) ELSEWHERE...WARMEST IN THE FAR SE PIEDMONT. GIVEN
WARM ADVECTION AND THE EXPECTED DEVELOPMENT OF LOW STRATUS AGAIN IN
MOST LOCATIONS MONDAY NIGHT...ANTICIPATE WARMER LOW TEMPERATURES...
IN THE LOWER 60S.
PRECIPITATION CHANCES:
DIFFICULT PRECIP FCST. DIURNAL DESTABILIZATION ON MONDAY WILL HIGHLY
DEPEND ON WHEN EXPANSIVE LOW-LEVEL CLOUD COVER LIFTS/SCATTERS OUT
AND WHERE THE BEST BOUNDARY LAYER MOISTURE WILL BE PRESENT IN THE
WAKE OF THE WARM FRONT PROGRESSING NE/NNE THROUGH THE AREA. GIVEN
THAT THE WARM FRONT WILL PROGRESS THROUGH THE WEST/SW PIEDMONT
FIRST...AREAS WEST OF HIGHWAY 1 WILL DESTABILIZE THE MOST ON MONDAY.
MODEL GUIDANCE IS INDICATING MLCAPE VALUES AS HIGH AS 1500-2000 J/KG
IN THE WESTERN PIEDMONT...OWING TO TEMPS IN THE UPPER 70S AND
DEWPOINTS IN THE LOWER 60S IN THE PRESENCE OF A MODIFIED EML WITH
MID-LEVEL LAPSE RATES ON THE ORDER OF 7-7.5 C/KM. FURTHER EAST WHERE
BOUNDARY LAYER MOISTURE WILL BE LOWER...MLCAPE VALUES WILL GENERALLY
RANGE FROM 500-1500 J/KG. W/REGARD TO FORCING...ALTHOUGH AN H5 RIDGE
AXIS WILL EXTEND NORTHWARD (FROM GA/FL) INTO THE CAROLINAS/
MID-ATLANTIC ON MONDAY...CENTRAL NC WILL REMAIN ON THE NORTHERN
PERIPHERY OF THE RIDGE IN WESTERLY FLOW ALOFT...AND SOME UPPER
FORCING IN THE FORM OF MINOR SHORTWAVES WILL BE POSSIBLE.
HOWEVER...THE TIMING AND EVOLUTION OF THESE FEATURES ARE DIFFICULT
TO ANTICIPATE AT THIS TIME. GIVEN A PATTERN OF SOUTHERLY/SE RETURN
FLOW...LOW-LEVEL FORCING WILL BE CONFINED TO UPSLOPE FLOW IN THE
FOOTHILLS/MOUNTAINS...AND TO THE SEABREEZE AND/OR DIFFERENTIAL
HEATING BOUNDARIES IN CENTRAL/EASTERN NC. GIVEN A FAIR AMOUNT OF
UNCERTAINTY W/REGARD TO WHETHER OR NOT SUFFICIENT FORCING WILL BE
PRESENT...WILL INDICATE A SLIGHT CHANCE OF SHOWERS/STORMS OVER THE
ENTIRE AREA MON AFT/EVE. FOR MONDAY NIGHT...GIVEN AN OVERALL LACK OF
FORCING AND A RELATIVELY LESS FAVORABLE (THAN TONIGHT) THERMODYNAMIC
ENVIRONMENT (I.E. VERY LITTLE IF ANY ELEVATED INSTABILITY)... HAVE
OPTED TO KEEP THE FCST DRY. -VINCENT
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 301 PM SUNDAY...
...SUMMER-LIKE TEMPERATURES AND HUMIDITIES EXPECTED TUESDAY THROUGH
THE END OF THE WEEK...
AS WE BEGIN A NEW MONTH ON TUESDAY... IT WILL BE LIKE FLIPPING A
SWITCH FROM MILD TO HOT. THE OVERALL MID-UPPER LEVEL FLOW PATTERN IS
A HIGH CONFIDENCE FORECAST FOR THE REGION AS MODELS ARE IN EXCELLENT
AGREEMENT IN THE DEVELOPMENT OF A MODERATELY STRONG UPPER LEVEL
RIDGE OVER THE SOUTHEASTERN UNITED STATES TUESDAY AND WEDNESDAY.
THE UPPER RIDGE IS FORECAST TO PERSIST WELL INTO THE END OF THE
WEEK. THE UPPER RIDGE AXIS IS FORECAST TO PEAK OVER NC/SC BY
WEDNESDAY INTO THURSDAY... THEN SHIFT WESTWARD IN TIME FRIDAY INTO
SUNDAY. THE BOTTOM LINE... EXPECT A DRAMATIC SHIFT FROM MILD AND
MOIST CONDITIONS FROM THE PAST FEW WEEKS... TO SUMMERTIME CONDITIONS
TUESDAY THROUGH THE REST OF THE WEEK.
THERE ARE INDICATIONS THAT THE HOT/HUMID WEATHER WILL LAST 5-6
DAYS... THEN IT SHOULD BE FOLLOWED BY A SIGNIFICANT COOL DOWN LATE
NEXT WEEKEND OR AROUND MAY 6-9. (IF THE MODELS ARE CORRECT IN THE
LONGER TERM FORECAST SHIFT IN THE UPPER RIDGE WESTWARD BACK TO THE
PLAINS - ALLOWING THE CARVING OUT OF A H5 TROUGH ALONG THE EASTERN
SEABOARD).
THEREFORE THIS WEEK... EXPECT HOT AND UNSEASONABLY HUMID
CONDITIONS... WITH ONLY A SLIGHT CHANCE OF AN AFTERNOON OR EVENING
THUNDERSTORM BEYOND TUESDAY.
SENSIBLE WEATHER WILL START WITH CONDITIONS BECOMING VERY WARM AND
HUMID TUESDAY AS THE LEAD WARM FRONT LIFTS NORTH OF OUR REGION.
THERE IS A POTENTIAL FOR SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS AS MODELS INDICATE THE POTENTIAL FOR A VORTICITY
MAXIMUM TO RIDE A TOP THE BUILDING MID-UPPER LEVEL RIDGE OVER NC/VA
DURING MAXIMUM HEATING. FOR NOW... IT IS TOO EARLY TO LATCH ONTO
SUCH A FEATURE WITH ANY CONFIDENCE IN THE MODELS. HOWEVER... THIS
POTENTIAL WILL BE WATCHED. OTHERWISE... DIFFERENTIAL HEATING ALONG
THE EASTERN SLOPES OF THE MOUNTAINS SHOULD LEAD TO AT LEAST
SCATTERED THUNDERSTORMS TUESDAY AFTERNOON IN THE INCREASINGLY HUMID
BOUNDARY LAYER OVER NC/SW VA. SOME OF THESE MAY MOVE OFF OR DEVELOP
INTO THE PIEDMONT AS MODELS DO FAVOR A SURFACE TROUGH DEVELOPMENT IN
THE PIEDMONT DURING THE AFTERNOON. HIGHS WILL SOAR INTO THE MID TO
UPPER 80S. DEW POINTS SHOULD RISE TO BETWEEN 60-65... MAKING IT FEEL
LIKE JUNE OR EARLY JULY. WE WILL FORECAST 20-30 POP AND WAIT/SEE HOW
THE MODELS FORECAST ANY VORT MAX FOR TUESDAY TO AID IN CONVECTIVE
POTENTIAL.
AFTER THE SCATTERED CONVECTION POTENTIAL ENDS TUESDAY EVENING... WE
EXPECT THE MID-UPPER LEVEL RIDGING TO BE STRONG ENOUGH TO SUPPRESS
CONVECTIVE DEVELOPMENT IN THE ABSENCE OF ANY FOCUSING MECHANISMS
EVEN WITH DECENT LOW LEVEL MOISTURE AND HEAT. EXPECT GENERALLY WARM
DRY SUBSIDENCE IN THE MID LEVELS. WEDNESDAY THROUGH FRIDAY... MOSTLY
CLEAR MILD NIGHTS AND MOSTLY SUNNY HOT DAYS. DAILY TEMPERATURES
SHOULD AVERAGE A GOOD 10 DEGREES ABOVE NORMAL. NIGHTTIME LOWS A GOOD
10-15 DEGREES ABOVE NORMAL. LOWS SHOULD BE IN THE LOWER TO MID 60S
EACH DAY. HIGHS GENERALLY IN THE 85-90 RANGE.
SATURDAY AND SUNDAY... THE MID-UPPER HEIGHTS ARE FORECAST TO BEGIN
TO LOWER SOMEWHAT OVER THE SE WHICH SHOULD ALLOW DAILY TEMPERATURES
TO BACK OFF A FEW DEGREES. THE CHANCE OF CONVECTION SHOULD INCREASE
AT SOME POINT AS THE TROUGH DEVELOPS. HOWEVER... WE WILL KEEP ANY
MENTION OF SHOWERS OR THUNDERSTORMS ISOLATED... AND MAINLY LATE DAY
UNTIL A MORE DEFINITIVE TIMING OF AN ACTUAL COLD FRONT OR OTHER
FOCUS CAN BE PROJECTED. LOWS IN THE MID 60S. HIGHS IN THE LOWER TO
MID 80S.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 730 PM SUNDAY...
24 HOUR TAF PERIOD:
THE AVIATION FORECAST PROBLEM FOR THE 24 HOUR TAF PERIOD WILL BE THE
ONSET OF LOW STRATUS WHICH WILL CAUSE CONDITIONS TO GRADUALLY
DETERIORATE TO IFR OVERNIGHT SUNDAY NIGHT INTO MONDAY. EXPECT
CEILINGS TO DROP FIRST IN THE EAST TO MVFR BY 6Z AND IFR AT ALL
SITES BY 9Z WITH VISIBILITIES AT 4-5 MILES. ON MONDAY CEILINGS WILL
GRADUALLY IMPROVE STARTING WITH KRWI LIFTING TO MVFR AFTER 12Z. ALL
OTHER SITES SHOULD REMAIN IFR INTO THE AFTERNOON...FINALLY LIFTING
TO MVFR AROUND OR JUST BEFORE 18Z. BY 21Z ALL SITES ARE EXPECTED TO
RETURN TO LOW VFR CONDITIONS.
AS SURFACE HIGH PRESSURE DEVELOPS AND MOVES OFF OF THE DELMARVA
COAST MONDAY...WINDS WILL GRADUALLY SHIFT FROM A MORE
EAST/SOUTHEASTERLY DIRECTION TO A MORE SOUTHERLY DIRECTION BY
MID-AFTERNOON. AN INCREASE IN THE SURFACE PRESSURE GRADIENT ACROSS
CENTRAL NORTH CAROLINA SHOULD ALLOW SUSTAINED WINDS TO INCREASE TO
NEAR OR JUST ABOVE 10 KNOTS AT ALL SITES TOMORROW AFTERNOON WITH
LITTLE TO NO GUSTING. WHILE PRECIPITATION...IN THE FORM OF SCATTERED
THUNDERSTORMS ARE POSSIBLE TOMORROW AFTERNOON THERE IS VERY LOW
CONFIDENCE IN THE FORECAST AT THIS TIME AND ALL MENTION OF SHOWERS
OR THUNDERSTORMS WILL BE LEFT OUT OF THE 00Z TAF PACKAGE.
LONG TERM:
SUB VFR CONDITIONS DUE TO STRATUS WILL ONCE AGAIN BE POSSIBLE ON
TUESDAY MORNING...QUICKLY LIFTING BY LATE MORNING/EARLY AFTERNOON.
VFR CONDITIONS ARE LARGELY EXPECTED FOR THE LONG TERM ALTHOUGH
DIURNAL SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE FOR THE REMAINDER
OF THE WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...ELLIS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
245 PM EDT SAT APR 28 2012
.SYNOPSIS...
A COLD FRONT WILL MEANDER ABOUT THE REGION THROUGH EARLY MONDAY. A
SUMMERTIME PATTERN WILL THEN DEVELOP AND CONTINUE THROUGH THE
REMAINDER OF THE PERIOD.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 3:00 PM SATURDAY...CLOUDS ALONG AND NORTH OF THE STALLED FRONT
HAVE BEEN EXCEEDINGLY RESILIENT TO BURNING OFF DESPITE RELATIVELY
STEEP LATE-APRIL SUN ANGLES AND THE LACK OF PRECIPITATION. WITH THE
SUN ALREADY PASSING INTO THE WESTERN SKY WE HAVE TO ENTERTAIN THE
NOTION THAT CLOUDS WILL PERSIST SOLIDLY THROUGH SUNSET IN THE
LUMBERTON AND BENNETTSVILLE AREAS WITH HIGHS PERHAPS REACHING THE
LOWER 70S BEFORE FALLING AGAIN THIS EVENING. THE FRONT HAS BECOME
CONCOMITANT WITH THE SEABREEZE AT THE COAST AND APPEARS TO LIE ALONG
A LINE FROM SOUTHPORT TO GREEN SEA TO MARION AND FLORENCE. THE
BOUNDARY WILL SLOWLY MOVE NORTH TONIGHT...FINALLY LIFTING THROUGH
LUMBERTON AROUND MIDNIGHT. EAST TO NORTHEAST WINDS ON THE COOL SIDE
OF THE BOUNDARY WILL TURN SOUTHERLY. THERE SHOULD NOT BE AN INCREASE
IN WIND SPEEDS DOWN HERE AT THE SURFACE BEHIND THE FRONT DUE TO ONLY
A WEAK LOW LEVEL JET ALOFT...15-20 KT IN THE 1000-2000 FT LAYER.
THIS WILL HOPEFULLY BE JUST ENOUGH WIND TO PREVENT WIDESPREAD FOG
DEVELOPMENT BUT WILL INSTEAD FAVOR THE FORMATION OF LOW STRATUS
CLOUDS AFTER MIDNIGHT.
ALTHOUGH SPC AND RUC MESOANALYSIS SHOW SURFACE-BASED CAPE ON THE
ORDER OF 1000-1500 J/KG ACROSS INLAND SOUTH CAROLINA...DRY
ENVIRONMENTAL CONDITIONS BETWEEN THE LCL AND LFC AND THE NOTABLE
LACK OF ANY UPPER AIR IMPULSES MEAN THERE IS ONLY A TINY CHANCE FOR
A SHOWER OR THUNDERSTORM TO FORM BETWEEN NOW AND SUNSET. IF ANYTHING
WERE TO FORM IT WOULD LIKELY BE NEAR THE INTERSECTION OF THE
SEABREEZE AND THE SYNOPTIC FRONT...SOMEWHERE FROM MARION AND TABOR
CITY TO LAKE WACCAMAW. LOWS TONIGHT SHOULD FALL INTO THE LOWER TO
MID 60S...7-10 DEGREES ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3:00 PM SATURDAY...THE PERSISTENT BAROCLINIC ZONE WILL
CONTINUE TO BE AN ISSUE THROUGH THE PERIOD AS IT MAKES ANOTHER RUN
TO THE SOUTH LATER SUNDAY AS THE MID LEVEL RIDGE AMPLIFIES ACROSS
THE MIDWEST. FORECAST CHALLENGE WILL PRIMARILY BE POPS.
FOR SUNDAY...MIXED LAYER CAPE VALUES INCREASE TO APPROXIMATELY 2000K
J/KG PER THE GFS ACROSS NORTHERN ZONES AS THE FRONT SLIPS SOUTH.
THIS INSTABILITY ALONG WITH THE FORCING WITH A SUBTLE SHORTWAVE
THROWN IN FOR GOOD MEASURE WARRANTS LOWER CHANCE POPS FOR THESE
AREAS LATE SUNDAY INTO THE EVENING HOURS.
POPS DIMINISH WITH THE LOSS OF DAYTIME HEATING SUNDAY NIGHT INTO
EARLY MONDAY BUT THE OVERCAST SKIES...MOISTURE TRAPPED UNDER A
CONSIDERABLE SUBSIDENCE INVERSION WILL CONTINUE TO INCREASE
SOUTHWARD.
MONDAY IS A TRANSITION DAY AS THE FRONT DISSIPATES AS THE SOUTHERLY
FLOW DEVELOPS. HOWEVER THIS WILL TAKE SOME TIME AND THE INVERSION
REMAINS PRESENT MOST OF THE DAY AND ALTHOUGH THE GFS AND NAM ARE
DEVELOPING A LITTLE LIGHT QPF...INDICATIONS ARE THIS IS THE
AFOREMENTIONED MOISTURE/STRATUS DECK.
TEMPERATURE GUIDANCE HAS WARMED SLIGHTLY AND THE MAIN CHALLENGE
APPEARS TO BE MONDAY MORNING LOWS AS THE CLOUD COVER WILL BE
INCREASING AND IT APPEARS THE BEST STRATEGY WILL BE TO ADD A DEGREE
OR TWO TO THE NUMBERS.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 3:00 PM SATURDAY...CONDITIONS WILL REMAIN LARGELY RAIN-FREE
THROUGH THE LONG TERM AS AN UPPER LEVEL RIDGE AXIS BUILDS ACROSS THE
EAST COAST. SURFACE HIGH PRESSURE WILL SIMILARLY SHOW LITTLE
MOVEMENT ACROSS THE WEST ATLANTIC. THIS LATTER FEATURE WILL IMPORT
WARM AND MOIST AIR ACROSS THE SOUTHEASTERN U.S. LEADING TO SLIGHTLY
WARM TEMPERATURES BY DAY AND EVEN MORESO WARMTH DURING THE NIGHTTIME
HOURS AS MOISTURE ACTS AS A LIMITING FACTOR FOR COOLING. THIS LOW
LEVEL MOISTURE PAIRED WITH THE WARM WILL AT SOME POINT TRY TO START
FIRING DIURNAL CONVECTION ALONG THE SEA BREEZE. THE SUBSIDENCE
ASSOCIATED WITH THE RIDGING ALOFT WILL KEEP THIS ACTIVITY ISOLATED
ENOUGH TO PRECLUDE BEING PUT IN THE FORECAST AT THIS TIME HOWEVER.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
AS OF 18Z...AREAS OF MVFR AT KILM/KFLO/KLBT WILL GRADUALLY IMPROVE
THROUGH THE NEXT 1-3 HOURS. CONDITIONS LIKELY REVERTING BACK TO
MVFR/IFR AFTER 00-04Z.
THOUGH FOG QUICKLY BURNED OFF THIS MORNING...LOWERED CIGS CONTINUE
TO LINGER ALONG AND NORTH OF THE STATIONARY FRONT AT KILM/KFLO/LBT.
VISIBLE SATELLITE IMAGERY DEPICTS SIGNS OF THESE LOW CLOUDS
BEGINNING TO BURN OFF...THUS EXPECT CONDITIONS TO IMPROVE WITHIN THE
NEXT HOUR OR TWO. WINDS WILL RANGE FROM NORTHEAST TO SOUTHEAST
THROUGH EARLY AFTERNOON WITH SUSTAINED WINDS 8 KTS. WINDS WILL
GRADUALLY VEER TO PREDOMINANTLY SOUTH-SOUTHEAST AT ALL SITES BY THIS
AFTERNOON WITH THE ANTICIPATED SEA BREEZE. CANNOT RULE OUT AN
ISOLATED SHOWERS/TS THIS AFTERNOON...ESPECIALLY IN AREAS NEAR THE
SEA BREEZE...POSSIBLY AFFECTING KILM. LATER TONIGHT INTO THE
OVERNIGHT HOURS...GIVEN ABUNDANT LOW LEVEL MOISTURE DEPICTED BY
MODELS EXPECT LOW LEVEL STRATUS TO DEVELOP CREATING IFR/LIFR
RESTRICTIONS THROUGH THE 14-15Z SUNDAY. WINDS ASSOCIATED WITH LOW
LEVEL JET WILL LIKELY INHIBIT ANY FOG DEVELOPMENT...THOUGH IF WINDS
BECOME LIGHT CANNOT RULE OUT BRIEF PATCHY FOG. ANTICIPATE LOW LEVEL
STRATUS TO BURN OFF THROUGHOUT THE MORNING HOURS...RETURNING TO VFR
AROUND 15Z OR SOON THEREAFTER.
EXTENDED OUTLOOK...MVFR OR BRIEF IFR VSBYS IN MORNING FOG
POSSIBLE MONDAY THROUGH WEDNESDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 3:00 PM SATURDAY...THE FRONT HAS MOVED VERY LITTLE DURING THE
DAYLIGHT HOURS...STILL STALLED FROM THE CAPE FEAR VICINITY INLAND
ACROSS EXTREME NORTHERN SOUTH CAROLINA. THE AFTERNOON SEABREEZE HAS
MADE PRECISE FRONTAL ANALYSIS DIFFICULT WHERE SOUTHEAST WINDS HAVE
DEVELOPED NEAR THE COAST. MODELS ARE ALMOST UNANIMOUS WITH THEIR
DEPICTIONS OF THE FRONT MOVING SLOWLY NORTH TONIGHT...FINALLY
REACHING TOPSAIL ISLAND A FEW HOURS AFTER SUNSET. SOUTH WINDS WILL
OVERSPREAD THE AREA WITH SPEEDS INCREASING TO 10-15 KT. IT APPEARS
DRY WEATHER WILL CONTINUE THROUGH THE NIGHT.
SEAS ARE RUNNING A BIT HIGHER THAN WAVE MODELS HAD FORECAST...
GENERALLY 2-3 FT WITH THE LARGEST WAVES NEAR AND EAST OF CAPE FEAR.
SPECTRAL WAVE PLOTS FROM THE FRYING PAN SHOALS BUOY SHOW DOMINANT
PERIODS AROUND 6 SECONDS...WITH VIRTUALLY NO SWELL ENERGY NOTED.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3:00 PM SATURDAY...
INITIALLY WINDS WILL CONTINUE FROM THE SOUTHWEST ACROSS ALL WATERS
AND WITH THE RESULTANT SEA BREEZE BACKING WINDS LATE SUNDAY
MORNING AND AFTERNOON. A BACKDOOR FRONT WILL MOVE INTO THE NORTH
CAROLINA WATERS LATE SUNDAY AFTERNOON AND CONTINUE SOUTH TO SOUTH
SANTEE BY EARLY MONDAY. THE FRONT WILL DISSIPATE AND WINDS WILL
VEER TO SOUTH/SOUTHEAST BY MONDAY EVENING. THE STRONGEST WINDS
OCCUR EARLY MONDAY AROUND 15 KNOTS BUT ANY BRIEF SURGE MAY
INCREASE SPEEDS SLIGHTLY MORE. SEAS REMAIN RELATIVELY BENIGN
CITING THE WINDS. 2-3 FEET INITIALLY WILL INCREASE FROM THE NORTH
TO A RANGE OF 2-4 FEET.
LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 3:00 PM SATURDAY...WEST ATLANTIC HIGH PRESSURE THE DOMINANT WIND
MAKER THROUGH THE LONG TERM PERIOD. A SOUTHERLY COMPONENT WILL THUS
BE OMNIPRESENT ALTHOUGH SOME VARIATION BETWEEN SOUTHEASTERLY AND
SOUTHWESTERLY MAY OCCUR. CURRENTLY A SHIFT FROM S OR SE TO SW
EXPECTED TO OCCUR BETWEEN TUE AND WED AS RIDGE AXIS OF THE PARENT
HIGH SINKS SOUTH OF THE REGION. THIS WILL LIKELY BE THE ONLY MINOR
VARIATION THROUGH THE PERIOD. LITTLE REFLECTION IN OVERALL WAVE
HEIGHT EXPECTED AND A 2 TO 3 FT FORECAST WILL HOLD FOR MOST OF THE
VALID TIME.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SHK
NEAR TERM...TRA
SHORT TERM...SHK
LONG TERM...MBB
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
844 PM EDT SUN APR 29 2012
.SYNOPSIS...
A WARM FRONT WILL BEGIN TO LIFT NORTH ACROSS OUR AREA LATE TONIGHT
AND MONDAY. THIS WILL BRING MUCH WARMER TEMPERATURES TO OUR AREA.
DISTURBANCES RIDING EASTWARD ALONG THE FRONT WILL BRING OCCASIONAL
CHANCES FOR SHOWERS AND THUNDERSTORMS THROUGHOUT THE WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
HIGH CLOUDS ASSOCIATED WITH WEAKENING CONVECTION TO OUR
WEST CONTINUES TO PRODUCE MOSTLY CLOUDY SKIES ACROSS OUR AREA.
ELEVATED INSTABILITY...AND WEAK 850 HPA CONVERGENCE BOUNDARY
IS SLOWLY MAKES ITS WAY NORTHWARD INTO OUR AREA...LIGHT SHOWERS WILL
INTERMITTENTLY DEVELOP THROUGHOUT THE AFTERNOON AND EVENING.
HI-RES AND REGIONAL MODELS ARE IN DISAGREEMENT ON HOW TO HANDLE
THE UPSTREAM CONVECTION TO OUR WEST LATER THIS EVENING. THE HRRR AND
NAM RE-INITIATES THUNDERSTORM DEVELOPMENT ALONG A LOW LEVEL
INSTABILITY GRADIENT OVER ILLINOIS DURING THE LATE AFTERNOON
AND BRINGS IT INTO OUR NORTHWESTERN ZONES BY MIDNIGHT. GIVEN
RADAR TRENDS OF DECAYING CONVECTION RIDING NORTHEAST ALONG WITH
ELEVATED INSTABILITY...IT APPEARS THAT THE HRRR AND NAM ARE A BIT
TOO FAR EASTWARD WITH THEIR SOLUTION. THE CMC REGIONAL APPEARS
MORE REALISTIC FOR TONIGHT BASED ON CONVECTIVE TRENDS. HAVE
THEREFORE FORECAST MORE IN LINE WITH THAT SOLUTION...BRINGING
MAINLY SCATTERED SHOWERS DUE TO ISENTROPIC LIFT GRADUALLY
NORTHWARD ACROSS AREA DURING THE EVENING HOURS.
SURFACE RIDGING TO OUR NORTH WILL SLIDE EASTWARD TONIGHT. THIS WILL
BRING RETURN FLOW TO OUR AREA...WITH A GRADUAL NORTHWARD SHIFT OF
OF AN ELEVATED INSTABILITY GRADIENT THAT HAS BEEN IN PLACE ACROSS
OUR SOUTH. THEREFORE...ANY REMNANT CONVECTIVE ACTIVITY TO OUR
WEST...IF REMAINING IN TACT EARLY TOMORROW MORNING...SHOULD TEND
TO FOCUS ACROSS OUR NORTHERN ZONES. WITH RETURN FLOW
DEVELOPING...AND MOSTLY CLOUDY SKIES FORECAST TONIGHT...OVERNIGHT
LOWS WILL BE SEVERAL DEGREES WARMER THAN THE PREVIOUS NIGHT.
MINIMUMS WILL RANGE FROM THE UPPER 40S NORTH...TO THE MID 50S
ACROSS THE SOUTH.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
WARM ADVECTION UNDER SOUTHERLY FLOW WILL CONTINUE INTO THE DAY
MONDAY. THIS WILL PLACE MUCH OF OUR AREA UNDER A WARM
SECTOR...WITH SOME CLEARING EXPECTED ACROSS THE SOUTH AND LIMITED
SHOWER ACTIVITY DURING THE DAYTIME HOURS. THIS WILL ALSO BRING
TEMPERATURES TO WELL ABOVE NORMAL VALUES...REACHING INTO THE 80S
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. ACROSS THE NORTH
THERE MAY REMAIN SUFFICIENT CLOUD COVER TO KEEP TEMPERATURES IN
THE LOW TO MIDDLE 70S...DEPENDING ON HOW FAR NORTH THE WARM FRONT
LIFTS DURING THE DAY.
A SHORTWAVE WILL EJECT NORTHEASTWARD OUT OF THE PLAINS AND ACROSS
THE NORTHERN GREAT LAKES MONDAY AFTERNOON. THIS WILL BRING
INCREASING SHEAR AND A WEAK SURFACE LOW ALONG THE WARM FRONT
TOWARD THE OHIO VALLEY DURING THE LATE AFTERNOON AND EVENING
HOURS. THIS WILL INITIATE CONVECTIVE DEVELOPMENT IN THE
DESTABILIZED WARM SECTOR DURING THE EVENING HOURS. THIS ACTIVITY
WILL SPREAD SOUTH AND EAST THROUGH OUR FORECAST AREA DURING THE
LATE EVENING INTO THE OVERNIGHT HOURS. THE ENVIRONMENT OF THIS
CONVECTION WILL BE SUPPORTIVE OF STORMS CAPABLE OF PRODUCING
DAMAGING STRAIGHT LINE WINDS AND POTENTIALLY LARGE HAIL.
AS THE CONVECTION PASSES THROUGH THE AREA MONDAY NIGHT...IT WILL
LAY OUT A LOW LEVEL CONVERGENT BOUNDARY ACROSS THE OHIO RIVER FOR
TUESDAY MORNING. THIS WILL THEN BE THE FOCUS OF ADDITIONAL
THUNDERSTORM DEVELOPMENT FOR TUESDAY AFTERNOON. ONGOING CHANCES
FOR PRECIPITATION WILL CONTINUE ACROSS THIS QUASI-STATIONARY
BOUNDARY INTO TUESDAY NIGHT IN OUR FORECAST AREA...AS WEAK
DISTURBANCES CONTINUE RIDE EASTWARD ALONG IT. A WARM AIRMASS WILL
BE IN PLACE BOTH TUESDAY AND TUESDAY NIGHT...WITH TEMPERATURES
EXPECTED TO BE WELL ABOVE SEASONAL NORMALS.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
SHORT WAVE ENERGY WILL BE PUSHING OFF TO THE EAST THROUGH THE DAY ON
WEDNESDAY AS MID AND UPPER LEVEL RIDGING BUILDS INTO THE REGION.
SOME SHOWERS AND THUNDERSTORMS MAY LINGER INTO THE MORNING
HOURS...BUT OVERALL EXPECT A DECREASING TREND FROM WEST TO EAST
ACROSS THE AREA THROUGH THE DAY. IN A WARM SOUTHWESTERLY LOW LEVEL
FLOW PATTERN...TEMPERATURES SHOULD CLIMB WELL ABOVE NORMAL BY
WEDNESDAY AFTERNOON. WILL GO WITH HIGHS GENERALLY IN THE MID
80S...PRETTY CLOSE TO WHAT IS SUGGESTED BY LOW LEVEL THICKNESSES.
SEVERAL SHORT WAVES WILL CONTINUE TO RIDE UP THE BACK SIDE OF THE
RIDGE THURSDAY INTO FRIDAY AND THIS WILL EVENTUALLY HELP TO FLATTEN
OUT THE RIDGE. THIS WILL ALSO ALLOW FOR A COLD FRONT TO SAG DOWN
FROM THE NORTH AND POSSIBLY LAY OUT ACROSS OUR AREA FRIDAY INTO
SATURDAY. THE RIDGE SHOULD BE STRONG ENOUGH TO KEEP THINGS DRY ON
THURSDAY...BUT AS THE RIDGE BEGINS TO BREAK DOWN...WILL ALLOW FOR A
CHANCE OF SHOWERS AND THUNDERSTORMS TO PUSH DOWN INTO OUR AREA
THURSDAY NIGHT INTO FRIDAY. HOW LONG THE PCPN THREAT LINGERS WILL
DEPEND ON EXACTLY HOW FAR SOUTH THE BOUNDARY IS ABLE TO PUSH. FOR
NOW WILL SLOWLY TAPER POPS OFF FROM THE NORTH HEADING INTO SATURDAY.
TEMPERATURES WILL ALSO BE DEPENDENT ON THE PLACEMENT AND TIMING OF
THE BOUNDARY. THURSDAY WILL BE ANOTHER WARM DAY WITH TEMPERATURES
WELL INTO THE 80S. AFTER THAT...WILL SLOWLY DECREASE TEMPS AS THE
UPPER LEVEL RIDGE BEGINS TO WEAKEN AND THE POSSIBILITY OF SOME PCPN
DEVELOPS.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
MI/UPR LEVEL RIDGE TO SLIDE EAST ACRS OHIO THIS EVENING KEEP THE
TAF SITES DRY EARLY. THE FLOW WILL BACK WITH THE PASSAGE OF THIS
RIDGE AXIS OVERNIGHT AND A SFC WARM FRONT LOCATED ACRS SRN MO AND
SRN KY WILL ADVANCE NORTH INTO THE OHIO VALLEY LATE. MARGINAL INSTBY
IS EXPECTED TO DEVELOP LATE TONIGHT AND WITH THE APPROACH OF THIS
FRONT CAN NOT RULE OUT SCTD THUNDERSTORMS. BEST FORCING WILL OCCUR
TO OUR NORTHWEST WHERE BEST LOW LEVEL JET WILL COME INTO PLAY.
HAVE CONTINUED VFR CONDITIONS OVERNIGHT AND LIMITED MENTION TO
VCTS AFTER 05Z. KDAY HAS THE BEST CHANCE OF OBSERVING THUNDER
OVERNIGHT.
EXPECT THE TAF SITES TO GET IN THE WARM SECTOR ON MONDAY WITH THE
WARM FRONT LIFTING NORTH AS SFC LOW TRACKS NE FROM THE MID MS VLY
INTO THE SRN GREAT LAKES BY MONDAY EVENING. EXPECT MODERATE INSTBY
TO DEVELOP WITH THE BEST THREAT FOR ORGANIZED THUNDERSTORMS WITH
THE APPROACH OF AN ASSOCIATED COLD FRONT MONDAY EVENING. HAVE
MENTIONED SHOWERS WITH VCTS AT KDAY/KILN AND KCMH/KLCK MID AFTN ON
AND VCTS AT KCVG/KLUK LATE IN THE AFTN AND THEN PREVAILING THUNDER
AT 30 HOUR KCVG MONDAY EVENING.
WINDS WILL SHIFT FROM EAST TO SOUTHWEST WITH ON MONDAY WITH SPEEDS
INCREASING AND GUSTS AS HIGH AS 24 KTS,
OUTLOOK...THUNDERSTORMS POSSIBLE AT TIMES FROM MONDAY NIGHT
THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...JGL
AVIATION...AR
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
315 PM EDT SAT APR 28 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL STALL OUT JUST SOUTH OF OUR AREA LATER
TONIGHT. AS AN AREA OF LOW PRESSURE DEVELOPS TO OUR WEST SUNDAY
NIGHT...THE FRONTAL BOUNDARY WILL LIFT BACK NORTH ACROSS OUR AREA
AS A WARM FRONT. THE LOW WILL THEN PUSH EASTWARD...BRINGING
SHOWERS AND THUNDERSTORMS TO THE AREA LATE MONDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
A TRICKY FORECAST FOR THE OVERNIGHT PERIOD AS A FRONTAL BOUNDARY
TO OUR SOUTH TRIES TO LIFT NORTHWARD TOWARD THE OHIO VALLEY. A
SHORTWAVE AND WEAK SURFACE LOW EJECTING EASTWARD OUT OF THE
PLAINS IS BEGINNING TO SHEAR OUT AS IT MOVES TOWARD THE OHIO
VALLEY. THIS IS TRIGGERING CONVECTIVE DEVELOPMENT ACROSS CENTRAL
MISSOURI AND ILLINOIS THIS AFTERNOON ALONG AN INSTABILITY
GRADIENT. THIS CONVECTION WILL SPREAD EASTWARD ALONG THE
INSTABILITY GRADIENT OVER THE NEXT SEVERAL HOURS.
LATEST RUC13 RUNS SHOWS THE NORTHERNMOST EXTENT OF THIS GRADIENT TO
PUSH NORTHWARD INTO OUR KENTUCKY COUNTIES AROUND 23Z. THIS IS ALSO
CONFIRMED BY SURFACE OBSERVATIONS...WITH TEMPS NEAR 75 IN
LOUISVILLE...AND ONLY THE UPPER 50S ACROSS OUR SOUTHERN ZONES.
TEMPERATURES ACROSS OUR SOUTH WILL LIKELY REACH THE 70S BY THE
EARLY EVENING AS THE BOUNDARY SHIFTS SLIGHTLY NORTHWARD...AND SOME
CLEARING MAKES IT INTO THE AREA. THEREFORE...IT APPEARS THE BEST
CHANCES FOR SURFACE BASED CONVECTION DURING THE EVENING WILL BE
ALONG AND SOUTH OF OUR SOUTHERNMOST COUNTIES. SOME ELEVATED
CONVECTION COULD OCCUR JUST NORTH OF THESE COUNTIES AS WELL AND
AS THE SURFACE LOW MOVES BY. HAVE THEREFORE FORECAST LIKELY POPS
IN THESE AREAS...WITH LOW END CHANCE POPS ELSEWHERE. DECENT SHEAR
PROFILES COULD COMBINE WITH CONVECTION ALONG THIS BOUNDARY TO
INDUCE POSSIBLE LARGE HAIL AND STRONG WINDS MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AFTER SUNSET...THE SEVERE THREAT WILL
DIMINISH AS WE LOSE INSOLATION AND SURFACE INSTABILITY DECREASES.
OVERALL ACTIVITY WILL DIMINISH BY MIDNIGHT...WITH SOME LINGERING
SHOWERS JUST NORTH OF THE SAGGING FRONTAL BOUNDARY. HAVE KEPT
CHANCE POPS ACROSS THE SOUTHERN ZONES DURING THE OVERNIGHT PERIOD.
ALTHOUGH CURRENT TEMPERATURES ACROSS THE NORTH ARE IN THE LOW 40S
WITH A FEW UPPER 30S...ABUNDANT CLOUD COVER SHOULD PREVENT
TEMPERATURES FROM FALLING INTO THE LOW 30S OVERNIGHT. A STRONG
TEMPERATURE GRADIENT WILL LIKELY REMAIN IN PLACE OVERNIGHT...WITH
UPPER 30S ACROSS THE NORTH...TO NEAR 50 ACROSS THE SOUTH.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
FRONTAL BOUNDARY WILL STALL OUT JUST SOUTH OF THE AREA SUNDAY
MORNING. AN ONGOING CHANCE FOR SHOWERS WILL OCCUR JUST NORTH OF
THIS BOUNDARY...ACROSS OUR SOUTHERN ZONES THROUGHOUT THE DAY.
ELSEWHERE...UNDER PARTLY TO MOSTLY CLOUDY SKIES...ENOUGH SUN
SHOULD MAKE IT THROUGH THE CLOUD COVER TO HELP TEMPERATURES RISE
INTO THE LOW 60S ACROSS THE AREA. CLOSER TO THE FRONTAL
BOUNDARY...ACROSS THE SOUTH...TEMPERATURES COULD REACH THE LOW
70S.
WEAK LOW PRESSURE APPROACHING FROM THE EAST WILL HELP PULL THE
FRONTAL BOUNDARY ACROSS THE OHIO VALLEY OVERNIGHT SUNDAY NIGHT.
THIS WILL BRING A CHANCE FOR SHOWERS AND THUNDERSTORMS MAINLY
ACROSS THE WEST DURING THE OVERNIGHT HOURS. THE LOW WILL THEN PUSH
NORTHEASTWARD ACROSS THE EASTERN GREAT LAKES MONDAY
NIGHT...PRODUCING ENOUGH CONVERGENCE TO PRODUCE SHOWERS AND
THUNDERSTORMS ACROSS MOST OF THE AREA. DURING THE DAY MONDAY OUR
AREA WILL BECOME WARM SECTORED. WITH RETURN FLOW IN PLACE...
TEMPERATURES WILL RISE INTO THE MID TO UPPER 70S AREA WIDE. A
FEW 80S CAN BE EXPECTED ACROSS OUR SOUTH AS WELL. MONDAY NIGHT
WILL ALSO BE A WARM ONE...WITH MID 50S TO UPPER 60S EXPECTED.
ONCE THE LOW PASSES...A WEAK BOUNDARY WILL LAY OUT ACROSS THE OHIO
RIVER MONDAY NIGHT. THIS WILL BECOME THE FOCUS FOR A CHANCE OF SHOWERS
AND THUNDERSTORMS ACROSS THESE ZONES INTO TUESDAY MORNING.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A MID LEVEL SHORT WAVE WILL LIFT NORTHEAST ACROSS THE REGION TUESDAY
THROUGH TUESDAY NIGHT AS RIDGING ALOFT TRIES TO BUILD INTO THE
EASTERN UNITED STATES. THIS WILL LEAD TO AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS THROUGH TUESDAY AFTERNOON...CONTINUING
INTO TUESDAY NIGHT. AS THE SHORT WAVE PUSHES OFF TO THE
EAST...EXPECT PCPN TO TAPER OFF LATE TUESDAY NIGHT INTO WEDNESDAY
MORNING. WITH RIDGING BUILDING ACROSS THE AREA AND BROAD
SOUTHWESTERLY FLOW...TEMPERATURES SHOULD REMAIN ABOVE NORMAL THROUGH
MID WEEK. HIGHS ON TUESDAY WILL BE IN THE MID TO UPPER 70S...WARMING
INTO THE LOWER 80S BY WEDNESDAY.
A COLD FRONT WILL PUSH DOWN FROM THE NORTHWEST THURSDAY INTO FRIDAY.
THIS WILL BRING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS. SOME
TIMING DIFFERENCES EXISTS BETWEEN THE MODELS...BUT IT APPEARS THE
BEST CHANCE FOR PCPN WOULD BE THURSDAY AFTERNOON INTO THURSDAY
NIGHT. COOLER AIR MOVING IN BEHIND THE FRONT WILL LEAD TO A RETURN
TO NEAR NORMAL TEMPERATURES HEADING INTO THE WEEKEND.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THUNDERSTORMS ASSOCIATED WITH A SHORT WAVE ALOFT HAVE GENERALLY MOVED
EAST OF TAF SITES. EXPECT THUNDERSTORMS TO PERSIST FOR A COUPLE
HOURS AT LUK NEAR A RESIDUAL BOUNDARY. MORE CONVECTION MAY DEVELOP
AT CVG LATER THIS AFTERNOON AS INSTABILITY RECOVERS AHEAD OF A
WARM FRONT. UPSTREAM OBSERVATIONS AND MODEL SOUNDINGS INDICATE
MVFR CEILINGS TONIGHT...IMPROVING TO VFR ON SUNDAY. WITH THE WARM
FRONT EXPECTED TO STAY SOUTH...WINDS WILL REMAIN OUT OF THE EAST
WITH SPEEDS AVERAGING 10 KNOTS.
OUTLOOK...THUNDERSTORMS ALONG WITH MVFR CEILINGS AND VISIBILITIES
ARE POSSIBLE AT TIMES FROM MONDAY NIGHT THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...LATTO
NEAR TERM...LATTO
SHORT TERM...LATTO
LONG TERM...JGL
AVIATION...CONIGLIO
AREA FORECAST DISCUSSION
NWS TULSA OK
1225 PM CDT SAT APR 28 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
WIDESPREAD CLOUDINESS WILL MAINTAIN LOW VFR TO PERIODIC MVFR
CEILINGS THROUGH MUCH OF THE FORECAST PERIOD. THE COLD FRONT
CURRENTLY JUST SOUTH OF KBVO MAY SLOWLY SAG A BIT FURTHER SOUTH
THIS EVENING...THOUGH CONFIDENCE REMAINS LOW IF AND/OR WHEN IT WILL
PASS THROUGH THE KTUL/KRVS SITES. WILL MAINTAIN OVERNIGHT AND
EARLY MORNING CONVECTIVE CHANCES FOR NE OK NEAR THE BOUNDARY.
&&
.PREV DISCUSSION... /ISSUED 1126 AM CDT SAT APR 28 2012/
..UPDATE...
DISCUSSION...
FRONTAL BOUNDARY CLEARING DEFINED WITHIN OKLAHOMA MESONET DATA
WHILE EXPANSIVE LOW CLOUDS HAVE LIMITED THE THERMAL GRADIENT
ACROSS THE FRONT THUS FAR. ANY MOVEMENT OF THE FRONT THROUGH THE
REMAINDER OF THE AFTERNOON IS EXPECTED TO BE MINIMAL...POSSIBLY
PUSHING A BIT FURTHER SOUTH IF THE LATEST RUC GUIDANCE IS
ACCURATE. OTHERWISE...THE WIDESPREAD CLOUDINESS WILL REMAIN IN
PLACE AND FOR AREAS SOUTH OF THE FRONT WHERE CLOUDS DO BREAK...A
QUICK WARM UP IS LIKELY. FORECAST SOUNDINGS ACROSS THE AREA
MAINTAIN A SUBSTANTIAL CAPPING INVERSION THROUGH THE AFTERNOON AND
THE UPDATED POPS WILL REALIGN THE SLIGHT CHANCES TO THE
IMMEDIATE VICINITY OF THE FRONT. OTHERWISE...MOST FORECAST
ELEMENTS ARE ON TRACK WITH MINOR ADJUSTMENTS ALONG THE CURRENT
FRONTAL ZONE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 65 78 65 80 / 50 50 70 50
FSM 65 84 64 81 / 20 20 30 50
MLC 64 79 66 80 / 20 20 30 30
BVO 61 77 63 79 / 60 60 70 50
FYV 60 80 61 77 / 40 20 40 60
BYV 62 80 61 77 / 30 30 40 60
MKO 63 80 64 79 / 40 30 50 40
MIO 64 79 64 80 / 50 50 70 50
F10 64 78 66 79 / 40 30 50 30
HHW 63 81 65 81 / 10 10 20 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
AVIATION...07
AREA FORECAST DISCUSSION
NWS TULSA OK
1126 AM CDT SAT APR 28 2012
...UPDATE...
.DISCUSSION...
FRONTAL BOUNDARY CLEARING DEFINED WITHIN OKLAHOMA MESONET DATA
WHILE EXPANSIVE LOW CLOUDS HAVE LIMITED THE THERMAL GRADIENT
ACROSS THE FRONT THUS FAR. ANY MOVEMENT OF THE FRONT THROUGH THE
REMAINDER OF THE AFTERNOON IS EXPECTED TO BE MINIMAL...POSSIBLY
PUSHING A BIT FURTHER SOUTH IF THE LATEST RUC GUIDANCE IS
ACCURATE. OTHERWISE...THE WIDESPREAD CLOUDINESS WILL REMAIN IN
PLACE AND FOR AREAS SOUTH OF THE FRONT WHERE CLOUDS DO BREAK...A
QUICK WARM UP IS LIKELY. FORECAST SOUNDINGS ACROSS THE AREA
MAINTAIN A SUBSTANTIAL CAPPING INVERSION THROUGH THE AFTERNOON AND
THE UPDATED POPS WILL REALIGN THE SLIGHT CHANCES TO THE
IMMEDIATE VICINITY OF THE FRONT. OTHERWISE...MOST FORECAST
ELEMENTS ARE ON TRACK WITH MINOR ADJUSTMENTS ALONG THE CURRENT
FRONTAL ZONE.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 77 65 79 65 / 20 70 50 70
FSM 83 64 84 64 / 10 30 30 30
MLC 80 65 80 66 / 10 50 20 40
BVO 72 61 79 63 / 20 70 60 80
FYV 77 62 80 62 / 10 40 40 40
BYV 78 62 80 62 / 10 40 40 50
MKO 80 64 81 64 / 10 50 40 50
MIO 76 63 78 63 / 20 60 60 70
F10 79 65 80 65 / 10 60 30 50
HHW 82 65 82 65 / 10 30 20 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
552 PM EDT SAT APR 28 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE EASTWARD LATE TODAY TODAY ALONG A
FRONTAL ZONE DRAPED FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHERN
MID-ATLANTIC COAST. THIS WILL CREATE A FEW PERIODS OF LIGHT RAIN FOR
MUCH OF CENTRAL PA THROUGH EARLY TONIGHT. A LARGE AREA OF HIGH
PRESSURE WILL NOSE SOUTHEAST FROM THE GREAT LAKES TONIGHT AND
SUNDAY...PROVIDING FAIR WEATHER AND MODERATING TEMPERATURES FOR
SUNDAY AND MONDAY. WARMER WEATHER IS EXPECTED FOR MUCH OF THE
UPCOMING WORK WEEK AS AN UPPER RIDGE BECOMES ANCHORED OVER THE
SOUTHEAST STATES AND WESTERN ATLANTIC. AT THE SAME TIME...THE
PATTERN SHOULD BECOME MORE UNSETTLED WITH SEVERAL OPPORTUNITIES FOR
CONVECTIVE RAINFALL...ESPECIALLY DURING THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SHIELD OF OVC ALTOCU/ALTO STRATUS /CENTRAL AND WEST/...AND
CIRROSTRATUS /EAST/...WILL LOWER AND THICKEN UP THROUGH THE EARLY
EVENING AS AN AREA OF LIGHT PRECIP RACES IN FROM NERN OHIO AND SWRN
PENN. RECENT REPORT VIA ONE OF OUR LONG-TIME NWS EMPLOYEES RESIDING
IN ALTOONA NOTED SOME SNOW PELLETS MIXING IN WITH THE LIGHT RAIN
BEGINNING THERE OVER THE PAST HOUR.
17Z RUC CONFIRMS AN APPROX 30NM WIDE CHANNEL OF NEAR 0C WET BULB
TEMPS IN THE 900-950 MB LAYER /WITH SUB-FREEZING WET BULBS ALOFT/
CAPABLE OF MAINTAINING SOME WET SNOW/PELLETS ALL THE WAY TO THE
GROUND. PAINTED THIS SPECKLING OF LIGHT WEST SNOW IN OUR WEATHER
GRIDS INTO THE EARLY EVENING HOURS ACROSS WEST-CENTRAL AND CENTRAL
PENN /BUT MAINLY AT ELEVATIONS AOA 2000 FT MSL/. NO ACCUMS WILL BE
POSSIBLE BASED ON SFC TEMPS AND GENERALLY VERY LIGHT PRECIP RATES.
TEMPS ARE BASICALLY AT THEIR MAXES IN MOST PLACES...AND WILL EVEN
FALL SEVERAL DEG F ACROSS THE CENTRAL AND WESTERN ZONES AS THE
PRECIP SHIELD SPREADS INTO THE VERY DRY LLVL AIR RESIDING HERE
HIGHLIGHTED BY SFC DEWPOINTS IN THE MID TEENS TO LOWER 20S.
WILL MAINTAIN THE HIGH POPS /AROUND 90 PERCENT/ ACROSS THE CENTRAL
AND SOUTHERN ZONES...BUT EMPHASIZE THAT QPF FOR THIS ENTIRE EVENT
WILL BE AOB ONE TENTH OF AN INCH BASED ON SHORT TERM MODEL GUIDANCE
AND HOURLY PRECIP VIA UPSTREAM OBS. A FEW SPOTS ACRS THE SRN TIER OF
PENN COULD APPROACH 0.20 OF AN INCH FOR RAINFALL OVER THE UPCOMING
12 HOURS OR SO.
EXPECT THE GREATEST AREAL COVERAGE OF THE PRECIP TO OCCUR ACROSS
THE CWA BETWEEN 22-02Z. DECREASING POPS WILL DEVELOP FROM FROM
NW-SE AFTER THE LOW/SFC WAVE PUSHES TO THE EAST. THE END TO THE
RAIN SHOULD BE AROUND OR JUST AFTER MIDNIGHT.
CLEARING LINE PRESSES STEADILY TO THE SE LATER TONIGHT THROUGH THE
PREDAWN HOURS OF SUNDAY.
TRANSITIONED FROM THE FREEZE WATCH TO A HARD FREEZE WARNING UP
NORTH...AND A FREEZE WARNING ACROSS THE REGION NEAR...AND TO THE
SOUTH OF INTERSTATE 80. THIS BLENDS WELL WITH SIMILAR PRODUCTS
ISSUED BY ADJACENT WFOS. MINS WILL RANGE FROM THE LOWER 20S ACROSS
THE NRN TIER...TO THE MID 30S ALONG THE MASON/DIXON LINE. TEMPS
COULD EASILY DIP INTO THE UPPER TEENS IN SOME OF THE NORMALLY COLD
RURAL VALLEYS UP NORTH BASED ON CURRENT AND UPSTREAM SFC DEWPOINTS.
AMPLE CLOUD COVER ACROSS SOUTHERN PENN UNTIL VERY EARLY SUNDAY
SHOULD PREVENT TEMPS FROM REACHING THE FREEZING MARK FOR AN
OVERNIGHT LOW...RATHER SETTLE BETWEEN 33-35F IN MOST LOCATIONS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
SUNNY SKIES WILL OCCUR IN ALL AREAS SUNDAY THANKS TO A STRONG
/1029MB/ AREA OF HIGH PRESSURE NOSING SE FROM THE GREAT LAKES. THE
VERY DRY LOW TO MID LEVEL AIR WILL MAKE IT TOUGH TO MAKE ANY CLOUDS
REACH THE CWA DESPITE A NNW FETCH OFF THE LOWER LAKES.
THE FRONTAL BOUNDARY DOES NOT MIGRATE TOO FAR TO THE SOUTH...AND MAY
BUBBLE UP TO THE NORTH AS A WARM FRONT WHICH COULD ENTER FAR SWRN
PA. A FEW BRIEF -SHRA COULD SNEAK TWD SOMERSET COUNTY LATE IN THE
DAY...BUT CONSIDERING THE DEPTH OF THE DRY AIR RESIDING OVER THE
LOCAL AREA...POPS WILL BE BASICALLY NIL THROUGH ALL OF SUNDAY.
HIGHS ON SUNDAY WILL CLIMB TO 8-13F HIGHER THAN TODAY...BUT WILL
STILL BE A LITTLE BELOW NORMAL - WHICH ARE NOW IN THE 60S - EVEN IN
THE NRN MTS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
A RIDGE BUILDING OVER THE REGION SUNDAY NIGHT WILL PROPAGATE
EASTWARD AS THE UPPER LEVEL LOW CONTINUES TO MOVE NORTHWARD. THIS
RIDGE WILL ALLOW FOR CLEARING SKIES SUNDAY NIGHT AND WARMER
TEMPERATURES...WITH 12C AT 850MB MONDAY AFTERNOON. THE WARMING
TREND WILL CONTINUE THROUGH MID WEEK DUE TO WARM SOUTHERLY FLOW.
THE RIDGE WILL FLATTEN AS A WEAK TROUGH MOVING THROUGH CENTRAL
CANADA LATE MONDAY...EARLY TUESDAY...COUPLING THE INSTABILITY WITH
MOIST FLOW SHOULD ALLOW FOR A TIME OF MCS-FAVORABLE CONDITIONS.
THIS SHOULD ALLOW FOR SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS
MONDAY EVENING...AND CONTINUING THROUGH TUESDAY MORNING. HAVE
INCREASED POPS ACCORDINGLY AND CURRENT MODEL EASTWARD PROGRESSION.
THE ZONAL FLOW THROUGH THE MIDDLE OF THE WEEK WILL ALLOW FOR ANY
SHORT WAVE RIPPLING THROUGH THE PATTERN TO BRING A CHANCE FOR
SHOWERS....MAINLY IN THE AFTERNOON. A DECENT GRADIENT THURSDAY MAY
ALLOW FOR GUSTIER WINDS. THE MODELS ARE IN AGREEMENT THROUGH
THURSDAY AS THE EC AND THE GFS BEGIN TO DIVERGE FRIDAY. THE EC
SPEEDS UP THE THE PROGRESSION OF THE UPPER LEVEL LOWS THROUGH THE
CENTRAL CONUS FRIDAY MORNING. THIS THEN ALLOWS THE TWO MODELS TO
BECOME OUT OF PHASE. BOTH MODELS KEEPS WARM AIR THROUGH THE AREA
THROUGH THE END OF THE WEEK...WITH COOLER TEMPS ADVECTING IN NEXT
WEEKEND. HAVE KEPT 30 POPS OVER MUCH OF THE REGION...ESPECIALLY
THE ELEVATED AREAS...THURSDAY AND FRIDAY. CURRENTLY THERE IS A LOW
PROBABILITY FOR ANY PRECIP NEXT WEEKEND.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
A SHIELD OF MAINLY MID AND HIGH CLOUDS WILL CONTINUE TO STREAM EAST
ACROSS THE REGION THROUGH AT LEAST THE FIRST HALF OF TONIGHT...BUT
VFR CONDS WILL PREVAIL AT MOST AIRFIELDS...EVEN DURING SOME
INTERMITTENT VERY LIGHT RAIN. A FEW SNOW PELLETS COULD BE MIXED IN
NEAR KJST AND EAST THROUGH KAOO WHERE TEMPS AOA 1500 AGL ARE NEAR TO
JUST BELOW ZERO C.
LOW PRES RIDING EWD FM THE MID MS VLY THRU THE MID-SOUTH WILL SPREAD
LOWER CIGS ACROSS CENTRAL AND SRN PA AIRFIELDS WITH LIGHT RAIN
LIKELY SOUTH OF DUJ-IPT LINE LATE THIS AFTN THROUGH THIS EVENING.
KIPT WILL BE ON THE NRN EDGE OF VERY LIGHT PRECIP THIS EVENING.
HOWEVER...THE LATEST BLEND OF THE 21Z RUC AND 18Z NAM QPF INDICATES
THAT ANY MEASURABLE RAINFL WILL BE SOUTH OF INTERSTATE 80.
BORDERLINE MVFR CIGS ARE LIKELY OVR JST DURING THE FIRST PART OF THE
OVERNIGHT...BEFORE A DRYING NLY FLOW BRINGS IMPROVING CONDS AND
CLEARING SKIES BY DAYBREAK SUNDAY.
OUTLOOK...
SUN...VFR/NO SIG WX EXPECTED.
MON-THU...MAINLY VFR WITH SCT TSTM IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 2 AM TO 9 AM EDT SUNDAY FOR PAZ004>006-
010>012-037-041-042.
FREEZE WARNING FROM 3 AM TO 9 AM EDT SUNDAY FOR PAZ017>019-
024>028-045-046-049>053-058.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
353 PM EDT SAT APR 28 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE EASTWARD LATE TODAY TODAY ALONG A
FRONTAL ZONE DRAPED FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHERN
MID-ATLANTIC COAST. THIS WILL CREATE A FEW PERIODS OF LIGHT RAIN FOR
MUCH OF CENTRAL PA THROUGH EARLY TONIGHT. A LARGE AREA OF HIGH
PRESSURE WILL NOSE SOUTHEAST FROM THE GREAT LAKES TONIGHT AND
SUNDAY...PROVIDING FAIR WEATHER AND MODERATING TEMPERATURES FOR
SUNDAY AND MONDAY. WARMER WEATHER IS EXPECTED FOR MUCH OF THE
UPCOMING WORK WEEK AS AN UPPER RIDGE BECOMES ANCHORED OVER THE
SOUTHEAST STATES AND WESTERN ATLANTIC. AT THE SAME TIME...THE
PATTERN SHOULD BECOME MORE UNSETTLED WITH SEVERAL OPPORTUNITIES FOR
CONVECTIVE RAINFALL...ESPECIALLY DURING THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
SHIELD OF OVC ALTOCU/ALTO STRATUS /CENTRAL AND WEST/...AND
CIRROSTRATUS /EAST/...WILL LOWER AND THICKEN UP THROUGH THE EARLY
EVENING AS AN AREA OF LIGHT PRECIP RACES IN FROM NERN OHIO AND SWRN
PENN. RECENT REPORT VIA ONE OF OUR LONG-TIME NWS EMPLOYEES RESIDING
IN ALTOONA NOTED SOME SNOW PELLETS MIXING IN WITH THE LIGHT RAIN
BEGINNING THERE OVER THE PAST HOUR.
17Z RUC CONFIRMS AN APPROX 30NM WIDE CHANNEL OF NEAR 0C WET BULB
TEMPS IN THE 900-950 MB LAYER /WITH SUB-FREEZING WET BULBS ALOFT/
CAPABLE OF MAINTAINING SOME WET SNOW/PELLETS ALL THE WAY TO THE
GROUND. PAINTED THIS SPECKLING OF LIGHT WEST SNOW IN OUR WEATHER
GRIDS INTO THE EARLY EVENING HOURS ACROSS WEST-CENTRAL AND CENTRAL
PENN /BUT MAINLY AT ELEVATIONS AOA 2000 FT MSL/. NO ACCUMS WILL BE
POSSIBLE BASED ON SFC TEMPS AND GENERALLY VERY LIGHT PRECIP RATES.
TEMPS ARE BASICALLY AT THEIR MAXES IN MOST PLACES...AND WILL EVEN
FALL SEVERAL DEG F ACROSS THE CENTRAL AND WESTERN ZONES AS THE
PRECIP SHIELD SPREADS INTO THE VERY DRY LLVL AIR RESIDING HERE
HIGHLIGHTED BY SFC DEWPOINTS IN THE MID TEENS TO LOWER 20S.
WILL MAINTAIN THE HIGH POPS /AROUND 90 PERCENT/ ACROSS THE CENTRAL
AND SOUTHERN ZONES...BUT EMPHASIZE THAT QPF FOR THIS ENTIRE EVENT
WILL BE AOB ONE TENTH OF AN INCH BASED ON SHORT TERM MODEL GUIDANCE
AND HOURLY PRECIP VIA UPSTREAM OBS. A FEW SPOTS ACRS THE SRN TIER OF
PENN COULD APPROACH 0.20 OF AN INCH FOR RAINFALL OVER THE UPCOMING
12 HOURS OR SO.
EXPECT THE GREATEST AREAL COVERAGE OF THE PRECIP TO OCCUR ACROSS
THE CWA BETWEEN 22-02Z. DECREASING POPS WILL DEVELOP FROM FROM
NW-SE AFTER THE LOW/SFC WAVE PUSHES TO THE EAST. THE END TO THE
RAIN SHOULD BE AROUND OR JUST AFTER MIDNIGHT.
CLEARING LINE PRESSES STEADILY TO THE SE LATER TONIGHT THROUGH THE
PREDAWN HOURS OF SUNDAY.
TRANSITIONED FROM THE FREEZE WATCH TO A HARD FREEZE WARNING UP
NORTH...AND A FREEZE WARNING ACROSS THE REGION NEAR...AND TO THE
SOUTH OF INTERSTATE 80. THIS BLENDS WELL WITH SIMILAR PRODUCTS
ISSUED BY ADJACENT WFOS. MINS WILL RANGE FROM THE LOWER 20S ACROSS
THE NRN TIER...TO THE MID 30S ALONG THE MASON/DIXON LINE. TEMPS
COULD EASILY DIP INTO THE UPPER TEENS IN SOME OF THE NORMALLY COLD
RURAL VALLEYS UP NORTH BASED ON CURRENT AND UPSTREAM SFC DEWPOINTS.
AMPLE CLOUD COVER ACROSS SOUTHERN PENN UNTIL VERY EARLY SUNDAY
SHOULD PREVENT TEMPS FROM REACHING THE FREEZING MARK FOR AN
OVERNIGHT LOW...RATHER SETTLE BETWEEN 33-35F IN MOST LOCATIONS.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
SUNNY SKIES WILL OCCUR IN ALL AREAS SUNDAY THANKS TO A STRONG
/1029MB/ AREA OF HIGH PRESSURE NOSING SE FROM THE GREAT LAKES. THE
VERY DRY LOW TO MID LEVEL AIR WILL MAKE IT TOUGH TO MAKE ANY CLOUDS
REACH THE CWA DESPITE A NNW FETCH OFF THE LOWER LAKES.
THE FRONTAL BOUNDARY DOES NOT MIGRATE TOO FAR TO THE SOUTH...AND MAY
BUBBLE UP TO THE NORTH AS A WARM FRONT WHICH COULD ENTER FAR SWRN
PA. A FEW BRIEF -SHRA COULD SNEAK TWD SOMERSET COUNTY LATE IN THE
DAY...BUT CONSIDERING THE DEPTH OF THE DRY AIR RESIDING OVER THE
LOCAL AREA...POPS WILL BE BASICALLY NIL THROUGH ALL OF SUNDAY.
HIGHS ON SUNDAY WILL CLIMB TO 8-13F HIGHER THAN TODAY...BUT WILL
STILL BE A LITTLE BELOW NORMAL - WHICH ARE NOW IN THE 60S - EVEN IN
THE NRN MTS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
A RIDGE BUILDING OVER THE REGION SUNDAY NIGHT WILL PROPAGATE
EASTWARD AS THE UPPER LEVEL LOW CONTINUES TO MOVE NORTHWARD. THIS
RIDGE WILL ALLOW FOR CLEARING SKIES SUNDAY NIGHT AND WARMER
TEMPERATURES...WITH 12C AT 850MB MONDAY AFTERNOON. THE WARMING
TREND WILL CONTINUE THROUGH MID WEEK DUE TO WARM SOUTHERLY FLOW.
THE RIDGE WILL FLATTEN AS A WEAK TROUGH MOVING THROUGH CENTRAL
CANADA LATE MONDAY...EARLY TUESDAY...COUPLING THE INSTABILITY WITH
MOIST FLOW SHOULD ALLOW FOR A TIME OF MCS-FAVORABLE CONDITIONS.
THIS SHOULD ALLOW FOR SHOWERS AND POSSIBLY ISOLATED THUNDERSTORMS
MONDAY EVENING...AND CONTINUING THROUGH TUESDAY MORNING. HAVE
INCREASED POPS ACCORDINGLY AND CURRENT MODEL EASTWARD PROGRESSION.
THE ZONAL FLOW THROUGH THE MIDDLE OF THE WEEK WILL ALLOW FOR ANY
SHORT WAVE RIPPLING THROUGH THE PATTERN TO BRING A CHANCE FOR
SHOWERS....MAINLY IN THE AFTERNOON. A DECENT GRADIENT THURSDAY MAY
ALLOW FOR GUSTIER WINDS. THE MODELS ARE IN AGREEMENT THROUGH
THURSDAY AS THE EC AND THE GFS BEGIN TO DIVERGE FRIDAY. THE EC
SPEEDS UP THE THE PROGRESSION OF THE UPPER LEVEL LOWS THROUGH THE
CENTRAL CONUS FRIDAY MORNING. THIS THEN ALLOWS THE TWO MODELS TO
BECOME OUT OF PHASE. BOTH MODELS KEEPS WARM AIR THROUGH THE AREA
THROUGH THE END OF THE WEEK...WITH COOLER TEMPS ADVECTING IN NEXT
WEEKEND. HAVE KEPT 30 POPS OVER MUCH OF THE REGION...ESPECIALLY
THE ELEVATED AREAS...THURSDAY AND FRIDAY. CURRENTLY THERE IS A LOW
PROBABILITY FOR ANY PRECIP NEXT WEEKEND.
&&
.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
THICKENING MID AND HIGH CLOUDS WILL CONTINUE OVERSPREAD THE REGION
THIS AFTERNOON AND EVENING BUT VFR CONDS WILL PREVAIL...EVEN DURING
SOME PERIODS OF LIGHT RAIN. SOME WET SNOWFLAKES/PELLETS COULD BE
MIXED IN FROM KDUJ AND KFIG...ESE THROUGH KUNV AND KAOO WHERE TEMPS
AOA 1500 AGL ARE NEAR TO JUST BELOW ZERO C.
LOW PRES RIDING EWD FM THE MID MS VLY THRU THE MID-SOUTH WILL SPREAD
LOWER CIGS ACROSS CENTRAL AND SRN PA AIRFIELDS WITH LIGHT RAIN
LIKELY SOUTH OF DUJ-IPT LINE LATE THIS AFTN THROUGH THIS EVENING.
KIPT WILL BE ON THE NRN EDGE OF PRECIP THIS EVENING...BUT LATEST
BLEND OF THE 09Z SREF...12Z NAM AND 17Z RUC QPF INDICATES THAT SOME
VERY LIGHT AMTS OF RAIN ARE POSSIBLE THERE LATE TODAY AND EARLY TNGT.
MVFR CIGS APPEAR LIKELY OVR AT AOO/JST FM LATE THIS EVENING INTO THE
FIRST PART OF TNT...BEFORE A DRYING NLY FLOW BRINGS IMPROVING CONDS
AND CLEARING SKIES BY DAYBREAK SUNDAY.
OUTLOOK...
SUN...VFR/NO SIG WX EXPECTED.
MON-THU...MAINLY VFR WITH SCT TSTM IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
FREEZE WARNING FROM 2 AM TO 9 AM EDT SUNDAY FOR PAZ004>006-
010>012-037-041-042.
FREEZE WARNING FROM 3 AM TO 9 AM EDT SUNDAY FOR PAZ017>019-
024>028-045-046-049>053-058.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...CERU/GARTNER
AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
256 PM EDT SAT APR 28 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE WILL RIDE EASTWARD LATE TODAY TODAY ALONG A
FRONTAL ZONE DRAPED FROM THE MID MISSISSIPPI VALLEY TO THE SOUTHERN
MID-ATLANTIC COAST. THIS WILL CREATE A FEW PERIODS OF LIGHT RAIN FOR
MUCH OF CENTRAL PA THROUGH EARLY TONIGHT. A LARGE AREA OF HIGH
PRESSURE WILL NOSE SOUTHEAST FROM THE GREAT LAKES TONIGHT AND
SUNDAY...PROVIDING FAIR WEATHER AND MODERATING TEMPERATURES FOR
SUNDAY AND MONDAY. WARMER WEATHER IS EXPECTED FOR MUCH OF THE
UPCOMING WORK WEEK AS AN UPPER RIDGE BECOMES ANCHORED OVER THE
SOUTHEAST STATES AND WESTERN ATLANTIC. AT THE SAME TIME...THE
PATTERN SHOULD BECOME MORE UNSETTLED WITH SEVERAL OPPORTUNITIES FOR
CONVECTIVE RAINFALL...ESPECIALLY DURING THE MIDDLE OF THE WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
SHIELD OF OVC ALTOCU/ALTO STRATUS /CENTRAL AND WEST/...AND
CIRROSTRATUS /EAST/...WILL LOWER AND THICKEN UP THROUGH THE EARLY
EVENING AS AN AREA OF LIGHT PRECIP RACES IN FROM NERN OHIO AND SWRN
PENN. RECENT REPORT VIA ONE OF OUR LONG-TIME NWS EMPLOYEES RESIDING
IN ALTOONA NOTED SOME SNOW PELLETS MIXING IN WITH THE LIGHT RAIN
BEGINNING THERE OVER THE PAST HOUR.
17Z RUC CONFIRMS AN APPROX 30NM WIDE CHANNEL OF NEAR 0C WET BULB
TEMPS IN THE 900-950 MB LAYER /WITH SUB-FREEZING WET BULBS ALOFT/
CAPABLE OF MAINTAINING SOME WET SNOW/PELLETS ALL THE WAY TO THE
GROUND. PAINTED THIS SPECKLING OF LIGHT WEST SNOW IN OUR WEATHER
GRIDS INTO THE EARLY EVENING HOURS ACROSS WEST-CENTRAL AND CENTRAL
PENN /BUT MAINLY AT ELEVATIONS AOA 2000 FT MSL/. NO ACCUMS WILL BE
POSSIBLE BASED ON SFC TEMPS AND GENERALLY VERY LIGHT PRECIP RATES.
TEMPS ARE BASICALLY AT THEIR MAXES IN MOST PLACES...AND WILL EVEN
FALL SEVERAL DEG F ACROSS THE CENTRAL AND WESTERN ZONES AS THE
PRECIP SHIELD SPREADS INTO THE VERY DRY LLVL AIR RESIDING HERE
HIGHLIGHTED BY SFC DEWPOINTS IN THE MID TEENS TO LOWER 20S.
WILL MAINTAIN THE HIGH POPS /AROUND 90 PERCENT/ ACROSS THE CENTRAL
AND SOUTHERN ZONES...BUT EMPHASIZE THAT QPF FOR THIS ENTIRE EVENT
WILL BE AOB ONE TENTH OF AN INCH BASED ON SHORT TERM MODEL GUIDANCE
AND HOURLY PRECIP VIA UPSTREAM OBS. A FEW SPOTS ACRS THE SRN TIER OF
PENN COULD APPROACH 0.20 OF AN INCH FOR RAINFALL OVER THE UPCOMING
12 HOURS OR SO.
EXPECT THE GREATEST AREAL COVERAGE OF THE PRECIP TO OCCUR ACROSS
THE CWA BETWEEN 22-02Z. DECREASING POPS WILL DEVELOP FROM FROM
NW-SE AFTER THE LOW/SFC WAVE PUSHES TO THE EAST. THE END TO THE
RAIN SHOULD BE AROUND OR JUST AFTER MIDNIGHT.
CLEARING LINE PRESSES STEADILY TO THE SE LATER TONIGHT THROUGH THE
PREDAWN HOURS OF SUNDAY.
TRANSITIONED FROM THE FREEZE WATCH TO A HARD FREEZE WARNING UP
NORTH...AND A FREEZE WARNING ACROSS THE REGION NEAR...AND TO THE
SOUTH OF INTERSTATE 80. THIS BLENDS WELL WITH SIMILAR PRODUCTS
ISSUED BY ADJACENT WFOS. MINS WILL RANGE FROM THE LOWER 20S ACROSS
THE NRN TIER...TO THE MID 30S ALONG THE MASON/DIXON LINE. TEMPS
COULD EASILY DIP INTO THE UPPER TEENS IN SOME OF THE NORMALLY COLD
RURAL VALLEYS UP NORTH BASED ON CURRENT AND UPSTREAM SFC DEWPOINTS.
AMPLE CLOUD COVER ACROSS SOUTHERN PENN UNTIL VERY EARLY SUNDAY
SHOULD PREVENT TEMPS FROM REACHING THE FREEZING MARK FOR AN
OVERNIGHT LOW...RATHER SETTLE BETWEEN 33-35F IN MOST LOCATIONS.
&&
.SHORT TERM /SUNDAY/...
SUNNY SKIES WILL OCCUR IN ALL AREAS SUNDAY THANKS TO A STRONG
/1029MB/ AREA OF HIGH PRESSURE NOSING SE FROM THE GREAT LAKES. THE
VERY DRY LOW TO MID LEVEL AIR WILL MAKE IT TOUGH TO MAKE ANY CLOUDS
REACH THE CWA DESPITE A NNW FETCH OFF THE LOWER LAKES.
THE FRONTAL BOUNDARY DOES NOT MIGRATE TOO FAR TO THE SOUTH...AND MAY
BUBBLE UP TO THE NORTH AS A WARM FRONT WHICH COULD ENTER FAR SWRN
PA. A FEW BRIEF -SHRA COULD SNEAK TWD SOMERSET COUNTY LATE IN THE
DAY...BUT CONSIDERING THE DEPTH OF THE DRY AIR RESIDING OVER THE
LOCAL AREA...POPS WILL BE BASICALLY NIL THROUGH ALL OF SUNDAY.
HIGHS ON SUNDAY WILL CLIMB TO 8-13F HIGHER THAN TODAY...BUT WILL
STILL BE A LITTLE BELOW NORMAL - WHICH ARE NOW IN THE 60S - EVEN IN
THE NRN MTS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
THE ONLY FORECAST TROUBLE WILL BE SUNDAY NIGHT AS
NEARLY IDEAL RADIATIONAL COOLING WILL AGAIN PROVIDE THE LIKELIHOOD
OF A FREEZE OVER MUCH IF NOT ALL OF THE AREA. WILL HOLD OFF ON ANY
FURTHER FLAGS AT THIS POINT...BUT MONDAY AM LOOKS A DEG OR TWO
COLDER THAN SUN AM.
GENERALLY PROGRESSIVE WEST TO SWRLY UPPER FLOW IS EXPECTED THROUGH
THE LONG TERM PERIOD. THIS WILL BRING SEVERAL FRONTS AND CHANCES
FOR...MAINLY LIGHT...PCPN TO CENTRAL PA.
GRADUAL WARMING TREND CONTINUES MONDAY. HIGHS THROUGH NEXT WEEK
INCREASE ABOUT 5F EACH DAY IN RETURN FLOW ON BACK OF HIGH. TEMPS
WILL TOP OUT IN THE 70S FOR THE SECOND HALF OF THE WEEK...WITH
80S EVEN POSSIBLE IN SPOTS. INDIVIDUAL SHORTWAVES...WHICH ARE
VERY HARD TO RESOLVE AT THESE RANGES...WILL MODULATE OPPORTUNITIES
OF PCPN. THE NEXT HIGH CHC OF PRECIP WILL BE DURING A TIME OF MCS-
FAVORABLE CONDITIONS MONDAY NIGHT. WILL GO WITH POPS INCREASING TO
50 PCT IN THE WEST FOR MONDAY NIGHT...AND 40S FOR TUESDAY. THEN
PERPETUAL 30 POPS WILL BE CARRIED ON THRU FRIDAY.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THICKENING MID AND HIGH CLOUDS WILL CONTINUE OVERSPREAD THE REGION
THIS AFTERNOON AND EVENING BUT VFR CONDS WILL PREVAIL...EVEN DURING
SOME PERIODS OF LIGHT RAIN. SOME WET SNOWFLAKES/PELLETS COULD BE
MIXED IN FROM KDUJ AND KFIG...ESE THROUGH KUNV AND KAOO WHERE TEMPS
AOA 1500 AGL ARE NEAR TO JUST BELOW ZERO C.
LOW PRES RIDING EWD FM THE MID MS VLY THRU THE MID-SOUTH WILL SPREAD
LOWER CIGS ACROSS CENTRAL AND SRN PA AIRFIELDS WITH LIGHT RAIN
LIKELY SOUTH OF DUJ-IPT LINE LATE THIS AFTN THROUGH THIS EVENING.
KIPT WILL BE ON THE NRN EDGE OF PRECIP THIS EVENING...BUT LATEST
BLEND OF THE 09Z SREF...12Z NAM AND 17Z RUC QPF INDICATES THAT SOME
VERY LIGHT AMTS OF RAIN ARE POSSIBLE THERE LATE TODAY AND EARLY TNGT.
MVFR CIGS APPEAR LIKELY OVR AT AOO/JST FM LATE THIS EVENING INTO THE
FIRST PART OF TNT...BEFORE A DRYING NLY FLOW BRINGS IMPROVING CONDS
AND CLEARING SKIES BY DAYBREAK SUNDAY.
OUTLOOK...
SUN...VFR/NO SIG WX EXPECTED.
MON-THU...MAINLY VFR WITH SCT TSTM IMPACTS POSSIBLE.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
HARD FREEZE WARNING FROM 2 AM TO 9 AM EDT SUNDAY FOR
PAZ004>006-010>012-037-041-042.
FREEZE WARNING FROM 3 AM TO 9 AM EDT SUNDAY FOR PAZ017>019-
024>028-045-046-049>053-058.
&&
$$
SYNOPSIS...LAMBERT
NEAR TERM...LAMBERT
SHORT TERM...LAMBERT
LONG TERM...GARTNER/STEINBUGL
AVIATION...LAMBERT/STEINBUGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1026 PM EDT SUN APR 29 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL REMAIN OVER THE NORTHWEST PIEDMONT AND
NORTHERN FOOTHILLS OF NORTH CAROLINA TODAY...BEFORE LIFTING NORTH AS
A WARM FRONT ON MONDAY. HIGH PRESSURE WILL THEN MOVE OVER THE AREA
AND DOMINATE THE WEATHER THROUGH THE REST OF THE WEEK. THE NEXT COLD
FRONT IS EXPECTED TO MOVE INTO THE AREA JUST IN TIME FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 1030 PM...MID AND HIGH LEVEL CLOUDS HAVE STARTED TO SPREAD
OVER THE WESTERN ZONES...AND CLOUD COVER HAS BEEN INCREASED IN THESE
AREAS IN THE GRIDS. LOW CLOUDS ARE BEGINNING TO SPREAD INLAND FROM
THE SOUTH COAST OF NORTH CAROLINA. THE LOW CLOUDS SHOULD CONTINUE TO
EXPEND WESTWARD THE REST OF THE NIGHT...AFFECTING THE I-77 AND I-40
CORRIDORS ACROSS THE FOOTHILLS AND PIEDMONT LATE TONIGHT. I TRIMMED
POPS BACK A LITTLE INTO MONDAY MORNING...MAINLY TO ACCOUNT FOR
DIURNAL TRENDS.
AS OF 755 PM...CU FIELD IS HANGING ON ACROSS THE BLUE RIDGE...WITH A
LITTLE MORE HIGH CLOUD COVER OVERSPREADING THE REGION. STILL NOT
EXPECTING ANY CONVECTION TO DEVELOP OUT OF THE MTN CLOUDS AS CIN
VALUES ARE BEGINNING TO INCREASE ACROSS THE REGION. THE REST OF THE
FORECAST LOOKS GOOD.
AS OF 500 PM...TEMPS ARE A LITTLE COOLER THAN PREDICTED OVER THE
REGION THIS AFTN...MAINLY OVER THE UPSTATE AND NE GA. MAXES HAVE
BEEN UPDATED TO REFLECT THIS TREND. PERSISTENT...UPSLOPE INDUCED CU
CONTINUES ACROSS THE BLUE RIDGE. THE CU MAY LAST A WAYS PAST SUNSET
IN THESE AREAS...AIDED BY THE UPSLOPE.
PREVIOUS DISCUSSION...
AS OF 145 PM...UPPER RIDGE CONTINUES TO BUILD OVER THE SOUTHEAST
STATES TODAY...WITH AXIS STILL JUST TO THE WEST OF THE CWFA. CLOUDS
ON VIS LOOK SUPPRESSED UNDER THE RIDGE...AND LAPS ANALYSIS STILL
SHOWS PLENTY OF CIN CAPPING MODEST INSTBY. STILL CAN/T RULE OUT A
COUPLE OF SHWRS OR EVEN TSTM FIRING ON THE HIGHEST NC MTN PEAKS. BUT
WILL KEEP FCST DRY FOR NOW GIVEN THE STRONG NVA. OTHERWISE TEMPS
STILL ON TRACK TO REACH LWR-MID 80S THIS AFTN ACRS LWR ELEVATIONS.
TONIGHT AND MONDAY...UPPER RIDGE AXIS WILL SHIFT EAST FROM THE TN/OH
VALLEYS TO OVER THE CWFA BY MONDAY AFTN. MEANWHILE...SFC HIGH
PRESSURE WILL QUICKLY SHIFT FROM THE GREAT LAKES TO OFF THE MID
ATLANTIC COAST BY MONDAY AFTN. GUIDANCE CONTINUES TO TREND WITH LESS
MOVEMENT OF A WEAK QUASI-STATIONARY FRONT EXTENDING SE FROM LOW
PRESSURE TRACKING EAST ACRS THE MIDWEST TO THE SC
COAST...ESSENTIALLY BISECTING THE CWFA. AS THE LOW TRACKS EAST INTO
NRN IN/OH ON MONDAY...LLVL FLOW TURNS SWLY AND PROVIDES A BROAD AREA
OF WEAK-MODERATE ISENT LIFT ALONG THE FRONTAL ZONE. GUIDANCE IN
AGREEMENT ON MOST OF THE CLOUDS AND ANY PRECIP THAT MAY DEVELOP TO
REMAIN GENERALLY NE OF THE CWFA. STILL COULD SEE SOME FOG AND
STRATUS ACRS THE NC FOOTHILLS AND PIEDMONT OVERNIGHT INTO MONDAY
MORNING. THE REST OF THE AREA WILL BE IN A DESTABILIZING WARM
SECTOR...WITH FCST SNDGS SHOWING MODERATE SBCAPE AND VERY LITTLE
CIN. ALSO...WITH RIDGE AXIS CROSSING THE AREA...THE MID LVLS SHUD BE
LESS SUPPRESSED. SO EXPECTING SCATTERED SHWRS/TSTMS ACRS THE MTNS
WITH WESTERLY 0-6 KM SHEAR OF 20-30 KTS HELPING SOME OF THE ACTIVITY
MOVE INTO THE PIEDMONT. DECENT MID LVL LAPSE RATES AND DRY AIR
SUPPORT AT LEAST A NOMINAL LARGE HAIL/DAMAGING WIND THREAT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM SUNDAY... EXPECT CONVECTION TO TAPER OFF MON EVE WITH
COOLING. THEN AS A WEAK SHORTWAVE MOVES THRU THE FLAT UPPER RIDGE
TUE...LOOK FOR SCT SHWRS AND TSTMS TO REDEVELOP ACROSS MAINLY THE
MTNS AND ADJACENT FOOTHILLS IN THE AFTN. CONVECTION WILL DIMINISH
WITH COOLING TUE NIGHT. RIDGE REBOUNDS ON WED AND WITH LESS FORCING
AND SLIGHTLY DRYER AIR...WE FEATURE ONLY SLIGHT CHC POPS FOR THE
MTNS WED AFTN. TEMPS REMAIN WELL ABOVE AVG BOTH DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 200 PM SUNDAY...UPPER RIDGE REMAINS OVER THE REGION THU...THEN
WEAKENS AND RETREATS W FRI AS A SHORTWAVE TROF MOVES THRU THE UPPER
FLOW...LEAVING THE AREA OPEN TO A SERIES OF FAIRLY WEAK IMPULSES
THRU THE WEEKEND. MEANWHILE...THE SFC RIDGE OFF THE E COAST WILL
KEEP THE AREA IN WARM...MOIST S FLOW THU-FRI...BEFORE A WEAK COLD
FRONT BEGINS TO SINK S ACROSS THE OH VALLEY TOWARD THE CWA NEXT
WEEKEND. THIS IS SLOWER AND WEAKER REGARDING THE FRONT THAN PREV
RUNS AND MODELS ARE IN DECENT AGREEMENT ON THIS. ONCE THE SFC
BOUNDARY GETS CLOSE TO THE AREA ON SUN IT`S EXPECTED TO DISSIPATE
WITH LITTLE IMPACT FOR THE CWA. BOTTOM LINE IS FOR SLIGHT CHC OF
DIURNALLY ENHANCED POPS...MAINLY OVER THE MTNS...WITH WELL ABOVE AVG
TEMPS THRU THE EXTENDED.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
AT KCLT...A WEAK BACK DOOR COLD FRONT WILL SETTLE NEAR THE AIRFIELD
TONIGHT. THE NAM AND RUC BUFKIT SOUNDINGS BOTH DEVELOP EITHER LOW
CLOUDS...LIFR OR BLO...OR FOG OVERNIGHT. OTHER MODEL GUIDANCE DOES
THE SAME THING. THERE IS AN EVIDENT DEWPOINT RIDGE ACROSS NRN SC AND
SRN NC PUSHING INTO THE REGION. LOW CLOUDS SHOULD DEVELOP IN THE
AREAS OF HIGHER DEWPOINTS AND MOVE INTO THE AIRFIELD FROM THE EAST
BY AROUND 08-09 UTC. THE CLOUDS SHOULD MIX OUT BY 13-14 UTC WITH SCT
CU AROUND MUCH OF THE DAY. NOT EXPECTING THE BACK DOOR FRONT TO TURN
THE WINDS OUT OF THE NORTH...THOUGH THE MAY GO LIGHT AND VARIABLE
LATE.
ELSEWHERE...THE CLT PART OF THE DISCUSSION APPLIES TO KHKY AS WELL.
AT KAVL VALLEY FOG AND STRATUS IS EXPECTED AGAIN...THOUGH IT MAY
STAY A LITTLE OFF OF THE AIRFIELD. AT THE UPSTATE SITES THE LOW
CLOUDS SHOULD STAY A LITTLE WAYS EAST OF ALL THE AIRFIELDS...THOUGH
SOME MVFR FOG IS POSSIBLE AT KAND TOWARD DAYBREAK. SCT SHRA/TSTMS
ARE EXPECTED OVER THE MTNS AND FOOTHILLS TMRW AFTN. COVERAGE IS NOT
GREAT ENUF TO INCLUDE ANYTHING IN THE TAFS...BUT GENERAL AVIATION
PILOTS SHOULD BE AWARE THAT THERE WILL BE STORMS AROUND KAVL AND
KHKY IN THE AFTN.
OUTLOOK...A RETURN TO MORE CLIMATOLOGICAL DIURNALLY DRIVEN
CONVECTION EXPECTED THRU MIDWEEK. MORNING FOG AND/OR STRATUS
POSSIBLE EACH MORNING WITH PERSISTENT MOIST SOUTHERLY LLVL FLOW ACRS
THE REGION.
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...PAT
NEAR TERM...MCAVOY
SHORT TERM...RB
LONG TERM...RB
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
754 PM EDT SUN APR 29 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL REMAIN OVER THE NORTHWEST PIEDMONT AND
NORTHERN FOOTHILLS OF NORTH CAROLINA TODAY...BEFORE LIFTING NORTH AS
A WARM FRONT ON MONDAY. HIGH PRESSURE WILL THEN MOVE OVER THE AREA
AND DOMINATE THE WEATHER THROUGH THE REST OF THE WEEK. THE NEXT COLD
FRONT IS EXPECTED TO MOVE INTO THE AREA JUST IN TIME FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH MONDAY/...
AS OF 755 PM...CU FIELD IS HANGING ON ACROSS THE BLUE RIDGE...WITH A
LITTLE MORE HIGH CLOUD COVER OVERSPREADING THE REGION. STILL NOT
EXPECTING ANY CONVECTION TO DEVELOP OUT OF THE MTN CLOUDS AS CIN
VALUES ARE BEGINNING TO INCREASE ACROSS THE REGION. THE REST OF THE
FORECAST LOOKS GOOD.
AS OF 500 PM...TEMPS ARE A LITTLE COOLER THAN PREDICTED OVER THE
REGION THIS AFTN...MAINLY OVER THE UPSTATE AND NE GA. MAXES HAVE
BEEN UPDATED TO REFLECT THIS TREND. PERSISTENT...UPSLOPE INDUCED CU
CONTINUES ACROSS THE BLUE RIDGE. THE CU MAY LAST A WAYS PAST SUNSET
IN THESE AREAS...AIDED BY THE UPSLOPE.
PREVIOUS DISCUSSION...
AS OF 145 PM...UPPER RIDGE CONTINUES TO BUILD OVER THE SOUTHEAST
STATES TODAY...WITH AXIS STILL JUST TO THE WEST OF THE CWFA. CLOUDS
ON VIS LOOK SUPPRESSED UNDER THE RIDGE...AND LAPS ANALYSIS STILL
SHOWS PLENTY OF CIN CAPPING MODEST INSTBY. STILL CAN/T RULE OUT A
COUPLE OF SHWRS OR EVEN TSTM FIRING ON THE HIGHEST NC MTN PEAKS. BUT
WILL KEEP FCST DRY FOR NOW GIVEN THE STRONG NVA. OTHERWISE TEMPS
STILL ON TRACK TO REACH LWR-MID 80S THIS AFTN ACRS LWR ELEVATIONS.
TONIGHT AND MONDAY...UPPER RIDGE AXIS WILL SHIFT EAST FROM THE TN/OH
VALLEYS TO OVER THE CWFA BY MONDAY AFTN. MEANWHILE...SFC HIGH
PRESSURE WILL QUICKLY SHIFT FROM THE GREAT LAKES TO OFF THE MID
ATLANTIC COAST BY MONDAY AFTN. GUIDANCE CONTINUES TO TREND WITH LESS
MOVEMENT OF A WEAK QUASI-STATIONARY FRONT EXTENDING SE FROM LOW
PRESSURE TRACKING EAST ACRS THE MIDWEST TO THE SC
COAST...ESSENTIALLY BISECTING THE CWFA. AS THE LOW TRACKS EAST INTO
NRN IN/OH ON MONDAY...LLVL FLOW TURNS SWLY AND PROVIDES A BROAD AREA
OF WEAK-MODERATE ISENT LIFT ALONG THE FRONTAL ZONE. GUIDANCE IN
AGREEMENT ON MOST OF THE CLOUDS AND ANY PRECIP THAT MAY DEVELOP TO
REMAIN GENERALLY NE OF THE CWFA. STILL COULD SEE SOME FOG AND
STRATUS ACRS THE NC FOOTHILLS AND PIEDMONT OVERNIGHT INTO MONDAY
MORNING. THE REST OF THE AREA WILL BE IN A DESTABILIZING WARM
SECTOR...WITH FCST SNDGS SHOWING MODERATE SBCAPE AND VERY LITTLE
CIN. ALSO...WITH RIDGE AXIS CROSSING THE AREA...THE MID LVLS SHUD BE
LESS SUPPRESSED. SO EXPECTING SCATTERED SHWRS/TSTMS ACRS THE MTNS
WITH WESTERLY 0-6 KM SHEAR OF 20-30 KTS HELPING SOME OF THE ACTIVITY
MOVE INTO THE PIEDMONT. DECENT MID LVL LAPSE RATES AND DRY AIR
SUPPORT AT LEAST A NOMINAL LARGE HAIL/DAMAGING WIND THREAT.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM SUNDAY... EXPECT CONVECTION TO TAPER OFF MON EVE WITH
COOLING. THEN AS A WEAK SHORTWAVE MOVES THRU THE FLAT UPPER RIDGE
TUE...LOOK FOR SCT SHWRS AND TSTMS TO REDEVELOP ACROSS MAINLY THE
MTNS AND ADJACENT FOOTHILLS IN THE AFTN. CONVECTION WILL DIMINISH
WITH COOLING TUE NIGHT. RIDGE REBOUNDS ON WED AND WITH LESS FORCING
AND SLIGHTLY DRYER AIR...WE FEATURE ONLY SLIGHT CHC POPS FOR THE
MTNS WED AFTN. TEMPS REMAIN WELL ABOVE AVG BOTH DAYS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 200 PM SUNDAY...UPPER RIDGE REMAINS OVER THE REGION THU...THEN
WEAKENS AND RETREATS W FRI AS A SHORTWAVE TROF MOVES THRU THE UPPER
FLOW...LEAVING THE AREA OPEN TO A SERIES OF FAIRLY WEAK IMPULSES
THRU THE WEEKEND. MEANWHILE...THE SFC RIDGE OFF THE E COAST WILL
KEEP THE AREA IN WARM...MOIST S FLOW THU-FRI...BEFORE A WEAK COLD
FRONT BEGINS TO SINK S ACROSS THE OH VALLEY TOWARD THE CWA NEXT
WEEKEND. THIS IS SLOWER AND WEAKER REGARDING THE FRONT THAN PREV
RUNS AND MODELS ARE IN DECENT AGREEMENT ON THIS. ONCE THE SFC
BOUNDARY GETS CLOSE TO THE AREA ON SUN IT`S EXPECTED TO DISSIPATE
WITH LITTLE IMPACT FOR THE CWA. BOTTOM LINE IS FOR SLIGHT CHC OF
DIURNALLY ENHANCED POPS...MAINLY OVER THE MTNS...WITH WELL ABOVE AVG
TEMPS THRU THE EXTENDED.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AT KCLT...A WEAK BACK DOOR COLD FRONT WILL SETTLE NEAR THE AIRFIELD
TONIGHT. THE NAM AND RUC BUFKIT SOUNDINGS BOTH DEVELOP EITHER LOW
CLOUDS...LIFR OR BLO...OR FOG OVERNIGHT. OTHER MODEL GUIDANCE DOES
THE SAME THING. THERE IS AN EVIDENT DEWPOINT RIDGE ACROSS NRN SC AND
SRN NC PUSHING INTO THE REGION. LOW CLOUDS SHOULD DEVELOP IN THE
AREAS OF HIGHER DEWPOINTS AND MOVE INTO THE AIRFIELD FROM THE EAST
BY AROUND 08-09 UTC. THE CLOUDS SHOULD MIX OUT BY 13-14 UTC WITH SCT
CU AROUND MUCH OF THE DAY. NOT EXPECTING THE BACK DOOR FRONT TO TURN
THE WINDS OUT OF THE NORTH...THOUGH THE MAY GO LIGHT AND VARIABLE
LATE.
ELSEWHERE...THE CLT PART OF THE DISCUSSION APPLIES TO KHKY AS WELL.
AT KAVL VALLEY FOG AND STRATUS IS EXPECTED AGAIN...THOUGH IT MAY
STAY A LITTLE OFF OF THE AIRFIELD. AT THE UPSTATE SITES THE LOW
CLOUDS SHOULD STAY A LITTLE WAYS EAST OF ALL THE AIRFIELDS...THOUGH
SOME MVFR FOG IS POSSIBLE AT KAND TOWARD DAYBREAK. SCT SHRA/TSTMS
ARE EXPECTED OVER THE MTNS AND FOOTHILLS TMRW AFTN. COVERAGE IS NOT
GREAT ENUF TO INCLUDE ANYTHING IN THE TAFS...BUT GENERAL AVIATION
PILOTS SHOULD BE AWARE THAT THERE WILL BE STORMS AROUND KAVL AND
KHKY IN THE AFTN.
OUTLOOK...A RETURN TO MORE CLIMATOLOGICAL DIURNALLY DRIVEN
CONVECTION EXPECTED THRU MIDWEEK. MORNING FOG AND/OR STRATUS
POSSIBLE EACH MORNING WITH PERSISTENT MOIST SOUTHERLY LLVL FLOW ACRS
THE REGION.
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...PAT
NEAR TERM...MCAVOY
SHORT TERM...RB
LONG TERM...RB
AVIATION...MCAVOY
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
206 PM EDT SAT APR 28 2012
.SYNOPSIS...
A SURFACE FRONT ACROSS NORTHEAST GEORGIA AND THE UPSTATE OF SOUTH
CAROLINA WILL SLOWLY LIFT NORTH TONIGHT AS A WARM FRONT...BUT
WILL RETURN BACK TO THE SOUTHWEST LATE ON SUNDAY. ON MONDAY...HIGH
PRESSURE TO THE NORTHEAST WILL AFFECT THE REGION WITH COOLER
TEMPERATURES. THE HIGH WILL MOVE OFF THE EAST COAST ON TUESDAY...
ALLOWING A RETURN OF WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 130 PM... NO MAJOR CHANGES TO EARLY AFTERNOON FORECAST.
SATELLITE IMAGERY SHOWS CLOUDS EAST OF MOUNTAINS ARE ERODING FROM
SOUTHWEST TO NORTHEAST.
AT 1030 AM... CLOUDS NORTH OF SURFACE BOUNDARY EAST
OF MOUNTAINS WILL CONTINUE INTO THE AFTERNOON... BUT EROSION IS
ALREADY OCCURRING AROUND THE WESTERN AND SOUTHWESTERN PERIPHERY OF
THE CWA AND IN THE FOOTHILLS. MOIST LOW-LEVEL AIR HAVING A HARD
PENETRATING TOO FAR WEST ACROSS THE MOUNTAINS... WHICH IS
TYPICAL... SO THAT PART OF CWA WILL EXPERIENCE A FAIR AMOUNT OF
SUN UNTIL CONVECTIVE CLOUDS FILL IN SOME OF THE GAPS. THE MODELS
ARE NEARLY UNANIMOUS IN THEIR AGREEMENT REGARDING A GRADUAL
NORTHWARD MOVEMENT OF THE SURFACE BOUNDARY ACROSS THE FORECAST
AREA THIS AFTERNOON AND EVENING. AS THAT OCCURS... THE WEAK CAD-
LIKE RIDGE OF HIGH PRESSURE EAST OF THE MOUNTAINS WILL RECEDE...
BUT APPEARS THAT QUITE A BIT OF LOW- LEVEL MOISTURE WILL REMAIN
BEHIND. RUC INDICATES THAT SOME MODEST CAPE... 500+ J/KG... WILL
EXIST THIS AFTERNOON NEAR BOUNDARY OVER SOUTHERN PORTION OF CWA.
MODEL PROFILES SHOW THAT A FAIRLY WARM LAYER WOULD HAVE TO BE
OVERCOME TO RELEASE THE CAPE... SO DOES NOT APPEAR LIKELY THAT
CONVECTIVE PRECIPITATION WILL DEVELOP THERE. A SLIGHTLY BETTER
CHANCE EXISTS OVER THE MOUNTAINS WHERE HIGHER CAPE CONSISTING OF
INCREASINGLY UNSTABLE LOW AND MID-LEVEL LAPSE RATES WILL SPREAD
OVER THOSE ZONES FROM THE SOUTHWEST BY LATE AFTERNOON. HEATING
OVER THE HIGHER TERRAIN COULD PROMOTE DEVELOPMENT OF WIDELY
SCATTERED SHOWERS OR THUNDERSTORMS.
PREVIOUS DISCUSSION...
AT 320 AM...STATIONARY FRONT OVER THE AREA IS KEEPING TD/S HIGH
WHILE THE MID AND UPPER LEVELS SLOWLY BEGIN TO BECOME FREE OF DEBRIS
CLOUDINESS. DENSE FG IS SETTING UP ACROSS THE WRN UPSTATE AND NE
GA...HOWEVER VISIBILITY IS GOING BACK AND FORTH BTW 1/4SM RANGE AND
BTW 1SM-2SM. ENOUGH VARIABILITY AND NOT WIDESPREAD ENOUGH TO ISSUE A
DFA. OVER NEAR CLT AND THE NW PIEDMONT...LLVL STCU IS FORMING ALONG
A WEAK WEDGE FRONT. EXPECT THESE CLOUDS TO PERSIST THROUGH ABOUT MID
DAY...PERHAPS A BIT LONGER AS H85 WARM FRONT ADVANCES NORTH OVER THE
STRENGTHENING. NOT SEEING ENOUGH DEPTH OF MOISTURE OR ELEVATED
INSTABILITY TO INCLUDE PRECIPITATION. CLOUDS WILL BE THE MAIN WORRY
AS FAR AS MAX TEMPS GO. RIGHT NOW A DECENT TEMP GRADIENT IS
ADVERTISED N/S. MAXES SHOULD BE IN THE M80S SOUTH WHILE THE NRN
PIEDMONT SHOULD ONLY GET INTO THE MID TO UPPER 60S. ISOL CONVECTION
IS POSSIBLE ACROSS THE NC MTNS THIS AFTERNOON...AS LLVL WINDS SHIFT
S/LY AND SUPPLY MECHANICAL LIFT TO A MODESTLY UNSTABLE ENVIRONMENT.
MAXES IN THE MTN VALLEYS WILL BE IN M70S.
NO GOOD CHANCE PRECIP OVERNIGHT AS WEDGE DISSIPATES AND SHIFTS EAST.
ALSO THE FRONTAL BOUNDARY WILL BE LOCATED OVER SRN VA. A GOOD AMOUNT
OF CLEARING IS ANTICIPATED OVERNIGHT...HOWEVER THE H100-H85 LAYER
MOISTURE REMAINS MOIST ENOUGH TO SUPPORT SCT STCU ACROSS AT LEAST
THE NRN ZONES. THIS COMBINED WITH LLVL WAA WILL KEEP MIN TEMPS A
COUPLE CATS ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE SHORT RANGE PART OF THE FORECAST STILL
LOOKS LIKE IT WILL BE DOMINATED BY LOW LEVEL FORCING AND MESOSCALE
PROCESSES. AN UPPER ANTICYCLONE WILL REMAIN IN PLACE OVER THE DEEP
SOUTH WITH AN UPPER RIDGE AMPLIFYING OVERHEAD ON SUNDAY AND SUNDAY
NIGHT. ALTHO THE RIDGE FLATTENS SOMEWHAT LATE MONDAY AND MONDAY
NIGHT...ALL THE SHORT WAVES AND UPPER FORCING REMAINS SHUNTED TO THE
NORTH OF THE REGION. THE LOW LEVEL FORCING IS STILL EXPECTED TO COME
IN THE FORM OF A BACK DOOR COLD FRONT THAT WILL MOVE INTO THE WRN
PIEDMONT AND NC FOOTHILLS ON SUNDAY AFTERNOON. THE TIMING IS
QUESTIONABLE...WITH THE NAM BEING A BIT FASTER TO ESTABLISH THE
MOIST E/NE FLOW. THE FORECAST FAVORS THE GFS A BIT MORE THAN THE NAM
IN THAT PRECIP CHANCES DO NOT CLIMB INTO THE CHANCE RANGE UNTIL THE
EARLY EVENING OVER THE NW PIEDMONT. HIGH TEMPS WERE NUDGED TOWARD A
GUIDANCE BLEND. THE FRONT SHOULD CONTINUE TO PUSH SW ACROSS THE AREA
EAST OF THE MTNS SUNDAY NIGHT. CONVERGENCE ALONG THE BOUNDARY AND
EASTERLY UPSLOPE SUGGEST KEEPING PRECIP IN THE FORECAST OVERNIGHT...
WITH THE HIGHEST CHANCES NEAR THE BLUE RIDGE. ON MONDAY...THE
SITUATION LOOKS WEDGE LIKE WITH A PIECE OF THE SURFACE HIGH BROKEN
OFF NEAR THE MID ATLANTIC COAST. IN THESE SITUATIONS...THE NAM SEEMS
TO HAVE A BETTER HANDLE ON KEEPING THE COLD AIR DAMMING IN PLACE
WHILE THE GFS IS TOO QUICK TO DESTROY IT. CLOUDINESS AND LIGHT
PRECIP SHOULD BE EXPECTED IN THE MORNING...WITH LITTLE IMPROVEMENT
OVER THE USUAL DAMMING LOCATIONS UNTIL MAYBE VERY LATE IN THE DAY.
SOME LOCATIONS WILL NOT MAKE IT OUT OF THE 60S. WILL NOT MAKE ANY
BIG CHANGES TO HIGH TEMPS...BUT SEE WHERE THEY COULD BE A CATEGORY
TOO HIGH IF PRECIP DEVELOPS TO A GREATER EXTENT THAN EXPECTED. LIGHT
PRECIP MAY CONTINUE NEAR THE BLUE RIDGE MONDAY NIGHT WITH THE LOW
LEVEL UPGLIDE...AND TEMPS SHOULD REMAIN MILD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM SATURDAY...THE MEDIUM RANGE LOOKS FAIRLY UNEVENTFUL
WITH FLAT UPPER RIDGING IN PLACE THROUGH MOST OF THE PERIOD...AND
SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. AS A RESULT...THE
MODELS LOOK ALMOST SUMMERLIKE...AND FAVOR MAINLY DIURNAL LOW END
CHANCES OF PRECIP THAT FAVOR THE MTNS. DO NOT SEE MUCH OF A REASON
TO MAKE MANY CHANGES TO THE ONGOING FORECAST...UNTIL LATE IN THE
PERIOD. THE LATEST GFS SHOWS A SHORT WAVE MOVING THROUGH ON FRIDAY
AFTERNOON. WHILE THE TIMING IS UNCERTAIN...BOTH MODELS DROP THE NEXT
FRONT DOWN FROM THE NORTH IN THE AFTERNOON...SO PRECIP CHANCES WILL
PROBABLY BE A BIT BETTER THEN COMPARED TO MID WEEK. WITH THAT IN
MIND...THE FORECAST WILL BE BUMPED UP A BIT.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
AT KCLT...SATELLITE IMAGERY SHOWS THE MVFR CLOUD DECK ENCOMPASSING
KCLT IS SHOWING DEFINITE SIGNS OF EROSION... BUT IT WILL STIL TAKE A
LITTLE TIME FOR THE IMPROVEMENT TO REACH THE TERMINAL AREA. BASED ON
SATELLITE AND LATEST LAMP GUIDANCE... CLOUD BASE NEAR 2K FT SHOULD
INCREASE TO AROUND 35 HND FT AS IT DISSIPATES BETWEEN 21Z AND 00Z.
THEREAFTER... EXPECT SCATTERED CLOUDS OVERNIGHT. NEITHER THE NAM OR
GFS INDICATE VISIBILITY RESTRICTION... SO WILL NOT INCLUDE ANY IN
FORECAST AT THE PRESENT TIME. NORTHEAST WIND LESS THAN 10 KT WILL
BECOME LIGHT SOUTHEAST TONIGHT THEN LIGHT AND VARIABLE DURING THE
EARLY MORNING HOURS.
ELSEWHERE... VISIBLE IMAGERY... EXPERIMENTAL CIMSS GOES-R
PRODUCTS... AND SURFACE OBSERVATIONS INDICATE LARGE AREA OF MVFR
CEILING... BETWEEN 2 AND 3K FT... EXTENDS FROM VICINITY KAND
EASTWARD AND NORTHWARD TO ALL TERMINAL SITES EXCEPT KAVL. KAVL WILL
HAVE SCATTERED CLOUDS 4 TO 6 K FT PRODUCING ONLY AN OCCASIONAL
CEILING. MVFR CEILING AT OTHER SITES WILL IMPROVE FROM SOUTHWEST TO
NORTHEAST BECOMING SCATTERED AFTER 00Z. NEITHER THE NAM OR THE GFS
INDICATES WIDESPREAD VISIBILITY RESTRICTIONS SO WILL NOT INCLUDE ANY
IN THE THE FORECASTS AT THE PRESENT TIME. LIGHT NORTHEAST TO EAST
WIND WILL BECOME LIGHT AND VARIABLE OVERNIGHT.
MVFR STRATUS AND STRATOCUMULUS WILL PERSIST INTO THE
AFTERNOON EXCEPT AT KAVL WHERE SCATTERED TO BROKEN CLOUDS NEAR 4K FT
WILL EXIST. BY 20Z EXPECT CLOUD BASES TO LIFT TO 3-4K FT. VISIBILITY
UNRESTRICTED. ISOLATED SHOWERS OR THUNDERSTORMS POSSIBLE OVER HIGHER
TERRAIN NEAR KAVL AFTER 18Z.
OUTLOOK... A WEAK COLD FRONT WILL DROP INTO THE AREA FROM THE
NORTHEAST SUNDAY NIGHT CAUSING MVFR AND LOCAL IFR CONDITIONS IN
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS. THE FRONT WILL REMAIN
IN THE VICINITY THROUGH MID WEEK...RESULTING IN A CONTINUATION OF
UNSETTLED WEATHER... PRIMARLY AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS WITH LOW CEILING AND VISIBILITY.
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...LGL
SHORT TERM...PM
LONG TERM...PM
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1120 AM EDT SAT APR 28 2012
.SYNOPSIS...
A SURFACE FRONT ACROSS NORTHEAST GEORGIA AND THE UPSTATE OF SOUTH
CAROLINA THIS MORNING SHOULD LIFT NORTH TODAY AS A WARM FRONT...BUT
WILL RETURN BACK TO THE SOUTHWEST LATE ON SUNDAY. ON MONDAY...HIGH
PRESSURE TO THE NORTHEAST WILL AFFECT THE REGION WITH COOLER
TEMPERATURES. THE HIGH WILL MOVE OFF THE EAST COAST ON TUESDAY...
ALLOWING A RETURN OF WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1030 AM... CLOUDS NORTH OF SURFACE BOUNDARY EAST OF MOUNTAINS
WILL CONTINUE INTO THE AFTERNOON... BUT EROSION IS ALREADY OCCURRING
AROUND THE WESTERN AND SOUTHWESTERN PERIPHERY OF THE CWA AND IN THE
FOOTHILLS. MOIST LOW-LEVEL AIR HAVING A HARD PENETRATING TOO FAR WEST ACROSS
THE MOUNTAINS... WHICH IS TYPICAL... SO THAT PART OF CWA WILL
EXPERIENCE A FAIR AMOUNT OF SUN UNTIL CONVECTIVE CLOUDS FILL IN SOME
OF THE GAPS. THE MODELS ARE NEARLY UNANIMOUS IN THEIR AGREEMENT
REGARDING A GRADUAL NORTHWARD MOVEMENT OF THE SURFACE BOUNDARY
ACROSS THE FORECAST AREA THIS AFTERNOON AND EVENING. AS THAT
OCCURS... THE WEAK CAD-LIKE RIDGE OF HIGH PRESSURE EAST OF THE
MOUNTAINS WILL RECEDE... BUT APPEARS THAT QUITE A BIT OF LOW-LEVEL
MOISTURE WILL REMAIN BEHIND. RUC INDICATES THAT SOME MODEST CAPE...
500+ J/KG... WILL EXIST THIS AFTERNOON NEAR BOUNDARY OVER SOUTHERN
PORTION OF CWA. MODEL PROFILES SHOW THAT A FAIRLY WARM LAYER WOULD
HAVE TO BE OVERCOME TO RELEASE THE CAPE... SO DOES NOT APPEAR LIKELY
THAT CONVECTIVE PRECIPITATION WILL DEVELOP THERE. A SLIGHTLY BETTER
CHANCE EXISTS OVER THE MOUNTAINS WHERE HIGHER CAPE CONSISTING OF
INCREASINGLY UNSTABLE LOW AND MID-LEVEL LAPSE RATES WILL SPREAD OVER
THOSE ZONES FROM THE SOUTHWEST BY LATE AFTERNOON. HEATING OVER THE
HIGHER TERRAIN COULD PROMOTE DEVELOPMENT OF WIDELY SCATTERED SHOWERS
OR THUNDERSTORMS.
PREVIOUS DISCUSSION...
AT 320 AM...STATIONARY FRONT OVER THE AREA IS KEEPING TD/S HIGH
WHILE THE MID AND UPPER LEVELS SLOWLY BEGIN TO BECOME FREE OF DEBRIS
CLOUDINESS. DENSE FG IS SETTING UP ACROSS THE WRN UPSTATE AND NE
GA...HOWEVER VISIBILITY IS GOING BACK AND FORTH BTW 1/4SM RANGE AND
BTW 1SM-2SM. ENOUGH VARIABILITY AND NOT WIDESPREAD ENOUGH TO ISSUE A
DFA. OVER NEAR CLT AND THE NW PIEDMONT...LLVL STCU IS FORMING ALONG
A WEAK WEDGE FRONT. EXPECT THESE CLOUDS TO PERSIST THROUGH ABOUT MID
DAY...PERHAPS A BIT LONGER AS H85 WARM FRONT ADVANCES NORTH OVER THE
STRENGTHENING. NOT SEEING ENOUGH DEPTH OF MOISTURE OR ELEVATED
INSTABILITY TO INCLUDE PRECIPITATION. CLOUDS WILL BE THE MAIN WORRY
AS FAR AS MAX TEMPS GO. RIGHT NOW A DECENT TEMP GRADIENT IS
ADVERTISED N/S. MAXES SHOULD BE IN THE M80S SOUTH WHILE THE NRN
PIEDMONT SHOULD ONLY GET INTO THE MID TO UPPER 60S. ISOL CONVECTION
IS POSSIBLE ACROSS THE NC MTNS THIS AFTERNOON...AS LLVL WINDS SHIFT
S/LY AND SUPPLY MECHANICAL LIFT TO A MODESTLY UNSTABLE ENVIRONMENT.
MAXES IN THE MTN VALLEYS WILL BE IN M70S.
NO GOOD CHANCE PRECIP OVERNIGHT AS WEDGE DISSIPATES AND SHIFTS EAST.
ALSO THE FRONTAL BOUNDARY WILL BE LOCATED OVER SRN VA. A GOOD AMOUNT
OF CLEARING IS ANTICIPATED OVERNIGHT...HOWEVER THE H100-H85 LAYER
MOISTURE REMAINS MOIST ENOUGH TO SUPPORT SCT STCU ACROSS AT LEAST
THE NRN ZONES. THIS COMBINED WITH LLVL WAA WILL KEEP MIN TEMPS A
COUPLE CATS ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE SHORT RANGE PART OF THE FORECAST STILL
LOOKS LIKE IT WILL BE DOMINATED BY LOW LEVEL FORCING AND MESOSCALE
PROCESSES. AN UPPER ANTICYCLONE WILL REMAIN IN PLACE OVER THE DEEP
SOUTH WITH AN UPPER RIDGE AMPLIFYING OVERHEAD ON SUNDAY AND SUNDAY
NIGHT. ALTHO THE RIDGE FLATTENS SOMEWHAT LATE MONDAY AND MONDAY
NIGHT...ALL THE SHORT WAVES AND UPPER FORCING REMAINS SHUNTED TO THE
NORTH OF THE REGION. THE LOW LEVEL FORCING IS STILL EXPECTED TO COME
IN THE FORM OF A BACK DOOR COLD FRONT THAT WILL MOVE INTO THE WRN
PIEDMONT AND NC FOOTHILLS ON SUNDAY AFTERNOON. THE TIMING IS
QUESTIONABLE...WITH THE NAM BEING A BIT FASTER TO ESTABLISH THE
MOIST E/NE FLOW. THE FORECAST FAVORS THE GFS A BIT MORE THAN THE NAM
IN THAT PRECIP CHANCES DO NOT CLIMB INTO THE CHANCE RANGE UNTIL THE
EARLY EVENING OVER THE NW PIEDMONT. HIGH TEMPS WERE NUDGED TOWARD A
GUIDANCE BLEND. THE FRONT SHOULD CONTINUE TO PUSH SW ACROSS THE AREA
EAST OF THE MTNS SUNDAY NIGHT. CONVERGENCE ALONG THE BOUNDARY AND
EASTERLY UPSLOPE SUGGEST KEEPING PRECIP IN THE FORECAST OVERNIGHT...
WITH THE HIGHEST CHANCES NEAR THE BLUE RIDGE. ON MONDAY...THE
SITUATION LOOKS WEDGE LIKE WITH A PIECE OF THE SURFACE HIGH BROKEN
OFF NEAR THE MID ATLANTIC COAST. IN THESE SITUATIONS...THE NAM SEEMS
TO HAVE A BETTER HANDLE ON KEEPING THE COLD AIR DAMMING IN PLACE
WHILE THE GFS IS TOO QUICK TO DESTROY IT. CLOUDINESS AND LIGHT
PRECIP SHOULD BE EXPECTED IN THE MORNING...WITH LITTLE IMPROVEMENT
OVER THE USUAL DAMMING LOCATIONS UNTIL MAYBE VERY LATE IN THE DAY.
SOME LOCATIONS WILL NOT MAKE IT OUT OF THE 60S. WILL NOT MAKE ANY
BIG CHANGES TO HIGH TEMPS...BUT SEE WHERE THEY COULD BE A CATEGORY
TOO HIGH IF PRECIP DEVELOPS TO A GREATER EXTENT THAN EXPECTED. LIGHT
PRECIP MAY CONTINUE NEAR THE BLUE RIDGE MONDAY NIGHT WITH THE LOW
LEVEL UPGLIDE...AND TEMPS SHOULD REMAIN MILD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM SATURDAY...THE MEDIUM RANGE LOOKS FAIRLY UNEVENTFUL
WITH FLAT UPPER RIDGING IN PLACE THROUGH MOST OF THE PERIOD...AND
SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. AS A RESULT...THE
MODELS LOOK ALMOST SUMMERLIKE...AND FAVOR MAINLY DIURNAL LOW END
CHANCES OF PRECIP THAT FAVOR THE MTNS. DO NOT SEE MUCH OF A REASON
TO MAKE MANY CHANGES TO THE ONGOING FORECAST...UNTIL LATE IN THE
PERIOD. THE LATEST GFS SHOWS A SHORT WAVE MOVING THROUGH ON FRIDAY
AFTERNOON. WHILE THE TIMING IS UNCERTAIN...BOTH MODELS DROP THE NEXT
FRONT DOWN FROM THE NORTH IN THE AFTERNOON...SO PRECIP CHANCES WILL
PROBABLY BE A BIT BETTER THEN COMPARED TO MID WEEK. WITH THAT IN
MIND...THE FORECAST WILL BE BUMPED UP A BIT.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...MVFR STRATUS AROUND 2KT FT EXPECTED TO CONTINUE UNTIL
APPROXIMATELY 20Z THEN LIFT TO ONLY 3-4K FT. VISIBILITY
UNRESTRICTED. NORTH TO NORTHEAST SURFACE WIND 5 TO 10 KT.
ELSEWHERE...MVFR STRATUS AND STRATOCUMULUS WILL PERSIST INTO THE
AFTERNOON EXCEPT AT KAVL WHERE SCATTERED TO BROKEN CLOUDS NEAR 4K FT
WILL EXIST. BY 20Z EXPECT CLOUD BASES TO LIFT TO 3-4K FT. VISIBILITY
UNRESTRICTED. ISOLATED SHOWERS OR THUNDERSTORMS POSSIBLE OVER HIGHER
TERRAIN NEAR KAVL AFTER 18Z.
OUTLOOK...ANOTHER WEAK COLD FRONT WILL DROP INTO THE AREA BY
SUNDAY...ENHANCING SHOWER/TS CHANCES ONCE AGAIN. THE FRONT WILL
REMAIN IN THE VICINITY OF THE AREA THROUGH THE FIRST PART OF THE NEW
WORK WEEK...RESULTING IN CONTINUATION OF UNSETTLED WEATHER/PM
SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS.
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...LGL
SHORT TERM...PM
LONG TERM...PM
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1034 AM EDT SAT APR 28 2012
.SYNOPSIS...
A SURFACE FRONT ACROSS NORTHEAST GEORGIA AND THE UPSTATE OF SOUTH
CAROLINA THIS MORNING SHOULD LIFT NORTH TODAY AS A WARM FRONT...BUT
WILL RETURN BACK TO THE SOUTHWEST LATE ON SUNDAY. ON MONDAY...HIGH
PRESSURE TO THE NORTHEAST WILL AFFECT THE REGION WITH COOLER
TEMPERATURES. THE HIGH WILL MOVE OFF THE EAST COAST ON TUESDAY...
ALLOWING A RETURN OF WARMER WEATHER.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 1030 AM... CLOUDS NORTH OF SURFACE BOUNDARY EAST OF MOUNTAINS
WILL CONTINUE INTO THE AFTERNOON... BUT EROSION IS ALREADY OCCURRING
AROUND THE WESTERN AND SOUTHWESTERN PERIPHERY OF THE CWA AND IN THE
FOOTHILLS. MOIST LOW-LEVEL AIR HAVING A HARD PENETRATING TOO FAR WEST ACROSS
THE MOUNTAINS... WHICH IS TYPICAL... SO THAT PART OF CWA WILL
EXPERIENCE A FAIR AMOUNT OF SUN UNTIL CONVECTIVE CLOUDS FILL IN SOME
OF THE GAPS. THE MODELS ARE NEARLY UNANIMOUS IN THEIR AGREEMENT
REGARDING A GRADUAL NORTHWARD MOVEMENT OF THE SURFACE BOUNDARY
ACROSS THE FORECAST AREA THIS AFTERNOON AND EVENING. AS THAT
OCCURS... THE WEAK CAD-LIKE RIDGE OF HIGH PRESSURE EAST OF THE
MOUNTAINS WILL RECEDE... BUT APPEARS THAT QUITE A BIT OF LOW-LEVEL
MOISTURE WILL REMAIN BEHIND. RUC INDICATES THAT SOME MODEST CAPE...
500+ J/KG... WILL EXIST THIS AFTERNOON NEAR BOUNDARY OVER SOUTHERN
PORTION OF CWA. MODEL PROFILES SHOW THAT A FAIRLY WARM LAYER WOULD
HAVE TO BE OVERCOME TO RELEASE THE CAPE... SO DOES NOT APPEAR LIKELY
THAT CONVECTIVE PRECIPITATION WILL DEVELOP THERE. A SLIGHTLY BETTER
CHANCE EXISTS OVER THE MOUNTAINS WHERE HIGHER CAPE CONSISTING OF
INCREASINGLY UNSTABLE LOW AND MID-LEVEL LAPSE RATES WILL SPREAD OVER
THOSE ZONES FROM THE SOUTHWEST BY LATE AFTERNOON. HEATING OVER THE
HIGHER TERRAIN COULD PROMOTE DEVELOPMENT OF WIDELY SCATTERED SHOWERS
OR THUNDERSTORMS.
PREVIOUS DISCUSSION...
AT 320 AM...STATIONARY FRONT OVER THE AREA IS KEEPING TD/S HIGH
WHILE THE MID AND UPPER LEVELS SLOWLY BEGIN TO BECOME FREE OF DEBRIS
CLOUDINESS. DENSE FG IS SETTING UP ACROSS THE WRN UPSTATE AND NE
GA...HOWEVER VISIBILITY IS GOING BACK AND FORTH BTW 1/4SM RANGE AND
BTW 1SM-2SM. ENOUGH VARIABILITY AND NOT WIDESPREAD ENOUGH TO ISSUE A
DFA. OVER NEAR CLT AND THE NW PIEDMONT...LLVL STCU IS FORMING ALONG
A WEAK WEDGE FRONT. EXPECT THESE CLOUDS TO PERSIST THROUGH ABOUT MID
DAY...PERHAPS A BIT LONGER AS H85 WARM FRONT ADVANCES NORTH OVER THE
STRENGTHENING. NOT SEEING ENOUGH DEPTH OF MOISTURE OR ELEVATED
INSTABILITY TO INCLUDE PRECIPITATION. CLOUDS WILL BE THE MAIN WORRY
AS FAR AS MAX TEMPS GO. RIGHT NOW A DECENT TEMP GRADIENT IS
ADVERTISED N/S. MAXES SHOULD BE IN THE M80S SOUTH WHILE THE NRN
PIEDMONT SHOULD ONLY GET INTO THE MID TO UPPER 60S. ISOL CONVECTION
IS POSSIBLE ACROSS THE NC MTNS THIS AFTERNOON...AS LLVL WINDS SHIFT
S/LY AND SUPPLY MECHANICAL LIFT TO A MODESTLY UNSTABLE ENVIRONMENT.
MAXES IN THE MTN VALLEYS WILL BE IN M70S.
NO GOOD CHANCE PRECIP OVERNIGHT AS WEDGE DISSIPATES AND SHIFTS EAST.
ALSO THE FRONTAL BOUNDARY WILL BE LOCATED OVER SRN VA. A GOOD AMOUNT
OF CLEARING IS ANTICIPATED OVERNIGHT...HOWEVER THE H100-H85 LAYER
MOISTURE REMAINS MOIST ENOUGH TO SUPPORT SCT STCU ACROSS AT LEAST
THE NRN ZONES. THIS COMBINED WITH LLVL WAA WILL KEEP MIN TEMPS A
COUPLE CATS ABOVE NORMAL.
&&
.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 245 AM SATURDAY...THE SHORT RANGE PART OF THE FORECAST STILL
LOOKS LIKE IT WILL BE DOMINATED BY LOW LEVEL FORCING AND MESOSCALE
PROCESSES. AN UPPER ANTICYCLONE WILL REMAIN IN PLACE OVER THE DEEP
SOUTH WITH AN UPPER RIDGE AMPLIFYING OVERHEAD ON SUNDAY AND SUNDAY
NIGHT. ALTHO THE RIDGE FLATTENS SOMEWHAT LATE MONDAY AND MONDAY
NIGHT...ALL THE SHORT WAVES AND UPPER FORCING REMAINS SHUNTED TO THE
NORTH OF THE REGION. THE LOW LEVEL FORCING IS STILL EXPECTED TO COME
IN THE FORM OF A BACK DOOR COLD FRONT THAT WILL MOVE INTO THE WRN
PIEDMONT AND NC FOOTHILLS ON SUNDAY AFTERNOON. THE TIMING IS
QUESTIONABLE...WITH THE NAM BEING A BIT FASTER TO ESTABLISH THE
MOIST E/NE FLOW. THE FORECAST FAVORS THE GFS A BIT MORE THAN THE NAM
IN THAT PRECIP CHANCES DO NOT CLIMB INTO THE CHANCE RANGE UNTIL THE
EARLY EVENING OVER THE NW PIEDMONT. HIGH TEMPS WERE NUDGED TOWARD A
GUIDANCE BLEND. THE FRONT SHOULD CONTINUE TO PUSH SW ACROSS THE AREA
EAST OF THE MTNS SUNDAY NIGHT. CONVERGENCE ALONG THE BOUNDARY AND
EASTERLY UPSLOPE SUGGEST KEEPING PRECIP IN THE FORECAST OVERNIGHT...
WITH THE HIGHEST CHANCES NEAR THE BLUE RIDGE. ON MONDAY...THE
SITUATION LOOKS WEDGE LIKE WITH A PIECE OF THE SURFACE HIGH BROKEN
OFF NEAR THE MID ATLANTIC COAST. IN THESE SITUATIONS...THE NAM SEEMS
TO HAVE A BETTER HANDLE ON KEEPING THE COLD AIR DAMMING IN PLACE
WHILE THE GFS IS TOO QUICK TO DESTROY IT. CLOUDINESS AND LIGHT
PRECIP SHOULD BE EXPECTED IN THE MORNING...WITH LITTLE IMPROVEMENT
OVER THE USUAL DAMMING LOCATIONS UNTIL MAYBE VERY LATE IN THE DAY.
SOME LOCATIONS WILL NOT MAKE IT OUT OF THE 60S. WILL NOT MAKE ANY
BIG CHANGES TO HIGH TEMPS...BUT SEE WHERE THEY COULD BE A CATEGORY
TOO HIGH IF PRECIP DEVELOPS TO A GREATER EXTENT THAN EXPECTED. LIGHT
PRECIP MAY CONTINUE NEAR THE BLUE RIDGE MONDAY NIGHT WITH THE LOW
LEVEL UPGLIDE...AND TEMPS SHOULD REMAIN MILD.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 330 AM SATURDAY...THE MEDIUM RANGE LOOKS FAIRLY UNEVENTFUL
WITH FLAT UPPER RIDGING IN PLACE THROUGH MOST OF THE PERIOD...AND
SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. AS A RESULT...THE
MODELS LOOK ALMOST SUMMERLIKE...AND FAVOR MAINLY DIURNAL LOW END
CHANCES OF PRECIP THAT FAVOR THE MTNS. DO NOT SEE MUCH OF A REASON
TO MAKE MANY CHANGES TO THE ONGOING FORECAST...UNTIL LATE IN THE
PERIOD. THE LATEST GFS SHOWS A SHORT WAVE MOVING THROUGH ON FRIDAY
AFTERNOON. WHILE THE TIMING IS UNCERTAIN...BOTH MODELS DROP THE NEXT
FRONT DOWN FROM THE NORTH IN THE AFTERNOON...SO PRECIP CHANCES WILL
PROBABLY BE A BIT BETTER THEN COMPARED TO MID WEEK. WITH THAT IN
MIND...THE FORECAST WILL BE BUMPED UP A BIT.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
AT KCLT...MVFR STRATUS AROUND 2KT FT EXPECTED TO CONTINUE UNTIL
APPROXIMATELY 20Z THEN LIFT TO ONLY 3-4K FT. AROUND 00Z CEILING
AOA 10K FT WILL BECOME SCATTERED. VISIBILITY UNRESTRICTED. NORTH
TO NORTHEAST SURFACE WIND 5 TO 10 KT.
ELSEWHERE...MVFR STRATUS AND STRATOCUMULUS WILL PERSIST INTO THE
AFTERNOON EXCEPT AT KAVL WHERE SCATTERED TO BROKEN CLOUDS NEAR 4K FT
WILL EXIST. BY 20Z EXPECT CLOUD BASES TO LIFT TO 3-4K FT. VISIBILITY
UNRESTRICTED. ISOLATED SHOWERS OR THUNDERSTORMS POSSIBLE OVER HIGHER
TERRAIN NEAR KAVL AFTER 18Z.
OUTLOOK...ANOTHER WEAK COLD FRONT WILL DROP INTO THE AREA BY
SUNDAY...ENHANCING SHOWER/TS CHANCES ONCE AGAIN. THE FRONT WILL
REMAIN IN THE VICINITY OF THE AREA THROUGH THE FIRST PART OF THE NEW
WORK WEEK...RESULTING IN CONTINUATION OF UNSETTLED WEATHER/PM
SHOWERS AND STORMS AND POSSIBLE RESTRICTIONS.
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...LGL
SHORT TERM...PM
LONG TERM...PM
AVIATION...LGL
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 PM CDT SAT APR 28 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY
315 PM CDT SAT APR 28 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES SUNDAY AFTERNOON
INTO MONDAY...THEN TEMPERATURES AND PRECIPITATION CHANCES TUESDAY.
LATEST MOSAIC RADAR INDICATING FRONTOGENETICAL BAND EXTENDING FROM
LAKE MICHIGAN TO WESTERN MINNESOTA WEAKENING AND SHRINKING...THIS
IS IN AGREEMENT WITH THE 28.18Z RUC 700-600MB FN VECTOR CONVERGENCE
WEAKENING THE FRONTOGENETICAL BAND THIS AFTERNOON INTO THIS
EVENING.
THE 28.12Z GFS/NAM ARE IN PRETTY GOOD AGREEMENT IN LIFTING UPPER
LEVEL LOW OVER THE NORTHERN PLAINS NORTHWARD INTO CANADA SUNDAY
NIGHT AND DEVELOPING SOUTHWESTERLY FLOW ALOFT MONDAY NIGHT INTO
TUESDAY. DPROG/DT OF THE 28.12Z GFS AND NAM SHOW SHORTWAVE TROUGH
WRAPPING AROUND THE UPPER LEVEL LOW INTO THE AREA FASTER THE LAST
SEVERAL RUNS. CONFIDENCE IS INCREASING PRECIPITATION WILL
OVERSPREAD THE REGION SUNDAY AFTERNOON. NO SIGNIFICANT DIFFERENCES
NOTED BETWEEN THE 28.12Z DETERMINISTIC MODELS.
TONIGHT INTO MONDAY...FRONTOGENETICAL BAND OVER OVER WESTERN
AND CENTRAL WISCONSIN WILL CONTINUE TO WEAKEN THIS EVENING. THEN...
WEAK RIDGE BUILDS INTO EASTERN WISCONSIN AFTER MIDNIGHT TONIGHT
INTO SUNDAY MORNING. DRY WEATHER CONDITIONS ARE EXPECTED AFTER 06Z
TO AROUND 18Z SUNDAY. THE 28.12Z GFS/NAM/ECMWF ARE MORE PROGRESSIVE
WITH SHORTWAVE ROTATING AROUND UPPER LEVEL LOW INTO THE FORECAST
AREA. THE 28.12Z GFS/NAM SHOW DECENT ISENTROPIC LIFT AT 305K
SURFACE...MOISTURE TRANSPORT AND CONVERGENCE AT 925-850MB LAYER...
IN ASSOCIATION WITH THE SHORTWAVE TROUGH. HAVE INCREASED
PRECIPITATION CHANCES FROM 18Z SUNDAY TO 12Z MONDAY. THE 28.12Z
GFS/NAM SHOW AROUND 100 J/KG 0-6KM MOST UNSTABLE CAPE ACROSS
NORTHEAST IOWA AND SOUTHWEST WISCONSIN...INTRODUCED ISOLATED THUNDER
ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN AFTER 18Z SUNDAY. WITH
THE MODELS INDICATING A FASTER SOLUTION WITH THE SHORTWAVE TROUGH...
EXPECT MUCH OF THE PRECIPITATION TO BE EAST OF THE FORECAST AREA BY
18Z MONDAY.
NEXT FORECAST CONCERN IS THE 28.12Z GFS/NAM DEVELOPING SOUTHWESTERLY
FLOW ALOFT OVER ROCKY MOUNTAINS AND UPPER MIDWEST MONDAY NIGHT INTO
TUESDAY. THE DETERMINISTIC MODELS ARE ADVECTING WARMER AIR INTO THE
FORECAST AREA WITH 850MB TEMPERATURES RISING TO PLUS 12 TO PLUS 15
DEGREES CELSIUS BY 00Z WEDNESDAY. HIGH TEMPERATURES TUESDAY WILL BE
MAINLY IN THE LOWER TO MIDDLE 70S...WITH THE POSSIBILITY OF 80
DEGREES OVER NORTHEAST IOWA OR SOUTHEAST MINNESOTA. THE 28.12Z
GFS/NAM DO SHOW MOISTURE TRANSPORT AND ISENTROPIC LIFT AT 305K
SURFACE...MAINLY AFTER 18Z TUESDAY ACROSS THE FORECAST AREA. THE
28.12Z GFS/NAM INDICATE DECENT 0-3KM SHEAR AND INSTABILITY DURING
THE DAY TUESDAY. HOWEVER...THE BEST LIFT AND CONVERGENCE AT THIS TIME
APPEARS TO BE NORTHWEST AND SOUTHWEST OF FORECAST AREA AND HAVE KEPT
SMALL CHANCES OF PRECIPITATION ACROSS FORECAST AREA.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
315 PM CDT SAT APR 28 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES THROUGH THE
PERIOD AND UNSEASONABLY WARM TEMPERATURES THROUGH THURSDAY. THE
28.12Z GFS/GEM/ECMWF CONTINUE TO DEVELOP WEST TO SOUTHWESTERLY FLOW
ALOFT AND CONTINUE TO HAVE DIFFERENCES IN TIMING OF SHORTWAVE
TROUGHS EMBEDDED IN THE WEST TO SOUTHWESTERLY FLOW ALOFT THROUGH
THE PERIOD. CONFIDENCE IN TIMING OF THE INDIVIDUAL SHORTWAVE TROUGHS
MOVING INTO THE UPPER GREAT LAKES REGION IS LOW...HOWEVER
CONFIDENCE IS INCREASING AN ACTIVE WEATHER PATTERN WILL SET UP OVER
THE UPPER GREAT LAKES AND UPPER MIDWEST REGION MIDDLE OF NEXT WEEK.
THE DETERMINISTIC 28.12Z GFS/GEM/ECMWF SHOW WARM AIR ADVECTING INTO
THE FORECAST AREA TUESDAY NIGHT AND CONTINUING INTO THURSDAY...WITH
850MB TEMPERATURES RANGING FROM PLUS TWELVE DEGREES CELSIUS TO
PLUS FIFTEEN DEGREES CELSIUS AND THE 28.00Z GEFS INDICATING
STANDARD ANOMALIES OF 1-1.5. EXPECT TEMPERATURES TO BE
WELL ABOVE NORMAL THROUGH THE MIDDLE OF NEXT WEEK ACROSS FORECAST
AREA.
&&
.AVIATION...THROUGH 18Z SUNDAY
1239 PM CDT SAT APR 28 2012
THE 800 TO 600 MB FRONTOGENESIS WILL GRADUALLY WEAKEN THIS
AFTERNOON. AS THIS OCCURS...THE RAIN WILL DISSIPATE AT BOTH TAF
SITES AROUND 28.21Z. ONCE THE RAIN ENDS...THE CEILINGS WILL BECOME
IFR AT KRST AND MVFR AT KLSE. AS EASTERLY WINDS BRING DRIER AIR
INTO WESTERN WISCONSIN LATE THIS EVENING...THE CEILINGS WILL
GRADUALLY RISE INTO THE 3500 TO 4500 FEET RANGE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
315 PM CDT SAT APR 28 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION.....BOYNE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1123 AM CDT SAT APR 28 2012
.UPDATE...
NAM SHOWS 700 MB RH GRADUALLY DRYING THIS AFTERNOON AS 700 MB
UPWARD MOTION ENDS AND 850/700 MB MOISTURE CONVERGENCE WEAKENS. THE
DRYING FROM THE NORTHEAST BEGINS. AS A RESULT EXPECT THE BAND OF
RAIN TO ERODE FROM THE NORTHEAST AND ALSO DIMINISH AS THE FORCING WEAKENS.
STILL HIGH 850 MB RH SO CLOUDS WILL PERSIST THIS AFTERNOON.
&&
.AVIATION/18Z TAFS/...
MVFR/IFR CIGS MAINLY SOUTHWEST OF MADISON..AND IN THE MODERATE
RAIN BAND NORTH OF MADISON. ELSEWHERE MAINLY VFR CIGS BUT SCATTERED
8 HUNDRED TO 15 HUNDRED FOOT STRATOFRACTUS CLOUDS ARE EXPECTED TO
INCREASE A BIT BRINGING MORE MVFR/IFR CIGS THIS AFTERNOON.
BAND OF RAIN IS EXPECTED TO DIMINISH THIS AFTERNOON AND DRYING
FROM THE NORTHEAST WILL INCREASE TONIGHT AS THE HIGH PRESSURE
CENTERED OVER HUDSON BAY RE-ESTABLISHES ITSELF OVER THE GREAT
LAKES ON SUNDAY.
HOWEVER AREAS SOUTHWEST OF MADISON WILL REMAIN MOIST AND MVFR/IFR
CIGS WILL LINGER OVERNIGHT.
&&
.PREV DISCUSSION... /ISSUED 334 AM CDT SAT APR 28 2012/
SHORT TERM....TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
LINGERING DRY AIR OVER SRN WI RESULTING IN EVAPORATIVE COOLING AND
AREAS OF SLEET AND EVEN SOME SNOWFLAKES MIXED IN WITH THE LIGHT RAIN
EARLY THIS MORNING. LATEST RUC SOUNDINGS SHOW WET BULB ZERO
REMAINING NEAR OR SLIGHTLY BELOW FREEZING FOR A TIME EARLY THIS
MORNING UNTIL SATURATION OCCURS BETWEEN 10Z AND 15Z. BURST OF
STRONG Q-VECTOR CONVERGENCE AND IMPRESSIVE FN VECTOR RESPONSE TO
FRONTOGENESIS PUSHES IN DURING THIS TIME AS LOW LEVEL SATURATION
OCCURS. SFC TEMPS SHOULD REMAIN ABV FREEZING AS PRECIP SPREADS OVER
THE AREA...BUT NOT IMPOSSIBLE A BURST OF SLEET OR SNOW RESULTS IN
SOME MINOR ACCUMULATION ON GRASS EARLY THIS MRNG. WL NEED TO WATCH
THIS CLOSELY AND ISSUE FREQUENT SHORT TERM FORECASTS.
OTHERWISE...LOW LEVELS EXPECTED TO WARM AND SATURATE THIS MRNG AS
STRONG FORCING ASSOCIATED WITH VIGOROUS MID LEVEL SHORT WAVE OVER
IOWA PUSHES INTO SOUTHERN WI. IMPRESSIVE FN VECTOR RESPONSE TO
LAYER FRONTOGENESIS THIS MRNG WITH 10 TO 20 UNITS OF Q-VECTOR
CONVERGENCE. SHORT WAVE LOSES ITS VIGOR LATE THIS MRNG AND AFTN AS
IT RUNS INTO BUILDING MID LEVEL HIGH PRESSURE OVER THE WESTERN
GTLAKES AND THE CONTINUOUS FEED OF DRIER AIR. LINGERING WEAKENING
FORCING AND DEFORMATION WL RESULT IN AREAS OF -RA CONTINUING INTO
THE AFTN...BUT INTENSITY AND SPACIAL COVERAGE SHOULD BE SLOWLY
DIMINISHING. GRADUAL CLEARING IN THE NORTHERN CWA TONIGHT WL ALLOW
TEMPS TO FALL INTO THE LOW 30S WITH FROST POSSIBLE LATE.
LONG TERM...SUNDAY...FORECAST CONFIDENCE HIGH.
MODELS IN GOOD AGREEMENT THAT SUFACE HIGH CENTERED NORTH OF GREAT
LAKES SUNDAY WILL DOMINATE THE REGION AND LIMIT CLOUDS AND KEEP
REGION DRY. LAKE MICHIGAN WATER TEMPS ARE MIDDLE TO UPPER 40S SO
EAST WINDS OFF LAKE MICHIGAN SUNDAY AND WILL KEEP SUNDAY HIGH TEMPS
NEAR 50 ALONG LAKESHORE TO UPPER 50S IN SOUTHCENTRAL AND SOUTHWEST
WISCONSIN.
SUNDAY NIGHT THROUGH MONDAY NIGHT...FORCAST CONFIDENCE HIGH FOR
PRECIP CHANCES AND TYPE...MEDIUM FOR TIMING START AND END TIMES.
MODELS IN GOOD AGREEMENT MOVING SURFACE HIGH EAST OF THE AREA SUNDAY
NIGHT AND MONDAY WITH SOUTHERLY LOW LEVEL RETURN FLOW AND
APPROACHING UPPER LEVEL TROUGH BRINGING WARMER TEMPERTURES ALONG
WITH MOISTURE AND CLOUDS TO THE REGION SUNDAY NIGHT AND MONDAY. SOME
DISAGREEMENT ON TIMING OF START AND END OF PRECIPITATION...WITH NAM
SLOWER THAN EUROPEAN UKMET AND GFS WHICH START PRECIPITATION IN
SOUTHWEST WISCONSIN AROUND SUNDOWN SUNDAY AND MOVE AND INTENSIFY IT
ACROSS MOST OF THE STATE BY SUNRISE MONDAY AND CONINUE IT THROUGH
THE DAY MONDAY. PRECIPITATION DISSIPATES WEST TO EAST MONDAY NIGHT.
TEMPERATURES WARM ENOUGH THAT ALL PRECIPITATION WILL BE LIQUID WITH
HIGHEST PRECIPITATION AMOUNTS SOUTH OF I-94.
TUESDAY THROUGH SATURDAY. FORECAST CONFIDENCE MEDIUM.
SURFACE LOW OVER DAKOTAS AND MINNESOTA TUESDAY AND WEDNESDAY WILL
KEEP SOUTHERLY WINDS AND WARM TEMPERATURES...WITH HIGHS NEAR 70
TUESDAY AND MID 70S WEDNESDAY AND THURSDAY. UPPER TROUGH WEST OF THE
REGION WILL ALLOW SOUTHWEST FLOW WITH UPPER LEVEL DISTURBANCES
MOVING IN SOUTHWEST FLOW ACROSS THE REGION AND BRINGING CHANCE OF
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH SATURDAY. BEST CHANCE OF
STRONG THUNDERSTORMS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH BEST
CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WHEN CAPE...BULK SHEAR
AND OTHER SEVERE INDICIES ARE AT A MAXIMUM FOR THE ENTIRE WEEK.
ADDITIONAL UPPER SHORT WAVES WILL CONTINUE UNSETTLED WEATHER THROUGH
SATURDAY WHEN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE REGION.
AVIATION/12Z TAFS/...NOT IMPOSSIBLE A BURST OF MODERATE SLEET OR
EVEN SNOW COULD BRIEFLY AFFECT TAF SITES EARLY THIS MORNING AS
STRONG FORCING WITH APPROACHING SHORT WAVE MOVES INTO SOUTHERN WI.
LINGERING DRY AIR RESULTING IN EVAPORATIVE COOLING AND MIX OF
PRECIP...SHOULD MOISTEN UP THIS MRNG...WITH PERIODS OF RA EXPCD
FOR MOST OF THE DAY. ONLY A LITTLE DRIZZLE POSSIBLE FOR A TIME
THIS EVENING DUE TO LINGERING MID-LEVEL DEFORMATION. CIGS SHOULD
LOWER TO IFR AND POSSIBLY LWR LATER THIS MORNING...GRADUALLY
LIFTING LATE TODAY AND TNGT.
MARINE...PRESSURE GRADIENT CONTINUES TO TIGHTEN OVER SOUTHERN LAKE
MI THIS MORNING AS LOW PRESSURE MOVES ACROSS NRN MO. GRADIENT WL
BEGIN TO RELAX LATER TODAY AND TONIGHT AS LOW WEAKENS TO THE
SOUTH...AND HIGH PRESSURE RIDGE BUILDS IN FROM THE NORTH. LOW LEVEL
UNSTABLE AIR MASS OVER THE LAKE SHOULD RESULT IN WINDS UP TO 30KTS
IN SRN MARINE ZONE...TRAILING OFF THE NORTH. WL CONTINUE SMALL
CRAFT ADVISORY FOR SRN 3 ZONES FOR TODAY AND TNGT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 4 AM CDT SUNDAY FOR LMZ644>646.
&&
$$
UPDATE...HENTZ
TODAY/TONIGHT AND AVIATION/MARINE...MBK
SUNDAY THROUGH FRIDAY...SLB
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
334 AM CDT SAT APR 28 2012
.SHORT TERM....TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
LINGERING DRY AIR OVER SRN WI RESULTING IN EVAPORATIVE COOLING AND
AREAS OF SLEET AND EVEN SOME SNOWFLAKES MIXED IN WITH THE LIGHT RAIN
EARLY THIS MORNING. LATEST RUC SOUNDINGS SHOW WET BULB ZERO
REMAINING NEAR OR SLIGHTLY BELOW FREEZING FOR A TIME EARLY THIS
MORNING UNTIL SATURATION OCCURS BETWEEN 10Z AND 15Z. BURST OF
STRONG Q-VECTOR CONVERGENCE AND IMPRESSIVE FN VECTOR RESPONSE TO
FRONTOGENESIS PUSHES IN DURING THIS TIME AS LOW LEVEL SATURATION
OCCURS. SFC TEMPS SHOULD REMAIN ABV FREEZING AS PRECIP SPREADS OVER
THE AREA...BUT NOT IMPOSSIBLE A BURST OF SLEET OR SNOW RESULTS IN
SOME MINOR ACCUMULATION ON GRASS EARLY THIS MRNG. WL NEED TO WATCH
THIS CLOSELY AND ISSUE FREQUENT SHORT TERM FORECASTS.
OTHERWISE...LOW LEVELS EXPECTED TO WARM AND SATURATE THIS MRNG AS
STRONG FORCING ASSOCIATED WITH VIGOROUS MID LEVEL SHORT WAVE OVER
IOWA PUSHES INTO SOUTHERN WI. IMPRESSIVE FN VECTOR RESPONSE TO
LAYER FRONTOGENESIS THIS MRNG WITH 10 TO 20 UNITS OF Q-VECTOR
CONVERGENCE. SHORT WAVE LOSES ITS VIGOR LATE THIS MRNG AND AFTN AS
IT RUNS INTO BUILDING MID LEVEL HIGH PRESSURE OVER THE WESTERN
GTLAKES AND THE CONTINUOUS FEED OF DRIER AIR. LINGERING WEAKENING
FORCING AND DEFORMATION WL RESULT IN AREAS OF -RA CONTINUING INTO
THE AFTN...BUT INTENSITY AND SPACIAL COVERAGE SHOULD BE SLOWLY
DIMINISHING. GRADUAL CLEARING IN THE NORTHERN CWA TONIGHT WL ALLOW
TEMPS TO FALL INTO THE LOW 30S WITH FROST POSSIBLE LATE.
.LONG TERM...SUNDAY...FORECAST CONFIDENCE HIGH.
MODELS IN GOOD AGREEMENT THAT SUFACE HIGH CENTERED NORTH OF GREAT
LAKES SUNDAY WILL DOMINATE THE REGION AND LIMIT CLOUDS AND KEEP
REGION DRY. LAKE MICHIGAN WATER TEMPS ARE MIDDLE TO UPPER 40S SO
EAST WINDS OFF LAKE MICHIGAN SUNDAY AND WILL KEEP SUNDAY HIGH TEMPS
NEAR 50 ALONG LAKESHORE TO UPPER 50S IN SOUTHCENTRAL AND SOUTHWEST
WISCONSIN.
SUNDAY NIGHT THROUGH MONDAY NIGHT...FORCAST CONFIDENCE HIGH FOR
PRECIP CHANCES AND TYPE...MEDIUM FOR TIMING START AND END TIMES.
MODELS IN GOOD AGREEMENT MOVING SURFACE HIGH EAST OF THE AREA SUNDAY
NIGHT AND MONDAY WITH SOUTHERLY LOW LEVEL RETURN FLOW AND
APPROACHING UPPER LEVEL TROUGH BRINGING WARMER TEMPERTURES ALONG
WITH MOISTURE AND CLOUDS TO THE REGION SUNDAY NIGHT AND MONDAY. SOME
DISAGREEMENT ON TIMING OF START AND END OF PRECIPITATION...WITH NAM
SLOWER THAN EUROPEAN UKMET AND GFS WHICH START PRECIPITATION IN
SOUTHWEST WISCONSIN AROUND SUNDOWN SUNDAY AND MOVE AND INTENSIFY IT
ACROSS MOST OF THE STATE BY SUNRISE MONDAY AND CONINUE IT THROUGH
THE DAY MONDAY. PRECIPITATION DISSIPATES WEST TO EAST MONDAY NIGHT.
TEMPERATURES WARM ENOUGH THAT ALL PRECIPITATION WILL BE LIQUID WITH
HIGHEST PRECIPITATION AMOUNTS SOUTH OF I-94.
TUESDAY THROUGH SATURDAY. FORECAST CONFIDENCE MEDIUM.
SURFACE LOW OVER DAKOTAS AND MINNESOTA TUESDAY AND WEDNESDAY WILL
KEEP SOUTHERLY WINDS AND WARM TEMPERATURES...WITH HIGHS NEAR 70
TUESDAY AND MID 70S WEDNESDAY AND THURSDAY. UPPER TROUGH WEST OF THE
REGION WILL ALLOW SOUTHWEST FLOW WITH UPPER LEVEL DISTURBANCES
MOVING IN SOUTHWEST FLOW ACROSS THE REGION AND BRINGING CHANCE OF
SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH SATURDAY. BEST CHANCE OF
STRONG THUNDERSTORMS TUESDAY NIGHT THROUGH WEDNESDAY NIGHT WITH BEST
CHANCE OF SEVERE WEATHER WEDNESDAY AFTERNOON WHEN CAPE...BULK SHEAR
AND OTHER SEVERE INDICIES ARE AT A MAXIMUM FOR THE ENTIRE WEEK.
ADDITIONAL UPPER SHORT WAVES WILL CONTINUE UNSETTLED WEATHER THROUGH
SATURDAY WHEN UPPER LEVEL RIDGE STARTS TO BUILD OVER THE REGION.
&&
.AVIATION/12Z TAFS/...NOT IMPOSSIBLE A BURST OF MODERATE SLEET OR
EVEN SNOW COULD BRIEFLY AFFECT TAF SITES EARLY THIS MORNING AS
STRONG FORCING WITH APPROACHING SHORT WAVE MOVES INTO SOUTHERN WI.
LINGERING DRY AIR RESULTING IN EVAPORATIVE COOLING AND MIX OF
PRECIP...SHOULD MOISTEN UP THIS MRNG...WITH PERIODS OF RA EXPCD
FOR MOST OF THE DAY. ONLY A LITTLE DRIZZLE POSSIBLE FOR A TIME
THIS EVENING DUE TO LINGERING MID-LEVEL DEFORMATION. CIGS SHOULD
LOWER TO IFR AND POSSIBLY LWR LATER THIS MORNING...GRADUALLY
LIFTING LATE TODAY AND TNGT.
&&
.MARINE...PRESSURE GRADIENT CONTINUES TO TIGHTEN OVER SOUTHERN LAKE
MI THIS MORNING AS LOW PRESSURE MOVES ACROSS NRN MO. GRADIENT WL
BEGIN TO RELAX LATER TODAY AND TONIGHT AS LOW WEAKENS TO THE
SOUTH...AND HIGH PRESSURE RIDGE BUILDS IN FROM THE NORTH. LOW LEVEL
UNSTABLE AIR MASS OVER THE LAKE SHOULD RESULT IN WINDS UP TO 30KTS
IN SRN MARINE ZONE...TRAILING OFF THE NORTH. WL CONTINUE SMALL
CRAFT ADVISORY FOR SRN 3 ZONES FOR TODAY AND TNGT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY FROM 7 AM THIS MORNING TO 4 AM CDT SUNDAY
FOR LMZ644>646.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
SUNDAY THROUGH FRIDAY...SLB
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
908 PM MDT SUN APR 29 2012
.UPDATE...EVENING WATER VAPOR IMAGERY SHOWED UPPER LEVEL SHORTWAVE
INTO WEST CENTRAL NEBRASKA AND EASTERN COLORADO. ISOLATED TSTORMS
CONTINUED TO DEVELOP ALONG THIS WAVE...WITH DRIER MORE STABLE
SUBSIDENT FLOW IN ITS WAKE THROUGHOUT THE CWA. HENCE...THE REST
OF THIS EVENING WILL BE DRY WITH CLEARING SKIES. THE OVERNIGHT
LOW TEMPERATURE FORECAST IS ON TRACK. GUSTY WEST TO SOUTHWEST
WINDS ALONG AND WEST OF THE LARAMIE RANGE HAVE DECREASED. EXPECT
LIGHT AND VARIABLE WINDS FOR TONIGHT. 00Z NAM AND HRRR ADVECT SOME
LOW LEVEL MOISTURE FROM SOUTHERLY BOUNDARY LAYER FLOW INTO THE
SOUTHERN NEBRASKA PANHANDLE AFTER MIDNIGHT. THIS WILL RESULT
IN PATCHY FOG AND LOW STRATUS.
&&
.PREV DISCUSSION... /ISSUED 608 PM MDT SUN APR 29 2012/
UPDATE...
AVIATION...00Z TAF ISSUANCE...A FEW SHOWERS REMAIN POSSIBLE OVER
THE FAR EASTERN PANHANDLE FROM KAIA TO KSNY THROUGH 02Z THIS
EVENING. BREEZY WESTERLY WINDS OCCURRING ACROSS MUCH OF THE AREA
WILL DIMINISH OVERNIGHT. AFTER 06Z...IFR CEILINGS AND VISIBILITIES
IN FOG CAN BE EXPECTED OVER PARTS OF THE SOUTHERN PANHANDLE
ESPECIALLY AT KSNY THROUGH 15Z. MODERATE SOUTHWEST SURFACE WINDS
WILL RETURN ALONG AND WEST OF THE LARAMIE RANGE LATE MONDAY
MORNING WITH GUSTS UP TO 40 KT IN THIS AREA EXPECTED THROUGH 01Z
TUESDAY. RJM
PREV DISCUSSION... /ISSUED 318 PM MDT SUN APR 29 2012/
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...VISIBLE SATELLITE
IMAGERY SHOWS A LOT OF FLAT CUMULUS OVER THE CWA IN THE STABLE AIR
BEHIND THE SHORTWAVE TROUGH AXIS CURRENTLY OVER THE NEBRASKA
PANHANDLE. LEFT A SLIGHT CHANCE OF TSTMS FOR CHEYENNE COUNTY
THROUGH THE EARLY EVENING AS THE CURRENT LAPS ANALYSIS SHOWS
100-200 J/KG OF CAPE OVER THE SOUTHERN NEBRASKA PANHANDLE...HOWEVER
THE SUBSIDENCE BEHIND THE SHORTWAVE IS QUICKLY MOVING EASTWARD.
THE REST OF THE SHORT TERM WILL FEATURE INCREASING WESTERLY WINDS
AND WARMER TEMPS ON MON AND TUES. MID LEVEL FLOW WILL BECOME MORE
ZONAL ON MONDAY WITH STRENGTHENING 700MB FLOW...ESPECIALLY DURING
THE AFTN. WESTERLY WINDS ALONG AND WEST OF THE LARAMIE RANGE WILL
BECOME BREEZY TO WINDY DURING THE AFTN UNDER 35 KT OF 700MB FLOW.
WILL ALSO SEE A WARMING TREND FROM THIS PAST WEEKEND...WITH
WIDESPREAD TEMPS IN THE 70S OVER THE PLAINS...AS 700MB TEMPS RISE
TO AROUND 7C. A LEE TROUGH WILL MAINTAIN DOWNSLOPING OVER THE
PLAINS THROUGH TUES IN ADVANCE OF A SHORTWAVE MOVING THROUGH THE
NORTHERN INTERMOUNTAIN WEST. THE LIFT FROM THIS SHORTWAVE WILL
CAUSE INCREASING CHANCES OF SHOWERS AND ISOLATED TSTMS ON TUES
AFTN...MAINLY ALONG AND WEST OF THE LARAMIE RANGE. COULD HAVE SOME
HIGH BASED TSTMS MOVE OVER THE PLAINS...HOWEVER LLVL MOISTURE AND
INSTABILITY IS LACKING DUE TO THE WESTERLY BOUNDARY LAYER FLOW. AS
THE SHORTWAVE MOVES ACROSS NORTHEAST MT ON TUES NIGHT...700MB
TEMPS DECREASE TO 0-1C OVER THE WESTERN PART OF THE CWA. THIS
MEANS A FEW SNOW SHOWERS COULD FALL OVER THE HIGHER ELEVATIONS OF
THE SIERRA MADRE/SNOWY RANGE IN THE LINGERING MOIST 700-500MB
FLOW.
LONG TERM...WEDNESDAY THROUGH SUNDAY...THIS PART OF THE FORECAST
WILL CONTINUE WITH TEMPERATURES ABOVE NORMAL THROUGH AT LEAST THE
EARLY PART OF NEXT WEEKEND. THERE WILL ALSO BE AT LEAST A SMALL
THREAT OF ALMOST DAILY SHOWERS AND LATE DAY THUNDERSTORMS. HEIGHTS
ALOFT SLOWLY RISE AND FLOW SLOWLY BACKS OVER THE ROCKIES THROUGH
SATURDAY. THE FAIRLY FLAT AND PROGRESSIVE FLOW ALOFT WILL BECOME
MORE AMPLIFIED THROUGH NEXT WEEKEND. A DEEP TROUGH DEVELOPS ALONG
THE WEST COAST LATE IN THE WEEK WITH AN UPPER LOW EVENTUALLY
CLOSING OFF ON SATURDAY OVER NORTHERN CALIFORNIA. MODELS DIFFER IN
THE PLACEMENT OF THE TROUGH AND UPPER LOW OVER THE WEEKEND. THE
ECMWF HAS BEEN SLOWER THAN THE GFS DURING THAT TIME...BUT THE 12Z
ECMWF IS FASTER WITH THE LARGE UPPER LOW OVER IDAHO 12Z SUNDAY.
WILL CONTINUE TO LEAN MORE TOWARDS THE SLOWER AND DEEPER 00Z ECMWF
PLACEMENT FOR THIS FORECAST. SHORTWAVE TROUGHS WITHIN THE FLOW
ALOFT WILL MOVE ACROSS THE REGION THROUGH SATURDAY WITH THE ECMWF
CONTINUING TO MOVE AN OLD UPPER LOW TO THE NORTHEAST AND OVER THE
CWA SATURDAY AND SATURDAY NIGHT. THE SHORTWAVE TROUGHS WILL MOVE
SEVERAL SURFACE BOUNDARIES ACROSS THE CWA THROUGH THIS PERIOD. THE
BOUNDARIES...SHORTWAVE TROUGHS AND FAVORABLE 300 MB JET LOCATIONS
AT TIMES WILL PRODUCE THE SHOWERS AND LATE DAY STORMS OVER
PORTIONS OF THE CWA. THE MODELS...ESPECIALLY THE ECMWF...DRY THE
ATMOSPHERE OVER THE CWA SOME ON THURSDAY AND EVEN MORE SO FOR
FRIDAY. FOR NOW WILL TRY TO DIFFERENTIATE THE BETTER PERIODS FOR
PRECIPITATION FROM THE PERIODS THAT CURRENTLY DO NOT LOOK AS
FAVORABLE. SO WILL HAVE THE HIGHEST POPS OVER THE CWA WEDNESDAY
AFTERNOON AND EARLY NIGHT AND A MINIMUM FOR FRIDAY. POPS WILL
AGAIN INCREASE OVER THE REGION FOR NEXT WEEKEND AS MOISTURE AND
INSTABILITY INCREASE AHEAD OF THE UPSTREAM STORM SYSTEM. SATURDAY
AFTERNOON AND EVENING MAY BE A POTENTIAL SEVERE WEATHER DAY...WITH
NEXT SUNDAY COOLER AND SHOWERY.
&&
FIRE WEATHER...THE RECENT RAINFALL OVER THE PAST WEEK ACROSS
SOUTHEAST WYOMING AND NEBRASKA PANHANDLE IS CONTRIBUTING TO A
GREEN UP OVER MOST OF THE AREA. THERE IS AN ELEVATED FIRE DANGER
THREAT ON MONDAY AFTERNOON DUE TO THE COMBINATION OF WARM AND DRY
CONDITIONS AND INCREASING WEST TO SOUTHWEST WINDS. MINIMUM
AFTERNOON RELATIVE HUMIDITIES WILL BE AROUND 15 PERCENT OVER
SOUTHEAST WYOMING TO THE EAST OF THE LARAMIE RANGE. THE NEBRASKA
PANHANDLE WILL SEE AFTERNOON HUMIDITY VALUES IN THE 15 TO 20
PERCENT RANGE. WITH A LEE TROUGH DEVELOPING OVER THE
PLAINS...WESTERLY WINDS WILL INCREASE TO 15 TO 20 MPH WITH GUSTS
TO 30 MPH...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE. WHILE
THE WEATHER CONDITIONS WARRANT AN ELEVATED FIRE DANGER THREAT...IT
WILL BE TEMPERED BY THE RECENT GREEN UP.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...JAMSKI
AVIATION...RJM
LONG TERM...WEILAND
FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
357 AM EDT MON APR 30 2012
.DISCUSSION...
WATER VAPOR IMAGERY FROM EARLY THIS MORNING SHOWED DRY AIR HAD
WRAPPED INTO THE MID/UPPER LOW LOCATED OVER SOUTH FLORIDA. THIS HAS
PREVENTED THE HEAVY RAIN THAT WAS EXPECTED ACROSS THE REGION
OVERNIGHT...AND INSTEAD LIGHT TO MODERATE SHOWERS WERE MOVING ACROSS
SOUTH FLORIDA. MOST MODEL GUIDANCE HAS BEEN EXTREMELY
INCONSISTENT...FLIPPING BACK AND FORTH EVEN IN THE VERY SHORT TERM.
COMPLETELY TOSSED OUT THE 00Z GFS AS IT IS SUFFERING FROM CONVECTIVE
FEEDBACK. IT HAS A BLOWUP NEAR NAPLES IN THE NEXT COUPLE
HOURS...WHICH STEALS ALL THE MOISTURE FROM THE ATLANTIC.
THE HRRR SHOWS THE AREA OF HEAVIER RAIN THAT WAS DEVELOPING TO THE
EAST SOUTHEAST OF THE KEYS POSSIBLY MOVING NORTHWARD INTO MIAMI DADE
COUNTY OVER THE NEXT SEVERAL HOURS AND THEN MOVING TO THE WEST AND
OUT OF THE REGION AN HOUR OR TWO AFTER SUNRISE. THE MODEL SHOWS THAT
IS PRETTY MUCH THE ENTIRE BALL GAME...WITH EVERYTHING BASICALLY
DISSIPATING AFTER THAT AND ONLY LIGHT TO MODERATE RAIN THROUGHOUT
THE DAY. THIS SCENARIO IS DEFINITELY POSSIBLE...MUCH LIKE WHAT
HAPPENED YESTERDAY. HOWEVER...IN THEORY...WITH THE UPPER LOW
RETROGRADING TO THE WEST AND THE INVERTED TROUGH MOVING TO THE
WEST ACROSS THE REGION...THE CHANCES FOR HEAVIER RAIN SHOULD
ACTUALLY BE BETTER TODAY THAN YESTERDAY. THE ECMWF FOLLOWS THIS
SCENARIO...WITH HEAVIER RAIN MOVING INTO THE COASTLINE BETWEEN 12
AND 18Z AND THEN CONTINUING THROUGH MUCH OF THE DAY. SO ANOTHER
1-3 INCHES OF RAIN IS EXPECTED ALONG THE COAST TODAY...WITH
LOCALLY HIGHER AMOUNTS. THOUGHT ABOUT DROPPING THE FLOOD WATCH
FOR PALM BEACH COUNTY AS MOST OF THE HEAVY RAIN SHOULD BE ACROSS
BROWARD AND MIAMI DADE COUNTY. HOWEVER...SINCE GUIDANCE HAS BEEN
INCONSISTENT AT BEST AND THE SOUTHEAST PORTION OF PALM BEACH
COUNTY COULD RECEIVE HEAVY RAIN...LEFT THE FLOOD WATCH IN PLACE.
BREEZY TO WINDY CONDITIONS ARE EXPECTED TODAY...ESPECIALLY TOWARDS
THE EAST COAST...WITH WINDS GUSTING TO 25-35 MPH THROUGH THE DAY. IF
THERE ARE ANY HEAVIER SHOWERS OR THUNDERSTORMS...WIND GUSTS UP TO 50
MPH WILL BE POSSIBLE. UNDERCUT GUIDANCE FOR HIGH TEMPERATURES TODAY
BY 2 TO 8 DEGREES ACROSS THE REGION...CUTTING TEMPS THE MOST ACROSS
THE GULF COAST. GUIDANCE TEMPS IN THE LOW TO MID 80S SEEMED
UNREASONABLE FOR NAPLES DUE TO THE CLOUD COVER AND RAINFALL
EXPECTED TODAY...AND TEMPERATURES MAY ACTUALLY NOT RISE OUT OF THE
LOWER 70S. ACROSS MOST OF THE REGION...TEMPERATURES MORE THAN
LIKELY WILL NOT CHANGE BY MORE THAN A COUPLE DEGREES FROM WHAT
WILL BE OBSERVED THIS MORNING.
THE SHARP INVERTED TROUGH IS EXPECTED TO MOVE WELL OUT INTO THE GULF
OVERNIGHT TONIGHT...BUT ONSHORE FLOW AND A STREAM OF DEEP MOISTURE
WILL STAY OVER THE REGION AS HIGH PRESSURE HOLDS STEADY OVER THE
WESTERN ATLANTIC. WITH A RELATIVELY TIGHT GRADIENT
REMAINING...SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED ALONG THE
EAST COAST AND DEEP SOUTH FLORIDA. HIGH PRESSURE IS EXPECTED TO
REMAIN OVER THE WESTERN ATLANTIC THROUGH MIDWEEK...WITH AROUND 20
KNOT WINDS CONTINUING OVER THE LOCAL ATLANTIC WATERS. SO AT LEAST
SCATTERED SHOWERS WILL CONTINUE...ESPECIALLY IN THE OVERNIGHT
HOURS DUE TO THE SPEED SHEAR ALONG THE COAST. HIGH PRESSURE IS
EXPECTED TO WEAKEN THURSDAY INTO THE WEEKEND...AND RAIN CHANCES
ARE EXPECTED TO SLOWLY DECREASE THROUGH THIS PERIOD. AS THE RAIN
CHANCES DECREASE...TEMPERATURES WILL WARM BACK INTO THE 80S TO
AROUND 90 ACROSS THE NORTHWEST INTERIOR.
&&
.AVIATION...
06Z ISSUANCE...A SURFACE TROUGH OF LOW PRESSURE CONTINUES TO MOVE
SLOWLY WEST NEAR THE SOUTHEAST FLORIDA COAST. MEANWHILE, THE
ASSOCIATED MID LEVEL LOW IS LOCATED OVER FAR SOUTH FLORIDA. WITH
PERSISTENT AND STRONG EASTERLY FLOW CONTINUING, WE EXPECT
SCATTERED TO NUMEROUS SHOWERS TO PREVAIL, ALONG WITH PERHAPS A FEW
TSRA AS WELL. TEMPO GROUPS TO INDICATE MVFR CEILINGS ARE
WARRANTED, ALTHOUGH EVEN IFR CONDITIONS COULD BRIEFLY OCCUR IN
HEAVIER SHRA. EASTERLY WINDS WILL PERSIST THROUGH THE TAF PERIOD.
SUSTAINED SURFACE WINDS WILL AVERAGE 15-20 KNOTS WITH FREQUENT
HIGHER GUSTS.
&&
.MARINE...
DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
&&
.FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 73 81 74 / 60 30 30 20
FORT LAUDERDALE 76 73 79 74 / 70 50 40 40
MIAMI 76 73 79 74 / 70 60 50 40
NAPLES 77 70 81 70 / 50 30 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH THIS EVENING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM BEACH.
HIGH RIP CURRENT RISK THROUGH TUESDAY EVENING FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR BISCAYNE BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...84/AK
AVIATION/RADAR...14/MJB
AREA FORECAST DISCUSSION
NWS MIAMI FL
110 AM EDT MON APR 30 2012
.AVIATION...06Z ISSUANCE...A SURFACE TROUGH OF LOW PRESSURE
CONTINUES TO MOVE SLOWLY WEST NEAR THE SOUTHEAST FLORIDA COAST.
MEANWHILE, THE ASSOCIATED MID LEVEL LOW IS LOCATED OVER FAR SOUTH
FLORIDA. WITH PERSISTENT AND STRONG EASTERLY FLOW CONTINUING, WE
EXPECT SCATTERED TO NUMEROUS SHOWERS TO PREVAIL, ALONG WITH
PERHAPS A FEW TSRA AS WELL. TEMPO GROUPS TO INDICATE MVFR
CEILINGS ARE WARRANTED, ALTHOUGH EVEN IFR CONDITIONS COULD
BRIEFLY OCCUR IN HEAVIER SHRA. EASTERLY WINDS WILL PERSIST
THROUGH THE TAF PERIOD. SUSTAINED SURFACE WINDS WILL AVERAGE
15-20 KNOTS WITH FREQUENT HIGHER GUSTS.
&&
.PREV DISCUSSION... /ISSUED 929 PM EDT SUN APR 29 2012/
UPDATE...WINDS ALONG THE ATLANTIC COAST ARE RUNNING A TAD
HIGHER THAN INHERITED FORECAST, SO INCREASED WINDS A BIT THERE.
VIRGINA KEY IS GUSTING TO 37 KT AND FOWEY ROCKS IS NOW SUSTAINED
AT 30 KT, BUT THESE SITES ARE A BIT ELEVATED. EVEN SO, HIGH-END
SMALL CRAFT ADVISORY CONDITIONS WILL BE OCCURRING OFF THE
BROWARD/MIAMI-DADE COAST OVERNIGHT.
THE SOLID RAIN SHIELD ACROSS SE FLORIDA AND THE ATLANTIC SURE
BROKE UP EARLIER THIS EVENING. WATER VAPOR IMAGERY SHOWS THAT
UPPER LEVEL DRY AIR HAS INFILTRATED INTO THE AREA FROM THE SOUTH
AS THE MID LEVEL LOW IS NOW BISECTING THE AREA WITH DRY AIR
WRAPPED INTO IT ON ITS WEST AND SOUTH SIDE. THE UPPER TROUGH AXIS
IS ALIGNED FROM NW TO SE ACROSS SOUTH FL. THIS HAS BROUGHT IN SOME
SUBSIDENCE ON ITS WEST SIDE. THE BIG QUESTION IS WHAT WILL BE THE
TREND OVERNIGHT. GIVEN RADAR TRENDS AND LACK OF APPRECIABLE
ENVIRONMENTAL CHANGES OVERNIGHT...THE CURRENT THINKING IS THAT
PERIODS OF SHOWERS WILL CONTINUE TO MOVE ONSHORE THE SE FL COAST
WITH JUST A SLIGHT CHANCE OF A THUNDERSTORM.
THE PWAT ON THE MIAMI EVENING SOUNDING IS AT 1.87 INCHES, OR 170%
ABOVE AVG AND IN THE 99TH PERCENTILE FOR THIS TIME OF THE YEAR.
SO WITH THAT SAID, SHOULD A BAND OF HEAVY SHOWERS
DEVELOP...LOCALIZED LOCALES COULD SEE HEAVY RAINFALL OVERNIGHT
WITH POTENTIAL FLOODING CONCERNS DEVELOPING. HOWEVER, THIS THREAT
DOES NOT LOOK AS HIGH AS EARLIER THOUGHT, THOUGH STILL POSSIBLE.
SO WILL KEEP THE FLOOD WATCH GOING. ALSO, THE HEAVY RAIN RISK MAY
INCREASE ON MONDAY. KEY WEST AND MIAMI RADAR IMAGERY SHOWS A
CLUSTER OF CONVECTION AND CYCLONIC FLOW SOME 70 NM SE OF MARATHON.
THIS IS AT 8-10K FT. RIGHT NOW NO SIGNS OF A SURFACE CIRCULATION.
THIS FEATURE ASSOCIATED WITH A TROUGH WILL MOVE WEST NORTHWEST
OVERNIGHT-MONDAY PLACING SOUTH FL IN A FAVORABLE ESE MOIST WIND
FLOW FOR POSSIBLE LOCALIZED HEAVY RAINS. /GREGORIA
PREV DISCUSSION... /ISSUED 720 PM EDT SUN APR 29 2012/
AVIATION...SFC TROF XTNDG FM UPR FLA STRAITS NE TO N BAHAMAS
SLOLY MOVG W AND JUST OFF OF THE SE FLA COAST AT 30/12Z. SYSTEM
CROSSES S FLA AND INTO GUF OF MEX BY 30/18Z. VRY MOIST EASTERLY
WND FLOW WL PERSIST ACRS THE AREA THRU PD. ATTM WDSPRD MVFR CIG
ACRS S FLA WITH AREAS OF -RA BUT VSBY VFR. AFT 06Z WDSPRD MVFR CIG
AND -RA CONTINUES BUT POCKETS OF EMBEDDED HVY SHWRS MAY PRODUCE
IFR CIG /VSBY AT TIMES. WILL PLACE TEMPO MVFR CIG/VSBY VALUES IN
TAFS AFT 06Z PENDING DEVELOPMENT. EASTERLY WINDS WL PERSIST ALL
TAF SITES AND ARE XPCTD TO INCRS.
PREV DISCUSSION... /ISSUED 225 PM EDT SUN APR 29 2012/
DISCUSSION...WATER VAPOR CONTINUES TO SHOW WELL DEFINED MID LEVEL
TROUGH OVER THE WESTERN CARIBBEAN EXTENDING NORTHEAST INTO THE FL
STRAITS. AT THE SFC, A BROAD TROUGH ALSO STRETCHES ACROSS ROUGHLY
THE SAME AREA WITH VISIBLE SATELLITE INDICATING BROAD CIRCULATION
AROUND THESE TWO FEATURES WITH A RICH PLUME OF TROPICAL MOISTURE
FEED ACROSS CUBA, FL STRAITS AND S FL. THE 12Z MFL SOUNDING
ALTHOUGH CONTAMINATED BY CONVECTION AT LAUNCH TIME SHOWS THE DEEP
EASTERLY FLOW.
LOOKING AT THE VERY SHORT TERM, THE HRRR WHICH HAS BEEN DOING
REMARKABLY WELL THE PAST COUPLE OF DAYS SHOWS A DECREASING TREND
THROUGH THIS AFTERNOON BUT THEN A REGENERATION OFF THE SE CST AFT
03Z THIS EVENING WHICH IS AT THE END OF ITS CURRENT FCST CYCLE. BOTH
THE GFS AND NAM PERSIST IN SHOWING A DEEPENING SFC TROUGH OVER THE FL
KEYS FROM LATE THIS AFTERNOON INTO THIS EVENING AND MOVING IT WEST
INTO THE SE GULF BY LATE MONDAY. THEY HAVE HOWEVER BOTH SCALED BACK
THE STRENGTH AND NO LONGER SHOW A CLOSED CIRCULATION SO WILL STICK
CLOSER TO THE NAM SPEEDS WHICH IS THE WEAKER OF THE TWO MODELS. THE
LONGER RANGE MODELS STILL DIVERGE AS TO THE EVOLUTION OF THESE
SYSTEMS THROUGH THE NEXT 24 TO 36 HOURS BUT ALL AGREE TO A CERTAIN
DEGREE THAT THE BAND OF MOISTURE WILL MOVE VERY LITTLE THROUGH
THIS TIME FRAME. RAINFALL ACCUMULATION IS ALSO TROUBLESOME WITH
THE NAM NOT SHOWING MUCH AFT 00Z THIS EVENING AND ALTHOUGH THERE
HAS BEEN SOME DECREASE IN THE OVERALL REFLECTIVITY FROM THE
REGIONAL RADARS, THE TROPICAL FEED WILL CONTINUE AND THUS THAT
SOLUTION SEEMS UNREALISTIC. THE GFS SEEMS TO BE SUFFERING FROM
CONVECTIVE FEEDBACK AS IT IS SHOWING A BULLS EYE 12 HOUR TOTAL
ENDING AT 18Z MONDAY OF IN EXCESS OF 8 INCHES ACROSS NORTHERN
MIAMI-DADE COUNTY. OF COURSE, GIVEN THESE HISTORIC PWAT ANOMALIES
FOR LATE APRIL THIS SOLUTION CANNOT BE TOTALLY RULED OUT HOWEVER
AND SOMEWHERE FROM BROWARD TO MIAMI- DADE COUNTIES MAY INDEED APPROACH
8 INCHES OR EVEN SLIGHTLY HIGHER BY LATE MONDAY WITH THE GREATEST
COASTAL CONVERGENCE LIKELY OCCURRING AT LOW LEVELS ALONG AND NEAR
THE SOUTHEAST COAST LATE TONIGHT THROUGH EARLY MONDAY. THE ECMWF
IS A MIDDLE OF THE ROAD APPROACH. SO WITH ALL OF THIS BEING SAID,
THE FLOOD WATCH WILL CONTINUE THROUGH MONDAY EVENING FOR THE EAST
COASTAL REGION.
HIGH PRESSURE WILL REMAIN TO THE NORTHEAST OVER THE WESTERN ATLANTIC
WITH THE PRESSURE GRADIENT REMAINING TIGHT SO STRONG COASTAL
CONVERGENCE MAY AGAIN SET UP MONDAY NIGHT INTO EARLY TUESDAY AS THE
HIGH MOISTURE REMAINS ACROSS THE AREA. THE ECMWF HAS COME MORE IN
LINE WITH THE GFS AND SHOWING THE DEEP MOISTURE REMAINING IN PLACE
THROUGH THE END OF THIS WEEK SO RAIN CHANCES WILL CONTINUE WITH THE
HIGHEST CHANCES FOR THE EAST COAST.
MARINE...DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
FIRE WEATHER...NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL
MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 80 73 82 73 / 60 40 50 40
FORT LAUDERDALE 79 74 83 74 / 70 50 50 40
MIAMI 80 72 83 73 / 70 50 50 40
NAPLES 82 70 86 70 / 50 30 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH THIS EVENING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM BEACH.
HIGH RIP CURRENT RISK THROUGH THIS AFTERNOON FOR COASTAL BROWARD-
COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR BISCAYNE
BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
AVIATION...14/MJB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
355 AM EDT MON APR 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE FAIR WEATHER THROUGH THURSDAY. AN UPPER
LEVEL DISTURBANCE AND INCREASING ATMOSPHERIC MOISTURE MAY PROVIDE A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AREA OF STRATUS ENVELOPING THE COAST AND PEE DEE REGION EARLY
THIS MORNING. GFS/NAM AND RUC MODELS INDICATE LOW CLOUDS MOVING
WESTWARD INTO THE MIDLANDS THOUGH SUNRISE. WILL KEEP MENTION OF
PATCHY FOG IN THE FORECAST...BUT GIVEN LIGHT SOUTHEAST WIND FLOW
...EXPECT MORE STRATUS THAN FOG. LOW CLOUDS/FOG IS EXPECTED TO
CLEAR AROUND MID-MORNING. UPPER LEVEL RIDGING WAS OVER THE REGION
THIS MORNING. SURFACE HIGH PRESSURE STRETCHED FROM EASTERN CANADA
DOWN THE EAST COAST TO THE GULF OF MEXICO. WARM AND DRY FORECAST
EXPECTED TODAY AND TONIGHT AS HIGH PRESSURES REMAINS IN CONTROL.
WENT SLIGHTLY ABOVE MOS GUIDANCE FOR AFTERNOON HIGHS...GIVEN ITS
COOL BIAS PAST FEW DAYS. TEMPERATURE WILL BE ABOVE NORMAL IN THE
MID 80S TO LOWER 90 THIS AFTERNOON. LOWS TONIGHT WILL BE
CONSISTENT IN THE LOW TO MID 60S. EXPECT LATE NIGHT/EARLY MORNING LOW
CLOUDS TO DEVELOP AGAIN TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
THE MID AND UPPER LEVEL RIDGE REMAIN OVER THE REGION THROUGH
THURSDAY NIGHT. THIS ALONG WITH A RELATIVELY DRY ATMOSPHERE WILL
SUPPRESS CONVECTION. THE CENTER OF SURFACE HIGH PRESSURE WILL
LINGER IN THE WESTERN ATLANTIC...YET CONTINUE TO CONTROL OUR
WEATHER. STILL EXPECT ABOVE NORMAL TEMPERATURES WITH AFTERNOON
HIGHS IN THE MID 80S TO LOWER 90S AND LOWS IN THE LOWER TO MIDDLE
60S.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
GFS/ECMWF INDICATE UPPER RIDGE NEAR THE SOUTHEAST COAST TO MOVE
EAST...WHILE UPPER ENERGY OVER FLORIDA SLOWLY SHIFTS
NORTH...JOINED BY OTHER IMPULSES SHIFTING EAST FROM THE EASTERN
PACIFIC...TO PROVIDE SOME TROUGHINESS AND POSSIBLY A CLOSED LOW
OVER THE DEEP SOUTH...MAINLY TO OUR WEST FOR THE END OF THE WEEK.
THIS ALONG WITH MOISTURE RETURN WILL BRING A CHANCE FOR
SHOWERS/THUNDERSTORMS MAINLY TO OUR WEST. ACCEPTED GUIDANCE
CONSENSUS OF SLIGHT CHANCE POPS FRI/SAT.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD...WITH SOME EARLY
MORNING MVFR POSSIBLE IN FOG/STRATUS. WEAK HIGH PRESSURE OVER THE
REGION WILL REMAIN IN PLACE THROUGH THE PERIOD. MAIN CONCERN
REMAINS POTENTIAL FOR EARLY MORNING FOG AND STRATUS. WITH
DEWPOINT DEPRESSIONS OF SEVERAL DEGREES HAVE DELAYED THE ONSET OF
FOG AND STRATUS AS WELL AS IMPROVED CIGS AND VSBYS FROM PREVIOUS
ISSUANCE. CONTINUE TO EXPECT MVFR FOG AT ALL TAF SITES WITH IFR
POSSIBLE AT AGS. FOG WILL DISSIPATE WITH SUNRISE AND MIXING WITH
ALL TAF SITES RETURNING TO VFR BY 14Z. REMAINDER OF PERIOD WILL BE
VFR WITH WINDS UNDER 7 KNOTS.
EXTENDED AVIATION OUTLOOK MONDAY THROUGH THURSDAY...NO SIGNIFICANT
IMPACTS EXPECTED TUESDAY THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1212 AM EDT MON APR 30 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 352 PM EDT SUN APR 29 2012
A BROAD QUASI ZONAL TO SOUTHWEST FLOW WILL MAINTAIN ITSELF OVER
MOST OF THE NEXT WEEK...WITH SEVERAL FRONTAL WAVES AND THUS
OPPORTUNITIES FOR SHOWERS AND THUNDERSTORMS PRESENTING THEMSELVES
ACROSS CENTRAL INDIANA. THIS SOUTHWEST FLOW WILL ALSO ALLOW
TEMPERATURES TO BE SEASONABLY WARM FOR MUCH OF THE NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
ISSUED AT 1030 PM EDT SUN APR 29 2012
HAD TO LOWER TEMPERATURES A FEW DEGREES AT MANY LOCALES BASED ON
OBSERVATIONS AND THE WARM FRONT STILL JUST SOUTHWEST OF THE
INDIANAPOLIS COUNTY WARNING AREA. THE FRONT IS STILL EXPECTED TO
LIFT NORTHEAST ACROSS NORTHEAST PARTS OF THE FORECAST AREA BY 12Z
MONDAY. MEANWHILE...A FEW SHOWERS WERE DEVELOPING ACROSS
ILLINOIS AND MAY GRAZE OUR NORTHWEST OVERNIGHT IN ADDITION TO STORMS
ACROSS MISSOURI. THUNDERSTORMS ARE ALSO POSSIBLE WITH MOST UNSTABLE
CAPES TO AROUND 300 J/KG ACROSS OUR NORTHEAST AND 900 OVERNIGHT.
STILL...LIKELY LOOKS GOOD NORTHWEST LESSENING TO SLIGHT CHANCE
SOUTHEAST.
PREVIOUS DISCUSSION FOLLOWS...
FOCI FOR TONIGHT ARE POPS AND THUNDER CHANCES. MODELS ARE IN
GENERAL AGREEMENT ON LARGE SCALE FEATURES...BUT LEANED TOWARD NAM
AS OTHER MODELS APPEAR TO BE TOO WET BASED ON CURRENT TRENDS.
WARM FRONT SHOULD GRADUALLY PUSH NORTHWARD TONIGHT...AS A WEAK
SURFACE LOW MOVES OUT OF THE CENTRAL PLAINS. MOST GUIDANCE
APPEARED A BIT TOO AGGRESSIVE ON PRECIP WHEN MUCH OF THE
CONVECTION TO OUR WEST HAS STRUGGLED TO MAKE IT EASTWARD TODAY.
RAPID REFRESH AND RUC DEPICT BEST CHANCES OF PRECIP TONIGHT ACROSS
OUR NORTHWEST...AND CONSENSUS APPROACH TEMPERED SLIGHTLY DEPICTS
THIS WELL. INSTABILITY IS THERE BUT MINIMAL...AND BASED ON SREF
THUNDER PROBS HAVE GONE WITH ISOLATED THUNDER MENTION RATHER THAN
STRAIGHT THUNDERSTORM FORECAST. DID GO WITH CHANCE THUNDER IN THE
NORTHWEST LATE WHERE PROBABILTIES ARE A BIT HIGHER.
CONSENSUS APPROACH ON TEMPS AGREES WELL WITH UPSTREAM MINS FROM
LAST NIGHT...AND WILL STICK CLOSE TO THIS.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
ISSUED AT 352 PM EDT SUN APR 29 2012
FOCUS REMAINS PRECIP CHANCES THROUGHOUT...WITH BOUNDARY REMAINING
IN THE AREA IN ONE FORM OR ANOTHER AND ONE OR MORE VERY SUBTLE
WAVES PERHAPS AIDING SHOWER AND THUNDERSTORM DEVELOPMENT. POPS
APPEARED A BIT HIGH IN PLACES...BUT NOT BY MUCH...GIVEN THE LACK
OF SIGNIFICANT UPPER LEVEL SUPPORT THROUGH THE FIRST PART OF THE
WEEK. HOWEVER...EXPECT THAT MESOSCALE INFLUENCES WILL HELP MAKE UP
FOR THIS. LEANED HEAVILY ON SREF THUNDER PROBS AND BOUNDARY
POSITION FOR DELINEATING BETWEEN WHERE TO FORECAST STRAIGHT
THUNDERSTORMS AND WHERE TO GO MORE SHOWERS WITH ISOLATED THUNDER
MENTION.
SLIGHT RISK FOR TOMORROW AND SEE TEXT FOR TUESDAY APPEAR
REASONABLE BASED ON MODEL CAPE/SHEAR PROFILES. IN SOMEWHAT TYPICAL
FASHION...AFTERNOON AND EARLY EVENING WOULD BE PREFERRED TIMES FOR
SEVERE BOTH DAYS.
ON TEMPS...GENERALLY A CONSENSUS APPROACH LOOKED OK...EXCEPT IT
APPEARED TO BE A FEW DEGREES COOL IN MOST PERIODS BASED ON LOW
LEVEL THICKNESSES. MINOR TWEAKS UPWARD WERE REQUIRED.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
ISSUED AT 230 PM EDT SUN APR 29 2012
ECMWF AND GFS HINT AT A LINGERING FRONTAL BOUNDARY AND NUMEROUS
WEAK SHORT WAVES PUSHING THROUGH THE OHIO VALLEY THROUGH THE FIRST
PART OF THE WEEKEND. CONFIDENCE IN THESE FEATURES IS
LOW...ALTHOUGH GIVEN THE PATTERN...LOW CHANCE POPS WILL BE NEEDED
THROUGH MUCH OF THE WORK WEEK. ALL BLEND HANDLES THIS RATHER WELL.
BY NEXT SUNDAY...THE ECMWF IS SIGNALING A CHANGE AS HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES...PUSH THE FRONTAL BOUNDARY SOUTH.
FOR NOW THIS WILL BE THE MAIN PERIOD WHERE WE WILL BE ABLE TO
REMOVE THE POPS.
THE SOUTHERLY FLOW EXPECTED THROUGH THE PERIOD ALONG WITH SHOULD
PROVIDE ABOVE NORMAL TEMPERATURES THROUGH MUCH OF THE WEEK.
&&
.AVIATION /DISCUSSION FOR THE 300600Z TAFS/...
ISSUED AT 1211 AM EDT MON APR 30 2012
UPPER WAVE CURRENTLY PUSHING ACROSS MISSOURI EXPECTED TO MOVE INTO
THE WESTERN ZONES TOWARDS 301000Z OR SO BASED ON SHORT TERM MODEL
DATA AND EXTRAPOLATION. QUITE A BIT OF CONVECTION HAS DEVELOPED WITH
THIS FEATURE OVER THE PAST FEW HOURS. ORIENTATION OF LOW LEVEL JET
TONIGHT SUGGESTS THE BEST LIFT WILL BE OVER THE NORTHWEST...SO THINK
THE HIGHEST THREAT OF CONVECTION WILL BE IN THE KLAF AREA ROUGHLY
301000Z-301400Z AS THE UPPER WAVE MOVES THROUGH. LOWER THREAT OF
CONVECTION EXPECTED AT THE OTHER TAF SITES OVERNIGHT INTO THE MID TO
LATE MORNING HOURS ON MONDAY GIVEN THE COMBINATION OF SOME LIFT
ASSOCIATED WITH THE UPPER WAVE AND APPROACHING WARM FRONT. APPEARS
FRONT AND WAVE WILL BE NORTHEAST OF THE TAF SITES BY THE LATE
MORNING HOURS...SO CONVECTIVE THREAT MAY DIMINISH BY THAT TIME.
CONVECTIVE CLOUD BASES 040-050.
OUTSIDE OF ANY CONVECTION...UNRESTRICTED VISIBILITY/SURFACE WINDS
UNDER 15 KTS EXPECTED THROUGH 301800Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...NIELD/KOCH
SHORT TERM...NIELD
LONG TERM....PUMA
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1153 PM CDT SUN APR 29 2012
...UPDATED FOR 06Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
FORECAST CONCERNS CENTER AROUND CHANCE FOR LINGERING PRECIPITATION
TONIGHT. LARGE AREA OF PRECIP CONTINUES TO PUSH NORTH THROUGH THE
CWA...AND LINES UP WELL WITH ISENTROPIC LIFT AREA ON THE RUC 290K
SURFACE. HAVE TRENDED POPS TO CORRELATE WITH THIS AREA OF LIFT
TRANSLATING NORTH TO NORTHEASTWARD WITH TIME OVER THE NEXT 3 TO 6
HOURS. DEEPER SATURATION ENDS BY MID EVENING...WITH SOME DRIER AIR
MOVING IN ALOFT...WITH LOWEST LAYERS REMAINING SATURATED. SOME WEAK
ISENTROPIC LIFT STILL AROUND IN AREAS WITH THE MORE SHALLOW
SATURATION...THEREFORE HAVE ALSO MENTIONED SOME PATCHY DRIZZLE FOR
THE EVENING HOURS. ANY ELEVATED INSTABILITY CONFINED TO THE SOUTHERN
PORTION OF THE CWA...BUT HAS NOT MATERIALIZED MUCH EVEN THIS
AFTERNOON...SO ONLY HAVE SOME ISOLATED THUNDER MENTION ACROSS FAR
SOUTH FOR THIS EVENING. WITH THE SHALLOW LOW LEVEL
SATURATION...EXPECT STRATUS TO CONTINUE THROUGH THE NIGHT. WITH
WINDS EXPECTED TO BECOME LIGHT AND VARIABLE AS WEAK HIGH PRESSURE
BUILDS INTO THE STATE...SHALLOW MOISTURE AND RESIDUAL SURFACE
MOISTURE FROM THE RAINFALL COULD ALSO HAVE AREAS OF FOG POSSIBLY
DENSE FORM ACROSS THE CWA BY LATE EVENING INTO THE OVERNIGHT HOURS.
FOR NOW JUST MENTIONED THE FOG IN THE GRIDS...BUT WILL HAVE TO
MONITOR ITS DEVELOPMENT TO DETERMINE IF IT WILL BECOME DENSE.
OVERALL EXPECT PRECIP TO CLEAR FASTER THAN IN PREVIOUS
FORECASTS...SO HAVE ENDED ANY PRECIPITATION BY LATE EVENING AND HAVE
GONE DRY IN THE LATE NIGHT HOURS.
.LONG TERM /MONDAY THROUGH SUNDAY/...
WITH SYSTEM MOVING A BIT FASTER...MON SHOULD BE A DRY DAY AND LIKELY
THE ONLY FULLY DRY PERIOD OF THE FORECAST. BROAD SOUTHWEST FLOW
WILL PERSIST OVER THE CENTRAL U.S. FOR THE NEXT WEEK WITH A SERIES
OF UPPER LEVEL SYSTEM S LIFTING NEWD OUT OF THE SOUTHWEST U.S.
TIMING WILL BE TRICKY...BUT IT DOES APPEAR THERE WILL BE SOME RAIN
DURING EACH OF THE 12 HOUR PERIODS OF THE FORECAST...THOUGH NOT ALL
OF IT. THERE WILL BE INTERMITTENT CHANCES FOR SEVERE WEATHER WITH
THE BEST CHANCES LOOKING LIKE TUE NIGHT AND FRIDAY NIGHT RIGHT NOW.
SOME CAPPING IS BEGINNING TO TAKE PLACE WHICH WILL CUT DOWN THE
SEVERE POTENTIAL SOME. ALL IN ALL IT DOES LOOK LIKE A DECENT AMOUNT
OF RAIN DURING THE NEXT WEEK. NOT SURE THE HEAVIEST WILL BE IN THE
DRIEST AREAS HOWEVER. THE THE DRY NWRN ZONES WILL GET ABOVE NORMAL
RAINFALL THIS WEEK. TEMPS WILL WARM ABOVE NORMAL ON MONDAY AND
REMAIN THAT WAY THROUGH THE WEEK.
&&
.AVIATION...30/06Z
LOW LEVEL EASTERLY WINDS AND MOISTURE WILL CONTINUE TO PRODUCE
WIDESPREAD IFR CEILINGS AND VISIBILITIES OVERNIGHT AT ALL TAFS
SITES. THE POOR CONDITIONS WILL IMPROVE ON MONDAY AS WINDS BECOME
SOUTHERLY AND INCREASE DURING THE DAY. THIS WILL ALLOW THE LOW LEVEL
INVERSION THAT HAS BEEN IN PLACE TO GRADUALLY MIX OUT WITH FOG AND
STRATUS DISSIPATING DURING THE MORNING. WIDESPREAD VFR CONDITIONS
ARE THEN EXPECTED BY MONDAY AFTERNOON AT ALL TAF SITES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MJB
LONG TERM...MS APR 12
AVIATION...KS/COGIL
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
139 AM EDT MON APR 30 2012
.SYNOPSIS...
ISSUED AT 305 PM EDT SUN APR 29 2012
HIGH PRESSURE WILL MOVE EAST AND A WARM FRONT WILL PUSH NORTH
TOWARDS SOUTHERN LOWER MICHIGAN TONIGHT. SOME SHOWERS AND
THUNDERSTORMS WILL BE ARRIVING AFTER MIDNIGHT TONIGHT THEN SPREAD
NORTH ON MONDAY. WARMER TEMPERATURES ALONG WITH SCATTERED SHOWERS
AND THUNDERSTORMS CAN BE EXPECTED FROM TUESDAY THROUGH THURSDAY.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 305 PM EDT SUN APR 29 2012
AREA OF ISENTROPIC ASCENT NORTH OF SFC WARM FRONT IS GENERATING
RAIN ACROSS ILLINOIS THIS AFTERNOON. THIS WILL CONTINUE NORTHEAST
AND EDGE INTO FAR SOUTHWEST LOWER MICHIGAN THIS EVENING. LEADING EDGE
WILL HAVE TO OVERCOME DRY AIR INITIALLY BUT 12Z MODEL RH PROFILES
AND HRRR RUC INDICATE THE DRY AIR WILL BE OVERCOME AS LOW LEVEL
FLOW GOES SOUTHEAST WITH THE SFC RIDGE MOVING EASTWARD.
WILL BRING CHANCE POPS IN THIS EVENING AND THEN EXPAND NORTHWARD
AFTER MIDNIGHT. WILL HAVE THUNDERSTORMS ACROSS THE SOUTHERN
FORECAST AREA AS POTENTIAL FOR ELEVATED CONVECTION EXISTS WITH
TOTAL TOTALS IN THE UPPER 40S. MAIN SLUG OF QPF MOVES EAST DURING
THE DAY ALONG WITH DEEP MOISTURE...WHICH MEANS LIKELY POPS IN THE
MORNING FOLLOWED BY CHANCE POPS IN THE AFTERNOON.
MAX TEMPS WILL BE TRICKY ON MONDAY AS MODEL RH PROFILES SUGGEST
LOWER CLOUDS WILL STICK AROUND ALL DAY...AND UPSTREAM OBS IN THE
CLOUDS NORTH OF THE WARM FRONT THIS AFTERNOON ARE CURRENTLY STUCK
IN THE 40S. WENT A BIT BELOW GUIDANCE FOR MONDAY MAXES.
MONDAY NIGHT WILL SEE LOW CLOUDS DECREASE AS WEAK SFC RIDGING
BUILDS IN. WILL GO WITH A DRY FORECAST AS DEEP MOISTURE HAS
DEPARTED BY EVENING. GUIDANCE TEMPS HAVE TRENDED DOWNWARD AND SO
TWEAKED MINS LOWER.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 305 PM EDT SUN APR 29 2012
THE MAIN LONG TERM FCST CHALLENGE CONTINUES TO INVOLVE DETERMINING
PROBABILITIES FOR RAIN AND CONVECTION THROUGH MOST OF THE LONG RANGE
FCST PERIOD.
A WEAK HIGH PRESSURE RIDGE WILL PRODUCE DRY WX THROUGH AT LEAST
MIDDAY TUESDAY. WE WILL MAINTAIN MENTION OF A CHC OF SHOWERS/STORMS
OVER OUR SOUTHERN FCST AREA TUESDAY AFTERNOON AS THE WARM FRONT
LIFTS NORTH. IT WILL BE MILDER TUESDAY WITH MAX TEMPS REACHING THE
LOW TO MID 70S. SHOWERS AND A FEW TSTORMS ARE ANTICIPATED TUESDAY
NIGHT AS THE WARM FRONT CONTINUES TO LIFT NORTHWARD.
THE MODERATING TREND WILL CONTINUE WEDNESDAY WITH OUR FCST AREA
SOLIDLY IN THE WARM SECTOR WITH MAX TEMPS REACHING THE UPPER 70S TO
LOWER 80S. WE WILL MAINTAIN CHC POPS FOR SHOWERS/TSTORMS WEDNESDAY
AS MODERATE INSTABILITY DEVELOPS IN THE WARM SECTOR. HOWEVER I AM
NOT CONVINCED THAT THERE WILL BE A GOOD TRIGGERING MECHANISM/FOCUS
FOR CONVECTIVE INITIATION TO OCCUR. MOST OF THE DAY WILL LIKELY BE
DRY. 12Z GFS GUIDANCE SUGGESTS THE BETTER CONVECTIVE POTENTIAL
WEDNESDAY AFTERNOON WILL BE MUCH FURTHER NORTH NEAR THE WARM FRONT
AND ALSO WELL TO OUR NW IN CLOSER PROXIMITY TO THE SFC LOW OVER THE
UPPER MIDWEST.
THE WEDNESDAY NIGHT TIME FRAME REMAINS FAVORED FOR CONVECTIVE
DEVELOPMENT DUE LARGELY TO FORCING FROM A 35 TO 45 KT LLJ. 1000-850
MB MOISTURE TRANSPORT ALSO LOOKS FAVORABLE BY WEDNESDAY EVENING.
SHOWERS AND TSTORMS WILL LIKELY LINGER/REDEVELOP ON THURSDAY WITH
SHOWERS LINGERING FRIDAY BEFORE A COOLER AND DRIER AIRMASS ADVECTS
FOR THE WEEKEND WITH TEMPS RETURNING TO NEAR NORMAL BY THEN.
CANNOT RULE OUT A FEW STRONG TO SEVERE STORMS LATE WEDNESDAY THROUGH
THURSDAY AS INSTABILITY INCREASES ALONG WITH BRIEFLY STRONGER
FORCING FROM THE LLJ. HOWEVER WE CONCUR WITH THE PREVIOUS SHIFT THAT
THE OVERALL SEVERE WX THREAT MIDWEEK LOOKS FAIRLY LOW DUE TO SEVERAL
LIMITING FACTORS INCLUDING WEAK DEEP LAYER SHEAR STAYING GENERALLY
UNDER 30 KTS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 139 AM EDT MON APR 30 2012
SHOWER ARE CURRENTLY MOVING THROUGH THE REGION. SHOULD SEE A
DECREASE IN COVERAGE FROM 06-10Z BEFORE MORE SHRA MOVE INTO THE
AREA FROM ILLINOIS. NEPH ANALYSIS INDICATED MVFR/IFR/LIFR
CONDITONS HAVE BEEN SLOW TO MOVE NEWED FROM IOWA/ILLINOIS. STILL
THINK THAT WILL HAPPEN BUT MORE TOWARD MID MORNING. MOST AREAS
SHOULD SEE CIGS FALL TO 700-1K FT BY LATE MORNING.
&&
.MARINE...
ISSUED AT 305 PM EDT SUN APR 29 2012
WINDS AND WAVES SHOULD REMAIN BELOW SMALL CRAFT CRITERIA THROUGH
TUESDAY. THUNDERSTORMS ARE POSSIBLE SOUTH OF MUSKEGON ON MONDAY.
&&
.HYDROLOGY...
ISSUED AT 305 PM EDT SUN APR 29 2012
HEAVY RAIN IS POSSIBLE WEDNESDAY AND THURSDAY WHICH COULD LEAD TO
RISES ON THE RIVERS BY THE END OF THE WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS...OSTUNO
SHORT TERM...OSTUNO
LONG TERM...LAURENS
AVIATION...93
HYDROLOGY...OSTUNO
MARINE...OSTUNO
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
346 AM CDT MON APR 30 2012
.DISCUSSION...
IT APPEARS TO BE SHAPING UP TO BE A BUSY WEEK WEATHERWISE... WITH
CHANCES FOR PCPN SOMEWHERE OVER THE CWFA NEARLY EVERY DAY... AND
THE POTENTIAL FOR SEVERE WEATHER LATE TUESDAY AFTERNOON INTO
TUESDAY NIGHT. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR
ANALYSES SHOW THE PESKY UPPER LOW WHICH WAS OVER THE PLAINS THE
PAST SEVERAL DAYS HAS FINALLY LIFTED NORTHEAST INTO CENTRAL
CANADA. UPPER PV ANALYSIS SHOWS A FILAMENT EXTENDING SOUTH FROM
THIS INTO CENTRAL MINNESOTA AT THE CURRENT TIME... HELPING TO KEEP
A FEW SHRA GOING OVER THE NORTH CENTRAL PORTION OF THE STATE. A
SECOND PV FEATURE IS APPARENT NEAR THE SOUTHEAST MINNESOTA/WEST
CENTRAL WISCONSIN BORDER. THIS COMPACT ANOMALY IS ALSO LIFTING
NORTHEAST... HELPING TO TAKE ITS ASSOCIATED AREA OF SHRA ALONG
WITH IT. THE NEXT UPPER LEVEL FEATURE OF CONSEQUENCE IS A SHORTWAVE
APPARENT OFF THE PACIFIC NORTHWEST COAST. THIS SYSTEM WILL WORK
ACROSS THE NORTHWEST CONUS AND NORTHERN ROCKIES OVER THE NEXT
24-36 HOURS... THEN PUSH INTO THE NORTHERN PLAINS TUESDAY
AFTERNOON AND EVENING... HELPING TO SET THE STAGE FOR
THUNDERSTORMS AND POSSIBLE SEVERE WEATHER OVER OUR AREA LATE
TUESDAY AFTERNOON AND TUESDAY NIGHT. THE UPPER RIDGE CURRENTLY IN
PLACE OVER THE SOUTHEAST CONUS LOOKS TO STUBBORNLY REMAIN IN PLACE
THROUGH THE WEEK... WHICH WILL HELP TO MAINTAIN SOUTHWEST UPPER
FLOW OVER THE NORTH CENTRAL US. THIS MEANS THE SYSTEM MOVING INTO
THE AREA TUESDAY NIGHT WILL HAVE A TOUGH TIME DISPLACING THE
BAROCLINIC ZONE SOUTHEAST OF OUR AREA... LEAVING AN UNSETTLED
SECOND HALF OF THE WEEK AS MOISTURE AND INSTABILITY LOITER NEARBY
AND A FEW ADDITIONAL SHORTWAVES RIPPLE NORTHEAST FROM THE CENTRAL
ROCKIES AND THROUGH THE NORTHERN PLAINS. THE MODELS ARE ACTUALLY
IN QUITE GOOD AGREEMENT ON THE OVERALL LARGE SCALE PATTERN THROUGH
THE WEEK. HOWEVER... THERE IS A FAIR DEGREE OF SPREAD IN THEIR
TIMING OF INDIVIDUAL SHORTWAVE FEATURES... THE EXACT POSITION OF
THE MAIN BAROCLINIC ZONE THROUGH THE WEEK... AND THE INTERPLAY OF
THESE FEATURES WITH CONVECTIVE DEVELOPMENT. STUCK CLOSE TO A BLEND
OF THE NAM AND GFS THROUGH TUESDAY... THEN HAD A TOUGH TIME
PUTTING MUCH FAITH IN THE SPECIFIC DETAILS OF ANY PARTICULAR
SOLUTION OR COMBINATION OF SOLUTIONS AFTER THAT POINT. THE MAIN
IDEA IS THAT AFTER TUESDAY WE WILL HAVE THE BAROCLINIC ZONE HANG
UP EITHER OVER THE SOUTHERN PORTION OF OUR AREA OR JUST TO THE
SOUTH... WHICH WILL BE CLOSE ENOUGH FOR PERIODIC PCPN CHANCES
THROUGH THE BALANCE OF THE WEEK AS SHORTWAVES OCCASIONALLY MIGRATE
THROUGH THE REGION WITH BOUNDARY LAYER BASED AND/OR ELEVATED
INSTABILITY REMAINING IN PLACE.
FOR TODAY... ABUNDANT LOW CLOUDS AND SOME PATCHY FOG WILL BE IN
PLACE TO START THE DAY... BUT WITH MID-HIGH CLOUDS PRIMARILY SOUTH
OF THE AREA INSOLATION SHOULD WORK TO ERODE THINGS THROUGH THE
MORNING HOURS. BY AFTERNOON WE SHOULD START TO SEE SOME BETTER
RETURN FLOW SETUP... WHICH SHOULD FURTHER ASSIST IN INCREASING
SUNSHINE ACROSS THE AREA. A SECONDARY PV ANOMALY ROTATING AROUND
THE UPPER LOW TO OUR NORTH... CURRENTLY SEEN OVER SOUTHERN
SASKATCHEWAN... WILL SLIDE BY TO OUR NORTH THIS AFTERNOON...
POSSIBLY BRINGING A FEW SHRA TO THE NORTH CENTRAL AND NORTHEAST
PORTION OF THE AREA. WOULDN/T BE SHOCKED IF A SHRA MADE IT AS FAR
SOUTH AS THE TWIN CITIES METRO LATER THIS AFTERNOON AS THIS
FEATURE MOVES BY TO OUR NORTH... BUT FOR NOW STUCK CLOSER TO THE
MODEL CONSENSUS OF KEEPING PCPN NORTH OF THAT AREA. RETURN FLOW
WILL INCREASE MARKEDLY OVER THE WESTERN HALF OF THE AREA
TONIGHT... WITH SUFFICIENT MOISTURE ADVECTION FOR PERHAPS SOME
SHRA/TSRA TO GET GOING OVERNIGHT ACROSS WEST CENTRAL MINNESOTA.
THE BEST FOCUS OF MOISTURE AND FORCING ALONG THE ELEVATED WARM
FRONTAL BOUNDARY LOOKS TO BE NORTH OF OUR AREA LATE TONIGHT INTO
TUESDAY MORNING... BUT SOME ACTIVITY COULD CERTAINLY EXTEND BACK
INTO WEST CENTRAL AND CENTRAL MINNESOTA.
TUESDAY WILL BRING EVEN WARMER TEMPERATURES INTO THE AREA AS WE
FIND OURSELVES IN THE WARM SECTOR AHEAD OF A FRONTAL BOUNDARY
EXTENDING FROM LOW PRESSURE IN SOUTHWEST MANITOBA BACK INTO
CENTRAL NEBRASKA. EXPECT TO SEE SHRA/TSRA DEVELOP JUST WEST OF OUR
AREA TUESDAY AFTERNOON... WITH PERHAPS SOME ADDITIONAL STORMS
DEVELOPING OVER OUR AREA OUT AHEAD OF WHAT SHOULD EVENTUALLY
EVOLVE INTO A BROKEN LINE OF STORMS MOVING FROM THE EASTERN
DAKOTAS INTO WESTERN MINNESOTA DURING THE LATE AFTERNOON AND EARLY
EVENING. THE BEST UPPER FORCING ASSOCIATED WITH THE SHORTWAVE
CURRENTLY OFF THE PACIFIC NORTHWEST COAST WON/T WORK INTO THE AREA
UNTIL LATER TUESDAY EVENING AND INTO THE OVERNIGHT HOURS.
HOWEVER... THERE APPEARS TO BE MORE THAN SUFFICIENT LOW LEVEL
CONVERGENCE AND FRONTOGENETICAL FORCING TO GET STORMS GOING IN AN
ENVIRONMENT WHICH SHOULD SEE MLCAPE VALUES AOA 1500 J/KG AND 0-6KM
BULK SHEAR AOA 40KT. WHEN THE BETTER LARGE SCALE FORCING WORKS
INTO THE REGION LATER IN THE EVENING AND DURING THE OVERNIGHT...
IT WILL LIKELY SERVE TO KEEP THE ACTIVITY GOING AS IT MOVES ACROSS
THE REMAINDER OF MINNESOTA AND INTO WESTERN WISCONSIN. AS THINGS
MIGRATE EAST DURING THE EVENING WOULD EXPECT TO SEE ACTIVITY
EVOLVE INTO A LINEAR SYSTEM... WITH PERHAPS SOME EMBEDDED BOWS
GIVEN 0-2KM BULK SHEAR AOA 25KT ORIENTED PERPENDICULAR TO AN
ANTICIPATED NORTH-SOUTH LINEAR SYSTEM. PRIMARY SEVERE THREATS
SHOULD BE DAMAGING WINDS AND LARGE HAIL FROM LATE TUESDAY
AFTERNOON THROUGH AT LEAST 06Z THAT NIGHT... ALTHOUGH A FEW
TORNADOES CANNOT BE RULED OUT WITH DISCRETE SUPERCELLS WHICH MAY
OCCUR EARLY-ON AS WELL AS EMBEDDED SUPERCELL
STRUCTURES/MESOVORTICES WITH A POTENTIAL LINEAR SYSTEM LATER IN
THE EVENING. THERE REMAINS A FAIR DEGREE OF SPREAD IN THE MODEL
DETAILS WITH RESPECT TO SHEAR PROFILES... PARTICULARLY SUB-2KM
SHEAR BOTH IN TERMS OF SPEED AND DIRECTIONAL COMPONENTS. NEEDLESS
TO SAY... THINGS WILL NEED TO BE MONITORED OVER THE NEXT 24 HOURS
AS THINGS COME INTO BETTER FOCUS AND ADDITIONAL INFORMATION
BECOMES AVAILABLE FROM CONVECTION ALLOWING MODELS. AT THIS
POINT... THE INITIAL CONVECTIVE DEVELOPMENT NEAR THE
DAKOTAS/MINNESOTA BORDER IS OCCURRING RIGHT AT THE END OF THE HIGH
RESOLUTION WINDOW RUNS... ALTHOUGH IT SHOULD BE NOTED THAT BOTH
THE NMM AND ARW SHOW A FEW INDIVIDUAL STORMS QUICKLY ACQUIRING
UPDRAFT HELICITY VALUES AOA 40 M2/S2 BETWEEN 22Z AND 00Z. IN
ADDITION... THE 03Z SREF TORNADO INGREDIENT PROBABILITIES HIGHLIGHT
AN AREA NEAR AND WEST OF THE I-35 CORRIDOR AROUND 00-03Z... SUGGESTING
THERE MAY BE A WINDOW OF TIME WHEN CONDITIONS WILL BE FAVORABLE
FOR TORNADIC STORMS.
THE REMAINDER OF THE FORECAST IS QUITE MUDDY... FIGURATIVELY AND
PERHAPS LITERALLY... AFTER TUESDAY NIGHT/S SYSTEM MOVES THROUGH
THE AREA. WITH THE UPPER RIDGE REMAINING IN PLACE IN THE SOUTHEAST
CONUS... HEIGHTS FALL LITTLE ACROSS THE NORTH CENTRAL PART OF THE
COUNTRY... AND THEREFORE THE FRONTAL BOUNDARY WHICH PUSHES INTO
THE AREA TUESDAY NIGHT WILL LINGER NEARBY FOR SEVERAL DAYS.
SHOWERS AND THUNDERSTORM CHANCES LOOK GOOD FROM WEDNESDAY INTO THE
WEEKEND. THE SOUTHERN PORTION OF THE AREA... CLOSER TO THE OLD
FRONTAL BOUNDARY... COULD SEE A SIGNIFICANT AMOUNT OF PCPN OVER
THAT PERIOD OF TIME DEPENDING UPON HOW INDIVIDUAL SHORTWAVES MOVE
THROUGH THE REGION AND WHERE CONVECTION SETS UP AND TRACKS. IT
WILL DEFINITELY NOT BE RAINING THE ENTIRE TIME PERIOD... BUT EACH
DAY LOOKS TO HAVE SOME CHANCE FOR SHRA/TSRA. HOPEFULLY THE
FORECAST CAN BE REFINED TO BETTER IDENTIFY DRY/WET PERIODS AS THE
WEEK PROGRESSES.
&&
.AVIATION.../06Z TAF ISSUANCE/
AREA OF SHOWERS CURRENTLY HEADING INTO WESTERN WISCONSIN WILL
CONTINUE TO DO SO OVER THE NEXT FEW HOURS...WITH A FEW TRAILING
SPRINKLES IN ITS WAKE. LOW STRATUS SHOULD FALL TO MVFR LEVELS
OVERNIGHT...WITH A FEW HOURS OF IFR AT KMSP...KEAU...AND KRNH.
WEAK WINDS AND LOW LEVEL MOISTURE WILL PROMOTE SOME FOG
DEVELOPMENT...BEFORE THE WESTERLY WINDS PICK UP EARLY MONDAY
MORNING. FORECAST SOUNDINGS SHOW THE POTENTIAL FOR SOME GUSTS NEAR
25 KTS TOMORROW AFTERNOON...BUT CONFIDENCE WAS TOO LOW TO INCLUDE
IN THE TAFS...SO HAVE MID TO UPPER TEENS AS OF NOW.
KMSP...MODEL GUIDANCE RATHER PESSIMISTIC FOR CEILINGS
OVERNIGHT...WITH A COUPLE SOLUTIONS WANTING TO GO LIFR. TRIED TO
TIME THE LOWEST CEILINGS WITH THE TEMPO GROUP...AND COULD SEE SOME
LOWERED VISBYS DURING THIS TIME AS WELL.
/OUTLOOK/
TUESDAY...VFR/MVFR WITH TSRA POSSIBLE...ESPECIALLY
EVENING/OVERNIGHT WINDS S AT 20KTS.
WEDNESDAY...VFR/MVFR WITH -TSRA POSSIBLE. WINDS SE AT 5KT.
THURSDAY...VFR/MVFR WITH -TSRA POSSIBLE. WINDS SW AT 5KT.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
1236 AM CDT MON APR 30 2012
...UPDATE TO AVIATION...
.UPDATE...
/ISSUED 1051 PM CDT SUN APR 29 2012/
POTENTIALLY DANGEROUS HEAVY RAINFALL AND FLASH FLOOD SITUATION
UNFOLDING ACROSS PORTIONS OF THE OUTLOOK AREA.
WAVY...STATIONARY SURFACE BOUNDARY EXTENDS FROM NEAR ROLLA TO JUST
NORTH OF NEVADA AND FORT SCOTT. OVER THE PAST FEW HOURS...LARGE
SCALE LIFT HAS INCREASE AND CONVECTION ALONG AND SOUTH OF THIS
BOUNDARY HAS BLOSSOMED. COMBINATION OF MULTICELL CLUSTERS AND A
FEW EMBEDDED SUPERCELLS HAVE BEEN OBSERVED TO THIS POINT.
SUPERCELL STRUCTURES AND ANY BOWING SEGMENTS THAT CAN DEVELOP WILL
POSE OUR MAIN SEVERE WEATHER THREAT...WITH MARGINALLY SEVERE HAIL
AND LOCALIZED DAMAGING WIND GUSTS THE PRIMARY CONCERN. THE LOW
LEVEL JET HAS RAMPED UP...RESULTING IN A LIMITED TORNADO RISK...
MAINLY ACROSS EXTREME SOUTHEAST KANSAS AND ADJACENT COUNTIES IN
MISSOURI FOR THE NEXT COUPLE OF HOURS. REALLY CANNOT RULE OUT A
FEW SEVERE CELLS FROM TIME TO TIME AT ANY POINT FOR THE REST OF
TONIGHT. AS THE LOW LEVEL JET VEERS THE CURRENT AXIS OF CONVECTION
WILL TEND TO SHIFT TO THE SOUTH WITH NEW CELL DEVELOPMENT POSSIBLE
ON THE SOUTHEASTERN FLANK CLOSER TO THE I-44 CORRIDOR. MARGINALLY
SEVERE HAIL/LOCALIZED DAMAGING WIND WILL REMAIN THE PRIMARY RISKS.
OF LARGER CONCERN WILL BE HEAVY RAINFALL PRODUCTION OVERNIGHT.
AT THE SURFACE...DEWPOINT POOLING IS BEING OBSERVED. MEANWHILE A 30
TO 40 KT LOW LEVEL JET IS PROVIDING A STRONG INFLUX OF LOW LEVEL
MOISTURE. PRECIPITABLE WATER VALUES AROUND 1.8 INCHES HAVE BEEN
IDENTIFIED BY RUC INITIALIZATIONS ALONG AND SOUTH OF THE SURFACE
BOUNDARY...WHICH IS IN THE 99TH PERCENTILE FOR THIS TIME OF YEAR.
IN ADDITION...TRADITIONAL STORM MOTION VECTORS ARE RATHER LIGHT
NEAR THE BOUNDARY AND RECENT RUC PROGS DO NOT CHANGE THIS FOR THE
NEXT 3 TO 6 HOURS. AS A RESULT...THE CURRENT ORIENTATION OF
CONVECTION IS NOT EXPECTED TO CHANGE VERY MUCH OVER THE NEXT 3 TO
6 HOURS.
THUNDERSTORM TRAINING AND EFFICIENT HEAVY RAINFALL PRODUCTION WILL
RESULT IN A SIGNIFICANT RISK OF FLASH FLOODING ACROSS PORTIONS OF
CRAWFORD AND BOURBON COUNTIES IN KANSAS AS WELL AS BARTON...
VERNON...CEDAR AND ST. CLAIR COUNTIES IN MISSOURI OVER THE NEXT
2 TO 4 HOURS. WIDESPREAD RAINFALL OF TWO TO FIVE INCHES IS
EXPECTED...WITH LOCALLY HIGHER AMOUNTS UPWARD OF SEVEN INCHES
POSSIBLE. THE RISK FOR HEAVY RAIN AND FLASH FLOODING IN ADJACENT
COUNTIES WILL HAVE TO BE MONITORED VERY CLOSELY. AS MENTIONED
ABOVE...A VEERING LOW LEVEL JET WILL ALLOW THE AXIS OF CONVECTION
TO SHIFT TO THE SOUTH AND SOUTHEAST AFTER (ROUGHLY) 09Z...SO
TRAINING SHOULD LESSEN WITH TIME AND RAINFALL WILL BEGIN TO AFFECT
AREAS THAT HAVE NOT SEEN MUCH IN THE WAY OF RAIN THE PAST FEW DAYS.
GAGAN
&&
.DISCUSSION...
/ISSUED 335 PM CDT SUN APR 29 2012/
THE ACTIVE WEATHER WILL CONTINUE INTO MONDAY AND AT LEAST PART OF
TUESDAY AS THE EXISTING BOUNDARY REMAINS STALLED ACROSS THE AREA
UNDERNEATH A BROAD SOUTHWESTERLY FLOW ALOFT.
PINPOINTING THE HIGHEST CHANCES OF SHOWERS AND THUNDERSTORMS WILL
BE CHALLENGING BUT THE ACTIVITY WILL LIKELY TEND FOCUS ALONG AND
NORTH OF THE BOUNDARY AS IT INTERACTS WITH THE NIGHT TIME LOW
LEVEL JET.
THE RISK OF SEVERE WEATHER APPEARS TO BE LIMITED AT BEST MONDAY
AND TUESDAY AND WILL BE DEPENDENT ON THE EXTENT OF DESTABILIZATION
THAT CAN OCCUR. MULTIPLE ROUNDS OF SHOWERS AND THUNDERSTORMS WILL
LEAD TO AN INCREASING RISK OF FLASH FLOODING ESPECIALLY FROM
SOUTHEAST KANSAS INTO SOUTHWEST AND CENTRAL MISSOURI ALONG AND
NORTH OF THE BOUNDARY WHERE A FLASH FLOOD WATCH HAS BEEN ISSUED.
WARMER TEMPERATURES AND A DRYING TREND IS IN STORE FROM MID TO
LATE WEEK AS UPPER LEVEL RIDGING GRADUALLY DEVELOPS.
FOSTER
&&
.AVIATION...
/ISSUED 1235 AM CDT MON APR 30 2012/
FOR THE 06Z TAFS (JLN/SGF/BBG)...YET ANOTHER IN A STRING OF VERY
COMPLEX FORECASTS FOR AREA AERODROMES. WELL DEVELOPED AREA OF
SHRA/TSRA ALONG A BOUNDARY TO THE NORTHWEST OF JLN/SGF/BBG WILL
SLOWLY SHIFT SOUTHEASTWARD OVER THE NEXT 3 TO 6 HOURS. CIG/VIS
WILL LOWER TO MVFR AND AT TIMES IFR UNDER THE HEAVIER DOWNPOURS.
THIS ACTIVITY WILL EXIT STAGE EAST BY MIDDAY WITH CLEARING/VFR
CONDITIONS EXPECTED INTO MONDAY EVENING. WILL NEED TO WATCH FOR
SHRA/TSRA REDEVELOPMENT MONDAY EVENING.
GAGAN
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR MOZ055>058-
066>070-077>081-088>090-093-094-101-102.
KS...FLASH FLOOD WATCH UNTIL 10 AM CDT THIS MORNING FOR KSZ073-097-
101.
&&
$$
AREA FORECAST DISCUSSION
NWS HASTINGS NE
432 AM CDT MON APR 30 2012
.SHORT TERM...THROUGH 12Z THURSDAY...LATEST SATELLITE IMAGERY THIS
MORNING INDICATING WIDESPREAD STRATUS ACROSS THE LOCAL AREA.
UNDERNEATH THIS STRATUS...WITH LIGHT WINDS AND ELEVATED
DEWPOINTS...SAW SOME VERY DENSE FOG FORM IN SPOTS ACROSS THE
REGION THE PAST FEW HOURS...WITH THE MOST DENSE AREAS AFFECTING
THE TRI CITIES REGION. WHILE VISIBILITIES WILL IMPROVE SOME
THROUGH THE EARLY MORNING HOURS AS WINDS BEGIN TO INCREASE AND THE
BOUNDARY LAYER ELEVATES...COULD NOT IGNORE NUMEROUS OBSERVATIONS
WITH VISIBILITIES OF 1/4 SM OR LESS...AND WENT AHEAD AND ISSUED A
DENSE FOG ADVISORY THROUGH 10 AM CDT FOR PORTIONS OF SOUTH CENTRAL
NEBRASKA. TO THE EXTREME WEST...ACROSS FURNAS AND GOSPER
COUNTIES...HAVE SEEN A FEW LIGHT SHOWERS SPREAD EASTWARD...AND
SUSPECT CONDITIONS ACROSS THIS AREA HAVE IMPROVED SOME...AS SEEN
IN MCK...SO KEPT THIS AREA OUT OF ADVISORY.
EXPECT THE FEW LIGHT SHOWERS ACROSS WESTERN PORTIONS OF THE
FORECAST AREA THIS MORNING TO SLOWLY DISSIPATE AS THEY ATTEMPT TO
TRACK FURTHER EASTWARD...AS VIRTUALLY NO INSTABILITY OR FORCING
IS EVIDENT TO KEEP THEM GOING. EVEN SO...LATEST MODES ARE TRYING
TO FIRE UP QUITE A BIT OF SHOWER ACTIVITY ACROSS THIS AREA THROUGH
THE AFTERNOON HOURS...BUT GIVEN THEIR HANDLING OF CURRENT
SITUATION...HAVE DISCOUNTED MUCH...IF ANY...FURTHER DEVELOPMENT.
DID MAINTAIN SOME SMALL POPS AS WE GO THROUGH THE DAY ANYHOW...BUT
THINK BULK OF SHOWER ACTIVITY WILL BE WELL TO OUR SOUTH ALONG WARM
FRONTAL BOUNDARY.
AS WE HEAD INTO THE EVENING HOURS TONIGHT...PROGRESSIVE UPPER FLOW
PATTERN WILL CONTINUE ACROSS THE REGION...WITH FOCUS OF NEXT SHORT
WAVE AIMED WELL TO THE SOUTH. ONCE AGAIN...HOWEVER...WITH LIGHT
SOUTHEASTERLY WINDS AND GOOD LOW LEVEL MOISTURE...EXPECT AT LEAST
THE POSSIBILITY FOR SOME PATCHY FOG FORMATION...AND WENT AHEAD AND
INSERTED A MENTION INTO FORECAST FOR TUESDAY MORNING.
THEREAFTER...IT APPEARS THE MAIN FOCUS WILL SHIFT TO THE LATE
AFTERNOON THROUGH EVENING HOURS TUESDAY...WHEN A FRONTAL BOUNDARY
IS FORECAST TO SWEEP SOUTHEASTWARD ACROSS THE LOCAL AREA. WITH
VERY MOIST AIR AHEAD OF THIS BOUNDARY AND MU CAPE VALUES OF
2-3KJ...COULD SEE SOME STRONG OR EVEN SEVERE STORMS DEVELOP ACROSS
THE LOCAL AREA...AND WILL HIGHLIGHT THIS IN HWO.
FOR THE REMAINDER OF THE SHORT TERM...EXPECT YET ANOTHER
BOUNDARY...COUPLED WITH SOME UPPER SHORTWAVE ENERGY...TO TRACK
ACROSS THE LOCAL AREA LATE WEDNESDAY THROUGH THURSDAY
MORNING...IN A CONTINUED PROGRESSIVE WEST SOUTHWESTERLY FLOW. MAIN
AXIS OF INSTABILITY APPEARS FOCUSED JUST EAST OF THE LOCAL AREA
WEDNESDAY AFTERNOON/EVENING...BUT STILL EXPECT ENOUGH INSTABILITY
TO SUPPORT THE DEVELOPMENT OF POTENTIALLY STRONG STORMS ACROSS
THE LOCAL AREA.
.LONG TERM...12Z THURSDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS
WILL BE CHANCES FOR THUNDERSTORMS AND TEMPERATURES.
CONTINUES TO HAVE SEVERAL FAST MOVING SYSTEMS THAT MOVE THROUGH THE
FORECAST AREA DURING THE PERIOD. THE MAIN CONCERN WITH THIS IS
TIMING THE WEAK SYSTEMS AS THEY MOVE THROUGH AND THE MODELS HAVE A
HARD TIME CAPTURING THESE. THERE ARE SMALL CHANCES FOR THUNDERSTORMS
JUST ABOUT ANY PERIOD SOMEWHERE. THE BEST CHANCES WILL BE THURSDAY
AND THURSDAY NIGHT AS A SURFACE LOW AND BOUNDARY MOVE THROUGH THE
FORECAST AREA. FRIDAY AND FRIDAY NIGHT APPEAR DRY WITHOUT MUCH OF A
WAVE MOVING THROUGH AND WEAK SURFACE HIGH PRESSURE.
A STRONGER WAVE AND SURFACE LOW AND BOUNDARY ARE EXPECTED SATURDAY
THROUGH SUNDAY. THIS WILL BE THE BEST CHANCE FOR THUNDERSTORMS
DURING THE PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1227 AM CDT MON APR 30 2012/
AVIATION...06Z KGRI TAF...DETERIORATING CONDS EXPECTED AT KGRI
DURING THE OVERNIGHT HOURS AS DEVELOPING LOW LEVEL STRATUS AND FOG
ARE OVERTAKING THE TERMINAL. LATEST SATELLITE IMAGERY SHOWS STRATUS
BEGINNING TO FILL IN ACROSS MUCH OF SOUTH CENTRAL NEBRASKA...AND
LIFR CIGS AND VSBYS BEGINNING TO BE REPORTED AT SEVERAL SITES.
ONCE THE STRATUS AND FOG SETTLES IN...DO NOT EXPECT MUCH IN THE
WAY OF IMPROVEMENT THROUGH THE REMAINDER OF THE OVERNIGHT
HOURS...AS LIGHT EASTERLY WINDS AND A SATURATED BOUNDARY LAYER AND
STRONG INVERSION WILL HELP MAINTAIN LIFR CONDS THROUGH AROUND
30/14Z. LATEST HRRR INDICATES STRATUS AND FOG WILL LIKELY BEGIN TO
DISSIPATE AROUND THIS TIME...WITH A RETURN TO VFR CIGS AND
VISIBILITIES BY ABOUT 30/16Z. STUCK VERY CLOSE TO THIS
GUIDANCE...AS IT SEEMS TO HAVE A PRETTY GOOD HANDLE ON DEVELOPING
CONDS EARLY THIS MORNING. CANNOT RULE OUT A STRAY SHRA OR TSRA AT
THE TERMINAL LATE TOMORROW AFTERNOON OR EARLY EVENING...BUT DID
NOT MENTION IN CURRENT TAF AS CONFIDENCE IS FAIRLY LOW FOR
SIGNIFICANT COVERAGE. ONCE AGAIN...LATEST GUIDANCE INDICATING A
RETURN TO SOME LLVL STRATUS AND FOG FORMATION TOMORROW NIGHT IN
SOUTHERLY WIND FLOW...BUT WINDS APPEAR MORE ELEVATE...WITH SHOULD
KEEP ANY REDUCED CIGS AND VSBYS JUST BEYOND CURRENT VALID PERIOD
OF TAF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ046-047-
060>062-073>075-083>085.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...ROSSI
LONG TERM...JCB
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1227 AM CDT MON APR 30 2012
.AVIATION...06Z KGRI TAF...DETERIORATING CONDS EXPECTED AT KGRI
DURING THE OVERNIGHT HOURS AS DEVELOPING LOW LEVEL STRATUS AND FOG
ARE OVERTAKING THE TERMINAL. LATEST SATELLITE IMAGERY SHOWS STRATUS
BEGINNING TO FILL IN ACROSS MUCH OF SOUTH CENTRAL NEBRASKA...AND
LIFR CIGS AND VSBYS BEGINNING TO BE REPORTED AT SEVERAL SITES.
ONCE THE STRATUS AND FOG SETTLES IN...DO NOT EXPECT MUCH IN THE
WAY OF IMPROVEMENT THROUGH THE REMAINDER OF THE OVERNIGHT
HOURS...AS LIGHT EASTERLY WINDS AND A SATURATED BOUNDARY LAYER AND
STRONG INVERSION WILL HELP MAINTAIN LIFR CONDS THROUGH AROUND
30/14Z. LATEST HRRR INDICATES STRATUS AND FOG WILL LIKELY BEGIN TO
DISSIPATE AROUND THIS TIME...WITH A RETURN TO VFR CIGS AND
VISIBILITIES BY ABOUT 30/16Z. STUCK VERY CLOSE TO THIS
GUIDANCE...AS IT SEEMS TO HAVE A PRETTY GOOD HANDLE ON DEVELOPING
CONDS EARLY THIS MORNING. CANNOT RULE OUT A STRAY SHRA OR TSRA AT
THE TERMINAL LATE TOMORROW AFTERNOON OR EARLY EVENING...BUT DID
NOT MENTION IN CURRENT TAF AS CONFIDENCE IS FAIRLY LOW FOR
SIGNIFICANT COVERAGE. ONCE AGAIN...LATEST GUIDANCE INDICATING A
RETURN TO SOME LLVL STRATUS AND FOG FORMATION TOMORROW NIGHT IN
SOUTHERLY WIND FLOW...BUT WINDS APPEAR MORE ELEVATE...WITH SHOULD
KEEP ANY REDUCED CIGS AND VSBYS JUST BEYOND CURRENT VALID PERIOD
OF TAF.
&&
.PREV DISCUSSION... /ISSUED 404 PM CDT SUN APR 29 2012/
SHORT TERM...THROUGH MONDAY AFTERNOON. UNFORTUNATELY...CONFIDENCE
IS BELOW AVERAGE DURING THE NEXT 24 HOURS REGARDING SEVERAL
ELEMENTS OF THE FORECAST...INCLUDING CLOUD/FOG TRENDS AND
THUNDERSTORMS/POSSIBLE SEVERE WEATHER CHANCES.
STARTING OFF WITH HERE AND NOW...19Z OBJECTIVE SURFACE ANALYSIS
INDICATES LIGHT EASTERLY BREEZES ACROSS MOST OF THE CWA...FLOWING
OUT OF A SURFACE HIGH CENTERED WELL TO THE NORTHEAST ACROSS THE
GREAT LAKES. THE CWA IS SITUATED WELL NORTH OF THE PRIMARY
REGIONAL SYNOPTIC EAST-WEST BOUNDARY/WARM FRONT...STRETCHED NEAR
THE OK/KS BORDER ACROSS SOUTHERN MO. ALOFT...WATER VAPOR IMAGERY
AND SHORT TERM MODEL DATA INDICATES A CLOSED 500MB LOW DRIFTING
NORTH OUT OF ND INTO CANADA...BUT WITH A TROUGH AXIS TRAILING
SOUTH-SOUTHWEST INTO THE NE/WY/CO BORDER AREA. AHEAD OF THIS
SYNOPTIC SCALE TROUGH AXIS...A LEAD SHORTWAVE IS IN THE PROCESS OF
EXITING THE CWA TO THE EAST...AND IS DRIVING ONGOING SHOWERS
ACROSS SOUTHEAST NEB. VISIBLE SATELLITE IMAGERY CONFIRMS WHY THE
TEMPERATURE FORECAST TODAY HAS BEEN FRUSTRATING...WITH AT LEAST
PARTIAL CLEARING DOMINATING SEVERAL COUNTIES WEST OF HIGHWAY
281...WHILE A SOLID LOW STRATUS DECK HAS STOOD FIRM ACROSS MUCH OF
THE CENTRAL/EAST...WITH A RENEWED NORTHWARD EXPANSION OF LOW
STRATUS NOW EVIDENT OUT OF NORTH CENTRAL KS. AS A RESULT...IT NOW
LOOKS LIKE MANY OF THESE CENTRAL/EASTERN COUNTIES MAY STRUGGLE TO
ATTAIN HIGHS IN THE MID-UPPER 50S...AT LEAST 5-10 DEGREES COOLER
THAN ORIGINALLY EXPECTED.
LATE THIS AFTERNOON THROUGH 00Z...WILL FOCUS THE MAIN CHANCES FOR
POSSIBLE SHOWER/STORM DEVELOPMENT WEST OF A LINE FROM
GREELEY-PLAINVILLE...WHERE CLEARING IS ALLOWING AT LEAST A FEW
HUNDRED J/KG OF 0-1KM MLCAPE TO BUILD. SHORT TERM REFLECTIVITY
PROGS FROM THE HRRR AND 12Z 4KM WRF-NMM SUPPORT THE POSSIBILITY OF
A FEW SHOWERS/STORMS DEVELOPING INTO THESE WESTERN ZONES BEFORE
DARK...AND ALTHOUGH NOT EXPECTING SEVERE WEATHER...A FEW INSTANCES
OF SMALL HAIL/GUSTY WINDS ARE NOT OUT OF THE QUESTION.
TURNING TO THE EVENING 00Z-06Z PERIOD...WILL KEEP LOW-END
THUNDERSTORM CHANCES GOING FOR MUCH OF NORTH CENTRAL KS...AND IN
NEB MAINLY WEST OF A GREELEY-ALMA LINE AS THE MAIN 500MB SHORTWAVE
AXIS SWINGS THROUGH THE CWA. AGAIN...SUPPOSE A FEW INSTANCES OF
SMALL HAIL NOT OUT OF THE QUESTION. FOR THE LATE NIGHT 06Z-12Z
PERIOD...KEPT LOW-END THUNDER CHANCES CONFINED TO A HANDFUL OF
FAR SOUTHWESTERN COUNTIES...IN CLOSEST PROXIMITY TO 850MB THETA-E
ADVECTION TIED TO A MODEST LOW LEVEL JET NOSING OUT OF WESTERN KS.
ALL THIS BEING SAID THOUGH...THE VAST MAJORITY OF THE CWA SHOULD
REMAIN DRY THROUGH THE NIGHT. TURNING TO OTHER OVERNIGHT
ISSUES...AFTER HAVING A ROUND OF LOCALLY DENSE FOG LAST
NIGHT...THERE ARE FAIRLY STRONG INDICATIONS IN NUMERICAL GUIDANCE
AND ALSO VISIBILITY PROBABILITY PROGS FROM THE SREF THAT ANOTHER
FAIRLY WIDESPREAD ROUND OF FOG SHOULD MATERIALIZE TONIGHT...THANKS
TO THE COMBINATION OF LIGHT WINDS AND A SATURATED BOUNDARY LAYER.
CONFIDENCE IN PLACEMENT WAS CERTAINLY NOT HIGH ENOUGH FOR A
HEADLINE YET...BUT WILL INSERT VISIBILITY BELOW 1 MILE INTO THE
GRIDS AND ALSO THE HWO. AS FOR LOW TEMPS...MAY END UP TOO COOL IF
A SOLID STRATUS BLANKET HOLDS FIRM...BUT WILL AIM FOR MID-UPPER
40S MOST AREAS.
TURNING TO MONDAY...OBVIOUSLY FOG COULD BE A CONCERN FOR THE FIRST
FEW HOURS AFTER SUNRISE. THEREAFTER...CONFIDENCE REMAINS UNUSUALLY
LOW IN THUNDERSTORM PROBABILITY/COVERAGE. THE GENERAL BIG PICTURE
INVOLVES A QUASI- ZONAL FLOW ALOFT...AS A LOW AMPLITUDE MID LEVEL
WAVE TRACKS FROM EASTERN CO INTO KS/SOUTHERN NEB. WITH WEAK
CAPPING EVIDENT IN FORECAST SOUNDINGS...AND CONTINUED 850MB
THETA-E ADVECTION...SEVERAL DETERMINISTIC MODELS SUCH AS THE
NAM/ECMWF/GFS ALL BRING STORMS INTO MUCH OF THE SOUTHWEST CWA
ALREADY IN THE MORNING...WHILE ON THE OTHER HAND...THE 4KM WRF-NMM
KEEPS THE MORNING CONVECTION-FREE. THEN DURING THE AFTERNOON...AN
EVEN STRONGER CONVECTIVE SIGNAL DEVELOPS IN SEVERAL DETERMINISTIC
MODELS...WHILE AGAIN THE 4KM REMAINS STRANGELY DRY. ALTHOUGH THE
ULTIMATE EXTENT OF DESTABILIZATION WILL BE STRONGLY INFLUENCED BY
HOW QUICKLY MORNING FOG/STRATUS VACATES...THE 18Z NAM ADVERTISES A
RESPECTABLE SEVERE WEATHER SETUP FOR THE MID-LATE AFTERNOON ACROSS
PARTS OF THE SOUTHERN CWA...BUT ESPECIALLY SOUTHERN ZONES WITH AT
LEAST 1500 J/KG 0-1KM MLCAPE...AND AROUND 40KT OF DEEP LAYER
SHEAR. ALTHOUGH THE OFFICIAL SPC DAY 2 SLIGHT RISK BARELY BRUSHES
THE FAR SOUTHERN CWA...WOULD NOT BE A BIT SURPRISED TO SEE THIS
EXTEND FARTHER NORTH ON THE UPCOMING DAY 1 PRODUCTS...AND WILL
INTRODUCE A SEVERE MENTION FOR HAIL/WIND IN THE HWO EXTENDING INTO
MONDAY EVENING. ALTHOUGH ONLY MODEST SHEAR IN THE LOWEST 1KM
SHOULD LIMIT A TORNADO THREAT...THIS POSSIBILITY IS ALSO NOT OUT
OF THE QUESTION NEAR THE NORTHWARD LIFTING INSTABILITY
GRADIENT/WARM FRONT IN KS ZONES. TEMPERATURE WISE MONDAY...STAYED
CLOSE TO GUIDANCE CONSENSUS...WHICH LOWERED MOST AREAS AT LEAST
2-3 DEGREES FROM PREVIOUS FORECAST INTO MAINLY THE 70-73 RANGE.
WOULD NOT BE SURPRISED THOUGH TO SEE WIDESPREAD CLOUDS ULTIMATELY
KEEP SOME AREAS IN THE 60S...JUST CAN/T SAY WHERE YET.
LONG TERM...MONDAY NIGHT THROUGH SUNDAY. THIS IS VERY COMPLEX
WEATHER PATTERN WITH NUMEROUS WEAK SHORT WAVES CROSSING OUR FORECAST
AREA RESULTING IN ON AND OFF AGAIN SMALL CHANCES FOR SHOWERS AND
THUNDERSTORMS. TEMPERATURES WILL BE WARM FOR THIS TIME OF YEAR WITH
HIGHS IN THE 70S AND 80S THROUGHOUT THE PERIOD. NORMAL HIGHS ARE ONLY
IN THE MID TO UPPER 60S.
MONDAY NIGHT...SEVERAL OF THE THUNDERSTORMS THAT DEVELOP DURING THE
DAY ON MONDAY MAY PERSIST INTO THE EVENING/OVERNIGHT HOURS. A FEW OF
THESE THUNDERSTORMS MAY BE SEVERE...PRIMARILY SOUTH OF INTERSTATE 80.
TUESDAY...TEMPERATURES WARM WITH SOUTHERLY FLOW INTO THE 80S ACROSS
THE ENTIRE FORECAST AREA. THE ATMOSPHERE SHOULD BE PRETTY UNSTABLE BY
AFTERNOON AND A WEAK SHORT WAVE WILL BE MOVING ACROSS THE AREA. AM
ONLY GOING WITH A SLIGHT CHANCE OF THUNDERSTORMS DUE TO THE LIMITED
FORCING...BUT IF STORMS FORM THEY COULD CERTAINLY BE SEVERE GIVEN
APPRECIABLE DEEP LAYER SHEAR AND INSTABILITY.
WEDNESDAY INTO THURSDAY...A SFC FRONTAL BOUNDARY WILL STALL OUT
ACROSS OUR CWA AND MEANDER A BIT BACK AND FORTH ACROSS OUR CWA.
THERE WILL BE AT LEAST MODERATE INSTABILITY AND WITH WEAK UPPER
WAVES PASSING THROUGH WE COULD POP A FEW THUNDERSTORMS. WEAK DEEP
LAYER SHEAR MAY ACTUALLY BE ONE OF THE HINDERING FACTORS FOR SEVERE
WEATHER...BUT MODERATE INSTABILITY MAY BE ENOUGH TO ALLOW A FEW
STORM TO REACH SEVERE WEATHER THRESHOLDS SHOULD THEY FORM.
FRIDAY THROUGH SUNDAY. FRIDAY IS THE ONLY DRY DAY IN THE CURRENT
FORECAST AND EVEN THAT CAN NOT BE GUARANTEED. A STRONG UPPER LEVEL
TROUGH WILL BEGIN TO DEVELOP ACROSS THE WESTERN CONUS BY NEXT WEEKEND
AND WE COULD SEE A FEW CHANCES OF THUNDERSTORMS OUT AHEAD OF THIS
TROUGH...BUT BETTER CHANCES FOR THUNDERSTORMS MIGHT HOLD OFF UNTIL
JUST BEYOND THE END OF THIS FORECAST PERIOD.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ROSSI
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
406 AM EDT MON APR 30 2012
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH ACROSS THE AREA TODAY. AN UPPER LEVEL
WEATHER DISTURBANCE WILL COMBINE WITH A WEAK COLD FRONT TONIGHT TO
PRODUCE SHOWERS AND THUNDERSTORMS. EMBEDDED DISTURBANCES ALOFT
WILL CONTINUE TO RIPPLE ACROSS THE REGION THROUGH MID
WEEK...KEEPING THE THREAT OF SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE USED A BLEND OF THE GFS/ECMWF AS THE NAM-WRF HAS TOO MANY
NEGATIVE FEEDBACK ISSUES DUE TO CONVECTION.
SOUTHWESTERLY FLOW ALOFT IS UNDERWAY THIS MORNING. THIS PATTERN
WILL LIFT A WARM FRONT NORTHWARD ACROSS THE REGION THROUGH EARLY
AFTN. A MUCH WARMER AND MORE HUMID AIRMASS CAN BE EXPECTED IN THE
WAKE OF THIS FRONT...MORE LIKE LATE JUNE WEATHER THAN THE END OF
APRIL. A FEW SHOWERS AND THUNDERSTORMS MAY OCCUR AS THE WARM FRONT
PASSES BY. THEN...EYES TURN TOWARD THE WEST AS A WEAK AREA OF LOW
PRESSURE IS FORECAST TO TRAVERSE ACROSS NRN INDIANA INTO NW OHIO
LATE IN THE DAY. A WEAK COLD FRONT WILL BEGIN TO SAG TOWARD THE NW
CWFA LATE IN THE DAY...INCREASING THE THREAT OF SHOWERS AND STORMS
THERE. FOR THE REMAINDER OF THE AREA...THE MAIN PCPN THREAT IS
EXPECTED THIS EVENING AND OVERNIGHT AND WILL BE DISCUSSED IN THE
SHORT TERM SECTION. CLOUDS AND PCPN WILL KEEP TEMPERATURES COOLER
ACROSS THE NW. HIGHS WILL RANGE FROM THE LOWER 70S FAR NORTHWEST
TO THE MID 80S SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AN EMBEDDED S/WV IS FORECAST TO MOVE ACRS THE REGION OVERNIGHT. IT
IS UNCLEAR IF CONVECTION WILL GET GOING NEAR THE WEAK COLD FRONT
TO OUR NW LATE IN THE DAY...THEN PROPAGATE ESE TOWARD THE BETTER
AXIS OF INSTABILITY OR PERHAPS DEVELOP NEAR A SUBTLE WEAK
PREFRONTAL TROF AS THE LATEST HRRR SUGGESTS. IN EITHER
CASE...CONVECTION SHOULD INCREASE THIS EVENING AS THE S/WV ALOFT
INTERACTS WITH MODERATE INSTABILITY. MODELS SUGGEST THAT THE S/WV
WILL BE ASSOCIATED WITH A 50 TO 60 KNOT MID LVL JET. THE
COMBINATION OF SHEAR AND INSTABILITY SHOULD RESULT IN MUTICELLULAR
CLUSTERS THAT MAY MERGE INTO LINES AND/OR BOWING SEGMENTS. A
SUPERCELL CAN NOT BE RULED OUT EITHER. THE THREAT FOR SOME SEVERE
STORMS WILL BE THERE WITH DAMAGING WIND AND LARGE HAIL BEING THE
PRIMARY SEVERE WEATHER THREATS. WILL EMPHASIZE THIS THREAT IN THE
HWO. STORMS SHOULD HAVE ENOUGH MOVEMENT TO PREVENT A SIGNIFICANT
FLOOD THREAT...BUT WITH PWATS INCREASING TO 1.50 INCHES...HEAVY
RAIN AND LOCALIZED FLOODING ARE A POSSIBILITY. GIVEN STATED
PARAMETERS ABOVE...HAVE CONTINUED WITH LIKELY POPS TONIGHT AS
CONVECTION SHOULD MOVE ESE THROUGH THE OVERNIGHT HOURS. OVERNIGHT
LOWS WILL RANGE FROM THE UPPER 50S TO THE LOWER 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE WEAK COLD FRONT IS FORECAST TO STALL NEAR THE NRN CWFA BY
TUESDAY MORNING. IN A WARM AND UNSTABLE AIRMASS...WILL CONTINUE
WITH CHANCE POPS ON TUESDAY. A BETTER CHANCE OF SHOWERS AND STORMS
MAY OCCUR LATE TUESDAY AFTERNOON AND OVERNIGHT AS ANOTHER EMBEDDED
DISTURBANCE RIPPLES BY ALOFT. THERE APPEARS TO BE LESS SHEAR AND
LOW LEVEL FOCUS WITH THIS ROUND OF PCPN AS WELL AS WEAKER
INSTABILITY SO THE SEVERE THREAT WILL BE MARGINAL. GIVEN
APPRECIABLE PWATS...THE THREAT OF LOCALIZED FLOODING WILL
CONTINUE. HIGHS ON TUESDAY WILL BE A LITTLE COOLER GIVEN CLOUDS
AND SHOULD RANGE FROM THE MID TO UPPER 70S. LOWS TUESDAY NIGHT
WILL FALL INTO THE LOWER 60S.
DEEPER MOISTURE WILL PIVOT NE ON WEDNESDAY AS S/WV MOVES OFF TO
THE EAST. THIS SHOULD ALLOW FOR A DECREASING THREAT OF SHOWERS AND
THUNDERSTORMS FROM WEST TO EAST THROUGH THE DAY. WARM TEMPERATURES
WILL OCCUR WITH HIGHS IN THE LOWER TO MID 80S.
FOR WEDNESDAY NIGHT INTO THURSDAY...MODELS TRY TO BUILD A MID LVL
RIDGE FROM THE SE U.S. NORTH AND WESTWARD INTO THE OHIO VALLEY.
THIS SHOULD GIVE THE REGION A DRY PERIOD ALONG WITH PERHAPS THE
WARMEST TEMPERATURES OF THE WEEK WITH MOST LOCATIONS REACHING INTO
THE MID 80S.
SEVERAL DISTURBANCES ALOFT ARE FORECAST TO RIDE UP THE BACK SIDE
OF THE MID LVL RIDGE THURSDAY NIGHT INTO FRIDAY AND THIS WILL
EVENTUALLY HELP FLATTEN OUT THE RIDGE. THIS WILL ALSO ALLOW FOR A
COLD FRONT TO SAG DOWN FROM THE NORTH AND POSSIBLY LAY OUT ACROSS
OUR AREA FRIDAY INTO SATURDAY. AS THE RIDGE BEGINS TO BREAK
DOWN...WILL ALLOW FOR A CHANCE OF SHOWERS AND THUNDERSTORMS TO
PUSH DOWN INTO OUR AREA THURSDAY NIGHT INTO FRIDAY. HOW LONG THE
PCPN THREAT LINGERS WILL DEPEND ON EXACTLY HOW FAR SOUTH THE
BOUNDARY IS ABLE TO PUSH. FOR NOW WILL SLOWLY TAPER POPS OFF FROM
THE NORTH HEADING INTO SATURDAY. TEMPERATURES WILL ALSO BE
DEPENDENT ON THE PLACEMENT AND TIMING OF THE BOUNDARY. WILL
SLOWLY DECREASE TEMPERATURES THROUGH THE REMAINDER OF THE
EXTENDED PERIOD AS THE UPPER LEVEL RIDGE BEGINS TO WEAKEN AND THE
POSSIBILITY OF SOME PCPN DEVELOPS.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AN ACTIVE PATTERN WILL BE IN PLACE FOR THE NEXT FEW DAYS...LEADING
TO THE POSSIBILITY OF THUNDERSTORMS AT THE TAF SITES.
OVERNIGHT...A NORTHWARD-MOVING WARM FRONT WILL ALLOW FOR A FEW
SCATTERED SHOWERS (AND POSSIBLY THUNDERSTORMS) TO DEVELOP. THIS
DEVELOPMENT IS EXPECTED TO TAKE PLACE BETWEEN NOW AND 12Z...BASED
ON HIGH-RES MODEL DATA AND SIMILAR EXPERIENCES THE PAST TWO
MORNINGS. THIS REPRESENTS ONLY A SMALL CHANCE OF A TAF SITE BEING
IMPACTED...SO VCSH IS BEING USED (AND NOTHING AT ALL FOR
CINCINNATI). THE FRONT WILL BE NORTH OF THE TAF SITES BY
13Z...WITH THE WARM SECTOR ESTABLISHING ITSELF AND PRECIPITATION
CHANCES TEMPORARILY ENDING.
INCREASING SOUTHERLY FLOW WILL TURN SOUTHWEST BY THE MIDDLE OF THE
DAY...WITH GUSTS UP TO AROUND 20 KNOTS. THE CHANCES FOR SHOWERS
AND THUNDERSTORMS WILL BEGIN TO INCREASE BY AFTERNOON...WITH THE
BEST CHANCES COMING DURING THE EVENING HOURS. THERE IS HIGH
CONFIDENCE IN PRECIPITATION AFFECTING THE TAF SITES...WITH THUNDER
EXPECTED. EXACT TIMING IS NOT CERTAIN RIGHT NOW...BUT THERE WILL
LIKELY BE PERIODS OF REDUCED AVIATION CONDITIONS...AND POSSIBLY
STRONG STORMS AS WELL.
OUTLOOK...THUNDERSTORMS POSSIBLE AT TIMES FROM MONDAY NIGHT
THROUGH WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...HICKMAN/JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS TULSA OK
329 AM CDT MON APR 30 2012
.DISCUSSION...
A WEAKENING AREA OF SHOWERS AND THUNDERSTORMS IS PROGRESSING
SOUTHEAST ACROSS NORTHEAST OKLAHOMA EARLY THIS MORNING AND LATEST
RUNS OF THE HRRR SUGGEST THAT AT LEAST A BROKEN BAND OF SHOWERS
AND STORMS WILL MAKE IT THROUGH ALL OF EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS THIS MORNING. RESIDUAL OUTFLOW BOUNDARIES AND
THE OLD FRONTAL BOUNDARY NEAR THE KANSAS AND MISSOURI BORDERS MAY
PROVIDE A FOCUS FOR RENEWED DEVELOPMENT LATER THIS AFTERNOON OR
THIS EVENING BUT BY LATER TONIGHT THE GREATEST CONVECTIVE COVERAGE
IS LIKELY TO BE TO OUR NORTH AND NORTHEAST.
WILL CONTINUE LOW POPS INTO TUESDAY BUT AFTER THAT THE CAPPING
INVERSION STRENGTHENS ENOUGH TO PRECLUDE A MENTION OF CONVECTION.
VERY WARM AND HUMID WEATHER WILL THEN PREVAIL THROUGH AT LEAST
NEXT WEEKEND WITH HIGHS APPROACHING 90 AND LOWS NEAR 70 IN MANY
PLACES.
STAYED CLOSE TO THE WARMER NAM MOS TEMPERATURES THE NEXT COUPLE
DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 80 67 85 68 / 70 20 20 10
FSM 82 66 86 67 / 70 20 10 10
MLC 80 68 84 68 / 50 20 10 10
BVO 78 66 85 67 / 60 30 20 10
FYV 77 63 82 64 / 80 30 20 10
BYV 77 63 82 64 / 70 30 20 10
MKO 80 66 84 67 / 70 20 10 10
MIO 78 66 82 67 / 70 40 20 10
F10 80 67 84 68 / 60 20 10 10
HHW 81 66 84 67 / 50 30 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...14
LONG TERM....05
PLATE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
343 AM CDT MON APR 30 2012
.SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE - LOW TO MEDIUM.
LIGHT WINDS ASSOCIATED WITH WEAK SURFACE TROUGH AND LOW LEVEL
MOISTURE RESULTING IN DENSE FOG OVER ERN IA WHICH IS SPREADING
NORTHEAST INTO FOGGY SUSCEPTIBLE AREAS OF SW CWA. WL HOIST DENSE
FOG ADVY FOR MY FAR SOUTHWEST...WITH THE POTENTIAL FOR DENSE FOG
SPREADING EAST TOWARD RACINE AND KENOSHA EARLY THIS MRNG AS THE
WEAKEST PRESSURE GRADIENT AND LIGHTEST WINDS SPREAD EWD. HRRR ALSO
SHOWING AREAS OF DENSE FOG IN MY FAR SOUTH THRU EARLY MRNG.
ENHANCED SYNOPTIC SCALE FORCING AND LAYER Q-VECTOR CONVERGENCE WILL
CONTINUE TO PUSH TO THE EAST OF SRN WI BY EARLY THIS MRNG ENDING
MOST OF THE -SHRA...HOWEVER FEW -SHRA COULD CLIP THE FAR SOUTHEAST
UNTIL LATER THIS MRNG. SECONDARY WEAK SHORT WAVE UPSTREAM OVER WRN
IA MAY GENERATE SOME PATCHY DRIZZLE AS WELL IN LINGERING LOW LEVEL
RH THIS MRNG. LOW LEVEL WINDS SWITCHING TO THE WEST THIS MRNG WL
ALLOW DRIER AIR ABV INVERSION TO PUSH INTO SRN WI...HOWEVER SHORT
TERM GUIDANCE MAY BE UNDERDOING AMOUNT OF UPSTREAM MOISTURE. KOAX
00Z SOUNDING HAD MOISTURE EXTENDING TO 5K FT. SO THINKING CLOUDS
COULD LINGER FOR MUCH OF THE AFTN...ESPECIALLY IN THE EAST...HOWEVER
CONFIDENCE LOW AT THIS POINT. IF BREAKS WERE TO OCCUR...THEN GOING
TMAX FOR TODAY WL BE TOO LOW.
LOW LEVEL MOISTURE WL LINGER INTO TNGT WITH LIGHT SFC WNDS
CONTINUING. WEAK UPSTREAM WARM AIR ADVECTION WL LIKELY BRING SOME
PATCHY MID-HIGH CLOUDS OVER THE AREA...BUT AT THIS POINT LEANING
TOWARD CLOUD COVER REMAINING SCT-BKN. THIS WOULD ALLOW MORE FOG TO
DEVELOP LATER TNGT.
TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE MEDIUM.
RAIN WILL BE A LITTLE SLOW TO RETURN TO SOUTHERN WI ON TUE GIVEN THE
WEAK RIDGING IN PLACE AND MID LEVEL DRY AIR. MODEL SOUNDINGS SHOW
LIMITED CAPE WITH THE INITIAL PRECIP SO ONLY MENTIONED ISOLATED
THUNDER IN THE FAR SOUTH IN THE AFTERNOON. THE BEST FORCING WILL BE
OVER MN AND CENTRAL IL WHERE THERE IS MORE SHORTWAVE ACTIVITY AND
THE NOSE OF THE LOW LEVEL JET /LLJ/. THE BETTER DYNAMICS FOR
THUNDERSTORM DEVELOPMENT IS EXPECTED TO MOVE ACROSS CENTRAL WI TUE
NIGHT...ESPECIALLY AFTER MIDNIGHT. SUSPECT A MESOSCALE CONVECTIVE
SYSTEM TO DEVELOP UPSTREAM WITH THE NOSE OF THE LLJ AND UPPER
DIVERGENCE DUE TO A COUPLED UPPER JET OVER CENTRAL WI. MAIN THREAT
FOR TUE NIGHT WOULD BE HAIL IN THE ELEVATED CONVECTION. KEPT LIKELY
POPS IN THE NORTHWEST FORECAST AREA AND CHANCE ELSEWHERE.
WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM.
THE SEVERE POTENTIAL IS STILL THERE FOR THIS TIME PERIOD...BUT IT
LOOKS MOST LIKELY AROUND 00Z THU WHEN THE NOSE OF THE LLJ POINTS
INTO SOUTHERN WI AND RIGHT ENTRANCE REGION OF THE UPPER JET BRINGS
THE DEEPER LIFT. A SHORTWAVE IS ALSO PROGGED TO REACH SOUTHERN WI
AROUND THIS TIME AS WELL...WITH THE ECMWF A LITTLE EARLIER THAN THE
GFS. THE FEAR IS THAT WE MAY NOT GET A GOOD ENOUGH TRIGGER FOR
THUNDERSTORMS ANY EARLIER THAN LATE WED AFTERNOON...SO TRIED TO BACK
OFF ON POPS FOR WED. HOWEVER THERE COULD BE SOMETHING TRIGGERING
ALONG ANY OUTFLOW BOUNDARIES FROM PREVIOUS CONVECTION TUE NIGHT.
CAPE VALUES WILL BE HIGH WED AFTERNOON BUT THE BETTER SHEAR FOR
ORGANIZED STORM DEVELOPMENT WILL NOT ARRIVE UNTIL THE LLJ MOVES IN.
HAIL AND WIND WOULD BE THE MAIN THREATS.
SOUTHERN WI WILL REMAIN IN THAT WARM AND UNSTABLE AIR MASS THROUGH
THURSDAY AND ADDITIONAL SHORTWAVES TRACKING ALONG THE WEAKLY
CYCLONIC 500MB FLOW COULD BRING MORE ROUNDS OF SHOWERS AND
THUNDERSTORMS TO SOUTHERN WI WED NIGHT AND THU.
THE SEVERE WEATHER PARAMETER PRODUCT /CWASP/ IN OUR OFFICE
CONTINUES TO SHOW PORTIONS OF SOUTHERN WI IN THE 60 TO 70 PERCENT
RANGE FOR SEVERE WEATHER FOR 00Z THU AND AGAIN 00Z FRI.
TEMPERATURES WILL BE WARM WITH 925MB TEMPS AROUND 19 TO 20C AND
INTERMITTENT DEEPER MIXING EXPECTED TO REACH THAT LEVEL OR HIGHER.
.LONG TERM...
THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM.
THE 850MB BAROCLINIC ZONE WILL REMAIN NEARLY STATIONARY OVER
SOUTHERN WI/NORTHERN IL THROUGH AT LEAST SATURDAY AND THEN SLIP
SOUTHWARD. THE ECMWF IS FASTER WITH THAT IDEA. SHOWER AND
THUNDERSTORM CHANCES WILL CONTINUE ALONG THE BAROCLINIC ZONE IN
SOUTHERN WI...TIED TO THE CONTINUOUS STREAM OF 500MB SHORTWAVES.
THERE WILL BE BREAKS BETWEEN WEATHER SYSTEMS AND POSSIBLY SOME
SUNSHINE AS WELL. TEMPS WILL CONTINUE TO RISE INTO THE 70S THROUGH
SATURDAY.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM TO LOW.
500MB RIDGE AMPLIFYING ACROSS CENTRAL U.S. WILL KEEP THE FOCUS OF
ITS SHORTWAVE ENERGY OVER SOUTHERN WI...THEN SLOWLY SINK SOUTHWARD
WITH THE BAROCLINIC ZONE TOWARD MONDAY AND EARLY NEXT WEEK.
CHANCES FOR SHOWERS WILL CONTINUE.
&&
.AVIATION/12Z TAFS/...LOW CIGS AND VSBYS THIS MRNG WITH POTENTIAL
FOR FOG DROPPING VSBYS BLO 1SM FOR A TIME. AS LOW LEVEL FLOW ABV
INVERSION TURNS TO THE WEST AND INCREASES...LOW LEVEL MIXING OF
DRIER AIR SHOULD GRADUALLY LIFT CIGS TO VFR THIS AFTN OR EVE. LOW
LEVEL MOISTURE TO LINGER INTO TNGT HOWEVER WHICH SHOULD RESULT IN AT
LEAST PATCHY FOG...BUT WL DEPEND ON AMOUNT OF MID/HIGH CLOUDS OVER
AREA AS WARM AIR ADVECTION RECOMMENCES UPSTREAM.
&&
.MARINE...AS EXPECTED HAD A FEW GUSTS INTO THE LOWER 20S OVERNIGHT
AS PRESSURE GRADIENT BRIEFLY TIGHTENED DUE TO WEAK LOW PRESSURE
MOVING THRU CENTRAL MS VALLEY. PRESSURE GRADIENT ALREADY WEAKENING
IN RESPONSE TO SFC LOW APPROACHING ERN IL WITH WEAK NORTHWARD SFC
TROUGH EXTENSION. WINDS WL DMSH TO LIGHT AND VARIABLE FOR MUCH OF
THE DAY INTO TNGT. EXPC AREAS OF FOG THIS MRNG. WL NEED TO WATCH
WEBCAMS FOR POTENTIAL PERIOD OF VSBYS OF 1NM OR LESS IN DECREASING
LOW LEVEL WINDS AND MOIST LOW LEVELS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ062-
067>069.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
TUESDAY THROUGH SUNDAY...MRC
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1115 PM MDT SUN APR 29 2012
.AVIATION...06Z TAFS...VFR CONDITIONS WILL PREVAIL FOR THE MOST PART
ACROSS THE CWA THROUGH MONDAY. THE EXCEPTION WILL BE IN THE FAR
SOUTHEASTERN PANHANDLE EARLY THIS MORNING AT KSNY WHERE IFR CEILINGS
AND VISIBILITIES IN FOG CAN BE EXPECTED FROM ROUGHLY 10Z THROUGH
15Z. SCT LOW CIGS MAY ALSO REACH KAIA. OTHERWISE...MODERATE
SOUTHWEST SURFACE WINDS WILL RETURN ALONG AND WEST OF THE LARAMIE
RANGE LATE THIS MORNING WITH GUSTS UP TO 40 KT IN THIS AREA EXPECTED
THROUGH 01Z TUESDAY...WITH GUSTS 25 TO 30 KTS POSSIBLE FURTHER EAST.
-RJM-
$$
.PREVIOUS DISCUSSION.../ISSUED 908 PM MDT SUN APR 29 2012/
.UPDATE...EVENING WATER VAPOR IMAGERY SHOWED UPPER LEVEL SHORTWAVE
INTO WEST CENTRAL NEBRASKA AND EASTERN COLORADO. ISOLATED TSTORMS
CONTINUED TO DEVELOP ALONG THIS WAVE...WITH DRIER MORE STABLE
SUBSIDENT FLOW IN ITS WAKE THROUGHOUT THE CWA. HENCE...THE REST
OF THIS EVENING WILL BE DRY WITH CLEARING SKIES. THE OVERNIGHT
LOW TEMPERATURE FORECAST IS ON TRACK. GUSTY WEST TO SOUTHWEST
WINDS ALONG AND WEST OF THE LARAMIE RANGE HAVE DECREASED. EXPECT
LIGHT AND VARIABLE WINDS FOR TONIGHT. 00Z NAM AND HRRR ADVECT SOME
LOW LEVEL MOISTURE FROM SOUTHERLY BOUNDARY LAYER FLOW INTO THE
SOUTHERN NEBRASKA PANHANDLE AFTER MIDNIGHT. THIS WILL RESULT
IN PATCHY FOG AND LOW STRATUS.
&&
PREV DISCUSSION... /ISSUED 318 PM MDT SUN APR 29 2012/
SHORT TERM...TONIGHT THROUGH TUESDAY NIGHT...VISIBLE SATELLITE
IMAGERY SHOWS A LOT OF FLAT CUMULUS OVER THE CWA IN THE STABLE AIR
BEHIND THE SHORTWAVE TROUGH AXIS CURRENTLY OVER THE NEBRASKA
PANHANDLE. LEFT A SLIGHT CHANCE OF TSTMS FOR CHEYENNE COUNTY
THROUGH THE EARLY EVENING AS THE CURRENT LAPS ANALYSIS SHOWS
100-200 J/KG OF CAPE OVER THE SOUTHERN NEBRASKA PANHANDLE...HOWEVER
THE SUBSIDENCE BEHIND THE SHORTWAVE IS QUICKLY MOVING EASTWARD.
THE REST OF THE SHORT TERM WILL FEATURE INCREASING WESTERLY WINDS
AND WARMER TEMPS ON MON AND TUES. MID LEVEL FLOW WILL BECOME MORE
ZONAL ON MONDAY WITH STRENGTHENING 700MB FLOW...ESPECIALLY DURING
THE AFTN. WESTERLY WINDS ALONG AND WEST OF THE LARAMIE RANGE WILL
BECOME BREEZY TO WINDY DURING THE AFTN UNDER 35 KT OF 700MB FLOW.
WILL ALSO SEE A WARMING TREND FROM THIS PAST WEEKEND...WITH
WIDESPREAD TEMPS IN THE 70S OVER THE PLAINS...AS 700MB TEMPS RISE
TO AROUND 7C. A LEE TROUGH WILL MAINTAIN DOWNSLOPING OVER THE
PLAINS THROUGH TUES IN ADVANCE OF A SHORTWAVE MOVING THROUGH THE
NORTHERN INTERMOUNTAIN WEST. THE LIFT FROM THIS SHORTWAVE WILL
CAUSE INCREASING CHANCES OF SHOWERS AND ISOLATED TSTMS ON TUES
AFTN...MAINLY ALONG AND WEST OF THE LARAMIE RANGE. COULD HAVE SOME
HIGH BASED TSTMS MOVE OVER THE PLAINS...HOWEVER LLVL MOISTURE AND
INSTABILITY IS LACKING DUE TO THE WESTERLY BOUNDARY LAYER FLOW. AS
THE SHORTWAVE MOVES ACROSS NORTHEAST MT ON TUES NIGHT...700MB
TEMPS DECREASE TO 0-1C OVER THE WESTERN PART OF THE CWA. THIS
MEANS A FEW SNOW SHOWERS COULD FALL OVER THE HIGHER ELEVATIONS OF
THE SIERRA MADRE/SNOWY RANGE IN THE LINGERING MOIST 700-500MB
FLOW.
LONG TERM...WEDNESDAY THROUGH SUNDAY...THIS PART OF THE FORECAST
WILL CONTINUE WITH TEMPERATURES ABOVE NORMAL THROUGH AT LEAST THE
EARLY PART OF NEXT WEEKEND. THERE WILL ALSO BE AT LEAST A SMALL
THREAT OF ALMOST DAILY SHOWERS AND LATE DAY THUNDERSTORMS. HEIGHTS
ALOFT SLOWLY RISE AND FLOW SLOWLY BACKS OVER THE ROCKIES THROUGH
SATURDAY. THE FAIRLY FLAT AND PROGRESSIVE FLOW ALOFT WILL BECOME
MORE AMPLIFIED THROUGH NEXT WEEKEND. A DEEP TROUGH DEVELOPS ALONG
THE WEST COAST LATE IN THE WEEK WITH AN UPPER LOW EVENTUALLY
CLOSING OFF ON SATURDAY OVER NORTHERN CALIFORNIA. MODELS DIFFER IN
THE PLACEMENT OF THE TROUGH AND UPPER LOW OVER THE WEEKEND. THE
ECMWF HAS BEEN SLOWER THAN THE GFS DURING THAT TIME...BUT THE 12Z
ECMWF IS FASTER WITH THE LARGE UPPER LOW OVER IDAHO 12Z SUNDAY.
WILL CONTINUE TO LEAN MORE TOWARDS THE SLOWER AND DEEPER 00Z ECMWF
PLACEMENT FOR THIS FORECAST. SHORTWAVE TROUGHS WITHIN THE FLOW
ALOFT WILL MOVE ACROSS THE REGION THROUGH SATURDAY WITH THE ECMWF
CONTINUING TO MOVE AN OLD UPPER LOW TO THE NORTHEAST AND OVER THE
CWA SATURDAY AND SATURDAY NIGHT. THE SHORTWAVE TROUGHS WILL MOVE
SEVERAL SURFACE BOUNDARIES ACROSS THE CWA THROUGH THIS PERIOD. THE
BOUNDARIES...SHORTWAVE TROUGHS AND FAVORABLE 300 MB JET LOCATIONS
AT TIMES WILL PRODUCE THE SHOWERS AND LATE DAY STORMS OVER
PORTIONS OF THE CWA. THE MODELS...ESPECIALLY THE ECMWF...DRY THE
ATMOSPHERE OVER THE CWA SOME ON THURSDAY AND EVEN MORE SO FOR
FRIDAY. FOR NOW WILL TRY TO DIFFERENTIATE THE BETTER PERIODS FOR
PRECIPITATION FROM THE PERIODS THAT CURRENTLY DO NOT LOOK AS
FAVORABLE. SO WILL HAVE THE HIGHEST POPS OVER THE CWA WEDNESDAY
AFTERNOON AND EARLY NIGHT AND A MINIMUM FOR FRIDAY. POPS WILL
AGAIN INCREASE OVER THE REGION FOR NEXT WEEKEND AS MOISTURE AND
INSTABILITY INCREASE AHEAD OF THE UPSTREAM STORM SYSTEM. SATURDAY
AFTERNOON AND EVENING MAY BE A POTENTIAL SEVERE WEATHER DAY...WITH
NEXT SUNDAY COOLER AND SHOWERY.
&&
FIRE WEATHER...THE RECENT RAINFALL OVER THE PAST WEEK ACROSS
SOUTHEAST WYOMING AND NEBRASKA PANHANDLE IS CONTRIBUTING TO A
GREEN UP OVER MOST OF THE AREA. THERE IS AN ELEVATED FIRE DANGER
THREAT ON MONDAY AFTERNOON DUE TO THE COMBINATION OF WARM AND DRY
CONDITIONS AND INCREASING WEST TO SOUTHWEST WINDS. MINIMUM
AFTERNOON RELATIVE HUMIDITIES WILL BE AROUND 15 PERCENT OVER
SOUTHEAST WYOMING TO THE EAST OF THE LARAMIE RANGE. THE NEBRASKA
PANHANDLE WILL SEE AFTERNOON HUMIDITY VALUES IN THE 15 TO 20
PERCENT RANGE. WITH A LEE TROUGH DEVELOPING OVER THE
PLAINS...WESTERLY WINDS WILL INCREASE TO 15 TO 20 MPH WITH GUSTS
TO 30 MPH...ESPECIALLY ALONG AND WEST OF THE LARAMIE RANGE. WHILE
THE WEATHER CONDITIONS WARRANT AN ELEVATED FIRE DANGER THREAT...IT
WILL BE TEMPERED BY THE RECENT GREEN UP.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&
$$
SHORT TERM...JAMSKI
AVIATION...RJM
LONG TERM...WEILAND
FIRE WEATHER...FINCH
AREA FORECAST DISCUSSION
NWS MIAMI FL
945 AM EDT MON APR 30 2012
.UPDATE...
MODERATE TO HEAVY RAIN SHOWERS CONTINUE TO PUSH WEST ACROSS THE
ATLANTIC WATERS AND SOUTH FLORIDA PENINSULA. LATEST RADAR TRENDS
DO SHOW SOME ENHANCEMENT OF HEAVIER RAIN SHOWERS WITH GUSTY WINDS
AND BRIEF HEAVY DOWNPOURS. LATEST LAPS DATA SHOW 50-55 KT 700 MB
WINDS STREAMING ACROSS PALM BEACH COUNTY. HOWEVER...THE 10Z HRRR
ANALYSIS...WHICH HAS PERFORMED WELL LATELY...SHOWS MOST OF THE
SHOWER AND THUNDERSTORM ACTIVITY GETTING SHUNTED SOUTH AND WEST
AROUND THE KEYS ALONG WITH THE MOVEMENT OF THE TROUGH. ONGOING
FORECAST PARAMETERS LOOK GOOD SO NO UPDATES ARE PLANNED ATTM.
&&
.PREV DISCUSSION... /ISSUED 649 AM EDT MON APR 30 2012/
AVIATION...12Z ISSUANCE...A SURFACE TROUGH JUST OFF THE
SOUTHEAST FLORIDA COAST WILL PUSH SLOWLY WEST TODAY WHILE A MID
LEVEL LOW ALSO RETROGRADES ACROSS THE REGION. SCATTERED TO
NUMEROUS SHOWERS AND PERHAPS A FEW TSRA EXPECTED, ESPECIALLY FROM
KFXE AND POINTS SOUTH AND WEST. VCSH ARE WARRANTED FOR ALL SITES
THROUGH THE DAY, WITH TEMPO GROUPS ASSIGNED FOR RA AND MVFR
CEILINGS/VISIBILITIES. SOME HEAVIER ACTIVITY MAY ALSO RESULT IN
BRIEF IFR CONDITIONS. SURFACE WINDS WILL ALSO BE A CONCERN WITH
SUSTAINED SPEEDS AROUND 20 KNOTS AND FREQUENT HIGHER GUSTS.
PREV DISCUSSION... /ISSUED 357 AM EDT MON APR 30 2012/
DISCUSSION...
WATER VAPOR IMAGERY FROM EARLY THIS MORNING SHOWED DRY AIR HAD
WRAPPED INTO THE MID/UPPER LOW LOCATED OVER SOUTH FLORIDA. THIS HAS
PREVENTED THE HEAVY RAIN THAT WAS EXPECTED ACROSS THE REGION
OVERNIGHT...AND INSTEAD LIGHT TO MODERATE SHOWERS WERE MOVING ACROSS
SOUTH FLORIDA. MOST MODEL GUIDANCE HAS BEEN EXTREMELY
INCONSISTENT...FLIPPING BACK AND FORTH EVEN IN THE VERY SHORT TERM.
COMPLETELY TOSSED OUT THE 00Z GFS AS IT IS SUFFERING FROM CONVECTIVE
FEEDBACK. IT HAS A BLOWUP NEAR NAPLES IN THE NEXT COUPLE
HOURS...WHICH STEALS ALL THE MOISTURE FROM THE ATLANTIC.
THE HRRR SHOWS THE AREA OF HEAVIER RAIN THAT WAS DEVELOPING TO THE
EAST SOUTHEAST OF THE KEYS POSSIBLY MOVING NORTHWARD INTO MIAMI DADE
COUNTY OVER THE NEXT SEVERAL HOURS AND THEN MOVING TO THE WEST AND
OUT OF THE REGION AN HOUR OR TWO AFTER SUNRISE. THE MODEL SHOWS THAT
IS PRETTY MUCH THE ENTIRE BALL GAME...WITH EVERYTHING BASICALLY
DISSIPATING AFTER THAT AND ONLY LIGHT TO MODERATE RAIN THROUGHOUT
THE DAY. THIS SCENARIO IS DEFINITELY POSSIBLE...MUCH LIKE WHAT
HAPPENED YESTERDAY. HOWEVER...IN THEORY...WITH THE UPPER LOW
RETROGRADING TO THE WEST AND THE INVERTED TROUGH MOVING TO THE
WEST ACROSS THE REGION...THE CHANCES FOR HEAVIER RAIN SHOULD
ACTUALLY BE BETTER TODAY THAN YESTERDAY. THE ECMWF FOLLOWS THIS
SCENARIO...WITH HEAVIER RAIN MOVING INTO THE COASTLINE BETWEEN 12
AND 18Z AND THEN CONTINUING THROUGH MUCH OF THE DAY. SO ANOTHER
1-3 INCHES OF RAIN IS EXPECTED ALONG THE COAST TODAY...WITH
LOCALLY HIGHER AMOUNTS. THOUGHT ABOUT DROPPING THE FLOOD WATCH
FOR PALM BEACH COUNTY AS MOST OF THE HEAVY RAIN SHOULD BE ACROSS
BROWARD AND MIAMI DADE COUNTY. HOWEVER...SINCE GUIDANCE HAS BEEN
INCONSISTENT AT BEST AND THE SOUTHEAST PORTION OF PALM BEACH
COUNTY COULD RECEIVE HEAVY RAIN...LEFT THE FLOOD WATCH IN PLACE.
BREEZY TO WINDY CONDITIONS ARE EXPECTED TODAY...ESPECIALLY TOWARDS
THE EAST COAST...WITH WINDS GUSTING TO 25-35 MPH THROUGH THE DAY. IF
THERE ARE ANY HEAVIER SHOWERS OR THUNDERSTORMS...WIND GUSTS UP TO 50
MPH WILL BE POSSIBLE. UNDERCUT GUIDANCE FOR HIGH TEMPERATURES TODAY
BY 2 TO 8 DEGREES ACROSS THE REGION...CUTTING TEMPS THE MOST ACROSS
THE GULF COAST. GUIDANCE TEMPS IN THE LOW TO MID 80S SEEMED
UNREASONABLE FOR NAPLES DUE TO THE CLOUD COVER AND RAINFALL
EXPECTED TODAY...AND TEMPERATURES MAY ACTUALLY NOT RISE OUT OF THE
LOWER 70S. ACROSS MOST OF THE REGION...TEMPERATURES MORE THAN
LIKELY WILL NOT CHANGE BY MORE THAN A COUPLE DEGREES FROM WHAT
WILL BE OBSERVED THIS MORNING.
THE SHARP INVERTED TROUGH IS EXPECTED TO MOVE WELL OUT INTO THE GULF
OVERNIGHT TONIGHT...BUT ONSHORE FLOW AND A STREAM OF DEEP MOISTURE
WILL STAY OVER THE REGION AS HIGH PRESSURE HOLDS STEADY OVER THE
WESTERN ATLANTIC. WITH A RELATIVELY TIGHT GRADIENT
REMAINING...SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED ALONG THE
EAST COAST AND DEEP SOUTH FLORIDA. HIGH PRESSURE IS EXPECTED TO
REMAIN OVER THE WESTERN ATLANTIC THROUGH MIDWEEK...WITH AROUND 20
KNOT WINDS CONTINUING OVER THE LOCAL ATLANTIC WATERS. SO AT LEAST
SCATTERED SHOWERS WILL CONTINUE...ESPECIALLY IN THE OVERNIGHT
HOURS DUE TO THE SPEED SHEAR ALONG THE COAST. HIGH PRESSURE IS
EXPECTED TO WEAKEN THURSDAY INTO THE WEEKEND...AND RAIN CHANCES
ARE EXPECTED TO SLOWLY DECREASE THROUGH THIS PERIOD. AS THE RAIN
CHANCES DECREASE...TEMPERATURES WILL WARM BACK INTO THE 80S TO
AROUND 90 ACROSS THE NORTHWEST INTERIOR.
AVIATION...
06Z ISSUANCE...A SURFACE TROUGH OF LOW PRESSURE CONTINUES TO MOVE
SLOWLY WEST NEAR THE SOUTHEAST FLORIDA COAST. MEANWHILE, THE
ASSOCIATED MID LEVEL LOW IS LOCATED OVER FAR SOUTH FLORIDA. WITH
PERSISTENT AND STRONG EASTERLY FLOW CONTINUING, WE EXPECT
SCATTERED TO NUMEROUS SHOWERS TO PREVAIL, ALONG WITH PERHAPS A FEW
TSRA AS WELL. TEMPO GROUPS TO INDICATE MVFR CEILINGS ARE
WARRANTED, ALTHOUGH EVEN IFR CONDITIONS COULD BRIEFLY OCCUR IN
HEAVIER SHRA. EASTERLY WINDS WILL PERSIST THROUGH THE TAF PERIOD.
SUSTAINED SURFACE WINDS WILL AVERAGE 15-20 KNOTS WITH FREQUENT
HIGHER GUSTS.
MARINE...
DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 73 81 74 / 60 30 30 20
FORT LAUDERDALE 76 73 79 74 / 70 50 40 40
MIAMI 76 73 79 74 / 70 60 50 40
NAPLES 77 70 81 70 / 50 30 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR COASTAL BROWARD-
COASTAL MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-
INLAND MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM
BEACH.
HIGH RIP CURRENT RISK THROUGH TUESDAY EVENING FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR BISCAYNE BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
910 AM EDT MON APR 30 2012
.UPDATE (REST OF TODAY AND TONIGHT)...
13Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS A SOMEWHAT UNAMPLIFIED
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS THIS MORNING. NORTHERN
STREAM FLOW ARRIVES OVER THE PACIFIC NORTHWEST COAST AND REMAINS
RATHER ZONAL OVER THE INTER-MOUNTAIN WEST/HIGH PLAINS. THE FLOW THEN
BENDS NORTHWARD INTO SHARP RIDGING OVER THE NORTHEASTERN STATES.
WEAK IMPULSES RIDING ALONG WITH THE FLOW HAVE BEEN PRODUCING
PERIODIC BURST OF CONVECTION OVER THE MID-SECTION OF THE COUNTY AS
THEY EJECT OUT OVER THE CENTRAL PLAINS. MORE OF THESE CONVECTIVE
BURSTS ARE EXPECTED TODAY WITH LOCALLY STRONG STORMS AND FLOODING
RAINFALL. CLOSER TO HOME...THE UPPER LEVEL PATTERN IS SIMILAR TO
WHAT HAS BEEN OBSERVED FOR THE PAST COUPLE OF DAYS. UPPER LEVEL
RIDGING REMAINS IN PLACE FROM THE NORTH-CENTRAL GULF COAST TO THE
CAROLINAS...WHILE AN UPPER LEVEL DISTURBANCE SPINS FROM THE FL
STRAITS TO THE BAHAMAS. DEEP LAYER MOISTURE THIS MORNING IS CONFINED
IN CLOSE PROXIMITY TO THIS UPPER DISTURBANCE...GENERALLY SOUTH AND
EAST OF THE TAMPA BAY AREA. 12Z KTBW SOUNDING WAS SIGNIFICANTLY
DRIER THAN WHAT WAS OBSERVED AT KMFL WHERE THE COLUMN WAS NEARLY
SATURATED BELOW 400MB. THE DEEP LAYER MOISTURE IS NOT HAVING MUCH
NORTHWARD PROGRESS AS IT RUNS INTO THE SYNOPTIC SUPPRESSION
UNDERNEATH THE UPPER RIDGE. IN FACT...NWP GUIDANCE IN AGREEMENT IN A
FURTHER RETREAT SOUTH AND EAST OF THE MID/HIGH LEVEL MOISTURE
THROUGH THE DAY. WITH THIS IN MIND...THE HIGHEST DEGREE OF CLOUDS
WILL BE SOUTH AND EAST OF THE BAY AREA...WITH MOSTLY SUNNY SKIES
FURTHER TO THE NORTH.
AT THE SURFACE...FORECAST AREA REMAINS WEDGED BETWEEN THE
SUBTROPICAL RIDGE AXIS TO OUR NORTH AND AN INVERTED SURFACE TROUGH
SLOWLY MOVING WESTWARD ACROSS THE FL STRAITS/SOUTH FLORIDA
PENINSULA. THIS STUBBORN TROUGH CONTINUES TO SUPPLY THE LOW LEVEL
FOCUS FOR ASCENT WITH SCT-NMRS SHOWERS OVER THE FAR SOUTHERN PORTION
OF THE PENINSULA.
INHERITED FORECAST APPEARS ON TRACK AND WILL ONLY MAKE A FEW MINOR
ADJUSTMENTS...MAINLY TO THE TIMING OF ANY SHOWER ACTIVITY. SIMILAR
TO PREVIOUS DAYS...WILL LIKELY NEED TO WAIT SEVERAL HOURS FOR ANY
DIFFERENTIAL HEATING FOR FORCE THE ISOLATED/WDLY SCT SHOWERS OVER
OUR AREA. HAVE REMOVED MENTION OF SHOWERS IN THE FORECAST PRIOR TO
1-2PM. TEMPERATURE FORECAST LOOKS GOOD BASED ON THE LATEST EARLY
MORNING VIS SATELLITE IMAGERY. MOST DAYTIME INSOLATION AND DEEP
LAYER SUPPRESSION WILL BE OVER THE NORTHERN ZONES RESULTING IN
TEMPERATURES WELL INTO THE 80S TO LOWER 90S. UNDER THE MORE
PRONOUNCED CLOUD CANOPY TO THE SOUTH TEMPERATURES WILL BE SEVERAL
DEGREES COOLER.
SYNOPTIC PATTERN HOLDS THROUGH TONIGHT KEEPING CHANCES FOR SHOWERS
CONFINED TO THE FAR SOUTHERN PORTIONS OF THE PENINSULA. ANOTHER WARM
NIGHT ON TAP WITH ABUNDANT ATLANTIC MOISTURE HELPING TO HOLD LOW
TEMPERATURES IN THE UPPER 60S TO LOWER 70S.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL ACROSS THE REGION TODAY. MOSTLY CLEAR
SKIES THIS MORNING FROM TPA TO FMY...WITH SCT STRATO-CU 040-050
DEVELOPING BY THIS AFTERNOON. CHANCE OF A SHOWER MAINLY VCNTY
PGD/RSW/FMY WITH LCL MVFR CIGS/VSBYS. DECREASING CLOUDINESS AFTER
SUNSET WITH THE LOSS OF DAYTIME HEATING.
&&
.MARINE...
INCREASING EASTERLY WINDS WITH TROUGH OF LOW PRESSURE MOVING SOUTH
OF THE AREA OVER THE NEXT FEW DAYS. SMALL CRAFT ADVISORY IN THE
SOUTHERN WATERS WILL CONTINUE AND WILL EXPAND THE ADVISORY INTO
THE CENTRAL WATERS BEGINNING TONIGHT AS THE WINDS INCREASE. SEAS
BUILDING IN THE OFFSHORE WATERS IN RESPONSE TO HIGHER WINDS. LOW
WILL EXIT WESTWARD INTO THE GULF BY WEDNESDAY BUT SOMEWHAT
ELEVATED WINDS OVER THE GULF WILL PERSIST THROUGH THE LATE WEEK
PERIOD AS HIGH PRESSURE SLIDES SOUTH OFF THE MID ATLANTIC COAST
AND KEEPS A TIGHTER PRESSURE GRADIENT IN PLACE. THE RIDGE WILL
GRADUALLY BUILD INTO THE GULF BY THE WEEKEND AND BRING LIGHTER
WINDS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 87 71 86 72 / 10 10 10 15
FMY 83 70 86 70 / 35 30 40 15
GIF 87 68 86 69 / 10 10 15 10
SRQ 87 70 85 69 / 20 15 25 15
BKV 90 66 89 66 / 5 10 10 15
SPG 87 74 84 74 / 10 10 20 15
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY FROM NOON TODAY TO 7 PM EDT THIS
EVENING FOR CHARLOTTE-DE SOTO-HARDEE-HIGHLANDS-
HILLSBOROUGH-LEE-MANATEE-PINELLAS-POLK-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 8 AM EDT
TUESDAY FOR ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR BONITA
BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM.
&&
$$
UPDATE...MROCZKA
AVIATION...OGLESBY
AREA FORECAST DISCUSSION
NWS MIAMI FL
649 AM EDT MON APR 30 2012
.AVIATION...12Z ISSUANCE...A SURFACE TROUGH JUST OFF THE
SOUTHEAST FLORIDA COAST WILL PUSH SLOWLY WEST TODAY WHILE A MID
LEVEL LOW ALSO RETROGRADES ACROSS THE REGION. SCATTERED TO
NUMEROUS SHOWERS AND PERHAPS A FEW TSRA EXPECTED, ESPECIALLY FROM
KFXE AND POINTS SOUTH AND WEST. VCSH ARE WARRANTED FOR ALL SITES
THROUGH THE DAY, WITH TEMPO GROUPS ASSIGNED FOR RA AND MVFR
CEILINGS/VISIBILITIES. SOME HEAVIER ACTIVITY MAY ALSO RESULT IN
BRIEF IFR CONDITIONS. SURFACE WINDS WILL ALSO BE A CONCERN WITH
SUSTAINED SPEEDS AROUND 20 KNOTS AND FREQUENT HIGHER GUSTS.
&&
.PREV DISCUSSION... /ISSUED 357 AM EDT MON APR 30 2012/
DISCUSSION...
WATER VAPOR IMAGERY FROM EARLY THIS MORNING SHOWED DRY AIR HAD
WRAPPED INTO THE MID/UPPER LOW LOCATED OVER SOUTH FLORIDA. THIS HAS
PREVENTED THE HEAVY RAIN THAT WAS EXPECTED ACROSS THE REGION
OVERNIGHT...AND INSTEAD LIGHT TO MODERATE SHOWERS WERE MOVING ACROSS
SOUTH FLORIDA. MOST MODEL GUIDANCE HAS BEEN EXTREMELY
INCONSISTENT...FLIPPING BACK AND FORTH EVEN IN THE VERY SHORT TERM.
COMPLETELY TOSSED OUT THE 00Z GFS AS IT IS SUFFERING FROM CONVECTIVE
FEEDBACK. IT HAS A BLOWUP NEAR NAPLES IN THE NEXT COUPLE
HOURS...WHICH STEALS ALL THE MOISTURE FROM THE ATLANTIC.
THE HRRR SHOWS THE AREA OF HEAVIER RAIN THAT WAS DEVELOPING TO THE
EAST SOUTHEAST OF THE KEYS POSSIBLY MOVING NORTHWARD INTO MIAMI DADE
COUNTY OVER THE NEXT SEVERAL HOURS AND THEN MOVING TO THE WEST AND
OUT OF THE REGION AN HOUR OR TWO AFTER SUNRISE. THE MODEL SHOWS THAT
IS PRETTY MUCH THE ENTIRE BALL GAME...WITH EVERYTHING BASICALLY
DISSIPATING AFTER THAT AND ONLY LIGHT TO MODERATE RAIN THROUGHOUT
THE DAY. THIS SCENARIO IS DEFINITELY POSSIBLE...MUCH LIKE WHAT
HAPPENED YESTERDAY. HOWEVER...IN THEORY...WITH THE UPPER LOW
RETROGRADING TO THE WEST AND THE INVERTED TROUGH MOVING TO THE
WEST ACROSS THE REGION...THE CHANCES FOR HEAVIER RAIN SHOULD
ACTUALLY BE BETTER TODAY THAN YESTERDAY. THE ECMWF FOLLOWS THIS
SCENARIO...WITH HEAVIER RAIN MOVING INTO THE COASTLINE BETWEEN 12
AND 18Z AND THEN CONTINUING THROUGH MUCH OF THE DAY. SO ANOTHER
1-3 INCHES OF RAIN IS EXPECTED ALONG THE COAST TODAY...WITH
LOCALLY HIGHER AMOUNTS. THOUGHT ABOUT DROPPING THE FLOOD WATCH
FOR PALM BEACH COUNTY AS MOST OF THE HEAVY RAIN SHOULD BE ACROSS
BROWARD AND MIAMI DADE COUNTY. HOWEVER...SINCE GUIDANCE HAS BEEN
INCONSISTENT AT BEST AND THE SOUTHEAST PORTION OF PALM BEACH
COUNTY COULD RECEIVE HEAVY RAIN...LEFT THE FLOOD WATCH IN PLACE.
BREEZY TO WINDY CONDITIONS ARE EXPECTED TODAY...ESPECIALLY TOWARDS
THE EAST COAST...WITH WINDS GUSTING TO 25-35 MPH THROUGH THE DAY. IF
THERE ARE ANY HEAVIER SHOWERS OR THUNDERSTORMS...WIND GUSTS UP TO 50
MPH WILL BE POSSIBLE. UNDERCUT GUIDANCE FOR HIGH TEMPERATURES TODAY
BY 2 TO 8 DEGREES ACROSS THE REGION...CUTTING TEMPS THE MOST ACROSS
THE GULF COAST. GUIDANCE TEMPS IN THE LOW TO MID 80S SEEMED
UNREASONABLE FOR NAPLES DUE TO THE CLOUD COVER AND RAINFALL
EXPECTED TODAY...AND TEMPERATURES MAY ACTUALLY NOT RISE OUT OF THE
LOWER 70S. ACROSS MOST OF THE REGION...TEMPERATURES MORE THAN
LIKELY WILL NOT CHANGE BY MORE THAN A COUPLE DEGREES FROM WHAT
WILL BE OBSERVED THIS MORNING.
THE SHARP INVERTED TROUGH IS EXPECTED TO MOVE WELL OUT INTO THE GULF
OVERNIGHT TONIGHT...BUT ONSHORE FLOW AND A STREAM OF DEEP MOISTURE
WILL STAY OVER THE REGION AS HIGH PRESSURE HOLDS STEADY OVER THE
WESTERN ATLANTIC. WITH A RELATIVELY TIGHT GRADIENT
REMAINING...SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED ALONG THE
EAST COAST AND DEEP SOUTH FLORIDA. HIGH PRESSURE IS EXPECTED TO
REMAIN OVER THE WESTERN ATLANTIC THROUGH MIDWEEK...WITH AROUND 20
KNOT WINDS CONTINUING OVER THE LOCAL ATLANTIC WATERS. SO AT LEAST
SCATTERED SHOWERS WILL CONTINUE...ESPECIALLY IN THE OVERNIGHT
HOURS DUE TO THE SPEED SHEAR ALONG THE COAST. HIGH PRESSURE IS
EXPECTED TO WEAKEN THURSDAY INTO THE WEEKEND...AND RAIN CHANCES
ARE EXPECTED TO SLOWLY DECREASE THROUGH THIS PERIOD. AS THE RAIN
CHANCES DECREASE...TEMPERATURES WILL WARM BACK INTO THE 80S TO
AROUND 90 ACROSS THE NORTHWEST INTERIOR.
AVIATION...
06Z ISSUANCE...A SURFACE TROUGH OF LOW PRESSURE CONTINUES TO MOVE
SLOWLY WEST NEAR THE SOUTHEAST FLORIDA COAST. MEANWHILE, THE
ASSOCIATED MID LEVEL LOW IS LOCATED OVER FAR SOUTH FLORIDA. WITH
PERSISTENT AND STRONG EASTERLY FLOW CONTINUING, WE EXPECT
SCATTERED TO NUMEROUS SHOWERS TO PREVAIL, ALONG WITH PERHAPS A FEW
TSRA AS WELL. TEMPO GROUPS TO INDICATE MVFR CEILINGS ARE
WARRANTED, ALTHOUGH EVEN IFR CONDITIONS COULD BRIEFLY OCCUR IN
HEAVIER SHRA. EASTERLY WINDS WILL PERSIST THROUGH THE TAF PERIOD.
SUSTAINED SURFACE WINDS WILL AVERAGE 15-20 KNOTS WITH FREQUENT
HIGHER GUSTS.
MARINE...
DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 73 81 74 / 60 30 30 20
FORT LAUDERDALE 76 73 79 74 / 70 50 40 40
MIAMI 76 73 79 74 / 70 60 50 40
NAPLES 77 70 81 70 / 50 30 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH THROUGH THIS EVENING FOR COASTAL BROWARD-COASTAL
MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-INLAND
MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM BEACH.
HIGH RIP CURRENT RISK THROUGH TUESDAY EVENING FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR BISCAYNE BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
AVIATION...14/MJB
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
731 AM EDT MON APR 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE FAIR WEATHER THROUGH THURSDAY. AN UPPER
LEVEL DISTURBANCE AND INCREASING ATMOSPHERIC MOISTURE MAY PROVIDE A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...OBSERVATIONS INDICATE WIDESPREAD VISIBILITIES BELOW ONE
HALF MILE ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN MIDLANDS.
ISSUED DENSE FOG ADVISORY.
PREVIOUS DISCUSSION...
AREA OF STRATUS ENVELOPING THE COAST AND PEE DEE REGION EARLY
THIS MORNING. GFS/NAM AND RUC MODELS INDICATE LOW CLOUDS MOVING
WESTWARD INTO THE MIDLANDS THOUGH SUNRISE. WILL KEEP MENTION OF
PATCHY FOG IN THE FORECAST...BUT GIVEN LIGHT SOUTHEAST WIND FLOW
EXPECT MORE STRATUS THAN FOG. LOW CLOUDS/FOG IS EXPECTED TO CLEAR
AROUND MID-MORNING. UPPER LEVEL RIDGING WAS OVER THE REGION THIS
MORNING. SURFACE HIGH PRESSURE STRETCHED FROM EASTERN CANADA DOWN
THE EAST COAST TO THE GULF OF MEXICO. WARM AND DRY FORECAST
EXPECTED TODAY AND TONIGHT AS HIGH PRESSURES REMAINS IN CONTROL.
WENT SLIGHTLY ABOVE MOS GUIDANCE FOR AFTERNOON HIGHS...GIVEN ITS
COOL BIAS PAST FEW DAYS. TEMPERATURE WILL BE ABOVE NORMAL IN THE
MID 80S TO LOWER 90 THIS AFTERNOON. LOWS TONIGHT WILL BE
CONSISTENT IN THE LOW TO MID 60S. EXPECT LATE NIGHT/EARLY MORNING
LOW CLOUDS TO DEVELOP AGAIN TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
THE MID AND UPPER LEVEL RIDGE REMAIN OVER THE REGION THROUGH
THURSDAY NIGHT. THIS ALONG WITH A RELATIVELY DRY ATMOSPHERE WILL
SUPPRESS CONVECTION. THE CENTER OF SURFACE HIGH PRESSURE WILL
LINGER IN THE WESTERN ATLANTIC...YET CONTINUE TO CONTROL OUR
WEATHER. STILL EXPECT ABOVE NORMAL TEMPERATURES WITH AFTERNOON
HIGHS IN THE MID 80S TO LOWER 90S AND LOWS IN THE LOWER TO MIDDLE
60S.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
GFS/ECMWF INDICATE UPPER RIDGE NEAR THE SOUTHEAST COAST TO MOVE
EAST...WHILE UPPER ENERGY OVER FLORIDA SLOWLY SHIFTS
NORTH...JOINED BY OTHER IMPULSES SHIFTING EAST FROM THE EASTERN
PACIFIC...TO PROVIDE SOME TROUGHINESS AND POSSIBLY A CLOSED LOW
OVER THE DEEP SOUTH...MAINLY TO OUR WEST FOR THE END OF THE WEEK.
THIS ALONG WITH MOISTURE RETURN WILL BRING A CHANCE FOR
SHOWERS/THUNDERSTORMS MAINLY TO OUR WEST. ACCEPTED GUIDANCE
CONSENSUS OF SLIGHT CHANCE POPS FRI/SAT.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
FOG/STRATUS CURRENTLY OVER PORTIONS OF THE FORECAST AREA...WITH
LIFR CONDITIONS CURRENTLY AT OGB/CUB. LOWER CIGS...AND POSSIBLY
LOWER VSBYS...WILL MOVE INTO CAE/AGS/DNL IN THE NEAR TERM...THEN
FOG/STRATUS TO DISSIPATE LATER THIS MORNING. AFTERWARD...VFR
CONDITIONS EXPECTED FOR THE REMAINDER OF TODAY INTO EARLY TONIGHT.
FOG/STRATUS DEVELOPMENT POSSIBLE AGAIN LATE TONIGHT/EARLY TUESDAY
MORNING.
EXTENDED AVIATION OUTLOOK MONDAY THROUGH THURSDAY...NO SIGNIFICANT
IMPACTS EXPECTED TUESDAY THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR SCZ027-028-
030-031-035>038-041.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
615 AM EDT MON APR 30 2012
.SYNOPSIS...
HIGH PRESSURE WILL PROVIDE FAIR WEATHER THROUGH THURSDAY. AN UPPER
LEVEL DISTURBANCE AND INCREASING ATMOSPHERIC MOISTURE MAY PROVIDE A
SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS FRIDAY AND SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
AREA OF STRATUS ENVELOPING THE COAST AND PEE DEE REGION EARLY
THIS MORNING. GFS/NAM AND RUC MODELS INDICATE LOW CLOUDS MOVING
WESTWARD INTO THE MIDLANDS THOUGH SUNRISE. WILL KEEP MENTION OF
PATCHY FOG IN THE FORECAST...BUT GIVEN LIGHT SOUTHEAST WIND FLOW
EXPECT MORE STRATUS THAN FOG. LOW CLOUDS/FOG IS EXPECTED TO CLEAR
AROUND MID-MORNING. UPPER LEVEL RIDGING WAS OVER THE REGION THIS
MORNING. SURFACE HIGH PRESSURE STRETCHED FROM EASTERN CANADA DOWN
THE EAST COAST TO THE GULF OF MEXICO. WARM AND DRY FORECAST
EXPECTED TODAY AND TONIGHT AS HIGH PRESSURES REMAINS IN CONTROL.
WENT SLIGHTLY ABOVE MOS GUIDANCE FOR AFTERNOON HIGHS...GIVEN ITS
COOL BIAS PAST FEW DAYS. TEMPERATURE WILL BE ABOVE NORMAL IN THE
MID 80S TO LOWER 90 THIS AFTERNOON. LOWS TONIGHT WILL BE
CONSISTENT IN THE LOW TO MID 60S. EXPECT LATE NIGHT/EARLY MORNING
LOW CLOUDS TO DEVELOP AGAIN TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
THE MID AND UPPER LEVEL RIDGE REMAIN OVER THE REGION THROUGH
THURSDAY NIGHT. THIS ALONG WITH A RELATIVELY DRY ATMOSPHERE WILL
SUPPRESS CONVECTION. THE CENTER OF SURFACE HIGH PRESSURE WILL
LINGER IN THE WESTERN ATLANTIC...YET CONTINUE TO CONTROL OUR
WEATHER. STILL EXPECT ABOVE NORMAL TEMPERATURES WITH AFTERNOON
HIGHS IN THE MID 80S TO LOWER 90S AND LOWS IN THE LOWER TO MIDDLE
60S.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
GFS/ECMWF INDICATE UPPER RIDGE NEAR THE SOUTHEAST COAST TO MOVE
EAST...WHILE UPPER ENERGY OVER FLORIDA SLOWLY SHIFTS
NORTH...JOINED BY OTHER IMPULSES SHIFTING EAST FROM THE EASTERN
PACIFIC...TO PROVIDE SOME TROUGHINESS AND POSSIBLY A CLOSED LOW
OVER THE DEEP SOUTH...MAINLY TO OUR WEST FOR THE END OF THE WEEK.
THIS ALONG WITH MOISTURE RETURN WILL BRING A CHANCE FOR
SHOWERS/THUNDERSTORMS MAINLY TO OUR WEST. ACCEPTED GUIDANCE
CONSENSUS OF SLIGHT CHANCE POPS FRI/SAT.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
VFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD...WITH MVFR/IFR
FOG/STRATUS OVER THE NEXT COUPLE OF HOURS. WEAK HIGH PRESSURE WILL
REMAIN OVER THE REGION TODAY WITH A FRONTAL BOUNDARY PASSING NORTH
OF THE AREA TONIGHT. STRATUS HAS MOVED INTO CAE/CUB/OGB FROM THE
EAST WITH CIGS BETWEEN 200 AND 700 FEET AND VSBYS UNDER 1 SM IN
THE OGB AREA. LOW CIGS WILL APPROACH AGS/DNL...HOWEVER WITH
SUNRISE AND MIXING WILL STRUGGLE TO REACH THE TAF SITES. WILL
REMAIN WITH TEMPO MVFR/IFR AT ALL SITES...EXCEPT DNL...OVER THE
NEXT COUPLE OF HOURS THEN CLEARING. REMAINDER OF TAF PERIOD WILL
BE VFR WITH WINDS UNDER 7 KNOTS.
EXTENDED AVIATION OUTLOOK MONDAY THROUGH THURSDAY...NO SIGNIFICANT
IMPACTS EXPECTED TUESDAY THROUGH FRIDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1114 AM EDT MON APR 30 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, COMING EAST FROM ILLINOIS, WILL BRING
SCATTERED SHOWERS AND THUNDERSTORMS TO PARTS OF THE UPPER OHIO
VALLEY THIS AFTERNOON WITH MORE NUMEROUS SHOWERS AND THUNDERSTORMS
TONIGHT INTO TUESDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER BLEND OF RECENT RADAR AND SURFACE DATA, PLUS RECENT HRRR AND
NAM MODEL OUTPUT, EXPECT A WARM FRONTAL BAND OF SCATTERED SHOWERS
AND THUNDERSTORMS TO PASS THROUGH WESTERN PENNSYLVANIA, MAINLY NORTH
OF PITTSBURGH THIS AFTERNOON. AS SURFACE DEW POINTS INCREASE, THE
COVERAGE OF SHOWERY PRECIPITATION CAN ALSO INCREASE.
HAVE ADJUSTED TEMPERATURES UP 1 OR 2 DEGREES FOR THE AFTERNOON,
PARTICULARLY SOUTH OF THE MAIN SHOWER BAND, ALTHOUGH HIGHS FOR
LOWER ELEVATIONS SOUTH CAN BE UP TO 15 DEGREES WARMER THAN
NORTHERN AND MOUNTAIN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
PER RECENT NAM MODEL OUTPUT, EXPECT COVERAGE OF SHOWERS AND
THUNDERSTORMS TO INCREASE TO NUMEROUS TONIGHT DUE TO INCREASED
CONVERGENCE AND LIFT ASSOCIATED WITH THE INCOMING EASTBOUND LOW
PRESSURE CENTER FROM ILLINOIS. WITH SURFACE MOISTURE ALSO
INCREASED, EXPECT INCREASED INSTABILITY.
SPC HAS OUTLOOKED MUCH OF THE AREA FOR A SLIGHT RISK OF SEVERE
THUNDERSTORMS WITH HAIL AND WIND THE TWIN THREAT.
MOST MEMBERS OF RECENT SREF MODEL OUTPUT, INCLUDING THE
OPERATIONAL NAM MODEL, SHOW THAT MOST POST-SYSTEM SHOWERS WILL
HAVE EXITED EAST PAST THE MOUNTAINS BY MIDDAY TUESDAY. HOWEVER, A
LINGERING FRONTAL BOUNDARY NEAR THE MASON-DIXON LINE MAY MAINTAIN
A CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORMS FOR THAT AREA INTO
THE AFTERNOON.
BY TUESDAY NIGHT, THAT FRONTAL BOUNDARY WILL BEGIN TO MOVE NORTHWARD
AGAIN AS DEEPENING SFC LOW OVER THE NORTHERN PLAINS INCREASES
SOUTHERLY WINDS ACROSS THE OHIO VALLEY.
UPPER LEVEL HEIGHTS WILL BEGIN TO RISE LATE TUESDAY NIGHT AND
WEDNESDAY MORNING. SO THE FRONT WILL MOVE THROUGH, BUT WITH
RIDGING ALOFT NOT QUITE SURE HOW MUCH SHOWER ACTIVITY WILL
DEVELOP. FOR NOW, THE BEST WAY TO HANDLE THIS WILL BE WITH LOW
CHANCE PRECIPITATION PROBABILITIES FOR WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
FOR THE EARLY PORTIONS OF THE LONG TERM FORECAST, MODELS ARE IN
DECENT AGREEMENT WITH THE OVERALL PATTERN. WARM FRONT WILL
PUSH TO THE NORTH LATE WED AND EARLY THU, ALLOWING THE AREA TO
ENTER BACK INTO THE WARM SECTOR ON THU. UL RIDGE WILL CONTINUE TO
BUILD IN THE EAST, SO AS TEMPS RISE THU, RAIN CHANCES WILL
DECREASE.
RIDGE STARTS TO BREAK DOWN FRIDAY ALLOWING SFC COLD FRONT TO MOVE
TOWARD THE AREA. THERE ARE TIMING DIFFERENCES IN THE MEDIUM RANGE
MODEL SOLUTIONS, SO STAYED CLOSE TO PREVIOUS FORECAST HERE.
IT DOES APPEAR THE FRONT WILL STALL OVER THE AREA THROUGH THE
WEEKEND WITH BIG QUESTIONS ON WHAT WILL HAPPEN WITH A SFC LOW
DEVELOPING OVER THE CENTRAL US. HAVE LOW CONFIDENCE WITH WEEKEND
FORECAST.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
A SHORT WAVE MOVING THROUGH THE UPPER RIDGE TODAY WILL BRING
GOOD WARM ADVECTION AND INCREASING LOW LEVEL MOISTURE.
SCATTERED SHOWERS AND THUNDERSTORMS CAN BE EXPECTED MAINLY
THIS AFTERNOON WITH THE HEATING OF THE DAY.
WEAK LOW PRESSURE ASSOCIATED WITH THE UPPER LEVEL SHORT
WAVE WILL PUSH INTO NORTHEAST OHIO BY EVENING BRINGING AN
INCREASING RISK OF SHOWERS AND ISOLATED THUNDERSTORMS. WILL
LEAVE MENTION OF THUNDER OUT OF THE TAFS DUE TO THE ISOLATED
NATURE OF THE STORMS...BUT THUNDER WILL BE MORE LIKELY AT
THE NORTHERN PORTS THAN IN THE SOUTH.
.OUTLOOK...TUESDAY THROUGH FRIDAY...
RESTRICTIONS IN SCT SHRA AND TSRA ARE POSSIBLE INTO WEDNESDAY AS
GREAT LAKES LOW PRESSURE ADVECTS WARMTH AND MOISTURE ACROSS THE
REGION. MORE TSRA ARE ANTICIPATED FOR THURSDAY AND FRIDAY IN
ASSOCIATION WITH THE SYSTEMS CDFNT APPROACH. FLIGHT CONDITIONS WILL
BE GENERALLY VFR THROUGH THE EXTENDED PERIOD WITH RESTRICTIONS
ONLY WITH SCATTERED STORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
648 AM CDT MON APR 30 2012
.UPDATE...
UPDATED TO INCLUIDE 12Z AVIATION DISCUSSION BELOW.
&&
.DISCUSSION...
IT APPEARS TO BE SHAPING UP TO BE A BUSY WEEK WEATHERWISE... WITH
CHANCES FOR PCPN SOMEWHERE OVER THE CWFA NEARLY EVERY DAY... AND
THE POTENTIAL FOR SEVERE WEATHER LATE TUESDAY AFTERNOON INTO
TUESDAY NIGHT. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR
ANALYSES SHOW THE PESKY UPPER LOW WHICH WAS OVER THE PLAINS THE
PAST SEVERAL DAYS HAS FINALLY LIFTED NORTHEAST INTO CENTRAL
CANADA. UPPER PV ANALYSIS SHOWS A FILAMENT EXTENDING SOUTH FROM
THIS INTO CENTRAL MINNESOTA AT THE CURRENT TIME... HELPING TO KEEP
A FEW SHRA GOING OVER THE NORTH CENTRAL PORTION OF THE STATE. A
SECOND PV FEATURE IS APPARENT NEAR THE SOUTHEAST MINNESOTA/WEST
CENTRAL WISCONSIN BORDER. THIS COMPACT ANOMALY IS ALSO LIFTING
NORTHEAST... HELPING TO TAKE ITS ASSOCIATED AREA OF SHRA ALONG
WITH IT. THE NEXT UPPER LEVEL FEATURE OF CONSEQUENCE IS A
SHORTWAVE APPARENT OFF THE PACIFIC NORTHWEST COAST. THIS SYSTEM
WILL WORK ACROSS THE NORTHWEST CONUS AND NORTHERN ROCKIES OVER THE
NEXT 24-36 HOURS... THEN PUSH INTO THE NORTHERN PLAINS TUESDAY
AFTERNOON AND EVENING... HELPING TO SET THE STAGE FOR
THUNDERSTORMS AND POSSIBLE SEVERE WEATHER OVER OUR AREA LATE
TUESDAY AFTERNOON AND TUESDAY NIGHT. THE UPPER RIDGE CURRENTLY IN
PLACE OVER THE SOUTHEAST CONUS LOOKS TO STUBBORNLY REMAIN IN PLACE
THROUGH THE WEEK... WHICH WILL HELP TO MAINTAIN SOUTHWEST UPPER
FLOW OVER THE NORTH CENTRAL US. THIS MEANS THE SYSTEM MOVING INTO
THE AREA TUESDAY NIGHT WILL HAVE A TOUGH TIME DISPLACING THE
BAROCLINIC ZONE SOUTHEAST OF OUR AREA... LEAVING AN UNSETTLED
SECOND HALF OF THE WEEK AS MOISTURE AND INSTABILITY LOITER NEARBY
AND A FEW ADDITIONAL SHORTWAVES RIPPLE NORTHEAST FROM THE CENTRAL
ROCKIES AND THROUGH THE NORTHERN PLAINS. THE MODELS ARE ACTUALLY
IN QUITE GOOD AGREEMENT ON THE OVERALL LARGE SCALE PATTERN THROUGH
THE WEEK. HOWEVER... THERE IS A FAIR DEGREE OF SPREAD IN THEIR
TIMING OF INDIVIDUAL SHORTWAVE FEATURES... THE EXACT POSITION OF
THE MAIN BAROCLINIC ZONE THROUGH THE WEEK... AND THE INTERPLAY OF
THESE FEATURES WITH CONVECTIVE DEVELOPMENT. STUCK CLOSE TO A BLEND
OF THE NAM AND GFS THROUGH TUESDAY... THEN HAD A TOUGH TIME
PUTTING MUCH FAITH IN THE SPECIFIC DETAILS OF ANY PARTICULAR
SOLUTION OR COMBINATION OF SOLUTIONS AFTER THAT POINT. THE MAIN
IDEA IS THAT AFTER TUESDAY WE WILL HAVE THE BAROCLINIC ZONE HANG
UP EITHER OVER THE SOUTHERN PORTION OF OUR AREA OR JUST TO THE
SOUTH... WHICH WILL BE CLOSE ENOUGH FOR PERIODIC PCPN CHANCES
THROUGH THE BALANCE OF THE WEEK AS SHORTWAVES OCCASIONALLY MIGRATE
THROUGH THE REGION WITH BOUNDARY LAYER BASED AND/OR ELEVATED
INSTABILITY REMAINING IN PLACE.
FOR TODAY... ABUNDANT LOW CLOUDS AND SOME PATCHY FOG WILL BE IN
PLACE TO START THE DAY... BUT WITH MID-HIGH CLOUDS PRIMARILY SOUTH
OF THE AREA INSOLATION SHOULD WORK TO ERODE THINGS THROUGH THE
MORNING HOURS. BY AFTERNOON WE SHOULD START TO SEE SOME BETTER
RETURN FLOW SETUP... WHICH SHOULD FURTHER ASSIST IN INCREASING
SUNSHINE ACROSS THE AREA. A SECONDARY PV ANOMALY ROTATING AROUND
THE UPPER LOW TO OUR NORTH... CURRENTLY SEEN OVER SOUTHERN
SASKATCHEWAN... WILL SLIDE BY TO OUR NORTH THIS AFTERNOON...
POSSIBLY BRINGING A FEW SHRA TO THE NORTH CENTRAL AND NORTHEAST
PORTION OF THE AREA. WOULDN/T BE SHOCKED IF A SHRA MADE IT AS FAR
SOUTH AS THE TWIN CITIES METRO LATER THIS AFTERNOON AS THIS
FEATURE MOVES BY TO OUR NORTH... BUT FOR NOW STUCK CLOSER TO THE
MODEL CONSENSUS OF KEEPING PCPN NORTH OF THAT AREA. RETURN FLOW
WILL INCREASE MARKEDLY OVER THE WESTERN HALF OF THE AREA
TONIGHT... WITH SUFFICIENT MOISTURE ADVECTION FOR PERHAPS SOME
SHRA/TSRA TO GET GOING OVERNIGHT ACROSS WEST CENTRAL MINNESOTA.
THE BEST FOCUS OF MOISTURE AND FORCING ALONG THE ELEVATED WARM
FRONTAL BOUNDARY LOOKS TO BE NORTH OF OUR AREA LATE TONIGHT INTO
TUESDAY MORNING... BUT SOME ACTIVITY COULD CERTAINLY EXTEND BACK
INTO WEST CENTRAL AND CENTRAL MINNESOTA.
TUESDAY WILL BRING EVEN WARMER TEMPERATURES INTO THE AREA AS WE
FIND OURSELVES IN THE WARM SECTOR AHEAD OF A FRONTAL BOUNDARY
EXTENDING FROM LOW PRESSURE IN SOUTHWEST MANITOBA BACK INTO
CENTRAL NEBRASKA. EXPECT TO SEE SHRA/TSRA DEVELOP JUST WEST OF OUR
AREA TUESDAY AFTERNOON... WITH PERHAPS SOME ADDITIONAL STORMS
DEVELOPING OVER OUR AREA OUT AHEAD OF WHAT SHOULD EVENTUALLY
EVOLVE INTO A BROKEN LINE OF STORMS MOVING FROM THE EASTERN
DAKOTAS INTO WESTERN MINNESOTA DURING THE LATE AFTERNOON AND EARLY
EVENING. THE BEST UPPER FORCING ASSOCIATED WITH THE SHORTWAVE
CURRENTLY OFF THE PACIFIC NORTHWEST COAST WON/T WORK INTO THE AREA
UNTIL LATER TUESDAY EVENING AND INTO THE OVERNIGHT HOURS.
HOWEVER... THERE APPEARS TO BE MORE THAN SUFFICIENT LOW LEVEL
CONVERGENCE AND FRONTOGENETICAL FORCING TO GET STORMS GOING IN AN
ENVIRONMENT WHICH SHOULD SEE MLCAPE VALUES AOA 1500 J/KG AND 0-6KM
BULK SHEAR AOA 40KT. WHEN THE BETTER LARGE SCALE FORCING WORKS
INTO THE REGION LATER IN THE EVENING AND DURING THE OVERNIGHT...
IT WILL LIKELY SERVE TO KEEP THE ACTIVITY GOING AS IT MOVES ACROSS
THE REMAINDER OF MINNESOTA AND INTO WESTERN WISCONSIN. AS THINGS
MIGRATE EAST DURING THE EVENING WOULD EXPECT TO SEE ACTIVITY
EVOLVE INTO A LINEAR SYSTEM... WITH PERHAPS SOME EMBEDDED BOWS
GIVEN 0-2KM BULK SHEAR AOA 25KT ORIENTED PERPENDICULAR TO AN
ANTICIPATED NORTH-SOUTH LINEAR SYSTEM. PRIMARY SEVERE THREATS
SHOULD BE DAMAGING WINDS AND LARGE HAIL FROM LATE TUESDAY
AFTERNOON THROUGH AT LEAST 06Z THAT NIGHT... ALTHOUGH A FEW
TORNADOES CANNOT BE RULED OUT WITH DISCRETE SUPERCELLS WHICH MAY
OCCUR EARLY-ON AS WELL AS EMBEDDED SUPERCELL
STRUCTURES/MESOVORTICES WITH A POTENTIAL LINEAR SYSTEM LATER IN
THE EVENING. THERE REMAINS A FAIR DEGREE OF SPREAD IN THE MODEL
DETAILS WITH RESPECT TO SHEAR PROFILES... PARTICULARLY SUB-2KM
SHEAR BOTH IN TERMS OF SPEED AND DIRECTIONAL COMPONENTS. NEEDLESS
TO SAY... THINGS WILL NEED TO BE MONITORED OVER THE NEXT 24 HOURS
AS THINGS COME INTO BETTER FOCUS AND ADDITIONAL INFORMATION
BECOMES AVAILABLE FROM CONVECTION ALLOWING MODELS. AT THIS
POINT... THE INITIAL CONVECTIVE DEVELOPMENT NEAR THE
DAKOTAS/MINNESOTA BORDER IS OCCURRING RIGHT AT THE END OF THE HIGH
RESOLUTION WINDOW RUNS... ALTHOUGH IT SHOULD BE NOTED THAT BOTH
THE NMM AND ARW SHOW A FEW INDIVIDUAL STORMS QUICKLY ACQUIRING
UPDRAFT HELICITY VALUES AOA 40 M2/S2 BETWEEN 22Z AND 00Z. IN
ADDITION... THE 03Z SREF TORNADO INGREDIENT PROBABILITIES
HIGHLIGHT AN AREA NEAR AND WEST OF THE I-35 CORRIDOR AROUND
00-03Z... SUGGESTING THERE MAY BE A WINDOW OF TIME WHEN CONDITIONS
WILL BE FAVORABLE FOR TORNADIC STORMS.
THE REMAINDER OF THE FORECAST IS QUITE MUDDY... FIGURATIVELY AND
PERHAPS LITERALLY... AFTER TUESDAY NIGHT/S SYSTEM MOVES THROUGH
THE AREA. WITH THE UPPER RIDGE REMAINING IN PLACE IN THE SOUTHEAST
CONUS... HEIGHTS FALL LITTLE ACROSS THE NORTH CENTRAL PART OF THE
COUNTRY... AND THEREFORE THE FRONTAL BOUNDARY WHICH PUSHES INTO
THE AREA TUESDAY NIGHT WILL LINGER NEARBY FOR SEVERAL DAYS.
SHOWERS AND THUNDERSTORM CHANCES LOOK GOOD FROM WEDNESDAY INTO THE
WEEKEND. THE SOUTHERN PORTION OF THE AREA... CLOSER TO THE OLD
FRONTAL BOUNDARY... COULD SEE A SIGNIFICANT AMOUNT OF PCPN OVER
THAT PERIOD OF TIME DEPENDING UPON HOW INDIVIDUAL SHORTWAVES MOVE
THROUGH THE REGION AND WHERE CONVECTION SETS UP AND TRACKS. IT
WILL DEFINITELY NOT BE RAINING THE ENTIRE TIME PERIOD... BUT EACH
DAY LOOKS TO HAVE SOME CHANCE FOR SHRA/TSRA. HOPEFULLY THE
FORECAST CAN BE REFINED TO BETTER IDENTIFY DRY/WET PERIODS AS THE
WEEK PROGRESSES.
&&
.AVIATION.../12Z TAF ISSUANCE/
LOW CLOUDS/FOG PLAGUING ALL TAF SITES EARLY THIS MORNING UNDER
PASSING HIGH PRESSURE...LIGHT SOUTHERLY FLOW AND INCREASING LOW
LEVEL MOISTURE. AFTER DAYBREAK...THE LOW LEVEL MOISTURE TRAPPED
UNDER THE INVERSION WILL BE SCOURED OUT IN LATE-MORNING MIXING...
ALLOWING FOR FAIRLY STEADY CONVERSION TO VFR. SCATTERED MID- AND
HIGH- CLOUDS WILL THEN PREVAIL THROUGH THE DAY WITH AN INCREASE IN
COVERAGE TONIGHT THROUGH TUESDAY MORNING AHEAD OF THE NEXT WEATHER
SYSTEM. ASIDE FROM POSSIBLY FROM PATCHY -DZ WITHIN THE FOG...NO
PRECIP IS EXPECTED THROUGH THIS EVENING AT ANY SITE. AFTER
MIDNIGHT...IF THE PRECIP MOVES IN QUICKER THAN EXPECTED...KAXN AND
KSTC COULD SEE A FEW SHOWERS BEFORE DAWN TUESDAY MORNING BUT
KEEPING IN LINE WITH THE REST OF THE FCST...HAVE KEPT THINGS DRY.
WINDS WILL BECOME SOUTHWEST AT ALL SITES BY LATE MRNG AND INCREASE
TO ARND 10 KT BEFORE SETTLING DOWN THIS EVENING.
MSP...IFR CONDITIONS TO START WITH A TRANSITION TO MVFR CIGS
THROUGH LATE MRNG BEFORE GETTING TO VFR BY NOON. AM EXPECTING CIGS
TO LIFT ABOVE 1700 FT BY 15Z...IF NOT ABOUT AN HOUR SOONER...WITH
WINDS ALSO GOING SW AT ABOUT THE SAME TIME. VFR CONDITIONS THEN
PREVAIL THROUGH THE REST OF THE TAF PERIOD...ALBEIT WITH
DECREASING CLOUDS TODAY FOLLOWED BY INCREASING CLOUDS TONIGHT. NO
PRECIP EXPECTED THROUGHOUT THIS TAF PERIOD...ALTHOUGH LATER TAFS
MAY WELL NEED TO MAKE SOME PRECIPITATION INTRODUCTIONS.
OUTLOOK...
TUESDAY NIGHT...MVFR-IFR WITH TSRA LIKELY...INCLUDING WINDS S AT
20KTS WITH HIGHER GUSTS.
WEDNESDAY...VFR/MVFR WITH -TSRA POSSIBLE.
THURSDAY...VFR/MVFR WITH -TSRA POSSIBLE.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPC
AREA FORECAST DISCUSSION
NWS HASTINGS NE
611 AM CDT MON APR 30 2012
.UPDATE...SENT AN UPDATE TO THE FORECAST TO CANCEL THE DENSE FOG
ADVISORY AS A BAND OF LIGHT SHOWERS AND SPRINKLES HAS HELPED TO
CLEAR OUT THE WIDESPREAD DENSE FOG WE SAW EARLY THIS MORNING. EVEN
SO...EXPECT SOME FOG TO REDEVELOP OVER THE NEXT FEW HOURS...WHICH
MAY BRIEFLY REDUCE VISIBILITIES BELOW ONE MILE. OTHERWISE...ALSO
TONED DOWN POPS FOR THE REMAINDER OF THE DAY...AS WITH LOW STRATUS
AROUND THIS MORNING...DO NOT THINK INSTABILITY WILL EXIST TO HELP
PROMOTE ANY SHOWER OR THUNDERSTORM ACTIVITY THROUGH AT LEAST
NOON...WITH A LIMITED CHANCE FOR THUNDERSTORMS THIS AFTERNOON AND
EVENING...PRIMARILY ACROSS NORTH CENTRAL KANSAS WHICH WILL BE
CLOSER TO THE VICINITY OF THE WARM FRONT TO OUR SOUTH. NO OTHER
CHANGES MADE TO CURRENT FORECAST.
&&
.PREV DISCUSSION... /ISSUED 432 AM CDT MON APR 30 2012/
SHORT TERM...THROUGH 12Z THURSDAY...LATEST SATELLITE IMAGERY THIS
MORNING INDICATING WIDESPREAD STRATUS ACROSS THE LOCAL AREA.
UNDERNEATH THIS STRATUS...WITH LIGHT WINDS AND ELEVATED
DEWPOINTS...SAW SOME VERY DENSE FOG FORM IN SPOTS ACROSS THE
REGION THE PAST FEW HOURS...WITH THE MOST DENSE AREAS AFFECTING
THE TRI CITIES REGION. WHILE VISIBILITIES WILL IMPROVE SOME
THROUGH THE EARLY MORNING HOURS AS WINDS BEGIN TO INCREASE AND THE
BOUNDARY LAYER ELEVATES...COULD NOT IGNORE NUMEROUS OBSERVATIONS
WITH VISIBILITIES OF 1/4 SM OR LESS...AND WENT AHEAD AND ISSUED A
DENSE FOG ADVISORY THROUGH 10 AM CDT FOR PORTIONS OF SOUTH CENTRAL
NEBRASKA. TO THE EXTREME WEST...ACROSS FURNAS AND GOSPER
COUNTIES...HAVE SEEN A FEW LIGHT SHOWERS SPREAD EASTWARD...AND
SUSPECT CONDITIONS ACROSS THIS AREA HAVE IMPROVED SOME...AS SEEN
IN MCK...SO KEPT THIS AREA OUT OF ADVISORY.
EXPECT THE FEW LIGHT SHOWERS ACROSS WESTERN PORTIONS OF THE
FORECAST AREA THIS MORNING TO SLOWLY DISSIPATE AS THEY ATTEMPT TO
TRACK FURTHER EASTWARD...AS VIRTUALLY NO INSTABILITY OR FORCING
IS EVIDENT TO KEEP THEM GOING. EVEN SO...LATEST MODES ARE TRYING
TO FIRE UP QUITE A BIT OF SHOWER ACTIVITY ACROSS THIS AREA THROUGH
THE AFTERNOON HOURS...BUT GIVEN THEIR HANDLING OF CURRENT
SITUATION...HAVE DISCOUNTED MUCH...IF ANY...FURTHER DEVELOPMENT.
DID MAINTAIN SOME SMALL POPS AS WE GO THROUGH THE DAY ANYHOW...BUT
THINK BULK OF SHOWER ACTIVITY WILL BE WELL TO OUR SOUTH ALONG WARM
FRONTAL BOUNDARY.
AS WE HEAD INTO THE EVENING HOURS TONIGHT...PROGRESSIVE UPPER FLOW
PATTERN WILL CONTINUE ACROSS THE REGION...WITH FOCUS OF NEXT SHORT
WAVE AIMED WELL TO THE SOUTH. ONCE AGAIN...HOWEVER...WITH LIGHT
SOUTHEASTERLY WINDS AND GOOD LOW LEVEL MOISTURE...EXPECT AT LEAST
THE POSSIBILITY FOR SOME PATCHY FOG FORMATION...AND WENT AHEAD AND
INSERTED A MENTION INTO FORECAST FOR TUESDAY MORNING.
THEREAFTER...IT APPEARS THE MAIN FOCUS WILL SHIFT TO THE LATE
AFTERNOON THROUGH EVENING HOURS TUESDAY...WHEN A FRONTAL BOUNDARY
IS FORECAST TO SWEEP SOUTHEASTWARD ACROSS THE LOCAL AREA. WITH
VERY MOIST AIR AHEAD OF THIS BOUNDARY AND MU CAPE VALUES OF
2-3KJ...COULD SEE SOME STRONG OR EVEN SEVERE STORMS DEVELOP ACROSS
THE LOCAL AREA...AND WILL HIGHLIGHT THIS IN HWO.
FOR THE REMAINDER OF THE SHORT TERM...EXPECT YET ANOTHER
BOUNDARY...COUPLED WITH SOME UPPER SHORTWAVE ENERGY...TO TRACK
ACROSS THE LOCAL AREA LATE WEDNESDAY THROUGH THURSDAY
MORNING...IN A CONTINUED PROGRESSIVE WEST SOUTHWESTERLY FLOW. MAIN
AXIS OF INSTABILITY APPEARS FOCUSED JUST EAST OF THE LOCAL AREA
WEDNESDAY AFTERNOON/EVENING...BUT STILL EXPECT ENOUGH INSTABILITY
TO SUPPORT THE DEVELOPMENT OF POTENTIALLY STRONG STORMS ACROSS
THE LOCAL AREA.
LONG TERM...12Z THURSDAY THROUGH SUNDAY. MAIN FORECAST CONCERNS
WILL BE CHANCES FOR THUNDERSTORMS AND TEMPERATURES.
CONTINUES TO HAVE SEVERAL FAST MOVING SYSTEMS THAT MOVE THROUGH THE
FORECAST AREA DURING THE PERIOD. THE MAIN CONCERN WITH THIS IS
TIMING THE WEAK SYSTEMS AS THEY MOVE THROUGH AND THE MODELS HAVE A
HARD TIME CAPTURING THESE. THERE ARE SMALL CHANCES FOR THUNDERSTORMS
JUST ABOUT ANY PERIOD SOMEWHERE. THE BEST CHANCES WILL BE THURSDAY
AND THURSDAY NIGHT AS A SURFACE LOW AND BOUNDARY MOVE THROUGH THE
FORECAST AREA. FRIDAY AND FRIDAY NIGHT APPEAR DRY WITHOUT MUCH OF A
WAVE MOVING THROUGH AND WEAK SURFACE HIGH PRESSURE.
A STRONGER WAVE AND SURFACE LOW AND BOUNDARY ARE EXPECTED SATURDAY
THROUGH SUNDAY. THIS WILL BE THE BEST CHANCE FOR THUNDERSTORMS
DURING THE PERIOD.
PREV DISCUSSION... /ISSUED 1227 AM CDT MON APR 30 2012/
AVIATION...06Z KGRI TAF...DETERIORATING CONDS EXPECTED AT KGRI
DURING THE OVERNIGHT HOURS AS DEVELOPING LOW LEVEL STRATUS AND FOG
ARE OVERTAKING THE TERMINAL. LATEST SATELLITE IMAGERY SHOWS STRATUS
BEGINNING TO FILL IN ACROSS MUCH OF SOUTH CENTRAL NEBRASKA...AND
LIFR CIGS AND VSBYS BEGINNING TO BE REPORTED AT SEVERAL SITES.
ONCE THE STRATUS AND FOG SETTLES IN...DO NOT EXPECT MUCH IN THE
WAY OF IMPROVEMENT THROUGH THE REMAINDER OF THE OVERNIGHT
HOURS...AS LIGHT EASTERLY WINDS AND A SATURATED BOUNDARY LAYER AND
STRONG INVERSION WILL HELP MAINTAIN LIFR CONDS THROUGH AROUND
30/14Z. LATEST HRRR INDICATES STRATUS AND FOG WILL LIKELY BEGIN TO
DISSIPATE AROUND THIS TIME...WITH A RETURN TO VFR CIGS AND
VISIBILITIES BY ABOUT 30/16Z. STUCK VERY CLOSE TO THIS
GUIDANCE...AS IT SEEMS TO HAVE A PRETTY GOOD HANDLE ON DEVELOPING
CONDS EARLY THIS MORNING. CANNOT RULE OUT A STRAY SHRA OR TSRA AT
THE TERMINAL LATE TOMORROW AFTERNOON OR EARLY EVENING...BUT DID
NOT MENTION IN CURRENT TAF AS CONFIDENCE IS FAIRLY LOW FOR
SIGNIFICANT COVERAGE. ONCE AGAIN...LATEST GUIDANCE INDICATING A
RETURN TO SOME LLVL STRATUS AND FOG FORMATION TOMORROW NIGHT IN
SOUTHERLY WIND FLOW...BUT WINDS APPEAR MORE ELEVATE...WITH SHOULD
KEEP ANY REDUCED CIGS AND VSBYS JUST BEYOND CURRENT VALID PERIOD
OF TAF.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...ROSSI
LONG TERM...JCB
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
934 AM EDT MON APR 30 2012
.SYNOPSIS...
AFTER A VERY COLD START...A WARM SOUTHWEST FLOW WILL BRING WARMER
TEMPERATURES TO THE REGION TODAY. MOISTURE WILL ARRIVE AHEAD OF A
FRONTAL SYSTEM THIS EVENING...WITH SCATTERED SHOWERS AND A FEW
THUNDERSTORMS EXPECTED OVERNIGHT. THE FRONT WILL MOVE THROUGH
EARLY TUESDAY...ALLOWING SHOWERS TO CLEAR OUT BY LATE MORNING...YET
CLOUDS MAY LINGER INTO TUESDAY AFTERNOON. A WARM AND UNSETTLED
PATTERN IS EXPECTED WEDNESDAY THROUGH FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...FORECAST ON TRACK WITH LITTLE TO CHANGE. A QUICK
CHECK OF THE LATEST RUC SOUNDINGS SHOWS THAT WE SHOULD BE ABLE TO
MIX DOWN SOME VERY DRY AIR LATER THIS MORNING INTO THIS AFTERNOON.
LOWERED DEWPOINTS INTO THE TEENS TO LOWER 20S ESPECIALLY IN NEPA
TO ACCOUNT FOR THIS. DESPITE THIS DRY AIR...RELATIVELY LIGHT WINDS
WILL MINIMIZE FIRE WEATHER CONCERNS. THE PREVIOUS AFD IS BELOW...
A WIDESPREAD HARD FREEZE IS OBSERVED THIS MORNING. MANY LOCATIONS
HAVE FALLEN INTO THE LOWER AND MIDDLE 20S, ESPECIALLY IN THE
CENTRAL SOUTHERN TIER VALLEYS AND THE CATSKILLS/EASTERN
SUSQUEHANNA REGION.
MINOR CHANGES THIS MORNING TO REFLECT TEMPERATURE AND DEW POINT
TRENDS. THE MAIN FORECAST IS ON COURSE.
PREVIOUS DISCUSSION...
STRONGLY DECOUPLED LOWER ATMOSPHERE WILL BRING A VERY COLD
MORNING. BUT MUCH WARMER AIR ALOFT WILL WORK ITS WAY DOWN TO THE
SURFACE DURING MID MORNING MIXING HOURS.
MAIN CHANGE WE MADE TO THE NEAR TERM THIS PACKAGE WAS TO SCALE
BACK THE CLOUDS THROUGH MID AFTERNOON. SOUNDINGS LOOK EXTREMELY
DRY, AND THERE IS LITTLE UPSTREAM SAVE FOR THIN CIRRUS. CLOUDS
WILL MOVE IN RAPIDLY DURING THE LATE AFTERNOON, BUT THE MAJORITY
OF THE DAY SHOULD BE MOSTLY SUNNY WITH TEMPS IN THE LOWER 60S.
PRECIP SHOULD ARRIVE NEAR SUNSET IN THE WESTERN FA, THEN SPREAD
EASTWARD OVER THE FOLLOWING 3 HOURS. INSTABILITY ALOFT SUGGESTS
THUNDER POTENTIAL, AND WE HAVE INCREASED THE AREAL AND TEMPORAL
COVERAGE FOR CHC THUNDER. NAM DEPICTS LARGE AREA OF 33+ K-INDICES
FOR A 3-6 HOUR WINDOW LATE TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
EMBEDDED WAVE ALOFT FINISHES MOVING THROUGH EARLY
TUESDAY...HELPING SHALLOW SURFACE FRONT TO SETTLE THROUGH MOST OR
ALL OF THE AREA. MOST SHOWER ACTIVITY WILL EXIT WITH THE UPPER
WAVE...BUT SHALLOW MOISTURE WILL BE LEFT HANGING UNDERNEATH
INVERSION WHILE WARM AIR ADVECTION STRENGTHENS ALOFT. THIS WILL
LET CLOUDS LINGER LONGER THAN THE SHOWERS...INTO TUESDAY
AFTERNOON...THOUGH WITH GRADUAL EROSION INTO TUESDAY NIGHT AS
SURFACE FRONT REVERSES DIRECTION AND HEADS NORTH AS A WARM FRONT.
NEAR NORMAL TEMPERATURES TUESDAY...UPON PASSAGE OF THE WARM FRONT
AND CONTINUED HEIGHT RISES FROM BUILDING UPPER RIDGE...WILL TREND
TO 14-18 DEGREES ABOVE NORMAL WEDNESDAY THROUGH FRIDAY.
HOWEVER...OUR REGION APPEARS LIKELY TO STILL BE EMBEDDED WITHIN
SOUTHERN PERIPHERY OF THE WESTERLIES...WITH MULTIPLE WAVES PASSING
THROUGH DURING THE PERIOD. MODELS ARE CONVERGING ON HAVING ONE OF
THESE WAVES PASS THROUGH WITH POTENTIAL FOR NOCTURNAL CONVECTION
WEDNESDAY NIGHT...SO I INCREASED POPS TO AROUND 50 PCT...WITH LESS
CERTAINTY IN DETAILS YET STILL CHANCE POPS FOR THU-FRI.
WHILE SHEAR IS NOT ALL THAT GREAT DURING THE PERIOD...DECENT CAPES
AND GENERAL PATTERN RECOGNITION WOULD SUGGEST THAT WE WILL HAVE TO
MONITOR POTENTIAL FOR SOME STRONG THUNDERSTORMS LATE WED THROUGH
FRI. MODELS DISAGREE FRIDAY ON TIMING OF COLD FRONT...BUT IF IT
OCCURS LATER IN THE DAY...IT WOULD BE MORE DIURNALLY FAVORABLE FOR
STRONGER CONVECTION.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
GFS AND ECMWF DISAGREE ON HOW MUCH RIDGE GETS BEATEN DOWN OVER THE
WEEKEND...IN WAKE OF FRONT FROM FRIDAY. ECMWF GENERALLY STALLS
FRONT IN OUR VICINITY SATURDAY AND THEN SENDS ANOTHER SYSTEM
THROUGH SUNDAY...WHILE GFS MORE THOROUGHLY FLATTENS THE RIDGE AND
SHIFTS FRONTAL ZONE SOUTH TO THE MIDATLANTIC REGION...WITH NO
SYSTEM PASSING THROUGH SUNDAY. GIVEN LARGE SCALE UNCERTAINTIES...I
HELD THE LINE AT ONLY SLIGHT TO LOW CHANCE POPS. I ALSO TRENDED
TEMPERATURES BACK CLOSER TO CLIMATOLOGICAL NORMS...SINCE RIDGE
WILL AT LEAST BE BEATEN DOWN SOME...IF NOT COMPLETELY FLATTENED.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
WILL BE ADDING SOME GUSTS OF 14 TO 18 KNOTS TO THE TERMINALS THIS
AFTERNOON, BASED ON LATEST MODEL INDICATIONS FOR MOMENTUM
TRANSFER.
VFR CONDITIONS ARE FORECAST FOR THE FIRST 24 HOURS. SKIES WILL BE
MAINLY CLEAR AND WINDS WILL BE LIGHT, WITH SATELLITE OBSERVATION
SUGGESTING THICKENING CLOUDS WILL HOLD OFF UNTIL LATE AFTERNOON.
SHOWERS WILL ARRIVE THIS EVENING, AND THERE IS A CHANCE FOR
THUNDERSTORMS FOR ALL THE TERMINALS DURING THE OVERNIGHT HOURS DUE
TO INSTABILITY ALOFT. THUNDER ACTIVITY SHOULD BE VERY WIDELY
SCATTERED, AND FORECAST COVERAGE DOES NOT JUSTIFY A TEMPO GROUP AT
THIS TIME.
.OUTLOOK...
TUE / WED...VFR.
LATE WED AFTERNOON THRU FRI...MVFR RESTRICTION POSSIBLE IN SHRA/TSRA
ACTIVITY.
&&
.FIRE WEATHER...
ANOTHER VERY DRY DAY IS FORECAST WITH MIN RH VALUES IN THE 20-25
PERCENT RANGE DURING THE AFTERNOON HOURS. HOWEVER WINDS WILL BE
MUCH LIGHTER THIS PERIOD, SO WE DO NOT EXPECT ANY FLAGS WILL BE
NEEDED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJP/MDP
NEAR TERM...DJP/HEDEN
SHORT TERM...MDP
LONG TERM...MDP/TAC
AVIATION...DJP
FIRE WEATHER...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1033 AM EDT MON APR 30 2012
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH ACROSS THE AREA TODAY. AN UPPER LEVEL
WEATHER DISTURBANCE WILL COMBINE WITH A WEAK COLD FRONT TONIGHT TO
PRODUCE SHOWERS AND THUNDERSTORMS. EMBEDDED DISTURBANCES ALOFT
WILL CONTINUE TO RIPPLE ACROSS THE REGION THROUGH MID
WEEK...KEEPING THE THREAT OF SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE USED A BLEND OF THE GFS/ECMWF AS THE NAM-WRF HAS TOO MANY
NEGATIVE FEEDBACK ISSUES DUE TO CONVECTION.
SOUTHWESTERLY FLOW ALOFT IS UNDERWAY THIS MORNING. THIS PATTERN
WILL LIFT A WARM FRONT NORTHWARD ACROSS THE REGION THROUGH EARLY
AFTN. A MUCH WARMER AND MORE HUMID AIRMASS CAN BE EXPECTED IN THE
WAKE OF THIS FRONT...MORE LIKE LATE JUNE WEATHER THAN THE END OF
APRIL. A FEW SHOWERS AND THUNDERSTORMS MAY OCCUR AS THE WARM FRONT
PASSES BY. THEN...EYES TURN TOWARD THE WEST AS A WEAK AREA OF LOW
PRESSURE IS FORECAST TO TRAVERSE ACROSS NRN INDIANA INTO NW OHIO
LATE IN THE DAY. A WEAK COLD FRONT WILL BEGIN TO SAG TOWARD THE NW
CWFA THIS AFTERNOON...INCREASING THE THREAT OF SHOWERS AND STORMS
THERE. FOR THE REMAINDER OF THE AREA...THE MAIN PCPN THREAT IS
EXPECTED THIS EVENING AND OVERNIGHT AND IS DISCUSSED IN THE
SHORT TERM SECTION. CLOUDS AND PCPN WILL KEEP TEMPERATURES COOLER
ACROSS THE NW. HIGHS WILL RANGE FROM THE MID 70S FAR NORTHWEST TO
THE MID 80S SOUTHEAST.
RAISED HIGHS A COUPLE DEGREES IN NORTHWEST COUNTIES DUE TO RAPID
INCREASE IN TEMPERATURES EARLY TODAY. ALSO DELAYED ONSET OF
THUNDERSTORMS CHANCE BY A FEW HOURS BASED ON LACK OF RADAR
ECHOES...AND DECREASED SKY COVER BECAUSE OF SATELLITE TRENDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AN EMBEDDED S/WV IS FORECAST TO MOVE ACRS THE REGION OVERNIGHT. IT
IS UNCLEAR IF CONVECTION WILL GET GOING NEAR THE WEAK COLD FRONT
TO OUR NW LATE IN THE DAY...THEN PROPAGATE ESE TOWARD THE BETTER
AXIS OF INSTABILITY OR PERHAPS DEVELOP NEAR A SUBTLE WEAK
PREFRONTAL TROF AS THE LATEST HRRR SUGGESTS. IN EITHER
CASE...CONVECTION SHOULD INCREASE THIS EVENING AS THE S/WV ALOFT
INTERACTS WITH MODERATE INSTABILITY. MODELS SUGGEST THAT THE S/WV
WILL BE ASSOCIATED WITH A 50 TO 60 KNOT MID LVL JET. THE
COMBINATION OF SHEAR AND INSTABILITY SHOULD RESULT IN MUTICELLULAR
CLUSTERS THAT MAY MERGE INTO LINES AND/OR BOWING SEGMENTS. A
SUPERCELL CAN NOT BE RULED OUT EITHER. THE THREAT FOR SOME SEVERE
STORMS WILL BE THERE WITH DAMAGING WIND AND LARGE HAIL BEING THE
PRIMARY SEVERE WEATHER THREATS. WILL EMPHASIZE THIS THREAT IN THE
HWO. STORMS SHOULD HAVE ENOUGH MOVEMENT TO PREVENT A SIGNIFICANT
FLOOD THREAT...BUT WITH PWATS INCREASING TO 1.50 INCHES...HEAVY
RAIN AND LOCALIZED FLOODING ARE A POSSIBILITY. GIVEN STATED
PARAMETERS ABOVE...HAVE CONTINUED WITH LIKELY POPS TONIGHT AS
CONVECTION SHOULD MOVE ESE THROUGH THE OVERNIGHT HOURS. OVERNIGHT
LOWS WILL RANGE FROM THE UPPER 50S TO THE LOWER 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE WEAK COLD FRONT IS FORECAST TO STALL NEAR THE NRN CWFA BY
TUESDAY MORNING. IN A WARM AND UNSTABLE AIRMASS...WILL CONTINUE
WITH CHANCE POPS ON TUESDAY. A BETTER CHANCE OF SHOWERS AND STORMS
MAY OCCUR LATE TUESDAY AFTERNOON AND OVERNIGHT AS ANOTHER EMBEDDED
DISTURBANCE RIPPLES BY ALOFT. THERE APPEARS TO BE LESS SHEAR AND
LOW LEVEL FOCUS WITH THIS ROUND OF PCPN AS WELL AS WEAKER
INSTABILITY SO THE SEVERE THREAT WILL BE MARGINAL. GIVEN
APPRECIABLE PWATS...THE THREAT OF LOCALIZED FLOODING WILL
CONTINUE. HIGHS ON TUESDAY WILL BE A LITTLE COOLER GIVEN CLOUDS
AND SHOULD RANGE FROM THE MID TO UPPER 70S. LOWS TUESDAY NIGHT
WILL FALL INTO THE LOWER 60S.
DEEPER MOISTURE WILL PIVOT NE ON WEDNESDAY AS S/WV MOVES OFF TO
THE EAST. THIS SHOULD ALLOW FOR A DECREASING THREAT OF SHOWERS AND
THUNDERSTORMS FROM WEST TO EAST THROUGH THE DAY. WARM TEMPERATURES
WILL OCCUR WITH HIGHS IN THE LOWER TO MID 80S.
FOR WEDNESDAY NIGHT INTO THURSDAY...MODELS TRY TO BUILD A MID LVL
RIDGE FROM THE SE U.S. NORTH AND WESTWARD INTO THE OHIO VALLEY.
THIS SHOULD GIVE THE REGION A DRY PERIOD ALONG WITH PERHAPS THE
WARMEST TEMPERATURES OF THE WEEK WITH MOST LOCATIONS REACHING INTO
THE MID 80S.
SEVERAL DISTURBANCES ALOFT ARE FORECAST TO RIDE UP THE BACK SIDE
OF THE MID LVL RIDGE THURSDAY NIGHT INTO FRIDAY AND THIS WILL
EVENTUALLY HELP FLATTEN OUT THE RIDGE. THIS WILL ALSO ALLOW FOR A
COLD FRONT TO SAG DOWN FROM THE NORTH AND POSSIBLY LAY OUT ACROSS
OUR AREA FRIDAY INTO SATURDAY. AS THE RIDGE BEGINS TO BREAK
DOWN...WILL ALLOW FOR A CHANCE OF SHOWERS AND THUNDERSTORMS TO
PUSH DOWN INTO OUR AREA THURSDAY NIGHT INTO FRIDAY. HOW LONG THE
PCPN THREAT LINGERS WILL DEPEND ON EXACTLY HOW FAR SOUTH THE
BOUNDARY IS ABLE TO PUSH. FOR NOW WILL SLOWLY TAPER POPS OFF FROM
THE NORTH HEADING INTO SATURDAY. TEMPERATURES WILL ALSO BE
DEPENDENT ON THE PLACEMENT AND TIMING OF THE BOUNDARY. WILL
SLOWLY DECREASE TEMPERATURES THROUGH THE REMAINDER OF THE
EXTENDED PERIOD AS THE UPPER LEVEL RIDGE BEGINS TO WEAKEN AND THE
POSSIBILITY OF SOME PCPN DEVELOPS.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
A WARM FRONT IS CURRENTLY PUSHING NORTH OF THE TAF SITES...WHICH
SHOULD END PRECIPITATION CHANCES FOR THE MORNING. SHOWERS NEAR
COLUMBUS WILL HAVE MOVED AWAY...LEAVING THE CWA IN THE BUILDING
WARM SECTOR FOR THE FIRST HALF OF THE DAY. WINDS WILL GRADUALLY
SHIFT TO THE SOUTHWEST...WITH GUSTS OF UP TO 20 KNOTS EXPECTED
THROUGH THE AFTERNOON HOURS.
THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BEGIN TO INCREASE
BY LATE AFTERNOON...WITH THE BEST CHANCES COMING DURING THE
EVENING HOURS. THERE IS HIGH CONFIDENCE IN PRECIPITATION AFFECTING
THE TAF SITES...WITH THUNDER EXPECTED AS WELL. EXACT TIMING IS NOT
CERTAIN RIGHT NOW...BUT THERE WILL LIKELY BE PERIODS OF REDUCED
AVIATION CONDITIONS...AND POSSIBLY STRONG STORMS AS WELL.
FOR THE NORTHERN TAF SITES...THE OVERNIGHT HOURS WILL SEE A
REDUCTION IN PRECIPITATION CHANCES...BUT LOW CLOUDS (MVFR
CEILINGS) WILL LIKELY SETTLE INTO THE AREA. FOR CINCINNATI...IT
APPEARS THAT RAIN CHANCES WILL CONTINUE THROUGH THE OVERNIGHT
HOURS...WHICH COULD LEAD TO MVFR VISIBILITIES AS WELL AS CEILINGS.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO TUESDAY MORNING.
THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES THROUGH
WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...CONIGLIO/HICKMAN
SHORT TERM...HICKMAN
LONG TERM...HICKMAN/JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
646 AM EDT MON APR 30 2012
.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH ACROSS THE AREA TODAY. AN UPPER LEVEL
WEATHER DISTURBANCE WILL COMBINE WITH A WEAK COLD FRONT TONIGHT TO
PRODUCE SHOWERS AND THUNDERSTORMS. EMBEDDED DISTURBANCES ALOFT
WILL CONTINUE TO RIPPLE ACROSS THE REGION THROUGH MID
WEEK...KEEPING THE THREAT OF SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE USED A BLEND OF THE GFS/ECMWF AS THE NAM-WRF HAS TOO MANY
NEGATIVE FEEDBACK ISSUES DUE TO CONVECTION.
SOUTHWESTERLY FLOW ALOFT IS UNDERWAY THIS MORNING. THIS PATTERN
WILL LIFT A WARM FRONT NORTHWARD ACROSS THE REGION THROUGH EARLY
AFTN. A MUCH WARMER AND MORE HUMID AIRMASS CAN BE EXPECTED IN THE
WAKE OF THIS FRONT...MORE LIKE LATE JUNE WEATHER THAN THE END OF
APRIL. A FEW SHOWERS AND THUNDERSTORMS MAY OCCUR AS THE WARM FRONT
PASSES BY. THEN...EYES TURN TOWARD THE WEST AS A WEAK AREA OF LOW
PRESSURE IS FORECAST TO TRAVERSE ACROSS NRN INDIANA INTO NW OHIO
LATE IN THE DAY. A WEAK COLD FRONT WILL BEGIN TO SAG TOWARD THE NW
CWFA LATE IN THE DAY...INCREASING THE THREAT OF SHOWERS AND STORMS
THERE. FOR THE REMAINDER OF THE AREA...THE MAIN PCPN THREAT IS
EXPECTED THIS EVENING AND OVERNIGHT AND WILL BE DISCUSSED IN THE
SHORT TERM SECTION. CLOUDS AND PCPN WILL KEEP TEMPERATURES COOLER
ACROSS THE NW. HIGHS WILL RANGE FROM THE LOWER 70S FAR NORTHWEST
TO THE MID 80S SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
AN EMBEDDED S/WV IS FORECAST TO MOVE ACRS THE REGION OVERNIGHT. IT
IS UNCLEAR IF CONVECTION WILL GET GOING NEAR THE WEAK COLD FRONT
TO OUR NW LATE IN THE DAY...THEN PROPAGATE ESE TOWARD THE BETTER
AXIS OF INSTABILITY OR PERHAPS DEVELOP NEAR A SUBTLE WEAK
PREFRONTAL TROF AS THE LATEST HRRR SUGGESTS. IN EITHER
CASE...CONVECTION SHOULD INCREASE THIS EVENING AS THE S/WV ALOFT
INTERACTS WITH MODERATE INSTABILITY. MODELS SUGGEST THAT THE S/WV
WILL BE ASSOCIATED WITH A 50 TO 60 KNOT MID LVL JET. THE
COMBINATION OF SHEAR AND INSTABILITY SHOULD RESULT IN MUTICELLULAR
CLUSTERS THAT MAY MERGE INTO LINES AND/OR BOWING SEGMENTS. A
SUPERCELL CAN NOT BE RULED OUT EITHER. THE THREAT FOR SOME SEVERE
STORMS WILL BE THERE WITH DAMAGING WIND AND LARGE HAIL BEING THE
PRIMARY SEVERE WEATHER THREATS. WILL EMPHASIZE THIS THREAT IN THE
HWO. STORMS SHOULD HAVE ENOUGH MOVEMENT TO PREVENT A SIGNIFICANT
FLOOD THREAT...BUT WITH PWATS INCREASING TO 1.50 INCHES...HEAVY
RAIN AND LOCALIZED FLOODING ARE A POSSIBILITY. GIVEN STATED
PARAMETERS ABOVE...HAVE CONTINUED WITH LIKELY POPS TONIGHT AS
CONVECTION SHOULD MOVE ESE THROUGH THE OVERNIGHT HOURS. OVERNIGHT
LOWS WILL RANGE FROM THE UPPER 50S TO THE LOWER 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
THE WEAK COLD FRONT IS FORECAST TO STALL NEAR THE NRN CWFA BY
TUESDAY MORNING. IN A WARM AND UNSTABLE AIRMASS...WILL CONTINUE
WITH CHANCE POPS ON TUESDAY. A BETTER CHANCE OF SHOWERS AND STORMS
MAY OCCUR LATE TUESDAY AFTERNOON AND OVERNIGHT AS ANOTHER EMBEDDED
DISTURBANCE RIPPLES BY ALOFT. THERE APPEARS TO BE LESS SHEAR AND
LOW LEVEL FOCUS WITH THIS ROUND OF PCPN AS WELL AS WEAKER
INSTABILITY SO THE SEVERE THREAT WILL BE MARGINAL. GIVEN
APPRECIABLE PWATS...THE THREAT OF LOCALIZED FLOODING WILL
CONTINUE. HIGHS ON TUESDAY WILL BE A LITTLE COOLER GIVEN CLOUDS
AND SHOULD RANGE FROM THE MID TO UPPER 70S. LOWS TUESDAY NIGHT
WILL FALL INTO THE LOWER 60S.
DEEPER MOISTURE WILL PIVOT NE ON WEDNESDAY AS S/WV MOVES OFF TO
THE EAST. THIS SHOULD ALLOW FOR A DECREASING THREAT OF SHOWERS AND
THUNDERSTORMS FROM WEST TO EAST THROUGH THE DAY. WARM TEMPERATURES
WILL OCCUR WITH HIGHS IN THE LOWER TO MID 80S.
FOR WEDNESDAY NIGHT INTO THURSDAY...MODELS TRY TO BUILD A MID LVL
RIDGE FROM THE SE U.S. NORTH AND WESTWARD INTO THE OHIO VALLEY.
THIS SHOULD GIVE THE REGION A DRY PERIOD ALONG WITH PERHAPS THE
WARMEST TEMPERATURES OF THE WEEK WITH MOST LOCATIONS REACHING INTO
THE MID 80S.
SEVERAL DISTURBANCES ALOFT ARE FORECAST TO RIDE UP THE BACK SIDE
OF THE MID LVL RIDGE THURSDAY NIGHT INTO FRIDAY AND THIS WILL
EVENTUALLY HELP FLATTEN OUT THE RIDGE. THIS WILL ALSO ALLOW FOR A
COLD FRONT TO SAG DOWN FROM THE NORTH AND POSSIBLY LAY OUT ACROSS
OUR AREA FRIDAY INTO SATURDAY. AS THE RIDGE BEGINS TO BREAK
DOWN...WILL ALLOW FOR A CHANCE OF SHOWERS AND THUNDERSTORMS TO
PUSH DOWN INTO OUR AREA THURSDAY NIGHT INTO FRIDAY. HOW LONG THE
PCPN THREAT LINGERS WILL DEPEND ON EXACTLY HOW FAR SOUTH THE
BOUNDARY IS ABLE TO PUSH. FOR NOW WILL SLOWLY TAPER POPS OFF FROM
THE NORTH HEADING INTO SATURDAY. TEMPERATURES WILL ALSO BE
DEPENDENT ON THE PLACEMENT AND TIMING OF THE BOUNDARY. WILL
SLOWLY DECREASE TEMPERATURES THROUGH THE REMAINDER OF THE
EXTENDED PERIOD AS THE UPPER LEVEL RIDGE BEGINS TO WEAKEN AND THE
POSSIBILITY OF SOME PCPN DEVELOPS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A WARM FRONT IS CURRENTLY PUSHING NORTH OF THE TAF SITES...WHICH
SHOULD END PRECIPITATION CHANCES FOR THE MORNING. SHOWERS NEAR
COLUMBUS WILL HAVE MOVED AWAY...LEAVING THE CWA IN THE BUILDING
WARM SECTOR FOR THE FIRST HALF OF THE DAY. WINDS WILL GRADUALLY
SHIFT TO THE SOUTHWEST...WITH GUSTS OF UP TO 20 KNOTS EXPECTED
THROUGH THE AFTERNOON HOURS.
THE CHANCES FOR SHOWERS AND THUNDERSTORMS WILL BEGIN TO INCREASE
BY LATE AFTERNOON...WITH THE BEST CHANCES COMING DURING THE
EVENING HOURS. THERE IS HIGH CONFIDENCE IN PRECIPITATION AFFECTING
THE TAF SITES...WITH THUNDER EXPECTED AS WELL. EXACT TIMING IS NOT
CERTAIN RIGHT NOW...BUT THERE WILL LIKELY BE PERIODS OF REDUCED
AVIATION CONDITIONS...AND POSSIBLY STRONG STORMS AS WELL.
FOR THE NORTHERN TAF SITES...THE OVERNIGHT HOURS WILL SEE A
REDUCTION IN PRECIPITATION CHANCES...BUT LOW CLOUDS (MVFR
CEILINGS) WILL LIKELY SETTLE INTO THE AREA. FOR CINCINNATI...IT
APPEARS THAT RAIN CHANCES WILL CONTINUE THROUGH THE OVERNIGHT
HOURS...WHICH COULD LEAD TO MVFR VISIBILITIES AS WELL AS CEILINGS.
OUTLOOK...MVFR CEILINGS MAY CONTINUE INTO TUESDAY MORNING.
THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE AT TIMES THROUGH
WEDNESDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...HICKMAN/JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS TULSA OK
1040 AM CDT MON APR 30 2012
...UPDATE...
.DISCUSSION...
MORNING THUNDERSTORMS CONTINUE TO PUSH OFF TO THE EAST...AND WILL
LIKELY BE OUT OF THE FORECAST AREA BY 18Z. FORECAST WILL BE
UPDATED AT LEAST ONCE THIS AFTERNOON AFTER THESE STORMS HAVE
TOTALLY CLEARED THE AREA. ADDITIONAL THUNDERSTORM DEVELOPMENT THIS
AFTERNOON IS HINTED AT BY BOTH THE HRRR AND THE LOCAL WRF...MAINLY
ACROSS NORTHEAST OKLAHOMA. HAVE RETOOLED POPS TO SHOW HIGHER
VALUES NEAR THE KANSAS BORDER...TAPERING TO LOWER VALUES SOUTH OF
INTERSTATE 40.
SOME CLEARING IS OCCURRING ON THE BACKSIDE OF THE STORMS...AND IF
THIS TREND CONTINUES ACROSS THE SOUTHEASTERN HALF OF THE
AREA...FORECAST HIGHS SHOULD STILL BE REALIZED. WILL NOT CHANGE
HIGHS ATTM...BUT WILL CONTINUE TO MONITOR AND MAKE ADJUSTMENTS AS
NEEDED BEFORE ANY AFTERNOON UPDATES.
TWEAKS HAVE BEEN MADE TO OTHER ELEMENTS ACCORDING TO CURRENT
TRENDS.
&&
.PREV DISCUSSION... /ISSUED 624 AM CDT MON APR 30 2012/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
LINE OF THUNDERSTORMS WITH TRAILING AREA OF STRATIFORM RAIN WILL
CONTINUE TO PROGRESS EAST THIS MORNING...WILL BE ONGOING AT
MLC/FSM/FYV AT ISSUANCE TIME WITH MVFR CONDITIONS PREVAILING. ONCE
THIS CLEARS THE AREA...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH
THE REST OF THE PERIOD. CONFIDENCE REGARDING ADDITIONAL
THUNDERSTORM DEVELOPMENT THIS AFTERNOON ALONG ANY OUTFLOW BOUNDARY
REMAINS TOO LOW AT THIS POINT TO INCLUDE ANY MENTION IN THE
FORECAST. SHOULD ANY STORMS OCCUR...LOCAL MVFR CONDITIONS WILL BE
LIKELY.
PREV DISCUSSION... /ISSUED 329 AM CDT MON APR 30 2012/
DISCUSSION...
A WEAKENING AREA OF SHOWERS AND THUNDERSTORMS IS PROGRESSING
SOUTHEAST ACROSS NORTHEAST OKLAHOMA EARLY THIS MORNING AND LATEST
RUNS OF THE HRRR SUGGEST THAT AT LEAST A BROKEN BAND OF SHOWERS
AND STORMS WILL MAKE IT THROUGH ALL OF EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS THIS MORNING. RESIDUAL OUTFLOW BOUNDARIES AND
THE OLD FRONTAL BOUNDARY NEAR THE KANSAS AND MISSOURI BORDERS MAY
PROVIDE A FOCUS FOR RENEWED DEVELOPMENT LATER THIS AFTERNOON OR
THIS EVENING BUT BY LATER TONIGHT THE GREATEST CONVECTIVE COVERAGE
IS LIKELY TO BE TO OUR NORTH AND NORTHEAST.
WILL CONTINUE LOW POPS INTO TUESDAY BUT AFTER THAT THE CAPPING
INVERSION STRENGTHENS ENOUGH TO PRECLUDE A MENTION OF CONVECTION.
VERY WARM AND HUMID WEATHER WILL THEN PREVAIL THROUGH AT LEAST
NEXT WEEKEND WITH HIGHS APPROACHING 90 AND LOWS NEAR 70 IN MANY
PLACES.
STAYED CLOSE TO THE WARMER NAM MOS TEMPERATURES THE NEXT COUPLE
DAYS.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...22
LONG TERM....23
AREA FORECAST DISCUSSION
NWS TULSA OK
624 AM CDT MON APR 30 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
LINE OF THUNDERSTORMS WITH TRAILING AREA OF STRATIFORM RAIN WILL
CONTINUE TO PROGRESS EAST THIS MORNING...WILL BE ONGOING AT
MLC/FSM/FYV AT ISSUANCE TIME WITH MVFR CONDITIONS PREVAILING. ONCE
THIS CLEARS THE AREA...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH
THE REST OF THE PERIOD. CONFIDENCE REGARDING ADDITIONAL
THUNDERSTORM DEVELOPMENT THIS AFTERNOON ALONG ANY OUTFLOW BOUNDARY
REMAINS TOO LOW AT THIS POINT TO INCLUDE ANY MENTION IN THE
FORECAST. SHOULD ANY STORMS OCCUR...LOCAL MVFR CONDITIONS WILL BE
LIKELY.
&&
.PREV DISCUSSION... /ISSUED 329 AM CDT MON APR 30 2012/
DISCUSSION...
A WEAKENING AREA OF SHOWERS AND THUNDERSTORMS IS PROGRESSING
SOUTHEAST ACROSS NORTHEAST OKLAHOMA EARLY THIS MORNING AND LATEST
RUNS OF THE HRRR SUGGEST THAT AT LEAST A BROKEN BAND OF SHOWERS
AND STORMS WILL MAKE IT THROUGH ALL OF EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS THIS MORNING. RESIDUAL OUTFLOW BOUNDARIES AND
THE OLD FRONTAL BOUNDARY NEAR THE KANSAS AND MISSOURI BORDERS MAY
PROVIDE A FOCUS FOR RENEWED DEVELOPMENT LATER THIS AFTERNOON OR
THIS EVENING BUT BY LATER TONIGHT THE GREATEST CONVECTIVE COVERAGE
IS LIKELY TO BE TO OUR NORTH AND NORTHEAST.
WILL CONTINUE LOW POPS INTO TUESDAY BUT AFTER THAT THE CAPPING
INVERSION STRENGTHENS ENOUGH TO PRECLUDE A MENTION OF CONVECTION.
VERY WARM AND HUMID WEATHER WILL THEN PREVAIL THROUGH AT LEAST
NEXT WEEKEND WITH HIGHS APPROACHING 90 AND LOWS NEAR 70 IN MANY
PLACES.
STAYED CLOSE TO THE WARMER NAM MOS TEMPERATURES THE NEXT COUPLE
DAYS.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
902 AM CDT MON APR 30 2012
.SHORT TERM...THIS MORNING
902 AM CDT MON APR 30 2012
VISIBILITIES ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN HAVE
IMPROVED TO 3 MILES OR HIGHER. DUE TO THIS...THE DENSE FOG
ADVISORY HAS BEEN CANCELLED EARLY.
.LONG TERM...THURSDAY THROUGH SUNDAY
351 AM CDT MON APR 30 2012
AN UNSETTLED PATTERN WILL PERSIST ACROSS THE AREA THROUGH THE END
OF THE WORK WEEK AND INTO THE WEEKEND. EMBEDDED SHORTWAVES IN
SOUTHWEST FLOW ALOFT WILL BRING DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 70S
THROUGH SATURDAY...BEFORE A FRONTAL BOUNDARY SLIPS THROUGH THE
REGION SATURDAY NIGHT INTO SUNDAY. SEVERE THUNDERSTORMS REMAIN A
POSSIBILITY THURSDAY THROUGH SATURDAY NIGHT WITH SUFFICIENT SHEAR
AND CAPE IN PLACE. EXACT DETAILS ARE DIFFICULT TO NAIL DOWN THIS
FAR OUT...BUT WILL HAVE TO KEEP A CLOSE WATCH ON THIS. HIGHS ARE
EXPECTED TO FALL INTO THE 60S ON SUNDAY. OVERNIGHT LOWS THROUGH
THE PERIOD WILL RANGE FROM THE MID TO LOWER 50S ACROSS NORTH
CENTRAL WISCONSIN TO AROUND 60 ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN.
&&
.AVIATION...TODAY AND TONIGHT
632 AM CDT MON APR 30 2012
FOG AND STRATUS WERE AFFECTING THE TAF SITES EARLY THIS MORNING IN
THE WAKE OF THE RAIN THAT FELL OVERNIGHT. WITH WEAK HIGH PRESSURE
AND MOISTURE TRAPPED UNDER THE INVERSION...EXPECT IFR CONDITIONS TO
PREVAIL THROUGH 15Z-16Z. AFTER THAT...30.09Z RUC AND NAM BUFKIT
SOUNDINGS SHOW CEILINGS WILL RISE INTO THE MVFR CATEGORY AFTER
15Z-16Z AND EVENTUALLY SCATTER OUT BETWEEN 20Z-23Z. VFR CONDITIONS
THEN EXPECTED THROUGH THE REMAINDER OF THE TAF PERIOD...WITH ONLY
SOME MIDDLE CLOUDS PUSHING IN LATER TONIGHT AFTER 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
901 AM CDT MON APR 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
632 AM CDT MON APR 30 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY
351 AM CDT MON APR 30 2012
MAIN FORECAST CONCERNS ARE ON AREAS OF DENSE FOG ACROSS NORTHEAST
IOWA AND FAR SOUTHWEST WISCONSIN EARLY THIS MORNING. FOCUS THEN
TURNS TO SHOWER/THUNDERSTORM CHANCES TUESDAY THROUGH
WEDNESDAY...WITH THE POTENTIAL FOR A FEW ROUNDS OF SEVERE WEATHER.
CURRENT WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH OVER NORTHERN
WISCONSIN...MOVING NORTHEAST. THIS FEATURE MOVED ACROSS THE FORECAST
AREA OVERNIGHT AND WAS RESPONSIBLE FOR PRODUCING THE RAINFALL DURING
THE LATE EVENING AND OVERNIGHT HOURS.
AREAS OF DENSE FOG ARE EXPECTED THROUGH THE MID MORNING HOURS ACROSS
NORTHEAST IOWA INTO FAR SOUTHWEST WISCONSIN. HAVE ISSUED A DENSE
FOG ADVISORY FOR THESE AREAS THROUGH 10 AM THIS MORNING. OTHERWISE...PLAN
ON MOSTLY CLOUDY SKIES THROUGH THE LATE MORNING HOURS TODAY BEFORE
DRIER AIR ADVECTS INTO THE REGION FROM THE WEST DURING THE
AFTERNOON HOURS. PLAN ON PARTLY SUNNY SKIES BY LATE THIS
AFTERNOON. QUIET CONDITIONS ARE EXPECTED TODAY WITH ZONAL FLOW
ALOFT ACROSS THE AREA. WARMER TEMPERATURES ARE EXPECTED TODAY WITH
HIGHS RANGING FROM THE LOWER 60S ACROSS NORTH CENTRAL WISCONSIN TO
THE MID 60S ACROSS SOUTHEAST MINNESOTA INTO NORTHEAST IOWA. AN
UPPER LEVEL TROUGH WILL PUSH INTO THE PACIFIC NORTHWEST TONIGHT
AND HEAD EAST INTO THE DAKOTAS AND CENTRAL PLAINS EARLY TUESDAY.
FLOW ALOFT WILL SWITCH TO THE SOUTHWEST AS THE TROUGH EDGES
EASTWARD. THIS WILL SET THE STAGE FOR AN ACTIVE WEATHER PATTERN
ACROSS THE UPPER MISSISSIPPI RIVER VALLEY OVER THE NEXT FEW DAYS
AS SEVERAL EMBEDDED SHORTWAVE IMPULSES MOVE ACROSS THE AREA.
MOIST AND WARM SOUTHERLY FLOW WILL SET UP ACROSS THE REGION ON
TUESDAY. A WEAK SHORTWAVE LOOKS TO PUSH ACROSS THE AREA DURING THE
DAY ON TUESDAY. THERE IS THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS
THROUGH THE DAY ON TUESDAY AS THIS FEATURE MOVES THROUGH. OVERALL
INSTABILITY LOOKS LIMITED DURING THE DAY ON TUESDAY...WITH
FORECAST SOUNDINGS SHOWING 300 TO 500 J/KG SURFACE BASED CAPE.
SEVERE THUNDERSTORMS ARE NOT EXPECTED DURING THE DAY ON TUESDAY BUT
CANNOT RULE OUT A FEW SHOWERS AND THUNDERSTORMS ACROSS THE AREA ON
TUESDAY AS THE WAVE MOVES THROUGH. SO WILL MAINTAIN A SLIGHT CHANCE
OF SHOWERS AND THUNDERSTORMS ACROSS THE AREA. IT WILL BE BREEZY
ACROSS THE AREA ON TUESDAY...WITH SOUTH WINDS AT 15 TO 25 MPH. WINDS
COULD GUST TO AROUND 35 MPH AT TIMES...ESPECIALLY IN OPEN AREAS.
THE BULK OF THE INSTABILITY WILL BE ACROSS CENTRAL
MINNESOTA...WESTERN IOWA...EASTERN NEBRASKA. THIS AREA LOOKS TO BE A
RIPE ENVIRONMENT FOR THUNDERSTORM DEVELOPMENT TUESDAY AFTERNOON WITH
0-3 KM MOST UNSTABLE CAPE VALUES IN EXCESS OF 2000 J/KG AND 0-6 KM
BULK SHEAR VALUES OF 40 TO 50 KTS. 850 MB MOISTURE TRANSPORT WILL
RAPIDLY INTENSIFY ACROSS THE FORECAST AREA TUESDAY NIGHT. WOULD
EXPECT TO SEE A THUNDERSTORM COMPLEX DEVELOP ACROSS SOUTHWEST INTO
CENTRAL MINNESOTA LATE TUESDAY AFTERNOON...THEN MOVING EASTWARD
TUESDAY EVENING INTO SOUTHEAST MINNESOTA AND PORTIONS OF NORTHEAST
IOWA. MUCAPE VALUES INCREASE ACROSS THE FORECAST AREA TUESDAY
EVENING...INTO THE 1500 TO 2000 J/KG RANGE. FORECAST SOUNDINGS
GENERATE AROUND 1300 J/KG ELEVATED CAPE WHEN LIFTING FROM AROUND
2500 FT...WITH NO CAP IN PLACE. OVERALL SHEAR LOOKS LIMITED...WHEN
LIFTING FROM THIS LEVEL WITH 2-7 KM BULK SHEAR VALUES OF 20 TO 30
KTS. OVERALL STORM ORGANIZATION IS IN QUESTION BUT THINKING THERE
IS THE POSSIBILITY OF SEEING A FEW STRONG TO SEVERE THUNDERSTORMS.
PRECIPITABLE WATER IS EXPECTED TO INCREASE TO AROUND 250 PERCENT
OF NORMAL...WITH PRECIPITABLE WATER VALUES RUNNING AROUND 1.6
INCHES. WILL HAVE TO KEEP A WATCH OUT FOR BRIEF HEAVY RAIN WITH
ANY THUNDERSTORMS THAT DEVELOP TUESDAY NIGHT THROUGH WEDNESDAY
MORNING. PLAN ON SHOWERS AND THUNDERSTORMS PERSISTING INTO
WEDNESDAY MORNING. AT THIS TIME THE MAIN HAZARDS TUESDAY NIGHT
THROUGH WEDNESDAY MORNING APPEAR TO BE LARGE HAIL...DAMAGING
WINDS...AND HEAVY RAIN.
FORECAST MODELS ARE INDICATING ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING. THE MAIN
CONCERN IS HOW MUCH THE ATMOSPHERE WILL RECOVER FROM THE EARLY
MORNING CONVECTION AND HOW MUCH SURFACE HEATING IS REALIZED TO
OVERCOME A CAP. WARM MOIST SOUTHERLY FLOW WILL CONTINUE ACROSS THE
AREA ON WEDNESDAY. SHOULD SEE ANOTHER ROUND OF SHOWERS AND
THUNDERSTORMS DEVELOP WEDNESDAY AFTERNOON. PRETTY IMPRESSIVE SURFACE
BASED CAPE VALUES WEDNESDAY AFTERNOON...WITH CAPE INCREASING TO
AROUND 2500 J/KG. HOWEVER...THERE IS A SMALL CAP TO OVERCOME WITH
CIN VALUES AROUND -150 J/KG. A WEAK SHORTWAVE LOOKS TO MOVE ACROSS
THE REGION LATE IN THE AFTERNOON INTO THE EARLY EVENING HOURS AND
SHOULD BE ENOUGH TO GENERATE THUNDERSTORM. 0-6 KM BULK SHEAR VALUES
WILL BE IN THE 30 TO 40 KT RANGE...SO THE POTENTIAL EXISTS FOR
ANOTHER ROUND OF STRONG TO SEVERE THUNDERSTORMS. DETAILS ON TIMING
AND PLACEMENT OF THE BOUNDARIES LEFT OVER FROM TUESDAY
NIGHT/WEDNESDAY MORNING CONVECTION WILL DETERMINE WHEN AND WHERE
SHOWERS AND THUNDERSTORMS DEVELOP. FORECAST MODELS HAVING SOME
PLACEMENT ISSUES ON WHERE THE CONVECTION FIRES SO WILL HAVE TO KEEP
A CLOSE WATCH ON THIS THE NEXT SET OF RUNS. AT THIS TIME THE MAIN
THREATS LOOK TO BE LARGE HAIL AND DAMAGING WINDS. DEPENDING ON THE
POSITION OF LOW LEVEL BOUNDARIES FROM THE OVERNIGHT CONVECTION...AND
A WARM FRONTAL BOUNDARY EXPECTED TO BE DRAPED ACROSS THE
REGION...AN ISOLATED TORNADO OR TWO CANNOT BE RULED OUT WEDNESDAY
AFTERNOON INTO EARLY WEDNESDAY EVENING.
SHOWERS AND THUNDERSTORM CHANCES WILL CONTINUE WEDNESDAY NIGHT INTO
THURSDAY AS THE SOUTHWEST FLOW ALOFT PERSISTS ACROSS THE REGION.
HIGH TEMPERATURES WILL REMAIN IN THE 70S WITH LOWS IN THE UPPER 50S
TO AROUND 60.
.LONG TERM...THURSDAY THROUGH SUNDAY
351 AM CDT MON APR 30 2012
AN UNSETTLED PATTERN WILL PERSIST ACROSS THE AREA THROUGH THE END
OF THE WORK WEEK AND INTO THE WEEKEND. EMBEDDED SHORTWAVES IN
SOUTHWEST FLOW ALOFT WILL BRING DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 70S
THROUGH SATURDAY...BEFORE A FRONTAL BOUNDARY SLIPS THROUGH THE
REGION SATURDAY NIGHT INTO SUNDAY. SEVERE THUNDERSTORMS REMAIN A
POSSIBILITY THURSDAY THROUGH SATURDAY NIGHT WITH SUFFICIENT SHEAR
AND CAPE IN PLACE. EXACT DETAILS ARE DIFFICULT TO NAIL DOWN THIS
FAR OUT...BUT WILL HAVE TO KEEP A CLOSE WATCH ON THIS. HIGHS ARE
EXPECTED TO FALL INTO THE 60S ON SUNDAY. OVERNIGHT LOWS THROUGH
THE PERIOD WILL RANGE FROM THE MID TO LOWER 50S ACROSS NORTH
CENTRAL WISCONSIN TO AROUND 60 ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN.
&&
.AVIATION...TODAY AND TONIGHT
632 AM CDT MON APR 30 2012
FOG AND STRATUS WERE AFFECTING THE TAF SITES EARLY THIS MORNING IN
THE WAKE OF THE RAIN THAT FELL OVERNIGHT. WITH WEAK HIGH PRESSURE
AND MOISTURE TRAPPED UNDER THE INVERSION...EXPECT IFR CONDITIONS TO
PREVAIL THROUGH 15Z-16Z. AFTER THAT...30.09Z RUC AND NAM BUFKIT
SOUNDINGS SHOW CEILINGS WILL RISE INTO THE MVFR CATEGORY AFTER
15Z-16Z AND EVENTUALLY SCATTER OUT BETWEEN 20Z-23Z. VFR CONDITIONS
THEN EXPECTED THROUGH THE REMAINDER OF THE TAF PERIOD...WITH ONLY
SOME MIDDLE CLOUDS PUSHING IN LATER TONIGHT AFTER 06Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
351 AM CDT MON APR 30 2012
WI...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR WIZ054-061.
MN...NONE.
IA...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS PUEBLO CO
315 PM MDT MON APR 30 2012
.SHORT TERM...
(TONIGHT AND TUESDAY)
THE MAIN CONCERN IS THE POTENTIAL FOR SOME TSTMS...POSSIBLY
SEVERE...OVER THE FAR SERN PORTION OF THE STATE. DEW POINTS OVR THE
SERN CORNER OF THE STATE ARE STILL AROUND 50 F AND THE NAM12 SHOWS
THE 50S GETTING TO ABOUT THE STATE LINE BY 00Z AND THEN BACKING INTO
THE AREA AGAIN THIS EVENING. SATELLITE IMAGES SHOWING CU
DEVELOPMENT OVR ERN LAS ANIMAS...BACA AND PORTIONS OF PROWERS
COUNTIES...AND HAVE HAD ONE CELL SHOW UP ON RADAR OVR NERN NM SO FAR
THIS AFTERNOON. LATEST MESOSCALE ANALYSIS SHOWS 1000-1500 J/KG OF
CAPE OVR BACA COUNTY...WITH LI/S OF -3 TO -5C. THE NAM12 CONTINUES
TO KEEP THE CWA DRY THIS EVENING...WHILE THE HRRR SHOWS THE
POTENTIAL FOR SOME PCPN THIS EARLY EVENING OVR BACA COUNTY. A WEAK
SHORTWAVE TROF WL ALSO BE MOVING ACRS THE AREA...AND WITH THE DRY
LINE EXPECTED TO BE OVR OR NR THE SE PORTION OF THE STATE...WE COULD
SEE SOME THUNDERSTORMS DEVELOP OR MOVE INTO THAT AREA SO WL GO WITH
SOME ISOLD POPS. THUNDERSTORMS IN THAT AREA WL HAVE THE POTENTIAL
TO PRODUCE LARGE HAIL AND STRONG WINDS.
LATER TONIGHT CONVECTION SHOULD END AND THERE MAY JUST BE SOME HIGH
CLOUDS. ON TUESDAY...GENERALLY DRY WESTERLY FLOW ALOFT WL BE OVR
THE AREA...HOWEVER A SHORTWAVE TROF MOVING BY TO THE NORTH OF THE
AREA...COULD BRING SOME SHOWERS TO THE CENTRAL MTS. THE NAM KEEPS
PCPN JUST NORTH OF THE AREA...WHILE THE GFS PRINTS OUT SOME QPF
ALONG THE CONTDVD. HIGHS ON TUE SHOULD BE WELL ABOVE NORMAL OVR
MOST OF THE AREA.
.LONG TERM...
(TUESDAY NIGHT THROUGH MONDAY)
MODELS STILL IN GOOD AGREEMENT THROUGH SATURDAY WITH UNCERTAINTY
HEADING INTO EARLY NEXT WEEK. THE PATTERN WILL BE CHARACTERIZED BY
BROAD TROUGHING OVER THE NORTHERN CONUS WITH SEVERAL DISTURBANCES
MOVING ACROSS THE ROCKIES THROUGH SATURDAY.
MODELS BRING A WEAK DISTURBANCE ACROSS THE ROCKIES PRETTY MUCH
EVERY DAY WEDNESDAY THROUGH FRIDAY. THE NORTHERLY TRACKS WILL KEEP
SHOWER AND THUNDERSTORM ACTIVITY CONFINED TO THE CENTRAL
MOUNTAINS. EXPECT ISOLATED CONVECTION TUESDAY EVENING WHICH WILL
QUICKLY DIE OUT AFTER SUNSET. MODELS INDICATING THE BEST CHANCE
FOR MORE WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY BEING
WEDNESDAY. AGAIN THE CENTRAL MOUNTAINS WILL BE THE FOCUS...WITH
THUNDERSTORMS POSSIBLE OVER THE LA GARITA RANGE AND SPREADING EAST
INTO THE NORTHERN SANGRES AND RAMPART RANGES DURING THE AFTERNOON.
SOME MODELS ARE BRINGING THIS SHOWER ACTIVITY OFF THE MOUNTAINS
AND INTO THE PALMER DIVIDE WEDNESDAY EVENING. THE WEAK SYSTEM
RESPONSIBLE FOR THIS SHOWER ACTIVITY WILL SHIFT EAST QUICKLY WITH
ALL SHOWER AND THUNDERSTORM ACTIVITY COMING TO AN END BY MIDNIGHT.
ANOTHER WEAK DISTURBANCE WILL SHIFT ACROSS THE NORTHERN ROCKIES ON
THURSDAY WITH ANOTHER ROUND OF ISOLATED SHOWERS AND THUNDERSTORMS
FOR THE CENTRAL MOUNTAINS. THE PERSISTENT SOUTHWESTERLY TO
WESTERLY FLOW WILL KEEP MIXING GOING OVER THE LOWER ELEVATIONS
WITH TEMPERATURES WELL INTO THE 80S EACH AFTERNOON.
THE PATTERN BEGINS TO BECOME MORE AMPLIFIED FRIDAY INTO SATURDAY
WITH LOW PRESSURE DEVELOPING OVER THE PACIFIC NORTHWEST AND HIGH
PRESSURE OVER THE CENTRAL PLAINS. THIS WILL TURN FLOW MORE
SOUTHWESTERLY WITH DRY WARM CONDITIONS FOR SOUTHERN COLORADO. AT
THIS TIME MOISTURE LOOKS LIMITED WHICH WILL LIKELY KEEP CONVECTION
TO A MINIMUM OVER THE CONTINENTAL DIVIDE WITH JUST CUMULUS BUILD
UPS EXPECTED. BEYOND SATURDAY...DIFFERENCES BEGIN TO ARISE
BETWEEN THE ECMWF AND THE INCONSISTENT GFS. THE ECMWF DROPS THE
PACIFIC NORTHWEST SYSTEM INTO THE GREAT BASIN WHERE IT IS FORECAST
TO SIT INTO EARLY NEXT WEEK. MEANWHILE CANADIAN HIGH PRESSURE WILL
SEND A FRONT INTO EASTERN COLORADO WITH COOL UPSLOPE FLOW AND
WIDESPREAD SHOWER ACTIVITY. THE GFS HAS SHOWN THIS SOLUTION EVERY
OTHER MODEL RUN...BUT HAS BEEN VERY INCONSISTENT. THE 12Z GFS RUN
HAS THE UPPER LOW REMAINING OVER THE PACIFIC NORTHWEST WITH
STRONGER SOUTHWESTERLY FLOW WHICH WILL KEEP THE CANADIAN HIGH
CENTERED FURTHER NORTH. THIS WILL KEEP THE SURFACE FRONT TO THE
NORTH WITH DRY WESTERLY FLOW OVERHEAD. DO FEEL THAT AT SOME POINT
IN EARLY TO MID NEXT WEEK...THE FRONT WILL MAKE IT THROUGH BUT
CONFIDENCE IS LOW IN WHEN...AND HOW MUCH PRECIP WE WILL RECEIVE
WHEN IT DOES. MOZLEY
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED AT THE TAF SITES TONIGHT AND
TUESDAY...AS GENERALLY DRY WESTERLY FLOW IS EXPECTED OVER THE AREA.
SOUTH TO SOUTHWEST WINDS AT 15-25 KTS ARE EXPECTED MOSTLY AFTER 18Z
ON TUE.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
28/88
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
215 PM EDT MON APR 30 2012
.SYNOPSIS...
18Z WATER VAPOR AND H4 RUC ANALYSIS SHOWS A SOMEWHAT UNAMPLIFIED
UPPER LEVEL PATTERN IN PLACE ACROSS THE CONUS THIS MORNING. NORTHERN
STREAM FLOW ARRIVES OVER THE PACIFIC NORTHWEST COAST AND REMAINS
RATHER ZONAL OVER THE INTER-MOUNTAIN WEST/HIGH PLAINS. THE FLOW THEN
BENDS NORTHWARD INTO SHARP RIDGING OVER THE NORTHEASTERN STATES.
WEAK IMPULSES RIDING ALONG WITH THE FLOW HAVE BEEN PRODUCING
PERIODIC BURST OF CONVECTION OVER THE MID-SECTION OF THE COUNTY AS
THEY EJECT OUT OVER THE CENTRAL PLAINS. MORE OF THESE CONVECTIVE
BURSTS ARE EXPECTED TODAY WITH LOCALLY STRONG STORMS AND FLOODING
RAINFALL. CLOSER TO HOME...THE UPPER LEVEL PATTERN IS SIMILAR TO
WHAT HAS BEEN OBSERVED FOR THE PAST COUPLE OF DAYS. UPPER LEVEL
RIDGING REMAINS IN PLACE FROM THE NORTH-CENTRAL GULF COAST TO THE
CAROLINAS...WHILE AN UPPER LEVEL DISTURBANCE SPINS FROM THE FL
STRAITS TO THE BAHAMAS. DEEP LAYER MOISTURE IS CONFINED IN CLOSE
PROXIMITY TO THIS UPPER DISTURBANCE...GENERALLY SOUTH AND EAST OF
THE TAMPA BAY AREA. 12Z KTBW SOUNDING WAS SIGNIFICANTLY DRIER THAN
WHAT WAS OBSERVED AT KMFL WHERE THE COLUMN WAS NEARLY SATURATED
BELOW 400MB. NWP GUIDANCE REMAINS IN AGREEMENT FORECASTING A FURTHER
RETREAT SOUTH AND EAST OF THE MID/HIGH LEVEL MOISTURE THIS EVENING.
AT THE SURFACE...FORECAST AREA REMAINS WEDGED BETWEEN THE
SUBTROPICAL RIDGE AXIS TO OUR NORTH AND AN INVERTED SURFACE TROUGH
SLOWLY MOVING WESTWARD ACROSS THE FL STRAITS/SOUTH FLORIDA
PENINSULA. THIS STUBBORN TROUGH CONTINUES TO SUPPLY THE LOW LEVEL
FOCUS FOR ASCENT WITH SCT-NMRS SHOWERS OVER THE FAR SOUTHERN PORTION
OF THE PENINSULA.
&&
.SHORT TERM (TONIGHT THROUGH WEDNESDAY)...
TONIGHT...
SYNOPTIC PATTERN HOLDS THROUGH TONIGHT KEEPING CHANCES FOR
SHOWERS CONFINED TO THE FAR SOUTHERN PORTIONS OF THE PENINSULA.
ANOTHER WARM NIGHT ON TAP WITH ABUNDANT ATLANTIC MOISTURE HELPING TO
HOLD LOW TEMPERATURES IN THE MIDDLE/UPPER 60S.
TUESDAY THROUGH WEDNESDAY...
SURFACE TROUGH BEGINS TO MAKE SOME WESTWARD PROGRESS TOWARD THE
CENTRAL GULF...WHILE MUCH OF THE UPPER LEVEL ENERGY HOLDS BACK TO
THE WEST. WITH THE UPPER SUPPORT IN PLACE...ANOTHER WET DAY LOOKS TO
BE IN STORE FOR THE FAR SOUTHERN PORTION OF THE PENINSULA. WITH TIME
THE UPPER RIDGE OVER THE SOUTHEASTERN STATES WILL BEGIN TO TRANSLATE
EASTWARD INTO THE ATLANTIC. GFS/ECMWF SHOW AT LEAST SOME DEEP LAYER
MOISTURE RETURN ALONG THE FL WEST COAST IN THE WAKE OF THIS RIDGE.
THE DEEPER MOISTURE AND LESS SUPPRESSION WILL ALLOW SLIGHTLY BETTER
CHANCES FOR SCT AFTERNOON/EVENING SHOWERS FROM TAMPA BAY SOUTHWARD
TUESDAY AFTERNOON/EVENING...AND ONCE AGAIN ON WEDNESDAY. WITH STILL
SOME RESIDUAL INFLUENCE FROM THE UPPER RIDGE...DRY CONDITIONS...AND
THE WARMEST TEMPS (PUSHING 90) WILL BE FOUND NORTH OF THE TAMPA BAY
AREA INTO THE MIDDLE OF THE WEEK.
&&
.LONG TERM (THURSDAY THROUGH NEXT MONDAY)...
THE GLOBAL MODELS BEGIN THE PERIOD WITH AN UPPER LEVEL RIDGE ALONG
THE EASTERN SEABOARD AND A SHORT WAVE TROUGH OVER THE GULF OR GULF
COASTAL REGION. THROUGH THE PERIOD THESE FEATURES SLIDE TO THE WEST
OR NW AS AN UPPER TROUGH MOVES INTO WESTERN ATLANTIC WATERS...OFF
THE EAST U.S. COAST. AT THE SURFACE HIGH PRESSURE CENTERED OVER
THE OPEN ATLANTIC ALONG LATITUDE 30 SLOWLY MOVES WEST...WITH A
RIDGE AXIS INITIALLY REACHING WEST TO THE CENTRAL GULF COAST. BUT
AS THE HIGH CENTER APPROACHES THE RIDGE AXIS WILL SAG IN ACROSS FL
IN RESPONSE TO A FRONTAL BOUNDARY DROPPING INTO THE SE U.S.
DIFFERENCES IN THE MODEL SOLUTIONS CONTINUE AND PREFER TO MAINTAIN
THE CURRENT TREND IN THE FORECAST. PARTLY CLOUDY WITH A SLIGHT
CHANCE OF DAYTIME THUNDERSTORMS. TEMPERATURES WILL RUN JUST ON THE
WARM SIDE OF NORMAL...BY UP TO A COUPLE OF DEGREES AT TIMES.
MODERATE EAST AND SE WINDS WILL GRADUALLY DIMINISH...ALLOWING SEA
BREEZE CIRCULATIONS FOR THE WEEKEND AFTERNOONS.
&&
.AVIATION...
VFR CONDITIONS WILL PREVAIL ACROSS THE REGION THROUGH TONIGHT.
AREAS OF BKN CIGS 040-050 ACROSS WEST CENTRAL AND SOUTHWEST
FLORIDA...WITH A FEW SHOWERS CREATING MVFR CIGS/VSBYS IN THE FMY/RSW
AREA. DECREASING CLOUDINESS TONIGHT WITH SKIES GENERALLY BECOMING
PARTLY CLOUDY ACROSS THE ENTIRE AREA.
&&
.MARINE...
THE PRESSURE GRADIENT WILL REMAIN TIGHT OVER THE FORECAST WATERS
THROUGH WEDNESDAY BETWEEN HIGH PRESSURE TO OUR NORTH...AND A
WESTWARD MOVING AREA OF LOW PRESSURE ACROSS THE SOUTHEAST GULF OF
MEXICO. ADVISORY LEVEL WINDS OVER THE SOUTHERN THIRD OF THE MARINE
AREA WILL EXPAND NORTHWARD THIS EVENING TO INCLUDE THE MIDDLE MARINE
LEGS. THE GRADIENT IS ANTICIPATED TO RELAX DURING THE LATER PORTION
OF THE WEEK ALLOWING WINDS AND SEAS TO SUBSIDE.
&&
.FIRE WEATHER...
EASTERLY FLOW BETWEEN HIGH PRESSURE TO OUR NORTH AND AN AREA OF LOW
PRESSURE OVER THE SOUTHEAST GULF OF MEXICO WILL CONTINUE TO SUPPLY
THE REGION WITH ABUNDANT LOW LEVEL MOISTURE THROUGH AT LEAST
WEDNESDAY. RELATIVE HUMIDITY IS EXPECTED TO REMAIN GENERALLY ABOVE
CRITICAL LEVELS THE NEXT SEVERAL DAYS...AND NO SIGNIFICANT FIRE
WEATHER CONCERNS ARE FORECAST.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 70 89 70 85 / 10 15 10 30
FMY 69 83 69 85 / 25 50 20 40
GIF 66 89 67 87 / 10 10 10 15
SRQ 69 86 70 84 / 15 25 15 40
BKV 65 90 65 86 / 10 10 10 20
SPG 72 84 71 82 / 10 20 10 35
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...LAKE WIND ADVISORY UNTIL 7 PM EDT THIS EVENING FOR
CHARLOTTE-DE SOTO-HARDEE-HIGHLANDS-HILLSBOROUGH-LEE-
MANATEE-PINELLAS-POLK-SARASOTA.
GULF WATERS...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 11 AM EDT
TUESDAY FOR ENGLEWOOD TO TARPON SPRINGS OUT 20 NM-
ENGLEWOOD TO TARPON SPRINGS OUT 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 11 AM EDT TUESDAY FOR BONITA
BEACH TO ENGLEWOOD OUT 20 NM-BONITA BEACH TO
ENGLEWOOD OUT 20 TO 60 NM.
&&
$$
SYNOPSIS/SHORT TERM/MARINE...MROCZKA
AVIATION/FIRE WEATHER...OGLESBY
LONG TERM...RUDE
AREA FORECAST DISCUSSION
NWS MIAMI FL
158 PM EDT MON APR 30 2012
.AVIATION...
REGIONAL OBSERVATIONS INDICATE A SURFACE LOW ACROSS THE FLORIDA
STRAITS TO THE SOUTHWEST OF KEY WEST THAT HAS ENHANCED THE LOCAL
PRESSURE GRADIENT SIGNIFICANTLY WITH EASTERLY FLOW NEAR 20 KNOTS
TO GUSTS TO NEAR 30 KNOTS FOR THE EAST COAST TAF SITES EXPECTED TO
CONTINUE THROUGH 00Z TUESDAY AND COULD REMAIN AT THAT STRENGTH INTO
TUESDAY MORNING. THE LOW PRESSURE SYSTEM WILL MAINTAIN DEEP
TROPICAL MOISTURE ACROSS THE REGION THROUGH THIS EVENING AND WILL
LIKELY CONTINUE INTO TUESDAY MORNING...MAINTAINING VCSH ALL EAST
COAST TAF SITES THROUGH THE FORECAST PERIOD WITH BRIEF PERIODS OF
IFR CONDITIONS POSSIBLE WITH THE HEAVIEST SHOWERS THIS AFTERNOON
AND INTO AT LEAST 00Z TUESDAY.
60
&&
.PREV DISCUSSION... /ISSUED 945 AM EDT MON APR 30 2012/
UPDATE...
MODERATE TO HEAVY RAIN SHOWERS CONTINUE TO PUSH WEST ACROSS THE
ATLANTIC WATERS AND SOUTH FLORIDA PENINSULA. LATEST RADAR TRENDS
DO SHOW SOME ENHANCEMENT OF HEAVIER RAIN SHOWERS WITH GUSTY WINDS
AND BRIEF HEAVY DOWNPOURS. LATEST LAPS DATA SHOW 50-55 KT 700 MB
WINDS STREAMING ACROSS PALM BEACH COUNTY. HOWEVER...THE 10Z HRRR
ANALYSIS...WHICH HAS PERFORMED WELL LATELY...SHOWS MOST OF THE
SHOWER AND THUNDERSTORM ACTIVITY GETTING SHUNTED SOUTH AND WEST
AROUND THE KEYS ALONG WITH THE MOVEMENT OF THE TROUGH. ONGOING
FORECAST PARAMETERS LOOK GOOD SO NO UPDATES ARE PLANNED ATTM.
PREV DISCUSSION... /ISSUED 649 AM EDT MON APR 30 2012/
AVIATION...12Z ISSUANCE...A SURFACE TROUGH JUST OFF THE
SOUTHEAST FLORIDA COAST WILL PUSH SLOWLY WEST TODAY WHILE A MID
LEVEL LOW ALSO RETROGRADES ACROSS THE REGION. SCATTERED TO
NUMEROUS SHOWERS AND PERHAPS A FEW TSRA EXPECTED, ESPECIALLY FROM
KFXE AND POINTS SOUTH AND WEST. VCSH ARE WARRANTED FOR ALL SITES
THROUGH THE DAY, WITH TEMPO GROUPS ASSIGNED FOR RA AND MVFR
CEILINGS/VISIBILITIES. SOME HEAVIER ACTIVITY MAY ALSO RESULT IN
BRIEF IFR CONDITIONS. SURFACE WINDS WILL ALSO BE A CONCERN WITH
SUSTAINED SPEEDS AROUND 20 KNOTS AND FREQUENT HIGHER GUSTS.
PREV DISCUSSION... /ISSUED 357 AM EDT MON APR 30 2012/
DISCUSSION...
WATER VAPOR IMAGERY FROM EARLY THIS MORNING SHOWED DRY AIR HAD
WRAPPED INTO THE MID/UPPER LOW LOCATED OVER SOUTH FLORIDA. THIS HAS
PREVENTED THE HEAVY RAIN THAT WAS EXPECTED ACROSS THE REGION
OVERNIGHT...AND INSTEAD LIGHT TO MODERATE SHOWERS WERE MOVING ACROSS
SOUTH FLORIDA. MOST MODEL GUIDANCE HAS BEEN EXTREMELY
INCONSISTENT...FLIPPING BACK AND FORTH EVEN IN THE VERY SHORT TERM.
COMPLETELY TOSSED OUT THE 00Z GFS AS IT IS SUFFERING FROM CONVECTIVE
FEEDBACK. IT HAS A BLOWUP NEAR NAPLES IN THE NEXT COUPLE
HOURS...WHICH STEALS ALL THE MOISTURE FROM THE ATLANTIC.
THE HRRR SHOWS THE AREA OF HEAVIER RAIN THAT WAS DEVELOPING TO THE
EAST SOUTHEAST OF THE KEYS POSSIBLY MOVING NORTHWARD INTO MIAMI DADE
COUNTY OVER THE NEXT SEVERAL HOURS AND THEN MOVING TO THE WEST AND
OUT OF THE REGION AN HOUR OR TWO AFTER SUNRISE. THE MODEL SHOWS THAT
IS PRETTY MUCH THE ENTIRE BALL GAME...WITH EVERYTHING BASICALLY
DISSIPATING AFTER THAT AND ONLY LIGHT TO MODERATE RAIN THROUGHOUT
THE DAY. THIS SCENARIO IS DEFINITELY POSSIBLE...MUCH LIKE WHAT
HAPPENED YESTERDAY. HOWEVER...IN THEORY...WITH THE UPPER LOW
RETROGRADING TO THE WEST AND THE INVERTED TROUGH MOVING TO THE
WEST ACROSS THE REGION...THE CHANCES FOR HEAVIER RAIN SHOULD
ACTUALLY BE BETTER TODAY THAN YESTERDAY. THE ECMWF FOLLOWS THIS
SCENARIO...WITH HEAVIER RAIN MOVING INTO THE COASTLINE BETWEEN 12
AND 18Z AND THEN CONTINUING THROUGH MUCH OF THE DAY. SO ANOTHER
1-3 INCHES OF RAIN IS EXPECTED ALONG THE COAST TODAY...WITH
LOCALLY HIGHER AMOUNTS. THOUGHT ABOUT DROPPING THE FLOOD WATCH
FOR PALM BEACH COUNTY AS MOST OF THE HEAVY RAIN SHOULD BE ACROSS
BROWARD AND MIAMI DADE COUNTY. HOWEVER...SINCE GUIDANCE HAS BEEN
INCONSISTENT AT BEST AND THE SOUTHEAST PORTION OF PALM BEACH
COUNTY COULD RECEIVE HEAVY RAIN...LEFT THE FLOOD WATCH IN PLACE.
BREEZY TO WINDY CONDITIONS ARE EXPECTED TODAY...ESPECIALLY TOWARDS
THE EAST COAST...WITH WINDS GUSTING TO 25-35 MPH THROUGH THE DAY. IF
THERE ARE ANY HEAVIER SHOWERS OR THUNDERSTORMS...WIND GUSTS UP TO 50
MPH WILL BE POSSIBLE. UNDERCUT GUIDANCE FOR HIGH TEMPERATURES TODAY
BY 2 TO 8 DEGREES ACROSS THE REGION...CUTTING TEMPS THE MOST ACROSS
THE GULF COAST. GUIDANCE TEMPS IN THE LOW TO MID 80S SEEMED
UNREASONABLE FOR NAPLES DUE TO THE CLOUD COVER AND RAINFALL
EXPECTED TODAY...AND TEMPERATURES MAY ACTUALLY NOT RISE OUT OF THE
LOWER 70S. ACROSS MOST OF THE REGION...TEMPERATURES MORE THAN
LIKELY WILL NOT CHANGE BY MORE THAN A COUPLE DEGREES FROM WHAT
WILL BE OBSERVED THIS MORNING.
THE SHARP INVERTED TROUGH IS EXPECTED TO MOVE WELL OUT INTO THE GULF
OVERNIGHT TONIGHT...BUT ONSHORE FLOW AND A STREAM OF DEEP MOISTURE
WILL STAY OVER THE REGION AS HIGH PRESSURE HOLDS STEADY OVER THE
WESTERN ATLANTIC. WITH A RELATIVELY TIGHT GRADIENT
REMAINING...SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED ALONG THE
EAST COAST AND DEEP SOUTH FLORIDA. HIGH PRESSURE IS EXPECTED TO
REMAIN OVER THE WESTERN ATLANTIC THROUGH MIDWEEK...WITH AROUND 20
KNOT WINDS CONTINUING OVER THE LOCAL ATLANTIC WATERS. SO AT LEAST
SCATTERED SHOWERS WILL CONTINUE...ESPECIALLY IN THE OVERNIGHT
HOURS DUE TO THE SPEED SHEAR ALONG THE COAST. HIGH PRESSURE IS
EXPECTED TO WEAKEN THURSDAY INTO THE WEEKEND...AND RAIN CHANCES
ARE EXPECTED TO SLOWLY DECREASE THROUGH THIS PERIOD. AS THE RAIN
CHANCES DECREASE...TEMPERATURES WILL WARM BACK INTO THE 80S TO
AROUND 90 ACROSS THE NORTHWEST INTERIOR.
AVIATION...
06Z ISSUANCE...A SURFACE TROUGH OF LOW PRESSURE CONTINUES TO MOVE
SLOWLY WEST NEAR THE SOUTHEAST FLORIDA COAST. MEANWHILE, THE
ASSOCIATED MID LEVEL LOW IS LOCATED OVER FAR SOUTH FLORIDA. WITH
PERSISTENT AND STRONG EASTERLY FLOW CONTINUING, WE EXPECT
SCATTERED TO NUMEROUS SHOWERS TO PREVAIL, ALONG WITH PERHAPS A FEW
TSRA AS WELL. TEMPO GROUPS TO INDICATE MVFR CEILINGS ARE
WARRANTED, ALTHOUGH EVEN IFR CONDITIONS COULD BRIEFLY OCCUR IN
HEAVIER SHRA. EASTERLY WINDS WILL PERSIST THROUGH THE TAF PERIOD.
SUSTAINED SURFACE WINDS WILL AVERAGE 15-20 KNOTS WITH FREQUENT
HIGHER GUSTS.
MARINE...
DETERIORATING MARINE CONDITIONS WILL CONTINUE THROUGH
EARLY IN THE WEEK WITH SCA FOR ATLANTIC AND GULF WATERS. SEAS IN
THE GULF STREAM WILL LIKELY BE UP TO 8 FEET THROUGH LATE TUESDAY
BEFORE SUBSIDING BY THE MIDDLE OF THE WEEK AS THE GRADIENT WEAKENS.
FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE IN PLACE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 78 73 81 74 / 60 30 30 20
FORT LAUDERDALE 76 73 79 74 / 70 50 40 40
MIAMI 76 73 79 74 / 70 60 50 40
NAPLES 77 70 81 70 / 50 30 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR COASTAL BROWARD-
COASTAL MIAMI DADE-COASTAL PALM BEACH-FAR SOUTH MIAMI DADE-
INLAND MIAMI DADE-METRO BROWARD-METRO MIAMI DADE-METRO PALM
BEACH.
HIGH RIP CURRENT RISK THROUGH TUESDAY EVENING FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM DEERFIELD BEACH TO OCEAN REEF, FL OUT 20 NM-COASTAL
WATERS FROM JUPITER INLET TO DEERFIELD BEACH, FL OUT 20 NM-
WATERS FROM DEERFIELD BEACH TO OCEAN REEF, FL EXTENDING
FROM 20 NM TO THE TERRITORIAL WATERS OF THE BAHAMAS-WATERS
FROM JUPITER INLET TO DEERFIELD BEACH, FL EXTENDING FROM 20
NM TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR BISCAYNE BAY.
GM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT TUESDAY FOR COASTAL WATERS
FROM CHOKOLOSKEE TO BONITA BEACH, FL OUT 20 NM-COASTAL
WATERS FROM EAST CAPE SABLE TO CHOKOLOSKEE, FL OUT 20 NM-
GULF WATERS FROM CHOKOLOSKEE TO BONITA BEACH, FL EXTENDING
FROM 20 TO 60 NM.
&&
$$
DISCUSSION/MARINE/FIRE...10/CD
AVIATION/RADAR...60/BD
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
125 PM EDT MON APR 30 2012
.Forecast Update...
Issued at 1256 PM EDT Mon Apr 30 2012
Temperatures have warmed to around 80 across the region, which has
allowed a nice cumulus field to develop. A recent AMDAR sounding
still indicates a strong inversion at around 6 kft, which is roughly
where tops are on area clouds. As more moisture pushes into the
region from the west, still expect this inversion to weaken and
allow for showers and thunderstorms to develop by late afternoon.
The latest HRRR seems overly aggressive in bringing in precip
earlier this afternoon, especially given that cap in place. Think
this moisture will be what helps to break the cap for later
activity. The latest Rapid Refresh looks more reasonable, having
that first band push east and die in the mid afternoon and then the
next line coming in this evening. This version is also in line with
the latest SPC WRF, which brings a line of storms through at least
the northern 2/3rds of the region in the 23 to 03Z time frame.
As for severity of these storms, still think damaging wind is the
main threat, with hail and heavy rainfall as secondary ones. Think
amount of moisture available will keep the atmosphere warm enough to
prevent the golfball to baseball-sized hail we`ve had out of the
last couple of events.
Issued at 1000 AM EDT Mon Apr 30 2012
Delayed onset of higher pops a little later in the day based on
current conditions and high-res model forecasts. At the same time,
raised the pop upper limit for this afternoon over the northwest
forecast area to low-end likely by 23Z and then continued into the
evening hours across my northern row of Indiana counties. Higher
precipitable water air is moving into the region from the west
southwest. SREF indicates anomalies 2 standard deviations above
normal for this time of year. The reason for the delay in timing is
a mid-level cap, indicated by model soundings as well as an earlier
AMDAR sounding between 8 and 12 kft. NAM model soundings indicate
this cap weakening by 21Z over the northwest as the moisture moves
in.
Given this moisture, wet bulb zeroes are much higher than the last
couple of events, thus think any hail that forms likely will be
below severe limits. Winds aloft are stronger though. Have a 30-kt
low-level jet at 925 mb by late afternoon, which should cause some
gusty winds this afternoon as heating mixes some of that wind down.
Think gusty winds and heavy rain will be the main threats from
today`s storms, as 0-6 km shear will be 40-50 kts and because of
that high pw air mentioned above.
For highs today, made a little more of a gradient between mid 80s
over the south and east and including the Louisville metro and lower
80s over the northwest, where cloud cover should limit insolation.
Issued at 624 AM EDT Mon Apr 30 2012
Latest IR satellite imagery showing a more extensive area of
mid-high level cloud debris streaming in from the west. Will be
making a quick update to increase sky cover a bit this morning.
We`re a little concerned that this extensive mid-high level cloud
cover may hamper temperatures today. For now, have backed off
temperatures slightly with this forecast update. Should clouds
remain plentiful throughout the day, further decreases in afternoon
highs may be required in subsequent forecast updates. Rest of the
forecast elements look good at the moment.
.Short Term (Today through Tuesday)...
Issued at 333 AM EDT Mon Apr 30 2012
Early morning satellite imagery reveals partly cloudy skies across
southern Indiana and central Kentucky. A diffuse warm front has
gradually lifted northward through the region this morning. Based
on the latest surface observations, it appears to generally be north
of the I-64 corridor at this time. For the remainder of the early
morning hours, expect very little change in the weather with partly
cloudy skies expected. Temperatures are expected to fall into the
upper 50s to the lower 60s over the next few hours. A few showers
may develop later this morning, but feel that the best chances will
generally be north of our forecast area across central IL/IN/OH.
For Today, the multi-model consensus suggests that the warm front
will continue to push northward and away from our area. This will
place southern Indiana and central Kentucky solidly into the warm
sector. Increasing southwesterly flow will lead to breezy
conditions later this morning and into afternoon hours while
temperatures soar into the lower to middle 80s. Some upper 80s will
be possible across the far south...mainly south of the
Cumberland/Nunn Parkway. Model proximity soundings suggest that
we`ll see a well mixed atmosphere this afternoon that should remain
largely capped. The cap looks to be stronger across the south and
southeast sections and slightly weaker across the north/northeast.
A few isolated to widely scattered showers/thunderstorms may develop
later this afternoon during peak heating. The NSSL WRF and SPC WRF
are suggestive of this, but both models really hold back
precipitation chances to the west during the afternoon hours along a
cold front and an approaching mid-level wave. For now, plan on
keeping things mostly dry through the afternoon but will keep in a
slight-low chc PoP threat in the north/northwest for late this
afternoon.
By tonight, approaching cold front and associated mid-level wave are
expected to transverse the region. With plenty of moisture and
instability in place, we expected a line of convection to develop to
the west and push into the region this evening. Coverage and timing
still are a bit difficult to pin down, but it appears that several
lines of broken convection are likely to transverse the region.
Fairly decent 50-60kt mid-level flow along with the
moisture/instability will be plenty for strong/severe convection to
fire this evening. Right now, the thermal/wind profiles would be
more suggestive of damaging winds and large hail being the primary
threats with any thunderstorm activity. Highest chances of
convection look to be across southern Indiana and the northern half
of Kentucky as the amount of capping in southern KY may result in
much more isolated-scattered convection. Temperatures are not going
to fall all that much tonight with readings only cooling into the
lower-middle 60s.
For Tuesday, surface cold front is likely to stall out across the
forecast area as quasi-zonal mid-level flow pattern looks to make
things difficult for the boundary to make any headway southward.
Several mid-level perturbations will cross the region resulting in
period of convection moving across the region throughout the day.
Individual timing/placement details are still somewhat murky at this
point, but it appears that a fairly decent chance of rain appears in
the offing for this time frame. Abundant cloud cover and associated
precipitation will keep temperatures down a few degrees. Highs
generally look to warm into the upper 70s to the lower 80s.
.Long Term (Tuesday Night through Sunday)...
Issued at 310 AM EDT Apr 30 2012
An unstable mostly zonal flow will continue through mid week.
Although ridging will strengthen over the southeast CONUS Wed, Tues
night into Wed morning we could still see some showers/t-storms with
the last of the embedded upper level waves in zonal flow. Any
remaining boundaries from convection on Tues may also provide added
focus for overnight convection.
By Wed afternoon, though, looks like ridging and a good cap will
become established over the area allowing for dry conditions.
Ridging will stay in place through Thurs with temps soaring into the
mid 80s both Wed/Thurs. MOS guidance actually brings high temps
into the upper 80s to around 90 for Wed/Thurs, however, went
with mid 80s do to the lack of a strong anomalous ridge signal in
the ensembles and due to antecedent wet conditions with lush green
vegetation which may limit day time heating some what.
By Thurs night, the upper ridge will begin to retrograde back west
allowing our northeast back into the unstable flow aloft along the
periphery of the ridge. Long range models are in decent agreement
with the break down of the eastern side of this ridge through
Saturday. However, evolution of the ridge becomes a bit fuzzy for
the beginning of next week. With this in mind, feel pretty
confident with 20-40% POPs in for Thurs night through Saturday.
However, not as confident with low POPs for Sun/Mon time frame.
Temperatures should remain well above normal through early next week
in the low to mid 80s for highs. 60s for lows.
&&
.Aviation (18Z TAF Issuance)...
Updated at 125 PM EDT Mon Apr 30 2012
Warm frontal boundary continues to push slowly northward across the
Cold frontal boundary to the west will head eastward late this
afternoon and evening bringing a chance of showers and storms to the
terminals late this afternoon...and more likely this evening. Have
tried to time the best chance for stronger storms moving through the
terminals based on the rapid refresh and SPC WRF models. This
forecast probably will have to be fine tuned as these storms
organize. The rest of the forecast will keep in chances for storms
has a frontal boundary gets stalled over the region and as moisture
increases in the atmosphere to well above normal for this time of
year.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Updates..........MJ/RJS
Short Term.......MJ
Long Term........AMS
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1256 PM EDT MON APR 30 2012
.Forecast Update...
Issued at 1256 PM EDT Mon Apr 30 2012
Temperatures have warmed to around 80 across the region, which has
allowed a nice cumulus field to develop. A recent AMDAR sounding
still indicates a strong inversion at around 6 kft, which is roughly
where tops are on area clouds. As more moisture pushes into the
region from the west, still expect this inversion to weaken and
allow for showers and thunderstorms to develop by late afternoon.
The latest HRRR seems overly aggressive in bringing in precip
earlier this afternoon, especially given that cap in place. Think
this moisture will be what helps to break the cap for later
activity. The latest Rapid Refresh looks more reasonable, having
that first band push east and die in the mid afternoon and then the
next line coming in this evening. This version is also in line with
the latest SPC WRF, which brings a line of storms through at least
the northern 2/3rds of the region in the 23 to 03Z time frame.
As for severity of these storms, still think damaging wind is the
main threat, with hail and heavy rainfall as secondary ones. Think
amount of moisture available will keep the atmosphere warm enough to
prevent the golfball to baseball-sized hail we`ve had out of the
last couple of events.
Issued at 1000 AM EDT Mon Apr 30 2012
Delayed onset of higher pops a little later in the day based on
current conditions and high-res model forecasts. At the same time,
raised the pop upper limit for this afternoon over the northwest
forecast area to low-end likely by 23Z and then continued into the
evening hours across my northern row of Indiana counties. Higher
precipitable water air is moving into the region from the west
southwest. SREF indicates anomalies 2 standard deviations above
normal for this time of year. The reason for the delay in timing is
a mid-level cap, indicated by model soundings as well as an earlier
AMDAR sounding between 8 and 12 kft. NAM model soundings indicate
this cap weakening by 21Z over the northwest as the moisture moves
in.
Given this moisture, wet bulb zeroes are much higher than the last
couple of events, thus think any hail that forms likely will be
below severe limits. Winds aloft are stronger though. Have a 30-kt
low-level jet at 925 mb by late afternoon, which should cause some
gusty winds this afternoon as heating mixes some of that wind down.
Think gusty winds and heavy rain will be the main threats from
today`s storms, as 0-6 km shear will be 40-50 kts and because of
that high pw air mentioned above.
For highs today, made a little more of a gradient between mid 80s
over the south and east and including the Louisville metro and lower
80s over the northwest, where cloud cover should limit insolation.
Issued at 624 AM EDT Mon Apr 30 2012
Latest IR satellite imagery showing a more extensive area of
mid-high level cloud debris streaming in from the west. Will be
making a quick update to increase sky cover a bit this morning.
We`re a little concerned that this extensive mid-high level cloud
cover may hamper temperatures today. For now, have backed off
temperatures slightly with this forecast update. Should clouds
remain plentiful throughout the day, further decreases in afternoon
highs may be required in subsequent forecast updates. Rest of the
forecast elements look good at the moment.
.Short Term (Today through Tuesday)...
Issued at 333 AM EDT Mon Apr 30 2012
Early morning satellite imagery reveals partly cloudy skies across
southern Indiana and central Kentucky. A diffuse warm front has
gradually lifted northward through the region this morning. Based
on the latest surface observations, it appears to generally be north
of the I-64 corridor at this time. For the remainder of the early
morning hours, expect very little change in the weather with partly
cloudy skies expected. Temperatures are expected to fall into the
upper 50s to the lower 60s over the next few hours. A few showers
may develop later this morning, but feel that the best chances will
generally be north of our forecast area across central IL/IN/OH.
For Today, the multi-model consensus suggests that the warm front
will continue to push northward and away from our area. This will
place southern Indiana and central Kentucky solidly into the warm
sector. Increasing southwesterly flow will lead to breezy
conditions later this morning and into afternoon hours while
temperatures soar into the lower to middle 80s. Some upper 80s will
be possible across the far south...mainly south of the
Cumberland/Nunn Parkway. Model proximity soundings suggest that
we`ll see a well mixed atmosphere this afternoon that should remain
largely capped. The cap looks to be stronger across the south and
southeast sections and slightly weaker across the north/northeast.
A few isolated to widely scattered showers/thunderstorms may develop
later this afternoon during peak heating. The NSSL WRF and SPC WRF
are suggestive of this, but both models really hold back
precipitation chances to the west during the afternoon hours along a
cold front and an approaching mid-level wave. For now, plan on
keeping things mostly dry through the afternoon but will keep in a
slight-low chc PoP threat in the north/northwest for late this
afternoon.
By tonight, approaching cold front and associated mid-level wave are
expected to transverse the region. With plenty of moisture and
instability in place, we expected a line of convection to develop to
the west and push into the region this evening. Coverage and timing
still are a bit difficult to pin down, but it appears that several
lines of broken convection are likely to transverse the region.
Fairly decent 50-60kt mid-level flow along with the
moisture/instability will be plenty for strong/severe convection to
fire this evening. Right now, the thermal/wind profiles would be
more suggestive of damaging winds and large hail being the primary
threats with any thunderstorm activity. Highest chances of
convection look to be across southern Indiana and the northern half
of Kentucky as the amount of capping in southern KY may result in
much more isolated-scattered convection. Temperatures are not going
to fall all that much tonight with readings only cooling into the
lower-middle 60s.
For Tuesday, surface cold front is likely to stall out across the
forecast area as quasi-zonal mid-level flow pattern looks to make
things difficult for the boundary to make any headway southward.
Several mid-level perturbations will cross the region resulting in
period of convection moving across the region throughout the day.
Individual timing/placement details are still somewhat murky at this
point, but it appears that a fairly decent chance of rain appears in
the offing for this time frame. Abundant cloud cover and associated
precipitation will keep temperatures down a few degrees. Highs
generally look to warm into the upper 70s to the lower 80s.
.Long Term (Tuesday Night through Sunday)...
Issued at 310 AM EDT Apr 30 2012
An unstable mostly zonal flow will continue through mid week.
Although ridging will strengthen over the southeast CONUS Wed, Tues
night into Wed morning we could still see some showers/t-storms with
the last of the embedded upper level waves in zonal flow. Any
remaining boundaries from convection on Tues may also provide added
focus for overnight convection.
By Wed afternoon, though, looks like ridging and a good cap will
become established over the area allowing for dry conditions.
Ridging will stay in place through Thurs with temps soaring into the
mid 80s both Wed/Thurs. MOS guidance actually brings high temps
into the upper 80s to around 90 for Wed/Thurs, however, went
with mid 80s do to the lack of a strong anomalous ridge signal in
the ensembles and due to antecedent wet conditions with lush green
vegetation which may limit day time heating some what.
By Thurs night, the upper ridge will begin to retrograde back west
allowing our northeast back into the unstable flow aloft along the
periphery of the ridge. Long range models are in decent agreement
with the break down of the eastern side of this ridge through
Saturday. However, evolution of the ridge becomes a bit fuzzy for
the beginning of next week. With this in mind, feel pretty
confident with 20-40% POPs in for Thurs night through Saturday.
However, not as confident with low POPs for Sun/Mon time frame.
Temperatures should remain well above normal through early next week
in the low to mid 80s for highs. 60s for lows.
&&
.Aviation (12Z TAF Issuance)...
Updated at 655 AM EDT Mon Apr 30 2012
Warm frontal boundary continues to push slowly northward across the
region this morning. Surface winds are generally out of the
southeast and will gradually shift to the south and then southwest
later on this morning. Fair amount of mid-high level cloud debris
continues to spread across the region. This will result in a high
cloud ceiling this morning, but not have an impact on aviation
activities.
Cold frontal boundary to the west will head eastward late this
afternoon and evening bringing a chance of showers and storms to the
terminal late this afternoon...and more likely this evening.
Current forecast still looks in good shape with keeping VCTS in the
forecast for the terminals mainly after 30/22Z. Once convection
develops later this afternoon/eve...probably will be better able to
time convection and areal coverage in later forecasts.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Updates..........MJ/RJS
Short Term.......MJ
Long Term........AMS
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
422 PM EDT MON APR 30 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, COMING EAST FROM ILLINOIS, WILL BRING
SHOWERS AND THUNDERSTORMS TONIGHT INTO TUESDAY MORNING. A
LINGERING WARM FRONT WILL MAINTAIN WARM CONDITIONS AND A CHANCE OF
SHOWERS AT TIMES INTO THE WEEKEND.
&&
.NEAR TERM /THROUGH TUESDAY/...
BLEND OF RECENT RADAR DATA AND HRRR MODEL OUTPUT SHOW A BAND OF
NUMEROUS SHOWERS AND THUNDERSTORMS, ASSOCIATED WITH CONVERGENCE
JUST AHEAD OF A LOW PRESSURE SYSTEM COMING EAST FROM ILLINOIS,
WILL PASS THROUGH THE UPPER OHIO VALLEY TONIGHT, MAINLY BETWEEN 8 PM
AN 2 PM.
SPC HAS OUTLOOKED A SLIGHT RISK OF SEVERE THUNDERSTORMS
DUE TO THIS BAND WITH THE MAIN THREAT BEING DAMAGING WIND AND
LARGE HAIL. RECENT SREF MODEL ASSESSMENT OF INSTABILITY AND
VERTICAL WIND SHEAR, SHOW THERE IS THE POTENTIAL FOR SEVERE THIS
EVENING. HOWEVER, IT APPEARS INSTABILITY, SHEAR AND HENCE SEVERE
POTENTIAL WILL BE DECREASING AS THE THUNDERSTORM COMPLEX PASSES EAST
OF THE OHIO-PENNSYLVANIA LINE AFTER 10 PM.
RECENT SREF MODEL OUTPUT CONTINUES TO SHOW SHOWER PROSPECTS WILL
DECREASE DAYTIME TUESDAY AS THE LOW PRESSURE CENTER EXITS EAST
PAST THE APPALACHIAN MOUNTAINS. WOULD HAVE MADE MENTION OF EARLY
MORNING POST-RAIN FOG, BUT SURFACE WINDS MAY BE FAST ENOUGH TO
PREVENT LOW VISIBILITIES, BUT INSTEAD CAUSE STRATUS CLOUDS.
RECENT SREF MODEL OUTPUT THEN SHOWS A WEST-EAST ORIENTED FRONTAL
BOUNDARY LINGERING NEAR THE MASON DIXON LINE TUESDAY AFTERNOON.
EXPECT SURFACE LAYER MOISTURE TO SLOWLY INCREASE, AND THUS MAINTAIN
A SMALL CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS MUCH
OF THE UPPER OHIO VALLEY.
BLEND OF RECENT GFS AND NAM MOS AND HRRR MODEL OUTPUT MAINTAIN A
FORECAST OF LOW TEMPERATURES TONIGHT TO BE MORE THAN 10 DEGREES
WARMER THAN NORMAL, AND HIGHS TUESDAY TO BE 5 TO 10 DEGREES WARMER
THAN NORMAL.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
BLEND OF RECENT SREF AND ECMWF MODEL OUTPUT CONTINUES TO SHOW
UNCERTAINTY IN THE MEANDERINGS OF THE WARM FRONT ACROSS THE UPPER
OHIO VALLEY. SO HAVE OPTED TO MAINTAIN A CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF THE UPPER OHIO VALLEY FOR MOST OF
THIS PERIOD.
EXPECT TEMPERATURES TO CONTINUE MUCH WARMER THAN NORMAL, PER
RECENT GFS, NAM, AND ECMWF MOS AND SREF MODEL OUTPUT, WITH HIGHS
ABOVE 80 ACROSS LOWER ELEVATIONS SOUTH, AND LOWS IN THE 50S TO
LOWER 60S.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
WARM FRONT WILL PUSH TO THE NORTH LATE WEDNESDAY AND EARLY
THURSDAY ALLOWING THE AREA TO ENTER BACK INTO THE WARM SECTOR. RIDGE
CONTINUES TO BUILD IN THE EAST...SO AS TEMPS RISE RAIN CHANCES
WILL DECREASE. DEWPOINTS WILL REMAIN IN THE 60S THROUGH THIS WHOLE
PERIOD.
RIDGE STARTS TO BREAK DOWN FRIDAY ALLOWING SFC COLD FRONT TO MOVE
TOWARD THE AREA. BUT THE FRONT WILL STALL OVER THE AREA THROUGH
THE WEEKEND WITH CHANCES FOR SHOWERS/THUNDERSTORMS.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
EASTBOUND LOW PRESSURE WILL BRING A BAND OF SHOWERS AND SCATTERED
THUNDERSTORMS, STARTING ABOUT 01Z IN THE KZZV AREA AND 03Z IN THE
KPIT AREA. CONTINUE TO LEAVE MENTION OF THUNDER OUT OF THE TAFS
DUE TO THE RESTRICTED COVERAGE OF THE STORMS. HAVE INTRODUCED A
PERIOD OF LATE-NIGHT IFR STRATUS DUE TO SURFACE LAYER CONDENSATION
OF POST-RAIN EVAPORATION. HAVE MORE CONFIDENCE THAT IFR CEILINGS
WILL DEVELOP THAN IFR VISIBILITIES IN FOG DUE TO MIXING ASSOCIATED
WITH SURFACE WINDS 7-10 KTS.
EXPECT CONTINUED VERTICAL MIXING TO HELP CEILINGS LIFT TO MVFR LEVELS
LATE MORNING AND VFR TUESDAY AFTERNOON.
SURFACE WINDS WILL GO FROM SOUTH EARLY THIS EVENING TO SOUTHWEST
AND WEST LATE TONIGHT AND DAYTIME TUESDAY. SPEEDS WILL BE MAINLY
6-10 KTS. ITS POSSIBLE THUNDERSTORMS TOWARD MIDNIGHT CAN GENERATE
GUSTS OVER 25 KTS, BUT HAVE TOO LOW CONFIDENCE IN THUNDERSTORM
COVERAGE OR INTENSITY TO INCLUDE IN TAF FORECAST.
.OUTLOOK...TUESDAY NIGHT THROUGH SATURDAY...
RESTRICTIONS WILL REMAIN POSSIBLE IN SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH THE PERIOD.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
134 PM EDT MON APR 30 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM, COMING EAST FROM ILLINOIS, WILL BRING
SCATTERED SHOWERS AND THUNDERSTORMS LATE THIS AFTERNOON WITH MORE
NUMEROUS SHOWERS AND THUNDERSTORMS TONIGHT INTO TUESDAY MORNING.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PER BLEND OF RECENT RADAR AND SURFACE DATA, PLUS RECENT HRRR AND
NAM MODEL OUTPUT, EXPECT A WARM FRONTAL BAND OF SCATTERED SHOWERS
AND THUNDERSTORMS TO PASS THROUGH WESTERN PENNSYLVANIA, MAINLY NORTH
OF PITTSBURGH THIS AFTERNOON. AS SURFACE DEW POINTS INCREASE, THE
COVERAGE OF SHOWERY PRECIPITATION CAN ALSO INCREASE.
HAVE ADJUSTED TEMPERATURES UP 1 OR 2 DEGREES FOR THE AFTERNOON,
PARTICULARLY SOUTH OF THE MAIN SHOWER BAND, ALTHOUGH HIGHS FOR
LOWER ELEVATIONS SOUTH CAN BE UP TO 15 DEGREES WARMER THAN
NORTHERN AND MOUNTAIN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
PER RECENT NAM MODEL OUTPUT, EXPECT COVERAGE OF SHOWERS AND
THUNDERSTORMS TO INCREASE TO NUMEROUS TONIGHT DUE TO INCREASED
CONVERGENCE AND LIFT ASSOCIATED WITH THE INCOMING EASTBOUND LOW
PRESSURE CENTER FROM ILLINOIS. WITH SURFACE MOISTURE ALSO
INCREASED, EXPECT INCREASED INSTABILITY.
SPC HAS OUTLOOKED MUCH OF THE AREA FOR A SLIGHT RISK OF SEVERE
THUNDERSTORMS WITH HAIL AND WIND THE TWIN THREAT.
MOST MEMBERS OF RECENT SREF MODEL OUTPUT, INCLUDING THE
OPERATIONAL NAM MODEL, SHOW THAT MOST POST-SYSTEM SHOWERS WILL
HAVE EXITED EAST PAST THE MOUNTAINS BY MIDDAY TUESDAY. HOWEVER, A
LINGERING FRONTAL BOUNDARY NEAR THE MASON-DIXON LINE MAY MAINTAIN
A CHANCE OF SHOWERS AND POSSIBLE THUNDERSTORMS FOR THAT AREA INTO
THE AFTERNOON.
BY TUESDAY NIGHT, THAT FRONTAL BOUNDARY WILL BEGIN TO MOVE NORTHWARD
AGAIN AS DEEPENING SFC LOW OVER THE NORTHERN PLAINS INCREASES
SOUTHERLY WINDS ACROSS THE OHIO VALLEY.
UPPER LEVEL HEIGHTS WILL BEGIN TO RISE LATE TUESDAY NIGHT AND
WEDNESDAY MORNING. SO THE FRONT WILL MOVE THROUGH, BUT WITH
RIDGING ALOFT NOT QUITE SURE HOW MUCH SHOWER ACTIVITY WILL
DEVELOP. FOR NOW, THE BEST WAY TO HANDLE THIS WILL BE WITH LOW
CHANCE PRECIPITATION PROBABILITIES FOR WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
WARM FRONT WILL PUSH TO THE NORTH LATE WEDNESDAY AND EARLY
THURSDAY ALLOWING THE AREA TO ENTER BACK INTO THE WARM SECTOR. RIDGE
CONTINUES TO BUILD IN THE EAST...SO AS TEMPS RISE RAIN CHANCES
WILL DECREASE. DEWPOINTS WILL REMAIN IN THE 60S THROUGH THIS WHOLE
PERIOD.
RIDGE STARTS TO BREAK DOWN FRIDAY ALLOWING SFC COLD FRONT TO MOVE
TOWARD THE AREA. BUT THE FRONT WILL STALL OVER THE AREA THROUGH
THE WEEKEND WITH CHANCES FOR SHOWERS/THUNDERTORMS.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
WARM ADVECTION AND INCREASING LOW LEVEL MOISTURE TODAY AND TONIGHT.
ONLY ISOLATED SHOWERS THIS AFTERNOON IN THE HEATING OF THE DAY.
LOW PRESSURE ASSOCIATED WITH THE UPPER LEVEL SHORT WAVE WILL
APPROACH AREA THIS EVENING BRINGING AN INCREASING RISK OF SHOWERS
AND ISOLATED THUNDERSTORMS. ABOUT 01Z IN THE KZZV AREA AND 03Z IN
THE KPIT AREA. CONTINUE TO LEAVE MENTION OF THUNDER OUT OF THE
TAFS DUE TO THE ISOLATED NATURE OF THE STORMS.
.OUTLOOK...TUESDAY THROUGH SATURDAY...
RESTRICTIONS IN SCT SHRA AND TSRA ARE POSSIBLE INTO WEDNESDAY AS
GREAT LAKES LOW PRESSURE ADVECTS WARMTH AND MOISTURE ACROSS THE
REGION. MORE TSRA ARE ANTICIPATED FOR THURSDAY THROUGH SATURDAY
IN ASSOCIATION WITH THE SYSTEMS CDFNT APPROACH. FLIGHT CONDITIONS
WILL BE GENERALLY VFR THROUGH THE EXTENDED PERIOD WITH
RESTRICTIONS ONLY WITH SCATTERED STORMS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1251 PM CDT MON APR 30 2012
.AVIATION... /18Z TAF ISSUANCE/
STRATUS BREAKING UP ACROSS THE REGION BUT NEGATIVE CU RULE
INDICATING BKN CEILINGS THIS AFTERNOON A LITTLE ABOVE AND BELOW
030. LATEST GUIDANCE SHOWING A SMALL THREAT FOR SHOWERS DURING
THE LATE AFTERNOON AND EARLY EVENING HOURS FOR KSTC...KMSP AND
KRNH AS AN UPPER TROUGH MOVES THROUGH. OVERNIGHT...A WARM FRONT
WILL APPROACH FROM THE CENTRAL PLAINS. SCATTERED SHOWERS AND A FEW
THUNDERSTORMS ARE POSSIBLE FOR THE MN TAF SITES AFTER 06Z THROUGH
DAYBREAK. CONFIDENCE IS HIGHEST FOR THUNDER AT KAXN. THE WARM
FRONT WILL MOVE ACROSS THE TAF SITES ON TUESDAY. SOUTH WINDS WILL
INCREASE TO 15 TO 20 KNOTS DURING THE MORNING AND EARLY AFTERNOON
HOURS ALONG WITH GUSTS REACHING 25 TO 30 KNOTS. THUNDERSTORM
CHANCES INCREASING TUESDAY AFTERNOON AND EVENING AS A COLD FRONT
PUSHES SLOWLY ACROSS THE MN TAF SITES. SOME SEVERE STORMS ARE
POSSIBLE.
KMSP...CEILING IMPROVING THIS AFTERNOON TO BKN030-035. SMALL
THREAT FOR SHOWERS DURING THE LATE AFTERNOON HOURS BUT CONFIDENCE
IS NOT HIGH. KEPT MENTION TO VCSH. ANOTHER CHANCE FOR SHOWERS AND
ISOLATED THUNDERSTORMS ARRIVES LATE IN THE NIGHT THROUGH DAYBREAK
TUESDAY. SOME THREAT TUESDAY MORNING (12Z-18Z) FOR MVFR CEILINGS
AS LOW LEVEL MOISTURE INCREASES DRAMATICALLY AS A WARM MOVES IN.
SOUTH WINDS NEAR 20 KNOTS LIKELY TUESDAY AFTERNOON ALONG WITH
GUSTS NEAR 30 KNOTS. THUNDERSTORMS CHANCES ON THE RISE LATE
TUESDAY AFTERNOON AND EVENING. A SEVERE STORM IS POSSIBLE.
OUTLOOK...
TUESDAY NIGHT...MVFR-IFR WITH TSRA LIKELY.
WEDNESDAY...VFR/MVFR WITH -TSRA POSSIBLE.
THURSDAY...VFR/MVFR WITH -TSRA POSSIBLE.
&&
.DISCUSSION... /ISSUED 346 AM CDT MON APR 30 2012/
IT APPEARS TO BE SHAPING UP TO BE A BUSY WEEK WEATHERWISE... WITH
CHANCES FOR PCPN SOMEWHERE OVER THE CWFA NEARLY EVERY DAY... AND
THE POTENTIAL FOR SEVERE WEATHER LATE TUESDAY AFTERNOON INTO
TUESDAY NIGHT. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR
ANALYSES SHOW THE PESKY UPPER LOW WHICH WAS OVER THE PLAINS THE
PAST SEVERAL DAYS HAS FINALLY LIFTED NORTHEAST INTO CENTRAL
CANADA. UPPER PV ANALYSIS SHOWS A FILAMENT EXTENDING SOUTH FROM
THIS INTO CENTRAL MINNESOTA AT THE CURRENT TIME... HELPING TO KEEP
A FEW SHRA GOING OVER THE NORTH CENTRAL PORTION OF THE STATE. A
SECOND PV FEATURE IS APPARENT NEAR THE SOUTHEAST MINNESOTA/WEST
CENTRAL WISCONSIN BORDER. THIS COMPACT ANOMALY IS ALSO LIFTING
NORTHEAST... HELPING TO TAKE ITS ASSOCIATED AREA OF SHRA ALONG
WITH IT. THE NEXT UPPER LEVEL FEATURE OF CONSEQUENCE IS A
SHORTWAVE APPARENT OFF THE PACIFIC NORTHWEST COAST. THIS SYSTEM
WILL WORK ACROSS THE NORTHWEST CONUS AND NORTHERN ROCKIES OVER THE
NEXT 24-36 HOURS... THEN PUSH INTO THE NORTHERN PLAINS TUESDAY
AFTERNOON AND EVENING... HELPING TO SET THE STAGE FOR
THUNDERSTORMS AND POSSIBLE SEVERE WEATHER OVER OUR AREA LATE
TUESDAY AFTERNOON AND TUESDAY NIGHT. THE UPPER RIDGE CURRENTLY IN
PLACE OVER THE SOUTHEAST CONUS LOOKS TO STUBBORNLY REMAIN IN PLACE
THROUGH THE WEEK... WHICH WILL HELP TO MAINTAIN SOUTHWEST UPPER
FLOW OVER THE NORTH CENTRAL US. THIS MEANS THE SYSTEM MOVING INTO
THE AREA TUESDAY NIGHT WILL HAVE A TOUGH TIME DISPLACING THE
BAROCLINIC ZONE SOUTHEAST OF OUR AREA... LEAVING AN UNSETTLED
SECOND HALF OF THE WEEK AS MOISTURE AND INSTABILITY LOITER NEARBY
AND A FEW ADDITIONAL SHORTWAVES RIPPLE NORTHEAST FROM THE CENTRAL
ROCKIES AND THROUGH THE NORTHERN PLAINS. THE MODELS ARE ACTUALLY
IN QUITE GOOD AGREEMENT ON THE OVERALL LARGE SCALE PATTERN THROUGH
THE WEEK. HOWEVER... THERE IS A FAIR DEGREE OF SPREAD IN THEIR
TIMING OF INDIVIDUAL SHORTWAVE FEATURES... THE EXACT POSITION OF
THE MAIN BAROCLINIC ZONE THROUGH THE WEEK... AND THE INTERPLAY OF
THESE FEATURES WITH CONVECTIVE DEVELOPMENT. STUCK CLOSE TO A BLEND
OF THE NAM AND GFS THROUGH TUESDAY... THEN HAD A TOUGH TIME
PUTTING MUCH FAITH IN THE SPECIFIC DETAILS OF ANY PARTICULAR
SOLUTION OR COMBINATION OF SOLUTIONS AFTER THAT POINT. THE MAIN
IDEA IS THAT AFTER TUESDAY WE WILL HAVE THE BAROCLINIC ZONE HANG
UP EITHER OVER THE SOUTHERN PORTION OF OUR AREA OR JUST TO THE
SOUTH... WHICH WILL BE CLOSE ENOUGH FOR PERIODIC PCPN CHANCES
THROUGH THE BALANCE OF THE WEEK AS SHORTWAVES OCCASIONALLY MIGRATE
THROUGH THE REGION WITH BOUNDARY LAYER BASED AND/OR ELEVATED
INSTABILITY REMAINING IN PLACE.
FOR TODAY... ABUNDANT LOW CLOUDS AND SOME PATCHY FOG WILL BE IN
PLACE TO START THE DAY... BUT WITH MID-HIGH CLOUDS PRIMARILY SOUTH
OF THE AREA INSOLATION SHOULD WORK TO ERODE THINGS THROUGH THE
MORNING HOURS. BY AFTERNOON WE SHOULD START TO SEE SOME BETTER
RETURN FLOW SETUP... WHICH SHOULD FURTHER ASSIST IN INCREASING
SUNSHINE ACROSS THE AREA. A SECONDARY PV ANOMALY ROTATING AROUND
THE UPPER LOW TO OUR NORTH... CURRENTLY SEEN OVER SOUTHERN
SASKATCHEWAN... WILL SLIDE BY TO OUR NORTH THIS AFTERNOON...
POSSIBLY BRINGING A FEW SHRA TO THE NORTH CENTRAL AND NORTHEAST
PORTION OF THE AREA. WOULDN/T BE SHOCKED IF A SHRA MADE IT AS FAR
SOUTH AS THE TWIN CITIES METRO LATER THIS AFTERNOON AS THIS
FEATURE MOVES BY TO OUR NORTH... BUT FOR NOW STUCK CLOSER TO THE
MODEL CONSENSUS OF KEEPING PCPN NORTH OF THAT AREA. RETURN FLOW
WILL INCREASE MARKEDLY OVER THE WESTERN HALF OF THE AREA
TONIGHT... WITH SUFFICIENT MOISTURE ADVECTION FOR PERHAPS SOME
SHRA/TSRA TO GET GOING OVERNIGHT ACROSS WEST CENTRAL MINNESOTA.
THE BEST FOCUS OF MOISTURE AND FORCING ALONG THE ELEVATED WARM
FRONTAL BOUNDARY LOOKS TO BE NORTH OF OUR AREA LATE TONIGHT INTO
TUESDAY MORNING... BUT SOME ACTIVITY COULD CERTAINLY EXTEND BACK
INTO WEST CENTRAL AND CENTRAL MINNESOTA.
TUESDAY WILL BRING EVEN WARMER TEMPERATURES INTO THE AREA AS WE
FIND OURSELVES IN THE WARM SECTOR AHEAD OF A FRONTAL BOUNDARY
EXTENDING FROM LOW PRESSURE IN SOUTHWEST MANITOBA BACK INTO
CENTRAL NEBRASKA. EXPECT TO SEE SHRA/TSRA DEVELOP JUST WEST OF OUR
AREA TUESDAY AFTERNOON... WITH PERHAPS SOME ADDITIONAL STORMS
DEVELOPING OVER OUR AREA OUT AHEAD OF WHAT SHOULD EVENTUALLY
EVOLVE INTO A BROKEN LINE OF STORMS MOVING FROM THE EASTERN
DAKOTAS INTO WESTERN MINNESOTA DURING THE LATE AFTERNOON AND EARLY
EVENING. THE BEST UPPER FORCING ASSOCIATED WITH THE SHORTWAVE
CURRENTLY OFF THE PACIFIC NORTHWEST COAST WON/T WORK INTO THE AREA
UNTIL LATER TUESDAY EVENING AND INTO THE OVERNIGHT HOURS.
HOWEVER... THERE APPEARS TO BE MORE THAN SUFFICIENT LOW LEVEL
CONVERGENCE AND FRONTOGENETICAL FORCING TO GET STORMS GOING IN AN
ENVIRONMENT WHICH SHOULD SEE MLCAPE VALUES AOA 1500 J/KG AND 0-6KM
BULK SHEAR AOA 40KT. WHEN THE BETTER LARGE SCALE FORCING WORKS
INTO THE REGION LATER IN THE EVENING AND DURING THE OVERNIGHT...
IT WILL LIKELY SERVE TO KEEP THE ACTIVITY GOING AS IT MOVES ACROSS
THE REMAINDER OF MINNESOTA AND INTO WESTERN WISCONSIN. AS THINGS
MIGRATE EAST DURING THE EVENING WOULD EXPECT TO SEE ACTIVITY
EVOLVE INTO A LINEAR SYSTEM... WITH PERHAPS SOME EMBEDDED BOWS
GIVEN 0-2KM BULK SHEAR AOA 25KT ORIENTED PERPENDICULAR TO AN
ANTICIPATED NORTH-SOUTH LINEAR SYSTEM. PRIMARY SEVERE THREATS
SHOULD BE DAMAGING WINDS AND LARGE HAIL FROM LATE TUESDAY
AFTERNOON THROUGH AT LEAST 06Z THAT NIGHT... ALTHOUGH A FEW
TORNADOES CANNOT BE RULED OUT WITH DISCRETE SUPERCELLS WHICH MAY
OCCUR EARLY-ON AS WELL AS EMBEDDED SUPERCELL
STRUCTURES/MESOVORTICES WITH A POTENTIAL LINEAR SYSTEM LATER IN
THE EVENING. THERE REMAINS A FAIR DEGREE OF SPREAD IN THE MODEL
DETAILS WITH RESPECT TO SHEAR PROFILES... PARTICULARLY SUB-2KM
SHEAR BOTH IN TERMS OF SPEED AND DIRECTIONAL COMPONENTS. NEEDLESS
TO SAY... THINGS WILL NEED TO BE MONITORED OVER THE NEXT 24 HOURS
AS THINGS COME INTO BETTER FOCUS AND ADDITIONAL INFORMATION
BECOMES AVAILABLE FROM CONVECTION ALLOWING MODELS. AT THIS
POINT... THE INITIAL CONVECTIVE DEVELOPMENT NEAR THE
DAKOTAS/MINNESOTA BORDER IS OCCURRING RIGHT AT THE END OF THE HIGH
RESOLUTION WINDOW RUNS... ALTHOUGH IT SHOULD BE NOTED THAT BOTH
THE NMM AND ARW SHOW A FEW INDIVIDUAL STORMS QUICKLY ACQUIRING
UPDRAFT HELICITY VALUES AOA 40 M2/S2 BETWEEN 22Z AND 00Z. IN
ADDITION... THE 03Z SREF TORNADO INGREDIENT PROBABILITIES
HIGHLIGHT AN AREA NEAR AND WEST OF THE I-35 CORRIDOR AROUND
00-03Z... SUGGESTING THERE MAY BE A WINDOW OF TIME WHEN CONDITIONS
WILL BE FAVORABLE FOR TORNADIC STORMS.
THE REMAINDER OF THE FORECAST IS QUITE MUDDY... FIGURATIVELY AND
PERHAPS LITERALLY... AFTER TUESDAY NIGHT/S SYSTEM MOVES THROUGH
THE AREA. WITH THE UPPER RIDGE REMAINING IN PLACE IN THE SOUTHEAST
CONUS... HEIGHTS FALL LITTLE ACROSS THE NORTH CENTRAL PART OF THE
COUNTRY... AND THEREFORE THE FRONTAL BOUNDARY WHICH PUSHES INTO
THE AREA TUESDAY NIGHT WILL LINGER NEARBY FOR SEVERAL DAYS.
SHOWERS AND THUNDERSTORM CHANCES LOOK GOOD FROM WEDNESDAY INTO THE
WEEKEND. THE SOUTHERN PORTION OF THE AREA... CLOSER TO THE OLD
FRONTAL BOUNDARY... COULD SEE A SIGNIFICANT AMOUNT OF PCPN OVER
THAT PERIOD OF TIME DEPENDING UPON HOW INDIVIDUAL SHORTWAVES MOVE
THROUGH THE REGION AND WHERE CONVECTION SETS UP AND TRACKS. IT
WILL DEFINITELY NOT BE RAINING THE ENTIRE TIME PERIOD... BUT EACH
DAY LOOKS TO HAVE SOME CHANCE FOR SHRA/TSRA. HOPEFULLY THE
FORECAST CAN BE REFINED TO BETTER IDENTIFY DRY/WET PERIODS AS THE
WEEK PROGRESSES.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/TRH
AREA FORECAST DISCUSSION
NWS BUFFALO NY
359 PM EDT MON APR 30 2012
.SYNOPSIS...
A WARM FRONT WILL LIFT ACROSS NEW YORK FROM THE OHIO VALLEY THIS EVENING
WITH SOME SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO. A COLD
FRONT WILL CROSS THE REGION TONIGHT WITH ANOTHER ROUND OF SHOWERS.
CONDITIONS WILL THEN BECOME NOTABLY WARMER BUT UNSETTLED ACROSS
THE REGION TUESDAY THROUGH THE REMAINDER OF THE WEEK AS
TEMPERATURES WILL CLIMB WELL ABOVE NORMAL.
&&
.NEAR TERM /THROUGH TUESDAY/...
ACTIVE WEATHER FOR THE NEAR TERM AS A SURFACE LOW CENTERED NEAR
SOUTHWESTERN MICHIGAN WILL SHIFT NORTHEAST ACROSS THE LOWER LAKES
TONIGHT THEN OFF THE NEW ENGLAND COAST TUESDAY. A WARM FRONT IS
LIFTING ACROSS NEW YORK THIS AFTERNOON WITH ASSOCIATED RAIN SHOWERS
MOVING FROM WESTERN NEW YORK INTO CENTRAL NEW YORK. A COLD FRONT
EXTENDS SOUTH FROM THE LOW CENTER ACROSS INDIANA. TEMPERATURES IN
THE RAIN-COOLED AIR EAST OF LAKE ERIE ARE IN THE 50S WHILE FURTHER
WEST ACROSS THE OHIO VALLEY UPPER 70S AND LOW 80S ARE OBSERVED AHEAD
OF THE COLD FRONT. TIMING OF THIS LOW WILL KEEP NEW YORK FREE FROM THE
SEVERE WEATHER THAT IS EXPECTED ACROSS THE OH VALLEY TONIGHT.
VISIBLE SATELLITE IMAGERY THIS AFTERNOON IS SHOWING OVERCAST
CLOUDINESS ACROSS MUCH OF NEW YORK AHEAD OF THE WARM FRONT.
REGIONAL RADARS ARE HIGHLIGHTING SHOWERS AND SOME ISOLATED
THUNDERSTORMS ALONG THE WARM AND COLD FRONTAL BOUNDARIES.
HIGHS THIS AFTERNOON WILL LIKELY REMAIN IN THE 50S AS THE WARM
FRONTAL SHOWERS MOVED INTO THE AREA BEFORE MAX HEATING. THROUGH THE
REST OF THE AFTERNOON EXPECT SHOWERS TO CONTINUE TO LIFT NORTH AND
EAST ACROSS CENTRAL AND NORTHERN NY WITH DRYING OCCURRING ACROSS
WESTERN NY BEHIND THE WARM FRONT.
TONIGHT...TEMPERATURES WILL REMAIN MILD WITH WARMER AIR SHIFTING
ACROSS THE REGION WITHIN THE LOW PRESSURE SYSTEMS WARM SECTOR. TEMPS
WILL NOT FALL MUCH OVERNIGHT AND MAY IN FACT REMAIN STEADY OR RISE.
A MIX OF MOS GUIDANCE GIVES NUMBERS IN THE UPPER 40S TO AROUND 50.
SKIES WILL REMAIN MOSTLY CLOUDY. THE COLD FRONT WILL THEN SLIDE
ACROSS EAST ACROSS THE FORECAST AREA. WHILE THE HEAVIEST RAIN AND
POSSIBLE SEVERE STORMS WILL REMAIN SOUTH OF THE FORECAST AREA ACROSS
THE OHIO VALLEY AS INDICATED BY LATEST RUNS OF THE HRRR MODEL...HAVE
INCLUDED LIKELY SHOWERS WITH ISOLATED THUNDER FOR THE OVERNIGHT
PERIOD.
TUESDAY...FRONT MAY STILL BE PRESSING EAST ACROSS CENTRAL AND
NORTHERN NEW YORK TUESDAY MORNING WITH CHANCES FOR SHOWERS. ALL
AREAS SHOULD BE DRY BY THE AFTERNOON WITH A WEAK HIGH PRESSURE
BUILDING IN BEHIND THE FRONT. MOST AREAS WILL TURN OUT PARTLY TO
MOSTLY SUNNY BY AFTERNOON. HIGHS LOOK TO REACH INTO THE LOW 60S
ESPECIALLY ACROSS WESTERN NEW YORK WHERE THE SUN WILL BREAK OUT
EARLIER THAN CENTRAL AND NORTHERN NY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
WE WILL SEE A QUIET START TO THE PERIOD AS WESTERN AND CENTRAL NEW
YORK WILL BE FALLING UNDER THE INFLUENCE OF A BROAD UPPER LEVEL
RIDGE UPSTREAM. SUBSIDENCE OVER THE REGION SHOULD ALLOW FOR MOSTLY
CLEAR SKIES. THIS COMBINED WITH LIGHT WINDS SHOULD ALLOW FOR
TEMPERATURES TO DROP INTO THE UPPER 40S WITH MID 40S IN THE USUAL
COOL SPOTS OF THE SOUTHERN/TIER AND NORTH COUNTRY.
WEDNESDAY WILL FEATURE THE BEGINNING OF THE PRONOUNCED WARM-UP THAT
WILL BE AFFECTING THE REGION THROUGH THE REST OF THE WEEK. THE BROAD
UPPER LEVEL RIDGE WILL SETTLE OVER THE EASTERN UNITED STATES WHILE
RETURN FLOW AROUND A STRONG SURFACE HIGH ANCHORED OFF THE SOUTHEAST
U.S. COAST WILL PUMP INCREASINGLY WARM AND MOIST AIR NORTHWARDS
ACROSS THE OHIO VALLEY AND INTO THE GREAT LAKES REGION. THIS WILL
RESULT IN TEMPERATURES THAT WILL RISE WELL INTO THE 70S WEDNESDAY
AND THURSDAY WITH SOME AREAS POSSIBLY BREACHING 80 ON THURSDAY. IN
ADDITION TO THE WARMTH...IT WILL START TO FEEL MUGGY AS WELL AS
SURFACE DEWPOINTS WILL ALSO RISE INTO 50S WEDNESDAY AND POSSIBLY LOW
60S THURSDAY AS THE RICH GULF MOISTURE SURGES NORTHWARDS.
WITH THE WARM AND MOIST AIR ADVECTING NORTH INTO THE REGION...WE
INTRODUCE THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS. THE GREATEST
POTENTIAL FOR CONVECTION ON WEDNESDAY WILL BE FOUND ACROSS
FAR WESTERN NEW YORK DURING LATE AFTERNOON AS THE LEADING EDGE OF A
THETA-E RIDGE SLIDES INTO THE NIAGARA FRONTIER. THE THREAT FOR
CONVECTION CONTINUES INTO WEDNESDAY NIGHT AS MODELS INDICATE ML CAPE
VALUES OF AROUND 400 J/KG WEST OF THE GENESEE VALLEY.
CONDITIONS THURSDAY SHOULD BE RIPE FOR SHOWERS AND THUNDERSTORMS AS
WE WILL REMAIN IN A VERY MOIST AIRMASS...HOWEVER WITH LIGHT FLOW AND
A LACK OF A CLEAR TRIGGER SUCH AS A SHORTWAVE...AM NOT EXPECTING
ORGANIZED OR SEVERE CONVECTION. HOWEVER MAY SEE WIDESPREAD
LAKE-BREEZE INDUCED SHOWERS/THUNDERSTORMS...PARTICULARLY INT HE
AFTERNOON/EVENING HOURS. THE FLY IN THE OINTMENT MAY BE WEAK
MID-LEVEL LAPSE RATES THAT MAY PUT A LID ON CONVECTION FROM BREAKING
OUT.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
EXPECT MUCH OF THE SAME ON FRIDAY AS THE VERY WARM/MOIST AND
UNSTABLE AIRMASS LINGERS OVER THE REGION WITH HIGHS IN THE 70S AND
AT LEAST A CHANCE OF SHOWERS AND THUNDERSTORMS. THE FORECAST BECOMES
MURKIER BY THE WEEKEND WITH THE MODELS AT ODDS OVER THE
LOCATION/TIMING OF A COLD FRONT SWEEPING SOUTH OUT OF CANADA. THE
GFS PUSHES THE FRONT ACROSS THE FORECAST AREA SATURDAY...A PROSPECT
THAT WOULD RESULT IN A MUCH COOLER/DRIER WEEKEND THAN CURRENTLY
FORECAST. THE ECMWF...ON THE OTHER HAND...PUSHES A MUCH WEAKER
FRONT ACROSS THE REGION LATE ON SUNDAY. GIVEN THESE
DIFFERENCES...WILL OPT FOR A FORECAST THAT LEANS MORE TOWARDS THE
ECMWF/PERSISTENCE WITH HIGHS IN THE LOW 70S...LOWS IN THE 50S...AND
CHANCE POPS.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL REMAIN IN PLACE THROUGH THIS AFTERNOON THEN
LOWERING TO MVFR/IFR OVERNIGHT. A WARM FRONT IS LIFTING ACROSS NEW
YORK STATE FROM THE OHIO VALLEY THIS AFTERNOON WITH SOME LIGHT
SHOWERS SCATTERED ACROSS THE STATE. LOW PRESSURE WILL SHIFT EAST
OVERNIGHT FROM MICHIGAN ACROSS LAKE ONTARIO WITH A WEAK COLD FRONT.
ANOTHER ROUND OF SHOWERS WITH ISOLATED LIGHTNING IS POSSIBLE
OVERNIGHT WITH THE COLD FRONT. MOST STRONG CONVECTION WILL BE
LIMITED TO OH/PA BUT KJHW WILL NEED TO BE WATCH AS STORMS FIRE THIS
AFTERNOON ACROSS OH/IN. THERE WILL ALSO BE A MARGINAL RISK OF LOW
LEVEL WIND SHEAR TONIGHT OVER WESTERN NEW YORK...AS SOUTHEAST SFC
WINDS OF 10 KTS OR LESS WILL BE ACCOMPANIED BY SOUTHERLY WINDS OF
35-40KTS AT 1000-1500 FT AHEAD OF THE FRONT. LAMP GUIDANCE INDICATES
CIGS LIFTING BY THE END OF THE FORECAST PERIOD.
OUTLOOK...
TUESDAY...IFR/MVFR EARLY THEN VFR.
WEDNESDAY THROUGH FRIDAY...VFR/MVFR IN SHOWERS.
&&
.MARINE...
WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
DURING THIS PERIOD...ALTHOUGH MORE ACTIVE WEATHER CAN BE EXPECTED.
A WARM FRONT IS LIFTING ACROSS THE LOWER GREAT LAKES FROM THE OHIO VALLEY
TODAY. THIS WILL PRODUCE GENTLE TO OCCASIONALLY MODERATE EASTERLIES
ON LAKES ERIE AND ONTARIO...THEN AS THE WARM FRONT AND ITS SHOWERS
MOVE THROUGH THIS AFTERNOON AND EVENING WINDS WILL BECOME MORE
SOUTHEASTERLY. OVERNIGHT A SURFACE LOW WILL SHIFT EAST ACROSS LAKE ONTARIO
WITH WINDS SHIFTING TO SOUTHWEST BY TUESDAY MORNING. EXPECT LIGHT
WINDS AND NEGLIGIBLE WAVES THROUGH TUESDAY NIGHT.
&&
.CLIMATE...
THIS CHILLY SUNDAY MORNING SAW BUFFALO SET A NEW RECORD LOW
TEMPERATURE WITH THE 28 DEGREE READING BREAKING THE OLD RECORD OF
29. THIS IS THE FIRST TIME A RECORD LOW MINIMUM TEMPERATURE HAS
BEEN SET AT THE BUFFALO AIRPORT SINCE MARCH 6 2007.
ROCHESTER NEW YORK ALSO TIED A RECORD LOW THIS MORNING...THE 27
DEGREES TIED THE RECORD LOW VALUE. THIS IS THE FIRST TIME A RECORD
LOW MINIMUM WAS EITHER SET OR TIED AT ROCHESTER SINCE JULY 14 2009.
BUFFALO AND ROCHESTER WILL ALSO HAVE POTENTIAL FOR THEIR FIRST BELOW
NORMAL TEMPERATURE MONTH SINCE MARCH 2011. BOTH BUFFALO AND
ROCHESTER WITH HELP OF THE LAST 10 DAYS OF APRIL BELOW NORMAL MAY
JUST END FINISHING UP A FEW TENTHS OF A DEGREE BELOW NORMAL FOR
APRIL. FINAL STATISTICS WILL BE CALCULATED AFTER THE MONTH
FINISHES.
APRIL`S MONTHLY TEMPERATURE DEPARTURE IS A DRASTIC DIFFERENCE FROM
MARCH 2012 WHEN BOTH CITIES HAD A SIGNIFICANTLY ABOVE NORMAL
TEMPERATURE DEPARTURE. ONLY ONCE IN RECORDED HISTORY HAS THERE BEEN
A COOLER APRIL THAN MARCH AND THAT OCCURRED FOR BUFFALO BACK IN 1946.
THERE IS GOOD POTENTIAL FOR BOTH CITIES TO HAVE A COOLER APRIL
THAN MARCH IN 2012. THROUGH THE 28TH OF APRIL BUFFALO`S AVERAGE
APRIL TEMPERATURE IS 2.1 DEGREES COOLER THAN THE AVERAGE
TEMPERATURE RECORDED IN MARCH 2012. FOR ROCHESTER...WHICH HAS BEEN
SLIGHTLY WARMER THIS MONTH THROUGH THE SAME TIME SPAN...APRIL 2012
HAS BEEN 1.2 DEGREES COOLER THAN MARCH 2012.
BELOW ARE THE YEARS AND TOP FIVE LOWEST SPREADS BETWEEN APRIL
AVERAGE TEMPERATURE AND MARCH AVERAGE TEMPERATURE.
BUFFALO
YEAR APRIL AVG TEMPERATURE MINUS MARCH AVG TEMPERATURE
1946 -0.1
1898 2.3
1907 2.9
1903 3.0
1920 3.8
ROCHESTER
YEAR APRIL AVG TEMPERATURE MINUS MARCH AVG TEMPERATURE
1898 0.8
1946 1.2
1907 2.8
1903 3.0
1995 3.1
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WOOD
LONG TERM...WOOD
AVIATION...SMITH
MARINE...SMITH/WOOD
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BUFFALO NY
345 PM EDT MON APR 30 2012
.SYNOPSIS...
A WARM FRONT WILL LIFT ACROSS NEW YORK FROM THE OHIO VALLEY THIS EVENING
WITH SOME SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO. A COLD
FRONT WILL CROSS THE REGION TONIGHT WITH ANOTHER ROUND OF SHOWERS.
CONDITIONS WILL THEN BECOME NOTABLY WARMER BUT UNSETTLED ACROSS
THE REGION TUESDAY THROUGH THE REMAINDER OF THE WEEK AS
TEMPERATURES WILL CLIMB WELL ABOVE NORMAL.
&&
.NEAR TERM /THROUGH TUESDAY/...
ACTIVE WEATHER FOR THE NEAR TERM AS A SURFACE LOW CENTERED NEAR
SOUTHWESTERN MICHIGAN WILL SHIFT NORTHEAST ACROSS THE LOWER LAKES
TONIGHT THEN OFF THE NEW ENGLAND COAST TUESDAY. A WARM FRONT IS
LIFTING ACROSS NEW YORK THIS AFTERNOON WITH ASSOCIATED RAIN SHOWERS
MOVING FROM WESTERN NEW YORK INTO CENTRAL NEW YORK. A COLD FRONT
EXTENDS SOUTH FROM THE LOW CENTER ACROSS INDIANA. TEMPERATURES IN
THE RAIN-COOLED AIR EAST OF LAKE ERIE ARE IN THE 50S WHILE FURTHER
WEST ACROSS THE OHIO VALLEY UPPER 70S AND LOW 80S ARE OBSERVED AHEAD
OF THE COLD FRONT. TIMING OF THIS LOW WILL KEEP NEW YORK FREE FROM THE
SEVERE WEATHER THAT IS EXPECTED ACROSS THE OH VALLEY TONIGHT.
VISIBLE SATELLITE IMAGERY THIS AFTERNOON IS SHOWING OVERCAST
CLOUDINESS ACROSS MUCH OF NEW YORK AHEAD OF THE WARM FRONT.
REGIONAL RADARS ARE HIGHLIGHTING SHOWERS AND SOME ISOLATED
THUNDERSTORMS ALONG THE WARM AND COLD FRONTAL BOUNDARIES.
HIGHS THIS AFTERNOON WILL LIKELY REMAIN IN THE 50S AS THE WARM
FRONTAL SHOWERS MOVED INTO THE AREA BEFORE MAX HEATING. THROUGH THE
REST OF THE AFTERNOON EXPECT SHOWERS TO CONTINUE TO LIFT NORTH AND
EAST ACROSS CENTRAL AND NORTHERN NY WITH DRYING OCCURRING ACROSS
WESTERN NY BEHIND THE WARM FRONT.
TONIGHT...TEMPERATURES WILL REMAIN MILD WITH WARMER AIR SHIFTING
ACROSS THE REGION WITHIN THE LOW PRESSURE SYSTEMS WARM SECTOR. TEMPS
WILL NOT FALL MUCH OVERNIGHT AND MAY IN FACT REMAIN STEADY OR RISE.
A MIX OF MOS GUIDANCE GIVES NUMBERS IN THE UPPER 40S TO AROUND 50.
SKIES WILL REMAIN MOSTLY CLOUDY. THE COLD FRONT WILL THEN SLIDE
ACROSS EAST ACROSS THE FORECAST AREA. WHILE THE HEAVIEST RAIN AND
POSSIBLE SEVERE STORMS WILL REMAIN SOUTH OF THE FORECAST AREA ACROSS
THE OHIO VALLEY AS INDICATED BY LATEST RUNS OF THE HRRR MODEL...HAVE
INCLUDED LIKELY SHOWERS WITH ISOLATED THUNDER FOR THE OVERNIGHT
PERIOD.
TUESDAY...FRONT MAY STILL BE PRESSING EAST ACROSS CENTRAL AND
NORTHERN NEW YORK TUESDAY MORNING WITH CHANCES FOR SHOWERS. ALL
AREAS SHOULD BE DRY BY THE AFTERNOON WITH A WEAK HIGH PRESSURE
BUILDING IN BEHIND THE FRONT. MOST AREAS WILL TURN OUT PARTLY TO
MOSTLY SUNNY BY AFTERNOON. HIGHS LOOK TO REACH INTO THE LOW 60S
ESPECIALLY ACROSS WESTERN NEW YORK WHERE THE SUN WILL BREAK OUT
EARLIER THAN CENTRAL AND NORTHERN NY.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
SURFACE LOW AND NEARLY FLAT UPPER TROUGH WILL MOVE INTO EASTERN NEW
YORK TUESDAY...ANY REMAINING SHOWERS WILL END FROM WEST TO EAST
DURING THE MORNING ACROSS WESTERN NY AND BY EARLY AFTERNOON FOR
CENTRAL AND NORTHERN NY. INCREASING SUNSHINE DURING THE AFTERNOON
WILL ALLOW TEMPERATURES TO WARM WELL INTO THE 60S...ALTHOUGH
READINGS WILL BE SLIGHTLY COOLER CLOSE TO THE LAKES DUE TO THE
WESTERLY FLOW IN THE WAKE OF THE DEPARTING TROUGH.
A WEAK RIDGE WILL BUILD ACROSS NEW YORK STATE TUESDAY NIGHT AND
BRING MAINLY DRY CONDITIONS. THE CLEAR SKIES AND LIGHT WINDS WILL
ALLOW THE OVERNIGHT TEMPS TO SETTLE TO THE LOWER TO MIDDLE 40S.
A RESURGENCE OF WARM AND INCREASINGLY MOIST AIR AHEAD OF ANOTHER
WARM FRONT WILL BRING A CHANCE FOR SHOWERS AND SCATTERED
THUNDERSTORMS WEDNESDAY AND WEDNESDAY NIGHT. 850MB TEMPS OF +15C AND
30-35KT WINDS WILL BRING AN INCREASE IN BOUNDARY LAYER INSTABILITY
WITH AN ELEVATED CAPE AROUND 500 J/KG...MORE EVIDENT DURING THE
LATER PORTION OF THE DAY AND INTO THE EVENING.
HIGH TEMPS ON WEDNESDAY WILL RANGE FROM THE UPPER 60S/LOWER 70S EAST
OF LAKE ONTARIO TO THE MID 70S WEST OF THE FINGER LAKES. MILD
CONDITIONS WILL PREVAIL WEDNESDAY NIGHT WITH TEMPERATURES EXPECTED
TO RANGE THROUGH THE 50S.
WILL MAINTAIN CHANCE POPS FOR THURSDAY AND THURSDAY NIGHT AS THE
WARMTH AND MOISTURE FLOW CONTINUES. THE UPPER RIDGE AXIS SLIPS
SLIGHTLY EAST OF THE REGION AND PRESENTS SOME MINIMAL DIFFLUENCE
ALOFT...AS GFS DEPICTS A SURFACE LOW FORMING ALONG THE FRONTAL
BOUNDARY JUST NORTH OF THE GREAT LAKES. THIS KEEPS OUR REGION IN IN
THE WARM SECTOR AND WILL BRING ANOTHER VERY WARM DAY FOR
THURSDAY...HIGHS IN THE MID 60S TO LOWER 70S EAST OF LAKE ONTARIO
AND LOWER TO MID 70S ELSEWHERE. LOWS THURSDAY NIGHT WILL BE LIKEWISE
MILD WITH MID TO UPPER 50S PREVAILING.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
AN UPPER LEVEL RIDGE THAT WILL BE IN PLACE OVER THE EASTERN THIRD OF
THE NATION AT THE START OF THE PERIOD WILL FLATTEN OUT AND BE
REPLACED BY AN UPPER LEVEL TROUGH THAT WILL BE DIGGING SOUTH ACROSS
QUEBEC AND NEW ENGLAND ON SUNDAY. AS A RESULT...WE WILL SEE A
GRADUAL TRANSITION FROM VERY MILD CONDITIONS ON FRIDAY TO MORE
SEASONABLE TEMPERATURES BY THE END OF THE WEEKEND.
ON FRIDAY...A WEAK COLD FRONT WILL DROP SOUTH ACROSS NEW YORK STATE
LATE IN THE DAY OR TOWARD THE EVENING...AND BRING A CHANCE FOR A FEW
MORE SHOWERS AND POSSIBLE THUNDERSTORMS. TEMPERATURES WILL STILL BE
WELL ABOVE AVERAGE AS THE FRONT WILL ARRIVE AFTER THE PEAK
HEATING...HIGHS SIMILAR TO OR SLIGHTLY WARMER THEN THURSDAY WITH
LOWER TO MID 70S IN THE NORTH COUNTRY AND MID TO UPPER 70S FOR THE
REMAINDER OF THE REGION.
THE GFS AND ECMWF ARE SOMEWHAT OUT OF PHASE REGARDING THE TIMING AND
PLACEMENT OF THE UPPER LEVEL TROUGH THAT IS FORECAST TO DEEPEN OVER
QUEBEC DURING THE WEEKEND. THIS DISCREPANCY ALSO AFFECTS THE TIMING
AND STRENGTH OF THE ASSOCIATED COLD FRONT. GFS IS MORE PROGRESSIVE
WITH THE INFLUX OF COOLER AIR FOLLOWING THE COLD FRONT AND FORCES
THE NOSE OF HIGH PRESSURE FARTHER SOUTH ACROSS LAKE ONTARIO AND MUCH
OF THE FORECAST AREA ON SATURDAY NIGHT...WHEREAS ECMWF DOES NOT
PRESS THE FRONT NOR THE NOSE OF THE HIGH PRESSURE AS FAR TO THE
SOUTH AND LEAVES THE FRONTAL BOUNDARY ACROSS THE REGION THROUGH THE
WEEKEND. WITH THE DIFFERING SOLUTIONS PRESENTED BY GFS AND EC...WILL
OPT TO JUST GO WITH CHANCE POPS FOR SHOWERS BOTH DAYS ALONG WITH
MORE SEASONABLE TEMPERATURES...TRENDING CLOSER TO CLIMATE NORMALS
FOR EARLY MAY.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
VFR CONDITIONS WILL REMAIN IN PLACE THROUGH THIS AFTERNOON THEN
LOWERING TO MVFR/IFR OVERNIGHT. A WARM FRONT IS LIFTING ACROSS NEW
YORK STATE FROM THE OHIO VALLEY THIS AFTERNOON WITH SOME LIGHT
SHOWERS SCATTERED ACROSS THE STATE. LOW PRESSURE WILL SHIFT EAST
OVERNIGHT FROM MICHIGAN ACROSS LAKE ONTARIO WITH A WEAK COLD FRONT.
ANOTHER ROUND OF SHOWERS WITH ISOLATED LIGHTNING IS POSSIBLE
OVERNIGHT WITH THE COLD FRONT. MOST STRONG CONVECTION WILL BE
LIMITED TO OH/PA BUT KJHW WILL NEED TO BE WATCH AS STORMS FIRE THIS
AFTERNOON ACROSS OH/IN. THERE WILL ALSO BE A MARGINAL RISK OF LOW
LEVEL WIND SHEAR TONIGHT OVER WESTERN NEW YORK...AS SOUTHEAST SFC
WINDS OF 10 KTS OR LESS WILL BE ACCOMPANIED BY SOUTHERLY WINDS OF
35-40KTS AT 1000-1500 FT AHEAD OF THE FRONT. LAMP GUIDANCE INDICATES
CIGS LIFTING BY THE END OF THE FORECAST PERIOD.
OUTLOOK...
TUESDAY...IFR/MVFR EARLY THEN VFR.
WEDNESDAY THROUGH FRIDAY...VFR/MVFR IN SHOWERS.
&&
.MARINE...
WINDS AND WAVES WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA
DURING THIS PERIOD...ALTHOUGH MORE ACTIVE WEATHER CAN BE EXPECTED.
A WARM FRONT IS LIFTING ACROSS THE LOWER GREAT LAKES FROM THE OHIO VALLEY
TODAY. THIS WILL PRODUCE GENTLE TO OCCASIONALLY MODERATE EASTERLIES
ON LAKES ERIE AND ONTARIO...THEN AS THE WARM FRONT AND ITS SHOWERS
MOVE THROUGH THIS AFTERNOON AND EVENING WINDS WILL BECOME MORE
SOUTHEASTERLY. OVERNIGHT A SURFACE LOW WILL SHIFT EAST ACROSS LAKE ONTARIO
WITH WINDS SHIFTING TO SOUTHWEST BY TUESDAY MORNING. EXPECT LIGHT
WINDS AND NEGLIGIBLE WAVES THROUGH TUESDAY NIGHT.
&&
.CLIMATE...
THIS CHILLY SUNDAY MORNING SAW BUFFALO SET A NEW RECORD LOW
TEMPERATURE WITH THE 28 DEGREE READING BREAKING THE OLD RECORD OF
29. THIS IS THE FIRST TIME A RECORD LOW MINIMUM TEMPERATURE HAS
BEEN SET AT THE BUFFALO AIRPORT SINCE MARCH 6 2007.
ROCHESTER NEW YORK ALSO TIED A RECORD LOW THIS MORNING...THE 27
DEGREES TIED THE RECORD LOW VALUE. THIS IS THE FIRST TIME A RECORD
LOW MINIMUM WAS EITHER SET OR TIED AT ROCHESTER SINCE JULY 14 2009.
BUFFALO AND ROCHESTER WILL ALSO HAVE POTENTIAL FOR THEIR FIRST BELOW
NORMAL TEMPERATURE MONTH SINCE MARCH 2011. BOTH BUFFALO AND
ROCHESTER WITH HELP OF THE LAST 10 DAYS OF APRIL BELOW NORMAL MAY
JUST END FINISHING UP A FEW TENTHS OF A DEGREE BELOW NORMAL FOR
APRIL. FINAL STATISTICS WILL BE CALCULATED AFTER THE MONTH
FINISHES.
APRIL`S MONTHLY TEMPERATURE DEPARTURE IS A DRASTIC DIFFERENCE FROM
MARCH 2012 WHEN BOTH CITIES HAD A SIGNIFICANTLY ABOVE NORMAL
TEMPERATURE DEPARTURE. ONLY ONCE IN RECORDED HISTORY HAS THERE BEEN
A COOLER APRIL THAN MARCH AND THAT OCCURRED FOR BUFFALO BACK IN 1946.
THERE IS GOOD POTENTIAL FOR BOTH CITIES TO HAVE A COOLER APRIL
THAN MARCH IN 2012. THROUGH THE 28TH OF APRIL BUFFALO`S AVERAGE
APRIL TEMPERATURE IS 2.1 DEGREES COOLER THAN THE AVERAGE
TEMPERATURE RECORDED IN MARCH 2012. FOR ROCHESTER...WHICH HAS BEEN
SLIGHTLY WARMER THIS MONTH THROUGH THE SAME TIME SPAN...APRIL 2012
HAS BEEN 1.2 DEGREES COOLER THAN MARCH 2012.
BELOW ARE THE YEARS AND TOP FIVE LOWEST SPREADS BETWEEN APRIL
AVERAGE TEMPERATURE AND MARCH AVERAGE TEMPERATURE.
BUFFALO
YEAR APRIL AVG TEMPERATURE MINUS MARCH AVG TEMPERATURE
1946 -0.1
1898 2.3
1907 2.9
1903 3.0
1920 3.8
ROCHESTER
YEAR APRIL AVG TEMPERATURE MINUS MARCH AVG TEMPERATURE
1898 0.8
1946 1.2
1907 2.8
1903 3.0
1995 3.1
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...SMITH
NEAR TERM...SMITH
SHORT TERM...WCH
LONG TERM...WCH
AVIATION...SMITH
MARINE...SMITH/WOOD
CLIMATE...THOMAS
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
145 PM EDT MON APR 30 2012
.SYNOPSIS...
AFTER A VERY COLD START...A WARM SOUTHWEST FLOW WILL BRING WARMER
TEMPERATURES TO THE REGION TODAY. MOISTURE WILL ARRIVE AHEAD OF A
FRONTAL SYSTEM THIS EVENING...WITH SCATTERED SHOWERS AND A FEW
THUNDERSTORMS EXPECTED OVERNIGHT. THE FRONT WILL MOVE THROUGH
EARLY TUESDAY...ALLOWING SHOWERS TO CLEAR OUT BY LATE MORNING...YET
CLOUDS MAY LINGER INTO TUESDAY AFTERNOON. A WARM AND UNSETTLED
PATTERN IS EXPECTED WEDNESDAY THROUGH FRIDAY...WITH CHANCES FOR
SHOWERS AND THUNDERSTORMS.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...FORECAST ON TRACK WITH LITTLE TO CHANGE. A QUICK
CHECK OF THE LATEST RUC SOUNDINGS SHOWS THAT WE SHOULD BE ABLE TO
MIX DOWN SOME VERY DRY AIR LATER THIS MORNING INTO THIS AFTERNOON.
LOWERED DEWPOINTS INTO THE TEENS TO LOWER 20S ESPECIALLY IN NEPA
TO ACCOUNT FOR THIS. DESPITE THIS DRY AIR...RELATIVELY LIGHT WINDS
WILL MINIMIZE FIRE WEATHER CONCERNS. THE PREVIOUS AFD IS BELOW...
A WIDESPREAD HARD FREEZE IS OBSERVED THIS MORNING. MANY LOCATIONS
HAVE FALLEN INTO THE LOWER AND MIDDLE 20S, ESPECIALLY IN THE
CENTRAL SOUTHERN TIER VALLEYS AND THE CATSKILLS/EASTERN
SUSQUEHANNA REGION.
MINOR CHANGES THIS MORNING TO REFLECT TEMPERATURE AND DEW POINT
TRENDS. THE MAIN FORECAST IS ON COURSE.
PREVIOUS DISCUSSION...
STRONGLY DECOUPLED LOWER ATMOSPHERE WILL BRING A VERY COLD
MORNING. BUT MUCH WARMER AIR ALOFT WILL WORK ITS WAY DOWN TO THE
SURFACE DURING MID MORNING MIXING HOURS.
MAIN CHANGE WE MADE TO THE NEAR TERM THIS PACKAGE WAS TO SCALE
BACK THE CLOUDS THROUGH MID AFTERNOON. SOUNDINGS LOOK EXTREMELY
DRY, AND THERE IS LITTLE UPSTREAM SAVE FOR THIN CIRRUS. CLOUDS
WILL MOVE IN RAPIDLY DURING THE LATE AFTERNOON, BUT THE MAJORITY
OF THE DAY SHOULD BE MOSTLY SUNNY WITH TEMPS IN THE LOWER 60S.
PRECIP SHOULD ARRIVE NEAR SUNSET IN THE WESTERN FA, THEN SPREAD
EASTWARD OVER THE FOLLOWING 3 HOURS. INSTABILITY ALOFT SUGGESTS
THUNDER POTENTIAL, AND WE HAVE INCREASED THE AREAL AND TEMPORAL
COVERAGE FOR CHC THUNDER. NAM DEPICTS LARGE AREA OF 33+ K-INDICES
FOR A 3-6 HOUR WINDOW LATE TONIGHT.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/...
EMBEDDED WAVE ALOFT FINISHES MOVING THROUGH EARLY
TUESDAY...HELPING SHALLOW SURFACE FRONT TO SETTLE THROUGH MOST OR
ALL OF THE AREA. MOST SHOWER ACTIVITY WILL EXIT WITH THE UPPER
WAVE...BUT SHALLOW MOISTURE WILL BE LEFT HANGING UNDERNEATH
INVERSION WHILE WARM AIR ADVECTION STRENGTHENS ALOFT. THIS WILL
LET CLOUDS LINGER LONGER THAN THE SHOWERS...INTO TUESDAY
AFTERNOON...THOUGH WITH GRADUAL EROSION INTO TUESDAY NIGHT AS
SURFACE FRONT REVERSES DIRECTION AND HEADS NORTH AS A WARM FRONT.
NEAR NORMAL TEMPERATURES TUESDAY...UPON PASSAGE OF THE WARM FRONT
AND CONTINUED HEIGHT RISES FROM BUILDING UPPER RIDGE...WILL TREND
TO 14-18 DEGREES ABOVE NORMAL WEDNESDAY THROUGH FRIDAY.
HOWEVER...OUR REGION APPEARS LIKELY TO STILL BE EMBEDDED WITHIN
SOUTHERN PERIPHERY OF THE WESTERLIES...WITH MULTIPLE WAVES PASSING
THROUGH DURING THE PERIOD. MODELS ARE CONVERGING ON HAVING ONE OF
THESE WAVES PASS THROUGH WITH POTENTIAL FOR NOCTURNAL CONVECTION
WEDNESDAY NIGHT...SO I INCREASED POPS TO AROUND 50 PCT...WITH LESS
CERTAINTY IN DETAILS YET STILL CHANCE POPS FOR THU-FRI.
WHILE SHEAR IS NOT ALL THAT GREAT DURING THE PERIOD...DECENT CAPES
AND GENERAL PATTERN RECOGNITION WOULD SUGGEST THAT WE WILL HAVE TO
MONITOR POTENTIAL FOR SOME STRONG THUNDERSTORMS LATE WED THROUGH
FRI. MODELS DISAGREE FRIDAY ON TIMING OF COLD FRONT...BUT IF IT
OCCURS LATER IN THE DAY...IT WOULD BE MORE DIURNALLY FAVORABLE FOR
STRONGER CONVECTION.
&&
.LONG TERM /FRIDAY THROUGH SUNDAY/...
A FAIRLY LOW CONFIDENCE FCST FOR THE WEEKEND WITH DIFFS SHOWING UP
IN TIMING/LOCATION OF MEANDERING POLAR FNT ASSCD WITH S/WV`S
EMBEDDED IN GNRLY ZONAL FLOW. TREND APPEARS TO BE FOR MORE
TROFFING OFF THE NEW ENGLAND CST BY EARLY NXT WEEK BUT 00Z EURO
WAS A LTL SLOWER SHOWING IN THIS TREND. GFS HAS BEEN FAIRLY
CONSISTENT DRAGGING THRU THE POLAR FNT ON SAT WTIH INPROVING
CONDITIONS BY LATE IN THE DAY THEN RIDGING AND FAIR WX INTO MON.
HPC PROGS LEAN TWDS THE EURO WHICH DELAYS THE TROFFING AND FNTL
PSSG BY A DAY OR SO. GIVEN THE TIMING DIFFS...LEANED WITH THE
HPC/EURO GUIDANCE FOR THE XTNDD PD...GIVING CHC POPS FOR SHRA/TSRA
INTO SUNDAY...WITH A DRY FCST FOR MON. LTL CHG TO HPC TEMPS/POPS
AT THIS POINT...NO DOUBT THE FCST WILL BE CHANGING AS WE GET
CLOSER TO THE WEEKEND GIVEN THE UNCERTAINTY ASSCD WITH THIS PTRN.
&&
.AVIATION /18Z MONDAY THROUGH SATURDAY/...VFR THIS AFTN WITH SCT-
BKN MID/HI CLD. A FEW --SHRA PSBL AT ITH/SYR/RME THIS AFTN AS
INITIAL WEAK S/WV TRAVERSES THE RGN BUT NO RESTRICTIONS. LATER
TGNT AS A WMFNT APRCHS...CIGS WILL LOWER INTO THE IFR/MVFR RNG
WITH SHRA AND SCT TSRA. LOWER CLDS MAY GET INTO THE AVP AREA EARLY
THIS EVNG DUE TO MARINE LAYER WITH LOWER CLDS OVER SE PA SPREADING
NWD THIS AFTN/EVNG. A STRONG AND DEEP FNTL INVERSION DVLPS TNGT
BUT PROFILES SHOW A RATHER GRADUAL INCRS IN WIND SPEEDS THRU THIS
LAYER...SO WILL LEAVE MENTION ON LLWS OUT OF THE FCST FOR NOW.
BEST POTNL IF IT DVLPS APPEARS TO BE IN THE 06Z-12Z TIME FRAME.
XPCT AREA OF SHRA/TSRA TO EXIT ERN ZONES ARND 12Z OR SO...BUT LOW
CLDS AND MAYBE SOME PATCHY -DZ/BR LIKELY TO LINGER WITH IFR/MVFR.
WINDS THIS AFTN S TO SELY 5-10 KTS...GNRLY SELY TNGT 5-1O KTS WITH
G15 PSBL ON THE HILLTOPS...BECMG W TO NW BEHIND THE FNT ON MONDAY
10-15 KTS.
.OUTLOOK...
TUE NGT...PATCHY MVFR LATE AT NGT DUE TO BR/CIGS.
WED...VFR.
WED NGT/THU/FRU...PDS OF MVFR RESTRICTIONS DUE TO SHRA/TSRA.
&&
.FIRE WEATHER...
ANOTHER VERY DRY DAY IS FORECAST WITH MIN RH VALUES IN THE 20-25
PERCENT RANGE DURING THE AFTERNOON HOURS. HOWEVER WINDS WILL BE
MUCH LIGHTER THIS PERIOD, SO WE DO NOT EXPECT ANY FLAGS WILL BE
NEEDED.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DJP/MDP
NEAR TERM...DJP/HEDEN
SHORT TERM...MDP
FIRE WEATHER...
AREA FORECAST DISCUSSION...UPDATED
NWS CLEVELAND OH
615 PM EDT MON APR 30 2012
.SYNOPSIS...
LOW PRESSURE IS LOCATED OVER INDIANA WITH A WARM FRONT EAST ACROSS
NORTHERN OHIO TO WESTERN PENNSYLVANIA. A COLD FRONT EXTENDED
SOUTHWEST FROM THE LOW. THE LOW WILL TRACK NORTHEAST ACROSS LAKE
ERIE THIS EVENING...EVENTUALLY DRAGGING THE COLD FRONT ACROSS THE
AREA OVERNIGHT. HIGH PRESSURE WILL BUILD IN FOR TUESDAY MORNING.
TUESDAY EVENING INTO WEDNESDAY...THE FRONT WILL SURGE BACK NORTH
ACROSS THE AREA AS A WARM FRONT.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATED TO ADD SEVERE THUNDERSTORM WATCH 211 VALID UNTIL 1 AM.
ENCOMPASSES WEST OF A CUYAHOGA TO STARK COUNTY LINES...MINUS LUCAS AND
OTTAWA COUNTIES. SPC WANTED TO USE THE FRONTAL BOUNDARY LINGERING
JUST SOUTH OF THE LAKESHORE AS THE NORTHERN PERIPHERY OF THE WATCH
BOX.
LOW PRESSURE OVER INDIANA WILL MOVE ENE ACROSS LAKE ERIE THIS
EVENING. A WARM FRONT EAST OF THE LOW CURRENTLY EXTENDS ACROSS
NORTHWEST OHIO AND THE CENTRAL LAKESHORE AND THEN SOUTHEAST
THROUGH NORTHEAST OHIO INTO WESTERN PA. A COLD FRONT WILL FOLLOW
THE LOW MOVING ACROSS THE AREA OVERNIGHT. MAIN CONCERN FOR THIS
EVENING IS THE POTENTIAL FOR SEVERE WEATHER. WITH TEMPS IN THE
LOWER 80S IN THE WARM SECTOR ACROSS THE SOUTHERN TIER OF COUNTIES
AND DEWPOINTS NEAR 60...LI`S ARE NOW -2 TO -3 FROM FDY TO MFD.
EXPECT AIRMASS TO CONTINUE TO DESTABILIZE THROUGH 6 OR 7PM AND
THEN SLOWLY BEGIN TO BECOME MORE STABLE THROUGH THE EVENING.
FORECAST SOUNDINGS SHOW A GOOD MID LEVEL DRY SLOT INDICATING A
POTENTIAL FOR DOWN BURSTS AND AT LAST LOOK DOWNDRAFT CAPE HAD
REACHED 900J/KG. ALSO SURFACE BASED CAPES ARE JUST OVER 1000J/KG
ON RUC JUST TO OUR SOUTH AND WOULD EXPECT THAT AIR WILL BE LIFTED
NORTH INTO THE AREA THROUGH THE EVENING SO HAIL ALSO A POSSIBILITY.
RADAR SHOWS BAND OF RAIN FROM LOWER MI SOUTHWEST THRU NRN INDIANA
AND ILLINOIS WITH THUNDERSTORMS NOW DEVELOPING ON THE LEADING EDGE
OVER WEST CENTRAL INDIANA AND SRN ILLINOIS. EXPECT THESE TO TRACK
NORTHEAST WITH CURRENT MOTION BRINGING THUNDER FROM WESTERN
INDIANA INTO WESTERN CWA COUNTIES BETWEEN 8 AND 9PM. ...ALTHOUGH
DO EXPECT SHOWERS INTO NWRN BEFORE THEN. WILL HAVE CAT POPS FOR
THE ENTIRE AREA WITH THE POSSIBILITY OF SEVERE ACROSS ALL BUT THE
NORTHWEST CORNER. WILL CARRY THIS CHANCE OF SEVERE THROUGH THE
EVENING AND THEN TRANSITION TO SHOWERS OVERNIGHT WITH POPS ENDING
FROM THE NORTHWEST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
NEED TO BE BRIEF. TUESDAY MORNING SHOULD BEGIN DRY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH. THE COLD FRONT THAT MOVES
THROUGH TONIGHT SHOULD BE AROUND THE OHIO RIVER IN TE PROCESS OF
STALLING. TUESDAY AFTERNOON THE FRONT WILL TURN WARM AND REACH THE
SWRN CWA COUNTIES. DID BRING A CHANCE POP BACK TO THE WESTERN TWO
THIRDS BY EVENING DUE TO THE FRONT. CONTINUED CHANCE POPS TUESDAY
NIGHT GIVE THE FAIRLY MOIST AIRMASS ACROSS THE AREA AND THE FRONT
CONTINUING TO MOVE THROUGH. WEDNESDAY THE AREA WILL REMAIN IN THE
WARM SECTOR. MODELS DO SHOW ENOUGH MOISTURE ACROSS THE AREA FOR
CLOUDS AND THUNDERSTORMS HOWEVER GIVEN THE BUILDING SURFACE HIGH
SHAVED POPS TO LOW TO MID CHANCE. AIRMASS DRIES A BIT WEDNESDAY
NIGHT SO WILL DROP POPS MUCH OF THE AREA. THURSDAY SURFACE HIGH
STILL JUST SOUTHEAST OF THE AREA AND UPPER RIDGING TAKING PLACE AS
WELL. STARTED TO GO COMPLETELY DRY ALTHOUGH A BIT NERVOUS AS CAPES
ARE SHOWN OVER 2000J/KG DURING THE AFTERNOON SO PUT A SLIGHT
CHANCE IN THE GRAPHICS IN CASE CONVECTION BREAKS THROUGH THE CAP.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
BIG PICTURE HAS THE UPPER RIDGE BREAKING DOWN OVER THE COURSE OF THE
WEEKEND. FOR TIMING THIS FAR OUT HAVE TURNED TO THE GFS ENS AND TAKE
A COLD FRONT THROUGH THE AREA SLOWLY FRIDAY NIGHT INTO SATURDAY.
WILL HAVE TEMPS SLIGHTLY COOLER THAN THURSDAY...BUT STILL WARM.
SCATTERED SHOWERS AND THUNDERSTORMS WITH THE FRONT. COOLER FOR THE
SECOND HALF OF THE WEEKEND...RETURNING TO NEAR NORMAL WHEN THE HIGH
REALLY PUSHES DOWN INTO THE AREA.
&&
.AVIATION /22Z MONDAY THROUGH SATURDAY/...
ONLY MADE MINOR TIMING ADJUSTMENT TO THE TAFS FOR THE EXPECTED
SCATTERED SHRA/TS FOR LATER THIS AFTERNOON/EARLY EVENING. SOME OF
THESE STORMS COULD BE STRONG. WARM FRONT HAS LIFTED NORTHEAST OF
CLE AND CAK WITH A SHIFT IN WINDS TO SOUTH AND A BOOST IN
TEMPERATURES. LOW CENTER TO TRACK FROM NW IND ACROSS LAKE ERIE
THIS EVENING TAKING A COLD FRONT ACROSS OHIO. THIS WILL GENERATE
THE SHRA/TS. IN ITS WAKE TONIGHT...STILL INDICATIONS OF DEVELOPING
AN IFR DECK AND HAVE PLACED THAT INTO THE TAFS. HIGH PRESSURE
TUESDAY AND WE SHOULD SCATTER/CLEAR THAT DECK OUT IN THE MORNING
EASILY.
.OUTLOOK...NON-VFR CONDITIONS POSSIBLE WEDNESDAY WITHIN SHOWERS
AND THUNDERSTORMS. THURSDAY NIGHT INTO FRIDAY. NON VFR AGAIN
FRIDAY INTO SATURDAY WITH SHOWERS/THUNDERSTORMS.
&&
.MARINE...
GENERALLY QUIET CONDITIONS EXPECTED ON THE LAKE THROUGH THE NEXT 5
DAYS. NOT EXPECTING WAVES GREATER THAN 2 FEET THROUGH THE PERIOD.
THIS IS ALL DUE TO THE FACT THERE WILL BE NO MAJOR WEATHER SYSTEMS
AFFECTING LAKE ERIE DURING THIS TIME PERIOD. ONLY PROBLEMS TO
CONTEND WITH IS THE THREAT FOR THUNDERSTORMS LATER THIS EVENING.
THERE WILL ALSO BE A CHANCE FOR SHOWERS AND THUNDERSTORMS AT LEAST
THROUGH FRIDAY. ONE THING TO KEEP IN MIND IS THE THREAT FOR SEVERE
THUNDERSTORMS LATER THIS EVENING ON THE LAKE. MARINERS SHOULD KEEP A
CLOSE WATCH TO THE SKY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...DJB/TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
340 PM EDT MON APR 30 2012
.SYNOPSIS...
LOW PRESSURE IS LOCATED OVER INDIANA WITH A WARM FRONT EAST ACROSS
NORTHERN OHIO TO WESTERN PENNSYLVANIA. A COLD FRONT EXTENDED
SOUTHWEST FROM THE LOW. THE LOW WILL TRACK NORTHEAST ACROSS LAKE
ERIE THIS EVENING...EVENTUALLY DRAGGING THE COLD FRONT ACROSS THE
AREA OVERNIGHT. HIGH PRESSURE WILL BUILD IN FOR TUESDAY MORNING.
TUESDAY EVENING INTO WEDNESDAY...THE FRONT WILL SURGE BACK NORTH
ACROSS THE AREA AS A WARM FRONT.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW PRESSURE OVER INDIANA WILL MOVE ENE ACROSS LAKE ERIE THIS
EVENING. A WARM FRONT EAST OF THE LOW CURRENTLY EXTENDS ACROSS
NORTHWEST OHIO AND THE CENTRAL LAKESHORE AND THEN SOUTHEAST
THROUGH NORTHEAST OHIO INTO WESTERN PA. A COLD FRONT WILL FOLLOW
THE LOW MOVING ACROSS THE AREA OVERNIGHT. MAIN CONCERN FOR THIS
EVENING IS THE POTENTIAL FOR SEVERE WEATHER. WITH TEMPS IN THE
LOWER 80S IN THE WARM SECTOR ACROSS THE SOUTHERN TIER OF COUNTIES
AND DEWPOINTS NEAR 60...LI`S ARE NOW -2 TO -3 FROM FDY TO MFD.
EXPECT AIRMASS TO CONTINUE TO DESTABILIZE THROUGH 6 OR 7PM AND
THEN SLOWLY BEGIN TO BECOME MORE STABLE THROUGH THE EVENING.
FORECAST SOUNDINGS SHOW A GOOD MID LEVEL DRY SLOT INDICATING A
POTENTIAL FOR DOWN BURSTS AND AT LAST LOOK DOWNDRAFT CAPE HAD
REACHED 900J/KG. ALSO SURFACE BASED CAPES ARE JUST OVER 1000J/KG
ON RUC JUST TO OUR SOUTH AND WOULD EXPECT THAT AIR WILL BE LIFTED
NORTH INTO THE AREA THROUGH THE EVENING SO HAIL ALSO A POSSIBILITY.
RADAR SHOWS BAND OF RAIN FROM LOWER MI SOUTHWEST THRU NRN INDIANA
AND ILLINOIS WITH THUNDERSTORMS NOW DEVELOPING ON THE LEADING EDGE
OVER WEST CENTRAL INDIANA AND SRN ILLINOIS. EXPECT THESE TO TRACK
NORTHEAST WITH CURRENT MOTION BRINGING THUNDER FROM WESTERN
INDIANA INTO WESTERN CWA COUNTIES BETWEEN 8 AND 9PM. ...ALTHOUGH
DO EXPECT SHOWERS INTO NWRN BEFORE THEN. WILL HAVE CAT POPS FOR
THE ENTIRE AREA WITH THE POSSIBILITY OF SEVERE ACROSS ALL BUT THE
NORTHWEST CORNER. WILL CARRY THIS CHANCE OF SEVERE THROUGH THE
EVENING AND THEN TRANSITION TO SHOWERS OVERNIGHT WITH POPS ENDING
FROM THE NORTHWEST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY NIGHT/...
NEED TO BE BRIEF. TUESDAY MORNING SHOULD BEGIN DRY WITH HIGH
PRESSURE BUILDING IN FROM THE NORTH. THE COLD FRONT THAT MOVES
THROUGH TONIGHT SHOULD BE AROUND THE OHIO RIVER IN TE PROCESS OF
STALLING. TUESDAY AFTERNOON THE FRONT WILL TURN WARM AND REACH THE
SWRN CWA COUNTIES. DID BRING A CHANCE POP BACK TO THE WESTERN TWO
THIRDS BY EVENING DUE TO THE FRONT. CONTINUED CHANCE POPS TUESDAY
NIGHT GIVE THE FAIRLY MOIST AIRMASS ACROSS THE AREA AND THE FRONT
CONTINUING TO MOVE THROUGH. WEDNESDAY THE AREA WILL REMAIN IN THE
WARM SECTOR. MODELS DO SHOW ENOUGH MOISTURE ACROSS THE AREA FOR
CLOUDS AND THUNDERSTORMS HOWEVER GIVEN THE BUILDING SURFACE HIGH
SHAVED POPS TO LOW TO MID CHANCE. AIRMASS DRIES A BIT WEDNESDAY
NIGHT SO WILL DROP POPS MUCH OF THE AREA. THURSDAY SURFACE HIGH
STILL JUST SOUTHEAST OF THE AREA AND UPPER RIDGING TAKING PLACE AS
WELL. STARTED TO GO COMPLETELY DRY ALTHOUGH A BIT NERVOUS AS CAPES
ARE SHOWN OVER 2000J/KG DURING THE AFTERNOON SO PUT A SLIGHT
CHANCE IN THE GRAPHICS IN CASE CONVECTION BREAKS THROUGH THE CAP.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
BIG PICTURE HAS THE UPPER RIDGE BREAKING DOWN OVER THE COURSE OF THE
WEEKEND. FOR TIMING THIS FAR OUT HAVE TURNED TO THE GFS ENS AND TAKE
A COLD FRONT THROUGH THE AREA SLOWLY FRIDAY NIGHT INTO SATURDAY.
WILL HAVE TEMPS SLIGHTLY COOLER THAN THURSDAY...BUT STILL WARM.
SCATTERED SHOWERS AND THUNDERSTORMS WITH THE FRONT. COOLER FOR THE
SECOND HALF OF THE WEEKEND...RETURNING TO NEAR NORMAL WHEN THE HIGH
REALLY PUSHES DOWN INTO THE AREA.
&&
.AVIATION /19Z MONDAY THROUGH SATURDAY/...
ONLY MADE MINOR TIMING ADJUSTMENT TO THE TAFS FOR THE EXPECTED
SCATTERED SHRA/TS FOR LATER THIS AFTERNOON/EARLY EVENING. SOME OF
THESE STORMS COULD BE STRONG. WARM FRONT HAS LIFTED NORTHEAST OF
CLE AND CAK WITH A SHIFT IN WINDS TO SOUTH AND A BOOST IN
TEMPERATURES. LOW CENTER TO TRACK FROM NW IND ACROSS LAKE ERIE
THIS EVENING TAKING A COLD FRONT ACROSS OHIO. THIS WILL GENERATE
THE SHRA/TS. IN ITS WAKE TONIGHT...STILL INDICATIONS OF DEVELOPING
AN IFR DECK AND HAVE PLACED THAT INTO THE TAFS. HIGH PRESSURE
TUESDAY AND WE SHOULD SCATTER/CLEAR THAT DECK OUT IN THE MORNING
EASILY.
.OUTLOOK...NON-VFR CONDITIONS POSSIBLE WEDNESDAY WITHIN SHOWERS
AND THUNDERSTORMS. THURSDAY NIGHT INTO FRIDAY. NON VFR AGAIN
FRIDAY INTO SATURDAY WITH SHOWERS/THUNDERSTORMS.
&&
.MARINE...
GENERALLY QUIET CONDITIONS EXPECTED ON THE LAKE THROUGH THE NEXT 5
DAYS. NOT EXPECTING WAVES GREATER THAN 2 FEET THROUGH THE PERIOD.
THIS IS ALL DUE TO THE FACT THERE WILL BE NO MAJOR WEATHER SYSTEMS
AFFECTING LAKE ERIE DURING THIS TIME PERIOD. ONLY PROBLEMS TO
CONTEND WITH IS THE THREAT FOR THUNDERSTORMS LATER THIS EVENING.
THERE WILL ALSO BE A CHANCE FOR SHOWERS AND THUNDERSTORMS AT LEAST
THROUGH FRIDAY. ONE THING TO KEEP IN MIND IS THE THREAT FOR SEVERE
THUNDERSTORMS LATER THIS EVENING ON THE LAKE. MARINERS SHOULD KEEP A
CLOSE WATCH TO THE SKY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...TK
SHORT TERM...TK
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...LOMBARDY
AREA FORECAST DISCUSSION
NWS TULSA OK
1159 AM CDT MON APR 30 2012
.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
TSRA DEVELOPING LATE THIS MORNING IN SE OK/W CNTRL AR...WHICH WILL
NECESSITATE A VCTS AT MLC AND FSM THIS AFTN. CANNOT RULE OUT
DEVELOPMENT THIS AFTERNOON FURTHER NORTH...BUT THINK THAT MOST OF
IT WILL BE AFTER 00Z. MESOSCALE MODELS HINTING AT ANOTHER MCS
MOVING THROUGH NE OK/NW AR TONIGHT...SO WILL GO WITH PROB30S FOR
THIS SCENARIO AT ALL TERMINALS EXCEPT MLC/FSM. IFR CONDITIONS WILL
BE POSSIBLE...ESPECIALLY IN NE OK...DURING THE THUNDERSTORMS.
GUSTY SOUTH WINDS POSSIBLE LATE IN THE TAF PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1040 AM CDT MON APR 30 2012/
..UPDATE...
DISCUSSION...
MORNING THUNDERSTORMS CONTINUE TO PUSH OFF TO THE EAST...AND WILL
LIKELY BE OUT OF THE FORECAST AREA BY 18Z. FORECAST WILL BE
UPDATED AT LEAST ONCE THIS AFTERNOON AFTER THESE STORMS HAVE
TOTALLY CLEARED THE AREA. ADDITIONAL THUNDERSTORM DEVELOPMENT THIS
AFTERNOON IS HINTED AT BY BOTH THE HRRR AND THE LOCAL WRF...MAINLY
ACROSS NORTHEAST OKLAHOMA. HAVE RETOOLED POPS TO SHOW HIGHER
VALUES NEAR THE KANSAS BORDER...TAPERING TO LOWER VALUES SOUTH OF
INTERSTATE 40.
SOME CLEARING IS OCCURRING ON THE BACKSIDE OF THE STORMS...AND IF
THIS TREND CONTINUES ACROSS THE SOUTHEASTERN HALF OF THE
AREA...FORECAST HIGHS SHOULD STILL BE REALIZED. WILL NOT CHANGE
HIGHS ATTM...BUT WILL CONTINUE TO MONITOR AND MAKE ADJUSTMENTS AS
NEEDED BEFORE ANY AFTERNOON UPDATES.
TWEAKS HAVE BEEN MADE TO OTHER ELEMENTS ACCORDING TO CURRENT
TRENDS.
PREV DISCUSSION... /ISSUED 624 AM CDT MON APR 30 2012/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM.
LINE OF THUNDERSTORMS WITH TRAILING AREA OF STRATIFORM RAIN WILL
CONTINUE TO PROGRESS EAST THIS MORNING...WILL BE ONGOING AT
MLC/FSM/FYV AT ISSUANCE TIME WITH MVFR CONDITIONS PREVAILING. ONCE
THIS CLEARS THE AREA...VFR CONDITIONS EXPECTED TO PREVAIL THROUGH
THE REST OF THE PERIOD. CONFIDENCE REGARDING ADDITIONAL
THUNDERSTORM DEVELOPMENT THIS AFTERNOON ALONG ANY OUTFLOW BOUNDARY
REMAINS TOO LOW AT THIS POINT TO INCLUDE ANY MENTION IN THE
FORECAST. SHOULD ANY STORMS OCCUR...LOCAL MVFR CONDITIONS WILL BE
LIKELY.
PREV DISCUSSION... /ISSUED 329 AM CDT MON APR 30 2012/
DISCUSSION...
A WEAKENING AREA OF SHOWERS AND THUNDERSTORMS IS PROGRESSING
SOUTHEAST ACROSS NORTHEAST OKLAHOMA EARLY THIS MORNING AND LATEST
RUNS OF THE HRRR SUGGEST THAT AT LEAST A BROKEN BAND OF SHOWERS
AND STORMS WILL MAKE IT THROUGH ALL OF EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS THIS MORNING. RESIDUAL OUTFLOW BOUNDARIES AND
THE OLD FRONTAL BOUNDARY NEAR THE KANSAS AND MISSOURI BORDERS MAY
PROVIDE A FOCUS FOR RENEWED DEVELOPMENT LATER THIS AFTERNOON OR
THIS EVENING BUT BY LATER TONIGHT THE GREATEST CONVECTIVE COVERAGE
IS LIKELY TO BE TO OUR NORTH AND NORTHEAST.
WILL CONTINUE LOW POPS INTO TUESDAY BUT AFTER THAT THE CAPPING
INVERSION STRENGTHENS ENOUGH TO PRECLUDE A MENTION OF CONVECTION.
VERY WARM AND HUMID WEATHER WILL THEN PREVAIL THROUGH AT LEAST
NEXT WEEKEND WITH HIGHS APPROACHING 90 AND LOWS NEAR 70 IN MANY
PLACES.
STAYED CLOSE TO THE WARMER NAM MOS TEMPERATURES THE NEXT COUPLE
DAYS.
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...22
LONG TERM....23
AVIATION...22
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
345 PM CDT MON APR 30 2012
.UPDATE...
THE SEVERE THUNDERSTORM WATCH WILL BE EXPANDED TO INCLUDE THE
BIG SPRING...LAMESA...COLORADO CITY AND SNYDER AREAS.
SEVERE THUNDERSTORM WATCH #209 REMAIN IN EFFECT UNTIL 10 PM CDT.
&&
.EARLIER DISCUSSION /200 PM CDT MON APR 30 2012/...
THUNDERSTORMS ARE ALREADY FIRING IN THE DAVIS MOUNTAINS THIS
AFTERNOON...AND MODELS ARE INDICATING MORE WILL DEVELOP ALONG THE
DRYLINE IN THE CENTRAL PERMIAN BASIN LATER THIS AFTERNOON. THE
MAIN QUESTION IS A SLIGHT ELEVATED WARM LAYER AROUND 700MB THAT IS
CURRENTLY STIFLING CONVECTION. THE NAM SHOWS THIS LAYER ERODING BY
00Z WHILE THE RUC NEVER QUITE DOES. CORRESPONDINGLY THE NAM IS
MORE AGGRESSIVE BREAKING OUT PRECIP ACROSS THE AREA THAN THE RUC.
THERE IS NO WAY TO TELL FOR SURE WHICH IS CORRECT BUT THE CURRENT
SATELLITE SHOWS THE CAP IS STILL WELL IN PLACE WITH CUMULUS IN THE
EASTERN BASIN TO GO ALONG WITH THE MOUNTAIN TS. EITHER WAY THERE
WILL PROBABLY BE AT LEAST A COUPLE MORE HOURS BEFORE ANY
CONVECTION STARTS ALONG THE DRYLINE. WENT AHEAD AND PLACED MENTION
OF SEVERE TS IN THE FORECAST MATCHING WELL THE LATEST SWODY1
PRODUCT FROM SPC DUE TO CAPE IN EXCESS OF 2000J/KG AND 0-6KM SHEAR
VALUES 30-40KTS OR GREATER.
DRYLINE CONVECTION WILL CONTINUE TO BE POSSIBLE OVER THE NEXT
SEVERAL DAYS. A SHORTWAVE TROUGH WILL MOVE UP OUT OF MEXICO
WEDNESDAY BUT MAY BE TOO EARLY WITH THE SUBSIDENCE REGION OVER THE
AREA DURING PEAK HEATING. SHOULD THIS FEATURE SLOW BY 6-12 HOURS
RAIN CHANCES COULD BE A BIT HIGHER. OTHERWISE WEST TO SOUTHWEST
UPPER LEVEL FLOW WILL CONTINUE THE WELL ABOVE NORMAL TEMPERATURES
ACROSS THE CWA.
&&
.FIRE WEATHER...
LOW END RED FLAG CONDITIONS EXPECTED IN SOUTHEASTERN NEW MEXICO
TOMORROW AND SHOULD CONTINUE INTO WEDNESDAY. THE LIMITING FACTOR
WILL BE WIND SPEEDS WHICH WILL BE MARGINAL ON TUESDAY AND SLIGHTLY
STRONGER ON WEDNESDAY. THE FIRE WEATHER WATCH WEDNESDAY MAY NEED
TO BE EXTENDED SLIGHTLY SOUTH AND EAST...BUT A WEAK SURFACE
PRESSURE GRADIENT ALONG THE DRYLINE WILL LIMIT THE STRONGER WINDS
TO THE UPPER TRANS PECOS AND AREAS FURTHER WEST. THERE WILL BE
EXCELLENT HUMIDITY RECOVERY ALL AREAS TONIGHT EXCEPT THE GUADALUPE
MOUNTAINS. THE DRYLINE WILL NOT BE ABLE TO RETREAT AS FAR TOMORROW
NIGHT WITH POOR RECOVERY EXPECTED FROM THE UPPER TRANS PECOS TO
THE DAVIS MOUNTAINS AND LOCATIONS FURTHER WEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 64 94 63 93 / 20 20 20 10
BIG SPRING TX 66 92 67 93 / 30 20 20 10
CARLSBAD NM 60 94 61 95 / 10 10 10 10
DRYDEN TX 66 90 67 94 / 20 20 20 20
FORT STOCKTON TX 65 94 65 96 / 20 20 20 10
GUADALUPE PASS TX 56 80 56 79 / 0 0 10 10
HOBBS NM 61 93 58 94 / 10 10 10 10
MARFA TX 57 87 56 86 / 20 10 10 10
MIDLAND INTL AIRPORT TX 66 92 66 94 / 20 20 20 10
ODESSA TX 66 93 66 94 / 20 20 20 10
WINK TX 64 97 63 98 / 10 10 10 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...RED FLAG WARNING FROM 10 AM TO 8 PM MDT TUESDAY FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS NP/LINCOLN NF/LNZ...
SOUTHEAST PLAINS/BLM ROSWELL/LNZ.
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES... GUADALUPE MOUNTAINS
NP/LINCOLN NF/LNZ...SOUTHEAST PLAINS/BLM ROSWELL/LNZ.
TX...RED FLAG WARNING FROM 10 AM TO 8 PM MDT TUESDAY FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS.
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES... GUADALUPE MOUNTAINS.
&&
$$
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
245 PM CDT MON APR 30 2012
.UPDATE...
SEVERE THUNDERSTORM WATCH #209 IN EFFECT UNTIL 10 PM CDT.
&&
.EARLIER DISCUSSION /200 PM CDT MON APR 30 2012/...
THUNDERSTORMS ARE ALREADY FIRING IN THE DAVIS MOUNTAINS THIS
AFTERNOON...AND MODELS ARE INDICATING MORE WILL DEVELOP ALONG THE
DRYLINE IN THE CENTRAL PERMIAN BASIN LATER THIS AFTERNOON. THE
MAIN QUESTION IS A SLIGHT ELEVATED WARM LAYER AROUND 700MB THAT IS
CURRENTLY STIFLING CONVECTION. THE NAM SHOWS THIS LAYER ERODING BY
00Z WHILE THE RUC NEVER QUITE DOES. CORRESPONDINGLY THE NAM IS
MORE AGGRESSIVE BREAKING OUT PRECIP ACROSS THE AREA THAN THE RUC.
THERE IS NO WAY TO TELL FOR SURE WHICH IS CORRECT BUT THE CURRENT
SATELLITE SHOWS THE CAP IS STILL WELL IN PLACE WITH CUMULUS IN THE
EASTERN BASIN TO GO ALONG WITH THE MOUNTAIN TS. EITHER WAY THERE
WILL PROBABLY BE AT LEAST A COUPLE MORE HOURS BEFORE ANY
CONVECTION STARTS ALONG THE DRYLINE. WENT AHEAD AND PLACED MENTION
OF SEVERE TS IN THE FORECAST MATCHING WELL THE LATEST SWODY1
PRODUCT FROM SPC DUE TO CAPE IN EXCESS OF 2000J/KG AND 0-6KM SHEAR
VALUES 30-40KTS OR GREATER.
DRYLINE CONVECTION WILL CONTINUE TO BE POSSIBLE OVER THE NEXT
SEVERAL DAYS. A SHORTWAVE TROUGH WILL MOVE UP OUT OF MEXICO
WEDNESDAY BUT MAY BE TOO EARLY WITH THE SUBSIDENCE REGION OVER THE
AREA DURING PEAK HEATING. SHOULD THIS FEATURE SLOW BY 6-12 HOURS
RAIN CHANCES COULD BE A BIT HIGHER. OTHERWISE WEST TO SOUTHWEST
UPPER LEVEL FLOW WILL CONTINUE THE WELL ABOVE NORMAL TEMPERATURES
ACROSS THE CWA.
&&
.FIRE WEATHER...
LOW END RED FLAG CONDITIONS EXPECTED IN SOUTHEASTERN NEW MEXICO
TOMORROW AND SHOULD CONTINUE INTO WEDNESDAY. THE LIMITING FACTOR
WILL BE WIND SPEEDS WHICH WILL BE MARGINAL ON TUESDAY AND SLIGHTLY
STRONGER ON WEDNESDAY. THE FIRE WEATHER WATCH WEDNESDAY MAY NEED
TO BE EXTENDED SLIGHTLY SOUTH AND EAST...BUT A WEAK SURFACE
PRESSURE GRADIENT ALONG THE DRYLINE WILL LIMIT THE STRONGER WINDS
TO THE UPPER TRANS PECOS AND AREAS FURTHER WEST. THERE WILL BE
EXCELLENT HUMIDITY RECOVERY ALL AREAS TONIGHT EXCEPT THE GUADALUPE
MOUNTAINS. THE DRYLINE WILL NOT BE ABLE TO RETREAT AS FAR TOMORROW
NIGHT WITH POOR RECOVERY EXPECTED FROM THE UPPER TRANS PECOS TO
THE DAVIS MOUNTAINS AND LOCATIONS FURTHER WEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 64 94 63 93 / 20 20 20 10
BIG SPRING TX 66 92 67 93 / 30 20 20 10
CARLSBAD NM 60 94 61 95 / 10 10 10 10
DRYDEN TX 66 90 67 94 / 20 20 20 20
FORT STOCKTON TX 65 94 65 96 / 20 20 20 10
GUADALUPE PASS TX 56 80 56 79 / 0 0 10 10
HOBBS NM 61 93 58 94 / 10 10 10 10
MARFA TX 57 87 56 86 / 20 10 10 10
MIDLAND INTL AIRPORT TX 66 92 66 94 / 20 20 20 10
ODESSA TX 66 93 66 94 / 20 20 20 10
WINK TX 64 97 63 98 / 10 10 10 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...RED FLAG WARNING FROM 10 AM TO 8 PM MDT TUESDAY FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS NP/LINCOLN NF/LNZ...
SOUTHEAST PLAINS/BLM ROSWELL/LNZ.
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES... GUADALUPE MOUNTAINS
NP/LINCOLN NF/LNZ...SOUTHEAST PLAINS/BLM ROSWELL/LNZ.
TX...RED FLAG WARNING FROM 10 AM TO 8 PM MDT TUESDAY FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS.
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES... GUADALUPE MOUNTAINS.
&&
$$
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
226 PM CDT MON APR 30 2012
.SHORT TERM...
WE ARE BASICALLY IN A WAIT AND SEE MODE FOR WHEN/IF SEVERE WEATHER
WILL INITIATE. 19Z RADAR IMAGE SHOWS TWO BOUNDARIES ACROSS THE
AREA...FIRST ONE WAS LOCATED SOUTHWEST OF LUBBOCK WHICH WAS ORIENTED
NORTHWEST TO SOUTHEAST WITH THE SECOND ONE LOCATED OVER THE ROLLING
PLAINS ORIENTED NORTH/SOUTH. LATEST VISIBLE SATELLITE IMAGERY AND
OFFICE TOWER CAMERA ARE SHOWING CU FIELD TRYING TO DEVELOP ALONG
THIS BOUNDARY WHILE SKIES ARE TRYING TO CLEAR IMMEDIATELY
EAST/NORTHEAST OF THE BOUNDARY. THERE IS LITTLE IN THE WAY OF
DYNAMICS TO HELP SHARPEN THE DRYLINE AND PUSH IT EAST SO FEEL THAT
THE WESTERN BOUNDARY SHOULD NOT MOVE TOO MUCH FURTHER EAST.
DEWPOINTS IMMEDIATELY NORTH AND EAST OF THE BOUNDARY HAVE ACTUALLY
BEEN SLOWLY RISING AS EVAPORATION TAKES PLACE FROM THE RAINFALL
YESTERDAY WHICH SHOULD ALSO HELP TO SHARPEN UP THE BOUNDARY A BIT.
19Z RUC RUN KEEPS KLBB CAPPED ALTHOUGH STRENGTH OF THE CAP IS NOT
INSURMOUNTABLE AND THE LATEST HRRR RUNS CONTINUE TO TRY AND BREAK
OUT CONVECTION. THUS...SEVERE WEATHER THREAT STILL LOOKS GOOD WITH
MAIN THREATS LARGE HAIL UP TO BASEBALL SIZE AS WELL AS DAMAGING
WINDS... BUT AN ISOLATED TORNADO STILL REMAINS POSSIBLE.
FORECAST FOR TONIGHT INTO TOMORROW WILL HINGE ON HOW THINGS DEVELOP
THIS AFTERNOON. LOW TEMPS WILL REMAIN A FEW DEGREES ABOVE NORMAL
OVER MOST OF THE AREA AS RICH LOW LEVEL MOISTURE REMAIN IN PLACE
OVER THE REGION. DRYLINE TOMORROW MAY TRY TO PUSH A BIT FURTHER
EAST TOMORROW BUT POOR HANDLE OF THE DRYLINE LAST SEVERAL RUNS IN
THE MODELS MAKE ME A BIT SUSPICIOUS OF WHERE IT MAY BE LOCATED
TOMORROW. IF THE WIND DOES INCREASE OUT OF THE SOUTHWEST...
TEMPERATURES WEST OF THE DRYLINE MAY JUMP INTO THE LOW/MID 90S WHILE
ALONG AND EAST OF THE DRYLINE...TEMPERATURES WILL REMAIN IN THE
80S. ALSO WENT AHEAD AND BUMPED POPS UP INTO THE LOW END OF SLIGHT
CHANCE FOR THE ROLLING PLAINS AS THERE WILL ONCE AGAIN BE QUITE A
BIT OF INSTABILITY EAST OF THE DRYLINE ALTHOUGH CAP STRENGTH MAY
LIMIT THE AMOUNT OF CONVECTION FOR TOMORROW.
JORDAN
&&
.LONG TERM...
AN UA LOW ACROSS THE EASTERN PACIFIC IS PROGGED TO NEAR THE BAJA OF
CALIFORNIA LATE TOMORROW NIGHT/EARLY WEDNESDAY MORNING...THUS
PROMOTING THE SHARPENING OF SW FLOW ALOFT. AS SUCH...THE DRYLINE
WILL BE A PROMINENT MESOSCALE FEATURE THROUGHOUT THE EXTENDED
FORECAST. FORECAST MODELS HINT AT QPF ALONG THE DRYLINE /LOCATED OFF
THE CAPROCK/ TOMORROW NIGHT...AS AN IMPULSE IN THE SW FLOW ALOFT
MOVES ACROSS THE SOUTH PLAINS. FORECAST SOLUTIONS DISPLAYED ADEQUATE
CONVERGENCE ALONG THE DRYLINE...PWATS AOA 1.00 INCH AND SFC AND MID
LEVEL INSTABILITY/CAPE OF APPROXIMATELY 1200 J/KG ACROSS THE ROLLING
PLAINS. ALTHOUGH PROGGED MODEL SOUNDINGS EXHIBITED MOISTENED
MID-LEVELS...LOW LEVELS APPEAR RELATIVELY DRY. CURRENT THINKING IS
THAT GUSTY WINDS WILL BE THE PRIMARY THREATS...WITH LITTLE RAINFALL
ACCUMULATION. HOWEVER...HAVE OPTED TO ADD MENTIONABLE POPS ACROSS
THE ROLLING PLAINS NEAREST TO THE BEST MOISTURE AXIS...AS THE
AFOREMENTIONED EMBEDDED DISTURBANCE MAY JUST BE THE SYNOPTIC SPARK
TO INITIATE STORMS. BY THURSDAY THE UA LOW WILL BE TRANSLATING
ACROSS THE BAJA OF CALIFORNIA. ONCE AGAIN THERE ARE HINTS OF CI JUST
SOUTH OF THE CWA ALONG THE DRYLINE...WHICH IS SPATIALLY DISTRIBUTED
ON THE CAPROCK EARLY THURSDAY MORNING. HOWEVER EMBEDDED IMPULSES IN
THE FLOW ALOFT BRUSHING THE FAR SERN ZONES THURSDAY NIGHT COULD
PROMOTE ADDITIONAL CHANCES OF PRECIP ACROSS THE SOUTHERN ROLLING
PLAINS. WILL HOLD OFF ON A PRECIP MENTION ATTM...AS BEST INSTABILITY
APPEARS TO BE SE OF THE FA.
THEREAFTER...UA RIDGING WILL COMMENCE TO MOVE EAST ACROSS THE REGION
FRI-SAT AS LACK OF PRECIP DESPITE A LINGERING DRYLINE SUGGESTS A
DECENT CAPPING INVERSION AT PLAY. WILL HOWEVER NEED TO MONITOR LATER
MODEL RUNS AS TEMPS IN THE 90S MAY BE ENOUGH TO BREAK THE CAP...AND
INITIATE THUNDERSTORM DEVELOPMENT. THE INFLUENCE OF THE UA RIDGE
WILL BE SHORT-LIVED AS IT SHIFTS EAST OF THE SOUTHERN PLAINS BY
SUNDAY...THANKS TO A NW PACIFIC UA LOW DEEPENING ACROSS THE GREAT
BASIN /THIS IS A RADICAL CHANGE FROM THE PREVIOUS RUN/. HINTS OF
CONVECTION OCCURRING NEAR THE STATE LINE ALONG THE DRYLINE
SUNDAY/MONDAY MORNING IS DISPLAYED BY BOTH THE GFS AND ECMWF
SOLUTIONS. WILL HOWEVER MAINTAIN SILENT POPS ATTM SINCE NEXT MONDAY
IS DAY 7 AND AS MENTIONED...A LOT OF THINGS CAN CHANGE.
&&
.FIRE WEATHER...
A DRYLINE IS EXPECTED TO SHARPEN ACROSS THE ROLLING PLAINS ON
WEDNESDAY...AND ALLOW DRIER AIR WEST OF THE DRYLINE...TO FILTER
ACROSS PORTIONS OF THE REGION. TEMPS APPROXIMATELY 15 DEGREES ABOVE
NORMAL WILL PROMOTE RELATIVE HUMIDITY VALUES TO FALL BELOW 15
PERCENT...AS 20-FOOT WIND SPEEDS NEAR/SLIGHTLY EXCEED 20 MPH. AS A
RESULT...ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS MAY
OCCUR...AND A MENTION BEYOND THE HAZARDOUS WEATHER OUTLOOK MAY BE
WARRANTED. ONLY MITIGATING FACTOR MAY WHERE AND HOW MUCH EXPECTED
RAINFALL THE AREA WILL RECEIVE TODAY...WHICH COULD PROMOTE GREENUP
AND HIGHER RELATIVE HUMIDITY VALUES THAN ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 55 91 55 88 53 / 30 0 0 0 0
TULIA 60 92 58 90 55 / 40 10 10 10 10
PLAINVIEW 61 93 59 91 57 / 40 10 10 10 10
LEVELLAND 61 92 59 93 58 / 10 10 10 10 10
LUBBOCK 63 92 61 94 60 / 20 10 10 10 10
DENVER CITY 59 94 58 93 58 / 10 10 10 10 10
BROWNFIELD 62 94 59 94 58 / 10 10 10 10 10
CHILDRESS 64 92 64 94 62 / 40 20 20 10 10
SPUR 66 91 62 94 60 / 40 20 20 10 10
ASPERMONT 68 91 64 97 63 / 40 20 20 10 20
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
14/29
AREA FORECAST DISCUSSION
NWS MIDLAND/ODESSA TX
200 PM CDT MON APR 30 2012
.DISCUSSION...
THUNDERSTORMS ARE ALREADY FIRING IN THE DAVIS MOUNTAINS THIS
AFTERNOON...AND MODELS ARE INDICATING MORE WILL DEVELOP ALONG THE
DRYLINE IN THE CENTRAL PERMIAN BASIN LATER THIS AFTERNOON. THE
MAIN QUESTION IS A SLIGHT ELEVATED WARM LAYER AROUND 700MB THAT IS
CURRENTLY STIFLING CONVECTION. THE NAM SHOWS THIS LAYER ERODING BY
00Z WHILE THE RUC NEVER QUITE DOES. CORRESPONDINGLY THE NAM IS
MORE AGGRESSIVE BREAKING OUT PRECIP ACROSS THE AREA THAN THE RUC.
THERE IS NO WAY TO TELL FOR SURE WHICH IS CORRECT BUT THE CURRENT
SATELLITE SHOWS THE CAP IS STILL WELL IN PLACE WITH CUMULUS IN THE
EASTERN BASIN TO GO ALONG WITH THE MOUNTAIN TS. EITHER WAY THERE
WILL PROBABLY BE AT LEAST A COUPLE MORE HOURS BEFORE ANY
CONVECTION STARTS ALONG THE DRYLINE. WENT AHEAD AND PLACED MENTION
OF SEVERE TS IN THE FORECAST MATCHING WELL THE LATEST SWODY1
PRODUCT FROM SPC DUE TO CAPE IN EXCESS OF 2000J/KG AND 0-6KM SHEAR
VALUES 30-40KTS OR GREATER.
DRYLINE CONVECTION WILL CONTINUE TO BE POSSIBLE OVER THE NEXT
SEVERAL DAYS. A SHORTWAVE TROUGH WILL MOVE UP OUT OF MEXICO
WEDNESDAY BUT MAY BE TOO EARLY WITH THE SUBSIDENCE REGION OVER THE
AREA DURING PEAK HEATING. SHOULD THIS FEATURE SLOW BY 6-12 HOURS
RAIN CHANCES COULD BE A BIT HIGHER. OTHERWISE WEST TO SOUTHWEST
UPPER LEVEL FLOW WILL CONTINUE THE WELL ABOVE NORMAL TEMPERATURES
ACROSS THE CWA.
&&
.FIRE WEATHER...
LOW END RED FLAG CONDITIONS EXPECTED IN SOUTHEASTERN NEW MEXICO
TOMORROW AND SHOULD CONTINUE INTO WEDNESDAY. THE LIMITING FACTOR
WILL BE WIND SPEEDS WHICH WILL BE MARGINAL ON TUESDAY AND SLIGHTLY
STRONGER ON WEDNESDAY. THE FIRE WEATHER WATCH WEDNESDAY MAY NEED
TO BE EXTENDED SLIGHTLY SOUTH AND EAST...BUT A WEAK SURFACE
PRESSURE GRADIENT ALONG THE DRYLINE WILL LIMIT THE STRONGER WINDS
TO THE UPPER TRANS PECOS AND AREAS FURTHER WEST. THERE WILL BE
EXCELLENT HUMIDITY RECOVERY ALL AREAS TONIGHT EXCEPT THE GUADALUPE
MOUNTAINS. THE DRYLINE WILL NOT BE ABLE TO RETREAT AS FAR TOMORROW
NIGHT WITH POOR RECOVERY EXPECTED FROM THE UPPER TRANS PECOS TO
THE DAVIS MOUNTAINS AND LOCATIONS FURTHER WEST.
&&
.PRELIMINARY POINT TEMPS/POPS...
ANDREWS TX 64 94 63 93 / 20 20 20 10
BIG SPRING TX 66 92 67 93 / 30 20 20 10
CARLSBAD NM 60 94 61 95 / 10 10 10 10
DRYDEN TX 66 90 67 94 / 20 20 20 20
FORT STOCKTON TX 65 94 65 96 / 20 20 20 10
GUADALUPE PASS TX 56 80 56 79 / 0 0 10 10
HOBBS NM 61 93 58 94 / 10 10 10 10
MARFA TX 57 87 56 86 / 20 10 10 10
MIDLAND INTL AIRPORT TX 66 92 66 94 / 20 20 20 10
ODESSA TX 66 93 66 94 / 20 20 20 10
WINK TX 64 97 63 98 / 10 10 10 10
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...RED FLAG WARNING FROM 10 AM TO 8 PM MDT TUESDAY FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS NP/LINCOLN NF/LNZ...
SOUTHEAST PLAINS/BLM ROSWELL/LNZ.
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES... GUADALUPE MOUNTAINS
NP/LINCOLN NF/LNZ...SOUTHEAST PLAINS/BLM ROSWELL/LNZ.
TX...RED FLAG WARNING FROM 10 AM TO 8 PM MDT TUESDAY FOR THE
FOLLOWING ZONES... GUADALUPE MOUNTAINS.
FIRE WEATHER WATCH FROM WEDNESDAY MORNING THROUGH WEDNESDAY
EVENING FOR THE FOLLOWING ZONES... GUADALUPE MOUNTAINS.
&&
$$
01/10
AREA FORECAST DISCUSSION...UPDATED
NWS LUBBOCK TX
1210 PM CDT MON APR 30 2012
.DISCUSSION...
FORECAST PARAMETERS ACROSS THE REGION ARE INDICATING THE POTENTIAL
FOR ANOTHER SEVERE WEATHER EVENT FOR THE FORECAST AREA LATE THIS
AFTERNOON THROUGH TONIGHT. 15Z SURFACE ANALYSIS SHOWS THAT GOOD
LOW-LEVEL MOISTURE REMAINS IN PLACE ACROSS THE REGION THIS MORNING
WITH SEVERAL WEAK OUTFLOW BOUNDARIES STILL IN THE AREA FROM THE
CONVECTION LAST NIGHT. LATEST VISIBLE SATELLITE LOOPS SHOWS WHERE
THE WESTERN EDGE OF THE BOUNDARIES ARE LOCATED...ROUGHLY ALONG A
MULESHOE...WOLLFORTH...TO SWEETWATER LINE. SOUTHWEST OF THIS
LINE...SUNNY SKIES AND LIGHT SOUTHWESTERLY WINDS ARE HELPING
DEWPOINTS TO SLOWLY MIX OUT WHILE NORTHEAST OF THIS LINE DEWPOINTS
ARE EXPECTED TO HOLD IN THE LOW 60S. 12KM NAM...13KM RUC...AND
THE 12/13/14Z HRRR RUNS DO NOT PICK UP ON THIS FEATURE BUT THE 3KM
TTU WRF DOES. WHERE THIS DRYLINE WILL SET UP WILL DETERMINE WHERE
THE BEST CHANCES FOR CONVECTION AND ALSO SEVERE WEATHER WILL BE.
THE TTU WRF PUSHES THE DRYLINE EAST OF THE I-27/US-87 CORRIDOR BY
THIS AFTERNOON/21Z AND THE 12KM NAM HAS SOME TYPE OF PUSH GETTING
CLOSE TO THE LUBBOCK AREA WHILE ALL THE OTHER MODEL RUNS HOLD IT
ACROSS THE WESTERN ROLLING PLAINS THROUGH THE DAY. ALL MODELS DO
HOWEVER GENERATE SOME FORM OF CONVECTION AS EARLY AS 21Z ACROSS
THE NORTHWESTERN SOUTH PLAINS. 500-METER MIXED LAYER CAPE VALUES ARE
PUSHING 2000-3000 J/KG EAST OF THE DRYLINE WITH SOME INDICATIONS
OF MAX CAPE VALUES PUSHING 4000 J/KG IN SEVERAL OF THE MODELS.
THERE IS A BIT OF A CAP THIS MORNING HOWEVER THIS IS WEAKENED
THROUGH THE DAY AND MAY BREAK AS EARLY AS 21Z...ESPECIALLY IF
THERE IS ANY LOCALIZED CONVERGENCE ALONG THE DRYLINE/OUTFLOW
BOUNDARIES. 0-6KM BULK SHEAR VALUES WILL BE SUFFICIENT TO SUPPORT
ORGANIZED CONVECTION ONCE AGAIN AND CANNOT RULE OUT SUPERCELLS
ESPECIALLY ACROSS THE EASTERN SOUTH PLAINS AND ALL OF THE ROLLING
PLAINS. LOW-LEVEL SHEAR LOOKS TO BE MARGINAL...HOWEVER ANY OUTFLOW
BOUNDARIES ACROSS THE AREA MAY PROVIDE SOME LOCALIZED ENHANCEMENT
SO THE TORNADO THREAT WILL BE NON-NEGLIGIBLE BUT STILL RATHER LOW.
HAVE GONE AHEAD AND INCREASED POPS ACROSS MOST OF THE AREA FOR
THIS AFTERNOON AND WILL CONTINUE MENTION OF SEVERE WEATHER...
PRIMARILY LARGE HAIL AND DAMAGING WINDS...FOR THIS AREA AS WELL.
HOWEVER...WILL MENTION ISOLATED TORNADOES IN THE HWO AS WELL.
BIGGEST UNCERTAINTY WILL ONCE AGAIN BE WHEN/WHERE STORMS WILL
FORM AND HOW LONG THEY WILL LAST. UPDATED GRIDS ARE OUT AND TEXT
PRODUCTS WILL BE UPDATED SHORTLY.
JORDAN
&&
.AVIATION...
MVFR TO VFR CEILINGS WILL GRADUALLY GIVE WAY TO VFR THIS AFTERNOON
AT BOTH TAF SITES. THERE IS A HIGH PROBABILITY THAT WE WILL SEE
THUNDERSTORMS IMPACT THE KLBB TERMINAL THIS AFTERNOON BUT WILL
NEED TO HOLD OFF MENTIONING AN EXACT TIME UNTIL WE CAN SEE HOW
SURFACE CONDITIONS EVOLVE. STORMS WILL LAST THROUGH THE EARLY
MORNING HOURS ONCE AGAIN AND COULD PRODUCE MVFR CEILINGS
OVERNIGHT. EXPECT TO SEE THESE CEILINGS IMPROVE THROUGH TOMORROW
AFTERNOON ACROSS THE AREA BACK INTO THE VFR RANGE.
JORDAN
&&
.PREV DISCUSSION... /ISSUED 640 AM CDT MON APR 30 2012/
AVIATION...
THANKS TO SOME WELCOME RAINFALL ACROSS THE SOUTH PLAINS...KLBB HAS
SEEN SOME LIGHT...WHAT LIMITED THREAT THERE IS FOR RESTRICTED
VISIBILITIES SHOULD WANE WITHIN THE NEXT HOUR OR TWO YIELDING VFR
CONDITIONS FOR BOTH TERMINALS MUCH OF THE DAY. THUNDERSTORMS WILL
ONCE AGAIN BE POSSIBLE...ESPECIALLY AT CHILDRESS THIS AFTERNOON AS
THE DRYLINE MARCHES EAST.
PREV DISCUSSION... /ISSUED 405 AM CDT MON APR 30 2012/
SHORT TERM...
LONG TERM....SHORT TERM...
MOST OF STORMS HAVE DIMINISHED THIS MORNING...LEAVING A WEAK SFC
BOUNDARY JUST TO THE NORTH OF THE FA. THERE REMAINS SOME POTENTIAL
FOR SHOWERS TO REDEVELOP ALONG THE BOUNDARY. BY 12Z...THE FEATURE
BEGINS TO WASH OUT...ALLOWING STORM DEVELOPMENT TO MAINLY BE ALONG
THE STATIONARY FRONT IN THE NRN TX PANHANDLE. STILL...GOOD LOW LVL
MOISTURE ACROSS THE AREA WILL CONTRIBUTE TO 2500 J/KG OF SBCAPE
ACROSS MOST OF THE FA. THROUGH MIDDAY...MOST OF THE FA WILL BE
FAIRLY CAPPED...WITH THE EXCEPTION OF THE NERN ZONES.
THEREFORE...WILL CONTINUE SLGT CHANCE THERE PRIOR TO 18Z. AFTER WARDS
THE DRYLINE BEGINS TO BULGE EASTWARD. THE NAM/TTUWRF BOTH INITIATE
STORMS ACROSS THE PANHANDLE AND PERMIAN BASIN EARLY IN THE
AFTERNOON...WITH DEVELOPMENT WORKING TOWARDS THE CENTER BY EARLY
EVENING. INITIATION LOOKS TO BE DUE TO A LOW AMPLITUDE SHORTWAVE
DISTURBING THE PREDOMINATELY ZONAL FLOW. ALONG THE DRYLINE THE
PRIMARY THREAT LOOKS TO BE WIND AS SOUNDING PROFILES SHOW A GOOD
INVERTED-V. EAST OF THE DRYLINE SHEAR INCREASES THROUGHOUT THE
AFTERNOON...WITH HELICITY AOA 200. GIVEN THE LIKELIHOOD OF ROTATING
UPDRAFTS HAVE ADDED T+ MENTION EAST OF THE DRYLINE.
MEADOWS
LONG TERM...
ATTENTION DURING THE EXTENDED IS ON THE DRYLINE SLOSHING ACROSS THE
FA THROUGHOUT THE WEEK AS WELL AS INCREASING SWRLY FLOW ALOFT DUE TO
THE SHORTWAVE TROF OFF THE ERN PACIFIC. GUIDANCE IS ONCE AGAIN
BRINGING THIS SHORTWAVE ACROSS NRN MEXICO BEFORE PUSHING THRU WTX.
HOWEVER...SPEED AND AMPLITUDE OF THIS SHORTWAVE REMAINS
QUESTIONABLE. THE GFS CONTINUES TO BE THE FASTEST WITH THIS SYSTEM
AND CONTINUES TO TREND TOWARDS MORE OF VERY LOW AMPLITUDE WAVE AS IT
CROSSES THE REGION. THE 12Z ECMWF SOLUTION PUSHES THE WAVE SLOW
ACROSS NRN MEXICO...ALLOWING IT TO BECOME IN PHASE WITH ANOTHER UL
TROF ACROSS THE PACIFIC NW. THIS ALLOWS THE UL RIDGE TO BUILD OVER
THE AREA. STILL...WILL CONTINUE THE SILENT POPS THRU THE PERIOD.
THE ONLY OTHER CONCERN WILL BE FIRE WX/WIND THREAT TUESDAY BEHIND
THE DRYLINE. POINT SOUNDINGS ACROSS THE WRN/CNTRL ZONES HAVE
INVERTED-V PROFILES. GUIDANCE HAS INCREASED THE MID LVL WINDS
SLIGHTLY...MOST LIKELY IN RESPONSE TO THE AFOREMENTIONED SHORTWAVE
INCREASING SWRLY FLOW. WILL HAVE TO CONSIDER A FIRE WX
WATCH...THOUGH MID LVL WINDS STILL LOOK TO BE ON THE LOW END.
MEADOWS
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 88 55 90 53 88 / 20 10 0 0 0
TULIA 89 59 92 57 91 / 40 20 10 10 0
PLAINVIEW 88 62 93 59 92 / 40 20 10 10 0
LEVELLAND 90 61 95 59 93 / 30 10 10 10 0
LUBBOCK 92 63 96 62 94 / 40 20 10 10 0
DENVER CITY 89 59 93 60 94 / 10 10 10 10 0
BROWNFIELD 89 62 96 60 95 / 30 10 10 10 0
CHILDRESS 83 62 93 64 95 / 40 30 10 10 10
SPUR 88 64 94 62 95 / 40 20 10 10 10
ASPERMONT 86 66 91 65 98 / 40 20 10 10 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
99/99/99
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
255 PM CDT MON APR 30 2012
.SHORT TERM...TONIGHT THROUGH THURSDAY NIGHT
255 PM CDT MON APR 30 2012
FORECAST FOCUS IS ON THE SHOWER AND THUNDERSTORM CHANCES FOR THE
NEXT COUPLE DAYS...WITH THE POTENTIAL FOR SEVERE WEATHER.
FOR THE FIRST PART OF TUESDAY...A WARM FRONT WILL BE HOVERING WEST
TO EAST...ROUGHLY FROM THE MID MISSISSIPPI RIVER VALLEY INTO
THE OH RIVER VALLEY. CONVECTION WILL FIRE AROUND THIS BOUNDARY. TO
THE NORTHWEST...AN UPPER LEVEL SHORTWAVE TROUGH WILL SPIN INTO MN.
THERE WILL LIKELY BE SOME SHOWERS AND THUNDERSTORMS ALREADY ONGOING
EARLY TUE MORNING ACROSS WESTERN/CENTRAL PARTS OF MN.
AS THE DAY WEARS ON...A 40 KT LOW LEVEL JET AND THE NOSE OF THE LOW
LEVEL MOISTURE TRANSPORT WILL FOCUS INTO CENTRAL
MN...ENHANCING/LEADING TO MORE SHOWER/STORM DEVELOPMENT. A COLD
FRONT WILL BE APPROACHING WESTERN WI BY 00Z WED. MUCAPES UPWARDS OF
2000+ J/KG ARE EXPECTED TO POOL AHEAD OF IT. ABOUT 30 TO 40 KTS OF
0-6 KM SHEAR WITH 20 TO 25 KTS IN THE 0-3 KM LAYER. NOT MUCH IF ANY
CAP INDICATED AHEAD OF THE FRONT BY THE MID-LATE AFTERNOON...AND
WOULD EXPECT SOME CONVECTION TO DEVELOP ALONG ITS SOUTHERN
FLANK...SOUTH OF THE MAIN CLUSTER OF STORMS ASSOCIATED WITH THE
SHORTWAVE. ENOUGH INSTABILITY AND WIND SHEAR TO SUPPORT A STRONG TO
SEVERE RISK. ELEVATED CAPE VALUES OVER 1500 J/KG PERSIST THROUGH THE
EVENING FOR THE FORECAST AREA...SO SOME INSTABILITY FOR ANY
STORM/LINE OF STORMS TO TAP INTO. PWS ARE PROGGED TO BE IN EXCESS OF
200%...ALTHOUGH WARM CLOUD DEPTH IS RELATIVELY LOW AT 3200 M. COULD
STILL SEE SOME HEAVY DOWNPOURS WITH ANY ACTIVITY. FOR TIMING...THE
SEVERE THREAT WOULD BE AFTER 00Z.
FOR MOST OF TUESDAY...THE SHORTWAVE AND LOW LEVEL WARM AIR ADVECTION
COULD PRODUCE SOME ISOLATED SHOWERS/STORMS...SO WILL CONTINUE THIS
MENTION IN THE FORECAST. WINDS WILL LIKELY BE THE BIGGER WEATHER
STORY LOCALLY DURING THE DAYTIME HOURS. A TIGHT SFC PRESSURE
GRADIENT DEVELOPS WHILE BUFKIT SOUNDINGS INDICATED AT MUCH AS 35 KTS
MIXING DOWN AT KRST. SOME OF THE WINDIER LOCATIONS WEST OF THE
MISSISSIPPI RIVER COULD FLIRT WITH WIND ADV CRITERIA LATE TUE
AFTERNOON/EARLY EVENING.
ON WED...THE WARM FRONT TO THE SOUTH WILL HAVE LIFTED NORTHWARD TO
ACROSS PARTS OF THE REGION. SOME DIFFERENCES ON WHERE THIS BOUNDARY
WILL LIE...AND THAT WILL HAVE A SIGNIFICANT IMPACT ON WHERE THE
BETTER RAIN CHANCES...AND SEVERE THREAT...WILL BE IN.
THE 30.12Z GFS FAVORS RESTING THE FRONT FROM SOUTHWEST MN INTO
NORTHERN WI BY 00Z...WHILE THE 30.12Z NAM HAS IT RESTING ACROSS
NORTHERN IA INTO SOUTHERN WI. THE GEM/EC MIMIC THE NAM. THE GFS HAS
BEEN CONSISTENT WITH ITS NORTHERN PLACEMENT...WHILE THE NAM HAS
TRENDED MORE SOUTH. WITH MORE SOLUTIONS FAVORING THIS SOUTHERN
PLACEMENT...WITH LEAN ON IT.
THE LOW LEVEL JET AND MOISTURE TRANSPORT WILL FOCUS INTO THE
BOUNDARY FOR WED AFTERNOON/EVENING WITH A GOOD AMOUNT OF
FRONTOGENETIC LIFT AROUND IT. MUCAPES AS MUCH AS 2500 J/KG WITH
0-6 KM SHEAR VALUES NEAR 50 KTS IN THE VICINITY OF THE WARM FRONT.
SOME UNCERTAINTY TO WHETHER ALL THIS INSTABILITY WILL BE REALIZED AS
THE ATMOSPHERE COULD BE MUCKED OVER FROM OVERNIGHT CONVECTION AND
BLOW OFF FROM STORMS ELSEWHERE. HOW QUICKLY...AND IF THE ATMOSPHERE
CAN RELOAD LOCALLY IS IN QUESTION. IF IT CAN THOUGH...THERE WILL BE
A STRONG TO SEVERE THUNDERSTORM RISK. IN ADDITION...WITH THE WARM
FRONT AND LIKELY OTHER BOUNDARIES WAVERING ACROSS THE REGION...THERE
WOULD BE AN ISOLATED TORNADO THREAT.
IT SHOULD ALSO BE NOTED THAT TRAINING STORMS APPEAR LIKELY...RUNNING
ALONG THE WARM FRONT. WITH PWS STILL WELL ABOVE 200 PERCENT OF
NORMAL AND WARM CLOUD DEPTHS INCREASING TO ABOVE 3500 M...LOCALIZED
HEAVY RAIN APPEARS LIKELY.
SO...THERE WILL BE A THREAT FOR SEVERE WEATHER OVER THE NEXT COUPLE
DAYS...WITH SEVERAL CAVEATS ATTACHED TO THE RISK. SHORT TERM
CONDITIONS WILL HAVE TO BE MONITORED CLOSELY.
.LONG TERM...FRIDAY THROUGH MONDAY
255 PM CDT MON APR 30 2012
THE GFS AND ECMWF CONTINUE TO PAINT A CONTINUATION OF THE ACTIVE
WEATHER PATTERN THROUGH THE WEEKEND...WITH VARIOUS BITS OF UPPER
LEVEL ENERGY BRINGING PERIODIC SHOWER/STORM CHANCES. WHILE TIMING IS
SUBJECTIVE AT THIS MOMENT...BOTH THE GFS/EC FAVOR SUNDAY AS A WET
DAY. THE REGION WILL ALSO STAY UNDER THE INFLUENCE OF SOME BROAD
RIDGING...WHICH WILL KEEP TEMPERATURES ABOVE NORMAL THROUGH AT LEAST
SATURDAY. WITH THE PATTERN SOMEWHAT MESSY...CONFIDENCE IN TIMING ON
ANY PARTICULAR FEATURE IS NOT HIGH...SO WILL STAY WITH CONSENSUS
SOLUTION FOR NOW.
&&
.AVIATION...THROUGH 18Z TUESDAY
1259 PM CDT MON APR 30 2012
THE VISIBLE SATELLITE LOOP SHOWS THAT THE CLOUDS ARE STARTING TO
BECOME OPEN CELLULAR. THE SOUNDINGS CONTINUE TO SUGGEST THAT THE
DEPTH OF THE MOISTURE WILL SLOWLY SHRINK THIS AFTERNOON...AND THAT
MANY AREAS WILL SEE A RAPID INCREASE IN THE SUNSHINE BETWEEN 30.20Z
AND 30.23Z. AS A RESULT...KEPT THAT TREND GOING AT KRST AND KLSE
TAFS.
FOR LATE TONIGHT AND TUESDAY MORNING...THE MAIN QUESTION IS
WHETHER FOG WILL DEVELOP. THE NAM/WRF WOULD SUGGEST THAT THERE
WILL BE FOG AND IFR CEILINGS WEST OF THE MISSISSIPPI RIVER.
MEANWHILE THE GFS AND RUC CONTINUE TO SUGGEST THAT THIS LOW LEVEL
MOISTURE WOULD BE FURTHER WEST. THIS IS HIGHLY DEPENDENT UPON THE
SPEED OF THE SYSTEM MOVING OUT OF THE INTERMOUNTAIN REGION. THE
NAM/WRF SEEMS TO BE JUST A BIT TOO FAST...SO LEANED MORE TOWARD
THE SLOWER GFS AND KEPT THE LOW CLOUDS AND FOG OUT OF THE FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
255 PM CDT MON APR 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....RIECK
AVIATION.....BOYNE
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
100 PM CDT MON APR 30 2012
.SHORT TERM...THIS MORNING
902 AM CDT MON APR 30 2012
VISIBILITIES ACROSS NORTHEAST IOWA AND SOUTHWEST WISCONSIN HAVE
IMPROVED TO 3 MILES OR HIGHER. DUE TO THIS...THE DENSE FOG
ADVISORY HAS BEEN CANCELLED EARLY.
.LONG TERM...THURSDAY THROUGH SUNDAY
351 AM CDT MON APR 30 2012
AN UNSETTLED PATTERN WILL PERSIST ACROSS THE AREA THROUGH THE END
OF THE WORK WEEK AND INTO THE WEEKEND. EMBEDDED SHORTWAVES IN
SOUTHWEST FLOW ALOFT WILL BRING DAILY CHANCES FOR SHOWERS AND
THUNDERSTORMS. HIGH TEMPERATURES ARE EXPECTED TO REMAIN IN THE 70S
THROUGH SATURDAY...BEFORE A FRONTAL BOUNDARY SLIPS THROUGH THE
REGION SATURDAY NIGHT INTO SUNDAY. SEVERE THUNDERSTORMS REMAIN A
POSSIBILITY THURSDAY THROUGH SATURDAY NIGHT WITH SUFFICIENT SHEAR
AND CAPE IN PLACE. EXACT DETAILS ARE DIFFICULT TO NAIL DOWN THIS
FAR OUT...BUT WILL HAVE TO KEEP A CLOSE WATCH ON THIS. HIGHS ARE
EXPECTED TO FALL INTO THE 60S ON SUNDAY. OVERNIGHT LOWS THROUGH
THE PERIOD WILL RANGE FROM THE MID TO LOWER 50S ACROSS NORTH
CENTRAL WISCONSIN TO AROUND 60 ACROSS NORTHEAST IOWA INTO FAR
SOUTHWEST WISCONSIN.
&&
.AVIATION...THROUGH 18Z TUESDAY
1259 PM CDT MON APR 30 2012
THE VISIBLE SATELLITE LOOP SHOWS THAT THE CLOUDS ARE STARTING TO
BECOME OPEN CELLULAR. THE SOUNDINGS CONTINUE TO SUGGEST THAT THE
DEPTH OF THE MOISTURE WILL SLOWLY SHRINK THIS AFTERNOON...AND THAT
MANY AREAS WILL SEE A RAPID INCREASE IN THE SUNSHINE BETWEEN 30.20Z
AND 30.23Z. AS A RESULT...KEPT THAT TREND GOING AT KRST AND KLSE
TAFS.
FOR LATE TONIGHT AND TUESDAY MORNING...THE MAIN QUESTION IS
WHETHER FOG WILL DEVELOP. THE NAM/WRF WOULD SUGGEST THAT THERE
WILL BE FOG AND IFR CEILINGS WEST OF THE MISSISSIPPI RIVER.
MEANWHILE THE GFS AND RUC CONTINUE TO SUGGEST THAT THIS LOW LEVEL
MOISTURE WOULD BE FURTHER WEST. THIS IS HIGHLY DEPENDENT UPON THE
SPEED OF THE SYSTEM MOVING OUT OF THE INTERMOUNTAIN REGION. THE
NAM/WRF SEEMS TO BE JUST A BIT TOO FAST...SO LEANED MORE TOWARD
THE SLOWER GFS AND KEPT THE LOW CLOUDS AND FOG OUT OF THE FORECAST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
901 AM CDT MON APR 30 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...WETENKAMP
AVIATION...BOYNE
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
1202 PM CDT MON APR 30 2012
.UPDATE...FOG HAS DISSIPATED ACROSS THE AREA...AS DAYTIME HEATING
ALLOWED FOR ENOUGH MIXING IN THE LOW LEVELS. LOW CLOUDS CONTINUE
TO LINGER ACROSS THE REGION AS WELL. LATEST RUC FORECAST SOUNDINGS
SHOWING EASTERN PORTIONS OF THE AREA REMAINING UNDER THESE CLOUDS
THROUGH THE REST OF THE DAY...WITH SOME MIXING POSSIBLE IN THE
WESTERN COUNTIES BY LATER THIS AFTERNOON. BACK EDGE OF THESE
CLOUDS EXTEND FROM NORTHWEST WISCONSIN TO CENTRAL IOWA AT THIS
TIME...AND ARE QUITE SLOW TO SHIFT EAST.
FOR THE REST OF THE DAY...WILL GO WITH MOSTLY CLOUDY SKIES...WITH
SOME BREAKS IN THE WEST LATE IN THE DAY. CLOUDS WILL KEEP HIGHS
DOWN FROM CURRENT LEVELS...SO WILL HAVE TO ADJUST THEM DOWN INTO
THE 50S ACROSS MOST OF THE AREA.
IF CLOUDS DO NOT MIX OUT BY SUNSET...THEY MAY STICK AROUND THROUGH
TONIGHT UNDER INVERSION. CONFIDENCE IS MEDIUM AT THE MOMENT WITH
THIS HAPPENING...BUT THE POTENTIAL IS THERE.
&&
.AVIATION/18Z TAFS/...
MVFR/IFR CEILINGS ACROSS TAF SITES SHOULD BECOME MAINLY MVFR
DURING THE AFTERNOON. BREAKS ACROSS THE EASTERN SITES SHOULD BE
SHORT LIVED...WITH OVERCAST MVFR DECK MOVING BACK INTO THE AREA
WITHIN AN HOUR OR TWO. LIGHT AND VARIABLE WINDS WILL BECOME LIGHT
OUT OF THE WEST THIS AFTERNOON...WITH LIGHT SOUTHEAST WINDS LATER
THIS AFTERNOON AT MILWAUKEE AND KENOSHA WITH LAKE BREEZE.
IF CURRENT MVFR CLOUD DECK DOES NOT MIX OUT BY SUNSET ACROSS TAF
SITES...EXPECT THEM TO LINGER THROUGH TONIGHT INTO TUESDAY
MORNING. CONFIDENCE IS MEDIUM IN THIS OCCURRING...BUT POTENTIAL IS
CERTAINLY THERE. IF THE CLOUDS LINGER...IFR/LIFR CEILINGS WOULD
BE POSSIBLE AT TIMES AS WELL...GIVEN THE LIGHT WINDS AND LACK OF
ANY MIXING IN THE LOW LEVELS. MVFR/IFR FOG WOULD BE POSSIBLE AS
WELL...THOUGH DENSE FOG IS NOT ANTICIPATED DUE TO THE CLOUDS.
THESE CONDITIONS WOULD NOT IMPROVE TO VFR UNTIL LATER TUESDAY
MORNING OR EARLY TUESDAY AFTERNOON. SOUTHEAST WINDS WILL INCREASE
THROUGH THE REST OF THE DAY...WITH MIDDLE TO HIGH CLOUDS MOVING
INTO THE AREA. ANY PRECIPITATION SHOULD HOLD OFF UNTIL AFTER 00Z
WEDNESDAY ACROSS TAF SITES.
&&
.PREV DISCUSSION... /ISSUED 343 AM CDT MON APR 30 2012/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE - LOW TO MEDIUM.
LIGHT WINDS ASSOCIATED WITH WEAK SURFACE TROUGH AND LOW LEVEL
MOISTURE RESULTING IN DENSE FOG OVER ERN IA WHICH IS SPREADING
NORTHEAST INTO FOGGY SUSCEPTIBLE AREAS OF SW CWA. WL HOIST DENSE
FOG ADVY FOR MY FAR SOUTHWEST...WITH THE POTENTIAL FOR DENSE FOG
SPREADING EAST TOWARD RACINE AND KENOSHA EARLY THIS MRNG AS THE
WEAKEST PRESSURE GRADIENT AND LIGHTEST WINDS SPREAD EWD. HRRR ALSO
SHOWING AREAS OF DENSE FOG IN MY FAR SOUTH THRU EARLY MRNG.
ENHANCED SYNOPTIC SCALE FORCING AND LAYER Q-VECTOR CONVERGENCE WILL
CONTINUE TO PUSH TO THE EAST OF SRN WI BY EARLY THIS MRNG ENDING
MOST OF THE -SHRA...HOWEVER FEW -SHRA COULD CLIP THE FAR SOUTHEAST
UNTIL LATER THIS MRNG. SECONDARY WEAK SHORT WAVE UPSTREAM OVER WRN
IA MAY GENERATE SOME PATCHY DRIZZLE AS WELL IN LINGERING LOW LEVEL
RH THIS MRNG. LOW LEVEL WINDS SWITCHING TO THE WEST THIS MRNG WL
ALLOW DRIER AIR ABV INVERSION TO PUSH INTO SRN WI...HOWEVER SHORT
TERM GUIDANCE MAY BE UNDERDOING AMOUNT OF UPSTREAM MOISTURE. KOAX
00Z SOUNDING HAD MOISTURE EXTENDING TO 5K FT. SO THINKING CLOUDS
COULD LINGER FOR MUCH OF THE AFTN...ESPECIALLY IN THE EAST...HOWEVER
CONFIDENCE LOW AT THIS POINT. IF BREAKS WERE TO OCCUR...THEN GOING
TMAX FOR TODAY WL BE TOO LOW.
LOW LEVEL MOISTURE WL LINGER INTO TNGT WITH LIGHT SFC WNDS
CONTINUING. WEAK UPSTREAM WARM AIR ADVECTION WL LIKELY BRING SOME
PATCHY MID-HIGH CLOUDS OVER THE AREA...BUT AT THIS POINT LEANING
TOWARD CLOUD COVER REMAINING SCT-BKN. THIS WOULD ALLOW MORE FOG TO
DEVELOP LATER TNGT.
TUESDAY AND TUESDAY NIGHT...FORECAST CONFIDENCE MEDIUM.
RAIN WILL BE A LITTLE SLOW TO RETURN TO SOUTHERN WI ON TUE GIVEN THE
WEAK RIDGING IN PLACE AND MID LEVEL DRY AIR. MODEL SOUNDINGS SHOW
LIMITED CAPE WITH THE INITIAL PRECIP SO ONLY MENTIONED ISOLATED
THUNDER IN THE FAR SOUTH IN THE AFTERNOON. THE BEST FORCING WILL BE
OVER MN AND CENTRAL IL WHERE THERE IS MORE SHORTWAVE ACTIVITY AND
THE NOSE OF THE LOW LEVEL JET /LLJ/. THE BETTER DYNAMICS FOR
THUNDERSTORM DEVELOPMENT IS EXPECTED TO MOVE ACROSS CENTRAL WI TUE
NIGHT...ESPECIALLY AFTER MIDNIGHT. SUSPECT A MESOSCALE CONVECTIVE
SYSTEM TO DEVELOP UPSTREAM WITH THE NOSE OF THE LLJ AND UPPER
DIVERGENCE DUE TO A COUPLED UPPER JET OVER CENTRAL WI. MAIN THREAT
FOR TUE NIGHT WOULD BE HAIL IN THE ELEVATED CONVECTION. KEPT LIKELY
POPS IN THE NORTHWEST FORECAST AREA AND CHANCE ELSEWHERE.
WEDNESDAY THROUGH THURSDAY...FORECAST CONFIDENCE MEDIUM.
THE SEVERE POTENTIAL IS STILL THERE FOR THIS TIME PERIOD...BUT IT
LOOKS MOST LIKELY AROUND 00Z THU WHEN THE NOSE OF THE LLJ POINTS
INTO SOUTHERN WI AND RIGHT ENTRANCE REGION OF THE UPPER JET BRINGS
THE DEEPER LIFT. A SHORTWAVE IS ALSO PROGGED TO REACH SOUTHERN WI
AROUND THIS TIME AS WELL...WITH THE ECMWF A LITTLE EARLIER THAN THE
GFS. THE FEAR IS THAT WE MAY NOT GET A GOOD ENOUGH TRIGGER FOR
THUNDERSTORMS ANY EARLIER THAN LATE WED AFTERNOON...SO TRIED TO BACK
OFF ON POPS FOR WED. HOWEVER THERE COULD BE SOMETHING TRIGGERING
ALONG ANY OUTFLOW BOUNDARIES FROM PREVIOUS CONVECTION TUE NIGHT.
CAPE VALUES WILL BE HIGH WED AFTERNOON BUT THE BETTER SHEAR FOR
ORGANIZED STORM DEVELOPMENT WILL NOT ARRIVE UNTIL THE LLJ MOVES IN.
HAIL AND WIND WOULD BE THE MAIN THREATS.
SOUTHERN WI WILL REMAIN IN THAT WARM AND UNSTABLE AIR MASS THROUGH
THURSDAY AND ADDITIONAL SHORTWAVES TRACKING ALONG THE WEAKLY
CYCLONIC 500MB FLOW COULD BRING MORE ROUNDS OF SHOWERS AND
THUNDERSTORMS TO SOUTHERN WI WED NIGHT AND THU.
THE SEVERE WEATHER PARAMETER PRODUCT /CWASP/ IN OUR OFFICE
CONTINUES TO SHOW PORTIONS OF SOUTHERN WI IN THE 60 TO 70 PERCENT
RANGE FOR SEVERE WEATHER FOR 00Z THU AND AGAIN 00Z FRI.
TEMPERATURES WILL BE WARM WITH 925MB TEMPS AROUND 19 TO 20C AND
INTERMITTENT DEEPER MIXING EXPECTED TO REACH THAT LEVEL OR HIGHER.
LONG TERM...
THURSDAY NIGHT THROUGH SATURDAY...FORECAST CONFIDENCE MEDIUM.
THE 850MB BAROCLINIC ZONE WILL REMAIN NEARLY STATIONARY OVER
SOUTHERN WI/NORTHERN IL THROUGH AT LEAST SATURDAY AND THEN SLIP
SOUTHWARD. THE ECMWF IS FASTER WITH THAT IDEA. SHOWER AND
THUNDERSTORM CHANCES WILL CONTINUE ALONG THE BAROCLINIC ZONE IN
SOUTHERN WI...TIED TO THE CONTINUOUS STREAM OF 500MB SHORTWAVES.
THERE WILL BE BREAKS BETWEEN WEATHER SYSTEMS AND POSSIBLY SOME
SUNSHINE AS WELL. TEMPS WILL CONTINUE TO RISE INTO THE 70S THROUGH
SATURDAY.
SUNDAY THROUGH MONDAY...FORECAST CONFIDENCE MEDIUM TO LOW.
500MB RIDGE AMPLIFYING ACROSS CENTRAL U.S. WILL KEEP THE FOCUS OF
ITS SHORTWAVE ENERGY OVER SOUTHERN WI...THEN SLOWLY SINK SOUTHWARD
WITH THE BAROCLINIC ZONE TOWARD MONDAY AND EARLY NEXT WEEK.
CHANCES FOR SHOWERS WILL CONTINUE.
AVIATION/12Z TAFS/...LOW CIGS AND VSBYS THIS MRNG WITH POTENTIAL
FOR FOG DROPPING VSBYS BLO 1SM FOR A TIME. AS LOW LEVEL FLOW ABV
INVERSION TURNS TO THE WEST AND INCREASES...LOW LEVEL MIXING OF
DRIER AIR SHOULD GRADUALLY LIFT CIGS TO VFR THIS AFTN OR EVE. LOW
LEVEL MOISTURE TO LINGER INTO TNGT HOWEVER WHICH SHOULD RESULT IN AT
LEAST PATCHY FOG...BUT WL DEPEND ON AMOUNT OF MID/HIGH CLOUDS OVER
AREA AS WARM AIR ADVECTION RECOMMENCES UPSTREAM.
MARINE...AS EXPECTED HAD A FEW GUSTS INTO THE LOWER 20S OVERNIGHT
AS PRESSURE GRADIENT BRIEFLY TIGHTENED DUE TO WEAK LOW PRESSURE
MOVING THRU CENTRAL MS VALLEY. PRESSURE GRADIENT ALREADY WEAKENING
IN RESPONSE TO SFC LOW APPROACHING ERN IL WITH WEAK NORTHWARD SFC
TROUGH EXTENSION. WINDS WL DMSH TO LIGHT AND VARIABLE FOR MUCH OF
THE DAY INTO TNGT. EXPC AREAS OF FOG THIS MRNG. WL NEED TO WATCH
WEBCAMS FOR POTENTIAL PERIOD OF VSBYS OF 1NM OR LESS IN DECREASING
LOW LEVEL WINDS AND MOIST LOW LEVELS.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...WOOD
TODAY/TONIGHT AND AVIATION/MARINE...MBK
TUESDAY THROUGH SUNDAY...MRC