Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 05/02/12
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 ALBANY NY
744 PM EDT TUE MAY 1 2012
.SYNOPSIS...
A WEAK DOME OF HIGH PRESSURE WILL MOVE ACROSS THE REGION TONIGHT.
HOWEVER...CHANGES ARE ON THE WAY AS WARMER AIR ATTEMPTS TO BUILD
FROM THE SOUTHERN PORTIONS OF THE COUNTRY. ALONG WITH THAT
CHANGE...THERE WILL A CHANCE FOR SHOWERS AND THUNDERSTORMS FOR THE
SECOND HALF OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 7 PM...MOSTLY CLOUDY TO CLOUDY CONDITIONS ALONG WITH POCKETS
OF DRIZZLE PREVAILED ACROSS THE NORTHERN TWO THIRDS OF THE FA WITH
PARTLY CLOUDY TO MAINLY CLEAR CONDITIONS ACROSS THE SOUTHERN TWO
THIRDS OF THE FA. TEMPS WERE MILDER THAN THEY HAVE BEEN DURING
RECENT DAYS AT THIS TIME WITH READINGS GENERALLY IN THE 50S TO
MID 60S.
EXPECTATION IS FOR THE STRATUS DECK TO BECOME RE-ESTABLISHED
TONIGHT AS THE COMBINATION OF A MOIST GROUND AND BOUNDARY LAYER
COOLING FOR CONDENSATION TO OCCUR. IN FACT...SFC DEWPOINT
DEPRESSIONS ARE EXPECTED TO NARROW ALONG WITH APPLICATIONS OF THE
CROSS OVER TECHNIQUE AND LOWERING THE MRI IN THE LOWEST 100MB /PER
BUFKIT/ TO RESULT IN PATCHY/AREAS OF FOG AS WELL AS SOME DRIZZLE
THIS EVENING.
MORE OF AN INTEREST IS THE WELL DEFINED MCV TRACKING NORTHEAST
ACROSS IL/IN. NCEP MODEL SUITE NOT PERFORMING TOO WELL WITH THIS
FEATURE AS WE REFERRED TO THE NAM ARW CORE AND HOURLY RAPID REFRESH
/REPLACED THE RUC THIS MORNING/. THE ANALYSIS OF THESE MODELS
SUGGESTS THIS MCV SHOULD WEAKEN AS IT APPROACHES THE ANTICYCLONIC
FLOW ACROSS PA/NY. HOWEVER...IT MAY SURVIVE JUST ENOUGH TO WARRANT
THE CHANCE OF POPS SOUTH OF I90 OVERNIGHT. IN ADDITION...THE
THERMAL WIND FORECASTS FROM 850-300MB SUGGEST A MORE EASTWARD
PROGRESSION TO FURTHER SUPPORT THE CHANCE POPS. OVERNIGHT LOWS
WILL DROP BACK MAINLY INTO THE 40S CWA-WIDE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
A VERY CHALLENGING FORECAST PERIOD WITH LOW CONFIDENCE APPROACH.
CONVECTIVE UPSTREAM TRENDS WILL ULTIMATELY DICTATE THE SYNOPTIC
AND MESOSCALE INFLUENCES AS SPRING ATTEMPTS TO MAKE A STRONG PUSH
INTO THE REGION.
WHAT WE CAN DECIPHER FROM THE NCEP MODEL SUITE AND INTERNATIONAL
GUIDANCE ARE A TREND TOWARD INCREASING HEIGHTS WITH WARMER
TEMPERATURES AND INCREASING AMOUNTS OF MOISTURE. THE CHANCE FOR
SHOWERS WILL EXPAND ACROSS THE REGION WEDNESDAY AS THE NEXT SURGE
OF WARM ADVECTION AND THETA-E ADVECTION APPROACH. MID LEVEL
INSTABILITY REMAINS RATHER POSITIVE /SHOWALTER VALUES INTO THE
SINGLE DIGIT TERRITORY/ TO WITHHOLD THE MENTION OF THUNDER AT THIS
TIME. HOWEVER...THAT IS EXPECTED TO GRADUALLY CHANGE WEDNESDAY
NIGHT INTO THURSDAY NIGHT WHERE WE WILL INTRODUCE THE CHANCE FOR
THUNDERSTORMS.
MOS NUMBERS DO SUPPORT THE INCREASING THERMAL PROFILES BUT CLOUD
COVER REMAINS A CHALLENGE. AT THIS POINT...WE WILL CONTINUE TO
FAVOR ON THE COOLER SIDE OF THE GUIDANCE ENVELOPE.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
THE EARLY PORTION OF THE LONG TERM FORECAST IS UNCERTAIN WITH
WIDE POSSIBLE RANGES IN TEMPS AND POPS. DESPITE BUILDING HEIGHTS
ALOFT INTO FRIDAY...THE WEATHER AT THE SURFACE LOOKS RATHER
NEBULOUS. LATEST GUIDANCE TRENDS FROM THE NAM AND GGEM INDICATE A
POSSIBLE NEARLY STATIONARY FRONTAL BOUNDARY DRAPED OVER THE AREA
WITH WEAK WAVES OF LOW PRESSURE MOVING ALONG THE BOUNDARY. THIS
WOULD RESULT IN A COOLER AND CLOUDIER FORECAST FOR FRIDAY.
HOWEVER...THE GFS CONTINUES TO INDICATE OUR REGION WILL BE IN A
WARM SECTOR AHEAD OF A PRE-FRONTAL TROUGH AND COLD FRONT ATTACHED
TO A STRONGER LOW DROPPING SOUTHEASTWARD THROUGH QUEBEC. THIS
SOLUTION WOULD IMPLY MUCH WARMER TEMPS...MORE IN THE WAY OF
SUNSHINE AND ALSO BETTER CHANCES FOR POTENTIALLY STRONG
CONVECTION. BASED ON THE GFS BEING AN OUTLIER AT THIS POINT...WILL
SIDE WITH THE NAM/GGEM AND ECMWF SOLUTION WITH A COOLER AND
CLOUDIER DAY FOR FRIDAY. STILL RELATIVE TO NORMAL IT WILL BE
WARM...BUT WILL FORECAST TEMPS A GOOD 10 DEGREES COOLER THAN THE
GFS MEX GUIDANCE. THIS COULD END UP CHANGING AS THE WEEK
PROGRESSES.
WHICH EVER TYPE OF SYSTEM AFFECTS THE REGION ON FRIDAY...THERE IS AT
LEAST LOOSE CONSENSUS FOR A NORTHERN STREAM TROUGH TO DIG
SOUTHWARD INTO EASTERN CANADA FRIDAY NIGHT INTO SATURDAY...WHICH
WOULD PUSH THROUGH EITHER THE WEAK WAVE/STATIONARY FRONT OR A
STRONGER CYCLONE. WILL MENTION CHANCE POPS FOR FRIDAY NIGHT INTO
SATURDAY WITH TEMPS STILL REMAINING WARM. DRYING APPEARS POSSIBLE
FOR LATE SATURDAY NIGHT INTO SUNDAY...BUT A LOT DEPENDS ON HOW THE
PATTERN EVOLVES PRIOR TO THE WEEKEND.
WILL MENTION DRY WEATHER AND NEAR NORMAL TEMPS THROUGH EARLY NEXT
WEEK WITH A DRY NORTHERLY FLOW OVER THE AREA DEPICTED BY MOST OF THE
MEDIUM RANGE GUIDANCE.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
OVERNIGHT EXPECT MAINLY MVFR CONDITIONS AT THE TAF SITES EXCEPT
MVFR CONDITIONS GIVING WAY TO IFR CONDITIONS AT KGFL. THE
COMBINATION OF A STRATUS DECK...NARROW T/TD RANGE AND A MOIST
SURFACE IN MUCH OF THE HUDSON VALLEY WILL ALSO RESULT IN AREAS OF
FOG AND SOME DRIZZLE THIS EVENING ESPCLY AT KALB. ON WEDNESDAY
CIGS AND VSBYS ARE EXPECTED TO BECOME VFR FAIRLY EARLY IN THE
DAY...HOWEVER OVC CONDITIONS WILL PERSIST MUCH OF THE DAY AS A
WARM FRONT ONLY SLOWLY LIFTING NORTHEAST FROM THE EASTERN GREAT
LAKES WEDNESDAY AFTERNOON INTO WESTERN NEW YORK WEDNESDAY EVENING.
WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE OR CALM AT THE TAF
SITES OVERNIGHT AND THEN BECOME SOUTHEAST AT 4-5 KTS WEDNESDAY
MORNING AND SOUTH AT 4-8 KTS WEDNESDAY AFTERNOON.
.OUTLOOK...
WED NIGHT-THU...MAINLY VFR...CHC -SHRA.
THU NIGHT-SAT...MAINLY VFR. CHC -SHRA OR -TSRA.
SUN...VFR...NO SIG WX.
&&
.FIRE WEATHER...
MINIMAL FIRE WEATHER CONCERNS AS PRECEDING RAINFALL WAS BENEFICIAL
FOR THE REGION. AS THE COMBINATION OF INCREASING MOISTURE AND
COMPETING CLOUD COVER WILL MAKE FOR ELEVATED RELATIVE HUMIDITIES
AND MINIMAL VALUES ON THE HAINES INDEX FOR THE BALANCE OF THE
WEEK.
&&
.HYDROLOGY...
NO HYDRO PROBLEMS ARE EXPECTED THIS WEEK. WHILE CONFIDENCE IN THE
OVERALL EXPECTATIONS OF CONVECTIVE ACTIVITY ARE LOW...WITH LAKE AND
RIVER LEVELS REMAINING QUITE LOW...QPFS ARE EXPECTED TO REMAIN AT
OR BELOW 1 INCH PER THE BASIN AVERAGE.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM/11
SHORT TERM...BGM
LONG TERM...JPV
AVIATION...11
FIRE WEATHER...BGM
HYDROLOGY...BGM
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 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 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
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 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 CHICAGO/ROMEOVILLE IL
1011 PM CDT TUE MAY 1 2012
.DISCUSSION...
935 PM CDT
SURFACE QUASI-WARM FRONT WAS ANALYZED ALONG THE SOUTHERN PERIPHERY
OF THE WFO LOT CWA THIS EVENING...HAVING BEEN SUPPRESSED BY
WELL-DEFINED MID-LEVEL VORT AND ASSOCIATED SURFACE WAVE THIS
AFTERNOON. EVENING WATER VAPOR IMAGERY INDICATES THIS MID-LEVEL
CIRCULATION IS NOW OVER INDIANA AND SOUTHERN LOWER MICHIGAN AND
MOVING AWAY FROM THE CWA...WITH THE AREA OF RAIN ASSOCIATED WITH
THIS FEATURE ALSO WEAKENING AND MOVING OUT OF THE AREA AT THIS TIME
WITH ONLY A FEW WEAK RADAR RETURNS LINGERING OVER FAR SOUTHERN LAKE
MICHIGAN AND PARTS OF THE EAST/SOUTHEAST CHICAGO METRO COUNTIES.
HAVE ADJUSTED POPS/WX GRIDS ACCORDINGLY...WITH LITTLE POTENTIAL FOR
ORGANIZED PRECIP ANTICIPATED THROUGH AT LEAST MIDNIGHT IN SUBSIDENT
WAKE OF DEPARTING MID-LEVEL VORT.
THE WARM FRONT IS STILL PROGGED TO LIFT NORTH OVERNIGHT...AND THEN
NORTH OF THE FORECAST AREA WEDNESDAY MORNING. SEVERAL FORECAST
CHALLENGES REMAIN FOR THE OVERNIGHT PERIOD HOWEVER...INCLUDING
STEADY/RISING TEMPERATURES WITH WARM FRONT...DEVELOPMENT OF PATCHY
DENSE FOG...AND THE POTENTIAL FOR RENEWED SHOWER AND THUNDERSTORM
DEVELOPMENT DURING THE LATE NIGHT HOURS.
GOES 11-3.9 MICRON IR IMAGERY INDICATES LOW STRATUS IN EASTERLY
LOW-LEVEL FLOW NORTH OF THE SURFACE WARM FRONT AT 02Z...WITH A FEW
NORTHERN IL LOCATIONS SUCH AS VYS DEVELOPING PATCHY DENSE FOG WHERE
SOME BREAKS HAVE FORMED ALONG THE SOUTHERN EDGE OF THE STRATUS DECK.
FARTHER NORTH...A SLOW LOWERING TREND HAS BEEN NOTED IN VISIBILITY
WITH AREAS OF 1-3SM FOG EXPECTED TO PERSIST DURING THE NIGHT WITH
IMPROVEMENT LIKELY FROM THE SOUTH AS WARM SECTOR SPREADS NORTH.
TEMPERATURES HAVE FALLEN INTO THE LOW/MID 50S ALONG THE LAKE
MICHIGAN SHORE...AND WILL LIKELY DIP TO THE UPPER 50S/AROUND 60
ELSEWHERE NORTH OF THE WARM FRONT AND INTO THE LOWER 60S FARTHER
SOUTH. TEMPERATURES WILL THEN LIKELY BECOME STEADY...AND EVEN RISE
LATE TONIGHT HOWEVER AS THE FRONT LIFTS NORTH.
AS FOR PRECIPITATION TRENDS...EXPECT SEVERAL HOURS OF DRY WEATHER AS
MENTIONED ABOVE. EVENING UPPER AIR ANALYSIS DOES INDICATE A 40 KT
MID-LEVEL SPEED MAX UPSTREAM OVER KANSAS THAT IS PROGGED TO
TRANSLATE NORTHEAST OVERNIGHT ALONG WITH A VERY MOIST WARM SECTOR
AIRMASS WITH H9 DEWPOINTS OF 16C NOTED UPSTREAM. SEVERAL RECENT RUNS
OF THE HRRR HAVE DEPICTED ELEVATED CONVECTION DEVELOPING ACROSS
SOUTHEAST IOWA AND MISSOURI THIS EVENING ALONG THE WARM FRONTAL ZONE
AND SPREADING INTO IL BY MIDNIGHT...AND WHILE DEEP MOIST CONVERGENCE
IS ANALYZED ALONG THE FRONT...SATELLITE AND RADAR TRENDS SUGGEST
THIS APPEARS TO BE OVER-FORECAST. A MORE LIKELY SCENARIO IS FOR MCS
OVER FAR SOUTHWESTERN MINNESOTA AND NORTHWEST IOWA TO PROPAGATE
EAST-SOUTHEAST ALONG THE FRONTAL ZONE AND EVENTUALLY WEAKEN AS IT
MOVES INTO THE FORECAST AREA DURING THE PRE-DAWN HOURS OF EARLY
WEDNESDAY.
RATZER
//PREV DISCUSSION...
304 PM CDT
CONCERNS FOR LATEST FORECAST PACKAGE WILL BE DEALING WITH ONGOING
CONVECTIVE CHANCES THROUGH THE WEEK...AS WELL AS IMPACT ON
TEMPERATURES.
TODAY...WELL DEFINED MCV FROM REMNANT MCC MOVING ACROSS CENTRAL
ILLINOIS WITH LINGERING SHOWERS ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA. THIS AFTERNOON...VERY MODEST MUCAPE (LESS THAN
100 J/KG) ACROSS PORTIONS OF NORTHERN ILLINOIS THIS AFTERNOON AND
LIFT ASSOCD WITH MCV PUSHING EAST ACROSS THE REGION WILL SUPPORT
ONGOING SHOWERS...BUT EXPECT THUNDER CHANCES TO BE FAIRLY LOW WITH
LIMITED INSTABILITY. ONCE THIS AREA OF PRECIP MOVES EAST...EXPECT A
DRY PERIOD THIS EVENING WITH SUBSIDENCE IN PLACE.
TONIGHT...SURFACE FRONT WILL LIFT NORTH OF THE REGION THIS EVENING
WITH SURFACE TEMPS/DEWPOINTS RISING INTO THE 60S OVERNIGHT. H5
HEIGHT RISES INITIALLY SHOULD INHIBIT ANY DEEP CONVECTION...HOWEVER
A WEAK IMPULSE MOVING EAST ACROSS IOWA WILL MOVE INTO NORTHERN
ILLINOIS AFTER MIDNIGHT TONIGHT AND 50 KT LOW LEVEL JET DEVELOPS OVER
EASTERN KANSAS/NORTHWEST MISSOURI EXTENDING INTO NORTHWESTERN
ILLINOIS. MAX THETA-E CONVERGENCE SETS UP OVER EASTERN IOWA/NORTHERN
ILLINOIS AS MUCAPE RISES TO NEAR 2000 J/KG. BELIEVE THIS WILL BE
BEST FOCUS FOR CONVECTION TONIGHT AND ADJUSTED POPS
ACCORDINGLY...WITH BEST CHANCES //LIKELY POPS// ACROSS
NORTH/NORTHEASTERN PORTIONS OF THE CWA AND TRAILING OFF SOMEWHAT TO
THE SOUTHWEST. AS FAR AS THE SEVERE THREAT TONIGHT...GIVEN THE
UNFAVORABLE DIURNAL TIMING...EXPECT MAINLY ELEVATED ACTIVITY NORTH
OF THE FRONT WITH A MARGINAL SEVERE THREAT GIVEN 30 KT OF DEEP LAYER
SHEAR AND SKINNY CAPE PROFILES.
WEDNESDAY AND WEDNESDAY NIGHT...MURKY SCENARIO PRESENTS ITSELF
WEDNESDAY AND WILL LIKELY HINGE ON COLD POOL/OUTFLOW DEVELOPMENT
FROM TONIGHTS CONVECTION. SYNOPTICALLY...WE SHOULD BE WELL INTO THE
WARM SECTOR WITH SOME GUIDANCE NOW SUGGESTING TEMPERATURES INTO THE
LOW 90S SOUTH OF I-80. WAS MORE CONSERVATIVE THAN THAT...BUT DID
BUMP UP TEMPERATURES SLIGHTLY FROM GOING FORECAST. VERY WEAK LAPSE
RATES BETWEEN 900-700MB AND MODEST INVERSION WILL HELP KEEP THE
ATMOSPHERE WEAKLY CAPPED...BUT STRONG INSTABILITY IS EXPECTED TO
DEVELOP WITH NAM INDICATING MLCAPE VALUES REACHING 3000 J/KG BY
WEDNESDAY AFTERNOON. MODELS DO NOT INDICATE ANY UPPER LEVEL SUPPORT
FOR LARGE SCALE ASCENT THIS FAR SOUTH AND MAIN UNCERTAINTY HINGES ON
OUTFLOW DEVELOPMENT PUSHING EFFECTIVE WARM FRONT FARTHER SOUTH AND
BECOMING FOCUS FOR DEVELOPMENT AS SUGGESTED BY 12Z LSX WRF AS WELL
AS THE 12Z NAM RUNS. MOST OTHER GUIDANCE SEEMS TO FOCUS ON AREAS
FARTHER NORTH. GIVEN HIGH DEGREE OF UNCERTAINTY...OPTED TO LEAVE
POPS AS THEY WERE...WITH LOW CHANCE POPS ACROSS THE NORTH AND SLIGHT
CHANCE ACROSS THE SOUTH. GIVEN THIS...THERE IS CONDITIONAL THREAT
FOR SEVERE WEATHER SHOULD THUNDERSTORMS DEVELOP. MODEST WESTERLIES
ALOFT WILL LEAD TO MARGINAL SHEAR...PARTICULARLY ACROSS NORTHERN
PORTIONS OF THE CWA....ALONG WITH THE STRONG INSTABILITY TO SUPPORT
ORGANIZED SEVERE WEATHER WITH MAIN THREATS BEING LARGE HAIL AND
DAMAGING WINDS. WEDNESDAY NIGHT...LOW LEVEL JET IS FORECAST TO
DEVELOP INTO EASTERN NEBRASKA INTO IOWA WITH MEAN DEEP LAYER FLOW
STEERING ANY RESULTANT DEVELOPMENT TO THE EAST-NORTHEAST.
AGAIN...CHANCES ARE BETTER NORTH OF THE CWA BUT WILL MAINTAIN SOME
LOW CHANCE POPS INTO THE NORTHERN PORTIONS OF ILLINOIS WEDNESDAY
NIGHT. STILL FIRMLY INTO THE WARM SECTOR WEDNESDAY NIGHT...EXPECT
TEMPERATURES TO REMAIN UNSEASONABLY WARM...STAYING PROPPED UP IN THE
MID 60S.
THURSDAY THROUGH FRIDAY...VERY SIMILAR SETUP THURSDAY AS COMPARED TO
WEDNESDAY WITH ONGOING ISSUES WITH BOUNDARY PLACEMENT. BY THURSDAY
NIGHT HOWEVER...FRONT MAKES A PUSH TO THE SOUTH ACROSS THE AREA WITH
BETTER CHANCES OF PRECIP ACROSS ILLINOIS AND INDIANA. GUIDANCE IN
FAIRLY DECENT TIMING FROPA EARLY FRIDAY. AS THE FRONT SWEEPS ACROSS
THE REGION...EXPECT TEMPERATURES TO QUICKLY FALL FRIDAY
EVENING...PARTICULARLY AREAS CLOSER TO THE LAKE.
EXTENDED FORECAST...SATURDAY THROUGH TUESDAY...FRONTAL BOUNDARY IS
EXPECTED TO STALL TO OUR SOUTH THEN LIFT BACK NORTH ON
SATURDAY...LINGERING ACROSS THE REGION THROUGH THE WEEKEND AND
BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. THERE IS
A GREAT DEAL OF UNCERTAINTY REGARDING ANY PRECISE TIMING ON PRECIP
AS WELL AS SPECIFICS ON TEMPERATURES AND WHERE THE BAROCLINIC ZONE
SETS UP. SUNDAY FOR EXAMPLE...MODELS INDICATE A NEAR 20 DEGREE
SPREAD ACROSS THE CWA. GIVEN UNCERTAINTY...DID NOT STRAY FROM
BLENDED MODEL SOLUTION FOR THE EXTENDED PORTION OF THE FORECAST. BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* IFR CIGS THROUGH WEDNESDAY MORNING.
* SHOWERS/THUNDERSTORMS OVERNIGHT INTO WEDNESDAY MORNING.
* GUSTY SOUTHWEST WINDS WEDNESDAY AFTERNOON. CMS
//DISCUSSION...UPDATED 03Z...
SOUTHERN EDGE OF IFR/LOW MVFR CIGS NOW EXTENDS GENERALLY ALONG THE
I-80 CORRIDOR AND IS SLOWLY LIFTING NORTH. IF THIS CURRENT MOTION
CONTINUES...COULD SEE LOW CLOUDS SCATTERING OUT BETWEEN 06Z AND
09Z BUT CONFIDENCE REMAINS RATHER LOW. HINTED AT THE CLEARING
TREND WITH TEMPO GROUPS AT MDW/GYY FOR NOW. EVEN IF CLOUDS DO
SCATTER OUT AND/OR LIFT NORTH...COULD SEE FOG AND ADDITIONAL LOW
CLOUDS REFORM...AS THEY DID AT VYS. SO NO SIGNIFICANT CIG CHANGES
WITH THIS UPDATE. CMS
PREVIOUS 00Z DISCUSSION...
MULTIPLE FORECAST CONCERNS THIS PERIOD WITH OVERALL CONFIDENCE
FAIRLY LOW. AREA OF SHOWERS/RAIN WILL CONTINUE TO PUSH EAST OVER
THE NEXT FEW HOURS. A FEW HEAVIER POCKETS HAVE REDUCE VIS TO 1SM
OR SO BUT THIS HAS BEEN TEMPORARY AS IT SHIFTS EAST...EXPECT
PREVAILING VIS TO REMAIN 2-3SM OR BETTER. IFR CIGS SOUTH OF THE
TERMINALS EARLIER THIS AFTERNOON HAVE BEEN COMPLICATED BY THE
SHOWERS AND RAIN AND THUS HAVE NOT PROGRESSED NORTH. HOWEVER...
CIGS HAVE RECENTLY LOWERED TO IFR AT DPA AND ELSEWHERE AND THAT
TREND WILL LIKELY CONTINUE IN THE NEXT HR OR SO AND TRENDS WILL
NEED TO BE MONITORED FOR UPDATES.
ANOTHER WAVE IS FORECAST TO LIFT ACROSS THE AREA OVERNIGHT INTO
WEDNESDAY MORNING WITH SHOWERS/TS SPREADING/DEVELOPING ACROSS
NORTHERN IL DURING THIS TIME PERIOD...AS A WARM FRONT IS LIFTING
NORTH. WHILE THE EXACT LOCATION...DURATION AND INTENSITY REMAINS
SOMEWHAT UNCERTAIN...OPTED TO INCLUDE PREVAILING SHOWERS DURING
THIS TIME PERIOD...THOUGH THE OVERALL DURATION AT ANY ONE LOCATION
MIGHT ONLY BE A FEW HOURS. THIS ACTIVITY SHOULD BE MOVING EAST OR
NORTHEAST BY MID MORNING WITH THE WARM FRONT NORTH OF THE
TERMINALS. WINDS WILL TURN SOUTHWESTERLY AND BEGIN TO INCREASE BY
LATE MORNING OR EARLY AFTERNOON WITH GUSTS 20-25KTS POSSIBLE. CMS
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* MEDIUM CONFIDENCE REGARDING IFR CIGS THIS EVENING/OVERNIGHT.
* LOW CONFIDENCE REGARDING SHOWERS/TS OVERNIGHT INTO WEDNESDAY
MORNING.
* MEDIUM CONFIDENCE REGARDING WINDS. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY THROUGH MONDAY...GENERALLY PREVAILING VFR BUT WITH
PERIODIC CHANCES FOR SHRA/TSRA THROUGH THE PERIOD. BEST CHANCES
FOR TSRA APPEAR TO BE FRIDAY INTO THE WEEKEND. CMS
&&
.MARINE...
215 PM CDT
SERIES OF LOW PRESSURE SYSTEMS WILL TRACK NORTHEAST FROM THE PLAINS
TOWARD HUDSON BAY OVER THE NEXT SEVERAL DAYS. WEAK WARM FRONT SOUTH
OF THE LAKE TODAY WILL MOVE NORTHWARD ACROSS THE LAKE TONIGHT INTO
WEDNESDAY WITH GENERALLY SOUTHERLY FLOW OVER THE LAKE...MUTED
SOMEWHAT BY THE INCREASINGLY STABLE CONDITIONS AS WARMER/MORE HUMID
AIR MASS SPREADS NORTHWARD OVER THE COLD WATERS. THE HUMID AIR
INTERACTING WITH THE COLDER MARINE LAYER COULD RESULT IN AREAS OF
FOG...POSSIBLY DENSE AS HAS BEEN NOTED ALONG THE SOUTHWESTERN SHORES
OF THE LAKE THIS AFTERNOON. VERY LOW CONFIDENCE IN HOW BIG OF A
PROBLEM FOG WILL BECOME OVER THE OPEN LAKE SO WILL INCLUDE MENTION
OF FOG BUT HOLD OFF ON A MARINE FOG ADVISORY FOR OPEN WATERS. A
COUPLE OF THUNDERSTORM COMPLEXES WILL LIKELY MOVE ACROSS THE LAKE
THE NEXT SEVERAL DAYS RESULTING IN OCCASIONALLY DISTURBED/ALTERED
WIND FIELDS...WITH VARIABLE AND POTENTIALLY MUCH STRONGER WINDS
AROUND THUNDERSTORMS.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WATERS UNTIL 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
936 PM CDT TUE MAY 1 2012
.DISCUSSION...
935 PM CDT
SURFACE QUASI-WARM FRONT WAS ANALYZED ALONG THE SOUTHERN PERIPHERY
OF THE WFO LOT CWA THIS EVENING...HAVING BEEN SUPPRESSED BY
WELL-DEFINED MID-LEVEL VORT AND ASSOCIATED SURFACE WAVE THIS
AFTERNOON. EVENING WATER VAPOR IMAGERY INDICATES THIS MID-LEVEL
CIRCULATION IS NOW OVER INDIANA AND SOUTHERN LOWER MICHIGAN AND
MOVING AWAY FROM THE CWA...WITH THE AREA OF RAIN ASSOCIATED WITH
THIS FEATURE ALSO WEAKENING AND MOVING OUT OF THE AREA AT THIS TIME
WITH ONLY A FEW WEAK RADAR RETURNS LINGERING OVER FAR SOUTHERN LAKE
MICHIGAN AND PARTS OF THE EAST/SOUTHEAST CHICAGO METRO COUNTIES.
HAVE ADJUSTED POPS/WX GRIDS ACCORDINGLY...WITH LITTLE POTENTIAL FOR
ORGANIZED PRECIP ANTICIPATED THROUGH AT LEAST MIDNIGHT IN SUBSIDENT
WAKE OF DEPARTING MID-LEVEL VORT.
THE WARM FRONT IS STILL PROGGED TO LIFT NORTH OVERNIGHT...AND THEN
NORTH OF THE FORECAST AREA WEDNESDAY MORNING. SEVERAL FORECAST
CHALLENGES REMAIN FOR THE OVERNIGHT PERIOD HOWEVER...INCLUDING
STEADY/RISING TEMPERATURES WITH WARM FRONT...DEVELOPMENT OF PATCHY
DENSE FOG...AND THE POTENTIAL FOR RENEWED SHOWER AND THUNDERSTORM
DEVELOPMENT DURING THE LATE NIGHT HOURS.
GOES 11-3.9 MICRON IR IMAGERY INDICATES LOW STRATUS IN EASTERLY
LOW-LEVEL FLOW NORTH OF THE SURFACE WARM FRONT AT 02Z...WITH A FEW
NORTHERN IL LOCATIONS SUCH AS VYS DEVELOPING PATCHY DENSE FOG WHERE
SOME BREAKS HAVE FORMED ALONG THE SOUTHERN EDGE OF THE STRATUS DECK.
FARTHER NORTH...A SLOW LOWERING TREND HAS BEEN NOTED IN VISIBILITY
WITH AREAS OF 1-3SM FOG EXPECTED TO PERSIST DURING THE NIGHT WITH
IMPROVEMENT LIKELY FROM THE SOUTH AS WARM SECTOR SPREADS NORTH.
TEMPERATURES HAVE FALLEN INTO THE LOW/MID 50S ALONG THE LAKE
MICHIGAN SHORE...AND WILL LIKELY DIP TO THE UPPER 50S/AROUND 60
ELSEWHERE NORTH OF THE WARM FRONT AND INTO THE LOWER 60S FARTHER
SOUTH. TEMPERATURES WILL THEN LIKELY BECOME STEADY...AND EVEN RISE
LATE TONIGHT HOWEVER AS THE FRONT LIFTS NORTH.
AS FOR PRECIPITATION TRENDS...EXPECT SEVERAL HOURS OF DRY WEATHER AS
MENTIONED ABOVE. EVENING UPPER AIR ANALYSIS DOES INDICATE A 40 KT
MID-LEVEL SPEED MAX UPSTREAM OVER KANSAS THAT IS PROGGED TO
TRANSLATE NORTHEAST OVERNIGHT ALONG WITH A VERY MOIST WARM SECTOR
AIRMASS WITH H9 DEWPOINTS OF 16C NOTED UPSTREAM. SEVERAL RECENT RUNS
OF THE HRRR HAVE DEPICTED ELEVATED CONVECTION DEVELOPING ACROSS
SOUTHEAST IOWA AND MISSOURI THIS EVENING ALONG THE WARM FRONTAL ZONE
AND SPREADING INTO IL BY MIDNIGHT...AND WHILE DEEP MOIST CONVERGENCE
IS ANALYZED ALONG THE FRONT...SATELLITE AND RADAR TRENDS SUGGEST
THIS APPEARS TO BE OVER-FORECAST. A MORE LIKELY SCENARIO IS FOR MCS
OVER FAR SOUTHWESTERN MINNESOTA AND NORTHWEST IOWA TO PROPAGATE
EAST-SOUTHEAST ALONG THE FRONTAL ZONE AND EVENTUALLY WEAKEN AS IT
MOVES INTO THE FORECAST AREA DURING THE PRE-DAWN HOURS OF EARLY
WEDNESDAY.
RATZER
&&
.PREV DISCUSSION...
304 PM CDT
CONCERNS FOR LATEST FORECAST PACKAGE WILL BE DEALING WITH ONGOING
CONVECTIVE CHANCES THROUGH THE WEEK...AS WELL AS IMPACT ON
TEMPERATURES.
TODAY...WELL DEFINED MCV FROM REMNANT MCC MOVING ACROSS CENTRAL
ILLINOIS WITH LINGERING SHOWERS ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA. THIS AFTERNOON...VERY MODEST MUCAPE (LESS THAN
100 J/KG) ACROSS PORTIONS OF NORTHERN ILLINOIS THIS AFTERNOON AND
LIFT ASSOCD WITH MCV PUSHING EAST ACROSS THE REGION WILL SUPPORT
ONGOING SHOWERS...BUT EXPECT THUNDER CHANCES TO BE FAIRLY LOW WITH
LIMITED INSTABILITY. ONCE THIS AREA OF PRECIP MOVES EAST...EXPECT A
DRY PERIOD THIS EVENING WITH SUBSIDENCE IN PLACE.
TONIGHT...SURFACE FRONT WILL LIFT NORTH OF THE REGION THIS EVENING
WITH SURFACE TEMPS/DEWPOINTS RISING INTO THE 60S OVERNIGHT. H5
HEIGHT RISES INITIALLY SHOULD INHIBIT ANY DEEP CONVECTION...HOWEVER
A WEAK IMPULSE MOVING EAST ACROSS IOWA WILL MOVE INTO NORTHERN
ILLINOIS AFTER MIDNIGHT TONIGHT AND 50 KT LOW LEVEL JET DEVELOPS OVER
EASTERN KANSAS/NORTHWEST MISSOURI EXTENDING INTO NORTHWESTERN
ILLINOIS. MAX THETA-E CONVERGENCE SETS UP OVER EASTERN IOWA/NORTHERN
ILLINOIS AS MUCAPE RISES TO NEAR 2000 J/KG. BELIEVE THIS WILL BE
BEST FOCUS FOR CONVECTION TONIGHT AND ADJUSTED POPS
ACCORDINGLY...WITH BEST CHANCES //LIKELY POPS// ACROSS
NORTH/NORTHEASTERN PORTIONS OF THE CWA AND TRAILING OFF SOMEWHAT TO
THE SOUTHWEST. AS FAR AS THE SEVERE THREAT TONIGHT...GIVEN THE
UNFAVORABLE DIURNAL TIMING...EXPECT MAINLY ELEVATED ACTIVITY NORTH
OF THE FRONT WITH A MARGINAL SEVERE THREAT GIVEN 30 KT OF DEEP LAYER
SHEAR AND SKINNY CAPE PROFILES.
WEDNESDAY AND WEDNESDAY NIGHT...MURKY SCENARIO PRESENTS ITSELF
WEDNESDAY AND WILL LIKELY HINGE ON COLD POOL/OUTFLOW DEVELOPMENT
FROM TONIGHTS CONVECTION. SYNOPTICALLY...WE SHOULD BE WELL INTO THE
WARM SECTOR WITH SOME GUIDANCE NOW SUGGESTING TEMPERATURES INTO THE
LOW 90S SOUTH OF I-80. WAS MORE CONSERVATIVE THAN THAT...BUT DID
BUMP UP TEMPERATURES SLIGHTLY FROM GOING FORECAST. VERY WEAK LAPSE
RATES BETWEEN 900-700MB AND MODEST INVERSION WILL HELP KEEP THE
ATMOSPHERE WEAKLY CAPPED...BUT STRONG INSTABILITY IS EXPECTED TO
DEVELOP WITH NAM INDICATING MLCAPE VALUES REACHING 3000 J/KG BY
WEDNESDAY AFTERNOON. MODELS DO NOT INDICATE ANY UPPER LEVEL SUPPORT
FOR LARGE SCALE ASCENT THIS FAR SOUTH AND MAIN UNCERTAINTY HINGES ON
OUTFLOW DEVELOPMENT PUSHING EFFECTIVE WARM FRONT FARTHER SOUTH AND
BECOMING FOCUS FOR DEVELOPMENT AS SUGGESTED BY 12Z LSX WRF AS WELL
AS THE 12Z NAM RUNS. MOST OTHER GUIDANCE SEEMS TO FOCUS ON AREAS
FARTHER NORTH. GIVEN HIGH DEGREE OF UNCERTAINTY...OPTED TO LEAVE
POPS AS THEY WERE...WITH LOW CHANCE POPS ACROSS THE NORTH AND SLIGHT
CHANCE ACROSS THE SOUTH. GIVEN THIS...THERE IS CONDITIONAL THREAT
FOR SEVERE WEATHER SHOULD THUNDERSTORMS DEVELOP. MODEST WESTERLIES
ALOFT WILL LEAD TO MARGINAL SHEAR...PARTICULARLY ACROSS NORTHERN
PORTIONS OF THE CWA....ALONG WITH THE STRONG INSTABILITY TO SUPPORT
ORGANIZED SEVERE WEATHER WITH MAIN THREATS BEING LARGE HAIL AND
DAMAGING WINDS. WEDNESDAY NIGHT...LOW LEVEL JET IS FORECAST TO
DEVELOP INTO EASTERN NEBRASKA INTO IOWA WITH MEAN DEEP LAYER FLOW
STEERING ANY RESULTANT DEVELOPMENT TO THE EAST-NORTHEAST.
AGAIN...CHANCES ARE BETTER NORTH OF THE CWA BUT WILL MAINTAIN SOME
LOW CHANCE POPS INTO THE NORTHERN PORTIONS OF ILLINOIS WEDNESDAY
NIGHT. STILL FIRMLY INTO THE WARM SECTOR WEDNESDAY NIGHT...EXPECT
TEMPERATURES TO REMAIN UNSEASONABLY WARM...STAYING PROPPED UP IN THE
MID 60S.
THURSDAY THROUGH FRIDAY...VERY SIMILAR SETUP THURSDAY AS COMPARED TO
WEDNESDAY WITH ONGOING ISSUES WITH BOUNDARY PLACEMENT. BY THURSDAY
NIGHT HOWEVER...FRONT MAKES A PUSH TO THE SOUTH ACROSS THE AREA WITH
BETTER CHANCES OF PRECIP ACROSS ILLINOIS AND INDIANA. GUIDANCE IN
FAIRLY DECENT TIMING FROPA EARLY FRIDAY. AS THE FRONT SWEEPS ACROSS
THE REGION...EXPECT TEMPERATURES TO QUICKLY FALL FRIDAY
EVENING...PARTICULARLY AREAS CLOSER TO THE LAKE.
EXTENDED FORECAST...SATURDAY THROUGH TUESDAY...FRONTAL BOUNDARY IS
EXPECTED TO STALL TO OUR SOUTH THEN LIFT BACK NORTH ON
SATURDAY...LINGERING ACROSS THE REGION THROUGH THE WEEKEND AND
BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. THERE IS
A GREAT DEAL OF UNCERTAINTY REGARDING ANY PRECISE TIMING ON PRECIP
AS WELL AS SPECIFICS ON TEMPERATURES AND WHERE THE BAROCLINIC ZONE
SETS UP. SUNDAY FOR EXAMPLE...MODELS INDICATE A NEAR 20 DEGREE
SPREAD ACROSS THE CWA. GIVEN UNCERTAINTY...DID NOT STRAY FROM
BLENDED MODEL SOLUTION FOR THE EXTENDED PORTION OF THE FORECAST. BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* IFR CIGS THROUGH WEDNESDAY MORNING.
* SHOWERS THIS EVENING.
* SHOWERS/THUNDERSTORMS OVERNIGHT INTO WEDNESDAY MORNING.
* GUSTY SOUTHWEST WINDS WEDNESDAY AFTERNOON. CMS
//DISCUSSION...UPDATED 00Z...
MULTIPLE FORECAST CONCERNS THIS PERIOD WITH OVERALL CONFIDENCE
FAIRLY LOW. AREA OF SHOWERS/RAIN WILL CONTINUE TO PUSH EAST OVER
THE NEXT FEW HOURS. A FEW HEAVIER POCKETS HAVE REDUCE VIS TO 1SM
OR SO BUT THIS HAS BEEN TEMPORARY AS IT SHIFTS EAST...EXPECT
PREVAILING VIS TO REMAIN 2-3SM OR BETTER. IFR CIGS SOUTH OF THE
TERMINALS EARLIER THIS AFTERNOON HAVE BEEN COMPLICATED BY THE
SHOWERS AND RAIN AND THUS HAVE NOT PROGRESSED NORTH. HOWEVER...
CIGS HAVE RECENTLY LOWERED TO IFR AT DPA AND ELSEWHERE AND THAT
TREND WILL LIKELY CONTINUE IN THE NEXT HR OR SO AND TRENDS WILL
NEED TO BE MONITORED FOR UPDATES.
ANOTHER WAVE IS FORECAST TO LIFT ACROSS THE AREA OVERNIGHT INTO
WEDNESDAY MORNING WITH SHOWERS/TS SPREADING/DEVELOPING ACROSS
NORTHERN IL DURING THIS TIME PERIOD...AS A WARM FRONT IS LIFTING
NORTH. WHILE THE EXACT LOCATION...DURATION AND INTENSITY REMAINS
SOMEWHAT UNCERTAIN...OPTED TO INCLUDE PREVAILING SHOWERS DURING
THIS TIME PERIOD...THOUGH THE OVERALL DURATION AT ANY ONE LOCATION
MIGHT ONLY BE A FEW HOURS. THIS ACTIVITY SHOULD BE MOVING EAST OR
NORTHEAST BY MID MORNING WITH THE WARM FRONT NORTH OF THE
TERMINALS. WINDS WILL TURN SOUTHWESTERLY AND BEGIN TO INCREASE BY
LATE MORNING OR EARLY AFTERNOON WITH GUSTS 20-25KTS POSSIBLE. CMS
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* MEDIUM CONFIDENCE REGARDING IFR CIGS THIS EVENING/OVERNIGHT.
* MEDIUM CONFIDENCE REGARDING SHOWERS THIS EVENING.
* LOW CONFIDENCE REGARDING SHOWERS/TS OVERNIGHT INTO WEDNESDAY
MORNING.
* MEDIUM CONFIDENCE REGARDING WINDS. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY THROUGH MONDAY...GENERALLY PREVAILING VFR BUT WITH
PERIODIC CHANCES FOR SHRA/TSRA THROUGH THE PERIOD. BEST CHANCES
FOR TSRA APPEAR TO BE FRIDAY INTO THE WEEKEND. CMS
&&
.MARINE...
215 PM CDT
SERIES OF LOW PRESSURE SYSTEMS WILL TRACK NORTHEAST FROM THE PLAINS
TOWARD HUDSON BAY OVER THE NEXT SEVERAL DAYS. WEAK WARM FRONT SOUTH
OF THE LAKE TODAY WILL MOVE NORTHWARD ACROSS THE LAKE TONIGHT INTO
WEDNESDAY WITH GENERALLY SOUTHERLY FLOW OVER THE LAKE...MUTED
SOMEWHAT BY THE INCREASINGLY STABLE CONDITIONS AS WARMER/MORE HUMID
AIR MASS SPREADS NORTHWARD OVER THE COLD WATERS. THE HUMID AIR
INTERACTING WITH THE COLDER MARINE LAYER COULD RESULT IN AREAS OF
FOG...POSSIBLY DENSE AS HAS BEEN NOTED ALONG THE SOUTHWESTERN SHORES
OF THE LAKE THIS AFTERNOON. VERY LOW CONFIDENCE IN HOW BIG OF A
PROBLEM FOG WILL BECOME OVER THE OPEN LAKE SO WILL INCLUDE MENTION
OF FOG BUT HOLD OFF ON A MARINE FOG ADVISORY FOR OPEN WATERS. A
COUPLE OF THUNDERSTORM COMPLEXES WILL LIKELY MOVE ACROSS THE LAKE
THE NEXT SEVERAL DAYS RESULTING IN OCCASIONALLY DISTURBED/ALTERED
WIND FIELDS...WITH VARIABLE AND POTENTIALLY MUCH STRONGER WINDS
AROUND THUNDERSTORMS.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WATERS
UNTIL 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
851 PM CDT TUE MAY 1 2012
.DISCUSSION...
ISSUED 845 PM CDT TUE MAY 1 2012
WARM FRONT HAS LIFTED NORTH OF PIA AND BMI EARLY THIS EVENING AND
EXPECT THE BOUNDARY TO SLOWLY MAKE ITS WAY NORTHWARD OVERNIGHT.
THE STRONG TO SEVERE CONVECTION WHICH DEVELOPED ALONG THE WARM
FRONT LATE THIS AFTERNOON HAS SHIFTED WELL EAST OF THE AREA. MAIN
THREAT FOR ORGANIZED CONVECTION WILL BE ALONG A COLD FRONT TO OUR
NORTHWEST...OVER PARTS OF MINNESOTA INTO NW IOWA. SOME OF THE HI-RES
CONVECTIVE ALLOWING MODELS SUGGEST THE CONVECTION TO OUR WEST MAY
MAKE IT INTO THE WEST AND NORTHWEST PORTION OF THE AREA BY DAWN
WEDNESDAY. HIGHEST CHANCE POPS IN GRIDS THIS EVENING WILL CONTINUE
TO BE ACRS THE NORTH...CLOSER TO THE WARM FRONT...AND THEN OVERNIGHT
OVER THE FAR NORTH AND WEST WITH THE POSSIBILITY OF THE PLAINS
CONVECTION MAKING IT INTO OUR AREA BY DAWN. CURRENT FORECAST HAS
THESE TRENDS WELL HANDLED THIS EVENING...AS A RESULT...NO UPDATE
WILL BE NEEDED.
SMITH
&&
.AVIATION...
ISSUED 645 PM CDT TUE MAY 1 2012
LATEST SURFACE MAP INDICATES WARM FRONT HAS SHIFTED NORTH OF THE
TAF SITES EARLY THIS EVENING. THE SCATTERED STRONG TO SEVERE STORMS
WHICH DEVELOPED ALONG THE BOUNDARY...AFFECTING MAINLY CMI AND DVN...
HAVE SHIFTED OFF TO THE EAST. LOOKS AS IF THE MAIN THREAT FOR
CONVECTION TONIGHT WILL BE ALONG AND NORTH OF THE BOUNDARY WITH FOG
THE MAIN THREAT IN OUR AREA. A SECONDARY THREAT WILL BE WITH LOW
LEVEL WIND SHEAR AFTR 06Z...ESP ACRS THE SPI AND PIA TAF SITES BUT
FOR NOW...WILL NOT INCLUDE IN TAFS AS IT APPEARS BORDERLINE AT THIS
TIME. WILL CONTINUE FROM THE PREVIOUS FCST IN BRINGING VSBYS DOWN
TO MVFR AROUND 09Z. WHAT FOG WE DO SEE SHOULD BURN OFF QUICKLY AS
GUSTY SOUTH WINDS DEVELOP ACRS THE AREA WITH WIND GUSTS EXPECTED
AROUND 25 KTS AT TIMES STARTING AFTR 14Z WED.
SMITH
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT TUE MAY 1 2012
A WET BIAS IS INDICATED IN ALL OF THE DETERMINISTIC MODELS AS A
FRONTAL BOUNDARY LIFTS NORTH AS A WARM FRONT TONIGHT...THEN LINGERS
JUST W-NW OF ILLINOIS FOR MUCH OF THE WEEK BEFORE RETURNING AS A
COLD FRONT LATER IN THE WEEKEND. A WARM AND HUMID AIRMASS WILL
DEVELOP OVER C IL TOMORROW BEHIND THE WARM FRONT. THAT SUMMER-
TIME TYPE OF AIRMASS WILL BE RIPE FOR ANY UPPER SHORTWAVES AND
LINGERING SURFACE BOUNDARIES TO BECOME ACTIVE WITH STORMS WHEN ANY
ELEVATED MIXED LAYERS BECOME UNSTABLE ENOUGH FOR SUSTAINED
UPDRAFTS. THE END RESULT IS AN ABUNDANCE OF PRECIP CHANCES
PEPPERED THROUGHOUT THE NEXT 7 DAYS...BUT CONFIDENCE ON RAIN/STORM
COVERAGE IN GENERAL IS LOW.
SHORT TERM...TONIGHT THROUGH THURSDAY.
THE WARM FRONT IS CURRENTLY EXTENDING FROM LOW PRESSURE NEAR
FULTON COUNTY TO THE SE TOWARD TERRE HAUTE. AN MCV ASSOCIATED WITH
THE SURFACE LOW WILL HELP TRIGGER ADDITIONAL SHOWERS AND A FEW
STORMS ACROSS THE NORTH INTO THE EVENING. ADDITIONAL STORMS WILL
BE POSSIBLE ACROSS THE SOUTH INTO THE EVENING AS THE SOUTHERN
PERIPHERY OF THE MCV REMAINS ACTIVE WHERE SUNSHINE WAS MORE
PLENTIFUL TODAY. WE KEPT SLIGHT CHANCE POPS IN ALL AREAS TONIGHT
TO ACCOUNT FOR VARIOUS CONVECTIVE ELEMENTS THAT MAY FESTER UNDER
THE ADVANCING WARM FRONT IN THE NORTH AND THE POST MCV AIRMASS IN
THE SOUTH.
IN OUR COUNTIES...WEDNESDAY SHOULD BE CAPPED WITH WARM AIR ALOFT
FOR MOST OF THE DAY. OUR NORTHERN COUNTIES ARE IN THE DAY 2
SLIGHT RISK FOR SEVERE STORMS...CLOSER TO THE LINGERING WARM
FRONT. THE HRRR MODEL IS SHOWING AN ADVANCING STORM COMPLEX LATER
TONIGHT ACROSS MN/IA. THAT SYSTEM MAY PUT DOWN AN ADDITIONAL
BOUNDARY FROM THE COLD POOL THAT DRIFTS EAST TOWARD IL WED
MORNING. IT MAY BECOME ACTIVE AS PEAK HEATING CREATES SURFACE
BASED INSTABILITY. EVEN IF MORNING CLOUDS AND FOG LINGER IN THAT
AREA THROUGH THE MORNING...ANY EARLY AFTERNOON CLEARING WILL
ALLOW FOR RAPID DESTABILIZATION OF THE AIRMASS IN FAR NW IL AND
AREAS TO THE W-NW NEAR THE WARM FRONT. IF THE CAP BREAKS TO THE
NW...THE STORMS MAY MAINTAIN SEVERE LEVELS INTO SOME OF OUR
COUNTIES...BUT THE FARTHER E-SE THEY PROGRESS INTO THE CAPPED
AIRMASS...THEY SHOULD LOSE SOME STRENGTH. THEREFORE WE ONLY HAVE
SLIGHT CHANCE POPS IN OUR NORTHERN COUNTIES WED/WED NIGHT.
THURSDAY MAY BE A SIMILAR SCENARIO TO WEDNESDAY...AS THE WARM
FRONT/STATIONARY FRONT REMAINS IN PLACE TO OUR NW. OUR NW COUNTIES
ARE IN THE DAY 3 SLIGHT RISK FOR SEVERE STORMS AGAIN AS A RESULT.
NEAR RECORD HIGHS IN THE MID TO UPPER 80S ARE EXPECTED WED AND
THUR AS DEWPOINTS CLIMB INTO THE MID 60S. IT WILL BE AN
UNCOMFORTABLE AIRMASS AFTER THE RELATIVELY COOLER PORTIONS OF
APRIL.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
STORM CHANCES WILL INCREASE FROM NW TO SE ON THURSDAY NIGHT AS LOW
PRESSURE MOVES FROM THE DAKOTAS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD NW IL. STORM CHANCES WILL CONTINUE FRI AND FRI
NIGHT AS THE FRONT STALLS OUT ACROSS SOUTH CENTRAL IL. SATURDAY
MAY SEE A BREAK IN THE ACTION BUT SLIGHT CHANCES WILL CONTINUE DUE
TO THE PROXIMITY OF THE FRONT AND 500MB SHORTWAVES.
HIGHER CHANCES OF SHOWERS AND STORMS WILL DEVELOP LATER SUNDAY
INTO MONDAY AS THE NEXT LOW PRESSURE CENTER MOVES FROM THE CENTRAL
PLAINS INTO C IL ALONG THE FRONT. A COOLER AIRMASS WILL TRY TO
DROP SOUTH INTO OUR PORTION OF IL ON MONDAY NIGHT AND TUESDAY...AS
HIGH PRESSURE FROM CANADA BUILDS SOUTHWARD. SO WE WENT WITH A
COOLING TREND FOR MON AND TUES...WITH TUES HIGHS REMAINING IN THE
60S.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
646 PM CDT TUE MAY 1 2012
.DISCUSSION...
ISSUED 300 PM CDT TUE MAY 1 2012
A WET BIAS IS INDICATED IN ALL OF THE DETERMINISTIC MODELS AS A
FRONTAL BOUNDARY LIFTS NORTH AS A WARM FRONT TONIGHT...THEN LINGERS
JUST W-NW OF ILLINOIS FOR MUCH OF THE WEEK BEFORE RETURNING AS A
COLD FRONT LATER IN THE WEEKEND. A WARM AND HUMID AIRMASS WILL
DEVELOP OVER C IL TOMORROW BEHIND THE WARM FRONT. THAT SUMMER-
TIME TYPE OF AIRMASS WILL BE RIPE FOR ANY UPPER SHORTWAVES AND
LINGERING SURFACE BOUNDARIES TO BECOME ACTIVE WITH STORMS WHEN ANY
ELEVATED MIXED LAYERS BECOME UNSTABLE ENOUGH FOR SUSTAINED
UPDRAFTS. THE END RESULT IS AN ABUNDANCE OF PRECIP CHANCES
PEPPERED THROUGHOUT THE NEXT 7 DAYS...BUT CONFIDENCE ON RAIN/STORM
COVERAGE IN GENERAL IS LOW.
SHORT TERM...TONIGHT THROUGH THURSDAY.
THE WARM FRONT IS CURRENTLY EXTENDING FROM LOW PRESSURE NEAR
FULTON COUNTY TO THE SE TOWARD TERRE HAUTE. AN MCV ASSOCIATED WITH
THE SURFACE LOW WILL HELP TRIGGER ADDITIONAL SHOWERS AND A FEW
STORMS ACROSS THE NORTH INTO THE EVENING. ADDITIONAL STORMS WILL
BE POSSIBLE ACROSS THE SOUTH INTO THE EVENING AS THE SOUTHERN
PERIPHERY OF THE MCV REMAINS ACTIVE WHERE SUNSHINE WAS MORE
PLENTIFUL TODAY. WE KEPT SLIGHT CHANCE POPS IN ALL AREAS TONIGHT
TO ACCOUNT FOR VARIOUS CONVECTIVE ELEMENTS THAT MAY FESTER UNDER
THE ADVANCING WARM FRONT IN THE NORTH AND THE POST MCV AIRMASS IN
THE SOUTH.
IN OUR COUNTIES...WEDNESDAY SHOULD BE CAPPED WITH WARM AIR ALOFT
FOR MOST OF THE DAY. OUR NORTHERN COUNTIES ARE IN THE DAY 2
SLIGHT RISK FOR SEVERE STORMS...CLOSER TO THE LINGERING WARM
FRONT. THE HRRR MODEL IS SHOWING AN ADVANCING STORM COMPLEX LATER
TONIGHT ACROSS MN/IA. THAT SYSTEM MAY PUT DOWN AN ADDITIONAL
BOUNDARY FROM THE COLD POOL THAT DRIFTS EAST TOWARD IL WED
MORNING. IT MAY BECOME ACTIVE AS PEAK HEATING CREATES SURFACE
BASED INSTABILITY. EVEN IF MORNING CLOUDS AND FOG LINGER IN THAT
AREA THROUGH THE MORNING...ANY EARLY AFTERNOON CLEARING WILL
ALLOW FOR RAPID DESTABILIZATION OF THE AIRMASS IN FAR NW IL AND
AREAS TO THE W-NW NEAR THE WARM FRONT. IF THE CAP BREAKS TO THE
NW...THE STORMS MAY MAINTAIN SEVERE LEVELS INTO SOME OF OUR
COUNTIES...BUT THE FARTHER E-SE THEY PROGRESS INTO THE CAPPED
AIRMASS...THEY SHOULD LOSE SOME STRENGTH. THEREFORE WE ONLY HAVE
SLIGHT CHANCE POPS IN OUR NORTHERN COUNTIES WED/WED NIGHT.
THURSDAY MAY BE A SIMILAR SCENARIO TO WEDNESDAY...AS THE WARM
FRONT/STATIONARY FRONT REMAINS IN PLACE TO OUR NW. OUR NW COUNTIES
ARE IN THE DAY 3 SLIGHT RISK FOR SEVERE STORMS AGAIN AS A RESULT.
NEAR RECORD HIGHS IN THE MID TO UPPER 80S ARE EXPECTED WED AND
THUR AS DEWPOINTS CLIMB INTO THE MID 60S. IT WILL BE AN
UNCOMFORTABLE AIRMASS AFTER THE RELATIVELY COOLER PORTIONS OF
APRIL.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
STORM CHANCES WILL INCREASE FROM NW TO SE ON THURSDAY NIGHT AS LOW
PRESSURE MOVES FROM THE DAKOTAS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD NW IL. STORM CHANCES WILL CONTINUE FRI AND FRI
NIGHT AS THE FRONT STALLS OUT ACROSS SOUTH CENTRAL IL. SATURDAY
MAY SEE A BREAK IN THE ACTION BUT SLIGHT CHANCES WILL CONTINUE DUE
TO THE PROXIMITY OF THE FRONT AND 500MB SHORTWAVES.
HIGHER CHANCES OF SHOWERS AND STORMS WILL DEVELOP LATER SUNDAY
INTO MONDAY AS THE NEXT LOW PRESSURE CENTER MOVES FROM THE CENTRAL
PLAINS INTO C IL ALONG THE FRONT. A COOLER AIRMASS WILL TRY TO
DROP SOUTH INTO OUR PORTION OF IL ON MONDAY NIGHT AND TUESDAY...AS
HIGH PRESSURE FROM CANADA BUILDS SOUTHWARD. SO WE WENT WITH A
COOLING TREND FOR MON AND TUES...WITH TUES HIGHS REMAINING IN THE
60S.
&&
.AVIATION...
ISSUED 645 PM CDT TUE MAY 1 2012
LATEST SURFACE MAP INDICATES WARM FRONT HAS SHIFTED NORTH OF THE
TAF SITES EARLY THIS EVENING. THE SCATTERED STRONG TO SEVERE STORMS
WHICH DEVELOPED ALONG THE BOUNDARY...AFFECTING MAINLY CMI AND DVN...
HAVE SHIFTED OFF TO THE EAST. LOOKS AS IF THE MAIN THREAT FOR
CONVECTION TONIGHT WILL BE ALONG AND NORTH OF THE BOUNDARY WITH FOG
THE MAIN THREAT IN OUR AREA. A SECONDARY THREAT WILL BE WITH LOW
LEVEL WIND SHEAR AFTR 06Z...ESP ACRS THE SPI AND PIA TAF SITES BUT
FOR NOW...WILL NOT INCLUDE IN TAFS AS IT APPEARS BORDERLINE AT THIS
TIME. WILL CONTINUE FROM THE PREVIOUS FCST IN BRINGING VSBYS DOWN
TO MVFR AROUND 09Z. WHAT FOG WE DO SEE SHOULD BURN OFF QUICKLY AS
GUSTY SOUTH WINDS DEVELOP ACRS THE AREA WITH WIND GUSTS EXPECTED
AROUND 25 KTS AT TIMES STARTING AFTR 14Z WED.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTHERN INDIANA
845 PM EDT TUE MAY 1 2012
.UPDATE...
MADE ONLY MINOR TWEAKS TO NEAR TERM GRIDS WRT TEMPS AND POPS.
ADJUSTED TEMPS TO BETTER MATCH RECENT OBS AND TREND THROUGH THE
OVERNIGHT. REDUCED POPS FROM SOUTHWEST TO NORTHEAST AFTER 03Z AS
THE MCV OVER NORTHERN ILLINOIS SHOULD PULL THE WARM FRONT THROUGH
OUR REGION AND USHER DRIER CONDITIONS INTO MUCH OF THE FORECAST
AREA. REDUCED EMPHASIS OF THUNDER IN THE VERY NEAR TERM...BUT KEPT
THUNDER MENTION IN FOR THE OVERNIGHT AS SOME ELEVATED INSTABILITY
AND A STRENGTHENING LLJ COULD SPAWN A FEW THUNDERSTORMS ALONG THE
WARM FRONT THROUGH THE OVERNIGHT HOURS....ESPECIALLY ALONG THE
SOUTHERN TIER OF THE CWA WHERE STRONGEST MUCAPE EXISTS.
&&
.AVIATION...
RECENT RADAR TRENDS INDICATE THAT SHOWER DEVELOPMENT
ALONG THE WARM FRONT IS CONTINUING TO INCREASE IN COVERAGE. EXPECT
THESE SHOWERS TO CONTINUE THROUGH THE FIRST PART OF THE OVERNIGHT
HOURS BEFORE DRIER CONDITIONS PREVAIL LATER. WINDS BEHIND THE WARM
FRONT WILL SHIFT TO THE SOUTHWEST BY THE LATE MORNING HOURS
TOMORROW. AS THE WARM SECTOR ENVELOPS MOST OF NORTHERN
INDIANA...SCATTERED THUNDERSTORMS ARE EXPECTED ON WEDNESDAY
AFTERNOON. THIS STORM DEVELOPMENT IS HIGHLY DEPENDENT ON THE TRACK
OF A MCS WHICH WILL DEVELOP OVER NORTHERN IOWA AND SOUTHERN
MINNESOTA TONIGHT. IF THE PRECIPITATION STAYS NORTH OF OUR AREA
AND ALLOWS SURFACE HEATING AND DESTABILIZATION...STORMS ARE
LIKELY...BUT IF THE PRECIPITATION AND RAIN COOLED AIR MOVES OVER
THE AREA IN THE MORNING AND EARLY AFTERNOON...IT WILL LIKELY
INHIBIT CONVECTIVE CHANCES. A 35 KNOT WESTERLY LOW LEVEL JET WILL
DEVELOP TONIGHT...BUT LOW LEVEL SHEAR NOT STRONG ENOUGH TO WARRANT
A MENTION IN THE TAFS.
&&
.PREV DISCUSSION... /ISSUED 319 PM EDT TUE MAY 1 2012/
SHORT TERM...
MANY ISSUES TO SORT OUT IN THE SHORT TERM. MCV MOVING ACROSS THE
REGION TODAY HAS BEEN HANDLED BEST BY HRRR WITH OTHER HI RES
GUIDANCE IN BALLPARK BUT NOT NEAR AS FAST MOVING THIS WAVE
NORTHEAST. HAVE FOLLOWED HRRR FOR GUIDANCE IN THE SHORT TERM. SHOULD
SEE BULK OF PCPN MOVE EAST BEFORE 00Z WITH LINGERING SHOWERS AND FEW
THUNDERSTORMS FAR EAST AFTER 00Z. MEANWHILE...SOME DEVELOPMENT
POSSIBLE SOUTH OF MCV TRACK IN AREA OF INCREASING INSTABILITY LATE
THIS AFTERNOON WHICH COULD MOVE THROUGH CENTRAL AND NORTHERN AREAS
THIS EVENING. PREVIOUS GRIDS HAD LIKELY POPS ALL NIGHT AND THIS
SEEMS OVERDONE GIVEN FASTER ARRIVAL OF MCV AND INCREASING STABILITY
OVERNIGHT. HAVE ADJUSTED GRIDS FOR HIGHER POPS THIS EVENING BUT KEPT
CHANCE POPS OVERNIGHT WITH BOUNDARY IN THE AREA.
NEXT ISSUE IS WITH DEVELOPMENT OF AN MCS OVERNIGHT TO OUR NW AND
TRACK IT WOULD TAKE TOWARD DAYBREAK. NAM12 BRINGS SOUTHERN FRINGE OF
THIS SYSTEM ACROSS NORTHERN AREAS AROUND 12Z WITH GFS SIMILAR. HI
RES WRF NMM ALSO HINTS AT NORTHERN AREAS BEING BRUSHED BY CONVECTION
EARLY WED MORNING. THIS WARRANTS A SLIGHT NUDGE IN POPS EARLY
WEDNESDAY BUT CONFINED TO MID CHANCE RANGE GIVEN MCS UNCERTAINTY.
NAM AND WRF LAY A BOUNDARY OUT ACROSS CENTRAL CWA WEDNESDAY WHICH
THEN CONVECTS IN THE AFTERNOON WITH GROWING INSTABILITY. THIS
INSTABILITY IS CONTINGENT ON CLOUDS BREAKING UP AND AFTERNOON
HEATING BUT WITH SYNOPTIC WARM FRONT WELL NORTH AND STRONG SOUTHWEST
FLOW ALOFT THIS LOOKS PLAUSIBLE. RESULT WOULD BE TSRA DEVELOPMENT
FARTHER SOUTH IN CENTRAL CWA SO HAVE BROUGHT POPS BACK INTO THIS
AREA FOR THE AFTERNOON HOURS. SEVERE THUNDERSTORMS WOULD BE POSSIBLE
GIVEN MARGINAL BULK SHEAR BUT POTENTIALLY LARGE MUCAPE AND HIGH PWAT
VALUES.
TEMPS WILL BE VERY TRICKY WITH VERY WARM AND HUMID AIRMASS IN PLACE
BUT CONVECTIVE DEBRIS AND PCPN LIMITING FACTORS FOR MAX HEATING. ALL
BLEND USED FOR TEMPERATURES THROUGH THE SHORT TERM PERIOD AS THEY
ARE A NICE COMPROMISE BUT CERTAINLY COULD BE A LITTLE WARMER OR
COOLER DEPENDING ON AMOUNT OF SUN.
LONG TERM...THURSDAY THROUGH MONDAY
PERIOD TO BEGIN WITH SUBTLE HEIGHT RISES ACROSS THE UPPER
MIDWEST/NORTHERN GREAT LAKES AS MORE SIGNIFICANT SHORT WAVE UPPER
TROUGH AXIS TRACKS INTO THE PACIFIC NORTHWEST. THIS WILL RESULT IN
WARM FRONT TO CONTINUE TO SURGE NORTHWARD ACROSS THE GREAT LAKES
REGION ON THURSDAY. GENERALLY CAPPED CONDITIONS ARE ANTICIPATED
ACROSS APPROXIMATELY SOUTHERN TWO THIRDS OF THE FORECAST AREA WITH
MAIN QUESTION ON PRECIP CHANCES ACROSS THE FAR NORTH WHERE CAP WILL
LIKELY BE WEAKER. DIFFICULT AT THIS FORECAST DISTANCE TO LATCH ONTO
STRONGER PERIODS OF MID/UPPER LEVEL FORCING WITH MAIN SHORT WAVE
TRACK REMAINING WITH STRONGER BELT OF WESTERLIES FROM THE NORTHERN
PLAINS INTO THE UPPER GREAT LAKES. SEE NO REASON TO DEVIATE FROM
PREVIOUS FORECAST AT THIS TIME WITH LATE AFTERNOON LOW CHANCE TSRA
POPS ACROSS THE FAR NORTH GIVEN AFOREMENTIONED THERMODYNAMIC
PROFILES.
THE MORE PRONOUNCED PACIFIC WAVE IS THEN EXPECTED TO TRACK ACROSS
SOUTHWEST ONTARIO BY THURSDAY NIGHT INTO FRIDAY EVENTUALLY ALLOWING
COLD FRONT TO SHIFT EASTWARD. STRONGER FRONTAL CONVERGENCE MAY BE
CONFINED TO AREAS FURTHER NORTH ACROSS THE GREAT LAKES IN CLOSER
PROXIMITY TO STRONGER UPPER FORCING. HOWEVER WITH MODERATE
INSTABILITY PRECEDING THE FRONT WILL CONTINUE WITH MID RANGE
CHANCE POPS THURSDAY NIGHT THROUGH FRIDAY ACROSS ENTIRE FORECAST
AREA. SEVERE POTENTIAL STILL UNCLEAR FOR THURSDAY NIGHT/FRIDAY DUE
TO UNCERTAINTIES REGARDING UPSTREAM CONVECTION AND IMPACTS ON
INSTABILITY FOR THE LOCAL AREA ALONG WITH WHAT SHOULD BE MORE
MARGINAL DEEP LAYER SHEAR PROFILES FOR THIS PERIOD. NO SIGNIFICANT
CHANGES MADE TO VERY WARM TEMPERATURES IN ADVANCE OF THE FRONT
THURSDAY AFTERNOON WITH HIGHS IN THE MID TO UPPER 80S.
ON SATURDAY...ELONGATED SFC RIDGE AXIS TO BUILD INTO GREAT LAKES
REGION BEHIND THIS BOUNDARY...WITH SLIGHTLY MORE STABLE CONDITIONS.
PRECIP CHANCES ARE BECOMING MORE MUDDLED WITH BETTER ISENTROPIC
UPGLIDE OVER BOUNDARY POSSIBLY REMAINING JUST WEST OF THE AREA
ACROSS MID MS RVR VALLEY. CANNOT DISCOUNT ISOLD/SCT SHRA/TSRA
HOWEVER DUE TO PERSISTENT ELEVATED INSTABILITY. PERHAPS A SLIGHTLY
BETTER CHANCE FOR LATE SUNDAY/SUNDAY EVENING WHEN MID LEVEL RIDGE
IS EXPECTED TO SHIFT SLIGHTLY EASTWARD ACROSS CENTRAL CONUS IN
RESPONSE TO NEXT EASTERN PACIFIC WAVE MOVING ACROSS THE NORTHERN
ROCKIES. HOWEVER...BY LATE WEEKEND/EARLY NEXT WEEK MODEL
DETERMINISTIC/ENSEMBLE SPREADS BECOME MUCH MORE PRONOUNCED WITH
THIS NEXT PACIFIC WAVE. ALSO SIGNIFICANT VARIABILITY EXISTS WITH
EASTERN CANADIAN TROUGH THAT WILL IMPACT TRACK OF UPSTREAM PACIFIC
SYSTEM. GIVEN THESE UNCERTAINTIES...HAVE LOWERED CR ALLBLEND LOW
POPS TO BELOW MENTIONABLE LEVELS AND WILL KEEP MON/TUE DRY AT THIS
TIME.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...BENTLEY
SHORT TERM...LASHLEY
LONG TERM...MARSILI
AVIATION...BENTLEY
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
814 PM EDT TUE MAY 1 2012
UPDATE...
MADE ONLY MINOR TWEAKS TO NEAR TERM GRIDS WRT TEMPS AND POPS.
ADJUSTED TEMPS TO BETTER MATCH RECENT OBS AND TREND THROUGH THE
OVERNIGHT. REDUCED POPS FROM SOUTHWEST TO NORTHEAST AFTER 03Z AS
THE MCV OVER NORTHERN ILLINOIS SHOULD PULL THE WARM FRONT THROUGH
OUR REGION AND USHER DRIER CONDITIONS INTO MUCH OF THE FORECAST
AREA. REDUCED EMPHASIS OF THUNDER IN THE VERY NEAR TERM...BUT KEPT
THUNDER MENTION IN FOR THE OVERNIGHT AS SOME ELEVATED INSTABILITY
AND A STRENGTHENING LLJ COULD SPAWN A FEW THUNDERSTORMS ALONG THE
WARM FRONT THROUGH THE OVERNIGHT HOURS....ESPECIALLY ALONG THE
SOUTHERN TIER OF THE CWA WHERE STRONGEST MUCAPE EXISTS.
AVIATION...
RECENT RADAR TRENDS INDICATE THAT SHOWER DEVELOPMENT
ALONG THE WARM FRONT IS CONTINUING TO INCREASE IN COVERAGE. EXPECT
THESE SHOWERS TO CONTINUE THROUGH THE FIRST PART OF THE OVERNIGHT
HOURS BEFORE DRIER CONDITIONS PREVAIL LATER. WINDS BEHIND THE WARM
FRONT WILL SHIFT TO THE SOUTHWEST BY THE LATE MORNING HOURS
TOMORROW. AS THE WARM SECTOR ENVELOPS MOST OF NORTHERN
INDIANA...SCATTERED THUNDERSTORMS ARE EXPECTED ON WEDNESDAY
AFTERNOON. THIS STORM DEVELOPMENT IS HIGHLY DEPENDENT ON THE TRACK
OF A MCS WHICH WILL DEVELOP OVER NORTHERN IOWA AND SOUTHERN
MINNESOTA TONIGHT. IF THE PRECIPITATION STAYS NORTH OF OUR AREA
AND ALLOWS SURFACE HEATING AND DESTABILIZATION...STORMS ARE
LIKELY...BUT IF THE PRECIPITATION AND RAIN COOLED AIR MOVES OVER
THE AREA IN THE MORNING AND EARLY AFTERNOON...IT WILL LIKELY
INHIBIT CONVECTIVE CHANCES. A 35 KNOT WESTERLY LOW LEVEL JET WILL
DEVELOP TONIGHT...BUT LOW LEVEL SHEAR NOT STRONG ENOUGH TO WARRANT
A MENTION IN THE TAFS.
.PREV DISCUSSION... /ISSUED 319 PM EDT TUE MAY 1 2012/
SHORT TERM...
MANY ISSUES TO SORT OUT IN THE SHORT TERM. MCV MOVING ACROSS THE
REGION TODAY HAS BEEN HANDLED BEST BY HRRR WITH OTHER HI RES
GUIDANCE IN BALLPARK BUT NOT NEAR AS FAST MOVING THIS WAVE
NORTHEAST. HAVE FOLLOWED HRRR FOR GUIDANCE IN THE SHORT TERM. SHOULD
SEE BULK OF PCPN MOVE EAST BEFORE 00Z WITH LINGERING SHOWERS AND FEW
THUNDERSTORMS FAR EAST AFTER 00Z. MEANWHILE...SOME DEVELOPMENT
POSSIBLE SOUTH OF MCV TRACK IN AREA OF INCREASING INSTABILITY LATE
THIS AFTERNOON WHICH COULD MOVE THROUGH CENTRAL AND NORTHERN AREAS
THIS EVENING. PREVIOUS GRIDS HAD LIKELY POPS ALL NIGHT AND THIS
SEEMS OVERDONE GIVEN FASTER ARRIVAL OF MCV AND INCREASING STABILITY
OVERNIGHT. HAVE ADJUSTED GRIDS FOR HIGHER POPS THIS EVENING BUT KEPT
CHANCE POPS OVERNIGHT WITH BOUNDARY IN THE AREA.
NEXT ISSUE IS WITH DEVELOPMENT OF AN MCS OVERNIGHT TO OUR NW AND
TRACK IT WOULD TAKE TOWARD DAYBREAK. NAM12 BRINGS SOUTHERN FRINGE OF
THIS SYSTEM ACROSS NORTHERN AREAS AROUND 12Z WITH GFS SIMILAR. HI
RES WRF NMM ALSO HINTS AT NORTHERN AREAS BEING BRUSHED BY CONVECTION
EARLY WED MORNING. THIS WARRANTS A SLIGHT NUDGE IN POPS EARLY
WEDNESDAY BUT CONFINED TO MID CHANCE RANGE GIVEN MCS UNCERTAINTY.
NAM AND WRF LAY A BOUNDARY OUT ACROSS CENTRAL CWA WEDNESDAY WHICH
THEN CONVECTS IN THE AFTERNOON WITH GROWING INSTABILITY. THIS
INSTABILITY IS CONTINGENT ON CLOUDS BREAKING UP AND AFTERNOON
HEATING BUT WITH SYNOPTIC WARM FRONT WELL NORTH AND STRONG SOUTHWEST
FLOW ALOFT THIS LOOKS PLAUSIBLE. RESULT WOULD BE TSRA DEVELOPMENT
FARTHER SOUTH IN CENTRAL CWA SO HAVE BROUGHT POPS BACK INTO THIS
AREA FOR THE AFTERNOON HOURS. SEVERE THUNDERSTORMS WOULD BE POSSIBLE
GIVEN MARGINAL BULK SHEAR BUT POTENTIALLY LARGE MUCAPE AND HIGH PWAT
VALUES.
TEMPS WILL BE VERY TRICKY WITH VERY WARM AND HUMID AIRMASS IN PLACE
BUT CONVECTIVE DEBRIS AND PCPN LIMITING FACTORS FOR MAX HEATING. ALL
BLEND USED FOR TEMPERATURES THROUGH THE SHORT TERM PERIOD AS THEY
ARE A NICE COMPROMISE BUT CERTAINLY COULD BE A LITTLE WARMER OR
COOLER DEPENDING ON AMOUNT OF SUN.
LONG TERM...THURSDAY THROUGH MONDAY
PERIOD TO BEGIN WITH SUBTLE HEIGHT RISES ACROSS THE UPPER
MIDWEST/NORTHERN GREAT LAKES AS MORE SIGNIFICANT SHORT WAVE UPPER
TROUGH AXIS TRACKS INTO THE PACIFIC NORTHWEST. THIS WILL RESULT IN
WARM FRONT TO CONTINUE TO SURGE NORTHWARD ACROSS THE GREAT LAKES
REGION ON THURSDAY. GENERALLY CAPPED CONDITIONS ARE ANTICIPATED
ACROSS APPROXIMATELY SOUTHERN TWO THIRDS OF THE FORECAST AREA WITH
MAIN QUESTION ON PRECIP CHANCES ACROSS THE FAR NORTH WHERE CAP WILL
LIKELY BE WEAKER. DIFFICULT AT THIS FORECAST DISTANCE TO LATCH ONTO
STRONGER PERIODS OF MID/UPPER LEVEL FORCING WITH MAIN SHORT WAVE
TRACK REMAINING WITH STRONGER BELT OF WESTERLIES FROM THE NORTHERN
PLAINS INTO THE UPPER GREAT LAKES. SEE NO REASON TO DEVIATE FROM
PREVIOUS FORECAST AT THIS TIME WITH LATE AFTERNOON LOW CHANCE TSRA
POPS ACROSS THE FAR NORTH GIVEN AFOREMENTIONED THERMODYNAMIC
PROFILES.
THE MORE PRONOUNCED PACIFIC WAVE IS THEN EXPECTED TO TRACK ACROSS
SOUTHWEST ONTARIO BY THURSDAY NIGHT INTO FRIDAY EVENTUALLY ALLOWING
COLD FRONT TO SHIFT EASTWARD. STRONGER FRONTAL CONVERGENCE MAY BE
CONFINED TO AREAS FURTHER NORTH ACROSS THE GREAT LAKES IN CLOSER
PROXIMITY TO STRONGER UPPER FORCING. HOWEVER WITH MODERATE
INSTABILITY PRECEDING THE FRONT WILL CONTINUE WITH MID RANGE
CHANCE POPS THURSDAY NIGHT THROUGH FRIDAY ACROSS ENTIRE FORECAST
AREA. SEVERE POTENTIAL STILL UNCLEAR FOR THURSDAY NIGHT/FRIDAY DUE
TO UNCERTAINTIES REGARDING UPSTREAM CONVECTION AND IMPACTS ON
INSTABILITY FOR THE LOCAL AREA ALONG WITH WHAT SHOULD BE MORE
MARGINAL DEEP LAYER SHEAR PROFILES FOR THIS PERIOD. NO SIGNIFICANT
CHANGES MADE TO VERY WARM TEMPERATURES IN ADVANCE OF THE FRONT
THURSDAY AFTERNOON WITH HIGHS IN THE MID TO UPPER 80S.
ON SATURDAY...ELONGATED SFC RIDGE AXIS TO BUILD INTO GREAT LAKES
REGION BEHIND THIS BOUNDARY...WITH SLIGHTLY MORE STABLE CONDITIONS.
PRECIP CHANCES ARE BECOMING MORE MUDDLED WITH BETTER ISENTROPIC
UPGLIDE OVER BOUNDARY POSSIBLY REMAINING JUST WEST OF THE AREA
ACROSS MID MS RVR VALLEY. CANNOT DISCOUNT ISOLD/SCT SHRA/TSRA
HOWEVER DUE TO PERSISTENT ELEVATED INSTABILITY. PERHAPS A SLIGHTLY
BETTER CHANCE FOR LATE SUNDAY/SUNDAY EVENING WHEN MID LEVEL RIDGE
IS EXPECTED TO SHIFT SLIGHTLY EASTWARD ACROSS CENTRAL CONUS IN
RESPONSE TO NEXT EASTERN PACIFIC WAVE MOVING ACROSS THE NORTHERN
ROCKIES. HOWEVER...BY LATE WEEKEND/EARLY NEXT WEEK MODEL
DETERMINISTIC/ENSEMBLE SPREADS BECOME MUCH MORE PRONOUNCED WITH
THIS NEXT PACIFIC WAVE. ALSO SIGNIFICANT VARIABILITY EXISTS WITH
EASTERN CANADIAN TROUGH THAT WILL IMPACT TRACK OF UPSTREAM PACIFIC
SYSTEM. GIVEN THESE UNCERTAINTIES...HAVE LOWERED CR ALLBLEND LOW
POPS TO BELOW MENTIONABLE LEVELS AND WILL KEEP MON/TUE DRY AT THIS
TIME.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
UPDATE...BENTLEY
SHORT TERM...LASHLEY
LONG TERM...MARSILI
AVIATION...BENTLEY
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...UPDATED
NWS PADUCAH KY
633 PM CDT TUE MAY 1 2012
.UPDATE...
ISSUED AT 629 PM CDT TUE MAY 1 2012
UPDATED FOR THE 00Z TAF ISSUANCE.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 215 PM CDT TUE MAY 1 2012
WE APPEAR TO BE SOMEWHAT CAPPED THIS AFTERNOON...SOMETHING THAT
BARELY SHOWED UP IN THE RUC MODEL SOUNDING DATA. THE HRRR MODEL
CONTINUED TO UPDATE WITH BANDS OF PCPN ASSOCIATED WITH THE
WEAKENING VORT MAX ACROSS MAINLY SRN IL/SWRN IND/NRN KY...
APPARENTLY NOT TAKING THIS INTO ACCOUNT. HOWEVER...RADAR AT THIS
TIME SHOWED WIDELY SCATTERED SHOWERS BUBBLING UP ACROSS SWRN IND.
WE HAVE WARNINGS AND WATCHES JUST TO OUR EAST. SO...THESE
POTENTIAL STORMS DESERVE WATCHING AS THE 50+KT MID LEVEL JET
EXITS OUR REGION OVER THE NEXT HOUR OR TWO. SUSTAINED 15 KT WINDS
ARE EXPECTED TO SUBSIDE TO AOB 10 KTS OVERNIGHT.
WED WILL BE ANOTHER BREEZY DAY UNDER SWRLY FLOW ALOFT AND A MOIST
SRLY FETCH...BUT NO SIGNIFICANT PCPN IS EXPECTED WITH ANY SFC
FEATURES WELL OUT OF THE AREA. THU SHOULD BE SIMILIAR...EXCEPT
THAT POSSIBLY SOME GULF MOISTURE MAY GET TAPPED IN THE AFTERNOON
MAINLY NEAR THE AR/TN BORDER FOR A SHOWER OR TSTM. ABOVE NORMAL
TEMPS WILL CONTINUE.
.LONG TERM...(FRIDAY THROUGH TUESDAY)
ISSUED AT 215 PM CDT TUE MAY 1 2012
COMPLICATED SYNOPTIC PATTERN ACROSS THE COUNTRY IS RESULTING A LOW
CONFIDENCE FORECAST THROUGHOUT THE EXTENDED PORTION OF THE FORECAST.
THE PERIOD BEGINS WITH A FAIRLY LOW AMPLITUDE FLOW WITH RIDGING FROM
THE SOUTHERN PLAINS THROUGH MUCH OF THE MISSISSIPPI VALLEY...AND
TROUGHING OVER THE PACIFIC NORTHWEST. MOST RECENT RUNS OF THE
GFS/ECMWF/GEM HAVE TRIED TO DIG A TROUGH INTO THE NORTHEAST OVER THE
WEEKEND...WHICH WOULD DRAG A DECENT SURFACE HIGH SOUTHWARD THROUGH
THE GREAT LAKES AND INTO THE OHIO VALLEY. THIS SURFACE HIGH COULD
POSSIBLY BACK-DOOR OUR REGION...EFFECTIVELY UNDERCUTTING THE UPPER
RIDGE...AND COOLING THINGS DOWN A NOTCH OR TWO. ANOTHER SOLUTION
NOTICED IN THE 00Z ECMWF AND 12Z GFS HAS THE ENERGY FROM THE
NORTHWEST MOVING EAST THROUGH THE TOP OF THE RIDGE...AND EVENTUALLY
BRINGING A COLD FRONT EASTWARD INTO THE REGION OVER THE WEEKEND. IN
EITHER SCENARIO...THE MODELS DIFFER IN TIMING OF POTENTIAL FRONTAL
PASSAGES.
WHAT WE CAN CONFIDENTLY SAY AT THIS POINT IS THAT PRIOR TO ANY
FRONTAL PASSAGE...IT WILL BE HOT...HUMID AND MOST LIKELY DRY. THE
AREA WILL BE ON THE NORTHERN PERIPHERY OF THE RIDGE...SO MCS/S MAY
TRACK EAST AND THEN NORTHEAST AROUND OR POSSIBLY THROUGH A PORTION
OF OUR FORECAST AREA...DEPENDING ON THE ACTUAL STRENGTH OF
THE UPPER HIGH/CAPPING INVERSION. THIS COULD BRING OUTFLOW
BOUNDARIES INTO THE AREA TO MESS UP TEMPERATURES...AND POTENTIALLY
PROVIDE A FOCUS FOR THUNDERSTORM DEVELOPMENT.
IN GENERAL WOULD LIKE TO LEAN TOWARD A DRY AND CONTINUED HOT
FORECAST UNTIL THE MODELS LOCK ONTO A REASONABLE SCENARIO.
HOWEVER...GIVEN ALL THE POTENTIAL FLIES IN THE OINTMENT...WILL
LIKELY KEEP SMALL POPS THROUGOUT THE PERIOD...WITH WARM CONDITIONS
CONTINUING THROUGH THE WEEKEND...FOLLOWED BY A MODEST COOLING TREND
EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 629 PM CDT TUE MAY 1 2012
VFR CIGS/VSBYS SHOULD PREVAIL AT ALL SITES THROUGH THE PERIOD.
SOUTHERLY WINDS WILL CONTINUE OVERNIGHT AOB 10 MPH...THEN PICK
BACK UP AFTER 15Z AT 15-20 MPH WITH GUSTS UP TO 25-30 MPH.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
SHORT TERM...JP
LONG TERM....CW
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...CORRECTED
NWS BALTIMORE MD/WASHINGTON DC
923 PM EDT TUE MAY 1 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN OVER THE MID ATLANTIC REGION
THROUGH WEDNESDAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE
AREA THURSDAY AND FRIDAY. ANOTHER COLD FRONT WILL SAG INTO THE
AREA OF THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
OLD FRONTAL BOUNDARY WAS DRAPED ACROSS THE NORTHERN PORTION OF THE
CWA THIS EVENING...JUST SOUTH OF AND ROUGHLY PARALLELING THE
MASON DIXON LINE. MAIN FOCUS FOR THE OVERNIGHT FORECAST IS THE
EASTWARD PROPAGATION OF MCS ACTIVITY OVER SOUTHERN OHIO...THE
LEADING EDGE MAKING IT INTO WESTERN WEST VIRGINIA AT 01Z. HRRR
SHOWS THIS ACTIVITY MOVING EAST THROUGH THE CWA OVERNIGHT...IN A
WEAKENED STATE BUT ALSO WITH ADDITIONAL SOUTHWARD DEVELOPMENT.
HRRR DID A DECENT JOB WITH LEFTOVER MCS ACTIVITY LAST NIGHT...AND
IS PREFERRED OVERNIGHT. NO SEVERE WEATHER IS EXPECTED ALTHOUGH
THUNDERSTORMS WITH LOCALLY STRONG WINDS CAN/T BE RULED OUT ACROSS
THE EXTREME WESTERN CWA BEFORE ADDITIONAL WEAKENING IS LIKELY TO
OCCUR. HAVE INCREASED/EXPANDED POPS FOR MEASURABLE RAIN
OVERNIGHT...AND ALSO INCLUDED THUNDER AS FAR EAST AS THE WESTERN
DC SUBURBS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
MUCH OF THE MID-ATLC WILL STAY IN THE 60S THRU EARLY WED MRNG. A
LARGER SERIES CONVECTIVE COMPLEXES WILL MOVE EWD OVER THE OHIO VLY
OVERNIGHT AND INTO THE CNTRL APLCNS BY THE PREDAWN HRS WED...BUT
LARGELY DISSIPATE BEFORE MOVING THE PAST THE HIGHER TERRAIN. WITHOUT
A BETTER ORGANIZED LIFTING MECHANISM...ONLY SOME SCATTERED BATCHES
OF LIGHT/MOD RAIN WILL BE PRESENT THROUGH THE LATE MRNG/AFTN HRS. A
WEAK BUT BETTER FOCUS FOR ORGANIZED PRECIP WILL BE AN EMBEDDED UPPER
WAVE MOVING ACROSS THE ERN GREAT LAKES BY LATE TMRW. THIS FEATURE
WILL STRETCH DOWN INTO THE CWA...ALLOWING FOR AT LEAST AN ELONGATED
FOCUS FOR SCATTERED SHOWERS AND A FEW TSTMS DURING THE LATE
AFTN/EVE. ONLY WEAK AND ELEVATED INSTABILITY EXPECTED...BUT ANOTHER
SIMILARLY WARM DAY AND A DAY WITHOUT DRY WLY WINDS - SO IT WILL FEEL
A BIT MORE HUMID.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AS WAS DISCUSSED YDA ALL MDLS ARE SHOWING ARE SHOWING WEAK
TROFFING DOWN THE W CST OF THE COUNTRY W/ A WEAK RDG RESPONDING
OVER THE ERN U.S. TEMPS SHOULD BE WARMING THU AFTN INTO THE M80S E
OF THE HIGHLANDS ACROSS MUCH OF THE CWA. I GAVE CONSIDERATION TO
REMOVING POPS ALTOGETHER THU..GIVEN BLDG RDG AND JET RUNNING FAR
TO THE N. GFS BUFKIT IS SHOWING OVR 1000 J/KG CAPE THU AFTN...BUT
WIND FIELD IS QUITE WEAK...AND BLV W/ THIS WARMING AIR MASS ISOLD
CVNCTN IS PSBL OVR THE MTNS DURG THE AFTN WHICH WOULD DRIFT E.
WARMER NGTS ARE XPCTD BOTH WED AND THU NGTS - A60 MUCH OF THE AREA
WED NGT..LM60S THU NGT. FRI LOOKS TO BE EVEN WARMER...REACHING THE
MU80S.
THE XTND MDLS ARE SOMEWHAT DIVERGENT REGARDING THE WKND/ERLY NEXT WK.
ON SAT GFS SHOWS AN UPR TROF OVR QUEBEC W/ A COLD FNT DROPPING
INTO THE MID ATLC. THE ECM IS SLOWER W/ THE FNT BUT REGARDLESS
THINKING IS FRI SHOULD BE THE PEAK OF THE WARMTH DURG THE XTND PD.
GFS ACTUALLY SHOWING HIGH PRES BLDG IN FM ONTARIO ERLR NEXT WK
WHICH WOULD DROP TEMPS CONSIDERABLY. ECM IS SLOWER W/ THE ARRIVAL
OF THE COOLER AIR BUT FOR NOW THINK ERLY PART OF NEXT WK WL SEE
HIGHS IN THE L70S/LOWS IN THE M50S.
WIDESPREAD SVR WX LOOKS TO REMAIN AT BAY THRU THE XTND PD.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
FRONTAL BOUNDARY WILL REMAIN OVER THE AREA THROUGH WEDNESDAY. WILL
HAVE TO CONTEND WITH SEVERAL DISTURBANCES DURING THIS TIME. FIRST
WILL LIKELY BE A WEAKENING MCS OVERNIGHT. HAVE INCLUDED SHRA WITH
MVFR CONDITIONS FOR A 2-3 HOUR PERIOD AT MOST TAF SITES OVERNIGHT
CLOSE TO HRRR TIMING. HAVE NOT INCLUDED TS/CB YET GIVEN
UNCERTAINTY IN INTENSITY AS MCS MOVES EAST. SHRA/TSRA POSSIBLE
AGAIN WEDNESDAY ESPECIALLY IN THE AFTERNOON.
VFR CONDS XPCTD DURG THE BULK OF THE XTND PD. ISOLD TSTMS ARE
PSBL THU AFTN.
&&
.MARINE...
WITH FRONTAL BOUNDARY BISECTING THE BAY...GRADIENT IS FAIRLY WEAK
AND WINDS GENERALLY 10 KT OR LESS ARE EXPECTED OVERNIGHT. SHOWERS
FROM WEAKENED MCS MAY MOVE THROUGH LATE TONIGHT...WITH SHOWERS AND
THUNDERSTORMS POSSIBLE ON WEDNESDAY.
WINDS BLO SCA LVLS XPCTD THU AND FRI. ISOLD TSTMS PSBL WED EVE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BPP/GMS/ABW
NEAR TERM...BPP
SHORT TERM...GMS
LONG TERM...ABW
AVIATION...BPP/ABW
MARINE...BPP/ABW
AREA FORECAST DISCUSSION
NWS BALTIMORE MD/WASHINGTON DC
921 PM EDT TUE MAY 1 2012
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN OVER THE MID ATLANTIC REGION
THROUGH WEDNESDAY. A RIDGE OF HIGH PRESSURE WILL BUILD OVER THE
AREA THURSDAY AND FRIDAY. ANOTHER COLD FRONT WILL SAG INTO THE
AREA OF THE WEEKEND.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
OLD FRONTAL BOUNDARY WAS DRAPED ACROSS THE NORTHERN PORTION OF THE
CWA THIS EVENING...JUST SOUTH OF AND ROUGHLY PARALLELING THE
MASON DIXON LINE. MAIN FOCUS FOR THE OVERNIGHT FORECAST IS THE
EASTWARD PROPAGATION OF MCS ACTIVITY OVER SOUTHERN OHIO...THE
LEADING EDGE MAKING IT INTO WESTERN WEST VIRGINIA AT 01Z. HRRR
SHOWS THIS ACTIVITY MOVING EAST THROUGH THE CWA OVERNIGHT...IN A
WEAKENED STATE BUT ALSO WITH ADDITIONAL SOUTHWARD DEVELOPMENT.
HRRR DID A DECENT JOB WITH LEFTOVER MCS ACTIVITY LAST NIGHT...AND
IS PREFERRED OVERNIGHT. NO SEVERE WEATHER IS EXPECTED ALTHOUGH
THUNDERSTORMS WITH LOCALLY STRONG WINDS CAN/T BE RULED OUT ACROSS
THE EXTREME WESTERN CWA BEFORE ADDITIONAL WEAKENING IS LIKELY TO
OCCUR. HAVE INCREASED/EXPANDED POPS FOR MEASURABLE RAIN
OVERNIGHT...AND ALSO INCLUDED THUNDER AS FAR EAST AS THE WESTERN
DC SUBURBS.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM WEDNESDAY/...
MUCH OF THE MID-ATLC WILL STAY IN THE 60S THRU EARLY WED MRNG. A
LARGER SERIES CONVECTIVE COMPLEXES WILL MOVE EWD OVER THE OHIO VLY
OVERNIGHT AND INTO THE CNTRL APLCNS BY THE PREDAWN HRS WED...BUT
LARGELY DISSIPATE BEFORE MOVING THE PAST THE HIGHER TERRAIN.
WITHOUT A BETTER ORGANIZED LIFTING MECHANISM...ONLY SOME SCATTERED
BATCHES OF LIGHT/MOD RAIN WILL BE PRESENT THROUGH THE LATE
MRNG/AFTN HRS. A WEAK BUT BETTER FOCUS FOR ORGANIZED PRECIP WILL
BE AN EMBEDDED UPPER WAVE MOVING ACROSS THE ERN GREAT LAKES BY
LATE TMRW. THIS FEATURE WILL STRETCH DOWN INTO THE CWA...ALLOWING
FOR AT LEAST AN ELONGATED FOCUS FOR SCATTERED SHOWERS AND A FEW
TSTMS DURING THE LATE AFTN/EVE. ONLY WEAK AND ELEVATED INSTABILITY
EXPECTED...BUT ANOTHER SIMILARLY WARM DAY AND A DAY WITHOUT DRY
WLY WINDS - SO IT WILL FEEL A BIT MORE HUMID.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AS WAS DISCUSSED YDA ALL MDLS ARE SHOWING ARE SHOWING WEAK
TROFFING DOWN THE W CST OF THE COUNTRY W/ A WEAK RDG RESPONDING
OVER THE ERN U.S. TEMPS SHOULD BE WARMING THU AFTN INTO THE M80S E
OF THE HIGHLANDS ACROSS MUCH OF THE CWA. I GAVE CONSIDERATION TO
REMOVING POPS ALTOGETHER THU..GIVEN BLDG RDG AND JET RUNNING FAR
TO THE N. GFS BUFKIT IS SHOWING OVR 1000 J/KG CAPE THU AFTN...BUT
WIND FIELD IS QUITE WEAK...AND BLV W/ THIS WARMING AIR MASS ISOLD
CVNCTN IS PSBL OVR THE MTNS DURG THE AFTN WHICH WOULD DRIFT E.
WARMER NGTS ARE XPCTD BOTH WED AND THU NGTS - A60 MUCH OF THE AREA
WED NGT..LM60S THU NGT. FRI LOOKS TO BE EVEN WARMER...REACHING THE MU80S.
THE XTND MDLS ARE SOMEWHAT DIVERGENT REGARDING THE WKND/ERLY NEXT WK.
ON SAT GFS SHOWS AN UPR TROF OVR QUEBEC W/ A COLD FNT DROPPING
INTO THE MID ATLC. THE ECM IS SLOWER W/ THE FNT BUT REGARDLESS
THINKING IS FRI SHOULD BE THE PEAK OF THE WARMTH DURG THE XTND PD.
GFS ACTUALLY SHOWING HIGH PRES BLDG IN FM ONTARIO ERLR NEXT WK
WHICH WOULD DROP TEMPS CONSIDERABLY. ECM IS SLOWER W/ THE ARRIVAL
OF THE COOLER AIR BUT FOR NOW THINK ERLY PART OF NEXT WK WL SEE
HIGHS IN THE L70S/LOWS IN THE M50S.
WIDESPREAD SVR WX LOOKS TO REMAIN AT BAY THRU THE XTND PD.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
FRONTAL BOUNDARY WILL REMAIN OVER THE AREA THROUGH WEDNESDAY. WILL
HAVE TO CONTEND WITH SEVERAL DISTURBANCES DURING THIS TIME. FIRST
WILL LIKELY BE A WEAKENING MCS OVERNIGHT. HAVE INCLUDED SHRA WITH
MVFR CONDITIONS FOR A 2-3 HOUR PERIOD AT MOST TAF SITES OVERNIGHT
CLOSE TO HRRR TIMING. HAVE NOT INCLUDED TS/CB YET GIVEN
UNCERTAINTY IN INTENSITY AS MCS MOVES EAST. SHRA/TSRA POSSIBLE
AGAIN WEDNESDAY ESPECIALLY IN THE AFTERNOON.
VFR CONDS XPCTD DURG THE BULK OF THE XTND PD. ISOLD TSTMS ARE
PSBL THU AFTN.
&&
.MARINE...
WITH FRONTAL BOUNDARY BISECTING THE BAY...GRADIENT IS FAIRLY WEAK
AND WINDS GENERALLY 10 KT OR LESS ARE EXPECTED OVERNIGHT. SHOWERS
FROM WEAKENED MCS MAY MOVE THROUGH LATE TONIGHT...WITH SHOWERS AND
THUNDERSTORMS POSSIBLE ON WEDNESDAY.
WINDS BLO SCA LVLS XPCTD THU AND FRI. ISOLD TSTMS PSBL WED EVE.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BPP/GMS/ABW
NEAR TERM...BPP
SHORT TERM...GMS
LONG TERM...ABW
AVIATION...BPP/ABW
MARINE...BPP/ABW
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 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 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
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 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 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 OMAHA/VALLEY NE
634 PM CDT TUE MAY 1 2012
.AVIATION...
00Z TAFS FOR KOMA...KLNK...AND KOFK.
CURRENT LINE OF CONVECTION TRACKING NORTH OF TAF SITES BUT
SOME CHANCE FOR KOFK AND KOMA IN 02Z-06Z TIME FRAME. OTHERWISE
SOME POTENTIAL FOR IFR CIGS DEVELOPING AFTER 09Z AS FRONT STALLS
OVER THE AREA AND WINDS BECOME LIGHT WITH RATHER MOIST LOW LEVELS
INDICATED EAST OF THE BOUNDARY. CONDITIONS IMPROVE TO VFR AFTER
13Z WITH INCREASING SOUTH WINDS BY 19Z.
&&
.PREV DISCUSSION... /ISSUED 341 PM CDT TUE MAY 1 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY
GOING FCST IS IN GOOD SHAPE...ONLY MINOR TWEAKS MADE. MAIN CONCERN
THEN CONTINUES TO BE PINNING DOWN AREAL COVERAGE OF SVR STORM
ACTIVITY THIS EVENING. AS OF NOW IT APPEARS THAT THE UPPER MIDWEST
WILL BE PRIME FOR SVR STORMS IN ASSOCIATED WITH LIFTING WARM FRONT...
WITH ANOTHER AREA OF RISK ASSOCIATED WITH COOL FRONT CURRENTLY
DROPPING THRU THE DAKOTAS. HRRR AND RAP SOLUTIONS HAVE BEEN RATHER
CONSISTENT TODAY SUGGESTING LINE OF CONVECTION MOVING INTO THE NRN
CWA BY EARLY EVENING. ESRH AROUND 360 M2/S2 AND MUCAPES 2000 J/KG OR
SO SHOULD BE ENOUGH TO POP SOME SVR MAINLY OVER NORTHEAST NEB.
AMPLIFYING TROF DIG OVER THE WRN CONUS WILL REPLACE THE NEAR-ZONAL
FLOW WITH LOW AMPLITUDE UPPER RIDGE GRADUALLY BUILDING OVER THE
PLAINS. THIS WILL ACT TO HINDER BNDRY PROGRESSION ANY FARTHER SOUTH
AND KEEP IT INVOF THE CWA. ON WEDNESDAY...MUCAPES INCREASE TO 4500
J/KG BY AFTERNOON BUT DEEP LAYER SHEAR IS MORE FOCUSED NORTH. THUS
NORTHEAST NEB MAY BE UNDER THE GUN AGAIN LATE WEDNESDAY
AFTN/EVENING. THURSDAY THROUGH FRIDAY MODELS PROG SEVERAL IMPULSES
EJECTING OUT OF THE SOUTHWESTERN STATES MAY HELP DESTABILIZE ENOUGH
TO POP OFF ADDITIONAL CONVECTION.
DEE
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
FAIRLY ACTIVE WEATHER PATTERN SHOULD CONTINUE INTO EARLY NEXT WEEK
AS UPPER TROUGH REMAIN TO OUR WEST...EJECTING WAVES OF ENERGY INTO
THE PLAINS.
WARM ADVECTION FRIDAY NIGHT MAY SPARK THUNDERSTORMS OVER THE
NORTHERN CWA...NORTH OF A EAST-WEST WARM FRONT BISECTING OUR AREA.
THOSE SHOULD MOVE ON OFF TO THE NORTHEAST FAIRLY QUICKLY SATURDAY
MORNING...LEAVING OUR CWA IN A VERY UNSTABLE AIRMASS BY SATURDAY
AFTERNOON. CAPPING UNDER WEAK MID LEVEL RIDGE MAY PRECLUDE
DEVELOPMENT MUCH OF THE DAY...MOST LIKELY WAITING FOR LOWERING
HEIGHTS AS RIDGE SLIDES EAST SATURDAY EVENING. THUNDERSTORMS ARE
GOOD BET THEN...ESPECIALLY IN THE NORTH WHERE A COLD FRONT WILL BE
APPROACHING OVERNIGHT.
THAT FRONT WILL DRIFT ACROSS THE AREA SUNDAY...MAINTAINING A FAIRLY
HIGH CHANCE FOR CONTINUING RAIN AND THUNDER. COOLER AIR WILL
FOLLOW...BUT THE CHANCE FOR RAIN OR SHOWERS WILL STILL EXIST AS
MOIST SOUTHWEST FLOW ALOFT RIDES OVER COOL SURFACE LAYER. THIS
PATTERN PERSISTS THROUGH TUESDAY.
TEMPERATURES LOOK WARM SATURDAY WITH SOUTHERLY FLOW AND MORE
HUMIDITY. HAVE HIGHS IN THE 80S THEN. RAIN AND COLD FRONTAL PASSAGE
WILL COOL HIGHS INTO THE 70S SUNDAY...THEN ONLY 60S FOR MONDAY AND
TUESDAY INFLUENCED BY NORTH TO EAST LOW LEVEL WIND COMPONENT.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
FOBERT
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 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 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
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...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 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 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
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 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.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...14
AREA FORECAST DISCUSSION
NWS TULSA OK
329 AM CDT MON APR 30 2012
.DISCUSSION...
A WEAKENING AREA OF SHOWERS AND THUNDERSTORMS IS PROGRESSING
SOUTHEAST ACROSS NORTHEAST OKLAHOMA EARLY THIS MORNING AND LATEST
RUNS OF THE HRRR SUGGEST THAT AT LEAST A BROKEN BAND OF SHOWERS
AND STORMS WILL MAKE IT THROUGH ALL OF EASTERN OKLAHOMA AND
NORTHWEST ARKANSAS THIS MORNING. RESIDUAL OUTFLOW BOUNDARIES AND
THE OLD FRONTAL BOUNDARY NEAR THE KANSAS AND MISSOURI BORDERS MAY
PROVIDE A FOCUS FOR RENEWED DEVELOPMENT LATER THIS AFTERNOON OR
THIS EVENING BUT BY LATER TONIGHT THE GREATEST CONVECTIVE COVERAGE
IS LIKELY TO BE TO OUR NORTH AND NORTHEAST.
WILL CONTINUE LOW POPS INTO TUESDAY BUT AFTER THAT THE CAPPING
INVERSION STRENGTHENS ENOUGH TO PRECLUDE A MENTION OF CONVECTION.
VERY WARM AND HUMID WEATHER WILL THEN PREVAIL THROUGH AT LEAST
NEXT WEEKEND WITH HIGHS APPROACHING 90 AND LOWS NEAR 70 IN MANY
PLACES.
STAYED CLOSE TO THE WARMER NAM MOS TEMPERATURES THE NEXT COUPLE
DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 80 67 85 68 / 70 20 20 10
FSM 82 66 86 67 / 70 20 10 10
MLC 80 68 84 68 / 50 20 10 10
BVO 78 66 85 67 / 60 30 20 10
FYV 77 63 82 64 / 80 30 20 10
BYV 77 63 82 64 / 70 30 20 10
MKO 80 66 84 67 / 70 20 10 10
MIO 78 66 82 67 / 70 40 20 10
F10 80 67 84 68 / 60 20 10 10
HHW 81 66 84 67 / 50 30 10 10
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...14
LONG TERM....05
PLATE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1131 PM EDT TUE MAY 1 2012
.SYNOPSIS...
A WAVY FRONTAL BOUNDARY TO THE SOUTH OF THE STATE WILL LIFT
SLOWLY BACK TO THE NORTH AS A WARM FRONT WEDNESDAY. THE FRONT WILL
BE IN THE VICINITY FOR THE NEXT SEVERAL DAYS...KEEPING UNSETTLED
WEATHER IN THE FORECAST.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
SEVERAL CLUSTERS OF THUNDERSTORMS MOVING THROUGH THE OHIO
VALLEY...WITH THE LEAD/EASTERN-MOST CLUSTER JUST NOW ENTERING FAR
WRN PA. DRIER AIR TO THE NORTH OF I-70 IS KEEPING THE THUNDER TO
THE SOUTH AND LOSS OF HEATING AND MOISTURE FEED FROM THE S/SE IS
WEAKENING THE STORMS INTO MAINLY STRATIFORM RAIN AS IT MOVES TO
THE EAST. HOWEVER...THE 8H LI/S ARE STILL PROGGED TO GO NEGATIVE
OVERNIGHT AND WILL CONTINUE TO MENTION THUNDER OVER THE WEST AND
SOUTH. HOWEVER...THE 00Z NAM FIRST FEW PDS LEAVE ME WITH NO
CONFIDENCE WHATSOEVER IN IT/S SOLUTION. RUC AND HRRR ARE AT LEAST
ON THE RIGHT TRACK WITH PLACEMENT AND SPEED/DIR OF CURRENT
CONVECTION. SPC MESO ANALYSIS PAGE SHOWS THE UNSTABLE AIR AND BEST
MSTR CONVERGENCE TO THE SOUTH OF THE REGION. MUCH MORE STABLE AIR
IN THE NERN SECTIONS OF THE CWA WILL HAVE THE LEAST CHC OF SEEING
ANY SHOWERS AND SHOULD NOT HAVE THUNDER. THICKER MID AND LOW
CLOUDS ARE MOVING IN AND SEASONABLY MILD LATE EVENING TEMPS WILL
KEEP TEMPS FROM FALLING TOO MUCH FURTHER AFTER MIDNIGHT. LITTLE
CHANGE TO POPS/WX/TEMPS...MAINLY JUST MINOR TWEAKS TO TIMING.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
FIRST CONVECTIVE FEATURE /IN THE FORM OF THE WEAKENED AFOREMENTIONED
MCS/ SLIDES EAST OF THE SUSQ VALLEY DURING THE MID TO LATE MORNING
HOURS. THE STALLED OUT SFC-850 MB FRONT JUST TO OUR SOUTH WILL
RETURN TO THE NE WEDNESDAY...HELPING TO BOOST SFC DEWPOINTS AND
CAPES QUICKLY BY THE AFTERNOON.
A SECOND AND RATHER POTENT ROUND OF CONVECTION IS EXPECTED TO FIRE
DURING THE EARLY AFTERNOON ACROSS WESTERN PENN...AND TRACK EAST
ACROSS THE CENTRAL RIDGE AND VALLEY REGION LATER IN THE
AFTERNOON/EARLY EVENING.
SPC PLACED THE WRN HALF OF THE CWA IN A SLIGHT RISK FOR WED...AND
THIS LOOKS REASONABLE BASED ON THE LARGE SCALE FRONTAL BOUNDARY AND
NEAR SFC OUTFLOW BOUNDARIES LINGERING FROM THE MORNING PRECIP.
THIS COULD BE THE FIRST SIGNIFICANT SEVERE WEATHER EVENT OF THE
SEASON HERE IN CENTRAL PENN. NAM 0-3 KM HELICITY IS RATHER
IMPRESSIVE - CLIMBING TO AROUND 200 M2/S2 AT PEAK HEATING ACROSS FAR
WRN PARTS OF THE FCST AREA...WITH 0-1KM EHI ABOUT 1 M2/S2.
HIGH TEMPS WED WILL VARY FROM THE LOWER 70S ACROSS THE SUSQ VALLEY
/WHICH WILL BE MAINLY CLOUDY WITH A LIGHT SERLY WIND AHEAD OF THE
ADVANCING WARM FRONT/...TO THE UPPER 70S TO NEAR 80F IN THE SCENT/SW
LOW LANDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE 12Z MODELS ARE SHOWING MORE CONTINUITY THEN PREVIOUS RUNS..AND
EVEN CONSIDERING THE EC/S 240HR VERSION. THE GFS ENSEMBLES BEGIN
TO DIVERGE AFTER 00Z FRIDAY. THE 12Z OPERATIONAL EC ACTUALLY TRENDS
TOWARDS THE GFS. THE OVERALL TREND MOVES AN UPPER LEVEL RIDGE OVER
CENTRAL CANADA AS MID LEVEL SHORT WAVES PROPAGATE THROUGH THE WORK
WEEK. ML CAPE WILL BE THE HIGHEST ON THURSDAY...HOWEVER THERE
SHOULD BE A DECENT CAP. IF ANY CONVECTION BREAK THIS CAP THERE
WILL BE A CHANCE FOR THUNDERSTORMS THURSDAY AFTERNOON. FRIDAY HAS
LESS CAPE BUT A WEAK...IF ANY AT ALL...CAP. MOISTURE COULD BE AN
ISSUE AS PWATS WILL BE BETTER THURSDAY ALONG WITH THE TIMING OF A
SHORT WAVE. MAX TEMPS HIGHER ON FRIDAY THOUGH GIVEN CURRENT MOISTURE
FIELDS THE FOCUS SHOULD BE ALONG THE PA/NY BORDER. SO
THUNDERSTORMS ARE POSSIBLE THURSDAY AND FRIDAY AFTERNOON AND HAVE
INCREASED POPS ACCORDINGLY.
EXPECT A FRONT TO TRAVERSE THE AREA SATURDAY...THIS EXTENDING
FROM THE LARGE UPPER LEVEL LOW OVER NORTHERN CANADA. THE LONG TERM
WEATHER WILL BE DICTATED BY THE PROGRESSION AND LOCATION OF THIS
LOW...THE BIGGEST QUESTION IN THE LONG TERM PERIOD. THE GFS HAS
BEEN THE MOST CONSISTENT...HOWEVER THE EC IS HISTORICALLY MORE
ACCURATE. KEPT CONTINUITY AND MADE FEW CHANGES TO THE PREVIOUS
FCST...THOUGH ADJUSTED FOR THE TRENDS. EXPECT PRECIPITATION
CHANCES SATURDAY AFTERNOON AND EARLY EVENING...WITH A GENERALLY DRY
SUNDAY. TEMPERATURES WILL BE COOLER SUNDAY INTO EARLY NEXT WEEK.
&&
.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
BEEN SOME FOG AT BFD. ADJUSTED TAFS FOR FOG.
ALSO ADJUSTED TAFS FOR BAND OF SHOWERS AND STORMS TO THE
WEST. HARD TO SEE MUCH GOING ON...EXCEPT AT SPOTS LIKE
JST. PERHAPS A RUMBLE OF THUNDER THERE...BUT THE STORMS
ARE MOVING INTO A MORE STABLE AIRMASS...AND WE ARE WELL
PAST PEAK HEATING.
THE FRONT WILL RETURN AS A WARM FRONT ON WED...AND SHOULD
MOVE NORTH AND EAST OF THE AREA BY AFT...THUS EXPECT VFR
CONDITIONS. DID BACK OFF THE REAL LOW CONDITIONS SOME...AND
BRING IN VFR CONDITIONS A LITTLE SOONER ON WED...BASED ON
NOT SEEING MUCH IN THE WAY OF SHOWERS AND STORMS OVERNIGHT.
OUTLOOK...
THU...AM LOW CLOUDS/FOG POSS...ESP SOUTH AND EAST IN THE MORNING.
SCT PM TSRA IMPACTS POSS...ESP WEST.
FRI...SCT PM TSRA IMPACTS POSS...ESP NORTH.
SAT...SCT PM TSRA IMPACTS POSS.
SUN...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...LAMBERT/STEINBUGL
LONG TERM...CERU/STEINBUGL
AVIATION...LAMBERT/MARTIN
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1017 PM EDT TUE MAY 1 2012
.SYNOPSIS...
A WAVY FRONTAL BOUNDARY TO THE SOUTH OF THE STATE WILL LIFT
SLOWLY BACK TO THE NORTH AS A WARM FRONT WEDNESDAY. THE FRONT WILL
BE IN THE VICINITY FOR THE NEXT SEVERAL DAYS...KEEPING UNSETTLED
WEATHER IN THE FORECAST.
&&
.NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/...
SEVERAL CLUSTERS OF THUNDERSTORMS MOVING THROUGH THE OHIO
VALLEY...WITH THE LEAD/EASTERN-MOST CLUSTER JUST NOW ENTERING FAR
WRN PA. DRIER AIR TO THE NORTH OF I-70 IS KEEPING THE THUNDER TO
THE SOUTH AND LOSS OF HEATING AND MOISTURE FEED FROM THE S/SE IS
WEAKENING THE STORMS INTO MAINLY STRATIFORM RAIN AS IT MOVES TO
THE EAST. HOWEVER...THE 8H LI/S ARE STILL PROGGED TO GO NEGATIVE
OVERNIGHT AND WILL CONTINUE TO MENTION THUNDER OVER THE WEST AND
SOUTH. HOWEVER...THE 00Z NAM FIRST FEW PDS LEAVE ME WITH NO
CONFIDENCE WHATSOEVER IN IT/S SOLUTION. RUC AND HRRR ARE AT LEAST
ON THE RIGHT TRACK WITH PLACEMENT AND SPEED/DIR OF CURRENT
CONVECTION. SPC MESO ANALYSIS PAGE SHOWS THE UNSTABLE AIR AND BEST
MSTR CONVERGENCE TO THE SOUTH OF THE REGION. MUCH MORE STABLE AIR
IN THE NERN SECTIONS OF THE CWA WILL HAVE THE LEAST CHC OF SEEING
ANY SHOWERS AND SHOULD NOT HAVE THUNDER. THICKER MID AND LOW
CLOUDS ARE MOVING IN AND SEASONABLY MILD LATE EVENING TEMPS WILL
KEEP TEMPS FROM FALLING TOO MUCH FURTHER AFTER MIDNIGHT. LITTLE
CHANGE TO POPS/WX/TEMPS...MAINLY JUST MINOR TWEAKS TO TIMING.
&&
.SHORT TERM /7 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
FIRST CONVECTIVE FEATURE /IN THE FORM OF THE WEAKENED AFOREMENTIONED
MCS/ SLIDES EAST OF THE SUSQ VALLEY DURING THE MID TO LATE MORNING
HOURS. THE STALLED OUT SFC-850 MB FRONT JUST TO OUR SOUTH WILL
RETURN TO THE NE WEDNESDAY...HELPING TO BOOST SFC DEWPOINTS AND
CAPES QUICKLY BY THE AFTERNOON.
A SECOND AND RATHER POTENT ROUND OF CONVECTION IS EXPECTED TO FIRE
DURING THE EARLY AFTERNOON ACROSS WESTERN PENN...AND TRACK EAST
ACROSS THE CENTRAL RIDGE AND VALLEY REGION LATER IN THE
AFTERNOON/EARLY EVENING.
SPC PLACED THE WRN HALF OF THE CWA IN A SLIGHT RISK FOR WED...AND
THIS LOOKS REASONABLE BASED ON THE LARGE SCALE FRONTAL BOUNDARY AND
NEAR SFC OUTFLOW BOUNDARIES LINGERING FROM THE MORNING PRECIP.
THIS COULD BE THE FIRST SIGNIFICANT SEVERE WEATHER EVENT OF THE
SEASON HERE IN CENTRAL PENN. NAM 0-3 KM HELICITY IS RATHER
IMPRESSIVE - CLIMBING TO AROUND 200 M2/S2 AT PEAK HEATING ACROSS FAR
WRN PARTS OF THE FCST AREA...WITH 0-1KM EHI ABOUT 1 M2/S2.
HIGH TEMPS WED WILL VARY FROM THE LOWER 70S ACROSS THE SUSQ VALLEY
/WHICH WILL BE MAINLY CLOUDY WITH A LIGHT SERLY WIND AHEAD OF THE
ADVANCING WARM FRONT/...TO THE UPPER 70S TO NEAR 80F IN THE SCENT/SW
LOW LANDS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
THE 12Z MODELS ARE SHOWING MORE CONTINUITY THEN PREVIOUS RUNS..AND
EVEN CONSIDERING THE EC/S 240HR VERSION. THE GFS ENSEMBLES BEGIN
TO DIVERGE AFTER 00Z FRIDAY. THE 12Z OPERATIONAL EC ACTUALLY TRENDS
TOWARDS THE GFS. THE OVERALL TREND MOVES AN UPPER LEVEL RIDGE OVER
CENTRAL CANADA AS MID LEVEL SHORT WAVES PROPAGATE THROUGH THE WORK
WEEK. ML CAPE WILL BE THE HIGHEST ON THURSDAY...HOWEVER THERE
SHOULD BE A DECENT CAP. IF ANY CONVECTION BREAK THIS CAP THERE
WILL BE A CHANCE FOR THUNDERSTORMS THURSDAY AFTERNOON. FRIDAY HAS
LESS CAPE BUT A WEAK...IF ANY AT ALL...CAP. MOISTURE COULD BE AN
ISSUE AS PWATS WILL BE BETTER THURSDAY ALONG WITH THE TIMING OF A
SHORT WAVE. MAX TEMPS HIGHER ON FRIDAY THOUGH GIVEN CURRENT MOISTURE
FIELDS THE FOCUS SHOULD BE ALONG THE PA/NY BORDER. SO
THUNDERSTORMS ARE POSSIBLE THURSDAY AND FRIDAY AFTERNOON AND HAVE
INCREASED POPS ACCORDINGLY.
EXPECT A FRONT TO TRAVERSE THE AREA SATURDAY...THIS EXTENDING
FROM THE LARGE UPPER LEVEL LOW OVER NORTHERN CANADA. THE LONG TERM
WEATHER WILL BE DICTATED BY THE PROGRESSION AND LOCATION OF THIS
LOW...THE BIGGEST QUESTION IN THE LONG TERM PERIOD. THE GFS HAS
BEEN THE MOST CONSISTENT...HOWEVER THE EC IS HISTORICALLY MORE
ACCURATE. KEPT CONTINUITY AND MADE FEW CHANGES TO THE PREVIOUS
FCST...THOUGH ADJUSTED FOR THE TRENDS. EXPECT PRECIPITATION
CHANCES SATURDAY AFTERNOON AND EARLY EVENING...WITH A GENERALLY DRY
SUNDAY. TEMPERATURES WILL BE COOLER SUNDAY INTO EARLY NEXT WEEK.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
A WEAK COLD FRONT DRIFTING JUST TO THE SOUTH OF THE STATE THIS
AFTERNOON WILL RESULT IN VFR CONDITIONS THIS EVENING.
LIGHTER WINDS...HIGH AMOUNTS OF LLVL MOISTURE...AND SEVERAL HOURS OF
CLEARING EARLY TONIGHT WILL HELP TO CREATE DETERIORATING CONDITIONS
LATE TONIGHT IN AREAS OF MVFR TO IFR CONDITIONS...AND 3-5SM VSBYS
IN FOG. ALSO BANDS OF SHOWERS AND THUNDERSTORMS WILL WORK EASTWARD
FROM THE OH VLY. THE STORMS SHOULD WEAKEN SOME...GIVEN LOWER
DEWPOINTS IN PLACE OVER CENTRAL PA...AND LOSS OF HEATING...BUT
A RUMBLE OF THUNDER WILL BE STILL POSSIBLE...ESPECIALLY ACROSS
WESTERN AREAS.
THE FRONT WILL MOVE NORTH AND EAST OF THE AREA BY WED AFT...
THUS EXPECT VFR CONDITIONS.
OUTLOOK...
THU...AM LOW CLOUDS/FOG POSS...ESP SOUTH AND EAST IN THE MORNING.
SCT PM TSRA IMPACTS POSS...ESP WEST.
FRI...SCT PM TSRA IMPACTS POSS...ESP NORTH.
SAT...SCT PM TSRA IMPACTS POSS.
SUN...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LAMBERT/STEINBUGL
NEAR TERM...DANGELO
SHORT TERM...LAMBERT/STEINBUGL
LONG TERM...CERU/STEINBUGL
AVIATION...LAMBERT/MARTIN
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
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 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 CHICAGO/ROMEOVILLE IL
323 AM CDT WED MAY 2 2012
.DISCUSSION...
935 PM CDT
SURFACE QUASI-WARM FRONT WAS ANALYZED ALONG THE SOUTHERN PERIPHERY
OF THE WFO LOT CWA THIS EVENING...HAVING BEEN SUPPRESSED BY
WELL-DEFINED MID-LEVEL VORT AND ASSOCIATED SURFACE WAVE THIS
AFTERNOON. EVENING WATER VAPOR IMAGERY INDICATES THIS MID-LEVEL
CIRCULATION IS NOW OVER INDIANA AND SOUTHERN LOWER MICHIGAN AND
MOVING AWAY FROM THE CWA...WITH THE AREA OF RAIN ASSOCIATED WITH
THIS FEATURE ALSO WEAKENING AND MOVING OUT OF THE AREA AT THIS TIME
WITH ONLY A FEW WEAK RADAR RETURNS LINGERING OVER FAR SOUTHERN LAKE
MICHIGAN AND PARTS OF THE EAST/SOUTHEAST CHICAGO METRO COUNTIES.
HAVE ADJUSTED POPS/WX GRIDS ACCORDINGLY...WITH LITTLE POTENTIAL FOR
ORGANIZED PRECIP ANTICIPATED THROUGH AT LEAST MIDNIGHT IN SUBSIDENT
WAKE OF DEPARTING MID-LEVEL VORT.
THE WARM FRONT IS STILL PROGGED TO LIFT NORTH OVERNIGHT...AND THEN
NORTH OF THE FORECAST AREA WEDNESDAY MORNING. SEVERAL FORECAST
CHALLENGES REMAIN FOR THE OVERNIGHT PERIOD HOWEVER...INCLUDING
STEADY/RISING TEMPERATURES WITH WARM FRONT...DEVELOPMENT OF PATCHY
DENSE FOG...AND THE POTENTIAL FOR RENEWED SHOWER AND THUNDERSTORM
DEVELOPMENT DURING THE LATE NIGHT HOURS.
GOES 11-3.9 MICRON IR IMAGERY INDICATES LOW STRATUS IN EASTERLY
LOW-LEVEL FLOW NORTH OF THE SURFACE WARM FRONT AT 02Z...WITH A FEW
NORTHERN IL LOCATIONS SUCH AS VYS DEVELOPING PATCHY DENSE FOG WHERE
SOME BREAKS HAVE FORMED ALONG THE SOUTHERN EDGE OF THE STRATUS DECK.
FARTHER NORTH...A SLOW LOWERING TREND HAS BEEN NOTED IN VISIBILITY
WITH AREAS OF 1-3SM FOG EXPECTED TO PERSIST DURING THE NIGHT WITH
IMPROVEMENT LIKELY FROM THE SOUTH AS WARM SECTOR SPREADS NORTH.
TEMPERATURES HAVE FALLEN INTO THE LOW/MID 50S ALONG THE LAKE
MICHIGAN SHORE...AND WILL LIKELY DIP TO THE UPPER 50S/AROUND 60
ELSEWHERE NORTH OF THE WARM FRONT AND INTO THE LOWER 60S FARTHER
SOUTH. TEMPERATURES WILL THEN LIKELY BECOME STEADY...AND EVEN RISE
LATE TONIGHT HOWEVER AS THE FRONT LIFTS NORTH.
AS FOR PRECIPITATION TRENDS...EXPECT SEVERAL HOURS OF DRY WEATHER AS
MENTIONED ABOVE. EVENING UPPER AIR ANALYSIS DOES INDICATE A 40 KT
MID-LEVEL SPEED MAX UPSTREAM OVER KANSAS THAT IS PROGGED TO
TRANSLATE NORTHEAST OVERNIGHT ALONG WITH A VERY MOIST WARM SECTOR
AIRMASS WITH H9 DEWPOINTS OF 16C NOTED UPSTREAM. SEVERAL RECENT RUNS
OF THE HRRR HAVE DEPICTED ELEVATED CONVECTION DEVELOPING ACROSS
SOUTHEAST IOWA AND MISSOURI THIS EVENING ALONG THE WARM FRONTAL ZONE
AND SPREADING INTO IL BY MIDNIGHT...AND WHILE DEEP MOIST CONVERGENCE
IS ANALYZED ALONG THE FRONT...SATELLITE AND RADAR TRENDS SUGGEST
THIS APPEARS TO BE OVER-FORECAST. A MORE LIKELY SCENARIO IS FOR MCS
OVER FAR SOUTHWESTERN MINNESOTA AND NORTHWEST IOWA TO PROPAGATE
EAST-SOUTHEAST ALONG THE FRONTAL ZONE AND EVENTUALLY WEAKEN AS IT
MOVES INTO THE FORECAST AREA DURING THE PRE-DAWN HOURS OF EARLY
WEDNESDAY.
RATZER
//PREV DISCUSSION...
304 PM CDT
CONCERNS FOR LATEST FORECAST PACKAGE WILL BE DEALING WITH ONGOING
CONVECTIVE CHANCES THROUGH THE WEEK...AS WELL AS IMPACT ON
TEMPERATURES.
TODAY...WELL DEFINED MCV FROM REMNANT MCC MOVING ACROSS CENTRAL
ILLINOIS WITH LINGERING SHOWERS ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA. THIS AFTERNOON...VERY MODEST MUCAPE (LESS THAN
100 J/KG) ACROSS PORTIONS OF NORTHERN ILLINOIS THIS AFTERNOON AND
LIFT ASSOCD WITH MCV PUSHING EAST ACROSS THE REGION WILL SUPPORT
ONGOING SHOWERS...BUT EXPECT THUNDER CHANCES TO BE FAIRLY LOW WITH
LIMITED INSTABILITY. ONCE THIS AREA OF PRECIP MOVES EAST...EXPECT A
DRY PERIOD THIS EVENING WITH SUBSIDENCE IN PLACE.
TONIGHT...SURFACE FRONT WILL LIFT NORTH OF THE REGION THIS EVENING
WITH SURFACE TEMPS/DEWPOINTS RISING INTO THE 60S OVERNIGHT. H5
HEIGHT RISES INITIALLY SHOULD INHIBIT ANY DEEP CONVECTION...HOWEVER
A WEAK IMPULSE MOVING EAST ACROSS IOWA WILL MOVE INTO NORTHERN
ILLINOIS AFTER MIDNIGHT TONIGHT AND 50 KT LOW LEVEL JET DEVELOPS OVER
EASTERN KANSAS/NORTHWEST MISSOURI EXTENDING INTO NORTHWESTERN
ILLINOIS. MAX THETA-E CONVERGENCE SETS UP OVER EASTERN IOWA/NORTHERN
ILLINOIS AS MUCAPE RISES TO NEAR 2000 J/KG. BELIEVE THIS WILL BE
BEST FOCUS FOR CONVECTION TONIGHT AND ADJUSTED POPS
ACCORDINGLY...WITH BEST CHANCES //LIKELY POPS// ACROSS
NORTH/NORTHEASTERN PORTIONS OF THE CWA AND TRAILING OFF SOMEWHAT TO
THE SOUTHWEST. AS FAR AS THE SEVERE THREAT TONIGHT...GIVEN THE
UNFAVORABLE DIURNAL TIMING...EXPECT MAINLY ELEVATED ACTIVITY NORTH
OF THE FRONT WITH A MARGINAL SEVERE THREAT GIVEN 30 KT OF DEEP LAYER
SHEAR AND SKINNY CAPE PROFILES.
WEDNESDAY AND WEDNESDAY NIGHT...MURKY SCENARIO PRESENTS ITSELF
WEDNESDAY AND WILL LIKELY HINGE ON COLD POOL/OUTFLOW DEVELOPMENT
FROM TONIGHTS CONVECTION. SYNOPTICALLY...WE SHOULD BE WELL INTO THE
WARM SECTOR WITH SOME GUIDANCE NOW SUGGESTING TEMPERATURES INTO THE
LOW 90S SOUTH OF I-80. WAS MORE CONSERVATIVE THAN THAT...BUT DID
BUMP UP TEMPERATURES SLIGHTLY FROM GOING FORECAST. VERY WEAK LAPSE
RATES BETWEEN 900-700MB AND MODEST INVERSION WILL HELP KEEP THE
ATMOSPHERE WEAKLY CAPPED...BUT STRONG INSTABILITY IS EXPECTED TO
DEVELOP WITH NAM INDICATING MLCAPE VALUES REACHING 3000 J/KG BY
WEDNESDAY AFTERNOON. MODELS DO NOT INDICATE ANY UPPER LEVEL SUPPORT
FOR LARGE SCALE ASCENT THIS FAR SOUTH AND MAIN UNCERTAINTY HINGES ON
OUTFLOW DEVELOPMENT PUSHING EFFECTIVE WARM FRONT FARTHER SOUTH AND
BECOMING FOCUS FOR DEVELOPMENT AS SUGGESTED BY 12Z LSX WRF AS WELL
AS THE 12Z NAM RUNS. MOST OTHER GUIDANCE SEEMS TO FOCUS ON AREAS
FARTHER NORTH. GIVEN HIGH DEGREE OF UNCERTAINTY...OPTED TO LEAVE
POPS AS THEY WERE...WITH LOW CHANCE POPS ACROSS THE NORTH AND SLIGHT
CHANCE ACROSS THE SOUTH. GIVEN THIS...THERE IS CONDITIONAL THREAT
FOR SEVERE WEATHER SHOULD THUNDERSTORMS DEVELOP. MODEST WESTERLIES
ALOFT WILL LEAD TO MARGINAL SHEAR...PARTICULARLY ACROSS NORTHERN
PORTIONS OF THE CWA....ALONG WITH THE STRONG INSTABILITY TO SUPPORT
ORGANIZED SEVERE WEATHER WITH MAIN THREATS BEING LARGE HAIL AND
DAMAGING WINDS. WEDNESDAY NIGHT...LOW LEVEL JET IS FORECAST TO
DEVELOP INTO EASTERN NEBRASKA INTO IOWA WITH MEAN DEEP LAYER FLOW
STEERING ANY RESULTANT DEVELOPMENT TO THE EAST-NORTHEAST.
AGAIN...CHANCES ARE BETTER NORTH OF THE CWA BUT WILL MAINTAIN SOME
LOW CHANCE POPS INTO THE NORTHERN PORTIONS OF ILLINOIS WEDNESDAY
NIGHT. STILL FIRMLY INTO THE WARM SECTOR WEDNESDAY NIGHT...EXPECT
TEMPERATURES TO REMAIN UNSEASONABLY WARM...STAYING PROPPED UP IN THE
MID 60S.
THURSDAY THROUGH FRIDAY...VERY SIMILAR SETUP THURSDAY AS COMPARED TO
WEDNESDAY WITH ONGOING ISSUES WITH BOUNDARY PLACEMENT. BY THURSDAY
NIGHT HOWEVER...FRONT MAKES A PUSH TO THE SOUTH ACROSS THE AREA WITH
BETTER CHANCES OF PRECIP ACROSS ILLINOIS AND INDIANA. GUIDANCE IN
FAIRLY DECENT TIMING FROPA EARLY FRIDAY. AS THE FRONT SWEEPS ACROSS
THE REGION...EXPECT TEMPERATURES TO QUICKLY FALL FRIDAY
EVENING...PARTICULARLY AREAS CLOSER TO THE LAKE.
EXTENDED FORECAST...SATURDAY THROUGH TUESDAY...FRONTAL BOUNDARY IS
EXPECTED TO STALL TO OUR SOUTH THEN LIFT BACK NORTH ON
SATURDAY...LINGERING ACROSS THE REGION THROUGH THE WEEKEND AND
BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. THERE IS
A GREAT DEAL OF UNCERTAINTY REGARDING ANY PRECISE TIMING ON PRECIP
AS WELL AS SPECIFICS ON TEMPERATURES AND WHERE THE BAROCLINIC ZONE
SETS UP. SUNDAY FOR EXAMPLE...MODELS INDICATE A NEAR 20 DEGREE
SPREAD ACROSS THE CWA. GIVEN UNCERTAINTY...DID NOT STRAY FROM
BLENDED MODEL SOLUTION FOR THE EXTENDED PORTION OF THE FORECAST. BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PERIODS OF IFR CIGS/VIS THROUGH THE EARLY MORNING HOURS.
* CHANCE FOR SCT SHOWERS/ISOLD THUNDERSTORMS DEVELOPING DURING THE
EARLY MORNING HOURS.
* GUSTY SOUTHWEST WINDS WEDNESDAY AFTERNOON.
KREIN
//DISCUSSION...UPDATED 06Z...
THE VERY SLOPPY WEATHER WILL CONTINUE FOR THE NRN IL/NWRN INDIANA
TERMINALS WITH MULTIPLE CONCERNS. FOR THE NEXT FEW HOURS...THE
FOCUS WILL BE ON CIGS/VIS. THE DENSER LOW STRATUS IS SHOWING SIGNS
OF SCATTERING...BUT AS THIS OCCURS...VISIBILITY SHOULD DROP. IN
GENERAL...LOCATIONS WITH IMPROVING CEILINGS SHOULD SEE VIS DROP TO
IFR/LIFR WHILE LOCATIONS WHERE THE IFR/LIFR CIGS
REMAIN...VISIBILITY SHOULD BE 2-3SM. ANY WAY YOU CUT
IT...CATEGORICALLY...THERE WILL BE WIDESPREAD IFR/LIFR CONDITIONS
ACROSS NRN IL/IN FOR THE NEXT SEVERAL HOURS.
SHRA/TSRA WILL INCREASINGLY BECOME A CONCERN THROUGH THE NIGHT AS
WELL. LATEST RADAR TRENDS SHOW SCT SHRA DEVELOPING NORTH OF THE
WARM FRONT...IN A ZONE OF STRENGTHENING WARM ADVECTION AND
ISENTROPIC LIFT OVER NRN IL. THIS SCT ACTIVITY IS WELL IN ADVANCE
OF THE SOLID LINE OF CONVECTION MOVING EWD THROUGH IOWA AND SRN
MN. WHILE THE TRENDS IN THE SHORT TERM FORECAST MODELS INDICATE
THAT THE SOLID LINE SHOULD BREAK UP AND WEAKEN THROUGH THE
REMAINDER OF THE NIGHT...WITH THE STRONGEST ACTIVE TS REMAINING
NORTH OF THE IL/WI BORDER...NOT REAL CONFIDENT IN THIS IDEA GIVEN
THE LATEST TRENDS OF STRENGTHENING OF THE LINE OVER WRN
IOWA...INVOF A DEVELOPING SFC WAVE. SO...WHILE HAVE MAINTAINED THE
IDEA OF SCT TS IN THE TAFS FOR THE EARLY MORNING HOURS...WILL
MONITOR CLOSELY TO SEE IF THE TS COVERAGE WILL NEED TO BE BOLSTERED.
FOR THE REMAINDER OF THE DAY...WINDS WILL BECOME MORE SWLY AND
THEN GUSTY IN THE AFTERNOON. GIVEN LITTLE CHANGE IN THE LARGE
SCALE FLOW PATTERN ALOFT AND WITH A WARM FRONT LIFTING NWD THROUGH
THE AREA LATER TODAY...THERE WILL BE CONTINUES CHANCES FOR
SHRA/TSRA OVER THE AREA THROUGH THE AFTERNOON AND INTO THE EVENING.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN CATEGORICAL IFR/LIFR CONDITIONS INTO THE EARLY
MORNING HOURS. LOWER CONFIDENCE IN WHETHER THE IFR/LIFR WILL BE
CIGS OR VIS AS THEY WILL BOTH LIKELY BOUNCE AROUND.
* MEDIUM TO HIGH CONFIDENCE CHANCES FOR SCT SHRA/TSRA THROUGH THE
REMAINDER OF THE NIGHT AND INTO TOMORROW MORNING.
. LOW CONFIDENCE IN THE EXACT TIMING/EXTENT/LOCATION OF SHRA/TSRA.
* MEDIUM CONFIDENCE REGARDING WINDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY THROUGH MONDAY...GENERALLY PREVAILING VFR BUT WITH
PERIODIC CHANCES FOR SHRA/TSRA THROUGH THE PERIOD. BEST CHANCES
FOR TSRA APPEAR TO BE FRIDAY INTO THE WEEKEND. CMS
&&
.MARINE...
315 AM CDT
A SERIES OF LOW PRESSURE SYSTEMS WILL TRACK NORTHEAST FROM THE
PLAINS TOWARD HUDSON BAY OVER THE NEXT SEVERAL DAYS. A WEAK WARM
FRONT ACROSS CENTRAL ILLINOIS AND INDIANA WILL MOVE NORTHWARD
ACROSS THE LAKE TODAY...WITH GENERALLY SOUTHERLY FLOW SETTING UP
OVER THE LAKE. AN INCREASINGLY WARMER/MORE HUMID AIR MASS WILL
CONTINUE TO OVERSPREAD THE RELATIVELY COOLER WATERS...ALLOWING
AREAS OF FOG...POSSIBLY DENSE...TO DEVELOP OVER THE LAKE. WHILE
WINDS OVER THE LAKE WILL REMAIN BELOW 25KT FOR THE NEXT SEVERAL
DAYS...OCCASIONAL PERIODS OF THUNDERSTORMS WILL RESULT IN
OCCASIONALLY DISTURBED/ALTERED WIND FIELDS...WITH VARIABLE AND
POTENTIALLY MUCH STRONGER WINDS AROUND THUNDERSTORMS.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WATERS
UNTIL 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
105 AM CDT WED MAY 2 2012
.DISCUSSION...
935 PM CDT
SURFACE QUASI-WARM FRONT WAS ANALYZED ALONG THE SOUTHERN PERIPHERY
OF THE WFO LOT CWA THIS EVENING...HAVING BEEN SUPPRESSED BY
WELL-DEFINED MID-LEVEL VORT AND ASSOCIATED SURFACE WAVE THIS
AFTERNOON. EVENING WATER VAPOR IMAGERY INDICATES THIS MID-LEVEL
CIRCULATION IS NOW OVER INDIANA AND SOUTHERN LOWER MICHIGAN AND
MOVING AWAY FROM THE CWA...WITH THE AREA OF RAIN ASSOCIATED WITH
THIS FEATURE ALSO WEAKENING AND MOVING OUT OF THE AREA AT THIS TIME
WITH ONLY A FEW WEAK RADAR RETURNS LINGERING OVER FAR SOUTHERN LAKE
MICHIGAN AND PARTS OF THE EAST/SOUTHEAST CHICAGO METRO COUNTIES.
HAVE ADJUSTED POPS/WX GRIDS ACCORDINGLY...WITH LITTLE POTENTIAL FOR
ORGANIZED PRECIP ANTICIPATED THROUGH AT LEAST MIDNIGHT IN SUBSIDENT
WAKE OF DEPARTING MID-LEVEL VORT.
THE WARM FRONT IS STILL PROGGED TO LIFT NORTH OVERNIGHT...AND THEN
NORTH OF THE FORECAST AREA WEDNESDAY MORNING. SEVERAL FORECAST
CHALLENGES REMAIN FOR THE OVERNIGHT PERIOD HOWEVER...INCLUDING
STEADY/RISING TEMPERATURES WITH WARM FRONT...DEVELOPMENT OF PATCHY
DENSE FOG...AND THE POTENTIAL FOR RENEWED SHOWER AND THUNDERSTORM
DEVELOPMENT DURING THE LATE NIGHT HOURS.
GOES 11-3.9 MICRON IR IMAGERY INDICATES LOW STRATUS IN EASTERLY
LOW-LEVEL FLOW NORTH OF THE SURFACE WARM FRONT AT 02Z...WITH A FEW
NORTHERN IL LOCATIONS SUCH AS VYS DEVELOPING PATCHY DENSE FOG WHERE
SOME BREAKS HAVE FORMED ALONG THE SOUTHERN EDGE OF THE STRATUS DECK.
FARTHER NORTH...A SLOW LOWERING TREND HAS BEEN NOTED IN VISIBILITY
WITH AREAS OF 1-3SM FOG EXPECTED TO PERSIST DURING THE NIGHT WITH
IMPROVEMENT LIKELY FROM THE SOUTH AS WARM SECTOR SPREADS NORTH.
TEMPERATURES HAVE FALLEN INTO THE LOW/MID 50S ALONG THE LAKE
MICHIGAN SHORE...AND WILL LIKELY DIP TO THE UPPER 50S/AROUND 60
ELSEWHERE NORTH OF THE WARM FRONT AND INTO THE LOWER 60S FARTHER
SOUTH. TEMPERATURES WILL THEN LIKELY BECOME STEADY...AND EVEN RISE
LATE TONIGHT HOWEVER AS THE FRONT LIFTS NORTH.
AS FOR PRECIPITATION TRENDS...EXPECT SEVERAL HOURS OF DRY WEATHER AS
MENTIONED ABOVE. EVENING UPPER AIR ANALYSIS DOES INDICATE A 40 KT
MID-LEVEL SPEED MAX UPSTREAM OVER KANSAS THAT IS PROGGED TO
TRANSLATE NORTHEAST OVERNIGHT ALONG WITH A VERY MOIST WARM SECTOR
AIRMASS WITH H9 DEWPOINTS OF 16C NOTED UPSTREAM. SEVERAL RECENT RUNS
OF THE HRRR HAVE DEPICTED ELEVATED CONVECTION DEVELOPING ACROSS
SOUTHEAST IOWA AND MISSOURI THIS EVENING ALONG THE WARM FRONTAL ZONE
AND SPREADING INTO IL BY MIDNIGHT...AND WHILE DEEP MOIST CONVERGENCE
IS ANALYZED ALONG THE FRONT...SATELLITE AND RADAR TRENDS SUGGEST
THIS APPEARS TO BE OVER-FORECAST. A MORE LIKELY SCENARIO IS FOR MCS
OVER FAR SOUTHWESTERN MINNESOTA AND NORTHWEST IOWA TO PROPAGATE
EAST-SOUTHEAST ALONG THE FRONTAL ZONE AND EVENTUALLY WEAKEN AS IT
MOVES INTO THE FORECAST AREA DURING THE PRE-DAWN HOURS OF EARLY
WEDNESDAY.
RATZER
//PREV DISCUSSION...
304 PM CDT
CONCERNS FOR LATEST FORECAST PACKAGE WILL BE DEALING WITH ONGOING
CONVECTIVE CHANCES THROUGH THE WEEK...AS WELL AS IMPACT ON
TEMPERATURES.
TODAY...WELL DEFINED MCV FROM REMNANT MCC MOVING ACROSS CENTRAL
ILLINOIS WITH LINGERING SHOWERS ACROSS NORTHERN ILLINOIS AND
NORTHWEST INDIANA. THIS AFTERNOON...VERY MODEST MUCAPE (LESS THAN
100 J/KG) ACROSS PORTIONS OF NORTHERN ILLINOIS THIS AFTERNOON AND
LIFT ASSOCD WITH MCV PUSHING EAST ACROSS THE REGION WILL SUPPORT
ONGOING SHOWERS...BUT EXPECT THUNDER CHANCES TO BE FAIRLY LOW WITH
LIMITED INSTABILITY. ONCE THIS AREA OF PRECIP MOVES EAST...EXPECT A
DRY PERIOD THIS EVENING WITH SUBSIDENCE IN PLACE.
TONIGHT...SURFACE FRONT WILL LIFT NORTH OF THE REGION THIS EVENING
WITH SURFACE TEMPS/DEWPOINTS RISING INTO THE 60S OVERNIGHT. H5
HEIGHT RISES INITIALLY SHOULD INHIBIT ANY DEEP CONVECTION...HOWEVER
A WEAK IMPULSE MOVING EAST ACROSS IOWA WILL MOVE INTO NORTHERN
ILLINOIS AFTER MIDNIGHT TONIGHT AND 50 KT LOW LEVEL JET DEVELOPS OVER
EASTERN KANSAS/NORTHWEST MISSOURI EXTENDING INTO NORTHWESTERN
ILLINOIS. MAX THETA-E CONVERGENCE SETS UP OVER EASTERN IOWA/NORTHERN
ILLINOIS AS MUCAPE RISES TO NEAR 2000 J/KG. BELIEVE THIS WILL BE
BEST FOCUS FOR CONVECTION TONIGHT AND ADJUSTED POPS
ACCORDINGLY...WITH BEST CHANCES //LIKELY POPS// ACROSS
NORTH/NORTHEASTERN PORTIONS OF THE CWA AND TRAILING OFF SOMEWHAT TO
THE SOUTHWEST. AS FAR AS THE SEVERE THREAT TONIGHT...GIVEN THE
UNFAVORABLE DIURNAL TIMING...EXPECT MAINLY ELEVATED ACTIVITY NORTH
OF THE FRONT WITH A MARGINAL SEVERE THREAT GIVEN 30 KT OF DEEP LAYER
SHEAR AND SKINNY CAPE PROFILES.
WEDNESDAY AND WEDNESDAY NIGHT...MURKY SCENARIO PRESENTS ITSELF
WEDNESDAY AND WILL LIKELY HINGE ON COLD POOL/OUTFLOW DEVELOPMENT
FROM TONIGHTS CONVECTION. SYNOPTICALLY...WE SHOULD BE WELL INTO THE
WARM SECTOR WITH SOME GUIDANCE NOW SUGGESTING TEMPERATURES INTO THE
LOW 90S SOUTH OF I-80. WAS MORE CONSERVATIVE THAN THAT...BUT DID
BUMP UP TEMPERATURES SLIGHTLY FROM GOING FORECAST. VERY WEAK LAPSE
RATES BETWEEN 900-700MB AND MODEST INVERSION WILL HELP KEEP THE
ATMOSPHERE WEAKLY CAPPED...BUT STRONG INSTABILITY IS EXPECTED TO
DEVELOP WITH NAM INDICATING MLCAPE VALUES REACHING 3000 J/KG BY
WEDNESDAY AFTERNOON. MODELS DO NOT INDICATE ANY UPPER LEVEL SUPPORT
FOR LARGE SCALE ASCENT THIS FAR SOUTH AND MAIN UNCERTAINTY HINGES ON
OUTFLOW DEVELOPMENT PUSHING EFFECTIVE WARM FRONT FARTHER SOUTH AND
BECOMING FOCUS FOR DEVELOPMENT AS SUGGESTED BY 12Z LSX WRF AS WELL
AS THE 12Z NAM RUNS. MOST OTHER GUIDANCE SEEMS TO FOCUS ON AREAS
FARTHER NORTH. GIVEN HIGH DEGREE OF UNCERTAINTY...OPTED TO LEAVE
POPS AS THEY WERE...WITH LOW CHANCE POPS ACROSS THE NORTH AND SLIGHT
CHANCE ACROSS THE SOUTH. GIVEN THIS...THERE IS CONDITIONAL THREAT
FOR SEVERE WEATHER SHOULD THUNDERSTORMS DEVELOP. MODEST WESTERLIES
ALOFT WILL LEAD TO MARGINAL SHEAR...PARTICULARLY ACROSS NORTHERN
PORTIONS OF THE CWA....ALONG WITH THE STRONG INSTABILITY TO SUPPORT
ORGANIZED SEVERE WEATHER WITH MAIN THREATS BEING LARGE HAIL AND
DAMAGING WINDS. WEDNESDAY NIGHT...LOW LEVEL JET IS FORECAST TO
DEVELOP INTO EASTERN NEBRASKA INTO IOWA WITH MEAN DEEP LAYER FLOW
STEERING ANY RESULTANT DEVELOPMENT TO THE EAST-NORTHEAST.
AGAIN...CHANCES ARE BETTER NORTH OF THE CWA BUT WILL MAINTAIN SOME
LOW CHANCE POPS INTO THE NORTHERN PORTIONS OF ILLINOIS WEDNESDAY
NIGHT. STILL FIRMLY INTO THE WARM SECTOR WEDNESDAY NIGHT...EXPECT
TEMPERATURES TO REMAIN UNSEASONABLY WARM...STAYING PROPPED UP IN THE
MID 60S.
THURSDAY THROUGH FRIDAY...VERY SIMILAR SETUP THURSDAY AS COMPARED TO
WEDNESDAY WITH ONGOING ISSUES WITH BOUNDARY PLACEMENT. BY THURSDAY
NIGHT HOWEVER...FRONT MAKES A PUSH TO THE SOUTH ACROSS THE AREA WITH
BETTER CHANCES OF PRECIP ACROSS ILLINOIS AND INDIANA. GUIDANCE IN
FAIRLY DECENT TIMING FROPA EARLY FRIDAY. AS THE FRONT SWEEPS ACROSS
THE REGION...EXPECT TEMPERATURES TO QUICKLY FALL FRIDAY
EVENING...PARTICULARLY AREAS CLOSER TO THE LAKE.
EXTENDED FORECAST...SATURDAY THROUGH TUESDAY...FRONTAL BOUNDARY IS
EXPECTED TO STALL TO OUR SOUTH THEN LIFT BACK NORTH ON
SATURDAY...LINGERING ACROSS THE REGION THROUGH THE WEEKEND AND
BRINGING ADDITIONAL CHANCES FOR SHOWERS AND THUNDERSTORMS. THERE IS
A GREAT DEAL OF UNCERTAINTY REGARDING ANY PRECISE TIMING ON PRECIP
AS WELL AS SPECIFICS ON TEMPERATURES AND WHERE THE BAROCLINIC ZONE
SETS UP. SUNDAY FOR EXAMPLE...MODELS INDICATE A NEAR 20 DEGREE
SPREAD ACROSS THE CWA. GIVEN UNCERTAINTY...DID NOT STRAY FROM
BLENDED MODEL SOLUTION FOR THE EXTENDED PORTION OF THE FORECAST. BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* PERIODS OF IFR CIGS/VIS THROUGH THE EARLY MORNING HOURS.
* CHANCE FOR SCT SHOWERS/ISOLD THUNDERSTORMS DEVELOPING DURING THE
EARLY MORNING HOURS.
* GUSTY SOUTHWEST WINDS WEDNESDAY AFTERNOON.
KREIN
//DISCUSSION...UPDATED 06Z...
THE VERY SLOPPY WEATHER WILL CONTINUE FOR THE NRN IL/NWRN INDIANA
TERMINALS WITH MULTIPLE CONCERNS. FOR THE NEXT FEW HOURS...THE
FOCUS WILL BE ON CIGS/VIS. THE DENSER LOW STRATUS IS SHOWING SIGNS
OF SCATTERING...BUT AS THIS OCCURS...VISIBILITY SHOULD DROP. IN
GENERAL...LOCATIONS WITH IMPROVING CEILINGS SHOULD SEE VIS DROP TO
IFR/LIFR WHILE LOCATIONS WHERE THE IFR/LIFR CIGS
REMAIN...VISIBILITY SHOULD BE 2-3SM. ANY WAY YOU CUT
IT...CATEGORICALLY...THERE WILL BE WIDESPREAD IFR/LIFR CONDITIONS
ACROSS NRN IL/IN FOR THE NEXT SEVERAL HOURS.
SHRA/TSRA WILL INCREASINGLY BECOME A CONCERN THROUGH THE NIGHT AS
WELL. LATEST RADAR TRENDS SHOW SCT SHRA DEVELOPING NORTH OF THE
WARM FRONT...IN A ZONE OF STRENGTHENING WARM ADVECTION AND
ISENTROPIC LIFT OVER NRN IL. THIS SCT ACTIVITY IS WELL IN ADVANCE
OF THE SOLID LINE OF CONVECTION MOVING EWD THROUGH IOWA AND SRN
MN. WHILE THE TRENDS IN THE SHORT TERM FORECAST MODELS INDICATE
THAT THE SOLID LINE SHOULD BREAK UP AND WEAKEN THROUGH THE
REMAINDER OF THE NIGHT...WITH THE STRONGEST ACTIVE TS REMAINING
NORTH OF THE IL/WI BORDER...NOT REAL CONFIDENT IN THIS IDEA GIVEN
THE LATEST TRENDS OF STRENGTHENING OF THE LINE OVER WRN
IOWA...INVOF A DEVELOPING SFC WAVE. SO...WHILE HAVE MAINTAINED THE
IDEA OF SCT TS IN THE TAFS FOR THE EARLY MORNING HOURS...WILL
MONITOR CLOSELY TO SEE IF THE TS COVERAGE WILL NEED TO BE BOLSTERED.
FOR THE REMAINDER OF THE DAY...WINDS WILL BECOME MORE SWLY AND
THEN GUSTY IN THE AFTERNOON. GIVEN LITTLE CHANGE IN THE LARGE
SCALE FLOW PATTERN ALOFT AND WITH A WARM FRONT LIFTING NWD THROUGH
THE AREA LATER TODAY...THERE WILL BE CONTINUES CHANCES FOR
SHRA/TSRA OVER THE AREA THROUGH THE AFTERNOON AND INTO THE EVENING.
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE IN CATEGORICAL IFR/LIFR CONDITIONS INTO THE EARLY
MORNING HOURS. LOWER CONFIDENCE IN WHETHER THE IFR/LIFR WILL BE
CIGS OR VIS AS THEY WILL BOTH LIKELY BOUNCE AROUND.
* MEDIUM TO HIGH CONFIDENCE CHANCES FOR SCT SHRA/TSRA THROUGH THE
REMAINDER OF THE NIGHT AND INTO TOMORROW MORNING.
. LOW CONFIDENCE IN THE EXACT TIMING/EXTENT/LOCATION OF SHRA/TSRA.
* MEDIUM CONFIDENCE REGARDING WINDS.
KREIN
//OUTLOOK FOR ORD/MDW FOR 12Z THURSDAY-12Z TUESDAY...UPDATED 00Z...
* THURSDAY THROUGH MONDAY...GENERALLY PREVAILING VFR BUT WITH
PERIODIC CHANCES FOR SHRA/TSRA THROUGH THE PERIOD. BEST CHANCES
FOR TSRA APPEAR TO BE FRIDAY INTO THE WEEKEND. CMS
&&
.MARINE...
215 PM CDT
SERIES OF LOW PRESSURE SYSTEMS WILL TRACK NORTHEAST FROM THE PLAINS
TOWARD HUDSON BAY OVER THE NEXT SEVERAL DAYS. WEAK WARM FRONT SOUTH
OF THE LAKE TODAY WILL MOVE NORTHWARD ACROSS THE LAKE TONIGHT INTO
WEDNESDAY WITH GENERALLY SOUTHERLY FLOW OVER THE LAKE...MUTED
SOMEWHAT BY THE INCREASINGLY STABLE CONDITIONS AS WARMER/MORE HUMID
AIR MASS SPREADS NORTHWARD OVER THE COLD WATERS. THE HUMID AIR
INTERACTING WITH THE COLDER MARINE LAYER COULD RESULT IN AREAS OF
FOG...POSSIBLY DENSE AS HAS BEEN NOTED ALONG THE SOUTHWESTERN SHORES
OF THE LAKE THIS AFTERNOON. VERY LOW CONFIDENCE IN HOW BIG OF A
PROBLEM FOG WILL BECOME OVER THE OPEN LAKE SO WILL INCLUDE MENTION
OF FOG BUT HOLD OFF ON A MARINE FOG ADVISORY FOR OPEN WATERS. A
COUPLE OF THUNDERSTORM COMPLEXES WILL LIKELY MOVE ACROSS THE LAKE
THE NEXT SEVERAL DAYS RESULTING IN OCCASIONALLY DISTURBED/ALTERED
WIND FIELDS...WITH VARIABLE AND POTENTIALLY MUCH STRONGER WINDS
AROUND THUNDERSTORMS.
IZZI
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...DENSE FOG ADVISORY...NEARSHORE WATERS
UNTIL 10 AM WEDNESDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1133 PM CDT TUE MAY 1 2012
.DISCUSSION...
ISSUED 845 PM CDT TUE MAY 1 2012
WARM FRONT HAS LIFTED NORTH OF PIA AND BMI EARLY THIS EVENING AND
EXPECT THE BOUNDARY TO SLOWLY MAKE ITS WAY NORTHWARD OVERNIGHT.
THE STRONG TO SEVERE CONVECTION WHICH DEVELOPED ALONG THE WARM
FRONT LATE THIS AFTERNOON HAS SHIFTED WELL EAST OF THE AREA. MAIN
THREAT FOR ORGANIZED CONVECTION WILL BE ALONG A COLD FRONT TO OUR
NORTHWEST...OVER PARTS OF MINNESOTA INTO NW IOWA. SOME OF THE HI-RES
CONVECTIVE ALLOWING MODELS SUGGEST THE CONVECTION TO OUR WEST MAY
MAKE IT INTO THE WEST AND NORTHWEST PORTION OF THE AREA BY DAWN
WEDNESDAY. HIGHEST CHANCE POPS IN GRIDS THIS EVENING WILL CONTINUE
TO BE ACRS THE NORTH...CLOSER TO THE WARM FRONT...AND THEN OVERNIGHT
OVER THE FAR NORTH AND WEST WITH THE POSSIBILITY OF THE PLAINS
CONVECTION MAKING IT INTO OUR AREA BY DAWN. CURRENT FORECAST HAS
THESE TRENDS WELL HANDLED THIS EVENING...AS A RESULT...NO UPDATE
WILL BE NEEDED.
&&
.AVIATION...
ISSUED 1125 PM CDT TUE MAY 1 2012
LITTLE CHANGE FROM PREVIOUS DISCUSSION...THE MAIN FORECAST CONCERNS
WILL BE WITH COVERAGE OF FOG OVERNIGHT AND CHANCES FOR CONVECTION
ACRS THE NORTHERN TAF SITES BY MORNING. FRONTAL BOUNDARY HAS EDGED
BACK SOUTH INTO CENTRAL IL BUT SHOULD START TO PUSH BACK NORTH
AFTR 08Z AS THE LOW LEVEL SOUTHERLY FLOW INCREASES AHEAD OF THE
NEXT WEATHER SYSTEM OUT ACRS THE MISSOURI VALLEY THIS EVENING.
WILL CONTINUE WITH MAINLY MVFR VSBYS IN FOG AS THE OVERALL TRENDS
EARLY THIS EVENING HAVE BEEN FOR SOME RATHER VARIABLE VSBYS NORTH
OF THE FRONTAL BOUNDARY. WITH THE FRONT EXPECTED TO PUSH BACK NORTH
LATE TONIGHT...WINDS SHOULD INCREASE ENOUGH TO KEEP THE FOG FROM
BECOMING TOO DENSE/WIDESPREAD. AS FAR AS RAIN CHANCES...THE CONVECTION
OVER NORTHERN IOWA IS TAKING MORE OF A SE TRACK AND THAT TREND SHOULD
CONTINUE...HOWEVER...WE STILL EXPECT A WEAKENING TREND TO OCCUR BEFORE
THE CONVECTION APPROACHES THE MISSISSIPPI RIVER BY MORNING.
SURROUNDING VAD WIND PROFILES CONTINUE TO SHOW WINDS AT THE 1500-2000
FOOT LEVEL WERE INCREASING AND FORECAST MODELS SUGGEST THIS TREND
WILL CONTINUE OVERNIGHT. AS A RESULT...WILL NEED TO INCLUDE LOW LEVEL
WIND SHEAR AFTR 06Z AT PIA AND SPI...AND AFTR 09Z FOR THE REMAINDER
OF THE FORECAST SITES WITH SW WINDS EXPCTD TO REACH 45 KTS AT 2000
FEET. SFC WINDS ARE EXPECTED TO INCREASE WEDNESDAY MORNING WITH
GUSTS UP TO 25 KTS AT TIMES OUT OF THE SOUTH TO SOUTHWEST.
SMITH
&&
.PREV DISCUSSION...
ISSUED 300 PM CDT TUE MAY 1 2012
A WET BIAS IS INDICATED IN ALL OF THE DETERMINISTIC MODELS AS A
FRONTAL BOUNDARY LIFTS NORTH AS A WARM FRONT TONIGHT...THEN LINGERS
JUST W-NW OF ILLINOIS FOR MUCH OF THE WEEK BEFORE RETURNING AS A
COLD FRONT LATER IN THE WEEKEND. A WARM AND HUMID AIRMASS WILL
DEVELOP OVER C IL TOMORROW BEHIND THE WARM FRONT. THAT SUMMER-
TIME TYPE OF AIRMASS WILL BE RIPE FOR ANY UPPER SHORTWAVES AND
LINGERING SURFACE BOUNDARIES TO BECOME ACTIVE WITH STORMS WHEN ANY
ELEVATED MIXED LAYERS BECOME UNSTABLE ENOUGH FOR SUSTAINED
UPDRAFTS. THE END RESULT IS AN ABUNDANCE OF PRECIP CHANCES
PEPPERED THROUGHOUT THE NEXT 7 DAYS...BUT CONFIDENCE ON RAIN/STORM
COVERAGE IN GENERAL IS LOW.
SHORT TERM...TONIGHT THROUGH THURSDAY.
THE WARM FRONT IS CURRENTLY EXTENDING FROM LOW PRESSURE NEAR
FULTON COUNTY TO THE SE TOWARD TERRE HAUTE. AN MCV ASSOCIATED WITH
THE SURFACE LOW WILL HELP TRIGGER ADDITIONAL SHOWERS AND A FEW
STORMS ACROSS THE NORTH INTO THE EVENING. ADDITIONAL STORMS WILL
BE POSSIBLE ACROSS THE SOUTH INTO THE EVENING AS THE SOUTHERN
PERIPHERY OF THE MCV REMAINS ACTIVE WHERE SUNSHINE WAS MORE
PLENTIFUL TODAY. WE KEPT SLIGHT CHANCE POPS IN ALL AREAS TONIGHT
TO ACCOUNT FOR VARIOUS CONVECTIVE ELEMENTS THAT MAY FESTER UNDER
THE ADVANCING WARM FRONT IN THE NORTH AND THE POST MCV AIRMASS IN
THE SOUTH.
IN OUR COUNTIES...WEDNESDAY SHOULD BE CAPPED WITH WARM AIR ALOFT
FOR MOST OF THE DAY. OUR NORTHERN COUNTIES ARE IN THE DAY 2
SLIGHT RISK FOR SEVERE STORMS...CLOSER TO THE LINGERING WARM
FRONT. THE HRRR MODEL IS SHOWING AN ADVANCING STORM COMPLEX LATER
TONIGHT ACROSS MN/IA. THAT SYSTEM MAY PUT DOWN AN ADDITIONAL
BOUNDARY FROM THE COLD POOL THAT DRIFTS EAST TOWARD IL WED
MORNING. IT MAY BECOME ACTIVE AS PEAK HEATING CREATES SURFACE
BASED INSTABILITY. EVEN IF MORNING CLOUDS AND FOG LINGER IN THAT
AREA THROUGH THE MORNING...ANY EARLY AFTERNOON CLEARING WILL
ALLOW FOR RAPID DESTABILIZATION OF THE AIRMASS IN FAR NW IL AND
AREAS TO THE W-NW NEAR THE WARM FRONT. IF THE CAP BREAKS TO THE
NW...THE STORMS MAY MAINTAIN SEVERE LEVELS INTO SOME OF OUR
COUNTIES...BUT THE FARTHER E-SE THEY PROGRESS INTO THE CAPPED
AIRMASS...THEY SHOULD LOSE SOME STRENGTH. THEREFORE WE ONLY HAVE
SLIGHT CHANCE POPS IN OUR NORTHERN COUNTIES WED/WED NIGHT.
THURSDAY MAY BE A SIMILAR SCENARIO TO WEDNESDAY...AS THE WARM
FRONT/STATIONARY FRONT REMAINS IN PLACE TO OUR NW. OUR NW COUNTIES
ARE IN THE DAY 3 SLIGHT RISK FOR SEVERE STORMS AGAIN AS A RESULT.
NEAR RECORD HIGHS IN THE MID TO UPPER 80S ARE EXPECTED WED AND
THUR AS DEWPOINTS CLIMB INTO THE MID 60S. IT WILL BE AN
UNCOMFORTABLE AIRMASS AFTER THE RELATIVELY COOLER PORTIONS OF
APRIL.
LONG TERM...THURSDAY NIGHT THROUGH TUESDAY.
STORM CHANCES WILL INCREASE FROM NW TO SE ON THURSDAY NIGHT AS LOW
PRESSURE MOVES FROM THE DAKOTAS INTO THE GREAT LAKES...DRAGGING A
COLD FRONT TOWARD NW IL. STORM CHANCES WILL CONTINUE FRI AND FRI
NIGHT AS THE FRONT STALLS OUT ACROSS SOUTH CENTRAL IL. SATURDAY
MAY SEE A BREAK IN THE ACTION BUT SLIGHT CHANCES WILL CONTINUE DUE
TO THE PROXIMITY OF THE FRONT AND 500MB SHORTWAVES.
HIGHER CHANCES OF SHOWERS AND STORMS WILL DEVELOP LATER SUNDAY
INTO MONDAY AS THE NEXT LOW PRESSURE CENTER MOVES FROM THE CENTRAL
PLAINS INTO C IL ALONG THE FRONT. A COOLER AIRMASS WILL TRY TO
DROP SOUTH INTO OUR PORTION OF IL ON MONDAY NIGHT AND TUESDAY...AS
HIGH PRESSURE FROM CANADA BUILDS SOUTHWARD. SO WE WENT WITH A
COOLING TREND FOR MON AND TUES...WITH TUES HIGHS REMAINING IN THE
60S.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 9 AM CDT WEDNESDAY FOR ILZ051.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
134 AM EDT WED MAY 2 2012
.AVIATION.../06Z TAFS/
AREA OF SHRA/TS IN COMMA HEAD OF MCV HAD MOVED EAST OF NRN INDIANA
EARLY THIS MORNING. WAVY SFC WARM FRONT REMAINS SOUTH OF THE AREA
ACROSS CENTRAL IL/IN. THIS FRONT IS EXPECTED TO LIFT SLOWLY NORTH
OVERNIGHT AND THEN PRBLY INCREASE IN SPEED AS STRONGER S-SW WINDS
ALOFT MIX DOWN TO THE SURFACE DURING THE DAY. SOME STRATUS AND FOG
WITH OCNL IFR CONDITIONS EXPECTED AT THE TERMINALS THROUGH THE EARLY
MORNING HOURS. CONDITIONS SHOULD IMPROVE TO VFR BY LATE MORNING.
POTENTIAL FOR MORE TSTMS AT THE TERMINALS OVERNIGHT IS LOW... BUT
NOT ZERO AS LOW LEVEL WAA/ISENT LIFT CONTS ACROSS THE AREA. LEFT
VCTS/CB IN FCST FOR LATE AFTN AS SOME POTENTIAL FOR ONGOING STORMS
OVER WRN IA/ERN NEB TO HOLD TOGETHER TODAY AND MOVE INTO DESTABILIZING
AIRMASS OVER OUR AREA.
&&
.PREV DISCUSSION... /ISSUED 845 PM EDT TUE MAY 1 2012/
UPDATE...
MADE ONLY MINOR TWEAKS TO NEAR TERM GRIDS WRT TEMPS AND POPS.
ADJUSTED TEMPS TO BETTER MATCH RECENT OBS AND TREND THROUGH THE
OVERNIGHT. REDUCED POPS FROM SOUTHWEST TO NORTHEAST AFTER 03Z AS
THE MCV OVER NORTHERN ILLINOIS SHOULD PULL THE WARM FRONT THROUGH
OUR REGION AND USHER DRIER CONDITIONS INTO MUCH OF THE FORECAST
AREA. REDUCED EMPHASIS OF THUNDER IN THE VERY NEAR TERM...BUT KEPT
THUNDER MENTION IN FOR THE OVERNIGHT AS SOME ELEVATED INSTABILITY
AND A STRENGTHENING LLJ COULD SPAWN A FEW THUNDERSTORMS ALONG THE
WARM FRONT THROUGH THE OVERNIGHT HOURS....ESPECIALLY ALONG THE
SOUTHERN TIER OF THE CWA WHERE STRONGEST MUCAPE EXISTS.
PREV DISCUSSION... /ISSUED 319 PM EDT TUE MAY 1 2012/
SHORT TERM...
MANY ISSUES TO SORT OUT IN THE SHORT TERM. MCV MOVING ACROSS THE
REGION TODAY HAS BEEN HANDLED BEST BY HRRR WITH OTHER HI RES
GUIDANCE IN BALLPARK BUT NOT NEAR AS FAST MOVING THIS WAVE
NORTHEAST. HAVE FOLLOWED HRRR FOR GUIDANCE IN THE SHORT TERM. SHOULD
SEE BULK OF PCPN MOVE EAST BEFORE 00Z WITH LINGERING SHOWERS AND FEW
THUNDERSTORMS FAR EAST AFTER 00Z. MEANWHILE...SOME DEVELOPMENT
POSSIBLE SOUTH OF MCV TRACK IN AREA OF INCREASING INSTABILITY LATE
THIS AFTERNOON WHICH COULD MOVE THROUGH CENTRAL AND NORTHERN AREAS
THIS EVENING. PREVIOUS GRIDS HAD LIKELY POPS ALL NIGHT AND THIS
SEEMS OVERDONE GIVEN FASTER ARRIVAL OF MCV AND INCREASING STABILITY
OVERNIGHT. HAVE ADJUSTED GRIDS FOR HIGHER POPS THIS EVENING BUT KEPT
CHANCE POPS OVERNIGHT WITH BOUNDARY IN THE AREA.
NEXT ISSUE IS WITH DEVELOPMENT OF AN MCS OVERNIGHT TO OUR NW AND
TRACK IT WOULD TAKE TOWARD DAYBREAK. NAM12 BRINGS SOUTHERN FRINGE OF
THIS SYSTEM ACROSS NORTHERN AREAS AROUND 12Z WITH GFS SIMILAR. HI
RES WRF NMM ALSO HINTS AT NORTHERN AREAS BEING BRUSHED BY CONVECTION
EARLY WED MORNING. THIS WARRANTS A SLIGHT NUDGE IN POPS EARLY
WEDNESDAY BUT CONFINED TO MID CHANCE RANGE GIVEN MCS UNCERTAINTY.
NAM AND WRF LAY A BOUNDARY OUT ACROSS CENTRAL CWA WEDNESDAY WHICH
THEN CONVECTS IN THE AFTERNOON WITH GROWING INSTABILITY. THIS
INSTABILITY IS CONTINGENT ON CLOUDS BREAKING UP AND AFTERNOON
HEATING BUT WITH SYNOPTIC WARM FRONT WELL NORTH AND STRONG SOUTHWEST
FLOW ALOFT THIS LOOKS PLAUSIBLE. RESULT WOULD BE TSRA DEVELOPMENT
FARTHER SOUTH IN CENTRAL CWA SO HAVE BROUGHT POPS BACK INTO THIS
AREA FOR THE AFTERNOON HOURS. SEVERE THUNDERSTORMS WOULD BE POSSIBLE
GIVEN MARGINAL BULK SHEAR BUT POTENTIALLY LARGE MUCAPE AND HIGH PWAT
VALUES.
TEMPS WILL BE VERY TRICKY WITH VERY WARM AND HUMID AIRMASS IN PLACE
BUT CONVECTIVE DEBRIS AND PCPN LIMITING FACTORS FOR MAX HEATING. ALL
BLEND USED FOR TEMPERATURES THROUGH THE SHORT TERM PERIOD AS THEY
ARE A NICE COMPROMISE BUT CERTAINLY COULD BE A LITTLE WARMER OR
COOLER DEPENDING ON AMOUNT OF SUN.
LONG TERM...THURSDAY THROUGH MONDAY
PERIOD TO BEGIN WITH SUBTLE HEIGHT RISES ACROSS THE UPPER
MIDWEST/NORTHERN GREAT LAKES AS MORE SIGNIFICANT SHORT WAVE UPPER
TROUGH AXIS TRACKS INTO THE PACIFIC NORTHWEST. THIS WILL RESULT IN
WARM FRONT TO CONTINUE TO SURGE NORTHWARD ACROSS THE GREAT LAKES
REGION ON THURSDAY. GENERALLY CAPPED CONDITIONS ARE ANTICIPATED
ACROSS APPROXIMATELY SOUTHERN TWO THIRDS OF THE FORECAST AREA WITH
MAIN QUESTION ON PRECIP CHANCES ACROSS THE FAR NORTH WHERE CAP WILL
LIKELY BE WEAKER. DIFFICULT AT THIS FORECAST DISTANCE TO LATCH ONTO
STRONGER PERIODS OF MID/UPPER LEVEL FORCING WITH MAIN SHORT WAVE
TRACK REMAINING WITH STRONGER BELT OF WESTERLIES FROM THE NORTHERN
PLAINS INTO THE UPPER GREAT LAKES. SEE NO REASON TO DEVIATE FROM
PREVIOUS FORECAST AT THIS TIME WITH LATE AFTERNOON LOW CHANCE TSRA
POPS ACROSS THE FAR NORTH GIVEN AFOREMENTIONED THERMODYNAMIC
PROFILES.
THE MORE PRONOUNCED PACIFIC WAVE IS THEN EXPECTED TO TRACK ACROSS
SOUTHWEST ONTARIO BY THURSDAY NIGHT INTO FRIDAY EVENTUALLY ALLOWING
COLD FRONT TO SHIFT EASTWARD. STRONGER FRONTAL CONVERGENCE MAY BE
CONFINED TO AREAS FURTHER NORTH ACROSS THE GREAT LAKES IN CLOSER
PROXIMITY TO STRONGER UPPER FORCING. HOWEVER WITH MODERATE
INSTABILITY PRECEDING THE FRONT WILL CONTINUE WITH MID RANGE
CHANCE POPS THURSDAY NIGHT THROUGH FRIDAY ACROSS ENTIRE FORECAST
AREA. SEVERE POTENTIAL STILL UNCLEAR FOR THURSDAY NIGHT/FRIDAY DUE
TO UNCERTAINTIES REGARDING UPSTREAM CONVECTION AND IMPACTS ON
INSTABILITY FOR THE LOCAL AREA ALONG WITH WHAT SHOULD BE MORE
MARGINAL DEEP LAYER SHEAR PROFILES FOR THIS PERIOD. NO SIGNIFICANT
CHANGES MADE TO VERY WARM TEMPERATURES IN ADVANCE OF THE FRONT
THURSDAY AFTERNOON WITH HIGHS IN THE MID TO UPPER 80S.
ON SATURDAY...ELONGATED SFC RIDGE AXIS TO BUILD INTO GREAT LAKES
REGION BEHIND THIS BOUNDARY...WITH SLIGHTLY MORE STABLE CONDITIONS.
PRECIP CHANCES ARE BECOMING MORE MUDDLED WITH BETTER ISENTROPIC
UPGLIDE OVER BOUNDARY POSSIBLY REMAINING JUST WEST OF THE AREA
ACROSS MID MS RVR VALLEY. CANNOT DISCOUNT ISOLD/SCT SHRA/TSRA
HOWEVER DUE TO PERSISTENT ELEVATED INSTABILITY. PERHAPS A SLIGHTLY
BETTER CHANCE FOR LATE SUNDAY/SUNDAY EVENING WHEN MID LEVEL RIDGE
IS EXPECTED TO SHIFT SLIGHTLY EASTWARD ACROSS CENTRAL CONUS IN
RESPONSE TO NEXT EASTERN PACIFIC WAVE MOVING ACROSS THE NORTHERN
ROCKIES. HOWEVER...BY LATE WEEKEND/EARLY NEXT WEEK MODEL
DETERMINISTIC/ENSEMBLE SPREADS BECOME MUCH MORE PRONOUNCED WITH
THIS NEXT PACIFIC WAVE. ALSO SIGNIFICANT VARIABILITY EXISTS WITH
EASTERN CANADIAN TROUGH THAT WILL IMPACT TRACK OF UPSTREAM PACIFIC
SYSTEM. GIVEN THESE UNCERTAINTIES...HAVE LOWERED CR ALLBLEND LOW
POPS TO BELOW MENTIONABLE LEVELS AND WILL KEEP MON/TUE DRY AT THIS
TIME.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...LASHLEY
LONG TERM...MARSILI
AVIATION...JT
UPDATE...BENTLEY
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1231 AM CDT WED MAY 2 2012
.AVIATION...
06Z TAFS FOR KOMA...KLNK...KOFK.
THUNDERSTORMS WILL AFFECT KOMA FOR A FEW HOURS EARLY THIS MORNING
AND AT LEAST BE IN THE KLNK VICINITY. SOME SCT TO BKN LOW CLOUDS
BELOW 1500 FEET ARE POSSIBLE THROUGH ABOUT 14Z THEN EXPECT AN
OVERALL INCREASE IN LOW LEVEL MOISTURE LATER TODAY. THUNDERSTORM
CHANCES WILL INCREASE AGAIN AFTER 00Z AT KOFK AND AFTER ABOUT 03Z
AT KOMA AND KLNK.
MILLER
&&
.PREV DISCUSSION... /ISSUED 341 PM CDT TUE MAY 1 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY
GOING FCST IS IN GOOD SHAPE...ONLY MINOR TWEAKS MADE. MAIN CONCERN
THEN CONTINUES TO BE PINNING DOWN AREAL COVERAGE OF SVR STORM
ACTIVITY THIS EVENING. AS OF NOW IT APPEARS THAT THE UPPER MIDWEST
WILL BE PRIME FOR SVR STORMS IN ASSOCIATED WITH LIFTING WARM FRONT...
WITH ANOTHER AREA OF RISK ASSOCIATED WITH COOL FRONT CURRENTLY
DROPPING THRU THE DAKOTAS. HRRR AND RAP SOLUTIONS HAVE BEEN RATHER
CONSISTENT TODAY SUGGESTING LINE OF CONVECTION MOVING INTO THE NRN
CWA BY EARLY EVENING. ESRH AROUND 360 M2/S2 AND MUCAPES 2000 J/KG OR
SO SHOULD BE ENOUGH TO POP SOME SVR MAINLY OVER NORTHEAST NEB.
AMPLIFYING TROF DIG OVER THE WRN CONUS WILL REPLACE THE NEAR-ZONAL
FLOW WITH LOW AMPLITUDE UPPER RIDGE GRADUALLY BUILDING OVER THE
PLAINS. THIS WILL ACT TO HINDER BNDRY PROGRESSION ANY FARTHER SOUTH
AND KEEP IT INVOF THE CWA. ON WEDNESDAY...MUCAPES INCREASE TO 4500
J/KG BY AFTERNOON BUT DEEP LAYER SHEAR IS MORE FOCUSED NORTH. THUS
NORTHEAST NEB MAY BE UNDER THE GUN AGAIN LATE WEDNESDAY
AFTN/EVENING. THURSDAY THROUGH FRIDAY MODELS PROG SEVERAL IMPULSES
EJECTING OUT OF THE SOUTHWESTERN STATES MAY HELP DESTABILIZE ENOUGH
TO POP OFF ADDITIONAL CONVECTION.
DEE
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
FAIRLY ACTIVE WEATHER PATTERN SHOULD CONTINUE INTO EARLY NEXT WEEK
AS UPPER TROUGH REMAIN TO OUR WEST...EJECTING WAVES OF ENERGY INTO
THE PLAINS.
WARM ADVECTION FRIDAY NIGHT MAY SPARK THUNDERSTORMS OVER THE
NORTHERN CWA...NORTH OF A EAST-WEST WARM FRONT BISECTING OUR AREA.
THOSE SHOULD MOVE ON OFF TO THE NORTHEAST FAIRLY QUICKLY SATURDAY
MORNING...LEAVING OUR CWA IN A VERY UNSTABLE AIRMASS BY SATURDAY
AFTERNOON. CAPPING UNDER WEAK MID LEVEL RIDGE MAY PRECLUDE
DEVELOPMENT MUCH OF THE DAY...MOST LIKELY WAITING FOR LOWERING
HEIGHTS AS RIDGE SLIDES EAST SATURDAY EVENING. THUNDERSTORMS ARE
GOOD BET THEN...ESPECIALLY IN THE NORTH WHERE A COLD FRONT WILL BE
APPROACHING OVERNIGHT.
THAT FRONT WILL DRIFT ACROSS THE AREA SUNDAY...MAINTAINING A FAIRLY
HIGH CHANCE FOR CONTINUING RAIN AND THUNDER. COOLER AIR WILL
FOLLOW...BUT THE CHANCE FOR RAIN OR SHOWERS WILL STILL EXIST AS
MOIST SOUTHWEST FLOW ALOFT RIDES OVER COOL SURFACE LAYER. THIS
PATTERN PERSISTS THROUGH TUESDAY.
TEMPERATURES LOOK WARM SATURDAY WITH SOUTHERLY FLOW AND MORE
HUMIDITY. HAVE HIGHS IN THE 80S THEN. RAIN AND COLD FRONTAL PASSAGE
WILL COOL HIGHS INTO THE 70S SUNDAY...THEN ONLY 60S FOR MONDAY AND
TUESDAY INFLUENCED BY NORTH TO EAST LOW LEVEL WIND COMPONENT.
DERGAN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1136 PM CDT TUE MAY 1 2012
.SHORT TERM...OVERNIGHT
1136 PM CDT TUE MAY 1 2012
STORMS ALONG THE INSTABILITY GRADIENT IN IOWA CONTINUE TO BE THE
DOMINANT STORMS WITH MUCH OF THE EARLIER CONVECTION IN EAST CENTRAL
MINNESOTA/WEST CENTRAL WISCONSIN WEAKENING OVER THE PAST FEW
HOURS. THE LOW LEVEL JET HAS STRENGTHENED AS WELL WHICH HAS LED TO
SOME ISOLATED TO SCATTERED CONVECTION DEVELOPING AHEAD OF THE LINE
OF STORMS THAT EXTENDS FROM SOUTH CENTRAL MINNESOTA INTO NORTH
CENTRAL IOWA. SOME WEAK INSTABILITY OF 500-1000 J/KG OF MUCAPE
CONTINUES TO FEED INTO THE LINE OF STORMS IN NORTH CENTRAL
IOWA...THOUGH THE 02.03Z RUC SHOWS THIS INSTABILITY DECREASING TO
THE EAST OVERNIGHT. CURRENT THINKING IS THAT THE LINE OF STORMS
WILL CONTINUE TO PROPAGATE EAST-SOUTHEAST ALONG THE NOSE OF THE
LOW LEVEL JET OVERNIGHT AND GRADUALLY WEAKEN. THUS...SOME GUSTY
WINDS AND HEAVY RAIN STILL CAN NOT BE RULED OUT ALONG WITH SOME
SMALL HAIL IN ANY ISOLATED STORMS OUT AHEAD OF THE LINE
OVERNIGHT. IF WINDS LIGHTEN UP BEHIND THE RAIN/STORMS...THEN SOME
FOG WILL BE POSSIBLE ACROSS THE REGION TOWARD DAYBREAK TOMORROW
MORNING.
.LONG TERM...SATURDAY THROUGH TUESDAY
255 PM CDT TUE MAY 1 2012
BROAD UPPER LEVEL RIDGING SLATED INTO EARLY NEXT WEEK...VIA THE
LATEST GFS AND ECMWF. BOTH STILL FAVOR BRINGING BITS OF UPPER LEVEL
ENERGY THROUGH THE RIDGE SAT/SUN...WITH SUN/SUN NIGHT HAVING THE
MOST AGREEMENT FOR PCPN CHANCES. SOLUTIONS START TO DIVERGE AS WE
WORK INTO MID WEEK. WILL GO WITH CONSENSUS. TEMPERATURES SHOULD
RETURN TO MORE SEASONABLE...EVEN A BIT BELOW NORMAL READINGS.
&&
.AVIATION...THROUGH 06Z THURSDAY
1136 PM CDT TUE MAY 1 2012
BUSY 24 HOUR PERIOD AT THE TAF SITES WITH STORMS MOVING IN OVER
THE NEXT FEW HOURS. GUSTY WINDS AND HEAVY RAINFALL WILL BE THE
MAIN THREATS AS THE STORMS MOVE IN OVERNIGHT. AHEAD OF THEM...A
1KFT TO 2KFT STRATUS DECK HAS MOVED IN ACROSS THE REGION AND WILL
LIKELY STAY IN PLACE OVERNIGHT. SOME ADDITIONAL FOG COULD DEVELOP
AFTER THE RAIN MOVES THROUGH IF WINDS WEAKEN BEFORE DAYBREAK.
GOING INTO THIS AFTERNOON...MORE THUNDERSTORMS WILL LIKELY DEVELOP
WITH MORE HEAVY RAIN...STRONG WINDS AND HAIL POSSIBLE. AS A COLD
FRONT MOVES THROUGH IN THE EVENING...THE RAIN AND THUNDER SHOULD
COME TO AN END.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
255 PM CDT TUE MAY 1 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....RIECK
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS DENVER CO
948 AM MDT WED MAY 2 2012
.UPDATE...SOUTHEAST WINDS HAVE BEEN CRANKING OVER SOUTHERN AND
EASTERN SECTIONS OF DENVER AREA AS WELL AS ALONG PALMER DIVIDE IN
RESPONSE TO LOCAL CYCLONE. WILL INCREASE WINDS IN THIS AREA FOR A
FEW HOURS WITH TREND TOWARD WEST AND NORTHWEST DURING AFTERNOON IN
LINE WITH LATEST RUC. BROAD UPPER TROUGH OVER NORTHERN ROCKIES
WITH SOME INCREASE IN LIFT ACROSS MOUNTAINS THROUGH THE DAY. BEST
CHANCE FOR SHOWERS AND STORMS TO BE ACROSS ZONES 31 AND 33 AND
HAVE INCREASED THE POPS THERE. REST OF FORECASTS LOOK IN ORDER FOR
NOW. LATEST RUC KEEPS SOME TYPE OF BOUNDARY SOUTH AND EAST OF
DENVER THROUGH THE AFTERNOON WHICH COULD BE A FOCUS FOR STORM
DEVELOPMENT. POTENTIAL FOR GUSTY OUTFLOW WITH STORMS.
PRECIPITATION AMOUNTS STILL LOOKING LIGHT WITH NO HYDROLOGIC
ISSUES ANTICIPATED.
&&
.AVIATION...SOUTHEAST WINDS CONTINUE TO CRANK AT APA AND DEN IN
RESPONSE TO CYCLONE OVER DENVER. RUC KEEPS THE SOUTHEASTERLY WINDS
THROUGH ABOUT 20Z AT DEN AND APA BEFORE GOING NORTHWEST...WILL
KEEP SOME SORT OF A SOUTHERLY COMPONENT THROUGH ABOUT 20Z.
OTHERWISE CURRENT TAFS STILL SEEM REASONABLE. STILL A SLIGHT
CHANCE FOR HIGH BASED SHOWERS OR STORMS VICINITY OF THE AIRPORTS
WITH GUST OUTFLOW WINDS THE MAIN IMPACT. VCSH SHOULD SUFFICE FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 400 AM MDT WED MAY 2 2012/
SHORT TERM...A BROAD UPPER TROUGH WILL BE PASSING OVER THE
NORTHERN ROCKIES TODAY. A JET STREAK ON THE FRONT OF THE TROUGH
CURRENTLY OVER WYOMING WILL MOVE EAST TO PUT COLORADO IN THE RIGHT
EXIT REGION. THIS AREA HAD KEPT ISOLATED THUNDERSTORMS GOING IN
NORTHEASTERN UTAH PAST MIDNIGHT LAST NIGHT. PRECIPITABLE WATER
VALUES ARE EXPECTED TO BE ABOUT THE SAME AS YESTERDAY BUT A LITTLE
MORE INSTABILITY AROUND...BETWEEN 150 AND 300 J/KG OF CAPE.
THEREFORE WILL BE EXPECTING SHOWERS AND THUNDERSTORMS TO BE A
LITTLE MORE WIDESPREAD ACROSS THE FORECAST AREA THIS AFTERNOON AND
EVENING. JUST LIKE YESTERDAY...THE MAIN IMPACT WILL BE GUSTY WINDS
OF UP TO 40 MPH AND LIGHT RAIN AMOUNTS. SLIGHT WARM ADVECTION WILL
BRING MAXIMUM TEMPERATURES A FEW DEGREES WARMER THAN YESTERDAY.
SOME MOISTURE TRANSPORTING IN WILL BRING SLIGHTLY HIGHER DEWPOINTS
AND THEREFORE SHOULD SEE HIGHER HUMIDITIES. A SURFACE TROUGH OVER
THE EASTERN PLAINS STRETCHING UP TO SOUTH DAKOTA WILL BRING
SOUTHERLY WINDS EARLY TODAY...THEN THE TROUGH WILL DEEPEN AND MOVE
OFF EAST WITH A WEAK FRONT MOVING SOUTH DOWN THE COLORADO PLAINS
TURNING WINDS NORTHERLY FOR A SHORT TIME. COULD SEE SOME STRATUS
OR PATCHY FOG AROUND OR EAST OF LIMON TONIGHT....BUT NOT ENOUGH
CONFIDENCE TO PUT IN THE FORECAST. OTHERWISE TONIGHT WILL BE
CALM...CLEAR AND SIMILAR TEMPERATURES TO LAST NIGHT.
LONG TERM...LOW LEVEL MOISTURE WILL INCREASE ACROSS THE PLAINS
THURSDAY WITH EAST/SOUTHEAST BOUNDARY LAYER FLOW ADVECTING IN
HIGHER DEWPOINTS FROM KANSAS. THIS WILL ALLOW A WEAK THETA-E RIDGE
TO DEVELOP ACROSS THE EASTERN PLAINS BY AFTERNOON WITH SURFACE
BASED CAPES NEAR 1000 J/KG. HOWEVER...AT THE SAME TIME THERE IS
VERY LITTLE OR NO SYNOPTIC SCALE LIFT/SHORTWAVE TO HELP DESTABILIZE
THE ATMOSPHERE. THEREFORE SEE LITTLE REASON TO CHANGE THE ONGOING
FORECAST OF LOW POPS FROM THE FRONT RANGE EASTWARD ACROSS THE
PLAINS.
BY FRIDAY...A DEEPER AND DRIER SOUTH/SOUTHWEST FLOW ALOFT WILL
DEVELOP OVER THE FORECAST AREA. THIS WILL PREVENT ANY CONVECTION
FROM DEVELOPING AND ALSO BRING UNSEASONABLY WARM CONDITIONS TO THE
FORECAST AREA. LOOKS LIKE HIGH TEMPS WILL REACH THE MID 80S ACROSS
THE PLAINS. RECORD FOR DENVER IS 87F SET IN 2000 AND WE SHOULD BE
WITHIN A COUPLE DEGREES OF THAT. FIRE DANGER WILL BE ELEVATED WITH
LOW HUMIDITIES AS WELL...BUT ANY EXTENT OF RED FLAG WARNINGS
SHOULD BE LIMITED BY GREEN FUELS OVER THE EASTERN PLAINS AND
LIGHTER WINDS ALONG THE FRONT RANGE. AT THIS TIME...MOST PRONE
AREA IS SHAPING UP TO BE SOUTH PARK WHERE HUMIDITIES DROP TO
AROUND 10 PERCENT WITH GUSTY WINDS POSSIBLE THERE.
FOR THE WEEKEND...A WEAK SURGE IS EXPECTED TO BACK ACROSS THE
PLAINS SATURDAY WITH VERY SLIGHT COOLING BUT AN INCREASE IN
MOISTURE. THIS WOULD LEAD TO A CHANCE OF STRONG THUNDERSTORMS OVER
THE NORTHEAST PLAINS LATE SATURDAY INTO SATURDAY NIGHT. SUNDAY
IS SHAPING UP TO BE COOLER AND MORE MOIST AS THE MAIN COLD FRONT
REACHES THE AREA. THIS SHOULD BRING MORE WIDESPREAD SHOWER AND
THUNDERSTORM COVERAGE BY SUNDAY AFTERNOON AND SUNDAY NIGHT.
SHOWERS AND A FEW THUNDERSTORMS WILL LIKELY REMAIN IN THE AREA
THROUGH THE FIRST HALF OF NEXT WEEK WITH A SLOW MOVING UPPER
TROUGH OVER THE REGION. LAST 3 RUNS OF THE ECMWF HAVE FLIP-FLOPPED
REGARDING WHETHER WE WILL SEE A 4 CORNERS LOW OR JUST A SLOW MOVING
UPPER LEVEL TROUGH...WHILE THE LATEST GFS ENSEMBLES ARE AVERAGING
TOWARD A SLOW MOVING TROUGH. NONETHELESS...EARLY NEXT WEEK SHOULD
FEATURE A MUCH BETTER CHANCE OF MEANINGFUL PRECIPITATION AND BELOW
NORMAL TEMPERATURES.
AVIATION...DRAINAGE WINDS WILL BE SLOWLY TRANSITIONING TO THE
WEST LATE AFTERNOON...WITH A FRONT EXPECTED TO MOVE THROUGH THE
AREA AIRPORTS AFTER 20Z. A SLIGHT CHANCE OF HIGH BASED SHOWERS OR
THUNDERSTORMS NEAR THE AIRPORTS LATE THIS AFTERNOON...MAIN IMPACT
WILL BE GUSTY OUTFLOW WINDS.
HYDROLOGY...A SLIGHT CHANCE OF A SHOWER OR STORM TO MOVE OVER THE
BURN AREA THIS AFTERNOON OR EVENING. MAIN IMPACT WILL BE
WIND...WITH ONLY UP TO A TENTH OF AN INCH OF PRECIPITATION AT
MOST.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....BARJENBRUCH
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
1040 AM EDT WED MAY 2 2012
.UPDATE (REST OF TODAY AND TONIGHT)...
14Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW A RATHER
UNAMPLIFIED UPPER LEVEL PATTERN ACROSS THE CONUS. NORTHERN STREAM
FLOW SHOWS SLIGHT TROUGHING OVER THE INTER-MOUNTAIN WEST BEFORE
BENDING BACK TO THE NORTH INTO LONGWAVE RIDGING FROM THE GREAT LAKES
TO NEW ENGLAND/QUEBEC. ONE SUBTLE SHORTWAVE WITHIN THE FLOW IS NOW
PASSING THROUGH THE UPPER MS VALLEY AND FORCING SEVERAL AREA OF
SHOWERS AND STORMS ACROSS THE GREAT LAKES REGION. CLOSER TO HOME WE
FIND BROAD UPPER LEVEL RIDGING IN PLACE OVER THE SOUTHEASTERN
STATES. 12Z KTBW SOUNDING PROFILE IS NOT ALL THAT UNFAVORABLE TO
SUPPORT DEEP CONVECTION. THE PW VALUE IS AT 1.5"...WHICH IS ACTUALLY
QUITE A BIT ABOVE NORMAL FOR EARLY MAY. MID-LEVEL THETA-E VALUES ARE
NOT ALL THAT IMPRESSIVE...BUT ALSO NOT COMPLETELY HOSTILE TO DEEP
CONVECTION WITH VALUES RANGING BETWEEN 322-325K.
AT THE SURFACE...FORECAST AREA RESIDES WITHIN A REGION OF LOW LEVEL
SOUTHEASTERLY FLOW ON THE SOUTHERN SIDE OF THE SUBTROPICAL RIDGE
AXIS. GRADIENT IS NOT AS TIGHT AS PREVIOUS DAYS...AND WITH GOOD
DIURNAL HEATING INLAND...WE SHOULD BE ABLE TO DEVELOP SEA-BREEZE
CIRCULATION LATE IN THE DAY. THE EASTERLY COMPONENT TO THE SYNOPTIC
FLOW HOWEVER WILL KEEP THESE SEA-BREEZES PINNED CLOSE TO THE
COAST...WITH LITTLE INLAND PROPAGATION.
ALREADY SEEING A QUICK DEVELOPMENT OF TODAY`S CU FIELD...SO A PARTLY
CLOUDY FORECAST WILL GO AHEAD THROUGH THE REMAINDER OF THE DAY. 850
MB TEMPS IN THE 14-16C RANGE SHOULD MIX OUT TO AROUND 90 INLAND BY
LATE AFTERNOON. THE DEVELOPING ONSHORE FLOW WILL HOLD TEMPS DOWN A
FEW DEGREES AT THE BEACHES...HOWEVER THE LATE START TO THE
SEA-BREEZES SHOULD STILL ALLOW TEMPS TO REACH THE MID/UPPER 80S. DUE
TO NOT UNFAVORABLE THERMODYNAMICS IN PLACE...IT IS NO SURPRISE THAT
MANY OF THE PARAMETRIZED AND CONVECTION ALLOWING GUIDANCE ARE
SHOWING SCT SHOWER/STORMS DEVELOPMENT ALONG THE SEA-BREEZE LATE THIS
AFTERNOON/ EARLY EVENING. AS MENTIONED ABOVE...THE SEA-BREEZE WILL
BE HELD CLOSE TO THE COAST AND HENCE SO WILL THE BEST LOW LEVEL
FOCUS FOR ASCENT. CONVECTION THAT DOES FIRE NEAR THE COAST WILL
GENERALLY DRIFT BACK TO THE WEST/WNW WITH THE DEEP LAYER FLOW...AND
THEREFORE HAVE THE HIGHEST POPS (~40%) ALONG ALL THE COASTAL
ZONES...AND THEN TAPER RAIN CHANCES DOWN AS ONE TRAVELS INLAND. THIS
REPRESENTS AN INCREASE IN THE RAIN CHANCES ALONG THE NATURE COAST
ZONES FROM THE EARLIER FORECAST.
LINGERING SHOWERS/STORMS SHOULD PUSH OFFSHORE INTO THE EASTERN GULF
DURING THE MIDDLE/LATER EVENING HOURS. THE REMAINDER OF THE
OVERNIGHT LOOKS QUIET...DRY AND WARM. LOW TEMPERATURES BY SUNRISE
THURSDAY MORNING LOOK TO RANGE FROM THE MIDDLE 60S IN THE INTERIOR
COOL SPOTS TO THE LOWER 70S ALONG THE COAST. HAVE A GREAT DAY!
&&
.AVIATION...
VFR WITH SOME BRIEF MVFR CEILINGS THIS MORNING...THEN SEA BREEZE
SHOWERS AND THUNDERSTORMS MAINLY AFTER 18Z.
&&
.MARINE...
ELEVATED WINDS AND SEAS WILL DIMINISH VERY EARLY IN THE PERIOD AS
THE SMALL CRAFT ADVISORY COMES TO AN END. SURFACE LOW PRESSURE
WILL PUSH WELL WEST OF THE AREA INTO THE OPEN GULF OF MEXICO AND
SEAS WILL SUBSIDE TODAY AS WELL. HIGH PRESSURE BUILDING INTO THE
AREA FROM THE ATLANTIC WILL KEEP A MODERATE EASTERLY FLOW IN PLACE
THROUGH FRIDAY WITH SLIGHTLY ELEVATED WINDS AND SEAS...THEN AS THE
RIDGE BUILDS OVER THE AREA ON SATURDAY AND SUNDAY LIGHT WINDS WILL
OCCUR. AFTERNOON SEA BREEZES NEAR THE COAST ARE EXPECTED THE NEXT
FEW DAYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 90 71 89 71 / 40 20 15 10
FMY 89 69 90 68 / 30 10 15 10
GIF 90 67 89 65 / 10 10 10 10
SRQ 89 70 86 67 / 40 20 15 10
BKV 90 65 90 63 / 35 15 10 10
SPG 86 75 86 73 / 40 20 15 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1047 AM EDT WED MAY 2 2012
.SYNOPSIS...
WARM SOUTHERLY FLOW WILL PERSIST INTO THE WEEKEND. UPPER
DISTURBANCES WILL BRING CHANCES OF SHOWERS AND THUNDERSTORMS
MOSTLY TOWARDS THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SKIES HAVE CLEARED ACROSS MOST OF THE AREA. THERE WAS SOME ACCAS
ACROSS THE SOUTHERN ZONES EARLIER INDICATING MID LEVEL INSTABILITY
IN PLACE. STRONG HEATING WILL TAKE PLACE WHICH WILL RESULT
CONSIDERABLE INSTABILITY. RAP AND HRRR RUNS SUGGEST THAT
SCATTERED STORMS WILL DEVELOP MAINLY ACROSS THE SOUTHERN COUNTIES
AS A WEAK DISTURBANCE MOVES THROUGH THE FLOW. SHEAR WILL BE WEAK
SO STORMS SHOULD BE DISORGANIZED. BUT GIVEN FORECAST INSTABILITY
CANNOT RULE OUT ISOLATED SEVERE STORMS.
ALSO HAVE TO WATCH FAR NORTHERN COUNTIES LATE IN THE DAY. OUTFLOW
BOUNDARY FROM EARLIER CONVECTION TO THE NORTHWEST WILL APPROACH
THE REGION AND SERVE AS A FOCUS FOR MORE STORMS. IT IS MORE A
QUESTION OF WHETHER THEY WILL WORK AS FAR SOUTH AS THE FORECAST
AREA. SHEAR WILL BE SOMEWHAT BETTER IN THAT REGION.
WINDS WILL BECOME GUSTY AS INVERSION BREAKS. FORECAST TEMPERATURES
LOOK REASONABLE AT THIS POINT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
WHILE THE SMALL THREAT FOR SHOWERS AND STORMS SHOULD END FOR MOST
OF THE CWA DURING THE EVENING...A WEAK SHORTWAVE FOLLOWING THE
CREST OF THE RIDGE THROUGH MICHIGAN WILL EVENTUALLY TURN SLIGHTLY
SOUTHEASTWARD...MOVING INTO EASTERN OHIO AND PENNSYLVANIA BY LATE
IN THE EVENING. THE PROBABILITY OF A SIGNIFICANT AMOUNT OF THIS
ACTIVITY MAKING IT INTO THE FORECAST AREA IS SOMEWHAT
LIMITED...GIVEN THAT IT WILL BE FIGHTING THE RIDGING AND A BIT OF
BOUNDARY LAYER STABILIZATION BY THAT POINT IN THE DAY. COMBINED
WITH MARGINAL SHEAR...THE SEVERE THREAT DOES NOT SEEM TO BE
TERRIBLY HIGH HERE...BUT A FEW STRONG STORMS MAY BE POSSIBLE.
RIDGING WILL BE INCREASING IN STRENGTH BY THURSDAY...LEADING TO A
LESS LIKELY SCENARIO FOR POP UP STORM DEVELOPMENT. THUS...A DRY
FORECAST WILL BE MAINTAINED AT THIS TIME...ALTHOUGH THE VERY WARM
AND POTENTIALLY UNSTABLE CONDITIONS KEEP THIS FROM BEING IN THE
HIGHEST LEVELS OF CONFIDENCE. WHAT THURSDAY WILL BRING...ON MORE
STRONG WARM ADVECTION AND ANOTHER DAY OF SUN...IS HIGH
TEMPERATURES THAT WILL COME CLOSE TO RECORD VALUES.
A SHORTWAVE WILL BE MOVING TOWARD THE AREA ON FRIDAY...FINALLY
PROVIDING A BIT OF FOCUS FOR CONVECTION. WITH INCREASED CHANCES OF
STORMS (POSSIBLY STRONG) ON FRIDAY...AND EARLIER TIMING THAN
PREVIOUSLY FORECAST...TEMPERATURES WERE REDUCED SLIGHTLY. THE
HIGHEST TEMPS WILL STILL BE IN THE SOUTHEAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
FOR SATURDAY AND SUNDAY...THE PRIMARY THREAT FOR THUNDERSTORMS
WILL SHIFT SOUTH NEAR THE OHIO RIVER AS THE BOUNDARY BECOMES
NEARLY STATIONARY OVER KENTUCKY.
A CHANCE OF THUNDERSTORMS WILL OVERSPREAD THE AREA BY LATE MONDAY AS
A STRONGER DISTURBANCE MOVES ALONG THE NORTHERN PERIPHERY OF THE
UPPER RIDGE. WEAK HIGH PRESSURE AND DRIER WEATHER MAY ENTER THE
PICTURE ON TUESDAY.
HIGHS UP IN THE 80S THURSDAY AND FRIDAY WILL SLIP BACK TOWARD NORMAL
READINGS AROUND 70 BY TUESDAY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
A WARM FRONT WILL LIFT NORTH INTO THE LOWER GREAT LAKES THROUGH
THIS MORNING. MID LVL RIDGE WILL THEN BUILD NORTHWARD INTO THE
OHIO VALLEY. REGION SHOULD BE WARM SECTORED AND CHANCES FOR
SHOWERS AND STORMS WILL BE MINIMAL AND HAVE THUS LEFT OUT OF THE
TAFS. MODEST PRESSURE GRADIENT AND DAYTIME MIXING WILL ALLOW WINDS
TO INCREASE FROM THE SOUTHWEST WITH SOME GUSTS UP TO 25 KNOTS
DURING THE AFTERNOON.
FOR TONIGHT...AN UPPER LEVEL WEATHER DISTURBANCE IS FORECAST TO
TRACK EASTWARD ACROSS THE LOWER GREAT LAKES. AT THIS TIME...IT
APPEARS THE MAIN CONVECTIVE ACTIVITY WILL REMAIN NORTH OF THE TAF
SITES...BUT SHORT TERM MESOSCALE TRENDS WILL HAVE TO BE MONITOR
SHOULD IT SLIDE FARTHER SOUTH INTO THE AREA. HAVE KEPT THE
FORECAST DRY AT THE TAF SITES TONIGHT ATTM.
OUTLOOK...THUNDERSTORMS POSSIBLE FRIDAY INTO SATURDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...HATZOS
LONG TERM...CONIGLIO
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS DENVER CO
1017 AM MDT WED MAY 2 2012
.AVIATION...LOOKS LIKE SOUTHEAST WINDS WILL CONTINUE ACROSS APA
AND DEN THROUGH AT LEAST 20Z WITH SOME GUSTS TO 30 KTS. UPCOMING
ISSUANCE WILL REFLECT THE LATEST THINKING. ALL ELSE SEEMS IN ORDER
FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 948 AM MDT WED MAY 2 2012/
UPDATE...SOUTHEAST WINDS HAVE BEEN CRANKING OVER SOUTHERN AND
EASTERN SECTIONS OF DENVER AREA AS WELL AS ALONG PALMER DIVIDE IN
RESPONSE TO LOCAL CYCLONE. WILL INCREASE WINDS IN THIS AREA FOR A
FEW HOURS WITH TREND TOWARD WEST AND NORTHWEST DURING AFTERNOON IN
LINE WITH LATEST RUC. BROAD UPPER TROUGH OVER NORTHERN ROCKIES
WITH SOME INCREASE IN LIFT ACROSS MOUNTAINS THROUGH THE DAY. BEST
CHANCE FOR SHOWERS AND STORMS TO BE ACROSS ZONES 31 AND 33 AND
HAVE INCREASED THE POPS THERE. REST OF FORECASTS LOOK IN ORDER FOR
NOW. LATEST RUC KEEPS SOME TYPE OF BOUNDARY SOUTH AND EAST OF
DENVER THROUGH THE AFTERNOON WHICH COULD BE A FOCUS FOR STORM
DEVELOPMENT. POTENTIAL FOR GUSTY OUTFLOW WITH STORMS.
PRECIPITATION AMOUNTS STILL LOOKING LIGHT WITH NO HYDROLOGIC
ISSUES ANTICIPATED.
AVIATION...SOUTHEAST WINDS CONTINUE TO CRANK AT APA AND DEN IN
RESPONSE TO CYCLONE OVER DENVER. RUC KEEPS THE SOUTHEASTERLY WINDS
THROUGH ABOUT 20Z AT DEN AND APA BEFORE GOING NORTHWEST...WILL
KEEP SOME SORT OF A SOUTHERLY COMPONENT THROUGH ABOUT 20Z.
OTHERWISE CURRENT TAFS STILL SEEM REASONABLE. STILL A SLIGHT
CHANCE FOR HIGH BASED SHOWERS OR STORMS VICINITY OF THE AIRPORTS
WITH GUST OUTFLOW WINDS THE MAIN IMPACT. VCSH SHOULD SUFFICE FOR NOW.
PREV DISCUSSION... /ISSUED 400 AM MDT WED MAY 2 2012/
SHORT TERM...A BROAD UPPER TROUGH WILL BE PASSING OVER THE
NORTHERN ROCKIES TODAY. A JET STREAK ON THE FRONT OF THE TROUGH
CURRENTLY OVER WYOMING WILL MOVE EAST TO PUT COLORADO IN THE RIGHT
EXIT REGION. THIS AREA HAD KEPT ISOLATED THUNDERSTORMS GOING IN
NORTHEASTERN UTAH PAST MIDNIGHT LAST NIGHT. PRECIPITABLE WATER
VALUES ARE EXPECTED TO BE ABOUT THE SAME AS YESTERDAY BUT A LITTLE
MORE INSTABILITY AROUND...BETWEEN 150 AND 300 J/KG OF CAPE.
THEREFORE WILL BE EXPECTING SHOWERS AND THUNDERSTORMS TO BE A
LITTLE MORE WIDESPREAD ACROSS THE FORECAST AREA THIS AFTERNOON AND
EVENING. JUST LIKE YESTERDAY...THE MAIN IMPACT WILL BE GUSTY WINDS
OF UP TO 40 MPH AND LIGHT RAIN AMOUNTS. SLIGHT WARM ADVECTION WILL
BRING MAXIMUM TEMPERATURES A FEW DEGREES WARMER THAN YESTERDAY.
SOME MOISTURE TRANSPORTING IN WILL BRING SLIGHTLY HIGHER DEWPOINTS
AND THEREFORE SHOULD SEE HIGHER HUMIDITIES. A SURFACE TROUGH OVER
THE EASTERN PLAINS STRETCHING UP TO SOUTH DAKOTA WILL BRING
SOUTHERLY WINDS EARLY TODAY...THEN THE TROUGH WILL DEEPEN AND MOVE
OFF EAST WITH A WEAK FRONT MOVING SOUTH DOWN THE COLORADO PLAINS
TURNING WINDS NORTHERLY FOR A SHORT TIME. COULD SEE SOME STRATUS
OR PATCHY FOG AROUND OR EAST OF LIMON TONIGHT....BUT NOT ENOUGH
CONFIDENCE TO PUT IN THE FORECAST. OTHERWISE TONIGHT WILL BE
CALM...CLEAR AND SIMILAR TEMPERATURES TO LAST NIGHT.
LONG TERM...LOW LEVEL MOISTURE WILL INCREASE ACROSS THE PLAINS
THURSDAY WITH EAST/SOUTHEAST BOUNDARY LAYER FLOW ADVECTING IN
HIGHER DEWPOINTS FROM KANSAS. THIS WILL ALLOW A WEAK THETA-E RIDGE
TO DEVELOP ACROSS THE EASTERN PLAINS BY AFTERNOON WITH SURFACE
BASED CAPES NEAR 1000 J/KG. HOWEVER...AT THE SAME TIME THERE IS
VERY LITTLE OR NO SYNOPTIC SCALE LIFT/SHORTWAVE TO HELP DESTABILIZE
THE ATMOSPHERE. THEREFORE SEE LITTLE REASON TO CHANGE THE ONGOING
FORECAST OF LOW POPS FROM THE FRONT RANGE EASTWARD ACROSS THE
PLAINS.
BY FRIDAY...A DEEPER AND DRIER SOUTH/SOUTHWEST FLOW ALOFT WILL
DEVELOP OVER THE FORECAST AREA. THIS WILL PREVENT ANY CONVECTION
FROM DEVELOPING AND ALSO BRING UNSEASONABLY WARM CONDITIONS TO THE
FORECAST AREA. LOOKS LIKE HIGH TEMPS WILL REACH THE MID 80S ACROSS
THE PLAINS. RECORD FOR DENVER IS 87F SET IN 2000 AND WE SHOULD BE
WITHIN A COUPLE DEGREES OF THAT. FIRE DANGER WILL BE ELEVATED WITH
LOW HUMIDITIES AS WELL...BUT ANY EXTENT OF RED FLAG WARNINGS
SHOULD BE LIMITED BY GREEN FUELS OVER THE EASTERN PLAINS AND
LIGHTER WINDS ALONG THE FRONT RANGE. AT THIS TIME...MOST PRONE
AREA IS SHAPING UP TO BE SOUTH PARK WHERE HUMIDITIES DROP TO
AROUND 10 PERCENT WITH GUSTY WINDS POSSIBLE THERE.
FOR THE WEEKEND...A WEAK SURGE IS EXPECTED TO BACK ACROSS THE
PLAINS SATURDAY WITH VERY SLIGHT COOLING BUT AN INCREASE IN
MOISTURE. THIS WOULD LEAD TO A CHANCE OF STRONG THUNDERSTORMS OVER
THE NORTHEAST PLAINS LATE SATURDAY INTO SATURDAY NIGHT. SUNDAY
IS SHAPING UP TO BE COOLER AND MORE MOIST AS THE MAIN COLD FRONT
REACHES THE AREA. THIS SHOULD BRING MORE WIDESPREAD SHOWER AND
THUNDERSTORM COVERAGE BY SUNDAY AFTERNOON AND SUNDAY NIGHT.
SHOWERS AND A FEW THUNDERSTORMS WILL LIKELY REMAIN IN THE AREA
THROUGH THE FIRST HALF OF NEXT WEEK WITH A SLOW MOVING UPPER
TROUGH OVER THE REGION. LAST 3 RUNS OF THE ECMWF HAVE FLIP-FLOPPED
REGARDING WHETHER WE WILL SEE A 4 CORNERS LOW OR JUST A SLOW MOVING
UPPER LEVEL TROUGH...WHILE THE LATEST GFS ENSEMBLES ARE AVERAGING
TOWARD A SLOW MOVING TROUGH. NONETHELESS...EARLY NEXT WEEK SHOULD
FEATURE A MUCH BETTER CHANCE OF MEANINGFUL PRECIPITATION AND BELOW
NORMAL TEMPERATURES.
AVIATION...DRAINAGE WINDS WILL BE SLOWLY TRANSITIONING TO THE
WEST LATE AFTERNOON...WITH A FRONT EXPECTED TO MOVE THROUGH THE
AREA AIRPORTS AFTER 20Z. A SLIGHT CHANCE OF HIGH BASED SHOWERS OR
THUNDERSTORMS NEAR THE AIRPORTS LATE THIS AFTERNOON...MAIN IMPACT
WILL BE GUSTY OUTFLOW WINDS.
HYDROLOGY...A SLIGHT CHANCE OF A SHOWER OR STORM TO MOVE OVER THE
BURN AREA THIS AFTERNOON OR EVENING. MAIN IMPACT WILL BE
WIND...WITH ONLY UP TO A TENTH OF AN INCH OF PRECIPITATION AT
MOST.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....BARJENBRUCH
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
200 PM EDT WED MAY 2 2012
.SYNOPSIS...
18Z WATER VAPOR AND H4 RUC ANALYSIS CONTINUES TO SHOW A RATHER
UNAMPLIFIED UPPER LEVEL PATTERN ACROSS THE CONUS. NORTHERN STREAM
FLOW SHOWS SLIGHT TROUGHING OVER THE INTER-MOUNTAIN WEST BEFORE
BENDING BACK TO THE NORTH INTO LONGWAVE RIDGING FROM THE GREAT LAKES
TO NEW ENGLAND/QUEBEC. CLOSER TO HOME WE FIND BROAD UPPER LEVEL
RIDGING IN PLACE OVER THE SOUTHEASTERN STATES. 12Z KTBW SOUNDING
PROFILE IS NOT ALL THAT UNFAVORABLE TO SUPPORT DEEP CONVECTION. THE
PW VALUE IS AT 1.5"...WHICH IS ACTUALLY QUITE A BIT ABOVE NORMAL FOR
EARLY MAY. MID-LEVEL THETA-E VALUES ARE NOT ALL THAT IMPRESSIVE...
BUT ALSO NOT COMPLETELY HOSTILE TO DEEP CONVECTION WITH VALUES
RANGING BETWEEN 321-324K.
AT THE SURFACE...FORECAST AREA RESIDES WITHIN A REGION OF LOW LEVEL
SOUTHEASTERLY FLOW ON THE SOUTHERN SIDE OF THE SUBTROPICAL RIDGE
AXIS. GRADIENT IS NOT AS TIGHT AS PREVIOUS DAYS...HOWEVER STILL
EXPERIENCING MODERATE OFFSHORE FLOW THIS AFTERNOON. BIG FORECAST
QUESTION OVER THE NEXT SEVERAL HOURS WILL BE IF DIURNAL HEATING
INLAND WILL BE ENOUGH TO FORCE SEA-BREEZE DEVELOPMENT AND GIVE US A
SHOT AT SCT EARLY EVENING CONVECTION. IF A FEEBLE SEA-BREEZE CAN
DEVELOP LATER THIS AFTERNOON...THE EASTERLY COMPONENT TO THE
SYNOPTIC FLOW WILL CERTAINLY PIN THE CIRCULATION VERY CLOSE TO THE
COAST...WITH LITTLE INLAND PROPAGATION.
&&
.SHORT TERM (REST OF THIS AFTERNOON THROUGH FRIDAY)...
THROUGH EARLY EVENING...AS MENTIONED ABOVE...DIFFICULT FORECAST IN
WHETHER OR NOT A FEEBLE SEABREEZE WILL ESTABLISH ITSELF AT THE COAST
OVER THE NEXT FEW HOURS. LATEST OBSERVATIONS MAKE THIS VERY
QUESTIONABLE WITH 15+ KNOT OFFSHORE GUSTS STILL BEING REPORTED AT
THE COAST. HOWEVER...MOST OF THE GUIDANCE STILL SHOWS THIS FLOW
BREAKING DOWN BY 21Z. ALSO...DUE TO NOT UNFAVORABLE THERMODYNAMICS
IN PLACE...IT IS NO SURPRISE THAT MANY OF THE PARAMETRIZED AND
CONVECTION ALLOWING 12Z GUIDANCE CONTINUE TO SHOWING THE CONVECTIVE
DEVELOPMENT EARLY THIS EVENING. WITH TO THE SEA-BREEZE BEING HELD
CLOSE TO THE COAST...SO WILL THE BEST LOW LEVEL FOCUS FOR ASCENT.
CONVECTION THAT DOES FIRE NEAR THE COAST WILL GENERALLY DRIFT BACK
TO THE WEST/WNW WITH THE DEEP LAYER FLOW...AND THEREFORE HAVE THE
HIGHEST POPS (~40%) ALONG ALL THE COASTAL ZONES...AND THEN TAPER
RAIN CHANCES DOWN AS ONE TRAVELS INLAND. WILL NOT MAKE ANY DRASTIC
CHANGES TO THE FORECAST...BUT WILL PULL THE CHANCES FOR SCT
SHOWER/STORMS EVEN CLOSER TO THE COAST THAN WAS PREVIOUSLY DRAWN.
TONIGHT...LINGERING SHOWERS/STORMS SHOULD PUSH OFFSHORE INTO THE
EASTERN GULF DURING THE MIDDLE/LATER EVENING HOURS. THE REMAINDER OF
THE OVERNIGHT LOOKS QUIET...DRY AND WARM. LOW TEMPERATURES BY
SUNRISE THURSDAY MORNING LOOK TO RANGE FROM THE MIDDLE 60S IN THE
INTERIOR COOL SPOTS TO THE LOWER 70S ALONG THE COAST.
THURSDAY...SHORTWAVE ENERGY IS PROGGED TO BE APPROACHING AL/GA/FL
PANHANDLE DURING THE DAY. THIS SYNOPTIC SUPPORT LOOKS TO REMAIN
REMOVED TO THE NW OF OUR ZONES AND THEREFORE WILL LIKELY BE AN
ENHANCEMENT TO CONVECTIVE POTENTIAL ONLY TO AREA NORTH AND WEST OF
THE FLORIDA BIG BEND. FOR OUR FORECAST AREA...STACKED RIDGING WILL
REMAIN IN CONTROL WITH AN EVEN DRIER COLUMN BUILDING IN FROM THE
EAST. AT THE SURFACE...THE SUBTROPICAL RIDGE AXIS WILL BUILD
SOUTHWARD SOMEWHAT ALLOWING A LIGHTER GRADIENT AND WEAKER SYNOPTIC
EASTERLY FLOW. THIS WEAKER FLOW WILL ALMOST CERTAINLY ALLOW THE
DEVELOPMENT OF WELL-DEFINED SEA-BREEZE CIRCULATIONS DURING THE
AFTERNOON. HOWEVER...THE THERMODYNAMICS BECOME QUITE HOSTILE TO DEEP
CONVECTION WITH MID-LEVEL THETA-E VALUES DROPPING BELOW 320K. NEVER
WANT TO COMPLETELY RULE OUT A CONVECTIVE ELEMENT THAT CAN OVERCOME
THE NEGATIVE FACTORS...BUT FEEL ANY COVERAGE ON THURSDAY WILL BE LOW
ENOUGH TO KEEP MENTION OUT OF THE FORECAST. WILL ONLY DRAW A 10%
SILENT POP IN THE GRIDS. HOT DAY IN THE FORECAST WITH TEMPERATURES
PUSHING THE LOWER 90S INLAND AND IN THE 80S AT THE BEACHES DUE TO
THE DEVELOPING ONSHORE FLOW.
FRIDAY...ANOTHER MAINLY DRY AND WARM DAY TO END OUT THE WORKWEEK.
WEAK RESIDUAL SYNOPTIC ENERGY FROM THE SHORTWAVE CROSSING THE
SOUTHEASTERN STATES WILL MAKE ITS CLOSEST APPROACH TO OUR NORTHERN
ZONES DURING THE DAY AND MAY BE JUST ENOUGH TO FORCE A FEW ISOLATED
SHOWERS. WILL DRAWN IN A SLIGHT CHANCE 15-20% POP FOR AREAS
GENERALLY NORTH OF CRYSTAL RIVER DURING THE AFTERNOON...BUT
ELSEWHERE WILL LEAVE RAIN MENTION OUT OF THE FORECAST AS
THERMODYNAMICS REMAIN QUITE HOSTILE TO DEEP CONVECTION.
&&
.LONG TERM (SATURDAY THROUGH TUESDAY)...
THE GLOBAL MODELS ARE GENERALLY CONSISTENT ALTHOUGH THERE ARE SOME
MINOR DIFFERENCES IN LOCATION...TIMING AND SMALL FEATURES. AN UPPER
RIDGE FROM THE WESTERN GULF TO THE GREAT LAKES WITH A TROUGH OFF THE
EASTERN BOARD DOWN TO THE BAHAMAS AND EASTERN CUBA FRIDAY NIGHT
SLOWLY WORKS EAST. AT THE SURFACE HIGH PRESSURE FROM THE GULF TO THE
ATLANTIC...WITH AN AXIS INITIALLY ACROSS NORTH/CENTRAL FL...SAGS
SOUTHWARD AS A WEAK FRONTAL BOUNDARY MOVES FROM THE SE U.S. COASTAL
WATERS INTO THE STATE MON AND TUE.
WILL KEEP THE CURRENT FORECAST TREND FOR NOW. PARTLY CLOUDY WITH A
SLIGHT CHANCE OF DAYTIME THUNDERSTORMS...MAINLY IN THE AFTERNOONS.
THE FRONTAL BOUNDARY MON/TUE WOULD SUGGEST SLIGHTLY MORE COVERAGE
OF PRECIPITATION. HOWEVER HAVE LIMITED POPS TO JUST SLIGHT CHANCE...
CLOSER TO CLIMO AND BELOW SOME OF THE MEX GUIDANCE. TEMPERATURES
WILL BE NEAR OR JUST ABOVE NORMAL...BY PERHAPS A COUPLE OF DEGREES
AT TIMES. AS THE RIDGE AXIS SHIFTS SOUTH ACROSS THE AREA WINDS WILL
BE LIGHT WITH SEA BREEZE CIRCULATIONS FOR THE AFTERNOONS.
&&
.AVIATION...
MAINLY VFR WITH SOME CHANCE OF ISOLATED TO SCATTERED LATE AFTERNOON
AND EVENING STORMS NEAR COASTAL TERMINALS. COULD ALSO SEE BRIEF MVFR
CEILINGS AGAIN AFTER SUNRISE THURSDAY BUT CONFIDENCE TOO LOW TO PUT
IN TAFS AT THIS TIME.
&&
.MARINE...
NEAR CAUTIONARY LEVEL FLOW WILL CONTINUE OVERNIGHT...ESPECIALLY FROM
TAMPA BAY SOUTHWARD AND THEN DIMINISH QUICKLY ON THURSDAY BELOW
HEADLINE CRITERIA. THE SUBTROPICAL RIDGE AXIS WILL THEN BUILD
SOUTHWARD OVER THE AREA DURING THE LATER PORTION OF THE WEEK AND
HELP KEEP WINDS AND SEAS LOW THROUGH SATURDAY.
&&
.FIRE WEATHER...
NO SIGNIFICANT FIRE WEATHER CONCERNS EXPECTED THROUGH THE REST OF
THE WEEK. RELATIVE HUMIDITY VALUES ARE FORECAST TO BRIEFLY APPROACH
CRITICAL VALUES OVER INTERIOR ZONES THE NEXT SEVERAL
AFTERNOON...HOWEVER CRITICAL DURATIONS OF THESE VALUES ARE NOT
EXPECTED AND LDSI VALUES SHOULD GENERALLY STAY BELOW 75.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 71 89 70 89 / 20 10 5 10
FMY 67 90 67 89 / 10 10 5 10
GIF 67 91 65 91 / 10 10 5 10
SRQ 69 85 69 85 / 20 10 5 10
BKV 67 89 65 89 / 15 10 5 10
SPG 71 85 72 83 / 20 10 5 10
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...JILLSON
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
332 PM EDT WED MAY 2 2012
.SHORT TERM...
PRIND W/VRY RECENT CONV DVLP OVER ERN IL SIMILAR IN KIND W/SHRT TERM
RUC TRENDS ALTHOUGH STILL WAITING FOR CONVN ACRS LK HURON TO DVLP
SWD INTO GROWING INSTABILITY RESERVOIR. REGARDLESS NR TERM GUIDANCE
OFFERS A SIMILAR AND COMPELLING SIGNAL LT THIS AFTN AND EVENING
W/CONVN XPCD INVOF OF OLD OUTFLW BNDRY STRETCHING FM WRN IN NEWD
INTO NW OH OR MORE LIKELY WITHIN DVLPG CONFLUENCE ZONE FM THE MI
THUMB SWWD INTO NRN IN AND ALG TAIL END OF SW TROUGH CROSSING
THROUGH ERN LK SUPERIOR ATTM. PRIOR UPDATE POPS GRIDS FM THIS MORNING
HIGHLITE ERN AREAS AND WILL CONT THAT IN PLACE LT THIS AFTN BFR
SHIFTING IT SWD THIS EVENING. OTHERWISE MORE SIG LLJ RESPONSE XPCD
TO DVLP AFT DARK ORIENTED FVRBLY INTO RETREATING OFB. GIVEN
CONCURRENCE OF HIGHRES GUIDANCE ON SHARP THETA-E RIDGE PLACEMENT
OVERNIGHT WILL CONT TO HOLD FAR SRN AREAS OUT OF ANY MENTIONABLE
POP ALG PERIPHERY OF MID LVL HGT RISES.
MORE UNCERTAIN FCST ON THU IN LIGHT OF POTENTIAL UPSTREAM MESOSCALE
DVLPMNTS OVERNIGHT YET BUY INTO THE WRF IDEA OF ANOTHER STG-SVR MCS
RIDING OUT OF IA TOMORROW MORNING AND ANOTHER OFB TO DEAL W/BY AFTN
OVR NW ZONES IN THE LEAST. OTHERWISE VRY WARM TEMPS XPCD W/LL
THERMAL RIDGE IN PLACE.
&&
.LONG TERM...FRIDAY THROUGH WEDNESDAY
BROAD UPPER RIDGING WILL DAMPENED BY SEVERAL SMALLER SCALE VORTICES
PROGRESSING THROUGH MID/UPPER FLOW TO BEGIN THE PERIOD. GUIDANCE
CONTINUES TO EXHIBIT SOME DECENT AGREEMENT IN THE STRONGEST OF THESE
SHORT WAVES...LIKELY CONVECTIVELY ENHANCED...APPROACHING THE AREA
DURING THE MORNING HOURS. VEERING LOW LEVEL JET NOSING INTO LOCAL
AREA BY MORNING AND ENHANCED LOW/MID LEVEL THETAE MOISTURE
ADVECTION/CONVERGENCE ASSOCIATED WITH THIS JET SUGGESTS A
POSSIBILITY OF REMNANTS OF OVERNIGHT MCS AFFECTING THE AREA. THIS
RAISES CONVECTIVE CONCERNS ON FRIDAY IN TERMS OF POSITIONING OF
EFFECTIVE FRONTAL BOUNDARY. SYNOPTIC FRONTAL BOUNDARY SHOULD BE
DROPPING BACK SOUTHWARD DURING THE DAY...BUT CONCERN IS THAT
EFFECTIVE OUTFLOW FROM POSSIBLE MORNING MCS MAY TAKE THE EFFECTIVE
BOUNDARY FURTHER SOUTH AND POSSIBLY FOCUS SOUTHERN AREAS FOR GREATER
AFTERNOON CONVECTIVE POTENTIAL. SEVERE POTENTIAL SOMEWHAT UNCLEAR AT
THIS TIME WITH AFOREMENTIONED CONCERNS. HOWEVER...MODERATE
INSTABILITY POSSIBLE ONCE AGAIN SOUTH OF THE EFFECTIVE BOUNDARY WITH
SOME ENHANCEMENT IN DEEP LAYER SHEAR EXPECTED IN ASSOCIATION WITH
THIS UPPER VORT MAX.
MID/UPPER LEVEL RIDGING TO BUILD BACK INTO THE AREA FRIDAY NIGHT
WITH SFC BOUNDARY BECOMING NEARLY STATIONARY ACROSS THE OHIO RIVER
VALLEY. A MORE AMPLIFIED UPPER LEVEL TROUGH WILL MOVE INTO THE
WESTERN CONUS FRIDAY NIGHT WITH RENEWED LEE CYCLOGENESIS ON
SATURDAY. THIS WILL SET THE STAGE FOR THE POSSIBILITY OF EPISODES OF
STRONGER WARM ADVECTION/OVERRUNNING TYPE FORCING FOR THE WEEKEND
WITH BEST CHANCE OF THUNDER ACROSS APPROXIMATELY SOUTHWEST HALF OF
CWA WHERE ELEVATED INSTABILITY WOULD BE SLIGHTLY MORE ENHANCED IN
THIS SETUP AND HAVE MAINTAINED LOW TO MID RANGE CHANCE POPS THROUGH
THE WEEKEND. TEMPERATURES SHOULD REMAIN FAIRLY MILD HOWEVER WITH
BRUNT OF LOW LEVEL COLD AIR REMAINING ACROSS NORTHERN GREAT LAKES
INTO SOUTHEAST CANADA.
FOR MON TO WED...12Z GFS HAS BECOME MORE INLINE WITH RECENT EC
TRENDS IN MORE OF A SPLIT FLOW TYPE PATTERN BECOMING ESTABLISHED
EARLY IN THE WEEK...WITH A MORE PROGRESSIVE AND LARGER SCALE
NORTHERN PLAINS/SOUTH CENTRAL CANADIAN UPPER TROUGH. PROGRESSION OF
THIS TROUGH SHOULD ALLOW SFC REFLECTION TO TRACK SOUTH OF THE AREA
AND ENHANCE PRECIP POTENTIAL AGAIN LATE SUNDAY NIGHT INTO
MONDAY...BEFORE CONDITIONS DRY OUT MONDAY NIGHT/TUESDAY. GIVEN TREND
IN MEDIUM RANGE MODELS TOWARD THIS GENERAL IDEA...HAVE INTRODUCED
POPS FOR MONDAY/MONDAY NIGHT WITH REMAINDER OF FORECAST KEPT DRY AS
SFC ANTICYCLONE SHIFTS EAST OUT OF THE PLAINS. TEMPERATURES ARE
EXPECTED TO COOL BACK TOWARD SEASONABLE NORMALS FOR TUE/WED.
&&
.AVIATION...
VFR CONDS XPCD THROUGH THE PD. PD OF MVFR CONDS ASSOCD/W CONVN
REMAINS ENTIRELY PSBL YET LT THIS AFTN AND EVENING YET MOST
UNCERTAIN AND HELD CLOSE W/PRIOR VCTS MENTION AT BOTH TERMINALS
GIVEN COLLABORATING RUC GUIDANCE.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...T
LONG TERM...MARSILI
AVIATION...T
AREA FORECAST DISCUSSION
NWS HASTINGS NE
345 PM CDT WED MAY 2 2012
.SHORT TERM...THROUGH 00Z FRIDAY. MORNING UPPER AIR ANALYSIS INDICATES
QUASI-ZONAL MID AND UPPER LEVEL FLOW ACROSS MUCH OF THE CENTRAL
CONUS...WITH A MID LEVEL SHORTWAVE TROUGH NOTED OVER THE
NORTHWESTERN CONUS. MID AND UPPER LEVEL JET ENERGY REMAINS
RELEGATED TO THE WEST/NORTHWESTERN CONUS...WITH TROPOSPHERIC FLOW
REMAINING FAIRLY LIGHT OVER OUR AREA. WATER VAPOR IMAGERY
INDICATES A PLUME OF MID LEVEL MOISTURE ADVANCING FROM THE PACIFIC
INTO THE SOUTHWESTERN CONUS...ONWARD INTO THE MIDDLE ROCKY
MOUNTAIN RANGE AS WELL AS PORTIONS OF THE CENTRAL AND NORTHERN
PLAINS. EARLY AFTERNOON SURFACE ANALYSIS SHOWS AN AREA OF LOW
PRESSURE OVER SOUTHWESTERN KANSAS...WITH A WARM FRONT EXTENDING
NORTHEASTWARD FROM THE LOW INTO PORTIONS OF NORTH CENTRAL KANSAS
AS WELL AS PORTIONS OF SOUTH CENTRAL AND SOUTHEAST NEBRASKA. AS OF
18Z THIS WARM FRONT WAS NOTED EXTENDING FROM NEAR KHYS...TO NEAR
KK82...TO NEAR KJYR AND KOLU. EARLY AFTERNOON TEMPERATURES ARE
GENERALLY IN THE UPPER 70S AND LOWER 80S ACROSS THE CWA...WITH DEW
POINTS RANGING FROM THE MID 40S AT KLXN...TO THE UPPER 50S THROUGH
THE TRI-CITIES...TO THE MID AND UPPER 60S ACROSS OUR SOUTHEAST
WHERE THE SURFACE WARM FRONT HAS ALREADY CLEARED. EARLY AFTERNOON
VISIBLE SATELLITE IMAGERY SHOWS MOSTLY CLEAR SKIES ACROSS OUR
NORTHWESTERN CWA...WITH THE INCREASED LOW LEVEL MOISTURE VALUES
HELPING PROMOTE INCREASED INSTABILITY AND A RESULTANT EXPANSIVE CU
FIELD.
FOR THE REST OF THIS AFTERNOON AND EARLY THIS EVENING...CONFIDENCE
IS LOW REGARDING CONVECTIVE DEVELOPMENT ACROSS OUR AREA AS FORECAST
PROXIMITY SOUNDINGS FROM THE NAM AND OPERATIONAL GFS SUGGEST
CONVECTIVE INHIBITION SHOULD HOLD FOR THE MOST PART. THAT BEING
SAID...FORECAST PROXIMITY SOUNDINGS FROM THE NAM DO SUGGEST CIN WILL
DECREASE TO ALMOST NOTHING ACROSS OUR EXTREME SOUTHEAST BY 00Z THIS
EVENING...AND WITH THE LOW LEVEL BAROCLINIC ZONE MEANDERING ACROSS
THE AREA THUS PROMOTING LOW LEVEL CONVERGENCE AND RESULTANT
FORCING...FELT IT PRUDENT TO GO WITH A SLIGHT CHANCE POP ACROSS THE
ENTIRE CWA LATE THIS AFTERNOON THROUGH THIS EVENING. THE NAM AND
OPERATIONAL GFS SUGGEST 0-1KM MLCAPE VALUES OF 2000-3500J/KG WILL BE
OBSERVED ACROSS OUR CWA LATE THIS AFTERNOON AND EVENING...WITH THE
GREATEST INSTABILITY LOCATED ACROSS OUR SOUTHEAST WITHIN THE LOW
LEVEL MOISTURE PLUME. WITH MID AND UPPER LEVEL JET ENERGY REMAINING
RELEGATED TO THE WEST/NORTHWEST OF OUR AREA...DEEP LAYER BULK SHEAR IS
NOT OVERLY IMPRESSIVE...BUT GUIDANCE DOES SUGGEST DEEP LAYER BULK
SHEAR VALUES NEAR 30KTS WILL STILL BE POSSIBLE THUS PRESENTING THE
POSSIBILITY FOR ROTATING UPDRAFTS. ALL THAT BEING SAID...SHOULD
CONVECTIVE INITIATION BE REALIZED LATE THIS AFTERNOON OR EARLY THIS
EVENING...SEVERE WEATHER WILL MOST LIKELY BE OBSERVED WITH LARGE
HAIL BEING THE PRIMARY THREAT...AND ISOLATED THUNDERSTORM WIND GUSTS
ALSO POSSIBLE ALONG OUTFLOW. FINALLY...0-1KM SRH IS NOT OVERLY
IMPRESSIVE...WITH THE NAM AND OPERATIONAL GFS SUGGESTING VALUES
SOMEWHERE AROUND 100 M^2/S^2 ACROSS OUR AREA AT 00Z...BUT WITH
LOCALLY ENHANCED LOW LEVEL HORIZONTAL VORTICITY EXISTING IN THE
VICINITY OF LOW LEVEL BAROCLINIC ZONE...ISOLATED TORNADOES ALSO
CANNOT BE RULED OUT.
ATTENTION THEN TURNS TO THE SEVERE POTENTIAL OVERNIGHT TONIGHT. THE
NAM...OPERATIONAL GFS...EC...SREF-MEAN AND HRRR ALL SUGGEST
AFTERNOON AND EVENING HIGH PLAINS CONVECTION WILL MORPH INTO A MCS
AND PUSH EAST INTO PORTIONS OF SOUTH CENTRAL NEBRASKA AND NORTH
CENTRAL KANSAS. AS THE MCS PUSHES EAST IT SHOULD BEGIN INTERACTING
WITH A 40-50KT LOW LEVEL JET WHICH SHOULD HELP SUSTAIN THE MCS IF
NOT HELP IT INTENSIFY THROUGH INCREASED LOW LEVEL MOISTURE FLUX.
GIVEN ALL THIS...A WIDESPREAD SEVERE STRAIGHT LINE WIND EVENT
SOMEWHERE ACROSS OUR CWA IS APPEARING MORE AND MORE LIKELY OVERNIGHT
TONIGHT. AS IS USUALLY THE CASE...EXACT DETAILS REGARDING PLACEMENT AND
TRACK OF THIS MCS WILL NOT LIKELY BE KNOWN UNTIL LATER THIS
EVENING...BUT GIVEN THE LATEST DATA WILL GO AHEAD AND HIGHLIGHT MOST
ALL OF THE CWA FOR SEVERE OVERNIGHT TONIGHT...WITH STRAIGHT LINE
WINDS BEING THE PRIMARY SEVERE WEATHER THREAT. ONE ADDITIONAL
NOTE...THE AFOREMENTIONED MID LEVEL MOISTURE PLUME NOTED ON WATER
VAPOR IMAGERY SHOULD PUSH OVERHEAD TONIGHT THUS HELPING TO INCREASE
PRECIPITABLE WATER VALUES. THESE INCREASING MID LEVEL MOISTURE
VALUES...ALONG WITH THE STRONG CONVECTION CURRENTLY FORECAST...WILL
HAVE THE CAPABILITY TO PROMOTE HEAVY RAINFALL AND PERHAPS LOCALIZED
FLASH FLOODING.
PRECIPITATION CHANCES FOR THURSDAY REMAIN UNCERTAIN AT THIS
POINT...ESPECIALLY WITH THE POTENTIAL FOR A SIGNIFICANT MESO-HIGH
SETTING UP OVER THE AREA DUE TO OVERNIGHT RAIN. ASSUMING THE MESO-HIGH
CAN FULLY DISSIPATE BY MID TO LATE AFTERNOON...AND ASSUMING THERE
IS ENOUGH OMEGA WITH ONE OF THE MANY MID LEVEL PERTURBATIONS WHICH
WILL BE PUSHING OVER THE AREA ALONG THE APPROACHING MID LEVEL JET
AXIS...THURSDAY AFTERNOON 0-1KM MLCAPE VALUES ON THE ORDER OF
1000-2500J/KG COULD CERTAINLY PROMOTE A SEVERE HAIL THREAT. AT
THIS TIME IT APPEARS THE BEST POTENTIAL FOR OBSERVING SEVERE
WEATHER ON THURSDAY WILL BE RELEGATED TO OUR EAST WITHIN THE
BETTER LOW LEVEL MOISTURE...AND WILL GO AHEAD AND HIGHLIGHT OUR
EAST FOR SEVERE WEATHER ON THURSDAY AS A RESULT.
.LONG TERM...STARTING WITH THE MID-TERM THURSDAY EVENING THROUGH
SATURDAY PERIOD...THE RISK OF THUNDERSTORMS...OR LACK
THEREOF...CONTINUES TO BE THE ULTIMATE DILEMMA DURING THESE 48
HOURS AND CONFIDENCE IN THE DETAILS CONTINUES TO RUN BELOW
AVERAGE. ALOFT...A BLEND OF SOLUTIONS FROM THE 12Z NAM/GFS AND 00Z
ECMWF CONTINUE TO ADVERTISE A RATHER PERSISTENT PATTERN...AS
MODESTLY STRONG...BROAD WEST-SOUTHWEST FLOW REMAINS IN
PLACE...DOWNSTREAM FROM A LARGER SCALE SHORTWAVE TROUGH THAT
CARVES OUT ACROSS THE PACIFIC NORTHWEST/NORTHERN ROCKIES. THE
PRIMARY 300MB JET AXIS WILL THUS REMAIN OFF TO THE NORTH AND WEST
OF THE REGION. HOWEVER...CONSIDERABLE CONVECTIVE INSTABILITY WILL
REMAIN FIRMLY IN PLACE IN OR NEAR THE CWA...AS A QUASI-STATIONARY
FRONT WAVERS BACK AND FORTH ACROSS THE GENERAL REGION. BEFORE
CONTINUING...WILL AGAIN STATE THAT CONFIDENCE IN THE DETAILS IS
LOW REGARDING POPS/THUNDER/SEVERE CHANCES...WITH A BIT HIGHER
CONFIDENCE IN TEMPS. HOWEVER...WAS NO LONGER WILLING TO LEAVE THE
FRIDAY THROUGH SATURDAY TIME FRAME COMPLETELY VOID OF ANY
THUNDERSTORM MENTION.
STARTING WITH THURSDAY EVENING/NIGHT...DECIDED TO BLANKET A GENERIC
20 PERCENT CHANCE OF STORMS CWA-WIDE...AS JUST CANNOT GUARANTEE A
STORM-FREE NIGHT ANYWHERE. DETERMINISTIC MODELS ARE ALL OVER THE
PLACE ON QPF PLACEMENT...WITH THE ECWMF ROLLING STORMS IN FROM THE
WEST MAINLY IN THE EVENING...WHILE THE NAM/GFS AFFECT AT LEAST
SOUTHWEST PORTIONS OF THE AREA MAINLY AFTER 06Z. LEANING ON THE 12Z
NAM...ONLY A MODEST LOW LEVEL JET IS PRESENT OVERNIGHT...BUT WITH
SUBTLE SHORTWAVES MOVING THROUGH AND HEALTHY ELEVATED MUCAPE IN
EXCESS OF 2500 J/KG HANGING OUT ACROSS MOST OF THE CWA THROUGH THE
NIGHT...JUST FEEL BETTER HAVING A TOKEN 20 PERCENT CHANCE
EVERYWHERE. HOWEVER...IT IS LIKELY THAT MOST OF THE AREA WILL IN
FACT REMAIN STORM FREE...WITH THE MOST LIKELY SCENARIO FOR POSSIBLE
CONVECTION BEING HIGH PLAINS ACTIVITY DRIFTING IN FROM THE WEST. AS
FOR SEVERE CHANCES THURSDAY NIGHT...DEEP LAYER SHEAR IS NOT ALL THAT
STRONG...20-30 KNOTS AT MOST...BUT OBVIOUSLY WITH HIGH CAPE LEVELS
HANGING AROUND CANNOT RULE OUT AT LEAST MARGINALLY SEVERE HAIL AND
WIND. AS FOR LOW TEMPS...NUDGED UP SLIGHTLY FROM PREVIOUS
FORECAST...WITH MOST OF SOUTHEAST 1/2 OF CWA HOLDING UP IN THE
LOW-MID 60S.
FOR FRIDAY...MUCH OF THE SAME...AS FORCING ALOFT REMAINS
SUBTLE...BUT INSTABILITY REMAINS HIGH WITH AFTERNOON MLCAPE VALUES
AGAIN BUILDING TO AROUND 3000 J/KG OR HIGHER PER THE NAM...ALTHOUGH
THIS MODEL MAY BE OVERDOING DEWPOINTS AND RESULTANT CAPE A BIT.
ALTHOUGH ODDS ARE REASONABLY HIGH THAT MOST OF THE AREA WILL REMAIN
STORM FREE...OPTED TO INTRODUCE A SLIGHT 20 POP ACROSS SEVERAL
COUNTIES NORTH OF I-80...AS HINTED AT BY THE 12Z GFS AND TO A LESSER
EXTENT THE 12Z NAM. AGAIN...ANYTHING THAT HAPPENS TO FIRE IN THIS
AREA BEFORE DARK COULD POTENTIALLY BE SEVERE. TEMP WISE...ASSUMING
THAT SOUTHERLY BREEZES ARE PRESENT AND CLOUDS ARE NOT
WIDESPREAD...THIS HAS THE POTENTIAL TO BE A RATHER WARM DAY.
ALTHOUGH STILL NOT AIMING QUITE AS HIGH AS THE NAM SUGGESTS...NUDGED
UP A FEW DEGREES...NOW PUTTING MOST OF THE CWA IN THE 87-90 RANGE.
FRIDAY NIGHT...INTRODUCED MORE SLIGHT THUNDERSTORM CHANCES MAINLY
NORTH OF I-80 IN CLOSEST PROXIMITY TO TRACK OF SUBTLE
SHORTWAVES...AND IN THE PRESENCE OF CONTINUED HEALTHY ELEVATED
INSTABILITY. FOR THE DAYTIME HOURS SATURDAY...JUST CONTINUED WITH
MORE OF THE SAME...KEEPING THE SAME AREAS NORTH OF INTERSTATE 80 IN
A SLIGHT CHANCE OF STORMS...BUT WITH BETTER FOCUS LIKELY TARGETING
AREAS JUST TO THE NORTH. BY THIS TIME...THE PRIMARY MID LEVEL TROUGH
TO THE WEST WILL BE CENTERED ROUGHLY ALONG A MT-UT AXIS...BUT STILL
WELL TO THE WEST. TEMP WISE SATURDAY...KEPT SUMMER-LIKE READINGS
GOING AND EVEN NUDGED UP A FEW DEGREES FROM PREVIOUS PER MODEL
CONSENSUS...WITH MID-UPPER 80S MOST AREAS...AND SOME LOW 90S MOST
FAVORED IN KS ZONES.
FOCUSING NOW ON THE LONGER TERM PERIODS SATURDAY NIGHT THROUGH
NEXT WEDNESDAY: IN SHORT...EACH AND EVERY PERIOD FEATURES AT LEAST
20-30 PERCENT RAIN CHANCES FOR NOW...ALTHOUGH WILL STATE THE OBVIOUS
THAT SOME OF THESE PERIODS WILL LIKELY END UP BEING DRY...WITH
PLENTY OF TWEAKING LIKELY OVER THE NEXT SEVERAL DAYS. LOOKING AT THE
BIG PICTURE AND LEANING TOWARD A BLEND OF THE 12Z ECMWF/GFS...THERE
IS ACTUALLY REASONABLY HIGH AGREEMENT THAT ON SATURDAY NIGHT AND
SUNDAY NIGHT A FAIRLY WELL DEFINED SURFACE COLD FRONT WILL CROSS THE
AREA...DRIVEN SOUTHWARD IN RESPONSE TO THE AFOREMENTIONED MID LEVEL
SHORTWAVE TROUGH RIDING UP ACROSS THE NORTHERN PLAINS INTO SOUTH
CENTRAL CANADA. AS A RESULT OF THIS FRONTAL PASSAGE...THE HIGHEST
POPS IN THE EXTENDED PERIOD...40S-50S PERCENTS ACROSS MAINLY NEB
ZONES FOR NOW...ARE FOCUSED ON SATURDAY NIGHT. ALTHOUGH DEEP LAYER
WIND SHEAR DOES NOT LOOK OVERLY IMPRESSIVE WITH THIS FRONTAL
PASSAGE...THE GFS HAS MUCAPE VALUES OF AT LEAST 2000-3000 J/KG IN
PLACE DURING THIS TIME FRAME...SO CERTAINLY A SLIGHT RISK OF SEVERE
NOT OUT OF THE QUESTION. IN THE WAKE OF THIS BOUNDARY...TEMPS SUNDAY
ARE CURRENTLY FORECAST ABOUT 10 DEGREES COOLER THAN
SATURDAY...RANGING FROM LOW 70S NORTHWEST TO LOW 80S SOUTHEAST.
BEYOND SUNDAY...THE CURRENTLY ADVERTISED POPS WOULD SEEM TO COME
MORE AND MORE UNDER QUESTION...BUT WILL STICK WITH THEM PER NOW
ACCORDING TO THE ALLBLEND CONSENSUS INITIALIZATION. THE BASIC STORY
INVOLVES A GRADUAL CARVING OUT OF A MID LEVEL TROUGH ACROSS THE
NORTH CENTRAL CONUS...RESULTING IN A NOTICEABLY COOLER TEMP REGIME
THAN THE CURRENT PATTERN. NUDGED DOWN HIGHS SLIGHTLY FOR MONDAY WITH
UPPER 60S-LOW 70S...WHILE TUESDAY CONTINUES TO LOOK LIKE THE COOLEST
DAY OF THE PERIOD WITH HIGHS ONLY MID-UPPER 60S ALL AREAS AND MAYBE
A REBOUND TO NEAR 70 WEDNESDAY. EVEN IF RAIN WERE TO MATERIALIZE
DURING THE MONDAY NIGHT-WEDNESDAY TIME FRAME...HAVE DROPPED THUNDER
MENTION IN THE FORECAST IN FAVOR OF PLAIN SHOWERS...AS MUCAPE PROGS
FROM BOTH THE ECMWF/GFS ADVERTISE VERY LIMITED IF ANY CONVECTIVE
INSTABILITY. IN CLOSING...WANT TO REITERATE THAT ALTHOUGH POPS IN
THE SAT NIGHT-SUNDAY TIME FRAME LOOK QUITE WARRANTED...WOULD EXPECT
TO SEE AN EVENTUAL TRIMMING OF SOME OF THE RAIN CHANCES DURING THE
SUNDAY NIGHT-WEDNESDAY TIME FRAME.
&&
.PREV DISCUSSION... /ISSUED 1228 PM CDT WED MAY 2 2012/
AVIATION...18Z KGRI TAF. PREVAILING VFR CONDITIONS EXPECTED
THROUGH THE NEXT 24 HOURS...WITH PERIODIC MVFR CEILINGS POSSIBLE
03Z-07Z AS CONVECTIVE ACTIVITY WITH MODERATE RAIN PUSHES THROUGH
THE AREA. SURFACE WINDS WILL REMAIN FROM THE SOUTHEAST THROUGH
MUCH OF THE TAF PERIOD...BUT MAY TRANSITION TO MORE OF A
NORTHEASTERLY DIRECTION 03Z-11Z AS A SURFACE BOUNDARY MEANDERS
ACROSS THE AREA. MINIMAL VISIBILITY RESTRICTIONS WILL BE POSSIBLE
03Z-07Z IN MODERATE RAIN...BUT VISIBILITY RESTRICTIONS ARE NOT
OTHERWISE EXPECTED.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM/AVIATION...BRYANT
LONG TERM...PFANNKUCH
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
243 PM CDT WED MAY 2 2012
.SHORT TERM...TONIGHT AND THURSDAY.
THE LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW
PRESSURE SITUATED OVER WESTERN KANSAS EARLY THIS AFTERNOON...AND A
COLD FRONT EXTENDING NORTHEAST INTO THE NORTHERN MISSISSIPPI
VALLEY. AN OUTFLOW BOUNDARY FROM THIS MORNINGS CONVECTION HAS
REACHED INTO NORTHERN MISSOURI AND CENTRAL ILLINOIS...THOUGH
CONVECTION HAS YET TO RE-DEVELOP. CLOUD COVER HAS BEEN BUILDING
ACROSS IOWA THIS AFTERNOON WHERE THETAE ADVECTION IS ONGOING...BUT
NO SIGN OF PRECIP HERE EITHER. MEANWHILE...MIXING INTO DRY AIR
ALOFT HAS DISSIPATED THIS MORNINGS CLOUD COVER INTO SCATTERED CU
OVER MUCH OF THE FORECAST AREA. AS A LOW LEVEL JET DEVELOPS AHEAD
THE LOW PRESSURE AND CONVECTION DEVELOPS UPSTREAM...SEVERE WEATHER
CHANCES AND PRECIP AMOUNTS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...PLENTY OF UNCERTAINTY WITH THE DETAILS CONCERNING
POTENTIAL CONVECTION. SHORTWAVE TROUGH OVER MONTANA WILL LIFT NE
OVER NORTH DAKOTA AND INTO SOUTH-CENTRAL CANADA. SW FLOW ALOFT WILL
KEEP LOW PRESSURE OVER THE CENTRAL PLAINS WHILE THE COLD FRONT BECOMES
MORE PERPENDICULAR TO THE LOW LEVEL FLOW OVER IOWA AND INTO
WISCONSIN. AHEAD OF THE SURFACE LOW...A SOUTH TO SOUTHWEST LLJ WILL
DEVELOP LATE THIS AFTERNOON INTO THIS EVENING POINTING INTO IOWA AND
NORTHERN ILLINOIS. GOOD MASS CONVERGENCE ON THE NOSE OF THIS LLJ IN
AN AREA OF MU CAPE 1500-2000 J/KG AND MID-LEVEL LAPSE RATES OF 7 TO
7.5 C/KM SHOULD BE SUFFICIENT TO TRIGGER ELEVATED CONVECTION.
FORWARD PROPAGATING CORFIDI VECTORS WOULD TRACK SUBSEQUENT MCS
ENE...THOUGH AM EXPECTING THE STRONGEST THUNDERSTORMS TO FOLLOW THE
GREATEST INSTABILITY OVER THE SOUTHERN 1/3RD OF THE BADGER STATE AND
NORTHERN ILLINOIS. THE 12Z GFS DOES TRY TO RAM THE LLJ INTO EAST-CENTRAL
WISCONSIN ALONG WITH AMPLE INSTABILITY...BUT THINK THIS IS TOO
AMBITIOUS GIVEN THE WSW FLOW ALOFT AND WITHOUT MUCH MID-LEVEL HEIGHT
RISES. THE FLOW DOES TURN A BIT MORE SW OVERNIGHT AS THE RIGHT REAR
QUAD OF A JET STREAK SHIFTS INTO NORTHERN WISCONSIN...SO AM
EXPECTING TO SEE A MORE NORTHWARD PUSH OF THE NOCTURNAL CONVECTION
ACROSS THE FORECAST AREA AFTER MIDNIGHT. WITH THE ELEVATED
INSTABILITY AXIS REMAINING TO OUR SOUTH...HAVE A HARD TIME GETTING
EXCITED ABOUT SEVERE CHANCES...THOUGH ALWAYS TOUGH TO RULE OUT A
MARGINAL SEVERE STORM ADVECTING INTO THE SOUTHERN FORECAST AREA.
WILL KEEP A MENTION OF SEVERE POSSIBILITIES FOR CENTRAL AND
EAST-CENTRAL WISCONSIN...MAINLY FOR LARGE HAIL...AND STRONG WINDS TO
A LESSER EXTENT. CENTRAL AND EAST-CENTRAL WISCONSIN WILL LIKELY SEE
SUBSTANTIAL RAINFALL...WITH SOME GUIDANCE POINTING TOWARDS WELL OVER
AN INCH OF RAIN. WILL TRY TO CAP IT AROUND THERE...SINCE THE
GREATER INSTABILITY IS SOUTH OF THE FORECAST AREA.
THURSDAY...MORNING CONVECTION MAY VERY WELL BE ONGOING AT THE START
OF THE PERIOD...AS THE RIGHT REAR QUAD OF THE JET STREAK WILL BE
OVERHEAD WHILE 850MB CONVERGENCE WILL BE DRAPED OVER CENTRAL
WISCONSIN. THINK THE MORNING MAY TURN OUT TO BE WETTER THAN MODELS
INDICATE AND WILL KEEP THE NEAR CATEGORICAL POPS IN THE FORECAST.
INSTABILITY WILL BE THE QUESTION MARK FOR THE AFTERNOON...AS THE
WARM FRONT WILL REMAIN STALLED ACROSS THE AREA. THE RIGHT REAR QUAD
OF THE JET STREAK WILL PULL OUT BY THE AFTERNOON...BUT WILL DAYTIME
HEATING LEAD TO CLEARING...DESPITE AMPLE MOISTURE THROUGH THE
COLUMN? THINK ANY BREAKS WILL JUST LEAD TO CU BUILD-UP...RESULTING
IN A MOSTLY CLOUDY DAY REGARDLESS. STILL SOME CAPE TO BE HAD...SO
CANNOT RULE OUT SCATTERED COVERAGE OF SHOWERS AND STORMS THROUGH THE
AFTERNOON. WILL MAKE ONLY COSMETIC CHANGES TO POPS. HIGHS IN THE
LOW TO MID 70S.
.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY. PCPN CHANCES
WILL BE THE PRIMARY FORECAST ISSUE DURING THIS PERIOD. BUSY WSW
FLOW TO CONTINUE INTO FRIDAY BEFORE MEDIUM RANGE MODELS IN
AGREEMENT WITH BRIEFLY BUILDING AN UPPER RIDGE OVER THE WESTERN
GREAT LAKES REGION SATURDAY INTO SUNDAY. THIS UPPER RIDGE BEGINS
TO FLATTEN LATE IN THE WEEKEND WITH A RETURN TO A SOUTH TO
SOUTHWEST FLOW AHEAD OF A SHORT WAVE TROUGH. MEANWHILE THE
SURFACE BOUNDARY WITH BEST INSTABILITY DROPS WELL SOUTH OF THE
FORECAST AREA LATER FRIDAY INTO FRIDAY NIGHT WITH AN EAST TO
NORTHEAST FLOW AROUND A SURFACE HIGH OVER SOUTHERN CANADA.
WOULD NORMALLY BE AGGRESSIVE WITH ENDING POPS IN THIS
SCENARIO...BUT MDM RANGE MODELS ARE CONSISTENTLY LINGERING A WEAK
H8 BOUNDARY OVER WISCONSIN FOR A POSSIBLE FOCUS OF CONVECTION FOR
AT LEAST A CHANCE OF SHOWERS. THIS H8 BOUNDARY WITH WARMER H8 TEMPS WERE
PRODUCING TOTAL TOTAL VALUES IN THE LOWER 50S...ESPECIALLY TOWARD
WESTERN WISCONSIN. IN ADDITION...BEST UPPER JET DYNAMICS LINGER
ACROSS THE NORTHERN GREAT LAKES REGION TO PROVIDE AREAS OF LIFT.
FOR THE NEW WORK WEEK...A PROGGED DEEPENING UPPER TROUGH WITH
FRONTAL SYSTEM WILL PROVIDE MORE EVEN PCPN CHANCES OF PCPN
THROUGH AT LEAST WEDNESDAY BEFORE A HIGH PRESSURE RIDGE TRIES TO
BUILD IN FROM THE NORTHERN PLAINS AND CANADA. BY MID WEEK NEXT
WEEK PCPN CHANCES MAY BE PRIMARILY DIURNAL VARIETY AS THE UPPER
TROUGH SLOWLY DRIFTS OVER.
&&
.AVIATION...BKN MVFR CIGS OVER NORTHERN WISCONSIN SHOULD STICK
AROUND THROUGH MID-AFTERNOON UNTIL DRIER AIR MIXES AND HELPS ERODE
THE CLOUD COVER. OTHERWISE FOR TONIGHT CIGS AND VSBYS WILL LOWER
FROM VFR TO IFR FROM SOUTHWEST TO NORTHEAST AS AN AREA OF SHOWERS
AND THUNDERSTORMS APPROACHES FROM THE CENTRAL PLAINS. PLENTY OF
UNCERTAINTY HOW THIS AREA OF RAIN WILL EVOLVE...INCLUDING TIMING AND
COVERAGE. THE LATEST THINKING IS THAT CENTRAL AND EAST-CENTRAL
WISCONSIN WILL SEE THUNDERSTORMS ARRIVE LATE THIS EVENING OR EARLY
OVERNIGHT...AND THAT ARRIVAL TIME WILL BE SLIGHTLY POSTPONED FARTHER
NORTH. WIDESPREAD IFR CIGS TO HANG AROUND THROUGH MID-MORNING WITH
A WARM FRONT DRAPED ACROSS THE REGION.
&&
.HYDROLOGY...RAINFALL AMOUNTS OVER CENTRAL AND EAST CENTRAL
WISCOMSIN FROM LAST NIGHS CONVECTION RANGED FROM 0.40 TO 0.80
INCHES. MORE RAIN IS ANTICIPATED TONIGHT INTO THRUSDAY MORNING AS
A WARM FRONT LIFTS INTO SOUTHERN AND CENTRAL WISCONSIN. PWATS
APPROACH 1.50 BY THURSDAY MORNING. AT THIS TIME BETWEEN 1 TO 1.50
INCHES AREAS RAIN IS EXPECTED FROM TONIGHT THROUGH NOON THURSDAY.
DO NOT EXPECT FLOODING AT THESE NUMBERS...BUT IF STORMS BECOME
MORE WIDESPREAD AND CAN TRAIN ALONG THE WARM FRONT...LOCALLY
HIGHER AMOUNTS POSSIBLE. MAIN STEM RIVERS ARE FAIRLY LOW SO
RUNOFF IS NOT EXPECTED TO IMPACT RIVERS...HOWEVER SMALL STREAMS
MAY BEGIN TO BECOME SWOLLEN IF THE HIGHER AMOUNTS VERIFY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/TDH