Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 04/20/12
AREA FORECAST DISCUSSION
NWS LITTLE ROCK AR
914 PM CDT THU APR 19 2012
.UPDATE...
JUST SOME MINOR TWEAKS TO THE FORECAST FOR THE OVERNIGHT PERIOD.
SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG A FRONT IN CENTRAL
OKLAHOMA THIS EVENING...AND EXTEND NORTHEAST TO NEAR TULSA. RAPID
REFRESH RUC GUIDANCE SUGGESTS CONVECTION WILL CONTINUE ALONG THE
FRONT AND WILL EXPAND SOMEWHAT AS IT MOVES TOWARDS ARKANSAS. THIS
WOULD PUT SOME SHOWERS AND ISOLATED TSTMS IN THE NORTHWEST
COUNTIES BY AROUND DAYBREAK. HOWEVER...RUC GUIDANCE SUGGESTS MORE
DOMINANT/WIDESPREAD AREA OF PRECIP WILL APPROACH SOUTHWEST
ARKANSAS A FEW HOURS AFTER DAWN THANKS IN PART TO STRONGER SFC LOW
ALONG THE FRONT IN NE TEXAS. AS SUCH...LOWERED POPS JUST A TAD IN
THE NORTHWEST AFTER 12Z. STILL HAVE HIGH CHANCE VALUES UP
THERE...BUT LEFT THE LIKELY VALUES CONFINED TO AREAS SOUTH OF THE
I-40 CORRIDOR AND WEST OF CLARKSVILLE.
PER THE RUC AND LATEST 12KM NAM GUIDANCE...PRECIP WILL LIKELY
SLACKEN A BIT BETWEEN 12Z-18Z BUT WILL THEN PICK UP IN COVERAGE
AND INTENSITY DURING THE AFTERNOON HOURS. NORTHERN AREAS MAY NOT
SEE MUCH OUTSIDE OF SOME SHORT SPITS OF RAIN OR DRIZZLE FROM MID
TO LATE MORNING IF THE NAM VERIFIES. DECIDED NOT TO TRY AND TIME
SUCH DRY PERIODS THOUGH AND LEFT THE LATE MORNING AND
AFTERNOON/EVENING POP FORECASTS FOR TOMORROW ALONE.
OTHERWISE...FORECAST APPEARS TO BE ON TRACK AND NO OTHER CHANGES
WERE MADE.
&&
.PREV DISCUSSION... /ISSUED 642 PM CDT THU APR 19 2012/
AVIATION...
A STORM SYSTEM IN THE CENTRAL PLAINS WILL CONTINUE TO ADVANCE EAST
THOUGH THE PERIOD. THE ASSOCIATED COLD FRONT WILL MOVE THROUGH
THE STATE WITH WIDESPREAD PRECIPITATION EXPECTED ALONG AND BEHIND
THE BOUNDARY. WINDS WILL ALSO BE SHIFTING FROM THE SOUTH TO MORE
OF A NORTHERLY DIRECTION BEHIND THE FRONT BUT WILL REMAIN AROUND
10 KNOTS. WIDESPREAD VFR CONDITIONS WILL PREVAIL THROUGH THE
PERIOD WITH OCCASIONAL MVFR CONDITIONS IN ANY THUNDERSTORM
ACTIVITY.
PREV DISCUSSION... /ISSUED 240 PM CDT THU APR 19 2012/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
HIGH PRES RDG WAS SITUATED JUST E OF THE FA THIS AFTN...WITH A
GENERAL SELY WIND FLOW NOTED. WITH FAIRLY DRY AIR STILL IN PLACE
ACRS THE REGION...ABUNDANT SUNSHINE ALLOWED MID AFTN TEMPS TO CLIMB
INTO THE MID AND UPR 70S. MEANWHILE...LOW PRES CONTD TO DVLP OVR THE
SRN PLAINS AND WL EVENTUALLY AFFECT THE MID SOUTH OVR THE NEXT 24 TO
36 HRS.
MOISTURE LVLS WL START TO INCRS SIGNIFICANTLY FM THE W TNGT AND FRI
AS THE AFOREMENTIONED STORM SYS MOVES CLOSER TO AR. ASSOCD CDFNT
RMNS PROGGED TO ENTER NWRN AR FRI MRNG AND MOVE THRU THE REST OF THE
STATE BY FRI EVENING. A BAND OF MAINLY POST-FNTL SHRA/EMBEDDED TSRA
WL ACCOMPANY THE BNDRY...WITH A GENERAL 1/2 TO ONE INCH OF QPF
EXPECTED. PARTS OF SERN AR COULD SEE LOCALLY HIGHER AMTS.
CANNOT RULE OUT SOME LINGERING RAIN CHCS ACRS PARTS OF FAR SERN AR
EARLY ON SAT. OTHERWISE...NWLY WINDS WL USHER COOLER AND DRIER AIR
INTO THE REGION. TEMPS WL TREND DOWN TO BLW NORMAL LVLS IN THE
COMING DAYS.
LONG TERM...MONDAY THROUGH THURSDAY
RIDGING OVER THE HIGH PLAINS WILL PROVIDE NW UPR FLOW TO THE NATURAL
STATE FOR THE MAJORITY OF THE LONG TERM. THE NW FLOW WILL GRADUALLY
SHIFT EAST BY THURSDAY WHILE AT THE SAME TIME SFC HIGH PRESSURE
DRIFTS EAST OF THE STATE. THIS WILL ALLOW AN OVERALL WARMING TREND
THROUGH THE PD AS SRLY LOW LVL FLOW DEVELOPS.
OVERALL...VERY FEW CHANGES WERE MADE TO THE FCST AS PREDOMINATELY
DRY CONDS ARE EXPECTED. HOWEVER...GIVEN THAT NW UPR FLOW CAN AT
TIMES SURPRISE US WITH UNEXPECTED CLOUDS OR PRECIP DUE TO MODEL
UNDERFORECAST SHRTWVS...HAVE INCREASED CLOUD COVER FOR MUCH OF THE
MIDDLE PART OF THE WEEK GIVEN A FEW SHRTWVS DIVING INTO THE UPR
TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 78 55 68 44 / 0 30 80 50
CAMDEN AR 80 55 76 50 / 0 20 80 60
HARRISON AR 79 54 59 39 / 0 50 70 20
HOT SPRINGS AR 80 56 69 48 / 0 30 80 40
LITTLE ROCK AR 81 57 71 48 / 0 20 80 50
MONTICELLO AR 80 56 78 51 / 0 10 60 60
MOUNT IDA AR 79 55 66 47 / 0 40 80 30
MOUNTAIN HOME AR 81 54 62 40 / 0 40 80 20
NEWPORT AR 78 55 70 46 / 0 20 70 50
PINE BLUFF AR 79 55 74 50 / 0 10 70 60
RUSSELLVILLE AR 81 56 66 44 / 0 40 80 30
SEARCY AR 81 54 70 47 / 0 20 80 50
STUTTGART AR 78 56 72 49 / 0 10 80 60
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
64
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1018 AM MDT WED APR 18 2012
.UPDATE...CURRENT FORECAST TRENDS STILL LOOKING ON TRACK WITH NO
PLANS FOR CHANGES AT THIS TIME. FAR NORTHEAST CORNER STILL IN A
GENERAL AREA FOR TSTMS PER SPC. RUC SHOWS A BULLSEYE OF AROUND 400
CAPE AT THE SURFACE ALONG WITH SOME CIN...REST OF THE MODELS LESS
GENEROUS. THERE LOOKS TO BE SOME SURFACE CONVERGENCE WHICH COULD
HELP EXTINGUISH ANY CIN...BUT LOOKS MINIMAL. NOT INCLUDE ANY
THUNDER BUT WILL CONTINUE TO MONITOR.
&&
.AVIATION...CURRENT TAF TRENDS LOOKING ON TRACK. SOUTHEAST WINDS
TO SHIFT TO THE SOUTHWEST THEN TOWARD THE NORTHWEST DURING THE
AFTERNOON. POTENTIAL FOR WINDS TO BECOME A BIT NORTH OR NORTHEAST
TONIGHT...THOUGH STILL SOME UNCERTAINTY. SOME POTENTIAL FOR
CEILINGS AROUND 7000 FEET AGL NORTH AND EAST OF THE AREA AIRPORTS
THIS AFTERNOON ALONG WITH SOME VIRGA AND PERHAPS GUSTY WINDS. THIS
LOW THREAT SHOULD NOT AFFECT AREA AIRPORTS. SOME SHOWERS POSSIBLE
THIS EVENING...APPEARS CEILINGS SHOULD BE ABOVE ILS CONCERNS.
&&
.PREV DISCUSSION... /ISSUED 322 AM MDT WED APR 18 2012/
SHORT TERM...TODAY IS LOOKING A LOT LIKE YESTERDAY WITH ANOTHER
SHORT WAVE BRINGING MID AND HIGH LEVEL MOISTURE IN FROM THE WEST
DURING THE DAY. TWO MINOR DIFFERENCES...THERE IS A LITTLE WARM
ADVECTION ALOFT...AND THERE IS A BIT MORE MOISTURE ALOFT AS WELL.
IT LOOKS LIKE CLOUD COVER WILL HOLD TEMPERATURES RIGHT AT THE
CONVECTIVE TEMPERATURE...CREATING A VERY MARGINAL CONVECTIVE
ENVIRONMENT. I SUSPECT THAT CONVECTION TODAY WILL BE LIMITED TO
FAIRLY WEAK ACTIVITY IN THE ELEVATED MOIST LAYER...THE INCREASED
MOISTURE MAY RESULT IN MORE CLOUDS/VIRGA BUT NOT NECESSARILY ANY
MORE RAIN. I TRIMMED POPS BACK A LITTLE ON THE PLAINS WHERE THE
CHANCES ARE PRETTY LOW UNTIL EVENING WHEN BETTER LIFT ARRIVES.
MOIST LAYER MAY LOWER ENOUGH TO ALLOW SOME PRECIP TO REACH THE
SURFACE OVERNIGHT...MORE LIKELY IN THE NORTHERN PART OF THE AREA.
HIGHER POPS OF COURSE IN THE MOUNTAINS WHERE VIRGA TURNS INTO RAIN
AND SNOW SHOWERS AS YOU GO UPHILL...BUT NOT EXPECTING MUCH IN THE
WAY OF AMOUNTS...AND AGAIN BETTER NEARER THE NORTHERN BORDER.
TRIMMED TEMPERATURES BACK A FEW DEGREES IN LINE WITH THE LATEST
GUIDANCE...AND THE INCOMING CLOUD COVER.
LONG TERM...A MODERATE WEST TO NORTHWESTERLY FLOW ALOFT WILL BE
OVER CO THURSDAY AS A WEAK UPPER LEVEL TROUGH MOVES ACROSS THE
STATE. OVERALL THE MID AND UPPER LEVEL QG ASCENT IS WEAK BUT IT
IS PROGGED TO MOVE OVER THE CWFA AROUND 18Z. IN THE MOUNTAINS
DECENT MOISTURE...WITH A FAVORABLE OROGRAPHIC COMPONENT WILL BE IN
PLACE WITH NORTHWEST WINDS IN THE 25-30 KT RANGE AROUND 650 MB.
MID LEVEL INSTBY HOWEVER WILL BE FAIRLY WEAK. WL GO WITH LIGHT
SNOW AMOUNTS IN THE MOUNTAINS...GREATEST POTENTIAL FOR
ACCUMULATIONS WILL BE ALONG THE HIGHER WEST FACING SLOPES. ACROSS
THE NORTHEAST PLAINS...WL GO WITH PRIMARILY RAIN SHOWERS WITH THE
MENTION OF A FEW TSTMS. CAPES NOT VERY IMPRESSIVE WITH VALUES OF
150-250 J/KG IN THE AFTN. IN ADDITION TO THE AFTN HEATING...THE QG
ASCENT ASSOCIATED WITH THE TROUGH WILL BE PASSING OVER THE
NORTHEAST PLAINS IN THE AFTN. WL KEEP SOME SHOWERS GOING ACROSS
THE CWFA THURSDAY NIGHT...BUT OVERALL CONDITIONS WILL
IMPROVE...ESPECIALLY AFTER 06Z FRIDAY. FOR THE REMAINDER OF THE
PERIOD...IT WILL GENERALLY BE DRY AND WARMER AS A RIDGE OF HIGH
PRESSURE ESTABLISHES ITSELF OVER THE WESTERN U.S. THE RIDGE MAY
FLATTEN SOMEWHAT BY THE MIDDLE OF NEXT WEEK AS SOME SYSTEMS MOVE
ACROSS THE NORTHERN ROCKIES...BUT NOTHING SIGNIFICANT ENUF AT THIS
TIME TO WARRANT ADDITION OF ANY POPS TO THE GRIDS FOR NEXT WEEK.
AVIATION...VFR CONDITIONS EXPECTED THROUGH TONIGHT. THE WIND
SHOULD SHIFT TO A NORTH TO NORTHWEST DIRECTION IN THE MID TO LATE
AFTERNOON. SOME UNCERTAINTY ABOUT THE WIND DIRECTION
OVERNIGHT...BUT THERE WILL PROBABLY NOT BE MUCH CHANGE IN THE
EARLY EVENING AND SPEEDS WILL BE 10 KNOTS OR LESS.
HYDROLOGY...PCPN WILL BE FAIRLY LIGHT AS THE SYSTEM MOVES OVER
THE BURN AREAS ON THURSDAY SO DO NOT ANTICIPATE ANY FLOODING
ISSUES AT THIS TIME.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...D-L
LONG TERM....COOPER
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1104 AM EDT WED APR 18 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL BUILD TO THE EAST OVER THE
AREA INTO THURSDAY. WEAK HIGH PRESSURE BUILDS OFFSHORE ON FRIDAY.
AN APPROACHING FRONTAL SYSTEM AND WAVES OF LOW PRESSURE FORMING
ALONG THE FRONT WILL IMPACT THE REGION OVER THE WEEKEND AND INTO
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID TO HIGH CLOUDS OVER WESTERN PORTIONS OF THE CWA ARE STRUGGLING
TO PUSH INTO EASTERN PORTIONS OF THE CWA IN RESPONSE TO A MINI
700-500 HPA RIDGE OVER THE EAST. WITH THIS FEATURE FORECAST TO
PUSH TO THE EAST...WOULD EXPECT THE CLOUDS TO OVERSPREAD EASTERN
PARTS OF THE AREA THIS AFTERNOON...WITH MOST AREAS MOSTLY
CLOUDY/PARTLY SUNNY.
KEPT THE FORECAST DRY FOR TODAY AS 12Z SOUNDINGS AT KALY AND KOKX
SHOW VERY DRY LOW LEVELS...SO WOULD ONLY EXPECT SOME VIRGA OVER
WESTERN PORTIONS OF THE CWA THIS AFTERNOON.
FOR HIGHS...WITH CLOUD COVER A BIT MORE EXPANSIVE THAN ORIGINALLY
EXPECTED...HAVE TWEAKED THEM DOWN A DEGREE OR TWO FOR
NOW...CONSISTENT WITH A BLEND OF MIXING DOWN FROM 900 HPA...NAM
2-METER TEMPERATURES AND A BLEND OF MET AND MAV GUIDANCE.
DEPENDING ON EXACTLY HOW THE CLOUD COVER PLAYS OUT...MIGHT HAVE TO
LOWER A BIT MORE WITH THE NEXT UPDATE.
MADE MINOR CHANGES IN SEABREEZE TIMING FOR THIS
AFTERNOON...STARTING IT 1-2 HOURS EARLY BASED ON BLEND OF
CONSISTENT HRRR AND NAM 10M WINDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
THE QUIET CONDITIONS CONTINUE TONIGHT WITH THE HIGH PRESSURE MOVING
THROUGH THE NORTHEAST AND SETTLING OFFSHORE TO THE EAST THURSDAY. AS
THE HIGH MOVES...WINDS WILL SHIFT TO A MORE PERSISTENT SOUTHERLY
FLOW AND INCREASE...THOUGH STILL REMAINING LESS THAN 10 KTS.
THE 00Z GFS BRINGS IN POPS FOR THE WESTERN CWA TONIGHT WITH LOW
PRESSURE AT 700MB PUSHING IN FROM THE SOUTH BETWEEN 03Z AND 09Z. THE
12Z ECMWF AND 00Z NAM HINT AT THIS AS WELL...BUT KEEP ALL PRECIP TO
THE SOUTH WITH THE BETTER UPPER LEVEL FORCING. DID NOT INCLUDE ANY
PRECIP FOR TONIGHT...SIDING MORE WITH THE ECMWF AND NAM.
HOWEVER...THE MOISTURE AT THE 700MB WILL LEAD TO DEVELOPMENT OF
MID TO HIGH LEVEL CLOUDS OVER THE SOUTHERN PARTS OF THE
CWA...WHILE SUBSIDENCE ALOFT WILL HELP TO SCATTER SKIES IN THE
NORTHERN PORTION OF THE CWA. THIS MOISTURE PUSHES THROUGH BY
THURSDAY MORNING...AND WITH THE UPPER LEVEL SUBSIDENCE
CONTINUING...SHOULD SEE PARTLY CLOUDY SKIES THURSDAY.
925MB AND 850MB FLOW BECOMES MORE WSW TONIGHT AND THURSDAY...ONCE
AGAIN ALLOWING FOR WARMER TEMPS TO BE INJECTED IN. TEMPS WILL BE A
FEW DEGREES ABOVE NORMAL...USING A MOS/NAM BLEND ONCE AGAIN.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
FORECAST CHALLENGE CONTINUES TO BE WITH A DEVELOPING STORM SYSTEM
OVER THE EASTERN THIRD OF THE COUNTRY THIS WEEKEND. BOTH THE 00Z GFS
AND ECMWF HAVE TRENDED SLOWER...DEEPER...AND WETTER WITH THE SYSTEM
WHICH WILL IMPACT THE AREA SAT-MON. THERE IS THE POTENTIAL FOR
SEVERAL INCHES OF RAINFALL. WHILE MUCH NEEDED...ANY LARGE AMOUNT OF
RAINFALL OVER A SHORT PERIOD TIME DOES RAISE FLOODING CONCERNS.
THERE STILL IS UNCERTAINTY WITH THE LOCATION AND MAGNITUDE OF THE
CUTOFF LOW THAT FORMS OVER THE MID ATLANTIC STATES...AS WELL AS WITH
THE RESULTANT SURFACE LOW AND COASTAL FRONT. THESE DETAILS WILL BE
BETTER REFINED AS WE GET CLOSER TO THE EVENT.
INITIALLY...A NEARLY ZONAL FLOW STARTS OUT THU NIGHT...THEN SHORT
WAVE ENERGY OVER THE PLAINS SPLITS ACROSS THE LOWER MS VALLEY AND
OHIO VALLEY STATES. SUBSEQUENT SHORT WAVE ENERGY DIGS INTO THE
NORTHERN BRANCH TROUGH. THIS AMPLIFICATION EVENTUALLY LEADS TO PHASING
WITH THE SOUTHERN BRANCH. NEEDLESS TO SAY...SOME COMPLEX
INTERACTIONS GOING ON HERE...BUT TO SEE THE 00Z GUIDANCE POINTING
IN THIS DIRECTION DOES MAKE THE SOLUTION MORE CREDIBLE. THERE ALSO
APPEARS TO BE A FEED OF BOTH GULF OF MEXICO AND TROPICAL ATLANTIC
MOISTURE INTO THE SYSTEM.
THE WEEK WILL END ON A DRY NOTE WITH HIGH PRESSURE BUILDING
OFFSHORE. A PAC FRONTAL SYSTEM APPROACHES FRI NIGHT INTO
SAT...BECOMING NEARLY STATIONARY ALONG THE EAST COAST OVER THE
WEEKEND. THE 12Z MODEL RUN WAS MORE PROGRESSIVE IN ALLOWING THE
FRONT TO PUSH OFFSHORE SUN MORNING. THIS IS CURRENTLY REFLECTED IN
THE GRIDS WITH WINDS BECOMING NE...HOWEVER THE 00Z ECMWF SUPPORTS
THE GFS WITH A SLOWER PROGRESSION. THUS...THE FLOW MAY REMAIN
SOUTHERLY INTO EARLY NEXT WEEK UNTIL DEEPENING LOW PRESSURE PASSES
TO THE NORTH AND WEST. BEFORE MAKING LARGE WHOLESALE CHANGES...WOULD
LIKE TO SEE SOME CONTINUITY MAINTAINED WITH THE 12Z CYCLE. THE BEST
CHANCE FOR RAIN AT THIS TIME APPEARS TO BE FROM SAT NIGHT INTO MON.
AS FOR TEMPS...REMAINING SEVERAL DEGREES ABOVE NORMAL FRI AND SAT.
RAIN COOLED AIR WILL RESULT IN DAYTIME HIGHS SUN-TUE NEAR
NORMAL...WITH OVERNIGHT LOWS A FEW DEGREES ABOVE NORMAL DUE TO THE
CLOUD COVER.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRES BUILDS OVER THE AREA TODAY. VFR THROUGH THE TAF PERIOD.
NORTHERLY WINDS WILL BRIEFLY BECOME L/V 15-16Z AS HIGH PRES MOVES
OVERHEAD...THEN WILL SHIFT TO THE SOUTH AT AROUND 10 KT WITH HIGH
PRES OVER THE AREA THIS AFTERNOON. SOUTH WINDS FORECAST FIRST
FOR COASTAL CT TERMINALS AROUND 17Z...THEN KJFK...KISP AROUND 18Z
AND KLGA NEAR 19-20Z WITH INLAND TERMINALS SUCH AS KEWR/KTEB/KHPN
LAST AT ABOUT 20Z. WINDS DIMINISH AFTER SUNSET.
SOME LIGHT PRECIP MAY SPREAD INTO THE TERMINALS LATE TONIGHT. WILL
NOT INCLUDE IN TAF PACKAGE AT THIS TIME DUE TO LOW CONFIDENCE IN
PRECIP OCCURRING...AND LOW CONFIDENCE ON IMPACTS FROM ANY PRECIP
THAT WOULD DEVELOP.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KEWR FCSTER COMMENTS: HIGH CONFIDENCE IN VFR. LOWER CONFIDENCE IN
WINDS. AMENDMENTS POSSIBLE TIMING OF SOUTHERLY WIND SHIFT...WHICH
COULD OCCUR WITHIN AN HOUR OR TWO OF FORECASTED TIME.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KJFK FCSTER COMMENTS: HIGH CONFIDENCE IN VFR. LOWER CONFIDENCE IN
WINDS. AMENDMENTS POSSIBLE TIMING OF SOUTHERLY WIND SHIFT...WHICH
COULD OCCUR WITHIN AN HOUR OF FORECASTED TIME.
KLGA FCSTER COMMENTS: HIGH CONFIDENCE IN VFR. LOWER CONFIDENCE IN
WINDS. AMENDMENTS POSSIBLE TIMING OF SOUTHERLY WIND SHIFT...WHICH
COULD OCCUR WITHIN AN HOUR OR TWO OF FORECASTED TIME.
KTEB FCSTER COMMENTS: HIGH CONFIDENCE IN VFR. LOWER CONFIDENCE IN
WINDS. AMENDMENTS POSSIBLE TIMING OF SOUTHERLY WIND SHIFT...WHICH
COULD OCCUR WITHIN AN HOUR OR TWO OF FORECASTED TIME.
KHPN FCSTER COMMENTS: HIGH CONFIDENCE IN VFR. LOWER CONFIDENCE IN
WINDS. AMENDMENTS POSSIBLE TIMING OF SOUTHERLY WIND SHIFT...WHICH
COULD OCCUR WITHIN AN HOUR OR TWO OF FORECASTED TIME.
KISP FCSTER COMMENTS: HIGH CONFIDENCE IN VFR. LOWER CONFIDENCE IN
WINDS. AMENDMENTS POSSIBLE TIMING OF SOUTHERLY WIND SHIFT...WHICH
COULD OCCUR WITHIN AN HOUR OF FORECASTED TIME.
OUTLOOK FOR 14Z THURSDAY THROUGH SUNDAY...
.THU-FRI NIGHT...VFR.
.SAT...CIGS BELOW 3000 FT POSSIBLE.
.SUN...IFR POSSIBLE IN RAIN. GUSTY NE WINDS POSSIBLE AS WELL.
&&
.MARINE...
MINOR CHANGES MADE TO THE GRIDS TO REFLECT THE LATEST TRENDS IN
OBSERVATIONS AND GUIDANCE. FORECAST APPEARS ON TRACK.
HIGH PRESSURE OVER THE REGION WILL HELP TO KEEP CONDITIONS ON THE
WATERS SUB-SCA THROUGH THURSDAY. WINDS WILL BEGIN INCREASING FROM THE
SOUTH THURSDAY...BUT GUSTS SHOULD REMAIN LESS THAN 20 KTS. SEAS WILL
ALSO BEGIN BUILDING WITH THE INCREASING WINDS...WITH UP TO 5 FT
SEAS POSSIBLE BY THURSDAY NIGHT ON THE OCEAN WATERS.
A PROLONGED SOUTHERLY FLOW THU NIGHT INTO SAT WILL RESULT IN SEAS
JUST BELOW SCA CRITERIA ON THE OCEAN. THE FORECAST CHALLENGE AT THIS
TIME IS WITH THE LOW TRACK LATE IN THE WEEKEND. MODELS HAVE TRENDED
DEEPER AND FARTHER WEST WITH THE LOW TRACK. SHOULD THIS HAPPEN...A
WIND SHIFT TO THE NE ON SUN WOULD NOT HAPPEN. PREFER TO SEE RUN TO
RUN CONTINUITY WITH THE 12Z MODEL CYCLE BEFORE DISCOUNTING THE WIND
SHIFT AND KEEPING THE FLOW SOUTHERLY. REGARDLESS...A STRENGTHENING
SOUTHERLY FLOW WITH A LONG FETCH WOULD ALSO PUSH THE SEAS TO ABOVE 5
FT.
&&
.FIRE WEATHER...
DRY CONDITIONS CONTINUE INTO TODAY...WITH RELATIVE HUMIDITY LEVELS
IN THE 20-35 PERCENT RANGE. HOWEVER...AS HIGH PRESSURE MOVES
OVERHEAD...WINDS AND GUSTS WILL DIMINISH...KEEPING SUSTAINED WINDS
LESS THAN 15 MPH AND GUSTS UNDER 20 MPH. WHILE THE FIRE WEATHER
THREAT WILL REMAIN ELEVATED...WE ARE NOT EXPECTED TO MEET WARNING
CRITERIA.
&&
.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION EXPECTED THROUGH THE END OF THE WEEK. THERE
IS THE POTENTIAL FOR SIGNIFICANT RAINFALL ACROSS THE REGION FROM
THIS WEEKEND INTO EARLY NEXT WEEK.
SEVERE DROUGHT CONDITIONS HAVE DEVELOPED OVER SOUTHERN CT AND
LONG ISLAND. PLEASE REFER TO THE DROUGHT INFORMATION STATEMENT
FOR MORE INFORMATION.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/SEARS/DW
NEAR TERM...MALOIT
SHORT TERM...SEARS
LONG TERM...DW
AVIATION...JM/MPS
MARINE...MALOIT/SEARS/DW
FIRE WEATHER...SEARS/MALOIT
HYDROLOGY...DW
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
106 PM EDT WED APR 18 2012
.SYNOPSIS...
HIGH PRESSURE ACROSS SOUTHERN CANADA TODAY WILL MOVE EASTWARD OFF
THE NEW ENGLAND COAST BY THURSDAY. MEANWHILE...A WEAK DISTURBANCE IS
THEN FORECAST TO TRACK SOUTH OF THE AREA TODAY INTO THURSDAY.
HIGH PRESSURE BUILDS BACK IN FOR THURSDAY AND THURSDAY NIGHT BEFORE
SHIFTING FARTHER TO THE EAST FRIDAY. THE NEXT COLD FRONT MOVES IN
DURING SATURDAY, HOWEVER AN AREA LOW LOW PRESSURE ALONG THIS FRONT
TRACKING TO OUR SOUTH WILL SLOWLY MOVE NORTHEASTWARD SUNDAY AND
MONDAY. THIS SYSTEM IS THEN FORECAST TO BE NEAR NEW ENGLAND TUESDAY
AS HIGH PRESSURE BUILDS TOWARD THE OHIO VALLEY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE AREA OF RAIN OVERRUNNING THE COOLER AIR NEAR THE SURFACE
CONTINUES TO MAKE PROGRESS INTO THE NORTHEAST DELAWARE AND
SOUTHERN DELAWARE. MOST OBSERVATIONS ARE SHOWING VERY LIGHT
RAIN...AND THIS MAKES SENSE CONSIDERING THAT THE 1200 UTC
SOUNDINGS SHOW DRY AIR UP THROUGH THE MID LEVELS. THE LATEST HRRR
RUN IS A BIT BEHIND REALITY THIS MORNING...BUT IS SHOWING A
NORTHEAST TREND WITH THE LIGHT RAIN.
CONSIDERING HOW DRY THE LOW LEVELS ARE...THE EXTENT AND AMOUNT OF
PRECIPITATION DEPICTED BY THE LATEST HRRR SEEMS A BIT OVERDONE.
HOWEVER...THE RADAR PRESENTATION (AND GROUND TRUTH BELOW THAT
ACROSS NORTHEAST MARYLAND) SUGGESTS THAT THE AREAL COVERAGE OF THE
RAIN NEEDED TO BE EXTENDED A BIT MORE ON THE LATEST FORECAST
UPDATE. IN ANY EVENT...THE RAINFALL SHOULD BE LIGHT (LESS THAN
0.10 INCHES ACROSS SOUTHERNMOST AREAS...AND PERHAPS NOT MUCH MORE
THAN A TRACE ACROSS SOUTH CENTRAL NEW JERSEY.
THE MID LEVEL CLOUDINESS IS NOT COMPLETELY OPAQUE (BASED ON THE
OBSERVATION HERE AT THE OFFICE)...AND THERE IS SOME SUNSHINE
ACROSS PORTIONS OF NEW JERSEY AND EASTERN PENNSYLVANIA. THIS
PROBABLY FILLS IN AS THE RAIN MOVES NORTHEAST. THE CLOUD COVER
SHOULD KEEP TEMPERATURES DOWN...ESPECIALLY ACROSS SOUTHERN AREAS.
THE 1200 UTC SOUNDINGS SHOW FULL SUN TEMPERATURES IN THE MID
60S...AND BASED ON CURRENT HOURLY TEMPERATURES...THAT APPEARS TOO
HIGH. ACCORDINGLY...HIGH TEMPERATURES WERE TRIMMED A BIT MORE
ACROSS SOUTHERN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AN IMPULSE IN THE WESTERLY MID LEVEL FLOW IS FORECAST TO PASS
OVERHEAD THIS EVENING, WITH A MORE SUBSTANTIAL MID LEVEL SHORT WAVE
EXPECTED TO MOVE OFF THE MIDDLE ATLANTIC COAST OVERNIGHT. IT SHOULD
REMAIN MOSTLY CLOUDY IN OUR REGION TONIGHT WITH A CONTINUED CHANCE
OR SLIGHT CHANCE OF LIGHT SHOWERS, MAINLY IN OUR SOUTHERN COUNTIES.
THE WIND IS EXPECTED TO BE MOSTLY LIGHT AND VARIABLE, AND
TEMPERATURES SHOULD FALL INTO THE 40S AT MOST LOCATIONS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE BEGINNING OF THE LONG TERM IS DRY AS HIGH PRESSURE BUILDS BACK
ACROSS THE AREA. A FEW LINGERING CLOUDS WILL BE ACROSS ERN NJ AND
THE DELMARVA THU MORNING ASSOCIATED WITH THE DEPARTING WEAK LOW
FROM THE SHORT TERM...NO RAINFALL IS EXPECTED HOWEVER. IT WILL BE
SEASONABLY MILD ACROSS THE AREA THU WITH HIGHS IN THE MID TO UPPER
60S. THE DRY WEATHER WILL CARRY INTO FRI WITH EVEN MILDER
TEMPERATURES. HIGHS ON FRI WILL BE IN THE LOW TO MID 70S.
UNSETTLED WEATHER WILL BE ACROSS THE AREA FRI NIGHT INTO THE
WEEKEND. THE NEXT SYSTEM DOES APPEAR TO BE TRENDING A BIT SLOWER. I
KEPT THE SLGT CHC POPS IN FOR FRI NIGHT...ONLY TO MAINTAIN THE SENSE
OF CONTINUITY ACROSS THE CWA`S. IT WILL PROBABLY END UP BEING DRY
FRI NIGHT. THE STEADIER RAIN WILL PROBABLY ARRIVE LATER SAT WITH CHC
POPS IN THE GRIDS FOR THE AFTERNOON. AGAIN THE TREND TOWARD A LOWER
POPS OR A DRY FCST FOR SAT COULD STILL HAPPEN. THE EC/GFS SHOW THE
BULK OF THE RAIN FOR SAT NIGHT INTO MON WITH THE POTENTIAL FOR A
SOAKING RAIN DURING THE PERIOD. TOTAL QPF ENDING 12Z COULD BE 2 TO 3
INCHES NORTH/WEST AND CENTRAL AREAS WITH 1 TO 2 INCHES DELMARVA AND
ERN NJ. IT APPEARS THE RAINS WILL COME IN A LONG ENOUGH STRETCH TO
PRECLUDE ANY FLOODING PROBLEMS HOWEVER. HIGHS SUN AND MON WILL
MOSTLY BE IN THE UPPER 50S TO LOW 60S WITH THE CLOUDS AND RAIN.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS AFTERNOON AS A BATCH OF RAIN
MOVES NORTHEAST THROUGH THE SOUTHERN TERMINALS. VFR CONDITIONS ARE
EXPECTED TO CONTINUE INTO THE EVENING AS THE FIRST BATCH OF RAIN
PASSES MAINLY SOUTH OF KPHL...WITH CEILINGS LOWERING TO NEAR 5000
FEET BY ABOUT 0100 UTC THURSDAY.
AS ANOTHER BATCH OF RAIN PASSES MAINLY SOUTH OF THE AREA TONIGHT
WITH SURFACE LOW PRESSURE...VFR CONDITIONS ARE EXPECTED. STATISTICAL
GUIDANCE IS SHOWING THE POTENTIAL FOR MVFR CEILINGS FOR SOUTHERN
TERMINALS (MAINLY SOUTH OF KPHL) BETWEEN 0900 UTC AND 1300 UTC
THURSDAY. GIVEN THE CEILINGS NOW IN CENTRAL VIRGINIA...THIS IS
POSSIBLE FOR KMIV AND KILG...BUT FOR NOW MVFR CEILINGS WERE NOT
INCLUDED FOR KPHL.
THE LOWER VFR CEILINGS SHOULD START TO BREAK AFTER 1400 UTC ACROSS
THE SOUTH...WITH VFR CONDITIONS ELSEWHERE. THE LIGHT GRADIENT SHOULD
ALLOW WINDS TO SWING AROUND TO SOUTH AND SOUTHWEST BY AFTERNOON...
GENERALLY LESS THAN 10 KNOTS.
OUTLOOK...
THU THRU FRI NIGHT...MOSTLY VFR.
SAT THRU SUNDAY...DETERIORATING CIGS/VSBYS WITH SHOWERS. LOW/MVFR
OR IFR POSSIBLE BY SUN.
&&
.MARINE...
THE GRADIENT HAS BACKED OFF CONSIDERABLY ACROSS THE NORTHERN OCEAN
WATERS HIS AFTERNOON...AND LOCAL SEA BREEZE CIRCULATIONS ARE
POSSIBLE WITH WINDS GENERALLY LESS THAN 10 KNOTS. FURTHER
SOUTH...THE NORTHEAST GRADIENT SI SLOWLY BACKING OFF...AND WINDS
SHOULD REMAIN BELOW 15 KNOTS. THE NORTHEAST SWELL IS STARTING TO
BUILD AT 44009...BUT FOR NOW SEAS SHOULD REMAIN BELOW 4 FEET THIS
AFTERNOON.
WAVE HEIGHTS ON OUR OCEAN WATERS SHOULD REMAIN AROUND 2 TO 3 FEET.
ON DELAWARE BAY, WAVE HEIGHTS SHOULD BE 2 FEET OR LESS FOR TODAY AND
TONIGHT.
OUTLOOK...
SUB-SCA CONDITIONS EXPECTED THU THRU SAT MORNING WITH WEAK HIGH
PRESSURE ACROSS THE WATERS. AN APPROACHING LOW/FRONT WILL CAUSE
INCREASING WINDS/SEAS LATER SAT WHICH COULD BRING SCA CONDITIONS.
ANY SCA CONDITIONS COULD LAST INTO SUN WITH THE SYSTEM MOVING
RATHER SLOWLY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...HAYES
SHORT TERM...IOVINO
LONG TERM...O`HARA
AVIATION...HAYES/O`HARA
MARINE...IOVINO
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1008 AM EDT WED APR 18 2012
.SYNOPSIS...
HIGH PRESSURE ACROSS SOUTHERN CANADA TODAY WILL MOVE EASTWARD OFF
THE NEW ENGLAND COAST BY THURSDAY. MEANWHILE...A WEAK DISTURBANCE IS
THEN FORECAST TO TRACK SOUTH OF THE AREA TODAY INTO THURSDAY.
HIGH PRESSURE BUILDS BACK IN FOR THURSDAY AND THURSDAY NIGHT BEFORE
SHIFTING FARTHER TO THE EAST FRIDAY. THE NEXT COLD FRONT MOVES IN
DURING SATURDAY, HOWEVER AN AREA LOW LOW PRESSURE ALONG THIS FRONT
TRACKING TO OUR SOUTH WILL SLOWLY MOVE NORTHEASTWARD SUNDAY AND
MONDAY. THIS SYSTEM IS THEN FORECAST TO BE NEAR NEW ENGLAND TUESDAY
AS HIGH PRESSURE BUILDS TOWARD THE OHIO VALLEY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE AREA OF RAIN OVERRUNNING THE COOLER AIR NEAR THE SURFACE
CONTINUES TO MAKE PROGRESS INTO THE NORTHEAST DELAWARE AND
SOUTHERN DELAWARE. MOST OBSERVATIONS ARE SHOWING VERY LIGHT
RAIN...AND THIS MAKES SENSE CONSIDERING THAT THE 1200 UTC
SOUNDINGS SHOW DRY AIR UP THROUGH THE MID LEVELS. THE LATEST HRRR
RUN IS A BIT BEHIND REALITY THIS MORNING...BUT IS SHOWING A
NORTHEAST TREND WITH THE LIGHT RAIN.
CONSIDERING HOW DRY THE LOW LEVELS ARE...THE EXTENT AND AMOUNT OF
PRECIPITATION DEPICTED BY THE LATEST HRRR SEEMS A BIT OVERDONE.
HOWEVER...THE RADAR PRESENTATION (AND GROUND TRUTH BELOW THAT
ACROSS NORTHEAST MARYLAND) SUGGESTS THAT THE AREAL COVERAGE OF THE
RAIN NEEDED TO BE EXTENDED A BIT MORE ON THE LATEST FORECAST
UPDATE. IN ANY EVENT...THE RAINFALL SHOULD BE LIGHT (LESS THAN
0.10 INCHES ACROSS SOUTHERNMOST AREAS...AND PERHAPS NOT MUCH MORE
THAN A TRACE ACROSS SOUTH CENTRAL NEW JERSEY.
THE MID LEVEL CLOUDINESS IS NOT COMPLETELY OPAQUE (BASED ON THE
OBSERVATION HERE AT THE OFFICE)...AND THERE IS SOME SUNSHINE
ACROSS PORTIONS OF NEW JERSEY AND EASTERN PENNSYLVANIA. THIS
PROBABLY FILLS IN AS THE RAIN MOVES NORTHEAST. THE CLOUD COVER
SHOULD KEEP TEMPERATURES DOWN...ESPECIALLY ACROSS SOUTHERN AREAS.
THE 1200 UTC SOUNDINGS SHOW FULL SUN TEMPERATURES IN THE MID
60S...AND BASED ON CURRENT HOURLY TEMPERATURES...THAT APPEARS TOO
HIGH. ACCORDINGLY...HIGH TEMPERATURES WERE TRIMMED A BIT MORE
ACROSS SOUTHERN AREAS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AN IMPULSE IN THE WESTERLY MID LEVEL FLOW IS FORECAST TO PASS
OVERHEAD THIS EVENING, WITH A MORE SUBSTANTIAL MID LEVEL SHORT WAVE
EXPECTED TO MOVE OFF THE MIDDLE ATLANTIC COAST OVERNIGHT. IT SHOULD
REMAIN MOSTLY CLOUDY IN OUR REGION TONIGHT WITH A CONTINUED CHANCE
OR SLIGHT CHANCE OF LIGHT SHOWERS, MAINLY IN OUR SOUTHERN COUNTIES.
THE WIND IS EXPECTED TO BE MOSTLY LIGHT AND VARIABLE, AND
TEMPERATURES SHOULD FALL INTO THE 40S AT MOST LOCATIONS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE BEGINNING OF THE LONG TERM IS DRY AS HIGH PRESSURE BUILDS BACK
ACROSS THE AREA. A FEW LINGERING CLOUDS WILL BE ACROSS ERN NJ AND
THE DELMARVA THU MORNING ASSOCIATED WITH THE DEPARTING WEAK LOW
FROM THE SHORT TERM...NO RAINFALL IS EXPECTED HOWEVER. IT WILL BE
SEASONABLY MILD ACROSS THE AREA THU WITH HIGHS IN THE MID TO UPPER
60S. THE DRY WEATHER WILL CARRY INTO FRI WITH EVEN MILDER
TEMPERATURES. HIGHS ON FRI WILL BE IN THE LOW TO MID 70S.
UNSETTLED WEATHER WILL BE ACROSS THE AREA FRI NIGHT INTO THE
WEEKEND. THE NEXT SYSTEM DOES APPEAR TO BE TRENDING A BIT SLOWER. I
KEPT THE SLGT CHC POPS IN FOR FRI NIGHT...ONLY TO MAINTAIN THE SENSE
OF CONTINUITY ACROSS THE CWA`S. IT WILL PROBABLY END UP BEING DRY
FRI NIGHT. THE STEADIER RAIN WILL PROBABLY ARRIVE LATER SAT WITH CHC
POPS IN THE GRIDS FOR THE AFTERNOON. AGAIN THE TREND TOWARD A LOWER
POPS OR A DRY FCST FOR SAT COULD STILL HAPPEN. THE EC/GFS SHOW THE
BULK OF THE RAIN FOR SAT NIGHT INTO MON WITH THE POTENTIAL FOR A
SOAKING RAIN DURING THE PERIOD. TOTAL QPF ENDING 12Z COULD BE 2 TO 3
INCHES NORTH/WEST AND CENTRAL AREAS WITH 1 TO 2 INCHES DELMARVA AND
ERN NJ. IT APPEARS THE RAINS WILL COME IN A LONG ENOUGH STRETCH TO
PRECLUDE ANY FLOODING PROBLEMS HOWEVER. HIGHS SUN AND MON WILL
MOSTLY BE IN THE UPPER 50S TO LOW 60S WITH THE CLOUDS AND RAIN.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. ISOLATED TO
SCATTERED LIGHT RAIN SHOWERS ARE POSSIBLE, ESPECIALLY AROUND KILG,
KMIV AND KACY FROM THIS AFTERNOON INTO TONIGHT. HOWEVER, THE RAIN
SHOWERS SHOULD HAVE LITTLE IMPACT AT THE TAF SITES.
A NORTH WIND AROUND 6 TO 10 KNOTS THIS MORNING IS EXPECTED TO BECOME
VARIABLE FOR THIS AFTERNOON AT 6 KNOTS OR LESS. WITH HIGH PRESSURE
NOSING INTO OUR REGION FROM THE NORTH, A LIGHT WIND IS ANTICIPATED
FOR TONIGHT, AS WELL.
OUTLOOK...
THU THRU FRI NIGHT...MOSTLY VFR.
SAT THRU SUNDAY...DETERIORATING CIGS/VSBYS WITH SHOWERS. LOW/MVFR
OR IFR POSSIBLE BY SUN.
&&
.MARINE...
A SECONDARY COLD FRONT DROPPED THROUGH OUR REGION DURING THE NIGHT.
A NORTH WIND AROUND 10 TO 15 KNOTS IS ANTICIPATED FOR THIS MORNING.
THE WIND SHOULD VEER TOWARD THE EAST THIS AFTERNOON WITH SPEEDS
DECREASING TO 5 TO 10 KNOTS FOR TONIGHT AS HIGH PRESSURE NOSES INTO
OUR REGION FROM THE NORTH. THE WIND DIRECTION MAY BECOME VARIABLE ON
OUR NORTHERN WATERS AT THAT TIME.
WAVE HEIGHTS ON OUR OCEAN WATERS SHOULD REMAIN AROUND 2 TO 3 FEET.
ON DELAWARE BAY, WAVE HEIGHTS SHOULD BE 2 FEET OR LESS FOR TODAY AND
TONIGHT.
OUTLOOK...
SUB-SCA CONDITIONS EXPECTED THU THRU SAT MORNING WITH WEAK HIGH
PRESSURE ACROSS THE WATERS. AN APPROACHING LOW/FRONT WILL CAUSE
INCREASING WINDS/SEAS LATER SAT WHICH COULD BRING SCA CONDITIONS.
ANY SCA CONDITIONS COULD LAST INTO SUN WITH THE SYSTEM MOVING
RATHER SLOWLY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...HAYES
SHORT TERM...IOVINO
LONG TERM...O`HARA
AVIATION...IOVINO
MARINE...IOVINO
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
840 AM EDT WED APR 18 2012
.SYNOPSIS...
HIGH PRESSURE ACROSS SOUTHERN CANADA TODAY WILL MOVE EASTWARD OFF
THE NEW ENGLAND COAST BY THURSDAY. MEANWHILE...A WEAK DISTURBANCE IS
THEN FORECAST TO TRACK SOUTH OF THE AREA TODAY INTO THURSDAY.
HIGH PRESSURE BUILDS BACK IN FOR THURSDAY AND THURSDAY NIGHT BEFORE
SHIFTING FARTHER TO THE EAST FRIDAY. THE NEXT COLD FRONT MOVES IN
DURING SATURDAY, HOWEVER AN AREA LOW LOW PRESSURE ALONG THIS FRONT
TRACKING TO OUR SOUTH WILL SLOWLY MOVE NORTHEASTWARD SUNDAY AND
MONDAY. THIS SYSTEM IS THEN FORECAST TO BE NEAR NEW ENGLAND TUESDAY
AS HIGH PRESSURE BUILDS TOWARD THE OHIO VALLEY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
DESPITE THE DRY LOW LEVELS DEPICTED ON THE 18/1200 UTC KAPG
SOUNDING...RAIN IS PROGRESSING INTO PORTIONS OF NORTHEAST MARYLAND
AND SOON SOUTHERN DELAWARE. MOISTURE IS OVERRUNNING THE COOL
AIRMASS NEAR THE SURFACE...ALLOWING THE RAIN TO SPREAD NORTHEAST
AHEAD OF THE SHORT WAVE OVER THE LOWER OHIO VALLEY.
EXTRAPOLATION OF THE AREA OF RAIN (WHICH IS SUPPORTED BY THE
LATEST HRRR PRECIPITATION FIELDS) BRINGS IT INTO NORTHEAST
MARYLAND AND MUCH OF DELAWARE...AND THE CHANCE OF RAIN WAS
INCREASED IN THESE AREAS FOR THIS MORNING AND EARLY THIS AFTERNOON.
THE AREAL EXTENT OF THE RAIN WAS ALSO INCREASED TO INCLUDE MORE OF
SOUTHEAST PENNSYLVANIA AND SOUTHERN NEW JERSEY...AGAIN BASED ON
THE HRRR PRECIPITATION FIELDS.
THE MID CLOUDS HAVE ALREADY SLOWED THE RISE IN TEMPERATURES THIS
MORNING. FORECAST HIGHS HAVE BEEN DROPPED A BIT TO ACCOUNT FOR THE
MID LEVEL CLOUDINESS...ESPECIALLY ACROSS THE SOUTHERN HALF OF THE
AREA...AND MAY NOT BE ENOUGH BASED ON TRENDS. ALSO...HOURLY
TEMPERATURES WERE DROPPED A BIT IN DEFERENCE TO THE CLOUDINESS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
AN IMPULSE IN THE WESTERLY MID LEVEL FLOW IS FORECAST TO PASS
OVERHEAD THIS EVENING, WITH A MORE SUBSTANTIAL MID LEVEL SHORT WAVE
EXPECTED TO MOVE OFF THE MIDDLE ATLANTIC COAST OVERNIGHT. IT SHOULD
REMAIN MOSTLY CLOUDY IN OUR REGION TONIGHT WITH A CONTINUED CHANCE
OR SLIGHT CHANCE OF LIGHT SHOWERS, MAINLY IN OUR SOUTHERN COUNTIES.
THE WIND IS EXPECTED TO BE MOSTLY LIGHT AND VARIABLE, AND
TEMPERATURES SHOULD FALL INTO THE 40S AT MOST LOCATIONS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE BEGINNING OF THE LONG TERM IS DRY AS HIGH PRESSURE BUILDS BACK
ACROSS THE AREA. A FEW LINGERING CLOUDS WILL BE ACROSS ERN NJ AND
THE DELMARVA THU MORNING ASSOCIATED WITH THE DEPARTING WEAK LOW
FROM THE SHORT TERM...NO RAINFALL IS EXPECTED HOWEVER. IT WILL BE
SEASONABLY MILD ACROSS THE AREA THU WITH HIGHS IN THE MID TO UPPER
60S. THE DRY WEATHER WILL CARRY INTO FRI WITH EVEN MILDER
TEMPERATURES. HIGHS ON FRI WILL BE IN THE LOW TO MID 70S.
UNSETTLED WEATHER WILL BE ACROSS THE AREA FRI NIGHT INTO THE
WEEKEND. THE NEXT SYSTEM DOES APPEAR TO BE TRENDING A BIT SLOWER. I
KEPT THE SLGT CHC POPS IN FOR FRI NIGHT...ONLY TO MAINTAIN THE SENSE
OF CONTINUITY ACROSS THE CWA`S. IT WILL PROBABLY END UP BEING DRY
FRI NIGHT. THE STEADIER RAIN WILL PROBABLY ARRIVE LATER SAT WITH CHC
POPS IN THE GRIDS FOR THE AFTERNOON. AGAIN THE TREND TOWARD A LOWER
POPS OR A DRY FCST FOR SAT COULD STILL HAPPEN. THE EC/GFS SHOW THE
BULK OF THE RAIN FOR SAT NIGHT INTO MON WITH THE POTENTIAL FOR A
SOAKING RAIN DURING THE PERIOD. TOTAL QPF ENDING 12Z COULD BE 2 TO 3
INCHES NORTH/WEST AND CENTRAL AREAS WITH 1 TO 2 INCHES DELMARVA AND
ERN NJ. IT APPEARS THE RAINS WILL COME IN A LONG ENOUGH STRETCH TO
PRECLUDE ANY FLOODING PROBLEMS HOWEVER. HIGHS SUN AND MON WILL
MOSTLY BE IN THE UPPER 50S TO LOW 60S WITH THE CLOUDS AND RAIN.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. ISOLATED TO
SCATTERED LIGHT RAIN SHOWERS ARE POSSIBLE, ESPECIALLY AROUND KILG,
KMIV AND KACY FROM THIS AFTERNOON INTO TONIGHT. HOWEVER, THE RAIN
SHOWERS SHOULD HAVE LITTLE IMPACT AT THE TAF SITES.
A NORTH WIND AROUND 6 TO 10 KNOTS THIS MORNING IS EXPECTED TO BECOME
VARIABLE FOR THIS AFTERNOON AT 6 KNOTS OR LESS. WITH HIGH PRESSURE
NOSING INTO OUR REGION FROM THE NORTH, A LIGHT WIND IS ANTICIPATED
FOR TONIGHT, AS WELL.
OUTLOOK...
THU THRU FRI NIGHT...MOSTLY VFR.
SAT THRU SUNDAY...DETERIORATING CIGS/VSBYS WITH SHOWERS. LOW/MVFR
OR IFR POSSIBLE BY SUN.
&&
.MARINE...
A SECONDARY COLD FRONT DROPPED THROUGH OUR REGION DURING THE NIGHT.
A NORTH WIND AROUND 10 TO 15 KNOTS IS ANTICIPATED FOR THIS MORNING.
THE WIND SHOULD VEER TOWARD THE EAST THIS AFTERNOON WITH SPEEDS
DECREASING TO 5 TO 10 KNOTS FOR TONIGHT AS HIGH PRESSURE NOSES INTO
OUR REGION FROM THE NORTH. THE WIND DIRECTION MAY BECOME VARIABLE ON
OUR NORTHERN WATERS AT THAT TIME.
WAVE HEIGHTS ON OUR OCEAN WATERS SHOULD REMAIN AROUND 2 TO 3 FEET.
ON DELAWARE BAY, WAVE HEIGHTS SHOULD BE 2 FEET OR LESS FOR TODAY AND
TONIGHT.
OUTLOOK...
SUB-SCA CONDITIONS EXPECTED THU THRU SAT MORNING WITH WEAK HIGH
PRESSURE ACROSS THE WATERS. AN APPROACHING LOW/FRONT WILL CAUSE
INCREASING WINDS/SEAS LATER SAT WHICH COULD BRING SCA CONDITIONS.
ANY SCA CONDITIONS COULD LAST INTO SUN WITH THE SYSTEM MOVING
RATHER SLOWLY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...IOVINO/HAYES
SHORT TERM...IOVINO
LONG TERM...O`HARA
AVIATION...IOVINO
MARINE...IOVINO
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1208 PM CDT WED APR 18 2012
.DISCUSSION...
ISSUED 1003 AM CDT WED APR 18 2012
BAND OF RAIN SHOWERS ACROSS EASTERN IOWA HAS BEEN BREAKING UP THE
LAST FEW HOURS...WITH MAINLY THE ASSOCIATED ALTOCUMULUS CLOUDS
STILL EXPECTED TO AFFECT THE NORTHERN CWA LATER TODAY. LATEST NAM
AND HRRR MODELS HOLD ON TO ENOUGH OF THE PRECIPITATION TO JUSTIFY
HOLDING ONTO THE EXISTING 20 PERCENT RAIN CHANCES ACROSS THE FAR
NORTH THIS AFTERNOON. HAVE SENT SOME MINOR TWEAKS TO THE HOURLY
TEMPERATURE/SKY GRIDS...BUT NO CHANGE IS NEEDED TO THE WORDED
FORECASTS AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 1208 PM CDT WED APR 18 2012
BAND OF SHOWERS ACROSS SOUTHEAST IOWA CONTINUES TO DIMINISH AS IT
APPROACHES THE MISSISSIPPI RIVER. LATEST NAM/HRRR CONTINUES TO
HINT AT SOME REDEVELOPMENT MAINLY OVER NORTHERN ILLINOIS. CANNOT
RULE OUT A FEW BRIEF SHOWERS NEAR OR NORTH OF KPIA THIS
AFTERNOON...BUT COVERAGE THAT FAR SOUTH SHOULD BE SPARSE ENOUGH
TO PRECLUDE MENTION IN THE TAFS AT THIS TIME.
IN GENERAL...GUSTY SOUTH/SOUTHWEST WINDS TO CONTINUE THIS
AFTERNOON AT ALL SITES...WITH THE TYPICAL DIMINISHING EARLY THIS
EVENING. PERIODS OF CLOUDINESS SHOULD REMAIN FAIRLY ELEVATED...
MAINLY 9000 FEET OR ABOVE. AN APPROACHING COLD FRONT IS EXPECTED
TO BECOME STATIONARY OVER FAR NORTHERN ILLINOIS THIS EVENING...AND
THIS WILL KEEP WINDS SOUTHERLY THROUGH THURSDAY MORNING.
HOWEVER...ASIDE FROM THE ISOLATED AFTERNOON SHOWERS MENTIONED
EARLIER...MAIN PRECIPITATION THREAT SHOULD REMAIN NORTHWEST OF THE
TAF SITES.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 252 AM CDT WED APR 18 2012
SHORT TERM...TODAY THROUGH FRIDAY
LOW PRESSURE ANALYZED OVER WESTERN MINNESOTA AT 06Z WILL TRACK
NORTHEASTWARD TODAY...REACHING LAKE SUPERIOR BY LATE THIS
AFTERNOON. TRAILING COLD FRONT WILL GRADUALLY SETTLE SOUTHWARD
TOWARD ILLINOIS...WITH HIGH-RES MODELS SUGGESTING WIDELY SCATTERED
SHOWERS/STORMS DEVELOPING ALONG IT AFTER 21Z. WITH BOUNDARY
EXPECTED TO REMAIN WELL TO THE NORTH...HAVE ONLY INCLUDED A SLIGHT
CHANCE POP ACROSS THE FAR NORTHERN KILX CWA AROUND GALESBURG.
FURTHER SOUTH ACROSS THE REMAINDER OF THE AREA...EXPECT MOSTLY
SUNNY AND DRY CONDITIONS. AS PRESSURE GRADIENT TIGHTENS BETWEEN
HIGH ANCHORED OVER THE OHIO RIVER VALLEY AND APPROACHING COLD
FRONT...GUSTY S/SW WINDS WILL DEVELOP THIS AFTERNOON. FORECAST
SOUNDINGS AND NUMERIC GUIDANCE INDICATE GUSTS UP TO 25
MPH...PARTICULARLY ALONG/WEST OF THE I-55 CORRIDOR.
FRONT WILL STALL ACROSS NORTHERN ILLINOIS TONIGHT INTO THURSDAY...AS
IT BECOMES PARALLEL TO THE ZONAL UPPER FLOW. AS SUCH...BEST
FORCING FOR SHOWERS/STORMS WILL REMAIN TO THE NORTH OF CENTRAL
ILLINOIS ACROSS IOWA INTO NORTHERN ILLINOIS. HAVE MAINTAINED LOW
CHANCE POPS IN CLOSER PROXIMITY TO THE BOUNDARY FROM PEORIA
NORTHWARD...BUT HAVE GONE WITH A DRY FORECAST FURTHER SOUTH ACROSS
THE REST OF THE AREA. PARTIAL SUNSHINE AND A CONTINUED STRONG
SOUTHERLY FLOW WILL HELP PUSH HIGH TEMPERATURES WELL INTO THE 70S
ON THURSDAY.
MODELS CONTINUE TO SHOW SHORT-WAVE CROSSING THE ROCKIES AND SLOWLY
AMPLIFYING OVER THE MISSISSIPPI RIVER VALLEY TOWARD THE END OF
THE WEEK...GRADUALLY PUSHING THE STALLED FRONTAL BOUNDARY FURTHER
SOUTH AND EAST. THE GENERAL TREND OVER THE PAST SEVERAL MODEL RUNS
HAS BEEN TO SLOW DOWN THIS PROCESS AS UPPER WAVE DIGS INTO THE
DEEP SOUTH AND CUTS OFF ALONG THE GULF COAST. 00Z 18 APR SUITE HAS
CONTINUED THE SLOWING TREND...NOW FEATURING FRONT REMAINING IN THE
VICINITY AT LEAST THROUGH FRIDAY NIGHT AND PERHAPS INTO SATURDAY
MORNING ACROSS THE SOUTHEAST CWA. HAVE ADJUSTED POPS
ACCORDINGLY...FOCUSING HIGHEST RAIN CHANCES ACROSS THE ILLINOIS
RIVER VALLEY THURSDAY NIGHT...THEN EVERYWHERE FRIDAY/FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH TUESDAY
DUE TO THE SLOWER DEPARTURE OF THE FRONT...HAVE HELD ON TO LOW
CHANCE POPS ALONG/SOUTH OF I-70 INTO SATURDAY. ELSEWHERE AROUND
THE AREA...DRY AND MUCH COOLER WEATHER WILL BE ON TAP AS
NORTHWESTERLY FLOW PATTERN DEVELOPS ACROSS THE MIDWEST. WITH 850MB
TEMPS DROPPING INTO THE 0 TO 5C RANGE...HIGH TEMPS WILL ONLY REACH
THE 50S ON BOTH SATURDAY AND SUNDAY...WITH OVERNIGHT LOWS DIPPING
INTO THE 30S. FURTHER OUT...MODEL DISCREPANCIES CONCERNING THE
EVOLUTION OF THE EASTERN CONUS TROUGH PERSIST...HOWEVER GENERAL
CONSENSUS POINTS TO A CONTINUED COOL NORTHWESTERLY FLOW ACROSS
ILLINOIS THROUGH AT LEAST EARLY NEXT WEEK.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1003 AM CDT WED APR 18 2012
.DISCUSSION...
ISSUED 1003 AM CDT WED APR 18 2012
BAND OF RAIN SHOWERS ACROSS EASTERN IOWA HAS BEEN BREAKING UP THE
LAST FEW HOURS...WITH MAINLY THE ASSOCIATED ALTOCUMULUS CLOUDS
STILL EXPECTED TO AFFECT THE NORTHERN CWA LATER TODAY. LATEST NAM
AND HRRR MODELS HOLD ON TO ENOUGH OF THE PRECIPITATION TO JUSTIFY
HOLDING ONTO THE EXISTING 20 PERCENT RAIN CHANCES ACROSS THE FAR
NORTH THIS AFTERNOON. HAVE SENT SOME MINOR TWEAKS TO THE HOURLY
TEMPERATURE/SKY GRIDS...BUT NO CHANGE IS NEEDED TO THE WORDED
FORECASTS AT THIS TIME.
GEELHART
&&
.AVIATION...
ISSUED 605 AM CDT WED APR 18 2012
VFR CONDITIONS ARE EXPECTED THROUGH THIS FORECAST PERIOD. A COLD
FRONT TO OUR NORTHWEST WILL SLOWLY APPROACH THE AREA LATE TODAY.
OTHER THAN SOME SCATTERED CU AND MID LEVEL CLOUDS...NOT MUCH IN
THE WAY OF SENSIBLE WEATHER IS EXPECTED ACROSS THE TAF SITES TODAY.
SOME ISOLD CONVECTION WILL BE POSSIBLE NORTH OF PIA AND BMI LATE
TODAY AND TONIGHT BUT WITH THE FRONT EXPECTED TO STALL OUT NORTH
OF OUR AREA LATER IN THE FORECAST PERIOD...RAIN CHANCES WILL REMAIN
NORTH OF THE TAF SITES THRU 12Z THURSDAY. SURFACE WINDS WILL
INCREASE OUT OF THE SOUTH TO SOUTHWEST AT 12 TO 17 KTS WITH A FEW
GUSTS ARND 25 KTS AT TIMES...ESPECIALLY ALONG AND WEST OF A BMI TO
SPI LINE THIS AFTN. WINDS WILL DIMINISH SOME OUT OF THE SOUTH
TONIGHT WITH NO MORE THAN SOME SCT-BKN CIGS AT 8000-10000 FEET...
MAINLY ACROSS THE NORTH.
SMITH
&&
.PREV DISCUSSION...
ISSUED 252 AM CDT WED APR 18 2012
SHORT TERM...TODAY THROUGH FRIDAY
LOW PRESSURE ANALYZED OVER WESTERN MINNESOTA AT 06Z WILL TRACK
NORTHEASTWARD TODAY...REACHING LAKE SUPERIOR BY LATE THIS
AFTERNOON. TRAILING COLD FRONT WILL GRADUALLY SETTLE SOUTHWARD
TOWARD ILLINOIS...WITH HIGH-RES MODELS SUGGESTING WIDELY SCATTERED
SHOWERS/STORMS DEVELOPING ALONG IT AFTER 21Z. WITH BOUNDARY
EXPECTED TO REMAIN WELL TO THE NORTH...HAVE ONLY INCLUDED A SLIGHT
CHANCE POP ACROSS THE FAR NORTHERN KILX CWA AROUND GALESBURG.
FURTHER SOUTH ACROSS THE REMAINDER OF THE AREA...EXPECT MOSTLY
SUNNY AND DRY CONDITIONS. AS PRESSURE GRADIENT TIGHTENS BETWEEN
HIGH ANCHORED OVER THE OHIO RIVER VALLEY AND APPROACHING COLD
FRONT...GUSTY S/SW WINDS WILL DEVELOP THIS AFTERNOON. FORECAST
SOUNDINGS AND NUMERIC GUIDANCE INDICATE GUSTS UP TO 25
MPH...PARTICULARLY ALONG/WEST OF THE I-55 CORRIDOR.
FRONT WILL STALL ACROSS NORTHERN ILLINOIS TONIGHT INTO THURSDAY...AS
IT BECOMES PARALLEL TO THE ZONAL UPPER FLOW. AS SUCH...BEST
FORCING FOR SHOWERS/STORMS WILL REMAIN TO THE NORTH OF CENTRAL
ILLINOIS ACROSS IOWA INTO NORTHERN ILLINOIS. HAVE MAINTAINED LOW
CHANCE POPS IN CLOSER PROXIMITY TO THE BOUNDARY FROM PEORIA
NORTHWARD...BUT HAVE GONE WITH A DRY FORECAST FURTHER SOUTH ACROSS
THE REST OF THE AREA. PARTIAL SUNSHINE AND A CONTINUED STRONG
SOUTHERLY FLOW WILL HELP PUSH HIGH TEMPERATURES WELL INTO THE 70S
ON THURSDAY.
MODELS CONTINUE TO SHOW SHORT-WAVE CROSSING THE ROCKIES AND SLOWLY
AMPLIFYING OVER THE MISSISSIPPI RIVER VALLEY TOWARD THE END OF
THE WEEK...GRADUALLY PUSHING THE STALLED FRONTAL BOUNDARY FURTHER
SOUTH AND EAST. THE GENERAL TREND OVER THE PAST SEVERAL MODEL RUNS
HAS BEEN TO SLOW DOWN THIS PROCESS AS UPPER WAVE DIGS INTO THE
DEEP SOUTH AND CUTS OFF ALONG THE GULF COAST. 00Z 18 APR SUITE HAS
CONTINUED THE SLOWING TREND...NOW FEATURING FRONT REMAINING IN THE
VICINITY AT LEAST THROUGH FRIDAY NIGHT AND PERHAPS INTO SATURDAY
MORNING ACROSS THE SOUTHEAST CWA. HAVE ADJUSTED POPS
ACCORDINGLY...FOCUSING HIGHEST RAIN CHANCES ACROSS THE ILLINOIS
RIVER VALLEY THURSDAY NIGHT...THEN EVERYWHERE FRIDAY/FRIDAY NIGHT.
LONG TERM...SATURDAY THROUGH TUESDAY
DUE TO THE SLOWER DEPARTURE OF THE FRONT...HAVE HELD ON TO LOW
CHANCE POPS ALONG/SOUTH OF I-70 INTO SATURDAY. ELSEWHERE AROUND
THE AREA...DRY AND MUCH COOLER WEATHER WILL BE ON TAP AS
NORTHWESTERLY FLOW PATTERN DEVELOPS ACROSS THE MIDWEST. WITH 850MB
TEMPS DROPPING INTO THE 0 TO 5C RANGE...HIGH TEMPS WILL ONLY REACH
THE 50S ON BOTH SATURDAY AND SUNDAY...WITH OVERNIGHT LOWS DIPPING
INTO THE 30S. FURTHER OUT...MODEL DISCREPANCIES CONCERNING THE
EVOLUTION OF THE EASTERN CONUS TROUGH PERSIST...HOWEVER GENERAL
CONSENSUS POINTS TO A CONTINUED COOL NORTHWESTERLY FLOW ACROSS
ILLINOIS THROUGH AT LEAST EARLY NEXT WEEK.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
620 PM CDT THU APR 19 2012
...UPDATED AVIATION SECTION...
.SYNOPSIS...
ISSUED AT 1219 PM CDT THU APR 19 2012
UPPER AIR ANALYSIS AT 12Z THURSDAY INDICATED AN UPPER LEVEL JET
EXTENDED FROM WASHINGTON STATE SOUTHEAST INTO NORTHEASTERN
NEVADA. NEAR THE LEFT EXIT REGION OF THIS JET A -26 TO -28C 500MB
THERMAL TROUGH WAS LOCATED OVER MONTANA. 40 TO 50 METER HEIGHT
FALLS WERE ALSO OBSERVED AT RAPID CITY SOUTH DAKOTA AND DENVER
COLORADO WHILE ACROSS ALONG THE PACIFIC NORTHWEST 50 TO 70 METER
HEIGHT RISES WERE OCCURRING. IN THE CENTRAL PLAINS AT 12Z THURSDAY
BOTH THE 850MB AND 700MB LEVELS INDICATED AN AREA OF MOISTURE WAS
LOCATED NEAR A 850-700MB BAROCLINIC ZONE THAT EXTENDED FROM
NORTHEAST COLORADO INTO CENTRAL NEBRASKA. AT 13Z A SURFACE A COLD
FRONT EXTENDED FROM JUST WEST OF HAYS SOUTH ACROSS THE DODGE CITY
AREA INTO THE PANHANDLE OF TEXAS AND OKLAHOMA.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 152 PM CDT THU APR 19 2012
12Z NAM AND GFS REMAINS FAIRLY CONSISTENT WITH PREVIOUS RUNS IN
DEVELOPING CONVECTION LATE THIS AFTERNOON OVER THE HIGHER TERRAIN
OF COLORADO AS AN UPPER LEVEL JET APPROACHES THE ROCKIES. ANOTHER
AREA OF LATE DAY CONVECTION WILL ALSO BE POSSIBLE NEAR A COLD
FRONT WHICH WAS CROSSING SOUTH CENTRAL KANSAS AS OF 18Z. AT THIS
TIME IT APPEARS BASED ON THE HRRR AND NAM THIS FRONT WILL BE EAST
OF THE PRATT AND MEDICINE LODGE AREAS BY 00Z SO ANY PRECIPITATION
THAT WILL DEVELOP ALONG THIS BOUNDARY IS GOING TO OCCUR EAST OF
THESE LOCATIONS. FURTHER WEST BEHIND THIS FRONT THERE WILL STILL BE
SOME WEAK MID LEVEL INSTABILITY BASED ON MODEL SOUNDINGS EARLY
TONIGHT AND THE NAM EVEN GENERATES SOME VERY LIGHT QPF IN THIS AREA
OF INSTABILITY. AT THIS TIME GIVEN THE DRY AIR FORECAST BELOW THE
800MB LEVEL AM THINKING ONLY CLOUDS AND POSSIBLY VIRGA BUT WILL
CONTINUE TO MONITOR THIS AND ADJUST AS NEEDED FOR THE FIRST FEW
HOURS OF THE EVENING PERIOD.
CONVECTION DEVELOPING FURTHER WEST NEAR THE LEFT EXIT REGION OF
AN UPPER LEVEL JET APPEAR TO STAY WEST OF THE COLORADO BORDER
THROUGH 00Z. THESE STORMS ARE THEN FORECAST TO SPREAD EAST INTO
WESTERN KANSAS OVERNIGHT AS A 500MB THERMAL THROUGH WHICH WAS
LOCATED IN MONTANA AT 12Z THURSDAY MOVES SOUTHEAST INTO WESTERN
KANSAS. TRACK OF THIS UPPER TROUGH SUGGESTS PRECIPITATION CHANCES
WILL CONTINUE THROUGH EARLY FRIDAY AFTERNOON...ESPECIALLY EAST OF
HIGHWAY 283. THE PREVIOUS FORECAST HAS A DECENT HANDLE ON THE
EVOLUTION OF THIS PRECIPITATION SPREADING EAST ACROSS WESTERN
KANSAS LATER TONIGHT AND EARLY FRIDAY SO WILL STAY CLOSE TO THE
PREVIOUS TREND. DID HOWEVER POSTPONE THE ONSET OF THE
PRECIPITATION ACROSS THE FAR WEST UNTIL AFTER 00Z.
AS THE PRECIPITATION ENDS FROM WEST TO EAST THE SKIES ARE
EXPECTED TO CLEAR AS SUBSIDENCE DEVELOPS BEHIND THE UPPER LEVEL
TROUGH. BASED ON THE 18Z FRIDAY AND 00Z SATURDAY 925-950M
TEMPERATURES AND CLEARING SKIES WILL CONTINUE TO FAVOR HIGHS IN
THE MID 60S ACROSS MUCH OF WESTERN KANSAS. FURTHER EAST UPPER 50S
TO LOWER 60S APPEAR MORE REASONABLE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 245 PM CDT THU APR 19 2012
"WARM AND DRY" CAN DESCRIBE MOST OF THE EXTENDED PERIOD. WE WILL
SEE MODERATING TEMPERATURES OVER THE WEEKEND AS SURFACE LEE
TROUGHING STRENGTHENS. THE MAIN HEAT STORY BEGINS TUESDAY AND
CONTINUES THROUGH THE REST OF THE EXTENDED PERIOD AS 500 HPA
GEOPOTENTIAL HEIGHTS INCREASE IN RESPONSE TO AN AMPLIFIED RIDGE
BUILDING OVER THE ROCKIES. 850 HPA TEMPERATURES START AROUND 26-28
DEG C TUESDAY AND PEAK AROUND 28-30 DEG C BY THE END OF NEXT WEEK.
THIS SUPPORTS MIX DOWN TEMPERATURES WELL INTO THE 80S DEG F AND
MOST LIKELY SOME LOCATIONS WILL SEE >90 DEG F TEMPS. OVERNIGHT LOWS
THROUGH THE EXTENDED PERIOD WILL BE MILD AS MODERATE DEWPOINTS AND
SOUTHERLY WINDS CONTINUE. WILL KEEP SILENT POPS IN AS ANY UPPER LEVEL
FORCING REMAINS TO BE UNSEEN AND WEAK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 620 PM CDT THU APR 19 2012
MOSTLY CLOUDY SKIES ARE ANTICIPATED OVERNIGHT AS MID LEVEL
MOISTURE POOLS BEHIND A COLD FRONT DRAPED ACROSS OKLAHOMA AND THE
TEXAS PANHANDLE. MOSTLY CLOUDY SKIES AOA045 ARE FORECASTED BY
MIDNIGHT WITH A CHANCE OF LIGHT RAIN SHOWERS BEFORE SUNRISE
TOMORROW. WINDS WILL GENERALLY BE FROM THE NORTH AROUND 12 KNOTS
GUSTING TO OVER 15 KNOTS AT TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 44 61 39 76 / 50 20 0 0
GCK 43 62 40 77 / 60 20 0 0
EHA 45 66 41 79 / 50 10 0 0
LBL 45 65 40 78 / 40 20 0 0
HYS 41 60 38 76 / 30 20 0 0
P28 46 62 41 75 / 30 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...HOVORKA 42
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
1002 PM CDT THU APR 19 2012
.DISCUSSION...
SCATTERED CONVECTION HAS DEVELOPED ACROSS WRN OK/WRN N TX AND IS
JUST APPROACHING THE I-35 CORRIDOR AS OF 0230Z. BASED ON LATEST
RADAR TRENDS...TSTMS SHOULD STAY WEST OF THE CWA UNTIL AROUND 08Z.
THIS IS ALSO SUPPORTED BY THE LATEST RUNS OF THE NAM AND RUC WHICH
DELAY THE ARRIVAL OF TSTMS UNTIL AT LEAST 09Z-10Z. THEREFORE...REMOVED
POPS FROM THE FCST UNTIL AFTER 06Z AND MINOR SOME MINOR TWEAKS TO
REDUCE SKY COVER BASED ON LATEST IR SAT LOOPS.
OTHERWISE...REMAINDER OF FCST IS UNCHANGED.
UPDATED PRODUCTS HAVE BEEN SENT. /09/
&&
.AVIATION...
CLEAR SKIES WILL BE REPLACED WITH HIGH CLOUDS DURING THE NIGHT
WITH WINDS IN THE BOUNDARY LAYER AND LLJ LEVEL THAT WILL BE
RETURNING GULF MOISTURE...ALLOWING FOR THE SPREAD OF MVFR CEILINGS
INTO EAST AND NORTHEAST TEXAS...AND NORTHWEST AND NORTH CENTRAL
LOUISIANA AFTER 20/09 UTC TO 20/12 UTC. THIS SHOULD AFFECT THE
TERMINAL SITES OF KTYR...KGGG...KLFK...AND KSHV. A SURFACE LOW WILL
BE MOVING INTO PARTS OF EAST TEXAS NEAR 20/13 UTC WITH A COLD FRONT
PUSHING ACROSS NORTH TEXAS AND SOUTH OKLAHOMA AND NORTHWEST ARKANSAS
DURING THE EARLY TO MID MORNING HOURS FRIDAY. SHOWERS AND
THUNDERSTORMS WILL BE ISOLATED OUT AHEAD OF THE BOUNDARY WITH
WINDS SOUTH TO SOUTHWEST. AROUND THE SURFACE LOW FLIGHT CATEGORIES
MAY BECOME IFR CEILINGS AND VISIBILITIES. CONVECTION WILL AFFECT SE
OK/SW AR/EXTREME NE TX BETWEEN 20/10 UTC TO 20/14 UTC WITH REMAINING
TERMINALS BETWEEN 20/19 UTC TO 20/23 UTC. IN THE AFTERNOON THE FRONT
WILL CONTINUE TO MOVE TO THE SOUTHEAST ACROSS THE FOUR STATE REGION
PROVIDING A BAND OF SHOWERS AND THUNDERSTORMS...WITH CEILINGS AND
VISIBILITIES DETERIORATING IN AND NEAR THE CONVECTION. NORTHERLY
WINDS WILL RETURN AFTER THE FRONT PASSES WITH THE RAIN LINGERING
IN WAKE OF THE BOUNDARY DURING THE EVENING AND INTO EARLY SATURDAY
MORNING. FLIGHT CATEGORIES WILL BE RETURNING TO VFR BETWEEN 20/18
UTC TO 20/21 UTC SATURDAY FROM WEST TO EAST. WINDS WILL BE SOUTH 5
TO 10 KNOTS THROUGH 20/13 UTC FRIDAY...THEN BECOMING SOUTHWEST AHEAD
OF THE SURFACE LOW AND FRONTAL PASSAGE REMAINING FROM 5 TO 10 KNOTS
EXCEPT 10 TO 15 KNOTS AS THEY SHIFT TO THE NORTHWEST OVERNIGHT
FRIDAY INTO SATURDAY. PRESSURE GRADIENT SHOULD KEEP WINDS NORTH 12
TO 16 KNOTS THROUGH THE DAY SATURDAY. /06/
&&
.PREV DISCUSSION... /ISSUED 405 PM CDT THU APR 19 2012/
DISCUSSION...
MOSTLY SUNNY AND PUSHING TOWARD THE 80 DEGREE MARK FOR AN AVERAGE
OVER THE FOUR STATE AREA THIS AFTERNOON. OUR WINDS ARE SOUTHERLY
WITH SLOWLY INCREASING DEW POINTS...EVEN A FEW GUSTS EDGING IN
OVER THE WEST. MEANWHILE...THE COLD FRONT IS STILL BARRELING
THROUGH THE TX/OK PANHANDLES WITH COOL 40 DEGREE DEW POINTS
DROPPING SOUTHWARD ON GUSTY WINDS. THE WATER VAPOR SHOWS A
SHARPENING TROUGH OVER NM HOT ON THE HEELS OF THE SURFACE COLD
FRONT.
THE MODELS ARE ALL FASTER WITH THE COLD FRONT AND PRECIP THAN
YESTERDAY ANYWAY...BRINGING THE BOUNDARY INTO OUR CWA DURING PEAK
HEATING ON FRIDAY. SHOWERS AND THUNDERSTORMS WILL BE SLOW TO DEVELOP
TONIGHT AND COVERAGE WILL BE PICKING UP TOWARD DAYBREAK INTO
I-30. THE DAYTIME HEATING WILL BE LIMITED BY MORNING STRATUS SO
WIDE SPREAD SEVERE WEATHER IS NOT ANTICIPATED. HOWEVER...THE
EVOLUTION OF THUNDERSTORMS ON A FAST MOVING COLD FRONT AT THIS
TIME OF YEAR SHOULD NOT BE UNDERESTIMATED. EVEN BEHIND THE FRONT A
GOOD DEAL OF RAIN WILL LINGER WITH ENOUGH INSTABILITY ALOFT
PERHAPS TO CROP UP SOME HAIL...PER SPC DAY TWO.
THE BEST NEWS IS THAT THE SYSTEM LOOKS TO BE ON A QUICKER PACE FOR
THE IMPROVED WEEKEND FORECAST. ALTHOUGH LOW CLOUDS OVER COOLER AIR
BEHIND A FRONT CAN ALWAYS BE DISAPPOINTING...BUT AT LEAST THE RAIN
WILL BE CLEARING EARLIER THAN WAS EXPECTED ANYWAY. MAV/MEX BLENDED
WITH IN REASON...SOME NUMBERS LIKE SATURDAY MORNING LOOK TO COOL. /24/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 58 75 50 69 49 / 10 60 50 10 10
MLU 56 80 55 67 49 / 10 30 60 20 10
DEQ 55 68 44 68 43 / 30 60 40 10 0
TXK 57 73 48 68 49 / 20 60 50 10 10
ELD 56 77 50 67 46 / 10 60 60 10 10
TYR 61 71 47 71 49 / 20 60 40 10 10
GGG 60 72 49 70 48 / 20 60 50 10 10
LFK 60 78 51 71 50 / 10 60 60 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
09/06
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1052 AM EDT WED APR 18 2012
.SYNOPSIS...
SHOWERS MOVING ACROSS THE SOUTHEAST STATES WILL EXTEND TO THE
RIDGES TODAY BEFORE HIGH PRESSURE BUILDS IN AND KEEPS CONDITIONS
DRY UNTIL FRIDAY. A SLOW MOVING COLD FRONT WILL BRING THE CHANCE
FOR SHOWERS FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPPER LEVEL SHORTWAVE MOVING ACROSS THE SOUTHEAST STATES WILL
CONTINUE PROVIDING SHOWERS EXTENDING INTO SOUTHERN PART OF CWA
THROUGH TONIGHT. INCREASED POPS FOR SOUTHERN COUNTIES BASED ON
LATEST HRRR AND RADAR TRENDS. CLOUD COVER WILL REMAIN THE GREATEST
IN SOUTHERN AND EASTERN CWA...KEEPING TEMPERATURES SLIGHTLY COOLER
THAN WESTERN AND NORTHERN COUNTIES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
LOW PRESSURE OVER QUEBEC THURSDAY MORNING WILL MOVE TO THE
EAST...WITH A TRAILING COLD FRONT ACROSS THE GREAT LAKES. COLD FRONT
SHOULD REMAIN ACROSS THE EASTERN GREAT LAKES ON THURSDAY...KEEPING
DRY WEATHER LOCALLY. FRONT WILL MAKE VERY SLOW PROGRESS
FRIDAY...WITH SHOWERS FINALLY DRIFTING INLAND. 21Z SREF IS THE
OUTLIER FOR MOVING THE FRONT THROUGH FRIDAY NIGHT...AND WILL
CONTINUE TO GO WITH SLOWER GFS/ECMWF SOLUTIONS. RAIN SHOULD FINALLY
MOVE IN FOR SATURDAY. WITH SOUTHWESTERLY FLOW...TEMPERATURES WILL BE
ON THE INCREASE THURSDAY AND FRIDAY...RISING TO 10 AND THEN 15
DEGREES ABOVE NORMAL. FRONTAL TIMING WILL BE THE KEY TO HIGH
TEMPERATURES ON SATURDAY...AND FOR NOW HAVE DROPPED TEMPERATURES
BACK TO NEAR NORMAL LEVELS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
PRECIPITATION WILL TAPER TO SCATTERED COVERAGE AS COLD FRONT MOVES
EAST SATURDAY NIGHT. MODELS SHOW A CLOSED UPPER LOW FORMING AT
THE BOTTOM OF A SHARP TROUGH AND RIDING EAST ALONG THE GULF COAST
SATURDAY AND SUNDAY. LATEST MODEL RUNS STILL DIFFER ON THE TRACK
OF A SURFACE LOW MOVING ALONG THE EASTERN SEABOARD AND THE WESTERN
EXTENT OF PRECIPITATION MONDAY AND TUESDAY. FORECAST POPS ARE
CLOSE TO HPC NUMBERS WITH HIGH END CHANCE POPS SUNDAY TAPERING TO
AROUND 30 PERCENT ALONG THE RIDGES AND SLIGHT CHANCE FURTHER WEST
BY MONDAY MORNING.
TEMPERATURES ARE FORECAST TO COOL TO BETWEEN 5 AND 10 DEGREES BELOW
NORMAL BY EARLY NEXT WEEK.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
EXPECT VFR TO CONTINUE ACROSS THE UPPER OHIO VALLEY THROUGH
TONIGHT AS RAIN WITH A MID-LEVEL DISTURBANCE PASSES JUST SOUTHEAST OF
THE AREA. THERE IS A CHANCE OF A BRIEF VFR SHOWER AT KMGW, ALTHOUGH
CONFIDENCE IN NORTHERN PROGRESSION OF PRECIP IS TOO LOW TO MENTION
IN THE TAF AT THIS TIME. WINDS WILL BE FROM THE NORTHEAST AND EAST
AT 4-8 KTS.
OUTLOOK...THURSDAY THROUGH SUNDAY...
EXPECT VFR THURSDAY AND FRIDAY. RESTRICTIONS WILL BECOME LIKELY
FRIDAY NIGHT INTO SUNDAY DUE TO SHOWERS ASSOCIATED WITH THE SLOW
PASSAGE OF AN EASTBOUND LOW PRESSURE SYSTEM.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
746 AM EDT WED APR 18 2012
.SYNOPSIS...
CONDITIONS ARE EXPECTED TO BE DRY INTO FRIDAY...EXCEPT FOR THE
CHANCE OF LIGHT RAIN IN THE RIDGES TODAY. A WEEKEND COLD FRONT
SHOULD BRING THE NEXT CHANCE FOR WIDESPREAD RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
745AM UPDATE...UPDATED PROBABILITY OF PRECIPITATION AND WEATHER TYPE
GRIDS TO REFLECT CURRENT RADAR. PRECIPITATION TRACKING JUST A BIT
FARTHER NORTH THAN GUIDANCE. REMAINDER UNCHANGED.
PREVIOUS DISCUSSION...
ALL MODELS ARE IN GOOD AGREEMENT SHOWING THE PASSAGE OF AN UPPER
LEVEL SHORTWAVE MOVING ACROSS THE MID-ATLANTIC STATES TODAY AND
TONIGHT. SYNOPTIC/HI-RES MODELS ALSO SHOW SIMILAR DEPICTIONS OF
TIGHT PRECIPITATION GRADIENT FALLING JUST EAST OF THE FORECAST AREA.
HOWEVER...COMPARING MODEL FORECASTS AT 06Z TO RADAR SHOWS THAT ALL
MODELS EXCEPT FOR THE HRRR HAVE NOT TRENDED PRECIP FAR ENOUGH TO THE
NORTH AND WEST. THEREFORE...HAVE MOVED MORE IN THE DIRECTION OF THE
21Z SREF AND 03Z HRRR...BRINGING POPS FARTHER INTO
FAYETTE...MARION...AND MONONGALIA COUNTIES. LATER FORECASTS MAY NEED
TO BRING RAIN FARTHER TO THE NORTH AND WEST. CLOUD SHIELD WILL
EXTEND EVEN FARTHER TO THE NORTH AND WEST...WITH ALL LOCATIONS
EXPECTING PARTLY CLOUDY SKIES IN THE MORNING AND INCREASING SUN
OUTSIDE OF THE RIDGES IN THE AFTERNOON. RAIN COULD POTENTIALLY HOLD
ON INTO THE EVENING HOURS IN THE RIDGES...BUT WILL DRY OUT FOR THE
OVERNIGHT HOURS. TEMPERATURES SHOULD BE FAIRLY CLOSE TO YESTERDAYS
VALUES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
LOW PRESSURE OVER QUEBEC THURSDAY MORNING WILL MOVE TO THE
EAST...WITH A TRAILING COLD FRONT ACROSS THE GREAT LAKES. COLD FRONT
SHOULD REMAIN ACROSS THE EASTERN GREAT LAKES ON THURSDAY...KEEPING
DRY WEATHER LOCALLY. FRONT WILL MAKE VERY SLOW PROGRESS
FRIDAY...WITH SHOWERS FINALLY DRIFTING INLAND. 21Z SREF IS THE
OUTLIER FOR MOVING THE FRONT THROUGH FRIDAY NIGHT...AND WILL
CONTINUE TO GO WITH SLOWER GFS/ECMWF SOLUTIONS. RAIN SHOULD FINALLY
MOVE IN FOR SATURDAY. WITH SOUTHWESTERLY FLOW...TEMPERATURES WILL BE
ON THE INCREASE THURSDAY AND FRIDAY...RISING TO 10 AND THEN 15
DEGREES ABOVE NORMAL. FRONTAL TIMING WILL BE THE KEY TO HIGH
TEMPERATURES ON SATURDAY...AND FOR NOW HAVE DROPPED TEMPERATURES
BACK TO NEAR NORMAL LEVELS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
PRECIPITATION WILL TAPER TO SCATTERED COVERAGE AS COLD FRONT MOVES
EAST SATURDAY NIGHT. MODELS SHOW A CLOSED UPPER LOW FORMING AT
THE BOTTOM OF A SHARP TROUGH AND RIDING EAST ALONG THE GULF COAST
SATURDAY AND SUNDAY. LATEST MODEL RUNS STILL DIFFER ON THE TRACK
OF A SURFACE LOW MOVING ALONG THE EASTERN SEABOARD AND THE WESTERN
EXTENT OF PRECIPITATION MONDAY AND TUESDAY. FORECAST POPS ARE
CLOSE TO HPC NUMBERS WITH HIGH END CHANCE POPS SUNDAY TAPERING TO
AROUND 30 PERCENT ALONG THE RIDGES AND SLIGHT CHANCE FURTHER WEST
BY MONDAY MORNING.
TEMPERATURES ARE FORECAST TO COOL TO BETWEEN 5 AND 10 DEGREES BELOW
NORMAL BY EARLY NEXT WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
EXPECT VFR TO CONTINUE ACROSS THE UPPER OHIO VALLEY THROUGH
TONIGHT, WITH LITTLE MORE THAN BANDS OF ALTOCUMULUS. SURFACE WINDS
WILL BE FROM THE NORTHEAST AND EAST AT 4-8 KTS.
OUTLOOK...THURSDAY THROUGH SUNDAY...
EXPECT VFR THURSDAY AND FRIDAY. RESTRICTIONS WILL BECOME LIKELY
FRIDAY NIGHT INTO SUNDAY DUE TO SHOWERS ASSOCIATED WITH THE SLOW
PASSAGE OF AN EASTBOUND LOW PRESSURE SYSTEM.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
319 AM EDT WED APR 18 2012
.SYNOPSIS...
CONDITIONS ARE EXPECTED TO BE DRY INTO FRIDAY...EXCEPT FOR THE
CHANCE OF LIGHT RAIN IN THE RIDGES TODAY. A WEEKEND COLD FRONT
SHOULD BRING THE NEXT CHANCE FOR WIDESPREAD RAIN.
&&
.NEAR TERM /THROUGH TONIGHT/...
ALL MODELS ARE IN GOOD AGREEMENT SHOWING THE PASSAGE OF AN UPPER
LEVEL SHORTWAVE MOVING ACROSS THE MID-ATLANTIC STATES TODAY AND
TONIGHT. SYNOPTIC/HI-RES MODELS ALSO SHOW SIMILAR DEPICTIONS OF
TIGHT PRECIPITATION GRADIENT FALLING JUST EAST OF THE FORECAST AREA.
HOWEVER...COMPARING MODEL FORECASTS AT 06Z TO RADAR SHOWS THAT ALL
MODELS EXCEPT FOR THE HRRR HAVE NOT TRENDED PRECIP FAR ENOUGH TO THE
NORTH AND WEST. THEREFORE...HAVE MOVED MORE IN THE DIRECTION OF THE
21Z SREF AND 03Z HRRR...BRINGING POPS FARTHER INTO
FAYETTE...MARION...AND MONONGALIA COUNTIES. LATER FORECASTS MAY NEED
TO BRING RAIN FARTHER TO THE NORTH AND WEST. CLOUD SHIELD WILL
EXTEND EVEN FARTHER TO THE NORTH AND WEST...WITH ALL LOCATIONS
EXPECTING PARTLY CLOUDY SKIES IN THE MORNING AND INCREASING SUN
OUTSIDE OF THE RIDGES IN THE AFTERNOON. RAIN COULD POTENTIALLY HOLD
ON INTO THE EVENING HOURS IN THE RIDGES...BUT WILL DRY OUT FOR THE
OVERNIGHT HOURS. TEMPERATURES SHOULD BE FAIRLY CLOSE TO YESTERDAYS
VALUES.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
LOW PRESSURE OVER QUEBEC THURSDAY MORNING WILL MOVE TO THE
EAST...WITH A TRAILING COLD FRONT ACROSS THE GREAT LAKES. COLD FRONT
SHOULD REMAIN ACROSS THE EASTERN GREAT LAKES ON THURSDAY...KEEPING
DRY WEATHER LOCALLY. FRONT WILL MAKE VERY SLOW PROGRESS
FRIDAY...WITH SHOWERS FINALLY DRIFTING INLAND. 21Z SREF IS THE
OUTLIER FOR MOVING THE FRONT THROUGH FRIDAY NIGHT...AND WILL
CONTINUE TO GO WITH SLOWER GFS/ECMWF SOLUTIONS. RAIN SHOULD FINALLY
MOVE IN FOR SATURDAY. WITH SOUTHWESTERLY FLOW...TEMPERATURES WILL BE
ON THE INCREASE THURSDAY AND FRIDAY...RISING TO 10 AND THEN 15
DEGREES ABOVE NORMAL. FRONTAL TIMING WILL BE THE KEY TO HIGH
TEMPERATURES ON SATURDAY...AND FOR NOW HAVE DROPPED TEMPERATURES
BACK TO NEAR NORMAL LEVELS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
PRECIPITATION WILL TAPER TO SCATTERED COVERAGE AS COLD FRONT MOVES
EAST SATURDAY NIGHT. MODELS SHOW A CLOSED UPPER LOW FORMING AT
THE BOTTOM OF A SHARP TROUGH AND RIDING EAST ALONG THE GULF COAST
SATURDAY AND SUNDAY. LATEST MODEL RUNS STILL DIFFER ON THE TRACK
OF A SURFACE LOW MOVING ALONG THE EASTERN SEABOARD AND THE WESTERN
EXTENT OF PRECIPITATION MONDAY AND TUESDAY. FORECAST POPS ARE
CLOSE TO HPC NUMBERS WITH HIGH END CHANCE POPS SUNDAY TAPERING TO
AROUND 30 PERCENT ALONG THE RIDGES AND SLIGHT CHANCE FURTHER WEST
BY MONDAY MORNING.
TEMPERATURES ARE FORECAST TO COOL TO BETWEEN 5 AND 10 DEGREES BELOW
NORMAL BY EARLY NEXT WEEK.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
EXPECT VFR TO CONTINUE ACROSS THE UPPER OHIO VALLEY THROUGH
TONIGHT, WITH LITTLE MORE THAN BANDS OF ALTOCUMULUS. SURFACE WINDS
WILL BE FROM THE NORTHEAST AND EAST AT 4-8 KTS.
OUTLOOK...THURSDAY THROUGH SUNDAY...
EXPECT VFR THURSDAY AND FRIDAY. RESTRICTIONS WILL BECOME LIKELY
FRIDAY NIGHT INTO SUNDAY DUE TO SHOWERS ASSOCIATED WITH THE SLOW
PASSAGE OF AN EASTBOUND LOW PRESSURE SYSTEM.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1054 PM EDT THU APR 19 2012
.SYNOPSIS...
ISSUED AT 433 PM EDT THU APR 19 2012
A STORM SYSTEM ORGANIZING OVER THE PLAINS...WILL LIFT TOWARD THE
OHIO VALLEY TONIGHT...BEFORE EXITING EAST INTO LAKE ONTARIO FRIDAY.
RAIN WILL OVERSPREAD THE STATE THIS EVENING...IN ADVANCE OF THE
APPROACHING SYSTEM. THE RAIN WILL CHANGE TO SNOW ACROSS EAST UPPER
AND THE STRAITS REGION OVERNIGHT...AS COLDER AIR FILTERS INTO THE
NORTHERN GREAT LAKES. COLD AIR WILL CONTINUE TO PUSH ACROSS THE STATE
FRIDAY...GENERATING SNOW FOR MUCH OF NORTHERN MICHIGAN.
HIGH PRESSURE FROM THE UPPER MIDWEST AND CENTRAL CANADA...WILL BUILD
INTO THE GREAT LAKES FRIDAY NIGHT...ON THE BACKSIDE OF THE EXITING
OHIO VALLEY SYSTEM. HIGH PRESSURE WILL THEN LINGER OVER THE STATE
INTO THE BEGINNING OF THE UPCOMING WORK WEEK. THIS PATTERN WILL
GENERATE SOME SUN AND MILD TEMPERATURES THROUGH THE WEEKEND.
&&
.UPDATE...
ISSUED AT 1023 PM EDT THU APR 19 2012
WILL GO AHEAD AND ADD EMMET...CHEBOYGAN...PRESQUE ISLE COUNTIES TO
THE ADVISORY WITH THIS ISSUANCE BASED ON RECENT OBSERVATIONAL
TRENDS...AS WELL AS NEW 00Z NAM...AS WELL AS OUR IN HOUSE LOCAL
WRF AND HRRR. DUAL POL DATA CONFIRMS THAT THE MELTING LAYER IS AT
ABOUT 3-4KFT AT APX...AND HAS DIPPED DOWN BELOW 2KFT AT TIMES.
OBSERVATIONS FROM ACROSS LAKE MICHIGAN ARE SHOWING RAIN CHANGING
TO SNOW AT WAUSAU...WITH TEMPERATURES FALLING QUICKLY UNDER
DEVELOPING BANDED PRECIPITATION IN FGEN/DEFORMATION BULLSEYE IN
THE H85-H7 LEVEL.
HRRR/LOCAL WRF ARE VERY AGGRESSIVE SHOWIGN COOLING OVER THE TIP OF
THE MITT AFTER 9Z...WITH SNOW REACHING AS FAR SOUTH AS GAYLORD BY
DAYBREAK IN THESE SOLUTIONS. NEW 00Z NAM TRENDED HEAVILY IN THIS
DIRECTION...AND WHILE I THINK THE COOLING RATES ARE A LITTLE
OVERDONE...I WILL TREND THE FORECAST SLIGHTLY COOLER...AND A
LITTLE SNOWIER BEFORE DAYBREAK. GIVEN THAT CONFIDENCE IS NOW
INCREASING THAT A CHANGEOVER TO SNOW WILL OCCUR TOWARDS DAYBREAK
/WITH AMPLE PRECIPITATION LIKELY AFTER THIS POINT/ FEEL THAT THE
EXPANDED ADVISORY IS WARRANTED.
HAVE ALSO BROUGHT A DECREASE IN POPS /TO SCT SHRAS/ TO SOUTHERN
AREAS FOR A TIME TONIGHT AS BACK EDGE TO INITIAL WARM ADVECTION
SURGE PUSHES EAST...WITH A BREAK BEFORE THE FGEN-BAND SAGS SOUTH
AND EAST WELL AFTER MIDNIGHT.
UPDATE ISSUED AT 652 PM EDT THU APR 19 2012
PRIMARY UPDATE AT THIS TIME IS TO REFINE LEADING EDGE OF PRECIP
FIELD THAT IS NOW ADVANCING NORTHEAST INTO THE CWA. SURFACE LOW
NOW OVER SOUTHEASTERN IOWA WITH IMPRESSIVE WARM ADVECTION PLUME AS
BAND OF ONE INCH PWATS SURGE NORTH OVER TIGHTENING FRONTAL BOUNDARY.
OTHER FIELDS NEED VERY LITTLE IN THE WAY OF UPDATING.
DUAL POL PRODUCTS SUGGESTING A MELTING LEVEL AROUND 4KFT AGL
ATTM...SOMEWHAT BELOW NEAR TERM GUIDANCE. STILL SAFELY STARING AS
RAIN...BUT WILL BE WATCHING THESE TRENDS /AND UPCOMING 00Z APX
RAOB/ FOR MORE CLUES TO THE LLEVEL THERMAL FIELDS AS LLEVEL
AGEOSTROPHIC NORTHERLIES SLOWLY COOL THE BOUNDARY LAYER.
AM A LITTLE CONCERNED GIVEN PLACEMENT OF RUC H85-H7 FGEN SIGNATURE
/WHICH RIGHT NOW IS LINING UP BETTER WITH PRECIP PLACEMENT THAN FN
CONVERGENCE/ ALONG WITH RECENT HRRR TRENDS THAT SUGGEST THAT THE
SOUTHERN EDGE OF THE PRECIPITATION SHIELD MAY ADVANCE A BIT
FURTHER NORTH THAN CURRENTLY INDICATED...ESPECIALLY AFTER
MIDNIGHT. WILL NOT MAKE CHANGES TO THIS PORTION OF THE FORECAST
JUST YET...BUT THIS WOULD MEAN SOME REDUCED RAINFALL TOTALS SE OF
A CAD-APN LINE IF THE TRENDS HOLD.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 433 PM EDT
THU APR 19 2012
EARLY AFTERNOON SURFACE ANALYSIS SHOWS 1005MB SURFACE WAVE OVER
NORTHEAST KANSAS...WARM/STATIONARY FRONT EXTENDS EAST ACROSS THE
SOUTHERN HALF OF IOWA/FAR NORTHERN ILLINOIS AND UP INTO SOUTHERN
LOWER MICHIGAN. LOW LEVEL ANTICYCLONIC FLOW ACROSS NORTHERN
MICHIGAN KEEPING WINDS OUT OF THE NORTH AND KEEPING TEMPERATURES
COOLER...PERSISTENT DIURNALLY ENHANCED STRATOCUMULUS DECK ACROSS
EASTERN UPPER ALSO HELPING KEEP TEMPERATURES IN THE LOWER-MID 40S.
BAROCLINIC ZONE COMBINED WITH WELL DEFINED VORTICITY CENTER HEADED
TOWARD THE NEBRASKA/IOWA BORDER IS SPREADING RAIN SHOWERS
EAST-NORTHEAST ACROSS IOWA/SOUTHERN MINNESOTA/SOUTHERN WISCONSIN...
WITH AN AXIS OF 1+ INCH PRECIPITABLE WATER VALUES POOLED ALONG THE
FRONT.
KANSAS SURFACE LOW FORECAST TO TRACK EAST-NORTHEAST AND INTO FAR
SOUTHWEST LOWER MICHIGAN BY FRIDAY MORNING...WITH ASSOCIATED
EAST-WEST BAROCLINIC ZONE ALSO NUDGING NORTHWARD WITH A TIGHT
THERMAL GRADIENT SETTING UP ACROSS LOWER MICHIGAN. LOOKING LIKE A
GOOD SETUP FOR A MODERATE-HEAVY PRECIPITATION EVENT...AS WARM
ADVECTION NORTH OF FRONTAL ZONE COMBINES WITH STRONGLY SLOPED
FRONTOGENETIC RESPONSE AND RIGHT ENTRANCE REGION DYNAMICS FROM
DEVELOPING JET STREAK TO THE NORTH AND NORTHEAST OF LAKE SUPERIOR.
CURRENT EXPECTATION IS THAT HEAVIEST QPF WILL SET UP ACROSS FAR
NORTHWEST LOWER MICHIGAN AND THE STRAITS REGION BASED ON LOCATION OF
STRONGEST FORCING...WILL LIKELY BE A TIGHT GRADIENT TO THE NORTH
GIVEN MID LEVEL DEFORMATION AND LOWER LAYER SUBSIDENCE IN DESCENDING
BRANCH OF FRONTOGENETIC CIRCULATION. PRECIPITATION AMOUNTS IN
EXCESS OF AN INCH APPEAR POSSIBLE WITHIN A MBL-TVC-PLN AXIS (WILL
CARRY A HEAVY RAIN MENTION IN THESE AREAS). RAINFALL IS MAKING
STEADY PROGRESS ACROSS WISCONSIN...AND WILL SPREAD INTO THE FORECAST
AREA FROM THE SOUTHWEST THIS EVENING. MAIN PROBLEM IS GOING TO BE
PRECIPITATION TYPE...AS "COLDEST" AIR BUMPS UP AGAINST NORTHERN QPF
GRADIENT ACROSS EASTERN UPPER. TEMPERATURES IN THE MID 40S/DEW
POINTS IN THE MID 30S WILL ENSURE PRECIPITATION STARTS AS RAIN FROM
THE STRAITS NORTHWARD...AFTER MIDNIGHT SOME LOW LEVEL COLD ADVECTION
FROM THE NORTHEAST AND COOLING DUE TO MELTING/EVAPORATION FORECAST
TO GRADUALLY ERODE AWAY SURFACE BASED WARM LAYER. NOT EXPECTING
SURFACE TEMPERATURES TO FALL BELOW FREEZING...BUT WARM LAYER MAY
SHRINK ENOUGH TO ALLOW PRECIP TO TRANSITION TOWARD SNOW ACROSS
EASTERN UPPER AND POSSIBLY INTO THE TIP OF THE MITT COUNTIES AS
WELL. SNOW AMOUNTS OVERNIGHT WILL ALL DEPEND ON HOW QUICKLY THIS
PROCESS OCCURS (IF IT OCCURS AT ALL...WHICH IS ALSO A POSSIBILITY).
ASSUMING A LATER TRANSITION WENT WITH UP TO 2 INCHES NORTH OF THE
BRIDGE BY DAYBREAK.
SURFACE WAVE FORECAST TO HEAD EAST FROM SOUTHERN LOWER MICHIGAN AND
INTO THE LOWER GREAT LAKES DURING THE DAY FRIDAY. UPWARD FORCING
WILL STILL BE PRETTY STRONG ACROSS NORTHERN LOWER MICHIGAN TO START
THE DAY...SHIFTING EAST DURING THE MORNING WHICH WILL PULL HEAVIER
PRECIPITATION EASTWARD WITH IT. THERMAL FIELDS ACROSS EASTERN UPPER
AND FAR NORTHERN LOWER WILL STILL BE MARGINAL WITH REGARD TO PRECIP
TYPE...ESPECIALLY ALONG M-32 CORRIDOR WHERE GUIDANCE OFFERING UP
DIFFERING IDEAS. WILL PLAY WITH THE IDEA OF ALL SNOW ACROSS EASTERN
UPPER AND ALONG THE M-68 CORRIDOR...WITH A WINTRY MIX OF RAIN/
SLEET/SNOW POSSIBLE ALONG THE M-32 CORRIDOR. SEVERAL INCHES OF SNOW
POSSIBLE ACROSS THE TIP OF THE MITT AND FAR SOUTHEAST UPPER
MICHIGAN...CURRENT FORECAST WILL HAVE A BAND OF 3-5 INCHES OF SNOW
ALONG/NORTH OF M-68...HIGHLY SUBJECT TO CHANGE AND WILL BE DEPENDENT
ON HOW THERMAL PROFILE EVOLVES. SINCE IT APPEARS THAT EASTERN UPPER
MICHIGAN WILL BE MOST LIKELY TO SEE MORE PERSISTENT SNOWFALL OUT OF
THIS EVENT...WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR
CHIPPEWA/MACKINAC COUNTIES FOR LATE TONIGHT INTO FRIDAY MORNING. IF
COLDER AIR ARRIVES EARLY ENOUGH...HEADLINES WILL NEED TO BE EXPANDED
SOUTH INTO AT LEAST THE TIP OF THE MITT COUNTIES. BUT NOT CONFIDENT
ENOUGH ON TIMING YET...AND HAVE SOME TIME TO HOLD OFF SINCE GREATEST
THREAT FOR SNOWFALL ACROSS FAR NORTHERN LOWER WILL BE FRIDAY
MORNING.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 433 PM EDT
THU APR 19 2012
CURRENT QUASI-ZONAL FLOW PATTERN OVER THE LOWER 48 ABOUT SET TO GO
THROUGH DEEP AMPLIFICATION...COURTESY OF RAPID UPPER JET
INTENSIFICATION TODAY OVER ONTARIO...WITH SECONDARY STRONG UPPER JET
STREAK CUTTING INTO THE PACIFIC NORTHWEST. COMBO OF THESE WILL CARVE
OUT A DEEP EASTERN TROUGH THIS WEEKEND INTO EARLY NEXT WEEK...ITSELF
BOOKENDED BY AMPLIFYING INTERMOUNTAIN WEST AND DAVIS STRAITS
RIDGING. SAID CONFIGURATION PLACES NORTHERN MICHIGAN IN SOMEWHAT
PROLONGED PERIOD OF MAINLY DRY AND SEASONABLY COOL NORTH TO EAST
FLOW THOUGH EARLY NEXT WEEK. FORECAST CONCERNS CENTER ON TEMPERATURE
TRENDS AND PERIODIC LOW END RAIN CHANCES AS WEAK MOISTURE STARVED
WAVES ADVANCE THROUGH BACKSIDE OF EASTERN TROUGH.
FIRST THINGS FIRST...AND MAY STILL BE DEALING WITH A FEW RAIN/SNOW
SHOWERS EARLY FRIDAY EVENING AS LAST VESTIGES OF TONIGHTS/FRIDAY
SYSTEM (SEE SHORT TERM DISCUSSION) EXIT STAGE RIGHT. INFILTRATION OF
NORTH FLOW DEEP LAYER DRYING AND SURFACE HIGH PRESSURE SHOULD BRING
A QUICK END TO ANY PRECIP...LEAVING OVERNIGHT FRIDAY RIGHT THROUGH
SATURDAY NIGHT DRY WITH GRADUALLY DECREASING CLOUD COVER. WHILE
INCREASING AMOUNTS OF SUNSHINE SATURDAY WILL PARTIALLY OFFSET
MAINTENANCE OF COOL NORTH WINDS...CLEAR SKIES AND QUICK DECOUPLING
OFF LOW LEVEL WINDS WILL ALLOW TEMPERATURES TO DROP RAPIDLY SATURDAY
EVENING. LAST FEW WEEKS HAVE SEEN PLENTY OF SIMILAR SCENARIOS...AND
EACH HAVE RESULTED IN COLDER READINGS THAN GUIDANCE INITIALLY
ANTICIPATED. EXPECT THIS TO BE THE CASE ONCE AGAIN...AND HAVE GONE
AHEAD A CUT LOWS BY SEVERAL DEGREES...WITH MOST INLAND AREAS DOWN
INTO THE 20S BY EARLY SUNDAY MORNING (IF CURRENT TRENDS CONTINUE...
COULD EVEN SEE THE NEED TO LOWER TEMPERATURES A FEW MORE DEGREES IN
THE TYPICAL ICE BOX LOCATIONS).
SOME UNCERTAINTY FOR THE REMAINDER OF THE WEEKEND INTO THE MIDDLE
PORTIONS OF NEXT WEEK...MAINLY CENTERING ON LIGHT PRECIP POTENTIAL
SUNDAY WITH MOISTURE STARVED NORTHERN STREAM WAVE...AND WITH
ADDITIONAL RAIN CHANCES TUESDAY AND WEDNESDAY. AS FOR THE
FORMER...POSITION OF AFOREMENTIONED LARGE SCALE FEATURES SUGGEST
"BEST" DYNAMICS AND WAA FORCED ASCENT REMAINING TO OUR WEST ON
SUNDAY. DRY NORTHEAST LOW LEVEL FLOW ALSO SUGGESTS DRY WEATHER
CONTINUING THROUGH SUNDAY. MAINTENANCE OF NEAR STATIONARY SURFACE
HIGH STILL SUPPORTS A DRY BEGINNING TO NEXT WORK WEEK UNDER MOSTLY
CLEAR TO PARTLY CLOUDY SKIES. TYPICAL SPRINGTIME AIRMASS
MODIFICATION RESULTS IN SOME SLOW WARMING...WITH HIGHS MOSTLY IN THE
LOWER 50S BY MONDAY (A TOUCH COOLER NEAR THE BIG LAKES AND ACROSS
EASTERN UPPER). MUCH UNCERTAINTY REMAINS WITH THE MID WEEK RAIN
POTENTIAL...WITH LATEST (AND RATHER ROCK STEADY) ECMWF SHOWING MUCH
MORE AMPLIFIED AND SLOWER TO LEAVE EASTERN LAKES/EASTERN US TROUGH
THAN OTHER GUIDANCE. ECMWF SOLUTION WOULD EVEN SUGGEST SOME ATLANTIC
MOISTURE PINWHEELING BACK WEST...BRINGING AT LEAST THE THREAT OF
SOME RAINS TO OUR EASTERN AREAS TUESDAY AND TUESDAY NIGHT. THIS DOES
SEEM A TOUCH EXTREME...ALTHOUGH FEEL ITS DEPICTION OF A MORE
AGGRESSIVE EASTERN TROUGH IS VERY PLAUSIBLE. OTHER PROGS...
ESPECIALLY THE SOMEWHAT MORE PROGRESSIVE GFS...WOULD SUGGEST A MID
WEEK SHOWER THREAT VIA ADDITIONAL NORTHERN STREAM ENERGY DROPPING ON
BACKSIDE OF SLOWLY DEPARTING EAST CANADA TROUGH AXIS. CONFIDENCE ON
HOW THIS WILL PLAY OUT REMAINS EXCEPTIONALLY LOW...AND WILL SIMPLY
RIDE WITH A MODEL BLEND APPROACH...FEATURING LOW END RAIN CHANCES
TUESDAY NIGHT INTO WEDNESDAY. TEMPERATURES WILL ALSO BE HIGHLY
DEPENDENT ON HOW THE ABOVE UNFOLDS...WITH SOME POTENTIAL FOR COOL
NORTHERLY FLOW TO CONTINUE. WILL SHOW A SLOW WARMING TREND...BUT
WOULD NOT BE SURPRISED IF THIS...AND RAIN POTENTIAL...SEES
SIGNIFICANT CHANGES IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 143 PM EDT THU APR 19 2012
MID CLOUDS THICKEN LATER THIS AFTERNOON...WITH RAIN MOVING IN FROM
THE SOUTHWEST THIS EVENING WITH IFR CEILINGS EXPECTED TO DEVELOP.
MAY SEE IFR VISIBILITIES IN SNOWFALL AT PLN LATE. LOW LEVEL WIND
SHEAR ALSO A CONCERN AT LEAST AT TVC/MBL TONIGHT.
&&
.MARINE...
ISSUED AT 433 PM EDT THU APR 19 2012
INCREASINGLY GUSTY NORTHEAST WINDS NORTH OF PASSING SOUTHERN LAKES
LOW PRESSURE WILL RESULT IN SCA/S ACROSS MOST NEARSHORE WATERS
BORDERING NORTHERN LOWER MICHIGAN TONIGHT INTO FRIDAY AFTERNOON.
STRONGEST WINDS EXPECTED OVER NORTHERN LAKE HURON LATE TONIGHT INTO
FRIDAY...WITH GALE FORCE WIND GUSTS EXPECTED FROM NEAR THE STRAITS
DOWN TO STURGEON POINT. CONDITIONS WILL IMPROVE FRIDAY NIGHT INTO
THE WEEKEND AS HIGH PRESSURE BUILDS OVERHEAD.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY FROM 2 AM TO NOON EDT FRIDAY FOR MIZ008-
015>018.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT FRIDAY FOR LHZ345-346-349.
GALE WARNING FROM 5 AM TO 5 PM EDT FRIDAY FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT FRIDAY FOR LMZ323-341-342-
344>346.
LS...NONE.
&&
$$
UPDATE...JA
SYNOPSIS...SR
SHORT TERM...JB
LONG TERM...MB
MARINE...MB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
631 PM CDT THU APR 19 2012
.AVIATION... /00Z TAF ISSUANCE/
THE EXTENSIVE RAIN AREA FROM SOUTH CENTRAL MN INTO WEST CENTRAL WI
WILL BE EXITING TO THE EAST THIS EVENING AS LOW PRESSURE OVER IA
MOVES INTO IL. KEAU IS THE SITE WITH THE GREATEST IMPACT FOR MVFR
CEILINGS AND VISIBILITY THROUGH ABOUT 04Z. KRWF...KMSP AND KRNH
WILL SEE A FEW SPRINKLES OR LIGHT RAIN FOR ABOUT AN HOUR INTO THE
NEW TAF WITH VFR CEILINGS LIFTING THEREAFTER. KAXN AND KSTC WILL
SEE MAINLY HIGH LEVEL CI/CS ALTHOUGH SOME SCT-BKN050 MAY COME IN
FROM THE NORTHWEST LATER IN THE NIGHT. THERE WILL ALSO BE SOME
GUSTINESS TO THE NORTHEAST WIND THIS EVENING FOR A FEW HOURS.
NOTHING EXTREME BUT PERHAPS A FEW 16 TO 18 KNOT GUSTS NOT OUT OF
THE QUESTION. HIGH PRESSURE WILL BUILD IN FROM THE NORTHWEST ON
FRIDAY. THERE WILL BE A LITTLE BIT OF A GRADIENT DEVELOP BETWEEN
KMSP AND KEAU WITH 10-12 KNOT WINDS LIKELY ALONG WITH GUSTS TO 18
OR 20 KNOTS FROM MID MORNING AND INTO THE AFTERNOON HOURS. THERE
WILL ALSO BE SCT-BKN040-050 DEVELOP BETWEEN THE AFOREMENTIONED
SITES AS WELL.
KMSP...VFR CONDITIONS WILL PREVAIL OVERNIGHT AND FRIDAY. MAIN RAIN
AREA WILL BE JUST EAST AND SOUTH OF THE AIRFIELD FOR A FEW HOURS
THIS EVENING. THERE WILL BE A LITTLE GUSTINESS TO THE NORTHEAST
WIND THIS EVENING AS WELL. WINDS ON FRIDAY WILL BE MORE NORTH TO
NORTHWEST WITH GUSTS UP TO 20 KNOTS.
/OUTLOOK/...
SATURDAY...MVFR CIGS/VSBYS POSSIBLE WITH AS SHOWERS MOVE THROUGH.
SOUTH WINDS AT 15G25KTS...BECOMING NORTHWEST AT 15G20KT.
SUNDAY...VFR WITH NORTHWEST WINDS 15G25KT.
&&
.DISCUSSION... /ISSUED 219 PM CDT THU APR 19 2012/
PRIMARY WEATHER FEATURES OF CONCERN ARE THE SHORTWAVE AND
ASSOCIATED SURFACE LOW CURRENTLY MOVING BY TO OUR SOUTH... AND
ANOTHER SHORTWAVE WHICH WILL BE EMBEDDED IN NORTHWEST UPPER FLOW
THAT WILL MOVE THROUGH THE REGION ON SATURDAY. OVERALL... THE
LARGE SCALE PATTERN WILL EVOLVE FROM ITS FAIRLY ZONAL FLOW AT THE
MOMENT TO A MUCH MORE AMPLIFIED PATTERN AS WE WORK THROUGH THE
UPCOMING WEEK. THE NUMERICAL GUIDANCE IS IN GOOD AGREEMENT ON THE
INITIAL AMPLIFICATION OF THE UPPER FLOW... BUT DIVERGES QUITE A
BIT IN HOW THINGS WILL THEN EVOLVE DURING THE MIDDLE PART OF NEXT
WEEK. GENERALLY FOLLOWED A NAM/GFS BLEND THROUGH THE NEXT FEW
DAYS... THEN STEADILY WORKED WITH MORE OF AN ECMWF/GFS BLEND
BEYOND THAT WITH A BIT MORE WEIGHT ON THE ECMWF BY THE MIDDLE OF
NEXT WEEK. OVERALL... CONFIDENCE IS FAIRLY LOW IN THE DETAILS OF
THE TUESDAY THROUGH THURSDAY TIME PERIOD NEXT WEEK... SINCE MUCH
WILL DEPEND ON IF/WHEN THE RIDGE WILL BREAK DOWN. THE ECMWF
MAINTAINS THE RIDGE MUCH MORE THAN THE GFS... WHICH PUSHES AN
UPPER LOW SOUTH TOWARD THE REGION FROM CENTRAL CANADA.
SURFACE LOW CURRENTLY OVER FAR NORTHEAST KANSAS WILL CONTINUE TO
PUSH EAST-NORTHEAST THIS EVENING AS THE UPPER SHORTWAVE WORKS INTO
THE MID-MISSISSIPPI VALLEY. THE BEST ISENTROPIC LIFT AND MID-LEVEL
FRONTOGENESIS WILL BE ACROSS THE SOUTHERN PART OF OUR CWFA AND
INTO NORTHERN IOWA AND SOUTHWEST WISCONSIN. DECENT PCPN TOTALS CAN
BE EXPECTED SOUTH OF A LINE FROM MANKATO TO EAU CLAIRE AS THE
SYSTEM PUSHES THROUGH THIS AFTERNOON AND EVENING. THE BACK EDGE OF
THE PCPN MAY MIX WITH AND/OR CHANGE TO SOME SNOW THIS EVENING AS
COLDER AIR WORKS IN BEHIND THE UPPER WAVE. FORECAST SOUNDINGS FROM
THE NAM... GFS... AND RUC SUGGEST ONLY A BRIEF WINDOW OF SNOW
POTENTIAL ACROSS OUR AREA... MAINLY OVER PARTS OF WEST CENTRAL
WISCONSIN. BETTER ACCUMULATION POTENTIAL EXISTS EAST AND SOUTHEAST
OF OUR AREA... WHERE THERE LOOKS TO BE A LONGER DURATION OF A SUB-
FREEZING PROFILE... DEEP MOISTURE... AND LIFT. A WEAK RIDGE OF
HIGH PRESSURE WILL WORK ACROSS THE REGION LATE TONIGHT THROUGH
FRIDAY... WITH DRY WEATHER EXPECTED. THE RIDGE WILL STILL BE IN
PLACE ACROSS THE EASTERN FORECAST AREA FRIDAY NIGHT... WHICH COULD
LEAD TO SOME FROST/FREEZE ISSUES. INCLUDED A MENTION OF PATCHY
FROST IN THOSE AREAS FOR NOW TO ACCOUNT FOR THAT POSSIBILITY.
RETURN FLOW AND WARM ADVECTION WILL START TO ENCROACH ON THE
WESTERN PORTION OF THE AREA FRIDAY NIGHT... SO INCLUDED A CHANCE
OF SHRA OUT THERE FOR THE OVERNIGHT HOURS. THAT CHANCE FOR PCPN
THEN MIGRATES EASTWARD ACROSS THE AREA ON SATURDAY AS THE ZONE OF
ISENTROPIC LIFT WORKS ACROSS THE CWFA WITH AN EMBEDDED SHORTWAVE
IN NORTHWEST FLOW DROPPING THROUGH AT THE SAME TIME. THE MOST
PERSISTENT AND SUBSTANTIAL PCPN LOOKS LIKE IT SHOULD FOCUS MAINLY
TO OUR NORTH... BUT WOULD EXPECT MOST LOCATIONS TO SEE AT LEAST A
BRIEF WINDOW OF SOME PCPN ON SATURDAY INTO SATURDAY NIGHT. PCPN
CHANCES MAY LINGER ACROSS THE EAST ON SUNDAY ON THE BACKSIDE OF
THE UPPER TROUGH BEFORE MORE PRONOUNCED UPPER AND SURFACE RIDGING
ARE ABLE TO WORK INTO THE AREA.
FOR THE MONDAY THROUGH THURSDAY PERIOD... CONFIDENCE IS QUITE LOW
IN THE FORECAST DETAILS AS ELUDED TO EARLIER. TRIED TO SIDE A BIT
MORE WITH THE ECMWF... ALTHOUGH IT SHOULD BE NOTED THAT ITS 12Z
SOLUTION DID TREND SLIGHTLY TOWARD THE GFS IN THE IDEA OF
SQUASHING THE EAST SIDE OF THE UPPER RIDGE A BIT BY WEDNESDAY-
THURSDAY. GIVEN THE UNCERTAINTY AND SPREAD IN SOLUTIONS... WENT
WITH A BLENDED APPROACH WHICH RESULTS IN A LONGER PERIOD OF CHANCE
POPS THAN WHAT WILL LIKELY OCCUR. HOPEFULLY SUBSEQUENT FORECASTS
WILL BE ABLE TO REFINE THE MOST LIKELY LOCATIONS AND TIME PERIODS
FOR PCPN DURING THE PERIOD.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
RAH/TRH
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
640 PM CDT THU APR 19 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Have made adjustments to timing/areal coverage of evening/overnight
convection based on latest short range convective models and radar
trends. Minimal severe threat this evening. Have updated/adjusted
HWO. SPC meso page still shows decent amount of CIN while surface-
based CAPE in 250-500 range are pretty meager while 0-6km bulk shear
is below marginal values along the frontal boundary. Scattered
elevated showers forming over north central MO should build back to
the southwest with time and become more organized as the region of
elevated lift shifts east.
MJ
&&
.PREV DISCUSSION...
/419 PM CDT Thu Apr 19 2012/
Short Range (Tonight through Saturday)...
Satellite imagery from this afternoon shows the nation under the
influence of a progressive pattern, though some buckling of the
flow is apparent as a trough is seen exiting the Rocky Mountains.
Closer to home, a small shortwave ejected into the Plains ahead of
the primary trough exiting the mountainous west, and helped focus
the morning low level jet across northeast Kansas and northwest
Missouri, which resulted in some morning thunderstorms. Those storms
have since dissipated, leaving our attention focused back to our
west, where a cold front is advancing east across Kansas tied to the
leading shortwave.
Currently the front is located along a line from the tip of
northwest Missouri to Wichita, with a fair amount of cumulus cloud
cover bubbling up ahead of the front. Early afternoon soundings show
little in the way of available CAPE across our section of eastern
Kansas and Missouri, as RUC based analysis indicates there is only
about 500 J/KG of SBCAPE, and given the dry layer at the 700mb level
noted off an early afternoon sounding at KMCI, there was no ability
for the model to evaluate MLCAPE. The lack of instability looks to be
from both the cloud cover in advance of the front, and due to lower
than expected dew points, which have struggled to clime beyond the
low 50s. However, with the front advancing across Kansas, frontogenic
forcing is still expected to use what little CAPE is available late
this afternoon/early this evening to generate some scattered storms
in eastern Kansas. The storms should move northeast, but the line
will struggle to fill in unless more quality moisture can quickly
advect ahead of the front. Shear parameters for this evening are
more than sufficient to generate concerns for severe weather, but
given the lack of instability, and the way surface winds veer off as
the front moves through, and it is looking increasingly difficult for
us to realize any storms that could support much more than marginal
severe weather, which would be limited to large hail and damaging
straight line winds. Heavy rain may occur with some of these storms,
but at this time the lack of quality moisture and the progressive
nature of the front should preclude any widespread flooding threat.
With the continued consensus of the various short range operational
and ensemble models, have persisted in quickly moving the storms to
the east, leaving most of the forecast area dry after 12Z Friday.
Being behind the front Friday will allow for something we have not
seen a whole lot of in the past several months, cold air advection.
The breezy north wind behind the front will actually keep afternoon
highs below normal Friday. However, this cool trend will quickly
fade as southwest winds return for Saturday bringing highs in the 60s
back.
Cutter
Medium Range (Sunday through Thursday)...
No major changes planned to going medium range forecast. Upper
ridge axis forecast to strengthen over western US during early part
of next week while area of surface high pressure builds into
forecast area. By mid-week the upper feature shifts into the
central US. This combined with increasing southerly flow as surface
high moves to the east should provide for a gradual warm up.
Appears that temperatures could approach the 80 degree mark by
Wednesday and then again on Thursday. ECMWF, GFS, and GEM models
hinting at weak mid-level shortwave topping ridge in upper
Mississippi Valley in the Wednesday/Thursday time frame. Not out of
the realm of possibility to see some scattered precipitation over
northern Missouri with this feature. However there are enough
inconsistencies in the timing and geographic placement of the QPF
that dry forecast still appears to be the best way to go at this
time.
MJM
&&
.AVIATION...
For the 00Z TAFs...Surface cold front now passing through the KC
terminals. Scattered showers forming over north central MO should
build back to the southwest with isolated thunderstorms possible.
Believe any thunder threat will be southeast of KMCI so only KMKC
has it mentioned as a VC modifier. KSTJ may only see a passing brief
shower. Increasing northwesterly winds will spread into all 3
terminals this evening. Will start out with VFR cigs but large area
of MVFR cigs over NE will spread south into all 3 terminals tonight.
A few pockets of IFR cigs also noted and will amend if cigs
deteriorate overnight.
Cigs will improve to VFR by late morning with breezy northerly
winds.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
1127 AM MDT WED APR 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
AVIATION DISCUSSION UPDATED.
UPDATED THE FORECAST TO INCREASE POPS ACROSS THE WESTERN ZONES FOR
THIS MORNING AND TO LOWER THE OVER ALL HIGH TEMPERATURES. MADE A
FEW CALLS TO SPOTTERS AND COULD ONLY FIND VERY LIGHT RAIN TO
SPRINKLES. RAISED THE POPS UP TO AROUND 80 TO 90 PERCENT FOR THIS
MORNING AND LEFT IT AROUND 50 PERCENT FOR THIS AFTERNOON. THE HIGH
POPS FOR THIS MORNING ARE BASICALLY SAYING A VERY HIGH CHANCE OF
SPRINKLES TO MAYBE A FEW HUNDREDTHS OF AN INCH IF YOU ARE LUCKY.
SINCE WE HAVE THICKER CLOUD COVER AND THE ONSET OF PRECIPITATION
DECIDED TO LOWER THE TEMPERATURES THIS MORNING BY ALMOST 10
DEGREES ACROSS THE NORTHERN ZONES. CURRENT READING ARE STILL IN
THE UPPER 30S TO LOWER 40S ACROSS EASTERN MONTANA. EXPECT HIGHS TO
RANGE FROM THE MID 40S NORTH TO THE MID 50S ACROSS THE YELLOWSTONE
VALLEY. REST OF THE SHORT TERM FORECAST LOOKS GOOD. RSMITH
PREVIOUS DISCUSSION...THE SHORT TERM FORECAST IS A HARD ONE
TODAY FOR NORTHEAST MONTANA... MANY VARIABLES PLAYING INTO THE
FORECAST EQUATION FOR THE NEXT 48 HOURS.
FOR THE FIRST 12 HOUR TOOK THE HRRR FOR THE POPS/QPF FORECAST. IT
HAS PREFORMED VERY WELL THIS SPRING SEASON. PLUS THE GFS/NAM AGAIN
ARE BRINGING HIGH QPF VALUES TO NORTHEAST MONTANA. THE MODELS HAVE
A POOR TRACK RECORD IN THE PAST MONTH WITH FORECASTING QPF OVER
NORTHEAST MONTANA WITH A TREMENDOUS WET BIAS. MODEL SOUNDINGS SHOW
AT THE GGW POINT ...ALONG WITH BUFR SOUNDINGS... A SLOW MOISTENING
OF THE DRY LOW LEVELS THROUGH THE AFTERNOON HOURS. SPLIT THE
WEATHER GRIDS FOR THE FIRST 12 HOURS INTO 3 HOUR BLOCKS. DID THIS
TO SHOW THE STUBBORNLY SLOW PROGRESS OF MEASURABLE PRECIPITATION
ACROSS THE REGION. DO EXPECT LOTS OF VIRGA AND GUSTY WINDS THIS
AFTERNOON AS THE ATMOSPHERE MOISTENS UP. DECIDED TO FLY THE LAKE
WIND ADVISORY WITH THE MARGINAL 15 TO 25 MPH WINDS DUE TO THE GUST
FACTOR THAT COULD SURPRISE IN EXPERIENCED BOATERS EARLY IN THE
SEASON.
TONIGHT WENT WITH HIGH POP LOW QPF/LITTLE OR CHANCE OF WETTING
RAIN SOLUTION. CONFIDENCE IS MODERATE... MODELS ALL ARE GOING FOR
A WETTING RAIN ACROSS MOST OF NORTHEAST MONTANA. HOWEVER THE MODEL
PERFORMANCE ON RAINFALL HAS BEEN POOR AND OVER FORECASTING
RAINFALL.
ON THURSDAY AS THE WINDS SWITCH TO THE WEST ACROSS THE AREA CLOUD
BASES WILL RISE AND AGAIN THE BOUNDARY LAYER SHOULD DRY OUT
KEEPING MEASURABLE PRECIPITATION VALUES LOW. THE ONE ISSUE THAT
COULD INCREASE POPS THURSDAY AFTERNOON IS VERY STEEP LAPSE RATES
WHICH COULD SPARK A THUNDERSTORM AND CREATE SMALL AREAS OF HIGHER
RAINFALL.
THURSDAY NIGHT THE DAKOTA LOW WILL CONTINUE TO DRIFT EAST KEEPING
MOST AREAS DRY. ON FRIDAY A LOW MOVES OFF THE ALBERTA ROCKIES AND
SLIDES ACROSS SASKATCHEWAN INTO NORTH DAKOTA IN THE NORTHWEST FLOW
AHEAD OF THE BUILDING RIDGE. THIS MIGHT BRING ANOTHER VERY SLIGHT
CHANCE OF WETTING RAINS WITH STRONGER SHOWERS ACROSS THE NORTHERN
TIER OF ZONES. OTHERWISE MORE DUST SETTLING SHOWERS WITH LITTLE
RAIN RELIEF EXPECTED. PROTON
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE LAST IN A SERIES OF SEVERAL SHORTWAVE DISTURBANCES FROM THE W
MOVES OUT OF THE AREA FRI NIGHT. THEN A BUILDING UPPER RIDGE FROM
THE S OVER THE WEEKEND BRINGS SUNNY AND WARMER WEATHER. THE RIDGE
BECOMES QUITE STRONG WITH 850 MB TEMPS TO AS HIGH AS 18-24C
MONDAY. THICKNESSES VALUES REACH 570 DM. THIS SHOULD DRIVE NE MT
HIGHS INTO THE UPPER 70S TO MID 80S...WHICH WILL APPROACH RECORD
HIGHS FOR THE DATE AT SOME LOCATIONS.
MODELS AGREE WITH A MOSTLY DRY...BUT FAIRLY STRONG COLD FRONT FROM THE
WNW MOVING ACROSS THE AREA TUE...WHICH WILL START A COOLING TREND.
THE ASSOCIATED UPPER TROUGH LAGS BEHIND...AND MODELS HAVE VARIED
ON TIMING...INTENSITY...AND MOVEMENT WITH THIS. ECMWF HAS BEEN
TOO QUICK TO BREAK DOWN THE RIDGE. MEANWHILE CMC GEM DEFLECTS BOTH
COLD FRONT AND TROUGH TO OUR N AND KEEPS THE RIDGE OVER OUR AREA...WHICH
DOES APPEAR POSSIBLE. GFS ENSEMBLES INDICATE THAT ANY OF THESE AND
OTHER SOLUTIONS ARE POSSIBLE TOO...SO LOW CONFIDENCE AT THE END OF
THE PERIOD. PREFER THE 00Z OPERATIONAL GFS THOUGH WHICH IS MORE
OF A MIDDLE GROUND SOLUTION...AND DOES BRING AT LEAST A SLIGHT
CHANCE OF SHOWERS BY WED. SIMONSEN
&&
.AVIATION...
THIS STORM SYSTEM ACROSS NORTHEAST MONTANA WILL BE SLOW- MOVING
THROUGH THURSDAY WITH RAIN SHOWERS IN THE AFTERNOON AND A STEADY
LIGHT RAIN OVERNIGHT. EXPECT SOME INTERMITTENT MVFR CEILINGS TO
IMPACT KGGW AND KOLF. IFR TO LIFR CEILINGS ARE MORE LIKELY FOR
KSDY AND KGDV TOWARD THE END OF THIS TAF CYCLE. EXPECT OCCASIONAL
TAF AMENDMENTS THURSDAY MORNING. A LIGHT TO BARELY BREEZY EAST
WIND WILL BE OF NO CONSEQUENCE. BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR FORT PECK
LAKE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
940 AM MDT WED APR 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
UPDATED THE FORECAST TO INCREASE POPS ACROSS THE WESTERN ZONES FOR
THIS MORNING AND TO LOWER THE OVER ALL HIGH TEMPERATURES. MADE A
FEW CALLS TO SPOTTERS AND COULD ONLY FIND VERY LIGHT RAIN TO
SPRINKLES. RAISED THE POPS UP TO AROUND 80 TO 90 PERCENT FOR THIS
MORNING AND LEFT IT AROUND 50 PERCENT FOR THIS AFTERNOON. THE HIGH
POPS FOR THIS MORNING ARE BASICALLY SAYING A VERY HIGH CHANCE OF
SPRINKLES TO MAYBE A FEW HUNDREDTHS OF AN INCH IF YOU ARE LUCKY.
SINCE WE HAVE THICKER CLOUD COVER AND THE ONSET OF PRECIPITATION
DECIDED TO LOWER THE TEMPERATURES THIS MORNING BY ALMOST 10
DEGREES ACROSS THE NORTHERN ZONES. CURRENT READING ARE STILL IN
THE UPPER 30S TO LOWER 40S ACROSS EASTERN MONTANA. EXPECT HIGHS TO
RANGE FROM THE MID 40S NORTH TO THE MID 50S ACROSS THE YELLOWSTONE
VALLEY. REST OF THE SHORT TERM FORECAST LOOKS GOOD. RSMITH
PREVIOUS DISCUSSION...THE SHORT TERM FORECAST IS A HARD ONE
TODAY FOR NORTHEAST MONTANA... MANY VARIABLES PLAYING INTO THE
FORECAST EQUATION FOR THE NEXT 48 HOURS.
FOR THE FIRST 12 HOUR TOOK THE HRRR FOR THE POPS/QPF FORECAST. IT
HAS PREFORMED VERY WELL THIS SPRING SEASON. PLUS THE GFS/NAM AGAIN
ARE BRINGING HIGH QPF VALUES TO NORTHEAST MONTANA. THE MODELS HAVE
A POOR TRACK RECORD IN THE PAST MONTH WITH FORECASTING QPF OVER
NORTHEAST MONTANA WITH A TREMENDOUS WET BIAS. MODEL SOUNDINGS SHOW
AT THE GGW POINT ...ALONG WITH BUFR SOUNDINGS... A SLOW MOISTENING
OF THE DRY LOW LEVELS THROUGH THE AFTERNOON HOURS. SPLIT THE
WEATHER GRIDS FOR THE FIRST 12 HOURS INTO 3 HOUR BLOCKS. DID THIS
TO SHOW THE STUBBORNLY SLOW PROGRESS OF MEASURABLE PRECIPITATION
ACROSS THE REGION. DO EXPECT LOTS OF VIRGA AND GUSTY WINDS THIS
AFTERNOON AS THE ATMOSPHERE MOISTENS UP. DECIDED TO FLY THE LAKE
WIND ADVISORY WITH THE MARGINAL 15 TO 25 MPH WINDS DUE TO THE GUST
FACTOR THAT COULD SURPRISE IN EXPERIENCED BOATERS EARLY IN THE
SEASON.
TONIGHT WENT WITH HIGH POP LOW QPF/LITTLE OR CHANCE OF WETTING
RAIN SOLUTION. CONFIDENCE IS MODERATE... MODELS ALL ARE GOING FOR
A WETTING RAIN ACROSS MOST OF NORTHEAST MONTANA. HOWEVER THE MODEL
PERFORMANCE ON RAINFALL HAS BEEN POOR AND OVER FORECASTING
RAINFALL.
ON THURSDAY AS THE WINDS SWITCH TO THE WEST ACROSS THE AREA CLOUD
BASES WILL RISE AND AGAIN THE BOUNDARY LAYER SHOULD DRY OUT
KEEPING MEASURABLE PRECIPITATION VALUES LOW. THE ONE ISSUE THAT
COULD INCREASE POPS THURSDAY AFTERNOON IS VERY STEEP LAPSE RATES
WHICH COULD SPARK A THUNDERSTORM AND CREATE SMALL AREAS OF HIGHER
RAINFALL.
THURSDAY NIGHT THE DAKOTA LOW WILL CONTINUE TO DRIFT EAST KEEPING
MOST AREAS DRY. ON FRIDAY A LOW MOVES OFF THE ALBERTA ROCKIES AND
SLIDES ACROSS SASKATCHEWAN INTO NORTH DAKOTA IN THE NORTHWEST FLOW
AHEAD OF THE BUILDING RIDGE. THIS MIGHT BRING ANOTHER VERY SLIGHT
CHANCE OF WETTING RAINS WITH STRONGER SHOWERS ACROSS THE NORTHERN
TIER OF ZONES. OTHERWISE MORE DUST SETTLING SHOWERS WITH LITTLE
RAIN RELIEF EXPECTED. PROTON
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE LAST IN A SERIES OF SEVERAL SHORTWAVE DISTURBANCES FROM THE W
MOVES OUT OF THE AREA FRI NIGHT. THEN A BUILDING UPPER RIDGE FROM
THE S OVER THE WEEKEND BRINGS SUNNY AND WARMER WEATHER. THE RIDGE
BECOMES QUITE STRONG WITH 850 MB TEMPS TO AS HIGH AS 18-24C
MONDAY. THICKNESSES VALUES REACH 570 DM. THIS SHOULD DRIVE NE MT
HIGHS INTO THE UPPER 70S TO MID 80S...WHICH WILL APPROACH RECORD
HIGHS FOR THE DATE AT SOME LOCATIONS.
MODELS AGREE WITH A MOSTLY DRY...BUT FAIRLY STRONG COLD FRONT FROM THE
WNW MOVING ACROSS THE AREA TUE...WHICH WILL START A COOLING TREND.
THE ASSOCIATED UPPER TROUGH LAGS BEHIND...AND MODELS HAVE VARIED
ON TIMING...INTENSITY...AND MOVEMENT WITH THIS. ECMWF HAS BEEN
TOO QUICK TO BREAK DOWN THE RIDGE. MEANWHILE CMC GEM DEFLECTS BOTH
COLD FRONT AND TROUGH TO OUR N AND KEEPS THE RIDGE OVER OUR AREA...WHICH
DOES APPEAR POSSIBLE. GFS ENSEMBLES INDICATE THAT ANY OF THESE AND
OTHER SOLUTIONS ARE POSSIBLE TOO...SO LOW CONFIDENCE AT THE END OF
THE PERIOD. PREFER THE 00Z OPERATIONAL GFS THOUGH WHICH IS MORE
OF A MIDDLE GROUND SOLUTION...AND DOES BRING AT LEAST A SLIGHT
CHANCE OF SHOWERS BY WED. SIMONSEN
&&
.AVIATION...
A MID-MORNING MVFR FOG BANK AND LOW CEILING WILL PERSIST UNTIL
ABOUT 15Z OR 16Z FOR KOLF AND KSDY. AFTER WHICH...VFR CONDITIONS
WILL THEN RETURN TODAY FOR ALL TAF SITES ACROSS NORTHEAST MONTANA
AS PERIODS OF RAIN PUSH IN FROM THE WEST AND SOUTHWEST. AFTERNOON
WINDS FROM THE EAST WILL INCREASE INTO THE 15G25KT RANGE. LATE
THIS AFTERNOON AND TONIGHT...CEILINGS LOWER TO 4K FT AGL WITH
SCATTERED SHOWERS. EXPECT A STRATIFORM RAIN TO PERSIST THROUGH THE
END OF THIS TAF PERIOD WITH OCCASIONAL MVFR CONDITIONS. BMICKELSON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY UNTIL 9 PM MDT THIS EVENING FOR FORT PECK
LAKE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS GLASGOW MT
403 AM MDT WED APR 18 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH FRIDAY...
THE SHORT TERM FORECAST IS A HARD ONE TODAY FOR NORTHEAST
MONTANA... MANY VARIABLES PLAYING INTO THE FORECAST EQUATION FOR
THE NEXT 48 HOURS.
FOR THE FIRST 12 HOUR TOOK THE HRRR FOR THE POPS/QPF FORECAST. IT
HAS PREFORMED VERY WELL THIS SPRING SEASON. PLUS THE GFS/NAM AGAIN
ARE BRINGING HIGH QPF VALUES TO NORTHEAST MONTANA. THE MODELS HAVE
A POOR TRACK RECORD IN THE PAST MONTH WITH FORECASTING QPF OVER
NORTHEAST MONTANA WITH A TREMENDOUS WET BIAS. MODEL SOUNDINGS SHOW
AT THE GGW POINT ...ALONG WITH BUFR SOUNDINGS... A SLOW MOISTENING
OF THE DRY LOW LEVELS THROUGH THE AFTERNOON HOURS. SPLIT THE
WEATHER GRIDS FOR THE FIRST 12 HOURS INTO 3 HOUR BLOCKS. DID THIS
TO SHOW THE STUBBORNLY SLOW PROGRESS OF MEASURABLE PRECIPITATION
ACROSS THE REGION. DO EXPECT LOTS OF VIRGA AND GUSTY WINDS THIS
AFTERNOON AS THE ATMOSPHERE MOISTENS UP. DECIDED TO FLY THE LAKE
WIND ADVISORY WITH THE MARGINAL 15 TO 25 MPH WINDS DUE TO THE GUST
FACTOR THAT COULD SURPRISE IN EXPERIENCED BOATERS EARLY IN THE SEASON.
TONIGHT WENT WITH HIGH POP LOW QPF/LITTLE OR CHANCE OF WETTING
RAIN SOLUTION. CONFIDENCE IS MODERATE... MODELS ALL ARE GOING FOR
A WETTING RAIN ACROSS MOST OF NORTHEAST MONTANA. HOWEVER THE MODEL
PERFORMANCE ON RAINFALL HAS BEEN POOR AND OVER FORECASTING
RAINFALL.
ON THURSDAY AS THE WINDS SWITCH TO THE WEST ACROSS
THE AREA CLOUD BASES WILL RISE AND AGAIN THE BOUNDARY LAYER SHOULD
DRY OUT KEEPING MEASURABLE PRECIPITATION VALUES LOW. THE ONE
ISSUE THAT COULD INCREASE POPS THURSDAY AFTERNOON IS VERY STEEP
LAPSE RATES WHICH COULD SPARK A THUNDERSTORM AND CREATE SMALL
AREAS OF HIGHER RAINFALL.
THURSDAY NIGHT THE DAKOTA LOW WILL CONTINUE TO DRIFT EAST KEEPING
MOST AREAS DRY. ON FRIDAY A LOW MOVES OFF THE ALBERTA ROCKIES AND
SLIDES ACROSS SASKATCHEWAN INTO NORTH DAKOTA IN THE NORTHWEST FLOW
AHEAD OF THE BUILDING RIDGE. THIS MIGHT BRING ANOTHER VERY SLIGHT
CHANCE OF WETTING RAINS WITH STRONGER SHOWERS ACROSS THE NORTHERN
TIER OF ZONES. OTHERWISE MORE DUST SETTLING SHOWERS WITH LITTLE
RAIN RELIEF EXPECTED. PROTON
.LONG TERM...FRIDAY NIGHT THROUGH WEDNESDAY...
THE LAST IN A SERIES OF SEVERAL SHORTWAVE DISTURBANCES FROM THE W
MOVES OUT OF THE AREA FRI NIGHT. THEN A BUILDING UPPER RIDGE FROM
THE S OVER THE WEEKEND BRINGS SUNNY AND WARMER WEATHER. THE RIDGE
BECOMES QUITE STRONG WITH 850 MB TEMPS TO AS HIGH AS 18-24C
MONDAY. THICKNESSES VALUES REACH 570 DM. THIS SHOULD DRIVE NE MT
HIGHS INTO THE UPPER 70S TO MID 80S...WHICH WILL APPROACH RECORD
HIGHS FOR THE DATE AT SOME LOCATIONS.
MODELS AGREE WITH A MOSTLY DRY...BUT FAIRLY STRONG COLD FRONT FROM THE
WNW MOVING ACROSS THE AREA TUE...WHICH WILL START A COOLING TREND.
THE ASSOCIATED UPPER TROUGH LAGS BEHIND...AND MODELS HAVE VARIED
ON TIMING...INTENSITY...AND MOVEMENT WITH THIS. ECMWF HAS BEEN
TOO QUICK TO BREAK DOWN THE RIDGE. MEANWHILE CMC GEM DEFLECTS BOTH
COLD FRONT AND TROUGH TO OUR N AND KEEPS THE RIDGE OVER OUR AREA...WHICH
DOES APPEAR POSSIBLE. GFS ENSEMBLES INDICATE THAT ANY OF THESE AND
OTHER SOLUTIONS ARE POSSIBLE TOO...SO LOW CONFIDENCE AT THE END OF
THE PERIOD. PREFER THE 00Z OPERATIONAL GFS THOUGH WHICH IS MORE
OF A MIDDLE GROUND SOLUTION...AND DOES BRING AT LEAST A SLIGHT
CHANCE OF SHOWERS BY WED. SIMONSEN
&&
.AVIATION...
VFR...BUT WITH INCREASING CLOUDS 10 K FT AGL AND ABOVE TODAY.
W-SE WINDS INCREASE TO 10 TO 20KT. LATE THIS AFTERNOON AND
TONIGHT...CEILINGS LOWER TO 4K FT AGL WITH SCATTERED
SHOWERS...AND AN ISOLATED THUNDERSTORM OR TWO POSSIBLE AS WELL.
ALTHOUGH NOT AFFECTING ANY NE MT TAF SITE...THERE IS A CHANCE OF
SNOW MIXED WITH THE RAIN LATE TONIGHT ACROSS OUR MOST NORTHERN
LOCATIONS...INCLUDING DANIELS...SHERIDAN..AND NORTHERN VALLEY
COUNTIES. THESE AREAS COULD DROP TO 3 TO 5 MILE VISIBILITY AT
TIMES...WITH BROKEN CEILINGS 1-3K FT AGL. SIMONSEN
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
LAKE WIND ADVISORY FROM 9 AM THIS MORNING TO 9 PM MDT THIS
EVENING FOR FORT PECK LAKE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION...UPDATED
NWS OMAHA/VALLEY NE
1258 PM CDT WED APR 18 2012
.UPDATE...
.AVIATION...
18Z TAFS FOR KOFK/KLNK/KOMA.
MAIN AVIATION CONCERNS ARE CONDITIONS DETERIORATING FROM VFR TO
MVFR THURS MORNING ASSOCIATED WITH STRENGTHENING SFC BNDRY OVER
ERN NEB. EXPECT SCT PCPN ACTIVITY ALL TERMINALS MAINLY BETWEEN
09Z-15Z TIME FRAME UNTIL SFC BNDRY SLIPS SOUTH. POST-FRONTAL MVFR
CIGS PREVAILING THEN THE REST OF THE FCST PD.
DEE
.PREV DISCUSSION... /ISSUED 302 AM CDT WED APR 18 2012/
MAIN FORECAST CONCERN WILL BE POPS IN THE NEAR TERM AS QUIET AND
WARMER WEATHER IS EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK.
LATEST REGIONAL RADAR IMAGERY SHOWED BAND OF SHOWERS AND
THUNDERSTORMS PROGRESSING SOUTHEAST ACROSS THE NORTHERN PORTION
OF THE CWA. ACTIVITY IS ALONG A WEAK COLD FRONT OUT AHEAD OF A MID
LEVEL SHORTWAVE MOVING EWD THRU THE CENTRAL DAKOTAS. LATEST
SEVERAL RUNS OF THE HRRR HAVE HAD A GOOD HANDLE ON THIS LINE AND
EXPECT THE ACTIVITY TO EXIT THE SOUTHEASTERN FORECAST AREA AROUND
14Z.
WEAK FRONT WASHES OUT OVER THE AREA AND STRONG SOUTHERLY FLOW
RETURNS TONIGHT. ANOTHER WEAK SHORTWAVE WL MOVE THRU THE DAKOTAS
TONIGHT PUSHING A STRONGER COLD FRONT INTO THE FORECAST AREA
OVERNIGHT. THIS WILL BRING ANOTHER GOOD CHANCE FOR SCATTERED
SHOWERS AND THUNDERSTORMS OVERNIGHT AND INTO THURSDAY. THE FRONT
IS SLOW TO MOVE THRU AND LINGERS MUCH OF THE DAY THURSDAY UNTIL
STRONGER UPPER LEVEL SUPPORT ARRIVES THURSDAY NIGHT. CONTINUED
SMALL POPS IN OUR SOUTH LATE THURSDAY NIGHT INTO FRIDAY MORNING.
WARMING TREND ANTICIPATED FOR THE WEEKEND AND EARLY NEXT WEEK AS
AMPLIFIED UPPER RIDGE BUILDS OVER THE WESTERN CONUS. HIGHS IN THE
LOW 80S FORECAST BY TUESDAY.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
622 AM CDT WED APR 18 2012
.AVIATION...
12Z TAFS FOR KOFK...KLNK AND KOMA.
VFR CONDITIONS ARE EXPECTED THROUGH MOST OF THE TAF PERIOD.
SCATTERED SHOWERS EARLY WILL MOVE EAST OF KOMA AND KLNK...WITH
SCATTERED CLOUDS OR CLEAR SKIES TO FOLLOW. WINDS WILL AVERAGE
SOUTH OR SOUTHWEST AT KLNK AND KOMA...AND NORTH AT KOFK...BUT
SPEEDS SHOULD REMAIN AT OR BELOW 12KTS. A LOW PRESSURE SYSTEM
MOVING INTO THE REGION OVERNIGHT WILL BRING THE CHANCE FOR SHOWERS
AND THUNDERSTORMS TO ALL TAF SITES AFTER 06Z. COVERAGE IS STILL A
QUESTION...SO 12Z TAFS WILL REFLECT ONLY SHOWERS AND VFR CIGS.
DERGAN
&&
.PREV DISCUSSION... /ISSUED 302 AM CDT WED APR 18 2012/
DISCUSSION...
MAIN FORECAST CONCERN WILL BE POPS IN THE NEAR TERM AS QUIET AND
WARMER WEATHER IS EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK.
LATEST REGIONAL RADAR IMAGERY SHOWED BAND OF SHOWERS AND
THUNDERSTORMS PROGRESSING SOUTHEAST ACROSS THE NORTHERN PORTION
OF THE CWA. ACTIVITY IS ALONG A WEAK COLD FRONT OUT AHEAD OF A MID
LEVEL SHORTWAVE MOVING EWD THRU THE CENTRAL DAKOTAS. LATEST
SEVERAL RUNS OF THE HRRR HAVE HAD A GOOD HANDLE ON THIS LINE AND
EXPECT THE ACTIVITY TO EXIT THE SOUTHEASTERN FORECAST AREA AROUND
14Z.
WEAK FRONT WASHES OUT OVER THE AREA AND STRONG SOUTHERLY FLOW
RETURNS TONIGHT. ANOTHER WEAK SHORTWAVE WL MOVE THRU THE DAKOTAS
TONIGHT PUSHING A STRONGER COLD FRONT INTO THE FORECAST AREA
OVERNIGHT. THIS WILL BRING ANOTHER GOOD CHANCE FOR SCATTERED
SHOWERS AND THUNDERSTORMS OVERNIGHT AND INTO THURSDAY. THE FRONT
IS SLOW TO MOVE THRU AND LINGERS MUCH OF THE DAY THURSDAY UNTIL
STRONGER UPPER LEVEL SUPPORT ARRIVES THURSDAY NIGHT. CONTINUED
SMALL POPS IN OUR SOUTH LATE THURSDAY NIGHT INTO FRIDAY MORNING.
WARMING TREND ANTICIPATED FOR THE WEEKEND AND EARLY NEXT WEEK AS
AMPLIFIED UPPER RIDGE BUILDS OVER THE WESTERN CONUS. HIGHS IN THE
LOW 80S FORECAST BY TUESDAY.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
302 AM CDT WED APR 18 2012
.DISCUSSION...
MAIN FORECAST CONCERN WILL BE POPS IN THE NEAR TERM AS QUIET AND
WARMER WEATHER IS EXPECTED FOR THE WEEKEND INTO EARLY NEXT WEEK.
LATEST REGIONAL RADAR IMAGERY SHOWED BAND OF SHOWERS AND
THUNDERSTORMS PROGRESSING SOUTHEAST ACROSS THE NORTHERN PORTION
OF THE CWA. ACTIVITY IS ALONG A WEAK COLD FRONT OUT AHEAD OF A MID
LEVEL SHORTWAVE MOVING EWD THRU THE CENTRAL DAKOTAS. LATEST
SEVERAL RUNS OF THE HRRR HAVE HAD A GOOD HANDLE ON THIS LINE AND
EXPECT THE ACTIVITY TO EXIT THE SOUTHEASTERN FORECAST AREA AROUND
14Z.
WEAK FRONT WASHES OUT OVER THE AREA AND STRONG SOUTHERLY FLOW
RETURNS TONIGHT. ANOTHER WEAK SHORTWAVE WL MOVE THRU THE DAKOTAS
TONIGHT PUSHING A STRONGER COLD FRONT INTO THE FORECAST AREA
OVERNIGHT. THIS WILL BRING ANOTHER GOOD CHANCE FOR SCATTERED
SHOWERS AND THUNDERSTORMS OVERNIGHT AND INTO THURSDAY. THE FRONT
IS SLOW TO MOVE THRU AND LINGERS MUCH OF THE DAY THURSDAY UNTIL
STRONGER UPPER LEVEL SUPPORT ARRIVES THURSDAY NIGHT. CONTINUED
SMALL POPS IN OUR SOUTH LATE THURSDAY NIGHT INTO FRIDAY MORNING.
WARMING TREND ANTICIPATED FOR THE WEEKEND AND EARLY NEXT WEEK AS
AMPLIFIED UPPER RIDGE BUILDS OVER THE WESTERN CONUS. HIGHS IN THE
LOW 80S FORECAST BY TUESDAY.
KERN
&&
.AVIATION...06Z TAFS FOR KOFK...KOMA AND KLNK.
VFR CIGS WITH MID CLDS FLO080-012 WILL PUSH ACROSS THE TAF SITES
THROUGH 12Z. SOME LOWER VFR CIGS MAY DEVELOP AS SHOWERS AND A FEW
ISOLATED THUNDERSTORMS ACCOMPANY A COLD FRONT. THERE IS
INSTABILITY...AND MAY NEED TO ADD THUNDER AT THE SITE IF IT
BECOMES MORE PREVALENT ON THE SOUTHERN END OF THE LINE. BRISK
SOUTH TO SOUTHWEST WINDS AT 10 TO 20 KT WITH SOME HIGHER GUSTS
WILL GRADUALLY DECREASE BEHIND THE FRONT AFTER IT MOVES INTO
EASTERN NEBRASKA. INCLUDED LOW LEVEL WIND SHEAR THIS MORNING WITH
PROFILERS AT 45 TO 50KT IN ERN NEB. THE FRONT IS SLOW TO MOVE
THROUGH AND WILL AFFECT THE WIND SHIFTS...WITH THE WINDS BECOMING
NORTHWEST...THEN NORTHEAST...THEN SOUTHEAST THROUGH 06Z.
ZAPOTOCNY
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS BUFFALO NY
750 PM EDT THU APR 19 2012
.SYNOPSIS...
HIGH PRESSURE RIDGING ALONG THE EASTERN SEABOARD AND LOW PRESSURE
OVER THE MIDWEST WILL BRING WARMER AIR INTO THE REGION TONIGHT AND
FRIDAY. THE WARM WEATHER WILL COME TO A QUICK END AS A COLD FRONT
CROSSES THE REGION FRIDAY NIGHT AND SATURDAY. THIS FRONT WILL ALSO
BRING RAIN SHOWERS TO MUCH OF THE REGION. THE COOL AND POTENTIALLY
SHOWERY WEATHER WILL LAST THROUGH THE WEEKEND.
&&
.NEAR TERM /THROUGH FRIDAY/...
AN UPPER TROUGH DIGGING ACROSS THE UPPER PLAINS AND MIDWEST WILL
INVIGORATE A SURFACE LOW OVER MO/IA/IL TONIGHT...AND SUPPORT A WARM
FRONT ACROSS THE GREAT LAKES. THIS WARM FRONT WILL BRING A LAYER OF
MID LEVEL CLOUDINESS TO THE FORECAST AREA WHICH WILL BLANKET THE
REGION AND MAINTAIN MILDER TEMPERATURES THROUGH THE NIGHT. EXPECT
OVERNIGHT LOWS IN THE UPPER 40S TO THE LOWER 50S...SOME COOLER MID
40S FOR THE TUG HILL REGION. GUSTY SOUTHWESTERLY WINDS ACROSS METRO
BUFFALO NORTHEASTWARD TO NEAR ROCHESTER WILL DIMINISH THIS EVENING
WITH WINDS BECOMING LIGHT AND VARIABLE FOR MOST LOCATIONS.
LATE AFTERNOON SHOWERS OF SOUTHERN LOWER MICHIGAN SHOULD CONTINUE TO
LIFT TO THE NORTHEAST FOLLOWING THE 1000-500MB THICKNESS GRADIENT
AND SHOULD MISS THE FORECAST AREA AS IT MOVES INTO SOUTHERN ONTARIO.
12Z GFS AND NAM12 AS WELL AS CURRENT HRRR MODELS SUPPORT THIS
CONCEPT...SO WILL LEAVE ALL THE AREA DRY FOR THIS EVENING AND
TONIGHT.
AN INFLUX OF WARMER AIR WILL FOLLOW THE DRY PASSAGE OF THE WARM
FRONT ON FRIDAY. 850MB TEMPS AT 12 FRIDAY CLIMB TO NEAR +10C OVER
SOUTHWESTERN NY AND +8C FOR THE NORTH COUNTRY. THESE TEMPS ALOFT
ALONG WITH A DOWNSLOPING SOUTHERLY WIND WILL TRANSLATE TO AFTERNOON
TEMPERATURES IN THE LOWER TO MID 70S ACROSS THE FORECAST
AREA...UPPER 70S POSSIBLE FOR THE LOWER GENESEE VALLEY AND THE
NORTHERN FINGER LAKES TO THE LAKE ONTARIO PLAIN. ALTHOUGH THE
SURFACE TEMPS WILL WARM AND THERE WILL BE AN INCREASE IN SURFACE
DEWPOINTS...THERE WILL BE INSUFFICIENT INSTABILITY TO INVOKE
CONVECTION...THE MID LEVELS WILL BE RATHER MOIST AND SUPPORT
CLOUDINESS AND A MOIST LAPSE RATE WITH ONLY ABOUT 50-80 J/KG OF MID
LEVEL CAPE. THERE MAY BE SOME VIRGA FROM THE HIGH AND MID
CLOUDS...BUT DONT EXPECT MEASURABLE PRECIP DURING THE DAY ON FRIDAY.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/...
AT THE START OF THE PERIOD FRIDAY NIGHT AND SATURDAY A MID LEVEL
TROUGH WILL ADVANCE EAST ACROSS THE GREAT LAKES WITH AN ATTENDANT
SURFACE LOW MOVING FROM NEAR TORONTO FRIDAY EVENING TO MAINE BY
SATURDAY EVENING. LARGE SCALE FORCING FOR ASCENT WILL INCREASE LATER
FRIDAY NIGHT AS MID LEVEL HEIGHT FALLS AND PVA SPREAD EAST ACROSS
THE LOWER LAKES. THE RIGHT ENTRANCE REGION OF A 100+ KNOT UPPER
LEVEL JET WILL ALSO BE IN A FAVORABLE POSITION ON THE EAST SIDE OF
THE ADVANCING TROUGH TO PROVIDE UPPER LEVEL DIVERGENCE. AT THE
SURFACE A COLD FRONT WILL SURGE EAST ACROSS THE REGION BETWEEN
06Z-12Z SATURDAY. THERE WILL BE A NARROW CORRIDOR OF DECENT MOISTURE
ALONG THE FRONT WITH PWAT INCREASING TO 1-1.25 INCHES. GIVEN THE
LAYOUT OF THE LARGE SCALE FEATURES...THE COLD FRONT MAY END UP BEING
ANABATIC IN NATURE WITH MUCH OF THE LIFT AND RAIN ALONG AND BEHIND
THE SURFACE COLD FRONT.
WITH THIS IN MIND...EXPECT JUST SCATTERED LIGHT SHOWERS FRIDAY
EVENING ACROSS WESTERN NY AND THE NORTH COUNTRY...WITH A PERIOD OF
STEADIER SHOWERS ENTERING THE REGION DURING THE WEE HOURS OF
SATURDAY MORNING. 12Z MODEL GUIDANCE CONTINUES THE TREND OF A FASTER
EXIT OF THIS SYSTEM...SO EXPECT RAIN TO END IN WESTERN NY BY EARLY
TO MID MORNING SATURDAY...WITH THE BACK EDGE REACHING THE EASTERN
LAKE ONTARIO REGION BY MIDDAY OR EARLY AFTERNOON. RAINFALL AMOUNTS
LOOK MODEST WITH THIS SYSTEM... GENERALLY A TENTH TO QUARTER INCH
WITH PERHAPS A LITTLE MORE ACROSS THE SOUTHERN TIER AND EAST OF LAKE
ONTARIO...NOT ENOUGH TO ALLEVIATE THE DRY SOIL CONDITIONS. HIGH
PRESSURE WILL BUILD INTO THE UPPER LAKES AND NORTHWEST ONTARIO
PROVINCE BY SATURDAY AFTERNOON...BUT CLOUD COVER WILL LINGER ACROSS
MUCH OF THE AREA WITH JUST A FEW SUNNY BREAKS POSSIBLE IN THE FAR
WEST LATER IN THE AFTERNOON.
HIGH PRESSURE WILL CONTINUE TO BUILD INTO THE UPPER LAKES SATURDAY
NIGHT THROUGH SUNDAY NIGHT WITH A PLUME OF MOISTURE AND ASCENT
MOVING TO THE EAST COAST AND REMAINING TOO FAR EAST TO PRODUCE ANY
PRECIP BACK ACROSS OUR AREA. WE STARTED A DOWNWARD TREND IN POPS
YESTERDAY...AND GIVEN MODEL GUIDANCE IS STILL CONSISTENT ON A DRY
SUNDAY HAVE NOW REMOVED POPS ALTOGETHER. IT WILL BE COOL HOWEVER
WITH 850MB TEMPS DOWN AROUND -4C...SUPPORTING HIGHS IN THE UPPER 40S
TO LOWER 50S. NORTH-NORTHWEST FLOW CROSSING LAKE ONTARIO ALONG WITH
DAYTIME HEATING WILL LIKELY PRODUCE QUITE A BIT OF CLOUD COVER WITH
STEEP LOW LEVEL LAPSE RATES...ALTHOUGH SOME SUNNY BREAKS ARE
POSSIBLE ESPECIALLY LATER IN THE DAY ON THE LAKE PLAINS AS THE LAKES
FLIP FROM UNSTABLE TO STABLE DURING THE PEAK OF DIFFERENTIAL
HEATING. BOTH SATURDAY NIGHT AND SUNDAY NIGHT WILL BE CHILLY...BUT A
DECENT GRADIENT AND AT LEAST SOME CLOUD COVER MAY PREVENT ANY
FROST/FREEZE CONCERNS.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
FORECAST CONFIDENCE IS LOW FOR THE MONDAY THROUGH WEDNESDAY TIME
FRAME WITH A WIDE DISPARITY IN THE MEDIUM RANGE GUIDANCE FROM RUN TO
RUN AND BETWEEN VARIOUS MODELS. THE PAST FEW RUNS OF THE GFS...
INCLUDING THE LATEST 12Z RUN DEVELOPS A SURFACE LOW OFF THE MID
ATLANTIC COAST SUNDAY NIGHT...EVENTUALLY TRACKING INTO MAINE BY
MONDAY EVENING. THIS FARTHER EAST TRACK IS DUE TO A LATER AND LESS
COMPLETE PHASING OF SHORTWAVES OVER THE NORTHEAST QUADRANT OF THE
NATION. ON THE OTHER EXTREME...THE PAST TWO RUNS OF THE ECMWF HAVE
DEVELOPED AN EXTREMELY DEEP CUTOFF LOW OVER THE CENTRAL APPALACHIANS
SUNDAY NIGHT...WHICH THEN PIVOTS NORTH ACROSS THE LOWER LAKES ON
MONDAY. THIS FORCES THE STRONG COASTAL LOW TO TRACK INLAND ACROSS
EASTERN OR EVEN CENTRAL NY. THE CANADIAN GEM IS A COMPROMISE
SOLUTION WITH A SURFACE LOW TRACKING INLAND ACROSS CENTRAL NEW
ENGLAND. TAKING A LOOK AT THE 12Z GEFS ENSEMBLES...ABOUT HALF OF
THEM ARE MUCH FARTHER WEST THAN THE OPERATIONAL GFS...WHICH DOES
LEND SOME CREDENCE TO THE FARTHER WEST SOLUTIONS.
GIVEN THE HIGH DEGREE OF MODEL UNCERTAINTY...FOR NOW HAVE
ESSENTIALLY LEFT THE OLD FORECAST IN PLACE WITH A CHANCE OF RAIN OR
SNOW IN WESTERN NY EARLY NEXT WEEK...AND LIKELY FROM THE GENESEE
VALLEY INTO CENTRAL NY FOLLOWING AN AVERAGE TRACK OF ALL MODEL
GUIDANCE. THE ECMWF SOLUTION IS EXTREME AND NOT PARTICULARLY FAVORED
BY EAST COAST STORM CLIMATOLOGY...SO THE CHANCES OF THAT VERIFYING
ARE QUITE LOW. THAT SAID...EVEN SOME OF THE MORE CONSERVATIVE GEFS
ENSEMBLE MEMBERS WOULD PRODUCE A SIGNIFICANT LATE SEASON SNOWFALL
OVER PARTS OF THE NORTHEAST. STAY TUNED.
GIVEN THE HIGH DEGREE OF UNCERTAINTY FOR EARLY IN THE WEEK...THERE
IS ALSO LOW CONFIDENCE FOR WED-THURS AND FOR NOW WILL JUST GO WITH A
DRY FORECAST AND SLOWLY MODERATING TEMPERATURES.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR CONDITIONS WILL BE IN PLACE ACROSS ALL OF WESTERN AND NORTH
CENTRAL NEW YORK TONIGHT...DESPITE THE PRESENCE OF A STATIONARY
FRONT THAT STRETCHES ACROSS LAKES ERIE AND ONTARIO. WHILE PLENTY OF
ALTO-CU AND CIRRUS WILL BE ASSOCIATED WITH THIS FRONTAL
BOUNDARY...NO PRECIPITATION IS EXPECTED.
AN AREA OF LOW PRESSURE OVER LOWER MICHIGAN ON FRIDAY MORNING WILL
THEN TRACK NORTHEAST ALONG THE AFOREMENTIONED FRONTAL BOUNDARY SO
THAT IT WILL BE IN THE VCNTY OF TORONTO BY FRIDAY EVENING. THE
STALLED FRONT OVER LAKE ONTARIO WILL LIFT NORTH IN THE PROCESS...
AND THIS WILL PUSH THE BULK OF THE MID AND UPPER LEVEL MOISTURE
NORTH OF THE LAKE AS WELL. ALL THIS BEING SAID...VFR CONDITIONS WILL
REMAIN IN PLACE THROUGHOUT THE DAY.
AS THE AREA OF LOW PRESSURE MOVES EAST OF TORONTO FRIDAY NIGHT...IT
WILL DRAG ITS ASSOCIATED COLD FRONT ACROSS OUR REGION. THIS WILL
RESULT IN WIDESPREAD SHOWERS WITH OCCASIONAL MVFR CONDITIONS
POSSIBLE.
OUTLOOK...
FRIDAY NIGHT...VFR/MVFR WITH SHOWERS DEVELOPING.
SATURDAY...MVFR/IFR WITH RAIN SHOWERS LIKELY...TAPERING OFF IN THE
AFTERNOON.
SUNDAY...MAINLY VFR WITH A CHANCE OF SHOWERS.
MONDAY AND TUESDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
SOUTHWESTERLY WINDS WILL DIMINISH TONIGHT AND BECOME EASTERLY FOR
A WHILE...THEN WARMER AIR ACROSS THE LAKES LATE TONIGHT AND FRIDAY
WILL LIMIT THE WAVE FORMATION. A SURFACE LOW WILL CROSS THE LOWER
GREAT LAKES FRIDAY NIGHT DRAGGING A COLD FRONT ACROSS THE LAKES
AND BRINGING FRESH NORTHWESTERLIES BEHIND IT ON SATURDAY AND THE
COOLER AIR WILL INCREASE THE WAVES ON LAKES ERIE AND ONTARIO.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...WCH
NEAR TERM...WCH
SHORT TERM...HITCHCOCK
LONG TERM...HITCHCOCK
AVIATION...RSH
MARINE...WCH
AREA FORECAST DISCUSSION
NWS NEWPORT/MOREHEAD CITY NC
1111 PM EDT THU APR 19 2012
.SYNOPSIS...
A STATIONARY FRONT OFF THE NORTH CAROLINA COAST WILL LINGER INTO
FRIDAY. LOW PRESSURE WILL DEVELOP OVER THE WESTERN GULF STATES
SATURDAY AND TRACK NORTHEAST ALONG A COLD FRONT NEAR THE COAST
SUNDAY. THE LOW WILL CONTINUE NORTH OF THE REGION MONDAY AND
TUESDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. THE HIGH WILL
PASS SOUTH OF THE AREA WEDNESDAY.
&&
.NEAR TERM /THROUGH FRIDAY/...
AS OF 1050 PM THU...HIGH PRESSURE CONTINUES OVER THE MID-ATLANTIC
WITH WEAK LINGERING STATIONARY FRONT JUST OFF THE NC COAST. A WEAK
MID LEVEL TROUGH MOVING INTO ERN NC IS ENHANCING SOME LIGHT
SHOWERS ACROSS SE NC. 00Z NAM AND HRRR PICKING UP ON THE LIGHT
PCPN PRETTY WELL AND HAS IT SLOWLY LIFTING NE ACROSS THE CRYSTAL
COAST INTO THE OBX AREA THROUGH THE OVERNIGHT. VERY LIGHT QPF
ASSOC WITH THIS WITH ONLY A COUPLE HUNDREDTHS OF AN INCH EXPECTED.
NRN AREAS WILL CONTINUE TO SEE SOME CLEARING BUT BL REMAINS
FAIRLY MOIST AND THINK CLEARING SKIES WILL ENHANCE RADIATIONAL
COOLING WITH FOG REDEVELOPMENT LIKELY. TEMPS REMAIN ON TRACK AND
ONLY ADJUSTED FOR CURRENT TRENDS. WENT ON THE COOLER SIDE OF
GUIDANCE OVERNIGHT FOR LOWS GIVEN CURRENT TEMPS IN THE 60S EVEN
THOUGH EXPECT BKN-OVC SKIES...GENERALLY WENT WITH LOWS IN THE 50S.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/...
AS OF 3 PM THU...OVERALL EXPECT FAIRLY QUIET DAY ACROSS EASTERN
NC FRI. LOW CLOUDS AND PATCHY FOG COULD LINGER INTO EARLY FRI AM
BUT SHOULD BURN OFF FAIRLY QUICKLY. LOW LEVEL THICKNESS VALUES
AND OVERALL E/SE FLOW SUPPORT HIGH TEMPS IN THE MID TO UPPER 70S.
ISOLATED TO WIDELY SCT CONVECTION POSSIBLE FRIDAY AFTERNOON AND
EARLY EVENING...THOUGH OVERALL INSTABILITY LOOKS PRETTY MARGINAL
AND WITH LITTLE UPPER SUPPORT OTHER THAN SEABREEZE HAVE MAINTAINED
SLIGHT CHANCE POPS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
AS OF 230 PM THU...MAINLY DRY CONDITIONS FRI NIGHT INTO EARLY SAT
AS UPR TRF APPROACHES FROM THE W. WL CONT SMALL POP FRI NIGHT AS
ATMS WILL BE SLIGHTLY UNSTABLE. CONT CHC POP SAT AFTN INLAND AS
BEGIN TO SEE SOME LIFT IN ADVANCE OF UPR TRF/COLD FRONT AND
INSTABILITY SHLD REACH PEAK THIS TIME. INCREASE POPS TO HIGH CHC
SAT EVENING THEN LIKELY LATER SAT NIGHT AS DEEPER MOISTURE AND
GOOD LIFT OVERSPREAD THE AREA AHEAD OF UPR TRF. FOR NOW INSTAB
LOOKS WEAK AND SHEAR NOT REAL STRONG INIT SO SVR THREAT LOOKS
LIMITED. WIDESPREAD SHOWERS EXPECTED EARLY SUNDAY AS WAVE OF LOW
PRES ASSOC WITH SRN PART OF UPR TRF LIFTS NE ALONG THE FRONT. NAM
NOT SHOWING MUCH QPF HOWEVER OTHER MDLS QUITE WET SO UPPED POPS TO
JUST BELOW CATEGORICAL LATE SAT NIGHT AND FIRST PART OF SUNDAY.AS
THE LOW LIFTS TO THE N IT WILL PUSH COLD FRONT FURTHER OFFSHORE
WITH PRECIP DIMINISHING FROM W TO E SUN NIGHT. CONT SMALL POP MON
AND MON EVENING AS ADDITIONAL ENERGY SWINGS THRU THE UPR TRF
HOWEVER MOISTURE LIMITED SO NOT LOOKING FOR MUCH PRECIP. OVERALL
LOOKS LIKE WILL SEE STORM TOTALS OF AT LEAST 1/2 TO 1 INCH FROM
THIS SYSTEM AND COULD BE QUITE A BIT MORE ESPCLY CST IF FRONT WERE
TO SLOW DOWN OR STALL FOR A PERIOD SUNDAY.
DRY AND COOL CONDITIONS TUE AND WED AS DEEP UPR TRF SLOWLY MOVES
E. HGTS WILL BUILD LATER IN THE WEEK WITH TEMPS EXPECTED TO BE AT
OR ABOVE NORMAL FROM THU ON.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
SHORT TERM /THROUGH FRIDAY/...
AS OF 1050 PM THU...CLEARING CONTINUES TO SPREAD SWD ACROSS THE
NRN PORTION OF THE CWA BUT WEAK LIFT ASSOC WITH A WEAK UPPER
TROUGH WILL SPREAD CLOUDS AND LIGHT RAIN ACROSS SRN AREAS...MAINLY
ALONG THE COAST AND DON`T EXPECT THE CLEARING TO PUSH THROUGH ALL
OF THE CWA. ANY CLEARING THAT DOES OCCUR WILL ENHANCE RADIATIONAL
COOLING ALLOWING FOR GROUND FOG DEVELOPMENT WITH CONDITIONS
DROPPING TO BLOW IFR SHORTLY AFTERWARD. GUIDANCE NOT MUCH HELP
WITH NAM NOT REALIZING CURRENT STCU DECK ACROSS THE REGION AND GFS
MAINTAINING MVFR CONDITIONS THROUGH MIDNIGHT...THEN LOWERING CIGS
TO AOB IFR AFTER MIDNIGHT WITH NO CLEARING FIRST...BUT BOTH
INDICATING IFR OR BELOW AFTER DEVELOPING AFTER MIDNIGHT THROUGH
MID MORNING. EXPECT CIGS TO LIFT TO VFR AROUND MID DAY FRI WITH
LIGHT ELY WINDS BECOMING S/SELY IN THE AFTERNOON AN ONLY A SLIGHT
CHANCE OF A THUNDERSTORM...MAINLY ALONG THE SEABREEZE.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM THURSDAY...MAINLY VFR CONDITIONS ARE EXPECTED FRIDAY
NIGHT INTO SATURDAY OUTSIDE OF WIDELY SCATTERED CONVECTIVE
ACTIVITY. DETERIORATING CONDITIONS ARE EXPECTED SATURDAY NIGHT
INTO SUNDAY AS A STRONG UPPER SYSTEM AND ASSOCIATED SURFACE COLD
FRONT/DEVELOPING SURFACE LOW AFFECT EASTERN NC...WIDESPREAD MVFR
WITH PERIODS OF IFR CONDITIONS ARE EXPECTED. CONDITIONS SHLD
GRADUALLY IMPROVE SUN NIGHT WITH MAINLY VFR EARLY NEXT WEEK.
&&
.MARINE...
SHORT TERM /THROUGH FRIDAY/...
AS OF 750 PM THU...LATEST OBS SHOW N/NE WINDS 15KT OR LESS WITH
SEAS 4-6FT NORTH OF OCRACOKE AND 2-4FT SOUTH. LONG PERIOD EASTERLY
SWELL 12 SECONDS CONTINUES TO AFFECT THE COASTAL WATERS WILL BEGIN
TO SUBSIDE OVERNIGHT ALLOWING THE SEAS TO SUBSIDE TO 5FT FOR THE
CENTRAL AND NORTHERN WATERS AND WILL MAINTAIN SCA THROUGH 06Z.
WEAK FRONTAL BOUNDARY WILL CONTINUE TO LINGER NEAR THE NC WATERS
TONIGHT AND INTO FRIDAY BEFORE FINALLY DISSIPATING. WINDS AOB 15KT
WILL VEER THROUGH THE DAY FRI...BECOMING E/SE IN THE AFTERNOON AND
EVENING.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY...
AS OF 230 PM THURSDAY...MAINLY SRLY WINDS 10 TO 15 FRI NIGHT WILL
INCREASE TO 15 TO 20 KTS SATURDAY AS A COLD FRONT APPROACHES.
LINGERING E SWELL WILL KEEP SEAS IN THE 3 TO 5 FT RANGE THRU SAT
MORN WITH SOME 6 FT SEAS LIKELY SAT AFTN AS WINDS INCREASE. COLD
FRONT WILL REACH CST EARLY SUNDAY AND LOOKS LIKE WILL BE OFFSHORE
BY MIDDAY WITH MAINLY N WINDS 20 TO 25 KTS AFTER FROPA. THESE
WINDS WILL BUILD SEAS TO 6 TO 8 FT OVER OUTER WATERS LATER SUN AND
SUN NIGHT. AS LOW PRES LIFTS N OF REGION MON FLOW WILL BECOME NNW
AT MAINLY 15 TO 20 KTS...SEAS WILL GRAD SUBSIDE TO 3 TO 5 FT MON.
WINDS WILL GRAD BECOME MORE WRLY INTO TUE AS THE LOW LIFTS FURTHER
TO THE N AND HIGH PRES BUILDS IN FROM THE W. WINDS EXPECTED TO
DIMINISH TO 10 TO 15 KTS TUE WITH SEAS 2 TO 3 FEET MOST WATER LATE
TUE.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT FRIDAY FOR AMZ150-152-154.
&&
$$
SYNOPSIS...CQD
NEAR TERM...SK
SHORT TERM...CQD
LONG TERM...RF
AVIATION...RF/SK/CQD
MARINE...RF/SK/CQD
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
1042 PM EDT THU APR 19 2012
.SYNOPSIS...
A NEARLY STATIONARY FRONT LOCATED JUST OFFSHORE WILL DISSIPATE
TONIGHT THROUGH FRIDAY. LOW PRESSURE IS EXPECTED TO DEVELOP IN THE
NORTHERN GULF OF MEXICO SATURDAY...MOVING UP THE SOUTHEAST ATLANTIC
COAST ON SUNDAY WITH A SIGNIFICANT RAIN EVENT FOR AT LEAST THE
COASTAL CAROLINAS. HIGH PRESSURE WILL BUILD IN FROM THE WEST THROUGH
THE MIDDLE OF NEXT WEEK WITH DRY WEATHER AND BELOW-NORMAL
TEMPERATURES.
&&
.NEAR TERM /THROUGH 6 AM EDT FRIDAY/...
AS OF 1030 PM EDT THURSDAY...LATEST 88D PCPN COVERAGE WIDELY
SCATTERED AT THE MOMENT. COASTAL COUNTIES WILL REMAIN UNDER THE
THREAT FOR SHRA INTO THE PRE-DAWN HRS OF FRIDAY. THE HRRR SEEMS TO
BE HANDLING THIS PCPN MUCH BETTER THAN ORIGINALLY THOUGHT. THE WEAK
MID LEVEL S/W MOVING OFFSHORE JUST SOUTH OF THE ILM CWA SEEMS TO
HAVE THE AVAILABLE DYNAMICS TO AID IN THE GENERATION OF PCPN ALONG
THE IMMEDIATE COAST AND THEIR ADJACENT ATL WATERS. 00Z MHX AND CHS
RAOBS ILLUSTRATE NEARLY SATURATED CONDITIONS SFC THRU 800MB. THE
OVERCAST LOW LEVEL STRATUS CLOUD DECK TO BECOME THE DOMINATE SKY
CONDITION FOR THE REMAINDER OF THE OVERNIGHT. WITH REFERENCE TO FOG
POTENTIAL...THE GFS MODEL MOS GUIDANCE INDICATES WIDESPREAD FOG WITH
POCKETS OF DENSE...AND IS FAVORED OVER THE NAM MOS WHICH INDICATES A
MUCH LOWER THREAT FOR FOG.
LOOKING AT LOW LEVEL PROGGED PARTIAL THICKNESSES AND 8H PROGGED
TEMPS...NO ADDITIONAL CAA IS EXPECTED...IN FACT IT FAVORS A NEUTRAL
TEMP ADVECTION DURING THE REMAINDER OF THE OVERNIGHT. TONIGHTS MINS
REMAIN UNCHANGED...WHICH REMAINS ON THE HIGHER SIDE OF MOS
GUIDANCE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...A FLAT H5 RIDGE ACROSS THE SOUTHEASTERN UNITED
STATES ON FRIDAY WILL LIFT EAST ON SATURDAY AS A LARGE UPPER LOW
BEGINS TO TAKE SHAPE OVER THE NORTHERN GULF OF MEXICO. THE LOW WILL
EJECT AN IMPULSE UP THE COAST SATURDAY NIGHT RESULTING IN INCREASING
CHANCES FOR CONVECTION...ESPECIALLY LATER IN THE SHORT TERM PERIOD.
AT THE SURFACE...LOW PRESSURE IS EXPECTED TO RIDE UP JUST OFF THE
COAST SATURDAY NIGHT...THUS THE HIGHEST QPF AMOUNTS ARE EXPECTED TO
BE ALONG THE COASTAL COUNTIES. MAV/MET NUMBERS ARE RELATIVELY CLOSE
THROUGH THE PERIOD...AND SAW NO REASON AT THIS TIME TO STRAY TOO FAR
FROM THEM. THESE TEMPERATURES WILL RANGE ABOVE NORMAL EACH PERIOD
AHEAD OF THE AFOREMENTIONED DEVELOPING UPPER LOW.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...MEDIUM RANGE MODELS APPEAR TO BE DIVIDING INTO
TWO CAMPS REGARDING THE SIGNIFICANT SYSTEM FOR LATE IN THE WEEKEND
EXTENDING INTO EARLY NEXT WEEK. THE OPERATIONAL GFS IS ADVERTISING
AN EVER INCREASING PROGRESSIVE TREND WITH THE MID LEVEL LOW WHILE
THE GFS PARALLEL (GFS EXPERIMENTAL MODEL) IS SLOWER AND MORE IN LINE
WITH THE ECMWF SUITE OF PRODUCTS.
WILL CONTINUE TO FOLLOW THE HPC FAVORED SLOWER SOLUTION AS IT OFFERS
MORE CONTINUITY WITH PREVIOUS FORECAST. LARGE SWATH OF MOISTURE
EXPECTED TO INUNDATE THE FORECAST AREA SUNDAY WITH MID LEVEL
DEFORMATION BEING THE DRIVING FORCE.
THE REMAINDER OF THE FORECAST...FROM MONDAY ON IS DRY WITH
TEMPERATURES BELOW CLIMATOLOGY AT LEAST THROUGH WEDNESDAY. MIXED
BOUNDARY LAYER SHOULD KEEP TEMPERATURES IN THE MIDDLE 40S TUESDAY
MORNING WITH A MODIFYING AIRMASS BUT MORE CONDUCIVE RADIATIONAL
CONDITIONS YIELDING A DEGREE OR TWO LOWER WEDNESDAY MORNING. DAYTIME
HIGHS...SOMEWHAT BELOW CLIMATOLOGY EARLY WILL QUICKLY MODERATE TO
SEASONAL NORMALS BY WEDNEDAY AND THURSDAY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...MVFR CEILINGS SOLIDLY IN PLACE...AND WILL SLOWLY LOWER
FOR DIURNAL REASONS. A WEAK DISTURBANCE RIDING UP THE COAST COULD
GIVE THE COASTAL TERMINALS A SPRINKLE OR TWO...NO AVIATION IMPACT.
TONIGHT...IFR CEILINGS/VIS A GOOD BET...POSSIBLY LIFR. THIS WEDGE
WILL STAY IN PLACE THROUGH A GOOD PORTION OF THE MORNING HOURS
FRIDAY...FINALLY SCATTERING TO VFR BY MIDDAY...POSSIBLY LATER. LIGHT
NORTHEAST WINDS WILL CONTINUE OVERNIGHT...BECOMING EAST SOUTHEAST
FRIDAY AFTERNOON.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH ISOLATED SHOWERS FRIDAY
AFTERNOON. INTERMITTENT MVFR/POSSIBLE IFR CONDITIONS WITH SCATTERED
SHOWERS SATURDAY. NUMEROUS SHOWERS/TEMPO IFR POSSIBLE
SUNDAY...MAINLY NEAR THE COAST. VFR MONDAY AND TUESDAY WITH ISOLATED
SHOWERS MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1030 PM EDT THURSDAY...COLD FRONT LIES NEARLY STATIONARY JUST
E AND S OF THE ILM COASTAL WATERS. NORTHEAST TO EAST 10-15 KT WINDS
WILL PREMIERE ACROSS ALL ILM WATERS OVERNIGHT...WITH A BRIEF WINDOW
OF SUSTAINED 15 KT DUE TO THE SLIGHTLY PINCHED SFC PRESSURE
GRADIENT. SIGNIFICANT SEAS WILL PRIMARILY BE DRIVEN TONIGHT BY A
SOLID EASTERLY 1-2 FOOT GROUND SWELL EXHIBITING 12 TO 14 SECOND
PERIODS. THE ADDITION OF THE LOCALLY PRODUCED WIND DRIVEN WAVES TO
SIGNIFICANT SEAS...WILL COMBINE WITH THE SWELL TO YIELD AN OVERALL 2
TO 4 FT SIG. SEAS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...THE WEAK FRONT OVER THE WATERS FRIDAY MORNING
WILL GRADUALLY DISSIPATE. THE FLOW WILL BECOME SOUTHERLY DURING THE
AFTERNOON AFTER THE FRONT DISSOLVES. THE SOUTHERLY PRESSURE GRADIENT
WILL KEEP SOUTHERLY FLOW AROUND 15 KNOTS OR LESS SATURDAY INTO
SATURDAY EVENING. THEN WITH POSSIBLE LOW BEGINNING TO RIDE UP THE
COAST THE FLOW MAY BACK OVERNIGHT SATURDAY NIGHT. SEAS WILL BE
DOMINATED BY AN EASTERLY SWELLS FRIDAY. THE SWELLS WILL GRADUALLY
WEAKEN AND BECOME OVERTAKEN BY HIGHER FREQUENCY SOUTHERLY WAVES
SATURDAY.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...MAIN FORECAST CHALLENGE WILL BE WIND
DIRECTIONS EARLY IN THE PERIOD AS A COASTAL FRONT WILL BE MEANDERING
SOMEWHERE IN THE AREA. VIA HPC GRAPHICS...START OUT THE PERIOD WITH
SOUTH TO SOUTHEAST WINDS QUICKLY BACKING TO NORTHEAST BY THE EARLY
AFTERNOON SUNDAY AS LOW PRESSURE MOVES OFFSHORE AND UP THE COAST.
NORTH TO NORTHWEST WINDS FROM LATE SUNDAY ON WITH SPEEDS GENERALLY
AROUND 15 KNOTS. A SECONDARY SHORTWAVE IN THE NORTHWEST FLOW ALOFT
WILL INCREASE WINDS SLIGHTLY LATE TUESDAY. WAVEWATCH SEAS LOOK GOOD
WITH 3-5 FEET EARLY DECREASING TO 2-4 FEET MONDAY AND TUESDAY WITH
THE OFFSHORE FLOW.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH
SHORT TERM...SRP
LONG TERM...SHK
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
745 PM EDT THU APR 19 2012
.SYNOPSIS...
A NEARLY STATIONARY FRONT LOCATED JUST OFFSHORE WILL DISSIPATE
TONIGHT THROUGH FRIDAY. LOW PRESSURE IS EXPECTED TO DEVELOP IN THE
NORTHERN GULF OF MEXICO SATURDAY...MOVING UP THE SOUTHEAST ATLANTIC
COAST ON SUNDAY WITH A SIGNIFICANT RAIN EVENT FOR AT LEAST THE
COASTAL CAROLINAS. HIGH PRESSURE WILL BUILD IN FROM THE WEST THROUGH
THE MIDDLE OF NEXT WEEK WITH DRY WEATHER AND BELOW-NORMAL
TEMPERATURES.
&&
.NEAR TERM /THROUGH 6 AM EDT FRIDAY/...
AS OF 730 PM EDT THURSDAY...LATEST 88D PCPN COVERAGE RATHER ISOLATED
AT THE MOMENT. COASTAL COUNTIES WILL REMAIN UNDER THE THREAT FOR
ISOLATED SHRA THROUGH MID TO LATE THIS EVENING. THE HRRR HOWEVER IS
INDICATING AROUND MIDNIGHT INTO THE FRIDAY PRE-DAWN HRS FOR PCPN TO
BRIEFLY MOVE BACK ONSHORE DUE TO A WEAK MID LEVEL S/W MOVING
OFFSHORE JUST SOUTH OF THE ILM CWA. AM NOT BUYING THIS ONSHORE
MOVEMENT OF PCPN...AND AS A RESULT WILL KEEP THE MAJORITY OF THE
PROGGED PCPN OVER THE ATLANTIC WATERS OVERNIGHT.
LOOKING AT LOW LEVEL PROGGED PARTIAL THICKNESSES AND 8H PROGGED
TEMPS...NO ADDITIONAL CAA IS EXPECTED...IN FACT IT FAVORS A NEUTRAL
TEMP ADVECTION DURING THE OVERNIGHT. THE CURRENT BROKEN/OVC CLOUD
CONDITIONS WILL REMAIN OVERNIGHT...WITH THE POSSIBILITY OF A LOW
LEVEL STRATUS DECK AND A FOG THREAT AS INDICATED BY THE PREVIOUS
NEAR TERM DISCUSSION. THIS WILL RESULT WITH TONIGHTS MINS ON THE
HIGHER SIDE OF GUIDANCE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...A FLAT H5 RIDGE ACROSS THE SOUTHEASTERN UNITED
STATES ON FRIDAY WILL LIFT EAST ON SATURDAY AS A LARGE UPPER LOW
BEGINS TO TAKE SHAPE OVER THE NORTHERN GULF OF MEXICO. THE LOW WILL
EJECT AN IMPULSE UP THE COAST SATURDAY NIGHT RESULTING IN INCREASING
CHANCES FOR CONVECTION...ESPECIALLY LATER IN THE SHORT TERM PERIOD.
AT THE SURFACE...LOW PRESSURE IS EXPECTED TO RIDE UP JUST OFF THE
COAST SATURDAY NIGHT...THUS THE HIGHEST QPF AMOUNTS ARE EXPECTED TO
BE ALONG THE COASTAL COUNTIES. MAV/MET NUMBERS ARE RELATIVELY CLOSE
THROUGH THE PERIOD...AND SAW NO REASON AT THIS TIME TO STRAY TOO FAR
FROM THEM. THESE TEMPERATURES WILL RANGE ABOVE NORMAL EACH PERIOD
AHEAD OF THE AFOREMENTIONED DEVELOPING UPPER LOW.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...MEDIUM RANGE MODELS APPEAR TO BE DIVIDING INTO
TWO CAMPS REGARDING THE SIGNIFICANT SYSTEM FOR LATE IN THE WEEKEND
EXTENDING INTO EARLY NEXT WEEK. THE OPERATIONAL GFS IS ADVERTISING
AN EVER INCREASING PROGRESSIVE TREND WITH THE MID LEVEL LOW WHILE
THE GFS PARALLEL (GFS EXPERIMENTAL MODEL) IS SLOWER AND MORE IN LINE
WITH THE ECMWF SUITE OF PRODUCTS.
WILL CONTINUE TO FOLLOW THE HPC FAVORED SLOWER SOLUTION AS IT OFFERS
MORE CONTINUITY WITH PREVIOUS FORECAST. LARGE SWATH OF MOISTURE
EXPECTED TO INUNDATE THE FORECAST AREA SUNDAY WITH MID LEVEL
DEFORMATION BEING THE DRIVING FORCE.
THE REMAINDER OF THE FORECAST...FROM MONDAY ON IS DRY WITH
TEMPERATURES BELOW CLIMATOLOGY AT LEAST THROUGH WEDNESDAY. MIXED
BOUNDARY LAYER SHOULD KEEP TEMPERATURES IN THE MIDDLE 40S TUESDAY
MORNING WITH A MODIFYING AIRMASS BUT MORE CONDUCIVE RADIATIONAL
CONDITIONS YIELDING A DEGREE OR TWO LOWER WEDNESDAY MORNING. DAYTIME
HIGHS...SOMEWHAT BELOW CLIMATOLOGY EARLY WILL QUICKLY MODERATE TO
SEASONAL NORMALS BY WEDNEDAY AND THURSDAY.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...MVFR CEILINGS SOLIDLY IN PLACE...AND WILL SLOWLY LOWER
FOR DIURNAL REASONS. A WEAK DISTURBANCE RIDING UP THE COAST COULD
GIVE THE COASTAL TERMINALS A SPRINKLE OR TWO...NO AVIATION IMPACT.
TONIGHT...IFR CEILINGS/VIS A GOOD BET...POSSIBLY LIFR. THIS WEDGE
WILL STAY IN PLACE THROUGH A GOOD PORTION OF THE MORNING HOURS
FRIDAY...FINALLY SCATTERING TO VFR BY MIDDAY...POSSIBLY LATER. LIGHT
NORTHEAST WINDS WILL CONTINUE OVERNIGHT...BECOMING EAST SOUTHEAST
FRIDAY AFTERNOON.
EXTENDED OUTLOOK...PREDOMINANTLY VFR WITH ISOLATED SHOWERS FRIDAY
AFTERNOON. INTERMITTENT MVFR/POSSIBLE IFR CONDITIONS WITH SCATTERED
SHOWERS SATURDAY. NUMEROUS SHOWERS/TEMPO IFR POSSIBLE
SUNDAY...MAINLY NEAR THE COAST. VFR MONDAY AND TUESDAY WITH ISOLATED
SHOWERS MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM EDT THURSDAY...COLD FRONT LIES NEARLY STATIONARY JUST E
AND S OF THE LOCAL BUOYS. NORTH TO NORTHEAST 10-15 KT WINDS ARE NOW
OCCURRING ACROSS ALL OF THE ILM WATERS. COULD SEE A BRIEF WINDOW OF
WIND SPEEDS A SOLID 15 KT DUE TO THE SLIGHTLY PINCHED SFC PRESSURE
GRADIENT. SIGNIFICANT SEAS WILL PRIMARILY BE DRIVEN TONIGHT BY A
SOLID EASTERLY NEARLY 1-2 FOOT GROUND SWELL EXHIBITING 12 TO 14
SECOND PERIODS. THE ADDITION OF THE LOCALLY PRODUCED WIND DRIVEN
WAVES...WILL COMBINE WITH THE SWELL TO YIELD 2 TO 4 FT SIG. SEAS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...THE WEAK FRONT OVER THE WATERS FRIDAY MORNING
WILL GRADUALLY DISSIPATE. THE FLOW WILL BECOME SOUTHERLY DURING THE
AFTERNOON AFTER THE FRONT DISSOLVES. THE SOUTHERLY PRESSURE GRADIENT
WILL KEEP SOUTHERLY FLOW AROUND 15 KNOTS OR LESS SATURDAY INTO
SATURDAY EVENING. THEN WITH POSSIBLE LOW BEGINNING TO RIDE UP THE
COAST THE FLOW MAY BACK OVERNIGHT SATURDAY NIGHT. SEAS WILL BE
DOMINATED BY AN EASTERLY SWELLS FRIDAY. THE SWELLS WILL GRADUALLY
WEAKEN AND BECOME OVERTAKEN BY HIGHER FREQUENCY SOUTHERLY WAVES
SATURDAY.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...MAIN FORECAST CHALLENGE WILL BE WIND
DIRECTIONS EARLY IN THE PERIOD AS A COASTAL FRONT WILL BE MEANDERING
SOMEWHERE IN THE AREA. VIA HPC GRAPHICS...START OUT THE PERIOD WITH
SOUTH TO SOUTHEAST WINDS QUICKLY BACKING TO NORTHEAST BY THE EARLY
AFTERNOON SUNDAY AS LOW PRESSURE MOVES OFFSHORE AND UP THE COAST.
NORTH TO NORTHWEST WINDS FROM LATE SUNDAY ON WITH SPEEDS GENERALLY
AROUND 15 KNOTS. A SECONDARY SHORTWAVE IN THE NORTHWEST FLOW ALOFT
WILL INCREASE WINDS SLIGHTLY LATE TUESDAY. WAVEWATCH SEAS LOOK GOOD
WITH 3-5 FEET EARLY DECREASING TO 2-4 FEET MONDAY AND TUESDAY WITH
THE OFFSHORE FLOW.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH
SHORT TERM...SRP
LONG TERM...SHK
AVIATION...HDL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
228 AM EDT WED APR 18 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL APPROACH FROM THE WEST LATE TODAY AND
TONIGHT BRINGING UNSETTLED WEATHER TO THE REGION. A STRONG STORM
SYSTEM IS EXPECTED TO BRING THE THREAT OF HEAVY RAIN OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 915 PM...
MOISTURE AND POTENTIAL ENERGY QUITE LIMITED WITH SCATTERED
CONVECTION LOW TOPPED AT THIS TIME. MOST MODELS CONTINUE TO
ATTEMPT TO DEVELOP PRECIPITATION TONIGHT ALONG THE BOUNDARY NEAR
SOUTH CAROLINA. HOWEVER THE RUC MODEL CONTINUES TO SHOW LIMITED
MOISTURE THROUGHOUT THE AIR COLUMN AND ONLY WEAK LOW LEVEL
CONVERGENCE IN THAT AREA. TO THE WEST CONVERGENCE LOCKED IN OVER
THE FOOTHILLS WITH MODELS OCCASIONALLY PRODUCING CONVERGENCE AND
LIFT IN THE WESTERN PIEDMONT. BEST CONVERGENCE WILL CONTINUE TO BE
OVER THE MOUNTAINS AND THE WESTERN FOOTHILLS TONIGHT. ISOLATED
RAINFALL AMOUNTS COULD BE IN EXCESS OF ONE INCH IN THE WEST... BUT
BASIN AVERAGES WILL GENERALLY BE QUITE LOW... AT A FEW HUNDREDTHS
OUTSIDE THE HEAVIEST SHOWERS. WILL LEAVE LOW LIKELY POPS IN THE
FAR WEST WITH CHANCE TO SLIGHT CHANCE POPS AS ONE MOVES EAST.
NORTHEAST FLOW WITH LOW LEVEL THICKNESSES AT SUNRISE WEDNESDAY
FALLING ABOUT 25 METERS FROM THIS MORNING. LOW TEMPERATURES MID
50S NORTH TO LOWER 60S SOUTH.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 155 PM WEDNESDAY...
MODELS CONTINUE TO ADVERTISE THE CURRENT MID/UPPER TROUGH OVER THE
TENNESSEE VALLEY WILL PROGRESS SLOWLY EAST AND WEAKEN WITH TIME.
SURFACE HIGH PRESSURE WILL CONTINUE TO STRENGTHEN OVER OUR PIEDMONT
DAMMING REGION LOCALLY ENHANCED BY QPF TODAY AND TONIGHT. BY
12Z/THU... THE REMNANT MID/UPPER WAVE WILL SHIFT OFFSHORE AND THIS
WILL LEAVE A WEAK SURFACE HIGH PRESSURE IN PLACE FROM OFF THE NEW
ENGLAND COAST SOUTHWESTWARD INTO THE NC/SC PIEDMONT. CLEARING SHOULD
BE SLOW DUE TO THE LOW LEVEL RESIDUAL CAD EVENT AND THE WEAK
PRESSURE GRADIENT FOLLOWING THE UPPER TROUGH`S PASSAGE. WE WILL
MAINTAIN A LOW CHANCE OF LIGHT RAIN/DRIZZLE EARLY THURSDAY... WITH
OVERCAST SKIES EXPECTED TO BECOME PARTLY SUNNY DURING THE AFTERNOON.
HIGHS WILL SLOWLY RECOVER INTO THE LOWER TO MID 70S.
WEAK HIGH PRESSURE WILL LINGER OVER THE STATE THROUGH FRIDAY.
HOWEVER... THE MID/UPPER LEVEL FLOW WILL BEGIN TO BECOME MORE
AMPLIFIED WITH TIME AS AN UPPER LEVEL LOW AND TROUGH DIGS SE INTO
THE LOWER MISSISSIPPI VALLEY AND NORTHERN GULF COAST REGION FRI-FRI
NIGHT. THIS WILL MEAN AN INCREASING SW FLOW ALOFT AND AN INCREASE IN
MID AND HIGH LEVEL MOISTURE BEGINNING FRIDAY. EXPECT PARTLY CLOUDY
CONDITIONS THU NIGHT AND FRI. LOWS GENERALLY 52-57. HIGHS 75-80.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 220 AM WEDNESDAY...
...A POTENTIAL HEAVY RAIN EVENT THIS WEEKEND CONTINUES...
THE LATEST MODELS REMAIN ON COURSE FOR A VERY WET WEEKEND FOR OUR
REGION. WE WILL NOT STRAY FAR FROM THE HPC MODEL PREFERENCES WHICH
INCLUDE A BLEND OF THE MOST RECENT 00Z/GFS/12Z ECMWF/00Z UKMET
COMPROMISE WITH INCREASING CONFIDENCE. THIS WOULD FAVOR A STRONG
SURFACE LOW PRESSURE TRACK NE FROM THE NORTHERN GULF COAST SATURDAY
AFTERNOON... TO NEAR CHARLESTON OR SAVANNAH BY LATE SUNDAY... THEN
NEAR WILMINGTON 12Z/MONDAY. A LARGE FETCH OF DEEP MOISTURE FROM OFF
THE GULF OF MEXICO AND GULF STREAM/WESTERN ATLANTIC IS EXPECTED TO
BE TAPPED INTO THE SYSTEM AS IT APPROACHES. CURRENT INDICATIONS ARE
THAT THE SYSTEM MAY BE RELATIVELY SLOW MOVING DUE TO THE NATURE OF
DEEP SOUTH CUT OFF LOWS AND THE POTENTIAL FOR THE MORE SOUTHWESTERLY
TRENDS OF RECENT FAVORED MODELS IN THE DEVELOPMENT OF THE MID LEVEL
CUT OFF LOW.
RIGHT NOW... IT APPEARS THAT SHOWERS/ISO THUNDERSTORMS WILL
DEVELOP/OVERSPREAD NC FROM THE SOUTH SATURDAY AFTERNOON. PERIODS OF
RAIN ARE EXPECTED SATURDAY NIGHT AND SUNDAY. THERE MAY BE A LULL IN
THE RAIN IF THE MID LEVEL DRY SLOT AFFECTS THE REGION LATE SUNDAY...
WITH THE POTENTIAL FOR ADDITIONAL SHOWERS WITH THE UPPER LOW AGAIN
SUNDAY NIGHT INTO MONDAY. QPF OF 1-3 INCHES LOOKS FAVORABLE.
THE POTENTIAL FOR WIDESPREAD SOAKING RAIN AND EVEN SOME FLOODING
APPEAR TO BE THE MAIN WEATHER HAZARDS FOR THE UPCOMING WEEKEND
STORM. THE FLASH FLOOD GUIDANCE HAS BEEN HIGH (4+ INCHES IN 12 HOURS
AND 2+ INCHES IN NON-URBAN AREAS IN 1 HOUR) RECENTLY DUE TO THE LACK
OF RAIN IN THE PAST 2 WEEKS. HOWEVER... NW PIEDMONT ZONES HAD
LOCALLY 1 TO 1.5 INCHES OF RAIN LAST EVENING AND AN ADDITIONAL 0.5
TO 1 INCH WITH THE CURRENT EVENT WILL REALLY MAKE THOSE THRESHOLDS
COME DOWN. WHILE FLASH FLOODING WOULD NOT BE A MAJOR CONCERN
INITIALLY... IT MAY BECOME AN ISSUE BY LATE IN THE WEEKEND IF WE DO
GET THE PROJECTED SOAKING.
THE SEVERE THREAT WOULD BE MINIMAL GIVEN THE PROJECTED STORM TRACK.
THE BEST CHANCE OF THUNDERSTORMS WOULD BE SATURDAY (ON THE LEADING
EDGE OF THE DEEP MOISTURE SHIELD) ARRIVING FROM THE SOUTH DURING THE
AFTERNOON.
SENSIBLE WEATHER... MOSTLY CLOUDY FRIDAY NIGHT WITH A SLIGHT CHANCE
OF SHOWERS. LOWS 58-63. SHOWERS DEVELOPING SATURDAY... A CHANCE OF
THUNDERSTORMS. HIGHS IN THE 70S TO AROUND 80. PERIODS OF RAIN SAT
NIGHT AND SUNDAY. SLIGHT CHANCE OF THUNDERSTORMS. LOWS IN THE 60S.
HIGHS 65-75 N TO SE.
A CHANCE OF SHOWERS SUNDAY NIGHT AND MONDAY. LOWS 50S. HIGHS IN THE
60S. BECOMING MOSTLY SUNNY TUESDAY. HIGHS IN THE 60S.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 225 AM WEDNESDAY...
BETWEEN ONE LOW AMPLITUDE MID-LEVEL DISTURBANCE OVER SOUTHWESTERN VA
AND ANOTHER MORE POTENT ONE OVER THE GULF COAST STATES...A BRIEF
LULL IN THE CURRENT SHOWER AND THUNDERSTORM ACTIVITY AFFECTING THE
TRIAD TERMINALS (KINT/KGSO) AND KRDU SHOULD OCCUR BETWEEN
APPROXIMATELY 09Z-20Z TODAY...AND RESULT IN CONTINUED GENERALLY VFR
CONDITIONS AT ALL CENTRAL NC TERMINALS THROUGH MOST OF WEDNESDAY.
HOWEVER...THE CLOSER APPROACH OF THE AFOREMENTIONED MID-UPPER
DISTURBANCE FROM THE GULF COAST STATES...AND RESULTANT UPLIFT OF AIR
ATOP GENERALLY NORTHEASTERLY FLOW AT THE SURFACE...WILL RESULT IN
THE LOWERING OF CEILINGS TO MVFR RANGE -- AND THE DEVELOPMENT OF
LIGHT RAIN -- FROM WEST TO EAST ACROSS CENTRAL NC LATE THIS
AFTERNOON AND THIS EVENING. THE DEVELOPMENT OF THE RAIN AND
RESULTANT COLD AIR DAMMING SHOULD CAUSE CEILINGS AND VISIBILITIES TO
LOWER FURTHER TO IFR AND MVFR...RESPECTIVELY -- LOWEST AT TRIAD
TERMINALS -- OVERNIGHT.
OUTLOOK...CONDITIONS WILL GRADUALLY IMPROVE TO MVFR OR LOW VFR BY
EARLY THU AFTERNOON...BUT THE CONTINUED PRESENCE OF THE RESIDUAL
COLD AIR DAMMING HIGH PRESSURE RIDGE OVER THE MIDDLE ATLANTIC REGION
SUGGESTS AT LEAST A MEDIUM CHANCE OF THE REDEVELOPMENT OF IFR
CONDITIONS THU NIGHT. THEN SIMILAR TO THU...ANY IFR CONDITIONS
SHOULD GRADUALLY LIFT TO MVFR OR LOW VFR ON FRI. A POTENTIALLY
SIGNIFICANT STORM SYSTEM MAY AFFECT CENTRAL NC WITH ADVERSE AVIATION
CONDITIONS DURING THE WEEKEND.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...RLH
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS RALEIGH NC
220 AM EDT WED APR 18 2012
.SYNOPSIS...
AN UPPER LEVEL TROUGH WILL APPROACH FROM THE WEST LATE TODAY AND
TONIGHT BRINGING UNSETTLED WEATHER TO THE REGION. A STRONG STORM
SYSTEM IS EXPECTED TO BRING THE THREAT OF HEAVY RAIN OVER THE
WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 915 PM...
MOISTURE AND POTENTIAL ENERGY QUITE LIMITED WITH SCATTERED
CONVECTION LOW TOPPED AT THIS TIME. MOST MODELS CONTINUE TO
ATTEMPT TO DEVELOP PRECIPITATION TONIGHT ALONG THE BOUNDARY NEAR
SOUTH CAROLINA. HOWEVER THE RUC MODEL CONTINUES TO SHOW LIMITED
MOISTURE THROUGHOUT THE AIR COLUMN AND ONLY WEAK LOW LEVEL
CONVERGENCE IN THAT AREA. TO THE WEST CONVERGENCE LOCKED IN OVER
THE FOOTHILLS WITH MODELS OCCASIONALLY PRODUCING CONVERGENCE AND
LIFT IN THE WESTERN PIEDMONT. BEST CONVERGENCE WILL CONTINUE TO BE
OVER THE MOUNTAINS AND THE WESTERN FOOTHILLS TONIGHT. ISOLATED
RAINFALL AMOUNTS COULD BE IN EXCESS OF ONE INCH IN THE WEST... BUT
BASIN AVERAGES WILL GENERALLY BE QUITE LOW... AT A FEW HUNDREDTHS
OUTSIDE THE HEAVIEST SHOWERS. WILL LEAVE LOW LIKELY POPS IN THE
FAR WEST WITH CHANCE TO SLIGHT CHANCE POPS AS ONE MOVES EAST.
NORTHEAST FLOW WITH LOW LEVEL THICKNESSES AT SUNRISE WEDNESDAY
FALLING ABOUT 25 METERS FROM THIS MORNING. LOW TEMPERATURES MID
50S NORTH TO LOWER 60S SOUTH.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY/...
AS OF 155 PM WEDNESDAY...
MODELS CONTINUE TO ADVERTISE THE CURRENT MID/UPPER TROUGH OVER THE
TENNESSEE VALLEY WILL PROGRESS SLOWLY EAST AND WEAKEN WITH TIME.
SURFACE HIGH PRESSURE WILL CONTINUE TO STRENGTHEN OVER OUR PIEDMONT
DAMMING REGION LOCALLY ENHANCED BY QPF TODAY AND TONIGHT. BY
12Z/THU... THE REMNANT MID/UPPER WAVE WILL SHIFT OFFSHORE AND THIS
WILL LEAVE A WEAK SURFACE HIGH PRESSURE IN PLACE FROM OFF THE NEW
ENGLAND COAST SOUTHWESTWARD INTO THE NC/SC PIEDMONT. CLEARING SHOULD
BE SLOW DUE TO THE LOW LEVEL RESIDUAL CAD EVENT AND THE WEAK
PRESSURE GRADIENT FOLLOWING THE UPPER TROUGH`S PASSAGE. WE WILL
MAINTAIN A LOW CHANCE OF LIGHT RAIN/DRIZZLE EARLY THURSDAY... WITH
OVERCAST SKIES EXPECTED TO BECOME PARTLY SUNNY DURING THE AFTERNOON.
HIGHS WILL SLOWLY RECOVER INTO THE LOWER TO MID 70S.
WEAK HIGH PRESSURE WILL LINGER OVER THE STATE THROUGH FRIDAY.
HOWEVER... THE MID/UPPER LEVEL FLOW WILL BEGIN TO BECOME MORE
AMPLIFIED WITH TIME AS AN UPPER LEVEL LOW AND TROUGH DIGS SE INTO
THE LOWER MISSISSIPPI VALLEY AND NORTHERN GULF COAST REGION FRI-FRI
NIGHT. THIS WILL MEAN AN INCREASING SW FLOW ALOFT AND AN INCREASE IN
MID AND HIGH LEVEL MOISTURE BEGINNING FRIDAY. EXPECT PARTLY CLOUDY
CONDITIONS THU NIGHT AND FRI. LOWS GENERALLY 52-57. HIGHS 75-80.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 220 AM WEDNESDAY...
...A POTENTIAL HEAVY RAIN EVENT THIS WEEKEND CONTINUES...
THE LATEST MODELS REMAIN ON COURSE FOR A VERY WET WEEKEND FOR OUR
REGION. WE WILL NOT STRAY FAR FROM THE HPC MODEL PREFERENCES WHICH
INCLUDE A BLEND OF THE MOST RECENT 00Z/GFS/12Z ECMWF/00Z UKMET
COMPROMISE WITH INCREASING CONFIDENCE. THIS WOULD FAVOR A STRONG
SURFACE LOW PRESSURE TRACK NE FROM THE NORTHERN GULF COAST SATURDAY
AFTERNOON... TO NEAR CHARLESTON OR SAVANNAH BY LATE SUNDAY... THEN
NEAR WILMINGTON 12Z/MONDAY. A LARGE FETCH OF DEEP MOISTURE FROM OFF
THE GULF OF MEXICO AND GULF STREAM/WESTERN ATLANTIC IS EXPECTED TO
BE TAPPED INTO THE SYSTEM AS IT APPROACHES. CURRENT INDICATIONS ARE
THAT THE SYSTEM MAY BE RELATIVELY SLOW MOVING DUE TO THE NATURE OF
DEEP SOUTH CUT OFF LOWS AND THE POTENTIAL FOR THE MORE SOUTHWESTERLY
TRENDS OF RECENT FAVORED MODELS IN THE DEVELOPMENT OF THE MID LEVEL
CUT OFF LOW.
RIGHT NOW... IT APPEARS THAT SHOWERS/ISO THUNDERSTORMS WILL
DEVELOP/OVERSPREAD NC FROM THE SOUTH SATURDAY AFTERNOON. PERIODS OF
RAIN ARE EXPECTED SATURDAY NIGHT AND SUNDAY. THERE MAY BE A LULL IN
THE RAIN IF THE MID LEVEL DRY SLOT AFFECTS THE REGION LATE SUNDAY...
WITH THE POTENTIAL FOR ADDITIONAL SHOWERS WITH THE UPPER LOW AGAIN
SUNDAY NIGHT INTO MONDAY. QPF OF 1-3 INCHES LOOKS FAVORABLE.
THE POTENTIAL FOR WIDESPREAD SOAKING RAIN AND EVEN SOME FLOODING
APPEAR TO BE THE MAIN WEATHER HAZARDS FOR THE UPCOMING WEEKEND
STORM. THE FLASH FLOOD GUIDANCE HAS BEEN HIGH (4+ INCHES IN 12 HOURS
AND 2+ INCHES IN NON-URBAN AREAS IN 1 HOUR) RECENTLY DUE TO THE LACK
OF RAIN IN THE PAST 2 WEEKS. HOWEVER... NW PIEDMONT ZONES HAD
LOCALLY 1 TO 1.5 INCHES OF RAIN LAST EVENING AND AN ADDITIONAL 0.5
TO 1 INCH WITH THE CURRENT EVENT WILL REALLY MAKE THOSE THRESHOLDS
COME DOWN. WHILE FLASH FLOODING WOULD NOT BE A MAJOR CONCERN
INITIALLY... IT MAY BECOME AN ISSUE BY LATE IN THE WEEKEND IF WE DO
GET THE PROJECTED SOAKING.
THE SEVERE THREAT WOULD BE MINIMAL GIVEN THE PROJECTED STORM TRACK.
THE BEST CHANCE OF THUNDERSTORMS WOULD BE SATURDAY (ON THE LEADING
EDGE OF THE DEEP MOISTURE SHIELD) ARRIVING FROM THE SOUTH DURING THE
AFTERNOON.
SENSIBLE WEATHER... MOSTLY CLOUDY FRIDAY NIGHT WITH A SLIGHT CHANCE
OF SHOWERS. LOWS 58-63. SHOWERS DEVELOPING SATURDAY... A CHANCE OF
THUNDERSTORMS. HIGHS IN THE 70S TO AROUND 80. PERIODS OF RAIN SAT
NIGHT AND SUNDAY. SLIGHT CHANCE OF THUNDERSTORMS. LOWS IN THE 60S.
HIGHS 65-75 N TO SE.
A CHANCE OF SHOWERS SUNDAY NIGHT AND MONDAY. LOWS 50S. HIGHS IN THE
60S. BECOMING MOSTLY SUNNY TUESDAY. HIGHS IN THE 60S.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
AS OF 815 PM TUESDAY...
SHOWERS AND THUNDERSTORMS AND ASSOCIATED BRIEF SUB VFR
CONDITIONS... MAINLY AT KINT/KGSO DUE TO THE PROXIMITY OF A
SURFACE FRONT THERE...WILL REMAIN A POSSIBILITY THROUGH ABOUT 9 TO
11 PM... BEFORE DIMINISHING WITH THE LOSS OF DAYTIME HEATING AND
RESULTANT INSTABILITY. OTHERWISE...GENERALLY VFR CONDITIONS WILL
PERSIST THROUGH TONIGHT. MEANWHILE...THE APPROACH OF AN UPPER
LEVEL TROUGH ON WEDNESDAY WILL AID IN THE DEVELOPMENT OF LOWERING
CEILINGS AND RAIN POTENTIAL AS WARMER AIR TO OUR SOUTH RISES ATOP
COOLER AIR ASSOCIATED WITH A HIGH PRESSURE SYSTEM THAT WILL EXPAND
ACROSS VIRGINIA. ASSOCIATED CEILINGS WILL GRADUALLY LOWER TO MVFR
RANGE -- FIRST AT KFAY DURING THE MORNING HOURS -- THEN ELSEWHERE
THROUGH LATE AFTERNOON. IN ADDITION... FORECAST SOUNDINGS INDICATE
MOISTENING THROUGHOUT THE DEPTH OF THE ATMOSPHERE...WHICH SUGGESTS
THE AFOREMENTIONED PROBABILITY OF RAIN WILL ALSO INCREASE FROM
WEST TO EAST WITH THE APPROACH OF THE UPPER LEVEL TROUGH LATE IN
THE DAY. WINDS WILL REMAIN LIGHT FROM THE NORTHEAST THROUGH
WEDNESDAY.
OUTLOOK...MVFR CONDITIONS WILL LIKELY BECOME IFR OVERNIGHT
WEDNESDAY...AND PERSIST INTO AT LEAST EARLY THURSDAY IN
ASSOCIATION WITH THE DEVELOPMENT OF A COLD AIR DAMMING WEDGE.
WHEN THE COLD AIR DAMMING WEDGE WILL ERODE AND VFR CONDITIONS WILL
RETURN REMAINS DIFFICULT TO ASCERTAIN AT THIS TIME. IT IS POSSIBLE
THAT MVFR AND PERIODIC IFR (OVERNIGHT) CEILINGS MAY LINGER THROUGH
THURSDAY/FRIDAY IN ASSOCIATION WITH A REMNANT COLD AIR DAMMING
WEDGE AND LOW LEVEL SOUTHERLY RETURN FLOW. A POTENTIALLY
SIGNIFICANT STORM SYSTEM MAY AFFECT THE CAROLINAS OVER THE
WEEKEND...THOUGH UNCERTAINTY REMAINS HIGH WITH THIS SYSTEM AS
WELL.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...BADGETT
NEAR TERM...RLH
SHORT TERM...BADGETT
LONG TERM...BADGETT
AVIATION...MWS
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
906 AM EDT WED APR 18 2012
.SYNOPSIS...
A WAVE OF LOW PRESSURE AFFECTS MAINLY EASTERN WEST VIRGINIA AND
SOUTHWEST VIRGINIA TODAY. HIGH PRESSURE THURSDAY AND FRIDAY. A STORM
SYSTEM FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
9 AM UPDATE. NOW ITS A MATTER OF WATCHING RADAR TRENDS TO SEE HOW
FAR THE NORTHERN EDGE OF THE RAIN WILL GET. HAVE ADJUSTED NORTHERN
EDGE A BIT FARTHER NORTH PER RADAR TRENDS...BUT STILL MOSTLY SOUTH
AND EAST OF HTS-CKB LINE. RAINFALL AMOUNTS WILL RANGE FROM AROUND A
HALF INCH SOUTHERN AND CENTRAL MOUNTAINS TO LESS THAN AROUND A TENTH
OF AN INCH TO NEAR THE CRW-CKB LINE...NOT MUCH WORTH NOTING NORTH OF
THERE.
UPDATED...
PUSHED POP GRADIENT A LITTLE FURTHER NW THIS MORNING. LATEST RADAR
MOSAIC AND OBS SHOW TIGHT PCPN SHIELD RUNNING ALONG 119/I79
CORRIDOR AND GENERALLY HOLDING THIS LINE. THUS HAVE USED THIS AS
ORIENTATION FOR DETERMINISTIC POPS WITH ACE ACROSS MTNS. SHOULD
SEE THIS SLOWLY PUSH OFF TO E LATER THIS MORNING...WITH MTNS
STAYING IN RA THRU AFTN.
PREVIOUS DISCUSSION BELOW...
THERE CONT TO BE SOME DISAGREEMENT WITH NW EXTENT OF MEASURABLE
PCPN THIS MORNING WITH THE NAM THE LONE GUN KEEP BULK OF QPF
ACROSS THE MTNS. MOST OTHER GUIDANCE HAS SHIFTED SOME TO NW WITH
MEASURABLE QPF...TAKING .1 TO .25 INCH CONTOUR THRU THE COAL
FIELDS TO ABOUT CRW AREA AND N UP I79 CORRIDOR. PLACEMENT OF LIFT
AND FORCING SIMILAR THOUGH. LOOKING AT MDL SOUNDINGS...ONE SEES
WHERE NAM IS HOLDING ON DRY AIR NEAR THE SFC W OF MTNS AS OTHER
MDLS INCLUDING THE RUC SATURATE THE COLUMN BY 12Z W TO CRW. LATEST
RADAR MOSAIC SHOWS SOLID AREA OF MAINLY -RA OVER SW VA AND S WV
MTNS ATTM. THIS IS TRYING TO PUSH NW SLOWLY BUT HAVING A HARD TIME
GIVEN DRY AIR IN FRONT OF IT. WILL NUDGE HIGHER POPS A HAIR NW
09-15Z THIS MORNING BUT NOT AS MUCH AS MODEL CONSENSUS SUGGESTS
WITH A BELIEF THE NAM MAY BE HANDLING THE BL MOISTURE BETTER AS
EVEN WHERE THERE IS RA OUT THERE...NOT SEEING ANY VSBY
RESTRICTIONS OR LOW CIGS CURRENTLY. WILL CONT TO MONITOR NEXT FEW
HRS FOR ANY FURTHER ADJUSTMENT TO NW.
OTHERWISE REMAINDER OF PREV FCST LOOKS GOOD. S/W TROF AXIS PUSHES
THRU THIS AFTN TAKING MUCH OF THE DEEP MOISTURE WITH IT AS SFC WAVE
PUSHES OFF TO NE. WILL GRADUALLY BRING POPS DOWN FROM W TO E THIS
AFTN...WITH AREA POP FREE BY 03Z. CONCERNING CLDS...WILL HOLD WV/SW
VA ZONES IN CLDS MUCH OF THE DAY AND ALLOW FOR SOME CLEARING ACROSS SE
OH/NE KY LATER IN AFTN. MAY SEE LOW STRATUS HOLD IN MTNS TONIGHT
WITH FG FOR ANY AREAS THAT RECEIVE RA THAT MANAGE TO CLR.
WILL LEAN TOWARD LWR NUMBERS FOR TDY GIVEN ABUNDANCE OF CLDS AND RA
ACROSS MTNS AND NUDGE TOWARD WARMER GUIDANCE ACROSS SE OH WHERE
SOME PARTIAL CLEARING MAY BE REALIZED THIS AFTN. WENT WITH WARMER
GUIDANCE FOR LOWS TONIGHT EAST OF OH RVR WITH SOME LINGERING CLDS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MODELS SHOW HIGH PRESSURE OVER THE REGION FOR THURSDAY AND FRIDAY.
FOR SATURDAY...MODELS DISAGREE WITH EACH OTHER AND CHANGE WITH EVERY
RUN. THIS DOES NOT LEAD TO A HIGH CONFIDENCE FORECAST. CURRENT
PACKAGE IS SUPPORTED BY THE CANADIAN MODEL...SO WILL STAY THE COURSE
FOR NOW UNTIL CONFIDENCE LEVELS INCREASE IN A SOLUTION.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AT THE OUTSET OF THE PERIOD FRIDAY EVENING A TROUGH WILL BE DIGGING
SOUTHWARD THROUGH THE CENTRAL CONUS...WITH POSITIVELY-TILTED AXIS
ROUGHLY FROM UPPER MID-WEST TO TEXAS. AT THE SURFACE A FRONT WILL BE
QUASI-STATIONARY TO THE NORTHWEST OF AREA OVER CENTRAL AND WESTERN
OHIO. TRIMMED BACK POPS OVER THE AREA FRI EVE WITH THIS IN MIND.
BOTH OPERATIONAL EXTENDED MODELS IS GOOD AGREEMENT WITH REGARD TO
THIS TROUGH CLOSING OFF ON ITS SOUTHERN END OVER THE SE TEXAS/LA
REGION BY SAT MORNING AND PROGRESSING THIS LOW EASTWARD ALONG THE
GULF COAST TOWARDS THE FLORIDA PANHANDLE BY EARLY SUN. GEFS MEAN
HEIGHT SOMEWHAT SURPRISINGLY KEEPS THIS LOW OPEN AND THEREFORE A BIT
MORE PROGRESSIVE...WITH ONLY FOUR OF ITS MEMBERS DEPICTING A CLOSURE
AT SUN 06Z. HOWEVER...BOTH NCEP AND EC ENSEMBLE MEAN HEIGHTS DO SHOW
THIS LOW CLOSING OFF AND THUS WILL BASE THE FORECAST ON THIS
SOLUTION.
SATURDAY THE UPPER LOW MOVING ACROSS THE GULF COAST WITH SFC
LOW...ALONG WITH A TROUGH MOVING ACROSS THE GREAT LAKES
REGION...WILL FINALLY ALLOW THE FRONT TO THE NORTHWEST TO BEGIN
PUSHING SE ACROSS THE AREA. STILL SOME DIFFERENCES IN TIMING BUT AT
THIS POINT THE FRONT IS EXPECTED TO BE AROUND THE OHIO RIVER AREA BY
18Z SAT AND NEAR THE EASTERN CWA BORDER BY 00Z SUN. LIFT AND
ABUNDANT LOW LEVEL MOISTURE STILL SUPPORT INCREASING CHANCES OF RAIN
SATURDAY AND SATURDAY EVENING. BEYOND THIS PERIOD MODELS BEGIN TO
DIVERGE WITH RESPECT TO THE DETAILS SURROUNDING CLOSED LOW AND
NORTHERN TROUGH...WITH THE GFS MORE PROGRESSIVE IN MOVING THE CLOSED
LOW NE AND INTO PHASE WITH THE DIVING NORTHERN TROUGH BY EARLY
MON...AND THE EC MUCH SLOWER IN PROGRESSION AND KEEPING THE TWO
SYSTEMS SEPARATE. NO REAL LEANING ONE WAY OR THE OTHER WHEN IT COMES
TO ENSEMBLES HERE...AND WITH NO REAL WAY TO DIFFERENTIATE AM
INCLINED TO BELIEVE THE SLOWER SOLN AS MODELS TEND TO BE MORE
PROGRESSIVE THAN REALITY WITH CLOSED SYSTEMS. THIS SOLUTION KEEPS
THE NORTHERN TROUGH DOMINANT IN ITS MOVING PRECIP EAST OF AREA
QUICKLY AFTER SUNDAY. HOWEVER...AGAIN WITH THE UNCERTAINTY I WILL
KEEP SOME MENTION OF POPS IN FOR MONDAY INTO TUESDAY.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
13Z WEDNESDAY TO 12Z THURSDAY...
13Z UPDATE...HAVE ADJUSTED NORTHERN EDGE OF RAIN A BIT FARTHER NORTH
TODAY...BUT STILL MOSTLY EAST OF A HTS-CKB LINE. IN TURN...INTRODUCED
QUICKER PREVAILING IFR CONDITIONS INTO SOUTHERN AND CENTRAL
MOUNTAINS THIS MORNING...AND OCCASIONAL MVFR CEILINGS MAY CREEP
NORTH AND WEST TO NEAR THE I79 CORRIDOR INCLUDING CRW BEFORE
SHIFTING EAST THIS AFTERNOON. ELSEWHERE...LITTLE CHANGE.
PREVIOUS DISCUSSION...
S/W TROF MOVING THRU COMBINED WITH ISENTROPIC LIFT AND SFC WAVE
WILL PROVIDE FOR MAINLY -RA ACROSS ALONG AND EAST OF US119/I79
CORRIDOR THRU 15Z BEFORE CONFINING ACROSS MTNS. GENERALLY MVFR
CIGS AND VSBY DEVELOPING ACROSS THE WV MTNS. EXCEPTION WILL ACROSS
EASTERN SLOPES WHERE SE FLOW NEAR SFC WILL ALLOW FOR IFR CIGS TDY.
ELSEWHERE...-RA MAY PUSH FURTHER W TO A KCRW TO KCKB LINE. HOWEVER
EXPECTING MAINLY VFR CONDITIONS WITH CIGS LOWERING INTO LOW END OF
RANGE AND VSBY REMAINING UNRESTRICTED. SYS SLOWLY PULLS E WITH
GRADUAL CLEARING ACROSS SE OH THIS AFTN. CLDS WILL HANG TOUGH E OF
OH RVR THRU 00Z AS LLVL MOISTURE SLOW TO DEPART. EXPECT MVFR CIGS
OVER MTNS TO LWR INTO IFR TONIGHT WITH VSBY APPROACHING IFR AS
WELL...INCLUDING KBKW. LIFR STRATUS POSSIBLE ACROSS AFTER 06Z MTN
TAF SITES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF MVFR CIGS THIS MORNING
AND TDY. EXTENT OF -RA MAY VARY. IFR CIGS MAY EXPAND FURTHER W
FROM EASTERN SLOPES TDY TO INCLUDE KBKW. LOW STRATUS AND SOME FG MAY
DEVELOP ACROSS WV LOWLANDS TONIGHT ESPECIALLY IN AREAS THAT
RECEIVED RAINFALL.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY M L L L M L L L L H H H
HTS CONSISTENCY H M L M M M M M H H H H
BKW CONSISTENCY M L M M M M M M L L L L
EKN CONSISTENCY M L L L H H H M M M M M
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H M M L L H H H H
AFTER 12Z THURSDAY...
IFR CONDITIONS TONIGHT SOUTHWEST VIRGINIA AND THE SOUTHERN WV
MOUNTAINS.
IFR CONDITIONS POSSIBLE FRIDAY NIGHT AND SATURDAY IN CLOUDS AND
PRECIPITATION.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...JMV/30
SHORT TERM...RPY
LONG TERM...50
AVIATION...JMV/30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
658 AM EDT WED APR 18 2012
.SYNOPSIS...
A WAVE DEVELOPS AND AFFECTS MAINLY THE MOUNTAINS TODAY. HIGH
PRESSURE THURSDAY AND FRIDAY. A STORM SYSTEM FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED...
PUSHED POP GRADIENT A LITTLE FURTHER NW THIS MORNING. LATEST RADAR
MOSAIC AND OBS SHOW TIGHT PCPN SHIELD RUNNING ALONG 119/I79
CORRIDOR AND GENERALLY HOLDING THIS LINE. THUS HAVE USED THIS AS
ORIENTATION FOR DETERMINISTIC POPS WITH ACE ACROSS MTNS. SHOULD
SEE THIS SLOWLY PUSH OFF TO E LATER THIS MORNING...WITH MTNS
STAYING IN RA THRU AFTN.
PREVIOUS DISCUSSION BELOW...
THERE CONT TO BE SOME DISAGREEMENT WITH NW EXTENT OF MEASURABLE
PCPN THIS MORNING WITH THE NAM THE LONE GUN KEEP BULK OF QPF
ACROSS THE MTNS. MOST OTHER GUIDANCE HAS SHIFTED SOME TO NW WITH
MEASURABLE QPF...TAKING .1 TO .25 INCH CONTOUR THRU THE COAL
FIELDS TO ABOUT CRW AREA AND N UP I79 CORRIDOR. PLACEMENT OF LIFT
AND FORCING SIMILAR THOUGH. LOOKING AT MDL SOUNDINGS...ONE SEES
WHERE NAM IS HOLDING ON DRY AIR NEAR THE SFC W OF MTNS AS OTHER
MDLS INCLUDING THE RUC SATURATE THE COLUMN BY 12Z W TO CRW. LATEST
RADAR MOSAIC SHOWS SOLID AREA OF MAINLY -RA OVER SW VA AND S WV
MTNS ATTM. THIS IS TRYING TO PUSH NW SLOWLY BUT HAVING A HARD TIME
GIVEN DRY AIR IN FRONT OF IT. WILL NUDGE HIGHER POPS A HAIR NW
09-15Z THIS MORNING BUT NOT AS MUCH AS MODEL CONSENSUS SUGGESTS
WITH A BELIEF THE NAM MAY BE HANDLING THE BL MOISTURE BETTER AS
EVEN WHERE THERE IS RA OUT THERE...NOT SEEING ANY VSBY
RESTRICTIONS OR LOW CIGS CURRENTLY. WILL CONT TO MONITOR NEXT FEW
HRS FOR ANY FURTHER ADJUSTMENT TO NW.
OTHERWISE REMAINDER OF PREV FCST LOOKS GOOD. S/W TROF AXIS PUSHES
THRU THIS AFTN TAKING MUCH OF THE DEEP MOISTURE WITH IT AS SFC WAVE
PUSHES OFF TO NE. WILL GRADUALLY BRING POPS DOWN FROM W TO E THIS
AFTN...WITH AREA POP FREE BY 03Z. CONCERNING CLDS...WILL HOLD WV/SW
VA ZONES IN CLDS MUCH OF THE DAY AND ALLOW FOR SOME CLEARING ACROSS SE
OH/NE KY LATER IN AFTN. MAY SEE LOW STRATUS HOLD IN MTNS TONIGHT
WITH FG FOR ANY AREAS THAT RECEIVE RA THAT MANAGE TO CLR.
WILL LEAN TOWARD LWR NUMBERS FOR TDY GIVEN ABUNDANCE OF CLDS AND RA
ACROSS MTNS AND NUDGE TOWARD WARMER GUIDANCE ACROSS SE OH WHERE
SOME PARTIAL CLEARING MAY BE REALIZED THIS AFTN. WENT WITH WARMER
GUIDANCE FOR LOWS TONIGHT EAST OF OH RVR WITH SOME LINGERING CLDS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MODELS SHOW HIGH PRESSURE OVER THE REGION FOR THURSDAY AND FRIDAY.
FOR SATURDAY...MODELS DISAGREE WITH EACH OTHER AND CHANGE WITH EVERY
RUN. THIS DOES NOT LEAD TO A HIGH CONFIDENCE FORECAST. CURRENT
PACKAGE IS SUPPORTED BY THE CANADIAN MODEL...SO WILL STAY THE COURSE
FOR NOW UNTIL CONFIDENCE LEVELS INCREASE IN A SOLUTION.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AT THE OUTSET OF THE PERIOD FRIDAY EVENING A TROUGH WILL BE DIGGING
SOUTHWARD THROUGH THE CENTRAL CONUS...WITH POSITIVELY-TILTED AXIS
ROUGHLY FROM UPPER MID-WEST TO TEXAS. AT THE SURFACE A FRONT WILL BE
QUASI-STATIONARY TO THE NORTHWEST OF AREA OVER CENTRAL AND WESTERN
OHIO. TRIMMED BACK POPS OVER THE AREA FRI EVE WITH THIS IN MIND.
BOTH OPERATIONAL EXTENDED MODELS IS GOOD AGREEMENT WITH REGARD TO
THIS TROUGH CLOSING OFF ON ITS SOUTHERN END OVER THE SE TEXAS/LA
REGION BY SAT MORNING AND PROGRESSING THIS LOW EASTWARD ALONG THE
GULF COAST TOWARDS THE FLORIDA PANHANDLE BY EARLY SUN. GEFS MEAN
HEIGHT SOMEWHAT SURPRISINGLY KEEPS THIS LOW OPEN AND THEREFORE A BIT
MORE PROGRESSIVE...WITH ONLY FOUR OF ITS MEMBERS DEPICTING A CLOSURE
AT SUN 06Z. HOWEVER...BOTH NCEP AND EC ENSEMBLE MEAN HEIGHTS DO SHOW
THIS LOW CLOSING OFF AND THUS WILL BASE THE FORECAST ON THIS
SOLUTION.
SATURDAY THE UPPER LOW MOVING ACROSS THE GULF COAST WITH SFC
LOW...ALONG WITH A TROUGH MOVING ACROSS THE GREAT LAKES
REGION...WILL FINALLY ALLOW THE FRONT TO THE NORTHWEST TO BEGIN
PUSHING SE ACROSS THE AREA. STILL SOME DIFFERENCES IN TIMING BUT AT
THIS POINT THE FRONT IS EXPECTED TO BE AROUND THE OHIO RIVER AREA BY
18Z SAT AND NEAR THE EASTERN CWA BORDER BY 00Z SUN. LIFT AND
ABUNDANT LOW LEVEL MOISTURE STILL SUPPORT INCREASING CHANCES OF RAIN
SATURDAY AND SATURDAY EVENING. BEYOND THIS PERIOD MODELS BEGIN TO
DIVERGE WITH RESPECT TO THE DETAILS SURROUNDING CLOSED LOW AND
NORTHERN TROUGH...WITH THE GFS MORE PROGRESSIVE IN MOVING THE CLOSED
LOW NE AND INTO PHASE WITH THE DIVING NORTHERN TROUGH BY EARLY
MON...AND THE EC MUCH SLOWER IN PROGRESSION AND KEEPING THE TWO
SYSTEMS SEPARATE. NO REAL LEANING ONE WAY OR THE OTHER WHEN IT COMES
TO ENSEMBLES HERE...AND WITH NO REAL WAY TO DIFFERENTIATE AM
INCLINED TO BELIEVE THE SLOWER SOLN AS MODELS TEND TO BE MORE
PROGRESSIVE THAN REALITY WITH CLOSED SYSTEMS. THIS SOLUTION KEEPS
THE NORTHERN TROUGH DOMINANT IN ITS MOVING PRECIP EAST OF AREA
QUICKLY AFTER SUNDAY. HOWEVER...AGAIN WITH THE UNCERTAINTY I WILL
KEEP SOME MENTION OF POPS IN FOR MONDAY INTO TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
12Z WEDNESDAY TO 12Z THURSDAY...
S/W TROF MOVING THRU COMBINED WITH ISENTROPIC LIFT AND SFC WAVE
WILL PROVIDE FOR MAINLY -RA ACROSS ALONG AND EAST OF US119/I79
CORIDOR THRU 15Z BEFORE CONFINING ACROSS MTNS. GENERALLY MVFR
CIGS AND VSBY DEVELOPING ACROSS THE WV MTNS. EXCEPTION WILL ACROSS
EASTERN SLOPES WHERE SE FLOW NEAR SFC WILL ALLOW FOR IFR CIGS TDY.
ELSEWHERE...-RA MAY PUSH FURTHER W TO A KCRW TO KCKB LINE. HOWEVER
EXPECTING MAINLY VFR CONDITIONS WITH CIGS LOWERING INTO LOW END OF
RANGE AND VSBY REMAINING UNRESTRICTED. SYS SLOWLY PULLS E WITH
GRADUAL CLEARING ACROSS SE OH THIS AFTN. CLDS WILL HANG TOUGH E OF
OH RVR THRU 00Z AS LLVL MOISTURE SLOW TO DEPART. EXPECT MVFR CIGS
OVER MTNS TO LWR INTO IFR TONIGHT WITH VSBY APPROACHING IFR AS
WELL...INCLUDING KBKW. LIFR STRATUS POSSIBLE ACROSS AFTER 06Z MTN
TAF SITES.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF MVFR CIGS THIS MORNING
AND TDY. EXTENT OF -RA MAY VARY. IFR CIGS MAY EXPAND FURTHER W
FROM EASTERN SLOPES TDY TO INCLUDE KBKW. LOW STRATUS AND SOME FG MAY
DEVELOP ACROSS WV LOWLANDS TONIGHT ESPECIALLY IN AREAS THAT
RECEIVED RAINFALL.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EDT 1HRLY 07 08 09 10 11 12 13 14 15 16 17 18
CRW CONSISTENCY M M L M L L L M H H H H
HTS CONSISTENCY H H H M L L L L H H H H
BKW CONSISTENCY L L L L L L L L H H H H
EKN CONSISTENCY M M M H M H H M M H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H M M M H H M L H H H H
AFTER 12Z THURSDAY...
IFR CONDITIONS TONIGHT SOUTHWEST VIRGINIA AND THE SOUTHERN WV
MOUNTAINS.
IFR CONDITIONS POSSIBLE FRIDAY NIGHT AND SATURDAY IN CLOUDS AND
PRECIPITATION.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...50
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
324 AM EDT WED APR 18 2012
.SYNOPSIS...
A WAVE DEVELOPS AND AFFECTS MAINLY THE MOUNTAINS TODAY. HIGH
PRESSURE THURSDAY AND FRIDAY. A STORM SYSTEM FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THERE CONT TO BE SOME DISAGREEMENT WITH NW EXTENT OF MEASURABLE PCPN
THIS MORNING WITH THE NAM THE LONE GUN KEEP BULK OF QPF ACROSS THE
MTNS. MOST OTHER GUIDANCE HAS SHIFTED SOME TO NW WITH MEASURABLE
QPF...TAKING .1 TO .25 INCH CONTOUR THRU THE COAL FIELDS TO ABOUT
CRW AREA AND N UP I79 CORRIDOR. PLACEMENT OF LIFT AND FORCING
SIMILAR THOUGH. LOOKING AT MDL SOUNDINGS...ONE SEES WHERE NAM IS
HOLDING ON DRY AIR NEAR THE SFC W OF MTNS AS OTHER MDLS INCLUDING
THE RUC SATURATE THE COLUMN BY 12Z W TO CRW. LATEST RADAR MOSAIC
SHOWS SOLID AREA OF MAINLY -RA OVER SW VA AND S WV MTNS ATTM. THIS
IS TRYING TO PUSH NW SLOWLY BUT HAVING A HARD TIME GIVEN DRY AIR IN
FRONT OF IT. WILL NUDGE HIGHER POPS A HAIR NW 09-15Z THIS MORNING
BUT NOT AS MUCH AS MODEL CONSENSUS SUGGESTS WITH A BELIEF THE NAM
MAY BE HANDLING THE BL MOISTURE BETTER AS EVEN WHERE THERE IS RA OUT
THERE...NOT SEEING ANY VSBY RESTRICTIONS OR LOW CIGS CURRENTLY. WILL
CONT TO MONITOR NEXT FEW HRS FOR ANY FURTHER ADJUSTMENT TO NW.
OTHERWISE REMAINDER OF PREV FCST LOOKS GOOD. S/W TROF AXIS PUSHES
THRU THIS AFTN TAKING MUCH OF THE DEEP MOISTURE WITH IT AS SFC WAVE
PUSHES OFF TO NE. WILL GRADUALLY BRING POPS DOWN FROM W TO E THIS
AFTN...WITH AREA POP FREE BY 03Z. CONCERNING CLDS...WILL HOLD WV/SW
VA ZONES IN CLDS MUCH OF THE DAY AND ALLOW FOR SOME CLEARING ACROSS SE
OH/NE KY LATER IN AFTN. MAY SEE LOW STRATUS HOLD IN MTNS TONIGHT
WITH FG FOR ANY AREAS THAT RECEIVE RA THAT MANAGE TO CLR.
WILL LEAN TOWARD LWR NUMBERS FOR TDY GIVEN ABUNDANCE OF CLDS AND RA
ACROSS MTNS AND NUDGE TOWARD WARMER GUIDANCE ACROSS SE OH WHERE
SOME PARTIAL CLEARING MAY BE REALIZED THIS AFTN. WENT WITH WARMER
GUIDANCE FOR LOWS TONIGHT EAST OF OH RVR WITH SOME LINGERING CLDS.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MODELS SHOW HIGH PRESSURE OVER THE REGION FOR THURSDAY AND FRIDAY.
FOR SATURDAY...MODELS DISAGREE WITH EACH OTHER AND CHANGE WITH EVERY
RUN. THIS DOES NOT LEAD TO A HIGH CONFIDENCE FORECAST. CURRENT
PACKAGE IS SUPPORTED BY THE CANADIAN MODEL...SO WILL STAY THE COURSE
FOR NOW UNTIL CONFIDENCE LEVELS INCREASE IN A SOLUTION.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AT THE OUTSET OF THE PERIOD FRIDAY EVENING A TROUGH WILL BE DIGGING
SOUTHWARD THROUGH THE CENTRAL CONUS...WITH POSITIVELY-TILTED AXIS
ROUGHLY FROM UPPER MID-WEST TO TEXAS. AT THE SURFACE A FRONT WILL BE
QUASI-STATIONARY TO THE NORTHWEST OF AREA OVER CENTRAL AND WESTERN
OHIO. TRIMMED BACK POPS OVER THE AREA FRI EVE WITH THIS IN MIND.
BOTH OPERATIONAL EXTENDED MODELS IS GOOD AGREEMENT WITH REGARD TO
THIS TROUGH CLOSING OFF ON ITS SOUTHERN END OVER THE SE TEXAS/LA
REGION BY SAT MORNING AND PROGRESSING THIS LOW EASTWARD ALONG THE
GULF COAST TOWARDS THE FLORIDA PANHANDLE BY EARLY SUN. GEFS MEAN
HEIGHT SOMEWHAT SURPRISINGLY KEEPS THIS LOW OPEN AND THEREFORE A BIT
MORE PROGRESSIVE...WITH ONLY FOUR OF ITS MEMBERS DEPICTING A CLOSURE
AT SUN 06Z. HOWEVER...BOTH NCEP AND EC ENSEMBLE MEAN HEIGHTS DO SHOW
THIS LOW CLOSING OFF AND THUS WILL BASE THE FORECAST ON THIS
SOLUTION.
SATURDAY THE UPPER LOW MOVING ACROSS THE GULF COAST WITH SFC
LOW...ALONG WITH A TROUGH MOVING ACROSS THE GREAT LAKES
REGION...WILL FINALLY ALLOW THE FRONT TO THE NORTHWEST TO BEGIN
PUSHING SE ACROSS THE AREA. STILL SOME DIFFERENCES IN TIMING BUT AT
THIS POINT THE FRONT IS EXPECTED TO BE AROUND THE OHIO RIVER AREA BY
18Z SAT AND NEAR THE EASTERN CWA BORDER BY 00Z SUN. LIFT AND
ABUNDANT LOW LEVEL MOISTURE STILL SUPPORT INCREASING CHANCES OF RAIN
SATURDAY AND SATURDAY EVENING. BEYOND THIS PERIOD MODELS BEGIN TO
DIVERGE WITH RESPECT TO THE DETAILS SURROUNDING CLOSED LOW AND
NORTHERN TROUGH...WITH THE GFS MORE PROGRESSIVE IN MOVING THE CLOSED
LOW NE AND INTO PHASE WITH THE DIVING NORTHERN TROUGH BY EARLY
MON...AND THE EC MUCH SLOWER IN PROGRESSION AND KEEPING THE TWO
SYSTEMS SEPARATE. NO REAL LEANING ONE WAY OR THE OTHER WHEN IT COMES
TO ENSEMBLES HERE...AND WITH NO REAL WAY TO DIFFERENTIATE AM
INCLINED TO BELIEVE THE SLOWER SOLN AS MODELS TEND TO BE MORE
PROGRESSIVE THAN REALITY WITH CLOSED SYSTEMS. THIS SOLUTION KEEPS
THE NORTHERN TROUGH DOMINANT IN ITS MOVING PRECIP EAST OF AREA
QUICKLY AFTER SUNDAY. HOWEVER...AGAIN WITH THE UNCERTAINTY I WILL
KEEP SOME MENTION OF POPS IN FOR MONDAY INTO TUESDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
06Z WEDNESDAY TO 06Z THURSDAY...
S/W TROF MOVING THRU COMBINED WITH ISENTROPIC LIFT AND SFC WAVE
WILL PROVIDE FOR MAINLY -RA ACROSS THE MTNS THRU 18Z WITH
GENERALLY MVFR CIGS AND VSBY. EXCEPTION WILL ACROSS EASTERN SLOPES
WHERE SE FLOW NEAR SFC MAY ALLOW FOR IFR CIGS TDY. ELSEWHERE...-RA
MAY PUSH FURTHER W TO A KCRW TO KCKB LINE. HOWEVER EXPECTING
MAINLY VFR CONDITIONS WITH CIGS LOWERING INTO LOW END OF RANGE AND
VSBY REMAINING UNRESTRICTED. SYS SLOWLY PULLS E WITH GRADUAL
CLEARING ACROSS SE OH THIS AFTN. CLDS WILL HANG TOUGH E OF OH RVR
THRU 00Z AS LLVL MOISTURE SLOW TO DEPART. EXPECT MVFR CIGS OVER
MTNS TO LWR INTO IFR TONIGHT WITH VSBY APPROACHING IFR AS
WELL...INCLUDING KBKW. LIFR STRATUS POSSIBLE ACROSS EASTERN SLOPES
AFTER 06Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF MVFR CIGS THIS MORNING
AND TDY. EXTENT OF -RA MAY VARY. IFR CIGS MAY EXPAND FURTHER W
FROM EASTERN SLOPES TDY TO INCLUDE KBKW.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 04/18/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H H M M M M H H H H H
HTS CONSISTENCY H H H H H M H H H H H H
BKW CONSISTENCY M M L L L M M L L L L M
EKN CONSISTENCY H H H M M M M H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z THURSDAY...
IFR CONDITIONS TONIGHT SOUTHWEST VIRGINIA AND THE SOUTHERN WV
MOUNTAINS.
IFR CONDITIONS POSSIBLE FRIDAY NIGHT AND SATURDAY IN CLOUDS AND
PRECIPITATION.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...RPY
LONG TERM...50
AVIATION...30
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
209 AM EDT WED APR 18 2012
.SYNOPSIS...
A WAVE DEVELOPS AND AFFECTS MAINLY THE MOUNTAINS TODAY. HIGH
PRESSURE THURSDAY. A STORM SYSTEM FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
THERE CONT TO BE SOME DISAGREEMENT WITH NW EXTENT OF MEASURABLE PCPN
THIS MORNING WITH THE NAM THE LONE GUN KEEP BULK OF QPF ACROSS THE
MTNS. MOST OTHER GUIDANCE HAS SHIFTED SOME TO NW WITH MEASURABLE
QPF...TAKING .1 TO .25 INCH CONTOUR THRU THE COAL FIELDS TO ABOUT
CRW AREA AND N UP I79 CORRIDOR. PLACEMENT OF LIFT AND FORCING
SIMILAR THOUGH. LOOKING AT MDL SOUNDINGS...ONE SEES WHERE NAM IS
HOLDING ON DRY AIR NEAR THE SFC W OF MTNS AS OTHER MDLS INCLUDING
THE RUC SATURATE THE COLUMN BY 12Z W TO CRW. LATEST RADAR MOSAIC
SHOWS SOLID AREA OF MAINLY -RA OVER SW VA AND S WV MTNS ATTM. THIS
IS TRYING TO PUSH NW SLOWLY BUT HAVING A HARD TIME GIVEN DRY AIR IN
FRONT OF IT. WILL NUDGE HIGHER POPS A HAIR NW 09-15Z THIS MORNING
BUT NOT AS MUCH AS MODEL CONSENSUS SUGGESTS WITH A BELIEF THE NAM
MAY BE HANDLING THE BL MOISTURE BETTER AS EVEN WHERE THERE IS RA OUT
THERE...NOT SEEING ANY VSBY RESTRICTIONS OR LOW CIGS CURRENTLY. WILL
CONT TO MONITOR NEXT FEW HRS FOR ANY FURTHER ADJUSTMENT TO NW.
OTHERWISE REMAINDER OF PREV FCST LOOKS GOOD. S/W TROF AXIS PUSHES
THRU THIS AFTN TAKING MUCH OF THE DEEP MOISTURE WITH IT AS SFC WAVE
PUSHES OFF TO NE. WILL GRADUALLY BRING POPS DOWN FROM W TO E THIS
AFTN...WITH AREA POP FREE BY 03Z. CONCERNING CLDS...WILL HOLD WV/SW
VA ZONES IN CLDS MUCH OF THE DAY AND ALLOW FOR SOME CLRING ACROSS SE
OH/NE KY LATER IN AFTN. MAY SEE LOW STRATUS HOLD IN MTNS TONIGHT
WITH FG FOR ANY AREAS THAT RECEIVE RA THAT MANAGE TO CLR.
WILL LEAN TOWARD LWR NUMBERS FOR TDY GIVEN ABUNDANCE OF CLDS AND RA
ACROSS MTNS AND NUDGE TOWARD WARMER GUIDANCE ACROSS SE OH WHERE
SOME PARTIAL CLRING MAY BE REALIZED THIS AFTN. WENT WITH WARMER
GUIDANCE FOR LOWS TONIGHT EAST OF OH RVR WITH SOME LINGERING CLDS.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
IN GENERAL...WILL SEE ANY LINGERING PRECIPITATION ON WEDNESDAY NIGHT
MOVE OUT OF THE AREA...WITH HIGH PRESSURE TAKING OVER FOR THE
REMAINDER OF THE WORK WEEK. WITH THE SURFACE HIGH MAINLY EAST OF THE
CWA...SOUTHERLY FLOW WILL BRING A WARMING TREND THROUGH THURSDAY AND
FRIDAY.
THE 12Z NAM12 TRIES TO POP SOME DIURNAL TYPE SHOWERS ACROSS THE
MOUNTAINS THROUGH THE SHORT TERM...HOWEVER THIS WAS NOT REALLY
PRESENT IN PREVIOUS RUNS...AND NOT SEEING ANYTHING IN THE 12Z GFS TO
THIS EFFECT SO WILL LEAVE THINGS DRY UNTIL LATE IN THE DAY FRIDAY.
START TO INCREASE POPS ACROSS SE OHIO LATE FRIDAY AFTERNOON INTO THE
EVENING EVENING..AHEAD OF THE WEEKEND SYSTEM.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AT THE OUTSET OF THE PERIOD FRIDAY EVENING A TROUGH WILL BE DIGGING
SOUTHWARD THROUGH THE CENTRAL CONUS...WITH POSITIVELY-TILTED AXIS
ROUGHLY FROM UPPER MID-WEST TO TEXAS. AT THE SURFACE A FRONT WILL BE
QUASI-STATIONARY TO THE NORTHWEST OF AREA OVER CENTRAL AND WESTERN
OHIO. TRIMMED BACK POPS OVER THE AREA FRI EVE WITH THIS IN MIND.
BOTH OPERATIONAL EXTENDED MODELS IS GOOD AGREEMENT WITH REGARD TO
THIS TROUGH CLOSING OFF ON ITS SOUTHERN END OVER THE SE TEXAS/LA
REGION BY SAT MORNING AND PROGRESSING THIS LOW EASTWARD ALONG THE
GULF COAST TOWARDS THE FLORIDA PANHANDLE BY EARLY SUN. GEFS MEAN
HEIGHT SOMEWHAT SURPRISINGLY KEEPS THIS LOW OPEN AND THEREFORE A BIT
MORE PROGRESSIVE...WITH ONLY FOUR OF ITS MEMBERS DEPICTING A CLOSURE
AT SUN 06Z. HOWEVER...BOTH NCEP AND EC ENSEMBLE MEAN HEIGHTS DO SHOW
THIS LOW CLOSING OFF AND THUS WILL BASE THE FORECAST ON THIS
SOLUTION.
SATURDAY THE UPPER LOW MOVING ACROSS THE GULF COAST WITH SFC
LOW...ALONG WITH A TROUGH MOVING ACROSS THE GREAT LAKES
REGION...WILL FINALLY ALLOW THE FRONT TO THE NORTHWEST TO BEGIN
PUSHING SE ACROSS THE AREA. STILL SOME DIFFERENCES IN TIMING BUT AT
THIS POINT THE FRONT IS EXPECTED TO BE AROUND THE OHIO RIVER AREA BY
18Z SAT AND NEAR THE EASTERN CWA BORDER BY 00Z SUN. LIFT AND
ABUNDANT LOW LEVEL MOISTURE STILL SUPPORT INCREASING CHANCES OF RAIN
SATURDAY AND SATURDAY EVENING. BEYOND THIS PERIOD MODELS BEGIN TO
DIVERGE WITH RESPECT TO THE DETAILS SURROUNDING CLOSED LOW AND
NORTHERN TROUGH...WITH THE GFS MORE PROGRESSIVE IN MOVING THE CLOSED
LOW NE AND INTO PHASE WITH THE DIVING NORTHERN TROUGH BY EARLY
MON...AND THE EC MUCH SLOWER IN PROGRESSION AND KEEPING THE TWO
SYSTEMS SEPARATE. NO REAL LEANING ONE WAY OR THE OTHER WHEN IT COMES
TO ENSEMBLES HERE...AND WITH NO REAL WAY TO DIFFERENTIATE AM
INCLINED TO BELIEVE THE SLOWER SOLN AS MODELS TEND TO BE MORE
PROGRESSIVE THAN REALITY WITH CLOSED SYSTEMS. THIS SOLUTION KEEPS
THE NORTHERN TROUGH DOMINANT IN ITS MOVING PRECIP EAST OF AREA
QUICKLY AFTER SUNDAY. HOWEVER...AGAIN WITH THE UNCERTAINTY I WILL
KEEP SOME MENTION OF POPS IN FOR MONDAY INTO TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
06Z WEDNESDAY TO 06Z THURSDAY...
S/W TROF MOVING THRU COMBINED WITH ISENTROPIC LIFT AND SFC WAVE
WILL PROVIDE FOR MAINLY -RA ACROSS THE MTNS THRU 18Z WITH
GENERALLY MVFR CIGS AND VSBY. EXCEPTION WILL ACROSS EASTERN SLOPES
WHERE SE FLOW NEAR SFC MAY ALLOW FOR IFR CIGS TDY. ELSEWHERE...-RA
MAY PUSH FURTHER W TO A KCRW TO KCKB LINE. HOWEVER EXPECTING
MAINLY VFR CONDITIONS WITH CIGS LWRING INTO LOW END OF RANGE AND
VSBY REMAINING UNRESTRICTED. SYS SLOWLY PULLS E WITH GRADUAL
CLRING ACROSS SE OH THIS AFTN. CLDS WILL HANG TOUGH E OF OH RVR
THRU 00Z AS LLVL MOISTURE SLOW TO DEPART. EXPECT MVFR CIGS OVER
MTNS TO LWR INTO IFR TONIGHT WITH VSBY APPROACHING IFR AS
WELL...INCLUDING KBKW. LIFR STRATUS POSSIBLE ACROSS EASTERN SLOPES
AFTER 06Z.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE...MEDIUM.
ALTERNATE SCENARIOS: TIMING AND EXTENT OF MVFR CIGS THIS MORNING
AND TDY. EXTENT OF -RA MAY VARY. IFR CIGS MAY EXPAND FURTHER W
FROM EASTERN SLOPES TDY TO INCLUDE KBKW.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 04/18/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EDT 1HRLY 02 03 04 05 06 07 08 09 10 11 12 13
CRW CONSISTENCY H H H M M M M H H H H H
HTS CONSISTENCY H H H H H M H H H H H H
BKW CONSISTENCY M M L L L M M L L L L M
EKN CONSISTENCY H H H M M M M H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 06Z THURSDAY...
IFR CONDITIONS TONIGHTN SOUTHWEST VIRGINIA AND THE SOUTHERN WV
MOUNTAINS.
IFR CONDITIONS POSSIBLE FRIDAY NIGHT AND SATURDAY IN CLOUDS AND
PRECIPITATION.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...RPY/30
NEAR TERM...30
SHORT TERM...MZ
LONG TERM...50
AVIATION...30
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
857 PM EDT THU APR 19 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE ALONG THE EAST COAST WILL PROVIDE FAIR AND
MAINLY DRY WEATHER THROUGH FRIDAY. A FRONTAL SYSTEM IS EXPECTED
TO PASS THROUGH THE STATE ON SATURDAY AND BECOME NEARLY STATIONARY
ALONG OR JUST OFF THE EASTERN SEABOARD. A DEEP UPPER TROUGH IS
THEN EXPECTED TO DEVELOP ACROSS THE LOWER GREAT LAKES AND NORTHEAST
STATES...AND POSSIBLY BRING MORE UNSETTLED CONDITIONS TO THE
REGION EARLY NEXT WEEK.
FAIR WEATHER AND GRADUALLY MODERATING TEMPERATURES WILL FOLLOW
INTO THE MIDDLE AND LATTER PART OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
RIDGE OF HIGH PRESSURE JUST SOUTH OF PA WILL PROVIDE THE AREA WITH
FAIR AND MILD CONDS OVERNIGHT. SOUTHEAST PA...WHERE GRADIENT
WEAKEST MAY HAVE SOME FOG TOWARDS DAWN. LATEST HRRR SHOWING NR 100
PCT SFC RH ACROSS OUR SE COUNTIES LATE TONIGHT. BASED ON LATE AFTN
DWPTS...DON/T SEE TEMPS FALLING ANY FURTHER THAN THE 40S TONIGHT.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
FRIDAY LOOKS LIKE A STELLAR MID SPRING DAY AS WE WILL BE FIRMLY
IN THE WARM SECTOR OF A LOW THAT IS EXPECTED TO MOVE DOWN THE ST
LAWRENCE RIVER VALLEY. ANY FOG ACROSS THE SE COUNTIES SHOULD
DIMINISH SHORTLY AFTER SUNRISE...LEAVING A MOSTLY SUNNY AND VERY
MILD DAY. MDL 850 TEMPS SHOULD SUPPORT MAX TEMPS IN THE L/M 70S.
DID INCREASE THE CLOUD COVER SOUTHEAST OF HARRISBURG LATE IN THE
DAY. LATEST MDL DATA INDICATES INCREASINGLY MOIST SSE FLOW WILL
DRAW STRATO-CU INTO THAT AREA BY LATE AFTN.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
INCREASING CLOUDS FRI NIGHT AS FRONTAL SYSTEM APPROACHES CWA. THIS
FRONT WILL TAKE ITS TIME SLIDING THROUGH THE REGION ON SATURDAY
WITH ALL SPOTS SEEING A BRIEF PERIOD OF MOSTLY LIGHT RAIN. GFS
FASTER WITH THIS FRONT...PUSHING THE SYSTEM THRU CENTRAL PA BY
EARLY AFTERNOON. CMC AND EURO A LITTLE SLOWER WITH THE FROPA.
BEHIND THIS FRONT IS WHEN THE FORECAST BECOMES CONSIDERABLE MORE
UNCERTAIN. NORTHERN TROF WILL BRING COOL AIR TO THE CWA ON SUNDAY.
SOUTHERN STREAM SHORTWAVE OVER DEEP SOUTH BEGINS TO MOVE NE AND
ALL MODELS SHOW EVENTUAL PHASING INTO A DEEP UPPER LEVEL AND
ASSOCIATED SURFACE LOW SUNDAY NIGHT. WHERE THIS PHASING OCCURS
WILL HAVE BIG IMPACTS ON THE WEATHER ACROSS THE NE. 12Z GFS AND
MOST OF ITS ENSEMBLES SHOW THIS HAPPENING FAR ENOUGH EAST OF THE
CWA TO HAVE MINOR IMPACTS. NEWEST 12Z EURO IS MUCH CLOSER TO THE
COAST WITH THE PHASING AND SHOWS PRECIPITATION SPREADING BACK INTO
THE AREA SUNDAY NIGHT AND MONDAY. ITS COLD ENOUGH THAT SNOW OR
MIXED PRECIP IS POSSIBLE ACROSS THE HIGHER TERRAIN. WITH SUCH
SPREAD RIGHT NOW...KEPT THE FORECAST SOMEWHERE IN THE MIDDLE WITH
A MENTION OF PRECIPITATION SUNDAY NIGHT AND MONDAY. AS MODELS COME
INTO LINE WE CAN NUDGE THE FORECAST ACCORDINGLY. COOLED THE LOW
TEMPERATURES OFF AS THICKNESSES VERY LOW AND IF GFS VERIFIES WITH
CLEARER SKIES WE SHOULD SEE MORE SUBFREEZING TEMPERATURES NEXT WEEK.
&&
.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
A RIDGE OF HIGH PRESSURE ALONG THE EAST COAST WILL PROVIDE FAIR
AND DRY WEATHER THROUGH FRIDAY. VFR WILL CONTINUE THROUGH
FRIDAY...WITH JUST SOME PATCHY FOG POSSIBLE ONCE AGAIN AROUND
SUNRISE FRI. WINDS WILL REMAIN LIGHT THROUGH THE PERIOD.
OUTLOOK...
FRI NIGHT-SAT...MVFR/IFR DEVELOPING IN RAIN SHOWERS.
SUN...VFR.
MON-TUES...POSSIBLE MVFR IN RAIN OR SNOW SHOWERS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...LA CORTE
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD/LA CORTE
LONG TERM...ROSS
AVIATION...LA CORTE/GARTNER
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1253 PM CDT WED APR 18 2012
.UPDATE...
AVIATION DISCUSSION UPDATED FOR 18Z TAF ISSUANCE.
SENDING OUT A QUICK UPDATE THIS MORNING SINCE IT`S CLOUDY
OUTSIDE...AND CURRENTLY AT LEAST 3 HOURS AWAY FROM SEEING ANY
SEMBLANCE OF CLEARING...PER RUC 925HPA RH PROGS. DID NOT ADJUST
HIGH TEMPERATURES DOWN YET...AS THERE IS STILL PLENTY OF TIME FOR
TEMPERATURE RECOVERY...CURRENTLY JUST 10 TO 15 DEGREES OFF
FORECAST HIGHS.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
THE WET WEATHER PATTERN WILL CONTINUE THROUGH AT LEAST THURSDAY
FOR THE NORTHERN PLAINS.
AS OF 8Z...AN AREA OF LOW PRESSURE IS LOCATED OVER WESTERN
MINNESOTA WITH LIGHT SHOWERS ONGOING ACROSS THE I-29 CORRIDOR. THESE
SHOWERS WILL PUSH EAST OF THE CWA BY 12Z WITH GENERALLY DRY
CONDITIONS EXPECTED FOR THE REST OF THE DAY PERIOD. WITH PARTLY TO
MOSTLY SUNNY SKIES...HIGH TEMPERATURES SHOULD WARM INTO THE 50S
AND 60S. HOWEVER BY TONIGHT...ANOTHER SHORTWAVE WILL BRING A
DECENT CHANCE FOR SHOWERS TO THE REGION. WITH LIMITED INSTABILITY
OR FORCING...WILL KEEP THE PCPN MENTION AS JUST RAIN SHOWERS.
RAINFALL AMOUNTS BETWEEN A QUARTER TO A HALF INCH COULD BE
POSSIBLE WITH THIS STORM SYSTEM.
PCPN CHANCES ON THURSDAY...ARE BEGINNING TO LOOK LIKELY THEN
BEFORE. LIGHT WRAP AROUND SHOWERS COULD BE POSSIBLE DURING THE
MORNING HOURS...ESPECIALLY IN THE EASTERN CWA. BY THE AFTERNOON
HOWEVER...MODELS SEEM TO DISAGREE WITH THE STRENGTH AND PLACEMENT
OF ANOTHER SHORTWAVE TROF. AT THIS TIME...IT SEEMS AS THOUGH THIS
WAVE IS TRENDING FURTHER NORTH WITH DRY CONDITIONS POSSIBLE IN THE
SOUTHERN CWA.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
OVERALL THE MODELS REMAIN CONSISTENT THROUGH THE LONG TERM.
SLOWING FLOW SHOULD RESULT IN MORE AMPLITUDE AT LEAST FOR A TIME
LATE THIS WEEKEND INTO EARLY NEXT WEEK AS HIGH PRESSURE ALOFT
BUILDS INTO THE PLAINS. BUT FIRST A DIGGING SYSTEM ON FRIDAY NIGHT
AND SATURDAY SHOULD BRING A FEW SHOWERS TO THE REGION. AFTER THAT
IT DRIES OUT UNTIL PERHAPS LATE IN THE PERIOD AS THE FLOW AGAIN
GETS FLATTENED BY PROGRESSIVE ENERGY COMING OFF THE PACIFIC AND
INTO THE WESTERN CONUS/WESTERN CANADA.
UNDERNEATH HIGH PRESSURE ALOFT...TEMPERATURES SHOULD FAVOR ABOVE
NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AREA OF MVFR CIGS CONTINUES TO SLIDE SOUTH OVER THE AREA. THESE
CLOUDS WILL SCATTER OUT AROUND MID-AFTERNOON. VSBYS WILL BE VFR.
SCT RAIN SHOWERS WILL MOVE FROM WEST TO EAST ACROSS THE REGION THIS
EVENING AND OVERNIGHT WITH MVFR/IFR CIGS RETURNING TO ALL TAF LOCATIONS AFTER
MIDNIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...DORN
SHORT TERM...SD
LONG TERM...TDK
AVIATION...CHURCH
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1015 AM CDT WED APR 18 2012
.DISCUSSION.../ISSUED AT 1015 AM CDT/
MAIN CONCERN THIS MORNING IS THE PESKY STRATUS SINKING SOUTHWARD
ACROSS AREAS NORTH OF I90. RUC AND HRRR GUIDANCE SUGGESTS THAT THIS
SWATH OF CLOUDS WILL BE HALTED OVER THE I90 CORRIDOR AS IT SPREADS
IN MORE OF AN EASTERLY DIRECTION. LOW AND MID LEVEL DRYING THIS
AFTERNOON SHOULD BEGIN BREAKING UP THESE CLOUDS IN THE EARLY
AFTERNOON. MEANWHILE...HIGH CLOUDS AHEAD OF A DEVELOPING SYSTEM TO
OUR WEST WILL ALSO BEGIN SPREADING EASTWARD THROUGH LATE THIS
AFTERNOON. WITH THIS IN MIND...HAVE ADJUSTED SKY COVERAGE UPWARDS
THROUGH THE NEXT 12 HOURS TO FOLLOW THESE TWO FEATURES. ALSO LOWERED
HIGHS A BIT ACROSS THE NORTH WITH CLOUDY SKIES EXPECTED FOR THE
MAJORITY OF THE DAY.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
BIGGEST CHALLENGE WILL CONTINUE TO BE TIMING THE PROGRESS OF THE
1000 FOOT STRATUS LAYER NORTH OF I90 THROUGH THIS AFTERNOON. EXPECT
THIS LAYER TO PRIMARILY REMAIN NORTH OF I90 AND SPREAD EASTWARD
THROUGH THE NEXT SEVERAL HOURS. KFSD WILL BE ON THE SOUTHERN FRINGE
OF THIS LAYER AND IS LIKELY TO SEE LOW CEILINGS FOR AN HOUR OR TWO.
FOR THE ONSET OF THE TAF PERIOD...STRATUS SHOULD BEING ERODING AND
LIFTING FROM 18 TO 21Z WHILE HIGHER CLOUDS BEING BUILDING IN FROM
THE WEST. THE NEXT SYSTEM WILL SPREAD SHOWERS AND ISOLATED
THUNDERSTORMS FROM WEST TO EAST FROM 03Z/THU TO THE END OF THE TAF
PERIOD. TEMPORARY MVFR VISIBILITIES WILL BE POSSIBLE WITH
PRECIPITATION.
&&
.PREV DISCUSSION.../ISSUED AT 300 AM CDT/
SHORT WAVE MOVING THROUGH EASTERN SD AS OF 08Z WITH ASSOCIATED COLD
FRONT MOVING ACROSS SOUTHWEST MINNESOTA AND NORTHWEST IOWA. SHOWERS
ASSOCIATED WITH THIS FEATURE EAST OF I29 SHOULD EXIT CWA BY 12Z SO
WILL LEAVE FORECAST DRY TODAY. WEAK COLD AIR ADVECTION BEHIND THIS
FRONT WILL PRODUCE SLIGHTLY COOLER HIGHS TODAY...WITH THE BULK OF
THE COOLING ACROSS THE NORTHERN CWA. SHOULD SEE PLENTY OF SUNSHINE
MOST PLACES...WITH INCREASING CLOUDS AHEAD OF NEXT WAVE LATER THIS
AFTERNOON ACROSS THE WEST.
WILL SEE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WITH THIS NEXT
WAVE...WITH THE BEST CHANCE OF RAIN LATER TONIGHT INTO THURSDAY
MORNING. WILL KEEP MENTION OF CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN CWA TONIGHT CLOSER TO SURFACE FRONT WHICH WILL STALL
ACROSS NEBRASKA AND IOWA. MODELS SEEM MORE IN AGREEMENT WITH BULK OF
RAIN LIMITED TO SOUTHEAST CWA THURSDAY AFTERNOON...SO WILL TRIM THE
AFTERNOON POPS ACROSS THE NORTHWEST. WITH PLENTY OF CLOUDS AND EAST
TO NORTHEAST LOW LEVEL FLOW...WITH BE A CHILLY DAY MOST PLACES.
ANOTHER WEAK WAVE SLIDES SOUTHEAST ACROSS CWA THURSDAY NIGHT...BUT
MOISTURE WILL BE LIMITED AND WILL ONLY MENTION 20% POPS WITH THIS
FEATURE.
SHOULD DRY OUT FRIDAY BUT WILL REMAIN COOL WITH HIGHS ONLY IN THE
50S. FLOW ALOFT WILL SPREAD HIGHS CLOUDS ACROSS CWA ON FRIDAY...SO
PARTLY SUNNY AT BEST.
NORTHWEST FLOW ALOFT WILL BRING ANOTHER WAVE SOUTHEAST ACROSS CWA
LATER FRIDAY NIGHT AND SATURDAY AND COULD TRIGGER A FEW SHOWERS OVER
THE NORTHEAST HALF OF CWA AHEAD OF WEAK WARM FRONT. TEMPERATURES
WILL VARY QUITE A BIT FOR HIGHS ON SATURDAY...WITH AREAS EAST OF I29
REMAINING IN THE 50S WITH NEAR 70 ACROSS THE FAR WEST.
WARMER AIR WILL SPREAD ACROSS THE CWA SUNDAY INTO TUESDAY WITH ABOVE
NORMAL TEMPERATURES EXPECTED. THE WARMEST DAY WILL BE TUESDAY WITH
HIGHS IN THE 70S TO LOWER 80S. WILL LEAVE SUNDAY THROUGH TUESDAY DRY
WITH A CHANCE OF SHOWERS AND THUNDERSTORMS MID WEEK WITH NEXT
FRONT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
903 AM CDT WED APR 18 2012
.UPDATE...
SENDING OUT A QUICK UPDATE THIS MORNING SINCE IT`S CLOUDY
OUTSIDE...AND CURRENTLY AT LEAST 3 HOURS AWAY FROM SEEING ANY
SEMBLANCE OF CLEARING...PER RUC 925HPA RH PROGS. DID NOT ADJUST
HIGH TEMPERATURES DOWN YET...AS THERE IS STILL PLENTY OF TIME FOR
TEMPERATURE RECOVERY...CURRENTLY JUST 10 TO 15 DEGREES OFF
FORECAST HIGHS.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH FRIDAY
THE WET WEATHER PATTERN WILL CONTINUE THROUGH AT LEAST THURSDAY
FOR THE NORTHERN PLAINS.
AS OF 8Z...AN AREA OF LOW PRESSURE IS LOCATED OVER WESTERN
MINNESOTA WITH LIGHT SHOWERS ONGOING ACROSS THE I-29 CORRIDOR. THESE
SHOWERS WILL PUSH EAST OF THE CWA BY 12Z WITH GENERALLY DRY
CONDITIONS EXPECTED FOR THE REST OF THE DAY PERIOD. WITH PARTLY TO
MOSTLY SUNNY SKIES...HIGH TEMPERATURES SHOULD WARM INTO THE 50S
AND 60S. HOWEVER BY TONIGHT...ANOTHER SHORTWAVE WILL BRING A
DECENT CHANCE FOR SHOWERS TO THE REGION. WITH LIMITED INSTABILITY
OR FORCING...WILL KEEP THE PCPN MENTION AS JUST RAIN SHOWERS.
RAINFALL AMOUNTS BETWEEN A QUARTER TO A HALF INCH COULD BE
POSSIBLE WITH THIS STORM SYSTEM.
PCPN CHANCES ON THURSDAY...ARE BEGINNING TO LOOK LIKELY THEN
BEFORE. LIGHT WRAP AROUND SHOWERS COULD BE POSSIBLE DURING THE
MORNING HOURS...ESPECIALLY IN THE EASTERN CWA. BY THE AFTERNOON
HOWEVER...MODELS SEEM TO DISAGREE WITH THE STRENGTH AND PLACEMENT
OF ANOTHER SHORTWAVE TROF. AT THIS TIME...IT SEEMS AS THOUGH THIS
WAVE IS TRENDING FURTHER NORTH WITH DRY CONDITIONS POSSIBLE IN THE
SOUTHERN CWA.
.LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
OVERALL THE MODELS REMAIN CONSISTENT THROUGH THE LONG TERM.
SLOWING FLOW SHOULD RESULT IN MORE AMPLITUDE AT LEAST FOR A TIME
LATE THIS WEEKEND INTO EARLY NEXT WEEK AS HIGH PRESSURE ALOFT
BUILDS INTO THE PLAINS. BUT FIRST A DIGGING SYSTEM ON FRIDAY NIGHT
AND SATURDAY SHOULD BRING A FEW SHOWERS TO THE REGION. AFTER THAT
IT DRIES OUT UNTIL PERHAPS LATE IN THE PERIOD AS THE FLOW AGAIN
GETS FLATTENED BY PROGRESSIVE ENERGY COMING OFF THE PACIFIC AND
INTO THE WESTERN CONUS/WESTERN CANADA.
UNDERNEATH HIGH PRESSURE ALOFT...TEMPERATURES SHOULD FAVOR ABOVE
NORMAL THROUGH THE PERIOD.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A BATCH OF MVFR CIGS IS ADVECTING SOUTH OVER THE AREA AND MAY
REMAIN AROUND THROUGH THE NOON HOUR BEFORE MIXING OUT. VSBYS
SHOULD BE GENERALLY VFR EXCEPT FOR PATCHY MVFR DUE TO FOG. RAIN
WILL MOVE FROM WEST TO EAST ACROSS THE REGION THIS EVENING AND
OVERNIGHT WITH IFR CIGS POSSIBLE AFTER MIDNIGHT.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...DORN
SHORT TERM...SD
LONG TERM...TDK
AVIATION...TDK
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
615 AM CDT WED APR 18 2012
.DISCUSSION.../ISSUED AT 300 AM CDT/
SHORT WAVE MOVING THROUGH EASTERN SD AS OF 08Z WITH ASSOCIATED COLD
FRONT MOVING ACROSS SOUTHWEST MINNESOTA AND NORTHWEST IOWA. SHOWERS
ASSOCIATED WITH THIS FEATURE EAST OF I29 SHOULD EXIT CWA BY 12Z SO
WILL LEAVE FORECAST DRY TODAY. WEAK COLD AIR ADVECTION BEHIND THIS
FRONT WILL PRODUCE SLIGHTLY COOLER HIGHS TODAY...WITH THE BULK OF
THE COOLING ACROSS THE NORTHERN CWA. SHOULD SEE PLENTY OF SUNSHINE
MOST PLACES...WITH INCREASING CLOUDS AHEAD OF NEXT WAVE LATER THIS
AFTERNOON ACROSS THE WEST.
WILL SEE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WITH THIS NEXT
WAVE...WITH THE BEST CHANCE OF RAIN LATER TONIGHT INTO THURSDAY
MORNING. WILL KEEP MENTION OF CHANCE OF THUNDERSTORMS ACROSS
SOUTHERN CWA TONIGHT CLOSER TO SURFACE FRONT WHICH WILL STALL
ACROSS NEBRASKA AND IOWA. MODELS SEEM MORE IN AGREEMENT WITH BULK OF
RAIN LIMITED TO SOUTHEAST CWA THURSDAY AFTERNOON...SO WILL TRIM THE
AFTERNOON POPS ACROSS THE NORTHWEST. WITH PLENTY OF CLOUDS AND EAST
TO NORTHEAST LOW LEVEL FLOW...WITH BE A CHILLY DAY MOST PLACES.
ANOTHER WEAK WAVE SLIDES SOUTHEAST ACROSS CWA THURSDAY NIGHT...BUT
MOISTURE WILL BE LIMITED AND WILL ONLY MENTION 20% POPS WITH THIS
FEATURE.
SHOULD DRY OUT FRIDAY BUT WILL REMAIN COOL WITH HIGHS ONLY IN THE
50S. FLOW ALOFT WILL SPREAD HIGHS CLOUDS ACROSS CWA ON FRIDAY...SO
PARTLY SUNNY AT BEST.
NORTHWEST FLOW ALOFT WILL BRING ANOTHER WAVE SOUTHEAST ACROSS CWA
LATER FRIDAY NIGHT AND SATURDAY AND COULD TRIGGER A FEW SHOWERS OVER
THE NORTHEAST HALF OF CWA AHEAD OF WEAK WARM FRONT. TEMPERATURES
WILL VARY QUITE A BIT FOR HIGHS ON SATURDAY...WITH AREAS EAST OF I29
REMAINING IN THE 50S WITH NEAR 70 ACROSS THE FAR WEST.
WARMER AIR WILL SPREAD ACROSS THE CWA SUNDAY INTO TUESDAY WITH ABOVE
NORMAL TEMPERATURES EXPECTED. THE WARMEST DAY WILL BE TUESDAY WITH
HIGHS IN THE 70S TO LOWER 80S. WILL LEAVE SUNDAY THROUGH TUESDAY DRY
WITH A CHANCE OF SHOWERS AND THUNDERSTORMS MID WEEK WITH NEXT
FRONT.
&&
.AVIATION.../FOR THE 12Z TAF ISSUANCE/
BIGGEST CHALLENGE THIS MORNING WILL BE UNCERTAINTY REGARDING STRATUS
COVERAGE. STRATUS HAS DEVELOPED ACROSS NORTH DAKOTA AND NORTH
CENTRAL SOUTH DAKOTA EARLY THIS MORNING...AND LOOKING TO BE HEADED
TO THE SOUTH. MODELS NOT HANDLING IT VERY WELL...THOUGH RUC HINTING
AT IT MAKING INTO THE HURON AREA DURING THE MORNING HOURS. QUESTION
THEN BECOMES HOW LONG IT WILL HANG OVER THE AREA AND HOW FAR SOUTH
IT WILL MAKE IT. AT THIS POINT...INCLUDE IN KHON TAF THROUGH
15Z...AND KEPT IT OUT OF KFSD...THOUGH UNCERTAINTY FAIRLY HIGH.
AFTER ANY STRATUS DISSIPATES LATER IN THE MORNING EXPECT VFR
CONDITIONS INTO THIS EVENING...BEFORE THE NEXT SYSTEM BRINGS SHOWERS
INTO THE AREA AFTER 03Z TONIGHT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
913 PM CDT THU APR 19 2012
.UPDATE...
DUE TO THE NEARLY DRY ADIABATIC LAPSE RATES AND THE STRONG FORCING
THAT WILL BE OVERSPREADING THE REGION FROM THE NORTHWEST
TONIGHT...THE CONVECTIVE FORECAST IS HIGHLY SENSITIVE TO THE
AMOUNT OF MOISTURE AVAILABLE IN THE MID LEVELS...SPECIFICALLY
MOISTURE NEAR 700 MB. THE 00Z SOUNDING DATA FROM AROUND THE REGION
SHOWED THE MID LEVELS TOO DRY FOR CONVECTION AT FWD/DRT/MAF...BUT
INDICATED AMPLE MOISTURE AT AMA. TONIGHT/S FORECAST WOULD BE EASIER
IF WE HAD ANOTHER SOUNDING NEAR ABILENE...BUT WE DO NOT...SO WE
WILL HAVE TO INFER THAT GIVEN THE EXTENSIVE ACCUS FIELD THAT
DEVELOPED EARLIER...THAT THE MOISTURE IS AVAILABLE. THE RUC IS
PARTICULARLY AGGRESSIVE WITH INDICATING A POCKET OF MOISTURE FROM
SJT-ABI-SPS THAT WILL MOVE EASTWARD INTO THE WESTERN AND CENTRAL
ZONES LATER TONIGHT. THIS SOLUTION IS ALSO SUPPORTED BY THE HRRR.
THUS I THINK THERE ARE ENOUGH INDICATIONS THAT THIS POCKET OF
700MB MOISTURE DOES EXIST...AND AS IT ARRIVES INTO THE AREA LATER
TONIGHT...SHOULD RESULT IN AN INCREASE IN ELEVATED SHOWERS AND
STORMS ACROSS THE WESTERN ZONES. ACTIVITY SHOULD SPREAD EAST INTO
THE CENTRAL ZONES EARLY FRIDAY MORNING. HAVE INCREASED POPS TO
30-40 PERCENT ACROSS THE WESTERN AND CENTRAL ZONES. MARGINALLY
SEVERE HAIL WILL BE POSSIBLE WITH THE STRONGEST CELLS.
OTHERWISE...SMALL LINE SEGMENT OF STRONG/SEVERE CONVECTION OVER
THE NW ZONES WILL CONTINUE TO TRACK EAST ACROSS THE NORTHERN TWO
ROWS OF COUNTIES THROUGH THE LATE EVENING HOURS. AGAIN MARGINALLY
SEVERE HAIL IS THE MAIN THREAT WITH THESE ELEVATED STORMS...BUT
SUB CLOUD EVAPORATION MAY PROMOTE A LOW WIND THREAT AS WELL.
TR.92
&&
.AVIATION...
A COLD FRONT STRETCHED FROM THE CENTRAL PLAINS SOUTHWESTWARD TO A
1003 MB SURFACE LOW JUST WEST OF WICHITA FALLS...THEN WEST THROUGH
THE SOUTHERN TEXAS PANHANDLE. A DRYLINE EXTENDED FROM THE LOW
CENTER INTO SOUTHWEST TEXAS LATE THIS AFTERNOON. SHOWERS AND
STORMS WILL DEVELOP MAINLY NORTH OF THE RED RIVER ALONG THE FRONT
THIS EVENING AS AN UPPER TROUGH CONTINUES TO DIG SOUTHEASTWARD
THROUGH THE CENTRAL PLAINS. ACTIVITY SHOULD REMAIN NORTH OF THE
REGION THROUGH MOST OF THE NIGHT...THEN BEGIN TO AFFECT TAF SITES
AS THE FRONT MOVES INTO THE AREA EARLY TOMORROW MORNING.
SOME WARM ADVECTION SHOWERS MAY OCCUR AHEAD OF THE FRONT SO WILL
STICK WITH THE VCSH BEGINNING AROUND 10Z. THUNDERSTORMS ARE
POSSIBLE DUE MAINLY TO FORCING ALONG THE FRONT...BUT WITH THE
LIMITED MOISTURE AND INSTABILITY THE THREAT LOOKS RELATIVELY LOW.
WILL KEEP THE PREVAILING SHRA FOR THE MORNING HOURS BEGINNING AT
13Z IN THE METROPLEX...AND 15Z IN WACO...WHICH COINCIDES WITH
FROPA TIMING. IF FUTURE TRENDS OR LATER GUIDANCE POINT TOWARDS
MORE WIDESPREAD CONVECTION...WILL ADJUST 06Z TAFS ACCORDINGLY.
NORTH WINDS WILL BECOME A BIT GUSTY TOMORROW AFTERNOON. MVFR CIGS
ARE EXPECTED DURING THE MORNING AND EARLY AFTERNOON HOURS BUT
SHOULD GIVE WAY TO VFR CONDITIONS BY THIS TIME FRIDAY.
30
&&
.PREV UPDATE...
.UPDATE...
STRONG UPPER LEVEL DISTURBANCE APPROACHING FROM THE WEST COMBINED
WITH STEEP LAPSE RATES ALOFT AND SUFFICIENT MID LEVEL MOISTURE
WILL ALLOW FOR PRIMARILY ELEVATED CONVECTION TO AFFECT THE
NORTHWESTERN ZONES THIS EVENING. INSTABILITY AND CLOUD LAYER SHEAR
WILL BE SUFFICIENT FOR A SEVERE HAIL THREAT. SPC HAS JUST ISSUED
A SEVERE THUNDERSTORM WATCH FOR THE NW PARTS OF THE CWA. IT IS
POSSIBLE A LINE SEGMENT WILL ORGANIZE FROM THE EARLY EVENING
ACTIVITY AND TRACK EASTWARD THROUGH THE NORTHERN ZONES DURING THE
LATE EVENING HOURS...BUT ELEVATED NATURE OF STORMS MAY LIMIT THE
ABILITY FOR CONVECTION TO GROW UPSCALE INTO A MCS.
REGARDLESS...GIVEN THE AMPLE ELEVATED INSTABILITY...BELIEVE AT
LEAST SCATTERED CONVECTION SHOULD SUSTAIN ITSELF LONG ENOUGH TO
AFFECT THE NORTHEAST ZONES AFTER MIDNIGHT.
HAVE UPDATED FORECAST TO BUMP UP POPS THIS EVENING IN THE NW
ZONES. WILL AWAIT 00Z SOUNDING DATA TO DETERMINE IF POPS NEED TO
BE RAISED ALONG AND/OR SOUTH OF THE I-20 CORRIDOR.
TR.92
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT THU APR 19 2012/
THE NEXT 24 HOURS APPEAR TO BE THE MOST ACTIVE OVER THE NEXT 7
DAYS. THIS AFTERNOON A COLD FRONT EXTENDS ACROSS CENTRAL KANSAS
INTO WESTERN OKLAHOMA AND INTO THE TEXAS PANHANDLE. A DRYLINE IS
LOCATED ALONG A LINE FROM A SURFACE LOW NEAR CHILDRESS TO BIG
SPRING AND INTO THE BIG BEND REGION. A S/W TROF CURRENTLY DIGGING
ACROSS MONTANA AND WYOMING WILL DEEPEN OVER THE NEXT 12 HOURS IN
RESPONSE TO UPSTREAM RIDGE AMPLIFICATION OVER THE WEST COAST.
LATER TONIGHT...THE COLD FRONT WILL SLIDE FARTHER SOUTH AS MAIN
SURFACE LOW OVER THE MIDWEST CONTINUES NORTHEAST. THE ATMOSPHERE
ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA IS UNSTABLE HOWEVER IT
REMAINS STRONGLY CAPPED TO SURFACE BASED CONVECTION AND IS
EXPECTED TO REMAIN SO FOR MUCH OF THE EVENING. AS HEIGHT
FALLS/LARGE SCALE FORCING FOR ASCENT CONTINUES TO OVERSPREAD THE
SOUTHERN PLAINS TONIGHT...FORCING ALONG THE FRONT IS EXPECTED TO
INCREASE AND BECOME SUFFICIENT FOR THUNDERSTORMS TO DEVELOP
PRIMARILY ACROSS THE FAR NORTHWEST COUNTIES. FORECAST SOUNDINGS
ACROSS NORTHWEST PORTIONS OF THE CWA INDICATE THAT PARCELS FORCED
BETWEEN 800-700MB WILL HAVE LITTLE INHIBITION BETWEEN 10 PM AND
MIDNIGHT. SHEAR PROFILES WILL SUPPORT SUPERCELL STRUCTURES WITH
ANY STORMS THAT CAN DEVELOP DURING THIS TIME...HOWEVER THE PRIMARY
SEVERE WEATHER THREAT WILL BE LARGE HAIL GIVEN THE NEARLY DRY
ADIABATIC MID LEVEL LAPSE RATES AND HIGH LCL/S. FARTHER SOUTH NEAR
THE METROPLEX...STRONG INHIBITION WILL LIKELY REMAIN IN PLACE AND
CONVECTION WILL LIKELY HAVE TO WAIT ON THE FRONT. WILL HAVE THE
HIGHEST POPS RIGHT ALONG THE RED RIVER TAPERING OFF QUICKLY TO THE
SOUTH FOR TONIGHT.
COLD FRONT WILL MOVE THROUGH NORTH TEXAS TOMORROW MORNING WITH
CAPPING ERODING BY THIS TIME. SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED RIGHT ALONG AND BEHIND THE FRONT. BEST CHANCES WILL
BE ACROSS THE NORTHEAST AND EAST DURING THE MORNING...THEN SHIFT
TO THE SOUTHEAST COUNTIES BY EARLY AFTERNOON AS THE FRONT
PROGRESSES SOUTHWARD. RAIN AND THUNDERSTORMS WILL CLEAR THE CWA BY
TOMORROW EVENING WITH HIGH PRESSURE BUILDING IN AND COOLER
TEMPERATURES EXPECTED. HIGHS ON SATURDAY WILL ONLY BE IN THE LOW
70S WITH LOWS IN THE MID TO UPPER 40S.
THE WEEKEND AND MUCH OF NEXT WEEK LOOKS VERY QUIET WITH LITTLE
CHANCE FOR RAIN AND PLEASANT TEMPERATURES. MID LEVEL RIDGING LOOKS
LIKE IT WILL REMAIN IN PLACE FOR SEVERAL DAYS. THE GFS DOES INDICATE
AN AXIS OF MOISTURE AND INSTABILITY WORKING NORTH INTO THE SOUTHERN
PLAINS BY MIDWEEK WITH MODERATE NORTHWEST FLOW ALOFT. AT THIS TIME
SEE NO SIGNIFICANT SYSTEM THAT WILL BE SUFFICIENT TO INITIATE
CONVECTION BUT WILL CONTINUE TO MONITOR.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 60 70 47 71 50 / 30 60 5 0 0
WACO, TX 62 71 45 73 44 / 20 50 5 0 0
PARIS, TX 58 66 46 69 47 / 50 60 10 0 0
DENTON, TX 58 67 45 69 48 / 40 50 5 0 0
MCKINNEY, TX 60 68 46 70 48 / 40 60 5 0 0
DALLAS, TX 61 70 47 71 50 / 30 60 5 0 0
TERRELL, TX 60 69 45 72 46 / 20 60 5 0 0
CORSICANA, TX 62 71 47 73 48 / 20 60 10 0 0
TEMPLE, TX 62 74 46 74 46 / 20 50 10 0 0
MINERAL WELLS, TX 58 70 44 72 46 / 40 40 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
/
AREA FORECAST DISCUSSION
NWS SPOKANE WA
855 PM PDT Thu Apr 19 2012
.SYNOPSIS...
Widespread light rain will overspread the region tonight...with
unsettled...breezy and showery conditions lingering through
Friday. Warmer than average temperatures are expected over the
weekend with mostly dry conditions Saturday but with the
possibility of afternoon thunderstorms by Sunday and Monday. A
return to more seasonal temperatures is expected as a cold front
arrives Tuesday.
&&
.DISCUSSION...
Evening Update: A very moist storm system is bearing down on
the Inland NW with a 1.2" precipitable water fetch slamming into
the coast and warm sector rain already observed or soon to be
observed at most observations. The heaviest rainfall as of 830PM
was noted across the central Columbia Basin along the leading warm
front where we are observing rainfall rates of 0.02-0.05"/hour.
The 02z RUC appeared to capture this enhanced pcpn well on its
295K isentropic charts which in conjunction with the latest radar
loop will continue to expand and march toward the Idaho Panhandle
well before 06z. As such, forecast PoPs have been raised into the
80-100% range with QPF amts incr near a tenth across the eastern
Columbia Basin...Palouse...and West Plains. Behind the warm front,
there is some midlevel drying and backing of winds more to the sw
from s allowing a pseudo rain shadow in the lee of the central
Cascades and Wenatchee area and despite the continued rain
falling, ceilings have been on the rise during the last few hours.
This shadow will continue to incr overnight as pressure falls
strengthen over southern Alberta we incr the westerly component to
midlevel flow...however with the main surface low driving this
moisture and frontal structures into the region lifting northward
along the central BC coast...the main cool occlusion never really
dips south of highway 2 and basically gets hung up across the
region in a sw to ne fashion leading to low confidence that
communities in the lee of the Cascades will remain completely dry.
There is strong agreement that the incr west/southwest flow will
lead to a very wet 6-12z period for the Idaho Panhandle and far
eastern reaches of WA due to enhanced upsloping component. As
such, I have trend QPF amts and PoPs upward. The good news is that
we remain in a relative warm sector through much of the event and
we are not expecting surprising convective bands capable of the
1.00" or greater QPF amts were saw with a flooding event over the
Palouse on March 25/26. On that same note, snow levels which are
roughly 5K north to 6-7K ft south are expected to continue to rise
enhancing snowmelt processes...which will lead to rises across
most basins; especially the St Joe where an RVS has been issued.
/sb
&&
.AVIATION...
00Z TAFs: A very moist storm system is making its way into the
region with top-down saturation in progress and additional
lowering of cigs likely through the evening. MVFR/IFR cigs
expected for KPUW/KGEG/KSFF/KCOE with the onset of heavier pcpn
aft 05z and persisting through 18z even as pcpn wanes roughly
12z due to moist upsloping component to low-level winds. Confidence
much lower for KEAT/KMWH/KLWS that cigs will dip below 5k ft
but enhanced pcpn may result in an overly optimistic fcst and did
introduce sct035 for KEAT. Strengthening low pressure east of the
Divide aft 12z will incr sw pressure gradients yielding continued
upsloping -shra along the ID/WA border and potential for strong
to gusty winds sustained 12-19kts with gusts 22-28kts. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 43 61 43 65 44 75 / 90 50 20 10 0 10
Coeur d`Alene 43 61 42 65 41 75 / 100 60 20 10 10 10
Pullman 43 62 45 66 42 76 / 90 60 30 20 10 10
Lewiston 48 69 50 73 48 81 / 100 30 20 10 10 10
Colville 42 65 40 67 41 77 / 100 70 10 0 0 0
Sandpoint 42 61 40 62 39 72 / 100 90 20 10 10 10
Kellogg 41 58 42 63 42 73 / 100 90 50 20 10 10
Moses Lake 45 68 43 71 45 79 / 100 10 0 0 0 10
Wenatchee 46 67 45 69 48 76 / 70 10 0 0 0 10
Omak 42 68 35 69 41 77 / 70 10 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1100 PM CDT THU APR 19 2012
.SHORT TERM...TONIGHT
845 PM CDT THU APR 19 2012
RADAR TRENDS AND LATEST RUNS OF THE MESO HRRR MODEL POINT TO AN
EARLIER EXIT EAST OF THE BROAD AREA OF PCPN ACROSS THE REGION. THERE
HAS BEEN SOME MIX OF RAIN/SNOW NORTH OF I-94...MORE SO INTO
NORTHEAST WI. WITH THE QUICKER EXIT THOUGH...THERE WILL BE LESS TIME
TO SWITCH TO SNOW...THUS LOWER QPF AND LOWER SNOW ACCUM POTENTIAL.
HAVE ACCELERATED THE EXIT OF THE PCPN CHANCES TO THE EAST AS A
RESULT...AND LOWERED THE SNOW ACCUMULATIONS. THERE COULD STILL BE
SOME SCATTERED TO ISOLATED SHOWERS POST THIS MAIN PCPN SHIELD...BUT
ACCUMS OF RAIN OR SNOW WITH THESE LOOK TO BE MINIMAL.
.LONG TERM...MONDAY THROUGH THURSDAY
305 PM CDT THU APR 19 2012
19.12 FORECAST MODELS IN REASONABLE AGREEMENT ON MONDAY...THEN START
TO DIVERGE TUESDAY NIGHT THROUGH THURSDAY. NORTHWEST FLOW ALOFT IF
EXPECTED ACROSS THE FORECAST AREA THROUGH AT LEAST WEDNESDAY AS A
BROAD UPPER RIDGE REMAINS IN PLACE ACROSS THE WESTERN CONUS.
FORECAST MODELS ARE HAVING SOME ISSUES HANDLING EMBEDDED FAST-MOVING
SHORTWAVE TROUGHS IN THE NORTHWEST FLOW. THE FIRST WAVE LOOKS TO
MOVE ACROSS THE FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY AS A WARM
FRONT PUSHES ACROSS THE REGION. THE FRONT WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE UPPER MISSISSIPPI RIVER VALLEY AS
IT MOVES THROUGH. PLAN ON WARMER TEMPERATURES ON WEDNESDAY WITH
HIGHS RANGING FROM THE MID 60S ACROSS NORTH CENTRAL WISCONSIN TO THE
MID 70S ACROSS NORTHEAST IOWA. ANOTHER SHORTWAVE IS EXPECTED TO PUSH
ACROSS THE AREA ON THURSDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS
AND THUNDERSTORMS.
&&
.AVIATION...
1100 PM CDT THU APR 19 2012
THE MAIN AREA OF RAIN WAS ALREADY EAST OF KRST AND WILL BE EAST OF
KLSE BEFORE 06Z. SOME LIGHT RAIN HAS DEVELOPED ON THE BACKSIDE OF
THIS LARGER RAIN SHIELD THOUGH...BUT VSBYS HAVE TRENDED TOWARD P6SM.
KRST/KLSE WILL HAVE TO DEAL WITH THIS THROUGH ABOUT 09-10Z.
LOW CIGS SHOULD GIVE WAY TO VFR CONDITIONS BETWEEN 14-16Z...WITH
THESE CONDITIONS PERSISTING THROUGH FRIDAY NIGHT. WINDS WILL STAY UP
THROUGH THE OVERNIGHT AS THE TIGHT PRESSURE GRADIENT WITH THE
EXITING LOW PRESSURE SYSTEM REMAINS. EVENTUAL SUNSHINE ON FRIDAY
WILL PROMOTE MIXING AND LIKELY SOME GUSTINESS FROM LATE MORNING
THROUGH THE AFTERNOON. LOOK FOR LIGHTER WINDS FRIDAY NIGHT WITH
DECOUPLING AND AN AREA OF HIGH PRESSURE BUILDING IN FROM THE WEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 PM CDT THU APR 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1045 PM CDT THU APR 19 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.UPDATE...PCPN INTENSITY...LIKELY THE MELTING OF BIG WET
SNOWFLAKES...OBVIOUSLY PLAYING A ROLE IN COOLING LOW-LEVELS
ENOUGH TO ALLOW SNOW REACH THE GROUND. LIQUID PCPN STILL OCCURRING
WHERE INTENSITIES WERE LIGHTER ON THE NW FLANK OF THE PCPN
SHIELD. HAVE TO ADMIT TO BEING SURPRISED WE GOT AS MUCH COOLING AS
WE DID GIVEN THE WARM SFC WET-BULB TEMPS AT THE START OF THE EVENT.
THE SRN EDGE OF THE RN/SN LINE NOW COMING MORE INTO ALIGNMENT
WITH THE ZERO DEGREE ISOTHERM ALOFT. SO THINK WE ARE LIKELY TO
SEE A MORE GRADUAL SWD SHIFT IN THE SNOW AREA THE REST OF THE NGT.
DON/T EXPECT MUCH IN THE WAY OF ACCUMS IN AREAS WHERE SNOW ISN/T
FALLING BY NOW.
LOOKING AT HOW QUICKLY PCPN IS DIMINISHING OUT TO THE WEST...
PROBABLY COULD HAVE ENDED WRN PART OF ADVISORY EVEN SOONER THAN
THE ADJUSTED 4 AM TIME I WENT WITH LAST HOUR/S UPDATE. BUT THAT
SHOULD BE AT LEAST A BETTER APPROXIMATION THAN PREVIOUS 7 AM
EXPIRATION. BASED ON SNOWFALL CRITERIA ALONE MAY NOT HAVE NEEDED
ADVISORY AT ALL FOR WOOD/PORTAGE AND MAYBE EVEN MARATHON. BUT STARTED
GETTING REPORTS OF TRAVEL ISSUES DUE TO SLUSH ON THE ROADS...SO
KEEPING ADVISORY SEEMED THE BEST WAY TO GO EVEN IF MANY LOCATIONS
IN THE SW CORNER OF THE FCST AREA DON/T MEET CRITERIA.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 839 PM CDT THU APR 19 2012...
UPDATE...WL TWEAK THE ADVISORY. MAIN CHG WL BE TO DROP IT SOONER
BACK IN CENTRAL WI...AS PCPN PULLING OUT MORE QUICKLY. TOYED WITH
PULLING PORTAGE...AS DON/T THINK MOST OF THE COUNTY WL GET MUCH
SNOW. BUT IN THE END DECIDED TO JUST KEEP IT IN AND SPECIFY TOTALS
WL BE MAINLY NW OF STE.
NEED TO ADJUST SOME SNOW ACCUM GRIDS AND WX GRIDS LATER TNGT.
UPDATED FCST SUITE WL BE OUT ASAP.
SKOWRONSKI
DISCUSSION ISSUED AT 531 PM CDT THU APR 19 2012...
UPDATE...TRICKY FCST TNGT. RAIN EXPECTED TO CHG TO SNOW ON THE NW
FLANK OF SML BUT FAIRLY INTENSE CYCLONE TRACKING TOWARD THE AREA.
SYSTEM SHOULD REMAIN AN OPEN WAVE...SO THE HEAVIEST PCPN WL FALL
AS THE SFC LOW APPROACHES WITH A SHARP DECR IN INTENSITY ONCE IT
CROSSES JUST S OF THE AREA AND STARTS TO HEAD OFF TO THE E.
CERTAINLY GOING TO GET ENOUGH PCPN TO PRODUCE WARNING CRITERIA
SNOWS...IF IT WAS ALL OR MOSTLY SNOW. PROBLEM IS THE CHANGEOVER.
HAVE WORKED THESE LATE SEASON EVENTS IN THE PAST...AND THE ONE
THING THAT BOTHERS ME RIGHT NOW IS THAT SFC/LOW-LEVEL WET-BULB
TEMPS ARE ALL WELL ABV FZG. MODELS INSIST LOW-LEVEL TEMPS WL COOL
OVERNIGHT...BUT HAVING WET-BULB TEMPS ABV FZG WL LIMIT THE HELP FM
EVAPORATIVE COOLING WHICH CAN OFTEN HELP GET THE CHANGEOVER GOING
AT THIS TIME OF YEAR. MELTING OF THE FALLING SNOW WL PROVIDE SOME
COOLING...BUT CAN/T LOSE TOO MUCH OF THE EVENT TO LIQUID IF FCST
SNOWFALL TOTALS ARE TO WORK OUT.
GOING FCST OKAY FOR NOW...WL CONT TO MONITOR AND PROBABLY MAKE
SOME ADJUSTMENTS LATER THIS EVENING.
RECEIVED ONE REPORT THUS FAR OF A MIX. THAT WAS FM OUT IN WAUPACA
COUNTY ABOUT AN HR AGO. RADAR RETURNS AND RUC MODEL SOUNDINGS
SUGGEST THAT WAS PROBABLY SLEET.
SKOWRONSKI
DISCUSSION ISSUED AT 339 PM CDT THU APR 19 2012...
SHORT TERM...TONIGHT AND FRIDAY. POTENTIAL FOR SIGNIFICANT
SNOWFALL IS THE MAIN CONCERN FOR TONIGHT. THE MODELS...BASED ON
TIME/HEIGHT SECTIONS...HAD SOME SUBSTANTIAL DIFFERENCES IN THEIR
PRECIPITATION TYPE FORECASTS. THE 09Z SREF HAD 0.87 INCHES LIQUID
EQUIVALENT OF SNOW STARTING AROUND 00Z AT RHI WHILE THE 12Z NAM
KEPT IT ALL RAIN WITH ONLY 0.04 TOTAL QPF.
LOW PRESSURE CENTERED AROUND NORTHWEST MISSOURI AT 20Z...IS
FORECAST TO PUSH NORTHEAST AND CROSS SOUTHERN LOWER MICHIGAN ON
FRIDAY. STRONG COLD ADVECTION IS EXPECTED TO CHANGE THE
PRECIPITATION TO SNOW. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF AN UPPER LEVEL JET MAX...ALONG WITH MID LEVEL
SHORT WAVE ENERGY WILL ACT WITH THE LOW TO PRODUCE PLENTY OF
PRECIPITATION. THERE IS ENOUGH MOISTURE ASSOCIATED WITH THE
SYSTEM TO SPREAD WARNING CRITERIA SNOW ACROSS A LARGE PART OF THE
AREA...BUT MUCH OF THE PRECIPITATION WILL HAVE FALLEN BEFORE TEMPERATURES
BECOME COOL ENOUGH FOR SNOW...ESPECIALLY IN THE SOUTHEAST PART OF
THE FORECAST AREA. HAVE KEPT TOTALS IN THE HIGHEST SWATH OF SNOW
BELOW WARNING CRITERIA AS A RESULT OF THIS.
ENDED UP GOING WITH...OR AT LEAST CLOSE TO...THE HPC WINTER
WEATHER ACCUMULATION TOTALS. HAVE OPTED TO KEEP THE ADVISORY AND
ADD WOOD AND PORTAGE COUNTIES FOR HIGHER AMOUNTS IN THE NORTHERN
PARTS OF THOSE COUNTIES.
THE SYSTEM SHOULD MOVE FAIRLY QUICKLY SO ONLY HELD ONTO SOME
CHANCE POPS EARLY FRIDAY MORNING. THIS FORECAST MAY REQUIRE MAJOR
SURGERY SO STAY TUNED FOR FURTHER UPDATES.
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
ZONAL FLOW EARLY IN PERIOD...WILL BECOME AMPLIFIED BY END OF
WEEKEND WITH TROF OVER EASTERN STATES AND OFF WEST COAST AND
RIDGE IN BETWEEN. TEMPERATURES WILL START OUT AT OR SLIGHTLY
BELOW NORMAL AND THEN SHOULD TRANSITION TO ABOVE NORMAL LEVELS BY
THE END OF NEXT WEEK AS UPPER RIDGE SHIFTS EASTWARD.
MID RANGE MODELS SHOWING SIG VARIABILITY WITH SMALLER SCALE/WEAK
FEATURES THROUGH THE EXTENDED. INITIALLY WILL DEAL WITH CLIPPER
TYPE SYSTEM DROPPING OUT OF CANADA...MOVING THROUGH STATE LATER
SAT INTO SUNDAY. TIMING AND STRENGTH VARIABLE. HAVE STAYED WITH
LOWER CHANCE POPS. MODELS STILL SUGGEST SOME STEEP LAPSE RATES
INTO MONDAY WITH CHANCE OF SHOWERS CONTINUING. WAA BEGINS
TUE...AGAIN MERITING LOW POPS. SOME OF THE MODELS SUGGEST
BAROCLINIC ZONE LINGERING OVER NORTHERN WI THROUGH THE LATER PART
OF PERIOD...WITH SOME INSTABILITY PRESENT. AGAIN TIMING IN ISSUE.
RIGHT NOW WILL HIGHLIGHT THU WITH SMALL POPS.
MARINE...LOW MOVING NORTH EAST OUT OF PLAINS THROUGH CHICAGO
REGION WILL BRING INCREASING NE WINDS TO THE AREA. STRONGEST
GRADIENT AND FUNNELING OF WINDS EXPECTED OVER SOUTHERN BAY AND
LAKESHORE SOUTH OF STURGEON BAY. MINIMAL GALE GUST EXPECTED LATE
TONIGHT THROUGH FRI MORNING.
&&
.AVIATION...FOR 06Z TAFS. LOWER-END VFR/IFR CIGS WL PREVAIL THE
REST OF THE NGT. CONDITIONS SHOULD IMPROVE FRIDAY AS THE STORM
SYSTEM BRINING THE PRECIPITAITON TO THE AREA PULLS AWAY TO THE
EAST.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT FRIDAY FOR WIZ013-019>021-
031-073-074.
WINTER WEATHER ADVISORY UNTIL 4 AM CDT FRIDAY FOR WIZ030-035-036.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
946 PM CDT THU APR 19 2012
.UPDATE...PCPN INTENSITY...LIKELY THE MELTING OF BIG WET
SNOWFLAKES...OBVIOUSLY PLAYING A ROLE IN COOLING LOW-LEVELS
ENOUGH TO ALLOW SNOW REACH THE GROUND. LIQUID PCPN STILL OCCURRING
WHERE INTENSITIES WERE LIGHTER ON THE NW FLANK OF THE PCPN
SHIELD. HAVE TO ADMIT TO BEING SURPRISED WE GOT AS MUCH COOLING AS
WE DID GIVEN THE WARM SFC WET-BULB TEMPS AT THE START OF THE EVENT.
THE SRN EDGE OF THE RN/SN LINE NOW COMING MORE INTO ALIGNMENT
WITH THE ZERO DEGREE ISOTHERM ALOFT. SO THINK WE ARE LIKELY TO
SEE A MORE GRADUAL SWD SHIFT IN THE SNOW AREA THE REST OF THE NGT.
DON/T EXPECT MUCH IN THE WAY OF ACCUMS IN AREAS WHERE SNOW ISN/T
FALLING BY NOW.
LOOKING AT HOW QUICKLY PCPN IS DIMINISHING OUT TO THE WEST...
PROBABLY COULD HAVE ENDED WRN PART OF ADVISORY EVEN SOONER THAN
THE ADJUSTED 4 AM TIME I WENT WITH LAST HOUR/S UPDATE. BUT THAT
SHOULD BE AT LEAST A BETTER APPROXIMATION THAN PREVIOUS 7 AM
EXPIRATION. BASED ON SNOWFALL CRITERIA ALONE MAY NOT HAVE NEEDED
ADVISORY AT ALL FOR WOOD/PORTAGE AND MAYBE EVEN MARATHON. BUT STARTED
GETTING REPORTS OF TRAVEL ISSUES DUE TO SLUSH ON THE ROADS...SO
KEEPING ADVISORY SEEMED THE BEST WAY TO GO EVEN IF MANY LOCATIONS
IN THE SW CORNER OF THE FCST AREA DON/T MEET CRITERIA.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 839 PM CDT THU APR 19 2012...
UPDATE...WL TWEAK THE ADVISORY. MAIN CHG WL BE TO DROP IT SOONER
BACK IN CENTRAL WI...AS PCPN PULLING OUT MORE QUICKLY. TOYED WITH
PULLING PORTAGE...AS DON/T THINK MOST OF THE COUNTY WL GET MUCH
SNOW. BUT IN THE END DECIDED TO JUST KEEP IT IN AND SPECIFY TOTALS
WL BE MAINLY NW OF STE.
NEED TO ADJUST SOME SNOW ACCUM GRIDS AND WX GRIDS LATER TNGT.
UPDATED FCST SUITE WL BE OUT ASAP.
SKOWRONSKI
DISCUSSION ISSUED AT 531 PM CDT THU APR 19 2012...
UPDATE...TRICKY FCST TNGT. RAIN EXPECTED TO CHG TO SNOW ON THE NW
FLANK OF SML BUT FAIRLY INTENSE CYCLONE TRACKING TOWARD THE AREA.
SYSTEM SHOULD REMAIN AN OPEN WAVE...SO THE HEAVIEST PCPN WL FALL
AS THE SFC LOW APPROACHES WITH A SHARP DECR IN INTENSITY ONCE IT
CROSSES JUST S OF THE AREA AND STARTS TO HEAD OFF TO THE E.
CERTAINLY GOING TO GET ENOUGH PCPN TO PRODUCE WARNING CRITERIA
SNOWS...IF IT WAS ALL OR MOSTLY SNOW. PROBLEM IS THE CHANGEOVER.
HAVE WORKED THESE LATE SEASON EVENTS IN THE PAST...AND THE ONE
THING THAT BOTHERS ME RIGHT NOW IS THAT SFC/LOW-LEVEL WET-BULB
TEMPS ARE ALL WELL ABV FZG. MODELS INSIST LOW-LEVEL TEMPS WL COOL
OVERNIGHT...BUT HAVING WET-BULB TEMPS ABV FZG WL LIMIT THE HELP FM
EVAPORATIVE COOLING WHICH CAN OFTEN HELP GET THE CHANGEOVER GOING
AT THIS TIME OF YEAR. MELTING OF THE FALLING SNOW WL PROVIDE SOME
COOLING...BUT CAN/T LOSE TOO MUCH OF THE EVENT TO LIQUID IF FCST
SNOWFALL TOTALS ARE TO WORK OUT.
GOING FCST OKAY FOR NOW...WL CONT TO MONITOR AND PROBABLY MAKE
SOME ADJUSTMENTS LATER THIS EVENING.
RECEIVED ONE REPORT THUS FAR OF A MIX. THAT WAS FM OUT IN WAUPACA
COUNTY ABOUT AN HR AGO. RADAR RETURNS AND RUC MODEL SOUNDINGS
SUGGEST THAT WAS PROBABLY SLEET.
SKOWRONSKI
DISCUSSION ISSUED AT 339 PM CDT THU APR 19 2012...
SHORT TERM...TONIGHT AND FRIDAY. POTENTIAL FOR SIGNIFICANT
SNOWFALL IS THE MAIN CONCERN FOR TONIGHT. THE MODELS...BASED ON
TIME/HEIGHT SECTIONS...HAD SOME SUBSTANTIAL DIFFERENCES IN THEIR
PRECIPITATION TYPE FORECASTS. THE 09Z SREF HAD 0.87 INCHES LIQUID
EQUIVALENT OF SNOW STARTING AROUND 00Z AT RHI WHILE THE 12Z NAM
KEPT IT ALL RAIN WITH ONLY 0.04 TOTAL QPF.
LOW PRESSURE CENTERED AROUND NORTHWEST MISSOURI AT 20Z...IS
FORECAST TO PUSH NORTHEAST AND CROSS SOUTHERN LOWER MICHIGAN ON
FRIDAY. STRONG COLD ADVECTION IS EXPECTED TO CHANGE THE
PRECIPITATION TO SNOW. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF AN UPPER LEVEL JET MAX...ALONG WITH MID LEVEL
SHORT WAVE ENERGY WILL ACT WITH THE LOW TO PRODUCE PLENTY OF
PRECIPITATION. THERE IS ENOUGH MOISTURE ASSOCIATED WITH THE
SYSTEM TO SPREAD WARNING CRITERIA SNOW ACROSS A LARGE PART OF THE
AREA...BUT MUCH OF THE PRECIPITATION WILL HAVE FALLEN BEFORE TEMPERATURES
BECOME COOL ENOUGH FOR SNOW...ESPECIALLY IN THE SOUTHEAST PART OF
THE FORECAST AREA. HAVE KEPT TOTALS IN THE HIGHEST SWATH OF SNOW
BELOW WARNING CRITERIA AS A RESULT OF THIS.
ENDED UP GOING WITH...OR AT LEAST CLOSE TO...THE HPC WINTER
WEATHER ACCUMULATION TOTALS. HAVE OPTED TO KEEP THE ADVISORY AND
ADD WOOD AND PORTAGE COUNTIES FOR HIGHER AMOUNTS IN THE NORTHERN
PARTS OF THOSE COUNTIES.
THE SYSTEM SHOULD MOVE FAIRLY QUICKLY SO ONLY HELD ONTO SOME
CHANCE POPS EARLY FRIDAY MORNING. THIS FORECAST MAY REQUIRE MAJOR
SURGERY SO STAY TUNED FOR FURTHER UPDATES.
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
ZONAL FLOW EARLY IN PERIOD...WILL BECOME AMPLIFIED BY END OF
WEEKEND WITH TROF OVER EASTERN STATES AND OFF WEST COAST AND
RIDGE IN BETWEEN. TEMPERATURES WILL START OUT AT OR SLIGHTLY
BELOW NORMAL AND THEN SHOULD TRANSITION TO ABOVE NORMAL LEVELS BY
THE END OF NEXT WEEK AS UPPER RIDGE SHIFTS EASTWARD.
MID RANGE MODELS SHOWING SIG VARIABILITY WITH SMALLER SCALE/WEAK
FEATURES THROUGH THE EXTENDED. INITIALLY WILL DEAL WITH CLIPPER
TYPE SYSTEM DROPPING OUT OF CANADA...MOVING THROUGH STATE LATER
SAT INTO SUNDAY. TIMING AND STRENGTH VARIABLE. HAVE STAYED WITH
LOWER CHANCE POPS. MODELS STILL SUGGEST SOME STEEP LAPSE RATES
INTO MONDAY WITH CHANCE OF SHOWERS CONTINUING. WAA BEGINS
TUE...AGAIN MERITING LOW POPS. SOME OF THE MODELS SUGGEST
BAROCLINIC ZONE LINGERING OVER NORTHERN WI THROUGH THE LATER PART
OF PERIOD...WITH SOME INSTABILITY PRESENT. AGAIN TIMING IN ISSUE.
RIGHT NOW WILL HIGHLIGHT THU WITH SMALL POPS.
MARINE...LOW MOVING NORTH EAST OUT OF PLAINS THROUGH CHICAGO
REGION WILL BRING INCREASING NE WINDS TO THE AREA. STRONGEST
GRADIENT AND FUNNELING OF WINDS EXPECTED OVER SOUTHERN BAY AND
LAKESHORE SOUTH OF STURGEON BAY. MINIMAL GALE GUST EXPECTED LATE
TONIGHT THROUGH FRI MORNING.
&&
.AVIATION...FOR 00Z TAFS. EXPECT CIGS TO FALL QUICKLY THIS
EVENING...AND SHOULD BE PRIMARILY IN THE LOWER-END VFR OR IFR
RANGE ACRS THE SRN 2/3 OF THE FCST AREA. THE N MAY BE ABLE TO HOLD
UP MORE DUE TO LIGHTER PCPN AND DRY FEED IN FM THE NE. WINDS AT
GRB AND ATW WL REALLY GET GOING LATE THIS EVENING AND OVERNIGHT AS
DIRECTIONAL SHEAR DIMINISHES AND THEY COME ARND THROUGH 040 DEG.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT FRIDAY FOR WIZ013-019>021-
031-073-074.
WINTER WEATHER ADVISORY UNTIL 4 AM CDT FRIDAY FOR WIZ030-035-036.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
845 PM CDT THU APR 19 2012
.SHORT TERM...TONIGHT
845 PM CDT THU APR 19 2012
RADAR TRENDS AND LATEST RUNS OF THE MESO HRRR MODEL POINT TO AN
EARLIER EXIT EAST OF THE BROAD AREA OF PCPN ACROSS THE REGION. THERE
HAS BEEN SOME MIX OF RAIN/SNOW NORTH OF I-94...MORE SO INTO
NORTHEAST WI. WITH THE QUICKER EXIT THOUGH...THERE WILL BE LESS TIME
TO SWITCH TO SNOW...THUS LOWER QPF AND LOWER SNOW ACCUM POTENTIAL.
HAVE ACCELERATED THE EXIT OF THE PCPN CHANCES TO THE EAST AS A
RESULT...AND LOWERED THE SNOW ACCUMULATIONS. THERE COULD STILL BE
SOME SCATTERED TO ISOLATED SHOWERS POST THIS MAIN PCPN SHIELD...BUT
ACCUMS OF RAIN OR SNOW WITH THESE LOOK TO BE MINIMAL.
.LONG TERM...MONDAY THROUGH THURSDAY
305 PM CDT THU APR 19 2012
19.12 FORECAST MODELS IN REASONABLE AGREEMENT ON MONDAY...THEN START
TO DIVERGE TUESDAY NIGHT THROUGH THURSDAY. NORTHWEST FLOW ALOFT IF
EXPECTED ACROSS THE FORECAST AREA THROUGH AT LEAST WEDNESDAY AS A
BROAD UPPER RIDGE REMAINS IN PLACE ACROSS THE WESTERN CONUS.
FORECAST MODELS ARE HAVING SOME ISSUES HANDLING EMBEDDED FAST-MOVING
SHORTWAVE TROUGHS IN THE NORTHWEST FLOW. THE FIRST WAVE LOOKS TO
MOVE ACROSS THE FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY AS A WARM
FRONT PUSHES ACROSS THE REGION. THE FRONT WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE UPPER MISSISSIPPI RIVER VALLEY AS
IT MOVES THROUGH. PLAN ON WARMER TEMPERATURES ON WEDNESDAY WITH
HIGHS RANGING FROM THE MID 60S ACROSS NORTH CENTRAL WISCONSIN TO THE
MID 70S ACROSS NORTHEAST IOWA. ANOTHER SHORTWAVE IS EXPECTED TO PUSH
ACROSS THE AREA ON THURSDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS
AND THUNDERSTORMS.
&&
.AVIATION...
610 PM CDT THU APR 19 2012
RAIN WILL PERSIST ACROSS THE AREA THROUGH AT LEAST 06Z TONIGHT...AND
COULD MIX WITH -SN AT KRST BEFORE ENDING. LATEST HRRR SUGGEST THAT
THE PCPN SHOULD EXIT EAST OF KRST NEAR 07Z...AND KLSE AROUND 09Z.
SATURATED SOUNDINGS AND OBS POINT TO MVFR/IFR CIGS...AND THESE
SHOULD CONTINUE FOR MOST OF TONIGHT. AS THE RESPONSIBLE STORM SYSTEM
EXITS EAST...EXPECT IMPROVEMENT NEAR 12Z FRI MORNING...WITH LIKELY
VFR CONDITIONS BY 15Z OR SO.
WINDS WILL STAY RELATIVELY BRISK THROUGH THE NIGHT AS THE TIGHT
PRESSURE GRADIENT CONTINUES WITH LITTLE/IF ANY DIURNAL DECOUPLING.
CLEARER SKIES WILL PROMOTE MIXING AND LIKELY SOME GUSTINESS FROM
LATE MORNING THROUGH THE AFTERNOON FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 PM CDT THU APR 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...RIECK
LONG TERM....WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION...UPDATED
NWS GREEN BAY WI
839 PM CDT THU APR 19 2012
.UPDATE...WL TWEAK THE ADVISORY. MAIN CHG WL BE TO DROP IT SOONER
BACK IN CENTRAL WI...AS PCPN PULLING OUT MORE QUICKLY. TOYED WITH
PULLING PORTAGE...AS DON/T THINK MOST OF THE COUNTY WL GET MUCH
SNOW. BUT IN THE END DECIDED TO JUST KEEP IT IN AND SPECIFY TOTALS
WL BE MAINLY NW OF STE.
NEED TO ADJUST SOME SNOW ACCUM GRIDS AND WX GRIDS LATER TNGT.
UPDATED FCST SUITE WL BE OUT ASAP.
SKOWRONSKI
&&
.PREV DISCUSSION...ISSUED AT 531 PM CDT THU APR 19 2012...
UPDATE...TRICKY FCST TNGT. RAIN EXPECTED TO CHG TO SNOW ON THE NW
FLANK OF SML BUT FAIRLY INTENSE CYCLONE TRACKING TOWARD THE AREA.
SYSTEM SHOULD REMAIN AN OPEN WAVE...SO THE HEAVIEST PCPN WL FALL
AS THE SFC LOW APPROACHES WITH A SHARP DECR IN INTENSITY ONCE IT
CROSSES JUST S OF THE AREA AND STARTS TO HEAD OFF TO THE E.
CERTAINLY GOING TO GET ENOUGH PCPN TO PRODUCE WARNING CRITERIA
SNOWS...IF IT WAS ALL OR MOSTLY SNOW. PROBLEM IS THE CHANGEOVER.
HAVE WORKED THESE LATE SEASON EVENTS IN THE PAST...AND THE ONE
THING THAT BOTHERS ME RIGHT NOW IS THAT SFC/LOW-LEVEL WET-BULB
TEMPS ARE ALL WELL ABV FZG. MODELS INSIST LOW-LEVEL TEMPS WL COOL
OVERNIGHT...BUT HAVING WET-BULB TEMPS ABV FZG WL LIMIT THE HELP FM
EVAPORATIVE COOLING WHICH CAN OFTEN HELP GET THE CHANGEOVER GOING
AT THIS TIME OF YEAR. MELTING OF THE FALLING SNOW WL PROVIDE SOME
COOLING...BUT CAN/T LOSE TOO MUCH OF THE EVENT TO LIQUID IF FCST
SNOWFALL TOTALS ARE TO WORK OUT.
GOING FCST OKAY FOR NOW...WL CONT TO MONITOR AND PROBABLY MAKE
SOME ADJUSTMENTS LATER THIS EVENING.
RECEIVED ONE REPORT THUS FAR OF A MIX. THAT WAS FM OUT IN WAUPACA
COUNTY ABOUT AN HR AGO. RADAR RETURNS AND RUC MODEL SOUNDINGS
SUGGEST THAT WAS PROBABLY SLEET.
SKOWRONSKI
DISCUSSION ISSUED AT 339 PM CDT THU APR 19 2012...
SHORT TERM...TONIGHT AND FRIDAY. POTENTIAL FOR SIGNIFICANT
SNOWFALL IS THE MAIN CONCERN FOR TONIGHT. THE MODELS...BASED ON
TIME/HEIGHT SECTIONS...HAD SOME SUBSTANTIAL DIFFERENCES IN THEIR
PRECIPITATION TYPE FORECASTS. THE 09Z SREF HAD 0.87 INCHES LIQUID
EQUIVALENT OF SNOW STARTING AROUND 00Z AT RHI WHILE THE 12Z NAM
KEPT IT ALL RAIN WITH ONLY 0.04 TOTAL QPF.
LOW PRESSURE CENTERED AROUND NORTHWEST MISSOURI AT 20Z...IS
FORECAST TO PUSH NORTHEAST AND CROSS SOUTHERN LOWER MICHIGAN ON
FRIDAY. STRONG COLD ADVECTION IS EXPECTED TO CHANGE THE
PRECIPITATION TO SNOW. UPPER DIVERGENCE ASSOCIATED WITH THE RIGHT
ENTRANCE REGION OF AN UPPER LEVEL JET MAX...ALONG WITH MID LEVEL
SHORT WAVE ENERGY WILL ACT WITH THE LOW TO PRODUCE PLENTY OF
PRECIPITATION. THERE IS ENOUGH MOISTURE ASSOCIATED WITH THE
SYSTEM TO SPREAD WARNING CRITERIA SNOW ACROSS A LARGE PART OF THE
AREA...BUT MUCH OF THE PRECIPITATION WILL HAVE FALLEN BEFORE TEMPERATURES
BECOME COOL ENOUGH FOR SNOW...ESPECIALLY IN THE SOUTHEAST PART OF
THE FORECAST AREA. HAVE KEPT TOTALS IN THE HIGHEST SWATH OF SNOW
BELOW WARNING CRITERIA AS A RESULT OF THIS.
ENDED UP GOING WITH...OR AT LEAST CLOSE TO...THE HPC WINTER
WEATHER ACCUMULATION TOTALS. HAVE OPTED TO KEEP THE ADVISORY AND
ADD WOOD AND PORTAGE COUNTIES FOR HIGHER AMOUNTS IN THE NORTHERN
PARTS OF THOSE COUNTIES.
THE SYSTEM SHOULD MOVE FAIRLY QUICKLY SO ONLY HELD ONTO SOME
CHANCE POPS EARLY FRIDAY MORNING. THIS FORECAST MAY REQUIRE MAJOR
SURGERY SO STAY TUNED FOR FURTHER UPDATES.
LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY
ZONAL FLOW EARLY IN PERIOD...WILL BECOME AMPLIFIED BY END OF
WEEKEND WITH TROF OVER EASTERN STATES AND OFF WEST COAST AND
RIDGE IN BETWEEN. TEMPERATURES WILL START OUT AT OR SLIGHTLY
BELOW NORMAL AND THEN SHOULD TRANSITION TO ABOVE NORMAL LEVELS BY
THE END OF NEXT WEEK AS UPPER RIDGE SHIFTS EASTWARD.
MID RANGE MODELS SHOWING SIG VARIABILITY WITH SMALLER SCALE/WEAK
FEATURES THROUGH THE EXTENDED. INITIALLY WILL DEAL WITH CLIPPER
TYPE SYSTEM DROPPING OUT OF CANADA...MOVING THROUGH STATE LATER
SAT INTO SUNDAY. TIMING AND STRENGTH VARIABLE. HAVE STAYED WITH
LOWER CHANCE POPS. MODELS STILL SUGGEST SOME STEEP LAPSE RATES
INTO MONDAY WITH CHANCE OF SHOWERS CONTINUING. WAA BEGINS
TUE...AGAIN MERITING LOW POPS. SOME OF THE MODELS SUGGEST
BAROCLINIC ZONE LINGERING OVER NORTHERN WI THROUGH THE LATER PART
OF PERIOD...WITH SOME INSTABILITY PRESENT. AGAIN TIMING IN ISSUE.
RIGHT NOW WILL HIGHLIGHT THU WITH SMALL POPS.
MARINE...LOW MOVING NORTH EAST OUT OF PLAINS THROUGH CHICAGO
REGION WILL BRING INCREASING NE WINDS TO THE AREA. STRONGEST
GRADIENT AND FUNNELING OF WINDS EXPECTED OVER SOUTHERN BAY AND
LAKESHORE SOUTH OF STURGEON BAY. MINIMAL GALE GUST EXPECTED LATE
TONIGHT THROUGH FRI MORNING.
&&
.AVIATION...FOR 00Z TAFS. EXPECT CIGS TO FALL QUICKLY THIS
EVENING...AND SHOULD BE PRIMARILY IN THE LOWER-END VFR OR IFR
RANGE ACRS THE SRN 2/3 OF THE FCST AREA. THE N MAY BE ABLE TO HOLD
UP MORE DUE TO LIGHTER PCPN AND DRY FEED IN FM THE NE. WINDS AT
GRB AND ATW WL REALLY GET GOING LATE THIS EVENING AND OVERNIGHT AS
DIRECTIONAL SHEAR DIMINISHES AND THEY COME ARND THROUGH 040 DEG.
SKOWRONSKI
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT FRIDAY FOR WIZ013-019>021-
031-073-074.
WINTER WEATHER ADVISORY UNTIL 4 AM CDT FRIDAY FOR WIZ030-035-036.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
610 PM CDT THU APR 19 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
305 PM CDT THU APR 19 2012
MAIN FORECAST CONCERNS ARE ON RAIN/SNOW TONIGHT. FOCUS THEN TURNS TO
TEMPERATURES FRIDAY MORNING THROUGH SATURDAY MORNING...AND RAIN
SHOWER CHANCES SATURDAY INTO SUNDAY.
LATEST RADAR SHOWED A BROAD AREA OF MODERATE RAIN ACROSS MUCH OF
THE FORECAST AREA. NORTHERN CLARK AND TAYLOR COUNTIES HAVEN/T SEEN
ANY RAIN YET TODAY. LOOK FOR THE RAIN TO MOVE INTO THESE AREAS
LATE THIS AFTERNOON.
LOOK FOR SHOWERS TO PERSIST ACROSS MUCH OF THE FORECAST AREA THIS
EVENING. THE RAIN IS EXPECTED TO SWITCH OVER TO SNOW NORTH OF
INTERSTATE 94 EARLY THIS EVENING. THE SWITCH OVER WILL GRADUALLY
ADVANCE SOUTHWARD AS COLDER AIR GETS WRAPPED INTO THE LOW. STRONG
FRONTOGENESIS WILL PERSIST FROM JUST ABOVE THE SURFACE THROUGH 600
MB...LEADING TO HEAVY PRECIPITATION RATES EARLY THIS EVENING. ONCE
THE RAIN SWITCHES OVER TO SNOW ACROSS SOUTHERN
TAYLOR/JACKSON/NORTHEAST MONROE...AND NORTHERN ADAMS/JUNEAU...THE
SNOW MAY BECOME HEAVY AT TIMES WITH 1 TO 3 INCHES OF ACCUMULATION
POSSIBLE BY EARLY FRIDAY MORNING. THE MAIN CONCERN WITH THE SNOW
ACCUMULATION IS SURFACE TEMPERATURES HOVERING NEAR TO JUST ABOVE
FREEZING. SIGNIFICANT MELTING SHOULD OCCUR WITH THE INITIAL ONSET
BUT FEEL THE SNOWFALL RATES WILL BE HIGH ENOUGH TO LEAD TO SOME
LIGHT TO MODERATE ACCUMULATIONS ALONG AND NORTH OF THE I-94
CORRIDOR. THE HEAVY...WET NATURE OF THE SNOW COULD BRING DOWN
BRANCHES ESPECIALLY SINCE MANY TREE ACROSS THE AREA HAVE ALREADY
PARTIALLY OR FULLY LEAFED OUT. A BRIEF PERIOD OF LIGHT SNOW IS
POSSIBLE ACROSS SOUTHEAST MINNESOTA INTO PORTIONS OF SOUTHWEST
INTO WEST CENTRAL WISCONSIN WITH LITTLE TO NO ACCUMULATIONS
EXPECTED. FAR SOUTHWEST WISCONSIN AND NORTHEAST IOWA SHOULD STAY
WARM ENOUGH FOR THE PRECIPITATION TO FALL MAINLY AS RAIN. THE
COOLER AIR WILL OVERSPREAD THE AREA LATE TONIGHT AS COOL HIGH
PRESSURE BUILDS IN BEHIND THE HIGH. LOOK FOR RAIN/SNOW TO TAPER
OFF FROM WEST TO EAST LATE TONIGHT. OVERNIGHT LOWS WILL RANG FROM
AROUND 30 ACROSS NORTH CENTRAL WISCONSIN TO THE UPPER 30S ACROSS
NORTHEAST IOWA.
HIGH PRESSURE WILL PROVIDE DRY AND QUIET CONDITIONS ACROSS THE ARA
ON FRIDAY. PLAN ON PARTLY SUNNY SKIES WITH HIGH TEMPERATURES RANGING
FROM THE UPPER 40S ACROSS NORTH CENTRAL WISCONSIN TO AROUND 50
ACROSS NORTHEAST IOWA. MOSTLY CLEAR SKIES FRIDAY NIGHT WILL LEAD TO
FROST/FREEZE CONCERNS WITH TEMPERATURES FALLING INT THE UPPER 20S TO
LOWER 30S. THIS IS ESPECIALLY A CONCERN ACROSS CENTRAL INTO NORTH
CENTRAL WISCONSIN...WHERE FAVORED COLD AREAS ARE EXPECTED TO FALL
INTO THE UPPER 20S. HAVE ADDED AREAS OF FROST ACROSS CENTRAL INTO
NORTH CENTRAL WISCONSIN AND PATCHY FROST ACROSS ALL OF SOUTHWEST
WISCONSIN INTO PORTIONS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
A FAST MOVING SHORTWAVE TROUGH WILL MOVE ACROSS SOUTHERN
SASKATCHEWAN AND DIVE SOUTHEAST THROUGH NORTH DAKOTA LATE FRIDAY
NIGHT. THIS SHORTWAVE IS EXPECTED TO ADVANCE SOUTHEAST INTO THE
UPPER MISSISSIPPI RIVER VALLEY BY LATE SATURDAY MORNING.SOUTH WINDS
WILL INCREASE ACROSS THE REGION ON SATURDAY AS THE WAVE MOVES IN AND
SURFACE LOW PRESSURE DEEPENS ACROSS EAST CENTRAL MN AND WEST CENTRAL
WI. PLAN ON SOUTH/SOUTHEAST WINDS OF 10 TO 20 MPH AS THE LOW MOVES
IN. LOOK FOR RAIN SHOWERS TO SPREAD ACROSS THE AREA FROM NORTHWEST
TO SOUTHEAST ON SATURDAY. MODELS ARE IN MUCH BETTER AGREEMENT TODAY
REGARDING THE TIMING AND PLACEMENT OF THIS FEATURE. LOCATIONS ALONG
AND EAST OF THE MISSISSIPPI RIVER WILL SEE THE HIGHEST RAINFALL
AMOUNTS FROM THIS SYSTEM...BEING CLOSER TO THE UPPER LEVEL WAVE.
THESE AREA SHOULD SEE AROUND A TENTH OF AN INCH OF RAINFALL BY
SATURDAY EVENING. LOCATIONS WEST OF THE RIVER SHOULD SEE A FEW
HUNDREDTHS. DECIDED TO RAISE PRECIPITATION CHANCES ACROSS THE AREA
ON SATURDAY. THESE WILL LIKELY NEED TO BE INCREASES FURTHER IF MODEL
TRENDS CONTINUE. PLAN ON HIGH TEMPERATURES ON SATURDAY RANGING FROM
THE UPPER 40S TO LOWER 50S ACROSS NORTH CENTRAL WISCONSIN TO THE MID
50S ACROSS PORTIONS OF NORTHEAST IOWA. A SECONDARY SHORTWAVE IS
EXPECTED TO PUSH ACROSS THE FORECAST AREA ON SUNDAY. VERY STEEP
LAPSE RATES AND LIFT ASSOCIATED WITH THE SHORTWAVE...WILL LEAD TO
SCATTERED RAIN SHOWERS...MAINLY ALONG AND EAST OF THE MISSISSIPPI
RIVER. LOOK FOR HIGHS ON SUNDAY TO RANGE FROM THE LOWER 50S ACROSS
NORTH CENTRAL WISCONSIN TO AROUND 60 ACROSS NORTHEAST IOWA.
.LONG TERM...MONDAY THROUGH THURSDAY
305 PM CDT THU APR 19 2012
19.12 FORECAST MODELS IN REASONABLE AGREEMENT ON MONDAY...THEN START
TO DIVERGE TUESDAY NIGHT THROUGH THURSDAY. NORTHWEST FLOW ALOFT IF
EXPECTED ACROSS THE FORECAST AREA THROUGH AT LEAST WEDNESDAY AS A
BROAD UPPER RIDGE REMAINS IN PLACE ACROSS THE WESTERN CONUS.
FORECAST MODELS ARE HAVING SOME ISSUES HANDLING EMBEDDED FAST-MOVING
SHORTWAVE TROUGHS IN THE NORTHWEST FLOW. THE FIRST WAVE LOOKS TO
MOVE ACROSS THE FORECAST AREA TUESDAY NIGHT INTO WEDNESDAY AS A WARM
FRONT PUSHES ACROSS THE REGION. THE FRONT WILL BRING A CHANCE OF
SHOWERS AND THUNDERSTORMS TO THE UPPER MISSISSIPPI RIVER VALLEY AS
IT MOVES THROUGH. PLAN ON WARMER TEMPERATURES ON WEDNESDAY WITH
HIGHS RANGING FROM THE MID 60S ACROSS NORTH CENTRAL WISCONSIN TO THE
MID 70S ACROSS NORTHEAST IOWA. ANOTHER SHORTWAVE IS EXPECTED TO PUSH
ACROSS THE AREA ON THURSDAY BRINGING ADDITIONAL CHANCES FOR SHOWERS
AND THUNDERSTORMS.
&&
.AVIATION...
610 PM CDT THU APR 19 2012
RAIN WILL PERSIST ACROSS THE AREA THROUGH AT LEAST 06Z TONIGHT...AND
COULD MIX WITH -SN AT KRST BEFORE ENDING. LATEST HRRR SUGGEST THAT
THE PCPN SHOULD EXIT EAST OF KRST NEAR 07Z...AND KLSE AROUND 09Z.
SATURATED SOUNDINGS AND OBS POINT TO MVFR/IFR CIGS...AND THESE
SHOULD CONTINUE FOR MOST OF TONIGHT. AS THE RESPONSIBLE STORM SYSTEM
EXITS EAST...EXPECT IMPROVEMENT NEAR 12Z FRI MORNING...WITH LIKELY
VFR CONDITIONS BY 15Z OR SO.
WINDS WILL STAY RELATIVELY BRISK THROUGH THE NIGHT AS THE TIGHT
PRESSURE GRADIENT CONTINUES WITH LITTLE/IF ANY DIURNAL DECOUPLING.
CLEARER SKIES WILL PROMOTE MIXING AND LIKELY SOME GUSTINESS FROM
LATE MORNING THROUGH THE AFTERNOON FRIDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
305 PM CDT THU APR 19 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM....WETENKAMP
AVIATION.....RIECK
AREA FORECAST DISCUSSION...UPDATED
NWS MILWAUKEE/SULLIVAN WI
100 PM CDT WED APR 18 2012
.UPDATE...MOST OF THE MORNING SHOWERS ACROSS SOUTHERN WISCONSIN
HAVE EITHER LIFTED NORTH OR WIPED OUT. STILL HOLDING ON TO A
CHANCE FOR SHOWERS AND STORMS THIS AFTERNOON AS THE WEAK SFC COLD
FRONT MOVES THOUGH. NOT VERY CONFIDENT IN THE CHANCE THOUGH...AS
LATEST WRF NMM...WRF ARW...AND HRRR ARE ALL SIGNIFICANTLY OVERDOING
THE CURRENT RADAR COVERAGE. SOUNDINGS ARE SHOWING A LOT OF DRY
AIR...WHICH MAY BE THE REASON THINGS ARE NOT FIRING ALONG THE
FRONT. STILL...SEEING SOME CAPE DEVELOPING WITH A DECENT AMOUNT OF
SUNSHINE...SO NOT GOING TO LET GO OF CHANE FOR FURTHER DEVELOPMENT
JUST YET. OTHERWISE...TEMPS GENERALLY ON TRACK FOR THIS AFTERNOON.
&&
.AVIATION/18Z TAFS/...STILL THINK THERE COULD BE A FEW SHOWERS AND
STORMS THAT DEVELOP AHEAD OF AN APPROACHING COLD FRONT THIS
AFTERNOON. THIS SYSTEM SEEMS TO BE DRIER THAN EXPECTED...SO
CONFIDENCE IN FURTHER PRECIP DEVELOPMENT IS NOT VERY HIGH.
THE FRONT WILL SAG SOUTH OF THE WISCONSIN THIS EVENING...STALLING
OVER NORTHERN ILLINOIS. THERE WILL BE LOW CHANCES FOR A SHOWER OR
STORM NEAR THE ILLINOIS BORDER TONIGHT...BEFORE A SHORTWAVE
RIDING THROUGH THE BAROCLINIC ZONE BRINGS WIDESPREAD RAIN TO
SOUTHERN WISCONSIN THURSDAY AND THURSDAY NIGHT.
EXPECT VFR CONDITIONS TO PREVAIL THROUGH TONIGHT...WITH
DETERIORATING CONDITIONS DURING THE DAY THURSDAY. CIGS WILL LIKELY
DROP TO MVFR TOMORROW...POSSIBLY IFR BY EVENING. SOME LOWER VSBYS
LIKELY TOO AT TIMES WITH THE HEAVIER PRECIP.
&&
.PREV DISCUSSION... /ISSUED 338 AM CDT WED APR 18 2012/
SHORT TERM...
TODAY AND TONIGHT...FORECAST CONFIDENCE...MEDIUM
MID LEVEL SHORTWAVE EXITING THE NORTHERN PLAINS WILL MOVE ACROSS
NORTHERN WISCONSIN AND THE LAKE SUPERIOR AREA TODAY. ASSOCIATED
UPPER LEVEL DIVERGENCE PUSHES ACROSS NORTHERN AND CENTRAL WISCONSIN
BY EARLY AFTERNOON. 850 MB LOW LEVEL JET OF ALMOST 60 KNOTS PUSHES
INTO NORTHEAST WISCONSIN BY 7AM CDT. FAIRLY STRONG MOISTURE
CONVERGENCE OF ALMOST 30 G/KG/12 HR OVER MAINLY NORTHEAST WISCONSIN
THIS MORNING WITH MUCH WEAKER VALUES AROUND 4 G/KG/12 HR ACROSS THE
SOUTH BY NOON. THIS RESULTS IN FAIRLY STRONG 700 MB UPWARD MOTION
OF 13 UBAR/SEC MAINLY ACROSS NORTHERN WISCONSIN WITH MUCH WEAKER
UPWARD MOTION OVER SOUTHERN WISCONSIN.
AS A RESULT EXPECT MOST OF THE SHOWERS/THUNDERSTORMS TO OCCUR TO THE
NORTH WITH THE WARM AIR ADVECTION THIS MORNING.
0-1 KM CAPE VALUES OF ALMOST 500M J/KG OCCUR THIS AFTERNOON ALONG
THE TRAILING COLD FRONT. THEREFORE EXPECT THE BEST CHANCE OF
THUNDERSTORMS TO BE THIS AFTERNOON WITH THE COLD FRONT. LOW LEVEL
LAPSE RATES ARE RATHER STEEP WITH VALUES AROUND 9.5 C/KM BELOW 800
MB. HOWEVER MID LEVEL LAPSE RATES ARE MARGINAL. 6 KM BULK SHEAR
VALUES RISE TO BETWEEN 40 AND 50 KNOTS LATER THIS AFTERNOON.
NEXT PROBLEM IS THAT THE FRONT STALLS OUT JUST SOUTH OF THE
WISCONSIN ILLINOIS BORDER TONIGHT...ALONG WITH LINGERING MOISTURE
AND MODEST ELEVATED CAPE AROUND 120 J/KG LIFTED FROM AROUND 5000 FT.
THEREFORE WILL CONTINUE A LOW CHANCE OF SHOWERS/THUNDERSTORMS FAR
SOUTH.
THURSDAY THROUGH FRIDAY...FORECAST CONFIDENCE IS HIGH.
ANOTHER POTENT SHORTWAVE IN THE TRAIN OF WAVES TRACKING ALONG THE
ZONAL 500MB FLOW WILL REACH WI THU MORNING. AT THIS TIME...500MB
FLOW WILL BEGIN TO DEVELOP A TROUGH IN THE CENTER OF THE
COUNTRY...AND THE 850MB BAROCLINIC ZONE WILL STRENGTHEN OVER CENTRAL
WI AND THE PRECIP AREA ASSOCIATED WITH THE VORTICITY ADVECTION AND
STRONG DYNAMIC FORCING WILL REMAIN STATIONARY ACROSS SOUTHERN WI ALL
DAY THU AND INTO THU NIGHT. THE MODELS KEEP PRECIP ACROSS SOUTHEAST
WI THROUGH FRI AFTERNOON UNTIL THE 500MB LOW CLOSES OFF OVER TEXAS
AND THE 850MB BAROCLINIC ZONE FINALLY SHIFTS SOUTHEAST OF WI. THE
SURFACE WARM FRONT MAY MAKE IT INTO FAR SOUTHERN WI BY 00Z FRI AND
THEN SHIFT BACK SOUTH AFTER 06Z FRI. THE ECMWF AND CANADIAN PUSH THE
WARM FRONT FURTHER NORTH THAN THE NAM AND GFS.
INGREDIENTS COME TOGETHER ON THU TO SUPPORT A PROLONGED PRECIP EVENT
OVER SOUTHERN WI ON THU...ESPECIALLY AROUND 18Z. STRONG SLOPED
FRONTOGENESIS...STRONG OMEGA FROM 925MB THROUGH 500MB...AND THE LOW
LEVEL JET NOSING INTO SOUTHERN WI...AS WELL AS STRONG UPPER LEVEL
DIVERGENCE IN THE RIGHT ENTRANCE REGION OF THE UPPER JET. THERE WILL
BE PLENTY OF MOISTURE FEEDING INTO THE REGION...WITH INTENSE
ISENTROPIC LIFT AND SPECIFIC HUMIDITY VALUES OF 6 TO 8 G/KG.
PRECIPITABLE WATER VALUES OVER AN INCH...WITH UP TO 1.22 INCHES PER
00Z NAM BY 00Z FRI. ECMWF AND CANADIAN HAVE THE HIGHEST QPF VALUES
ACROSS SOUTH CENTRAL AND EAST CENTRAL WI...TOTALING 1.5 INCHES OR
MORE. GFS AND NAM ARE MORE PROGRESSIVE WITH THE PRECIP AREA AND THUS
HAVE LOWER QPF TOTALS...AROUND 1 INCH OR LESS. ALL MODELS SHOW A
GOOD AMOUNT OF QPF OVER THE FORECAST AREA BETWEEN 18Z THU AND 00Z
FRI...BUT THE ECMWF AND CANADIAN MODELS KEEP PRODUCING HIGH QPF
AMOUNTS THROUGH 12Z FRI AND THEN BEGIN TO TAPER THEM OFF AFTER 18Z
FRI. HPC LEANED HEAVILY ON ECMWF AND CANADIAN QPF VALUES...BUT
FORECAST OFFICES IN THE WI AREA MODERATED THE VALUES DOWNWARD A BIT.
TOTAL RAINFALL AMOUNTS COULD BE ON THE ORDER OF 2 INCHES. HOWEVER
GIVEN THE LONG TIME FRAME OF WHEN IT FALLS...FLOODING DOES NOT
APPEAR TO BE A CONCERN. ISOLATED THUNDER STILL MENTIONED FOR THU
AFTERNOON DUE TO THE STRONG DYNAMICS OF THE SYSTEM. NO SEVERE
EXPECTED SINCE THERE IS VERY LITTLE CONVECTIVE INSTABILITY. STEADY
RAIN EVENT WITH A FEW HEAVIER SHOWERS EMBEDDED.
THERE IS GENERAL MODEL AGREEMENT FOR LINGERING RAIN SHOWERS ALL DAY
FRI DUE TO DEFORMATION ON THE NORTHWEST SIDE OF THE DEPARTING
LOW...AS WELL AS STEEP LOW LEVEL LAPSE RATES. A FEW SNOW FLAKES
COULD MIX INTO THE RAIN...ESPECIALLY TOWARD CENTRAL WI...BUT NO
ACCUMULATION ANTICIPATED. TEMPS WILL BE COOL ON FRI WITH BRISK NNE
WINDS OFF LAKE MICHIGAN.
LONG TERM...
FRIDAY NIGHT THROUGH WEDNESDAY...FORECAST CONFIDENCES IS MEDIUM.
SURFACE HIGH PRESSURE SETTLING INTO THE UPPER MIDWEST WILL KEEP
QUIET AND SEASONABLY COOL WEATHER ACROSS SOUTHERN WI FOR THE
WEEKEND. BRIEF PERIOD OF CLEAR SKIES EXPECTED IN THE WAKE OF THE
DEPARTING LOW. THEN A 500MB SHORTWAVE WILL MOVE ACROSS NORTHERN MN
AND WI IN THE NORTHWEST FLOW AND BRING CLOUDS AND A SLIGHT CHANCE
FOR SHOWERS ON SUNDAY.
NEXT CHANCE FOR PRECIP WILL BE WITH A WARM FRONT AND POTENT
SHORTWAVE APPROACHING THE GREAT LAKES REGION ON TUE THROUGH WED.
THUNDER POSSIBLE WITH THIS SYSTEM.
AVIATION/12Z TAFS/...
SURFACE LOW WILL TRACK ACROSS THE LAKE SUPERIOR REGION THIS
AFTERNOON. EXPECT VFR CIGS IN THE WARM AIR ADVECTION WITH A 50 KNOT
850 MB LOW LEVEL JET WITH MUCH OF THE SHOWERS/THUNDERSTORMS OVER
CENTRAL AND NORTHERN WISCONSIN THIS MORNING.
EXPECT A CHANCE OF THUNDERSTORMS OVER THE FORECAST AREA THIS
AFTERNOON AS A TRAILING COLD FRONT MOVES ACROSS SOUTHERN WISCONSIN.
MAINLY VFR CIGS WITH CUMULUS BUT MVFR CIGS AND BRIEF IFR VSBYS
CERTAINLY POSSIBLE WITHIN THUNDERSTORMS.
THE FRONT WILL STALL JUST SOUTH OF THE ILLINOIS BORDER TONIGHT.
MAINLY VFR CIGS BUT SOME MVFR CIGS POSSIBLE ALONG THE FRONT.
MARINE...
SOUTH TO SOUTHWEST WINDS WILL GUST TO 25 TO 30 KNOTS ALONG THE SHORE
AHEAD OF AN APPROACHING COLD FRONT TODAY. HOWEVER WITH THE COLD
WATERS MORE OF AN INVERSION IS EXPECTED TOWARD OPEN WATERS...SO
WINDS MAY BE LESS THERE. A SMALL CRAFT ADVISORY IS IN EFFECT.
THE COLD FRONT WILL STALL ACROSS FAR NORTHERN ILLINOIS TONIGHT WITH
NORTHEAST WINDS LATER TONIGHT. HOWEVER WINDS WILL BE DIMINISHING.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT THIS EVENING FOR LMZ643>646.
&&
$$
UPDATE...DDV
TODAY/TONIGHT AND AVIATION/MARINE...HENTZ
THURSDAY THROUGH TUESDAY...MRC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1237 PM CDT WED APR 18 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
710 AM CDT WED APR 18 2012
UPDATE...HAVE UPDATED THE FORECAST IN REGARD TO THE RAIN SHOWERS
CURRENTLY MOVING ACROSS THE REGION. MUCH OF THE LOW LEVEL MOISTURE
ADVECTION HAS BROUGHT THESE SHOWERS OUT AHEAD OF THE COLD FRONT
WITH MUCH OF THIS SHOWER ACTIVITY INTO CENTRAL WISCONSIN BY LATER
THIS MORNING. SKIES ARE ALSO CLEARING OUT ACROSS MINNESOTA...SO
HAVE GONE WITH A MUCH FASTER END TO THE RAIN THIS
MORNING/AFTERNOON ALONG WITH THE CLOUD TRENDS. HAVE HELD ONTO A
SMALL CHANCE FOR RAIN SHOWERS LATE THIS AFTERNOON FROM SOUTHWEST
WISCONSIN INTO NORTHEAST IOWA FOR THE OFF CHANCE THAT SOME SHOWERS
COULD DEVELOP ALONG THE STALLING OUT FRONT...WHICH IS WHAT THE
PAST FEW RUNS OF THE HRRR HAVE SHOWN. CONFIDENCE IN THOSE SHOWERS
ACTUALLY DEVELOPING AT THIS POINT ARE VERY LOW THOUGH GIVEN THE
ADVANCEMENT OF THIS MORNINGS CONVECTION.
PREVIOUS SHORT TERM AFD...
FIRST CONCERN WILL BE SHOWERS/THUNDERSTORMS TODAY...THEN RAIN AGAIN
THURSDAY INTO THURSDAY NIGHT WITH PERHAPS SOME SNOW MIXING IN
THURSDAY NIGHT. LOOK FOR A CHANCE OF LINGERING RAIN/SHOWERS ON
FRIDAY AS WELL.
CURRENT WATER VAPOR IMAGERY SHOWING A RATHER DYNAMIC MID-LEVEL WAVE
PUSHING INTO WESTERN MN. AT THE SURFACE...LOW PRESSURE WAS LOCATED
OVER SOUTHWEST MN WITH WARM AIR ADVECTION/STRONG ISENTROPIC LIFT AND
MOISTURE TRANSPORT PRODUCING SCATTERED SHRA/TS ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY REGION. SO FAR MOST OF THIS ACTIVITY HAS
BEEN CONFINED ALONG/NORTH OF I-90. MEANWHILE...THE COLD FRONT FROM
THE LOW WAS PRODUCING A DECENT LINE OF THUNDERSTORMS FROM SOUTHWEST
MN INTO NORTHEAST NEB. OTHERWISE...UNDER MOSTLY CLOUDY
SKIES...TEMPERATURES AT 3 AM ACROSS THE AREA WERE IN THE MID 40S TO
MID 50S.
FOR TODAY...WILL BE WATCHING THAT LOW AND COLD FRONT TRACK EAST
ACROSS THE AREA AS THE NAM HAS 0-3KM MUCAPE INCREASING INTO THE
800-1100 J/KG RANGE THIS MORNING AND AFTERNOON. THERE IS ALSO AMPLE
SHEAR PRESENT IN THIS LAYER IN THE 35-40KT RANGE. BUFKIT ALSO
SHOWING MOST OF THIS ACTIVITY FAIRLY HIGH BASED. SO...THINKING THERE
MAY BE AN OUTSIDE CHANCE OF SOME SUB-SEVERE HAIL/WIND WITH A FEW OF
THESE STORMS. HIGHEST THREAT AREA FOR THIS OCCURRING LOOKS TO BE
SOUTHEAST OF A LINE FROM NEAR SPARTA AND VIROQUA WI...TO NEAR
OELWEIN IA. OTHERWISE...LOOK FOR GUSTY SOUTHWEST WINDS THIS MORNING
IN THE 15-30 MPH RANGE SHIFT TO THE WEST/NORTHWEST THIS AFTERNOON
WITH HIGHS TOPPING OFF WELL INTO THE 60S.
FOR TONIGHT...WILL SEE CLEARING EARLY IN THE EVENING WITH THE COLD
FRONT SLIDING SOUTHEAST OF THE AREA AND THEN STALLING OUT ACROSS NORTHERN
IL INTO CENTRAL IA. WEAK CYCLOGENESIS OVER THE CENTRAL PLAINS WILL
THEN PRODUCE ISENTROPIC LIFT/MOISTURE TRANSPORT ACROSS THIS FRONTAL
BOUNDARY FOR INCREASING CLOUDS AGAIN AFTER MIDNIGHT. ANY RAIN LOOKS
LIKE IT WILL HOLD OFF SOUTH/WEST OF THE AREA. INCREASING ISENTROPIC
LIFT/MOISTURE TRANSPORT AHEAD OF THE THE WEAK WAVE OF LOW PRESSURE
OVER THE PLAINS SPREADS RAIN INTO THE AREA ON THURSDAY. NAM STILL
SHOWING SOME WEAK ELEVATED CAPE IN THE 850-700MB LAYER FOR PERHAPS
AN ISOLATED CLAP OR TWO OF THUNDER EMBEDDED IN THE RAIN SHIELD.
OTHERWISE...EASTERLY FLOW AND RAIN WILL MAKE FOR A RATHER RAW DAY
WITH HIGHS STRUGGLING INTO THE UPPER 40S TO MIDDLE 50S.
THE WAVE OF LOW PRESSURE MOVES ACROSS NORTHERN IL THURSDAY
NIGHT..DRAGGING COOLER AIR IN ACROSS THE REGION. THIS IS EXPECTED TO
PRODUCE A COOLING DEFORMATION AREA WITH A PERHAPS A MIX OF A
RAIN/SNOW ACROSS PORTIONS OF THE AREA LATE IN THE NIGHT. NO SNOW
ACCUMULATION IS EXPECTED THOUGH.
ON FRIDAY...THE LOW TRACK EAST INTO THE EASTERN GREAT LAKES REGION
WITH PERHAPS SOME LINGERING DEFORMATION PRECIPITATION IN THE
MORNING. MEANWHILE...THE COOL/RATHER DEEP MID-LEVEL TROUGH TRACKS
OVER OUR AREA DURING THE DAY. THE NAM QPF AND NAM BUFKIT HINTS AT
SOME SHOWER ACTIVITY UNDER THIS COLDER/CYCLONIC FLOW ALOFT. HELD
ONTO SOME LOWER-END 20-40 POPS TO HONOR THIS SIGNAL. LOOK FOR
CHILLIER THAN NORMAL HIGHS IN THE UPPER 40S TO LOWER 50S AS WELL.
CLEARING THEN EXPECTED FRIDAY NIGHT AS A WEAK RIDGE OF HIGH PRESSURE
DRIFTS ACROSS THE REGION WITH LOWS DIPPING INTO THE UPPER 20S TO
LOWER 30S. WILL HAVE TO KEEP THIS IN MIND FOR POSSIBLE FROST/FREEZE
HEADLINES.
.LONG TERM...SATURDAY THROUGH TUESDAY
330 AM CDT WED APR 18 2012
18.00Z GFS AND ECMWF IN PRETTY GOOD AGREEMENT THROUGH THE LONG TERM.
BOTH MODELS HAVE SATURDAY DRY WITH SURFACE RIDGE HOLDING ACROSS THE
AREA. TEMPERATURES STILL A BIT ON THE COOL SIDE THE THOUGH WITH
HIGHS IN THE LOW-MID 50S. WARM AIR ADVECTION AHEAD OF A WEAK
MID-LEVEL WAVE IN THE NORTHWEST FLOW ALOFT WILL INCREASE CLOUDS AND
PRODUCE A CHANCE OF -SHRA SATURDAY NIGHT. THIS WILL BE MAINLY
NORTHWEST OF A MEDFORD THROUGH WINONA AND DODGE CENTER LINE. THIS
WAVE WILL THEN PRODUCE A CHANCE OF SHRA THROUGH SATURDAY MAINLY EAST
OF THE MISSISSIPPI RIVER. SUNDAY NIGHT THROUGH MONDAY WILL SEE WARM
AIR ADVECTION ACROSS THE AREA WITH HIGHS MONDAY INCREASING INTO THE
UPPER 50S TO MIDDLE 60S. MODELS THEN SHOW A BIT MORE VIGOROUS
MID-LEVEL/SURFACE LOW PUSHING ACROSS SOUTHERN CANADA AND THE
NORTHERN PLAINS...TOWARD THE AREA MONDAY NIGHT THROUGH TUESDAY FOR A
CHANCE OF SHOWERS AND THUNDERSTORMS. LOOK FOR HIGHS ON TUESDAY WELL
INTO THE 60S.
&&
.AVIATION...THROUGH 18Z THURSDAY
1236 PM CDT WED APR 18 2012
GUSTY WINDS WILL CONTINUE THROUGH SUNDOWN THIS EVENING. GUST SPEED
BEHAVIOR WILL BE ERRATIC OVER TIME THIS AFTERNOON WITH MUCH OF IT
DEPENDENT ON MIXING DEPTH. THE DIRECTION SHOULD BE MORE RELIABLE.
A COLD RAIN SYSTEM MOVES IN FOR LATE TONIGHT AND THURSDAY. IFR
CONDITIONS /OR VERY LOW MVFR/ ARE EXPECTED BY AFTERNOON JUST
BEYOND THE TAF TIME AT BOTH SITES IN A MODERATE RAIN. CLOUDS AND
VSBYS WILL SLOWLY LOWER THROUGH THE MORNING INTO THE AFTERNOON.
CONFIDENCE ON THIS WEATHER SYSTEM IS PRETTY HIGH. THERE MAY ALSO
BE EMBEDDED THUNDER WITHIN THE RAIN SHIELD ALTHOUGH THIS WAS NOT
INCLUDED IN THE TAFS AT THIS TIME. WOULD EXPECT A LARGE
PRECIPITATION SHIELD OVER THE REGION THURSDAY WITH THIS WEATHER
SYSTEM TRACKING EAST TO WEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
330 AM CDT WED APR 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM.... DAS
AVIATION...BAUMGARDT
AREA FORECAST DISCUSSION...UPDATED
NWS LA CROSSE WI
710 AM CDT WED APR 18 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
710 AM CDT WED APR 18 2012
UPDATE...HAVE UPDATED THE FORECAST IN REGARD TO THE RAIN SHOWERS
CURRENTLY MOVING ACROSS THE REGION. MUCH OF THE LOW LEVEL MOISTURE
ADVECTION HAS BROUGHT THESE SHOWERS OUT AHEAD OF THE COLD FRONT
WITH MUCH OF THIS SHOWER ACTIVITY INTO CENTRAL WISCONSIN BY LATER
THIS MORNING. SKIES ARE ALSO CLEARING OUT ACROSS MINNESOTA...SO
HAVE GONE WITH A MUCH FASTER END TO THE RAIN THIS
MORNING/AFTERNOON ALONG WITH THE CLOUD TRENDS. HAVE HELD ONTO A
SMALL CHANCE FOR RAIN SHOWERS LATE THIS AFTERNOON FROM SOUTHWEST
WISCONSIN INTO NORTHEAST IOWA FOR THE OFF CHANCE THAT SOME SHOWERS
COULD DEVELOP ALONG THE STALLING OUT FRONT...WHICH IS WHAT THE
PAST FEW RUNS OF THE HRRR HAVE SHOWN. CONFIDENCE IN THOSE SHOWERS
ACTUALLY DEVELOPING AT THIS POINT ARE VERY LOW THOUGH GIVEN THE
ADVANCEMENT OF THIS MORNINGS CONVECTION.
PREVIOUS SHORT TERM AFD...
FIRST CONCERN WILL BE SHOWERS/THUNDERSTORMS TODAY...THEN RAIN AGAIN
THURSDAY INTO THURSDAY NIGHT WITH PERHAPS SOME SNOW MIXING IN
THURSDAY NIGHT. LOOK FOR A CHANCE OF LINGERING RAIN/SHOWERS ON
FRIDAY AS WELL.
CURRENT WATER VAPOR IMAGERY SHOWING A RATHER DYNAMIC MID-LEVEL WAVE
PUSHING INTO WESTERN MN. AT THE SURFACE...LOW PRESSURE WAS LOCATED
OVER SOUTHWEST MN WITH WARM AIR ADVECTION/STRONG ISENTROPIC LIFT AND
MOISTURE TRANSPORT PRODUCING SCATTERED SHRA/TS ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY REGION. SO FAR MOST OF THIS ACTIVITY HAS
BEEN CONFINED ALONG/NORTH OF I-90. MEANWHILE...THE COLD FRONT FROM
THE LOW WAS PRODUCING A DECENT LINE OF THUNDERSTORMS FROM SOUTHWEST
MN INTO NORTHEAST NEB. OTHERWISE...UNDER MOSTLY CLOUDY
SKIES...TEMPERATURES AT 3 AM ACROSS THE AREA WERE IN THE MID 40S TO
MID 50S.
FOR TODAY...WILL BE WATCHING THAT LOW AND COLD FRONT TRACK EAST
ACROSS THE AREA AS THE NAM HAS 0-3KM MUCAPE INCREASING INTO THE
800-1100 J/KG RANGE THIS MORNING AND AFTERNOON. THERE IS ALSO AMPLE
SHEAR PRESENT IN THIS LAYER IN THE 35-40KT RANGE. BUFKIT ALSO
SHOWING MOST OF THIS ACTIVITY FAIRLY HIGH BASED. SO...THINKING THERE
MAY BE AN OUTSIDE CHANCE OF SOME SUB-SEVERE HAIL/WIND WITH A FEW OF
THESE STORMS. HIGHEST THREAT AREA FOR THIS OCCURRING LOOKS TO BE
SOUTHEAST OF A LINE FROM NEAR SPARTA AND VIROQUA WI...TO NEAR
OELWEIN IA. OTHERWISE...LOOK FOR GUSTY SOUTHWEST WINDS THIS MORNING
IN THE 15-30 MPH RANGE SHIFT TO THE WEST/NORTHWEST THIS AFTERNOON
WITH HIGHS TOPPING OFF WELL INTO THE 60S.
FOR TONIGHT...WILL SEE CLEARING EARLY IN THE EVENING WITH THE COLD
FRONT SLIDING SOUTHEAST OF THE AREA AND THEN STALLING OUT ACROSS NORTHERN
IL INTO CENTRAL IA. WEAK CYCLOGENESIS OVER THE CENTRAL PLAINS WILL
THEN PRODUCE ISENTROPIC LIFT/MOISTURE TRANSPORT ACROSS THIS FRONTAL
BOUNDARY FOR INCREASING CLOUDS AGAIN AFTER MIDNIGHT. ANY RAIN LOOKS
LIKE IT WILL HOLD OFF SOUTH/WEST OF THE AREA. INCREASING ISENTROPIC
LIFT/MOISTURE TRANSPORT AHEAD OF THE THE WEAK WAVE OF LOW PRESSURE
OVER THE PLAINS SPREADS RAIN INTO THE AREA ON THURSDAY. NAM STILL
SHOWING SOME WEAK ELEVATED CAPE IN THE 850-700MB LAYER FOR PERHAPS
AN ISOLATED CLAP OR TWO OF THUNDER EMBEDDED IN THE RAIN SHIELD.
OTHERWISE...EASTERLY FLOW AND RAIN WILL MAKE FOR A RATHER RAW DAY
WITH HIGHS STRUGGLING INTO THE UPPER 40S TO MIDDLE 50S.
THE WAVE OF LOW PRESSURE MOVES ACROSS NORTHERN IL THURSDAY
NIGHT..DRAGGING COOLER AIR IN ACROSS THE REGION. THIS IS EXPECTED TO
PRODUCE A COOLING DEFORMATION AREA WITH A PERHAPS A MIX OF A
RAIN/SNOW ACROSS PORTIONS OF THE AREA LATE IN THE NIGHT. NO SNOW
ACCUMULATION IS EXPECTED THOUGH.
ON FRIDAY...THE LOW TRACK EAST INTO THE EASTERN GREAT LAKES REGION
WITH PERHAPS SOME LINGERING DEFORMATION PRECIPITATION IN THE
MORNING. MEANWHILE...THE COOL/RATHER DEEP MID-LEVEL TROUGH TRACKS
OVER OUR AREA DURING THE DAY. THE NAM QPF AND NAM BUFKIT HINTS AT
SOME SHOWER ACTIVITY UNDER THIS COLDER/CYCLONIC FLOW ALOFT. HELD
ONTO SOME LOWER-END 20-40 POPS TO HONOR THIS SIGNAL. LOOK FOR
CHILLIER THAN NORMAL HIGHS IN THE UPPER 40S TO LOWER 50S AS WELL.
CLEARING THEN EXPECTED FRIDAY NIGHT AS A WEAK RIDGE OF HIGH PRESSURE
DRIFTS ACROSS THE REGION WITH LOWS DIPPING INTO THE UPPER 20S TO
LOWER 30S. WILL HAVE TO KEEP THIS IN MIND FOR POSSIBLE FROST/FREEZE
HEADLINES.
.LONG TERM...SATURDAY THROUGH TUESDAY
330 AM CDT WED APR 18 2012
18.00Z GFS AND ECMWF IN PRETTY GOOD AGREEMENT THROUGH THE LONG TERM.
BOTH MODELS HAVE SATURDAY DRY WITH SURFACE RIDGE HOLDING ACROSS THE
AREA. TEMPERATURES STILL A BIT ON THE COOL SIDE THE THOUGH WITH
HIGHS IN THE LOW-MID 50S. WARM AIR ADVECTION AHEAD OF A WEAK
MID-LEVEL WAVE IN THE NORTHWEST FLOW ALOFT WILL INCREASE CLOUDS AND
PRODUCE A CHANCE OF -SHRA SATURDAY NIGHT. THIS WILL BE MAINLY
NORTHWEST OF A MEDFORD THROUGH WINONA AND DODGE CENTER LINE. THIS
WAVE WILL THEN PRODUCE A CHANCE OF SHRA THROUGH SATURDAY MAINLY EAST
OF THE MISSISSIPPI RIVER. SUNDAY NIGHT THROUGH MONDAY WILL SEE WARM
AIR ADVECTION ACROSS THE AREA WITH HIGHS MONDAY INCREASING INTO THE
UPPER 50S TO MIDDLE 60S. MODELS THEN SHOW A BIT MORE VIGOROUS
MID-LEVEL/SURFACE LOW PUSHING ACROSS SOUTHERN CANADA AND THE
NORTHERN PLAINS...TOWARD THE AREA MONDAY NIGHT THROUGH TUESDAY FOR A
CHANCE OF SHOWERS AND THUNDERSTORMS. LOOK FOR HIGHS ON TUESDAY WELL
INTO THE 60S.
&&
.AVIATION...TODAY AND TONIGHT
626 AM CDT WED APR 18 2012
A COLD FRONT MOVING THROUGH THE REGION WILL BRING RAIN AND A FEW
THUNDERSTORMS ON IN AHEAD OF IT. THIS RAIN IS TRACKING EASTWARD A
BIT FASTER THAN THE OVERNIGHT MODELS HAD BEEN PROGGING IT TO GO
EAST WITH THE BACK EDGE APPEARING TO BE THROUGH RST BY 12Z AND
LSE BY 13Z. ANY OF THE BACK SIDE SHOWERS WILL LIFT TO THE
NORTHEAST THIS MORNING ALONG WITH THE MID TO HIGH LEVEL CLOUD
COVER. THUS...EXPECTING A QUICK CLEAR OUT THIS MORNING...THOUGH
WINDS WILL REMAIN RATHER GUSTY FOR A PERIOD BEFORE LIGHTENING UP.
SOME CU MAY FORM THIS AFTERNOON...BUT SHOULD BE VFR AT ABOUT
5-6KFT. AFTER WINDS LIGHTEN AND SKIES CLEAR THIS AFTERNOON AND
TONIGHT...THE NEXT SYSTEM WILL MOVE INTO THE REGION OVERNIGHT AND
BRING HIGH LEVEL CLOUD COVER BACK IN. ANY RAIN SHOULD HOLD OFF
UNTIL AFTER 12Z THOUGH.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
330 AM CDT WED APR 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM.... DAS
AVIATION...HALBACH
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
330 AM CDT WED APR 18 2012
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT
330 AM CDT WED APR 18 2012
FIRST CONCERN WILL BE SHOWERS/THUNDERSTORMS TODAY...THEN RAIN AGAIN
THURSDAY INTO THURSDAY NIGHT WITH PERHAPS SOME SNOW MIXING IN
THURSDAY NIGHT. LOOK FOR A CHANCE OF LINGERING RAIN/SHOWERS ON
FRIDAY AS WELL.
CURRENT WATER VAPOR IMAGERY SHOWING A RATHER DYNAMIC MID-LEVEL WAVE
PUSHING INTO WESTERN MN. AT THE SURFACE...LOW PRESSURE WAS LOCATED
OVER SOUTHWEST MN WITH WARM AIR ADVECTION/STRONG ISENTROPIC LIFT AND
MOISTURE TRANSPORT PRODUCING SCATTERED SHRA/TS ACROSS THE UPPER
MISSISSIPPI RIVER VALLEY REGION. SO FAR MOST OF THIS ACTIVITY HAS
BEEN CONFINED ALONG/NORTH OF I-90. MEANWHILE...THE COLD FRONT FROM
THE LOW WAS PRODUCING A DECENT LINE OF THUNDERSTORMS FROM SOUTHWEST
MN INTO NORTHEAST NEB. OTHERWISE...UNDER MOSTLY CLOUDY
SKIES...TEMPERATURES AT 3 AM ACROSS THE AREA WERE IN THE MID 40S TO
MID 50S.
FOR TODAY...WILL BE WATCHING THAT LOW AND COLD FRONT TRACK EAST
ACROSS THE AREA AS THE NAM HAS 0-3KM MUCAPE INCREASING INTO THE
800-1100 J/KG RANGE THIS MORNING AND AFTERNOON. THERE IS ALSO AMPLE
SHEAR PRESENT IN THIS LAYER IN THE 35-40KT RANGE. BUFKIT ALSO
SHOWING MOST OF THIS ACTIVITY FAIRLY HIGH BASED. SO...THINKING THERE
MAY BE AN OUTSIDE CHANCE OF SOME SUB-SEVERE HAIL/WIND WITH A FEW OF
THESE STORMS. HIGHEST THREAT AREA FOR THIS OCCURRING LOOKS TO BE
SOUTHEAST OF A LINE FROM NEAR SPARTA AND VIROQUA WI...TO NEAR
OELWEIN IA. OTHERWISE...LOOK FOR GUSTY SOUTHWEST WINDS THIS MORNING
IN THE 15-30 MPH RANGE SHIFT TO THE WEST/NORTHWEST THIS AFTERNOON
WITH HIGHS TOPPING OFF WELL INTO THE 60S.
FOR TONIGHT...WILL SEE CLEARING EARLY IN THE EVENING WITH THE COLD
FRONT SLIDING SOUTHEAST OF THE AREA AND THEN STALLING OUT ACROSS NORTHERN
IL INTO CENTRAL IA. WEAK CYCLOGENESIS OVER THE CENTRAL PLAINS WILL
THEN PRODUCE ISENTROPIC LIFT/MOISTURE TRANSPORT ACROSS THIS FRONTAL
BOUNDARY FOR INCREASING CLOUDS AGAIN AFTER MIDNIGHT. ANY RAIN LOOKS
LIKE IT WILL HOLD OFF SOUTH/WEST OF THE AREA. INCREASING ISENTROPIC
LIFT/MOISTURE TRANSPORT AHEAD OF THE THE WEAK WAVE OF LOW PRESSURE
OVER THE PLAINS SPREADS RAIN INTO THE AREA ON THURSDAY. NAM STILL
SHOWING SOME WEAK ELEVATED CAPE IN THE 850-700MB LAYER FOR PERHAPS
AN ISOLATED CLAP OR TWO OF THUNDER EMBEDDED IN THE RAIN SHIELD.
OTHERWISE...EASTERLY FLOW AND RAIN WILL MAKE FOR A RATHER RAW DAY
WITH HIGHS STRUGGLING INTO THE UPPER 40S TO MIDDLE 50S.
THE WAVE OF LOW PRESSURE MOVES ACROSS NORTHERN IL THURSDAY
NIGHT..DRAGGING COOLER AIR IN ACROSS THE REGION. THIS IS EXPECTED TO
PRODUCE A COOLING DEFORMATION AREA WITH A PERHAPS A MIX OF A
RAIN/SNOW ACROSS PORTIONS OF THE AREA LATE IN THE NIGHT. NO SNOW
ACCUMULATION IS EXPECTED THOUGH.
ON FRIDAY...THE LOW TRACK EAST INTO THE EASTERN GREAT LAKES REGION
WITH PERHAPS SOME LINGERING DEFORMATION PRECIPITATION IN THE
MORNING. MEANWHILE...THE COOL/RATHER DEEP MID-LEVEL TROUGH TRACKS
OVER OUR AREA DURING THE DAY. THE NAM QPF AND NAM BUFKIT HINTS AT
SOME SHOWER ACTIVITY UNDER THIS COLDER/CYCLONIC FLOW ALOFT. HELD
ONTO SOME LOWER-END 20-40 POPS TO HONOR THIS SIGNAL. LOOK FOR
CHILLIER THAN NORMAL HIGHS IN THE UPPER 40S TO LOWER 50S AS WELL.
CLEARING THEN EXPECTED FRIDAY NIGHT AS A WEAK RIDGE OF HIGH PRESSURE
DRIFTS ACROSS THE REGION WITH LOWS DIPPING INTO THE UPPER 20S TO
LOWER 30S. WILL HAVE TO KEEP THIS IN MIND FOR POSSIBLE FROST/FREEZE
HEADLINES.
.LONG TERM...SATURDAY THROUGH TUESDAY
330 AM CDT WED APR 18 2012
18.00Z GFS AND ECMWF IN PRETTY GOOD AGREEMENT THROUGH THE LONG TERM.
BOTH MODELS HAVE SATURDAY DRY WITH SURFACE RIDGE HOLDING ACROSS THE
AREA. TEMPERATURES STILL A BIT ON THE COOL SIDE THE THOUGH WITH
HIGHS IN THE LOW-MID 50S. WARM AIR ADVECTION AHEAD OF A WEAK
MID-LEVEL WAVE IN THE NORTHWEST FLOW ALOFT WILL INCREASE CLOUDS AND
PRODUCE A CHANCE OF -SHRA SATURDAY NIGHT. THIS WILL BE MAINLY
NORTHWEST OF A MEDFORD THROUGH WINONA AND DODGE CENTER LINE. THIS
WAVE WILL THEN PRODUCE A CHANCE OF SHRA THROUGH SATURDAY MAINLY EAST
OF THE MISSISSIPPI RIVER. SUNDAY NIGHT THROUGH MONDAY WILL SEE WARM
AIR ADVECTION ACROSS THE AREA WITH HIGHS MONDAY INCREASING INTO THE
UPPER 50S TO MIDDLE 60S. MODELS THEN SHOW A BIT MORE VIGOROUS
MID-LEVEL/SURFACE LOW PUSHING ACROSS SOUTHERN CANADA AND THE
NORTHERN PLAINS...TOWARD THE AREA MONDAY NIGHT THROUGH TUESDAY FOR A
CHANCE OF SHOWERS AND THUNDERSTORMS. LOOK FOR HIGHS ON TUESDAY WELL
INTO THE 60S.
&&
.AVIATION...
1130 PM CDT TUE APR 17 2012
THE SFC PRESSURE GRADIENT WILL TIGHTEN ACROSS THE REGION DURING THE
EARLY MORNING HOURS AS A COLD FRONT APPROACHES FROM THE NORTHERN
PLAINS. LITTLE IF ANY DECOUPLING GOING ON...SO EXPECT INCREASING
WINDS OVERNIGHT...AND WOULD NOT BE SURPRISED IF THERE WAS SOME
GUSTINESS FROM TIME TO TIME. LOOKING FOR A SHIFT FROM SOUTH TO WEST
WITH THE FRONTAL PASSAGE...16-18Z AT KRST AND 19-21Z AT KLSE. IT
SHOULD ALSO BE NOTED THAT THE LOW LEVEL WINDS WILL ALSO BE
STRONG...WITH RUC13/NAM12 BUFKIT SOUNDINGS POINTING TO 19050KT NEAR
1500 FT THROUGH 12Z.
CLOUDS WILL BE ON THE INCREASE...WITH A GRADUAL LOWERING IN THE CIGS
AS THE FRONT NEARS. COULD SEE A FEW HOURS OF MVFR JUST AHEAD OF THE
FRONT.
WHILE THE BEST UPPER LEVEL FORCING WILL STAY NORTH...THE LOW LEVEL
JET/MOISTURE TRANSPORT WAS ALREADY SPARKING -SHRA AHEAD OF THE
FRONT...ALA LATEST 88-D RETURNS. THERE WAS SOME ISOLATED TS ALSO.
THE LATEST HRRR AND NAM12 HAVE SPED THE SYSTEM UP A BIT...AND HAVE
PUSHED UP THE MORE LIKELY PERIODS FOR -SHRA AS A RESULT. HAVE OPTED
TO LEAVE ANY TS OUT FOR NOW AS COVERAGE FOR THUNDER LOOKS SPOTTY AT
THE MOMENT...AND INSTABILITY IS LIMITED THROUGH THE MORNING HOURS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
330 AM CDT WED APR 18 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM... DAS
LONG TERM.... DAS
AVIATION..... RIECK
AREA FORECAST DISCUSSION...UPDATED
NWS LITTLE ROCK AR
1222 AM CDT FRI APR 20 2012
.DISCUSSION...
UPDATED FOR 06Z AVIATION DISCUSSION BELOW...
&&
.AVIATION...
THE SHRA/TSRA ONGOING ALONG COLD FRONT...CURRENTLY LOCATED FROM
SW MO INTO SOUTH CENTRAL OK...WILL MOVE SE INTO NWRN SECTIONS OF
THE STATE THIS MORNING. EXPECT CHANCES OF SHRA/TSRA TO PERSIST
ALONG AND AHEAD OF THIS FRONT AS IT PROGRESSES SE ACROSS THE STATE
THROUGH LATE THIS AFTERNOON. SOME MVFR CONDITIONS WILL BE POSSIBLE
UNDER THIS PRECIP ACTIVITY...WITH LESSER CONDITIONS UNDER STRONGER
THUNDERSTORMS. WINDS WILL SWITCH FROM THE SOUTH TO THE WEST AND NW
BEHIND THE FRONT. SOME GUSTS COULD BE SEEN BEHIND THE FRONT...WITH
GUSTS AROUND 20 KTS POSSIBLE. PRECIP ACTIVITY SHOULD MOVE OUT OF
THE STATE BY FRI EVENING AS THE FRONT MOVES TO THE SE OF AR.
&&
.PREV DISCUSSION... /ISSUED 914 PM CDT THU APR 19 2012/
UPDATE...
JUST SOME MINOR TWEAKS TO THE FORECAST FOR THE OVERNIGHT PERIOD.
SCATTERED THUNDERSTORMS HAVE DEVELOPED ALONG A FRONT IN CENTRAL
OKLAHOMA THIS EVENING...AND EXTEND NORTHEAST TO NEAR TULSA. RAPID
REFRESH RUC GUIDANCE SUGGESTS CONVECTION WILL CONTINUE ALONG THE
FRONT AND WILL EXPAND SOMEWHAT AS IT MOVES TOWARDS ARKANSAS. THIS
WOULD PUT SOME SHOWERS AND ISOLATED TSTMS IN THE NORTHWEST
COUNTIES BY AROUND DAYBREAK. HOWEVER...RUC GUIDANCE SUGGESTS MORE
DOMINANT/WIDESPREAD AREA OF PRECIP WILL APPROACH SOUTHWEST
ARKANSAS A FEW HOURS AFTER DAWN THANKS IN PART TO STRONGER SFC LOW
ALONG THE FRONT IN NE TEXAS. AS SUCH...LOWERED POPS JUST A TAD IN
THE NORTHWEST AFTER 12Z. STILL HAVE HIGH CHANCE VALUES UP
THERE...BUT LEFT THE LIKELY VALUES CONFINED TO AREAS SOUTH OF THE
I-40 CORRIDOR AND WEST OF CLARKSVILLE.
PER THE RUC AND LATEST 12KM NAM GUIDANCE...PRECIP WILL LIKELY
SLACKEN A BIT BETWEEN 12Z-18Z BUT WILL THEN PICK UP IN COVERAGE
AND INTENSITY DURING THE AFTERNOON HOURS. NORTHERN AREAS MAY NOT
SEE MUCH OUTSIDE OF SOME SHORT SPITS OF RAIN OR DRIZZLE FROM MID
TO LATE MORNING IF THE NAM VERIFIES. DECIDED NOT TO TRY AND TIME
SUCH DRY PERIODS THOUGH AND LEFT THE LATE MORNING AND
AFTERNOON/EVENING POP FORECASTS FOR TOMORROW ALONE.
OTHERWISE...FORECAST APPEARS TO BE ON TRACK AND NO OTHER CHANGES
WERE MADE.
PREV DISCUSSION... /ISSUED 240 PM CDT THU APR 19 2012/
SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
HIGH PRES RDG WAS SITUATED JUST E OF THE FA THIS AFTN...WITH A
GENERAL SELY WIND FLOW NOTED. WITH FAIRLY DRY AIR STILL IN PLACE
ACRS THE REGION...ABUNDANT SUNSHINE ALLOWED MID AFTN TEMPS TO CLIMB
INTO THE MID AND UPR 70S. MEANWHILE...LOW PRES CONTD TO DVLP OVR THE
SRN PLAINS AND WL EVENTUALLY AFFECT THE MID SOUTH OVR THE NEXT 24 TO
36 HRS.
MOISTURE LVLS WL START TO INCRS SIGNIFICANTLY FM THE W TNGT AND FRI
AS THE AFOREMENTIONED STORM SYS MOVES CLOSER TO AR. ASSOCD CDFNT
RMNS PROGGED TO ENTER NWRN AR FRI MRNG AND MOVE THRU THE REST OF THE
STATE BY FRI EVENING. A BAND OF MAINLY POST-FNTL SHRA/EMBEDDED TSRA
WL ACCOMPANY THE BNDRY...WITH A GENERAL 1/2 TO ONE INCH OF QPF
EXPECTED. PARTS OF SERN AR COULD SEE LOCALLY HIGHER AMTS.
CANNOT RULE OUT SOME LINGERING RAIN CHCS ACRS PARTS OF FAR SERN AR
EARLY ON SAT. OTHERWISE...NWLY WINDS WL USHER COOLER AND DRIER AIR
INTO THE REGION. TEMPS WL TREND DOWN TO BLW NORMAL LVLS IN THE
COMING DAYS.
LONG TERM...MONDAY THROUGH THURSDAY
RIDGING OVER THE HIGH PLAINS WILL PROVIDE NW UPR FLOW TO THE NATURAL
STATE FOR THE MAJORITY OF THE LONG TERM. THE NW FLOW WILL GRADUALLY
SHIFT EAST BY THURSDAY WHILE AT THE SAME TIME SFC HIGH PRESSURE
DRIFTS EAST OF THE STATE. THIS WILL ALLOW AN OVERALL WARMING TREND
THROUGH THE PD AS SRLY LOW LVL FLOW DEVELOPS.
OVERALL...VERY FEW CHANGES WERE MADE TO THE FCST AS PREDOMINATELY
DRY CONDS ARE EXPECTED. HOWEVER...GIVEN THAT NW UPR FLOW CAN AT
TIMES SURPRISE US WITH UNEXPECTED CLOUDS OR PRECIP DUE TO MODEL
UNDERFORECAST SHRTWVS...HAVE INCREASED CLOUD COVER FOR MUCH OF THE
MIDDLE PART OF THE WEEK GIVEN A FEW SHRTWVS DIVING INTO THE UPR
TROUGH.
&&
.PRELIMINARY POINT TEMPS/POPS...
BATESVILLE AR 44 63 43 72 / 50 10 0 0
CAMDEN AR 50 68 47 75 / 60 10 0 0
HARRISON AR 39 63 42 70 / 20 0 0 0
HOT SPRINGS AR 48 66 44 75 / 40 0 0 0
LITTLE ROCK AR 48 67 47 73 / 50 10 0 0
MONTICELLO AR 51 67 48 73 / 60 10 0 0
MOUNT IDA AR 47 66 43 75 / 30 0 0 0
MOUNTAIN HOME AR 40 64 42 71 / 20 0 0 0
NEWPORT AR 46 64 46 72 / 50 10 0 0
PINE BLUFF AR 50 66 47 73 / 60 10 0 0
RUSSELLVILLE AR 44 67 44 74 / 30 0 0 0
SEARCY AR 47 65 46 72 / 50 10 0 0
STUTTGART AR 49 66 48 73 / 60 10 0 0
&&
.LZK WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
AVIATION...62
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
319 AM MDT FRI APR 20 2012
.SHORT TERM...INCREASING MID LEVEL QG DESCENT WILL BE OVER THE
CWFA THIS MORNING AS THE UPPER LEVEL JET SHIFTS TO THE EAST.
LINGERING SHOWERS OVER THE NORTHEAST PLAINS THIS MORNING ARE JET
INDUCED. THE HRRR AND RUC13 MDLS KILL OFF THE SHOWERS IN THE
12-15Z TIME FRAME SO WILL TREND THE FCST THAT WAY AS WELL. SOME
STRATUS HAS DEVELOPED AROUND THE DENVER AREA THIS MORNING
FOLLOWING THE FRONTAL PASSAGE. NOT MUCH IMMEDIATELY UPSTREAM SO DO
NOT EXPECT THE STRATUS TO LINGER FOR VERY LONG...SHUD SEE THE LOW
CLOUD LAYER START TO DECREASE AFTER 12Z. THERE WILL BE SOME
CLEARING LATER THIS MORNING BUT ENUF WEAK INSTBY THIS AFTERNOON
FOR CONVECTIVE CLOUD COVER TO REDEVELOP. WL GO WITH PRIMARILY
PARTLY CLOUDY FCST TODAY. SPATIAL CROSS-SECTIONS AND SIMULATED
STLT PRODUCTS APPEAR TO SUPPORT THIS THROUGH EARLY THIS EVENING.
CLEARING OVERNIGHT EXPECTED WITH SOME OCCASIONSL GUSTY DOWNSLOPE
WINDS ALONG THE FRONT RANGE FOOTHILLS OVERNIGHT
.LONG TERM...AN UPPER LEVEL RIDGE WILL BE OVER THE AREA THRU THE
WEEKEND. THIS WILL LEAD TO MAINLY DRY CONDITIONS WITH ABV NORMAL
TEMPS. SOME MOISTURE MAY MOVE INTO THE MTNS ON SUN SO WILL MENTION
SOME ISOLD LATE AFTN/EVENING TSTMS OVER THE HIGHER TERRAIN. HIGHS
BOTH DAYS OVER NERN CO WILL BE IN THE 70S.
THE UPPER LEVEL RIDGE WILL REMAIN OVER THE AREA MON AND TUE
WITH CROSS-SECTIONS SHOWING LIMITED MOISTURE. ONCE AGAIN COULD SEE
SOME ISOLD CONVECTION OVER THE HIGHER TERRAIN IN THE LATE
AFTN/EARLY EVENING HOURS. HIGHS WILL REMAIN ABV NORMAL BOTH DAYS WITH
HIGHS POSSIBLY REACHING THE LOWER TO MID 80S ACROSS NERN CO BY
TUE.
FOR WED AND THU THERE IS NOT MUCH AGREEMENT BETWEEN THE ECMWF AND
THE GFS. THE ECMWF KEEPS A FLAT RIDGE OVER THE AREA WHILE THE GFS
SHOWS AN UPPER LEVEL LOW MOVING ACROSS SRN CO LATE WED INTO THU.
THE CANADIAN MODEL IS MORE IN LINE WITH THE ECMWF SO WILL TREND
FCST MORE TOWARDS THE ECMWF. THE ECMWF SHOWS A WK FNT MAY MOVE
INTO NERN CO ON WED WITH SOME INCREASE IN MOISTURE AS A WK
DISTURBANCE TRACKS ACROSS NRN CO BY WED AFTN OR NIGHT. THUS COULD
SEE AT LEAST A SLIGHT CHC OF AFTN/EVENING CONVECTION OVER NRN CO.
TEMPS ON WED MAY COOL DOWN BACK DOWN INTO THE 70S ACROSS NERN CO
BEHIND WK FNT. ON THU THE ECMWF STILL SHOWS ENOUGH MOISTURE AROUND
FOR A SLIGHT CHC OF AFN/EVENING CONVECTION OVER NRN CO WITH LITTLE
CHANGE TO TEMPS.
&&
.AVIATION...IFR/MVFR CIGS AROUND DENVER SHOULD START TO LIFT BY
12Z WITH VFR CONDITIONS AFTER 15Z. NORTHERLY WINDS THIS MORNING
WILL DECREASE AND BECOME MORE VARIABLE BY 15Z. AFTER 18Z WILL KEEP
THE MENTION OF AN E-SELY WIND IN THE TAFS FOR KDEN AND KAPA...
WITH A WEAK W-NWLY OR VRBL SFC WIND AT KBJC.
&&
.HYDROLOGY...NO PRECIPITATION IS EXPECTED FOR THE FOUR MILE
CANYON AREA TODAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...COOPER
LONG TERM....RPK
AVIATION...COOPER
AREA FORECAST DISCUSSION
NWS LINCOLN IL
309 AM CDT FRI APR 20 2012
.DISCUSSION...
ISSUED 309 AM CDT FRI APR 20 2012
SHORT TERM...TODAY THROUGH SUNDAY
COLD FRONT WILL PUSH EASTWARD ACROSS THE AREA TODAY...ACCOMPANIED
BY A BAND OF LIGHT SHOWERS. 00Z UPPER AIR ANALYSIS SHOWS LIMITED
MOISTURE FOR THE FRONT TO WORK WITH...WITH ONLY A NARROW RIBBON OF
5-10C 850MB DEWPOINTS EXTENDING FROM TEXAS NORTHEASTWARD INTO
IOWA. IN ADDITION...00Z KILX AND KDVN UPPER AIR SOUNDINGS FEATURED
A VERY DRY LOW-LEVEL AIRMASS BELOW 600MB. HRRR AND 4KM WRF-NMM
BOTH SUGGEST THE BAND OF SHOWERS WILL GRADUALLY DISSIPATE AS IT
WORKS ITS WAY INTO THE DRIER ENVIRONMENT ACROSS CENTRAL ILLINOIS
THIS MORNING. LATEST RADAR MOSAIC CONTINUES TO INDICATE A WEAKENING
TREND...WHILE IR SATELLITE SHOWS WARMING CLOUD TOPS. END RESULT
WILL BE A BRIEF PERIOD OF SCATTERED SHOWERS ALONG AND IMMEDIATELY
BEHIND THE FRONT. RAINFALL TOTALS WILL REMAIN LIGHT...GENERALLY
UNDER ONE TENTH OF AN INCH. ONCE THE FRONT PASSES...BREEZY AND
COOLER CONDITIONS WILL SPILL INTO THE REGION LATER THIS MORNING
INTO THE AFTERNOON. WITH OVERCAST CONDITIONS AND NORTHWESTERLY
WINDS GUSTING TO 25 MPH AT TIMES...TEMPS WILL HOVER IN THE LOWER
TO MIDDLE 50S BEHIND THE FRONT.
EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY WILL ENSURE MOSTLY
CLOUDY CONDITIONS THROUGH EARLY EVENING...WITH CLEARING SKIES
DEVELOPING ACROSS THE ILLINOIS RIVER VALLEY TOWARD MIDNIGHT...THEN
FURTHER EAST ACROSS THE REMAINDER OF THE AREA OVERNIGHT. PATCHY
FROST WILL BE POSSIBLE ALONG AND NORTHWEST OF A RUSHVILLE TO
BLOOMINGTON-NORMAL LINE...WHERE SKIES WILL CLEAR EARLIEST AND
WINDS WILL DIMINISH TO LESS THAN 5 MPH. OVERNIGHT LOWS WILL RANGE
FROM THE MIDDLE 30S NORTHWEST...TO THE LOWER 40S FAR SOUTHEAST.
COOL/DRY WEATHER WILL BE ON TAP FOR SATURDAY...WITH HIGHS ONLY
REACHING THE MIDDLE TO UPPER 50S. LOW TEMPS SATURDAY NIGHT WILL
LIKELY BE A COUPLE OF DEGREES WARMER THAN TONIGHT DUE TO CLOUD
COVER FROM AN APPROACHING UPPER-LEVEL DISTURBANCE...SO CHANCES FOR
FROST WILL BE REDUCED. IN FACT...MODELS ARE TRYING TO SQUEEZE OUT
SOME LIGHT QPF WITH THE APPROACHING WAVE...HOWEVER THINK AIRMASS
WILL BE TOO DRY TO SUPPORT MEASURABLE PRECIP...SO HAVE MAINTAINED A
DRY FORECAST.
LONG TERM...MONDAY THROUGH THURSDAY
DEEP UPPER LOW IS EXPECTED TO DEVELOP OVER THE EASTERN CONUS EARLY
NEXT WEEK...WITH MODELS STILL VARYING ON ITS EVENTUAL DEPARTURE.
GIVEN HIGHLY AMPLIFIED NATURE OF THE FLOW...THINK SLOWER IS THE
WAY TO GO. END RESULT WILL BE COOL/DRY WEATHER THROUGH AT LEAST
TUESDAY...WITH A MARKED WARMING TREND BEGINNING BY THE MIDDLE OF
THE WEEK AS UPPER HEIGHTS BEGIN TO RISE. HIGH TEMPS WILL START OUT
IN THE LOWER 60S ON MONDAY...THEN WILL CLIMB WELL INTO THE 70S BY
WEDNESDAY AND THURSDAY. RAIN CHANCES THROUGH THE PERIOD APPEAR TO
BE RATHER MINIMAL...WITH THE BEST SHOT AT PRECIP OCCURRING ON
WEDNESDAY AS WARMER AIRMASS BEGINS TO MAKE ITS RETURN.
BARNES
&&
.AVIATION...
ISSUED 1154 PM CDT THU APR 19 2012...FOR THE 06Z TAFS
THE SURFACE LOW HAS ENTERED FAR NW IL...WITH THE COLD FRONT ALONG
THE IL BORDER AND INTO EASTERN MISSOURI. SHOWERS ARE MAINLY IN A
NARROW LINE EXTENDING ALONG THE BEHIND THE FRONT FOR 20-30 MILES.
OVERALL...OUR WINDOW OF CHANCE FOR MEASURABLE RAIN AT ANY TAF SITE
LOOKS TO BE AROUND 3-4 HOURS AT MOST. WE DECIDED TO STILL INCLUDE
SOME PREVAILING RAIN AT ALL SITES AT SOME POINT BETWEEN 07Z AT PIA AND
14Z AT CMI. IT NOW APPEARS LIKELY THAT IFR CONDITIONS WILL DEVELOP
FOR AT LEAST A COUPLE HOURS BEHIND THE FRONT. 500-600FT CIGS HAVE
DEVELOPED ACROSS E IOWA/E MO...AND THAT LOW STRATUS SHOULD
PROGRESS EASTWARD ACROSS C IL LATER TONIGHT AND INTO FRIDAY
MORNING. DAYTIME MIXING AND POST FRONTAL SUBSIDENCE SHOULD HELP TO
MIX DRIER AIR TOWARD THE SURFACE TO RAISE LIFTED CONDENSATION
LEVELS /LCL/ TO AT LEAST MVFR.
WINDS WILL BE ON A NEARLY CONTINUOUS CHANGE THE REST OF THE NIGHT
AND FRIDAY MORNING...AS THEY SHIFT FROM SOUTHERLY TO SW...THEN TO
W-NW AFTER THE FRONT...WITH NORTH WINDS BY LATER AFTERNOON FRIDAY.
VFR CONDITIONS ARE EXPECTED TO DEVELOP FRI EVE FROM WEST TO
EAST...BUT CMI/DEC MAY NOT RAISE ABOVE MVFR BEFORE 06Z.
SHIMON
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
345 AM CDT FRI APR 20 2012
.SYNOPSIS...
06Z SFC ANALYSIS HAS THE LOW JUST SOUTHEAST OF THE QUAD CITIES WITH
A WARM FRONT EAST TO THE SOUTH SUBURBS OF CHICAGO. THE COLD FRONT
RAN INTO SOUTHWEST MISSOURI. DEW POINTS AROUND THE FRONTS WERE IN
THE 50S WITH MAINLY 40S OVER MOST OF THE PLAINS AND MIDWEST. DEW
POINTS IN THE 30S WERE IN THE UPPER MIDWEST AND WESTERN GREAT LAKES.
RADAR TRENDS THE PAST SEVERAL HOURS SHOW A BACK EDGE OF THE MORE
SUBSTANTIAL PRECIPITATION FROM ROUGHLY KRFD TO KUIN. SFC OBS
REPORTED DZ OR VERY LIGHT RAIN BACK INTO EASTERN AND CENTRAL IOWA.
&&
.SHORT TERM...TODAY AND TONIGHT
RUC TRENDS WITH CONDENSATION PRESSURE DEFICITS HAVE BEEN USEFUL IN
DEPICTING PRECIPITATION TRENDS AND WERE USED FOR THE IMMEDIATE SHORT
TERM.
BASED ON RADAR AND RUC TRENDS...ANY MEASURABLE PRECIPITATION SHOULD
BE ACROSS THE FAR EAST AND SOUTHEAST PARTS OF THE CWFA AT 12Z. THE
REMAINDER OF THE AREA SHOULD SEE DRIZZLE/SPRINKLES DUE TO LOW
CONDENSATION PRESSURE DEFICITS COMBINED WITH FORCING AND F VECTOR
CONVERGENCE THROUGH MID MORNING. AS CONDENSATION PRESSURE DEFICITS
RISE THE PRECIPITATION WILL END FROM WEST TO EAST FROM LATE MORNING
THROUGH MID DAY.
CLOUD COVER AND INITIAL PRECIPITATION THIS MORNING WILL HOLD
TEMPERATURES DOWN BUT CLEARING DURING THE MID TO LATE AFTERNOON FROM
WEST TO EAST SHOULD ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MID
50S.
TONIGHT...QUIET AND CHILLY CONDITIONS WILL BE SEEN ACROSS THE AREA.
HIGH PRESSURE OVER THE AREA WILL ALLOW WINDS TO BECOME LIGHT WITH
FROST POSSIBLE. THE POSSIBILITY DOES EXIST THAT A FREEZE MAY OCCUR
ACROSS ABOUT THE NORTHERN QUARTER TO THIRD OF THE CWFA. HOWEVER...
THE MODELS ARE SHOWING INCREASES IN MOISTURE ALOFT AFTER MIDNIGHT
SUGGESTING CI/CS MOVING INTO THE AREA. IF THIS OCCURS TEMPERATURES
WOULD BE HELD UP...POSSIBLY ABOVE FREEZING.
GIVEN THIS UNCERTAINTY...ANY DECISION REGARDING FROST/FREEZE
HEADLINES WILL BE DEFERRED TO THE NEXT SHIFT. ..08..
.LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
OUR NEXT PRECIPITATION CHANCES COME ON SATURDAY AND SATURDAY
NIGHT AS A WEAK SHORTWAVE WITH A WING OF WARM AIR ADVECTION AND
ISENTROPIC LIFT AHEAD OF THE SHORTWAVE. THERE IS JUST ENOUGH
MOISTURE FOR THIS TO SQUEEZE OUT SOME SHOWERS...THOUGH MODELS ARE
SHOWING SOME DIFFERENCES WITH THIS RELATIVELY WEAK FEATURE. NAM
IS THE ODD MODEL OUT THIS MORNING...AS IT IS FARTHER EAST AND
SLIGHTLY WEAKER THAN THE OTHER MODELS HAVE. HAVE IN GENERAL TRIED
TO FOLLOW A BLEND OF THE GFS/ECMWF/UKMET SOLUTIONS ON THIS
FEATURE. WHILE THE MID LEVEL CONVERGENCE SEEMS TO LINGER ON SUNDAY
AND SUNDAY NIGHT...IT DOES NOT APPEAR THAT THERE IS ENOUGH
MOISTURE TO GET ANY SHOWERS GOING AGAIN ON SUNDAY. FOR NOW THE
TIME RANGE WITH THE HIGHEST POTENTIAL FOR PRECIPITATION IS
SATURDAY NIGHT. TEMPERATURES TO BE A LITTLE COOLER ON SATURDAY
WITH THE BAND OF PRECIPITATION MOVING INTO THE AREA...BUT
GRADUALLY WARM FOR SUNDAY AS THE MID LEVEL WARM AIR ADVECTION SETS
BACK IN QUICKLY BEHIND THE SHORTWAVE.
WE REMAIN IN STRONG NORTHWEST FLOW ON MONDAY THROUGH AT LEAST
WEDNESDAY...WITH STRONGLY AMPLIFIED FLOW OVER THE CONUS...WITH THE
DEEP TROUGH OVER THE EAST AND STRONG RIDGE OUT WEST. IT IS
DIFFICULT TO GET A GULF FEED FROM A SOUTHWEST LOW LEVEL FEED OUT OF
THIS TYPE OF SYSTEM...SO MOST SYSTEMS ARE GOING TO HAVE TO DRAG IN
THEIR OWN MOISTURE FROM THE PACIFIC...AND THEN MAKE THEIR WAY OVER
THE RIDGE. TUESDAY AND WEDNESDAY HAVE ANOTHER CHANCE FOR
PRECIPITATION AS WE GET A SLIGHTLY STRONGER SHORTWAVE THROUGH HERE.
SOME MODELS ARE EVEN BRINGING A SURFACE LOW ACROSS THE REGION.
OTHERS SIMPLY SETTLE A TROUGH AXIS ACROSS THE AREA. TOUGH CALL FOR
NOW...AND HAVE MAINTAINED SLIGHT CHANCE OR EVEN LOW CHANCE POP FOR
THE SOUTHERN PORTIONS OF THE FORECAST AREA. AS MOISTURE IS A
LIMITING FACTOR FOR THIS STORM...DO NOT ANTICIPATE HAVING ENOUGH
MOISTURE TO ACT UPON...NOR CAN WE EXPECT A REINFORCING SYSTEM TO
MOVE THROUGH LATER ON IN THE EVENING. ..LE..
&&
.AVIATION...
LIFR TO BORDERLINE MVFR CONDITIONS WILL BE SEEN THROUGH 18Z/20 WITH
CONDITIONS SLOWLY IMPROVING TO VFR. DZ OR SPRINKLES IS EXPECTED AT
ALL TAF SITES THROUGH 18Z/20 BEFORE ENDING. LIGHT WINDS AFT SUNSET
MAY RESULT IN FROST ON NON HANGARED ACFT AFT 06Z/21. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
333 AM CDT FRI APR 20 2012
.SYNOPSIS...
ISSUED AT 331 AM CDT FRI APR 20 2012
A LARGE TROUGH ACROSS THE CENTRAL PLAINS STATES WAS OBSERVED ON LAST
EVENING`S 00 UTC OBJECTIVE ANALYSIS. ALTHOUGH SOME RESPECTABLE
MOISTURE WAS PRESENT IN THE MID LEVELS, THE LOWER TO MIDDLE
TROPOSPHERE WAS QUITE DRY AS NOTED BY THE DRY INTRUSION ON THE 00
UTC KDDC SOUNDING. A NORTHERLY JET STREAK WAS CROSSING THE ROCKIES.
AT THE LEADING EDGE OF THIS JET STREAK WAS SOME ENHANCED CLOUD COVER
AND SCATTERED SHOWERS ASSOCIATED WITH THE FRONT LEFT UPPER DIVERGENT
FEATURE OF THE JET OVER WESTERN NEBRASKA AND NORTHWEST KANSAS.
SURFACE HIGH PRESSURE WAS ALSO SLIDING SOUTHWARD FROM THE NORTHERN
HIGH PLAINS, IN AN AIRMASS THAT SAW TEMPERATURES DIPPING INTO THE
40S ACROSS JUST ABOUT ALL OF WESTERN KANSAS.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 331 AM CDT FRI APR 20 2012
CHANCES FOR LIGHT RAIN SHOWERS WILL DWINDLE TO NEAR NONEXISTENT AS
WE HEAD INTO THIS MORNING. THE FOCUSING MECHANISM WILL BE FATHER TO
THE EAST AND DEEP NORTHWEST FLOW WILL BECOME QUICKLY ESTABLISHED
OVER WESTERN KANSAS BY AROUND 15 UTC. AT THE SURFACE, NORTHERLY FLOW
WILL PERSIST THROUGH THE DAY AS SURFACE HIGH PRESSURE MOVES THROUGH
THE MISSOURI RIVER BASIN. AS WESTERN KANSAS ENDS UP ON THE WESTERN
DIES OF THE UPPER JET, PLENTY OS INSOLATION WILL BE AVAILABLE TODAY
AND TEMPERATURES WOULD WARM NICELY INTO THE 60S. THE ONLY CAVEAT
WILL BE TO WHAT EXTENT LOW STRATUS AFFECTS THE AREA IF AT ALL,
THROUGH THE MIDDLE MORNING. THERE WILL BE SOME SLIGHTLY DRIER AIR
ADVECTING INTO THE AREA, BUT THERE IS NOT A SIGNIFICANT AIRMASS
CHANGE TODAY AS THE FRONT THAT PASSED YESTERDAY MORNING REMAINS THE
FOCUS FOR THUNDERSTORMS OVER EASTERN OKLAHOMA. WINDS ARE GENERALLY
EXPECTED IN THE 10 TO 20 MPH RANGE THROUGH THE AFTERNOON. WESTERN
KANSAS ENDS UP FARTHER UNDER THE SURFACE RIDGE TONIGHT AS WINDS BACK
TO THE SOUTH AND BECOME LIGHT SOUTHWEST BY EARLY SATURDAY MORNING.
DEW POINTS IN THE UPPER 30S AND LOW 40S APPEAR HIGH ENOUGH THAT
SUFFICIENT COOLING FOR FROST IS NOT LIKELY.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 246 AM CDT FRI APR 20 2012
AS THE EXTENDED FORECAST PERIOD STARTS OUT ON SATURDAY MORNING,
CLEAR SKIES, LIGHT SOUTHWEST WINDS AND COOL TEMPERATURES IN THE
UPPER 30S NORTH TO AROUND 40 DEGREES SOUTH CAN BE EXPECTED.
SATURDAY WILL SEE A SURFACE TROUGH MOVE ACROSS MOST OF THE CWA
AND WINDS WILL SHIFT TO THE NORTHWEST DURING SATURDAY AFTERNOON. A
FEW CIRRUS CLOUDS MAY PASS OVERHEAD IN THE NORTHERN CWA LATE
SATURDAY, BUT WILL NOT HAVE ANY SIGNIFICANT INFLUENCE ON MAX
TEMPS. HIGHS ON SATURDAY WILL BE IN THE MID 70S IN THE OUR NORTH
AND RANGE TO THE UPPER 70S IN OUR SOUTHWESTERN CWA. A LARGE UPPER
LEVEL HIGH PRESSURE SYSTEM WILL BEGIN TO BUILD OVER THE 4-CORNERS
AREA SUNDAY, AND THIS WILL ALLOW A SURFACE WARM FRONT TO PUSH
THROUGH WESTERN KANSAS SUNDAY INTO TUESDAY. MIN TEMPS SUNDAY
SHOULD BE IN THE MID 40S TO LOWER 50S, FOLLOWED BY HIGHS ON SUNDAY
IN THE UPPER 70S TO LOWER 80S. THEN ON MONDAY WE WILL BE WITHIN
THE WARM SECTOR OF THE WARM FRONT, ALLOWING SUNNY SKIES AND SOUTH
WINDS TO EVOLVE BY THE AFTERNOON. ONE OR BOTH MONDAY OR TUESDAY
AFTERNOON`S COULD BECOME BREEZY. MAX TEMPS MONDAY WILL TOP OUT IN
THE MID 70S TO NEAR 80 DEGREES. LOWS FOR BOTH TUESDAY AND
WEDNESDAY MORNINGS WILL BE IN THE MID TO UPPER 50S, AND WILL BE
VERY SIMILAR FOR THURSDAY AND FRIDAY. MAXIMUM TEMPERATURES FOR THE
TUESDAY THROUGH THURSDAY PERIOD WILL BE WARM, GENERALLY IN THE MID
TO UPPER 80S. A SOUTHERLY LOW LEVEL FLOW WILL EXIST TUESDAY
THROUGH THURSDAY, WITH MODEL PROGGED TEMPS IN THE 16C TO 24C RANGE
DURING THE AFTERNOONS.
BASICALLY, I SIMPLY LOADED THE CREXTENDFCST_INIT PROCEDURE AND WENT
WITH THOSE GRIDS. THERE WAS A SMALL BULLSEYE OF 20 PERCENT POPS
IN OUR SOUTHEASTERN CWA FOR THURSDAY, BUT I REDUCED THOSE POPS TO
LESS THAN 15 PERCENT AS THE MODELS DID NOT SUPPORT ANY RAIN THEN.
THUS, THE FORECAST WILL BE DRY SATURDAY THROUGH THURSDAY. STRONG
HIGH PRESSURE ANCHORED TO OUR WEST WILL DOMINATE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1242 AM CDT FRI APR 20 2012
WHAT APPEARS TO BE A SLOWLY EXPANDING AREA OF MVFR STRATUS IS MOVING
SOUTHWESTWARD FROM NORTH CENTRAL KANSAS AT THIS TIME. THE SURFACE
OBSERVATIONS INDICATE THE REGION REMAINS IN A WEAK NORTHEAST SURFACE
FLOW. THE RUC CEILING CLOUD FORECAST ARE INDICATING THIS AREA WOULD
EXPAND ACROSS THE LARGER PORTION OF WEST CENTRAL KANSAS BY AROUND 8
OR 9 UTC AS THE SURFACE HIGH PRESSURE RIDGE BUILDS OVER THE AREA.
THIS SOLUTION SEEMS REASONABLE GIVEN THE UPPER THICK CLOUD COVER
APPEARS SCATTERED AT BEST AND ADDITIONAL COOLING IS LIKELY. WE HAVE
RELATIVELY LOW CONFIDENCE IN HOW THE STRATUS FIELD WILL EVOLVE
OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 39 76 49 / 20 0 0 0
GCK 67 40 77 47 / 10 0 0 0
EHA 68 41 79 50 / 10 0 0 0
LBL 68 40 78 51 / 10 0 0 0
HYS 64 38 76 47 / 10 0 0 0
P28 66 41 75 49 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RUSSELL
SHORT TERM...RUSSELL
LONG TERM...BURKE
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
253 AM CDT FRI APR 20 2012
...UPDATED THE EXTENDED DISCUSSION...
.SYNOPSIS...
ISSUED AT 1219 PM CDT THU APR 19 2012
UPPER AIR ANALYSIS AT 12Z THURSDAY INDICATED AN UPPER LEVEL JET
EXTENDED FROM WASHINGTON STATE SOUTHEAST INTO NORTHEASTERN
NEVADA. NEAR THE LEFT EXIT REGION OF THIS JET A -26 TO -28C 500MB
THERMAL TROUGH WAS LOCATED OVER MONTANA. 40 TO 50 METER HEIGHT
FALLS WERE ALSO OBSERVED AT RAPID CITY SOUTH DAKOTA AND DENVER
COLORADO WHILE ACROSS ALONG THE PACIFIC NORTHWEST 50 TO 70 METER
HEIGHT RISES WERE OCCURRING. IN THE CENTRAL PLAINS AT 12Z THURSDAY
BOTH THE 850MB AND 700MB LEVELS INDICATED AN AREA OF MOISTURE WAS
LOCATED NEAR A 850-700MB BAROCLINIC ZONE THAT EXTENDED FROM
NORTHEAST COLORADO INTO CENTRAL NEBRASKA. AT 13Z A SURFACE A COLD
FRONT EXTENDED FROM JUST WEST OF HAYS SOUTH ACROSS THE DODGE CITY
AREA INTO THE PANHANDLE OF TEXAS AND OKLAHOMA.
&&
.UPDATE...
ISSUED AT 1134 PM CDT THU APR 19 2012
INFRARED SATELLITE IMAGERY AS WELL A REGIONAL RADAR AND METAR
OBSERVATIONS SHOW A PICTURE THIS EVENING OF SHOWERS BEING ABLE TO
MAKE PRECIPITATION REACH THE GROUND ACROSS WESTERN NEBRASKA AND
NORTHEAST COLORADO. THAT REGION WILL BE BEST CENTERED IN THE LEFT
FRONT QUADRANT OF THE UPPER LEVEL JET AS IT DIVES SOUTH OVERNIGHT.
A PERUSAL OF THE MODELS, INCLUDING THE LATEST ARW-WRF/NMM-WRF FOCUS
PRECIPITATION CHANCES WITH A COMPACT AREA OF LIFT PROBABLY
ASSOCIATED WITH THE THERMALLY INDIRECT TRANSVERSE CIRCULATION THAT
REMAINS BETTER TIED TO NORTHWEST KANSAS. ADDITIONALLY THE LAST FEW
HOURS, IT APPEAR THAT THE NAM AND OTHER MODELS HAVE SIGNIFICANTLY
OVER FORECAST THE QPF SO FAR THIS EVENING, PERHAPS OWING TO THE
NOTICEABLE DRY LAYER BETWEEN 800 AND 600 MB ON THE 00 UTC KDDC
SOUNDING. AS A RESULT, WE`LL CONTINUE THE THE DOWNTREND ON
PROBABILITIES FOR MEASURABLE PRECIPITATION OVERNIGHT WITH LESS THAN 20
PERCENT AREAL COVERAGE FOR SHOWERS, AS WEAK HIGH PRESSURE
CONTINUES TO SETTLE ACROSS THE AREA OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 152 PM CDT THU APR 19 2012
12Z NAM AND GFS REMAINS FAIRLY CONSISTENT WITH PREVIOUS RUNS IN
DEVELOPING CONVECTION LATE THIS AFTERNOON OVER THE HIGHER TERRAIN
OF COLORADO AS AN UPPER LEVEL JET APPROACHES THE ROCKIES. ANOTHER
AREA OF LATE DAY CONVECTION WILL ALSO BE POSSIBLE NEAR A COLD
FRONT WHICH WAS CROSSING SOUTH CENTRAL KANSAS AS OF 18Z. AT THIS
TIME IT APPEARS BASED ON THE HRRR AND NAM THIS FRONT WILL BE EAST
OF THE PRATT AND MEDICINE LODGE AREAS BY 00Z SO ANY PRECIPITATION
THAT WILL DEVELOP ALONG THIS BOUNDARY IS GOING TO OCCUR EAST OF
THESE LOCATIONS. FURTHER WEST BEHIND THIS FRONT THERE WILL STILL BE
SOME WEAK MID LEVEL INSTABILITY BASED ON MODEL SOUNDINGS EARLY
TONIGHT AND THE NAM EVEN GENERATES SOME VERY LIGHT QPF IN THIS AREA
OF INSTABILITY. AT THIS TIME GIVEN THE DRY AIR FORECAST BELOW THE
800MB LEVEL AM THINKING ONLY CLOUDS AND POSSIBLY VIRGA BUT WILL
CONTINUE TO MONITOR THIS AND ADJUST AS NEEDED FOR THE FIRST FEW
HOURS OF THE EVENING PERIOD.
CONVECTION DEVELOPING FURTHER WEST NEAR THE LEFT EXIT REGION OF
AN UPPER LEVEL JET APPEAR TO STAY WEST OF THE COLORADO BORDER
THROUGH 00Z. THESE STORMS ARE THEN FORECAST TO SPREAD EAST INTO
WESTERN KANSAS OVERNIGHT AS A 500MB THERMAL THROUGH WHICH WAS
LOCATED IN MONTANA AT 12Z THURSDAY MOVES SOUTHEAST INTO WESTERN
KANSAS. TRACK OF THIS UPPER TROUGH SUGGESTS PRECIPITATION CHANCES
WILL CONTINUE THROUGH EARLY FRIDAY AFTERNOON...ESPECIALLY EAST OF
HIGHWAY 283. THE PREVIOUS FORECAST HAS A DECENT HANDLE ON THE
EVOLUTION OF THIS PRECIPITATION SPREADING EAST ACROSS WESTERN
KANSAS LATER TONIGHT AND EARLY FRIDAY SO WILL STAY CLOSE TO THE
PREVIOUS TREND. DID HOWEVER POSTPONE THE ONSET OF THE
PRECIPITATION ACROSS THE FAR WEST UNTIL AFTER 00Z.
AS THE PRECIPITATION ENDS FROM WEST TO EAST THE SKIES ARE
EXPECTED TO CLEAR AS SUBSIDENCE DEVELOPS BEHIND THE UPPER LEVEL
TROUGH. BASED ON THE 18Z FRIDAY AND 00Z SATURDAY 925-950M
TEMPERATURES AND CLEARING SKIES WILL CONTINUE TO FAVOR HIGHS IN
THE MID 60S ACROSS MUCH OF WESTERN KANSAS. FURTHER EAST UPPER 50S
TO LOWER 60S APPEAR MORE REASONABLE.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 246 AM CDT FRI APR 20 2012
AS THE EXTENDED FORECAST PERIOD STARTS OUT ON SATURDAY MORNING,
CLEAR SKIES, LIGHT SOUTHWEST WINDS AND COOL TEMPERATURES IN THE
UPPER 30S NORTH TO AROUND 40 DEGREES SOUTH CAN BE EXPECTED.
SATURDAY WILL SEE A SURFACE TROUGH MOVE ACROSS MOST OF THE CWA
AND WINDS WILL SHIFT TO THE NORTHWEST DURING SATURDAY AFTERNOON. A
FEW CIRRUS CLOUDS MAY PASS OVERHEAD IN THE NORTHERN CWA LATE
SATURDAY, BUT WILL NOT HAVE ANY SIGNIFICANT INFLUENCE ON MAX
TEMPS. HIGHS ON SATURDAY WILL BE IN THE MID 70S IN THE OUR NORTH
AND RANGE TO THE UPPER 70S IN OUR SOUTHWESTERN CWA. A LARGE UPPER
LEVEL HIGH PRESSURE SYSTEM WILL BEGIN TO BUILD OVER THE 4-CORNERS
AREA SUNDAY, AND THIS WILL ALLOW A SURFACE WARM FRONT TO PUSH
THROUGH WESTERN KANSAS SUNDAY INTO TUESDAY. MIN TEMPS SUNDAY
SHOULD BE IN THE MID 40S TO LOWER 50S, FOLLOWED BY HIGHS ON SUNDAY
IN THE UPPER 70S TO LOWER 80S. THEN ON MONDAY WE WILL BE WITHIN
THE WARM SECTOR OF THE WARM FRONT, ALLOWING SUNNY SKIES AND SOUTH
WINDS TO EVOLVE BY THE AFTERNOON. ONE OR BOTH MONDAY OR TUESDAY
AFTERNOON`S COULD BECOME BREEZY. MAX TEMPS MONDAY WILL TOP OUT IN
THE MID 70S TO NEAR 80 DEGREES. LOWS FOR BOTH TUESDAY AND
WEDNESDAY MORNINGS WILL BE IN THE MID TO UPPER 50S, AND WILL BE
VERY SIMILAR FOR THURSDAY AND FRIDAY. MAXIMUM TEMPERATURES FOR THE
TUESDAY THROUGH THURSDAY PERIOD WILL BE WARM, GENERALLY IN THE MID
TO UPPER 80S. A SOUTHERLY LOW LEVEL FLOW WILL EXIST TUESDAY
THROUGH THURSDAY, WITH MODEL PROGGED TEMPS IN THE 16C TO 24C RANGE
DURING THE AFTERNOONS.
BASICALLY, I SIMPLY LOADED THE CREXTENDFCST_INIT PROCEDURE AND WENT
WITH THOSE GRIDS. THERE WAS A SMALL BULLSEYE OF 20 PERCENT POPS
IN OUR SOUTHEASTERN CWA FOR THURSDAY, BUT I REDUCED THOSE POPS TO
LESS THAN 15 PERCENT AS THE MODELS DID NOT SUPPORT ANY RAIN THEN.
THUS, THE FORECAST WILL BE DRY SATURDAY THROUGH THURSDAY. STRONG
HIGH PRESSURE ANCHORED TO OUR WEST WILL DOMINATE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1242 AM CDT FRI APR 20 2012
WHAT APPEARS TO BE A SLOWLY EXPANDING AREA OF MVFR STRATUS IS MOVING
SOUTHWESTWARD FROM NORTH CENTRAL KANSAS AT THIS TIME. THE SURFACE
OBSERVATIONS INDICATE THE REGION REMAINS IN A WEAK NORTHEAST SURFACE
FLOW. THE RUC CEILING CLOUD FORECAST ARE INDICATING THIS AREA WOULD
EXPAND ACROSS THE LARGER PORTION OF WEST CENTRAL KANSAS BY AROUND 8
OR 9 UTC AS THE SURFACE HIGH PRESSURE RIDGE BUILDS OVER THE AREA.
THIS SOLUTION SEEMS REASONABLE GIVEN THE UPPER THICK CLOUD COVER
APPEARS SCATTERED AT BEST AND ADDITIONAL COOLING IS LIKELY. WE HAVE
RELATIVELY LOW CONFIDENCE IN HOW THE STRATUS FIELD WILL EVOLVE
OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 39 76 49 / 20 0 0 0
GCK 67 40 77 47 / 10 0 0 0
EHA 68 41 79 50 / 10 0 0 0
LBL 68 40 78 51 / 10 0 0 0
HYS 64 38 76 47 / 10 0 0 0
P28 66 41 75 49 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RUSSELL
SHORT TERM...BURGERT
LONG TERM...BURKE
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1244 AM CDT FRI APR 20 2012
...UPDATED FOR AVIATION...
.SYNOPSIS...
ISSUED AT 1219 PM CDT THU APR 19 2012
UPPER AIR ANALYSIS AT 12Z THURSDAY INDICATED AN UPPER LEVEL JET
EXTENDED FROM WASHINGTON STATE SOUTHEAST INTO NORTHEASTERN
NEVADA. NEAR THE LEFT EXIT REGION OF THIS JET A -26 TO -28C 500MB
THERMAL TROUGH WAS LOCATED OVER MONTANA. 40 TO 50 METER HEIGHT
FALLS WERE ALSO OBSERVED AT RAPID CITY SOUTH DAKOTA AND DENVER
COLORADO WHILE ACROSS ALONG THE PACIFIC NORTHWEST 50 TO 70 METER
HEIGHT RISES WERE OCCURRING. IN THE CENTRAL PLAINS AT 12Z THURSDAY
BOTH THE 850MB AND 700MB LEVELS INDICATED AN AREA OF MOISTURE WAS
LOCATED NEAR A 850-700MB BAROCLINIC ZONE THAT EXTENDED FROM
NORTHEAST COLORADO INTO CENTRAL NEBRASKA. AT 13Z A SURFACE A COLD
FRONT EXTENDED FROM JUST WEST OF HAYS SOUTH ACROSS THE DODGE CITY
AREA INTO THE PANHANDLE OF TEXAS AND OKLAHOMA.
&&
.UPDATE...
ISSUED AT 1134 PM CDT THU APR 19 2012
INFRARED SATELLITE IMAGERY AS WELL A REGIONAL RADAR AND METAR
OBSERVATIONS SHOW A PICTURE THIS EVENING OF SHOWERS BEING ABLE TO
MAKE PRECIPITATION REACH THE GROUND ACROSS WESTERN NEBRASKA AND
NORTHEAST COLORADO. THAT REGION WILL BE BEST CENTERED IN THE LEFT
FRONT QUADRANT OF THE UPPER LEVEL JET AS IT DIVES SOUTH OVERNIGHT.
A PERUSAL OF THE MODELS, INCLUDING THE LATEST ARW-WRF/NMM-WRF FOCUS
PRECIPITATION CHANCES WITH A COMPACT AREA OF LIFT PROBABLY
ASSOCIATED WITH THE THERMALLY INDIRECT TRANSVERSE CIRCULATION THAT
REMAINS BETTER TIED TO NORTHWEST KANSAS. ADDITIONALLY THE LAST FEW
HOURS, IT APPEAR THAT THE NAM AND OTHER MODELS HAVE SIGNIFICANTLY
OVER FORECAST THE QPF SO FAR THIS EVENING, PERHAPS OWING TO THE
NOTICEABLE DRY LAYER BETWEEN 800 AND 600 MB ON THE 00 UTC KDDC
SOUNDING. AS A RESULT, WE`LL CONTINUE THE THE DOWNTREND ON
PROBABILITIES FOR MEASURABLE PRECIPITATION OVERNIGHT WITH LESS THAN 20
PERCENT AREAL COVERAGE FOR SHOWERS, AS WEAK HIGH PRESSURE
CONTINUES TO SETTLE ACROSS THE AREA OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 152 PM CDT THU APR 19 2012
12Z NAM AND GFS REMAINS FAIRLY CONSISTENT WITH PREVIOUS RUNS IN
DEVELOPING CONVECTION LATE THIS AFTERNOON OVER THE HIGHER TERRAIN
OF COLORADO AS AN UPPER LEVEL JET APPROACHES THE ROCKIES. ANOTHER
AREA OF LATE DAY CONVECTION WILL ALSO BE POSSIBLE NEAR A COLD
FRONT WHICH WAS CROSSING SOUTH CENTRAL KANSAS AS OF 18Z. AT THIS
TIME IT APPEARS BASED ON THE HRRR AND NAM THIS FRONT WILL BE EAST
OF THE PRATT AND MEDICINE LODGE AREAS BY 00Z SO ANY PRECIPITATION
THAT WILL DEVELOP ALONG THIS BOUNDARY IS GOING TO OCCUR EAST OF
THESE LOCATIONS. FURTHER WEST BEHIND THIS FRONT THERE WILL STILL BE
SOME WEAK MID LEVEL INSTABILITY BASED ON MODEL SOUNDINGS EARLY
TONIGHT AND THE NAM EVEN GENERATES SOME VERY LIGHT QPF IN THIS AREA
OF INSTABILITY. AT THIS TIME GIVEN THE DRY AIR FORECAST BELOW THE
800MB LEVEL AM THINKING ONLY CLOUDS AND POSSIBLY VIRGA BUT WILL
CONTINUE TO MONITOR THIS AND ADJUST AS NEEDED FOR THE FIRST FEW
HOURS OF THE EVENING PERIOD.
CONVECTION DEVELOPING FURTHER WEST NEAR THE LEFT EXIT REGION OF
AN UPPER LEVEL JET APPEAR TO STAY WEST OF THE COLORADO BORDER
THROUGH 00Z. THESE STORMS ARE THEN FORECAST TO SPREAD EAST INTO
WESTERN KANSAS OVERNIGHT AS A 500MB THERMAL THROUGH WHICH WAS
LOCATED IN MONTANA AT 12Z THURSDAY MOVES SOUTHEAST INTO WESTERN
KANSAS. TRACK OF THIS UPPER TROUGH SUGGESTS PRECIPITATION CHANCES
WILL CONTINUE THROUGH EARLY FRIDAY AFTERNOON...ESPECIALLY EAST OF
HIGHWAY 283. THE PREVIOUS FORECAST HAS A DECENT HANDLE ON THE
EVOLUTION OF THIS PRECIPITATION SPREADING EAST ACROSS WESTERN
KANSAS LATER TONIGHT AND EARLY FRIDAY SO WILL STAY CLOSE TO THE
PREVIOUS TREND. DID HOWEVER POSTPONE THE ONSET OF THE
PRECIPITATION ACROSS THE FAR WEST UNTIL AFTER 00Z.
AS THE PRECIPITATION ENDS FROM WEST TO EAST THE SKIES ARE
EXPECTED TO CLEAR AS SUBSIDENCE DEVELOPS BEHIND THE UPPER LEVEL
TROUGH. BASED ON THE 18Z FRIDAY AND 00Z SATURDAY 925-950M
TEMPERATURES AND CLEARING SKIES WILL CONTINUE TO FAVOR HIGHS IN
THE MID 60S ACROSS MUCH OF WESTERN KANSAS. FURTHER EAST UPPER 50S
TO LOWER 60S APPEAR MORE REASONABLE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 245 PM CDT THU APR 19 2012
"WARM AND DRY" CAN DESCRIBE MOST OF THE EXTENDED PERIOD. WE WILL
SEE MODERATING TEMPERATURES OVER THE WEEKEND AS SURFACE LEE
TROUGHING STRENGTHENS. THE MAIN HEAT STORY BEGINS TUESDAY AND
CONTINUES THROUGH THE REST OF THE EXTENDED PERIOD AS 500 HPA
GEOPOTENTIAL HEIGHTS INCREASE IN RESPONSE TO AN AMPLIFIED RIDGE
BUILDING OVER THE ROCKIES. 850 HPA TEMPERATURES START AROUND 26-28
DEG C TUESDAY AND PEAK AROUND 28-30 DEG C BY THE END OF NEXT WEEK.
THIS SUPPORTS MIX DOWN TEMPERATURES WELL INTO THE 80S DEG F AND
MOST LIKELY SOME LOCATIONS WILL SEE >90 DEG F TEMPS. OVERNIGHT LOWS
THROUGH THE EXTENDED PERIOD WILL BE MILD AS MODERATE DEWPOINTS AND
SOUTHERLY WINDS CONTINUE. WILL KEEP SILENT POPS IN AS ANY UPPER LEVEL
FORCING REMAINS TO BE UNSEEN AND WEAK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1242 AM CDT FRI APR 20 2012
WHAT APPEARS TO BE A SLOWLY EXPANDING AREA OF MVFR STRATUS IS MOVING
SOUTHWESTWARD FROM NORTH CENTRAL KANSAS AT THIS TIME. THE SURFACE
OBSERVATIONS INDICATE THE REGION REMAINS IN A WEAK NORTHEAST SURFACE
FLOW. THE RUC CEILING CLOUD FORECAST ARE INDICATING THIS AREA WOULD
EXPAND ACROSS THE LARGER PORTION OF WEST CENTRAL KANSAS BY AROUND 8
OR 9 UTC AS THE SURFACE HIGH PRESSURE RIDGE BUILDS OVER THE AREA.
THIS SOLUTION SEEMS REASONABLE GIVEN THE UPPER THICK CLOUD COVER
APPEARS SCATTERED AT BEST AND ADDITIONAL COOLING IS LIKELY. WE HAVE
RELATIVELY LOW CONFIDENCE IN HOW THE STRATUS FIELD WILL EVOLVE
OVERNIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 39 76 49 80 / 0 0 0 0
GCK 40 77 47 81 / 0 0 0 0
EHA 41 79 50 82 / 0 0 0 0
LBL 40 78 51 82 / 0 0 0 0
HYS 38 76 47 77 / 0 0 0 0
P28 41 75 49 79 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RUSSELL
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...RUSSELL
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1137 PM CDT THU APR 19 2012
...UPDATED FOR PRECIPITATION TRENDS...
.SYNOPSIS...
ISSUED AT 1219 PM CDT THU APR 19 2012
UPPER AIR ANALYSIS AT 12Z THURSDAY INDICATED AN UPPER LEVEL JET
EXTENDED FROM WASHINGTON STATE SOUTHEAST INTO NORTHEASTERN
NEVADA. NEAR THE LEFT EXIT REGION OF THIS JET A -26 TO -28C 500MB
THERMAL TROUGH WAS LOCATED OVER MONTANA. 40 TO 50 METER HEIGHT
FALLS WERE ALSO OBSERVED AT RAPID CITY SOUTH DAKOTA AND DENVER
COLORADO WHILE ACROSS ALONG THE PACIFIC NORTHWEST 50 TO 70 METER
HEIGHT RISES WERE OCCURRING. IN THE CENTRAL PLAINS AT 12Z THURSDAY
BOTH THE 850MB AND 700MB LEVELS INDICATED AN AREA OF MOISTURE WAS
LOCATED NEAR A 850-700MB BAROCLINIC ZONE THAT EXTENDED FROM
NORTHEAST COLORADO INTO CENTRAL NEBRASKA. AT 13Z A SURFACE A COLD
FRONT EXTENDED FROM JUST WEST OF HAYS SOUTH ACROSS THE DODGE CITY
AREA INTO THE PANHANDLE OF TEXAS AND OKLAHOMA.
&&
.UPDATE...
ISSUED AT 1134 PM CDT THU APR 19 2012
INFRARED SATELLITE IMAGERY AS WELL A REGIONAL RADAR AND METAR
OBSERVATIONS SHOW A PICTURE THIS EVENING OF SHOWERS BEING ABLE TO
MAKE PRECIPITATION REACH THE GROUND ACROSS WESTERN NEBRASKA AND
NORTHEAST COLORADO. THAT REGION WILL BE BEST CENTERED IN THE LEFT
FRONT QUADRANT OF THE UPPER LEVEL JET AS IT DIVES SOUTH OVERNIGHT.
A PERUSAL OF THE MODELS, INCLUDING THE LATEST ARW-WRF/NMM-WRF FOCUS
PRECIPITATION CHANCES WITH A COMPACT AREA OF LIFT PROBABLY
ASSOCIATED WITH THE THERMALLY INDIRECT TRANSVERSE CIRCULATION THAT
REMAINS BETTER TIED TO NORTHWEST KANSAS. ADDITIONALLY THE LAST FEW
HOURS, IT APPEAR THAT THE NAM AND OTHER MODELS HAVE SIGNIFICANTLY
OVER FORECAST THE QPF SO FAR THIS EVENING, PERHAPS OWING TO THE
NOTICEABLE DRY LAYER BETWEEN 800 AND 600 MB ON THE 00 UTC KDDC
SOUNDING. AS A RESULT, WE`LL CONTINUE THE THE DOWNTREND ON
PROBABILITIES FOR MEASURABLE PRECIPITATION OVERNIGHT WITH LESS THAN 20
PERCENT AREAL COVERAGE FOR SHOWERS, AS WEAK HIGH PRESSURE
CONTINUES TO SETTLE ACROSS THE AREA OVERNIGHT.
&&
.SHORT TERM...(THIS EVENING THROUGH TOMORROW)
ISSUED AT 152 PM CDT THU APR 19 2012
12Z NAM AND GFS REMAINS FAIRLY CONSISTENT WITH PREVIOUS RUNS IN
DEVELOPING CONVECTION LATE THIS AFTERNOON OVER THE HIGHER TERRAIN
OF COLORADO AS AN UPPER LEVEL JET APPROACHES THE ROCKIES. ANOTHER
AREA OF LATE DAY CONVECTION WILL ALSO BE POSSIBLE NEAR A COLD
FRONT WHICH WAS CROSSING SOUTH CENTRAL KANSAS AS OF 18Z. AT THIS
TIME IT APPEARS BASED ON THE HRRR AND NAM THIS FRONT WILL BE EAST
OF THE PRATT AND MEDICINE LODGE AREAS BY 00Z SO ANY PRECIPITATION
THAT WILL DEVELOP ALONG THIS BOUNDARY IS GOING TO OCCUR EAST OF
THESE LOCATIONS. FURTHER WEST BEHIND THIS FRONT THERE WILL STILL BE
SOME WEAK MID LEVEL INSTABILITY BASED ON MODEL SOUNDINGS EARLY
TONIGHT AND THE NAM EVEN GENERATES SOME VERY LIGHT QPF IN THIS AREA
OF INSTABILITY. AT THIS TIME GIVEN THE DRY AIR FORECAST BELOW THE
800MB LEVEL AM THINKING ONLY CLOUDS AND POSSIBLY VIRGA BUT WILL
CONTINUE TO MONITOR THIS AND ADJUST AS NEEDED FOR THE FIRST FEW
HOURS OF THE EVENING PERIOD.
CONVECTION DEVELOPING FURTHER WEST NEAR THE LEFT EXIT REGION OF
AN UPPER LEVEL JET APPEAR TO STAY WEST OF THE COLORADO BORDER
THROUGH 00Z. THESE STORMS ARE THEN FORECAST TO SPREAD EAST INTO
WESTERN KANSAS OVERNIGHT AS A 500MB THERMAL THROUGH WHICH WAS
LOCATED IN MONTANA AT 12Z THURSDAY MOVES SOUTHEAST INTO WESTERN
KANSAS. TRACK OF THIS UPPER TROUGH SUGGESTS PRECIPITATION CHANCES
WILL CONTINUE THROUGH EARLY FRIDAY AFTERNOON...ESPECIALLY EAST OF
HIGHWAY 283. THE PREVIOUS FORECAST HAS A DECENT HANDLE ON THE
EVOLUTION OF THIS PRECIPITATION SPREADING EAST ACROSS WESTERN
KANSAS LATER TONIGHT AND EARLY FRIDAY SO WILL STAY CLOSE TO THE
PREVIOUS TREND. DID HOWEVER POSTPONE THE ONSET OF THE
PRECIPITATION ACROSS THE FAR WEST UNTIL AFTER 00Z.
AS THE PRECIPITATION ENDS FROM WEST TO EAST THE SKIES ARE
EXPECTED TO CLEAR AS SUBSIDENCE DEVELOPS BEHIND THE UPPER LEVEL
TROUGH. BASED ON THE 18Z FRIDAY AND 00Z SATURDAY 925-950M
TEMPERATURES AND CLEARING SKIES WILL CONTINUE TO FAVOR HIGHS IN
THE MID 60S ACROSS MUCH OF WESTERN KANSAS. FURTHER EAST UPPER 50S
TO LOWER 60S APPEAR MORE REASONABLE.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 245 PM CDT THU APR 19 2012
"WARM AND DRY" CAN DESCRIBE MOST OF THE EXTENDED PERIOD. WE WILL
SEE MODERATING TEMPERATURES OVER THE WEEKEND AS SURFACE LEE
TROUGHING STRENGTHENS. THE MAIN HEAT STORY BEGINS TUESDAY AND
CONTINUES THROUGH THE REST OF THE EXTENDED PERIOD AS 500 HPA
GEOPOTENTIAL HEIGHTS INCREASE IN RESPONSE TO AN AMPLIFIED RIDGE
BUILDING OVER THE ROCKIES. 850 HPA TEMPERATURES START AROUND 26-28
DEG C TUESDAY AND PEAK AROUND 28-30 DEG C BY THE END OF NEXT WEEK.
THIS SUPPORTS MIX DOWN TEMPERATURES WELL INTO THE 80S DEG F AND
MOST LIKELY SOME LOCATIONS WILL SEE >90 DEG F TEMPS. OVERNIGHT LOWS
THROUGH THE EXTENDED PERIOD WILL BE MILD AS MODERATE DEWPOINTS AND
SOUTHERLY WINDS CONTINUE. WILL KEEP SILENT POPS IN AS ANY UPPER LEVEL
FORCING REMAINS TO BE UNSEEN AND WEAK.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 620 PM CDT THU APR 19 2012
MOSTLY CLOUDY SKIES ARE ANTICIPATED OVERNIGHT AS MID LEVEL
MOISTURE POOLS BEHIND A COLD FRONT DRAPED ACROSS OKLAHOMA AND THE
TEXAS PANHANDLE. MOSTLY CLOUDY SKIES AOA045 ARE FORECASTED BY
MIDNIGHT WITH A CHANCE OF LIGHT RAIN SHOWERS BEFORE SUNRISE
TOMORROW. WINDS WILL GENERALLY BE FROM THE NORTH AROUND 12 KNOTS
GUSTING TO OVER 15 KNOTS AT TIME.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 44 61 39 76 / 20 20 0 0
GCK 43 62 40 77 / 20 10 0 0
EHA 45 66 41 79 / 30 10 0 0
LBL 45 65 40 78 / 30 10 0 0
HYS 41 60 38 76 / 20 10 0 0
P28 46 62 41 75 / 10 10 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RUSSELL
SHORT TERM...BURGERT
LONG TERM...SUGDEN
AVIATION...HOVORKA 42
AREA FORECAST DISCUSSION
NWS GAYLORD MI
201 AM EDT FRI APR 20 2012
.SYNOPSIS...
ISSUED AT 433 PM EDT THU APR 19 2012
A STORM SYSTEM ORGANIZING OVER THE PLAINS...WILL LIFT TOWARD THE
OHIO VALLEY TONIGHT...BEFORE EXITING EAST INTO LAKE ONTARIO FRIDAY.
RAIN WILL OVERSPREAD THE STATE THIS EVENING...IN ADVANCE OF THE
APPROACHING SYSTEM. THE RAIN WILL CHANGE TO SNOW ACROSS EAST UPPER
AND THE STRAITS REGION OVERNIGHT...AS COLDER AIR FILTERS INTO THE
NORTHERN GREAT LAKES. COLD AIR WILL CONTINUE TO PUSH ACROSS THE STATE
FRIDAY...GENERATING SNOW FOR MUCH OF NORTHERN MICHIGAN.
HIGH PRESSURE FROM THE UPPER MIDWEST AND CENTRAL CANADA...WILL BUILD
INTO THE GREAT LAKES FRIDAY NIGHT...ON THE BACKSIDE OF THE EXITING
OHIO VALLEY SYSTEM. HIGH PRESSURE WILL THEN LINGER OVER THE STATE
INTO THE BEGINNING OF THE UPCOMING WORK WEEK. THIS PATTERN WILL
GENERATE SOME SUN AND MILD TEMPERATURES THROUGH THE WEEKEND.
&&
.UPDATE...
ISSUED AT 140 AM EDT FRI APR 20 2012
ONGOING PRECIPITATION IS BEHAVING AS PLANNED...WITH STEADY AND
HEAVIEST RAINFALL OCCURRING WITHIN LOW TO MID LEVEL FGEN AND MAX
DEEP LAYER -DIVQ...FROM NRN LEELANAU COUNTY THROUGH CHARLEVOIX
AND NRN LAKE HURON. H8 WINDS ARE VEERING IN RESPONSE TO
APPROACHING LOW PRESSURE...THUS WAA IS CONTINUING ACROSS NRN LOWER
AND KEEPING ANY LIQUID FROM CHANGING TO SNOW. THE DOWNWARD BRANCH
OF THE FGEN CIRCULATION IS OBVIOUSLY AFFECTING EASTERN UPPER
MICHIGAN. CEILINGS WERE STILL ONLY 6KFT AT KINROSS AND 10KFT AT
SSM. MOST OF THE HEAVIER RAINFALL WILL CONTINUE THROUGH ROUGHLY
11Z-12Z WHEN THE STRONG FGEN SIGNAL WILL LIFT EAST OF US AND THE
LLJ BEGINS TO WEAKEN. THE SUBSEQUENTLY WEAKENED DOWNWARD BRANCH OF
THE FGEN CIRCULATION WILL LOOSEN IT`S GRIP ON EASTERN UPPER...AND
LIGHT PRECIPITATION WILL START TO FALL. THIS SHOULD BE MIXED WITH
SNOW...EARLY ON...BUT AS COLDER AIR THEN FILTERS IN BEHIND THE
DEPARTING H8 LOW...A CHANGEOVER TO SNOW WILL OCCUR FROM NW TO SE
THROUGH THE MORNING. SNOW AMOUNTS MAY NEED TO BE LOWERED A TOUCH
MORE...BUT THIS WILL HAVE TO BE BASED HEAVILY ON CHANGEOVER TIMES
BY WATCHING OBS/DUAL POL RADAR IMAGERY.
PRECIPITATION IS EXPECTED TO MAKE A SLIGHTLY QUICKER EXIT WITH
ONLY SOME CHANCE/SLIGHT CHANCE STUFF FOR THE GREATER PART OF THE
AFTERNOON.
UPDATE ISSUED AT 1023 PM EDT THU APR 19 2012
WILL GO AHEAD AND ADD EMMET...CHEBOYGAN...PRESQUE ISLE COUNTIES TO
THE ADVISORY WITH THIS ISSUANCE BASED ON RECENT OBSERVATIONAL
TRENDS...AS WELL AS NEW 00Z NAM...AS WELL AS OUR IN HOUSE LOCAL
WRF AND HRRR. DUAL POL DATA CONFIRMS THAT THE MELTING LAYER IS AT
ABOUT 3-4KFT AT APX...AND HAS DIPPED DOWN BELOW 2KFT AT TIMES.
OBSERVATIONS FROM ACROSS LAKE MICHIGAN ARE SHOWING RAIN CHANGING
TO SNOW AT WAUSAU...WITH TEMPERATURES FALLING QUICKLY UNDER
DEVELOPING BANDED PRECIPITATION IN FGEN/DEFORMATION BULLSEYE IN
THE H85-H7 LEVEL.
HRRR/LOCAL WRF ARE VERY AGGRESSIVE SHOWIGN COOLING OVER THE TIP OF
THE MITT AFTER 9Z...WITH SNOW REACHING AS FAR SOUTH AS GAYLORD BY
DAYBREAK IN THESE SOLUTIONS. NEW 00Z NAM TRENDED HEAVILY IN THIS
DIRECTION...AND WHILE I THINK THE COOLING RATES ARE A LITTLE
OVERDONE...I WILL TREND THE FORECAST SLIGHTLY COOLER...AND A
LITTLE SNOWIER BEFORE DAYBREAK. GIVEN THAT CONFIDENCE IS NOW
INCREASING THAT A CHANGEOVER TO SNOW WILL OCCUR TOWARDS DAYBREAK
/WITH AMPLE PRECIPITATION LIKELY AFTER THIS POINT/ FEEL THAT THE
EXPANDED ADVISORY IS WARRANTED.
HAVE ALSO BROUGHT A DECREASE IN POPS /TO SCT SHRAS/ TO SOUTHERN
AREAS FOR A TIME TONIGHT AS BACK EDGE TO INITIAL WARM ADVECTION
SURGE PUSHES EAST...WITH A BREAK BEFORE THE FGEN-BAND SAGS SOUTH
AND EAST WELL AFTER MIDNIGHT.
UPDATE ISSUED AT 652 PM EDT THU APR 19 2012
PRIMARY UPDATE AT THIS TIME IS TO REFINE LEADING EDGE OF PRECIP
FIELD THAT IS NOW ADVANCING NORTHEAST INTO THE CWA. SURFACE LOW
NOW OVER SOUTHEASTERN IOWA WITH IMPRESSIVE WARM ADVECTION PLUME AS
BAND OF ONE INCH PWATS SURGE NORTH OVER TIGHTENING FRONTAL BOUNDARY.
OTHER FIELDS NEED VERY LITTLE IN THE WAY OF UPDATING.
DUAL POL PRODUCTS SUGGESTING A MELTING LEVEL AROUND 4KFT AGL
ATTM...SOMEWHAT BELOW NEAR TERM GUIDANCE. STILL SAFELY STARING AS
RAIN...BUT WILL BE WATCHING THESE TRENDS /AND UPCOMING 00Z APX
RAOB/ FOR MORE CLUES TO THE LLEVEL THERMAL FIELDS AS LLEVEL
AGEOSTROPHIC NORTHERLIES SLOWLY COOL THE BOUNDARY LAYER.
AM A LITTLE CONCERNED GIVEN PLACEMENT OF RUC H85-H7 FGEN SIGNATURE
/WHICH RIGHT NOW IS LINING UP BETTER WITH PRECIP PLACEMENT THAN FN
CONVERGENCE/ ALONG WITH RECENT HRRR TRENDS THAT SUGGEST THAT THE
SOUTHERN EDGE OF THE PRECIPITATION SHIELD MAY ADVANCE A BIT
FURTHER NORTH THAN CURRENTLY INDICATED...ESPECIALLY AFTER
MIDNIGHT. WILL NOT MAKE CHANGES TO THIS PORTION OF THE FORECAST
JUST YET...BUT THIS WOULD MEAN SOME REDUCED RAINFALL TOTALS SE OF
A CAD-APN LINE IF THE TRENDS HOLD.
&&
.SHORT TERM...(THIS EVENING THROUGH FRIDAY) ISSUED AT 433 PM EDT
THU APR 19 2012
EARLY AFTERNOON SURFACE ANALYSIS SHOWS 1005MB SURFACE WAVE OVER
NORTHEAST KANSAS...WARM/STATIONARY FRONT EXTENDS EAST ACROSS THE
SOUTHERN HALF OF IOWA/FAR NORTHERN ILLINOIS AND UP INTO SOUTHERN
LOWER MICHIGAN. LOW LEVEL ANTICYCLONIC FLOW ACROSS NORTHERN
MICHIGAN KEEPING WINDS OUT OF THE NORTH AND KEEPING TEMPERATURES
COOLER...PERSISTENT DIURNALLY ENHANCED STRATOCUMULUS DECK ACROSS
EASTERN UPPER ALSO HELPING KEEP TEMPERATURES IN THE LOWER-MID 40S.
BAROCLINIC ZONE COMBINED WITH WELL DEFINED VORTICITY CENTER HEADED
TOWARD THE NEBRASKA/IOWA BORDER IS SPREADING RAIN SHOWERS
EAST-NORTHEAST ACROSS IOWA/SOUTHERN MINNESOTA/SOUTHERN WISCONSIN...
WITH AN AXIS OF 1+ INCH PRECIPITABLE WATER VALUES POOLED ALONG THE
FRONT.
KANSAS SURFACE LOW FORECAST TO TRACK EAST-NORTHEAST AND INTO FAR
SOUTHWEST LOWER MICHIGAN BY FRIDAY MORNING...WITH ASSOCIATED
EAST-WEST BAROCLINIC ZONE ALSO NUDGING NORTHWARD WITH A TIGHT
THERMAL GRADIENT SETTING UP ACROSS LOWER MICHIGAN. LOOKING LIKE A
GOOD SETUP FOR A MODERATE-HEAVY PRECIPITATION EVENT...AS WARM
ADVECTION NORTH OF FRONTAL ZONE COMBINES WITH STRONGLY SLOPED
FRONTOGENETIC RESPONSE AND RIGHT ENTRANCE REGION DYNAMICS FROM
DEVELOPING JET STREAK TO THE NORTH AND NORTHEAST OF LAKE SUPERIOR.
CURRENT EXPECTATION IS THAT HEAVIEST QPF WILL SET UP ACROSS FAR
NORTHWEST LOWER MICHIGAN AND THE STRAITS REGION BASED ON LOCATION OF
STRONGEST FORCING...WILL LIKELY BE A TIGHT GRADIENT TO THE NORTH
GIVEN MID LEVEL DEFORMATION AND LOWER LAYER SUBSIDENCE IN DESCENDING
BRANCH OF FRONTOGENETIC CIRCULATION. PRECIPITATION AMOUNTS IN
EXCESS OF AN INCH APPEAR POSSIBLE WITHIN A MBL-TVC-PLN AXIS (WILL
CARRY A HEAVY RAIN MENTION IN THESE AREAS). RAINFALL IS MAKING
STEADY PROGRESS ACROSS WISCONSIN...AND WILL SPREAD INTO THE FORECAST
AREA FROM THE SOUTHWEST THIS EVENING. MAIN PROBLEM IS GOING TO BE
PRECIPITATION TYPE...AS "COLDEST" AIR BUMPS UP AGAINST NORTHERN QPF
GRADIENT ACROSS EASTERN UPPER. TEMPERATURES IN THE MID 40S/DEW
POINTS IN THE MID 30S WILL ENSURE PRECIPITATION STARTS AS RAIN FROM
THE STRAITS NORTHWARD...AFTER MIDNIGHT SOME LOW LEVEL COLD ADVECTION
FROM THE NORTHEAST AND COOLING DUE TO MELTING/EVAPORATION FORECAST
TO GRADUALLY ERODE AWAY SURFACE BASED WARM LAYER. NOT EXPECTING
SURFACE TEMPERATURES TO FALL BELOW FREEZING...BUT WARM LAYER MAY
SHRINK ENOUGH TO ALLOW PRECIP TO TRANSITION TOWARD SNOW ACROSS
EASTERN UPPER AND POSSIBLY INTO THE TIP OF THE MITT COUNTIES AS
WELL. SNOW AMOUNTS OVERNIGHT WILL ALL DEPEND ON HOW QUICKLY THIS
PROCESS OCCURS (IF IT OCCURS AT ALL...WHICH IS ALSO A POSSIBILITY).
ASSUMING A LATER TRANSITION WENT WITH UP TO 2 INCHES NORTH OF THE
BRIDGE BY DAYBREAK.
SURFACE WAVE FORECAST TO HEAD EAST FROM SOUTHERN LOWER MICHIGAN AND
INTO THE LOWER GREAT LAKES DURING THE DAY FRIDAY. UPWARD FORCING
WILL STILL BE PRETTY STRONG ACROSS NORTHERN LOWER MICHIGAN TO START
THE DAY...SHIFTING EAST DURING THE MORNING WHICH WILL PULL HEAVIER
PRECIPITATION EASTWARD WITH IT. THERMAL FIELDS ACROSS EASTERN UPPER
AND FAR NORTHERN LOWER WILL STILL BE MARGINAL WITH REGARD TO PRECIP
TYPE...ESPECIALLY ALONG M-32 CORRIDOR WHERE GUIDANCE OFFERING UP
DIFFERING IDEAS. WILL PLAY WITH THE IDEA OF ALL SNOW ACROSS EASTERN
UPPER AND ALONG THE M-68 CORRIDOR...WITH A WINTRY MIX OF RAIN/
SLEET/SNOW POSSIBLE ALONG THE M-32 CORRIDOR. SEVERAL INCHES OF SNOW
POSSIBLE ACROSS THE TIP OF THE MITT AND FAR SOUTHEAST UPPER
MICHIGAN...CURRENT FORECAST WILL HAVE A BAND OF 3-5 INCHES OF SNOW
ALONG/NORTH OF M-68...HIGHLY SUBJECT TO CHANGE AND WILL BE DEPENDENT
ON HOW THERMAL PROFILE EVOLVES. SINCE IT APPEARS THAT EASTERN UPPER
MICHIGAN WILL BE MOST LIKELY TO SEE MORE PERSISTENT SNOWFALL OUT OF
THIS EVENT...WILL GO AHEAD AND ISSUE A WINTER WEATHER ADVISORY FOR
CHIPPEWA/MACKINAC COUNTIES FOR LATE TONIGHT INTO FRIDAY MORNING. IF
COLDER AIR ARRIVES EARLY ENOUGH...HEADLINES WILL NEED TO BE EXPANDED
SOUTH INTO AT LEAST THE TIP OF THE MITT COUNTIES. BUT NOT CONFIDENT
ENOUGH ON TIMING YET...AND HAVE SOME TIME TO HOLD OFF SINCE GREATEST
THREAT FOR SNOWFALL ACROSS FAR NORTHERN LOWER WILL BE FRIDAY
MORNING.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY) ISSUED AT 433 PM EDT
THU APR 19 2012
CURRENT QUASI-ZONAL FLOW PATTERN OVER THE LOWER 48 ABOUT SET TO GO
THROUGH DEEP AMPLIFICATION...COURTESY OF RAPID UPPER JET
INTENSIFICATION TODAY OVER ONTARIO...WITH SECONDARY STRONG UPPER JET
STREAK CUTTING INTO THE PACIFIC NORTHWEST. COMBO OF THESE WILL CARVE
OUT A DEEP EASTERN TROUGH THIS WEEKEND INTO EARLY NEXT WEEK...ITSELF
BOOKENDED BY AMPLIFYING INTERMOUNTAIN WEST AND DAVIS STRAITS
RIDGING. SAID CONFIGURATION PLACES NORTHERN MICHIGAN IN SOMEWHAT
PROLONGED PERIOD OF MAINLY DRY AND SEASONABLY COOL NORTH TO EAST
FLOW THOUGH EARLY NEXT WEEK. FORECAST CONCERNS CENTER ON TEMPERATURE
TRENDS AND PERIODIC LOW END RAIN CHANCES AS WEAK MOISTURE STARVED
WAVES ADVANCE THROUGH BACKSIDE OF EASTERN TROUGH.
FIRST THINGS FIRST...AND MAY STILL BE DEALING WITH A FEW RAIN/SNOW
SHOWERS EARLY FRIDAY EVENING AS LAST VESTIGES OF TONIGHTS/FRIDAY
SYSTEM (SEE SHORT TERM DISCUSSION) EXIT STAGE RIGHT. INFILTRATION OF
NORTH FLOW DEEP LAYER DRYING AND SURFACE HIGH PRESSURE SHOULD BRING
A QUICK END TO ANY PRECIP...LEAVING OVERNIGHT FRIDAY RIGHT THROUGH
SATURDAY NIGHT DRY WITH GRADUALLY DECREASING CLOUD COVER. WHILE
INCREASING AMOUNTS OF SUNSHINE SATURDAY WILL PARTIALLY OFFSET
MAINTENANCE OF COOL NORTH WINDS...CLEAR SKIES AND QUICK DECOUPLING
OFF LOW LEVEL WINDS WILL ALLOW TEMPERATURES TO DROP RAPIDLY SATURDAY
EVENING. LAST FEW WEEKS HAVE SEEN PLENTY OF SIMILAR SCENARIOS...AND
EACH HAVE RESULTED IN COLDER READINGS THAN GUIDANCE INITIALLY
ANTICIPATED. EXPECT THIS TO BE THE CASE ONCE AGAIN...AND HAVE GONE
AHEAD A CUT LOWS BY SEVERAL DEGREES...WITH MOST INLAND AREAS DOWN
INTO THE 20S BY EARLY SUNDAY MORNING (IF CURRENT TRENDS CONTINUE...
COULD EVEN SEE THE NEED TO LOWER TEMPERATURES A FEW MORE DEGREES IN
THE TYPICAL ICE BOX LOCATIONS).
SOME UNCERTAINTY FOR THE REMAINDER OF THE WEEKEND INTO THE MIDDLE
PORTIONS OF NEXT WEEK...MAINLY CENTERING ON LIGHT PRECIP POTENTIAL
SUNDAY WITH MOISTURE STARVED NORTHERN STREAM WAVE...AND WITH
ADDITIONAL RAIN CHANCES TUESDAY AND WEDNESDAY. AS FOR THE
FORMER...POSITION OF AFOREMENTIONED LARGE SCALE FEATURES SUGGEST
"BEST" DYNAMICS AND WAA FORCED ASCENT REMAINING TO OUR WEST ON
SUNDAY. DRY NORTHEAST LOW LEVEL FLOW ALSO SUGGESTS DRY WEATHER
CONTINUING THROUGH SUNDAY. MAINTENANCE OF NEAR STATIONARY SURFACE
HIGH STILL SUPPORTS A DRY BEGINNING TO NEXT WORK WEEK UNDER MOSTLY
CLEAR TO PARTLY CLOUDY SKIES. TYPICAL SPRINGTIME AIRMASS
MODIFICATION RESULTS IN SOME SLOW WARMING...WITH HIGHS MOSTLY IN THE
LOWER 50S BY MONDAY (A TOUCH COOLER NEAR THE BIG LAKES AND ACROSS
EASTERN UPPER). MUCH UNCERTAINTY REMAINS WITH THE MID WEEK RAIN
POTENTIAL...WITH LATEST (AND RATHER ROCK STEADY) ECMWF SHOWING MUCH
MORE AMPLIFIED AND SLOWER TO LEAVE EASTERN LAKES/EASTERN US TROUGH
THAN OTHER GUIDANCE. ECMWF SOLUTION WOULD EVEN SUGGEST SOME ATLANTIC
MOISTURE PINWHEELING BACK WEST...BRINGING AT LEAST THE THREAT OF
SOME RAINS TO OUR EASTERN AREAS TUESDAY AND TUESDAY NIGHT. THIS DOES
SEEM A TOUCH EXTREME...ALTHOUGH FEEL ITS DEPICTION OF A MORE
AGGRESSIVE EASTERN TROUGH IS VERY PLAUSIBLE. OTHER PROGS...
ESPECIALLY THE SOMEWHAT MORE PROGRESSIVE GFS...WOULD SUGGEST A MID
WEEK SHOWER THREAT VIA ADDITIONAL NORTHERN STREAM ENERGY DROPPING ON
BACKSIDE OF SLOWLY DEPARTING EAST CANADA TROUGH AXIS. CONFIDENCE ON
HOW THIS WILL PLAY OUT REMAINS EXCEPTIONALLY LOW...AND WILL SIMPLY
RIDE WITH A MODEL BLEND APPROACH...FEATURING LOW END RAIN CHANCES
TUESDAY NIGHT INTO WEDNESDAY. TEMPERATURES WILL ALSO BE HIGHLY
DEPENDENT ON HOW THE ABOVE UNFOLDS...WITH SOME POTENTIAL FOR COOL
NORTHERLY FLOW TO CONTINUE. WILL SHOW A SLOW WARMING TREND...BUT
WOULD NOT BE SURPRISED IF THIS...AND RAIN POTENTIAL...SEES
SIGNIFICANT CHANGES IN THE COMING DAYS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 140 AM EDT FRI APR 20 2012
APPROACHING LOW PRESSURE WILL CONTINUE TO PRODUCE NEAR STEADY
RAINFALL WITH MVFR VSBYS THROUGH THE MORNING...WITH IFC CIGS
THROUGH A GOOD CHUNK OF THE DAY. GUSTIER NE WINDS DEVELOP THROUGH
THE DAY AS THE LOW PRESSURE BEGINS TO DEPART THROUGH THE THUMB OF
LOWER MICHIGAN. VFR CONDITIONS DEVELOP BY THIS EVENING WITH MUCH
DRIER AIR ARRIVING AHEAD OF HIGH PRESSURE POKING INTO THE NW GREAT
LAKES.
&&
.MARINE...
ISSUED AT 433 PM EDT THU APR 19 2012
INCREASINGLY GUSTY NORTHEAST WINDS NORTH OF PASSING SOUTHERN LAKES
LOW PRESSURE WILL RESULT IN SCA/S ACROSS MOST NEARSHORE WATERS
BORDERING NORTHERN LOWER MICHIGAN TONIGHT INTO FRIDAY AFTERNOON.
STRONGEST WINDS EXPECTED OVER NORTHERN LAKE HURON LATE TONIGHT INTO
FRIDAY...WITH GALE FORCE WIND GUSTS EXPECTED FROM NEAR THE STRAITS
DOWN TO STURGEON POINT. CONDITIONS WILL IMPROVE FRIDAY NIGHT INTO
THE WEEKEND AS HIGH PRESSURE BUILDS OVERHEAD.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY UNTIL NOON EDT TODAY FOR MIZ008-015>018.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LHZ345-
346-349.
GALE WARNING FROM 5 AM EARLY THIS MORNING TO 5 PM EDT THIS
AFTERNOON FOR LHZ347-348.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EDT THIS AFTERNOON FOR LMZ323-
341-342-344>346.
LS...NONE.
&&
$$
UPDATE...SD
SYNOPSIS...SR
SHORT TERM...JB
LONG TERM...MB
AVIATION...SD
MARINE...MB
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1129 PM CDT THU APR 19 2012
.UPDATE...
06Z AVIATION DISCUSSION ADDED BELOW.
&&
.DISCUSSION...
PRIMARY WEATHER FEATURES OF CONCERN ARE THE SHORTWAVE AND
ASSOCIATED SURFACE LOW CURRENTLY MOVING BY TO OUR SOUTH... AND
ANOTHER SHORTWAVE WHICH WILL BE EMBEDDED IN NORTHWEST UPPER FLOW
THAT WILL MOVE THROUGH THE REGION ON SATURDAY. OVERALL... THE
LARGE SCALE PATTERN WILL EVOLVE FROM ITS FAIRLY ZONAL FLOW AT THE
MOMENT TO A MUCH MORE AMPLIFIED PATTERN AS WE WORK THROUGH THE
UPCOMING WEEK. THE NUMERICAL GUIDANCE IS IN GOOD AGREEMENT ON THE
INITIAL AMPLIFICATION OF THE UPPER FLOW... BUT DIVERGES QUITE A
BIT IN HOW THINGS WILL THEN EVOLVE DURING THE MIDDLE PART OF NEXT
WEEK. GENERALLY FOLLOWED A NAM/GFS BLEND THROUGH THE NEXT FEW
DAYS... THEN STEADILY WORKED WITH MORE OF AN ECMWF/GFS BLEND
BEYOND THAT WITH A BIT MORE WEIGHT ON THE ECMWF BY THE MIDDLE OF
NEXT WEEK. OVERALL... CONFIDENCE IS FAIRLY LOW IN THE DETAILS OF
THE TUESDAY THROUGH THURSDAY TIME PERIOD NEXT WEEK... SINCE MUCH
WILL DEPEND ON IF/WHEN THE RIDGE WILL BREAK DOWN. THE ECMWF
MAINTAINS THE RIDGE MUCH MORE THAN THE GFS... WHICH PUSHES AN
UPPER LOW SOUTH TOWARD THE REGION FROM CENTRAL CANADA.
SURFACE LOW CURRENTLY OVER FAR NORTHEAST KANSAS WILL CONTINUE TO
PUSH EAST-NORTHEAST THIS EVENING AS THE UPPER SHORTWAVE WORKS INTO
THE MID-MISSISSIPPI VALLEY. THE BEST ISENTROPIC LIFT AND MID-LEVEL
FRONTOGENESIS WILL BE ACROSS THE SOUTHERN PART OF OUR CWFA AND
INTO NORTHERN IOWA AND SOUTHWEST WISCONSIN. DECENT PCPN TOTALS CAN
BE EXPECTED SOUTH OF A LINE FROM MANKATO TO EAU CLAIRE AS THE
SYSTEM PUSHES THROUGH THIS AFTERNOON AND EVENING. THE BACK EDGE OF
THE PCPN MAY MIX WITH AND/OR CHANGE TO SOME SNOW THIS EVENING AS
COLDER AIR WORKS IN BEHIND THE UPPER WAVE. FORECAST SOUNDINGS FROM
THE NAM... GFS... AND RUC SUGGEST ONLY A BRIEF WINDOW OF SNOW
POTENTIAL ACROSS OUR AREA... MAINLY OVER PARTS OF WEST CENTRAL
WISCONSIN. BETTER ACCUMULATION POTENTIAL EXISTS EAST AND SOUTHEAST
OF OUR AREA... WHERE THERE LOOKS TO BE A LONGER DURATION OF A SUB-
FREEZING PROFILE... DEEP MOISTURE... AND LIFT. A WEAK RIDGE OF
HIGH PRESSURE WILL WORK ACROSS THE REGION LATE TONIGHT THROUGH
FRIDAY... WITH DRY WEATHER EXPECTED. THE RIDGE WILL STILL BE IN
PLACE ACROSS THE EASTERN FORECAST AREA FRIDAY NIGHT... WHICH COULD
LEAD TO SOME FROST/FREEZE ISSUES. INCLUDED A MENTION OF PATCHY
FROST IN THOSE AREAS FOR NOW TO ACCOUNT FOR THAT POSSIBILITY.
RETURN FLOW AND WARM ADVECTION WILL START TO ENCROACH ON THE
WESTERN PORTION OF THE AREA FRIDAY NIGHT... SO INCLUDED A CHANCE
OF SHRA OUT THERE FOR THE OVERNIGHT HOURS. THAT CHANCE FOR PCPN
THEN MIGRATES EASTWARD ACROSS THE AREA ON SATURDAY AS THE ZONE OF
ISENTROPIC LIFT WORKS ACROSS THE CWFA WITH AN EMBEDDED SHORTWAVE
IN NORTHWEST FLOW DROPPING THROUGH AT THE SAME TIME. THE MOST
PERSISTENT AND SUBSTANTIAL PCPN LOOKS LIKE IT SHOULD FOCUS MAINLY
TO OUR NORTH... BUT WOULD EXPECT MOST LOCATIONS TO SEE AT LEAST A
BRIEF WINDOW OF SOME PCPN ON SATURDAY INTO SATURDAY NIGHT. PCPN
CHANCES MAY LINGER ACROSS THE EAST ON SUNDAY ON THE BACKSIDE OF
THE UPPER TROUGH BEFORE MORE PRONOUNCED UPPER AND SURFACE RIDGING
ARE ABLE TO WORK INTO THE AREA.
FOR THE MONDAY THROUGH THURSDAY PERIOD... CONFIDENCE IS QUITE LOW
IN THE FORECAST DETAILS AS ELUDED TO EARLIER. TRIED TO SIDE A BIT
MORE WITH THE ECMWF... ALTHOUGH IT SHOULD BE NOTED THAT ITS 12Z
SOLUTION DID TREND SLIGHTLY TOWARD THE GFS IN THE IDEA OF
SQUASHING THE EAST SIDE OF THE UPPER RIDGE A BIT BY WEDNESDAY-
THURSDAY. GIVEN THE UNCERTAINTY AND SPREAD IN SOLUTIONS... WENT
WITH A BLENDED APPROACH WHICH RESULTS IN A LONGER PERIOD OF CHANCE
POPS THAN WHAT WILL LIKELY OCCUR. HOPEFULLY SUBSEQUENT FORECASTS
WILL BE ABLE TO REFINE THE MOST LIKELY LOCATIONS AND TIME PERIODS
FOR PCPN DURING THE PERIOD.
&&
.AVIATION.../06Z TAF ISSUANCE/
SYSTEM THAT BROUGHT RA TO THE AREA THROUGH THIS PAST EVENING
PULLING EAST TONIGHT...WITH PCPN LIKELY OUT OF EAU BY 06Z. MAY BE
A BRIEF MVFR CIG FOR THE FIRST HOUR OR TWO AT EAU...OTHERWISE VFR
CONDITIONS WILL DOMINATE. SFC RIDGE MOVING ACROSS MN WILL LEAD TO
FAIRLY LIGHT WINDS...WITH STRONGEST WINDS EXPECTED INTO THE EARLY
AFTERNOON OVER WI...WHERE CLOSER PROXIMITY TO THE SFC LOW WILL
KEEP THE PRESSURE GRADIENT A BIT STRONGER. OUT IN WRN MN...MID
CLOUDS CURRENTLY OVER NODAK WILL DRIFT INTO WRN MN THROUGH THE
MORNING...WITH 5K TO 10K FT CIGS POSSIBLE THROUGH MUCH OF THE DAY
AT AXN. NEXT SYSTEM WILL BE APPROACHING WRN TERMINALS LATE FRIDAY
NIGHT...WITH NEXT TAF NEEDING TO START THINKING ABOUT PCPN FOR AXN
AND MSP TOWARD THE END OF THEIR RESPECTIVE 12Z TAF PERIODS. WINDS
WILL BASICALLY BE OUT OF THE NORTH THROUGH THE DAY...THOUGH RETURN
FLOW SE WINDS WILL START DEVELOPING OVER MN AFTER 00Z.
KMSP...NO ISSUES EXPECTED THIS TAF PERIOD...WITH MUCH OF THE
AFTERNOON INTO EVENING EXPECTED TO BE SPENT WITH SKC CONDITIONS.
BIGGEST CHALLENGE THIS TAF PERIOD WILL BE TIMING WIND SHIFT OVER
TO THE SE...THOUGH THIS LOOKS TO OCCUR BEFORE TRAFFIC PICKS UP SAT
MORNING.
//OUTLOOK...SATURDAY THROUGH TUESDAY...
SAT...PERIODS OF -SHRA WITH MVFR CIGS/VIS POSSIBLE.
SUN...IFR/MVFR CIGS POSSIBLE THROUGH THE MORNING.
MON-TUE...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
TRH/MPG
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1135 PM CDT THU APR 19 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
/640 PM CDT THU APR 19 2012/
Have made adjustments to timing/areal coverage of evening/overnight
convection based on latest short range convective models and radar
trends. Minimal severe threat this evening. Have updated/adjusted
HWO. SPC meso page still shows decent amount of CIN while surface-
based CAPE in 250-500 range are pretty meager while 0-6km bulk shear
is below marginal values along the frontal boundary. Scattered
elevated showers forming over north central MO should build back to
the southwest with time and become more organized as the region of
elevated lift shifts east.
MJ
&&
.PREV DISCUSSION...
/419 PM CDT Thu Apr 19 2012/
Short Range (Tonight through Saturday)...
Satellite imagery from this afternoon shows the nation under the
influence of a progressive pattern, though some buckling of the
flow is apparent as a trough is seen exiting the Rocky Mountains.
Closer to home, a small shortwave ejected into the Plains ahead of
the primary trough exiting the mountainous west, and helped focus
the morning low level jet across northeast Kansas and northwest
Missouri, which resulted in some morning thunderstorms. Those storms
have since dissipated, leaving our attention focused back to our
west, where a cold front is advancing east across Kansas tied to the
leading shortwave.
Currently the front is located along a line from the tip of
northwest Missouri to Wichita, with a fair amount of cumulus cloud
cover bubbling up ahead of the front. Early afternoon soundings show
little in the way of available CAPE across our section of eastern
Kansas and Missouri, as RUC based analysis indicates there is only
about 500 J/KG of SBCAPE, and given the dry layer at the 700mb level
noted off an early afternoon sounding at KMCI, there was no ability
for the model to evaluate MLCAPE. The lack of instability looks to be
from both the cloud cover in advance of the front, and due to lower
than expected dew points, which have struggled to clime beyond the
low 50s. However, with the front advancing across Kansas, frontogenic
forcing is still expected to use what little CAPE is available late
this afternoon/early this evening to generate some scattered storms
in eastern Kansas. The storms should move northeast, but the line
will struggle to fill in unless more quality moisture can quickly
advect ahead of the front. Shear parameters for this evening are
more than sufficient to generate concerns for severe weather, but
given the lack of instability, and the way surface winds veer off as
the front moves through, and it is looking increasingly difficult for
us to realize any storms that could support much more than marginal
severe weather, which would be limited to large hail and damaging
straight line winds. Heavy rain may occur with some of these storms,
but at this time the lack of quality moisture and the progressive
nature of the front should preclude any widespread flooding threat.
With the continued consensus of the various short range operational
and ensemble models, have persisted in quickly moving the storms to
the east, leaving most of the forecast area dry after 12Z Friday.
Being behind the front Friday will allow for something we have not
seen a whole lot of in the past several months, cold air advection.
The breezy north wind behind the front will actually keep afternoon
highs below normal Friday. However, this cool trend will quickly
fade as southwest winds return for Saturday bringing highs in the 60s
back.
Cutter
Medium Range (Sunday through Thursday)...
No major changes planned to going medium range forecast. Upper
ridge axis forecast to strengthen over western US during early part
of next week while area of surface high pressure builds into
forecast area. By mid-week the upper feature shifts into the
central US. This combined with increasing southerly flow as surface
high moves to the east should provide for a gradual warm up.
Appears that temperatures could approach the 80 degree mark by
Wednesday and then again on Thursday. ECMWF, GFS, and GEM models
hinting at weak mid-level shortwave topping ridge in upper
Mississippi Valley in the Wednesday/Thursday time frame. Not out of
the realm of possibility to see some scattered precipitation over
northern Missouri with this feature. However there are enough
inconsistencies in the timing and geographic placement of the QPF
that dry forecast still appears to be the best way to go at this
time.
MJM
&&
.AVIATION...
For the 06 TAFs...In the wake of the cold frontal passage a large
area of MVFR cigs have overspread all 3 terminals. These cigs will
remain in place through around mid morning before cigs gradually
improve with breaks in the overcast, finally reaching VFR category
by around the noon hour. Gusty northerly winds expected until late
afternoon when clouds clear out and the pressure gradient relaxes.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
349 AM CDT FRI APR 20 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
A PATTERN CHANGE IS IN STORE FOR NEBRASKA THROUGH THIS TIME
PERIOD...GOING FROM FAST FLOW WITH SYSTEMS MOVING THROUGH ALMOST
DAILY TO A BUILDING RIDGE LEADING TO DRIER AND WARMER CONDITIONS.
AT 20.08Z WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH OVER THE
NEBRASKA PANHANDLE WITH RIDGING UPSTREAM IN SOUTHWEST CANADA AND
ANOTHER SHORTWAVE TROUGH PUSHING INTO BRITISH COLUMBIA. GOOD
SUBSIDENCE AND DARKENING WAS SEEN BEHIND THE NEBRASKA
SHORTWAVE...AND WHEN LOOKING AT IR IMAGERY EARLY THIS
MORNING...DID SEE CLEARING SKIES ACROSS THE PANHANDLE AND FAR
WESTERN NEBRASKA. CLOUDS...ALONG WITH SHOWERS REMAINED ACROSS THE
AREA FROM SOUTHWEST TO NORTHEAST...AHEAD OF THE SHORTWAVE.
FOR TODAY THE UPPER LEVEL SHORTWAVE TROUGH WILL DIG
SOUTHEAST OF THE FORECAST AREA...ALLOWING RIDGING TO START BUILDING
INTO THE FORECAST AREA. WITH DECENT SUBSIDENCE BEHIND THE
SHORTWAVE...SHOULD CONTINUE TO SEE SKIES CLEAR...ALTHOUGH IT MAY
TAKE MUCH OF THE MORNING IN SOME PLACES AS LOW LEVEL MOISTURE BELOW
THE INVERSION MAY TAKE SOME TIME TO SCOUR OUT. WITH THE CLOUD
COVER AND WITH TEMPERATURES ALOFT BEING SLOW TO WARM UP...DON/T
EXPECT TEMPERATURES TO RISE TOO HIGH TODAY. LOOKING FOR
HIGHS...EVEN WITH SUN AROUND 60 DEGREES.
ANOTHER DISTURBANCE /THE SHORTWAVE MOVING INTO BRITISH COLUMBIA/
WILL PUSH OVER THE RIDGE TONIGHT AND ON SATURDAY. DUE TO THE RIDGE
BUILDING EAST...THE STORM TRACK WITH THIS NEXT DISTURBANCE SHOULD
STAY NORTH AND EAST OF THE FORECAST AREA. MAY GET SOME CLOUDY
SKIES LATER IN THE DAY AND INTO THE DAY SATURDAY ACROSS NORTH
CENTRAL NEBRASKA. A COLD FRONT WILL BE PUSHED SOUTHEAST ACROSS THE
AREA ON SATURDAY ASSOCIATED WITH THIS SYSTEM. BUT...WITH MOISTURE
STAYING CLOSER TO THE SURFACE LOW OVER THE DAKOTAS AND IOWA...DO
NOT ANTICIPATE THE NEED FOR ANY RAIN CHANCES IN THE FORECAST FOR
TONIGHT OR SATURDAY. THIS WILL NEED TO BE WATCHED THOUGH AS THERE
HAS BEEN THE SUGGESTION FROM A MODEL HERE AND THERE THAT SHOWERS
COULD SNEAK SOUTHWARD AND INTO THE AREA ON SATURDAY.
EVEN WITH THE PASSING OF THE COLD FRONT...TEMPERATURES ALOFT /AT
850MB/ INCREASE BY 4 TO 6 DEGREES FROM 21.00Z TO 22.00Z. SO
LOOKING AT WARMER TEMPERATURES ON SATURDAY...LIKELY IN THE UPPER
60S AND 70S ACROSS THE FORECAST AREA. CLOUD COVER OVER THE
NORTHEAST MAY SLOW WARMING UP AND MAY KEEP HIGHS A BIT
COOLER...BUT LESSER CLOUDS ARE EXPECTED OVER THE SOUTH AND WESTERN
AREAS. SOMETHING IN FAVOR OF WARMING IS THE NORTHWEST SURFACE
FLOW...CAUSING A DOWNSLOPE AND WARMING EFFECT...TO HELP WARMING
INTO THE 70S. WINDS DO LOOK TO BE A BIT BREEZY BEHIND THE PASSING
FRONT ON SATURDAY...BUT SHOULD DIMINISH BY EVENING AS HIGH
PRESSURE BUILDS IN.
THE UPPER LEVEL FLOW AMPLIFIES FURTHER ON SUNDAY AS THE TROUGH
OVER THE EASTERN CONUS DIGS INTO THE DEEP SOUTH AND THE RIDGE
BUILDS OVER THE ROCKIES. TEMPERATURES AT 850MB WILL SEE A DECENTLY
SHARP GRADIENT...VARYING FROM 6C TO 20C AT 23.00Z FROM EASTERN TO
WESTERN NEBRASKA RESPECTIVELY.
.LONG TERM...MONDAY THROUGH THURSDAY
THE WORK WEEK BEGINS WILL WELL ABOVE NORMAL TEMPERATURES AS THE
MODELS CONTINUE TO HAVE A SIMILAR HANDLE ON THE UPPER LEVEL
PATTERN THROUGH TUESDAY. THROUGH THIS TIME...HIGHLY AMPLIFIED FLOW
EXISTS WITH UPPER LOWS OVER BOTH THE EASTERN CONUS AND THE EASTERN
PACIFIC...WITH STRONG RIDGING ACROSS THE WESTERN AND CENTRAL
CONUS.
GFS ENSEMBLE STANDARDIZED ANOMALIES CONTINUE TO SHOW STRONG
SIGNALS FOR WELL ABOVE NORMAL TEMPERATURES FOR MONDAY AND
TUESDAY...WITH TEMPERATURES AT 2 TO 3 STANDARD DEVIATIONS ABOVE
NORMAL FROM MONDAY THROUGH WEDNESDAY. AS STATED LAST NIGHT...DON/T
ANTICIPATE RECORD HIGHS BUT WELL ABOVE NORMAL FOR THIS TIME OF
YEAR. THE SIGNAL IS STILL THERE FOR WEDNESDAY...BUT WITH LESSER
CONFIDENCE DUE TO MODELS BEGINNING TO DIVERGE. DIFFERENCES BEYOND
TUESDAY INCLUDE THE GFS WANTING TO MOVE THE CLOSED UPPER LEVEL LOW
ACROSS THE GREAT BASIN AND INTO THE SOUTHERN PLAINS BY
THURSDAY...WHILE THE ECMWF...GEM AND GFS ENSEMBLE MEAN KEEPS THE
CLOSED LOW OFF THE CALIFORNIA COAST. MEANWHILE IN THE NORTHERN
STREAM...FOR WEDNESDAY SEVERAL SOLUTIONS WOULD SUGGEST A SLIGHT
FLATTENING OF THE RIDGE MEANING THE POSSIBILITY FOR SOME COLD AIR
ADVECTION...AND COOLER TEMPERATURES FOR WEDNESDAY. WILL TAKE A
CONSENSUS APPROACH FOR TEMPERATURES THROUGH THIS TIME AND WILL
KEEP THE FORECAST DRY THROUGH THIS TIME WITH LITTLE CONFIDENCE ON
THE TIMING OF ANY SHORTWAVE MOVING OVER THE RIDGE WITH ENOUGH
STRENGTH TO PUSH PRECIPITATION INTO NEBRASKA.
&&
.AVIATION...
THE BANK OF MVFR/LOCAL IFR CIGS ACROSS NCNTL NEB IS EXPECTED TO
CONTINUE TO ERODE THROUGH 18Z THIS MORNING. VFR IS GENERALLY
EXPECTED AFTER 18Z THROUGH 12Z SATURDAY MORNING.
ONE CAVEAT IS THAT THE RUC WHICH RUNS THROUGH ONLY 18Z THIS MORNING
SHOWS A NARROW AREA OF MVFR ALONG HWY 83 LINGERING AT 18Z. THE OTHER
MODELS SUGGEST VFR AT THIS TIME. THUS LOCAL MVFR CONDITIONS ARE
POSSIBLE 18Z THROUGH 21Z WITH VFR THEREAFTER.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...BROOKS
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
131 AM EDT FRI APR 20 2012
.SYNOPSIS...
A NEARLY STATIONARY FRONT LOCATED JUST OFFSHORE WILL DISSIPATE
FRIDAY. LOW PRESSURE IS EXPECTED TO DEVELOP IN THE NORTHERN GULF OF
MEXICO SATURDAY...MOVING UP THE SOUTHEAST ATLANTIC COAST ON SUNDAY
WITH A SIGNIFICANT RAIN EVENT POSSIBLE FOR AT LEAST THE COASTAL
CAROLINAS. HIGH PRESSURE WILL BUILD IN FROM THE WEST THROUGH THE
MIDDLE OF NEXT WEEK WITH DRY WEATHER AND BELOW-NORMAL TEMPERATURES.
&&
.NEAR TERM /THROUGH 6 AM EDT FRIDAY/...
AS OF 130 AM FRIDAY...PREVIOUS FORECAST REMAINS IN EXCELLENT SHAPE
AND FEW CHANGES WERE NEEDED EARLY THIS MORNING. PREVIOUS DISCUSSION
FROM 10 PM FOLLOWS...
LATEST 88D PCPN COVERAGE WIDELY SCATTERED AT THE MOMENT. COASTAL
COUNTIES WILL REMAIN UNDER THE THREAT FOR SHRA INTO THE PRE-DAWN HRS
OF FRIDAY. THE HRRR SEEMS TO BE HANDLING THIS PCPN MUCH BETTER THAN
ORIGINALLY THOUGHT. THE WEAK MID LEVEL S/W MOVING OFFSHORE JUST
SOUTH OF THE ILM CWA SEEMS TO HAVE THE AVAILABLE DYNAMICS TO AID IN
THE GENERATION OF PCPN ALONG THE IMMEDIATE COAST AND THEIR ADJACENT
ATL WATERS. 00Z MHX AND CHS RAOBS ILLUSTRATE NEARLY SATURATED
CONDITIONS SFC THRU 800MB. THE OVERCAST LOW LEVEL STRATUS CLOUD DECK
TO BECOME THE DOMINATE SKY CONDITION FOR THE REMAINDER OF THE
OVERNIGHT. WITH REFERENCE TO FOG POTENTIAL...THE GFS MODEL MOS
GUIDANCE INDICATES WIDESPREAD FOG WITH POCKETS OF DENSE...AND IS
FAVORED OVER THE NAM MOS WHICH INDICATES A MUCH LOWER THREAT FOR
FOG.
LOOKING AT LOW LEVEL PROGGED PARTIAL THICKNESSES AND 8H PROGGED
TEMPS...NO ADDITIONAL CAA IS EXPECTED...IN FACT IT FAVORS A NEUTRAL
TEMP ADVECTION DURING THE REMAINDER OF THE OVERNIGHT. TONIGHTS MINS
REMAIN UNCHANGED...WHICH REMAINS ON THE HIGHER SIDE OF MOS
GUIDANCE.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...A FLAT H5 RIDGE ACROSS THE SOUTHEASTERN UNITED
STATES ON FRIDAY WILL LIFT EAST ON SATURDAY AS A LARGE UPPER LOW
BEGINS TO TAKE SHAPE OVER THE NORTHERN GULF OF MEXICO. THE LOW WILL
EJECT AN IMPULSE UP THE COAST SATURDAY NIGHT RESULTING IN INCREASING
CHANCES FOR CONVECTION...ESPECIALLY LATER IN THE SHORT TERM PERIOD.
AT THE SURFACE...LOW PRESSURE IS EXPECTED TO RIDE UP JUST OFF THE
COAST SATURDAY NIGHT...THUS THE HIGHEST QPF AMOUNTS ARE EXPECTED TO
BE ALONG THE COASTAL COUNTIES. MAV/MET NUMBERS ARE RELATIVELY CLOSE
THROUGH THE PERIOD...AND SAW NO REASON AT THIS TIME TO STRAY TOO FAR
FROM THEM. THESE TEMPERATURES WILL RANGE ABOVE NORMAL EACH PERIOD
AHEAD OF THE AFOREMENTIONED DEVELOPING UPPER LOW.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...MEDIUM RANGE MODELS APPEAR TO BE DIVIDING INTO
TWO CAMPS REGARDING THE SIGNIFICANT SYSTEM FOR LATE IN THE WEEKEND
EXTENDING INTO EARLY NEXT WEEK. THE OPERATIONAL GFS IS ADVERTISING
AN EVER INCREASING PROGRESSIVE TREND WITH THE MID LEVEL LOW WHILE
THE GFS PARALLEL (GFS EXPERIMENTAL MODEL) IS SLOWER AND MORE IN LINE
WITH THE ECMWF SUITE OF PRODUCTS.
WILL CONTINUE TO FOLLOW THE HPC FAVORED SLOWER SOLUTION AS IT OFFERS
MORE CONTINUITY WITH PREVIOUS FORECAST. LARGE SWATH OF MOISTURE
EXPECTED TO INUNDATE THE FORECAST AREA SUNDAY WITH MID LEVEL
DEFORMATION BEING THE DRIVING FORCE.
THE REMAINDER OF THE FORECAST...FROM MONDAY ON IS DRY WITH
TEMPERATURES BELOW CLIMATOLOGY AT LEAST THROUGH WEDNESDAY. MIXED
BOUNDARY LAYER SHOULD KEEP TEMPERATURES IN THE MIDDLE 40S TUESDAY
MORNING WITH A MODIFYING AIRMASS BUT MORE CONDUCIVE RADIATIONAL
CONDITIONS YIELDING A DEGREE OR TWO LOWER WEDNESDAY MORNING. DAYTIME
HIGHS...SOMEWHAT BELOW CLIMATOLOGY EARLY WILL QUICKLY MODERATE TO
SEASONAL NORMALS BY WEDNEDAY AND THURSDAY.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...A RATHER DIFFICULT AND LOW-CONFIDENCE FORECAST SHAPING
UP THROUGH THIS MORNING. MVFR STRATUS COVERS MUCH OF THE EASTERN
CAROLINAS CURRENTLY. WE ARE ON THE "COLD" SIDE OF A WEAK STATIONARY
FRONT THAT IS DISSIPATING ABOUT 60-100 MILES OFFSHORE. 00Z MODEL
GUIDANCE INITIALIZED POORLY AS IT SHOWS WE SHOULD HAVE WIDESPREAD
IFR CIGS CURRENTLY. THE STRATUS BASES SHOULD DROP SLOWLY OVER THE
NEXT FEW HOURS WITH IFR CIGS POTENTIALLY DEVELOPING BETWEEN
07-10Z...FIRST AT ILM THEN SPREADING SOUTH AND WEST THROUGH THE
MYRTLE BEACH VICINITY AND EVENTUALLY TO FLO. OUR CONFIDENCE REMAINS
LOW HOWEVER AS LOCAL CLIMATE TOOLS SHOW LIGHT NE SFC WINDS AND MVFR
CIGS DO NOT OFTEN RESULT IN WIDESPREAD IFR THIS TIME OF YEAR.
AFTER DAYBREAK ANY IFR CIGS WILL RISE TO AN MVFR BKN LAYER BY
15Z...THEN SCATTERING OUT THIS AFTERNOON AS EAST AND SOUTHEAST SFC
WINDS DEVELOP THROUGHOUT THE REGION FORMERLY OCCUPIED BY THE OLD
DECAYED FRONT.
EXTENDED OUTLOOK...MVFR/POSSIBLE IFR CONDITIONS FRI NIGHT IN FOG AND
LOW STRATUS...THEN AGAIN IN SCATTERED SHOWERS SATURDAY. NUMEROUS
SHOWERS/TEMPO IFR POSSIBLE SUNDAY...MAINLY NEAR THE COAST. VFR
MONDAY AND TUESDAY WITH ISOLATED SHOWERS MONDAY.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 AM FRIDAY...VIRTUALLY NO CHANGES TO THE PREVIOUS FORECAST
WHICH IS IN EXCELLENT SHAPE EARLY THIS MORNING. PREVIOUS DISCUSSION
FROM 10 PM FOLLOWS...
COLD FRONT LIES NEARLY STATIONARY JUST E AND S OF THE ILM COASTAL
WATERS. NORTHEAST TO EAST 10-15 KT WINDS WILL PREMIERE ACROSS ALL
ILM WATERS OVERNIGHT...WITH A BRIEF WINDOW OF SUSTAINED 15 KT DUE TO
THE SLIGHTLY PINCHED SFC PRESSURE GRADIENT. SIGNIFICANT SEAS WILL
PRIMARILY BE DRIVEN TONIGHT BY A SOLID EASTERLY 1-2 FOOT GROUND
SWELL EXHIBITING 12 TO 14 SECOND PERIODS. THE ADDITION OF THE
LOCALLY PRODUCED WIND DRIVEN WAVES TO SIGNIFICANT SEAS...WILL
COMBINE WITH THE SWELL TO YIELD AN OVERALL 2 TO 4 FT SIG. SEAS.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...THE WEAK FRONT OVER THE WATERS FRIDAY MORNING
WILL GRADUALLY DISSIPATE. THE FLOW WILL BECOME SOUTHERLY DURING THE
AFTERNOON AFTER THE FRONT DISSOLVES. THE SOUTHERLY PRESSURE GRADIENT
WILL KEEP SOUTHERLY FLOW AROUND 15 KNOTS OR LESS SATURDAY INTO
SATURDAY EVENING. THEN WITH POSSIBLE LOW BEGINNING TO RIDE UP THE
COAST THE FLOW MAY BACK OVERNIGHT SATURDAY NIGHT. SEAS WILL BE
DOMINATED BY AN EASTERLY SWELLS FRIDAY. THE SWELLS WILL GRADUALLY
WEAKEN AND BECOME OVERTAKEN BY HIGHER FREQUENCY SOUTHERLY WAVES
SATURDAY.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...MAIN FORECAST CHALLENGE WILL BE WIND
DIRECTIONS EARLY IN THE PERIOD AS A COASTAL FRONT WILL BE MEANDERING
SOMEWHERE IN THE AREA. VIA HPC GRAPHICS...START OUT THE PERIOD WITH
SOUTH TO SOUTHEAST WINDS QUICKLY BACKING TO NORTHEAST BY THE EARLY
AFTERNOON SUNDAY AS LOW PRESSURE MOVES OFFSHORE AND UP THE COAST.
NORTH TO NORTHWEST WINDS FROM LATE SUNDAY ON WITH SPEEDS GENERALLY
AROUND 15 KNOTS. A SECONDARY SHORTWAVE IN THE NORTHWEST FLOW ALOFT
WILL INCREASE WINDS SLIGHTLY LATE TUESDAY. WAVEWATCH SEAS LOOK GOOD
WITH 3-5 FEET EARLY DECREASING TO 2-4 FEET MONDAY AND TUESDAY WITH
THE OFFSHORE FLOW.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...DCH/TRA
SHORT TERM...SRP
LONG TERM...SHK
AVIATION...TRA
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
406 AM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD INTO THE AREA
SATURDAY NIGHT AND THEN WEAKEN SUNDAY. A SURFACE LOW AND UPPER LOW WILL
MOVE SOUTH TO NORTH OVER THE EASTERN UNITED STATES EARLY NEXT WEEK
AND THIS WILL AFFECT THE WEATHER ESPECIALLY OVER NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE SPRINKLES THAT ARE OVER NORTHWEST OHIO AND NORTH OF LAKE ERIE ARE
DECREASING AS THEY MOVE EAST. WILL NOT MENTION THEM IN THE
ZONES/GRIDS. WILL ISSUE A NOWCAST AS NEEDED.
THE ISSUE FOR THIS AFTERNOON IS THE TIMING OF THE PRECIPITATION. THE
MODELS AND CURRENT CONDITIONS INDICATE THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE VERY CLOSE TO THE FRONT AND BEHIND IT. THE
FRONT IS EXPECTED TO BE FROM TOL TO FDY AROUND 20Z...CLE TO MFD AT
00Z AND ERI TO YNG BY 03Z. THE HRRR MODEL IS TRYING TO INDICATE SOME
SHOWERS DEVELOPING WAY AHEAD OF THE FRONT. MOST OF THE MODELS ARE
NOT INDICATING THIS...SO PLAYED THE FORECAST THAT WAY. SPC HAS SOME
OF THE AREA IN SEE TEXT FOR POSSIBLE SEVERE THUNDERSTORMS. EXPECTING
A FAIR AMOUNT OF CUMULUS CLOUDS THIS AFTERNOON...WE SHOULD HAVE SOME
SUNSHINE TO HELP INCREASE THE CAPES TOO MUCH. WILL MENTION IN THE HWO
STRONG TO AN ISOLATED SEVERE THUNDERSTORM COULD BE POSSIBLE. THE
BEST CHANCE FOR THUNDERSTORMS WILL BE WITHIN A FEW HOURS OF
FRONTAL PASSAGE. WITH THE SOUTHWEST FLOW AND SOME SUNSHINE WENT
TOWARD THE WARMEST GUIDANCE. ATTM WITH NOT 100% SUNSHINE WE SHOULD
NOT BREAK ANY RECORDS...THE RECORD HIGHS FOR TODAY ARE IN THE
LOWER TO MID 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
THE GFS/ECMWF HANG UNTO THE SHOWERS MUCH LONGER THAN THE OTHER
MODELS. THIS SEEMS REASONABLE WITH A FAIR AMOUNT OF OMEGA AND THE
UPPER TROF MOVING THROUGH TONIGHT AND SATURDAY. HIGH PRESSURE
RIDGE TRIES TO BUILD IN SATURDAY NIGHT AND WEAKEN BY SUNDAY...SO
SATURDAY NIGHT AND SUNDAY SHOULD BE DRY. MAY HAVE TO WORRY ABOUT
SOME FROST SATURDAY NIGHT IF THE WINDS DECREASE ENOUGH AS THE
CLOUDS WILL DECREASE.
SUNDAY NIGHT THROUGH MONDAY NIGHT ARE INTERESTING WITH THE SURFACE LOW
AND UPPER LOW MOVING SOUTH TO NORTH OVER THE EASTERN UNITED
STATES. INTRODUCING CHANCE POPS OVER THE EASTERN PORTION OF THE
FORECAST AREA AND WITH THE AIR COLD ENOUGH A CHANCE OF RAIN OR
SNOW. NORTHWEST OHIO SHOULD REMAIN MAINLY DRY FROM THE
SYSTEM...THIS WILL HAVE TO BE WATCHED.
TENDED ON THE COOLER SIDE FOR THE TEMPERATURES.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A LOT OF UNCERTAINTY FROM TUESDAY ONWARD WITH THE FORECAST. TUESDAY
WILL DEPEND ON WHAT ENDS UP HAPPENING WITH THE EAST COAST LOW THAT
IS FORECAST TO CROSS NEW ENGLAND. HOW MUCH COLD/COOL AIR WILL BE
DRAWN SOUTHWARD WITH THIS. WITH A COUPLE RUNS WITH THIS GENERAL
SOLUTION HAVE LOWERED HIGH TEMPS ON TUESDAY AND WEDNESDAY AND THEY
WILL BE SITTING 5 TO 10 DEGREES BELOW NORMAL. THERE IS A LOT OF
SWING IN WHICH WAY THIS WILL TURN OUT. EVENTUALLY TOWARD MID WEEK WE
WILL BE IMPROVING AS WE START TO GET SOME RIDGING BUILD TOWARD THE
AREA.
&&
.AVIATION /08Z FRIDAY THROUGH TUESDAY/...
VFR THROUGH THE FIRST HALF OF THE TAF WITH INTERVALS OF MID/HIGH
CLOUDS. SHOULD DEVELOP SOME 5K CU FOR THIS AFTERNOON. GUSTS WILL
PICK UP LATE MORNING AND WILL BE AROUND 25 KNOTS TODAY...WITH A
FEW 30 KNOT GUSTS POSSIBLE. THE THE BULK OF THE SHOWERS/RAIN WILL
BE IMMEDIATELY BEHIND THE FRONT TO CROSS THE AREA LATE THIS
AFTERNOON AND EVENING. THERE IS SOME CHANCE OF A FEW
ISOLATED/SCATTERED SHRA/TS DEVELOPING AHEAD OF THE FRONT WEST OF
CLE/MFD IN PEAK HEATING...BUT FOCUSED TAFS ON THE MORE WIDESPREAD
CONDITIONS BEHIND THE FRONT. DEFINITE MVFR...WITH GOOD CHANCES OF
IFR TOO. EMBEDDED THUNDER ALSO POSSIBLE AT LEAST INITIALLY/EARLY.
FRONT SLOWS WITH TIME AND RAIN WILL TAKE MOST OF THE NIGHT TO GET
THROUGH CLE AND INTO SATURDAY MORNING FURTHER EAST.
.OUTLOOK...NON VFR LIKELY FRIDAY NIGHT INTO SATURDAY MORNING AND
AGAIN FOR THE EAST MONDAY INTO TUESDAY.
&&
.MARINE...
COLD FRONT TO COME ACROSS THE LAKE THIS EVENING. SOUTHERLY FLOW
ACROSS A STABLE LAKE WILL KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA
FOR TODAY. ENOUGH POST-FRONTAL WIND TO MAKE FOR A CHOPPY NEARSHORE
LATE TONIGHT THROUGH SATURDAY MORNING...AND A SMALL CRAFT ADV WILL
LIKELY BE NEEDED THEN. HIGH PRESSURE THEN SETTLES OVER THE NORTHERN
PLAINS/WESTERN LAKES INTO EARLY NEXT WEEK WHILE AN EAST COAST LOW
TRACKS TOWARD AND ACROSS NEW ENGLAND. THIS WILL AT LEAST TIGHTEN UP
THE GRADIENT AND WILL LIKELY HAVE ANOTHER PERIOD OF SMALL CRAFT
CONDITIONS FROM MONDAY INTO TUESDAY. NORTHERLY FLOW THIS WEEKEND AND
DEPENDING ON TRACK OF THE EAST COAST LOW...POSSIBLY BACKING TO
NORTHWEST FOR EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
416 AM CDT FRI APR 20 2012
.SHORT TERM (TODAY THROUGH SATURDAY)...MAIN FORECAST CONCERN IS
WITH THUNDER AND SEVERE POTENTIAL TODAY. SURFACE LOW CURRENTLY
OVER NORTHERN ILLINOIS WITH COLD FRONT DRAPED INTO WEST TEXAS
WILL PROGRESS EASTWARD TODAY. AHEAD OF THE FRONT SOUTH TO
SOUTHEAST SURFACE WINDS AND SOUTH TO SOUTHWEST WINDS AT H850 WILL
ALLOW FOR GOOD HEATING TODAY. H850 WINDS WILL ALSO KEEP A PRETTY
STRONG CAP IN PLACE FOR MUCH OF THE DAY...HAMPERING PRECIPITATION.
ANYTHING THAT WOULD DEVELOP THIS MORNING AND EARLY AFTERNOON
SHOULD JUST REMAIN SHOWER ACTIVITY. THE FRONT MOVES IN BY MID
AFTERNOON WIPING OUT THE CAP AND BRINGING A BRIEF WINDOW FOR
SEVERE WEATHER POTENTIAL. MOST MODELS ARE PEAKING CAPE ACROSS THE
AREA AROUND 1500-2000 J/KG THIS AFTERNOON...ALTHOUGH THE RUC AND
SOME MESO MODELS ARE A BIT HIGHER THAN THIS...ESPECIALLY EAST.
CONSENSUS FOR CONVECTIVE INITIATION SEEMS TO BE IN THE 20-21Z TIME
FRAME ALONG THE COLD FRONT WHERE CIN RAPIDLY DECREASES. LAPSE
700-500 LAPSE RATES LOOK FAVORABLE AND LI VALUES DECREASE TO AS
MUCH AS -8 DEPENDING ON THE MODEL. THE BIGGEST DETERRENT THOUGH MAY
BE THE SOUTHWESTERLY 850 MB WINDS. THIS COULD POTENTIALLY MAKE THE
CAP STRONG ENOUGH TO NOT ERODE BEFORE THE UPPER TROUGH MOVES
THROUGH...AND IT COULD ALSO BRING TOO MUCH DRY AIR IN...DEPENDING
ON THE DEPTH OF THESE SOUTHWEST WINDS. ADDITIONALLY...PWAT VALUES
ARE LESS THAN IMPRESSIVE FOR THE ENTIRE AREA...WITH MAINLY 1 TO
1.5 INCH VALUES EXPECTED.
WHILE THE ENTIRE FORECAST AREA HAS THE CHANCE TO SEE SEVERE
WEATHER...MAINLY A WIND AND HAIL THREAT...THE BEST CHANCE WILL BE
IN THE NORTHEAST PORTION OF THE FORECAST AREA...AND BETWEEN 21 AND
00Z.
THE UPPER TROUGH HANGS BACK A BIT, BUT SHOULD STILL MOVE
THROUGH BETWEEN 00 AND 06Z QUICKLY ENDING PRECIP CHANCES ACROSS
THE AREA. ONCE THE UPPER TROUGH GETS OUT OF HERE PLEASANT...BUT
BREEZY CONDITIONS WILL FILTER IN. TEMPERATURES SHOULD COOL NICELY
OVERNIGHT FRIDAY NIGHT INTO SATURDAY MORNING WITH TEMPS DECREASING
INTO THE 50S FOR MUCH OF THE AREA. SATURDAY LOOKS TO WARM BACK
INTO THE UPPER 70S AND 80S...BUT WITH MUCH LOWER DEWPOINTS.
&&
.MARINE...BEHIND THE COLD FRONT FRIDAY NIGHT STRONG OFFSHORE FLOW
WILL DEVELOP. WITH WARM SURFACE WATER TEMPERATURES GUSTS SHOULD
MIX DOWN PRETTY EASILY. THIS WILL LIKELY BRING NEAR GALE FORCE
GUSTS TO THE AREA BETWEEN 06Z AND 18Z SATURDAY. WILL HOLD OFF ON
ISSUING A GALE WATCH AT THIS TIME...BUT ONE MAY BE NEEDED LATER
TODAY. AT LEAST A SMALL CRAFT ADVISORY IS LIKELY.
&&
.LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)...UPPER LEVEL TROUGH WILL
BE EAST OF THE AREA TO START THE EXTENDED PART OF THE FORECAST.
DRIER AIR WILL BE ENTRENCHED OVER SOUTH TEXAS AS PRECIPITABLE WATER
VALUES FALL BELOW 0.75 INCHES. WITH WINDS BECOMING LIGHTER INLAND
AND THE DRY AIR...ANTICIPATE DECENT RADIATIONAL COOLING SATURDAY
NIGHT WITH TEMPS FALLING INTO THE LOWER/MID 50S ACROSS MUCH OF THE
REGION. A DRY NORTHWEST FLOW ALOFT WILL PREVAIL INTO EARLY NEXT WEEK
AS UPPER LEVEL RIDGE BECOMES ESTABLISHED ACROSS THE ROCKIES. SURFACE
HIGH WILL SHIFT TO THE EAST ON TUESDAY WITH ONSHORE FLOW RETURNING.
TEMPS WILL MODERATE THROUGH THE WEEK...WITH LOWER 90S ACROSS THE
WEST TO LOWER/MID 80S NEAR THE COAST WEDNESDAY THROUGH FRIDAY.
LATEST RUN OF THE GFS BREAKS THE UPPER RIDGE DOWN ON THURSDAY BUT
THE EURO KEEPS UPPER TROUGH OUT WEST THROUGH THE PERIOD. FORECAST
WILL CONTINUE TO FAVOR AMPLIFIED UPPER RIDGE SOLUTION FOR THE TIME
BEING. NO SIGNIFICANT CHANGES MADE TO THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 81 58 78 53 82 / 40 30 0 0 0
VICTORIA 80 54 76 50 79 / 50 30 0 0 0
LAREDO 90 63 85 58 89 / 20 10 0 0 0
ALICE 85 55 81 52 83 / 30 20 0 0 0
ROCKPORT 79 60 79 57 78 / 40 40 0 0 0
COTULLA 87 55 82 50 85 / 20 10 0 0 0
KINGSVILLE 83 58 79 52 83 / 40 30 0 0 0
NAVY CORPUS 79 62 78 61 78 / 40 40 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
PZ/83...SHORT TERM
TB/78...LONG TERM
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1141 PM CDT THU APR 19 2012
.AVIATION...
OUTFLOW FROM STORMS OVER NORTHWEST COUNTIES PUSHED INTO THE METROPLEX
WHILE WEAKENING WITH TIME. AFTER A BRIEF SHIFT AROUND TO
THE NORTH...WINDS SHOULD PICK BACK UP OUT OF THE SOUTH TO
SOUTHEAST AHEAD OF A COLD FRONT. THE FRONT CONTINUES TO TRUDGE
SOUTHEAST THROUGH OKLAHOMA AND NORTHWEST TEXAS...AND IS EXPECTED
TO REACH THE DALLAS-FORT WORTH METROPLEX AROUND 8 AM....AND THE
WACO AREA A COUPLE OF HOURS LATER. STORMS REMAIN ACTIVE ALONG AND
IMMEDIATELY BEHIND THE FRONT...AIDED BY A SHARPENING TROUGH WHICH
CONTINUES TO DIVE SOUTHEAST THROUGH THE CENTRAL PLAINS.
ISOLATED SHOWERS AND STORMS ARE A SLIM POSSIBILITY OVERNIGHT ASSOCIATED
WITH MESOSCALE BOUNDARIES AHEAD OF THE MAIN FRONT. WILL NEED TO
KEEP AN EYE ON NEW ACTIVITY DEVELOPING OVER WESTERN COUNTIES AS IT
WOULD APPROACH THE FORT WORTH AREA FROM THE WEST IN A FEW HOURS IF
IT HOLDS TOGETHER. WILL KEEP AT LEAST A VCSH FOR MUCH OF THE
OVERNIGHT HOURS...WITH THE POSSIBILITY OF ADDING THUNDER IF NEW
CELLS TO THE WEST CONTINUE TO INTENSIFY. WILL ALSO MENTION THUNDER
AROUND THE TIME OF FROPA IN THE MORNING. WINDS WILL SHIFT TO THE
NORTH BEHIND THE FRONT AND BECOME A BIT GUSTY BY MIDDAY. VFR
CONDITIONS AND LIGHTER WINDS CAN THEN BE EXPECTED FRIDAY EVENING
AS HIGH PRESSURE SLIDES IN ACROSS THE REGION.
30
&&
.UPDATE...
DUE TO THE NEARLY DRY ADIABATIC LAPSE RATES AND THE STRONG FORCING
THAT WILL BE OVERSPREADING THE REGION FROM THE NORTHWEST
TONIGHT...THE CONVECTIVE FORECAST IS HIGHLY SENSITIVE TO THE
AMOUNT OF MOISTURE AVAILABLE IN THE MID LEVELS...SPECIFICALLY
MOISTURE NEAR 700 MB. THE 00Z SOUNDING DATA FROM AROUND THE REGION
SHOWED THE MID LEVELS TOO DRY FOR CONVECTION AT FWD/DRT/MAF...BUT
INDICATED AMPLE MOISTURE AT AMA. TONIGHT/S FORECAST WOULD BE EASIER
IF WE HAD ANOTHER SOUNDING NEAR ABILENE...BUT WE DO NOT...SO WE
WILL HAVE TO INFER THAT GIVEN THE EXTENSIVE ACCUS FIELD THAT
DEVELOPED EARLIER...THAT THE MOISTURE IS AVAILABLE. THE RUC IS
PARTICULARLY AGGRESSIVE WITH INDICATING A POCKET OF MOISTURE FROM
SJT-ABI-SPS THAT WILL MOVE EASTWARD INTO THE WESTERN AND CENTRAL
ZONES LATER TONIGHT. THIS SOLUTION IS ALSO SUPPORTED BY THE HRRR.
THUS I THINK THERE ARE ENOUGH INDICATIONS THAT THIS POCKET OF
700MB MOISTURE DOES EXIST...AND AS IT ARRIVES INTO THE AREA LATER
TONIGHT...SHOULD RESULT IN AN INCREASE IN ELEVATED SHOWERS AND
STORMS ACROSS THE WESTERN ZONES. ACTIVITY SHOULD SPREAD EAST INTO
THE CENTRAL ZONES EARLY FRIDAY MORNING. HAVE INCREASED POPS TO
30-40 PERCENT ACROSS THE WESTERN AND CENTRAL ZONES. MARGINALLY
SEVERE HAIL WILL BE POSSIBLE WITH THE STRONGEST CELLS.
OTHERWISE...SMALL LINE SEGMENT OF STRONG/SEVERE CONVECTION OVER
THE NW ZONES WILL CONTINUE TO TRACK EAST ACROSS THE NORTHERN TWO
ROWS OF COUNTIES THROUGH THE LATE EVENING HOURS. AGAIN MARGINALLY
SEVERE HAIL IS THE MAIN THREAT WITH THESE ELEVATED STORMS...BUT
SUB CLOUD EVAPORATION MAY PROMOTE A LOW WIND THREAT AS WELL.
TR.92
&&
.PREV DISCUSSION... /ISSUED 315 PM CDT THU APR 19 2012/
THE NEXT 24 HOURS APPEAR TO BE THE MOST ACTIVE OVER THE NEXT 7
DAYS. THIS AFTERNOON A COLD FRONT EXTENDS ACROSS CENTRAL KANSAS
INTO WESTERN OKLAHOMA AND INTO THE TEXAS PANHANDLE. A DRYLINE IS
LOCATED ALONG A LINE FROM A SURFACE LOW NEAR CHILDRESS TO BIG
SPRING AND INTO THE BIG BEND REGION. A S/W TROF CURRENTLY DIGGING
ACROSS MONTANA AND WYOMING WILL DEEPEN OVER THE NEXT 12 HOURS IN
RESPONSE TO UPSTREAM RIDGE AMPLIFICATION OVER THE WEST COAST.
LATER TONIGHT...THE COLD FRONT WILL SLIDE FARTHER SOUTH AS MAIN
SURFACE LOW OVER THE MIDWEST CONTINUES NORTHEAST. THE ATMOSPHERE
ACROSS NORTH TEXAS AND SOUTHERN OKLAHOMA IS UNSTABLE HOWEVER IT
REMAINS STRONGLY CAPPED TO SURFACE BASED CONVECTION AND IS
EXPECTED TO REMAIN SO FOR MUCH OF THE EVENING. AS HEIGHT
FALLS/LARGE SCALE FORCING FOR ASCENT CONTINUES TO OVERSPREAD THE
SOUTHERN PLAINS TONIGHT...FORCING ALONG THE FRONT IS EXPECTED TO
INCREASE AND BECOME SUFFICIENT FOR THUNDERSTORMS TO DEVELOP
PRIMARILY ACROSS THE FAR NORTHWEST COUNTIES. FORECAST SOUNDINGS
ACROSS NORTHWEST PORTIONS OF THE CWA INDICATE THAT PARCELS FORCED
BETWEEN 800-700MB WILL HAVE LITTLE INHIBITION BETWEEN 10 PM AND
MIDNIGHT. SHEAR PROFILES WILL SUPPORT SUPERCELL STRUCTURES WITH
ANY STORMS THAT CAN DEVELOP DURING THIS TIME...HOWEVER THE PRIMARY
SEVERE WEATHER THREAT WILL BE LARGE HAIL GIVEN THE NEARLY DRY
ADIABATIC MID LEVEL LAPSE RATES AND HIGH LCL/S. FARTHER SOUTH NEAR
THE METROPLEX...STRONG INHIBITION WILL LIKELY REMAIN IN PLACE AND
CONVECTION WILL LIKELY HAVE TO WAIT ON THE FRONT. WILL HAVE THE
HIGHEST POPS RIGHT ALONG THE RED RIVER TAPERING OFF QUICKLY TO THE
SOUTH FOR TONIGHT.
COLD FRONT WILL MOVE THROUGH NORTH TEXAS TOMORROW MORNING WITH
CAPPING ERODING BY THIS TIME. SCATTERED SHOWERS AND THUNDERSTORMS
ARE EXPECTED RIGHT ALONG AND BEHIND THE FRONT. BEST CHANCES WILL
BE ACROSS THE NORTHEAST AND EAST DURING THE MORNING...THEN SHIFT
TO THE SOUTHEAST COUNTIES BY EARLY AFTERNOON AS THE FRONT
PROGRESSES SOUTHWARD. RAIN AND THUNDERSTORMS WILL CLEAR THE CWA BY
TOMORROW EVENING WITH HIGH PRESSURE BUILDING IN AND COOLER
TEMPERATURES EXPECTED. HIGHS ON SATURDAY WILL ONLY BE IN THE LOW
70S WITH LOWS IN THE MID TO UPPER 40S.
THE WEEKEND AND MUCH OF NEXT WEEK LOOKS VERY QUIET WITH LITTLE
CHANCE FOR RAIN AND PLEASANT TEMPERATURES. MID LEVEL RIDGING LOOKS
LIKE IT WILL REMAIN IN PLACE FOR SEVERAL DAYS. THE GFS DOES INDICATE
AN AXIS OF MOISTURE AND INSTABILITY WORKING NORTH INTO THE SOUTHERN
PLAINS BY MIDWEEK WITH MODERATE NORTHWEST FLOW ALOFT. AT THIS TIME
SEE NO SIGNIFICANT SYSTEM THAT WILL BE SUFFICIENT TO INITIATE
CONVECTION BUT WILL CONTINUE TO MONITOR.
DUNN
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 60 70 47 71 50 / 30 60 5 0 0
WACO, TX 62 71 45 73 44 / 20 50 5 0 0
PARIS, TX 58 66 46 69 47 / 50 60 10 0 0
DENTON, TX 58 67 45 69 48 / 40 50 5 0 0
MCKINNEY, TX 60 68 46 70 48 / 40 60 5 0 0
DALLAS, TX 61 70 47 71 50 / 30 60 5 0 0
TERRELL, TX 60 69 45 72 46 / 20 60 5 0 0
CORSICANA, TX 62 71 47 73 48 / 20 60 10 0 0
TEMPLE, TX 62 74 46 74 46 / 20 50 10 0 0
MINERAL WELLS, TX 58 70 44 72 46 / 40 40 5 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
30/92
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1040 PM PDT Thu Apr 19 2012
.SYNOPSIS...
Widespread light rain will overspread the region tonight...with
unsettled...breezy and showery conditions lingering through
Friday. Warmer than average temperatures are expected over the
weekend with mostly dry conditions Saturday but with the
possibility of afternoon thunderstorms by Sunday and Monday. A
return to more seasonal temperatures is expected as a cold front
arrives Tuesday.
&&
.DISCUSSION...
Evening Update: A very moist storm system is bearing down on
the Inland NW with a 1.2" precipitable water fetch slamming into
the coast and warm sector rain already observed or soon to be
observed at most observations. The heaviest rainfall as of 830PM
was noted across the central Columbia Basin along the leading warm
front where we are observing rainfall rates of 0.02-0.05"/hour.
The 02z RUC appeared to capture this enhanced pcpn well on its
295K isentropic charts which in conjunction with the latest radar
loop will continue to expand and march toward the Idaho Panhandle
well before 06z. As such, forecast PoPs have been raised into the
80-100% range with QPF amts incr near a tenth across the eastern
Columbia Basin...Palouse...and West Plains. Behind the warm front,
there is some midlevel drying and backing of winds more to the sw
from s allowing a pseudo rain shadow in the lee of the central
Cascades and Wenatchee area and despite the continued rain
falling, ceilings have been on the rise during the last few hours.
This shadow will continue to incr overnight as pressure falls
strengthen over southern Alberta we incr the westerly component to
midlevel flow...however with the main surface low driving this
moisture and frontal structures into the region lifting northward
along the central BC coast...the main cool occlusion never really
dips south of highway 2 and basically gets hung up across the
region in a sw to ne fashion leading to low confidence that
communities in the lee of the Cascades will remain completely dry.
There is strong agreement that the incr west/southwest flow will
lead to a very wet 6-12z period for the Idaho Panhandle and far
eastern reaches of WA due to enhanced upsloping component. As
such, I have trend QPF amts and PoPs upward. The good news is that
we remain in a relative warm sector through much of the event and
we are not expecting surprising convective bands capable of the
1.00" or greater QPF amts were saw with a flooding event over the
Palouse on March 25/26. On that same note, snow levels which are
roughly 5K north to 6-7K ft south are expected to continue to rise
enhancing snowmelt processes...which will lead to rises across
most basins; especially the St Joe where an RVS has been issued.
/sb
&&
.AVIATION...
06Z TAFs: Satellite reveals a rich tap of subtropical moisture
aimed into the region this eveing with rain and IFR/MVFR cigs
likely for most eastern terminals (KGEG-KCOE-KSFF-KCOE).
Steady rain has ended frm KMWH-KEAT but strengthening W flow will
continue to slop light showers across the Cascade crest and
across these terminals through early morning. The main cold front
with this system becomes draped across the region in a sw to ne
fashion on friday making very little progression toward the south
keeping plenty of mid and high level moisure streaming through the
region. In the lower-levels...low pressure deepens east of the
Divide incr sw pressure gradients yielding abundant upsloping
showers frm KCQV-KPUW and all points east. Additionally...strong
to gusty winds winds of 12-22kts with gusts 24-29kts are expected
through much of the aftn. Improving conditions and lighter winds
expected across the region aft 03z. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 43 61 43 65 44 75 / 90 50 20 10 0 10
Coeur d`Alene 43 61 42 65 41 75 / 100 60 20 10 10 10
Pullman 43 62 45 66 42 76 / 90 60 30 20 10 10
Lewiston 48 69 50 73 48 81 / 100 30 20 10 10 10
Colville 42 65 40 67 41 77 / 100 70 10 0 0 0
Sandpoint 42 61 40 62 39 72 / 100 90 20 10 10 10
Kellogg 41 58 42 63 42 73 / 100 90 50 20 10 10
Moses Lake 45 68 43 71 45 79 / 100 10 0 0 0 10
Wenatchee 46 67 45 69 48 76 / 70 10 0 0 0 10
Omak 42 68 35 69 41 77 / 70 10 0 0 0 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
334 AM CDT FRI APR 20 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
333 AM CDT FRI APR 20 2012
MAIN FORECAST CONCERNS ARE ON FROST/FREEZE TONIGHT AND NEXT EXPECTED
RAIN SATURDAY/SATURDAY NIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING BUILDING UP OVER THE WESTERN U.S....TROUGHING FROM
MINNESOTA SOUTH INTO TEXAS...AND RIDGING ALONG THE EAST COAST OF THE
U.S. WITHIN THE TROUGHING...MAIN FEATURES OF NOTE INCLUDE SHORTWAVES
OVER THE EASTERN SIDE OF THE FORECAST AREA AND BACK OVER WESTERN
SOUTH DAKOTA INTO NORTHWEST NEBRASKA. THE LATTER SHORTWAVE HAS
HELPED PUSH THE LOW TO MID LEVEL FRONTOGENESIS ZONE AND DEEP
MOISTURE SEEN ON THE 00Z GRB SOUNDING EASTWARD. REGARDING THAT
FRONTOGENESIS ZONE...THIS IS EASILY SEEN IN 00Z RAOBS AT 850MB WITH
0C AT MPX...3C AT GRB AND 12C AT DVN. IN ADDITION...AN UPPER JET
STREAK OF 100-110 KT IN EASTERN ONTARIO LAST EVENING...AIDING IN
FORCING FOR PRECIPITATION ACROSS WISCONSIN...HAS BEEN PUSHED
EASTWARD BY THE SHORTWAVE. LATEST RADAR MOSAIC SHOWS JUST A LITTLE
LIGHT RAIN/SNOW IN A WEAKENING COLD CONVEYOR BELT IN CENTRAL
WISCONSIN. TO THE WEST...SUBSIDENCE AND DRYING HAS BEEN CLEARING
SKIES OUT ACROSS MINNESOTA. A SURFACE RIDGE OF HIGH PRESSURE HAS
ALSO BEEN DROPPING SOUTH INTO THE DAKOTAS AND WESTERN MINNESOTA.
FARTHER WEST...A FEW SHOWERS CONTINUE BACK OVER CENTRAL SOUTH
DAKOTA AHEAD OF THE SHORTWAVE THERE. LAST ITEM OF NOTE IS A
SHORTWAVE ON WATER VAPOR COMING INTO SOUTHERN BRITISH COLUMBIA.
TODAY AND TONIGHT...UPPER TROUGHING OVER MINNESOTA WILL SLIDE EAST
ACROSS THE THE FORECAST AREA TODAY...ALLOWING THE SURFACE RIDGE OF
HIGH PRESSURE TO BUILD INTO THE FORECAST AREA THIS EVENING. THIS
SHOULD ALLOW FOR CLEARING AND DRYING. TEMPERATURES ARE LIKELY TO NOT
END UP MUCH HIGHER THAN YESTERDAY BECAUSE 850MB TEMPS ARE -2 TO
-3C...BUT MORE SUN AND THE LACK OF RAIN WILL MAKE IT FEEL WARMER.
QUESTION TONIGHT IS FROST/FREEZE. HAVING THE SURFACE RIDGE OVER
THE AREA IN THE EVENING IS GOOD FOR GETTING COLD...BUT THERE IS AN
ISSUE LURKING UPSTREAM. THE SHORTWAVE COMING INTO SOUTHERN BRITISH
COLUMBIA MODELS SHOW TOPPING THE WESTERN U.S. RIDGE TODAY...THEN
DROPPING INTO THE EASTERN DAKOTAS BY 12Z SATURDAY. ANTICIPATING A
STREAM OF MID AND HIGH LEVEL CLOUD COVER TO SPREAD DOWNSTREAM
AHEAD OF THIS SHORTWAVE...MOVING INTO THE FORECAST AREA AFTER
MIDNIGHT. IT APPEARS LOCATIONS ACROSS SOUTHWEST INTO CENTRAL
WISCONSIN WILL STAY THE CLEAREST THE LONGEST...AND THE SURFACE
RIDGE IS EXPECTED TO STAY IN PLACE THERE TOO. THEREFORE... FEEL
THIS AREA HAS THE BEST POTENTIAL FOR FREEZE CONDITIONS WITH
AREAS/WIDESPREAD FROST. FREEZE WARNINGS NOTED IN THE WWA SECTION
BELOW. ANOTHER POTENTIAL ISSUE TO CONTEND WITH MIGHT BE FOG GIVEN
RECENT RAINS. NOT VERY CONFIDENT TO INCLUDE FOG AT THIS TIME...
EITHER FOR RADIATIONAL INDUCED OR IN THE VALLEYS...AS THERE SHOULD
BE DECENT DRYING TODAY.
SATURDAY AND SATURDAY NIGHT...SHORTWAVE OVER THE EASTERN DAKOTAS
LOOKS TO CONTINUE ITS SOUTHEASTWARD TREK DOWN THE UPPER RIDGE. THE
20.00Z NAM IS AN OUTLIER WITH ITS TRACK...MOVING INTO WISCONSIN
TONIGHT. THE 20.00Z GFS/UKMET/ECMWF ALL TAKE A FARTHER WEST TRACK
THROUGH SOUTHEAST MINNESOTA AND NORTHEAST IOWA TONIGHT WHICH SEEMS
MORE REASONABLE. ISENTROPIC LIFT ASSOCIATED WITH THE SHORTWAVE...
BEST SEEN ON 290-300K SURFACES...WILL MOVE INTO SOUTHEAST MINNESOTA
AND NORTHEAST IOWA ON SATURDAY. SHOULD EVENTUALLY SEE RAIN DEVELOP
AS LOW LEVELS MOISTEN. AFTERNOON SEEMS MOST LIKELY TO SEE RAIN.
ANOTHER FAVORABLE FORCING MECHANISM IS A 120KT UPPER JET DROPPING
DOWN INTO SOUTHWEST MINNESOTA...PLACING LOCATIONS WEST OF THE
MISSISSIPPI RIVER IN UPPER DIVERGENCE. NICE LOW TO MID LEVEL
FRONTOGENESIS/FRONTOLYSIS COUPLET SHOWS UP TOO. BOTH THE ISENTROPIC
LIFT AND UPPER JET FORCING DIMINISHES SATURDAY NIGHT...WHICH WOULD
SUGGEST PRECIPITATION SHOULD DIMINISH. THE LOW TO MID LEVEL
FRONTOGENESIS LINGERS...THOUGH...NOTED TOO BY AN INVERTED TROUGH AT
THE SURFACE LINGERING BACK INTO WESTERN MINNESOTA. THEREFORE...
SHOULD STILL SEE SOME LIGHT PRECIPITATION AFTER MIDNIGHT. GIVEN THE
STRONG FORCING SIGNALS...HAVE RAISED PRECIPITATION CHANCES
UP...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. PRECIPITABLE WATER
VALUES ARE NOT THAT IMPRESSIVE...0.5-0.6 INCHES...WHICH MEANS WE
SHOULD NOT SEE MUCH QPF. ONLY CONCERN THAT EXISTS IS THE
PRECIPITATION COULD SHIFT WESTWARD OVER THE NEXT 24-48 HOURS SEEING
MODEL TRENDS. WITH PLENTY OF CLOUDS SPREADING IN SATURDAY MORNING
AND 850MB TEMPS OF 0 TO -2C ON SATURDAY...ANTICIPATING COOL
TEMPERATURES. ONLY 5 TO 10 DEGREES OF COOLING EXPECTED SATURDAY
NIGHT THANKS TO CLOUDS REMAINING IN PLACE.
SUNDAY AND SUNDAY NIGHT...20.00Z GFS/NAM/UKMET/ECMWF/CANADIAN ALL
SHOW ANOTHER SHORTWAVE DROPPING DOWN THE EAST SIDE OF THE WESTERN
U.S. RIDGE. AGAIN...THE MODELS DIFFER WITH THE TRACK...UKMET
FARTHEST WEST NEAR I-35 WITH THE NAM FARTHEST EAST OVER SOUTHWEST
WISCONSIN. IN ANY EVENT...THIS SHORTWAVE COMES THROUGH DURING THE
DAYTIME HOURS. WITH THAT INVERTED SURFACE TROUGH IN PLACE AND
DAYTIME HEATING...SHOULD SEE SOME ISOLATED/SCATTERED SHOWERS
DEVELOP. IF THERE IS ANYTHING GOING AGAINST PRECIPITATION IS A
NORTHEAST TO SOUTHWEST ORIENTED SURFACE RIDGE PROGGED TO BUILD INTO
THE AREA DURING THE AFTERNOON. A DRYING NORTHEAST FLOW COULD LIMIT
SOME OF THE AREAL COVERAGE OF PRECIPITATION...AS SUGGESTED IN 20.00Z
GFS OUTPUT. THEREFORE...FOR NOW CHANCES ARE ONLY 20-30. THE DRYING
FLOW PLUS DAYTIME MIXING SHOULD ALLOW FOR SOME DECREASE IN
CLOUDS...THOUGH A BETTER SHOT OF CLEARING SHOULD COME SUNDAY NIGHT
WITH SUBSIDENCE IN THE WAKE OF THE SHORTWAVE. REGARDING
TEMPERATURES...850MB READINGS ON SUNDAY ARE SIMILAR TO SATURDAY...0
TO -2C. WITH OVERALL LIMITED SUN...ANTICIPATE ANOTHER RELATIVELY
COOL DAY WITH HIGHS IN THE 50S. IF MORE SUN OCCURS THAN
EXPECTED...READINGS MAY GET INTO THE 60S. WITH CLEARING SUNDAY NIGHT
AND THE RIDGE SETTLING IN...COULD SEE YET ANOTHER FROST/FREEZE
NIGHT...ESPECIALLY FOR SOUTHWEST AND CENTRAL WISCONSIN.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
333 AM CDT FRI APR 20 2012
DIFFICULT LONG TERM FORECAST...ESPECIALLY GETTING INTO THE MIDDLE OF
NEXT WEEK WHERE MODELS ARE ALL OVER THE PLACE WITH THE HANDLING OF
THE UPPER LEVEL PATTERN OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THROUGH ABOUT TUESDAY...MODELS ARE IN GOOD AGREEMENT
MAINTAINING WESTERN RIDGING AND TROUGHING OVER THE EAST COAST OF THE
U.S.. 500MB HEIGHTS DO RISE MONDAY THROUGH TUESDAY WHICH WILL HELP
TO BRING WARMER AIR INTO THE FORECAST AREA. BY 00Z WEDNESDAY...850MB
TEMPS CLIMB TO 4-8C...IF NOT A LITTLE HIGHER. STILL HAVING TO
MAINTAIN SOME CHANCES OF PRECIPITATION TUESDAY NIGHT...DUE TO A
SHORTWAVE PROGGED TO COME THROUGH THE NORTHWEST FLOW. 20.00Z
ECMWF/GEM ARE PRETTY ACTIVE WITH THIS SHORTWAVE TOO...RESULTING FROM
FAVORABLE DYNAMICAL FORCING. WHAT HAPPENS IN THE WAKE OF THIS
FEATURE IS ANYONES GUESS RIGHT NOW. THE 20.00Z ECMWF IS STUCK WITH
TROUGHING FROM HUDSON BAY DOWN INTO THE EASTERN GREAT LAKES...
MAINTAIN A COOL NORTHWEST FLOW. WOULD PROBABLY END UP WITH
PERIODIC RAIN SHOWERS WITH SHORTWAVES MOVING THROUGH IN THE ECMWF
SCENARIO. ON THE OTHER HAND...THE 20.00Z GFS/GFS ENSEMBLES SAY
WEDNESDAY THROUGH THURSDAY THE WESTERN RIDGE TRIES TO BUILD
TOWARDS THE AREA...BEING PUSHED MORE BY TROUGHING COMING INTO THE
WEST COAST. IF THIS HAPPENS...PERIODIC SHOWER AND THUNDERSTORMS
CHANCES WOULD RESULT AS A WARM FRONT APPROACHES THE REGION. THE
SOLUTIONS ALSO ARE MUCH WARMER THAN THE ECMWF. FOR NOW...HAVE
SPLIT THE DIFFERENCE BETWEEN THE TWO SOLUTIONS. NEEDLESS TO
SAY...CONFIDENCE ON THE PRECIPITATION AND TEMPERATURE FORECASTS IS
LOW.
&&
.AVIATION...
1100 PM CDT THU APR 19 2012
THE MAIN AREA OF RAIN WAS ALREADY EAST OF KRST AND WILL BE EAST OF
KLSE BEFORE 06Z. SOME LIGHT RAIN HAS DEVELOPED ON THE BACKSIDE OF
THIS LARGER RAIN SHIELD THOUGH...BUT VSBYS HAVE TRENDED TOWARD P6SM.
KRST/KLSE WILL HAVE TO DEAL WITH THIS THROUGH ABOUT 09-10Z.
LOW CIGS SHOULD GIVE WAY TO VFR CONDITIONS BETWEEN 14-16Z...WITH
THESE CONDITIONS PERSISTING THROUGH FRIDAY NIGHT. WINDS WILL STAY UP
THROUGH THE OVERNIGHT AS THE TIGHT PRESSURE GRADIENT WITH THE
EXITING LOW PRESSURE SYSTEM REMAINS. EVENTUAL SUNSHINE ON FRIDAY
WILL PROMOTE MIXING AND LIKELY SOME GUSTINESS FROM LATE MORNING
THROUGH THE AFTERNOON. LOOK FOR LIGHTER WINDS FRIDAY NIGHT WITH
DECOUPLING AND AN AREA OF HIGH PRESSURE BUILDING IN FROM THE WEST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
333 AM CDT FRI APR 20 2012
WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR WIZ017-029-034-
042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1132 AM EDT FRI APR 20 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE ACROSS THE AREA EARLY TODAY WILL LOSE
ITS INFLUENCE OVER THE WEATHER TONIGHT. A LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE GREAT LAKES TONIGHT AND THEN INTO NEW ENGLAND
SATURDAY. AN ATTACHED COLD FRONT WILL CROSS THE AREA SATURDAY. LOW
PRESSURE WILL DEEPEN NEAR FLORIDA SUNDAY AND THEN STRENGTHEN WHILE
MOVING NORTHWARD ALONG THE FRONT THROUGH MONDAY. THE STRONG LOW WILL
THEN TRACK NORTH OF THE AREA MONDAY THROUGH TUESDAY. HIGH PRESSURE
WILL EVENTUALLY BUILD BACK ACROSS THE AREA BY THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE STRATUS IS NOW GONE...AND THE FORECAST PROBLEM IS NOW BASED
ALMOST ENTIRELY ON THE CUMULUS/STRATOCUMULUS DECK COVERING MUCH
OF THE FORECAST AREA LATE THIS MORNING. THE LATEST RUC SUGGESTS
THAT THE AREA OF CLOUDINESS ACROSS SOUTHEAST PORTIONS CONSOLIDATES
EARLY THIS AFTERNOON...THEN MOVES NORTHEAST WITH THE BOUNDARY
LAYER FLOW.
THERE IS A BREAK DEVELOPING ACROSS THE SOUTHERN DELMARVA...BUT
THIS MAY NOT HAVE MUCH OF AN IMPACT ON THE SKY COVER ACROSS
EASTERN SECTIONS THIS AFTERNOON. BASED ON THE CLOUD COVER IN
PLACE...AND THE POTENTIAL FOR BREAKS THIS AFTERNOON...HIGH
TEMPERATURES WERE NUDGED DOWN ACROSS EASTERN SECTIONS. LESS
HEATING MAY MEAN LESS IN THE WAY OF SEA AND BAY BREEZES...AND
WINDS WERE ADJUSTED DOWN A BIT.
FURTHER WEST...THE CUMULUS IS MORE OR LESS BASED ON HEATING OF THE
MOISTENED BOUNDARY LAYER. THIS SHOULD MEAN MORE IN THE WAY OF
BREAK FOR SOUTHEAST PENNSYLVANIA THIS AFTERNOON...AND NOT AS MUCH
OF AN IMPACT FOR THE LEHIGH VALLEY AND THE HIGHER TERRAIN. IN
THESE AREAS...HIGH TEMPERATURES WERE NOT MODIFIED MUCH BASED ON
THE EXPECTED SUNSHINE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
HERE WE WILL DEVIATE A BIT FROM THE WRF-NMMB AND TAKE AN AVERAGE OF
IT AND THE GFS. THE MOIST SERLY FLOW IS FORECAST TO PERSIST. AS SUCH
THE UPSLOPE, CONVERGENT FLOW SHOULD HELP DEVELOP CLOUDS. WE MIGHT BE
TOO FAST, BUT BELIEVE WE WILL GET THERE BEFORE THE NIGHT IS DONE.
BASED ON THE MODELS FORECASTING SOME LIGHT MEASURABLE, TOOK THIS AS
SOME UPSLOPING DRIZZLE OR LIGHT RAIN OCCURRING. WE KEPT A CHANCE IN
THE NORTHERN HALF OF OUR CWA. DO NOT THINK STAT GUIDANCE COULD GET
ANY CLOSER AND OTHER THAN PHL WHERE WE WENT ABOVE THEM BECAUSE OF
URBAN EFFECTS, PRETTY MUCH ACCEPTED IT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
CLOUDS WILL BE INCREASING ACROSS THE AREA SATURDAY AS LOW PRESSURE
WILL BE TRACKING DOWN THE SAINT LAWRENCE VALLEY AND ITS ATTACHED
COLD FRONT WILL BE APPROACHING FROM THE WEST. SHOWERS AND SCATTERED
TSTMS WILL ACCOMPANY THE FRONT. THE NAM AND GFS ARE BOTH INDICATING
SOME SFC BASED CAPE IN THE 500 TO 1000 J/KG RANGE FOR SATURDAY...SO
WE WILL KEEP THE THUNDER IN THERE FOR NOW. SPC HAS A `SEE TEXT`
MENTION IN THE SWODY2 DISCUSSION FOR THE NORTHERN MIDDLE ATLANTIC
REGION. THE FRONT SLOWS AS IT MOVES EAST OF THE AREA SATURDAY NIGHT.
THIS WILL PROLONG THE PRECIP EVENT WITH LIGHTER AMOUNTS SAT NIGHT
AND HIGH CHC POPS.
THE MORE SIGNIFICANT EVENT IN THE EXTENDED WILL ARRIVE SUNDAY IN THE
FORM OF DEEP MOISTURE AND LIFT ASSOCIATED WITH THE STRENGTHENING LOW
MOVING NORTHWARD FROM FL. THE SHIELD OF RAIN WILL OVERSPREAD THE
AREA FROM THE SOUTH SUN MORNING AND PERSIST OVER THE AREA AT LEAST
UNTIL MON MORNING WITH THE POTENTIAL OF 1 TO 3 INCHES OF RAIN. THE
MODELS HAVE COME INTO BETTER AGREEMENT (COMPARED TO YESTERDAY) BUT
ARE STILL OFFERING DIFFERENT TRACK AFTER THEY ARRIVE AT OUR
LATITUDE. THE GFS TURNED THE DEEP SFC LOW MORE WESTWARD ACROSS PA
WHILE THE NAM AND 12Z EC TRACK THE SYSTEM NORTHWARD ACROSS THE
NEARSHORE WATERS. THE 12Z EC HOOKS THE LOW BACK WESTWARD ONCE IT
REACHES NYC HOWEVER. THE OVERNIGHT EXTENDED GRIDS HAVE BEEN MODIFIED
TO RESEMBLE THE NAM/12Z EC SOLUTIONS FOR THE MOST PART...NOT MUCH
DIFFERENT THE THE PREVIOUS FCST. HIGHER POPS AND NEW HPC QPF
GRAPHICS HAVE BEEN CREATED.
THE DEEP LOW WILL TRACK AWAY FROM THE AREA MON-WED. HIGH PRESSURE
WILL GRADUALLY BUILD BACK ACROSS THE AREA. WINDY AND COOL WEATHER
WILL BE ACROSS THE AREA MON-WED. POPS DECREASE BACK TO CHC LEVELS BY
MON AFTERNOON...THEN SLGT CHC FOR MON NIGHT AND TUE. TEMPERATURES
MAY BE LOW ENOUGH TO SUPPORT SOME SNOW ACROSS THE FAR NORTH...BUT IT
WILL BE VERY MARGINAL AND IT MAY BE A LOW ENOUGH PROBABILITY EVENT
TO NOT INCLUDE IN THE FCST ATTM.
WE ARE KEEPING A DRY FCST AT THE END OF THE EXTENDED PERIOD FOR NOW.
THE NEW EC HAS ARRIVED HOWEVER WITH ANOTHER SYNOPTIC SYSTEM ACROSS
THE AREA...WE`LL HAVE TO WATCH THIS FOR A FEW MORE MODEL RUNS TO SEE
IF HIGHER POPS WILL BE NEEDED.
&&
.AVIATION /16Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE STRATUS/FOG CONTINUE TO ERODE...WITH THE IFR CONDITIONS EXPECTED
TO BE GONE BY 1430 UTC. THE NEXT PROBLEM IS THE CLOUDINESS EXTENDING
NORTHWEST FROM THE ATLANTIC INTO DELAWARE...NEW JERSEY AND SOUTHEAST
PENNSYLVANIA. FOR THE MOST PART...THE CEILINGS ARE VFR...BUT THERE
IS A BATCH OF MVFR CEILINGS EXTENDING FROM SOUTHERN DELAWARE INTO
SOUTHERN NEW JERSEY (KMIV) AND SOUTHEAST PENNSYLVANIA (NEAR KPHL).
WITH HEATING...THE CLOUD BASE SHOULD RISE...AND VFR CEILINGS ARE
EXPECTED THIS AFTERNOON. HOWEVER...MVFR CEILINGS COULD AFFECT
KMIV...KILG...KPHL AND POSSIBLY KPNE THROUGH ABOUT 1600 UTC. AFTER
THAT TIME...ALL CEILINGS ARE EXPECTED TO BE VFR.
WINDS ARE TRYING TO COME AROUND TO SEA AND BAY BREEZE CONFIGURATION...
AND FOR THE MOST PART WINDS ARE EXPECTED TO REMAIN BELOW 10
KNOTS.
FOR TONIGHT WE ARE FOLLOWING THE SUGGESTION OF ONE MODEL THAT A
MVFR CIG SHOULD DEVELOP AND OR MOVE IN FROM THE OCEAN AND BAY
DURING THE EVENING HOURS. CONFIDENCE ON THE EVOLUTION IS GREATER
THAN AVERAGE ALTHOUGH THE SPECIFIC TIMING OF OCCURRENCE WE ARE
LESS CONFIDENT. SOME VSBY RESTRICTIONS DUE TO FOG ARE ALSO
POSSIBLE. WINDS WILL REMAIN FROM THE SOUTHEAST, BUT BECOME
LIGHTER.
OUTLOOK...
SAT AND SAT NIGHT...DETERIORATING CONDITIONS EXPECTED SATURDAY WITH
PERIODS OF MVFR/IFR IN SHOWERS AND SCT TSTMS. CONDITIONS MOSTLY
SUB-VFR SAT NIGHT WITH LOW CIGS/VSBYS.
SUN-MON...MOSTLY IFR CONDITIONS WITH LOW CIGS/VSBYS RAIN AND
GUSTY WINDS.
MON NGT-TUE...IMPROVEMENT TO VFR BY TUE ACROSS MOST AREAS BUT SCT SHOWERS
MAY CREATE LOWER CONDITIONS AT TIMES.
&&
.MARINE...
SUB SMALL CRAFT ADVISORY CONDITIONS ARE FORECAST TO CONTINUE TODAY
AND TONIGHT. WAVE WATCH GUIDANCE CONTINUES TO BE TOO HIGH WITH THE
EASTERLY SWELL AND WE ARE TAKING APPROXIMATELY A FOOT OFF THE
GUIDANCE. WINDS OVERALL TODAY SHOULD BE RELATIVELY LIGHT FROM THE
EAST AND SOUTHEAST. THERE WILL LIKELY BE AN INCREASE IN SPEED IN
DELAWARE BAY AGAIN LATER IN THE AFTERNOON AND EARLY IN THE EVENING
AS THE FLOW WILL BE UP THE BAY AGAIN.
WINDS SHOULD BACK MORE TO THE SOUTH TONIGHT, BUT OVERALL SPEEDS
SHOULD REMAIN LESS THAN 15KTS. SWELLS ARE NOT EXPECTED TO INCREASE
IN TIME TO CAUSE ANY SMALL CRAFT CONDITIONS.
OUTLOOK...
SMALL CRAFT CONDITIONS DEVELOPING SAT WITH GALES POSSIBLE SUN-MON.
A RETURN BACK TO SUB-SCA CONDITIONS BY TUE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...GIGI/HAYES
SHORT TERM...GIGI
LONG TERM...O`HARA
AVIATION...GIGI/HAYES
MARINE...GIGI
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
835 AM EDT FRI APR 20 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE ACROSS THE AREA EARLY TODAY WILL LOSE
ITS INFLUENCE OVER THE WEATHER TONIGHT. A LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE GREAT LAKES TONIGHT AND THEN INTO NEW ENGLAND
SATURDAY. AN ATTACHED COLD FRONT WILL CROSS THE AREA SATURDAY. LOW
PRESSURE WILL DEEPEN NEAR FLORIDA SUNDAY AND THEN STRENGTHEN WHILE
MOVING NORTHWARD ALONG THE FRONT THROUGH MONDAY. THE STRONG LOW WILL
THEN TRACK NORTH OF THE AREA MONDAY THROUGH TUESDAY. HIGH PRESSURE
WILL EVENTUALLY BUILD BACK ACROSS THE AREA BY THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE STRATUS/PATCHY DENSE FOG IS SLOWLY LIFTING ACROSS THE I-95
CORRIDOR...AS THE SUN ANGLE IS GETTING HIGH ENOUGH TO ALLOW THE
MOISTURE TO MIX OUT FROM UNDER THE INVERSION. THIS AREA SHOULD BE
GONE BEFORE 1000 AM...BASED ON CURRENT TRENDS.
THE NEXT PROBLEM IS THE CLOUDINESS EXTENDING NORTHWEST FROM THE
OCEAN. THE MASS IS NOW COVERING MUCH OF DELAWARE AND MUCH OF
SOUTHEAST NEW JERSEY. EVEN THOUGH THE CLOUDINESS IS NOT AS LOW AS
THE STRATUS IN PLACE NOW...IT WILL AFFECT THE CLOUD COVER
FORECAST...AS WELL AS THE TEMPERATURE FORECAST...FOR THE REST OF
THE MORNING AT LEAST.
THE LATEST RUC SUGGESTS THAT THE AREA OF CLOUDINESS ACROSS
SOUTHEAST PORTIONS CONSOLIDATES LATER THIS MORNING...THEN MOVES
NORTHEAST WITH THE BOUNDARY LAYER FLOW. THIS WOULD ALLOW SOME
IMPROVEMENT FOR DELAWARE AND SOUTHEAST NEW JERSEY THIS AFTERNOON.
BASED ON TRENDS...WILL NUDGE THE CLOUD FORECAST IN THIS DIRECTION.
STAT GUIDANCE IS AMAZINGLY UNIFORM AND A BLEND WAS USED. WE UPPED
MAXES THEN SLIGHTLY INLAND BECAUSE OF RECENT TRENDS AND OUR DRY
WEATHER. TRIED AGAIN TO SHOW AN EARLIER IN THE DAY MAX TEMP ALONG
THE COAST. DO NOT KNOW IF WE WILL SEE A SEA BREEZE FRONT PER SE ON
OUR RADARS TODAY, BUT THE GENERAL WIND FLOW WILL BE SOUTHEAST.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
HERE WE WILL DEVIATE A BIT FROM THE WRF-NMMB AND TAKE AN AVERAGE OF
IT AND THE GFS. THE MOIST SERLY FLOW IS FORECAST TO PERSIST. AS SUCH
THE UPSLOPE, CONVERGENT FLOW SHOULD HELP DEVELOP CLOUDS. WE MIGHT BE
TOO FAST, BUT BELIEVE WE WILL GET THERE BEFORE THE NIGHT IS DONE.
BASED ON THE MODELS FORECASTING SOME LIGHT MEASURABLE, TOOK THIS AS
SOME UPSLOPING DRIZZLE OR LIGHT RAIN OCCURRING. WE KEPT A CHANCE IN
THE NORTHERN HALF OF OUR CWA. DO NOT THINK STAT GUIDANCE COULD GET
ANY CLOSER AND OTHER THAN PHL WHERE WE WENT ABOVE THEM BECAUSE OF
URBAN EFFECTS, PRETTY MUCH ACCEPTED IT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
CLOUDS WILL BE INCREASING ACROSS THE AREA SATURDAY AS LOW PRESSURE
WILL BE TRACKING DOWN THE SAINT LAWRENCE VALLEY AND ITS ATTACHED
COLD FRONT WILL BE APPROACHING FROM THE WEST. SHOWERS AND SCATTERED
TSTMS WILL ACCOMPANY THE FRONT. THE NAM AND GFS ARE BOTH INDICATING
SOME SFC BASED CAPE IN THE 500 TO 1000 J/KG RANGE FOR SATURDAY...SO
WE WILL KEEP THE THUNDER IN THERE FOR NOW. SPC HAS A `SEE TEXT`
MENTION IN THE SWODY2 DISCUSSION FOR THE NORTHERN MIDDLE ATLANTIC
REGION. THE FRONT SLOWS AS IT MOVES EAST OF THE AREA SATURDAY NIGHT.
THIS WILL PROLONG THE PRECIP EVENT WITH LIGHTER AMOUNTS SAT NIGHT
AND HIGH CHC POPS.
THE MORE SIGNIFICANT EVENT IN THE EXTENDED WILL ARRIVE SUNDAY IN THE
FORM OF DEEP MOISTURE AND LIFT ASSOCIATED WITH THE STRENGTHENING LOW
MOVING NORTHWARD FROM FL. THE SHIELD OF RAIN WILL OVERSPREAD THE
AREA FROM THE SOUTH SUN MORNING AND PERSIST OVER THE AREA AT LEAST
UNTIL MON MORNING WITH THE POTENTIAL OF 1 TO 3 INCHES OF RAIN. THE
MODELS HAVE COME INTO BETTER AGREEMENT (COMPARED TO YESTERDAY) BUT
ARE STILL OFFERING DIFFERENT TRACK AFTER THEY ARRIVE AT OUR
LATITUDE. THE GFS TURNED THE DEEP SFC LOW MORE WESTWARD ACROSS PA
WHILE THE NAM AND 12Z EC TRACK THE SYSTEM NORTHWARD ACROSS THE
NEARSHORE WATERS. THE 12Z EC HOOKS THE LOW BACK WESTWARD ONCE IT
REACHES NYC HOWEVER. THE OVERNIGHT EXTENDED GRIDS HAVE BEEN MODIFIED
TO RESEMBLE THE NAM/12Z EC SOLUTIONS FOR THE MOST PART...NOT MUCH
DIFFERENT THE THE PREVIOUS FCST. HIGHER POPS AND NEW HPC QPF
GRAPHICS HAVE BEEN CREATED.
THE DEEP LOW WILL TRACK AWAY FROM THE AREA MON-WED. HIGH PRESSURE
WILL GRADUALLY BUILD BACK ACROSS THE AREA. WINDY AND COOL WEATHER
WILL BE ACROSS THE AREA MON-WED. POPS DECREASE BACK TO CHC LEVELS BY
MON AFTERNOON...THEN SLGT CHC FOR MON NIGHT AND TUE. TEMPERATURES
MAY BE LOW ENOUGH TO SUPPORT SOME SNOW ACROSS THE FAR NORTH...BUT IT
WILL BE VERY MARGINAL AND IT MAY BE A LOW ENOUGH PROBABILITY EVENT
TO NOT INCLUDE IN THE FCST ATTM.
WE ARE KEEPING A DRY FCST AT THE END OF THE EXTENDED PERIOD FOR NOW.
THE NEW EC HAS ARRIVED HOWEVER WITH ANOTHER SYNOPTIC SYSTEM ACROSS
THE AREA...WE`LL HAVE TO WATCH THIS FOR A FEW MORE MODEL RUNS TO SEE
IF HIGHER POPS WILL BE NEEDED.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
WITH THE 06Z TAFS NOT VERY CONFIDENT ABOUT THE VSBY RESTRICTIONS
THIS MORNING. THAT PART RANG TRUE. EXPECT GENERALLY VFR
CONDITIONS LATER THIS MORNING AND AFTERNOON WITH CIGS AND VSBYS
LOWERING TONIGHT INTO MVFR LEVELS IF NOT LOWER.
THROUGH THIS MORNING MADE SOME ADJUSTMENTS BASED ON TEMP AND DEW
POINT SPREADS AND WENT MORE OPTIM WITH THE FOG NORTHWEST OF KPHL
AREA AIRPORTS AND MORE PESIM AT KMIV AND NOW KACY BECAUSE THEY
RADIATED. CLOUDS SWIRLING OFFSHORE ARE NOT MAKING ANY MOVEMENT
TOWARD THE COAST, WILL CONTINUE TO MONITOR FOR A CHANGE. THERE ARE
SOME BORDERLINE IFR STRATUS CLOUDS FORMING OFF OF DELAWARE BAY AND
WILL AFFECT KPHL EARLY. WINDS WILL BE LIGHT.
THE EXCELLENT RADIATIONAL COOLING CONDITIONS HAVE MADE IT EASY FOR
FOG TO FORM AND WE HAVE AMENDED MOST OF THE AIRPORTS DOWNWARD.
UNFORTUNATELY KPHL PROXIMITY TO THE DELAWARE RIVER HAS BROUGHT SOME
OF THE DENSEST FOG ALONG THE DELAWARE TO THE AIRPORT. STILL NOT
MANY CLOUDS ABOVE THE FOG AND STRATUS AND WE ARE STILL EXPECTING A
FAST IMPROVEMENT LATER THIS MORNING BY 13Z OR 14Z.
DURING THE DAY TODAY WE ARE EXPECTING ANY LOW CLOUDS AND VSBY
RESTRICTIONS TO BE GONE QUICKLY. A NON CIG CUMULUS DECK IS FORECAST
TO DEVELOP. LEAST CONFIDENCE ABOUT THE LACK OF A CIG SERN TERMINALS.
NOT SURE IF THERE WILL BE A DISCERNIBLE SEA BREEZE, BUT THE OVERALL
GRADIENT WINDS SHOULD BE SOUTHEAST TO SOUTH WITH SPEEDS AROUND 10
KTS.
FOR TONIGHT WE ARE FOLLOWING THE SUGGESTION OF ONE MODEL THAT A
MVFR CIG SHOULD DEVELOP AND OR MOVE IN FROM THE OCEAN AND BAY
DURING THE EVENING HOURS. CONFIDENCE ON THE EVOLUTION IS GREATER
THAN AVERAGE ALTHOUGH THE SPECIFIC TIMING OF OCCURRENCE WE ARE
LESS CONFIDENT. SOME VSBY RESTRICTIONS DUE TO FOG ARE ALSO
POSSIBLE. WINDS WILL REMAIN FROM THE SOUTHEAST, BUT BECOME
LIGHTER.
OUTLOOK...
SAT AND SAT NIGHT...DETERIORATING CONDITIONS EXPECTED SATURDAY WITH
PERIODS OF MVFR/IFR IN SHOWERS AND SCT TSTMS. CONDITIONS MOSTLY
SUB-VFR SAT NIGHT WITH LOW CIGS/VSBYS.
SUN-MON...MOSTLY IFR CONDITIONS WITH LOW CIGS/VSBYS RAIN AND
GUSTY WINDS.
MON NGT-TUE...IMPROVEMENT TO VFR BY TUE ACROSS MOST AREAS BUT SCT SHOWERS
MAY CREATE LOWER CONDITIONS AT TIMES.
&&
.MARINE...
SUB SMALL CRAFT ADVISORY CONDITIONS ARE FORECAST TO CONTINUE TODAY
AND TONIGHT. WAVE WATCH GUIDANCE CONTINUES TO BE TOO HIGH WITH THE
EASTERLY SWELL AND WE ARE TAKING APPROXIMATELY A FOOT OFF THE
GUIDANCE. WINDS OVERALL TODAY SHOULD BE RELATIVELY LIGHT FROM THE
EAST AND SOUTHEAST. THERE WILL LIKELY BE AN INCREASE IN SPEED IN
DELAWARE BAY AGAIN LATER IN THE AFTERNOON AND EARLY IN THE EVENING
AS THE FLOW WILL BE UP THE BAY AGAIN.
WINDS SHOULD BACK MORE TO THE SOUTH TONIGHT, BUT OVERALL SPEEDS
SHOULD REMAIN LESS THAN 15KTS. SWELLS ARE NOT EXPECTED TO INCREASE
IN TIME TO CAUSE ANY SMALL CRAFT CONDITIONS.
OUTLOOK...
SMALL CRAFT CONDITIONS DEVELOPING SAT WITH GALES POSSIBLE SUN-MON.
A RETURN BACK TO SUB-SCA CONDITIONS BY TUE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...GIGI/HAYES
SHORT TERM...GIGI
LONG TERM...O`HARA
AVIATION...GIGI
MARINE...GIGI
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
707 AM EDT FRI APR 20 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL LINGER ACROSS THE REGION TODAY. A STRONG
LOW PRESSURE SYSTEM WILL THEN TRACK OVER THE AREA OR JUST OFFSHORE
SATURDAY NIGHT INTO SUNDAY FOLLOWED BY A COOLER AND DRIER HIGH
PRESSURE SYSTEM THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MINOR CHANGES WERE MADE TO THE GRIDDED AND TEXT FORECASTS
WITH THE UPDATE THAT WAS JUST ISSUED.
A PRONOUNCED WEDGING PATTERN REMAINS IN PLACE ACROSS SOUTHEAST
SOUTH CAROLINA AND SOUTHEAST GEORGIA EARLY THIS MORNING. SURFACE
PRESSURES ARE BEGINNING TO FALL WITHIN THE CORE OF THE IN-SITU
WEDGE HIGH PER 20/11Z ISALLOBARIC ANALYSIS WHICH SUGGESTS THE
WEDGE CORE IS SHOWING THE INITIAL SIGNS OF BREAKING DOWN.
WIDESPREAD LOW CLOUDS DOMINATE MUCH OF THE REGION WITH CEILING
HOVERING BETWEEN 500-800 FT AT MOST OBSERVATION SITES.
AS IS TYPICALLY THE CASE IN COLD AIR DAMMING SITUATIONS...THE
MODELS ARE STRUGGLING WITH HOW QUICKLY THE WEDGE WILL ERODE TODAY.
WITH SURFACE PRESSURES ALREADY FALLING ACROSS THE CAROLINA
PIEDMONT...IT WOULD APPEAR CONDITIONS WILL FAVOR A FAIRLY
PROGRESSIVE EROSION THIS MORNING...ESPECIALLY IN THE ABSENCE OF
LIGHT RAIN INDUCING DIABATIC EFFECTS. CLOUDS WILL GRADUALLY SCOUR
OUT AS THE WEDGE BREAKS DOWN AND THE MID-LEVEL SYNOPTIC FLOW
VEERS TO THE SOUTHWEST...BUT FORECAST SOUNDINGS SUGGEST LOW CLOUDS
WILL LIKELY BE REPLACED WITH A FAIRLY HEALTHY CUMULUS FIELD WITH
DEWPOINTS HOLDING IN THE 60S. WILL HIGHLIGHT CLOUDY SKIES BECOMING
PARTLY CLOUDY BY AFTERNOON ALL AREAS WITH HIGHS RANGING FROM THE
UPPER 70S NORTH TO THE LOWER 80S SOUTH. ISOLATED SHOWERS WILL BE
POSSIBLE JUST ABOUT ANYWHERE TODAY WITH ACTIVITY GENERALLY
REMAINING CONFINED AHEAD OF THE SEA BREEZE THIS AFTERNOON. WILL
MAINTAIN SLIGHT CHANCE POPS AWAY FROM THE COASTAL AREAS TODAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
ANY LINGERING SHOWER/TSTM ACTIVITY WILL QUICKLY DISSIPATE AFTER
SUNSET WITH THE LOSS OF INSOLATION. CUMULUS SHOULD ALSO QUICKLY
DIMINISH AS SURFACE HEATING CEASES. IT REMAINS TO BE SEEN HOW MUCH
STRATUS WILL REDEVELOP OVERNIGHT WITHIN THE STRENGTHENING
SOUTHWEST FLOW AHEAD OF AN APPROACHING COLD FRONT. NEITHER THE GFS
OR NAM MOS PACKAGES ARE EAGER ON LOW CLOUDS DEVELOPMENT TONIGHT...
BUT WITH STILL QUITE A BIT OF MOISTURE FORECAST TO LINGER
UNDERNEATH THE NOCTURNAL INVERSION THE POTENTIAL FOR LOW CLOUDS CAN
NOT BE COMPLETELY RULED OUT. WILL FORECAST MOSTLY CLEAR AND PARTLY
CLOUDY SKIES FOR NOW WITH LOWS IN THE LOWER-MID 60S.
THE WEATHER PATTERN WILL BECOME MUCH MORE ACTIVE ACROSS THE
EASTERN UNITED STATES BY THE WEEKEND. A SOUTHERN STREAM UPPER LOW
WILL SWEEP ACROSS THE GULF OF MEXICO ON SATURDAY...AS AN ASSOCIATED
SURFACE SYSTEM DEVELOPS OFF THE GULF COAST OF FLORIDA. THE FORECAST
AREA WILL BECOME LOCATED BETWEEN TWO AREAS OF DEEP MOISTURE ON
SATURDAY. ONE SWATH WILL BE SPREADING NORTHWARD ALONG THE SOUTHEAST
AND MID ATLANTIC COASTLINE...WHILE ANOTHER APPROACHES FROM THE
WEST COINCIDENT WITH THE NARROW LONGWAVE TROUGH AXIS. THERE ARE
SOME INDICATIONS IN NUMERICAL MODEL SOLUTIONS THAT THE REGION WILL
FALL WITHIN A BRIEF DRY SLOT ON SATURDAY...SOMEWHAT LIMITING RAIN
COVERAGE UNTIL BOTH THE SURFACE AND UPPER LEVEL SYSTEM SHIFT
ACROSS FLORIDA AND UP THE SOUTHEAST COASTLINE EARLY SUNDAY.
CONSIDERING THAT THE SURFACE AND UPPER LEVEL LOW ARE EXPECTED TO
TRACK TO THE SOUTH AND THEN OFF THE COAST OF THE FORECAST
AREA...WILL INDICATE THE BEST POTENTIAL FOR RAIN OVER THE WATERS
AND ADJACENT COASTAL COUNTIES INTO SATURDAY EVENING. ONCE THE
SURFACE LOW SHIFTS TOWARD THE SOUTH CAROLINA AND NORTH CAROLINA
COASTLINES ON SUNDAY...WRAP AROUND MOISTURE BEHIND THE LOW CENTER
WILL ALLOW PRECIPITATION TO SPREAD FARTHER INTO THE INLAND SOUTH
CAROLINA ZONES. AN EXAMINATION OF INSTABILITY PARAMETERS AND WIND
FIELDS SUGGESTS THAT MOST OF THE ORGANIZED SEVERE POTENTIAL WILL
BE CONFINED SOUTH OF THE FORECAST AREA OVER THE WEEKEND...AS
WOULD BE EXPECTED WITH THE MORE SOUTHERN TRACK OF THIS SYSTEM.
HAVE THUS LIMITED MENTION OF THUNDER TO SLIGHT CHANCE SATURDAY AND
SUNDAY.
AS THE CLOSED UPPER LOW LIFTS TOWARD THE SOUTHEAST COASTLINE ON
SUNDAY...IT EVENTUALLY BECOMES ABSORBED INTO A LARGER UPPER TROUGH
MOVING SOUTHWARD FROM CENTRAL CANADA SUNDAY NIGHT. THE SURFACE LOW
SYSTEM WILL RAPIDLY MOVE UP THE EAST COAST AND OUT OF THE AREA BY
MONDAY MORNING. HAVE INDICATED DECREASING RAIN CHANCES THROUGH THE
DAY SUNDAY...WITH POPS BELOW 15 PERCENT BY MONDAY MORNING.
LOWERING HEIGHTS AND FAIRLY IMPRESSIVE COLD ADVECTION FOR THIS
TIME OF YEAR IS EXPECTED EARLY NEXT WEEK BEHIND THE COASTAL SYSTEM.
WHILE HIGH TEMPERATURES WILL BE ABOVE AVERAGE ON SATURDAY...REACHING
THE LOWER 80S INLAND...HIGH TEMPERATURES WILL BE SUPPRESSED AROUND
70 DEGREES FOLLOWING THE SYSTEM SUNDAY AND MONDAY.
&&
.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
A BROAD UPPER TROUGH WILL LINGER ACROSS THE EASTERN UNITED STATES
THROUGH TUESDAY...SUPPORTING COOLER HIGH TEMPERATURES IN THE LOWER
70S. ONCE THE TROUGH AXIS SHIFTS OFF THE COAST MID WEEK...UPPER
RIDGING WILL BEGIN TO BUILD EASTWARD. THIS WILL ALLOW FOR A
WARMING TREND THROUGH THE END OF THE WEEK...WITH HIGH TEMPERATURES
RETURNING TO THE LOWER 80S BY THURSDAY AND FRIDAY. THERE IS SOME
MODEL DISAGREEMENT REGARDING A POTENTIAL WEAK BACKDOOR FRONT
SLIPPING INTO THE REGION THURSDAY AND FRIDAY. PREFER TO KEEP RAIN
CHANCES BELOW 15 PERCENT THROUGH THE EXTENDED FORECAST PERIOD
UNTIL MODEL CONSISTENCY REGARDING THIS SCENARIO IMPROVES.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
INCOMING GUIDANCE AND RUC SOUNDINGS SUGGEST IFR CIGS WILL QUICKLY
BREAK BY 15-16Z THIS MORNING AS THE WEDGE HIGH STEADILY BREAKS
DOWN. EXPECT VFR CONDITIONS TO DOMINATE THEREAFTER. THERE ARE SOME
CONCERNS FOR STRATUS REDEVELOPING EARLY SATURDAY WITH ABUNDANT
MOISTURE LIKELY BECMG PINNED UNDERNEATH A NOCTURNAL INVERSION.
TABULAR GUIDANCE IS NOT OVERLY BULLISH ON LOW CLOUDS OVERNIGHT...
SO WILL KEEP CONDITIONS VFR FOR NOW.
EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CIGS/VSBYS ARE POSSIBLE
AT BOTH TERMINALS SATURDAY NIGHT THROUGH SUNDAY MORNING DUE TO
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A LOW PRESSURE SYSTEM
MOVING UP THE SOUTHEAST COASTLINE.
&&
.MARINE...
NORTHEAST WINDS WILL GRADUALLY VEER TO THE SOUTHEAST TODAY AS THE
INLAND WEDGE BREAKS DOWN AND TURN SOUTHWEST BY TONIGHT. BOTH WINDS
AND SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY THRESHOLDS...ALTHOUGH
SEAS WILL BE DOMINATED BY A NORTHEAST SWELL WITH PERIODS OF 11-13
SECONDS.
SATURDAY THROUGH TUESDAY...WINDS AND SEAS WILL INCREASE LATE
SATURDAY...AS A STRENGTHENING LOW PRESSURE SYSTEM TRACKS FROM THE
NORTHEAST GULF OF MEXICO OVER OR JUST EAST OF THE WATERS SUNDAY.
SMALL CRAFT ADVISORIES MAY BE NEEDED AS EARLY AS SATURDAY NIGHT
DUE TO BUILDING SEAS...WITH WINDS POSSIBLY REACHING CRITERIA
SUNDAY AND MONDAY WITHIN COLD ADVECTION AND A TIGHT GRADIENT
BEHIND THE SYSTEM. EXPECT GRADUALLY IMPROVING CONDITIONS INTO
TUESDAY AS COASTAL LOW PULLS AWAY TO THE NORTHEAST.
RIP CURRENTS...INCREASING SWELLS COMBINED WITH ONSHORE FLOW AND
ASTRONOMICAL INFLUENCES WILL YIELD AN ENHANCED RISK FOR RIP
CURRENTS TODAY. AN ENHANCED RISK FOR RIP CURRENTS WILL REMAIN
THROUGH THE WEEKEND.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...79
AVIATION...
MARINE...79
AREA FORECAST DISCUSSION
NWS LINCOLN IL
949 AM CDT FRI APR 20 2012
.DISCUSSION...
ISSUED 949 AM CDT FRI APR 20 2012
MAIN CONCERN THIS MORNING IS WITH TEMPERATURES. THE COLD FRONT WAS
ROUGHLY ALONG OR JUST WEST OF THE I-57 CORRIDOR AS OF 9 AM.
TEMPERATURES AHEAD OF THE FRONT WERE APPROACHING 70 DEGREES IN THE
EXTREME SOUTHEAST CWA...WHERE CLOUDS HAVE ONLY RECENTLY BEGAN TO
THICKEN. BEHIND THE FRONT...TEMPERATURES HAVE DIPPED INTO THE 40S.
LATEST HRRR SHOWS THE FRONT REACHING LAWRENCEVILLE IN THE NOON TO
1 PM TIME FRAME. COLD AIR ADVECTION AND EXTENSIVE CLOUDINESS
BEHIND THE FRONT WILL RESULT IN LITTLE OR NO RISE IN TEMPERATURES
THIS AFTERNOON ACROSS THE NORTHWEST HALF OF THE CWA...WITH FALLING
TEMPERATURES IN THE SOUTHEAST HALF.
RAIN SHOWERS CONTINUE TO ADVANCE ACROSS THE CWA IN ROUGHLY A 50
MILE WIDE BAND...SO PRECIPITATION HAS LARGELY ENDED WEST OF A
BLOOMINGTON TO TAYLORVILLE LINE. MOST OF THE PRECIPITATION SHOULD
BE OUT OF THE CWA BY MID AFTERNOON...EXCEPT IN THE FAR SOUTHEAST.
ZONE/GRID UPDATES WILL BE OUT AROUND 10 AM TO UPDATE THE
TEMPERATURE AND RAINFALL TRENDS.
GEELHART
&&
.AVIATION...
ISSUED 654 AM CDT FRI APR 20 2012
A COLD FRONT HAS CLEARED KPIA/KBMI/KSPI TERMINALS...AND WILL CLEAR
KDEC/CMI WITHIN THE NEXT FEW HOURS. LIGHT SHOWERS END QUICKLY IN
THE WAKE OF THE FRONT...THOUGH A FEW HOURS OF IFR CIGS ARE LIKELY
BETWEEN WHEN THE RAIN ENDS AND SOME DRIER LOW LEVEL AIR FILTERS
IN. HIGH PRESSURE WILL PUSH INTO THE AREA LATER TONIGHT...
RESULTING IN GRADUAL CLEARING. GUSTY NORTHWEST WINDS IN THE WAKE
OF THE FRONT WILL TREND NORTHERLY AND BECOME LIGHT TONIGHT AS THE
HIGH PRESSURE BUILDS IN.
BAK
&&
.PREV DISCUSSION...
ISSUED 309 AM CDT FRI APR 20 2012
SHORT TERM...TODAY THROUGH SUNDAY
COLD FRONT WILL PUSH EASTWARD ACROSS THE AREA TODAY...ACCOMPANIED
BY A BAND OF LIGHT SHOWERS. 00Z UPPER AIR ANALYSIS SHOWS LIMITED
MOISTURE FOR THE FRONT TO WORK WITH...WITH ONLY A NARROW RIBBON OF
5-10C 850MB DEWPOINTS EXTENDING FROM TEXAS NORTHEASTWARD INTO
IOWA. IN ADDITION...00Z KILX AND KDVN UPPER AIR SOUNDINGS FEATURED
A VERY DRY LOW-LEVEL AIRMASS BELOW 600MB. HRRR AND 4KM WRF-NMM
BOTH SUGGEST THE BAND OF SHOWERS WILL GRADUALLY DISSIPATE AS IT
WORKS ITS WAY INTO THE DRIER ENVIRONMENT ACROSS CENTRAL ILLINOIS
THIS MORNING. LATEST RADAR MOSAIC CONTINUES TO INDICATE A WEAKENING
TREND...WHILE IR SATELLITE SHOWS WARMING CLOUD TOPS. END RESULT
WILL BE A BRIEF PERIOD OF SCATTERED SHOWERS ALONG AND IMMEDIATELY
BEHIND THE FRONT. RAINFALL TOTALS WILL REMAIN LIGHT...GENERALLY
UNDER ONE TENTH OF AN INCH. ONCE THE FRONT PASSES...BREEZY AND
COOLER CONDITIONS WILL SPILL INTO THE REGION LATER THIS MORNING
INTO THE AFTERNOON. WITH OVERCAST CONDITIONS AND NORTHWESTERLY
WINDS GUSTING TO 25 MPH AT TIMES...TEMPS WILL HOVER IN THE LOWER
TO MIDDLE 50S BEHIND THE FRONT.
EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY WILL ENSURE MOSTLY
CLOUDY CONDITIONS THROUGH EARLY EVENING...WITH CLEARING SKIES
DEVELOPING ACROSS THE ILLINOIS RIVER VALLEY TOWARD MIDNIGHT...THEN
FURTHER EAST ACROSS THE REMAINDER OF THE AREA OVERNIGHT. PATCHY
FROST WILL BE POSSIBLE ALONG AND NORTHWEST OF A RUSHVILLE TO
BLOOMINGTON-NORMAL LINE...WHERE SKIES WILL CLEAR EARLIEST AND
WINDS WILL DIMINISH TO LESS THAN 5 MPH. OVERNIGHT LOWS WILL RANGE
FROM THE MIDDLE 30S NORTHWEST...TO THE LOWER 40S FAR SOUTHEAST.
COOL/DRY WEATHER WILL BE ON TAP FOR SATURDAY...WITH HIGHS ONLY
REACHING THE MIDDLE TO UPPER 50S. LOW TEMPS SATURDAY NIGHT WILL
LIKELY BE A COUPLE OF DEGREES WARMER THAN TONIGHT DUE TO CLOUD
COVER FROM AN APPROACHING UPPER-LEVEL DISTURBANCE...SO CHANCES FOR
FROST WILL BE REDUCED. IN FACT...MODELS ARE TRYING TO SQUEEZE OUT
SOME LIGHT QPF WITH THE APPROACHING WAVE...HOWEVER THINK AIRMASS
WILL BE TOO DRY TO SUPPORT MEASURABLE PRECIP...SO HAVE MAINTAINED A
DRY FORECAST.
LONG TERM...MONDAY THROUGH THURSDAY
DEEP UPPER LOW IS EXPECTED TO DEVELOP OVER THE EASTERN CONUS EARLY
NEXT WEEK...WITH MODELS STILL VARYING ON ITS EVENTUAL DEPARTURE.
GIVEN HIGHLY AMPLIFIED NATURE OF THE FLOW...THINK SLOWER IS THE
WAY TO GO. END RESULT WILL BE COOL/DRY WEATHER THROUGH AT LEAST
TUESDAY...WITH A MARKED WARMING TREND BEGINNING BY THE MIDDLE OF
THE WEEK AS UPPER HEIGHTS BEGIN TO RISE. HIGH TEMPS WILL START OUT
IN THE LOWER 60S ON MONDAY...THEN WILL CLIMB WELL INTO THE 70S BY
WEDNESDAY AND THURSDAY. RAIN CHANCES THROUGH THE PERIOD APPEAR TO
BE RATHER MINIMAL...WITH THE BEST SHOT AT PRECIP OCCURRING ON
WEDNESDAY AS WARMER AIRMASS BEGINS TO MAKE ITS RETURN.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
654 AM CDT FRI APR 20 2012
.DISCUSSION...
ISSUED 309 AM CDT FRI APR 20 2012
SHORT TERM...TODAY THROUGH SUNDAY
COLD FRONT WILL PUSH EASTWARD ACROSS THE AREA TODAY...ACCOMPANIED
BY A BAND OF LIGHT SHOWERS. 00Z UPPER AIR ANALYSIS SHOWS LIMITED
MOISTURE FOR THE FRONT TO WORK WITH...WITH ONLY A NARROW RIBBON OF
5-10C 850MB DEWPOINTS EXTENDING FROM TEXAS NORTHEASTWARD INTO
IOWA. IN ADDITION...00Z KILX AND KDVN UPPER AIR SOUNDINGS FEATURED
A VERY DRY LOW-LEVEL AIRMASS BELOW 600MB. HRRR AND 4KM WRF-NMM
BOTH SUGGEST THE BAND OF SHOWERS WILL GRADUALLY DISSIPATE AS IT
WORKS ITS WAY INTO THE DRIER ENVIRONMENT ACROSS CENTRAL ILLINOIS
THIS MORNING. LATEST RADAR MOSAIC CONTINUES TO INDICATE A WEAKENING
TREND...WHILE IR SATELLITE SHOWS WARMING CLOUD TOPS. END RESULT
WILL BE A BRIEF PERIOD OF SCATTERED SHOWERS ALONG AND IMMEDIATELY
BEHIND THE FRONT. RAINFALL TOTALS WILL REMAIN LIGHT...GENERALLY
UNDER ONE TENTH OF AN INCH. ONCE THE FRONT PASSES...BREEZY AND
COOLER CONDITIONS WILL SPILL INTO THE REGION LATER THIS MORNING
INTO THE AFTERNOON. WITH OVERCAST CONDITIONS AND NORTHWESTERLY
WINDS GUSTING TO 25 MPH AT TIMES...TEMPS WILL HOVER IN THE LOWER
TO MIDDLE 50S BEHIND THE FRONT.
EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY WILL ENSURE MOSTLY
CLOUDY CONDITIONS THROUGH EARLY EVENING...WITH CLEARING SKIES
DEVELOPING ACROSS THE ILLINOIS RIVER VALLEY TOWARD MIDNIGHT...THEN
FURTHER EAST ACROSS THE REMAINDER OF THE AREA OVERNIGHT. PATCHY
FROST WILL BE POSSIBLE ALONG AND NORTHWEST OF A RUSHVILLE TO
BLOOMINGTON-NORMAL LINE...WHERE SKIES WILL CLEAR EARLIEST AND
WINDS WILL DIMINISH TO LESS THAN 5 MPH. OVERNIGHT LOWS WILL RANGE
FROM THE MIDDLE 30S NORTHWEST...TO THE LOWER 40S FAR SOUTHEAST.
COOL/DRY WEATHER WILL BE ON TAP FOR SATURDAY...WITH HIGHS ONLY
REACHING THE MIDDLE TO UPPER 50S. LOW TEMPS SATURDAY NIGHT WILL
LIKELY BE A COUPLE OF DEGREES WARMER THAN TONIGHT DUE TO CLOUD
COVER FROM AN APPROACHING UPPER-LEVEL DISTURBANCE...SO CHANCES FOR
FROST WILL BE REDUCED. IN FACT...MODELS ARE TRYING TO SQUEEZE OUT
SOME LIGHT QPF WITH THE APPROACHING WAVE...HOWEVER THINK AIRMASS
WILL BE TOO DRY TO SUPPORT MEASURABLE PRECIP...SO HAVE MAINTAINED A
DRY FORECAST.
LONG TERM...MONDAY THROUGH THURSDAY
DEEP UPPER LOW IS EXPECTED TO DEVELOP OVER THE EASTERN CONUS EARLY
NEXT WEEK...WITH MODELS STILL VARYING ON ITS EVENTUAL DEPARTURE.
GIVEN HIGHLY AMPLIFIED NATURE OF THE FLOW...THINK SLOWER IS THE
WAY TO GO. END RESULT WILL BE COOL/DRY WEATHER THROUGH AT LEAST
TUESDAY...WITH A MARKED WARMING TREND BEGINNING BY THE MIDDLE OF
THE WEEK AS UPPER HEIGHTS BEGIN TO RISE. HIGH TEMPS WILL START OUT
IN THE LOWER 60S ON MONDAY...THEN WILL CLIMB WELL INTO THE 70S BY
WEDNESDAY AND THURSDAY. RAIN CHANCES THROUGH THE PERIOD APPEAR TO
BE RATHER MINIMAL...WITH THE BEST SHOT AT PRECIP OCCURRING ON
WEDNESDAY AS WARMER AIRMASS BEGINS TO MAKE ITS RETURN.
BARNES
&&
.AVIATION...
ISSUED 654 AM CDT FRI APR 20 2012
A COLD FRONT HAS CLEARED KPIA/KBMI/KSPI TERMINALS...AND WILL CLEAR
KDEC/CMI WITHIN THE NEXT FEW HOURS. LIGHT SHOWERS END QUICKLY IN
THE WAKE OF THE FRONT...THOUGH A FEW HOURS OF IFR CIGS ARE LIKELY
BETWEEN WHEN THE RAIN ENDS AND SOME DRIER LOW LEVEL AIR FILTERS
IN. HIGH PRESSURE WILL PUSH INTO THE AREA LATER TONIGHT...
RESULTING IN GRADUAL CLEARING. GUSTY NORTHWEST WINDS IN THE WAKE
OF THE FRONT WILL TREND NORTHERLY AND BECOME LIGHT TONIGHT AS THE
HIGH PRESSURE BUILDS IN.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
640 AM CDT FRI APR 20 2012
.UPDATE...
BASED ON RADAR AND RUC TRENDS THE THREAT OF MEASURABLE
PRECIPITATION FOR THE CWFA IS NOW OVER. RUC CONTINUES TO SHOW F
VECTOR CONVERGENCE AND REASONABLY LOW CONDENSATION PRESSURE
DEFICITS THIS MORNING WHICH MAY ALLOW PATCHY DRIZZLE OR SPRINKLES
TO BE SEEN. ANY PRECIP WILL END FROM WEST TO EAST DURING THE
MORNING HOURS.
DPROG/DT OF THE MODELS INDICATE HIGH LEVEL MOISTURE INCREASING
TONIGHT WHICH STRONGLY SUGGESTS THE CI/CS ASSOCIATED WITH THE
SHORTWAVE TOPPING THE RIDGE IN THE PAC NW WILL ARRIVE AFTER
MIDNIGHT. IF THIS TREND IS CORRECT...THE HIGH LEVEL CLOUD COVER
WOULD HAVE AN IMPACT ON TEMPERATURES TONIGHT WHICH WOULD THEN PLAY
SIGNIFICANTLY INTO ANY FROST AND FREEZE POTENTIAL.
AN UPDATE REFLECTING THE IMMEDIATE SHORT TERM TRENDS WILL BE
AVAILABLE SHORTLY. ..08..
&&
.AVIATION...
LIFR TO LOW MVFR CONDITIONS WILL SLOWLY IMPROVE TO VFR CONDITIONS
THROUGH 00Z/21 WITH GUSTY WINDS. PATCHY DRIZZLE OR SPRINKLES MAY BE
POSSIBLE THROUGH 18Z/20. AFT 00Z/21 WINDS WILL DIMINISH AS HIGH
PRESSURE QUICKLY MOVES THROUGH THE AREA. ..08..
&&
.PREV DISCUSSION... /ISSUED 345 AM CDT FRI APR 20 2012/
SYNOPSIS...
06Z SFC ANALYSIS HAS THE LOW JUST SOUTHEAST OF THE QUAD CITIES WITH
A WARM FRONT EAST TO THE SOUTH SUBURBS OF CHICAGO. THE COLD FRONT
RAN INTO SOUTHWEST MISSOURI. DEW POINTS AROUND THE FRONTS WERE IN
THE 50S WITH MAINLY 40S OVER MOST OF THE PLAINS AND MIDWEST. DEW
POINTS IN THE 30S WERE IN THE UPPER MIDWEST AND WESTERN GREAT LAKES.
RADAR TRENDS THE PAST SEVERAL HOURS SHOW A BACK EDGE OF THE MORE
SUBSTANTIAL PRECIPITATION FROM ROUGHLY KRFD TO KUIN. SFC OBS
REPORTED DZ OR VERY LIGHT RAIN BACK INTO EASTERN AND CENTRAL IOWA.
SHORT TERM...TODAY AND TONIGHT
RUC TRENDS WITH CONDENSATION PRESSURE DEFICITS HAVE BEEN USEFUL IN
DEPICTING PRECIPITATION TRENDS AND WERE USED FOR THE IMMEDIATE SHORT
TERM.
BASED ON RADAR AND RUC TRENDS...ANY MEASURABLE PRECIPITATION SHOULD
BE ACROSS THE FAR EAST AND SOUTHEAST PARTS OF THE CWFA AT 12Z. THE
REMAINDER OF THE AREA SHOULD SEE DRIZZLE/SPRINKLES DUE TO LOW
CONDENSATION PRESSURE DEFICITS COMBINED WITH FORCING AND F VECTOR
CONVERGENCE THROUGH MID MORNING. AS CONDENSATION PRESSURE DEFICITS
RISE THE PRECIPITATION WILL END FROM WEST TO EAST FROM LATE MORNING
THROUGH MID DAY.
CLOUD COVER AND INITIAL PRECIPITATION THIS MORNING WILL HOLD
TEMPERATURES DOWN BUT CLEARING DURING THE MID TO LATE AFTERNOON FROM
WEST TO EAST SHOULD ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MID
50S.
TONIGHT...QUIET AND CHILLY CONDITIONS WILL BE SEEN ACROSS THE AREA.
HIGH PRESSURE OVER THE AREA WILL ALLOW WINDS TO BECOME LIGHT WITH
FROST POSSIBLE. THE POSSIBILITY DOES EXIST THAT A FREEZE MAY OCCUR
ACROSS ABOUT THE NORTHERN QUARTER TO THIRD OF THE CWFA. HOWEVER...
THE MODELS ARE SHOWING INCREASES IN MOISTURE ALOFT AFTER MIDNIGHT
SUGGESTING CI/CS MOVING INTO THE AREA. IF THIS OCCURS TEMPERATURES
WOULD BE HELD UP...POSSIBLY ABOVE FREEZING.
GIVEN THIS UNCERTAINTY...ANY DECISION REGARDING FROST/FREEZE
HEADLINES WILL BE DEFERRED TO THE NEXT SHIFT. ..08..
LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
OUR NEXT PRECIPITATION CHANCES COME ON SATURDAY AND SATURDAY
NIGHT AS A WEAK SHORTWAVE WITH A WING OF WARM AIR ADVECTION AND
ISENTROPIC LIFT AHEAD OF THE SHORTWAVE. THERE IS JUST ENOUGH
MOISTURE FOR THIS TO SQUEEZE OUT SOME SHOWERS...THOUGH MODELS ARE
SHOWING SOME DIFFERENCES WITH THIS RELATIVELY WEAK FEATURE. NAM
IS THE ODD MODEL OUT THIS MORNING...AS IT IS FARTHER EAST AND
SLIGHTLY WEAKER THAN THE OTHER MODELS HAVE. HAVE IN GENERAL TRIED
TO FOLLOW A BLEND OF THE GFS/ECMWF/UKMET SOLUTIONS ON THIS
FEATURE. WHILE THE MID LEVEL CONVERGENCE SEEMS TO LINGER ON SUNDAY
AND SUNDAY NIGHT...IT DOES NOT APPEAR THAT THERE IS ENOUGH
MOISTURE TO GET ANY SHOWERS GOING AGAIN ON SUNDAY. FOR NOW THE
TIME RANGE WITH THE HIGHEST POTENTIAL FOR PRECIPITATION IS
SATURDAY NIGHT. TEMPERATURES TO BE A LITTLE COOLER ON SATURDAY
WITH THE BAND OF PRECIPITATION MOVING INTO THE AREA...BUT
GRADUALLY WARM FOR SUNDAY AS THE MID LEVEL WARM AIR ADVECTION SETS
BACK IN QUICKLY BEHIND THE SHORTWAVE.
WE REMAIN IN STRONG NORTHWEST FLOW ON MONDAY THROUGH AT LEAST
WEDNESDAY...WITH STRONGLY AMPLIFIED FLOW OVER THE CONUS...WITH THE
DEEP TROUGH OVER THE EAST AND STRONG RIDGE OUT WEST. IT IS
DIFFICULT TO GET A GULF FEED FROM A SOUTHWEST LOW LEVEL FEED OUT OF
THIS TYPE OF SYSTEM...SO MOST SYSTEMS ARE GOING TO HAVE TO DRAG IN
THEIR OWN MOISTURE FROM THE PACIFIC...AND THEN MAKE THEIR WAY OVER
THE RIDGE. TUESDAY AND WEDNESDAY HAVE ANOTHER CHANCE FOR
PRECIPITATION AS WE GET A SLIGHTLY STRONGER SHORTWAVE THROUGH HERE.
SOME MODELS ARE EVEN BRINGING A SURFACE LOW ACROSS THE REGION.
OTHERS SIMPLY SETTLE A TROUGH AXIS ACROSS THE AREA. TOUGH CALL FOR
NOW...AND HAVE MAINTAINED SLIGHT CHANCE OR EVEN LOW CHANCE POP FOR
THE SOUTHERN PORTIONS OF THE FORECAST AREA. AS MOISTURE IS A
LIMITING FACTOR FOR THIS STORM...DO NOT ANTICIPATE HAVING ENOUGH
MOISTURE TO ACT UPON...NOR CAN WE EXPECT A REINFORCING SYSTEM TO
MOVE THROUGH LATER ON IN THE EVENING. ..LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
829 AM EDT FRI APR 20 2012
.SYNOPSIS...
QUIET AND WARM CONDITIONS WILL CONTINUE TODAY. A SLOW MOVING COLD
FRONT WILL PROVIDE THE RISK FOR SHOWERS AND EVEN A FEW
THUNDERSTORMS TONIGHT AND SATURDAY. MUCH COOLER AIR WILL SETTLE IN
BEHIND THE FRONT ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SMALL UPDATES MADE TO CUT BACK CLOUD COVER EXPECTATIONS THIS
AFTERNOON. THE FIRST FEW FRAMES OF VISIBLE SATELLITE IMAGERY
INDICATE THE HIGH CLOUD COVERAGE IS NOT QUITE AS EXPANSIVE AS
WOULD BE SUGGESTED BY NWP. ADDITIONALLY...WITH CLEARER SKIES...850
MB TEMPERATURES SURGING ROUGHLY 2C FROM YESTERDAY...AND BETTER
MIXING LIKELY TODAY RELATIVE TO YESTERDAY...TEMPERATURES LOOK TO
BE AT LEAST 4F HIGHER TODAY THAN YESTERDAY. AS A
RESULT...TEMPERATURE EXPECTATIONS WERE ADJUSTED UPWARD A BIT FOR
THIS AFTERNOON. FRIES
PREVIOUS DISCUSSION...
SLOW MOVING ANA-FRONT WILL MOVE ACROSS THE MIDWEST THIS MORNING
AND INTO WESTERN OHIO BY LATE AFTERNOON. RELATIVELY DRY AIR WILL
REMAIN IN PLACE OVER THE UPPER OHIO VALLEY TODAY, SO EXPECT DRY
CONDITIONS AND DECENT AMOUNT OF SUNSHINE, DESPITE INCREASING HIGH
CLOUDS.
MADE SMALL ADJUSTMENTS TO THE COVERAGE OF THE INCREASING CLOUDS
PER RECENT SATELLITE DATA AND RUC MODEL OUTPUT. MADE SMALL
EXPECT HIGH TEMPERATURES THIS AFTERNOON TO BE MORE THAN 10 DEGREES
WARMER THAN NORMAL PER RECENT GFS AND NAM MOS AND HRRR MODEL
OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
FRONT WILL REACH THE WESTERN EDGE OF THE CWA THIS EVENING. SHOWERS
ASSOCIATED WITH THE BOUNDARY, ARE POSITIONED BEHIND THE FRONT WITH
THE MAIN UL SHORTWAVE. MODELS IN DECENT AGREEMENT SHOWING THE
FRONT LOSING SOME OF ITS BUNCH AS IT BEGINS TO ENCOUNTER THE DRIER
AND MORE STABLE AIR OVER THE UPPER OHIO VALLEY. CONFIDENCE IS LOW
ON HOW MUCH CONVECTION TO EXPECT LATER TODAY. THE LL DO DESTABILIZE
THIS AFTERNOON RIGHT AHEAD OF THE FRONT AS HIGHER SFC TDS SURGE
NORTHWARD. CURRENT FORECAST SOUNDINGS ARE INDICATING CONVECTIVE
TEMPS IN THE LOWER 80S, WHICH MAY BE JUST A BIT TOO HIGH, BUT IT
WILL BE CLOSE. ALL OF THE UL SUPPORT IS BEHIND THE FRONT AND THE
DEEP LAYERED MOISTURE IS BEHIND THE BOUNDARY AS WELL. FOR NOW WILL
LEAVE IN A MENTION FOR THE CHANCE FOR STORMS THIS EVENING, BUT
WILL REMOVE MENTION BY LATE EVENING AND EARLY SAT MORNING.
EXPECT AN AREA OF WIDESPREAD SHOWERS TO SLOWLY MOVE THROUGH LATE
TONIGHT, WITH EASTERN EDGES OF THE FORECAST AREA NOT SEEING MUCH
ACTIVITY UNTIL CLOSE TO DAWN.
SHOWER ACTIVITY WILL DIMINISH OVER THE WESTERN HALF OF THE AREA BY
LATE SAT MORNING, BUT WILL NOT EXIT THE EAST UNTIL THE EVENING.
DRAMATIC COOLING LOOKS SET FOR SATURDAY AS THE FRONT SLIDES EAST
OF THE AREA AND 850 MB TEMPERATURES DIVE FROM NEAR +10C IN THE
MORNING TO ABOUT +2C BY EVENING. WITH THIS KIND OF ADVECTION AT
850 MB...IT STANDS TO REASON THAT SURFACE PRESSURE GRADIENTS WILL
FAVOR STRONG/GUSTY NORTHWEST WINDS ON SATURDAY. THESE WINDS WILL
WEAKEN INTO SATURDAY NIGHT AND SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
VERY LOW CONFIDENCE FOR THE LONG TERM, AS MODEL SOLUTIONS ARE
BEGINNING TO GREATLY DIFFER. LATEST NAM/SREF/GEMS/CMC ARE SHOWING
AN EAST COAST LOW DEVELOPING EARLY NEXT WEEK, BUT REMAINING FAR
ENOUGH EAST TO HAVE LITTLE EFFECT ON THE AREA. HOWEVER THE OP
GFS/OP ECMWF ARE PROVIDING A MUCH DIFFERENT STORY DEVELOPING A
STRONG SFC LOW OFF THE CAROLINAS SUNDAY AFTERNOON AND THEN MOVING
IT NORTHWARD AND EVENTUALLY NORTHWESTWARD. AT THE SAME TIME, THE
LOW RAPIDLY DEEPENS. THIS WOULD MEAN A MUCH DIFFERENT FORECAST FOR
EARLY NEXT WEEK WITH RAIN, WINDY CONDITIONS, AND COLD TEMPS. HAVE
DECIDED TO MAKE LITTLE CHANGES TO THE LONG TERM, AS IT IS CLOSER
TO ENSEMBLE FORECAST AND FEEL FOR NOW THIS WOULD BE THE BEST WAY
TO GO.
&&
.AVIATION /13Z FRIDAY THROUGH TUESDAY/...
RECENT SURFACE AND SATELLITE DATA, COUPLED WITH SREF MODEL OUTPUT,
SHOW VFR CONTINUING ACROSS THE UPPER OHIO VALLEY INTO 06Z SATURDAY,
WITH LITTLE MORE SCATTERED DAYTIME CUMULUS AND BANDS OF ALTOCUMULUS
AND CIRRUS. SREF MODEL OUTPUT THEN SHOWS A COLD ANAFRONTAL BAND OF
MVFR RAIN SHOWERS MOVING EASTBOUND THROUGH THE AREA.
SURFACE WINDS WILL BE FROM THE SOUTH, WITH DAYTIME VERTICAL MIXING
CAUSING GUSTS TO 20 KTS THIS AFTERNOON.
OUTLOOK...SATURDAY THROUGH TUESDAY...
RESTRICTIONS LIKELY SATURDAY DUE TO LINGERING POSTFRONTAL SHOWERS
SATURDAY MORNING AND COLD POOL CLOUDINESS SATURDAY AFTERNOON AND
NIGHT. EXPECT TREND TOWARD VFR SUNDAY INTO TUESDAY, DESPITE
POSSIBLE LINGERING OF COLD POOL CLOUDINESS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
630 AM EDT FRI APR 20 2012
.SYNOPSIS...
QUIET AND WARM CONDITIONS WILL CONTINUE TODAY. A SLOW MOVING COLD
FRONT WILL PROVIDE THE RISK FOR SHOWERS AND EVEN A FEW
THUNDERSTORMS TONIGHT AND SATURDAY. MUCH COOLER AIR WILL SETTLE IN
BEHIND THE FRONT ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SLOW MOVING ANA-FRONT WILL MOVE ACROSS THE MIDWEST THIS MORNING
AND INTO WESTERN OHIO BY LATE AFTERNOON. RELATIVELY DRY AIR WILL
REMAIN IN PLACE OVER THE UPPER OHIO VALLEY TODAY, SO EXPECT DRY
CONDITIONS AND DECENT AMOUNT OF SUNSHINE, DESPITE INCREASING HIGH
CLOUDS.
MADE SMALL ADJUSTMENTS TO THE COVERAGE OF THE INCREASING CLOUDS
PER RECENT SATELLITE DATA AND RUC MODEL OUTPUT. MADE SMALL
EXPECT HIGH TEMPERATURES THIS AFTERNOON TO BE MORE THAN 10 DEGREES
WARMER THAN NORMAL PER RECENT GFS AND NAM MOS AND HRRR MODEL
OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
FRONT WILL REACH THE WESTERN EDGE OF THE CWA THIS EVENING. SHOWERS
ASSOCIATED WITH THE BOUNDARY, ARE POSITIONED BEHIND THE FRONT WITH
THE MAIN UL SHORTWAVE. MODELS IN DECENT AGREEMENT SHOWING THE
FRONT LOSING SOME OF ITS BUNCH AS IT BEGINS TO ENCOUNTER THE DRIER
AND MORE STABLE AIR OVER THE UPPER OHIO VALLEY. CONFIDENCE IS LOW
ON HOW MUCH CONVECTION TO EXPECT LATER TODAY. THE LL DO DESTABILIZE
THIS AFTERNOON RIGHT AHEAD OF THE FRONT AS HIGHER SFC TDS SURGE
NORTHWARD. CURRENT FORECAST SOUNDINGS ARE INDICATING CONVECTIVE
TEMPS IN THE LOWER 80S, WHICH MAY BE JUST A BIT TOO HIGH, BUT IT
WILL BE CLOSE. ALL OF THE UL SUPPORT IS BEHIND THE FRONT AND THE
DEEP LAYERED MOISTURE IS BEHIND THE BOUNDARY AS WELL. FOR NOW WILL
LEAVE IN A MENTION FOR THE CHANCE FOR STORMS THIS EVENING, BUT
WILL REMOVE MENTION BY LATE EVENING AND EARLY SAT MORNING.
EXPECT AN AREA OF WIDESPREAD SHOWERS TO SLOWLY MOVE THROUGH LATE
TONIGHT, WITH EASTERN EDGES OF THE FORECAST AREA NOT SEEING MUCH
ACTIVITY UNTIL CLOSE TO DAWN.
SHOWER ACTIVITY WILL DIMINISH OVER THE WESTERN HALF OF THE AREA BY
LATE SAT MORNING, BUT WILL NOT EXIT THE EAST UNTIL THE EVENING.
DRAMATIC COOLING LOOKS SET FOR SATURDAY AS THE FRONT SLIDES EAST
OF THE AREA AND 850 MB TEMPERATURES DIVE FROM NEAR +10C IN THE
MORNING TO ABOUT +2C BY EVENING. WITH THIS KIND OF ADVECTION AT
850 MB...IT STANDS TO REASON THAT SURFACE PRESSURE GRADIENTS WILL
FAVOR STRONG/GUSTY NORTHWEST WINDS ON SATURDAY. THESE WINDS WILL
WEAKEN INTO SATURDAY NIGHT AND SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
VERY LOW CONFIDENCE FOR THE LONG TERM, AS MODEL SOLUTIONS ARE
BEGINNING TO GREATLY DIFFER. LATEST NAM/SREF/GEMS/CMC ARE SHOWING
AN EAST COAST LOW DEVELOPING EARLY NEXT WEEK, BUT REMAINING FAR
ENOUGH EAST TO HAVE LITTLE EFFECT ON THE AREA. HOWEVER THE OP
GFS/OP ECMWF ARE PROVIDING A MUCH DIFFERENT STORY DEVELOPING A
STRONG SFC LOW OFF THE CAROLINAS SUNDAY AFTERNOON AND THEN MOVING
IT NORTHWARD AND EVENTUALLY NORTHWESTWARD. AT THE SAME TIME, THE
LOW RAPIDLY DEEPENS. THIS WOULD MEAN A MUCH DIFFERENT FORECAST FOR
EARLY NEXT WEEK WITH RAIN, WINDY CONDITIONS, AND COLD TEMPS. HAVE
DECIDED TO MAKE LITTLE CHANGES TO THE LONG TERM, AS IT IS CLOSER
TO ENSEMBLE FORECAST AND FEEL FOR NOW THIS WOULD BE THE BEST WAY
TO GO.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
RECENT SURFACE AND SATELLITE DATA, COUPLED WITH SREF MODEL OUTPUT,
SHOW VFR CONTINUING ACROSS THE UPPER OHIO VALLEY INTO 06Z SATURDAY,
WITH LITTLE MORE SCATTERED DAYTIME CUMULUS AND BANDS OF ALTOCUMULUS
AND CIRRUS. SREF MODEL OUTPUT THEN SHOWS A COLD ANAFRONTAL BAND OF
MVFR RAIN SHOWERS MOVING EASTBOUND THROUGH THE AREA.
SURFACE WINDS WILL BE FROM THE SOUTH, WITH DAYTIME VERTICAL MIXING
CAUSING GUSTS TO 20 KTS THIS AFTERNOON.
OUTLOOK...SATURDAY THROUGH TUESDAY...
RESTRICTIONS LIKELY SATURDAY DUE TO LINGERING POSTFRONTAL SHOWERS
SATURDAY MORNING AND COLD POOL CLOUDINESS SATURDAY AFTERNOON AND
NIGHT. EXPECT TREND TOWARD VFR SUNDAY INTO TUESDAY, DESPITE
POSSIBLE LINGERING OF COLD POOL CLOUDINESS.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS MARQUETTE MI
1049 AM EDT FRI APR 20 2012
.UPDATE...
ISSUED AT 1047 AM EDT FRI APR 20 2012
FCST IN FINE SHAPE. EXPECT TREND TOWARD IMPROVING WEATHER THROUGH
REST OF THE DAY. RADAR AND SFC OBS/WEB CAMS INDICATE BACK EDGE OF
PRECIPITATION FM NEAR ERY THROUGH ISQ AND ACROSS NORTHERN LK MICHIGAN
INTO DOOR COUNTY WISCONSIN. WV/RUC ANALYSIS SHOWS STRONGEST SHORTWAVE
OVR EASTERN CWA BUT ANOTHER WEAKER WAVE IS LIFTING OUT OF WI AS WELL.
BASED ON SHARPENING OF RADAR ECHOES LAST HR APPEARS THIS WAVE MAY BE
ENHANCING MID-LEVEL DEFORMATION OVR THE EASTERN CWA. RUC PICKS UP ON
THIS H7-H5 DEFORMATION AND SHOWS IT COLLAPSING 18Z-21Z AS SHORTWAVE
TROUGH MOVES EAST.
WEB CAMS SHOW MAINLY WET CONDITIONS OVR THE EAST THOUGH SOME SNOW
MAY BE MIXING IN AT TIMES WITH SFC TEMPS IN THE MIDDLE 30S. ANY SNOW
ACCUMS WILL BE MINIMAL REST OF THE MORNING. BY EARLY AFTN...PRECIP
IS EXPECTED TO BE MAINLY GONE AND SKIES SHOULD CLEAR OUT IN THE
CNTRL AND EAST. NORTHEAST WINDS PROVIDING UPSLOPE HELP AND IS HOLDING
IN POCKET OF LOWER CLOUDS OVR CNTRL CWA /SAW REPORTING OVC005 AT 14Z/
BUT ALL CLOUDS SHOULD FADE AWAY THROUGH AFTN AS LARGER SCALE FORCING
DEPARTS THE AREA. UPDATED/PUBLISHED GRIDS AND TEXT PRODUCTS ARE OUT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 543 AM EDT FRI APR 20 2012
WATER VAPOR LOOP SHOWS SHORTWAVE MOVING THROUGH WI WITH COUPLED UPR
JET STRUCTURE AND ASSOC FRONTOGENETIC FORCING SUPPORTING BAND OF
PCPN FROM NE WI INTO SCNTRL UPR MI AND NRN LOWER MI. REPORTS THUS
FAR FROM THIS PCPN BAND OVER NCNTRL/NE WI INTO MENOMINEE COUNTY
INDICATE A MIX OF RAIN AND SNOW. MOST SNOW ACCUMULATION APPEARS TO
BE LIGHT...LESS THAN AN INCH...ALTHOUGH THERE WAS A PUBLIC REPORT OF
2 INCHES IN DAGGETT...MAINLY IN GRASSY AREAS.
TODAY...GIVEN THE LACK OF ANY SIGNIFICANT SNOW ACCUMULATION REPORTS
AND THE FACT THAT PCPN UPSTREAM OVER WI APPEARS TO BE TAPERING OFF
AS NOTED ON RADAR LOOP...HAVE DECIDED TO DROP THE WINTER WX ADVISORY
FOR MENOMINEE COUNTY. MODELS SHOW UPR JET SUPPORT AND ASSOC FGEN
FORCING FALLING APART THROUGH THE MORNING HRS AS THE SYSTEM MOVES
EAST. ANY ADDITIONAL SNOW ACCUMULATION FROM THE SYSTEM OVER SCNTRL
AND ERN PORTIONS OF THE CWA WILL BE LESS THAN AN INCH BEFORE THE
PCPN ENDS LATER THIS MORNING.
THE REST OF THE CWA WILL BE QUIET AS SFC RDG BUILDS IN FROM THE WEST
IN THE WAKE OF THE LOW PRESSURE SYSTEM. MODEL SNDGS INDICATE Q-VECT
DIV SPREADING IN FROM THE WEST WITH ASSOC SHARP SUBSIDENCE/DRYING
WHICH SHOULD LEAD TO SUNSHINE FOR THE MAJORITY OF THE CWA BY LATE
MORNING/EARLY AFTN. DESPITE INCREASING SUNSHINE...LOOK FOR
TEMPERATURES TO ONLY RISE INTO THE LOWER TO MID 40S AS WE WILL BE
COLD ADVECTING IN A 10-20 KT N-NE FLOW.
TONIGHT INTO SATURDAY...HIGH PRESSURE BUILDING INTO NORTHERN ONTARIO
AND THE WESTERN GREAT LAKES WILL RESULT IN DRY BUT CONTINUED COOL
WEATHER. EXPECT IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT OVER
WRN INTERIOR LOCATIONS AS THE SFC RDG AXIS MOVES OVER THE AREA AND
PCPN WATER VALUES FALL BLO .25 INCH. EXPECT LOWS RANGING FROM THE
LOWER 20S WRN INTERIOR TO THE UPR 20S/LOWER 30S EAST AND NEAR THE
GREAT LAKES. 850MB TEMPERATURES FALLING TO AROUND -6C ON SATURDAY IN
A WEAK N-NE FLOW WILL RESULT IN HIGH TEMPS ONLY IN THE 40S FOR MOST
AREAS...EXCEPT POSSIBLY APPROACHING 50F IN A FEW LOCATONS ALONG THE
WI BDR.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 543 AM EDT FRI APR 20 2012
HIGH PRESSURE WILL BE THE RULE AT THE SFC /AT LEAST MOST OF THIS
LONG RANGE/. HOWEVER...THE 500MB PATTERN WILL NOT ALLOW US A
COMPLETELY QUIET END TO OUR WEEKEND AND WEEK AHEAD WITH DOMINANT NW
FLOW ALOFT. THE 500MB OPEN WAVE/TROUGH WILL NOT MOVE FAR BY 00Z
SUNDAY...FROM W LAKE SUPERIOR THROUGH TX EARLY THIS MORNING...TO
LAKE HURON AND THE EASTERN GULF OF MEXICO. WHILE A COUPLE OF SMALLER
DISTURBANCES WILL SLIDE IN FROM THE WEST...KEEPING THE TROUGH
NEARBY...THE MAIN FEATURE OF INTEREST WILL BE WELL TO OUR SOUTH.
WILL DISMISS THE NAM SOLUTION FOR MUCH OF THIS FORECAST PERIOD....AS
IT LOOKS TO BE ON ITS OWN...PARTICULARLY AS WE MOVE INTO SATURDAY
NIGHT AND SUNDAY. THIS IS MAINLY DUE TO THE HANDLING OF THE A 500MB
WAVE EJECTING OUR WAY FROM THE LOW CURRENTLY SET UP OVER THE GULF OF
AK. THE NAM ATTEMPTS TO WRAP IT UP OVER THE CWA SUNDAY AFTERNOON
INSTEAD OF OVER THE CENTRAL APPALACHIANS/TN VALLEY AROUND THE SAME
TIME...LIKE THE CANADIAN/GFS/ECMWF. WIND WISE ON SUNDAY THE NAM IS
ROUGHLY 10KTS STRONGER THAN THE GFS FROM THE SFC UP THROUGH AT LEAST
500MB. THE 20/06Z RUN OF THE NAM EVEN ATTEMPTS TO SPIT OUT 0.25IN
RAIN WITH THIS FEATURE...WITH LITTLE MORE THAN A FEW ADDITIONAL
CLOUDS OFF THE REMAINING MODELS. WHILE THE LATEST 20/00Z LOOKS TO
PLAY UP THE MIDDLE GROUND BETWEEN THE QUICKER GFS AND NAM.
RH VALUES MAY BE TOO HIGH FOR SUNDAY...GIVEN THE MIXED DEWPOINT
VALUES IN THE TEENS EAST. LAKE BREEZES WILL BE THE MAIN CONCERN FIRE
WISE...IN THE LOW RH AREAS. STILL...WITH SLIGHTLY BELOW NORMAL
TEMPERATURES AND OVERALL LIGHT WINDS OVERALL WILL NOT HIGHLIGHT FIRE
WEATHER TOO MUCH.
WILL NOT GET INTO TOO MANY DETAILS OF THE LATTER PART OF THIS
FORECAST...WITH THE RETROGRADING STACKED SFC/500MB LOW SLIDING UP
THE EASTERN SEABOARD SUNDAY AND MONDAY...BEFORE SHIFTING ACROSS THE
LOWER GREAT LAKES AND WESTERN QUEBEC MONDAY AFTERNOON THROUGH MONDAY
NIGHT. AT THIS POINT...MUCH OF THE PRECIP AND EVEN CLOUD COVER LOOK
TO STAY TO OUR EAST. WE CAN STILL EXPECT SOME INCREASED COOL N/NNW
WINDS OFF LAKE SUPERIOR MONDAY AFTERNOON THROUGH AT LEAST TUESDAY
OVER THE EAST HALF OF THE CWA. EVEN WITH THIS FEATURE NEARING...LOOK
FOR A SLOW BUT STEADY WARMUP FROM MONDAY THROUGH THURSDAY...WITH
HIGH TEMPS IN THE MID 50S TO NEAR 60F BY THURSDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 543 AM EDT FRI APR 20 2012
MAIN CONCERN OF THE FORECAST PERIOD WILL FOCUS ON TIMING OF LOW
CLOUD DECK LIFTING AT KSAW WHICH SHOULD OCCUR BY EARLY AFTERNOON.
PCPN SHOULD GENERALLY STAY SOUTH AND EAST OF KSAW SO DID NOT MENTION
ANYTHING IN TAF. EXPECT VFR CONDITIONS AT KIWD AND KCMX THROUGH THE
PERIOD UNDER INFLUENCE OF SFC RDG BUILDING IN FM THE WEST. NORTH TO
NORTHEAST WINDS COULD GET A BIT GUSTY (AOA 20 KT AT TIMES) BY LATE
MORNING/AFTERNOON...ESPECIALLY AT KSAW...WITH TIGHT PRES GRAD BTWN
DEPARTING LOW AND BUILDING HIGH FROM THE WEST.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 543 AM EDT FRI APR 20 2012
WINDS LESS THAN 30KTS WILL DOMINATE THE FORECAST PERIOD. AN EXITING
LOW TEMPORARILY ACROSS S LOWER LAKE MICHIGAN WILL PUSH ACROSS THE
LOWER GREAT LAKES THIS EVENING...MAKING WAY FOR A RIDGE TO BUILD
ACROSS THE UPPER GREAT LAKES FROM CANADA. EXPECT A STRONG LOW TO
PUSH NORTHWARD ACROSS THE EASTERN SEABOARD...MAKING ITS WAY NEAR
LAKE ONTARIO MONDAY AFTERNOON. THE RIDGE OVERHEAD WILL SLOWLY WEAKEN
AS A RESULT...AND SLOWLY BE REPLACED BY A TROUGH INVADING FROM THE
EAST MONDAY NIGHT INTO TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...VOSS
MARINE...KF
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
622 AM CDT FRI APR 20 2012
.UPDATE...
.AVIATION...
MIXED VFR/MVFR/IFR SHOULD IMPROVE TO MOSTLY VFR BY LATE MORNING.
THE RUC CONTINUES TO INDICATE A SMALL AREA OF MVFR THROUGH MID
AFTERNOON NEAR KANW-KBBW. VFR IS EXPECTED ALL AREAS BY 21Z AND
CONTINUING THROUGH 12Z SATURDAY. AN UPPER LEVEL DISTURBANCE
TRACKING THROUGH THE UPPER MIDWEST IS EXPECTED TO SPREAD BKN-
OVC100 CIGS THROUGH THE FCST AREA TONIGHT.
&&
.PREV DISCUSSION... /ISSUED 349 AM CDT FRI APR 20 2012/
SHORT TERM...TODAY THROUGH SUNDAY NIGHT
A PATTERN CHANGE IS IN STORE FOR NEBRASKA THROUGH THIS TIME
PERIOD...GOING FROM FAST FLOW WITH SYSTEMS MOVING THROUGH ALMOST
DAILY TO A BUILDING RIDGE LEADING TO DRIER AND WARMER CONDITIONS.
AT 20.08Z WATER VAPOR IMAGERY SHOWED A SHORTWAVE TROUGH OVER THE
NEBRASKA PANHANDLE WITH RIDGING UPSTREAM IN SOUTHWEST CANADA AND
ANOTHER SHORTWAVE TROUGH PUSHING INTO BRITISH COLUMBIA. GOOD
SUBSIDENCE AND DARKENING WAS SEEN BEHIND THE NEBRASKA
SHORTWAVE...AND WHEN LOOKING AT IR IMAGERY EARLY THIS
MORNING...DID SEE CLEARING SKIES ACROSS THE PANHANDLE AND FAR
WESTERN NEBRASKA. CLOUDS...ALONG WITH SHOWERS REMAINED ACROSS THE
AREA FROM SOUTHWEST TO NORTHEAST...AHEAD OF THE SHORTWAVE.
FOR TODAY THE UPPER LEVEL SHORTWAVE TROUGH WILL DIG
SOUTHEAST OF THE FORECAST AREA...ALLOWING RIDGING TO START BUILDING
INTO THE FORECAST AREA. WITH DECENT SUBSIDENCE BEHIND THE
SHORTWAVE...SHOULD CONTINUE TO SEE SKIES CLEAR...ALTHOUGH IT MAY
TAKE MUCH OF THE MORNING IN SOME PLACES AS LOW LEVEL MOISTURE BELOW
THE INVERSION MAY TAKE SOME TIME TO SCOUR OUT. WITH THE CLOUD
COVER AND WITH TEMPERATURES ALOFT BEING SLOW TO WARM UP...DON/T
EXPECT TEMPERATURES TO RISE TOO HIGH TODAY. LOOKING FOR
HIGHS...EVEN WITH SUN AROUND 60 DEGREES.
ANOTHER DISTURBANCE /THE SHORTWAVE MOVING INTO BRITISH COLUMBIA/
WILL PUSH OVER THE RIDGE TONIGHT AND ON SATURDAY. DUE TO THE RIDGE
BUILDING EAST...THE STORM TRACK WITH THIS NEXT DISTURBANCE SHOULD
STAY NORTH AND EAST OF THE FORECAST AREA. MAY GET SOME CLOUDY
SKIES LATER IN THE DAY AND INTO THE DAY SATURDAY ACROSS NORTH
CENTRAL NEBRASKA. A COLD FRONT WILL BE PUSHED SOUTHEAST ACROSS THE
AREA ON SATURDAY ASSOCIATED WITH THIS SYSTEM. BUT...WITH MOISTURE
STAYING CLOSER TO THE SURFACE LOW OVER THE DAKOTAS AND IOWA...DO
NOT ANTICIPATE THE NEED FOR ANY RAIN CHANCES IN THE FORECAST FOR
TONIGHT OR SATURDAY. THIS WILL NEED TO BE WATCHED THOUGH AS THERE
HAS BEEN THE SUGGESTION FROM A MODEL HERE AND THERE THAT SHOWERS
COULD SNEAK SOUTHWARD AND INTO THE AREA ON SATURDAY.
EVEN WITH THE PASSING OF THE COLD FRONT...TEMPERATURES ALOFT /AT
850MB/ INCREASE BY 4 TO 6 DEGREES FROM 21.00Z TO 22.00Z. SO
LOOKING AT WARMER TEMPERATURES ON SATURDAY...LIKELY IN THE UPPER
60S AND 70S ACROSS THE FORECAST AREA. CLOUD COVER OVER THE
NORTHEAST MAY SLOW WARMING UP AND MAY KEEP HIGHS A BIT
COOLER...BUT LESSER CLOUDS ARE EXPECTED OVER THE SOUTH AND WESTERN
AREAS. SOMETHING IN FAVOR OF WARMING IS THE NORTHWEST SURFACE
FLOW...CAUSING A DOWNSLOPE AND WARMING EFFECT...TO HELP WARMING
INTO THE 70S. WINDS DO LOOK TO BE A BIT BREEZY BEHIND THE PASSING
FRONT ON SATURDAY...BUT SHOULD DIMINISH BY EVENING AS HIGH
PRESSURE BUILDS IN.
THE UPPER LEVEL FLOW AMPLIFIES FURTHER ON SUNDAY AS THE TROUGH
OVER THE EASTERN CONUS DIGS INTO THE DEEP SOUTH AND THE RIDGE
BUILDS OVER THE ROCKIES. TEMPERATURES AT 850MB WILL SEE A DECENTLY
SHARP GRADIENT...VARYING FROM 6C TO 20C AT 23.00Z FROM EASTERN TO
WESTERN NEBRASKA RESPECTIVELY.
LONG TERM...MONDAY THROUGH THURSDAY
THE WORK WEEK BEGINS WILL WELL ABOVE NORMAL TEMPERATURES AS THE
MODELS CONTINUE TO HAVE A SIMILAR HANDLE ON THE UPPER LEVEL
PATTERN THROUGH TUESDAY. THROUGH THIS TIME...HIGHLY AMPLIFIED FLOW
EXISTS WITH UPPER LOWS OVER BOTH THE EASTERN CONUS AND THE EASTERN
PACIFIC...WITH STRONG RIDGING ACROSS THE WESTERN AND CENTRAL
CONUS.
GFS ENSEMBLE STANDARDIZED ANOMALIES CONTINUE TO SHOW STRONG
SIGNALS FOR WELL ABOVE NORMAL TEMPERATURES FOR MONDAY AND
TUESDAY...WITH TEMPERATURES AT 2 TO 3 STANDARD DEVIATIONS ABOVE
NORMAL FROM MONDAY THROUGH WEDNESDAY. AS STATED LAST NIGHT...DON/T
ANTICIPATE RECORD HIGHS BUT WELL ABOVE NORMAL FOR THIS TIME OF
YEAR. THE SIGNAL IS STILL THERE FOR WEDNESDAY...BUT WITH LESSER
CONFIDENCE DUE TO MODELS BEGINNING TO DIVERGE. DIFFERENCES BEYOND
TUESDAY INCLUDE THE GFS WANTING TO MOVE THE CLOSED UPPER LEVEL LOW
ACROSS THE GREAT BASIN AND INTO THE SOUTHERN PLAINS BY
THURSDAY...WHILE THE ECMWF...GEM AND GFS ENSEMBLE MEAN KEEPS THE
CLOSED LOW OFF THE CALIFORNIA COAST. MEANWHILE IN THE NORTHERN
STREAM...FOR WEDNESDAY SEVERAL SOLUTIONS WOULD SUGGEST A SLIGHT
FLATTENING OF THE RIDGE MEANING THE POSSIBILITY FOR SOME COLD AIR
ADVECTION...AND COOLER TEMPERATURES FOR WEDNESDAY. WILL TAKE A
CONSENSUS APPROACH FOR TEMPERATURES THROUGH THIS TIME AND WILL
KEEP THE FORECAST DRY THROUGH THIS TIME WITH LITTLE CONFIDENCE ON
THE TIMING OF ANY SHORTWAVE MOVING OVER THE RIDGE WITH ENOUGH
STRENGTH TO PUSH PRECIPITATION INTO NEBRASKA.
AVIATION...
THE BANK OF MVFR/LOCAL IFR CIGS ACROSS NCNTL NEB IS EXPECTED TO
CONTINUE TO ERODE THROUGH 18Z THIS MORNING. VFR IS GENERALLY
EXPECTED AFTER 18Z THROUGH 12Z SATURDAY MORNING.
ONE CAVEAT IS THAT THE RUC WHICH RUNS THROUGH ONLY 18Z THIS MORNING
SHOWS A NARROW AREA OF MVFR ALONG HWY 83 LINGERING AT 18Z. THE OTHER
MODELS SUGGEST VFR AT THIS TIME. THUS LOCAL MVFR CONDITIONS ARE
POSSIBLE 18Z THROUGH 21Z WITH VFR THEREAFTER.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/EXTENDED...CDC
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
950 AM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD INTO THE AREA
SATURDAY NIGHT AND THEN WEAKEN SUNDAY. A SURFACE LOW AND UPPER LOW WILL
MOVE SOUTH TO NORTH OVER THE EASTERN UNITED STATES EARLY NEXT WEEK
AND THIS WILL AFFECT THE WEATHER ESPECIALLY OVER NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MADE ADJUSTMENTS TO SKY COVER THIS MORNING BASED ON SATELLITE
SHOWING JUST SOME THIN MID LEVEL CLOUDS ACROSS THE AREA. THICKER
CLOUD COVER CLOSER TO THE FRONT WITH THE PRECIP BACK IN
INDIANA/ILLINOIS THIS MORNING. CONTINUING TO EXPECT SOME CU TO
DEVELOP THIS AFTERNOON BUT LEANED MORE A BIT MORE SUNSHINE. LATEST
RUNS OF THE HRRR STILL TRYING TO SHOW SOME ISOLATED SHOWERS
EARLIER IN THE AFTERNOON FOR CENTRAL PORTIONS OF THE FORECAST AREA
BUT CONTINUED TO LEAN AGAINST THAT. INCREASED TEMPS SLIGHTLY
ESPECIALLY ACROSS THE EAST. KEPT LOCATIONS BELOW RECORDS BUT WILL
CONTINUE TO WATCH THIS. PREVIOUS DISCUSSION BELOW.
THE ISSUE FOR THIS AFTERNOON IS THE TIMING OF THE PRECIPITATION. THE
MODELS AND CURRENT CONDITIONS INDICATE THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE VERY CLOSE TO THE FRONT AND BEHIND IT. THE
FRONT IS EXPECTED TO BE FROM TOL TO FDY AROUND 20Z...CLE TO MFD AT
00Z AND ERI TO YNG BY 03Z. THE HRRR MODEL IS TRYING TO INDICATE SOME
SHOWERS DEVELOPING WAY AHEAD OF THE FRONT. MOST OF THE MODELS ARE
NOT INDICATING THIS...SO PLAYED THE FORECAST THAT WAY. SPC HAS SOME
OF THE AREA IN SEE TEXT FOR POSSIBLE SEVERE THUNDERSTORMS. EXPECTING
A FAIR AMOUNT OF CUMULUS CLOUDS THIS AFTERNOON...WE SHOULD HAVE SOME
SUNSHINE TO HELP INCREASE THE CAPES TOO MUCH. WILL MENTION IN THE HWO
STRONG TO AN ISOLATED SEVERE THUNDERSTORM COULD BE POSSIBLE. THE
BEST CHANCE FOR THUNDERSTORMS WILL BE WITHIN A FEW HOURS OF
FRONTAL PASSAGE. WITH THE SOUTHWEST FLOW AND SOME SUNSHINE WENT
TOWARD THE WARMEST GUIDANCE. ATTM WITH NOT 100% SUNSHINE WE SHOULD
NOT BREAK ANY RECORDS...THE RECORD HIGHS FOR TODAY ARE IN THE
LOWER TO MID 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
THE GFS/ECMWF HANG UNTO THE SHOWERS MUCH LONGER THAN THE OTHER
MODELS. THIS SEEMS REASONABLE WITH A FAIR AMOUNT OF OMEGA AND THE
UPPER TROF MOVING THROUGH TONIGHT AND SATURDAY. HIGH PRESSURE
RIDGE TRIES TO BUILD IN SATURDAY NIGHT AND WEAKEN BY SUNDAY...SO
SATURDAY NIGHT AND SUNDAY SHOULD BE DRY. MAY HAVE TO WORRY ABOUT
SOME FROST SATURDAY NIGHT IF THE WINDS DECREASE ENOUGH AND THE
CLOUDS COVER IS NOT TOO THICK. THE BEST CHANCE FOR DECREASING
CLOUDS WILL BE NORTHWEST OHIO. WITH SOME UNCERTAINTY DID NOT
MENTION FROST ATTM IN THE GRIDS/ZONES...ONLY THE HWO.
SUNDAY NIGHT THROUGH MONDAY NIGHT ARE INTERESTING WITH THE SURFACE LOW
AND UPPER LOW MOVING SOUTH TO NORTH OVER THE EASTERN UNITED
STATES. INTRODUCING CHANCE POPS OVER THE EASTERN PORTION OF THE
FORECAST AREA AND WITH THE AIR COLD ENOUGH A CHANCE OF RAIN OR
SNOW. NORTHWEST OHIO SHOULD REMAIN MAINLY DRY FROM THE
SYSTEM...THIS WILL HAVE TO BE WATCHED.
TENDED ON THE COOLER SIDE FOR THE TEMPERATURES.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A LOT OF UNCERTAINTY FROM TUESDAY ONWARD WITH THE FORECAST. TUESDAY
WILL DEPEND ON WHAT ENDS UP HAPPENING WITH THE EAST COAST LOW THAT
IS FORECAST TO CROSS NEW ENGLAND. HOW MUCH COLD/COOL AIR WILL BE
DRAWN SOUTHWARD WITH THIS. WITH A COUPLE RUNS WITH THIS GENERAL
SOLUTION HAVE LOWERED HIGH TEMPS ON TUESDAY AND WEDNESDAY AND THEY
WILL BE SITTING 5 TO 10 DEGREES BELOW NORMAL. THERE IS A LOT OF
SWING IN WHICH WAY THIS WILL TURN OUT. EVENTUALLY TOWARD MID WEEK WE
WILL BE IMPROVING AS WE START TO GET SOME RIDGING BUILD TOWARD THE
AREA.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
VFR THROUGH DUSK WITH INTERVALS OF MID/HIGH CLOUDS. SHOULD
DEVELOP SOME 5K CU FOR THIS AFTERNOON. GUSTS WILL PICK UP LATE
MORNING AND WILL BE AROUND 25 KNOTS TODAY...WITH A FEW 30 KNOT
GUSTS POSSIBLE. THE THE BULK OF THE SHOWERS/RAIN WILL BE
IMMEDIATELY BEHIND THE FRONT TO CROSS THE AREA LATE THIS AFTERNOON
AND EVENING. THERE IS SOME CHANCE OF A FEW ISOLATED SHRA/TS
DEVELOPING AHEAD OF THE FRONT WEST OF CLE/MFD IN PEAK
HEATING...BUT FOCUSED TAFS ON THE MORE WIDESPREAD CONDITIONS
BEHIND THE FRONT. WILL HAVE TO WATCH THE TIMING OF THE FRONT AS IT
APPEARS THAT IT WILL BE SLOWING AS IT MOVES EAST. DEFINITE
MVFR...WITH GOOD CHANCES OF IFR TOO. EMBEDDED THUNDER ALSO
POSSIBLE AT LEAST INITIALLY/EARLY. RAIN WILL TAKE MOST OF THE
NIGHT TO GET THROUGH CLE AND INTO SATURDAY MORNING FURTHER EAST.
WINDS TO COME AROUND TO THE NORTH OVERNIGHT.
.OUTLOOK...NON VFR LIKELY FRIDAY NIGHT INTO SATURDAY MORNING AND
AGAIN FOR THE EAST MONDAY INTO TUESDAY.
&&
.MARINE...
COLD FRONT TO COME ACROSS THE LAKE THIS EVENING. SOUTHERLY FLOW
ACROSS A STABLE LAKE WILL KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA
FOR TODAY. ENOUGH POST-FRONTAL WIND TO MAKE FOR A CHOPPY NEARSHORE
LATE TONIGHT THROUGH SATURDAY MORNING...AND A SMALL CRAFT ADV WILL
LIKELY BE NEEDED THEN. HIGH PRESSURE THEN SETTLES OVER THE NORTHERN
PLAINS/WESTERN LAKES INTO EARLY NEXT WEEK WHILE AN EAST COAST LOW
TRACKS TOWARD AND ACROSS NEW ENGLAND. THIS WILL AT LEAST TIGHTEN UP
THE GRADIENT AND WILL LIKELY HAVE ANOTHER PERIOD OF SMALL CRAFT
CONDITIONS FROM MONDAY INTO TUESDAY. NORTHERLY FLOW THIS WEEKEND AND
DEPENDING ON TRACK OF THE EAST COAST LOW...POSSIBLY BACKING TO
NORTHWEST FOR EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...ABE/KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
711 AM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD INTO THE AREA
SATURDAY NIGHT AND THEN WEAKEN SUNDAY. A SURFACE LOW AND UPPER LOW WILL
MOVE SOUTH TO NORTH OVER THE EASTERN UNITED STATES EARLY NEXT WEEK
AND THIS WILL AFFECT THE WEATHER ESPECIALLY OVER NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MADE MINOR ADJUSTMENTS TO THE SKY COVER GRIDS AND
TEMPERATURES. ANY THREAT OF SPRINKLES THE REMAINDER OF THE
MORNING WILL BE SMALL. OTHERWISE THE FORECAST SEEMS TO BE ON TARGET.
THE ISSUE FOR THIS AFTERNOON IS THE TIMING OF THE PRECIPITATION. THE
MODELS AND CURRENT CONDITIONS INDICATE THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE VERY CLOSE TO THE FRONT AND BEHIND IT. THE
FRONT IS EXPECTED TO BE FROM TOL TO FDY AROUND 20Z...CLE TO MFD AT
00Z AND ERI TO YNG BY 03Z. THE HRRR MODEL IS TRYING TO INDICATE SOME
SHOWERS DEVELOPING WAY AHEAD OF THE FRONT. MOST OF THE MODELS ARE
NOT INDICATING THIS...SO PLAYED THE FORECAST THAT WAY. SPC HAS SOME
OF THE AREA IN SEE TEXT FOR POSSIBLE SEVERE THUNDERSTORMS. EXPECTING
A FAIR AMOUNT OF CUMULUS CLOUDS THIS AFTERNOON...WE SHOULD HAVE SOME
SUNSHINE TO HELP INCREASE THE CAPES TOO MUCH. WILL MENTION IN THE HWO
STRONG TO AN ISOLATED SEVERE THUNDERSTORM COULD BE POSSIBLE. THE
BEST CHANCE FOR THUNDERSTORMS WILL BE WITHIN A FEW HOURS OF
FRONTAL PASSAGE. WITH THE SOUTHWEST FLOW AND SOME SUNSHINE WENT
TOWARD THE WARMEST GUIDANCE. ATTM WITH NOT 100% SUNSHINE WE SHOULD
NOT BREAK ANY RECORDS...THE RECORD HIGHS FOR TODAY ARE IN THE
LOWER TO MID 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
THE GFS/ECMWF HANG UNTO THE SHOWERS MUCH LONGER THAN THE OTHER
MODELS. THIS SEEMS REASONABLE WITH A FAIR AMOUNT OF OMEGA AND THE
UPPER TROF MOVING THROUGH TONIGHT AND SATURDAY. HIGH PRESSURE
RIDGE TRIES TO BUILD IN SATURDAY NIGHT AND WEAKEN BY SUNDAY...SO
SATURDAY NIGHT AND SUNDAY SHOULD BE DRY. MAY HAVE TO WORRY ABOUT
SOME FROST SATURDAY NIGHT IF THE WINDS DECREASE ENOUGH AND THE
CLOUDS COVER IS NOT TOO THICK. THE BEST CHANCE FOR DECREASING
CLOUDS WILL BE NORTHWEST OHIO. WITH SOME UNCERTAINTY DID NOT
MENTION FROST ATTM IN THE GRIDS/ZONES...ONLY THE HWO.
SUNDAY NIGHT THROUGH MONDAY NIGHT ARE INTERESTING WITH THE SURFACE LOW
AND UPPER LOW MOVING SOUTH TO NORTH OVER THE EASTERN UNITED
STATES. INTRODUCING CHANCE POPS OVER THE EASTERN PORTION OF THE
FORECAST AREA AND WITH THE AIR COLD ENOUGH A CHANCE OF RAIN OR
SNOW. NORTHWEST OHIO SHOULD REMAIN MAINLY DRY FROM THE
SYSTEM...THIS WILL HAVE TO BE WATCHED.
TENDED ON THE COOLER SIDE FOR THE TEMPERATURES.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A LOT OF UNCERTAINTY FROM TUESDAY ONWARD WITH THE FORECAST. TUESDAY
WILL DEPEND ON WHAT ENDS UP HAPPENING WITH THE EAST COAST LOW THAT
IS FORECAST TO CROSS NEW ENGLAND. HOW MUCH COLD/COOL AIR WILL BE
DRAWN SOUTHWARD WITH THIS. WITH A COUPLE RUNS WITH THIS GENERAL
SOLUTION HAVE LOWERED HIGH TEMPS ON TUESDAY AND WEDNESDAY AND THEY
WILL BE SITTING 5 TO 10 DEGREES BELOW NORMAL. THERE IS A LOT OF
SWING IN WHICH WAY THIS WILL TURN OUT. EVENTUALLY TOWARD MID WEEK WE
WILL BE IMPROVING AS WE START TO GET SOME RIDGING BUILD TOWARD THE
AREA.
&&
.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
VFR THROUGH DUSK WITH INTERVALS OF MID/HIGH CLOUDS. SHOULD
DEVELOP SOME 5K CU FOR THIS AFTERNOON. GUSTS WILL PICK UP LATE
MORNING AND WILL BE AROUND 25 KNOTS TODAY...WITH A FEW 30 KNOT
GUSTS POSSIBLE. THE THE BULK OF THE SHOWERS/RAIN WILL BE
IMMEDIATELY BEHIND THE FRONT TO CROSS THE AREA LATE THIS AFTERNOON
AND EVENING. THERE IS SOME CHANCE OF A FEW ISOLATED SHRA/TS
DEVELOPING AHEAD OF THE FRONT WEST OF CLE/MFD IN PEAK
HEATING...BUT FOCUSED TAFS ON THE MORE WIDESPREAD CONDITIONS
BEHIND THE FRONT. WILL HAVE TO WATCH THE TIMING OF THE FRONT AS IT
APPEARS THAT IT WILL BE SLOWING AS IT MOVES EAST. DEFINITE
MVFR...WITH GOOD CHANCES OF IFR TOO. EMBEDDED THUNDER ALSO
POSSIBLE AT LEAST INITIALLY/EARLY. RAIN WILL TAKE MOST OF THE
NIGHT TO GET THROUGH CLE AND INTO SATURDAY MORNING FURTHER EAST.
WINDS TO COME AROUND TO THE NORTH OVERNIGHT.
.OUTLOOK...NON VFR LIKELY FRIDAY NIGHT INTO SATURDAY MORNING AND
AGAIN FOR THE EAST MONDAY INTO TUESDAY.
&&
.MARINE...
COLD FRONT TO COME ACROSS THE LAKE THIS EVENING. SOUTHERLY FLOW
ACROSS A STABLE LAKE WILL KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA
FOR TODAY. ENOUGH POST-FRONTAL WIND TO MAKE FOR A CHOPPY NEARSHORE
LATE TONIGHT THROUGH SATURDAY MORNING...AND A SMALL CRAFT ADV WILL
LIKELY BE NEEDED THEN. HIGH PRESSURE THEN SETTLES OVER THE NORTHERN
PLAINS/WESTERN LAKES INTO EARLY NEXT WEEK WHILE AN EAST COAST LOW
TRACKS TOWARD AND ACROSS NEW ENGLAND. THIS WILL AT LEAST TIGHTEN UP
THE GRADIENT AND WILL LIKELY HAVE ANOTHER PERIOD OF SMALL CRAFT
CONDITIONS FROM MONDAY INTO TUESDAY. NORTHERLY FLOW THIS WEEKEND AND
DEPENDING ON TRACK OF THE EAST COAST LOW...POSSIBLY BACKING TO
NORTHWEST FOR EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
649 AM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD INTO THE AREA
SATURDAY NIGHT AND THEN WEAKEN SUNDAY. A SURFACE LOW AND UPPER LOW WILL
MOVE SOUTH TO NORTH OVER THE EASTERN UNITED STATES EARLY NEXT WEEK
AND THIS WILL AFFECT THE WEATHER ESPECIALLY OVER NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MADE MINOR ADJUSTMENTS TO THE SKY COVER GRIDS AND
TEMPERATURES. ANY THREAT OF SPRINKLES THE REMAINDER OF THE
MORNING WILL BE SMALL. OTHERWISE THE FORECAST SEEMS TO BE ON TARGET.
THE ISSUE FOR THIS AFTERNOON IS THE TIMING OF THE PRECIPITATION. THE
MODELS AND CURRENT CONDITIONS INDICATE THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE VERY CLOSE TO THE FRONT AND BEHIND IT. THE
FRONT IS EXPECTED TO BE FROM TOL TO FDY AROUND 20Z...CLE TO MFD AT
00Z AND ERI TO YNG BY 03Z. THE HRRR MODEL IS TRYING TO INDICATE SOME
SHOWERS DEVELOPING WAY AHEAD OF THE FRONT. MOST OF THE MODELS ARE
NOT INDICATING THIS...SO PLAYED THE FORECAST THAT WAY. SPC HAS SOME
OF THE AREA IN SEE TEXT FOR POSSIBLE SEVERE THUNDERSTORMS. EXPECTING
A FAIR AMOUNT OF CUMULUS CLOUDS THIS AFTERNOON...WE SHOULD HAVE SOME
SUNSHINE TO HELP INCREASE THE CAPES TOO MUCH. WILL MENTION IN THE HWO
STRONG TO AN ISOLATED SEVERE THUNDERSTORM COULD BE POSSIBLE. THE
BEST CHANCE FOR THUNDERSTORMS WILL BE WITHIN A FEW HOURS OF
FRONTAL PASSAGE. WITH THE SOUTHWEST FLOW AND SOME SUNSHINE WENT
TOWARD THE WARMEST GUIDANCE. ATTM WITH NOT 100% SUNSHINE WE SHOULD
NOT BREAK ANY RECORDS...THE RECORD HIGHS FOR TODAY ARE IN THE
LOWER TO MID 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
THE GFS/ECMWF HANG UNTO THE SHOWERS MUCH LONGER THAN THE OTHER
MODELS. THIS SEEMS REASONABLE WITH A FAIR AMOUNT OF OMEGA AND THE
UPPER TROF MOVING THROUGH TONIGHT AND SATURDAY. HIGH PRESSURE
RIDGE TRIES TO BUILD IN SATURDAY NIGHT AND WEAKEN BY SUNDAY...SO
SATURDAY NIGHT AND SUNDAY SHOULD BE DRY. MAY HAVE TO WORRY ABOUT
SOME FROST SATURDAY NIGHT IF THE WINDS DECREASE ENOUGH AND THE
CLOUDS COVER IS NOT TOO THICK. THE BEST CHANCE FOR DECREASING
CLOUDS WILL BE NORTHWEST OHIO. WITH SOME UNCERTAINTY DID NOT
MENTION FROST ATTM IN THE GRIDS/ZONES...ONLY THE HWO.
SUNDAY NIGHT THROUGH MONDAY NIGHT ARE INTERESTING WITH THE SURFACE LOW
AND UPPER LOW MOVING SOUTH TO NORTH OVER THE EASTERN UNITED
STATES. INTRODUCING CHANCE POPS OVER THE EASTERN PORTION OF THE
FORECAST AREA AND WITH THE AIR COLD ENOUGH A CHANCE OF RAIN OR
SNOW. NORTHWEST OHIO SHOULD REMAIN MAINLY DRY FROM THE
SYSTEM...THIS WILL HAVE TO BE WATCHED.
TENDED ON THE COOLER SIDE FOR THE TEMPERATURES.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A LOT OF UNCERTAINTY FROM TUESDAY ONWARD WITH THE FORECAST. TUESDAY
WILL DEPEND ON WHAT ENDS UP HAPPENING WITH THE EAST COAST LOW THAT
IS FORECAST TO CROSS NEW ENGLAND. HOW MUCH COLD/COOL AIR WILL BE
DRAWN SOUTHWARD WITH THIS. WITH A COUPLE RUNS WITH THIS GENERAL
SOLUTION HAVE LOWERED HIGH TEMPS ON TUESDAY AND WEDNESDAY AND THEY
WILL BE SITTING 5 TO 10 DEGREES BELOW NORMAL. THERE IS A LOT OF
SWING IN WHICH WAY THIS WILL TURN OUT. EVENTUALLY TOWARD MID WEEK WE
WILL BE IMPROVING AS WE START TO GET SOME RIDGING BUILD TOWARD THE
AREA.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR THROUGH THE FIRST HALF OF THE TAF WITH INTERVALS OF MID/HIGH
CLOUDS. SHOULD DEVELOP SOME 5K CU FOR THIS AFTERNOON. GUSTS WILL
PICK UP LATE MORNING AND WILL BE AROUND 25 KNOTS TODAY...WITH A
FEW 30 KNOT GUSTS POSSIBLE. THE THE BULK OF THE SHOWERS/RAIN WILL
BE IMMEDIATELY BEHIND THE FRONT TO CROSS THE AREA LATE THIS
AFTERNOON AND EVENING. THERE IS SOME CHANCE OF A FEW
ISOLATED/SCATTERED SHRA/TS DEVELOPING AHEAD OF THE FRONT WEST OF
CLE/MFD IN PEAK HEATING...BUT FOCUSED TAFS ON THE MORE WIDESPREAD
CONDITIONS BEHIND THE FRONT. DEFINITE MVFR...WITH GOOD CHANCES OF
IFR TOO. EMBEDDED THUNDER ALSO POSSIBLE AT LEAST INITIALLY/EARLY.
FRONT SLOWS WITH TIME AND RAIN WILL TAKE MOST OF THE NIGHT TO GET
THROUGH CLE AND INTO SATURDAY MORNING FURTHER EAST.
.OUTLOOK...NON VFR LIKELY FRIDAY NIGHT INTO SATURDAY MORNING AND
AGAIN FOR THE EAST MONDAY INTO TUESDAY.
&&
.MARINE...
COLD FRONT TO COME ACROSS THE LAKE THIS EVENING. SOUTHERLY FLOW
ACROSS A STABLE LAKE WILL KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA
FOR TODAY. ENOUGH POST-FRONTAL WIND TO MAKE FOR A CHOPPY NEARSHORE
LATE TONIGHT THROUGH SATURDAY MORNING...AND A SMALL CRAFT ADV WILL
LIKELY BE NEEDED THEN. HIGH PRESSURE THEN SETTLES OVER THE NORTHERN
PLAINS/WESTERN LAKES INTO EARLY NEXT WEEK WHILE AN EAST COAST LOW
TRACKS TOWARD AND ACROSS NEW ENGLAND. THIS WILL AT LEAST TIGHTEN UP
THE GRADIENT AND WILL LIKELY HAVE ANOTHER PERIOD OF SMALL CRAFT
CONDITIONS FROM MONDAY INTO TUESDAY. NORTHERLY FLOW THIS WEEKEND AND
DEPENDING ON TRACK OF THE EAST COAST LOW...POSSIBLY BACKING TO
NORTHWEST FOR EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
643 AM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD INTO THE AREA
SATURDAY NIGHT AND THEN WEAKEN SUNDAY. A SURFACE LOW AND UPPER LOW WILL
MOVE SOUTH TO NORTH OVER THE EASTERN UNITED STATES EARLY NEXT WEEK
AND THIS WILL AFFECT THE WEATHER ESPECIALLY OVER NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ONLY MADE MINOR ADJUSTMENTS TO THE SKY COVER GRIDS AND
TEMPERATURES. ANY THREAT OF SPRINKLES THE REMAINDER OF THE
MORNING WILL BE SMALL. OTHERWISE THE FORECAST SEEMS TO BE ON TARGET.
THE ISSUE FOR THIS AFTERNOON IS THE TIMING OF THE PRECIPITATION. THE
MODELS AND CURRENT CONDITIONS INDICATE THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE VERY CLOSE TO THE FRONT AND BEHIND IT. THE
FRONT IS EXPECTED TO BE FROM TOL TO FDY AROUND 20Z...CLE TO MFD AT
00Z AND ERI TO YNG BY 03Z. THE HRRR MODEL IS TRYING TO INDICATE SOME
SHOWERS DEVELOPING WAY AHEAD OF THE FRONT. MOST OF THE MODELS ARE
NOT INDICATING THIS...SO PLAYED THE FORECAST THAT WAY. SPC HAS SOME
OF THE AREA IN SEE TEXT FOR POSSIBLE SEVERE THUNDERSTORMS. EXPECTING
A FAIR AMOUNT OF CUMULUS CLOUDS THIS AFTERNOON...WE SHOULD HAVE SOME
SUNSHINE TO HELP INCREASE THE CAPES TOO MUCH. WILL MENTION IN THE HWO
STRONG TO AN ISOLATED SEVERE THUNDERSTORM COULD BE POSSIBLE. THE
BEST CHANCE FOR THUNDERSTORMS WILL BE WITHIN A FEW HOURS OF
FRONTAL PASSAGE. WITH THE SOUTHWEST FLOW AND SOME SUNSHINE WENT
TOWARD THE WARMEST GUIDANCE. ATTM WITH NOT 100% SUNSHINE WE SHOULD
NOT BREAK ANY RECORDS...THE RECORD HIGHS FOR TODAY ARE IN THE
LOWER TO MID 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
THE GFS/ECMWF HANG UNTO THE SHOWERS MUCH LONGER THAN THE OTHER
MODELS. THIS SEEMS REASONABLE WITH A FAIR AMOUNT OF OMEGA AND THE
UPPER TROF MOVING THROUGH TONIGHT AND SATURDAY. HIGH PRESSURE
RIDGE TRIES TO BUILD IN SATURDAY NIGHT AND WEAKEN BY SUNDAY...SO
SATURDAY NIGHT AND SUNDAY SHOULD BE DRY. MAY HAVE TO WORRY ABOUT
SOME FROST SATURDAY NIGHT IF THE WINDS DECREASE ENOUGH AS THE
CLOUDS WILL DECREASE.
SUNDAY NIGHT THROUGH MONDAY NIGHT ARE INTERESTING WITH THE SURFACE LOW
AND UPPER LOW MOVING SOUTH TO NORTH OVER THE EASTERN UNITED
STATES. INTRODUCING CHANCE POPS OVER THE EASTERN PORTION OF THE
FORECAST AREA AND WITH THE AIR COLD ENOUGH A CHANCE OF RAIN OR
SNOW. NORTHWEST OHIO SHOULD REMAIN MAINLY DRY FROM THE
SYSTEM...THIS WILL HAVE TO BE WATCHED.
TENDED ON THE COOLER SIDE FOR THE TEMPERATURES.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A LOT OF UNCERTAINTY FROM TUESDAY ONWARD WITH THE FORECAST. TUESDAY
WILL DEPEND ON WHAT ENDS UP HAPPENING WITH THE EAST COAST LOW THAT
IS FORECAST TO CROSS NEW ENGLAND. HOW MUCH COLD/COOL AIR WILL BE
DRAWN SOUTHWARD WITH THIS. WITH A COUPLE RUNS WITH THIS GENERAL
SOLUTION HAVE LOWERED HIGH TEMPS ON TUESDAY AND WEDNESDAY AND THEY
WILL BE SITTING 5 TO 10 DEGREES BELOW NORMAL. THERE IS A LOT OF
SWING IN WHICH WAY THIS WILL TURN OUT. EVENTUALLY TOWARD MID WEEK WE
WILL BE IMPROVING AS WE START TO GET SOME RIDGING BUILD TOWARD THE
AREA.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
VFR THROUGH THE FIRST HALF OF THE TAF WITH INTERVALS OF MID/HIGH
CLOUDS. SHOULD DEVELOP SOME 5K CU FOR THIS AFTERNOON. GUSTS WILL
PICK UP LATE MORNING AND WILL BE AROUND 25 KNOTS TODAY...WITH A
FEW 30 KNOT GUSTS POSSIBLE. THE THE BULK OF THE SHOWERS/RAIN WILL
BE IMMEDIATELY BEHIND THE FRONT TO CROSS THE AREA LATE THIS
AFTERNOON AND EVENING. THERE IS SOME CHANCE OF A FEW
ISOLATED/SCATTERED SHRA/TS DEVELOPING AHEAD OF THE FRONT WEST OF
CLE/MFD IN PEAK HEATING...BUT FOCUSED TAFS ON THE MORE WIDESPREAD
CONDITIONS BEHIND THE FRONT. DEFINITE MVFR...WITH GOOD CHANCES OF
IFR TOO. EMBEDDED THUNDER ALSO POSSIBLE AT LEAST INITIALLY/EARLY.
FRONT SLOWS WITH TIME AND RAIN WILL TAKE MOST OF THE NIGHT TO GET
THROUGH CLE AND INTO SATURDAY MORNING FURTHER EAST.
.OUTLOOK...NON VFR LIKELY FRIDAY NIGHT INTO SATURDAY MORNING AND
AGAIN FOR THE EAST MONDAY INTO TUESDAY.
&&
.MARINE...
COLD FRONT TO COME ACROSS THE LAKE THIS EVENING. SOUTHERLY FLOW
ACROSS A STABLE LAKE WILL KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA
FOR TODAY. ENOUGH POST-FRONTAL WIND TO MAKE FOR A CHOPPY NEARSHORE
LATE TONIGHT THROUGH SATURDAY MORNING...AND A SMALL CRAFT ADV WILL
LIKELY BE NEEDED THEN. HIGH PRESSURE THEN SETTLES OVER THE NORTHERN
PLAINS/WESTERN LAKES INTO EARLY NEXT WEEK WHILE AN EAST COAST LOW
TRACKS TOWARD AND ACROSS NEW ENGLAND. THIS WILL AT LEAST TIGHTEN UP
THE GRADIENT AND WILL LIKELY HAVE ANOTHER PERIOD OF SMALL CRAFT
CONDITIONS FROM MONDAY INTO TUESDAY. NORTHERLY FLOW THIS WEEKEND AND
DEPENDING ON TRACK OF THE EAST COAST LOW...POSSIBLY BACKING TO
NORTHWEST FOR EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1055 AM CDT FRI APR 20 2012
.DISCUSSION...
SURFACE WINDS HAVE ALREADY BEGUN TO SHIFT TO THE NORTH ACROSS THE
CWA...BUT THE TRUE COLD FRONT IS STRETCHED ACROSS CENTRAL TEXAS/HILL
COUNTRY. THE FRONT IS STILL EXPECTED TO REACH THE I-35 CORRIDOR
AT AROUND NOON. AS THE FRONTAL BOUNDARY APPROACHES...SFC PRESSURE
GRADIENTS WILL TIGHTEN LEADING TO WINDS INCREASING TO 15 TO 20 MPH
WITH GUSTS OF 25 TO 30 MPH. SCATTERED SHOWERS WILL CONTINUE THROUGH
THIS MORNING AHEAD OF THE FRONT...WITH A BROKEN LINE OF SHOWERS
AND THUNDERSTORMS ALONG THE FRONTAL BOUNDARY. HAVE EXTENDED POPS A
LITTLE FURTHER WEST AND SOUTHWEST GIVEN THE CURRENT DEVELOPMENT
ALONG THE TAIL-END OF THE FRONT. WINDS AND WIND GUSTS WERE ALSO
INCREASED THROUGH THIS EVENING PER 12Z NAM/15Z RUC SUGGESTIONS AND
16Z SFC OBS. OTHERWISE HAVE ONLY MADE MINOR ADJUSTMENTS TO ACCOUNT
FOR HOURLY TRENDS.
&&
.PREV DISCUSSION... /ISSUED 713 AM CDT FRI APR 20 2012/
AVIATION...
AT 12Z COLD FRONT EXTENDED FROM COMANCHE TO BROWNWOOD TO SONORA
MOVING SOUTHEAST. THE COLD FRONT WILL PUSH INTO THE HILL COUNTRY
BY LATE MORNING AND PUSH RAPIDLY SOUTH ALONG THE I-35 CORRIDOR BY
EARLY AFTERNOON. AN UPPER DISTURBANCE INTERACTING WITH THE FRONT
WILL PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
A FEW STORMS MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS
THIS AFTERNOON ALONG AND EAST OF THE I-35 CORRIDOR...INCLUDING THE
KSAT...KSSF AND KAUS TERMINALS. I-35 CORRIDOR TERMINALS MVFR AND
BRIEF IFR CIGS EARLY THIS MORNING BECOMING MVFR CIGS BY LATE
MORNING WITH SCTD SHOWERS LOCALLY LOWERING VSBYS. LOW VFR CIGS
BY LATE MORNING WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING LATE MORNING THROUGH MID AFTERNOON LOCALLY LOWERING
CIGS AND VSBYS. DECREASING CLOUDS LATE AFTERNOON BECOMING MOSTLY
CLEAR BY EVENING. I-35 CORRIDOR WINDS LIGHT AND VARIABLE TO LIGHT
SOUTHEAST TO EAST BECOMING NORTH 15 TO 20 KTS BY LATE MORNING.
NORTH WINDS LOWERING TO AROUND 10 KTS BY MIDNIGHT. KDRT TERMINAL
VARIABLE VFR CLOUDS BECOMING CLEAR THIS EVENING. EAST WIND 5 TO 10
KTS BECOMING NORTHWEST NEAR 15 KTS BY LATE MORNING. KDRT WINDS
BECOMING LIGHT NORTHEAST BY DARK.
PREV DISCUSSION... /ISSUED 347 AM CDT FRI APR 20 2012/
DISCUSSION...
AT 08Z THE COLD FRONT EXTENDED FROM PECOS TO SAN ANGELO TO SHERMAN
MOVING SOUTHEASTWARD. THE FRONT WILL ENTER THE HILL COUNTRY AROUND
9 AM AND WILL BE LOCATED ALONG THE I-35 CORRIDOR AROUND NOONTIME.
ISOLATED WARM SECTOR SHOWERS WILL OCCUR THIS MORNING UNDER THE CAP
IN ADVANCE OF THE FROPA AND LAGGING UPPER LEVEL TROF. THE SPC DAY
ONE CONVECTIVE OUTLOOK HAS OUR CWFA IN THE SLIGHT RISK AREA ALONG
AND EAST OF A LINE FROM LEXINGTON TO SAN MARCOS TO SAN ANTONIO TO
DILLEY AND WE AGREE WITH THIS DELINEATION. CONVECTION ALONG AND
BEHIND THE SHALLOW FRONTAL BOUNDARY WILL INCREASE AS THE SFC
FRONT NEARS THE I-35 CORRIDOR. THE PRIMARY SEVERE WEATHER THREATS
WILL BE LARGE HAIL AND DAMAGING WINDS ASSOCIATED WITH ACCELERATING
BOW SEGMENTS. THE SAN ANTONIO AND AUSTIN METRO AREAS ARE ON THE
WESTERN EDGE OF THE SLIGHT RISK AREA WHERE THE SEVERE STORMS MAY
FIRST INITIATE. THE CONVECTIVE COMPLEX WILL EXIT OUR SOUTHEAST
COUNTIES AROUND MIDNIGHT. HIGHS THIS AFTERNOON WILL RANGE FROM THE
MID 70S ACROSS OUR NORTHEAST COUNTIES TO UPPER 80S SOUTHWEST.
A DRY AIRMASS WILL OVERSPREAD SOUTH CENTRAL TEXAS IN THE WAKE OF
TODAYS FROPA. THIS WILL RESULT IN COOL NIGHTS FOLLOWED BY MILD
AFTERNOONS OVER THE WEEKEND. OVERNIGHT LOWS WILL FALL INTO THE
MID TO UPPER 40S ACROSS THE HILL COUNTRY. AFTERNOON HIGHS WILL BE
AROUND SEASONAL NORMALS.
A DRY NORTHWEST FLOW ALOFT WILL PREVAIL THRU THE MIDDLE OF NEXT
WEEK KEEPING SOUTH CENTRAL TEXAS RAIN FREE. THE UPPER LEVEL RIDGE
AXIS OVER NORTHERN MEXICO/SOUTHWESTERN U.S. WILL SHIFT EASTWARD
INTO TEXAS BY THE END OF NEXT WEEK. LOW LEVEL MOISTURE WILL BEGIN
TO RETURN TO SOUTH CENTRAL TEXAS TUESDAY NIGHT INTO WEDNESDAY
MORNING AS THE SFC HIGH MOVES OVER THE NORTHERN GULF OF MEXICO.
PATCHY MORNING FOG WILL BE POSSIBLE SOUTH AND EAST OF THE I-35
CORRIDOR WEDNESDAY MORNING AS THE AIRMASS BEGINS ITS TRANSITION
FROM CONTINENTAL TO GULF/MARITIME.
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE SATURDAY AFTERNOON
ACROSS THE EDWARDS PLATEAU AND RIO GRANDE PLAINS DUE TO LOW
RELATIVE HUMIDITIES. MINIMUM AFTERNOON RELATIVE HUMIDITIES WILL
FALL BELOW 25 PERCENT WEST OF A LINE FROM MOUNTAIN HOME TO HONDO
TO COTULLA WITH AROUND 20 PERCENT EXPECTED ALONG THE RIO GRANDE.
20-FOOT WINDS WILL BE NORTHERLY AT 5 TO 10 MPH.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 76 53 76 53 83 / 50 10 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 75 50 76 48 82 / 50 10 0 0 0
NEW BRAUNFELS MUNI AIRPORT 78 53 78 49 82 / 40 10 0 0 0
BURNET MUNI AIRPORT 74 49 75 48 81 / 40 - 0 0 0
DEL RIO INTL AIRPORT 86 55 83 54 87 / 10 - 0 0 0
GEORGETOWN MUNI AIRPORT 75 47 75 47 81 / 50 10 0 0 0
HONDO MUNI AIRPORT 82 50 80 48 84 / 30 - 0 0 0
SAN MARCOS MUNI AIRPORT 76 52 77 49 82 / 40 10 0 0 0
LA GRANGE - FAYETTE REGIONAL 76 54 75 53 80 / 60 10 0 0 0
SAN ANTONIO INTL AIRPORT 79 53 78 52 82 / 30 10 0 0 0
STINSON MUNI AIRPORT 80 55 79 53 83 / 30 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...01
SYNOPTIC/GRIDS...25
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
627 AM CDT FRI APR 20 2012
.DISCUSSION...UPDATED FOR 12Z AVIATION.
&&
.AVIATION...CLOUDS WILL BEGIN TO BUILD IN THIS MORNING AHEAD OF AN
APPROACHING COLD FRONT. THIS FRONT WILL PUSH THROUGH THE TAF SITES
THIS AFTERNOON WITH THUNDERSTORM CHANCES JUST AHEAD OF AND ALONG
THE FRONT. SOME STORMS...ESPECIALLY FOR EASTERN SITES MAY BE
SEVERE THIS EVENING. GUSTY NORTHERLY WINDS ARE EXPECTED TO DEVELOP
BEHIND THE FRONT AND LINGER OVERNIGHT. VFR CONDITIONS WILL RETURN
FOR SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 416 AM CDT FRI APR 20 2012/
SHORT TERM (TODAY THROUGH SATURDAY)...MAIN FORECAST CONCERN IS
WITH THUNDER AND SEVERE POTENTIAL TODAY. SURFACE LOW CURRENTLY
OVER NORTHERN ILLINOIS WITH COLD FRONT DRAPED INTO WEST TEXAS
WILL PROGRESS EASTWARD TODAY. AHEAD OF THE FRONT SOUTH TO
SOUTHEAST SURFACE WINDS AND SOUTH TO SOUTHWEST WINDS AT H850 WILL
ALLOW FOR GOOD HEATING TODAY. H850 WINDS WILL ALSO KEEP A PRETTY
STRONG CAP IN PLACE FOR MUCH OF THE DAY...HAMPERING PRECIPITATION.
ANYTHING THAT WOULD DEVELOP THIS MORNING AND EARLY AFTERNOON
SHOULD JUST REMAIN SHOWER ACTIVITY. THE FRONT MOVES IN BY MID
AFTERNOON WIPING OUT THE CAP AND BRINGING A BRIEF WINDOW FOR
SEVERE WEATHER POTENTIAL. MOST MODELS ARE PEAKING CAPE ACROSS THE
AREA AROUND 1500-2000 J/KG THIS AFTERNOON...ALTHOUGH THE RUC AND
SOME MESO MODELS ARE A BIT HIGHER THAN THIS...ESPECIALLY EAST.
CONSENSUS FOR CONVECTIVE INITIATION SEEMS TO BE IN THE 20-21Z TIME
FRAME ALONG THE COLD FRONT WHERE CIN RAPIDLY DECREASES. LAPSE
700-500 LAPSE RATES LOOK FAVORABLE AND LI VALUES DECREASE TO AS
MUCH AS -8 DEPENDING ON THE MODEL. THE BIGGEST DETERRENT THOUGH MAY
BE THE SOUTHWESTERLY 850 MB WINDS. THIS COULD POTENTIALLY MAKE THE
CAP STRONG ENOUGH TO NOT ERODE BEFORE THE UPPER TROUGH MOVES
THROUGH...AND IT COULD ALSO BRING TOO MUCH DRY AIR IN...DEPENDING
ON THE DEPTH OF THESE SOUTHWEST WINDS. ADDITIONALLY...PWAT VALUES
ARE LESS THAN IMPRESSIVE FOR THE ENTIRE AREA...WITH MAINLY 1 TO
1.5 INCH VALUES EXPECTED.
WHILE THE ENTIRE FORECAST AREA HAS THE CHANCE TO SEE SEVERE
WEATHER...MAINLY A WIND AND HAIL THREAT...THE BEST CHANCE WILL BE
IN THE NORTHEAST PORTION OF THE FORECAST AREA...AND BETWEEN 21 AND
00Z.
THE UPPER TROUGH HANGS BACK A BIT, BUT SHOULD STILL MOVE
THROUGH BETWEEN 00 AND 06Z QUICKLY ENDING PRECIP CHANCES ACROSS
THE AREA. ONCE THE UPPER TROUGH GETS OUT OF HERE PLEASANT...BUT
BREEZY CONDITIONS WILL FILTER IN. TEMPERATURES SHOULD COOL NICELY
OVERNIGHT FRIDAY NIGHT INTO SATURDAY MORNING WITH TEMPS DECREASING
INTO THE 50S FOR MUCH OF THE AREA. SATURDAY LOOKS TO WARM BACK
INTO THE UPPER 70S AND 80S...BUT WITH MUCH LOWER DEWPOINTS.
MARINE...BEHIND THE COLD FRONT FRIDAY NIGHT STRONG OFFSHORE FLOW
WILL DEVELOP. WITH WARM SURFACE WATER TEMPERATURES GUSTS SHOULD
MIX DOWN PRETTY EASILY. THIS WILL LIKELY BRING NEAR GALE FORCE
GUSTS TO THE AREA BETWEEN 06Z AND 18Z SATURDAY. WILL HOLD OFF ON
ISSUING A GALE WATCH AT THIS TIME...BUT ONE MAY BE NEEDED LATER
TODAY. AT LEAST A SMALL CRAFT ADVISORY IS LIKELY.
LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)...UPPER LEVEL TROUGH WILL
BE EAST OF THE AREA TO START THE EXTENDED PART OF THE FORECAST.
DRIER AIR WILL BE ENTRENCHED OVER SOUTH TEXAS AS PRECIPITABLE WATER
VALUES FALL BELOW 0.75 INCHES. WITH WINDS BECOMING LIGHTER INLAND
AND THE DRY AIR...ANTICIPATE DECENT RADIATIONAL COOLING SATURDAY
NIGHT WITH TEMPS FALLING INTO THE LOWER/MID 50S ACROSS MUCH OF THE
REGION. A DRY NORTHWEST FLOW ALOFT WILL PREVAIL INTO EARLY NEXT WEEK
AS UPPER LEVEL RIDGE BECOMES ESTABLISHED ACROSS THE ROCKIES. SURFACE
HIGH WILL SHIFT TO THE EAST ON TUESDAY WITH ONSHORE FLOW RETURNING.
TEMPS WILL MODERATE THROUGH THE WEEK...WITH LOWER 90S ACROSS THE
WEST TO LOWER/MID 80S NEAR THE COAST WEDNESDAY THROUGH FRIDAY.
LATEST RUN OF THE GFS BREAKS THE UPPER RIDGE DOWN ON THURSDAY BUT
THE EURO KEEPS UPPER TROUGH OUT WEST THROUGH THE PERIOD. FORECAST
WILL CONTINUE TO FAVOR AMPLIFIED UPPER RIDGE SOLUTION FOR THE TIME
BEING. NO SIGNIFICANT CHANGES MADE TO THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 81 58 78 53 82 / 40 30 0 0 0
VICTORIA 80 54 76 50 79 / 50 30 0 0 0
LAREDO 90 63 85 58 89 / 20 10 0 0 0
ALICE 85 55 81 52 83 / 30 20 0 0 0
ROCKPORT 79 60 79 57 78 / 40 40 0 0 0
COTULLA 87 55 82 50 85 / 20 10 0 0 0
KINGSVILLE 83 58 79 52 83 / 40 30 0 0 0
NAVY CORPUS 79 62 78 61 78 / 40 40 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
PZ/83...SHORT TERM
TB/78...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
626 AM CDT FRI APR 20 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
333 AM CDT FRI APR 20 2012
MAIN FORECAST CONCERNS ARE ON FROST/FREEZE TONIGHT AND NEXT EXPECTED
RAIN SATURDAY/SATURDAY NIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING BUILDING UP OVER THE WESTERN U.S....TROUGHING FROM
MINNESOTA SOUTH INTO TEXAS...AND RIDGING ALONG THE EAST COAST OF THE
U.S. WITHIN THE TROUGHING...MAIN FEATURES OF NOTE INCLUDE SHORTWAVES
OVER THE EASTERN SIDE OF THE FORECAST AREA AND BACK OVER WESTERN
SOUTH DAKOTA INTO NORTHWEST NEBRASKA. THE LATTER SHORTWAVE HAS
HELPED PUSH THE LOW TO MID LEVEL FRONTOGENESIS ZONE AND DEEP
MOISTURE SEEN ON THE 00Z GRB SOUNDING EASTWARD. REGARDING THAT
FRONTOGENESIS ZONE...THIS IS EASILY SEEN IN 00Z RAOBS AT 850MB WITH
0C AT MPX...3C AT GRB AND 12C AT DVN. IN ADDITION...AN UPPER JET
STREAK OF 100-110 KT IN EASTERN ONTARIO LAST EVENING...AIDING IN
FORCING FOR PRECIPITATION ACROSS WISCONSIN...HAS BEEN PUSHED
EASTWARD BY THE SHORTWAVE. LATEST RADAR MOSAIC SHOWS JUST A LITTLE
LIGHT RAIN/SNOW IN A WEAKENING COLD CONVEYOR BELT IN CENTRAL
WISCONSIN. TO THE WEST...SUBSIDENCE AND DRYING HAS BEEN CLEARING
SKIES OUT ACROSS MINNESOTA. A SURFACE RIDGE OF HIGH PRESSURE HAS
ALSO BEEN DROPPING SOUTH INTO THE DAKOTAS AND WESTERN MINNESOTA.
FARTHER WEST...A FEW SHOWERS CONTINUE BACK OVER CENTRAL SOUTH
DAKOTA AHEAD OF THE SHORTWAVE THERE. LAST ITEM OF NOTE IS A
SHORTWAVE ON WATER VAPOR COMING INTO SOUTHERN BRITISH COLUMBIA.
TODAY AND TONIGHT...UPPER TROUGHING OVER MINNESOTA WILL SLIDE EAST
ACROSS THE THE FORECAST AREA TODAY...ALLOWING THE SURFACE RIDGE OF
HIGH PRESSURE TO BUILD INTO THE FORECAST AREA THIS EVENING. THIS
SHOULD ALLOW FOR CLEARING AND DRYING. TEMPERATURES ARE LIKELY TO NOT
END UP MUCH HIGHER THAN YESTERDAY BECAUSE 850MB TEMPS ARE -2 TO
-3C...BUT MORE SUN AND THE LACK OF RAIN WILL MAKE IT FEEL WARMER.
QUESTION TONIGHT IS FROST/FREEZE. HAVING THE SURFACE RIDGE OVER
THE AREA IN THE EVENING IS GOOD FOR GETTING COLD...BUT THERE IS AN
ISSUE LURKING UPSTREAM. THE SHORTWAVE COMING INTO SOUTHERN BRITISH
COLUMBIA MODELS SHOW TOPPING THE WESTERN U.S. RIDGE TODAY...THEN
DROPPING INTO THE EASTERN DAKOTAS BY 12Z SATURDAY. ANTICIPATING A
STREAM OF MID AND HIGH LEVEL CLOUD COVER TO SPREAD DOWNSTREAM
AHEAD OF THIS SHORTWAVE...MOVING INTO THE FORECAST AREA AFTER
MIDNIGHT. IT APPEARS LOCATIONS ACROSS SOUTHWEST INTO CENTRAL
WISCONSIN WILL STAY THE CLEAREST THE LONGEST...AND THE SURFACE
RIDGE IS EXPECTED TO STAY IN PLACE THERE TOO. THEREFORE... FEEL
THIS AREA HAS THE BEST POTENTIAL FOR FREEZE CONDITIONS WITH
AREAS/WIDESPREAD FROST. FREEZE WARNINGS NOTED IN THE WWA SECTION
BELOW. ANOTHER POTENTIAL ISSUE TO CONTEND WITH MIGHT BE FOG GIVEN
RECENT RAINS. NOT VERY CONFIDENT TO INCLUDE FOG AT THIS TIME...
EITHER FOR RADIATIONAL INDUCED OR IN THE VALLEYS...AS THERE SHOULD
BE DECENT DRYING TODAY.
SATURDAY AND SATURDAY NIGHT...SHORTWAVE OVER THE EASTERN DAKOTAS
LOOKS TO CONTINUE ITS SOUTHEASTWARD TREK DOWN THE UPPER RIDGE. THE
20.00Z NAM IS AN OUTLIER WITH ITS TRACK...MOVING INTO WISCONSIN
TONIGHT. THE 20.00Z GFS/UKMET/ECMWF ALL TAKE A FARTHER WEST TRACK
THROUGH SOUTHEAST MINNESOTA AND NORTHEAST IOWA TONIGHT WHICH SEEMS
MORE REASONABLE. ISENTROPIC LIFT ASSOCIATED WITH THE SHORTWAVE...
BEST SEEN ON 290-300K SURFACES...WILL MOVE INTO SOUTHEAST MINNESOTA
AND NORTHEAST IOWA ON SATURDAY. SHOULD EVENTUALLY SEE RAIN DEVELOP
AS LOW LEVELS MOISTEN. AFTERNOON SEEMS MOST LIKELY TO SEE RAIN.
ANOTHER FAVORABLE FORCING MECHANISM IS A 120KT UPPER JET DROPPING
DOWN INTO SOUTHWEST MINNESOTA...PLACING LOCATIONS WEST OF THE
MISSISSIPPI RIVER IN UPPER DIVERGENCE. NICE LOW TO MID LEVEL
FRONTOGENESIS/FRONTOLYSIS COUPLET SHOWS UP TOO. BOTH THE ISENTROPIC
LIFT AND UPPER JET FORCING DIMINISHES SATURDAY NIGHT...WHICH WOULD
SUGGEST PRECIPITATION SHOULD DIMINISH. THE LOW TO MID LEVEL
FRONTOGENESIS LINGERS...THOUGH...NOTED TOO BY AN INVERTED TROUGH AT
THE SURFACE LINGERING BACK INTO WESTERN MINNESOTA. THEREFORE...
SHOULD STILL SEE SOME LIGHT PRECIPITATION AFTER MIDNIGHT. GIVEN THE
STRONG FORCING SIGNALS...HAVE RAISED PRECIPITATION CHANCES
UP...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. PRECIPITABLE WATER
VALUES ARE NOT THAT IMPRESSIVE...0.5-0.6 INCHES...WHICH MEANS WE
SHOULD NOT SEE MUCH QPF. ONLY CONCERN THAT EXISTS IS THE
PRECIPITATION COULD SHIFT WESTWARD OVER THE NEXT 24-48 HOURS SEEING
MODEL TRENDS. WITH PLENTY OF CLOUDS SPREADING IN SATURDAY MORNING
AND 850MB TEMPS OF 0 TO -2C ON SATURDAY...ANTICIPATING COOL
TEMPERATURES. ONLY 5 TO 10 DEGREES OF COOLING EXPECTED SATURDAY
NIGHT THANKS TO CLOUDS REMAINING IN PLACE.
SUNDAY AND SUNDAY NIGHT...20.00Z GFS/NAM/UKMET/ECMWF/CANADIAN ALL
SHOW ANOTHER SHORTWAVE DROPPING DOWN THE EAST SIDE OF THE WESTERN
U.S. RIDGE. AGAIN...THE MODELS DIFFER WITH THE TRACK...UKMET
FARTHEST WEST NEAR I-35 WITH THE NAM FARTHEST EAST OVER SOUTHWEST
WISCONSIN. IN ANY EVENT...THIS SHORTWAVE COMES THROUGH DURING THE
DAYTIME HOURS. WITH THAT INVERTED SURFACE TROUGH IN PLACE AND
DAYTIME HEATING...SHOULD SEE SOME ISOLATED/SCATTERED SHOWERS
DEVELOP. IF THERE IS ANYTHING GOING AGAINST PRECIPITATION IS A
NORTHEAST TO SOUTHWEST ORIENTED SURFACE RIDGE PROGGED TO BUILD INTO
THE AREA DURING THE AFTERNOON. A DRYING NORTHEAST FLOW COULD LIMIT
SOME OF THE AREAL COVERAGE OF PRECIPITATION...AS SUGGESTED IN 20.00Z
GFS OUTPUT. THEREFORE...FOR NOW CHANCES ARE ONLY 20-30. THE DRYING
FLOW PLUS DAYTIME MIXING SHOULD ALLOW FOR SOME DECREASE IN
CLOUDS...THOUGH A BETTER SHOT OF CLEARING SHOULD COME SUNDAY NIGHT
WITH SUBSIDENCE IN THE WAKE OF THE SHORTWAVE. REGARDING
TEMPERATURES...850MB READINGS ON SUNDAY ARE SIMILAR TO SATURDAY...0
TO -2C. WITH OVERALL LIMITED SUN...ANTICIPATE ANOTHER RELATIVELY
COOL DAY WITH HIGHS IN THE 50S. IF MORE SUN OCCURS THAN
EXPECTED...READINGS MAY GET INTO THE 60S. WITH CLEARING SUNDAY NIGHT
AND THE RIDGE SETTLING IN...COULD SEE YET ANOTHER FROST/FREEZE
NIGHT...ESPECIALLY FOR SOUTHWEST AND CENTRAL WISCONSIN.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
333 AM CDT FRI APR 20 2012
DIFFICULT LONG TERM FORECAST...ESPECIALLY GETTING INTO THE MIDDLE OF
NEXT WEEK WHERE MODELS ARE ALL OVER THE PLACE WITH THE HANDLING OF
THE UPPER LEVEL PATTERN OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THROUGH ABOUT TUESDAY...MODELS ARE IN GOOD AGREEMENT
MAINTAINING WESTERN RIDGING AND TROUGHING OVER THE EAST COAST OF THE
U.S.. 500MB HEIGHTS DO RISE MONDAY THROUGH TUESDAY WHICH WILL HELP
TO BRING WARMER AIR INTO THE FORECAST AREA. BY 00Z WEDNESDAY...850MB
TEMPS CLIMB TO 4-8C...IF NOT A LITTLE HIGHER. STILL HAVING TO
MAINTAIN SOME CHANCES OF PRECIPITATION TUESDAY NIGHT...DUE TO A
SHORTWAVE PROGGED TO COME THROUGH THE NORTHWEST FLOW. 20.00Z
ECMWF/GEM ARE PRETTY ACTIVE WITH THIS SHORTWAVE TOO...RESULTING FROM
FAVORABLE DYNAMICAL FORCING. WHAT HAPPENS IN THE WAKE OF THIS
FEATURE IS ANYONES GUESS RIGHT NOW. THE 20.00Z ECMWF IS STUCK WITH
TROUGHING FROM HUDSON BAY DOWN INTO THE EASTERN GREAT LAKES...
MAINTAIN A COOL NORTHWEST FLOW. WOULD PROBABLY END UP WITH
PERIODIC RAIN SHOWERS WITH SHORTWAVES MOVING THROUGH IN THE ECMWF
SCENARIO. ON THE OTHER HAND...THE 20.00Z GFS/GFS ENSEMBLES SAY
WEDNESDAY THROUGH THURSDAY THE WESTERN RIDGE TRIES TO BUILD
TOWARDS THE AREA...BEING PUSHED MORE BY TROUGHING COMING INTO THE
WEST COAST. IF THIS HAPPENS...PERIODIC SHOWER AND THUNDERSTORMS
CHANCES WOULD RESULT AS A WARM FRONT APPROACHES THE REGION. THE
SOLUTIONS ALSO ARE MUCH WARMER THAN THE ECMWF. FOR NOW...HAVE
SPLIT THE DIFFERENCE BETWEEN THE TWO SOLUTIONS. NEEDLESS TO
SAY...CONFIDENCE ON THE PRECIPITATION AND TEMPERATURE FORECASTS IS
LOW.
&&
.AVIATION...TODAY INTO SATURDAY
626 AM CDT FRI APR 20 2012
SYSTEM RESPONSIBLE FOR THE MVFR/IFR CONDITIONS/RAIN THU AFTERNOON/
EVENING WILL MOVE EAST/SOUTH OF THE TAF SITES THIS MORNING WITH GOOD
VFR EXPECTED AT BOTH SITES BY 15Z. WITH THE RECENT RAINS AND COOLER
HIGH PRESSURE BUILDING INTO THE AREA AND DEEP MIXING/STEEP SFC TO
850-800MB LAPSE RATES FOR THE AFTERNOON...FEW-SCT VFR CUMULUS
EXPECTED THRU THE AFTERNOON. THE DEEP MIXING WILL ALLOW FOR SOME
18-22KT WIND GUSTS AS WELL DURING THE AFTERNOON HOURS. WINDS QUICKLY
DIMINISH THIS EVENING AS THE BOUNDARY LAYER COOLS AND SFC RIDGE AXIS
BUILDING INTO THE AREA. SFC RIDGE AXIS MOVES QUICKLY ACROSS THE
AREA...WITH ONLY A BRIEF PERIOD OF LIGHT/VARIABLE OR CALM WINDS
EXPECTED. WITH WINDS RATHER QUICKLY BECOMING SOUTHEAST LATE
TONIGHT...THIS WILL LIMIT THE THREAT OF BR/FG AT BOTH KRST/KLSE LATE
TONIGHT/EARLY SAT MORNING. MID/HIGH LEVEL MOISTURE AHEAD OF THE NEXT
LOW/SHORTWAVE SPREADS INTO THE AREA LATE TONIGHT/SAT MORNING. BULK
OF THIS AT OR ABOVE 600MB /12K FT/ THRU 12Z SAT. MOISTURE INCREASES/
LOWERS THRU THE DAY SAT AS THE NEXT LOW/SHORTWAVE MOVE EAST INTO THE
REGION...WITH SCT -SHRA IN/AROUND THE AREA BY SAT AFTERNOON. CIGS/
VSBYS EXPECTED TO REMAIN VFR THRU MID-DAY SAT...WITH SCT MVFR
CIGS/VSBYS IN -SHRA SAT AFTERNOON.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
333 AM CDT FRI APR 20 2012
WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR
WIZ017-029-034-042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION.....RRS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1005 AM MDT FRI APR 20 2012
.UPDATE...
&&
.SHORT TERM...SKIES HAVE CLEARED OUT NICELY OVER THE NORTHEAST
PLAINS THIS MORNING...WHILE CONSIDERABLE AMOUNT OF MOISTURE
REMAINS TRAPPED IN THE MOUNTAINS. WILL ADJUST CLOUD COVER TO
ACCOUNT FOR CLOUD TRENDS TODAY BUT SHOULD SEE SOME PARTIAL
CLEARING IN THE MOUNTAINS THIS AFTERNOON. OTHERWISE NO OTHER
ISSUES FOR TODAY.
.AVIATION...NO ISSUES TODAY WITH MOSTLY CLEAR SKIES WITH JUST A
FEW CUMULUS AROUND. SURFACE WINDS GENERALLY UNDER 12KT TODAY AND
CURRENTLY ARE SOUTHEAST AND SHOULD TREND TO THE EAST AND
NORTHEAST THIS AFTERNOON. THERE MAY BE SOME NW WINDS MIXING OUT
IN/NEAR THE FOOTHILLS BY LATE AFTERNOON BUT A BIT UNCLEAR IF THIS
WILL MAKE IT AS FAR EAST AS DEN/APA.
&&
.PREV DISCUSSION... /ISSUED 319 AM MDT FRI APR 20 2012/
SHORT TERM...INCREASING MID LEVEL QG DESCENT WILL BE OVER THE
CWFA THIS MORNING AS THE UPPER LEVEL JET SHIFTS TO THE EAST.
LINGERING SHOWERS OVER THE NORTHEAST PLAINS THIS MORNING ARE JET
INDUCED. THE HRRR AND RUC13 MDLS KILL OFF THE SHOWERS IN THE
12-15Z TIME FRAME SO WILL TREND THE FCST THAT WAY AS WELL. SOME
STRATUS HAS DEVELOPED AROUND THE DENVER AREA THIS MORNING
FOLLOWING THE FRONTAL PASSAGE. NOT MUCH IMMEDIATELY UPSTREAM SO DO
NOT EXPECT THE STRATUS TO LINGER FOR VERY LONG...SHUD SEE THE LOW
CLOUD LAYER START TO DECREASE AFTER 12Z. THERE WILL BE SOME
CLEARING LATER THIS MORNING BUT ENUF WEAK INSTBY THIS AFTERNOON
FOR CONVECTIVE CLOUD COVER TO REDEVELOP. WL GO WITH PRIMARILY
PARTLY CLOUDY FCST TODAY. SPATIAL CROSS-SECTIONS AND SIMULATED
STLT PRODUCTS APPEAR TO SUPPORT THIS THROUGH EARLY THIS EVENING.
CLEARING OVERNIGHT EXPECTED WITH SOME OCCASIONSL GUSTY DOWNSLOPE
WINDS ALONG THE FRONT RANGE FOOTHILLS OVERNIGHT
LONG TERM...AN UPPER LEVEL RIDGE WILL BE OVER THE AREA THRU THE
WEEKEND. THIS WILL LEAD TO MAINLY DRY CONDITIONS WITH ABV NORMAL
TEMPS. SOME MOISTURE MAY MOVE INTO THE MTNS ON SUN SO WILL MENTION
SOME ISOLD LATE AFTN/EVENING TSTMS OVER THE HIGHER TERRAIN. HIGHS
BOTH DAYS OVER NERN CO WILL BE IN THE 70S.
THE UPPER LEVEL RIDGE WILL REMAIN OVER THE AREA MON AND TUE
WITH CROSS-SECTIONS SHOWING LIMITED MOISTURE. ONCE AGAIN COULD SEE
SOME ISOLD CONVECTION OVER THE HIGHER TERRAIN IN THE LATE
AFTN/EARLY EVENING HOURS. HIGHS WILL REMAIN ABV NORMAL BOTH DAYS WITH
HIGHS POSSIBLY REACHING THE LOWER TO MID 80S ACROSS NERN CO BY
TUE.
FOR WED AND THU THERE IS NOT MUCH AGREEMENT BETWEEN THE ECMWF AND
THE GFS. THE ECMWF KEEPS A FLAT RIDGE OVER THE AREA WHILE THE GFS
SHOWS AN UPPER LEVEL LOW MOVING ACROSS SRN CO LATE WED INTO THU.
THE CANADIAN MODEL IS MORE IN LINE WITH THE ECMWF SO WILL TREND
FCST MORE TOWARDS THE ECMWF. THE ECMWF SHOWS A WK FNT MAY MOVE
INTO NERN CO ON WED WITH SOME INCREASE IN MOISTURE AS A WK
DISTURBANCE TRACKS ACROSS NRN CO BY WED AFTN OR NIGHT. THUS COULD
SEE AT LEAST A SLIGHT CHC OF AFTN/EVENING CONVECTION OVER NRN CO.
TEMPS ON WED MAY COOL DOWN BACK DOWN INTO THE 70S ACROSS NERN CO
BEHIND WK FNT. ON THU THE ECMWF STILL SHOWS ENOUGH MOISTURE AROUND
FOR A SLIGHT CHC OF AFN/EVENING CONVECTION OVER NRN CO WITH LITTLE
CHANGE TO TEMPS.
AVIATION...IFR/MVFR CIGS AROUND DENVER SHOULD START TO LIFT BY
12Z WITH VFR CONDITIONS AFTER 15Z. NORTHERLY WINDS THIS MORNING
WILL DECREASE AND BECOME MORE VARIABLE BY 15Z. AFTER 18Z WILL KEEP
THE MENTION OF AN E-SELY WIND IN THE TAFS FOR KDEN AND KAPA...
WITH A WEAK W-NWLY OR VRBL SFC WIND AT KBJC.
HYDROLOGY...NO PRECIPITATION IS EXPECTED FOR THE FOUR MILE
CANYON AREA TODAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...ENTREKIN
LONG TERM....RPK
AVIATION...ENTREKIN
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
142 PM EDT FRI APR 20 2012
.SYNOPSIS...
A WEAK AREA OF HIGH PRESSURE ACROSS THE AREA EARLY TODAY WILL LOSE
ITS INFLUENCE OVER THE WEATHER TONIGHT. A LOW PRESSURE SYSTEM WILL
MOVE ACROSS THE GREAT LAKES TONIGHT AND THEN INTO NEW ENGLAND
SATURDAY. AN ATTACHED COLD FRONT WILL CROSS THE AREA SATURDAY. LOW
PRESSURE WILL DEEPEN NEAR FLORIDA SUNDAY AND THEN STRENGTHEN WHILE
MOVING NORTHWARD ALONG THE FRONT THROUGH MONDAY. THE STRONG LOW WILL
THEN TRACK NORTH OF THE AREA MONDAY THROUGH TUESDAY. HIGH PRESSURE
WILL EVENTUALLY BUILD BACK ACROSS THE AREA BY THE MIDDLE OF NEXT
WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE STRATUS IS NOW GONE...AND THE FORECAST PROBLEM IS NOW BASED
ALMOST ENTIRELY ON THE CUMULUS/STRATOCUMULUS DECK COVERING MUCH
OF THE FORECAST AREA LATE THIS MORNING. THE LATEST RUC SUGGESTS
THAT THE AREA OF CLOUDINESS ACROSS SOUTHEAST PORTIONS CONSOLIDATES
EARLY THIS AFTERNOON...THEN MOVES NORTHEAST WITH THE BOUNDARY
LAYER FLOW.
THERE IS A BREAK DEVELOPING ACROSS THE SOUTHERN DELMARVA...BUT
THIS MAY NOT HAVE MUCH OF AN IMPACT ON THE SKY COVER ACROSS
EASTERN SECTIONS THIS AFTERNOON. BASED ON THE CLOUD COVER IN
PLACE...AND THE POTENTIAL FOR BREAKS THIS AFTERNOON...HIGH
TEMPERATURES WERE NUDGED DOWN ACROSS EASTERN SECTIONS. LESS
HEATING MAY MEAN LESS IN THE WAY OF SEA AND BAY BREEZES...AND
WINDS WERE ADJUSTED DOWN A BIT.
FURTHER WEST...THE CUMULUS IS MORE OR LESS BASED ON HEATING OF THE
MOISTENED BOUNDARY LAYER. THIS SHOULD MEAN MORE IN THE WAY OF
BREAK FOR SOUTHEAST PENNSYLVANIA THIS AFTERNOON...AND NOT AS MUCH
OF AN IMPACT FOR THE LEHIGH VALLEY AND THE HIGHER TERRAIN. IN
THESE AREAS...HIGH TEMPERATURES WERE NOT MODIFIED MUCH BASED ON
THE EXPECTED SUNSHINE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM SATURDAY/...
HERE WE WILL DEVIATE A BIT FROM THE WRF-NMMB AND TAKE AN AVERAGE OF
IT AND THE GFS. THE MOIST SERLY FLOW IS FORECAST TO PERSIST. AS SUCH
THE UPSLOPE, CONVERGENT FLOW SHOULD HELP DEVELOP CLOUDS. WE MIGHT BE
TOO FAST, BUT BELIEVE WE WILL GET THERE BEFORE THE NIGHT IS DONE.
BASED ON THE MODELS FORECASTING SOME LIGHT MEASURABLE, TOOK THIS AS
SOME UPSLOPING DRIZZLE OR LIGHT RAIN OCCURRING. WE KEPT A CHANCE IN
THE NORTHERN HALF OF OUR CWA. DO NOT THINK STAT GUIDANCE COULD GET
ANY CLOSER AND OTHER THAN PHL WHERE WE WENT ABOVE THEM BECAUSE OF
URBAN EFFECTS, PRETTY MUCH ACCEPTED IT.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
CLOUDS WILL BE INCREASING ACROSS THE AREA SATURDAY AS LOW PRESSURE
WILL BE TRACKING DOWN THE SAINT LAWRENCE VALLEY AND ITS ATTACHED
COLD FRONT WILL BE APPROACHING FROM THE WEST. SHOWERS AND SCATTERED
TSTMS WILL ACCOMPANY THE FRONT. THE NAM AND GFS ARE BOTH INDICATING
SOME SFC BASED CAPE IN THE 500 TO 1000 J/KG RANGE FOR SATURDAY...SO
WE WILL KEEP THE THUNDER IN THERE FOR NOW. SPC HAS A `SEE TEXT`
MENTION IN THE SWODY2 DISCUSSION FOR THE NORTHERN MIDDLE ATLANTIC
REGION. THE FRONT SLOWS AS IT MOVES EAST OF THE AREA SATURDAY NIGHT.
THIS WILL PROLONG THE PRECIP EVENT WITH LIGHTER AMOUNTS SAT NIGHT
AND HIGH CHC POPS.
THE MORE SIGNIFICANT EVENT IN THE EXTENDED WILL ARRIVE SUNDAY IN THE
FORM OF DEEP MOISTURE AND LIFT ASSOCIATED WITH THE STRENGTHENING LOW
MOVING NORTHWARD FROM FL. THE SHIELD OF RAIN WILL OVERSPREAD THE
AREA FROM THE SOUTH SUN MORNING AND PERSIST OVER THE AREA AT LEAST
UNTIL MON MORNING WITH THE POTENTIAL OF 1 TO 3 INCHES OF RAIN. THE
MODELS HAVE COME INTO BETTER AGREEMENT (COMPARED TO YESTERDAY) BUT
ARE STILL OFFERING DIFFERENT TRACK AFTER THEY ARRIVE AT OUR
LATITUDE. THE GFS TURNED THE DEEP SFC LOW MORE WESTWARD ACROSS PA
WHILE THE NAM AND 12Z EC TRACK THE SYSTEM NORTHWARD ACROSS THE
NEARSHORE WATERS. THE 12Z EC HOOKS THE LOW BACK WESTWARD ONCE IT
REACHES NYC HOWEVER. THE OVERNIGHT EXTENDED GRIDS HAVE BEEN MODIFIED
TO RESEMBLE THE NAM/12Z EC SOLUTIONS FOR THE MOST PART...NOT MUCH
DIFFERENT THE THE PREVIOUS FCST. HIGHER POPS AND NEW HPC QPF
GRAPHICS HAVE BEEN CREATED.
THE DEEP LOW WILL TRACK AWAY FROM THE AREA MON-WED. HIGH PRESSURE
WILL GRADUALLY BUILD BACK ACROSS THE AREA. WINDY AND COOL WEATHER
WILL BE ACROSS THE AREA MON-WED. POPS DECREASE BACK TO CHC LEVELS BY
MON AFTERNOON...THEN SLGT CHC FOR MON NIGHT AND TUE. TEMPERATURES
MAY BE LOW ENOUGH TO SUPPORT SOME SNOW ACROSS THE FAR NORTH...BUT IT
WILL BE VERY MARGINAL AND IT MAY BE A LOW ENOUGH PROBABILITY EVENT
TO NOT INCLUDE IN THE FCST ATTM.
WE ARE KEEPING A DRY FCST AT THE END OF THE EXTENDED PERIOD FOR NOW.
THE NEW EC HAS ARRIVED HOWEVER WITH ANOTHER SYNOPTIC SYSTEM ACROSS
THE AREA...WE`LL HAVE TO WATCH THIS FOR A FEW MORE MODEL RUNS TO SEE
IF HIGHER POPS WILL BE NEEDED.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE STRATUS HAS LIFTED INTO A CUMULUS/STRATOCUMULUS LAYER ACROSS
MUCH OF THE AREA EARLY THIS AFTERNOON. FROM KPHL NORTH AND
WEST...VFR CONDITIONS ARE EXPECTED FOR THE REMAINDER OF THE
AFTERNOON...WITH SOUTH WINDS NEAR 10 KNOTS. FOR KACY AND
KMIV...WHICH ARE CLOSER TO THE SOURCE OF THE MOISTURE FOR THE
CLOUDS...THE INVERSION IS LOWER...AND MVFR CONDITIONS ARE EXPECTED
INTO THE EARLY EVENING HOURS.
AFTER 0000 UTC...THE STRATUS AND FOG WILL RETURN FROM WEST TO
EAST...AS THE ONSHORE FLOW BRINGS MOISTURE BACK WEST. MVFR/IFR
CONDITIONS ARE EXPECTED AT KABE/KRDG...WHICH WILL BE FURTHEST FROM
THE MOISTURE SOURCE. MVFR CONDITIONS COULD RETURN TO THE KPHL METRO
AIRPORTS AS EARLY AFTER 0100 UTC SATURDAY...AS THE CLOUDINESS OVER
EASTERN NEW JERSEY GETS BACK WEST. IFR CONDITIONS ARE EXPECTED AFTER
0600 UTC FROM KPHL SOUTH AND EAST...WITH SOME LIFR CONDITIONS
POSSIBLE.
THE IFR/MVFR CONDITIONS SHOULD IMPROVE FROM WEST TO EAST BETWEEN 1300
UTC AND 1600 UTC SATURDAY. THE AIRMASS BECOMES MARGINALLY UNSTABLE
FROM WEST TO EAST...WITH THE BEST CHANCE OF SHOWERS AND
THUNDERSTORMS FROM THE I-95 CORRIDOR WEST. LOCAL MVFR CONDITIONS ARE
POSSIBLE WITH THE SHOWERS AND STORMS.
OUTLOOK...
SAT NIGHT...MVFR CONDITIONS DROPPING TO IFR. EVENING CONVECTION
SHOULD DIE OFF...BUT STEADIER RAIN IS POSSIBLE TOWARD 1200 UTC
SUNDAY.
SUN-MON...MOSTLY IFR CONDITIONS WITH LOW CIGS/VSBYS RAIN AND
GUSTY WINDS.
MON NGT-TUE...IMPROVEMENT TO VFR BY TUE ACROSS MOST AREAS BUT SCT SHOWERS
MAY CREATE LOWER CONDITIONS AT TIMES.
&&
.MARINE...
SUB SMALL CRAFT ADVISORY CONDITIONS ARE FORECAST TO CONTINUE TODAY
AND TONIGHT. WAVE WATCH GUIDANCE CONTINUES TO BE TOO HIGH WITH THE
EASTERLY SWELL AND WE ARE TAKING APPROXIMATELY A FOOT OFF THE
GUIDANCE. WINDS OVERALL TODAY SHOULD BE RELATIVELY LIGHT FROM THE
EAST AND SOUTHEAST. THERE WILL LIKELY BE AN INCREASE IN SPEED IN
DELAWARE BAY AGAIN LATER IN THE AFTERNOON AND EARLY IN THE EVENING
AS THE FLOW WILL BE UP THE BAY AGAIN.
WINDS SHOULD BACK MORE TO THE SOUTH TONIGHT, BUT OVERALL SPEEDS
SHOULD REMAIN LESS THAN 15KTS. SWELLS ARE NOT EXPECTED TO INCREASE
IN TIME TO CAUSE ANY SMALL CRAFT CONDITIONS.
OUTLOOK...
SMALL CRAFT CONDITIONS DEVELOPING SAT WITH GALES POSSIBLE SUN-MON.
A RETURN BACK TO SUB-SCA CONDITIONS BY TUE.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...O`HARA
NEAR TERM...HAYES
SHORT TERM...GIGI
LONG TERM...O`HARA
AVIATION...HAYES
MARINE...GIGI
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1253 PM CDT FRI APR 20 2012
.DISCUSSION...
ISSUED 949 AM CDT FRI APR 20 2012
MAIN CONCERN THIS MORNING IS WITH TEMPERATURES. THE COLD FRONT WAS
ROUGHLY ALONG OR JUST WEST OF THE I-57 CORRIDOR AS OF 9 AM.
TEMPERATURES AHEAD OF THE FRONT WERE APPROACHING 70 DEGREES IN THE
EXTREME SOUTHEAST CWA...WHERE CLOUDS HAVE ONLY RECENTLY BEGAN TO
THICKEN. BEHIND THE FRONT...TEMPERATURES HAVE DIPPED INTO THE 40S.
LATEST HRRR SHOWS THE FRONT REACHING LAWRENCEVILLE IN THE NOON TO
1 PM TIME FRAME. COLD AIR ADVECTION AND EXTENSIVE CLOUDINESS
BEHIND THE FRONT WILL RESULT IN LITTLE OR NO RISE IN TEMPERATURES
THIS AFTERNOON ACROSS THE NORTHWEST HALF OF THE CWA...WITH FALLING
TEMPERATURES IN THE SOUTHEAST HALF.
RAIN SHOWERS CONTINUE TO ADVANCE ACROSS THE CWA IN ROUGHLY A 50
MILE WIDE BAND...SO PRECIPITATION HAS LARGELY ENDED WEST OF A
BLOOMINGTON TO TAYLORVILLE LINE. MOST OF THE PRECIPITATION SHOULD
BE OUT OF THE CWA BY MID AFTERNOON...EXCEPT IN THE FAR SOUTHEAST.
ZONE/GRID UPDATES WILL BE OUT AROUND 10 AM TO UPDATE THE
TEMPERATURE AND RAINFALL TRENDS.
GEELHART
&&
.AVIATION...
ISSUED 1253 PM CDT FRI APR 20 2012
COLD FRONT HAS PASSED ALL THE TAF SITES...SO MAIN CONCERN IS WITH
MVFR AND BORDERLINE IFR CEILINGS THE NEXT SEVERAL HOURS. LOWEST
CEILINGS AROUND 700-800 FEET LINGERING AT KDEC/KCMI WHERE THERE
WILL ALSO BE SOME LOWER VISIBILITIES IN RAIN SHOWERS THROUGH ABOUT
21Z. SATELLITE IMAGERY SHOWING CLOUDS BELOW 3000 FEET AS FAR
NORTHWEST AS CENTRAL IOWA. CEILINGS WILL GRADUALLY RISE THROUGH
THE MVFR RANGE THIS AFTERNOON...WITH CLOUDS SCATTERING OUT EARLY
THIS EVENING. HOWEVER...IT MAY TAKE UNTIL AROUND 07-09Z OR SO FOR
THIS TO OCCUR FURTHER EAST TOWARD KCMI.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 309 AM CDT FRI APR 20 2012
SHORT TERM...TODAY THROUGH SUNDAY
COLD FRONT WILL PUSH EASTWARD ACROSS THE AREA TODAY...ACCOMPANIED
BY A BAND OF LIGHT SHOWERS. 00Z UPPER AIR ANALYSIS SHOWS LIMITED
MOISTURE FOR THE FRONT TO WORK WITH...WITH ONLY A NARROW RIBBON OF
5-10C 850MB DEWPOINTS EXTENDING FROM TEXAS NORTHEASTWARD INTO
IOWA. IN ADDITION...00Z KILX AND KDVN UPPER AIR SOUNDINGS FEATURED
A VERY DRY LOW-LEVEL AIRMASS BELOW 600MB. HRRR AND 4KM WRF-NMM
BOTH SUGGEST THE BAND OF SHOWERS WILL GRADUALLY DISSIPATE AS IT
WORKS ITS WAY INTO THE DRIER ENVIRONMENT ACROSS CENTRAL ILLINOIS
THIS MORNING. LATEST RADAR MOSAIC CONTINUES TO INDICATE A WEAKENING
TREND...WHILE IR SATELLITE SHOWS WARMING CLOUD TOPS. END RESULT
WILL BE A BRIEF PERIOD OF SCATTERED SHOWERS ALONG AND IMMEDIATELY
BEHIND THE FRONT. RAINFALL TOTALS WILL REMAIN LIGHT...GENERALLY
UNDER ONE TENTH OF AN INCH. ONCE THE FRONT PASSES...BREEZY AND
COOLER CONDITIONS WILL SPILL INTO THE REGION LATER THIS MORNING
INTO THE AFTERNOON. WITH OVERCAST CONDITIONS AND NORTHWESTERLY
WINDS GUSTING TO 25 MPH AT TIMES...TEMPS WILL HOVER IN THE LOWER
TO MIDDLE 50S BEHIND THE FRONT.
EXTENSIVE CLOUD COVER BEHIND THE BOUNDARY WILL ENSURE MOSTLY
CLOUDY CONDITIONS THROUGH EARLY EVENING...WITH CLEARING SKIES
DEVELOPING ACROSS THE ILLINOIS RIVER VALLEY TOWARD MIDNIGHT...THEN
FURTHER EAST ACROSS THE REMAINDER OF THE AREA OVERNIGHT. PATCHY
FROST WILL BE POSSIBLE ALONG AND NORTHWEST OF A RUSHVILLE TO
BLOOMINGTON-NORMAL LINE...WHERE SKIES WILL CLEAR EARLIEST AND
WINDS WILL DIMINISH TO LESS THAN 5 MPH. OVERNIGHT LOWS WILL RANGE
FROM THE MIDDLE 30S NORTHWEST...TO THE LOWER 40S FAR SOUTHEAST.
COOL/DRY WEATHER WILL BE ON TAP FOR SATURDAY...WITH HIGHS ONLY
REACHING THE MIDDLE TO UPPER 50S. LOW TEMPS SATURDAY NIGHT WILL
LIKELY BE A COUPLE OF DEGREES WARMER THAN TONIGHT DUE TO CLOUD
COVER FROM AN APPROACHING UPPER-LEVEL DISTURBANCE...SO CHANCES FOR
FROST WILL BE REDUCED. IN FACT...MODELS ARE TRYING TO SQUEEZE OUT
SOME LIGHT QPF WITH THE APPROACHING WAVE...HOWEVER THINK AIRMASS
WILL BE TOO DRY TO SUPPORT MEASURABLE PRECIP...SO HAVE MAINTAINED A
DRY FORECAST.
LONG TERM...MONDAY THROUGH THURSDAY
DEEP UPPER LOW IS EXPECTED TO DEVELOP OVER THE EASTERN CONUS EARLY
NEXT WEEK...WITH MODELS STILL VARYING ON ITS EVENTUAL DEPARTURE.
GIVEN HIGHLY AMPLIFIED NATURE OF THE FLOW...THINK SLOWER IS THE
WAY TO GO. END RESULT WILL BE COOL/DRY WEATHER THROUGH AT LEAST
TUESDAY...WITH A MARKED WARMING TREND BEGINNING BY THE MIDDLE OF
THE WEEK AS UPPER HEIGHTS BEGIN TO RISE. HIGH TEMPS WILL START OUT
IN THE LOWER 60S ON MONDAY...THEN WILL CLIMB WELL INTO THE 70S BY
WEDNESDAY AND THURSDAY. RAIN CHANCES THROUGH THE PERIOD APPEAR TO
BE RATHER MINIMAL...WITH THE BEST SHOT AT PRECIP OCCURRING ON
WEDNESDAY AS WARMER AIRMASS BEGINS TO MAKE ITS RETURN.
BARNES
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1225 PM CDT FRI APR 20 2012
.AVIATION...
MVFR CONDITIONS DUE TO CIGS AROUND 2KFT WILL GRADUALLY IMPROVE
TO VFR LATE THIS AFTERNOON AND EARLY THIS EVENING AS CLOUDS CLEAR
FROM WEST TO EAST. GUSTY NORTH WINDS WILL ALSO DIMINISH BY THIS
EVENING. WINDS WILL BECOME LIGHT SOUTH TO SOUTHEAST BY SATURDAY
MORNING.
A SURFACE RIDGE OVER THE NORTHERN PLAINS WILL MOVE SOUTHEAST AND
SHOULD BE CENTERED JUST WEST OF THE MISSISSIPPI RIVER BY SATURDAY
MORNING. CLEARING SKIES AND LIGHT WINDS ACCOMPANYING THE RIDGE WILL
CREATE FAVORABLE CONDITIONS FOR FROST LATE TONIGHT.
DLF
&&
.PREV DISCUSSION... /ISSUED 640 AM CDT FRI APR 20 2012/
UPDATE...
BASED ON RADAR AND RUC TRENDS THE THREAT OF MEASURABLE
PRECIPITATION FOR THE CWFA IS NOW OVER. RUC CONTINUES TO SHOW F
VECTOR CONVERGENCE AND REASONABLY LOW CONDENSATION PRESSURE
DEFICITS THIS MORNING WHICH MAY ALLOW PATCHY DRIZZLE OR SPRINKLES
TO BE SEEN. ANY PRECIP WILL END FROM WEST TO EAST DURING THE
MORNING HOURS.
DPROG/DT OF THE MODELS INDICATE HIGH LEVEL MOISTURE INCREASING
TONIGHT WHICH STRONGLY SUGGESTS THE CI/CS ASSOCIATED WITH THE
SHORTWAVE TOPPING THE RIDGE IN THE PAC NW WILL ARRIVE AFTER
MIDNIGHT. IF THIS TREND IS CORRECT...THE HIGH LEVEL CLOUD COVER
WOULD HAVE AN IMPACT ON TEMPERATURES TONIGHT WHICH WOULD THEN PLAY
SIGNIFICANTLY INTO ANY FROST AND FREEZE POTENTIAL.
AN UPDATE REFLECTING THE IMMEDIATE SHORT TERM TRENDS WILL BE
AVAILABLE SHORTLY. ..08..
AVIATION...
LIFR TO LOW MVFR CONDITIONS WILL SLOWLY IMPROVE TO VFR CONDITIONS
THROUGH 00Z/21 WITH GUSTY WINDS. PATCHY DRIZZLE OR SPRINKLES MAY BE
POSSIBLE THROUGH 18Z/20. AFT 00Z/21 WINDS WILL DIMINISH AS HIGH
PRESSURE QUICKLY MOVES THROUGH THE AREA. ..08..
PREV DISCUSSION... /ISSUED 345 AM CDT FRI APR 20 2012/
SYNOPSIS...
06Z SFC ANALYSIS HAS THE LOW JUST SOUTHEAST OF THE QUAD CITIES WITH
A WARM FRONT EAST TO THE SOUTH SUBURBS OF CHICAGO. THE COLD FRONT
RAN INTO SOUTHWEST MISSOURI. DEW POINTS AROUND THE FRONTS WERE IN
THE 50S WITH MAINLY 40S OVER MOST OF THE PLAINS AND MIDWEST. DEW
POINTS IN THE 30S WERE IN THE UPPER MIDWEST AND WESTERN GREAT LAKES.
RADAR TRENDS THE PAST SEVERAL HOURS SHOW A BACK EDGE OF THE MORE
SUBSTANTIAL PRECIPITATION FROM ROUGHLY KRFD TO KUIN. SFC OBS
REPORTED DZ OR VERY LIGHT RAIN BACK INTO EASTERN AND CENTRAL IOWA.
SHORT TERM...TODAY AND TONIGHT
RUC TRENDS WITH CONDENSATION PRESSURE DEFICITS HAVE BEEN USEFUL IN
DEPICTING PRECIPITATION TRENDS AND WERE USED FOR THE IMMEDIATE SHORT
TERM.
BASED ON RADAR AND RUC TRENDS...ANY MEASURABLE PRECIPITATION SHOULD
BE ACROSS THE FAR EAST AND SOUTHEAST PARTS OF THE CWFA AT 12Z. THE
REMAINDER OF THE AREA SHOULD SEE DRIZZLE/SPRINKLES DUE TO LOW
CONDENSATION PRESSURE DEFICITS COMBINED WITH FORCING AND F VECTOR
CONVERGENCE THROUGH MID MORNING. AS CONDENSATION PRESSURE DEFICITS
RISE THE PRECIPITATION WILL END FROM WEST TO EAST FROM LATE MORNING
THROUGH MID DAY.
CLOUD COVER AND INITIAL PRECIPITATION THIS MORNING WILL HOLD
TEMPERATURES DOWN BUT CLEARING DURING THE MID TO LATE AFTERNOON FROM
WEST TO EAST SHOULD ALLOW TEMPERATURES TO CLIMB INTO THE LOW TO MID
50S.
TONIGHT...QUIET AND CHILLY CONDITIONS WILL BE SEEN ACROSS THE AREA.
HIGH PRESSURE OVER THE AREA WILL ALLOW WINDS TO BECOME LIGHT WITH
FROST POSSIBLE. THE POSSIBILITY DOES EXIST THAT A FREEZE MAY OCCUR
ACROSS ABOUT THE NORTHERN QUARTER TO THIRD OF THE CWFA. HOWEVER...
THE MODELS ARE SHOWING INCREASES IN MOISTURE ALOFT AFTER MIDNIGHT
SUGGESTING CI/CS MOVING INTO THE AREA. IF THIS OCCURS TEMPERATURES
WOULD BE HELD UP...POSSIBLY ABOVE FREEZING.
GIVEN THIS UNCERTAINTY...ANY DECISION REGARDING FROST/FREEZE
HEADLINES WILL BE DEFERRED TO THE NEXT SHIFT. ..08..
LONG TERM...SATURDAY THROUGH NEXT THURSDAY...
OUR NEXT PRECIPITATION CHANCES COME ON SATURDAY AND SATURDAY
NIGHT AS A WEAK SHORTWAVE WITH A WING OF WARM AIR ADVECTION AND
ISENTROPIC LIFT AHEAD OF THE SHORTWAVE. THERE IS JUST ENOUGH
MOISTURE FOR THIS TO SQUEEZE OUT SOME SHOWERS...THOUGH MODELS ARE
SHOWING SOME DIFFERENCES WITH THIS RELATIVELY WEAK FEATURE. NAM
IS THE ODD MODEL OUT THIS MORNING...AS IT IS FARTHER EAST AND
SLIGHTLY WEAKER THAN THE OTHER MODELS HAVE. HAVE IN GENERAL TRIED
TO FOLLOW A BLEND OF THE GFS/ECMWF/UKMET SOLUTIONS ON THIS
FEATURE. WHILE THE MID LEVEL CONVERGENCE SEEMS TO LINGER ON SUNDAY
AND SUNDAY NIGHT...IT DOES NOT APPEAR THAT THERE IS ENOUGH
MOISTURE TO GET ANY SHOWERS GOING AGAIN ON SUNDAY. FOR NOW THE
TIME RANGE WITH THE HIGHEST POTENTIAL FOR PRECIPITATION IS
SATURDAY NIGHT. TEMPERATURES TO BE A LITTLE COOLER ON SATURDAY
WITH THE BAND OF PRECIPITATION MOVING INTO THE AREA...BUT
GRADUALLY WARM FOR SUNDAY AS THE MID LEVEL WARM AIR ADVECTION SETS
BACK IN QUICKLY BEHIND THE SHORTWAVE.
WE REMAIN IN STRONG NORTHWEST FLOW ON MONDAY THROUGH AT LEAST
WEDNESDAY...WITH STRONGLY AMPLIFIED FLOW OVER THE CONUS...WITH THE
DEEP TROUGH OVER THE EAST AND STRONG RIDGE OUT WEST. IT IS
DIFFICULT TO GET A GULF FEED FROM A SOUTHWEST LOW LEVEL FEED OUT OF
THIS TYPE OF SYSTEM...SO MOST SYSTEMS ARE GOING TO HAVE TO DRAG IN
THEIR OWN MOISTURE FROM THE PACIFIC...AND THEN MAKE THEIR WAY OVER
THE RIDGE. TUESDAY AND WEDNESDAY HAVE ANOTHER CHANCE FOR
PRECIPITATION AS WE GET A SLIGHTLY STRONGER SHORTWAVE THROUGH HERE.
SOME MODELS ARE EVEN BRINGING A SURFACE LOW ACROSS THE REGION.
OTHERS SIMPLY SETTLE A TROUGH AXIS ACROSS THE AREA. TOUGH CALL FOR
NOW...AND HAVE MAINTAINED SLIGHT CHANCE OR EVEN LOW CHANCE POP FOR
THE SOUTHERN PORTIONS OF THE FORECAST AREA. AS MOISTURE IS A
LIMITING FACTOR FOR THIS STORM...DO NOT ANTICIPATE HAVING ENOUGH
MOISTURE TO ACT UPON...NOR CAN WE EXPECT A REINFORCING SYSTEM TO
MOVE THROUGH LATER ON IN THE EVENING. ..LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
210 PM EDT FRI APR 20 2012
.UPDATE...
ISSUED AT 1047 AM EDT FRI APR 20 2012
FCST IN FINE SHAPE. EXPECT TREND TOWARD IMPROVING WEATHER THROUGH
REST OF THE DAY. RADAR AND SFC OBS/WEB CAMS INDICATE BACK EDGE OF
PRECIPITATION FM NEAR ERY THROUGH ISQ AND ACROSS NORTHERN LK MICHIGAN
INTO DOOR COUNTY WISCONSIN. WV/RUC ANALYSIS SHOWS STRONGEST SHORTWAVE
OVR EASTERN CWA BUT ANOTHER WEAKER WAVE IS LIFTING OUT OF WI AS WELL.
BASED ON SHARPENING OF RADAR ECHOES LAST HR APPEARS THIS WAVE MAY BE
ENHANCING MID-LEVEL DEFORMATION OVR THE EASTERN CWA. RUC PICKS UP ON
THIS H7-H5 DEFORMATION AND SHOWS IT COLLAPSING 18Z-21Z AS SHORTWAVE
TROUGH MOVES EAST.
WEB CAMS SHOW MAINLY WET CONDITIONS OVR THE EAST THOUGH SOME SNOW
MAY BE MIXING IN AT TIMES WITH SFC TEMPS IN THE MIDDLE 30S. ANY SNOW
ACCUMS WILL BE MINIMAL REST OF THE MORNING. BY EARLY AFTN...PRECIP
IS EXPECTED TO BE MAINLY GONE AND SKIES SHOULD CLEAR OUT IN THE
CNTRL AND EAST. NORTHEAST WINDS PROVIDING UPSLOPE HELP AND IS HOLDING
IN POCKET OF LOWER CLOUDS OVR CNTRL CWA /SAW REPORTING OVC005 AT 14Z/
BUT ALL CLOUDS SHOULD FADE AWAY THROUGH AFTN AS LARGER SCALE FORCING
DEPARTS THE AREA. UPDATED/PUBLISHED GRIDS AND TEXT PRODUCTS ARE OUT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 543 AM EDT FRI APR 20 2012
WATER VAPOR LOOP SHOWS SHORTWAVE MOVING THROUGH WI WITH COUPLED UPR
JET STRUCTURE AND ASSOC FRONTOGENETIC FORCING SUPPORTING BAND OF
PCPN FROM NE WI INTO SCNTRL UPR MI AND NRN LOWER MI. REPORTS THUS
FAR FROM THIS PCPN BAND OVER NCNTRL/NE WI INTO MENOMINEE COUNTY
INDICATE A MIX OF RAIN AND SNOW. MOST SNOW ACCUMULATION APPEARS TO
BE LIGHT...LESS THAN AN INCH...ALTHOUGH THERE WAS A PUBLIC REPORT OF
2 INCHES IN DAGGETT...MAINLY IN GRASSY AREAS.
TODAY...GIVEN THE LACK OF ANY SIGNIFICANT SNOW ACCUMULATION REPORTS
AND THE FACT THAT PCPN UPSTREAM OVER WI APPEARS TO BE TAPERING OFF
AS NOTED ON RADAR LOOP...HAVE DECIDED TO DROP THE WINTER WX ADVISORY
FOR MENOMINEE COUNTY. MODELS SHOW UPR JET SUPPORT AND ASSOC FGEN
FORCING FALLING APART THROUGH THE MORNING HRS AS THE SYSTEM MOVES
EAST. ANY ADDITIONAL SNOW ACCUMULATION FROM THE SYSTEM OVER SCNTRL
AND ERN PORTIONS OF THE CWA WILL BE LESS THAN AN INCH BEFORE THE
PCPN ENDS LATER THIS MORNING.
THE REST OF THE CWA WILL BE QUIET AS SFC RDG BUILDS IN FROM THE WEST
IN THE WAKE OF THE LOW PRESSURE SYSTEM. MODEL SNDGS INDICATE Q-VECT
DIV SPREADING IN FROM THE WEST WITH ASSOC SHARP SUBSIDENCE/DRYING
WHICH SHOULD LEAD TO SUNSHINE FOR THE MAJORITY OF THE CWA BY LATE
MORNING/EARLY AFTN. DESPITE INCREASING SUNSHINE...LOOK FOR
TEMPERATURES TO ONLY RISE INTO THE LOWER TO MID 40S AS WE WILL BE
COLD ADVECTING IN A 10-20 KT N-NE FLOW.
TONIGHT INTO SATURDAY...HIGH PRESSURE BUILDING INTO NORTHERN ONTARIO
AND THE WESTERN GREAT LAKES WILL RESULT IN DRY BUT CONTINUED COOL
WEATHER. EXPECT IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT OVER
WRN INTERIOR LOCATIONS AS THE SFC RDG AXIS MOVES OVER THE AREA AND
PCPN WATER VALUES FALL BLO .25 INCH. EXPECT LOWS RANGING FROM THE
LOWER 20S WRN INTERIOR TO THE UPR 20S/LOWER 30S EAST AND NEAR THE
GREAT LAKES. 850MB TEMPERATURES FALLING TO AROUND -6C ON SATURDAY IN
A WEAK N-NE FLOW WILL RESULT IN HIGH TEMPS ONLY IN THE 40S FOR MOST
AREAS...EXCEPT POSSIBLY APPROACHING 50F IN A FEW LOCATONS ALONG THE
WI BDR.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 543 AM EDT FRI APR 20 2012
HIGH PRESSURE WILL BE THE RULE AT THE SFC /AT LEAST MOST OF THIS
LONG RANGE/. HOWEVER...THE 500MB PATTERN WILL NOT ALLOW US A
COMPLETELY QUIET END TO OUR WEEKEND AND WEEK AHEAD WITH DOMINANT NW
FLOW ALOFT. THE 500MB OPEN WAVE/TROUGH WILL NOT MOVE FAR BY 00Z
SUNDAY...FROM W LAKE SUPERIOR THROUGH TX EARLY THIS MORNING...TO
LAKE HURON AND THE EASTERN GULF OF MEXICO. WHILE A COUPLE OF SMALLER
DISTURBANCES WILL SLIDE IN FROM THE WEST...KEEPING THE TROUGH
NEARBY...THE MAIN FEATURE OF INTEREST WILL BE WELL TO OUR SOUTH.
WILL DISMISS THE NAM SOLUTION FOR MUCH OF THIS FORECAST PERIOD....AS
IT LOOKS TO BE ON ITS OWN...PARTICULARLY AS WE MOVE INTO SATURDAY
NIGHT AND SUNDAY. THIS IS MAINLY DUE TO THE HANDLING OF THE A 500MB
WAVE EJECTING OUR WAY FROM THE LOW CURRENTLY SET UP OVER THE GULF OF
AK. THE NAM ATTEMPTS TO WRAP IT UP OVER THE CWA SUNDAY AFTERNOON
INSTEAD OF OVER THE CENTRAL APPALACHIANS/TN VALLEY AROUND THE SAME
TIME...LIKE THE CANADIAN/GFS/ECMWF. WIND WISE ON SUNDAY THE NAM IS
ROUGHLY 10KTS STRONGER THAN THE GFS FROM THE SFC UP THROUGH AT LEAST
500MB. THE 20/06Z RUN OF THE NAM EVEN ATTEMPTS TO SPIT OUT 0.25IN
RAIN WITH THIS FEATURE...WITH LITTLE MORE THAN A FEW ADDITIONAL
CLOUDS OFF THE REMAINING MODELS. WHILE THE LATEST 20/00Z LOOKS TO
PLAY UP THE MIDDLE GROUND BETWEEN THE QUICKER GFS AND NAM.
RH VALUES MAY BE TOO HIGH FOR SUNDAY...GIVEN THE MIXED DEWPOINT
VALUES IN THE TEENS EAST. LAKE BREEZES WILL BE THE MAIN CONCERN FIRE
WISE...IN THE LOW RH AREAS. STILL...WITH SLIGHTLY BELOW NORMAL
TEMPERATURES AND OVERALL LIGHT WINDS OVERALL WILL NOT HIGHLIGHT FIRE
WEATHER TOO MUCH.
WILL NOT GET INTO TOO MANY DETAILS OF THE LATTER PART OF THIS
FORECAST...WITH THE RETROGRADING STACKED SFC/500MB LOW SLIDING UP
THE EASTERN SEABOARD SUNDAY AND MONDAY...BEFORE SHIFTING ACROSS THE
LOWER GREAT LAKES AND WESTERN QUEBEC MONDAY AFTERNOON THROUGH MONDAY
NIGHT. AT THIS POINT...MUCH OF THE PRECIP AND EVEN CLOUD COVER LOOK
TO STAY TO OUR EAST. WE CAN STILL EXPECT SOME INCREASED COOL N/NNW
WINDS OFF LAKE SUPERIOR MONDAY AFTERNOON THROUGH AT LEAST TUESDAY
OVER THE EAST HALF OF THE CWA. EVEN WITH THIS FEATURE NEARING...LOOK
FOR A SLOW BUT STEADY WARMUP FROM MONDAY THROUGH THURSDAY...WITH
HIGH TEMPS IN THE MID 50S TO NEAR 60F BY THURSDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 207 PM EDT FRI APR 20 2012
NORTH TO NORTHEAST WINDS REMAIN GUSTY AT THE TERMINALS THIS AFTN BUT
WILL DIMINISH THIS EVENING AS HIGH PRESSURE BUILDS IN FROM ONTARIO.
LINGERING SUB 2KFT STRATOCU AT SAW BUT VISIBLE SATELLITE SHOWS SIGNS
THIS SHOULD DISSIPATE BY LATE AFTN. LARGE SWATH OF LOW CLOUDS
UPSTREAM NORTH OF LK SUPERIOR MAY COME INTO THE AREA TONIGHT. PUT A
LOWER MVFR CIG IN AT SAW WITH UPSLOPE NORTHEAST WINDS AND ADDED
MOISTURE OFF LK SUPERIOR. ONLY SCT MVFR SHOULD OCCUR AT CMX OR IWD.
POTENTIAL THAT CIGS MAY GO LOWER AT SAW AS WHILE UPSLOPE MOISTENING
OCCURS...THERE COULD BE RADIATIONAL COOLING AS WELL /FAVORING
BUILDING DOWN OF CIGS/. LOW RISK ATTM...SO JUST WENT WITH CIGS OF
1KFT. LOWER CIGS SHOULD SCT OUT BY MID MORNING SATURDAY. SCT-BKN
MID CLOUDS WILL PUSH INTO CMX AND IWD THROUGH THE MORNING THOUGH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 543 AM EDT FRI APR 20 2012
WINDS LESS THAN 30KTS WILL DOMINATE THE FORECAST PERIOD. AN EXITING
LOW TEMPORARILY ACROSS S LOWER LAKE MICHIGAN WILL PUSH ACROSS THE
LOWER GREAT LAKES THIS EVENING...MAKING WAY FOR A RIDGE TO BUILD
ACROSS THE UPPER GREAT LAKES FROM CANADA. EXPECT A STRONG LOW TO
PUSH NORTHWARD ACROSS THE EASTERN SEABOARD...MAKING ITS WAY NEAR
LAKE ONTARIO MONDAY AFTERNOON. THE RIDGE OVERHEAD WILL SLOWLY WEAKEN
AS A RESULT...AND SLOWLY BE REPLACED BY A TROUGH INVADING FROM THE
EAST MONDAY NIGHT INTO TUESDAY.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLA
SHORT TERM...VOSS
LONG TERM...KF
AVIATION...JLA
MARINE...KF
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
139 PM EDT FRI APR 20 2012
.SYNOPSIS...
ISSUED AT 400 AM EDT FRI APR 20 2012
LOW PRESSURE WILL MOVE ACROSS SOUTHERN LOWER MICHIGAN TODAY BRINGING
RAIN SHOWERS. A DRY AND COOLER WEEKEND IS EXPECTED WITH HIGHS IN THE
50S. TEMPERATURES WILL UNDERGO A SLIGHT MODERATING TREND TOWARD THE
MIDDLE PORTION OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1210 PM EDT FRI APR 20 2012
HAVE UPDATED FORECASTS TO REFINE TIMING OF PRECIPITATION EXITING
THE AREA THIS AFTERNOON AND EVENING. ALSO LOWERED HIGH
TEMPERATURES.
RADAR CURRENTLY SHOWS A SHARP BACK EDGE TO THE AREA OF
PRECIPITATION CREEPING SOUTHEAST THROUGH THE AREA. HRRR MODEL
GUIDANCE SUGGESTS THAT SOME SMALL AREAS OF RAIN COULD RE-DEVELOP
BEHIND THIS EDGE...WHICH MAKES SENSE GIVEN A WEAK POT VORT MAX
LIFTING NE TOWARDS THE CWFA AT THIS TIME. CLOUDS STILL ARE
EXPECTED TO ERODE FROM NW TO SE EARLY TONIGHT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON)
ISSUED AT 400 AM EDT FRI APR 20 2012
LOW PRESSURE WILL TRACK ENE FROM NEAR BEH AT 12Z THIS MORNING TO
NEAR TORONTO BY THIS EVENING BRINGING SHOWERS TO OUR FCST AREA
TODAY. CANNOT COMPLETELY RULE OUT AN ISOLATED RUMBLE OF THUNDER
LATER TODAY BUT GIVEN LACK OF INSTABILITY THE THREAT OF STORMS TODAY
IS QUITE LOW. SHOWERS WILL GRADUALLY TAPER OFF BY MID TO LATE AFTN
AND SOME WET SNOW FLAKES MAY TRY TO MIX IN ACROSS CENTRAL LOWER MI
THIS AFTERNOON AND EVENING BEFORE PRECIPITATION ENDS.
NORTHERLY FLOW CAA TONIGHT WITH GRADUAL CLEARING MAY POTENTIALLY SET
THE STAGE FOR SOME PATCHY FROST ACROSS PORTIONS OF OUR FCST AREA
DURING THE EARLY MORNING HOURS SATURDAY. LOW TEMPS MAY DIP INTO
THE UPPER 20S ACROSS OUR NORTHERN FCST AREA DURING THE EARLY MORNING
HOURS SATURDAY ON PURE CAA/CLEARING SKIES LATE. HOWEVER THE
WINDS/DECENT BOUNDARY LAYER MIXING SHOULD MITIGATE FROST POTENTIAL.
PARTLY SUNNY AND COOL CONDITIONS ON TAP FOR SATURDAY WITH MAX TEMPS
REACHING THE LOW TO MID 50S AFTER A COOL START TO THE DAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM EDT FRI APR 20 2012
UPPER TROUGH AXIS DEEPENS ACROSS THE GREAT LAKES OVER THE WEEKEND
BUT FAIR WEATHER EXPECTED UNDER SFC RIDGING. TEMPS FALL BELOW
FREEZING ONCE AGAIN SATURDAY AND SUNDAY MORNINGS ACROSS MUCH LOWER
MICHIGAN.
THE DEEPENING TROUGH AXIS RESULTS IN AN EAST COAST CYCLONE AND
EVENTUAL CUT OFF LOW THAT RETROGRADES TOWARDS THE EASTERN GREAT
LAKES BY EARLY NEXT WEEK. FOR MUCH OF NEXT WEEK THE CENTRAL GREAT
LAKES WILL BE IN BETWEEN THIS LOW AND A BIG UPPER LOW MOVING INTO
THE WESTERN CONUS. KEPT LOW CHANCE POPS IN THE FORECAST FOR TUESDAY
FOR NOW BUT CONFIDENCE IS LOW...AS THE 00Z GFS AND EURO SHOW THE
WESTERN EDGE OF THE PRECIP SHIELD BARELY REACHING THE EASTERN
FORECAST AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 140 PM EDT FRI APR 20 2012
FEW CHANGES TO PREVIOUS THINKING. IFR CIGS AND VSBYS ARE EXPECTED
BENEATH AND IMMEDIATELY BEHIND A NARROW BAND OF RAIN MOVING
SOUTHEAST THROUGH THE AREA. CIGS BEHIND THE BAND HAVE TRENDED
UPWARD OVERALL...BUT STILL EXPECT FUEL ALTERNATE CIGS BELOW 20KFT
TO PERSIST AT LEAST A FEW HOURS AFTER THE RAIN PASSES EACH
TERMINAL. STILL LOOKS LIKE RAPID CLEARING CAN BE EXPECTED ACROSS
THE AREA...MAINLY AFT 00Z.
&&
.MARINE...
ISSUED AT 1210 PM EDT FRI APR 20 2012
KEEPING GALE WARNING IN THE FORECAST. AREAS SOUTH OF MUSKEGON MAY
SEE SUSTAINED WINDS OF 20 TO 30 KNOTS...BUT FREQUENT GUSTS ABOVE
35 KNOTS WILL REMAIN POSSIBLE.
&&
.HYDROLOGY...
ISSUED AT 400 AM EDT FRI APR 20 2012
MORE SHOWERS ON THE WAY FOR LATER THIS MORNING INTO THE AFTERNOON
WITH QPF AMOUNTS UNDER A HALF AN INCH. THIS WILL NOT BE ENOUGH TO
RESULT IN ANY SIGNIFICANT HYDRO ISSUES WITH DRY WX ALSO ANTICIPATED
TONIGHT THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...TJT
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...TJT
HYDROLOGY...LAURENS
MARINE...TJT
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1211 PM EDT FRI APR 20 2012
.SYNOPSIS...
ISSUED AT 400 AM EDT FRI APR 20 2012
LOW PRESSURE WILL MOVE ACROSS SOUTHERN LOWER MICHIGAN TODAY BRINGING
RAIN SHOWERS. A DRY AND COOLER WEEKEND IS EXPECTED WITH HIGHS IN THE
50S. TEMPERATURES WILL UNDERGO A SLIGHT MODERATING TREND TOWARD THE
MIDDLE PORTION OF NEXT WEEK.
&&
.UPDATE...
ISSUED AT 1210 PM EDT FRI APR 20 2012
HAVE UPDATED FORECASTS TO REFINE TIMING OF PRECIPITATION EXITING
THE AREA THIS AFTERNOON AND EVENING. ALSO LOWERED HIGH
TEMPERATURES.
RADAR CURRENTLY SHOWS A SHARP BACK EDGE TO THE AREA OF
PRECIPITATION CREEPING SOUTHEAST THROUGH THE AREA. HRRR MODEL
GUIDANCE SUGGESTS THAT SOME SMALL AREAS OF RAIN COULD RE-DEVELOP
BEHIND THIS EDGE...WHICH MAKES SENSE GIVEN A WEAK POT VORT MAX
LIFTING NE TOWARDS THE CWFA AT THIS TIME. CLOUDS STILL ARE
EXPECTED TO ERODE FROM NW TO SE EARLY TONIGHT.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY AFTERNOON)
ISSUED AT 400 AM EDT FRI APR 20 2012
LOW PRESSURE WILL TRACK ENE FROM NEAR BEH AT 12Z THIS MORNING TO
NEAR TORONTO BY THIS EVENING BRINGING SHOWERS TO OUR FCST AREA
TODAY. CANNOT COMPLETELY RULE OUT AN ISOLATED RUMBLE OF THUNDER
LATER TODAY BUT GIVEN LACK OF INSTABILITY THE THREAT OF STORMS TODAY
IS QUITE LOW. SHOWERS WILL GRADUALLY TAPER OFF BY MID TO LATE AFTN
AND SOME WET SNOW FLAKES MAY TRY TO MIX IN ACROSS CENTRAL LOWER MI
THIS AFTERNOON AND EVENING BEFORE PRECIPITATION ENDS.
NORTHERLY FLOW CAA TONIGHT WITH GRADUAL CLEARING MAY POTENTIALLY SET
THE STAGE FOR SOME PATCHY FROST ACROSS PORTIONS OF OUR FCST AREA
DURING THE EARLY MORNING HOURS SATURDAY. LOW TEMPS MAY DIP INTO
THE UPPER 20S ACROSS OUR NORTHERN FCST AREA DURING THE EARLY MORNING
HOURS SATURDAY ON PURE CAA/CLEARING SKIES LATE. HOWEVER THE
WINDS/DECENT BOUNDARY LAYER MIXING SHOULD MITIGATE FROST POTENTIAL.
PARTLY SUNNY AND COOL CONDITIONS ON TAP FOR SATURDAY WITH MAX TEMPS
REACHING THE LOW TO MID 50S AFTER A COOL START TO THE DAY.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 400 AM EDT FRI APR 20 2012
UPPER TROUGH AXIS DEEPENS ACROSS THE GREAT LAKES OVER THE WEEKEND
BUT FAIR WEATHER EXPECTED UNDER SFC RIDGING. TEMPS FALL BELOW
FREEZING ONCE AGAIN SATURDAY AND SUNDAY MORNINGS ACROSS MUCH LOWER
MICHIGAN.
THE DEEPENING TROUGH AXIS RESULTS IN AN EAST COAST CYCLONE AND
EVENTUAL CUT OFF LOW THAT RETROGRADES TOWARDS THE EASTERN GREAT
LAKES BY EARLY NEXT WEEK. FOR MUCH OF NEXT WEEK THE CENTRAL GREAT
LAKES WILL BE IN BETWEEN THIS LOW AND A BIG UPPER LOW MOVING INTO
THE WESTERN CONUS. KEPT LOW CHANCE POPS IN THE FORECAST FOR TUESDAY
FOR NOW BUT CONFIDENCE IS LOW...AS THE 00Z GFS AND EURO SHOW THE
WESTERN EDGE OF THE PRECIP SHIELD BARELY REACHING THE EASTERN
FORECAST AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 737 AM EDT FRI APR 20 2012
SOME MVFR CONDITIONS AND RAIN TODAY AS LOW PRESSURE MOVES THROUGH.
IFR IS POSSIBLE AT TIMES THIS AFTERNOON WITH CEILINGS BELOW 1000
FEET AGL. THE RAIN SHOULD MOVES EAST THIS AFTERNOON THEN NORTH
WINDS WILL GUST TO 20 KNOTS OR MORE THROUGH THE AFTERNOON. SOME
SLOW CLEARING SHOULD DEVELOP LATER TONIGHT AS THE LOW MOVES AWAY.
&&
.MARINE...
ISSUED AT 1210 PM EDT FRI APR 20 2012
KEEPING GALE WARNING IN THE FORECAST. AREAS SOUTH OF MUSKEGON MAY
SEE SUSTAINED WINDS OF 20 TO 30 KNOTS...BUT FREQUENT GUSTS ABOVE
35 KNOTS WILL REMAIN POSSIBLE.
&&
.HYDROLOGY...
ISSUED AT 400 AM EDT FRI APR 20 2012
MORE SHOWERS ON THE WAY FOR LATER THIS MORNING INTO THE AFTERNOON
WITH QPF AMOUNTS UNDER A HALF AN INCH. THIS WILL NOT BE ENOUGH TO
RESULT IN ANY SIGNIFICANT HYDRO ISSUES WITH DRY WX ALSO ANTICIPATED
TONIGHT THROUGH THE WEEKEND INTO EARLY NEXT WEEK.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...GALE WARNING UNTIL 10 PM EDT THIS EVENING FOR LMZ844>849.
&&
$$
UPDATE...TJT
SYNOPSIS...LAURENS
SHORT TERM...LAURENS
LONG TERM...OSTUNO
AVIATION...OSTUNO
HYDROLOGY...LAURENS
MARINE...TJT
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
133 PM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD INTO THE AREA
SATURDAY NIGHT AND THEN WEAKEN SUNDAY. A SURFACE LOW AND UPPER LOW WILL
MOVE SOUTH TO NORTH OVER THE EASTERN UNITED STATES EARLY NEXT WEEK
AND THIS WILL AFFECT THE WEATHER ESPECIALLY OVER NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FORECAST IN REASONABLE SHAPE THIS AFTERNOON WITH INCREASING MID
AND HIGH CLOUDS ACROSS THE AREA. CU DEVELOPING ACROSS SOUTHERN
OHIO AND EXPECTING CU FIELD TO CONTINUE EXPANDING NORTHWARD. LINE
OF RAINFALL ALONG THE FRONT WELL TO THE WEST HAS MADE LITTLE
PROGRESS DURING THE MORNING HOURS. WILL LEAVE POPS ALONG FOR THE
FAR WEST WITH INCREASING CHC POPS LATE AFTERNOON. EXPECTING MUCH OF
THE AREA TO REMAIN DRY THROUGH THE AFTERNOON AND EARLY EVENING
WITH EXCEPTION OF THE FAR WEST. TEMPS LOOK REASONABLE. PREVIOUS
DISCUSSION BELOW.
THE ISSUE FOR THIS AFTERNOON IS THE TIMING OF THE PRECIPITATION. THE
MODELS AND CURRENT CONDITIONS INDICATE THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE VERY CLOSE TO THE FRONT AND BEHIND IT. THE
FRONT IS EXPECTED TO BE FROM TOL TO FDY AROUND 20Z...CLE TO MFD AT
00Z AND ERI TO YNG BY 03Z. THE HRRR MODEL IS TRYING TO INDICATE SOME
SHOWERS DEVELOPING WAY AHEAD OF THE FRONT. MOST OF THE MODELS ARE
NOT INDICATING THIS...SO PLAYED THE FORECAST THAT WAY. SPC HAS SOME
OF THE AREA IN SEE TEXT FOR POSSIBLE SEVERE THUNDERSTORMS. EXPECTING
A FAIR AMOUNT OF CUMULUS CLOUDS THIS AFTERNOON...WE SHOULD HAVE SOME
SUNSHINE TO HELP INCREASE THE CAPES TOO MUCH. WILL MENTION IN THE HWO
STRONG TO AN ISOLATED SEVERE THUNDERSTORM COULD BE POSSIBLE. THE
BEST CHANCE FOR THUNDERSTORMS WILL BE WITHIN A FEW HOURS OF
FRONTAL PASSAGE. WITH THE SOUTHWEST FLOW AND SOME SUNSHINE WENT
TOWARD THE WARMEST GUIDANCE. ATTM WITH NOT 100% SUNSHINE WE SHOULD
NOT BREAK ANY RECORDS...THE RECORD HIGHS FOR TODAY ARE IN THE
LOWER TO MID 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
THE GFS/ECMWF HANG UNTO THE SHOWERS MUCH LONGER THAN THE OTHER
MODELS. THIS SEEMS REASONABLE WITH A FAIR AMOUNT OF OMEGA AND THE
UPPER TROF MOVING THROUGH TONIGHT AND SATURDAY. HIGH PRESSURE
RIDGE TRIES TO BUILD IN SATURDAY NIGHT AND WEAKEN BY SUNDAY...SO
SATURDAY NIGHT AND SUNDAY SHOULD BE DRY. MAY HAVE TO WORRY ABOUT
SOME FROST SATURDAY NIGHT IF THE WINDS DECREASE ENOUGH AND THE
CLOUDS COVER IS NOT TOO THICK. THE BEST CHANCE FOR DECREASING
CLOUDS WILL BE NORTHWEST OHIO. WITH SOME UNCERTAINTY DID NOT
MENTION FROST ATTM IN THE GRIDS/ZONES...ONLY THE HWO.
SUNDAY NIGHT THROUGH MONDAY NIGHT ARE INTERESTING WITH THE SURFACE LOW
AND UPPER LOW MOVING SOUTH TO NORTH OVER THE EASTERN UNITED
STATES. INTRODUCING CHANCE POPS OVER THE EASTERN PORTION OF THE
FORECAST AREA AND WITH THE AIR COLD ENOUGH A CHANCE OF RAIN OR
SNOW. NORTHWEST OHIO SHOULD REMAIN MAINLY DRY FROM THE
SYSTEM...THIS WILL HAVE TO BE WATCHED.
TENDED ON THE COOLER SIDE FOR THE TEMPERATURES.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A LOT OF UNCERTAINTY FROM TUESDAY ONWARD WITH THE FORECAST. TUESDAY
WILL DEPEND ON WHAT ENDS UP HAPPENING WITH THE EAST COAST LOW THAT
IS FORECAST TO CROSS NEW ENGLAND. HOW MUCH COLD/COOL AIR WILL BE
DRAWN SOUTHWARD WITH THIS. WITH A COUPLE RUNS WITH THIS GENERAL
SOLUTION HAVE LOWERED HIGH TEMPS ON TUESDAY AND WEDNESDAY AND THEY
WILL BE SITTING 5 TO 10 DEGREES BELOW NORMAL. THERE IS A LOT OF
SWING IN WHICH WAY THIS WILL TURN OUT. EVENTUALLY TOWARD MID WEEK WE
WILL BE IMPROVING AS WE START TO GET SOME RIDGING BUILD TOWARD THE
AREA.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
THE COLD FRONT OVER EASTERN IN HAS MADE ONLY SLOW PROGRESS TODAY. A
BAND OF PRECIP REMAINS JUST TO THE WEST OF THE FRONT. NEW MODELS
SUGGEST THE FRONT WILL MAKE IT TO KTOL AND KFDY TOWARD 00Z WITH
PRECIP FOLLOWING SHORTLY AFTER. WILL TRY TO TIME THESE FEATURES
ACROSS THE REMAINDER OF THE AREA THIS EVENING. EXPECT CIGS TO DIP
TO MVFR AN HOUR OR TWO AFTER THE FROPA AND LIKELY TO IFR AN HOUR
OR TWO AFTER THAT. MUCH OF THE AREA WILL THEN REMAIN NO BETTER
THAN MVFR THROUGH THE END OF THE TAF PERIOD. IT IS POSSIBLE THAT
KTOL AND KFDY COULD JUMP TO VFR LATE. MOST AREAS SHOULD SEE A 4 TO
6 HOUR PERIOD OF MAINLY LIGHT PRECIP. THERE IS AN OUTSIDE SHOT FOR
SOME THUNDER IN NW OH BUT THE REMAINDER OF THE AREA WILL SEE JUST
RAIN. GUSTY SW FLOW WILL BECOME W AND THEN NW BEHIND THE FRONT.
SOME GUSTS TO 25 KNOTS POSSIBLE FOR SEVERAL HOURS BEHIND THE
FROPA.
.OUTLOOK...NON VFR LIKELY FRIDAY NIGHT INTO SATURDAY MORNING AND
AGAIN FOR THE EAST MONDAY INTO TUESDAY.
&&
.MARINE...
COLD FRONT TO COME ACROSS THE LAKE THIS EVENING. SOUTHERLY FLOW
ACROSS A STABLE LAKE WILL KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA
FOR TODAY. ENOUGH POST-FRONTAL WIND TO MAKE FOR A CHOPPY NEARSHORE
LATE TONIGHT THROUGH SATURDAY MORNING...AND A SMALL CRAFT ADV WILL
LIKELY BE NEEDED THEN. HIGH PRESSURE THEN SETTLES OVER THE NORTHERN
PLAINS/WESTERN LAKES INTO EARLY NEXT WEEK WHILE AN EAST COAST LOW
TRACKS TOWARD AND ACROSS NEW ENGLAND. THIS WILL AT LEAST TIGHTEN UP
THE GRADIENT AND WILL LIKELY HAVE ANOTHER PERIOD OF SMALL CRAFT
CONDITIONS FROM MONDAY INTO TUESDAY. NORTHERLY FLOW THIS WEEKEND AND
DEPENDING ON TRACK OF THE EAST COAST LOW...POSSIBLY BACKING TO
NORTHWEST FOR EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...ABE/KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...KUBINA
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1256 PM EDT FRI APR 20 2012
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. A RIDGE OF HIGH PRESSURE WILL TRY TO BUILD INTO THE AREA
SATURDAY NIGHT AND THEN WEAKEN SUNDAY. A SURFACE LOW AND UPPER LOW WILL
MOVE SOUTH TO NORTH OVER THE EASTERN UNITED STATES EARLY NEXT WEEK
AND THIS WILL AFFECT THE WEATHER ESPECIALLY OVER NORTHEAST OHIO AND
NORTHWEST PENNSYLVANIA.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
FORECAST IN REASONABLE SHAPE THIS AFTERNOON WITH INCREASING MID
AND HIGH CLOUDS ACROSS THE AREA. CU DEVELOPING ACROSS SOUTHERN
OHIO AND EXPECTING CU FIELD TO CONTINUE EXPANDING NORTHWARD. LINE
OF RAINFALL ALONG THE FRONT WELL TO THE WEST HAS MADE LITTLE
PROGRESS DURING THE MORNING HOURS. WILL LEAVE POPS ALONG FOR THE
FAR WEST WITH INCREASING CHC POPS LATE AFTERNOON. EXPECTING MUCH OF
THE AREA TO REMAIN DRY THROUGH THE AFTERNOON AND EARLY EVENING
WITH EXCEPTION OF THE FAR WEST. TEMPS LOOK REASONABLE. PREVIOUS
DISCUSSION BELOW.
THE ISSUE FOR THIS AFTERNOON IS THE TIMING OF THE PRECIPITATION. THE
MODELS AND CURRENT CONDITIONS INDICATE THAT THE BEST CHANCE FOR
PRECIPITATION WILL BE VERY CLOSE TO THE FRONT AND BEHIND IT. THE
FRONT IS EXPECTED TO BE FROM TOL TO FDY AROUND 20Z...CLE TO MFD AT
00Z AND ERI TO YNG BY 03Z. THE HRRR MODEL IS TRYING TO INDICATE SOME
SHOWERS DEVELOPING WAY AHEAD OF THE FRONT. MOST OF THE MODELS ARE
NOT INDICATING THIS...SO PLAYED THE FORECAST THAT WAY. SPC HAS SOME
OF THE AREA IN SEE TEXT FOR POSSIBLE SEVERE THUNDERSTORMS. EXPECTING
A FAIR AMOUNT OF CUMULUS CLOUDS THIS AFTERNOON...WE SHOULD HAVE SOME
SUNSHINE TO HELP INCREASE THE CAPES TOO MUCH. WILL MENTION IN THE HWO
STRONG TO AN ISOLATED SEVERE THUNDERSTORM COULD BE POSSIBLE. THE
BEST CHANCE FOR THUNDERSTORMS WILL BE WITHIN A FEW HOURS OF
FRONTAL PASSAGE. WITH THE SOUTHWEST FLOW AND SOME SUNSHINE WENT
TOWARD THE WARMEST GUIDANCE. ATTM WITH NOT 100% SUNSHINE WE SHOULD
NOT BREAK ANY RECORDS...THE RECORD HIGHS FOR TODAY ARE IN THE
LOWER TO MID 80S.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
THE GFS/ECMWF HANG UNTO THE SHOWERS MUCH LONGER THAN THE OTHER
MODELS. THIS SEEMS REASONABLE WITH A FAIR AMOUNT OF OMEGA AND THE
UPPER TROF MOVING THROUGH TONIGHT AND SATURDAY. HIGH PRESSURE
RIDGE TRIES TO BUILD IN SATURDAY NIGHT AND WEAKEN BY SUNDAY...SO
SATURDAY NIGHT AND SUNDAY SHOULD BE DRY. MAY HAVE TO WORRY ABOUT
SOME FROST SATURDAY NIGHT IF THE WINDS DECREASE ENOUGH AND THE
CLOUDS COVER IS NOT TOO THICK. THE BEST CHANCE FOR DECREASING
CLOUDS WILL BE NORTHWEST OHIO. WITH SOME UNCERTAINTY DID NOT
MENTION FROST ATTM IN THE GRIDS/ZONES...ONLY THE HWO.
SUNDAY NIGHT THROUGH MONDAY NIGHT ARE INTERESTING WITH THE SURFACE LOW
AND UPPER LOW MOVING SOUTH TO NORTH OVER THE EASTERN UNITED
STATES. INTRODUCING CHANCE POPS OVER THE EASTERN PORTION OF THE
FORECAST AREA AND WITH THE AIR COLD ENOUGH A CHANCE OF RAIN OR
SNOW. NORTHWEST OHIO SHOULD REMAIN MAINLY DRY FROM THE
SYSTEM...THIS WILL HAVE TO BE WATCHED.
TENDED ON THE COOLER SIDE FOR THE TEMPERATURES.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
A LOT OF UNCERTAINTY FROM TUESDAY ONWARD WITH THE FORECAST. TUESDAY
WILL DEPEND ON WHAT ENDS UP HAPPENING WITH THE EAST COAST LOW THAT
IS FORECAST TO CROSS NEW ENGLAND. HOW MUCH COLD/COOL AIR WILL BE
DRAWN SOUTHWARD WITH THIS. WITH A COUPLE RUNS WITH THIS GENERAL
SOLUTION HAVE LOWERED HIGH TEMPS ON TUESDAY AND WEDNESDAY AND THEY
WILL BE SITTING 5 TO 10 DEGREES BELOW NORMAL. THERE IS A LOT OF
SWING IN WHICH WAY THIS WILL TURN OUT. EVENTUALLY TOWARD MID WEEK WE
WILL BE IMPROVING AS WE START TO GET SOME RIDGING BUILD TOWARD THE
AREA.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
VFR THROUGH DUSK WITH INTERVALS OF MID/HIGH CLOUDS. SHOULD
DEVELOP SOME 5K CU FOR THIS AFTERNOON. GUSTS WILL PICK UP LATE
MORNING AND WILL BE AROUND 25 KNOTS TODAY...WITH A FEW 30 KNOT
GUSTS POSSIBLE. THE THE BULK OF THE SHOWERS/RAIN WILL BE
IMMEDIATELY BEHIND THE FRONT TO CROSS THE AREA LATE THIS AFTERNOON
AND EVENING. THERE IS SOME CHANCE OF A FEW ISOLATED SHRA/TS
DEVELOPING AHEAD OF THE FRONT WEST OF CLE/MFD IN PEAK
HEATING...BUT FOCUSED TAFS ON THE MORE WIDESPREAD CONDITIONS
BEHIND THE FRONT. WILL HAVE TO WATCH THE TIMING OF THE FRONT AS IT
APPEARS THAT IT WILL BE SLOWING AS IT MOVES EAST. DEFINITE
MVFR...WITH GOOD CHANCES OF IFR TOO. EMBEDDED THUNDER ALSO
POSSIBLE AT LEAST INITIALLY/EARLY. RAIN WILL TAKE MOST OF THE
NIGHT TO GET THROUGH CLE AND INTO SATURDAY MORNING FURTHER EAST.
WINDS TO COME AROUND TO THE NORTH OVERNIGHT.
.OUTLOOK...NON VFR LIKELY FRIDAY NIGHT INTO SATURDAY MORNING AND
AGAIN FOR THE EAST MONDAY INTO TUESDAY.
&&
.MARINE...
COLD FRONT TO COME ACROSS THE LAKE THIS EVENING. SOUTHERLY FLOW
ACROSS A STABLE LAKE WILL KEEP CONDITIONS BELOW SMALL CRAFT CRITERIA
FOR TODAY. ENOUGH POST-FRONTAL WIND TO MAKE FOR A CHOPPY NEARSHORE
LATE TONIGHT THROUGH SATURDAY MORNING...AND A SMALL CRAFT ADV WILL
LIKELY BE NEEDED THEN. HIGH PRESSURE THEN SETTLES OVER THE NORTHERN
PLAINS/WESTERN LAKES INTO EARLY NEXT WEEK WHILE AN EAST COAST LOW
TRACKS TOWARD AND ACROSS NEW ENGLAND. THIS WILL AT LEAST TIGHTEN UP
THE GRADIENT AND WILL LIKELY HAVE ANOTHER PERIOD OF SMALL CRAFT
CONDITIONS FROM MONDAY INTO TUESDAY. NORTHERLY FLOW THIS WEEKEND AND
DEPENDING ON TRACK OF THE EAST COAST LOW...POSSIBLY BACKING TO
NORTHWEST FOR EARLY NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...ABE/KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
125 PM CDT FRI APR 20 2012
.DISCUSSION...NOTE AVIATION DISCUSSION BELOW.
&&
.AVIATION...COMBINATION OF MVFR/VFR CEILINGS ANTICIPATED IN
ADVANCE OF A COLD FRONT EXPECTED TO MOVE ACRS SOUTH TEXAS THIS
AFTN AND OFFSHORE BY EVENING/EARLY TONIGHT. IN ADVANCE OF/ALONG
FRONT...ISOLD/SCT IFR CONDITIONS EXPECTED NEAR/DRG SHOWER/
THUNDERSTORM ACTIVITY. VFR CONDITIONS ARE EXPECTED AFTER AROUND
02Z OVER LAND WITH MODERATE NORTH/NORTHEAST WIND. EXPECT WIND TO
BECOME LGT OVER LAND BY 06Z SAT...YET INCREASE TO MODERATE/BREEZY
OVER LAND GENERALLY EAST OF US281 BY MID MORNING SAT.
&&
.PREV DISCUSSION... /ISSUED 627 AM CDT FRI APR 20 2012/
DISCUSSION...UPDATED FOR 12Z AVIATION.
AVIATION...CLOUDS WILL BEGIN TO BUILD IN THIS MORNING AHEAD OF AN
APPROACHING COLD FRONT. THIS FRONT WILL PUSH THROUGH THE TAF SITES
THIS AFTERNOON WITH THUNDERSTORM CHANCES JUST AHEAD OF AND ALONG
THE FRONT. SOME STORMS...ESPECIALLY FOR EASTERN SITES MAY BE
SEVERE THIS EVENING. GUSTY NORTHERLY WINDS ARE EXPECTED TO DEVELOP
BEHIND THE FRONT AND LINGER OVERNIGHT. VFR CONDITIONS WILL RETURN
FOR SATURDAY.
PREV DISCUSSION... /ISSUED 416 AM CDT FRI APR 20 2012/
SHORT TERM (TODAY THROUGH SATURDAY)...MAIN FORECAST CONCERN IS
WITH THUNDER AND SEVERE POTENTIAL TODAY. SURFACE LOW CURRENTLY
OVER NORTHERN ILLINOIS WITH COLD FRONT DRAPED INTO WEST TEXAS
WILL PROGRESS EASTWARD TODAY. AHEAD OF THE FRONT SOUTH TO
SOUTHEAST SURFACE WINDS AND SOUTH TO SOUTHWEST WINDS AT H850 WILL
ALLOW FOR GOOD HEATING TODAY. H850 WINDS WILL ALSO KEEP A PRETTY
STRONG CAP IN PLACE FOR MUCH OF THE DAY...HAMPERING PRECIPITATION.
ANYTHING THAT WOULD DEVELOP THIS MORNING AND EARLY AFTERNOON
SHOULD JUST REMAIN SHOWER ACTIVITY. THE FRONT MOVES IN BY MID
AFTERNOON WIPING OUT THE CAP AND BRINGING A BRIEF WINDOW FOR
SEVERE WEATHER POTENTIAL. MOST MODELS ARE PEAKING CAPE ACROSS THE
AREA AROUND 1500-2000 J/KG THIS AFTERNOON...ALTHOUGH THE RUC AND
SOME MESO MODELS ARE A BIT HIGHER THAN THIS...ESPECIALLY EAST.
CONSENSUS FOR CONVECTIVE INITIATION SEEMS TO BE IN THE 20-21Z TIME
FRAME ALONG THE COLD FRONT WHERE CIN RAPIDLY DECREASES. LAPSE
700-500 LAPSE RATES LOOK FAVORABLE AND LI VALUES DECREASE TO AS
MUCH AS -8 DEPENDING ON THE MODEL. THE BIGGEST DETERRENT THOUGH MAY
BE THE SOUTHWESTERLY 850 MB WINDS. THIS COULD POTENTIALLY MAKE THE
CAP STRONG ENOUGH TO NOT ERODE BEFORE THE UPPER TROUGH MOVES
THROUGH...AND IT COULD ALSO BRING TOO MUCH DRY AIR IN...DEPENDING
ON THE DEPTH OF THESE SOUTHWEST WINDS. ADDITIONALLY...PWAT VALUES
ARE LESS THAN IMPRESSIVE FOR THE ENTIRE AREA...WITH MAINLY 1 TO
1.5 INCH VALUES EXPECTED.
WHILE THE ENTIRE FORECAST AREA HAS THE CHANCE TO SEE SEVERE
WEATHER...MAINLY A WIND AND HAIL THREAT...THE BEST CHANCE WILL BE
IN THE NORTHEAST PORTION OF THE FORECAST AREA...AND BETWEEN 21 AND
00Z.
THE UPPER TROUGH HANGS BACK A BIT, BUT SHOULD STILL MOVE
THROUGH BETWEEN 00 AND 06Z QUICKLY ENDING PRECIP CHANCES ACROSS
THE AREA. ONCE THE UPPER TROUGH GETS OUT OF HERE PLEASANT...BUT
BREEZY CONDITIONS WILL FILTER IN. TEMPERATURES SHOULD COOL NICELY
OVERNIGHT FRIDAY NIGHT INTO SATURDAY MORNING WITH TEMPS DECREASING
INTO THE 50S FOR MUCH OF THE AREA. SATURDAY LOOKS TO WARM BACK
INTO THE UPPER 70S AND 80S...BUT WITH MUCH LOWER DEWPOINTS.
MARINE...BEHIND THE COLD FRONT FRIDAY NIGHT STRONG OFFSHORE FLOW
WILL DEVELOP. WITH WARM SURFACE WATER TEMPERATURES GUSTS SHOULD
MIX DOWN PRETTY EASILY. THIS WILL LIKELY BRING NEAR GALE FORCE
GUSTS TO THE AREA BETWEEN 06Z AND 18Z SATURDAY. WILL HOLD OFF ON
ISSUING A GALE WATCH AT THIS TIME...BUT ONE MAY BE NEEDED LATER
TODAY. AT LEAST A SMALL CRAFT ADVISORY IS LIKELY.
LONG TERM (SATURDAY NIGHT THROUGH FRIDAY)...UPPER LEVEL TROUGH WILL
BE EAST OF THE AREA TO START THE EXTENDED PART OF THE FORECAST.
DRIER AIR WILL BE ENTRENCHED OVER SOUTH TEXAS AS PRECIPITABLE WATER
VALUES FALL BELOW 0.75 INCHES. WITH WINDS BECOMING LIGHTER INLAND
AND THE DRY AIR...ANTICIPATE DECENT RADIATIONAL COOLING SATURDAY
NIGHT WITH TEMPS FALLING INTO THE LOWER/MID 50S ACROSS MUCH OF THE
REGION. A DRY NORTHWEST FLOW ALOFT WILL PREVAIL INTO EARLY NEXT WEEK
AS UPPER LEVEL RIDGE BECOMES ESTABLISHED ACROSS THE ROCKIES. SURFACE
HIGH WILL SHIFT TO THE EAST ON TUESDAY WITH ONSHORE FLOW RETURNING.
TEMPS WILL MODERATE THROUGH THE WEEK...WITH LOWER 90S ACROSS THE
WEST TO LOWER/MID 80S NEAR THE COAST WEDNESDAY THROUGH FRIDAY.
LATEST RUN OF THE GFS BREAKS THE UPPER RIDGE DOWN ON THURSDAY BUT
THE EURO KEEPS UPPER TROUGH OUT WEST THROUGH THE PERIOD. FORECAST
WILL CONTINUE TO FAVOR AMPLIFIED UPPER RIDGE SOLUTION FOR THE TIME
BEING. NO SIGNIFICANT CHANGES MADE TO THE EXTENDED.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 58 78 53 82 61 / 30 0 0 0 0
VICTORIA 54 76 50 79 57 / 30 0 0 0 0
LAREDO 63 85 58 89 61 / 10 0 0 0 0
ALICE 55 81 52 83 57 / 20 0 0 0 0
ROCKPORT 60 79 57 78 62 / 40 0 0 0 0
COTULLA 55 82 50 85 57 / 10 0 0 0 0
KINGSVILLE 58 79 52 83 59 / 30 0 0 0 0
NAVY CORPUS 62 78 61 78 65 / 40 0 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
WC/87...SHORT TERM
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
104 PM CDT FRI APR 20 2012
.UPDATE...
FOR SEVERE THUNDERSTORM WATCH 184.
&&
.DISCUSSION...
ISOLATED ELEVATED CONVECTION HAS BEGUN TO DEVELOP ACROSS EASTERN
PORTIONS OF THE CWA. ADDITIONAL DESTABILIZATION IS EXPECTED
THROUGH THE AFTERNOON HOURS ACROSS AREAS GENERALLY SOUTHEAST OF
THE I-35 CORRIDOR...WHERE ISOLATED SEVERE THUNDERSTORMS WITH LARGE
HAIL AND DAMAGING WINDS ARE POSSIBLE. SEVERE THUNDERSTORM WATCH
NUMBER 184 IS IN EFFECT FOR ERN/SERN PORTIONS OF THE CWA UNTIL 8
PM.
&&
.PREV DISCUSSION... /ISSUED 1210 PM CDT FRI APR 20 2012/
AVIATION...
COLD FRONT APPROACHING THE I-35 CORRIDOR LATE THIS MORNING WITH
DEVELOPING LINE OF SHRA/TSRA JUST BEHIND THE FRONT MOVING EASTWARD
AT 30 KNOTS. LINE OF CONVECTION WILL INCREASE IN INTENSITY AS IT
MOVES OVER I-35 OVER NEXT COUPLE HOURS AND THEN ON EAST OF I-35
DURING THE AFTERNOON AND EARLY EVENING/01Z. THERE REMAINS A SLIGHT
RISK OF SEVERE STORMS GENERALLY EAST OF I35/I37 THIS AFTERNOON
WITH LARGE HAIL/DAMAGING WINDS(1+ INCH/50+ KNOTS). BRIEF IFR
CONDITIONS MAINLY ASSOCIATED WITH THE SHRA/TSRA ALONG...OTHERWISE
BECOMING VFR CONDITIONS BEHIND THE FRONT AS DRY NLY WINDS OF 10-20
KNOTS DEVELOP. CLEARING-PREVAILING VFR CONDITIONS TONIGHT AND SATURDAY
BEHIND THE COLD FRONT AS IT CONTINUES SEWD TO JUST OFF THE MIDDLE
TX COAST BY 00Z. NLY WINDS OF 10-20 KNOTS PREVAILING TONIGHT AND
SATURDAY.
PREV DISCUSSION... /ISSUED 1055 AM CDT FRI APR 20 2012/
DISCUSSION...
SURFACE WINDS HAVE ALREADY BEGUN TO SHIFT TO THE NORTH ACROSS THE
CWA...BUT THE TRUE COLD FRONT IS STRETCHED ACROSS CENTRAL TEXAS/HILL
COUNTRY. THE FRONT IS STILL EXPECTED TO REACH THE I-35 CORRIDOR
AT AROUND NOON. AS THE FRONTAL BOUNDARY APPROACHES...SFC PRESSURE
GRADIENTS WILL TIGHTEN LEADING TO WINDS INCREASING TO 15 TO 20 MPH
WITH GUSTS OF 25 TO 30 MPH. SCATTERED SHOWERS WILL CONTINUE THROUGH
THIS MORNING AHEAD OF THE FRONT...WITH A BROKEN LINE OF SHOWERS
AND THUNDERSTORMS ALONG THE FRONTAL BOUNDARY. HAVE EXTENDED POPS A
LITTLE FURTHER WEST AND SOUTHWEST GIVEN THE CURRENT DEVELOPMENT
ALONG THE TAIL-END OF THE FRONT. WINDS AND WIND GUSTS WERE ALSO
INCREASED THROUGH THIS EVENING PER 12Z NAM/15Z RUC SUGGESTIONS AND
16Z SFC OBS. OTHERWISE HAVE ONLY MADE MINOR ADJUSTMENTS TO ACCOUNT
FOR HOURLY TRENDS.
PREV DISCUSSION... /ISSUED 713 AM CDT FRI APR 20 2012/
AVIATION...
AT 12Z COLD FRONT EXTENDED FROM COMANCHE TO BROWNWOOD TO SONORA
MOVING SOUTHEAST. THE COLD FRONT WILL PUSH INTO THE HILL COUNTRY
BY LATE MORNING AND PUSH RAPIDLY SOUTH ALONG THE I-35 CORRIDOR BY
EARLY AFTERNOON. AN UPPER DISTURBANCE INTERACTING WITH THE FRONT
WILL PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
A FEW STORMS MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS
THIS AFTERNOON ALONG AND EAST OF THE I-35 CORRIDOR...INCLUDING THE
KSAT...KSSF AND KAUS TERMINALS. I-35 CORRIDOR TERMINALS MVFR AND
BRIEF IFR CIGS EARLY THIS MORNING BECOMING MVFR CIGS BY LATE
MORNING WITH SCTD SHOWERS LOCALLY LOWERING VSBYS. LOW VFR CIGS
BY LATE MORNING WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING LATE MORNING THROUGH MID AFTERNOON LOCALLY LOWERING
CIGS AND VSBYS. DECREASING CLOUDS LATE AFTERNOON BECOMING MOSTLY
CLEAR BY EVENING. I-35 CORRIDOR WINDS LIGHT AND VARIABLE TO LIGHT
SOUTHEAST TO EAST BECOMING NORTH 15 TO 20 KTS BY LATE MORNING.
NORTH WINDS LOWERING TO AROUND 10 KTS BY MIDNIGHT. KDRT TERMINAL
VARIABLE VFR CLOUDS BECOMING CLEAR THIS EVENING. EAST WIND 5 TO 10
KTS BECOMING NORTHWEST NEAR 15 KTS BY LATE MORNING. KDRT WINDS
BECOMING LIGHT NORTHEAST BY DARK.
PREV DISCUSSION... /ISSUED 347 AM CDT FRI APR 20 2012/
DISCUSSION...
AT 08Z THE COLD FRONT EXTENDED FROM PECOS TO SAN ANGELO TO SHERMAN
MOVING SOUTHEASTWARD. THE FRONT WILL ENTER THE HILL COUNTRY AROUND
9 AM AND WILL BE LOCATED ALONG THE I-35 CORRIDOR AROUND NOONTIME.
ISOLATED WARM SECTOR SHOWERS WILL OCCUR THIS MORNING UNDER THE CAP
IN ADVANCE OF THE FROPA AND LAGGING UPPER LEVEL TROF. THE SPC DAY
ONE CONVECTIVE OUTLOOK HAS OUR CWFA IN THE SLIGHT RISK AREA ALONG
AND EAST OF A LINE FROM LEXINGTON TO SAN MARCOS TO SAN ANTONIO TO
DILLEY AND WE AGREE WITH THIS DELINEATION. CONVECTION ALONG AND
BEHIND THE SHALLOW FRONTAL BOUNDARY WILL INCREASE AS THE SFC
FRONT NEARS THE I-35 CORRIDOR. THE PRIMARY SEVERE WEATHER THREATS
WILL BE LARGE HAIL AND DAMAGING WINDS ASSOCIATED WITH ACCELERATING
BOW SEGMENTS. THE SAN ANTONIO AND AUSTIN METRO AREAS ARE ON THE
WESTERN EDGE OF THE SLIGHT RISK AREA WHERE THE SEVERE STORMS MAY
FIRST INITIATE. THE CONVECTIVE COMPLEX WILL EXIT OUR SOUTHEAST
COUNTIES AROUND MIDNIGHT. HIGHS THIS AFTERNOON WILL RANGE FROM THE
MID 70S ACROSS OUR NORTHEAST COUNTIES TO UPPER 80S SOUTHWEST.
A DRY AIRMASS WILL OVERSPREAD SOUTH CENTRAL TEXAS IN THE WAKE OF
TODAYS FROPA. THIS WILL RESULT IN COOL NIGHTS FOLLOWED BY MILD
AFTERNOONS OVER THE WEEKEND. OVERNIGHT LOWS WILL FALL INTO THE
MID TO UPPER 40S ACROSS THE HILL COUNTRY. AFTERNOON HIGHS WILL BE
AROUND SEASONAL NORMALS.
A DRY NORTHWEST FLOW ALOFT WILL PREVAIL THRU THE MIDDLE OF NEXT
WEEK KEEPING SOUTH CENTRAL TEXAS RAIN FREE. THE UPPER LEVEL RIDGE
AXIS OVER NORTHERN MEXICO/SOUTHWESTERN U.S. WILL SHIFT EASTWARD
INTO TEXAS BY THE END OF NEXT WEEK. LOW LEVEL MOISTURE WILL BEGIN
TO RETURN TO SOUTH CENTRAL TEXAS TUESDAY NIGHT INTO WEDNESDAY
MORNING AS THE SFC HIGH MOVES OVER THE NORTHERN GULF OF MEXICO.
PATCHY MORNING FOG WILL BE POSSIBLE SOUTH AND EAST OF THE I-35
CORRIDOR WEDNESDAY MORNING AS THE AIRMASS BEGINS ITS TRANSITION
FROM CONTINENTAL TO GULF/MARITIME.
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE SATURDAY AFTERNOON
ACROSS THE EDWARDS PLATEAU AND RIO GRANDE PLAINS DUE TO LOW
RELATIVE HUMIDITIES. MINIMUM AFTERNOON RELATIVE HUMIDITIES WILL
FALL BELOW 25 PERCENT WEST OF A LINE FROM MOUNTAIN HOME TO HONDO
TO COTULLA WITH AROUND 20 PERCENT EXPECTED ALONG THE RIO GRANDE.
20-FOOT WINDS WILL BE NORTHERLY AT 5 TO 10 MPH.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 76 53 76 53 83 / 50 10 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 75 50 76 48 82 / 50 10 0 0 0
NEW BRAUNFELS MUNI AIRPORT 78 53 78 49 82 / 40 10 0 0 0
BURNET MUNI AIRPORT 74 49 75 48 81 / 40 - 0 0 0
DEL RIO INTL AIRPORT 86 55 83 54 87 / 10 - 0 0 0
GEORGETOWN MUNI AIRPORT 75 47 75 47 81 / 50 10 0 0 0
HONDO MUNI AIRPORT 82 50 80 48 84 / 30 - 0 0 0
SAN MARCOS MUNI AIRPORT 76 52 77 49 82 / 40 10 0 0 0
LA GRANGE - FAYETTE REGIONAL 76 54 75 53 80 / 60 10 0 0 0
SAN ANTONIO INTL AIRPORT 79 53 78 52 82 / 30 10 0 0 0
STINSON MUNI AIRPORT 80 55 79 53 83 / 30 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...01
SYNOPTIC/GRIDS...25
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS AUSTIN/SAN ANTONIO TX
1210 PM CDT FRI APR 20 2012
.AVIATION...
COLD FRONT APPROACHING THE I-35 CORRIDOR LATE THIS MORNING WITH
DEVELOPING LINE OF SHRA/TSRA JUST BEHIND THE FRONT MOVING EASTWARD
AT 30 KNOTS. LINE OF CONVECTION WILL INCREASE IN INTENSITY AS IT
MOVES OVER I-35 OVER NEXT COUPLE HOURS AND THEN ON EAST OF I-35
DURING THE AFTERNOON AND EARLY EVENING/01Z. THERE REMAINS A SLIGHT
RISK OF SEVERE STORMS GENERALLY EAST OF I35/I37 THIS AFTERNOON
WITH LARGE HAIL/DAMAGING WINDS(1+ INCH/50+ KNOTS). BRIEF IFR
CONDITIONS MAINLY ASSOCIATED WITH THE SHRA/TSRA ALONG...OTHERWISE
BECOMING VFR CONDITIONS BEHIND THE FRONT AS DRY NLY WINDS OF 10-20
KNOTS DEVELOP. CLEARING-PREVAILING VFR CONDITIONS TONIGHT AND SATURDAY
BEHIND THE COLD FRONT AS IT CONTINUES SEWD TO JUST OFF THE MIDDLE
TX COAST BY 00Z. NLY WINDS OF 10-20 KNOTS PREVAILING TONIGHT AND
SATURDAY.
&&
.PREV DISCUSSION... /ISSUED 1055 AM CDT FRI APR 20 2012/
DISCUSSION...
SURFACE WINDS HAVE ALREADY BEGUN TO SHIFT TO THE NORTH ACROSS THE
CWA...BUT THE TRUE COLD FRONT IS STRETCHED ACROSS CENTRAL TEXAS/HILL
COUNTRY. THE FRONT IS STILL EXPECTED TO REACH THE I-35 CORRIDOR
AT AROUND NOON. AS THE FRONTAL BOUNDARY APPROACHES...SFC PRESSURE
GRADIENTS WILL TIGHTEN LEADING TO WINDS INCREASING TO 15 TO 20 MPH
WITH GUSTS OF 25 TO 30 MPH. SCATTERED SHOWERS WILL CONTINUE THROUGH
THIS MORNING AHEAD OF THE FRONT...WITH A BROKEN LINE OF SHOWERS
AND THUNDERSTORMS ALONG THE FRONTAL BOUNDARY. HAVE EXTENDED POPS A
LITTLE FURTHER WEST AND SOUTHWEST GIVEN THE CURRENT DEVELOPMENT
ALONG THE TAIL-END OF THE FRONT. WINDS AND WIND GUSTS WERE ALSO
INCREASED THROUGH THIS EVENING PER 12Z NAM/15Z RUC SUGGESTIONS AND
16Z SFC OBS. OTHERWISE HAVE ONLY MADE MINOR ADJUSTMENTS TO ACCOUNT
FOR HOURLY TRENDS.
PREV DISCUSSION... /ISSUED 713 AM CDT FRI APR 20 2012/
AVIATION...
AT 12Z COLD FRONT EXTENDED FROM COMANCHE TO BROWNWOOD TO SONORA
MOVING SOUTHEAST. THE COLD FRONT WILL PUSH INTO THE HILL COUNTRY
BY LATE MORNING AND PUSH RAPIDLY SOUTH ALONG THE I-35 CORRIDOR BY
EARLY AFTERNOON. AN UPPER DISTURBANCE INTERACTING WITH THE FRONT
WILL PRODUCE SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS.
A FEW STORMS MAY BECOME SEVERE WITH LARGE HAIL AND DAMAGING WINDS
THIS AFTERNOON ALONG AND EAST OF THE I-35 CORRIDOR...INCLUDING THE
KSAT...KSSF AND KAUS TERMINALS. I-35 CORRIDOR TERMINALS MVFR AND
BRIEF IFR CIGS EARLY THIS MORNING BECOMING MVFR CIGS BY LATE
MORNING WITH SCTD SHOWERS LOCALLY LOWERING VSBYS. LOW VFR CIGS
BY LATE MORNING WITH SCATTERED SHOWERS AND THUNDERSTORMS
DEVELOPING LATE MORNING THROUGH MID AFTERNOON LOCALLY LOWERING
CIGS AND VSBYS. DECREASING CLOUDS LATE AFTERNOON BECOMING MOSTLY
CLEAR BY EVENING. I-35 CORRIDOR WINDS LIGHT AND VARIABLE TO LIGHT
SOUTHEAST TO EAST BECOMING NORTH 15 TO 20 KTS BY LATE MORNING.
NORTH WINDS LOWERING TO AROUND 10 KTS BY MIDNIGHT. KDRT TERMINAL
VARIABLE VFR CLOUDS BECOMING CLEAR THIS EVENING. EAST WIND 5 TO 10
KTS BECOMING NORTHWEST NEAR 15 KTS BY LATE MORNING. KDRT WINDS
BECOMING LIGHT NORTHEAST BY DARK.
PREV DISCUSSION... /ISSUED 347 AM CDT FRI APR 20 2012/
DISCUSSION...
AT 08Z THE COLD FRONT EXTENDED FROM PECOS TO SAN ANGELO TO SHERMAN
MOVING SOUTHEASTWARD. THE FRONT WILL ENTER THE HILL COUNTRY AROUND
9 AM AND WILL BE LOCATED ALONG THE I-35 CORRIDOR AROUND NOONTIME.
ISOLATED WARM SECTOR SHOWERS WILL OCCUR THIS MORNING UNDER THE CAP
IN ADVANCE OF THE FROPA AND LAGGING UPPER LEVEL TROF. THE SPC DAY
ONE CONVECTIVE OUTLOOK HAS OUR CWFA IN THE SLIGHT RISK AREA ALONG
AND EAST OF A LINE FROM LEXINGTON TO SAN MARCOS TO SAN ANTONIO TO
DILLEY AND WE AGREE WITH THIS DELINEATION. CONVECTION ALONG AND
BEHIND THE SHALLOW FRONTAL BOUNDARY WILL INCREASE AS THE SFC
FRONT NEARS THE I-35 CORRIDOR. THE PRIMARY SEVERE WEATHER THREATS
WILL BE LARGE HAIL AND DAMAGING WINDS ASSOCIATED WITH ACCELERATING
BOW SEGMENTS. THE SAN ANTONIO AND AUSTIN METRO AREAS ARE ON THE
WESTERN EDGE OF THE SLIGHT RISK AREA WHERE THE SEVERE STORMS MAY
FIRST INITIATE. THE CONVECTIVE COMPLEX WILL EXIT OUR SOUTHEAST
COUNTIES AROUND MIDNIGHT. HIGHS THIS AFTERNOON WILL RANGE FROM THE
MID 70S ACROSS OUR NORTHEAST COUNTIES TO UPPER 80S SOUTHWEST.
A DRY AIRMASS WILL OVERSPREAD SOUTH CENTRAL TEXAS IN THE WAKE OF
TODAYS FROPA. THIS WILL RESULT IN COOL NIGHTS FOLLOWED BY MILD
AFTERNOONS OVER THE WEEKEND. OVERNIGHT LOWS WILL FALL INTO THE
MID TO UPPER 40S ACROSS THE HILL COUNTRY. AFTERNOON HIGHS WILL BE
AROUND SEASONAL NORMALS.
A DRY NORTHWEST FLOW ALOFT WILL PREVAIL THRU THE MIDDLE OF NEXT
WEEK KEEPING SOUTH CENTRAL TEXAS RAIN FREE. THE UPPER LEVEL RIDGE
AXIS OVER NORTHERN MEXICO/SOUTHWESTERN U.S. WILL SHIFT EASTWARD
INTO TEXAS BY THE END OF NEXT WEEK. LOW LEVEL MOISTURE WILL BEGIN
TO RETURN TO SOUTH CENTRAL TEXAS TUESDAY NIGHT INTO WEDNESDAY
MORNING AS THE SFC HIGH MOVES OVER THE NORTHERN GULF OF MEXICO.
PATCHY MORNING FOG WILL BE POSSIBLE SOUTH AND EAST OF THE I-35
CORRIDOR WEDNESDAY MORNING AS THE AIRMASS BEGINS ITS TRANSITION
FROM CONTINENTAL TO GULF/MARITIME.
FIRE WEATHER...
ELEVATED FIRE WEATHER CONDITIONS ARE POSSIBLE SATURDAY AFTERNOON
ACROSS THE EDWARDS PLATEAU AND RIO GRANDE PLAINS DUE TO LOW
RELATIVE HUMIDITIES. MINIMUM AFTERNOON RELATIVE HUMIDITIES WILL
FALL BELOW 25 PERCENT WEST OF A LINE FROM MOUNTAIN HOME TO HONDO
TO COTULLA WITH AROUND 20 PERCENT EXPECTED ALONG THE RIO GRANDE.
20-FOOT WINDS WILL BE NORTHERLY AT 5 TO 10 MPH.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 76 53 76 53 83 / 50 10 0 0 0
AUSTIN BERGSTROM INTL AIRPORT 75 50 76 48 82 / 50 10 0 0 0
NEW BRAUNFELS MUNI AIRPORT 78 53 78 49 82 / 40 10 0 0 0
BURNET MUNI AIRPORT 74 49 75 48 81 / 40 - 0 0 0
DEL RIO INTL AIRPORT 86 55 83 54 87 / 10 - 0 0 0
GEORGETOWN MUNI AIRPORT 75 47 75 47 81 / 50 10 0 0 0
HONDO MUNI AIRPORT 82 50 80 48 84 / 30 - 0 0 0
SAN MARCOS MUNI AIRPORT 76 52 77 49 82 / 40 10 0 0 0
LA GRANGE - FAYETTE REGIONAL 76 54 75 53 80 / 60 10 0 0 0
SAN ANTONIO INTL AIRPORT 79 53 78 52 82 / 30 10 0 0 0
STINSON MUNI AIRPORT 80 55 79 53 83 / 30 10 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MESOSCALE/AVIATION...01
SYNOPTIC/GRIDS...25
PUBLIC SERVICE/DATA COLLECTION...32
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
323 PM CDT FRI APR 20 2012
.SHORT TERM...TONIGHT THROUGH MONDAY
323 PM CDT FRI APR 20 2012
MAIN FORECAST CONCERNS ARE ON FROST/FREEZE POTENTIAL TONIGHT AND
RAIN SHOWER CHANCES SATURDAY THROUGH SUNDAY.
LATEST SURFACE OBSERVATIONS SHOWED AN AREA OF HIGH PRESSURE
EXTENDING FROM THE ARROWHEAD OF MINNESOTA...SOUTH ACROSS EASTERN
MINNESOTA INTO CENTRAL IOWA. LOOK FOR THE HIGH TO SHIFT EAST OVER
THE FORECAST AREA TONIGHT.
COOL HIGH PRESSURE WILL SLIDE OVER THE UPPER MISSISSIPPI RIVER
VALLEY TONIGHT WITH LIGHT AND VARIABLE WINDS EXPECTED. LOOK FOR
TEMPERATURES TO FALL INTO THE MID 20S ACROSS NORTH CENTRAL INTO
CENTRAL WISCONSIN. SLIGHTLY WARMER TEMPERATURES ARE ANTICIPATED FOR
LOCATIONS NEAR AND ALONG THE MISSISSIPPI RIVER WITH LOWS FALLING TO
AROUND FREEZING OR SLIGHTLY BELOW. LOCATIONS FURTHER WEST...ACROSS
SOUTHEAST MINNESOTA INTO NORTHEAST IOWA...LOOK FOR LOWS TO FALL INTO
THE LOWER 30S. WILL CONTINUE FREEZE WARNING ACROSS PORTIONS OF
SOUTHWEST...CENTRAL...AND NORTH CENTRAL WISCONSIN. HAVE DECIDED TO
HOIST A FROST ADVISORY FOR COUNTIES ALONG THE MISSISSIPPI RIVER
WHERE TEMPERATURES WILL FALL INTO THE LOWER 30S AND AREAS OF FROST
ARE EXPECTED. THE FROST ADVISORY WILL RUN FROM 1 AM THOUGH 8 AM
SATURDAY. IN ADDITION...SOME PATCHY FOG IS POSSIBLE ACROSS THE
AREA TONIGHT...BUT LOOKING AT SURFACE OBSERVATIONS UPSTREAM ACROSS
CENTRAL MINNESOTA INTO NORTHERN MINNESOTA...DEWPOINTS ARE FALLING
INTO THE MID 20S TO LOWER TEENS. IN ADDITION...WINDS ALOFT LOOK TO
INCREASE TONIGHT FROM JUST ABOVE THE SURFACE THROUGH 1 KFT. WILL
HAVE TO KEEP A CLOSE WATCH ON THE POTENTIAL FOR VALLEY FOG ALONG
THE MISSISSIPPI RIVER AND WISCONSIN RIVER VALLEYS. GIVEN THE DRY
NATURE OF THE AIR MASS AND WINDS INCREASING ALOFT...FEEL OVERALL
FOG COVERAGE WILL BE LIMITED. ANOTHER CONCERN IS HIGH CLOUDS
MOVING INTO THE AREA AROUND 06Z TONIGHT. WILL HAVE TO KEEP A CLOSE
WATCH ON THIS CLOUD SHIELD WITH THE POTENTIAL FOR TEMPERATURES TO
STAY JUST ABOVE FREEZING ALONG AND WEST OF THE MISSISSIPPI RIVER.
A SHORTWAVE TROUGH WILL PUSH INTO MINNESOTA EARLY ON SATURDAY WITH
SHOWERS SPREADING FROM WEST TO EAST ACROSS MINNESOTA INTO NORTHEAST
IOWA. THE BULK OF THE SHOWER ACTIVITY IS EXPECTED TO STAY WEST OF
THE MISSISSIPPI RIVER UNTIL LATE SATURDAY AFTERNOON THEN SPREAD INTO
WESTERN WISCONSIN DURING THE EARLY EVENING. FORECAST MODELS HAVE
BEEN VERY CONSISTENT WITH THIS FEATURE...BUT SOME SMALL TIMING
DIFFERENCES REMAIN. A MAJORITY OF THE GUIDANCE SIDES WITH KEEPING
THE RAIN MAINLY WEST OF THE MISSISSIPPI RIVER THROUGH LATE AFTERNOON
SO DECIDED TO LEAN THAT DIRECTION AND INCREASE PRECIPITATION
CHANCES. MOST LOCATIONS SHOULD SEE AT LEAST A FEW HUNDREDTHS OF AN
INCH OF RAINFALL OUT OF THIS SYSTEM..WITH SOME AREAS RECEIVING A
FEW TENTHS. LOOK FOR SHOWERS TO PERSIST INTO SUNDAY EVENING BEFORE
TAPERING OFF LATE IN THE NIGHT. PLAN ON HIGH TEMPERATURES IN THE
LOWER TO MIDDLE 50S. LOOK FOR OVERNIGHT LOWS TO FALL INTO THE LOWER
30S ACROSS NORTH CENTRAL WISCONSIN...AND INTO THE UPPER 30S TO LOWER
40S ACROSS NORTHEAST IOWA.
ANOTHER SHORTWAVE IS EXPECTED TO PUSH ACROSS THE REGION ON SUNDAY
AND DRAGS A FRONTAL BOUNDARY ACROSS THE FORECAST AREA. LOOK FOR
SCATTERED SHOWERS ACROSS THE AREA AS THE WAVE MOVES IN. IN
ADDITION...PLAN ON WINDS SWITCHING TO THE NORTHWEST...BECOMING GUSTY
AT TIMES ESPECIALLY UNDER ANY RAIN SHOWERS. THE STRONGEST WINDS ARE
EXPECTED ALONG AND WEST OF THE MISSISSIPPI RIVER WHERE THE PRESSURE
GRADIENT WILL BE THE TIGHTEST. PLAN ON NORTHWEST WINDS OF 10 TO 20
MPH...GUSTING TO AROUND 35 MPH UNDER THE RAIN SHOWERS. PLAN ON HIGHS
ON SUNDAY RANGING FROM THE LOWER 50S ACROSS NORTH CENTRAL WISCONSIN
TO MID TO UPPER 50S ACROSS NORTHEAST IOWA. SURFACE HIGH PRESSURE IS
EXPECTED TO SETTLE OVER THE AREA SUNDAY NIGHT INTO MONDAY PROVIDING
COOL AND QUIET CONDITIONS. LOW PRESSURE OVER THE EASTERN GREAT LAKES
WILL LIFT NORTHWARD AND RETROGRADE TOWARD HUDSON BAY. PLAN ON HIGHS
ONCE AGAIN MAINLY IN THE 50S ON MONDAY.
.LONG TERM...TUESDAY THROUGH FRIDAY
323 PM CDT FRI APR 20 2012
20.12 FORECAST MODELS IN BETTER AGREEMENT THIS RUN SHOWING A FAST
MOVING SHORTWAVE CLIPPING THE REGION TUESDAY NIGHT INTO WEDNESDAY.
THIS WAVE ALONG WITH A BAROCLINIC ZONE EDGING IN FROM THE
WEST...WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS TO THE AREA.
A DEEP UPPER LEVEL TROUGH IS EXPECTED TO DIVE INTO THE UPPER
MISSISSIPPI RIVER VALLEY THURSDAY INTO THURSDAY NIGHT BRINGING A
CHANCE OF SHOWERS TO THE AREA. THE ECMWF OFFERS A COLDER SOLUTION
OVER THE GFS THURSDAY NIGHT THROUGH FRIDAY...KEEPING A HIGH
AMPLITUDE RIDGE OVER THE CENTRAL CONUS EXTENDING NORTHWEST THROUGH
CENTRAL MANITOBA/SASKATCHEWAN. THE GFS ATTEMPTS TO SLIDE THIS RIDGE
EAST INTO THE REGION...WHICH WOULD FAVOR WARMER TEMPERATURES. GIVEN
THE MODEL DIFFERENCES DECIDED TO LEAN TOWARD A MODEL CONSENSUS
BLEND. LOOK FOR HIGH TEMPERATURES ON THURSDAY IN THE LOWER
60S...WITH LOWS FALLING INTO THE UPPER 30S TO LOWER 40S THURSDAY
NIGHT. THESE LOW COULD BE 5 DEGREES COOLER IF THE ECMWF SOLUTIONS
HOLDS. HAVE INCLUDED A CHANCE OF SHOWERS ACROSS SOUTHWEST THROUGH
CENTRAL AND NORTH CENTRAL WISCONSIN...WITH THE MAIN FORCING FROM
THE UPPER LEVEL TROUGH MOVING THROUGH THESE AREAS.
&&
.AVIATION...THROUGH 18Z SATURDAY
1232 PM CDT FRI APR 20 2012
BIGGEST CONCERN IS ON FOG POTENTIAL TONIGHT AND ITS IMPACT AT THE
TAF SITES. CLOUDS DECREASED AT TAF SITES LATE THIS MORNING...BUT
WITH COLD AIR ALOFT...CUMULUS WAS REFORMING WITH A SCT-BKN DECK.
BASES EXPECTED TO REMAIN IN THE 3K-4K FOOT RANGE THROUGHOUT THE
DAY...BEFORE DIMINISHING THIS EVENING DUE TO LOSS OF HEATING.
TRANSIENT SURFACE RIDGE BUILDS ACROSS THE AREA TONIGHT WITH WINDS
BECOMING LIGHT AND SKIES MAINLY CLEAR...AT LEAST THROUGH 06Z.
POTENTIAL EXISTS FOR SOME FOG FORMATION WITH THE RECENT
RAINS...BUT THERE ARE SOME NEGATIVE FACTORS THAT LOWERS
CONFIDENCE. THOSE NEGATIVE FACTORS ARE AN INCREASE IN HIGH LEVEL
CLOUDS AFTER 06Z...ALONG WITH THE SURFACE RIDGE PUSHING EAST WITH
WINDS BECOMING MORE SOUTHERLY. 20.12Z NAM BUFKIT SOUNDS SHOWING
WINDS STRENGTHENING ABOVE THE BOUNDARY LAYER LATE TONIGHT...WITH
THE 20.15Z RUC NOT QUITE AS AGGRESSIVE WITH THESE WINDS. FEEL
BIGGEST THEREAT FOR FOG WOULD BE AT KLSE...WHERE CLOUDS/WINDS
DELAYED IN GETTING IN THERE. THUS DID INTRODUCE BCFG IN THE TAF.
THIS WILL HAVE TO BE MONITORED CLOSELY DURING THE EVENING.
NEXT SHORTWAVE DROPS THROUGH THE FLOW SATURDAY MORNING...WITH THE
GFS/GEM SHOWING PRECIPITATION ENTERING SOUTHEAST MINNESOTA BETWEEN
15Z-18Z...WHILE NAM HOLDS IT OFF UNTIL AFTER 18Z. DID INTRODUCE
VCSH AT KRST...WITH KLSE REMAINING DRY. CEILINGS EXPECTED TO
REMAIN VFR AT BOTH SITES...ALTHOUGH LOWERING TO AROUND 8K FEET AT KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
313 PM CDT FRI APR 20 2012
WI...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR WIZ032-033-041-
054-061.
FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR WIZ017-029-034-
042>044-053-055.
MN...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR MNZ079-088-096.
IA...FROST ADVISORY FROM 1 AM TO 8 AM CDT SATURDAY FOR IAZ011-030.
&&
$$
SHORT TERM...WETENKAMP
LONG TERM...WETENKAMP
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1232 PM CDT FRI APR 20 2012
.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
333 AM CDT FRI APR 20 2012
MAIN FORECAST CONCERNS ARE ON FROST/FREEZE TONIGHT AND NEXT EXPECTED
RAIN SATURDAY/SATURDAY NIGHT.
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS
SHOWED RIDGING BUILDING UP OVER THE WESTERN U.S....TROUGHING FROM
MINNESOTA SOUTH INTO TEXAS...AND RIDGING ALONG THE EAST COAST OF THE
U.S. WITHIN THE TROUGHING...MAIN FEATURES OF NOTE INCLUDE SHORTWAVES
OVER THE EASTERN SIDE OF THE FORECAST AREA AND BACK OVER WESTERN
SOUTH DAKOTA INTO NORTHWEST NEBRASKA. THE LATTER SHORTWAVE HAS
HELPED PUSH THE LOW TO MID LEVEL FRONTOGENESIS ZONE AND DEEP
MOISTURE SEEN ON THE 00Z GRB SOUNDING EASTWARD. REGARDING THAT
FRONTOGENESIS ZONE...THIS IS EASILY SEEN IN 00Z RAOBS AT 850MB WITH
0C AT MPX...3C AT GRB AND 12C AT DVN. IN ADDITION...AN UPPER JET
STREAK OF 100-110 KT IN EASTERN ONTARIO LAST EVENING...AIDING IN
FORCING FOR PRECIPITATION ACROSS WISCONSIN...HAS BEEN PUSHED
EASTWARD BY THE SHORTWAVE. LATEST RADAR MOSAIC SHOWS JUST A LITTLE
LIGHT RAIN/SNOW IN A WEAKENING COLD CONVEYOR BELT IN CENTRAL
WISCONSIN. TO THE WEST...SUBSIDENCE AND DRYING HAS BEEN CLEARING
SKIES OUT ACROSS MINNESOTA. A SURFACE RIDGE OF HIGH PRESSURE HAS
ALSO BEEN DROPPING SOUTH INTO THE DAKOTAS AND WESTERN MINNESOTA.
FARTHER WEST...A FEW SHOWERS CONTINUE BACK OVER CENTRAL SOUTH
DAKOTA AHEAD OF THE SHORTWAVE THERE. LAST ITEM OF NOTE IS A
SHORTWAVE ON WATER VAPOR COMING INTO SOUTHERN BRITISH COLUMBIA.
TODAY AND TONIGHT...UPPER TROUGHING OVER MINNESOTA WILL SLIDE EAST
ACROSS THE THE FORECAST AREA TODAY...ALLOWING THE SURFACE RIDGE OF
HIGH PRESSURE TO BUILD INTO THE FORECAST AREA THIS EVENING. THIS
SHOULD ALLOW FOR CLEARING AND DRYING. TEMPERATURES ARE LIKELY TO NOT
END UP MUCH HIGHER THAN YESTERDAY BECAUSE 850MB TEMPS ARE -2 TO
-3C...BUT MORE SUN AND THE LACK OF RAIN WILL MAKE IT FEEL WARMER.
QUESTION TONIGHT IS FROST/FREEZE. HAVING THE SURFACE RIDGE OVER
THE AREA IN THE EVENING IS GOOD FOR GETTING COLD...BUT THERE IS AN
ISSUE LURKING UPSTREAM. THE SHORTWAVE COMING INTO SOUTHERN BRITISH
COLUMBIA MODELS SHOW TOPPING THE WESTERN U.S. RIDGE TODAY...THEN
DROPPING INTO THE EASTERN DAKOTAS BY 12Z SATURDAY. ANTICIPATING A
STREAM OF MID AND HIGH LEVEL CLOUD COVER TO SPREAD DOWNSTREAM
AHEAD OF THIS SHORTWAVE...MOVING INTO THE FORECAST AREA AFTER
MIDNIGHT. IT APPEARS LOCATIONS ACROSS SOUTHWEST INTO CENTRAL
WISCONSIN WILL STAY THE CLEAREST THE LONGEST...AND THE SURFACE
RIDGE IS EXPECTED TO STAY IN PLACE THERE TOO. THEREFORE... FEEL
THIS AREA HAS THE BEST POTENTIAL FOR FREEZE CONDITIONS WITH
AREAS/WIDESPREAD FROST. FREEZE WARNINGS NOTED IN THE WWA SECTION
BELOW. ANOTHER POTENTIAL ISSUE TO CONTEND WITH MIGHT BE FOG GIVEN
RECENT RAINS. NOT VERY CONFIDENT TO INCLUDE FOG AT THIS TIME...
EITHER FOR RADIATIONAL INDUCED OR IN THE VALLEYS...AS THERE SHOULD
BE DECENT DRYING TODAY.
SATURDAY AND SATURDAY NIGHT...SHORTWAVE OVER THE EASTERN DAKOTAS
LOOKS TO CONTINUE ITS SOUTHEASTWARD TREK DOWN THE UPPER RIDGE. THE
20.00Z NAM IS AN OUTLIER WITH ITS TRACK...MOVING INTO WISCONSIN
TONIGHT. THE 20.00Z GFS/UKMET/ECMWF ALL TAKE A FARTHER WEST TRACK
THROUGH SOUTHEAST MINNESOTA AND NORTHEAST IOWA TONIGHT WHICH SEEMS
MORE REASONABLE. ISENTROPIC LIFT ASSOCIATED WITH THE SHORTWAVE...
BEST SEEN ON 290-300K SURFACES...WILL MOVE INTO SOUTHEAST MINNESOTA
AND NORTHEAST IOWA ON SATURDAY. SHOULD EVENTUALLY SEE RAIN DEVELOP
AS LOW LEVELS MOISTEN. AFTERNOON SEEMS MOST LIKELY TO SEE RAIN.
ANOTHER FAVORABLE FORCING MECHANISM IS A 120KT UPPER JET DROPPING
DOWN INTO SOUTHWEST MINNESOTA...PLACING LOCATIONS WEST OF THE
MISSISSIPPI RIVER IN UPPER DIVERGENCE. NICE LOW TO MID LEVEL
FRONTOGENESIS/FRONTOLYSIS COUPLET SHOWS UP TOO. BOTH THE ISENTROPIC
LIFT AND UPPER JET FORCING DIMINISHES SATURDAY NIGHT...WHICH WOULD
SUGGEST PRECIPITATION SHOULD DIMINISH. THE LOW TO MID LEVEL
FRONTOGENESIS LINGERS...THOUGH...NOTED TOO BY AN INVERTED TROUGH AT
THE SURFACE LINGERING BACK INTO WESTERN MINNESOTA. THEREFORE...
SHOULD STILL SEE SOME LIGHT PRECIPITATION AFTER MIDNIGHT. GIVEN THE
STRONG FORCING SIGNALS...HAVE RAISED PRECIPITATION CHANCES
UP...ESPECIALLY WEST OF THE MISSISSIPPI RIVER. PRECIPITABLE WATER
VALUES ARE NOT THAT IMPRESSIVE...0.5-0.6 INCHES...WHICH MEANS WE
SHOULD NOT SEE MUCH QPF. ONLY CONCERN THAT EXISTS IS THE
PRECIPITATION COULD SHIFT WESTWARD OVER THE NEXT 24-48 HOURS SEEING
MODEL TRENDS. WITH PLENTY OF CLOUDS SPREADING IN SATURDAY MORNING
AND 850MB TEMPS OF 0 TO -2C ON SATURDAY...ANTICIPATING COOL
TEMPERATURES. ONLY 5 TO 10 DEGREES OF COOLING EXPECTED SATURDAY
NIGHT THANKS TO CLOUDS REMAINING IN PLACE.
SUNDAY AND SUNDAY NIGHT...20.00Z GFS/NAM/UKMET/ECMWF/CANADIAN ALL
SHOW ANOTHER SHORTWAVE DROPPING DOWN THE EAST SIDE OF THE WESTERN
U.S. RIDGE. AGAIN...THE MODELS DIFFER WITH THE TRACK...UKMET
FARTHEST WEST NEAR I-35 WITH THE NAM FARTHEST EAST OVER SOUTHWEST
WISCONSIN. IN ANY EVENT...THIS SHORTWAVE COMES THROUGH DURING THE
DAYTIME HOURS. WITH THAT INVERTED SURFACE TROUGH IN PLACE AND
DAYTIME HEATING...SHOULD SEE SOME ISOLATED/SCATTERED SHOWERS
DEVELOP. IF THERE IS ANYTHING GOING AGAINST PRECIPITATION IS A
NORTHEAST TO SOUTHWEST ORIENTED SURFACE RIDGE PROGGED TO BUILD INTO
THE AREA DURING THE AFTERNOON. A DRYING NORTHEAST FLOW COULD LIMIT
SOME OF THE AREAL COVERAGE OF PRECIPITATION...AS SUGGESTED IN 20.00Z
GFS OUTPUT. THEREFORE...FOR NOW CHANCES ARE ONLY 20-30. THE DRYING
FLOW PLUS DAYTIME MIXING SHOULD ALLOW FOR SOME DECREASE IN
CLOUDS...THOUGH A BETTER SHOT OF CLEARING SHOULD COME SUNDAY NIGHT
WITH SUBSIDENCE IN THE WAKE OF THE SHORTWAVE. REGARDING
TEMPERATURES...850MB READINGS ON SUNDAY ARE SIMILAR TO SATURDAY...0
TO -2C. WITH OVERALL LIMITED SUN...ANTICIPATE ANOTHER RELATIVELY
COOL DAY WITH HIGHS IN THE 50S. IF MORE SUN OCCURS THAN
EXPECTED...READINGS MAY GET INTO THE 60S. WITH CLEARING SUNDAY NIGHT
AND THE RIDGE SETTLING IN...COULD SEE YET ANOTHER FROST/FREEZE
NIGHT...ESPECIALLY FOR SOUTHWEST AND CENTRAL WISCONSIN.
.LONG TERM...MONDAY THROUGH THURSDAY NIGHT
333 AM CDT FRI APR 20 2012
DIFFICULT LONG TERM FORECAST...ESPECIALLY GETTING INTO THE MIDDLE OF
NEXT WEEK WHERE MODELS ARE ALL OVER THE PLACE WITH THE HANDLING OF
THE UPPER LEVEL PATTERN OVER THE UPPER MISSISSIPPI RIVER VALLEY
REGION. THROUGH ABOUT TUESDAY...MODELS ARE IN GOOD AGREEMENT
MAINTAINING WESTERN RIDGING AND TROUGHING OVER THE EAST COAST OF THE
U.S.. 500MB HEIGHTS DO RISE MONDAY THROUGH TUESDAY WHICH WILL HELP
TO BRING WARMER AIR INTO THE FORECAST AREA. BY 00Z WEDNESDAY...850MB
TEMPS CLIMB TO 4-8C...IF NOT A LITTLE HIGHER. STILL HAVING TO
MAINTAIN SOME CHANCES OF PRECIPITATION TUESDAY NIGHT...DUE TO A
SHORTWAVE PROGGED TO COME THROUGH THE NORTHWEST FLOW. 20.00Z
ECMWF/GEM ARE PRETTY ACTIVE WITH THIS SHORTWAVE TOO...RESULTING FROM
FAVORABLE DYNAMICAL FORCING. WHAT HAPPENS IN THE WAKE OF THIS
FEATURE IS ANYONES GUESS RIGHT NOW. THE 20.00Z ECMWF IS STUCK WITH
TROUGHING FROM HUDSON BAY DOWN INTO THE EASTERN GREAT LAKES...
MAINTAIN A COOL NORTHWEST FLOW. WOULD PROBABLY END UP WITH
PERIODIC RAIN SHOWERS WITH SHORTWAVES MOVING THROUGH IN THE ECMWF
SCENARIO. ON THE OTHER HAND...THE 20.00Z GFS/GFS ENSEMBLES SAY
WEDNESDAY THROUGH THURSDAY THE WESTERN RIDGE TRIES TO BUILD
TOWARDS THE AREA...BEING PUSHED MORE BY TROUGHING COMING INTO THE
WEST COAST. IF THIS HAPPENS...PERIODIC SHOWER AND THUNDERSTORMS
CHANCES WOULD RESULT AS A WARM FRONT APPROACHES THE REGION. THE
SOLUTIONS ALSO ARE MUCH WARMER THAN THE ECMWF. FOR NOW...HAVE
SPLIT THE DIFFERENCE BETWEEN THE TWO SOLUTIONS. NEEDLESS TO
SAY...CONFIDENCE ON THE PRECIPITATION AND TEMPERATURE FORECASTS IS
LOW.
&&
.AVIATION...THROUGH 18Z SATURDAY
1232 PM CDT FRI APR 20 2012
BIGGEST CONCERN IS ON FOG POTENTIAL TONIGHT AND ITS IMPACT AT THE
TAF SITES. CLOUDS DECREASED AT TAF SITES LATE THIS MORNING...BUT
WITH COLD AIR ALOFT...CUMULUS WAS REFORMING WITH A SCT-BKN DECK.
BASES EXPECTED TO REMAIN IN THE 3K-4K FOOT RANGE THROUGHOUT THE
DAY...BEFORE DIMINISHING THIS EVENING DUE TO LOSS OF HEATING.
TRANSIENT SURFACE RIDGE BUILDS ACROSS THE AREA TONIGHT WITH WINDS
BECOMING LIGHT AND SKIES MAINLY CLEAR...AT LEAST THROUGH 06Z.
POTENTIAL EXISTS FOR SOME FOG FORMATION WITH THE RECENT
RAINS...BUT THERE ARE SOME NEGATIVE FACTORS THAT LOWERS
CONFIDENCE. THOSE NEGATIVE FACTORS ARE AN INCREASE IN HIGH LEVEL
CLOUDS AFTER 06Z...ALONG WITH THE SURFACE RIDGE PUSHING EAST WITH
WINDS BECOMING MORE SOUTHERLY. 20.12Z NAM BUFKIT SOUNDS SHOWING
WINDS STRENGTHENING ABOVE THE BOUNDARY LAYER LATE TONIGHT...WITH
THE 20.15Z RUC NOT QUITE AS AGGRESSIVE WITH THESE WINDS. FEEL
BIGGEST THEREAT FOR FOG WOULD BE AT KLSE...WHERE CLOUDS/WINDS
DELAYED IN GETTING IN THERE. THUS DID INTRODUCE BCFG IN THE TAF.
THIS WILL HAVE TO BE MONITORED CLOSELY DURING THE EVENING.
NEXT SHORTWAVE DROPS THROUGH THE FLOW SATURDAY MORNING...WITH THE
GFS/GEM SHOWING PRECIPITATION ENTERING SOUTHEAST MINNESOTA BETWEEN
15Z-18Z...WHILE NAM HOLDS IT OFF UNTIL AFTER 18Z. DID INTRODUCE
VCSH AT KRST...WITH KLSE REMAINING DRY. CEILINGS EXPECTED TO
REMAIN VFR AT BOTH SITES...ALTHOUGH LOWERING TO AROUND 8K FEET AT KRST.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
333 AM CDT FRI APR 20 2012
WI...FREEZE WARNING FROM 1 AM TO 8 AM CDT SATURDAY FOR
WIZ017-029-034-042>044-053-055.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....AJ
AVIATION...RABERDING