Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/16/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1118 PM MDT SAT APR 13 2013
.UPDATE...
ISSUED AT 1106 PM MDT SAT APR 13 2013
WILL CANCEL HIGH WIND WARNING FOR EL PASO AND TELLER COUNTIES AS
LATEST NAM AND WRF CROSS SECTIONS HAVE BACKED OFF ON THE MOUNTAIN
WAVE SET UP OVERNIGHT. FARTHER SOUTH...WARNING STILL LOOKS GOOD AS
MANY LOCATIONS IN THE SANGRE/WEST ALREADY GUSTING 40-50 MPH AS OF
05Z. BAND OF MODERATE TO HEAVY SNOW HAS DROPPED SOUTH INTO THE
CENTRAL MOUNTAINS LATE THIS EVENING...CURRENT WINTER WEATHER
HIGHLIGHTS ARE ON TRACK.
UPDATE ISSUED AT 907 PM MDT SAT APR 13 2013
LET RED FLAG WARNING EXPIRE AT 2000 MDT...AND MADE SOME VERY MINOR
ADJUSTMENTS TO CURRENT FORECAST. LATEST RUC SUGGESTS HIGH WIND
POTENTIAL IS BETTER OVER THE SANGRES/WETS VERSUS RAMPART
RANGE...THOUGH WILL LEAVE WIND HIGHLIGHTS UNCHANGED FOR NOW AS WE
JUST HAD A 69 MPH GUST REPORTED NEAR ROSITA IN THE WET
MOUNTAINS. WINTER WX HIGHLIGHTS FOR THE CENTRAL MOUNTAINS LOOK GOOD
AS BAND OF HEAVY SNOW IS JUST ABOUT TO REACH THE CONTINENTAL
DIVIDE SOUTH OF I-70.
&&
.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 300 PM MDT SAT APR 13 2013
MAIN CONCERNS INCLUDE THE POTENTIAL FOR HIGH WINDS ALONG AND NR THE
EASTERN MTS TONIGHT...AND SNOW AMOUNTS FOR MAINLY THE CENTRAL MTS.
HAVE BEEN MEETING RED FLAG CRITERIA IN MOST OF THE WARNING AREA THIS
AFTERNOON...ALTHOUGH PUEBLO HAS NOT YET MET THE CRITERIA BECAUSE THE
WINDS HAVE NOT KICKED UP YET. WILL LEAVE THE RED FLAG WARNING AS
IS.
MODEL SHOW UPR LOW OVR NWRN MT MOVING SOUTHEAST INTO FAR WRN SD BY
12Z SUN AND THEN EASTWARD ACRS SD DURING THE DAY.
AHEAD OF THIS SYSTEM SNOW WILL BE MOVING INTO THE CONTDVD THIS
EVENING AND WILL CONTINUE THRU MIDDAY SUNDAY WITH THE NAM AND THE
GFS CONTINUING TO HIT THE CENTRAL CO MTS QUITE HARD WITH SNOW TONIGHT.
SOME SNOW SHOWERS WILL PROBABLY ALSO MOVE INTO WRN AND NRN PORTIONS
OF FREMONT COUNTY TONIGHT AND INTO THE TELLER COUNTY AND PIKES PEAK
AREA...BUT LITTLE ACCUMULATIONS IS EXPECTED. THE OTHER MAIN CONCERN
IS THE 100+ KT JET MOVING OVERHEAD. LOOKING AT CROSS-SECTIONS OFF
THE LOCAL WRF...IT SHOWS 55 TO 65 KT WINDS COMING DOWN THE SIDE OF
PIKES PEAK AND THE RAMPART RANGE INTO FAR WRN EL PASO
COUNTY...MAINLY WEST OF I-25 BEGINNING AROUND 02Z AND THEN SEVERE
GUSTS PROBABLY ENDING AROUND 08Z-09Z. WL BEGIN HIGH WIND WARNING AT
02Z FOR THAT AREA AND RUN IT THROUGH 12Z. FARTHER SOUTH...OVR THE
SANGRES...WETS AND SRN I-25 CORRIDOR THE WRF SHOWS THE HIGH WIND
POTENTIAL CONTINUING A LITTLE LONGER SO WL LEAVE THAT AREA IN A
WARNING THRU 15Z.
AS THAT UPR LOW MOVES E ON SUN...THE MSTR ALONG THE CONTDVD
DECREASES AS DO THE SNOW CHANCES...AND THUS THERE COULD BE JUST SOME
LIGHT ADDITIONAL ACCUMULATIONS IN THE MORNING HOURS...BUT LITTLE IF
ANY IN THE AFTERNOON AS THE NAM ENDS ALL PCPN CHANCES. A COLD FRONT
WL DROP SOUTH INTO THE SERN PLAINS SUN AFTERNOON AND TEMPS WL BE A
LITTLE COOLER THAN TODAY. ON SUNDAY IT WL BE A BIT BREEZY FROM THE
I-25 CORRIDOR AND WESTWARD...AND WINDY OVR THE MOUNTAIN AREAS.
HOWEVER RH VALUES LOOK TOO HIGH TO HAVE FIRE WEATHER CONCERNS.
.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 PM MDT SAT APR 13 2013
...WINTER IS COMING BACK...
MODELS IN OVERALL AGREEMENT WITH THE FORECAST THROUGH THE EXTENDED
WITH ANOTHER LATE SEASON WINTER STORM THROUGH THE MIDDLE OF THE
WORK WEEK.
AN UPPER LEVEL STORM SYSTEM IS FORECAST TO STRENGTHEN AND DROP
SOUTH OVER THE GREAT BASIN SUNDAY NIGHT THROUGH TUESDAY NIGHT
BEFORE SHIFTING EAST ACROSS THE REGION ON WEDNESDAY. MOST OF
SUNDAY NIGHT WILL BE QUIET ACROSS THE REGION WITH INCREASING
CHANCES FOR SNOWFALL ALONG THE CONTINENTAL DIVIDE BY MONDAY
MORNING. AS THE TROUGH DIGS OUT WEST...FLOW WILL BECOMING
INCREASINGLY SOUTHWESTERLY. A DISTURBANCE IN THE FLOW WILL EJECT
ACROSS CENTRAL COLORADO ON MONDAY WITH A PERIOD OF MODERATE TO
HEAVY SNOWFALL FOR THE CENTRAL MOUNTAINS INTO NORTHEAST COLORADO.
THE LATEST MODEL SOLUTIONS KEEP ALMOST ALL THE PLAINS DRY WITH THE
EXCEPTION BEING THE PALMER DIVIDE WHERE SHOWERS ARE POSSIBLE.
SEVERAL INCHES OF SNOWFALL ARE LIKELY ALONG THE CONTINENTAL DIVIDE
THROUGH MONDAY AFTERNOON...WITH THE HIGHEST AMOUNTS EXPECTED OVER
THE CENTRAL MOUNTAINS. GIVEN THE SOUTHWESTERLY FLOW AND MIXING
ACROSS THE REGION...FIRE WEATHER REMAINS A CONCERN. MODELS HINTING
AT THE RATON MESA REGION AND SAN LUIS VALLEY WILL SEE GUSTY WINDS
HOWEVER HUMIDITY VALUES MAY BE A BIT TOO HIGH. CONDITIONS WILL
NEED TO BE MONITORED. AFTERNOON TEMPERATURES HAVE COME IN A BIT
WARMER WITH 6OS TO LOW 70S FORECAST FOR THE PLAINS.
A COLD FRONT WILL SHIFT SOUTH ACROSS THE PLAINS BY MONDAY EVENING
WITH EASTERLY UPSLOPE FLOW AND MOISTURE FILLING IN BEHIND THE
FRONT. MODEL SOLUTIONS AND SOUNDING DATA INDICATES LOW STRATUS
ALONG WITH FOG AND DRIZZLE WILL LIKELY DEVELOP. THERE COULD BE
SOME LIGHT RAIN AS WELL THROUGH THE OVERNIGHT PERIOD. THIS WILL
LIKELY HELP KEEP TEMPERATURES AT OR ABOVE FREEZING FOR THE PLAINS
MONDAY NIGHT INTO TUESDAY MORNING. SNOW WILL CONTINUE ALONG THE
CONTINENTAL DIVIDE.
THE UPPER LEVEL TROUGH WILL SHIFT EAST INTO THE FOUR CORNERS
REGION TUESDAY AFTERNOON. MODELS INDICATING LOWER LEVEL MIXING
WILL SHIFT THE COOLER UPSLOPE ARE BACK EAST ACROSS THE SOUTHWEST
PORTION OF THE PLAINS. NEAR CRITICAL FIRE WEATHER CONDITIONS MAY
ONCE AGAIN BE POSSIBLE OVER THE SAN LUIS VALLEY AND NEAR THE NEW
MEXICO BORDER BY TUESDAY AFTERNOON. WINDS WILL BE THERE...BUT
CONDITIONS WILL REMAIN DEPENDENT ON HUMIDITY VALUES. SNOW WILL
REMAIN PERSISTENT OVER THE CONTINENTAL DIVIDE THROUGH TUESDAY. THE
NORTHEAST HALF OF THE PLAINS WILL BE TRICKY AS FAR AS CLOUD COVER
AND TEMPERATURE FORECAST. IT ALL DEPENDS ON HOW FAR NORTHEAST THE
MIXING CAN OCCUR. AREAS UNDER CLOUDS SHOULD REMAIN COOL.
BY WEDNESDAY THE UPPER SYSTEM TRACKS OVERHEAD AND EAST INTO THE
CENTRAL CONUS BY THURSDAY MORNING. A MUCH STRONGER COLD FRONT WILL
MOVE SOUTH ACROSS THE AREA WEDNESDAY WITH WIDESPREAD SHOWER ACTIVITY
LIKELY ACROSS ALL OF SOUTHERN COLORADO. CURRENT PROGS INDICATE
AREAS OVER THE PALMER DIVIDE...EASTERN MOUNTAINS AND RATON WILL
LIKELY BE FAVORED. TEMPERATURES ARE FORECAST TO DROP QUICKLY
BEHIND THE FRONT WITH 700 MB TEMPERATURES REACHING -13C BY
WEDNESDAY AFTERNOON. THIS WILL LIKELY TURN ALL PRECIPITATION TO
SNOW BY WEDNESDAY EVENING. ALL ACCUMULATIONS ARE EXPECTED TO
REMAIN OVER THE HIGHER ELEVATIONS. TEMPERATURES WEDNESDAY NIGHT
INTO THURSDAY MORNING WILL BE VERY COLD. CURRENT MODEL GUIDANCE IS
INDICATING LOWER 20S FOR THE PLAINS...AND IT MAY BE A FEW DEGREES
COOLER THAN THIS. PRECAUTIONS SHOULD BE TAKEN TO PROTECT SENSITIVE
PLANTS AND SPRINKLER SYSTEMS.
AS THE UPPER SYSTEM TRACK EAST...NORTHWESTERLY FLOW WILL DEVELOP
AND REMAIN IN PLACE THROUGH SATURDAY. THIS WILL LEAD TO DRY
CONDITIONS FOR MOST AREAS...WITH ISOLATED SNOW SHOWER ACTIVITY
POSSIBLE OVER THE CENTRAL MOUNTAINS. ANY DISTURBANCES IN THE FLOW
WILL LIKELY CAUSE UPTICKS IN AREAL COVERAGE AND INTENSITY AND WILL
NEED TO BE WATCHED. TEMPERATURES WILL SLOWLY MODERATE BACK INTO
THE 50S TO LOWER 60S FOR FRIDAY AND SATURDAY. TEMPERATURES ON
THURSDAY NIGHT WILL ONCE AGAIN BE COLD WITH WIDESPREAD FREEZING
TEMPERATURES. MOZLEY
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1106 PM MDT SAT APR 13 2013
EXPECT VFR CONDTIONS AT ALL TAF SITES TONIGHT AND SUNDAY. WEST
WINDS WILL CONTINUE TO BE OCCASIONALLY GUSTY AT ALL 3 SITES
THROUGH THE NIGHT...A FEW GUSTS TO 25-35 KNOTS WILL BE LIKELY.
WINDS GRADUALLY BECOME MORE NORTHWESTERLY AFTER 09Z...THEN WILL
BRIEFLY DIMINISH AROUND 12Z...BEFORE INCREASING AGAIN INTO THE 15
TO 25 KNOT RANGE ON SUNDAY. A FEW SHOWERS MAY REACH THE PALMER
DIVIDE NORTH OF KCOS IN THE 09Z-12Z PERIOD...THOUGH EXPECT MOST
PRECIP TO STAY NORTH OF THE TERMINAL. OVER THE MOUNTAINS...EXPECT
IFR CONDITIONS DUE TO SNOW TO CONTINUE THROUGH MIDDAY OVER THE
CENTRAL MOUNTAINS FROM MONARCH PASS NORTHWARD.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
HIGH WIND WARNING UNTIL 9 AM MDT SUNDAY FOR COZ072>075-078>080-
087-088.
WINTER WEATHER ADVISORY UNTIL NOON MDT SUNDAY FOR COZ059.
WINTER STORM WARNING UNTIL NOON MDT SUNDAY FOR COZ058-060.
&&
$$
UPDATE...ROSE
SHORT TERM...28
LONG TERM...MOZLEY
AVIATION...PETERSEN
AREA FORECAST DISCUSSION
NWS TAMPA BAY RUSKIN FL
811 PM EDT MON APR 15 2013
.UPDATE (TONIGHT THROUGH TUESDAY)...
00Z WATER VAPOR AND H4 RAP ANALYSIS SHOW THE SHORTWAVE DISTURBANCE
FROM SUNDAY CONTINUES TO PULL INTO THE WESTERN ATLANTIC WITH HEIGHTS
REBOUNDING OVER THE SE CONUS/FL PENINSULA. UPPER LEVEL RIDGING WILL
CONTINUE TO BUILD OVER THE NEXT 24 HOURS SETTING UP A VERY
WARM...DARE WE SAY "HOT" TUESDAY FOR MID APRIL.
AT THE SURFACE...WEAK GRADIENT IS IN PLACE THIS EVENING...WITH FLOW
CURRENTLY DOMINATED BY LOCAL SEA-BREEZE CIRCULATIONS AND
THUNDERSTORM OUTFLOW (OVER THE SOUTHERN HALF OF THE PENINSULA). WITH
THE SETTING OF THE SUN AND LOSS OF LOW LEVEL SEA-BREEZE
FOCUS...WOULD EXPECT THE GRADIENT TO TIGHTEN SLIGHTLY DURING THE
OVERNIGHT AND RETURN US TO AN EASTERLY SYNOPTIC FLOW.
REGIONAL RADAR STILL SHOW A SCATTERING OF LINGERING CONVECTION THIS
EVENING TO THE SOUTH OF HILLSBOROUGH AND POLK COUNTIES. COLUMN
MOISTURE WAS GENERALLY INSUFFICIENT TO SUPPORT THE DEEP CONVECTION
FURTHER NORTH...AND SEEING A DRY EVENING PERIOD FOR THE I-4 CORRIDOR
AND NORTHWARD. AS MENTIONED ABOVE...STORMS OVER THE INTERIOR SOUTH
MAY LINGER FOR ANOTHER HOUR OR 2...BUT WILL GENERALLY BE ON THE
DECLINE WITH THE LOSS OF DIURNAL HEATING. AFTER THESE STORMS ARE
GONE BY 2-3Z...EXPECTING A DRY AND WARM OVERNIGHT PERIOD
REGION-WIDE. LOW TEMPS BY SUNRISE WILL BE IN THE LOWER/MID 60S NORTH
OF I-4 AND THE MID/UPPER 60S FURTHER SOUTH.
TEMPERATURES WILL RISE QUICKLY ON TUESDAY UNDER THE DEEP LAYER
SUPPRESSION OF THE UPPER RIDGE. LOCATIONS AWAY FROM THE BEACHES WILL
RISE WELL INTO THE 80S AND EXPECT MANY LOCATIONS TO TOP OUT IN THE
LOWER 90S...ESPECIALLY FROM I-4 SOUTH. COLUMN MOISTURE WILL CONTINUE
TO DRY OUT...HOWEVER...MAY STILL SEE JUST ENOUGH AFTERNOON FOCUS
ALONG DEVELOPING SEA-BREEZES TO POP AN ISOLATED STORM OR 2...MAINLY
DOWN TOWARD THE FORT MYERS AREA. HAVE ADDED A SLIGHT 20% POP IN
AFTER 2PM FOR THESE FAR SOUTHERN ZONES. ELSEWHERE...ANY SHOWERS THAT
POP WILL BE REMOTE ENOUGH TO KEEP MENTION OUT OF THE CURRENT
FORECAST.
&&
.AVIATION...
A FEW THUNDERSTORMS PERSIST JUST EAST OF THE FMY/RSW TERMINALS AND
OVER THE SOUTHERN INTERIOR. THE STORMS WILL DISSIPATE SHORTLY AFTER
SUNSET. SKIES WILL BECOME MOSTLY CLEAR OVERNIGHT WITH LCL MVFR CIGS
AND VSBYS DUE TO FOG DEVELOPING LATE TONIGHT OVER THE INTERIOR AND
MAY AFFECT LAL. VFR CONDITIONS WILL PREVAIL TUESDAY WITH SCT CU
040-050 AND A FEW AFTERNOON SHOWERS/THUNDERSTORMS WITH LCL MVFR
CIGS/VSBYS.
&&
.MARINE...
BUILDING HIGH PRESSURE SHOULD ALLOW FOR LIGHT WINDS AND WAVES. RAIN
CHANCES SHOULD GENERALLY DIMINISH THROUGH THE FORECAST PERIOD UNTIL
THE NEXT FRONTAL SYSTEM ARRIVES LATER IN THE WEEK. ONLY EXCEPTION
MAY BE A FEW ISOLATED STORMS PUSHING WEST OFF THE COAST DOWN TOWARD
CHARLOTTE/LEE COUNTIES DURING THE LATE AFTERNOON/EARLY EVENING HOURS
OF TUESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 70 88 69 86 / 10 10 10 0
FMY 71 90 68 89 / 10 20 20 0
GIF 69 90 67 87 / 10 10 0 0
SRQ 68 87 68 86 / 10 10 10 0
BKV 63 90 64 87 / 10 10 10 0
SPG 73 88 72 86 / 10 10 10 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GULF WATERS...NONE.
&&
$$
UPDATE...MROCZKA
AVIATION...OGLESBY
AREA FORECAST DISCUSSION
NWS CHARLESTON SC
152 PM EDT SUN APR 14 2013
.SYNOPSIS...
THIS AFTERNOON...THE REGION WILL REMAIN UNDER A WEDGE OF HIGH
PRESSURE AS A DEVELOPING LOW PRESSURE SYSTEM MOVES OUT OF THE GULF
OF MEXICO. THE LOW WILL PASS OVER OR JUST SOUTH OF THE REGION
AND OFF THE SOUTHEAST COASTLINE TONIGHT INTO EARLY MONDAY. HIGH
PRESSURE WILL GRADUALLY STRENGTHEN OVER THE WESTERN ATLANTIC
TUESDAY THROUGH FRIDAY BEFORE A COLD FRONT MOVES IN FRIDAY NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EARLY SUNDAY AFTERNOON...OVERRUNNING PRECIPITATION CONTINUED TO
OVERSPREAD SOUTHERN/WESTERN COUNTIES OF THE FORECAST AREA.
PER AREA RADAR TRENDS AND 11Z HRRR HIGH RESOLUTION GUIDANCE WHICH
APPEARS TO HAVE A REASONABLE HANDLE ON PRECIPITATION EVOLUTION...
CONTINUED TO RAISE POPS AND ACCELERATE THE N/E PROGRESS OF
SHOWERS. MAX AFTERNOON POPS ARE NOW GRADUATED FROM CATEGORICAL
S/W TO CHANCE N/E. QPF SHOULD REMAIN LIMITED THROUGH LATE
AFTERNOON...WITH 0.25 TO 0.50 INCH WHERE LONGEST DURATION
PRECIPITATION OCCURS ACROSS S/E...WITH ELEVATED CONVECTION/LOCALLY
HEAVIER RAINFALL RATES ARRIVING THIS EVENING.
ISOLATED/ELEVATED THUNDERSTORMS COULD PUSH INTO LOCATIONS NEAR THE
ALTAMAHA RIVER/ADJACENT COASTAL WATERS BY LATE AFTERNOON...BUT THE
POTENTIAL FOR ANY SEVERE WEATHER WILL REMAIN VERY LOW THROUGH LATE
AFTERNOON.
AFTERNOON TEMPERATURES WILL REMAIN IN THE 60S WHERE SHOWERS HAVE
ALREADY ARRIVED WITHIN THE WEDGE REGIME ACROSS S/W COUNTIES...AND
TEMPERATURES IN THE LOWER TO MID 70S FARTHER N/E WILL FALL BACK
INTO THE 60S AS SHOWERS ARRIVE...LATEST ACROSS THE CHS TRI-COUNTY
REGION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
TONIGHT...A COMPLEX AND INTERESTING PERIOD INDEED AS IMPRESSIVE
DYNAMICS ROLL THROUGH WITH HINTS OF SOME UPPER JET COUPLING.
SURFACE LOW PRES WAVES WILL RIPPLE ALONG A LIFTING WARM FRONT
OVERNIGHT WITH INCREASING LOW LEVEL CONVERGENCE AND MAINLY
ELEVATED INSTABILITY LIFTING NORTHWARD WITH TIME. MODELS HAVE
THEIR USUAL TIMING AND PLACEMENT DIFFERENCES WITH THE FEATURES BUT
A FEW THINGS CAUGHT OUR EYE FROM THE GFS/ECMWF. BOTH MODELS PROG
AT LEAST 50-60 KT OF BULK SHEAR THROUGH OUR SOUTHERN ZONES AND WE
ARE GOING TO NEED TO KEEP CLOSE TABS ON THE PROGRESSION OF THE
WARM FRONT AFTER MIDNIGHT. WE THINK AN INITIAL SHOT OF ELEVATED
CONVECTIVE RAINS WILL LOCK IN PLENTY OF LOW LEVEL STABILITY ACROSS
THE FORECAST AREA...BUT THERE COULD BE A SMALL CHANCE FOR
WORRISOME INSTABILITY ALONG SE GEORGIA CLOSE TO THE ALTAMAHA RIVER
AND POSSIBLY AN OVERNIGHT WARM FRONT GATE FEATURE NEARING THE
COASTAL PARTS OF SE SOUTH CAROLINA...MORE LIKELY TO REMAIN OFFSHORE.
WITH THE AMOUNT OF FORCING AND INSTABILITY GRADIENTS PROGGED...
ISOLATED SEVERE WEATHER FROM ELEVATED HAIL AND A SMALL POTENTIAL
RISK OF A TORNADO ALONG AND S OF THE WARM FRONT CANNOT BE RULED
OUT. AT THIS TIME IT APPEARS THE GREATER RISK WILL BE ALONG AND
S OF THE ALTAMAHA RIVER ENTRANCE REGION. CHANCES AT THIS TIME NOT
ENOUGH TO WARRANT MENTIONS IN OUR HAZARDOUS WEATHER OUTLOOK.
ANOTHER POTENTIAL ISSUE WILL BE LOCALLY HEAVY CONVECTIVE RAINFALL...
ESPECIALLY FALLING AROUND TIMES OF A NEAR MIDNIGHT HIGH TIDE IN
COASTAL AREAS. OVERALL...THE PROGRESSIVE NATURE OF THIS SYSTEM IS
SUCH THAT QPF AMOUNTS HELD DOWN BUT NOT RULING OUT SOME LOCALIZED
HEAVY RAINS. OTHERWISE...PLENTY OF SHOWERS AND TSTMS SWEEPING
THOUGH GEORGIA INTO SOUTH CAROLINA TONIGHT WITH MILD TEMPS HANGING
UP IN THE LOWER 60S.
A BROAD 500 MB RIDGE WILL BUILD IN MONDAY THROUGH WEDNESDAY. ON
MONDAY A WEAK SURFACE WEDGE OF HIGH PRESSURE WILL REMAIN ACROSS
SOUTHERN SC ALONG WITH CONSIDERABLE MOISTURE BELOW 800 MB. WEAK
FORCING ON THE WESTERN PERIPHERY OF THE DEPARTING LOW MAY ALLOW FOR
SCATTERED SHOWERS MAINLY THROUGH EARLY AFTERNOON. EXTENSIVE CLOUD
COVER AND WEAK COLD ADVECTION WILL LIMIT HIGH TEMPS TO THE MID TO
UPPER 70S.
AS UPPER HEIGHTS RISE ON TUESDAY...THE SURFACE HIGH WILL SHIFT OFF
THE COAST. SOME LOW-LEVEL DRYING WILL SCOUR OUT SOME OF THE CLOUD
COVER BUT AN ONSHORE FLOW WILL MAINTAIN ENOUGH BOUNDARY LAYER
MOISTURE TO SUPPORT OVERNIGHT STRATOCU AND CUMULUS DEVELOPMENT
DURING DAYTIME HOURS. KNOCKING A COUPLE DEGREES OF THICKNESS PROGS
TO ACCOUNT FOR THE CLOUDS GIVES US HIGHS IN THE LOWER 80S EXCEPT MID
70S AT THE COAST DUE TO THE ONSHORE FLOW AND SEABREEZE.
TEMPS WILL BE ANOTHER 1-3 DEGREES WARMER ON WEDNESDAY UNDER PARTLY
TO MOSTLY SUNNY SKIES. WE KEPT A SLIGHT CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS FAR INLAND GA WHERE SOME LOW-LEVEL INSTABILITY
AND -4 TO -5C LIFTED INDICES MAY SUPPORT SOME CONVECTION ONCE THE
SEABREEZE PUSHES INLAND.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
THE UPPER RIDGE WILL HANG ON FOR ONE MORE DAY BEFORE A LARGE SCALE
PATTERN SHIFT OCCURS. A PRONOUNCED LONGWAVE TROUGH WILL SPREAD
ACROSS PRETTY MUCH THE ENTIRE CONTIGUOUS UNITED STATES FRIDAY
THROUGH SUNDAY. A STRONG COLD FRONT WILL SWEEP THROUGH THE AREA
FRIDAY NIGHT WITH DRY CANADIAN HIGH PRESSURE BUILDING IN ITS WAKE.
WE EXPECT DECENT COVERAGE OF SHOWERS AND THUNDERSTORMS FRIDAY
AFTERNOON THROUGH FRIDAY NIGHT...THEN DRIER AND MUCH COOLER WEATHER
FOR THE WEEKEND. HIGHS ON SATURDAY COULD STRUGGLE TO REACH 70
DEGREES AND SATURDAY NIGHT WE COULD SEE SOME UPPER 40S IN SPOTS.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR INTO THIS EVENING...EVEN FOR A TIME AFTER SHOWERS ARRIVE
INITIALLY AT KSAV AND BY EARLY EVENING AT KCHS DUE TO RELATIVELY
DRY LOW LEVEL AIRMASS IN PLACE. HOWEVER...FLIGHT CONDITIONS WILL
DETERIORATE TONIGHT...PERHAPS GRADUALLY THROUGH MVFR TO IFR OR
RAPIDLY TO IFR/LIFR AS LOW CLOUDS/FOG DEVELOP IN PLACE.
MEANWHILE...ELEVATED THUNDERSTORMS COULD OCCUR AT EITHER TERMINAL
TONIGHT...BUT THE ODDS ARE SOMEWHAT GREATER AT KSAV THUS INCLUDED
A PERIOD OF VCTS THERE. AFTER PRECIPITATION ENDS...LOW LEVEL
MOISTURE/FLIGHT RESTRICTIONS WILL LINGER AT LEAST THROUGH MONDAY
MORNING...THUS INDICATED ONLY MODEST IMPROVEMENT TO MVFR CEILINGS
AS THE BOUNDARY LAYER WARMS/DEEPENS BEGINNING AROUND 15Z MONDAY.
EXTENDED AVIATION OUTLOOK...MVFR/IFR CONDITIONS LIKELY LATE SUNDAY
NIGHT INTO MONDAY MORNING...OTHERWISE MVFR CEILINGS AND SOME
SHALLOW GROUND FOG POSSIBLE DURING THE OVERNIGHT HOURS MONDAY
THROUGH THURSDAY.
&&
.MARINE...
A TIGHTENING SURFACE PRESSURE GRADIENT BETWEEN A RIDGE OF HIGH
PRESSURE CENTERED N/W OF THE WATERS AND A SURFACE WAVE OF LOW
PRESSURE EJECTING ENE FROM THE GULF OF MEXICO WILL MAINTAIN
ONSHORE FLOW THIS AFTERNOON...WITH WINDS INCREASING/SEAS BUILDING
TONIGHT. CAPPED WINDS AT 20 KT AND SEAS AT 4-5 FT THIS
AFTERNOON... BUT FORECAST UNCERTAINTY REMAINS HIGH AS GRADIENTS
COULD BECOME TIGHTER THAN EXPECTED SUPPORTING HIGHER WINDS/LARGER
SEAS THAN CURRENTLY EXPECTED LATER TODAY OR TONIGHT.
WE INDICATE SEAS BUILDING TO 4 TO 6 FT BRIEFLY TONIGHT OVER OUTER
GEORGIA WATERS BEYOND 20 NM BUT WERE HESITANT TO ISSUE THE SMALL
CRAFT ADVISORY JUST YET GIVEN UNCERTAINTIES WITH THE PROGRESSION
OF THE WARM FRONT. WE CANNOT RULE OUT MARGINAL SCA CONDITIONS
ALONG PARTS OF THE UPPER SOUTH CAROLINA COAST THIS EVENING IF
THE GRADIENT PINCHES AND EVEN AT FORT PULASKI THIS AFTERNOON
WITH OCCASIONAL WIND GUSTS EXCEED 20 KT. ALSO OF CONCERN...
THUNDERSTORMS...A FEW STRONG...COULD IMPACT THE COASTAL WATERS
TONIGHT.
A MODERATE ONSHORE FLOW WILL PREVAIL MONDAY THROUGH THURSDAY AS HIGH
PRESSURE GRADUALLY BUILDS OVER THE WESTERN ATLANTIC. DECENT
SEA-BREEZES EXPECTED EACH AFTERNOON ALONG THE COAST AS INLAND AREAS
WARM UP. WINDS WILL BECOME SOUTHERLY THURSDAY NIGHT AND FRIDAY AHEAD
OF A COLD FRONT. SMALL CRAFT ADVISORY WINDS/SEAS MAY DEVELOP AHEAD
OF THE FRONT...THEN PERSIST IN ITS WAKE ON SATURDAY AS WINDS SHIFT
TO NNE.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...SPR
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...SPR
MARINE...JRL/SPR
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1227 PM CDT SUN APR 14 2013
.DISCUSSION...
ISSUED 1015 AM CDT SUN APR 14 2013
REMAINDER OF SHOWERS/SPRINKLES HAVE PUSHED INTO INDIANA. WHILE
REGIONAL RADAR MOSAICS SHOW SOME SHOWERS OVER CENTRAL ILLINOIS...
THIS IS DUE TO THE MORE DISTANT RADAR BEAMS REACHING THE
ALTOCUMULUS LAYER...AS THE LINCOLN RADAR IS PRETTY CLEAR DIRECTLY
OVER CENTRAL ILLINOIS. CU-RULE IS LARGELY ABOVE ZERO THIS
AFTERNOON INDICATING LOW CHANCES OF CUMULUS...ALTHOUGH A TONGUE OF
IT IS PROGGED TO MOVE NORTHEAST FROM THE ST LOUIS AREA LATE IN THE
AFTERNOON...AND THUS ANY ADDITIONAL PRECIP SHOULD BE SPRINKLES AT
BEST.
MAIN CONCERN REMAINS WITH THE WINDS TODAY. VAD WINDS OFF THE
LINCOLN AND ST LOUIS RADARS SHOWING 40 KNOTS ON THE LOWEST GATE AT
10 AM. WITH THE ALTOCUMULUS TRYING TO LIFT OUT...SHOULD START
SEEING SOME INCREASED MIXING TO BRING THIS DOWN TO THE SURFACE...
HOWEVER THERE IS A DECENT CIRRUS SHIELD OVER ABOUT THE SOUTHEAST
HALF OF THE CWA IN ASSOCIATION WITH CONVECTION ACROSS THE SOUTHEAST
U.S. LATEST RAP AND HRRR SHOWING THE 3 TO 6 PM TIME FRAME AS MOST
LIKELY TO SEE THE HIGHEST WIND GUSTS OF 40-45 MPH. NO HEADLINE
CHANGES PLANNED AS THE SOUTHEAST CWA STILL IS RATHER BORDERLINE
WITH THE WINDS. TEMPERATURES LOOKING GOOD SO FAR AND NO CHANGES
WERE MADE...ALTHOUGH THERE WERE SOME DOWNWARD ADJUSTMENTS IN THE
DEW POINT GRIDS.
GEELHART
&&
.AVIATION...
ISSUED 1225 PM CDT SUN APR 14 2013
INITIAL CONCERNS ARE WITH WINDS...WHICH HAVE BEEN INCREASING WEST
OF KBMI-KSPI IN THE CLEAR SLOT. HIGHEST GUSTS LIKELY IN THE
21-00Z TIME FRAME IN THESE AREAS. AREA FURTHER EAST WILL SEE HIGH
CLOUDS WHICH MAY TEMPER THE MIXING SOME...BUT SHOULD STILL SEE
SOUTHERLY WINDS GUSTING TO AROUND 30 KNOTS. DURING THE EVENING...A
COLD FRONT WILL APPROACH FROM THE WEST...LOWERING CEILINGS TO
AROUND 5000 FEET BY THE TIME ASSOCIATED SHOWER AND THUNDERSTORM
ACTIVITY ARRIVES...LIKELY TOWARD 06Z AT KPIA AND SLOWLY MOVING TO
THE OTHER TAF SITES. GUIDANCE SUGGESTING SOME TEMPO PERIODS OF
MVFR CEILINGS/VISIBILITIES AS THE FRONT PASSES...THEN IMPROVEMENT
AFTER ABOUT 09-10Z.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 300 AM CDT SUN APR 14 2013
FORECAST CONCERN TODAY IS HOW STRONG SOUTHERLY WINDS GET AND IF
WIND ADVISORY NEEDED. MODELS AGREE WITH BIG WARM UP TODAY INTO THE
LOW TO MID 70S WITH MOSTLY SUNNY SKIES DEVELOPING FROM SOUTH TO NORTH.
00Z MODEL SUITE CONTINUES TO ADVERTISE A VERY UNSETTLED WEATHER
PATTERN THIS WORK WEEK WITH BEST CHANCES OF SHOWERS AND
THUNDERSTORMS WITH HEAVIEST RAINS OCCURRING WED AFTERNOON INTO THU.
SHORT TERM...TODAY THROUGH THURSDAY
RADAR MOSAIC AND SURFACE OBS SHOW A BAND OF WAA SHOWERS AND EVEN A
FEW ISOLATED THUNDERSTORMS AT TIMES OVER CENTRAL IL AND LIFTING
NE OF A SPRINGFIELD TO EFFINGHAM LINE AND AS FAR NE AS I-74. THIS
BAND OF CONVECTION TO CONTINUE LIFTING NE THIS MORNING AND BE NE
OF CENTRAL IL BY MID MORNING. EARLY MORNING SURFACE MAP SHOWS
STRONG 988 MB LOW PRESSURE STILL DEEPENING OVER SE CO INTO NW KS
WHILE ITS WARM FRONT EXTENDED EASTWARD OVER NORTHERN KS INTO
CENTRAL MO. WEAK 1019 MB HIGH PRESSURE WAS OVER SE OHIO AND
DRIFTING EAST AWAY FROM IL. TEMPS WERE IN THE 40S OVER CENTRAL/SE
IL EARLY THIS MORNING...RANGING FROM LOWER 40S AT DANVILLE AND
PARIS TO THE UPPER 40S FROM MACOMB TO SPRINGFIELD TO EFFINGHAM AND
OLNEY SW. ESE WINDS WERE 5-15 MPH. ALOFT A STRONG 532 DM 500 MB
LOW WAS NE OF LAKE SUPERIOR WHILE A 535 DM 500 MB LOW WAS OVER
WESTERN MT. UPPER LEVEL RIDGING WAS OVER FL AND OFF THE CA COAST.
STRONG LOW PRESSURE OVER SE CO/NW KS TO WEAKEN TO 996 MB AT IT
EJECTS NE TO THE SD/MN BORDER BY THIS EVENING. THIS TO BRING ANOTHER
MAJOR WINTER STORM TO PARTS OF MT/ND AND MN...WHILE IL STAYS ON
THE WARM SIDE OF THIS STRONG STORM SYSTEM WITH INCREASING PRESSURE
GRADIENT TODAY LEADING TO SOUTHERLY WINDS APPROACHING WIND
ADVISORY CRITERIA (SUSTAINED 30 MPH FOR AN HOUR OR MORE AND OR
WIND GUSTS OF 45 MPH OR HIGHER) THIS AFTERNOON NW OF I-70 AND
FROM I-57 WEST. WILL ISSUE A WIND ADVISORY THIS AFTERNOON FOR
CENTRAL IL NORTH OF I-70 FROM NOON TO 7 PM...THOUGH EDGAR AND
VERMILION COUNTIES AROUND DANVILLE AND PARIS MAY STRUGGLE TO REACH
THE WIND ADVISORY CRITERIA THIS AFTERNOON. HIGHS IN THE LOW TO MID
70S THIS AFTERNOON WHICH IS ABOUT 10 DEGREES ABOVE NORMAL FOR MID
APRIL.
STRONG SURFACE AND CUTOFF LOW TO LIFT NE ACROSS MN TONIGHT WHILE
BRINGING A COLD FRONT SE ACROSS THE IL RIVER VALLEY OVERNIGHT...
RE TURING A CHANCE OF SHOWERS AND THUNDERSTORMS TO CENTRAL IL
ESPECIALLY NW AREAS AND INCREASE POPS IN THIS AREA. MODELS
GRADUALLY SHIFT THE COLD FRONT INTO SE IL DURING THE DAY MON AND
CONTINUES CHANCES OF SHOWERS AND THUNDERSTORMS...WHICH GET INTO SE
IL TOO ON MONDAY. SPC KEEPS SLIGHT RISK OF SEVERE STORMS SW OF OUR
SE COUNTIES FOR MON/MON NIGHT BUT WILL NEED TO BE WATCHED FOR
AREAS SE OF I-70 WHICH WILL BE CLOSEST TO THE FRONTAL BOUNDARY
WHICH IS BECOMING QUASI-STATIONARY FOR A TIME INTO TUE AND CONTINUES
CHANCES OF SHOWERS/THUNDERSTORMS ACROSS CENTRAL/SE IL. WILL BE A
FAIRLY STRONG TEMP GRADIENT FROM NW TO SE MON/TUE WITH WARMEST
READINGS IN SE IL WHERE HIGHS 70-75F WHILE MID TO UPPER 50S OVER
THE IL RIVER VALLEY OF NW IL.
BEST CHANCES OF SHOWERS AND THUNDERSTORMS WITH POSSIBLE HEAVY
RAINS TO OCCUR FROM WED AFTERNOON INTO THU...GRADUALLY SHIFTING
INTO EASTERN IL THU. RAINFALL AMOUNTS OF 2-3 INCHES POSSIBLE BY
THU NIGHT ACROSS AREA. STILL SOME TIMING DIFFERENCES WITH STRONG
LOW PRESSURE AND COLD FRONT MOVING THROUGH CENTRAL IL WED NIGHT
AND SE IL THU MORNING.
LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
SHOWERS TO BECOME LIGHTER AND MORE SCATTERED IN NATURE THU NIGHT
AND FRI WITH STRONG STORM SYSTEM EXITING EAST OF IL. THOUGH STRONG
UPPER LEVEL TROF MOVING EAST INTO IL FRIDAY TO KEEP LOW CLOUDS
AROUND ALONG WITH CHANCES OF LIGHT SHOWERS AND BELOW NORMAL
TEMPERATURES. A FEW MODELS ARE SHOWING A SLIPPER SYSTEM BRINGING
SOME QPF INTO IL THIS WEEKEND THOUGH WILL ONLY CARRY SLIGHT CHANCE
POPS AT BEST SAT NIGHT AND SUNDAY. COLDEST TEMPS EXPECTED FRIDAY
AND FRI NIGHT WHEN LOWS COULD REACH AROUND FREEZING. TEMPS MODIFY
INTO THE 50S THIS WEEKEND WHICH IS ABOUT 10 DEGREES COLDER THAN
NORMAL.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ILZ027>031-036>038-
040>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1018 AM CDT SUN APR 14 2013
.DISCUSSION...
ISSUED 1015 AM CDT SUN APR 14 2013
REMAINDER OF SHOWERS/SPRINKLES HAVE PUSHED INTO INDIANA. WHILE
REGIONAL RADAR MOSAICS SHOW SOME SHOWERS OVER CENTRAL ILLINOIS...
THIS IS DUE TO THE MORE DISTANT RADAR BEAMS REACHING THE
ALTOCUMULUS LAYER...AS THE LINCOLN RADAR IS PRETTY CLEAR DIRECTLY
OVER CENTRAL ILLINOIS. CU-RULE IS LARGELY ABOVE ZERO THIS
AFTERNOON INDICATING LOW CHANCES OF CUMULUS...ALTHOUGH A TONGUE OF
IT IS PROGGED TO MOVE NORTHEAST FROM THE ST LOUIS AREA LATE IN THE
AFTERNOON...AND THUS ANY ADDITIONAL PRECIP SHOULD BE SPRINKLES AT
BEST.
MAIN CONCERN REMAINS WITH THE WINDS TODAY. VAD WINDS OFF THE
LINCOLN AND ST LOUIS RADARS SHOWING 40 KNOTS ON THE LOWEST GATE AT
10 AM. WITH THE ALTOCUMULUS TRYING TO LIFT OUT...SHOULD START
SEEING SOME INCREASED MIXING TO BRING THIS DOWN TO THE SURFACE...
HOWEVER THERE IS A DECENT CIRRUS SHIELD OVER ABOUT THE SOUTHEAST
HALF OF THE CWA IN ASSOCIATION WITH CONVECTION ACROSS THE SOUTHEAST
U.S. LATEST RAP AND HRRR SHOWING THE 3 TO 6 PM TIME FRAME AS MOST
LIKELY TO SEE THE HIGHEST WIND GUSTS OF 40-45 MPH. NO HEADLINE
CHANGES PLANNED AS THE SOUTHEAST CWA STILL IS RATHER BORDERLINE
WITH THE WINDS. TEMPERATURES LOOKING GOOD SO FAR AND NO CHANGES
WERE MADE...ALTHOUGH THERE WERE SOME DOWNWARD ADJUSTMENTS IN THE
DEW POINT GRIDS.
GEELHART
&&
.AVIATION...
ISSUED 628 AM CDT SUN APR 14 2013
VFR CONDITIONS SHOULD PREVAIL AT ALL TAF SITES MOST OF THE TAF
PERIOD...EXCEPT FOR WHEN THE FRONTAL SYSTEM MOVES INTO THE AREA
LATE TONIGHT. MID AND HIGH CLOUDS WILL PREVAIL AT ALL SITES AS A
WARM FRONT LIFTS NORTHWARD TODAY...ENDING ANY THREAT FOR PCPN THIS
MORNING. THE AREA WILL SEE A LITTLE CU AROUND 5KFT REST OF THE DAY
AHEAD OF THE NEXT WEATHER SYSTEM. THEN MODELS FORECAST SHOWERS AND
THUNDERSTORMS MOVING INTO THE AREA CLOSE TO MIDNIGHT...REACHING
PIA 04Z AND SPI/BMI BY 06Z. WILL START AS VCTS BUT THEN BRING IN
TEMPO GROUP OF THUNDERSTORMS ON STATION AT 05Z AT PIA AND 07Z AT
SPI/BMI. THE VCTS WILL BEGIN AT DEC AT 08Z AND AT 09Z AT CMI.
MODELS FORECAST PCPN DIMINISHING AS IT MOVES EAST SO WILL NOT ADD
TEMPO GROUP AT THIS TIME DUE TO HIGH DEGREE OF UNCERTAINTY. WINDS
WILL BE WINDY TODAY...BECOMING VERY WINDY AND GUSTY THIS
AFTERNOON. TAFS WILL HAVE GUSTS AS HIGH AS 35-37KTS FOR THIS
AFTERNOON. WINDS WILL DIMINISH SOMEWHAT RIGHT AFTER SUNSET. WIND
DIRECTION WILL BE SOUTHERLY THROUGH THE PERIOD.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 300 AM CDT SUN APR 14 2013
FORECAST CONCERN TODAY IS HOW STRONG SOUTHERLY WINDS GET AND IF
WIND ADVISORY NEEDED. MODELS AGREE WITH BIG WARM UP TODAY INTO THE
LOW TO MID 70S WITH MOSTLY SUNNY SKIES DEVELOPING FROM SOUTH TO NORTH.
00Z MODEL SUITE CONTINUES TO ADVERTISE A VERY UNSETTLED WEATHER
PATTERN THIS WORK WEEK WITH BEST CHANCES OF SHOWERS AND
THUNDERSTORMS WITH HEAVIEST RAINS OCCURRING WED AFTERNOON INTO THU.
SHORT TERM...TODAY THROUGH THURSDAY
RADAR MOSAIC AND SURFACE OBS SHOW A BAND OF WAA SHOWERS AND EVEN A
FEW ISOLATED THUNDERSTORMS AT TIMES OVER CENTRAL IL AND LIFTING
NE OF A SPRINGFIELD TO EFFINGHAM LINE AND AS FAR NE AS I-74. THIS
BAND OF CONVECTION TO CONTINUE LIFTING NE THIS MORNING AND BE NE
OF CENTRAL IL BY MID MORNING. EARLY MORNING SURFACE MAP SHOWS
STRONG 988 MB LOW PRESSURE STILL DEEPENING OVER SE CO INTO NW KS
WHILE ITS WARM FRONT EXTENDED EASTWARD OVER NORTHERN KS INTO
CENTRAL MO. WEAK 1019 MB HIGH PRESSURE WAS OVER SE OHIO AND
DRIFTING EAST AWAY FROM IL. TEMPS WERE IN THE 40S OVER CENTRAL/SE
IL EARLY THIS MORNING...RANGING FROM LOWER 40S AT DANVILLE AND
PARIS TO THE UPPER 40S FROM MACOMB TO SPRINGFIELD TO EFFINGHAM AND
OLNEY SW. ESE WINDS WERE 5-15 MPH. ALOFT A STRONG 532 DM 500 MB
LOW WAS NE OF LAKE SUPERIOR WHILE A 535 DM 500 MB LOW WAS OVER
WESTERN MT. UPPER LEVEL RIDGING WAS OVER FL AND OFF THE CA COAST.
STRONG LOW PRESSURE OVER SE CO/NW KS TO WEAKEN TO 996 MB AT IT
EJECTS NE TO THE SD/MN BORDER BY THIS EVENING. THIS TO BRING ANOTHER
MAJOR WINTER STORM TO PARTS OF MT/ND AND MN...WHILE IL STAYS ON
THE WARM SIDE OF THIS STRONG STORM SYSTEM WITH INCREASING PRESSURE
GRADIENT TODAY LEADING TO SOUTHERLY WINDS APPROACHING WIND
ADVISORY CRITERIA (SUSTAINED 30 MPH FOR AN HOUR OR MORE AND OR
WIND GUSTS OF 45 MPH OR HIGHER) THIS AFTERNOON NW OF I-70 AND
FROM I-57 WEST. WILL ISSUE A WIND ADVISORY THIS AFTERNOON FOR
CENTRAL IL NORTH OF I-70 FROM NOON TO 7 PM...THOUGH EDGAR AND
VERMILION COUNTIES AROUND DANVILLE AND PARIS MAY STRUGGLE TO REACH
THE WIND ADVISORY CRITERIA THIS AFTERNOON. HIGHS IN THE LOW TO MID
70S THIS AFTERNOON WHICH IS ABOUT 10 DEGREES ABOVE NORMAL FOR MID
APRIL.
STRONG SURFACE AND CUTOFF LOW TO LIFT NE ACROSS MN TONIGHT WHILE
BRINGING A COLD FRONT SE ACROSS THE IL RIVER VALLEY OVERNIGHT...
RE TURING A CHANCE OF SHOWERS AND THUNDERSTORMS TO CENTRAL IL
ESPECIALLY NW AREAS AND INCREASE POPS IN THIS AREA. MODELS
GRADUALLY SHIFT THE COLD FRONT INTO SE IL DURING THE DAY MON AND
CONTINUES CHANCES OF SHOWERS AND THUNDERSTORMS...WHICH GET INTO SE
IL TOO ON MONDAY. SPC KEEPS SLIGHT RISK OF SEVERE STORMS SW OF OUR
SE COUNTIES FOR MON/MON NIGHT BUT WILL NEED TO BE WATCHED FOR
AREAS SE OF I-70 WHICH WILL BE CLOSEST TO THE FRONTAL BOUNDARY
WHICH IS BECOMING QUASI-STATIONARY FOR A TIME INTO TUE AND CONTINUES
CHANCES OF SHOWERS/THUNDERSTORMS ACROSS CENTRAL/SE IL. WILL BE A
FAIRLY STRONG TEMP GRADIENT FROM NW TO SE MON/TUE WITH WARMEST
READINGS IN SE IL WHERE HIGHS 70-75F WHILE MID TO UPPER 50S OVER
THE IL RIVER VALLEY OF NW IL.
BEST CHANCES OF SHOWERS AND THUNDERSTORMS WITH POSSIBLE HEAVY
RAINS TO OCCUR FROM WED AFTERNOON INTO THU...GRADUALLY SHIFTING
INTO EASTERN IL THU. RAINFALL AMOUNTS OF 2-3 INCHES POSSIBLE BY
THU NIGHT ACROSS AREA. STILL SOME TIMING DIFFERENCES WITH STRONG
LOW PRESSURE AND COLD FRONT MOVING THROUGH CENTRAL IL WED NIGHT
AND SE IL THU MORNING.
LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
SHOWERS TO BECOME LIGHTER AND MORE SCATTERED IN NATURE THU NIGHT
AND FRI WITH STRONG STORM SYSTEM EXITING EAST OF IL. THOUGH STRONG
UPPER LEVEL TROF MOVING EAST INTO IL FRIDAY TO KEEP LOW CLOUDS
AROUND ALONG WITH CHANCES OF LIGHT SHOWERS AND BELOW NORMAL
TEMPERATURES. A FEW MODELS ARE SHOWING A SLIPPER SYSTEM BRINGING
SOME QPF INTO IL THIS WEEKEND THOUGH WILL ONLY CARRY SLIGHT CHANCE
POPS AT BEST SAT NIGHT AND SUNDAY. COLDEST TEMPS EXPECTED FRIDAY
AND FRI NIGHT WHEN LOWS COULD REACH AROUND FREEZING. TEMPS MODIFY
INTO THE 50S THIS WEEKEND WHICH IS ABOUT 10 DEGREES COLDER THAN
NORMAL.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ILZ027>031-036>038-
040>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1255 PM CDT SUN APR 14 2013
.UPDATE...
ISSUED AT 1249 PM CDT SUN APR 14 2013
UPDATED FORECAST MAINLY FOR THE POTENTIAL OF SQUALL LINE
DEVELOPMENT. LATEST VERSIONS OF THE HRRR LOOKED REASONABLE AND WITH
THE SLOWER MOVEMENT OF THE COLD FRONT IT APPEARS THERE IS A BETTER
CHANCE FOR SQUALL LINE DEVELOPMENT.
UPDATE ISSUED AT 455 AM CDT SUN APR 14 2013
HAVE UPDATED ZONES FOR CHANCE FOR LIGHT FREEZING RAIN IN FAR NORTH
EARLY TODAY...MAINLY BEFORE HEAVIER PRECIP ENTERS THE AREA. A
LIGHT GLAZING MAY OCCUR ON OBJECTS...BUT NOT MUCH EXPECTED ON
ROADS. OTHERWISE...GOING FORECAST REMAINS THE SAME.
&&
.SHORT TERM.../TODAY/...
ISSUED AT 351 AM CDT SUN APR 14 2013
STRONG WARM AIR ADVECTION AND UPPER LEVEL WARM FRONT CREATING AREA
OF CONVECTIVE SHOWERS ACROSS WESTERN IOWA EARLY THIS MORNING. WITH
THE AIRMASS QUITE COOL OVER IOWA THE AREA IS BEGINNING TO LOSE
LIGHTNING AND TRANSITION TO MODERATE SHOWERS. TEMPS ALOFT REMAIN
NEAR FREEZING AND HAVE HAD REPORTS OF SLEET MIXED IN WITH RAIN SO
HAVE UPDATED ZONES NORTH TO REFLECT THAT THROUGH 12Z. WILL ALSO NEED
TO WATCH A SMALL AREA OF NORTHERN IOWA FROM MASON CITY NORTHWARD FOR
THE NEXT FEW HOURS TO SEE IF ANY FREEZING RAIN DEVELOPS. IF IT
DOES...MAY NEED TO CONSIDER A BRIEF ADVISORY THERE...BUT WILL WAIT
FOR NOW AS WARM AIR MAY KEEP TEMPS JUST ABOVE FREEZING. AFTER
12Z...WARMING ALOFT AND NEAR THE SFC SHOULD RESULT IN ALL RAIN FOR
THE NORTHERN SECTIONS THOUGH IT WILL BE QUITE CHILLY EARLY IN THE
DAY WITH 30S TO AROUND 40 ACROSS NORTHERN IOWA. LOW STILL FORECAST
TO CUT ACROSS WESTERN IOWA AND THEN OCCLUDE BY 00Z OVER SOUTH
DAKOTA. STRONG H850 JET WILL ADVANCE INTO IOWA THIS MORNING WITH
WINDS OF 45 TO 50 KTS EXPECTED. SOUNDINGS SUGGEST THAT SOUTHEAST
WILL HAVE POTENTIAL TO REACH WIND ADVISORY CRITERIA GUSTS BY LATE
MORNING AND EARLY AFTERNOON... BEGINNING A BIT EARLIER IN THE
SOUTHWEST. EXPECTING WINDS TO REACH ABOUT 40+ FOR THE PERIOD FROM
15Z THROUGH 21Z WHEN THE FRONT SLIDES EAST AND FOR THE MOST PART ANY
PORTION OF THE ADVISORY WILL HAVE ABOUT 3 HOURS OF STRONGER WINDS.
TEMPS STILL EXPECTED TO MIX NICELY TODAY WITH BRIEF WARM SECTOR
IMPINGING ON THE REGION...AFTERNOON HIGHS WILL RISE INTO THE UPPER
60S TO LOWER 70S SOUTH AND REMAIN IN THE LOWER TO MID 50S IN THE FAR
NORTH. SHOWERS AND THUNDERSTORMS WILL DEVELOP AHEAD OF THE BOUNDARY
THIS AFTERNOON SOUTHEAST WITH COVERAGE INCREASING AFTER 18Z THERE.
WITH THE STORMS WILL COME A SMALL RISK OF GUSTY WINDS AND HAIL AND
PERHAPS AN ISOLATED STORM HAVING EITHER A SEVERE WIND GUST OR
MINIMALLY SEVERE HAIL BETWEEN 20 AND 00Z THIS AFTERNOON. RAINFALL
AMOUNTS OF .25 TO OVER .50 INCHES WILL ACCOMPANY THE AREA OF RAIN
AND MIXED SLEET HEADING NORTHEAST INTO NORTHERN IOWA THIS MORNING.
LATER THIS AFTERNOON THUNDERSTORMS WILL DEPOSIT ANOTHER .25 TO .50
INCHES OVER THE EAST/SOUTHEAST BY THIS EVENING.
.LONG TERM.../TONIGHT THROUGH SATURDAY/...
ISSUED AT 351 AM CDT SUN APR 14 2013
LOW PRESSURE OVER THE NORTHERN PLAINS WILL DEEPEN AS AN UPPER LEVEL
JET PUSHES ACROSS THE ROCKIES THEN ACROSS NEBRASKA AND INTO IOWA
TONIGHT. MEANWHILE NEAR THE SURFACE...LOW PRESSURE OVER EASTERN
NEBRASKA WILL LIFT NORTHEAST INTO IOWA BEFORE PIVOTING TO THE
NORTHWEST IN RESPONSE TO THE UPPER LEVEL FEATURES. THIS WILL MOVE A
WARM FRONT ACROSS THE FORECAST AREA THROUGH TONIGHT. STRONG THETA-E
ADVECTION OCCURS THIS AFTERNOON AND EVENING ALONG THIS BOUNDARY AND
STORMS SHOULD DEVELOP THIS AFTERNOON ACROSS EASTERN AND SOUTHERN
IOWA. SOME STORMS COULD BE STRONG IN THE VICINITY OF THE BOUNDARY
BUT THE BETTER INSTABILITY WILL BE FURTHER SOUTH. STILL...CANT RULE
OUT AN ISOLATED SEVERE STORM ACROSS THE SOUTHEAST. TO ADD TO THE
MIX...THIS EVENING AS THE SURFACE LOW PIVOTS BACK TO THE NORTHWEST
IT WILL MOVE A COLD FRONT THROUGH THE FORECAST AREA PROVIDING YET
ANOTHER BOUNDARY FOR ADDITIONAL THUNDERSTORM CHANCES THIS EVENING.
THE FRONT WILL SHIFT EAST OF THE FORECAST AREA AND THE DRY SLOT
PIVOTS INTO CENTRAL IOWA SOMETIME AROUND 06Z OR SHORTLY THEREAFTER
THUS PRECIP/THUNDERSTORM CHANCES WILL END BETWEEN 06Z AND 09Z.
COLDER AIR WILL THEN MOVE IN BEHIND THIS SYSTEM BUT TEMPERATURES
WILL HAVE QUITE A RANGE TONIGHT AS THE COLD AIR WILL NOT MAKE IT ALL
THE WAY ACROSS THE STATE. LOOKING FOR LOWS IN THE UPPER 20S
NORTHWEST TO THE MID 40S SOUTHEAST.
WE SHOULD DRY OUT SOME ON MONDAY BUT IT WILL BE PRETTY COOL WITH
HIGHS ONLY IN THE 40S AND 50S. A LARGE TROUGH WILL DEEPEN OVER THE
WEST COAST KEEPING THE CENTRAL CONUS IN A BROAD SOUTHWEST FLOW.
SEVERAL SHORTWAVES WILL EJECT OUT OF THE TROUGH BEFORE THE TROUGH
SHIFTS EAST LATER IN THE WEEK. THIS WILL KEEP PERIODIC CHANCES FOR
RAIN OF SNOW OVER CENTRAL IOWA THROUGH THE FORECAST PERIOD. BY
TUESDAY NIGHT AND WEDNESDAY THE TROUGH DEEPENS SUFFICIENTLY TO BRING
WARM ADVECTION BACK INTO IOWA AND MOISTURE AS WELL IN A SOUTHERLY
FLOW. SHOWERS AND THUNDERSTORMS WILL BE BACK IN THE FORECAST DURING
THIS TIMEFRAME. THE TROUGH IS STILL EXPECTED TO SHIFT EAST THROUGH
THURSDAY NIGHT KEEPING THE MID WEEK WET. PRECIP WILL CHANGE TO OR
MIX WITH SNOW WEDNESDAY NIGHT AND THURSDAY NIGHT BUT TEMPS SHOULD BE
WARM ENOUGH THROUGH THE DAY FOR RAIN WITH THE EXCEPTION OF THE FAR
NORTHWEST. WE GET A BIT OF A BREAK ON FRIDAY NIGHT FROM THE PRECIP
BUT AS AN UPPER LEVEL RIDGE BUILDS OVER THE ROCKIES ANOTHER SHORT
WAVE MAKES ITS WAY INTO THE MIDWEST FOR SATURDAY BRINGING AT LEAST
SMALL CHANCES FOR RAIN YET AGAIN. UNFORTUNATELY THIS PERIOD WILL BE
MARKED BY WELL BELOW NORMAL TEMPS AS WELL.
&&
.AVIATION...14/18Z
ISSUED AT 1249 PM CDT SUN APR 14 2013
WARM FRONT LIFTING NORTH AND HAS REACHED I-80 NOW. SCATTERED
SHOWERS CONTINUE OVER PARTS OF EASTERN IA IN THE WAA AREA BUD DO
NOT EXPECT TO SEE WIDESPREAD RESTRICTIONS WITH THESE. SOME VFR AND
LOCAL IFR CONDITIONS IN THE KMCW AND KALO AREAS EARLY THIS
AFTERNOON. COLD FRONT WILL MOVE ACROSS THE STATE LATE THIS
AFTERNOON AND EVENING WITH A POTENTIAL BROKEN TO SOLID SQUALL LIKE
DEVELOPING ALONG THE FRONT. THIS SHOULD EXIT THE TAF SITES BY 06Z.
SOME MVFR CIGS POST FROPA OVER THE NRN PART OF THE STATE...BUT
REMAINING VFR IN THE SOUTH.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR ADAMS-APPANOOSE-
CLARKE-DAVIS-DECATUR-LUCAS-MADISON-MAHASKA-MARION-MONROE-
RINGGOLD-TAYLOR-UNION-WAPELLO-WARREN-WAYNE.
&&
$$
UPDATE...MS APR 13
SHORT TERM...MS APR 13
LONG TERM...FAB
AVIATION...MS APR 13
AREA FORECAST DISCUSSION...UPDATED
NWS GRAY ME
911 AM EDT SUN APR 14 2013
.SYNOPSIS...
A TROUGH OF LOW PRESSURE REMAINS IN THE AREA TODAY WITH LOW PRESSURE
TO OUR NORTHWEST AND SOUTHEAST. HIGH PRESSURE BUILDS IN ON MONDAY
BEFORE A COLD FRONT APPROACHES THE REGION ON TUESDAY. THE COLD
FRONT WILL STALL TO OUR SOUTH ON WEDNESDAY...BEFORE RETURNING
NORTH AS A WARM FRONT ON THURSDAY. ANOTHER COLD FRONT WILL SLOWLY
APPROACH THE REGION FRIDAY...BEFORE CROSSING NEW ENGLAND ON SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
.UPDATE...
SHORT WAVE ROTATING OVER THE AREA IS FUELING SHOWERS ACROSS THE
AREA. HAVE EXTENDED POPS A BIT FARTHER SOUTH OVER THE NEXT FEW
HOURS AS HRRR INDICATES SOME DIURNAL SHOWERS MAY POP UP AS CLOUDS
THIN OUT OVER THE COASTAL PLAIN. STRIPE OF POSITIVE VORTICITY WILL
BE OVERHEAD FOR MUCH OF THE AFTERNOON. SKY COVER WAS ADJUSTED TO
REFLECT BREAKS ALREADY DEVELOPING OVER SOUTHERN NH.
&&
PREVIOUS DISCUSSION...UPR LOW PRES IS MEANDERING ACROSS SRN
CANADA ATTM. WEAK S/WV TROFS WILL CONTINUE TO ROTATE AROUND THE
PERIPHERY THRU THIS AFTERNOON. ONE S/WV HAS PULLED THRU WRN ME IN
THE LAST COUPLE OF HRS...WITH SHRA BRIEFLY COMING TO AN END BEHIND
IT. A SECOND S/WV WILL APPROACH OUT OF NY STATE EARLY THIS MORNING
AND CROSS THRU THE AREA THIS AFTERNOON. POP WILL GRADUALLY BE ON
THE INCREASE IN THE NEXT SEVERAL HRS...HOWEVER PCPN WILL BE FAIRLY
DISORGANIZED SO HAVE NOT GONE HIGHER THAN CHANCE OUTSIDE OF THE
HIGHER TERRAIN.
GRADIENT WILL BE WEAK ACROSS THE AREA AS S/WV PASSES OVERHEAD. AS
SUCH HI RES MODEL GUIDANCE SUGGEST THE DEVELOPMENT OF A SEA BREEZE
TODAY. HAVE COOLED TEMPS A LITTLE NEAR THE IMMEDIATE COASTLINE TO
ACCOUNT FOR THIS. HOWEVER...NWLY FLOW DEVELOPING BEHIND THE S/WV
WILL LIMIT THE INLAND EXTENT OF SEA BREEZE FNT. THIS SHOULD ALLOW
HIGH TEMPS TO CLIMB INTO THE 50S FOR SRN NH AND SWRN ME WITH SOME
PEEKS OF SUN LATE IN THE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
GRADUAL CLEARING CONTINUES INTO TONIGHT...WITH LOW TEMPS SLIPPING
DOWN TO NEAR 30 DEG. AS HIGH PRES BUILDS INTO THE AREA...UPSLOPE
SHWRS WILL ALSO WIND DOWN.
AS HIGH PRES SLIDES EWD INTO THE MARITIMES A WARM FNT WILL
APPROACH FROM THE W ON MON. ONSHORE FLOW WILL DOMINATE TO THE N OF
THE FNT...AND TEMPS WILL SUFFER BECAUSE OF IT. COASTAL ME WILL
STRUGGLE TO CLIMB TO 50 DEG WITH LLVL NELY FLOW. GUIDANCE IS IN
EXCELLENT AGREEMENT THAT WARMEST TEMPS WILL BE IN THE CT RIVER
VALLEY...WHERE AN ISOLD 60 DEG READING IS NOT OUT OF THE QUESTION
IF THE ENCROACHING CLOUD DECK REMAINS DIFFUSE ENOUGH. OTHERWISE
FNT WILL GRADUALLY LIFT THRU THE AREA INTO TUE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
A WARM FRONT WILL SLOWLY APPROACH THE REGION FROM THE WEST MONDAY
NIGHT. AS THE FRONT CROSSES NEW ENGLAND TUESDAY AFTERNOON AND
TUESDAY EVENING...MOST OF THE SHOWER ACTIVITY WILL BE CONFINED TO
THE NORTH AND MOUNTAINS.
FOR THE MOST PART...THE 00Z MODEL SUITE IS NOW PUSHING THE COLD
FRONT WELL SOUTH OF THE REGION WEDNESDAY. THERE IS SOME
DISAGREEMENT IN THE EURO CAMP...AS THE FRONT GETS HUNG UP OVER
SOUTHERN NEW ENGLAND DURING THIS TIME PERIOD.
HAVE OPTED FOR THE DRY SCENARIO ON WEDNESDAY. HOWEVER...THE FRONT
WILL RETREAT NORTHWARD ON THURSDAY...WITH THE GREATEST LIKELIHOOD
OF ANY SHOWER ACTIVITY BEING CONFINED TO THE FAR NORTH.
A SLOW MOVING COLD FRONT WILL APPROACH ON FRIDAY. WINDS WILL BE
VERY GUSTY OUT OF THE SOUTH AS THE GRADIENT INCREASES DURING THE
DAY. WIND OFF THE GULF OF MAINE SHOULD KEEP READINGS IN THE
60S...DESPITE H850 TEMPS AOA +10C OVER SOUTHERN AREAS. READINGS
ALONG THE COAST WILL LIKELY REMAIN IN THE 50S DUE TO THE COOL
ONSHORE FLOW.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
SHORT TERM...LOCAL IFR CONDS IN VALLEY FOG THIS MORNING WILL GIVE
WAY TO VFR CONDS THRU MON. SCT SHRA WILL CROSS THE AREA THIS
MORNING...BUT NO RESTRICTIONS ARE EXPECTED. NW WINDS MAY BRIEFLY
GUST AOA 17 KT THIS AFTERNOON...EXCEPT FOR KPWM AND KRKD WHERE SEA
BREEZE IS EXPECTED TO FORM.
LONG TERM...VFR MONDAY NIGHT...FOLLOWED BY CEILINGS LOWERING TO
MVFR BY TUESDAY INTO WEDNESDAY MORNING AS SHOWERS ARRIVE.
CONDITIONS WILL IMPROVE WEDNESDAY DURING THE DAY TO VFR. THE FRONT
WILL RETURN TO THE NORTH AS A WARM FRONT ON THURSDAY WITH PATCHY
MVFR CONDITIONS EXPECTED.
&&
.MARINE...
SHORT TERM...WINDS AND SEAS WILL REMAIN BLO SCA THRESHOLDS THRU MON.
LONG TERM...WINDS AND SEAS BUILD AGAIN ON TUESDAY TO NEARLY A
GALE AHEAD OF AN APPROACHING LOW PRESSURE SYSTEM.
&&
.FIRE WEATHER...
THE FIRE WEATHER DANGER WILL REMAIN LOW THROUGH MONDAY.SCATTERED
SHOWERS ARE EXPECTED TODAY. IN ADDITION WINDS WILL BE LIGHT AND
MINIMUM RH VALUES ABOVE 35 PERCENT.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
UPDATE...HANES
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
959 PM EDT MON APR 15 2013
.UPDATE...
THE BAND OF RAIN SHOWERS NOW EXTENDING FROM NRN IL INTO NE LOWER
MI IS ASSOCIATED WITH LOW TO MID TROPOSPHERIC FGEN ALONG A PLUME
OF DEEP LAYER MOISTURE. THUS FAR THE HIGHEST RETURNS HAVE BEEN
ALONG THE 700MB FRONT. THE 18Z NAM AND RECENT RAP ALL SUGGEST
A CONTRACTION OF THE LOWER TROPOSPHERIC THERMAL GRADIENT OVER THE
NEXT 2 TO 6 HOURS...WHICH SHOULD LEAD TO ENHANCED FGEN WITHIN THE
900-800MB LAYER. RECENT RADAR TRENDS OVER SW LOWER MI ARE IN
SUPPORT OF THIS. THERE ARE SOME INDICATIONS IN THE MODEL SOLUTIONS
THAT THE LOW LEVEL FGEN WILL FRACTURE AS IT TRAVERSES SE MI
OVERNIGHT...RAISING SOME CONCERNS THAT RAINFALL ACROSS THE FAR
EASTERN SECTIONS OF THE FORECAST AREA MAY NOT BE THAT
WIDESPREAD...PARTICULARLY FROM DETROIT DOWN TO MONROE AND ADRIAN.
THE EVENING UPDATE WILL REFLECT THIS IDEA BY A SUBTL LOWERING IN
POPS ACROSS THE FAR EAST. OTHERWISE...ONLY MINOR ADJUSTMENTS WILL
BE MADE TO THE GOING FORECAST.
&&
.AVIATION...ISSUED 701 PM EDT MON APR 15 2013
//DISCUSSION...
A COLD FRONT NOW OVER WRN LOWER MI WILL TRACK ACROSS MBS EARLY THIS
EVENING...THEN SLOWLY ADVANCE ACROSS SE MI OVERNIGHT...PASSING
THROUGH METRO DETROIT AROUND 09Z. A REGION OF SHOWERS WILL OCCUR
ALONG AND IN THE WAKE OF THIS COLD FRONT. THE ADDED LOW LEVEL
MOISTURE WILL RAPIDLY LOWER CEILINGS TO MVFR WITH SOME IFR
CONDITIONS POSSIBLE IN THE IMMEDIATE POST FRONTAL AIRMASS. THE
FRONTAL PASSAGE WILL ALSO BE MARKED BY AN ABRUPT SHIFT IN THE WINDS
TO THE W-NW. CONDITIONS ARE EXPECTED TO IMPROVE MARKEDLY LATE TUES
MORNING AS DRY AIR FUNNELS IN FROM THE WEST.
FOR DTW...WHILE SOME SHOWERS ARE POSSIBLE LATE THIS EVENING WITH A
REGION OF MOISTURE ADVECTION AHEAD OF THE FRONT...MORE SIGNIFICANT
LOWERING OF CEILINGS AND WIDESPREAD RAIN SHOWERS WILL HOLD OFF UNTIL
LATE TONIGHT/EARLY TUES MORNING GIVEN THE LATE ARRIVAL OF THE COLD
FRONT.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT LATE TONIGHT
THROUGH TUESDAY MORNING.
&&
.PREV DISCUSSION...ISSUED 300 PM EDT MON APR 15 2013
SHORT TERM...TONIGHT
FOR THE TIME BEING, SOUTHEAST MICHIGAN REMAINS FIRMLY EMBEDDED
WITHIN THE WARM SECTOR OF A FILLING CYCLONE LIFTING ACROSS NORTHERN
MINNESOTA. ONLY A VERY SLOW EASTWARD PROGRESSION OF THE ASSOCIATED
COLD FRONT IS FORECAST AS IT IS ALREADY IN THE PROCESS OF ALIGNING
ROUGHLY PARALLEL WITH MEAN DEEP LAYER FLOW. ALTHOUGH THE FRONT,
DRAPED FROM THE WESTERN LAKES ACROSS THE MID MS VALLEY, HAS BEEN
MOSTLY DRY THROUGH THE FIRST PART OF TODAY, ONGOING/DEVELOPING
SHOWERS ACROSS MO/IL ARE SYMPTOMATIC OF INCREASING MID-LEVEL
MOISTURE TRANSPORT THAT WILL FOSTER A STEADY INCREASE IN SHOWER
COVERAGE THIS AFTERNOON THROUGH TONIGHT. AS THIS OCCURS, LOW
AMPLITUDE ENERGY WITHIN PREVAILING WSW FLOW ALOFT WILL FACILITATE A
TIGHTENING OF THE UPPER MASS GRADIENT AND SUBSEQUENT JET CORE
DEVELOPMENT ACROSS THE STRAITS BY LATE TONIGHT. SUBTLE RIGHT
ENTRANCE DYNAMICS WILL AID HIGHER RAIN RATES TO THE WEST OF THE
SURFACE FRONT AND STORM TOTALS OF AT LEAST A QUARTER OF AN INCH
ACROSS THE SAGINAW VALLEY AND WESTERN THUMB. GIVEN THAT JET
SUPPORT/MID-LEVEL FGEN WILL BE RATHER BRIEF/TRANSIENT IN NATURE, THE
EXPECTATION IS FOR EASTERN AREAS TO SEE CLOSER TO 0.1" OR SO AS THE
FRONTAL ZONE BECOMES SEPARATED FROM THE BETTER UPPER SUPPORT AND
SPINS DOWN DURING ITS PUSH ACROSS THE FORECAST AREA. HEALTHY
MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE SURFACE FRONT
WARRANT CONTINUANCE OF CATEGORICAL POPS FOR ALL LOCATIONS. FORECAST
REASONING WITH REGARD TO LOW-END THUNDER POTENTIAL REMAINS UNCHANGED
AS PLUME OF MODEST H85-H7 CONDITIONAL INSTABILITY WILL BE CAPABLE OF
SUPPORTING A FEW RUMBLES OF THUNDER ACROSS SEMI OVERNIGHT.
TEMPERATURES WILL FALL AROUND 10+ DEGREES INTO THE 40S WITH THE
PASSAGE OF THE FRONT LATE TONIGHT.
LONG TERM...TUESDAY THROUGH MONDAY
AS STRONG SHORTWAVE FILLS AS IT LIFTS INTO QUEBEC...FRONTAL BOUNDARY
WILL SAG SOUTH OF THE CWA AND STALL OVER THE OHIO VALLEY WITHIN THE
BROAD WEST/SOUTHWEST UPPER FLOW WHICH ENCOMPASSES THE EASTERN CONUS
IS ADVANCE OF STRONG UPPER LEVEL STORM SYSTEM DIGGING THROUGH THE
WESTERN PART OF THE NATION. RELATIVELY MOIST/MILD AIR WILL OVERRUN
THIS SHALLOW BOUNDARY AND MAINTAIN THE CHANCE OF RAIN SHOWERS OVER
THE SOUTHERN CWA ON TUESDAY WITH THE SHOWER CHANCES SLOWLY EXPANDING
BACK TO THE NORTH INTO WEDNESDAY AS THE UPPER SYSTEM IN THE WEST
BEGINS TO EMERGE OVER THE CENTRAL/SOUTHERN PLAINS AND UPPER HEIGHTS
BUILD OVER THE REGION AND FORCE THE MILD/MOIST AIRMASS NORTHWARD
WITH TIME.
SHOWERS/THUNDERSTORMS WILL BECOME INCREASINGLY LIKELY AS THE WARM
FRONT LIFTS NORTH THROUGH THE AREA LATE WEDNESDAY INTO THURSDAY
NIGHT AND STALLS NEAR THE NORTHERN CWA AS THE PLAIN/S SYSTEM LIFTS
INTO THE GREAT LAKES. AS THIS SYSTEM DEEPENS AND APPROACHES THE
REGION...FORCING ALONG THE SOUTHWEST TO NORTHEAST ORIENTED FRONT
WILL INCREASE AND PROVIDE INCREASED LIFT. AT THE SAME TIME...AN
INCREASE IN OVERALL AVAILABLE MOISTURE CAN BE EXPECTED AS THE
SOUTHWEST FLOW INCREASES AND MOISTURE POOLING BECOMES ENHANCED WITH
CONVERGENCE ALONG THIS FRONTAL BOUNDARY.
WHILE THE ENTIRE AREA WILL SHARE IN THE HIGH LIKELIHOOD OF PERIODIC
RAIN SHOWERS AND EMBEDDED THUNDERSTORMS WITH HEAVY RAINFALL DURING
THIS TIME FRAME...MODELS ARE BECOMING INCREASINGLY CONSISTENT IN
FAVORING THE SAGINAW VALLEY/NORTHERN THUMB FOR THE MOST PERSIST
ACTIVITY (HENCE THE HEAVIEST TOTAL RAINFALL ON THE ORDER OF SEVERAL
INCHES). THIS AREA OF THE CWA TOOK THE BRUNT OF LAST WEEK/S HEAVY
RAINFALL WITH 3-5 INCHES...SO FLOODING COULD ONCE AGAIN BECOME A
CONCERN.
SHOWERS WILL LINGER INTO FRIDAY...BUT IT APPEARS A STRONG DRY SLOT
WILL STRIP AWAY DEEPER MOISTURE QUICKLY AS CENTER OF THE UPPER LEVEL
STORM SYSTEM LIFTS THROUGH THE UPPER MISSISSIPPI VALLEY INTO THE
NORTHERN GREAT LAKES. THIS WILL BRING AN END TO THE HEAVIER RAINFALL
EARLY IN THE DAY WITH JUST WIDELY SCATTERED SHOWERS POSSIBLE INTO
FRIDAY NIGHT. BY THAT TIME...ENOUGH COLD AIR WILL HAVE WRAPPED INTO
THE AREA AROUND THIS LOW PRESSURE TO CHANCE ANY SHOWERS TO LIGHT
SNOW SHOWERS.
THE PATTERN THEN MODERATES TEMPORARILY BY LATE THIS WEEKEND INTO
EARLY NEXT WEEK WITHIN SHORTWAVE RIDGING IN ADVANCE OF THE NEXT
STORM SYSTEM ORGANIZING OVER THE PLAIN STATES.
MARINE...
THE FRESH TO MODERATE SOUTHERLY BREEZE WILL PERSIST UNTIL THE
PASSAGE OF A COLD FRONT LATER TONIGHT. THE PASSAGE OF THE FRONT WILL
BRING ABOUT AN ABRUPT CHANGE IN WIND DIRECTION TO WNW BY LATE
TONIGHT INTO EARLY TUESDAY MORNING ALONG WITH A SLIGHT CHANCE FOR
THUNDERSTORMS. SHORT DURATION FETCH AND A LACK OF STRONGER WINDS
WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS ACROSS AREA
WATERS THROUGH WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......SC
AVIATION.....SC
SHORT TERM...JVC
LONG TERM....DG
MARINE.......JVC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
743 PM EDT MON APR 15 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 420 PM EDT MON APR 15 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR TROF
STRETCHING FM MN THRU THE PAC NW UPSTREAM OF UPR RDG OVER THE ERN
CONUS. SHRTWV THAT CAUSED WINTRY MIX OF PCPN SUN INTO THIS MRNG IS
LIFTING NEWD THRU MN ON THE ERN FLANK OF THE UPR TROF AXIS. DRY SLOT
ON THE ERN FLANK OF THIS DISTURBANCE HAS ADVECTED MUCH DRIER MID LVL
AIR OVER UPR MI WITH SW H7 WINDS UP TO 73 KTS AS SHOWN ON THE 12Z
GRB RAOB. SINCE WARM CONVEYOR BELT MSTR HAS ALSO SHIFTED TO THE E...
THE CWA IS PCPN FREE THIS AFTN. RETURN OF SUNSHINE UNDER THE DRY
SLOTTING OVER THE W AND CENTRAL HAS CAUSED TEMPS TO RECOVER TO MORE
SEASONABLE LVLS. OVER THE E...LO CLDS HAVE BEEN MORE PERSISTENT WITH
SSW LLVL FLOW OFF THE CHILLY LK MI WATERS AND LLVL MSTR SHOWN ON THE
12Z GRB RAOB. BKN SC HAS ALSO DVLPD OVER THE W AS DAYTIME HEATING
HAS DESTABILIZED LLVL LAPSE RATES WITH INFLUX OF LOWER H85 TEMPS AND
ARRIVAL OF MOISTER LLVL AIR DEPICTED ON THE 12Z MPX RAOB.
TNGT...SHRTWV/SFC LO IN MN ARE PROGGED TO SHIFT NEWD THRU NW
ONTARIO. ALTHOUGH SUPPORTING DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL
SLIDE TO THE NW OF UPR MI...THERE MAY BE ENUF MOISTENING OVER THE W
WITH THE SLOW ARRIVAL OF COLDER AIR TO JUSTIFY RETAINING FCST OF
SCHC POPS IN THAT AREA...ESPECIALLY OVERNGT WITH A WSHFT TO AN
UPSLOPE W COMPONENT COINCIDENT WITH LO PRES TROF PASSAGE TO THE S OF
LO MOVING THRU NW ONTARIO. ALTHOUGH THERE MAY BE MORE SC OVER THE CNTRL AS
WELL...THE TRANSITION TO A MORE W WIND SHOULD AID CLRG OVER THE E.
TUE...LO PRES TROF ON THE SW FLANK OF DEPARTING SHRTWV/SFC LO TOWARD
JAMES BAY WL CROSS UPR MI BY EARLY AFTN. ALTHOUGH THERE WL LIKELY BE
QUITE A BIT OF SC IN THE MOIST CYC W-SW SHIFTING NW FLOW...SHARP INVRN
NEAR H8 SHOWN ON FCST SDNGS IN THE ABSENCE OF ANY UPR SUPPORT WL
SQUASH POPS AWAY FM THE W...WHERE UPSLOPE FLOW MIGHT GENERATE A FEW
-SHSN IN THE MRNG. AS THE LLVL FLOW TRENDS MORE ACYC DURING THE AFTN
FOLLOWING THE TROF PASSAGE AND SE OF HI PRES BLDG TOWARD NW
ONTARIO...THE SC MAY TEND TO BREAK UP IN THE AFTN...ESPECIALLY
DOWNWIND OF LK SUP WITH SPRING STABILIZATION IN THE AFTN OFF THE
WATER. DEEP MIXING TO H8-85 WL SUPPORT MAX TEMPS APRCHG 50 OVER THE
SCENTRAL WITH DOWNSLOPE NW FLOW. AREAS NEAR LK SUP WL BE COOLER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 451 PM EDT MON APR 15 2013
THERE ARE A COUPLE OF PERIODS OF CONCERN IN THIS LONG TERM PERIOD.
THE FIRST WILL PUSH IN FROM THE SOUTHWEST WEDNESDAY EVENING THROUGH
THURSDAY MORNING...WITH A SECONDARY SURGE OF MOISTURE SLIDING ACROSS
UPPER MICHIGAN THURSDAY NIGHT INTO FRIDAY. LATE THIS WEEKEND INTO
EARLY NEXT WEEK MAY ALSO END UP BEING INTERESTING...WITH ANOTHER
SURGE OF WARM AIR PUSHES IN FROM THE SOUTH.
AT 00Z WEDNESDAY A WEAK SFC TROUGH MAY STILL BE OVER CENTRAL LAKE
SUPERIOR AND NORTHERN UPPER MICHIGAN...BUT THAT FEATURE SHOULD EXIT
QUICKLY AS THE LARGE AREA OF HIGH PRESSURE OVER CENTRAL CANADA
PUSHES INTO ONTARIO AND LAKE SUPERIOR OVERNIGHT. KEPT CONDITIONS DRY
FOR NOW...ALTHOUGH SOME OF THE SMALLER SCALE MODELS DID INDICATE A
FEW LIGHT FLURRIES OR SNOW SHOWERS. OTHERWISE...DRY CONDITIONS
SHOULD LINGER THROUGH WEDNESDAY MORNING...AS THE HIGH PRESSURE
SYSTEM SLOWLY EXITS TO EASTERN ONTARIO AND OVER JAMES BAY BY 00Z
THURSDAY.
WILL CONTINUE TO HEDGE THE FORECAST CLOSER TO THE ECMWF WITH THIS
PACKAGE UPDATE. ALTHOUGH IT IS A LITTLE WEAKER AND EASTWARD WITH
THE SURFACE LOW TO OUR SOUTH AND EAST DURING THE DAY THURSDAY...BOTH
THE GFS AND ECMWF HAVE THE SURFACE LOW OVER FAR EASTERN UPPER
MICHIGAN AT 18Z FRIDAY /ALTHOUGH THE GFS IS DEEPER WITH THE SYSTEM/.
PRECIPITATION TYPE AND AMOUNTS REMAIN A CONCERN...WITH RAIN MAINLY
CENTRAL AND EAST...CLOSER TO THE LOW. WEDNESDAY NIGHT STILL LOOKS
LIKE A POTENTIAL FOR FREEZING RAIN...WITH SURFACE TEMPERATURES OF
29-32F BETWEEN 01-11Z THURSDAY. WHILE THE TYPICAL ROADWAYS MAY STAY
WARM ENOUGH FOR WET CONDITIONS DUE TO LINGER SALT DEPOSITS ALREADY
ON THEM...AND BEING MORE WELL-TRAVELED. AS WE MOVE DEEPER INTO THE
SPRING SEASON IT BECOME INCREASINGLY DIFFICULT FOR ROADWAYS TO STAY
BELOW FREEZING FOR TOO LONG. STILL HAVE A GOOD CHANCE OF FREEZING
RAIN ACCUMULATING TO GENERALLY LESS THAN A TENTH OF AN INCH. KEPT
THE MENTION IN THE HWO AT THIS POINT. ALSO HAVE THE POTENTIAL FOR
2-4 INCHES OF HEAVY WET SNOW OVER THE HIGHER TERRAIN OF THE WEST
WEDNESDAY NIGHT...LINGERING INTO THURSDAY WITH A SMALL BREAK FIGURED
BEFORE WE COME UNDER THE INFLUENCE OF THE 500MB TROUGH AND COLDER
AIR PUSHING IN FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT.
NNE 850MB WINDS OF 30-50KT LOOK REALISTIC FROM 06-15Z
FRIDAY...BEFORE TURNING MORE NORTHERLY AS THE LOW PUSHES ACROSS
EASTERN UPPER MICHIGAN. INTRODUCED GALE FORCE VALUES TO PORTIONS OF
MAINLY CENTRAL LAKE SUPERIOR FRIDAY INTO FRIDAY EVENING...BUT WOULD
NOT BE SURPRISED IF WE NEED TO BUMP UP OUR FORECAST FOR THE NE WINDS
FUNNELING DOWN THE WESTERN HALF OF LAKE SUPERIOR EARLIER IN THE DAY.
THE WEST END OF THE CWA /GOGEBIC AND ONTONAGON COUNTIES/ WILL ALSO
HAVE THE BEST CHANCE OF LAKE EFFECT/LAKE ENHANCED SNOW
ACCUMULATIONS...WITH 850MB TEMPS GENERALLY COOLING BELOW -6C.
LIGHTER AMOUNTS ARE FIGURED EAST...WITH WARMER AIR WILL AROUND AND A
MIX OF RAIN OR SNOW POSSIBLE FAR EAST THROUGH THE DAY FRIDAY.
DRY WEATHER SHOULD BE THE RULE ONCE AGAIN STARTING SATURDAY AS HIGH
PRESSURE BUILDS IN AT THE SFC. HOWEVER WITH NW FLOW LINGERING ALOFT
AND N-NNW WINDS AT THE SURFACE...ALONG WITH 850MB TEMPS OF -11 TO
-14C...LINGERING SNOW SHOWERS WILL BE POSSIBLE EAST OF MARQUETTE
NEAR LAKE SUPERIOR INTO THE MID/LATE MORNING HOURS.
THERE ARE SIGNIFICANT TIMING DIFFERENCES WITH THE APPROACH OF THE
NEXT SYSTEM. THEY DO AGREE ON STRONG S WINDS AT 850MB...AGAIN
APPROACHING THE 40-55KT RANGE FROM MAINLY LATE SUNDAY AFTERNOON
THROUGH MONDAY MORNING...AS THE LLJ PUSHES W TO E ACROSS THE CWA.
THE MAIN ISSUE IS REGARDING THE TIMING OF THE NEXT SURGE OF
MOISTURE/PRECIPITATION...WHICH THE 15/12Z GFS IS MUCH MORE
PROGRESSIVE AND BRINGS IN MORNING TO THE WEST HALF. THIS IS APPROX 6
OR MORE HOURS FASTER THAN THE 15/06Z GFS RUN. THE 12Z ECMWF SHOWED A
SLOWER SOLUTION. GIVEN THE VARIABILITY SHOWN IN THE AVAILABLE
MODELS...IT SEEMS REASONABLE TO CONCENTRATE A BIT MORE ON THE NEAR
TERM...AND RUN WITH A CONTINUED CONSENSUS APPROACH AFTER 00Z MONDAY.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 741 PM EDT MON APR 15 2013
VFR CONDITIONS WILL BE THE RULE THRU MID EVENING AT KIWD/KCMX/KSAW.
THEN...AS MIDLEVEL LOW CURRENTLY JUST NW OF LAKE SUPERIOR CONTINUES
LIFTING ENE...LOW-LEVEL MOISTURE WRAPPING AROUND SYSTEM WILL LIKELY
BRING A RETURN OF MVFR CIGS TO KIWD/KCMX LATE THIS EVENING. APPROACH
AND PASSAGE OF SFC TROF LATE TONIGHT WILL BRING LOW MVFR CIGS
(PERHAPS IFR) TO KCMX ALONG WITH THE POSSIBILITY OF -SHSN/FLURRIES.
TROF SHOULD ALSO BRING HIGH MVFR CIGS TO KSAW AROUND DAYBREAK. MVFR
CIGS WILL LIFT/SCATTER OUT MID/LATE AFTN AT KIWD/KCMX. EXPECT CIGS
TO RISE TO VFR BY LATE MORNING AT KSAW.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT MON APR 15 2013
SHORT LIVED GALE EVENT WILL CONTINUE TO WIND DOWN EARLY THIS MORNING
ACROSS THE EAST HALF OF LAKE SUPERIOR AS THE LOW NEARS THE AREA AND
ALSO WEAKENS WHICH WILL WEAKEN THE PRESSURE GRADIENT. WINDS THEN
DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING OUT OF THE N
THURSDAY INTO FRIDAY WHEN GALES MAY BE POSSIBLE AGAIN AS ANOTHER
STRONG LATE SPRING SNOWSTORM AFFECTS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
147 PM EDT SUN APR 14 2013
.SYNOPSIS...
ISSUED AT 337 AM EDT SUN APR 14 2013
WARMER AIR MAKING A SURGE TOWARD THE AREA THIS MORNING AND EARLY
AFTERNOON WILL TOUCH OFF SOME PRECIPITATION ACROSS THE AREA. THIS
PRECIPITATION COULD START OFF AS RAIN...SNOW...AND EVEN A SLIGHT
CHANCE OF SLEET. THIS WILL MOVE NORTH OF THE AREA BY THIS EVENING.
WARMER AIR WILL SPREAD ACROSS THE AREA THROUGH THE DAY ON MONDAY.
A COLD FRONT WILL GRADUALLY MOVE THROUGH THE AREA DURING THE DAY ON
MONDAY. THE THREAT FOR SHOWERS WITH A FEW STORMS WILL INCREASE LATER
TONIGHT AND CONTINUE THROUGH MONDAY. OCCASIONAL PERIODS OF RAIN WILL
BE POSSIBLE THEN MID TO LATE WEEK THIS WEEK. WARMER AIR WILL
TEMPORARILY MOVE IN BEFORE COLDER AIR MOVES IN NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 838 AM EDT SUN APR 14 2013
SINCE IT WAS SNOWING WITH VISIBILITIES UNDER 2 MILES AS I DROVE
FROM GRANDVILLE TO M6 AND US-131 AND HOLLAND HAD 3SM -SN AND SINCE
THIS BAND IS MOVING NORTHEAST WITH THE WARM FRONT AND SINCE THE
LATEST HRRR (10Z) SHOWS THIS BAND DEVELOPING AS IT MOVES NORTH I
UPDATED THE FORECAST GRIDS TO SHOW A BAND PRECIPITATION MOVING
NORTH WITH TIME WITH LIKELY TO CONDITIONAL POPS. I USED THE TOP
DOWN METHOD TO CREATE THE PRECIPITATION TYPES SO WE NOW HAVE SNOW
TO RAIN AND SLEET IN THE GRIDS. BY EARLY AFTERNOON THE SOUTH EDGE
SHOULD BE NEAR ROUTE 10 AND BY THEN IT SHOULD BE ALL RAIN. I DO
NOT SEE ANY SIGNIFICANT ACCUMULATION WITH THIS AS IT WILL BE TO
SHORT LIVED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 337 AM EDT SUN APR 14 2013
THE MAIN CHALLENGES WITH THE SHORT TERM PORTION OF THE FCST INVOLVE
THE CHC OF PCPN TODAY ALONG WITH P-TYPE...AND THEN PCPN CHCS THE
REMAINDER OF THE PERIOD THROUGH TUE. ONE CHANGE IN THE FCST IS TO
LOWER PCPN CHANCES FOR TUE.
THE CLOUDS THAT WERE ASSOCIATED WITH THE BIG AND PERSISTENT LOW
AFFECTING THE AREA OVER THE PAST FEW DAYS HAVE BROKEN UP OVER THE
PAST COUPLE OF HOURS. THIS IS OCCURRING AS THE UPPER FLOW HAS BECOME
ANTI-CYCLONIC AND SFC RIDGING IS MOVING IN. THE NEXT BATCH OF CLOUDS
HAVE ALREADY STARTED TO MOVE IN ACROSS THE SW CORNER OF THE CWFA.
THE INCOMING CLOUDS ARE ASSOCIATED WITH RETURN FLOW IN THE MID
LEVELS ALREADY SETTING UP TO OUR SW THIS MORNING. JUST NORTH OF THE
DEVELOPING WARM FRONT FROM THE CENTRAL PLAINS TO THE MID MS RIVER
VALLEY IS A NARROW BAND OF SHOWERS AND ISOLATED STORMS. THIS BAND
WILL BE MAKING A RUN AT THE CWFA THIS MORNING. THE BEST LLJ AND
SURGE OF MOISTURE WILL TAKE PLACE WEST OF THE STATE. WE WILL NOT SEE
A WHOLE LOT OF MOISTURE BELOW 5K FEET...WHICH WILL HELP TO EAT AWAY
SOME OF THE PCPN THAT TRIES TO MOVE IN.
P-TYPE IS SOMEWHAT OF AN ISSUE WITH THIS PCPN. FCST SOUNDINGS
INDICATE THAT ALMOST THE ENTIRE CWFA IS COLD ENOUGH FOR SNOW. AS THE
WARM AIR SURGES IN...WE EXPECT TO SEE THE LEADING EDGE OF PCPN
INITIALLY START OUT AS SOME LIGHT SNOW. THERE COULD BE A BRIEF
PERIOD OF SOME SLEET AS FCST SOUNDINGS INDICATE AN ABOVE FREEZING
LAYER AT THE SFC AND ALOFT TRAPPING A COLD LAYER AROUND 2K FEET OR
SO THIS MORNING ACROSS THE SOUTH. THIS DOES NOT EXIST UP NORTH WHERE
THE PCPN WILL ARRIVE AFTER THE ELEVATED FREEZING LAYER MIXES OUT. AS
THE WARMER AIR GETS HERE...PCPN WILL CHANGE OVER TO RAIN BEFORE
ENDING.
WE WILL SEE A BREAK IN THE WEATHER THEN FROM LATE THIS AFTERNOON
UNTIL LATER TONIGHT. AT THAT TIME...WE WILL SEE THE LLJ AXIS MOVE IN
OUT AHEAD OF THE COLD FRONT THAT WILL BE APPROACHING THE AREA LATE.
THE MOISTURE TRANSPORT INTO THE AREA AND FRONT MOVING THROUGH WILL
BE SUFFICIENT FOR SPREADING SHOWERS IN FROM THE WEST THROUGH MON
MORNING. FCST SOUNDINGS INDICATE THAT SUFFICIENT ELEVATED
INSTABILITY WILL EXIST ENOUGH TO JUSTIFY A SLIGHT CHC OF THUNDER.
THE FRONT SHOULD CLEAR THE CWFA TO THE SE MON EVENING. PCPN CHCS
WILL DIMINISH MON NIGHT AS THE FRONT SINKS SOUTH INTO INDIANA AND
OHIO. IT WILL BE STALLING OUT AS IT WILL ALIGN WITH THE UPPER FLOW.
THE TREND IN THE MODELS IS FOR IT TO SINK A LITTLE FURTHER SOUTH
WITH A SLIGHTLY BETTER PUSH FROM THE WAVE MOVING THROUGH ONTARIO.
THIS SHOULD PROVIDE FOR A LITTLE LESS RAINFALL POTENTIAL ON TUE.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 AM EDT SUN APR 14 2013
GOOD MODEL CONSENSUS CONTINUES WITH THE 00Z GUIDANCE. MAIN IMPACT IN
THE EXTENDED IS MORE RAIN WHICH COULD CONTINUE SOME FLOODING INTO
NEXT WEEKEND. THE COLD FRONT STALLS ALONG OR JUST SOUTH OF THE
SOUTHERN FORECAST AREA WITH STORMS FIRING UP ALONG IT TUESDAY NIGHT.
THEN IT LIFTS NORTH AS A WARM FRONT WEDNESDAY AS ANOTHER SHORTWAVE
TROUGH APPROACHES. SFC LOW ARRIVES WEDNESDAY NIGHT ALONG WITH
HEAVIER RAIN AND SOME THUNDERSTORMS WITH POSSIBLY ANOTHER INCH OR
TWO OF RAIN BY THURSDAY.
COLDER WEATHER ON THE BACKSIDE OF THE LOW FOR THE END OF THE WEEK
WITH A FEW LEFT OVER RAIN AND SNOW SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 147 PM EDT SUN APR 14 2013
A NARROW BAND OF RAIN AND SNOW HAS MOVED OUT OF THE TAF SITES
EARLY THIS AFTERNOON. VFR CONDITIONS PREVAIL BEHIND THIS PCPN AND
THESE CONDITIONS ARE EXPECTED TO BE MAINTAINED FOR THE REST OF THE
AFTERNOON AND THROUGH MUCH OF THE OVERNIGHT. SE WINDS WILL REMAIN
BRISK AROUND 10-15 KTS INTO TONIGHT.
ANOTHER PERIOD OF RAIN WILL ARRIVE TOWARD DAYBREAK MONDAY. EXPECT
CONDITIONS TO LOWER TO MVFR AROUND DAYBREAK AND PERSIST THROUGHOUT
THE MORNING AND INTO MID DAY. WINDS WILL BECOME MORE SOUTHERLY AND
INCREASE TO 15 TO 20 KTS TOWARD MID DAY.
THERE IS THE CHANCE OF EMBEDDED THUNDERSTORMS AS THE RAIN ARRIVES
MONDAY MORNING. HOWEVER THESE LOOKS TO BE TOO ISOLATED TO INCLUDE
IN THE TAFS AT THIS POINT.
&&
.MARINE...
ISSUED AT 337 AM EDT SUN APR 14 2013
WE WILL BE ISSUING A SMALL CRAFT ADVISORY FOR THE ENTIRE NEARSHORE
WITH THIS FCST PACKAGE. STRONGER GRADIENT WILL MOVE IN LATER THIS
AFTERNOON AS THE WARM FRONT MOVES THROUGH THE AREA. THESE WINDS WILL
REMAIN UP UNTIL AND JUST AFTER THE FRONT MOVES THROUGH MON
AFTERNOON. WAVES WILL NOT BE A BIG PROBLEM INITIALLY AS THE WIND
WILL BE OFFSHORE. WINDS WILL EVENTUALLY SHIFT TO THE SOUTH/SOUTHWEST
AND WAVES WILL BUILD SOME AT THAT POINT.
&&
.HYDROLOGY...
ISSUED AT 337 AM EDT SUN APR 14 2013
NUMEROUS RIVER ADVISORIES AND WARNINGS REMAIN IN EFFECT...AND WILL
CONTINUE INTO THIS COMING WEEK. IT APPEARS THAT THE CREST ON THE
GRAND RIVER IS NEAR ADA AND WILL CONTINUE DOWNSTREAM OVER THE NEXT
FEW DAYS.
THE MAIN HYDRO CONCERN IN THE FCST IS THE ADDITIONAL RAINFALL
EXPECTED THIS WEEK AS WE WILL ONCE AGAIN BE AFFECTED BY AN UNSETTLED
AND WET PATTERN. THE AREA COULD BE LOOKING AT ANOTHER COUPLE OF
INCHES OF RAINFALL OVER THE NEXT WEEK WHICH WOULD ONLY EXACERBATE
ANY PROBLEMS THAT WILL REMAIN AS THE RAIN ARRIVES. THE POSITIVE SIDE
TO THIS COMING WEEK IS THAT FCST RAINFALL AMOUNTS IN GENERAL HAVE
DIMINISHED A LITTLE BIT. STILL A BIT OF UNCERTAINTY AS TO EXACTLY
HOW MUCH RAIN WE WILL SEE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT MONDAY FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...OSTUNO
AVIATION...JK
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
839 AM EDT SUN APR 14 2013
.SYNOPSIS...
ISSUED AT 337 AM EDT SUN APR 14 2013
WARMER AIR MAKING A SURGE TOWARD THE AREA THIS MORNING AND EARLY
AFTERNOON WILL TOUCH OFF SOME PRECIPITATION ACROSS THE AREA. THIS
PRECIPITATION COULD START OFF AS RAIN...SNOW...AND EVEN A SLIGHT
CHANCE OF SLEET. THIS WILL MOVE NORTH OF THE AREA BY THIS EVENING.
WARMER AIR WILL SPREAD ACROSS THE AREA THROUGH THE DAY ON MONDAY.
A COLD FRONT WILL GRADUALLY MOVE THROUGH THE AREA DURING THE DAY ON
MONDAY. THE THREAT FOR SHOWERS WITH A FEW STORMS WILL INCREASE LATER
TONIGHT AND CONTINUE THROUGH MONDAY. OCCASIONAL PERIODS OF RAIN WILL
BE POSSIBLE THEN MID TO LATE WEEK THIS WEEK. WARMER AIR WILL
TEMPORARILY MOVE IN BEFORE COLDER AIR MOVES IN NEXT WEEKEND.
&&
.UPDATE...
ISSUED AT 838 AM EDT SUN APR 14 2013
SINCE IT WAS SNOWING WITH VISIBILITIES UNDER 2 MILES AS I DROVE
FROM GRANDVILLE TO M6 AND US-131 AND HOLLAND HAD 3SM -SN AND SINCE
THIS BAND IS MOVING NORTHEAST WITH THE WARM FRONT AND SINCE THE
LATEST HRRR (10Z) SHOWS THIS BAND DEVELOPING AS IT MOVES NORTH I
UPDATED THE FORECAST GRIDS TO SHOW A BAND PRECIPITATION MOVING
NORTH WITH TIME WITH LIKELY TO CONDITIONAL POPS. I USED THE TOP
DOWN METHOD TO CREATE THE PRECIPITATION TYPES SO WE NOW HAVE SNOW
TO RAIN AND SLEET IN THE GRIDS. BY EARLY AFTERNOON THE SOUTH EDGE
SHOULD BE NEAR ROUTE 10 AND BY THEN IT SHOULD BE ALL RAIN. I DO
NOT SEE ANY SIGNIFICANT ACCUMULATION WITH THIS AS IT WILL BE TO
SHORT LIVED.
&&
.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 337 AM EDT SUN APR 14 2013
THE MAIN CHALLENGES WITH THE SHORT TERM PORTION OF THE FCST INVOLVE
THE CHC OF PCPN TODAY ALONG WITH P-TYPE...AND THEN PCPN CHCS THE
REMAINDER OF THE PERIOD THROUGH TUE. ONE CHANGE IN THE FCST IS TO
LOWER PCPN CHANCES FOR TUE.
THE CLOUDS THAT WERE ASSOCIATED WITH THE BIG AND PERSISTENT LOW
AFFECTING THE AREA OVER THE PAST FEW DAYS HAVE BROKEN UP OVER THE
PAST COUPLE OF HOURS. THIS IS OCCURRING AS THE UPPER FLOW HAS BECOME
ANTI-CYCLONIC AND SFC RIDGING IS MOVING IN. THE NEXT BATCH OF CLOUDS
HAVE ALREADY STARTED TO MOVE IN ACROSS THE SW CORNER OF THE CWFA.
THE INCOMING CLOUDS ARE ASSOCIATED WITH RETURN FLOW IN THE MID
LEVELS ALREADY SETTING UP TO OUR SW THIS MORNING. JUST NORTH OF THE
DEVELOPING WARM FRONT FROM THE CENTRAL PLAINS TO THE MID MS RIVER
VALLEY IS A NARROW BAND OF SHOWERS AND ISOLATED STORMS. THIS BAND
WILL BE MAKING A RUN AT THE CWFA THIS MORNING. THE BEST LLJ AND
SURGE OF MOISTURE WILL TAKE PLACE WEST OF THE STATE. WE WILL NOT SEE
A WHOLE LOT OF MOISTURE BELOW 5K FEET...WHICH WILL HELP TO EAT AWAY
SOME OF THE PCPN THAT TRIES TO MOVE IN.
P-TYPE IS SOMEWHAT OF AN ISSUE WITH THIS PCPN. FCST SOUNDINGS
INDICATE THAT ALMOST THE ENTIRE CWFA IS COLD ENOUGH FOR SNOW. AS THE
WARM AIR SURGES IN...WE EXPECT TO SEE THE LEADING EDGE OF PCPN
INITIALLY START OUT AS SOME LIGHT SNOW. THERE COULD BE A BRIEF
PERIOD OF SOME SLEET AS FCST SOUNDINGS INDICATE AN ABOVE FREEZING
LAYER AT THE SFC AND ALOFT TRAPPING A COLD LAYER AROUND 2K FEET OR
SO THIS MORNING ACROSS THE SOUTH. THIS DOES NOT EXIST UP NORTH WHERE
THE PCPN WILL ARRIVE AFTER THE ELEVATED FREEZING LAYER MIXES OUT. AS
THE WARMER AIR GETS HERE...PCPN WILL CHANGE OVER TO RAIN BEFORE
ENDING.
WE WILL SEE A BREAK IN THE WEATHER THEN FROM LATE THIS AFTERNOON
UNTIL LATER TONIGHT. AT THAT TIME...WE WILL SEE THE LLJ AXIS MOVE IN
OUT AHEAD OF THE COLD FRONT THAT WILL BE APPROACHING THE AREA LATE.
THE MOISTURE TRANSPORT INTO THE AREA AND FRONT MOVING THROUGH WILL
BE SUFFICIENT FOR SPREADING SHOWERS IN FROM THE WEST THROUGH MON
MORNING. FCST SOUNDINGS INDICATE THAT SUFFICIENT ELEVATED
INSTABILITY WILL EXIST ENOUGH TO JUSTIFY A SLIGHT CHC OF THUNDER.
THE FRONT SHOULD CLEAR THE CWFA TO THE SE MON EVENING. PCPN CHCS
WILL DIMINISH MON NIGHT AS THE FRONT SINKS SOUTH INTO INDIANA AND
OHIO. IT WILL BE STALLING OUT AS IT WILL ALIGN WITH THE UPPER FLOW.
THE TREND IN THE MODELS IS FOR IT TO SINK A LITTLE FURTHER SOUTH
WITH A SLIGHTLY BETTER PUSH FROM THE WAVE MOVING THROUGH ONTARIO.
THIS SHOULD PROVIDE FOR A LITTLE LESS RAINFALL POTENTIAL ON TUE.
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 337 AM EDT SUN APR 14 2013
GOOD MODEL CONSENSUS CONTINUES WITH THE 00Z GUIDANCE. MAIN IMPACT IN
THE EXTENDED IS MORE RAIN WHICH COULD CONTINUE SOME FLOODING INTO
NEXT WEEKEND. THE COLD FRONT STALLS ALONG OR JUST SOUTH OF THE
SOUTHERN FORECAST AREA WITH STORMS FIRING UP ALONG IT TUESDAY NIGHT.
THEN IT LIFTS NORTH AS A WARM FRONT WEDNESDAY AS ANOTHER SHORTWAVE
TROUGH APPROACHES. SFC LOW ARRIVES WEDNESDAY NIGHT ALONG WITH
HEAVIER RAIN AND SOME THUNDERSTORMS WITH POSSIBLY ANOTHER INCH OR
TWO OF RAIN BY THURSDAY.
COLDER WEATHER ON THE BACKSIDE OF THE LOW FOR THE END OF THE WEEK
WITH A FEW LEFT OVER RAIN AND SNOW SHOWERS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 838 AM EDT SUN APR 14 2013
I UPDATED THE MKG AND GRR TAFS SHOW SHOW THE BAND OF SNOW TO RAIN
MOVING THROUGH THOSE TAF SITES. LIKELY I WILL HAVE TO INCLUDE LAN
IN THIS PRECIPITATION BAND TOO. ONCE THIS MOVES THROUGH VFR SHOULD
PREVAIL THE REST OF TODAY. IT WILL BECOME WINDY TOO.
&&
.MARINE...
ISSUED AT 337 AM EDT SUN APR 14 2013
WE WILL BE ISSUING A SMALL CRAFT ADVISORY FOR THE ENTIRE NEARSHORE
WITH THIS FCST PACKAGE. STRONGER GRADIENT WILL MOVE IN LATER THIS
AFTERNOON AS THE WARM FRONT MOVES THROUGH THE AREA. THESE WINDS WILL
REMAIN UP UNTIL AND JUST AFTER THE FRONT MOVES THROUGH MON
AFTERNOON. WAVES WILL NOT BE A BIG PROBLEM INITIALLY AS THE WIND
WILL BE OFFSHORE. WINDS WILL EVENTUALLY SHIFT TO THE SOUTH/SOUTHWEST
AND WAVES WILL BUILD SOME AT THAT POINT.
&&
.HYDROLOGY...
ISSUED AT 337 AM EDT SUN APR 14 2013
NUMEROUS RIVER ADVISORIES AND WARNINGS REMAIN IN EFFECT...AND WILL
CONTINUE INTO THIS COMING WEEK. IT APPEARS THAT THE CREST ON THE
GRAND RIVER IS NEAR ADA AND WILL CONTINUE DOWNSTREAM OVER THE NEXT
FEW DAYS.
THE MAIN HYDRO CONCERN IN THE FCST IS THE ADDITIONAL RAINFALL
EXPECTED THIS WEEK AS WE WILL ONCE AGAIN BE AFFECTED BY AN UNSETTLED
AND WET PATTERN. THE AREA COULD BE LOOKING AT ANOTHER COUPLE OF
INCHES OF RAINFALL OVER THE NEXT WEEK WHICH WOULD ONLY EXACERBATE
ANY PROBLEMS THAT WILL REMAIN AS THE RAIN ARRIVES. THE POSITIVE SIDE
TO THIS COMING WEEK IS THAT FCST RAINFALL AMOUNTS IN GENERAL HAVE
DIMINISHED A LITTLE BIT. STILL A BIT OF UNCERTAINTY AS TO EXACTLY
HOW MUCH RAIN WE WILL SEE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 8 PM EDT MONDAY
FOR LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...OSTUNO
AVIATION...WDM
HYDROLOGY...NJJ
MARINE...NJJ
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1257 AM EDT SUN APR 14 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 415 PM EDT SAT APR 13 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOWS CLOSED LO
CENTERED OVER ONTARIO TO THE S OF PERSISTENT BLOCKING RDG OVER NE
CANADA IN PREVAILING NEGATIVE NAO PATTERN. WITH DEEP MSTR SHOWN ON
12Z INL/GRB RAOBS...CYC FLOW...H85-7 COLD POCKET WITH H85 TEMPS AS
LO AS -10C TO -12C OVER THE WRN CWA...AND SHRTWVS ROTATING ARND THE
MAIN CLOSED LO...CLDS AND SHSN HAVE LINGERED OVER UPR MI...E
SPECIALLY ALONG SFC LO PRES TROF ASSOCIATED WITH ONE OF THESE
SHRTWVS THAT IS CROSSING THE CWA EARLY THIS AFTN. TEMPS REMAIN WELL
BLO NORMAL FOR MID APRIL. OVER FAR WRN MN INTO THE NRN PLAINS...A
SFC RDG AXIS AND DRY MID LVL AIR SHOWN ON THE 12Z BISMARCK RAOB ARE
CAUSING DRY WX EVEN THOUGH SOME LO CLDS LINGER WITH MSTR TRAPPED BLO
INVRN BASE AT H8 SHOWN ON THE BISMARCK SOUNDING. ANOTHER POWERFUL
SHRTWV IS MOVING ONSHORE INTO THE PAC NW WITH 00Z-12Z H3-5 HGT FALLS
UP TO 150-200M.
MAIN FCST CONCERNS THRU TNGT ARE FOCUSED ON SHSN/CLD TRENDS AS THE
UPR LO OVER ONTARIO SLOWLY FILLS AND SHIFTS TO THE E. FOCUS ON
SUN/SUN NGT SHIFTS TO TIMING AND IMPACT OF SHRTWV NOW MOVING INTO
THE PAC NW.
LATE TODAY/TNGT...AS UPR LO IN ONTARIO SLOWLY WEAKENS...H5 HGT IS
PROGGED TO RISE 120M OVER UPR MI BTWN 00Z-12Z SUN UNDER VIGOROUS
DEEP LYR QVECTOR DVGC. AS THE CYC NW FLOW WEAKENS...EXPECT LINGERING
SHSN LATE THIS AFTN/EVNG TO DIMINISH STEADILY THRU THE NGT AND END
IN THE EARLY MRNG HRS ON SUN. WITH SOME CLRG LATE AT LEAST OVER THE
W AND CENTRL AND LGT WINDS UNDER THE SFC RDG AXIS...EXPECT TEMPS TO
FALL INTO THE TEENS...WELL BLO NORMAL FOR THE SEASON. WITH CLDS/LLVL
MSTR LINGERING LONGER IN A PERSISTENT NW FLOW OVER THE E...THOSE
AREAS WL BE WARMER.
SUN/SUN NGT...EXPECT A DRY START TO THE DAY WITH SFC HI PRES RDG
SLOWLY DEPARTING TO THE E. BUT ANY MRNG SUNSHINE WL QUICKLY FADE
BEHIND INCRSG CLDS AS VIGOROUS ISENTROPIC ASCENT/DEEPER MSTR/SW FLOW
ALF BTWN THE DEPARTING HI AND INCRSG NEGATIVELY TILTED SHRTWV/SFC LO
MOVING THRU THE NRN PLAINS AND TOWARD MN LATE IN THE DAY OVERSPREADS
UPR MI. AS UPR DVGC/BAND OF H85-7 FGEN AHEAD OF ATTENDANT WARM FNT
MOVES IN AFT 18Z...EXPECT PCPN TO OVERSPREAD THE CWA BY 00Z MON...
ESPECIALLY OVER THE W HALF CLOSER TO SHARPER DYNAMICS AND WHERE
MOISTENING/H85 MSTR CNVGC IS MOST IMPRESSIVE. PTYPE WL BE A CONCERN
SUN AFTN/EVNG. NAM/GFS FCST SDNGS INDICATE SATURATED TEMP PROFILE WL
AT LEAST INITIALLY BE COMPLETELY SUB ZERO...BUT THEN SHOW ELEVATED
WARM LYR ABV SUB ZERO NEAR SFC LYR. WITH ELEVATED WARMING INITIALLY
LIFTING TEMPS ABV 0C IN THE H8-75 LYR...SUSPECT SLEET WL MIX WITH
THE SN. THESE FCST SDNGS ALSO SUG PCPN MAY BE AT LEAST MIXED WITH
SOME FZRA FOR A TIME LATE IN THE AFTN/EVNG OVER AT LEAST THE HIER
TERRAIN OF THE W HALF AS THE ELEVATED WARM LYR DEEPENS AND TEMPS IN
THE LOWER LYR WARM TOO MUCH FOR DROPS TO REFREEZE. BUT THESE SDNGS
ALSO APPEAR TO UNDERDO THE SFC WARMING IN THE AFTN FOLLOWING AT
LEAST SOME MRNG SUNSHINE. WITH SOME LINGERING LLVL DRY AIR...
EVAPORATIVE COOLING COULD MAINTAIN SUB 32 NEAR SFC WBLB TEMPS. BUT
THE FCST NEAR SFC SE FLOW IN THE ABSENCE OF HI PRES CENTER OVER
ONTARIO AS WELL AS ARRIVAL OF PCPN AT MAX HEATING TIME THIS LATE IN
THE SEASON WOULD ALSO TEND TO MINIMIZE THIS THREAT. HIER GFS MOS
TEMPS SEEM MORE APPROPRIATE FOR THE TEMPS FCST THAN RAW MODEL
GUIDANCE. FOR NOW...WL FCST A SN/SLEET MIX AT THE ONSET
TRANSITIONING TO RA SUN EVNG AS MUCH WARMER/MSTR LLVL AIR SURGES
INTO THE UPR LKS ON THE HEELS OF H85 SW WINDS FCST UP TO 60-70KTS BY
06Z MON. EXPECT LITTLE IF ANY FALL OF TEMPS SUN NGT. THE NW CWA WL
HAVE THE BEST CHC FOR SEEING A LONGER PERIOD OF WINTRY PCPN WITH
H85-75 TEMPS REMAINING BLO 0C THERE FOR A LONGER TIME. NOT OUT OF
THE QUESTION ADVY SN MAY FALL OVER THE HIER TERRAIN OF THE KEWEENAW
SUN AFTN/EVNG. NEGATIVELY TILTED APPEARANCE OF SHRTWV/VERY DIFFLUENT
SW FLOW ALF/MSTR SURGE WITH FCST PWAT 0.75 TO 1 INCH SUN EVNG...OR
UP TO 200 PCT OF NORMAL...INDICATE QPF NEAR 1 INCH IN SOME PLACES IS
ON TRACK. RUNOFF FM THIS RA IN THE PRESENCE OF LINGERING SN PILES
MAY CAUSE SOME PONDING OF WATER. ALTHOUGH FCST H85-5 LAPSE RATES ARE
NOT MUCH MORE UNSTABLE THAN MOIST ADIABATIC...DECIDED TO INCLUDE
MENTION OF ELEVATED TS UNDER THE MOST IMPRESSIVE MOISTENING/AXIS OF
H85 LLJ GIVEN IMPRESSIVE DYNAMICS/NEGATIVE TILT OF SHRTWV. ARRIVAL
OF DRY SLOT SUN NGT WL DIMINISH POPS SW-NE AFTER THE EVNG. IN
FACT...FCST SDNGS INDICATE THERE MAY BE SOME CLRG OVER THE SW LATE.
.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 415 PM EDT SAT APR 13 2013
ACTIVE PATTERN ACROSS THE CONUS CONTINUES INTO NEXT WEEKEND AS A
LARGE SCALE UPPER TROUGH MOVES FROM THE W COAST MON TO THE CENTRAL
CONUS BY NEXT SAT...WITH PIECES OF SMALLER SCALE ENERGY EJECTING OFF
THE TROUGH THROUGH THE REGION.
STARTING THE PERIOD OFF 12Z MON...A STACKED CLOSED LOW WILL BE OVER
NRN MN WITH AN OCCLUDED FRONT FROM THE LOW TO NRN LAKE
SUPERIOR...AND THE ASSOCIATED WARM FRONT EXTENDING E FROM NRN LAKE
SUPERIOR INTO ONTARIO AND THE COLD FRONT FROM NRN LAKE SUPERIOR TO
FAR ERN UPPER MI. AT THIS POINT...THE PRECIP THAT MOVED OVER THE CWA
AHEAD OF THE COLD FRONT WILL BE MOSTLY E OF THE CWA. THE DRY SLOT
BEHIND THE COLD FRONT WILL BRING VERY DRY AIR INITIALLY THROUGH MOST
OF THE SOUNDING...BUT WRAP AROUND LOW LEVEL MOISTURE BELOW 800MB WILL
RETURN TO AT LEAST NW UPPER MI /MODELS DIFFER ON THE AREAL EXTENT OF
THE MOISTURE/ AS THE LOW MOVES N OF LAKE SUPERIOR TO JAMES BAY BY
12Z TUE. THIS MAY RESULT IN SOME CONVECTIVE WINTRY MIX SHOWERS WHERE
THERE IS SUFFICIENT LOW LEVEL MOISTURE TO TAP INTO STEEP LOW LEVEL
LAPSE RATES...MAINLY MON INTO EARLY MON NIGHT. WILL INTRODUCE SOME
LOW END POPS FOR THIS POSSIBILITY TO NW UPPER MI. WITH THE STEEP LOW
LEVEL LAPSE RATES...WE SHOULD SEE MIXING TO AROUND 800MB ON
MON...AND WITH SW 800-900MB WINDS AOA 40KTS...IT WILL MAKE FOR GUSTY
SFC WINDS. MAY END UP NEEDING A WIND ADVISORY IN SOME
LOCATIONS...BUT TOO EARLY TO SAY WHERE AT THIS POINT AS MODELS DO
VARY IN STRENGTH AND LOCATION OF BEST LOW LEVEL WINDS. COULD ALSO
SEE SOME DOWNSLOPE ENHANCEMENT OF THE WINDS...ESPECIALLY NEAR LAKE
SUPERIOR ON MARQUETTE COUNTY WITH THE SW WINDS.
EVEN THOUGH 850MB TEMPS DROP BY 7C OR MORE FROM SUN NIGHT INTO
MON...SHOULD STILL BE ABLE TO SEE TEMPS WARM INTO THE 40S /EVEN
AROUND 50 OVER THE SCENTRAL CWA/ MON AFTERNOON DUE TO GOOD LOW LEVEL
MIXING MIXING. THESE WARMER TEMPS AND GUSTY WINDS...COMBINED WITH
SUNSHINE /ESPECIALLY OVER THE CENTRAL AND ERN CWA/ AND RAIN SUN
NIGHT...COULD SEE SOME MELTING OF THE SNOWPACK MON. PROBABLY WILL
NOT LOSE TOO MUCH SNOW PACK...BUT SOME REDUCTION IS CERTAINLY
POSSIBLE.
THE FRONTAL ZONE STALLS WELL TO OUR S THROUGH TUE NIGHT AS UPPER
RIDGING BUILDS OVER THE CWA. THE NRN STREAM JET THEN PUSHES THROUGH
THE CWA TUE NIGHT AS THE UPPER TROUGH OVER THE WRN CONUS SHARPENS UP
AND MOVES TO THE INTERMOUNTAIN WEST. NRN AND SRN STREAM INTERACTION
ALONG THE SRN END OF THE TROUGH WILL CAUSE IT TO DEEPEN AND SHARPEN
UP FURTHER AS IT MOVES E FROM HUDSON BAY TO MN TO TX BY 00Z FRI AS
UPPER RIDGING BUILDS E OF THE CWA. BY LATE WED...WITH THE PRESSURE
GRADIENT TIGHTENING...THE NOW PHASED SRN AND NRN JET STREAM ARCING
FROM W TO N OF THE CWA WILLS STRENGTHEN TO AOA 120KTS. THIS LEADS TO
RAPID SFC CYCLOGENESIS ALONG THE FRONTAL ZONE OVER MO. THE 850MB
FRONTAL ZONE WILL MOVE N INTO THE CWA WED...AND WHEN COMBINED WITH
THE FORCING FROM THE RIGHT ENTRANCE REGION OF THE UPPER JET WILL
LEAD TO PRECIP BY WED AFTERNOON. THE EXACT PLACEMENT AND TYPE OF
PRECIP REMAINS IN QUESTION DUE TO MODEL DISAGREEMENT...BUT GENERALLY
EXPECT SNOW OVER THE NW CWA AND RAIN OVER THE SE CWA...AND THIS
PRECIP SHOULD BE RELATIVELY MINOR ACCUMULATION WISE. PRECIP AMOUNTS
THEN BECOME MORE OF A CONCERN WED NIGHT AND THU AS THE SFC LOW MOVES
ACROSS LAKE MI AND LOWER MI LATE WED NIGHT INTO THU. THE 12Z/13 GFS
AND 00Z/13 ECMWF AGREE PRETTY WELL ON BRINGING THE SFC LOW ACROSS
NRN LOWER MI...BUT THE ECMWF IS ABOUT 6 HOURS FASTER THAN THE GFS AND
NOT AS DEEP WITH THE SFC LOW. OVERALL...A MINOR DIFFERENCE THIS FAR
OUT WITH THE VOLATILE NATURE OF THIS TYPE OF SYSTEM. THINK THAT
MODELS ARE NOT SETTLED AND THINGS WILL CHANGE OVER THE NEXT FEW
DAYS...BUT THE GENERAL IDEA SEEMS GOOD. AT THIS POINT...THERMAL
FIELDS ARE SIMILAR BETWEEN THE MODELS...WITH TEMPS COLD ENOUGH FOR
MAINLY SNOW OVER THE NW CWA...AND MAINLY RAIN OVER THE SE CWA...AT
LEAST UNTIL COLD AIR ARRIVES LATE THU INTO THU NIGHT. SIGNIFICANT
PRECIP AMOUNTS WILL BE POSSIBLE AS MODELS SHOW BETWEEN 0.3 INCHES
AND AROUND 1 INCH OF QPF...BUT VARY ON THE EXACT PLACEMENT OF THIS
PRECIP. STILL SOMETHING TO KEEP A CLOSE EYE ON.
BY LATE THU INTO FRI...ADDITIONAL ENERGY ROUNDING THE BASE OF THE
UPPER TROUGH CAUSES THE SFC LOW TO STALL SOME /OR MORE REDEVELOP ON
THE SW SIDE/. THE MAIN IMPACT THIS HAS ON OUR WEATHER IS TO KEEP
BETTER MOISTURE AND A SFC TROUGH STRETCHED BACK ACROSS LAKE SUPERIOR
AS THE UPPER TROUGH AND MUCH COLDER AIR MOVES ACROSS THE CWA. IF
THIS DOES INDEED COME TO REALITY...LAKE EFFECT SNOW WOULD BE THE
RESULT AS 850MB TEMPS FALL TO AROUND -13C AHEAD OF THE UPPER TROUGH.
LES SHOULD THEN CONTINUE INTO AT LEAST PART OF SATURDAY...BUT
CONFIDENCE IN OVERALL PATTERN DECLINES RAPIDLY THROUGH THE DAY SAT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1257 AM EDT SUN APR 14 2013
AT KIWD...EXPECT VFR CONDITIONS TO PREVAIL THRU MID AFTN THOUGH
THERE MIGHT BE A PERIOD OF MVFR CIGS FOR THE NEXT COUPLE OF HRS PER
SATELLITE IMAGERY. AT KCMX/KSAW...MVFR CIGS SHOULD SCATTER OUT LATE
IN THE NIGHT AS LOW-LEVEL FLOW BECOMES MORE DIFFLUENT. VFR
CONDITIONS WILL THEN PREVAIL THRU THE AFTN. VIGOROUS LOW PRES SYSTEM
APPROACHING THE UPPER LAKES LATE TODAY WILL BRING A SHIELD OF PCPN
INTO UPPER MI. COLUMN WILL BE COLD ENOUGH TO SUPPORT SNOW AT THE
ONSET. SNOW SHOULD BEGIN AT KIWD AROUND 21Z AND AT KCMX/KSAW 1-3HRS
LATER. EXPECT A RAPID DROP TO IFR CONDITIONS AS SNOW BEGINS. AS NOSE
OF WARMER AIR ALOFT SURGES N...PCPN WILL LIKELY MIX WITH/CHANGE TO
SLEET/RAIN AT KIWD/KSAW IN THE EVENING. AS WARMING CONTINUES MORE
STRONGLY INTO CNTRL UPPER MI...PCPN WILL CHANGE TO JUST RAIN AT KSAW
BY LATE EVENING. AT KCMX...COLUMN WILL REMAIN COLDER LONGER...AND
ONLY EXPECT SLEET TO MIX WITH THE SNOW BY LATE EVENING. WITH E TO SE
UPSLOPE WINDS AT KCMX/KSAW...CONDITIONS SHOULD FALL TO LIFR IN THE
EVENING.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 415 PM EDT SAT APR 13 2013
NW WINDS UP TO 20-25 KTS OVER THE E HALF THIS EVENING WILL BECOME
LIGHT INTO SUN MORNING WITH ARRIVAL/PASSAGE OF HI PRES RIDGE AXIS.
AS THE NEXT LO PRES SYSTEM MOVES FROM THE NORTHERN PLAINS ON SUN
THRU MN SUN NIGHT AND THE PRES GRADIENT TIGHTENS...A STRONGER E WIND
VEERING SE UP TO 30 KTS WILL DEVELOP. OPTED TO ISSUE A GALE WATCH
FOR THE FAR W AND PORTIONS OF THE NCENTRAL AND E FOR LATE SUN/SUN
NIGHT WHERE THE EXPECTED FLOW IS ENHANCED BY TERRAIN INFLUENCES.
AS THE LOW PRESSURE SYSTEM MOVES FROM NORTHERN MN MONDAY MORNING TO
JAMES BY BY TUESDAY MORNING...STRONG SOUTHWEST WINDS MAY GUST TO 35
KNOTS OVER THE WESTERN HALF OF LAKE SUPERIOR MONDAY INTO MONDAY
NIGHT. WINDS THEN DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING
OUT OF THE N WEDNESDAY NIGHT INTO FRIDAY WHEN GALES MAY BE POSSIBLE.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM THIS EVENING THROUGH LATE TONIGHT FOR LSZ264-266.
GALE WARNING FROM 5 PM EDT /4 PM CDT/ THIS AFTERNOON TO 2 AM EDT
/1 AM CDT/ MONDAY FOR LSZ162.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...TITUS
AVIATION...ROLFSON
MARINE...KC/TITUS
AREA FORECAST DISCUSSION
NWS DULUTH MN
308 PM CDT SUN APR 14 2013
.SHORT TERM.../NOW - MONDAY/
THE FOCUS REMAINS THE WINTRY STORM SYSTEM THAT IS BEGINNING TO
MOVE INTO THE SOUTHERN FORECAST AREA. OVERALL...THIS SYSTEM HAS
BEEN DIFFICULT TO FORECAST FOR DUE TO DELAYS IN WHICH THE PCPN
FORMS AND MOVES INTO THE FORECAST AREA...CONSIDERABLE MODEL
DIFFERENCES IN SNOWFALL AMOUNTS...AND PCPN TYPE ISSUES FOR
NW WISCONSIN AND EAST CENTRAL MINNESOTA. THROUGH THE COURSE OF
THIS SHIFT...I HAVE ATTEMPTED TO DELAY THE ONSET OF THE PCPN AND
COMMUNICATE THE DELAY VIA THE GRAPHIC WEATHER STORY AND ON
FACEBOOK. THE MODELS SUGGEST THAT THE PCPN WILL INCREASE IN ITS
NORTHWARD SPEED LATER THIS AFTERNOON...SO I THINK WE MAY HAVE
FINALLY GOTTEN CLOSER TO BETTER DETERMINING TIMING. I EXTENDED
SOME ADVISORIES INTO EARLY THIS EVENING BASED ON THE PCPN DELAY
AND TO ALLOW THE EVENING SHIFT FORECASTER TIME TO SEE HOW THINGS
PAN OUT. I ALSO NOW THINK SOME AREAS OF NORTHERN MINNESOTA COULD
GET ANOTHER INCH OR TWO OF MORE SNOW THAN PREVIOUSLY
THOUGHT...SUCH AS ALONG THE NORTH SHORE.
THROUGH TONIGHT...A POTENT MID/UPPER LEVEL LOW IN THE NORTHERN
HIGH PLAINS AND ITS ASSOCIATED SURFACE LOW IN THE CENTRAL PLAINS
(EASTERN NEBRASKA AND WESTERN IOWA) WILL LIFT INTO MINNESOTA
TONIGHT. THE PCPN EXPECTED WITH THIS SYSTEM IS MOVING NORTHWARD
FROM EAST CENTRAL MINNESOTA AND WEST CENTRAL WISCONSIN AND ALREADY
BEGINNING TO MOVE INTO NORTHEAST MINNESOTA AND NORTHWEST
WISCONSIN. THE PCPN IS EXPECTED TO SPREAD ACROSS THE REST OF THE
NORTHEAST MINNESOTA AND NORTHWEST WISCONSIN THROUGH THE REST OF
THE AFTERNOON AND INTO THIS EVENING. THE MODELS SUGGEST THE
INITIAL BAND OF PCPN WILL COME DOWN AS SNOW AND MAY COME DOWN
QUITE FAST...WITH LIKELY SNOW RATES OF UP TO 1 TO 2 INCHES PER
HOUR IF NOT MORE. RECENT HRRR MODEL RUNS HAVE SHOWN SOME PERIODS
LATER THIS AFTERNOON OF 2 TO 3 INCHES PER HOUR. THERE IS STRONG
FRONTOGENESIS WITH THIS INITIAL BAND...SO IT IS CERTAINLY
POSSIBLE. CONSIDERING THE RELATIVELY WARM TEMPERATURES ACROSS THE
FORECAST AREA...MID 30S TO LOW 40S...THE PCPN MAY BRIEFLY BEGIN AS
A LIGHT RAIN BEFORE SWITCHING OVER TO SNOW ONCE THE RATES INCREASE
AND THE COLUMN COOLS. THERE WILL ALSO LIKELY BE A TRANSITION TO
SLEET AND RAIN ACROSS MUCH OF NORTHWEST WISCONSIN LATE THIS
AFTERNOON AND THIS EVENING. MUCH OF NORTHEAST MINNESOTA SHOULD GET
ABOUT 4 TO 9 INCHES OF SNOW...WITH THE GREATEST TOTALS ACROSS FAR
NORTHERN MINNESOTA. SOME AREAS MAY GET UP TO 10 INCHES...SUCH AS
ALONG THE NORTH SHORE OF LAKE SUPERIOR. I EXPECT LESS AMOUNTS OF
SNOW ACROSS NORTHWEST WISCONSIN AND EAST CENTRAL MINNESOTA BECAUSE
OF THE SLEET AND RAIN. HOWEVER...I WOULD NOT BE SURPRISED IF SOME
AREAS SEE CONSIDERABLE ACCUMULATION OF SLEET...WHICH IS WHY I
INCLUDED THE ACCUMULATION IN THE SNOW TOTALS I PROVIDED IN THE
WINTER WEATHER ADVISORIES FOR NORTHWEST WISCONSIN. STRONG EAST
WINDS ARE DEVELOPING ACROSS THE FORECAST AREA THIS AFTERNOON...AND
THEY SHOULD CONTINUE TO STRENGTHEN INTO THIS EVENING. THE WINDS
WILL BE STRONGEST NEAR LAKE SUPERIOR...ESPECIALLY NEAR THE TWIN
PORTS. THE 15 TO 30 MPH WINDS WITH GUSTS UP TO 40 MPH NEAR LAKE
SUPERIOR COULD REALLY REDUCE VISIBILITY DURING THE HEAVIER SNOW
BANDS AND CAUSE BRIEF NEAR WHITE-OUT CONDITIONS.
MONDAY...THE SNOW WILL LIKELY CONTINUE ACROSS MOST OF THE FORECAST
AREA THROUGH AT LEAST THE EARLY AFTERNOON AS THE LOW LIFTS INTO
ONTARIO. UP TO ADDITIONAL 1 TO 3 INCHES OF SNOW COULD FALL ACROSS
THE NORTHERN FORECAST AREA DURING THE DAY. THE WINTER STORM
WARNING FOR THE NORTHERN FORECAST AREA RUNS THROUGH 15Z TOMORROW
MORNING...BUT WE MIGHT NEED TO EXTEND THE WARNING INTO SUNDAY
AFTERNOON IF THE SNOW AND REDUCED VISIBILITY ARE STILL LINGERING.
GUSTY SOUTH TO SOUTHWEST WINDS WILL DEVELOP IN THE WAKE OF THE
PASSING LOW PRESSURE SYSTEM. TEMPERATURES SHOULD BE IN THE UPPER
30S TO LOW 40S.
.LONG TERM.../MONDAY NIGHT - SATURDAY/
THE UPPER LOW WILL BE OVER THE NORTHERN MINNESOTA/NORTHERN LAKE
SUPERIOR AREA 00Z TUESDAY THEN CONTINUE E/NE MONDAY NIGHT. A BAGGY
UPPER TROUGH...WITH AN EXTENSION TO THE SURFACE WILL REMAIN OVER
THE CWA INTO MONDAY NIGHT. WE KEPT A CHANCE FOR SNOW OVER MUCH OF
OUR NORTHEAST MINNESOTA ZONES MONDAY NIGHT...WITH THE BEST CHANCE
OVER THE BORDER REGION.
AN UPPER RIDGE WILL BUILD OVER THE REGION BRIEFLY TUESDAY...WITH
MOST AREAS DRY INTO TUESDAY NIGHT.
A DEEP TROUGH WILL THEN MOVE OVER THE ROCKIES TUESDAY
NIGHT...MOVING SLOWLY EAST THROUGH THE WEEK AFFECTING THE
NORTHLAND. ANOTHER SPRING STORM IS POISED TO AFFECT THE NORTHLAND
WEDNESDAY INTO AT LEAST THURSDAY...POSSIBLY LINGERING A BIT
LONGER. BOTH THE GFS AND ECMWF ARE IN GENERAL AGREEMENT WITH THE
TRACK OF THE SURFACE LOW...TAKING IT FROM THE TEXAS PANHANDLE AT
12Z WEDNESDAY TO LAKE MICHIGAN/SOUTHEAST WISCONSIN BY 12Z
THURSDAY...THEN IT CONTINUES NORTHEAST. AS IS THE CASE WITH THESE
SPRING STORMS...THE THERMAL PROFILES WILL BE CRITICAL TO PRECIP
TYPE. IT DOES APPEAR TEMPERATURES WILL BE WARM ENOUGH FOR A MIX
OVER AT LEAST NORTHWEST WISCONSIN. WE HAVE A RAIN/SNOW MIX OVER
NORTHWEST WISCONSIN WEDNESDAY NIGHT/THURSDAY...AND WILL LIKELY
NEED TO ADJUST THAT AS THIS SYSTEM NEARS. THE THREAT FOR MORE
ACCUMULATING SNOW IS INCREASING OVER NORTHEAST MINNESOTA INTO FAR
NORTHWEST WISCONSIN WEDNESDAY INTO THURSDAY. IT`S VERY DIFFICULT
TO TRY AND PLACE A NUMBER ON SNOW ACCUMULATION AT THIS POINT WITH
SO MUCH UNCERTAINTY REVOLVING THE PRECIP TYPE...BUT AT LEAST
SEVERAL INCHES OF SNOW WILL FALL OVER EASTERN MINNESOTA/FAR
NORTHWEST WISCONSIN FROM THIS SYSTEM. THE FORECAST MID-LATE WEEK
IS WORTH MONITORING CLOSELY AS THE PROBABILITY IT WILL HAVE A
SIGNIFICANT IMPACT ON THE NORTHLAND/S WEATHER IS INCREASING. MORE
DETAIL REGARDING PRECIP TYPE/AMOUNTS WILL BE ADDED AS WE PROGRESS
INTO THE EARLY PART OF THE WEEK.
AS THE UPPER TROUGH PASSES LATE IN THE WEEK...A SURFACE HIGH WILL
MOVE OVER THE AREA DRYING THINGS OUT FOR A TIME LATE IN THE
WEEK/EARLY WEEKEND. ANOTHER SHORTWAVE WILL BRING ANOTHER CHANCE
FOR MIXED PRECIP SATURDAY NIGHT/SUNDAY BUT THIS SYSTEM DOES NOT
LOOK TO BE PARTICULARLY STRONG.
TEMPERATURES THROUGH MOST OF THE PERIOD WILL REMAIN BELOW NORMAL.
&&
.AVIATION.../18Z TAFS/
AREA RADARS SHOWED PRECIPITATION WAS MOVING NORTH THROUGH
MINNESOTA/WISCONSIN...AND WAS BECOMING MORE WIDESPREAD. THE NAM
HAS A PRETTY GOOD HANDLE ON THIS...AS DO THE HIGH RES MODELS. WE
EXPECT THE PRECIPITATION TO BEGIN AS SNOW ALL AREAS...THEN IT MAY
BECOME A WINTRY MIX AT KHYR...AND POSSIBLY AT KBRD BRIEFLY. TIMING
IN THE TAFS MAY NEED TO BE ADJUSTED BY AN HOUR OR SO...AND WE`LL
DO THAT AS CONFIDENCE INCREASES FOR AN EXACT STARTING TIME.
VSBYS WILL DROP TO IFR OR LIFR WITHIN AN HOUR OF PRECIP
ONSET...AND AREAS AROUND LAKE SUPERIOR WILL SEE WINDY CONDITIONS
FURTHER REDUCING THE VSBY IN BLOWING SNOW. A DRY SLOT WILL WORK
NORTH LATER THIS EVENING/TONIGHT AND CAUSE THE PRECIP TO DIMINISH
OVER MOST OF THE TAFS. FORECAST SOUNDINGS SHOW TOP DOWN
DRYING...SO SOME SPOTTY DRIZZLE OR FREEZING DRIZZLE IS NOT OUT OF
THE QUESTION. WE DID NOT ADD THAT TO THE TAFS AT THIS TIME...AS
THAT IS MORE OF A SHORT TERM FORECAST ISSUE AND CAN BE ADDRESSED
WITH LATER UPDATES.
WINDS WILL SWITCH FROM EASTERLY TO SOUTHERLY LAT TONIGHT/MONDAY
MORNING...THEN BECOME SOUTHWEST.
&&
.POINT TEMPS/POPS...
DLH 28 38 30 38 / 100 70 20 10
INL 28 38 26 36 / 100 90 50 20
BRD 29 39 29 38 / 90 70 10 10
HYR 32 41 30 42 / 100 40 10 10
ASX 31 42 31 41 / 100 40 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 AM CDT MONDAY FOR MNZ025-026-
033>035-037.
WINTER WEATHER ADVISORY UNTIL 1 AM CDT MONDAY FOR MNZ036-038.
WINTER STORM WARNING UNTIL 10 AM CDT MONDAY FOR MNZ010>012-
018>021.
WI...WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR WIZ003-
004-006>009.
WINTER WEATHER ADVISORY UNTIL 7 AM CDT MONDAY FOR WIZ001-002.
LS...GALE WARNING UNTIL 3 AM CDT MONDAY FOR LSZ121-140>148.
&&
$$
SHORT TERM...GROCHOCINSKI
LONG TERM....MELDE
AVIATION...MELDE
AREA FORECAST DISCUSSION
NWS JACKSON MS
245 PM CDT SUN APR 14 2013
.SHORT TERM...TONIGHT THROUGH EARLY WEDNESDAY...
THE PRIMARY CONCERNS IS THE DENSE FOG POTENTIAL FOR
TONIGHT...AREAS OF FOG FOR LATE MONDAY NIGHT INTO EARLY
TUESDAY...FOLLOWED BY THE LAST OF THE ISOLATED CONVECTION LEAVING THE REGION
BY THIS EVENING. THE LAST CONCERNS ARE PATCHY FOG WEDNESDAY MORNING
AND POPS AND TEMPS.
LATEST SATELLITE IMAGERY SHOWED A SHORTWAVE TROUGH MOVING EAST OVER
THE ARKLAMISS TO THE NORTHERN GULF OF MEXICO. THE SURFACE FRONT WAS
SOUTH OF THE REGION. THE BEST UPPER DIVERGENCE HAS MOVED EAST OF THE
REGION ALONG WITH STRONG MOISTURE TRANSPORT...WHICH TIES WITH THE
RAINS MOVING EAST OF THE FORECAST AREA. HRRR AND LOCAL WRF STILL
SHOWS SOME POTENTIAL FOR SOME ISOLATED CONVECTIVE DEVELOPMENT FOR
THIS AFTERNOON BEFORE EXITING BY THIS EVENING. SO HAVE ISOLATED POPS
FROM WEST TO EAST FOR THE PREFIRST PERIOD. THE PRESSURE GRADIENT
HAS RELAXED IN THE EAST AS BREEZY CONDITIONS HAVE DECREASED IN THE
EAST.
FOR TONIGHT AND MONDAY...THE RAINS WILL HAVE EXITED THE REGION...BUT
WITH THE DAMP GROUND...LIGHT WINDS...AND FAIR SKIES. DENSE FOG WILL BE
LIKELY. THIS WAS SHOWN BY SREF PROBS OF 90-100 PERCENT...MODEL
SOUNDINGS AND MODEL CROSS SECTIONS. EXPECT AREAS OF DENSE FOG TO
DEVELOP AFTER MIDNIGHT. THIS WILL PROBABLY PROMPT THE NEED FOR A
DENSE FOG ADVISORY. WILL LET THE EVENING SHIFT DECIDE WHERE TO PUT
IT...IF THEY DECIDE TO DO IT. TRAVELERS SHOULD BE CAUTIOUS IN DENSE
FOG AREAS. MEANWHILE A WEAK WARM FRONT WILL PUSH NORTH OVER THE
REGION DURING THE NIGHT HELPING THE FOG ALONG AS THE REGION WILL BE
UNDER A FLAT UPPER RIDGING. LOWS TONIGHT WILL RANGE FROM THE MIDDLE
50S NORTHEAST TO THE LOWER 60S SOUTH. WENT CLOSE TO MAV GUIDANCE. AS
WE GO INTO MONDAY MORNING THE AREAS OF DENSE FOG SHOULD LIFT BY MID
MORNING. THE UPPER RIDGE WILL AMPLIFY EAST OF THE REGION PUTTING US
UNDER SOUTHWEST FLOW ALOFT. THIS WILL ALLOW WARM ADVECTION IN THE
LOW LEVELS FOR ABOVE NORMAL HIGH TEMPERATURES. AFTERNOON HIGHS WILL
RANGE FROM THE LOWER TO MIDDLE 80S. WENT CLOSE TO MAV GUIDANCE.
FOR MONDAY NIGHT AND TUESDAY...ONCE AGAIN CONDITIONS WILL FAVOR
ANOTHER ROUND OF FOG. SREF PROBS WILL BE HIGH. MODEL CROSS SECTIONS
AND AREAS MODEL SOUNDING FAVOR THOSE CONDITIONS. SO HAVE PUT IN
AREAS OF FOG FOR MONDAY NIGHT INTO MID MORNING TUESDAY. MEANWHILE AN UPPER
TROUGH WILL BE EVOLVING OVER THE WESTERN US...WHICH WILL BE OUR
STORM SYSTEM FOR THURSDAY. LOWS WILL BE MAINLY IN THE 60S. FOR TUESDAY
SOME GUIDANCE TRIES TO SQUEEZE OUT SOME LOW POPS DURING THE DAY. BUT
MODEL SOUNDINGS LOOK RATHER CAPPED FOR THE DAY. IT MAY BE ABLE TO
SQUEEZE OUT SOME HIT OR MISS LIGHT SPOTTY SHOWERS IF IT CAN GET BY
THE CAP. BUT IM MORE FOR KEEPING IT DRY FOR THE DAY. HIGHS ONCE
AGAIN WILL BE ABOVE NORMAL WITH READINGS IN THE LOWER TO MIDDLE 80S.
FOR TUESDAY NIGHT INTO EARLY WEDNESDAY...ONCE AGAIN MODEL PROGS
FAVOR FOR SOME KIND OF FOG DEVELOPMENT. USUALLY DO NOT PUT IN FOG
FOR THIS FAR OUT...BUT SREF PROBS ARE PAINTING AROUND 60 TO 85
PERCENT. SO PUT IN PATCHY FOG FOR LATE TUESDAY NIGHT UNTIL MID WEDNESDAY
MORNING. MEANWHILE THE UPPER TROUGH WILL BE EVOLVING OVER THE
ROCKIES. LOWS FOR TUESDAY NIGHT WILL BE IN THE 60S. WENT CLOSE TO A
BLEND OF GMOS AND MAV GUIDANCE./17/
.LONG TERM...WEDNESDAY THROUGH SUNDAY...
NOT MUCH CHANGE IN THE EXTENDED PORTION OF THE FORECAST. RATHER
STOUT SUBTROPICAL RIDGING WILL BE IN PLACE OVER THE SOUTHEASTERN
CONUS WEDNESDAY IN ADVANCE OF A DEEP TROUGH TAKING SHAPE OVER
THE WESTERN HALF OF THE COUNTRY. STRONG SURFACE HIGH PRESSURE OVER
THE SOUTHEAST WILL CONTINUE TO PULL WARM/MOIST GULF AIR ACROSS THE
ARKLAMISS THROUGH EARLY THURSDAY BEFORE A COLD FRONT ASSOCIATED WITH
THE AFOREMENTIONED LOW PRESSURE SYSTEM SWINGS ACROSS THE REGION.
TEMPERATURES TUE/WED ARE GOING TO BE WELL ABOVE NORMAL FOR MID APRIL
WITH HIGHS CLIMBING INTO THE MID 80S.
THINGS WILL CHANGE HEADED INTO THURSDAY AS THE COLD FRONT APPROACHES
THE REGION. CLOUD COVER WILL HELP KEEP TEMPS A TAD COOLER ALTHOUGH
HIGHS IN THE UPPER 70S/LOWERS 80S ARE STILL EXPECTED (WARMEST ACROSS
THE EAST). THE MODELS CONTINUE TO DANCE AROUND WITH FRONTAL TIMING
BUT REMAIN FOCUSED IN THE THURSDAY AFTERNOON/THURSDAY EVENING
TIMEFRAME. THE ANTECEDENT WARM/MOIST ATMOSPHERE THAT WILL BE IN
PLACE AHEAD OF THE FRONT SHOULD SET THE STAGE FOR SEVERE WEATHER
POTENTIAL AS THE FRONT PASSES...BUT EXACT DETAILS WITH RESPECT TO
COVERAGE/INTENSITY REMAIN UNCERTAIN THIS FAR IN ADVANCE. SURFACE DEW
POINTS LOOK TO BE IN THE UPPER 60S/NEAR 70 BY THURSDAY AFTERNOON...
AND COUPLED WITH STEEP MID LEVEL LAPSE RATES SHOULD BE SUFFICIENT
FOR SBCAPE VALUES NEAR/IN EXCESS OF 1500J/KG ACROSS AREAS AHEAD OF
THE FRONT. BEST HEIGHT FALLS/SHEAR LOOKS LIKE IT MAY BE CONFINED
ACROSS AREAS FURTHER NORTH THAN SOUTH...BUT WON`T TRY TO GET TOO
SPECIFIC AT THIS POINT. WILL KEEP A MENTION OF SEVERE WEATHER
POTENTIAL IN THE HWO/GRAPHICS FOR THU AFTN/EVE.
UPDATE...THE 12Z RUNS OF THE GFS AND EURO STILL FAVOR THURSDAY TIME
FRAME FOR SEVERE WEATHER CHANCES.
MUCH COOLER WEATHER CAN BE EXPECTED IN WAKE OF THE FRONT AS A 1025MB
HIGH PRESSURE CENTER BUILDS OVER THE MS VALLEY. TEMPS WILL LIKELY
FALL BACK BELOW NORMAL FRI THROUGH THE WEEKEND...ALONG WITH CLEAR
SKIES. AS FOR TEMPS/POPS...I DID CONTINUE THE TREND OF TRIMMING AFTN
POPS TUESDAY AS A STRONG CAP ACROSS THE REGION KEEPS THINGS IN CHECK.
WITH THAT SAID...WOULDN`T BE TOTALLY SURPRISED TO SEE A SHOWER OR
THUNDERSTORM EACH AFTN/NOTHING SIGNIFICANT. TEMPS LOOKED GOOD UNTIL
THE FRONT PASSES WHERE COOLER HIGHS/LOWS OFFERED BY THE EURO MOS FOR
THE WEEKEND SEEMED A BIT MORE REASONABLE. /BK/17/
&&
.AVIATION...AREAS OF MVFR CIGS WILL CONTINUE THIS AFTERNOON INTO THE
EVENING HOURS. CONDITIONS WILL DETERIORATE TONIGHT WITH WIDESPREAD
IFR/LIFR CIGS/VSBYS DEVELOPING BY MIDNIGHT WHEN FOG/LOW STRATUS
FORMATION IS EXPECTED. IFR/LIFR FOG/STRATUS WILL MIX OUT MID MONDAY
MORNING...LEAVING MVFR TO VFR CIGS FOR MONDAY AFTERNOON./03/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 60 84 68 85 / 4 5 10 14
MERIDIAN 59 84 67 84 / 4 5 10 14
VICKSBURG 60 85 66 85 / 5 6 11 14
HATTIESBURG 60 85 66 85 / 4 8 11 14
NATCHEZ 61 84 68 84 / 3 8 10 14
GREENVILLE 61 83 66 85 / 6 10 12 14
GREENWOOD 61 84 67 84 / 4 5 12 14
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
17/03/BK
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1205 PM CDT SUN APR 14 2013
.UPDATE...LATEST SATELLITE IMAGERY SHOWED A SHORTWAVE TROUGH MOVING
EAST OVER THE ARKLAMISS TO THE NORTHERN GULF OF MEXICO. THE SURFACE
FRONT WAS OFFSHORE. THE BEST UPPER DIVERGENCE HAS MOVED EAST OF THE REGION
ALONG WITH STRONG MOISTURE TRANSPORT...WHICH TIES WITH THE RAINS
MOVING EAST OF THE FORECAST AREA. HRRR AND LOCAL WRF STILL SHOWS SOME POTENTIAL
FOR SOME CONVECTIVE DEVELOPMENT FOR THIS AFTERNOON BEFORE EXITING BY THIS
EVENING. SO HAVE LAID OUT ISOLATED TO SCATTERED POPS FROM WEST TO
EAST. THE PRESSURE GRADIENT CONTINUES TO BE TIGHT FOR SOME PERIODIC
BREEZY CONDITIONS OF 30 TO 40 MPH FOR THIS AFTERNOON. CURRENT
FORECAST HIGHS ARE STILL ON TRACK AS SUNLIGHT FILTERS INTO THE
REGION./17/
./PREVIOUS DISCUSSION...440 AM CDT SUN APR 14 2013
.DISCUSSION...
TONIGHT THROUGH MONDAY NIGHT...
AS WE GO INTO TONIGHT...SKIES WILL ATTEMPT TO CLEAR OVER A MOIST
BOUNDARY LAYER AND RAIN-SOAKED GROUND...AND THIS SHOULD RESULT IN
AREAS OF FOG FOR LATE TONIGHT THROUGH EARLY MONDAY. AFTER A WARM AND
DRY MONDAY...A REPEAT OF STRATUS/FOG WILL BE POSSIBLE MONDAY NIGHT.
/EC/
TUESDAY THROUGH SUNDAY...
NOT MUCH CHANGE IN THE EXTENDED PORTION OF THE FORECAST. RATHER
STOUT SUBTROPICAL RIDGING WILL BE IN PLACE OVER THE SOUTHEASTERN
CONUS TUESDAY AND WEDNESDAY IN ADVANCE OF A DEEP TROUGH TAKING SHAPE
OVER THE WESTERN HALF OF THE COUNTRY. STRONG SURFACE HIGH PRESSURE
OVER THE SOUTHEAST WILL CONTINUE TO PULL WARM/MOIST GULF AIR ACROSS
THE ARKLAMISS THROUGH EARLY THURSDAY BEFORE A COLD FRONT ASSOCIATED
WITH THE AFOREMENTIONED LOW PRESSURE SYSTEM SWINGS ACROSS THE REGION.
TEMPERATURES TUE/WED ARE GOING TO BE WELL ABOVE NORMAL FOR MID APRIL
WITH HIGHS CLIMBING INTO THE MID 80S.
THINGS WILL CHANGE HEADED INTO THURSDAY AS THE COLD FRONT APPROACHES
THE REGION. CLOUD COVER WILL HELP KEEP TEMPS A TAD COOLER ALTHOUGH
HIGHS IN THE UPPER 70S/LOWERS 80S ARE STILL EXPECTED (WARMEST ACROSS
THE EAST). THE MODELS CONTINUE TO DANCE AROUND WITH FRONTAL TIMING
BUT REMAIN FOCUSED IN THE THURSDAY AFTERNOON/THURSDAY EVENING
TIMEFRAME. THE ANTECEDENT WARM/MOIST ATMOSPHERE THAT WILL BE IN
PLACE AHEAD OF THE FRONT SHOULD SET THE STAGE FOR SEVERE WEATHER
POTENTIAL AS THE FRONT PASSES...BUT EXACT DETAILS WITH RESPECT TO
COVERAGE/INTENSITY REMAIN UNCERTAIN THIS FAR IN ADVANCE. SURFACE DEW
POINTS LOOK TO BE IN THE UPPER 60S/NEAR 70 BY THURSDAY AFTERNOON...
AND COUPLED WITH STEEP MID LEVEL LAPSE RATES SHOULD BE SUFFICIENT
FOR SBCAPE VALUES NEAR/IN EXCESS OF 1500J/KG ACROSS AREAS AHEAD OF
THE FRONT. BEST HEIGHT FALLS/SHEAR LOOKS LIKE IT MAY BE CONFINED
ACROSS AREAS FURTHER NORTH THAN SOUTH...BUT WON`T TRY TO GET TOO
SPECIFIC AT THIS POINT. WILL KEEP A MENTION OF SEVERE WEATHER
POTENTIAL IN THE HWO/GRAPHICS FOR THU AFTN/EVE.
MUCH COOLER WEATHER CAN BE EXPECTED IN WAKE OF THE FRONT AS A 1025MB
HIGH PRESSURE CENTER BUILDS OVER THE MS VALLEY. TEMPS WILL LIKELY
FALL BACK BELOW NORMAL FRI THROUGH THE WEEKEND...ALONG WITH CLEAR
SKIES. AS FOR TEMPS/POPS...I DID CONTINUE THE TREND OF TRIMMING AFTN
POPS TUE/WED AS A STRONG CAP ACROSS THE REGION KEEPS THINGS IN
CHECK. WITH THAT SAID...WOULDN`T BE TOTALLY SURPRISED TO SEE A
SHOWER OR THUNDERSTORM EACH AFTN/NOTHING SIGNIFICANT. TEMPS LOOKED
GOOD UNTIL THE FRONT PASSES WHERE COOLER HIGHS/LOWS OFFERED BY THE
EURO MOS FOR THE WEEKEND SEEMED A BIT MORE REASONABLE. /BK/
&&
.AVIATION...WIDESPREAD RAIN...ALONG WITH A FEW THUNDERSTORMS...WILL
CONTINUE ALONG AND EAST OF THE NATCHEZ TRACE CORRIDOR THIS
MORNING...GRADUALLY DIMINISHING FROM THE WEST THROUGH THE EARLY
AFTERNOON. PERIODS OF GUSTY WIND ARE EXPECTED IMMEDIATELY BEHIND THE
HEAVIER RAIN SHIELD. SUSTAINED WIND SPEEDS 20-30 MPH WITH POSSIBLE
GUSTS AROUND 40 MPH WILL DEVELOP AS RAIN DIMINISHES AND CONTINUE 2-3
HOURS BEFORE WIND SPEEDS DECREASE TO 5-15 MPH. CONDITIONS WILL BE
MOSTLY VFR BUT AREAS OF MVFR CIGS/VSBYS CAN BE EXPECTED IN REGIONS
OF HEAVIER RAIN. WIDESPREAD LIFR CONDITIONS MAY DEVELOP LATE TONIGHT
AFTER RAIN HAS ENDED WHEN FOG/LOW STRATUS FORMATION IS EXPECTED. ANY
FOG/STRATUS WILL MIX OUT MID/LATE MONDAY MORNING.
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 74 63 85 68 / 20 7 5 11
MERIDIAN 70 58 82 65 / 29 10 5 11
VICKSBURG 75 61 85 67 / 17 5 6 11
HATTIESBURG 77 63 86 69 / 29 7 8 7
NATCHEZ 76 62 84 70 / 17 4 8 7
GREENVILLE 75 61 83 67 / 16 6 10 12
GREENWOOD 75 62 83 68 / 16 6 5 12
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
17/03/EC/BK
AREA FORECAST DISCUSSION
NWS BILLINGS MT
946 AM MDT SUN APR 14 2013
.UPDATE...
DYNAMIC UPPER TROUGH CONTINUING TO IMPACT SOUTHEAST MONTANA THIS
MORNING WITH AREAS OF HEAVY SNOW. SNOW AMOUNTS HAVE VARIED FROM 3
TO 6 INCHES OVER THE FAR EASTERN ZONES. DRY SLOT HAS MOVED INTO
CARTER COUNTY THIS MORNING BUT WRAP AROUND FROM THE LOW PRESSURE
SYSTEM WILL BRING SNOW BACK INTO THE AREA BY LATE MORNING. CURRENT
HIGHLIGHTS ARE WORKING WELL AND WILL MAKE NO ADJUSTMENTS.
FOR UPDATES THIS MORNING...HAVE INCREASED POPS FOR LIVINGSTON AS
ENERGY SLIDING DOWN THE BACKSIDE OF THE UPPER TROUGH IS BRINGING
LIGHT SNOW. THIS LIGHT SNOW IS EXPECTED TO CONTINUE INTO EARLY
AFTERNOON. BAND OF SNOW HAS SET UP JUST EAST OF BILLINGS AND WAS
SLOWLY SHIFTING TO THE WEST TOWARD BILLINGS. RAP MODELS IS
HANDLING THIS WELL AND IS DEPICTING A BAND OF FRONTOGENESIS TO SET
UP FROM ROUNDUP SOUTHEAST THROUGH BILLINGS TO FORT SMITH. THE RAP
MODEL IS GENERATING SOME GOOD QPF VALUES AND HAVE GONE AHEAD AND
RAISED POPS TO CATEGORICAL FOR THIS AFTERNOON. WINDS ALONG THE
BAND OF LIFT WILL SHIFT TO THE NORTHEAST BRINGING WEAK UPSLOPE
FLOW AND HAVE ADDED 1 TO 2 INCHES OF SNOW ALONG THIS BOUNDARY.
ALSO LOWERED TEMPERATURES FOR BILLINGS THIS AFTERNOON AS COLD AIR
ADVECTS INTO THE AREA. RICHMOND
&&
.SHORT TERM...VALID FOR TDY AND MON...
MODELS HAVE FINALLY COME IN LINE WITH THE SYSTEM IMPACTING THE
FORECAST AREA AND THE GFS HAS APPARENTLY WON OUT. THE NAM HAS
DRAMATICALLY SHIFTED SOUTH WITH THE UPPER LOW POSITION FOR EARLY
TODAY AND COME TO A VIRTUAL AGREEMENT WITH THE GFS OF A COUPLE OF
DAYS AGO. SAME IS TRUE OF THE ECMWF. A SECONDARY UPPER LOW WAS
FORMING WITHIN THE DEEP UPPER TROUGH OVER THE NORTHERN ROCKIES.
THE POSITION OF THIS UPPER LOW WAS OVER FAR SOUTHEAST MONTANA AND
PRESSING TOWARD NORTHWEST SOUTH DAKOTA.
A LARGE SWATH OF SNOWFALL WAS OVER SOUTHEAST MONTANA THIS
HOUR...BASICALLY EAST OF A HYSHAM TO BUSBY LINE. MODERATE TO HEAVY
SNOW HAS BEEN REPORTED IN MILES CITY AND BAKER OVER THE LAST
SEVERAL HOURS. THE HEAVIEST SNOWFALL DOES APPEAR TO BE SHIFTING
NORTHWARD INTO NORTHEAST MONTANA AT THE MOMENT. THE GFS WRAPS
COLDER AIR AND SNOW BACK INTO SOUTHEAST MONTANA TOWARD DAWN...SO
DO EXPECT SNOWFALL TO PICK BACK UP AGAIN. HIGHLIGHTS WILL REMAIN
IN PLACE AS THE SURFACE LOW WRAPS UP AND GENERATES STRENGTHENING
WINDS FOR BLOWING SNOW. AM CONCERNED WITH THE DRIER AIR WORKING
INTO NORTHEAST WYOMING AT THE MOMENT AS THE LOW WRAPS UP. THIS
DRIER AIR MAY BE A WRENCH IN THINGS AND DECREASE SNOW RATES TODAY
FOR THE SOUTHEAST. WILL HAVE TO WATCH THIS CLOSELY. FOR NOW
THOUGH...WILL KEEP HIGHLIGHTS RUNNING.
THE COLDER AIR WILL BACK INTO BILLINGS BY LATE MORNING OR EARLY
AFTERNOON. THIS SHOULD TURN WINDS TO THE NORTH AND NORTHEAST AND
INCREASE UPSLOPE GRADIENTS. UPSLOPE LIGHT SNOW SHOULD DEVELOP
TODAY AS THE COLDER AIR DRIVES IN. THE EAST SLOPES...FROM NYE TO
RED LODGE...SHOULD BE ABLE TO PICK UP A COUPLE INCHES OF UPSLOPE
SNOW TODAY AND EARLY THIS EVENING. WILL BE A CHILLY DAY AS HIGHS
WILL BE EARLY AND BILLINGS WILL STRUGGLE TO GET OUT OF THE 30S
WITH TEMPERATURES HOLDING STEADY OR SLOWLY FALLING THIS AFTERNOON
WITH COLD ADVECTION.
UPSLOPE WILL REMAIN IN PLACE TONIGHT AND MONDAY AS AN UPPER
TROUGH OFF THE PACIFIC NORTHWEST COAST DROPS INTO NORTHERN
CALIFORNIA AND INDUCES SURFACE PRESSURE FALLS. THIS WILL KEEP
THINGS CHILLY ON MONDAY WITH CLOUD COVER AND A CHANCE OF UPSLOPE
LIGHT SNOW. WILL KEEP POPS AT LEAST IN THE HIGH SCATTERED CATEGORY
FOR CENTRAL AND WESTERN ZONES. THE SYSTEM IMPACTING THE EAST WILL
PULL AWAY TONIGHT AND MONDAY AND ALLOW CONDITIONS TO IMPROVE. TWH
.LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT...
THE EXTENDED FORECAST CONTINUES TO APPEAR ON TRACK WITH UNSETTLED
WEATHER THROUGHOUT. TEMPS WILL BE WELL BELOW NORMAL TO START THE
PERIOD...WITH A GRADUAL WARM UP THROUGH THE WEEKEND. THERE IS
STILL MUCH UNCERTAINTY IN THE DETAILS WITH REGARD TO THE EVOLUTION
OF THE PATTERN AND HOW IT WILL IMPACT WEATHER ACROSS THE REGION.
IN GENERAL THE REGION IS DOMINATED BY A BROAD UPPER LEVEL TROF
THROUGHOUT THE EXTENDED PERIOD. THIS SHOULD KEEP SHALLOW COLD AIR
OVER THE AREA...UNTIL RIDGING OVER THE PACIFIC SHIFTS MORE
EASTWARD. THIS IS PROGGED TO BEGIN LATE NEXT WEEK AND CONTINUE TO
SHIFT SLOWLY EASTWARD THROUGH THE WEEKEND...AND AFFECTS A GRADUAL
WARMUP ACROSS THE REGION.
AS FOR PRECIP POTENTIAL...THE NEXT PACIFIC TROF SLIDES THROUGH THE
REGION ON TUESDAY...AND INTO WEDNESDAY. STRONGEST FORCING IS
CURRENTLY PROGGED TO REMAIN SOUTH OF THE REGION TUESDAY...BUT
SHOULD STILL SEE POTENTIAL FOR PRECIP ACROSS THE REGION...THOUGH
ACCUMULATIONS SHOULD BE ON THE LOW END. THE POTENTIAL WEDNESDAY
WILL BE A BIT BETTER...AS TROF IS PROGGED TO LIFT TO THE
NORTHEAST...BUT EXACT TRACK WILL MAKE BIG IMPACT AS TO WHERE
ACCUMULATING SNOWFALL WILL OCCUR. SO FURTHER ATTENTION WILL BE
REQUIRED ON LATER SHIFTS. SLOW PROGRESS OF THE WEATHER SYSTEMS
EASTWARD WILL KEEP THE REGION UNDER NORTHWEST FLOW ALOFT...THROUGH
THE REMAINDER OF THE PERIOD...WITH SEVERAL SHORTWAVES THROUGH THE
FLOW TO BRING CONTINUED SHOWER POTENTIAL ACROSS THE REGION THROUGH
NEXT WEEKEND. AAG
&&
.AVIATION...
SNOW ACROSS EASTERN MONTANA...INCLUDING KMLS AND KBHK...WILL
CONTINUE THROUGH THE DAY...RESULTING IN WIDESPREAD MVFR/IFR
CONDITIONS...AND LOCALIZED LIFR/VLIFR CONDITIONS. SNOW SHOWERS ARE
ALSO EXPECTED TO REDEVELOP TODAY ACROSS THE WESTERN
ROUTES...INCLUDING KBIL...KLVM...AND KSHR...RESULTING IN LOCALIZED
MVFR/IFR CONDITIONS IN LOWERED CIGS AND VIS. WINDS ARE ALSO
EXPECTED TO BECOME BRISK...RESULTING IN POTENTIAL FOR BLOWING SNOW
AND FURTHER REDUCED VIS. AAG
&&
.PRELIMINARY POINT TEMP/POPS...
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 038 023/037 022/036 021/041 024/051 031/054 034/056
9/J 55/S 35/S 33/S 21/B 23/W 33/W
LVM 037 018/036 018/034 018/040 019/049 028/052 032/055
7/J 55/S 54/S 32/S 22/W 23/W 33/W
HDN 036 023/038 021/036 018/041 022/051 028/055 032/057
9/J 65/O 35/S 34/S 21/B 24/W 44/W
MLS 032 022/036 020/034 019/037 021/046 027/052 030/053
+/S 75/S 34/S 23/S 11/E 23/W 22/W
4BQ 032 020/035 019/034 015/035 017/043 026/051 028/051
+/S 74/S 25/S 44/S 11/E 23/W 33/W
BHK 027 020/033 018/033 017/031 016/039 023/046 028/047
+/S 74/S 33/S 23/S 11/E 22/W 32/W
SHR 034 020/036 020/033 018/036 019/046 024/051 028/052
6/J 45/S 26/S 55/S 22/W 23/W 34/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL MIDNIGHT MDT TONIGHT
FOR ZONES 31-32-36-58.
WINTER STORM WARNING IN EFFECT UNTIL MIDNIGHT MDT TONIGHT FOR
ZONES 33-37.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
121 AM EDT SUN APR 14 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE OVER THE NORTHERN GREAT LAKES WILL BE THE
DOMINANT WEATHER FEATURE ACROSS THE NORTH COUNTRY THIS WEEKEND AS IT
SHIFTS EASTWARD ACROSS SOUTHERN ONTARIO AND QUEBEC. THE LOW WILL BE
ACCOMPANIED BY SCATTERED RAIN AND SNOW SHOWERS. HIGH PRESSURE AND
DRY CONDITIONS RETURN FOR MONDAY.TEMPERATURES WILL BE A BIT BELOW
NORMAL THROUGH SUNDAY...BUT THEN WARM TO ABOVE SEASONAL LEVELS
MONDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 1249 AM EDT SUNDAY...INHERITED FORECAST IN GOOD SHAPE WITH
ONLY AN INCREASE TO POPS AND WX NEEDED TO ACCOUNT FOR MORE
SCATTERED RAIN/SNOW SHOWERS OVERNIGHT AND SUNDAY. PREVIOUS
DISCUSSION FOLLOWS...
VIGOROUS MID-LEVEL VORT MAX EVIDENT ON WV IMAGERY NEAR LAKE
ONTARIO AT 2230Z WILL LIFT NEWD ACROSS OUR FORECAST AREA DURING
THE LATE EVENING HOURS. ASSOCIATED BANDS OF SHOWERS WILL ACCOMPANY
THIS FEATURE...AIDED BY SWLY UPSLOPE FLOW IN THE NRN ADIRONDACKS
WHERE QPF SHOULD BE THE GREATEST (BUT STILL ONLY 0.1-0.2").
FREEZING LEVELS INITIALLY AROUND 2000 FT PER RAP SOUNDINGS...BUT
SHOULD DROP TO NEAR 1000 FT DURING THE PRE-DAWN HOURS.
THUS...LOOKING FOR SCATTERED VALLEY RAIN SHOWERS GOING TO A
RAIN/SNOW SHOWER MIX AFTER MIDNIGHT. ALREADY SEEING -SHSN AT
SARANAC LAKE WHERE THE 23Z TEMP IS 35F. TEMPS SHOULD FALL BELOW
FREEZING ACROSS THE ADIRONDACKS AND N-CENTRAL/NERN VT ALLOWING FOR
A LIGHT SNOW ACCUMULATION OF A DUSTING TO 2" OVERNIGHT...HIGHEST
IN THE NRN ADIRONDACKS WHERE UPSLOPE FLOW WILL LOCALLY AID IN
FREQUENCY OF SNOW SHOWER ACTIVITY. SKIES WILL GENERALLY REMAIN
OVERCAST...THOUGH MODELS INDICATE SOME BINOVC POSSIBLE AROUND
04-06Z ONCE THE VORT MAX PASSES THROUGH. A SECOND UPR WAVE MOVING
IN FROM THE GREAT LAKES FROM 08-12Z SHOULD REESTABLISH OVERCAST
CONDITIONS LATE. GUSTY SW WINDS WILL CONTINUE FOR ANOTHER 1-3
HOURS ACROSS NRN NY (UP TO 30 MPH IN THE ST. LAWRENCE
VALLEY)...BEFORE GRADUALLY SUBSIDING. MIN TEMPS TONIGHT WILL BE
MOSTLY IN THE LOWER TO MID 30S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 355 PM EDT SATURDAY...AFOREMENTIONED UPPER LEVEL LOW
CONTINUES TO AFFECT THE NORTH COUNTRY SUNDAY AS IT SHIFTS EAST
THROUGH SOUTHERN QUEBEC. SEVERAL MORE PIECES OF SHORTWAVE ENERGY
ROUNDING THE BASE OF THE UPPER TROUGH AS IT DEPARTS WILL KEEP
CHANCES FOR RAIN/SNOW SHOWERS. FLOW TURNS FROM SOUTHWEST TO MORE
WEST AND NORTHWEST DURING SUNDAY...SO BETTER CHANCES FOR
PRECIPITATION WILL BE OVER THE HIGHER TERRAIN AND ACROSS THE
OROGRAPHICALLY FAVORED WESTERN SLOPES. TEMPS REMAIN NEAR NORMAL
WITH HIGHS SUNDAY IN THE MID 40S TO AROUND 50. UPPER TROUGH FINALLY
DEPARTS SUNDAY NIGHT AND UPPER LEVEL RIDGE BUILDS INTO THE
NORTHEAST BY MONDAY. ANY SCATTERED RAIN/SNOW SHOWERS WILL END SUNDAY
EVENING FOLLOWED BY CLEARING. ON MONDAY...EXPECT A MIX OF CLOUDS AND
SUNSHINE AND NOTICEABLY MILDER TEMPERATURES. MEAN 925 TEMPS RISE TO
+5-10C SUPPORTING HIGHS IN THE UPPER 50S AND LOWER 60S. WINDS WILL
ALSO BE ON THE INCREASE FROM THE SOUTH DURING THE DAY WITH SOME
GUSTS 25-30 MPH LIKELY DURING THE AFTERNOON...ESPECIALLY IN THE
CHAMPLAIN VALLEY. SOUTHERLY FLOW CONTINUES TO INCREASE MONDAY NIGHT
AS SURFACE HIGH MOVES FURTHER EAST AND PRESSURE GRADIENT TIGHTENS IN
ADVANCE OF APPROACHING FRONTAL SYSTEM. EXPECT AN INCREASE IN CLOUDS
WITH A CHANCE OF SHOWERS OVERNIGHT...MAINLY OVER NORTHERN TIER OF
ZONES. NON-DIURNAL TEMPERATURE TRENDS LIKELY ACROSS MUCH OF THE AREA
WHERE LOWS WILL BE MAINLY IN THE 40S...AND NOT MUCH BELOW 50 IN
SAINT LAWRENCE VALLEY. EXCEPTION WILL BE EAST OF THE GREEN WHERE
DECOUPLING EXPECTED...ALLOWING FOR LOWS IN THE 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 402 PM EDT SATURDAY...ACTIVE PATTERN DURING THE LONG TERM
WITH WARMER TEMPERATURES AND THREAT OF CONVECTION. GFS AND ECMWF
SHOWING GENERAL AGREEMENT WITH SOME TIMING DIFFERENCES.
HIGH PRESSURE SLIDES FURTHER INTO THE ATLANTIC AS COLD FRONT
PUSHES THROUGH THE NORTH COUNTRY TUESDAY INTO TUESDAY NIGHT.
PLENTY OF SOUTHERLY FLOW AHEAD OF THE FRONT...AT 10-20 KTS...WILL
FILTER IN WARM MOIST AIR. 1000-850MB TEMP LAPSE RATES WILL REACH
8+ C/KM ON TUESDAY...HAVE INCLUDED SLGT CHC TS. AS SFC TEMPS
REACHING LOW 60S IN THE VALLEYS AND MID 50S IN THE HIGH TRRN.
WINDS WILL SHIFT SW-W BEHIND THE FRONT WILL CLOUDS REMAINING OVER
NIGHT...KEEPING MIN TEMPS IN THE M30S-M40S.
GFS PUSHING THE FRONT THROUGH FASTER THAN ECMWF...EDGING IN HIGH
PRESSURE BY WEDNESDAY MORNING. GIVEN PROXIMITY OF UPPER LEVEL
VORTICITY...WILL KEEP CLOUDS OVER THE REGION. 925MB TEMPS OF 7C-
12C ON TUESDAY WILL COOL TO 4C-6C ON WEDNESDAY BEHIND THE FRONT
WITH DISSIPATING THREAT OF PRECIP EARLY WEDNESDAY. MAX TEMPS ON
WEDNESDAY COOLER...IN THE 50S.
OVERNIGHT WEDNESDAY NIGHT...THE COLD FRONT WILL BEGIN TO LIFT
BACK NORTH AS A WARM FRONT WITH ANOTHER LOW PRESSURE SYSTEM
APPROACHING FROM THE MID-WEST. THE RIDGE OF HIGH PRESSURE WILL
PUSH TO THE EAST TOWARDS THE CANADIAN MARITIMES EARLY THURSDAY.
WITH CONTINUED CLOUDS...THREAT OF PRECIP WILL RETURN EARLY
THURSDAY...WITH A RETURN TO SOUTHERLY FLOW REINFORCING WAA. 925MB
TEMPS INCREASING TO 13C-17C...WARMING SFC TEMPS INTO THE M50S-
M60S. THE AFOREMENTIONED SFC LOW WILL TRACK TO OUR EAST...KEEPING
WAA AND SOUTHERLY FLOW OVER THE NORTH COUNTRY THURSDAY NIGHT INTO
FRIDAY BEFORE THE ASSOCIATED COLD FRONT BEGINS TO MOVE INTO THE
NORTH COUNTRY FROM THE WEST...BRINGING INCREASING THREAT FOR TS
AS TEMP LAPSE RATES INCREASE. FRONT WILL CONTINUE TO TRAVERSE
OVER THE REGION FRIDAY NIGHT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 06Z MONDAY...BKN/OVC VFR/MVFR CONDS EXPECTED THROUGH MUCH
OF THE PERIOD WITH OCCNL IFR AT KSLK TERMINAL. UPPER SHORTWAVE TO
PASS THROUGH THE REGION TODAY WITH SCATTERED TO NUMEROUS RAIN AND
SNOW SHOWER ACTIVITY. ACTIVITY SHOULD WANE FROM SW TO NE THROUGH
THE AFTERNOON HOURS...TAPERING OFF BY THIS EVENING. WINDS LIGHT TO
MODERATE SOUTH TO SOUTHWESTERLY 5 TO 10 KNOTS WITH OCCNL GUSTS TO
14-18 KNOTS.
OUTLOOK 00Z MONDAY THROUGH THURSDAY...
00Z MONDAY THROUGH 12Z TUESDAY...VFR CONDITIONS EXPECTED AS A
RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION. SCT SHOWERS MAY
AFFECT KMSS LATE IN THE PERIOD.
12Z TUESDAY THROUGH 06Z THURSDAY...BKN/OVC VFR/MVFR CONDITIONS
WITH BRIEF IFR POSSIBLE IN RAIN SHOWERS AS A COLD FRONT MOVES
THROUGH THE REGION.
06Z THURSDAY ONWARD...WARM FRONT WILL BRING MORE RAIN SHOWERS TO THE
REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...BANACOS/LAHIFF
SHORT TERM...RJS
LONG TERM...KGM
AVIATION...JMG/SISSON
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
1250 AM EDT SUN APR 14 2013
.SYNOPSIS...
UPPER LEVEL LOW PRESSURE OVER THE NORTHERN GREAT LAKES WILL BE THE
DOMINANT WEATHER FEATURE ACROSS THE NORTH COUNTRY THIS WEEKEND AS IT
SHIFTS EASTWARD ACROSS SOUTHERN ONTARIO AND QUEBEC. THE LOW WILL BE
ACCOMPANIED BY SCATTERED RAIN AND SNOW SHOWERS. HIGH PRESSURE AND
DRY CONDITIONS RETURN FOR MONDAY.TEMPERATURES WILL BE A BIT BELOW
NORMAL THROUGH SUNDAY...BUT THEN WARM TO ABOVE SEASONAL LEVELS
MONDAY.
&&
.NEAR TERM /UNTIL 8 AM THIS MORNING/...
AS OF 1249 AM EDT SUNDAY...INHERITED FORECAST IN GOOD SHAPE WITH
ONLY AN INCREASE TO POPS AND WX NEEDED TO ACCOUNT FOR MORE
SCATTERED RAIN/SNOW SHOWERS OVERNIGHT AND SUNDAY. PREVIOUS
DISCUSSION FOLLOWS...
VIGOROUS MID-LEVEL VORT MAX EVIDENT ON WV IMAGERY NEAR LAKE
ONTARIO AT 2230Z WILL LIFT NEWD ACROSS OUR FORECAST AREA DURING
THE LATE EVENING HOURS. ASSOCIATED BANDS OF SHOWERS WILL ACCOMPANY
THIS FEATURE...AIDED BY SWLY UPSLOPE FLOW IN THE NRN ADIRONDACKS
WHERE QPF SHOULD BE THE GREATEST (BUT STILL ONLY 0.1-0.2").
FREEZING LEVELS INITIALLY AROUND 2000 FT PER RAP SOUNDINGS...BUT
SHOULD DROP TO NEAR 1000 FT DURING THE PRE-DAWN HOURS.
THUS...LOOKING FOR SCATTERED VALLEY RAIN SHOWERS GOING TO A
RAIN/SNOW SHOWER MIX AFTER MIDNIGHT. ALREADY SEEING -SHSN AT
SARANAC LAKE WHERE THE 23Z TEMP IS 35F. TEMPS SHOULD FALL BELOW
FREEZING ACROSS THE ADIRONDACKS AND N-CENTRAL/NERN VT ALLOWING FOR
A LIGHT SNOW ACCUMULATION OF A DUSTING TO 2" OVERNIGHT...HIGHEST
IN THE NRN ADIRONDACKS WHERE UPSLOPE FLOW WILL LOCALLY AID IN
FREQUENCY OF SNOW SHOWER ACTIVITY. SKIES WILL GENERALLY REMAIN
OVERCAST...THOUGH MODELS INDICATE SOME BINOVC POSSIBLE AROUND
04-06Z ONCE THE VORT MAX PASSES THROUGH. A SECOND UPR WAVE MOVING
IN FROM THE GREAT LAKES FROM 08-12Z SHOULD REESTABLISH OVERCAST
CONDITIONS LATE. GUSTY SW WINDS WILL CONTINUE FOR ANOTHER 1-3
HOURS ACROSS NRN NY (UP TO 30 MPH IN THE ST. LAWRENCE
VALLEY)...BEFORE GRADUALLY SUBSIDING. MIN TEMPS TONIGHT WILL BE
MOSTLY IN THE LOWER TO MID 30S.
&&
.SHORT TERM /8 AM THIS MORNING THROUGH MONDAY NIGHT/...
AS OF 355 PM EDT SATURDAY...AFOREMENTIONED UPPER LEVEL LOW
CONTINUES TO AFFECT THE NORTH COUNTRY SUNDAY AS IT SHIFTS EAST
THROUGH SOUTHERN QUEBEC. SEVERAL MORE PIECES OF SHORTWAVE ENERGY
ROUNDING THE BASE OF THE UPPER TROUGH AS IT DEPARTS WILL KEEP
CHANCES FOR RAIN/SNOW SHOWERS. FLOW TURNS FROM SOUTHWEST TO MORE
WEST AND NORTHWEST DURING SUNDAY...SO BETTER CHANCES FOR
PRECIPITATION WILL BE OVER THE HIGHER TERRAIN AND ACROSS THE
OROGRAPHICALLY FAVORED WESTERN SLOPES. TEMPS REMAIN NEAR NORMAL
WITH HIGHS SUNDAY IN THE MID 40S TO AROUND 50. UPPER TROUGH FINALLY
DEPARTS SUNDAY NIGHT AND UPPER LEVEL RIDGE BUILDS INTO THE
NORTHEAST BY MONDAY. ANY SCATTERED RAIN/SNOW SHOWERS WILL END SUNDAY
EVENING FOLLOWED BY CLEARING. ON MONDAY...EXPECT A MIX OF CLOUDS AND
SUNSHINE AND NOTICEABLY MILDER TEMPERATURES. MEAN 925 TEMPS RISE TO
+5-10C SUPPORTING HIGHS IN THE UPPER 50S AND LOWER 60S. WINDS WILL
ALSO BE ON THE INCREASE FROM THE SOUTH DURING THE DAY WITH SOME
GUSTS 25-30 MPH LIKELY DURING THE AFTERNOON...ESPECIALLY IN THE
CHAMPLAIN VALLEY. SOUTHERLY FLOW CONTINUES TO INCREASE MONDAY NIGHT
AS SURFACE HIGH MOVES FURTHER EAST AND PRESSURE GRADIENT TIGHTENS IN
ADVANCE OF APPROACHING FRONTAL SYSTEM. EXPECT AN INCREASE IN CLOUDS
WITH A CHANCE OF SHOWERS OVERNIGHT...MAINLY OVER NORTHERN TIER OF
ZONES. NON-DIURNAL TEMPERATURE TRENDS LIKELY ACROSS MUCH OF THE AREA
WHERE LOWS WILL BE MAINLY IN THE 40S...AND NOT MUCH BELOW 50 IN
SAINT LAWRENCE VALLEY. EXCEPTION WILL BE EAST OF THE GREEN WHERE
DECOUPLING EXPECTED...ALLOWING FOR LOWS IN THE 30S.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 402 PM EDT SATURDAY...ACTIVE PATTERN DURING THE LONG TERM
WITH WARMER TEMPERATURES AND THREAT OF CONVECTION. GFS AND ECMWF
SHOWING GENERAL AGREEMENT WITH SOME TIMING DIFFERENCES.
HIGH PRESSURE SLIDES FURTHER INTO THE ATLANTIC AS COLD FRONT
PUSHES THROUGH THE NORTH COUNTRY TUESDAY INTO TUESDAY NIGHT.
PLENTY OF SOUTHERLY FLOW AHEAD OF THE FRONT...AT 10-20 KTS...WILL
FILTER IN WARM MOIST AIR. 1000-850MB TEMP LAPSE RATES WILL REACH
8+ C/KM ON TUESDAY...HAVE INCLUDED SLGT CHC TS. AS SFC TEMPS
REACHING LOW 60S IN THE VALLEYS AND MID 50S IN THE HIGH TRRN.
WINDS WILL SHIFT SW-W BEHIND THE FRONT WILL CLOUDS REMAINING OVER
NIGHT...KEEPING MIN TEMPS IN THE M30S-M40S.
GFS PUSHING THE FRONT THROUGH FASTER THAN ECMWF...EDGING IN HIGH
PRESSURE BY WEDNESDAY MORNING. GIVEN PROXIMITY OF UPPER LEVEL
VORTICITY...WILL KEEP CLOUDS OVER THE REGION. 925MB TEMPS OF 7C-
12C ON TUESDAY WILL COOL TO 4C-6C ON WEDNESDAY BEHIND THE FRONT
WITH DISSIPATING THREAT OF PRECIP EARLY WEDNESDAY. MAX TEMPS ON
WEDNESDAY COOLER...IN THE 50S.
OVERNIGHT WEDNESDAY NIGHT...THE COLD FRONT WILL BEGIN TO LIFT
BACK NORTH AS A WARM FRONT WITH ANOTHER LOW PRESSURE SYSTEM
APPROACHING FROM THE MID-WEST. THE RIDGE OF HIGH PRESSURE WILL
PUSH TO THE EAST TOWARDS THE CANADIAN MARITIMES EARLY THURSDAY.
WITH CONTINUED CLOUDS...THREAT OF PRECIP WILL RETURN EARLY
THURSDAY...WITH A RETURN TO SOUTHERLY FLOW REINFORCING WAA. 925MB
TEMPS INCREASING TO 13C-17C...WARMING SFC TEMPS INTO THE M50S-
M60S. THE AFOREMENTIONED SFC LOW WILL TRACK TO OUR EAST...KEEPING
WAA AND SOUTHERLY FLOW OVER THE NORTH COUNTRY THURSDAY NIGHT INTO
FRIDAY BEFORE THE ASSOCIATED COLD FRONT BEGINS TO MOVE INTO THE
NORTH COUNTRY FROM THE WEST...BRINGING INCREASING THREAT FOR TS
AS TEMP LAPSE RATES INCREASE. FRONT WILL CONTINUE TO TRAVERSE
OVER THE REGION FRIDAY NIGHT.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
THROUGH 00Z MONDAY...TWO PERIODS OF MVFR AND LOCALLY IFR IN
SHOWERS OF RAIN AND SNOW.
THE FIRST IS OCCURRING NOW WITH A MIX OF RAIN AT THE LOWER
ELEVATION AND SNOW HIGHER AS THE FIRST OF TWO UPPER LEVEL TROUGHS
MOVE THROUGH THE REGION.
THE SECOND WILL MOVE THROUGH ROUGHLY 06Z-14Z WITH ANOTHER PERIOD
OF SHOWERY PRECIPITATION. THERE MAY BE MORE SNOW MIXED IN WITH
THAT BATCH AS TEMPERATURES FALL SLIGHTLY OVERNIGHT.
ANY ACCUMULATIONS WILL BE LIGHT WITH LESS THAN HALF AN INCH
EXPECTED.
CONDITIONS WILL IMPROVE TO VFR BY MID SUNDAY MORNING...BUT YET
ANOTHER DISTURBANCE LOOKS TO AFFECT THE NORTH COUNTRY...KEEPING
SKIES BKN-OVC.
W-SW WINDS OF 6-12G20KTS WILL SHIFT MORE WSW-W OVERNIGHT AT 10KTS
OR LESS.
OUTLOOK 18Z SUNDAY THROUGH THURSDAY...
18Z SUNDAY THROUGH 00Z MONDAY...CONTINUED UNSETTLED CONDITIONS
WITH A MIX OF MVFR/VFR LIKELY AS AN UPPER LOW OVER CANADA
PRODUCES SCATTERED RAIN AND SNOW SHOWERS...WITH SNOW SHOWERS
MAINLY OVER THE HIGHER ELEVATIONS OF THE ADIRONDACKS AND GREEN
MOUNTAINS.
00Z MONDAY THROUGH 12Z TUESDAY...VFR CONDITIONS EXPECTED AS A
RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION. SCT SHOWERS MAY
AFFECT KMSS LATE IN THE PERIOD.
12Z TUESDAY THROUGH 06Z THURSDAY...BKN/OVC VFR/MVFR CONDITIONS
WITH BRIEF IFR POSSIBLE IN RAIN SHOWERS AS A COLD FRONT MOVES
THROUGH THE REGION.
06Z THURSDAY ONWARD...WARM FRONT WILL BRING MORE RAIN SHOWERS TO THE
REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...BANACOS/LAHIFF
SHORT TERM...RJS
LONG TERM...KGM
AVIATION...KGM/SISSON
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
139 PM CDT SUN APR 14 2013
.UPDATE...
ISSUED AT 139 PM CDT SUN APR 14 2013
MAIN CHANGE FOR THIS UPDATE IS TO THROW THE SOUTHWESTERN COUNTIES
INTO A BLIZZARD WARNING. VIS HAVE BEEN UP AND DOWN IN RANSOM AND
SARGENT COUNTIES DUE TO THE VARIOUS INTENSITY OF THE BANDS MOVING
THROUGH. HOWEVER...REGIONAL RADAR SHOWS QUITE A BIT MORE SNOW
MOVING SLOWLY NORTH OUT OF SOUTH DAKOTA. GUSTS ARE ABOVE 35 MPH IN
MANY SPOTS...EVEN AS FAR NORTH AS VALLEY CITY WHERE THE VIS HAS
NOT QUITE GONE DOWN YET. HOWEVER...ND DOT HAS REPORTED THAT PLOWS
HAVE BEEN PULLED DUE TO POOR VIS SOUTH OF VALLEY CITY AND THE
HEAVY SNOW WILL CONTINUE TO MOVE NORTH INTO GRIGGS AND EDDY COUNTY
THIS AFTERNOON. SNOW WILL BE INCREASING AND WINDS CONTINUING
THROUGH AT LEAST 03Z WHEN THE CENTER OF THE SFC LOW ENTERS THE
SOUTHERN FORECAST AREA. WILL INCLUDE OUR SOUTHWESTERN COUNTIES IN
BLIZZARD FOR A WHILE THIS EVENING BEFORE CONVERTING BACK TO WINTER
STORM AS WINDS SHOULD GO DOWN BUT SNOWFALL CONTINUES.
OTHER CHANGES INCLUDED SLOWING DOWN NORTHWARD PROGRESSION OF POPS
A BIT MORE AND TRIMMING SNOW TOTALS A BIT IN THE SOUTHEASTERN
COUNTIES WHERE THEY MAY GET THE DRY SLOT LATER TONIGHT. OTHER
UPDATE ISSUED AT 959 AM CDT SUN APR 14 2013
TIMING OF THE INCOMING SNOW AND WHAT TO DO ABOUT THE WINTER
HEADLINES CONTINUES TO BE THE MAIN ISSUE. THE NORTHWARD
PROGRESSION OF ACCUMULATING SNOW CONTINUES TO SLOW...WITH THE
RECENT SHORT RANGE MODELS AND RADAR TRENDS BEARING THIS OUT. ONLY
A FEW FLURRIES HAVE PROGRESSED AS FAR NORTH AS VALLEY CITY...AND
THE NAM...RAP...AND HRRR ARE ALL IN PRETTY GOOD AGREEMENT OF
ACCUMULATING SNOW NOT REALLY STARTING IN FAR UNTIL THE 18-21Z TIME
FRAME AND EVEN LATER FURTHER NORTH. ON THE OTHER HAND...HEAVIER
RADAR RETURNS HAVE ENTERED SARGENT COUNTY AND THE FORMAN WEB CAM
SHOWS CONDITIONS DETERIORATING RAPIDLY. FOR NOW...WILL LEAVE THE
HEADLINES ALONE BUT SLOW DOWN THE TIMING OF POPS AGAIN. WILL
UPDATE THE WSW WORDING TO SLOW THE TIMING A BIT AND MENTION A
RAPID CHANGE FROM DECENT CONDITIONS TO NEAR BLIZZARD AS HEAVY SNOW
ACTUALLY ARRIVES.
UPDATE ISSUED AT 645 AM CDT SUN APR 14 2013
THE MAIN CHALLENGE WILL BE TO DELAY THE START TIME OF THE WINTER
STORM WARNINGS...WITH SNOW STARTING LATER IN ALL AREAS.
SNOW...HEAVY AT TIMES WILL MOVE INTO THE SOUTHERN RED RIVER VALLEY
THIS MORNING...SPREADING TO THE CANADIAN BORDER BY LATE THIS
AFTERNOON. WE WILL ALSO EXTEND THE WINTER STORM WARNING UNTIL
18Z MON WITH A SLOWER MOVING SYSTEM. CONDITIONS WILL DETERIORATE
RAPIDLY TODAY ONCE HEAVY SNOW BEGINS...AND WINDS INCREASE. WE
WILL NEED TO MONITOR THE POTENTIAL FOR BLIZZARD CONDITIONS...AND
HAVE MENTIONED NEAR BLIZZARD CONDITIONS IN THE WSW MAINLY ALONG
AND WEST OF THE RED RIVER VALLEY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM CDT SUN APR 14 2013
THE MAIN CHALLENGE CONTINUES TO BE IMPENDING WINTER STORM. MODELS
HAVE TRENDED SLOWER AND A BIT FURTHER SOUTH WITH THE SFC/UPPER
LEVEL LOW TRACKS. FOR NOW WILL MAINTAIN ALL HEADLINE
TIMING...ALTHOUGH SNOW WILL BE DELAYED AND WILL REFLECT THIS IN
THE GRIDS.
FOR TODAY...STRONG FORCING FOR ASCENT PER QG/OMEGA FIELDS WILL
MOVE FROM SOUTH TO NORTH THROUGH THE DAY. EXPECT SNOW...HEAVY AT
TIMES ALONG WITH BLOWING/DRIFTING SNOW. THERE WILL BE TIMES OF
NEAR BLIZZARD CONDITIONS POSSIBLE MAINLY IN EASTERN ND WHERE HEAVY
SNOW RATES ARE POSSIBLE ALONG WITH WINDS GUSTING TO NEAR 40 MPH.
THEREFORE...TRAVEL WILL BECOME DIFFICULT WHEN SNOW BEGINS. FURTHER
NORTH NEAR THE CANADIAN BORDER...SNOW MAY NOT BEGIN UNTIL NEAR
00Z. SNOW SHOULD BEGIN NEAR GFK AROUND 20Z...AND AROUND 16Z IN FARGO.
FOR TONIGHT...AS THE LOW LIFTS SLOWLY NORTH AND EAST...EXPECT A
LARGE DEFORMATION SNOW BAND FOR THE REGION. SNOW COULD BE HEAVY
THIS EVENING ALONG WITH CONSIDERABLE BLOWING/DRIFTING AND NEAR
BLIZZARD CONDITIONS POSSIBLE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 14 2013
ON MONDAY...THE STORM SYSTEM WILL SLOWLY MOVE AWAY FROM THE REGION
BY AFTERNOON. GIVEN THE SLOW START TO THE STORM...SNOW WILL
CONTINUE IN THE NORTH THROUGH 18Z AT LEAST...AND HAVE INCREASED
SNOW CHANCES HERE. WINDS SHOULD SLOWLY DIMINISH AS THE PRESSURE
GRADIENT WEAKENS BY AFTERNOON.
FOR TUESDAY...EXPECT SOME LINGERING LIGHT SNOW IN THE NORTH NEAR
WEAK CYCLONIC FLOW. TEMPS WILL CONTINUE WELL BELOW NORMAL FOR MID
APRIL AS WINTER LIKE CONDITIONS REMAIN OVER THE REGION ALONG WITH
A FRESH SNOW PACK.
ATTENTION ON WEDNESDAY TURNS TO ANOTHER DEVELOPING SYSTEM TO THE
WEST. 00Z MODELS CONTINUE TO INDICATE A PROGRESSIVE LONGWAVE TROUGH
OVER THE ROCKIES WITH SHORTWAVE ENERGY BEGINNING TO LIFT OUT INTO
THE PLAINS...AND SFC CYCLOGENESIS TAKING PLACE OVER THE SOUTHERN
HIGH PLAINS. THIS SYSTEM IS EXPECTED TO LIFT NORTHEAST ALONG THE
LOW-LEVEL BAROCLINIC ZONE LATER WEDNESDAY AND THURSDAY. IN RECENT
DAYS...THE OPERATIONAL MODELS HAVE NOT BEEN CONSISTENT IN THE
EVOLUTION OF SHORTWAVE ENERGY THROUGH THE BROADER TROUGH. THE 00Z
GEM/GFS AND ESPECIALLY THE 18Z DGEX SUGGEST A SLOWER AND FARTHER
NORTH SOLUTION COMPARED WITH THE ECMWF... AND THUS WOULD YIELD
BETTER SNOW CHANCES FOR THE REGION. TIME OF YEAR AND STRONG
DOWNSTREAM RIDGING WOULD SUPPORT A FARTHER NORTH SOLUTION...BUT
OVERALL CONFIDENCE ON THE TRACK/TIMING IS STILL LOW...GIVEN THE LACK
OF MODEL CONSISTENCY. THE SYSTEM BEARS WATCHING...THOUGH. WILL KEEP
THE HIGHEST POPS ACROSS THE SOUTHEAST HALF OF THE REGION...IN
AGREEMENT WITH THE OVERALL MODEL CONSENSUS...WITH PRECIP CHANCES
LINGERING INTO THURSDAY NIGHT.
OTHERWISE...TEMPS ARE EXPECTED TO REMAIN MUCH BELOW MID-APRIL
AVERAGES...WITH NORTHWEST FLOW ALOFT. HIGH TEMPS LIKELY WILL REMAIN
IN 30S FOR MUCH OF THE PERIOD WITH LOWS IN THE 20S.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 139 PM CDT SUN APR 14 2013
HEAVY SNOW WILL MOVE FROM SOUTH TO NORTH THIS AFTERNOON AND THROUGH
THE NIGHT...ALONG WITH INCREASING EASTERLY WINDS. THE OVERALL SYSTEM
IS MOVING MUCH SLOWER THAN PREVIOUSLY FORECAST SO THAT HEAVY SNOW
ONSET HAS BEEN DELAYED 3 TO 6 HOURS COMPARED TO THE 12 UTC TAFS.
WINDS WILL GUST OVER 30 KTS AT TIMES THIS AFTERNOON AND OVERNIGHT...
AND TURN MORE NORTHERLY LATER TONIGHT. EXPECT IFR CONDITIONS WITH
THE HEAVIEST SNOW BANDS ALONG WITH BLOWING SNOW AND VISIBILITY
REDUCTIONS TO 1/4 MILE OR LESS. CONDITIONS WILL BE SLOW TO IMPROVE
THROUGH THE DAY ON MONDAY...ESPECIALLY AT KDVL...KGFK AND KTVF.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING FROM 10 PM THIS EVENING TO 1 PM CDT MONDAY
FOR NDZ024-028-038-049-052.
BLIZZARD WARNING UNTIL 10 PM CDT THIS EVENING FOR NDZ024-028-038-
049-052.
WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR NDZ029-030-039-
053.
WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR NDZ006>008-
014>016-026-027-054.
MN...WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR MNZ002-003-
022>024-027>032-040.
WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR MNZ001-004>009-
013>017.
&&
$$
UPDATE...JR
SHORT TERM...DK
LONG TERM...MAKOWSKI
AVIATION...ROGERS
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1002 AM CDT SUN APR 14 2013
.UPDATE...
ISSUED AT 959 AM CDT SUN APR 14 2013
TIMING OF THE INCOMING SNOW AND WHAT TO DO ABOUT THE WINTER
HEADLINES CONTINUES TO BE THE MAIN ISSUE. THE NORTHWARD
PROGRESSION OF ACCUMULATING SNOW CONTINUES TO SLOW...WITH THE
RECENT SHORT RANGE MODELS AND RADAR TRENDS BEARING THIS OUT. ONLY
A FEW FLURRIES HAVE PROGRESSED AS FAR NORTH AS VALLEY CITY...AND
THE NAM...RAP...AND HRRR ARE ALL IN PRETTY GOOD AGREEMENT OF
ACCUMULATING SNOW NOT REALLY STARTING IN FAR UNTIL THE 18-21Z TIME
FRAME AND EVEN LATER FURTHER NORTH. ON THE OTHER HAND...HEAVIER
RADAR RETURNS HAVE ENTERED SARGENT COUNTY AND THE FORMAN WEB CAM
SHOWS CONDITIONS DETERIORATING RAPIDLY. FOR NOW...WILL LEAVE THE
HEADLINES ALONE BUT SLOW DOWN THE TIMING OF POPS AGAIN. WILL
UPDATE THE WSW WORDING TO SLOW THE TIMING A BIT AND MENTION A
RAPID CHANGE FROM DECENT CONDITIONS TO NEAR BLIZZARD AS HEAVY SNOW
ACTUALLY ARRIVES.
UPDATE ISSUED AT 645 AM CDT SUN APR 14 2013
THE MAIN CHALLENGE WILL BE TO DELAY THE START TIME OF THE WINTER
STORM WARNINGS...WITH SNOW STARTING LATER IN ALL AREAS.
SNOW...HEAVY AT TIMES WILL MOVE INTO THE SOUTHERN RED RIVER VALLEY
THIS MORNING...SPREADING TO THE CANADIAN BORDER BY LATE THIS
AFTERNOON. WE WILL ALSO EXTEND THE WINTER STORM WARNING UNTIL
18Z MON WITH A SLOWER MOVING SYSTEM. CONDITIONS WILL DETERIORATE
RAPIDLY TODAY ONCE HEAVY SNOW BEGINS...AND WINDS INCREASE. WE
WILL NEED TO MONITOR THE POTENTIAL FOR BLIZZARD CONDITIONS...AND
HAVE MENTIONED NEAR BLIZZARD CONDITIONS IN THE WSW MAINLY ALONG
AND WEST OF THE RED RIVER VALLEY.
&&
.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 330 AM CDT SUN APR 14 2013
THE MAIN CHALLENGE CONTINUES TO BE IMPENDING WINTER STORM. MODELS
HAVE TRENDED SLOWER AND A BIT FURTHER SOUTH WITH THE SFC/UPPER
LEVEL LOW TRACKS. FOR NOW WILL MAINTAIN ALL HEADLINE
TIMING...ALTHOUGH SNOW WILL BE DELAYED AND WILL REFLECT THIS IN
THE GRIDS.
FOR TODAY...STRONG FORCING FOR ASCENT PER QG/OMEGA FIELDS WILL
MOVE FROM SOUTH TO NORTH THROUGH THE DAY. EXPECT SNOW...HEAVY AT
TIMES ALONG WITH BLOWING/DRIFTING SNOW. THERE WILL BE TIMES OF
NEAR BLIZZARD CONDITIONS POSSIBLE MAINLY IN EASTERN ND WHERE HEAVY
SNOW RATES ARE POSSIBLE ALONG WITH WINDS GUSTING TO NEAR 40 MPH.
THEREFORE...TRAVEL WILL BECOME DIFFICULT WHEN SNOW BEGINS. FURTHER
NORTH NEAR THE CANADIAN BORDER...SNOW MAY NOT BEGIN UNTIL NEAR
00Z. SNOW SHOULD BEGIN NEAR GFK AROUND 20Z...AND AROUND 16Z IN FARGO.
FOR TONIGHT...AS THE LOW LIFTS SLOWLY NORTH AND EAST...EXPECT A
LARGE DEFORMATION SNOW BAND FOR THE REGION. SNOW COULD BE HEAVY
THIS EVENING ALONG WITH CONSIDERABLE BLOWING/DRIFTING AND NEAR
BLIZZARD CONDITIONS POSSIBLE.
.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM CDT SUN APR 14 2013
ON MONDAY...THE STORM SYSTEM WILL SLOWLY MOVE AWAY FROM THE REGION
BY AFTERNOON. GIVEN THE SLOW START TO THE STORM...SNOW WILL
CONTINUE IN THE NORTH THROUGH 18Z AT LEAST...AND HAVE INCREASED
SNOW CHANCES HERE. WINDS SHOULD SLOWLY DIMINISH AS THE PRESSURE
GRADIENT WEAKENS BY AFTERNOON.
FOR TUESDAY...EXPECT SOME LINGERING LIGHT SNOW IN THE NORTH NEAR
WEAK CYCLONIC FLOW. TEMPS WILL CONTINUE WELL BELOW NORMAL FOR MID
APRIL AS WINTER LIKE CONDITIONS REMAIN OVER THE REGION ALONG WITH
A FRESH SNOW PACK.
ATTENTION ON WEDNESDAY TURNS TO ANOTHER DEVELOPING SYSTEM TO THE
WEST. 00Z MODELS CONTINUE TO INDICATE A PROGRESSIVE LONGWAVE TROUGH
OVER THE ROCKIES WITH SHORTWAVE ENERGY BEGINNING TO LIFT OUT INTO
THE PLAINS...AND SFC CYCLOGENESIS TAKING PLACE OVER THE SOUTHERN
HIGH PLAINS. THIS SYSTEM IS EXPECTED TO LIFT NORTHEAST ALONG THE
LOW-LEVEL BAROCLINIC ZONE LATER WEDNESDAY AND THURSDAY. IN RECENT
DAYS...THE OPERATIONAL MODELS HAVE NOT BEEN CONSISTENT IN THE
EVOLUTION OF SHORTWAVE ENERGY THROUGH THE BROADER TROUGH. THE 00Z
GEM/GFS AND ESPECIALLY THE 18Z DGEX SUGGEST A SLOWER AND FARTHER
NORTH SOLUTION COMPARED WITH THE ECMWF... AND THUS WOULD YIELD
BETTER SNOW CHANCES FOR THE REGION. TIME OF YEAR AND STRONG
DOWNSTREAM RIDGING WOULD SUPPORT A FARTHER NORTH SOLUTION...BUT
OVERALL CONFIDENCE ON THE TRACK/TIMING IS STILL LOW...GIVEN THE LACK
OF MODEL CONSISTENCY. THE SYSTEM BEARS WATCHING...THOUGH. WILL KEEP
THE HIGHEST POPS ACROSS THE SOUTHEAST HALF OF THE REGION...IN
AGREEMENT WITH THE OVERALL MODEL CONSENSUS...WITH PRECIP CHANCES
LINGERING INTO THURSDAY NIGHT.
OTHERWISE...TEMPS ARE EXPECTED TO REMAIN MUCH BELOW MID-APRIL
AVERAGES...WITH NORTHWEST FLOW ALOFT. HIGH TEMPS LIKELY WILL REMAIN
IN 30S FOR MUCH OF THE PERIOD WITH LOWS IN THE 20S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 613 AM CDT SUN APR 14 2013
HEAVY SNOW WILL MOVE FROM SOUTH TO NORTH TODAY...ALONG WITH
INCREASING EASTERLY WINDS. WINDS WILL GUST OVER 30KT AT TIMES THIS
AFTERNOON AND OVERNIGHT...AND TURN MORE NORTHERLY LATER TONIGHT.
EXPECT IFR CONDITIONS POSSIBLE NEAR ANY SNOW BANDS ALONG WITH
BLOWING SNOW POSSIBLE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR NDZ049-052-053.
WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR NDZ028>030-038-
039.
WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 1 PM CDT MONDAY
FOR NDZ006>008-014>016-024-026-027-054.
MN...WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR MNZ029>032-040.
WINTER STORM WARNING UNTIL 1 PM CDT MONDAY FOR MNZ002-003-
022>024-027-028.
WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 1 PM CDT MONDAY
FOR MNZ001-004>009-013>017.
&&
$$
UPDATE...JR
SHORT TERM...DK
LONG TERM...MAKOWSKI
AVIATION...DK
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
641 AM EDT SUN APR 14 2013
.SYNOPSIS...
A WARM FRONT WILL PUSH NORTHEAST ACROSS THE REGION TODAY. A COLD
FRONT WILL SLOWLY APPROACH THE WESTERN GREAT LAKES FROM THE WEST
TONIGHT INTO MONDAY. THE FRONT IS THEN FORECAST TO SAG INTO THE
REGION MONDAY NIGHT INTO TUESDAY...EVENTUALLY STALLING OUT NEAR
THE OHIO RIVER BY WEDNESDAY. THE FRONT WILL PROVIDE THE FOCUS FOR
SHOWERS AND THUNDERSTORMS THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL PUSH OFF TO THE EAST/NORTHEAST TODAY AS A WARM
FRONT LIFTS NORTHEAST THROUGH THE REGION. WAA INDUCED CLOUDS WILL
SPREAD QUICKLY INTO THE AREA THIS MORNING. KILN RADAR WAS SHOWING
SHOWERS MOVING INTO THE WRN CWFA. SHOWERS ARE NOW ENCROACHING THE
CINCY METRO AREA SO HAVE EXPANDED CHANCE POPS TO THE SOUTH OF
PREVIOUS FORECAST. LATEST HRRR PUSHES THESE SHOWERS INTO THE
WHITEWATER/MIAMI VALLEY...WEST CENTRAL AND PARTS OF CENTRAL OHIO
DURING THE MORNING HOURS. HAVE INCLUDED A CHANCE OF SHOWERS HERE
AS WELL. OTHERWISE...SKIES SHOULD BECOME MOSTLY SUNNY BY AFTERNOON
AS SOUTHERLY WINDS INCREASE. TEMPERATURES WILL HAVE A SLOW START
DUE TO COOL OVERNIGHT LOWS AND CLOUDS...BUT WE SHOULD SEE A LATE
WARM PUSH WITH SUNSHINE AND SOUTHERLY WINDS. HIGHS WILL RANGE FROM
THE MID 60S FAR NORTH TO THE LOWER 70S SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
FORECAST AREA WILL BE WEDGED BETWEEN A S/WV MOVING ACRS THE SE
U.S. AND A STORM SYSTEM ACRS THE NORTHERN PLAINS/UPR MS RIVER VLY
TONIGHT. SKIES WILL BE MOSTLY CLEAR EARLY WITH INCREASING CLOUDS
LATE AS MOISTURE BEGINS TO SEEP NORTHWARD INTO THE OHIO VALLEY.
FOR MONDAY...A COLD FRONT WILL SLOWLY APPROACH THE REGION FROM THE
WEST. A MIX OF CLOUDS AND SUN ALONG WITH SOUTHERLY FLOW SHOULD
BOOST TEMPERATURES INTO THE LOWER AND MID 70S. SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE FRONT SHOULD HOLD OFF FOR THE
MOST PART ACRS THE FAR NW CWFA...BUT WE SHOULD SEE CHANCES
INCREASE TOWARD MONDAY EVENING. THE FRONT IS EXPECTED TO SAG
SLOWLY INTO THE NRN ZONES MONDAY NIGHT...BRINGING AN INCREASING
THREAT FOR SHOWERS AND STORMS HERE AS A MODEST LOW LEVEL JET AND
FRONTAL CONVERGENCE OCCUR.
FOR THE PERIOD TUESDAY INTO TUESDAY NIGHT...MODELS CONTINUE TO
OFFER DIFFERENT SOLUTIONS IN THE TIMING OF THE FRONT AS IT SINKS
SOUTH TOWARD THE OHIO RIVER. THE TIMING WILL HAVE SIGNIFICANT PCPN
AND TEMPERATURE IMPLICATIONS AS THOSE ON THE COOL SIDE OF THE
BOUNDARY WILL SEE MUCH COOLER TEMPERATURES VERSUS THOSE ON THE
WARM SIDE. WILL KEEP LIKELY POPS GOING ACRS THE NRN ZONES TUESDAY
MORNING AND THEN WILL TAPER POPS TO A CHANCE REGION WIDE AS IT IS
HARD TO DISCERN ANY EMBEDDED IMPULSES ALOFT TO AID FRONTAL
CONVERGENCE FOR SHOWER/STORM ACTIVITY. AGAIN...MODELS SUGGEST THAT
THE FRONT WILL STALL OUT NEAR OR SOUTH OF THE OHIO BY WEDNESDAY
MORNING.
FOR WEDNESDAY INTO WEDNESDAY NIGHT...FRONT SHOULD BEGIN TO LIFT
BACK NORTH AS A WARM FRONT AS A STRONGER S/WV AND ASSOCD MID LVL
TROF EJECT FROM THE FOUR CORNERS REGION INTO THE PLAINS...WHICH
WILL FORCE THE MID LVL FLOW TO BUCKLE ACRS OUR REGION. WILL
CONTINUE WITH THE CHANCE OF SHOWERS AND STORMS.
AS FOR TEMPERATURES FOR THE REMAINDER OF THE PERIOD...HAVE TAKEN
A CONSENSUS OF RAW MODEL VALUES GIVEN THE UNCERTAINTY OF THE
PLACEMENT OF THE FRONT.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AN UPPER LEVEL TROUGH WILL PIVOT INTO THE AREA LATE IN THE WORK
WEEK. THIS WILL HELP DRIVE A STRONG COLD FRONT THROUGH THE REGION
THURSDAY INTO FRIDAY. THIS WILL RESULT IN AN INCREASING CHANCE OF
THUNDERSTORMS FROM THE WEST THURSDAY AFTERNOON INTO THURSDAY
EVENING. AS THE FRONT MOVES THROUGH THURSDAY NIGHT...THUNDERSTORMS
SHOULD TAPER OFF TO SOME SHOWERS. TEMPERATURES THURSDAY NIGHT INTO
FRIDAY WILL BE TRICKY DEPENDING ON THE TIMING OF THE FRONT...BUT
WILL LIKELY END UP WITH A PERIOD OF NON DIURNAL TEMPS DURING THAT
PERIOD AS MUCH COOLER AIR FILTERS IN BEHIND THE FRONT. SOME WRAP
AROUND MOISTURE COULD LEAD TO A FEW SHOWERS THROUGH THE DAY ON
FRIDAY. DRIER AIR WILL PUSH IN FOR FRIDAY NIGHT AND SATURDAY...BUT
TEMPERATURES WILL REMAIN BELOW NORMAL HEADING INTO THE WEEKEND.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE TAF PERIOD.
HIGH PRESSURE IS DEPARTING THE REGION TO THE EAST...WITH WINDS
BEGINNING TO SWITCH TO A SOUTHEASTERLY DIRECTION. AT THE SAME
TIME...AN AREA OF STRATOCUMULUS (5000-8000 FEET) HAS OVERSPREAD
MUCH OF INDIANA AND OHIO. SOME LIGHT SHOWERS OR SPRINKLES WILL BE
POSSIBLE AT KDAY OVER THE NEXT FEW HOURS...WITH NO SIGNIFICANT
AVIATION IMPACTS EXPECTED.
BY AFTERNOON...MOST OF THE CLOUDS WILL BE HIGH IN THE
ATMOSPHERE...AND SOUTH-SOUTHEASTERLY WINDS WILL GUST INTO THE 15-20
KNOT RANGE. WINDS WILL SHIFT TO MORE OF A SOUTHERLY DIRECTION ON
SUNDAY NIGHT...AS ADDITIONAL MOISTURE MOVES IN FROM THE SOUTH.
THOUGH CEILINGS WILL EVENTUALLY LOWER TO AROUND 4000-5000 FEET
NEAR THE END OF THE TAF PERIOD...VFR CONDITIONS ARE STILL
EXPECTED.
OUTLOOK...SHOWERS AND THUNDERSTORMS ARE POSSIBLE FROM TUESDAY
THROUGH THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
539 AM EDT SUN APR 14 2013
.SYNOPSIS...
A WARM FRONT WILL PUSH NORTHEAST ACROSS THE REGION TODAY. A COLD
FRONT WILL SLOWLY APPROACH THE WESTERN GREAT LAKES FROM THE WEST
TONIGHT INTO MONDAY. THE FRONT IS THEN FORECAST TO SAG INTO THE
REGION MONDAY NIGHT INTO TUESDAY...EVENTUALLY STALLING OUT NEAR
THE OHIO RIVER BY WEDNESDAY. THE FRONT WILL PROVIDE THE FOCUS FOR
SHOWERS AND THUNDERSTORMS THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL PUSH OFF TO THE EAST/NORTHEAST TODAY AS A WARM
FRONT LIFTS NORTHEAST THROUGH THE REGION. WAA INDUCED CLOUDS WILL
SPREAD QUICKLY INTO THE AREA THIS MORNING. KILN RADAR WAS SHOWING
SHOWERS MOVING INTO THE WRN CWFA. SHOWERS ARE NOW ENCROACHING THE
CINCY METRO AREA SO HAVE EXPANDED CHANCE POPS TO THE SOUTH OF
PREVIOUS FORECAST. LATEST HRRR PUSHES THESE SHOWERS INTO THE
WHITEWATER/MIAMI VALLEY...WEST CENTRAL AND PARTS OF CENTRAL OHIO
DURING THE MORNING HOURS. HAVE INCLUDED A CHANCE OF SHOWERS HERE
AS WELL. OTHERWISE...SKIES SHOULD BECOME MOSTLY SUNNY BY AFTERNOON
AS SOUTHERLY WINDS INCREASE. TEMPERATURES WILL HAVE A SLOW START
DUE TO COOL OVERNIGHT LOWS AND CLOUDS...BUT WE SHOULD SEE A LATE
WARM PUSH WITH SUNSHINE AND SOUTHERLY WINDS. HIGHS WILL RANGE FROM
THE MID 60S FAR NORTH TO THE LOWER 70S SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
FORECAST AREA WILL BE WEDGED BETWEEN A S/WV MOVING ACRS THE SE
U.S. AND A STORM SYSTEM ACRS THE NORTHERN PLAINS/UPR MS RIVER VLY
TONIGHT. SKIES WILL BE MOSTLY CLEAR EARLY WITH INCREASING CLOUDS
LATE AS MOISTURE BEGINS TO SEEP NORTHWARD INTO THE OHIO VALLEY.
FOR MONDAY...A COLD FRONT WILL SLOWLY APPROACH THE REGION FROM THE
WEST. A MIX OF CLOUDS AND SUN ALONG WITH SOUTHERLY FLOW SHOULD
BOOST TEMPERATURES INTO THE LOWER AND MID 70S. SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE FRONT SHOULD HOLD OFF FOR THE
MOST PART ACRS THE FAR NW CWFA...BUT WE SHOULD SEE CHANCES
INCREASE TOWARD MONDAY EVENING. THE FRONT IS EXPECTED TO SAG
SLOWLY INTO THE NRN ZONES MONDAY NIGHT...BRINGING AN INCREASING
THREAT FOR SHOWERS AND STORMS HERE AS A MODEST LOW LEVEL JET AND
FRONTAL CONVERGENCE OCCUR.
FOR THE PERIOD TUESDAY INTO TUESDAY NIGHT...MODELS CONTINUE TO
OFFER DIFFERENT SOLUTIONS IN THE TIMING OF THE FRONT AS IT SINKS
SOUTH TOWARD THE OHIO RIVER. THE TIMING WILL HAVE SIGNIFICANT PCPN
AND TEMPERATURE IMPLICATIONS AS THOSE ON THE COOL SIDE OF THE
BOUNDARY WILL SEE MUCH COOLER TEMPERATURES VERSUS THOSE ON THE
WARM SIDE. WILL KEEP LIKELY POPS GOING ACRS THE NRN ZONES TUESDAY
MORNING AND THEN WILL TAPER POPS TO A CHANCE REGION WIDE AS IT IS
HARD TO DISCERN ANY EMBEDDED IMPULSES ALOFT TO AID FRONTAL
CONVERGENCE FOR SHOWER/STORM ACTIVITY. AGAIN...MODELS SUGGEST THAT
THE FRONT WILL STALL OUT NEAR OR SOUTH OF THE OHIO BY WEDNESDAY
MORNING.
FOR WEDNESDAY INTO WEDNESDAY NIGHT...FRONT SHOULD BEGIN TO LIFT
BACK NORTH AS A WARM FRONT AS A STRONGER S/WV AND ASSOCD MID LVL
TROF EJECT FROM THE FOUR CORNERS REGION INTO THE PLAINS...WHICH
WILL FORCE THE MID LVL FLOW TO BUCKLE ACRS OUR REGION. WILL
CONTINUE WITH THE CHANCE OF SHOWERS AND STORMS.
AS FOR TEMPERATURES FOR THE REMAINDER OF THE PERIOD...HAVE TAKEN
A CONSENSUS OF RAW MODEL VALUES GIVEN THE UNCERTAINTY OF THE
PLACEMENT OF THE FRONT.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AN UPPER LEVEL TROUGH WILL PIVOT INTO THE AREA LATE IN THE WORK
WEEK. THIS WILL HELP DRIVE A STRONG COLD FRONT THROUGH THE REGION
THURSDAY INTO FRIDAY. THIS WILL RESULT IN AN INCREASING CHANCE OF
THUNDERSTORMS FROM THE WEST THURSDAY AFTERNOON INTO THURSDAY
EVENING. AS THE FRONT MOVES THROUGH THURSDAY NIGHT...THUNDERSTORMS
SHOULD TAPER OFF TO SOME SHOWERS. TEMPERATURES THURSDAY NIGHT INTO
FRIDAY WILL BE TRICKY DEPENDING ON THE TIMING OF THE FRONT...BUT
WILL LIKELY END UP WITH A PERIOD OF NON DIURNAL TEMPS DURING THAT
PERIOD AS MUCH COOLER AIR FILTERS IN BEHIND THE FRONT. SOME WRAP
AROUND MOISTURE COULD LEAD TO A FEW SHOWERS THROUGH THE DAY ON
FRIDAY. DRIER AIR WILL PUSH IN FOR FRIDAY NIGHT AND SATURDAY...BUT
TEMPERATURES WILL REMAIN BELOW NORMAL HEADING INTO THE WEEKEND.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL BE THE RULE THROUGH THE TAF PERIOD. HIGH
PRESSURE WILL DEPART THE REGION TO THE EAST OVERNIGHT...ALLOWING
WINDS TO SWITCH TO THE SOUTH-SOUTHEAST DURING THE DAY SUNDAY.
THERE WILL BE MID-CLOUDS OVER THE REGION OVERNIGHT...WITH SOME OF
THEM STAYING IN PLACE INTO THE DAY.
A FEW LIGHT SHOWERS OR SPRINKLES ARE EXPECTED TO DEVELOP OVER
INDIANA DURING THE NEXT FEW HOURS. THESE MAY IMPACT THE DAYTON TAF
SITE NEAR SUNRISE...BUT NO IMPACTS TO AVIATION CONDITIONS ARE EXPECTED.
SUNDAY NIGHT...WINDS WILL SHIFT TO THE SOUTH...AND ADDITIONAL
MOISTURE WILL BEGIN TO WORK INTO THE AREA.
OUTLOOK...SHOWERS AND THUNDERSTORMS ARE POSSIBLE FROM TUESDAY
THROUGH THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
435 AM EDT SUN APR 14 2013
.SYNOPSIS...
A WARM FRONT WILL PUSH NORTHEAST ACROSS THE REGION TODAY. A COLD
FRONT WILL SLOWLY APPROACH THE WESTERN GREAT LAKES FROM THE WEST
TONIGHT INTO MONDAY. THE FRONT IS THEN FORECAST TO SAG INTO THE
REGION MONDAY NIGHT INTO TUESDAY...EVENTUALLY STALLING OUT NEAR
THE OHIO RIVER BY WEDNESDAY. THE FRONT WILL PROVIDE THE FOCUS FOR
SHOWERS AND THUNDERSTORMS THROUGH MID WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HIGH PRESSURE WILL PUSH OFF TO THE EAST/NORTHEAST TODAY AS A WARM
FRONT LIFTS NORTHEAST THROUGH THE REGION. WAA INDUCED CLOUDS WILL
SPREAD QUICKLY INTO THE AREA THIS MORNING. MOSAIC RADAR TO OUR
WEST WAS INDICATING SOME SHOWER ACTIVITY MOVING INTO CENTRAL
INDIANA. LATEST HRRR PUSHES THESE SHOWERS INTO THE
WHITEWATER/MIAMI VALLEY AND WEST CENTRAL OHIO DURING THE MORNING
HOURS. HAVE INCLUDED A CHANCE OF SHOWERS HERE. OTHERWISE...SKIES
SHOULD BECOME MOSTLY SUNNY BY AFTERNOON AS SOUTHERLY WINDS
INCREASE. TEMPERATURES WILL HAVE A SLOW START DUE TO COOL
OVERNIGHT LOWS AND CLOUDS...BUT WE SHOULD SEE A LATE WARM PUSH
WITH SUNSHINE AND SOUTHERLY WINDS. HIGHS WILL RANGE FROM THE MID
60S FAR NORTH TO THE LOWER 70S SOUTH.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
FORECAST AREA WILL BE WEDGED BETWEEN A S/WV MOVING ACRS THE SE
U.S. AND A STORM SYSTEM ACRS THE NORTHERN PLAINS/UPR MS RIVER VLY
TONIGHT. SKIES WILL BE MOSTLY CLEAR EARLY WITH INCREASING CLOUDS
LATE AS MOISTURE BEGINS TO SEEP NORTHWARD INTO THE OHIO VALLEY.
FOR MONDAY...A COLD FRONT WILL SLOWLY APPROACH THE REGION FROM THE
WEST. A MIX OF CLOUDS AND SUN ALONG WITH SOUTHERLY FLOW SHOULD
BOOST TEMPERATURES INTO THE LOWER AND MID 70S. SHOWERS AND
THUNDERSTORMS ASSOCIATED WITH THE FRONT SHOULD HOLD OFF FOR THE
MOST PART ACRS THE FAR NW CWFA...BUT WE SHOULD SEE CHANCES
INCREASE TOWARD MONDAY EVENING. THE FRONT IS EXPECTED TO SAG
SLOWLY INTO THE NRN ZONES MONDAY NIGHT...BRINGING AN INCREASING
THREAT FOR SHOWERS AND STORMS HERE AS A MODEST LOW LEVEL JET AND
FRONTAL CONVERGENCE OCCUR.
FOR THE PERIOD TUESDAY INTO TUESDAY NIGHT...MODELS CONTINUE TO
OFFER DIFFERENT SOLUTIONS IN THE TIMING OF THE FRONT AS IT SINKS
SOUTH TOWARD THE OHIO RIVER. THE TIMING WILL HAVE SIGNIFICANT PCPN
AND TEMPERATURE IMPLICATIONS AS THOSE ON THE COOL SIDE OF THE
BOUNDARY WILL SEE MUCH COOLER TEMPERATURES VERSUS THOSE ON THE
WARM SIDE. WILL KEEP LIKELY POPS GOING ACRS THE NRN ZONES TUESDAY
MORNING AND THEN WILL TAPER POPS TO A CHANCE REGION WIDE AS IT IS
HARD TO DISCERN ANY EMBEDDED IMPULSES ALOFT TO AID FRONTAL
CONVERGENCE FOR SHOWER/STORM ACTIVITY. AGAIN...MODELS SUGGEST THAT
THE FRONT WILL STALL OUT NEAR OR SOUTH OF THE OHIO BY WEDNESDAY
MORNING.
FOR WEDNESDAY INTO WEDNESDAY NIGHT...FRONT SHOULD BEGIN TO LIFT
BACK NORTH AS A WARM FRONT AS A STRONGER S/WV AND ASSOCD MID LVL
TROF EJECT FROM THE FOUR CORNERS REGION INTO THE PLAINS...WHICH
WILL FORCE THE MID LVL FLOW TO BUCKLE ACRS OUR REGION. WILL
CONTINUE WITH THE CHANCE OF SHOWERS AND STORMS.
AS FOR TEMPERATURES FOR THE REMAINDER OF THE PERIOD...HAVE TAKEN
A CONSENSUS OF RAW MODEL VALUES GIVEN THE UNCERTAINTY OF THE
PLACEMENT OF THE FRONT.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
AN UPPER LEVEL TROUGH WILL PIVOT INTO THE AREA LATE IN THE WORK
WEEK. THIS WILL HELP DRIVE A STRONG COLD FRONT THROUGH THE REGION
THURSDAY INTO FRIDAY. THIS WILL RESULT IN AN INCREASING CHANCE OF
THUNDERSTORMS FROM THE WEST THURSDAY AFTERNOON INTO THURSDAY
EVENING. AS THE FRONT MOVES THROUGH THURSDAY NIGHT...THUNDERSTORMS
SHOULD TAPER OFF TO SOME SHOWERS. TEMPERATURES THURSDAY NIGHT INTO
FRIDAY WILL BE TRICKY DEPENDING ON THE TIMING OF THE FRONT...BUT
WILL LIKELY END UP WITH A PERIOD OF NON DIURNAL TEMPS DURING THAT
PERIOD AS MUCH COOLER AIR FILTERS IN BEHIND THE FRONT. SOME WRAP
AROUND MOISTURE COULD LEAD TO A FEW SHOWERS THROUGH THE DAY ON
FRIDAY. DRIER AIR WILL PUSH IN FOR FRIDAY NIGHT AND SATURDAY...BUT
TEMPERATURES WILL REMAIN BELOW NORMAL HEADING INTO THE WEEKEND.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
VFR CONDITIONS WILL BE THE RULE THROUGH THE TAF PERIOD. HIGH
PRESSURE WILL DEPART THE REGION TO THE EAST OVERNIGHT...ALLOWING
WINDS TO SWITCH TO THE SOUTH-SOUTHEAST DURING THE DAY SUNDAY.
THERE WILL BE MID-CLOUDS OVER THE REGION OVERNIGHT...WITH SOME OF
THEM STAYING IN PLACE INTO THE DAY.
A FEW LIGHT SHOWERS OR SPRINKLES ARE EXPECTED TO DEVELOP OVER
INDIANA DURING THE NEXT FEW HOURS. THESE MAY IMPACT THE DAYTON TAF
SITE NEAR SUNRISE...BUT NO IMPACTS TO AVIATION CONDITIONS ARE EXPECTED.
SUNDAY NIGHT...WINDS WILL SHIFT TO THE SOUTH...AND ADDITIONAL
MOISTURE WILL BEGIN TO WORK INTO THE AREA.
OUTLOOK...SHOWERS AND THUNDERSTORMS ARE POSSIBLE FROM TUESDAY
THROUGH THURSDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...HICKMAN
NEAR TERM...HICKMAN
SHORT TERM...HICKMAN
LONG TERM...JGL
AVIATION...HATZOS
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NWS RAPID CITY SD
1107 PM MDT SAT APR 13 2013
.UPDATE...
ISSUED AT 640 PM MDT SAT APR 13 2013
00Z SURFACE MAP PLACES LOW NEAR KGCC. SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS MOVING ACROSS NORTHEAST WYOMING INTO
WESTERN SOUTH DAKOTA. SURFACE LOW TRACKS ACROSS THE BLACK HILLS
AROUND 06Z...AND THEN INTO CENTRAL SOUTH DAKOTA BY 12Z. 18Z
NAM/21Z RAP SHOW STRONG SURFACE PRESSURE FALL/RISE COUPLET MOVING
ACROSS THE BLACK HILLS OVERNIGHT. NAM HAS AREA OF 50KT BOUNDARY
LAYER WINDS ALONG EASTERN SIDE OF THE BLACK HILLS AROUND
09Z...WHILE RAP HAS 40-45KT BOUNDARY LAYER WINDS. NAM/RAP
SOUNDINGS PLACE 50KT WINDS FROM 2000-4000FT AGL AND STEEP LOW
LEVEL LAPSE RATES. AS BEST PRESSURE RISES MOVE THROUGH IN THE WAKE
OF THE LOW...THERE SHOULD BE AN HOUR OR TWO OF WIND GUSTS AROUND
45KT. MAY EVEN SEE PEAK WIND GUST FOR RAPID CITY AROUND 50KTS.
WINDS SHOULD SUBSIDE FOR A WHILE BEFORE PICKING UP AGAIN SUNDAY
MORNING. WILL MOVE UP THE START TIME OF THE WIND ADVISORY TO
ACCOUNT FOR THE STRONGER WINDS IN THE WAKE OF THE LOW. NO CHANGES
EXPECTED AT THIS TIME FOR THE WINTER WEATHER ADVISORY ACROSS FAR
NORTHWEST SOUTH DAKOTA.
&&
.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 335 PM MDT SAT APR 13 2013
CURRENT SURFACE ANALYSIS SHOWS LOW PRESSURE MOVING
SLOWLY EAST ACROSS NORTH CENTRAL MT...WITH WARM FRONT STRETCHING
SOUTHEASTWARD INTO EASTERN WY. COLD FRONT EXTENDS BACK TO THE
SOUTHWEST OF THE LOW ACROSS WESTERN WY. UPPER LEVEL ANALYSIS HAS LOW
OVER NORTHERN GREAT LAKES REGION...WEAK RIDGING OVER THE NORTHERN
PLAINS...AND THE NEXT SYSTEM MOVING EAST-SOUTHEAST ACROSS WESTERN
MT. SKIES ARE NOW MOSTLY CLOUDY ACROSS THE AREA. THERE ARE A WIDE
RANGE OF TEMPS ACROSS THE AREA...WITH MOSTLY UPPER 30S AND LOWER 40S
TO THE EAST AND SOUTHEAST OF THE BLACK HILLS...40S AND 50S ACROSS
MUCH OF NORTHEASTERN WY...THE BLACK HILLS...AND FAR NORTHWESTERN SD.
WINDS ARE SOUTH-SOUTHWEST ACROSS NORTHEASTERN WY AND THE BLACK
HILLS... EAST-SOUTHEAST AND BREEZY TO THE NORTH AND EAST OF THE
BLACK HILLS.
APPROACHING STORM SYSTEM IS THE MAIN FOCUS OF THE SHORT TERM
PERIOD...AS IT TRACKS EAST-SOUTHEAST ACROSS MT AND THE NORTHERN
PLAINS. 12Z MODELS ARE IN BETTER AGREEMENT THAN PREVIOUS RUNS...BUT
STILL SOME MINOR TIMING AND TRACK DIFFERENCES WHICH WOULD AFFECT
NORTHERN PORTIONS OF THE CWA...ESPECIALLY NORTHWESTERN SD. LOOKING
AT THE VARIOUS MODELS 700 MB LOW TRACKS...THE GFS IS FURTHEST
SOUTH AND QUICKEST...MOVING THE DEVELOPING LOW ACROSS THE NORTHERN
BLACK HILLS AND EAST INTO CENTRAL SD SUNDAY MORNING. THE UKMET IS
SLIGHTLY FURTHER NORTH...WHILE THE NAM...ECMWF...AND SREF TRACK IT
ACROSS FAR SOUTHEASTERN MT LATE TONIGHT AND ALONG THE ND/SD LINE ON
SUNDAY. WITH THE HEAVIEST PCPN TYPICALLY FALLING JUST TO THE NORTH
OF THE 700 MB LOW...THESE SOLUTIONS WOULD GENERALLY FAVOR THE
HEAVIEST SNOWFALL ACROSS FAR NORTHWESTERN SD AND ESPECIALLY PORTIONS
OF NORTHEASTERN MT THROUGH MUCH OF ND. THIS LEAVES CURRENT FORECAST
IN PRETTY GOOD SHAPE...WITH FAR NORTHWESTERN SD LIKELY SEEING THE
HEAVIEST SNOWFALL...GENERALLY 3 TO 6 INCHES... OVERNIGHT INTO
SUNDAY. OBVIOUSLY ANY DEVIATION TO THE EXPECTED TRACK WILL AFFECT
PCPN AND SNOWFALL AMOUNTS ACROSS NORTHWESTERN SD AND POSSIBLY FAR
NORTHEASTERN WY.
WILL KEEP WINTER WX HEADLINES AS IS...WITH AN ADVISORY FOR 3 TO 6
INCHES OF SNOW ACROSS HARDING AND PERKINS COUNTIES. HIGHEST AMOUNTS
LIKELY NEAR THE ND BORDER...WITH LOCALLY HIGHER AMOUNTS NOT OUT OF
THE QUESTION. FURTHER SOUTH...UP TO 3 INCHES OR SO IS POSSIBLE AFTER
RAIN CHANGES TO SNOW ACROSS FAR NORTHERN CAMPBELL CO...CROOK
COUNTY...AND INTO BUTTE COUNTY. THE NORTHERN BLACK HILLS AREA WILL
LIKELY SEE SOME UPSLOPE ENHANCED SNOWFALL SUNDAY AFTER UPPER LOW
PASSES EAST OF THE AREA. UP TO 4 INCHES ARE IN THE FORECAST...
HIGHEST OVER THE HIGHER ELEVATIONS AND FAVORED UPSLOPE AREAS. THIS
COULD CHANGE A BIT AS WELL IF THE LOW MOVES A BIT FURTHER NORTH OR
SOUTH OF THE FORECAST TRACK. EVEN FURTHER SOUTH...THE BEST CHANCE
FOR PCPN ACROSS SOUTHERN SD WILL GENERALLY BE TONIGHT WITH THE COLD
FRONT PASSAGE. LITTLE OR NO SNOWFALL IS EXPECTED IN THESE AREAS.
HIGHS ON SUNDAY WILL RANGE FROM THE LOWER 30S ACROSS THE BLACK HILLS
AND FAR NORTHWESTERN SD...TO THE MID 40S OVER FAR SOUTHERN SD.
THE OTHER ISSUE WILL BE GUSTY WINDS ON SUNDAY AFTER FRONT PASSES AND
PRESSURE GRADIENT TIGHTENS. COLD AIR ADVECTION IS RELATIVELY
WEAK...BUT SUFFICIENT TO MIX STRONGER WINDS ALOFT DOWN DURING THE
LATE MORNING AND AFTERNOON HOURS. WILL ISSUE A WIND ADVISORY FOR A
GOOD PORTION OF THE NORTHWEST AND WEST CENTRAL SD PLAINS FOR LATE
SUNDAY MORNING AND AFTERNOON...WHEN WIND GUSTS OF 45 TO 50 MPH ARE
EXPECTED. THE ADVISORY MAY NEED TO BE EXTENDED FURTHER SOUTH AND
EAST INTO SOUTH CENTRAL SD...BUT NOT SURE IF THE WINDS WILL BE QUITE
THAT STRONG RIGHT NOW. WILL LET OVERNIGHT SHIFT HAVE ANOTHER LOOK AT
IT.
THE SYSTEM WILL MOVE OFF TO THE EAST BY SUNDAY EVENING...WITH PCPN
COVERAGE AND WINDS DIMINISHING.
&&
.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 335 PM MDT SAT APR 13 2013
A LONG WAVE TROUGH WILL VERY SLOWLY CROSS THE CENTRAL
CONUS THROUGH NEXT WEEKEND...KEEPING UNSETTLED AND RATHER COOL
CONDITIONS ACROSS THE REGION. A RATHER SIGNIFICANT SHORTWAVE WILL
MOVE FROM THE CNTRL ROCKIES INTO THE CNTRL PLAINS IN THE TUE-WED
TIME FRAME. THIS WILL BRING A GOOD CHANCE OF LIGHT SNOW TO THE
AREA...ESPECIALLY SOUTH OF I-90...ALTHOUGH THE MODELS KEEP THE MORE
SIGNIFICANT PCPN TO OUR SOUTH. A NRN STREAM CLIPPER WILL THEN CROSS
THE NRN PLAINS ON FRI/FRI NIGHT BRINGING ANOTHER CHANCE OF PCPN AND
POSSIBLE UPSLOPE CONDITIONS TO THE NRN BLKHLS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1105 PM MDT SAT APR 13 2013
WIDESPREAD IFR CIGS WILL PERSIST THROUGH SUNDAY MORNING. IFR
VSBY WITH SNOW LIKELY ACROSS PORTIONS OF NORTHEAST WYOMING AND
NORTHWEST SOUTH DAKOTA. GUSTY NORTHWEST WIND WILL DEVELOP ACROSS
WESTERN SOUTH DAKOTA OVERNIGHT AND CONTINUE THROUGH SUNDAY
AFTERNOON. IFR CIGS WILL GRADUALLY BECOME MVFR CIGS SUNDAY
AFTERNOON.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY FROM 3 AM TO 6 PM MDT SUNDAY FOR SDZ012-013-026-
030-031-072-073.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT SUNDAY FOR SDZ001-002.
WY...NONE.
&&
$$
UPDATE...7
SHORT TERM...26
LONG TERM...10
AVIATION...7
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1153 PM CDT SAT APR 13 2013
.AVIATION...
LOW LEVEL SOUTHERLY FLOW STILL MAY BE CAPABLE OF PATCHY STRATUS
TOWARDS DAYBREAK NEAR KLBB...THOUGH SIGNALS ARE NOT STRONG IN
LATEST GUIDANCE. RETAINED A TEMPO GROUP WITH SCATTERED 1000 FOOT
LAYER TO INDICATE THAT POSSIBILITY. OTHERWISE...LOW LEVEL FLOW
WILL VEER FAIRLY SHARPLY TO THE WEST BY MID MORNING SUNDAY WITH
SURFACE TROUGH AND DRY-LINE EDGING MAINLY EAST OF THE AREA. MODEST
WESTERLY FLOW ALOFT SHOULD LEAD TO SOLID LOW-END WINDY DAY BOTH
TAF SITES WITH VFR CONDITIONS DOMINATING. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 909 PM CDT SAT APR 13 2013/
UPDATE...
THUNDER CHANCES HAVE ENDED FOR THE EVENING. QUICK UPDATE. RMCQUEEN
PREV DISCUSSION... /ISSUED 736 PM CDT SAT APR 13 2013/
UPDATE...
HIGH-BASED THUNDER CHANCES WILL REMAIN BEST IN THE ZONE FROM JUST
NORTH OF MORTON THROUGH LITTLEFIELD AND OLTON TO KRESS FOR THE
NEXT HOUR OR TWO. WE STILL EXPECT ACTIVITY TO DIMINISH AFTER
SUNSET. UPDATED FOR SLIGHTLY FURTHER EAST EXPANSION OF THUNDER
CHANCES AND FOR BETTER COVERAGE OF GUSTY-WIND PRODUCING THUNDER IN
THE FAVORED ZONE INDICATED ABOVE. RMCQUEEN
AVIATION...
NO SIGNIFICANT CHANGES FROM THE PREVIOUS FORECAST. THUNDER CHANCES
THIS EVENING WILL DRIFT NEAR ENOUGH KLBB TO MENTION CUMULONIMBUS
AS THE LOW CLOUD TYPE...BUT DO NOT EXPECT TO MOVE THROUGH KLBB.
A LOW CLOUD LAYER NEAR IFR/MVFR BOUNDARY IS STILL POSSIBLE NEAR
KLBB BRIEFLY NEAR DAYBREAK ON SUNDAY BEFORE THE DRY WESTERLY
COMPONENT WINDS SET IN. VFR SHOULD CONTINUE AT KCDS THROUGH THE
PERIOD. RMCQUEEN
PREV DISCUSSION... /ISSUED 252 PM CDT SAT APR 13 2013/
SHORT TERM...
WEST TEXAS WILL REMAIN UNDER BROAD CYCLONIC FLOW OVER THE SHORT TERM
AS A STORM SYSTEM DIGS THROUGH THE NORTHWESTERN TIER OF THE NATION
AND EMERGES AND STRENGTHENS OVER THE NORTHERN PLAINS SUNDAY. WITHIN
THIS FLOW...A TROUGH AXIS WAS APPROACHING WEST TEXAS AND WILL PASS
TO THE EAST TONIGHT...THOUGH THE BULK OF THE LARGE-SCALE ASCENT WITH
THIS FEATURE WILL EMERGE WELL TO THE SOUTH OF THE FA. EVEN
SO...NORTHERN AND WESTERN SECTIONS OF THE CWA WILL SEE THE
POSSIBILITY OF ISOLATED CONVECTION LATE THIS AFTERNOON THROUGH EARLY
THIS EVENING. LOW-LEVEL MOISTURE IS RATHER LIMITED...WITH DEWPOINTS
ONLY IN THE 30S TO LOWER 40S ACROSS THE CAPROCK...BUT STEEP
MID-LEVEL LAPSE RATES WERE RESULTING IN AROUND 500 J/KG OF SBCAPE
WHILE CIN WAS WEAKENING AND SHOULD BE MINIMAL BY LATE AFTERNOON.
THESE FACTORS COMBINED WITH WEAK CONVERGENCE WERE ALREADY RESULTING
IN A DEVELOPING CUMULUS FIELD FROM NORTH OF HEREFORD TO WEST OF
CLOVIS AS OF 19Z. THE LATEST TTU-WRF...RAP...NAM AND SEVERAL SREF
MEMBERS SUGGEST THAT ISOLATED TO WIDELY SCATTERED CONVECTION WILL
DEVELOP THROUGH MID TO LATE AFTERNOON AND MOVE EASTWARD. EXPECT ANY
ACTIVITY TO QUICKLY WANE THIS EVENING THOUGH THE LATEST RAP AND HRRR
SUGGEST THE ACTIVITY COULD HANG ON AND PASS ACROSS MUCH OF THE SOUTH
PLAINS THIS EVENING. NOT AS CONVINCED OF THIS AND HAVE MAINTAINED
THE ISOLATED THUNDER MENTION GENERALLY ALONG AND WEST OF A MEMPHIS
TO LEVELLAND LINE. RATHER WEAK INSTABILITY...FORCING AND DEEP LAYER
SHEAR SHOULD LIMIT THE STORM ORGANIZATION AND COVERAGE THOUGH
RELATIVELY DRY SUB-CLOUD LAYER /WITH SFC T/TD SPREADS OF 30 TO 40
DEGREES/ COULD SUPPORT LOCALIZED STRONG WIND GUSTS.
A STRONG LLJ WILL THEN DEVELOP ACROSS THE CENTRAL PLAINS TONIGHT
WITH THE SOUTHERN EXTENT OF IT EXTENDING OVER NORTHWEST TEXAS. THIS
JET WILL DRAW BETTER MOISTURE NORTHWARD...WITH MOISTURE ADVECTION
MAXIMIZED ACROSS THE SOUTHWEST ZONES WHERE LOW CLOUDS AND FOG COULD
DEVELOP. BREEZY AND QUICKLY VEERING WINDS TOWARD MORNING SHOULD
LIMIT THE FOG POTENTIAL AND HAVE NOT INCLUDED IN THE GRIDS ATTM.
THIS FLOW WILL ALSO PROVIDE A MILD NIGHT...WITH LOWS IN THE UPPER
40S AND LOWER 50S COMMON. A DRYLINE WILL TIGHTEN TONIGHT IN EASTERN
NM...BUT THE SFC FLOW WILL QUICKLY VEER WESTERLY EARLY SUNDAY AS THE
NORTHERN STORM SYSTEM SHIFTS EASTWARD AND THIS WILL CAUSE THE
DRYLINE TO RACE EASTWARD ACROSS THE SOUTH PLAINS SUNDAY MORNING AND
CLEAR EAST OF THE FA BY MID-AFTERNOON. GUSTY WESTERLY WINDS
SUSTAINED AT 20-25 MPH WILL BE COMMON AND THIS WILL PROPEL HIGHS
WELL INTO THE 80S...WITH EVEN A FEW LOWER 90S POSSIBLE OFF THE
CAPROCK. THESE WARM...DRY AND GUSTY CONDITIONS WILL ALSO CREATE
ELEVATED TO CRITICAL FIRE WEATHER.
LONG TERM...
MAIN INTEREST CONTINUES TO BE UPPER TROUGH AND FRONTAL PASSAGE MID
WEEK AND MODEL INCONSISTENCIES IN HANDLING BOTH FEATURES. 12Z GFS
CAME IN ABOUT 18-24 HOURS SLOWER THAN ITS 00Z RUN AND IS NOW
SLOWER THAN EITHER THE 00Z OR 12Z RUNS OF THE ECMWF. GOOD
CONSISTENCY IN THE ECMWF WILL MAKE IT THE WINNER TODAY...AND GIVEN
THAT THE PREVIOUS FCST TRENDED TOWARD IT...FEW CHANGES WILL BE
MADE TO THAT PART OF THE FCST. IN GENERAL...COOLING TEMPS
WEDNESDAY...THE MAGNITUDE OF WHICH STILL IN DOUBT GIVEN IMPORTANCE
OF FRONTAL TIMING ON THAT ELEMENT. SMALL PRECIP CHANCES CONTINUE
TO FAVOR THE ROLLING PLAINS WHERE SOME LOW LEVEL MOISTURE MAY BE
IN PLACE.
EARLY WEEK WILL CONTINUE TO EXPECT A WEAK FRONTAL BOUNDARY IN OR
NEAR THE NERN PART OF THE FCST AREA THAT SHOULD RESULT IN SLIGHTLY
COOLER TEMPS THERE. LACK OF LOW LEVEL MOISTURE MONDAY SHOULD LIMIT
POPS WHILE BETTER MOISTURE RETURN TUESDAY MAY HELP FUEL ISOLATED
THUNDER. WEST OF THE BOUNDARY...BREEZY AND WARM WITH POSSIBILITY
OF ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS DEVELOPING.
LATTER PART OF THE WEEK LOOKS FAIR AND COOL IN POST-FRONTAL AIR
MASS AND NWLY FLOW ALOFT.
FIRE WEATHER...
THE SOUTH PLAINS REGION WILL SEE GOOD TO EXCELLENT RH RECOVERIES
TONIGHT AS SOUTHERLY FLOW DRAWS IN IMPROVING AMOUNTS OF MOISTURE.
HOWEVER...THIS MOISTURE WILL BE SHUNTED EASTWARD AS A DRYLINE
QUICKLY ADVANCES FROM EASTERN NM /EARLY SUNDAY MORNING/ INTO
SOUTHWEST OK AND WESTERN NORTH TEXAS BY LATE IN THE DAY. RH VALUES
WILL DROP TO 5 TO 10 PERCENT ACROSS THE FA /BEHIND THE DRYLINE/
WHILE TEMPERATURES CLIMB TO 10 TO 15 DEGREES ABOVE AVERAGE.
ADDITIONALLY...SOUTHWEST TO WESTERLY WINDS WILL BECOME SUSTAINED AT
15-25 MPH BEHIND THE DRYLINE DURING THE AFTERNOON...RESULTING IN A
PERIOD OF ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS. HENCE...HAVE
ISSUED A FIRE WEATHER WATCH FOR THE ENTIRE AREA VALID FROM 17-01Z
SUNDAY. EXPECT THE STRONGEST WINDS TO BE ON THE CAPROCK WHERE
LOW-END CRITICAL CONDITIONS /AT LEAST WITH REGARDS TO THE WINDS/
WILL BE MOST LIKELY TO OCCUR FOR THE REQUIRED 3 HOURS OR MORE. IT IS
LESS CERTAIN THAT SPOTS OFF THE CAPROCK WILL OBTAIN MORE THAN
SPOTTY/BRIEF CRITICAL CONDITIONS...BUT HAVE DECIDED TO INCLUDE IN
THE WATCH AND WILL LET THE OVERNIGHT SHIFT DECIDE IF A FIRE DANGER
STATEMENT MAY BE MORE APPROPRIATE.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 44 81 43 80 48 / 20 0 0 0 0
TULIA 49 84 44 82 47 / 30 0 0 0 0
PLAINVIEW 51 85 44 83 50 / 30 0 0 0 0
LEVELLAND 52 85 47 84 49 / 20 0 0 0 0
LUBBOCK 53 87 48 85 52 / 10 0 0 0 0
DENVER CITY 52 85 51 85 51 / 20 0 0 0 0
BROWNFIELD 52 87 49 85 49 / 10 0 0 0 0
CHILDRESS 52 89 48 81 54 / 10 0 0 0 10
SPUR 51 90 50 89 54 / 10 0 0 0 10
ASPERMONT 54 92 53 93 57 / 10 0 0 0 10
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM SUNDAY AFTERNOON THROUGH SUNDAY EVENING
FOR THE FOLLOWING ZONES: TXZ021>044.
&&
$$
99/99/05
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
621 PM CDT MON APR 15 2013
UPDATED AVIATION PORTION FOR 00Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 310 PM CDT MON APR 15 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED LOW
PRESSURE SPINNING OVER NORTHERN MINNESOTA AND THE OCCLUDED/COLD
FRONT NOW OVER FAR EASTERN WISCONSIN EARLY THIS AFTERNOON. AN AREA
OF LIGHT RAIN IS SPREADING NE INTO SW WISCONSIN WITHIN A FGEN BAND
BEHIND THE COLD FRONT. THIS BAND OF RAIN LOOKS TO BE A LITTLE
FARTHER NW THAN WHAT MODELS INDICATE...AND HAVE NOW INCREASED POPS
TO LIKELY OVER EAST-CENTRAL WISCONSIN LATE THIS AFTERNOON INTO THIS
EVENING. MEANWHILE...PLENTY OF LOW STRATUS IS MOVING EAST OVER
NORTHWEST WISCONSIN AND IS NOW MOVING INTO NORTH-CENTRAL WISCONSIN.
NO SIGN OF ANY PRECIPITATION OUT OF THESE CLOUDS SO FAR...AND WILL
GO WITH A DRY FORECAST. PRECIP TRENDS AND TEMPS ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE NORTHEAST FROM NORTHERN
MINNESOTA TO SOUTHERN ONTARIO WHILE THE COLD FRONT WILL SLOWLY SAG
SE ACROSS SOUTHERN LOWER MICHIGAN AND CENTRAL ILLINOIS. NORTH OF
THE FRONT...MODERATE MID-LEVEL FGEN WILL HAVE AN ONGOING BAND OF
LIGHT RAIN IMPACTING SOUTHEAST WISCONSIN. THE LATEST HI-RES MODEL
RUNS SHOW THE NORTHERN EDGE OF THIS LIGHT RAIN JUST CLIPPING
EAST-CENTRAL WISCONSIN THIS EVENING BEFORE PUSHING SOUTHEAST
OVERNIGHT. BUT RADAR TRENDS INDICATE THAT LIGHT RAIN IS LIKELY FROM
OSHKOSH TO KEWAUNEE THIS EVENING. HAVE INCREASED POPS ACCORDINGLY.
IN CLOSER PROXIMITY TO THE LOW PRESSURE...PLENTY OF LOW CLOUDS WILL
MOVE NE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. THESE
CLOUDS MAY RETREAT A LITTLE TO THE NORTH AS THE LOW PULLS AWAY SO
WILL GO WITH MOSTLY CLOUDY CONDITIONS FOR MUCH OF THE NIGHT. WHERE
SKIES DO CLEAR LATE TONIGHT OVER NE WISCONSIN LATE...A FAIRLY TIGHT
PRESSURE GRADIENT WILL PREVENT WINDS FROM DECOUPLING...SO SHOULD SEE
A SEASONABLE NIGHT. LOWS IN THE UPPER 20S NORTH AND WEST...TO THE
MIDDLE 30S NEAR LAKE MICHIGAN.
TUESDAY...THE COLD FRONT WILL SHIFT SOUTH INTO THE OHIO VALLEY WHILE
LOW PRESSURE WILL CONTINUE TO MARCH AWAY INTO QUEBEC. WEAK HIGH
PRESSURE RIDGE AXIS WILL SLIDE EAST INTO THE WESTERN GREAT
LAKES...BUT NORTHWEST WINDS WILL PUSH IN SLIGHTLY COLDER AIR THAN
WHATS PRESENT ACROSS THE REGION TODAY. THERMAL TROUGHING WILL LEAD
TO MORE CLOUDS ACROSS THE NORTHERN WISCONSIN THAN CENTRAL PORTIONS
OF THE STATE SO WILL GO WITH PARTLY TO MOSTLY CLOUDY WORDING. HIGHS
FALLING BACK TO AROUND 40 DEGREES NORTH TO AROUND 50 SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 310 PM CDT MON APR 15 2013
MAIN CHALLENGE THIS FORECAST PERIOD ARE THE TWO SURFACE LOWS
MOVING THROUGH IN RAPID SUCCESSION WEDNESDAY NIGHT AND THURSDAY
NIGHT. THE FIRST ONE HAS LITTLE COLD AIR TO WORK WITH AND SHOULD
BE LARGELY RAIN. THE EXCEPTION WOULD BE IN THE FAR NORTH WHERE
THERE MAY BE AN INCH OR TWO OF WET SNOW OR MIXED PRECIPITATION.
THE SECOND SYSTEM IS MORE INTERESTING AS THE MODELS DEEPEN IT
RATHER QUICKLY (7 TO 10 MB IN 12 HOURS) WHICH WILL RESULT IN
DYNAMIC COOLING AND PRODUCE ENOUGH COLD AIR FOR THE MUCH OF THE
PRECIPITATION TO FALL AS SNOW LATE THURSDAY NIGHT AND FRIDAY. THE
ECMWF IS THE COLDEST OF THE MODELS AND WOULD PRODUCE AT LEAST AN
ADVISORY TYPE SNOW FOR MUCH OF THE FORECAST AREA. THIS SCENARIO IS
CERTAINLY NOT A SURE THING THAT FAR OUT BUT WITH ANOTHER BIG
ARCTIC HIGH CENTERED NORTH OF THE GREAT LAKES AND WARM HUMID AIR
TO OUR SOUTH THERE SHOULD BE A DYNAMIC WEATHER SYSTEM. AFTER THAT
SYSTEM DEPARTS SOME COLD AIR MOVES INTO THE REGION FOR FRIDAY
NIGHT AND SATURDAY. TEMPERATURES MODERATE SUNDAY WITH ANOTHER
WEATHER SYSTEM EARLY NEXT WEEK. &&
.AVIATION...FOR 00Z TAF ISSUANCE
ISSUED AT 611 PM CDT MON APR 15 2013
PCPN WAS DISSIPATING OVER EC WI EARLY THIS EVG...AND WILL NOT
AFFECT ANY OF THE TAF SITES. STRATOCUMULUS MOVG INTO THE AREA IN
THE WAKE OF A COLD FRONT WILL AFFECT MAINLY NC/FAR NE WI OVERNIGHT.
ALTHOUGH CIGS WILL INITIALLY BE LOW VFR AT RHI/AUW/CWA...EXPECT THAT
THEY WILL GRADUALLY LOWER TO MVFR LATER THIS EVG AND OVERNIGHT. ASIDE
FROM SOME LINGERING MVFR CIGS OVER NC WI EARLY IN THE DAY...ANTICIPATE
VFR CONDITIONS TO PREVAIL ON TUESDAY. DAYTIME MIXING WILL CAUSE WEST
WINDS TO INCREASE BY LATE MORNING...BUT GUSTS SHOULD ONLY BE AROUND
20 KTS.
&&
.HYDROLOGY...
ISSUED AT 310 PM CDT MON APR 15 2013
WARMER TEMPERATURES TODAY HAVE INCREASED SNOW/ICE MELT. THIS AND
RUNOFF FROM LAST NIGHT`S PCPN WILL BRING SOME RISES ON AREA RIVERS
AND STREAMS. WILL NEED TO MONITOR THE HYDRO SITUATION DURING THE
MID TO LATE PART OF THE WEEK...AS A COUPLE LOW PRESSURE SYSTEMS
ARE EXPECTED TO BRING SIGNIFICANT PCPN FROM WEDS NGT THROUGH FRIDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC/KIECKBUSCH
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 310 PM CDT MON APR 15 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED LOW
PRESSURE SPINNING OVER NORTHERN MINNESOTA AND THE OCCLUDED/COLD
FRONT NOW OVER FAR EASTERN WISCONSIN EARLY THIS AFTERNOON. AN AREA
OF LIGHT RAIN IS SPREADING NE INTO SW WISCONSIN WITHIN A FGEN BAND
BEHIND THE COLD FRONT. THIS BAND OF RAIN LOOKS TO BE A LITTLE
FARTHER NW THAN WHAT MODELS INDICATE...AND HAVE NOW INCREASED POPS
TO LIKELY OVER EAST-CENTRAL WISCONSIN LATE THIS AFTERNOON INTO THIS
EVENING. MEANWHILE...PLENTY OF LOW STRATUS IS MOVING EAST OVER
NORTHWEST WISCONSIN AND IS NOW MOVING INTO NORTH-CENTRAL WISCONSIN.
NO SIGN OF ANY PRECIPITATION OUT OF THESE CLOUDS SO FAR...AND WILL
GO WITH A DRY FORECAST. PRECIP TRENDS AND TEMPS ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE NORTHEAST FROM NORTHERN
MINNESOTA TO SOUTHERN ONTARIO WHILE THE COLD FRONT WILL SLOWLY SAG
SE ACROSS SOUTHERN LOWER MICHIGAN AND CENTRAL ILLINOIS. NORTH OF
THE FRONT...MODERATE MID-LEVEL FGEN WILL HAVE AN ONGOING BAND OF
LIGHT RAIN IMPACTING SOUTHEAST WISCONSIN. THE LATEST HI-RES MODEL
RUNS SHOW THE NORTHERN EDGE OF THIS LIGHT RAIN JUST CLIPPING
EAST-CENTRAL WISCONSIN THIS EVENING BEFORE PUSHING SOUTHEAST
OVERNIGHT. BUT RADAR TRENDS INDICATE THAT LIGHT RAIN IS LIKELY FROM
OSHKOSH TO KEWAUNEE THIS EVENING. HAVE INCREASED POPS ACCORDINGLY.
IN CLOSER PROXIMITY TO THE LOW PRESSURE...PLENTY OF LOW CLOUDS WILL
MOVE NE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. THESE
CLOUDS MAY RETREAT A LITTLE TO THE NORTH AS THE LOW PULLS AWAY SO
WILL GO WITH MOSTLY CLOUDY CONDITIONS FOR MUCH OF THE NIGHT. WHERE
SKIES DO CLEAR LATE TONIGHT OVER NE WISCONSIN LATE...A FAIRLY TIGHT
PRESSURE GRADIENT WILL PREVENT WINDS FROM DECOUPLING...SO SHOULD SEE
A SEASONABLE NIGHT. LOWS IN THE UPPER 20S NORTH AND WEST...TO THE
MIDDLE 30S NEAR LAKE MICHIGAN.
TUESDAY...THE COLD FRONT WILL SHIFT SOUTH INTO THE OHIO VALLEY WHILE
LOW PRESSURE WILL CONTINUE TO MARCH AWAY INTO QUEBEC. WEAK HIGH
PRESSURE RIDGE AXIS WILL SLIDE EAST INTO THE WESTERN GREAT
LAKES...BUT NORTHWEST WINDS WILL PUSH IN SLIGHTLY COLDER AIR THAN
WHATS PRESENT ACROSS THE REGION TODAY. THERMAL TROUGHING WILL LEAD
TO MORE CLOUDS ACROSS THE NORTHERN WISCONSIN THAN CENTRAL PORTIONS
OF THE STATE SO WILL GO WITH PARTLY TO MOSTLY CLOUDY WORDING. HIGHS
FALLING BACK TO AROUND 40 DEGREES NORTH TO AROUND 50 SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 310 PM CDT MON APR 15 2013
MAIN CHALLENGE THIS FORECAST PERIOD ARE THE TWO SURFACE LOWS
MOVING THROUGH IN RAPID SUCCESSION WEDNESDAY NIGHT AND THURSDAY
NIGHT. THE FIRST ONE HAS LITTLE COLD AIR TO WORK WITH AND SHOULD
BE LARGELY RAIN. THE EXCEPTION WOULD BE IN THE FAR NORTH WHERE
THERE MAY BE AN INCH OR TWO OF WET SNOW OR MIXED PRECIPITATION.
THE SECOND SYSTEM IS MORE INTERESTING AS THE MODELS DEEPEN IT
RATHER QUICKLY (7 TO 10 MB IN 12 HOURS) WHICH WILL RESULT IN
DYNAMIC COOLING AND PRODUCE ENOUGH COLD AIR FOR THE MUCH OF THE
PRECIPITATION TO FALL AS SNOW LATE THURSDAY NIGHT AND FRIDAY. THE
ECMWF IS THE COLDEST OF THE MODELS AND WOULD PRODUCE AT ;EAST AN
ADVISORY TYPE SNOW FOR MUCH OF THE FORECAST AREA. THIS SCENARIO IS
CERTAINLY NOT A SURE THING THAT FAR OUT BUT WITH ANOTHER BIG
ARCTIC HIGH CENTERED NORTH OF THE GREAT LAKES AND WARM HUMID AIR
TO OUR SOUTH THERE SHOULD BE A DYNAMIC WEATHER SYSTEM. AFTER THAT
SYSTEM DEPARTS SOME COLD AIR MOVES INTO THE REGION FOR FRIDAY
NIGHT AND SATURDAY. TEMPERATURES MODERATE SUNDAY WITH ANOTHER
WEATHER SYSTEM EARLY NEXT WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1224 PM CDT MON APR 15 2013
LOW PRESSURE WILL TRACK NORTHEAST FROM NORTHERN MINNESOTA TO
SOUTHERN ONTARIO DURING THE TAF PERIOD. PLENTY OF MVFR STRATUS ON
THE SOUTHERN FLANK OF THIS LOW HOWEVER...WHICH WILL LIKELY MOVE
INTO CENTRAL AND NORTHERN WISCONSIN LATER THIS AFTERNOON AND
TONIGHT. STRATUS WILL LIKELY BE VFR WHEN IT ARRIVES...BUT THEN
LOWER OVERNIGHT. AN AREA OF LIGHT RAIN SHOWERS OVER IOWA WILL MOVE
NORTHEAST INTO EAST-CENTRAL WISCONSIN LATE THIS AFTERNOON INTO
THIS EVENING. LATEST MODEL GUIDANCE INDICATES THAT THE SHOWERS
WILL REMAIN SOUTH OF THE FOX VALLEY TAF SITES...SO WILL MAINTAIN
VFR CONDITIONS OVER EAST-CENTRAL AND NORTHEAST WISCONSIN THROUGH
THE TAF PERIOD. GUSTY SOUTHWEST WINDS WILL DIMINISH THIS EVENING.
&&
.HYDROLOGY...
ISSUED AT 310 PM CDT MON APR 15 2013
WARMER TEMPERATURES TODAY WILL INCREASE
SNOW/ICE MELT. THIS AND PCPN OVERNIGHT WILL BRING SOME RISES ON
AREA RIVERS AND STREAMS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC
HYDROLOGY......MPC
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND MONDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW ELONGATED LOW
PRESSURE SPINNING ALONG THE IOWA/NEBRASKA BORDER THIS
AFTERNOON...AND A SURFACE WARM FRONT EXTENDING EASTWARD ACROSS
NORTHERN ILLINOIS. SOUTH OF THE WARM FRONT...TEMPERATURES ARE IN
THE 60S AND 70S. BUT NORTH OF THE FRONT...A 50KT SSW LLJ IS LEADING TO
A BAND OF PRECIPITATION WHICH IS NOW PUSHING INTO THE NORTHERN
SECTIONS OF THE BADGER STATE. TEMPERATURES REMAIN IN THE 20S AND
30S WITHIN THIS BAND OF PRECIP...WHERE LOCATIONS OVER CENTRAL
WISCONSIN HAVE PICKED UP A QUICK 2-3 INCHES OF WET SNOW. A FEW
SPOTTER REPORTS HAVE CONFIRMED WHAT DUAL POL IS SHOWING...THAT SNOW
IS MIXING WITH RAIN AND SLEET...WITH THE CHANGE OVER NOW SPREADING
INTO SOUTHERN MARATHON AND SHAWANO COUNTIES. ADDITIONALLY...SURFACE
WET BULB ZERO TEMPS ARE SPREADING NORTHEAST INTO EAST-CENTRAL
WISCONSIN...SO SHOULDNT SEE TOO MUCH MORE ACCUMS IN THESE AREAS.
STILL EXPECTING THE MODERATE TO HEAVY SNOW TO SPREAD INTO
NORTH-CENTRAL WISCONSIN THIS AFTERNOON WHERE A QUICK 3 INCHES WILL
LIKELY FALL. WILL CONTINUE TO HANDLE THE SNOWFALL WITH SPS
UPDATES. PRECIP CONTINUES TO BE THE MAIN FORECAST CONCERN FOR THIS
FORECAST.
TONIGHT...LOW PRESSURE WILL OCCLUDE AS IT LIFTS NORTH OVER SOUTHERN
MINNESOTA...WHILE THE OCCLUDED/COLD FRONT WILL SWEEP ACROSS THE AREA
LATE THIS EVENING AND THROUGH THE OVERNIGHT HOURS. SNOW/SLEET LOOK
TO BE ONGOING OVER NORTH-CENTRAL WISCONSIN AT THE START OF THE
EVENING WHILE CONDITIONS LOOK TO BE DRY FOR A PERIOD OVER
EAST-CENTRAL AND POSSIBLY FAR NORTHEAST WISCONSIN. THIS DRY PERIOD
OVER THE EAST WILL BE SHORT-LIVED HOWEVER...AS A BAND OF SHOWERS AND
EMBEDDED THUNDERSTORMS WILL MOVE THROUGH ALONG THE OCCLUDED/COLD
FRONT. PROGGED SOUNDINGS INDICATE THAT PTYPE SHOULD BE MAINLY RAIN
ACROSS THE REGION BY THE TIME THIS BAND ARRIVES...WHICH WILL LOOK TO
DUMP AROUND 0.75 INCHES OF RAIN OVER WESTERN SECTIONS OF THE CWA.
AMOUNTS SHOULD DROP OFF TO THE EAST AS INSTABILITY IS LOST THROUGH
THE NIGHT. BEST CHANCES OF THUNDER LOOK TO OCCUR OVER CENTRAL AND
EAST-CENTRAL AND WILL KEEP IT IN THE FORECAST. TEMPERATURES WILL
LIKELY PEAK LATE IN THE EVENING OR EARLY OVERNIGHT...JUST AHEAD OF
THE FRONT. LOWS IN THE 30S AND 40S.
MONDAY...OCCLUDED LOW PRESSURE WILL LIFT NE ACROSS NORTHERN
MINNESOTA. PRECIP WILL HAVE EXITED ALONG THE FRONT BY THE START OF
THE PERIOD AND SKIES WILL LIKELY TURN MOSTLY CLEAR FOR A PERIOD
DURING THE MORNING. HOWEVER...AS COLDER AIR FILTERS IN FROM THE
WEST AND MID-LEVEL TEMPS COOL...STEEPENING LOW LEVEL LAPSE RATES AND
WRAP AROUND MOISTURE WILL LEAD TO INCREASING CLOUDS FROM LATE
MORNING THROUGH THE REST OF THE DAY. COULD SEE A FEW INSTABILITY
RAIN AND SNOW SHOWERS DEVELOP OVER CENTRAL AND NORTHEAST WISCONSIN
IN THE AFTERNOON. GUSTY SOUTHWEST WINDS WILL BRING IN THE WARMEST
TEMPS THE AREA HAS SEEN IN SOME TIME...AND WILL GO WITH HIGHS
RANGING FROM THE LOW 40S NORTH TO THE MID 50S NEAR LAKE MICHIGAN.
.LONG TERM...MONDAY NIGHT THROUGH SUNDAY
ISSUED AT 304 PM CDT SUN APR 14 2013
FLOOD POTENTIAL IS PROBABLY THE MAIN CHALLENGE FOR THIS FORECAST
PERIOD. THE COLD FRONT MOVES THROUGH MONDAY WITH DRY BUT
SEASONABLE AIR FOLLOWING FOR MONDAY NIGHT THROUGH TUESDAY NIGHT.
SNOW WILL PROBABLY BE GONE OVER MUCH OF THE AREA BELOW 1000 FT
ELEVATION BY THEN WITH THAT SNOW MELT PROBABLY CONTRIBUTING TO
RISES OF THE WOLF RIVER AND SMALL STREAMS OVER EAST CENTRAL
WISCONSIN. MODELS ARE NOW IN GENERAL AGREEMENT WITH SURFACE LOW THAT
MOVES NORTHEAST FROM SOUTHERN PLAINS TO LOWER MICHIGAN WEDNESDAY
THROUGH THURSDAY. LOOKS LIKE THIS WILL BE A LARGELY RAIN EVENT
UNLESS THE STORM TRACKS FURTHER SOUTH. A RAIN EVENT COUPLED BY
SNOW MELT IN THE NORTH WILL LIKELY CAUSE SOME FLOODING OF SMALL
STREAMS AROUND THE AREA BY THURSDAY BUT SIGNIFICANTLY COLDER AND
DRIER AIR WILL SLOW SNOW MELT FRIDAY AND SATURDAY.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1226 PM CDT SUN APR 14 2013
SNOW...MODERATE TO HEAVY AT TIMES...WILL CONTINUE TO
MOVE NORTHEAST ACROSS THE REGION INTO THE AFTERNOON. THE SNOW WILL
CHANGE OVER TO RAIN OVER THE FOX VALLEY AND CENTRAL WISCONSIN AROUND
MID AFTERNOON BUT NOT BEFORE 1-3 INCHES OF ACCUMULATION OCCUR. SNOW
WILL CHANGE OVER TO SLEET AND RAIN OVER NORTHERN WISCONSIN LATE THIS
AFTERNOON OR EARLY THIS EVENING AND ACCUMULATIONS WILL LIKELY REACH
IN THE 2-4 INCH RANGE. THEN A COLD FRONT WILL SWEEP ACROSS THE
REGION TONIGHT. HAVE DELAYED THE TIMING OF THE PRECIPITATION
ASSOCIATED WITH THE FRONT BY A COUPLE HOURS...BUT SHOULD SEE A BAND
OF MODERATE TO HEAVY RAIN PASS ACROSS THE REGION LATE THIS EVENING
INTO THE OVERNIGHT HOURS. THE RAIN WILL PUSH TO THE EAST LATE
TONIGHT AND WILL SEE VFR CONDITIONS RETURN MONDAY MORNING FOR MUCH
OF THE REGION.
&&
.HYDROLOGY...
ISSUED AT 304 PM CDT SUN APR 14 2013
CONTINUED CONCERNS FOR FLOODING ISSUES GIVEN EXPECTED
QPF WITH THE FRONTAL PASSAGE TONIGHT. AN ADDITIONAL THREE QUARTERS
TO AN INCH OF PRECIP MAY FALL OVER CENTRAL AND NORTH-CENTRAL
WISCONSIN BY MONDAY MORNING. WARMER TEMPERATURES TONIGHT AND MONDAY
WILL ADD SNOW MELT INTO THE EQUATIONS. CONCERNS ADDRESSED IN CURRENT
ESF PRODUCT AND RIVER FLOOD STATEMENTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......MPC
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1206 AM CDT TUE APR 16 2013
.UPDATE...
ISSUED AT 1059 PM CDT MON APR 15 2013
LATEST MODEL GUIDANCE...PARTICULARLY THE RAP AND 00Z NAM SUGGEST
THAT THE BAND OF ISENTROPIC ASCENT CURRENTLY FEEDING THUNDERSTORMS
FROM SOUTHEAST KANSAS INTO MISSOURI WILL REMAIN FOCUSED OVER THE
AREA ALREADY SEEING TSTORM ACTIVITY. WHILE A FEW CELLS MAY DEVELOP
TO THE NORTH OF THE MAIN BAND OF ACTIVITY...THERE SEEMS TO BE
LIMITED INSTABILITY TO THE NORTH AND PERHAPS EVEN AN ELEVATED CAP
INHIBITING MORE ROBUST DEVELOPMENT. SO WITH THIS UPDATE HAVE KEPT
MOST THUNDERSTORM CHANCES SOUTH OF I-35 THROUGH AROUND 09Z...AND
USING THIS REASONING HAVE ALSO KEPT THE SEVERE THUNDERSTORM WATCH
SOUTH OF THE LOCAL FORECAST AREA FOR NOW.
HOWEVER...BY 08Z TO 10Z...EXPECT AN AREA OF LOW LEVEL MOISTURE
CURRENTLY EVIDENT OVER CENTRAL AND NORTH CENTRAL OKLAHOMA TO
STREAM NORTH ON THE NOSE OF AN INTENSIFYING LOW LEVEL JET. THIS
WARM MOIST AIRMASS WILL UNDERCUT SLIGHTLY STEEPER MID LEVEL LAPSE
RATES THAT ARE ADVECTING IN FROM SOUTHWEST KANSAS...EVIDENT ON THE
00Z DDC UPPER AIR SOUNDING. AS THIS WARM MOIST ADVECTION BECOMES
DEEP ENOUGH AND ISENTROPIC ASCENT IS ENHANCED WITHIN IT...AGAIN
PROBABLY IN THE 08Z TO 10Z TIME PERIOD...EXPECT SCATTERED
THUNDERSTORMS TO DEVELOP FROM SOUTH CENTRAL KANSAS NORTH INTO THE
EMPORIA AREA...AND EVENTUALLY FARTHER NORTH TOWARD THE I-70
CORRIDOR. MUCAPE INITIALLY SHOULD BE IN THE 400 TO 800 J/KG RANGE
WITH SOME INDICATIONS OF INCREASING CLOSER TO 1000 TO 1500 J/KG
AFTER SUNRISE. EFFECTIVE SHEAR ALOFT WILL BE QUITE STRONG AND WILL
SUPPORT STORM ORGANIZATION. IF THE STRONGER INSTABILITY COMES TO
FRUITION...COULD POTENTIALLY SEE A FEW STORMS PRODUCE SEVERE HAIL
MAINLY ALONG AND SOUTH OF I-70 AND PROBABLY AROUND SUNRISE OR
THEREAFTER. COULD BE A MARGINAL EVENT AS CONVECTIVE INTERACTIONS
MAY MITIGATE STORM STRENGTH. WILL HAVE TO MONITOR THE SITUATION
CLOSELY AS THE EVENING PROGRESSES REGARDING EVENTUAL SEVERE HAIL
POTENTIAL.
TO THE NORTH...AN AREA OF VERY LIGHT RAIN AND SNOW WAS EVIDENT ON
RADAR IN SOUTHERN NEBRASKA. THIS ACTIVITY SHOULD STAY NORTH OF THE
LOCAL FORECAST AREA BUT I SUPPOSE A SPRINKLE OR SNOWFLAKE WOULD
NOT BE COMPLETELY OUT OF THE QUESTION IN FAR NORTH CENTRAL KANSAS.
BARJENBRUCH
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
FRONTAL BOUNDARY REMAINS SOUTH OF KANSAS ACROSS OKLAHOMA NORTHEAST
INTO MISSOURI AT 19Z. SOME CLEARING OF MID LEVEL DECK OCCURRING
ACROSS THE NORTH CENTRAL KANSAS COUNTIES WHILE SOLID OVERCAST
CONTINUES ACROSS EAST CENTRAL KANSAS. THE COMBINATION OF NORTHERLY
WINDS AND CLOUDS HAVE KEPT TEMPERATURES COOLER THAN EARLIER FORECAST
AND MADE ADJUSTMENTS DOWNWARD.
TONIGHT...ISENTROPIC LIFT OVER THE BOUNDARY WILL DEVELOP ELEVATED
SHOWERS AND SOME THUNDERSTORMS ACROSS THE AREA LATER TONIGHT.
PROFILERS ALREADY SHOWING SOUTHERLY 925MB-850MB WINDS IN EASTERN
OKLAHOMA. ISENTROPIC LIFT ON THE 300K SURFACE AND THE 305K SURFACE
INCREASES AFTER 06Z TONIGHT. BETTER ELEVATED INSTABILITY WILL BE
SOUTHEAST OF THE TURNPIKE. ELEVATED CAPE OF ONLY 100-200 J/KG
FORECAST OVERNIGHT. LOWS TONIGHT WILL COOL INTO THE MID 30S NORTH
CENTRAL TO THE MID 40S EAST CENTRAL.
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE MORNING HOURS
THEN DECREASE SOME IN THE AFTERNOON. EML STRENGTHENS TUESDAY
AFTERNOON ACROSS THE AREA. HIGHS TUESDAY WILL ONLY BE IN THE UPPER
40S TO LOWER 50S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
WARM AIR AND MOISTURE ADVECTION WILL DRAMATICALLY INCREASE TUESDAY
NIGHT AS A STRONG LLVL JET DEVELOPS. THIS WILL ESPECIALLY BE THE
CASE IN THE OVERNIGHT HOURS. ELEVATED CAPE WILL INCREASE INTO THE
1200-1800 J/KG RANGE ACROSS MUCH OF THE SOUTH COUNTY WARNING. WITH
DECREASING INHIBITION...EXPECT AT LEAST SCATTERED THUNDERSTORMS TO
DEVELOP WHICH COULD PRODUCE LARGE HAIL THROUGH SUNRISE ACROSS AREAS
GENERALLY ALONG AND SOUTH OF I 70 AS THE WARM FRONT REMAINS
GENERALLY SOUTH OF THE COUNTY WARNING AREA. MODELS SHOW CONSIDERABLE
DIFFERENCES IN THE TIMING OF THE STRONG UPPER LEVEL TROUGH COMING
OUT OF THE ROCKIES BY WEDNESDAY NIGHT AND HOW FAR THE WARM FRONT AND
SFC LOW DEVELOPS/MOVES. HAVE LEANED MORE TOWARDS A MORE SOUTHERLY
TRACK OF THE SFC LOW AND ASSOCIATED WARM FRONT WITH AN INVERTED
TROUGH EXTENDING NORTHEAST FROM THE LOW INTO THE CWA WEDNESDAY. AS
THE FLOW ALOFT INCREASES AND MOISTURE CONTINUES TO SURGE NORTHWARD
AS THE MAIN DYNAMICS OF THE SYSTEM ROTATE OUT INTO THE PLAINS EXPECT
MULTIPLE ROUNDS OF CONVECTION ACROSS MOST OF THE CWA TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...SOME OF WHICH COULD PRODUCE LARGE
HAIL...ALTHOUGH STRONG WINDS WILL ALSO BE POSSIBLE AHEAD OF THE
ADVANCING TROUGH WEDNESDAY AND WEDNESDAY EVENING. LOCALLY HEAVY
RAINFALL AMOUNTS WILL ALSO BE POSSIBLE ESPECIALLY ACROSS THE
SOUTHEAST HALF OF THE CWA. FAVORED THE EC MODEL IN THE OUTER PERIODS
OF THIS SYSTEM AS IT EJECTS OUT INTO THE PLAINS THURSDAY WITH A RAIN
SNOW MIX POSSIBLE IN THE FAR NORTH CENTRAL COUNTIES LATE WEDNESDAY
NIGHT THEN ACROSS THE NORTHWEST HALF THURSDAY AND THE FAR NORTH
THURSDAY EVENING AS COLDER AIR SURGES IN WITHIN THE WRAPAROUND
MOISTURE FIELD ON THE BACKSIDE OF THE DEPARTING SYSTEM. DO NOT HAVE
HIGH ENOUGH CONFIDENCE TO GO ALL SNOW AT THIS POINT IN ANY ONE
LOCATION. THERE WILL BE A LARGE A DIFFICULT TO FORECAST TEMPERATURE
SPREAD ACROSS THE CWA WITH THE FRONT ON WEDNESDAY. FOR NOW WILL GO
WITH THE UPPER 40S NORTH CENTRAL TO NEAR 70 IN THE FAR SOUTHEAST
CORNER. TEMPERATURES WILL THEN FALL INTO THURSDAY WITH HIGHS FROM
THE UPPER 30S NORTH CENTRAL TO THE 40S ELSEWHERE.
THE MODELS ARE STILL IN AGREEMENT THAT AFTER THE DEEP TROUGH PASSES
THROUGH THE AREA THURSDAY...IT SHOULD BE DRY UNTIL THE PASSAGE OF
ANOTHER SHORTWAVE TROUGH OCCURS SUNDAY INTO MONDAY. THIS WILL BE THE
NEXT CHANCE FOR SHOWERS. HIGHS FOLLOWING THE THURSDAY SYSTEM WILL
REMAIN BELOW NORMAL WITH READINGS IN THE UPPER 40S AND LOW 50S
FRIDAY THEN THE 60S FOR SATURDAY INTO MONDAY. FROST AND OR FREEZING
TEMPERATURES REMAIN A CONCERN PRIMARILY FOR FRIDAY AND SATURDAY
MORNINGS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1203 AM CDT TUE APR 16 2013
VFR CONDITIONS ARE EXPECTED THROUGH AROUND 22Z. A WINDOW OF
THUNDERSTORM POTENTIAL EXISTS BETWEEN AROUND 10Z AND 18Z...WITH
BEST CHANCE FOR TS AT FOE/TOP. TS WILL BE SCATTERED IN NATURE AND
NOT PREDOMINANT...AND MAY STAY SOUTH OF TAF SITES SO DID NOT
INCLUDE TSRA IN THE TAF AT THIS TIME. IF STRONG STORMS MOVE
OVERHEAD...HAIL WILL BE POSSIBLE. MVFR CIGS SHOULD BUILD IN BY
LATE AFTERNOON/EVENING.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...53
LONG TERM...63
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1116 PM CDT MON APR 15 2013
...UPDATED FORECAST FOR THUNDERSTORM EXPECTATIONS THROUGH MORNING...
.UPDATE...
ISSUED AT 1059 PM CDT MON APR 15 2013
LATEST MODEL GUIDANCE...PARTICULARLY THE RAP AND 00Z NAM SUGGEST
THAT THE BAND OF ISENTROPIC ASCENT CURRENTLY FEEDING THUNDERSTORMS
FROM SOUTHEAST KANSAS INTO MISSOURI WILL REMAIN FOCUSED OVER THE
AREA ALREADY SEEING TSTORM ACTIVITY. WHILE A FEW CELLS MAY DEVELOP
TO THE NORTH OF THE MAIN BAND OF ACTIVITY...THERE SEEMS TO BE
LIMITED INSTABILITY TO THE NORTH AND PERHAPS EVEN AN ELEVATED CAP
INHIBITING MORE ROBUST DEVELOPMENT. SO WITH THIS UPDATE HAVE KEPT
MOST THUNDERSTORM CHANCES SOUTH OF I-35 THROUGH AROUND 09Z...AND
USING THIS REASONING HAVE ALSO KEPT THE SEVERE THUNDERSTORM WATCH
SOUTH OF THE LOCAL FORECAST AREA FOR NOW.
HOWEVER...BY 08Z TO 10Z...EXPECT AN AREA OF LOW LEVEL MOISTURE
CURRENTLY EVIDENT OVER CENTRAL AND NORTH CENTRAL OKLAHOMA TO
STREAM NORTH ON THE NOSE OF AN INTENSIFYING LOW LEVEL JET. THIS
WARM MOIST AIRMASS WILL UNDERCUT SLIGHTLY STEEPER MID LEVEL LAPSE
RATES THAT ARE ADVECTING IN FROM SOUTHWEST KANSAS...EVIDENT ON THE
00Z DDC UPPER AIR SOUNDING. AS THIS WARM MOIST ADVECTION BECOMES
DEEP ENOUGH AND ISENTROPIC ASCENT IS ENHANCED WITHIN IT...AGAIN
PROBABLY IN THE 08Z TO 10Z TIME PERIOD...EXPECT SCATTERED
THUNDERSTORMS TO DEVELOP FROM SOUTH CENTRAL KANSAS NORTH INTO THE
EMPORIA AREA...AND EVENTUALLY FARTHER NORTH TOWARD THE I-70
CORRIDOR. MUCAPE INITIALLY SHOULD BE IN THE 400 TO 800 J/KG RANGE
WITH SOME INDICATIONS OF INCREASING CLOSER TO 1000 TO 1500 J/KG
AFTER SUNRISE. EFFECTIVE SHEAR ALOFT WILL BE QUITE STRONG AND WILL
SUPPORT STORM ORGANIZATION. IF THE STRONGER INSTABILITY COMES TO
FRUITION...COULD POTENTIALLY SEE A FEW STORMS PRODUCE SEVERE HAIL
MAINLY ALONG AND SOUTH OF I-70 AND PROBABLY AROUND SUNRISE OR
THEREAFTER. COULD BE A MARGINAL EVENT AS CONVECTIVE INTERACTIONS
MAY MITIGATE STORM STRENGTH. WILL HAVE TO MONITOR THE SITUATION
CLOSELY AS THE EVENING PROGRESSES REGARDING EVENTUAL SEVERE HAIL
POTENTIAL.
TO THE NORTH...AN AREA OF VERY LIGHT RAIN AND SNOW WAS EVIDENT ON
RADAR IN SOUTHERN NEBRASKA. THIS ACTIVITY SHOULD STAY NORTH OF THE
LOCAL FORECAST AREA BUT I SUPPOSE A SPRINKLE OR SNOWFLAKE WOULD
NOT BE COMPLETELY OUT OF THE QUESTION IN FAR NORTH CENTRAL KANSAS.
BARJENBRUCH
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
FRONTAL BOUNDARY REMAINS SOUTH OF KANSAS ACROSS OKLAHOMA NORTHEAST
INTO MISSOURI AT 19Z. SOME CLEARING OF MID LEVEL DECK OCCURRING
ACROSS THE NORTH CENTRAL KANSAS COUNTIES WHILE SOLID OVERCAST
CONTINUES ACROSS EAST CENTRAL KANSAS. THE COMBINATION OF NORTHERLY
WINDS AND CLOUDS HAVE KEPT TEMPERATURES COOLER THAN EARLIER FORECAST
AND MADE ADJUSTMENTS DOWNWARD.
TONIGHT...ISENTROPIC LIFT OVER THE BOUNDARY WILL DEVELOP ELEVATED
SHOWERS AND SOME THUNDERSTORMS ACROSS THE AREA LATER TONIGHT.
PROFILERS ALREADY SHOWING SOUTHERLY 925MB-850MB WINDS IN EASTERN
OKLAHOMA. ISENTROPIC LIFT ON THE 300K SURFACE AND THE 305K SURFACE
INCREASES AFTER 06Z TONIGHT. BETTER ELEVATED INSTABILITY WILL BE
SOUTHEAST OF THE TURNPIKE. ELEVATED CAPE OF ONLY 100-200 J/KG
FORECAST OVERNIGHT. LOWS TONIGHT WILL COOL INTO THE MID 30S NORTH
CENTRAL TO THE MID 40S EAST CENTRAL.
SHOWERS AND THUNDERSTORMS WILL CONTINUE THROUGH THE MORNING HOURS
THEN DECREASE SOME IN THE AFTERNOON. EML STRENGTHENS TUESDAY
AFTERNOON ACROSS THE AREA. HIGHS TUESDAY WILL ONLY BE IN THE UPPER
40S TO LOWER 50S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 359 PM CDT MON APR 15 2013
WARM AIR AND MOISTURE ADVECTION WILL DRAMATICALLY INCREASE TUESDAY
NIGHT AS A STRONG LLVL JET DEVELOPS. THIS WILL ESPECIALLY BE THE
CASE IN THE OVERNIGHT HOURS. ELEVATED CAPE WILL INCREASE INTO THE
1200-1800 J/KG RANGE ACROSS MUCH OF THE SOUTH COUNTY WARNING. WITH
DECREASING INHIBITION...EXPECT AT LEAST SCATTERED THUNDERSTORMS TO
DEVELOP WHICH COULD PRODUCE LARGE HAIL THROUGH SUNRISE ACROSS AREAS
GENERALLY ALONG AND SOUTH OF I 70 AS THE WARM FRONT REMAINS
GENERALLY SOUTH OF THE COUNTY WARNING AREA. MODELS SHOW CONSIDERABLE
DIFFERENCES IN THE TIMING OF THE STRONG UPPER LEVEL TROUGH COMING
OUT OF THE ROCKIES BY WEDNESDAY NIGHT AND HOW FAR THE WARM FRONT AND
SFC LOW DEVELOPS/MOVES. HAVE LEANED MORE TOWARDS A MORE SOUTHERLY
TRACK OF THE SFC LOW AND ASSOCIATED WARM FRONT WITH AN INVERTED
TROUGH EXTENDING NORTHEAST FROM THE LOW INTO THE CWA WEDNESDAY. AS
THE FLOW ALOFT INCREASES AND MOISTURE CONTINUES TO SURGE NORTHWARD
AS THE MAIN DYNAMICS OF THE SYSTEM ROTATE OUT INTO THE PLAINS EXPECT
MULTIPLE ROUNDS OF CONVECTION ACROSS MOST OF THE CWA TUESDAY NIGHT
THROUGH WEDNESDAY NIGHT...SOME OF WHICH COULD PRODUCE LARGE
HAIL...ALTHOUGH STRONG WINDS WILL ALSO BE POSSIBLE AHEAD OF THE
ADVANCING TROUGH WEDNESDAY AND WEDNESDAY EVENING. LOCALLY HEAVY
RAINFALL AMOUNTS WILL ALSO BE POSSIBLE ESPECIALLY ACROSS THE
SOUTHEAST HALF OF THE CWA. FAVORED THE EC MODEL IN THE OUTER PERIODS
OF THIS SYSTEM AS IT EJECTS OUT INTO THE PLAINS THURSDAY WITH A RAIN
SNOW MIX POSSIBLE IN THE FAR NORTH CENTRAL COUNTIES LATE WEDNESDAY
NIGHT THEN ACROSS THE NORTHWEST HALF THURSDAY AND THE FAR NORTH
THURSDAY EVENING AS COLDER AIR SURGES IN WITHIN THE WRAPAROUND
MOISTURE FIELD ON THE BACKSIDE OF THE DEPARTING SYSTEM. DO NOT HAVE
HIGH ENOUGH CONFIDENCE TO GO ALL SNOW AT THIS POINT IN ANY ONE
LOCATION. THERE WILL BE A LARGE A DIFFICULT TO FORECAST TEMPERATURE
SPREAD ACROSS THE CWA WITH THE FRONT ON WEDNESDAY. FOR NOW WILL GO
WITH THE UPPER 40S NORTH CENTRAL TO NEAR 70 IN THE FAR SOUTHEAST
CORNER. TEMPERATURES WILL THEN FALL INTO THURSDAY WITH HIGHS FROM
THE UPPER 30S NORTH CENTRAL TO THE 40S ELSEWHERE.
THE MODELS ARE STILL IN AGREEMENT THAT AFTER THE DEEP TROUGH PASSES
THROUGH THE AREA THURSDAY...IT SHOULD BE DRY UNTIL THE PASSAGE OF
ANOTHER SHORTWAVE TROUGH OCCURS SUNDAY INTO MONDAY. THIS WILL BE THE
NEXT CHANCE FOR SHOWERS. HIGHS FOLLOWING THE THURSDAY SYSTEM WILL
REMAIN BELOW NORMAL WITH READINGS IN THE UPPER 40S AND LOW 50S
FRIDAY THEN THE 60S FOR SATURDAY INTO MONDAY. FROST AND OR FREEZING
TEMPERATURES REMAIN A CONCERN PRIMARILY FOR FRIDAY AND SATURDAY
MORNINGS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 626 PM CDT MON APR 15 2013
EXPECT VFR CONDITIONS THROUGH AT LEAST THE FIRST 12 HOURS OF THE
TAF...AND PROBABLY THROUGH 18Z. CIGS IN THE 4K TO 6K FOOT RANGE
WILL PERSIST THROUGH THE NIGHT INTO TUESDAY MORNING...BUT ARE
EXPECTED TO DECREASE TO AROUND 2500 FEET DURING THE AFTERNOON. TS
APPEAR POSSIBLE AFTER 10Z-12Z BUT SHOULD BE SCATTERED. TS WILL
INITIALLY COME CLOSE TO TOP/FOE...BUT EVENTUALLY TS CHANCES SPREAD
WEST TO MHK AS WELL. AT THIS TIME...IT APPEARS THAT SCATTERED TS
POSSIBLE ALMOST ANY TIME OF DAY ON TUESDAY.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...BARJENBRUCH
SHORT TERM...53
LONG TERM...63
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
116 AM EDT TUE APR 16 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 420 PM EDT MON APR 15 2013
12Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW CLOSED UPR TROF
STRETCHING FM MN THRU THE PAC NW UPSTREAM OF UPR RDG OVER THE ERN
CONUS. SHRTWV THAT CAUSED WINTRY MIX OF PCPN SUN INTO THIS MRNG IS
LIFTING NEWD THRU MN ON THE ERN FLANK OF THE UPR TROF AXIS. DRY SLOT
ON THE ERN FLANK OF THIS DISTURBANCE HAS ADVECTED MUCH DRIER MID LVL
AIR OVER UPR MI WITH SW H7 WINDS UP TO 73 KTS AS SHOWN ON THE 12Z
GRB RAOB. SINCE WARM CONVEYOR BELT MSTR HAS ALSO SHIFTED TO THE E...
THE CWA IS PCPN FREE THIS AFTN. RETURN OF SUNSHINE UNDER THE DRY
SLOTTING OVER THE W AND CENTRAL HAS CAUSED TEMPS TO RECOVER TO MORE
SEASONABLE LVLS. OVER THE E...LO CLDS HAVE BEEN MORE PERSISTENT WITH
SSW LLVL FLOW OFF THE CHILLY LK MI WATERS AND LLVL MSTR SHOWN ON THE
12Z GRB RAOB. BKN SC HAS ALSO DVLPD OVER THE W AS DAYTIME HEATING
HAS DESTABILIZED LLVL LAPSE RATES WITH INFLUX OF LOWER H85 TEMPS AND
ARRIVAL OF MOISTER LLVL AIR DEPICTED ON THE 12Z MPX RAOB.
TNGT...SHRTWV/SFC LO IN MN ARE PROGGED TO SHIFT NEWD THRU NW
ONTARIO. ALTHOUGH SUPPORTING DEEP LYR QVECTOR CNVGC/DEEPER MSTR WL
SLIDE TO THE NW OF UPR MI...THERE MAY BE ENUF MOISTENING OVER THE W
WITH THE SLOW ARRIVAL OF COLDER AIR TO JUSTIFY RETAINING FCST OF
SCHC POPS IN THAT AREA...ESPECIALLY OVERNGT WITH A WSHFT TO AN
UPSLOPE W COMPONENT COINCIDENT WITH LO PRES TROF PASSAGE TO THE S OF
LO MOVING THRU NW ONTARIO. ALTHOUGH THERE MAY BE MORE SC OVER THE CNTRL AS
WELL...THE TRANSITION TO A MORE W WIND SHOULD AID CLRG OVER THE E.
TUE...LO PRES TROF ON THE SW FLANK OF DEPARTING SHRTWV/SFC LO TOWARD
JAMES BAY WL CROSS UPR MI BY EARLY AFTN. ALTHOUGH THERE WL LIKELY BE
QUITE A BIT OF SC IN THE MOIST CYC W-SW SHIFTING NW FLOW...SHARP INVRN
NEAR H8 SHOWN ON FCST SDNGS IN THE ABSENCE OF ANY UPR SUPPORT WL
SQUASH POPS AWAY FM THE W...WHERE UPSLOPE FLOW MIGHT GENERATE A FEW
-SHSN IN THE MRNG. AS THE LLVL FLOW TRENDS MORE ACYC DURING THE AFTN
FOLLOWING THE TROF PASSAGE AND SE OF HI PRES BLDG TOWARD NW
ONTARIO...THE SC MAY TEND TO BREAK UP IN THE AFTN...ESPECIALLY
DOWNWIND OF LK SUP WITH SPRING STABILIZATION IN THE AFTN OFF THE
WATER. DEEP MIXING TO H8-85 WL SUPPORT MAX TEMPS APRCHG 50 OVER THE
SCENTRAL WITH DOWNSLOPE NW FLOW. AREAS NEAR LK SUP WL BE COOLER.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 451 PM EDT MON APR 15 2013
THERE ARE A COUPLE OF PERIODS OF CONCERN IN THIS LONG TERM PERIOD.
THE FIRST WILL PUSH IN FROM THE SOUTHWEST WEDNESDAY EVENING THROUGH
THURSDAY MORNING...WITH A SECONDARY SURGE OF MOISTURE SLIDING ACROSS
UPPER MICHIGAN THURSDAY NIGHT INTO FRIDAY. LATE THIS WEEKEND INTO
EARLY NEXT WEEK MAY ALSO END UP BEING INTERESTING...WITH ANOTHER
SURGE OF WARM AIR PUSHES IN FROM THE SOUTH.
AT 00Z WEDNESDAY A WEAK SFC TROUGH MAY STILL BE OVER CENTRAL LAKE
SUPERIOR AND NORTHERN UPPER MICHIGAN...BUT THAT FEATURE SHOULD EXIT
QUICKLY AS THE LARGE AREA OF HIGH PRESSURE OVER CENTRAL CANADA
PUSHES INTO ONTARIO AND LAKE SUPERIOR OVERNIGHT. KEPT CONDITIONS DRY
FOR NOW...ALTHOUGH SOME OF THE SMALLER SCALE MODELS DID INDICATE A
FEW LIGHT FLURRIES OR SNOW SHOWERS. OTHERWISE...DRY CONDITIONS
SHOULD LINGER THROUGH WEDNESDAY MORNING...AS THE HIGH PRESSURE
SYSTEM SLOWLY EXITS TO EASTERN ONTARIO AND OVER JAMES BAY BY 00Z
THURSDAY.
WILL CONTINUE TO HEDGE THE FORECAST CLOSER TO THE ECMWF WITH THIS
PACKAGE UPDATE. ALTHOUGH IT IS A LITTLE WEAKER AND EASTWARD WITH
THE SURFACE LOW TO OUR SOUTH AND EAST DURING THE DAY THURSDAY...BOTH
THE GFS AND ECMWF HAVE THE SURFACE LOW OVER FAR EASTERN UPPER
MICHIGAN AT 18Z FRIDAY /ALTHOUGH THE GFS IS DEEPER WITH THE SYSTEM/.
PRECIPITATION TYPE AND AMOUNTS REMAIN A CONCERN...WITH RAIN MAINLY
CENTRAL AND EAST...CLOSER TO THE LOW. WEDNESDAY NIGHT STILL LOOKS
LIKE A POTENTIAL FOR FREEZING RAIN...WITH SURFACE TEMPERATURES OF
29-32F BETWEEN 01-11Z THURSDAY. WHILE THE TYPICAL ROADWAYS MAY STAY
WARM ENOUGH FOR WET CONDITIONS DUE TO LINGER SALT DEPOSITS ALREADY
ON THEM...AND BEING MORE WELL-TRAVELED. AS WE MOVE DEEPER INTO THE
SPRING SEASON IT BECOME INCREASINGLY DIFFICULT FOR ROADWAYS TO STAY
BELOW FREEZING FOR TOO LONG. STILL HAVE A GOOD CHANCE OF FREEZING
RAIN ACCUMULATING TO GENERALLY LESS THAN A TENTH OF AN INCH. KEPT
THE MENTION IN THE HWO AT THIS POINT. ALSO HAVE THE POTENTIAL FOR
2-4 INCHES OF HEAVY WET SNOW OVER THE HIGHER TERRAIN OF THE WEST
WEDNESDAY NIGHT...LINGERING INTO THURSDAY WITH A SMALL BREAK FIGURED
BEFORE WE COME UNDER THE INFLUENCE OF THE 500MB TROUGH AND COLDER
AIR PUSHING IN FOR THURSDAY NIGHT THROUGH FRIDAY NIGHT.
NNE 850MB WINDS OF 30-50KT LOOK REALISTIC FROM 06-15Z
FRIDAY...BEFORE TURNING MORE NORTHERLY AS THE LOW PUSHES ACROSS
EASTERN UPPER MICHIGAN. INTRODUCED GALE FORCE VALUES TO PORTIONS OF
MAINLY CENTRAL LAKE SUPERIOR FRIDAY INTO FRIDAY EVENING...BUT WOULD
NOT BE SURPRISED IF WE NEED TO BUMP UP OUR FORECAST FOR THE NE WINDS
FUNNELING DOWN THE WESTERN HALF OF LAKE SUPERIOR EARLIER IN THE DAY.
THE WEST END OF THE CWA /GOGEBIC AND ONTONAGON COUNTIES/ WILL ALSO
HAVE THE BEST CHANCE OF LAKE EFFECT/LAKE ENHANCED SNOW
ACCUMULATIONS...WITH 850MB TEMPS GENERALLY COOLING BELOW -6C.
LIGHTER AMOUNTS ARE FIGURED EAST...WITH WARMER AIR WILL AROUND AND A
MIX OF RAIN OR SNOW POSSIBLE FAR EAST THROUGH THE DAY FRIDAY.
DRY WEATHER SHOULD BE THE RULE ONCE AGAIN STARTING SATURDAY AS HIGH
PRESSURE BUILDS IN AT THE SFC. HOWEVER WITH NW FLOW LINGERING ALOFT
AND N-NNW WINDS AT THE SURFACE...ALONG WITH 850MB TEMPS OF -11 TO
-14C...LINGERING SNOW SHOWERS WILL BE POSSIBLE EAST OF MARQUETTE
NEAR LAKE SUPERIOR INTO THE MID/LATE MORNING HOURS.
THERE ARE SIGNIFICANT TIMING DIFFERENCES WITH THE APPROACH OF THE
NEXT SYSTEM. THEY DO AGREE ON STRONG S WINDS AT 850MB...AGAIN
APPROACHING THE 40-55KT RANGE FROM MAINLY LATE SUNDAY AFTERNOON
THROUGH MONDAY MORNING...AS THE LLJ PUSHES W TO E ACROSS THE CWA.
THE MAIN ISSUE IS REGARDING THE TIMING OF THE NEXT SURGE OF
MOISTURE/PRECIPITATION...WHICH THE 15/12Z GFS IS MUCH MORE
PROGRESSIVE AND BRINGS IN MORNING TO THE WEST HALF. THIS IS APPROX 6
OR MORE HOURS FASTER THAN THE 15/06Z GFS RUN. THE 12Z ECMWF SHOWED A
SLOWER SOLUTION. GIVEN THE VARIABILITY SHOWN IN THE AVAILABLE
MODELS...IT SEEMS REASONABLE TO CONCENTRATE A BIT MORE ON THE NEAR
TERM...AND RUN WITH A CONTINUED CONSENSUS APPROACH AFTER 00Z MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 115 AM EDT TUE APR 16 2013
LOW-LEVEL MOISTURE WRAPPING AROUND MIDLEVEL LOW PASSING JUST N OF
LAKE SUPERIOR WILL LIKELY RESULT IN MVFR CIGS AT KIWD/KCMX THRU THE
MORNING HRS. APPROACH AND PASSAGE OF SFC TROF LATE IN THE NIGHT
SHOULD BRING LOW MVFR CIGS (PERHAPS IFR) TO KCMX ALONG WITH THE
POSSIBILITY OF -SHSN/FLURRIES. AT KSAW...VFR CONDITIONS WILL PREVAIL
FOR THE NEXT SEVERAL HRS...BUT PASSAGE OF SFC TROF AROUND DAYBREAK
SHOULD BRING HIGH MVFR CIGS. MVFR CIGS WILL LIFT/SCATTER OUT
MID/LATE AFTN AT KIWD/KCMX. EXPECT CIGS TO RISE TO VFR BY LATE
MORNING AT KSAW. VFR CONDITIONS WILL THEN BE THE RULE THRU THE
EVENING HRS AT ALL 3 SITES.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 451 PM EDT MON APR 15 2013
SHORT LIVED GALE EVENT WILL CONTINUE TO WIND DOWN EARLY THIS MORNING
ACROSS THE EAST HALF OF LAKE SUPERIOR AS THE LOW NEARS THE AREA AND
ALSO WEAKENS WHICH WILL WEAKEN THE PRESSURE GRADIENT. WINDS THEN
DECREASE TUESDAY INTO WEDNESDAY BEFORE INCREASING OUT OF THE N
THURSDAY INTO FRIDAY WHEN GALES MAY BE POSSIBLE AGAIN AS ANOTHER
STRONG LATE SPRING SNOWSTORM AFFECTS THE AREA.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...KC
LONG TERM...KF
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1149 PM EDT MON APR 15 2013
.AVIATION...
//DISCUSSION...
A COLD FRONT NOW OVER MBS WILL SLOWLY ADVANCE ACROSS SE MI EARLY
THIS MORNING...PASSING THROUGH METRO DETROIT AROUND 09Z. A REGION OF
SHOWERS WILL OCCUR ALONG AND IN THE WAKE OF THIS COLD FRONT. THE
ADDED LOW LEVEL MOISTURE WILL RAPIDLY LOWER CEILINGS TO MVFR WITH
SOME IFR CONDITIONS POSSIBLE IN THE IMMEDIATE POST FRONTAL AIRMASS.
THE FRONTAL PASSAGE WILL ALSO BE MARKED BY AN ABRUPT SHIFT IN THE
WINDS TO THE W-NW. CONDITIONS ARE EXPECTED TO IMPROVE MARKEDLY LATE
TUES MORNING AS DRY AIR FUNNELS IN FROM THE WEST.
FOR DTW...MORE SIGNIFICANT LOWERING OF CEILINGS AND SHOWERS WILL
HOLD OFF UNTIL 09 TO 11Z GIVEN THE LATE ARRIVAL OF THE COLD FRONT.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT TUESDAY MORNING.
&&
.PREV DISCUSSION...ISSUED 959 PM EDT MON APR 15 2013
UPDATE...
THE BAND OF RAIN SHOWERS NOW EXTENDING FROM NRN IL INTO NE LOWER
MI IS ASSOCIATED WITH LOW TO MID TROPOSPHERIC FGEN ALONG A PLUME
OF DEEP LAYER MOISTURE. THUS FAR THE HIGHEST RETURNS HAVE BEEN
ALONG THE 700MB FRONT. THE 18Z NAM AND RECENT RAP ALL SUGGEST
A CONTRACTION OF THE LOWER TROPOSPHERIC THERMAL GRADIENT OVER THE
NEXT 2 TO 6 HOURS...WHICH SHOULD LEAD TO ENHANCED FGEN WITHIN THE
900-800MB LAYER. RECENT RADAR TRENDS OVER SW LOWER MI ARE IN
SUPPORT OF THIS. THERE ARE SOME INDICATIONS IN THE MODEL SOLUTIONS
THAT THE LOW LEVEL FGEN WILL FRACTURE AS IT TRAVERSES SE MI
OVERNIGHT...RAISING SOME CONCERNS THAT RAINFALL ACROSS THE FAR
EASTERN SECTIONS OF THE FORECAST AREA MAY NOT BE THAT
WIDESPREAD...PARTICULARLY FROM DETROIT DOWN TO MONROE AND ADRIAN.
THE EVENING UPDATE WILL REFLECT THIS IDEA BY A SUBTL LOWERING IN
POPS ACROSS THE FAR EAST. OTHERWISE...ONLY MINOR ADJUSTMENTS WILL
BE MADE TO THE GOING FORECAST.
PREV DISCUSSION...ISSUED 300 PM EDT MON APR 15 2013
SHORT TERM...TONIGHT
FOR THE TIME BEING, SOUTHEAST MICHIGAN REMAINS FIRMLY EMBEDDED
WITHIN THE WARM SECTOR OF A FILLING CYCLONE LIFTING ACROSS NORTHERN
MINNESOTA. ONLY A VERY SLOW EASTWARD PROGRESSION OF THE ASSOCIATED
COLD FRONT IS FORECAST AS IT IS ALREADY IN THE PROCESS OF ALIGNING
ROUGHLY PARALLEL WITH MEAN DEEP LAYER FLOW. ALTHOUGH THE FRONT,
DRAPED FROM THE WESTERN LAKES ACROSS THE MID MS VALLEY, HAS BEEN
MOSTLY DRY THROUGH THE FIRST PART OF TODAY, ONGOING/DEVELOPING
SHOWERS ACROSS MO/IL ARE SYMPTOMATIC OF INCREASING MID-LEVEL
MOISTURE TRANSPORT THAT WILL FOSTER A STEADY INCREASE IN SHOWER
COVERAGE THIS AFTERNOON THROUGH TONIGHT. AS THIS OCCURS, LOW
AMPLITUDE ENERGY WITHIN PREVAILING WSW FLOW ALOFT WILL FACILITATE A
TIGHTENING OF THE UPPER MASS GRADIENT AND SUBSEQUENT JET CORE
DEVELOPMENT ACROSS THE STRAITS BY LATE TONIGHT. SUBTLE RIGHT
ENTRANCE DYNAMICS WILL AID HIGHER RAIN RATES TO THE WEST OF THE
SURFACE FRONT AND STORM TOTALS OF AT LEAST A QUARTER OF AN INCH
ACROSS THE SAGINAW VALLEY AND WESTERN THUMB. GIVEN THAT JET
SUPPORT/MID-LEVEL FGEN WILL BE RATHER BRIEF/TRANSIENT IN NATURE, THE
EXPECTATION IS FOR EASTERN AREAS TO SEE CLOSER TO 0.1" OR SO AS THE
FRONTAL ZONE BECOMES SEPARATED FROM THE BETTER UPPER SUPPORT AND
SPINS DOWN DURING ITS PUSH ACROSS THE FORECAST AREA. HEALTHY
MOISTURE TRANSPORT AND STRONG CONVERGENCE ALONG THE SURFACE FRONT
WARRANT CONTINUANCE OF CATEGORICAL POPS FOR ALL LOCATIONS. FORECAST
REASONING WITH REGARD TO LOW-END THUNDER POTENTIAL REMAINS UNCHANGED
AS PLUME OF MODEST H85-H7 CONDITIONAL INSTABILITY WILL BE CAPABLE OF
SUPPORTING A FEW RUMBLES OF THUNDER ACROSS SEMI OVERNIGHT.
TEMPERATURES WILL FALL AROUND 10+ DEGREES INTO THE 40S WITH THE
PASSAGE OF THE FRONT LATE TONIGHT.
LONG TERM...TUESDAY THROUGH MONDAY
AS STRONG SHORTWAVE FILLS AS IT LIFTS INTO QUEBEC...FRONTAL BOUNDARY
WILL SAG SOUTH OF THE CWA AND STALL OVER THE OHIO VALLEY WITHIN THE
BROAD WEST/SOUTHWEST UPPER FLOW WHICH ENCOMPASSES THE EASTERN CONUS
IS ADVANCE OF STRONG UPPER LEVEL STORM SYSTEM DIGGING THROUGH THE
WESTERN PART OF THE NATION. RELATIVELY MOIST/MILD AIR WILL OVERRUN
THIS SHALLOW BOUNDARY AND MAINTAIN THE CHANCE OF RAIN SHOWERS OVER
THE SOUTHERN CWA ON TUESDAY WITH THE SHOWER CHANCES SLOWLY EXPANDING
BACK TO THE NORTH INTO WEDNESDAY AS THE UPPER SYSTEM IN THE WEST
BEGINS TO EMERGE OVER THE CENTRAL/SOUTHERN PLAINS AND UPPER HEIGHTS
BUILD OVER THE REGION AND FORCE THE MILD/MOIST AIRMASS NORTHWARD
WITH TIME.
SHOWERS/THUNDERSTORMS WILL BECOME INCREASINGLY LIKELY AS THE WARM
FRONT LIFTS NORTH THROUGH THE AREA LATE WEDNESDAY INTO THURSDAY
NIGHT AND STALLS NEAR THE NORTHERN CWA AS THE PLAIN/S SYSTEM LIFTS
INTO THE GREAT LAKES. AS THIS SYSTEM DEEPENS AND APPROACHES THE
REGION...FORCING ALONG THE SOUTHWEST TO NORTHEAST ORIENTED FRONT
WILL INCREASE AND PROVIDE INCREASED LIFT. AT THE SAME TIME...AN
INCREASE IN OVERALL AVAILABLE MOISTURE CAN BE EXPECTED AS THE
SOUTHWEST FLOW INCREASES AND MOISTURE POOLING BECOMES ENHANCED WITH
CONVERGENCE ALONG THIS FRONTAL BOUNDARY.
WHILE THE ENTIRE AREA WILL SHARE IN THE HIGH LIKELIHOOD OF PERIODIC
RAIN SHOWERS AND EMBEDDED THUNDERSTORMS WITH HEAVY RAINFALL DURING
THIS TIME FRAME...MODELS ARE BECOMING INCREASINGLY CONSISTENT IN
FAVORING THE SAGINAW VALLEY/NORTHERN THUMB FOR THE MOST PERSIST
ACTIVITY (HENCE THE HEAVIEST TOTAL RAINFALL ON THE ORDER OF SEVERAL
INCHES). THIS AREA OF THE CWA TOOK THE BRUNT OF LAST WEEK/S HEAVY
RAINFALL WITH 3-5 INCHES...SO FLOODING COULD ONCE AGAIN BECOME A
CONCERN.
SHOWERS WILL LINGER INTO FRIDAY...BUT IT APPEARS A STRONG DRY SLOT
WILL STRIP AWAY DEEPER MOISTURE QUICKLY AS CENTER OF THE UPPER LEVEL
STORM SYSTEM LIFTS THROUGH THE UPPER MISSISSIPPI VALLEY INTO THE
NORTHERN GREAT LAKES. THIS WILL BRING AN END TO THE HEAVIER RAINFALL
EARLY IN THE DAY WITH JUST WIDELY SCATTERED SHOWERS POSSIBLE INTO
FRIDAY NIGHT. BY THAT TIME...ENOUGH COLD AIR WILL HAVE WRAPPED INTO
THE AREA AROUND THIS LOW PRESSURE TO CHANCE ANY SHOWERS TO LIGHT
SNOW SHOWERS.
THE PATTERN THEN MODERATES TEMPORARILY BY LATE THIS WEEKEND INTO
EARLY NEXT WEEK WITHIN SHORTWAVE RIDGING IN ADVANCE OF THE NEXT
STORM SYSTEM ORGANIZING OVER THE PLAIN STATES.
MARINE...
THE FRESH TO MODERATE SOUTHERLY BREEZE WILL PERSIST UNTIL THE
PASSAGE OF A COLD FRONT LATER TONIGHT. THE PASSAGE OF THE FRONT WILL
BRING ABOUT AN ABRUPT CHANGE IN WIND DIRECTION TO WNW BY LATE
TONIGHT INTO EARLY TUESDAY MORNING ALONG WITH A SLIGHT CHANCE FOR
THUNDERSTORMS. SHORT DURATION FETCH AND A LACK OF STRONGER WINDS
WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS ACROSS AREA
WATERS THROUGH WEDNESDAY.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...JVC
LONG TERM....DG
MARINE.......JVC
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1043 PM CDT MON APR 15 2013
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT AND TUESDAY
ISSUED AT 310 PM CDT MON APR 15 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW OCCLUDED LOW
PRESSURE SPINNING OVER NORTHERN MINNESOTA AND THE OCCLUDED/COLD
FRONT NOW OVER FAR EASTERN WISCONSIN EARLY THIS AFTERNOON. AN AREA
OF LIGHT RAIN IS SPREADING NE INTO SW WISCONSIN WITHIN A FGEN BAND
BEHIND THE COLD FRONT. THIS BAND OF RAIN LOOKS TO BE A LITTLE
FARTHER NW THAN WHAT MODELS INDICATE...AND HAVE NOW INCREASED POPS
TO LIKELY OVER EAST-CENTRAL WISCONSIN LATE THIS AFTERNOON INTO THIS
EVENING. MEANWHILE...PLENTY OF LOW STRATUS IS MOVING EAST OVER
NORTHWEST WISCONSIN AND IS NOW MOVING INTO NORTH-CENTRAL WISCONSIN.
NO SIGN OF ANY PRECIPITATION OUT OF THESE CLOUDS SO FAR...AND WILL
GO WITH A DRY FORECAST. PRECIP TRENDS AND TEMPS ARE THE MAIN
FORECAST CONCERNS.
TONIGHT...OCCLUDED LOW PRESSURE WILL MOVE NORTHEAST FROM NORTHERN
MINNESOTA TO SOUTHERN ONTARIO WHILE THE COLD FRONT WILL SLOWLY SAG
SE ACROSS SOUTHERN LOWER MICHIGAN AND CENTRAL ILLINOIS. NORTH OF
THE FRONT...MODERATE MID-LEVEL FGEN WILL HAVE AN ONGOING BAND OF
LIGHT RAIN IMPACTING SOUTHEAST WISCONSIN. THE LATEST HI-RES MODEL
RUNS SHOW THE NORTHERN EDGE OF THIS LIGHT RAIN JUST CLIPPING
EAST-CENTRAL WISCONSIN THIS EVENING BEFORE PUSHING SOUTHEAST
OVERNIGHT. BUT RADAR TRENDS INDICATE THAT LIGHT RAIN IS LIKELY FROM
OSHKOSH TO KEWAUNEE THIS EVENING. HAVE INCREASED POPS ACCORDINGLY.
IN CLOSER PROXIMITY TO THE LOW PRESSURE...PLENTY OF LOW CLOUDS WILL
MOVE NE ACROSS CENTRAL AND NORTH-CENTRAL WISCONSIN TONIGHT. THESE
CLOUDS MAY RETREAT A LITTLE TO THE NORTH AS THE LOW PULLS AWAY SO
WILL GO WITH MOSTLY CLOUDY CONDITIONS FOR MUCH OF THE NIGHT. WHERE
SKIES DO CLEAR LATE TONIGHT OVER NE WISCONSIN LATE...A FAIRLY TIGHT
PRESSURE GRADIENT WILL PREVENT WINDS FROM DECOUPLING...SO SHOULD SEE
A SEASONABLE NIGHT. LOWS IN THE UPPER 20S NORTH AND WEST...TO THE
MIDDLE 30S NEAR LAKE MICHIGAN.
TUESDAY...THE COLD FRONT WILL SHIFT SOUTH INTO THE OHIO VALLEY WHILE
LOW PRESSURE WILL CONTINUE TO MARCH AWAY INTO QUEBEC. WEAK HIGH
PRESSURE RIDGE AXIS WILL SLIDE EAST INTO THE WESTERN GREAT
LAKES...BUT NORTHWEST WINDS WILL PUSH IN SLIGHTLY COLDER AIR THAN
WHATS PRESENT ACROSS THE REGION TODAY. THERMAL TROUGHING WILL LEAD
TO MORE CLOUDS ACROSS THE NORTHERN WISCONSIN THAN CENTRAL PORTIONS
OF THE STATE SO WILL GO WITH PARTLY TO MOSTLY CLOUDY WORDING. HIGHS
FALLING BACK TO AROUND 40 DEGREES NORTH TO AROUND 50 SOUTH.
.LONG TERM...TUESDAY NIGHT THROUGH MONDAY
ISSUED AT 310 PM CDT MON APR 15 2013
MAIN CHALLENGE THIS FORECAST PERIOD ARE THE TWO SURFACE LOWS
MOVING THROUGH IN RAPID SUCCESSION WEDNESDAY NIGHT AND THURSDAY
NIGHT. THE FIRST ONE HAS LITTLE COLD AIR TO WORK WITH AND SHOULD
BE LARGELY RAIN. THE EXCEPTION WOULD BE IN THE FAR NORTH WHERE
THERE MAY BE AN INCH OR TWO OF WET SNOW OR MIXED PRECIPITATION.
THE SECOND SYSTEM IS MORE INTERESTING AS THE MODELS DEEPEN IT
RATHER QUICKLY (7 TO 10 MB IN 12 HOURS) WHICH WILL RESULT IN
DYNAMIC COOLING AND PRODUCE ENOUGH COLD AIR FOR THE MUCH OF THE
PRECIPITATION TO FALL AS SNOW LATE THURSDAY NIGHT AND FRIDAY. THE
ECMWF IS THE COLDEST OF THE MODELS AND WOULD PRODUCE AT LEAST AN
ADVISORY TYPE SNOW FOR MUCH OF THE FORECAST AREA. THIS SCENARIO IS
CERTAINLY NOT A SURE THING THAT FAR OUT BUT WITH ANOTHER BIG
ARCTIC HIGH CENTERED NORTH OF THE GREAT LAKES AND WARM HUMID AIR
TO OUR SOUTH THERE SHOULD BE A DYNAMIC WEATHER SYSTEM. AFTER THAT
SYSTEM DEPARTS SOME COLD AIR MOVES INTO THE REGION FOR FRIDAY
NIGHT AND SATURDAY. TEMPERATURES MODERATE SUNDAY WITH ANOTHER
WEATHER SYSTEM EARLY NEXT WEEK.
&&
.AVIATION...FOR 06Z TAF ISSUANCE
ISSUED AT 1039 PM CDT MON APR 15 2013
STRATOCUMULUS COVERED NC/FAR NE WI LATE THIS EVENING...AND SHOULD
REMAIN ACROSS ROUGHLY THE SAME AREA OVERNIGHT. CIGS WILL BE LOW
VFR TO MVFR AT RHI/AUW/CWA THROUGH EARLY TUESDAY...FOLLOWED BY VFR
CONDITIONS FOR THE REST OF THE DAY. DAYTIME MIXING WILL CAUSE
WEST WINDS TO INCREASE BY LATE MORNING...BUT GUSTS SHOULD ONLY BE
AROUND 20 KTS. WINDS WILL DECREASE LATE IN THE DAY...THEN TURN
NORTHEAST DURING THE EVG.
&&
.HYDROLOGY...
ISSUED AT 310 PM CDT MON APR 15 2013
WARMER TEMPERATURES TODAY HAVE INCREASED SNOW/ICE MELT. THIS AND
RUNOFF FROM LAST NIGHT`S PCPN WILL BRING SOME RISES ON AREA RIVERS
AND STREAMS. WILL NEED TO MONITOR THE HYDRO SITUATION DURING THE
MID TO LATE PART OF THE WEEK...AS A COUPLE LOW PRESSURE SYSTEMS
ARE EXPECTED TO BRING SIGNIFICANT PCPN FROM WEDS NGT THROUGH FRIDAY.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......RDM
AVIATION.......KIECKBUSCH
HYDROLOGY......MPC/KIECKBUSCH
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1006 PM CDT MON APR 15 2013
.UPDATE...
A 120 KNOT JET MAX AT 250 MB IS PUSHING ACROSS WISCONSIN AND WILL
REACH THE LAKE HURON AREA EARLY THIS MORNING. STILL SOME UPPER
DIVERGENCE UNTIL THE JET MAX MOVES OFF. 700 MB UPWARD MOTION STILL
ACROSS FAR SOUTHEAST WISCONSIN AT 1 AM BUT THEN PUSHES QUICKLY
NORTHEAST WITH THE JET MAX.
AS A RESULT THE LIGHT RAIN WILL CONTINUE IN THE FAR SOUTHEAST
UNTIL AROUND 3 AM...THEN A BRIEF RESPITE AS WEAK HIGH PRESSURE
PUSHES INTO WISCONSIN ON TUESDAY. 00Z NAM INDICATES THE LIGHT RAIN
MAY HOLD OFF UNTIL EARLY EVENING TUESDAY.
&&
.AVIATION/06Z TAFS/...
MAINLY VFR CONDITIONS WITH SOME MVFR VSBYS POSSIBLE IN RAIN UNTIL
AROUND 07Z. A 120 KNOT JET MAX AT 250 MB IS PUSHING ACROSS
WISCONSIN AND WILL REACH THE LAKE HURON AREA EARLY THIS MORNING.
AS A RESULT THE LIGHT RAIN WILL CONTINUE IN THE FAR SOUTHEAST
UNTIL AROUND 07Z THEN A BRIEF RESPITE AS WEAK HIGH PRESSURE PUSHES
INTO WISCONSIN ON TUESDAY. 00Z NAM INDICATES THE LIGHT RAIN MAY
HOLD OFF UNTIL EARLY EVENING TUESDAY.
&&
.PREV DISCUSSION... /ISSUED 342 PM CDT MON APR 15 2013/
VERY SHORT TERM...TONIGHT AND TUESDAY.
TONIGHT - CONFIDENCE...MEDIUM
PER WATER VAPOR STRONG SOUTHWEST UPPER JET ROUNDING BASE OF TROUGH
NRN MN CIRCULATION CENTER. MODELS ALSO SHOWING DECENT 850/700
MILLIBAR FRONTOGENETICAL FORCING ACROSS PORTIONS OF SRN WI. RAIN
AREA ALREADY WORKING INTO SRN WI. EXPECTED TO AFFECT MUCH SRN WI
INTO THE EVENING HOURS. COMBO OF HRRR AND SPC WRF SUGGESTS BULK OF
PRECIP WILL BE AFFECTING SE 1/2 OF THE CWA DURING THE EVENING HOURS.
TUESDAY - CONFIDENCE...MEDIUM
HIGH PRESSURE GRADUALLY BUILDS IN. MODELS HAVE TRENDED THE QPF
FURTHER SOUTH. 12Z ECMWF DOES HAVE LIGHT QPF IN THE FAR SOUTH DURING
THE AFTERNOON SO HAVE RETAINED A SMALL POP BUT CONFIDENCE NOT GREAT.
THERE IS AN INDICATION OF AN INVERTED TROUGH AND POSSIBLY SOME RIGHT
REAR DIVERGENCE OF JET CORE TO OUR NORTH. SOUNDINGS SHOW LOW LEVELS
BELOW 5K FEET DRY BUT MID LEVEL SATURATION WITH OMEGA WITH SOME
PROGGD FRONTOGENETICAL FORCING IN THE 700-500 MILLIBAR LAYER.
SHORT TERM...TUESDAY NIGHT THROUGH THURSDAY.
TUESDAY NIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
12Z NAM BRINGS QPF INTO THE FORECAST AREA WITH ISENTROPIC
LIFT/850-700 MB FRONTOGENESIS/850 MB CONVERGENCE AS IT LIFTS 850/700
MB BAROCLINIC ZONES FARTHER NORTH THAN OTHER MODELS. 12Z ECMWF
BRINGS THE PCPN IN TUESDAY AFTERNOON THEN EAST IN THE EVENING...BUT
THE 850MB CONVERGENCE IS BETTER AFTER 06Z WEDNESDAY. IN SPITE OF
RELATIVELY DRY EAST FLOW...WILL KEEP CHANCE POPS IN THE FAR
SOUTH.
WEDNESDAY THROUGH THURSDAY NIGHT...FORECAST CONFIDENCE MEDIUM TO
HIGH.
ELONGATED TROUGH OF SURFACE LOW PRESSURE...WITH MODELS SHOWING TWO
DISTINCT CENTERS...WILL LIFT INTO THE REGION AHEAD OF DEEP LONG WAVE
TROUGH AND THEN CONSOLIDATE OVER THE WESTERN GREAT LAKES. COPIOUS
AMOUNTS OF MOISTURE STREAMING INTO THE REGION WILL PRODUCE PERIODS
OF MODERATE TO HEAVY RAIN.
SOME TRACK LOCATION DIFFERENCES THAT IMPACT THE AMOUNT OF
INSTABILITY AND AREAL EXTENT OF THUNDERSTORMS...BUT CONSENSUS
FORECAST QPF OF 1.6 TO NEARLY 3 INCHES OF RAIN LOOKS TO OCCUR WITH
ONLY ISOLATED THUNDERSTORMS...WITH HIGHER AMOUNTS IF THUNDER BECOMES
MORE WIDESPREAD. HAVE ISSUED AN ESF TO HIGHLIGHT RISK OF INCREASED
FLOODING ACROSS THE REGION...WITH SATURATED GROUND UNABLE TO HOLD
MUCH ADDITIONAL RAINFALL AND MANY RIVERS ALREADY IN OR NEAR
FLOOD.
COLDER AIR WRAPPING IN BEHIND THE LOW WILL BRING A MIX OF RAIN AND
SNOW AFTER MIDNIGHT THURSDAY NIGHT...WITH ALL SNOW EXPECTED
NORTHWEST OF MADISON BY 12Z FRIDAY. BETTER DEFORMATION TO THE
NORTHWEST OF THE FORECAST AREA AND LIGHT QPF AMOUNTS AS TEMPERATURES
COOL SO ONLY MINOR ACCUMULATIONS EXPECTED.
NOT MUCH OF A CHANGE IN TEMPERATURES BETWEEN HIGHS WEDNESDAY AND
OVERNIGHT LOWS WITH EXPECTED NON-DIURNAL TREND. HIGHS NEAR 60 IN THE
FAR SE...THOUGH WARMER GFS MOS GUIDANCE IS PUSHING NEAR 70 IN THE
SOUTH.
LONG TERM...FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE LOW TO
MEDIUM.
KEEPING CHANCE POPS FOR FRIDAY AS REGION REMAINS UNDER THE CYCLONIC
FLOW OF 500 MB TROUGH OVER THE CENTRAL U.S. AT START OF THE
PERIOD...WITH DRY WEATHER FROM OVERNIGHT FRIDAY THROUGH SATURDAY
NIGHT IN NW FLOW AS THE TROUGH SLOWLY PUSHES EAST. ANOTHER
WAVE COMES ASHORE IN THE PACIFIC NW FRIDAY AFTERNOON...REACHING THE
CENTRAL/SRN PLAINS BY SUNDAY MORNING....WHILE ANOTHER WAVE TRACKS
ALONG THE US/CANADIAN BORDER RIGHT BEHIND. THIS BRINGS THE CHANCE
FOR WET WEATHER BACK INTO THE FORECAST SUNDAY THROUGH THE REST OF
THE EXTENDED. BELOW NORMAL TEMPS FRIDAY AND SATURDAY WARM TO NEAR
NORMAL LEVELS SUNDAY AND MONDAY.
AVIATION/00Z TAFS/...UPPER JET AND LOWER LEVEL FRONTOGENETICALLY
INDUCED AREA OF RAIN TO MOVE THROUGH SOUTHERN WI THIS EVENING. MVFR
CEILINGS/VSBYS POSSIBLE. SOUNDINGS SHOW INITIALLY DRY LAYER IN THE
LOW LEVELS...THIS PROGGD TO MOISTEN UP. WILL GO WITH A MID DECK FOR
TUESDAY WITH LOWER LEVELS FAIRLY DRY. AFTERNOON SHOWERS POSSIBLE IN
FAR SRN WI BUT CONFIDENCE TOO LOW FOR INCLUSION IN TAFS.
MARINE...SOUTHWEST WINDS STILL GUSTING OVER CRITERIA SO WILL RETAIN
HEADLINE THROUGH 7 PM EXPIRATION. GRADIENT SLACKENS UP TONIGHT. HIGH
GRADUALLY BUILDS IN TUESDAY. WINDS GO NORTHEAST BUT NOT HIGH ENOUGH
TO WARRANT SMALL CRAFT CONCERNS AT THIS TIME.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...HENTZ
TONIGHT/TUESDAY AND AVIATION/MARINE...COLLAR
TUESDAY NIGHT THROUGH MONDAY...REM
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
1147 AM EDT TUE APR 16 2013
.UPDATE...
HAVE MADE SEVERAL TWEAKS TO THE GRIDS. MAIN CHANGES HAVE BEEN TO
INCREASE DEWPOINTS AND POPS...ESPECIALLY FOR THIS AFTERNOON. ALL
HI-RES MODELS INDICATING AN INCREASE IN CONVECTIVE COVERAGE
BETWEEN 18-00Z. SURFACE DEWPOINTS ARE ACTUALLY QUITE A BIT HIGHER
THAN FORECAST. LIMITING FACTOR WILL BE CAPE IN THE MIDLEVELS...AS
NOTED ON THE 12Z KFFC SOUNDING WITH A WEAK WARM NOSE AT ABOUT
640MB. EVEN MODIFYING THIS WARM NOSE /DECREASE TO 1C INSTEAD OF
3C/ ONLY YIELDS ABOUT 500 J/KG SBCAPE. HOWEVER...WITH SUCH A
STRONG SHORTWAVE PUSHING INTO THE AREA AS EVIDENT ON WATER VAPOR
LOOPS...THE LIFTING MAY SERVE TO COOL THAT WARM NOSE FURTHER. KBMX
HAS A HINT OF THE WARM NOSE AND KOHX DOES NOT SHOW IT...SO WITH
THE WESTERLIES ALOFT ADVECTING THAT AIRMASS THIS WAY IT WILL BE A
MATTER OF THESE COMPETING FACTORS. SO THAT SAID...HAVE INCREASED
POPS FOR NOW TO CHANCE...THOUGH IF YOU BELIEVE THE HRRR POPS MAY
NEED TO BE INCREASED SOME MORE FOR THIS AFTERNOON...AND INCREASED
THUNDER WORDING TO CHANCE /SCATTERED/ AS WELL. NOT TOTALLY SOLD ON
THE HIGHER COVERAGE THAT THE HRRR IS INDICATING BUT AT LEAST HAVE
TRENDED IN THAT DIRECTION. UPDATED PRODUCTS WILL BE OUT SHORTLY.
TDP
&&
.PREV DISCUSSION... /ISSUED 735 AM EDT TUE APR 16 2013/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
WEAK UPPER-LEVEL RIDGING PERSISTS OVER THE REGION THROUGH WEDNESDAY.
INFLUENCE OF THE RIDGE WILL LIKELY KEEP CHANCES FOR AFTERNOON
CONVECTION AT A MINIMUM TODAY ALTHOUGH INSTABILITY IS SUFFICIENT FOR
A MENTION OF A SLIGHT CHANCE OVER THE WESTERN THIRD TO HALF OF NORTH
AND CENTRAL GEORGIA. YESTERDAY EVENINGS SOUNDING SHOWS SIGNIFICANT
COOLING WOULD BE NEEDED IN THE 700-400MB LEVELS FOR ANY SIGNIFICANT
SEVERE WEATHER THREAT...AND THAT DOES NOT APPEAR TO BE LIKELY TODAY.
BY WEDNESDAY THE RIDGE AXIS IS SHIFTING EAST OF THE STATE ALLOWING
FOR CHANCE POPS OVER THE WEST AND SLIGHT CHANCE POPS TO SPREAD EAST
OVER THE REMAINDER OF THE FORECAST AREA. ALTHOUGH AN ISOLATED STRONG
STORM OR TWO CANNOT BE RULED OUT...INSTABILITY IS EXPECTED TO REMAIN
TOO MARGINAL FOR A MENTION OF SEVERE THUNDERSTORMS AT THIS TIME.
20
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LONG TERM PERIOD BEGINS WITH DEVELOPING SOUTHERLY FLOW WHICH
SHOULD ACT TO SHUNT MOISTURE AXIS NORTH OF THE AREA. WILL STILL
CARRY RESIDUAL 20 POPS FOR THE NORTH INTO THE FIRST PART OF THE
OVERNIGHT PERIOD BUT QUICKLY DISSIPATE AFTER 06Z THU. ANOTHER
ROUND POSSIBLE THU BUT OVERALL TRENDS ARE FOR LESS DIURNAL
COVERAGE GIVEN SLIGHTLY LESS MOISTURE AND CORRESPONDINGLY LESS
INSTABILITY.
MODELS STILL IN GOOD AGREEMENT WITH EXCELLENT RUN TO RUN
CONSISTENCY WRT NEXT STORM SYSTEM WHICH LOOKS TO EJECT OUT OF THE
CENTRAL PLAINS THURSDAY AND MOVE INTO THE MID MISSISSIPPI VALLEY
THURSDAY NIGHT. TIMING FOR THE LOCAL AREA INDICATES BAND OF
SHOWERS AND SCATTERED THUNDERSTORMS REACHING NW GEORGIA JUST PRIOR
TO 12Z FRIDAY. INSTABILITY STILL LOOKS MARGINAL FOR THIS EVENT
WITH ONLY A NARROW SLIVER OF 200J/KG TO 400J/KG SURFACE BASED CAPE
TO WORK WITH FOR NORTHERN SECTIONS. SLIGHTLY MORE INSTABILITY TO
THE SOUTH WITH THIS SYSTEM AND WILL HAVE INCREASED THUNDER CHANCES
ROUGHLY FROM THE ATLANTA METRO SOUTHWARD. 850MB JET IS VERY
IMPRESSIVE WITH THIS SYSTEM WITH NEARLY 90 KTS INDICATED FOR THE
OHIO VALLEY. OUR AREA ONLY GETS THE SOUTHERN END OF THIS BUT STILL
GOOD ENOUGH FOR 65 KTS FOR NW CORNER. INSTABILITY LOOKS TO BE
AHEAD OF MAIN WIND CORE SO TIMING MAY NOT LINE UP FOR THIS ONE.
REGARDLESS...925MB WINDS ARE 50KTS OVER THE LOCAL AREA WHICH
SHOULD RESULT IN NEAR SEVERE WINDS EVEN WITH THE ABSENCE OF ROBUST
CONVECTION. WILL BEGIN TO RAMP UP WORDING IN HWO.
ONCE SYSTEM CLEARS...BENIGN BUT COLD CONDITIONS FOR THIS TIME OF
YEAR WITH LOWS RETURNING TO THE 30S.
DEESE
AVIATION...
12Z UPDATE...
MAINLY IFR CONDITIONS PREVAILING ACROSS THE FORECAST AREA AT THIS
TIME. I EXPECT IFR...WITH LOCAL LIFR...CEILINGS AND VISIBILITIES TO
LAST THROUGH 14Z...IMPROVING TO MOSTLY MVFR CONDITIONS ACROSS THE
AREA 14-19Z WITH VFR EXPECTED AFTER. ISOLATED SHOWERS AND
THUNDERSTORMS ARE POSSIBLE ACROSS THE WESTERN HALF OF THE FORECAST
AREA THIS AFTERNOON...BUT PROBABILITIES AT TAF SITES TOO LOW TO
INCLUDE IN THE TAFS AT THIS TIME. WINDS WILL REMAIN EAST TO
SOUTHEAST THROUGH THE FORECAST PERIOD. WINDS SPEEDS WILL REMAIN 6KT
OR LESS THROUGH 14Z...INCREASING INTO THE 6-9KT RANGE THROUGH 22Z
BEFORE DIMINISHING TO 6KT OR LESS AGAIN.
//ATL CONFIDENCE...12Z UPDATE...
MEDIUM CONFIDENCE ON TIMING OF CIGS/VIS TRENDS THIS MORNING.
HIGH CONFIDENCE ON ALL OTHER ELEMENTS.
20
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 79 59 80 60 / 20 10 30 20
ATLANTA 78 63 80 62 / 40 20 30 20
BLAIRSVILLE 76 57 78 59 / 30 20 30 20
CARTERSVILLE 81 59 81 60 / 40 20 30 20
COLUMBUS 83 64 83 63 / 20 10 20 20
GAINESVILLE 78 62 80 61 / 30 20 30 20
MACON 82 61 82 61 / 20 5 20 20
ROME 81 59 81 61 / 40 20 30 20
PEACHTREE CITY 78 58 81 58 / 40 20 30 20
VIDALIA 81 62 83 63 / 5 0 10 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1034 AM CDT TUE APR 16 2013
.DISCUSSION...
ISSUED 1030 AM CDT TUE APR 16 2013
COLD FRONT HAS PUSHED JUST SOUTH OF OUR CWA...BUT WAS CLOSE ENOUGH
TO LAWRENCEVILLE THAT TEMPERATURES THERE ARE STILL IN THE MID 60S.
MOSTLY SEEING 40S ELSEWHERE WITH SOME LOWER 50S. ELEVATED
CONVECTION NORTH OF THE BOUNDARY HAS BEEN INCREASING OVER CENTRAL
ILLINOIS AS IT MOVES OUT OF MISSOURI...AND COVERED MOST OF THE
CWA AT 1030 AM EXCEPT FOR THE FAR NORTHWEST AND FAR SOUTHEAST.
LATEST RAP MODEL SHOWING THE SCATTERED CONVECTION CONTINUING
ACROSS MUCH OF THE CWA INTO THIS AFTERNOON...WITH LESS COVERAGE
NORTHWEST OF THE ILLINOIS RIVER. HAVE SENT OUT SOME ZONE/GRID
UPDATES TO INCREASE THE RAIN CHANCES TODAY...WITH SOME MINOR
ADJUSTMENTS TO TEMPERATURES REQUIRED AS WELL.
GEELHART
&&
.HYDROLOGY...
ISSUED 1030 AM CDT TUE APR 16 2013
EARLY LOOK AT 12Z MODEL RUNS CONTINUE TO SUPPORT AN INCREASING
POOL OF MOISTURE INTO ILLINOIS ON WEDNESDAY...WITH PRECIPITABLE
WATER VALUES UP TO AROUND 1.5 TO 1.6 INCHES BY LATE WEDNESDAY
AFTERNOON...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL.
BULK OF THE HEAVIEST RAIN EXPECTED WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. LATEST QPF FORECAST SHOWS OVER 3 INCHES ACROSS A
LARGE PART OF THE FORECAST AREA THROUGH FRIDAY...WITH 2-3 INCHES
ACROSS ABOUT THE SOUTHEAST THIRD. PROBABILITY FORECASTS FROM THE
WEATHER PREDICTION CENTER SHOW A 50-60 PERCENT CHANCE OF RECEIVING
AT LEAST 2.5 INCHES OF RAIN FROM WEDNESDAY EVENING THROUGH
THURSDAY EVENING.
CURRENTLY ONLY THE ILLINOIS RIVER AT HAVANA AND BEARDSTOWN ARE IN
FLOOD...BUT MORE FLOODING IS EXPECTED ACROSS MANY RIVERS. STANDARD
RIVER FORECASTS ONLY ACCOUNT FOR 24-HOUR QPF...BUT RFC CONTINGENCY
FORECASTS BASED ON 72-HOUR QPF SHOW POTENTIAL FOR MODERATE OR
MAJOR FLOODING IN SOME CASES.
HAVE SENT OUT A HYDROLOGIC OUTLOOK TO ADDRESS THE HEAVY RAIN
POTENTIAL...WHILE REMAINING MODEL GUIDANCE IS DIGESTED TO
DETERMINE THE POTENTIAL FOR ANY FLOOD WATCHES WITH THE AFTERNOON
FORECAST PACKAGE.
GEELHART
&&
.AVIATION...
ISSUED 645 AM CDT TUE APR 16 2013
CLOUDS REMAIN OVER THE REGION AND WILL LIKELY STAY THAT WAY
THROUGH THE PERIOD. MAIN QUESTION IS WHAT WILL THE CIG HEIGHTS BE
THROUGH THE PERIOD AND WHEN WILL PCPN RETURN. SPI/PIA/BMI WILL ALL
BE VFR AT START AND THROUGH MOST OF THE PERIOD...UNTIL PCPN MOVES
BACK OVER THE SITES LATE THIS EVENING AND INTO THE OVERNIGHT
HOURS. FOR DEC...BASED ON SATELLITE TRENDS BELIEVE DEC WILL START
AS VFR...BUT LOWER MVFR CIGS MAY LINGER IN THE AREA FOR COUPLE OF
HOURS...SO HAVE 2HR TEMPO GROUP FIRST COUPLE OF HOURS THIS
MORNING. BASED ON SATELLITE TRENDS...CMI SHOULD START WITH MVFR
CIGS...BUT IFR CIGS ARE THERE NOW SO HAVE A ONE HOUR TEMPO GROUP
FOR IFR AND THEN 2HR TEMPO GROUP FOR MVFR CIGS...SINCE VFR CIGS
SHOULD BE AT THE SITE IN NEXT COUPLE OF HOURS. THEN DEC AND CMI
SHOULD BE VFR THROUGH THE DAY...AND LIKE THE OTHER SITES...NOT
BECOME MVFR TIL PCPN MOVES BACK INTO THE AREA. UNSURE HOW LOW CIGS
WILL GET LATER TONIGHT WITH PCPN...BUT WILL START WITH MVFR...BUT
COULD GET LOWER. WINDS WILL BE NORTHERLY TO START TODAY AND THEN
GRADUALLY SHIFT TO NORTHEAST-EAST BY THIS EVENING. WIND SPEEDS
WILL BE AROUND 10KTS OR LESS THROUGH THE PERIOD.
AUTEN
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT TUE APR 16 2013
VERY UNSETTLED WEATHER PATTERN TO OCCUR THROUGH FRIDAY ACROSS
CENTRAL AND SE IL WITH PERIODS OF SHOWERS AND THUNDERSTORM GIVING
2-4 INCHES OF RAIN BY FRIDAY WITH THE HEAVIEST AMOUNTS FROM I-55 NW.
SPC ALSO CONTINUES SLIGHT RISK OF SEVERE STORMS ACROSS AREAS WEST OF
I-57 WED NIGHT AND ACROSS MUCH OF REGION THU/THU EVENING. LIKE
YESTERDAYS MODEL RUNS...THE 00Z MODEL SUITE TODAY CONTINUES SLOWER
TREND WITH POTENT COLD FRONT MOVING EASTWARD ACROSS IL THU
AFTERNOON/EVENING.
SHORT TERM...TODAY THROUGH FRIDAY
MCS FROM CENTRAL MO NE ACROSS CENTRAL IL INTO NW INDIANA HAS
GRADUALLY BEEN WEAKENING THE PAST HOUR OR SO. A BROKEN LINE OF
THUNDERSTORMS WITH HEAVY RAINS WAS ALONG SE EDGE OF THIS MCS FROM
TAYLORVILLE AND SHELBYVILLE TO TUSCOLA AND CHRISMAN. HAD A FEW
REPORTS OF HAIL BETWEEN MIDNIGHT AND 1 AM OVER PARTS OF SANGAMON AND
LOGAN COUNTIES. COLD FRONT HAD SAGGED SLOWLY INTO SE IL...SE OF
I-70 EARLY THIS MORNING BEING PULLED SE BY MCS AND 1012 MB LOW
PRESSURE NEAR INDY. COLD FRONT EXTENDED SW TO A 1000 MB LOW
PRESSURE OVER EASTERN NM. BROAD SW UPPER LEVEL FLOW OVER THE
COUNTRY HAS BEEN SLOWLY DOWN THE SE PROGRESSION OF THIS COLD FRONT.
RADAR ESTIMATED 1.5-2.5 INCHES OF RAIN ALONG AND JUST SE OF A
RUSHVILLE TO BLOOMINGTON LINE.
CONVECTION TO CONTINUE TO WEAKEN DURING THE MORNING WITH AS LOW
LEVEL JET THAT PEAKED AROUND 40 KTS WEAKENS. BEST CHANCES OF
SHOWERS AND THUNDERSTORMS TODAY SHIFTS INTO SE IL CLOSER TO
FRONTAL BOUNDARY WHICH CONTINUES TO SLOWLY SAG SOUTHWARD TODAY...
WHILE DRIER AND COOLER TO THE NORTH. SCATTERED SHOWERS AND
THUNDERSTORMS POSSIBLE THIS AFTERNOON ESPECIALLY FROM I-72 SOUTH.
HIGHS TODAY RANGE FROM THE MID 50S OVER THE IL RIVER VALLEY FROM
I-55 NW TO THE UPPER 60S TO NEAR 70F IN FAR SE IL ALONG HIGHWAY
50.
INCREASING LOW LEVEL JET TO INCREASE CHANCES OF SHOWERS AND
THUNDERSTORMS TONIGHT ESPECIALLY OVERNIGHT WHEN SPC HAS SLIGHT
CHANCE OF SEVERE OVER SE IL AND SW OF SPRINGFIELD. MAINLY A HAIL
THREAT SW OF SPRINGFIELD WHILE HAIL AND WIND IN FAR SE IL NEAR
HIGHWAY 50.
FRONTAL BOUNDARY TO BEGIN TO LIFT BACK NORTHWARD OVER CENTRAL IL
WED WITH SHOWERS AND THUNDERSTORMS LIKELY ESPECIALLY NW AREAS.
HIGHS RANGE FROM THE MID 60S NW OF THE IL RIVER TO THE UPPER 70S
AND LOWER 80S ACROSS SE IL. BEST CHANCES OF SHOWERS AND
THUNDERSTORMS OVER THE AREAS WED NIGHT THROUGH THU NIGHT AS STRONG
COLD FRONT MOVES EASTWARD OVER IL THU AFTERNOON/EVENING. SPC HAS
MUCH OF AREA IN A SLIGHT RISK OF SEVERE STORMS DURING THIS TIME
FOR DAMAGING WIND GUSTS WITH A SQUALL LINE AND LARGE HAIL ALSO
A RISK. HEAVIEST RAINS TO OCCUR WED NIGHT THROUGH THU NIGHT WITH
2-4 INCHES POSSIBLE AND HEAVIEST OVER THE IL RIVER VALLEY. HIGHS
THU TRICKING DEPENDING ON HOW FAST COLD FRONT MOVES INTO AREA...
BUT UPPER 70S AND LOWER 80S POSSIBLE OVER EASTERN IL ESPECIALLY
NEAR THE WABASH RIVER WHILE TEMPS EXPECTED TO FALL OVER THE IL
RIVER VALLEY THU AFTERNOON.
COLD FRONT PASSES EAST OF IL FRI BUT STRONG UPPER LEVEL TROF
MOVING INTO AREA TO CONTINUE LOW CLOUDS ALONG WITH A GOOD CHANCE
OF SHOWERS. COULD BE COLD ENOUGH FOR A CHANCE OF LIGHT SNOW
SHOWERS TOO NORTH OF PEORIA FRIDAY MORNING THOUGH BEST CHANCES OF
SNOW SHOWERS IS FURTHER NW OVER NW IL. HIGHS FRI ONLY 45-50 OVER
CENTRAL IL AND LOWER 50S IN SE IL.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
CANADIAN HIGH PRESSURE TO BUILD INTO IL SAT AND BRING DRY BUT COOL
WEATHER FRIDAY NIGHT THRU SAT NIGHT. LOWS FRIDAY NIGHT IN THE
LOWER 30S CENTRAL IL AND MID 30S SE IL. HIGHS SAT IN THE LOW TO
MID 50S. LOWS SAT NIGHT IN THE MID TO UPPER 30S. CANADIAN HIGH
DRIFTING INTO THE EASTERN GREAT LAKES REGION SUNDAY TO ALLOW TEMPS
TO MODIFY INTO THE UPPER 50S AND LOWER 60S SUNDAY AND INTO THE LOW
TO MID 60S MONDAY. A COLD FRONT APPROACHING THE MS VALLEY MONDAY
TO GIVE CENTRAL AND WESTERN IL CHANCES OF SHOWERS AND ISOLATED
THUNDERSTORMS WHICH CONTINUES ACROSS AREA MONDAY NIGHT/TUE AS COLD
FRONT SWEEPS THROUGH BRINGING COOLER AIR TUE ON BREEZY NW WINDS.
ECMWF AND GFS MODELS FAIRLY SIMILAR WITH THIS WEATHER SYSTEM EARLY
NEXT WEEK.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
1008 AM EDT TUE APR 16 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL CROSS JUST NORTH OF THE REGION
TONIGHT. OTHERWISE...HIGH PRESSURE BECOMES CENTERED OFF THE MID
ATLANTIC COAST FOR MOST OF THIS WEEK. A MORE VIGOROUS COLD FRONT
WILL IMPACT THE AREA FRIDAY INTO SATURDAY..
&&
.NEAR TERM /THROUGH TONIGHT/...
OVERALL CONDITIONS IMPROVE AS CLOUDY SKIES THIS MORNING BREAK UP
DURING THIS AFTN AND TEMPS WARM TOWARD 70-75 DEGREES AREAWIDE...EXCEPT AT
THE BEACHES WHERE TEMPS WILL BE IN THE 60S DUE TO PERSISTENT
ONSHORE FLOW. THE LOCAL WRF AND THE RAP MODELS ALL SHOW THE
MOISTURE SLOW TO MIX OUT IN THE WEST IN THE 925 TO 850 MB LAYER.
THEY DO SHOW THAT LEVEL WINDS SLOWLY MOVING TO SOUTHWEST AND
DRYING DEVELOPING. WILL ALSO KEEP TEMPERATURES COOLER IN THE WEST
INITIALLY WITH MORE CLOUD COVER. FOR TONIGHT...A COLD FRONT
PASSES ACROSS NEW ENGLAND AND WILL DRAG A WEAK BOUNDARY ACROSS
NWRN PORTIONS OF THE FA OVERNIGHT. THIS FEATURE WILL BRING
INCREASED CLOUDS TO THIS AREA WITH PARTLY CLOUDY SKIES FARTHER TO
THE SE. LOW TEMPS WILL RUN ABOUT 5 DEGREES ABOVE NORMAL AS CLOUD
COVER INSULATES THE ATMOSPHERE TONIGHT. EXPECT LOWS IN THE MID TO
UPPER 50S REGIONWIDE (LOW TO MID 50S IMMEDIATE COAST).
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
WED/WED NIGHT...RELATIVELY FLAT UPPER LEVEL RIDGING AND SW FLOW
OVER THE TN VALLEY AND SPINE OF THE APPALACHIANS WILL ALLOW
MOISTURE AND WEAK SHORTWAVE ENERGY TO MOVE AROUND THE PERIPHERY OF
THE UPPER RIDGE DURING THE AFTN/EVENING. THE DEVELOPMENT OF A LEE
TROUGH IS ALSO POSSIBLE AS THE FRONT FROM TUE NIGHT STALLS ACROSS
SE VA/NE NC. UNLIKE MOST LEE TROUGHS THAT TEND TO DEVELOP OVER THE
ERN PIEDMONT...THIS ONE IS EXPECTED TO TAKE ON MORE OF A
POSITIVELY TILTED ORIENTATION (ENE TO WSW). INCREASING TEMPS AND
DEWPOINTS DURING THE DAY WILL CREATE ENOUGH LOW-LEVEL INSTABILITY
FOR LIGHT SHOWERS TO BE POSSIBLE NORTH OF THE TROUGH AXIS.
HOWEVER...WEAK DYNAMICS AND VERY LIGHT WINDS BELOW 500 MB WILL
LIMIT THUNDER POTENTIAL TO A SLIGHT CHANCE IN THE AFTN/EVENING.
EXPECT A NICE WARM-UP WITH HIGHS IN THE LOWER 80S FOR MOST
AREAS...IN THE MID-UPPER 70S FOR THE IMMEDIATE COAST...AND IN THE
UPPER 60S NEAR OCEAN CITY MD. ANY SHOWERS THAT DEVELOP SHOULD
DISSIPATE QUICKLY AROUND SUNSET DUE TO THE LOSS OF DAYTIME HEATING
AND BECAUSE OF THE WEAK DYNAMICS ALREADY PRESENT. MOSTLY CLOUDY
SKIES WILL ONCE AGAIN HAMPER LOW TEMPS FROM DROPPING TO THEIR FULL
POTENTIAL. LOWS SHOULD GENERALLY BE AROUND 60 (MID-UPPER 50S
IMMEDIATE COAST).
THU/THU NIGHT...THE MID AND UPPER LEVEL RIDGE AXES MOVE OFFSHORE ON
THU. SW FLOW ALOFT WILL RESULT IN WAA TAKING PLACE THUS ALLOWING
HIGH TEMPS TO WARM A FEW MORE DEGREES AS COMPARED TO WED. AN
APPROACHING COLD FRONT MOVING ACROSS THE CTRL U.S. WILL CAUSE THE
SFC PRESSURE GRADIENT TO TIGHTEN...THEREFORE GUSTS OF 20-25 MPH ARE
ANTICIPATED DURING THE AFTN. ASIDE FROM BREEZY CONDITIONS...THU
WILL BE A RATHER NICE DAY ACROSS THE AREA. THE VIGOROUS COLD FRONT
CONTINUES TO DIG INTO THE MIDWEST THU NIGHT...ACTING TO SLOW ITS
EWD PROGRESSION INTO THE MID ATLANTIC REGION. SFC WINDS WILL
BECOME MORE SLY THU NIGHT AND REINFORCE ONGOING WAA PROCESSES. THE
COMBINATION OF WAA AND INCREASING HIGH CLOUDS FROM THE APPROACHING
SYSTEM WILL ALLOW LOW TEMPS TO RUN ABOUT 10-15 DEGREES ABOVE
SEASONAL NORMALS. LOWS SHOULD GENERALLY BE IN THE LOWER 60S (55 TO
60 IMMEDIATE COAST).
FRI...THE APPROACHING (AND VIGOROUS) COLD FRONT WILL CONTINUE TO
APPROACH THE MID ATLANTIC REGION ON FRI. SLY SFC WINDS WILL INCREASE
FURTHER WITH GUSTS OF 25-30 MPH LIKELY AS THE PRESSURE GRADIENT
TIGHTENS EVEN MORE. THERE ARE SOME INDICATIONS THAT PRECIPITATION
GENERATION MAY NOT OCCUR UNTIL FRI AFTN...BUT HAVE KEPT THE
MORNING FORECAST INTACT FOR NOW WITH CHC SHOWERS FOR THE ERN
PIEDMONT AND SCHC SHOWERS AS FAR AS THE MID ATLANTIC COAST. FOR
THE AFTN...LEE TROUGH DEVELOPMENT IS ANTICIPATED DUE TO
TEMPERATURE DIFFERENCES AHEAD OF AND BEHIND THE FRONT. ALSO...
ISENTROPIC SFCS INDICATE 40-50 KT OF SW FLOW WITH THE BEST
MOISTURE IN THE PIEDMONT DURING THE AFTN. DUE TO THE SLOWER NATURE
OF DIGGING SYSTEMS...THE FRONT SHOULD BE DELAYED AND BEST PRECIP
CHANCES SHOULD OCCUR IN THE PIEDMONT THU AFTN ALONG THE LEE TROUGH
AXIS WITH MORE SHOWERS DEVELOPING FARTHER EAST DURING THE EVENING.
FAVORABLE THERMAL PROFILES AND UNIDIRECTIONAL WIND SHEAR...IN
ADDITION TO DYNAMIC SUPPORT ALOFT...WILL SUPPORT THUNDERSTORMS
WITH THE POTENTIAL FOR DAMAGING WIND GUSTS ON FRI AFTN INTO FRI
NIGHT. PWATS ARE ALSO PROGGED TO REACH 1.50 INCHES WHICH WILL
RESULT IN MODERATE TO HEAVY RAINFALL. THIS SYSTEM BEARS CLOSE
MONITORING SINCE IT IS TOO EARLY TO NARROW DOWN THE FINER DETAILS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
WILL INCREASE POPS QUICKLY FROM WEST TO EAST BY FRIDAY EVENING
INTO SATURDAY MORNING AS THE FRONT MOVES THROUGH. EXPECTING
THE PRECIP TO END ACROSS THE LOCAL AREA SATURDAY AFTERNOON. LOWS
FRIDAY NIGHT MAINLY IN THE 50S. COOLER SATURDAY WITH HIGHS IN THE
60S. HIGH PRESSURE BRIEFLY BUILDS IN SUNDAY FOR DRY WX. THERE IS
THE POSSIBILITY OF INCREASED ONSHORE FLOW NEXT MONDAY WITH A
COASTAL FRONT/INVERTED TROUGH BACKING INTO THE AREA. WILL
ADVERTISE SOME LOW POPS BY NEXT MONDAY FOR NOW AND KEEPS HIGH
TEMPS IN THE 60S NEXT SUNDAY/MONDAY.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
E/SE ONSHORE FLOW PREVAILS EARLY THIS MORNING...WITH VARIABLY
CLOUDY SKIES ACRS THE AREA. IN GENERAL...TAF SITES WILL HAVE
BKN/OVC CIGS 4 TO 7K FT AGL WITH SOME POTENTIAL LOWERING TO MVFR
LEVELS (2-3K FT AGL) BETWEEN 09-12Z. MODELS STRUGGLING TO HANDLE
ONSHORE FLOW AND POSSIBLE IFR CIGS OVER THE REGION. THE HIGHEST
CONFIDENCE FOR IFR CIGS EXPECTED TO REMAIN OVER THE PIEDMONT WWD
INTO THE BLUE RIDGE AND HIGHER TERRAIN (WHICH WOULD NOT AFFECT TAF
SITES). SOME PATCHY FOG WILL BE POSSIBLE INLAND IF SKIES CLEAR
OUT...BUT THIS LOOKS TO BE UNLIKELY AT KRIC SO WILL NOT HAVE ANY
MVFR/IFR VSBYS.
OVERALL CONDITIONS IMPROVE TODAY AS HIGH PRESSURE MOVES BACK INTO
THE REGION THROUGH WED NIGHT. LOW LEVEL MOISTURE WILL BRING AT
LEAST A LOW CHANCE FOR PATCHY FOG/LOW CIGS BY EARLY WED
MORNING...WITH ISOLATED TO WIDELY SCATTERED SHRA/TSRA POSSIBLE WED
LATE AFTN/EARLY EVENING (GREATEST CHC FOR THIS AT KRIC). COULD
AGAIN SEE SOME PATCHY FOG/LOW CLOUDS EARLY THU. OTHERWISE...MAINLY
VFR UNTIL THE FRONT ARRIVES FRI AFTN INTO EARLY SAT...BRINGING
NUMEROUS SHRA/ISOLATED TO SCATTERED TSRA AND A PERIOD OF IFR
CONDITIONS.
&&
.MARINE...
HAVE ADDED A FEW MORE ZONES INTO THE SCA HEADLINES...AS SEAS REMAIN
6-8 FT ACRS SE VA AND NE NC COASTAL WATERS (3-4 FT AT THE MOUTH OF
THE BAY)...AND ARE SLOWLY INCREASING FARTHER NORTH. FOR COASTAL
WATERS N OF PARRAMORE WILL START THE SCA BY 7 AM...AND SEAS SHOULD
AVG 4-6 FT ACRS THESE AREAS THROUGH THE EVENING. WHILE MUCH OF THIS
IS DUE TO SWELL RATHER THAN WIND HAVE DECIDED TO KEEP IT SMALL CRAFT
ADVSY AS OPPOSED TO SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS TO AVOID
CONFUSION W/ MULTIPLE HEADLINES.
OTHERWISE...WEAK LOW PRESSURE IS STILL SITUATED OFF THE SC COAST
WITH HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST AND THE
RESULTANT FLOW BETWEEN THESE TWO FEATURES CONTINUES TO PRODUCE E/SE
WINDS. WIND SPEEDS TODAY ARE NOT EXPECTED TO GET MUCH ABOVE 15 KT SO
DO NOT ANTICIPATE ANY HEADLINES OUTSIDE OF THE COASTAL WATERS AND
MOUTH OF THE BAY FOR TODAY. IT MAY BE CLOSE IN THE BAY BY THIS
EVENING AS SE FLOW INCREASES SOMEWHAT AS IT OFTEN DOES IN THE
EVENING (WHILE THEY WEAKEN OVER LAND). FOR NOW HAVE KEPT THEM CAPPED
AT 15 KT. WINDS WILL THEN TURN MORE TO SW OVERNIGHT BEFORE BECOMING
RATHER LIGHT ON WED. THIS SHOULD ALLOW SEAS TO SUBSIDE BELOW 5 FT.
WINDS INCREASE ON THU...AND ESPECIALLY THU NIGHT THROUGH FRI AS
PRESSURE GRADIENT TIGHTENS UP AHEAD OF THE APPROACHING COLD FRONT.
SCA CONDITIONS ARE LIKELY THU NIGHT THROUGH FRI NIGHT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ634-
654-656-658.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ650-
652.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/JAB
SHORT TERM...BMD
LONG TERM...JDM
AVIATION...LKB
MARINE...LKB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
721 AM EDT TUE APR 16 2013
.AVIATION...
//DISCUSSION...
A COLD FRONT HAS CLEARED THE TAF SITES OVERNIGHT. AN AREA OF SHOWERS
FROM PTK SOUTH TO THE METRO AIRPORTS WILL SLOWLY CLEAR OUT OVER THE
NEXT FEW HOURS...LEAVING LOW LEVEL MOISTURE AND CLOUDS IN PLACE.
BEFORE THE SHOWERS EXIT EAST SOME THUNDERSTORMS ARE POSSIBLE AT THE
METRO AIRPORTS THROUGH 13Z AS LINGERING INSTABILITY CLEARS OUT OF
THE REGION. THE LOW CLOUDS WILL ERODE AS THE DAY WEARS ON AS LOW
LEVEL MOISTURE IS SCOURED OUT BY DRIER AIR ADVECTING IN WITH A RIDGE
OF HIGH PRESSURE. THIS PROCESS IS ALREADY UNDERWAY ACROSS NORTHERN
LOWER MICHIGAN AS CONDITIONS HAVE BECOME VFR. ALTHOUGH MODELS BRING
SHOWERS BACK OVER THE TAF SITES LATE TONIGHT...CONFIDENCE IN SHOWERS
IS NOT HIGH ENOUGH TO PUT INTO THE TAFS AT THIS POINT.
FOR DTW...THUNDERSTORMS SHOULD CLEAR THE AIRPORT AROUND 13Z WITH
LINGERING SHOWERS THROUGH 15Z AS THE COLD FRONT CONTINUES MARCHING
SOUTHEAST.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE THUNDERSTORMS WILL OCCUR EARLY THIS MORNING.
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT THIS MORNING.
&&
.PREV DISCUSSION...ISSUED 613 AM EDT TUE APR 16 2013
UPDATE...
LOW LEVEL FGEN...NOT PICKED UP BY THE 00Z MODELS...WAS PICKED UP
BY THE 06Z MODELS AND CENTERED AROUND H9. DESPITE PICKING THIS LOW
LEVEL FGEN UP THE NWP MODELS CONTINUE TO UNDERESTIMATE THE CURRENT
ACTIVITY ABOUT TO SWEEP THROUGH EXTREME SOUTHEASTERN MICHIGAN.
HOWEVER THE RECENT 3KM HRRR MODEL PICKS THIS UP NICELY AND SWEEPS
THE MODERATE SHOWERS THROUGH THE AREA BETWEEN 10-13Z THIS MORNING.
WITH MODEST INSTABILITY AND INTERSPERSED LIGHTNING STRIKES WILL
ADD THUNDER TO THE MUCH RAISED POPS ACROSS THE SOUTHERN CWA THIS
MORNING AS THE COLD FRONT CONTINUES MARCHING SOUTHEASTWARD. AT
THIS TIME THE REST OF THE FORECAST LOOKS FINE GOING FORWARD AS THE
ACTIVITY TO THE NORTH HAS SIGNIFICANTLY DECREASED AS ADVERTISED.
PREV DISCUSSION...ISSUED 334 AM EDT TUE APR 16 2013
SHORT TERM...THIS MORNING THROUGH TONIGHT
AN AREA OF SHOWERS STRETCHING FROM CENTRAL LAKE HURON BACK TO
SOUTHERN LAKE MICHIGAN ALONG A SLOWLY MOVING COLD FRONT AND
COINCIDENT WITH FGEN IN THE H9-H7 LAYER WILL SLOWLY MOVE SOUTHEAST
DURING THE MORNING HOURS. HOWEVER MODEL CROSS SECTIONS SHOW THE FGEN
WILL ELONGATE...WEAKEN AND LIFT NORTH AS THE MORNING WEARS ON. DEEP
MOISTURE ASSOCIATED WITH THE FRONT WILL LIFT NORTH WITH THE MAIN
FGEN BAND...AS THE FRONT ITSELF BECOMES DIFFUSE TEMPERATURE-WISE.
THESE FACTORS DO NOT LEAD TO A HIGH DEGREE OF CONFIDENCE THAT RAIN
SHOWERS WILL ACTUALLY MAKE IT ALL THE WAY THROUGH THE SOUTHERN AND
EASTERN CWA THIS MORNING AS THE FRONT TRACKS TOWARDS THE NORTHERN
OHIO VALLEY. GIVEN THE WEAKENING DYNAMICS AND DECREASED AVAILABLE
MOISTURE WILL NOT DRAG THE CATEGORICAL POPS ALL THE THROUGH THE
SOUTHEASTERN CWA THIS MORNING AS THE FRONT MOVES SOUTH...AND INSTEAD
LEAVE LIKELY POPS ACROSS THESE AREAS PER THE PREVIOUS FORECAST. WITH
THE FRONT OVER THE NORTHERN OHIO VALLEY POPS WILL BE RATHER LOW THIS
AFTERNOON AND THIS EVENING AS THE MAIN DYNAMICS STAY TO THE SOUTH.
WITH A BETTER HANDLE ON THE PLACEMENT OF THE FRONT WILL TAKE THE
CHANCY POPS FROM THE AFTERNOON AND PLACE THEM IN THE EVENING HOURS
AS THE SURGE NORTHWARD OF THE MID-LEVEL FRONT AND INCREASED FGEN
OVER THE SOUTHERN GREAT LAKES DOES NOT MAKE IT INTO THE SOUTHEASTERN
MICHIGAN UNTIL LATER TONIGHT. THEREFORE WILL REFINE THE WINDOW FOR
LIKELY POPS TO AFTER MIDNIGHT WHEN THIS BETTER FORCING COMES BACK
INTO THE CWA. WITH MEAGER DYNAMICS AND NOT MUCH INSTABILITY TO SPEAK
OF WILL CONTINUE TO LEAVE THUNDER OUT OF THE FORECAST THROUGH
TONIGHT.
WITH THE PUSH OF COLD AIR BEHIND THE COLD FRONT BECOMING MORE
DIFFUSE...HIGH TEMPERATURES TODAY SHOULD BE ABLE TO GET INTO THE
UPPER 50S TO LOWER 60S. NORTHEAST WINDS OVERNIGHT WILL BRING COOLER
AIR IN FROM THE GREAT LAKES...WITH LOWS RANGING FROM THE MID 30S
ACROSS THE NORTH TO THE LOW TO MID 40S ACROSS THE SOUTH.
LONG TERM...
HIGHLY AMPLIFIED PATTERN DEVELOPING...AS UPPER LEVEL ENERGY OVER
PACIFIC NORTHWEST EXTENDING SOUTH INTO THE GREAT BASIN CONTINUES TO
CONSOLIDATE AND ORGANIZE. THE 00Z MODEL TRENDS ARE DEEPER WITH THE
SYSTEM COMING OUT OF THE CENTRAL CONUS/MIDWEST THURSDAY...AND IT NOW
APPEARS FRIDAY MORNING WILL BE MILD AND RAINY BEFORE THE STRONG LOW
LEVEL COLD ADVECTION SENDS 850 MB TEMPS BELOW ZERO BY 00Z SATURDAY.
THURSDAY/THURSDAY NIGHT LOOKS VERY WET ...AS IMPRESSIVE LOW LEVEL
JET (50 TO 55 KNOTS AT 850 MB) EXTENDS FROM TEXAS ALL THE WAY UP TO
THE CENTRAL GREAT LAKES...ALLOWING COPIOUS AMOUNTS OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. STILL HAVE SOME CONCERN FOR SEVERE
WEATHER ON THURSDAY WITH THE IMPRESSIVE WIND FIELDS...AS 00Z GFS
EVEN ADVERTISING SURFACE BASED CAPES IN SOLIDLY EXCESS OF 1000 J/KG
THERE IS A STRONG POSSIBILITY A FLOOD WATCH WILL BE NEEDED FOR
THURSDAY-FRIDAY MORNING TIME FRAME AS THIS DYNAMIC SYSTEM AND
MOISTURE LADEN (PW VALUES TO AROUND 1.5 INCHES) IMPACTS THE GREAT
LAKES REGION. THE FORECAST IS COMPLICATED ON THURSDAY DUE TO THE
FACT RIGHT ENTRANCE REGION FORCING OF THE UPPER LEVEL JET IS
DISPLACED WELL TO THE NORTH OF LOWER MICHIGAN...SO NOT A GUARANTEE
IS GOING TO RAIN ACROSS THE FAR SOUTHEAST AS WE REMAIN UNDER THE
INFLUENCE OF THE DEPARTING UPPER LEVEL RIDGE. ON THE FLIP SIDE...IF
THE ALL BLEND SURFACE DEW PTS OF 62-63 DEGREES VERIFY...THAT IS
CLIMATOLOGY NEAR RECORD TERRITORY...AND HARD TO BELIEVE THE ENHANCED
ISENTROPIC ASSENT WILL NOT GENERATE SHOWERS AND THUNDERSTORMS WITH
THE MORE THAN ADEQUATE INSTABILITY.
NEED TO MENTION THE POTENTIAL FOR STRONG WIND POP RIGHT BEHIND THE
POWERFUL COLD FRONT ON FRIDAY...AS 6 HR RISE/FALL PRESSURE COUPLET
IS INTENSIFYING THROUGH THE DAY...AND LOOKS TO BE AT LEAST 20 MB.
WITH THE STOUT LOW LEVEL COLD ADVECTION/SUBSIDENCE COMING THROUGH
DURING THE PEAK HEATING OF THE DAY...MIXING INTO THE 45 TO 50 KNOT
WINDS AT 850 MB DOES NOT LOOK TO BE MUCH OF A CHALLENGE...AND WILL
HIGHLIGHT THE POTENTIAL OF WIND GUSTS OF 45 MPH OR GREATER IN HWO.
QUIET BY COOL WEATHER FOR THE WEEKEND...AS 850 MB TEMPS STILL
PROGGED TO BE RUNNING AROUND -10 C TO START THE DAY ON
SATURDAY...BUT MODIFYING INTO THE MID SINGLE NUMBERS DURING THE
AFTERNOON...AND NEGATIVE LOW SINGLE NUMBERS FOR SUNDAY
AFTERNOON...PER 00Z EURO.
MARINE...
A SLOWLY MOVING COLD FRONT WILL FLIP THE WIND DIRECTION TO WNW
ACROSS ALL OF THE CENTRAL GREAT LAKES REGION THIS MORNING. WINDS
WILL THEN VEER TO THE NORTHEAST TONIGHT THEN TO AN EASTERLY
DIRECTION ON WEDNESDAY. HOWEVER SHORT DURATION FETCH AND A LACK OF
STRONGER WINDS WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS
ACROSS AREA WATERS THROUGH WEDNESDAY. PERSISTENT EASTERLY FLOW WILL
LEAD TO A BUILD UP OF WAVES ACROSS THE CENTRAL GREAT LAKES WEDNESDAY
NIGHT...WITH SMALL CRAFT HEADLINES A POSSIBILITY FOR ALL NEARSHORE
AREAS SAVE FOR INNER SAGINAW BAY. WILL ISSUE APPROPRIATE HEADLINES
AS NECESSARY AS THE EVENT DRAWS CLOSER.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....KURIMSKI
UPDATE.......KURIMSKI
SHORT TERM...KURIMSKI
LONG TERM....SF
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
613 AM EDT TUE APR 16 2013
.UPDATE...
LOW LEVEL FGEN...NOT PICKED UP BY THE 00Z MODELS...WAS PICKED UP
BY THE 06Z MODELS AND CENTERED AROUND H9. DESPITE PICKING THIS LOW
LEVEL FGEN UP THE NWP MODELS CONTINUE TO UNDERESTIMATE THE CURRENT
ACTIVITY ABOUT TO SWEEP THROUGH EXTREME SOUTHEASTERN MICHIGAN.
HOWEVER THE RECENT 3KM HRRR MODEL PICKS THIS UP NICELY AND SWEEPS
THE MODERATE SHOWERS THROUGH THE AREA BETWEEN 10-13Z THIS MORNING.
WITH MODEST INSTABILITY AND INTERSPERSED LIGHTNING STRIKES WILL
ADD THUNDER TO THE MUCH RAISED POPS ACROSS THE SOUTHERN CWA THIS
MORNING AS THE COLD FRONT CONTINUES MARCHING SOUTHEASTWARD. AT
THIS TIME THE REST OF THE FORECAST LOOKS FINE GOING FORWARD AS THE
ACTIVITY TO THE NORTH HAS SIGNIFICANTLY DECREASED AS ADVERTISED.
&&
.PREV DISCUSSION...ISSUED 334 AM EDT TUE APR 16 2013
SHORT TERM...THIS MORNING THROUGH TONIGHT
AN AREA OF SHOWERS STRETCHING FROM CENTRAL LAKE HURON BACK TO
SOUTHERN LAKE MICHIGAN ALONG A SLOWLY MOVING COLD FRONT AND
COINCIDENT WITH FGEN IN THE H9-H7 LAYER WILL SLOWLY MOVE SOUTHEAST
DURING THE MORNING HOURS. HOWEVER MODEL CROSS SECTIONS SHOW THE FGEN
WILL ELONGATE...WEAKEN AND LIFT NORTH AS THE MORNING WEARS ON. DEEP
MOISTURE ASSOCIATED WITH THE FRONT WILL LIFT NORTH WITH THE MAIN
FGEN BAND...AS THE FRONT ITSELF BECOMES DIFFUSE TEMPERATURE-WISE.
THESE FACTORS DO NOT LEAD TO A HIGH DEGREE OF CONFIDENCE THAT RAIN
SHOWERS WILL ACTUALLY MAKE IT ALL THE WAY THROUGH THE SOUTHERN AND
EASTERN CWA THIS MORNING AS THE FRONT TRACKS TOWARDS THE NORTHERN
OHIO VALLEY. GIVEN THE WEAKENING DYNAMICS AND DECREASED AVAILABLE
MOISTURE WILL NOT DRAG THE CATEGORICAL POPS ALL THE THROUGH THE
SOUTHEASTERN CWA THIS MORNING AS THE FRONT MOVES SOUTH...AND INSTEAD
LEAVE LIKELY POPS ACROSS THESE AREAS PER THE PREVIOUS FORECAST. WITH
THE FRONT OVER THE NORTHERN OHIO VALLEY POPS WILL BE RATHER LOW THIS
AFTERNOON AND THIS EVENING AS THE MAIN DYNAMICS STAY TO THE SOUTH.
WITH A BETTER HANDLE ON THE PLACEMENT OF THE FRONT WILL TAKE THE
CHANCY POPS FROM THE AFTERNOON AND PLACE THEM IN THE EVENING HOURS
AS THE SURGE NORTHWARD OF THE MID-LEVEL FRONT AND INCREASED FGEN
OVER THE SOUTHERN GREAT LAKES DOES NOT MAKE IT INTO THE SOUTHEASTERN
MICHIGAN UNTIL LATER TONIGHT. THEREFORE WILL REFINE THE WINDOW FOR
LIKELY POPS TO AFTER MIDNIGHT WHEN THIS BETTER FORCING COMES BACK
INTO THE CWA. WITH MEAGER DYNAMICS AND NOT MUCH INSTABILITY TO SPEAK
OF WILL CONTINUE TO LEAVE THUNDER OUT OF THE FORECAST THROUGH
TONIGHT.
WITH THE PUSH OF COLD AIR BEHIND THE COLD FRONT BECOMING MORE
DIFFUSE...HIGH TEMPERATURES TODAY SHOULD BE ABLE TO GET INTO THE
UPPER 50S TO LOWER 60S. NORTHEAST WINDS OVERNIGHT WILL BRING COOLER
AIR IN FROM THE GREAT LAKES...WITH LOWS RANGING FROM THE MID 30S
ACROSS THE NORTH TO THE LOW TO MID 40S ACROSS THE SOUTH.
LONG TERM...
HIGHLY AMPLIFIED PATTERN DEVELOPING...AS UPPER LEVEL ENERGY OVER
PACIFIC NORTHWEST EXTENDING SOUTH INTO THE GREAT BASIN CONTINUES TO
CONSOLIDATE AND ORGANIZE. THE 00Z MODEL TRENDS ARE DEEPER WITH THE
SYSTEM COMING OUT OF THE CENTRAL CONUS/MIDWEST THURSDAY...AND IT NOW
APPEARS FRIDAY MORNING WILL BE MILD AND RAINY BEFORE THE STRONG LOW
LEVEL COLD ADVECTION SENDS 850 MB TEMPS BELOW ZERO BY 00Z SATURDAY.
THURSDAY/THURSDAY NIGHT LOOKS VERY WET ...AS IMPRESSIVE LOW LEVEL
JET (50 TO 55 KNOTS AT 850 MB) EXTENDS FROM TEXAS ALL THE WAY UP TO
THE CENTRAL GREAT LAKES...ALLOWING COPIOUS AMOUNTS OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. STILL HAVE SOME CONCERN FOR SEVERE
WEATHER ON THURSDAY WITH THE IMPRESSIVE WIND FIELDS...AS 00Z GFS
EVEN ADVERTISING SURFACE BASED CAPES IN SOLIDLY EXCESS OF 1000 J/KG
THERE IS A STRONG POSSIBILITY A FLOOD WATCH WILL BE NEEDED FOR
THURSDAY-FRIDAY MORNING TIME FRAME AS THIS DYNAMIC SYSTEM AND
MOISTURE LADEN (PW VALUES TO AROUND 1.5 INCHES) IMPACTS THE GREAT
LAKES REGION. THE FORECAST IS COMPLICATED ON THURSDAY DUE TO THE
FACT RIGHT ENTRANCE REGION FORCING OF THE UPPER LEVEL JET IS
DISPLACED WELL TO THE NORTH OF LOWER MICHIGAN...SO NOT A GUARANTEE
IS GOING TO RAIN ACROSS THE FAR SOUTHEAST AS WE REMAIN UNDER THE
INFLUENCE OF THE DEPARTING UPPER LEVEL RIDGE. ON THE FLIP SIDE...IF
THE ALL BLEND SURFACE DEW PTS OF 62-63 DEGREES VERIFY...THAT IS
CLIMATOLOGY NEAR RECORD TERRITORY...AND HARD TO BELIEVE THE ENHANCED
ISENTROPIC ASSENT WILL NOT GENERATE SHOWERS AND THUNDERSTORMS WITH
THE MORE THAN ADEQUATE INSTABILITY.
NEED TO MENTION THE POTENTIAL FOR STRONG WIND POP RIGHT BEHIND THE
POWERFUL COLD FRONT ON FRIDAY...AS 6 HR RISE/FALL PRESSURE COUPLET
IS INTENSIFYING THROUGH THE DAY...AND LOOKS TO BE AT LEAST 20 MB.
WITH THE STOUT LOW LEVEL COLD ADVECTION/SUBSIDENCE COMING THROUGH
DURING THE PEAK HEATING OF THE DAY...MIXING INTO THE 45 TO 50 KNOT
WINDS AT 850 MB DOES NOT LOOK TO BE MUCH OF A CHALLENGE...AND WILL
HIGHLIGHT THE POTENTIAL OF WIND GUSTS OF 45 MPH OR GREATER IN HWO.
QUIET BY COOL WEATHER FOR THE WEEKEND...AS 850 MB TEMPS STILL
PROGGED TO BE RUNNING AROUND -10 C TO START THE DAY ON
SATURDAY...BUT MODIFYING INTO THE MID SINGLE NUMBERS DURING THE
AFTERNOON...AND NEGATIVE LOW SINGLE NUMBERS FOR SUNDAY
AFTERNOON...PER 00Z EURO.
MARINE...
A SLOWLY MOVING COLD FRONT WILL FLIP THE WIND DIRECTION TO WNW
ACROSS ALL OF THE CENTRAL GREAT LAKES REGION THIS MORNING. WINDS
WILL THEN VEER TO THE NORTHEAST TONIGHT THEN TO AN EASTERLY
DIRECTION ON WEDNESDAY. HOWEVER SHORT DURATION FETCH AND A LACK OF
STRONGER WINDS WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS
ACROSS AREA WATERS THROUGH WEDNESDAY. PERSISTENT EASTERLY FLOW WILL
LEAD TO A BUILD UP OF WAVES ACROSS THE CENTRAL GREAT LAKES WEDNESDAY
NIGHT...WITH SMALL CRAFT HEADLINES A POSSIBILITY FOR ALL NEARSHORE
AREAS SAVE FOR INNER SAGINAW BAY. WILL ISSUE APPROPRIATE HEADLINES
AS NECESSARY AS THE EVENT DRAWS CLOSER.
&&
.AVIATION...ISSUED 1149 PM EDT MON APR 15 2013
//DISCUSSION...
A COLD FRONT NOW OVER MBS WILL SLOWLY ADVANCE ACROSS SE MI EARLY
THIS MORNING...PASSING THROUGH METRO DETROIT AROUND 09Z. A REGION OF
SHOWERS WILL OCCUR ALONG AND IN THE WAKE OF THIS COLD FRONT. THE
ADDED LOW LEVEL MOISTURE WILL RAPIDLY LOWER CEILINGS TO MVFR WITH
SOME IFR CONDITIONS POSSIBLE IN THE IMMEDIATE POST FRONTAL AIRMASS.
THE FRONTAL PASSAGE WILL ALSO BE MARKED BY AN ABRUPT SHIFT IN THE
WINDS TO THE W-NW. CONDITIONS ARE EXPECTED TO IMPROVE MARKEDLY LATE
TUES MORNING AS DRY AIR FUNNELS IN FROM THE WEST.
FOR DTW...MORE SIGNIFICANT LOWERING OF CEILINGS AND SHOWERS WILL
HOLD OFF UNTIL 09 TO 11Z GIVEN THE LATE ARRIVAL OF THE COLD FRONT.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE CEILINGS WILL BE BELOW 5000 FT TUESDAY MORNING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
UPDATE.......KURIMSKI
AVIATION.....SC
SHORT TERM...KURIMSKI
LONG TERM....SF
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BUFFALO NY
1104 AM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY ALONG WITH SOME SHOWERS...
WITH A THUNDERSTORM ALSO POSSIBLE SOUTH OF BUFFALO AND ROCHESTER.
FOLLOWING THE FRONT...SEASONABLY COOLER WEATHER WILL RETURN FOR
TONIGHT AND WEDNESDAY...BEFORE MUCH WARMER AIR SURGES BACK INTO THE
REGION IN TIME FOR THURSDAY ALONG WITH THE CHANCE FOR SOME
ADDITIONAL SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...LOW PRESSURE WILL TRACK ACROSS
CENTRAL QUEBEC PROVENCE AND RAPIDLY EJECT NORTHEASTWARD TO
LABRADOR...AND IN THE PROCESS WILL SLOWLY PUSH ITS TRAILING COLD
FRONT SOUTHEASTWARD ACROSS NEW YORK STATE. AT 1100 AM...THIS FRONT
WAS JUST NORTHWEST OF LAKE ERIE AND ONTARIO...WITH GOOD MODEL
AGREEMENT THAT THE FRONT WILL MOVE ACROSS WESTERN NEW YORK THIS
AFTERNOON.
RADAR SHOWS SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OUT AHEAD OF
THIS FRONTAL BOUNDARY...WITH STEADY SHOWERS ACROSS MOST OF NEW
YORK WEST OF ROCHESTER. WHILE SOME OF THE 00Z/06 GUIDANCE
STRUGGLED TO FORECAST EXACTLY WHERE CONVECTION WOULD BREAK
OUT...THE LATEST RUNS OF THE HRRR DEPICT CURRENT CONDITIONS
FAIRLY WELL...AND THUS PROVIDES FAIRLY GOOD GUIDANCE FOR THE
REMAINDER OF THE DAY. FOLLOWING THIS...EXPECT SHOWERS TO CONTINUE
TO MOVE RAPIDLY ENE...BRINGING AT LEAST SOME PRECIPITATION TO
NEARLY ALL OF THE REGION THROUGH EARLY AFTERNOON. HEAVIEST SHOWERS
WILL BE SOUTH...WHERE THERE STILL ARE QUITE A FEW LIGHTNING
STRIKES. THIS AREA SHOULD MOVE THROUGH RATHER RAPIDLY...BUT THE
HRRR (NOW WITH SUPPORT FROM THE 12Z NAM) SUGGESTS THAT ANOTHER
ROUND OF SHOWERS AND POSSIBLY THUNDERSTORMS WILL DEVELOP RIGHT ON
THE FRONT. TO DO THIS WILL TAKE A MODEST CONTRIBUTION FROM DAYTIME
HEATING ACROSS THE FINGER LAKES AND EASTERN LAKE ONTARIO
REGIONS...EXTENDING INTO CENTRAL PORTIONS OF THE STATE. IF THIS
DOES OCCUR...THIS WILL NOT DEVELOP UPSTREAM...RATHER SHOWERS WOULD
DEVELOP ACROSS THE ABOVE MENTIONED REGIONS LATE THIS AFTERNOON.
QPFS WILL VARY...WITH MOST AREAS LIKELY TO SEE A TENTH OF AN INCH
OR TWO...WITH LOCALLY HIGHER AMOUNTS TO A HALF INCH IN
THUNDERSTORMS.
OTHERWISE...THE DAY WILL GET OFF TO A WARM AND BREEZY START.
TEMPERATURES WILL REMAIN IN THE 60S AHEAD OF THE RAIN
SHOWERS...WITH HIGHS IN THE UPPER 60S LIKELY IN THE FINGER LAKES
REGION WHERE RAIN WILL HOLD OFF A BIT LONGER. MEANWHILE...SOUTHERLY
WINDS WILL CONTINUE TO GUST TO 30 TO 35 MPH IN MOST
LOCATIONS...WITH GUSTS TO 40 MPH ACROSS HIGHER TERRAIN AND IN THE
BLACK RIVER VALLEY.
LATE THIS AFTERNOON THROUGH TONIGHT...THE FRONTAL BOUNDARY WILL GET
SUPPRESSED FURTHER SOUTH TO THE MASON/DIXON LINE AS HIGH PRESSURE
AND MUCH DRIER AIR BRIEFLY RIDGES SOUTHEAST FROM NORTHERN ONTARIO
PROVINCE. FOR OUR AREA...THIS WILL RESULT IN ANY LINGERING SHOWER
CHANCES ENDING FROM NORTHWEST TO SOUTHEAST LATE THIS AFTERNOON AND
EVENING FOLLOWED BY DRY WEATHER THE REMAINDER OF THE NIGHT...THOUGH
SOME CLOUDS WILL LINGER ACROSS AREAS SOUTH OF LAKE ONTARIO...WHICH
WILL BE CLOSER TO THE SLOWLY DEPARTING FRONTAL ZONE. AS FOR TEMPS...
COOLER AIR FILTERING IN BEHIND THE FRONT WILL RESULT IN TEMPS
FALLING BACK TO THE UPPER 30S TO LOWER 40S SOUTH OF LAKE ONTARIO...
AND TO THE LOWER-MID 30S ACROSS THE NORTH COUNTRY WHERE THERE WILL
BE LESS CLOUD COVER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
A PROGRESSIVE HIGH AMPLITUDE FLOW WILL BE FOUND ACROSS THE UNITED
STATES DURING THIS PERIOD...WITH THE LOWER GREAT LAKES REGION BEING
FORTUNATE ENOUGH TO BE FOUND ON THE WARM SIDE OF AN EXPANSIVE RIDGE.
THIS WILL LEAD TO SEASONABLE CONDITIONS ON WEDNESDAY BEFORE
ANOMALOUS WARMTH RETURNS FOR THURSDAY AND FRIDAY. TEMPERATURES AT
THAT TIME COULD EASILY CLIMB TO MORE THAN 20 DEGREES F ABOVE NORMAL
VALUES. IT IS NOT OUT OF THE QUESTION THAT THE WARMER VALLEYS COULD
EVEN TICKLE THE 80 DEGREE MARK ON THURSDAY.
IN TERMS OF PCPN...THE BULK OF THIS PERIOD WILL BE RAIN-FREE. WHILE
THERE WILL BE THE CHANCE FOR SOME NUISANCE LIGHT SHOWERS AS THE
WARMER AIR WORKS INTO OUR REGION WEDNESDAY NIGHT AND THURSDAY...THE
HIGHEST CHANCE FOR ANY ADVERSE WEATHER WILL COME FRIDAY AFTERNOON
AND NIGHT WHEN A STRONG COLD FRONT WILL PLOW ACROSS THE LOWER GREAT
LAKES. THIS FEATURE COULD END UP GENERATING OUR FIRST WIDESPREAD
SEVERE WEATHER OUTBREAK. SOME DETAILS...
HIGH PRESSURE CENTERED OVER NORTHERN ONTARIO ON WEDNESDAY WILL ARCH
ACROSS THE LOWER GREAT LAKES AND NEW ENGLAND TO PROVIDE US WITH FAIR
SEASONABLE CONDITIONS. THE SUNNIEST CONDITIONS WILL BE FOUND ACROSS
THE EASTERN LAKE ONTARIO REGION WHILE SOME HIGH AND MID LEVEL CLOUDS
CAN BE EXPECTED OVER THE FAR WESTERN COUNTIES. GIVEN THE LIGHT
NORTHERLY FLOW...THE COOLEST WEATHER WILL LIKELY BE FOUND OVER THE
COUNTIES BORDERING THE SOUTH SHORE OF LK ONTARIO WHERE READINGS WILL
STRUGGLE INTO THE LOW 50S. ELSEWHERE...HIGHS SHOULD BE CLOSE TO
THEIR SEASONABLE NORMS OF 55 TO 60.
AS THE LARGE SFC HIGH MOVES EAST ACROSS QUEBEC WEDNESDAY NIGHT...A
DEEP INVERTED TROUGH WILL EXTEND FROM THE CENTRAL PLAINS NORTHEAST
ACROSS THE UPPER GREAT LAKES. A DEEP SOUTHERLY FLOW WILL DEVELOP
BETWEEN THESE SYSTEMS...WITH STRONG WARM ADVECTION FOUND OVER THE
GREAT LAKES REGION. THE LEADING EDGE OF THE WARMER AIRMASS (WARM
FRONT) MAY GENERATE SOME LIGHT SHOWERS/SPRINKLES ACROSS OUR FORECAST
AREA IN THE PROCESS...WITH MORE WIDESPREAD SHRA/TSRA REMAINING OVER
UPPER ONTARIO AND THE UPPER GREAT LAKES.
THE SOUTHERLY FLOW WILL INTENSIFY OVER THE LOWER GREAT LAKES AND
OHIO VALLEY ON THURSDAY AS THE AFOREMENTIONED WARM FRONT WILL LIFT
FROM THE THOUSAND ISLANDS REGION TO SOUTHERN QUEBEC. THIS WILL ALLOW
OUR SKIES TO PARTIALLY CLEAR DURING THE COURSE OF THURSDAY...MUCH
LIKE THEY DID YESTERDAY (MONDAY) WHEN TEMPERATURES REACHED INTO THE
70S. SPEAKING OF WHICH...H85 TEMPS WILL JUMP TO AROUND 14C BY
THURSDAY AFTERNOON AND THIS WILL EASILY SUPPORT DAYTIME HIGHS IN THE
MID 70S WITH 80 DEGREE READINGS NOT OUT OF THE QUESTION IN THE
WARMER VALLEYS.
WARM AND BREEZY CONDITIONS WILL THEN BE FOUND ACROSS THE FORECAST
AREA THURSDAY NIGHT AS DEEPENING LOW PRESSURE WILL LIFT TO LOWER
MICHIGAN WHILE SWEEPING A STRONG COLD FRONT AND ITS ASSOCIATED
SEVERE WEATHER ACROSS THE OHIO AND TENNESSEE VALLEYS. FOR OUR REGION
THOUGH...WE SHOULD BE MAINLY DRY AND QUITE MILD WITH TEMPERATURES
HAVING TROUBLE FALLING BELOW 60. IT WILL BE A LITTLE ON THE HUMID
SIDE AS WELL...MAKING IT FEEL MORE LIKE A NIGHT IN MID-LATE JUNE.
FRIDAY WILL FEATURE VERY UNSETTLED WEATHER AS THE DEEP SFC LOW
TO OUR WEST WILL PUSH ITS STRONG COLD FRONT ACROSS MUCH OF OUR
REGION. FROM THIS VANTAGE POINT...GUIDANCE HAS BEEN CONSISTENT WITH
BRINGING THE FRONT ACROSS WESTERN NEW YORK DURING THE AFTERNOON AND
EVENING. IF THIS TIMING HOLDS UP...TEMPERATURES SHOULD BE ABLE TO
JUMP BACK INTO THE 70S BEFORE THE THICKER CLOUD COVER AND FRONTAL
PCPN MOVES IN. SPEAKING OF WHICH...GIVEN THE STRONG DYNAMICS OF THE
SYNOPTIC SYSTEM AND THE PRESENCE OF A 60-70KT LOW LEVEL JET...WOULD
ANTICIPATE AT LEAST THE THREAT FOR STRONG TO SEVERE THUNDERSTORMS
AHEAD/DURING THE FRONTAL PASSAGE. WHILE GUIDANCE IS NOT DEPICTING
SIGNIFICANT INSTABILITY...CONVECTION COULD EASILY BE SUPPORTED BY
THE STRENGTH OF THE UNDERLYING SYNOPTICS. THE WIND PROFILE AHEAD OF
THE FRONT DEPICTS ALOT OF SHEAR AS WELL...SO THIS IS A VALID
CONCERN. WILL MENTION THIS THREAT IN THE HAZARDOUS WEATHER OUTLOOK.
AS IF THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS IS NOT
ENOUGH...THE STRONG LOW LEVEL JET AND FAVORABLE TRACK OF THE DEEP
SFC LOW FROM LOWER MICHIGAN AND LAKE HURON TO SOUTHERN QUEBEC WILL
SET THE STAGE FOR A SYNOPTIC WIND EVENT. ADVISORY CRITERIA SOUTHERLY
WINDS WILL BE POSSIBLE AHEAD OF THE FRONT ACROSS THE HIGHER
TERRAIN...THEN IN THE WAKE OF THE FRONT...THERE WILL BE AN 8 HOUR
PERIOD WHERE SOUTHWEST WINDS WITHIN THE COLD ADVECTION COULD PRODUCE
SFC WIND GUSTS IN EXCESS OF 50 MPH DOWNWIND OF LK ERIE LATE FRIDAY
AFTERNOON AND THE FIRST HALF OF FRIDAY NIGHT. STAY TUNED.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NOTABLY COOLER WEATHER WILL CHARACTERIZE THIS PERIOD AS SEASONABLY
COOL AIR WILL ACCOMPANY EXPANSIVE HIGH PRESSURE FROM THE NORTHERN
PLAINS.
ON SATURDAY...HIGH PRESSURE WILL GRADUALLY BUILD ACROSS THE UPPER
GREAT LAKES WHILE A DEEP STORM SYSTEM WILL DRIFT TO COASTAL QUEBEC.
THIS WILL KEEP A RELATIVELY TIGHT PRESSURE GRADIENT ACROSS OUR
REGION SO THE STRONG WINDS FROM FRIDAY NIGHT WILL ONLY SLOWLY
SUBSIDE DURING THE COURSE OF SATURDAY. THE GUSTY WINDS AND MUCH
COOLER AIRMASS WILL MAKE FOR A CHILLY DAY AS TEMPS WILL STRUGGLE TO
CLIMB INTO THE MID TO UPPER 40S. THERE COULD ALSO BE A COUPLE
LEFTOVER SHOWERS THROUGH MIDDAY...MAINLY FOR SITES EAST OF
ROCHESTER.
THE EXPANSIVE SFC HIGH WILL BUILD ACROSS OUR REGION SATURDAY NIGHT
AND SUNDAY. THIS WILL PROVIDE US WITH MAINLY CLEAR SKIES FOR THE
SECOND HALF OF THE WEEKEND...ALTHOUGH TEMPERATURES WILL STILL BE
SOME 5 TO 10 DEG F BELOW NORMAL. THE CHILL WILL BE TEMPERED ON
SUNDAY THOUGH WITH AMPLE SUNSHINE.
FOR MONDAY...THE CENTER OF THE SFC HIGH WILL MOVE TO THE CANADIAN
MARITIMES. THE RETURN FLOW AROUND THE HIGH WILL PROMOTE SOME WEAK
WARM ADVECTION OVER THE LOWER GREAT LAKES SO THAT TEMPERATURES WILL
CLIMB BACK TO NEAR NORMAL LEVELS FOR MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THROUGH 15Z...AN INITIAL AREA OF SHOWERS WILL MOVE ACROSS THE
REGION THROUGH 18Z...WITH THIS LIKELY TO LOWER CONDITIONS TO MVFR
IN LOWER CIGS. THE FRONT WILL FOLLOW THIS...POSSIBLY SPARKING
ANOTHER ROUND OF SHOWERS. EXPECT MVFR CONDITIONS TO PERSIST UNTIL
BEHIND THE FRONT WHEN DRIER AIR BUILDS IN THIS EVENING. THERE IS A
CONTINUED CHANCE FOR THUNDERSTORMS THROUGH THIS AFTERNOON...MAINLY
TO THE SOUTH NEAR JHW...HOWEVER AN ISOLATED TSTM CANNOT COMPLETELY
BE RULED OUT AT ANY LOCATION.
DRIER AIR WILL CONTINUE TO BUILD IN OVERNIGHT...WITH VFR
CONDITIONS EXPECTED.
OUTLOOK...
WEDNESDAY...MAINLY VFR.
WEDNESDAY NIGHT AND THURSDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
FRIDAY...DETERIORATION TO MVFR WITH SHOWERS BECOMING LIKELY ALONG
WITH A CHANCE OF THUNDERSTORMS...SOME OF WHICH COULD PRODUCE GUSTY
WINDS.
SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
IN ADVANCE OF A COLD FRONT...SOUTHERLY WINDS TO 15 TO 25 KNOTS
WILL AFFECT EASTERN PORTIONS OF LAKE ERIE AND ONTARIO THIS
MORNING...FOR WHICH SMALL CRAFT ADVISORIES WILL BE IN PLACE.
FOLLOWING THE FRONTAL PASSAGE...WINDS WILL VEER TO WESTERLY AND
DIMINISH THIS AFTERNOON... THEN WILL BECOME RELATIVELY LIGHT FOR
TONIGHT AND WEDNESDAY AS HIGH PRESSURE BRIEFLY NOSES SOUTHEASTWARD
ACROSS THE REGION.
IT SHOULD ALSO BE NOTED THAT WHILE THE FRONT WILL MAINLY JUST
PRODUCE SOME SHOWERS TODAY...A THUNDERSTORM OR TWO WILL ALSO BE
POSSIBLE ACROSS LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON
FOR LOZ044-045.
&&
$$
SYNOPSIS...JJR
NEAR TERM...APFFEL/JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...APFFEL/JJR
MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS BUFFALO NY
946 AM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY ALONG WITH SOME SHOWERS...
WITH A THUNDERSTORM ALSO POSSIBLE SOUTH OF BUFFALO AND ROCHESTER.
FOLLOWING THE FRONT...SEASONABLY COOLER WEATHER WILL RETURN FOR
TONIGHT AND WEDNESDAY...BEFORE MUCH WARMER AIR SURGES BACK INTO THE
REGION IN TIME FOR THURSDAY ALONG WITH THE CHANCE FOR SOME
ADDITIONAL SHOWERS.
&&
.NEAR TERM /THROUGH TONIGHT/...
DURING THE COURSE OF TODAY...LOW PRESSURE OVER CENTRAL ONTARIO
PROVINCE WILL RAPIDLY EJECT NORTHEASTWARD TO LABRADOR...AND IN THE
PROCESS WILL SLOWLY PUSH ITS TRAILING COLD FRONT SOUTHEASTWARD
ACROSS NEW YORK STATE. AT 900 AM...THIS FRONT WAS LOCATED BETWEEN
LAKE HURON AND LAKE ERIE AND ONTARIO...WITH GOOD MODEL AGREEMENT
THAT THE FRONT WILL MOVE ACROSS WESTERN NEW YORK THIS AFTERNOON.
RADAR SHOWS SHOWERS AND THUNDERSTORMS HAVE DEVELOPED OUT AHEAD OF
THIS FRONTAL BOUNDARY...WITH THE STEADIEST OF THIS TO MOVE INTO
WESTERN PORTIONS OF THE SOUTHERN TIER LATE THIS MORNING. WHILE
SOME OF THE 00Z/06 GUIDANCE STRUGGLED TO FORECAST EXACTLY WHERE
CONVECTION WOULD BREAK OUT...THE LATEST RUNS OF THE HRRR DEPICTS
CURRENT CONDITIONS FAIRLY WELL...AND THUS PROVIDES FAIRLY GOOD
GUIDANCE FOR THE NEXT FEW HOURS. FOLLOWING THIS...EXPECT SHOWERS
TO FILL IN TO THE NORTH LATE THIS MORNING...BRINGING AT LEAST SOME
PRECIPITATION TO NEARLY ALL OF THE REGION THROUGH EARLY AFTERNOON.
HEAVIEST SHOWERS WILL BE SOUTH...WHERE THERE STILL ARE QUITE A FEW
LIGHTNING STRIKES. NAM/GFS MODEL GUIDANCE SHOWS CONTINUED
ELEVATED INSTABILITY IN SOUTHERN SECTIONS...AND THIS IS CONSISTENT
WITH HRRR REFLECTIVITY FORECASTS. THE ONLY QUESTION IS HOW FAR
NORTH WILL THIS MAKE IT...WITH THE HRRR FORECASTING EXPANDING
SHOWER ACTIVITY THIS AFTERNOON ACROSS CENTRAL NEW YORK...LIKELY
DUE TO SOME LIMITED DAYTIME HEATING OUT AHEAD OF THE FRONT. FOR
NOW...KEEP THE MENTION OF THUNDER SOUTH OF I-90. QPFS WILL
VARY...WITH MOST AREAS LIKELY TO SEE A TENTH OF AN INCH OR TWO...WITH
LOCALLY HIGHER AMOUNTS TO A HALF INCH IN THUNDERSTORMS.
OTHERWISE...THE DAY WILL GET OFF TO A WARM AND BREEZY START.
TEMPERATURES WILL REMAIN IN THE 60S AHEAD OF THE RAIN
SHOWERS...WITH HIGHS IN THE UPPER 60S LIKELY IN THE FINGER LAKES
REGION WHERE RAIN WILL HOLD OFF A BIT LONGER.
MEANWHILE...SOUTHERLY WINDS WILL CONTINUE TO GUST TO 30 TO 35 MPH
IN MOST LOCATIONS...WITH GUSTS TO 40 MPH ACROSS HIGHER TERRAIN AND
IN THE BLACK RIVER VALLEY.
LATE THIS AFTERNOON THROUGH TONIGHT...THE FRONTAL BOUNDARY WILL GET
SUPPRESSED FURTHER SOUTH TO THE MASON/DIXON LINE AS HIGH PRESSURE
AND MUCH DRIER AIR BRIEFLY RIDGES SOUTHEAST FROM NORTHERN ONTARIO
PROVINCE. FOR OUR AREA...THIS WILL RESULT IN ANY LINGERING SHOWER
CHANCES ENDING FROM NORTHWEST TO SOUTHEAST LATE THIS AFTERNOON AND
EVENING FOLLOWED BY DRY WEATHER THE REMAINDER OF THE NIGHT...THOUGH
SOME CLOUDS WILL LINGER ACROSS AREAS SOUTH OF LAKE ONTARIO...WHICH
WILL BE CLOSER TO THE SLOWLY DEPARTING FRONTAL ZONE. AS FOR TEMPS...
COOLER AIR FILTERING IN BEHIND THE FRONT WILL RESULT IN TEMPS
FALLING BACK TO THE UPPER 30S TO LOWER 40S SOUTH OF LAKE ONTARIO...
AND TO THE LOWER-MID 30S ACROSS THE NORTH COUNTRY WHERE THERE WILL
BE LESS CLOUD COVER.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
A PROGRESSIVE HIGH AMPLITUDE FLOW WILL BE FOUND ACROSS THE UNITED
STATES DURING THIS PERIOD...WITH THE LOWER GREAT LAKES REGION BEING
FORTUNATE ENOUGH TO BE FOUND ON THE WARM SIDE OF AN EXPANSIVE RIDGE.
THIS WILL LEAD TO SEASONABLE CONDITIONS ON WEDNESDAY BEFORE
ANOMALOUS WARMTH RETURNS FOR THURSDAY AND FRIDAY. TEMPERATURES AT
THAT TIME COULD EASILY CLIMB TO MORE THAN 20 DEGREES F ABOVE NORMAL
VALUES. IT IS NOT OUT OF THE QUESTION THAT THE WARMER VALLEYS COULD
EVEN TICKLE THE 80 DEGREE MARK ON THURSDAY.
IN TERMS OF PCPN...THE BULK OF THIS PERIOD WILL BE RAIN-FREE. WHILE
THERE WILL BE THE CHANCE FOR SOME NUISANCE LIGHT SHOWERS AS THE
WARMER AIR WORKS INTO OUR REGION WEDNESDAY NIGHT AND THURSDAY...THE
HIGHEST CHANCE FOR ANY ADVERSE WEATHER WILL COME FRIDAY AFTERNOON
AND NIGHT WHEN A STRONG COLD FRONT WILL PLOW ACROSS THE LOWER GREAT
LAKES. THIS FEATURE COULD END UP GENERATING OUR FIRST WIDESPREAD
SEVERE WEATHER OUTBREAK. SOME DETAILS...
HIGH PRESSURE CENTERED OVER NORTHERN ONTARIO ON WEDNESDAY WILL ARCH
ACROSS THE LOWER GREAT LAKES AND NEW ENGLAND TO PROVIDE US WITH FAIR
SEASONABLE CONDITIONS. THE SUNNIEST CONDITIONS WILL BE FOUND ACROSS
THE EASTERN LAKE ONTARIO REGION WHILE SOME HIGH AND MID LEVEL CLOUDS
CAN BE EXPECTED OVER THE FAR WESTERN COUNTIES. GIVEN THE LIGHT
NORTHERLY FLOW...THE COOLEST WEATHER WILL LIKELY BE FOUND OVER THE
COUNTIES BORDERING THE SOUTH SHORE OF LK ONTARIO WHERE READINGS WILL
STRUGGLE INTO THE LOW 50S. ELSEWHERE...HIGHS SHOULD BE CLOSE TO
THEIR SEASONABLE NORMS OF 55 TO 60.
AS THE LARGE SFC HIGH MOVES EAST ACROSS QUEBEC WEDNESDAY NIGHT...A
DEEP INVERTED TROUGH WILL EXTEND FROM THE CENTRAL PLAINS NORTHEAST
ACROSS THE UPPER GREAT LAKES. A DEEP SOUTHERLY FLOW WILL DEVELOP
BETWEEN THESE SYSTEMS...WITH STRONG WARM ADVECTION FOUND OVER THE
GREAT LAKES REGION. THE LEADING EDGE OF THE WARMER AIRMASS (WARM
FRONT) MAY GENERATE SOME LIGHT SHOWERS/SPRINKLES ACROSS OUR FORECAST
AREA IN THE PROCESS...WITH MORE WIDESPREAD SHRA/TSRA REMAINING OVER
UPPER ONTARIO AND THE UPPER GREAT LAKES.
THE SOUTHERLY FLOW WILL INTENSIFY OVER THE LOWER GREAT LAKES AND
OHIO VALLEY ON THURSDAY AS THE AFOREMENTIONED WARM FRONT WILL LIFT
FROM THE THOUSAND ISLANDS REGION TO SOUTHERN QUEBEC. THIS WILL ALLOW
OUR SKIES TO PARTIALLY CLEAR DURING THE COURSE OF THURSDAY...MUCH
LIKE THEY DID YESTERDAY (MONDAY) WHEN TEMPERATURES REACHED INTO THE
70S. SPEAKING OF WHICH...H85 TEMPS WILL JUMP TO AROUND 14C BY
THURSDAY AFTERNOON AND THIS WILL EASILY SUPPORT DAYTIME HIGHS IN THE
MID 70S WITH 80 DEGREE READINGS NOT OUT OF THE QUESTION IN THE
WARMER VALLEYS.
WARM AND BREEZY CONDITIONS WILL THEN BE FOUND ACROSS THE FORECAST
AREA THURSDAY NIGHT AS DEEPENING LOW PRESSURE WILL LIFT TO LOWER
MICHIGAN WHILE SWEEPING A STRONG COLD FRONT AND ITS ASSOCIATED
SEVERE WEATHER ACROSS THE OHIO AND TENNESSEE VALLEYS. FOR OUR REGION
THOUGH...WE SHOULD BE MAINLY DRY AND QUITE MILD WITH TEMPERATURES
HAVING TROUBLE FALLING BELOW 60. IT WILL BE A LITTLE ON THE HUMID
SIDE AS WELL...MAKING IT FEEL MORE LIKE A NIGHT IN MID-LATE JUNE.
FRIDAY WILL FEATURE VERY UNSETTLED WEATHER AS THE DEEP SFC LOW
TO OUR WEST WILL PUSH ITS STRONG COLD FRONT ACROSS MUCH OF OUR
REGION. FROM THIS VANTAGE POINT...GUIDANCE HAS BEEN CONSISTENT WITH
BRINGING THE FRONT ACROSS WESTERN NEW YORK DURING THE AFTERNOON AND
EVENING. IF THIS TIMING HOLDS UP...TEMPERATURES SHOULD BE ABLE TO
JUMP BACK INTO THE 70S BEFORE THE THICKER CLOUD COVER AND FRONTAL
PCPN MOVES IN. SPEAKING OF WHICH...GIVEN THE STRONG DYNAMICS OF THE
SYNOPTIC SYSTEM AND THE PRESENCE OF A 60-70KT LOW LEVEL JET...WOULD
ANTICIPATE AT LEAST THE THREAT FOR STRONG TO SEVERE THUNDERSTORMS
AHEAD/DURING THE FRONTAL PASSAGE. WHILE GUIDANCE IS NOT DEPICTING
SIGNIFICANT INSTABILITY...CONVECTION COULD EASILY BE SUPPORTED BY
THE STRENGTH OF THE UNDERLYING SYNOPTICS. THE WIND PROFILE AHEAD OF
THE FRONT DEPICTS ALOT OF SHEAR AS WELL...SO THIS IS A VALID
CONCERN. WILL MENTION THIS THREAT IN THE HAZARDOUS WEATHER OUTLOOK.
AS IF THE POTENTIAL FOR STRONG TO SEVERE THUNDERSTORMS IS NOT
ENOUGH...THE STRONG LOW LEVEL JET AND FAVORABLE TRACK OF THE DEEP
SFC LOW FROM LOWER MICHIGAN AND LAKE HURON TO SOUTHERN QUEBEC WILL
SET THE STAGE FOR A SYNOPTIC WIND EVENT. ADVISORY CRITERIA SOUTHERLY
WINDS WILL BE POSSIBLE AHEAD OF THE FRONT ACROSS THE HIGHER
TERRAIN...THEN IN THE WAKE OF THE FRONT...THERE WILL BE AN 8 HOUR
PERIOD WHERE SOUTHWEST WINDS WITHIN THE COLD ADVECTION COULD PRODUCE
SFC WIND GUSTS IN EXCESS OF 50 MPH DOWNWIND OF LK ERIE LATE FRIDAY
AFTERNOON AND THE FIRST HALF OF FRIDAY NIGHT. STAY TUNED.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
NOTABLY COOLER WEATHER WILL CHARACTERIZE THIS PERIOD AS SEASONABLY
COOL AIR WILL ACCOMPANY EXPANSIVE HIGH PRESSURE FROM THE NORTHERN
PLAINS.
ON SATURDAY...HIGH PRESSURE WILL GRADUALLY BUILD ACROSS THE UPPER
GREAT LAKES WHILE A DEEP STORM SYSTEM WILL DRIFT TO COASTAL QUEBEC.
THIS WILL KEEP A RELATIVELY TIGHT PRESSURE GRADIENT ACROSS OUR
REGION SO THE STRONG WINDS FROM FRIDAY NIGHT WILL ONLY SLOWLY
SUBSIDE DURING THE COURSE OF SATURDAY. THE GUSTY WINDS AND MUCH
COOLER AIRMASS WILL MAKE FOR A CHILLY DAY AS TEMPS WILL STRUGGLE TO
CLIMB INTO THE MID TO UPPER 40S. THERE COULD ALSO BE A COUPLE
LEFTOVER SHOWERS THROUGH MIDDAY...MAINLY FOR SITES EAST OF
ROCHESTER.
THE EXPANSIVE SFC HIGH WILL BUILD ACROSS OUR REGION SATURDAY NIGHT
AND SUNDAY. THIS WILL PROVIDE US WITH MAINLY CLEAR SKIES FOR THE
SECOND HALF OF THE WEEKEND...ALTHOUGH TEMPERATURES WILL STILL BE
SOME 5 TO 10 DEG F BELOW NORMAL. THE CHILL WILL BE TEMPERED ON
SUNDAY THOUGH WITH AMPLE SUNSHINE.
FOR MONDAY...THE CENTER OF THE SFC HIGH WILL MOVE TO THE CANADIAN
MARITIMES. THE RETURN FLOW AROUND THE HIGH WILL PROMOTE SOME WEAK
WARM ADVECTION OVER THE LOWER GREAT LAKES SO THAT TEMPERATURES WILL
CLIMB BACK TO NEAR NORMAL LEVELS FOR MONDAY.
&&
.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
THROUGH 12Z...DRY VFR WEATHER WILL CONTINUE ACROSS THE AREA...ALONG
WITH AN INCREASE IN MID-LEVEL CLOUD COVER IN ADVANCE OF A COLD FRONT
APPROACHING FROM THE CENTRAL GREAT LAKES. LOW LEVEL WIND SHEAR
CONCERNS WILL ALSO PERSIST COURTESY OF A 50 KT SOUTHWESTERLY JET AT
1500 FEET...BEFORE INCREASING MIXING HELPS ALLEVIATE THE LLWS
BETWEEN 12Z AND 14Z THIS MORNING.
AFTER THAT TIME...A COLD FRONT WILL CROSS THE REGION...BRINGING A
PERIOD OF SHOWERS THAT WILL FOCUS ON THE 14Z-19Z TIME FRAME ACROSS
THE FAR WEST...AND 16Z-22Z FURTHER EAST. THESE WILL PROBABLY BRING A
PERIOD OF MVFR CONDITIONS THAT WILL PROBABLY LINGER FOR A FEW HOURS
FOLLOWING THE FROPA...BEFORE DRIER AIR WORKING IN THE CENTRAL GREAT
LAKES BRINGS A RETURN TO VFR CONDITIONS LATER THIS AFTERNOON AND
EARLY THIS EVENING. ONCE ESTABLISHED...THESE VFR CONDITIONS SHOULD
THEN PERSIST THROUGH THE BALANCE OF THE PERIOD.
OUTLOOK...
WEDNESDAY...MAINLY VFR.
WEDNESDAY NIGHT AND THURSDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
FRIDAY...DETERIORATION TO MVFR WITH SHOWERS BECOMING LIKELY ALONG
WITH A CHANCE OF THUNDERSTORMS...SOME OF WHICH COULD PRODUCE GUSTY
WINDS.
SATURDAY...VFR/MVFR WITH A CHANCE OF SHOWERS.
&&
.MARINE...
IN ADVANCE OF A COLD FRONT...SOUTHERLY WINDS TO 15 TO 25 KNOTS
WILL AFFECT EASTERN PORTIONS OF LAKE ERIE AND ONTARIO THIS
MORNING...FOR WHICH SMALL CRAFT ADVISORIES WILL BE IN PLACE.
FOLLOWING THE FRONTAL PASSAGE...WINDS WILL VEER TO WESTERLY AND
DIMINISH THIS AFTERNOON... THEN WILL BECOME RELATIVELY LIGHT FOR
TONIGHT AND WEDNESDAY AS HIGH PRESSURE BRIEFLY NOSES SOUTHEASTWARD
ACROSS THE REGION.
IT SHOULD ALSO BE NOTED THAT WHILE THE FRONT WILL MAINLY JUST
PRODUCE SOME SHOWERS TODAY...A THUNDERSTORM OR TWO WILL ALSO BE
POSSIBLE ACROSS LAKE ERIE.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR LEZ040-
041.
SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON
FOR LOZ044-045.
&&
$$
SYNOPSIS...JJR
NEAR TERM...JJR
SHORT TERM...RSH
LONG TERM...RSH
AVIATION...APFFEL/JJR
MARINE...APFFEL/JJR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
849 AM EDT TUE APR 16 2013
.SYNOPSIS...
A WEAK COLD FRONT WILL MOVE SOUTH ACROSS THE AREA TODAY AND STALL
ACROSS SOUTHERN OHIO TONIGHT. THIS FRONT WILL LIFT NORTH AS A WARM
FRONT ON WEDNESDAY NIGHT AHEAD OF A LOW PRESSURE SYSTEM APPROACHING
FROM THE PLAINS. THIS SYSTEM WILL TRACK NORTHEAST THROUGH THE GREAT
LAKES REGION PULLING A STRONG COLD FRONT EAST ACROSS THE AREA ON
FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
UPDATED...MINOR ADJUSTMENT TO POP AND WX GRIDS BASED ON RADAR THIS
MORNING AND EXPECTED MOVEMENT THROUGH THE MORNING AND EARLY
AFTERNOON. ALSO ADJUSTED HOURLY TEMPS AND AFTERNOON HIGH TEMP
USING HRRR GUIDANCE WHICH SHOWS NICELY THE COOL DOWN OFF THE LAKE
THIS AFTERNOON AS WINDS TURN ONSHORE.
ORIGINAL DISCUSSION...APPROACHING FRONTAL BOUNDARY IS STILL
LOCATED ACROSS SE LOWER MICHIGAN EARLY THIS MORNING. CONVECTION
HAS BEEN RAPIDLY APPROACHING ACROSS CENTRAL ILLINOIS AND WESTERN
INDIANA WHERE DEEP MOISTURE CONVERGENCE IS MAXIMIZED ALONG THE
925-850MB FRONT. WE WILL CONTINUE TO SEE MOISTURE ADVECTION
INCREASING ACROSS NRN OHIO WHERE THE LOW LEVEL JET IS FOCUSED WITH
CONVERGENCE INCREASING AS THE FRONT SETTLES SOUTH. EXPECTING TO
SEE SHOWERS AND THUNDERSTORMS SPREAD EAST ACROSS NRN OHIO...EVEN
REACHING NW PA BY LATE THIS MORNING. OVERALL COVERAGE OF SHOWERS
WILL DECREASE BY THIS AFTERNOON AS WE LOSE THE LOW LEVEL JET
SUPPORT AND MORE STABLE AIR ARRIVES BEHIND THE FRONT. TEMPERATURES
WILL FALL AS THE RAIN MOVES IN THIS MORNING AND WILL STRUGGLE TO
RECOVER BEHIND THE FRONT THIS AFTERNOON. HIGHS WILL RANGE FROM THE
UPPER 50S TO LOW 60S SOUTH.
CHALLENGE FOR THIS AFTERNOON WILL BE DETERMINING COVERAGE OF SHOWERS
AND THUNDERSTORMS AS THE FRONT SINKS SOUTH WHILE MAIN UPPER LEVEL
SUPPORT PASSES WELL NORTH OF THE AREA. MODEL SOUNDING ARE A BIT
OVERDONE WITH DEWPOINTS BY THIS AFTERNOON AND THINK WE WILL SEE
VALUES ACROSS CENTRAL OHIO PEAK IN THE LOWER 50S WHICH WILL LIMIT
SURFACE BASED INSTABILITY. WE WILL HAVE TO KEEP AN EYE ON WHERE THE
FRONTAL BOUNDARY SETS UP BUT EXPECTING BEST CHANCES WILL BE ACROSS
THE EXTREME SE PORTION OF THE FORECAST AREA FROM MOUNT VERNON TO
YOUNGSTOWN ALONG AND BEHIND THE FRONT. A LITTLE HARD TO PINPOINT IF
THERE WILL BE ENOUGH SHORTWAVE ENERGY RIDING AROUND THE RIDGE LATE
THIS AFTERNOON TO FIRE OFF A SECOND ROUND OF CONVECTION BUT WILL
HOLD ONTO CHANCE POPS TO ACCOUNT FOR THIS. SPC KEEP THE SLIGHT RISK
FOR SEVERE THUNDERSTORMS JUST TO OUR SOUTH AND AGREE WITH THE
LOCATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
UPPER LEVEL RIDGE BUILDS AGAIN OVERNIGHT AS THE WESTERN TROUGH
PUSHES EASTWARD. THE NAM HAS BEEN THE MORE ENERGETIC MODEL WITH
ISENTROPIC ASCENT INCREASING ACROSS NW OHIO AND TRIES TO SHOW
SHOWERS DEVELOPING. THINK THIS IS OVERDONE WITH BETTER LIFT
ASSOCIATED WITH THE LLJ FOCUSED BACK TOWARDS IOWA SO WILL ONLY
CARRY LOW POPS IN THE WEST OVERNIGHT. THE WARM FRONT LOOKS SLOW TO
LIFT BACK NORTH ON WEDNESDAY WITH MOSTLY CLOUDY SKIES IN PLACE
ACROSS THE AREA. EAST TO NORTHEAST FLOW OFF THE LAKE WILL KEEP
TEMPERATURES AT OR BELOW NORMAL IN THE UPPER 50S TO NEAR 60
DEGREES.
WARM FRONT PUSHES BACK NORTH WEDNESDAY NIGHT LEAVING THE FORECAST
AREA IN THE WARM SECTOR ON THURSDAY. BREEZY SOUTHERLY WINDS NEAR 20
MPH WITH GUSTS OF 30-35 MPH ARE POSSIBLE WHICH WILL HELP TO PUSH
TEMPERATURES NEAR THE 80 DEGREE MARK. THE FRONT WILL BE CLOSE ENOUGH
TO NW OHIO TO SEE OCCASIONAL SHOWERS/THUNDERSTORMS AND ENOUGH CLOUDS
TO KEEP TEMPERATURES A FEW DEGREES COOLER. OTHERWISE THE FRONT
FINALLY SWEEPS EAST ACROSS THE AREA ON FRIDAY BRINGING A RETURN
TO MUCH COOLER TEMPERATURES FOR THE WEEKEND. MODELS HAVE BEEN
SLOWING DOWN THE TIMING OF THE FRONT BUT CURRENTLY SHOW IT
CLEARING MOST OF THE AREA BY MID AFTERNOON ON FRIDAY. ANY FURTHER
SLOWING WILL HELP TO INCREASE INSTABILITY AND POTENTIAL FOR STRONGER
THUNDERSTORMS ALONG THE FRONT.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
THE UPPER LEVEL TROUGH SHOULD MOVE EAST OF THE REGION ON SATURDAY.
HOWEVER THERE MAY STILL BE SOME LINGERING RAIN OR SNOW SHOWERS
ACROSS NW PA THROUGH SATURDAY MORNING. HIGH PRESSURE IS EXPECTED TO
TAKE CONTROL BY SATURDAY NIGHT BUT WILL MOVE OFF THE NEW ENGLAND
COAST BY MONDAY MORNING. AFTER A COLD DAY WITH HIGHS IN THE 40S ON
SATURDAY IT WILL BE WARMER ON SUNDAY...BUT STILL BELOW SEASONAL
AVERAGES. AS SOUTHERLY WINDS RETURN ON MONDAY HIGHS WILL RETURN TO
WITHIN A COUPLE DEGREES OF 60.
&&
.AVIATION /13Z TUESDAY THROUGH SATURDAY/...
OUTFLOW FROM SHOWERS AND THUNDERSTORMS ACROSS NW OHIO ARE HELPING
MOVE A COLD FRONT INTO THE CENTRAL PORTION OF NORTHERN OHIO. THERE
HAS BEEN SOME MVFR CONDITIONS WITH LOCALIZED IFR IN THE HEAVIEST
THUNDERSTORMS. THE BETTER CHANCES OF SEEING THUNDER THIS MORNING
WILL BE GENERALLY ALONG AND NORTH OF A KFDY TO KCLE TO KERI LINE.
MOST OF THE MORNING THUNDERSTORMS SHOULD WEAKEN AS THEY LIFT TO
THE NORTHEAST. AWAY FROM THESE MORNING SHOWERS AND THUNDERSTORMS
MOST LOCATIONS WILL BE VFR.
UNCERTAINTY FOR THE AFTERNOON IS HOW MUCH SHOWER AND THUNDERSTORM
ACTIVITY WILL DEVELOP ALONG THE FRONTAL BOUNDARY THAT SHOULD BE
NEAR A KJHW TO KI43 LINE AROUND 20Z. BELIEVE THE THUNDER CHANCES
ARE HIGH ENOUGH TO MENTION AT KCAK AND KYNG FOR THE MID TO LATE
AFTERNOON. THE SHOWERS AND THUNDERSTORMS THAT CAN DEVELOP WILL
PRODUCE MVFR CONDITIONS. AWAY FROM THE SHOWERS CEILINGS SHOULD BE
VFR.
WINDS WILL REMAIN GUSTY AHEAD OF THE FRONT FROM A SOUTHERLY
DIRECTION BUT WILL SHIFT AROUND TO THE WEST AND NORTHWEST THROUGH
THE AFTERNOON. WINDS WILL EVENTUALLY MAKE IT AROUND TO THE
NORTHEAST DURING THE EVENING.
.OUTLOOK...NON VFR AT TIMES IN SHOWERS AND THUNDERSTORMS TUESDAY NIGHT
INTO WEDNESDAY AND AGAIN ON FRIDAY.
&&
.MARINE...
SOUTHERLY WINDS WILL BE STRONGEST THIS MORNING ALONG THE PA
SHORELINE. BELIEVE WE WILL REMAIN JUST UNDER SMALL CRAFT CONDITIONS.
WINDS WILL SHIFT LATE THIS MORNING TO EARLY AFTERNOON AS A COLD
FRONT MOVES ACROSS THE LAKE. THIS FRONT WILL STALL NEAR THE OHIO
RIVER VALLEY THEN MOVE BACK TO THE NORTH AS A WARM FRONT. THE WARM
FRONT WILL LIFT NORTH OF LAKE ERIE WEDNESDAY WITH SOUTHERLY WINDS
RETURNING. SOUTHERLY WINDS MAY END UP BEING STRONG ENOUGH AHEAD OF
ANOTHER COLD FRONT ON FRIDAY TO CAUSE SMALL CRAFT ADVISORY
CONDITIONS. COLD ADVECTION IN THE WAKE OF THIS FRONT WILL BE STRONG
ENOUGH TO INCREASE SOUTHWESTERLY WINDS TO 30 KNOTS. WE WILL NEED TO
MONITOR FOR THE POTENTIAL OF GALE CONDITIONS FOR A FEW HOURS FRIDAY
NIGHT INTO EARLY SATURDAY. HIGH PRESSURE WILL TAKE CONTROL BY
SATURDAY NIGHT WITH CALMER CONDITIONS EXPECTED.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC/TK
SHORT TERM...KEC
LONG TERM...MULLEN
AVIATION...MULLEN
MARINE...MULLEN
FOR FREQUENTLY ASKED QUESTIONS ABOUT THE AREA FORECAST DISCUSSION
VISIT...
HTTP://WEATHER.GOV/SALTLAKECITY/GENERAL/AFD_FAQS.PHP (ALL LOWER CASE)
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
629 AM CDT TUE APR 16 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CDT TUE APR 16 2013
WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWS A BROAD/RELATIVELY
DEEP UPPER TROUGH AXIS SITUATED OVER THE WEST COAST/INTERMOUNTAIN
REGION. SOUTHWEST FLOW ALOFT OUT F THIS TROUGH WAS SPILLING QUITE A
BIT OF MID/HIGH CLOUD INTO THE REGION. AT THE SURFACE...THE FORECAST
AREA WAS STILL UNDER THE INFLUENCE OF THE LOW PRESSURE THAT BROUGHT
A WINTRY MIX/RAINFALL INTO THE AREA OVER THE WEEKEND. CYCLONIC FLOW
AROUND THE LOW OVER SOUTHERN ONTARIO WAS PRODUCING AN EXTENSIVE
STRATOCUMULUS FILED ACROSS NORTHERN MN INTO NORTHER WI.
OTHERWISE...TEMPERATURES AT 3 AM WERE IN THE 30S.
MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE CLOUDS AND
TEMPERATURES THROUGH TONIGHT.
16.00Z NCEP MODEL SUITE AS WELL AS THE ECMWF AND GEM ALL IN GOOD
AGREEMENT IN THE SHORT TERM.
FOR TODAY...WILL SEE THE LOW OVER ONTARIO LIFT FARTHER EAST INTO
QUEBEC...WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN PLAINS.
THIS WILL KEEP US DRY...BUT SOUTHWEST FLOW ALOFT WILL CONTINUE TO
SPILL MID/HIGH CLOUD INTO THE REGION. NOT TOO CONFIDENT HOW THICK
THIS CLOUD COVER WILL BE. BUFKIT SHOWS ALTERNATE THICKENING/THINNING
THROUGH THE DAY. FEEL WE SEE SOMEWHERE BETWEEN 40-60 PERCENT
OPAQUENESS FOR PARTLY TO MOSTLY SUNNY CONDITIONS. TEMPERATURES TODAY
EXPECTED TO TOP OFF IN THE MIDDLE 40S ACROSS NORTH CENTRAL WI...TO
THE LOWER 50S ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHWEST WI.
CLOUDS WILL THEN THICKEN TONIGHT AHEAD OF FAIRLY STRONG CYCLOGENESIS
EAST OF THE COLORADO ROCKY MOUNTAIN FRONT WITH INCREASING MOISTURE
TRANSPORT AND ISENTROPIC LIFT. MOISTURE WILL BE BATTLING DRY AIR
INITIALLY...BUT FEEL SOME RAIN WILL BE POSSIBLE ACROSS NORTHEAST
IA/SOUTHEAST MN/FAR SOUTHWEST WI TOWARD MORNING. OTHERWISE...WITH
THICKENING CLOUDS...LOOK FOR TEMPERATURES TO RANGE FROM NEAR 30
ACROSS NORTH CENTRAL WI...TO THE MIDDLE AND UPPER 30S ACROSS
NORTHEAST IA INTO SOUTHWEST WI.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 354 AM CDT TUE APR 16 2013
LOOK FOR RAIN TO OVERSPREAD THE AREA ON WEDNESDAY AS STRONG LOW
PRESSURE MOVING OUT INTO THE PLAINS INCREASES MOISTURE TRANSPORT
INTO THE AREA. NAM ALSO INDICATING SOME ELEVATED MUCAPE OF A COUPLE
HUNDRED J/KG GOING INTO THE AFTER NOON FOR PERHAPS A CLAP OR TWO OF
THUNDER.
RAINFALL EXPECTED TO REALLY PICK UP OVER THE AREA WEDNESDAY
AFTERNOON/NIGHT AS THE LOW MOVES FROM MO INTO SOUTHEAST WI. SREF
INDICATING INCREASING 850-700MB FRONTOGENESIS OVER THE FORECAST AREA
NORTHWEST OF THE LOW ALONG WITH INCREASING MOISTURE TRANSPORT...
WITH PRECIPITABLE WATERS MOVING INTO THE 1-1.5 INCH RANGE. RAIN
RATES COULD GET MODERATE TO HEAVY AT TIMES GIVEN THIS SCENARIO. RAIN
THEN EXPECTED TO TAPER OFF ON THURSDAY AS THE LOW PULLS INTO LOWER
MI. THINKING THAT FOCUSED FORCING ALONG WITH MUCH HIGHER THAN NORMAL
PRECIPITABLE WATER VALUES WILL YIELD RAINFALL AMOUNTS SOMEWHERE IN
THE 1.5-3.5 INCH RANGE WITH A FEW LOCALLY HIGHER AMOUNTS GIVEN THE
EMBEDDED THUNDERSTORM POTENTIAL. HYDROLOGY EXPECTED TO BECOME AN
ISSUE ONCE AGAIN WITH RIVERS RUNNING FAIRLY HIGH RIGHT NOW. MORE ON
THIS IS COVERED IN THE HYDROLOGY SECTION BELOW. CONCERN IS
INCREASING THAT A FLOOD WATCH MAY BECOME NECESSARY AS WELL WITH
SATURATED GROUND AND POTENTIAL FOR OVERLAND FLOODING IN ADDITION TO
RIVER FLOODING SINCE OUR 6-HRLY FLASH FLOOD GUIDANCE IS ONLY RUNNING
2-3 INCHES. WILL HAVE THE DAY SHIFT ASSESS THIS WITH THE 12Z MODEL
RUNS.
ATTENTION THEN TURNS TO SIGNIFICANT SNOWFALL POTENTIAL FOR THURSDAY
NIGHT INTO FRIDAY. MODELS ARE BECOMING MORE IN AGREEMENT AND
CONSISTENT WITH INCREASING SNOW SIGNAL FOR THE AREA. ECMWF/GFS/GEM
ALL BRING ANOTHER WAVE OF LOW PRESSURE UP ALONG THE EXISTING
BAROCLINIC ZONE AS A VIGOROUS MID-LEVEL TROUGH/CLOSED LOW MOVES
TOWARD THE AREA FROM THE PLAINS. STRONG DEFORMATION ZONE THEN SETS
UP ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. LATEST GFS COB
WANTS TO PRODUCE 8+ INCHES/LOCALLY HIGHER AMOUNTS NORTHWEST OF A
LINE ROUGHLY RUNNING FROM MEDFORD AND LA CROSSE WI...TO NEAR OELWEIN
IA. HEADLINES WILL LIKELY BE NEEDED. WILL PASS THIS ONTO THE
DAYSHIFT AS WELL FOR FURTHER ASSESSMENT.
FRIDAY NIGHT THROUGH SATURDAY LOOKS DRY WITH HIGH PRESSURE MOVING
IN.
PRECIPITATION CHANCES WILL RETURN SATURDAY NIGHT THROUGH MONDAY AS
LOW PRESSURE MOVES ACROSS THE NORTHERN PLAINS INTO THE UPPER
MISSISSIPPI RIVER VALLEY REGION.
OTHERWISE...LOOK FOR BELOW NORMAL TEMPERATURES TO CONTINUE THROUGH
THE WEEKEND...POSSIBLY GETTING TO NEAR NORMAL BY MONDAY.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 629 AM CDT TUE APR 16 2013
AN AREA OF STRATUS GENERALLY NORTH OF INTERSTATE 90 WAS SLOWLY
SAGGING SOUTHWARD. RAP AND NAM BUFKIT SOUNDINGS INDICATE THESE
SHOULD MIX OUT BY MID TO LATE MORNING WITH VFR CONDITIONS AFTER
THAT. MOISTURE TRANSPORT WILL INCREASE LATE TONIGHT AHEAD OF A
DEVELOPING STORMS SYSTEM OVER THE PLAINS. THIS WILL SPREAD A MID
DECK OF CLOUDS INTO THE TAF SITES...BUT ANY PRECIPITATION SHOULD
HOLD OFF UNTIL AFTER 12Z.
&&
.HYDROLOGY...MAINLY WEDNESDAY AND WEDNESDAY NIGHT
ISSUED AT 354 AM CDT TUE APR 16 2013
ADDITIONAL RAINFALL WED/WED NIGHT/THU POSES A FLOODING THREAT FOR
MOST IF NOT ALL RIVERS AND STREAMS IN OUR FORECAST AREA. RUNOFF FROM
EXPECTED 1.5 TO 3.5 INCHES OF RAINFALL FROM WED THROUGH THU WILL
LIKELY PRODUCE ADDITIONAL RISES ON THE TRIBUTARY RIVERS/ STREAMS
THAT ARE ALREADY RUNNING HIGH FROM RECENT RAINFALL AND SNOW MELT
THIS PAST WEEK. GIVEN THIS EXPECTED RAINFALL ALONG WITH LOCALIZED
HIGHER RAINFALL RATES...ADDITIONAL FLOODING IS POSSIBLE IF NOT
LIKELY ON THE TRIBUTARY RIVERS LATER IN THE WEEK INTO THE WEEKEND.
WILL CONTINUE HYDROLOGIC OUTLOOK PRODUCT ADDRESSING THE
RAIN/FLOODING THREATS LATER IN THE WEEK.
LOOK FOR WATER LEVELS ON THE MISSISSIPPI RIVER TO REMAIN NEARLY
STEADY OR GRADUALLY RISE THIS WEEK AS RUNOFF FROM RECENT RAINS AND
SNOWMELT MOVES DOWNSTREAM. THE ADDITIONAL RAINS ON WEDNESDAY THROUGH
THURSDAY WOULD CREATE ADDITIONAL RISES ON THE MISSISSIPPI
RIVER...BUT MOST OF THESE RISES FROM THE WED-THU RAINS EXPECTED NOT
TO SHOW UP IN THE MISSISSIPPI RIVER UNTIL EARLY NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...RABERDING
HYDROLOGY....DAS/RRS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
354 AM CDT TUE APR 16 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CDT TUE APR 16 2013
WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWS A BROAD/RELATIVELY
DEEP UPPER TROUGH AXIS SITUATED OVER THE WEST COAST/INTERMOUNTAIN
REGION. SOUTHWEST FLOW ALOFT OUT F THIS TROUGH WAS SPILLING QUITE A
BIT OF MID/HIGH CLOUD INTO THE REGION. AT THE SURFACE...THE FORECAST
AREA WAS STILL UNDER THE INFLUENCE OF THE LOW PRESSURE THAT BROUGHT
A WINTRY MIX/RAINFALL INTO THE AREA OVER THE WEEKEND. CYCLONIC FLOW
AROUND THE LOW OVER SOUTHERN ONTARIO WAS PRODUCING AN EXTENSIVE
STRATOCUMULUS FILED ACROSS NORTHERN MN INTO NORTHER WI.
OTHERWISE...TEMPERATURES AT 3 AM WERE IN THE 30S.
MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE CLOUDS AND
TEMPERATURES THROUGH TONIGHT.
16.00Z NCEP MODEL SUITE AS WELL AS THE ECMWF AND GEM ALL IN GOOD
AGREEMENT IN THE SHORT TERM.
FOR TODAY...WILL SEE THE LOW OVER ONTARIO LIFT FARTHER EAST INTO
QUEBEC...WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN PLAINS.
THIS WILL KEEP US DRY...BUT SOUTHWEST FLOW ALOFT WILL CONTINUE TO
SPILL MID/HIGH CLOUD INTO THE REGION. NOT TOO CONFIDENT HOW THICK
THIS CLOUD COVER WILL BE. BUFKIT SHOWS ALTERNATE THICKENING/THINNING
THROUGH THE DAY. FEEL WE SEE SOMEWHERE BETWEEN 40-60 PERCENT
OPAQUENESS FOR PARTLY TO MOSTLY SUNNY CONDITIONS. TEMPERATURES TODAY
EXPECTED TO TOP OFF IN THE MIDDLE 40S ACROSS NORTH CENTRAL WI...TO
THE LOWER 50S ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHWEST WI.
CLOUDS WILL THEN THICKEN TONIGHT AHEAD OF FAIRLY STRONG CYCLOGENESIS
EAST OF THE COLORADO ROCKY MOUNTAIN FRONT WITH INCREASING MOISTURE
TRANSPORT AND ISENTROPIC LIFT. MOISTURE WILL BE BATTLING DRY AIR
INITIALLY...BUT FEEL SOME RAIN WILL BE POSSIBLE ACROSS NORTHEAST
IA/SOUTHEAST MN/FAR SOUTHWEST WI TOWARD MORNING. OTHERWISE...WITH
THICKENING CLOUDS...LOOK FOR TEMPERATURES TO RANGE FROM NEAR 30
ACROSS NORTH CENTRAL WI...TO THE MIDDLE AND UPPER 30S ACROSS
NORTHEAST IA INTO SOUTHWEST WI.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 354 AM CDT TUE APR 16 2013
LOOK FOR RAIN TO OVERSPREAD THE AREA ON WEDNESDAY AS STRONG LOW
PRESSURE MOVING OUT INTO THE PLAINS INCREASES MOISTURE TRANSPORT
INTO THE AREA. NAM ALSO INDICATING SOME ELEVATED MUCAPE OF A COUPLE
HUNDRED J/KG GOING INTO THE AFTER NOON FOR PERHAPS A CLAP OR TWO OF
THUNDER.
RAINFALL EXPECTED TO REALLY PICK UP OVER THE AREA WEDNESDAY
AFTERNOON/NIGHT AS THE LOW MOVES FROM MO INTO SOUTHEAST WI. SREF
INDICATING INCREASING 850-700MB FRONTOGENESIS OVER THE FORECAST AREA
NORTHWEST OF THE LOW ALONG WITH INCREASING MOISTURE TRANSPORT...
WITH PRECIPITABLE WATERS MOVING INTO THE 1-1.5 INCH RANGE. RAIN
RATES COULD GET MODERATE TO HEAVY AT TIMES GIVEN THIS SCENARIO. RAIN
THEN EXPECTED TO TAPER OFF ON THURSDAY AS THE LOW PULLS INTO LOWER
MI. THINKING THAT FOCUSED FORCING ALONG WITH MUCH HIGHER THAN NORMAL
PRECIPITABLE WATER VALUES WILL YIELD RAINFALL AMOUNTS SOMEWHERE IN
THE 1.5-3.5 INCH RANGE WITH A FEW LOCALLY HIGHER AMOUNTS GIVEN THE
EMBEDDED THUNDERSTORM POTENTIAL. HYDROLOGY EXPECTED TO BECOME AN
ISSUE ONCE AGAIN WITH RIVERS RUNNING FAIRLY HIGH RIGHT NOW. MORE ON
THIS IS COVERED IN THE HYDROLOGY SECTION BELOW. CONCERN IS
INCREASING THAT A FLOOD WATCH MAY BECOME NECESSARY AS WELL WITH
SATURATED GROUND AND POTENTIAL FOR OVERLAND FLOODING IN ADDITION TO
RIVER FLOODING SINCE OUR 6-HRLY FLASH FLOOD GUIDANCE IS ONLY RUNNING
2-3 INCHES. WILL HAVE THE DAY SHIFT ASSESS THIS WITH THE 12Z MODEL
RUNS.
ATTENTION THEN TURNS TO SIGNIFICANT SNOWFALL POTENTIAL FOR THURSDAY
NIGHT INTO FRIDAY. MODELS ARE BECOMING MORE IN AGREEMENT AND
CONSISTENT WITH INCREASING SNOW SIGNAL FOR THE AREA. ECMWF/GFS/GEM
ALL BRING ANOTHER WAVE OF LOW PRESSURE UP ALONG THE EXISTING
BAROCLINIC ZONE AS A VIGOROUS MID-LEVEL TROUGH/CLOSED LOW MOVES
TOWARD THE AREA FROM THE PLAINS. STRONG DEFORMATION ZONE THEN SETS
UP ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. LATEST GFS COB
WANTS TO PRODUCE 8+ INCHES/LOCALLY HIGHER AMOUNTS NORTHWEST OF A
LINE ROUGHLY RUNNING FROM MEDFORD AND LA CROSSE WI...TO NEAR OELWEIN
IA. HEADLINES WILL LIKELY BE NEEDED. WILL PASS THIS ONTO THE
DAYSHIFT AS WELL FOR FURTHER ASSESSMENT.
FRIDAY NIGHT THROUGH SATURDAY LOOKS DRY WITH HIGH PRESSURE MOVING
IN.
PRECIPITATION CHANCES WILL RETURN SATURDAY NIGHT THROUGH MONDAY AS
LOW PRESSURE MOVES ACROSS THE NORTHERN PLAINS INTO THE UPPER
MISSISSIPPI RIVER VALLEY REGION.
OTHERWISE...LOOK FOR BELOW NORMAL TEMPERATURES TO CONTINUE THROUGH
THE WEEKEND...POSSIBLY GETTING TO NEAR NORMAL BY MONDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1145 PM CDT MON APR 15 2013
THE AREA OF LOW PRESSURE AT THE SURFACE HAS MOVED NORTHEAST INTO
ONTARIO THIS EVENING. THIS HAS ALLOWED THE CYCLONIC FLOW TO RELAX
ENOUGH FOR THE WINDS TO DROP DOWN TO ABOUT 10 KNOTS. THE WINDS ARE
EXPECTED TO REMAIN AT THIS SPEED THROUGH MUCH OF TUESDAY BEFORE
TURNING MORE TO THE NORTHEAST AS WEAK HIGH PRESSURE MOVES BY TO
THE NORTH. ENOUGH DRY AIR HAS BEEN PULLED IN TO ALLOW THE LOW AND
MID LEVEL CLOUDS TO DISSIPATE LEAVING JUST SOME OCCASIONAL HIGH
CLOUDS TO COME IN FROM THE SOUTHWEST. WILL SEE VFR CONDITIONS
THROUGH THE PERIOD...BUT MOISTURE FROM THE NEXT SYSTEM WILL BRING
IN A CEILING AROUND 10K FEET LATE TUESDAY AFTERNOON OR EVENING
WITH THIS GRADUALLY LOWERING THROUGH THE EVENING.
&&
.HYDROLOGY...MAINLY WEDNESDAY AND WEDNESDAY NIGHT
ISSUED AT 354 AM CDT TUE APR 16 2013
ADDITIONAL RAINFALL WED/WED NIGHT/THU POSES A FLOODING THREAT FOR
MOST IF NOT ALL RIVERS AND STREAMS IN OUR FORECAST AREA. RUNOFF FROM
EXPECTED 1.5 TO 3.5 INCHES OF RAINFALL FROM WED THROUGH THU WILL
LIKELY PRODUCE ADDITIONAL RISES ON THE TRIBUTARY RIVERS/ STREAMS
THAT ARE ALREADY RUNNING HIGH FROM RECENT RAINFALL AND SNOW MELT
THIS PAST WEEK. GIVEN THIS EXPECTED RAINFALL ALONG WITH LOCALIZED
HIGHER RAINFALL RATES...ADDITIONAL FLOODING IS POSSIBLE IF NOT
LIKELY ON THE TRIBUTARY RIVERS LATER IN THE WEEK INTO THE WEEKEND.
WILL CONTINUE HYDROLOGIC OUTLOOK PRODUCT ADDRESSING THE
RAIN/FLOODING THREATS LATER IN THE WEEK.
LOOK FOR WATER LEVELS ON THE MISSISSIPPI RIVER TO REMAIN NEARLY
STEADY OR GRADUALLY RISE THIS WEEK AS RUNOFF FROM RECENT RAINS AND
SNOWMELT MOVES DOWNSTREAM. THE ADDITIONAL RAINS ON WEDNESDAY THROUGH
THURSDAY WOULD CREATE ADDITIONAL RISES ON THE MISSISSIPPI
RIVER...BUT MOST OF THESE RISES FROM THE WED-THU RAINS EXPECTED NOT
TO SHOW UP IN THE MISSISSIPPI RIVER UNTIL EARLY NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...04
HYDROLOGY....DAS/RRS
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1210 PM MDT TUE APR 16 2013
.UPDATE...
&&
.SHORT TERM...TAKING A CLOSER LOOK AT THE LATEST MODELS...NOW
APPEARS THE DEVELOPMENT OF SNOW ACROSS THE PLAINS MAY BE DELAYED A BIT
LONGER OVERNIGHT...PERHAPS NOT UNTIL 10Z. WILL KEEP THE BETTER
POPS AND WEATHER TOWARDS THE WYOMING BODER.
.AVIATION...LATEST MODELS NOW SHOWING WINDS GO COUNTERCLOCKWISE
LATER THIS EVENING AND OVERNIGHT WHICH COULD BRING SOME LOW
STRATUS AND PERHAPS FOG ACROSS THE AREA AIRPORTS AFTER 06Z. IT
ALSO APPEARS THE DEVELOPMENT OF LIGHT SNOW MAY ALSO BE DELAYED.
LATEST TAFS INDICATE THIS LATEST CHANCE. STILL POTENTIAL FOR 2 TO
4 INCHES ACROSS DENVER AREA BY 00Z.
&&
.PREV DISCUSSION... /ISSUED 1059 AM MDT TUE APR 16 2013/
UPDATE...
SHORT TERM...STILL SEEMS FROM WEB CAMS THAT A FEW FLURRIES STILL
ONGOING ALONG THE CHEYENNE RIDGE AS WELL AS THE FOOTHILLS...THOUGH
HAVE BEEN ON THE DECREASE. ALSO APPEARS ANY FREEZING DRIZZLE
THREAT HAS ENDED. SOUTHEAST WINDS CURRENTLY CRANKING ACROSS
MUCH OF THE PLAINS...WITH SOME GUSTS AROUND 30 KTS FROM DENVER
AREA EASTWARD. WEAK CYCLONE NORTH OF DENVER KEEPING LIGHT
NORTHWEST WINDS NORTHWEST DENVER SUBURBS. OTHERWISE...SOUTHWEST
FLOW ALOFT PREVAILING THROUGH TONIGHT AS UPPER TROUGH DIGS INTO
THE GREAT BASIN. SOUTHEAST WINDS EXPECTED TO CONTINUE THROUGH THE
DAY ACROSS THE PLAINS WITH UPPER TROUGH OVER GREAT BASIN. AIRMASS
BECOMES SLIGHTLY UNSTABLE DURING THE AFTERNOON WITH LAPSE RATES
APPROACHING 8 C/KM OVER MOUNTAINS AND AROUND 7 C/KM IN THE MID
LEVELS ACROSS PLAINS. STILL SOME CHANCE OF SHOWERS THIS AFTERNOON
MAINLY OVER THE MOUNTAINS...WILL CONTINUE CURRENT POPS AND WEATHER
TRENDS THERE. AS FOR PLAINS...SCATTERED POPS MAY BE A BIT OVERDONE
THROUGH 00Z BASED ON LATEST RAP. BUT THERE WILL BE SOME INCREASE
IN MID LEVEL QG ASCENT WHICH COULD PROVIDE SOME CONVECTIVE
ELEMENTS WITH THE BEST CHANCE TO BE IN AND NEAR NORTHERN FOOTHILLS.
LATEST MODELS STILL POINTING TOWARD NORTHERN MOUNTAINS AND
NORTHERN FOOTHILLS TONIGHT FOR DECENT SNOW FALL WITH POTENTIAL FOR
JET DYNAMICS AND CSI. AT SOME POINT...MAY NEED AN ADVISORY FOR
ZONES 30..32 AND 34 TONIGHT AS CSI BANDS COULD SET UP THERE. WILL
ADDRESS THIS FOR THE AFTERNOON PACKAGE. OVERALL...CURRENT
FORECASTS SEEM ON TRACK...WITH PERHAPS A BIT MORE WIND NEEDED
ACROSS PLAINS. TEMPERATURES LOOK REASONABLE.
$$
,AVIATION...SOME FOG AND OR HAZE STILL FLOATING AROUND AREA
AIRPORTS...WILL KEEP A MENTION THROUGH 19Z. SOUTHEAST WINDS
CURRENTLY GUSTING TO AROUND 25-30 KTS AT KDEN AND KAPA...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON PER LATEST RAP AND HRRR.
CYCLONE NORTH OF DENVER TO PERSIST THROUGH THE DAY...SHOULD KEEP
LIGHT NORTHWEST WINDS AT KBJC. OTHERWISE...CURRENT TAF TRENDS SEEM
ON TRACK. CEILINGS TO GRADUALLY IMPROVE...STILL 5000-6000 FOOT
CEILINGS TO PREVAIL. A FEW SHOWERS POSSIBLE ALONG FOOTHILLS DURING
THE AFTERNOON AND EVENING. BETTER CHANCE FOR SNOW SHOWERS AT AREA
AIRPORTS AFTER MIDNIGHT TONIGHT. ACCUMULATION SNOW POSSIBLE DURING
THE DAY WEDNESDAY WHEN DEEPER UPSLOPE FLOW DEVELOPS WITH 2 TO 4
INCHES POSSIBLE BY 00Z.
PREV DISCUSSION... /ISSUED 428 AM MDT TUE APR 16 2013/
SHORT TERM...HEAVY SNOW BAND ALONG WITH THE UPPER LEVEL JET HAD
SHIFTED NORTH INTO WYOMING EARLY THIS MORNING. AS A RESULT...
EXISTING WINTER STORM HIGHLIGHTS HAVE BEEN CANCELLED. BEHIND
THIS...THERE WERE STILL SNOW SHOWERS MAINLY IN THE NORTHERN
MOUNTAINS AND NORTHERN FRONT RANGE FOOTHILLS. SOME FREEZING
DRIZZLE HAD ALSO DEVELOPED ACROSS THE PLAINS WITH MOIST LOW LEVEL
EASTERLY UPSLOPE FLOW. LACK OF SEEDERS ALOFT SHOULD KEEP THREAT OF
FREEZING DRIZZLE IN THE FORECAST THIS MORNING.
ATTENTION THEN TURNS TOWARD CONVECTIVE SHOWER DEVELOPMENT THIS
AFTERNOON WHICH SHOULD AFFECT MAINLY THE MOUNTAIN AREAS WHERE
INSTABILITY IS SUFFICIENT. BY THIS EVENING...THE VARIOUS SHORT AND
MEDIUM RANGE MODELS SUGGEST A DEEPER SOUTHEAST FLOW DEVELOPING
WHICH FAVORS THE NORTHERN FRONT RANGE FOOTHILLS FOR PRECIP. THE
POTENTIAL FOR HEAVY SNOWFALL LIKELY DEPENDS ON LOCATION OF UPPER
JET AND DRY SLOT...WHICH AT THIS TIME SHOULD BE JUST FAR ENOUGH
SOUTH TO BRING HEAVY SNOW THREAT BACK INTO THE NORTHERN TIER OF
MOUNTAINS AND THE LARIMER COUNTY FOOTHILLS LATER THIS AFTERNOON
THROUGH TONIGHT. AT THIS POINT...THE PROBABILITY IS HIGH ENOUGH TO
ISSUE ANOTHER WINTER STORM WARNING BEGINNING IN THOSE LOCATIONS
LATER THIS AFTERNOON. AGAIN...THERE WILL LIKELY BE ANOTHER VERY
SHARP CUTOFF OF SIGNIFICATION PRECIPITATION JUST SOUTH OF THE JET
SO SITUATION WILL NEED TO MONITORED CLOSELY.
ON THE PLAINS...LOW LEVEL SOUTHEAST FLOW WILL STRENGTHEN
CONSIDERABLY TODAY. HOWEVER...COOLER BOUNDARY LAYER FLOW SHOULD
REMAIN IN PLACE WITH PLENTY OF LOW LEVEL MOISTURE...CLOUDINESS...
AND SNOW IN AREAS THAT SAW THE HEAVY ACCUMULATIONS YESTERDAY. THE
SOUTHEAST FLOW AND SNOWPACK LOCATION SHOULD SET UP A STRONG DENVER
CYCLONE THIS AFTERNOON...KEEPING COLD AIR IN PLACE FROM THE
WESTERN SECTIONS OF DENVER NORTHWARD TO FORT COLLINS. COULD SEE A
FEW RAIN OR SNOW SHOWERS DRIFT OFF THE FRONT RANGE LATER THIS
AFTERNOON BUT BETTER CHANCE OF SNOW DEVELOPING WILL OCCUR LATER
TONIGHT AS MOISTURE BEGINS TO DEEPEN AHEAD OF DIGGING TROUGH.
LONG TERM...UPPER TROUGH DRAPED OVER THE GREAT BASIN WILL MOVE
SOUTHEAST WEDNESDAY AND SEND A COLD FRONT RACING DOWN NORTHEASTERN
COLORADO DURING THE MORNING. UPSLOPE FLOW WILL FORM AGAINST THE
FOOTHILLS DURING THE DAY TO KEEP SNOW GOING THROUGH THE AFTERNOON
AT LEAST. SNOW WILL SPREAD OVER THE PLAINS BEHIND THE FRONT AND
AS THE UPSLOPE DEEPENS. NORTH WINDS BEHIND THE FRONT...GUSTING 30 TO
40 MPH OVER THE PLAINS WILL REMAIN THROUGHOUT WEDNESDAY DAY TO
CREATE SOME AREAS OF BLOWING AND DRIFTING SNOW. RIGHT NOW WILL NOT
ISSUE ANY HIGHLIGHTS AS THERE MAY BE A PERIOD OF RAIN MIXED WITH
SNOW OVER THE PLAINS LIMITING THE AMOUNT OF BLOWING SNOW. OTHERWISE
ALL PRECIP IS EXPECTED TO BE SNOW AS 700 TEMPS OF -14 CELSIUS
SPREAD IN BEHIND THE FRONT. THE 700 MB LOW WILL TRANSITION OVER
THE COLORADO PLAINS SOMETIME LATE AFTERNOON INTO THE
EVENING...WHICH WILL BEGIN TO DIMINISH THE SNOW FROM NORTHWEST TO
SOUTHEAST. SNOW SHOULD BE DIMINISHED JUST AFTER SUNSET IN MOST
AREAS EXCEPT THE FAR EASTERN PLAINS AND SOME LIGHT SNOW OVER THE
MOUNTAINS...UNLESS THIS SYSTEM DIGS A LITTLE FARTHER SOUTH AND
DEEPER WHICH WOULD SLOW IT DOWN. OVERALL...AMOUNTS WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE ABOUT 2-5 INCHES OVER THE PLAINS AND
3-9 INCHES OVER THE MOUNTAINS...WITH THE LOWER AMOUNTS IN THE
VALLEYS. TEMPERATURES WEDNESDAY NIGHT WILL LIKELY BE IN THE TEENS
OVER THE PLAINS TO SINGLE DIGITS OVER THE MOUNTAINS.
THE UPPER LOW WILL MOVE EAST OF THE AREA THURSDAY. SHOULD SEE
SNOW SLOWLY DIMINISHING OVER THE MOUNTAINS AND A CHANCE OF SNOW
CONTINUING OVER THE FAR EASTERN PLAINS...BUT SHOULD BE DONE BY
LATE AFTERNOON. TEMPERATURES WILL BE WARMING SLIGHTLY BUT WILL
STILL BE AROUND 20 TO 30 DEGREES BELOW NORMAL. FRIDAY WILL
CONTINUE THE WARMING AND DRYING TREND AS A WEAK UPPER RIDGE BUILDS
OVERHEAD.
SATURDAY THROUGH MONDAY WILL FEATURE A COUPLE DISTURBANCES IN THE
NORTHWEST FLOW ALOFT TO BRING A RETURN TO UNSETTLED WEATHER. WILL
SEE AN INCREASE IN THE CHANCES OF PRECIPITATION AGAIN FOR THE
AREA. TEMPERATURES WILL BE BACK TOWARD NORMAL....BUT STILL
SLIGHTLY BELOW AVERAGE. THEREFORE WILL EXPECT MORE RAIN FOR THE
PLAINS AND CONTINUED RAIN MIXED WITH SNOW FOR THE MOUNTAINS.
AVIATION...AREAS OF IFR/LIFR CEILINGS EXPECTED ACROSS THE FRONT
RANGE AIRPORTS THIS MORNING ALONG WITH A THREAT OF LIGHT FREEZING
DRIZZLE GIVEN TEMP/MOISTURE PROFILE IN PLACE. IF WE SEE ANY SNOW
WE DO NOT SEE ANY THREAT OF ACCUMULATION WITH ONLY FLURRIES
POSSIBLE. CEILING SHOULD GRADUALLY LIFT TODAY AT KDEN AND KAPA
WITH POSSIBLE EAST/SOUTHEAST WINDS GUSTING TO AROUND 25KTS. KBJC
WILL LIKELY SEE LOWER PREVAILING CONDITIONS ON BACK SIDE OF
CYCLONE. CHANCE THAT WINDS GO BACK TO NORTH OR NORTHWEST AT KAPA
AND KDEN THIS AFTERNOON DEPENDING ON INTENSITY OF DENVER CYCLONE
THAT DEVELOPS. BEST CHANCE OF SNOW WILL BE AFTER MIDNIGHT TONIGHT
AND MAINLY WEDNESDAY WHEN DEEPER UPSLOPE FLOW OCCURS. COULD SEE
ANOTHER 2-5 INCHES OF SNOW LATE TONIGHT/WEDNESDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO MIDNIGHT MDT
WEDNESDAY NIGHT FOR COZ031-033-035.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1059 AM MDT TUE APR 16 2013
.UPDATE...
&&
.SHORT TERM...STILL SEEMS FROM WEB CAMS THAT A FEW FLURRIES STILL
ONGOING ALONG THE CHEYENNE RIDGE AS WELL AS THE FOOTHILLS...THOUGH
HAVE BEEN ON THE DECREASE. ALSO APPEARS ANY FREEZING DRIZZLE
THREAT HAS ENDED. SOUTHEAST WINDS CURRENTLY CRANKING ACROSS
MUCH OF THE PLAINS...WITH SOME GUSTS AROUND 30 KTS FROM DENVER
AREA EASTWARD. WEAK CYCLONE NORTH OF DENVER KEEPING LIGHT
NORTHWEST WINDS NORTHWEST DENVER SUBURBS. OTHERWISE...SOUTHWEST
FLOW ALOFT PREVAILING THROUGH TONIGHT AS UPPER TROUGH DIGS INTO
THE GREAT BASIN. SOUTHEAST WINDS EXPECTED TO CONTINUE THROUGH THE
DAY ACROSS THE PLAINS WITH UPPER TROUGH OVER GREAT BASIN. AIRMASS
BECOMES SLIGHTLY UNSTABLE DURING THE AFTERNOON WITH LAPSE RATES
APPROACHING 8 C/KM OVER MOUNTAINS AND AROUND 7 C/KM IN THE MID
LEVELS ACROSS PLAINS. STILL SOME CHANCE OF SHOWERS THIS AFTERNOON
MAINLY OVER THE MOUNTAINS...WILL CONTINUE CURRENT POPS AND WEATHER
TRENDS THERE. AS FOR PLAINS...SCATTERED POPS MAY BE A BIT OVERDONE
THROUGH 00Z BASED ON LATEST RAP. BUT THERE WILL BE SOME INCREASE
IN MID LEVEL QG ASCENT WHICH COULD PROVIDE SOME CONVECTIVE
ELEMENTS WITH THE BEST CHANCE TO BE IN AND NEAR NORTHERN FOOTHILLS.
LATEST MODELS STILL POINTING TOWARD NORTHERN MOUNTAINS AND
NORTHERN FOOTHILLS TONIGHT FOR DECENT SNOW FALL WITH POTENTIAL FOR
JET DYNAMICS AND CSI. AT SOME POINT...MAY NEED AN ADVISORY FOR
ZONES 30..32 AND 34 TONIGHT AS CSI BANDS COULD SET UP THERE. WILL
ADDRESS THIS FOR THE AFTERNOON PACKAGE. OVERALL...CURRENT
FORECASTS SEEM ON TRACK...WITH PERHAPS A BIT MORE WIND NEEDED
ACROSS PLAINS. TEMPERATURES LOOK REASONABLE.
$$
,AVIATION...SOME FOG AND OR HAZE STILL FLOATING AROUND AREA
AIRPORTS...WILL KEEP A MENTION THROUGH 19Z. SOUTHEAST WINDS
CURRENTLY GUSTING TO AROUND 25-30 KTS AT KDEN AND KAPA...WHICH
SHOULD CONTINUE THROUGH THE AFTERNOON PER LATEST RAP AND HRRR.
CYCLONE NORTH OF DENVER TO PERSIST THROUGH THE DAY...SHOULD KEEP
LIGHT NORTHWEST WINDS AT KBJC. OTHERWISE...CURRENT TAF TRENDS SEEM
ON TRACK. CEILINGS TO GRADUALLY IMPROVE...STILL 5000-6000 FOOT
CEILINGS TO PREVAIL. A FEW SHOWERS POSSIBLE ALONG FOOTHILLS DURING
THE AFTERNOON AND EVENING. BETTER CHANCE FOR SNOW SHOWERS AT AREA
AIRPORTS AFTER MIDNIGHT TONIGHT. ACCUMULATION SNOW POSSIBLE DURING
THE DAY WEDNESDAY WHEN DEEPER UPSLOPE FLOW DEVELOPS WITH 2 TO 4
INCHES POSSIBLE BY 00Z.
&&
.PREV DISCUSSION... /ISSUED 428 AM MDT TUE APR 16 2013/
SHORT TERM...HEAVY SNOW BAND ALONG WITH THE UPPER LEVEL JET HAD
SHIFTED NORTH INTO WYOMING EARLY THIS MORNING. AS A RESULT...
EXISTING WINTER STORM HIGHLIGHTS HAVE BEEN CANCELLED. BEHIND
THIS...THERE WERE STILL SNOW SHOWERS MAINLY IN THE NORTHERN
MOUNTAINS AND NORTHERN FRONT RANGE FOOTHILLS. SOME FREEZING
DRIZZLE HAD ALSO DEVELOPED ACROSS THE PLAINS WITH MOIST LOW LEVEL
EASTERLY UPSLOPE FLOW. LACK OF SEEDERS ALOFT SHOULD KEEP THREAT OF
FREEZING DRIZZLE IN THE FORECAST THIS MORNING.
ATTENTION THEN TURNS TOWARD CONVECTIVE SHOWER DEVELOPMENT THIS
AFTERNOON WHICH SHOULD AFFECT MAINLY THE MOUNTAIN AREAS WHERE
INSTABILITY IS SUFFICIENT. BY THIS EVENING...THE VARIOUS SHORT AND
MEDIUM RANGE MODELS SUGGEST A DEEPER SOUTHEAST FLOW DEVELOPING
WHICH FAVORS THE NORTHERN FRONT RANGE FOOTHILLS FOR PRECIP. THE
POTENTIAL FOR HEAVY SNOWFALL LIKELY DEPENDS ON LOCATION OF UPPER
JET AND DRY SLOT...WHICH AT THIS TIME SHOULD BE JUST FAR ENOUGH
SOUTH TO BRING HEAVY SNOW THREAT BACK INTO THE NORTHERN TIER OF
MOUNTAINS AND THE LARIMER COUNTY FOOTHILLS LATER THIS AFTERNOON
THROUGH TONIGHT. AT THIS POINT...THE PROBABILITY IS HIGH ENOUGH TO
ISSUE ANOTHER WINTER STORM WARNING BEGINNING IN THOSE LOCATIONS
LATER THIS AFTERNOON. AGAIN...THERE WILL LIKELY BE ANOTHER VERY
SHARP CUTOFF OF SIGNIFICATION PRECIPITATION JUST SOUTH OF THE JET
SO SITUATION WILL NEED TO MONITORED CLOSELY.
ON THE PLAINS...LOW LEVEL SOUTHEAST FLOW WILL STRENGTHEN
CONSIDERABLY TODAY. HOWEVER...COOLER BOUNDARY LAYER FLOW SHOULD
REMAIN IN PLACE WITH PLENTY OF LOW LEVEL MOISTURE...CLOUDINESS...
AND SNOW IN AREAS THAT SAW THE HEAVY ACCUMULATIONS YESTERDAY. THE
SOUTHEAST FLOW AND SNOWPACK LOCATION SHOULD SET UP A STRONG DENVER
CYCLONE THIS AFTERNOON...KEEPING COLD AIR IN PLACE FROM THE
WESTERN SECTIONS OF DENVER NORTHWARD TO FORT COLLINS. COULD SEE A
FEW RAIN OR SNOW SHOWERS DRIFT OFF THE FRONT RANGE LATER THIS
AFTERNOON BUT BETTER CHANCE OF SNOW DEVELOPING WILL OCCUR LATER
TONIGHT AS MOISTURE BEGINS TO DEEPEN AHEAD OF DIGGING TROUGH.
LONG TERM...UPPER TROUGH DRAPED OVER THE GREAT BASIN WILL MOVE
SOUTHEAST WEDNESDAY AND SEND A COLD FRONT RACING DOWN NORTHEASTERN
COLORADO DURING THE MORNING. UPSLOPE FLOW WILL FORM AGAINST THE
FOOTHILLS DURING THE DAY TO KEEP SNOW GOING THROUGH THE AFTERNOON
AT LEAST. SNOW WILL SPREAD OVER THE PLAINS BEHIND THE FRONT AND
AS THE UPSLOPE DEEPENS. NORTH WINDS BEHIND THE FRONT...GUSTING 30 TO
40 MPH OVER THE PLAINS WILL REMAIN THROUGHOUT WEDNESDAY DAY TO
CREATE SOME AREAS OF BLOWING AND DRIFTING SNOW. RIGHT NOW WILL NOT
ISSUE ANY HIGHLIGHTS AS THERE MAY BE A PERIOD OF RAIN MIXED WITH
SNOW OVER THE PLAINS LIMITING THE AMOUNT OF BLOWING SNOW. OTHERWISE
ALL PRECIP IS EXPECTED TO BE SNOW AS 700 TEMPS OF -14 CELSIUS
SPREAD IN BEHIND THE FRONT. THE 700 MB LOW WILL TRANSITION OVER
THE COLORADO PLAINS SOMETIME LATE AFTERNOON INTO THE
EVENING...WHICH WILL BEGIN TO DIMINISH THE SNOW FROM NORTHWEST TO
SOUTHEAST. SNOW SHOULD BE DIMINISHED JUST AFTER SUNSET IN MOST
AREAS EXCEPT THE FAR EASTERN PLAINS AND SOME LIGHT SNOW OVER THE
MOUNTAINS...UNLESS THIS SYSTEM DIGS A LITTLE FARTHER SOUTH AND
DEEPER WHICH WOULD SLOW IT DOWN. OVERALL...AMOUNTS WEDNESDAY AND
WEDNESDAY NIGHT LOOK TO BE ABOUT 2-5 INCHES OVER THE PLAINS AND
3-9 INCHES OVER THE MOUNTAINS...WITH THE LOWER AMOUNTS IN THE
VALLEYS. TEMPERATURES WEDNESDAY NIGHT WILL LIKELY BE IN THE TEENS
OVER THE PLAINS TO SINGLE DIGITS OVER THE MOUNTAINS.
THE UPPER LOW WILL MOVE EAST OF THE AREA THURSDAY. SHOULD SEE
SNOW SLOWLY DIMINISHING OVER THE MOUNTAINS AND A CHANCE OF SNOW
CONTINUING OVER THE FAR EASTERN PLAINS...BUT SHOULD BE DONE BY
LATE AFTERNOON. TEMPERATURES WILL BE WARMING SLIGHTLY BUT WILL
STILL BE AROUND 20 TO 30 DEGREES BELOW NORMAL. FRIDAY WILL
CONTINUE THE WARMING AND DRYING TREND AS A WEAK UPPER RIDGE BUILDS
OVERHEAD.
SATURDAY THROUGH MONDAY WILL FEATURE A COUPLE DISTURBANCES IN THE
NORTHWEST FLOW ALOFT TO BRING A RETURN TO UNSETTLED WEATHER. WILL
SEE AN INCREASE IN THE CHANCES OF PRECIPITATION AGAIN FOR THE
AREA. TEMPERATURES WILL BE BACK TOWARD NORMAL....BUT STILL
SLIGHTLY BELOW AVERAGE. THEREFORE WILL EXPECT MORE RAIN FOR THE
PLAINS AND CONTINUED RAIN MIXED WITH SNOW FOR THE MOUNTAINS.
AVIATION...AREAS OF IFR/LIFR CEILINGS EXPECTED ACROSS THE FRONT
RANGE AIRPORTS THIS MORNING ALONG WITH A THREAT OF LIGHT FREEZING
DRIZZLE GIVEN TEMP/MOISTURE PROFILE IN PLACE. IF WE SEE ANY SNOW
WE DO NOT SEE ANY THREAT OF ACCUMULATION WITH ONLY FLURRIES
POSSIBLE. CEILING SHOULD GRADUALLY LIFT TODAY AT KDEN AND KAPA
WITH POSSIBLE EAST/SOUTHEAST WINDS GUSTING TO AROUND 25KTS. KBJC
WILL LIKELY SEE LOWER PREVAILING CONDITIONS ON BACK SIDE OF
CYCLONE. CHANCE THAT WINDS GO BACK TO NORTH OR NORTHWEST AT KAPA
AND KDEN THIS AFTERNOON DEPENDING ON INTENSITY OF DENVER CYCLONE
THAT DEVELOPS. BEST CHANCE OF SNOW WILL BE AFTER MIDNIGHT TONIGHT
AND MAINLY WEDNESDAY WHEN DEEPER UPSLOPE FLOW OCCURS. COULD SEE
ANOTHER 2-5 INCHES OF SNOW LATE TONIGHT/WEDNESDAY.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO MIDNIGHT MDT
WEDNESDAY NIGHT FOR COZ031-033-035.
&&
$$
SHORT TERM...D-L
LONG TERM....KRIEDERMAN
AVIATION...D-L
AREA FORECAST DISCUSSION...UPDATED
NWS PEACHTREE CITY GA
212 PM EDT TUE APR 16 2013
.PREV DISCUSSION... /ISSUED 1147 AM EDT TUE APR 16 2013/
UPDATE...
HAVE MADE SEVERAL TWEAKS TO THE GRIDS. MAIN CHANGES HAVE BEEN TO
INCREASE DEWPOINTS AND POPS...ESPECIALLY FOR THIS AFTERNOON. ALL
HI-RES MODELS INDICATING AN INCREASE IN CONVECTIVE COVERAGE
BETWEEN 18-00Z. SURFACE DEWPOINTS ARE ACTUALLY QUITE A BIT HIGHER
THAN FORECAST. LIMITING FACTOR WILL BE CAPE IN THE MIDLEVELS...AS
NOTED ON THE 12Z KFFC SOUNDING WITH A WEAK WARM NOSE AT ABOUT
640MB. EVEN MODIFYING THIS WARM NOSE /DECREASE TO 1C INSTEAD OF
3C/ ONLY YIELDS ABOUT 500 J/KG SBCAPE. HOWEVER...WITH SUCH A
STRONG SHORTWAVE PUSHING INTO THE AREA AS EVIDENT ON WATER VAPOR
LOOPS...THE LIFTING MAY SERVE TO COOL THAT WARM NOSE FURTHER. KBMX
HAS A HINT OF THE WARM NOSE AND KOHX DOES NOT SHOW IT...SO WITH
THE WESTERLIES ALOFT ADVECTING THAT AIRMASS THIS WAY IT WILL BE A
MATTER OF THESE COMPETING FACTORS. SO THAT SAID...HAVE INCREASED
POPS FOR NOW TO CHANCE...THOUGH IF YOU BELIEVE THE HRRR POPS MAY
NEED TO BE INCREASED SOME MORE FOR THIS AFTERNOON...AND INCREASED
THUNDER WORDING TO CHANCE /SCATTERED/ AS WELL. NOT TOTALLY SOLD ON
THE HIGHER COVERAGE THAT THE HRRR IS INDICATING BUT AT LEAST HAVE
TRENDED IN THAT DIRECTION. UPDATED PRODUCTS WILL BE OUT SHORTLY.
TDP
PREV DISCUSSION... /ISSUED 735 AM EDT TUE APR 16 2013/
SHORT TERM /TODAY THROUGH WEDNESDAY/...
WEAK UPPER-LEVEL RIDGING PERSISTS OVER THE REGION THROUGH WEDNESDAY.
INFLUENCE OF THE RIDGE WILL LIKELY KEEP CHANCES FOR AFTERNOON
CONVECTION AT A MINIMUM TODAY ALTHOUGH INSTABILITY IS SUFFICIENT FOR
A MENTION OF A SLIGHT CHANCE OVER THE WESTERN THIRD TO HALF OF NORTH
AND CENTRAL GEORGIA. YESTERDAY EVENINGS SOUNDING SHOWS SIGNIFICANT
COOLING WOULD BE NEEDED IN THE 700-400MB LEVELS FOR ANY SIGNIFICANT
SEVERE WEATHER THREAT...AND THAT DOES NOT APPEAR TO BE LIKELY TODAY.
BY WEDNESDAY THE RIDGE AXIS IS SHIFTING EAST OF THE STATE ALLOWING
FOR CHANCE POPS OVER THE WEST AND SLIGHT CHANCE POPS TO SPREAD EAST
OVER THE REMAINDER OF THE FORECAST AREA. ALTHOUGH AN ISOLATED STRONG
STORM OR TWO CANNOT BE RULED OUT...INSTABILITY IS EXPECTED TO REMAIN
TOO MARGINAL FOR A MENTION OF SEVERE THUNDERSTORMS AT THIS TIME.
20
LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
LONG TERM PERIOD BEGINS WITH DEVELOPING SOUTHERLY FLOW WHICH
SHOULD ACT TO SHUNT MOISTURE AXIS NORTH OF THE AREA. WILL STILL
CARRY RESIDUAL 20 POPS FOR THE NORTH INTO THE FIRST PART OF THE
OVERNIGHT PERIOD BUT QUICKLY DISSIPATE AFTER 06Z THU. ANOTHER
ROUND POSSIBLE THU BUT OVERALL TRENDS ARE FOR LESS DIURNAL
COVERAGE GIVEN SLIGHTLY LESS MOISTURE AND CORRESPONDINGLY LESS
INSTABILITY.
MODELS STILL IN GOOD AGREEMENT WITH EXCELLENT RUN TO RUN
CONSISTENCY WRT NEXT STORM SYSTEM WHICH LOOKS TO EJECT OUT OF THE
CENTRAL PLAINS THURSDAY AND MOVE INTO THE MID MISSISSIPPI VALLEY
THURSDAY NIGHT. TIMING FOR THE LOCAL AREA INDICATES BAND OF
SHOWERS AND SCATTERED THUNDERSTORMS REACHING NW GEORGIA JUST PRIOR
TO 12Z FRIDAY. INSTABILITY STILL LOOKS MARGINAL FOR THIS EVENT
WITH ONLY A NARROW SLIVER OF 200J/KG TO 400J/KG SURFACE BASED CAPE
TO WORK WITH FOR NORTHERN SECTIONS. SLIGHTLY MORE INSTABILITY TO
THE SOUTH WITH THIS SYSTEM AND WILL HAVE INCREASED THUNDER CHANCES
ROUGHLY FROM THE ATLANTA METRO SOUTHWARD. 850MB JET IS VERY
IMPRESSIVE WITH THIS SYSTEM WITH NEARLY 90 KTS INDICATED FOR THE
OHIO VALLEY. OUR AREA ONLY GETS THE SOUTHERN END OF THIS BUT STILL
GOOD ENOUGH FOR 65 KTS FOR NW CORNER. INSTABILITY LOOKS TO BE
AHEAD OF MAIN WIND CORE SO TIMING MAY NOT LINE UP FOR THIS ONE.
REGARDLESS...925MB WINDS ARE 50KTS OVER THE LOCAL AREA WHICH
SHOULD RESULT IN NEAR SEVERE WINDS EVEN WITH THE ABSENCE OF ROBUST
CONVECTION. WILL BEGIN TO RAMP UP WORDING IN HWO.
ONCE SYSTEM CLEARS...BENIGN BUT COLD CONDITIONS FOR THIS TIME OF
YEAR WITH LOWS RETURNING TO THE 30S.
DEESE
&&
.AVIATION...
18Z UPDATE...
VFR THIS AFTERNOON WITH SHRA OR POSSIBLE TSRA DEVELOPING MAINLY
FOR THE METRO TAFS...THOUGH WITH SOME QUESTIONS ABOUT COVERAGE
HAVE INCLUDED VCSH WITH A TEMPO TSRA. EXPECT THIS ACTIVITY TO
DIMINISH AFTER 00Z TONIGHT. CIGS SHOULD DROP AGAIN AFTER 08-09Z IN
THE MORNING...WITH SOME GUIDANCE HINTING AT IFR. HAVE INCLUDED LOW
MVFR FOR NOW BUT THIS WILL NEED TO BE REEVALUATED. MVFR FOG LIKELY
AT MOST SITES EXCEPT ATL AS WELL. EXPECT A LIFTING/CLEARING TREND
LATE WEDNESDAY MORNING. INCLUDED PROB30 TSRA FOR ATL WEDNESDAY
AFTERNOON. E TO SE WINDS GENERALLY 5-10KT THROUGH THE PERIOD
EXCEPT LIGHTER OVERNIGHT.
//ATL CONFIDENCE...18Z UPDATE...
MEDIUM ON OCCURRENCE OF TSRA THIS AFTERNOON...LOW ON IMPACTS TO ATL.
MEDIUM ON CIGS WEDNESDAY MORNING.
HIGH ON ALL OTHER ELEMENTS.
TDP
&&
.PRELIMINARY POINT TEMPS/POPS...
ATHENS 79 59 82 59 / 20 10 30 20
ATLANTA 78 63 81 62 / 40 20 30 20
BLAIRSVILLE 76 57 77 58 / 30 20 40 20
CARTERSVILLE 81 60 82 59 / 40 20 30 20
COLUMBUS 83 64 85 63 / 20 10 20 20
GAINESVILLE 78 61 80 61 / 30 20 30 20
MACON 82 59 83 58 / 20 5 20 10
ROME 81 60 82 60 / 40 20 30 20
PEACHTREE CITY 78 59 82 60 / 40 20 30 20
VIDALIA 81 62 83 62 / 5 0 10 10
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1228 PM CDT TUE APR 16 2013
.DISCUSSION...
ISSUED 1030 AM CDT TUE APR 16 2013
COLD FRONT HAS PUSHED JUST SOUTH OF OUR CWA...BUT WAS CLOSE ENOUGH
TO LAWRENCEVILLE THAT TEMPERATURES THERE ARE STILL IN THE MID 60S.
MOSTLY SEEING 40S ELSEWHERE WITH SOME LOWER 50S. ELEVATED
CONVECTION NORTH OF THE BOUNDARY HAS BEEN INCREASING OVER CENTRAL
ILLINOIS AS IT MOVES OUT OF MISSOURI...AND COVERED MOST OF THE
CWA AT 1030 AM EXCEPT FOR THE FAR NORTHWEST AND FAR SOUTHEAST.
LATEST RAP MODEL SHOWING THE SCATTERED CONVECTION CONTINUING
ACROSS MUCH OF THE CWA INTO THIS AFTERNOON...WITH LESS COVERAGE
NORTHWEST OF THE ILLINOIS RIVER. HAVE SENT OUT SOME ZONE/GRID
UPDATES TO INCREASE THE RAIN CHANCES TODAY...WITH SOME MINOR
ADJUSTMENTS TO TEMPERATURES REQUIRED AS WELL.
GEELHART
&&
.HYDROLOGY...
ISSUED 1030 AM CDT TUE APR 16 2013
EARLY LOOK AT 12Z MODEL RUNS CONTINUE TO SUPPORT AN INCREASING
POOL OF MOISTURE INTO ILLINOIS ON WEDNESDAY...WITH PRECIPITABLE
WATER VALUES UP TO AROUND 1.5 TO 1.6 INCHES BY LATE WEDNESDAY
AFTERNOON...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE NORMAL.
BULK OF THE HEAVIEST RAIN EXPECTED WEDNESDAY NIGHT THROUGH
THURSDAY NIGHT. LATEST QPF FORECAST SHOWS OVER 3 INCHES ACROSS A
LARGE PART OF THE FORECAST AREA THROUGH FRIDAY...WITH 2-3 INCHES
ACROSS ABOUT THE SOUTHEAST THIRD. PROBABILITY FORECASTS FROM THE
WEATHER PREDICTION CENTER SHOW A 50-60 PERCENT CHANCE OF RECEIVING
AT LEAST 2.5 INCHES OF RAIN FROM WEDNESDAY EVENING THROUGH
THURSDAY EVENING.
CURRENTLY ONLY THE ILLINOIS RIVER AT HAVANA AND BEARDSTOWN ARE IN
FLOOD...BUT MORE FLOODING IS EXPECTED ACROSS MANY RIVERS. STANDARD
RIVER FORECASTS ONLY ACCOUNT FOR 24-HOUR QPF...BUT RFC CONTINGENCY
FORECASTS BASED ON 72-HOUR QPF SHOW POTENTIAL FOR MODERATE OR
MAJOR FLOODING IN SOME CASES.
HAVE SENT OUT A HYDROLOGIC OUTLOOK TO ADDRESS THE HEAVY RAIN
POTENTIAL...WHILE REMAINING MODEL GUIDANCE IS DIGESTED TO
DETERMINE THE POTENTIAL FOR ANY FLOOD WATCHES WITH THE AFTERNOON
FORECAST PACKAGE.
GEELHART
&&
.AVIATION...
ISSUED 1224 PM CDT TUE APR 16 2013
BAND OF THUNDERSTORMS WILL CONTINUE TO AFFECT KCMI AND KDEC FOR
ANOTHER HOUR OR TWO...WITH MVFR CEILINGS/VISIBILITIES. GENERAL
TREND OTHERWISE WILL BE FOR SCATTERED SHOWERS TO CONTINUE THIS
AFTERNOON...WITH CEILINGS GENERALLY VFR FOR A TIME. HOWEVER...
ADDITIONAL CONVECTIVE DEVELOPMENT WILL BRING MVFR CONDITIONS AGAIN
THIS EVENING. BASED ON SOUNDINGS...CEILINGS AFTER 06Z MAY FALL TO
AROUND 1000 FEET OR SO...WHICH WILL LINGER A GOOD PART OF
WEDNESDAY MORNING. HOWEVER...A WARM FRONT WILL LIFT NORTHWARD
ACROSS THE TAF SITES TOWARD LATE MORNING...RAPIDLY LIFTING
CEILINGS BACK INTO VFR RANGE.
GEELHART
&&
.PREV DISCUSSION...
ISSUED 330 AM CDT TUE APR 16 2013
VERY UNSETTLED WEATHER PATTERN TO OCCUR THROUGH FRIDAY ACROSS
CENTRAL AND SE IL WITH PERIODS OF SHOWERS AND THUNDERSTORM GIVING
2-4 INCHES OF RAIN BY FRIDAY WITH THE HEAVIEST AMOUNTS FROM I-55 NW.
SPC ALSO CONTINUES SLIGHT RISK OF SEVERE STORMS ACROSS AREAS WEST OF
I-57 WED NIGHT AND ACROSS MUCH OF REGION THU/THU EVENING. LIKE
YESTERDAYS MODEL RUNS...THE 00Z MODEL SUITE TODAY CONTINUES SLOWER
TREND WITH POTENT COLD FRONT MOVING EASTWARD ACROSS IL THU
AFTERNOON/EVENING.
SHORT TERM...TODAY THROUGH FRIDAY
MCS FROM CENTRAL MO NE ACROSS CENTRAL IL INTO NW INDIANA HAS
GRADUALLY BEEN WEAKENING THE PAST HOUR OR SO. A BROKEN LINE OF
THUNDERSTORMS WITH HEAVY RAINS WAS ALONG SE EDGE OF THIS MCS FROM
TAYLORVILLE AND SHELBYVILLE TO TUSCOLA AND CHRISMAN. HAD A FEW
REPORTS OF HAIL BETWEEN MIDNIGHT AND 1 AM OVER PARTS OF SANGAMON AND
LOGAN COUNTIES. COLD FRONT HAD SAGGED SLOWLY INTO SE IL...SE OF
I-70 EARLY THIS MORNING BEING PULLED SE BY MCS AND 1012 MB LOW
PRESSURE NEAR INDY. COLD FRONT EXTENDED SW TO A 1000 MB LOW
PRESSURE OVER EASTERN NM. BROAD SW UPPER LEVEL FLOW OVER THE
COUNTRY HAS BEEN SLOWLY DOWN THE SE PROGRESSION OF THIS COLD FRONT.
RADAR ESTIMATED 1.5-2.5 INCHES OF RAIN ALONG AND JUST SE OF A
RUSHVILLE TO BLOOMINGTON LINE.
CONVECTION TO CONTINUE TO WEAKEN DURING THE MORNING WITH AS LOW
LEVEL JET THAT PEAKED AROUND 40 KTS WEAKENS. BEST CHANCES OF
SHOWERS AND THUNDERSTORMS TODAY SHIFTS INTO SE IL CLOSER TO
FRONTAL BOUNDARY WHICH CONTINUES TO SLOWLY SAG SOUTHWARD TODAY...
WHILE DRIER AND COOLER TO THE NORTH. SCATTERED SHOWERS AND
THUNDERSTORMS POSSIBLE THIS AFTERNOON ESPECIALLY FROM I-72 SOUTH.
HIGHS TODAY RANGE FROM THE MID 50S OVER THE IL RIVER VALLEY FROM
I-55 NW TO THE UPPER 60S TO NEAR 70F IN FAR SE IL ALONG HIGHWAY
50.
INCREASING LOW LEVEL JET TO INCREASE CHANCES OF SHOWERS AND
THUNDERSTORMS TONIGHT ESPECIALLY OVERNIGHT WHEN SPC HAS SLIGHT
CHANCE OF SEVERE OVER SE IL AND SW OF SPRINGFIELD. MAINLY A HAIL
THREAT SW OF SPRINGFIELD WHILE HAIL AND WIND IN FAR SE IL NEAR
HIGHWAY 50.
FRONTAL BOUNDARY TO BEGIN TO LIFT BACK NORTHWARD OVER CENTRAL IL
WED WITH SHOWERS AND THUNDERSTORMS LIKELY ESPECIALLY NW AREAS.
HIGHS RANGE FROM THE MID 60S NW OF THE IL RIVER TO THE UPPER 70S
AND LOWER 80S ACROSS SE IL. BEST CHANCES OF SHOWERS AND
THUNDERSTORMS OVER THE AREAS WED NIGHT THROUGH THU NIGHT AS STRONG
COLD FRONT MOVES EASTWARD OVER IL THU AFTERNOON/EVENING. SPC HAS
MUCH OF AREA IN A SLIGHT RISK OF SEVERE STORMS DURING THIS TIME
FOR DAMAGING WIND GUSTS WITH A SQUALL LINE AND LARGE HAIL ALSO
A RISK. HEAVIEST RAINS TO OCCUR WED NIGHT THROUGH THU NIGHT WITH
2-4 INCHES POSSIBLE AND HEAVIEST OVER THE IL RIVER VALLEY. HIGHS
THU TRICKING DEPENDING ON HOW FAST COLD FRONT MOVES INTO AREA...
BUT UPPER 70S AND LOWER 80S POSSIBLE OVER EASTERN IL ESPECIALLY
NEAR THE WABASH RIVER WHILE TEMPS EXPECTED TO FALL OVER THE IL
RIVER VALLEY THU AFTERNOON.
COLD FRONT PASSES EAST OF IL FRI BUT STRONG UPPER LEVEL TROF
MOVING INTO AREA TO CONTINUE LOW CLOUDS ALONG WITH A GOOD CHANCE
OF SHOWERS. COULD BE COLD ENOUGH FOR A CHANCE OF LIGHT SNOW
SHOWERS TOO NORTH OF PEORIA FRIDAY MORNING THOUGH BEST CHANCES OF
SNOW SHOWERS IS FURTHER NW OVER NW IL. HIGHS FRI ONLY 45-50 OVER
CENTRAL IL AND LOWER 50S IN SE IL.
LONG TERM...FRIDAY NIGHT THROUGH TUESDAY
CANADIAN HIGH PRESSURE TO BUILD INTO IL SAT AND BRING DRY BUT COOL
WEATHER FRIDAY NIGHT THRU SAT NIGHT. LOWS FRIDAY NIGHT IN THE
LOWER 30S CENTRAL IL AND MID 30S SE IL. HIGHS SAT IN THE LOW TO
MID 50S. LOWS SAT NIGHT IN THE MID TO UPPER 30S. CANADIAN HIGH
DRIFTING INTO THE EASTERN GREAT LAKES REGION SUNDAY TO ALLOW TEMPS
TO MODIFY INTO THE UPPER 50S AND LOWER 60S SUNDAY AND INTO THE LOW
TO MID 60S MONDAY. A COLD FRONT APPROACHING THE MS VALLEY MONDAY
TO GIVE CENTRAL AND WESTERN IL CHANCES OF SHOWERS AND ISOLATED
THUNDERSTORMS WHICH CONTINUES ACROSS AREA MONDAY NIGHT/TUE AS COLD
FRONT SWEEPS THROUGH BRINGING COOLER AIR TUE ON BREEZY NW WINDS.
ECMWF AND GFS MODELS FAIRLY SIMILAR WITH THIS WEATHER SYSTEM EARLY
NEXT WEEK.
07
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
631 PM EDT TUE APR 16 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE LIKELY TODAY AND TONIGHT AS A COLD
FRONT SLIDES ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
JUST MADE A QUICK UPDATE TO BETTER REFLECT WARMING TEMPERATURES IN
THE LOCATIONS AHEAD OF THE COLD FRONT THAT ARE SEEING BREAKS IN
CLOUD COVER. ADJUSTED POP TIMING A LITTLE FOR THE OVERNIGHT HOURS
BASED ON THE MOST RECENT HRRR SINCE IT SEEMS TO BE REFLECTING THE
CURRENT SITUATION QUITE WELL. OTHERWISE...NO OTHER CHANGES.
PREVIOUS DISCUSSION FOLLOWS...
WHILE AMPLE CLOUD COVER HAS REMAINED ACROSS THE REGION
TODAY...SURFACE TEMPERATURES AND DEWOPINTS OUT AHEAD OF THE COLD
FRONT HAVE STILL REBOUNDED QUITE NICELY ALLOWING FOR AN INCREASE
IN CAPE TO NEAR 1000J/KG FOR SOUTHERN PORTIONS OF THE REGION. THIS
IS EXPECTED TO CONTINUE AND WHILE THE BETTER INSTABILITY AND SHEAR
CURRENTLY DO NOT LINE UP WELL...THIS COULD CHANGE AS ANOTHER
SHORTWAVE APPROACHES THE COLD FRONT AS IT GRADUALLY SAGS
SOUTHWARD. GIVEN THIS...CANNOT RULE OUT A FEW THUNDERSTORMS
MAINTAINING THEMSELVES TO SEVERE LEVELS. THUS...AFTER
COLLABORATION WITH SURROUNDING OFFICES AND THE STORM PREDICTION
CENTER...A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED THROUGH 11PM
THIS EVENING.
BASED ON THE MOST RECENT HRRR AND OTHER HI-RES MODELS...THE LINE
OF SHOWERS SHOULD REACH THE SOUTHERN HALF OF THE REGION OVERNIGHT
BEFORE THE BOUNDARY STALLS OVER SOMEWHERE ALONG THE MASON DIXON
LINE.
WARM NR TERM TEMPS WERE FORECAST USING A BLEND OF GUIDANCE AND THE
LATEST OBSERVATION TRENDS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
STALLED FRONT WILL DRIFT NORTHWARD WED...BUT APPEARS TO ALMOST
WASH OUT AS RIDGES STRENGTHENS OVER THE UPPER OHIO VALLEY. THE
FRONT WILL BE FORCED NORTHWARD AS THE MAIN SFC LOW SWINGS OUT OF
THE SOUTHERN ROCKIES AND INTO THE SOUTHERN PLAINS. THE HEIGHT
RISES ARE IN RESPONSE TO A LARGE TROUGH WHICH WILL DIG INTO THE
ROCKIES. WILL INCLUDE THE CHC FOR SHOWERS AND STORMS WED AS AN
UPPER LEVEL WAVE WILL CREST THE TOP OF THE BUILDING RIDGE.
AREA WILL LIE IN THE WARM SECTOR BY WED NIGHT AND REMAIN THERE
THROUGH THU. EXPECT WED NIGHT TO REMAIN DRY WITH SCT SHOWERS/STORMS
POSSIBLE THU WITH DAYTIME HEATING.
UNDER SOUTHERLY FLOW...TEMPS WILL RISE ABOVE NORMAL ON THU.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A CDFNT SHOULD BE EXITING THE RGN FRI EVE...WITH ANY SHRA/TS CHCS
ENDG FRI NGT. AN UPR LVL TROF IS EXPD TO MOVE ACRS THE GT LKS RGN
SAT...BUT MOISTURE IS LMTD SO KEPT FCST DRY ATTM. HIGH PRES BLDS IN
SAT NGT THRU MON NGT UNTIL A CDFNT APRCHS FM THE W ON TUE WITH
ANOTHER CHC FOR SHRA/TS. TEMPS SHOULD BE BLO AVG LVLS OVR THE
WKEND...WITH A WRMG TREND ERLY NXT WK.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING. THINK THAT A
BRIEF PERIOD OF TSRA REMAINS POSSIBLE WITH THE FRONT AS IT PASSES.
GUSTY SW WNDS LATE THIS AFTN SHOULD SHFT TO THE W AND THEN N THIS
EVE AFT FROPA. MVFR CIGS WILL REMAIN A POSSIBILITY AT FKL/DUJ INTO
THE EVE...OTRW GENL LOW END VFR CIGS FCST OUTSIDE OF ANY PCPN ACRS
THE RGN.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
THE FNT WL MOVE BACK N AS A WRMFNT WED NGT INTO THU WITH BRF RESTRNS
PSBL. A CDFNT WL MOVE E ACRS THE RGN FRI WITH SHRA/TS RESTRNS BEFORE
HI PRES BLDS IN SAT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
431 PM EDT TUE APR 16 2013
.SYNOPSIS...
SHOWERS AND THUNDERSTORMS ARE LIKELY TODAY AND TONIGHT AS A COLD
FRONT SLIDES ACROSS THE REGION.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
WHILE AMPLE CLOUD COVER HAS REMAINED ACROSS THE REGION TODAY...SURFACE
TEMPERATURES AND DEWOPINTS OUT AHEAD OF THE COLD FRONT HAVE STILL
REBOUNDED QUITE NICELY ALLOWING FOR AN INCREASE IN CAPE TO NEAR
1000J/KG FOR SOUTHERN PORTIONS OF THE REGION. THIS IS EXPECTED TO
CONTINUE AND WHILE THE BETTER INSTABILITY AND SHEAR CURRENTLY DO
NOT LINE UP WELL...THIS COULD CHANGE AS ANOTHER SHORTWAVE
APPROACHES THE COLD FRONT AS IT GRADUALLY SAGS SOUTHWARD. GIVEN
THIS...CANNOT RULE OUT A FEW THUNDERSTORMS MAINTAINING THEMSELVES
TO SEVERE LEVELS. THUS...AFTER COLLABORATION WITH SURROUNDING
OFFICES AND THE STORM PREDICTION CENTER...A SEVERE THUNDERSTORM
WATCH HAS BEEN ISSUED THROUGH 11PM THIS EVENING.
BASED ON THE MOST RECENT HRRR AND OTHER HI-RES MODELS...THE LINE
OF SHOWERS SHOULD REACH THE SOUTHERN HALF OF THE REGION OVERNIGHT
BEFORE THE BOUNDARY STALLS OVER SOMEWHERE ALONG THE MASON DIXON
LINE.
WARM NR TERM TEMPS WERE FORECAST USING A BLEND OF GUIDANCE AND THE
LATEST OBSERVATION TRENDS.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
STALLED FRONT WILL DRIFT NORTHWARD WED...BUT APPEARS TO ALMOST
WASH OUT AS RIDGES STRENGTHENS OVER THE UPPER OHIO VALLEY. THE
FRONT WILL BE FORCED NORTHWARD AS THE MAIN SFC LOW SWINGS OUT OF
THE SOUTHERN ROCKIES AND INTO THE SOUTHERN PLAINS. THE HEIGHT
RISES ARE IN RESPONSE TO A LARGE TROUGH WHICH WILL DIG INTO THE
ROCKIES. WILL INCLUDE THE CHC FOR SHOWERS AND STORMS WED AS AN
UPPER LEVEL WAVE WILL CREST THE TOP OF THE BUILDING RIDGE.
AREA WILL LIE IN THE WARM SECTOR BY WED NIGHT AND REMAIN THERE
THROUGH THU. EXPECT WED NIGHT TO REMAIN DRY WITH SCT SHOWERS/STORMS
POSSIBLE THU WITH DAYTIME HEATING.
UNDER SOUTHERLY FLOW...TEMPS WILL RISE ABOVE NORMAL ON THU.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A CDFNT SHOULD BE EXITING THE RGN FRI EVE...WITH ANY SHRA/TS CHCS
ENDG FRI NGT. AN UPR LVL TROF IS EXPD TO MOVE ACRS THE GT LKS RGN
SAT...BUT MOISTURE IS LMTD SO KEPT FCST DRY ATTM. HIGH PRES BLDS IN
SAT NGT THRU MON NGT UNTIL A CDFNT APRCHS FM THE W ON TUE WITH
ANOTHER CHC FOR SHRA/TS. TEMPS SHOULD BE BLO AVG LVLS OVR THE
WKEND...WITH A WRMG TREND ERLY NXT WK.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING. THINK THAT A
BRIEF PERIOD OF TSRA REMAINS POSSIBLE WITH THE FRONT AS IT PASSES.
GUSTY SW WNDS LATE THIS AFTN SHOULD SHFT TO THE W AND THEN N THIS
EVE AFT FROPA. MVFR CIGS WILL REMAIN A POSSIBILITY AT FKL/DUJ INTO
THE EVE...OTRW GENL LOW END VFR CIGS FCST OUTSIDE OF ANY PCPN ACRS
THE RGN.
.OUTLOOK.../WEDNESDAY NIGHT THROUGH SUNDAY/...
THE FNT WL MOVE BACK N AS A WRMFNT WED NGT INTO THU WITH BRF RESTRNS
PSBL. A CDFNT WL MOVE E ACRS THE RGN FRI WITH SHRA/TS RESTRNS BEFORE
HI PRES BLDS IN SAT.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS WAKEFIELD VA
211 PM EDT TUE APR 16 2013
.SYNOPSIS...
A WEAK FRONTAL BOUNDARY WILL CROSS JUST NORTH OF THE REGION
TONIGHT. OTHERWISE...HIGH PRESSURE BECOMES CENTERED OFF THE MID
ATLANTIC COAST FOR MOST OF THIS WEEK. A MORE VIGOROUS COLD FRONT
WILL IMPACT THE AREA FRIDAY INTO SATURDAY..
&&
.NEAR TERM /THROUGH TONIGHT/...
OVERALL CONDITIONS IMPROVE AS CLOUDY SKIES THIS MORNING BREAK UP
DURING THIS AFTN AND TEMPS WARM TOWARD 70-75 DEGREES AREAWIDE...EXCEPT AT
THE BEACHES WHERE TEMPS WILL BE IN THE 60S DUE TO PERSISTENT
ONSHORE FLOW. THE LOCAL WRF AND THE RAP MODELS ALL SHOW THE
MOISTURE SLOW TO MIX OUT IN THE WEST IN THE 925 TO 850 MB LAYER.
THEY DO SHOW THAT LEVEL WINDS SLOWLY MOVING TO SOUTHWEST AND
DRYING DEVELOPING. WILL ALSO KEEP TEMPERATURES COOLER IN THE WEST
INITIALLY WITH MORE CLOUD COVER. FOR TONIGHT...A COLD FRONT
PASSES ACROSS NEW ENGLAND AND WILL DRAG A WEAK BOUNDARY ACROSS
NWRN PORTIONS OF THE FA OVERNIGHT. THIS FEATURE WILL BRING
INCREASED CLOUDS TO THIS AREA WITH PARTLY CLOUDY SKIES FARTHER TO
THE SE. LOW TEMPS WILL RUN ABOUT 5 DEGREES ABOVE NORMAL AS CLOUD
COVER INSULATES THE ATMOSPHERE TONIGHT. EXPECT LOWS IN THE MID TO
UPPER 50S REGIONWIDE (LOW TO MID 50S IMMEDIATE COAST).
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
WED/WED NIGHT...RELATIVELY FLAT UPPER LEVEL RIDGING AND SW FLOW
OVER THE TN VALLEY AND SPINE OF THE APPALACHIANS WILL ALLOW
MOISTURE AND WEAK SHORTWAVE ENERGY TO MOVE AROUND THE PERIPHERY OF
THE UPPER RIDGE DURING THE AFTN/EVENING. THE DEVELOPMENT OF A LEE
TROUGH IS ALSO POSSIBLE AS THE FRONT FROM TUE NIGHT STALLS ACROSS
SE VA/NE NC. UNLIKE MOST LEE TROUGHS THAT TEND TO DEVELOP OVER THE
ERN PIEDMONT...THIS ONE IS EXPECTED TO TAKE ON MORE OF A
POSITIVELY TILTED ORIENTATION (ENE TO WSW). INCREASING TEMPS AND
DEWPOINTS DURING THE DAY WILL CREATE ENOUGH LOW-LEVEL INSTABILITY
FOR LIGHT SHOWERS TO BE POSSIBLE NORTH OF THE TROUGH AXIS.
HOWEVER...WEAK DYNAMICS AND VERY LIGHT WINDS BELOW 500 MB WILL
LIMIT THUNDER POTENTIAL TO A SLIGHT CHANCE IN THE AFTN/EVENING.
EXPECT A NICE WARM-UP WITH HIGHS IN THE LOWER 80S FOR MOST
AREAS...IN THE MID-UPPER 70S FOR THE IMMEDIATE COAST...AND IN THE
UPPER 60S NEAR OCEAN CITY MD. ANY SHOWERS THAT DEVELOP SHOULD
DISSIPATE QUICKLY AROUND SUNSET DUE TO THE LOSS OF DAYTIME HEATING
AND BECAUSE OF THE WEAK DYNAMICS ALREADY PRESENT. MOSTLY CLOUDY
SKIES WILL ONCE AGAIN HAMPER LOW TEMPS FROM DROPPING TO THEIR FULL
POTENTIAL. LOWS SHOULD GENERALLY BE AROUND 60 (MID-UPPER 50S
IMMEDIATE COAST).
THU/THU NIGHT...THE MID AND UPPER LEVEL RIDGE AXES MOVE OFFSHORE ON
THU. SW FLOW ALOFT WILL RESULT IN WAA TAKING PLACE THUS ALLOWING
HIGH TEMPS TO WARM A FEW MORE DEGREES AS COMPARED TO WED. AN
APPROACHING COLD FRONT MOVING ACROSS THE CTRL U.S. WILL CAUSE THE
SFC PRESSURE GRADIENT TO TIGHTEN...THEREFORE GUSTS OF 20-25 MPH ARE
ANTICIPATED DURING THE AFTN. ASIDE FROM BREEZY CONDITIONS...THU
WILL BE A RATHER NICE DAY ACROSS THE AREA. THE VIGOROUS COLD FRONT
CONTINUES TO DIG INTO THE MIDWEST THU NIGHT...ACTING TO SLOW ITS
EWD PROGRESSION INTO THE MID ATLANTIC REGION. SFC WINDS WILL
BECOME MORE SLY THU NIGHT AND REINFORCE ONGOING WAA PROCESSES. THE
COMBINATION OF WAA AND INCREASING HIGH CLOUDS FROM THE APPROACHING
SYSTEM WILL ALLOW LOW TEMPS TO RUN ABOUT 10-15 DEGREES ABOVE
SEASONAL NORMALS. LOWS SHOULD GENERALLY BE IN THE LOWER 60S (55 TO
60 IMMEDIATE COAST).
FRI...THE APPROACHING (AND VIGOROUS) COLD FRONT WILL CONTINUE TO
APPROACH THE MID ATLANTIC REGION ON FRI. SLY SFC WINDS WILL INCREASE
FURTHER WITH GUSTS OF 25-30 MPH LIKELY AS THE PRESSURE GRADIENT
TIGHTENS EVEN MORE. THERE ARE SOME INDICATIONS THAT PRECIPITATION
GENERATION MAY NOT OCCUR UNTIL FRI AFTN...BUT HAVE KEPT THE
MORNING FORECAST INTACT FOR NOW WITH CHC SHOWERS FOR THE ERN
PIEDMONT AND SCHC SHOWERS AS FAR AS THE MID ATLANTIC COAST. FOR
THE AFTN...LEE TROUGH DEVELOPMENT IS ANTICIPATED DUE TO
TEMPERATURE DIFFERENCES AHEAD OF AND BEHIND THE FRONT. ALSO...
ISENTROPIC SFCS INDICATE 40-50 KT OF SW FLOW WITH THE BEST
MOISTURE IN THE PIEDMONT DURING THE AFTN. DUE TO THE SLOWER NATURE
OF DIGGING SYSTEMS...THE FRONT SHOULD BE DELAYED AND BEST PRECIP
CHANCES SHOULD OCCUR IN THE PIEDMONT THU AFTN ALONG THE LEE TROUGH
AXIS WITH MORE SHOWERS DEVELOPING FARTHER EAST DURING THE EVENING.
FAVORABLE THERMAL PROFILES AND UNIDIRECTIONAL WIND SHEAR...IN
ADDITION TO DYNAMIC SUPPORT ALOFT...WILL SUPPORT THUNDERSTORMS
WITH THE POTENTIAL FOR DAMAGING WIND GUSTS ON FRI AFTN INTO FRI
NIGHT. PWATS ARE ALSO PROGGED TO REACH 1.50 INCHES WHICH WILL
RESULT IN MODERATE TO HEAVY RAINFALL. THIS SYSTEM BEARS CLOSE
MONITORING SINCE IT IS TOO EARLY TO NARROW DOWN THE FINER DETAILS.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
WILL INCREASE POPS QUICKLY FROM WEST TO EAST BY FRIDAY EVENING
INTO SATURDAY MORNING AS THE FRONT MOVES THROUGH. EXPECTING
THE PRECIP TO END ACROSS THE LOCAL AREA SATURDAY AFTERNOON. LOWS
FRIDAY NIGHT MAINLY IN THE 50S. COOLER SATURDAY WITH HIGHS IN THE
60S. HIGH PRESSURE BRIEFLY BUILDS IN SUNDAY FOR DRY WX. THERE IS
THE POSSIBILITY OF INCREASED ONSHORE FLOW NEXT MONDAY WITH A
COASTAL FRONT/INVERTED TROUGH BACKING INTO THE AREA. WILL
ADVERTISE SOME LOW POPS BY NEXT MONDAY FOR NOW AND KEEPS HIGH
TEMPS IN THE 60S NEXT SUNDAY/MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
TAF SITES WILL HAVE BKN/OVC CIGS 4 TO 7K FT AGL WITH SOME
POTENTIAL LOWERING TO MVFR LEVELS (3K FT AGL) IN WESTERN PORTIONS
OF THE CWA. HIGH PRESSURE MOVES BACK INTO THE REGION WITH LOW LEVEL
MOISTURE BRINGING A CHANCE FOR PATCHY FOG/LOW CIGS BY EARLY WED
MORNING. ISOLATED TO WIDELY SCATTERED SHRA/TSRA WILL BE POSSIBLE
WED LATE AFTN/EARLY EVENING (GREATEST CHC FOR THIS AT KRIC).
COULD AGAIN SEE SOME PATCHY FOG/LOW CLOUDS EARLY THU.
OTHERWISE...MAINLY VFR UNTIL THE FRONT ARRIVES FRI AFTN INTO EARLY
SAT...BRINGING NUMEROUS SHRA/ISOLATED TO SCATTERED TSRA AND A
PERIOD OF IFR CONDITIONS.
&&
.MARINE...
HAVE ADDED A FEW MORE ZONES INTO THE SCA HEADLINES...AS SEAS REMAIN
6-8 FT ACRS SE VA AND NE NC COASTAL WATERS (3-4 FT AT THE MOUTH OF
THE BAY)...AND ARE SLOWLY INCREASING FARTHER NORTH. FOR COASTAL
WATERS N OF PARRAMORE WILL START THE SCA BY 7 AM...AND SEAS SHOULD
AVG 4-6 FT ACRS THESE AREAS THROUGH THE EVENING. WHILE MUCH OF THIS
IS DUE TO SWELL RATHER THAN WIND HAVE DECIDED TO KEEP IT SMALL CRAFT
ADVSY AS OPPOSED TO SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS TO AVOID
CONFUSION W/ MULTIPLE HEADLINES.
OTHERWISE...WEAK LOW PRESSURE IS STILL SITUATED OFF THE SC COAST
WITH HIGH PRESSURE CENTERED OFF THE NEW ENGLAND COAST AND THE
RESULTANT FLOW BETWEEN THESE TWO FEATURES CONTINUES TO PRODUCE E/SE
WINDS. WIND SPEEDS TODAY ARE NOT EXPECTED TO GET MUCH ABOVE 15 KT SO
DO NOT ANTICIPATE ANY HEADLINES OUTSIDE OF THE COASTAL WATERS AND
MOUTH OF THE BAY FOR TODAY. IT MAY BE CLOSE IN THE BAY BY THIS
EVENING AS SE FLOW INCREASES SOMEWHAT AS IT OFTEN DOES IN THE
EVENING (WHILE THEY WEAKEN OVER LAND). FOR NOW HAVE KEPT THEM CAPPED
AT 15 KT. WINDS WILL THEN TURN MORE TO SW OVERNIGHT BEFORE BECOMING
RATHER LIGHT ON WED. THIS SHOULD ALLOW SEAS TO SUBSIDE BELOW 5 FT.
WINDS INCREASE ON THU...AND ESPECIALLY THU NIGHT THROUGH FRI AS
PRESSURE GRADIENT TIGHTENS UP AHEAD OF THE APPROACHING COLD FRONT.
SCA CONDITIONS ARE LIKELY THU NIGHT THROUGH FRI NIGHT.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR ANZ634-
654-656-658.
SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ650-
652.
&&
$$
SYNOPSIS...BMD
NEAR TERM...BMD/JAB
SHORT TERM...BMD
LONG TERM...JDM
AVIATION...LKB/DAP
MARINE...LKB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
437 PM EDT TUE APR 16 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL TROUGH FROM
NRN QUEBEC THROUGH JAMES BAY INTO NRN ONTARIO WAS DEPARTING TO THE
EAST. UPSTREAM...SW FLOW PREVAILED THROUGH THE PLAINS AHEAD OF A
TROUGH FROM THE NRN ROCKIES THROUGH THE GREAT BASIN. WITH CONFLUENT
FLOW WITH QVECTOR DIV AND SUBSIDENCE OVER THE NRN GREAT LAKES...THE
SCT FLURRIES HAD DIMINISHED THIS AFTERNOON.
AS HIGH PRES BUILDS INTO NRN ONTARIO TONIGHT BRINGING ENE ACYC FLOW
INTO UPPER MI AND DAYTIME HEATING FADES...EXPECT THAT WINDS WILL
DIMINISH AND CLOUDS WILL THIN OUT ENOUGH FOR TEMPS TO DROP INTO THE
20S.
AS THE WRN TROUGH EDGES TO THE EAST AND A SFC-850 MB TROUGH DEVELOPS
FROM THE SRN PLAINS INTO THE UPPER MS VALLEY...WAA AND MOISTURE
ADVECTION WILL INCREASE QUICKLY BY WED AFTERNOON. THE INITIAL AREA
OF PCPN IS EXPECTED INTO THE WEST...WHERE 295K-300K ISENTROPIC LIFT
IS STRONGEST. GIVEN THE DRY ERLY FLOW AS THE HIGH GRADUALLY MOVES
EAST THROUGH NRN ONTARIO...THE SLOWER PROGRESSION OF PCPN INTO
UPPER...PER NAM...WAS PREFERRED COMPARED TO THE GFS/ECMWF. EXPECT
ENOUGH OF A LINGERING WARM LOWER LAYER FOR MOSTLY RAIN AT THE ONSET
OF MAINLY LIGHT PCPN AS AFTERNOON TEMPS CLIMB INTO THE 40F TO 45F
RANGE.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 436 PM EDT TUE APR 16 2013
MAIN ATTENTION FOR THE LONG TERM PORTION OF THE FORECAST ARE THE
TWO WAVES OF PRECIPITATION ASSOCIATED WITH ENERGY AND LOW PRESSURE
SYSTEMS EXITING FROM THE UPPER TROUGH CURRENTLY MOVING THROUGH THE
WESTERN CONUS.
FIRST WAVE WILL BE INFLUENCING THE AREA AT THE START OF THE LONG
TERM PERIOD WILL BE ASSOCIATED WITH SHORTWAVE ENERGY EJECTING AHEAD
OF THE TROUGH EXPECTED TO BE IN THE CENTRAL ROCKIES. AT THE
SURFACE...A LOW CENTERED IN WESTERN OKLAHOMA AND THE
PANHANDLE OF TEXAS WILL BEGIN ELONGATING A TROUGH NORTHEAST INT HE
MID MISSISSIPPI VALLEY ON WEDNESDAY AFTERNOON AND THEN NORTHEAST
INTO NORTHERN LAKE MICHIGAN BY 12Z THURSDAY. WITH THE STRONG MID
LEVEL FORCING ASSOCIATED WITH 925-700MB WARM AIR ADVECTION AND
LIKELY CONVECTION ON THE EAST SIDE OF THE TROUGH...WOULD EXPECT THE
HEAVIEST PRECIPITATION TO BE JUST TO THE SOUTHEAST OF THE CWA OR
BRUSH THE SOUTHEAST PART OF THE CWA. BUT...WITH THE AREA UNDER THE
RIGHT REAR OF THE UPPER JET AND ENOUGH OVERRIDING FLOW WITH THAT
WARM AIR ADVECTION AND ISENTROPIC ASCENT ON THE 280-300K
SFCS...STILL THINK THAT THERE WILL BE ENOUGH FORCING FOR MODERATE
PRECIPITATION ACROSS MUCH OF THE CWA. GENERAL MODEL CONSENSUS OF
0.50-0.80 INCH SEEMS REASONABLE FOR MUCH OF THE AREA...WITH VALUES
APPROACHING AN INCH ALONG THE LAKE MICHIGAN SHORELINE. THIS TRICKY
PART OF THIS FORECAST IS WHAT AMOUNT OF THE PRECIP WILL FALL AS
RAIN OVER THE WESTERN HALF OF THE CWA DUE TO THE ELEVATED WARM
LAYER. THERE CONTINUES TO BE SOME DISCREPANCY IN THE AMOUNT OF WARM
AIR THAT MOVES OVER THE CENTRAL CWA AND HOW FAR WEST THAT MOVES.
THINK THE FAR WESTERN CWA WILL LIKELY SEE MAINLY SNOW /FROM
KCMX TO KIWD/...BUT COULD SEE A BRIEF PERIOD OF FREEZING RAIN
OVERNIGHT. THE AREA BETWEEN THERE AND A LINE FROM MARQUETTE TO IRON
MOUNTAIN IS THE TRICKY AREA...SINCE THERE WILL LIKELY BE ENOUGH
WARM AIR TO MELT THE SNOW ALOFT. THEN PRECIP TYPE COMES DOWN TO
SURFACE TEMPERATURES...SINCE 925MB TEMPS ARE WELL BELOW FREEZING.
WILL CONTINUE TO MENTION MAINLY FREEZING RAIN IN THAT AREA...WITH
SOME MENTION OF SNOW. ALL IN ALL...APPEARS THAT THIS WILL LIKELY BE
A SOLID ADVISORY FOR THE WESTERN HALF OF THE CWA AND THERE IS SOME
CONCERN FOR DECENT ICE ACCUMULATION DEPENDING ON WHAT THE SURFACE
TEMPS ARE. THIS ENERGY WILL SHIFT NORTHEAST ON THURSDAY MORNING AND
WITH THE 850MB FLOW BECOMING MORE SOUTHWEST...WOULD EXPECT THE
PRECIPITATION TO WEAKEN HEADING INTO THE AFTERNOON.
NEXT SYSTEM TO AFFECT THE AREA WILL BE AS THE UPPER TROUGH LIFTS TO
THE NORTHEAST AND MOVES TOWARDS THE UPPER GREAT LAKES ON THURSDAY
NIGHT INTO FRIDAY. THIS WILL INTENSIFY A LOW ALONG THE LINGERING
SURFACE TROUGH AND THEN LIKELY TRACK TOWARDS THE STRAITS OF
MACKINAC BY 12Z FRIDAY. THE MAIN CONCERN FOR WIDESPREAD
PRECIPITATION FOR THE AREA IS THE TRACK/LOCATION OF THE DRY SLOT
SURGING NORTHEAST ON THURSDAY NIGHT INTO FRIDAY. THERE ARE STILL
SOME DIFFERENCES IN THE LOW TRACK WITH THE NAM/GEM...SO OPTED TO
FOLLOW THE MORE CONSISTENT IDEA OF THE GFS/ECMWF FOR THE FORECAST.
LATEST INDICATIONS IN THE MODELS THAT THE DRY SLOT WILL AFFECT THE
CENTRAL/EASTERN CWA...BETWEEN THE DEFORMATION PRECIPITATION
AFFECTING THE WESTERN CWA AND THE CONVECTION AND HEAVY RAIN
AFFECTING LOWER MICHIGAN AHEAD OF THE COLD FRONT. THUS...WOULD
EXPECT THE HEAVIEST PRECIPITATION TO OCCUR OVER THE WESTERN THIRD OF
THE CWA THURSDAY NIGHT INTO FRIDAY...WITH THE REST OF THE AREA
SEEING LIGHTER PRECIPITATION. BASED OFF THE THERMAL PROFILE...THAT
ALSO SEEMS TO BE THE LOCATION OF THE RAIN/SNOW/MIXED PRECIPITATION
LINE...LARGELY STRETCHING FROM KIMT/KSAW. THE CONCERN FOR THE
CENTRAL CWA WILL BE THE EXPECTED AREA OF SUBFREEZING TEMPERATURES
BELOW 875MB WHICH WOULD LEAD TO THE RAIN FREEZING WHEN IT GETS TO
THE SURFACE. OUT WEST...THE PRECIPITATION WILL LIKELY START OUT AS
FREEZING RAIN AS THE WARM NOSE ROTATES THROUGH AND THEN TRANSITION
TO SNOW FROM WEST TO EAST. WHEN COMBINED WITH THE NORTHERLY FLOW OFF
LAKE SUPERIOR WITH 850MB TEMPS FALLING TO -10C ON FRIDAY SHOULD SEE
LAKE ENHANCEMENT REALLY INCREASE AMOUNTS OVER GOGEBIC/ONTONAGON
COUNTIES THROUGH THE DAY ON FRIDAY. WITH THAT AREA SEEING BOTH THE
DEFORMATION PRECIPITATION AND THE LAKE ENHANCEMENT...CURRENT
EXPECTATION WOULD BE WARNING SNOWFALL AMOUNTS AND SOME LOCATIONS
COULD SEE SOME SIGNIFICANT SNOWFALL AMOUNTS FOR MID-LATE APRIL. IN
ADDITION TO THE SNOW...STRONG NORTHERLY WINDS FROM THE KEWEENAW
THROUGH GOGEBIC COUNTY WILL LEAD TO NEAR BLIZZARD CONDITIONS EVEN
THOUGH THE SNOW WILL LIKELY BE ON THE WETTER SIDE INITIALLY.
WILL CONTINUE THE SPS FOR THE WEDNESDAY NIGHT THROUGH FRIDAY
PERIOD...SINCE I FEEL THAT ENCOMPASSES THE ENTIRE SYSTEM WELL AND
SINCE THE THE MOST SIGNIFICANT EVENT WILL BE THE SECOND SYSTEM.
COULD HAVE DONE A LONG PERIOD WATCH TO COVER BOTH EVENTS...BUT SINCE
THE FIRST WAVE SEEMS TO BE MORE OF AN ADVISORY SITUATION AND THEN A
BRIEF BREAK ON THURSDAY AFTERNOON...WASN`T SURE IF THAT WOULD COME
ACROSS WELL WITH A LONG TERM WATCH HEADLINE.
EXPECT THE LAKE ENHANCED SNOW TO CONTINUE INTO FRIDAY NIGHT BUT
WILL QUICKLY COME TO AN END ON SATURDAY AS THE UPPER TROUGH LIFTS
TO THE NORTHEAST AND SURFACE HIGH PRESSURE BUILDS OVER THE AREA.
THIS SHOULD LEAD TO A NICE BUT COOL START TO THE WEEKEND...WITH
HIGHS ONLY REACHING THE 30S IN MOST LOCATIONS. THEN AS THE HIGH AND
UPPER RIDGE SHIFTS TO THE EAST ON SUNDAY...THE NEXT WAVE FROM THE
PACIFIC NORTHWEST WILL BE APPROACHING THE AREA FOR SUNDAY NIGHT AND
CONTINUING INTO MONDAY NIGHT AND TUESDAY. THERE CONTINUES TO BE
SOME DIFFERENCES IN THE DETERMINISTIC MODELS AND THERE ENSEMBLE
MEANS...BUT THE GENERAL IDEA OF THE UPPER TROUGH AND COLD FRONT
MOVING THROUGH THE AREA DURING THAT TIME SEEMS REASONABLE. THE AREA
WILL LIKELY SEE A BRIEF WARM UP FOR SUNDAY INTO MONDAY...BACK INTO
THE 40S...BUT THEN COOL TO BELOW NORMAL VALUES BEHIND THE COLD FRONT
ON TUESDAY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 131 PM EDT TUE APR 16 2013
ABUNDANT 925-850 MB MOISTURE ALONG WITH DAYTIME HEATING SUPPORTED
BKN CIGS JUST ABOVE 3K FT AT IWD/SAW AND AROUND 2K FT AT CMX. EXPECT
MVFR CIGS WILL LIFT/SCATTER OUT TOWARD EVENING WITH CONTINUED MIXING
AND SLIGHTLY DRIER AIR MOVING IN. VFR CONDITIONS ARE EXPECTED
TONIGHT. ALTHOUGH THERE IS UNCERTAINTY WITH THE AMOUNT OF 925-900 MB
MOISTURE ACROSS NORTHERN UPPER MI WED MORNING...PER NAM/GFS...A
MENTION OF MVFR CIGS WAS INCLUDED.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 436 PM EDT TUE APR 16 2013
WINDS WILL STAY BELOW 30 KNOTS THROUGH THU BEFORE INCREASING OUT OF
THE NORTH THURSDAY NIGHT INTO FRIDAY NIGHT WHEN NORTH GALES ARE
LIKELY AS A DEEP LOW PRESSURE SYSTEM MOVES TOWARD NORTHERN LAKE
MICHIGAN AND EAST UPPER MICHIGAN. THERE IS THE POTENTIAL FOR HIGHER
END GALES WITH THIS SYSTEM IN THE 40 TO 45 KNOT RANGE. THE WINDS
WILL DIMINISH FRI NIGHT INTO SAT AS THE LOW MOVES QUICKLY TO THE
NORTHEAST OF THE REGION AND HIGH PRES BUILDS IN FROM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
219 PM EDT TUE APR 16 2013
.AVIATION...
//DISCUSSION...
THE FRONTAL BOUNDARY HAS SLIPPED SOUTHEAST OF THE AREA ACROSS FAR
EASTERN PORTIONS OF LAKE ERIE AND OHIO. BUILDING SURFACE HIGH
PRESSURE SOUTH OF HUDSON BAY REGION TONIGHT WILL ALLOW
ANTICYCLONIC FLOW TO BUILD SOUTHWARD INTO THE GREAT LAKES. THIS
SHOULD RESULT IN AN EVENING INLAND RELEASE OF THE LAKE/MARINE
AIRMASS...SUBSEQUENTLY DRYING OUT THE NEAR SURFACE ENVIRONMENT.
MEANWHILE...A SAMPLE OF THE HI RESOLUTION MODELS ARE SUGGESTING
SOME NORTHERN FRINGE SHOWERS AND MIDLEVEL MOISTURE WILL LIFT/CLIP
INTO THE SOUTHERN TAF SITES AFTER 21Z...PERSISTING INTO THE
EVENING. THIS IS A LOW CONFIDENCE FORECAST AS THOSE SOLUTIONS ARE
EXHIBITING SOME CONVECTIVE START UP ISSUES. WILL MONITOR AND AMEND
THE TAFS MORE PESSIMISTIC AS NEEDED.
//DTW THRESHOLD THREATS...
* LOW CONFIDENCE IN LIGHT PRECIPITATION POTENTIAL THIS EVENING.
* HIGH CONFIDENCE CEILINGS WILL FALL BELOW 5000FT AFTER 10Z
WEDNESDAY.
&&
.PREV DISCUSSION...ISSUED 613 AM EDT TUE APR 16 2013
UPDATE...
LOW LEVEL FGEN...NOT PICKED UP BY THE 00Z MODELS...WAS PICKED UP
BY THE 06Z MODELS AND CENTERED AROUND H9. DESPITE PICKING THIS LOW
LEVEL FGEN UP THE NWP MODELS CONTINUE TO UNDERESTIMATE THE CURRENT
ACTIVITY ABOUT TO SWEEP THROUGH EXTREME SOUTHEASTERN MICHIGAN.
HOWEVER THE RECENT 3KM HRRR MODEL PICKS THIS UP NICELY AND SWEEPS
THE MODERATE SHOWERS THROUGH THE AREA BETWEEN 10-13Z THIS MORNING.
WITH MODEST INSTABILITY AND INTERSPERSED LIGHTNING STRIKES WILL
ADD THUNDER TO THE MUCH RAISED POPS ACROSS THE SOUTHERN CWA THIS
MORNING AS THE COLD FRONT CONTINUES MARCHING SOUTHEASTWARD. AT
THIS TIME THE REST OF THE FORECAST LOOKS FINE GOING FORWARD AS THE
ACTIVITY TO THE NORTH HAS SIGNIFICANTLY DECREASED AS ADVERTISED.
PREV DISCUSSION...ISSUED 334 AM EDT TUE APR 16 2013
SHORT TERM...THIS MORNING THROUGH TONIGHT
AN AREA OF SHOWERS STRETCHING FROM CENTRAL LAKE HURON BACK TO
SOUTHERN LAKE MICHIGAN ALONG A SLOWLY MOVING COLD FRONT AND
COINCIDENT WITH FGEN IN THE H9-H7 LAYER WILL SLOWLY MOVE SOUTHEAST
DURING THE MORNING HOURS. HOWEVER MODEL CROSS SECTIONS SHOW THE FGEN
WILL ELONGATE...WEAKEN AND LIFT NORTH AS THE MORNING WEARS ON. DEEP
MOISTURE ASSOCIATED WITH THE FRONT WILL LIFT NORTH WITH THE MAIN
FGEN BAND...AS THE FRONT ITSELF BECOMES DIFFUSE TEMPERATURE-WISE.
THESE FACTORS DO NOT LEAD TO A HIGH DEGREE OF CONFIDENCE THAT RAIN
SHOWERS WILL ACTUALLY MAKE IT ALL THE WAY THROUGH THE SOUTHERN AND
EASTERN CWA THIS MORNING AS THE FRONT TRACKS TOWARDS THE NORTHERN
OHIO VALLEY. GIVEN THE WEAKENING DYNAMICS AND DECREASED AVAILABLE
MOISTURE WILL NOT DRAG THE CATEGORICAL POPS ALL THE THROUGH THE
SOUTHEASTERN CWA THIS MORNING AS THE FRONT MOVES SOUTH...AND INSTEAD
LEAVE LIKELY POPS ACROSS THESE AREAS PER THE PREVIOUS FORECAST. WITH
THE FRONT OVER THE NORTHERN OHIO VALLEY POPS WILL BE RATHER LOW THIS
AFTERNOON AND THIS EVENING AS THE MAIN DYNAMICS STAY TO THE SOUTH.
WITH A BETTER HANDLE ON THE PLACEMENT OF THE FRONT WILL TAKE THE
CHANCY POPS FROM THE AFTERNOON AND PLACE THEM IN THE EVENING HOURS
AS THE SURGE NORTHWARD OF THE MID-LEVEL FRONT AND INCREASED FGEN
OVER THE SOUTHERN GREAT LAKES DOES NOT MAKE IT INTO THE SOUTHEASTERN
MICHIGAN UNTIL LATER TONIGHT. THEREFORE WILL REFINE THE WINDOW FOR
LIKELY POPS TO AFTER MIDNIGHT WHEN THIS BETTER FORCING COMES BACK
INTO THE CWA. WITH MEAGER DYNAMICS AND NOT MUCH INSTABILITY TO SPEAK
OF WILL CONTINUE TO LEAVE THUNDER OUT OF THE FORECAST THROUGH
TONIGHT.
WITH THE PUSH OF COLD AIR BEHIND THE COLD FRONT BECOMING MORE
DIFFUSE...HIGH TEMPERATURES TODAY SHOULD BE ABLE TO GET INTO THE
UPPER 50S TO LOWER 60S. NORTHEAST WINDS OVERNIGHT WILL BRING COOLER
AIR IN FROM THE GREAT LAKES...WITH LOWS RANGING FROM THE MID 30S
ACROSS THE NORTH TO THE LOW TO MID 40S ACROSS THE SOUTH.
LONG TERM...
HIGHLY AMPLIFIED PATTERN DEVELOPING...AS UPPER LEVEL ENERGY OVER
PACIFIC NORTHWEST EXTENDING SOUTH INTO THE GREAT BASIN CONTINUES TO
CONSOLIDATE AND ORGANIZE. THE 00Z MODEL TRENDS ARE DEEPER WITH THE
SYSTEM COMING OUT OF THE CENTRAL CONUS/MIDWEST THURSDAY...AND IT NOW
APPEARS FRIDAY MORNING WILL BE MILD AND RAINY BEFORE THE STRONG LOW
LEVEL COLD ADVECTION SENDS 850 MB TEMPS BELOW ZERO BY 00Z SATURDAY.
THURSDAY/THURSDAY NIGHT LOOKS VERY WET ...AS IMPRESSIVE LOW LEVEL
JET (50 TO 55 KNOTS AT 850 MB) EXTENDS FROM TEXAS ALL THE WAY UP TO
THE CENTRAL GREAT LAKES...ALLOWING COPIOUS AMOUNTS OF GULF OF MEXICO
MOISTURE TO STREAM NORTHWARD. STILL HAVE SOME CONCERN FOR SEVERE
WEATHER ON THURSDAY WITH THE IMPRESSIVE WIND FIELDS...AS 00Z GFS
EVEN ADVERTISING SURFACE BASED CAPES IN SOLIDLY EXCESS OF 1000 J/KG
THERE IS A STRONG POSSIBILITY A FLOOD WATCH WILL BE NEEDED FOR
THURSDAY-FRIDAY MORNING TIME FRAME AS THIS DYNAMIC SYSTEM AND
MOISTURE LADEN (PW VALUES TO AROUND 1.5 INCHES) IMPACTS THE GREAT
LAKES REGION. THE FORECAST IS COMPLICATED ON THURSDAY DUE TO THE
FACT RIGHT ENTRANCE REGION FORCING OF THE UPPER LEVEL JET IS
DISPLACED WELL TO THE NORTH OF LOWER MICHIGAN...SO NOT A GUARANTEE
IS GOING TO RAIN ACROSS THE FAR SOUTHEAST AS WE REMAIN UNDER THE
INFLUENCE OF THE DEPARTING UPPER LEVEL RIDGE. ON THE FLIP SIDE...IF
THE ALL BLEND SURFACE DEW PTS OF 62-63 DEGREES VERIFY...THAT IS
CLIMATOLOGY NEAR RECORD TERRITORY...AND HARD TO BELIEVE THE ENHANCED
ISENTROPIC ASSENT WILL NOT GENERATE SHOWERS AND THUNDERSTORMS WITH
THE MORE THAN ADEQUATE INSTABILITY.
NEED TO MENTION THE POTENTIAL FOR STRONG WIND POP RIGHT BEHIND THE
POWERFUL COLD FRONT ON FRIDAY...AS 6 HR RISE/FALL PRESSURE COUPLET
IS INTENSIFYING THROUGH THE DAY...AND LOOKS TO BE AT LEAST 20 MB.
WITH THE STOUT LOW LEVEL COLD ADVECTION/SUBSIDENCE COMING THROUGH
DURING THE PEAK HEATING OF THE DAY...MIXING INTO THE 45 TO 50 KNOT
WINDS AT 850 MB DOES NOT LOOK TO BE MUCH OF A CHALLENGE...AND WILL
HIGHLIGHT THE POTENTIAL OF WIND GUSTS OF 45 MPH OR GREATER IN HWO.
QUIET BY COOL WEATHER FOR THE WEEKEND...AS 850 MB TEMPS STILL
PROGGED TO BE RUNNING AROUND -10 C TO START THE DAY ON
SATURDAY...BUT MODIFYING INTO THE MID SINGLE NUMBERS DURING THE
AFTERNOON...AND NEGATIVE LOW SINGLE NUMBERS FOR SUNDAY
AFTERNOON...PER 00Z EURO.
MARINE...
A SLOWLY MOVING COLD FRONT WILL FLIP THE WIND DIRECTION TO WNW
ACROSS ALL OF THE CENTRAL GREAT LAKES REGION THIS MORNING. WINDS
WILL THEN VEER TO THE NORTHEAST TONIGHT THEN TO AN EASTERLY
DIRECTION ON WEDNESDAY. HOWEVER SHORT DURATION FETCH AND A LACK OF
STRONGER WINDS WILL LIMIT SIGNIFICANT WAVE HEIGHTS TO 5 FEET OR LESS
ACROSS AREA WATERS THROUGH WEDNESDAY. PERSISTENT EASTERLY FLOW WILL
LEAD TO A BUILD UP OF WAVES ACROSS THE CENTRAL GREAT LAKES WEDNESDAY
NIGHT...WITH SMALL CRAFT HEADLINES A POSSIBILITY FOR ALL NEARSHORE
AREAS SAVE FOR INNER SAGINAW BAY. WILL ISSUE APPROPRIATE HEADLINES
AS NECESSARY AS THE EVENT DRAWS CLOSER.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....CB
UPDATE.......KURIMSKI
SHORT TERM...KURIMSKI
LONG TERM....SF
MARINE.......KURIMSKI
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
654 PM EDT TUE APR 16 2013
.SYNOPSIS...
A COLD FRONT WILL MOVE ACROSS THE REGION THIS EVENING ACCOMPANIED
BY RAIN SHOWERS. A RIDGE OF HIGH PRESSURE WILL BUILD SOUTH INTO
THE REGION FROM CANADA ON WEDNESDAY. A WARM FRONT WILL APPROACH
THE REGION ON THURSDAY. IT WILL WARM AND WINDY FRIDAY FOLLOWED BY
SHOWERS FRIDAY NIGHT AS ANOTHER COLD FRONT MOVES ACROSS THE NORTH
COUNTRY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
AS OF 654 PM EDT TUESDAY...PRE-FRONTAL RAIN SHOWERS HAVE EXITED
THE NORTH COUNTRY...THOUGH RECENT COMPOSITE RADAR SHOWS A FAIRLY
SOLID LINE OF RAIN SHOWERS APPROACHING THE SAINT LAWRENCE VALLEY
AND NORTHERN ADIRONDACKS OF NEW YORK. THESE SHOWERS ARE TIED TO
THE COLD FRONT AND HAVE GONE WITH AREAL COVERAGE WORDING TO HANDLE
THESE SHOWERS AS THEY MOVE ACROSS THE NORTH COUNTRY. RAP ANALYSES
SHOW A 85-95KT MID-LEVEL JET STREAK ORIENTED NORMAL TO THE SFC
BOUNDARY WHICH SUGGESTS THAT THE FRONT WILL BE QUICK TO MOVE EAST.
EXPECT THAT THESE SHOWERS WILL CONTINUE TO PROGRESS STEADILY
EASTWARD...CLEARING THE NORTH COUNTRY AROUND 05Z OR SO. THERE
COULD BE SOME BRIEF DOWNPOURS WITH THESE SHOWERS AS THEY MOVE
EAST...THOUGH QPF AMOUNTS SHOULD BE ON THE LIGHT SIDE. BEST
INSTABILITY REMAINS WELL SOUTH SO NOT EXPECTING ANY THUNDER WITH
THIS ACTIVITY.
A SHARP WIND SHIFT TO WEST/WEST-NORTHWEST IS EXPECTED WITH
CLEARING SKIES AND A NOTICEABLY DRIER AIRMASS FILTERING INTO THE
REGION. UNTIL THAT TIME...HAVE RAISED DEWPOINTS UP SEVERAL DEGREES
WITH DRYING OCCURRING WITH THE FRONT THEREAFTER. HAVE LEFT
TEMPERATURES LARGELY UNCHANGED AND WILL EVALUATE AS THE EVENING
PROGRESSES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 357 PM EDT TUESDAY...HIGH PRESSURE WILL BUILD INTO THE REGION
ON WEDNESDAY. CENTER OF THE HIGH REMAINS OVER THE JAMES BAY REGION
WITH SEASONABLY COOL NORTHERLY FLOW EXPECTED ACROSS THE NORTH
COUNTRY. THUS...TEMPERATURES WILL BE A LITTLE LOWER THAN ON TUESDAY
WITH HIGHS IN THE 50S. DRY WEATHER CONTINUES WEDNESDAY NIGHT
ALTHOUGH THERE WILL BE AN INCREASE IN CLOUDS WITH ONSET OF WARM AIR
ADVECTION AS HIGH PRESSURE MOVES FURTHER EAST AND RETURN SOUTHERLY
FLOW DEVELOPS BY THURSDAY MORNING. A WARM FRONT WILL APPROACH THE
REGION ON THURSDAY. HAVE GONE WITH CHANCE POPS FOR A FEW
SHOWERS...MAINLY OVER NORTHERN ZONES. DESPITE CLOUD
COVER...INCREASING SOUTHERLY FLOW WILL ALLOW FOR MILDER
TEMPS...WITH HIGHS WELL INTO THE 50S TO LOWER 60S. FURTHER
INCREASE IN SOUTHERLY FLOW THURSDAY NIGHT...SO EXPECT A MILD NIGHT
AND MAINLY DRY AS FORECAST AREA WILL BE IN WARM SECTOR.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 355 PM EDT TUESDAY...CONSISTENT FORECAST CONTINUES WITH
WARM MAX TEMPERATURES ON FRIDAY AS 850MB TEMPS INCREASE TO ABOUT
10C-12C. SOUTHERLY FLOW...WAA AND SOME BREAKS IN CLOUDS WILL WARM
SFC TEMPS INTO THE 60S AND L70S.
A COLD FRONT WILL APPROACH FROM THE WEST ON THE LATTER HALF OF
FRIDAY INTO FRIDAY NIGHT. THIS FRONT COULD TRIGGER SOME ISOLATED
TS...BUT PARAMETERS NOT QUITE LINING UP TIME-WISE. TEMP LAPSE
RATES OF 6+C/KM LOWERING AS AREA OF CAPE MOVES EASTWARD INTO NRN
NY. ALSO LIFTED INDICES STAYING ABOVE ZERO...SO HAVE NOT INCLUDED
TS IN FCST AT THIS TIME. WITH THIS SYSTEM...GEFS SHOWING PWATS
VALUES OF 2-3 STANDARD DEVIATIONS ABOVE NORMAL OVER THE NORTH
COUNTRY...WITH QPF AMOUNTS UP TO A HALF INCH THROUGH SATURDAY.
PRECIP AND COLD FRONT SHOULD EXIT ERN VT SOMETIME ON
SATURDAY...FOLLOWED BY HIGH PRESSURE BUILDING INTO THE GREAT
LAKES REGION. THIS RIDGE OF HIGH PRESSURE WILL CREST OVER THE
REGION SUNDAY NIGHT AND SLIDE EAST OVER NOVA SCOTIA ON MONDAY.
DRY CONDITIONS WILL LINGER INTO THE BEGINNING OF NEXT WEEK.
TEMPERATURES STARTING WARM WITH WAA AND SOUTHERLY FLOW AHEAD OF
THE COLD FRONT. A GENERAL COOLING TREND OVER THE WEEKEND BEHIND
THE FRONT. FRIDAY NT MIN TEMPS WILL BE IN THE 40S. SATURDAY AND
SUNDAY MAX TEMPS WILL BE IN THE 40S TO L50S. SATURDAY NT AND
SUNDAY NT EXPECT BELOW NORMAL MIN TEMPS IN THE L20S-L30S. TEMPS
WILL WARM SLIGHTLY AS THE HIGH PRESSURE CRESTS OVER THE REGION
AND WE GET A RETURN TO SOUTHERLY FLOW. MONDAY MAX TEMPS WILL
REACH THE M40S-U50S AND MIN TEMPS MONDAY NIGHT WILL BE IN THE
M20S-M30S.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...GUSTY SOUTHERLY WINDS WILL CONTINUE INTO
THIS EVENING AS LLJ REMAINS OVER THE NORTH COUNTRY. PRECIP HAS
MOVED OVER KMSS AND KSLK WITH MVFR CIGS AT KSLK. SO MAINLY VFR
CONDITIONS WILL SEE MVFR CIGS AND OCCASIONAL MVFR VSBYS IN RAIN
SHOWERS THIS AFTERNOON AND EARLY EVENING AS A COLD FRONT MOVES
EASTWARD THROUGH THE AREA. RAIN WILL GENERALLY BE LIGHT.
BEHIND THE FRONT...WINDS WILL SHIFT MORE WESTERLY AND WIND GUSTS
WILL TAPER DOWN TO 15-25 KTS. OVERNIGHT...MAINLY AFTER
06Z...SKIES WILL BEGIN TO CLEAR OUT AND GUSTS WILL FADE...LEAVING
NW WINDS AT 5-10 KTS.
APPROACHING WEDNESDAY MORNING...WINDS WILL PICK UP AT 8-12KTS OUT
OF THE NW WITH MAINLY CLEAR SKIES.
OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...
18Z WEDNESDAY THROUGH 12Z THURSDAY...VFR CONDITIONS EXPECTED AS A
RIDGE OF HIGH PRESSURE WILL BE OVER THE REGION.
12Z THURSDAY THROUGH 00Z FRIDAY...VFR/AREAS OF MVFR POSSIBLE AS A
WARM FRONT WILL BRING A CHANCE OF RAIN SHOWERS TO NY. VFR
EXPECTED OVER VT.
00Z FRIDAY THROUGH 00Z SATURDAY...MAINLY VFR CONDITIONS EXPECTED.
00Z SATURDAY THROUGH 00Z SUNDAY...VFR/MVFR CONDITIONS AS COLD
FRONT BRINGS RAIN ACROSS THE NORTH COUNTRY.
00Z SUNDAY ONWARD...VFR CONDITIONS AS HIGH PRESSURE BUILDS INTO
THE REGION.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...RJS
NEAR TERM...RJS/LOCONTO
SHORT TERM...RJS
LONG TERM...KGM
AVIATION...KGM
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
144 PM EDT TUE APR 16 2013
.SYNOPSIS...
SOUTHERLY WIND WILL CONTINUE TO BRING CLOUDS AND THEN INCREASING
CHANCES OF SHOWERS FROM THE WEST LATER THIS MORNING. A COLD FRONT
WILL MOVE ACROSS CENTRAL NEW YORK THIS AFTERNOON...AND INTO
NORTHEAST PENNSYLVANIA THIS EVENING WITH SHOWERS AND A SLIGHT
CHANCE OF THUNDERSTORMS. ANY STORMS THAT FORM MAY CONTAIN GUSTY
WINDS. SHOWERS WILL END OVERNIGHT...LEAVING WEDNESDAY DRY. WARMER
AIR WILL RETURN TO THE REGION FOR THURSDAY...FOLLOWED BY A STRONG
COLD FRONT FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
115 PM UPDATE...
FIRST BATCH OF RAIN CURRENTLY MOVING THROUGH THE REGION WHICH
APPEARS TO ASSOCIATED WITH A WEAK SHORTWAVE MOVING OVERHEAD.
LIGHTNING ACTIVITY WITH THIS FIRST CLUSTER HAS DECREASED MARKEDLY
WITH PROGRESSION THROUGH THE CWA SIGNIFYING THE CURRENT STABILITY
OF THE ATMOSPHERE. ATTENTION NOW FOCUSED ON UPSTREAM LOCATIONS
ACROSS THE WESTERN FINGER LAKES AND WESTERN SOUTHERN TIER WHERE
RECENT VIS SATELLITE TRENDS HAVE SHOWN SOME PARTIAL BREAKS IN THE
OVERLYING CLOUD COVER. LATEST RUC MLCAPE FIELDS SHOWING LATTERLY
NO INSTABILITY ACROSS UPSTATE NY THIS HR BUT HIGH-RES MODELS DO
SUGGEST A WEAK LINE FORMING ALONG THE FRONT AS IT PUSHES THROUGH
LATER THIS AFTERNOON. AS SUCH...WILL CONTINUE TO ADVERTISE A SLGT
CHC THUNDER MENTION THIS AFTERNOON/EARLY EVENING BEFORE HIGH
PRESSURE BUILDING SOUTH FROM SOUTHERN CANADA LEADS TO DRIER AIR
AND A NORTH TO SOUTH REDUCTION IN PRECIP DURING THE EVENING HRS.
MAX TEMPS ADJUSTED SLIGHTLY BASED ON CURRENT RAIN ACTIVITY MOVING
THROUGH THE AREA BUT LOW TO MID 60S STILL LOOK REASONABLE. NO
OTHER CHANGES NEEDED AT THE PRESENT TIME.
10 AM UPDATE...
MAIN CONCERN HEADING INTO THE AFTERNOON CONTINUES TO BE CONVECTIVE
DEVELOPMENT AND A LIMITED SEVERE POTENTIAL AS KINEMATIC FIELDS
REMAIN MORE THAN SUPPORTIVE FOR SEVERE WX SUSTAINMENT. THAT
SAID...MAIN LIMITING FACTOR CONTINUES TO BE EXTENSIVE CLOUD COVER
WHICH IS VIEWABLE ON LATEST VIS SATELLITE PICS THIS MORNING WHICH
WILL UNDOUBTEDLY PREVENT MAX TEMPS FROM WARMING TO THEIR MAX
POTENTIAL THIS AFTERNOON. LATEST REGIONAL RADAR TRENDS NOW SHOWING
AN AREA OF SHWRS/EMBEDDED THUNDER APPROACHING THE WESTERN SOUTHERN
TIER AND 1-HR GRIDS HAVE BEEN UPDATED TO REFLECT CURRENT ACTIVITY.
WITH ANY CLEARING DISPLACED WELL TO OUR SOUTHWEST NEAR
PITTSBURGH...ITS HARD AT THIS POINT TO SURMISE THAT REGION WILL
SEE ANY APPRECIABLE CLEARING/DESTABILIZATION PRIOR TO FROPA LATER
THIS AFTERNOON. THAT BEING SAID...WILL LEAVE A SLGT CHC THUNDER
MENTION THROUGH THIS AFTERNOON AS FRONT SLOWLY MOVES THROUGH THE
FCST AREA. CURRENT THINKING IS APPROACHING PREFERENTIAL ACTIVITY
ACROSS THE WESTERN SOUTHERN TIER WILL LIKELY STABILIZE THE LOW-
LEVEL ENVIRONMENT EVEN FURTHER WHICH WILL LIKELY KEEP ANY SEVERE
WX DEVELOPMENT IN CHECK. WILL HAVE TO WATCH MOISTURE POOLING (LOW
50 DEW POINTS) ALONG THE BOUNDARY AS IT MOVES THROUGH BUT WITH MAX
MID/UPPER-LEVEL FORCING REMAIN DISPLACED WELL TO THE
NORTH...OVERALL SEVERE WX THREAT LOOKS VERY MARGINAL AT THIS TIME.
7 AM UPDATE... FORECAST DETAILS TWEAKED WHERE NEEDED...EXPECTATIONS
AND CONCERNS FOR FRONT THIS AFTERNOON/EVENING REMAIN THE SAME AS
DISCUSSED BELOW.
PREVIOUS DISCUSSION...
WE HAVE HAD A MILD NIGHT WITH SOUTHEAST TO SOUTH FLOW. MANY
LOCATIONS NOT ALREADY IN THE 50S WILL BE WITHIN THE NEXT FEW
HOURS...THOUGH CATSKILLS/POCONOS EASTWARD WILL HOLD ON TO 40S THE
LONGEST DUE TO MARINE-INFLUENCED LAYER. WATER VAPOR IMAGERY SHOWS
STORMS THAT BLEW UP ACROSS MISSOURI/ILLINOIS AND HEADING INTO
INDIANA...ASSOCIATED WITH A SHORTWAVE THAT WILL BE A PLAYER IN OUR
WEATHER LATER TODAY. FOR NOW...STILL DRY.
MODELS EARLIER STRUGGLED WITH THE LEAD SHORTWAVE...BUT LATEST
RUNS HAVE CAUGHT ON TO IT AND AS PER VORTICITY FIELDS BRING THE
WAVE THROUGH OUR REGION 15Z-19Z. AT THIS TIME I FEEL THERE WILL BE
A FAIR BATCH OF SHOWERS MOVING IN ASSOCIATED WITH THAT
WAVE...ESPECIALLY CENTRAL TO NORTHWEST ZONES...WHICH WILL RUN WELL
AHEAD OF THE SURFACE FRONT. THE CLOUDS FROM THIS WAVE WILL
PROBABLY FURTHER INHIBIT THE ALREADY LIMITED INSTABILITY FOR
CONVECTION THIS AFTERNOON/EVENING. ALSO...THE CLOUD COVER WILL
ALSO HELP TO KEEP THE STRONG LOW LEVEL JET...40-55 KTS AT
850MB...FROM EFFECTIVELY MIXING DOWN TO THE SURFACE. THAT BEING
SAID...STILL EXPECT A PRETTY GOOD BREEZE TODAY...INCLUDING GUSTS
REACHING 20-30 MPH IN NEPA /ESPECIALLY HIGHER ELEVS/ AND 25-35 MPH
IN CENTRAL NY. LAKE PLAIN AND SYRACUSE IN PARTICULAR COULD HAVE
SOME FAIRLY STRONG DOWNSLOPING GUSTS...PERHAPS ONE OR TWO AROUND
40 MPH BUT NOT FREQUENTLY BEYOND THAT SO NO WIND ADVISORY SEEMS
WARRANTED.
MODELS ARE WELL CONVERGED ON TIMING OF SURFACE FRONT...AGAIN JUST
SLIGHTLY DELAYED FROM PRIOR MODEL RUNS...FROM CORNING-SYRACUSE
AREA 21Z...TO TOWANDA-BINGHAMTON-ONEONTA 00Z...AND THEN EXITING
SOUTHEAST OF MONTICELLO-SCRANTON BY AROUND 03Z OR SO. INSTABILITY
WILL ONLY BE MARGINAL...AN AXIS RANGING FROM VERY LITTLE TO A FEW
HUNDRED J/KG OR SO IN THE MODELS. I HAVE FOCUSED OUR SLIGHT TO LOW
CHANCE OF THUNDER TO DIRECTLY WITH THE FRONT ITSELF WHERE THERE IS
GREAT LOW LEVEL CONVERGENCE. THE LEAD SHORTWAVE MAY INTERFERE
WITH HEATING...PROBABLY AT LEAST SOMEWHAT INHIBITING INSTABILITY
FROM BEING FULLY REALIZED. WE ARE CURRENTLY NOT PEGGED FOR SLIGHT
RISK OF SEVERE BY THE STORM PREDICTION CENTER...IN FACT NOT EVEN
IN THE GENERAL THUNDER OUTLOOK AS OF 430 AM...BUT THINGS WILL
NEED TO BE MONITORED CLOSELY BECAUSE SHOULD CONVECTION GET WELL
ORGANIZED ALONG THE FRONT...A GOOD AMOUNT OF SHEAR COULD LEAD TO
STRONG GUSTS. 0-1 KM SHEAR ALONG FRONT IN THE NAM IS 30-40 KTS.
SHOWERS WILL DIMINISH FAIRLY QUICKLY BEHIND THE FRONT OVERNIGHT.
DESPITE PRECIPITABLE WATER VALUES GETTING A BIT PAST 1.25 INCHES
ALONG THE FRONT...THINGS WILL MOVE THROUGH QUICKLY ENOUGH
CONSIDERING THE FLOW ALOFT AND PACE OF FRONT...TO LIMIT AREAL
AVERAGE RAIN AMOUNTS TO A FEW TENTHS OF AN INCH IN NEPA AND
BETWEEN QUARTER AND HALF INCH IN CENTRAL NY TODAY THROUGH TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
445 AM UPDATE...
HIGH PRESSURE TEMPORARILY TAKES CHARGE WEDNESDAY...WITH SHALLOW
POOL OF COOLER STABLE POST-FRONTAL AIR. A DECENT DAY WITH HIGH
TEMPERATURES STILL NEAR CLIMATOLOGY IF NOT EVEN A TOUCH ABOVE.
FRONTAL ZONE WILL BE SITUATED TO OUR SOUTH...BUT CLOSE ENOUGH FOR MID
TO HIGH LEVEL CLOUDS TO HANG AROUND FOR THE SOUTHERN ZONES.
TOWARDS LAKE PLAIN AND MOHAWK VALLEY...PLENTY OF SUN.
FRONTAL ZONE LIFTS BACK NORTHWARD WEDNESDAY NIGHT...WITH CLOUDS
BUT ONLY SLIGHT TO LOW CHANCES OF LIGHT SHOWERS DUE TO UPPER
RIDGING AND THUS LACK OF LIFT. THIS OPENS THE DOOR TO WARM RETURN
FLOW AGAIN THURSDAY...WITH EXPECTED HIGHS IN THE 60S TO LOW
70S /WARMEST FOR LAKE PLAIN TO SYRACUSE COURTESY OF DOWNSLOPING/.
1000-500MB THICKNESSES SURGE INTO THE 560S DECAMETER RANGE.
THURSDAY LOOKS MAINLY DRY...BUT WITH A CAVEAT. WITH UPPER RIDGE
AXIS ALREADY SHIFTING EAST THURSDAY...WE GET ON EDGE OF QUICK
SOUTHWESTERLY FLOW WHICH MAY BE RIDDLED WITH LITTLE SHORTWAVES.
ODDLY ENOUGH...THE 00Z NAM EVEN SUGGESTS ONE OF THOSE WAVES
IMPACTING THE CENTRAL SOUTHERN TIER THURSDAY EVENING WITH SHOWERS
COUPLED WITH INSTABILITY. 06Z NAM THOUGH IS BACKING OFF THIS
IDEA...WHILE OTHER MODELS KEEP INSTABILITY MUCH FARTHER WEST DUE
TO FAIRLY STABLE LOW LEVELS FROM EARLIER MARINE-INFLUENCED LAYER
ADVECTING IN WEDNESDAY NIGHT/THURSDAY.
MAINLY 50S FOR LOWS THURSDAY NIGHT...WITH ONLY SLIGHT CHANCE POPS
AT BEST...AS WE AWAIT NEXT PROGRESSIVE COLD FRONT WHICH WILL STILL
BE WELL TO THE WEST /BUT INBOUND FOR FRIDAY/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
3 PM MON UPDATE... ONLY MINIMAL CHGS MADE TO THE GRIDS ATTM...AS
THE LARGE-SCALE PATN IN THE MODELS REMAINS SIMILAR.
THE MAIN FEATURE TO WATCH EARLY IN THE PD IS A FAIRLY STG AND
PROGRESSIVE COLD FRNT...SLATED TO COME THROUGH NY/PA BY FRI EVE.
WE`LL CONTINUE TO ADVERTISE LIKELY POPS THIS PD FOR SHWRS.
CONVECTIVE EVOLUTION REMAINS UNCERTAIN...OWING TO THE DEGREE OF
DESTABILIZATION AHD OF THE FRNT. FOR NOW...WE`VE THROWN IN A CHC
OF TSTMS...TO GO ALG WITH THE LIKELIHOOD OF SHWRS.
AFTERWARDS...DRIER AIR WILL GRADUALLY FILTER IN...AS A SFC HIGH
BUILDS OUT OF S-CNTRL CANADA. A FEW -SHRA/SPRINKLES COULD LINGER
FRI NGT...PERHAPS EVEN INTO EARLY SAT...UNDERNEATH THE SRN END
OF AN UPR-LVL TROUGH. OTHWS...THOUGH...THE WEEKEND INTO EARLY NEXT
WEEK LOOKS DRY AND COOL...FROM THIS EARLY VANTAGE PT.
PREV DISC... THE PERIOD BEGINS WITH A JET DIGGING A SHARP TROF
INTO THE SOUTHERN PLAINS, BRINGING MUCH BELOW AVERAGE TEMPS TO THE
CENTRAL U.S. AN EASTERN RIDGE DEVELOPS IN RESPONSE, WITH AN ACTIVE
WEATHER PATTERN DEVELOPING IN THE SOUTHWESTERLY FLOW UP THE BACK
SIDE OF THE RIDGE FROM IL/MO TO THE LOWER GREAT LAKES.
STORMS RIDING UP THROUGH THE GREAT LAKES WILL HELP PULL WARM/MOIST
AIR INTO NY/PA. THIS WILL LEAD TO A SHOWERY, MILD PATTERN AT THE
ONSET OF THE LONG TERM PERIOD. A GREAT LAKES CYCLONE INTENSIFIES
OVER NORTHERN MICHIGAN ON FRIDAY, WHILE AN ATLANTIC ANTICYCLONE
BUILDS. PRESSURE GRADIENT STRENGTHENS AS A RESULT THROUGH NY/PA.
PRECIPITATION TIMING AND CLOUD COVER WILL HAVE A LOT TO SAY ABOUT
MAX TEMPS COME FRIDAY. 925MB TEMPS OF 15-17C ARE PROGGED BY ECMWF
TO EXTEND THROUGH UPSTATE NY BY 18Z. CLOUDS ARE LIKELY TO SUPPRESS
MAXES, BUT ANY BREAKS WILL ALLOW TEMPS TO PUSH THROUGH THE 70S AND
ENHANCE INSTABILITY AHEAD OF COLD FRONT. UNTIL INSTABILITY CAN BE
BETTER PROGGED, WILL STICK TO FORECAST FOR SHOWERS AND JUST A
CHANCE OF THUNDER.
COOLER/DRIER AIR FOLLOWS THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
18Z TUE UPDATE... MVFR RESTRICTIONS ARE EXPECTED MUCH OF THE TIME
THIS AFTN (LWR CIGS/SCTD -SHRA).
A NARROW LINE/BAND OF SHRA IS EXPECTED TO ACCOMPANY A FROPA EARLY
THIS EVE (23Z-03Z)...WITH SOME IFR PSBL AT KBGM/KITH...WHILE MVFR
SHOULD CONTINUE TO BE THE PREDOMINANT CONDITION ELSEWHERE. BEHIND
THE FRNT...LWR CLDS WILL PERSIST FOR A TIME (AGN IFR PROBABLE ON
THE HILLTOPS AT KBGM/KITH...WITH MVFR ELSEWHERE).
LTR TNT...DRIER AIR WILL PUSH DOWN FROM THE NW...WITH AT LEAST PTL
CLEARING ANTICIPATED...AND A RETURN TO VFR AREA-WIDE. VFR SHOULD
THEN CONTINUE THROUGH 18Z WED.
GUSTY SRLY WINDS THROUGH EARLY EVE (UP TO 20-25 KT)...WILL SHIFT
INTO THE NW AND N OVERNIGHT AND WED.
.OUTLOOK...
WED NGT THROUGH SUN...MOSTLY VFR. LWR CIGS PSBL THU/FRI AM...AND
RESTRICTIONS PSBL FROM SHRA/TSRA FRI AFTN/EVE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/MDP
SHORT TERM...MDP
LONG TERM...DJP/MLJ
AVIATION...MLJ/MSE
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
130 PM EDT TUE APR 16 2013
.SYNOPSIS...
SOUTHERLY WIND WILL CONTINUE TO BRING CLOUDS AND THEN INCREASING
CHANCES OF SHOWERS FROM THE WEST LATER THIS MORNING. A COLD FRONT
WILL MOVE ACROSS CENTRAL NEW YORK THIS AFTERNOON...AND INTO
NORTHEAST PENNSYLVANIA THIS EVENING WITH SHOWERS AND A SLIGHT
CHANCE OF THUNDERSTORMS. ANY STORMS THAT FORM MAY CONTAIN GUSTY
WINDS. SHOWERS WILL END OVERNIGHT...LEAVING WEDNESDAY DRY. WARMER
AIR WILL RETURN TO THE REGION FOR THURSDAY...FOLLOWED BY A STRONG
COLD FRONT FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
115 PM UPDATE...
FIRST BATCH OF RAIN CURRENTLY MOVING THROUGH THE REGION WHICH
APPEARS TO ASSOCIATED WITH A WEAK SHORTWAVE MOVING OVERHEAD.
LIGHTNING ACTIVITY WITH THIS FIRST CLUSTER HAS DECREASED MARKEDLY
WITH PROGRESSION THROUGH THE CWA SIGNIFYING THE CURRENT STABILITY
OF THE ATMOSPHERE. ATTENTION NOW FOCUSED ON UPSTREAM LOCATIONS
ACROSS THE WESTERN FINGER LAKES AND WESTERN SOUTHERN TIER WHERE
RECENT VIS SATELLITE TRENDS HAVE SHOWN SOME PARTIAL BREAKS IN THE
OVERLYING CLOUD COVER. LATEST RUC MLCAPE FIELDS SHOWING LATTERLY
NO INSTABILITY ACROSS UPSTATE NY THIS HR BUT HIGH-RES MODELS DO
SUGGEST A WEAK LINE FORMING ALONG THE FRONT AS IT PUSHES THROUGH
LATER THIS AFTERNOON. AS SUCH...WILL CONTINUE TO ADVERTISE A SLGT
CHC THUNDER MENTION THIS AFTERNOON/EARLY EVENING BEFORE HIGH
PRESSURE BUILDING SOUTH FROM SOUTHERN CANADA LEADS TO DRIER AIR
AND A NORTH TO SOUTH REDUCTION IN PRECIP DURING THE EVENING HRS.
MAX TEMPS ADJUSTED SLIGHTLY BASED ON CURRENT RAIN ACTIVITY MOVING
THROUGH THE AREA BUT LOW TO MID 60S STILL LOOK REASONABLE. NO
OTHER CHANGES NEEDED AT THE PRESENT TIME.
10 AM UPDATE...
MAIN CONCERN HEADING INTO THE AFTERNOON CONTINUES TO BE CONVECTIVE
DEVELOPMENT AND A LIMITED SEVERE POTENTIAL AS KINEMATIC FIELDS
REMAIN MORE THAN SUPPORTIVE FOR SEVERE WX SUSTAINMENT. THAT
SAID...MAIN LIMITING FACTOR CONTINUES TO BE EXTENSIVE CLOUD COVER
WHICH IS VIEWABLE ON LATEST VIS SATELLITE PICS THIS MORNING WHICH
WILL UNDOUBTEDLY PREVENT MAX TEMPS FROM WARMING TO THEIR MAX
POTENTIAL THIS AFTERNOON. LATEST REGIONAL RADAR TRENDS NOW SHOWING
AN AREA OF SHWRS/EMBEDDED THUNDER APPROACHING THE WESTERN SOUTHERN
TIER AND 1-HR GRIDS HAVE BEEN UPDATED TO REFLECT CURRENT ACTIVITY.
WITH ANY CLEARING DISPLACED WELL TO OUR SOUTHWEST NEAR
PITTSBURGH...ITS HARD AT THIS POINT TO SURMISE THAT REGION WILL
SEE ANY APPRECIABLE CLEARING/DESTABILIZATION PRIOR TO FROPA LATER
THIS AFTERNOON. THAT BEING SAID...WILL LEAVE A SLGT CHC THUNDER
MENTION THROUGH THIS AFTERNOON AS FRONT SLOWLY MOVES THROUGH THE
FCST AREA. CURRENT THINKING IS APPROACHING PREFERENTIAL ACTIVITY
ACROSS THE WESTERN SOUTHERN TIER WILL LIKELY STABILIZE THE LOW-
LEVEL ENVIRONMENT EVEN FURTHER WHICH WILL LIKELY KEEP ANY SEVERE
WX DEVELOPMENT IN CHECK. WILL HAVE TO WATCH MOISTURE POOLING (LOW
50 DEWPOINTS) ALONG THE BOUNDARY AS IT MOVES THROUGH BUT WITH MAX
MID/UPPER-LEVEL FORCING REMAIN DISPLACED WELL TO THE
NORTH...OVERALL SEVERE WX THREAT LOOKS VERY MARGINAL AT THIS TIME.
7 AM UPDATE... FORECAST DETAILS TWEAKED WHERE NEEDED...EXPECTATIONS
AND CONCERNS FOR FRONT THIS AFTERNOON/EVENING REMAIN THE SAME AS
DISCUSSED BELOW.
PREVIOUS DISCUSSION...
WE HAVE HAD A MILD NIGHT WITH SOUTHEAST TO SOUTH FLOW. MANY
LOCATIONS NOT ALREADY IN THE 50S WILL BE WITHIN THE NEXT FEW
HOURS...THOUGH CATSKILLS/POCONOS EASTWARD WILL HOLD ON TO 40S THE
LONGEST DUE TO MARINE-INFLUENCED LAYER. WATER VAPOR IMAGERY SHOWS
STORMS THAT BLEW UP ACROSS MISSOURI/ILLINOIS AND HEADING INTO
INDIANA...ASSOCIATED WITH A SHORTWAVE THAT WILL BE A PLAYER IN OUR
WEATHER LATER TODAY. FOR NOW...STILL DRY.
MODELS EARLIER STRUGGLED WITH THE LEAD SHORTWAVE...BUT LATEST
RUNS HAVE CAUGHT ON TO IT AND AS PER VORTICITY FIELDS BRING THE
WAVE THROUGH OUR REGION 15Z-19Z. AT THIS TIME I FEEL THERE WILL BE
A FAIR BATCH OF SHOWERS MOVING IN ASSOCIATED WITH THAT
WAVE...ESPECIALLY CENTRAL TO NORTHWEST ZONES...WHICH WILL RUN WELL
AHEAD OF THE SURFACE FRONT. THE CLOUDS FROM THIS WAVE WILL
PROBABLY FURTHER INHIBIT THE ALREADY LIMITED INSTABILITY FOR
CONVECTION THIS AFTERNOON/EVENING. ALSO...THE CLOUD COVER WILL
ALSO HELP TO KEEP THE STRONG LOW LEVEL JET...40-55 KTS AT
850MB...FROM EFFECTIVELY MIXING DOWN TO THE SURFACE. THAT BEING
SAID...STILL EXPECT A PRETTY GOOD BREEZE TODAY...INCLUDING GUSTS
REACHING 20-30 MPH IN NEPA /ESPECIALLY HIGHER ELEVS/ AND 25-35 MPH
IN CENTRAL NY. LAKE PLAIN AND SYRACUSE IN PARTICULAR COULD HAVE
SOME FAIRLY STRONG DOWNSLOPING GUSTS...PERHAPS ONE OR TWO AROUND
40 MPH BUT NOT FREQUENTLY BEYOND THAT SO NO WIND ADVISORY SEEMS
WARRANTED.
MODELS ARE WELL CONVERGED ON TIMING OF SURFACE FRONT...AGAIN JUST
SLIGHTLY DELAYED FROM PRIOR MODEL RUNS...FROM CORNING-SYRACUSE
AREA 21Z...TO TOWANDA-BINGHAMTON-ONEONTA 00Z...AND THEN EXITING
SOUTHEAST OF MONTICELLO-SCRANTON BY AROUND 03Z OR SO. INSTABILITY
WILL ONLY BE MARGINAL...AN AXIS RANGING FROM VERY LITTLE TO A FEW
HUNDRED J/KG OR SO IN THE MODELS. I HAVE FOCUSED OUR SLIGHT TO LOW
CHANCE OF THUNDER TO DIRECTLY WITH THE FRONT ITSELF WHERE THERE IS
GREAT LOW LEVEL CONVERGENCE. THE LEAD SHORTWAVE MAY INTERFERE
WITH HEATING...PROBABLY AT LEAST SOMEWHAT INHIBITING INSTABILITY
FROM BEING FULLY REALIZED. WE ARE CURRENTLY NOT PEGGED FOR SLIGHT
RISK OF SEVERE BY THE STORM PREDICTION CENTER...IN FACT NOT EVEN
IN THE GENERAL THUNDER OUTLOOK AS OF 430 AM...BUT THINGS WILL
NEED TO BE MONITORED CLOSELY BECAUSE SHOULD CONVECTION GET WELL
ORGANIZED ALONG THE FRONT...A GOOD AMOUNT OF SHEAR COULD LEAD TO
STRONG GUSTS. 0-1 KM SHEAR ALONG FRONT IN THE NAM IS 30-40 KTS.
SHOWERS WILL DIMINISH FAIRLY QUICKLY BEHIND THE FRONT OVERNIGHT.
DESPITE PRECIPITABLE WATER VALUES GETTING A BIT PAST 1.25 INCHES
ALONG THE FRONT...THINGS WILL MOVE THROUGH QUICKLY ENOUGH
CONSIDERING THE FLOW ALOFT AND PACE OF FRONT...TO LIMIT AREAL
AVERAGE RAIN AMOUNTS TO A FEW TENTHS OF AN INCH IN NEPA AND
BETWEEN QUARTER AND HALF INCH IN CENTRAL NY TODAY THROUGH TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
445 AM UPDATE...
HIGH PRESSURE TEMPORARILY TAKES CHARGE WEDNESDAY...WITH SHALLOW
POOL OF COOLER STABLE POST-FRONTAL AIR. A DECENT DAY WITH HIGH
TEMPERATURES STILL NEAR CLIMATOLOGY IF NOT EVEN A TOUCH ABOVE.
FRONTAL ZONE WILL BE SITUATED TO OUR SOUTH...BUT CLOSE ENOUGH FOR MID
TO HIGH LEVEL CLOUDS TO HANG AROUND FOR THE SOUTHERN ZONES.
TOWARDS LAKE PLAIN AND MOHAWK VALLEY...PLENTY OF SUN.
FRONTAL ZONE LIFTS BACK NORTHWARD WEDNESDAY NIGHT...WITH CLOUDS
BUT ONLY SLIGHT TO LOW CHANCES OF LIGHT SHOWERS DUE TO UPPER
RIDGING AND THUS LACK OF LIFT. THIS OPENS THE DOOR TO WARM RETURN
FLOW AGAIN THURSDAY...WITH EXPECTED HIGHS IN THE 60S TO LOW
70S /WARMEST FOR LAKE PLAIN TO SYRACUSE COURTESY OF DOWNSLOPING/.
1000-500MB THICKNESSES SURGE INTO THE 560S DECAMETER RANGE.
THURSDAY LOOKS MAINLY DRY...BUT WITH A CAVEAT. WITH UPPER RIDGE
AXIS ALREADY SHIFTING EAST THURSDAY...WE GET ON EDGE OF QUICK
SOUTHWESTERLY FLOW WHICH MAY BE RIDDLED WITH LITTLE SHORTWAVES.
ODDLY ENOUGH...THE 00Z NAM EVEN SUGGESTS ONE OF THOSE WAVES
IMPACTING THE CENTRAL SOUTHERN TIER THURSDAY EVENING WITH SHOWERS
COUPLED WITH INSTABILITY. 06Z NAM THOUGH IS BACKING OFF THIS
IDEA...WHILE OTHER MODELS KEEP INSTABILITY MUCH FARTHER WEST DUE
TO FAIRLY STABLE LOW LEVELS FROM EARLIER MARINE-INFLUENCED LAYER
ADVECTING IN WEDNESDAY NIGHT/THURSDAY.
MAINLY 50S FOR LOWS THURSDAY NIGHT...WITH ONLY SLIGHT CHANCE POPS
AT BEST...AS WE AWAIT NEXT PROGRESSIVE COLD FRONT WHICH WILL STILL
BE WELL TO THE WEST /BUT INBOUND FOR FRIDAY/.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
3 PM MON UPDATE... ONLY MINIMAL CHGS MADE TO THE GRIDS ATTM...AS
THE LARGE-SCALE PATN IN THE MODELS REMAINS SIMILAR.
THE MAIN FEATURE TO WATCH EARLY IN THE PD IS A FAIRLY STG AND
PROGRESSIVE COLD FRNT...SLATED TO COME THROUGH NY/PA BY FRI EVE.
WE`LL CONTINUE TO ADVERTISE LIKELY POPS THIS PD FOR SHWRS.
CONVECTIVE EVOLUTION REMAINS UNCERTAIN...OWING TO THE DEGREE OF
DESTABILIZATION AHD OF THE FRNT. FOR NOW...WE`VE THROWN IN A CHC
OF TSTMS...TO GO ALG WITH THE LIKELIHOOD OF SHWRS.
AFTERWARDS...DRIER AIR WILL GRADUALLY FILTER IN...AS A SFC HIGH
BUILDS OUT OF S-CNTRL CANADA. A FEW -SHRA/SPRINKLES COULD LINGER
FRI NGT...PERHAPS EVEN INTO EARLY SAT...UNDERNEATH THE SRN END
OF AN UPR-LVL TROUGH. OTHWS...THOUGH...THE WEEKEND INTO EARLY NEXT
WEEK LOOKS DRY AND COOL...FROM THIS EARLY VANTAGE PT.
PREV DISC... THE PERIOD BEGINS WITH A JET DIGGING A SHARP TROF
INTO THE SOUTHERN PLAINS, BRINGING MUCH BELOW AVERAGE TEMPS TO THE
CENTRAL U.S. AN EASTERN RIDGE DEVELOPS IN RESPONSE, WITH AN ACTIVE
WEATHER PATTERN DEVELOPING IN THE SOUTHWESTERLY FLOW UP THE BACK
SIDE OF THE RIDGE FROM IL/MO TO THE LOWER GREAT LAKES.
STORMS RIDING UP THROUGH THE GREAT LAKES WILL HELP PULL WARM/MOIST
AIR INTO NY/PA. THIS WILL LEAD TO A SHOWERY, MILD PATTERN AT THE
ONSET OF THE LONG TERM PERIOD. A GREAT LAKES CYCLONE INTENSIFIES
OVER NORTHERN MICHIGAN ON FRIDAY, WHILE AN ATLANTIC ANTICYCLONE
BUILDS. PRESSURE GRADIENT STRENGTHENS AS A RESULT THROUGH NY/PA.
PRECIPITATION TIMING AND CLOUD COVER WILL HAVE A LOT TO SAY ABOUT
MAX TEMPS COME FRIDAY. 925MB TEMPS OF 15-17C ARE PROGGED BY ECMWF
TO EXTEND THROUGH UPSTATE NY BY 18Z. CLOUDS ARE LIKELY TO SUPPRESS
MAXES, BUT ANY BREAKS WILL ALLOW TEMPS TO PUSH THROUGH THE 70S AND
ENHANCE INSTABILITY AHEAD OF COLD FRONT. UNTIL INSTABILITY CAN BE
BETTER PROGGED, WILL STICK TO FORECAST FOR SHOWERS AND JUST A
CHANCE OF THUNDER.
COOLER/DRIER AIR FOLLOWS THE COLD FRONT FOR THE WEEKEND.
&&
.AVIATION /17Z TUESDAY THROUGH SATURDAY/...
DRY OVERCAST CONDITIONS ARE EXPECTED THROUGH THIS MORNING. CIGS
WILL BE MOSTLY VFR WITH OCCASIONAL MVFR AROUND 12Z AT ELM/BGM/AVP.
SHOWERS WILL DEVELOP BY EARLY AFTERNOON ACROSS NY STATE AND LATER
THIS AFTERNOON IN NORTHEAST PA. A FEW HVY DOWNPOURS WITH SOME
THUNDER AND LIGHTNING WILL BE POSSIBLE LATER THIS AFTERNOON
ESPECIALLY AT AVP... BUT DURATION AND PROBABILITY FOR THIS IS
SMALL ENOUGH SO THAT IT IS NOT INCLUDED IN THE TAFS AT THIS TIME.
SHOWERS WILL END TUESDAY EVENING WITH VFR CONDITIONS RETURNING.
WINDS WILL BE FROM THE SOUTH-SOUTHWEST INCREASING TO 10 TO 20 KTS
WITH GUSTS AS HIGH AS 30 KTS TODAY... SHIFTING TO NORTHWEST AT 10
TO 20 KTS LATE THIS AFTERNOON THROUGH THIS EVENING THEN
DIMINISHING TO LESS THAN 10 KTS LATER TUESDAY NIGHT.
.OUTLOOK...
WED THROUGH SAT...MOSTLY VFR. LWR CIGS PSBL THU/FRI AM...AND
RESTRICTIONS PSBL FROM SHRA/TSRA FRI AFTN/EVE.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...CMG/MDP
SHORT TERM...MDP
LONG TERM...DJP/MLJ
AVIATION...MSE
AREA FORECAST DISCUSSION
NWS SAN ANGELO TX
340 PM CDT TUE APR 16 2013
.SHORT TERM...
FRONTAL BOUNDARY HAS SAGGED SOUTH THROUGH THE INTERSTATE 20 CORRIDOR
THIS AFTERNOON...WITH NORTH WINDS AT SWEETWATER AND BRIEFLY AT
ABILENE. LOOKS LIKE THE FRONT HAS PULLED UP STATIONARY OR MAYBE
DRIFTING WEST...WITH MODELS SUGGESTING A RETREAT NORTHWARD AS A WARM
FRONT THIS EVENING. HOW FAR NORTH IT RETREATS IS A HUGE
QUESTION...WITH THE GFS SHOWING A RAPID RETREAT AND THE RUC MUCH
SLOWER. AT THIS POINT...WITH THE GFS HAVING LARGELY MISSED HOW FAR
SOUTH THE FRONT WOULD MAKE IT TODAY...AND WITH TEMPERATURES IN THE
50S AND STILL GOOD NORTHEAST FLOW ACROSS OKLAHOMA...WILL LEAN
TOWARDS A SOMEWHAT SLOWER RETREAT.
VISIBLE SATELLITE SHOWING A LITTLE CU TRYING TO GO ALONG AND JUST
NORTH OF THE FRONT ACROSS THE BIG COUNTRY. CAP IS STILL STRONG...BUT
AT LEAST A FEW STORMS LOOK VERY POSSIBLE...AS THE CAP WEAKENS
LOCALLY AND AS A WEAK UPPER LEVEL SHORTWAVE APPROACHES. EXPECT A FEW
ISOLATED STORMS TO DEVELOP SOMEWHERE CLOSE TO ABILENE OR SWEETWATER
LATE THIS AFTERNOON AND CONTINUE INTO THE MID EVENING HOURS. NEAR
RECORD HIGH TEMPERATURES HERE IN SAN ANGELO...ALONG WITH DEWPOINTS
AROUND 60...ARE LEADING TO A VERY UNSTABLE AIR MASS. GIVEN CAPE
VALUES IN EXCESS OF 2500 J/KG...IF A STORM CAN DEVELOP...EXPECT IT
TO TRY TO REACH SEVERE LEVELS PRETTY QUICK.
EXPECT FRONT TO DRIFT NORTH THROUGH THE EVENING...PROBABLY BACK INTO
THE NORTHERN BIG COUNTRY BY LATE THIS EVENING...AND BACK OUT OF WEST
CENTRAL TEXAS BY SUNRISE. MILD AGAIN SOUTH OF THE BOUNDARY...WITH
READINGS HAVING A HARD TIME DROPPING BELOW 70. A LITTLE COOLER
ACROSS THE NORTHERN BIG COUNTRY...ALTHOUGH TEMPERATURES THERE MAY
EVEN CLIMB SLIGHTLY BY MORNING.
MAIN UPPER TROUGH MOVING INTO THE ROCKIES WEDNESDAY AFTERNOON. BEST
LIFT WAITS UNTIL WEDNESDAY NIGHT...BUT IT WILL AID THE DRYLINE IN
STRENGTHENING AND MOVING EAST. BY AFTERNOON...DRYLINE WILL LIKELY BE
SOMEWHERE ACROSS THE WESTERN BIG COUNTRY AND CONCHO VALLEY. CAP WILL
STILL BE STRONG...BUT SHOULD BEGIN TO ERODE BY LATE IN THE
AFTERNOON. WILL CONTINUE THE SLIGHT CHANCE POPS DURING THE
AFTERNOON...WITH ODDS INCREASING QUITE A BIT AFTER DARK.
07
.LONG TERM...
CURRENT WEATHER...WV IMAGERY IS SHOWING A TROF AMPLIFYING ACROSS THE
WESTERN US. THIS AFTERNOON...STATIONARY FRONT EXTENDS ACROSS
EXTREME SOUTHEAST OKLAHOMA...NORTHWEST TEXAS AND THE NORTHERN
PERMIAN BASIN. ALSO...MODIFIED ARCTIC HIGH PRESSURE SURFACE RIDGE
WAS OVER MONTANA AND THE NORTHERN PLAINS.
WEDNESDAY NIGHT...HOW ARE THESE TWO FEATURES GOING TO AFFECT WEST
CENTRAL TEXAS WITH POSSIBLE SEVERE WEATHER. THE ALOFT PART IS
PRETTY STRAIGHT FORWARD...WITH TROF INTENSIFYING AND MOVING EAST
PUTTING THE SOUTHERN PLAINS IN STRONG SOUTHWEST FLOW. ALSO...THE
GFS MODEL INDICATING GOOD POLAR AND SUBTROPICAL JET DIVERGENCE AT
POSSIBLE PRIME SEVERE WEATHER TIME/WEDNESDAY AFTERNOON AND NIGHT/.
THE SURFACE PART IS MORE COMPLEX. THE ECMWF AND NAM MODELS ARE
KEEPING THE FRONT FURTHER SOUTH FROM ALONG AN OKLAHOMA CITY TO
TULIA LINE THROUGH WEDNESDAY. THE GFS IS MUCH FURTHER NORTH ALONG
A GUYMON TO KANSAS CITY LINE. THE GFS MAY BE STRUGGLING DUE
PARTLY TO THE WARM EQUATION NUMBERS BEING INPUTED ON APRIL 1ST.
GOING MORE WITH THE NAM AND ECMWF DUE TO ARCTIC AIR ALREADY IN
PLACE TO OUR NORTH AND A NEGATIVE NAO PATTERN STILL OVER THE
EASTERN US. HOWEVER...GOOD SURFACE CYCLOGENESIS IS A GOOD BET
WEDNESDAY OVER THE SOUTHERN PLAINS DUE TO STRONG DYNAMICS JUST
UPSTREAM. THERE ARE A FEW MORE TWISTS AND TURNS IN THIS FORECAST.
STAY TUNED.
THE BEST CHANCE OF MORE WIDESPREAD/POSSIBLY SIGNIFICANT/SEVERE
WEATHER WILL BE WEDNESDAY AND WEDNESDAY NIGHT ACROSS THE SOUTHERN
PLAINS. THE DAY2 OUTLOOK BY SPC OF A MODERATE RISK OVER OKLAHOMA
AND EXTREME NORTHWEST TEXAS LOOKS GOOD. THE WARM SECTOR WILL BE
PRIMED AHEAD OF THE DRYLINE AND SOUTH OF STATIONARY FRONT.
DEWPOINTS WILL BE IN THE MID TO UPPER 60S ALONG WITH STRONG
INSTABILITY/MLCAPES OF 2000 TO 3000 J/KG/. WITH THE ADDITION OF
STRONG SHEAR...SUPERCELLS ARE A GOOD BET MAINLY DURING THE LATE
AFTERNOON AND EARLY EVENING. AT LEAST FOR NOW...THE FRONT WILL
MOVE NORTH TO THE I-40 CORRIDOR BY 00Z THU. SO MORE ORGANIZED
SEVERE CONVECTION IS MORE LIKELY ACROSS THE BIG COUNTRY LATE
WEDNESDAY AFTERNOON AND EVENING. ALSO...THE TEXAS TECH 3KM WRF IS
INDICATING A LINE OF CONVECTION FROM ABILENE TO SAN ANGELO JUST
AFTER MIDNIGHT. THE MAIN HAZARDS WILL BE LARGE HAIL AND DAMAGING
WINDS...ALONG WITH ISOLATED TORNADOES POSSIBLE. GOING WITH LKLY
POPS ACROSS THE FAR EASTERN COUNTIES AND MAINLY CHC ELSEWHERE FOR
WEDNESDAY NIGHT.
THURSDAY THROUGH TUESDAY...COOLER FOR THURSDAY AND FRIDAY WITH
HIGHS MAINLY IN THE 60S. A WARMING TREND BY THIS WEEKEND WITH
HIGHS IN THE UPPER 70S TO LOWER 80S. THE COLDEST MORNING WILL BE
FRIDAY WITH LOWS IN THE 30S. IF SKIES ARE CLEAR AND WINDS
CALM...THEN TEMPS MAY DROP TO NEAR FREEZING...ESPECIALLY IN LOW
LYING AREAS AND RIVER VALLEYS.
21
&&
.PRELIMINARY POINT TEMPS/POPS...
ABILENE 68 86 56 62 36 / 20 20 40 10 5
SAN ANGELO 70 91 58 65 38 / 10 20 30 10 5
JUNCTION 70 89 63 70 39 / 5 20 50 10 5
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
FORECAST DISCUSSION FOR ROUTINE AFTERNOON FORECAST ISSUANCE
.SHORT TERM...TONIGHT AND WEDNESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW HIGH PRESSURE
CENTERED OVER CENTRAL CANADA AND A RIDGE AXIS EXTENDING INTO THE
NORTHERN MISSISSIPPI VALLEY. A WEAK COLD FRONT IS EXTENDING ACROSS
LAKE SUPERIOR AND NORTHERN MINNESOTA...WHICH IS CONTRIBUTING TO THE
WIDESPREAD STRATO-CU FIELD OVER NORTHERN PARTS OF WISCONSIN. THIS
STRATO-CU FIELD HAS BEEN SLOWLY RETREATING NORTHWARD THIS
AFTERNOON...AND CLEARING SKIES ARE NOW APPROACHING WAUSAU AND
MARINETTE AT THIS HOUR. MEANWHILE...CONVECTION IS OCCURRING NORTH
OF A STATIONARY FRONT LOCATED ACROSS THE OHIO VALLEY. AS THIS FRONT
LIFTS NORTH TOMORROW...THE MAIN FORECAST CONCERN BECOMES TIMING OF
THE INCOMING PRECIPITATION.
TONIGHT...AS CONVERGENCE ALONG A REINFORCING COLD FRONT
WEAKENS...CANADIAN HIGH PRESSURE WILL FEED IN DRIER AIR...BROUGHT IN
BY LIGHT NE WINDS. MAY SEE SCT CLOUD COVER LINGER INTO THE EARLY
EVENING HOURS OVER N-C WISCONSIN BEFORE DRY AIR EVENTUALLY WINDS OUT
AND SKIES TURN MOSTLY CLEAR. IF AND WHEN THIS OCCURS...TEMPS WILL
HAVE POTENTIAL TO TANK OVER N-C WISCONSIN WHERE THERE REMAINS DEEP
SNOW PACK. HAVE DROPPED LOW TEMPS CONSIDERABLY. OTHERWISE...A WARM
FRONT WILL BE LIFTING NORTH ACROSS THE MID-MISSISSIPPI VALLEY...AND
MID CLOUDS WILL SPREAD NORTH OVER CENTRAL AND EAST-CENTRAL WISCONSIN
AFTER MIDNIGHT. THE DRY AIR FEED TO KEEP PRECIP WELL SOUTH OF THE
REGION THOUGH. LOWS RANGING FROM AROUND 20 DEGREES NORTH TO THE MID
30S SOUTH.
WEDNESDAY...THE WARM FRONT WILL CONTINUE TO GRADUALLY LIFT NORTH
OVER CENTRAL AND NORTHERN ILLINOIS. DRY NE FEED OF AIR WILL TRY TO
HOLD BACK PRECIP DURING THE MORNING...AND IT LOOKS LIKE MODELS HAVE
SLOWED THE NORTHERLY PROGRESS OF PRECIP CHANCES. WILL GO DRY WITH
THE FORECAST THROUGH 18Z. AFTER THAT TIME THOUGH...SOUTHWEST FLOW
WILL STRENGTHEN OVER THE FRONT...WHICH SHOULD LEAD TO PRECIP MOVING
INTO CENTRAL AND EAST-CENTRAL WISCONSIN DURING THE AFTERNOON. THE
PRECIP WILL BE FIGHTING THE DRY AIR...SO THINK THE HEAVIER RAIN WILL
NOT ARRIVE UNTIL WEDNESDAY NIGHT...AND FAR NE WISCONSIN MAY NOT SEE
A DROP UNTIL AFTER 00Z AS WELL. HIGH TEMPS WILL LIKELY OCCUR MIDDAY
OR EARLY AFTERNOON BEFORE CLOUDS THICKEN AND/OR PRECIP STARTS
FALLING. PTYPE LIKELY TO BE TRICKY OVER N-C WISCONSIN WHERE THERE
WILL BE A +4C WARM NOSE ABOVE SURFACE TEMPS NEAR FREEZING. PREVIOUS
SHIFT INCLUDED A RAIN/SLEET MIX...AND THAT LOOKS GOOD COMPARED TO
THE PROJECTED SURFACE WET BULB TEMPS. HIGHS IN THE LOW TO MID 40S.
.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY
ISSUED AT 308 PM CDT TUE APR 16 2013
ACTIVE AND COMPLEX WEATHER SITUATION WITH POTENTIAL FOR A COUPLE
ROUNDS OF SIGNIFICANT PRECIPITATION FOR THE SECOND HALF OF THE
WORK WEEK. SIGNIFICANT TROUGH WILL GRADUALLY SWING INTO THE HIGH
PLAINS BY 12Z THURSDAY AND BECOME NEGATIVELY TILTED AND DEEPEN BY
FRIDAY AFTERNOON.
AS PREVIOUSLY ADVERTISED...STRONG 850 MB JET WILL DEVELOP OVER THE
PLAINS EARLY WEDNESDAY EVENING AND WILL BE THE DRIVING FORCE FOR
STRONG WAA/LIFT AND SIGNIFICANT MOISTURE TRANSPORT INTO THE WESTERN
GREAT LAKES WEDNESDAY NIGHT. LARGE AREA OF MODERATE TO HEAVY
PRECIPTATION IS FORECAST TO BREAKOUT FROM EASTERN NEBRASKA TO
SOUTHWEST WISCONSIN AND SPREAD NORTHEAST ACROSS THE FORECAST AREA
OVERNIGHT INTO EARLY THURSDAY. PRECIPITABLE WATER VALUES OVER THE
MISSISSIPPI VALLEY NORTHWARD INTO WISCONSIN EXPECTED TO BE WELL
ABOVE NORMAL FOR THIS TIME OF YEAR. COMBINATION OF STRONG
FORCING...ANOMALOUSLY HIGH PRECIPITABLE WATER WILL LEAD MODERATE TO
HEAVY RAINFALL. THE GENERAL CONCENSUS OF THE LATEST GUIDANCE SEEMS
TO BE FOCUSING THE MAXIMUM QPF OVER ABOUT THE SOUTHEAST THIRD OF THE
STATE. HELD ONTO THUNDER POTENTIAL...ESPECIALLY OVER THE FOX VALLEY
AS WELL WEDNESDAY NIGHT. CANADIAN MODEL WAS FURTHEST NORTH THAN THE
OTHER GUIDANCE DURING THIS PERIOD...THUS WAS DISCONTED. THE AREA OF
HEAVIEST RAINFALL SHOULD BE EAST OF THE FORECAST AREA BY AROUND NOON
THURSDAY. ACROSS THE NORTHWEST PORTION OF THE FOPRECAST
AREA...APPEARS BOUNDARY LAYER TEMPERATURES WILL BE VERY CLOSE TO
FREEZING...THUS STILL FEEL THERE IS POTENTIAL FOR SOME FREEZING
RAIN...MIXED WITH SLEET AND WET SNOW PARTICULARLY IN THE 06Z TO 12Z
PERIOD THURSDAY MORNING.
UPPER SYSTEM THEN BECOMES NEGATIVELY TILTED THURSDAY EVENING WITH
SURFACE WAVE RAPIDLY INTENSIFYING. PROBLEM IS THAT STILL MUCH
DESCREPANCY IN MODEL GUIDANCE WITH RESPECT TO THE RATE OF
DEEPENING AND MOVEMENT OF THE SURFACE LOW. THUS...HAD TO REAMIN
SOMEWHAT BROAD BRUSH ON QPF AMOUNTS ACROSS THE FORECAST AREA. IT
DOES APPEAR THAT BY EARLY FRIDAY MORNING ENOUGH COLD AIR WILL BE
DRAWN INTO THE SYSTEM TO TURN THE PRECIPITATION OVER TO SNOW. LATER
SHIFTS SHOULD BE ABLE GET A BETTER HANDLE ON THE SYSTEM EVOLUTION
AND ASSOCIATED PRECIPITATION TYPES.
GIVEN THE POTENTIAL FOR A COUPLE ROUNDS OF MODERATE TO HEAVY
RAINFALL...MELTING SNOW AND MANY RIVERS AT OR ABOVE FLOOD STAGE
ALREADY...AREAL FLOOD WATCH HAS BEEN ISSUED. SEE ASSOCIATED
HYDROLOGY DISCUSSION FOR DETAILS BELOW.
LOOKS LIKE QUIETER AND DRIER CONDITIONS TO RETURN OVER THE
UPCOMING WEEKEND...ALTHOUGH TEMPERATUES WILL REMAIN WELL BELOW
NORMAL INTO EARLY NEXT WEEK.
&&
.AVIATION...FOR 18Z TAF ISSUANCE
ISSUED AT 1222 PM CDT TUE APR 16 2013
12Z SOUNDINGS INDICATE CLOUD COVER OVER CENTRAL AND
NORTHERN WISCONSIN IS RELATIVELY SHALLOW...SO ANTICIPATING CLOUDS TO
BREAK UP WITH HEATING THIS AFTERNOON. REGARDLESS...CIGS SHOULD
INCREASE TO VFR THIS AFTERNOON. HIGH PRESSURE WILL THEN HANG AROUND
THE REGION TONIGHT AS MID CLOUDS INCREASE AHEAD OF THE NEXT SYSTEM
DEVELOPING OVER THE PLAINS. A WARM FRONT THEN LIFTS NORTH INTO
NORTHERN ILLINOIS ON WEDNESDAY. CLOUDS WILL LOWER AND THICKEN
THROUGH THE DAY AS MOISTURE FLOWS NORTH. INITIAL LOW LEVEL DRY AIR
WILL HOLD BACK THE PRECIPITATION SOMEWHAT...BUT STILL EXPECT LIGHT
RAIN...POSSIBLY MIXED WITH SNOW OVER NORTHERN WISCONSIN TO ARRIVE
WEDNESDAY AFTERNOON.
&&
.HYDROLOGY...
ISSUED AT 308 PM CDT TUE APR 16 2013
POTENTIAL OF FLOODING ON THE INCREASE THIS WEEK WITH EVEN LONG
TERM ISSUES THROUGH APRIL.
A STRENGTHENING LOW PRESSURE SYSTEM WILL TRACK NORTHEAST TOWARD THE
GREAT LAKES REGION THROUGH FRIDAY. GULF MOISTURE WILL WORK
NORTHWARD TO PRODUCE WELL ABOVE NORMAL PRECIPITABLE WATER AMOUNTS
FOR THIS TIME OF THE YEAR. RIVERS OVER MUCH OF CENTRAL AND EAST
CENTRAL WISCONSIN ALREADY RUNNING HIGH. ADDITIONAL OR LINGERING
SNOW MELT WILL BE AVAILABLE OVER CENTRAL WISCONSIN RIVERS WHILE
AREAS WITH LITTLE SNOW LEFT...THE GROUND IS SATURATED ALONG WITH A
DEPARTING FROST TO PRODUCE ABOVE NORMAL RUN OFF. CONSENSUS OF
AVAILABLE MODEL RUNS FOR A TOTAL RAINFALL AMOUNT FROM LATE
WEDNESDAY AFTERNOON THROUGH FRIDAY MORNING INDICATE AROUND 2
INCHES OF RAIN SOUTHEAST OF A LINE FROM GREEN BAY TO WAUTOMA...AND
UP TO 1.5 INCHES NORTHWARD. THE RAIN WILL BE FOCUSED ALONG OR NEAR
A SOUTHWEST TO NORTHEAST BOUNDARY EXTENDING OVER SOUTHEAST
WISCONSIN. ANY THUNDERSTORMS WHICH CAN DEVELOP...WILL LIKELY
INCREASE THE RAINFALL TOTALS. NORTH CENTRAL WISCONSIN COULD SEE A
RAIN TO SNOW MIX BY FRIDAY FOR LESSER RAINFALL BUT ADDITIONAL
SNOWFALL TO THE PERSISTENT SNOW PACK. WILL ISSUE A FFA AREAL FLOOD
WARNING FOR CENTRAL AND EAST CENTRAL WISCONSIN THROUGH FRIDAY.
WILL CONSIDER AN ESF NORTH. THE AREAL FLOOD WARNING WILL LIKE
TRANSITION TO RIVER FLOOD WARNINGS BY THIS WEEKEND.
FOR A LONGER TERM FLOODING ISSUE DEVELOPING...THE INCREASING FLOWS
ON THE FOX AND WOLF RIVERS COMING INTO LAKE WINNEBAGO WILL
EVENTUALLY CAUSE THE LAKE TO RISE AND REMAIN FAIRLY HIGH FOR MUCH
OF APRIL IF PERIODS OF RAIN CONTINUE. THE COMBINATION OF STRONG
WINDS WITH HIGHER THAN NORMAL LAKE WINNEBAGO LAKE LEVELS WILL
INCREASE THE POTENTIAL OF SHORELINE FLOODING. HIGH LAKE WINNEBAGO
LEVELS WILL LIKELY TEND TO PRODUCE LONG TERM HIGH LEVELS UPSTREAM
ON THE WOLF AND FOX RIVERS THROUGH APRIL...AGAIN DEPENDING
ADDITIONAL RAINFALL.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY MORNING FOR
WIZ020>022-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......ESB
AVIATION.......MPC
HYDROLOGY......MPC
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1213 PM CDT TUE APR 16 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 354 AM CDT TUE APR 16 2013
WATER VAPOR IMAGERY AND RAP 500MB ANALYSIS SHOWS A BROAD/RELATIVELY
DEEP UPPER TROUGH AXIS SITUATED OVER THE WEST COAST/INTERMOUNTAIN
REGION. SOUTHWEST FLOW ALOFT OUT F THIS TROUGH WAS SPILLING QUITE A
BIT OF MID/HIGH CLOUD INTO THE REGION. AT THE SURFACE...THE FORECAST
AREA WAS STILL UNDER THE INFLUENCE OF THE LOW PRESSURE THAT BROUGHT
A WINTRY MIX/RAINFALL INTO THE AREA OVER THE WEEKEND. CYCLONIC FLOW
AROUND THE LOW OVER SOUTHERN ONTARIO WAS PRODUCING AN EXTENSIVE
STRATOCUMULUS FILED ACROSS NORTHERN MN INTO NORTHER WI.
OTHERWISE...TEMPERATURES AT 3 AM WERE IN THE 30S.
MAIN FORECAST CHALLENGE IN THE SHORT TERM WILL BE CLOUDS AND
TEMPERATURES THROUGH TONIGHT.
16.00Z NCEP MODEL SUITE AS WELL AS THE ECMWF AND GEM ALL IN GOOD
AGREEMENT IN THE SHORT TERM.
FOR TODAY...WILL SEE THE LOW OVER ONTARIO LIFT FARTHER EAST INTO
QUEBEC...WITH HIGH PRESSURE BUILDING IN FROM THE NORTHERN PLAINS.
THIS WILL KEEP US DRY...BUT SOUTHWEST FLOW ALOFT WILL CONTINUE TO
SPILL MID/HIGH CLOUD INTO THE REGION. NOT TOO CONFIDENT HOW THICK
THIS CLOUD COVER WILL BE. BUFKIT SHOWS ALTERNATE THICKENING/THINNING
THROUGH THE DAY. FEEL WE SEE SOMEWHERE BETWEEN 40-60 PERCENT
OPAQUENESS FOR PARTLY TO MOSTLY SUNNY CONDITIONS. TEMPERATURES TODAY
EXPECTED TO TOP OFF IN THE MIDDLE 40S ACROSS NORTH CENTRAL WI...TO
THE LOWER 50S ACROSS PORTIONS OF NORTHEAST IOWA INTO SOUTHWEST WI.
CLOUDS WILL THEN THICKEN TONIGHT AHEAD OF FAIRLY STRONG CYCLOGENESIS
EAST OF THE COLORADO ROCKY MOUNTAIN FRONT WITH INCREASING MOISTURE
TRANSPORT AND ISENTROPIC LIFT. MOISTURE WILL BE BATTLING DRY AIR
INITIALLY...BUT FEEL SOME RAIN WILL BE POSSIBLE ACROSS NORTHEAST
IA/SOUTHEAST MN/FAR SOUTHWEST WI TOWARD MORNING. OTHERWISE...WITH
THICKENING CLOUDS...LOOK FOR TEMPERATURES TO RANGE FROM NEAR 30
ACROSS NORTH CENTRAL WI...TO THE MIDDLE AND UPPER 30S ACROSS
NORTHEAST IA INTO SOUTHWEST WI.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 354 AM CDT TUE APR 16 2013
LOOK FOR RAIN TO OVERSPREAD THE AREA ON WEDNESDAY AS STRONG LOW
PRESSURE MOVING OUT INTO THE PLAINS INCREASES MOISTURE TRANSPORT
INTO THE AREA. NAM ALSO INDICATING SOME ELEVATED MUCAPE OF A COUPLE
HUNDRED J/KG GOING INTO THE AFTER NOON FOR PERHAPS A CLAP OR TWO OF
THUNDER.
RAINFALL EXPECTED TO REALLY PICK UP OVER THE AREA WEDNESDAY
AFTERNOON/NIGHT AS THE LOW MOVES FROM MO INTO SOUTHEAST WI. SREF
INDICATING INCREASING 850-700MB FRONTOGENESIS OVER THE FORECAST AREA
NORTHWEST OF THE LOW ALONG WITH INCREASING MOISTURE TRANSPORT...
WITH PRECIPITABLE WATERS MOVING INTO THE 1-1.5 INCH RANGE. RAIN
RATES COULD GET MODERATE TO HEAVY AT TIMES GIVEN THIS SCENARIO. RAIN
THEN EXPECTED TO TAPER OFF ON THURSDAY AS THE LOW PULLS INTO LOWER
MI. THINKING THAT FOCUSED FORCING ALONG WITH MUCH HIGHER THAN NORMAL
PRECIPITABLE WATER VALUES WILL YIELD RAINFALL AMOUNTS SOMEWHERE IN
THE 1.5-3.5 INCH RANGE WITH A FEW LOCALLY HIGHER AMOUNTS GIVEN THE
EMBEDDED THUNDERSTORM POTENTIAL. HYDROLOGY EXPECTED TO BECOME AN
ISSUE ONCE AGAIN WITH RIVERS RUNNING FAIRLY HIGH RIGHT NOW. MORE ON
THIS IS COVERED IN THE HYDROLOGY SECTION BELOW. CONCERN IS
INCREASING THAT A FLOOD WATCH MAY BECOME NECESSARY AS WELL WITH
SATURATED GROUND AND POTENTIAL FOR OVERLAND FLOODING IN ADDITION TO
RIVER FLOODING SINCE OUR 6-HRLY FLASH FLOOD GUIDANCE IS ONLY RUNNING
2-3 INCHES. WILL HAVE THE DAY SHIFT ASSESS THIS WITH THE 12Z MODEL
RUNS.
ATTENTION THEN TURNS TO SIGNIFICANT SNOWFALL POTENTIAL FOR THURSDAY
NIGHT INTO FRIDAY. MODELS ARE BECOMING MORE IN AGREEMENT AND
CONSISTENT WITH INCREASING SNOW SIGNAL FOR THE AREA. ECMWF/GFS/GEM
ALL BRING ANOTHER WAVE OF LOW PRESSURE UP ALONG THE EXISTING
BAROCLINIC ZONE AS A VIGOROUS MID-LEVEL TROUGH/CLOSED LOW MOVES
TOWARD THE AREA FROM THE PLAINS. STRONG DEFORMATION ZONE THEN SETS
UP ACROSS THE NORTHWEST HALF OF THE FORECAST AREA. LATEST GFS COB
WANTS TO PRODUCE 8+ INCHES/LOCALLY HIGHER AMOUNTS NORTHWEST OF A
LINE ROUGHLY RUNNING FROM MEDFORD AND LA CROSSE WI...TO NEAR OELWEIN
IA. HEADLINES WILL LIKELY BE NEEDED. WILL PASS THIS ONTO THE
DAYSHIFT AS WELL FOR FURTHER ASSESSMENT.
FRIDAY NIGHT THROUGH SATURDAY LOOKS DRY WITH HIGH PRESSURE MOVING
IN.
PRECIPITATION CHANCES WILL RETURN SATURDAY NIGHT THROUGH MONDAY AS
LOW PRESSURE MOVES ACROSS THE NORTHERN PLAINS INTO THE UPPER
MISSISSIPPI RIVER VALLEY REGION.
OTHERWISE...LOOK FOR BELOW NORMAL TEMPERATURES TO CONTINUE THROUGH
THE WEEKEND...POSSIBLY GETTING TO NEAR NORMAL BY MONDAY.
&&
.AVIATION...THROUGH 18Z WEDNESDAY
1208 PM CDT TUE APR 16 2013
MVFR CLOUDS TO SLOWLY CLEAR THIS AFTERNOON AND GIVE WAY TO VFR
CONDITIONS UNTIL A MAJOR WEATHER SYSTEM MOVES IN FOR WEDNESDAY AND
THURSDAY.
MOISTURE WILL INCREASE SUBSTANTIALLY IN THE ATMOSPHERE OVER THE
TAF SITES WEDNESDAY MORNING WITH DETERIORATING CONDITIONS EXPECTED
THROUGH THE DAY IN -RA/RA. PERIODIC IFR CIGS/VSBYS ARE POSSIBLE
LATER WEDNESDAY AND INTO THURSDAY. THUS...CONDITIONS WILL BE BEST
FOR AVIATION USERS IN THE MORNING WEDNESDAY.
A CHANGE TO ACCUMULATING SNOW WILL OCCUR THURSDAY NIGHT AT KRST
AND IFR CONDITIONS LOOK LIKELY INTO FRIDAY.
&&
.HYDROLOGY...MAINLY WEDNESDAY AND WEDNESDAY NIGHT
ISSUED AT 354 AM CDT TUE APR 16 2013
ADDITIONAL RAINFALL WED/WED NIGHT/THU POSES A FLOODING THREAT FOR
MOST IF NOT ALL RIVERS AND STREAMS IN OUR FORECAST AREA. RUNOFF FROM
EXPECTED 1.5 TO 3.5 INCHES OF RAINFALL FROM WED THROUGH THU WILL
LIKELY PRODUCE ADDITIONAL RISES ON THE TRIBUTARY RIVERS/ STREAMS
THAT ARE ALREADY RUNNING HIGH FROM RECENT RAINFALL AND SNOW MELT
THIS PAST WEEK. GIVEN THIS EXPECTED RAINFALL ALONG WITH LOCALIZED
HIGHER RAINFALL RATES...ADDITIONAL FLOODING IS POSSIBLE IF NOT
LIKELY ON THE TRIBUTARY RIVERS LATER IN THE WEEK INTO THE WEEKEND.
WILL CONTINUE HYDROLOGIC OUTLOOK PRODUCT ADDRESSING THE
RAIN/FLOODING THREATS LATER IN THE WEEK.
LOOK FOR WATER LEVELS ON THE MISSISSIPPI RIVER TO REMAIN NEARLY
STEADY OR GRADUALLY RISE THIS WEEK AS RUNOFF FROM RECENT RAINS AND
SNOWMELT MOVES DOWNSTREAM. THE ADDITIONAL RAINS ON WEDNESDAY THROUGH
THURSDAY WOULD CREATE ADDITIONAL RISES ON THE MISSISSIPPI
RIVER...BUT MOST OF THESE RISES FROM THE WED-THU RAINS EXPECTED NOT
TO SHOW UP IN THE MISSISSIPPI RIVER UNTIL EARLY NEXT WEEK.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1208 PM CDT TUE APR 16 2013
WI...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR WIZ017-029-032>034-041>044-053>055-061.
MN...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR MNZ079-086>088-094>096.
IA...FLOOD WATCH FROM WEDNESDAY AFTERNOON THROUGH LATE THURSDAY NIGHT
FOR IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...DAS
LONG TERM....DAS
AVIATION...BAUMGARDT
HYDROLOGY....DAS/RRS