Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/12/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
1144 PM MDT TUE APR 9 2013
.UPDATE...
ISSUED AT 751 PM MDT TUE APR 9 2013
CANCELLED THE WINTER WX ADVISORIES FOR THE SERN PLAINS.
UPDATE ISSUED AT 601 PM MDT TUE APR 9 2013
UPDATED FOR EXPIRATION OF SOME OF THE SNOW ADVISORY AREAS AT 6 PM.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 320 PM MDT TUE APR 9 2013
UPPER LOW OVER AZ AND UT IS FINALLY LIFTING TO THE NORTHEAST INTO
WESTERN CO AS 120 KT JET LIFTS TO THE NORTHEAST ACROSS CEN/SRN NM.
UPPER LEVEL IMPULSES HAVE BROUGHT ROUNDS OF SNOW TO THE AREA TODAY.
THE FIRST WAVE CAME ACROSS THIS MORNING AND BROUGHT A BRIEF ROUND OF
SNOW TO THE I-25 CORRIDOR...AND BRIEF BLIZZARD
CONDITIONS...ESPECIALLY AT THE KPUB AIRPORT BETWEEN 9 AM AND 11 AM.
THIS WAVE HAS SINCE LIFTED OFF TO THE NORTHEAST OF THE AREA.
HOWEVER...ANOTHER WAVE IS NOW LIFTING TO THE NORTH ACROSS THE I-25
CORRIDOR. NORTH WINDS HAVE DECREASED SOME ACROSS THE PLAINS...BUT
THERE HAVE STILL BEEN SOME INTERMITTENT GUSTS TO AROUND 40 MPH. AS
THE LATE AFTERNOON AND EVENING PROGRESSES...EXPECT THAT THESE WINDS
WILL CONTINUE TO COME DOWN...AND ALTHOUGH THERE WILL STILL BE A
BRIEF WINDOW OF SNOW AND BLOWING SNOW...THINK THAT IMPACTS WON`T BE
AS HIGH AS THE BLIZZARD CONDITIONS WE SAW BRIEFLY EARLIER. THUS
HAVE DOWNGRADED THE BLIZZARD WARNINGS TO WINTER WEATHER ADVISORIES.
SNOWFALL FOR THE SOUTHEAST MOUNTAINS HAS ALSO COME UP SHY...AND WITH
BEST ISENTROPIC UPGLIDE PUSHING OFF TO THE NORTHEAST OF THE AREA
LATE THIS AFTERNOON AND EVENING...THINK THAT THE WINDOW FOR HEAVIER
SNOWFALL AMOUNTS IS CLOSING. STILL THINK A GOOD 4 TO 8 INCHES MAY
BE REALIZED...SO DOWNGRADED THE SOUTHEAST MOUNTAINS TO A WINTER
WEATHER ADVISORY AS WELL. TELLER COUNTY MAY END UP COMING UP SHORT
ON THESE AMOUNTS. ADVISORIES ARE SET TO EXPIRE AROUND 6 PM FOR MOST
AREAS...THOUGH DID HANG ON TO THEM A LITTLE LONGER FOR THE
WETS...NORTHERN SANGRES...AND THE UPPER ARKANSAS RIVER VALLEY OF
FREMONT AND CHAFFEE COUNTIES WHERE THE RUC13 CONTINUES TO KEEP SOME
SNOW GOING THROUGH THEN.
AREAS DOING THE BEST FROM THIS STORM APPEAR TO BE ACROSS THE
SOUTHWEST AND CENTRAL MOUNTAINS WHERE SNOW SHOWERS HAVE BECOME MORE
CONVECTIVE IN NATURE THIS AFTERNOON. KALS HAS SEEN BRIEFLY POOR VIS IN HEAVY
SNOW FROM A THUNDER SNOW SHOWER EARLIER THIS AFTERNOON. IN
FACT...IN AND AROUND NATHROP AND SALIDA HAVE PICKED UP ON THE
ORDER OF 5 TO 6.5 INCHES OF SNOW. THIS IS WHERE THE UPPER LEVEL
DIFFLUENCE HAS BEEN BEST...ESPECIALLY THIS MORNING. HAVE EXTENDED
THE ADVISORIES AND WARNINGS ACROSS THE SOUTHWEST AND CENTRAL
MOUNTAINS THROUGH 03Z TO ACCOUNT FOR SOME RESIDUAL LIFT AND
INSTABILITY THROUGH THE EVENING. AFTER 03Z...THINK SNOWFALL RATES
WILL DECREASE QUICKLY. OVERALL ANOTHER 1 TO 4 INCHES CAN BE
EXPECTED ACROSS THE HIGHER ELEVATIONS THROUGH THAT TIME.
FOR TONIGHT...COLD OVERNIGHT LOWS EXPECTED...THOUGH RESIDUAL CLOUD
COVER WILL KEEP THEM FROM PLUMMETING AS FAR AS THEY POTENTIALLY
COULD GIVEN THE COLD AIR MASS IN PLACE. LOWS SHOULD DROP INTO THE
TEENS FOR MOST AREAS...WITH SINGLE DIGITS ACROSS SOME OF THE MOUNTAIN
AREAS.
UPPER LOW WILL SLOWLY LIFT OFF TO THE NORTHEAST ON WEDNESDAY...THOUGH WITH
RESIDUAL MOISTURE AND INSTABILITY OVER THE REGION...HAVE MAINTAINED
SOME ISOLATED TO SCATTERED SNOW SHOWERS...MAINLY OVER AND NEAR THE
MOUNTAINS. TEMPERATURES WILL REMAIN BELOW NORMAL...WITH HIGHS ONLY
TOPPING OUT IN THE 30S TO LOWER 40S FOR THE LOWER ELEVATIONS WITH
20S AND 30S FOR THE MOUNTAIN AREAS. -KT
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 320 PM MDT TUE APR 9 2013
WEDNESDAY NIGHT THROUGH FRIDAY...ONE UPPER LOW PRES SYSTEM IS
FORECAST TO BE EXITING THE REGION WED NIGHT...WITH ONLY A BRIEF
BREAK IN PCPN FOR THE HIGHER TERRAIN BEFORE ANOTHER UPPER
DISTURBANCE ROLLS IN. THE NEXT WAVE IS EXPECTED TO TRACK ACROSS THE
GREAT BASIN AND N ROCKIES THU THROUGH FRI MORNING...BRINGING
SCATTERED SNOW SHOWERS TO THE MTS THU AND FRI...AND A RAIN SNOW MIX
FOR THE ADJACENT PLAINS THU NIGHT THROUGH FRI MORNING. TEMPS ARE
EXPECTED TO WARM A BIT WITH MAX TEMPS IN THE 50S THU AND FRI...BUT
MIN TEMPS STILL IN THE 20S TO AROUND 30 F BOTH NIGHTS.
SATURDAY AND SUNDAY...THE GFS AND ECMWF MODELS INDICATE THAT A BROAD
LOW PRESSURE AREA WILL GRADUALLY TRACK EAST ALONG THE US CANADA
BORDER OVER THE WEEKEND...PRODUCING BRISK WESTERLY FLOW ACROSS
COLORADO WITH A LINGERING THREAT OF PCPN FOR MAINLY THE NORTHERN
HALF OF THE STATE. THIS WILL LEAK ISOLATED SHOWERS DOWN INTO THE
CENTRAL MTS ON SAT...THEN THE CONTDVD AND PALMER DVD FOR SUN. THE
WESTERLY FLOW SHOULD HELP BOOST MAX TEMPS BOTH DAYS INTO THE 60S TO
NEAR 70 F FOR THE E PLAINS.
MONDAY AND TUESDAY...THE UPPER LOW GATHERS STRENGTH AND DROPS SOUTH
OUT OF THE PAC NW EARLY MON MORNING...THEN SAGS TO THE SW ACROSS THE
GREAT BASIN LATE MON. SW FLOW ALOFT INCREASES ACROSS THE 4 CORNERS
ON MON...DRAWING IN MOISTURE TO THE HIGHER TERRAIN FOR MON AND THEN
SPREADING ACROSS MUCH OF THE FORECAST AREA FOR TUE. EARLY YET O
COURSE...BUT THIS SYSTEM LOOKS TO BE THE STRONGER FEATURE FOR THE
EXTENDED PERIOD. MOORE
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1135 PM MDT TUE APR 9 2013
KCOS SHOULD HAVE VFR CONDITIONS TONIGHT ALTHOUGH WITH SOME LOW
CLOUDS IN THE VCNTY THERE COULD BE SOME BRIEF MVFR CONDITIONS
THROUGH ABOUT 10Z. EXPECT VFR CONDITIONS AT KCOS ON WED. KPUB
SHOULD GENERALLY HAVE VFR CONDITIONS TONIGHT AND WEDNESDAY...ALTHOUGH
THERE COULD BE SOME BRIEF MVFR CONDITIONS THROUGH ABOUT 10Z. KALS
WILL HAVE THE POTENTIAL FOR SOME SNOW SHOWERS IN THE AREA THROUGH
LATE MORNING WED. MVFR CONDITIONS ARE EXPECTED THROUGH ABOUT 10Z
OR POSSIBLY AT LITTLE LATER...BUT IF SNOW SHOWERS MOVE OVR THE
AREA BRIEF IFR CONDITIONS WL LIKELY OCCUR. BY WED AFTERNOON...
CHANCES FOR PCPN AT KALS WL DECREASE AND CONDITIONS SHOULD BE VFR.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...28
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...28
AREA FORECAST DISCUSSION
NWS NEW YORK NY
224 PM EDT WED APR 10 2013
.SYNOPSIS...
WAVES OF WEAK LOW PRESSURE WILL RIDE ALONG A FRONTAL BOUNDARY
THAT REMAINS ACROSS THE REGION THROUGH TONIGHT. THE FRONT WILL
SAG SOUTH THROUGH OUR AREA AS A BACK DOOR COLD FRONT EARLY THURSDAY.
A LOW PRESSURE SYSTEM WILL MOVE THROUGH ON FRIDAY...FOLLOWED BY
BUILDING HIGH PRESSURE THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
INCREASING SE FLOW THIS AFTERNOON IN RESPONSE TO WEAK LOW PRESSURE
APPROACHING FROM PA AND SEA BREEZE VIA DIFFERENTIAL HEATING. AS
THE SE FLOW COMMENCES...TEMPS SHOULD FALL LATE THIS AFTERNOON.
TEMPS ARE BASED ON NAM AND RAP 2M TEMPS WHICH SUPPORT UPPER 70S FOR
THE NY METRO AND AROUND 80 OVER NE NJ DESPITE CLOUD COVER BEFORE THE
SE FLOW WORKS IN.
HEATING AND SE WIND SHIFT SHOULD ALLOW FOR SCT LATE DAY CONVECTION
TO DEVELOP OVER N JERSEY. 0-6 KM BULK SHEAR SUGGESTS MARGINAL SEVERE
POTENTIAL...BUT INSTABILITY IS IN QUESTION. SPC HAS BROUGHT EDGE OF
SLIGHT RISK AREA TO NYC...SO HAVE RETURNED MENTION TO HWO. WILL NEED
TO MONITOR THE SITUATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
ANOTHER WEAK LOW PASSES THROUGH THE REGION TONIGHT WITH A HIGH
DEGREE OF UNCERTAINTY ON THE SENSIBLE WX. HAVE SUGGESTED THE MAIN
PCPN CHANCE IS NORTH...BASED ON ECMWF AND GFS...BUT HAVE VERY LOW
CONFIDENCE IN THIS.
TEMPS OVERNIGHT ARE BLENDED MOS IN THE 45 TO 50 RANGE.
THE COOL MARITIME AIR REALLY COMES IN ON THURSDAY IN THE WAKE OF
THE BACKDOOR COLD FRONT WITH NEARLY STEADY TEMPS. HAVE HIGHS IN
THE LOWER TO MID 50S...WHICH MAY STILL BE TOO HIGH. ONSHORE FLOW
WITH OVER-RUNNING SETTING UP IN THE AFTERNOON SUGGEST AT LEAST
THE CHC FOR LIGHT RAIN OR DRIZZLE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT TO OUR SOUTH TRIES TO NUDGE NORTH THURSDAY NIGHT AS THE
PARENT LOW PRESSURE SYSTEM TO THE WEST MOVES EAST. MOISTURE IS NOT
DEEP...SO EXPECTING LIGHT RAIN AND DRIZZLE TO BECOME LIKELY AS THE
NIGHT PROGRESSES.
MODELS CONTINUE TO SHOW A SECONDARY LOW FORMING...THEN PASSING OVER
OR JUST SOUTH OF THE TRI-STATE AREA LATE-DAY FRIDAY OR FRIDAY NIGHT.
STILL SOME UNCERTAINTY REGARDING THE NATURE OF THE RAINFALL BEING
MORE STRATIFORM OR CONVECTIVE...HOWEVER THERE IS GOOD CONFIDENCE IN
THE OCCURRENCE OF RAIN ON FRIDAY WITH FORCING FROM THE LOW AND THE
PRECEDING LOW LEVEL JET. KEPT ANY MENTION OF THUNDER AS
ISOLATED FOR NOW...WITH BEST CHANCES ACROSS THE SOUTHERN
SECTIONS...SINCE THIS AREA WOULD MORE LIKELY BE WARM-SECTORED.
GREATEST IMPACT POTENTIAL FROM THIS STORM WOULD BE MINOR FLOODING
DUE TO HEAVY DOWNPOURS IN ANY CONVECTION. SEE THE HYDROLOGY SECTION
BELOW FOR MORE DETAILS. OTHERWISE...THERE COULD BE A BRIEF PERIOD OF
STRONG WINDS (OUTSIDE OF ANY THUNDERSTORMS) PRIMARILY EAST OF THE
CITY FRIDAY AFTERNOON. COASTAL FLOODING DOESN`T SEEM TO BE A GREAT
CONCERN AT THIS TIME AS THE MOST SUSCEPTIBLE HIGH TIDE
CYCLE...FRIDAY MORNING`S...IS THE LOWER OF THE TWO DAILY HIGH TIDES.
RAIN CHANCES THEN TAPER OFF DURING FRIDAY EVENING WITH THE STORM
HEADING OUT TO SEA. HIGH PRESSURE THEN BUILDS IN WITH DRY WEATHER
FOR SATURDAY. THERE COULD THEN BE A SHOWER SATURDAY NIGHT WITH A
SHORTWAVE PASSING THROUGH. RIDGING AT THE SURFACE AND ALOFT THEN
KEEPS US DRY ON SUNDAY...AND LIKELY EXTENDS THROUGH MONDAY. MOISTURE
RIDING ALONG A FRONTAL BOUNDARY TO OUR WEST COULD REACH HERE AND
BRING A SHOWER IN SPOTS MONDAY NIGHT AND TUESDAY.
HIGH TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL FOR MOST SPOTS ON
FRIDAY...THEN SLIGHTLY ABOVE NORMAL ON SATURDAY...RETURNING TO NEAR
NORMAL ON SUNDAY. HIGHS THEN MODERATE ABOVE NORMAL MONDAY AND
TUESDAY.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
A FRONTAL BOUNDARY REMAINS IN THE VICINITY WITH WEAK WAVES OF LOW
PRESSURE RIDING ALONG IT INTO THIS EVENING. THE FRONT MOVES
SLIGHTLY SOUTH TONIGHT INTO THURSDAY AS WEAK HIGH PRESSURE BUILDS
IN FROM THE NORTH AND WEST.
VFR WITH EXCEPTION OF KSWF WHERE MVFR IS OCCURRING. CONDITIONS
DETERIORATE WITH ONSET OF TSRA 23-03Z. MVFR TO LOCALIZED IFR WILL
BE POSSIBLE AS WELL AS GUSTY WINDS OF 30 KT. GUSTS COULD BE
POSSIBLY HIGHER. TIMING OF TSRA COULD VARY BY 1-2 HOURS.
SE-S WINDS BECOME MORE NORTHERLY TONIGHT AND BACK EASTERLY ON
THURSDAY. WIND SPEED AROUND 10 KT OR LESS. MVFR CONDITIONS WILL
PERSIST WITH IFR POSSIBLE AT TIMES ON THURSDAY IN LIGHT
RAIN/DRIZZLE.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: AMENDMENTS ARE LIKELY TO REFINE TIMING OF
TSRA. START/END TIME COULD VARY BY 1-2 HOURS.
KLGA FCSTER COMMENTS: AMENDMENTS ARE LIKELY TO REFINE TIMING OF
TSRA. START/END TIME COULD VARY BY 1-2 HOURS.
KEWR FCSTER COMMENTS: AMENDMENTS ARE LIKELY TO REFINE TIMING OF
TSRA. START/END TIME COULD VARY BY 1-2 HOURS.
KTEB FCSTER COMMENTS: AMENDMENTS ARE LIKELY TO REFINE TIMING OF
TSRA. START/END TIME COULD VARY BY 1-2 HOURS.
KHPN FCSTER COMMENTS: AMENDMENTS ARE LIKELY TO REFINE TIMING OF
TSRA. START/END TIME COULD VARY BY 1-2 HOURS.
KISP FCSTER COMMENTS: AMENDMENTS ARE LIKELY TO REFINE TIMING OF
TSRA. START/END TIME COULD VARY BY 1-2 HOURS.
.OUTLOOK FOR 18Z THURSDAY THROUGH MONDAY...
.THU-THU EVENING...MVFR POSSIBLE IN LIGHT RAIN OR DRIZZLE. E
WINDS 10-15G20-25KT THU EVENING.
.LATE THU NGT AND FRI...WIDESPREAD IFR IN RAIN. E WINDS
15-25G30-40KT POSSIBLE THU NIGHT INTO FRIDAY MORNING...BECOMING NE
10-15G20-25KT IN THE AFTERNOON. LLWS AND COMPRESSION LIKELY.
.FRIDAY NIGHT...BECOMING VFR FROM W TO E.
.SATURDAY-SATURDAY NIGHT...VFR.
.SUNDAY...VFR. W-NW WIND 10-15G20-25 KT.
.SUNDAY NIGHT...VFR.
.MONDAY...VFR. S WINDS 10-15 KT GUSTS 20 KT.
&&
.MARINE...
QUIET WINDS/SEAS THROUGH TONIGHT AS A SERIES OF WEAK FRONTAL
WAVES MOVE ACROSS...WITH POSSIBLE TSTMS MAINLY FOR THE WATERS
SURROUNDING NYC LATE TODAY INTO THIS EVENING. LOW LEVEL MOISTURE
INCREASES BEFORE A BACK DOOR COLD FRONTAL PASSAGE LATE.
STRENGTHENING EASTERLY FLOW IN THE WAKE OF A BACK DOOR COLD FRONT.
SCA CONDITIONS LIKELY THURSDAY NIGHT AND FRIDAY WITH LOW PRESSURE
PASSING THROUGH. THERE IS A CHANCE OF DENSE FOG DEVELOPMENT THROUGH
FRIDAY MORNING AS WELL. BY FRIDAY NIGHT...WINDS SUBSIDE...HOWEVER
SEAS ON THE OCEAN WILL REMAIN AT SCA LEVELS THROUGH AT LEAST THE
DAYTIME ON SATURDAY. SUB-SCA CONDITIONS SHOULD RETURN BY SUNDAY
MORNING.
&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...JC
AVIATION...JM
MARINE...JC/TONGUE
HYDROLOGY...JC/TONGUE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1203 PM EDT WED APR 10 2013
.SYNOPSIS...
WAVES OF WEAK LOW PRESSURE WILL RIDE ALONG A FRONTAL BOUNDARY
THAT REMAINS ACROSS THE REGION THROUGH TONIGHT. THE FRONT WILL
SAG SOUTH THROUGH OUR AREA AS A BACK DOOR COLD FRONT EARLY
THURSDAY. A LOW PRESSURE SYSTEM WILL MOVE THROUGH ON FRIDAY...
FOLLOWED BY BUILDING HIGH PRESSURE THIS WEEKEND INTO EARLY
NEXT WEEK.
&&
.NEAR TERM /UNTIL 10 PM THIS EVENING/...
LIGHT N-NE FLOW SHOULD VEER TO AN INCREASING SE FLOW THIS
AFTERNOON IN RESPONSE TO WEAK LOW PRESSURE APPROACHING FROM PA AND
SEA BREEZE VIA DIFFERENTIAL HEATING. AS THE SE FLOW
COMMENCES...TEMPS SHOULD FALL LATE THIS AFTERNOON.
TEMPS ARE BASED ON NAM AND RAP 2M TEMPS WHICH SUPPORT UPPER 70S FOR
THE NY METRO AND LOWER 80S OVER NE NJ DESPITE CLOUD COVER BEFORE
THE SE FLOW WORKS IN.
HEATING AND SE WIND SHIFT SHOULD ALLOW FOR SCT LATE DAY CONVECTION
TO DEVELOP OVER N JERSEY. 0-6 KM BULK SHEAR SUGGESTS MARGINAL SEVERE
POTENTIAL...BUT INSTABILITY IS IN QUESTION. SPC HAS BROUGHT EDGE OF
SLIGHT RISK AREA TO NYC...SO HAVE RETURNED MENTION TO HWO. HI-RES
MODELS SUGGEST ACTIVITY COULD REACH THE CWA AS EARLY AS LATE
AFTERNOON...AND MORE LIKELY THIS EVENING IN THE FORM OF A LINE OR
CLUSTER APPROACHING FROM THE NW. ELEVATED MIXED LAYER UP T0 700 MB
MAY ACT TO MAINTAIN CONVECTION FROM NYC EAST DESPITE MARINE
LAYER...WILL NEED TO MONITOR THE SITUATION.
&&
.SHORT TERM /10 PM THIS EVENING THROUGH 6 PM THURSDAY/...
ANOTHER WEAK LOW PASSES THROUGH THE REGION LATER TONIGHT WITH A
HIGH DEGREE OF UNCERTAINTY ON THE SENSIBLE WX. HAVE SUGGESTED THE
MAIN PCPN CHANCE IS NORTH...BASED ON ECMWF AND GFS...BUT HAVE VERY
LOW CONFIDENCE IN THIS.
TEMPS OVERNIGHT ARE BLENDED MOS IN THE 45 TO 50 RANGE.
THE COOL MARITIME AIR REALLY COMES IN ON THURSDAY IN THE WAKE OF
THE BACKDOOR COLD FRONT WITH NEARLY STEADY TEMPS. HAVE HIGHS IN
THE LOWER TO MID 50S...WHICH MAY STILL BE TOO HIGH. ONSHORE FLOW
WITH OVER-RUNNING SETTING UP IN THE AFTERNOON SUGGEST AT LEAST
THE CHC FOR LIGHT RAIN OR DRIZZLE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT TO OUR SOUTH TRIES TO NUDGE NORTH THURSDAY NIGHT AS THE
PARENT LOW PRESSURE SYSTEM TO THE WEST MOVES EAST. MOISTURE IS NOT
DEEP...SO EXPECTING LIGHT RAIN AND DRIZZLE TO BECOME LIKELY AS THE
NIGHT PROGRESSES.
MODELS CONTINUE TO SHOW A SECONDARY LOW FORMING...THEN PASSING OVER
OR JUST SOUTH OF THE TRI-STATE AREA LATE-DAY FRIDAY OR FRIDAY NIGHT.
STILL SOME UNCERTAINTY REGARDING THE NATURE OF THE RAINFALL BEING
MORE STRATIFORM OR CONVECTIVE...HOWEVER THERE IS GOOD CONFIDENCE IN
THE OCCURRENCE OF RAIN ON FRIDAY WITH FORCING FROM THE LOW AND THE
PRECEDING LOW LEVEL JET. KEPT ANY MENTION OF THUNDER AS
ISOLATED FOR NOW...WITH BEST CHANCES ACROSS THE SOUTHERN
SECTIONS...SINCE THIS AREA WOULD MORE LIKELY BE WARM-SECTORED.
GREATEST IMPACT POTENTIAL FROM THIS STORM WOULD BE MINOR FLOODING
DUE TO HEAVY DOWNPOURS IN ANY CONVECTION. SEE THE HYDROLOGY SECTION
BELOW FOR MORE DETAILS. OTHERWISE...THERE COULD BE A BRIEF PERIOD OF
STRONG WINDS (OUTSIDE OF ANY THUNDERSTORMS) PRIMARILY EAST OF THE
CITY FRIDAY AFTERNOON. COASTAL FLOODING DOESN`T SEEM TO BE A GREAT
CONCERN AT THIS TIME AS THE MOST SUSCEPTIBLE HIGH TIDE
CYCLE...FRIDAY MORNING`S...IS THE LOWER OF THE TWO DAILY HIGH TIDES.
RAIN CHANCES THEN TAPER OFF DURING FRIDAY EVENING WITH THE STORM
HEADING OUT TO SEA. HIGH PRESSURE THEN BUILDS IN WITH DRY WEATHER
FOR SATURDAY. THERE COULD THEN BE A SHOWER SATURDAY NIGHT WITH A
SHORTWAVE PASSING THROUGH. RIDGING AT THE SURFACE AND ALOFT THEN
KEEPS US DRY ON SUNDAY...AND LIKELY EXTENDS THROUGH MONDAY. MOISTURE
RIDING ALONG A FRONTAL BOUNDARY TO OUR WEST COULD REACH HERE AND
BRING A SHOWER IN SPOTS MONDAY NIGHT AND TUESDAY.
HIGH TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL FOR MOST SPOTS ON
FRIDAY...THEN SLIGHTLY ABOVE NORMAL ON SATURDAY...RETURNING TO NEAR
NORMAL ON SUNDAY. HIGHS THEN MODERATE ABOVE NORMAL MONDAY AND
TUESDAY.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
A FRONTAL BOUNDARY REMAINS IN THE VICINITY WITH WEAK WAVES OF LOW
PRESSURE RIDING ALONG IT THROUGH EARLY THIS MORNING AND THEN AGAIN
THIS EVENING.
VFR THROUGH AT LEAST MIDDAY TODAY. MVFR POSSIBLE THIS EVENING IN
SCT SHRA - REFLECT WITH TEMPO IN TAFS WITH MOST LIKELY TIME FRAME
AT THIS TIME. ISOLD TSRA ALSO POSSIBLE THIS EVENING - BUT
CONFIDENCE IN TIMING/EXACT LOCATIONS TOO LOW TO REFLECT IN TAFS AT
THIS TIME. GUSTY WINDS IN THE STRONGER CONVECTION IS POSSIBLE.
THE FRONTAL BOUNDARY IN THE VICINITY MAKES WIND FORECAST VERY
TRICKY AND OF VERY LOW CONFIDENCE. POSSIBLE SEA BREEZE FOR
KJFK...KBDR...AND KGON. POSSIBLE SOUND BREEZE FOR KLGA ALLOWING
WINDS TO SHIFT TO THE NORTHEAST IN THE AFTERNOON.
NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE IF SEA BREEZE DEVELOPS
LATER TODAY. LIGHT WINDS WITH LOW CONFIDENCE IN WIND DIRECTION.
SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KLGA FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KEWR FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KHPN FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KISP FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
.OUTLOOK FOR 03Z THURSDAY THROUGH SUNDAY...
.TONIGHT...SHRA WITH ISOLD TSRA IN THE EVENING. MVFR LIKELY WITH
IFR POSSIBLE IN -RA/DZ LATE WEDNESDAY NIGHT.
.THU-THU EVENING...MVFR POSSIBLE IN LIGHT RAIN OR DRIZZLE. E
WINDS 10-15G20-25KT THU EVENING.
.LATE THU NGT AND FRI...WIDESPREAD IFR IN RAIN. E WINDS
15-25G30-40KT POSSIBLE THU NIGHT INTO FRIDAY MORNING...BECOMING NE
10-15G20-25KT IN THE AFTERNOON. LLWS AND COMPRESSION LIKELY.
.FRIDAY NIGHT...BECOMING VFR FROM W TO E.
.SATURDAY...VFR.
.SATURDAY NIGHT-SUNDAY...VFR. W-NW WIND 10-15G20-25 KT POSSIBLE.
&&
.MARINE...
QUIET WINDS/SEAS THROUGH TONIGHT AS A SERIES OF WEAK FRONTAL
WAVES MOVE ACROSS...WITH POSSIBLE TSTMS MAINLY FOR THE WATERS
SURROUNDING NYC LATE TODAY INTO THIS EVENING. LOW LEVEL MOISTURE
INCREASES BEFORE A BACK DOOR COLD FRONTAL PASSAGE LATE.
STRENGTHENING EASTERLY FLOW IN THE WAKE OF A BACK DOOR COLD FRONT.
SCA CONDITIONS LIKELY THURSDAY NIGHT AND FRIDAY WITH LOW PRESSURE
PASSING THROUGH. THERE IS A CHANCE OF DENSE FOG DEVELOPMENT THROUGH
FRIDAY MORNING AS WELL. BY FRIDAY NIGHT...WINDS SUBSIDE...HOWEVER
SEAS ON THE OCEAN WILL REMAIN AT SCA LEVELS THROUGH AT LEAST THE
DAYTIME ON SATURDAY. SUB-SCA CONDITIONS SHOULD RETURN BY SUNDAY
MORNING.
&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/TONGUE
NEAR TERM...GOODMAN/TONGUE
SHORT TERM...GOODMAN/TONGUE
LONG TERM...JC
AVIATION...JM/JP
MARINE...JC/TONGUE
HYDROLOGY...JC/TONGUE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
925 AM EDT WED APR 10 2013
.SYNOPSIS...
WAVES OF WEAK LOW PRESSURE WILL RIDE ALONG A FRONTAL BOUNDARY
THAT REMAINS ACROSS THE REGION THROUGH TONIGHT. THE FRONT WILL
SAG SOUTH THROUGH OUR AREA AS A BACK DOOR COLD FRONT EARLY THURSDAY.
A LOW PRESSURE SYSTEM WILL MOVE THROUGH ON FRIDAY...FOLLOWED BY
BUILDING HIGH PRESSURE THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LIGHT N-NE FLOW THIS MORNING SHOULD VEER TO AN INCREASING SE FLOW IN
RESPONSE TO WEAK LOW PRESSURE APPROACHING FROM PA AND SEA BREEZE VIA
DIFFERENTIAL HEATING. AS THE SE FLOW COMMENCES...TEMPS SHOULD FALL
LATE THIS AFTERNOON.
TEMPS ARE BASED ON NAM AND RAP 2M TEMPS WHICH SUPPORT UPPER 70S FOR
THE NY METRO AND AROUND 80 OVER NE NJ DESPITE CLOUD COVER BEFORE THE
SE FLOW WORKS IN.
HEATING AND SE WIND SHIFT SHOULD ALLOW FOR SCT LATE DAY CONVECTION
TO DEVELOP OVER N JERSEY. 0-6 KM BULK SHEAR SUGGESTS MARGINAL SEVERE
POTENTIAL...BUT INSTABILITY IS IN QUESTION. SPC HAS BROUGHT EDGE OF
SLIGHT RISK AREA TO NYC...SO HAVE RETURNED MENTION TO HWO. WILL NEED
TO MONITOR THE SITUATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
ANOTHER WEAK LOW PASSES THROUGH THE REGION TONIGHT WITH A HIGH
DEGREE OF UNCERTAINTY ON THE SENSIBLE WX. HAVE SUGGESTED THE MAIN
PCPN CHANCE IS NORTH...BASED ON ECMWF AND GFS...BUT HAVE VERY LOW
CONFIDENCE IN THIS.
TEMPS OVERNIGHT ARE BLENDED MOS IN THE 45 TO 50 RANGE.
THE COOL MARITIME AIR REALLY COMES IN ON THURSDAY IN THE WAKE OF
THE BACKDOOR COLD FRONT WITH NEARLY STEADY TEMPS. HAVE HIGHS IN
THE LOWER TO MID 50S...WHICH MAY STILL BE TOO HIGH. ONSHORE FLOW
WITH OVER-RUNNING SETTING UP IN THE AFTERNOON SUGGEST AT LEAST
THE CHC FOR LIGHT RAIN OR DRIZZLE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT TO OUR SOUTH TRIES TO NUDGE NORTH THURSDAY NIGHT AS THE
PARENT LOW PRESSURE SYSTEM TO THE WEST MOVES EAST. MOISTURE IS NOT
DEEP...SO EXPECTING LIGHT RAIN AND DRIZZLE TO BECOME LIKELY AS THE
NIGHT PROGRESSES.
MODELS CONTINUE TO SHOW A SECONDARY LOW FORMING...THEN PASSING OVER
OR JUST SOUTH OF THE TRI-STATE AREA LATE-DAY FRIDAY OR FRIDAY NIGHT.
STILL SOME UNCERTAINTY REGARDING THE NATURE OF THE RAINFALL BEING
MORE STRATIFORM OR CONVECTIVE...HOWEVER THERE IS GOOD CONFIDENCE IN
THE OCCURRENCE OF RAIN ON FRIDAY WITH FORCING FROM THE LOW AND THE
PRECEDING LOW LEVEL JET. KEPT ANY MENTION OF THUNDER AS
ISOLATED FOR NOW...WITH BEST CHANCES ACROSS THE SOUTHERN
SECTIONS...SINCE THIS AREA WOULD MORE LIKELY BE WARM-SECTORED.
GREATEST IMPACT POTENTIAL FROM THIS STORM WOULD BE MINOR FLOODING
DUE TO HEAVY DOWNPOURS IN ANY CONVECTION. SEE THE HYDROLOGY SECTION
BELOW FOR MORE DETAILS. OTHERWISE...THERE COULD BE A BRIEF PERIOD OF
STRONG WINDS (OUTSIDE OF ANY THUNDERSTORMS) PRIMARILY EAST OF THE
CITY FRIDAY AFTERNOON. COASTAL FLOODING DOESN`T SEEM TO BE A GREAT
CONCERN AT THIS TIME AS THE MOST SUSCEPTIBLE HIGH TIDE
CYCLE...FRIDAY MORNING`S...IS THE LOWER OF THE TWO DAILY HIGH TIDES.
RAIN CHANCES THEN TAPER OFF DURING FRIDAY EVENING WITH THE STORM
HEADING OUT TO SEA. HIGH PRESSURE THEN BUILDS IN WITH DRY WEATHER
FOR SATURDAY. THERE COULD THEN BE A SHOWER SATURDAY NIGHT WITH A
SHORTWAVE PASSING THROUGH. RIDGING AT THE SURFACE AND ALOFT THEN
KEEPS US DRY ON SUNDAY...AND LIKELY EXTENDS THROUGH MONDAY. MOISTURE
RIDING ALONG A FRONTAL BOUNDARY TO OUR WEST COULD REACH HERE AND
BRING A SHOWER IN SPOTS MONDAY NIGHT AND TUESDAY.
HIGH TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL FOR MOST SPOTS ON
FRIDAY...THEN SLIGHTLY ABOVE NORMAL ON SATURDAY...RETURNING TO NEAR
NORMAL ON SUNDAY. HIGHS THEN MODERATE ABOVE NORMAL MONDAY AND
TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A FRONTAL BOUNDARY REMAINS IN THE VICINITY WITH WEAK WAVES OF LOW
PRESSURE RIDING ALONG IT THROUGH EARLY THIS MORNING AND THEN AGAIN
THIS EVENING.
VFR THROUGH AT LEAST MIDDAY TODAY. MVFR POSSIBLE THIS EVENING IN
SCT SHRA - REFLECT WITH TEMPO IN TAFS WITH MOST LIKELY TIME FRAME
AT THIS TIME. ISOLD TSRA ALSO POSSIBLE THIS EVENING - BUT
CONFIDENCE IN TIMING/EXACT LOCATIONS TOO LOW TO REFLECT IN TAFS AT
THIS TIME. GUSTY WINDS IN THE STRONGER CONVECTION IS POSSIBLE.
THE FRONTAL BOUNDARY IN THE VICINITY MAKES WIND FORECAST VERY
TRICKY AND OF VERY LOW CONFIDENCE. POSSIBLE SEABREEZE FOR
KJFK...KBDR...AND KGON. POSSIBLE SOUND BREEZE FOR KLGA ALLOWING
WINDS TO SHIFT TO THE NORTHEAST IN THE AFTERNOON.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE IF SEA BREEZE DEVELOPS
LATER TODAY. LIGHT WINDS WITH LOW CONFIDENCE IN WIND DIRECTION.
SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KLGA FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KEWR FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KHPN FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KISP FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
.OUTLOOK FOR 03Z THURSDAY THROUGH SUNDAY...
.TONIGHT...SHRA WITH ISOLD TSRA IN THE EVENING. MVFR LIKELY WITH
IFR POSSIBLE IN -RA/DZ LATE WEDNESDAY NIGHT.
.THU-THU EVENING...MVFR POSSIBLE IN LIGHT RAIN OR DRIZZLE. E
WINDS 10-15G20-25KT THU EVENING.
.LATE THU NGT AND FRI...WIDESPREAD IFR IN RAIN. E WINDS
15-25G30-40KT POSSIBLE THU NIGHT INTO FRIDAY MORNING...BECOMING NE
10-15G20-25KT IN THE AFTERNOON. LLWS AND COMPRESSION LIKELY.
.FRIDAY NIGHT...BECOMING VFR FROM W TO E.
.SATURDAY...VFR.
.SATURDAY NIGHT-SUNDAY...VFR. W-NW WIND 10-15G20-25 KT POSSIBLE.
&&
.MARINE...
QUIET WINDS/SEAS THROUGH TONIGHT AS A SERIES OF WEAK FRONTAL
WAVES MOVE ACROSS...WITH POSSIBLE TSTMS MAINLY FOR THE WATERS
SURROUNDING NYC LATE TODAY INTO THIS EVENING. LOW LEVEL MOISTURE
INCREASES BEFORE A BACK DOOR COLD FRONTAL PASSAGE LATE.
STRENGTHENING EASTERLY FLOW IN THE WAKE OF A BACK DOOR COLD FRONT.
SCA CONDITIONS LIKELY THURSDAY NIGHT AND FRIDAY WITH LOW PRESSURE
PASSING THROUGH. THERE IS A CHANCE OF DENSE FOG DEVELOPMENT THROUGH
FRIDAY MORNING AS WELL. BY FRIDAY NIGHT...WINDS SUBSIDE...HOWEVER
SEAS ON THE OCEAN WILL REMAIN AT SCA LEVELS THROUGH AT LEAST THE
DAYTIME ON SATURDAY. SUB-SCA CONDITIONS SHOULD RETURN BY SUNDAY
MORNING.
&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...JC
AVIATION...JP
MARINE...JC/TONGUE
HYDROLOGY...JC/TONGUE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
748 AM EDT WED APR 10 2013
.SYNOPSIS...
WAVES OF WEAK LOW PRESSURE WILL RIDE ALONG A FRONTAL BOUNDARY
THAT REMAINS ACROSS THE REGION THROUGH TONIGHT. THE FRONT WILL
SAG SOUTH THROUGH OUR AREA AS A BACK DOOR COLD FRONT EARLY THURSDAY.
A LOW PRESSURE SYSTEM WILL MOVE THROUGH ON FRIDAY...FOLLOWED BY
BUILDING HIGH PRESSURE THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
EXPECT TO STAY IN A LIGHT NORTHERLY FLOW THIS MORNING...THEN TURN
AROUND TO AN INCREASING SOUTHEASTERLY FLOW. THIS WILL RESULT IN
FALLING TEMPS THIS AFTERNOON. THE SOUTHEAST FLOW IN RESPONSE TO
WEAK LOW PRESSURE OVER PA AND DIFFERENTIAL HEAT - SEA BREEZE.
TEMPS ARE BASED ON NAM AND RAP 2 METER TEMPS WHICH SUPPORT UPPER
70S FOR THE NY METRO AND AROUND 80 OVER NE NJ DESPITE CLOUD COVER
BEFORE THE SE FLOW WORKS IN.
HEATING AND SE WIND SHIFT SHOULD ALLOW FOR SCT LATE DAY CONVECTION
TO DEVELOP OVER N JERSEY. 0-6 KM BULK SHEAR SUGGESTS MARGINAL
SEVERE POTENTIAL...BUT INSTABILITY IS IN QUESTION. SPC HAS DROPPED
THE SLIGHT RISK FOR N JERSEY...WHICH I AGREE WITH...BUT WE`LL NEED TO
MONITOR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
ANOTHER WEAK LOW PASSES THROUGH THE REGION TONIGHT WITH A HIGH
DEGREE OF UNCERTAINTY ON THE SENSIBLE WX. HAVE SUGGESTED THE MAIN
PCPN CHANCE IS NORTH...BASED ON ECMWF AND GFS...BUT HAVE VERY LOW
CONFIDENCE IN THIS.
TEMPS OVERNIGHT ARE BLENDED MOS IN THE 45 TO 50 RANGE.
THE COOL MARITIME AIR REALLY COMES IN ON THURSDAY IN THE WAKE OF
THE BACKDOOR COLD FRONT WITH NEARLY STEADY TEMPS. HAVE HIGHS IN
THE LOWER TO MID 50S...WHICH MAY STILL BE TOO HIGH. ONSHORE FLOW
WITH OVER-RUNNING SETTING UP IN THE AFTERNOON SUGGEST AT LEAST
THE CHC FOR LIGHT RAIN OR DRIZZLE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT TO OUR SOUTH TRIES TO NUDGE NORTH THURSDAY NIGHT AS THE
PARENT LOW PRESSURE SYSTEM TO THE WEST MOVES EAST. MOISTURE IS NOT
DEEP...SO EXPECTING LIGHT RAIN AND DRIZZLE TO BECOME LIKELY AS THE
NIGHT PROGRESSES.
MODELS CONTINUE TO SHOW A SECONDARY LOW FORMING...THEN PASSING OVER
OR JUST SOUTH OF THE TRI-STATE AREA LATE-DAY FRIDAY OR FRIDAY NIGHT.
STILL SOME UNCERTAINTY REGARDING THE NATURE OF THE RAINFALL BEING
MORE STRATIFORM OR CONVECTIVE...HOWEVER THERE IS GOOD CONFIDENCE IN
THE OCCURRENCE OF RAIN ON FRIDAY WITH FORCING FROM THE LOW AND THE
PRECEDING LOW LEVEL JET. KEPT ANY MENTION OF THUNDER AS
ISOLATED FOR NOW...WITH BEST CHANCES ACROSS THE SOUTHERN
SECTIONS...SINCE THIS AREA WOULD MORE LIKELY BE WARM-SECTORED.
GREATEST IMPACT POTENTIAL FROM THIS STORM WOULD BE MINOR FLOODING
DUE TO HEAVY DOWNPOURS IN ANY CONVECTION. SEE THE HYDROLOGY SECTION
BELOW FOR MORE DETAILS. OTHERWISE...THERE COULD BE A BRIEF PERIOD OF
STRONG WINDS (OUTSIDE OF ANY THUNDERSTORMS) PRIMARILY EAST OF THE
CITY FRIDAY AFTERNOON. COASTAL FLOODING DOESN`T SEEM TO BE A GREAT
CONCERN AT THIS TIME AS THE MOST SUSCEPTIBLE HIGH TIDE
CYCLE...FRIDAY MORNING`S...IS THE LOWER OF THE TWO DAILY HIGH TIDES.
RAIN CHANCES THEN TAPER OFF DURING FRIDAY EVENING WITH THE STORM
HEADING OUT TO SEA. HIGH PRESSURE THEN BUILDS IN WITH DRY WEATHER
FOR SATURDAY. THERE COULD THEN BE A SHOWER SATURDAY NIGHT WITH A
SHORTWAVE PASSING THROUGH. RIDGING AT THE SURFACE AND ALOFT THEN
KEEPS US DRY ON SUNDAY...AND LIKELY EXTENDS THROUGH MONDAY. MOISTURE
RIDING ALONG A FRONTAL BOUNDARY TO OUR WEST COULD REACH HERE AND
BRING A SHOWER IN SPOTS MONDAY NIGHT AND TUESDAY.
HIGH TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL FOR MOST SPOTS ON
FRIDAY...THEN SLIGHTLY ABOVE NORMAL ON SATURDAY...RETURNING TO NEAR
NORMAL ON SUNDAY. HIGHS THEN MODERATE ABOVE NORMAL MONDAY AND
TUESDAY.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
A FRONTAL BOUNDARY REMAINS IN THE VICINITY WITH WEAK WAVES OF LOW
PRESSURE RIDING ALONG IT THROUGH EARLY THIS MORNING AND THEN AGAIN
THIS EVENING.
VFR THROUGH AT LEAST MIDDAY TODAY. MVFR POSSIBLE THIS EVENING IN
SCT SHRA - REFLECT WITH TEMPO IN TAFS WITH MOST LIKELY TIME FRAME
AT THIS TIME. ISOLD TSRA ALSO POSSIBLE THIS EVENING - BUT
CONFIDENCE IN TIMING/EXACT LOCATIONS TOO LOW TO REFLECT IN TAFS AT
THIS TIME. GUSTY WINDS IN THE STRONGER CONVECTION IS POSSIBLE.
THE FRONTAL BOUNDARY IN THE VICINITY MAKES WIND FORECAST VERY
TRICKY AND OF VERY LOW CONFIDENCE. POSSIBLE SEABREEZE FOR
KJFK...KBDR...AND KGON. POSSIBLE SOUND BREEZE FOR KLGA ALLOWING
WINDS TO SHIFT TO THE NORTHEAST IN THE AFTERNOON.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP:/WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE IF SEA BREEZE DEVELOPS
LATER TODAY. LIGHT WINDS WITH LOW CONFIDENCE IN WIND DIRECTION.
SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KLGA FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KEWR FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KHPN FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
KISP FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...AMENDMENTS POSSIBLE DUE TO TIMING.
.OUTLOOK FOR 03Z THURSDAY THROUGH SUNDAY...
.TONIGHT...SHRA WITH ISOLD TSRA IN THE EVENING. MVFR LIKELY WITH
IFR POSSIBLE IN -RA/DZ LATE WEDNESDAY NIGHT.
.THU-THU EVENING...MVFR POSSIBLE IN LIGHT RAIN OR DRIZZLE. E
WINDS 10-15G20-25KT THU EVENING.
.LATE THU NGT AND FRI...WIDESPREAD IFR IN RAIN. E WINDS
15-25G30-40KT POSSIBLE THU NIGHT INTO FRIDAY MORNING...BECOMING NE
10-15G20-25KT IN THE AFTERNOON. LLWS AND COMPRESSION LIKELY.
.FRIDAY NIGHT...BECOMING VFR FROM W TO E.
.SATURDAY...VFR.
.SATURDAY NIGHT-SUNDAY...VFR. W-NW WIND 10-15G20-25 KT POSSIBLE.
&&
.MARINE...
QUIET WINDS/SEAS THROUGH TONIGHT AS A SERIES OF WEAK FRONTAL
WAVES MOVE ACROSS...WITH POSSIBLE TSTMS MAINLY FOR THE WATERS
SURROUNDING NYC LATE TODAY INTO THIS EVENING. LOW LEVEL MOISTURE
INCREASES BEFORE A BACK DOOR COLD FRONTAL PASSAGE LATE.
STRENGTHENING EASTERLY FLOW IN THE WAKE OF A BACK DOOR COLD FRONT. SCA
CONDITIONS LIKELY THURSDAY NIGHT AND FRIDAY WITH LOW PRESSURE
PASSING THROUGH. THERE IS A CHANCE OF DENSE FOG DEVELOPMENT
THROUGH FRIDAY MORNING AS WELL. BY FRIDAY NIGHT...WINDS
SUBSIDE...HOWEVER SEAS ON THE OCEAN WILL REMAIN AT SCA LEVELS
THROUGH AT LEAST THE DAYTIME ON SATURDAY. SUB-SCA CONDITIONS
SHOULD RETURN BY SUNDAY MORNING.&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...JC
AVIATION...JP
MARINE...JC/TONGUE
HYDROLOGY...JC/TONGUE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
518 AM EDT WED APR 10 2013
.SYNOPSIS...
WAVES OF WEAK LOW PRESSURE WILL RIDE ALONG A FRONTAL BOUNDARY
THAT REMAINS ACROSS THE REGION THROUGH TONIGHT. THE FRONT WILL
SAG SOUTH THROUGH OUR AREA AS A BACK DOOR COLD FRONT EARLY THURSDAY.
A LOW PRESSURE SYSTEM WILL MOVE THROUGH ON FRIDAY...FOLLOWED BY
BUILDING HIGH PRESSURE THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 4 AM...OUTFLOW FROM WEAKENING CONVECTION WAS ACROSS LONG
ISLAND AND HAD SHIFTED WINDS TO NORTH. WIND GUST UP TO 40 KT
OBSERVED WITH THE OUTFLOW.
EXPECT TO STAY IN A LIGHT NORTHERLY FLOW THIS MORNING...THEN TURN
AROUND TO AN INCREASING SOUTHEASTERLY FLOW. THIS WILL RESULT IN
FALLING TEMPS THIS AFTERNOON. THE SOUTHEAST FLOW IN RESPONSE TO WEAK
LOW PRESSURE OVER PA AND DIFFERENTIAL HEAT - SEA BREEZE.
TEMPS ARE BASED ON NAM AND RAP 2 METER TEMPS WHICH SUPPORT UPPER
70S FOR THE NY METRO AND AROUND 80 OVER NE NJ DESPITE CLOUD COVER
BEFORE THE SE FLOW WORKS IN.
HEATING AND SE WIND SHIFT SHOULD ALLOW FOR SCT LATE DAY CONVECTION
TO DEVELOP OVER N JERSEY. 0-6 KM BULK SHEAR SUGGESTS MARGINAL
SEVERE POTENTIAL...BUT INSTABILITY IS IN QUESTION. SPC HAS DROPPED
THE SLIGHT RISK FIR N JERSEY...WHICH I AGREE WITH...BUT WE`LL NEED TO
MONITOR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
ANOTHER WEAK LOW PASSES THROUGH THE REGION TONIGHT WITH A HIGH
DEGREE OF UNCERTAINTY ON THE SENSIBLE WX. HAVE SUGGESTED THE MAIN
PCPN CHANCE IS NORTH...BASED ON ECMWF AND GFS...BUT HAVE VERY LOW
CONFIDENCE IN THIS.
TEMPS OVERNIGHT ARE BLENDED MOS IN THE 45 TO 50 RANGE.
THE COOL MARITIME AIR REALLY COMES IN ON THURSDAY IN THE WAKE OF
THE BACKDOOR COLD FRONT WITH NEARLY STEADY TEMPS. HAVE HIGHS IN
THE LOWER TO MID 50S...WHICH MAY STILL BE TOO HIGH. ONSHORE FLOW
WITH OVER-RUNNING SETTING UP IN THE AFTERNOON SUGGEST AT LEAST
THE CHC FOR LIGHT RAIN OR DRIZZLE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT TO OUR SOUTH TRIES TO NUDGE NORTH THURSDAY NIGHT AS THE
PARENT LOW PRESSURE SYSTEM TO THE WEST MOVES EAST. MOISTURE IS NOT
DEEP...SO EXPECTING LIGHT RAIN AND DRIZZLE TO BECOME LIKELY AS THE
NIGHT PROGRESSES.
MODELS CONTINUE TO SHOW A SECONDARY LOW FORMING...THEN PASSING OVER
OR JUST SOUTH OF THE TRI-STATE AREA LATE-DAY FRIDAY OR FRIDAY NIGHT.
STILL SOME UNCERTAINTY REGARDING THE NATURE OF THE RAINFALL BEING
MORE STRATIFORM OR CONVECTIVE...HOWEVER THERE IS GOOD CONFIDENCE IN
THE OCCURRENCE OF RAIN ON FRIDAY WITH FORCING FROM THE LOW AND THE
PRECEDING LOW LEVEL JET. KEPT ANY MENTION OF THUNDER AS
ISOLATED FOR NOW...WITH BEST CHANCES ACROSS THE SOUTHERN
SECTIONS...SINCE THIS AREA WOULD MORE LIKELY BE WARM-SECTORED.
GREATEST IMPACT POTENTIAL FROM THIS STORM WOULD BE MINOR FLOODING
DUR TO HEAVY DOWNPOURS IN ANY CONVECTION. SEE THE HYDROLOGY SECTION
BELOW FOR MORE DETAILS. OTHERWISE...THERE COULD BE A BRIEF PERIOD OF
STRONG WINDS (OUTSIDE OF ANY THUNDERSTORMS) PRIMARILY EAST OF THE
CITY FRIDAY AFTERNOON. COASTAL FLOODING DOESN`T SEEM TO BE A GREAT
CONCERN AT THIS TIME AS THE MOST SUSCEPTIBLE HIGH TIDE
CYCLE...FRIDAY MORNING`S...IS THE LOWER OF THE TWO DAILY HIGH TIDES.
RAIN CHANCES THEN TAPER OFF DURING FRIDAY EVENING WITH THE STORM
HEADING OUT TO SEA. HIGH PRESSURE THEN BUILDS IN WITH DRY WEATHER
FOR SATURDAY. THERE COULD THEN BE A SHOWER SATURDAY NIGHT WITH A
SHORTWAVE PASSING THROUGH. RIDGING AT THE SURFACE AND ALOFT THEN
KEEPS US DRY ON SUNDAY...AND LIKELY EXTENDS THROUGH MONDAY. MOISTURE
RIDING ALONG A FRONTAL BOUNDARY TO OUR WEST COULD REACH HERE AND
BRING A SHOWER IN SPOTS MONDAY NIGHT AND TUESDAY.
HIGH TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL FOR MOST SPOTS ON
FRIDAY...THEN SLIGHTLY ABOVE NORMAL ON SATURDAY...RETURNING TO NEAR
NORMAL ON SUNDAY. HIGHS THEN MODERATE ABOVE NORMAL MONDAY AND
TUESDAY.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
A FRONTAL BOUNDARY REMAINS IN THE VICINITY WITH WEAK WAVES OF LOW
PRESSURE RIDING ALONG IT THROUGH EARLY THIS MORNING AND THEN AGAIN
THIS EVENING.
VFR THROUGH AT LEAST MIDDAY TODAY. MVFR POSSIBLE THIS EVENING IN
SCT SHRA - REFLECT WITH TEMPO IN TAFS WITH MOST LIKELY TIME FRAME
AT THIS TIME. ISOLD TSRA ALSO POSSIBLE THIS EVENING - BUT
CONFIDENCE IN TIMING/EXACT LOCATIONS TOO LOW TO REFLECT IN TAFS AT
THIS TIME. GUSTY WINDS IN THE STRONGER CONVECTION IS POSSIBLE.
THE FRONTAL BOUNDARY IN THE VICINITY MAKES WIND FORECAST VERY
TRICKY AND OF VERY LOW CONFIDENCE. POSSIBLE SEABREEZE FOR KJFK AND
SOUND BREEZE FOR KLGA ALLOWING WINDS TO SHIFT TO THE NORTHEAST
IN THE AFTERNOON. WHILE WINDS WILL BE LIGHT AT THE SURFACE
WINDS...AT 2000FT INCREASE TO 35 TO JUST UNDER 50KT FROM AROUND
9-12Z. CONFIDENCE IS NOT HIGH ENOUGH TO KEEP LLWS OF 50 KT IN
TAFS...BUT LLWS BETWEEN 35 TO JUST UNDER 50 KT IS MORE LIKELY
EVERYWHERE EXCEPT KSWF AND KGON.
...NY METRO ENHANCED AVIATION WEATHER SUPPORT...
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS
CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)
KJFK FCSTER COMMENTS: AMENDMENTS POSSIBLE IF SEA BREEZE DEVELOPS
LATER TODAY. LIGHT WINDS WITH LOW CONFIDENCE IN WIND DIRECTION.
SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS EVENING...COULD
OCCUR A FEW HOURS EARLIER THAN FORECAST.
KLGA FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...COULD OCCUR A FEW HOURS EARLIER THAN FORECAST.
KEWR FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...COULD OCCUR A FEW HOURS EARLIER THAN FORECAST.
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH
IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.
KTEB FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...COULD OCCUR A FEW HOURS EARLIER THAN FORECAST.
KHPN FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...COULD OCCUR A FEW HOURS EARLIER THAN FORECAST.
KISP FCSTER COMMENTS: LIGHT WINDS WITH LOW CONFIDENCE IN WIND
DIRECTION. SHOWERS AND AN ISOLATED THUNDERSTORM POSSIBLE THIS
EVENING...COULD OCCUR A FEW HOURS EARLIER THAN FORECAST.
.OUTLOOK FOR 03Z THURSDAY THROUGH SUNDAY...
.TONIGHT...SHRA WITH ISOLD TSRA IN THE EVENING. MVFR LIKELY WITH
IFR POSSIBLE IN -RA/DZ LATE WEDNESDAY NIGHT.
.THU-THU EVENING...MVFR POSSIBLE IN LIGHT RAIN OR DRIZZLE. E
WINDS 10-15G20-25KT THU EVENING.
.LATE THU NGT AND FRI...WIDESPREAD IFR IN RAIN. E WINDS
15-25G30-40KT POSSIBLE THU NIGHT INTO FRIDAY MORNING...BECOMING NE
10-15G20-25KT IN THE AFTERNOON. LLWS AND COMPRESSION LIKELY.
.FRIDAY NIGHT...BECOMING VFR FROM W TO E.
.SATURDAY...VFR.
.SATURDAY NIGHT-SUNDAY...VFR. W-NW WIND 10-15G20-25 KT POSSIBLE.
&&
.MARINE...
QUIET WINDS/SEAS THROUGH TONIGHT AS A SERIES OF WEAK FRONTAL
WAVES MOVE ACROSS...WITH POSSIBLE TSTMS MAINLY FOR THE WATERS
SURROUNDING NYC LATE TODAY INTO THIS EVENING. LOW LEVEL MOISTURE
INCREASES BEFORE A BACK DOOR COLD FRONTAL PASSAGE LATE.
STRENGTHENING EASTERLY FLOW IN THE WAKE OF A BACK DOOR COLD FRONT. SCA
CONDITIONS LIKELY THURSDAY NIGHT AND FRIDAY WITH LOW PRESSURE
PASSING THROUGH. THERE IS A CHANCE OF DENSE FOG DEVELOPMENT
THROUGH FRIDAY MORNING AS WELL. BY FRIDAY NIGHT...WINDS
SUBSIDE...HOWEVER SEAS ON THE OCEAN WILL REMAIN AT SCA LEVELS
THROUGH AT LEAST THE DAYTIME ON SATURDAY. SUB-SCA CONDITIONS
SHOULD RETURN BY SUNDAY MORNING.&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...JC
AVIATION...JP
MARINE...JC/TONGUE
HYDROLOGY...JC/TONGUE
AREA FORECAST DISCUSSION
NWS NEW YORK NY
427 AM EDT WED APR 10 2013
.SYNOPSIS...
WAVES OF WEAK LOW PRESSURE WILL RIDE ALONG A FRONTAL BOUNDARY
THAT REMAINS ACROSS THE REGION THROUGH TONIGHT. THE FRONT WILL
SAG SOUTH THROUGH OUR AREA AS A BACK DOOR COLD FRONT EARLY THURSDAY.
A LOW PRESSURE SYSTEM WILL MOVE THROUGH ON FRIDAY...FOLLOWED BY
BUILDING HIGH PRESSURE THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 4 AM...OUTFLOW FROM WEAKENING CONVECTION WAS ACROSS LONG
ISLAND AND HAD SHIFTED WINDS TO NORTH. WIND GUST UP TO 40 KT
OBSERVED WITH THE OUTFLOW.
EXPECT TO STAY IN A LIGHT NORTHERLY FLOW THIS MORNING...THEN TURN
AROUND TO AN INCREASING SOUTHEASTERLY FLOW. THIS WILL RESULT IN
FALLING TEMPS THIS AFTERNOON. THE SOUTHEAST FLOW IN RESPONSE TO WEAK
LOW PRESSURE OVER PA AND DIFFERENTIAL HEAT - SEA BREEZE.
TEMPS ARE BASED ON NAM AND RAP 2 METER TEMPS WHICH SUPPORT UPPER
70S FOR THE NY METRO AND AROUND 80 OVER NE NJ DESPITE CLOUD COVER
BEFORE THE SE FLOW WORKS IN.
HEATING AND SE WIND SHIFT SHOULD ALLOW FOR SCT LATE DAY CONVECTION
TO DEVELOP OVER N JERSEY. 0-6 KM BULK SHEAR SUGGESTS MARGINAL
SEVERE POTENTIAL...BUT INSTABILITY IS IN QUESTION. SPC HAS DROPPED
THE SLIGHT RISK FIR N JERSEY...WHICH I AGREE WITH...BUT WE`LL NEED TO
MONITOR.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
ANOTHER WEAK LOW PASSES THROUGH THE REGION TONIGHT WITH A HIGH
DEGREE OF UNCERTAINTY ON THE SENSIBLE WX. HAVE SUGGESTED THE MAIN
PCPN CHANCE IS NORTH...BASED ON ECMWF AND GFS...BUT HAVE VERY LOW
CONFIDENCE IN THIS.
TEMPS OVERNIGHT ARE BLENDED MOS IN THE 45 TO 50 RANGE.
THE COOL MARITIME AIR REALLY COMES IN ON THURSDAY IN THE WAKE OF
THE BACKDOOR COLD FRONT WITH NEARLY STEADY TEMPS. HAVE HIGHS IN
THE LOWER TO MID 50S...WHICH MAY STILL BE TOO HIGH. ONSHORE FLOW
WITH OVER-RUNNING SETTING UP IN THE AFTERNOON SUGGEST AT LEAST
THE CHC FOR LIGHT RAIN OR DRIZZLE.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT TO OUR SOUTH TRIES TO NUDGE NORTH THURSDAY NIGHT AS THE
PARENT LOW PRESSURE SYSTEM TO THE WEST MOVES EAST. MOISTURE IS NOT
DEEP...SO EXPECTING LIGHT RAIN AND DRIZZLE TO BECOME LIKELY AS THE
NIGHT PROGRESSES.
MODELS CONTINUE TO SHOW A SECONDARY LOW FORMING...THEN PASSING OVER
OR JUST SOUTH OF THE TRI-STATE AREA LATE-DAY FRIDAY OR FRIDAY NIGHT.
STILL SOME UNCERTAINTY REGARDING THE NATURE OF THE RAINFALL BEING
MORE STRATIFORM OR CONVECTIVE...HOWEVER THERE IS GOOD CONFIDENCE IN
THE OCCURRENCE OF RAIN ON FRIDAY WITH FORCING FROM THE LOW AND THE
PRECEDING LOW LEVEL JET. KEPT ANY MENTION OF THUNDER AS
ISOLATED FOR NOW...WITH BEST CHANCES ACROSS THE SOUTHERN
SECTIONS...SINCE THIS AREA WOULD MORE LIKELY BE WARM-SECTORED.
GREATEST IMPACT POTENTIAL FROM THIS STORM WOULD BE MINOR FLOODING
DUR TO HEAVY DOWNPOURS IN ANY CONVECTION. SEE THE HYDROLOGY SECTION
BELOW FOR MORE DETAILS. OTHERWISE...THERE COULD BE A BRIEF PERIOD OF
STRONG WINDS (OUTSIDE OF ANY THUNDERSTORMS) PRIMARILY EAST OF THE
CITY FRIDAY AFTERNOON. COASTAL FLOODING DOESN`T SEEM TO BE A GREAT
CONCERN AT THIS TIME AS THE MOST SUSCEPTIBLE HIGH TIDE
CYCLE...FRIDAY MORNING`S...IS THE LOWER OF THE TWO DAILY HIGH TIDES.
RAIN CHANCES THEN TAPER OFF DURING FRIDAY EVENING WITH THE STORM
HEADING OUT TO SEA. HIGH PRESSURE THEN BUILDS IN WITH DRY WEATHER
FOR SATURDAY. THERE COULD THEN BE A SHOWER SATURDAY NIGHT WITH A
SHORTWAVE PASSING THROUGH. RIDGING AT THE SURFACE AND ALOFT THEN
KEEPS US DRY ON SUNDAY...AND LIKELY EXTENDS THROUGH MONDAY. MOISTURE
RIDING ALONG A FRONTAL BOUNDARY TO OUR WEST COULD REACH HERE AND
BRING A SHOWER IN SPOTS MONDAY NIGHT AND TUESDAY.
HIGH TEMPERATURES ARE EXPECTED TO BE BELOW NORMAL FOR MOST SPOTS ON
FRIDAY...THEN SLIGHTLY ABOVE NORMAL ON SATURDAY...RETURNING TO NEAR
NORMAL ON SUNDAY. HIGHS THEN MODERATE ABOVE NORMAL MONDAY AND
TUESDAY.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
LINE OF SHOWERS AND THUNDERSTORMS CURRENTLY MOVING THROUGH LOWER
HUDSON VALLEY WILL PRIMARILY AFFECT KSWF THROUGH 08Z. WIND GUSTS
UP TO 40 KT WITH MVFR VSBY ARE POSSIBLE AS THE LINE MOVES THROUGH.
A FRONTAL BOUNDARY REMAINS IN THE VICINITY WITH WEAK WAVES OF LOW
PRESSURE RIDING ALONG IT THROUGH EARLY THIS MORNING AND THEN AGAIN
THIS EVENING.
VFR THROUGH AT LEAST MIDDAY TODAY. MVFR POSSIBLE LATE WEDNESDAY
AFTERNOON IN SCT SHRA - REFLECT WITH TEMPO IN TAFS WITH MOST
LIKELY TIME FRAME AT THIS TIME. ISOLD TSRA ALSO POSSIBLE LATE
AFTERNOON - BUT CONFIDENCE IN TIMING/EXACT LOCATIONS TOO LOW TO
REFLECT IN TAFS AT THIS TIME. GUSTY WINDS IN THE STRONGER
CONVECTION IS POSSIBLE.
WAVY FRONTAL BOUNDARY IN THE VICINITY MAKES WIND FORECAST VERY
TRICKY AND OF VERY LOW CONFIDENCE. IN GENERAL LIGHT AND VARIABLE
WINDS. WINDS BRIEFLY GO NW-N THIS MORNING - THEN BECOME LIGHT AND
VARIABLE AGAIN THIS AFTERNOON. EXCEPTION IS LGA SHOULD SEE
AFTERNOON NE SOUND BREEZE AND KJFK/KGON AFTERNOON S-SE SEA BREEZE.
WHILE WINDS WILL BE LIGHT AT THE SURFACE WINDS...AT 2000FT
INCREASE TO 35 TO JUST UNDER 50KT FROM AROUND 9-12Z. CONFIDENCE IS
NOT HIGH ENOUGH TO KEEP LLWS OF 50 KT IN TAFS...BUT LLWS BETWEEN
35 TO JUST UNDER 50 KT IS MORE LIKELY EVERYWHERE EXCEPT KSWF AND KGON.
.OUTLOOK FOR 03Z THURSDAY THROUGH SUNDAY...
.TONIGHT...SHRA WITH ISOLD TSRA IN THE EVENING. MVFR LIKELY WITH
IFR POSSIBLE IN -RA/DZ LATE WEDNESDAY NIGHT.
.THU-THU EVENING...MVFR POSSIBLE IN LIGHT RAIN OR DRIZZLE. E
WINDS 10-15G20-25KT THU EVENING.
.LATE THU NGT AND FRI...WIDESPREAD IFR IN RAIN. E WINDS
15-25G30-40KT POSSIBLE THU NIGHT INTO FRIDAY MORNING...BECOMING NE
10-15G20-25KT IN THE AFTERNOON. LLWS AND COMPRESSION LIKELY.
.FRIDAY NIGHT...BECOMING VFR FROM W TO E.
.SATURDAY...VFR.
.SATURDAY NIGHT-SUNDAY...VFR. W-NW WIND 10-15G20-25 KT POSSIBLE.
&&
.MARINE...
QUIET WINDS/SEAS THROUGH TONIGHT AS A SERIES OF WEAK FRONTAL
WAVES MOVE ACROSS...WITH POSSIBLE TSTMS MAINLY FOR THE WATERS
SURROUNDING NYC LATE TODAY INTO THIS EVENING. LOW LEVEL MOISTURE
INCREASES BEFORE A BACK DOOR COLD FRONTAL PASSAGE LATE.
STRENGTHENING EASTERLY FLOW IN THE WAKE OF A BACK DOOR COLD FRONT. SCA
CONDITIONS LIKELY THURSDAY NIGHT AND FRIDAY WITH LOW PRESSURE
PASSING THROUGH. THERE IS A CHANCE OF DENSE FOG DEVELOPMENT
THROUGH FRIDAY MORNING AS WELL. BY FRIDAY NIGHT...WINDS
SUBSIDE...HOWEVER SEAS ON THE OCEAN WILL REMAIN AT SCA LEVELS
THROUGH AT LEAST THE DAYTIME ON SATURDAY. SUB-SCA CONDITIONS
SHOULD RETURN BY SUNDAY MORNING.&&
.HYDROLOGY...
SCATTERED LIGHT RAINFALL THROUGH THURSDAY...THEN A MORE SIGNIFICANT
RAINFALL EVENT FOR FRIDAY WITH 1 TO 1 1/2 INCHES IS EXPECTED. MINOR
URBAN AND POOR DRAINAGE PONDING IS LIKELY. RIVER FLOODING IS NOT
EXPECTED.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...JC/TONGUE
NEAR TERM...TONGUE
SHORT TERM...TONGUE
LONG TERM...JC
AVIATION...JP
MARINE...JC/TONGUE
HYDROLOGY...JC/TONGUE
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1032 AM EDT WED APR 10 2013
.SYNOPSIS...
A FRONTAL BOUNDARY DRAPED FROM OHIO THEN ACROSS NORTHERN
PENNSYLVANIA TO THE WATERS OFF NEW JERSEY WILL REMAIN NEARLY
STATIONARY INTO TONIGHT. THIS FRONT THEN SETTLES SOUTHWARD ACROSS
THE REGION LATE TONIGHT AND THURSDAY. A LOW PRESSURE SYSTEM IS
FORECAST TO TRACK ACROSS THE EASTERN GREAT LAKES REGION THURSDAY
NIGHT AND FRIDAY, WITH A WEAK LOW POSSIBLY DEVELOPING ALONG THE
COLD FRONT. THE ACTUAL COLD FRONT THEN SWEEPS ACROSS OUR AREA
LATER FRIDAY. HIGH PRESSURE GRADUALLY BUILDS IN OVER THE WEEKEND
BEFORE SHIFTING OFFSHORE INTO MONDAY. THE NEXT COLD FRONT SHOULD
APPROACH FROM THE WEST DURING TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FRONTAL BOUNDARY EXTENDED ACROSS NORTHEASTERN BERKS COUNTY TO
AROUND NORTHEAST PHILADELPHIA THEN OFF THE NEW JERSEY COAST AROUND
POINT PLEASANT AND SEASIDE HEIGHTS AT 900 AM. THE BOUNDARY MAY
LIFT NORTHWARD A BIT DURING THE DAYLIGHT HOURS. THE SKY WAS MAINLY
CLEAR OVER OUR REGION TO THE SOUTH OF THE BOUNDARY WITH A PARTLY
CLOUDY SKY TO THE NORTH.
IT APPEARS AS THOUGH TEMPERATURES WILL SOAR INTO THE MIDDLE AND
UPPER 80S TO THE SOUTH OF THE PENNSYLVANIA TURNPIKE AND INTERSTATE
195 TODAY WITH A GOOD AMOUNT OF SUNSHINE. READINGS MAY BE A BIT
LOWER RIGHT ALONG THE COAST. THE FRONTAL BOUNDARY SHOULD KEEP
TEMPERATURES A BIT COOLER ACROSS THE NORTHERN HALF OF OUR FORECAST
AREA. MAXIMUM READINGS ARE ANTICIPATED TO BE AROUND 80 THERE WITH
TEMPERATURES REACHING ONLY THE MIDDLE 70S IN THE ELEVATED TERRAIN.
THE LATEST HRRR KEEPS OUR FORECAST AREA PRECIPITATION FREE UNTIL
600 PM. THE 0600 UTC NAM AND THE 0600 UTC GFS ARE ABOUT AN HOUR OR
TWO FASTER THAN THE HRRR. THE SREF ALSO LEANS TOWARD AN EARLIER
SOLUTION. THERE REMAINS SOME CONCERN THAT THE MODELS ARE
OVERPLAYING THE LOW LEVEL MOISTURE FOR THIS AFTERNOON. REGARDLESS,
WE CONTINUE TO EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO
BUILD ACROSS THE NORTHERN HALF OF OUR FORECAST AREA DURING THE
LATE AFTERNOON.
THE STORM PREDICTION CENTER HAS MUCH OF OUR FORECAST AREA UNDER
THEIR SLIGHT RISK FOR SEVERE WEATHER DESIGNATION FOR TODAY. WE
WILL CONTINUE TO MONITOR THE STABILITY PARAMETERS AS THE LATE
MORNING AND EARLY AFTERNOON PROGRESS, AS WELL AS THE TRENDS IN
CONVECTIVE DEVELOPMENT UPSTREAM.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
FCST PROBLEMS ARE THE SWD PROGRESSION OF THE BACKDOOR...THE UKMET
BEING MUCH FURTHER N THAN THE RGEM/NAM AND NOW THE MUCH FURTHER
SOUTH 00Z/10 GFS.
AND THE OTHER FCST PROBLEM...ANY SVR CONVECTION THIS EVENING.
AT THE LAST MINUTE JUST BEFORE THE 330AM FCST RELEASE I BOOSTED
POPS IN E PA AND NJ TONIGHT FOR AN OPPORTUNITY OF ESEWD MOVING BOW
ECHO OUT OF NRN PA FOR THE LEHIGH VALLEY AND CENTRAL NJ.
THE RECEIPT OF THE 06Z/10 HPC QPF FCST AND THE 00Z/10 ECMWF MASS
FIELDS AND QPF LOCKED ME INTO A 4-6 HOUR WINDOW OF OPPORTUNITY FOR
HEAVY CONVECTION. LOOK WHAT HAPPENED EARLY THIS MORNING...KISP 31
KTS AT 0747Z WITH 45 KT 0-6KM MODELED BULK SHEAR AND NO ML CAPE
NEARBY.
I THINK THIS COULD BE BUSY EVENING WITH POTENTIAL FOR SCT
DAMAGING WIND GUSTS BETWEEN I-80 AND I76-I195.
TEMPS: 50 50 BLEND OF THE 00Z/10 GFS/NAM MOS 3HRLY TEMPS FOR THE
LOW.
DEWPOINTS: 50 50 BLENDED 00Z/10 GFS/NAM MOS GUIDANCE.
WINDS: AN EQUAL BLEND OF THE 00Z/10 GFS/NAM MOS WITH THE 2M WINDS
OF THE RGEM/NAM. THAT MEANS CHILLING OCEAN BREEZES DEVELOP THE NNJ
COASTAL WATERS SOMETIME LATE THIS MORNING.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE OVERALL SYNOPTIC SETUP IS COMPRISED OF RIDGING ALONG THE MID
ATLANTIC COAST THURSDAY WITH A STRONG TROUGH FROM THE MIDWEST TO
THE LOWER MISSISSIPPI VALLEY. THIS FEATURE WILL BE THE MAIN ONE AS
WE GO THROUGH LATE THURSDAY AND FRIDAY, THEN WE TRANSITION BACK
INTO A TROUGH ACROSS THE NORTHEAST OVER THE WEEKEND, HOWEVER SOME
RIDGING LOOKS TO ARRIVE EARLY NEXT WEEK. THE MAIN FORECAST
CHALLENGES ARE CENTERED ON A BACKDOOR FRONT SETTLING SOUTH ACROSS
THE AREA THURSDAY, WHICH COULD RESULT IN A SIGNIFICANT TEMPERATURE
GRADIENT FROM SOUTH TO NORTH, THEN A STRONG COLD FRONT LATER
FRIDAY. THERE IS LOWER CONFIDENCE WITH TEMPERATURES THURSDAY AS
THE PLACEMENT OF THE BOUNDARY WILL BE CRUCIAL AS AN ONSHORE FLOW
IS NORTH OF IT. WE GENERALLY USED A BLEND OF MODEL GUIDANCE AND
CONTINUITY THURSDAY THROUGH SATURDAY, THEN BLENDED IN SOME OF THE
NEW WPC GUIDANCE WITH CONTINUITY THEREAFTER.
FOR THURSDAY...A TRICKY FORECAST REGARDING THE DETAILS AS A
FRONTAL BOUNDARY DRAPED EAST TO WEST IS FORECAST TO SETTLE
SOUTHWARD AS A BACKDOOR COLD FRONT. THE SOUTHWARD PROGRESSION OF
THIS FRONT MAY BE ENHANCED SOME BY SHOWERS AND/OR ELEVATED
CONVECTION TO ITS NORTH. THIS WILL ALSO HELP TO STRENGTHEN THE
THERMAL GRADIENT ALONG IT. THE MODEL GUIDANCE IN GENERAL SEEMS TO
BE SENDING THIS LOW-LEVEL FRONT A BIT FARTHER SOUTH, WHICH TURNS
THE SURFACE WINDS OUT OF THE EAST AND NORTHEAST. THIS WOULD RESULT
IN LOW CLOUDS AND PERHAPS SOME LIGHT RAIN OR DRIZZLE. THERE WILL
LIKELY BE A SIGNIFICANT TEMPERATURE GRADIENT WITH THIS BOUNDARY,
WHICH CAN LEAD TO A HIGH BUST POTENTIAL IN THE TEMPERATURE
DEPARTMENT. HOWEVER, THE STRONGEST LIFT LOOKS TO BE MOSTLY NORTH
OF OUR AREA. THIS WOULD POINT TO A MORE LIGHT RAIN OR DRIZZLE TYPE
SCENARIO AS THE EASTERLY FLOW SETS UP AND THE LOW-LEVEL MOISTURE
DEEPENS BENEATH AN INVERSION.
WE THEREFORE USED A BLEND OF THE NAM/GFS MOS WITH SOME
INCORPORATION OF THE ECMWF. THIS SEEMS TO DEPICT A DECENT DOWNWARD
TREND THAT WE ARE SEEING REGARDING HIGH TEMPERATURES. AS MENTIONED
THERE IS A BUST POTENTIAL WITH THIS AS SOUTH OF THE FRONT IT WILL
BE RATHER WARM. TEMPERATURES MAY ACTUALLY FALL SOME DURING THE DAY
NORTH OF THE FRONT AS THE LOW-LEVEL CAA OCCURS WITHIN AN EASTERLY
FLOW. WE MAINTAINED SLIGHT CHC TO CHC POPS GRADUALLY FROM NORTH TO
SOUTH DURING THE DAY WITH SHOWER WORDING TRANSITIONING OVER TO
RAIN/DRIZZLE TOWARD EVENING ACROSS THE NORTHEASTERN PART OF THE
CWA. THIS IS DUE TO THE ONSHORE FLOW AND COOLING FORECAST TO TAKE
PLACE. THERE COULD BE SOME FOG DEVELOPING AS WELL, DUE TO THE LOW-
LEVEL MOISTURE AND ONSHORE FLOW COMBINED WITH THE COOLER AIR
UNDERCUTTING THE WARMER AIR. HOWEVER, NOT CONFIDENT ON THE EXTENT
OF THIS, THEREFORE DID NOT INCLUDE ATTM.
AS WE GO THROUGH THURSDAY NIGHT, THE AFOREMENTIONED BACKDOOR
FRONT WILL PROBABLY TRY AND LIFT NORTHWARD AT LEAST SOME LATE AS
INCREASING WAA AND FLOW ARRIVES AHEAD OF THE NEXT SYSTEM. THIS
WILL BE LOW PRESSURE TRACKING TOWARD THE EASTERN GREAT LAKES
REGION. THERE IS PLENTY OF MOISTURE FORECAST TO SURGE AHEAD OF
THIS FEATURE ALONG WITH DECENT LARGE SCALE LIFT AND EVEN FRONTAL
FORCING. AS THE WARMER AND MORE MOIST AIR IS LIFTED OVER THE
EXISTING COOLER LOW-LEVEL AIR MASS OVER MUCH OF OUR AREA, AT LEAST
SOME ELEVATED INSTABILITY IS FORECAST. THIS COULD BE ENOUGH TO
GENERATE SOME THUNDERSTORMS FROM WEST TO EAST. THERE MAY BE STRONG
LINEAR FORCING AHEAD OF THE COLD/OCCLUDING FRONT TO RESULT IN A
NARROW CONVECTIVE LINE. WE GENERALLY MAINTAINED CONTINUITY WHICH
SHOWS POPS INCREASING TO LIKELY AND CATEGORICAL THROUGH THE NIGHT.
WE DID HOWEVER START WITH LIGHT RAIN/DRIZZLE WORDING THEN
TRANSITIONED OVER TO SHOWERS AS INCREASING ASCENT ARRIVES. IT IS
POSSIBLE THAT TEMPERATURES RISE SOME ACROSS THE FAR SOUTHERN ZONES
LATE AS THE BOUNDARY STARTS TO SHIFT NORTHWARD AS A WARM FRONT.
FOR FRIDAY...A SURFACE LOW GENERALLY TRACKS UP ACROSS THE GREAT
LAKES REGION, THEN AN OCCLUDED FRONT ARRIVES INTO OUR AREA. THERE
COULD BE A WEAK LOW DEVELOPING AT THE TRIPLE POINT, AND THIS WILL
DETERMINE WHERE THE FRONT IS DRAPED THAT EVENTUALLY SHIFTS
NORTHWARD SOME AS A WARM FRONT. OUR ENTIRE AREA MAY GET INTO THE
SOUTHERLY FLOW AHEAD OF THE MAIN FRONT FOR A TIME DURING THE
AFTERNOON, HOWEVER THIS IS TRICKY WITH THE TIMING AND WILL LIKELY
HAVE AN IMPACT ON OUR TEMPERATURES. NORTH OF THE FRONT THERE WILL
BE LINGERING LOW-LEVEL EASTERLY WINDS KEEPING MOISTURE LOCKED IN,
THEREFORE IF WE CAN VEER THE WINDS TO MORE SOUTHERLY FAST ENOUGH
SOME ADDITIONAL WARMING PERHAPS OCCURS.
THE FORECAST SOUNDINGS SHOW A STRENGTHENING AND VEERING FLOW
BELOW 10,000 FEET FOR A TIME FRIDAY PRIOR TO THE COLD FRONTAL
PASSAGE. ASSUMING MUCH OF THE AREA IS UNDER AN EASTERLY FLOW FOR A
TIME, THE LOWER LEVELS WILL BE STABLE BUT SOME ELEVATED
INSTABILITY IS HINTED AT TO START THE DAY, BUT THEN INCREASING AT
LEAST SOME. THE DELMARVA MAY HAVE A BETTER CHC OF SEEING SURFACE
BASED INSTABILITY. THIS IN COMBINATION WITH THE LINEAR FORCING
WITH THE FRONT COULD RESULT IN SOME THUNDERSTORMS, WHICH COULD BE
IN THE FORM OF NARROW LINE SEGMENTS. SOME GUIDANCE SHOWING A
DECENT AMOUNT OF INSTABILITY WORKING IN ALONG WITH HIGHER SHEAR,
THEREFORE SOME STRONG/SEVERE CONVECTION CANNOT BE RULED OUT
ESPECIALLY IF WE CAN ERODE ANY STABLE LOW-LEVEL ENVIRONMENT. AS OF
NOW, WE HELD OFF ON ANY ENHANCED WORDING IN THE FORECAST WITH THIS
SYSTEM DUE TO DETAIL UNCERTAINTIES. THE PW VALUES HOWEVER ARE
FORECAST TO BE AROUND 1.5 INCHES AHEAD OF THE FRONT, THEREFORE
LOCALLY HEAVY RAINFALL WILL CERTAINLY BE POSSIBLE ESPECIALLY
FRIDAY MORNING. WE DID NOTE THE 00Z ECMWF IS A LITTLE SLOWER WITH
THE MAIN PRECIPITATION.
FOR SATURDAY AND SUNDAY...AN UPPER-LEVEL TROUGH WILL BE SETTLING
INTO THE NORTHEAST, AS A COLD FRONT IS EAST OF OUR AREA TO START
SATURDAY. THERE MAY BE A SECONDARY COOL FRONT OR SURFACE TROUGH
THAT SWINGS THROUGH LATE IN THE DAY SATURDAY, HOWEVER MOISTURE AND
FORCING LOOKS WEAK. OTHERWISE, A COOLER AIR MASS WILL BE IN PLACE
AS CAA OCCURS. HIGH PRESSURE SLIDING INTO THE UPPER OHIO VALLEY
SATURDAY WILL MAINTAIN A TIGHTER PRESSURE GRADIENT ACROSS OUR
AREA, THEREFORE A WESTERLY BREEZE IS ANTICIPATED. A STRONG SHORT
WAVE SLIDES ACROSS THE AREA SATURDAY NIGHT WITH PERHAPS A SHOWER
AROUND, ALTHOUGH THE AIR MASS MAY BE A LITTLE TO DRY. WE WILL KEEP
A DRY FORECAST ATTM.
HIGH PRESSURE SHOULD THEN BE TRANSITIONING TO OUR EAST DURING
SUNDAY. THIS WILL RESULT IN LESS WIND WITH TIME AND ALSO HELP WITH
THE WAA DEVELOPING UP THE OHIO VALLEY. THIS SHOULD HELP ORGANIZE A
WARM FRONT THAT LIFTS BY MOSTLY TO OUR NORTHWEST SUNDAY NIGHT.
SOME GUIDANCE SHOWS STRONG WAA AND ISENTROPIC UPGLIDE FARTHER
EAST, WHICH WOULD BRING SOME SHOWERS INTO PORTIONS OF OUR AREA.
THIS MAY BE OVERDONE, THEREFORE WE OPTED TO KEEP A DRY FORECAST
GOING ATTM.
FOR MONDAY AND TUESDAY...THE NEXT SYSTEM IS FORECAST TO TRACK
GENERALLY UP ACROSS THE GREAT LAKES LATE MONDAY AND TUESDAY. THIS
PLACES A WARM FRONT TO OUR NORTH, THEN THE ASSOCIATED COLD FRONT
ARRIVES AS WE GO THROUGH TUESDAY. THERE IS UNCERTAINTY WITH THE
TIMING AS SOME GUIDANCE IS MUCH FASTER WITH THE ARRIVAL OF THE
COLD FRONT. WE THEREFORE STAYED CLOSE TO CONTINUITY/WPC GUIDANCE
WHICH SHOWS A SLOWER ARRIVAL OF THE COLD FRONT. SLIGHT CHC OR LOW
CHC POPS REMAIN IN THE DATABASE MAINLY ALONG AND NORTH/WEST OF
INTERSTATE 95 MONDAY NIGHT AND TUESDAY. A WARMER AIR MASS WILL
ARRIVE AHEAD OF THE COLD FRONT, THEREFORE THIS IS REFLECTED IN THE
TEMPERATURES.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR WITH WESTERLY WIND GUSTS TO AROUND 20 KTS MIDDAY AND
THIS AFTN...POSSIBLY 25 KT IN DE. SCT TO BKN CLOUDS AOA 6000 FT. A
CHANCE OF A TSTM AFTER 20Z OVER E PA. CONFIDENCE ON CONVECTION IS
MUCH BELOW AVG DUE TO MOISTURE AVAILABILITY. IF CONVECTION
DEVELOPS IN W PA AND MOVES EAST...IT COULD BE ACCOMPANIED BY A NW
WIND GUST TO 45 KT BUT JUST DONT KNOW IF TSTMS CAN DEVELOP THIS
AFTN. THE POSSIBILITY OF STRONG TSTMS LATE TODAY NEEDS TO BE
MAINTAINED AS AN OPTION IN FLIGHT PREPARATIONS....PARTICULARLY IN
PA AND THE N/2RDS NJ. WE`LL PROB30 A TSTM OR TEMPO IT FOR KPHL
NORTH.
TONIGHT...VFR SCT-BKN CLOUDS AOA 6000 FT WITH A PERIOD OF SHOWERS
AND TSTMS VCNTY KABE AND KTTN AS STORMS DEVELOP NEAR THE SFC LOW
AND BOUNDARY OVER NRN PA AND MOVES RAPIDLY ESEWD WITH NW OUTFLOW
GUSTS OF 40-45 KT.
AGAIN...WE DONT KNOW IF CONVECTION CAN OCCUR.
OTHERWISE...PREVAILING SFC WINDS WILL BE LIGHT SW BUT THERE
SHOULD BE A SWD MOVING COLD FRONT WITH A WSHIFT TO N OR NE AFTER
06Z TONIGHT WITH VSBY LOWERING TO MVFR CONDS IN HAZE OR EVEN SCT-
BKN STRATUS BELOW 1000FT AFTER 09Z.
OUTLOOK...
THURSDAY...VFR TO MVFR. A CHANCE OF SOME SHOWERS PERHAPS EVOLVING
INTO SOME DRIZZLE, ESPECIALLY ALONG AND NORTH OF A FRONT THAT
SHOULD SETTLE SOUTHWARD ACROSS THE AREA. AS THIS OCCURS, AN
EASTERLY WIND SHOULD TAKE OVER WITH DEVELOPING LOWER CEILINGS FROM
NORTH TO SOUTH. OUR CONFIDENCE IS ON THE LOWER SIDE REGARDING THE
EXTENT AND TIMING OF THE LOW CLOUDS. THE WIND DIRECTION COULD BE
TRICKY FOR A TIME, BUT GENERALLY TURNING EASTERLY 10-15 KNOTS FROM
NORTH TO SOUTH.
THURSDAY NIGHT AND FRIDAY...SUB-VFR WITH SHOWERS AND A CHANCE OF
THUNDERSTORMS. THE RAIN MAY BE HEAVY AT TIMES, ESPECIALLY LATE
THURSDAY NIGHT AND FRIDAY MORNING. EAST WINDS 10-20 KNOTS PROBABLY
TURN SOUTHERLY FOR A TIME FRIDAY, THEN BECOMING WESTERLY LATE
FRIDAY.
FRIDAY NIGHT THROUGH SUNDAY...MAINLY VFR. WEST-NORTHWEST WINDS
GENERALLY 10-20 KNOTS.
&&
.MARINE...
NO HEADLINES EXPECTED THROUGH TONIGHT.
SW WINDS UNDER 20 KT SHOULD TURN WLY OVER THE S NJ AND DE WATERS
THIS MORNING WHILE AN ESE SEABREEZE DEVELOPS THIS MORNING IN
MONMOUTH COUNTY AND POSSIBLY OCEAN COUNTY NJ.
TONIGHT WINDS EVENTUALLY TURN N OR NE LATE BUT SPEEDS UNDER 20
KT.
SEAS AT OR BELOW 4 FT ON THE ATLC AND BELOW 3 FT ON DE BAY.
A GUSTY TSTM CANNOT BE RULED OUT LATE THIS AFTN OR EVENING OVER
THE NNJ WATERS.
OUTLOOK...
A FRONTAL BOUNDARY IS FORECAST TO SETTLE SOUTHWARD ACROSS THE
AREA THURSDAY. THIS WILL TEND TO SET UP AN EASTERLY FLOW THURSDAY
INTO FRIDAY, WHEN THE WINDS TURN SOUTHERLY AHEAD OF A COLD FRONT.
THE WINDS THEN BECOME WESTERLY LATER FRIDAY BEHIND THE FRONT. A
COLD FRONT FROM THE NORTH WILL PUSH INTO OUR REGION ON THURSDAY.
THE EASTERLY FLOW IS EXPECTED TO INCREASE, HOWEVER IT SHOULD HOLD
UNDER 25 KNOTS THURSDAY INTO FRIDAY. THE SEAS HOWEVER MAY REACH OR
EXCEED 5 FEET ON THE OCEAN ZONES THURSDAY INTO FRIDAY NIGHT. HIGH
PRESSURE GRADUALLY BUILDS IN OVER THE WEEKEND WITH WEST-NORTHWEST
WINDS TO AROUND 20 KNOTS SATURDAY INTO SUNDAY, THEN DIMINISHING
SOME AND BECOMING SOUTHWESTERLY LATE SUNDAY.
&&
.FIRE WEATHER...
THERE IS A VERY MARGINAL CONCERN FOR AN INCREASED RISK OF WILDFIRE
SPREAD DURING THE MID TO LATE AFTERNOON HOURS IN SOUTHERN NEW
JERSEY AND IN SOUTHERN DELAWARE. RELATIVE HUMIDITY VALUES MAY FALL
TO AROUND 35 PERCENT WITH A FEW WIND GUSTS NEAR 20 MPH. NO SPECIAL
WEATHER STATEMENT WILL BE ISSUED DUE TO THE VERY MARGINAL NATURE
OF THIS AFTERNOON`S FIRE WEATHER CONDITIONS.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR TODAY. THE RECORD HIGH FOR THURSDAY
IS ALSO INCLUDED FOR GEORGETOWN, DELAWARE.
ATLANTIC CITY.........85 IN 1922.
PHILADELPHIA..........87 IN 1922.
WILMINGTON............84 IN 1922.
ALLENTOWN.............85 IN 1922.
TRENTON...............83 IN 1922.
GEORGETOWN............82 IN 1991 (TODAY) AND 79 IN 2011 (THURS).
READING...............85 IN 1922.
MOUNT POCONO..........77 IN 1922.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...IOVINO
SHORT TERM...DRAG
LONG TERM...GORSE
AVIATION...DRAG/GORSE
MARINE...DRAG/GORSE
FIRE WEATHER...IOVINO
CLIMATE...GIGI/DRAG
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
945 AM EDT WED APR 10 2013
.SYNOPSIS...
A FRONTAL BOUNDARY DRAPED FROM OHIO THEN ACROSS NORTHERN
PENNSYLVANIA TO THE WATERS OFF NEW JERSEY WILL REMAIN NEARLY
STATIONARY INTO TONIGHT. THIS FRONT THEN SETTLES SOUTHWARD ACROSS
THE REGION LATE TONIGHT AND THURSDAY. A LOW PRESSURE SYSTEM IS
FORECAST TO TRACK ACROSS THE EASTERN GREAT LAKES REGION THURSDAY
NIGHT AND FRIDAY, WITH A WEAK LOW POSSIBLY DEVELOPING ALONG THE
COLD FRONT. THE ACTUAL COLD FRONT THEN SWEEPS ACROSS OUR AREA
LATER FRIDAY. HIGH PRESSURE GRADUALLY BUILDS IN OVER THE WEEKEND
BEFORE SHIFTING OFFSHORE INTO MONDAY. THE NEXT COLD FRONT SHOULD
APPROACH FROM THE WEST DURING TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE FRONTAL BOUNDARY EXTENDED ACROSS NORTHEASTERN BERKS COUNTY TO
AROUND NORTHEAST PHILADELPHIA THEN OFF THE NEW JERSEY COAST AROUND
POINT PLEASANT AND SEASIDE HEIGHTS AT 900 AM. THE BOUNDARY MAY
LIFT NORTHWARD A BIT DURING THE DAYLIGHT HOURS. THE SKY WAS MAINLY
CLEAR OVER OUR REGION TO THE SOUTH OF THE BOUNDARY WITH A PARTLY
CLOUDY SKY TO THE NORTH.
IT APPEARS AS THOUGH TEMPERATURES WILL SOAR INTO THE MIDDLE AND
UPPER 80S TO THE SOUTH OF THE PENNSYLVANIA TURNPIKE AND INTERSTATE
195 TODAY WITH A GOOD AMOUNT OF SUNSHINE. READINGS MAY BE A BIT
LOWER RIGHT ALONG THE COAST. THE FRONTAL BOUNDARY SHOULD KEEP
TEMPERATURES A BIT COOLER ACROSS THE NORTHERN HALF OF OUR FORECAST
AREA. MAXIMUM READINGS ARE ANTICIPATED TO BE AROUND 80 THERE WITH
TEMPERATURES REACHING ONLY THE MIDDLE 70S IN THE ELEVATED TERRAIN.
THE LATEST HRRR KEEPS OUR FORECAST AREA PRECIPITATION FREE UNTIL
600 PM. THE 0600 UTC NAM AND THE 0600 UTC GFS ARE ABOUT AN HOUR OR
TWO FASTER THAN THE HRRR. THE SREF ALSO LEANS TOWARD AN EARLIER
SOLUTION. THERE REMAINS SOME CONCERN THAT THE MODELS ARE
OVERPLAYING THE LOW LEVEL MOISTURE FOR THIS AFTERNOON. REGARDLESS,
WE CONTINUE TO EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO
BUILD ACROSS THE NORTHERN HALF OF OUR FORECAST AREA DURING THE
LATE AFTERNOON.
THE STORM PREDICTION CENTER HAS MUCH OF OUR FORECAST AREA UNDER
THEIR SLIGHT RISK FOR SEVERE WEATHER DESIGNATION FOR TODAY. WE
WILL CONTINUE TO MONITOR THE STABILITY PARAMETERS AS THE LATE
MORNING AND EARLY AFTERNOON PROGRESS, AS WELL AS THE TRENDS IN
CONVECTIVE DEVELOPMENT UPSTREAM.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
FCST PROBLEMS ARE THE SWD PROGRESSION OF THE BACKDOOR...THE UKMET
BEING MUCH FURTHER N THAN THE RGEM/NAM AND NOW THE MUCH FURTHER
SOUTH 00Z/10 GFS.
AND THE OTHER FCST PROBLEM...ANY SVR CONVECTION THIS EVENING.
AT THE LAST MINUTE JUST BEFORE THE 330AM FCST RELEASE I BOOSTED
POPS IN E PA AND NJ TONIGHT FOR AN OPPORTUNITY OF ESEWD MOVING BOW
ECHO OUT OF NRN PA FOR THE LEHIGH VALLEY AND CENTRAL NJ.
THE RECEIPT OF THE 06Z/10 HPC QPF FCST AND THE 00Z/10 ECMWF MASS
FIELDS AND QPF LOCKED ME INTO A 4-6 HOUR WINDOW OF OPPORTUNITY FOR
HEAVY CONVECTION. LOOK WHAT HAPPENED EARLY THIS MORNING...KISP 31
KTS AT 0747Z WITH 45 KT 0-6KM MODELED BULK SHEAR AND NO ML CAPE
NEARBY.
I THINK THIS COULD BE BUSY EVENING WITH POTENTIAL FOR SCT
DAMAGING WIND GUSTS BETWEEN I-80 AND I76-I195.
TEMPS: 50 50 BLEND OF THE 00Z/10 GFS/NAM MOS 3HRLY TEMPS FOR THE
LOW.
DEWPOINTS: 50 50 BLENDED 00Z/10 GFS/NAM MOS GUIDANCE.
WINDS: AN EQUAL BLEND OF THE 00Z/10 GFS/NAM MOS WITH THE 2M WINDS
OF THE RGEM/NAM. THAT MEANS CHILLING OCEAN BREEZES DEVELOP THE NNJ
COASTAL WATERS SOMETIME LATE THIS MORNING.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
THE OVERALL SYNOPTIC SETUP IS COMPRISED OF RIDGING ALONG THE MID
ATLANTIC COAST THURSDAY WITH A STRONG TROUGH FROM THE MIDWEST TO
THE LOWER MISSISSIPPI VALLEY. THIS FEATURE WILL BE THE MAIN ONE AS
WE GO THROUGH LATE THURSDAY AND FRIDAY, THEN WE TRANSITION BACK
INTO A TROUGH ACROSS THE NORTHEAST OVER THE WEEKEND, HOWEVER SOME
RIDGING LOOKS TO ARRIVE EARLY NEXT WEEK. THE MAIN FORECAST
CHALLENGES ARE CENTERED ON A BACKDOOR FRONT SETTLING SOUTH ACROSS
THE AREA THURSDAY, WHICH COULD RESULT IN A SIGNIFICANT TEMPERATURE
GRADIENT FROM SOUTH TO NORTH, THEN A STRONG COLD FRONT LATER
FRIDAY. THERE IS LOWER CONFIDENCE WITH TEMPERATURES THURSDAY AS
THE PLACEMENT OF THE BOUNDARY WILL BE CRUCIAL AS AN ONSHORE FLOW
IS NORTH OF IT. WE GENERALLY USED A BLEND OF MODEL GUIDANCE AND
CONTINUITY THURSDAY THROUGH SATURDAY, THEN BLENDED IN SOME OF THE
NEW WPC GUIDANCE WITH CONTINUITY THEREAFTER.
FOR THURSDAY...A TRICKY FORECAST REGARDING THE DETAILS AS A
FRONTAL BOUNDARY DRAPED EAST TO WEST IS FORECAST TO SETTLE
SOUTHWARD AS A BACKDOOR COLD FRONT. THE SOUTHWARD PROGRESSION OF
THIS FRONT MAY BE ENHANCED SOME BY SHOWERS AND/OR ELEVATED
CONVECTION TO ITS NORTH. THIS WILL ALSO HELP TO STRENGTHEN THE
THERMAL GRADIENT ALONG IT. THE MODEL GUIDANCE IN GENERAL SEEMS TO
BE SENDING THIS LOW-LEVEL FRONT A BIT FARTHER SOUTH, WHICH TURNS
THE SURFACE WINDS OUT OF THE EAST AND NORTHEAST. THIS WOULD RESULT
IN LOW CLOUDS AND PERHAPS SOME LIGHT RAIN OR DRIZZLE. THERE WILL
LIKELY BE A SIGNIFICANT TEMPERATURE GRADIENT WITH THIS BOUNDARY,
WHICH CAN LEAD TO A HIGH BUST POTENTIAL IN THE TEMPERATURE
DEPARTMENT. HOWEVER, THE STRONGEST LIFT LOOKS TO BE MOSTLY NORTH
OF OUR AREA. THIS WOULD POINT TO A MORE LIGHT RAIN OR DRIZZLE TYPE
SCENARIO AS THE EASTERLY FLOW SETS UP AND THE LOW-LEVEL MOISTURE
DEEPENS BENEATH AN INVERSION.
WE THEREFORE USED A BLEND OF THE NAM/GFS MOS WITH SOME
INCORPORATION OF THE ECMWF. THIS SEEMS TO DEPICT A DECENT DOWNWARD
TREND THAT WE ARE SEEING REGARDING HIGH TEMPERATURES. AS MENTIONED
THERE IS A BUST POTENTIAL WITH THIS AS SOUTH OF THE FRONT IT WILL
BE RATHER WARM. TEMPERATURES MAY ACTUALLY FALL SOME DURING THE DAY
NORTH OF THE FRONT AS THE LOW-LEVEL CAA OCCURS WITHIN AN EASTERLY
FLOW. WE MAINTAINED SLIGHT CHC TO CHC POPS GRADUALLY FROM NORTH TO
SOUTH DURING THE DAY WITH SHOWER WORDING TRANSITIONING OVER TO
RAIN/DRIZZLE TOWARD EVENING ACROSS THE NORTHEASTERN PART OF THE
CWA. THIS IS DUE TO THE ONSHORE FLOW AND COOLING FORECAST TO TAKE
PLACE. THERE COULD BE SOME FOG DEVELOPING AS WELL, DUE TO THE LOW-
LEVEL MOISTURE AND ONSHORE FLOW COMBINED WITH THE COOLER AIR
UNDERCUTTING THE WARMER AIR. HOWEVER, NOT CONFIDENT ON THE EXTENT
OF THIS, THEREFORE DID NOT INCLUDE ATTM.
AS WE GO THROUGH THURSDAY NIGHT, THE AFOREMENTIONED BACKDOOR
FRONT WILL PROBABLY TRY AND LIFT NORTHWARD AT LEAST SOME LATE AS
INCREASING WAA AND FLOW ARRIVES AHEAD OF THE NEXT SYSTEM. THIS
WILL BE LOW PRESSURE TRACKING TOWARD THE EASTERN GREAT LAKES
REGION. THERE IS PLENTY OF MOISTURE FORECAST TO SURGE AHEAD OF
THIS FEATURE ALONG WITH DECENT LARGE SCALE LIFT AND EVEN FRONTAL
FORCING. AS THE WARMER AND MORE MOIST AIR IS LIFTED OVER THE
EXISTING COOLER LOW-LEVEL AIRMASS OVER MUCH OF OUR AREA, AT LEAST
SOME ELEVATED INSTABILITY IS FORECAST. THIS COULD BE ENOUGH TO
GENERATE SOME THUNDERSTORMS FROM WEST TO EAST. THERE MAY BE STRONG
LINEAR FORCING AHEAD OF THE COLD/OCCLUDING FRONT TO RESULT IN A
NARROW CONVECTIVE LINE. WE GENERALLY MAINTAINED CONTINUITY WHICH
SHOWS POPS INCREASING TO LIKELY AND CATEGORICAL THROUGH THE NIGHT.
WE DID HOWEVER START WITH LIGHT RAIN/DRIZZLE WORDING THEN
TRANSITIONED OVER TO SHOWERS AS INCREASING ASCENT ARRIVES. IT IS
POSSIBLE THAT TEMPERATURES RISE SOME ACROSS THE FAR SOUTHERN ZONES
LATE AS THE BOUNDARY STARTS TO SHIFT NORTHWARD AS A WARM FRONT.
FOR FRIDAY...A SURFACE LOW GENERALLY TRACKS UP ACROSS THE GREAT
LAKES REGION, THEN AN OCCLUDED FRONT ARRIVES INTO OUR AREA. THERE
COULD BE A WEAK LOW DEVELOPING AT THE TRIPLE POINT, AND THIS WILL
DETERMINE WHERE THE FRONT IS DRAPED THAT EVENTUALLY SHIFTS
NORTHWARD SOME AS A WARM FRONT. OUR ENTIRE AREA MAY GET INTO THE
SOUTHERLY FLOW AHEAD OF THE MAIN FRONT FOR A TIME DURING THE
AFTERNOON, HOWEVER THIS IS TRICKY WITH THE TIMING AND WILL LIKELY
HAVE AN IMPACT ON OUR TEMPERATURES. NORTH OF THE FRONT THERE WILL
BE LINGERING LOW-LEVEL EASTERLY WINDS KEEPING MOISTURE LOCKED IN,
THEREFORE IF WE CAN VEER THE WINDS TO MORE SOUTHERLY FAST ENOUGH
SOME ADDITIONAL WARMING PERHAPS OCCURS.
THE FORECAST SOUNDINGS SHOW A STRENGTHENING AND VEERING FLOW
BELOW 10,000 FEET FOR A TIME FRIDAY PRIOR TO THE COLD FRONTAL
PASSAGE. ASSUMING MUCH OF THE AREA IS UNDER AN EASTERLY FLOW FOR A
TIME, THE LOWER LEVELS WILL BE STABLE BUT SOME ELEVATED
INSTABILITY IS HINTED AT TO START THE DAY, BUT THEN INCREASING AT
LEAST SOME. THE DELMARVA MAY HAVE A BETTER CHC OF SEEING SURFACE
BASED INSTABILITY. THIS IN COMBINATION WITH THE LINEAR FORCING
WITH THE FRONT COULD RESULT IN SOME THUNDERSTORMS, WHICH COULD BE
IN THE FORM OF NARROW LINE SEGMENTS. SOME GUIDANCE SHOWING A
DECENT AMOUNT OF INSTABILITY WORKING IN ALONG WITH HIGHER SHEAR,
THEREFORE SOME STRONG/SEVERE CONVECTION CANNOT BE RULED OUT
ESPECIALLY IF WE CAN ERODE ANY STABLE LOW-LEVEL ENVIRONMENT. AS OF
NOW, WE HELD OFF ON ANY ENHANCED WORDING IN THE FORECAST WITH THIS
SYSTEM DUE TO DETAIL UNCERTAINTIES. THE PW VALUES HOWEVER ARE
FORECAST TO BE AROUND 1.5 INCHES AHEAD OF THE FRONT, THEREFORE
LOCALLY HEAVY RAINFALL WILL CERTAINLY BE POSSIBLE ESPECIALLY
FRIDAY MORNING. WE DID NOTE THE 00Z ECMWF IS A LITTLE SLOWER WITH
THE MAIN PRECIPITATION.
FOR SATURDAY AND SUNDAY...AN UPPER-LEVEL TROUGH WILL BE SETTLING
INTO THE NORTHEAST, AS A COLD FRONT IS EAST OF OUR AREA TO START
SATURDAY. THERE MAY BE A SECONDARY COOL FRONT OR SURFACE TROUGH
THAT SWINGS THROUGH LATE IN THE DAY SATURDAY, HOWEVER MOISTURE AND
FORCING LOOKS WEAK. OTHERWISE, A COOLER AIRMASS WILL BE IN PLACE
AS CAA OCCURS. HIGH PRESSURE SLIDING INTO THE UPPER OHIO VALLEY
SATURDAY WILL MAINTAIN A TIGHTER PRESSURE GRADIENT ACROSS OUR
AREA, THEREFORE A WESTERLY BREEZE IS ANTICIPATED. A STRONG SHORT
WAVE SLIDES ACROSS THE AREA SATURDAY NIGHT WITH PERHAPS A SHOWER
AROUND, ALTHOUGH THE AIRMASS MAY BE A LITTLE TO DRY. WE WILL KEEP
A DRY FORECAST ATTM.
HIGH PRESSURE SHOULD THEN BE TRANSITIONING TO OUR EAST DURING
SUNDAY. THIS WILL RESULT IN LESS WIND WITH TIME AND ALSO HELP WITH
THE WAA DEVELOPING UP THE OHIO VALLEY. THIS SHOULD HELP ORGANIZE A
WARM FRONT THAT LIFTS BY MOSTLY TO OUR NORTHWEST SUNDAY NIGHT.
SOME GUIDANCE SHOWS STRONG WAA AND ISENTROPIC UPGLIDE FARTHER
EAST, WHICH WOULD BRING SOME SHOWERS INTO PORTIONS OF OUR AREA.
THIS MAY BE OVERDONE, THEREFORE WE OPTED TO KEEP A DRY FORECAST
GOING ATTM.
FOR MONDAY AND TUESDAY...THE NEXT SYSTEM IS FORECAST TO TRACK
GENERALLY UP ACROSS THE GREAT LAKES LATE MONDAY AND TUESDAY. THIS
PLACES A WARM FRONT TO OUR NORTH, THEN THE ASSOCIATED COLD FRONT
ARRIVES AS WE GO THROUGH TUESDAY. THERE IS UNCERTAINTY WITH THE
TIMING AS SOME GUIDANCE IS MUCH FASTER WITH THE ARRIVAL OF THE
COLD FRONT. WE THEREFORE STAYED CLOSE TO CONTINUITY/WPC GUIDANCE
WHICH SHOWS A SLOWER ARRIVAL OF THE COLD FRONT. SLIGHT CHC OR LOW
CHC POPS REMAIN IN THE DATABASE MAINLY ALONG AND NORTH/WEST OF
INTERSTATE 95 MONDAY NIGHT AND TUESDAY. A WARMER AIRMASS WILL
ARRIVE AHEAD OF THE COLD FRONT, THEREFORE THIS IS REFLECTED IN THE
TEMPERATURES.
&&
.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY AND SURROUNDING AREAS.
TODAY...VFR WITH WESTERLY WIND GUSTS TO AROUND 20 KTS MIDDAY AND
THIS AFTN...POSSIBLY 25 KT IN DE. SCT TO BKN CLOUDS AOA 6000 FT. A
CHANCE OF A TSTM AFTER 20Z OVER E PA. CONFIDENCE ON CONVECTION IS
MUCH BELOW AVG DUE TO MOISTURE AVAILABILITY. IF CONVECTION
DEVELOPS IN W PA AND MOVES EAST...IT COULD BE ACCOMPANIED BY A NW
WIND GUST TO 45 KT BUT JUST DONT KNOW IF TSTMS CAN DEVELOP THIS
AFTN. THE POSSIBILITY OF STRONG TSTMS LATE TODAY NEEDS TO BE
MAINTAINED AS AN OPTION IN FLIGHT PREPARATIONS....PARTICULARLY IN
PA AND THE N/2RDS NJ. WE`LL PROB30 A TSTM OR TEMPO IT FOR KPHL
NORTH.
TONIGHT...VFR SCT-BKN CLOUDS AOA 6000 FT WITH A PERIOD OF SHOWERS
AND TSTMS VCNTY KABE AND KTTN AS STORMS DEVELOP NEAR THE SFC LOW
AND BOUNDARY OVER NRN PA AND MOVES RAPIDLY ESEWD WITH NW OUTFLOW
GUSTS OF 40-45 KT.
AGAIN...WE DONT KNOW IF CONVECTION CAN OCCUR.
OTHERWISE...PREVAILING SFC WINDS WILL BE LIGHT SW BUT THERE
SHOULD BE A SWD MOVING COLD FRONT WITH A WSHIFT TO N OR NE AFTER
06Z TONIGHT WITH VSBY LOWERING TO MVFR CONDS IN HAZE OR EVEN SCT-
BKN STRATUS BELOW 1000FT AFTER 09Z.
OUTLOOK...
THURSDAY...VFR TO MVFR. A CHANCE OF SOME SHOWERS PERHAPS EVOLVING
INTO SOME DRIZZLE, ESPECIALLY ALONG AND NORTH OF A FRONT THAT
SHOULD SETTLE SOUTHWARD ACROSS THE AREA. AS THIS OCCURS, AN
EASTERLY WIND SHOULD TAKE OVER WITH DEVELOPING LOWER CEILINGS FROM
NORTH TO SOUTH. OUR CONFIDENCE IS ON THE LOWER SIDE REGARDING THE
EXTENT AND TIMING OF THE LOW CLOUDS. THE WIND DIRECTION COULD BE
TRICKY FOR A TIME, BUT GENERALLY TURNING EASTERLY 10-15 KNOTS FROM
NORTH TO SOUTH.
THURSDAY NIGHT AND FRIDAY...SUB-VFR WITH SHOWERS AND A CHANCE OF
THUNDERSTORMS. THE RAIN MAY BE HEAVY AT TIMES, ESPECIALLY LATE
THURSDAY NIGHT AND FRIDAY MORNING. EAST WINDS 10-20 KNOTS PROBABLY
TURN SOUTHERLY FOR A TIME FRIDAY, THEN BECOMING WESTERLY LATE
FRIDAY.
FRIDAY NIGHT THROUGH SUNDAY...MAINLY VFR. WEST-NORTHWEST WINDS
GENERALLY 10-20 KNOTS.
&&
.MARINE...
NO HEADLINES EXPECTED THROUGH TONIGHT.
SW WINDS UNDER 20 KT SHOULD TURN WLY OVER THE S NJ AND DE WATERS
THIS MORNING WHILE AN ESE SEABREEZE DEVELOPS THIS MORNING IN
MONMOUTH COUNTY AND POSSIBLY OCEAN COUNTY NJ.
TONIGHT WINDS EVENTUALLY TURN N OR NE LATE BUT SPEEDS UNDER 20
KT.
SEAS AT OR BELOW 4 FT ON THE ATLC AND BELOW 3 FT ON DE BAY.
A GUSTY TSTM CANNOT BE RULED OUT LATE THIS AFTN OR EVENING OVER
THE NNJ WATERS.
OUTLOOK...
A FRONTAL BOUNDARY IS FORECAST TO SETTLE SOUTHWARD ACROSS THE
AREA THURSDAY. THIS WILL TEND TO SET UP AN EASTERLY FLOW THURSDAY
INTO FRIDAY, WHEN THE WINDS TURN SOUTHERLY AHEAD OF A COLD FRONT.
THE WINDS THEN BECOME WESTERLY LATER FRIDAY BEHIND THE FRONT. A
COLD FRONT FROM THE NORTH WILL PUSH INTO OUR REGION ON THURSDAY.
THE EASTERLY FLOW IS EXPECTED TO INCREASE, HOWEVER IT SHOULD HOLD
UNDER 25 KNOTS THURSDAY INTO FRIDAY. THE SEAS HOWEVER MAY REACH OR
EXCEED 5 FEET ON THE OCEAN ZONES THURSDAY INTO FRIDAY NIGHT. HIGH
PRESSURE GRADUALLY BUILDS IN OVER THE WEEKEND WITH WEST-NORTHWEST
WINDS TO AROUND 20 KNOTS SATURDAY INTO SUNDAY, THEN DIMINISHING
SOME AND BECOMING SOUTHWESTERLY LATE SUNDAY.
&&
.FIRE WEATHER...
HIGH RH THAN YDY BUT IT MAY STILL LOWER TO NEAR 30 PCT THIS AFTN
WITH WESTERLY WIND GUSTS TO 20 MPH. WE`LL COORDINATE DURING THE
DAYLIGHT HOURS WITH OUR FWX PARTNERS. THE DEW POINT FCST IS
UNCERTAIN FOR THIS AFTN AND AM THINKING OUR FCST DEWPOINTS ARE TOO
HIGH. WE`LL REREVIEW DURING MID MORNING.
&&
.CLIMATE...
RECORD HIGH TEMPERATURES FOR TODAY. THE RECORD HIGH FOR THURSDAY
IS ALSO INCLUDED FOR GEORGETOWN, DELAWARE.
ATLANTIC CITY.........85 IN 1922.
PHILADELPHIA..........87 IN 1922.
WILMINGTON............84 IN 1922.
ALLENTOWN.............85 IN 1922.
TRENTON...............83 IN 1922.
GEORGETOWN............82 IN 1991 (TODAY) AND 79 IN 2011 (THURS).
READING...............85 IN 1922.
MOUNT POCONO..........77 IN 1922.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...IOVINO
SHORT TERM...DRAG
LONG TERM...GORSE
AVIATION...DRAG/GORSE
MARINE...DRAG/GORSE
FIRE WEATHER...DRAG
CLIMATE...GIGI/DRAG
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1045 AM CDT WED APR 10 2013
.DISCUSSION...
ISSUED 1037 AM CDT WED APR 10 2013
DENSE COLD AIR FROM OVERNIGHT CONVECTION PUSHING A BOUNDARY SOUTH
ACROSS THE AREA WITH A 20-30 DEGREE DROP AS THE BOUNDARY
PASSES. WAA ON THE SOUTH SIDE OF THE BOUNDARY STARTING TO KICK IN
WITH SOUTHERLY WINDS PICKING UP SLIGHTLY. SHOWERS AHEAD AND BEHIND
THE BOUNDARY...WITH THE MORE EXPANSIVE THUNDERSTORMS JUST BEHIND
THE FRONT APPROACHING FROM THE SW. REMAINING FORECAST VERY
DEPENDENT ON WHICH AIRMASS WILL OVERCOME THE OTHER...AND HOW FAR
THAT BOUNDARY WILL TRAVEL. ILX CWA ROUGHLY CUT IN HALF BY A VERY
DISTINCTIVE BOUNDARY WITH CHILLY TEMPS ON ONE SIDE...AND
UNSEASONABLY WARM ON THE OTHER. CHANCES FOR SHOWERS AND
THUNDERSTORMS DEVELOPING AND SPREADING AS THE AFTERNOON PROGRESSES
REMAIN AS PLENTY OF ACTIVITY LINES UP ALONG THE FRONT. OVERALL
CHANGES TO THE FORECAST MINIMAL. HAVE UPDATED GRIDS FOR HOURLY
TRENDS AND WILL REISSUE THE ZONES FOR MORNING WORDING.
HJS
&&
.AVIATION...
ISSUED 659 AM CDT WED APR 10 2013
12Z TAF FORECAST FOR THE CENTRAL ILLINOIS WILL PROVE TO BE RATHER
COMPLICATED. A BROKEN BAND OF SHOWERS AND THUNDERSTORMS IS
BEGINNING TO PUSH EAST ACROSS THE AREA...AND WOULD ONLY RESULT IN
A BRIEF REDUCTION BELOW VFR AS THEY MOVE THROUGH. HOWEVER...AN
OUTFLOW BOUNDARY FROM A LARGER AREA OF CONVECTION OVER NORTHERN
ILLINOIS HAS RESULTED IN TEMPORARILY STRONG NORTHERLY WINDS IN ITS
WAKE...AS WELL AS IFR CIGS. SO FAR THE OUTFLOW BOUNDARY HAS ONLY
IMPACTED KPIA...BUT KBMI AND KSPI APPEAR LIKELY TO BE IMPACTED
SHORTLY. ONCE THE BROKEN BAND OF SHOWERS/STORMS MOVES THROUGH MUCH
OF THE DAY SHOULD BE DRY WITH VFR/MVFR CIGS. SHOWER/STORMS WILL
BECOME MORE WIDESPREAD LATE THIS AFTERNOON INTO TONIGHT AND THE
PRECIPITATION SHOULD EVENTUALLY RESULT IN WIDESPREAD IFR
CONDITIONS. WIND DIRECTION MAY BE RATHER VARIABLE TODAY DUE TO THE
CONVECTION AND ASSOCIATED OUTFLOWS. OUTSIDE OF STORMS...SOUTHERLY
FLOW AT KSPI/KDEC/KCMI AND EASTERLY FLOW AT KPIA/KBMI WILL TREND
SOUTHWESTERLY LATE AS A COLD FRONT PUSHES THROUGH THE AREA.
BAK
&&
.PREV DISCUSSION...
ISSUED 300 AM CDT WED APR 10 2013
FRONTAL BOUNDARY WAS DRAPED ACROSS ABOUT THE NORTHERN THIRD OF
THE FORECAST AREA AT 3 AM...ROUGHLY ALONG A MACOMB TO BLOOMINGTON
LINE...WITH THE BOUNDARY EXTENDING WESTWARD TO A LOW IN WESTERN
MISSOURI. WIDESPREAD 60S PREVAILING TO THE SOUTH OF IT...WITH A
QUICK DROP OFF INTO THE 40S AND 50S NORTH OF IT. REGIONAL RADAR
MOSAICS SHOWING SEVERAL MCS CLUSTERS FROM WISCONSIN SOUTHWEST TO
NORTHERN TEXAS. A SIGNIFICANT MAJORITY OF THESE STORMS WAS
ELEVATED...WITH NORTHEAST SURFACE WINDS AND TEMPS IN THE 30S AND
40S.
THERE ARE TWO MAIN FOCUSES FOR TODAY...INVOLVING THE TRACK OF THIS
FRONT WITH ITS IMPACTS ON TEMPERATURES...AS WELL AS RISK OF
SEVERE WEATHER THIS AFTERNOON AND TONIGHT. LONGER TERM CONCERNS
INVOLVE RAIN CHANCES LATE IN THE WEEKEND AND EARLY NEXT WEEK.
SHORT TERM...TODAY THROUGH FRIDAY...
MOST OF THE MODEL GUIDANCE DOES NOT SHOW MUCH FURTHER SOUTHWARD
PROGRESSION WITH THE BOUNDARY TODAY...WITH THE GFS THE FURTHEST
SOUTH REACHING ABOUT I-72. QUESTION WILL BE WHETHER OR NOT THE
EXISTING CONVECTION PUSHES THE EFFECTIVE BOUNDARY FURTHER SOUTH
THAN THE MODELS ARE PROJECTING. THE GRIDS FOR TODAY WILL SHOW THE
BOUNDARY BASICALLY STATIONARY...THEN PUSHING NORTHWARD THIS
EVENING AS THE SURFACE LOW TRACKS TOWARD NORTHWEST ILLINOIS. NORTH
OF THIS FRONT...HIGHS WILL ONLY BE IN THE 50S ACROSS THE EXTREME
NORTHERN CWA...WITH WIDESPREAD 70S TO THE SOUTH.
LATEST SPC CONVECTIVE OUTLOOK MAINTAINS SLIGHT CHANCES OF SEVERE
WEATHER...MAINLY THIS AFTERNOON AND TONIGHT. SIGNIFICANT CAP
SHOULD ERODE BY LATE MORNING AS MU-CAPES RISE TO AROUND 1500
J/KG...AND 0-6KM BULK SHEAR INCREASES TO AROUND 40-45 KNOTS BY
LATE AFTERNOON. MAIN LINE OF STRONG TO SEVERE STORMS EXPECTED TO
DEVELOP ACROSS MISSOURI DURING THE AFTERNOON AND TREK
EASTWARD...BUT RAP AND NAM DO SHOW SOME WEAKER CONVECTION
IMMEDIATELY ALONG OUR BOUNDARY AT TIMES AS WELL. WIND DAMAGE
SHOULD BE THE MAIN THREAT IN OUR AREA AS THE CONVECTION ORGANIZES
INTO A LINEAR MCS TO OUR WEST...BUT SOME LARGE HAIL WILL ALSO BE
POSSIBLE...ESPECIALLY IF ANYTHING FORMS AHEAD OF THE MAIN LINE.
PRECIPITABLE WATER VALUES PROGGED TO BE AROUND 1.4 TO 1.5 INCHES
THROUGH TONIGHT...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE
NORMAL FOR THIS TIME OF YEAR...SO WILL LIKELY SEE SOME HEAVIER
RAINS WITH THE STORMS AS WELL.
THE COLD FRONT TRAILING THE LOW SHOULD CROSS THE INDIANA BORDER
EARLY THURSDAY MORNING...TAKING MOST OF THE RAIN WITH IT. HAVE
LINGERED SOME LIKELY POPS ALONG THE BORDER FOR THE MORNING...BUT
DRY SLOT WILL BE WORKING ITS WAY ACROSS MOST OF THE AREA. HAVE NOT
COMPLETELY REMOVED THE RAIN CHANCES THOUGH...AS THE UPPER LOW
MOVES ACROSS IOWA AND POTENTIALLY BRINGS SOME SHOWERS THIS FAR
SOUTHEAST...ESPECIALLY IN THE NORTHERN CWA. TEMPERATURES NOT
EXPECTED TO DO MUCH AND WILL BE WARMEST IN THE EAST...AS IT WILL
TAKE MOST OF THE DAY FOR 850 MB TEMPS TO FALL BELOW ZERO THAT FAR
EAST.
LONG TERM...SATURDAY THROUGH TUESDAY...
UPPER LOW EXPECTED TO SLOWLY WEAKEN AS IT LIFTS INTO THE GREAT
LAKES REGION LATE THIS WEEK. BOTH THE GFS AND ECMWF MODELS TRY TO
ESTABLISH SOME SORT OF ZONAL FLOW THIS WEEKEND...WITH ANOTHER LOW
RIDING EASTWARD ALONG THE CANADIAN BORDER INTO NORTH DAKOTA BEFORE
DIGGING A TROUGH WEST OF THE ROCKIES. MAINLY DRY CONDITIONS ARE
EXPECTED THE FIRST HALF OF THE WEEKEND. BY SATURDAY NIGHT...A
SHORTWAVE WILL BE MOVING THROUGH THE PLAINS. THE TWO MODELS DO NOT
HANDLE THIS TRANSITION WELL...WITH THE ECMWF SLOWER AND STRONGER
WITH THE SECOND UPPER LOW AND THUS KEEPING US IN THE WARM SECTOR
LONGER...WHILE THE GFS DRAPES A WARM FRONT OVER CENTRAL ILLINOIS.
HOWEVER...EVENTUALLY THE TWO PHASE THE SURFACE FEATURES BETTER BY
MONDAY. WILL HAVE RAIN CHANCES MENTIONED FROM SUNDAY THROUGH
TUESDAY.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
659 AM CDT WED APR 10 2013
.DISCUSSION...
ISSUED 300 AM CDT WED APR 10 2013
FRONTAL BOUNDARY WAS DRAPED ACROSS ABOUT THE NORTHERN THIRD OF
THE FORECAST AREA AT 3 AM...ROUGHLY ALONG A MACOMB TO BLOOMINGTON
LINE...WITH THE BOUNDARY EXTENDING WESTWARD TO A LOW IN WESTERN
MISSOURI. WIDESPREAD 60S PREVAILING TO THE SOUTH OF IT...WITH A
QUICK DROP OFF INTO THE 40S AND 50S NORTH OF IT. REGIONAL RADAR
MOSAICS SHOWING SEVERAL MCS CLUSTERS FROM WISCONSIN SOUTHWEST TO
NORTHERN TEXAS. A SIGNIFICANT MAJORITY OF THESE STORMS WAS
ELEVATED...WITH NORTHEAST SURFACE WINDS AND TEMPS IN THE 30S AND
40S.
THERE ARE TWO MAIN FOCUSES FOR TODAY...INVOLVING THE TRACK OF THIS
FRONT WITH ITS IMPACTS ON TEMPERATURES...AS WELL AS RISK OF
SEVERE WEATHER THIS AFTERNOON AND TONIGHT. LONGER TERM CONCERNS
INVOLVE RAIN CHANCES LATE IN THE WEEKEND AND EARLY NEXT WEEK.
SHORT TERM...TODAY THROUGH FRIDAY...
MOST OF THE MODEL GUIDANCE DOES NOT SHOW MUCH FURTHER SOUTHWARD
PROGRESSION WITH THE BOUNDARY TODAY...WITH THE GFS THE FURTHEST
SOUTH REACHING ABOUT I-72. QUESTION WILL BE WHETHER OR NOT THE
EXISTING CONVECTION PUSHES THE EFFECTIVE BOUNDARY FURTHER SOUTH
THAN THE MODELS ARE PROJECTING. THE GRIDS FOR TODAY WILL SHOW THE
BOUNDARY BASICALLY STATIONARY...THEN PUSHING NORTHWARD THIS
EVENING AS THE SURFACE LOW TRACKS TOWARD NORTHWEST ILLINOIS. NORTH
OF THIS FRONT...HIGHS WILL ONLY BE IN THE 50S ACROSS THE EXTREME
NORTHERN CWA...WITH WIDESPREAD 70S TO THE SOUTH.
LATEST SPC CONVECTIVE OUTLOOK MAINTAINS SLIGHT CHANCES OF SEVERE
WEATHER...MAINLY THIS AFTERNOON AND TONIGHT. SIGNIFICANT CAP
SHOULD ERODE BY LATE MORNING AS MU-CAPES RISE TO AROUND 1500
J/KG...AND 0-6KM BULK SHEAR INCREASES TO AROUND 40-45 KNOTS BY
LATE AFTERNOON. MAIN LINE OF STRONG TO SEVERE STORMS EXPECTED TO
DEVELOP ACROSS MISSOURI DURING THE AFTERNOON AND TREK
EASTWARD...BUT RAP AND NAM DO SHOW SOME WEAKER CONVECTION
IMMEDIATELY ALONG OUR BOUNDARY AT TIMES AS WELL. WIND DAMAGE
SHOULD BE THE MAIN THREAT IN OUR AREA AS THE CONVECTION ORGANIZES
INTO A LINEAR MCS TO OUR WEST...BUT SOME LARGE HAIL WILL ALSO BE
POSSIBLE...ESPECIALLY IF ANYTHING FORMS AHEAD OF THE MAIN LINE.
PRECIPITABLE WATER VALUES PROGGED TO BE AROUND 1.4 TO 1.5 INCHES
THROUGH TONIGHT...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE
NORMAL FOR THIS TIME OF YEAR...SO WILL LIKELY SEE SOME HEAVIER
RAINS WITH THE STORMS AS WELL.
THE COLD FRONT TRAILING THE LOW SHOULD CROSS THE INDIANA BORDER
EARLY THURSDAY MORNING...TAKING MOST OF THE RAIN WITH IT. HAVE
LINGERED SOME LIKELY POPS ALONG THE BORDER FOR THE MORNING...BUT
DRY SLOT WILL BE WORKING ITS WAY ACROSS MOST OF THE AREA. HAVE NOT
COMPLETELY REMOVED THE RAIN CHANCES THOUGH...AS THE UPPER LOW
MOVES ACROSS IOWA AND POTENTIALLY BRINGS SOME SHOWERS THIS FAR
SOUTHEAST...ESPECIALLY IN THE NORTHERN CWA. TEMPERATURES NOT
EXPECTED TO DO MUCH AND WILL BE WARMEST IN THE EAST...AS IT WILL
TAKE MOST OF THE DAY FOR 850 MB TEMPS TO FALL BELOW ZERO THAT FAR
EAST.
LONG TERM...SATURDAY THROUGH TUESDAY...
UPPER LOW EXPECTED TO SLOWLY WEAKEN AS IT LIFTS INTO THE GREAT
LAKES REGION LATE THIS WEEK. BOTH THE GFS AND ECMWF MODELS TRY TO
ESTABLISH SOME SORT OF ZONAL FLOW THIS WEEKEND...WITH ANOTHER LOW
RIDING EASTWARD ALONG THE CANADIAN BORDER INTO NORTH DAKOTA BEFORE
DIGGING A TROUGH WEST OF THE ROCKIES. MAINLY DRY CONDITIONS ARE
EXPECTED THE FIRST HALF OF THE WEEKEND. BY SATURDAY NIGHT...A
SHORTWAVE WILL BE MOVING THROUGH THE PLAINS. THE TWO MODELS DO NOT
HANDLE THIS TRANSITION WELL...WITH THE ECMWF SLOWER AND STRONGER
WITH THE SECOND UPPER LOW AND THUS KEEPING US IN THE WARM SECTOR
LONGER...WHILE THE GFS DRAPES A WARM FRONT OVER CENTRAL ILLINOIS.
HOWEVER...EVENTUALLY THE TWO PHASE THE SURFACE FEATURES BETTER BY
MONDAY. WILL HAVE RAIN CHANCES MENTIONED FROM SUNDAY THROUGH
TUESDAY.
GEELHART
&&
.AVIATION...
ISSUED 659 AM CDT WED APR 10 2013
12Z TAF FORECAST FOR THE CENTRAL ILLINOIS WILL PROVE TO BE RATHER
COMPLICATED. A BROKEN BAND OF SHOWERS AND THUNDERSTORMS IS
BEGINNING TO PUSH EAST ACROSS THE AREA...AND WOULD ONLY RESULT IN
A BRIEF REDUCTION BELOW VFR AS THEY MOVE THROUGH. HOWEVER...AN
OUTFLOW BOUNDARY FROM A LARGER AREA OF CONVECTION OVER NORTHERN
ILLINOIS HAS RESULTED IN TEMPORARILY STRONG NORTHERLY WINDS IN ITS
WAKE...AS WELL AS IFR CIGS. SO FAR THE OUTFLOW BOUNDARY HAS ONLY
IMPACTED KPIA...BUT KBMI AND KSPI APPEAR LIKELY TO BE IMPACTED
SHORTLY. ONCE THE BROKEN BAND OF SHOWERS/STORMS MOVES THROUGH MUCH
OF THE DAY SHOULD BE DRY WITH VFR/MVFR CIGS. SHOWER/STORMS WILL
BECOME MORE WIDESPREAD LATE THIS AFTERNOON INTO TONIGHT AND THE
PRECIPITATION SHOULD EVENTUALLY RESULT IN WIDESPREAD IFR
CONDITIONS. WIND DIRECTION MAY BE RATHER VARIABLE TODAY DUE TO THE
CONVECTION AND ASSOCIATED OUTFLOWS. OUTSIDE OF STORMS...SOUTHERLY
FLOW AT KSPI/KDEC/KCMI AND EASTERLY FLOW AT KPIA/KBMI WILL TREND
SOUTHWESTERLY LATE AS A COLD FRONT PUSHES THROUGH THE AREA.
BAK
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
300 AM CDT WED APR 10 2013
.DISCUSSION...
ISSUED 300 AM CDT WED APR 10 2013
FRONTAL BOUNDARY WAS DRAPED ACROSS ABOUT THE NORTHERN THIRD OF
THE FORECAST AREA AT 3 AM...ROUGHLY ALONG A MACOMB TO BLOOMINGTON
LINE...WITH THE BOUNDARY EXTENDING WESTWARD TO A LOW IN WESTERN
MISSOURI. WIDESPREAD 60S PREVAILING TO THE SOUTH OF IT...WITH A
QUICK DROP OFF INTO THE 40S AND 50S NORTH OF IT. REGIONAL RADAR
MOSAICS SHOWING SEVERAL MCS CLUSTERS FROM WISCONSIN SOUTHWEST TO
NORTHERN TEXAS. A SIGNIFICANT MAJORITY OF THESE STORMS WAS
ELEVATED...WITH NORTHEAST SURFACE WINDS AND TEMPS IN THE 30S AND
40S.
THERE ARE TWO MAIN FOCUSES FOR TODAY...INVOLVING THE TRACK OF THIS
FRONT WITH ITS IMPACTS ON TEMPERATURES...AS WELL AS RISK OF
SEVERE WEATHER THIS AFTERNOON AND TONIGHT. LONGER TERM CONCERNS
INVOLVE RAIN CHANCES LATE IN THE WEEKEND AND EARLY NEXT WEEK.
SHORT TERM...TODAY THROUGH FRIDAY...
MOST OF THE MODEL GUIDANCE DOES NOT SHOW MUCH FURTHER SOUTHWARD
PROGRESSION WITH THE BOUNDARY TODAY...WITH THE GFS THE FURTHEST
SOUTH REACHING ABOUT I-72. QUESTION WILL BE WHETHER OR NOT THE
EXISTING CONVECTION PUSHES THE EFFECTIVE BOUNDARY FURTHER SOUTH
THAN THE MODELS ARE PROJECTING. THE GRIDS FOR TODAY WILL SHOW THE
BOUNDARY BASICALLY STATIONARY...THEN PUSHING NORTHWARD THIS
EVENING AS THE SURFACE LOW TRACKS TOWARD NORTHWEST ILLINOIS. NORTH
OF THIS FRONT...HIGHS WILL ONLY BE IN THE 50S ACROSS THE EXTREME
NORTHERN CWA...WITH WIDESPREAD 70S TO THE SOUTH.
LATEST SPC CONVECTIVE OUTLOOK MAINTAINS SLIGHT CHANCES OF SEVERE
WEATHER...MAINLY THIS AFTERNOON AND TONIGHT. SIGNIFICANT CAP
SHOULD ERODE BY LATE MORNING AS MU-CAPES RISE TO AROUND 1500
J/KG...AND 0-6KM BULK SHEAR INCREASES TO AROUND 40-45 KNOTS BY
LATE AFTERNOON. MAIN LINE OF STRONG TO SEVERE STORMS EXPECTED TO
DEVELOP ACROSS MISSOURI DURING THE AFTERNOON AND TREK
EASTWARD...BUT RAP AND NAM DO SHOW SOME WEAKER CONVECTION
IMMEDIATELY ALONG OUR BOUNDARY AT TIMES AS WELL. WIND DAMAGE
SHOULD BE THE MAIN THREAT IN OUR AREA AS THE CONVECTION ORGANIZES
INTO A LINEAR MCS TO OUR WEST...BUT SOME LARGE HAIL WILL ALSO BE
POSSIBLE...ESPECIALLY IF ANYTHING FORMS AHEAD OF THE MAIN LINE.
PRECIPITABLE WATER VALUES PROGGED TO BE AROUND 1.4 TO 1.5 INCHES
THROUGH TONIGHT...WHICH IS ABOUT 2 STANDARD DEVIATIONS ABOVE
NORMAL FOR THIS TIME OF YEAR...SO WILL LIKELY SEE SOME HEAVIER
RAINS WITH THE STORMS AS WELL.
THE COLD FRONT TRAILING THE LOW SHOULD CROSS THE INDIANA BORDER
EARLY THURSDAY MORNING...TAKING MOST OF THE RAIN WITH IT. HAVE
LINGERED SOME LIKELY POPS ALONG THE BORDER FOR THE MORNING...BUT
DRY SLOT WILL BE WORKING ITS WAY ACROSS MOST OF THE AREA. HAVE NOT
COMPLETELY REMOVED THE RAIN CHANCES THOUGH...AS THE UPPER LOW
MOVES ACROSS IOWA AND POTENTIALLY BRINGS SOME SHOWERS THIS FAR
SOUTHEAST...ESPECIALLY IN THE NORTHERN CWA. TEMPERATURES NOT
EXPECTED TO DO MUCH AND WILL BE WARMEST IN THE EAST...AS IT WILL
TAKE MOST OF THE DAY FOR 850 MB TEMPS TO FALL BELOW ZERO THAT FAR
EAST.
LONG TERM...SATURDAY THROUGH TUESDAY...
UPPER LOW EXPECTED TO SLOWLY WEAKEN AS IT LIFTS INTO THE GREAT
LAKES REGION LATE THIS WEEK. BOTH THE GFS AND ECMWF MODELS TRY TO
ESTABLISH SOME SORT OF ZONAL FLOW THIS WEEKEND...WITH ANOTHER LOW
RIDING EASTWARD ALONG THE CANADIAN BORDER INTO NORTH DAKOTA BEFORE
DIGGING A TROUGH WEST OF THE ROCKIES. MAINLY DRY CONDITIONS ARE
EXPECTED THE FIRST HALF OF THE WEEKEND. BY SATURDAY NIGHT...A
SHORTWAVE WILL BE MOVING THROUGH THE PLAINS. THE TWO MODELS DO NOT
HANDLE THIS TRANSITION WELL...WITH THE ECMWF SLOWER AND STRONGER
WITH THE SECOND UPPER LOW AND THUS KEEPING US IN THE WARM SECTOR
LONGER...WHILE THE GFS DRAPES A WARM FRONT OVER CENTRAL ILLINOIS.
HOWEVER...EVENTUALLY THE TWO PHASE THE SURFACE FEATURES BETTER BY
MONDAY. WILL HAVE RAIN CHANCES MENTIONED FROM SUNDAY THROUGH
TUESDAY.
GEELHART
&&
.AVIATION...
ISSUED 1130 PM CDT TUE APR 9 2013
COLD FRONT HAS SHIFTED SOUTH TO JUST NORTH OF PIA AND BMI AND IS
STILL EXPECTED TO PUSH TO NEAR KSPI...KDEC AND KCMI BY WEDNESDAY
MORNING...BEFORE SHIFTING BACK NORTH AS ANOTHER AREA OF LOW
PRESSURE PUSHES INTO WESTERN IL BY WED EVENING. NOT VERY CONFIDENT
ON JUST WHERE THE MVFR CIGS WILL SET UP NORTH OF THE FRONTAL
BOUNDARY WITH SFC OBS TO OUR NORTH INDICATING THE NEAREST MVFR
CIG JUST NORTH OF JOLIET. BASED ON THE CURRENT TRENDS...IT STILL
APPEARS OUR NORTHERN TAF SITES WOULD HAVE THE HIGHEST PROBABILITIES
OF SEEING A PERIOD OF MVFR CIGS WITH POSSIBLY SOME TEMPO IFR CIGS
AS WELL WEDNESDAY MORNING. IF THE FRONT SHIFTS FURTHER SOUTH THAN
WHAT IS CURRENTLY EXPECTED...ALL SITES WILL SEE A PERIOD OF MVFR
CIGS INTO EARLY AFTN. FOR NOW...WILL CONTINUE TO KEEP THE LOWEST CIGS
AT KPIA AND KBMI. SHOWERS AND THUNDERSTORMS STILL SLATED TO PUSH
INTO OUR AFTER 08Z ACRS THE WEST AND THEN SPREAD INTO THE EAST BY
12Z WITH SCATTERED SHOWERS AND STORMS POSSIBLE ON AND OFF DURING THE
DAY ON WEDNESDAY. THE MAIN COLD FRONT IS NOT SLATED TO PUSH INTO OUR
AREA UNTIL AFTER THIS FORECAST PERIOD SO IT APPEARS THE THREAT FOR
RAIN AND THUNDER...ALONG WITH AT LEAST MVFR CIGS WILL INCREASE AGAIN
WEDNESDAY NIGHT. SFC WINDS WILL BE EAST TO THE NORTH OF THE FRONT
AND MORE SOUTHEAST AHEAD OF THE COLD FRONT. SPEEDS WILL RANGE FROM
10 TO 15 KTS...BUT A FEW GUSTS AROUND 20 KTS WILL BE POSSIBLE LATE
TOMORROW MORNING AND ESPECIALLY WEDNESDAY AFTN AND EVENING.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1013 AM EDT WED APR 10 2013
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 341 AM EDT WED APR 10 2013
A STRONG LOW PRESSURE SYSTEM WILL PUSH THROUGH CENTRAL INDIANA
TONIGHT AND TOMORROW...TRIGGERING STRONG TO SEVERE THUNDERSTORMS
ALONG AND AHEAD OF AN ASSOCIATED COLD FRONT. CONVECTIVE ACTIVITY
WILL TAPER OFF BY TOMORROW EVENING WITH ONLY SOME LINGERING
SHOWERS INTO FRIDAY MORNING. DRY AND COOL WEATHER WILL BE THE NORM
FOR FRIDAY AND SATURDAY IN THE WAKE OF AFOREMENTIONED COLD FRONT.
HOWEVER...ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME
LATE IN THE WEEKEND AS ANOTHER SYSTEM MOVES THROUGH THE GREAT
LAKES REGION.
&&
.NEAR TERM /REST OF TODAY/...
ISSUED AT 1011 AM EDT WED APR 10 2013
AT 10 AM RADAR MOSAIC SHOWED ALMOST NO ECHOES ACROSS THE FORECAST
AREA. WARM/STATIONARY FRONT IS JUST NORTH OF THE FORECAST AREA
BETWEEN RENSSELAER AND LAFAYETTE. TEMPERATURES WERE IN THE LOW 70S
WITH DEW POINTS IN THE LOW 60S AND WINDS OUT OF THE SOUTHWEST AROUND
25 MPH. BASED ON TRENDS AND HRRR/RAP OUTPUT DECREASED POPS FOR THE
NEXT COUPLE OF HOURS. THEN INCREASED POPS SOME FOR THE AFTERNOON
WITH RAPID UPDATE MODELS SHOWING CONVECTIVE DEVELOPMENT ACROSS THE
AREA BY LATE THIS AFTERNOON. ALTHOUGH LARGER SCALE FRONTAL FORCING
WILL STILL BE ABSENT...WATER VAPOR SATELLITE AND SURFACE ANALYSIS
INDICATE A WEAK WAVE CURRENTLY OVER EASTERN MISSOURI/WESTERN
ILLINOIS THAT SHOULD MOVE ALONG THE FRONT AND PROVIDE THE NECESSARY
FORCING THIS AFTERNOON/EVENING TO TAP INTO WHAT SHOULD BE AMPLE
INSTABILITY WITH OVER 60 DEW POINTS AND HIGH TEMPERATURES REACHING
INTO THE UPPER 70S/LOW 80S ON STRONG SOUTHWESTERLY FLOW. ALSO SEEING
SOME CLEARING ON SATELLITE TO THE SOUTHWEST...SO THINK THOSE 80S
COULD STILL BE ATTAINABLE DESPITE CURRENT CLOUD COVER.
GIVEN THE INSTABILITY AND FORCING MENTIONED ABOVE...DO SEE SOME
POTENTIAL FOR SEVERE THIS AFTERNOON INTO EVENING AND HAVE ADDED THIS
TO THE HWO. WHILE INSTABILITY WILL BE LOWER TONIGHT STILL SEE
STRONGER FORCING AND DYNAMICS PRESENT WITH FRONTAL PASSAGE LATE
TONIGHT/EARLY THURSDAY SO SEVERE WILL BE IN PLAY THEN AS WELL.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 341 AM EDT WED APR 10 2013
THE MAIN FOCUS OF THE SHORT TERM PERIOD IS SEVERE WEATHER
POTENTIAL FOR TONIGHT AND TOMORROW.
SPC CONTINUES TO KEEP ALL OF CENTRAL INDIANA UNDER A SLIGHT RISK
FOR SEVERE WEATHER THROUGH DAY 1. CURRENT THINKING IS THAT COLD
FRONT WILL START IMPACTING THE WESTERN PORTIONS OF CENTRAL INDIANA
AFTER THU 06Z TONIGHT AND KEEP PROPAGATING EAST THROUGH EARLY
TOMORROW MORNING. THIS WOULD PUT THE BULK OF THUNDERSTORMS THROUGH
THE INDY METRO SOMEWHERE IN THE THU 09-15Z TIME FRAME. FORECAST
SOUNDINGS ARE HINTING AT SBCAPES OF 1000 TO 1500 J/KG WITH AMPLE
MOISTURE AND HEAT IN PLACE. A STRONG LOW LEVEL JET OVER 60 KTS
SHOULD ACCELERATE SEVERE THUNDERSTORM DEVELOPMENT AFTER THU 06.
AN UPPER LEVEL JET WILL ACCOMPANY THE UPPER LEVEL LOW TOMORROW
AFTERNOON...BUT EXPECTING ENVIRONMENT TO BE WORKED OVER BY THAT
POINT. NONETHELESS...WILL KEEP MENTION OF ISOLATED THUNDERSTORMS
OVER THE FORECAST AREA UNTIL THAT UPPER LOW HAS EXITED THE REGION.
TEMPS...WAS ABLE TO GO WITH ALLBLEND IN WAKE OF THE SYSTEM AS
MODELS COME INTO AGREEMENT WITH THE WEATHER PATTERN. MUCH COOLER
TEMPS IN THE 40S AND 50S CAN BE EXPECTED FOR FRIDAY WITH DRY
CONDITIONS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 341 AM EDT WED APR 10 2013
SATURDAY AND SATURDAY NIGHT WILL BE DRY AS HIGH PRESSURE WILL BE
MOVING EAST ACROSS THE OHIO VALLEY. AFTER THAT THERE IS
DISAGREEMENT BETWEEN MODELS ON HOW QUICK RAIN MOVES BACK IN. THE
GFS BRINGS RAIN BACK IN SUNDAY AS A WARM FRONT DEVELOPS ACROSS OUR
REGION WITH LOW PRESSURE OVER THE CENTRAL PLAINS. THE GEMNH AND 12Z
EURO MODELS ARE ALMOST 24 HOURS SLOWER AND THEY DO NOT INDICATE SUCH
A STRONG FRONTAL SYSTEM SETTING UP ACROSS OUR REGION. WITH THE GFS
BEING A WET OUTLIER...WILL DOWN PLAY RAIN CHANCES SOME SUNDAY AND
SUNDAY NIGHT. WILL MENTION SLIGHT CHANCES ACROSS OUR NORTHWEST
SUNDAY AFTERNOON AND LOW CHANCES NORTHWEST 2/3 OF OUR REGION SUNDAY
NIGHT...BUT LOWER POPS THAN CONSALL AND ALL BLEND NUMBERS. FROM
MONDAY ON WILL GO WITH CHANCES POPS...THE GEMNH BRINGS A FRONT TO
OUR REGION AND THE 12Z EURO HAS IT JUST TO OUR NORTHWEST.
AS FAR AS TEMPERATURES ARE CONCERNED...RAISED ALL BLEND TEMPERATURES
SOME SUNDAY AS THE GFS INDICATES MUCH COOLER TEMPERATURES WITH
CLOUDS AND PRECIP...WHICH MAY SOMEWHAT SKEW ALL BLEND NUMBERS. ALSO
TWEAKED TEMPERATURES UP A LITTLE SATURDAY TO BETTER MATCH MEX AND
HPC NUMBERS. ALL BLEND TEMPERATURES SEEM REASONABLE REST OF THE
EXTENDED.
&&
.AVIATION /DISCUSSION FOR 101500Z TAF ISSUANCE/...
ISSUED AT 1010 AM EDT WED APR 10 2013
ISOLATED CONVECTION ACROSS EASTERN INDIANA ASSOCIATED WITH A SUBTLE
WAVE ALOFT. IN THE WAKE OF THIS FEATURE...HAVE SEEN POCKETS OF MVFR
STRATOCU DEVELOP AT ALL BUT KLAF. EXPECT THESE LOWER CLOUDS TO
PERSIST TO SOME DEGREE THROUGH THE REMAINDER OF THE MORNING...WITH
CURRENT VIS SATELLITE SHOWING CLOUDS SCATTERING A BIT BY MIDDAY.
THINK ANY CLEARING IS BRIEF AS ANOTHER STRONGER WAVE ALOFT MOVES OUT
OF MISSOURI AND APPROACHES THE REGION BY EARLY AFTERNOON. MOST
RECENT HRRR DATA HAS CAPTURED THE CONVECTIVE CLUSTER ASSOCIATED WITH
THIS FEATURE OVER MISSOURI NICELY...AND EXTRAPOLATION WOULD BRING
THE STORMS INTO THE WABASH VALLEY BY EARLY AFTERNOON SPREADING
ACROSS THE REST OF THE REGION THEREAFTER. HAVE ADJUSTED TIMING OF
THUNDERSTORMS WITHIN TAFS TO ALIGN TO THIS THINKING.
12Z DISCUSSION FOLLOWS.
NUMEROUS THUNDERSTORMS WILL OCCUR FROM THE LOWER GREAT LAKES TO MID
MISSISSIPPI VALLEY THROUGH THE PERIOD AS AN EAST WEST STATIONARY
FRONT WILL CONTINUE ACROSS NORTHERN INDIANA TO LOW PRESSURE MOVING
EAST INTO THE MID MISSISSIPPI VALLEY.
LATEST RAPID REFRESH MODEL INDICATES THERE MAY TWO POSSIBLE PEAK
TIMES FOR THUNDERSTORMS ACROSS CENTRAL INDIANA. SHOWERS AND
THUNDERSTORMS PRESENTLY OVER THE MID MISSISSIPPI VALLEY WILL BUILD
EAST INTO CENTRAL INDIANA BY MIDDAY. FOLLOWED BY A LULL IN
THUNDERSTORMS THE FIRST HALF TO TWO THIRDS OF TONIGHT.
THE LOW PRESSURE WILL MOVE TO NEAR KCHI BY 12Z THURSDAY WITH A COLD
FRONT PUSHING INTO WESTERN INDIANA. ANOTHER ROUND OF STRONG
THUNDERSTORMS WILL LIKELY OCCUR THEN.
OUTSIDE OF THUNDERSTORMS CEILINGS WILL GENERALLY BE 3-5 THOUSAND
FEET AND VISIBILITIES 6 MILES OR BETTER.
SOUTH TO SOUTHWEST WINDS WILL INCREASE TO 15 KNOTS WITH GUSTS TO 25
KNOTS BY LATE MORNING. WINDS TONIGHT WILL BE SOUTH TO SOUTHWEST 10
TO 12 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...CP
SHORT TERM...TDUD
LONG TERM....JH
AVIATION...JH/RYAN
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1010 AM EDT WED APR 10 2013
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
ISSUED AT 341 AM EDT WED APR 10 2013
A STRONG LOW PRESSURE SYSTEM WILL PUSH THROUGH CENTRAL INDIANA
TONIGHT AND TOMORROW...TRIGGERING STRONG TO SEVERE THUNDERSTORMS
ALONG AND AHEAD OF AN ASSOCIATED COLD FRONT. CONVECTIVE ACTIVITY
WILL TAPER OFF BY TOMORROW EVENING WITH ONLY SOME LINGERING
SHOWERS INTO FRIDAY MORNING. DRY AND COOL WEATHER WILL BE THE NORM
FOR FRIDAY AND SATURDAY IN THE WAKE OF AFOREMENTIONED COLD FRONT.
HOWEVER...ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS WILL COME
LATE IN THE WEEKEND AS ANOTHER SYSTEM MOVES THROUGH THE GREAT
LAKES REGION.
&&
.NEAR TERM /TODAY/...
ISSUED AT 341 AM EDT WED APR 10 2013
STRONG WARM AIR ADVECTION WILL CONTINUE TODAY AHEAD OF AN
APPROACHING SYSTEM. STRONG SOUTHWEST WINDS OF 10 TO 20 MPH WILL
HELP TEMPS TOP OFF IN THE LOW 80S ONCE AGAIN TODAY ACROSS MOST OF
CENTRAL INDIANA. THE ONLY EXCEPTION WILL BE OVER THE NORTHWEST
QUADRANT WHERE MORNING SHOWERS AND THUNDERSTORMS ALONG A STALLED
FRONTAL BOUNDARY WILL PROHIBIT TEMPS FROM GETTING ANY HIGHER THAN
THE MID 70S. THE NAM WAS COMING IN CONSIDERABLY WARMER THAN THE
GFS IN REGARD TO TODAY/S HIGHS...AND TRENDED EVEN A FEW MORE
DEGREES ABOVE THOSE FORECASTED HIGHS. DEWPOINTS ARE EXPECTED TO
CLIMB INTO THE MID 60S...SETTING UP A FAVORABLE ENVIRONMENT FOR
STRONG TO SEVERE THUNDERSTORM DEVELOPMENT WITH COLD FRONT TONIGHT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ISSUED AT 341 AM EDT WED APR 10 2013
THE MAIN FOCUS OF THE SHORT TERM PERIOD IS SEVERE WEATHER
POTENTIAL FOR TONIGHT AND TOMORROW.
SPC CONTINUES TO KEEP ALL OF CENTRAL INDIANA UNDER A SLIGHT RISK
FOR SEVERE WEATHER THROUGH DAY 1. CURRENT THINKING IS THAT COLD
FRONT WILL START IMPACTING THE WESTERN PORTIONS OF CENTRAL INDIANA
AFTER THU 06Z TONIGHT AND KEEP PROPAGATING EAST THROUGH EARLY
TOMORROW MORNING. THIS WOULD PUT THE BULK OF THUNDERSTORMS THROUGH
THE INDY METRO SOMEWHERE IN THE THU 09-15Z TIME FRAME. FORECAST
SOUNDINGS ARE HINTING AT SBCAPES OF 1000 TO 1500 J/KG WITH AMPLE
MOISTURE AND HEAT IN PLACE. A STRONG LOW LEVEL JET OVER 60 KTS
SHOULD ACCELERATE SEVERE THUNDERSTORM DEVELOPMENT AFTER THU 06.
AN UPPER LEVEL JET WILL ACCOMPANY THE UPPER LEVEL LOW TOMORROW
AFTERNOON...BUT EXPECTING ENVIRONMENT TO BE WORKED OVER BY THAT
POINT. NONETHELESS...WILL KEEP MENTION OF ISOLATED THUNDERSTORMS
OVER THE FORECAST AREA UNTIL THAT UPPER LOW HAS EXITED THE REGION.
TEMPS...WAS ABLE TO GO WITH ALLBLEND IN WAKE OF THE SYSTEM AS
MODELS COME INTO AGREEMENT WITH THE WEATHER PATTERN. MUCH COOLER
TEMPS IN THE 40S AND 50S CAN BE EXPECTED FOR FRIDAY WITH DRY
CONDITIONS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ISSUED AT 341 AM EDT WED APR 10 2013
SATURDAY AND SATURDAY NIGHT WILL BE DRY AS HIGH PRESSURE WILL BE
MOVING EAST ACROSS THE OHIO VALLEY. AFTER THAT THERE IS
DISAGREEMENT BETWEEN MODELS ON HOW QUICK RAIN MOVES BACK IN. THE
GFS BRINGS RAIN BACK IN SUNDAY AS A WARM FRONT DEVELOPS ACROSS OUR
REGION WITH LOW PRESSURE OVER THE CENTRAL PLAINS. THE GEMNH AND 12Z
EURO MODELS ARE ALMOST 24 HOURS SLOWER AND THEY DO NOT INDICATE SUCH
A STRONG FRONTAL SYSTEM SETTING UP ACROSS OUR REGION. WITH THE GFS
BEING A WET OUTLIER...WILL DOWN PLAY RAIN CHANCES SOME SUNDAY AND
SUNDAY NIGHT. WILL MENTION SLIGHT CHANCES ACROSS OUR NORTHWEST
SUNDAY AFTERNOON AND LOW CHANCES NORTHWEST 2/3 OF OUR REGION SUNDAY
NIGHT...BUT LOWER POPS THAN CONSALL AND ALL BLEND NUMBERS. FROM
MONDAY ON WILL GO WITH CHANCES POPS...THE GEMNH BRINGS A FRONT TO
OUR REGION AND THE 12Z EURO HAS IT JUST TO OUR NORTHWEST.
AS FAR AS TEMPERATURES ARE CONCERNED...RAISED ALL BLEND TEMPERATURES
SOME SUNDAY AS THE GFS INDICATES MUCH COOLER TEMPERATURES WITH
CLOUDS AND PRECIP...WHICH MAY SOMEWHAT SKEW ALL BLEND NUMBERS. ALSO
TWEAKED TEMPERATURES UP A LITTLE SATURDAY TO BETTER MATCH MEX AND
HPC NUMBERS. ALL BLEND TEMPERATURES SEEM REASONABLE REST OF THE
EXTENDED.
&&
.AVIATION /DISCUSSION FOR 101500Z TAF ISSUANCE/...
ISSUED AT 1010 AM EDT WED APR 10 2013
ISOLATED CONVECTION ACROSS EASTERN INDIANA ASSOCIATED WITH A SUBTLE
WAVE ALOFT. IN THE WAKE OF THIS FEATURE...HAVE SEEN POCKETS OF MVFR
STRATOCU DEVELOP AT ALL BUT KLAF. EXPECT THESE LOWER CLOUDS TO
PERSIST TO SOME DEGREE THROUGH THE REMAINDER OF THE MORNING...WITH
CURRENT VIS SATELLITE SHOWING CLOUDS SCATTERING A BIT BY MIDDAY.
THINK ANY CLEARING IS BRIEF AS ANOTHER STRONGER WAVE ALOFT MOVES OUT
OF MISSOURI AND APPROACHES THE REGION BY EARLY AFTERNOON. MOST
RECENT HRRR DATA HAS CAPTURED THE CONVECTIVE CLUSTER ASSOCIATED WITH
THIS FEATURE OVER MISSOURI NICELY...AND EXTRAPOLATION WOULD BRING
THE STORMS INTO THE WABASH VALLEY BY EARLY AFTERNOON SPREADING
ACROSS THE REST OF THE REGION THEREAFTER. HAVE ADJUSTED TIMING OF
THUNDERSTORMS WITHIN TAFS TO ALIGN TO THIS THINKING.
12Z DISCUSSION FOLLOWS.
NUMEROUS THUNDERSTORMS WILL OCCUR FROM THE LOWER GREAT LAKES TO MID
MISSISSIPPI VALLEY THROUGH THE PERIOD AS AN EAST WEST STATIONARY
FRONT WILL CONTINUE ACROSS NORTHERN INDIANA TO LOW PRESSURE MOVING
EAST INTO THE MID MISSISSIPPI VALLEY.
LATEST RAPID REFRESH MODEL INDICATES THERE MAY TWO POSSIBLE PEAK
TIMES FOR THUNDERSTORMS ACROSS CENTRAL INDIANA. SHOWERS AND
THUNDERSTORMS PRESENTLY OVER THE MID MISSISSIPPI VALLEY WILL BUILD
EAST INTO CENTRAL INDIANA BY MIDDAY. FOLLOWED BY A LULL IN
THUNDERSTORMS THE FIRST HALF TO TWO THIRDS OF TONIGHT.
THE LOW PRESSURE WILL MOVE TO NEAR KCHI BY 12Z THURSDAY WITH A COLD
FRONT PUSHING INTO WESTERN INDIANA. ANOTHER ROUND OF STRONG
THUNDERSTORMS WILL LIKELY OCCUR THEN.
OUTSIDE OF THUNDERSTORMS CEILINGS WILL GENERALLY BE 3-5 THOUSAND
FEET AND VISIBILITIES 6 MILES OR BETTER.
SOUTH TO SOUTHWEST WINDS WILL INCREASE TO 15 KNOTS WITH GUSTS TO 25
KNOTS BY LATE MORNING. WINDS TONIGHT WILL BE SOUTH TO SOUTHWEST 10
TO 12 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...TDUD
NEAR TERM...TDUD
SHORT TERM...TDUD
LONG TERM....JH
AVIATION...JH/RYAN
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
414 AM EDT WED APR 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 413 AM EDT WED APR 10 2013
ISSUES ABOUND THIS MORNING IN TERMS OF TEMPERATURES...PCPN
CHANCES...FLOODING AND SEVERE WEATHER POTENTIAL.
COLD FRONT HAS NOT MADE A LOT OF PROGRESS OVER THE PAST COUPLE OF
HOURS...PRESENTLY LYING FROM NORTH OF LAFAYETTE TO NORTHWEST OF FT
WAYNE TO SOUTH OF DEFIANCE. TEMPS RANGED FROM THE LOWER 40S ALONG
THE LAKE TO MIDDLE 60S IN SE AREAS. WIDELY SCATTERED SHOWERS HAVE
BEEN FORMING ON AND OFF ALL NIGHT BUT HAVEN`T AMOUNTED TO MUCH. 850
MB FRONT REMAINS LOCATED FROM CNTRL LWR MI INTO SOUTHERN WISCONSIN
TO IOWA AND INTO EASTERN KANSAS. LARGE AREA OF PRECIP WAS MOVING
ACROSS WISCONSIN AND NORTHERN LK MI INTO CNTRL/N LWR MI. ANOTHER
AREA OF RAIN/STORMS EXTENDED FROM N MISSOURI INTO MUCH OF SOUTHERN
IOWA. HI RES MODELS SLOWLY BRING THE MO/IA ACTIVITY ENE WITH LLJ
INCREASING IN ADVANCE OF IT WITH 50 KTS ALREADY INTO CENTRAL
ILLINOIS. 00Z SPC 4KM WRF APPEARS TO HAVE A DECENT HANDLE ON THE
SITUATION AND RAPIDLY DEVELOPS PRECIP ACROSS NW AREAS THIS
MORNING...SPREADING SE WITH TIME. HAVE TRIED TO ADD FURTHER DETAIL
TO THE GRIDS BUT FURTHER REFINEMENTS ARE LIKELY AS WE AWAIT TO SEE
HOW THE MESOSCALE FEATURES PLAY OUT. BY THIS AFTERNOON...WARM SECTOR
WILL BE LOCATED ACROSS AT LEAST THE FAR SOUTHERN/SW COUNTIES. RAP
SURGES IT BACK NORTH FOR A BRIEF PERIOD IN RESPONSE TO THE
APPROACHING WAVE. WHILE NOT AS AGGRESSIVE AS RAP HAVE TRIED TO
CAPTURE EXPECTED TRENDS WITH A COLD DAY ACROSS THE NORTH AND TEMPS
WELL INTO THE 70S SOUTH. SEVERE POTENTIAL WILL EXIST IN THE WARM
SECTOR WITH STRONGER CELLS BUT OVERALL COVERAGE OF STRONGER STORMS
MAY BE SOMEWHAT LIMITED DESPITE CAPES PUSHING 1000 J/KG AND
FAVORABLE 0-6 KM SHEAR OVER 40 KTS.
AREA OF LOW PRESSURE DRIFTS TOWARDS THE AREA TONIGHT WITH WARM FRONT
LOCATED ACROSS OUR FAR SOUTHERN COUNTIES OR INTO CENTRAL INDIANA.
ALL MODELS POINT TOWARDS WIDESPREAD RAIN WITH EMBEDDED STORMS.
SEVERAL MODELS STILL CRANK OUT WIDESPREAD 1 TO 3 INCH RAINFALL
AMOUNTS ESPECIALLY ACROSS S LWR MI/FAR N INDIANA. FOR THE TIME BEING
WILL CONTINUE FLOODING THREAT MENTION IN HWO BUT NOT ISSUE ANY FLOOD
WATCH UNTIL EFFECTS OF DAYTIME CONVECTION CAN BE ASSESSED. SEVERE
POTENTIAL WILL LIKELY SHIFT SOUTH OF THE AREA TONIGHT AS AMOUNT OF
COLD AIR NORTH OF THE WARM FRONT WILL KEEP INSTABILITY ELEVATED BUT
STILL SUFFICIENT TO WARRANT THUNDER MENTION. LARGE TEMP GRADIENT
TONIGHT EXPECTED WITH LOWS IN THE MID 30S NORTH TO THE MID 50S
SOUTH.
&&
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 413 AM EDT WED APR 10 2013
AMPLIFIED FLW PATTN TYPICAL OF SPRING TO CONT THIS PD. EWD EJECTION
OF DEEP/NEG HGT ANOMALY OUT OF THE CNTRL PLAINS AND INTO THE WRN
LAKES FAIRLY WELL AGREED UPON PER SPECTRAL CONSENSUS AND IN LIGHT OF
XPCD MID LVL DRY SLOTTING FRI WILL WHITTLE DOWN SRN EXTENT OF
MENTIONABLE POPS. OTRWS TEMPS BACK TO WELL BLO NORMALS WITHIN STG LL
CAA REGIME.
COLD TEMPS XPCD TO CONT THROUGH SAT BFR LL COLD POCKET BEGINS TO
MODIFY AHD OF NEXT STG DISTURBANCE DIGGING INTO THE NRN ROCKIES BY
SUN. DECIDED PREFERENCE TWD ECM/GEM CAMP IN HOLDING MORE INTENSE
CLOSED MID LVL CYCLONE ACRS THE NRN PLAINS OF WHICH WILL DELAY EWD
FNTL INTRUSION AND ASSOCD PCPN. THUS WILL BACK POP MENTION OFF UNTIL
SUN NIGHT WEST/MON EAST. HWVR NRN EJECTION OF THIS SYS ALG THE
US/CANADIAN BORDER DOES NOT BODE WELL FOR PRECIP ALG ORPHANED SWWD
TRAILING FNTL BNDRY LT PD AND WILL HOLD W/PRIOR GRIDDED POPS DYS6-7.
TEMPS MODERATING BACK TWD NORMAL FROM MON ONWARD.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 413 AM EDT WED APR 10 2013
MESSY MESOSCALE ENVIRONMENT AND MULTIPLE BOUNDARY
LOCATION WILL RAISE HAVOC ON TAFS THROUGH THE PERIOD.
COLD FRONT WAS WELL THROUGH KSBN AND MAKING SLOW PROGRESS TOWARDS
KFWA. MARINE LAYER HAS STRUGGLED TO MAKE IT INTO KSBN WITH NE FLOW
ADVECTING IN 4000 FT DECK AND KEEPING 200 FOOT CIGS JUST OFF TO THE
WEST FOR NOW. HAVE INCREASED CIGS THE REMAINDER OF THE NIGHT BUT
WILL NEED TO WATCH FOR ANY CHANGE IN LL FLOW THAT COULD QUICKLY
SWING THE LIFR CONDITIONS INTO THE AREA. IN THE WARM SECTOR OF THE
SYSTEM...SHOWERS HAVE BEEN DEVELOPING AND ATTEMPTING TO
GROW...GENERALLY SCT IN NATURE. CIGS/VSBYS DON`T APPEAR TO BE
MAJORLY IMPACTED OTHER THAN BRIEF EXCURSION INTO MVFR WITH HEAVIER
SHOWERS. MINOR ADJUSTMENTS TO KFWA TO HANDLE TRENDS BUT KEEP MENTION
OF THUNDER OUT FOR NOW.
BETTER CHANCES FOR STORMS WILL COME WEDS MORNING AS 850 MB FRONT TO
THE NORTH SINKS SOUTH SOMEWHAT AND ENERGY FROM CONVECTION TO THE
WEST MOVES ACROSS THE AREA. NEW 00Z 4KM SPC WRF SEEMS TO HAVE A VERY
GOOD HANDLE ON CURRENT PRECIP ACROSS MUCH OF THE US AND BASED ON ITS
TRENDS...AN UPTICK IN CONVECTION WILL LIKELY OCCUR IN 2 WINDOWS..ONE
STARTING AFTER 15Z THROUGH ABOUT 21Z WEDS THEN A BRIEF LULL BEFORE
THE SFC LOW AND MUCH DEEPER LIFT AND MSTR ARRIVE TO BRING
RAIN/STORMS WEDS NGT. HAVE MADE SOME ADJUSTMENTS TO CIGS IN LATER
PERIOD BUT AT THIS POINT KEPT REMAINDER OF THE FORECAST GOING WITH
MVFR CIGS/VSBYS SETTLING IN. HOPING BY 12Z ISSUANCE TO BE ABLE TO
PIN DOWN BETTER TIMING OF CONVECTIVE POTENTIAL AND ADD FURTHER
DETAILS. REGARDLESS...ROUGH FLYING WEATHER WILL BE ON TAP FOR THE
NEXT 24 TO 36 HOURS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 2 PM EDT THURSDAY FOR LMZ043-046.
&&
$$
SHORT TERM...FISHER
LONG TERM...T
AVIATION...FISHER
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1230 AM EDT WED APR 10 2013
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
ISSUED AT 153 PM EDT TUE APR 9 2013
PERSISTENT STALLED BOUNDARY REMAINS IN THE REGION TODAY...AND WILL
REMAIN SO THROUGH TOMORROW...WITH POTENTIAL FOR A FEW SHOWERS AND
THUNDERSTORMS. TOMORROW NIGHT INTO THURSDAY A STRONG LOW PRESSURE
SYSTEM WILL PUSH THROUGH THE AREA AND DRAG A COLD FRONT
THROUGH...BRINGING POSSIBLE STRONG TO SEVERE STORMS AND THEN A
COOL DOWN TOWARD THE END OF THE WEEK. QUIET WEATHER WILL CONTINUE
INTO THE WEEKEND AS HIGH PRESSURE BUILDS INTO THE AREA.
&&
.NEAR TERM /REST OF TONIGHT/...
ISSUED AT 955 PM EDT TUE APR 9 2013
HAVE LOWERED POPS THIS EVENING AND DELAYED THEIR SOUTHWARD
DEVELOPMENT OVERNIGHT. ONLY A FEW SPRINKLES ARE BEING REPORTED
ACROSS THE NORTHWEST FORECAST AREA AT THE MOMENT. THE FRONT TO OUR
NORTH IS SAGGING SOUTH...BUT NOT MUCH CONVECTION IS ASSOCIATED
WITH IT.
WITH NO SIGNIFICANT UPPER WAVE MOVING IN TO HELP TRIGGER
CONVECTION...FEEL THAT LIKELY POPS ARE NO LONGER WARRANTED LATER
TONIGHT. HAVE LOWERED THEM TO CHANCE CATEGORY ACROSS THE
NORTHWEST. LEFT IN THE LOW CHANCES ACROSS THE SOUTH
OVERNIGHT...BUT NOT CONFIDENT THESE AREAS WILL SEE ANYTHING.
OTHER CONCERN THEN IS TEMPERATURES. KANKAKEE IN ILLINOIS HAS FALLEN
26 DEGREES IN THE LAST TWO HOURS AS FRONT SAGS BACK SOUTH...AND
RENSSELAER HAS FALLEN NEARLY 10 DEGREES. RUC13 KEEPS THE COLD AIR
JUST NORTH OF THE FORECAST AREA TONIGHT. HAVE LOWERED TEMPERATURES
A FEW DEGREES ACROSS THE EXTREME NORTHWEST FORECAST AREA FOR
NOW...BUT IF THE FRONT SNEAKS IN...LOW TEMPERATURES WILL BE A LOT
COOLER THAN FORECAST THERE.
ELSEWHERE CLOUDS AND SOUTH WINDS WILL HELP KEEP TEMPERATURES
WARM...POSSIBLY NEAR RECORD HIGH MINIMUMS.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
ISSUED AT 153 PM EDT TUE APR 9 2013
GUIDANCE CONTINUES TO GRADUALLY SLOW STRONG LOW AND COLD
FRONT...NOW PASSING ACROSS THE AREA VERY LATE WEDNESDAY NIGHT INTO
MIDDAY THURSDAY. APPEARS THAT THIS WILL BE THE BEST TIME FOR
THUNDERSTORMS...POSSIBLY STRONG TO SEVERE. AT THE VERY LEAST...A
GOOD SOAKING RAIN IS LIKELY WITH PERIODS OF HEAVY RAIN POSSIBLE.
CONSENSUS TEMPS AGREE REMARKABLY WELL WITH LOW LEVEL
THICKNESSES...WITH A FEW MINOR TWEAKS AROUND FRONTAL PASSAGE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
ISSUED AT 213 PM EDT TUE APR 9 2013
FRIDAY NIGHT THROUGH SATURDAY NIGHT WILL BE DRY WITH HIGH PRESSURE
MOVING EAST ACROSS OUR REGION. A MODERATE SOUTHERLY FLOW WILL
DEVELOP ACROSS OUR AREA SUNDAY AS LOW PRESSURE MOVES INTO THE UPPER
MIDWEST. WITH QUITE A BIT OF UNCERTAINTY BETWEEN MODELS WILL
INDICATE SLIGHT CHANCE POPS ACROSS ALL AREAS SUNDAY NIGHT AS A WEAK
FRONTAL SYSTEM APPROACHES OUR AREA LATE. ON MONDAY WILL CONTINUE
WITH ALL BLEND POPS OF 20 PERCENT. TEMPERATURES WILL BE QUITE COOL
FRIDAY AND GRADUALLY WARM UP OVER THE WEEKEND.
&&
.AVIATION /DISCUSSION FOR 100600Z TAF ISSUANCE/...
ISSUED AT 1230 AM EDT WED APR 10 2013
WOULD NOT RULE OUT A SHOWER OR TWO AND POSSIBLY EVEN A THUNDERSTORM
OVERNIGHT AT LAF AS A RETREATING WARM FRONT HAS DROPPED SOUTH TO
JUST NORTH OF LAF. OTHERWISE...THUNDERSTORM COVERAGE SHOULD INCREASE
AFTER 15Z ESPECIALLY AT LAF AS LOW PRESSURE SLIDES EAST ACROSS
NORTHERN MISSOURI AND INTO CENTRAL ILLINOIS BY 06Z THURSDAY. COLD
FRONT WILL TRAIL SOUTH OF THE LOW...AND 35 PLUS KNOT LOW LEVEL JET
WILL AID INCREASING LOW LEVEL MOISTURE AND SHEAR. ALSO...VFR SHOULD
BECOME MVFR AT LEAST AT TIMES THROUGH THE REMAINDER OF THE TAF
PERIOD.
BUFKIT SUGGESTS SOUTH AND SOUTHWEST WINDS LESS THAN 10 KNOTS
OVERNIGHT WILL INCREASE TO NEAR 15 KNOTS WITH GUSTS TO 20 KNOTS OR
MORE AFTER 15Z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...50
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...MK/JH
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1228 PM CDT WED APR 10 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM.../TODAY /...
SURFACE LOW PRESSURE OVER NERN MO WILL BE SLOW TO MOVE NORTHEAST
TODAY AS THE NEXT ROUND OF FORCING APPROACHES THE AREA. GUSTY WINDS
OVERNIGHT DUE TO A WAVE DISTURBANCE IN THE WAKE OF THE LAST LINE OF
TSRA SHOULD SUBSIDE EARLY IN THE FORECAST PERIOD. WITH UPPER LOW
STILL APPROACHING AND THE SURFACE LOW BECOMING CAPTURED...COLD AIR
WILL BE SLOWED SOMEWHAT MOVING INTO THE CWA. WRAP AROUND WARM AIR
WILL LIKELY KEEP TEMPS NEAR TO JUST ABOVE FREEZING OVER THE
NORTHWEST WITH WBZ TEMPS VERY CLOSE TO FREEZING. THINKING IS THAT
DURING THE DAY PROBLEMS WILL BE MINIMAL. COLD AIR SHOULD MAKE
PROGRESS AFTER SUNSET. AS FOR THE REST OF THE STATE...DO NOT SEE A
LOW OF CHANGE IN THE TEMPS TODAY WITH ONLY MODEST RISES AT BEST
CENTRAL AND SOUTHEAST. MAIN AREA OF RAIN IS ADVANCING TO THE EAST
FAIRLY QUICKLY NOW AND WEAKENING WITH TIME. MOST OF THE MORNING
WILL SHOW LITTLE IN THE AMOUNT OF RAINFALL...OR ONLY LIGHT AMOUNTS.
NEXT ROUND OF FORCING MOVES ACROSS THE STATE THIS AFTERNOON AND
THERE WILL BE A PICK UP ON THE AREA AND INTENSITY. AWR/NMM HIRES
MODELS HAVE A PRETTY GOOD HANDLE ON THIS WITH THE HRRR RUNNING A BIT
FAST.
.LONG TERM.../TONIGHT THROUGH TUESDAY/...
EXTENDED PERIOD OF PRECIPITATION REMAINS ACROSS CWA THROUGH
BEGINNING OF LONG TERM. AS SURFACE LOW PULLS EAST THROUGH
MISSOURI...UPPER LEVEL LOW WILL LIFT NE...WITH ONLY FAIR MODEL
AGREEMENT ON TACK OF UPPER LEVEL LOW. NAM AND PREVIOUS GFS RUN
PULLED LOW THROUGH IOWA THROUGH THURSDAY. LATEST GFS TAKES TRACK
FURTHER NORTH...CLOSER TO ECMWF TRACK. HAVE TRENDED TOWARDS
PREVIOUS GFS TRACK WHICH WAS CONSISTENT WITH NAM AND HAD BETTER
HANDLING OF SURFACE LOW. IN ADDITION...LATEST GEM IS MORE IN LINE
WITH SLIGHTLY SOUTHERLY TRACK ACROSS IOWA. THETA-E ADVECTION
LINGERS ACROSS NORTHERN IOWA AHEAD OF UPPER LEVEL LOW...AND SLOWLY
PUSHES EAST ACROSS STATE. ANTICIPATE LINGERING CHANCES FOR
PRECIPITATION ACROSS MUCH OF THE STATE THROUGH TONIGHT. IN
ADDITION...COULD SEE PRECIPITATION ACROSS THE WEST REDEVELOP LATE
THURSDAY AS DEF ZONE WRAPS AROUND LOW TRACKING EAST. BEFORE ENTIRE
SYSTEM FINALLY PULLS NORTHEAST OF AREA BY LATE FRIDAY WITH ONLY
LINGERING LIGHT SNOW ACROSS THE NE FRIDAY.
MAIN CONCERN WILL AGAIN BE WITH PRECIPITATION TYPE ACROSS MUCH OF
THE CWA TONIGHT AND THURSDAY. SOUNDINGS AND MODELS STILL CONTINUE
TO INDICATE A STRONG WARM LAYER...ENOUGH TO MELT ICE PARTICLES
AND NEAR SURFACE COLD LAYER. THIS COULD LEAD TO CHANCES FOR
FREEZING RAIN AGAIN ACROSS THE NORTH TONIGHT. BEST CHANCES WILL BE
AROUND MASON CITY. HOWEVER...NAM AGAIN REMAINS VERY BULLISH WITH
STRENGTH OF WARM LAYER...AND GFS KEEPS WARM LAYER VERY CLOSE TO 3C
WHICH...WHICH MAY NOT FULLY MELT HYDROMETEOR. THEREFORE...DO NOT
HAVE HIGH CONFIDENCE IN ZR AND HAVE INCLUDED RAIN WITH CHANCE FOR
ZR. FURTHER WEST...NEAR SURFACE COLD LAYER MAY BE DEEP ENOUGH...UP
TO ALMOST 900MB TO REFREEZE AND LEAD TO SLEET. HAVE KEPT
SNOW/SLEET MENTION OR RAIN/SLEET MENTION ACROSS MUCH OF THE
WESTERN CWA BEFORE COLD TEMPERATURES FINALLY WORK IN BEHIND LOW
AND PRECIPITATION SWITCHES TO SNOW. WILL SEE GOOD LIFT THROUGH
DENDRITC ZONE WITH SNOWFALL...AND COULD SEE HIGH SNOWFALL RATES
FOR A TIME TONIGHT INTO EARLY THURSDAY...ESPECIALLY ACROSS THE
NORTHWEST. WILL KEEP WINTER STORM WARNING AS IS...WITH SNOWFALL
TOTALS GENERALLY BETWEEN 3-7 INCHES IN THE WARNING AREA...BUT WILL
BE VARIABLE DEPENDING ON WHEN SWITCH OVER TO SNOW OCCURS. IN
ADDITION...MAY NEED ADVISORY FOR ZR FURTHER EAST...BUT AS STATED
DO NOT HAVE HIGH CONFIDENCE IN PROLONGED ZR EVENT...THOUGH A LIGHT
GLAZE IS POSSIBLE BY EARLY THURSDAY MORNING.
TEMPERATURES WILL WARM BACK TO NEAR NORMAL FOR THE WEEKEND AS
RIDGE AND HIGH PRESSURE PUSH QUICKLY ACROSS THE AREA. BEHIND THIS
HIGH...ANOTHER LOW PRESSURE SYSTEM IS SET TO AFFECT THE AREA FOR
EARLY NEXT WEEK. HOWEVER...MODELS AGAIN DO NOT HAVE GOOD AGREEMENT
ON HANDLING OF THIS SYSTEM...WITH GFS THE OUTLIER...PULING LOW
FURTHER SOUTH. HOWEVER...ANOTHER CHANCE FOR PROLONGED
PRECIPITATION CHANCES IS LIKELY EARLY IN THE WEEK. WITH WARMER
TEMPERATURES WILL SEE RAINFALL DURING THE DAY...BUT MAY SEE
RAIN/SNOW OVERNIGHT AS TEMPERATURES COOL...ESPECIALLY ACROSS THE
NORTH. THIS SYSTEM WILL NEED TO BE WATCHED AS IT NEARS.
&&
.AVIATION...10/18Z
ISSUED AT 1228 PM CDT WED APR 10 2013
IFR/LIFR CIGS WILL PERSIST THROUGH MUCH OF THE TAF FORECAST PERIOD
WITH ANOTHER WAVE OF PRECIP MOVING ACROSS THE STATE THIS
AFTERNOON. MAY SEE SOME BRIEF MVFR TO IFR VIS THROUGH
TONIGHT...BUT OVERALL EXPECTING THE WORST VIS TO BE AT FOD WHEN
PRECIP SWITCHES TO ALL SNOW TOWARDS THURSDAY MORNING. EXPECTING
SOME IMPROVEMENT AT DSM/OTM AND POSSIBLY ALO BY THURSDAY MORNING
AS MAIN PRECIP BAND LOOKS TO SHIFT NORTHWARD. WINDS WILL SLOWLY
SHIFT FROM THE EAST TO NORTHEAST DURING THE AFTERNOON...THEN MORE
NORTH TO NORTHWEST OVERNIGHT INTO THURSDAY.
&&
.HYDROLOGY...
ISSUED AT 334 AM CDT WED APR 10 2013
OBSERVED AND FORECAST RAINFALL ARE NOT EXPECTED TO RESULT IN
WIDESPREAD SIGNIFICANT FLOOD IMPACTS ACROSS CENTRAL IOWA FOR THE
NEXT FEW DAYS. THE THREAT OF FLOODING AND FLASH FLOODING IS NOT
PRESENTLY HIGH ENOUGH TO WARRANT A FLOOD WATCH. RAINFALL OVERNIGHT
TOTALED OVER 2 INCHES IN A SMALL PART OF SOUTHEAST IA WEST AND
NORTH OF KOTM BASED ON RADAR ESTIMATES. MOST AREAS OF THE
SOUTHEAST HALF OF THE CWA APPEARS TO BE IN THE 1 TO 1.5 INCH
RANGE.
THE FLASH FLOOD THREAT IS MINIMAL OVER THE NEXT 24 HRS AS RAINFALL
HAS TENDED TO MOVE THROUGH AREAS RATHER THAN TRAINING. LOCAL
PONDING COULD BE A PROBLEM WITH THE HEAVIER THUNDERSTORMS. THIS
SHOULD BE QUITE LOCALIZED.
THE RIVER FLOOD THREAT IS GENERALLY LOW OVER THE NEXT 24-48 HRS.
BEST CHANCES FOR QPF ENSEMBLE HYDROGRAPHS SUGGEST THAT ONLY A
COUPLE RIVER FORECAST POINTS MAY APPROACH OR REACH FLOOD STAGE. A
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 7 PM CDT THIS EVENING FOR APPANOOSE-
BLACK HAWK-BREMER-BUTLER-DAVIS-DECATUR-GRUNDY-LUCAS-MAHASKA-
MONROE-POWESHIEK-RINGGOLD-TAMA-TAYLOR-WAPELLO-WAYNE.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR EMMET-KOSSUTH-
PALO ALTO-WINNEBAGO.
&&
$$
SHORT TERM...MS APR 13
LONG TERM...AWB
AVIATION...PODRAZIK
HYDROLOGY...MS APR 13
AREA FORECAST DISCUSSION
NWS DES MOINES IA
642 AM CDT WED APR 10 2013
.SHORT TERM.../TODAY /...
SURFACE LOW PRESSURE OVER NERN MO WILL BE SLOW TO MOVE NORTHEAST
TODAY AS THE NEXT ROUND OF FORCING APPROACHES THE AREA. GUSTY WINDS
OVERNIGHT DUE TO A WAVE DISTURBANCE IN THE WAKE OF THE LAST LINE OF
TSRA SHOULD SUBSIDE EARLY IN THE FORECAST PERIOD. WITH UPPER LOW
STILL APPROACHING AND THE SURFACE LOW BECOMING CAPTURED...COLD AIR
WILL BE SLOWED SOMEWHAT MOVING INTO THE CWA. WRAP AROUND WARM AIR
WILL LIKELY KEEP TEMPS NEAR TO JUST ABOVE FREEZING OVER THE
NORTHWEST WITH WBZ TEMPS VERY CLOSE TO FREEZING. THINKING IS THAT
DURING THE DAY PROBLEMS WILL BE MINIMAL. COLD AIR SHOULD MAKE
PROGRESS AFTER SUNSET. AS FOR THE REST OF THE STATE...DO NOT SEE A
LOW OF CHANGE IN THE TEMPS TODAY WITH ONLY MODEST RISES AT BEST
CENTRAL AND SOUTHEAST. MAIN AREA OF RAIN IS ADVANCING TO THE EAST
FAIRLY QUICKLY NOW AND WEAKENING WITH TIME. MOST OF THE MORNING
WILL SHOW LITTLE IN THE AMOUNT OF RAINFALL...OR ONLY LIGHT AMOUNTS.
NEXT ROUND OF FORCING MOVES ACROSS THE STATE THIS AFTERNOON AND
THERE WILL BE A PICK UP ON THE AREA AND INTENSITY. AWR/NMM HIRES
MODELS HAVE A PRETTY GOOD HANDLE ON THIS WITH THE HRRR RUNNING A BIT
FAST.
.LONG TERM.../TONIGHT THROUGH TUESDAY/...
EXTENDED PERIOD OF PRECIPITATION REMAINS ACROSS CWA THROUGH
BEGINNING OF LONG TERM. AS SURFACE LOW PULLS EAST THROUGH
MISSOURI...UPPER LEVEL LOW WILL LIFT NE...WITH ONLY FAIR MODEL
AGREEMENT ON TACK OF UPPER LEVEL LOW. NAM AND PREVIOUS GFS RUN
PULLED LOW THROUGH IOWA THROUGH THURSDAY. LATEST GFS TAKES TRACK
FURTHER NORTH...CLOSER TO ECMWF TRACK. HAVE TRENDED TOWARDS PREVIOUS
GFS TRACK WHICH WAS CONSISTENT WITH NAM AND HAD BETTER HANDLING OF
SURFACE LOW. IN ADDITION...LATEST GEM IS MORE IN LINE WITH SLIGHTLY
SOUTHERLY TRACK ACROSS IOWA. THETA-E ADVECTION LINGERS ACROSS
NORTHERN IOWA AHEAD OF UPPER LEVEL LOW...AND SLOWLY PUSHES EAST
ACROSS STATE. ANTICIPATE LINGERING CHANCES FOR PRECIPITATION ACROSS
MUCH OF THE STATE THROUGH TONIGHT. IN ADDITION...COULD SEE
PRECIPITATION ACROSS THE WEST REDEVELOP LATE THURSDAY AS DEF ZONE
WRAPS AROUND LOW TRACKING EAST. BEFORE ENTIRE SYSTEM FINALLY PULLS
NORTHEAST OF AREA BY LATE FRIDAY WITH ONLY LINGERING LIGHT SNOW
ACROSS THE NE FRIDAY.
MAIN CONCERN WILL AGAIN BE WITH PRECIPITATION TYPE ACROSS MUCH OF
THE CWA TONIGHT AND THURSDAY. SOUNDINGS AND MODELS STILL CONTINUE TO
INDICATE A STRONG WARM LAYER...ENOUGH TO MELT ICE PARTICLES AND NEAR
SURFACE COLD LAYER. THIS COULD LEAD TO CHANCES FOR FREEZING RAIN
AGAIN ACROSS THE NORTH TONIGHT. BEST CHANCES WILL BE AROUND MASON
CITY. HOWEVER...NAM AGAIN REMAINS VERY BULLISH WITH STRENGTH OF WARM
LAYER...AND GFS KEEPS WARM LAYER VERY CLOSE TO 3C WHICH...WHICH MAY
NOT FULLY MELT HYDROMETEOR. THEREFORE...DO NOT HAVE HIGH CONFIDENCE
IN ZR AND HAVE INCLUDED RAIN WITH CHANCE FOR ZR. FURTHER WEST...NEAR
SURFACE COLD LAYER MAY BE DEEP ENOUGH...UP TO ALMOST 900MB TO
REFREEZE AND LEAD TO SLEET. HAVE KEPT SNOW/SLEET MENTION OR
RAIN/SLEET MENTION ACROSS MUCH OF THE WESTERN CWA BEFORE COLD
TEMPERATURES FINALLY WORK IN BEHIND LOW AND PRECIPITATION SWITCHES
TO SNOW. WILL SEE GOOD LIFT THROUGH DENDRITC ZONE WITH
SNOWFALL...AND COULD SEE HIGH SNOWFALL RATES FOR A
TIME TONIGHT INTO EARLY THURSDAY...ESPECIALLY ACROSS THE
NORTHWEST. WILL KEEP WINTER STORM WARNING AS IS...WITH SNOWFALL
TOTALS GENERALLY BETWEEN 3-7 INCHES IN THE WARNING AREA...BUT WILL
BE VARIABLE DEPENDING ON WHEN SWITCH OVER TO SNOW OCCURS. IN
ADDITION...MAY NEED ADVISORY FOR ZR FURTHER EAST...BUT AS STATED DO
NOT HAVE HIGH CONFIDENCE IN PROLONGED ZR EVENT...THOUGH A LIGHT
GLAZE IS POSSIBLE BY EARLY THURSDAY MORNING.
TEMPERATURES WILL WARM BACK TO NEAR NORMAL FOR THE WEEKEND AS
RIDGE AND HIGH PRESSURE PUSH QUICKLY ACROSS THE AREA. BEHIND THIS
HIGH...ANOTHER LOW PRESSURE SYSTEM IS SET TO AFFECT THE AREA FOR
EARLY NEXT WEEK. HOWEVER...MODELS AGAIN DO NOT HAVE GOOD AGREEMENT
ON HANDLING OF THIS SYSTEM...WITH GFS THE OUTLIER...PULING LOW
FURTHER SOUTH. HOWEVER...ANOTHER CHANCE FOR PROLONGED
PRECIPITATION CHANCES IS LIKELY EARLY IN THE WEEK. WITH WARMER
TEMPERATURES WILL SEE RAINFALL DURING THE DAY...BUT MAY SEE
RAIN/SNOW OVERNIGHT AS TEMPERATURES COOL...ESPECIALLY ACROSS THE
NORTH. THIS SYSTEM WILL NEED TO BE WATCHED AS IT NEARS.
&&
.AVIATION...10/12Z
ISSUED AT 638 AM CDT WED APR 10 2013
LOW PRESSURE OVER NERN MO WILL MOVE LITTLE TODAY...THEN ADVANCE
INTO IL TONIGHT. INVERTED TROF EXTENDING NNWWD OUT OF THE LOW WILL
REMAIN IN PLACE OVER THE STATE TODAY. WIDESPREAD IFR CONDITIONS IN
STRATUS THROUGH THE FORECAST PERIOD. AREAS OF SHOWERS AND ISOLATED
TSRA ARE EXPECTED TODAY WITH THE THUNDER THREAT ENDING BY 00Z.
MIXED PRECIPITATION WILL SPREAD INTO THE KFOD AND MICW AREAS LATE
IN THE TAF PERIOD...BUT REMAIN ALL LIQUID ELSEWHERE.
&&
.HYDROLOGY...
ISSUED AT 334 AM CDT WED APR 10 2013
OBSERVED AND FORECAST RAINFALL ARE NOT EXPECTED TO RESULT IN
WIDESPREAD SIGNIFICANT FLOOD IMPACTS ACROSS CENTRAL IOWA FOR THE
NEXT FEW DAYS. THE THREAT OF FLOODING AND FLASH FLOODING IS NOT
PRESENTLY HIGH ENOUGH TO WARRANT A FLOOD WATCH. RAINFALL OVERNIGHT
TOTALED OVER 2 INCHES IN A SMALL PART OF SOUTHEAST IA WEST AND NORTH
OF KOTM BASED ON RADAR ESTIMATES. MOST AREAS OF THE SOUTHEAST HALF
OF THE CWA APPEARS TO BE IN THE 1 TO 1.5 INCH RANGE.
THE FLASH FLOOD THREAT IS MINIMAL OVER THE NEXT 24 HRS AS RAINFALL
HAS TENDED TO MOVE THROUGH AREAS RATHER THAN TRAINING. LOCAL
PONDING COULD BE A PROBLEM WITH THE HEAVIER THUNDERSTORMS. THIS
SHOULD BE QUITE LOCALIZED.
THE RIVER FLOOD THREAT IS GENERALLY LOW OVER THE NEXT 24-48 HRS.
BEST CHANCES FOR QPF ENSEMBLE HYDROGRAPHS SUGGEST THAT ONLY A
COUPLE RIVER FORECAST POINTS MAY APPROACH OR REACH FLOOD STAGE. A
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR APPANOOSE-BLACK HAWK-
BREMER-BUTLER-DAVIS-DECATUR-GRUNDY-LUCAS-MAHASKA-MONROE-
POWESHIEK-RINGGOLD-TAMA-TAYLOR-WAPELLO-WAYNE.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR EMMET-KOSSUTH-
PALO ALTO-WINNEBAGO.
&&
$$
SHORT TERM...MS APR 13
LONG TERM...AWB
AVIATION...MS APR 13
HYDROLOGY...MS APR 13
AREA FORECAST DISCUSSION
NWS DES MOINES IA
344 AM CDT WED APR 10 2013
.SHORT TERM.../TODAY /...
SURFACE LOW PRESSURE OVER NERN MO WILL BE SLOW TO MOVE NORTHEAST
TODAY AS THE NEXT ROUND OF FORCING APPROACHES THE AREA. GUSTY WINDS
OVERNIGHT DUE TO A WAVE DISTURBANCE IN THE WAKE OF THE LAST LINE OF
TSRA SHOULD SUBSIDE EARLY IN THE FORECAST PERIOD. WITH UPPER LOW
STILL APPROACHING AND THE SURFACE LOW BECOMING CAPTURED...COLD AIR
WILL BE SLOWED SOMEWHAT MOVING INTO THE CWA. WRAP AROUND WARM AIR
WILL LIKELY KEEP TEMPS NEAR TO JUST ABOVE FREEZING OVER THE
NORTHWEST WITH WBZ TEMPS VERY CLOSE TO FREEZING. THINKING IS THAT
DURING THE DAY PROBLEMS WILL BE MINIMAL. COLD AIR SHOULD MAKE
PROGRESS AFTER SUNSET. AS FOR THE REST OF THE STATE...DO NOT SEE A
LOW OF CHANGE IN THE TEMPS TODAY WITH ONLY MODEST RISES AT BEST
CENTRAL AND SOUTHEAST. MAIN AREA OF RAIN IS ADVANCING TO THE EAST
FAIRLY QUICKLY NOW AND WEAKENING WITH TIME. MOST OF THE MORNING
WILL SHOW LITTLE IN THE AMOUNT OF RAINFALL...OR ONLY LIGHT AMOUNTS.
NEXT ROUND OF FORCING MOVES ACROSS THE STATE THIS AFTERNOON AND
THERE WILL BE A PICK UP ON THE AREA AND INTENSITY. AWR/NMM HIRES
MODELS HAVE A PRETTY GOOD HANDLE ON THIS WITH THE HRRR RUNNING A BIT
FAST.
.LONG TERM.../TONIGHT THROUGH TUESDAY/...
EXTENDED PERIOD OF PRECIPITATION REMAINS ACROSS CWA THROUGH
BEGINNING OF LONG TERM. AS SURFACE LOW PULLS EAST THROUGH
MISSOURI...UPPER LEVEL LOW WILL LIFT NE...WITH ONLY FAIR MODEL
AGREEMENT ON TACK OF UPPER LEVEL LOW. NAM AND PREVIOUS GFS RUN
PULLED LOW THROUGH IOWA THROUGH THURSDAY. LATEST GFS TAKES TRACK
FURTHER NORTH...CLOSER TO ECMWF TRACK. HAVE TRENDED TOWARDS PREVIOUS
GFS TRACK WHICH WAS CONSISTENT WITH NAM AND HAD BETTER HANDLING OF
SURFACE LOW. IN ADDITION...LATEST GEM IS MORE IN LINE WITH SLIGHTLY
SOUTHERLY TRACK ACROSS IOWA. THETA-E ADVECTION LINGERS ACROSS
NORTHERN IOWA AHEAD OF UPPER LEVEL LOW...AND SLOWLY PUSHES EAST
ACROSS STATE. ANTICIPATE LINGERING CHANCES FOR PRECIPITATION ACROSS
MUCH OF THE STATE THROUGH TONIGHT. IN ADDITION...COULD SEE
PRECIPITATION ACROSS THE WEST REDEVELOP LATE THURSDAY AS DEF ZONE
WRAPS AROUND LOW TRACKING EAST. BEFORE ENTIRE SYSTEM FINALLY PULLS
NORTHEAST OF AREA BY LATE FRIDAY WITH ONLY LINGERING LIGHT SNOW
ACROSS THE NE FRIDAY.
MAIN CONCERN WILL AGAIN BE WITH PRECIPITATION TYPE ACROSS MUCH OF
THE CWA TONIGHT AND THURSDAY. SOUNDINGS AND MODELS STILL CONTINUE TO
INDICATE A STRONG WARM LAYER...ENOUGH TO MELT ICE PARTICLES AND NEAR
SURFACE COLD LAYER. THIS COULD LEAD TO CHANCES FOR FREEZING RAIN
AGAIN ACROSS THE NORTH TONIGHT. BEST CHANCES WILL BE AROUND MASON
CITY. HOWEVER...NAM AGAIN REMAINS VERY BULLISH WITH STRENGTH OF WARM
LAYER...AND GFS KEEPS WARM LAYER VERY CLOSE TO 3C WHICH...WHICH MAY
NOT FULLY MELT HYDROMETEOR. THEREFORE...DO NOT HAVE HIGH CONFIDENCE
IN ZR AND HAVE INCLUDED RAIN WITH CHANCE FOR ZR. FURTHER WEST...NEAR
SURFACE COLD LAYER MAY BE DEEP ENOUGH...UP TO ALMOST 900MB TO
REFREEZE AND LEAD TO SLEET. HAVE KEPT SNOW/SLEET MENTION OR
RAIN/SLEET MENTION ACROSS MUCH OF THE WESTERN CWA BEFORE COLD
TEMPERATURES FINALLY WORK IN BEHIND LOW AND PRECIPITATION SWITCHES
TO SNOW. WILL SEE GOOD LIFT THROUGH DENDRITC ZONE WITH
SNOWFALL...AND COULD SEE HIGH SNOWFALL RATES FOR A
TIME TONIGHT INTO EARLY THURSDAY...ESPECIALLY ACROSS THE
NORTHWEST. WILL KEEP WINTER STORM WARNING AS IS...WITH SNOWFALL
TOTALS GENERALLY BETWEEN 3-7 INCHES IN THE WARNING AREA...BUT WILL
BE VARIABLE DEPENDING ON WHEN SWITCH OVER TO SNOW OCCURS. IN
ADDITION...MAY NEED ADVISORY FOR ZR FURTHER EAST...BUT AS STATED DO
NOT HAVE HIGH CONFIDENCE IN PROLONGED ZR EVENT...THOUGH A LIGHT
GLAZE IS POSSIBLE BY EARLY THURSDAY MORNING.
TEMPERATURES WILL WARM BACK TO NEAR NORMAL FOR THE WEEKEND AS
RIDGE AND HIGH PRESSURE PUSH QUICKLY ACROSS THE AREA. BEHIND THIS
HIGH...ANOTHER LOW PRESSURE SYSTEM IS SET TO AFFECT THE AREA FOR
EARLY NEXT WEEK. HOWEVER...MODELS AGAIN DO NOT HAVE GOOD AGREEMENT
ON HANDLING OF THIS SYSTEM...WITH GFS THE OUTLIER...PULING LOW
FURTHER SOUTH. HOWEVER...ANOTHER CHANCE FOR PROLONGED
PRECIPITATION CHANCES IS LIKELY EARLY IN THE WEEK. WITH WARMER
TEMPERATURES WILL SEE RAINFALL DURING THE DAY...BUT MAY SEE
RAIN/SNOW OVERNIGHT AS TEMPERATURES COOL...ESPECIALLY ACROSS THE
NORTH. THIS SYSTEM WILL NEED TO BE WATCHED AS IT NEARS.
&&
.AVIATION...10/06Z
ISSUED AT 1205 AM CDT TUE APR 9 2013
LITTLE CHANGE IN CATEGORY ANTICIPATED THROUGH THE PERIOD. IFR
CONDITIONS CONTINUE OVER MUCH OF IOWA...WITH SOME MVFR AND LIFR AS
WELL..BUT IFR IS EXPECTED TO REMAIN THE PREVALENT CATEGORY WITH
PERSISTENT LOW CLOUDINESS. PLENTY OF SHOWERS AND THUNDERSTORMS
REMAIN UPSTREAM INTO KS AND WILL AFFECT IA INTO WED MORNING. ONLY
HAVE MENTION OF THUNDER INTO THE MORNING WHERE TIMING IS
ATTAINABLE. THE POTENTIAL FOR ADDITIONAL THUNDER EXISTS LATER IN
THE DAY...BUT CONFIDENCE IN LOCATIONS AND TIMING IS NOT THERE TO
MENTION. PRECIP POTENTIAL GREAT ENOUGH TO INCLUDE EXTENDED MENTION IN
THE BODY...BUT DO NOT ANTICIPATE A STEADY RAIN THROUGHOUT. EXPECT
PERSISTENT BRISK NELY WINDS WITH LITTLE CHANGE.
&&
.HYDROLOGY...
ISSUED AT 334 AM CDT WED APR 10 2013
OBSERVED AND FORECAST RAINFALL ARE NOT EXPECTED TO RESULT IN
WIDESPREAD SIGNIFICANT FLOOD IMPACTS ACROSS CENTRAL IOWA FOR THE
NEXT FEW DAYS. THE THREAT OF FLOODING AND FLASH FLOODING IS NOT
PRESENTLY HIGH ENOUGH TO WARRANT A FLOOD WATCH. RAINFALL OVERNIGHT
TOTALED OVER 2 INCHES IN A SMALL PART OF SOUTHEAST IA WEST AND NORTH
OF KOTM BASED ON RADAR ESTIMATES. MOST AREAS OF THE SOUTHEAST HALF
OF THE CWA APPEARS TO BE IN THE 1 TO 1.5 INCH RANGE.
THE FLASH FLOOD THREAT IS MINIMAL OVER THE NEXT 24 HRS AS RAINFALL
HAS TENDED TO MOVE THROUGH AREAS RATHER THAN TRAINING. LOCAL
PONDING COULD BE A PROBLEM WITH THE HEAVIER THUNDERSTORMS. THIS
SHOULD BE QUITE LOCALIZED.
THE RIVER FLOOD THREAT IS GENERALLY LOW OVER THE NEXT 24-48 HRS.
BEST CHANCES FOR QPF ENSEMBLE HYDROGRAPHS SUGGEST THAT ONLY A
COUPLE RIVER FORECAST POINTS MAY APPROACH OR REACH FLOOD STAGE. A
FEW RIVER FORECAST POINTS MAY APPROACH OR EXCEED BANKFULL.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 1 PM CDT THIS AFTERNOON FOR APPANOOSE-
BLACK HAWK-BREMER-BUTLER-DAVIS-DECATUR-GRUNDY-LUCAS-MAHASKA-
MONROE-POWESHIEK-RINGGOLD-TAMA-TAYLOR-WAPELLO-WAYNE.
WINTER STORM WARNING FROM 7 AM THIS MORNING TO 1 PM CDT THURSDAY
FOR EMMET-KOSSUTH-PALO ALTO-WINNEBAGO.
&&
$$
SHORT TERM...MS APR 13
LONG TERM...AWB
AVIATION...SMALL
HYDROLOGY...MS APR 13
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
122 PM EDT WED APR 10 2013
...Updated Aviation Discussion...
.Forecast Update...
Issued at 945 AM EDT Wed Apr 10 2013
Difficult forecast expected for today, as a lot will depend on what
happens to the cap that has kept us from getting any development the
last couple of days, despite an increase in low-level moisture. The
06Z NAM has that cap at 750-800 mb at 09Z gone by 12Z, with showers
developing already this morning. The RAP is similar, but keeps
enough of a cap through the morning. The focus for development now
however is closer to the warm front, with thunderstorms over
northern and central Indiana/Illinois. Leaning with the RUC would
indicate potential for more scattered storms across the northern
half of the forecast area later this afternoon. Still think the warm
front will grab more of the development, so will keep coverage at
isolated for now.
As for the forecast tonight, will be difficult to use most of the
usual models as they each have precip across parts of our region
already this morning. That precip will affect later timing, as the
models diurnal information will be messed up. Will probably have to
adjust the forecast more frequently today because of this
difficulty, as we see where development occurs. Already have a mid
deck of clouds forming right under that cap mentioned above, so this
may limit temperatures some. Still think areas across the east will
get near record highs, as they start off with a little more
sunshine. Best estimate is that we will see increasing development
over the far north forecast area this evening, as the focus from
that warm front to our north shifts south. Then we can expect a line
to move into western Kentucky this evening, then into our western
zones some time after midnight. With temperatures staying warm
through the evening, expect enough instability for some stronger
winds to mix down ahead of any convection that moves through.
Another concern given the slightly slower timing advertised by the
high-res models is that we will have to watch for some afternoon
redevelopment closer to the front and after the first wave of precip
moves through.
&&
.Short Term (Now through Thursday)...
Issued at 348 AM EDT Wed Apr 10 2013
...Near Record Warmth Today in East-Central Kentucky...
...Strong to Severe Thunderstorms Likely Late Tonight and Thursday...
Early morning satellite imagery and surface observations reveal
clear to partly cloudy skies across southern Indiana and central
Kentucky. Temperatures are quite mild still with readings generally
in the mid-upper 60s in many locations. For the several hours, we
expect quiet weather with temperatures slightly cooling several more
degrees before sunrise.
For today, surface warm front well to the north of our region will
stay put up that way allowing for much of the lower to middle Ohio
Valley to remain firmly entrenched in the warm sector. Generally we
expect a repeat performance of the weather seen on Tuesday with
partly to mostly sunny skies along with warm conditions. Strong
southwesterly flow within the boundary layer will lead to breezy
conditions once again this afternoon. Sustained winds of 15 to 20
MPH with gusts up to 25 MPH will be possible once again.
Temperatures will approach record highs at Frankfort (84:2011) and
at Lexington (83:2011). However, record highs at Louisville and
Bowling Green are 90 for today and that does not appear to look
attainable. The operational models continue to indicate the
possibility of some isolated convection developing this
afternoon...mainly along and west of I-65. However, model soundings
continue to show a generally capped atmosphere. Depending on solar
insolation, we may be able to break the cap in spots late this
afternoon in the far west...thus will keep a very slight chance of
PoPs out that way. Temperatures this afternoon will warm into the
79-84 degree range region wide.
For Tonight and Thursday, latest deterministic and ensemble models
continue to be in general agreement with strong upper level wave and
associated surface cyclone moving eastward out of the Plains and
into our region. Combination of strongly forced ascent due to
height falls aloft combined with favorable low-level jet/moisture
advection should result in widespread convection developing in areas
to our west late tonight. This activity will likely overspread into
southern Indiana and Kentucky late tonight...probably well after
midnight. Therefore, we will continue to run high chance PoPs late
tonight in the west and increasing PoPs steadily in the east during
the overnight hours. Depending on overall convective evolution, it
appears that overnight convection will be primarily cold pool driven
as it pushes across our area. At this point, damaging winds look to
be the primary severe weather threat late tonight in areas along and
west of I-65. Lows tonight will generally be in the mid to upper
60s.
Surface cold front should move into our western forecast area after
12Z Thursday. Initial pre-frontal convection will likely be pushing
out well ahead of it given the depth of the cold pool. With the
slower progression of the front, additional convection is likely to
fire later Thursday morning and Thursday afternoon across central
and eastern Kentucky. While strong dynamical forcing, favorable
moisture and wind shear will be present, instability is still
questionable given the likely morning convection and cloud cover
across the region. A mixed mode of strong to severe storms will be
likely with the highest threat generally along and east of I-65.
Damaging winds and large hail will be the primary severe weather
threats. However, given the ample wind shear, QLCS spinups along
the convective line will be possible. Activity should progress
eastward during the afternoon and be mostly east of our area by 00Z
Friday. Temperatures Thursday will continue to be mild ahead of the
front with lower-middle 70s expected.
.Long Term (Thursday Night through Tuesday)...
Issued at 305 AM EDT Wed Apr 10 2013
The cold front will continue to push through and east of the
forecast area Thursday night. Most of the precipitation looks to end
by 06Z Friday, though a few showers may linger longer in the east.
However, dry and cooler conditions are expected Friday as cold air
settles into the area and high pressure starts to move in.
Temperatures will reach only into the 50s on Friday. Saturday`s
highs will be similar, or possibly a couple degrees warmer as cloud
cover will be less than Friday. Temperatures on Saturday morning and
on Sunday morning still look to fall into the mid to upper 30s.
Therefore, the potential for frost headlines still remains.
By Sunday high pressure will move east of the region and winds will
shift back to southerly. Warmer, moister air will begin to advect
back into the region. Temperatures will climb back into the upper
60s to lower 70s Sunday and will be back into the upper 70s by
Tuesday. Monday through Tuesday next week a boundary will stall just
to the north of the forecast area. We will see dewpoints rise across
the area. There remains the potential for isolated to scattered
showers and thunderstorms through this time period.
&&
.Aviation (18Z TAF Issuance)...
Issued at 120 PM EDT Wed Apr 10 2013
Cap remains strong as per latest AMDAR soundings out of KSDF. Still
have some clouds just under this inversion at around 9 kft. Latest
high-res models continue to keep convection out of the forecast for
KSDF/KLEX this afternoon, but we may see some storms fire north of
those terminals by late afternoon should the cap weaken. Late
tonight, a line of storms will form and approach the KSDF/KBWG
terminals around daybreak. We may see some development just ahead of
this line after midnight, as the atmosphere will be pretty juicy for
April. Winds will continue to gust through the night as well as low
pressure deepens over the Midwest. This line should get to KLEX
later in the morning. Expect gusty winds and likely at least MVFR
conditions with the line of storms.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RJS
Short Term.......MJ
Long Term........EER
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
949 AM EDT WED APR 10 2013
.Forecast Update...
Issued at 945 AM EDT Wed Apr 10 2013
Difficult forecast expected for today, as a lot will depend on what
happens to the cap that has kept us from getting any development the
last couple of days, despite an increase in low-level moisture. The
06Z NAM has that cap at 750-800 mb at 09Z gone by 12Z, with showers
developing already this morning. The RAP is similar, but keeps
enough of a cap through the morning. The focus for development now
however is closer to the warm front, with thunderstorms over
northern and central Indiana/Illinois. Leaning with the RUC would
indicate potential for more scattered storms across the northern
half of the forecast area later this afternoon. Still think the warm
front will grab more of the development, so will keep coverage at
isolated for now.
As for the forecast tonight, will be difficult to use most of the
usual models as they each have precip across parts of our region
already this morning. That precip will affect later timing, as the
models diurnal information will be messed up. Will probably have to
adjust the forecast more frequently today because of this
difficulty, as we see where development occurs. Already have a mid
deck of clouds forming right under that cap mentioned above, so this
may limit temperatures some. Still think areas across the east will
get near record highs, as they start off with a little more
sunshine. Best estimate is that we will see increasing development
over the far north forecast area this evening, as the focus from
that warm front to our north shifts south. Then we can expect a line
to move into western Kentucky this evening, then into our western
zones some time after midnight. With temperatures staying warm
through the evening, expect enough instability for some stronger
winds to mix down ahead of any convection that moves through.
Another concern given the slightly slower timing advertised by the
high-res models is that we will have to watch for some afternoon
redevelopment closer to the front and after the first wave of precip
moves through.
&&
.Short Term (Now through Thursday)...
Issued at 348 AM EDT Wed Apr 10 2013
...Near Record Warmth Today in East-Central Kentucky...
...Strong to Severe Thunderstorms Likely Late Tonight and Thursday...
Early morning satellite imagery and surface observations reveal
clear to partly cloudy skies across southern Indiana and central
Kentucky. Temperatures are quite mild still with readings generally
in the mid-upper 60s in many locations. For the several hours, we
expect quiet weather with temperatures slightly cooling several more
degrees before sunrise.
For today, surface warm front well to the north of our region will
stay put up that way allowing for much of the lower to middle Ohio
Valley to remain firmly entrenched in the warm sector. Generally we
expect a repeat performance of the weather seen on Tuesday with
partly to mostly sunny skies along with warm conditions. Strong
southwesterly flow within the boundary layer will lead to breezy
conditions once again this afternoon. Sustained winds of 15 to 20
MPH with gusts up to 25 MPH will be possible once again.
Temperatures will approach record highs at Frankfort (84:2011) and
at Lexington (83:2011). However, record highs at Louisville and
Bowling Green are 90 for today and that does not appear to look
attainable. The operational models continue to indicate the
possibility of some isolated convection developing this
afternoon...mainly along and west of I-65. However, model soundings
continue to show a generally capped atmosphere. Depending on solar
insolation, we may be able to break the cap in spots late this
afternoon in the far west...thus will keep a very slight chance of
PoPs out that way. Temperatures this afternoon will warm into the
79-84 degree range region wide.
For Tonight and Thursday, latest deterministic and ensemble models
continue to be in general agreement with strong upper level wave and
associated surface cyclone moving eastward out of the Plains and
into our region. Combination of strongly forced ascent due to
height falls aloft combined with favorable low-level jet/moisture
advection should result in widespread convection developing in areas
to our west late tonight. This activity will likely overspread into
southern Indiana and Kentucky late tonight...probably well after
midnight. Therefore, we will continue to run high chance PoPs late
tonight in the west and increasing PoPs steadily in the east during
the overnight hours. Depending on overall convective evolution, it
appears that overnight convection will be primarily cold pool driven
as it pushes across our area. At this point, damaging winds look to
be the primary severe weather threat late tonight in areas along and
west of I-65. Lows tonight will generally be in the mid to upper
60s.
Surface cold front should move into our western forecast area after
12Z Thursday. Initial pre-frontal convection will likely be pushing
out well ahead of it given the depth of the cold pool. With the
slower progression of the front, additional convection is likely to
fire later Thursday morning and Thursday afternoon across central
and eastern Kentucky. While strong dynamical forcing, favorable
moisture and wind shear will be present, instability is still
questionable given the likely morning convection and cloud cover
across the region. A mixed mode of strong to severe storms will be
likely with the highest threat generally along and east of I-65.
Damaging winds and large hail will be the primary severe weather
threats. However, given the ample wind shear, QLCS spinups along
the convective line will be possible. Activity should progress
eastward during the afternoon and be mostly east of our area by 00Z
Friday. Temperatures Thursday will continue to be mild ahead of the
front with lower-middle 70s expected.
.Long Term (Thursday Night through Tuesday)...
Issued at 305 AM EDT Wed Apr 10 2013
The cold front will continue to push through and east of the
forecast area Thursday night. Most of the precipitation looks to end
by 06Z Friday, though a few showers may linger longer in the east.
However, dry and cooler conditions are expected Friday as cold air
settles into the area and high pressure starts to move in.
Temperatures will reach only into the 50s on Friday. Saturday`s
highs will be similar, or possibly a couple degrees warmer as cloud
cover will be less than Friday. Temperatures on Saturday morning and
on Sunday morning still look to fall into the mid to upper 30s.
Therefore, the potential for frost headlines still remains.
By Sunday high pressure will move east of the region and winds will
shift back to southerly. Warmer, moister air will begin to advect
back into the region. Temperatures will climb back into the upper
60s to lower 70s Sunday and will be back into the upper 70s by
Tuesday. Monday through Tuesday next week a boundary will stall just
to the north of the forecast area. We will see dewpoints rise across
the area. There remains the potential for isolated to scattered
showers and thunderstorms through this time period.
&&
.Aviation (12Z TAF Issuance)...
Issued at 630 AM EDT Wed Apr 10 2013
VFR conditions are expected to continue throughout much of the
upcoming TAF period as the terminals will remain entrenched in the
warm sector ahead of a strong storm system moving through the Plains
states. Light southerly winds will shift to the southwest by
mid-morning and become gusty at times. Sustained southwest winds of
15-17kts with gusts up to 22-23kts will be possible at times. We
could see some isolated convection develop west of I-65 late this
afternoon, but overall coverage still looks too sparse to include in
the TAFs at this time.
Latest data suggests that strong cold front will push toward the
Ohio Valley late tonight and into the day on Thursday. Extensive
line of convection is expected to develop west of the region this
afternoon and tonight and eventually cross into the area very late
tonight. It appears that convection will likely hold off until
after 11/06Z at KSDF and KBWG and after 11/12Z for KLEX. For now,
will add in VCTS in the KSDF and KBWG TAFs after 11/07Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RJS
Short Term.......MJ
Long Term........EER
Aviation.........MJ
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
927 PM EDT THU APR 11 2013
.UPDATE...
WITNESSING A BIFURCATION OR SPLITTING OF THE MAIN PRECIPITATION
SWATH (ALABAMA TO MICHIGAN) INTO TWO BRANCHES. THIS IS OCCURRING AT
THE FAR NORTHERN END/OVER MICHIGAN DUE TO DIFFLUENCE OF SYSTEM
RELATIVE FLOW IN THE 500-300 MB LAYER. THE ANTICYCLONIC BRANCH
(EAST..RIGHT) IS HARBORING THE PRECIPITATION NOW PUSHING INTO AREAS
SOUTH OF DETROIT. EXPECT THIS TO CONTINUE TO LIFT
NORTHWARD...WHILE TRENDING EAST OR BRUSHING THE CWA THROUGH THE
EVENING. EARLIER MODELS WERE SUGGESTING THIS WOULD ROCKET
THROUGH...ENDING BY 5Z TONIGHT HOWEVER...11.23Z RUC IS MORE
REPRESENTATIVE WITH THE CURRENT PRECIP SHIELD AND HAS END TIMING BY
7Z. IT IS THIS ANTICYCLONIC BRANCH THAT PERTAINS TO THE WARM THETA
E SURGE THAT WILL OCCUR OVER THE EASTERN HALF OF THE CWA. EXPECT A
STRAIGHT RAIN WITH TEMPERATURES THAT WILL EVEN RISE A COUPLE OF
DEGREES MOVING FORWARD. GIVEN THE RUC DEPICTION EXPECTING THIS WAA
TO LIFT NORTHWARD THROUGH THE THUMB...LARGELY HOLDING OFF ANY
PRECIPITATION TYPE CONCERNS.
THE PRECIPITATION DEVELOPING (AN HOUR OR TWO EARLIER THAN EXPECTED)
OVER WESTERN LOWER MICHIGAN IS ASSOCIATED WITH THE CYCLONIC BRANCH
(WEST...LEFT). THIS PRECIPITATION IS EXPECTED TO FILL IN AND SLOW
DOWN DURING THE DURATION OF THE EVENING WHILE LIFTING NORTHWARD
AND TRYING TO ALIGN WEST NORTHWEST TO EAST SOUTHEAST. THE CURRENT
TRAJECTORY OF THE PRECIPITATION IS DEVELOPING AS EXPECTED...TRACKING
TOWARDS THE SAGINAW VALLEY. EARLIER...MADE SOME PHONE CALLS AFTER
READING THE REPORT OF FREEZING RAIN FROM A NEIGHBORING OFFICE.
THERE WERE MULTIPLE REPORTS OF CARS SLIDING OFF ROADWAYS AND SLICK
TRAVEL CONDITIONS IN MIDLAND COUNTY. SUSPECT MUCH OF THIS GLAZING
OCCUR ED WITH THE HEAVIER PRECIPITATION RATES/EVAPORATIVE COOLING
POTENTIAL OF THE CONVECTIVE SHOWERS THAT LIFTED THROUGH THE
COUNTY BETWEEN 21-23Z. MOVING FORWARD...CYCLONIC BRANCH TRANSPORT
SHOULD LIFT INTO BAY AND MIDLAND COUNTIES BRINGING CONTINUED
CHANCES FOR LIGHT TO MODERATE PRECIPITATION THIS EVENING. A ZONAL
+90 KNOT JET OVER OKLAHOMA IS CURRENTLY DIGGING THROUGH THE BASE
OF THE TROUGH. THIS ACTION SHOULD CAUSE THE CLOSED LOW TO ROTATE
WHILE LOFTING THE POTENTIAL VORTICITY ANOMALY INTO WISCONSIN. IN
RESPONSE TO THE LOW CREEPING CLOSER...EXPECT TROWAL DYNAMICS TO
INCREASE ACROSS THE NORTHERN CWA BY 3Z PERSISTING THROUGH 9Z.
AS NOTED EARLIER...THE BULK OF WARM AIR ADVECTION WILL OCCUR OVER
THE EASTERN CWA...SO PRECIPITATION TYPE CONCERNS WILL CONTINUE.
850MB THERMAL PROGS SHOW ENOUGH WARM AIR WITHIN THE BOLSTERING TROWAL
TO SUPPORT A PREDOMINATE LIQUID TYPE. GIVEN THE CONCERNS THE
DECISION WAS MADE TO ISSUE A WINTER WEATHER ADVISORY FOR FREEZING
RAIN THROUGH 12Z FRIDAY. A SATURATED ENVIRONMENT RIGHT AT THE
FREEZING MARK BRINGS CONCERNS FOR OVERALL GLAZING AMOUNTS...BUT AN
ADDITIONAL .1 TO .2 INCHES SEEMS REASONABLE. EASTERLY SURFACE
WINDS IN THE SAGINAW VALLEY HAVE BEEN NOTEWORTHY AND
CONCERNING...WITH 20 TO 30 KNOTS OF FLOW. SPORADIC POWER OUTAGES
WILL BE POSSIBLE. PRECIPITATION TYPE MAY TRY TO TRANSITION TO
LIGHT SNOW LATE...BUT GIVEN PERSISTENT TROWAL IN PLACE SUSPECT
THIS WILL BE DIFFICULT TO OCCUR BEFORE THE BACK EDGE OF THE
PRECIPITATION LIFTS NORTHWARD. WILL CONTINUE TO MONITOR AND UPDATE
THE FORECAST AS NEEDED.
&&
.AVIATION...ISSUED 740 PM EDT THU APR 11 2013
//DISCUSSION...
MUCH OF THE INHERITED TAF FORECAST REMAINS ON TARGET. THE NEXT
SURGE OF FORCING IS ON THE DOORSTEP AND WILL TRACK THROUGH
SOUTHEASTERN MICHIGAN DURING THE NEXT FEW HOURS. THIS MOISTURE IS
EXPECTED TO DUMP CEILING HEIGHTS BACK INTO THE LIFR CATEGORY FOR
MANY AREAS. WARM AIR ADVECTION OCCURRING WITH THE NORTHWARD SURGE
OF THE OCCLUSION WILL KEEP PRECIPITATION TYPE AS A STRAIGHT RAIN
THROUGHOUT MUCH OF THE NIGHT SOUTH OF SAGINAW. FOR KMBS...A MIX
OF PRECIPITATION TYPES WILL BE POSSIBLE LATER THIS EVENING AND
CONTINUING THROUGHOUT MUCH OF THE NIGHT. WILL MONITOR TRENDS AND
AMEND THE FORECAST AS WARRANTED.
FOR DTW... THE NEXT SURGE IN MOISTURE WILL IMPACT THE TERMINAL TO
START THE PERIOD WITH A DURATION OF A FEW HOURS. THE BULK OF THIS
FIRST PRECIPITATION SURGE WILL BRUSH THE AREA TO THE SOUTHEAST.
THERE WILL THEN BE ONE FINAL ROUND THAT IS TIMED TO GO THROUGH
8-12Z TONIGHT. THIS INCREASED MOISTURE WILL MAINTAIN IFR/LIFR
CEILING AND VISIBILITY UNTIL MID TO LATE FRIDAY MORNING.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE ON CEILING BELOW 5000 FT THROUGH THE TAF PERIOD.
&&
.PREV DISCUSSION...ISSUED 358 PM EDT THU APR 11 2013
SHORT TERM... THE REMAINDER OF TODAY THROUGH TONIGHT
THE FLOOD WATCH WILL REMAIN IN EFFECT THROUGH TONIGHT AFTER SOME
BRIEF CONSIDERATION OF DROPPING FOR THE TRI CITIES. DECIDED TO HOLD
ON THERE AS WELL GIVEN MODEL TRENDS THAT LOOK REASONABLE BRINGING
THE WESTERN FLANK OF THE NEXT MOISTURE SURGE THAT FAR NORTH AND WEST
INTO THE REGION. THE PATTERN WILL INCREASE STEADILY DURING THE REST
OF THE AFTERNOON THROUGH TONIGHT AS MOISTURE TRANSPORT, RESPONSIBLE
FOR THE OHIO VALLEY ACTIVITY, WORKS NORTHWARD THROUGH LOWER
MICHIGAN. THIS IS JUST A CLASSIC CASE OF MERIDIONAL UPPER JET
SUPPORT FOR A WELL ORGANIZED AGEOSTROPHIC CIRCULATION ALONG THE COLD
FRONT. STRONG GULF MOISTURE TRANSPORT THROUGH THE LOWER HALF OF THE
ATMOSPHERE WILL ENSURE THE RESULTING PATTERN OF SHOWERS IS INGESTED
INTO THE DEEP DIFFLUENT FLOW ALOFT OVER THE GREAT LAKES DURING THE
EVENING. EXPECT THE OCCLUSION PROCESS TO MATURE DURING THE OVERNIGHT
WHICH WILL CARRY THE TROWAL AXIS AS FAR NORTH AS THE TRI CITIES
AFTER MIDNIGHT AND THE TRAILING SURFACE TROUGH THAT FAR NORTH BY
SUNRISE FRIDAY. MODEL SOLUTIONS IN THIS REGARD LOOK GOOD AND SUPPORT
MAINTAINING THUS SUPPORT MAINTAINING THE FLOOD WATCH HEADLINE FOR
ALL AREAS AT LEAST UNTIL OBSERVATIONS CAN HELP REFINE THE WESTERN
EDGE OF THE RAIN SHIELD.
WHILE SHOWERS AND A RUMBLE OF THUNDER WILL BE THE MODE OF
PRECIPITATION FOR ALL AREAS TONIGHT, SURFACE TEMPERATURE TRENDS WILL
OTHERWISE BE MONITORED FOR PRECIPITATION TYPE CONSIDERATIONS IN THE
TRI CITIES AND NORTHERN THUMB. AS IT STANDS NOW, SURFACE TEMPERATURE
IS EXPECTED TO BE MODULATED UPWARD IN THAT AREA BY THE APPROACH OF
THE SURFACE TROUGH/OCCLUSION DURING THE EVENING AND THEN SOLIDLY
SUPPORTED ABOVE FREEZING OVERNIGHT. THERE IS A CHANCE OF WINTRY MIX
MENTIONED IN THE FORECAST MAINLY NORTH OF M-46 AS A BUFFER UP
AGAINST THE HIGHER POTENTIAL TAKING SHAPE IN NORTHERN LOWER
MICHIGAN.
LONG TERM...FRIDAY THROUGH WEDNESDAY
STRONG RIGHT ENTRANCE JET SUPPORT WILL RAPIDLY WANE DURING THE
MORNING HOURS AS THE LARGE UPPER LOW OVER THE CENTRAL CONUS LIFTS TO
THE NORTH AND JET FORCING IS SHUNTED WELL NORTH OF THE AREA. THE
ASSOCIATED INTENSITY DECLINE OF MOIST ISENTROPIC ASCENT AND
NORTHWARD ROTATION OF H85-H7 DEFORMATION LAYER WILL SPELL QUICKLY
DIMINISHING PRECIP CHANCES TO START THE PERIOD, AT LEAST AS FAR AS
ORGANIZED PRECIP. STILL TAPERED POPS DOWN S LOWLY, HOWEVER, GIVEN
THE PRESENCE OF THE ELONGATED SURFACE TROUGH INDICATED ON THE 12Z
NAM. DIURNAL HEATING ALONG WITH THE EXTRA BOOST OF LOW-LEVEL
CONVERGENCE IN THE PRESENCE OF LIGHT COLD ADVECTION & A MOIST
BOUNDARY LAYER WILL BE STRONGLY SUPPORTIVE FOR SOME REDEVELOPMENT OF
SHOWERS AS THE AXIS LIFTS NORTH THROUGH THROUGH EARLY AFTERNOON.
HOWEVER, EVEN AS ANY LINGERING DIURNAL ACTIVITY WANES LATE IN THE
DAY, ONGOING COLD ADVECTION THROUGH FRIDAY NIGHT SHOULD BE
SUFFICIENT TO MAINTAIN WELL-MIXED THERMAL PROFILES AND QUITE
POSSIBLY ANOTHER ROUND OF SURFACE-BASED SHOWER ACTIVITY,
PARTICULARLY AS A LOW AMPLITUDE PV ANOMALY ROTATES ACROSS THE STATE
DURING THE FIRST HALF OF THE NIGHT. CYCLONIC FLOW ALOFT WILL FOSTER
ANOTHER SHORTWAVE ACROSS THE STATE DURING THE DAY ON SATURDAY. THE
GENERAL MODEL CONSENSUS DEPICTS THE WAVE EVOKING WESTERLY WINDS AT
THE SURFACE AND REINFORCING THE EXISTING COLD AIRMASS AS H85 TEMPS
FALL TO AROUND -10C BY LATE IN THE DAY. CONVERGENT WESTERLY LOW
WITHIN THE BOUNDARY LAYER AND MODERATE COLD ADVECTION COMBINED WITH
MID APRIL SUN SHOULD BE QUITE FAVORABLE FOR A DIURNALLY ENHANCED
LAKE EFFECT SCENARIO. COLD THERMAL PROFILES APPEAR SUPPORTIVE FOR
SNOW WITHIN MOST SHOWERS. HIGHS WILL STRUGGLE OUT OF THE 30S DURING
PEAK HEATING.
MARINE...
STRONG NORTHEAST WIND WILL PERSIST TONIGHT OVER ALL MARINE AREAS AS
A LOW PRESSURE SYSTEM LIFTS INTO THE OHIO VALLEY AND EVENTUALLY INTO
CENTRAL LOWER MICHIGAN TONIGHT INTO FRIDAY. GALES REMAIN LIKELY
ACROSS THE NORTHERN HALF OF LAKE HURON AS THIS PROCESS COMMENCES AND
A GALE WARNING REMAINS IN EFFECT. THE PERSISTENT AND INCREASING
NORTHEAST FLOW WILL CAUSE WAVE HEIGHTS TO BUILD OVER SAGINAW BAY AND
THE LAKE HURON NEARSHORE WATERS OFF THE THUMB AND WILL RESULT IN AN
EXTENDED PERIOD OF ROUGH WATER THERE. IMPROVING CONDITIONS WITH
DIMINISHING WINDS AND WAVES WILL OCCUR FRIDAY INTO FRIDAY NIGHT AS
THE SYSTEM EXITS EASTWARD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...FLOOD WATCH...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060-
MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-
MIZ083...UNTIL 8 AM FRIDAY.
WINTER WEATHER ADVISORY...MIZ047-MIZ048...UNTIL 8 AM FRIDAY.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...UNTIL 10 AM FRIDAY.
GALE WARNING...SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT
AUSTIN TO HARBOR BEACH...UNTIL 4 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...UNTIL 10 AM FRIDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...
SMALL CRAFT ADVISORY...UNTIL 10 PM THURSDAY.
&&
$$
UPDATE.......CB
AVIATION.....CB
SHORT TERM...BT
LONG TERM....JVC
MARINE.......BT
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
405 PM EDT WED APR 10 2013
.SHORT TERM...THIS EVENING AND TONIGHT
A COMPLICATED FORECAST FOR THE TONIGHT PERIOD. WILL PARTITION THE
DISCUSSION TO STRESS THE SALIENT POINTS.
THE CURRENT ROUND OF THUNDERSTORMS NOW EXITING THE FAR SOUTHEASTERN
PORTIONS OF THE CWA IS A CONTINUATION/LAST EXTENSION OF RIGHT
ENTRANCE REGION FORCING THAT HAS SINCE SLID EASTWARD ACROSS MUCH OF
ONTARIO. THIS WILL BE OUT THE DOOR IN THE NEXT HOUR. SUBSIDENCE IN
THE WAKE OF THE DYNAMICS IN COMBINATION WITH THE SHORTWAVE RIDGE
SLOWLY EXPANDING EASTWARD WILL BRING A LULL IN PRECIPITATION ACTIVITY
THROUGHOUT MUCH OF THE EVENING. THERE IS STILL A LOW TO MID CHANCE
FOR A SHOWER OR THUNDERSTORM...GIVEN THE ELEVATED FRONTAL BOUNDARY
IN PLACE OVERHEAD.
LARGE WAVELENGTH CLOSED MIDLEVEL LOW STRUCTURE OVER THE CENTRAL
UNITED STATES IS AT THIS TIME FAIRLY STATIC. THERE HAS BEEN/WILL BE
VERY LITTLE MOVEMENT OF THE FEATURE IN THE NEXT 12 TO 18 HOURS WHICH
KEEPS LOWER MICHIGAN SITUATED IN THE DOWNWIND EXHAUST PORTION OF
STRONG MOISTURE TRANSPORT/WARM AIR ADVECTION REGIME.
MODEL DATA SUGGESTS THAT CONVECTION WILL REFIRE OVER PORTIONS OF
NORTHERN MISSOURI THIS EVENING WHICH WILL BE SITUATED ON A THETA E
TRIPLE POINT STRUCTURE. THIS TRIPLE POINT/SURFACE LOW PRESSURE
CENTER WILL THEN BE FORCED UP THE RIDGE INTO THE CHICAGOLAND AREA BY
12Z THURSDAY. A COMPLEX OF PRECIPITATION/SHOWERS/THUNDERSTORMS WILL
LIFT NORTHWARD IN ADVANCE OF THE TRIPLE POINT...CRESTING THE RIDGE
AND BEGINNING TO SLIDE DOWN THE FORWARD FACE OF THE SHORTWAVE RIDGE
(WESTERN LOWER MICHIGAN)AFTER 6Z TONIGHT. LATEST THINKING IS THE
MAIN SLUG OF MOISTURE WILL BEGIN TO STRING OUT ALONG THE FRONTAL
BOUNDARY ACROSS THE NORTHWESTERN QUARTER OF THE CWA AFTER 8Z. THE
REMAINING PORTION OF THE REMNANT THUNDERSTORM COMPLEX/GLACIATED
PRECIPITATION IS THEN EXPECTED TO COLLAPSE AGAINST THE RIDGE THROUGH
SOUTHEASTERN MICHIGAN AFTER 11Z THUR.
PRIOR TO 8Z AND THE MAIN PRECIPITATION SURGE...900-800MB FRONTOGENESIS
WILL BE STRONG ENOUGH TO ALLOW FOR ADDITIONAL SHOWER AND
THUNDERSTORM DEVELOPMENT DIRECTLY OVER THE FRONTAL BOUNDARY AS IT
BEGINS MIGRATING BACK NORTHWARD ACROSS SOUTHERN LOWER MICHIGAN. THE
LATEST RUC SOLUTIONS ARE ONTO THIS GENERAL IDEA...ALTHOUGH LIKELY A
LITTLE BULLISH ON QPF AMOUNTS. AGAIN...WITH THE SHORTWAVE RIDGING
BUILDING IN OVERHEAD...FORCING WILL LARGELY BE AGAINST PRECIPITATION
GENERATION. A NORTHWARD MOVEMENT OF FRONTAL BOUNDARY SHOULD KEEP ANY
00-06Z QPF AMOUNTS IN CHECK...UP TO A QUARTER INCH OR SO.
THE VERY BIG QUESTION THAT SURFACED TODAY IS ON THE POTENTIAL FOR
FREEZING RAIN ACROSS THE FAR NORTHERN THUMB AND TRI CITIES. THE
PRIMARY FACTOR COMES DOWN TO THE SURFACE TEMPERATURES. IT APPEARS TO
BE A TENUOUS SETUP...PER USUAL...WHERE 1 TO 2 DEGREES AROUND THE
FREEZING MARK WILL MAKE A HUGE DIFFERENCE. OVERALL...MODEL
THERMODYNAMIC PROFILES IN THE LOWEST 3KFT AGL ARE VERY SUPPORTIVE
FOR FREEZING RAIN WHICH IS ACTUALLY A STOUT SLAB. STEPPING BACK AND
LOOKING AT THE BIG PICTURE...THERE ARE BOTH POSITIVES AND NEGATIVES.
THE BIG POSITIVE IS THAT WE WILL RESIDE ON PRECEDING RIDGE FACE
WHICH SHOULD VERIFY MORE COMPACT WITH THERMAL GRADIENT AND COLDER
ACROSS THE NORTHERN CWA. THE NEGATIVES INCLUDE RELATIVE WARM FLOW
2-3C OFF OF LAKE HURON AND SAGINAW BAY...A SATURATED AIRMASS...AND A
WET GROUND. THIS IS NOT A CLASSIC WET BULB COOLING TYPE EVENT WHERE
THE DRY AIR IS ENTRENCHED BEFORE PRECIP...RATHER WE WILL NEED SOME
PERSISTENT DRY AIR ADVECTION FROM NORTHEAST IN ADDITION TO NOCTURNAL
COOLING. WITH THAT STATED...THE MODELED THERMODYNAMIC PROFILE DOES
EXHIBIT A POTENTIAL FOR SOME SIGNIFICANT AMOUNTS OF FREEZING RAIN.
GIVEN THE INFLUENCE OF THE WARMER WATERS AND THE WARMER START TO THE
EVENT...WILL FORECAST ELEVATED ICING OF UP TO .2 INCH FOR INLAND
LOCATIONS. WILL ALSO LIKELY WITNESS A FAVORING TO HIGHER TERRAIN
AREAS OF FAR WESTERN MIDLAND/SAGINAW/NORTHERN BAY AND THE RIDGES OF
TUSCOLA/HURON AND SANILAC. A FREEZING RAIN ADVISORY WILL BE ISSUED
FOR THESE COUNTIES...FROM 8Z TONIGHT THROUGH 16Z TOMORROW MORNING.
GIVEN THIS PATTERN WILL NOT BREAK UNTIL THURSDAY NIGHT...THE
INHERITED FLOOD WATCH WILL BE ALLOWED TO CONTINUE.
&&
.LONG TERM...THURSDAY THROUGH WEDNESDAY
WIDESPREAD RAINFALL WILL CONTINUE AT TIMES THURSDAY INTO THURSDAY
NIGHT AS MAIN UPPER LOW EJECTS FROM THE PLAINS INTO THE WESTERN AND
NORTHERN GREAT LAKES. INITIAL FORCING WILL OCCUR ALONG ELEVATED WARM
FRONT WITH OCCLUDING COLD FRONT THEN SWEEPING INTO THE AREA LATE
THURSDAY INTO THURSDAY NIGHT.
LOW LEVEL TEMPERATURES WILL HOVER NEAR FREEZING OVER THE NORTHERN
CWA DURING THE MORNING...WITH A CONTINUED CHANCE OF FREEZING RAIN IN
LOCATIONS AWAY FROM LAKE HURON. BY NOON...TEMPERATURES WILL EDGE
INTO THE MID/UPPER 30S...ENDING ANY POTENTIAL OF RAIN FREEZING ON
SURFACES.
GIVEN THE WIDESPREAD DYNAMIC LIFT AND STRONG FORCING THAT WILL OCCUR
WITH THIS SYSTEM...WEAK/MODEST INSTABILITY WITH H85 LIFTED INDICES
IN THE -1/-3C RANGE WILL BE SUFFICIENT FOR THUNDERSTORMS DURING THE
DAY AND POSSIBLY INTO THURSDAY EVENING. ANY STORMS THAT DO DEVELOP
WILL FURTHER ENHANCE HEAVY RAINFALL POTENTIAL AND LOCALIZED
FLOODING.
ONCE THE MAIN UPPER TROUGH AXIS PIVOTS THROUGH THE REGION OVERNIGHT
THURSDAY NIGHT INTO FRIDAY...THE OVERALL PATTERN QUIETS DOWN TO SOME
EXTENT FOR A FEW DAYS AS COLDER AIR DUMPS INTO THE AREA WITHIN THE
NORTHWEST FLOW IN THE WAKE OF THIS STORM SYSTEM. A LIGHT CHANCE OF
RAIN/SNOW SHOWERS WILL PERSIST WITHIN THIS UNSETTLE CYCLONIC
FLOW...BUT WIDESPREAD HEAVIER PRECIPITATION IS NOT EXPECTED. THIS
WILL BEGIN TO CHANGE LATE THIS WEEKEND INTO NEXT WEEK AS THE UPPER
TROUGH OVER THE WESTERN CONUS RELOADS WITH A STEADY STREAM OF JET
ENERGY OFF OF THE PACIFIC AND A NUMBER OF SHORTWAVES EJECT INTO THE
AREA...BRINGING PERIODIC RAIN CHANCES LATE IN THE FORECAST PERIOD.
THE COOLER TEMPERATURES INTO THE WEEKEND...DAYTIME HIGHS OF 30S/40S
AND NIGHTTIME LOWS 20S/30...WILL MODERATE AS THE UPPER HEIGHTS RISE
WITHIN BUILDING UPPER RIDGE CENTERED OVER THE EASTERN CONUS. SO...BY
NEXT WEEK...50S/60S WILL BE MORE COMMON ACROSS THE REGION.
&&
.MARINE...
NORTHEAST WINDS WILL GRADUALLY INCREASE THROUGH THURSDAY AS A LOW
PRESSURE SYSTEM APPROACHES FROM THE PLAINS. SPEEDS WILL BE STRONGEST
OVER LAKE HURON...NORTH OF A FRONTAL BOUNDARY...REMAINING BELOW 20
KNOTS THIS EVENING THEN INCREASING FURTHER TONIGHT AND THURSDAY.
PERSISTENT AND INCREASING NORTHEAST FLOW WILL CAUSE WAVE HEIGHTS TO
BUILD OVER SAGINAW BAY AND THE LAKE HURON NEARSHORE WATERS OFF
THUMB...RESULTING IN AN EXTENDED PERIOD OF SMALL CRAFT CONDITIONS. A
BRIEF PERIOD OF GALES MAY EMERGE ACROSS CENTRAL LAKE HURON THURSDAY
EVENING...BUT MARGINAL CONDITIONS AND LIMITED DURATION WILL PRECLUDE
A WATCH HEADLINE AT THIS TIME. IMPROVING CONDITIONS WILL DIMINISHING
WINDS AND WAVES ON FRIDAY.
&&
.AVIATION...ISSUED 207 PM EDT WED APR 10 2013
//DISCUSSION...
THE WEATHER PATTERN WILL REMAIN IN A HOLDING PATTERN DURING THE
TAF PERIOD WITH A DEEP AMPLITUDE TROUGH REMAINING STATIONARY OVER
THE CENTRAL UNITED STATES. THE CURRENT BATCH OF SHOWERS AND
THUNDERSTORMS WILL SLIDE EAST THROUGH THE REGION DURING THE NEXT
COUPLE OF HOURS...WHICH SHOULD THEN LEAD INTO A RELATIVELY QUIET
PRECIPITATION FREE PERIOD THROUGH MUCH OF THE EVENING.
HOWEVER...GIVEN THE ELEVATED PORTION OF THE FRONTAL BOUNDARY AND
AMOUNT OF MOISTURE IN PLACE TO THE SOUTH OF THE FRONT...SCATTERED
SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AT JUST ABOUT ANY TIME.
THE NEXT MAIN SLUG OF MOISTURE AND PRECIPITATION WILL ARRIVE TONIGHT
AFTER 06Z FROM THE SOUTHWEST. THE WIDESPREAD PRECIPITATION IS
EXPECTED TO PUSH INTO THE FAR NORTHWESTERN CWA BEFORE SLIDING
EASTWARD TOMORROW. THERE IS ALOT OF QUESTION WITH REGARDS TO
FREEZING RAIN POTENTIAL ACROSS THE NORTH (MAINLY TRI CITIES).
THIS REMAINS A VERY TENUOUS THERMODYNAMIC SETUP WHERE SURFACE
TEMPERATURE DIFFERENCES OF 1 TO 2 DEGREES WILL MATTER. FOR
NOW...WILL INCLUDE A TEMPO GROUP AT THE END OF THE PERIOD.
OTHERWISE...SATURATED AIRMASS SUPPORTS A CONTINUED MENTION OF IFR
CEILINGS AND VISIBILITIES THROUGHOUT THE NIGHT.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE IN CEILINGS BELOW 5000 FT THROUGH THE TAF PERIOD.
* LOW CONFIDENCE IN TIMING OF THUNDERSTORMS.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...FLOOD WATCH...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060-
MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-
MIZ083...UNTIL 8 AM FRIDAY.
FREEZING RAIN ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-
MIZ055...FROM 4 AM THURSDAY TO NOON THURSDAY.
LAKE HURON...
SMALL CRAFT ADVISORY...SAGINAW BAY AND THE NEARSHORE WATERS FROM
PORT AUSTIN TO HARBOR BEACH...UNTIL 4 PM FRIDAY.
FREEZING RAIN ADVISORY...NEARSHORE WATERS FROM PORT AUSTIN TO
HARBOR BEACH...FROM 4 AM THURSDAY TO NOON THURSDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...UNTIL 10 AM FRIDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...CB
LONG TERM....DG
MARINE.......CB
AVIATION.....CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
129 PM EDT WED APR 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 552 AM EDT WED APR 10 2013
MAIN CONCERN FOR THE NEAR TERM PART OF THE FORECAST IS THE
SNOW MOVING THROUGH FAR SOUTHERN MENOMINEE COUNTY FROM A
SHORTWAVE AND CONVECTION MOVING THROUGH WISCONSIN. THIS AREA OF
PRECIPITATION HAS BEEN QUICKLY MOVING EAST AND INITIALLY STARTED
OUT AS RA/FZRA IN MENOMINEE. BUT AROUND 730Z IT QUICKLY SWITCHED
OVER TO SNOW...AS SEEN ON WEBCAMS...KMNM DROPPING TO 1.25MI AND
A REPORT FROM MENOMINEE COUNTY DISPATCH. IT APPEARED TO BE COMING
DOWN FAIRLY HARD...BUT HAS STARTED TO WEAKEN AS THE HEAVIER AND
MORE CONVECTIVE NATURE PRECIPITATION TO THE SOUTHEAST MOVES OVER
LAKE MICHIGAN. WITH THE SWITCH TO ALL SNOW...HAVE MADE SOME
ADJUSTMENTS TO PREVIOUS MENTION OF FREEZING RAIN AND BELIEVE IT WILL
MAINLY BE SNOW OR SOME ISOLATED SLEET IN ANY STRONGER BANDS. THE
THERMAL PROFILE IS FAIRLY TRICKY AND THERE COULD STILL BE A BRIEF
PERIOD OF FREEZING RAIN BEFORE ENDING AS THE RAP SHOWS THE ICE
CRYSTALS EXITING THE CLOUD TOWARDS DAYBREAK AND THE WARM NOSE
TOWARDS 1C. EXPECT TOTAL SNOW AMOUNTS IN THE CITY OF MENOMINEE IN
THE 2-3 INCH RANGE BEFORE THE SNOW COMES TO AN END AN HOUR OR TWO
AFTER DAYBREAK. WILL LIKELY FRESHEN UP A PREVIOUSLY ISSUED SPS TO
PROVIDE BETTER TIMING/AMOUNTS.
AFTER THAT PRECIPITATION OVER THE FAR SOUTH CENTRAL SHIFTS EAST THIS
MORNING...A DRY DAY IS EXPECTED ACROSS THE CWA. THIS IS LARGELY DUE
TO 850-700MB DRY AIR SEEN ON THE 00Z KINL SOUNDING ASSOCIATED WITH
THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE SUPERIOR. EVEN WITH THIS
DRY AIR...WOULD EXPECT MUCH OF THE DAY TO BE CLOUDY OR A HEAVILY
FILTERED SUNSHINE FROM MID-HIGH CLOUDS STREAMING OVER THE AREA FROM
THE UPPER LOW ENTERING THE SOUTHERN PLAINS. DID TRY TO THIN THE
CLOUDS SOMEWHAT OVER THE NORTHERN HALF OF THE CWA AND MORE TOWARDS A
PARTLY-MOSTLY CLOUDY SKIES AS THEY WILL BE FARTHER AWAY FROM THE
MOISTURE STREAMING NORTHEAST. GETTING A HANDLE ON THESE HIGH CLOUDS
ON THE NORTH SIDE OF DECAYING CONVECTION IS ALWAYS TRICKY AND IT
COULD HAVE AN INFLUENCE ON THE HIGHS TODAY...ESPECIALLY IF THERE
ARE BREAKS IN THE CLOUDS OR THEY ARE LESS THICK THAN EXPECTED.
SINCE NORTHEAST FLOW WILL KEEP COOLER AIR ALOFT FLOWING OVER THE
AREA...STILL EXPECT TEMPS TO BE BELOW NORMAL AND IN THE 30S FOR
MOST LOCATIONS. DID TREND TEMPS UP A TOUCH BASED OFF A GENERAL
CONSENSUS OF SLIGHTLY WARMER TEMPS AND MAYBE MORE OF A FILTERED
SUNSHINE. IF THE CLOUDS AREN/T AS THICK AS EXPECTED...DAY SHIFT WILL
NEED TO BUMP TEMPS UP A COUPLE DEGREES.
AREA WILL BE BETWEEN SYSTEMS THIS EVENING...AS A WEAK UPPER RIDGE
SLIDES OVER AHEAD OF THE UPPER TROUGH IN THE CENTRAL PLAINS. WITH
THE DRY MID LEVEL AIR WILL STILL BE IN PLACE HAVE TRENDED TOWARDS A
DRIER FORECAST THAT MOST OF THE HIGHER RESOLUTION MODELS ARE
SHOWING. DRY AIR WILL BEGIN TO GIVE WAY TOWARDS THE WISCONSIN BORDER
LATE TONIGHT...AS THE UPPER LOW BEGINS TO LIFT NORTHEAST TOWARD THE
GREAT LAKES AND 850-700 WARM AIR ADVECTION AND MOISTURE INCREASE.
BUT...THINK THERE WILL BE ENOUGH DRY AIR TO DELAY THE START OF THE
PRECIPITATION TO BE A LITTLE LATER THAN THE 00Z GFS/ECMWF ARE
INDICATING AND MORE INTO THURSDAY. FINALLY...THERE ARE SOME HINTS AT
NORTHEAST FAVORED UPSLOPE FLOW PRECIP ON THE HIGHER RESOLUTION
MODELS. BUT WITH THE MOISTURE VERY SHALLOW AND THE LOW CLOUDS
ALREADY CUTTING OUT EARLY THIS MORNING AT KSAW...WILL GO WITH DRY
CONDITIONS OVER THE NORTH CENTRAL AND KEWEENAW TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 552 AM EDT WED APR 10 2013
ATTENTION TURNS TO DEVELOPING STORM SYSTEM OVER THE CENTRAL
PLAINS/MID MS VALLEY AND HOW IT WILL IMPACT OUR FCST AREA FOR THU
INTO SATURDAY IT TRACKS THROUGH THE GREAT LAKES REGION. STILL PLENTY
OF MODEL UNCERTAINTY WITH THIS SYSTEM AS NEW 00Z ECMWF NOW TRENDING
TOWARD FASTER GFS SOLN. 00Z UKMET AND CANADIAN SOLNS LOOK LIKE MORE
OF A COMPROMISE BETWEEN SLOWER NAM AND FASTER GFS/ECMWF SOLNS.
SHORTWAVE RIDING FROM THE GULF COAST INTO THE OHIO VALLEY LATE
THURSDAY INTO THURSDAY NIGHT COULD ALSO THROW A WRENCH INTO THE SNOW
AMOUNTS FOR THIS FCST BY POSSIBLY ROBBING MOISTURE FROM CLOSED LOW
AND MAIN SHORTWAVE EXPECTED TO TRACK THROUGH THE UPPER GREAT LAKES.
FIRST INCLINATION IS TO SIDE WITH THE SLOWER SOLNS AS SHORTWAVE RDGG
AND ASSOC DRIER AIRMASS WILL INITIALLY BE IN PLACE OVER THE GREAT
LAKES. SLOWER MODEL SOLNS WOULD BRING PCPN (MAINLY IN THE FORM OF
SNOW) INTO SCNTRL UPR MI WED NIGHT AND THEN SLOWLY SPREAD SNOW NORTH
AND EAST MAINLY THU AFTERNOON INTO THU EVENING. WILL ALSO CONTINUE
TO MENTION POSSIBLE SLEET OVER SCNTRL PORTIONS THU INTO THU EVENING
AS NAM SNDGS SUGGEST A SHALLOW ABV FREEZING LYR ALOFT.
SNOW SHOULD BEGIN TO PICK UP LATE THU AFTERNOON AND ESPECIALLY INTO
THU NIGHT AS DPVA INCREASES AHEAD OF CLOSED LOW/MAIN SHORTWAVE
LIFTING NORTH INTO AREA. ASSOC DEEP LAYER Q-VECT CONV...STRONG
290-295K ISENTROPIC ASCENT AND 800 MB FGEN FORCING LIFTS INTO THE
AREA SHOULD ALSO SUPPORT MODERATE TO HEAVY SNOW. SNOW GROWTH AT
ONSET OF PCPN THU INTO THU EVENING WILL NOT BE AS FAVORABLE AS DGZ
WILL BE AOA 15 KFT AND BEST MODEL OMEGA WILL GENERALLY BE BLO THIS
LEVEL SO EXPECT SLR INITIALLY TO BE CLOSER TO 10/1. LATE THU NIGHT
INTO FRIDAY HOWEVER SNOW GROWTH SHOULD BECOME BETTER AS COLDER WRAPS
BACK INTO STORM SYSTEM AND PUSHES DGZ BLO 15 KFT AND INTO SOME OF
THE BETTER UPWARD LIFT (MODEL OMEGA) ASSOC WITH THE SYSTEM. BASED ON
QPF AMOUNTS RANGING FROM NEAR .2 INCH OVER THE NW CWA TO OVER .4
INCH OVER THE SE...WOULD EXPECT SNOW AMOUNTS THU NIGHT IN THE 3-6
INCH RANGE...WITH HIGHEST AMOUNTS OVER THE CNTRL PORTION OF THE CWA.
ANOTHER 2-6 INCHES WOULD BE POSSIBLE ON FRIDAY WITH THE GREATEST
AMOUNTS OVER THE HIGHER TERRAIN OF WRN MQT AND BARAGA COUNTIES WHERE
LAKE ENHANCEMENT AND UPSLOPE NE FLOW WILL BOOST SNOW TOTALS.
GIVEN CONSIDERABLE MODEL UNCERTAINTY ESPECIALLY WITH TIMING OF PCPN
AND ALSO POSSIBLE MOISTURE IMPACT OF SECONDARY SHORTWAVE RIDING
THROUGH THE OHIO VALLEY HAVE DECIDED AGAINST ISSUING A WATCH AT THIS
TIME. PRELIMINARY STORM TOTAL SNOWFALL WOULD PROBABLY ONLY SUPPORT A
WATCH FOR ONLY MQT-BARAGA COUNTIES ANYWAY...WHERE I HAVE TOTAL SNOW
ACCUMULATION...POSSIBLY EXCEEDING 10 INCHES OVER HIGHER TERRAIN
AREAS WEST OF MQT. INSTEAD WILL ISSUE AN SPS AT THIS TIME SO I CAN
INCLUDE THE ENTIRE CWA UNDER ONE STATEMENT AND STILL CONVEY MORE
UNCERTAINTY WITH TIMING OF STORM AND SNOW AMOUNTS.
BY LATE FRI NIGHT INTO SAT...EXPECT LAKE ENHANCED SNOW TO GENERALLY
TAPER OFF AS MODELS SHOW CLOSED LOW LIFTING NE OF LAKE SUPERIOR AND
FORCING WEAKENING OVER THE AREA. LINGERING MOISTURE AND CYCLONIC
N-NW FLOW WILL STILL SUPPORT SCT SNOW SHOWERS FOR NCNTRL AND NE
PORTIONS OF THE CWA INTO SAT MORNING. SHORTWAVE RIDGE BUILDING IN
FROM THE WEST AND ASSOC SUBSIDENCE SHOULD ALLOW FOR DRY CONDITIONS
AND PARTIAL CLEARING LATE SAT AFTERNOON INTO SAT NIGHT.
ECMWF AND CANADIAN MODELS STILL ON BOARD SHOWING NEXT SHORTWAVE
EMERGING OUT THE NRN PLAINS AND BRINGING A SURGE OF WARM ADVECTION
PCPN INTO THE AREA FOR MAINLY SUN AFTERNOON INTO SUNDAY NIGHT. 00Z
GFS HAS NOW ABANDONED THIS IDEA AFTER SHOWING IT IN PREV RUNS. FOR
NOW WILL TREAT GFS SOLN AS AN OUTLIER AND MAINTAIN GOING FCST OF
HIGH CHC TO LIKELY POPS FOR RAIN/SNOW MIX SUN INTO SUN NIGHT. MIXED
PCPN WILL TAPER OFF TO ISOLD/SCT SHOWERS OR JUST END ON MONDAY AS
BEST ISENTROPIC LIFT SHIFTS SE OF THE AREA. HUDSON BAY HIGH PRESSURE
NOSING IN OVER THE UPPER GREAT LAKES WILL PROVIDE DRIER BUT
CONTINUED UNSEASONABLY COOL CONDITIONS FOR UPPER MICHIGAN MON NIGHT
INTO TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 129 PM EDT WED APR 10 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AND THE MAIN CONCERN
FOR THE TAFS ARE THE SLIGHTLY GUSTY EAST-NORTHEAST WINDS TODAY AND
CONTINUING THROUGH TONIGHT. KEPT A MENTION OF SCATTERED LOW CLOUDS
AFTER MIDNIGHT TONIGHT...SINCE MODELS ARE HINTING AT SOME LOWER
LEVEL MOISTURE ARRIVING. MAIN WEATHER CONCERN IS AFTER THE TAF
PERIOD...AS A LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES BY
THURSDAY NIGHT. THIS WILL LEAD TO DETERIORATING CONDITIONS THURSDAY
INTO THURSDAY NIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EDT WED APR 10 2013
A LOW PRESSURE SYSTEM SLOWLY MOVING OUT OF THE CENTRAL PLAINS WILL
COMBINE WITH A HIGH PRESSURE IN CENTRAL CANADA TO LEAD TO A STRONG
PRESSURE GRADIENT OVER LAKE SUPERIOR FOR THE NEXT COUPLE OF DAYS.
THIS PRESSURE GRADIENT WILL LEAD TO INCREASING EAST-NORTHEASTERLY
WINDS TODAY AND TONIGHT...WITH WINDS IN THE 20-30KT RANGE TONIGHT.
EXPECT GALES TO 35KTS ON LATE TONIGHT INTO FRIDAY OVER
WESTERN LAKE SUPERIOR AND HAVE CONVERTED THE GALE WATCH TO A
WARNING FOR THAT TIME FRAME. ALSO ADDED A GALE WATCH FOR THE
REST OF THE LAKE FOR LATE THURSDAY NIGHT INTO FRIDAY AS THE
LOW TRACKS BY. SOME FREEZING SPRAY IS ALSO EXPECTED DURING THIS TIME
DUE TO THE COLDER TEMPERATURES OVER LAKE SUEPRIOR. AS THE LOW MOVES
INTO SOUTHERN QUEBEC ON FRIDAY AND FRIDAY NIGHT...EXPECT THE WINDS
TO SHIFT TO A MORE NORTHERLY DIRECTION AND THEY SHOULD DIMINISH TO
BELOW 30KTS BY THE EVENING. A WEAK HIGH PRESSURE RIDGE ON SATURDAY
WILL LEAD TO CONTINUED WEAKENING OF THE WINDS BEFORE INCREASING OUT
OF THE SOUTHEAST ON SUNDAY AHEAD OF ANOTHER LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY AFTERNOON FOR
LSZ264>267.
GALE WARNING FROM 2 AM EDT /1 AM CDT/ THURSDAY TO 2 PM EDT /1 PM
CDT/ FRIDAY FOR LSZ162-263.
LAKE MICHIGAN...
GALE WARNING FROM 5 AM THURSDAY TO 6 AM EDT FRIDAY FOR LMZ221-
248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...TITUS
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
742 AM EDT WED APR 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 552 AM EDT WED APR 10 2013
MAIN CONCERN FOR THE NEAR TERM PART OF THE FORECAST IS THE
SNOW MOVING THROUGH FAR SOUTHERN MENOMINEE COUNTY FROM A
SHORTWAVE AND CONVECTION MOVING THROUGH WISCONSIN. THIS AREA OF
PRECIPITATION HAS BEEN QUICKLY MOVING EAST AND INITIALLY STARTED
OUT AS RA/FZRA IN MENOMINEE. BUT AROUND 730Z IT QUICKLY SWITCHED
OVER TO SNOW...AS SEEN ON WEBCAMS...KMNM DROPPING TO 1.25MI AND
A REPORT FROM MENOMINEE COUNTY DISPATCH. IT APPEARED TO BE COMING
DOWN FAIRLY HARD...BUT HAS STARTED TO WEAKEN AS THE HEAVIER AND
MORE CONVECTIVE NATURE PRECIPITATION TO THE SOUTHEAST MOVES OVER
LAKE MICHIGAN. WITH THE SWITCH TO ALL SNOW...HAVE MADE SOME
ADJUSTMENTS TO PREVIOUS MENTION OF FREEZING RAIN AND BELIEVE IT WILL
MAINLY BE SNOW OR SOME ISOLATED SLEET IN ANY STRONGER BANDS. THE
THERMAL PROFILE IS FAIRLY TRICKY AND THERE COULD STILL BE A BRIEF
PERIOD OF FREEZING RAIN BEFORE ENDING AS THE RAP SHOWS THE ICE
CRYSTALS EXITING THE CLOUD TOWARDS DAYBREAK AND THE WARM NOSE
TOWARDS 1C. EXPECT TOTAL SNOW AMOUNTS IN THE CITY OF MENOMINEE IN
THE 2-3 INCH RANGE BEFORE THE SNOW COMES TO AN END AN HOUR OR TWO
AFTER DAYBREAK. WILL LIKELY FRESHEN UP A PREVIOUSLY ISSUED SPS TO
PROVIDE BETTER TIMING/AMOUNTS.
AFTER THAT PRECIPITATION OVER THE FAR SOUTH CENTRAL SHIFTS EAST THIS
MORNING...A DRY DAY IS EXPECTED ACROSS THE CWA. THIS IS LARGELY DUE
TO 850-700MB DRY AIR SEEN ON THE 00Z KINL SOUNDING ASSOCIATED WITH
THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE SUPERIOR. EVEN WITH THIS
DRY AIR...WOULD EXPECT MUCH OF THE DAY TO BE CLOUDY OR A HEAVILY
FILTERED SUNSHINE FROM MID-HIGH CLOUDS STREAMING OVER THE AREA FROM
THE UPPER LOW ENTERING THE SOUTHERN PLAINS. DID TRY TO THIN THE
CLOUDS SOMEWHAT OVER THE NORTHERN HALF OF THE CWA AND MORE TOWARDS A
PARTLY-MOSTLY CLOUDY SKIES AS THEY WILL BE FARTHER AWAY FROM THE
MOISTURE STREAMING NORTHEAST. GETTING A HANDLE ON THESE HIGH CLOUDS
ON THE NORTH SIDE OF DECAYING CONVECTION IS ALWAYS TRICKY AND IT
COULD HAVE AN INFLUENCE ON THE HIGHS TODAY...ESPECIALLY IF THERE
ARE BREAKS IN THE CLOUDS OR THEY ARE LESS THICK THAN EXPECTED.
SINCE NORTHEAST FLOW WILL KEEP COOLER AIR ALOFT FLOWING OVER THE
AREA...STILL EXPECT TEMPS TO BE BELOW NORMAL AND IN THE 30S FOR
MOST LOCATIONS. DID TREND TEMPS UP A TOUCH BASED OFF A GENERAL
CONSENSUS OF SLIGHTLY WARMER TEMPS AND MAYBE MORE OF A FILTERED
SUNSHINE. IF THE CLOUDS AREN/T AS THICK AS EXPECTED...DAY SHIFT WILL
NEED TO BUMP TEMPS UP A COUPLE DEGREES.
AREA WILL BE BETWEEN SYSTEMS THIS EVENING...AS A WEAK UPPER RIDGE
SLIDES OVER AHEAD OF THE UPPER TROUGH IN THE CENTRAL PLAINS. WITH
THE DRY MID LEVEL AIR WILL STILL BE IN PLACE HAVE TRENDED TOWARDS A
DRIER FORECAST THAT MOST OF THE HIGHER RESOLUTION MODELS ARE
SHOWING. DRY AIR WILL BEGIN TO GIVE WAY TOWARDS THE WISCONSIN BORDER
LATE TONIGHT...AS THE UPPER LOW BEGINS TO LIFT NORTHEAST TOWARD THE
GREAT LAKES AND 850-700 WARM AIR ADVECTION AND MOISTURE INCREASE.
BUT...THINK THERE WILL BE ENOUGH DRY AIR TO DELAY THE START OF THE
PRECIPITATION TO BE A LITTLE LATER THAN THE 00Z GFS/ECMWF ARE
INDICATING AND MORE INTO THURSDAY. FINALLY...THERE ARE SOME HINTS AT
NORTHEAST FAVORED UPSLOPE FLOW PRECIP ON THE HIGHER RESOLUTION
MODELS. BUT WITH THE MOISTURE VERY SHALLOW AND THE LOW CLOUDS
ALREADY CUTTING OUT EARLY THIS MORNING AT KSAW...WILL GO WITH DRY
CONDITIONS OVER THE NORTH CENTRAL AND KEWEENAW TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 552 AM EDT WED APR 10 2013
ATTENTION TURNS TO DEVELOPING STORM SYSTEM OVER THE CENTRAL
PLAINS/MID MS VALLEY AND HOW IT WILL IMPACT OUR FCST AREA FOR THU
INTO SATURDAY IT TRACKS THROUGH THE GREAT LAKES REGION. STILL PLENTY
OF MODEL UNCERTAINTY WITH THIS SYSTEM AS NEW 00Z ECMWF NOW TRENDING
TOWARD FASTER GFS SOLN. 00Z UKMET AND CANADIAN SOLNS LOOK LIKE MORE
OF A COMPROMISE BETWEEN SLOWER NAM AND FASTER GFS/ECMWF SOLNS.
SHORTWAVE RIDING FROM THE GULF COAST INTO THE OHIO VALLEY LATE
THURSDAY INTO THURSDAY NIGHT COULD ALSO THROW A WRENCH INTO THE SNOW
AMOUNTS FOR THIS FCST BY POSSIBLY ROBBING MOISTURE FROM CLOSED LOW
AND MAIN SHORTWAVE EXPECTED TO TRACK THROUGH THE UPPER GREAT LAKES.
FIRST INCLINATION IS TO SIDE WITH THE SLOWER SOLNS AS SHORTWAVE RDGG
AND ASSOC DRIER AIRMASS WILL INITIALLY BE IN PLACE OVER THE GREAT
LAKES. SLOWER MODEL SOLNS WOULD BRING PCPN (MAINLY IN THE FORM OF
SNOW) INTO SCNTRL UPR MI WED NIGHT AND THEN SLOWLY SPREAD SNOW NORTH
AND EAST MAINLY THU AFTERNOON INTO THU EVENING. WILL ALSO CONTINUE
TO MENTION POSSIBLE SLEET OVER SCNTRL PORTIONS THU INTO THU EVENING
AS NAM SNDGS SUGGEST A SHALLOW ABV FREEZING LYR ALOFT.
SNOW SHOULD BEGIN TO PICK UP LATE THU AFTERNOON AND ESPECIALLY INTO
THU NIGHT AS DPVA INCREASES AHEAD OF CLOSED LOW/MAIN SHORTWAVE
LIFTING NORTH INTO AREA. ASSOC DEEP LAYER Q-VECT CONV...STRONG
290-295K ISENTROPIC ASCENT AND 800 MB FGEN FORCING LIFTS INTO THE
AREA SHOULD ALSO SUPPORT MODERATE TO HEAVY SNOW. SNOW GROWTH AT
ONSET OF PCPN THU INTO THU EVENING WILL NOT BE AS FAVORABLE AS DGZ
WILL BE AOA 15 KFT AND BEST MODEL OMEGA WILL GENERALLY BE BLO THIS
LEVEL SO EXPECT SLR INITIALLY TO BE CLOSER TO 10/1. LATE THU NIGHT
INTO FRIDAY HOWEVER SNOW GROWTH SHOULD BECOME BETTER AS COLDER WRAPS
BACK INTO STORM SYSTEM AND PUSHES DGZ BLO 15 KFT AND INTO SOME OF
THE BETTER UPWARD LIFT (MODEL OMEGA) ASSOC WITH THE SYSTEM. BASED ON
QPF AMOUNTS RANGING FROM NEAR .2 INCH OVER THE NW CWA TO OVER .4
INCH OVER THE SE...WOULD EXPECT SNOW AMOUNTS THU NIGHT IN THE 3-6
INCH RANGE...WITH HIGHEST AMOUNTS OVER THE CNTRL PORTION OF THE CWA.
ANOTHER 2-6 INCHES WOULD BE POSSIBLE ON FRIDAY WITH THE GREATEST
AMOUNTS OVER THE HIGHER TERRAIN OF WRN MQT AND BARAGA COUNTIES WHERE
LAKE ENHANCEMENT AND UPSLOPE NE FLOW WILL BOOST SNOW TOTALS.
GIVEN CONSIDERABLE MODEL UNCERTAINTY ESPECIALLY WITH TIMING OF PCPN
AND ALSO POSSIBLE MOISTURE IMPACT OF SECONDARY SHORTWAVE RIDING
THROUGH THE OHIO VALLEY HAVE DECIDED AGAINST ISSUING A WATCH AT THIS
TIME. PRELIMINARY STORM TOTAL SNOWFALL WOULD PROBABLY ONLY SUPPORT A
WATCH FOR ONLY MQT-BARAGA COUNTIES ANYWAY...WHERE I HAVE TOTAL SNOW
ACCUMULATION...POSSIBLY EXCEEDING 10 INCHES OVER HIGHER TERRAIN
AREAS WEST OF MQT. INSTEAD WILL ISSUE AN SPS AT THIS TIME SO I CAN
INCLUDE THE ENTIRE CWA UNDER ONE STATEMENT AND STILL CONVEY MORE
UNCERTAINTY WITH TIMING OF STORM AND SNOW AMOUNTS.
BY LATE FRI NIGHT INTO SAT...EXPECT LAKE ENHANCED SNOW TO GENERALLY
TAPER OFF AS MODELS SHOW CLOSED LOW LIFTING NE OF LAKE SUPERIOR AND
FORCING WEAKENING OVER THE AREA. LINGERING MOISTURE AND CYCLONIC
N-NW FLOW WILL STILL SUPPORT SCT SNOW SHOWERS FOR NCNTRL AND NE
PORTIONS OF THE CWA INTO SAT MORNING. SHORTWAVE RIDGE BUILDING IN
FROM THE WEST AND ASSOC SUBSIDENCE SHOULD ALLOW FOR DRY CONDITIONS
AND PARTIAL CLEARING LATE SAT AFTERNOON INTO SAT NIGHT.
ECMWF AND CANADIAN MODELS STILL ON BOARD SHOWING NEXT SHORTWAVE
EMERGING OUT THE NRN PLAINS AND BRINGING A SURGE OF WARM ADVECTION
PCPN INTO THE AREA FOR MAINLY SUN AFTERNOON INTO SUNDAY NIGHT. 00Z
GFS HAS NOW ABANDONED THIS IDEA AFTER SHOWING IT IN PREV RUNS. FOR
NOW WILL TREAT GFS SOLN AS AN OUTLIER AND MAINTAIN GOING FCST OF
HIGH CHC TO LIKELY POPS FOR RAIN/SNOW MIX SUN INTO SUN NIGHT. MIXED
PCPN WILL TAPER OFF TO ISOLD/SCT SHOWERS OR JUST END ON MONDAY AS
BEST ISENTROPIC LIFT SHIFTS SE OF THE AREA. HUDSON BAY HIGH PRESSURE
NOSING IN OVER THE UPPER GREAT LAKES WILL PROVIDE DRIER BUT
CONTINUED UNSEASONABLY COOL CONDITIONS FOR UPPER MICHIGAN MON NIGHT
INTO TUE.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 742 AM EDT WED APR 10 2013
VFR CONDITIONS ARE EXPECTED THROUGH THE PERIOD AND THE MAIN CONCERN
FOR THE TAFS ARE THE SLIGHTLY GUSTY EAST-NORTHEAST WINDS DEVELOPING
TODAY AND CONTINUING THROUGH TONIGHT. ADDED A MENTION OF SCATTERED
LOW CLOUDS AFTER MIDNIGHT TONIGHT...SINCE MODELS ARE HINTING AT SOME
LOWER LEVEL MOISTURE ARRIVING. MAIN WEATHER CONCERN IS AFTER THE TAF
PERIOD...AS A LOW PRESSURE SYSTEM MOVES INTO THE GREAT LAKES BY
THURSDAY NIGHT. THIS WILL LEAD TO DETERIORATING CONDITIONS THURSDAY
INTO THURSDAY NIGHT.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EDT WED APR 10 2013
A LOW PRESSURE SYSTEM SLOWLY MOVING OUT OF THE CENTRAL PLAINS WILL
COMBINE WITH A HIGH PRESSURE IN CENTRAL CANADA TO LEAD TO A STRONG
PRESSURE GRADIENT OVER LAKE SUPERIOR FOR THE NEXT COUPLE OF DAYS.
THIS PRESSURE GRADIENT WILL LEAD TO INCREASING EAST-NORTHEASTERLY
WINDS TODAY AND TONIGHT...WITH WINDS IN THE 20-30KT RANGE TONIGHT.
EXPECT GALES TO 35KTS ON LATE TONIGHT INTO FRIDAY OVER
WESTERN LAKE SUPERIOR AND HAVE CONVERTED THE GALE WATCH TO A
WARNING FOR THAT TIME FRAME. ALSO ADDED A GALE WATCH FOR THE
REST OF THE LAKE FOR LATE THURSDAY NIGHT INTO FRIDAY AS THE
LOW TRACKS BY. SOME FREEZING SPRAY IS ALSO EXPECTED DURING THIS TIME
DUE TO THE COLDER TEMPERATURES OVER LAKE SUEPRIOR. AS THE LOW MOVES
INTO SOUTHERN QUEBEC ON FRIDAY AND FRIDAY NIGHT...EXPECT THE WINDS
TO SHIFT TO A MORE NORTHERLY DIRECTION AND THEY SHOULD DIMINISH TO
BELOW 30KTS BY THE EVENING. A WEAK HIGH PRESSURE RIDGE ON SATURDAY
WILL LEAD TO CONTINUED WEAKENING OF THE WINDS BEFORE INCREASING OUT
OF THE SOUTHEAST ON SUNDAY AHEAD OF ANOTHER LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY AFTERNOON FOR
LSZ264>267.
GALE WARNING FROM 2 AM EDT /1 AM CDT/ THURSDAY TO 2 PM EDT /1 PM
CDT/ FRIDAY FOR LSZ162-263.
LAKE MICHIGAN...
GALE WARNING FROM 5 AM THURSDAY TO 6 AM EDT FRIDAY FOR LMZ221-
248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
554 AM EDT WED APR 10 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 552 AM EDT WED APR 10 2013
MAIN CONCERN FOR THE NEAR TERM PART OF THE FORECAST IS THE
SNOW MOVING THROUGH FAR SOUTHERN MENOMINEE COUNTY FROM A
SHORTWAVE AND CONVECTION MOVING THROUGH WISCONSIN. THIS AREA OF
PRECIPITATION HAS BEEN QUICKLY MOVING EAST AND INITIALLY STARTED
OUT AS RA/FZRA IN MENOMINEE. BUT AROUND 730Z IT QUICKLY SWITCHED
OVER TO SNOW...AS SEEN ON WEBCAMS...KMNM DROPPING TO 1.25MI AND
A REPORT FROM MENOMINEE COUNTY DISPATCH. IT APPEARED TO BE COMING
DOWN FAIRLY HARD...BUT HAS STARTED TO WEAKEN AS THE HEAVIER AND
MORE CONVECTIVE NATURE PRECIPITATION TO THE SOUTHEAST MOVES OVER
LAKE MICHIGAN. WITH THE SWITCH TO ALL SNOW...HAVE MADE SOME
ADJUSTMENTS TO PREVIOUS MENTION OF FREEZING RAIN AND BELIEVE IT WILL
MAINLY BE SNOW OR SOME ISOLATED SLEET IN ANY STRONGER BANDS. THE
THERMAL PROFILE IS FAIRLY TRICKY AND THERE COULD STILL BE A BRIEF
PERIOD OF FREEZING RAIN BEFORE ENDING AS THE RAP SHOWS THE ICE
CRYSTALS EXITING THE CLOUD TOWARDS DAYBREAK AND THE WARM NOSE
TOWARDS 1C. EXPECT TOTAL SNOW AMOUNTS IN THE CITY OF MENOMINEE IN
THE 2-3 INCH RANGE BEFORE THE SNOW COMES TO AN END AN HOUR OR TWO
AFTER DAYBREAK. WILL LIKELY FRESHEN UP A PREVIOUSLY ISSUED SPS TO
PROVIDE BETTER TIMING/AMOUNTS.
AFTER THAT PRECIPITATION OVER THE FAR SOUTH CENTRAL SHIFTS EAST THIS
MORNING...A DRY DAY IS EXPECTED ACROSS THE CWA. THIS IS LARGELY DUE
TO 850-700MB DRY AIR SEEN ON THE 00Z KINL SOUNDING ASSOCIATED WITH
THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE SUPERIOR. EVEN WITH THIS
DRY AIR...WOULD EXPECT MUCH OF THE DAY TO BE CLOUDY OR A HEAVILY
FILTERED SUNSHINE FROM MID-HIGH CLOUDS STREAMING OVER THE AREA FROM
THE UPPER LOW ENTERING THE SOUTHERN PLAINS. DID TRY TO THIN THE
CLOUDS SOMEWHAT OVER THE NORTHERN HALF OF THE CWA AND MORE TOWARDS A
PARTLY-MOSTLY CLOUDY SKIES AS THEY WILL BE FARTHER AWAY FROM THE
MOISTURE STREAMING NORTHEAST. GETTING A HANDLE ON THESE HIGH CLOUDS
ON THE NORTH SIDE OF DECAYING CONVECTION IS ALWAYS TRICKY AND IT
COULD HAVE AN INFLUENCE ON THE HIGHS TODAY...ESPECIALLY IF THERE
ARE BREAKS IN THE CLOUDS OR THEY ARE LESS THICK THAN EXPECTED.
SINCE NORTHEAST FLOW WILL KEEP COOLER AIR ALOFT FLOWING OVER THE
AREA...STILL EXPECT TEMPS TO BE BELOW NORMAL AND IN THE 30S FOR
MOST LOCATIONS. DID TREND TEMPS UP A TOUCH BASED OFF A GENERAL
CONSENSUS OF SLIGHTLY WARMER TEMPS AND MAYBE MORE OF A FILTERED
SUNSHINE. IF THE CLOUDS AREN/T AS THICK AS EXPECTED...DAY SHIFT WILL
NEED TO BUMP TEMPS UP A COUPLE DEGREES.
AREA WILL BE BETWEEN SYSTEMS THIS EVENING...AS A WEAK UPPER RIDGE
SLIDES OVER AHEAD OF THE UPPER TROUGH IN THE CENTRAL PLAINS. WITH
THE DRY MID LEVEL AIR WILL STILL BE IN PLACE HAVE TRENDED TOWARDS A
DRIER FORECAST THAT MOST OF THE HIGHER RESOLUTION MODELS ARE
SHOWING. DRY AIR WILL BEGIN TO GIVE WAY TOWARDS THE WISCONSIN BORDER
LATE TONIGHT...AS THE UPPER LOW BEGINS TO LIFT NORTHEAST TOWARD THE
GREAT LAKES AND 850-700 WARM AIR ADVECTION AND MOISTURE INCREASE.
BUT...THINK THERE WILL BE ENOUGH DRY AIR TO DELAY THE START OF THE
PRECIPITATION TO BE A LITTLE LATER THAN THE 00Z GFS/ECMWF ARE
INDICATING AND MORE INTO THURSDAY. FINALLY...THERE ARE SOME HINTS AT
NORTHEAST FAVORED UPSLOPE FLOW PRECIP ON THE HIGHER RESOLUTION
MODELS. BUT WITH THE MOISTURE VERY SHALLOW AND THE LOW CLOUDS
ALREADY CUTTING OUT EARLY THIS MORNING AT KSAW...WILL GO WITH DRY
CONDITIONS OVER THE NORTH CENTRAL AND KEWEENAW TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 552 AM EDT WED APR 10 2013
ATTENTION TURNS TO DEVELOPING STORM SYSTEM OVER THE CENTRAL
PLAINS/MID MS VALLEY AND HOW IT WILL IMPACT OUR FCST AREA FOR THU
INTO SATURDAY IT TRACKS THROUGH THE GREAT LAKES REGION. STILL PLENTY
OF MODEL UNCERTAINTY WITH THIS SYSTEM AS NEW 00Z ECMWF NOW TRENDING
TOWARD FASTER GFS SOLN. 00Z UKMET AND CANADIAN SOLNS LOOK LIKE MORE
OF A COMPROMISE BETWEEN SLOWER NAM AND FASTER GFS/ECMWF SOLNS.
SHORTWAVE RIDING FROM THE GULF COAST INTO THE OHIO VALLEY LATE
THURSDAY INTO THURSDAY NIGHT COULD ALSO THROW A WRENCH INTO THE SNOW
AMOUNTS FOR THIS FCST BY POSSIBLY ROBBING MOISTURE FROM CLOSED LOW
AND MAIN SHORTWAVE EXPECTED TO TRACK THROUGH THE UPPER GREAT LAKES.
FIRST INCLINATION IS TO SIDE WITH THE SLOWER SOLNS AS SHORTWAVE RDGG
AND ASSOC DRIER AIRMASS WILL INITIALLY BE IN PLACE OVER THE GREAT
LAKES. SLOWER MODEL SOLNS WOULD BRING PCPN (MAINLY IN THE FORM OF
SNOW) INTO SCNTRL UPR MI WED NIGHT AND THEN SLOWLY SPREAD SNOW NORTH
AND EAST MAINLY THU AFTERNOON INTO THU EVENING. WILL ALSO CONTINUE
TO MENTION POSSIBLE SLEET OVER SCNTRL PORTIONS THU INTO THU EVENING
AS NAM SNDGS SUGGEST A SHALLOW ABV FREEZING LYR ALOFT.
SNOW SHOULD BEGIN TO PICK UP LATE THU AFTERNOON AND ESPECIALLY INTO
THU NIGHT AS DPVA INCREASES AHEAD OF CLOSED LOW/MAIN SHORTWAVE
LIFTING NORTH INTO AREA. ASSOC DEEP LAYER Q-VECT CONV...STRONG
290-295K ISENTROPIC ASCENT AND 800 MB FGEN FORCING LIFTS INTO THE
AREA SHOULD ALSO SUPPORT MODERATE TO HEAVY SNOW. SNOW GROWTH AT
ONSET OF PCPN THU INTO THU EVENING WILL NOT BE AS FAVORABLE AS DGZ
WILL BE AOA 15 KFT AND BEST MODEL OMEGA WILL GENERALLY BE BLO THIS
LEVEL SO EXPECT SLR INITIALLY TO BE CLOSER TO 10/1. LATE THU NIGHT
INTO FRIDAY HOWEVER SNOW GROWTH SHOULD BECOME BETTER AS COLDER WRAPS
BACK INTO STORM SYSTEM AND PUSHES DGZ BLO 15 KFT AND INTO SOME OF
THE BETTER UPWARD LIFT (MODEL OMEGA) ASSOC WITH THE SYSTEM. BASED ON
QPF AMOUNTS RANGING FROM NEAR .2 INCH OVER THE NW CWA TO OVER .4
INCH OVER THE SE...WOULD EXPECT SNOW AMOUNTS THU NIGHT IN THE 3-6
INCH RANGE...WITH HIGHEST AMOUNTS OVER THE CNTRL PORTION OF THE CWA.
ANOTHER 2-6 INCHES WOULD BE POSSIBLE ON FRIDAY WITH THE GREATEST
AMOUNTS OVER THE HIGHER TERRAIN OF WRN MQT AND BARAGA COUNTIES WHERE
LAKE ENHANCEMENT AND UPSLOPE NE FLOW WILL BOOST SNOW TOTALS.
GIVEN CONSIDERABLE MODEL UNCERTAINTY ESPECIALLY WITH TIMING OF PCPN
AND ALSO POSSIBLE MOISTURE IMPACT OF SECONDARY SHORTWAVE RIDING
THROUGH THE OHIO VALLEY HAVE DECIDED AGAINST ISSUING A WATCH AT THIS
TIME. PRELIMINARY STORM TOTAL SNOWFALL WOULD PROBABLY ONLY SUPPORT A
WATCH FOR ONLY MQT-BARAGA COUNTIES ANYWAY...WHERE I HAVE TOTAL SNOW
ACCUMULATION...POSSIBLY EXCEEDING 10 INCHES OVER HIGHER TERRAIN
AREAS WEST OF MQT. INSTEAD WILL ISSUE AN SPS AT THIS TIME SO I CAN
INCLUDE THE ENTIRE CWA UNDER ONE STATEMENT AND STILL CONVEY MORE
UNCERTAINTY WITH TIMING OF STORM AND SNOW AMOUNTS.
BY LATE FRI NIGHT INTO SAT...EXPECT LAKE ENHANCED SNOW TO GENERALLY
TAPER OFF AS MODELS SHOW CLOSED LOW LIFTING NE OF LAKE SUPERIOR AND
FORCING WEAKENING OVER THE AREA. LINGERING MOISTURE AND CYCLONIC
N-NW FLOW WILL STILL SUPPORT SCT SNOW SHOWERS FOR NCNTRL AND NE
PORTIONS OF THE CWA INTO SAT MORNING. SHORTWAVE RIDGE BUILDING IN
FROM THE WEST AND ASSOC SUBSIDENCE SHOULD ALLOW FOR DRY CONDITIONS
AND PARTIAL CLEARING LATE SAT AFTERNOON INTO SAT NIGHT.
ECMWF AND CANADIAN MODELS STILL ON BOARD SHOWING NEXT SHORTWAVE
EMERGING OUT THE NRN PLAINS AND BRINGING A SURGE OF WARM ADVECTION
PCPN INTO THE AREA FOR MAINLY SUN AFTERNOON INTO SUNDAY NIGHT. 00Z
GFS HAS NOW ABANDONED THIS IDEA AFTER SHOWING IT IN PREV RUNS. FOR
NOW WILL TREAT GFS SOLN AS AN OUTLIER AND MAINTAIN GOING FCST OF
HIGH CHC TO LIKELY POPS FOR RAIN/SNOW MIX SUN INTO SUN NIGHT. MIXED
PCPN WILL TAPER OFF TO ISOLD/SCT SHOWERS OR JUST END ON MONDAY AS
BEST ISENTROPIC LIFT SHIFTS SE OF THE AREA. HUDSON BAY HIGH PRESSURE
NOSING IN OVER THE UPPER GREAT LAKES WILL PROVIDE DRIER BUT
CONTINUED UNSEASONABLY COOL CONDITIONS FOR UPPER MICHIGAN MON NIGHT
INTO TUE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 138 AM EDT WED APR 10 2013
DRIER AIR WILL CONTINUE TO AFFECT ALL SITES AND CONTINUE THE VFR
CONDITIONS THROUGH THE PERIOD AS HIGH CLOUDS FROM STORM SYSTEMS
PASSING BY TO THE SOUTH MOVE THROUGH.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 552 AM EDT WED APR 10 2013
A LOW PRESSURE SYSTEM SLOWLY MOVING OUT OF THE CENTRAL PLAINS WILL
COMBINE WITH A HIGH PRESSURE IN CENTRAL CANADA TO LEAD TO A STRONG
PRESSURE GRADIENT OVER LAKE SUPERIOR FOR THE NEXT COUPLE OF DAYS.
THIS PRESSURE GRADIENT WILL LEAD TO INCREASING EAST-NORTHEASTERLY
WINDS TODAY AND TONIGHT...WITH WINDS IN THE 20-30KT RANGE TONIGHT.
EXPECT GALES TO 35KTS ON LATE TONIGHT INTO FRIDAY OVER
WESTERN LAKE SUPERIOR AND HAVE CONVERTED THE GALE WATCH TO A
WARNING FOR THAT TIME FRAME. ALSO ADDED A GALE WATCH FOR THE
REST OF THE LAKE FOR LATE THURSDAY NIGHT INTO FRIDAY AS THE
LOW TRACKS BY. SOME FREEZING SPRAY IS ALSO EXPECTED DURING THIS TIME
DUE TO THE COLDER TEMPERATURES OVER LAKE SUEPRIOR. AS THE LOW MOVES
INTO SOUTHERN QUEBEC ON FRIDAY AND FRIDAY NIGHT...EXPECT THE WINDS
TO SHIFT TO A MORE NORTHERLY DIRECTION AND THEY SHOULD DIMINISH TO
BELOW 30KTS BY THE EVENING. A WEAK HIGH PRESSURE RIDGE ON SATURDAY
WILL LEAD TO CONTINUED WEAKENING OF THE WINDS BEFORE INCREASING OUT
OF THE SOUTHEAST ON SUNDAY AHEAD OF ANOTHER LOW PRESSURE SYSTEM.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY AFTERNOON FOR
LSZ264>267.
GALE WARNING FROM 2 AM EDT /1 AM CDT/ THURSDAY TO 2 PM EDT /1 PM
CDT/ FRIDAY FOR LSZ162-263.
LAKE MICHIGAN...
GALE WARNING FROM 5 AM THURSDAY TO 6 AM EDT FRIDAY FOR LMZ221-
248-250.
&&
$$
SHORT TERM...SRF
LONG TERM...VOSS
AVIATION...07
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
138 AM EDT WED APR 10 2013
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 444 PM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOWS OVER
HUDSON BAY AND THE THE CENTRAL ROCKIES AND A RIDGE OVER THE SE CONUS
LEAVING CONFLUENT WRLY FLOW THROUGH NRN MN INTO NRN LAKE SUPERIOR.
AT THE SFC... A TROUGH STRETCHED THROUGH CNTRL KS INTO SRN IA FROM
LOW PRES OVER WRN TX. A WARM FRONT EXTENDED FROM SRN IA AND NRN IL
INTO NRN OH. NRLY FLOW HAD INCREASED THROUGH UPPER MI BEHIND A COLD
FRONT AS HIGH PRES OVER SASK BUILDS TOWARD NRN ONTARIO.
A LARGE AREA OF RAIN FROM CNTRL WI INTO FAR SRN UPPER MI WAS
SUPPORTED BY UPPER LEVEL DIV WITH THE RIGHT ENTRANCE OF A 150KT
250-300 MB JET STREAK OVER NRN ONTARIO AND LOWER LEVEL RESPONSE WITH
300K-305K (750-650 MB) ISENTROPIC ASCENT NORTH OF THE WARM FRONT.
THE PCPN AMOUNTS HAVE BEEN LIMITED AS AN MCS THROUGH SRN WI HAS
REDUCED MOISTURE INFLOW TO THE NORTH.
TONIGHT INTO WED...
ALTHOUGH THE FIRST BATCH OF PCPN OVER SRN UPPER MI
WILL MOVE OFF TO THE EAST THIS EVENING ANOTHER WEAK SHORTWAVE
EMERGING FROM THE PLAINS COMBINED ANOTHER INCREASE IN UPPER LEVEL
JET RIGHT ENTRANCE UPPER LEVEL DIV AND CONTINUED ISENTROPIC ASCENT
OVER THE REGION IS EXPECTED TO BRING ANOTHER ROUND OF PCPN
OVERNIGHT INTO WED MORNING. THERE IS SOME UNCERTAINTY WITH THE
TIMING AS THE GFS MOVES THE PCPN OUT MORE QUICKLY THAN THE
NAM/GEM/ECMWF.
SINCE THE THERE WAS PROMINENT LOWER LEVEL (285-290K ISENTROPIC
DESCENT) WITH DRIER AIR FLOWING TOWARD THE REGION HIGHER POPS WERE
LIMITED TO THE FAR SOUTH WITH A SHARP GRADIENT TO THE NORTH. NAM
TEMP PROFILE WITH A 1C-2C LAYER BETWEEN 800-700 MB SUGGESTS THAT
SLEET WILL BE THE PREDOMINANT PCPN TYPE IN THE AREA OF GREATEST QPF
WITH MAINLY SN/PL ON THE NRN EDGE. SOME FZRA MAY ALSO BE POSSIBLE
BUT SHOULD BE LESS SIGNIFICANT GIVEN THE SMALL WARM AREA ON THE FCST
SOUNDINGS.
CLOUDS/WIND SHOULD REDUCE DIURNAL TEMP RANGE. TEMPS ARE EXPECTED TO
REMAIN JUST AT OR BELOW FREEZING OVER THE SOUTH AND IN THE UPPER 20S
TO AROUND 30 OVER THE NORTH TONIGHT WITH HIGHS WED ONLY IN THE MID
30S.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 444 PM EDT TUE APR 9 2013
MUCH OF THE ATTENTION OF THIS FORECAST WILL BE ON THE UPCOMING
WINTER WEATHER EXPECTED THURSDAY THROUGH THE START OF THE WEEKEND.
FOR HYDROLOGICAL CONCERNS...THERE IS STILL 10-30 PLUS INCHES OF SNOW
STILL ON THE GROUND OVER THE MUCH OF THE HIGHER TERRAIN OF NORTHERN
UPPER MICHIGAN /SEE THE LATEST RTP OR NOHRSC SNOW ANALYSIS PAGE/.
ALTHOUGH WE WILL BE ADDING PRECIPITATION ON TOP OF THE SNOWPACK...A
QUICK MELT IS NOT FORESEEN AT THIS TIME...WITH TEMPERATURES FORECAST
TO REMAIN BELOW NORMAL THROUGH AT LEAST THE WEEKEND.
WEDNESDAY NIGHT WILL START OFF WITH STRONG HIGH PRESSURE SET UP
ACROSS ONTARIO...INFLUENCING MUCH OF OUR WEATHER INITIALLY WITH DRY
ENE FLOW FUNNELING IN FROM EASTERN ONTARIO. WENT AHEAD AND SLOWED
DOWN THE APPROACHING MOISTURE FROM THE SOUTHWEST ONCE AGAIN.
SOUTH CENTRAL UPPER MICHIGAN WILL CONTINUE TO BE RIGHT ALONG THE
NORTHERN PRECIPITATION SHIELD THROUGH MID MORNING THURSDAY. BY 18Z
THURSDAY THE SFC LOW SHOULD BE SET UP ACROSS SOUTHERN
WISCONSIN/NORTHERN ILLINOIS AND INDIANA.
AT THIS POINT THE BEST OPTION LOOKS TO FOLLOW A BLEND BETWEEN THE
12Z ECMWF AND NAM...WITH LESS INCLUSION OF THE QUICKER GFS.
CONFIDENCE IS INCREASING ON THE IDEA OF STRONG STRONG EAST TO
NORTHEASTERLY WINDS WEDNESDAY NIGHT THROUGH THURSDAY
EVENING...PARTICULARLY NEAR ESC AND MNM AND WESTERN LAKE SUPERIOR.
THE GFS...GIVEN THE WEAKER AND SFC LOW CENTERED FARTHER TO THE EAST
IS UNDERSTANDABLY LIGHTER WITH THE WIND FORECAST...BUT WILL HAS
30-35KT WINDS OVER FAR SW LAKE SUPERIOR AND OUR EASTERN LAKE
MICHIGAN ZONES.
SNOWFALL AMOUNT WITH THIS SYSTEM CONTINUE TO BE A CONCERN.
HOWEVER...WITH AS MUCH MODEL SPREAD STILL SHOWN...WILL NOT ISSUE ANY
SNOW HEADLINES...BUT CONTINUE TO MENTION THE POTENTIAL IN THE HWO.
THE 12Z ECMWF HAS BECOME MORE PROGRESSIVE...EJECTING THE 500MB LOW
TO EASTERN ONTARIO SATURDAY MORNING...OR 6-12 HOURS FASTER THAN THE
09/00Z RUN. THIS IS STILL QUITE A BIT SLOWER THAN THE MERGING GFS
SOLUTION...WITH THE LOW MOVING AS CLOSE AS CENTRAL LOWER
MICHIGAN...WHILE THE NAM/GFS TRACK IT ACROSS UPPER MICHIGAN. THE
09/12Z CANADIAN INITIALLY LOOKS TO BE A GOOD COMPROMISE BETWEEN THE
2 CAMPS...BUT IS MUCH WEAKER WITH LESS THAN A QUARTER INCH OF LIQUID
ACROSS THE MUCH OF THE CWA. THE GFS DOES NOT DO MUCH BETTER...WITH A
GOOD DRY LAYER SHOWING UP ON THE FCST SOUNDINGS BETWEEN 900 AND
700MB. SNOWFALL AMOUNTS COULD VARY SIGNIFICANTLY...BUT STILL EXPECT
3-6 INCHES OF WET SNOW OR MORE ACROSS MUCH OF THE AREA...WITH SNOW
RATIOS 10-15:1. WILL CONTINUE TO FINE TUNE THE FORECAST TONIGHT AND
TOMORROW.
FEW CHANGES WERE MADE TO THE MODEL CONSENSUS BEYOND FRIDAY...OTHER
THAN TO CONTINUE TO HIGHLIGHT THE NORTHERN UPSLOPE AREAS FOR
POSSIBLE LINGERING SNOW/SNOW SHOWERS INTO SATURDAY. THE ACTIVE
WEATHER PATTERN WILL CONTINUE WITH THE NEXT ROUND SLIDING IN TOWARD
SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 138 AM EDT WED APR 10 2013
DRIER AIR WILL CONTINUE TO AFFECT ALL SITES AND CONTINUE THE VFR
CONDITIONS THROUGH THE PERIOD AS HIGH CLOUDS FROM STORM SYSTEMS
PASSING BY TO THE SOUTH MOVE THROUGH.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 444 PM EDT TUE APR 9 2013
TONIGHT THROUGH THURSDAY...LAKE SUPERIOR WILL REMAIN BETWEEN LOW
PRESSURE TO THE SOUTH...AND HIGH PRESSURE TO THE NORTH. PRES
GRADIENT BETWEEN THESE FEATURES WILL LEAD TO N WINDS TO AROUND 25 KT
TUE INTO WED. NE WINDS ARE EXPECTED TO INCREASE TO GALES TO 35 KT
WED NIGHT INTO THU NIGHT...MAINLY OVER THE WEST...BEFORE DIMINISHING
BACK TO 25 KT ON FRIDAY. WINDS ARE EXPECTED TO DIMINISH BLO 20 KTS
FRI NIGHT INTO SAT AND HIGH PRES BUILDS IN FM THE WEST.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
GALE WATCH FROM LATE TONIGHT THROUGH THURSDAY EVENING FOR LSZ162-
263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GAYLORD MI
118 AM EDT WED APR 10 2013
.SYNOPSIS...
ISSUED AT 435 PM EDT TUE APR 9 2013
UNSETTLED WEATHER WILL CONTINUE FOR THE REST OF THE WORK WEEK...AS
SEVERAL WAVES OF LOW PRESSURE TRACK ALONG A STALLED FRONTAL BOUNDARY
DRAPED ACROSS THE LOWER LAKES. RAIN WILL CONTINUE FOR TONIGHT...WITH
A BRIEF BREAK IN THE ACTION POSSIBLE EARLY WEDNESDAY MORNING. BUT
THEN ADDITIONAL PRECIPITATION MOVES IN FOR THE DURATION OF THE
WEEK. WITH COLDER AIR ENTERING THE PICTURE...A WINTRY MIX OF SNOW
AND SLEET IS EXPECTED FOR MANY AREAS BY THURSDAY...WITH
ACCUMULATION POSSIBLE. THE CHILLY WEATHER WILL CONTINUE INTO NEXT
WEEK.
&&
.UPDATE...
ISSUED AT 118 AM EDT WED APR 10 2013
GOING FORECAST LOOKS IN DECENT SHAPE...BUT HAVE SPED UP ARRIVAL
TIME OF NEXT INCOMING PRECIP SHIELD BASED ON LATEST RADAR TRENDS.
PER RAP FORECAST RAOBS...PRECIP TYPE SHOULD BE MAINLY RAIN SOUTH
OF M-72...BUT WILL PROBABLY MIX WITH SLEET WITH NORTHWARD
EXTEND. MORE OF A SNOW/SLEET COMBO IS LIKELY UP TOWARD THE M-32
CORRIDOR WHERE COLDER AIR IS BECOMING INCREASINGLY ENTRENCHED.
COULD ALSO SEE A LOW END FREEZING RAIN THREAT AT THE ONSET UP
TOWARD M-32/HIGHER TERRAIN WHERE TEMPS ARE CURRENTLY RIGHT AROUND
32F. DON`T EXPECT MUCH IF ANY PRECIP NORTH OF THERE AS DRIER AIR
IS WINNING THE BATTLE...WITH CLOUDS EVEN BEGINNING TO THIN PER
LATEST SATELLITE TRENDS.
UPDATE ISSUED AT 1011 PM EDT TUE APR 9 2013
WIDESPREAD RAIN FROM THIS AFTERNOON/EARLY EVENING HAS MOSTLY EXITED
OUR CWA...WITH ONLY A NARROW BAND OF RAIN REMAINING ALONG THE M-32
CORRIDOR. ADDITIONAL SHOWERS HAVE EXPANDED NORTH OF THE WARM FRONT
BUT REMAIN SOUTH OF M-55 ATTM. STRONGER BATCH OF CONVECTION
CONTINUES TO FIRE UPSTREAM OVER SRN MINNESOTA AND IOWA NORTH OF
THE SURFACE LOW. SO FAR...NAM HAS HAD A DECENT HANDLE ON TIMING OF
QPF AND OF LOCATIONS OF HIGHEST QPF...BUT OVER MICHIGAN AND
UPSTREAM OVER THE UPPER MISSISSIPPI VALLEY. LATEST NAM STILL SHOWS
SCATTERED SHOWERS RIDING ALONG OUR SRN COUNTIES OVERNIGHT...THEN
SURGING NORTHWARD AGAIN BY AROUND 09Z. WITH THIS NEXT BATCH OF
PRECIP...COLD NE FLOW WILL LEND TO THE DEVELOPMENT OF MIXED PRECIP
ON THE NRN EDGE...MAINLY NORTH OF M-72. AT THIS POINT...APPEARS
THAT MIXED PRECIP ALONG THIS NRN EDGE OF THE PRECIP SHIELD WILL BE
RATHER SCATTERED AND LIGHT AND TEMPS WILL BE RIGHT AROUND
FREEZING. SO IT IS DIFFICULT TO SAY WHETHER OR NOT IT WILL CAUSE
ANY TRAVEL PROBLEMS. AT THIS POINT...WILL NOT ISSUE ANY HEADLINES
AND WILL PLAY THE WAIT AND SEE GAME.
UPDATE ISSUED AT 745 PM EDT TUE APR 9 2013
WIDESPREAD RAIN IS GRADUALLY DIMINISHING FROM SW TO NE ACROSS NRN
LWR MICHIGAN THIS EVENING...WITH ONLY SCATTERED SHOWERS LINGER
ACROSS OUR FAR SRN COUNTIES ALONG AND SOUTH OF M-55. DIMINISHING
PRECIP IS JUST A BIT AHEAD OF SCHEDULE...AND WILL MAKE SOME
ADJUSTMENTS TO WX/POP TIMING AS A RESULT. OTHERWISE...STILL
APPEARS OUR NEXT BATCH OF (MIXED) PRECIP WILL ARRIVE ACROSS OUR SW
COUNTIES BY 09Z...AND THEN SPREAD THRU THE REST OF NRN LWR
MICHIGAN THRU 12Z.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 435 PM EDT TUE APR 9 2013
...GRADUALLY COOLING TEMPERATURES ALOFT WILL BRING INCREASING
AMOUNTS OF WINTRY PRECIPITATION TO NORTHERN MICHIGAN...
HIGH IMPACT WEATHER POTENTIAL: SOME SLICK TRAVEL POSSIBLE FROM M-32
SOUTH TO M-72 BEGINNING DAYBREAK WEDNESDAY AND CONTINUING THROUGH
NOON.
OVERVIEW: EARLY AFTERNOON WATER VAPOR IMAGERY REVEALS QUITE THE
ACTIVE PATTERN ACROSS THE CONUS WITH LONGWAVE TROUGHING ALONG THE
ROCKY MOUNTAIN AXIS HELPING PUMP AMPLE GULF MOISTURE NORTH ACROSS A
WEST TO EAST ORIENTED BAROCLINIC ZONE LOCATED NEAR THE MI/IN/OH
BORDER...WHICH BASICALLY SEPARATES MID SPRING TO THE SOUTH FROM LATE
WINTER TO THE NORTH. NORTH OF THIS BOUNDARY...NORTHERN STREAM
SHORTWAVE IS ADVANCING RAPIDLY EAST THROUGH ONTARIO WITH AN
IMPRESSIVE 150KT JET STREAK ON ITS SOUTHERN FLANK. BEHIND THIS
FEATURE/JET MAX...MID LEVEL HEIGHT RISES AND CONCOMITANT SURFACE
PRESSURE RISES ALONG WITH AGEOSTROPHIC NORTHERLY LLEVEL FLOW
REARWARD FROM DEPARTING JET STREAK ARE ALL CONSPIRING TO GRADUALLY
ALLOW COOLING BOUNDARY LAYER TEMPERATURES TO OOZE SOUTH FROM CENTRAL
CANADA. THIS COOLING LLEVEL AIR WILL INCREASINGLY COMPLICATE THE
FORECAST OF PRECIPITATION TYPE GOING FOREWORD...WITH INCREASING
WEATHER IMPACTS LIKELY THROUGH THE SHORT TERM PORTION OF THE
FORECAST.
THROUGH THIS EVENING: TRACKING MCS REMNANTS NOW BEGINNING TO CROSS
LAKE MICHIGAN...HELPING REINFORCE INITIAL RAINFALL BAND THAT ARRIVED
EARLIER THIS AFTERNOON. THIS WILL BRING A DECENT SHOT OF RAINFALL
THROUGHOUT NORTHERN LOWER THROUGH THIS EVENING. LIKELY LOOKING AT
0.1-0.3" OF LIQUID THROUGH 00Z BEFORE BACK EDGE RAPIDLY MOVES EAST.
TEMPERATURES SLOWLY FALL INTO THE UPPER 30S.
TONIGHT: INITIAL MCS REMNANTS HEAD EAST...ENDING RAINFALL FROM WEST
TO EAST TO BEGIN THE PERIOD. ATTENTION TURNS TO NEXT WRINKLE IN THE
MID LEVEL FLOW...NOW EVIDENT OVER CENTRAL SOUTH DAKOTA AND
NEBRASKA...RESPONSIBLE FOR DEVELOPING CONVECTION ATTM. THIS FEATURE
WILL PUSH NORTH AND EAST...COAXING ANOTHER SURGE IN THE H8 LLJ TO
ITS SOUTH AND EAST...AND WITH PRECIPITATION ASSOCIATED WITH THIS
CONVECTION EASILY SURVIVING ITS TRIP EAST GIVEN THIS MOIST INFLOW
AND DOWNSTREAM SUPPORT FROM NEARLY STATIONARY 150KT JET MAX ON THE
1.5 PVU SURFACE. TRENDS IN THE HIGHER RESOLUTION GUIDANCE SUGGEST A
SLOWER ARRIVAL TO THIS FEATURE WITH MOST OF THE NIGHT /SAVE THE VERY
START AND VERY END/ LIKELY ENDING UP DRY. LLEVEL MOISTURE
THINS...WHICH SUGGESTS SOME POTENTIAL FOR DRIZZLE...PRIMARILY
ALONG-SOUTH OF M-32 WITH FURTHER DRYING MAKING THIS QUITE UNLIKELY
FURTHER NORTH.
PTYPE: CERTAINLY RAIN TO START THE EVENING. WILL FOLLOW GRIDDED LAMP
GUIDANCE CLOSELY FOR THE OVERNIGHT...WHICH SUGGEST THAT AT THE
SURFACE...TEMPERATURES WILL NOT NEAR FREEZING UNTIL JUST BEFORE
DAYBREAK...AND ONLY OVER EASTERN UPPER AND THE HIGHER TERRAIN OF
NORTHERN LOWER NORTH OF M-72. UPSTAIRS...COOLING THROUGH THE COLUMN
SUGGESTS MIX POTENTIAL BEGINS AFTER MIDNIGHT...GRADUALLY PROGRESSING
SOUTH WITH TIME. BY THE TIME PRECIPITATION ARRIVES TOWARDS
DAYBREAK...EXPECT SOME SLEET AS FAR SOUTH AS THE M-72 CORRIDOR...
WITH SNOW AND SLEET ALONG/NORTH OF THE M-32 CORRIDOR. IN
BETWEEN...SOME ISOLATED FZRA LOOKS POSSIBLE IF PRECIPITATION CAN GET
GOING BEFORE DAYBREAK. PRECIPITATION AMOUNTS THROUGH DAYBREAK LOOK
QUITE LIGHT FOR LOCATIONS WHERE FREEZING/FROZEN PRECIPITATION IS
POSSIBLE. SO...CURRENT EXPECTATIONS ARE THAT FOLKS IN THE BAND
BETWEEN M-32 AND M-72 MAY EXPERIENCE A FEW SLICK SPOTS TOWARDS
DAYBREAK.
TEMPERATURES: FALLING INTO THE LOWER-MID 30S CWA-WIDE.
WEDNESDAY: PRECIPITATION SPREADS ACROSS MUCH OF NORTHERN LOWER TO
START THE DAY...WITH SIMILAR PRECIPITATION TYPE CONCERNS /SEE
BELOW/. BY AFTERNOON...HOWEVER...LLJ OVER SOUTHERN LOWER SHIFTS EAST
WITH VEERING LLEVEL FLOW DIMINISHING FORCING OVER THE NEARBY
BAROCLINIC ZONE. THE RESULT LOOKS TO BE IMPROVING CONDITIONS FOR
THE AFTERNOON WITH LIKELY POPS RESTRICTED TO AREAS SOUTH OF M-55.
PTYPE: THE ATMOSPHERIC COLUMN COOLS JUST SLIGHTLY DURING THE DAY...
BUT GENERALLY TEMPS REMAINING NEARLY UNCHANGED. THE IMPORTANT
DIFFERENCE FROM THE PRE-DAWN HOURS WILL BE SOLAR INSOLATION...WHICH
WILL LIKELY HELP MORNING TEMPERATURES RISE ABOVE FREEZING...EVEN
IN THE COOL SPOTS OF NORTHERN LOWER. THUS...AFTER SOME DAYBREAK
FREEZING RAIN CONCERNS OVER INTERIOR NORTHERN LOWER...THIS LOOKS
TO TRANSITION TO MORE OF A SNOW/SLEET/RAIN SCENARIO...WITH THE
DIVIDING LINE LIKELY NEAR OR A LITTLE NORTH OF M-72. NORTH OF THIS
LINE...EXPECT SNOW/SLEET...WITH SLEET/RAIN TO THE SOUTH EXCEPT ALL
RAIN ALONG/SOUTH OF M-55. THE FURTHER NORTH YOU GO...HOWEVER
...PRECIPITATION AMOUNTS WILL QUICKLY DWINDLE. SO...EXPECT ONLY
MINOR SNOW/SLEET ACCUMULATIONS NORTH OF M-72...WITH A COATING TO
PERHAPS 1 INCH ALONG M-32. IMPACTS LOOK GENERALLY QUITE
MINOR...WITH ANY SLICK SPOTS LIKELY ENDING BY LATE MORNING AS
SURFACE TEMPERATURES WARM.
TEMPERATURES: 35-40F AREA-WIDE...10-15F BELOW SEASONAL NORMS.
HEADLINES: IMPACTS DO NOT LOOK VERY SIGNIFICANT WITH LOW CONFIDENCE
ON LOCATION AND TIMING. CAN/T RULE OUT THE NEED FOR A SMALL WINTER
WEATHER ADVISORY FOR THE MORNING HOURS...BUT AT THIS POINT...I DON/T
SEE THE IMPACTS RISING TO THIS LEVEL. RATHER...WILL ISSUE A SPECIAL
WEATHER STATEMENT HIGHLIGHTING THE POTENTIAL FOR SLICK SPOTS THROUGH
TOMORROW MORNING.
&&
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 435 PM EDT TUE APR 9 2013
RECENT TRENDS: TEMPERATURES...3-4C BELOW NORMAL FOR FIRST 8 DAYS OF
APRIL AS EARLY MONTH COLD BLANKETS MUCH OF CANADA AND CENTRAL/
EASTERN U.S.. PRECIP/HYDROLOGY...ABOVE NORMAL PRECIP TO START APRIL
ACROSS EASTERN UPPER (ESPECIALLY ADJACENT TO LAKE SUPERIOR)...LESS
THAN 50 PERCENT OF NORMAL ACROSS MUCH OF NORTHEAST LOWER. 30 DAY
STANDARDIZED PRECIP INDEX ALSO DRIER THAN NORMAL ACROSS NORTHEAST
AND MUCH OF SOUTHERN LOWER. REMAINING SNOW COVER ACROSS EASTERN
UPPER AND US-131 CORRIDOR IN NORTHWEST LOWER...POCKETS OF 12+ INCHES
STILL ACROSS CHIPPEWA COUNTY. AREA RIVERS SHOWING SOME UPWARD
RESPONSE TO YESTERDAY`S RAINFALL...RIFLE RIVER NEAR STERLING HAS
RISEN NEARLY 2 FEET/24H AND IS APPROACHING ACTION STAGE (RADAR
PRECIP ESTIMATES FROM NMQ SHOW 0.50-0.75 INCH RAINFALL OVER THE
BASIN PAST 24H). GREAT LAKES...WATER TEMPERATURES AROUND 1C EASTERN
LAKE SUPERIOR...1-2C NORTHERN LAKES MICHIGAN/HURON. LATEST
PROJECTED LAKE LEVELS FOR MICHIGAN-HURON HUG RECORD LOWS THROUGH THE
SUMMER.
LARGE SCALE PATTERN/FORECAST: FIVE WAVE HEMISPHERIC PATTERN WITH
MEAN LONG WAVE TROUGH ENCOMPASSING MUCH OF NORTH AMERICA...NEAR
NEUTRAL ATLANTIC TELECONNECTIONS WITH THE PACIFIC VALUES SPIKING
SINUSOIDALLY (-WPO/+EPO/-PNA). THE UPSHOT OF THIS IS BLOCKING
ACROSS THE CENTRAL PACIFIC WITH TROUGHING TO THE EAST. SPLIT FLOW
ACROSS WESTERN NORTH AMERICA WITH SHORT WAVE ENERGY BOTTOMING OUT
OVER THE FOUR CORNERS REGION. THIS TROUGH WILL MAKE ITS WAY ACROSS
THE MIDWEST DURING THE LATTER HALF OF THE WEEK...WHILE ADDITIONAL
JET ENERGY DIGS SOUTHEAST FROM THE NORTHEAST PACIFIC HELPING TO
MAINTAIN NORTH AMERICAN LONG WAVE BUT WITH A SHIFT IN THE AXIS INTO
THE WESTERN STATES. A PATTERN THAT IS POTENTIALLY A LITTLE WARMER
FOR THE GREAT LAKES BUT ALSO AN ACTIVE ONE.
IN THE SHORTER TERM...AS UPPER TROUGH EMERGES ONTO THE PLAINS...LOW
PRESSURE WILL DEVELOP ALONG AN ELONGATED BOUNDARY STRETCHING FROM
THE OHIO VALLEY INTO THE MIDDLE/LOWER MISSISSIPPI VALLEY. CURRENT
THINKING ON SURFACE LOW TRACK WILL RUN FROM MISSOURI-NORTHERN
ILLINOIS...THEN OCCLUDE AND GET STRETCHED OUT BY THURSDAY
NIGHT/FRIDAY. SOME UNCERTAINTY AS TO EVOLUTION OF SECONDARY LOW
DEVELOPMENT OVER THE LOWER GREAT LAKES BY FRIDAY...WILL BE DEPENDENT
ON HOW UPPER LEVEL WAVE EVOLVES WITH GFS/GGEM IN ONE CAMP (QUICKER
UPPER WAVE/STRONGER SECONDARY DEVELOPMENT) AND NAM/ECMWF SLOWER WITH
UPPER WAVE WITH SECONDARY DEVELOPMENT NOT AS DRAMATIC. FORECAST
WILL SIDE WITH THE LATTER IDEA...WITH THE OCCLUDING SYSTEM LIFTING
NORTHEAST INTO MICHIGAN FRIDAY. FORECAST PROBLEMS THROUGH FRIDAY
WILL DEAL WITH PRECIPITATION TYPE AND AMOUNT ISSUES...WITH LOW/MID
LEVEL DEFORMATION AXIS LIKELY TO RESULT IN A SHARP GRADIENT BETWEEN
AREAS THAT RECEIVE PRECIPITATION AND WHICH DON`T...WHILE EAST/
NORTHEAST LOW LEVEL FLOW PUSHES COOLER/DRIER AIR IN FROM ONTARIO
WHICH WILL IMPACT PRECIP TYPE.
WEDNESDAY NIGHT THROUGH FRIDAY: SURFACE LOW FORECAST TO BE IN THE
VICINITY OF NORTHEAST MISSOURI/WESTERN ILLINOIS WEDNESDAY
EVENING...WITH A WARM/STATIONARY FRONT EXTENDING EAST ACROSS
INDIANA/OHIO. ENTRANCE REGION OF A 140+KT JET STREAK OVER NORTHERN
ONTARIO WILL GIVE THINGS A BOOST WITH GOOD LOW LEVEL MOISTURE
TRANSPORT/CONVERGENCE INTO THE BOUNDARY ACROSS SOUTHERN
WISCONSIN/SOUTHERN LOWER MICHIGAN (PRECIPITABLE WATER VALUES OVER AN
INCH). MID LEVEL CONFLUENCE AXIS WILL BE SET UP ACROSS THE UPPER
PENINSULA...GIVE OR TAKE A COUPLE DEGREES LATITUDE THOUGH EXACTLY
WHERE THIS SETS UP WILL HAVE BIG IMPACTS ON NORTHERN MICHIGAN
WEATHER. WILL TRY TO REFINE THE DETAILS A BIT MORE HERE...DOES
APPEAR THAT THE FOCUS FOR HEAVIER QPF WILL BE SOUTH OF THE FORECAST
AREA AS POSITION OF DEFORMATION AXIS ALLOWS DOWNWARD BRANCH OF
FRONTOGENETIC SECONDARY CIRCULATION TO BE FOCUSED ON NORTHERN LOWER
MICHIGAN. WILL CONTINUE WITH THE TREND OF KEEPING PRECIP OUT OF
EASTERN UPPER...AND GRADUATE POPS FROM NORTH TO SOUTH BELOW THE
BRIDGE WITH MAXIMUM QPF AROUND 0.50 INCH ALONG/SOUTH OF THE M-55
CORRIDOR. PRECIP TYPE STILL NOT EXACTLY STRAIGHTFORWARD AS THERE
WILL BE A GRADIENT OF SNOW (ALONG/NORTH M-32) TO SNOW/SLEET/RAIN
(FREEZING RAIN?) M-32 TO M-55...AND MAINLY RAIN SOUTH OF THE M-55
CORRIDOR. NOT PLANNING ON MUCH SNOW ACCUMULATION WEDNESDAY
NIGHT...WILL MENTION SOME LIGHT ICING BETWEEN M-72 AND M-55.
MIXED PRECIPITATION WILL BE ONGOING THURSDAY MORNING AS SYSTEM
BEGINS TO OCCLUDE...AND EXPECT PERIODS OF PRECIPITATION THROUGH THE
AFTERNOON (AND MAY PUSH FARTHER NORTH TOWARD THE UPPER PENINSULA
DURING THE AFTERNOON AS UPPER SYSTEM GETS CLOSER AND DEFORMATION
AXIS WEAKENS). PRECIP TYPE WILL CONTINUE TO BE TRICKY AS 850MB
THERMAL RIDGE LIFTS FARTHER NORTH ACROSS LOWER MICHIGAN. WILL ALLOW
PRECIP TO TRANSITION OVER TO MORE SLEET/RAIN/FREEZING RAIN BETWEEN
M-72 AND M-68 THURSDAY AFTERNOON. LIKE WEDNESDAY NIGHT WILL KEEP
SNOW AMOUNTS MINIMAL AS BEST SNOW CHANCES WILL (SHOULD) BE IN
LIGHTEST QPF AREAS (AND TEMPERATURES WILL BE NEAR OR A LITTLE ABOVE
FREEZING WITH THE DIURNAL HEATING CYCLE).
ANOTHER SURGE OF PRECIPITATION APPEARS LIKELY THURSDAY NIGHT AS LOW
LEVEL MOISTURE TRANSPORT AXIS IS MORE FOCUSED ON NORTHERN LOWER
MICHIGAN AS OCCLUDED BOUNDARY BENDS NORTHWARD INTO THE LOWER
PENINSULA. THIS SHOULD ALSO ALLOW EASTERN UPPER TO GET IN ON THE
ACT AS WELL AS DEEPER MOISTURE WRAPS BACK TO THE WEST. PRECIP TYPE
EXPECTED TO BE ALL SNOW ACROSS EASTERN UPPER AND THE TIP OF THE
MITT...TRANSITIONING TOWARD MORE SLEET/FREEZING RAIN FARTHER SOUTH
DURING THE EVENING...WHICH ITSELF IS EXPECTED TO HEAD MORE TOWARD
SNOW BY FRIDAY MORNING. PERIODS OF SNOW EXPECTED TO CONTINUE
FRIDAY. SNOW AMOUNTS ACROSS EASTERN UPPER AND THE TIP OF THE MITT
COULD END UP PUSHING AT LEAST ADVISORY CRITERIA THURSDAY NIGHT AND
FRIDAY (AND SHOULD BE ON THE HEAVY/WETTER SIDE FROM A SNOW RATIO
STANDPOINT).
OVERALL...LOOKS LIKE A REAL MESS AND DESPITE ALL THE DETAILS ABOVE
THERE WILL LIKELY BE CHANGES. WILL PROBABLY BE LOOKING AT VARIOUS
WINTER WEATHER ADVISORIES FOR A DRAWN OUT EVENT.
EXTENDED FORECAST (SATURDAY THROUGH TUESDAY): SHORT AND SWEET HERE
AFTER ALL THAT...WILL DRY THINGS OUT SATURDAY...RAIN MOVES IN LATER
SUNDAY/SUNDAY NIGHT/MONDAY WITH ANOTHER SHORT WAVE TROUGH/COLD
FRONT.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 118 AM EDT WED APR 10 2013
MVFR AND IFR CEILINGS CONTINUE AT THE MOMENT ACROSS THE TERMINAL
SITES...WHILE A BATCH OF PRECIPITATION IS CURRENTLY PUSHING ACROSS
WISCONSIN. THAT AREA OF PRECIP WILL ARRIVE AND IMPACT THE TVC/MBL
AND TO A LESSER EXTEND APN TERMINALS THROUGH SUNRISE...CONTINUING
THROUGH MID MORNING BEFORE ENDING FAIRLY QUICKLY NO LATER THAN
17Z. PRECIPITATION TYPE SHOULD BE MAINLY RAIN (MIXED WITH MAYBE A
LITTLE SLEET) AROUND MBL...WITH MORE OF A RAIN/SLEET COMBO FOR
TVC...AND A SNOW/SLEET MIX FOR APN. MORE PERIODS OF IFR ARE
POSSIBLE AS THIS PRECIPITATION ARRIVES. HOWEVER...IMPROVEMENT IS
EXPECTED FROM THE NORTH THROUGH THE DAY AS HIGH PRESSURE OVER
ONTARIO DRIVES DRIER AIR SOUTHWARD WITH TIME...WITH ALL SITES
MINUS MBL LIKELY EXPERIENCING CEILINGS LIFTING TO VFR...AS WINDS
BECOME GUSTY FROM THE NORTHEAST.
&&
.MARINE...
ISSUED AT 435 PM EDT TUE APR 9 2013
SUMMARY: WAVES OF LOW PRESSURE WILL MOVE ALONG A FRONT STALLED OVER
SOUTHERN MICHIGAN THROUGH WEDNESDAY. BEYOND THIS...LOW PRESSURE
DEVELOPING OVER THE MID MISSISSIPPI VALLEY WILL LIFT SLOWLY NORTH
AND EAST INTO THE GREAT LAKES...IMPACTING OUR WEATHER THROUGH FRIDAY
BEFORE HIGH PRESSURE BUILDS IN FOR THE COMING WEEKEND.
HEADLINES: SMALL CRAFTS FROM GTLM4 SOUTH LOOK GOOD GIVEN SLOWLY
STRENGTHENING NORTHEASTERLY WINDS TONIGHT. THIS WILL LIKELY NEED TO
BE EXPANDED TO AREAS FROM STURGEON POINT SOUTH COME LATER WEDNESDAY
GIVEN FURTHER STRENGTHENING TO THE NORTHEASTERLY WINDS. SMALL
CRAFTS WILL EXPAND TO ALL ZONES WEDNESDAY NIGHT AS AFOREMENTIONED
LOW PRESSURE BEGINS TO PUSH TOWARDS THE GREAT LAKES...WHICH WILL BE
NEEDED THROUGH WEEK/S END.
&&
.HYDROLOGY...
ISSUED AT 435 PM EDT TUE APR 9 2013
AS FOR HYDROLOGY...FORECAST QPF PUTS MANISTEE RIVER NEAR SHERMAN
AND RIFLE RIVER NEAR STERLING CLOSE TO FLOOD STAGE...TOTAL QPF
FROM TONIGHT THROUGH FRIDAY OF 1-2 INCHES ALONG AND SOUTH OF M-32.
DID CONSIDER A FLOOD WATCH BUT ISSUED A HYDROLOGIC OUTLOOK EARLIER
TODAY FOR THE TWO DATA POINTS...GOOD POSSIBILITY OF UPGRADING AT
LEAST STERLING TO A FLOOD WARNING WITH LATER RIVER FORECAST
ISSUANCES.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THURSDAY FOR LMZ344>346.
LS...NONE.
&&
$$
UPDATE...LAWRENCE
SYNOPSIS...KB
SHORT TERM...ARNOTT
LONG TERM...JPB
AVIATION...LAWRENCE
HYDROLOGY...JPB
MARINE...ARNOTT
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
414 PM CDT Wed Apr 10 2013
.SHORT TERM...(This Evening through Thursday)
Issued at 408 PM CDT WED APR 10 2013
Late This Afternoon through Thursday:
Can finally see the light at the end of the tunnel with respect to
the moderate rain and embedded convection. Latest satellite imagery
and radar data show a firm back edge to the post-frontal rain from
east-central KS through eastern OK. The entire region is lifting
northeastward at a fairly quick pace. The latest RAP mass fields/qpf
have the best handle on this and have sped up the ending time of the
rain over the CWA for this evening. While the moisture above h7 will
be stripped away by a pronounced dry slot, and thus putting an end
to the widespread rain, there will be relatively deep and nearly
saturated layer up through at least h8 so can`t rule out the
occasional sprinkle once the main rain band moves through.
The upper low and associated deep/positively tilted trough from the
Central High Plains through the Southern Rockies will continue to
influence our sensible weather through tomorrow. This feature is
expected to shift east while the low deepens over eastern NE/western
IA and the trough axis takes on a more neutral tilt. Am expecting
considerable low level moisture to remain trapped over the region
and provide a blanket of clouds through tomorrow. There will likely
be at least one mid level vorticity maxima that will rotate under the
primary upper low and track across eastern KS and northern MO on
Thursday. This feature could produce patches of light rain over much
of the CWA. However, the rain may be only enough to wet the pavement
south of Highway 36. North of this line will go with chance PoPs.
Will also need to consider some light snow over the northwest corner
of MO in the morning as progged soundings forecast just enough ice
crystals to support this threat.
As for temperatures will favor the consensus approach for overnight
lows while going under NAM/GFS MOS guidance due to the extensive
cloud cover and unseasonably cold airmass.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 408 PM CDT WED APR 10 2013
Thursday night through Wednesday...
The shortwave trough will gradually depart the region Thursday night
into Friday with cool temperatures remaining. Minimum temperatures
may drop to or a few degrees below freezing both Friday and Saturday
mornings, so those with agricultural interest or sensitive
vegetation concerns should closely monitor subsequent forecasts.
Otherwise, upper level ridging builds into the central portion of
the CONUS Saturday and Sunday, with southerly surface winds
returning. This will spell a notable warmup Saturday and especially
on Sunday, with maximum readings on Sunday reaching the 70s in many
locations. A shortwave trough will eject northeastward out of the
Northern Plains on Sunday with an associated cold front approaching
the CWA on Sunday. The forward progression of the front will be
hindered as the upper system moves quickly away from the area. This
frontal boundary will linger across or near the CWA Sunday afternoon
as the next shortwave trough enters the plains and follows a similar
track. With little overall change to the upper air pattern and the
close proximity of the surface boundary, the potential for
precipitation will exist across portions of the area each day Sunday
through Wednesday. Temperatures will be closely tied to the position
of the front, with the warmest readings residing across the southern
portions of the CWA.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1239 PM CDT WED APR 10 2013
One band of rain will soon exit west central MO while another area of
rain will spread north-northeast from OK and south central KS and
into all 3 terminals by mid afternoon. Ceilings will be tricky until
this next area of rain moves in. Most likely will see ceilings bounce
between IFR and VFR until the rain returns...then back down to IFR
cigs and MVFR visibilities through the night.
Increasing westerly winds Thursday morning will bring in some drier
air and as the upper system pulls away we should see cigs improve to
MVFR. Scattered wrap around showers should re-visit northwest MO
Thursday morning and could reach as far south as KSTJ.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...FLOOD WATCH until 1 AM CDT Thursday FOR MOZ007-008-015>017-
023>025-031>033-038>040-044>046-054.
&&
$$
SHORT TERM...MJ
LONG TERM...Blair
AVIATION...MJ
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
339 PM CDT WED APR 10 2013
...SEVERE WEATHER POTENTIAL INCREASING ACROSS SOUTH CENTRAL MISSOURI...
.MESOSCALE DISCUSSION...
ISSUED AT 320 PM CDT WED APR 10 2013
THE INITIAL COLD FRONT OR PRE-FRONTAL TROUGH HAD STALLED ACROSS
SOUTH CENTRAL MISSOURI THIS AFTERNOON AND EXTENDED FROM JUST EAST
OF BRANSON TO JUST EAST OF ROLLA. TEMPERATURES HAD RISEN TO NEAR
80 DEGREES ACROSS FAR SOUTH CENTRAL MISSOURI WHILE READINGS WERE
IN THE 40S NEAR THE MISSOURI KANSAS BORDER. PRECIPITATION REMAINED
WIDESPREAD FROM EASTERN OKLAHOMA INTO CENTRAL MISSOURI BEHIND THE
SECONDARY OR TRUE COLD FRONT.
THE ENVIRONMENT ACROSS FAR SOUTH CENTRAL MISSOURI OR GENERALLY
EAST OF A GAINESVILLE TO SALEM LINE CONTINUED TO BECOME MORE FAVORABLE
FOR THE DEVELOPMENT OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EARLY EVENING WITH SCATTERED CONVECTION ALREADY DEVELOPING IN THE
WARM SECTOR.
MIXED LAYER CAPE WAS ON THE ORDER OF 1500-2000 J/KG WITH LOW LEVEL
CAPE DEPICTED BY RUC ANALYSIS BETWEEN 50 AND 100 J/KG. THE 18Z
SOUNDING FROM LITTLE ROCK DEPICTED A SIMILAR ENVIRONMENT.
ENVIRONMENTAL HELICITIES CURRENTLY RANGED UP TO 100 M2/S2 BUT
SURFACE OBSERVATIONS SHOWED BACKING WINDS. ALSO EXPECT DEEP LAYER
SHEAR AND ENVIRONMENTAL HELICITIES TO INCREASE AS THE AFTERNOON
PROGRESSES WITH THE APPROACH OF THE UPPER TROUGH AND A SURFACE
WAVE TRACKING NORTH FROM ARKANSAS.
WITH THAT SAID THE ENVIRONMENT WILL BECOME INCREASINGLY FAVORABLE
FOR SUPERCELL DEVELOPMENT INTO EARLY THIS EVENING. THE OVERALL
RISK FOR SEVERE WEATHER HAS INCREASED INCLUDING THE POTENTIAL FOR
TORNADOES.
OTHERWISE SHOWERS AND EMBEDDED CONVECTION WILL CONTINUE BEHIND
THE FRONT THIS AFTERNOON. THE PERSISTENT RAINFALL AND TRAINING
OF CONVECTION COULD LEAD TO FLOODING ISSUES THIS AFTERNOON INTO
THIS EVENING. A FLOOD WATCH REMAINS IN EFFECT FOR THE ENTIRE
FORECAST AREA INTO THIS EVENING.
EMERGENCY MANAGERS...LOCAL MEDIA...AND SPOTTERS ACROSS SOUTH
CENTRAL MISSOURI SHOULD CLOSELY MONITOR RADAR TRENDS...AND STAYED
TUNED FOR THE ISSUANCE OF WATCHES AND WARNINGS.
&&
.SHORT TERM...(TONIGHT THROUGH THURSDAY)
ISSUED AT 320 PM CDT WED APR 10 2013
SHOWERS AND THUNDERSTORMS WILL OVERSPREAD SOUTH CENTRAL MISSOURI
AND THE EASTERN OZARKS THIS EVENING AS THE DEEP UPPER TROUGH MOVES
SLOWLY EAST. A BROAD DIFFLUENT FLOW AND AN UPPER JET STREAK COMING
ACROSS THE REGION WILL ENHANCE OVERALL SYNOPTIC SCALE LIFT
RESULTING IN WIDESPREAD RAINFALL. GIVEN THE TRAINING NATURE OF THE
PRECIPITATION AND PRECIPITABLE WATER VALUES NEAR 1.25 WILL
SUPPORT MODERATE TO HEAVY RAINFALL AND THE POTENTIAL FOR
FLOODING. A FLOOD WATCH REMAINS IN EFFECT THROUGH MIDNIGHT.
THE POTENTIAL FOR SEVERE WEATHER WILL PERSIST ACROSS THE EASTERN
OZARKS THROUGH EARLY THIS EVENING BEFORE THE SURFACE FRONT MOVES
EAST. THE RAINFALL WILL TAPER OFF FROM THE WEST OVERNIGHT.
THE DEEP UPPER TROUGH WILL MOVE ACROSS THE REGION LATER TONIGHT
AND THURSDAY ALLOWING AN UNSEASONABLY COLD AIRMASS TO OVERSPREAD
THE REGION. LOWS TONIGHT MAY APPROACH THE FREEZING MARK ACROSS FAR
SOUTHEASTERN KANSAS AND EXTREME SOUTHWESTERN MISSOURI BUT
CONDITIONS WILL NOT BE CONDUCIVE TO FROST...AND FREEZING
TEMPERATURES WILL BE SHORT LIVED AROUND SUNRISE. HIGH TEMPERATURES
THURSDAY WILL ONLY REACH THE 40S.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 320 PM CDT WED APR 10 2013
THE COLD WEATHER WILL PERSIST THURSDAY NIGHT INTO FRIDAY NIGHT WITH
LOWS BOTH NIGHTS IN THE LOWER TO MIDDLE 30S AND POSSIBLY UPPER
20S. THERE IS SOME UNCERTAINTY ON THE AMOUNT OF CLOUD COVER WHICH
MAY PREVENT MAXIMIZING RADIATION AL COOLING.
MORE SPRING LIKE WEATHER WILL RETURN OVER THE WEEKEND AS THE FLOW
SHIFTS TO THE SOUTH. A SERIES OF DISTURBANCES RIDING THROUGH A
MORE ZONAL FLOW WILL BRING AN UNSETTLED WEATHER PATTERN NEXT WEEK
WITH PERIODIC CHANCES FOR SHOWERS. HOWEVER CONFIDENCE ON THE
TIMING OF THESE SYSTEMS IS LOW AT THIS TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1218 PM CDT WED APR 10 2013
WIDESPREAD IFR CONDITIONS WILL CONTINUE ACROSS THE REGION THIS
AFTERNOON INTO THE OVERNIGHT HOURS AS A FRONTAL BOUNDARY PUSHES
ACROSS THE AREA. WINDS WILL SHIFT TO WESTERLY THROUGH THE
AFTERNOON. PRECIPITATION WILL CONTINUE THROUGH THE EVENING HOURS
AS THE FRONT PUSHES TO THE EAST. DURING THE AFTERNOON...A FEW
THUNDERSTORMS MAY INTENSIFY WITH INCREASED INSTABILITY. CEILINGS
WILL BEGIN TO LIFT IN THE MORNING AS THE FRONT EXITS TO THE EAST.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR MOZ055>058-066>071-
077>083-088>098-101>106.
KS...FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR KSZ073-097-101.
&&
$$
MESOSCALE...FOSTER/WISE
SHORT TERM...FOSTER
LONG TERM...FOSTER
AVIATION...KARDELL
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
123 PM CDT WED APR 10 2013
...SEVERE WEATHER POTENTIAL INCREASING ACROSS SOUTH CENTRAL MISSOURI...
.MESOSCALE DISCUSSION...
ISSUED AT 115 PM CDT WED APR 10 2013
THE INITIAL COLD FRONT OR PRE-FRONTAL TROUGH HAD STALLED ACROSS
SOUTH CENTRAL MISSOURI AT MIDDAY AND EXTENDED FROM JUST EAST OF
BRANSON TO JUST EAST OF ROLLA. TEMPERATURES HAD RISEN INTO THE MID
AND UPPER 70S ACROSS FAR SOUTH CENTRAL MISSOURI WHILE READINGS
WERE IN THE 40S NEAR THE MISSOURI KANSAS BORDER. PRECIPITATION
REMAINED WIDESPREAD FROM EASTERN OKLAHOMA INTO CENTRAL MISSOURI
BEHIND THE SECONDARY OR TRUE COLD FRONT.
THE ENVIRONMENT ACROSS FAR SOUTH CENTRAL MISSOURI OR GENERALLY
EAST OF A GAINESVILLE TO SALEM LINE HAS BECOME INCREASING
FAVORABLE FOR THE DEVELOPMENT OF SEVERE THUNDERSTORMS THIS
AFTERNOON AND EARLY EVENING.
MIXED LAYER CAPE WAS ON THE ORDER OF 1500 J/KG WITH LOW LEVEL
CAPE DEPICTED BY RUC ANALYSIS BETWEEN 50 AND 100 J/KG. THE 18Z
SOUNDING FROM LITTLE ROCK DEPICTED A SIMILAR ENVIRONMENT.
ENVIRONMENTAL HELICITIES CURRENTLY RANGED UP TO 100 M2/S2 BUT
SURFACE OBSERVATIONS SHOWED BACKING WINDS. ALSO EXPECT DEEP LAYER
SHEAR AND ENVIRONMENTAL HELICITIES TO INCREASE AS THE AFTERNOON
PROGRESSES WITH THE APPROACH OF THE UPPER TROUGH AND A SURFACE
WAVE TRACKING NORTH FROM ARKANSAS.
WITH THAT SAID THE ENVIRONMENT WILL BECOME INCREASINGLY FAVORABLE
FOR SUPERCELL DEVELOPMENT FROM MID AFTERNOON INTO EARLY THIS
EVENING. THE OVERALL RISK FOR SEVERE WEATHER HAS INCREASED
INCLUDING THE POTENTIAL FOR TORNADOES.
OTHERWISE SHOWERS AND EMBEDDED CONVECTION WILL CONTINUE BEHIND
THE FRONT THIS AFTERNOON. THE PERSISTENT RAINFALL AND TRAINING
OF CONVECTION COULD LEAD TO FLOODING ISSUES THIS AFTERNOON INTO
THIS EVENING. A FLOOD WATCH REMAINS IN EFFECT FOR THE ENTIRE
FORECAST AREA INTO THIS EVENING.
EMERGENCY MANAGERS...LOCAL MEDIA...AND SPOTTERS ACROSS SOUTH
CENTRAL MISSOURI SHOULD CLOSELY MONITOR RADAR TRENDS...AND STAYED
TUNED FOR THE ISSUANCE OF WATCHES AND WARNINGS.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 300 AM CDT WED APR 10 2013
WELL WE CERTAINLY HAVE STRUGGLED WITH THE FORECAST OVER THE LAST
24 HOURS. A COLD FRONT HAS SHIFTED EAST INTO THE WESTERN
CWFA...WAY AHEAD OF OUR FORECAST AND GUIDANCE. THE FRONT HAS
UNDERCUT ANY WEAK CONVECTION THAT GETS GOING ALONG IT. DEEPER AND
MORE WIDESPREAD CONVECTION IS OCCURRING BACK OVER EASTERN KS AND
NORTHEAST OK...VERY ELEVATED. THERE IS SOME CONCERN FOR SMALL HAIL
IN THE NEAR TERM AS DIFFLUENT FLOW ALOFT...MUCH OF IT BEHIND THE
COLD FRONT FOR NOW...SHIFTS EAST PROVIDING LARGER SCALE LIFT.
GIVEN THAT GUIDANCE (AND OUR FORECAST) HAS MISSED BY A
CONSIDERABLE AMOUNT AS TO WHERE THE FRONT IS RIGHT NOW LEADS TO A
LOW CONFIDENCE FORECAST IN TERMS OF WHERE HEAVIER RAINFALL AND
SEVERE WEATHER POTENTIAL WILL SET UP LATER TODAY. WILL WATCH THE
PROGRESS OF THE FRONT CLOSELY. IN THEORY...EXPECT THE FRONT TO
SLOW IT`S PROGRESS FOR A TIME IN THE DEEP SSW UPPER LEVEL
FLOW...ALLOWING FOR SOME DESTABILIZATION OVER THE EASTERN CWFA BY
AFTERNOON. FORECAST MODELS SHOW AN INCREASE IN CONVECTION OVER
EASTERN MO THIS AFTERNOON/EARLY EVENING AS A RESULT...BUT I HAVE
ABSOLUTELY NO CONFIDENCE AS TO WHERE THE FRONT WILL SET UP. WILL
KEEP A CONDITIONAL MENTION OF SEVERE WEATHER CHANCES OVER THE
EASTERN CWFA LATER TODAY...ESPECIALLY IF CONVECTION CAN BEGIN TO
DEVELOP WITHIN THE WARM SECTOR. SO FAR THAT HAS BEEN HARD TO DO.
TEMPERATURE TRENDS: COLDER AIR IS ALREADY MOVING INTO THE WESTERN
CWFA...AND WILL JUST TRY TO DO THE BEST I CAN IN TERMS OF PROGGING
SHORT TERM TRENDS. ALREADY HAVE UPPER 40S/NEAR 50 DEGREES OVER OUR
SE KS COUNTIES...AND IT ISN`T LIKELY TO GET ANY WARMER. THE
TEMPERATURE FORECAST MAYBE AS MUCH ART AS IT IS SCIENCE IN THE
NEAR TERM.
HYDROLOGY: AFTER A BIT OF COLLABORATION...HAVE DECIDED NOT TO
ISSUE A FLOOD WATCH FOR LATER TODAY AND TONIGHT. TOO MANY
QUESTIONS EXIST. WILL NEED TO WATCH TRENDS THOUGH WITH THE
POTENTIAL OF HEAVIER RAIN DEVELOPING NEAR AND JUST BEHIND THE
FRONT LATER TODAY/EARLY TONIGHT.
.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 245 AM CDT WED APR 10 2013
NO BIG CHANGES HAVE BEEN MADE TO THE FORECAST FOR THIS PERIOD. A
VERY CHILLY AIR MASS WILL REMAIN OVER THE REGION THROUGH EARLY
SATURDAY WITH A COUPLE OF NIGHTS SEEING TEMPERATURES FALL TO THE
LOW 30S. THIS IS A CONCERN FOR THE EARLY PART OF THE GROWING
SEASON...BUT SO FAR AM NOT SEEING A WIDESPREAD HARD FREEZE. THE
LATEST GFSX MOS HAS COME UP A LITTLE ON LOWS. THE ECMWF HAS SFC
HIGH PRESSURE RIGHT ON TOP OF OUR AREA BY 12Z SAT WITH TEMPS CLOSE
TO FREEZING. FROST HEADLINES SEEM LIKE A GOOD BET AT SOME POINT.
SOUTH WINDS WILL PICK UP LATE SATURDAY AS A STRONG SHORTWAVE AND
SFC LOW MOVE INTO THE NORTHERN AND CENTRAL PLAINS. A COLD FRONT
EVENTUALLY WILL APPROACH AND THEN BECOME STATIONARY OVER THE
REGION AS SW FLOW ALOFT BECOMES ESTABLISHED AS A LONG WAVE TROUGH
DEVELOPS OVER THE WESTERN CONUS. MOISTURE ADVECTION FROM THE SOUTH
WILL INITIALLY BE LIMITED...BUT LIKELY ENOUGH TO HAVE SOME LOW
RAIN CHANCES FOR NOW FOR LATE SUNDAY-TUE.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1218 PM CDT WED APR 10 2013
WIDESPREAD IFR CONDITIONS WILL CONTINUE ACROSS THE REGION THIS
AFTERNOON INTO THE OVERNIGHT HOURS AS A FRONTAL BOUNDARY PUSHES
ACROSS THE AREA. WINDS WILL SHIFT TO WESTERLY THROUGH THE
AFTERNOON. PRECIPITATION WILL CONTINUE THROUGH THE EVENING HOURS
AS THE FRONT PUSHES TO THE EAST. DURING THE AFTERNOON...A FEW
THUNDERSTORMS MAY INTENSIFY WITH INCREASED INSTABILITY. CEILINGS
WILL BEGIN TO LIFT IN THE MORNING AS THE FRONT EXITS TO THE EAST.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR MOZ055>058-066>071-
077>083-088>098-101>106.
KS...FLOOD WATCH UNTIL MIDNIGHT CDT TONIGHT FOR KSZ073-097-101.
&&
$$
MESOSCALE...FOSTER
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...KARDELL
AREA FORECAST DISCUSSION
NWS SPRINGFIELD MO
126 AM CDT WED APR 10 2013
.MESOSCALE DISCUSSION...
ISSUED AT 1256 AM CDT WED APR 10 2013
ROBUST CONVECTION HAS BEEN HARD PRESSED TO DEVELOP DURING THE LATE
EVENING AND EARLY OVERNIGHT HOURS AHEAD OF A SLOWLY APPROACHING
COLD FRONT. AS OF 1 AM...THE COLD FRONT WAS JUST CROSSING THE
KANSAS/MISSOURI STATE LINE. THE FRONT ITSELF HAS MANAGED TO PUSH
UP SOME WEAK CONVECTIVE ELEMENTS OVER THE LAST HOUR NEAR THE STATE
LINE. THE MAJORITY OF CONVECTION UP TO THIS POINT HAS BEEN TIED
CLOSER TO THE 850 MB FRONT. NEEDLESS TO SAY...MODELS HAVE BEEN
HORRENDOUS IN THEIR HANDLING OF THE CAPPING INVERSION/CONVECTIVE
INITIATION OVER THE WARM SECTOR.
FOR THE REMAINDER OF THE OVERNIGHT PERIOD...THE SURFACE FRONT WILL
CONTINUE TO MAKE SLOW PROGRESS TO THE EAST ACROSS WESTERN
MISSOURI. ELEVATED CONVECTION WILL BECOME INCREASINGLY MORE
WIDESPREAD THROUGHOUT THE NIGHT AS HEIGHT FALLS BEGIN TO
OVERSPREAD THE REGION. WE STILL FEEL THERE WILL BE ENOUGH ELEVATED
CAPE TO CARRY A LIMITED HAIL/WIND RISK IN THE HAZARDOUS WEATHER
OUTLOOK. WE WILL ALSO HAVE TO WATCH FOR TRAINING OF THUNDERSTORMS
LATE TONIGHT AROUND THE INTERSTATE 49 CORRIDOR.
PRECIPITATION CHANCES ACROSS THE EASTERN OZARKS ARE A TOUGHER
CALL. THE 00Z NAM IS INSISTENT ON THE CAP ERODING ACROSS THE
EASTERN OZARKS DURING THE PREDAWN HOURS. MEANWHILE THE RAP HOLDS
IT STRONG. WE ARE GOING TO SIDE WITH THE RAP ON THIS ONE...WHICH
PRETTY MUCH ELIMINATES THE POTENTIAL FOR SURFACE BASED CONVECTION
AND AN ATTENDANT SEVERE THREAT ACROSS THE EASTERN OZARKS
OVERNIGHT. INTERESTINGLY...THE RAP DOES WEAKEN INHIBITION FOR
SLIGHTLY ELEVATED PARCELS. THUS...WE DECIDED TO GO WITH ISOLATED
TO SCATTERED SHOWER/THUNDERSTORM COVERAGE ACROSS THE EASTERN
OZARKS DURING THE PREDAWN HOURS.
&&
.SHORT TERM...(WEDNESDAY)
ISSUED AT 244 PM CDT TUE APR 9 2013
THUNDERSTORMS WILL BE ONGOING WEDNESDAY MORNING ACROSS THE
REGION. THE FRONT WILL CONTINUE TO PROGRESS TO THE EAST DURING THE
DAY WEDNESDAY...AND AS INSTABILITY INCREASES AT LEAST A BIT...WE
MAY SEE AN UPTICK IN SEVERE COVERAGE BY AFTERNOON ACROSS THE
EASTERN OZARKS. STILL BELIEVE AT THIS POINT THAT HAIL AND WIND
WILL BE THE PRIMARY THREATS TOMORROW...THOUGH A TORNADO THREAT
COULD MATERIALIZE IF SUFFICIENT INSTABILITY CAN DEVELOP AHEAD OF
THE FRONT. GIVEN WHAT SHOULD BE EXTENSIVE CLOUD COVER AND ONGOING
CONVECTION...THOUGH...I HAVE MY DOUBTS.
HEAVY RAIN WILL CONTINUE TO BE A CONCERN AS WELL ON WEDNESDAY...WITH
THE GFS IN PARTICULAR DEVELOPING A VERY HEAVY AXIS OF QPF ACROSS THE
EASTERN OZARKS. THIS SEEMS A BIT OVERDONE AND MOST LIKELY THE
RESULT OF CONVECTIVE FEEDBACK...BUT A GOOD ONE TO LOCALLY TWO INCHES
OF RAIN SEEMS REASONABLE FOR THIS REGION. SIMILAR TO
TONIGHT...AMOUNTS JUST DON`T LOOK HIGH ENOUGH OVER A SHORT DURATION
TO WARRANT A HYDRO WATCH OF SOME SORT AT THIS TIME.
AGAIN...THOUGH...TRENDS WILL BE MONITORED.
THE OTHER BIG FORECAST CONCERN FOR WEDNESDAY WILL BE THE EFFECTS OF
THE PASSING FRONTAL BOUNDARY ON TEMPERATURES. AS CLEARLY EVIDENCED
OVER KANSAS TODAY...A VERY IMPRESSIVE GRADIENT IN TEMPS IS EXPECTED
ON WEDNESDAY FROM WEST TO EAST WITH THE FRONT BISECTING THE CWA.
FOR AREAS ALONG AND WEST OF U.S. 65...SUSPECT WEDNESDAY`S CALENDAR
DAY HIGH TEMPS WILL BE SET AT OR SHORTLY AFTER MIDNIGHT...WITH
TEMPERATURES RAPIDLY FALLING BEHIND THE FRONT...AND THEN...AT
BEST...HOLDING STEADY WEDNESDAY AFTERNOON. FOR AREAS EAST OF U.S.
65...TEMPERATURES WILL WARM NICELY INTO THE 70S AHEAD OF THE
FRONT...AND THEN FALL RAPIDLY AS THE FRONT PASSES.
PRECIPITATION SHOULD SLOWLY DECREASE IN COVERAGE WITH TIME ON
WEDNESDAY AFTERNOON/EVENING...AS THE FRONT BEGINS TO EXIT THE
EASTERN CWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 244 PM CDT TUE APR 9 2013
LARGE SCALE TROUGH AND CLOSED LOW WILL STILL BE TO THE WEST OF THE
CWA ON WEDNESDAY NIGHT WITH THE SURFACE FRONT JUST ON THE EASTERN
EDGE OF THE CWA. BEST INSTABILITY WILL BE EAST OF THE AREA BY THEN
SO SEVERE THREAT SHOULD HAVE EXITED THE CWA BY 00Z THU. HOWEVER
MUCH OF THE EXPECTED RAINFALL WILL BE POST FRONTAL WITH THIS
SYSTEM AND STILL EXPECT A DECENT AMOUNT OF THE RAINFALL TO OCCUR
WEDNESDAY NIGHT OVER THE EASTERN CWA WHERE 1 TO 2 INCHES COULD
OCCUR. HAVE DECIDED TO HOLD OFF ON ANY FLOOD HEADLINES FOR NOW
WITH BORDERLINE QPF TOTALS EXPECTED.
THE UPPER LEVEL LOW AND TROUGH WILL SHIFT EAST THROUGH THE AREA ON
THURSDAY WITH PRECIPITATION ENDING IN THE EASTERN CWA BY THURSDAY
MORNING. COLD AIR WILL CONTINUE TO ADVECT INTO THE FORECAST AREA
BEHIND THE FRONT AND WILL BRING A TOUCH OF WINTER TIME
TEMPERATURES TO THE AREA FOR A COUPLE OF DAYS. IN FACT...WE MAY
DIP DOWN TO THE FREEZING MARK BOTH FRIDAY MORNING AND SATURDAY
MORNING WITH THE BEST CHANCE FOR FROST ON SATURDAY MORNING AS THE
SURFACE RIDGE PLANTS ITSELF OVERHEAD BY 12Z SAT.
A MORE ZONAL PATTERN SETS UP FOR THE REMAINDER OF THE WEEKEND AND
WE SHOULD SEE A QUICK WARMUP TAKE PLACE AS SOUTHERLY LOW LEVEL
FLOW REDEVELOPS ON THE BACK SIDE OF THE SURFACE RIDGE.
ANOTHER TROUGH WILL BEGIN TO DEVELOP BY THE BEGINNING OF NEXT WEEK
WITH SOUTHWEST FLOW REDEVELOPING ALOFT. A FRONTAL BOUNDARY WILL
TRY TO MAKE IT INTO THE AREA WITH SHOWER/THUNDERSTORM ACTIVITY
LIKELY INCREASING BY MIDWEEK.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1143 PM CDT TUE APR 9 2013
VARIABLY CLOUDY SKIES AND VFR CONDITIONS PREVAILED LATE THIS
EVENING OVER SOUTHWESTERN MISSOURI AIRFIELDS AS A MOIST SOUTHERLY
TROPICAL AIR MASS CONTINUES TO DOMINATE THE AREA. A VERY STRONG
COLD FRONT AHEAD OF A STRONG CANADIAN HIGH PRESSURE SYSTEM IS
SPILLING DOWN THE HIGH PLAINS AND WILL REACH FAR WESTERN MISSOURI
(JLN) ABOUT 0400 LOCAL TIME AND THEN SLOWLY PROGRESS EASTWARD
(TOWARD SGF AND BBG) LATER THIS MORNING. EXPECT VFR CONDITIONS TO
PERSIST UNTIL SOME PRE-FRONTAL SHOWER ACTIVITY BRINGS IN MVFR
CONDITIONS TO THE AREA AROUND 2AM AT JLN AND MORE TOWARD THE LATE
OVERNIGHT/EARLY MORNING HOURS AT SGF AND BBG. WITH FRONTAL PASSAGE
EXPECT A PROLONGED PERIOD OF IFR DUE TO CEILINGS AS MUCH COLDER
BUT STILL VERY MOIST AIR FILTERS INTO THE AREA. IN ADDITION...A
SUBSTANTIAL PART OF THE PRECIPITATION WITH THIS VERY SLOW MOVING
FRONT WILL BE POST-FRONTAL AND STABLE IN NATURE. THUS...DROPPED
THUNDER OUT OF THE FORECAST AFTER FRONTAL PASSAGE BUT KEPT
PRECIPITATION IN THE TAFS LATE IN THE FORECAST VALID TIME WITH
CEILINGS ONLY BEGINNING TO LIFT TOWARD MVFR VALUES AT THE END OF
THE TAF FORECAST PERIOD.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
MESOSCALE...SCHAUMANN
SHORT TERM...BOXELL
LONG TERM...LINDENBERG
AVIATION...COLUCCI
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1202 AM CDT WED APR 10 2013
.UPDATE...
ISSUED AT 745 PM CDT TUE APR 9 2013
00Z SOUNDINGS ARE COMING IN SHOWING A PRETTY ROBUST CAPPING
INVERSION AROUND 700MB. ACARS SOUNDINGS FROM KSTL AND KMCI ALSO
SHOW THIS INVERSION. THE LATEST RUC SOUNDINGS ALSO SHOW THIS
INVERSION...THO NOT TO THE EXTENT IT IS APPEARING IN THE ACTUAL
SOUNDINGS. THAT BEING SAID...THINK WE`RE UNLIKELY TO SEE PRECIP
ANYWHERE IN THE CWFA UNTIL AFTER MIDNIGHT...AND EVEN THEN IT MAY
BE DIFFICULT GIVEN THE STRENGTH OF THE INVERSION. HAVE PULLED ALL
POPS BEFORE 06Z FOR THIS REASON. HOWEVER...THE UPPER LEVEL RIDGE
AXIS SHOULD BE WELL EAST OF THE REGION BY 06Z-09Z...AND WITH AN
INCREASING LOW LEVEL JET AHEAD OF THE STORM SYSTEM I KEPT POPS
AROUND WHAT THE DAYSHIFT HAD AFTER 09Z. STILL CAN`T RULE OUT SOME
LATE-NIGHT HAIL OR WIND IN NORTHEAST MO/WEST CENTRAL IL...BUT IT
DOES LOOK A BIT LESS LIKELY THAN IT HAD EARLIER.
CARNEY
&&
.SHORT TERM...(TONIGHT)
ISSUED AT 324 PM CDT TUE APR 9 2013
ALL SYSTEMS ARE ON TRACK FOR A VERY ACTIVE PERIOD OF CONVECTION
AND POTENTIALLY HEAVY RAINFALL GETTING UNDERWAY LATER TONIGHT.
WEAK INSTABILITY IS PRESENT ACROSS THE REGION AT THIS TIME BUT THE
ATMOSPHERE IS LARGELY CAPPED DUE TO A STOUT EML. THE THREAT OF
THUNDERSTORMS IS EXPECTED TO RAMP UP BEGINNING LATE THIS EVENING
AND MORE LIKELY OVERNIGHT AS THE COLD FRONT AND SURFACE LOW MOVE
THROUGH WESTERN MISSOURI AND THE MORE WSW-ENE ORIENTED BOUNDARY
EMANATING FROM THE LOW SINKS INTO NRN MO AND WEST CENTRAL IL. A
COPIOUS FEED OF LOW LEVEL MOISTURE VIA A STOUT SSWLY LLJ WILL
RESULT IN THE STRONGEST FORCING ACROSS THE NRN THIRD OF THE CWA AND
THIS IS WHERE THE HIGHEST PROBABILITY OF CONVECTION WILL RESIDE
ALONG AND AHEAD OF THE SAGGING NORTHERN FRONT. DEEP LAYER SHEAR
AND AMPLE INSTABILITY WILL CONTINUE TO SUPPORT A SEVERE THREAT IN
THE CORRIDOR FROM CENTRAL INTO NE MO.
GLASS
.LONG TERM...(WEDNESDAY THROUGH NEXT TUESDAY)
ISSUED AT 324 PM CDT TUE APR 9 2013
WEDNESDAY AND WEDNESDAY EVENING CONTINUE TO LOOK LIKE THE MAIN SHOW.
THE SURFACE LOW AND TRAILING COLD FRONT WILL TRACK ONLY SLOWLY
EASTWARD ACROSS THE CWA AS THE DEEP PLAINS UPPER TROF BECOMES MORE
NUETRALLY TILTED AND THE FLOW ALOFT BACKS. THIS WILL ALSO RESULT
IN PRECIPITATION DISTRIBUTION SYMBOLIC OF AN ANAFRONT WITH STRONG
LARGE SCALE ASCENT CONTRIBUTING TO SHOWERS AND THUNDERSTORMS WELL
WITHIN THE COOL AIR IN THE WAKE OF THE SURFACE COLD FRONT AS THE
DAY PROGRESSES. THUNDERSTORMS ARE ALSO EXPECTED ALONG AND IMMEDIATELY
AHEAD OF THE COLD FRONT AND ANY MESOSCALE BOUNDARIES. WEAK TO
MODERATELY UNSTABLE CONDITIONS ALONG WITH STRONG DEEP LAYER SHEAR
WILL SUPPORT A SEVERE THUNDERSTORM THREAT JUST ABOUT ANYTIME
DURING THE DAY...HOWEVER CURRENT THOUGHTS ARE THE SEVERE POTENTIAL
SHOULD MAXIMIZE IN THE LATER PART OF THE AFTERNOON AND EVENING
FROM EAST CENTRAL AND SE MO INTO SW IL WHERE THE GREATEST HEATING
AND INSTABILITY SHOULD BE REALIZED AHEAD OF THE ADVANCING COLD
FRONT. I THINK THE DOMINATE MODE WILL BE LINEAR STORM MODES ALTHO
THERE COULD INITIALLY BE A FEW SEMI-DISCRETE STORMS. THE FRONT IS
EXPECTED TO TRACK FROM EASTERN MO IN THE LATE AFTERNOON INTO THE
EASTERN CWA IN ILLINOIS BY LATE EVENING...EXITING THE CWA SHORTLY
OVERNIGHT. MUCH OF THE AREA WILL SEE ANYWHERE FROM 1.5 TO 2.5
INCHES OF RAINFALL WITH THE HIGHEST AMOUNTS IN THE LATE AFTERNOON
AND EVENING ACROSS EAST CENTRAL/SE MO INTO SW IL WHERE THE
STRONGER CONVECTION IS EXPECTED. A FLOOD POTENTIAL OUTLOOK HAS
BEEN ISSUED AND FLOOD OR FLASH FLOOD WATCHES MAY ULTIMATELY BE
NEEDED. SEE THE HYDRO PORTION OF THIS AFD.
MUCH COOLER WEATHER IS EXPECTED THURSDAY INTO FRIDAY WITH WELL
BELOW NORMAL TEMPERATURES. EXTENSIVE CLOUDINESS IS EXPECTED ALONG
WITH GUSTY WEST WINDS ON THURSDAY WITH SOME SCATTERED INSTABILITY
SHOWERS POSSIBLE ACROSS THE NRN CWA. CLOUDS WILL SLOWLY DECREASE/
CLEAR ON FRIDAY AS HIGH PRESSURE BEGINS TO BUILD IN FROM THE WEST.
THE HIGH WILL BE CENTERED OVER THE AREA ON SATURDAY MORNING
LEADING TO A CHILLY START...BUT TEMPS SHOULD BEGIN A MODERATION AS
THE HIGH RETREATS EASTWARD DURING THE AFTERNOON. SOUTHERLY FLOW
AND RISING HEIGHTS SIGNAL A GOOD WARM-UP ON SUNDAY...THEN A WET
PATTERN LOOKS TO SET UP AS WE HEAD INTO THE FIRST PART OF NEXT
WEEK WITH A QUASI-STATIONARY BOUNDARY ACROSS THE REGION AND WSW
FLOW ALOFT.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 1151 PM CDT TUE APR 9 2013
TIMING OF ONSET OF SHRA/TSRA CONTINUES TO BE THE PRIMARY CONCERN
THIS TAF PACKAGE. CURRENTLY...ALL OF THE PRECIPITATION REMAINS
WELL WEST OF THE TERMINALS...THOUGH A LINE OF STORMS HAS INITIATED
ROUGHLY ALONG A KTNU...KCDJ...KLRY LINE...AND IS VERY SLOWLY
DRIFTING EASTWARD. GIVEN HOW SLOWLY THE PRECIPITATION IS
EVOLVING...HAVE SLOWED DOWN THE ONSET OF PCPN AT ALL TAF
SITES...EXPECTING 09/10Z FOR KUIN AND KCOU...AND AROUND 14Z FOR
METRO TAF SITES. THERE SHOULD BE A LULL BEHIND THE FIRST LINE OF
STORMS PRIOR TO THE SECOND...MORE POTENT...ROUND IN THE LATE
AFTERNOON AND EVENING. CURRENTLY EXPECT SOUTHERLY/SOUTHEASTERLY
FLOW TO PERSIST UNTIL WEDNESDAY AFTERNOON...WHEN WINDS WILL VEER
TO THE WEST AND EVENTUALLY NORTHWEST BY THE END OF THE TAF PERIOD
WITH FROPA. VFR CONDITIONS WILL CONTINUE TONIGHT...THOUGH ONCE
PRECIPITATION BEGINS...EXPECT A DETERIORATION TO MVFR...AND
POTENTIALLY IFR WITH SOME OF THE STRONGER STORMS.
SPECIFICS FOR KSTL...A LINE OF STORMS CURRENTLY EXTENDING OVER
WESTERN MISSOURI WILL SLOWLY DRIFT EASTWARD...IMPACTING THE
TERMINAL AROUND 14Z. VFR CONDITIONS ARE EXPECTED THROUGH THE
OVERNIGHT HOURS...THOUGH MVFR AND POSSIBLY IFR CONDITIONS CAN BE
EXPECTED WITH SHRA/TSRA THAT MOVES OVER THE TERMINAL. A LULL IN
ACTIVITY IS ANTICIPATED DURING THE LATE MORNING AND EARLY
AFTERNOON HOURS WEDNESDAY...PRIOR TO THE SECOND ROUND OF STORMS
MOVING THROUGH DURING THE EVENING HOURS. FLOW TONIGHT WILL REMAIN
SOUTHERLY TO SOUTHEASTERLY...VEERING TO THE WEST AND EVENTUALLY
NORTHWEST LATE IN THE TAF PERIOD AS A COLD FRONT MOVES THROUGH.
JP
&&
.HYDROLOGY...
ISSUED AT 215 PM CDT TUE APR 9 2013
MODELS HAVE CONSISTENTLY BEEN GENERATING BETWEEN 1-3
INCHES OF QPF ACFOSS THE ST. LOUIS SERVICE AREA OVER THE NEXT 48
HOURS. BASED ON THIS...CONTINGENCY FORECASTS ARE TAKING AREA RIVERS
TO NEAR FLOOD STAGE...GENERATING MINOR FLOODING FOR MOST AREA
TRIBUTARIES.
THIS WILL LIKELY AFFECT THE AREA PROGRESSIVELY FROM NORTH TO SOUTH.
THE INITIAL RAINFALL WILL AFFECT PRIMARILY NORTHEASTERN MISSOURI AND
WEST CENTRAL ILLINOIS TONIGHT AND WEDNESDAY MORNING...WITH RAINFALL
AMOUNTS BETWEEN 1 AND 2 INCHES. THIS WILL LIKELY GENERATE MINOR
FLOODING ALONG SOME NORTHERN STREAMS SUCH AS THE FABIUS RIVER AND
SALT RIVER TRIBUTARIES...THE NORTH RIVER...THE CUIVRE RIVER...AND
THE LA MOINE RIVER. THE THUNDERSTORMS AND RAINFALL WILL GENERATE UP
TO TWO INCHES OR MORE OVER SOUTH CENTRAL AND SOUTHEASTERN MISSOURI
WEDNESDAY AFTERNOON AND NIGHT. THIS WILL LIKELY GENERATE MINOR
FLOODING FOR NUMEROUS SOUTHERN STREAMS...INCLUDING THE MERAMEC
RIVER...THE BOURBEUSE RIVER...THE BIG RIVER...THE BLACK RIVER...AND
THE KASKASKIA RIVER.
THIS WILL ALSO RAISE LEVELS ALONG THE AREA`S MAJOR RIVERS. THE
MISSOURI IS NOT CURRENTLY FORECAST TO FLOOD...BUT LEVELS SHOULD
APPROACH FLOOD STAGE AT HERMANN...CHAMOIS...AND JEFFERSON CITY. ON
THE ILLINOIS RIVER...MINOR FLOODING IS LIKELY NEXT WEEK. ON THE
MISSISSIPPI RIVER...MINOR FLOODING IS ALSO LIKELY ABOVE ALTON AND AT
CHESTER.
WITH ALL OF THESE CONTINGENCY FORECASTS...LEVELS COULD BE
SIGNIFICANTLY LOWER OR HIGHER...DEPENDING ON THE VARIATION OF HEAVY
RAIN AMOUNTS ACROSS THE AREA. THERE IS A POTENTIAL OF
SIGNIFICANT...MODERATE OR GREATER...FLOODING ALONG AREA STREAMS WITH
THIS EVENT. KEEP IN MIND CONTINGENCY FORECASTS ARE NOT OFFICIAL.
OFFICIAL FORECASTS TYPICALLY USE ONLY 24 HOURS OF FORECAST
RAINFALL. CONTINGENCY FORECASTS USE UP TO THREE DAYS OF FORECAST
RAINFALL...SOMETIMES MORE.
FUCHS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
737 PM EDT THU APR 11 2013
.SYNOPSIS...
LOW PRESSURE WILL TRACK ALONG A COLD FRONT AS IT MOVES ACROSS THE
REGION TONIGHT. HIGH PRESSURE WILL SLOWLY BUILD IN THROUGH FRIDAY
INTO THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
SHOWERS CONTINUE TO WORK ACROSS THE AREA. SOME STRONGER ECHOES AND
ISOLATED THUNDER ARE NOTED ALONG THE LEADING EDGE OF THIS. EXPECT
PRECIPITATION TO CONTINUE TO SPREAD NORTH NORTHEAST. IT IS LOOKING
MORE LIKELY THAT MODERATE TO HEAVY RAIN WILL BE PRIMARILY IN THE
EASTERN PART OF THE FORECAST AREA. THIS SHOULD REMAIN SOUTH AND
EAST OF AREAS HEAVILY IMPACTED YESTERDAY. HOWEVER LONGER DURATION
LIGHT RAINFALL WILL CONTINUE IN THE FLOOD WATCH AREA. AND WITH
SATURATED SOILS THERE IS STILL THE POTENTIAL FOR SOME FURTHER
MINOR FLOODING.
22Z RAP SUGGESTS THAT THERE COULD BE A BREAK IN THE PRECIPITATION
ACROSS THE WESTERN SECTIONS LATE THIS EVENING. BUT AS A SHORT WAVE
ROTATES AROUND THE UPPER LOW ADDITIONAL LIGHT SHOWERS COULD
REDEVELOP AND MOVE ACROSS THE FORECAST AREA LATE TONIGHT. THIS
SOLUTION SEEMS PLAUSIBLE BASED ON LATEST TRENDS.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL START TO BUILD IN FROM THE SOUTHWEST ON FRIDAY.
THE HIGH WILL EVENTUALLY BE ABLE TO SPREAD ACROSS THE REGION BY
SATURDAY AFTERNOON/EVENING. HOWEVER AN UPPER LOW WILL REMAIN
ACROSS THE GREAT LAKES. AND DISTURBANCES MOVING THROUGH THE FAST
FLOW ON THE SOUTH SIDE OF THIS SYSTEM COULD TRIGGER A FEW SHOWERS
MAINLY ACROSS THE NORTH. IN ADDITION COOLER TEMPERATURES ALOFT
ALONG WITH LINGERING LOW LEVEL MOISTURE SHOULD RESULT IN QUITE A
BIT OF CLOUD COVER...ESPECIALLY DURING THE DAY TIME PERIODS...AT
LEAST UNTIL THE CENTER OF THE HIGH MOVES IN. TEMPERATURES WILL
FALL BACK BELOW NORMAL. APPEARS THAT SATURDAY COULD BE A BIT
COOLER THAN FRIDAY.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
UNCERTAINTY OF FRONTAL POSITION AND ASSOCIATED PRECIPITATION AND
TEMPERATURES PROVIDE BELOW AVERAGE CONFIDENCE IN THIS FORECAST.
EXPECT DRY WEATHER ON SUNDAY WITH HIGH PRESSURE RETREATING EAST. DRY
CONDITIONS ARE PROBABLE FOR MONDAY AS WELL SINCE LATEST RUNS OF
ECMWF AND GFS HAVE SHOWERS ASSOCIATED WITH THE FRONT STAYING TO THE
NORTHWEST.
PATTERN CHANGE IS INDICATED FOR TUESDAY WHEN THE FRONTAL ZONE IS
FORECAST TO DROP INTO CENTRAL OHIO. THERE WILL BE A CHANCE OF
SHOWERS AND THUNDERSTORMS IN THE MARGINALLY UNSTABLE AIR MASS ALONG
AND AHEAD OF THE FRONT.
MODEL SOLUTIONS DIVERGE FOR WEDNESDAY...WITH ECMWF DRY AND THE GFS
WET. WENT WITH A MODEL BLEND GIVING A CHANCE OF SHOWERS.
THUNDERSTORMS WILL POSSIBLE ON THURSDAY IN A MORE UNSTABLE PATTERN
AHEAD OF A STRONG COLD FRONT.
CURRENT INDICATIONS ARE THAT TEMPERATURES WILL BE ABOVE NORMAL
THROUGH THE PERIOD...WITH HIGHS IN THE 60S AND 70S.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
HEAVIER/STEADIER RAINS NOW SPREADING OVER THE AREA AS COLD FRONT
TO THE WEST INCHES CLOSE. EXPECT WIDESPREAD MVFR VSBYS IN RAIN
THIS EVENING WITH OCCASIONAL CONVECTIVE ELEMENTS DROPPING
CONDITIONS TO IFR. REMOVED THREAT OF THUNDER...RECENT COUPLE OF
HOURS LIGHTNING TRENDS KEEPING MOST/ALL LIGHTNING SOUTH OF CENTRAL
KY...AND REALLY NO CHANGES TO INSTBY EXPECTED. THERE MAY BE A
RUMBLE HERE AND THERE BUT NOT WORTH INSERTING IN TAFS ANYMORE.
WINDS ARE REALLY ALL OVER THE PLACE RIGHT NOW WITH LOW PRESSURE
JUST TO THE WEST AND THE MYRIAD OF SURFACE BOUNDARIES. IN GENERAL
FLOW WILL BE LIGHT THROUGH 04Z AND THEN BEGIN TO PICK UP OUT OF
THE WSW WITH THE PASSAGE OF THE COLD FRONT WITH SOME GUSTS TO
20KTS DURING THE OVERNIGHT. THOSE GUSTY WSW WINDS CONTINUE THROUGH
MUCH OF FRIDAY WITH CONTINUED MVFR CIGS...THAT WILL BEGRUDGINGLY
LIFT TO VFR BY THE END OF THE DAY AND DRIER AIR WORKS IN. UNTIL
THEN...EXPECT THE BIGGEST IMPACTS TO AVIATION TO BE BETWEEN 00Z
AND 05Z WITH RAIN/LOW CIGS AND VSBYS...AND FROM 05Z TO 10Z WITH
LOW CIGS IN THE WAKE OF THE COLD FRONT.
OUTLOOK...NO SIGNIFICANT WEATHER EXPECTED.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...FLOOD WATCH THROUGH FRIDAY MORNING FOR OHZ026-034-035-042>046.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...CONIGLIO
AVIATION...BINAU
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1056 AM EDT WED APR 10 2013
.SYNOPSIS...
AN EAST TO WEST STATIONARY FRONT REMAINS JUST TO OUR NORTH THROUGH
TODAY...KEEPING US IN THE WARM SECTOR. A STRONG COLD FRONT MAY
BRING A SEVERE THUNDERSTORM THREAT LATE THURSDAY INTO THURSDAY
NIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
...MORNING UPDATE...
BUMPED UP TEMPERATURES...ESPECIALLY IN THE WV COAL FIELDS WHERE
ABUNDANT SUNSHINE HAS LED TO STRONG TEMPERATURE RISES ALREADY.
ALSO INCREASED POPS TODAY ACROSS OUR SE OHIO COUNTIES WITH THE
EROSION OF THE CAP BECOMING MORE EVIDENT IN THE LATEST RUNS OF
NAM/NMM AND HRRR SUGGESTING CONVECTION DEVELOPING IN THOSE COUNTIES.
...PREVIOUS DISCUSSION...
WARM SECTOR MODE THROUGH THE PERIOD. VARIOUS MODELS DO SHOW WEAK
RIPPLES WITH PRECIPITATION SUGGESTED BUT THESE HAVE TENDED NOT TO
PAN OUT NOW THAT E-W FRONT IS WELL N AND WARM SECTOR HAS CLEANED OUT
A BIT. EVEN CLOUD AMOUNT OUTPUT FROM MODELS IS TOO HIGH IN THIS
MORE SUMMER-LIKE AIR MASS.
INCREASED THUNDERSTORM ACTIVITY IN THE AFTERNOON HEATING MAY GET
CLOSE TO NORTHERN EDGE OF FCST AREA AS WAVE COMING ESE FROM THE
MIDWEST PUSHES FRONT A LITTLE SWD...HAVE SMALL CHANCE THERE THIS
AFTERNOON INTO THIS EVENING. GFS AND ECMWF PUSH THE FRONT FARTHEST
S THIS AFTERNOON AND EVENING. THE WAVE MAY REFLECT CONVECTIVE
FEEDBACK...ITS EFFECTS HAVING MIXED SUPPORT FROM THE LOCAL NEAR
TERM MODELS. STRONG UNIDIRECTIONAL WIND FLOW COUPLED WITH UPWARDS
OF A GRAND OF CAPE COULD RESULT IN VERY STRONG WIND GUSTS AS
REFLECTED VIA SPC SLIGHT RISK ACROSS OUR FAR N...AND INCLUDED STRONG
WIND GUSTS IN FCST.
OTHERWISE EXPECT UPPER LEVEL RIDGING TO HOLD THROUGH MOST OF THE
PERIOD BEFORE STARTING TO SHIFT E LATE...ALLOWING HEIGHTS TO START
TO FALL.
BLENDED IN ADJMET/ADJMAV COMBO FOR HIGHS...LOWS AND DEW POINTS...NO
CHANGES OF IMPORT SAVE FOR LOWER DEW POINTS. THIS RESULTS IN RH
VALUES DOWN AROUND 30 CENTRAL WV THIS AFTERNOON. WE SET A RECORD AT
EKN TUE AND FCST TODAY IS CLOSE IN SEVERAL LOCATIONS...WITH 4 OUT OF
5 CLIMATE SITES SETTING THESE RECORD HIGHS JUST 2 YEARS AGO:
FCST TODAY RECORD YEAR
BKW 80 81 2011 AND PREVIOUS YEAR/S/
CRW 86 89 1933 AND PREVIOUS YEAR/S/
EKN 81 83 2011
HTS 85 87 2011
PKB 84 85 2011
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
CLOUDS...SHOWERS AND STORMS EXPECTED TO DEVELOP AHEAD OF D FIRST
SPRING SEASON STRONG COLD FRONT APPROACHING FROM THE WEST THURSDAY
AFTERNOON. MODELS SHOW PERSISTENT DEEP LOW LEVEL SOUTH SOUTHEASTERLY
FLOW...INCREASING MOISTURE THURSDAY. THE NAM...PREFERRED FOR THE
DEWPOINTS FIELD...SUGGEST DEWPOINTS REACHING THE LOWER 60S ALONG THE
FRONT BY LATE THURSDAY AFTERNOON AND EVENING. THE SREF/GFS SUGGEST
HIGH LIKELY POPS OVER SOUTHEAST OH BY 21Z THU. THE ECMWF AND CMC ARE
SLOWER IN THE QPF FIELDS...BRINGING CONVECTION OVER SOUTHEAST OH BY
OR AFTER 00Z FRIDAY.
AGREE WITH THE TIMING OF THE ACTUAL COLD FRONT WIND SHIFT REACHING
SOUTHEAST OH BY OR AFTER 00Z FRIDAY...BUT WITH DEWPOINTS ON THE
60S...BELIEVE NAM IS MORE REPRESENTATIVE ON ITS SFC CAPE FIELD
INCREASING TO 800 J/KG BY 18Z...AND TO 1000 J/KG BY 21Z THURSDAY.
DEEP LAYER SHEAR INCREASING FROM 35 TO 50 KNOTS FROM 21Z THU TO 03Z
FRI...PW ABOUT 1.25 INCHES...AND SOME BOUNDARY LAYER
CONVERGENCE...PERHAPS TRIGGERED BY DIFFERENTIAL HEATING AND
OROGRAPHIC HEAT SOURCES PROVIDE A GOOD RECIPE FOR CONVECTIVE
INITIATION DURING THE AFTERNOON AND EVENING HOURS. SOME UPPER LEVEL
DIVERGENCE...SUGGESTED BY THE GFS...COULD PROVIDE SOME VENTILATION
FOR STORM TO GROW AND REACH SEVERE CRITERIA. IN FACT...THE SLIGHT
RISK FOR SEVERE WEATHER HAS BEEN EXPANDED TO COVER ROUGHLY THE
WESTERN HALF OF WV...TO INCLUDE SOUTHEAST OH...AND NORTHEAST KY.
THE MAINLY THREAT FOR AFTERNOON AND EVENING STORMS WOULD BE STRONG
DOWNBURST AS FREEZING LEVEL IN THE WARM SECTOR WILL BE AROUND 11-12
KFT. STRONGEST FORCING STACK WITH HEIGHT SEEMS TO BE ALONG THE COLD
FRONT TO REACH SOUTHEAST OH BY OR AFTER 00Z FRIDAY. A SHARP
TEMPERATURE GRADIENT BEHIND AND ALONG THE FRONT...AND ANY DELAYS IN
THE ONSET OF THE COLD FRONT WILL BE PROVIDE LOWER FREEZING
LEVELS...FAVORING SEVERE HAIL AFTER 03Z FRIDAY IF ANY CONVECTION
SURVIVE.
KEPT THE FRONT GENERALLY EXITING THE EASTERN MOUNTAINS 09Z
FRIDAY...WITH SOME LINGERING SHOWERS INTO FRIDAY MORNING.
COOLER AIRMASS DROPS IN BEHIND THE FRONT WHICH WILL LIKELY DROP THE
TEMPERATURES BACK SLIGHTLY BELOW NORMAL THROUGH THE END OF THE WEEK.
PREVIOUS FORECAST TEMPERATURES LOOK ON TRACK. MINOR TWEAKS MADE
THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
COLD FRONT TO THE EAST OF THE CWA AT THE BEGINNING OF THE
PERIOD...WITH A FEW NW UPSLOPE SHOWERS BEHIND THE FRONT FOR FRIDAY
NIGHT INTO SATURDAY. COULD EVEN BE SOME SNOWFLAKES ACROSS THE HIGHER
TERRAIN...AS MUCH COLDER AIR...-2 TO -4 C...RUSHES IN BEHIND THE
FRONT. HIGH PRESSURE WILL BUILD IN FOR MUCH OF THE WEEKEND...FOR
DRIER...BUT COOLER WEATHER. THINGS WILL WARM UP AGAIN BY EARLY NEXT
WEEK AS YET ANOTHER LOW PRESSURE SYSTEM APPROACHES THE
REGION...SPREADING SHOWERS AND THUNDERSTORMS BACK INTO THE PICTURE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
SW FLOW OF WARM AIR SPELLS VFR FCST IN THE WARM SECTOR. PATCHY
ALTOCU EARLY THIS MORNING AND TONIGHT...CU THIS AFTERNOON. THE ONLY
FLY IN THE OINTMENT IS THAT STRONG THUNDERSTORMS IN THE UPPER OHIO
VALLEY LATE THIS AFTERNOON AND THIS EVENING MAY GET AS FAR S AS PKB
AND CKB.
LIGHT TO MODERATE SW FLOW ALOFT BECOMES W LATER THIS MORNING AND
THEN SW AGAIN THIS AFTERNOON. LIGHT SW SFC FLOW EARLY THIS MORNING
WILL BECOME A BIT GUSTY FOR THIS AFTERNOON...BEFORE DIMINISHING
AGAIN TONIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z THURSDAY...
FORECAST CONFIDENCE...HIGH.
ALTERNATE SCENARIOS: SHOWERS AND POSSIBLE THUNDERSTORMS OVER THE
UPPER OHIO VALLEY MAY BRING AVIATION RESTRICTIONS AND GUSTY WINDS TO
PKB AND CKB LATE TODAY AND THIS EVENING.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01
EDT 1HRLY 10 11 12 13 14 15 16 17 18 19 20 21
CRW CONSISTENCY H H H H H H H H H H H H
HTS CONSISTENCY H H H H H H H H H H H H
BKW CONSISTENCY H H H H H H H H H H H H
EKN CONSISTENCY H H H H H H H H H H H H
PKB CONSISTENCY H H H H H H H H H H H H
CKB CONSISTENCY H H H H H H H H H H H H
AFTER 12Z THURSDAY...
IFR POSSIBLE IN SHOWERS AND THUNDERSTORMS THURSDAY INTO FRIDAY AHEAD
OF...AND ALONG A STRONG FRONT.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/JMV/SL/26
NEAR TERM...TRM/TAX
SHORT TERM...ARJ
LONG TERM...SL
AVIATION...TRM/TAX
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
200 AM EDT WED APR 10 2013
.SYNOPSIS...
A WARM FRONT ACROSS NORTHERN OHIO AND NORTHWEST PENNSYLVANIA WILL
MOVE NORTH TONIGHT AND THEN MOVE SOUTH BY LATE TONIGHT. THE FRONT
WILL THEN REMAIN IN THE AREA THROUGH THURSDAY BEFORE EVENTUALLY
MOVING SOUTH FRIDAY BEHIND A STRONGER AREA OF LOW PRESSURE.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FORECAST UPDATE IS OUT WITH LOWER POPS FOR THE OVERNIGHT PERIOD.
SHOWERS WILL CONTINUE TO CLIP ERIE PA FOR A FEW MORE HOURS BEFORE
SHIFTING EAST. A FAIR AMOUNT OF SUBSIDENCE IS OBSERVED BEHIND THE
COMPLEX THAT MOVED ACROSS LOWER MICHIGAN THIS AFTERNOON. A FEW
ADDITIONAL THUNDERSTORMS ARE STARTING TO DEVELOP WESTWARD FROM
MICHIGAN TO WISCONSIN ALONG THE 850MB FRONT WITH NOTHING SHOWING
UP ON REGIONAL RADARS TO OUR SOUTH. IN FACT...SKIES HAVE CLEARED ACROSS
SOUTHERN PORTIONS OF THE FORECAST AREA AND THE RUC IS SHOWING
1000-500MB RH DECREASING OVER THE FORECAST AREA FROM THE SOUTH BETWEEN
06-12Z. THE NEW 00Z NAM HAS ALSO BACKED OFF ON QPF PRIOR TO 12Z
SO HAVE DROPPED ALL AREAS DOWN TO JUST A CHANCE OVERNIGHT. STILL
EXPECTING BETTER CHANCES OF SHOWERS AND THUNDERSTORMS TO FILL IN
ALONG THE BOUNDARY ON WEDNESDAY.
COLD FRONT IS HOVERING FROM NEAR BOWLING GREEN TO CLEVELAND TO
ASHTABULA WITH A 20 DEGREE VARIATION ON EITHER SIDE. NOT EXPECTING
IT TO PUSH MUCH FURTHER SOUTH OVERNIGHT...ESPECIALLY WITH LOWER
CHANCES OF PRECIPITATION AND HAVE RAISED MINS ACROSS OUR SOUTHERN
COUNTIES.
PREVIOUS DISCUSSION...THE WARM FRONT IS ACROSS EXTREME NORTHERN OHIO AND
NORTHWEST PA. AN IMPULSE MOVING ALONG THE FRONT AND A LOW LEVEL
JET WILL CAUSE SOME SHOWERS AND THUNDERSTORMS TO DEVELOP THROUGH
THE EVENING. THE BEST CHANCE WILL BE NEAR AND JUST NORTH OF THE
FRONT. WITH THE LOCATION OF THE LOW LEVEL JET WENT WITH HIGH POPS
OVER EXTREME NE OH AND NW PA AND SCATTERED NEAR LAKE ERIE. THE
BEST CHANCE MAY BE THIS EVENING. STILL A THREAT OF SEVERE
THUNDERSTORMS...NO MENTION AS CONFIDENCE IS LOW. LOW TEMPERATURES
ARE TOUGH NEAR THE LAKE BUT AS THE WINDS BECOME SOUTH THEY WILL
MODERATE.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY NIGHT/...
WE WILL HAVE SHOWERS AND THUNDERSTORMS BUT THE TIMING IS STILL IN
QUESTION. DIDN`T PUT IN TOO MUCH RESOLUTION AS CONFIDENCE IS LOW.
WAVES WILL MOVE ALONG THE FRONT AND THAT WILL ENHANCE THE SHOWERS
AND THUNDERSTORMS. THE FARTHER SOUTH THE FRONT GET THE AREAS NORTH
OF IT WILL GET MORE RAIN. SEE THE HYDRO DISCUSSION FOR DETAILS
ABOUT THE FLOODING THREAT. WITH THE BOUNDARY IN THE AREA WE HAVE A
RISK OF SEVERE WEATHER AT TIMES. THE THREAT OF RAIN WILL BEGIN
TO DECREASE FRIDAY AS THE LOW MOVES EAST.
TEMPERATURE FORECAST IS TOUGH ESPECIALLY ON THURSDAY AS THE
BOUNDARY MAY BE SAGGING SOUTH.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
AN UPPER LEVEL TROUGH WILL MOVE EAST OVER THE AREA ON SATURDAY AS
HIGH PRESSURE BUILDS IN AT THE SURFACE. SHOWERS MAY LINGER INTO
SATURDAY ACROSS EXTREME NORTHEAST OHIO AND NORTHWEST PENNSYLVANIA
WITH WESTERLY FLOW BEHIND THE TROUGH. OTHERWISE...DRY CONDITIONS ARE
EXPECTED. THE NEXT LOW PRESSURE SYSTEM WILL BEGIN TO AFFECT THE AREA
LATE SUNDAY AS A WARM FRONT LIFTS NORTH ACROSS THE AREA. AT THIS
POINT NOT EXPECTING MUCH PRECIPITATION WITH THE WARM FRONT AND ANY
PRECIPITATION THAT DOES OCCUR WILL BE MAINLY CONFINED TO THE
LAKE SHORE. A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA MONDAY INTO
TUESDAY AND WILL LIKELY BRING WIDESPREAD SHOWERS ACROSS THE AREA.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
THE FRONT IS NEAR THE SOUTH SHORE OF LAKE ERIE AND MAY WAVER SOME
EARLY THIS MORNING AS A WEAK WAVE OF SHOWERS PASSES THROUGH. I
THINK THE FRONT WILL STAY SOUTH OF KTOL AND THE WIND WILL STAY
FROM THE NORTHEAST AND WILL BECOME NORTHEAST AT KERI EARLY THIS
MORNING AND IFR STRATUS CEILINGS WILL SNEAK IN TO STAY TODAY.
INLAND IT SHOULD REMAIN VFR AND THERE COULD BE A LULL IN THE
SHOWERS FOR A WHILE FROM MID MORNING INTO EARLY AFTERNOON...THEN
THE NEXT WAVE OF SHOWERS AND THUNDERSTORMS WILL MOVE ACROSS THE
AREA MID TO LATE AFTERNOON. CEILINGS AND VISIBILITIES WILL LIKELY
DROP TO MVFR AND EVENTUALLY IFR BY LATE AFTERNOON/EVENING AND
REMAIN SO TONIGHT AS THE FRONT WILL STAY SOUTH OF THE AREA.
.OUTLOOK...NON-VFR CONTINUING INTO SATURDAY.
&&
.MARINE...
A FRONT SHOULD STAY NEAR THE SOUTH SHORE OF LAKE ERIE TONIGHT THEN
DRIFT SLOWLY SOUTH WED SO MAINLY NE WINDS SHOULD PREVAIL OVER THE
LAKE WHILE INCREASING TO ABOUT 10 TO 20 KNOTS BY LATER WED AND
PROBABLY TO 15 TO 25 KNOTS BY LATE WED NIGHT THUS LIKELY REQUIRING
A SCA.
A LOW SHOULD MOVE EAST ACROSS NORTHERN OH TO NEAR ERI LATE THU INTO
FRI MORNING THEN LIFT SLOWLY NORTH. A CHANGEABLE FLOW WITH THE LOW
WILL EVENTUALLY LINE UP OUT OF THE WEST OR WSW AT ABOUT 15 TO 20
KNOTS FRI SO MARGINAL SCA CONDITIONS MAY OCCUR AS WAVES BUILD. THE
FLOW SHOULD GRADUALLY VEER TO WNW FRI NIGHT WITH MARGINAL SCA
CONDITIONS LIKELY TO CONTINUE UNTIL WINDS DIMINISH LATER SAT.
&&
.HYDROLOGY...
CONCERNS FOR FLOODING FROM LATE TONIGHT THRU FRIDAY. OVERNIGHT THE
FRONTAL BOUNDARY TO OUR NORTH IS PROJECTED TO SINK BACK INTO
NORTHERN OHIO. MEANWHILE THE STRONG STORM SYSTEM OVER THE ROCKIES
WILL BEGIN TRACKING TOWARDS THE PLAINS OVERNIGHT...AND A BROAD AREA
OF 40-50KT 850MB WINDS WILL MOVE INTO THE OHIO VALLEY. THIS JET WILL
INTERSECT WITH THE FRONT AND ADVECT WARM/MOIST AIR FROM THE GULF.
PRECIPITABLE WATER VALUES WILL JUMP TO AROUND 1.35" WHICH IS IN THE
99TH PERCENTILE FOR THIS TIME OF YEAR. THIS UNUSUALLY MOIST AIRMASS
COULD PRODUCE HEAVY RAIN IN ANY THUNDERSTORM DEVELOPMENT. OVERNIGHT
THE GFS AND NAM SUGGEST A WEAK WAVE ALONG THE FRONTAL BOUNDARY OVER
N OH/ NW PA WHICH COULD BE SUCH A CATALYST. THE FRONTAL BOUNDARY
WILL BE MEANDERING IN/NEAR THE REGION UNTIL THE UPPER TROF SWINGS
THROUGH FRI. WILL FOCUS ATTENTION ON THE QUASI-STATIONARY FRONT AS
IT CAN SUPPORT CONVECTION OVER THE SAME AREA FOR A LONG DURATION.
RAINFALL RATES COULD BE UPWARDS OF 1.5" IN 3 HRS WHICH IS ENOUGH TO
PRODUCE FLOODING THIS TIME OF YEAR. SOME FACTORS THAT COULD HELP
SLOW/REDUCE THE FLOODING IS THE DRY WINTER AND THE ONSET OF GROWING
SEASON. HOWEVER THESE FACTORS COULD BE QUICKLY OVERWHELMED IF
RAINFALL RATES ARE HIGH ENOUGH. AT THE TIME OF THIS ISSUANCE THE
HIGHEST RAINFALL AMOUNTS ARE EXPECTED TO OCCUR OVER NORTHERN OHIO
NOTABLY IN THE MAUMEE RIVER BASIN. CANNOT RULE OUT ISOLATED AREAS OF
2 TO 3 INCHES OF RAIN BEFORE THE WORK WEEK IS OUT.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KIELTYKA
NEAR TERM...KEC/KIELTYKA
SHORT TERM...KIELTYKA
LONG TERM...GARNET/YEAGER
AVIATION...KOSARIK
MARINE...ADAMS
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
805 AM EDT WED APR 10 2013
.SYNOPSIS...
AN EAST-WEST FRONTAL BOUNDARY WILL CONTINUE TO WAVER OVER CENTRAL
PENNSYLVANIA INTO THURSDAY. A DYNAMIC STORM SYSTEM CROSSING THE
CENTRAL UNITED STATES WILL SEND A STRONG COLD FRONT THROUGH THE
REGION ON FRIDAY. COOLER TEMPERATURES ARE EXPECTED OVER THE
WEEKEND WITH ANOTHER WARMING TREND LIKELY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED GRIDS WITH LATEST OBSERVATIONS AND TWEAKED TO A MODEL
BLEND OVER NEXT 36 HOURS. THERE STILL ARE SOME SHOWERS NEAR THE
NY/PA BORDER WHERE THERE IS QUITE A PESKY FRONTAL BOUNDARY. THE
LIGHTNING STRIKES IN THESE SHOWERS...MORE TO WEST...IS
DIMINISHING. NICE BOUNDARY WITH TEMPERATURES IN THE 40S ACROSS
SOUTHERN NY AND 5OS ON THE PA SIDE AND ABOUT 80 MILES SOUTH
MORNING TEMPERATURES WERE MORE JUNE-LIKE THAN APRIL WITH READINGS
IN THE 6OS TO LOW 70S.
DEW POINTS IN THE WARM AIR...ON OUR SIDE OF THE BOUNDARY ARE QUITE
HIGH FOR APRIL IN THE 50S. THE OLD 1970S-80S APRIL SEVERE WEATHER
RULE OF DEW POINTS OVER 55 COULD COME INTO PLAY TODAY.
MOST GUIDANCE SHOWS TEMPERATURES IN THE LOWER 80S PUSHING INTO AT
LEAST CENTRAL PA WITH A VERY TIGHT FRONTAL BOUNDARY NEAR THE PA/NY
BORDER. VERY STRONG TEMPERATURE GRADIENT NORTHERN PA/SOUTHERN NY.
TEMPERATURE ERRORS OF 10-15 DEGREES POSSIBLE IN OUR NORTHERN TIER
TODAY DEPENDING ON WHERE THE BOUNDARY SPENDS MOST OF ITS DAY.
ALL GUIDANCE SHOWS AN INSTABILITY SURGE INTO WEST/SOUTHWEST PA. NOT
SURPRISINGLY SLIGHT RISK AREA COMES INTO THE REGION. RAP AND NAM
SOLUTIONS VARY ON THIS TODAY. BUT THERE IS A CLEAR RING-OF-FIRE
FLOW IN OUR REGION WITH A SURGE OF HIGH PW AIR AND STRONG LOW-
LEVEL WESTERLY FLOW COMBINED WITH INSTABILITY IMPLYING AN INCREASED
RISK OF SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON. CAPE
VALUES OF 600-1200JKG-1 IN MOST GUIDANCE ALONG WITH +2SD PW
ANOMALIES IMPLIES TODAY WILL BE MORE LIKE A JUNE THAN APRIL AFTERNOON.
BEST RAIN AND HEAVIEST RAIN WOULD LIKELY BE IN THE STORMS THAT
EVOLVE ALONG AND THE BOUNDARY NEAR THE NY BORDER TODAY. KEPT
CATEGORICAL POPS AND BEST RAINFALL VALUES IN NORTHERN PA AND MUCH
LOWER IN SOUTHERN PA. IF WE GET CONVECTION IT COULD ORGANIZE INTO
BOWING SEGMENTS AND WOULD LIKELY MOVE PRETTY MUCH EAST-EAST-
SOUTHEAST ACROSS THE STATE. PREVIOUS DISCUSSION ALLUDED TO 4KM
NAM CONVECTION IMPLYING SOME BOW-LIKE SEGMENTS LATER THIS
AFTERNOON.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
KEY POINT FOR THURSDAY IS THE BOUNDARY AND HOW FAR SOUTH IT SAGS.
BIG POTENTIAL ERRORS IN TEMPERATURE AND SENSIBLE WEATHER FORECAST
ACROSS MUCH OF NORTHERN THIRD OF PA THURSDAY.
PREVIOUS DISCUSSION....AMPLIFIED UPPER- LEVEL TROUGH WILL EVOLVE OVER THE
CENTRAL CONUS AND TAKE ON A NEGATIVE TILT CROSSING THE MS RVR...AS
SHORTWAVE IMPULSE WITHIN THE BASE OF THE TROUGH ACCELERATES E/NEWD
FROM SRN TX THRU THE LWR MS/TN VLY INTO THE CENTRAL APPALACHIANS.
MEANWHILE...TRIPLE PT LOW FROM DES MOINES IA TO CHICAGO IL WILL
TRACK EWD INTO THE GRT LKS/UPPER OH VLY WITH TRAILING COLD FRONT
SWEEPING EWD TO THE APPALACHIAN SPINE BY 12Z FRI.
CONCEIVABLY THE STNRY/WARM FRONT DRAPED OVER CENTRAL PA SHOULD
LIFT BACK NWD AS THE MIDWEST FRONTAL SYSTEM BEGINS TO LIFT NEWD
TOWARD THE GRT LKS/OH VLY. HOWEVER NAM/GFS SUGGEST A BACKDOOR
SCENARIO MAY OCCUR AS THE BNDRY SLIPS SWD TOWARD THE MASON DIXON
LINE. THE RESULT IS A VERY TRICKY/LOW CONFIDENCE TEMP FCST WITH
BIG-BUST POTENTIAL. BASED ON PREV THINKING...I WEIGHTED THE FINAL
BLEND ON THE WARM-SIDE OF THE GUIDANCE CLOSER TO THE ECMWF/RGEM
FOR TEMPS WHICH WOULD ALLOW FOR ONE MORE VERY MILD DAY. TO GET A
SENSE OF THE UNCERTAINTY...THE SPREAD IN THE GEFS MOS FOR UNV IS
15 DEGS AND 23F IN THE ECENS MOS. PCPN-WISE THE HIGHEST POPS
REMAIN OVER THE NRN TIER DURING THE DAY BUT QUICKLY INCREASE FROM
WEST TO EAST THUR NGT AHEAD OF EWD SURGING COLD FRONT.
THE MEAN POSITION OF THE LARGE SCALE UPPER TROUGH SHOULD REMAIN
CENTERED ACROSS THE GREAT LAKES WITH SEVERAL EMBEDDED SHORTWAVE
IMPULSES GYRATING AROUND THE CENTER. THE MAIN IMPULSE TO INFLUENCE
HEAVY RAIN AND LOW-TOPPED NCFRB POTENTIAL SHOULD CROSS THE REGION
BTWN 12-18Z FRI. THE GFS IS STILL ABOUT 6HRS FASTER THAN THE ECMWF
IN SHIFTING ITS HVY QPF AXIS OUT OF CENTRAL PA. STRONG DYNAMICS
COUPLED WITH AMPLE MSTR/HIGH PWATS SHOULD LEAD TO MOD TO LOCALLY
HEAVY RAFL AMTS ALONG THE FRONTAL BAND. CONDS WILL DRY OUT LATER
FRI AFTN INTO FRI NGT WITH ANOTHER S/W AND SECONDARY COLD FRONT
PUSHING EWD THROUGH THE CWA...USHERING IN THE COOLER AIR FOR THE
WEEKEND. SCT RA/SN SHOWERS ARE POSSIBLE FRI NGT IN THE FAVORED
UPSLOPE AREAS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
CYCLONIC FLOW PATTERN WILL PREVAIL THROUGH THE WEEKEND AS UPPER
LOW MOVES EWD THRU ONTARIO AND NRN MAINE. ANOTHER S/W TROUGH
SHOULD SWEEP THROUGH ON SATURDAY AND MAY TRIGGER A BAND OF
SHOWERS. HIGH PRESSURE WILL BUILD INTO THE CWA ON SUNDAY. TEMPS
SHOULD AVG NEAR TO BELOW NORMAL BEFORE MODERATING INTO EARLY NEXT
WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
CURRENTLY SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS THE
NORTHERN TIER OF PA BRINGING IFR CIGS AND VSBYS TO BFD. EXPECT
THESE PERIODS OF IFR AND MAINLY MVFR CIGS AND VSBYS THROUGH MOST
OF THE DAY. THESE CONDITIONS WILL SLOWLY SPREAD OVER THE WESTERN
AND CENTRAL TAF SITES THROUGH MIDDAY. THE SOUTHEASTERN TAF SITES
SHOULD REMAIN VFR TODAY...THROUGH AFTERNOON CONVECTION ASSOCIATED
WITH THE STATIONARY BOUNDARY DRAPED ACROSS PA COULD ALLOW FOR
BRIEF PERIODS OF MVFR CONDITIONS LATE THIS AFTERNOON...AND EARLY
EVENING.
THIS BOUNDARY IS EXPECTED TO REMAIN IN THE VICINITY OF CNTRL PA
THRU TODAY AND TONIGHT. BFD SHOULD BE ENTRENCHED IN THE LOW
STRATOCU OVERNIGHT. THE BOUNDARY WILL MAKE ITS WAY SLOWLY EASTWARD
THURSDAY INTO FRIDAY.
.OUTLOOK...
THU...EARLY AM LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS NORTH.
FRI...RAIN/LOW CIGS POSS...ESP EARLY. SHRA POSS NW PM.
SAT-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...STEINBUGL
SHORT TERM...STEINBUGL
LONG TERM...STEINBUGL
AVIATION...CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
757 AM EDT WED APR 10 2013
.SYNOPSIS...
AN EAST-WEST FRONTAL BOUNDARY WILL CONTINUE TO WAVER OVER CENTRAL
PENNSYLVANIA INTO THURSDAY. A DYNAMIC STORM SYSTEM CROSSING THE
CENTRAL UNITED STATES WILL SEND A STRONG COLD FRONT THROUGH THE
REGION ON FRIDAY. COOLER TEMPERATURES ARE EXPECTED OVER THE
WEEKEND WITH ANOTHER WARMING TREND LIKELY INTO EARLY NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED GRIDS WITH LATEST OBSERVATIONS AND TWEAKED TO A MODEL
BLEND OVER NEXT 36 HOURS. THERE STILL ARE SOME SHOWERS NEAR THE
NY/PA BORDER WHERE THERE IS QUITE A PESKY FRONTAL BOUNDARY. THE
LIGHTNING STRIKES IN THESE SHOWERS...MORE TO WEST...IS
DIMINISHING. NICE BOUNDARY WITH TEMPERATURES IN THE 40S ACROSS
SOUTHERN NY AND 5OS ON THE PA SIDE AND ABOUT 80 MILES SOUTH
MORNING TEMPERATURES WERE MORE JUNE-LIKE THAN APRIL WITH READINGS
IN THE 6OS TO LOW 70S.
DEW POINTS IN THE WARM AIR...ON OUR SIDE OF THE BOUNDARY ARE QUITE
HIGH FOR APRIL IN THE 50S. THE OLD 1970S-80S APRIL SEVERE WEATHER
RULE OF DEW POINTS OVER 55 COULD COME INTO PLAY TODAY.
MOST GUIDANCE SHOWS TEMPERATURES IN THE LOWER 80S PUSHING INTO AT
LEAST CENTRAL PA WITH A VERY TIGHT FRONTAL BOUNDARY NEAR THE PA/NY
BORDER. VERY STRONG TEMPERATURE GRADIENT NORTHERN PA/SOUTHERN NY.
TEMPERATURE ERRORS OF 10-15 DEGREES POSSIBLE IN OUR NORTHERN TIER
TODAY DEPENDING ON WHERE THE BOUNDARY SPENDS MOST OF ITS DAY.
ALL GUIDANCE SHOWS AN INSTABILITY SURGE INTO WEST/SOUTHWEST PA. NOT
SURPRISINGLY SLIGHT RISK AREA COMES INTO THE REGION. RAP AND NAM
SOLUTIONS VARY ON THIS TODAY. BUT THERE IS A CLEAR RING-OF-FIRE
FLOW IN OUR REGION WITH A SURGE OF HIGH PW AIR AND STRONG LOW-
LEVEL WESTERLY FLOW COMBINED WITH INSTABILITY IMPLYING AN INCREASED
RISK OF SHOWERS AND THUNDERSTORMS DEVELOPING THIS AFTERNOON. CAPE
VALUES OF 600-1200JKG-1 IN MOST GUIDANCE ALONG WITH +2SD PW
ANOMALIES IMPLIES TODAY WILL BE MORE LIKE A JUNE THAN APRIL AFTERNOON.
BEST RAIN AND HEAVIEST RAIN WOULD LIKELY BE IN THE STORMS THAT
EVOLVE ALONG AND THE BOUNDARY NEAR THE NY BORDER TODAY. KEPT
CATEGORICAL POPS AND BEST RAINFALL VALUES IN NORTHERN PA AND MUCH
LOWER IN SOUTHERN PA. IF WE GET CONVECTION IT COULD ORGANIZE INTO
BOWING SEGMENTS AND WOULD LIKELY MOVE PRETTY MUCH EAST-EAST-
SOUTHEAST ACROSS THE STATE. PREVIOUS DISCUSSION ALLUDED TO 4KM
NAM CONVECTION IMPLYING SOME BOW-LIKE SEGMENTS LATER THIS
AFTERNOON.
&&
.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
KEY POINT FOR THURSDAY IS THE BOUNDARY AND HOW FAR SOUTH IT SAGS.
BIG POTENTIAL ERRORS IN TEMPERATURE AND SENSIBLE WEATHER FORECAST
ACROSS MUCH OF NORTHERN THIRD OF PA THURSDAY.
PREVIOUS DISCUSSION....AMPLIFIED UPPER- LEVEL TROUGH WILL EVOLVE OVER THE
CENTRAL CONUS AND TAKE ON A NEGATIVE TILT CROSSING THE MS RVR...AS
SHORTWAVE IMPULSE WITHIN THE BASE OF THE TROUGH ACCELERATES E/NEWD
FROM SRN TX THRU THE LWR MS/TN VLY INTO THE CENTRAL APPALACHIANS.
MEANWHILE...TRIPLE PT LOW FROM DES MOINES IA TO CHICAGO IL WILL
TRACK EWD INTO THE GRT LKS/UPPER OH VLY WITH TRAILING COLD FRONT
SWEEPING EWD TO THE APPALACHIAN SPINE BY 12Z FRI.
CONCEIVABLY THE STNRY/WARM FRONT DRAPED OVER CENTRAL PA SHOULD
LIFT BACK NWD AS THE MIDWEST FRONTAL SYSTEM BEGINS TO LIFT NEWD
TOWARD THE GRT LKS/OH VLY. HOWEVER NAM/GFS SUGGEST A BACKDOOR
SCENARIO MAY OCCUR AS THE BNDRY SLIPS SWD TOWARD THE MASON DIXON
LINE. THE RESULT IS A VERY TRICKY/LOW CONFIDENCE TEMP FCST WITH
BIG-BUST POTENTIAL. BASED ON PREV THINKING...I WEIGHTED THE FINAL
BLEND ON THE WARM-SIDE OF THE GUIDANCE CLOSER TO THE ECMWF/RGEM
FOR TEMPS WHICH WOULD ALLOW FOR ONE MORE VERY MILD DAY. TO GET A
SENSE OF THE UNCERTAINTY...THE SPREAD IN THE GEFS MOS FOR UNV IS
15 DEGS AND 23F IN THE ECENS MOS. PCPN-WISE THE HIGHEST POPS
REMAIN OVER THE NRN TIER DURING THE DAY BUT QUICKLY INCREASE FROM
WEST TO EAST THUR NGT AHEAD OF EWD SURGING COLD FRONT.
THE MEAN POSITION OF THE LARGE SCALE UPPER TROUGH SHOULD REMAIN
CENTERED ACROSS THE GREAT LAKES WITH SEVERAL EMBEDDED SHORTWAVE
IMPULSES GYRATING AROUND THE CENTER. THE MAIN IMPULSE TO INFLUENCE
HEAVY RAIN AND LOW-TOPPED NCFRB POTENTIAL SHOULD CROSS THE REGION
BTWN 12-18Z FRI. THE GFS IS STILL ABOUT 6HRS FASTER THAN THE ECMWF
IN SHIFTING ITS HVY QPF AXIS OUT OF CENTRAL PA. STRONG DYNAMICS
COUPLED WITH AMPLE MSTR/HIGH PWATS SHOULD LEAD TO MOD TO LOCALLY
HEAVY RAFL AMTS ALONG THE FRONTAL BAND. CONDS WILL DRY OUT LATER
FRI AFTN INTO FRI NGT WITH ANOTHER S/W AND SECONDARY COLD FRONT
PUSHING EWD THROUGH THE CWA...USHERING IN THE COOLER AIR FOR THE
WEEKEND. SCT RA/SN SHOWERS ARE POSSIBLE FRI NGT IN THE FAVORED
UPSLOPE AREAS.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
CYCLONIC FLOW PATTERN WILL PREVAIL THROUGH THE WEEKEND AS UPPER
LOW MOVES EWD THRU ONTARIO AND NRN MAINE. ANOTHER S/W TROUGH
SHOULD SWEEP THROUGH ON SATURDAY AND MAY TRIGGER A BAND OF
SHOWERS. HIGH PRESSURE WILL BUILD INTO THE CWA ON SUNDAY. TEMPS
SHOULD AVG NEAR TO BELOW NORMAL BEFORE MODERATING INTO EARLY NEXT
WEEK.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
STATIONARY BOUNDARY HAS DROPPED SOUTH OF THE NEW YORK
BORDER...CURRENTLY BRINGING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ACROSS THE NORTHERN TIER OF PA.
PERIODS OF MVFR CIGS AND VSBYS SHOULD REDUCE CONDITIONS MAINLY
AT BFD.
THIS BOUNDARY IS EXPECTED TO REMAIN IN THE VICINITY OF CNTRL PA
THRU AT LEAST TODAY. EXPECT THESE SHOWERS AND THUNDERSTORMS TO
INTENSIFY THIS AFTERNOON AND EARLY EVENING. THE BEST CHANCE FOR
RAIN/THUNDER SHOWERS AND REDUCING CONDITIONS WILL BE OVER CENTRAL
AND NRN TERMINALS...THIS AFTERNOON. DOWNSLOPE FLOW COULD ALLOW FOR
POSSIBLE MVFR CIGS AND VSBYS AT JST...AOO AS WELL..THOUGH THE
SOUTHEASTERN SITES SHOULD REMAIN MAINLY IF NOT COMPLETELY VFR.
.OUTLOOK...
THU...EARLY AM LOW CIGS POSS NW MTNS. PM TSRA IMPACTS POSS NORTH.
FRI...RAIN/LOW CIGS POSS...ESP EARLY. SHRA POSS NW PM.
SAT-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...STEINBUGL
NEAR TERM...GRUMM/STEINBUGL
SHORT TERM...STEINBUGL/GRUMM
LONG TERM...STEINBUGL
AVIATION...CERU
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
141 PM CDT WED APR 10 2013
.UPDATE...FOR 18Z TAFS.
&&
.AVIATION...
STORM SYSTEM/COLD FRONT EXPECTED TO MOVE INTO THE AREA EARLY THU.
THIS WILL BRING SHOWERS/STORMS TO CKV/BNA ROUGHLY 12Z-18Z THU...
AND FURTHER EAST LATER IN THE DAY. CONDITIONS WILL LIKELY REMAIN
VFR TIL AFT 12Z THU WHEN LOWERING CLOUDS AND REDUCED VSBYS FROM
CONVECTION OCCUR. CONDITIONS LIKELY MVFR CKV/BNA BY THE END OF THE
PERIOD.
&&
.PREV DISCUSSION... /ISSUED 1005 AM CDT WED APR 10 2013/
UPDATE...
STARTING TO SEE ISOLATED LIGHT SHOWERS OR SPRINKLES DOWN IN THE
DELTA REGION OF MISSISSIPPI NORTHWARD THROUGH THE MEMPHIS AREA. AM
EXPECTING THIS ACTIVITY TO PICK UP IN COVERAGE AS WE GO TOWARD
1 PM WHILE ADVANCING NORTHWARD...BUT IT SHOULD STAY MOSTLY WEST OF
TENNESSEE RIVER. EXPECT WE COULD SEE AN ISOLATED THUNDERSTORM OR
TWO IN FAR WESTERN TENNESSEE BEFORE 1 PM. THIS IN AREA OF HIGHER
CAPES. I EXPECT WE COULD ALSO SEE A FEW SHOWERS WORK INTO
NORTHWEST MIDDLE TENNESSEE DURING THE AFTERNOON AROUND DOVER AND
CLARKSVILLE AREAS.
COLD FRONT STILL WELL TO OUR WEST NEAR FORT SMITH. COLDER AIR HAS
UNDERCUT THUNDERSTORM ACTIVITY...WITH STORMS NOW BEING ELEVATED.
COLD FRONT WILL ADVANCE EASTWARD TODAY AND TONIGHT WITH A LINE OF
STORMS MOVING ALONG MISSISSIPPI RIVER ABOUT 1 AM CDT THEN ALONG
THE TENNESSEE RIVER/FAR WESTERN MIDDLE TENNESSEE AROUND 8 AM CDT
THURSDAY. SREF HAS CONTINUED WITH LESSENING THE THREAT FOR SEVERE
WEATHER ONCE STORMS APPROACH TENNESSEE RIVER LATE TONIGHT/EARLY
THURSDAY. HOWEVER...SREF HAS BEEN SOMEWHAT CONSISTENT IN INTENSIFYING
THE LINE OF STORMS ONCE APPROACHING INTERSTATE 65 FROM MID TO LATE
MORNING THROUGH THE AFTERNOON AS THE LINE CONTINUES EASTWARD AND
ONTO THE PLATEAU. I STILL THINK THE MAIN THREAT WILL BE DAMAGING
STRAIGHT LINE WINDS BUT CANT RULE OUT AN ISOLATED TWISTER OR TWO
IN MIDDLE TENNESSEE.
CLIMATE...FOR THE FIRST THREE MONTHS OF THIS YEAR THERE HAVE
BEEN 27 TORNADOES IN TENNESSEE WITH NO FATALITIES. LAST YEAR FOR
THE SAME PERIOD WE ALSO HAD 27 TORNADOES BUT WITH 3 FATALITIES.
BOYD
PREV DISCUSSION... /ISSUED 609 AM CDT WED APR 10 2013/
AVIATION 12Z DISCUSSION...
SFC WINDS WILL BE ON THE INCREASE TODAY AS A STORM SYSTEM DEVELOPS
TO OUR WEST AND THE PRESSURE GRADIENT TIGHTENS. TOWARD THE END OF
THE TAF PD...A SQUALL LINE WILL LIKELY DEVELOP WITH STRONG TO
SEVERE TSTMS APPROACHING. CLOUDS WILL LOWER AFTER 00Z WITH TSTM
CHANCES COMMENCING AROUND 08Z FOR CKV...AROUND OR JUST BEYOND 12Z
FOR BNA.
PREV DISCUSSION... /ISSUED 302 AM CDT WED APR 10 2013/
DISCUSSION...
WARMEST DAY OF THE YEAR ON TAP TODAY WITH STRENGTHENING SOUTHERLY
FLOW. AFTER LOOKING AT UPSTREAM HIGHS YDAY WENT AOA MAV TEMPS ACRS
THE BOARD. DON;T SEE MUCH IN THE WAY OF FORCING/TRIGGER FOR
CONVECTION TDY BUT WILL MAINTAIN LOW POPS NW WHERE MSTR WILL BE
DEEPEST. WINDS WILL BECOME GUSTY THIS AFTN BUT SHUD REMAIN BLO
ADVSRY CRITERIA.
SOMEWHAT BETTER TIMING AGREEMENT FOR NEXT SYS AMONG THE 00Z
MODELS WITH THE GFS STILL FAST AND THE EURO SLOW. THE NAM IS A
DECENT COMPROMISE...AND ALSO HAS A BETTER HANDLE ON THE SHALLOW
COLD AIR MASS BEHIND THIS SYS...SO IT WAS USED TO FINE TUNE THE
FCST DETAILS ASSOCIATED WITH THE FORTHCOMING FROPA. MOST LIKELY
SCENARIO LOOKS TO BE A DIURNALLY WEAKENING SQUALL LINE ENTERING
WESTERN SXNS IN THE EARLY MORNING HOURS AND REACHING THE I-65
CORRIDOR BY MIDDAY. SOME SEVERE WEATHER...MAINLY STRAIGHT LINE
WINDS...REMAINS POSSIBLE DURING THIS PERIOD GIVEN THE KINEMATICS
AND AT LEAST SOME INSTABILITY.
SOME QSTN REMAINS ABT THE DEGREE OF HEATING EASTERN SXNS WL RECEIVE
THURSDAY BUT THERE DEFINITELY WILL BE SOME...AND AS THE LLVLS
DESTABILIZE XPCT TO SEE CONVECTION INTENSIFY AGAIN MAINLY EAST OF
I-65. TSTMS WILL BE ADDITIONALLY ENHANCED AS WE COME UNDER THE
INFLUENCE OF THE RR QUAD A PRONOUNCED UPPER JET. A WAVE OF LOW PRES
IS EXPECTED TO DVLP ALONG THE FRONT WHICH IN ADDITION TO SLOWING
THE FRONT COULD ACT TO LOCALLY ENHANCE SHEAR AS STORMS AFFECT
EASTERN SXNS. THIS WILL ALL HAPPEN IN THE MESOSCALE AND WE`LL
LIKELY HAVE TO WAIT UNTIL THU TO SEE HOW THIS WILL PLAY OUT. AT
ANY RATE WE REMAIN UNDER A SLIGHT RISK FOR SEVERE TSTMS THU WITH
GREATER SEVERE CHANCES...DAMAGING WINDS AND ISOLATED TORNADOES...AS
YOU HEAD EAST
PRECIP WILL LINGER THRU MIDNIGHT ON/NEAR THE PLATEAU THEN A DEEP
DRYING OF THE ATMOS COMMENCES. LOOKING AT THE AIRMASS
CHARACTERISTICS UPSTREAM HAVE LEANED TOWARD THE MUCH COLDER MET
GUIDANCE FOR HIGHS FRIDAY. BEYOND THAT THE AIRMASS WILL MODIFY
THROUGH THE WEEKEND UNDER A STRONG APRIL SUN AND DEEPENING
RIDGING. STILL LOOKS LIKE POTNL FOR SCT/WIDELY SCT CONVECTION
MON/TUE AS DEEPER MSTR RETURNS. NEXT STRONGER SYS LOOKS TO AFFECT
THE AREA DURING THE MIDDLE OF NEXT WEEK.
HYDROLOGY...
1 TO 2 INCHES OF RAIN IS EXPECTED AREA WIDE FROM LATE TONIGHT
THROUGH THURSDAY EVENING. GIVEN THE RECENT DRY CONDITIONS (LESS
THAN 0.25 FOR MOST SPOTS SO FAR THIS MONTH) AND LOWERED RIVER
LEVELS WE ARE NOT EXPECTING WIDESPREAD FLOODING ISSUES. SOME
LOCALIZED FLOODING COULD DEVELOP HWVR...ESPECIALLY IN ANY AREAS
WHERE HEAVY THUNDERSTORM RAINS PERSIST FOR AN EXTENDED PERIOD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
07
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1005 AM CDT WED APR 10 2013
.UPDATE...
STARTING TO SEE ISOLATED LIGHT SHOWERS OR SPRINKLES DOWN IN THE
DELTA REGION OF MISSISSIPPI NORTHWARD THROUGH THE MEMPHIS AREA. AM
EXPECTING THIS ACTIVITY TO PICK UP IN COVERAGE AS WE GO TOWARD
1 PM WHILE ADVANCING NORTHWARD...BUT IT SHOULD STAY MOSTLY WEST OF
TENNESSEE RIVER. EXPECT WE COULD SEE AN ISOLATED THUNDERSTORM OR
TWO IN FAR WESTERN TENNESSEE BEFORE 1 PM. THIS IN AREA OF HIGHER
CAPES. I EXPECT WE COULD ALSO SEE A FEW SHOWERS WORK INTO
NORTHWEST MIDDLE TENNESSEE DURING THE AFTERNOON AROUND DOVER AND
CLARKSVILLE AREAS.
COLD FRONT STILL WELL TO OUR WEST NEAR FORT SMITH. COLDER AIR HAS
UNDERCUT THUNDERSTORM ACTIVITY...WITH STORMS NOW BEING ELEVATED.
COLD FRONT WILL ADVANCE EASTWARD TODAY AND TONIGHT WITH A LINE OF
STORMS MOVING ALONG MISSISSIPPI RIVER ABOUT 1 AM CDT THEN ALONG
THE TENNESSEE RIVER/FAR WESTERN MIDDLE TENNESSEE AROUND 8 AM CDT
THURSDAY. SREF HAS CONTINUED WITH LESSENING THE THREAT FOR SEVERE
WEATHER ONCE STORMS APPROACH TENNESSEE RIVER LATE TONIGHT/EARLY
THURSDAY. HOWEVER...SREF HAS BEEN SOMEWHAT CONSISTENT IN INTENSIFYING
THE LINE OF STORMS ONCE APPROACHING INTERSTATE 65 FROM MID TO LATE
MORNING THROUGH THE AFTERNOON AS THE LINE CONTINUES EASTWARD AND
ONTO THE PLATEAU. I STILL THINK THE MAIN THREAT WILL BE DAMAGING
STRAIGHT LINE WINDS BUT CANT RULE OUT AN ISOLATED TWISTER OR TWO
IN MIDDLE TENNESSEE.
.CLIMATE...FOR THE FIRST THREE MONTHS OF THIS YEAR THERE HAVE
BEEN 27 TORNADOES IN TENNESSEE WITH NO FATALITIES. LAST YEAR FOR
THE SAME PERIOD WE ALSO HAD 27 TORNADOES BUT WITH 3 FATALITIES.
BOYD
&&
.PREV DISCUSSION... /ISSUED 609 AM CDT WED APR 10 2013/
AVIATION 12Z DISCUSSION...
SFC WINDS WILL BE ON THE INCREASE TODAY AS A STORM SYSTEM DEVELOPS
TO OUR WEST AND THE PRESSURE GRADIENT TIGHTENS. TOWARD THE END OF
THE TAF PD...A SQUALL LINE WILL LIKELY DEVELOP WITH STRONG TO
SEVERE TSTMS APPROACHING. CLOUDS WILL LOWER AFTER 00Z WITH TSTM
CHANCES COMMENCING AROUND 08Z FOR CKV...AROUND OR JUST BEYOND 12Z
FOR BNA.
PREV DISCUSSION... /ISSUED 302 AM CDT WED APR 10 2013/
DISCUSSION...
WARMEST DAY OF THE YEAR ON TAP TODAY WITH STRENGTHENING SOUTHERLY
FLOW. AFTER LOOKING AT UPSTREAM HIGHS YDAY WENT AOA MAV TEMPS ACRS
THE BOARD. DON;T SEE MUCH IN THE WAY OF FORCING/TRIGGER FOR
CONVECTION TDY BUT WILL MAINTAIN LOW POPS NW WHERE MSTR WILL BE
DEEPEST. WINDS WILL BECOME GUSTY THIS AFTN BUT SHUD REMAIN BLO
ADVSRY CRITERIA.
SOMEWHAT BETTER TIMING AGREEMENT FOR NEXT SYS AMONG THE 00Z
MODELS WITH THE GFS STILL FAST AND THE EURO SLOW. THE NAM IS A
DECENT COMPROMISE...AND ALSO HAS A BETTER HANDLE ON THE SHALLOW
COLD AIR MASS BEHIND THIS SYS...SO IT WAS USED TO FINE TUNE THE
FCST DETAILS ASSOCIATED WITH THE FORTHCOMING FROPA. MOST LIKELY
SCENARIO LOOKS TO BE A DIURNALLY WEAKENING SQUALL LINE ENTERING
WESTERN SXNS IN THE EARLY MORNING HOURS AND REACHING THE I-65
CORRIDOR BY MIDDAY. SOME SEVERE WEATHER...MAINLY STRAIGHT LINE
WINDS...REMAINS POSSIBLE DURING THIS PERIOD GIVEN THE KINEMATICS
AND AT LEAST SOME INSTABILITY.
SOME QSTN REMAINS ABT THE DEGREE OF HEATING EASTERN SXNS WL RECEIVE
THURSDAY BUT THERE DEFINITELY WILL BE SOME...AND AS THE LLVLS
DESTABILIZE XPCT TO SEE CONVECTION INTENSIFY AGAIN MAINLY EAST OF
I-65. TSTMS WILL BE ADDITIONALLY ENHANCED AS WE COME UNDER THE
INFLUENCE OF THE RR QUAD A PRONOUNCED UPPER JET. A WAVE OF LOW PRES
IS EXPECTED TO DVLP ALONG THE FRONT WHICH IN ADDITION TO SLOWING
THE FRONT COULD ACT TO LOCALLY ENHANCE SHEAR AS STORMS AFFECT
EASTERN SXNS. THIS WILL ALL HAPPEN IN THE MESOSCALE AND WE`LL
LIKELY HAVE TO WAIT UNTIL THU TO SEE HOW THIS WILL PLAY OUT. AT
ANY RATE WE REMAIN UNDER A SLIGHT RISK FOR SEVERE TSTMS THU WITH
GREATER SEVERE CHANCES...DAMAGING WINDS AND ISOLATED TORNADOES...AS
YOU HEAD EAST
PRECIP WILL LINGER THRU MIDNIGHT ON/NEAR THE PLATEAU THEN A DEEP
DRYING OF THE ATMOS COMMENCES. LOOKING AT THE AIRMASS
CHARACTERISTICS UPSTREAM HAVE LEANED TOWARD THE MUCH COLDER MET
GUIDANCE FOR HIGHS FRIDAY. BEYOND THAT THE AIRMASS WILL MODIFY
THROUGH THE WEEKEND UNDER A STRONG APRIL SUN AND DEEPENING
RIDGING. STILL LOOKS LIKE POTNL FOR SCT/WIDELY SCT CONVECTION
MON/TUE AS DEEPER MSTR RETURNS. NEXT STRONGER SYS LOOKS TO AFFECT
THE AREA DURING THE MIDDLE OF NEXT WEEK.
HYDROLOGY...
1 TO 2 INCHES OF RAIN IS EXPECTED AREA WIDE FROM LATE TONIGHT
THROUGH THURSDAY EVENING. GIVEN THE RECENT DRY CONDITIONS (LESS
THAN 0.25 FOR MOST SPOTS SO FAR THIS MONTH) AND LOWERED RIVER
LEVELS WE ARE NOT EXPECTING WIDESPREAD FLOODING ISSUES. SOME
LOCALIZED FLOODING COULD DEVELOP HWVR...ESPECIALLY IN ANY AREAS
WHERE HEAVY THUNDERSTORM RAINS PERSIST FOR AN EXTENDED PERIOD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
609 AM CDT WED APR 10 2013
.AVIATION 12Z DISCUSSION...
SFC WINDS WILL BE ON THE INCREASE TODAY AS A STORM SYSTEM DEVELOPS
TO OUR WEST AND THE PRESSURE GRADIENT TIGHTENS. TOWARD THE END OF
THE TAF PD...A SQUALL LINE WILL LIKELY DEVELOP WITH STRONG TO
SEVERE TSTMS APPROACHING. CLOUDS WILL LOWER AFTER 00Z WITH TSTM
CHANCES COMMENCING AROUND 08Z FOR CKV...AROUND OR JUST BEYOND 12Z
FOR BNA.
&&
.PREV DISCUSSION... /ISSUED 302 AM CDT WED APR 10 2013/
DISCUSSION...
WARMEST DAY OF THE YEAR ON TAP TODAY WITH STRENGTHENING SOUTHERLY
FLOW. AFTER LOOKING AT UPSTREAM HIGHS YDAY WENT AOA MAV TEMPS ACRS
THE BOARD. DON;T SEE MUCH IN THE WAY OF FORCING/TRIGGER FOR
CONVECTION TDY BUT WILL MAINTAIN LOW POPS NW WHERE MSTR WILL BE
DEEPEST. WINDS WILL BECOME GUSTY THIS AFTN BUT SHUD REMAIN BLO
ADVSRY CRITERIA.
SOMEWHAT BETTER TIMING AGREEMENT FOR NEXT SYS AMONG THE 00Z
MODELS WITH THE GFS STILL FAST AND THE EURO SLOW. THE NAM IS A
DECENT COMPROMISE...AND ALSO HAS A BETTER HANDLE ON THE SHALLOW
COLD AIR MASS BEHIND THIS SYS...SO IT WAS USED TO FINE TUNE THE
FCST DETAILS ASSOCIATED WITH THE FORTHCOMING FROPA. MOST LIKELY
SCENARIO LOOKS TO BE A DIURNALLY WEAKENING SQUALL LINE ENTERING
WESTERN SXNS IN THE EARLY MORNING HOURS AND REACHING THE I-65
CORRIDOR BY MIDDAY. SOME SEVERE WEATHER...MAINLY STRAIGHT LINE
WINDS...REMAINS POSSIBLE DURING THIS PERIOD GIVEN THE KINEMATICS
AND AT LEAST SOME INSTABILITY.
SOME QSTN REMAINS ABT THE DEGREE OF HEATING EASTERN SXNS WL RECEIVE
THURSDAY BUT THERE DEFINITELY WILL BE SOME...AND AS THE LLVLS
DESTABILIZE XPCT TO SEE CONVECTION INTENSIFY AGAIN MAINLY EAST OF
I-65. TSTMS WILL BE ADDITIONALLY ENHANCED AS WE COME UNDER THE
INFLUENCE OF THE RR QUAD A PRONOUNCED UPPER JET. A WAVE OF LOW PRES
IS EXPECTED TO DVLP ALONG THE FRONT WHICH IN ADDITION TO SLOWING
THE FRONT COULD ACT TO LOCALLY ENHANCE SHEAR AS STORMS AFFECT
EASTERN SXNS. THIS WILL ALL HAPPEN IN THE MESOSCALE AND WE`LL
LIKELY HAVE TO WAIT UNTIL THU TO SEE HOW THIS WILL PLAY OUT. AT
ANY RATE WE REMAIN UNDER A SLIGHT RISK FOR SEVERE TSTMS THU WITH
GREATER SEVERE CHANCES...DAMAGING WINDS AND ISOLATED TORNADOES...AS
YOU HEAD EAST
PRECIP WILL LINGER THRU MIDNIGHT ON/NEAR THE PLATEAU THEN A DEEP
DRYING OF THE ATMOS COMMENCES. LOOKING AT THE AIRMASS
CHARACTERISTICS UPSTREAM HAVE LEANED TOWARD THE MUCH COLDER MET
GUIDANCE FOR HIGHS FRIDAY. BEYOND THAT THE AIRMASS WILL MODIFY
THROUGH THE WEEKEND UNDER A STRONG APRIL SUN AND DEEPENING
RIDGING. STILL LOOKS LIKE POTNL FOR SCT/WIDELY SCT CONVECTION
MON/TUE AS DEEPER MSTR RETURNS. NEXT STRONGER SYS LOOKS TO AFFECT
THE AREA DURING THE MIDDLE OF NEXT WEEK.
HYDROLOGY...
1 TO 2 INCHES OF RAIN IS EXPECTED AREA WIDE FROM LATE TONIGHT
THROUGH THURSDAY EVENING. GIVEN THE RECENT DRY CONDITIONS (LESS
THAN 0.25 FOR MOST SPOTS SO FAR THIS MONTH) AND LOWERED RIVER
LEVELS WE ARE NOT EXPECTING WIDESPREAD FLOODING ISSUES. SOME
LOCALIZED FLOODING COULD DEVELOP HWVR...ESPECIALLY IN ANY AREAS
WHERE HEAVY THUNDERSTORM RAINS PERSIST FOR AN EXTENDED PERIOD.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
21
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
302 AM CDT WED APR 10 2013
.DISCUSSION...
WARMEST DAY OF THE YEAR ON TAP TODAY WITH STRENGTHENING SOUTHERLY
FLOW. AFTER LOOKING AT UPSTREAM HIGHS YDAY WENT AOA MAV TEMPS ACRS
THE BOARD. DON;T SEE MUCH IN THE WAY OF FORCING/TRIGGER FOR
CONVECTION TDY BUT WILL MAINTAIN LOW POPS NW WHERE MSTR WILL BE
DEEPEST. WINDS WILL BECOME GUSTY THIS AFTN BUT SHUD REMAIN BLO
ADVSRY CRITERIA.
SOMEWHAT BETTER TIMING AGREEMENT FOR NEXT SYS AMONG THE 00Z
MODELS WITH THE GFS STILL FAST AND THE EURO SLOW. THE NAM IS A
DECENT COMPROMISE...AND ALSO HAS A BETTER HANDLE ON THE SHALLOW
COLD AIR MASS BEHIND THIS SYS...SO IT WAS USED TO FINE TUNE THE
FCST DETAILS ASSOCIATED WITH THE FORTHCOMING FROPA. MOST LIKELY
SCENARIO LOOKS TO BE A DIURNALLY WEAKENING SQUALL LINE ENTERING
WESTERN SXNS IN THE EARLY MORNING HOURS AND REACHING THE I-65
CORRIDOR BY MIDDAY. SOME SEVERE WEATHER...MAINLY STRAIGHT LINE
WINDS...REMAINS POSSIBLE DURING THIS PERIOD GIVEN THE KINEMATICS
AND AT LEAST SOME INSTABILITY.
SOME QSTN REMAINS ABT THE DEGREE OF HEATING EASTERN SXNS WL RECEIVE
THURSDAY BUT THERE DEFINITELY WILL BE SOME...AND AS THE LLVLS
DESTABILIZE XPCT TO SEE CONVECTION INTENSIFY AGAIN MAINLY EAST OF
I-65. TSTMS WILL BE ADDITIONALLY ENHANCED AS WE COME UNDER THE
INFLUENCE OF THE RR QUAD A PRONOUNCED UPPER JET. A WAVE OF LOW PRES
IS EXPECTED TO DVLP ALONG THE FRONT WHICH IN ADDITION TO SLOWING
THE FRONT COULD ACT TO LOCALLY ENHANCE SHEAR AS STORMS AFFECT
EASTERN SXNS. THIS WILL ALL HAPPEN IN THE MESOSCALE AND WE`LL
LIKELY HAVE TO WAIT UNTIL THU TO SEE HOW THIS WILL PLAY OUT. AT
ANY RATE WE REMAIN UNDER A SLIGHT RISK FOR SEVERE TSTMS THU WITH
GREATER SEVERE CHANCES...DAMAGING WINDS AND ISOLATED TORNADOES...AS
YOU HEAD EAST
PRECIP WILL LINGER THRU MIDNIGHT ON/NEAR THE PLATEAU THEN A DEEP
DRYING OF THE ATMOS COMMENCES. LOOKING AT THE AIRMASS
CHARACTERISTICS UPSTREAM HAVE LEANED TOWARD THE MUCH COLDER MET
GUIDANCE FOR HIGHS FRIDAY. BEYOND THAT THE AIRMASS WILL MODIFY
THROUGH THE WEEKEND UNDER A STRONG APRIL SUN AND DEEPENING
RIDGING. STILL LOOKS LIKE POTNL FOR SCT/WIDELY SCT CONVECTION
MON/TUE AS DEEPER MSTR RETURNS. NEXT STRONGER SYS LOOKS TO AFFECT
THE AREA DURING THE MIDDLE OF NEXT WEEK.
&&
.HYDROLOGY...
1 TO 2 INCHES OF RAIN IS EXPECTED AREA WIDE FROM LATE TONIGHT
THROUGH THURSDAY EVENING. GIVEN THE RECENT DRY CONDITIONS (LESS
THAN 0.25 FOR MOST SPOTS SO FAR THIS MONTH) AND LOWERED RIVER
LEVELS WE ARE NOT EXPECTING WIDESPREAD FLOODING ISSUES. SOME
LOCALIZED FLOODING COULD DEVELOP HWVR...ESPECIALLY IN ANY AREAS
WHERE HEAVY THUNDERSTORM RAINS PERSIST FOR AN EXTENDED PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
NASHVILLE 83 64 69 44 / 10 70 100 70
CLARKSVILLE 82 63 65 42 / 20 90 90 50
CROSSVILLE 80 61 69 45 / 10 50 100 100
COLUMBIA 83 63 69 44 / 10 70 100 70
LAWRENCEBURG 83 63 68 43 / 10 80 100 70
WAVERLY 83 62 65 42 / 20 90 90 50
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
JOHNSTONE
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
313 PM CDT WED APR 10 2013
.DISCUSSION...
AT 19Z...A WELL DEFINED COLD FRONT EXTENDED FROM TEXARKANA TO
HOUSTON TO JUST EAST OF PALACIOS. TEMPERATURES ARE ALMOST 25
DEGREES COOLER BEHIND THE FRONT. THE FRONT WILL CONTINUE TO MOVE
EAST THROUGH THE EVENING AND SHOULD CLEAR ALL OF SE TX BY 23Z (6
PM). AREA HAS REMAINED STRONGLY CAPPED AND SEVERE STORMS DID NOT
DEVELOP AND NONE ARE EXPECTED THIS EVENING. STILL SOME SMALL
CONCERN THAT ELEVATED CONVECTION COULD PRODUCE SOME HAIL AS THE
UPPER TROUGH NEARS LATER TONIGHT. THE UPPER TROUGH WILL PROVIDE
ADDITIONAL LIFT AND SE TX WILL LIE IN A RIGHT REAR QUAD OF THE JET
LATER TONIGHT. THE NAM 12 WHICH HAS PERFORMED RATHER WELL TODAY
ENDS THE RAINFALL BY 06Z WHILE THE GFS/ECMWF AND RAP MODELS ALL
WANT TO REDEVELOP PRECIP MAINLY ALONG AND EAST OF THE US HWY 59
CORRIDOR THROUGH 12Z THURSDAY. FCST SOUNDINGS SHOW SATURATION
BENEATH A STRONG CAP WITH TOTAL TOTALS IN THE LOWER 50S AND PW
VALUES AROUND 1.2 INCHES. FEEL THE POSITION OF THE UPPER JET IS
THE KEY TO WHETHER RAIN REDEVELOPS THIS EVENING AND MODELS DIFFER
A BIT WITH HOW QUICKLY THE UPPER TROUGH PUSHES EAST AND THIS WILL
DETERMINE WHETHER RAIN DEVELOPS OVER LAND OR OVER THE GULF. WATER
VAPOR IMAGERY SUPPORTS THE POSITION OF THE UPPER TROUGH ADVERTISED
BY THE ECMWF. HAVE LEANED TOWARD A BLEND OF HPC...ECMWF...GFS AND
RAP GUIDANCE FOR TONIGHT. RAIN WILL LIKELY BE ENDING AROUND 12Z
THURSDAY AND SKIES WILL QUICKLY CLEAR. TEMPS SHOULD REBOUND NICELY
UNDER FULL SUN DESPITE A VERY COOL START TO THE DAY. RELATIVELY
QUIET WEATHER FRI/SAT AS HIGH PRESSURE DRIFTS ACROSS THE SOUTHERN
PLAINS.
A WELL DEFINED S/WV WILL PUSH ACROSS TEXAS ON SUNDAY. THE GFS IS
QUITE AGGRESSIVE WITH THE MOISTURE RETURN ON SUNDAY. THE ECMWF
FOCUSES MORE OF THE PRECIP OFFSHORE YET IT`S SOLUTION ALSO OFFERS
UP A STRONG S/WV TROUGH MOVING ACROSS THE STATE. THE CANADIAN
SUPPORTS THE WETTER GFS SOLUTION SO WILL ADD POPS FOR SUNDAY. JET
DYNAMICS DON`T LOOK FAVORABLE SO WILL ONLY GO WITH SLIGHT RAIN
CHANCES FOR NOW.
UPPER LEVEL RIDGING OVER THE GULF OF MEXICO WILL AMPLIFY AND
EXPAND INTO SOUTHEAST TEXAS EARLY NEXT WEEK. FCST SOUNDINGS
SUPPORT MAX TEMPS IN THE UPPER 80S. BUMPED MAX TEMPS UP A FEW
DEGREES FOR MON-WED. ANOTHER FRONT EXPECTED TOWARD THE END OF NEXT
WEEK. THE POSITION OF THE UPPER RIDGE FAVORS THE SLOWER ECMWF SO
LEANED TOWARD THE SLOWER FROPA FOR THE END OF NEXT WEEK. 43
&&
.MARINE...
THE PRIMARY NEAR TERM ISSUES WILL BE THE RECENT COASTAL RUN UP AND
THE MODEST CHANCE FOR LINGERING OVERNIGHT PRECIPITATION. CURRENT
WATER LEVELS ARE AROUND A FOOT ABOVE NORMAL PER THIS RECENT NEAR 20
KNOT SOUTHEASTERLY FETCH...A NEAR SUNSET COLD FRONTAL PASSAGE WILL
VEER WINDS AROUND TO NORTHWEST AT SIMILAR MAGNITUDES. VARIOUS HIGHER
RESOLUTION WEATHER FORECAST MODELS ARE INDICATING MORE STEADY
RAINFALL OVER OUR (MORE EASTERN) WATERS TONIGHT AND LASTING THROUGH
SUNRISE THURSDAY. THE HIGHER CHANCE FOR POST-FRONTAL RAIN CAN BE
ATTRIBUTED TO THE FAVORABLE POSITIONING OF THE JET STREAM WITH THE
SLOWER EASTERN-ADVANCEMENT OF THE UPPER LEVEL TROUGH. EARLY THURSDAY
SCA LEVEL OFFSHORE WINDS WILL WEAKEN TO BELOW SCEC BY THE EVENING...BAYS
SHOULD BE BELOW SCEC BY THE EARLY AFTERNOON. 31
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 42 68 46 76 52 / 20 10 0 0 0
HOUSTON (IAH) 47 70 49 77 53 / 50 10 0 0 0
GALVESTON (GLS) 51 72 60 76 63 / 60 20 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...
MATAGORDA.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: MATAGORDA BAY...WATERS FROM FREEPORT TO THE
MATAGORDA SHIP CHANNEL 20 NM TO 60 NM...WATERS FROM
FREEPORT TO THE MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS
FROM HIGH ISLAND TO FREEPORT 20 TO 60 NM...WATERS FROM HIGH
ISLAND TO FREEPORT OUT 20 NM.
SMALL CRAFT ADVISORY FROM 1 AM TO 7 AM CDT THURSDAY FOR THE
FOLLOWING ZONES: GALVESTON BAY.
SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 1 AM CDT THURSDAY FOR
THE FOLLOWING ZONES: GALVESTON BAY.
&&
$$
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1259 PM CDT WED APR 10 2013
.DISCUSSION...
18Z AVIATION UPDATE BELOW.
&&
.AVIATION...
TIMING THE FRONTAL PASSAGE AND DETERMINING ITS ASSOCIATED CONVECTION
WILL BE THE MAIN TASK THIS AFTERNOON. ONGOING OBS INDICATE THAT
AN AGGRESSIVE COLD FRONT IS ADVANCING SOUTHEAST AT AROUND 10 KNOTS
AND WAS LOCATED ALONG A COLUMBUS TO HUNTSVILLE TO CROCKETT LINE
DURING THE NOON HOUR. AT ITS CURRENT PACE...IT WILL PASS THROUGH
THE CITY HUBS AT BETWEEN 19-21Z...COASTAL WINDS VEER AROUND TO
NORTHWEST AT AROUND 22-23Z. LIGHT RAIN/SHOWERS JUST AHEAD OF THE
BOUNDARY WILL TRANSITION TO PERIODS OF HEAVIER (VERY SHORT-LIVED)
RAIN AND A FEW ELEVATED THUNDERSTORMS ARE POSSIBLE. CEILINGS WILL
REMAIN MVFR...WITH THE EXCEPTION OF BRIEF IFR WITHIN RAIN EPISODES.
ONCE THE FRONT PASSES SOUTH OF THE TERMINAL...NW WINDS WILL PRIMARILY
BECOME 15G25KT. MOISTURE TRAPPED UNDERNEATH THE FRONTAL INVERSION
WILL KEEP EITHER A LOW-END MVFR OR UPPER-END IFR OVERCAST DECK IN
PLACE THROUGH AROUND 11/14-16Z. MORE MODERATE NW`ERLIES SHOULD PRECLUDE
THE MENTION OF LIFR DECKS OR FOG. AS THE UPPER TROUGH AXIS SWINGS
ACROSS NE TEXAS TOMORROW MORNING...THERE REMAINS A CHANCE FOR LINGERING
NEAR-COASTAL PRECIPITATION THROUGH THE EARLY THURSDAY MORNING HOURS.
31
&&
.PREV DISCUSSION... /ISSUED 1126 AM CDT WED APR 10 2013/
UPDATE...
UPDATED MARINE HAZARDS BELOW.
MARINE...
THIS MORNING`S UPDATED MARINE HAZARD GRIDS ARE ALIGNED TO BETTER
CAPTURE THE TIMING OF TODAY`S FRONTAL PASSAGE. THE FRONT IS
FORECAST TO PASS ACROSS THE WESTERN BAYS AND OFFSHORE WATERS
DURING MID-AFTERNOON...BE ACROSS OUR MORE EASTERN WATERS FROM
LATE AFTERNOON INTO THE EARLY EVENING HOURS. MODERATE TO STRONG
NORTHWESTERLIES WILL FOLLOW IN THE FRONT`S WAKE. LATE DAY RAIN
WITH ISOLATED THUNDERSTORMS WILL LIKELY OCCUR IN THE VICINITY OF
THE APPROACHING FRONTAL BOUNDARY. THIS PRECIPITATION MAY LINGER ON
PAST MIDNIGHT THURSDAY. 31
PREV DISCUSSION... /ISSUED 1011 AM CDT WED APR 10 2013/
UPDATE...
SEE MORNING UPDATE.
DISCUSSION...
FINDING THE COLD FRONT IS NO PROBLEM THIS MORNING AS 10 AM TEMPS
ARE CURRENTLY 48 DEGREES AT CALDWELL AND 30 MILES SOUTH IN
BRENHAM...THE TEMP IS CURRENTLY 78 DEGREES. SHRA/TSRA HAVE
STRUGGLED TO INITIATE AS A CAPPING INVERSION REMAINS VERY STRONG.
SOUNDING FROM KCLL SHOWS A STRONG CAP IN PLACE AND CONVECTIVE
TEMPS NEED TO REACH 90 WHICH LOOKS UNLIKELY CONSIDERING THICK
CLOUD COVER. 300 MB WINDS SHOW A NICE SPLIT WITH STRONG UPPER
DIVERGENCE. PW VALUES ARE APPROACHING 1.6 INCHES OVER THE CENTRAL
AND COASTAL ZONES FEEL SHRA WILL INCREASE BUT CAPPING SHOULD LIMIT
SEVERE POTENTIAL TODAY TO MAINLY THE NORTHEAST QUARTER OF THE CWA
LATER THIS AFTERNOON. FEEL MOST OF THE RAIN WILL BE POST-FRONTAL
ASSOCIATED MORE WITH THE LIFT WITH THE UPPER TROUGH AND AN UPPER
LEVEL DISTURBANCE MOVING TOWARD SE TX FROM NORTHERN MEXICO.
KHGX-88D IS BEGINNING TO SHOW SOME LIGHT RAIN OVER THE WESTERN
HALF OF THE REGION. THE FRONT WILL CONTINUE TO MARCH EASTWARD
TODAY AND MAX TEMPS HAVE ALREADY OCCURRED OUT WEST AND TEMPS WILL
LIKELY BE FALLING OVER THE EASTERN HALF OF THE CWA THIS AFTERNOON.
THE RAP INITIALIZED FAIRLY WELL AND WILL LEAN TOWARD A NAM 12/RAP
BLEND FOR WIND SHIFT...POPS AND AFTERNOON TEMPS. THE FRONT SHOULD
MOVE THROUGH HARRIS COUNTY BETWEEN 19-21Z. MADE QUITE A FEW
MODIFICATIONS TO THE GRIDS...PARTICULARLY WITH HOURLY TEMPS...DEW
PTS...SKY GRIDS...POPS AND WEATHER. NEW ZONES OUT BY 1030 AM. 43
PREV DISCUSSION... /ISSUED 750 AM CDT WED APR 10 2013/
AVIATION...
CIGS OF 1100 TO 2500 MVFR CIGS THIS MORNING WITH SOUTH WINDS. COLD
FRONT HAS MOVED THROUGH ACT-EWX LINE NEARLY IN LHB. UPDATED TAFS
AGAIN FOR EVEN FASTER FRONTAL PASSAGE BY ABOUT AN HOUR. ALONG THE
FRONT EXPECT FREQUENT SHOWERS AND ISOLATED THUNDERSTORMS...STRONG
THUNDERSTORMS A GOOD BET WITH WIND GUSTS OF 30 TO 35+ KNOTS.
SHOWERS AND THUNDERSTORMS LINGERING AFTER THE FRONTAL PASSAGE.
UPDATED FRONTAL TIMING +/- AN HOUR CLL AROUND 1430Z...UTS
1545Z...CXO/IAH 1730-1830Z...HOU 19Z...GLS 21Z. LIGHT SHOWERS
SHOULD CONTINUE FOR 3 TO 4 HOURS AFTER FROPA. NNW WINDS 13-20KTS
IN THE WAKE OF THE FRONT. ALSO ADDED IN PROB30 FOR SHOWERS AFTER
08Z/THU MORNING AS TROUGH NEARS AND S/W TRACKS THROUGH THE AREA.
45
PREV DISCUSSION... /ISSUED 508 AM CDT WED APR 10 2013/
DISCUSSION...
NOT A LOT OF CHANGES WITH THE SHORT-TERM PART OF THE FCST AS THE
INGREDIENTS FOR STRONG/SEVERE STORMS CONTINUE TO FALL INTO PLACE
FOR TODAY ACROSS SE TX.
WHILE THERE ARE STILL CONCERNS WITH WHETHER OR NOT THE CAP WILL/
CAN BE BROKEN...HAVE OPTED TO REMAIN ON THE PESSIMISTIC SIDE FOR
TODAY/TONIGHT. VERY STRONG DYNAMICS AT THE SFC (WITH THE SHARPLY
DEFINED COLD FRONT)...THE BROAD BUT VERY PRONOUNCED SPLITTING OF
THE UPPER JET AND THE TIMING OF SAID COLD FRONT SHOULD BE ENOUGH
TO BREAK THE CAP AS THESE SYSTEMS CONVERGE OVER SE TX THIS AFTN.
WARM MOIST UNSTABLE AIR ACROSS THE REGION ALONG WITH THE PROGGED
S/WV DO INDICATE AN ACTIVE AFTN/EVE FOR THE CWA.
POST EVENT FCST PROVING TO BE A BUT PROBLEMATIC AS MODELS REMAIN
KIND OF INSISTENT WITH THE RAPID APPROACH/PASSAGE OF A SHORTWAVE
SUN/MON. WILL LIKELY KEEP POPS OUT FOR NOW AS MOISTURE IS EXPECT-
ED GIVEN THE LIMITED RETURN OF RETURN FLOW. THIS DRY FCST SHOULD
PERSIST INTO THE EARLY NEXT WEEK. THE NEXT CHANCES OF PCPN (WITH
ANOTHER COLD FRONT) LOOKING A BIT IFFY GIVEN THE TRENDS WITH THE
LATEST EXTENDED GUIDANCE. 41
MARINE...
SEAS BUILT TO 8 TO 10 FEET EARLIER WITH THE SHOWERS AND
THUNDERSTORMS. WINDS HAVE RELAXED SLIGHTLY NEARSHORE BUT REMAIN
STRONG WELL OFFSHORE. THE SOUTHERLY FLOW WILL CONTINUE TODAY UNTIL A
COLD FRONT NEARS AND WINDS DROP OFF AND THEN MOVES OFF THE COAST
TURNING WINDS NORTH AT 20 TO 25 KNOTS. EXPECT THE FRONT OFF THE
COAST NEAR MATAGORDA BAY FIRST AT AROUND 2-3 PM GALVESTON BAY AROUND
4 TO 5 PM. STRONG TO SEVERE THUNDERSTORMS TODAY WILL BE POSSIBLE
WITH THE PRIMARY THREAT WINDS. WINDS IN THE WAKE OF THE FRONT SLOWLY
SUBSIDE THURSDAY AND BECOME EASTERLY THROUGH FRIDAY THEN SOUTHEAST
TO SOUTH FLOW BECOMES RE-ESTABLISHED AS HIGH SLIDES AWAY. WINDS THIS
WEEKEND MAY REACH SCEC.
TIDES WILL PEAK THIS MORNING AT 1.5 TO 2 FEET ABOVE NORMAL WITH
ABUNDANT RUNUP ON THE BEACHES. RIP CURRENTS THREAT ALSO HIGH TODAY
ENDING AFTER FROPA.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 43 67 45 75 51 / 30 20 0 0 0
HOUSTON (IAH) 48 70 46 76 51 / 40 20 0 0 0
GALVESTON (GLS) 52 72 57 75 62 / 50 30 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...
MATAGORDA.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: MATAGORDA BAY.
SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 1 PM CDT THIS
AFTERNOON FOR THE FOLLOWING ZONES: MATAGORDA BAY.
SMALL CRAFT ADVISORY FROM 1 AM TO 7 AM CDT THURSDAY FOR THE
FOLLOWING ZONES: GALVESTON BAY.
SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH LATE TONIGHT FOR THE
FOLLOWING ZONES: GALVESTON BAY.
SMALL CRAFT ADVISORY UNTIL 7 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20
TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...31
AVIATION/MARINE...43
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1126 AM CDT WED APR 10 2013
.UPDATE...
UPDATED MARINE HAZARDS BELOW.
&&
.MARINE...
THIS MORNING`S UPDATED MARINE HAZARD GRIDS ARE ALIGNED TO BETTER
CAPTURE THE TIMING OF TODAY`S FRONTAL PASSAGE. THE FRONT IS
FORECAST TO PASS ACROSS THE WESTERN BAYS AND OFFSHORE WATERS
DURING MID-AFTERNOON...BE ACROSS OUR MORE EASTERN WATERS FROM
LATE AFTERNOON INTO THE EARLY EVENING HOURS. MODERATE TO STRONG
NORTHWESTERLIES WILL FOLLOW IN THE FRONT`S WAKE. LATE DAY RAIN
WITH ISOLATED THUNDERSTORMS WILL LIKELY OCCUR IN THE VICINITY OF
THE APPROACHING FRONTAL BOUNDARY. THIS PRECIPITATION MAY LINGER ON
PAST MIDNIGHT THURSDAY. 31
&&
.PREV DISCUSSION... /ISSUED 1011 AM CDT WED APR 10 2013/
UPDATE...
SEE MORNING UPDATE.
DISCUSSION...
FINDING THE COLD FRONT IS NO PROBLEM THIS MORNING AS 10 AM TEMPS
ARE CURRENTLY 48 DEGREES AT CALDWELL AND 30 MILES SOUTH IN
BRENHAM...THE TEMP IS CURRENTLY 78 DEGREES. SHRA/TSRA HAVE
STRUGGLED TO INITIATE AS A CAPPING INVERSION REMAINS VERY STRONG.
SOUNDING FROM KCLL SHOWS A STRONG CAP IN PLACE AND CONVECTIVE
TEMPS NEED TO REACH 90 WHICH LOOKS UNLIKELY CONSIDERING THICK
CLOUD COVER. 300 MB WINDS SHOW A NICE SPLIT WITH STRONG UPPER
DIVERGENCE. PW VALUES ARE APPROACHING 1.6 INCHES OVER THE CENTRAL
AND COASTAL ZONES FEEL SHRA WILL INCREASE BUT CAPPING SHOULD LIMIT
SEVERE POTENTIAL TODAY TO MAINLY THE NORTHEAST QUARTER OF THE CWA
LATER THIS AFTERNOON. FEEL MOST OF THE RAIN WILL BE POST-FRONTAL
ASSOCIATED MORE WITH THE LIFT WITH THE UPPER TROUGH AND AN UPPER
LEVEL DISTURBANCE MOVING TOWARD SE TX FROM NORTHERN MEXICO.
KHGX-88D IS BEGINNING TO SHOW SOME LIGHT RAIN OVER THE WESTERN
HALF OF THE REGION. THE FRONT WILL CONTINUE TO MARCH EASTWARD
TODAY AND MAX TEMPS HAVE ALREADY OCCURRED OUT WEST AND TEMPS WILL
LIKELY BE FALLING OVER THE EASTERN HALF OF THE CWA THIS AFTERNOON.
THE RAP INITIALIZED FAIRLY WELL AND WILL LEAN TOWARD A NAM 12/RAP
BLEND FOR WIND SHIFT...POPS AND AFTERNOON TEMPS. THE FRONT SHOULD
MOVE THROUGH HARRIS COUNTY BETWEEN 19-21Z. MADE QUITE A FEW
MODIFICATIONS TO THE GRIDS...PARTICULARLY WITH HOURLY TEMPS...DEW
PTS...SKY GRIDS...POPS AND WEATHER. NEW ZONES OUT BY 1030 AM. 43
PREV DISCUSSION... /ISSUED 750 AM CDT WED APR 10 2013/
AVIATION...
CIGS OF 1100 TO 2500 MVFR CIGS THIS MORNING WITH SOUTH WINDS. COLD
FRONT HAS MOVED THROUGH ACT-EWX LINE NEARLY IN LHB. UPDATED TAFS
AGAIN FOR EVEN FASTER FRONTAL PASSAGE BY ABOUT AN HOUR. ALONG THE
FRONT EXPECT FREQUENT SHOWERS AND ISOLATED THUNDERSTORMS...STRONG
THUNDERSTORMS A GOOD BET WITH WIND GUSTS OF 30 TO 35+ KNOTS.
SHOWERS AND THUNDERSTORMS LINGERING AFTER THE FRONTAL PASSAGE.
UPDATED FRONTAL TIMING +/- AN HOUR CLL AROUND 1430Z...UTS
1545Z...CXO/IAH 1730-1830Z...HOU 19Z...GLS 21Z. LIGHT SHOWERS
SHOULD CONTINUE FOR 3 TO 4 HOURS AFTER FROPA. NNW WINDS 13-20KTS
IN THE WAKE OF THE FRONT. ALSO ADDED IN PROB30 FOR SHOWERS AFTER
08Z/THU MORNING AS TROUGH NEARS AND S/W TRACKS THROUGH THE AREA.
45
PREV DISCUSSION... /ISSUED 508 AM CDT WED APR 10 2013/
DISCUSSION...
NOT A LOT OF CHANGES WITH THE SHORT-TERM PART OF THE FCST AS THE
INGREDIENTS FOR STRONG/SEVERE STORMS CONTINUE TO FALL INTO PLACE
FOR TODAY ACROSS SE TX.
WHILE THERE ARE STILL CONCERNS WITH WHETHER OR NOT THE CAP WILL/
CAN BE BROKEN...HAVE OPTED TO REMAIN ON THE PESSIMISTIC SIDE FOR
TODAY/TONIGHT. VERY STRONG DYNAMICS AT THE SFC (WITH THE SHARPLY
DEFINED COLD FRONT)...THE BROAD BUT VERY PRONOUNCED SPLITTING OF
THE UPPER JET AND THE TIMING OF SAID COLD FRONT SHOULD BE ENOUGH
TO BREAK THE CAP AS THESE SYSTEMS CONVERGE OVER SE TX THIS AFTN.
WARM MOIST UNSTABLE AIR ACROSS THE REGION ALONG WITH THE PROGGED
S/WV DO INDICATE AN ACTIVE AFTN/EVE FOR THE CWA.
POST EVENT FCST PROVING TO BE A BUT PROBLEMATIC AS MODELS REMAIN
KIND OF INSISTENT WITH THE RAPID APPROACH/PASSAGE OF A SHORTWAVE
SUN/MON. WILL LIKELY KEEP POPS OUT FOR NOW AS MOISTURE IS EXPECT-
ED GIVEN THE LIMITED RETURN OF RETURN FLOW. THIS DRY FCST SHOULD
PERSIST INTO THE EARLY NEXT WEEK. THE NEXT CHANCES OF PCPN (WITH
ANOTHER COLD FRONT) LOOKING A BIT IFFY GIVEN THE TRENDS WITH THE
LATEST EXTENDED GUIDANCE. 41
MARINE...
SEAS BUILT TO 8 TO 10 FEET EARLIER WITH THE SHOWERS AND
THUNDERSTORMS. WINDS HAVE RELAXED SLIGHTLY NEARSHORE BUT REMAIN
STRONG WELL OFFSHORE. THE SOUTHERLY FLOW WILL CONTINUE TODAY UNTIL A
COLD FRONT NEARS AND WINDS DROP OFF AND THEN MOVES OFF THE COAST
TURNING WINDS NORTH AT 20 TO 25 KNOTS. EXPECT THE FRONT OFF THE
COAST NEAR MATAGORDA BAY FIRST AT AROUND 2-3 PM GALVESTON BAY AROUND
4 TO 5 PM. STRONG TO SEVERE THUNDERSTORMS TODAY WILL BE POSSIBLE
WITH THE PRIMARY THREAT WINDS. WINDS IN THE WAKE OF THE FRONT SLOWLY
SUBSIDE THURSDAY AND BECOME EASTERLY THROUGH FRIDAY THEN SOUTHEAST
TO SOUTH FLOW BECOMES RE-ESTABLISHED AS HIGH SLIDES AWAY. WINDS THIS
WEEKEND MAY REACH SCEC.
TIDES WILL PEAK THIS MORNING AT 1.5 TO 2 FEET ABOVE NORMAL WITH
ABUNDANT RUNUP ON THE BEACHES. RIP CURRENTS THREAT ALSO HIGH TODAY
ENDING AFTER FROPA.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 75 43 67 45 75 / 60 30 20 0 0
HOUSTON (IAH) 79 48 70 46 76 / 60 40 20 0 0
GALVESTON (GLS) 78 52 72 57 75 / 40 50 30 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...
MATAGORDA.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: MATAGORDA BAY.
SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 1 PM CDT THIS
AFTERNOON FOR THE FOLLOWING ZONES: MATAGORDA BAY.
SMALL CRAFT ADVISORY FROM 1 AM TO 7 AM CDT THURSDAY FOR THE
FOLLOWING ZONES: GALVESTON BAY.
SMALL CRAFT SHOULD EXERCISE CAUTION THROUGH LATE TONIGHT FOR THE
FOLLOWING ZONES: GALVESTON BAY.
SMALL CRAFT ADVISORY UNTIL 7 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20
TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
DISCUSSION...43
AVIATION/MARINE...31
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1011 AM CDT WED APR 10 2013
.UPDATE...
SEE MORNING UPDATE.
&&
.DISCUSSION...
FINDING THE COLD FRONT IS NO PROBLEM THIS MORNING AS 10 AM TEMPS
ARE CURRENTLY 48 DEGREES AT CALDWELL AND 30 MILES SOUTH IN
BRENHAM...THE TEMP IS CURRENTLY 78 DEGREES. SHRA/TSRA HAVE
STRUGGLED TO INIITIATE AS A CAPPING INVERSION REMAINS VERY STRONG.
SOUNDING FROM KCLL SHOWS A STRONG CAP IN PLACE AND CONVECTIVE
TEMPS NEED TO REACH 90 WHICH LOOKS UNLIKELY CONSIDERING THICK
CLOUD COVER. 300 MB WINDS SHOW A NICE SPLIT WITH STRONG UPPER
DIVERGENCE. PW VALUES ARE APPROACHING 1.6 INCHES OVER THE CENTRAL
AND COASTAL ZONES FEEL SHRA WILL INCREASE BUT CAPPING SHOULD LIMIT
SEVERE POTENTIAL TODAY TO MAINLY THE NORTHEAST QUARTER OF THE CWA
LATER THIS AFTERNOON. FEEL MOST OF THE RAIN WILL BE POST-FRONTAL
ASSOCIATED MORE WITH THE LIFT WITH THE UPPER TROUGH AND AN UPPER
LEVEL DISTURBANCE MOVING TOWARD SE TX FROM NORTHERN MEXICO.
KHGX-88D IS BEGINNING TO SHOW SOME LIGHT RAIN OVER THE WESTERN
HALF OF THE REGION. THE FRONT WILL CONTINUE TO MARCH EASTWARD
TODAY AND MAX TEMPS HAVE ALREADY OCCURRED OUT WEST AND TEMPS WILL
LIKELY BE FALLING OVER THE EASTERN HALF OF THE CWA THIS AFTERNOON.
THE RAP INITIALIZED FAIRLY WELL AND WILL LEAN TOWARD A NAM 12/RAP
BLEND FOR WIND SHIFT...POPS AND AFTERNOON TEMPS. THE FRONT SHOULD
MOVE THROUGH HARRIS COUNTY BETWEEN 19-21Z. MADE QUITE A FEW
MODIFICATIONS TO THE GRIDS...PARTICULARLY WITH HOURLY TEMPS...DEW
PTS...SKY GRIDS...POPS AND WEATHER. NEW ZONES OUT BY 1030 AM. 43
&&
.PREV DISCUSSION... /ISSUED 750 AM CDT WED APR 10 2013/
AVIATION...
CIGS OF 1100 TO 2500 MVFR CIGS THIS MORNING WITH SOUTH WINDS. COLD
FRONT HAS MOVED THROUGH ACT-EWX LINE NEARLY IN LHB. UPDATED TAFS
AGAIN FOR EVEN FASTER FRONTAL PASSAGE BY ABOUT AN HOUR. ALONG THE
FRONT EXPECT FREQUENT SHOWERS AND ISOLATED THUNDERSTORMS...STRONG
THUNDERSTORMS A GOOD BET WITH WIND GUSTS OF 30 TO 35+ KNOTS.
SHOWERS AND THUNDERSTORMS LINGERING AFTER THE FRONTAL PASSAGE.
UPDATED FRONTAL TIMING +/- AN HOUR CLL AROUND 1430Z...UTS
1545Z...CXO/IAH 1730-1830Z...HOU 19Z...GLS 21Z. LIGHT SHOWERS
SHOULD CONTINUE FOR 3 TO 4 HOURS AFTER FROPA. NNW WINDS 13-20KTS
IN THE WAKE OF THE FRONT. ALSO ADDED IN PROB30 FOR SHOWERS AFTER
08Z/THU MORNING AS TROUGH NEARS AND S/W TRACKS THROUGH THE AREA.
45
PREV DISCUSSION... /ISSUED 508 AM CDT WED APR 10 2013/
DISCUSSION...
NOT A LOT OF CHANGES WITH THE SHORT-TERM PART OF THE FCST AS THE
INGREDIENTS FOR STRONG/SEVERE STORMS CONTINUE TO FALL INTO PLACE
FOR TODAY ACROSS SE TX.
WHILE THERE ARE STILL CONCERNS WITH WHETHER OR NOT THE CAP WILL/
CAN BE BROKEN...HAVE OPTED TO REMAIN ON THE PESSIMISTIC SIDE FOR
TODAY/TONIGHT. VERY STRONG DYNAMICS AT THE SFC (WITH THE SHARPLY
DEFINED COLD FRONT)...THE BROAD BUT VERY PRONOUNCED SPLITTING OF
THE UPPER JET AND THE TIMING OF SAID COLD FRONT SHOULD BE ENOUGH
TO BREAK THE CAP AS THESE SYSTEMS CONVERGE OVER SE TX THIS AFTN.
WARM MOIST UNSTABLE AIR ACROSS THE REGION ALONG WITH THE PROGGED
S/WV DO INDICATE AN ACTIVE AFTN/EVE FOR THE CWA.
POST EVENT FCST PROVING TO BE A BUT PROBLEMATIC AS MODELS REMAIN
KIND OF INSISTENT WITH THE RAPID APPROACH/PASSAGE OF A SHORTWAVE
SUN/MON. WILL LIKELY KEEP POPS OUT FOR NOW AS MOISTURE IS EXPECT-
ED GIVEN THE LIMITED RETURN OF RETURN FLOW. THIS DRY FCST SHOULD
PERSIST INTO THE EARLY NEXT WEEK. THE NEXT CHANCES OF PCPN (WITH
ANOTHER COLD FRONT) LOOKING A BIT IFFY GIVEN THE TRENDS WITH THE
LATEST EXTENDED GUIDANCE. 41
MARINE...
SEAS BUILT TO 8 TO 10 FEET EARLIER WITH THE SHOWERS AND
THUNDERSTORMS. WINDS HAVE RELAXED SLIGHTLY NEARSHORE BUT REMAIN
STRONG WELL OFFSHORE. THE SOUTHERLY FLOW WILL CONTINUE TODAY UNTIL A
COLD FRONT NEARS AND WINDS DROP OFF AND THEN MOVES OFF THE COAST
TURNING WINDS NORTH AT 20 TO 25 KNOTS. EXPECT THE FRONT OFF THE
COAST NEAR MATAGORDA BAY FIRST AT AROUND 2-3 PM GALVESTON BAY AROUND
4 TO 5 PM. STRONG TO SEVERE THUNDERSTORMS TODAY WILL BE POSSIBLE
WITH THE PRIMARY THREAT WINDS. WINDS IN THE WAKE OF THE FRONT SLOWLY
SUBSIDE THURSDAY AND BECOME EASTERLY THROUGH FRIDAY THEN SOUTHEAST
TO SOUTH FLOW BECOMES RE-ESTABLISHED AS HIGH SLIDES AWAY. WINDS THIS
WEEKEND MAY REACH SCEC.
TIDES WILL PEAK THIS MORNING AT 1.5 TO 2 FEET ABOVE NORMAL WITH
ABUNDANT RUNUP ON THE BEACHES. RIP CURRENTS THREAT ALSO HIGH TODAY
ENDING AFTER FROPA.
45
&&
.PRELIMINARY POINT TEMPS/POPS...
COLLEGE STATION (CLL) 65 43 67 45 75 / 60 30 20 0 0
HOUSTON (IAH) 79 48 70 46 76 / 60 40 20 0 0
GALVESTON (GLS) 75 52 72 57 75 / 40 50 30 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK UNTIL 7 PM CDT THIS EVENING FOR THE
FOLLOWING ZONES: BRAZORIA...CHAMBERS...GALVESTON...
MATAGORDA.
GM...SMALL CRAFT ADVISORY FROM 2 PM THIS AFTERNOON TO 7 AM CDT
THURSDAY FOR THE FOLLOWING ZONES: GALVESTON BAY...MATAGORDA
BAY.
SMALL CRAFT SHOULD EXERCISE CAUTION UNTIL 2 PM CDT THIS
AFTERNOON FOR THE FOLLOWING ZONES: GALVESTON BAY...
MATAGORDA BAY.
SMALL CRAFT ADVISORY UNTIL 7 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: WATERS FROM FREEPORT TO THE MATAGORDA SHIP CHANNEL
20 NM TO 60 NM...WATERS FROM FREEPORT TO THE MATAGORDA SHIP
CHANNEL OUT 20 NM...WATERS FROM HIGH ISLAND TO FREEPORT 20
TO 60 NM...WATERS FROM HIGH ISLAND TO FREEPORT OUT 20 NM.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1223 AM CDT WED APR 10 2013
.AVIATION...
THE COLD FRONT WAS JUST TO THE NORTHWEST OF THE METROPLEX TAF SITES
AS OF MIDNIGHT AND SHOULD MOVE THROUGH ALL BUT DAL BY TAF ISSUANCE
TIME. FROPA AT WACO WILL BE AROUND 08Z. EXPECT CEILINGS TO LOWER
TO MVFR BEHIND THE COLD FRONT AND REMAIN BETWEEN 1000 AND 2000 FT
UNTIL LATE AFTERNOON. THE BEST WINDOW FOR SHOWERS AND
THUNDERSTORMS WILL BE BETWEEN 09Z AND 16Z. CEILINGS WILL LIFT TO
VFR BEFORE 00Z AND SHOULD SCATTER OUT BEFORE 05Z.
THE WIND WILL TURN TO THE NORTHWEST AND INCREASE BETWEEN 15 AND 20
KNOTS WITH THE PASSAGE OF THE FRONT. THE WIND WILL BECOME MORE
NORTHERLY AROUND SUNRISE AT SPEEDS BETWEEN 17 AND 21 KNOTS
SUSTAINED. NORTH WINDS SHOULD BEGIN TO DECREASE TOWARD SUNSET.
79
&&
.UPDATE...
ONLY CHANGES MADE TO THE PREVIOUS FORECAST WERE TO ACCOUNT FOR
HOURLY TRENDS ASSOCIATED WITH THE CURRENT POSITION OF THE COLD
FRONT...AND TO SLOW DOWN THE TIMING OF THE ONSET OF SHOWERS AND
THUNDERSTORMS ACROSS NORTH AND CENTRAL TEXAS TONIGHT AND INTO
WEDNESDAY.
03Z WATER VAPOR IMAGERY INDICATED THAT THE UPPER LOW HAD NOT MOVED
MUCH THIS EVENING AND WAS ESSENTIALLY STATIONARY NEAR THE FOUR
CORNERS REGION. A SHORTWAVE TROUGH EMBEDDED IN THE FLOW AROUND THE
UPPER LOW WAS EVIDENT JUST SOUTHWEST OF EL PASO...MOVING
NORTHEAST. THE LARGE SCALE FORCING FOR ASCENT ASSOCIATED WITH THIS
TROUGH WAS SPREADING OVER WEST TX AND WAS WELL CORRELATED WITH THE
NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING FROM CHILDRESS TO
SWEETWATER AT 04Z. THIS AREA OF SHOWERS AND STORMS ALSO APPEARS TO
BE WELL-CORRELATED WITH AN H850 FRONT THAT WAS LOCATED FROM
OKLAHOMA CITY TO SAN ANGELO ACCORDING TO REGIONAL VAD WIND
PROFILES. THE UPPER LEVEL FORCING FOR ASCENT AND THE H850 FRONT
WILL TRACK SOUTHEAST TONIGHT...AND SHOULD REMAIN ASSOCIATED WITH
NUMEROUS SHOWERS AND THUNDERSTORMS AS THESE FEATURES MOVE OVER
NORTH TX.
TRACKING THE H850 FRONT IN THE RAP AND NAM INDICATES THAT WE WILL
SEE WIDESPREAD RAIN SHOWERS AND THUNDERSTORMS WEST OF INTERSTATE
35 FROM MIDNIGHT THROUGH SUNRISE/12Z. WENT AHEAD AND PLACED 90
POPS FOR THESE AREAS AS A RESULT. THUNDERSTORMS WILL BE ELEVATED
WELL BEHIND THE SURFACE COLD FRONT LIMITING THE POTENTIAL FOR
DAMAGING WINDS AND ELIMINATING THE THREAT FOR TORNADOES
OVERNIGHT. HOWEVER THE FWD 00Z SOUNDING OBSERVED A LAYER OF STEEP
LAPSE RATES FROM 700 TO 300 MB INDICATING THAT THERE WILL CONTINUE
TO BE A THREAT FOR ELEVATED ORGANIZED CONVECTION CAPABLE OF
PRODUCING SEVERE HAIL TONIGHT THROUGH WEDNESDAY MORNING. UPSTREAM
CONVECTION HAS BEEN LARGELY MULTICELLULAR IN NATURE...HOWEVER RAP
FORECAST SOUNDINGS INDICATE OVER 1000 J/KG OF MUCAPE FOR AIR
PARCELS LIFTED IN THE H850 TO H750 LAYER. EFFECTIVE BULK SHEAR FOR
AIR LIFTED AT THIS LEVEL IS STILL FORECAST TO BE AROUND 50 KTS
WHICH IS SUPPORTIVE OF A SUPER CELLULAR STORM MODE...ALBEIT
ELEVATED SUPERCELLS.
AT ANY RATE...THINK THE THREAT FOR SEVERE HAIL WILL PERSIST
THROUGH THE OVERNIGHT HOURS INTO WEDNESDAY MORNING. HAIL UP TO
GOLFBALL SIZED CANNOT BE RULED OUT WITH ANY ELEVATED SUPERCELL.
THE EFFECTIVE LAYER HODOGRAPH /ESSENTIALLY THE 2.5 KM TO 6 KM
LAYER/ IS STRAIGHT LINE IN NATURE INDICATING A SHEAR PROFILE
WEAKLY VEERING WITH HEIGHT BUT DOMINATED BY SPEED SHEAR. IF
SUPERCELLS ARE REALIZED...THIS TYPE OF HODOGRAPH DOES SUPPORT
SPLITTING STORM STRUCTURES AND THE RIGHT OR LEFT MOVER COULD
REASONABLY EXIST FOR NEARLY THE SAME AMOUNT OF TIME. THIS DOESNT
CHANGE THE THREAT AT ALL AS BOTH STORMS WILL BE CAPABLE OF
PRODUCING MAINLY SEVERE HAIL...BUT IT IS SOMETHING WE WILL WATCH
FOR OVERNIGHT AS SPLITTING SUPERCELLS WILL EXHIBIT STORM MOTIONS
DEVIANT FROM THE MEAN UPPER FLOW. ANY TRAINING OF STORMS MAY LEAD
TO LOCALLY HEAVY RAINFALL AND FLOODING HOWEVER THIS IS NOT
EXPECTED TO BE A WIDESPREAD THREAT AT THIS TIME.
CONSIDERED ISSUING A WIND ADVISORY FOR THE STRONG UPSTREAM WINDS
BEHIND THE COLD FRONT...HOWEVER WILL HOLD OFF FOR NOW AS THE
STRONGEST WINDS APPEAR TO BE CONTAINED IN THE DEEPER COLD AIR MASS
LOCATED IN WESTERN OK AND THE TX PANHANDLE WHERE WINTRY WEATHER IS
ACCOMPANYING THE ONGOING THUNDERSTORM ACTIVITY. WE ARE NOT
ANTICIPATING ANY FREEZING TEMPERATURES ACROSS NORTH TX WHEN THE
WIDESPREAD RAIN SHOWERS AND STORMS BUILD IN...BUT WE WILL WATCH
TEMPERATURES CLOSELY THROUGHOUT THE OVERNIGHT HOURS...ESPECIALLY
NORTHWEST OF THE DFW METROPLEX.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 324 PM CDT TUE APR 9 2013/
OVERALL THINKING REGARDING THE SEVERE WEATHER POTENTIAL FOR THE
NEXT 24 HOURS HAS NOT CHANGED. THE BIGGEST CHANGE IS THAT THE COLD
FRONT IS RAPIDLY MOVING THROUGH NORTHWEST TEXAS AND SOUTHWEST
OKLAHOMA AT THIS TIME AND IS STARTING TO OVERTAKE THE DRYLINE JUST
WEST OF VERNON. THE FRONT WILL CONTINUE RACING SOUTHEAST THIS
EVENING AND THE CHANCE FOR SEVERE STORMS DEVELOPING ALONG THE
DRYLINE IS QUICKLY DIMINISHING. HOWEVER...THE CAP HAS WEAKENED
NEAR AND IMMEDIATELY AHEAD OF THE FRONT. LOCAL SEVERE WEATHER
PARAMETERS ALSO INDICATE THE CAP HAS SUFFICIENTLY WEAKENED ALONG
THE DRYLINE OVER OUR WESTERN COUNTIES AND SOME SEVERE STORMS WILL
BE POSSIBLE ALONG THE COLD FRONT AS IT MOVES INTO OUR AREA THIS
EVENING. MOST OF THE STORMS THAT DEVELOP ALONG THE FRONT WILL BE
QUICKLY UNDERCUT BY THE COLD ARCTIC AIR BEHIND THE FRONT AND
BECOME ELEVATED. THUS...THE MAIN THREAT WITH THESE STORMS WILL BE
HAIL. THE THREAT FOR SEVERE STORMS WILL CONTINUE ALONG THE FRONT
OVERNIGHT AND WE WILL LIKELY SEE AN INCREASE IN STORM COVERAGE
ALONG AND BEHIND THE FRONT AS THE LOW LEVEL JET INCREASES AND
UPPER LEVEL LIFT INCREASES OVER THE REGION. HAIL WILL CONTINUE TO
BE THE MAIN THREAT OVERNIGHT.
LATEST TRACKING OF THE FRONT HAS IT REACHING OUR NORTHWEST
COUNTIES BETWEEN 00-01Z/7-8 PM CDT. HAVE ADJUSTED THE WINDS AND
POPS IN THE NEAR-TERM TO REFLECT THIS FASTER TIMING. DESPITE
HIGH POPS ACROSS THE REGION OVERNIGHT...COVERAGE MAY LIKELY BE
SPARSE AT FIRST BUT THEN INCREASE AS THE NIGHT PROGRESSES. BY
MIDDAY WEDNESDAY...THE FRONT WILL BE THROUGH MOST IF NOT ALL OF
THE CWA AND THE PRECIPITATION WILL BE ENDING FROM WEST TO EAST
THROUGH THE EVENING HOURS. SINCE THE FRONT WILL BE NEARLY THROUGH
THE REGION BY NOON TOMORROW...THE THREAT FOR SEVERE WEATHER WILL
SHIFT EAST AND SOUTHEAST OF THE REGION...BUT A FEW ELEVATED
STORMS PRODUCING HAIL WILL STILL BE POSSIBLE BEHIND THE FRONT
DURING THE DAY TOMORROW.
TEMPERATURES BEHIND THE COLD FRONT ARE QUICKLY FALLING INTO THE
50S WITH TEMPERATURES IN THE 30S IN THE TEXAS PANHANDLE. EXPECT
TEMPERATURES TO FALL TONIGHT AS THE FRONT PASSES WITH OVERNIGHT
LOWS IN THE 30S ACROSS MOST AREAS WEST OF INTERSTATE 35/35W.
ONGOING RAIN AND CLOUD COVER TOMORROW WILL KEEP DAYTIME HIGHS IN
THE MID 40S TO MID 50S ACROSS MOST OF THE REGION. OVER THE EASTERN
COUNTIES...DAYTIME HIGHS WILL OCCUR EARLY IN THE MORNING WITH
FALLING TEMPERATURES FOR MUCH OF THE DAY. ON WEDNESDAY
NIGHT...AS THE WINDS DECREASE TO AROUND 5 MPH...TEMPERATURES WILL
FALL WITH OVERNIGHT LOWS IN THE 30S ACROSS MUCH OF THE REGION.
NEAR FREEZING TEMPERATURES ARE LIKELY WEST OF INTERSTATE 35 AND
NORTH OF INTERSTATE 20.
THE REMAINDER OF THE UPPER LEVEL TROUGH WILL PASS ACROSS THE
REGION ON THURSDAY AND BENIGN WEATHER IS EXPECTED THROUGH THE
REMAINDER OF THE FORECAST. ON FRIDAY...ANOTHER WEAK FRONT WILL
SLIDE ACROSS THE RED RIVER BUT IS NOT EXPECTED TO ADVANCE FARTHER
SOUTH THAN ABOUT INTERSTATE 20. TEMPERATURES BEHIND THIS FRONT
WILL NOT BE VERY COOL AND NOT MUCH TEMPERATURE CHANGE IS EXPECTED.
TEMPERATURES WILL CONTINUE TO WARM THROUGH THE WEEKEND WITH A
RETURN TO 80 DEGREE TEMPERATURES BY SUNDAY AND MONDAY. OUR NEXT
CHANCE FOR RAIN COULD BE BY THE MIDDLE OF NEXT WEEK WITH ANOTHER
COLD FRONT.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 37 63 43 70 49 / 10 0 0 5 5
WACO, TX 39 65 42 73 49 / 10 0 0 5 5
PARIS, TX 35 58 38 67 44 / 20 0 5 5 5
DENTON, TX 34 61 39 70 47 / 10 0 5 5 5
MCKINNEY, TX 34 61 38 69 46 / 10 0 5 5 5
DALLAS, TX 39 63 44 71 50 / 10 0 0 5 5
TERRELL, TX 35 62 41 70 47 / 10 0 0 5 5
CORSICANA, TX 38 63 43 72 49 / 10 0 0 5 5
TEMPLE, TX 40 67 42 74 49 / 10 0 0 5 5
MINERAL WELLS, TX 34 63 41 71 47 / 10 0 0 5 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
79/30
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1122 PM CDT TUE APR 9 2013
.UPDATE...
ONLY CHANGES MADE TO THE PREVIOUS FORECAST WERE TO ACCOUNT FOR
HOURLY TRENDS ASSOCIATED WITH THE CURRENT POSITION OF THE COLD
FRONT...AND TO SLOW DOWN THE TIMING OF THE ONSET OF SHOWERS AND
THUNDERSTORMS ACROSS NORTH AND CENTRAL TEXAS TONIGHT AND INTO
WEDNESDAY.
03Z WATER VAPOR IMAGERY INDICATED THAT THE UPPER LOW HAD NOT MOVED
MUCH THIS EVENING AND WAS ESSENTIALLY STATIONARY NEAR THE FOUR
CORNERS REGION. A SHORTWAVE TROUGH EMBEDDED IN THE FLOW AROUND THE
UPPER LOW WAS EVIDENT JUST SOUTHWEST OF EL PASO...MOVING
NORTHEAST. THE LARGE SCALE FORCING FOR ASCENT ASSOCIATED WITH THIS
TROUGH WAS SPREADING OVER WEST TX AND WAS WELL CORRELATED WITH THE
NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPING FROM CHILDRESS TO
SWEETWATER AT 04Z. THIS AREA OF SHOWERS AND STORMS ALSO APPEARS TO
BE WELL-CORRELATED WITH AN H850 FRONT THAT WAS LOCATED FROM
OKLAHOMA CITY TO SAN ANGELO ACCORDING TO REGIONAL VAD WIND
PROFILES. THE UPPER LEVEL FORCING FOR ASCENT AND THE H850 FRONT
WILL TRACK SOUTHEAST TONIGHT...AND SHOULD REMAIN ASSOCIATED WITH
NUMEROUS SHOWERS AND THUNDERSTORMS AS THESE FEATURES MOVE OVER
NORTH TX.
TRACKING THE H850 FRONT IN THE RAP AND NAM INDICATES THAT WE WILL
SEE WIDESPREAD RAIN SHOWERS AND THUNDERSTORMS WEST OF INTERSTATE
35 FROM MIDNIGHT THROUGH SUNRISE/12Z. WENT AHEAD AND PLACED 90
POPS FOR THESE AREAS AS A RESULT. THUNDERSTORMS WILL BE ELEVATED
WELL BEHIND THE SURFACE COLD FRONT LIMITING THE POTENTIAL FOR
DAMAGING WINDS AND ELIMINATING THE THREAT FOR TORNADOES
OVERNIGHT. HOWEVER THE FWD 00Z SOUNDING OBSERVED A LAYER OF STEEP
LAPSE RATES FROM 700 TO 300 MB INDICATING THAT THERE WILL CONTINUE
TO BE A THREAT FOR ELEVATED ORGANIZED CONVECTION CAPABLE OF
PRODUCING SEVERE HAIL TONIGHT THROUGH WEDNESDAY MORNING. UPSTREAM
CONVECTION HAS BEEN LARGELY MULTICELLULAR IN NATURE...HOWEVER RAP
FORECAST SOUNDINGS INDICATE OVER 1000 J/KG OF MUCAPE FOR AIR
PARCELS LIFTED IN THE H850 TO H750 LAYER. EFFECTIVE BULK SHEAR FOR
AIR LIFTED AT THIS LEVEL IS STILL FORECAST TO BE AROUND 50 KTS
WHICH IS SUPPORTIVE OF A SUPER CELLULAR STORM MODE...ALBEIT
ELEVATED SUPERCELLS.
AT ANY RATE...THINK THE THREAT FOR SEVERE HAIL WILL PERSIST
THROUGH THE OVERNIGHT HOURS INTO WEDNESDAY MORNING. HAIL UP TO
GOLFBALL SIZED CANNOT BE RULED OUT WITH ANY ELEVATED SUPERCELL.
THE EFFECTIVE LAYER HODOGRAPH /ESSENTIALLY THE 2.5 KM TO 6 KM
LAYER/ IS STRAIGHT LINE IN NATURE INDICATING A SHEAR PROFILE
WEAKLY VEERING WITH HEIGHT BUT DOMINATED BY SPEED SHEAR. IF
SUPERCELLS ARE REALIZED...THIS TYPE OF HODOGRAPH DOES SUPPORT
SPLITTING STORM STRUCTURES AND THE RIGHT OR LEFT MOVER COULD
REASONABLY EXIST FOR NEARLY THE SAME AMOUNT OF TIME. THIS DOESNT
CHANGE THE THREAT AT ALL AS BOTH STORMS WILL BE CAPABLE OF
PRODUCING MAINLY SEVERE HAIL...BUT IT IS SOMETHING WE WILL WATCH
FOR OVERNIGHT AS SPLITTING SUPERCELLS WILL EXHIBIT STORM MOTIONS
DEVIANT FROM THE MEAN UPPER FLOW. ANY TRAINING OF STORMS MAY LEAD
TO LOCALLY HEAVY RAINFALL AND FLOODING HOWEVER THIS IS NOT
EXPECTED TO BE A WIDESPREAD THREAT AT THIS TIME.
CONSIDERED ISSUING A WIND ADVISORY FOR THE STRONG UPSTREAM WINDS
BEHIND THE COLD FRONT...HOWEVER WILL HOLD OFF FOR NOW AS THE
STRONGEST WINDS APPEAR TO BE CONTAINED IN THE DEEPER COLD AIR MASS
LOCATED IN WESTERN OK AND THE TX PANHANDLE WHERE WINTRY WEATHER IS
ACCOMPANYING THE ONGOING THUNDERSTORM ACTIVITY. WE ARE NOT
ANTICIPATING ANY FREEZING TEMPERATURES ACROSS NORTH TX WHEN THE
WIDESPREAD RAIN SHOWERS AND STORMS BUILD IN...BUT WE WILL WATCH
TEMPERATURES CLOSELY THROUGHOUT THE OVERNIGHT HOURS...ESPECIALLY
NORTHWEST OF THE DFW METROPLEX.
CAVANAUGH
&&
.AVIATION...
/00Z TAFS/
THE STRONG COLD FRONT IS CURRENTLY LOCATED FROM NEAR MIDLAND TO
ABILENE TO WICHITA FALLS AND NORTHEAST FROM THERE AND WILL
CONTINUE TO MOVE SOUTH AND EAST THROUGH LATE TONIGHT. SCATTERED
SEVERE THUNDERSTORMS HAVE ATTEMPTED TO DEVELOP AND MAINTAIN
THEMSELVES OVER THE LAST FEW HOURS ACROSS NORTHWEST TEXAS BUT THE
COLD FRONT SEEMS TO BE UNDERCUTTING THESE STORMS CAUSING THEM TO
WEAKEN WITH TIME. NEW DEVELOPMENT CONTINUES ON THE SOUTHERN END OF
THE BROKEN LINE. IN THE NEAR TERM...VFR CONDITIONS SHOULD PREVAIL
WITH SOUTHERLY WINDS AROUND 20KTS AT THE MAJOR AIRPORTS. LATER
TONIGHT AS THE FRONT CONTINUES SOUTHEAST...WE SHOULD SEE A GENERAL
INCREASE IN THE COVERAGE OF SCATTERED SHOWERS AND THUNDERSTORMS.
THE FRONT SHOULD BE MOVING THROUGH THE METROPLEX AIRPORTS AROUND
MIDNIGHT TONIGHT WITH SCATTERED THUNDERSTORMS ALONG IT. COVERAGE
OF SHOWERS AND THUNDERSTORMS IS ACTUALLY EXPECTED TO INCREASE
AFTER THE FRONT PASSES THROUGH. STRONG FORCING FROM THE UPPER
LEVEL TROUGH WILL PERSIST THROUGH MUCH OF WEDNESDAY SO HAVE
EXTENDED THE PREVAILING PRECIPITATION THROUGH MIDDAY. INSTABILITY
ABOVE THE SHALLOW COLDER AIR WILL BE SUFFICIENT FOR ISOLATED
THUNDERSTORMS SO WILL ALSO LEAVE VCTS IN THROUGH MIDDAY. ON AND
OFF THUNDERSTORMS CAN BE EXPECTED WITH CIGS LOWERING TO IFR BY
MORNING. PRECIP WILL END FROM WEST TO EAST DURING THE DAY
WEDNESDAY WITH CIGS GRADUALLY IMPROVING.
DUNN
&&
.PREV UPDATE...
.UPDATE...
WE DID SEND UP A 20Z SOUNDING AND THE DATA WITH THIS RADIOSONDE
LOOKS MUCH MORE REPRESENTATIVE THAN THE PREVIOUS 18Z SOUNDING. WE
BELIEVE THE RADIOSONDE USED IN THE 18Z SOUNDING WAS BAD OR
DAMAGED. THE 20Z SOUNDING SHOWS A STOUT CAP STILL IN PLACE...BUT
WE KNOW THE CAP IS WEAKENING ALONG THE DRYLINE OVER OUR WESTERN
COUNTIES. HOWEVER...WE STILL THINK STORMS WILL NOT DEVELOP IN OUR
WEST AND NORTHWESTERN COUNTIES UNTIL THE FRONT ARRIVES IN A FEW
HOURS.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 324 PM CDT TUE APR 9 2013/
OVERALL THINKING REGARDING THE SEVERE WEATHER POTENTIAL FOR THE
NEXT 24 HOURS HAS NOT CHANGED. THE BIGGEST CHANGE IS THAT THE COLD
FRONT IS RAPIDLY MOVING THROUGH NORTHWEST TEXAS AND SOUTHWEST
OKLAHOMA AT THIS TIME AND IS STARTING TO OVERTAKE THE DRYLINE JUST
WEST OF VERNON. THE FRONT WILL CONTINUE RACING SOUTHEAST THIS
EVENING AND THE CHANCE FOR SEVERE STORMS DEVELOPING ALONG THE
DRYLINE IS QUICKLY DIMINISHING. HOWEVER...THE CAP HAS WEAKENED
NEAR AND IMMEDIATELY AHEAD OF THE FRONT. LOCAL SEVERE WEATHER
PARAMETERS ALSO INDICATE THE CAP HAS SUFFICIENTLY WEAKENED ALONG
THE DRYLINE OVER OUR WESTERN COUNTIES AND SOME SEVERE STORMS WILL
BE POSSIBLE ALONG THE COLD FRONT AS IT MOVES INTO OUR AREA THIS
EVENING. MOST OF THE STORMS THAT DEVELOP ALONG THE FRONT WILL BE
QUICKLY UNDERCUT BY THE COLD ARCTIC AIR BEHIND THE FRONT AND
BECOME ELEVATED. THUS...THE MAIN THREAT WITH THESE STORMS WILL BE
HAIL. THE THREAT FOR SEVERE STORMS WILL CONTINUE ALONG THE FRONT
OVERNIGHT AND WE WILL LIKELY SEE AN INCREASE IN STORM COVERAGE
ALONG AND BEHIND THE FRONT AS THE LOW LEVEL JET INCREASES AND
UPPER LEVEL LIFT INCREASES OVER THE REGION. HAIL WILL CONTINUE TO
BE THE MAIN THREAT OVERNIGHT.
LATEST TRACKING OF THE FRONT HAS IT REACHING OUR NORTHWEST
COUNTIES BETWEEN 00-01Z/7-8 PM CDT. HAVE ADJUSTED THE WINDS AND
POPS IN THE NEAR-TERM TO REFLECT THIS FASTER TIMING. DESPITE
HIGH POPS ACROSS THE REGION OVERNIGHT...COVERAGE MAY LIKELY BE
SPARSE AT FIRST BUT THEN INCREASE AS THE NIGHT PROGRESSES. BY
MIDDAY WEDNESDAY...THE FRONT WILL BE THROUGH MOST IF NOT ALL OF
THE CWA AND THE PRECIPITATION WILL BE ENDING FROM WEST TO EAST
THROUGH THE EVENING HOURS. SINCE THE FRONT WILL BE NEARLY THROUGH
THE REGION BY NOON TOMORROW...THE THREAT FOR SEVERE WEATHER WILL
SHIFT EAST AND SOUTHEAST OF THE REGION...BUT A FEW ELEVATED
STORMS PRODUCING HAIL WILL STILL BE POSSIBLE BEHIND THE FRONT
DURING THE DAY TOMORROW.
TEMPERATURES BEHIND THE COLD FRONT ARE QUICKLY FALLING INTO THE
50S WITH TEMPERATURES IN THE 30S IN THE TEXAS PANHANDLE. EXPECT
TEMPERATURES TO FALL TONIGHT AS THE FRONT PASSES WITH OVERNIGHT
LOWS IN THE 30S ACROSS MOST AREAS WEST OF INTERSTATE 35/35W.
ONGOING RAIN AND CLOUD COVER TOMORROW WILL KEEP DAYTIME HIGHS IN
THE MID 40S TO MID 50S ACROSS MOST OF THE REGION. OVER THE EASTERN
COUNTIES...DAYTIME HIGHS WILL OCCUR EARLY IN THE MORNING WITH
FALLING TEMPERATURES FOR MUCH OF THE DAY. ON WEDNESDAY
NIGHT...AS THE WINDS DECREASE TO AROUND 5 MPH...TEMPERATURES WILL
FALL WITH OVERNIGHT LOWS IN THE 30S ACROSS MUCH OF THE REGION.
NEAR FREEZING TEMPERATURES ARE LIKELY WEST OF INTERSTATE 35 AND
NORTH OF INTERSTATE 20.
THE REMAINDER OF THE UPPER LEVEL TROUGH WILL PASS ACROSS THE
REGION ON THURSDAY AND BENIGN WEATHER IS EXPECTED THROUGH THE
REMAINDER OF THE FORECAST. ON FRIDAY...ANOTHER WEAK FRONT WILL
SLIDE ACROSS THE RED RIVER BUT IS NOT EXPECTED TO ADVANCE FARTHER
SOUTH THAN ABOUT INTERSTATE 20. TEMPERATURES BEHIND THIS FRONT
WILL NOT BE VERY COOL AND NOT MUCH TEMPERATURE CHANGE IS EXPECTED.
TEMPERATURES WILL CONTINUE TO WARM THROUGH THE WEEKEND WITH A
RETURN TO 80 DEGREE TEMPERATURES BY SUNDAY AND MONDAY. OUR NEXT
CHANCE FOR RAIN COULD BE BY THE MIDDLE OF NEXT WEEK WITH ANOTHER
COLD FRONT.
82/JLD
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 43 50 37 63 43 / 60 70 10 0 0
WACO, TX 45 54 39 65 42 / 50 80 10 0 0
PARIS, TX 51 55 35 58 38 / 40 80 20 0 5
DENTON, TX 39 50 34 61 39 / 90 50 10 0 5
MCKINNEY, TX 42 47 34 61 38 / 50 90 10 0 5
DALLAS, TX 45 51 39 63 44 / 60 80 10 0 0
TERRELL, TX 48 52 35 62 41 / 30 90 10 0 0
CORSICANA, TX 53 57 38 63 43 / 30 90 10 0 0
TEMPLE, TX 47 56 40 67 42 / 50 90 10 0 0
MINERAL WELLS, TX 36 50 34 63 41 / 90 20 10 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
621 PM CDT THU APR 11 2013
.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 255 PM CDT THU APR 11 2013
MAIN FORECAST CONCERNS THIS CYCLE...PRECIPITATION TYPES YET THIS
EVENING... SNOW CHANCES/AMOUNTS LATER TONIGHT INTO FRI
NIGHT...TEMPERATURES.
DATA ANALYSIS AT 18Z HAD AN ELONGATED AREA OF LOW PRESSURE OVER
IA TO INDIANA WITH A BROAD AREA OF HIGH PRESSURE OVER HUDSONS
BAY. EAST AND NORTHEAST GRADIENTS WINDS BETWEEN THE TWO CONTINUED
TO BRING VERY COOL AIR INTO WI/MN/NORTHERN IA...WITH MID-DAY
TEMPS SOME 20 DEGREES BELOW THE MID APRIL NORMALS. WV IMAGERY
SHOWED THE BROAD MID LEVEL CIRCULATION SPINNING OVER THE CENTRAL
CONUS...WITH THE DRIER MID LEVEL AIR PUSHED NORTH OVER MUCH OF
IA/WESTERN WI AND SOUTH HALF OF MN. AREA RADARS/SURFACE OBS
SHOWED -RA/-DZ OVER MUCH OF IA/WI/SOUTHERN MN WITH SNOW CONFINED
TO NORTHERN MN/FAR NORTHERN WI WERE THE DEEPER MOISTURE REMAINED.
11.12Z MODELS LOOK TO HAVE SOLID INITIALIZATIONS. SOLUTIONS VERY
SIMILAR FOR TONIGHT AND FRIDAY. SOME DIFFERENCES BY FRI NIGHT
WITH HOW MUCH MID LEVEL TROUGHING REMAINS OVER THE REGION.
DPROG/DT OF 500MB HGTS AT 11.12Z SHOWED THE MODEL RUNS OF 09.12Z
AND 10.12Z VERIFIED QUITE WELL ACROSS NOAM/EASTERN PAC. HOWEVER
MOST EARLIER RUNS WERE A BIT TOO FAR EAST WITH THE MID LEVEL LOW
OVER IA/NEB. SOLUTIONS CONVERGING ON A TIGHTER/SLOWER CONSENSUS
AS THE MID LEVEL LOW LIFTS NORTHEAST ACROSS IA/WI TONIGHT/FRI.
MANY OF THE EARLIER RUNS TOO FAST PROGRESSING THIS SYSTEM OUT OF
THE REGION. SOME MODELS REMAIN VERY SLOW MOVING THIS SYSTEM EAST
OF THE REGION FRI NIGHT... DUE TO DIFFERENCES IN THE STRENGTH OF
A SHORTWAVE DROPPING DOWN THE MO RIVER VALLEY. UKMET/GEM STRONGER
THAN THE OTHERS WITH THIS WAVE AND HOLDING THE MID LEVEL LOW
FURTHER WEST THRU 12Z SAT. CHECK OF OBS VS. MODEL DATA AT 18Z
SHOWED ALL TO BE GOOD WITH THE IA TO IN SURFACE LOW. PER WV
IMAGERY ALL LOOKED REASONABLE WITH THE SHORTWAVE DETAILS OVER
NOAM/EASTERN PAC. A BLEND OF THE MODELS LOOKED BEST WITH THE 12Z-
18Z PRECIPITATION ACROSS THE UPPER MIDWEST. GIVEN THAT AND NO
CLEAR MODEL FAVORITE...AGAIN FAVORED A MODEL/ENSEMBLE CONSENSUS
THIS CYCLE. SHORT-TERM FCST CONFIDENCE REMAINS GOOD.
ALL MODELS DRIFT THE MID LEVEL LOW NORTHEAST TONIGHT AND NEAR
KLSE BY 12Z FRI...THEN MOVE IT TO NORTH OF KGRB BY 00Z SAT.
COLUMN CONTINUES TO COOL TONIGHT WITH MAX TEMP ALOFT VALUES
DROPPING BELOW ZERO AFTER MIDNIGHT ACROSS THE ENTIRE FCST AREA.
PROBLEM REMAINS DEPTH OF MOISTURE AND CLOUD TOPS BEING COOL
ENOUGH TO CONTAIN ICE... ESPECIALLY DURING THE EVENING. THE DEEP
COLD- CORE CIRCULATION CONTINUES TO PROVIDE CONVERGENCE/LIFT FOR
PRECIPITATION TONIGHT/FRI...AND CONTINUED 70-90 PERCENT
PRECIPITATION CHANCES OVER MUCH OF THE AREA TONIGHT AND 50-80
PERCENT OVER MAINLY THE NORTHEAST 2/3 OF THE FCST AREA FRI
MORNING...LOWERING FRI AFTERNOON AS THE MID LEVEL LOW MOVES
NORTHEAST OF THE FCST AREA. GIVEN THE STRONG SIGNAL FOR
PRECIPITATION TONIGHT AND COOLING COLUMN/BOUNDARY
LAYER...PRECIPITATION TYPE LOOKS TO BE -DZ/-RA BECOMING
-FZDZ/-FZRA THRU THE EVENING THEN MIXING WITH/CHANGING TO SNOW AS
DEEPER MOISTURE RETURNS AND CLOUDS WITH TOPS COLDER THAN -10C
MOVE IN AROUND/AFTER MIDNIGHT. SNOW AMOUNTS OF 1 TO 2 INCHES...
UP TO 3 INCHES IN TAYLOR CO...LATER TONIGHT/FRI MORNING COMBINED
WITH THE -FZDZ/-FZRA THIS EVENING...WILL ISSUE A WINTER WEATHER
ADVISORY FOR TONIGHT THRU NOON FRI FOR MOWER TO VERNON AND ADAMS
COUNTIES NORTHWARD. WITH LESS OF A -FZDZ THREAT THIS EVENING AND
AN INCH OR LESS OF SNOW LATER TONIGHT/FRI MORNING...LEFT
NORTHEAST IA/FAR SOUTHWEST WI OUT OF ANY ADVISORY FOR NOW.
BOUNDARY LAYER TEMPS LOOK TO COOL ENOUGH LATER TONIGHT THAT ANY
SNOW MAY MELT ON THE ROADS THEN REFREEZE...ESPECIALLY ON BRIDGE
DECKS/OVERPASSES...MAKING FOR SOME SLIPPERY/ICY TRAVEL CONDITIONS
YET TONIGHT/FRI MORNING.
QUIETER WEATHER FRI NIGHT...BUT STILL NOT VERY SPRING-LIKE. WITH
THE SURFACE-MID LEVEL LOW REMAINING NEARBY...THE SECONDARY
SHORTWAVE DROPPING IN AND A SURFACE-500MB TROUGH REMAINING OVER
THE AREA... CONTINUED A 20-40 PERCENT CHANCE OF -SN ACROSS THE
FCST AREA. ANY SNOW AMOUNTS FRI NIGHT WOULD BE MINIMAL...BUT
SNOWFLAKES IN THE AIR AND TEMPS IN THE MID/UPPER 20S WILL NOT
SEEM LIKE MID APRIL.
FAVORING THE MODEL/ENSEMBLE CONSENSUS...USED A BLEND OF THE
NUMERICAL GUIDANCE LOWS/HIGHS FOR TONIGHT/FRI/FRI NIGHT...WHICH
REMAIN SOME 10-20 DEGREES BELOW THE NORMALS.
.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 255 PM CDT THU APR 11 2013
11.00Z/11.12Z MODELS IN GOOD AGREEMENT FOR SOME TROUGHING TO
LINGER OVER MN/IA/WI INTO SAT MORNING...DUE IN PART TO THE
SECONDARY SHORTWAVE DROPPING SOUTHEAST ACROSS IOWA. CONSISTENCY
REMAINS GOOD FOR A TRANSIENT SHORTWAVE RIDGE TO MOVE ACROSS THE
UPPER MIDWEST LATE SAT/SAT NIGHT...WITH THE NEXT SHORTWAVE TROUGH
RAPIDLY MOVING INTO THE NORTHERN PLAINS SUNDAY. TREND BY SUNDAY
FAVORS STRONGER OF THE EARLIER MODELS WITH THE NORTHERN PLAINS
TROUGH.
GIVEN THE PASSING SHORTWAVE...SOME WEAK LOWER LEVEL
CONVERGENCE/LIFT WITH A WEAK SURFACE-850MB TROUGH AND SOME DEEPER
MOISTURE...ADDED FLURRY/SMALL -SN MENTION TO SAT MORNING GRIDS.
SURFACE-850MB RIDGE AXIS PUSHES QUICKLY EAST INTO/ACROSS THE AREA
SAT AFTERNOON/EVENING. WILL LEAVE THESE PERIODS DRY WITH A
DECREASE OF CLOUDS.
WITH THE STRONGER TROUGH INTO THE NORTHERN PLAINS BY
SUNDAY...LOWER LEVEL WARM ADVECTION/ISENTROPIC LIFT AND MOISTURE
INCREASE AHEAD OF IT SPREADS QUICKLY INTO THE AREA LATER SAT
NIGHT. BIGGEST QUESTION LATE SAT NIGHT/SUN MORNING...WILL
PRECIPITATION OCCUR ON/AHEAD OF THE LEADING EDGE OF THE 925-850MB
LAYER WARMING ABOVE 0C. MODEL X- SECTIONS INDICATING SOME OF THE
SATURATION/LIFT/PRECIPITATION WILL OCCUR AHEAD OF OR ON THE EDGE
OF THE WARMING ALOFT. THIS AROUND 12Z SUN WHEN BOUNDARY LAYER
TEMPS WILL BE COOLEST AS WELL. APPEARS AS PRECIPITATION SPREADS
NORTHEAST ACROSS THE AREA LATE SAT NIGHT/SUN MORNING IT WOULD
START AS BRIEF PERIOD OF -SN THEN MIX WITH/CHANGE TO PL/-FZRA
BEFORE BOUNDARY LAYER TEMPS WARM ABOVE FREEZING AND 925-850MB
TEMPS WARM WELL ABOVE 0C. RAISED PRECIPITATION CHANCES ON SUNDAY
TO AROUND 80 PERCENT...TAPERING THEM OFF/LOWERING THEM SUN NIGHT
AS THE COLD FRONT/LOW LEVEL TROUGH PASS. SMALL TSRA CHANCE ACROSS
THE SOUTHEAST END OF THE FCST AREA SUN AFTERNOON/EVENING...WHEN
SOME WEAK CAPE IN THE 850-700MB LAYER MAY MOVE IN AHEAD OF THE
SURFACE-700MB COLD FRONT/ TROUGH...LOOKS GOOD.
FOR MON-THU...CONSENSUS OF 11.00Z/11.12Z MEDIUM RANGE MODEL RUNS
LEAVES A BIT TO BE DESIRED ALREADY ON MON...AS THE SUN/SUN NIGHT
TROUGH LIFTS NORTHEAST OF THE REGION. MODEST AGREEMENT WITH THEIR
RUNS OF 10.00Z WITH A TREND TO FAVOR STRONGER OF THE EARLIER RUNS
AND A COMPROMISE ON TIMING. IMPROVING CONSENSUS TUE AS THE NEXT
STRONG TROUGHING DIGS INTO THE SOUTHERN ROCKIES AND RISING HGTS/
RIDGING OVER THE CENTRAL CONUS AHEAD OF IT. TREND HERE ALSO
FAVORS SLOWER/STRONGER OF EARLIER RUNS WITH BETTER RUN-TO-RUN
CONSISTENCY BY ECMWF. BY WED/THU DIFFERENCES BETWEEN ECMWF/GFS
BEGIN TO INCREASE WITH THE EVOLUTION OF THE TROUGH/ENERGY AS IT
EJECTS INTO THE CENTRAL CONUS WED...LIFTING INTO THE MID/UPPER MS
VALLEY THU. THIS RESULTS IN PLENTY OF DETAIL DIFFERENCES BY DAYS
6/7...BUT MAIN SIGNAL IS A STRONG PIECE OF TROUGHING/ENERGY LOOKS
TO IMPACT THE UPPER MIDWEST THE MIDDLE OF NEXT WEEK WITH THE
THREAT OF MORE HEAVY PRECIPITATION. WITH NO CLEAR MODEL FAVORITE
AND TREND TOWARD A COMMON CONSENSUS MON/TUE...SIDED WITH THE
MODEL/ENSEMBLE CONSENSUS FOR MON-THU.
HGTS ALOFT OVER THE UPPER MIDWEST RISE MON/TUE AS ONE TROUGH
EXITS AND SIGNIFICANT TROUGHING DIGS INTO THE CENTRAL/SOUTHERN
ROCKIES. THIS AS CAN HIGH PRESSURE NOSES INTO THE NORTHERN
PLAINS/UPPER MS VALLEY. HOWEVER...WITH SOME LINGERING LOWER LEVEL
MOISTURE OVER THE AREA...SOUTHWEST FLOW ALOFT AND A STRONG
FRONTAL BOUNDARY ACROSS THE MID MS VALLEY...SOME SMALL MAINLY
RAIN CHANCES ACROSS MAINLY THE SOUTH HALF OF THE FCST AREA
MON/TUE REASONABLE. PRECIPITATION CHANCES INCREASE AGAIN FOR TUE
NIGHT INTO THU AS ALL OR A MAJOR PORTION OF THE WESTERN CONUS
TROUGH EJECTS NORTHEAST INTO THE MID/UPPER MS VALLEY.
AGAIN...DETAILS SKETCHY BY WED/THU WITH THE THE MODEL DIFFERENCES
BUT MODEL CONSENSUS PAINTS ANOTHER SIGNIFICANT PRECIPITATION EVENT
FOR THE AREA. GFS WOULD GIVE MUCH OF THE AREA 12+ INCHES OF SNOW
WHILE ECMWF PRODUCES ANOTHER 0.5 TO 1.5 INCHES OF RAIN. FOR NOW
MODEL/ENSEMBLE CONSENSUS FOR HIGHS/LOWS/PRECIPITATION CHANCES IN
THE DAY 4-7 PERIOD REASONABLE UNTIL DETAILS SORT THEMSELVES OUT
AND CLEARER SIGNALS SEEN.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 621 PM CDT THU APR 11 2013
SURFACE TROUGH OF LOW PRESSURE IS STILL SOUTH OF THE AREA ACROSS
NORTHERN IOWA. ISENTROPIC UP GLIDE OF 2 TO 4 UBAR/S ON THE 295K
SURFACE CONTINUES OVER THE REGION NORTH OF THIS SURFACE TROUGH.
THIS IS HELPING TO MAINTAIN THE LIGHT DRIZZLE WHERE THERE IS A
LACK OF ICE IN THE CLOUDS AND LIGHT SNOW ELSEWHERE. KRST RECENTLY
SWITCHED OVER TO LIGHT SNOW AND KARX RADAR SHOWS AN EXPANDING AREA
OF HIGH CC/S IN THAT AREA SUGGESTING THE PRECIPITATION TYPE IS
BECOMING MORE UNIFORM. STILL MAY SEE SOME DRIZZLE OR FREEZING
DRIZZLE THERE AT TIMES THIS EVENING AS FORECAST SOUNDINGS FROM THE
11.18Z NAM AND 11.20Z RAP DO NOT SUGGEST ICE WILL CONSISTENTLY BE
IN THE CLOUDS UNTIL LATER THIS EVENING. FOR KLSE...WILL KEEP
PREVIOUS FORECAST TRENDS OF DRIZZLE BECOMING LIGHT FREEZING
DRIZZLE FOR A SHORT PERIOD BEFORE GOING OVER TO LIGHT SNOW.
EXPECTING THE LIGHT SNOW TO CONTINUE THROUGH THE NIGHT WITH MVFR
VISIBILITIES AND IFR CEILINGS. THE SURFACE TROUGH SHOULD LIFT
THROUGH EARLY FRIDAY MORNING ALLOWING THE WINDS TO COME AROUND TO
THE NORTHWEST WITH THE LIGHT SNOW ENDING. HOWEVER...LOW LEVEL
INSTABILITY LOOKS LIKE IT WILL QUICKLY DEVELOP SETTING UP THE
POSSIBILITY OF SNOW SHOWERS FOR THE LATE MORNING AND AFTERNOON.
CONFIDENCE ON WHEN OR IF THESE WOULD HIT EITHER TAF SITE IS TOO
LOW TO INCLUDE ANYTHING MORE THAN VCSH AT THIS TIME. WITH THE
SWITCH TO NORTHWEST WINDS...EXPECT THE VISIBILITY WILL BECOME VFR
WITH CEILINGS GOING UP TO MVFR.
&&
.HYDROLOGY...TONIGHT INTO SUNDAY NIGHT
ISSUED AT 255 PM CDT THU APR 11 2013
WITH A BREAK FROM THE WIDESPREAD MDT/HEAVY RAINS AND COLDER TEMPS
TONIGHT THRU SAT NIGHT...RUNOFF AND ANY REMAINING SNOW MELT WILL
SUBSIDE. MOST RIVERS AND STREAMS NEAR OR ABOVE FLOOD STAGE WILL
RECEDE OR BEGIN TO RECEDE. THE EXCEPTIONS WILL BE THE LOWER PORTIONS
OF THE KICKAPOO RIVER WERE LEVELS WILL CONTINUE TO RISE...AND ALONG
THE MS RIVER...WITH THE INFLOW OF THE TRIBUTARY RIVERS REACHING THE
MAIN CHANNEL DURING THE NEXT FEW DAYS.
OF CONCERN THOUGH IS THE NEXT SYSTEM TO IMPACT THE AREA WITH SOME
WIDESPREAD RAINS POSSIBLE SUNDAY/SUNDAY NIGHT. CURRENT MODEL
CONSENSUS WOULD SPREAD 1/2 TO 1 INCH OF PRECIPITATION ACROSS THE AREA THRU
THE SUN/SUN NIGHT PERIOD. DEPENDING ON POTENTIAL FOR CONVECTION AND
HIGHER RAINFALL RATES...THESE RAINS COULD CREATE ADDITIONAL RUNOFF
AND MORE FLOODING CONCERNS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...WINTER WEATHER ADVISORY UNTIL NOON CDT FRIDAY FOR WIZ017-029-
032>034-041>044-053.
MN...WINTER WEATHER ADVISORY UNTIL NOON CDT FRIDAY FOR MNZ079-086>088-
094>096.
IA...NONE.
&&
$$
SHORT TERM...RRS
LONG TERM....RRS
AVIATION...04
HYDROLOGY....RRS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
416 AM EDT FRI APR 12 2013
.SYNOPSIS...
ISSUED AT 350 AM EDT FRI APR 12 2013
SLOW MOVING...LOW PRESSURE IS LIFTING INTO THE UPPER GREAT LAKES
REGION AND WILL BRING A WINTRY MESS OF PRECIPITATION TYPES TO
NORTHERN MICHIGAN TODAY. THE FREEZING RAIN AND SLEET IS EXPECTED TO
TRANSITION OVER TO SNOW AND DRIZZLE THIS MORNING. THIS WILL CONTINUE
INTO THE EVENING BEFORE CHANGING TO ALL SNOW TONIGHT. HIGH PRESSURE
TRIES TO SNOW INTO THE REGION ON SATURDAY SO THAT WE WILL GET A
BREAK FOR THE WEEKEND.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 350 AM EDT FRI APR 12 2013
CURRENTLY...POTENT UPPER LEVEL CLOSED LOW IS DRIFTING ACROSS THE
FAR NRN MISSISSIPPI VALLEY...WITH OCCLUDED LOW PRESSURE FROM THE
APPALACHIANS...AND TROUGHING/TROWAL EXTENDING BACK INTO SRN
WISCONSIN. MAIN H8-H7 WARM ADVECTION EXTENDS ALONG H8 WIND SPEED
MAX WHICH IS NOW EXTENDING FROM THE EASTERN GREAT LAKES BACK AROUND
THROUGH EASTERN UPPER MICHIGAN. THIS IS WHERE ONE SWATH OF BETTER
PRECIPITATION...IN THE FORM OF SNOW AND SOME SLEET...IS CO-LOCATED
WITH STRONG POCKET OF UPPER DIVERGENCE IN RIGHT ENTRANCE REGION OF
QUEBEC 120+KT UPPER JET. ANOTHER JET STREAK WAS CROSSING THE OHIO
RIVER VALLEY...AND ANOTHER POCKET OF UPPER DIVERGENCE IN LEFT EXIT
REGION OF WAS DEVELOPING ACROSS THE EASTERN GREAT LAKES. DPVA
AROUND THE CLOSED LOW ALOFT...COMBINED WITH THESE FORCING
MECHANISMS...HAS RESULTED IN MODEST TO STRONG DEEP LAYER LIFT AND
WIDESPREAD PRECIPITATION ACROSS MAINLY NE LOWER AND BACK AROUND
THROUGH EASTERN UPPER.
NOW...THERMALLY SPEAKING...WE HAVE GONE THROUGH QUITE ALONG PERIOD
OF SLEET AND FREEZING RAIN IN NRN LOWER...AS 00Z APX SOUNDING TELLS
THE STORY. 800-700MB DEEP 2-3C WARM NOSE IS EVIDENT...WITH A
COUNTERING DEEP SFC-800MB COLD LAYER WITH A MAXIMUM -6C READING AT
900MB...COLD ENOUGH TO RE-FREEZE TOTALLY MELTED DROPS FROM THAT 2-3C
DEEP WARM NOSE. ONE OF THE BETTER SLEET SOUNDINGS THIS FORECASTER
HAS SEEN. AS THE ENTIRE SYSTEM HAS BEEN SLOW TO TRANSITION NORTH AND
EAST WITH TIME...QUITE A BIT OF SLEET HAS BEEN ABLE TO FALL AND
ACCUMULATE. ACROSS EASTERN UPPER...SOME SLEET MAY BE TRYING TO MIX
WITH WHAT SHOULD BE PRIMARILY SNOW...BASED ON LATEST DUAL POL RADAR
LOOPING. RUC FCST SOUNDINGS ALSO SUGGEST ALL SNOW IN EASTERN
UPPER...WITH THE ELEVATED WARM COOLING STARTING AS OF THIS WRITING.
LATEST OBS SUGGESTING THAT THIS MAY BE TAKING PLACE NOW WITH MORE
OBSERVATIONS ACROSS THE WEST NOW LOOKING MORE "SNOWY" RATHER THAN
"ICY". ALSO IN THE MIX...IS THE CURRENT EFFORT FOR DEEPER MOISTURE
TO STRIP OUT ALOFT FROM THE WEST...WHICH ALLOWS US TO EXPERIENCE YET
ANOTHER PRECIPITATION TYPE...DRIZZLE AND FREEZING DRIZZLE.
IT SHOULD BE WORTH NOTING THAT NOT ALL FOLKS HAVE EXPERIENCED THIS
PLETHORA OF NASTY WINTRY WEATHER. DOWNSLOPING REGIONS ACROSS NW
LOWER...MAINLY FRANKFORT AND MANISTEE AREAS...WERE ABOVE FREEZING
FOR MUCH OF THE NIGHT...SO NOT FREEZING RAIN THERE.
IN THE SPIRIT OF A FORMER NWS COLLEAGUE..."WELL...AT LEAST IT`S
WINDY". YEAH...EAST WINDS WERE GUSTING AS HIGH AS 35-40 MPH MUCH OF
THE NIGHT TOO.
NOW...THE FORECAST...POTENT UPPER LOW WILL LIFT INTO EASTERN LAKE
SUPERIOR TODAY AND TONIGHT...WITH THE SFC TROUGHING/TROWAL AND
AXIS OF DEEPER MOISTURE AND FORCING LIFTING NORTH AND EAST
THROUGH THE MORNING. COLDER AIR SEEPS IN...AND THE TRANSITION OVER
TO MAINLY LIGHT SNOW WILL BE JOINED BY DRIZZLE AND FREEZING
DRIZZLE DUE TO DRYING ALOFT. THE THERMAL PROFILES BECOME AN
INCREASINGLY LIGHT SNOW/DRIZZLE LOOK...AS MOISTURE WILL BE AT OR
BELOW 10C FOR MOST OF THE DAY AND EVEN INTO THE EVENING. THE BEST
MOISTURE/FORCING WILL BE ACROSS CHIPPEWA COUNTY FOR THE LONGEST
PERIOD OF TIME. HERE...ALTHOUGH TOTAL QPF/SNOWFALL WERE LOWERED
SLIGHTLY...WILL STILL SEE A GRAND TOTAL OF 4 TO 8 INCHES BY THE
END OF THE DAY. LESSER AMOUNTS HEADING SOUTH UNTIL JUST AN INCH
DOWN NEAR THE M-55 CORRIDOR. CURRENT WINTER STORM HEADLINES WILL
HOLD TRUE...ENDING FROM SOUTH TO NORTH THROUGH THE DAY. LIGHT
SNOWS AND DRIZZLE ARE LIKELY AT LEAST INTO THE EVENING DUE TO THE
LOW LEVEL CONVERGENCE ASSOCIATED WITH THE ACTUAL SFC TROUGHING.
EVENTUALLY BY LATER TONIGHT...THE LOW LEVEL TROUGHING
WEAKENS/DEPARTS...WITH THE ENTIRE ATMOSPHERIC COLUMN COLD ENOUGH
FOR JUST SNOW. CAN MAKE A REAL GOOD ARGUMENT FOR LIKELY SNOWS FOR
MOST EVERYONE AT SOME POINT DURING THE NIGHT. THIS DUE NOT ONLY TO
THE LINGERING TROUGHING AT THE SFC...BUT ALSO WITH MID LEVEL
TROUGHING WITH THE UPPER CIRCULATIONS...WHICH WILL BE ALIGNED
ACROSS EASTERN UPPER. THUS...WILL HAVE THE BETTER ACCUMULATIONS
AND CHANCES FOR SNOW THERE. MAYBE ANOTHER INCH ACROSS EASTERN
UPPER...WITH LESSER AMOUNTS HEADING FURTHER SOUTH.
CLOUDY THROUGH THE PERIOD WITH LITTLE DIURNAL SWINGS IN
TEMPERATURE. HIGHS IN THE 30S TODAY...WITH LOWS IN THE MIDDLE 20S
TO LOWER 30S.
&&
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM EDT FRI APR 12 2013
SATURDAY...AS THE 500 MB LOW DRIFTS EAST JUST NORTH OF THE FORECAST
AREA, THERE WILL BE ENOUGH FORCING TO CONTINUE THE SNOW SHOWERS.
HOWEVER, THE KICKER IS THAT THE 850 MB TEMPERATURES FALL TO AROUND
-10C AND WITH THE WATER TEMPERATURES SLIGHTLY WARMER AROUND +1 TO
+2C WE WILL PROBABLY GET SOME ENHANCEMENT ESPECIALLY NEARER THE SFC
AND 500 MB LOWS. SO WILL HAVE AN AREA OF LIKELY POPS IN E UPPER AND
ENHANCED CHANCE POPS IN NW LOWER. BY 00Z, THINGS BEGIN TO LOOK LIKE
LAKE EFFECT, HOWEVER, THE PROBLEM IS THAT THE 850 MB TEMPERATURES
BEGIN TO WARM BIT, AND WE LOSE THE ENHANCEMENT.
SATURDAY NIGHT...WE LOSE GOOD 850 MB AND SFC FLOW AS THE
TEMPERATURES RISE TO AROUND -8C. WILL ALLOW FOR SOME FLURRIES EARLY,
BUT ALL THINGS BEING EQUAL, THINK THAT THE WITH THE DRIER AIR MOVING
IN AS WELL, THAT THE SNOW WILL STOP SHORTLY HAVE 00Z.
SUNDAY...THE NEXT SYSTEM BEGINS TO LIFT NORTH INTO NORTHERN PLAINS.
THE GFS HAS IT A LITTLE MORE EAST IN MINNESOTA, WHILE THE 00Z ECMWF
HAS IT IN E NORTH DAKOTA. THE DIFFERENCE IS THAT THE GFS BRINGS
CHANCE POPS INTO NW LOWER SOONER. WITH THESE SYSTEMS BEING KIND OF
ALL OVER THE PLACE, IN THE RUN UP TO THEM, WILL HEDGE BETWEEN THE
TWO. SO CUT THE POPS BACK SO THAT NW LOWER HAVE SOME CHANCE POPS,
AND THE REST OF THE REGION IS RELATIVELY DRY. OVERNIGHT, THE WARM
FRONT IN EITHER CASE MAKES IT FAR ENOUGH NORTH RAIN TAKES OVER IN E
UPPER. THE FRONT STALLS THERE AS WELL SO THAT THE SFC LOW RIDES UP
INTO LAKE SUPERIOR ALONG IT. SO RAIN WILL BE EXPECTED IN E UPPER AND
WITH THE WARM SECTOR MOVING NORTH WILL HAVE LESS CHANCES TO THE
SOUTH.
EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, EXPECTING RAIN FROM THE
SYSTEM MOVING THROUGH DURING THE DAY. OVERNIGHT, WITH THE FRONT
THROUGH AND THE SFC LOW TO THE EAST, WILL EXPECT THAT E UPPER AND
PORTIONS OF N LOWER WILL CLEAR OUT AS HIGH PRESSURE BUILDS INTO THE
REGION. TUESDAY, THE FRONT HOLDS TO THE EAST WITH HIGH PRESSURE
NOSING INTO LOWER MICHIGAN. LOOKS LIKE SOME RAIN COULD HOLD ON WITH
WAVES RUNNING UP THE FRONT. SO WILL ALLOW FOR SOME RAIN IN NE
LOWER. WEDNESDAY, THE NEXT SYSTEM BEGINS TO PUSH OUT OF THE SOUTHERN
PLAINS AND BY THE TIME THAT IT GETS INTO THE MID-MISSISSIPPI VALLEY,
THE RAIN WILL SPREAD BACK NORTH THROUGH N LOWER AND IN E UPPER,
WHERE A MIX WILL BE EXPECTED. OF COURSE, THE WARM AIR WILL CONTINUE
NORTH CHANGING THE SNOW BACK TO RAIN OVERNIGHT. THURSDAY, THE MODELS
HAVE TWO DIFFERENT TRACKS. THE ECMWF STILL BRINGS THE SFC LOW OVER N
LOWER, WHICH WOULD BRING MORE RAIN TO THE REGION BEFORE CHANGING TO
SNOW THURSDAY NIGHT. THE GFS BRINGS THE SFC LOW UP THROUGH LAKE
ERIE. THIS WOULD BRING SNOW OR RAIN AND SNOW TO N LOWER AND E UPPER.
DECIDED TO PLAY AS RAIN THURSDAY, RAIN/SNOW THURSDAY NIGHT FOR NOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 132 AM EDT FRI APR 12 2013
ICY MIX OF PRECIP OVERNIGHT. MAINLY MVFR CONDITIONS (CIGS) FRIDAY.
COMPLEX AREA OF LOW PRESSURE ACROSS THE SOUTHERN GREAT LAKES...WILL
LIFT NORTH TO NORTHERN LAKE HURON BY THURSDAY EVENING. WINTRY PRECIP
CONTINUES AT MOST TAF SITES...WITH PLN SEEING MOSTLY -SN (IFR) AND
APN/TVC PL/FZRA/RA (MVFR TO IFR). MBL IS OUT OF THE WORST OF
IT...WITH ONLY RATHER LIGHT PRECIP EXPECTED. APN/TVC WILL TRANSITION
TO SN/DZ BEFORE ENDING FRIDAY. CIGS ARE MOSTLY MVFR...AND WILL
REMAIN SO...THOUGH WITH SOME VARIABILITY OVERNIGHT.
BLUSTERY EAST WINDS WILL BACK NE AND WEAKEN A BIT TONIGHT AND
ESPECIALLY FRIDAY. WINDS SHIFTING TO THE W/NW LATE FRIDAY.
&&
.MARINE...
ISSUED AT 350 AM EDT FRI APR 12 2013
GALE FORCE GUSTS ARE IN FULL EFFECT ACROSS MOST OF THE SURROUNDING
NEARSHORE WATERS OF LAKES HURON AND MICHIGAN...NORTH OF GRAND
TRAVERSE LIGHT AND STURGEON POINT LIGHT. NORTH OF THERE...SOLID
ADVISORY LEVEL GUSTS WERE ONGOING...WHILE SOUTH OF THE
GALES...WINDS WERE DROPPING OFF RATHER QUICKLY WITH A LOOSE
GRADIENT ALONG LOW PRESSURE LIFTING NORTHWARD. THIS LIGHTER
GRADIENT WILL GRADUALLY OVERTAKE ALL OF THE NEARSHORE WATERS
THROUGH THE DAY...WITH GALES GRADUALLY STEPPING DOWN INTO
ADVISORY...THEN SUB ADVISORY LEVELS. THE LOW PRESSURE LIFTS EAST
TONIGHT...WITH COLD ADVECTION AND WESTERLY WINDS DEVELOPING...BUT
EXPECTATIONS ARE FOR WINDS TO BE BELOW ADVISORY LEVELS THROUGH
EARLY SUNDAY. THE NEXT LOW PRESSURE SYSTEM IS SET FOR LATER SUNDAY
AND INTO MONDAY. ADDITIONAL HEADLINES MAY BE REQUIRED.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 9 AM EDT THIS MORNING FOR MIZ020-
025>036-041-042.
WINTER STORM WARNING UNTIL NOON EDT TODAY FOR MIZ016>019-021>024.
WINTER STORM WARNING UNTIL 7 PM EDT THIS EVENING FOR MIZ008-015.
LH...GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LHZ345>349.
LM...GALE WARNING UNTIL 8 AM EDT THIS MORNING FOR LMZ341-342.
LS...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR LSZ321-322.
&&
$$
SYNOPSIS...JL
SHORT TERM...SD
LONG TERM...JL
AVIATION...JZ
MARINE...SD
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1255 AM EDT FRI APR 12 2013
.AVIATION...
//DISCUSSION...
IFR CEILINGS AND RAIN SHOWERS WILL PERSIST OVERNIGHT...AS LOW
PRESSURE TRACKS INTO THE EASTERN GREAT LAKES. A WIND SHIFT TO THE
SOUTHWEST AND MID LEVEL DRY SLOT ARRIVING WILL ALLOW RAIN TO
TAPER OFF BETWEEN 10-12Z. PLENTY OF LOW LEVEL MOISTURE HOWEVER
SHOULD ASSURE MVFR CEILINGS TODAY INTO TONIGHT...WITH A LOW CHANCE
OF RAIN SHOWERS THIS AFTERNOON. THERE WILL THEN BE A LOW CHANCE OF
RAIN AND OR SNOW SHOWERS TONIGHT...BUT CONVERGE UNCERTAINTY DOES
NOT WARRANT INCLUSION IN TAFS.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE ON CEILING BELOW 5000 FT THROUGH THE TAF PERIOD.
&&
.PREV DISCUSSION...ISSUED 927 PM EDT THU APR 11 2013
UPDATE...
WITNESSING A BIFURCATION OR SPLITTING OF THE MAIN PRECIPITATION
SWATH (ALABAMA TO MICHIGAN) INTO TWO BRANCHES. THIS IS OCCURRING AT
THE FAR NORTHERN END/OVER MICHIGAN DUE TO DIFFLUENCE OF SYSTEM
RELATIVE FLOW IN THE 500-300 MB LAYER. THE ANTICYCLONIC BRANCH
(EAST..RIGHT) IS HARBORING THE PRECIPITATION NOW PUSHING INTO AREAS
SOUTH OF DETROIT. EXPECT THIS TO CONTINUE TO LIFT
NORTHWARD...WHILE TRENDING EAST OR BRUSHING THE CWA THROUGH THE
EVENING. EARLIER MODELS WERE SUGGESTING THIS WOULD ROCKET
THROUGH...ENDING BY 5Z TONIGHT HOWEVER...11.23Z RUC IS MORE
REPRESENTATIVE WITH THE CURRENT PRECIP SHIELD AND HAS END TIMING BY
7Z. IT IS THIS ANTICYCLONIC BRANCH THAT PERTAINS TO THE WARM THETA
E SURGE THAT WILL OCCUR OVER THE EASTERN HALF OF THE CWA. EXPECT A
STRAIGHT RAIN WITH TEMPERATURES THAT WILL EVEN RISE A COUPLE OF
DEGREES MOVING FORWARD. GIVEN THE RUC DEPICTION EXPECTING THIS WAA
TO LIFT NORTHWARD THROUGH THE THUMB...LARGELY HOLDING OFF ANY
PRECIPITATION TYPE CONCERNS.
THE PRECIPITATION DEVELOPING (AN HOUR OR TWO EARLIER THAN EXPECTED)
OVER WESTERN LOWER MICHIGAN IS ASSOCIATED WITH THE CYCLONIC BRANCH
(WEST...LEFT). THIS PRECIPITATION IS EXPECTED TO FILL IN AND SLOW
DOWN DURING THE DURATION OF THE EVENING WHILE LIFTING NORTHWARD
AND TRYING TO ALIGN WEST NORTHWEST TO EAST SOUTHEAST. THE CURRENT
TRAJECTORY OF THE PRECIPITATION IS DEVELOPING AS EXPECTED...TRACKING
TOWARDS THE SAGINAW VALLEY. EARLIER...MADE SOME PHONE CALLS AFTER
READING THE REPORT OF FREEZING RAIN FROM A NEIGHBORING OFFICE.
THERE WERE MULTIPLE REPORTS OF CARS SLIDING OFF ROADWAYS AND SLICK
TRAVEL CONDITIONS IN MIDLAND COUNTY. SUSPECT MUCH OF THIS GLAZING
OCCUR ED WITH THE HEAVIER PRECIPITATION RATES/EVAPORATIVE COOLING
POTENTIAL OF THE CONVECTIVE SHOWERS THAT LIFTED THROUGH THE
COUNTY BETWEEN 21-23Z. MOVING FORWARD...CYCLONIC BRANCH TRANSPORT
SHOULD LIFT INTO BAY AND MIDLAND COUNTIES BRINGING CONTINUED
CHANCES FOR LIGHT TO MODERATE PRECIPITATION THIS EVENING. A ZONAL
+90 KNOT JET OVER OKLAHOMA IS CURRENTLY DIGGING THROUGH THE BASE
OF THE TROUGH. THIS ACTION SHOULD CAUSE THE CLOSED LOW TO ROTATE
WHILE LOFTING THE POTENTIAL VORTICITY ANOMALY INTO WISCONSIN. IN
RESPONSE TO THE LOW CREEPING CLOSER...EXPECT TROWAL DYNAMICS TO
INCREASE ACROSS THE NORTHERN CWA BY 3Z PERSISTING THROUGH 9Z.
AS NOTED EARLIER...THE BULK OF WARM AIR ADVECTION WILL OCCUR OVER
THE EASTERN CWA...SO PRECIPITATION TYPE CONCERNS WILL CONTINUE.
850MB THERMAL PROGS SHOW ENOUGH WARM AIR WITHIN THE BOLSTERING TROWAL
TO SUPPORT A PREDOMINATE LIQUID TYPE. GIVEN THE CONCERNS THE
DECISION WAS MADE TO ISSUE A WINTER WEATHER ADVISORY FOR FREEZING
RAIN THROUGH 12Z FRIDAY. A SATURATED ENVIRONMENT RIGHT AT THE
FREEZING MARK BRINGS CONCERNS FOR OVERALL GLAZING AMOUNTS...BUT AN
ADDITIONAL .1 TO .2 INCHES SEEMS REASONABLE. EASTERLY SURFACE
WINDS IN THE SAGINAW VALLEY HAVE BEEN NOTEWORTHY AND
CONCERNING...WITH 20 TO 30 KNOTS OF FLOW. SPORADIC POWER OUTAGES
WILL BE POSSIBLE. PRECIPITATION TYPE MAY TRY TO TRANSITION TO
LIGHT SNOW LATE...BUT GIVEN PERSISTENT TROWAL IN PLACE SUSPECT
THIS WILL BE DIFFICULT TO OCCUR BEFORE THE BACK EDGE OF THE
PRECIPITATION LIFTS NORTHWARD. WILL CONTINUE TO MONITOR AND UPDATE
THE FORECAST AS NEEDED.
PREV DISCUSSION...ISSUED 358 PM EDT THU APR 11 2013
SHORT TERM... THE REMAINDER OF TODAY THROUGH TONIGHT
THE FLOOD WATCH WILL REMAIN IN EFFECT THROUGH TONIGHT AFTER SOME
BRIEF CONSIDERATION OF DROPPING FOR THE TRI CITIES. DECIDED TO HOLD
ON THERE AS WELL GIVEN MODEL TRENDS THAT LOOK REASONABLE BRINGING
THE WESTERN FLANK OF THE NEXT MOISTURE SURGE THAT FAR NORTH AND WEST
INTO THE REGION. THE PATTERN WILL INCREASE STEADILY DURING THE REST
OF THE AFTERNOON THROUGH TONIGHT AS MOISTURE TRANSPORT, RESPONSIBLE
FOR THE OHIO VALLEY ACTIVITY, WORKS NORTHWARD THROUGH LOWER
MICHIGAN. THIS IS JUST A CLASSIC CASE OF MERIDIONAL UPPER JET
SUPPORT FOR A WELL ORGANIZED AGEOSTROPHIC CIRCULATION ALONG THE COLD
FRONT. STRONG GULF MOISTURE TRANSPORT THROUGH THE LOWER HALF OF THE
ATMOSPHERE WILL ENSURE THE RESULTING PATTERN OF SHOWERS IS INGESTED
INTO THE DEEP DIFFLUENT FLOW ALOFT OVER THE GREAT LAKES DURING THE
EVENING. EXPECT THE OCCLUSION PROCESS TO MATURE DURING THE OVERNIGHT
WHICH WILL CARRY THE TROWAL AXIS AS FAR NORTH AS THE TRI CITIES
AFTER MIDNIGHT AND THE TRAILING SURFACE TROUGH THAT FAR NORTH BY
SUNRISE FRIDAY. MODEL SOLUTIONS IN THIS REGARD LOOK GOOD AND SUPPORT
MAINTAINING THUS SUPPORT MAINTAINING THE FLOOD WATCH HEADLINE FOR
ALL AREAS AT LEAST UNTIL OBSERVATIONS CAN HELP REFINE THE WESTERN
EDGE OF THE RAIN SHIELD.
WHILE SHOWERS AND A RUMBLE OF THUNDER WILL BE THE MODE OF
PRECIPITATION FOR ALL AREAS TONIGHT, SURFACE TEMPERATURE TRENDS WILL
OTHERWISE BE MONITORED FOR PRECIPITATION TYPE CONSIDERATIONS IN THE
TRI CITIES AND NORTHERN THUMB. AS IT STANDS NOW, SURFACE TEMPERATURE
IS EXPECTED TO BE MODULATED UPWARD IN THAT AREA BY THE APPROACH OF
THE SURFACE TROUGH/OCCLUSION DURING THE EVENING AND THEN SOLIDLY
SUPPORTED ABOVE FREEZING OVERNIGHT. THERE IS A CHANCE OF WINTRY MIX
MENTIONED IN THE FORECAST MAINLY NORTH OF M-46 AS A BUFFER UP
AGAINST THE HIGHER POTENTIAL TAKING SHAPE IN NORTHERN LOWER
MICHIGAN.
LONG TERM...FRIDAY THROUGH WEDNESDAY
STRONG RIGHT ENTRANCE JET SUPPORT WILL RAPIDLY WANE DURING THE
MORNING HOURS AS THE LARGE UPPER LOW OVER THE CENTRAL CONUS LIFTS TO
THE NORTH AND JET FORCING IS SHUNTED WELL NORTH OF THE AREA. THE
ASSOCIATED INTENSITY DECLINE OF MOIST ISENTROPIC ASCENT AND
NORTHWARD ROTATION OF H85-H7 DEFORMATION LAYER WILL SPELL QUICKLY
DIMINISHING PRECIP CHANCES TO START THE PERIOD, AT LEAST AS FAR AS
ORGANIZED PRECIP. STILL TAPERED POPS DOWN S LOWLY, HOWEVER, GIVEN
THE PRESENCE OF THE ELONGATED SURFACE TROUGH INDICATED ON THE 12Z
NAM. DIURNAL HEATING ALONG WITH THE EXTRA BOOST OF LOW-LEVEL
CONVERGENCE IN THE PRESENCE OF LIGHT COLD ADVECTION & A MOIST
BOUNDARY LAYER WILL BE STRONGLY SUPPORTIVE FOR SOME REDEVELOPMENT OF
SHOWERS AS THE AXIS LIFTS NORTH THROUGH THROUGH EARLY AFTERNOON.
HOWEVER, EVEN AS ANY LINGERING DIURNAL ACTIVITY WANES LATE IN THE
DAY, ONGOING COLD ADVECTION THROUGH FRIDAY NIGHT SHOULD BE
SUFFICIENT TO MAINTAIN WELL-MIXED THERMAL PROFILES AND QUITE
POSSIBLY ANOTHER ROUND OF SURFACE-BASED SHOWER ACTIVITY,
PARTICULARLY AS A LOW AMPLITUDE PV ANOMALY ROTATES ACROSS THE STATE
DURING THE FIRST HALF OF THE NIGHT. CYCLONIC FLOW ALOFT WILL FOSTER
ANOTHER SHORTWAVE ACROSS THE STATE DURING THE DAY ON SATURDAY. THE
GENERAL MODEL CONSENSUS DEPICTS THE WAVE EVOKING WESTERLY WINDS AT
THE SURFACE AND REINFORCING THE EXISTING COLD AIRMASS AS H85 TEMPS
FALL TO AROUND -10C BY LATE IN THE DAY. CONVERGENT WESTERLY LOW
WITHIN THE BOUNDARY LAYER AND MODERATE COLD ADVECTION COMBINED WITH
MID APRIL SUN SHOULD BE QUITE FAVORABLE FOR A DIURNALLY ENHANCED
LAKE EFFECT SCENARIO. COLD THERMAL PROFILES APPEAR SUPPORTIVE FOR
SNOW WITHIN MOST SHOWERS. HIGHS WILL STRUGGLE OUT OF THE 30S DURING
PEAK HEATING.
MARINE...
STRONG NORTHEAST WIND WILL PERSIST TONIGHT OVER ALL MARINE AREAS AS
A LOW PRESSURE SYSTEM LIFTS INTO THE OHIO VALLEY AND EVENTUALLY INTO
CENTRAL LOWER MICHIGAN TONIGHT INTO FRIDAY. GALES REMAIN LIKELY
ACROSS THE NORTHERN HALF OF LAKE HURON AS THIS PROCESS COMMENCES AND
A GALE WARNING REMAINS IN EFFECT. THE PERSISTENT AND INCREASING
NORTHEAST FLOW WILL CAUSE WAVE HEIGHTS TO BUILD OVER SAGINAW BAY AND
THE LAKE HURON NEARSHORE WATERS OFF THE THUMB AND WILL RESULT IN AN
EXTENDED PERIOD OF ROUGH WATER THERE. IMPROVING CONDITIONS WITH
DIMINISHING WINDS AND WAVES WILL OCCUR FRIDAY INTO FRIDAY NIGHT AS
THE SYSTEM EXITS EASTWARD.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...FLOOD WATCH...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055-MIZ060-
MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075-MIZ076-MIZ082-
MIZ083...UNTIL 8 AM FRIDAY.
ICE STORM WARNING...MIZ047-MIZ048...UNTIL 8 AM FRIDAY.
LAKE HURON...
GALE WARNING...LHZ361-LHZ362-LHZ363-LHZ462...UNTIL 10 AM FRIDAY.
GALE WARNING...SAGINAW BAY AND THE NEARSHORE WATERS FROM PORT
AUSTIN TO HARBOR BEACH...UNTIL 4 AM FRIDAY.
SMALL CRAFT ADVISORY...NEARSHORE WATERS FROM HARBOR BEACH TO PORT
HURON...UNTIL 10 AM FRIDAY.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....SF
UPDATE.......CB
SHORT TERM...BT
LONG TERM....JVC
MARINE.......BT
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS RALEIGH NC
238 AM EDT FRI APR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL CROSS THE REGION TODAY. WEAK HIGH
PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 208 AM THURSDAY...
...ISOLATED THREAT FOR SEVERE WEATHER CONTINUES...
SYNOPTIC PICTURE: LARGE STACKED MID-UPPER LOW OVER IA WOBBLES NNE
THROUGH THE U.P. OF MI/LAKE SUPERIOR INTO ONTARIO THROUGH SATURDAY.
A SHORTWAVE TROUGH OVER GA/ERN TN OVERNIGHT WILL DAMPEN AS IT TRACKS
TO THE NE THROUGH NC THROUGH MIDDAY TODAY. AT THE SURFACE... AN
OCCLUDING FRONT WILL ROTATE UP THROUGH THE CENTRAL APPALACHIANS
TODAY WITH A TRAILING COLD FRONT SWEEPING EASTWARD THROUGH CENTRAL
NC BETWEEN 12Z-21Z. THIS FRONT WILL DISSIPATE OVER THE COASTAL PLAIN
BY 00Z... THEN A SECONDARY COLD FRONT WILL DROP SE THROUGH THE AREA
TONIGHT. WEAK HIGH PRESSURE CURRENTLY OVER THE HIGH PLAINS WILL
BUILD INTO THE WRN CAROLINAS FROM THE WEST ON SATURDAY.
THROUGH TODAY: SEVERE WEATHER THREAT PERSISTS FOR CENTRAL NC BUT
MANY QUESTIONS REMAIN. PROMINENT WELL-ORGANIZED SQUALL LINE FROM SW
VA THROUGH THE WRN CAROLINAS/ERN GA REMAINS RATHER POTENT... AND IS
WELL-SUPPORTED BY STRONG DYNAMIC FORCING FOR ASCENT INCLUDING MID
LEVEL DPVA AND INTENSE UPPER DIVERGENCE ASSOCIATED WITH A STRONG
SRLY JET STREAK OVER MI/IN/IL. BUT CLOUD TOP TEMPS HAVE BEEN
STEADILY WARMING IN THE LAST FEW HOURS... LIKELY DUE IN PART TO THE
SLOWLY WANING FORCING WITH THE WEAKENING WAVE AND JET STREAK. BOTH
THE INSTABILITY (ALBEIT MARGINAL) AND THE WIND FIELD (0-6 KM SHEAR
OF 40-50 KTS) HOWEVER REMAIN SUFFICIENT FOR MAINTENANCE OF THIS
CONVECTIVE LINE. ANOTHER BAND OF STORMS QUICKLY FORMING FROM AROUND
CAE DOWN TOWARD SAV IS IN A POCKET OF LOWER INSTABILITY WITH WEAK
CAPPING... BUT SHOULD PERSIST AND GROW UPSCALE AS IT ENCOUNTERS
BETTER INSTABILITY (MUCAPE NEAR 1000 J/KG) OVER THE SOUTHERN HALF OF
CENTRAL NC. CONVECTION-ALLOWING MODELS TAKE THIS CONVECTION NNE INTO
SOUTH CENTRAL/ERN NC WHILE BEING SLOWLY OVERTAKEN BY THE PRIMARY
SQUALL LINE. WHILE THE WEAKENING DYNAMICS ARE OF CONCERN... AS ARE
THE LOWERING MID LEVEL LAPSE RATES TO UNDER 6 C/KM... MODELS HOLD
ONTO MARGINAL INSTABILITY OF 500-1000 J/KG SBCAPE FOR THE NEXT 6
HOURS WHILE LOW LEVEL SHEAR REMAINS FORMIDABLE AT 35-40 KTS WITH
STRONGLY CURVING HODOGRAPHS ON RAP BUFR SOUNDINGS (ENHANCED BY
BACKING LOW LEVEL WINDS IN RESPONSE TO THE DEEPENING OCCLUDED
SURFACE LOW OVER WV/WRN VA ALONG WITH THE ARRIVAL OF THE 40-50 KT
SWRLY LOW LEVEL JET) TOWARD DAYBREAK. THIS SHOULD BE ENOUGH TO
SUPPORT A THREAT OF A FEW STRONG TO SEVERE CELLS WITH POSSIBLE
ROTATION... EITHER WITHIN THE MAIN SQUALL LINE OR IN THE PRECEDING
BAND... PRIMARILY FROM 06Z-14Z. DAMAGING WINDS AND ISOLATED
TORNADOES CONTINUE AS THE PRIMARY THREATS HERE. A SHORT LULL IN
STORM STRENGTH/ORGANIZATION IS LIKELY TO FOLLOW THIS MORNING WITH
THE DIMINISHING UPPER DIVERGENCE AND EXITING SHORTWAVE TROUGH. BUT
DEVELOPMENT OF ANOTHER LINE OF SCATTERED SHALLOW CONVECTION IS
EXPECTED BY AFTERNOON ALONG THE WEAKENING LEADING SURFACE FRONT...
ON THE LEADING EDGE OF THE INCOMING MID LEVEL DRY PUNCH. DESPITE
WANING LOW LEVEL MASS CONVERGENCE AND A FALLOFF OF LOW LEVEL SHEAR
AS SURFACE WINDS VEER TO SW AND WSW... THE RAP SHOWS SBCAPE
REBOUNDING TO 1000-1500 J/KG EAST OF HIGHWAY 1 THIS AFTERNOON WITH
LOW-MID LEVEL WINDS BECOMING UNIDIRECTIONAL GENERATING STRAIGHT-LINE
HODOGRAPHS. WILL RETAIN SCATTERED SHOWERS AND STORMS THROUGH THE
AFTERNOON IN THE EASTERN CWA... BECOMING MORE PATCHY AND SHALLOW
WITH CONTINUED DRYING ALOFT BY LATE AFTERNOON. HIGHS 77-84 AS
THICKNESSES HOLD IN THE 1375-1385 METER RANGE. STOUT WINDS FROM THE
SOUTH WILL BECOME MORE SSE THIS MORNING BEFORE SHIFTING TO SW BY
AFTERNOON.
FOR TONIGHT/SATURDAY: EXPECT A FEW LINGERING SHOWERS OVER THE
NORTHEAST SECTIONS THROUGH EARLY EVENING ALONG THE LEADING FRONT...
BUT OTHERWISE THE INCOMING DRIER AIR IN THE LOWEST 2-2.5 KM FAVORS A
WEST-TO-EAST CLEARING TREND DURING THE EVENING AS SURFACE WINDS
DIMINISH AND BECOME WEST THEN NW. WITH FALLING THICKNESSES AS THE
SECONDARY FRONT PASSES BY AND DECENT RADIATIONAL COOLING LIKELY...
HAVE NUDGED DOWN LOWS SLIGHTLY TO THE MID 40S TO LOW 50S. WEAK
SURFACE HIGH PRESSURE RIDGING FROM THE WEST AND LIGHT MAINLY
WESTERLY SURFACE FLOW WILL FOLLOW FOR SATURDAY. WE SHOULD SEE A FEW
HIGH CLOUDS STREAK ACROSS THE WRN/NRN SECTIONS EARLY SATURDAY
MORNING AS A WEAK MID LEVEL PERTURBATION MOVES NE OVER THE SRN
APPALACHIANS AND A 100-120 KT JETLET STREAKS BY TO OUR NNW... BUT
ASIDE FROM THIS WE SHOULD SEE PLENTY OF SUNSHINE WITH A FAIRLY DRY
COLUMN AS PW VALUES DROP TO NEAR OR JUST UNDER NORMAL. HIGHS 70-75.
-GIH
&&
.SHORT TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 230 AM FRIDAY...
WEAK HIGH PRESSURE MOVING OVER THE NORTHEASTERN US WILL EXTEND
SOUTH ACROSS THE CAROLINAS SUNDAY AS SHORTWAVE RIDGING DEVELOPS OVER
THE MID-ATLANTIC STATES AND GREAT LAKES REGION. LOW LEVEL
THICKNESSES SHOULD START OUT AROUND 1350M SUNDAY MORNING...WHICH IS
RIGHT AT NORMAL VALUES...AND HIGHS WILL ACCORDINGLY BE IN THE LOWER
70S MOST EVERYWHERE. A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE IS
FORECAST TO UNDERCUT THE RIDGE SUNDAY NIGHT AND TRACK EAST ACROSS
THE SOUTHEASTERN US THROUGH MONDAY. THIS WILL LIKELY LEAD TO A
CHANCE OF SHOWERS...MAINLY ACROSS THE SOUTH ON MONDAY BEFORE A MORE
PRONOUNCED MID/UPPER LEVEL RIDGE DEVELOPS BY TUESDAY. THE GFS NOW
SHOWS THE INVERTED COASTAL TROUGH THAT THE ECMWF HAS BEEN SHOWING IN
RECENT RUNS...DELAYING RETURN FLOW DEVELOPMENT AND KEEPING AN
EASTERLY COMPONENT TO THE LOW LEVEL FLOW WITH WEAKER MIXING BOTH
MONDAY AND TUESDAY. BECAUSE OF THIS...HAVE LOWERED HIGHS A COUPLE
OF DEGREES BOTH DAYS...WITH LOW/MID 70S MONDAY AND UPPER 70S
TUESDAY. LOWS IN THE LOWER 50S SUNDAY NIGHT AND MID 50S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 230 AM FRIDAY...
IN THE EXTENDED PERIOD...THE LONGWAVE PATTERN BECOMES QUITE SIMILAR
TO THE PATTERN OBSERVED THIS WEEK...WITH A RELOADING TROUGH OVER THE
WESTERN US AND RIDGING DOWNSTREAM OVER THE EASTERN US. THIS WILL
LEAD TO A RE-ESTABLISHMENT OF SOUTHERN RETURN FLOW AND TEMPS
CONTINUING TO CLIMB ABOVE NORMAL. THE GFS AND ECMWF THEN SHOW SOME
DISAGREEMENT ON HOW QUICKLY THE SYNOPTIC FRONT WILL TRANSLATE EAST
BY MID TO LATE WEEK. THE GFS SHOWS LESS OF A MID-LEVEL CAP AND MORE
INSTABILITY BY WEDNESDAY...PARTICULARLY OVER THE WESTERN CWA...WITH
THE RIDGE BREAKING DOWN MORE RAPIDLY. PREFER THE DRIER ECMWF WHICH
SEEMS TO FIT BETTER WITH PERSISTENCE AND THE REDEVELOPMENT OF THE
CURRENT PATTERN....KEEPING POPS OUT OF THE FORECAST UNTIL
THURSDAY/FRIDAY WHEN HEIGHTS MAY BEGIN TRULY TO FALL AHEAD A
SHORTWAVE LIFTING THROUGH THE MIDWEST STATES.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 200 AM FRIDAY...
MULTIPLE BANDS OF SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE
AREA OVERNIGHT IN ADVANCE OF AN UPPER LEVEL WAVE AND A SLOW MOVING
COLD FRONT APPROACHING FROM THE WEST. EXPECT PRIMARILY MVFR CEILINGS
WITH THE POTENTIAL FOR REDUCED IFR VISIBILITIES IN HEAVY RAIN.
STRONG THUNDERSTORM WIND GUSTS WILL ALSO BE POSSIBLE WITHIN THE
STRONGEST STORMS. THE STORMS WILL IMPACT WESTERN PORTIONS OF THE
FORECAST AREA (KGSO, KINT) BETWEEN 06-12Z AND THEN LOCATIONS FURTHER
EAST BETWEEN 09-15Z.
IN THE WAKE OF THE EXITING LINE OF STORMS FRIDAY MORNING...
STRONG DAYTIME HEATING SHOULD ALLOW FOR ANY SUB-VFR CEILINGS
TO LIFT TO VFR BY MIDDAY. A THIRD BAND OF SHOWERS AND STORM
COULD DEVELOP ACROSS THE AREA DURING THE AFTERNOON AS THE COLD
FRONT FINALLY PUSHES EAST THROUGH THE AREA...ESPECIALLY FROM
RDU EASTWARD. CONFIDENCE IN OCCURRENCE AND LOCATION IS RATHER LOW AT
THIS TIME AND WILL INCLUDE VCSH FOR NOW.
BREEZY CONDITIONS WILL CONTINUE THROUGHOUT MUCH OF THE PERIOD WITH
SOUTHERLY WINDS BECOME SOUTHWESTERLY FRIDAY AFTERNOON...WITH FREQUENT
GUSTS UP TO 20-25 KNOTS UNTIL FRONTAL PASSAGE LATE FRIDAY
AFTERNOON/EARLY FRIDAY EVENING.
OUTLOOK...VFR CONDITIONS WILL DOMINATE THROUGH THE WEEKEND AS HIGH
PRESSURE TAKES OVER. ANOTHER SYSTEM COULD BRING ANOTHER ROUND OF
ADVERSE AVIATION CONDITIONS TO THE REGION EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
230 AM EDT FRI APR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL CROSS THE REGION TODAY. WEAK HIGH
PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 208 AM THURSDAY...
...ISOLATED THREAT FOR SEVERE WEATHER CONTINUES...
SYNOPTIC PICTURE: LARGE STACKED MID-UPPER LOW OVER IA WOBBLES NNE
THROUGH THE U.P. OF MI/LAKE SUPERIOR INTO ONTARIO THROUGH SATURDAY.
A SHORTWAVE TROUGH OVER GA/ERN TN OVERNIGHT WILL DAMPEN AS IT TRACKS
TO THE NE THROUGH NC THROUGH MIDDAY TODAY. AT THE SURFACE... AN
OCCLUDING FRONT WILL ROTATE UP THROUGH THE CENTRAL APPALACHIANS
TODAY WITH A TRAILING COLD FRONT SWEEPING EASTWARD THROUGH CENTRAL
NC BETWEEN 12Z-21Z. THIS FRONT WILL DISSIPATE OVER THE COASTAL PLAIN
BY 00Z... THEN A SECONDARY COLD FRONT WILL DROP SE THROUGH THE AREA
TONIGHT. WEAK HIGH PRESSURE CURRENTLY OVER THE HIGH PLAINS WILL
BUILD INTO THE WRN CAROLINAS FROM THE WEST ON SATURDAY.
THROUGH TODAY: SEVERE WEATHER THREAT PERSISTS FOR CENTRAL NC BUT
MANY QUESTIONS REMAIN. PROMINENT WELL-ORGANIZED SQUALL LINE FROM SW
VA THROUGH THE WRN CAROLINAS/ERN GA REMAINS RATHER POTENT... AND IS
WELL-SUPPORTED BY STRONG DYNAMIC FORCING FOR ASCENT INCLUDING MID
LEVEL DPVA AND INTENSE UPPER DIVERGENCE ASSOCIATED WITH A STRONG
SRLY JET STREAK OVER MI/IN/IL. BUT CLOUD TOP TEMPS HAVE BEEN
STEADILY WARMING IN THE LAST FEW HOURS... LIKELY DUE IN PART TO THE
SLOWLY WANING FORCING WITH THE WEAKENING WAVE AND JET STREAK. BOTH
THE INSTABILITY (ALBEIT MARGINAL) AND THE WIND FIELD (0-6 KM SHEAR
OF 40-50 KTS) HOWEVER REMAIN SUFFICIENT FOR MAINTENANCE OF THIS
CONVECTIVE LINE. ANOTHER BAND OF STORMS QUICKLY FORMING FROM AROUND
CAE DOWN TOWARD SAV IS IN A POCKET OF LOWER INSTABILITY WITH WEAK
CAPPING... BUT SHOULD PERSIST AND GROW UPSCALE AS IT ENCOUNTERS
BETTER INSTABILITY (MUCAPE NEAR 1000 J/KG) OVER THE SOUTHERN HALF OF
CENTRAL NC. CONVECTION-ALLOWING MODELS TAKE THIS CONVECTION NNE INTO
SOUTH CENTRAL/ERN NC WHILE BEING SLOWLY OVERTAKEN BY THE PRIMARY
SQUALL LINE. WHILE THE WEAKENING DYNAMICS ARE OF CONCERN... AS ARE
THE LOWERING MID LEVEL LAPSE RATES TO UNDER 6 C/KM... MODELS HOLD
ONTO MARGINAL INSTABILITY OF 500-1000 J/KG SBCAPE FOR THE NEXT 6
HOURS WHILE LOW LEVEL SHEAR REMAINS FORMIDABLE AT 35-40 KTS WITH
STRONGLY CURVING HODOGRAPHS ON RAP BUFR SOUNDINGS (ENHANCED BY
BACKING LOW LEVEL WINDS IN RESPONSE TO THE DEEPENING OCCLUDED
SURFACE LOW OVER WV/WRN VA ALONG WITH THE ARRIVAL OF THE 40-50 KT
SWRLY LOW LEVEL JET) TOWARD DAYBREAK. THIS SHOULD BE ENOUGH TO
SUPPORT A THREAT OF A FEW STRONG TO SEVERE CELLS WITH POSSIBLE
ROTATION... EITHER WITHIN THE MAIN SQUALL LINE OR IN THE PRECEDING
BAND... PRIMARILY FROM 06Z-14Z. DAMAGING WINDS AND ISOLATED
TORNADOES CONTINUE AS THE PRIMARY THREATS HERE. A SHORT LULL IN
STORM STRENGTH/ORGANIZATION IS LIKELY TO FOLLOW THIS MORNING WITH
THE DIMINISHING UPPER DIVERGENCE AND EXITING SHORTWAVE TROUGH. BUT
DEVELOPMENT OF ANOTHER LINE OF SCATTERED SHALLOW CONVECTION IS
EXPECTED BY AFTERNOON ALONG THE WEAKENING LEADING SURFACE FRONT...
ON THE LEADING EDGE OF THE INCOMING MID LEVEL DRY PUNCH. DESPITE
WANING LOW LEVEL MASS CONVERGENCE AND A FALLOFF OF LOW LEVEL SHEAR
AS SURFACE WINDS VEER TO SW AND WSW... THE RAP SHOWS SBCAPE
REBOUNDING TO 1000-1500 J/KG EAST OF HIGHWAY 1 THIS AFTERNOON WITH
LOW-MID LEVEL WINDS BECOMING UNIDIRECTIONAL GENERATING STRAIGHT-LINE
HODOGRAPHS. WILL RETAIN SCATTERED SHOWERS AND STORMS THROUGH THE
AFTERNOON IN THE EASTERN CWA... BECOMING MORE PATCHY AND SHALLOW
WITH CONTINUED DRYING ALOFT BY LATE AFTERNOON. HIGHS 77-84 AS
THICKNESSES HOLD IN THE 1375-1385 METER RANGE. -GIH
&&
.SHORT TERM /SUNDAY THROUGH TUESDAY/...
AS OF 230 AM FRIDAY...
WEAK HIGH PRESSURE MOVING OVER THE NORTHEASTERN US WILL EXTEND
SOUTH ACROSS THE CAROLINAS SUNDAY AS SHORTWAVE RIDGING DEVELOPS OVER
THE MID-ATLANTIC STATES AND GREAT LAKES REGION. LOW LEVEL
THICKNESSES SHOULD START OUT AROUND 1350M SUNDAY MORNING...WHICH IS
RIGHT AT NORMAL VALUES...AND HIGHS WILL ACCORDINGLY BE IN THE LOWER
70S MOST EVERYWHERE. A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE IS
FORECAST TO UNDERCUT THE RIDGE SUNDAY NIGHT AND TRACK EAST ACROSS
THE SOUTHEASTERN US THROUGH MONDAY. THIS WILL LIKELY LEAD TO A
CHANCE OF SHOWERS...MAINLY ACROSS THE SOUTH ON MONDAY BEFORE A MORE
PRONOUNCED MID/UPPER LEVEL RIDGE DEVELOPS BY TUESDAY. THE GFS NOW
SHOWS THE INVERTED COASTAL TROUGH THAT THE ECMWF HAS BEEN SHOWING IN
RECENT RUNS...DELAYING RETURN FLOW DEVELOPMENT AND KEEPING AN
EASTERLY COMPONENT TO THE LOW LEVEL FLOW WITH WEAKER MIXING BOTH
MONDAY AND TUESDAY. BECAUSE OF THIS...HAVE LOWERED HIGHS A COUPLE
OF DEGREES BOTH DAYS...WITH LOW/MID 70S MONDAY AND UPPER 70S
TUESDAY. LOWS IN THE LOWER 50S SUNDAY NIGHT AND MID 50S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 230 AM FRIDAY...
IN THE EXTENDED PERIOD...THE LONGWAVE PATTERN BECOMES QUITE SIMILAR
TO THE PATTERN OBSERVED THIS WEEK...WITH A RELOADING TROUGH OVER THE
WESTERN US AND RIDGING DOWNSTREAM OVER THE EASTERN US. THIS WILL
LEAD TO A RE-ESTABLISHMENT OF SOUTHERN RETURN FLOW AND TEMPS
CONTINUING TO CLIMB ABOVE NORMAL. THE GFS AND ECMWF THEN SHOW SOME
DISAGREEMENT ON HOW QUICKLY THE SYNOPTIC FRONT WILL TRANSLATE EAST
BY MID TO LATE WEEK. THE GFS SHOWS LESS OF A MID-LEVEL CAP AND MORE
INSTABILITY BY WEDNESDAY...PARTICULARLY OVER THE WESTERN CWA...WITH
THE RIDGE BREAKING DOWN MORE RAPIDLY. PREFER THE DRIER ECMWF WHICH
SEEMS TO FIT BETTER WITH PERSISTENCE AND THE REDEVELOPMENT OF THE
CURRENT PATTERN....KEEPING POPS OUT OF THE FORECAST UNTIL
THURSDAY/FRIDAY WHEN HEIGHTS MAY BEGIN TRULY TO FALL AHEAD A
SHORTWAVE LIFTING THROUGH THE MIDWEST STATES.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 200 AM FRIDAY...
MULTIPLE BANDS OF SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE
AREA OVERNIGHT IN ADVANCE OF AN UPPER LEVEL WAVE AND A SLOW MOVING
COLD FRONT APPROACHING FROM THE WEST. EXPECT PRIMARILY MVFR CEILINGS
WITH THE POTENTIAL FOR REDUCED IFR VISIBILITIES IN HEAVY RAIN.
STRONG THUNDERSTORM WIND GUSTS WILL ALSO BE POSSIBLE WITHIN THE
STRONGEST STORMS. THE STORMS WILL IMPACT WESTERN PORTIONS OF THE
FORECAST AREA (KGSO, KINT) BETWEEN 06-12Z AND THEN LOCATIONS FURTHER
EAST BETWEEN 09-15Z.
IN THE WAKE OF THE EXITING LINE OF STORMS FRIDAY MORNING...
STRONG DAYTIME HEATING SHOULD ALLOW FOR ANY SUB-VFR CEILINGS
TO LIFT TO VFR BY MIDDAY. A THIRD BAND OF SHOWERS AND STORM
COULD DEVELOP ACROSS THE AREA DURING THE AFTERNOON AS THE COLD
FRONT FINALLY PUSHES EAST THROUGH THE AREA...ESPECIALLY FROM
RDU EASTWARD. CONFIDENCE IN OCCURRENCE AND LOCATION IS RATHER LOW AT
THIS TIME AND WILL INCLUDE VCSH FOR NOW.
BREEZY CONDITIONS WILL CONTINUE THROUGHOUT MUCH OF THE PERIOD WITH
SOUTHERLY WINDS BECOME SOUTHWESTERLY FRIDAY AFTERNOON...WITH FREQUENT
GUSTS UP TO 20-25 KNOTS UNTIL FRONTAL PASSAGE LATE FRIDAY
AFTERNOON/EARLY FRIDAY EVENING.
OUTLOOK...VFR CONDITIONS WILL DOMINATE THROUGH THE WEEKEND AS HIGH
PRESSURE TAKES OVER. ANOTHER SYSTEM COULD BRING ANOTHER ROUND OF
ADVERSE AVIATION CONDITIONS TO THE REGION EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS RALEIGH NC
208 AM EDT FRI APR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL CROSS THE REGION TODAY. WEAK HIGH
PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TODAY/...
AS OF 208 AM THURSDAY...
...ISOLATED THREAT FOR SEVERE WEATHER CONTINUES...
SYNOPTIC PICTURE: LARGE STACKED MID-UPPER LOW OVER IA WOBBLES NNE
THROUGH THE U.P. OF MI/LAKE SUPERIOR INTO ONTARIO THROUGH SATURDAY.
A SHORTWAVE TROUGH OVER GA/ERN TN OVERNIGHT WILL DAMPEN AS IT TRACKS
TO THE NE THROUGH NC THROUGH MIDDAY TODAY. AT THE SURFACE... AN
OCCLUDING FRONT WILL ROTATE UP THROUGH THE CENTRAL APPALACHIANS
TODAY WITH A TRAILING COLD FRONT SWEEPING EASTWARD THROUGH CENTRAL
NC BETWEEN 12Z-21Z. THIS FRONT WILL DISSIPATE OVER THE COASTAL PLAIN
BY 00Z... THEN A SECONDARY COLD FRONT WILL DROP SE THROUGH THE AREA
TONIGHT. WEAK HIGH PRESSURE CURRENTLY OVER THE HIGH PLAINS WILL
BUILD INTO THE WRN CAROLINAS FROM THE WEST ON SATURDAY.
THROUGH TODAY: SEVERE WEATHER THREAT PERSISTS FOR CENTRAL NC BUT
MANY QUESTIONS REMAIN. PROMINENT WELL-ORGANIZED SQUALL LINE FROM SW
VA THROUGH THE WRN CAROLINAS/ERN GA REMAINS RATHER POTENT... AND IS
WELL-SUPPORTED BY STRONG DYNAMIC FORCING FOR ASCENT INCLUDING MID
LEVEL DPVA AND INTENSE UPPER DIVERGENCE ASSOCIATED WITH A STRONG
SRLY JET STREAK OVER MI/IN/IL. BUT CLOUD TOP TEMPS HAVE BEEN
STEADILY WARMING IN THE LAST FEW HOURS... LIKELY DUE IN PART TO THE
SLOWLY WANING FORCING WITH THE WEAKENING WAVE AND JET STREAK. BOTH
THE INSTABILITY (ALBEIT MARGINAL) AND THE WIND FIELD (0-6 KM SHEAR
OF 40-50 KTS) HOWEVER REMAIN SUFFICIENT FOR MAINTENANCE OF THIS
CONVECTIVE LINE. ANOTHER BAND OF STORMS QUICKLY FORMING FROM AROUND
CAE DOWN TOWARD SAV IS IN A POCKET OF LOWER INSTABILITY WITH WEAK
CAPPING... BUT SHOULD PERSIST AND GROW UPSCALE AS IT ENCOUNTERS
BETTER INSTABILITY (MUCAPE NEAR 1000 J/KG) OVER THE SOUTHERN HALF OF
CENTRAL NC. CONVECTION-ALLOWING MODELS TAKE THIS CONVECTION NNE INTO
SOUTH CENTRAL/ERN NC WHILE BEING SLOWLY OVERTAKEN BY THE PRIMARY
SQUALL LINE. WHILE THE WEAKENING DYNAMICS ARE OF CONCERN... AS ARE
THE LOWERING MID LEVEL LAPSE RATES TO UNDER 6 C/KM... MODELS HOLD
ONTO MARGINAL INSTABILITY OF 500-1000 J/KG SBCAPE FOR THE NEXT 6
HOURS WHILE LOW LEVEL SHEAR REMAINS FORMIDABLE AT 35-40 KTS WITH
STRONGLY CURVING HODOGRAPHS ON RAP BUFR SOUNDINGS (ENHANCED BY
BACKING LOW LEVEL WINDS IN RESPONSE TO THE DEEPENING OCCLUDED
SURFACE LOW OVER WV/WRN VA ALONG WITH THE ARRIVAL OF THE 40-50 KT
SWRLY LOW LEVEL JET) TOWARD DAYBREAK. THIS SHOULD BE ENOUGH TO
SUPPORT A THREAT OF A FEW STRONG TO SEVERE CELLS WITH POSSIBLE
ROTATION... EITHER WITHIN THE MAIN SQUALL LINE OR IN THE PRECEDING
BAND... PRIMARILY FROM 06Z-14Z. DAMAGING WINDS AND ISOLATED
TORNADOES CONTINUE AS THE PRIMARY THREATS HERE. A SHORT LULL IN
STORM STRENGTH/ORGANIZATION IS LIKELY TO FOLLOW THIS MORNING WITH
THE DIMINISHING UPPER DIVERGENCE AND EXITING SHORTWAVE TROUGH. BUT
DEVELOPMENT OF ANOTHER LINE OF SCATTERED SHALLOW CONVECTION IS
EXPECTED BY AFTERNOON ALONG THE WEAKENING LEADING SURFACE FRONT...
ON THE LEADING EDGE OF THE INCOMING MID LEVEL DRY PUNCH. DESPITE
WANING LOW LEVEL MASS CONVERGENCE AND A FALLOFF OF LOW LEVEL SHEAR
AS SURFACE WINDS VEER TO SW AND WSW... THE RAP SHOWS SBCAPE
REBOUNDING TO 1000-1500 J/KG EAST OF HIGHWAY 1 THIS AFTERNOON WITH
LOW-MID LEVEL WINDS BECOMING UNIDIRECTIONAL GENERATING STRAIGHT-LINE
HODOGRAPHS. WILL RETAIN SCATTERED SHOWERS AND STORMS THROUGH THE
AFTERNOON IN THE EASTERN CWA... BECOMING MORE PATCHY AND SHALLOW
WITH CONTINUED DRYING ALOFT BY LATE AFTERNOON. HIGHS 77-84 AS
THICKNESSES HOLD IN THE 1375-1385 METER RANGE. -GIH
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
AS OF 250 PM THURSDAY...
THE COLD FRONT CLEARS THE COAST FRIDAY NIGHT WITH DRY WESTERLY FLOW
AND MILD HIGH PRESSURE BUILDING IN FOR THE WEEKEND. SKIES WILL BE
MOSTLY CLEAR WITH LITTLE IN THE WAY OF SENSIBLE WEATHER...MAINLY
JUST A TEMPERATURE FORECAST THROUGH THE PERIOD. THE COOLER AIRMASS
SETTLING INTO PLACE WILL BE EVIDENT SATURDAY MORNING WITH MORNING
MINIMUMS IN THE MID 40S WEST TO LOWER 50S EAST. PLENTIFUL SUNSHINE
ON BOTH SATURDAY AND SUNDAY WILL ALLOW HIGHS TO REACH A SEASONABLE
RANGE OF 70 TO 75. MEANWHILE...BEST RADIATIONAL CONDITIONS ARE
EXPECTED SATURDAY NIGHT DUE TO CALM WINDS...AND MINS SUNDAY MORNING
WILL BOTTOM OUT IN THE LOW AND MID 40S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 250 PM THURSDAY...
THE SURFACE HIGH PRESSURE MIGRATES OFFSHORE SUNDAY NIGHT...WITH
MOISTURE ADVECTION UNDERWAY AS SOUTHERLY LOW LEVEL FLOW INCREASES TO
20 TO 25 KNOTS. A WEAK SHORT WAVE WILL MOVE ALONG THE GULF COAST
SUNDAY NIGHT AS WELL...UTILIZING THE INCREASING MOISTURE TO PRODUCE
INCREASING CLOUD COVERAGE AND A CHANCE OF SHOWERS ACROSS THE AREA ON
MONDAY INTO MONDAY NIGHT. AT THIS POINT THE CHANCE FOR THUNDER LOOKS
MINIMAL DUE TO WEAK INSTABILITY AND LACK OF FOCUSED FORCING. MINS
SUNDAY NIGHT WILL BE MILD DUE TO THE CLOUDINESS AND SOUTHERLY
FLOW...IN THE LOWER 50S...WHILE HIGHS MONDAY WILL BE INHIBITED BY
THE CLOUDINESS AND TOP OUT IN THE MID TO PERHAPS UPPER 70S DESPITE
THE WARM START.
LOW AMPLITUDE RIDGING AND LOW LEVEL SOUTHERLY FLOW WILL PRODUCE A
WARMING TREND TUESDAY AND WEDNESDAY...WITH CAPPING ALOFT INHIBITING
CONVECTION TO ONLY ISOLATED AFTERNOON SHOWERS AS WE WARM INTO UPPER
70S TO LOWER 80S BOTH DAYS. TIMING OF A LATE WEEK COLD FRONT
APPROACHING FROM THE WEST IS IN QUESTION AS IT WILL DEPEND ON THE
RIDGE SHIFTING OFFSHORE RATHER QUICKLY...WILL INTRODUCE THURSDAYS
FORECAST WITH SMALL CHANCES OF SHOWERS IN THE WEST PENDING CONSENSUS
WITH LATER MODEL RUNS. HIGHS THURSDAY WILL BE AT LEAST IN THE 75 TO
80 DEGREE RANGE GIVEN WE WILL BE IN THE WARM SECTOR AHEAD OF THE
FRONT...AND COULD EASILY BE IN THE 80 TO 85 RANGE IF UPPER RIDGING
DELAYS THE FRONTS PROGRESS.
&&
.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 200 AM FRIDAY...
MULTIPLE BANDS OF SHOWERS AND THUNDERSTORMS WILL MOVE THROUGH THE
AREA OVERNIGHT IN ADVANCE OF AN UPPER LEVEL WAVE AND A SLOW MOVING
COLD FRONT APPROACHING FROM THE WEST. EXPECT PRIMARILY MVFR CEILINGS
WITH THE POTENTIAL FOR REDUCED IFR VISIBILITIES IN HEAVY RAIN.
STRONG THUNDERSTORM WIND GUSTS WILL ALSO BE POSSIBLE WITHIN THE
STRONGEST STORMS. THE STORMS WILL IMPACT WESTERN PORTIONS OF THE
FORECAST AREA (KGSO, KINT) BETWEEN 06-12Z AND THEN LOCATIONS FURTHER
EAST BETWEEN 09-15Z.
IN THE WAKE OF THE EXITING LINE OF STORMS FRIDAY MORNING...
STRONG DAYTIME HEATING SHOULD ALLOW FOR ANY SUB-VFR CEILINGS
TO LIFT TO VFR BY MIDDAY. A THIRD BAND OF SHOWERS AND STORM
COULD DEVELOP ACROSS THE AREA DURING THE AFTERNOON AS THE COLD
FRONT FINALLY PUSHES EAST THROUGH THE AREA...ESPECIALLY FROM
RDU EASTWARD. CONFIDENCE IN OCCURRENCE AND LOCATION IS RATHER LOW AT
THIS TIME AND WILL INCLUDE VCSH FOR NOW.
BREEZY CONDITIONS WILL CONTINUE THROUGHOUT MUCH OF THE PERIOD WITH
SOUTHERLY WINDS BECOME SOUTHWESTERLY FRIDAY AFTERNOON...WITH FREQUENT
GUSTS UP TO 20-25 KNOTS UNTIL FRONTAL PASSAGE LATE FRIDAY
AFTERNOON/EARLY FRIDAY EVENING.
OUTLOOK...VFR CONDITIONS WILL DOMINATE THROUGH THE WEEKEND AS HIGH
PRESSURE TAKES OVER. ANOTHER SYSTEM COULD BRING ANOTHER ROUND OF
ADVERSE AVIATION CONDITIONS TO THE REGION EARLY NEXT WEEK.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...HARTFIELD
SHORT TERM...MLM
LONG TERM...MLM
AVIATION...CBL
AREA FORECAST DISCUSSION
NWS MIAMI FL
1008 AM EDT FRI APR 12 2013
.UPDATE...
THE MORNING SURFACE ANALYSIS SHOWED A COLD FRONT EXTENDING SOUTH
AND SOUTHWEST ACROSS THE FLORIDA BIG BEND TO THE CENTRAL GULF OF
MEXICO WITH MOIST SOUTHERLY FLOW ACROSS THE FLORIDA PENINSULA
AHEAD OF IT. LOCAL OBSERVATIONS SHOWED DEWPOINTS RANGING FROM 70
TO 75 DEGREES. THE MORNING SOUNDING HERE IN MIAMI WAS VERY MOIST
UP TO AROUND 650 MB (PWAT AT 2.03") WITH LIGHT TO MODERATE
SOUTHERLY FLOW THROUGH THE LOW/MID LAYERS. THE LATEST RADAR LOOP
SHOWED MAINLY ISOLATED/SCT SHOWERS SPREADING NORTH ALONG THE EAST
COAST OF BROWARD AND MIAMI-DADE COUNTIES. LATER IN THE
AFTERNOON/EVENING...THE PREVIOUSLY MENTIONED COLD FRONT WILL
CONTINUE TO ADVANCE EASTWARD TOWARD AND INTO CENTRAL FLORIDA. THIS
COMBINED WITH DAYTIME HEATING...PLENTY OF DEEP LAYER MOISTURE AND
THE AFTERNOON SEA BREEZES WILL BE ENOUGH TO SUPPORT SCATTERED
THUNDERSTORMS TODAY. THE BEST CHANCE FOR THESE STORMS WILL REMAIN
OVER THE NORTHERN AND EASTERN SECTIONS OF THE AREA...ESPECIALLY
OVER PALM BEACH COUNTY. THE LATEST HRRR AND WRF ARW MODEL
REFLECTIVITIES LINE UP WELL WITH THIS PATTERN AND INDICATE THE
AFTERNOON CONVECTION INITIATING AND CONCENTRATING OVER THE EAST
COAST FROM BROWARD TO PALM BEACH COUNTIES AFTER 16Z...THEN
TRENDING DOWN THROUGH MID-EVENING PERIOD. THE MAIN IMPACTS FROM
THESE STORMS WILL BE THE POTENTIAL FOR WET MICROBURSTS AND HEAVY
RAINFALL. THE EXPERIMENTAL WMSI INDEX FROM THE LOCALLY RUN WRFNMM
SB-CAPE AND SFC/MID-LEVEL THETA-E INDICATE WIND GUSTS FROM ANY
MICROBURST COULD REACH THE 35 TO 49 KT RANGE FROM ANY STRONG STORM
THAT DOES DEVELOP. FOR THE MORNING UPDATE...WE HAVE SLIGHTLY
INCREASED THE RAINFALL CHANCES TODAY OVER THESE EAST COAST
LOCATIONS MENTIONED. 85/AG
&&
.PREV DISCUSSION... /ISSUED 735 AM EDT FRI APR 12 2013/
AVIATION...
LATEST RADAR TRENDS SHOW AREAS OF DIMINISHING RAIN SHOWERS
PUSHING NORTH ACROSS INTERIOR AREAS EARLY THIS MORNING AS A MOIST
LOW LEVEL FLOW SURGES ACROSS THE AREA FROM THE GULF OF MEXICO.
SHOWERS SHOULD CONTINUE TO PUSH TO THE NORTH AND REDEVELOP THROUGH
THE EARLY MORNING HOURS ACCOMPANIED WITH GENERALLY MVFR CIGS FOR
ALL TAF SITES. CANNOT NOT RULE OUT AN ISOLATED IFR CIG FOR A BRIEF
PERIOD SOMETIME THIS MORNING ALONG WITH AN ISOLD TSRA BUT WILL
LEAVE OUT OF THE FORECAST AT THIS TIME. WINDS WILL MOSTLY REMAIN
SSE AND INCREASE THROUGH THE AFTERNOON AS A COLD FRONT APPROACHES
FROM THE NORTH. GULF SEA BREEZE WILL DEVELOP BY LATE THIS MORNING
SO THE THREAT FOR ADDITIONAL CONVECTION WILL REMAIN EAST OF THE
KAPF TERMINAL.
KOB/CD
PREV DISCUSSION... /ISSUED 540 AM EDT FRI APR 12 2013/
DISCUSSION...
CONDITION ARE BEGINNING TO CHANGE THIS MORNING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS IS THE FRONT WE HAVE BEEN EXPECTING
MOST OF THE WEEK. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
FRONT STALLING SOMEWHERE OVER CENTRAL FLORIDA. THIS IS DUE TO
STRONG HIGH PRESSURE TO THE EAST AND THE FACT THAT THE MAIN WILL
BE VERY QUICKLY MOVING TO THE NORTHEAST, TAKING MOST OF THE ENERGY
WITH IT. THERE IS AN AREA OF HIGH PRESSURE MOVING IN BEHIND THE
FRONT. THIS HIGH PRESSURE WILL MERGE WITH THE HIGH PRESSURE SYSTEM
TO THE EAST. AS IT DOES, IT WILL ALLOW FOR A PERIOD OF MOSTLY
QUIET WEATHER FOR NEXT WEEK. THERE WILL STILL BE A SMALL POTENTIAL
FOR AN AFTERNOON SHOWER OR AN ISOLATED THUNDERSTORM TO DEVELOP,
BUT THAT WILL BE MAINLY IN THE AFTERNOON, AND LOOKS TO DIMINISH
TOWARDS THE MIDDLE OF THE WEEK AT THIS TIME.
AS FOR THE DYNAMICS FOR TODAY AND TOMORROW. WELL, THERE IS TYPICAL
INSTABILITY IN PLACE FOR TODAY, AS WELL AS PLENTY OF MOISTURE.
MODELS ARE INDICATING SOME ISOLATED TO SCATTERED SHOWERS AND
POSSIBLY A THUNDERSTORM THIS AFTERNOON. THE HRRR PLACES MOST OF
THE ACTIVITY ALONG THE EAST COAST OF SOUTH FLORIDA. GIVEN THE
SOUTHWESTERLY FLOW, CAN NOT ARGUE AGAINST IT. SO, WHILE POPS ARE
ALL OVER THE CWA, THERE ARE SOME HIGH POPS IN THE NORTHEASTERN
PORTION OF SOUTH FLORIDA.
FOR TOMORROW, THE LONG ANTICIPATED COLD FRONT WILL MOVE INTO THE
FLORIDA PENINSULA. IT CURRENTLY LOOKS TO MAKE IT DOWN JUST ABOUT TO
LAKE OKEECHOBEE BEFORE STALLING. THIS WILL KEEP SOUTH FLORIDA IN
THE WARM SECTOR TOMORROW. THERE WILL ALSO BE A 100KT JET EXITING
CENTRAL FLORIDA, WITH THE TAIL END NEAR MELBOURNE AROUND 00Z
SUNDAY. THIS PLACES THE AREA NEAR LAKE OKEECHOBEE IN THE RIGHT
ENTRANCE REGION OF THE JET. THIS, COMBINED WITH THE SFC BOUNDARY
AND PLENTY OF CAPE, AROUND 1500 JOULES, WILL PROBABLY ALLOW SOME
THUNDERSTORMS TO DEVELOP. SOME OF THOSE STORMS MAY BE STRONG.
THESE WILL MOVE OFF TO THE EAST, ALONG WITH THE UPPER LEVEL
DYNAMICS BY SATURDAY EVENING. THE FRONT WILL DISSIPATE THROUGH THE
DAY ON SUNDAY.
MARINE...
HIGH PRESSURE HAS SHIFTED SLIGHTLY AHEAD OF A COLD FRONT. THIS
WILL CAUSE THE WINDS TO TURN TO THE SW OVER THE GULF TODAY. THE
WINDS OVER THE ATLANTIC WILL TURN MORE SOUTHERLY. THE COLD FRONT
WILL MOVE CLOSER TO SOUTH FLORIDA TONIGHT AND STALL ACROSS SOUTH
CENTRAL FLORIDA BY TOMORROW MORNING. THIS WILL ALLOW SHOWERS AND
THUNDERSTORMS TO DEVELOP THROUGH TOMORROW EVENING. THE FRONT WILL
DISSIPATE THROUGH THE DAY ON SUNDAY, ALLOWING FOR QUIETER WEATHER.
FIRE WEATHER...
THE MAIN CONCERNS WILL BE WIND AND THUNDERSTORMS TODAY AND
TOMORROW. THE WIND WILL TURN FROM THE SOUTHEAST TO BE OUT OF THE
SOUTHWEST TODAY AS HIGH PRESSURE TO THE EAST HAS SHIFTED SOMEWHAT
IN ADVANCE OF A COLD FRONT. THE WINDS ARE EXPECTED TO PICK UP TO
NEAR 15 MPH THIS AFTERNOON. THERE IS A CHANCE OF A THUNDERSTORM
TODAY, MAINLY NORTH OF I75.
BY TOMORROW, THE COLD FRONT WILL STALL OVER SOUTH CENTRAL FLORIDA.
THIS WILL ALLOW THUNDERSTORM DEVELOP ACROSS THE AREA, BUT MAINLY
IN THE LAKE REGION. SOME OF THE STORMS COULD BECOME STRONG. THE
FRONT WILL DISSIPATE THROUGH SUNDAY. QUIETER WEATHER CONDITIONS ARE
EXPECTED NEXT WEEK UNDER HIGH PRESSURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 73 84 72 / 40 20 50 20
FORT LAUDERDALE 84 74 84 74 / 40 20 50 20
MIAMI 85 74 84 74 / 30 20 40 20
NAPLES 82 70 82 69 / 30 20 40 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...30/KOB
AREA FORECAST DISCUSSION
NWS MIAMI FL
540 AM EDT FRI APR 12 2013
.DISCUSSION...
CONDITION ARE BEGINNING TO CHANGE THIS MORNING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS IS THE FRONT WE HAVE BEEN EXPECTING
MOST OF THE WEEK. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
FRONT STALLING SOMEWHERE OVER CENTRAL FLORIDA. THIS IS DUE TO
STRONG HIGH PRESSURE TO THE EAST AND THE FACT THAT THE MAIN WILL
BE VERY QUICKLY MOVING TO THE NORTHEAST, TAKING MOST OF THE ENERGY
WITH IT. THERE IS AN AREA OF HIGH PRESSURE MOVING IN BEHIND THE
FRONT. THIS HIGH PRESSURE WILL MERGE WITH THE HIGH PRESSURE SYSTEM
TO THE EAST. AS IT DOES, IT WILL ALLOW FOR A PERIOD OF MOSTLY
QUIET WEATHER FOR NEXT WEEK. THERE WILL STILL BE A SMALL POTENTIAL
FOR AN AFTERNOON SHOWER OR AN ISOLATED THUNDERSTORM TO DEVELOP,
BUT THAT WILL BE MAINLY IN THE AFTERNOON, AND LOOKS TO DIMINISH
TOWARDS THE MIDDLE OF THE WEEK AT THIS TIME.
AS FOR THE DYNAMICS FOR TODAY AND TOMORROW. WELL, THERE IS TYPICAL
INSTABILITY IN PLACE FOR TODAY, AS WELL AS PLENTY OF MOISTURE.
MODELS ARE INDICATING SOME ISOLATED TO SCATTERED SHOWERS AND
POSSIBLY A THUNDERSTORM THIS AFTERNOON. THE HRRR PLACES MOST OF
THE ACTIVITY ALONG THE EAST COAST OF SOUTH FLORIDA. GIVEN THE
SOUTHWESTERLY FLOW, CAN NOT ARGUE AGAINST IT. SO, WHILE POPS ARE
ALL OVER THE CWA, THERE ARE SOME HIGH POPS IN THE NORTHEASTERN
PORTION OF SOUTH FLORIDA.
FOR TOMORROW, THE LONG ANTICIPATED COLD FRONT WILL MOVE INTO THE
FLORIDA PENINSULA. IT CURRENTLY LOOKS TO MAKE IT DOWN JUST ABOUT TO
LAKE OKEECHOBEE BEFORE STALLING. THIS WILL KEEP SOUTH FLORIDA IN
THE WARM SECTOR TOMORROW. THERE WILL ALSO BE A 100KT JET EXITING
CENTRAL FLORIDA, WITH THE TAIL END NEAR MELBOURNE AROUND 00Z
SUNDAY. THIS PLACES THE AREA NEAR LAKE OKEECHOBEE IN THE RIGHT
ENTRANCE REGION OF THE JET. THIS, COMBINED WITH THE SFC BOUNDARY
AND PLENTY OF CAPE, AROUND 1500 JOULES, WILL PROBABLY ALLOW SOME
THUNDERSTORMS TO DEVELOP. SOME OF THOSE STORMS MAY BE STRONG.
THESE WILL MOVE OFF TO THE EAST, ALONG WITH THE UPPER LEVEL
DYNAMICS BY SATURDAY EVENING. THE FRONT WILL DISSIPATE THROUGH THE
DAY ON SUNDAY.
MARINE...
HIGH PRESSURE HAS SHIFTED SLIGHTLY AHEAD OF A COLD FRONT. THIS
WILL CAUSE THE WINDS TO TURN TO THE SW OVER THE GULF TODAY. THE
WINDS OVER THE ATLANTIC WILL TURN MORE SOUTHERLY. THE COLD FRONT
WILL MOVE CLOSER TO SOUTH FLORIDA TONIGHT AND STALL ACROSS SOUTH
CENTRAL FLORIDA BY TOMORROW MORNING. THIS WILL ALLOW SHOWERS AND
THUNDERSTORMS TO DEVELOP THROUGH TOMORROW EVENING. THE FRONT WILL
DISSIPATE THROUGH THE DAY ON SUNDAY, ALLOWING FOR QUIETER WEATHER.
FIRE WEATHER...
THE MAIN CONCERNS WILL BE WIND AND THUNDERSTORMS TODAY AND
TOMORROW. THE WIND WILL TURN FROM THE SOUTHEAST TO BE OUT OF THE
SOUTHWEST TODAY AS HIGH PRESSURE TO THE EAST HAS SHIFTED SOMEWHAT
IN ADVANCE OF A COLD FRONT. THE WINDS ARE EXPECTED TO PICK UP TO
NEAR 15 MPH THIS AFTERNOON. THERE IS A CHANCE OF A THUNDERSTORM
TODAY, MAINLY NORTH OF I75.
BY TOMORROW, THE COLD FRONT WILL STALL OVER SOUTH CENTRAL FLORIDA.
THIS WILL ALLOW THUNDERSTORM DEVELOP ACROSS THE AREA, BUT MAINLY
IN THE LAKE REGION. SOME OF THE STORMS COULD BECOME STRONG. THE
FRONT WILL DISSIPATE THROUGH SUNDAY. QUIETER WEATHER CONDITIONS ARE
EXPECTED NEXT WEEK UNDER HIGH PRESSURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 73 84 72 / 40 20 50 20
FORT LAUDERDALE 84 74 84 74 / 40 20 50 20
MIAMI 85 74 84 74 / 30 20 50 20
NAPLES 82 70 82 69 / 30 20 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS MIAMI FL
531 AM EDT FRI APR 12 2013
.DISCUSSION...
CONDITION ARE BEGINNING TO CHANGE THIS MORNING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS IS THE FRONT WE HAVE BEEN EXPECTING
MOST OF THE WEEK. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
FRONT STALLING SOMEWHERE OVER CENTRAL FLORIDA. THIS IS DUE TO
STRONG HIGH PRESSURE TO THE EAST AND THE FACT THAT THE MAIN WILL
BE VERY QUICKLY MOVING TO THE NORTHEAST, TAKING MOST OF THE ENERGY
WITH IT. THERE IS AN AREA OF HIGH PRESSURE MOVING IN BEHIND THE
FRONT. THIS HIGH PRESSURE WILL MERGE WITH THE HIGH PRESSURE SYSTEM
TO THE EAST. AS IT DOES, IT WILL ALLOW FOR A PERIOD OF MOSTLY
QUIET WEATHER FOR NEXT WEEK. THERE WILL STILL BE A SMALL POTENTIAL
FOR AN AFTERNOON SHOWER OR AN ISOLATED THUNDERSTORM TO DEVELOP,
BUT THAT WILL BE MAINLY IN THE AFTERNOON, AND LOOKS TO DIMINISH
TOWARDS THE MIDDLE OF THE WEEK AT THIS TIME.
AS FOR THE DYNAMICS FOR TODAY AND TOMORROW. WELL, THERE IS TYPICAL
INSTABILITY IN PLACE FOR TODAY, AS WELL AS PLENTY OF MOISTURE.
MODELS ARE INDICATING SOME ISOLATED TO SCATTERED SHOWERS AND
POSSIBLY A THUNDERSTORM THIS AFTERNOON. THE HRRR PLACES MOST OF
THE ACTIVITY ALONG THE EAST COAST OF SOUTH FLORIDA. GIVEN THE
SOUTHWESTERLY FLOW, CAN NOT ARGUE AGAINST IT. SO, WHILE POPS ARE
ALL OVER THE CWA, THERE ARE SOME HIGH POPS IN THE NORTHEASTERN
PORTION OF SOUTH FLORIDA.
FOR TOMORROW, THE LONG ANTICIPATED COLD FRONT WILL MOVE INTO THE
FLORIDA PENINSULA. IT CURRENTLY LOOKS TO MAKE IT DOWN JUST ABOUT TO
LAKE OKEECHOBEE BEFORE STALLING. THIS WILL KEEP SOUTH FLORIDA IN
THE WARM SECTOR TOMORROW. THERE WILL ALSO BE A 100KT JET EXITING
CENTRAL FLORIDA, WITH THE TAIL END NEAR MELBOURNE AROUND 00Z
SUNDAY. THIS PLACES THE AREA NEAR LAKE OKEECHOBEE IN THE RIGHT
ENTRANCE REGION OF THE JET. THIS, COMBINED WITH THE SFC BOUNDARY
AND PLENTY OF CAPE, AROUND 1500 JOULES, WILL PROBABLY ALLOW SOME
THUNDERSTORMS TO DEVELOP. SOME OF THOSE STORMS MAY BE STRONG.
THESE WILL MOVE OFF TO THE EAST, ALONG WITH THE UPPER LEVEL
DYNAMICS BY SATURDAY EVENING. THE FRONT WILL DISSIPATE THROUGH THE
DAY ON SUNDAY.
&&
.MARINE...
HIGH PRESSURE HAS SHIFTED SLIGHTLY AHEAD OF A COLD FRONT. THIS
WILL CAUSE THE WINDS TO TURN TO THE SW TODAY. THE COLD FRONT WILL
MOVE CLOSER TO SOUTH FLORIDA TONIGHT AND STALL ACROSS SOUTH
CENTRAL FLORIDA BY TOMORROW MORNING. THIS WILL ALLOW SHOWERS AND
THUNDERSTORMS TO DEVELOP THROUGH TOMORROW EVENING. THE FRONT WILL
DISSIPATE THROUGH THE DAY ON SUNDAY, ALLOWING FOR QUIETER WEATHER.
&&
.FIRE WEATHER...
THE MAIN CONCERNS WILL BE WIND AND THUNDERSTORMS TODAY AND
TOMORROW. THE WIND WILL TURN FROM THE SOUTHEAST TO BE OUT OF THE
SOUTHWEST TODAY AS HIGH PRESSURE TO THE EAST HAS SHIFTED SOMEWHAT
IN ADVANCE OF A COLD FRONT. THE WINDS ARE EXPECTED TO PICK UP TO
NEAR 15 MPH THIS AFTERNOON. THERE IS A CHANCE OF A THUNDERSTORM
TODAY, MAINLY NORTH OF I75.
BY TOMORROW, THE COLD FRONT WILL STALL OVER SOUTH CENTRAL FLORIDA.
THIS WILL ALLOW THUNDERSTORM DEVELOP ACROSS THE AREA, BUT MAINLY
IN THE LAKE REGION. SOME OF THE STORMS COULD BECOME STRONG. THE
FRONT WILL DISSIPATE THROUGH SUNDAY. QUIETER WEATHER CONDITIONS ARE
EXPECTED NEXT WEEK UNDER HIGH PRESSURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 73 84 72 / 40 20 50 20
FORT LAUDERDALE 84 74 84 74 / 30 20 50 20
MIAMI 85 74 84 74 / 30 20 50 20
NAPLES 82 70 82 69 / 30 20 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
626 AM EDT FRI APR 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION TOWARD MORNING. THE FRONT
WILL MOVE THROUGH THE AREA BY MIDDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT FOR THE WEEKEND. THERE WILL BE ANOTHER CHANCE FOR
RAIN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT MOVING INTO CENTRAL GEORGIA AT 1030Z. NARROW BAND OF
SHOWERS AHEAD OF FRONT. HIGH RESOLUTION MODELS AND RAP SUGGEST LOW
POPS THROUGH THE MORNING AS DEEPER MOISTURE IS SHIFTING EAST AND
NORTH OF THE REGION ALONG WITH STRONGER LIFT.
FRONT APPEARS SLOW TO MOVE THROUGH THE REGION SO PREFER WARMER
GUIDANCE WITH TEMPS MAXING OUT IN THE UPPER 70S TO LOWER 80S.
DECREASING CLOUDS BY MIDDAY...BECOMING MOSTLY SUNNY AND BREEZY FOR
A PERIOD THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
COLD AIR ADVECTION AND CLEAR SKIES BEHIND THE SYSTEM TONIGHT INTO
SATURDAY MORNING WILL LEAD TO NEAR NORMAL LOWS...IN THE UPPER 40S
TO LOWER 50S. FRONT WILL BE WELL OFF THE COAST BY SATURDAY MORNING
WITH HIGH PRESSURE BUILDING IN FROM THE WEST. COOLER AND DRIER
WEATHER ON SATURDAY WITH SEASONABLE TEMPERATURES IN THE MID TO
UPPER 70S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
NO SIGNIFICANT CHANGES MADE TO THE ONGOING FORECAST FOR THIS TIME
PERIOD. HIGH PRESSURE CENTERED NORTH OF THE FORECAST AREA WILL
DOMINATE SATURDAY NIGHT INTO SUNDAY. LOW PRESSURE OVER THE GULF WILL
MOVE NORTHEAST TOWARD THE REGION LATE SUNDAY INTO MONDAY INCREASING
MOISTURE AND CLOUD COVER. KEPT CHANCE OF POPS FOR MONDAY. SYSTEM
WILL SHIFT OFF THE COAST BY LATE MONDAY WITH AN UPPER RIDGE BUILDING
INTO THE AREA THROUGH WEDNESDAY. ECMWF AND GFS DISAGREE ON TIMING
AND MAGNITUDE OF SYSTEM TOWARD THE END OF THE WEEK. GFS HAS LOW
PRESSURE SYSTEM AND ASSOCIATED STRONG COLD FRONT MOVING THROUGH
THE AREA ON THURSDAY. ECMWF SHOWS A MUCH WEAKER SYSTEM THAT IS
SLOWER TO REACH THE AREA.
&&
.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
MVFR/IFR POSSIBLE AS SHOWER ACTIVITY MOVES OUT OF THE AREA..THEN VFR
THROUGH THE END OF THE PERIOD.
STILL SEEING A FEW SCATTERED RAIN SHOWERS IN THE NORTHERN PART OF
THE AREA...AND A LINE OF CONVECTIVE SHOWERS ALONG THE COLD FRONT TO
OUR WEST. OBSERVATIONS SHOW CEILINGS FLUCTUATING BETWEEN
VFR/MVFR/IFR. EXPECT SHOWER ACTIVITY WILL END AS THE FRONT MOVES
THROUGH THE AREA. CEILINGS WILL IMPROVE TO VFR BY LATE MORNING AND
REMAIN VFR THROUGH THE END OF THE TAF PERIOD. LATEST GFS LAMP
SHOWING A SIMILAR TREND. STRONG PRESSURE GRADIENT WILL GIVE WAY TO
SOUTHWESTERLY WINDS 10-15 KTS GUSTING TO 20-25 KTS FRIDAY AFTERNOON.
SKIES WILL CLEAR AS HIGH PRESSURE BUILDS IN FROM THE WEST AND THE
COLD FRONT SHIFTS EAST OF THE AREA TOWARD THE COAST. WINDS WILL
DECREASE DURING THE EVENING HOURS AND REMAIN WEST AROUND 5-7 KTS
OVERNIGHT WITH CLEAR SKIES.
EXTENDED AVIATION OUTLOOK...PERIODS OF MVFR CIGS WITH SCATTERED
CONVECTION POSSIBLE SUNDAY NIGHT AND INTO MONDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS JACKSON KY
655 AM EDT FRI APR 12 2013
.UPDATE...
ISSUED AT 655 AM EDT FRI APR 12 2013
COLD FRONT IS JUST ABOUT TO PUSH EAST OF PIKE COUNTY WITH ALL OF THE
AREA NOW SEEING TEMPERATURES FALL FAIRLY QUICKLY ALONG WITH
DEWPOINTS. SOME MID 40 TEMPERATURES ALREADY SHOWING UP ACROSS MUCH OF
CENTRAL KENTUCKY. SOME DRIZZLE HAS PERSISTED BEHIND THE DEPARTING
FRONT WITH JUST ENOUGH LOW LEVEL MOISTURE TRAPPED BELOW THE LOW LEVEL
INVERSION. THIS DRIZZLE SHOULD BE SHORT LIVED THIS MORNING AS
CEILINGS INCREASE BY MID MORNING. RUC NOW SHOWS CLOUDS HANGING ON FOR
MOST OF THE DAY...WHILE THE NAM CONTINUES TO SHOW LOW CLOUDS
DISSOLVING. GIVEN LATEST SATELLITE TRENDS...OUR WESTERN COUNTIES MAY
BE CLEARING OUT SHORTLY. GIVEN THE WIND FLOW IS NOT FAVORABLE FOR LOW
CLOUDS HANGING IN TODAY...HAVE OPTED TO GO WITH A BIT FASTER CLEARING
HAVING SKIES GO MOSTLY SUNNY BY THIS AFTERNOON. LOW CLOUDS CAN
SOMETIMES BE TRICKY AND NAM DOES SHOW MORE CLOUDS MOVING IN LATER THIS
AFTERNOON. HOWEVER...AS OF RIGHT NOW...NOT MUCH UPSTREAM...SO OPTING
TO GO A LITTLE MORE OPTIMISTIC.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM EDT FRI APR 12 2013
COLD FRONT HAS REACHED THE I-75 CORRIDOR IN THE LAST HOUR AND WILL
CONTINUE TO PUSH EAST ACROSS THE AREA EARLY THIS MORNING...CLEARING
FAR EASTERN KENTUCKY AROUND DAYBREAK. COOLER AND DRIER AIR WILL
FILTER INTO THE AREA TODAY. WITH COLD ADVECTION DURING THE MORNING
HOURS...A SMALL CLIMB FROM MORNING LOWS IS ANTICIPATED. CLOUDS WILL
LIKELY HOLD ON LONGER THAN THE NAM SUGGEST...AND CLOSER TO THE RUC
SOLUTION. THIS HAS CLOUDS EVENTUALLY BREAKING UP BY EARLY AFTERNOON.
THIS WILL ALSO IMPACT THE TEMPERATURE CLIMB TODAY. WE SHOULD BE ABLE
TO AT LEAST REACH THE MID/UPPER 50S...WITH AREAS IN THE SOUTHWEST
POSSIBLY EXCEEDING 60 WITH MORE CLEARING.
HIGH PRESSURE WILL BUILD ACROSS THE AREA TONIGHT INTO TOMORROW WITH
SKIES GOING MOSTLY CLEAR. SHELTERED VALLEYS MAY DECOUPLE TONIGHT
LEADING TO READINGS AT LEAST INTO THE MID 30S. THIS SHOULD ALLOW FOR
SOME LIMITED FROST POTENTIAL TONIGHT. A QUIET SATURDAY IS ON TAP WITH
PLENTY OF SUNSHINE BOOSTING TEMPERATURES INTO THE 60S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 308 AM EDT FRI APR 12 2013
THE MODELS HAVE COME INTO BETTER AGREEMENT ALOFT THROUGH THE BREADTH
OF THE EXTENDED PORTION OF THE FORECAST. THEY ALL STILL TAKE THE
GREAT LAKES TROUGH EAST EARLY IN THE PERIOD ALLOWING FOR RISING
HEIGHTS OVER KENTUCKY THIS WEEKEND AND INTO THE FIRST PART OF NEXT
WEEK. THEY ALSO ALL HAVE VARIOUS REPRESENTATIONS OF A MINOR TROUGH
PASSING THROUGH THE SOUTHEAST PORTION OF THE NATION DURING THE LATTER
PART OF THE WEEKEND. THIS UNCONSOLIDATED WAVE MAY YET HAVE A
SENSIBLE IMPACT ON THE WEATHER OF EAST KENTUCKY INTO MONDAY MORNING
WITH THE NAM12 THE MOST BEARISH AND THE GFS/GEM RATHER BENIGN.
MEANWHILE...A MODERATELY STRONG CLOSED LOW WILL BE LIFTING NORTHEAST
THROUGH THE NORTHERN PLAINS WELL AWAY FROM OUR AREA. TO THE WEST OF
THIS...A DEEPENING NODE OF THE BROAD NORTHWESTERN TROUGH WILL DEVELOP
INTO A POTENT TROUGH IN ITS OWN RIGHT AND SLOWLY START TO COME EAST.
AS THIS FEATURE STRENGTHENS AND DROPS TOWARD THE FOUR CORNERS REGION
IT WILL HELP TO PUMP UP THE DOWNSTREAM RIDGE OVER THE SOUTHEAST
PORTION OF THE NATION INTO MIDWEEK. THE ECMWF AND GFS ARE IN REAL
GOOD AGREEMENT NOW WITH THE LATTER PORTION OF THE EXTENDED WHILE THE
GEM IS QUICKER AND FURTHER NORTH WITH ITS TROUGH. THIS TROUGH MOVES
INTO THE CENTRAL PLAINS ON THURSDAY WITH HEIGHT FALLS INBOUND FOR
KENTUCKY. GIVEN THE AGREEMENT OF THE PREFERRED MODELS WITH THIS WILL
FAVOR A BLENDED SOLUTION THROUGH THE EXTENDED.
SENSIBLE WEATHER WILL FEATURE A DRY AND COOL START TO THE WEEKEND
WITH PATCHY FROST POSSIBLE IN THE DEEPER VALLEYS OF EAST KENTUCKY
SUNDAY MORNING. HOWEVER...MODERATING HIGH PRESSURE MOVING OFF TO THE
EAST AND A RIDGE BUILDING ALOFT WILL ALLOW FOR A SOLID WARM UP TO
COMMENCE AND CONTINUE INTO MID WEEK. A WEAK SFC WAVE PASSING TO THE
SOUTH OF EAST KENTUCKY LATE SUNDAY NIGHT AND EARLY MONDAY MAY
TRIGGER SOME CONVECTION OVER SOUTHERN PARTS OF THE CWA. ONCE THIS
PASSES...EAST KENTUCKY WILL BE ON THE NORTHWEST FRINGE OF A LARGE
AREA OF HIGH PRESSURE ALLOWING FOR RETURN FLOW MOISTURE TO INVADE
FROM A RELATIVELY OPEN GULF OF MEXICO. THIS MOISTURE WILL SLOWLY
BUILD THROUGH THE WEEK IN THIS EARLY SUMMER-LIKE PATTERN AND RESULT
IN A DAILY CHANCE FOR MAINLY AFTERNOON AND EVENING SHOWERS OR
THUNDERSTORMS THROUGH WEDNESDAY. A BETTER CHANCE OF RAIN CAN BE
ANTICIPATED ON THURSDAY AS A DEEP AREA OF LOW PRESSURE LIFTS OUT OF
THE CENTRAL PLAINS AND MOVES TO THE NORTHERN GREAT LAKES. THIS WILL
DRAG A COLD FRONT INTO KENTUCKY HELPING TO FOCUS THE BUILT UP
MOISTURE. WITH THE BETTER CHANCES OF RAIN THURSDAY WILL LIKELY BREAK
THE TREND OF CLIMBING HIGHS FROM DAY TO DAY.
THE CR GRID LOAD CAME IN PRETTY DECENT...BUT DID NUDGE DOWN POPS ON
MONDAY GIVEN THE UNCERTAINTY AND ALSO FINE TUNED THEM LATER IN THE
EXTENDED MORE TOWARD THE 12Z ECMWF. ALSO MAKE SOME SIGNIFICANT
TERRAIN BASED ADJUSTMENTS FOR LOWS EACH NIGHT...ANTICIPATING DECENT
RIDGE TO VALLEY SPLITS THROUGHOUT THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 655 AM EDT FRI APR 12 2013
CEILINGS WILL IMPROVE THROUGH THE MORNING AS DRIER AIR SPREADS ACROSS
THE AREA IN THE WAKE OF A COLD FRONT. STILL SOME UNCERTAINTY
REGARDING CLOUD COVER LATER THIS AFTERNOON AND EVENING...BUT AS OF
RIGHT NOW...NOT MUCH UPSTREAM TO HANG ANY CONFIDENCE ON THIS CLOUD
COVER. WILL GO MORE OPTIMISTIC WITH THE FORECAST FOR NOW. ANY CLOUDS
THIS AFTERNOON SHOULD REMAIN REMAIN AT OR ABOVE 5KFT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS GAYLORD MI
1023 AM EDT FRI APR 12 2013
.SYNOPSIS...
ISSUED AT 350 AM EDT FRI APR 12 2013
SLOW MOVING...LOW PRESSURE IS LIFTING INTO THE UPPER GREAT LAKES
REGION AND WILL BRING A WINTRY MESS OF PRECIPITATION TYPES TO
NORTHERN MICHIGAN TODAY. THE FREEZING RAIN AND SLEET IS EXPECTED TO
TRANSITION OVER TO SNOW AND DRIZZLE THIS MORNING. THIS WILL CONTINUE
INTO THE EVENING BEFORE CHANGING TO ALL SNOW TONIGHT. HIGH PRESSURE
TRIES TO SNOW INTO THE REGION ON SATURDAY SO THAT WE WILL GET A
BREAK FOR THE WEEKEND.
&&
.UPDATE...
ISSUED AT 1022 AM EDT FRI APR 12 2013
MAIN BATCH OF "WARM CONVEYOR" PRECIP HAS LIFTED NORTH/EAST OUT OF
THE CWA THIS MORNING...WHILE MID LEVEL DRY SLOT HAS PUNCHED UP
INTO NRN MICHIGAN (EVIDENT ON KAPX VAD WIND PROFILE). MAINLY JUST
SOME FLURRIES/DRIZZLE/FREEZING DRIZZLE OCCURRING AT THE MOMENT.
MAIN MID LEVEL SHORT WAVE SLOWLY ADVANCING NORTHEASTWARD ACROSS
WISCONSIN AND IS PRODUCING SOME ADDITIONAL LIGHT PRECIP THAT WILL
LIKELY IMPACT PARTS OF NORTHWEST LOWER AND EASTERN UPPER MICHIGAN
AS WE GO THROUGH THE AFTERNOON/EARLY EVENING. BUT OTHERWISE...MAIN
BATCH OF PRECIP IS DONE AND WINDS ARE WEAKENING. SO...WILL CANCEL
THE WINTER STORM WARNING FOR EASTERN UPPER MICHIGAN AHEAD OF
SCHEDULE.
UPDATE
ISSUED AT 712 AM EDT FRI APR 12 2013
ONGOING FORECAST IS PORTRAYING THE SCENE OUTSIDE PRETTY WELL. MAIN
SWATH OF PRECIPITATION IS WRAPPED FROM NE LOWER ACROSS EASTERN
UPPER. WITH COOLING OCCURRING THROUGHOUT THE ATMOSPHERE NOW...MOST
ALL AREAS HAVE SWITCHED OVER TO SNOW...OR LIGHT SNOW AND DRIZZLY
CONDITIONS UNDERNEATH DEEPER MOISTURE PEELING OFF TO THE EAST.
LATEST SATELLITE AND UPSTREAM SFC OBS SHOWING THAT EVERYONE IS
LIKELY TO GET INTO A PERIOD OR TWO OF DRIZZLE/FREEZING DRIZZLE. THE
WORST OF IT IS OVER NOW...AND WILL CANCEL THE WARNINGS FOR ALL BUT
EASTERN UPPER...WHERE SOME ADDITIONAL ACCUMULATIONS ARE
POSSIBLE...BUT EVEN HERE...DAY CREW MAY DECIDE TO END THE HEADLINES
BY LATE MORNING.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 350 AM EDT FRI APR 12 2013
CURRENTLY...POTENT UPPER LEVEL CLOSED LOW IS DRIFTING ACROSS THE
FAR NRN MISSISSIPPI VALLEY...WITH OCCLUDED LOW PRESSURE FROM THE
APPALACHIANS...AND TROUGHING/TROWAL EXTENDING BACK INTO SRN
WISCONSIN. MAIN H8-H7 WARM ADVECTION EXTENDS ALONG H8 WIND SPEED
MAX WHICH IS NOW EXTENDING FROM THE EASTERN GREAT LAKES BACK AROUND
THROUGH EASTERN UPPER MICHIGAN. THIS IS WHERE ONE SWATH OF BETTER
PRECIPITATION...IN THE FORM OF SNOW AND SOME SLEET...IS CO-LOCATED
WITH STRONG POCKET OF UPPER DIVERGENCE IN RIGHT ENTRANCE REGION OF
QUEBEC 120+KT UPPER JET. ANOTHER JET STREAK WAS CROSSING THE OHIO
RIVER VALLEY...AND ANOTHER POCKET OF UPPER DIVERGENCE IN LEFT EXIT
REGION OF WAS DEVELOPING ACROSS THE EASTERN GREAT LAKES. DPVA
AROUND THE CLOSED LOW ALOFT...COMBINED WITH THESE FORCING
MECHANISMS...HAS RESULTED IN MODEST TO STRONG DEEP LAYER LIFT AND
WIDESPREAD PRECIPITATION ACROSS MAINLY NE LOWER AND BACK AROUND
THROUGH EASTERN UPPER.
NOW...THERMALLY SPEAKING...WE HAVE GONE THROUGH QUITE ALONG PERIOD
OF SLEET AND FREEZING RAIN IN NRN LOWER...AS 00Z APX SOUNDING TELLS
THE STORY. 800-700MB DEEP 2-3C WARM NOSE IS EVIDENT...WITH A
COUNTERING DEEP SFC-800MB COLD LAYER WITH A MAXIMUM -6C READING AT
900MB...COLD ENOUGH TO RE-FREEZE TOTALLY MELTED DROPS FROM THAT 2-3C
DEEP WARM NOSE. ONE OF THE BETTER SLEET SOUNDINGS THIS FORECASTER
HAS SEEN. AS THE ENTIRE SYSTEM HAS BEEN SLOW TO TRANSITION NORTH AND
EAST WITH TIME...QUITE A BIT OF SLEET HAS BEEN ABLE TO FALL AND
ACCUMULATE. ACROSS EASTERN UPPER...SOME SLEET MAY BE TRYING TO MIX
WITH WHAT SHOULD BE PRIMARILY SNOW...BASED ON LATEST DUAL POL RADAR
LOOPING. RUC FCST SOUNDINGS ALSO SUGGEST ALL SNOW IN EASTERN
UPPER...WITH THE ELEVATED WARM COOLING STARTING AS OF THIS WRITING.
LATEST OBS SUGGESTING THAT THIS MAY BE TAKING PLACE NOW WITH MORE
OBSERVATIONS ACROSS THE WEST NOW LOOKING MORE "SNOWY" RATHER THAN
"ICY". ALSO IN THE MIX...IS THE CURRENT EFFORT FOR DEEPER MOISTURE
TO STRIP OUT ALOFT FROM THE WEST...WHICH ALLOWS US TO EXPERIENCE YET
ANOTHER PRECIPITATION TYPE...DRIZZLE AND FREEZING DRIZZLE.
IT SHOULD BE WORTH NOTING THAT NOT ALL FOLKS HAVE EXPERIENCED THIS
PLETHORA OF NASTY WINTRY WEATHER. DOWNSLOPING REGIONS ACROSS NW
LOWER...MAINLY FRANKFORT AND MANISTEE AREAS...WERE ABOVE FREEZING
FOR MUCH OF THE NIGHT...SO NOT FREEZING RAIN THERE.
IN THE SPIRIT OF A FORMER NWS COLLEAGUE..."WELL...AT LEAST IT`S
WINDY". YEAH...EAST WINDS WERE GUSTING AS HIGH AS 35-40 MPH MUCH OF
THE NIGHT TOO.
NOW...THE FORECAST...POTENT UPPER LOW WILL LIFT INTO EASTERN LAKE
SUPERIOR TODAY AND TONIGHT...WITH THE SFC TROUGHING/TROWAL AND
AXIS OF DEEPER MOISTURE AND FORCING LIFTING NORTH AND EAST
THROUGH THE MORNING. COLDER AIR SEEPS IN...AND THE TRANSITION OVER
TO MAINLY LIGHT SNOW WILL BE JOINED BY DRIZZLE AND FREEZING
DRIZZLE DUE TO DRYING ALOFT. THE THERMAL PROFILES BECOME AN
INCREASINGLY LIGHT SNOW/DRIZZLE LOOK...AS MOISTURE WILL BE AT OR
BELOW 10C FOR MOST OF THE DAY AND EVEN INTO THE EVENING. THE BEST
MOISTURE/FORCING WILL BE ACROSS CHIPPEWA COUNTY FOR THE LONGEST
PERIOD OF TIME. HERE...ALTHOUGH TOTAL QPF/SNOWFALL WERE LOWERED
SLIGHTLY...WILL STILL SEE A GRAND TOTAL OF 4 TO 8 INCHES BY THE
END OF THE DAY. LESSER AMOUNTS HEADING SOUTH UNTIL JUST AN INCH
DOWN NEAR THE M-55 CORRIDOR. CURRENT WINTER STORM HEADLINES WILL
HOLD TRUE...ENDING FROM SOUTH TO NORTH THROUGH THE DAY. LIGHT
SNOWS AND DRIZZLE ARE LIKELY AT LEAST INTO THE EVENING DUE TO THE
LOW LEVEL CONVERGENCE ASSOCIATED WITH THE ACTUAL SFC TROUGHING.
EVENTUALLY BY LATER TONIGHT...THE LOW LEVEL TROUGHING
WEAKENS/DEPARTS...WITH THE ENTIRE ATMOSPHERIC COLUMN COLD ENOUGH
FOR JUST SNOW. CAN MAKE A REAL GOOD ARGUMENT FOR LIKELY SNOWS FOR
MOST EVERYONE AT SOME POINT DURING THE NIGHT. THIS DUE NOT ONLY TO
THE LINGERING TROUGHING AT THE SFC...BUT ALSO WITH MID LEVEL
TROUGHING WITH THE UPPER CIRCULATIONS...WHICH WILL BE ALIGNED
ACROSS EASTERN UPPER. THUS...WILL HAVE THE BETTER ACCUMULATIONS
AND CHANCES FOR SNOW THERE. MAYBE ANOTHER INCH ACROSS EASTERN
UPPER...WITH LESSER AMOUNTS HEADING FURTHER SOUTH.
CLOUDY THROUGH THE PERIOD WITH LITTLE DIURNAL SWINGS IN
TEMPERATURE. HIGHS IN THE 30S TODAY...WITH LOWS IN THE MIDDLE 20S
TO LOWER 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM EDT FRI APR 12 2013
SATURDAY...AS THE 500 MB LOW DRIFTS EAST JUST NORTH OF THE FORECAST
AREA, THERE WILL BE ENOUGH FORCING TO CONTINUE THE SNOW SHOWERS.
HOWEVER, THE KICKER IS THAT THE 850 MB TEMPERATURES FALL TO AROUND
-10C AND WITH THE WATER TEMPERATURES SLIGHTLY WARMER AROUND +1 TO
+2C WE WILL PROBABLY GET SOME ENHANCEMENT ESPECIALLY NEARER THE SFC
AND 500 MB LOWS. SO WILL HAVE AN AREA OF LIKELY POPS IN E UPPER AND
ENHANCED CHANCE POPS IN NW LOWER. BY 00Z, THINGS BEGIN TO LOOK LIKE
LAKE EFFECT, HOWEVER, THE PROBLEM IS THAT THE 850 MB TEMPERATURES
BEGIN TO WARM BIT, AND WE LOSE THE ENHANCEMENT.
SATURDAY NIGHT...WE LOSE GOOD 850 MB AND SFC FLOW AS THE
TEMPERATURES RISE TO AROUND -8C. WILL ALLOW FOR SOME FLURRIES EARLY,
BUT ALL THINGS BEING EQUAL, THINK THAT THE WITH THE DRIER AIR MOVING
IN AS WELL, THAT THE SNOW WILL STOP SHORTLY HAVE 00Z.
SUNDAY...THE NEXT SYSTEM BEGINS TO LIFT NORTH INTO NORTHERN PLAINS.
THE GFS HAS IT A LITTLE MORE EAST IN MINNESOTA, WHILE THE 00Z ECMWF
HAS IT IN E NORTH DAKOTA. THE DIFFERENCE IS THAT THE GFS BRINGS
CHANCE POPS INTO NW LOWER SOONER. WITH THESE SYSTEMS BEING KIND OF
ALL OVER THE PLACE, IN THE RUN UP TO THEM, WILL HEDGE BETWEEN THE
TWO. SO CUT THE POPS BACK SO THAT NW LOWER HAVE SOME CHANCE POPS,
AND THE REST OF THE REGION IS RELATIVELY DRY. OVERNIGHT, THE WARM
FRONT IN EITHER CASE MAKES IT FAR ENOUGH NORTH RAIN TAKES OVER IN E
UPPER. THE FRONT STALLS THERE AS WELL SO THAT THE SFC LOW RIDES UP
INTO LAKE SUPERIOR ALONG IT. SO RAIN WILL BE EXPECTED IN E UPPER AND
WITH THE WARM SECTOR MOVING NORTH WILL HAVE LESS CHANCES TO THE
SOUTH.
EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, EXPECTING RAIN FROM THE
SYSTEM MOVING THROUGH DURING THE DAY. OVERNIGHT, WITH THE FRONT
THROUGH AND THE SFC LOW TO THE EAST, WILL EXPECT THAT E UPPER AND
PORTIONS OF N LOWER WILL CLEAR OUT AS HIGH PRESSURE BUILDS INTO THE
REGION. TUESDAY, THE FRONT HOLDS TO THE EAST WITH HIGH PRESSURE
NOSING INTO LOWER MICHIGAN. LOOKS LIKE SOME RAIN COULD HOLD ON WITH
WAVES RUNNING UP THE FRONT. SO WILL ALLOW FOR SOME RAIN IN NE
LOWER. WEDNESDAY, THE NEXT SYSTEM BEGINS TO PUSH OUT OF THE SOUTHERN
PLAINS AND BY THE TIME THAT IT GETS INTO THE MID-MISSISSIPPI VALLEY,
THE RAIN WILL SPREAD BACK NORTH THROUGH N LOWER AND IN E UPPER,
WHERE A MIX WILL BE EXPECTED. OF COURSE, THE WARM AIR WILL CONTINUE
NORTH CHANGING THE SNOW BACK TO RAIN OVERNIGHT. THURSDAY, THE MODELS
HAVE TWO DIFFERENT TRACKS. THE ECMWF STILL BRINGS THE SFC LOW OVER N
LOWER, WHICH WOULD BRING MORE RAIN TO THE REGION BEFORE CHANGING TO
SNOW THURSDAY NIGHT. THE GFS BRINGS THE SFC LOW UP THROUGH LAKE
ERIE. THIS WOULD BRING SNOW OR RAIN AND SNOW TO N LOWER AND E UPPER.
DECIDED TO PLAY AS RAIN THURSDAY, RAIN/SNOW THURSDAY NIGHT FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 712 AM EDT FRI APR 12 2013
WIDESPREAD MVFR CIGS WILL PREVAIL THROUGHOUT THE TAF PERIOD WITH
LOADS OF LOW LEVEL MOISTURE SURROUNDING LOW PRESSURE LIFTING THROUGH
NRN MICHIGAN TODAY. MOISTURE IS QUICKLY PEELING OUT ALOFT EARLY IN
THE TAF PERIOD WHILE TEMPERATURES ARE COOLING THROUGHOUT THE
ATMOSPHERE. THIS IS RESULTING IN A TRANSITION TO A SCENARIO
CHARACTERIZED AS PERIODS OF LIGHT SNOW AND DRIZZLE/FREEZING DRIZZLE.
THIS WILL BE THE COMMON THEME INTO THE EVENING...BEFORE ONLY LIGHT
SNOW SHOWERS ARE GOING TO BE POSSIBLE FOR THE LATE NIGHT HOURS.
GUSTY EAST WINDS TO 30 MPH AT PLN/APN WILL DIE OFF THROUGH THE
DAY...JUST AS THEY DID ACROSS MBL AND TVC. THESE WINDS WILL
GRADUALLY BACK AROUND OUT OF THE NORTH AND ULTIMATELY THE WEST BY
SATURDAY MORNING...AS THE LOW PRESSURE EXITS FURTHER EAST.
&&
.MARINE...
ISSUED AT 350 AM EDT FRI APR 12 2013
GALE FORCE GUSTS ARE IN FULL EFFECT ACROSS MOST OF THE SURROUNDING
NEARSHORE WATERS OF LAKES HURON AND MICHIGAN...NORTH OF GRAND
TRAVERSE LIGHT AND STURGEON POINT LIGHT. NORTH OF THERE...SOLID
ADVISORY LEVEL GUSTS WERE ONGOING...WHILE SOUTH OF THE
GALES...WINDS WERE DROPPING OFF RATHER QUICKLY WITH A LOOSE
GRADIENT ALONG LOW PRESSURE LIFTING NORTHWARD. THIS LIGHTER
GRADIENT WILL GRADUALLY OVERTAKE ALL OF THE NEARSHORE WATERS
THROUGH THE DAY...WITH GALES GRADUALLY STEPPING DOWN INTO
ADVISORY...THEN SUB ADVISORY LEVELS. THE LOW PRESSURE LIFTS EAST
TONIGHT...WITH COLD ADVECTION AND WESTERLY WINDS DEVELOPING...BUT
EXPECTATIONS ARE FOR WINDS TO BE BELOW ADVISORY LEVELS THROUGH
EARLY SUNDAY. THE NEXT LOW PRESSURE SYSTEM IS SET FOR LATER SUNDAY
AND INTO MONDAY. ADDITIONAL HEADLINES MAY BE REQUIRED.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ349.
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LHZ345>348.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-341-
344.
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LMZ342.
LS...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ321-322.
&&
$$
UPDATE...BA
SYNOPSIS...JL
SHORT TERM...SD
LONG TERM...JL
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS GAYLORD MI
713 AM EDT FRI APR 12 2013
.SYNOPSIS...
ISSUED AT 350 AM EDT FRI APR 12 2013
SLOW MOVING...LOW PRESSURE IS LIFTING INTO THE UPPER GREAT LAKES
REGION AND WILL BRING A WINTRY MESS OF PRECIPITATION TYPES TO
NORTHERN MICHIGAN TODAY. THE FREEZING RAIN AND SLEET IS EXPECTED TO
TRANSITION OVER TO SNOW AND DRIZZLE THIS MORNING. THIS WILL CONTINUE
INTO THE EVENING BEFORE CHANGING TO ALL SNOW TONIGHT. HIGH PRESSURE
TRIES TO SNOW INTO THE REGION ON SATURDAY SO THAT WE WILL GET A
BREAK FOR THE WEEKEND.
&&
.UPDATE...
ISSUED AT 712 AM EDT FRI APR 12 2013
ONGOING FORECAST IS PORTRAYING THE SCENE OUTSIDE PRETTY WELL. MAIN
SWATH OF PRECIPITATION IS WRAPPED FROM NE LOWER ACROSS EASTERN
UPPER. WITH COOLING OCCURRING THROUGHOUT THE ATMOSPHERE NOW...MOST
ALL AREAS HAVE SWITCHED OVER TO SNOW...OR LIGHT SNOW AND DRIZZLY
CONDITIONS UNDERNEATH DEEPER MOISTURE PEELING OFF TO THE EAST.
LATEST SATELLITE AND UPSTREAM SFC OBS SHOWING THAT EVERYONE IS
LIKELY TO GET INTO A PERIOD OR TWO OF DRIZZLE/FREEZING DRIZZLE. THE
WORST OF IT IS OVER NOW...AND WILL CANCEL THE WARNINGS FOR ALL BUT
EASTERN UPPER...WHERE SOME ADDITIONAL ACCUMULATIONS ARE
POSSIBLE...BUT EVEN HERE...DAY CREW MAY DECIDE TO END THE HEADLINES
BY LATE MORNING.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
ISSUED AT 350 AM EDT FRI APR 12 2013
CURRENTLY...POTENT UPPER LEVEL CLOSED LOW IS DRIFTING ACROSS THE
FAR NRN MISSISSIPPI VALLEY...WITH OCCLUDED LOW PRESSURE FROM THE
APPALACHIANS...AND TROUGHING/TROWAL EXTENDING BACK INTO SRN
WISCONSIN. MAIN H8-H7 WARM ADVECTION EXTENDS ALONG H8 WIND SPEED
MAX WHICH IS NOW EXTENDING FROM THE EASTERN GREAT LAKES BACK AROUND
THROUGH EASTERN UPPER MICHIGAN. THIS IS WHERE ONE SWATH OF BETTER
PRECIPITATION...IN THE FORM OF SNOW AND SOME SLEET...IS CO-LOCATED
WITH STRONG POCKET OF UPPER DIVERGENCE IN RIGHT ENTRANCE REGION OF
QUEBEC 120+KT UPPER JET. ANOTHER JET STREAK WAS CROSSING THE OHIO
RIVER VALLEY...AND ANOTHER POCKET OF UPPER DIVERGENCE IN LEFT EXIT
REGION OF WAS DEVELOPING ACROSS THE EASTERN GREAT LAKES. DPVA
AROUND THE CLOSED LOW ALOFT...COMBINED WITH THESE FORCING
MECHANISMS...HAS RESULTED IN MODEST TO STRONG DEEP LAYER LIFT AND
WIDESPREAD PRECIPITATION ACROSS MAINLY NE LOWER AND BACK AROUND
THROUGH EASTERN UPPER.
NOW...THERMALLY SPEAKING...WE HAVE GONE THROUGH QUITE ALONG PERIOD
OF SLEET AND FREEZING RAIN IN NRN LOWER...AS 00Z APX SOUNDING TELLS
THE STORY. 800-700MB DEEP 2-3C WARM NOSE IS EVIDENT...WITH A
COUNTERING DEEP SFC-800MB COLD LAYER WITH A MAXIMUM -6C READING AT
900MB...COLD ENOUGH TO RE-FREEZE TOTALLY MELTED DROPS FROM THAT 2-3C
DEEP WARM NOSE. ONE OF THE BETTER SLEET SOUNDINGS THIS FORECASTER
HAS SEEN. AS THE ENTIRE SYSTEM HAS BEEN SLOW TO TRANSITION NORTH AND
EAST WITH TIME...QUITE A BIT OF SLEET HAS BEEN ABLE TO FALL AND
ACCUMULATE. ACROSS EASTERN UPPER...SOME SLEET MAY BE TRYING TO MIX
WITH WHAT SHOULD BE PRIMARILY SNOW...BASED ON LATEST DUAL POL RADAR
LOOPING. RUC FCST SOUNDINGS ALSO SUGGEST ALL SNOW IN EASTERN
UPPER...WITH THE ELEVATED WARM COOLING STARTING AS OF THIS WRITING.
LATEST OBS SUGGESTING THAT THIS MAY BE TAKING PLACE NOW WITH MORE
OBSERVATIONS ACROSS THE WEST NOW LOOKING MORE "SNOWY" RATHER THAN
"ICY". ALSO IN THE MIX...IS THE CURRENT EFFORT FOR DEEPER MOISTURE
TO STRIP OUT ALOFT FROM THE WEST...WHICH ALLOWS US TO EXPERIENCE YET
ANOTHER PRECIPITATION TYPE...DRIZZLE AND FREEZING DRIZZLE.
IT SHOULD BE WORTH NOTING THAT NOT ALL FOLKS HAVE EXPERIENCED THIS
PLETHORA OF NASTY WINTRY WEATHER. DOWNSLOPING REGIONS ACROSS NW
LOWER...MAINLY FRANKFORT AND MANISTEE AREAS...WERE ABOVE FREEZING
FOR MUCH OF THE NIGHT...SO NOT FREEZING RAIN THERE.
IN THE SPIRIT OF A FORMER NWS COLLEAGUE..."WELL...AT LEAST IT`S
WINDY". YEAH...EAST WINDS WERE GUSTING AS HIGH AS 35-40 MPH MUCH OF
THE NIGHT TOO.
NOW...THE FORECAST...POTENT UPPER LOW WILL LIFT INTO EASTERN LAKE
SUPERIOR TODAY AND TONIGHT...WITH THE SFC TROUGHING/TROWAL AND
AXIS OF DEEPER MOISTURE AND FORCING LIFTING NORTH AND EAST
THROUGH THE MORNING. COLDER AIR SEEPS IN...AND THE TRANSITION OVER
TO MAINLY LIGHT SNOW WILL BE JOINED BY DRIZZLE AND FREEZING
DRIZZLE DUE TO DRYING ALOFT. THE THERMAL PROFILES BECOME AN
INCREASINGLY LIGHT SNOW/DRIZZLE LOOK...AS MOISTURE WILL BE AT OR
BELOW 10C FOR MOST OF THE DAY AND EVEN INTO THE EVENING. THE BEST
MOISTURE/FORCING WILL BE ACROSS CHIPPEWA COUNTY FOR THE LONGEST
PERIOD OF TIME. HERE...ALTHOUGH TOTAL QPF/SNOWFALL WERE LOWERED
SLIGHTLY...WILL STILL SEE A GRAND TOTAL OF 4 TO 8 INCHES BY THE
END OF THE DAY. LESSER AMOUNTS HEADING SOUTH UNTIL JUST AN INCH
DOWN NEAR THE M-55 CORRIDOR. CURRENT WINTER STORM HEADLINES WILL
HOLD TRUE...ENDING FROM SOUTH TO NORTH THROUGH THE DAY. LIGHT
SNOWS AND DRIZZLE ARE LIKELY AT LEAST INTO THE EVENING DUE TO THE
LOW LEVEL CONVERGENCE ASSOCIATED WITH THE ACTUAL SFC TROUGHING.
EVENTUALLY BY LATER TONIGHT...THE LOW LEVEL TROUGHING
WEAKENS/DEPARTS...WITH THE ENTIRE ATMOSPHERIC COLUMN COLD ENOUGH
FOR JUST SNOW. CAN MAKE A REAL GOOD ARGUMENT FOR LIKELY SNOWS FOR
MOST EVERYONE AT SOME POINT DURING THE NIGHT. THIS DUE NOT ONLY TO
THE LINGERING TROUGHING AT THE SFC...BUT ALSO WITH MID LEVEL
TROUGHING WITH THE UPPER CIRCULATIONS...WHICH WILL BE ALIGNED
ACROSS EASTERN UPPER. THUS...WILL HAVE THE BETTER ACCUMULATIONS
AND CHANCES FOR SNOW THERE. MAYBE ANOTHER INCH ACROSS EASTERN
UPPER...WITH LESSER AMOUNTS HEADING FURTHER SOUTH.
CLOUDY THROUGH THE PERIOD WITH LITTLE DIURNAL SWINGS IN
TEMPERATURE. HIGHS IN THE 30S TODAY...WITH LOWS IN THE MIDDLE 20S
TO LOWER 30S.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 350 AM EDT FRI APR 12 2013
SATURDAY...AS THE 500 MB LOW DRIFTS EAST JUST NORTH OF THE FORECAST
AREA, THERE WILL BE ENOUGH FORCING TO CONTINUE THE SNOW SHOWERS.
HOWEVER, THE KICKER IS THAT THE 850 MB TEMPERATURES FALL TO AROUND
-10C AND WITH THE WATER TEMPERATURES SLIGHTLY WARMER AROUND +1 TO
+2C WE WILL PROBABLY GET SOME ENHANCEMENT ESPECIALLY NEARER THE SFC
AND 500 MB LOWS. SO WILL HAVE AN AREA OF LIKELY POPS IN E UPPER AND
ENHANCED CHANCE POPS IN NW LOWER. BY 00Z, THINGS BEGIN TO LOOK LIKE
LAKE EFFECT, HOWEVER, THE PROBLEM IS THAT THE 850 MB TEMPERATURES
BEGIN TO WARM BIT, AND WE LOSE THE ENHANCEMENT.
SATURDAY NIGHT...WE LOSE GOOD 850 MB AND SFC FLOW AS THE
TEMPERATURES RISE TO AROUND -8C. WILL ALLOW FOR SOME FLURRIES EARLY,
BUT ALL THINGS BEING EQUAL, THINK THAT THE WITH THE DRIER AIR MOVING
IN AS WELL, THAT THE SNOW WILL STOP SHORTLY HAVE 00Z.
SUNDAY...THE NEXT SYSTEM BEGINS TO LIFT NORTH INTO NORTHERN PLAINS.
THE GFS HAS IT A LITTLE MORE EAST IN MINNESOTA, WHILE THE 00Z ECMWF
HAS IT IN E NORTH DAKOTA. THE DIFFERENCE IS THAT THE GFS BRINGS
CHANCE POPS INTO NW LOWER SOONER. WITH THESE SYSTEMS BEING KIND OF
ALL OVER THE PLACE, IN THE RUN UP TO THEM, WILL HEDGE BETWEEN THE
TWO. SO CUT THE POPS BACK SO THAT NW LOWER HAVE SOME CHANCE POPS,
AND THE REST OF THE REGION IS RELATIVELY DRY. OVERNIGHT, THE WARM
FRONT IN EITHER CASE MAKES IT FAR ENOUGH NORTH RAIN TAKES OVER IN E
UPPER. THE FRONT STALLS THERE AS WELL SO THAT THE SFC LOW RIDES UP
INTO LAKE SUPERIOR ALONG IT. SO RAIN WILL BE EXPECTED IN E UPPER AND
WITH THE WARM SECTOR MOVING NORTH WILL HAVE LESS CHANCES TO THE
SOUTH.
EXTENDED (MONDAY THROUGH THURSDAY)...MONDAY, EXPECTING RAIN FROM THE
SYSTEM MOVING THROUGH DURING THE DAY. OVERNIGHT, WITH THE FRONT
THROUGH AND THE SFC LOW TO THE EAST, WILL EXPECT THAT E UPPER AND
PORTIONS OF N LOWER WILL CLEAR OUT AS HIGH PRESSURE BUILDS INTO THE
REGION. TUESDAY, THE FRONT HOLDS TO THE EAST WITH HIGH PRESSURE
NOSING INTO LOWER MICHIGAN. LOOKS LIKE SOME RAIN COULD HOLD ON WITH
WAVES RUNNING UP THE FRONT. SO WILL ALLOW FOR SOME RAIN IN NE
LOWER. WEDNESDAY, THE NEXT SYSTEM BEGINS TO PUSH OUT OF THE SOUTHERN
PLAINS AND BY THE TIME THAT IT GETS INTO THE MID-MISSISSIPPI VALLEY,
THE RAIN WILL SPREAD BACK NORTH THROUGH N LOWER AND IN E UPPER,
WHERE A MIX WILL BE EXPECTED. OF COURSE, THE WARM AIR WILL CONTINUE
NORTH CHANGING THE SNOW BACK TO RAIN OVERNIGHT. THURSDAY, THE MODELS
HAVE TWO DIFFERENT TRACKS. THE ECMWF STILL BRINGS THE SFC LOW OVER N
LOWER, WHICH WOULD BRING MORE RAIN TO THE REGION BEFORE CHANGING TO
SNOW THURSDAY NIGHT. THE GFS BRINGS THE SFC LOW UP THROUGH LAKE
ERIE. THIS WOULD BRING SNOW OR RAIN AND SNOW TO N LOWER AND E UPPER.
DECIDED TO PLAY AS RAIN THURSDAY, RAIN/SNOW THURSDAY NIGHT FOR NOW.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 712 AM EDT FRI APR 12 2013
WIDESPREAD MVFR CIGS WILL PREVAIL THROUGHOUT THE TAF PERIOD WITH
LOADS OF LOW LEVEL MOISTURE SURROUNDING LOW PRESSURE LIFTING THROUGH
NRN MICHIGAN TODAY. MOISTURE IS QUICKLY PEELING OUT ALOFT EARLY IN
THE TAF PERIOD WHILE TEMPERATURES ARE COOLING THROUGHOUT THE
ATMOSPHERE. THIS IS RESULTING IN A TRANSITION TO A SCENARIO
CHARACTERIZED AS PERIODS OF LIGHT SNOW AND DRIZZLE/FREEZING DRIZZLE.
THIS WILL BE THE COMMON THEME INTO THE EVENING...BEFORE ONLY LIGHT
SNOW SHOWERS ARE GOING TO BE POSSIBLE FOR THE LATE NIGHT HOURS.
GUSTY EAST WINDS TO 30 MPH AT PLN/APN WILL DIE OFF THROUGH THE
DAY...JUST AS THEY DID ACROSS MBL AND TVC. THESE WINDS WILL
GRADUALLY BACK AROUND OUT OF THE NORTH AND ULTIMATELY THE WEST BY
SATURDAY MORNING...AS THE LOW PRESSURE EXITS FURTHER EAST.
&&
.MARINE...
ISSUED AT 350 AM EDT FRI APR 12 2013
GALE FORCE GUSTS ARE IN FULL EFFECT ACROSS MOST OF THE SURROUNDING
NEARSHORE WATERS OF LAKES HURON AND MICHIGAN...NORTH OF GRAND
TRAVERSE LIGHT AND STURGEON POINT LIGHT. NORTH OF THERE...SOLID
ADVISORY LEVEL GUSTS WERE ONGOING...WHILE SOUTH OF THE
GALES...WINDS WERE DROPPING OFF RATHER QUICKLY WITH A LOOSE
GRADIENT ALONG LOW PRESSURE LIFTING NORTHWARD. THIS LIGHTER
GRADIENT WILL GRADUALLY OVERTAKE ALL OF THE NEARSHORE WATERS
THROUGH THE DAY...WITH GALES GRADUALLY STEPPING DOWN INTO
ADVISORY...THEN SUB ADVISORY LEVELS. THE LOW PRESSURE LIFTS EAST
TONIGHT...WITH COLD ADVECTION AND WESTERLY WINDS DEVELOPING...BUT
EXPECTATIONS ARE FOR WINDS TO BE BELOW ADVISORY LEVELS THROUGH
EARLY SUNDAY. THE NEXT LOW PRESSURE SYSTEM IS SET FOR LATER SUNDAY
AND INTO MONDAY. ADDITIONAL HEADLINES MAY BE REQUIRED.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WARNING UNTIL 7 PM EDT THIS EVENING FOR MIZ008-015.
LH...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LHZ349.
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LHZ345>348.
LM...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LMZ323-341-
344.
GALE WARNING UNTIL 11 AM EDT THIS MORNING FOR LMZ342.
LS...SMALL CRAFT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR LSZ321-322.
&&
$$
UPDATE...SD
SYNOPSIS...JL
SHORT TERM...SD
LONG TERM...JL
AVIATION...SD
MARINE...SD
AREA FORECAST DISCUSSION
NWS RALEIGH NC
740 AM EDT FRI APR 12 2013
.SYNOPSIS...
A STRONG FRONTAL SYSTEM WILL CROSS THE REGION TODAY. WEAK HIGH
PRESSURE WILL BUILD INTO THE REGION FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH SATURDAY/...
AS OF 208 AM THURSDAY...
SYNOPTIC PICTURE: LARGE STACKED MID-UPPER LOW OVER IA WOBBLES NNE
THROUGH THE U.P. OF MI/LAKE SUPERIOR INTO ONTARIO THROUGH SATURDAY.
A SHORTWAVE TROUGH OVER GA/ERN TN OVERNIGHT WILL DAMPEN AS IT TRACKS
TO THE NE THROUGH NC THROUGH MIDDAY TODAY. AT THE SURFACE... AN
OCCLUDING FRONT WILL ROTATE UP THROUGH THE CENTRAL APPALACHIANS
TODAY WITH A TRAILING COLD FRONT SWEEPING EASTWARD THROUGH CENTRAL
NC BETWEEN 12Z-21Z. THIS FRONT WILL DISSIPATE OVER THE COASTAL PLAIN
BY 00Z... THEN A SECONDARY COLD FRONT WILL DROP SE THROUGH THE AREA
TONIGHT. WEAK HIGH PRESSURE CURRENTLY OVER THE HIGH PLAINS WILL
BUILD INTO THE WRN CAROLINAS FROM THE WEST ON SATURDAY.
THROUGH TODAY: SEVERE WEATHER THREAT PERSISTS FOR CENTRAL NC BUT
MANY QUESTIONS REMAIN. PROMINENT WELL-ORGANIZED SQUALL LINE FROM SW
VA THROUGH THE WRN CAROLINAS/ERN GA REMAINS RATHER POTENT... AND IS
WELL-SUPPORTED BY STRONG DYNAMIC FORCING FOR ASCENT INCLUDING MID
LEVEL DPVA AND INTENSE UPPER DIVERGENCE ASSOCIATED WITH A STRONG
SRLY JET STREAK OVER MI/IN/IL. BUT CLOUD TOP TEMPS HAVE BEEN
STEADILY WARMING IN THE LAST FEW HOURS... LIKELY DUE IN PART TO THE
SLOWLY WANING FORCING WITH THE WEAKENING WAVE AND JET STREAK. BOTH
THE INSTABILITY (ALBEIT MARGINAL) AND THE WIND FIELD (0-6 KM SHEAR
OF 40-50 KTS) HOWEVER REMAIN SUFFICIENT FOR MAINTENANCE OF THIS
CONVECTIVE LINE. ANOTHER BAND OF STORMS QUICKLY FORMING FROM AROUND
CAE DOWN TOWARD SAV IS IN A POCKET OF LOWER INSTABILITY WITH WEAK
CAPPING... BUT SHOULD PERSIST AND GROW UPSCALE AS IT ENCOUNTERS
BETTER INSTABILITY (MUCAPE NEAR 1000 J/KG) OVER THE SOUTHERN HALF OF
CENTRAL NC. CONVECTION-ALLOWING MODELS TAKE THIS CONVECTION NNE INTO
SOUTH CENTRAL/ERN NC WHILE BEING SLOWLY OVERTAKEN BY THE PRIMARY
SQUALL LINE. WHILE THE WEAKENING DYNAMICS ARE OF CONCERN... AS ARE
THE LOWERING MID LEVEL LAPSE RATES TO UNDER 6 C/KM... MODELS HOLD
ONTO MARGINAL INSTABILITY OF 500-1000 J/KG SBCAPE FOR THE NEXT 6
HOURS WHILE LOW LEVEL SHEAR REMAINS FORMIDABLE AT 35-40 KTS WITH
STRONGLY CURVING HODOGRAPHS ON RAP BUFR SOUNDINGS (ENHANCED BY
BACKING LOW LEVEL WINDS IN RESPONSE TO THE DEEPENING OCCLUDED
SURFACE LOW OVER WV/WRN VA ALONG WITH THE ARRIVAL OF THE 40-50 KT
SWRLY LOW LEVEL JET) TOWARD DAYBREAK. THIS SHOULD BE ENOUGH TO
SUPPORT A THREAT OF A FEW STRONG TO SEVERE CELLS WITH POSSIBLE
ROTATION... EITHER WITHIN THE MAIN SQUALL LINE OR IN THE PRECEDING
BAND... PRIMARILY FROM 06Z-14Z. DAMAGING WINDS AND ISOLATED
TORNADOES CONTINUE AS THE PRIMARY THREATS HERE. A SHORT LULL IN
STORM STRENGTH/ORGANIZATION IS LIKELY TO FOLLOW THIS MORNING WITH
THE DIMINISHING UPPER DIVERGENCE AND EXITING SHORTWAVE TROUGH. BUT
DEVELOPMENT OF ANOTHER LINE OF SCATTERED SHALLOW CONVECTION IS
EXPECTED BY AFTERNOON ALONG THE WEAKENING LEADING SURFACE FRONT...
ON THE LEADING EDGE OF THE INCOMING MID LEVEL DRY PUNCH. DESPITE
WANING LOW LEVEL MASS CONVERGENCE AND A FALLOFF OF LOW LEVEL SHEAR
AS SURFACE WINDS VEER TO SW AND WSW... THE RAP SHOWS SBCAPE
REBOUNDING TO 1000-1500 J/KG EAST OF HIGHWAY 1 THIS AFTERNOON WITH
LOW-MID LEVEL WINDS BECOMING UNIDIRECTIONAL GENERATING STRAIGHT-LINE
HODOGRAPHS. WILL RETAIN SCATTERED SHOWERS AND STORMS THROUGH THE
AFTERNOON IN THE EASTERN CWA... BECOMING MORE PATCHY AND SHALLOW
WITH CONTINUED DRYING ALOFT BY LATE AFTERNOON. HIGHS 77-84 AS
THICKNESSES HOLD IN THE 1375-1385 METER RANGE. STOUT WINDS FROM THE
SOUTH WILL BECOME MORE SSE THIS MORNING BEFORE SHIFTING TO SW BY
AFTERNOON.
FOR TONIGHT/SATURDAY: EXPECT A FEW LINGERING SHOWERS OVER THE
NORTHEAST SECTIONS THROUGH EARLY EVENING ALONG THE LEADING FRONT...
BUT OTHERWISE THE INCOMING DRIER AIR IN THE LOWEST 2-2.5 KM FAVORS A
WEST-TO-EAST CLEARING TREND DURING THE EVENING AS SURFACE WINDS
DIMINISH AND BECOME WEST THEN NW. WITH FALLING THICKNESSES AS THE
SECONDARY FRONT PASSES BY AND DECENT RADIATIONAL COOLING LIKELY...
HAVE NUDGED DOWN LOWS SLIGHTLY TO THE MID 40S TO LOW 50S. WEAK
SURFACE HIGH PRESSURE RIDGING FROM THE WEST AND LIGHT MAINLY
WESTERLY SURFACE FLOW WILL FOLLOW FOR SATURDAY. WE SHOULD SEE A FEW
HIGH CLOUDS STREAK ACROSS THE WRN/NRN SECTIONS EARLY SATURDAY
MORNING AS A WEAK MID LEVEL PERTURBATION MOVES NE OVER THE SRN
APPALACHIANS AND A 100-120 KT JETLET STREAKS BY TO OUR NNW... BUT
ASIDE FROM THIS WE SHOULD SEE PLENTY OF SUNSHINE WITH A FAIRLY DRY
COLUMN AS PW VALUES DROP TO NEAR OR JUST UNDER NORMAL. HIGHS 70-75.
-GIH
&&
.SHORT TERM /SATURDAY NIGHT THROUGH TUESDAY/...
AS OF 230 AM FRIDAY...
WEAK HIGH PRESSURE MOVING OVER THE NORTHEASTERN US WILL EXTEND
SOUTH ACROSS THE CAROLINAS SUNDAY AS SHORTWAVE RIDGING DEVELOPS OVER
THE MID-ATLANTIC STATES AND GREAT LAKES REGION. LOW LEVEL
THICKNESSES SHOULD START OUT AROUND 1350M SUNDAY MORNING...WHICH IS
RIGHT AT NORMAL VALUES...AND HIGHS WILL ACCORDINGLY BE IN THE LOWER
70S MOST EVERYWHERE. A LOW AMPLITUDE SOUTHERN STREAM SHORTWAVE IS
FORECAST TO UNDERCUT THE RIDGE SUNDAY NIGHT AND TRACK EAST ACROSS
THE SOUTHEASTERN US THROUGH MONDAY. THIS WILL LIKELY LEAD TO A
CHANCE OF SHOWERS...MAINLY ACROSS THE SOUTH ON MONDAY BEFORE A MORE
PRONOUNCED MID/UPPER LEVEL RIDGE DEVELOPS BY TUESDAY. THE GFS NOW
SHOWS THE INVERTED COASTAL TROUGH THAT THE ECMWF HAS BEEN SHOWING IN
RECENT RUNS...DELAYING RETURN FLOW DEVELOPMENT AND KEEPING AN
EASTERLY COMPONENT TO THE LOW LEVEL FLOW WITH WEAKER MIXING BOTH
MONDAY AND TUESDAY. BECAUSE OF THIS...HAVE LOWERED HIGHS A COUPLE
OF DEGREES BOTH DAYS...WITH LOW/MID 70S MONDAY AND UPPER 70S
TUESDAY. LOWS IN THE LOWER 50S SUNDAY NIGHT AND MID 50S MONDAY NIGHT.
&&
.LONG TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 230 AM FRIDAY...
IN THE EXTENDED PERIOD...THE LONGWAVE PATTERN BECOMES QUITE SIMILAR
TO THE PATTERN OBSERVED THIS WEEK...WITH A RELOADING TROUGH OVER THE
WESTERN US AND RIDGING DOWNSTREAM OVER THE EASTERN US. THIS WILL
LEAD TO A RE-ESTABLISHMENT OF SOUTHERN RETURN FLOW AND TEMPS
CONTINUING TO CLIMB ABOVE NORMAL. THE GFS AND ECMWF THEN SHOW SOME
DISAGREEMENT ON HOW QUICKLY THE SYNOPTIC FRONT WILL TRANSLATE EAST
BY MID TO LATE WEEK. THE GFS SHOWS LESS OF A MID-LEVEL CAP AND MORE
INSTABILITY BY WEDNESDAY...PARTICULARLY OVER THE WESTERN CWA...WITH
THE RIDGE BREAKING DOWN MORE RAPIDLY. PREFER THE DRIER ECMWF WHICH
SEEMS TO FIT BETTER WITH PERSISTENCE AND THE REDEVELOPMENT OF THE
CURRENT PATTERN....KEEPING POPS OUT OF THE FORECAST UNTIL
THURSDAY/FRIDAY WHEN HEIGHTS MAY BEGIN TRULY TO FALL AHEAD A
SHORTWAVE LIFTING THROUGH THE MIDWEST STATES.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
AS OF 740 AM FRIDAY...
MVFR CIGS WILL DOMINATE THIS MORNING AS A VIGOROUS FRONTAL SYSTEM
MOVES THROUGH CENTRAL NC. MVFR TO BRIEFLY IFR VSBYS ARE POSSIBLE AS
WELL AT RDU/RWI/FAY THROUGH 15Z ACCOMPANYING RAIN AND STORMS.
SURFACE WINDS HAVE BRIEFLY LOWERED TO 8-12 KTS WITH OCCASIONAL GUSTS
TO 15-18 KTS... HOWEVER SURFACE WINDS SHOULD INCREASE ONCE AGAIN BY
17Z AS WE MIX VERTICALLY AND DRAW DOWN 30-40 KT SW WINDS JUST OFF
THE SURFACE. CIGS SHOULD LIFT TO VFR AT GSO/INT BY 14Z AND RDU BY
15Z... BUT MVFR CIGS ARE LIKELY TO HOLD THROUGH MUCH OF THE DAY...
UNTIL 20Z-22Z... AT RWI/FAY. SKIES ARE EXPECTED TO CLEAR OUT AFTER
00Z AT INT/GSO AND AFTER 03Z AT RDU/RWI/FAY WITH WINDS BECOME
WESTERLY AND DECREASING TO UNDER 10 KTS. VFR CONDITIONS WILL HOLD
OVERNIGHT.
LOOKING BEYOND 12Z SATURDAY MORNING... HIGH CONFIDENCE IN VFR
CONDITIONS THROUGH SUNDAY. MVFR TO IFR CONDITIONS ARE POSSIBLE LATE
SUNDAY NIGHT THROUGH MONDAY NIGHT AS ANOTHER STORM SYSTEM MOVES
THROUGH. GRADUAL RETURN TO VFR CONDITIONS TUESDAY. -GIH
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CBL
NEAR TERM...HARTFIELD
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...HARTFIELD
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
600 AM CDT FRI APR 12 2013
.UPDATE...
ISSUED AT 600 AM CDT FRI APR 12 2013
GETTING REPORTS OF FREEZING DRIZZLE FROM COOPERSTOWN TO VALLEY
CITY. RAP 10Z SOUNDING INDICATES A DRY LAYER FROM 700MB-
500MB...WITH THE SATURATED LAYER BELOW -8C TO -10C. THIS SOUNDING
IS NOT AN IDEAL SUPERCOOLED WATER DROPLET SCENARIO...BUT IT IS
OCCURRING. THE RAP DOES SATURATE THE 700MB-500MB LAYER AFTER
15Z...WHICH SHOULD ALLOW THE P-TYPE TO BE ALL SNOW AGAIN. WILL
INCLUDE FZDZ IN THE AREA UNTIL 15Z...AND ISSUE A SPS (A FEW CARS
REPORTED TO BE IN DITCH ALONG I-94).
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 355 AM CDT FRI APR 12 2013
THE UPPER LEVEL LOW WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH
THE PERIOD. MODELS ARE IN GOOD AGREEMENT AND WILL USE A BLEND FOR
DETAILS. THE MAIN CHALLENGE FOR TODAY WILL BE SNOW CHANCES AND
AMOUNTS. UPPER LEVEL ENERGY CONTINUES TO ROTATE AROUND THE UPPER
LEVEL LOW...AND ANOTHER SHOT OF FORCING/MOISTURE IS HEADED TOWARD
THE EASTERN FA FOR THE MORNING HOURS. GIVEN UPSTREAM
OBSERVATIONS...RADAR IMAGERY...AND MODEL GUIDANCE...EXPECT AN
ADDITIONAL 2-4 INCHES OF SNOW ACROSS THE FAR EASTERN FA. SCATTERED
SNOW SHOWERS AND AN INCH OR TWO OF SNOW WILL OCCUR ALONG AND WEST
OF THE VALLEY. CLOUDS WILL HOLD STRONG TODAY...AND MAX TEMPS
SHOULD BE SIMILAR TO YESTERDAY.
THE UPPER LOW FINALLY MOVES FAR ENOUGH EAST BY SATURDAY THAT
RIDGING SHOULD BE ABLE TO MOVE INTO THE REGION. DID CLEAR SKIES ON
SATURDAY...HOPEFULLY IT ACTUALLY HAPPENS. MIN TEMPS FRIDAY NIGHT
WILL BE INFLUENCED BY CLOUDS...AND MODELS INDICATING THAT CLOUDS
WILL NOT ERODE UNTIL SATURDAY AFTER SUNRISE...SO RAISED VALUES A
FEW DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 355 AM CDT FRI APR 12 2013
SATURDAY NIGHT-SUNDAY NIGHT...THE POSSIBLE SIGNIFICANT WINTER
STORM WILL BE THE MAIN CHALLENGE. 00Z MODELS ARE ALL IN AGREEMENT
THAT THE POTENTIAL EXISTS FOR HEAVY SNOWFALL AND STRONG
WINDS...AND ARE ALL FAIRLY SIMILAR WITH SYNOPTIC FEATURES. CURRENT
WATER VAPOR IMAGERY INDICATES A VERY STRONG WAVE NEAR THE GULF OF
ALASKA. THIS WAVE WILL DIVE SOUTHEAST AND INTO THE REGION BY
SUNDAY OR SUNDAY NIGHT...STALLING ONCE IT REACHES EASTERN NORTH
DAKOTA. MODELS INDICATE A BAND OF WARM AIR ADVECTION/FRONTOGENETICAL
FORCING ACROSS THE SOUTHERN FA BY SUNDAY MORNING...LIFTING
NORTHWARD THROUGH THE DAY ON SUNDAY...WITH WIDESPREAD 0.50 TO 1.00
INCH QPF (PWATS 0.5-0.6 INCHES). SREF P-TYPE PROBABILITY AND
ECMWF THERMAL PROFILES SUGGEST THIS TO BE ALL IN THE FORM OF SNOW.
THE GFS AND GEM DO BRING A WARM LAYER INTO THE FAR SOUTHEAST FA ON
SUNDAY...BUT THIS WOULD ONLY BE FOR A BRIEF PERIOD OF TIME. USING
AROUND A 13:1 RATIO DURING THE NIGHTTIME HOURS...AND 9:1 RATIO
DURING THE DAYTIME HOURS LEADS TO WIDESPREAD 7-14 INCHES OF SNOW
(AND CANNOT RULE OUT HIGHER AMOUNTS WHERE HEAVIER BANDS SET UP).
WINDS WILL ALSO BE AN ISSUE WITH THE GFS AND ECMWF INDICATING
925MB WINDS AROUND 35 KNOTS FROM THE EAST ON SUNDAY...AND THEN
FROM THE NORTH/NORTHEAST SUNDAY NIGHT (CREATING BLOWING SNOW AND
SIGNIFICANTLY REDUCED VISIBILITY). WITH MODELS IN SUCH GOOD
AGREEMENT...AND CONSISTENT FOR THE PAST SEVERAL DAYS...WILL ISSUE
A WINTER STORM WATCH. THE EXACT TRACK OF THE SYSTEM WILL DETERMINE
WHO GETS THE MOST SNOW...AND WHERE THE STRONGEST WINDS OCCUR.
MONDAY-THURSDAY...THE UPPER LOW WILL SLOWLY SHIFT NORTHEAST INTO
ONTARIO ON MONDAY. THE FLOW PATTERN WILL REMAIN BROADLY
CYCLONIC...WITH SOME SNOW SHOWERS/FLURRIES EXPECTED. WITH COLD AIR
ADVECTION AND 925 MB WINDS BETWEEN 30-40 KTS...CONTINUED GUSTY WINDS
ARE EXPECTED...GRADUALLY DIMINISHING DURING THE DAY.
A BREAK IN THE ACTION IS EXPECTED FOR TUESDAY...WITH HIGH PRESSURE
BUILDING INTO THE REGION. A FEW SNOW SHOWERS MAY LINGER...THOUGH.
CONTINUED WEAK COLD AIR ADVECTION WILL LIKELY KEEP MOST AREAS IN THE
30S...15 TO 20 DEGREES BELOW NORMAL.
ANOTHER INTENSE PACIFIC SHORTWAVE TROUGH IS EXPECTED TO DIG SOUTH
TOWARDS THE SOUTHERN ROCKIES BY MID-WEEK...WITH THE UPPER FLOW BECOMING
SOUTHWEST ACROSS THE PLAINS. THE 00Z MODELS LIFT THIS WAVE/SFC CYCLONE
NORTHEASTWARD ALONG THE REMNANT LOW-LEVEL BAROCLINIC ZONE. THE 00Z
GFS REMAINS FARTHER SOUTH COMPARED WITH THE ECMWF. THE ECMWF WOULD
BRING ANOTHER ROUND OF SNOW TO THE AREA...GIVEN IMPRESSIVE MID/UPPER
LEVEL DYNAMICS AND ITS NORTHWARD DISPLACEMENT OF THE UPPER
LOW...DESPITE KEEPING THE SFC LOW WELL TO THE SOUTHEAST. HOWEVER...GFS
ENSEMBLE MEMBERS INDICATE PLENTY OF SPREAD IN THE 500 MB LOW
TRACK...AND OVERALL CONFIDENCE IS LOW AT THIS RANGE. WILL MAINTAIN
CHANCE POPS DURING THE WED-THU PERIOD.
LOW-LEVEL THERMAL FIELDS DO NOT CHANGE MUCH THROUGH THE
PERIOD...WITH 925 MB TEMPS GENERALLY BETWEEN ABOUT -3 AND -8C. AS A
RESULT...HIGH TEMPS SHOULD REMAIN MAINLY IN THE 30S...WITH LOWS IN
THE 20S.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z FRIDAY NIGHT)
ISSUED AT 1151 PM CDT THU APR 11 2013
VFR CONDITIONS WERE GENERALLY OVER NORTHERN MN. MVFR AND SOME IFR
CONDITIONS WERE OVER WESTERN ZONES. EXPECT BANDS OF IFR/MVFR
CONDITIONS TO MOVE THROUGH THE AREA DUE TO SNOW NEXT 24 HOURS AS
UPPER LEVEL SYSTEMS ROTATE AROUND UPPER LEVEL LOW PRESSURE SYSTEM.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR NDZ028>030-038-039-049-052-053.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR NDZ006>008-014>016-024-026-027-054.
MN...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR MNZ002-003-022>024-027>032-040.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR MNZ001-004>009-013>017.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...HOPPES
AREA FORECAST DISCUSSION
NWS MIAMI FL
143 PM EDT FRI APR 12 2013
.AVIATION...
SCATTERED SHOWERS HAVE DEVELOPED OVER THE INTERIOR AND LIFTING TO
THE NNE IN THE MOIST SOUTHERLY FLOW. THE RAPID REFRESH WHICH
PERFORMS VERY WELL HAS BEEN INSISTING IN THE DEVELOPMENT OF LATE
AFTERNOON TSRA OVER EASTERN PALM BEACH AND BROWARD COUNTIES SO PUT
BRIEF MVFR TEMPO GROUPS FOR THOSE TERMINALS. OTHERWISE, MOSTLY VFR
CONDITIONS SHOULD PERSIST. GUIDANCE IS INDICATING SOME LOWER
CLOUDS LATE TONIGHT BUT MAINTAINED VFR FOR NOW. SURFACE WIND WILL
REMAIN SSE ALONG THE EAST COAST THROUGH THE FORECAST OCCASIONALLY
GUSTING TO 20+ KNOTS THIS AFTERNOON ALONG WITH A GULF COAST SEA
BREEZE.
KOB
&&
.PREV DISCUSSION... /ISSUED 1008 AM EDT FRI APR 12 2013/
UPDATE...
THE MORNING SURFACE ANALYSIS SHOWED A COLD FRONT EXTENDING SOUTH
AND SOUTHWEST ACROSS THE FLORIDA BIG BEND TO THE CENTRAL GULF OF
MEXICO WITH MOIST SOUTHERLY FLOW ACROSS THE FLORIDA PENINSULA
AHEAD OF IT. LOCAL OBSERVATIONS SHOWED DEWPOINTS RANGING FROM 70
TO 75 DEGREES. THE MORNING SOUNDING HERE IN MIAMI WAS VERY MOIST
UP TO AROUND 650 MB (PWAT AT 2.03") WITH LIGHT TO MODERATE
SOUTHERLY FLOW THROUGH THE LOW/MID LAYERS. THE LATEST RADAR LOOP
SHOWED MAINLY ISOLATED/SCT SHOWERS SPREADING NORTH ALONG THE EAST
COAST OF BROWARD AND MIAMI-DADE COUNTIES. LATER IN THE
AFTERNOON/EVENING...THE PREVIOUSLY MENTIONED COLD FRONT WILL
CONTINUE TO ADVANCE EASTWARD TOWARD AND INTO CENTRAL FLORIDA. THIS
COMBINED WITH DAYTIME HEATING...PLENTY OF DEEP LAYER MOISTURE AND
THE AFTERNOON SEA BREEZES WILL BE ENOUGH TO SUPPORT SCATTERED
THUNDERSTORMS TODAY. THE BEST CHANCE FOR THESE STORMS WILL REMAIN
OVER THE NORTHERN AND EASTERN SECTIONS OF THE AREA...ESPECIALLY
OVER PALM BEACH COUNTY. THE LATEST HRRR AND WRF ARW MODEL
REFLECTIVITIES LINE UP WELL WITH THIS PATTERN AND INDICATE THE
AFTERNOON CONVECTION INITIATING AND CONCENTRATING OVER THE EAST
COAST FROM BROWARD TO PALM BEACH COUNTIES AFTER 16Z...THEN
TRENDING DOWN THROUGH MID-EVENING PERIOD. THE MAIN IMPACTS FROM
THESE STORMS WILL BE THE POTENTIAL FOR WET MICROBURSTS AND HEAVY
RAINFALL. THE EXPERIMENTAL WMSI INDEX FROM THE LOCALLY RUN WRFNMM
SB-CAPE AND SFC/MID-LEVEL THETA-E INDICATE WIND GUSTS FROM ANY
MICROBURST COULD REACH THE 35 TO 49 KT RANGE FROM ANY STRONG STORM
THAT DOES DEVELOP. FOR THE MORNING UPDATE...WE HAVE SLIGHTLY
INCREASED THE RAINFALL CHANCES TODAY OVER THESE EAST COAST
LOCATIONS MENTIONED. 85/AG
PREV DISCUSSION... /ISSUED 735 AM EDT FRI APR 12 2013/
AVIATION...
LATEST RADAR TRENDS SHOW AREAS OF DIMINISHING RAIN SHOWERS
PUSHING NORTH ACROSS INTERIOR AREAS EARLY THIS MORNING AS A MOIST
LOW LEVEL FLOW SURGES ACROSS THE AREA FROM THE GULF OF MEXICO.
SHOWERS SHOULD CONTINUE TO PUSH TO THE NORTH AND REDEVELOP THROUGH
THE EARLY MORNING HOURS ACCOMPANIED WITH GENERALLY MVFR CIGS FOR
ALL TAF SITES. CANNOT NOT RULE OUT AN ISOLATED IFR CIG FOR A BRIEF
PERIOD SOMETIME THIS MORNING ALONG WITH AN ISOLD TSRA BUT WILL
LEAVE OUT OF THE FORECAST AT THIS TIME. WINDS WILL MOSTLY REMAIN
SSE AND INCREASE THROUGH THE AFTERNOON AS A COLD FRONT APPROACHES
FROM THE NORTH. GULF SEA BREEZE WILL DEVELOP BY LATE THIS MORNING
SO THE THREAT FOR ADDITIONAL CONVECTION WILL REMAIN EAST OF THE
KAPF TERMINAL.
KOB/CD
PREV DISCUSSION... /ISSUED 540 AM EDT FRI APR 12 2013/
DISCUSSION...
CONDITION ARE BEGINNING TO CHANGE THIS MORNING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS IS THE FRONT WE HAVE BEEN EXPECTING
MOST OF THE WEEK. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
FRONT STALLING SOMEWHERE OVER CENTRAL FLORIDA. THIS IS DUE TO
STRONG HIGH PRESSURE TO THE EAST AND THE FACT THAT THE MAIN WILL
BE VERY QUICKLY MOVING TO THE NORTHEAST, TAKING MOST OF THE ENERGY
WITH IT. THERE IS AN AREA OF HIGH PRESSURE MOVING IN BEHIND THE
FRONT. THIS HIGH PRESSURE WILL MERGE WITH THE HIGH PRESSURE SYSTEM
TO THE EAST. AS IT DOES, IT WILL ALLOW FOR A PERIOD OF MOSTLY
QUIET WEATHER FOR NEXT WEEK. THERE WILL STILL BE A SMALL POTENTIAL
FOR AN AFTERNOON SHOWER OR AN ISOLATED THUNDERSTORM TO DEVELOP,
BUT THAT WILL BE MAINLY IN THE AFTERNOON, AND LOOKS TO DIMINISH
TOWARDS THE MIDDLE OF THE WEEK AT THIS TIME.
AS FOR THE DYNAMICS FOR TODAY AND TOMORROW. WELL, THERE IS TYPICAL
INSTABILITY IN PLACE FOR TODAY, AS WELL AS PLENTY OF MOISTURE.
MODELS ARE INDICATING SOME ISOLATED TO SCATTERED SHOWERS AND
POSSIBLY A THUNDERSTORM THIS AFTERNOON. THE HRRR PLACES MOST OF
THE ACTIVITY ALONG THE EAST COAST OF SOUTH FLORIDA. GIVEN THE
SOUTHWESTERLY FLOW, CAN NOT ARGUE AGAINST IT. SO, WHILE POPS ARE
ALL OVER THE CWA, THERE ARE SOME HIGH POPS IN THE NORTHEASTERN
PORTION OF SOUTH FLORIDA.
FOR TOMORROW, THE LONG ANTICIPATED COLD FRONT WILL MOVE INTO THE
FLORIDA PENINSULA. IT CURRENTLY LOOKS TO MAKE IT DOWN JUST ABOUT TO
LAKE OKEECHOBEE BEFORE STALLING. THIS WILL KEEP SOUTH FLORIDA IN
THE WARM SECTOR TOMORROW. THERE WILL ALSO BE A 100KT JET EXITING
CENTRAL FLORIDA, WITH THE TAIL END NEAR MELBOURNE AROUND 00Z
SUNDAY. THIS PLACES THE AREA NEAR LAKE OKEECHOBEE IN THE RIGHT
ENTRANCE REGION OF THE JET. THIS, COMBINED WITH THE SFC BOUNDARY
AND PLENTY OF CAPE, AROUND 1500 JOULES, WILL PROBABLY ALLOW SOME
THUNDERSTORMS TO DEVELOP. SOME OF THOSE STORMS MAY BE STRONG.
THESE WILL MOVE OFF TO THE EAST, ALONG WITH THE UPPER LEVEL
DYNAMICS BY SATURDAY EVENING. THE FRONT WILL DISSIPATE THROUGH THE
DAY ON SUNDAY.
MARINE...
HIGH PRESSURE HAS SHIFTED SLIGHTLY AHEAD OF A COLD FRONT. THIS
WILL CAUSE THE WINDS TO TURN TO THE SW OVER THE GULF TODAY. THE
WINDS OVER THE ATLANTIC WILL TURN MORE SOUTHERLY. THE COLD FRONT
WILL MOVE CLOSER TO SOUTH FLORIDA TONIGHT AND STALL ACROSS SOUTH
CENTRAL FLORIDA BY TOMORROW MORNING. THIS WILL ALLOW SHOWERS AND
THUNDERSTORMS TO DEVELOP THROUGH TOMORROW EVENING. THE FRONT WILL
DISSIPATE THROUGH THE DAY ON SUNDAY, ALLOWING FOR QUIETER WEATHER.
FIRE WEATHER...
THE MAIN CONCERNS WILL BE WIND AND THUNDERSTORMS TODAY AND
TOMORROW. THE WIND WILL TURN FROM THE SOUTHEAST TO BE OUT OF THE
SOUTHWEST TODAY AS HIGH PRESSURE TO THE EAST HAS SHIFTED SOMEWHAT
IN ADVANCE OF A COLD FRONT. THE WINDS ARE EXPECTED TO PICK UP TO
NEAR 15 MPH THIS AFTERNOON. THERE IS A CHANCE OF A THUNDERSTORM
TODAY, MAINLY NORTH OF I75.
BY TOMORROW, THE COLD FRONT WILL STALL OVER SOUTH CENTRAL FLORIDA.
THIS WILL ALLOW THUNDERSTORM DEVELOP ACROSS THE AREA, BUT MAINLY
IN THE LAKE REGION. SOME OF THE STORMS COULD BECOME STRONG. THE
FRONT WILL DISSIPATE THROUGH SUNDAY. QUIETER WEATHER CONDITIONS ARE
EXPECTED NEXT WEEK UNDER HIGH PRESSURE.
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
735 AM EDT FRI APR 12 2013
.AVIATION...
LATEST RADAR TRENDS SHOW AREAS OF DIMINISHING RAIN SHOWERS
PUSHING NORTH ACROSS INTERIOR AREAS EARLY THIS MORNING AS A MOIST
LOW LEVEL FLOW SURGES ACROSS THE AREA FROM THE GULF OF MEXICO.
SHOWERS SHOULD CONTINUE TO PUSH TO THE NORTH AND REDEVELOP THROUGH
THE EARLY MORNING HOURS ACCOMPANIED WITH GENERALLY MVFR CIGS FOR
ALL TAF SITES. CANNOT NOT RULE OUT AN ISOLATED IFR CIG FOR A BRIEF
PERIOD SOMETIME THIS MORNING ALONG WITH AN ISOLD TSRA BUT WILL
LEAVE OUT OF THE FORECAST AT THIS TIME. WINDS WILL MOSTLY REMAIN
SSE AND INCREASE THROUGH THE AFTERNOON AS A COLD FRONT APPROACHES
FROM THE NORTH. GULF SEA BREEZE WILL DEVELOP BY LATE THIS MORNING
SO THE THREAT FOR ADDITIONAL CONVECTION WILL REMAIN EAST OF THE
KAPF TERMINAL.
KOB/CD
&&
.PREV DISCUSSION... /ISSUED 540 AM EDT FRI APR 12 2013/
DISCUSSION...
CONDITION ARE BEGINNING TO CHANGE THIS MORNING IN ADVANCE OF AN
APPROACHING COLD FRONT. THIS IS THE FRONT WE HAVE BEEN EXPECTING
MOST OF THE WEEK. MODELS ARE IN PRETTY GOOD AGREEMENT WITH THE
FRONT STALLING SOMEWHERE OVER CENTRAL FLORIDA. THIS IS DUE TO
STRONG HIGH PRESSURE TO THE EAST AND THE FACT THAT THE MAIN WILL
BE VERY QUICKLY MOVING TO THE NORTHEAST, TAKING MOST OF THE ENERGY
WITH IT. THERE IS AN AREA OF HIGH PRESSURE MOVING IN BEHIND THE
FRONT. THIS HIGH PRESSURE WILL MERGE WITH THE HIGH PRESSURE SYSTEM
TO THE EAST. AS IT DOES, IT WILL ALLOW FOR A PERIOD OF MOSTLY
QUIET WEATHER FOR NEXT WEEK. THERE WILL STILL BE A SMALL POTENTIAL
FOR AN AFTERNOON SHOWER OR AN ISOLATED THUNDERSTORM TO DEVELOP,
BUT THAT WILL BE MAINLY IN THE AFTERNOON, AND LOOKS TO DIMINISH
TOWARDS THE MIDDLE OF THE WEEK AT THIS TIME.
AS FOR THE DYNAMICS FOR TODAY AND TOMORROW. WELL, THERE IS TYPICAL
INSTABILITY IN PLACE FOR TODAY, AS WELL AS PLENTY OF MOISTURE.
MODELS ARE INDICATING SOME ISOLATED TO SCATTERED SHOWERS AND
POSSIBLY A THUNDERSTORM THIS AFTERNOON. THE HRRR PLACES MOST OF
THE ACTIVITY ALONG THE EAST COAST OF SOUTH FLORIDA. GIVEN THE
SOUTHWESTERLY FLOW, CAN NOT ARGUE AGAINST IT. SO, WHILE POPS ARE
ALL OVER THE CWA, THERE ARE SOME HIGH POPS IN THE NORTHEASTERN
PORTION OF SOUTH FLORIDA.
FOR TOMORROW, THE LONG ANTICIPATED COLD FRONT WILL MOVE INTO THE
FLORIDA PENINSULA. IT CURRENTLY LOOKS TO MAKE IT DOWN JUST ABOUT TO
LAKE OKEECHOBEE BEFORE STALLING. THIS WILL KEEP SOUTH FLORIDA IN
THE WARM SECTOR TOMORROW. THERE WILL ALSO BE A 100KT JET EXITING
CENTRAL FLORIDA, WITH THE TAIL END NEAR MELBOURNE AROUND 00Z
SUNDAY. THIS PLACES THE AREA NEAR LAKE OKEECHOBEE IN THE RIGHT
ENTRANCE REGION OF THE JET. THIS, COMBINED WITH THE SFC BOUNDARY
AND PLENTY OF CAPE, AROUND 1500 JOULES, WILL PROBABLY ALLOW SOME
THUNDERSTORMS TO DEVELOP. SOME OF THOSE STORMS MAY BE STRONG.
THESE WILL MOVE OFF TO THE EAST, ALONG WITH THE UPPER LEVEL
DYNAMICS BY SATURDAY EVENING. THE FRONT WILL DISSIPATE THROUGH THE
DAY ON SUNDAY.
MARINE...
HIGH PRESSURE HAS SHIFTED SLIGHTLY AHEAD OF A COLD FRONT. THIS
WILL CAUSE THE WINDS TO TURN TO THE SW OVER THE GULF TODAY. THE
WINDS OVER THE ATLANTIC WILL TURN MORE SOUTHERLY. THE COLD FRONT
WILL MOVE CLOSER TO SOUTH FLORIDA TONIGHT AND STALL ACROSS SOUTH
CENTRAL FLORIDA BY TOMORROW MORNING. THIS WILL ALLOW SHOWERS AND
THUNDERSTORMS TO DEVELOP THROUGH TOMORROW EVENING. THE FRONT WILL
DISSIPATE THROUGH THE DAY ON SUNDAY, ALLOWING FOR QUIETER WEATHER.
FIRE WEATHER...
THE MAIN CONCERNS WILL BE WIND AND THUNDERSTORMS TODAY AND
TOMORROW. THE WIND WILL TURN FROM THE SOUTHEAST TO BE OUT OF THE
SOUTHWEST TODAY AS HIGH PRESSURE TO THE EAST HAS SHIFTED SOMEWHAT
IN ADVANCE OF A COLD FRONT. THE WINDS ARE EXPECTED TO PICK UP TO
NEAR 15 MPH THIS AFTERNOON. THERE IS A CHANCE OF A THUNDERSTORM
TODAY, MAINLY NORTH OF I75.
BY TOMORROW, THE COLD FRONT WILL STALL OVER SOUTH CENTRAL FLORIDA.
THIS WILL ALLOW THUNDERSTORM DEVELOP ACROSS THE AREA, BUT MAINLY
IN THE LAKE REGION. SOME OF THE STORMS COULD BECOME STRONG. THE
FRONT WILL DISSIPATE THROUGH SUNDAY. QUIETER WEATHER CONDITIONS ARE
EXPECTED NEXT WEEK UNDER HIGH PRESSURE.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 85 73 84 72 / 40 20 50 20
FORT LAUDERDALE 84 74 84 74 / 40 20 50 20
MIAMI 85 74 84 74 / 30 20 40 20
NAPLES 82 70 82 69 / 30 20 50 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS COLUMBIA SC
746 AM EDT FRI APR 12 2013
.SYNOPSIS...
A COLD FRONT WILL APPROACH THE REGION TOWARD MORNING. THE FRONT
WILL MOVE THROUGH THE AREA BY MIDDAY. HIGH PRESSURE WILL BUILD IN
BEHIND THE FRONT FOR THE WEEKEND. THERE WILL BE ANOTHER CHANCE FOR
RAIN EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
COLD FRONT MOVING EXTENDING FROM THE UPSTATE OF SC TO CENTRAL GA
AT 11Z. NARROW BAND OF SHOWERS AHEAD OF FRONT. HIGH RESOLUTION
MODELS AND RAP SUGGEST LOW POPS THROUGH THE MORNING AS DEEPER
MOISTURE IS SHIFTING EAST AND NORTH OF THE REGION ALONG WITH
STRONGER LIFT.
FRONT APPEARS SLOW TO MOVE THROUGH THE REGION SO PREFER WARMER
GUIDANCE WITH TEMPS MAXING OUT IN THE UPPER 70S TO LOWER 80S.
DECREASING CLOUDS BY MIDDAY...BECOMING MOSTLY SUNNY AND BREEZY FOR
A PERIOD THIS AFTERNOON.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
COLD AIR ADVECTION AND CLEAR SKIES BEHIND THE SYSTEM TONIGHT INTO
SATURDAY MORNING WILL LEAD TO NEAR NORMAL LOWS...IN THE UPPER 40S
TO LOWER 50S. FRONT WILL BE WELL OFF THE COAST BY SATURDAY MORNING
WITH HIGH PRESSURE BUILDING IN FROM THE WEST. COOLER AND DRIER
WEATHER ON SATURDAY WITH SEASONABLE TEMPERATURES IN THE MID TO
UPPER 70S.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
NO SIGNIFICANT CHANGES MADE TO THE ONGOING FORECAST FOR THIS TIME
PERIOD. HIGH PRESSURE CENTERED NORTH OF THE FORECAST AREA WILL
DOMINATE SATURDAY NIGHT INTO SUNDAY. LOW PRESSURE OVER THE GULF WILL
MOVE NORTHEAST TOWARD THE REGION LATE SUNDAY INTO MONDAY INCREASING
MOISTURE AND CLOUD COVER. KEPT CHANCE OF POPS FOR MONDAY. SYSTEM
WILL SHIFT OFF THE COAST BY LATE MONDAY WITH AN UPPER RIDGE BUILDING
INTO THE AREA THROUGH WEDNESDAY. ECMWF AND GFS DISAGREE ON TIMING
AND MAGNITUDE OF SYSTEM TOWARD THE END OF THE WEEK. GFS HAS LOW
PRESSURE SYSTEM AND ASSOCIATED STRONG COLD FRONT MOVING THROUGH
THE AREA ON THURSDAY. ECMWF SHOWS A MUCH WEAKER SYSTEM THAT IS
SLOWER TO REACH THE AREA.
&&
.AVIATION /12Z FRIDAY THROUGH TUESDAY/...
HIGH CONFIDENCE FOR MVFR THROUGH 16Z AS A COLD FRONT MOVES ACROSS
THE TAF SITES. A LINE OF SHOWERS ASSOCIATED WITH THE COLD FRONT IS
EXPECTED TO MOVE EAST OF THE TAF SITES BY 16Z.
CEILINGS WILL IMPROVE TO VFR BY MIDDAY REMAIN VFR THROUGH THE END OF
THE TAF PERIOD. LATEST GFS LAMP SHOWING A SIMILAR TREND. STRONG
PRESSURE GRADIENT WILL GIVE WAY TO WESTERLY WINDS 10-15 KTS GUSTING
TO 20-25 KTS THIS AFTERNOON. SKIES WILL CLEAR AS HIGH PRESSURE
BUILDS IN FROM THE WEST. WINDS WILL DECREASE DURING THE EVENING
HOURS AND REMAIN WEST LESS THANT 10 KTS OVERNIGHT WITH CLEAR SKIES.
EXTENDED AVIATION OUTLOOK...PERIODS OF MVFR CIGS WITH SCATTERED
CONVECTION POSSIBLE SUNDAY NIGHT AND INTO MONDAY.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
GA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1158 AM EDT FRI APR 12 2013
.UPDATE...
ISSUED AT 1157 AM EDT FRI APR 12 2013
BEHIND THE DEPARTING LOW PRESSURE SYSTEM...AN UPPER LEVEL DISTURBANCE
WILL ROTATE THROUGH THE OH VALLEY TODAY AND THIS COMBINED WITH SOME
LOW LEVEL MOISTURE FROM RECENT PRECIPITATION SHOULD RESULT IN SOME
CU THIS AFTERNOON. THE CU SHOULD BE MOST WIDESPREAD ACROSS THE NORTH
AND NOT AS MUCH COVERAGE CLOSER TO THE VA BORDER.
TEMPS AND DEWPOINTS WERE FRESHENED UP BASED ON RECENT OBSERVATIONS
AND WINDS WERE INCREASED A BIT...ESPECIALLY ACROSS THE SOUTH. WITH
THE UPDATED ZFP...MORNING WORDING WAS CLEANED UP.
UPDATE ISSUED AT 655 AM EDT FRI APR 12 2013
COLD FRONT IS JUST ABOUT TO PUSH EAST OF PIKE COUNTY WITH ALL OF THE
AREA NOW SEEING TEMPERATURES FALL FAIRLY QUICKLY ALONG WITH
DEWPOINTS. SOME MID 40 TEMPERATURES ALREADY SHOWING UP ACROSS MUCH OF
CENTRAL KENTUCKY. SOME DRIZZLE HAS PERSISTED BEHIND THE DEPARTING
FRONT WITH JUST ENOUGH LOW LEVEL MOISTURE TRAPPED BELOW THE LOW LEVEL
INVERSION. THIS DRIZZLE SHOULD BE SHORT LIVED THIS MORNING AS
CEILINGS INCREASE BY MID MORNING. RUC NOW SHOWS CLOUDS HANGING ON FOR
MOST OF THE DAY...WHILE THE NAM CONTINUES TO SHOW LOW CLOUDS
DISSOLVING. GIVEN LATEST SATELLITE TRENDS...OUR WESTERN COUNTIES MAY
BE CLEARING OUT SHORTLY. GIVEN THE WIND FLOW IS NOT FAVORABLE FOR LOW
CLOUDS HANGING IN TODAY...HAVE OPTED TO GO WITH A BIT FASTER CLEARING
HAVING SKIES GO MOSTLY SUNNY BY THIS AFTERNOON. LOW CLOUDS CAN
SOMETIMES BE TRICKY AND NAM DOES SHOW MORE CLOUDS MOVING IN LATER THIS
AFTERNOON. HOWEVER...AS OF RIGHT NOW...NOT MUCH UPSTREAM...SO OPTING
TO GO A LITTLE MORE OPTIMISTIC.
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 308 AM EDT FRI APR 12 2013
COLD FRONT HAS REACHED THE I-75 CORRIDOR IN THE LAST HOUR AND WILL
CONTINUE TO PUSH EAST ACROSS THE AREA EARLY THIS MORNING...CLEARING
FAR EASTERN KENTUCKY AROUND DAYBREAK. COOLER AND DRIER AIR WILL
FILTER INTO THE AREA TODAY. WITH COLD ADVECTION DURING THE MORNING
HOURS...A SMALL CLIMB FROM MORNING LOWS IS ANTICIPATED. CLOUDS WILL
LIKELY HOLD ON LONGER THAN THE NAM SUGGEST...AND CLOSER TO THE RUC
SOLUTION. THIS HAS CLOUDS EVENTUALLY BREAKING UP BY EARLY AFTERNOON.
THIS WILL ALSO IMPACT THE TEMPERATURE CLIMB TODAY. WE SHOULD BE ABLE
TO AT LEAST REACH THE MID/UPPER 50S...WITH AREAS IN THE SOUTHWEST
POSSIBLY EXCEEDING 60 WITH MORE CLEARING.
HIGH PRESSURE WILL BUILD ACROSS THE AREA TONIGHT INTO TOMORROW WITH
SKIES GOING MOSTLY CLEAR. SHELTERED VALLEYS MAY DECOUPLE TONIGHT
LEADING TO READINGS AT LEAST INTO THE MID 30S. THIS SHOULD ALLOW FOR
SOME LIMITED FROST POTENTIAL TONIGHT. A QUIET SATURDAY IS ON TAP WITH
PLENTY OF SUNSHINE BOOSTING TEMPERATURES INTO THE 60S.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 308 AM EDT FRI APR 12 2013
THE MODELS HAVE COME INTO BETTER AGREEMENT ALOFT THROUGH THE BREADTH
OF THE EXTENDED PORTION OF THE FORECAST. THEY ALL STILL TAKE THE
GREAT LAKES TROUGH EAST EARLY IN THE PERIOD ALLOWING FOR RISING
HEIGHTS OVER KENTUCKY THIS WEEKEND AND INTO THE FIRST PART OF NEXT
WEEK. THEY ALSO ALL HAVE VARIOUS REPRESENTATIONS OF A MINOR TROUGH
PASSING THROUGH THE SOUTHEAST PORTION OF THE NATION DURING THE LATTER
PART OF THE WEEKEND. THIS UNCONSOLIDATED WAVE MAY YET HAVE A
SENSIBLE IMPACT ON THE WEATHER OF EAST KENTUCKY INTO MONDAY MORNING
WITH THE NAM12 THE MOST BEARISH AND THE GFS/GEM RATHER BENIGN.
MEANWHILE...A MODERATELY STRONG CLOSED LOW WILL BE LIFTING NORTHEAST
THROUGH THE NORTHERN PLAINS WELL AWAY FROM OUR AREA. TO THE WEST OF
THIS...A DEEPENING NODE OF THE BROAD NORTHWESTERN TROUGH WILL DEVELOP
INTO A POTENT TROUGH IN ITS OWN RIGHT AND SLOWLY START TO COME EAST.
AS THIS FEATURE STRENGTHENS AND DROPS TOWARD THE FOUR CORNERS REGION
IT WILL HELP TO PUMP UP THE DOWNSTREAM RIDGE OVER THE SOUTHEAST
PORTION OF THE NATION INTO MIDWEEK. THE ECMWF AND GFS ARE IN REAL
GOOD AGREEMENT NOW WITH THE LATTER PORTION OF THE EXTENDED WHILE THE
GEM IS QUICKER AND FURTHER NORTH WITH ITS TROUGH. THIS TROUGH MOVES
INTO THE CENTRAL PLAINS ON THURSDAY WITH HEIGHT FALLS INBOUND FOR
KENTUCKY. GIVEN THE AGREEMENT OF THE PREFERRED MODELS WITH THIS WILL
FAVOR A BLENDED SOLUTION THROUGH THE EXTENDED.
SENSIBLE WEATHER WILL FEATURE A DRY AND COOL START TO THE WEEKEND
WITH PATCHY FROST POSSIBLE IN THE DEEPER VALLEYS OF EAST KENTUCKY
SUNDAY MORNING. HOWEVER...MODERATING HIGH PRESSURE MOVING OFF TO THE
EAST AND A RIDGE BUILDING ALOFT WILL ALLOW FOR A SOLID WARM UP TO
COMMENCE AND CONTINUE INTO MID WEEK. A WEAK SFC WAVE PASSING TO THE
SOUTH OF EAST KENTUCKY LATE SUNDAY NIGHT AND EARLY MONDAY MAY
TRIGGER SOME CONVECTION OVER SOUTHERN PARTS OF THE CWA. ONCE THIS
PASSES...EAST KENTUCKY WILL BE ON THE NORTHWEST FRINGE OF A LARGE
AREA OF HIGH PRESSURE ALLOWING FOR RETURN FLOW MOISTURE TO INVADE
FROM A RELATIVELY OPEN GULF OF MEXICO. THIS MOISTURE WILL SLOWLY
BUILD THROUGH THE WEEK IN THIS EARLY SUMMER-LIKE PATTERN AND RESULT
IN A DAILY CHANCE FOR MAINLY AFTERNOON AND EVENING SHOWERS OR
THUNDERSTORMS THROUGH WEDNESDAY. A BETTER CHANCE OF RAIN CAN BE
ANTICIPATED ON THURSDAY AS A DEEP AREA OF LOW PRESSURE LIFTS OUT OF
THE CENTRAL PLAINS AND MOVES TO THE NORTHERN GREAT LAKES. THIS WILL
DRAG A COLD FRONT INTO KENTUCKY HELPING TO FOCUS THE BUILT UP
MOISTURE. WITH THE BETTER CHANCES OF RAIN THURSDAY WILL LIKELY BREAK
THE TREND OF CLIMBING HIGHS FROM DAY TO DAY.
THE CR GRID LOAD CAME IN PRETTY DECENT...BUT DID NUDGE DOWN POPS ON
MONDAY GIVEN THE UNCERTAINTY AND ALSO FINE TUNED THEM LATER IN THE
EXTENDED MORE TOWARD THE 12Z ECMWF. ALSO MAKE SOME SIGNIFICANT
TERRAIN BASED ADJUSTMENTS FOR LOWS EACH NIGHT...ANTICIPATING DECENT
RIDGE TO VALLEY SPLITS THROUGHOUT THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 655 AM EDT FRI APR 12 2013
CEILINGS WILL IMPROVE THROUGH THE MORNING AS DRIER AIR SPREADS ACROSS
THE AREA IN THE WAKE OF A COLD FRONT. STILL SOME UNCERTAINTY
REGARDING CLOUD COVER LATER THIS AFTERNOON AND EVENING...BUT AS OF
RIGHT NOW...NOT MUCH UPSTREAM TO HANG ANY CONFIDENCE ON THIS CLOUD
COVER. WILL GO MORE OPTIMISTIC WITH THE FORECAST FOR NOW. ANY CLOUDS
THIS AFTERNOON SHOULD REMAIN REMAIN AT OR ABOVE 5KFT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1013 AM EDT FRI APR 12 2013
.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY WITH SHOWERS...FOLLOWED
BY MUCH COOLER TEMPERATURES FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
WITH 1015AM UPDATE...PRIMARY CHANGES HAVE BEEN TO POPS. SHOWERS
ARE MOVING OUT VERY QUICKLY...AND UPDATED TRENDS TO END RAIN
FASTER THAN THE PREVIOUS FORECAST. USED LATEST RUNS OF THE HRRR
AND RUC TO UPDATE HOURLY TEMPERATURES AS WELL. WIND SHIFT IS
EXPECTED AS COLD FRONT COMPLETES ITS PASSAGE ACROSS THE REGION.
TEMPERATURES WILL BE MAINLY STEADY THIS MORNING AND MAY FALL A BIT
BEHIND FROPA THIS AFTERNOON BUT MAIN COLD ADVECTION AT 850MB IS
WELL BEHIND FRONT SO ONLY A BIT OF RECOVERY LATE DAY WHEN A FEW
BREAKS IN CLOUDS MAY HELP MAX TEMPS.
STILL A FEW SHOWERS IN COLD ADVECTION AND NORTHWEST FLOW TONIGHT
MAINLY WELL NORTH AND IN RIDGES.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY/...
MAIN UPPER TROUGH AND SECONDARY PUSH OF COLDER AIR ALOFT WILL
BRING COOLER TEMPERATURES AND A CHANCE FOR SHOWERS SATURDAY MAINLY
FOR LAKE AND TERRAIN ENHANCED AREAS. SURFACE RIDGE WILL BUILD
ACROSS REGION SATURDAY EVENING TO BRING RELATIVELY DRY CONDITIONS.
AS LOW PRESSURE OVER ONTARIO MOVES OFF TO THE NORTHEAST...CANNOT
RULE OUT A STRAY SHOWER OR SNOWFLAKE NORTH OF INTERSTATE 80 SATURDAY
NIGHT. WITH CLEARING SKIES AS HIGH PRESSURE MOVES IN...EXPECT THAT
MOST LOCATIONS WILL DROP TO AROUND THE FREEZING MARK SUNDAY
MORNING. HIGH PRESSURE WILL MOVE OFF THE EAST COAST SUNDAY...BUT
TEMPERATURES SHOULD MOVE BACK TOWARDS CLIMATOLOGY...RISING INTO
THE 50S WITH LOWER 60S EASTERN OHIO.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AT THIS POINT...IT APPEARS THAT NEXT WEEKS WEATHER WILL BE
DOMINATED BY A SLOW MOVING FRONT...SIMILAR TO HOW THE PATTERN HAS
GONE THIS WEEK. A WARM FRONT SHOULD LIFT FROM SOUTH TO NORTH
ACROSS THE REGION SUNDAY NIGHT...BUT NO MODELS ARE SHOWING ANY
PRECIPITATION WITH THE FRONT. COLD FRONT WILL THEN SLIP SOUTH
ACROSS MICHIGAN AND LAKE ERIE TOWARDS OHIO. GFS AND ITS ENSEMBLE
SEEM TO BE FASTER THAN ALL OTHER MODELS BRINGING THE ASSOCIATED
PRECIP INTO EASTERN OH/WESTERN PA ON MONDAY...KEPT A SLIGHT CHANCE
LATE DAY. HIGHER CHANCE POPS ARRIVING MONDAY NIGHT. FRONT WILL BE
IN THE AREA TUESDAY INTO TUESDAY NIGHT...AND HAVE BUMPED UP POPS.
ENSEMBLES AND DETERMINISTIC MODELS THEN SHOW LOW PRESSURE MOVING
ACROSS MICHIGAN INTO ONTARIO...DRAGGING A COLD FRONT THROUGH THE
REGION WEDNESDAY INTO THURSDAY. IF THE FRONT TAKES THIS LONG TO
MOVE THROUGH...THERE COULD BE A EXTENDED PERIOD OF RAINFALL.
TEMPERATURES THROUGHOUT THE WEEK WILL BE ABOUT 10 DEGREES ABOVE
NORMAL.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
BEHIND THE RAIN SHIELD...CIGS WILL DROP AND REMAIN IN THE MVFR
CAT INTO EARLY AFTERNOON. IMPROVEMENT IN CONDITIONS FROM WEST TO
EAST DURING THE LATE MORNING/EARLY AFT HOURS. LATEST MODEL DATA IS
PORTRAYING AN IMPROVEMENT TO VFR CIGS AT ALL PORTS EXCEPT FKL AND
DUJ WHICH WILL REMAIN IN MVFR CIGS.
SFC WINDS WILL INCREASE AND VEER BEHIND FRONT WITH WESTERLY WINDS OF
10 TO 15 MPH WITH GUSTS TO 25.
.OUTLOOK.../SATURDAY THROUGH TUESDAY/...
CIG RESTRICTIONS WILL REMAIN POSSIBLE IN CAA SATURDAY. AN
IMPROVEMENT TO VFR SATURDAY NIGHT THROUGH SUNDAY NIGHT AS HIGH
PRESSURE RIDGE BRIEFLY ENTERS THE REGION. A WEAK FRONT COULD BRING
SOME SCATTERED SHOWERS MONDAY INTO TUESDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
448 PM EDT FRI APR 12 2013
.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 445 PM EDT FRI APR 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL LOW OVER NRN
WI WITH SHORTWAVE SPOKES INTO SRN UPPER MI AND WRN LAKE SUPERIOR.
WIDESPREAD LIGHT SNOW (VSBY IN THE 1-4SM RANGE) STILL PREVAILED
ACROSS MUCH OF UPPER MI WITH THE FAVORABLE UPPER LEVEL DIV AND
700-300 MB QVECTOR CONV TO THE NORTH OF THE LOW. AT THE SFC...LOW
PRES WAS LOCATED OVER NW LOWER MI NEAR TVC WITH A TROUGH EXTENDING
TO THE EAST TO LAKE ONTARIO. WITH THE SFC-850 MB TROUGH EDGING
CLOSER TO THE AREA...THE ENE LOW LEVEL FLOW HAD DIMINISHED. EVEN
WITH 850 MB TEMPS DOWN TO AROUND -11C...RADAR SHOWED ONLY MINIMAL IF
ANY LAKE ENHANCEMENT INTO N CNTRL UPPER MI.
EXPECT LIGHT SNOW ASSOCIATED WITH THE MID LEVEL LOW TO PERSIST THIS
EVENING BUT WITH ACCUMULATIONS OF LESS THAN AN INCH. WITH THE LOW
LEVEL TROUGH AXIS SHIFTING TO NEAR E UPPER MI...LOW LEVEL CONV FOR
LAKE ENHANCED SNOW WILL BE LESS FAVORABLE THIS EVENING. HOWEVER...AS
THE TROUGH SHIFTS TO THE EAST AND WINDS BACK MORE NRLY AND STRENGTHEN
OVERNIGHT INTO SATURDAY MORNING...LAKE ENHANCED SNOW IS EXPECTED TO
BECOME HEAVIER OVER THE WEST AND THEN SHIFT INTO N CNTRL UPPER MI
LATE TONIGHT INTO SATURDAY MORNING. EVEN WITH ONLY MARGINAL 850 MB
TEMPS NEAR -12C AND LAKE INDUCED CAPES TO NEAR 300 J/KG...ABUNDANT
850-500 MB MOISTURE AND CYCLONIC LOW LEVEL FLOW WILL FAVOR AT LEAST
LIGHT TO MODERATE SNOW. SNOW/WATER RATIOS SHOULD ALSO BECOME MORE
FAVORABLE WITH SIGNIFICANT UPWARD MOTION IN THE 850-750 MB DGZ LAYER.
EVEN WITH THE SNOW TAPERING OFF FOR A TIME TONIGHT...THE ADVISORIES
OVER THE NW HALF WERE EXTENDED INTO SATURDAY WITH HIGHER SNOWFALL
RATES AGAIN DEVELOPING. ADDITIONAL AMOUNTS FROM 00Z-18Z SHOULD STILL
REMAIN IN THE 2 TO 6 INCH RANGE.
.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 445 PM EDT FRI APR 12 2013
THE LONG RANGE LOOKS TO FEATURE AN WX ACTIVE PATTERN WITH BLO NORMAL
TEMPS OVERALL AS MEAN UPR TROF OVER CENTRAL NAMERICA LINGERS. MAIN
FOCUS WL BE ON NEXT LO PRES DISTURBANCE PROGGED TO IMPACT THE CWA
LATE SUN THRU SUN NGT.
SAT NGT...SHRTWV RDG AXIS BTWN DEPARTING/WEAKENING CLOSED LO OVER SE
CANADA AND NEXT SHRTWV/SFC LO MOVING INTO THE NRN PLAINS IS FCST TO
BLD INTO THE GRT LKS. WITH ARRIVAL OF SFC HI PRES RDG/DRYING ALF
UNDER THE RISING HGTS...LINGERING -SHSN UNDER MORE PERSISTENT CYC NW
FLOW/DEEPER MSTR/H85 TEMPS AS LO AS -10C IN THE EVNG OVER THE
NCENTRAL AND E WL END AND GIVE WAY TO AT LEAST PARTIAL CLRG.
SUN/SUN NGT...EXPECT A DRY START TO THE DAY ON SUN WITH SFC HI PRES
RDG SLOWLY DEPARTING TO THE E. BUT ANY MRNG SUNSHINE WL QUICKLY FADE
BEHIND INCRSG CLDS AS VIGOROUS ISENTROPIC ASCENT/SW FLOW BTWN THE
DEPARTING HI AND NEXT SHRTWV/SFC LO MOVING THRU THE NRN PLAINS AND
TOWARD MN LATE ON SUN OVERSPREADS UPR MI. AS UPR DVGC/BAND OF H5-7
FGEN AHEAD OF ATTENDANT WARM FNT MOVES IN AFT 18Z...EXPECT PCPN TO
OVERSPREAD THE CWA BY 00Z MON. PTYPE WL BE A CONCERN AT THE ONSET OF
THE PCPN EVENT 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. IN FACT...THESE
FCST SDNGS ALSO SUG PCPN MAY BE AT LEAST MIXED WITH SOME ZR FOR A
TIME LATE IN THE AFTN/EVNG OVER AT LEAST THE HIER TERRAIN OF THE W
HALF. 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 MOS TEMPS SEEM MORE APPROPRIATE FOR THE TEMPS 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 50-60KTS 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
TEMPS REMAINING BLO 0C THERE FOR A LONGER TIME. NEGATIVELY TILTED
APPEARANCE OF SHRTWV/VERY DIFFLUENT SW FLOW ALF/MSTR SURGE WITH PWAT
FCST UP TO 1 INCH SUN EVNG...OR 200 PCT OF NORMAL...INDICATE QPF
NEARING 1 INCH IS ON TRACK. RUNOFF FM THIS RA IN THE PRESENCE OF
LINGERING SN PILES MAY CAUSE SOME PONDING OF WATER. CONSIDERED
ADDING A CHC OF ELEVATED TS UNDER THE MOST IMPRESSIVE
MOISTENING/AXIS OF H85 LLJ...BUT FCST SDNGS SHOW H85-5 LAPSE RATES
NOT QUITE MOIST ADIABATIC. ARRIVAL OF DRY SLOT SUN NGT WL DIMINISH
POPS SW-NE AFTER THE EVNG.
MON...DRY SLOT ON THE SRN FLANK OF SHRTWV/SFC LO TRACKING ENEWD THRU
SRN ONTARIO WL END ANY LINGERING PCPN OVER THE E AND SCNTRL
ASSOCIATED WITH DEPARTING WARM CONVEYOR BELT. THE GFS IS MOST
AGGRESSIVE AT SHOWING SOME DEEPER MSTR/PCPN ON THE SE FLANK OF THE
UPR LO IMPACTING THE WRN ZNS...BUT BULK OF GUIDANCE INDICATES DEEPER
MSTR/PCPN WL REMAIN IN MN CLOSER TO LINGERING LO PRES TROF ON SW
FLANK OF LO DEPARTING TO THE NE. EXPECT AT LEAST PARTIAL SUNSHINE...
WHICH SHOULD BOOST MAX TEMPS INTO THE 40S AT MOST PLACES WITH H85
TEMPS FCST JUST A COUPLE DEGREES BLO 0C.
EXTENDED...DRYING/LLVL ACYC FLOW UNDER SLOWLY RISING HGTS BTWN
DEPARTING LO AND DEEPENING TROF IN THE ROCKIES WL BRING DRY WX AND
SEASONABLE TEMPS FOR MON NGT THRU TUE NGT. AS LO PRES LIFTS NEWD OUT
OF THE WRN TROF AND TOWARD THE GRT LKS ON WED INTO THU...ANOTHER
SGNFT MIXED PCPN EVENT APPEARS LIKELY. IF THE WELL CLUSTERED 00Z
ECMWF...CNDN...AND UKMET VERIFY...THE PTYPE WOULD BE MAINLY SN OVER
THE W HALF OF THE CWA WITH WARNING SN TOTALS LIKELY. THE 00Z/06Z/12Z
GFS ON THE OTHER HAND SHOWS A MUCH WEAKER LO TRACKING FARTHER TO THE
S AND MUCH LESS PCPN IMPACTING MAINLY THE SE HALF OF UPR MI. ALL
THESE SCENARIOS ARE WITHIN THE SPREAD SHOWN BY THE 00Z GFS ENSEMBLE
MEMBERS. COLDER AIR WITH SHSN WL FOLLOW ON FRI AS THE 00Z ECMWF
SHOWS H85 TEMPS TUMBLING TO -15C UNDER CYC NW FLOW LEFT IN THE WAKE
OF DEPARTING LO PRES.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 150 PM EDT FRI APR 12 2013
EXPECT SCATTERED TO NUMEROUS SNOW SHOWERS THIS AFTERNOON INTO THIS
EVENING WITH VARIABLE VISIBILITIES WILL LIKELY BE BOUNCING BETWEEN 1
AND 4 MILES. FROM THIS AFTERNOON INTO THIS EVENING...LAKE
INFLUENCES WILL ENHANCE THE SNOW AT KCMX/KSAW AT TIMES. AS THE UPPER
LOW IS OVERHEAD AND THE SURFACE LOW MOVES NORTHEAST INTO
CANADA...WINDS WILL TURN MORE NORTHERLY TONIGHT AND LEAD MAINLY LAKE
ENHANCED SNOWFALL FOR ALL THREE SITES. VISIBILITIES WERE KEPT DOWN
DURING THAT PERIOD AND ALSO LOWERED CEILINGS DUE TO WINDS BECOMING
MORE FAVORABLE TO UPSLOPE. THE SNOW SHOULD TAPER OFF SATURDAY BUT
WILL LIKELY REMAIN IN THE LOWER MVFR RANGE INTO THE EARLY AFTERNOON.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 445 PM EDT FRI APR 12 2013
AS LOW PRESSURE OVER LOWER MICHIGAN SLIDES TO THE EAST TONIGHT AND
SATURDAY...WINDS WILL DIMINISH. THIS OCCURS...WINDS WILL GRADUALLY
SHIFT TO THE NORTH-NORTHWEST THROUGH SATURDAY AS A LINGERING SURFACE
TROUGH ROTATES THROUGH LAKE SUPERIOR. ENE GALES LATE THIS AFTERNOON
WILL DIMINISH TO 20 TO 30 KT WINDS TONIGHT AND INTO THE 15 TO 25 KT
RANGE SATURDAY.
WINDS ON SAT NIGHT WILL TURN LIGHT WITH THE ARRIVAL OF A HI PRES
RIDGE. EXPECT INCREASING E WINDS UP TO 25 TO 30 KTS VEERING TO THE
SE ON SUN INTO SUN NIGHT AHEAD OF A LO PRES SYSTEM MOVING FROM THE
NORTHERN PLAINS TOWARD MN. AS THIS LO PASSES THRU ONTARIO ON MON/MON
NIGHT AND THE PRES GRADIENT OVER LAKE SUP DIMINISHES...THE WINDS
WILL SUBSIDE WHILE VEERING TO THE S AND THEN W INTO TUE. EXPECT THE
WINDS TO SHIFT TO THE N BY WED AS HI PRES BUILDS IN CENTRAL CANADA
AND ANOTHER LO PRES SYSTEM MOVES NE THRU THE PLAINS.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 2 PM EDT SATURDAY FOR MIZ004-005.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT /7 AM CDT/ SATURDAY FOR
MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 11 AM EDT SATURDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ084.
LAKE SUPERIOR...
GALE WARNING UNTIL 5 PM EDT THIS AFTERNOON FOR LSZ264-266.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KC
AVIATION...JLB
MARINE...JLB/KC
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
152 PM EDT FRI APR 12 2013
.UPDATE...
ISSUED AT 1243 PM EDT FRI APR 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED THAT THE MID/UPPER LEVEL LOW
HAVE MOVED INTO CNTRL WI. ONE SHORTWAVE SPOKE WAS LIFTING THROUGH NW
UPPER MI SUPPORTED LIGHT TO MODERATE SNOW WHILE FORCING CLOSER TO
THE LOW HAS KEPT -SN GOING FROM NRN WI INTO SRN WI WITH VSBY INTO
THE 1SM TO 3SM RANGE. RADAR INDICATED THAT THE SNOW OVER THE ERN
CWA HAD DIMINISHED. ADDITIONAL ACCUMULATIONS OF ONLY AROUND AN INCH
ARE EXPECTED OVER THE SOUTH AND LESS THAN AN INCH OVER THE EAST.
SO...THE WINTER STORM WARNINGS WERE DROPPED OVER THE EAST AND THE
ADVISORY FOR DICKINSON/IRON WILL BE ALLOWED TO EXPIRE AT 18Z. THE
WARNINGS OVER FROM MARQUETTE INTO THE KEWEENAW WERE TRANSITIONED TO
WINTER WEATHER ADVISORIES FOR A MORE PROLONGED PERIOD OF LIGHT TO
MODERATE SNOW INTO SATURDAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 540 AM EDT FRI APR 12 2013
INITIAL BATCH OF HEAVY SNOW IS MOVING NORTH ACROSS NORTH CENTRAL AND
EASTERN UPPER MICHIGAN AT THIS TIME. THIS IS ASSOCIATED WITH THE
TROWAL FEATURE...SEEN ON 290-315K SFCS...THAT PIVOTS NORTHEAST AND
BEST FORCING SLIDES OFF TO THE EAST THIS MORNING INTO EARLY
AFTERNOON. WOULD EXPECT THE HEAVIEST SNOW TO OCCUR OVER THE NORTH
CENTRAL OVER THE NEXT COUPLE OF HOURS BEFORE THE DRIER MID LEVEL AIR
SEEN ON WATER VAPOR IMAGERY AND GAP BETWEEN THE UPPER LOW AND
INITIAL SHORTWAVE MOVES IN. FARTHER EAST...THERE IS A LITTLE MORE OF
A FETCH WITH THE CLOSER PROXIMITY TO THE DEEPER MOISTURE AXIS MOVING
THROUGH LOWER MICHIGAN AND WOULD EXPECT THE HEAVIER SNOW TO CONTINUE
LONGER INTO THE MORNING HOURS. BUT THEN WITH THE DRIER AIR MOVING IN
BY LATE MORNING...THE SNOW SHOULD QUICKLY DIMINISH FROM SOUTH TO
NORTH THIS AFTERNOON.
TODAY WILL START THE TRANSITION TO A MORE GENERAL LIGHTER SNOW
ACROSS THE CWA...AS THE HEAVIER SNOW SHIFTS TO THE NORTHEAST. THE
UPPER LOW CURRENTLY OVER SOUTHEAST MN AND NORTHEAST IOWA IS EXPECTED
TO ROTATE NORTHEAST AND OVER THE UPPER GREAT LAKES THIS AFTERNOON
AND TONIGHT. EVEN WITH THE TROWAL FEATURE SHIFTING OUT EARLY THIS
MORNING...BROAD 850-500MB Q-VECTOR CONVERGENCE OVER THE AREA THIS
MORNING AHEAD OF THE SHORTWAVE ENERGY MOVING NORTH THROUGH CENTRAL
WISCONSIN SHOULD STILL LEAD TO LIGHT TO OCCASIONALLY MODERATE
SNOWFALL BEHIND THE HEAVIER SNOW. THIS Q-VECTOR CONVERGENCE STAYS
OVER THE NORTHERN HALF OF THE CWA THROUGH THIS AFTERNOON AND
TONIGHT. FARTHER SOUTH...THE LINE OF CONVECTIVE LOOKING SHOWERS ON
THE NORTH SIDE OF THE SHORTWAVE MOVING NORTH THROUGH WISCONSIN
SHOULD GRADUALLY SHIFT NORTH THROUGH THE DAY AND COULD LEAD TO BRIEF
HEAVIER SNOW SHOWERS OVER SOUTHERN UPPER MICHIGAN...ESPECIALLY SINCE
IT LOOKS TO COMBINE DEFORMATION AREA ON THE NW SIDE OF THE LOW
MOVING INTO THE LOWER GREAT LAKES. FINALLY...DID ADD A MENTION OF
FREEZING DRIZZLE OVER THE SOUTH CENTRAL FOR THIS MORNING WITH THE
MID LEVEL DRYING SEEN ON WV IMAGERY REMOVING ICE CRYSTALS IN THE
CLOUD FOR A PERIOD. KGRB REPORTED FREEZING RAIN FOR A PERIOD AS THAT
MOVED THROUGH THAT AREA AND SEEING BR AT KIMT. THINK THIS WILL BE
SHORT LIVED AS THE DEEPER MOISTURE ARRIVES FROM THE UPPER LOW.
THE OTHER FACTOR FOR SNOW OVER THE KEWEENAW AND NORTH CENTRAL TODAY
AND NORTH WIND BELTS IN THE WEST/CENTRAL TONIGHT WILL BE LAKE
ENHANCEMENT. DEEP MOISTURE...CYCLONIC FLOW AND 850MB TEMPS TO AROUND
-11C AND 800MB TEMPS OF -15C WILL LEAD TO ENOUGH INSTABILITY FOR
LAKE ENHANCEMENT AND THE LOCATION/TIMING COMES DOWN TO THE WINDS AND
HOW THEY SLOWLY BACK TODAY INTO TONIGHT. WITH THOSE
TEMPERATURES...LAKE INDUCED CAPES ARE NOT OVERLY
IMPRESSIVE...GENERALLY IN THE 100-200 J/KG RANGE...SO WOULDN/T
EXPECT THE LAKE ENHANCEMENT TO GET TOO OUT OF HAND. IT WILL PROBABLY
BE MORE OF A COMBINED EFFORT BETWEEN THE LAKE ENHANCEMENT AND THE
TERRAIN ENHANCEMENT AS THE WINDS BACK NORTHEAST THIS AFTERNOON
AND NORTHERLY INTO TONIGHT. PROBABLY THE BEST LOCATION FOR THOSE
COMBINED FACTORS WILL BE OVER THE HIGHER TERRAIN OF NORTHERN
MARQUETTE/BARAGA COUNTIES...ESPECIALLY SINCE THE WINDS WILL BE A
SLIGHTLY UNFAVORABLE NORTHEAST WIND DIRECTION FOR THE KEWEENAW LATE
THIS AFTERNOON AND TONIGHT. FARTHER EAST...WINDS WILL BE MORE
VARIABLE OVER ALGER/LUCE THIS AFTERNOON AND EVENING AFTER THE
INITIAL PUSH OF SNOW MOVES NORTH. SO THEY WILL LIKELY SEE A LULL
UNTIL THE ENHANCEMENT INCREASES OVERNIGHT AS THE WINDS TURN MORE
NORTH-NORTHWEST.
HAVE MADE SOME MINOR ADJUSTMENTS FOR SNOWFALL AMOUNTS AND TIMING
FOR TODAY...BUT THE GENERAL IDEA FOR THE FORECAST IS SIMILAR. SNOW
RATIOS WILL BE AROUND 10-12 TO 1 TODAY AND THEN TRANSITIONING
TOWARDS 15-20 TO 1 TONIGHT AS COLDER AND ARRIVES AND BETTER FORCING
IS WITHIN THE DGZ. HAVE THE HIGHEST AMOUNTS THIS MORNING OVER THE
EAST...THE HIGHER TERRAIN OF MARQUETTE COUNTY AND KEWEENAW WITH THE
INITIAL HEAVIER BATCH MOVING THROUGH. THEN THIS AFTERNOON...IT WILL
LIKELY BE FOCUSED MORE OVER THE KEWEENAW AND HIGHER TERRAIN OF
MARQUETTE/BARAGA AS WINDS SHIFT MORE NORTHWEST. THOSE AREAS WILL
PROBABLY SEE 2-5IN OF ADDITIONAL ACCUMULATION DURING THE DAY AND
1-4 TONIGHT. ELSEWHERE...1-4 INCH AMOUNTS ARE EXPECTED TODAY.
WILL LEAVE HEADLINES AS IS AT THIS TIME. DID EXTEND
ONTONAGON/GOGEBIC INTO TONIGHT WITH THE LAKE ENHANCEMENT AND LOW END
ADVISORY AMOUNTS. ONCE MUCH OF THE HEAVIER SNOW SHIFTS TO THE NORTH
THIS MORNING...MAY HAVE TO THINK ABOUT A TRANSITION TO MORE
ADVISORIES VS WARNINGS BASED OFF EXPECTED SNOWFALL AMOUNTS...BUT
THAT IS PROBABLY MORE SEMANTICS FOR THE GENERAL PUBLIC. PLUS...WITH
24 HOUR AMOUNTS APPROACHING WARNING TOTALS...IT MAY BE LESS
CONFUSING TO JUST KEEP THEM AS IS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 540 AM EDT FRI APR 12 2013
NAM SHOWS A CLOSED 500 MB LOW OVER THE U.P. NEAR MARQUETTE 12Z SAT.
THIS CLOSED LOW HEADS SLOWLY EAST THE NEAR SAULT STE MARIE 00Z SUN.
NEXT TROUGH THEN ARRIVES SUN NIGHT INTO MONDAY TO AFFECT THE AREA.
GFS...NAM AND ECMWF SHOW 850-500 MB Q-VECTOR CONVERGENCE MOVING IN
LATE SUN WHICH MOVES THROUGH SUN NIGHT ACROSS THE AREA. THIS NEXT
SYSTEM LOOKS TO HAVE SOME STRONG DYNAMICS WITH IT AS WELL ALONG WITH
PLENTY OF MOISTURE AND THINKING IS QPF WILL BE ANYWHERE FROM 0.60 TO
0.90 INCH ACROSS THE CWA FROM SUN AFTERNOON THROUGH SUN NIGHT. WE
STAY ON THE WARMER SIDE OF THIS SYSTEM WHICH MAKES IT TOUGHER TO
FORECAST PRECIPITATION. LOOKS LIKE PCPN WOULD START OFF AS SNOW SUN
AFTERNOON AND THEN WARMING WOULD OCCUR ALLOWING A RAIN/SNOW MIX SUN
NIGHT ACROSS ALL BUT THE FAR NORTH AND FAR WEST WHERE THE COLDER AIR
WOULD STAY...THEN GO TO RAIN ON MON. BECAUSE OF THIS...SNOW RATIOS
DO NOT LOOK VERY HIGH AND ANY SNOW THAT DOES FALL WOULD BE A HEAVY
AND WET SNOW. COULD SEE FROM SUN AFTERNOON THROUGH SUN NIGHT A TRACE
UP TO 4 INCHES ACROSS THE CWA WITH TRACE AMOUNTS ACROSS THE FAR
SOUTH TO 4 INCHES IN THE TIP OF THE KEWEENAW WITH MOST OF THE CWA
ANYWHERE FROM A TRACE TO 1.5 INCHES. MAIN PROBLEM IS GOING TO BE THE
QPF THOUGH AND MOST OF THIS RAIN WILL GET SOAKED INTO THE SNOWCOVER.
WITH PLENTY OF MOISTURE AROUND...WENT CATEGORICAL POPS SUN AFTERNOON
INTO SUN NIGHT FOR THE CWA. DID KEEP IT DRY FOR SUN MORNING THOUGH.
BEFORE THAT...COULD GET A LITTLE LAKE ENHANCEMENT PCPN FOR SAT NIGHT
AS 850 MB TEMPERATURES ARE AROUND -8C OR SO AND THE WRAPAROUND
MOISTURE DOES MOVE OUT THEN. DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST FOR TEMPERATURES OR WEATHER. WILL NOT GET TOO FANCY
ON WEATHER TYPES EITHER AND A RAIN/SNOW MIX FOR SUN AFTERNOON
THROUGH SUN NIGHT LOOKS GOOD.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW OVER
NORTHERN MN 12Z MON WITH A SHORTWAVE RIDGE OVER THE EASTERN U.S.
AND A BROAD 500 MB TROUGH OVER THE WESTERN U.S. THE CLOSED 500 MB
LOW HEADS NORTHEASTWARD ON TUE WITH A DIGGING TROUGH IN THE WESTERN
U.S. THIS TROUGH CONTINUES TO HEAD SLOWLY EAST 12Z WED INTO THE
ROCKIES AND THE TROUGH MOVES INTO THE NORTHERN PLAINS 12Z THU.
PATTERN CONTINUES TO LOOK COLD AND ACTIVE WITH TEMPERATURES BELOW
NORMAL WITH ABOVE NORMAL PRECIPITATION THIS EXTENDED FORECAST
PERIOD. LOOKS LIKE ANOTHER BIG STORM FOR WED NIGHT INTO THU AND POPS
ARE HIGHER DURING THAT TIME PERIOD FOR THIS. RAIN/SNOW MIX LOOKS TO
HAPPEN AT THAT TIME.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 150 PM EDT FRI APR 12 2013
EXPECT SCATTERED TO NUMEROUS SNOW SHOWERS THIS AFTERNOON INTO THIS
EVENING WITH VARIABLE VISIBILITIES WILL LIKELY BE BOUNCING BETWEEN 1
AND 4 MILES. FROM THIS AFTERNOON INTO THIS EVENING...LAKE
INFLUENCES WILL ENHANCE THE SNOW AT KCMX/KSAW AT TIMES. AS THE UPPER
LOW IS OVERHEAD AND THE SURFACE LOW MOVES NORTHEAST INTO
CANADA...WINDS WILL TURN MORE NORTHERLY TONIGHT AND LEAD MAINLY LAKE
ENHANCED SNOWFALL FOR ALL THREE SITES. VISIBILITIES WERE KEPT DOWN
DURING THAT PERIOD AND ALSO LOWERED CEILINGS DUE TO WINDS BECOMING
MORE FAVORABLE TO UPSLOPE. THE SNOW SHOULD TAPER OFF SATURDAY BUT
WILL LIKELY REMAIN IN THE LOWER MVFR RANGE INTO THE EARLY AFTERNOON.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 540 AM EDT FRI APR 12 2013
A LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES REGION TODAY
WILL CONTINUE TO PRODUCE GALE FORCE GUSTS TO 35-40KTS THROUGH THIS
THIS AFTERNOON BEFORE THE PRESSURE GRADIENT BEGINS TO WEAKEN LATE
THIS AFTERNOON AND EVENING AS THE LOW MOVES INTO WESTERN QUEBEC BY
SUNDAY MORNING. WHILE THIS OCCURS...WINDS WILL GRADUALLY SHIFT TO
THE NORTH-NORTHWEST THROUGH SATURDAY AS A LINGERING SURFACE TROUGH
ROTATES THROUGH LAKE SUPERIOR. HIGH PRESSURE WILL KEEP WINDS LIGHT
FOR SATURDAY NIGHT AND SUNDAY MORNING...BUT ANOTHER LOW PRESSURE
SYSTEM APPROACHING THE UPPER GREAT LAKES FROM THE NORTHERN PLAINS
WILL BRING INCREASING EASTERLY WINDS SUNDAY AFTERNOON INTO SUNDAY
NIGHT. A FEW GALES TO 35KTS ARE POSSIBLE ON SUNDAY NIGHT OVER THE
EASTERN LAKE. THIS LOW WILL SHIFT NORTHEAST TO JAMES BAY ON MONDAY
NIGHT AND EVENTUALLY SHIFT WINDS AROUND TO THE NORTHWEST ON MONDAY
NIGHT INTO TUESDAY. LARGE HIGH PRESSURE IN SOUTHERN CANADA WILL
BRING DECREASING WINDS TO THE AREA INTO WEDNESDAY...AS A RIDGE MOVES
INTO THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM EDT SATURDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MIZ010-
011.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT /7 AM CDT/ SATURDAY FOR
MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 2 PM EDT SATURDAY FOR MIZ004-005.
WINTER WEATHER ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ084.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>248-265-
267.
GALE WARNING UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-
263-264-266.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLB
SHORT TERM...SRF
LONG TERM...07
AVIATION...JLB
MARINE...SRF
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1244 PM EDT FRI APR 12 2013
.UPDATE...
ISSUED AT 1243 PM EDT FRI APR 12 2013
WV IMAGERY AND RUC ANALYSIS INDICATED THAT THE MID/UPPER LEVEL LOW
HAVE MOVED INTO CNTRL WI. ONE SHORTWAVE SPOKE WAS LIFTING THROUGH NW
UPPER MI SUPPORTED LIGHT TO MODERATE SNOW WHILE FORCING CLOSER TO
THE LOW HAS KEPT -SN GOING FROM NRN WI INTO SRN WI WITH VSBY INTO
THE 1SM TO 3SM RANGE. RADAR INDICATED THAT THE SNOW OVER THE ERN
CWA HAD DIMINISHED. ADDITIONAL ACCUMULATIONS OF ONLY AROUND AN INCH
ARE EXPECTED OVER THE SOUTH AND LESS THAN AN INCH OVER THE EAST.
SO...THE WINTER STORM WARNINGS WERE DROPPED OVER THE EAST AND THE
ADVISORY FOR DICKINSON/IRON WILL BE ALLOWED TO EXPIRE AT 18Z. THE
WARNINGS OVER FROM MARQUETTE INTO THE KEWEENAW WERE TRANSITIONED TO
WINTER WEATHER ADVISORIES FOR A MORE PROLONGED PERIOD OF LIGHT TO
MODERATE SNOW INTO SATURDAY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 540 AM EDT FRI APR 12 2013
INITIAL BATCH OF HEAVY SNOW IS MOVING NORTH ACROSS NORTH CENTRAL AND
EASTERN UPPER MICHIGAN AT THIS TIME. THIS IS ASSOCIATED WITH THE
TROWAL FEATURE...SEEN ON 290-315K SFCS...THAT PIVOTS NORTHEAST AND
BEST FORCING SLIDES OFF TO THE EAST THIS MORNING INTO EARLY
AFTERNOON. WOULD EXPECT THE HEAVIEST SNOW TO OCCUR OVER THE NORTH
CENTRAL OVER THE NEXT COUPLE OF HOURS BEFORE THE DRIER MID LEVEL AIR
SEEN ON WATER VAPOR IMAGERY AND GAP BETWEEN THE UPPER LOW AND
INITIAL SHORTWAVE MOVES IN. FARTHER EAST...THERE IS A LITTLE MORE OF
A FETCH WITH THE CLOSER PROXIMITY TO THE DEEPER MOISTURE AXIS MOVING
THROUGH LOWER MICHIGAN AND WOULD EXPECT THE HEAVIER SNOW TO CONTINUE
LONGER INTO THE MORNING HOURS. BUT THEN WITH THE DRIER AIR MOVING IN
BY LATE MORNING...THE SNOW SHOULD QUICKLY DIMINISH FROM SOUTH TO
NORTH THIS AFTERNOON.
TODAY WILL START THE TRANSITION TO A MORE GENERAL LIGHTER SNOW
ACROSS THE CWA...AS THE HEAVIER SNOW SHIFTS TO THE NORTHEAST. THE
UPPER LOW CURRENTLY OVER SOUTHEAST MN AND NORTHEAST IOWA IS EXPECTED
TO ROTATE NORTHEAST AND OVER THE UPPER GREAT LAKES THIS AFTERNOON
AND TONIGHT. EVEN WITH THE TROWAL FEATURE SHIFTING OUT EARLY THIS
MORNING...BROAD 850-500MB Q-VECTOR CONVERGENCE OVER THE AREA THIS
MORNING AHEAD OF THE SHORTWAVE ENERGY MOVING NORTH THROUGH CENTRAL
WISCONSIN SHOULD STILL LEAD TO LIGHT TO OCCASIONALLY MODERATE
SNOWFALL BEHIND THE HEAVIER SNOW. THIS Q-VECTOR CONVERGENCE STAYS
OVER THE NORTHERN HALF OF THE CWA THROUGH THIS AFTERNOON AND
TONIGHT. FARTHER SOUTH...THE LINE OF CONVECTIVE LOOKING SHOWERS ON
THE NORTH SIDE OF THE SHORTWAVE MOVING NORTH THROUGH WISCONSIN
SHOULD GRADUALLY SHIFT NORTH THROUGH THE DAY AND COULD LEAD TO BRIEF
HEAVIER SNOW SHOWERS OVER SOUTHERN UPPER MICHIGAN...ESPECIALLY SINCE
IT LOOKS TO COMBINE DEFORMATION AREA ON THE NW SIDE OF THE LOW
MOVING INTO THE LOWER GREAT LAKES. FINALLY...DID ADD A MENTION OF
FREEZING DRIZZLE OVER THE SOUTH CENTRAL FOR THIS MORNING WITH THE
MID LEVEL DRYING SEEN ON WV IMAGERY REMOVING ICE CRYSTALS IN THE
CLOUD FOR A PERIOD. KGRB REPORTED FREEZING RAIN FOR A PERIOD AS THAT
MOVED THROUGH THAT AREA AND SEEING BR AT KIMT. THINK THIS WILL BE
SHORT LIVED AS THE DEEPER MOISTURE ARRIVES FROM THE UPPER LOW.
THE OTHER FACTOR FOR SNOW OVER THE KEWEENAW AND NORTH CENTRAL TODAY
AND NORTH WIND BELTS IN THE WEST/CENTRAL TONIGHT WILL BE LAKE
ENHANCEMENT. DEEP MOISTURE...CYCLONIC FLOW AND 850MB TEMPS TO AROUND
-11C AND 800MB TEMPS OF -15C WILL LEAD TO ENOUGH INSTABILITY FOR
LAKE ENHANCEMENT AND THE LOCATION/TIMING COMES DOWN TO THE WINDS AND
HOW THEY SLOWLY BACK TODAY INTO TONIGHT. WITH THOSE
TEMPERATURES...LAKE INDUCED CAPES ARE NOT OVERLY
IMPRESSIVE...GENERALLY IN THE 100-200 J/KG RANGE...SO WOULDN/T
EXPECT THE LAKE ENHANCEMENT TO GET TOO OUT OF HAND. IT WILL PROBABLY
BE MORE OF A COMBINED EFFORT BETWEEN THE LAKE ENHANCEMENT AND THE
TERRAIN ENHANCEMENT AS THE WINDS BACK NORTHEAST THIS AFTERNOON
AND NORTHERLY INTO TONIGHT. PROBABLY THE BEST LOCATION FOR THOSE
COMBINED FACTORS WILL BE OVER THE HIGHER TERRAIN OF NORTHERN
MARQUETTE/BARAGA COUNTIES...ESPECIALLY SINCE THE WINDS WILL BE A
SLIGHTLY UNFAVORABLE NORTHEAST WIND DIRECTION FOR THE KEWEENAW LATE
THIS AFTERNOON AND TONIGHT. FARTHER EAST...WINDS WILL BE MORE
VARIABLE OVER ALGER/LUCE THIS AFTERNOON AND EVENING AFTER THE
INITIAL PUSH OF SNOW MOVES NORTH. SO THEY WILL LIKELY SEE A LULL
UNTIL THE ENHANCEMENT INCREASES OVERNIGHT AS THE WINDS TURN MORE
NORTH-NORTHWEST.
HAVE MADE SOME MINOR ADJUSTMENTS FOR SNOWFALL AMOUNTS AND TIMING
FOR TODAY...BUT THE GENERAL IDEA FOR THE FORECAST IS SIMILAR. SNOW
RATIOS WILL BE AROUND 10-12 TO 1 TODAY AND THEN TRANSITIONING
TOWARDS 15-20 TO 1 TONIGHT AS COLDER AND ARRIVES AND BETTER FORCING
IS WITHIN THE DGZ. HAVE THE HIGHEST AMOUNTS THIS MORNING OVER THE
EAST...THE HIGHER TERRAIN OF MARQUETTE COUNTY AND KEWEENAW WITH THE
INITIAL HEAVIER BATCH MOVING THROUGH. THEN THIS AFTERNOON...IT WILL
LIKELY BE FOCUSED MORE OVER THE KEWEENAW AND HIGHER TERRAIN OF
MARQUETTE/BARAGA AS WINDS SHIFT MORE NORTHWEST. THOSE AREAS WILL
PROBABLY SEE 2-5IN OF ADDITIONAL ACCUMULATION DURING THE DAY AND
1-4 TONIGHT. ELSEWHERE...1-4 INCH AMOUNTS ARE EXPECTED TODAY.
WILL LEAVE HEADLINES AS IS AT THIS TIME. DID EXTEND
ONTONAGON/GOGEBIC INTO TONIGHT WITH THE LAKE ENHANCEMENT AND LOW END
ADVISORY AMOUNTS. ONCE MUCH OF THE HEAVIER SNOW SHIFTS TO THE NORTH
THIS MORNING...MAY HAVE TO THINK ABOUT A TRANSITION TO MORE
ADVISORIES VS WARNINGS BASED OFF EXPECTED SNOWFALL AMOUNTS...BUT
THAT IS PROBABLY MORE SEMANTICS FOR THE GENERAL PUBLIC. PLUS...WITH
24 HOUR AMOUNTS APPROACHING WARNING TOTALS...IT MAY BE LESS
CONFUSING TO JUST KEEP THEM AS IS.
.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 540 AM EDT FRI APR 12 2013
NAM SHOWS A CLOSED 500 MB LOW OVER THE U.P. NEAR MARQUETTE 12Z SAT.
THIS CLOSED LOW HEADS SLOWLY EAST THE NEAR SAULT STE MARIE 00Z SUN.
NEXT TROUGH THEN ARRIVES SUN NIGHT INTO MONDAY TO AFFECT THE AREA.
GFS...NAM AND ECMWF SHOW 850-500 MB Q-VECTOR CONVERGENCE MOVING IN
LATE SUN WHICH MOVES THROUGH SUN NIGHT ACROSS THE AREA. THIS NEXT
SYSTEM LOOKS TO HAVE SOME STRONG DYNAMICS WITH IT AS WELL ALONG WITH
PLENTY OF MOISTURE AND THINKING IS QPF WILL BE ANYWHERE FROM 0.60 TO
0.90 INCH ACROSS THE CWA FROM SUN AFTERNOON THROUGH SUN NIGHT. WE
STAY ON THE WARMER SIDE OF THIS SYSTEM WHICH MAKES IT TOUGHER TO
FORECAST PRECIPITATION. LOOKS LIKE PCPN WOULD START OFF AS SNOW SUN
AFTERNOON AND THEN WARMING WOULD OCCUR ALLOWING A RAIN/SNOW MIX SUN
NIGHT ACROSS ALL BUT THE FAR NORTH AND FAR WEST WHERE THE COLDER AIR
WOULD STAY...THEN GO TO RAIN ON MON. BECAUSE OF THIS...SNOW RATIOS
DO NOT LOOK VERY HIGH AND ANY SNOW THAT DOES FALL WOULD BE A HEAVY
AND WET SNOW. COULD SEE FROM SUN AFTERNOON THROUGH SUN NIGHT A TRACE
UP TO 4 INCHES ACROSS THE CWA WITH TRACE AMOUNTS ACROSS THE FAR
SOUTH TO 4 INCHES IN THE TIP OF THE KEWEENAW WITH MOST OF THE CWA
ANYWHERE FROM A TRACE TO 1.5 INCHES. MAIN PROBLEM IS GOING TO BE THE
QPF THOUGH AND MOST OF THIS RAIN WILL GET SOAKED INTO THE SNOWCOVER.
WITH PLENTY OF MOISTURE AROUND...WENT CATEGORICAL POPS SUN AFTERNOON
INTO SUN NIGHT FOR THE CWA. DID KEEP IT DRY FOR SUN MORNING THOUGH.
BEFORE THAT...COULD GET A LITTLE LAKE ENHANCEMENT PCPN FOR SAT NIGHT
AS 850 MB TEMPERATURES ARE AROUND -8C OR SO AND THE WRAPAROUND
MOISTURE DOES MOVE OUT THEN. DID NOT MAKE TOO MANY CHANGES TO THE
GOING FORECAST FOR TEMPERATURES OR WEATHER. WILL NOT GET TOO FANCY
ON WEATHER TYPES EITHER AND A RAIN/SNOW MIX FOR SUN AFTERNOON
THROUGH SUN NIGHT LOOKS GOOD.
IN THE EXTENDED...GFS AND ECMWF SHOW A 500 MB CLOSED LOW OVER
NORTHERN MN 12Z MON WITH A SHORTWAVE RIDGE OVER THE EASTERN U.S.
AND A BROAD 500 MB TROUGH OVER THE WESTERN U.S. THE CLOSED 500 MB
LOW HEADS NORTHEASTWARD ON TUE WITH A DIGGING TROUGH IN THE WESTERN
U.S. THIS TROUGH CONTINUES TO HEAD SLOWLY EAST 12Z WED INTO THE
ROCKIES AND THE TROUGH MOVES INTO THE NORTHERN PLAINS 12Z THU.
PATTERN CONTINUES TO LOOK COLD AND ACTIVE WITH TEMPERATURES BELOW
NORMAL WITH ABOVE NORMAL PRECIPITATION THIS EXTENDED FORECAST
PERIOD. LOOKS LIKE ANOTHER BIG STORM FOR WED NIGHT INTO THU AND POPS
ARE HIGHER DURING THAT TIME PERIOD FOR THIS. RAIN/SNOW MIX LOOKS TO
HAPPEN AT THAT TIME.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 751 AM EDT FRI APR 12 2013
THE VERY HEAVY SNOW THAT MOVED THROUGH OVERNIGHT HAS SHIFTED NORTH
OF THE TAF SITES AND NOW ALL OF THEM WILL BE INFLUENCED BY THE UPPER
LOW ROTATING NORTH FROM WISCONSIN. THIS WILL LIKELY LEAD TO
SCATTERED TO NUMEROUS SNOW SHOWERS THROUGH THE DAY AND BASED ON
UPSTREAM OBS...VISIBILITIES WILL LIKELY BE BOUNCING BETWEEN 1 AND 5
MILES WITH THE SHOWERS. AS THE DAY GOES ON...LAKE INFLUENCES WILL
ENHANCE THE SNOW AT KCMX/KSAW AT TIMES. AS THE UPPER LOW IS OVERHEAD
AND THE SURFACE LOW MOVES NORTHEAST INTO CANADA...WINDS WILL TURN
MORE NORTHERLY TONIGHT AND LEAD MAINLY LAKE ENHANCED SNOWFALL FOR
ALL THREE SITES. HAVE CONTINUED TO KEEP VISIBILITIES DOWN DURING
THAT PERIOD AND ALSO LOWERED CEILINGS DUE TO WINDS BECOMING MORE
FAVORABLE TO UPSLOPE.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 540 AM EDT FRI APR 12 2013
A LOW PRESSURE SYSTEM MOVING THROUGH THE GREAT LAKES REGION TODAY
WILL CONTINUE TO PRODUCE GALE FORCE GUSTS TO 35-40KTS THROUGH THIS
THIS AFTERNOON BEFORE THE PRESSURE GRADIENT BEGINS TO WEAKEN LATE
THIS AFTERNOON AND EVENING AS THE LOW MOVES INTO WESTERN QUEBEC BY
SUNDAY MORNING. WHILE THIS OCCURS...WINDS WILL GRADUALLY SHIFT TO
THE NORTH-NORTHWEST THROUGH SATURDAY AS A LINGERING SURFACE TROUGH
ROTATES THROUGH LAKE SUPERIOR. HIGH PRESSURE WILL KEEP WINDS LIGHT
FOR SATURDAY NIGHT AND SUNDAY MORNING...BUT ANOTHER LOW PRESSURE
SYSTEM APPROACHING THE UPPER GREAT LAKES FROM THE NORTHERN PLAINS
WILL BRING INCREASING EASTERLY WINDS SUNDAY AFTERNOON INTO SUNDAY
NIGHT. A FEW GALES TO 35KTS ARE POSSIBLE ON SUNDAY NIGHT OVER THE
EASTERN LAKE. THIS LOW WILL SHIFT NORTHEAST TO JAMES BAY ON MONDAY
NIGHT AND EVENTUALLY SHIFT WINDS AROUND TO THE NORTHWEST ON MONDAY
NIGHT INTO TUESDAY. LARGE HIGH PRESSURE IN SOUTHERN CANADA WILL
BRING DECREASING WINDS TO THE AREA INTO WEDNESDAY...AS A RIDGE MOVES
INTO THE UPPER GREAT LAKES.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
WINTER WEATHER ADVISORY UNTIL 11 AM EDT SATURDAY FOR MIZ001-003.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR MIZ010-
011.
WINTER WEATHER ADVISORY UNTIL 8 AM EDT /7 AM CDT/ SATURDAY FOR
MIZ002-009.
WINTER WEATHER ADVISORY UNTIL 2 PM EDT SATURDAY FOR MIZ004-005.
WINTER WEATHER ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ084.
LAKE SUPERIOR...
GALE WARNING UNTIL 2 PM EDT THIS AFTERNOON FOR LSZ243>248-265-
267.
GALE WARNING UNTIL 5 PM EDT /4 PM CDT/ THIS AFTERNOON FOR LSZ162-
263-264-266.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...JLB
SHORT TERM...SRF
LONG TERM...07
AVIATION...SRF
MARINE...SRF
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
959 AM EDT FRI APR 12 2013
.SYNOPSIS...
A STORM SYSTEM AND ASSOCIATED FRONTAL ZONE WILL MOVE ACROSS THE
REGION TODAY...BRINGING A SOAKING RAIN TO MUCH OF THE AREA. THE
WEEKEND WILL REMAIN UNSETTLED...WITH SCATTERED SHOWERS...AS AN
UPPER LEVEL DISTURBANCE REMAINS IN THE VICINITY.
&&
.NEAR TERM /THROUGH TONIGHT/...
945 AM UPDATE...
WIDESPREAD RAIN ALONG WITH ISOLD THUNDER IS MVG INTO CWA AT THIS
TIME. CLOUD-GROUND LIGHTNING STRIKES REPORTED SEVERAL HRS AGO BUT
HV SINCE DISSIPATED, HOWEVER POTENTIAL EXISTS FOR IN-CLOUD
LIGHTNING ALONG WITH A RUMBLE OF THUNDER. HWVR ELEVATED CAPE
APPEARS TO BE MORE PROMINENT IN THE NEXT HR OR TWO DOWN TO THE
SOUTH AS OPPOSED TO FURTHER NORTH, THUS HV REDUCED CHC THUNDER TO
ISOLD THUNDER FOR TDA.
MODELS ARE DOING VRY POOR WITH HANDLING OF DRY SLOT WITH LATEST
HRRR DATA HANDLING THE REFLECTIVITY GRADIENT BEST. BACK EDGE HAS
MVD INTO CNTRL PA AND TIMING OF THIS WOULD PUT IT INTO SRN TIER BY
NOON WHICH IS SIMILAR TO HRRR TIMING.
AS FOR ICING, STILL SOME POTENTIAL FOR ICING AT ELEVATIONS BTWN
1600 AND 2000 FEET PER LATEST RAP BUFKIT PROFILES. MESONET SITES
IN ISOLD LOCATIONS HANGING IN THE MID-30S WITH SHELDRAKE OB IN
SULLIVAN COUNTY BLO FRZG, THO THIS SEEMS OUT OF PLACE COMPARED TO
THOSE AROUND IT. WL ALLOW WINTER WX ADVISORY TO EXPIRE AT 15Z AND
CONTINUE SPS/HWO MENTION FOR ISOLD LOCALES POSSIBLY SEEING ICING
INTO EARLY AFTN.
WINDS WL GUST TO BETWEEN 30 AND 40 MPH FOR ANOTHER HOUR OR TWO
THIS BFR PRESSURE GRADIENT RELAXES THIS AFTN. NO OTHER CHGS NEEDED
AT THIS TIME.
610 AM UPDATE...
TEMPS ACRS THE WRN CATSKILLS CONTINUE THEIR SLOW RISE...WITH ONLY
ONE MESO SITE (EAST OF MONTICELLO...LOCH SHELDRAKE) REPORTING
32/32. LATEST LAPS PROFILES SUGGEST MAIN POTNL FOR ICING WOULD BE
IN A LAYER ROUGHLY FROM AROUND 1700-2200 FT. GIVEN THE OBSERVED
TRENDS...AND WITH PCPN NOT REACHING THE AREA FOR A FEW MORE
HRS...WE`LL LET FCST RIDE (NO NEW HEADLINES). ICING POTNL IS
DISCUSSED IN THE HWO...AND SPS MAY BE ISSUED LATER IF NEEDED FOR
ISOLATED ICING POTNL. PREV BLO...
COMPLICATED FCST W/RESPECT TO -FZRA POTNL ACRS ERN ZONES. VARYING
SOLUTIONS FOR THE LOW LVL THERMAL FIELDS...WITH NAM AND RUC
SUGGESTING THAT FAR ERN DELAWARE AND SULLIVAN COUNTIES COULD SEE
DAMMING OF COLD AIR INTO THE EARLY AFTN HRS. HOWEVER...T/TD`S ARE
VERY MARGINAL. MDL PROFILES INDICATE COOL AIR IS VERY SHALLOW WITH
A DEEP WARM ELEVATED LAYER...SUGGESTING THAT TEMPS AND TD`S COULD
ACTUALLY RISE WITH ONSET OF PCPN...AND MAIN TREND THUS FAR FOR T/TD`S
HAS BEEN FOR A VERY SLOW RISE. ADD TO THIS A PROJECTED START TIME
OF PCPN AFTER 12Z FURTHER COMPLICATING THE ISSUE. MARGINAL SITUATION
AND AFTER MUCH DEBATE WE WILL NOT ISSUE ANY ADDITIONAL ADVISORIES THIS
PCKG BUT WILL CONTINUE TO CLOSELY MONITOR. WE WILL ALLOW CRNT
ADVISORIES TO REMAIN UP INTO THE MRNG HRS FOR NRN ONEIDA AND
OTSEGO...ALTHO PCPN HERE WILL BE SPOTTY AT BEST THROUGH THE EARLY
MRNG HRS. FLOOD WATCH WILL ALSO REMAIN IN EFFECT FOR NRN ONEIDA
COUNTY DUE TO POTNL FOR +RA AIDED BY SNOW MELT. GUSTY SE WINDS
AHEAD OF THE FNT TDA WITH G30 LIKELY SPCLY HIER ELEVATIONS. MDLS
SHOW SI`S ARPCHNG ZERO ACRS PORTIONS OF NE PA AND THE SRN
TIER...CAN`T RULE OUT ISOLD TSRA THIS AFTN BUT WILL LET DAYSHIFT
ADD IF NEEDED.
MAIN BATCH OF RAIN WILL PULL OUT OF ERN ZONES THIS AFTN. FCST AREA
WILL BE LEFT IN SW FLOW ALOFT WITH MDLS SHOWING ANOTHER S/WV
PASSING ARND 06Z TNGT. LOW CHC POPS TO ACCOUNT FOR THIS FEATURE.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
LTL CHG TO PREV FCST. S/WV`S WILL CONTINUE TO ROTATE ARND THE GT
LAKES UPR LOW...WITH MDLS INDICATING ONE FOR SAT AFTN AND ANOTHER
LATE SAT NGT AND SUN MRNG. SCT -SHRA WITH SOME -SHSN LATER AT
NGT. PSSG OF SUNDAY S/WV SHUD BEGIN A TREND OF IMPROVING
CONDITIONS...WITH HI PRES OVER THE RNG ON SUN NGT,
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US MOVES EAST
EARLY IN THE LONG TERM. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR SUNDAY NIGHT INTO MONDAY BEFORE A SLOW MOVING COLD FRONT
BRINGS RAIN SHOWERS. MUCH LIKE THIS WEEK THE FRONT WAFFLES NORTH
AND SOUTH ACROSS THE AREA TUESDAY TO THURSDAY. LATE THURSDAY
MODELS BRING A STRONG COLD FRONT AND UPPER LEVEL TROF. MODELS
TIMING MAY BE TOO FAST WITH THE DEEP TROF IN THE WEST.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
12Z UPDATE...
WET COLD FRONT IS INBOUND FOR ALL TERMINALS TODAY. SHOWERS ARE
RUNNING AHEAD OF THE FRONT THIS MORNING...AND ALSO WITH THE FRONT
ITSELF INTO AFTERNOON. THOUGH WARM AIR HAS MOVED IN AHEAD OF THE
COLD FRONT ALOFT...UNDER IT THE ATMOSPHERE REMAINS COOL AND VERY
MOIST IN THE LOWER LEVELS. VARIATIONS OF IFR TO LOW END MVFR ARE
EXPECTED AHEAD OF AND WITH THE SHOWERY COLD FRONT. WHILE
NOT EXPLICITLY IN TAFS...AN ISOLATED EMBEDDED THUNDERSTORM IS NOT
OUT OF THE QUESTION...PARTICULARLY KELM-KBGM-KAVP. EAST TO
SOUTHEAST FLOW WITH OCCASIONAL GUSTS 16-22 KTS THROUGH THE MORNING
/LIGHTER AT KELM/ WILL BECOME VARIABLE WITH COLD FRONT MID
AFTERNOON...BEFORE LIGHT NORTHWEST TO WEST TONIGHT. BEHIND COLD
FRONT...PERIOD OF DRIZZLE AND TRAPPED MOISTURE WILL PROBABLY ALLOW
IFR TO PERSIST FOR A TIME. LIGHT FLOW ALREADY BEGINS TO BACK
TOWARDS DAWN...AND DRIER AIR WILL BE TRYING TO MAKE ITS WAY
IN...WHICH SHOULD LEAD TO SOME IMPROVEMENTS. CAVEAT IS THAT WITH
GOOD AMOUNT OF RAIN TODAY...LINGERING MOISTURE COULD CAUSE THINGS
TO LINGER LONGER THAN FORECAST.
.OUTLOOK...
SAT TO SUN NGT...MAINLY VFR BUT PSBL MVFR IN MIXED SHWRS.
MON TO TUE...MVFR IN RAIN.
&&
.HYDROLOGY...
520 AM FRIDAY UPDATE...
MINOR FLOODING FOR A FEW LOCATIONS AS MENTIONED BELOW FOR TODAY INTO
SATURDAY. LARGE AREA OF RAIN WITH SLOW MOVING COLD FRONT WILL MOVE
INTO THE AREA TODAY. THIS WILL YIELD ROUGHLY HALF TO THREE
QUARTERS OF AN INCH OR SO...HIGHEST IN ONEIDA COUNTY AND ALSO
PIKE/WAYNE/SULLIVAN. FOR ONEIDA COUNTY...SOME UNMELTED SNOW AND A
SATURATED GROUND FROM RECENT RAINFALL KEEPS FLOOD WATCH IN EFFECT.
A RIVER WARNING IS ALREADY OUT FOR THE MOHAWK RIVER AND DELTA DAM
BY OUR NEIGHBOR OFFICE IN ALBANY. ALSO...TIOUGHNIOGA RIVER IN
CORTLAND IS RUNNING HIGH AND IS EXPECTED TO CREST NEAR FLOOD STAGE
TONIGHT...SO FLOOD WARNING ISSUED FOR THERE /MINOR FLOODING
EXPECTED/.
WAVERLY-SAYRE ON SUSQUEHANNA WAS EARLIER FORECAST TO CREST NEAR FLOOD
STAGE BUT EXPECTATIONS HAVE DROPPED SOMEWHAT BASED ON LATEST QPF
TRENDS...THUS NO FLOOD WARNING ANTICIPATED THERE AT THIS TIME.
THAT BEING SAID...WHILE NOT TECHNICALLY FLOODING...WATER LEVELS WILL
STILL BE NOTICEABLY ELEVATED FOR MANY AREA STREAMS.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NYZ009-037.
WINTER WEATHER ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
NYZ009-046.
&&
$$
SYNOPSIS...
NEAR TERM...PVN
SHORT TERM...
LONG TERM...TAC
AVIATION...MDP
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
959 AM CDT FRI APR 12 2013
.UPDATE...
ISSUED AT 958 AM CDT FRI APR 12 2013
BUMPED UP POPS FOR THIS MORNING AS LIGHT SNOW HAS CONTINUED TO
SPREAD ACROSS THE CWA. THINK THAT ACCUMULATIONS WILL REMAIN
LIGHT...GENERALLY UNDER AN INCH OVER ALL BUT THE FAR NORTHEASTERN
COUNTIES. FREEZING DRIZZLE HAS CONTINUED ACROSS THE VALLEY CITY
AREA SO KEPT A PATCHY MENTION IN THAT AREA FOR THE NEXT FEW HOURS.
HOWEVER...THINK THAT THE DRY LAYER ALOFT WILL CONTINUE TO SATURATE
AND WE SHOULD BE ALL SNOW BY THIS AFTERNOON. THE NORTHEASTERN
COUNTIES WILL HAVE TO BE WATCHED IN CASE MORE SNOW ACCUMULATES
THAN EXPECTED...BUT FOR NOW WILL JUST KEEP AN EYE ON IT AND NOT
INCLUDE HEADLINES.
UPDATE ISSUED AT 700 AM CDT FRI APR 12 2013
BANDS OF SNOW SHOWERS CONTINUE TO ROTATE FROM EAST TO WEST THROUGH
THE REGION...WITH THE STEADIER SNOW ACROSS THE FAR EASTERN FA.
THIS IS IN LINE WITH THE EXPECTED FORECAST.
GETTING REPORTS OF FREEZING DRIZZLE FROM COOPERSTOWN TO VALLEY
CITY. RAP 10Z SOUNDING INDICATES A DRY LAYER FROM 700MB-
500MB...WITH THE SATURATED LAYER BELOW -8C TO -10C. THIS SOUNDING
IS NOT AN IDEAL SUPERCOOLED WATER DROPLET SCENARIO...BUT IT IS
OCCURRING. THE RAP DOES SATURATE THE 700MB-500MB LAYER AFTER
15Z...WHICH SHOULD ALLOW THE P-TYPE TO BE ALL SNOW AGAIN. WILL
INCLUDE FZDZ IN THE AREA UNTIL 15Z...AND ISSUE A SPS (A FEW CARS
REPORTED TO BE IN DITCH ALONG I-94).
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 355 AM CDT FRI APR 12 2013
THE UPPER LEVEL LOW WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH
THE PERIOD. MODELS ARE IN GOOD AGREEMENT AND WILL USE A BLEND FOR
DETAILS. THE MAIN CHALLENGE FOR TODAY WILL BE SNOW CHANCES AND
AMOUNTS. UPPER LEVEL ENERGY CONTINUES TO ROTATE AROUND THE UPPER
LEVEL LOW...AND ANOTHER SHOT OF FORCING/MOISTURE IS HEADED TOWARD
THE EASTERN FA FOR THE MORNING HOURS. GIVEN UPSTREAM
OBSERVATIONS...RADAR IMAGERY...AND MODEL GUIDANCE...EXPECT AN
ADDITIONAL 2-4 INCHES OF SNOW ACROSS THE FAR EASTERN FA. SCATTERED
SNOW SHOWERS AND AN INCH OR TWO OF SNOW WILL OCCUR ALONG AND WEST
OF THE VALLEY. CLOUDS WILL HOLD STRONG TODAY...AND MAX TEMPS
SHOULD BE SIMILAR TO YESTERDAY.
THE UPPER LOW FINALLY MOVES FAR ENOUGH EAST BY SATURDAY THAT
RIDGING SHOULD BE ABLE TO MOVE INTO THE REGION. DID CLEAR SKIES ON
SATURDAY...HOPEFULLY IT ACTUALLY HAPPENS. MIN TEMPS FRIDAY NIGHT
WILL BE INFLUENCED BY CLOUDS...AND MODELS INDICATING THAT CLOUDS
WILL NOT ERODE UNTIL SATURDAY AFTER SUNRISE...SO RAISED VALUES A
FEW DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 355 AM CDT FRI APR 12 2013
SATURDAY NIGHT-SUNDAY NIGHT...THE POSSIBLE SIGNIFICANT WINTER
STORM WILL BE THE MAIN CHALLENGE. 00Z MODELS ARE ALL IN AGREEMENT
THAT THE POTENTIAL EXISTS FOR HEAVY SNOWFALL AND STRONG
WINDS...AND ARE ALL FAIRLY SIMILAR WITH SYNOPTIC FEATURES. CURRENT
WATER VAPOR IMAGERY INDICATES A VERY STRONG WAVE NEAR THE GULF OF
ALASKA. THIS WAVE WILL DIVE SOUTHEAST AND INTO THE REGION BY
SUNDAY OR SUNDAY NIGHT...STALLING ONCE IT REACHES EASTERN NORTH
DAKOTA. MODELS INDICATE A BAND OF WARM AIR ADVECTION/FRONTOGENETICAL
FORCING ACROSS THE SOUTHERN FA BY SUNDAY MORNING...LIFTING
NORTHWARD THROUGH THE DAY ON SUNDAY...WITH WIDESPREAD 0.50 TO 1.00
INCH QPF (PWATS 0.5-0.6 INCHES). SREF P-TYPE PROBABILITY AND
ECMWF THERMAL PROFILES SUGGEST THIS TO BE ALL IN THE FORM OF SNOW.
THE GFS AND GEM DO BRING A WARM LAYER INTO THE FAR SOUTHEAST FA ON
SUNDAY...BUT THIS WOULD ONLY BE FOR A BRIEF PERIOD OF TIME. USING
AROUND A 13:1 RATIO DURING THE NIGHTTIME HOURS...AND 9:1 RATIO
DURING THE DAYTIME HOURS LEADS TO WIDESPREAD 7-14 INCHES OF SNOW
(AND CANNOT RULE OUT HIGHER AMOUNTS WHERE HEAVIER BANDS SET UP).
WINDS WILL ALSO BE AN ISSUE WITH THE GFS AND ECMWF INDICATING
925MB WINDS AROUND 35 KNOTS FROM THE EAST ON SUNDAY...AND THEN
FROM THE NORTH/NORTHEAST SUNDAY NIGHT (CREATING BLOWING SNOW AND
SIGNIFICANTLY REDUCED VISIBILITY). WITH MODELS IN SUCH GOOD
AGREEMENT...AND CONSISTENT FOR THE PAST SEVERAL DAYS...WILL ISSUE
A WINTER STORM WATCH. THE EXACT TRACK OF THE SYSTEM WILL DETERMINE
WHO GETS THE MOST SNOW...AND WHERE THE STRONGEST WINDS OCCUR.
MONDAY-THURSDAY...THE UPPER LOW WILL SLOWLY SHIFT NORTHEAST INTO
ONTARIO ON MONDAY. THE FLOW PATTERN WILL REMAIN BROADLY
CYCLONIC...WITH SOME SNOW SHOWERS/FLURRIES EXPECTED. WITH COLD AIR
ADVECTION AND 925 MB WINDS BETWEEN 30-40 KTS...CONTINUED GUSTY WINDS
ARE EXPECTED...GRADUALLY DIMINISHING DURING THE DAY.
A BREAK IN THE ACTION IS EXPECTED FOR TUESDAY...WITH HIGH PRESSURE
BUILDING INTO THE REGION. A FEW SNOW SHOWERS MAY LINGER...THOUGH.
CONTINUED WEAK COLD AIR ADVECTION WILL LIKELY KEEP MOST AREAS IN THE
30S...15 TO 20 DEGREES BELOW NORMAL.
ANOTHER INTENSE PACIFIC SHORTWAVE TROUGH IS EXPECTED TO DIG SOUTH
TOWARDS THE SOUTHERN ROCKIES BY MID-WEEK...WITH THE UPPER FLOW BECOMING
SOUTHWEST ACROSS THE PLAINS. THE 00Z MODELS LIFT THIS WAVE/SFC CYCLONE
NORTHEASTWARD ALONG THE REMNANT LOW-LEVEL BAROCLINIC ZONE. THE 00Z
GFS REMAINS FARTHER SOUTH COMPARED WITH THE ECMWF. THE ECMWF WOULD
BRING ANOTHER ROUND OF SNOW TO THE AREA...GIVEN IMPRESSIVE MID/UPPER
LEVEL DYNAMICS AND ITS NORTHWARD DISPLACEMENT OF THE UPPER
LOW...DESPITE KEEPING THE SFC LOW WELL TO THE SOUTHEAST. HOWEVER...GFS
ENSEMBLE MEMBERS INDICATE PLENTY OF SPREAD IN THE 500 MB LOW
TRACK...AND OVERALL CONFIDENCE IS LOW AT THIS RANGE. WILL MAINTAIN
CHANCE POPS DURING THE WED-THU PERIOD.
LOW-LEVEL THERMAL FIELDS DO NOT CHANGE MUCH THROUGH THE
PERIOD...WITH 925 MB TEMPS GENERALLY BETWEEN ABOUT -3 AND -8C. AS A
RESULT...HIGH TEMPS SHOULD REMAIN MAINLY IN THE 30S...WITH LOWS IN
THE 20S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 700 AM CDT FRI APR 12 2013
SCATTERED SNOW SHOWERS EXPECTED THROUGH THE DAYTIME HOURS...WITH
PERIODIC DROPS TO MVFR CONDITIONS. CLOUDS WILL REMAIN THROUGH THE
OVERNIGHT HOURS...BUT UNSURE HOW LOW THEY WILL BE. GUIDANCE IS
TOO LOW WITH CURRENT CIGS...AND MOST LIKELY SCENARIO FOR THE
OVERNIGHT HOURS WILL BE LOW VFR OR HIGH MVFR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR NDZ028>030-038-039-049-052-053.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR NDZ006>008-014>016-024-026-027-054.
MN...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR MNZ002-003-022>024-027>032-040.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR MNZ001-004>009-013>017.
&&
$$
UPDATE...JR
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
700 AM CDT FRI APR 12 2013
.UPDATE...
ISSUED AT 700 AM CDT FRI APR 12 2013
BANDS OF SNOW SHOWERS CONTINUE TO ROTATE FROM EAST TO WEST THROUGH
THE REGION...WITH THE STEADIER SNOW ACROSS THE FAR EASTERN FA.
THIS IS IN LINE WITH THE EXPECTED FORECAST.
GETTING REPORTS OF FREEZING DRIZZLE FROM COOPERSTOWN TO VALLEY
CITY. RAP 10Z SOUNDING INDICATES A DRY LAYER FROM 700MB-
500MB...WITH THE SATURATED LAYER BELOW -8C TO -10C. THIS SOUNDING
IS NOT AN IDEAL SUPERCOOLED WATER DROPLET SCENARIO...BUT IT IS
OCCURRING. THE RAP DOES SATURATE THE 700MB-500MB LAYER AFTER
15Z...WHICH SHOULD ALLOW THE P-TYPE TO BE ALL SNOW AGAIN. WILL
INCLUDE FZDZ IN THE AREA UNTIL 15Z...AND ISSUE A SPS (A FEW CARS
REPORTED TO BE IN DITCH ALONG I-94).
&&
.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 355 AM CDT FRI APR 12 2013
THE UPPER LEVEL LOW WILL CONTINUE TO PROPAGATE NORTHEAST THROUGH
THE PERIOD. MODELS ARE IN GOOD AGREEMENT AND WILL USE A BLEND FOR
DETAILS. THE MAIN CHALLENGE FOR TODAY WILL BE SNOW CHANCES AND
AMOUNTS. UPPER LEVEL ENERGY CONTINUES TO ROTATE AROUND THE UPPER
LEVEL LOW...AND ANOTHER SHOT OF FORCING/MOISTURE IS HEADED TOWARD
THE EASTERN FA FOR THE MORNING HOURS. GIVEN UPSTREAM
OBSERVATIONS...RADAR IMAGERY...AND MODEL GUIDANCE...EXPECT AN
ADDITIONAL 2-4 INCHES OF SNOW ACROSS THE FAR EASTERN FA. SCATTERED
SNOW SHOWERS AND AN INCH OR TWO OF SNOW WILL OCCUR ALONG AND WEST
OF THE VALLEY. CLOUDS WILL HOLD STRONG TODAY...AND MAX TEMPS
SHOULD BE SIMILAR TO YESTERDAY.
THE UPPER LOW FINALLY MOVES FAR ENOUGH EAST BY SATURDAY THAT
RIDGING SHOULD BE ABLE TO MOVE INTO THE REGION. DID CLEAR SKIES ON
SATURDAY...HOPEFULLY IT ACTUALLY HAPPENS. MIN TEMPS FRIDAY NIGHT
WILL BE INFLUENCED BY CLOUDS...AND MODELS INDICATING THAT CLOUDS
WILL NOT ERODE UNTIL SATURDAY AFTER SUNRISE...SO RAISED VALUES A
FEW DEGREES.
.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 355 AM CDT FRI APR 12 2013
SATURDAY NIGHT-SUNDAY NIGHT...THE POSSIBLE SIGNIFICANT WINTER
STORM WILL BE THE MAIN CHALLENGE. 00Z MODELS ARE ALL IN AGREEMENT
THAT THE POTENTIAL EXISTS FOR HEAVY SNOWFALL AND STRONG
WINDS...AND ARE ALL FAIRLY SIMILAR WITH SYNOPTIC FEATURES. CURRENT
WATER VAPOR IMAGERY INDICATES A VERY STRONG WAVE NEAR THE GULF OF
ALASKA. THIS WAVE WILL DIVE SOUTHEAST AND INTO THE REGION BY
SUNDAY OR SUNDAY NIGHT...STALLING ONCE IT REACHES EASTERN NORTH
DAKOTA. MODELS INDICATE A BAND OF WARM AIR ADVECTION/FRONTOGENETICAL
FORCING ACROSS THE SOUTHERN FA BY SUNDAY MORNING...LIFTING
NORTHWARD THROUGH THE DAY ON SUNDAY...WITH WIDESPREAD 0.50 TO 1.00
INCH QPF (PWATS 0.5-0.6 INCHES). SREF P-TYPE PROBABILITY AND
ECMWF THERMAL PROFILES SUGGEST THIS TO BE ALL IN THE FORM OF SNOW.
THE GFS AND GEM DO BRING A WARM LAYER INTO THE FAR SOUTHEAST FA ON
SUNDAY...BUT THIS WOULD ONLY BE FOR A BRIEF PERIOD OF TIME. USING
AROUND A 13:1 RATIO DURING THE NIGHTTIME HOURS...AND 9:1 RATIO
DURING THE DAYTIME HOURS LEADS TO WIDESPREAD 7-14 INCHES OF SNOW
(AND CANNOT RULE OUT HIGHER AMOUNTS WHERE HEAVIER BANDS SET UP).
WINDS WILL ALSO BE AN ISSUE WITH THE GFS AND ECMWF INDICATING
925MB WINDS AROUND 35 KNOTS FROM THE EAST ON SUNDAY...AND THEN
FROM THE NORTH/NORTHEAST SUNDAY NIGHT (CREATING BLOWING SNOW AND
SIGNIFICANTLY REDUCED VISIBILITY). WITH MODELS IN SUCH GOOD
AGREEMENT...AND CONSISTENT FOR THE PAST SEVERAL DAYS...WILL ISSUE
A WINTER STORM WATCH. THE EXACT TRACK OF THE SYSTEM WILL DETERMINE
WHO GETS THE MOST SNOW...AND WHERE THE STRONGEST WINDS OCCUR.
MONDAY-THURSDAY...THE UPPER LOW WILL SLOWLY SHIFT NORTHEAST INTO
ONTARIO ON MONDAY. THE FLOW PATTERN WILL REMAIN BROADLY
CYCLONIC...WITH SOME SNOW SHOWERS/FLURRIES EXPECTED. WITH COLD AIR
ADVECTION AND 925 MB WINDS BETWEEN 30-40 KTS...CONTINUED GUSTY WINDS
ARE EXPECTED...GRADUALLY DIMINISHING DURING THE DAY.
A BREAK IN THE ACTION IS EXPECTED FOR TUESDAY...WITH HIGH PRESSURE
BUILDING INTO THE REGION. A FEW SNOW SHOWERS MAY LINGER...THOUGH.
CONTINUED WEAK COLD AIR ADVECTION WILL LIKELY KEEP MOST AREAS IN THE
30S...15 TO 20 DEGREES BELOW NORMAL.
ANOTHER INTENSE PACIFIC SHORTWAVE TROUGH IS EXPECTED TO DIG SOUTH
TOWARDS THE SOUTHERN ROCKIES BY MID-WEEK...WITH THE UPPER FLOW BECOMING
SOUTHWEST ACROSS THE PLAINS. THE 00Z MODELS LIFT THIS WAVE/SFC CYCLONE
NORTHEASTWARD ALONG THE REMNANT LOW-LEVEL BAROCLINIC ZONE. THE 00Z
GFS REMAINS FARTHER SOUTH COMPARED WITH THE ECMWF. THE ECMWF WOULD
BRING ANOTHER ROUND OF SNOW TO THE AREA...GIVEN IMPRESSIVE MID/UPPER
LEVEL DYNAMICS AND ITS NORTHWARD DISPLACEMENT OF THE UPPER
LOW...DESPITE KEEPING THE SFC LOW WELL TO THE SOUTHEAST. HOWEVER...GFS
ENSEMBLE MEMBERS INDICATE PLENTY OF SPREAD IN THE 500 MB LOW
TRACK...AND OVERALL CONFIDENCE IS LOW AT THIS RANGE. WILL MAINTAIN
CHANCE POPS DURING THE WED-THU PERIOD.
LOW-LEVEL THERMAL FIELDS DO NOT CHANGE MUCH THROUGH THE
PERIOD...WITH 925 MB TEMPS GENERALLY BETWEEN ABOUT -3 AND -8C. AS A
RESULT...HIGH TEMPS SHOULD REMAIN MAINLY IN THE 30S...WITH LOWS IN
THE 20S.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 700 AM CDT FRI APR 12 2013
SCATTERED SNOW SHOWERS EXPECTED THROUGH THE DAYTIME HOURS...WITH
PERIODIC DROPS TO MVFR CONDITIONS. CLOUDS WILL REMAIN THROUGH THE
OVERNIGHT HOURS...BUT UNSURE HOW LOW THEY WILL BE. GUIDANCE IS
TOO LOW WITH CURRENT CIGS...AND MOST LIKELY SCENARIO FOR THE
OVERNIGHT HOURS WILL BE LOW VFR OR HIGH MVFR.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR NDZ028>030-038-039-049-052-053.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR NDZ006>008-014>016-024-026-027-054.
MN...WINTER STORM WATCH FROM LATE SATURDAY NIGHT THROUGH MONDAY
MORNING FOR MNZ002-003-022>024-027>032-040.
WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY MORNING
FOR MNZ001-004>009-013>017.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...TG/MAKOWSKI
AVIATION...TG
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
944 AM EDT FRI APR 12 2013
.SYNOPSIS...
LOW PRESSURE OVER NORTHERN OHIO EARLY THIS MORNING WILL LIFT
NORTHEAST AND TAKE A COLD FRONT EAST ACROSS THE AREA. THIS WILL
END THE MAJORITY OF THE PRECIPITATION BY EARLY AFTERNOON. HIGH
PRESSURE WILL BUILD ACROSS THE LOWER OHIO VALLEY AND TN VALLEY
LATER TODAY AND THEN ACROSS THE UPPER OHIO VALLEY FOR SUNDAY.
ANOTHER FRONTAL SYSTEM WILL BE IN THE VICINITY FOR THE FIRST PART
OF THE NEW WORK WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RAIN IS EXITING THE REGION THIS MORNING. WILL CONTINUE POPS IN NW PA FOR
A FEW HOURS WITH A SHARP DECREASING TREND. MILD TEMPERATURES ARE
CONFINED TO THE EASTERN COUNTIES OF OHIO AND NW PA CURRENTLY BUT
THESE WILL COOL SEVERAL DEGREES WITH THE PASSAGE OF THE SURFACE
LOW CURRENTLY OVER NW PA. ELSEWHERE TEMPERATURES WILL RISE VERY
SLOWLY TODAY UNDER CLOUDY SKIES.
MODELS SHOW A WEAK IMPULSE MOVING THROUGH THE OHIO VALLEY THIS
AFTERNOON. THE HRRR CREATES A FAIR AMOUNT OF WEAK CONVECTIVE TYPE
PCPN OVER THE REGION LATE IN THE AFTERNOON WITH THE ARRIVAL OF THE
TOUGH AXIS. WILL INCLUDE A SLIGHT CHANCE OF SHOWERS IN THE
AFTERNOON TO REFLECT THE POSSIBILITY OF LIGHT SHOWERS OR VIRGA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/...
COOL HIGH PRESSURE MOVES TO THE LOWER OHIO VALLEY TONIGHT WITH
SOME DEGREE OF RIDGING NUDGING UP INTO OHIO. HAVE KEPT THE LOW
PRECIP CHANCES FOR THE EAST HALF...BUT AGAIN FOLLOWING FROM THIS
AFTERNOON...NOT ENTIRELY CONFIDENT WE JUST WILL NOT DRY OUT
ALTOGETHER. HAVE REMOVED THE SNOW MENTION FROM TONIGHTS
FORECAST...AS MOISTURE IS LIMITED. TONIGHT WILL BE MUCH COOLER
WITH LOWS IN THE 30S EVERYWHERE.
UPPER LOW WILL STILL BE OVER THE GREAT LAKES SATURDAY AND IT WILL
ATTEMPT TO BRING A BIT OF JET ENERGY/SHORTWAVE TROUGH ACROSS THE
LOWER LAKES. THEREFORE AGAIN KEEP THE LOW PRECIP CHANCES ACROSS
THE EAST FOR ANY SHOWER ACTIVITY. IF THERE IS INDEED BETTER
MOISTURE THIS GO AROUND...THEN NW PA MAY SEE A FEW FLAKES OF SNOW
SATURDAY NIGHT. OUR COLDEST DAY WILL BE SATURDAY WITH HIGHS FROM
THE MID 40S TO NEAR 50 AND NEAR FREEZING SAT NIGHT.
THE RECOVERY BEGINS SUNDAY AS HIGH PRESSURE MOVES TO THE UPPER
OHIO VALLEY AND WE BEGIN TO GET A WARM ADVECT PUSH OUR WAY. WILL
HAVE BUILDING RIDGING ALOFT BETWEEN SUNDAY AND MONDAY AS A TROUGH
MOVES OUT OF THE INTER-MOUNTAIN WEST AND INTO THE PLAINS. TEMPS
WILL WARM TO NEAR NORMAL. MILDER THAN PREVIOUS NIGHTS MONDAY
NIGHT.
&&
.LONG TERM /TUESDAY THROUGH THURSDAY/...
RIDGING ALOFT IS PROGGED OVER THE EASTERN HALF OF THE COUNTRY THE
FIRST HALF OF NEXT WEEK. A SERIES OF SHORT WAVES FROM THE WEST WILL
EJECT OUT ACROSS THE PLAINS STATES. A COLD FRONT WILL MAKE PROGRESS
ACROSS THE UPPER MIDWEST AND WESTERN GREAT LAKES. THE CHALLENGE
WILL BE TO SEE HOW FAR EAST THE FRONT CAN GET BEFORE IT STALLS. THE
MODELS ARE IN SOME AGREEMENT... MORE THAN WE SAW THIS PAST WEEK.
FOR NOW WE WILL GO WITH THE IDEA OF THE FRONT MAKING IT TO THE
FORECAST AREA ON TUESDAY...BECOMING NEARLY STATIONARY FOR
WEDNESDAY...AND LIKELY SHIFTING BACK NORTH ON THURSDAY AHEAD OF THE
NEXT SURFACE LOW COMING OUT OF THE MISSISSIPPI VALLEY. I HAVE NUDGED
TEMPERATURES COOLER/WARMER RELATIVE OF THE FRONT BUT BASICALLY SPLIT
THE DIFFERENCE ON HOW COOL/WARM IT COULD BE SINCE THERE IS SO MUCH
UNCERTAINTY THIS FAR IN ADVANCE.
WILL KEEP A CHANCE OF SHOWERS PRETTY MUCH EACH DAY WITH "LIKELY" BY
THURSDAY. COULD MENTION THUNDER EACH DAY BUT DECIDED TO FOCUS MAINLY
ON THURSDAY WHEN THINGS MAY BE THE MOST UNSTABLE. AGAIN...PRETTY FAR
IN THE FUTURE TO TRY AND GET SPECIFIC.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
THE SURFACE LOW PRESSURE AND COLD FRONT WILL BE EAST OF THE
FORECAST AREA MID MORNING. WINDS ARE COMING AROUND FROM THE WEST
SOUTHWEST AND WILL BECOME GUSTY AS THE DAY GOES ON. IFR CEILINGS
WILL GRADUALLY BECOME MVFR AND THEN VFR FROM WEST TO EAST AS
DRIER AIR FILTERS IN BEHIND THE SYSTEM. VISIBILITIES WILL IMPROVE
TO VFR WHEN THE RAIN ENDS. WINDS WILL BE LESS GUSTY TONIGHT. VFR
CEILINGS (035) WILL CONTINUE TONIGHT.
.OUTLOOK...NON-VFR SATURDAY...ESPECIALLY NE OH/NW PA IN THE MORNING.
NON VFR DEVELOPING TUESDAY.
&&
.MARINE...
THE SURFACE LOW WILL SLIDE ACROSS EASTERN LAKE ERIE EARLY THIS
MORNING AND WINDS ON THE LAKE WILL FINALLY SHIFT FROM THE EAST TO
THE SOUTHWEST. THERE WILL BE A SHORT LULL IN THE WIND AND WAVES THIS
MORNING AS THE WIND SHIFT OCCURS BUT WILL KEEP THE SMALL CRAFT
ADVISORY IN EFFECT AS THE SOUTHWEST WINDS WILL INCREASE TO 15 TO 25
KNOTS BY THIS AFTERNOON.
THE SOUTHWEST TO WEST WIND WILL REMAIN BRISK INTO SATURDAY...THEN
FINALLY DIMINISH AS HIGH PRESSURE BUILDS ACROSS THE LAKE ON
SATURDAY NIGHT. WINDS WILL COME AROUND FROM THE SOUTH TO SOUTHWEST
ON SUNDAY. THE NEXT COLD FRONT IS DUE BY TUESDAY.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT SATURDAY FOR LEZ142>149.
&&
$$
SYNOPSIS...OUDEMAN
NEAR TERM...LAPLANTE
SHORT TERM...OUDEMAN
LONG TERM...KOSARIK
AVIATION...KOSARIK
MARINE...KOSARIK
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
129 PM EDT FRI APR 12 2013
.SYNOPSIS...
DRY HIGH PRESSURE WILL BUILD IN FROM THE WEST AND PERSIST THROUGH
THE WEEKEND. AN UPPER LEVEL DISTURBANCE WILL MOVE ACROSS THE AREA
SUNDAY NIGHT WITH MOISTURE AND RAIN. A MOIST SOUTHERLY FLOW THEN
DEVELOPS ACROSS THE REGION THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH SATURDAY/...
AT 125 PM...TEMPS OVER THE PIEDMONT INCREASING FASTER THAN CURRENT
GRIDS INDICATE SO ADJUSTED HIGHER PER LATEST LAMP WHICH HAS CAUGHT
THE TREND. THUS...MAX TEMPS A COUPLE DEGREES HIGHER TODAY.
PREVIOUS DISCUSSION:
AT 1145 AM...DID A QUICK UPDATE FOR TEMP AND POP TRENDS. PREFRONTAL
LINE OF SHRA NOW WELL EAST OF THE AREA. ACTUAL FRONT GETTING LOST IN
LEE TROUGH DEVELOPMENT...BUT DEWPOINTS INDICATE THE FRONT IS MAKING
ITS WAY THROUGH THE NC PIDMONT AND SOUTHERN UPSTATE. LATEST HRRR
BACKING OFF ON THE IDEA OF ISOLATED SHOWERS OVER THE NC PIEDMONT
THIS AFTENROON. WITH DEWPOINTS LOWERING SHOWER DEVELOPMENT SEEMS
UNLIKLEY...SO WILL REMOVE THE MENTIONABLE POPS.
AT 10AM EDT...LATEST SURFACE ANALYSIS INDICATES THAT THE ACTUAL
FRONT IS LOCATED FROM JUST EAST OF BOONE...SOUTH TO ABOUT
RUTHERFORDTON TO GSP. ONLY A WIND SHIFT AT THIS TIME WITH THE FRONT.
RADARS CONTINUE TO SHOW THE PREFRONTAL LINE OF NOW JUST SHRA FROM
UNION COUNTY NC...SW THROUGH SE CHESTER COUNTY SC AND THEN SOUTH OF
GREENWOOD. THIS LINE IS DRIFTING SE AND SHOULD CLEAR THE FORECAST
AREA BY MIDDAY. THEREFORE...I HAVE ADJUSTED THE POP FIELD TO FIT THE
LATEST RADAR AND TRENDS. THE HRRR IS INDICATING THAT SOME ISOLATED
SHRA COOULD DEVELOP WITH THE FRONT OVER THE EASTERN PORTION OF THE
FORECAST AREA WITH THE FRONTAL PASSAGE THIS AFTERNOON...SO HAVE
BROUGHT SOME ISOLATED POPS BACK INTO THAT AREA. OTHERWISE...EXPECT
CLEARING TO OCCUR WITH THE INCREASINGLY DOWNSLOPE WINDS. IT WILL
ALSO BE A BREEZY AFTERNOON WITH TEMPS WARMING TO A LITTLE ABOVE
AVERAGE EAST OF THE MOUNTAINS AND NEAR NORMAL MOUNTAINS. CURRENT MAX
TEMP FORECAST LOOKS ON TRACK.
1100 UTC UPDATE...WINDS WERE UPDATED TO INCLUDE THE 06Z NAM. POPS
HAVE BEEN ADJUSTED TO FIR THE TIMING OF PRECIPITATION MOVING OFF THE
BLUE RIDGE JUST AHEAD OF THE COLD FRONT.
AT 345 AM EST FRIDAY...A CLOSED UPPER LOW WILL MOVE FROM THE PLAINS
TO THE GREAT LAKES TODAY AND TONIGHT. AN ASSOCIATED COLD FRONT WILL
CROSS OUR AREA THIS MORNING...PRECEDED BY A WEAKENING LINE OF
CONVECTION. THE CURRENT TORNADO WATCH ALONG THE INTERSTATE 77
CORRIDOR WILL EXPIRE AT 400 AM...AND BASED ON RADAR TRENDS THE LINE
WILL MOVE OUT OF OUR AREA AROUND THAT TIME. CONVECTION ALONG THE
FRONT ITSELF STILL HAS LESS CHANCE OF BEING SEVERE...WITH LESS SHEAR
AND INSTABILITY. FRONTAL PASSAGE SHOULD BE AROUND DAYBREAK.
OBSERVATIONS SHOW LOW CLOUDS LINGERING FOR SOME DISTANCE BEHIND THE
FRONT...BUT CLOUDS SHOULD BREAK UP FROM THE SW BY MID MORNING.
GUSTY S WINDS WILL VEER TO WSW EAST OF THE MOUNTAINS AND NW IN THE
MOUNTAINS...REMAINING GUSTY. HIGH TEMPERATURES WILL RUNS SLIGHTLY
ABOVE NORMAL IN THE LEE OF THE MOUNTAINS WITH A WARMING DOWNSLOPE
FLOW...AND WILL BE AROUND NORMAL IN THE MOUNTAINS IN COLD ADVECTION.
WINDS WILL DECREASE TONIGHT AS THE PRESSURE GRADIENT WEAKENS...
VEERING NW IN NC...AND W IN SC. MINIMUM TEMPERATURES WILL RUN A A
FEW DEGREES BELOW NORMAL.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...SAT AND SAT NITE WILL BE QUIET WITH SLOWLY
RISING HEIGHTS AS AN UPPER LOW MOVES EASTWARD JUST NORTH OF THE
GREAT LAKES AND UPPER RIDGING MOVES IN FROM THE WEST. AT THE SFC...
WEAK HIGH PRESSURE MOVES ACROSS THE AREA AS WELL. SHUD BE DRY WX
WITH HIGHS A FEW DEGREES ABOVE NORMAL. LOWS WILL BE A LITTLE BELOW
NORMAL OVER THE MTNS AND A LITTLE ABOVE ELSEWHERE. SHORT WAVES KNOCK
DOWN THE RIDGE SUN AND MOVE ACROSS THE AREA SUN NITE. THE GFS IS A
LITTLE FASTER THAN THE OTHER GUIDANCE...BUT PRECIP MOVES TO OUR SWRN
DOORSTEP BY THE END OF THE DAY SUNDAY...THEN ACROSS THE AREA SUN
NITE. LOW LEVEL MOISTURE AND ISENTROPIC LIFT...ALONG WITH UPPER
DIVERGENCE....ARE MAXIMIZED SUN NITE WITH BEST PRECIP CHC OVER THE
SRN CWFA. WITH PRECIP HOLDING OFF...HIGHS SUN WILL BE UP TO 5
DEGREES ABOVE NORMAL. CLOUDS WILL KEEP LOWS 5 TO AS MUCH AS 10
DEGREES ABOVE NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 100 PM FRI...A UPPER LEVEL RIDGE WILL BE IN PLACE OVER THE
EAST COAST TO START THE MEDIUM RANGE 00Z TUESDAY. SURFACE HIGH
PRESSURE WILL BE OFF THE MID ATLANTIC AND NE COAST WITH A MOIST
SOUTHERLY FLOW ACROSS FLORIDA TO GA AND THE WESTERN CAROLINAS
THROUGH TUESDAY. AN UPSLOPE COMPONENT WILL HELP TO ENHANCE SMALL
POPS MAINLY OVER THE MTNS. THE RIDGE BREAKS DOWN THROUGH MID WEEK AS
WEAK LOBES OF ENERGY CROSS TN WHILE THE LARGER TROF DIGS FROM THE
ROCKIES SPREADING EAST ACROSS THE PLAINS INTO THURSDAY. LOW PRESSURE
WILL DEVELOP OVER THE INFLECTION POINT OF THE DIGGING TROF NEAR EAST
TEXAS AROUND 00Z THURSDAY AND MOVES NE. THE COLD FRONT WILL APPROACH
OUR REGION FROM THE WEST THURSDAY AND EARLY FRIDAY. CAPES ARE SHOWN
TO BE 1000 TO 1300 ALONG AND SE OF I-85 LATE THURSDAY ON THE GFS.
THE GFS IS CERTAINLY THE MORE PROGRESSIVE MODEL AS IT TAKES THE
FRONT OFF THE CAROLINA COAST BY FRIDAY EVENING. THE OLD ECMWF GETS
THE FRONT OFF THE COAST MID DAY SATURDAY. BIG DIFFERENCE IN TIMING
AND ALTHOUGH FAVORING GFS DID NOT COMPLETELY JUMP ONBOARD WITH THE
FINAL SOLUTION. TEMPERATURES WILL BE A FEW DEGREES ABOVE NORMAL
THROUGH MID WEEK THEN DROP TO NEAR OR BELOW NORMAL WITH THE PASSAGE
OF THE FRONT LATE IN THE WEEK.
&&
.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AT KCLT...VFR CIG BKN070 SHOULD SCT AROUND 18Z AS DRYER AIR
CONTINUES TO OVERSPREAD THE AREA. EXPECT SKC BY LATE AFTERNOON. WEAK
FRONT WILL MOVE EAST OF THE AREA. GUSTY SW WINDS WILL SHIFT NW AFTER
23Z AND DIMINISH.
ELSEWHERE...SCT VFR CLOUDS WILL DISSIPATE WITH SKC EXPECTED AT ALL
AIRFIELDS BY LATE AFTERNOON. GUSTY SW WINDS WILL TURN NW THIS
EVENING AS A WEAK FRONT CONTINUES TO MOVE AWAY FROM THE AREA AND
LEE TROUGH DISSIPATES. THE EXCEPTION FOR WINDS IS KAVL WHERE
WINDS WILL REMAIN NNW.
OUTLOOK...DRY HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE
WEEKEND WITH VFR CONDITIONS CONTINUING. AN UPPER DISTURBANCE WILL
APPROACH FROM THE SW SUNDAY NIGHT WHICH IS EXPECTED TO PRODUCE
SHOWERS WITH SOME RESTRICTIONS BEGINNING SUN NIGHT AND CONTINUING
THROUGH MON.
CONFIDENCE TABLE...
17-23Z 23-05Z 05-11Z 11-17Z
KCLT HIGH 99% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 100% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 100% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...DEO
NEAR TERM...LG
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...LG
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1002 AM EDT FRI APR 12 2013
.SYNOPSIS...
A STRONG COLD FRONT MOVES EAST OF THE WESTERN CAROLINAS AND
NORTHEAST GEORGIA TODAY. DRY HIGH PRESSURE WILL THEN BUILD IN FROM
THE WEST AND PERSIST THROUGH THE WEEKEND. AN UPPER LEVEL DISTURBANCE
WILL MOVE ACROSS THE AREA SUNDAY NIGHT WITH MOISTURE AND RAIN. A
MOIST SOUTHERLY FLOW THEN DEVELOPS ACROSS THE REGION THROUGH THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
AT 10AM EDT...LATEST SURFACE ANALYSIS INDICATES THAT THE ACTUAL
FRONT IS LOCATED FROM JUST EAST OF BOONE...SOUTH TO ABOUT
RUTHERFORDTON TO GSP. ONLY A WIND SHIFT AT THIS TIME WITH THE FRONT.
RADARS CONTINUE TO SHOW THE PREFRONTAL LINE OF NOW JUST SHRA FROM
UNION COUNTY NC...SW THROUGH SE CHESTER COUNTY SC AND THEN SOUTH OF
GREENWOOD. THIS LINE IS DRIFTING SE AND SHOULD CLEAR THE FORECAST
AREA BY MIDDAY. THEREFORE...I HAVE ADJUSTED THE POP FIELD TO FIT THE
LATEST RADAR AND TRENDS. THE HRRR IS INDICATING THAT SOME ISOLATED
SHRA COOULD DEVELOP WITH THE FRONT OVER THE EASTERN PORTION OF THE
FORECAST AREA WITH THE FRONTAL PASSAGE THIS AFTERNOON...SO HAVE
BROUGHT SOME ISOLATED POPS BACK INTO THAT AREA. OTHERWISE...EXPECT
CLEARING TO OCCUR WITH THE INCREASINGLY DOWNSLOPE WINDS. IT WILL
ALSO BE A BREEZY AFTERNOON WITH TEMPS WARMING TO A LITTLE ABOVE
AVERAGE EAST OF THE MOUNTAINS AND NEAR NORMAL MOUNTAINS. CURRENT MAX
TEMP FORECAST LOOKS ON TRACK.
PREVIOUS DISCUSSION:
1100 UTC UPDATE...WINDS WERE UPDATED TO INCLUDE THE 06Z NAM. POPS
HAVE BEEN ADJUSTED TO FIR THE TIMING OF PRECIPITATION MOVING OFF THE
BLUE RIDGE JUST AHEAD OF THE COLD FRONT.
AT 345 AM EST FRIDAY...A CLOSED UPPER LOW WILL MOVE FROM THE PLAINS
TO THE GREAT LAKES TODAY AND TONIGHT. AN ASSOCIATED COLD FRONT WILL
CROSS OUR AREA THIS MORNING...PRECEDED BY A WEAKENING LINE OF
CONVECTION. THE CURRENT TORNADO WATCH ALONG THE INTERSTATE 77
CORRIDOR WILL EXPIRE AT 400 AM...AND BASED ON RADAR TRENDS THE LINE
WILL MOVE OUT OF OUR AREA AROUND THAT TIME. CONVECTION ALONG THE
FRONT ITSELF STILL HAS LESS CHANCE OF BEING SEVERE...WITH LESS SHEAR
AND INSTABILITY. FRONTAL PASSAGE SHOULD BE AROUND DAYBREAK.
OBSERVATIONS SHOW LOW CLOUDS LINGERING FOR SOME DISTANCE BEHIND THE
FRONT...BUT CLOUDS SHOULD BREAK UP FROM THE SW BY MID MORNING.
GUSTY S WINDS WILL VEER TO WSW EAST OF THE MOUNTAINS AND NW IN THE
MOUNTAINS...REMAINING GUSTY. HIGH TEMPERATURES WILL RUNS SLIGHTLY
ABOVE NORMAL IN THE LEE OF THE MOUNTAINS WITH A WARMING DOWNSLOPE
FLOW...AND WILL BE AROUND NORMAL IN THE MOUNTAINS IN COLD ADVECTION.
WINDS WILL DECREASE TONIGHT AS THE PRESSURE GRADIENT WEAKENS...
VEERING NW IN NC...AND W IN SC. MINIMUM TEMPERATURES WILL RUN A A
FEW DEGREES BELOW NORMAL.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 300 AM FRIDAY...SAT AND SAT NITE WILL BE QUIET WITH SLOWLY
RISING HEIGHTS AS AN UPPER LOW MOVES EASTWARD JUST NORTH OF THE
GREAT LAKES AND UPPER RIDGING MOVES IN FROM THE WEST. AT THE SFC...
WEAK HIGH PRESSURE MOVES ACROSS THE AREA AS WELL. SHUD BE DRY WX
WITH HIGHS A FEW DEGREES ABOVE NORMAL. LOWS WILL BE A LITTLE BELOW
NORMAL OVER THE MTNS AND A LITTLE ABOVE ELSEWHERE. SHORT WAVES KNOCK
DOWN THE RIDGE SUN AND MOVE ACROSS THE AREA SUN NITE. THE GFS IS A
LITTLE FASTER THAN THE OTHER GUIDANCE...BUT PRECIP MOVES TO OUR SWRN
DOORSTEP BY THE END OF THE DAY SUNDAY...THEN ACROSS THE AREA SUN
NITE. LOW LEVEL MOISTURE AND ISENTROPIC LIFT...ALONG WITH UPPER
DIVERGENCE....ARE MAXIMIZED SUN NITE WITH BEST PRECIP CHC OVER THE
SRN CWFA. WITH PRECIP HOLDING OFF...HIGHS SUN WILL BE UP TO 5
DEGREES ABOVE NORMAL. CLOUDS WILL KEEP LOWS 5 TO AS MUCH AS 10
DEGREES ABOVE NORMAL.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 325 AM FRI...SHORT WAVES SLIDE EAST OF THE AREA MONDAY WITH
RIDGING RETURNING MON NITE. PRECIP TAPERS OFF MONDAY WITH ONLY SOME
LINGERING SHRA ACROSS THE NC MTNS MON NITE. HOWEVER...THERE WILL BE
CONTINUED CLOUDINESS AS LOW LEVELS REMAIN MOIST. HIGHS MONDAY WILL
BE A COUPLE OF DEGREES ABOVE NORMAL WITH LOWS MONDAY NITE AROUND 10
DEGREES ABOVE NORMAL.
THE UPPER RIDGE IS FORECAST TO LINGER THROUGH MIDWEEK. THE ECMWF AND
GFS KEEP A FRONTAL SYSTEM NORTH OF THE AREA TUE AND WED WITH
GENERALLY DIURNAL CONVECTION IN THE MOIST SLY FLOW. THEREFORE...HAVE
SCATTERED AFTERNOON CONVECTION CONFINED TO THE MOUNTAINS. ON THU...A
COLD FRONT WILL APPROACH FROM THE WEST. THE GFS IS INITIALLY FASTER
BRINGING THE FRONT TO E TN BY THE END OF THE DAY THU...BUT THEN
SLOWS CLOSER TO THE ECMWF THU NITE. WPC LIKES THE SLIGHTLY SLOWER
ECMWF SOLN...SO FOLLOWED THEIR GUIDANCE. THIS RAMPS UP CHANCE POPS
ACROSS THE AREA ON THU. TEMPERATURES WARM TO WELL ABOVE NORMAL ON
TUE/WED AND THEN BACK TO NEAR NORMAL FOR THU DUE TO CLOUDS AND
PRECIP.
&&
.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AT KCLT...IFR CIG...AND POSSIBLE VSBY RESTRICTIONS IN SHOWERS...ARE
EXPECTED AS A COLD FRONT MOVES THROUGH EARLY THIS MORNING. BASED ON
OBSERVATIONS UPSTREAM AND BEHIND THE FRONT...MVFR CIG RESTRICTIONS
MAY PERSIS AFTER FRONTAL PASSAGE...BUT SHOULD LIFT BY MID MORNING AS
DRIER AIR ARRIVES. S WINDS WILL VEER TO WSW...REMAINING GUSTY. WINDS
BECOME LIGHT NW TONIGHT. GUIDANCE DOW NO SUPPORT RESTRICTIONS EARLY
SATURDAY MORNING AS THE NEW AIR MASS IS TOO DRY.
ELSEWHERE...IFR OT MVFR CIGS WILL PERSIST AHEAD OF AND BEHIND A COLD
FRONT CROSSING THE AREA EARLY THIS MORNING. MVFR VSBY RESTRICTIONS
ARE POSSIBLE IN SHOWERS AHEAD OF THE FRONT. DRIER AIR MAY TAKE A FEW
HOURS TO ARRIVE BEHIND THE FRONT BASED ON TRENDS UPSTREAM...BUT BY
MID MORNING...VFR IS EXPECTED. S WINDS WILL VEER TO WSW IN THE
FOOTHILLS TODAY...AND NW IN THE MOUNTAINS...BECOMING RATHER GUSTY.
WINDS WILL VEER TO THE NW IN NC TONIGHT...REMAINING WSW IN SC...AND
DIMINISHING AT ALL SITE. MODEL GUIDANCE MAINTAINS VFR THROUGH EARLY
SATURDAY MORNING AS THE NEWLY ARRIVED DRIER AIR MASS WILL NOT
SUPPORT FOG.
OUTLOOK...DRY HIGH PRESSURE WILL BUILD INTO THE REGION THROUGH THE
WEEKEND. MOISTURE WILL APPROACH FORM THE SOUTH EARLY NEXT WEEK...BUT
CONFIDENCE IS LIMITED ON THE POSSIBILITY OF RESTRICTIONS.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 93% HIGH 100% HIGH 100% HIGH 100%
KGSP HIGH 96% HIGH 100% HIGH 100% HIGH 100%
KAVL HIGH 95% HIGH 100% HIGH 100% HIGH 100%
KHKY HIGH 93% HIGH 100% HIGH 100% HIGH 100%
KGMU HIGH 99% HIGH 100% HIGH 100% HIGH 100%
KAND HIGH 96% HIGH 100% HIGH 100% HIGH 100%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...RWH
NEAR TERM...LG
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...JAT