Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/10/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
752 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 AIRMASS 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 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 320 PM MDT TUE APR 9 2013
ANOTHER ROUND OF SNOW WILL LIFT TO THE NORTH ACROSS THE I-25
CORRIDOR LATE THIS AFTERNOON THROUGH EARLY THIS EVENING. THIS
PRODUCE MVFR TO IFR CONDITIONS AT THE KCOS AND KPUB TAF SITES
THROUGH THE LATE AFTERNOON AND EVENING...WITH CIGS RISING INTO THE
MVFR CATEGORY AS DRYING MOVES IN BEHIND. GUSTY NORTH WINDS FROM 20
TO 35 KTS WILL GRADUALLY DECREASE THROUGH THE EVENING...AND ALTHOUGH
THERE WILL STILL BE A PERIOD OF FALLING/BLOWING SNOW WITH THIS
BAND...THINK THAT ANY ADDITIONAL ACCUMULATIONS WILL REMAIN AROUND AN
INCH OR LESS FOR BOTH TERMINALS. SNOW SHOULD COME TO AN END FOR BOTH
TAF SITES BY 03Z...WITH MVFR CIGS PERSISTING THROUGH THE NIGHT. KALS
WILL SEE THE BEST CHANCE FOR SNOW FROM NOW THROUGH 03Z...WITH
PERIODIC IFR CIGS/VIS IN SNSH. MVFR CIGS WILL PERSIST THROUGH THE
NIGHT.
VFR TO MVFR CIGS WILL CONTINUE ACROSS THE REGION THROUGH
WEDNESDAY...WITH INSTABILITY SNOW SHOWERS ACROSS THE MOUNTAINS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM MDT THIS EVENING FOR
COZ061>063-065-067-072-073-076>080.
WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ058-060-
066-068.
&&
$$
UPDATE...28
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...KT
AREA FORECAST DISCUSSION
NWS PUEBLO CO
601 PM MDT TUE APR 9 2013
.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 AIRMASS 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 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 320 PM MDT TUE APR 9 2013
ANOTHER ROUND OF SNOW WILL LIFT TO THE NORTH ACROSS THE I-25
CORRIDOR LATE THIS AFTERNOON THROUGH EARLY THIS EVENING. THIS
PRODUCE MVFR TO IFR CONDITIONS AT THE KCOS AND KPUB TAF SITES
THROUGH THE LATE AFTERNOON AND EVENING...WITH CIGS RISING INTO THE
MVFR CATEGORY AS DRYING MOVES IN BEHIND. GUSTY NORTH WINDS FROM 20
TO 35 KTS WILL GRADUALLY DECREASE THROUGH THE EVENING...AND ALTHOUGH
THERE WILL STILL BE A PERIOD OF FALLING/BLOWING SNOW WITH THIS
BAND...THINK THAT ANY ADDITIONAL ACCUMULATIONS WILL REMAIN AROUND AN
INCH OR LESS FOR BOTH TERMINALS. SNOW SHOULD COME TO AN END FOR BOTH
TAF SITES BY 03Z...WITH MVFR CIGS PERSISTING THROUGH THE NIGHT. KALS
WILL SEE THE BEST CHANCE FOR SNOW FROM NOW THROUGH 03Z...WITH
PERIODIC IFR CIGS/VIS IN SNSH. MVFR CIGS WILL PERSIST THROUGH THE
NIGHT.
VFR TO MVFR CIGS WILL CONTINUE ACROSS THE REGION THROUGH
WEDNESDAY...WITH INSTABILITY SNOW SHOWERS ACROSS THE MOUNTAINS.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 9 PM MDT THIS EVENING FOR
COZ061>063-065-067-072-073-076>080-089-093>096.
WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ058-060-
066-068.
&&
$$
UPDATE...28
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...KT
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1053 AM MDT MON APR 8 2013
.UPDATE...VERY COMPLEX WEATHER SCENARIO FOR THE FORECAST AREA
STILL MAKING FOR A DIFFICULT FORECAST. LATEST WATER VAPOR LOOP
SHOWS CONSIDERABLE DIGGING STILL OCCURRING AND 12Z RAOBS/RUC
ANALYSIS WOULD SUGGEST A 150 KT JET DIVING DOWN THE BACK SIDE OF
THIS TROUGH SO FURTHER DIGGING LIKELY. THE 12Z MODEL RUNS HAVE
TRENDED BACK A LITTLE FARTHER SOUTH AND THIS SEEMS GOOD
CONSIDERING THE WATER VAPOR IMAGERY. AT THE SAME TIME...COLD FRONT
IS ALREADY BARRELING SOUTHWARD THROUGH EASTERN WYOMING AND SHOULD
REACH DENVER BY/SHORTLY BEFORE 00Z GIVEN STRONG PRESSURE RISES
BEHIND THE FRONT...AND ONLY BECAUSE OF SOME SLOWING DUE TO DAYTIME
HEATING/MIXING AHEAD OF THE FRONT OTHERWISE IT WOULD BE HERE
SOONER. LATEST 12Z NAM SHOWS A STRONG BARRIER JET FORMING THIS
EVENING AS COLD AIR PLUNGES SOUTHWARD ALONG THE FRONT RANGE. THIS
COULD LEAD TO A PERIOD OF CONVECTIVE AND HEAVY SNOWFALL AS RAIN
QUICKLY CHANGES OVER TO SNOW...WITH A COUPLE HOURS OF NEAR
BLIZZARD CONDITIONS POSSIBLE ALL DEPENDING ON WHETHER COLD AIR
ARRIVAL COINCIDES WITH CONVECTION.
WITH REGARD TO SEVERE THREAT...LITTLE CHANGE THERE TOO WITH
POSSIBLE LARGE HAIL AND TORNADO THREAT MAINLY ALONG/EAST OF A LINE
FROM FORT MORGAN TO LIMON. HIGHEST PROBABILITY WOULD LIKELY SHIFT
TOWARD AKRON AND LIMON WITH FASTER ARRIVAL OF FRONT. STILL SOME
CIRRUS TO OVERCOME BUT TEMPS ALREADY IN THE LOWER 60S AND IF WE
REACH 70F THEN STORMS WILL POP.
FOR LATER TONIGHT...THE SNOW COULD VERY WELL DECREASE ESPECIALLY
OVER THE SOUTHERN HALF OF THE FORECAST AREA OVERNIGHT AS A DRY
SLOT WORKS NORTHWARD...BUT SHOULD SPREAD BACK SOUTH/SOUTHEAST OVER
NORTHEAST COLORADO TUESDAY MORNING AS UPPER LOW TRACKS TOWARD THE
FOUR CORNERS. WATCHES HAVE BEEN UPGRADED TO WARNINGS IN AREAS OF
HIGHEST CONFIDENCE WHILE WATCHES WILL CONTINUE OVER THE FAR
EASTERN PLAINS DUE TO HIGHER POTENTIAL FOR DRY SLOT PERSISTING
THERE. WILL GO WITH BLIZZARD WARNINGS FOR POINTS JUST
EAST/SOUTHEAST OF DENVER WHERE STRONGER WINDS WILL BE MORE
PERSISTENT.
&&
.AVIATION...SOUTHERLY WINDS WERE A LITTLE DELAYED AT KDEN.
OTHERWISE TAFS WILL BE PRETTY MUCH UNCHANGED. WILL SUGGEST HEAVIER
SNOW POTENTIAL FOR A COUPLE HOURS 03Z-06Z THIS EVENING...THEN SOME
DECREASE LATE...AND INCREASE AGAIN BY TUESDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 408 AM MDT MON APR 8 2013/
SHORT TERM...FOR TODAY AND TONIGHT...A COMPLEX WEATHER PATTERN IS
SETTING UP ACROSS THE REGION. PACIFIC STORM IS DIGGING SOUTHEAST
ACROSS NORTHERN CALIFORNIA AT THIS TIME. LATEST MODELS HAVE BEEN
SHOWING A SLIGHT SHIFT NORTH IN THE STORM TRACK. BY 12 TUESDAY
MORNING...THE UPPER LEVEL LOW WILL BE CENTER JUST WEST OF THE FOUR
CORNERS WITH THE SURFACE LOW NEAR THE OKLAHOMA PAN HANDLE.
STILL A GOOD AMOUNT OF UNCERTAINTY ON THE PLACEMENT OF THE DRY LINE
AND WHEN THE COLD FRONT WILL PUSH THROUGH THE AREA. STILL APPEARS
THE DRY LINE WILL BE ROUGHLY ALONG A LINE FROM FORT MORGAN TO LIMON.
HOWEVER...THE LATEST RAP HAS IT NEAR DENVER EARLY THIS EVENING
BEFORE THE COLD FRONT PUSHES THROUGH. BEST CHANCE FOR THUNDERSTORMS
WILL OCCUR EAST OF WHERE THE DRY LINE SETS UP. DUE TO STRONG
SHEAR...SUPERCELLS WILL BE POSSIBLE WITH LARGE HAIL. SINCE LOW LEVEL
SHEAR WILL BE STRONG...TORNADOES WILL ALSO BE POSSIBLE WITH ANY
STRONG STORM THAT DEVELOPS.
MODELS ARE COMING INTO BETTER AGREEMENT OVER THE LAST HOUR IN
SHOWING THE COLD FRONT ENTERING COLORADO LATE THIS AFTERNOON AND
PUSHING THROUGH THE DENVER AREA AROUND 00Z. NORTH TO NORTHEAST
UPSLOPE WINDS BEHIND THE FRONT COMBINED WITH A STRONG DIFFLUENT FLOW
ALOFT WILL GENERATE LIFT THROUGH OUT THE AIRMASS. PRECIPITATION WILL
START OFF AS RAIN AND CHANGE OVER TO SNOW AS COLD AIR MOVES INTO THE
AREA. FOR THE DENVER AREA...WOULD EXPECT THE CHANGE OVER TO SNOW
AROUND MID TO LATE EVENING.
THE AREA IS ON THE EDGE OF THE HEAVIER SNOW. IF THIS SYSTEM KEEPS
TRENDING NORTH...THE HEAVY SNOW MAY END UP JUST TO OUR NORTH. ALSO
WHEN THE RAIN CHANGES TO SNOW WILL PLAY A BIG ROLE ON HOW MUCH SNOW
ACCUMULATES. THEREFORE WILL CONTINUE WITH THE WINTER STORM WATCH AT
THIS TIME AND NOT UPGRADE TO ANY WARNINGS.
DID INCREASE TEMPERATURES INTO THE MID TO UPPER 60S FOR MOST OF
NORTHEAST COLORADO. AIRMASS WILL LIKELY BE WARM ENOUGH TO SUPPORT
LOWER 70S...BUT EXPECT THE MOSTLY CLOUDY SKIES TO TAKE OFF A FEW
DEGREES FROM REACHING OUR FULL POTENTIAL.
LONG TERM...AS MENTIONED A FEW DAYS AGO IT NEVER FAILS THAT
SOMETHING WILL MANY TIMES MESS UP A DECENT STORM AND IT APPEARS
THIS TIME WILL BE NO DIFFERENT. ALTHOUGH THERE IS GOOD AGREEMENT
THAT A CLOSED UPPER LEVEL LOW WILL BE NR THE FOUR CORNERS BY
12Z...BY TUE EVENING THE MODELS PRETTY MUCH SPLIT THE SYSTEM WITH
THE MAIN PIECE OF ENERGY LIFTING NE INTO EITHER SERN WY OR WRN
NEBRASKA. THE ECMWF TRACKS THIS FEATURE WEST OF NERN CO WHILE THE
NAM AND GFS HAVE IT MOVING ACROSS NERN CO ON TUE. THERE IS STILL
DECENT UPSLOPE TUE MORNING WITH FAVORABLE QG ASCENT SO STILL CAN
NOT RULE OUT SOME HEAVIER SNOW THRU MID TO LATE MORNING IN AND NR
THE FOOTHILLS AND POSSIBLY OVER THE PALMER DIVIDE. MEANWHILE OVER
THE PLAINS OF NERN CO A POTENTIAL DRY SLOT MAY DEVELOP WHICH WOULD
LIMIT HEAVY SNOW POTENTIAL EAST OF A STERLING TO LIMON LINE THRU
THE AFTN HOURS. FOR NOW WILL LEAVE WATCHES AS IS AND LET THE DAY
SHIFT SEE IF THE MODELS CAN COME TO A CONSENSUS ON WHERE BEST
HEAVY SNOWFALL POTENTIAL MAY OCCUR. WINDS WILL BE GUSTY ON TUE SO
STILL EXPECT AREAS OF BLOWING SNOW. HIGHS WILL BE WELL BLO NORMAL
WITH READINGS NOT GETTING OUT OF THE 20S.
BY TUE NIGHT INTO WED THE UPPER LEVEL LOW IS FCST TO STALL OVER
WRN NEBRASKA. THE ECMWF AND GFS SHOW DRIER AIR SPREADING OVER NERN
CO ALTHOUGH THERE IS STILL SOME MOISTURE IN THE MTNS WHICH MAY
LEAD TO A CHC OF LIGHT OROGRAPHIC SNOWS. MEANWHILE GUSTY NLY
WINDS WILL STILL OCCUR OVER THE PLAINS OF NERN CO THRU THE AFTN.
HIGHS ON WED DUE TO LINGERING COLD TEMPS IN THE 850-700 MB LAYER
WILL ONLY BE IN THE 30S OVER NERN CO.
FOR THU THE UPPER LEVEL WILL MOVE EASTWARD WITH NWLY FLOW ALOFT
OVER NRN CO. A DISTURBANCE IN THIS FLOW WILL MOVE ACROSS NRN CO
LATE THU AFTN OR EVENING. CROSS- SECTIONS SHOW MOISTURE
INCREASING THE MTNS WITH DECENT LAPSE RATES SO MAY SEE A GOOD CHC
OF SNOW IN THE AFTN AND EVENING. OVER NERN CO ANOTHER WK FNT IS
FCST TO MOVE ACROSS THE AREA BY EVENING BRIEFLY ENHANCING UPSLOPE
FLOW. THIS IS THE DISTURBANCE MOVES ACROSS ALONG WITH A DECENT
UPPER LEVEL JET THIS COULD LEAD TO A CHC OF PCPN LATE THU AFTN
INTO THU EVENING. WILL KEEP HIGHS ON THU WILL IN THE MID TO UPPER 40S
ACROSS THE PLAINS.
BY FRI THE FLOW ALOFT WILL REMAIN NWLY WITH QUITE A BIT OF
MOISTURE EMBEDDED IN THE FLOW. THE ECMWF AND GFS SHOW ANOTHER
POTENTIAL DISTURBANCE TRACKING ACROSS THE AREA FRI AFTN INTO FRI
EVENING WITH ANOTHER WEAK SURGE MOVING ACROSS NERN CO. THUS SHOULD
SEE ANOTHER CHC OF SNOW IN THE MTNS WITH AT LEAST A SLIGHT CHC OF
PCPN AT LOWER ELEVATIONS. AS FOR HIGHS WILL HAVE READINGS IN THE
UPPER 40S TO LOWER 50S OVER NERN CO.
FOR THE WEEKEND RIGHT NOW THE FLOW ALOFT IS SUPPOSED TO BECOME
MORE ZONAL WHICH WOULD LEAD TO WARMER TEMPERATURES AND DRIER
CONDITIONS.
AVIATION...SOUTH TO SOUTHEAST WINDS WILL PREVAIL THROUGH THE DAY
UNTIL A COLD FRONT PUSHES THROUGH AROUND 23-00Z. WINDS WILL TURN
NORTHERLY BEHIND IT. WILL BE A CHANCE FOR THUNDERSTORMS AFTER
21Z...BUT THE BEST CHANCE WILL BE OVER FAR EASTERN COLORADO. RAIN
WILL DEVELOP AFTER 00Z TONIGHT AND CHANGE TO SNOW AROUND 04-05Z.
SNOW WILL BE HEAVY AT TIMES. VISIBILITY WILL BE REDUCED TO QUARTER
MILE OR LESS AT TIMES DUE TO SNOW AND BLOWING SNOW. THE HEAVIEST
SNOW IS EXPECTED TO FALL FROM 06-18Z TUESDAY. SNOWFALL TOTALS AT THE
DENVER AIRPORTS ARE EXPECTED TO RANGE FROM 6 TO 12 INCHES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY EVENING FOR
COZ046-048>051.
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MDT TUESDAY
FOR COZ033>036.
WINTER STORM WARNING FROM 9 PM THIS EVENING TO 6 PM MDT TUESDAY
FOR COZ038>040-042>044.
BLIZZARD WARNING FROM MIDNIGHT TONIGHT TO 6 PM MDT TUESDAY FOR
COZ041-045.
&&
$$
SHORT TERM...BARJENBRUCH
LONG TERM....RPK
AVIATION...BARJENBRUCH
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
408 AM MDT MON APR 8 2013
.SHORT TERM...FOR TODAY AND TONIGHT...A COMPLEX WEATHER PATTERN IS
SETTING UP ACROSS THE REGION. PACIFIC STORM IS DIGGING SOUTHEAST
ACROSS NORTHERN CALIFORNIA AT THIS TIME. LATEST MODELS HAVE BEEN
SHOWING A SLIGHT SHIFT NORTH IN THE STORM TRACK. BY 12 TUESDAY
MORNING...THE UPPER LEVEL LOW WILL BE CENTER JUST WEST OF THE FOUR
CORNERS WITH THE SURFACE LOW NEAR THE OKLAHOMA PAN HANDLE.
STILL A GOOD AMOUNT OF UNCERTAINTY ON THE PLACEMENT OF THE DRY LINE
AND WHEN THE COLD FRONT WILL PUSH THROUGH THE AREA. STILL APPEARS
THE DRY LINE WILL BE ROUGHLY ALONG A LINE FROM FORT MORGAN TO LIMON.
HOWEVER...THE LATEST RAP HAS IT NEAR DENVER EARLY THIS EVENING
BEFORE THE COLD FRONT PUSHES THROUGH. BEST CHANCE FOR THUNDERSTORMS
WILL OCCUR EAST OF WHERE THE DRY LINE SETS UP. DUE TO STRONG
SHEAR...SUPERCELLS WILL BE POSSIBLE WITH LARGE HAIL. SINCE LOW LEVEL
SHEAR WILL BE STRONG...TORNADOES WILL ALSO BE POSSIBLE WITH ANY
STRONG STORM THAT DEVELOPS.
MODELS ARE COMING INTO BETTER AGREEMENT OVER THE LAST HOUR IN
SHOWING THE COLD FRONT ENTERING COLORADO LATE THIS AFTERNOON AND
PUSHING THROUGH THE DENVER AREA AROUND 00Z. NORTH TO NORTHEAST
UPSLOPE WINDS BEHIND THE FRONT COMBINED WITH A STRONG DIFFLUENT FLOW
ALOFT WILL GENERATE LIFT THROUGH OUT THE AIRMASS. PRECIPITATION WILL
START OFF AS RAIN AND CHANGE OVER TO SNOW AS COLD AIR MOVES INTO THE
AREA. FOR THE DENVER AREA...WOULD EXPECT THE CHANGE OVER TO SNOW
AROUND MID TO LATE EVENING.
THE AREA IS ON THE EDGE OF THE HEAVIER SNOW. IF THIS SYSTEM KEEPS
TRENDING NORTH...THE HEAVY SNOW MAY END UP JUST TO OUR NORTH. ALSO
WHEN THE RAIN CHANGES TO SNOW WILL PLAY A BIG ROLE ON HOW MUCH SNOW
ACCUMULATES. THEREFORE WILL CONTINUE WITH THE WINTER STORM WATCH AT
THIS TIME AND NOT UPGRADE TO ANY WARNINGS.
DID INCREASE TEMPERATURES INTO THE MID TO UPPER 60S FOR MOST OF
NORTHEAST COLORADO. AIRMASS WILL LIKELY BE WARM ENOUGH TO SUPPORT
LOWER 70S...BUT EXPECT THE MOSTLY CLOUDY SKIES TO TAKE OFF A FEW
DEGREES FROM REACHING OUR FULL POTENTIAL.
.LONG TERM...AS MENTIONED A FEW DAYS AGO IT NEVER FAILS THAT
SOMETHING WILL MANY TIMES MESS UP A DECENT STORM AND IT APPEARS
THIS TIME WILL BE NO DIFFERENT. ALTHOUGH THERE IS GOOD AGREEMENT
THAT A CLOSED UPPER LEVEL LOW WILL BE NR THE FOUR CORNERS BY
12Z...BY TUE EVENING THE MODELS PRETTY MUCH SPLIT THE SYSTEM WITH
THE MAIN PIECE OF ENERGY LIFTING NE INTO EITHER SERN WY OR WRN
NEBRASKA. THE ECMWF TRACKS THIS FEATURE WEST OF NERN CO WHILE THE
NAM AND GFS HAVE IT MOVING ACROSS NERN CO ON TUE. THERE IS STILL
DECENT UPSLOPE TUE MORNING WITH FAVORABLE QG ASCENT SO STILL CAN
NOT RULE OUT SOME HEAVIER SNOW THRU MID TO LATE MORNING IN AND NR
THE FOOTHILLS AND POSSIBLY OVER THE PALMER DIVIDE. MEANWHILE OVER
THE PLAINS OF NERN CO A POTENTIAL DRY SLOT MAY DEVELOP WHICH WOULD
LIMIT HEAVY SNOW POTENTIAL EAST OF A STERLING TO LIMON LINE THRU
THE AFTN HOURS. FOR NOW WILL LEAVE WATCHES AS IS AND LET THE DAY
SHIFT SEE IF THE MODELS CAN COME TO A CONSENSUS ON WHERE BEST
HEAVY SNOWFALL POTENTIAL MAY OCCUR. WINDS WILL BE GUSTY ON TUE SO
STILL EXPECT AREAS OF BLOWING SNOW. HIGHS WILL BE WELL BLO NORMAL
WITH READINGS NOT GETTING OUT OF THE 20S.
BY TUE NIGHT INTO WED THE UPPER LEVEL LOW IS FCST TO STALL OVER
WRN NEBRASKA. THE ECMWF AND GFS SHOW DRIER AIR SPREADING OVER NERN
CO ALTHOUGH THERE IS STILL SOME MOISTURE IN THE MTNS WHICH MAY
LEAD TO A CHC OF LIGHT OROGRAPHIC SNOWS. MEANWHILE GUSTY NLY
WINDS WILL STILL OCCUR OVER THE PLAINS OF NERN CO THRU THE AFTN.
HIGHS ON WED DUE TO LINGERING COLD TEMPS IN THE 850-700 MB LAYER
WILL ONLY BE IN THE 30S OVER NERN CO.
FOR THU THE UPPER LEVEL WILL MOVE EASTWARD WITH NWLY FLOW ALOFT
OVER NRN CO. A DISTURBANCE IN THIS FLOW WILL MOVE ACROSS NRN CO
LATE THU AFTN OR EVENING. CROSS- SECTIONS SHOW MOISTURE
INCREASING THE MTNS WITH DECENT LAPSE RATES SO MAY SEE A GOOD CHC
OF SNOW IN THE AFTN AND EVENING. OVER NERN CO ANOTHER WK FNT IS
FCST TO MOVE ACROSS THE AREA BY EVENING BRIEFLY ENHANCING UPSLOPE
FLOW. THIS IS THE DISTURBANCE MOVES ACROSS ALONG WITH A DECENT
UPPER LEVEL JET THIS COULD LEAD TO A CHC OF PCPN LATE THU AFTN
INTO THU EVENING. WILL KEEP HIGHS ON THU WILL IN THE MID TO UPPER 40S
ACROSS THE PLAINS.
BY FRI THE FLOW ALOFT WILL REMAIN NWLY WITH QUITE A BIT OF
MOISTURE EMBEDDED IN THE FLOW. THE ECMWF AND GFS SHOW ANOTHER
POTENTIAL DISTURBANCE TRACKING ACROSS THE AREA FRI AFTN INTO FRI
EVENING WITH ANOTHER WEAK SURGE MOVING ACROSS NERN CO. THUS SHOULD
SEE ANOTHER CHC OF SNOW IN THE MTNS WITH AT LEAST A SLIGHT CHC OF
PCPN AT LOWER ELEVATIONS. AS FOR HIGHS WILL HAVE READINGS IN THE
UPPER 40S TO LOWER 50S OVER NERN CO.
FOR THE WEEKEND RIGHT NOW THE FLOW ALOFT IS SUPPOSED TO BECOME
MORE ZONAL WHICH WOULD LEAD TO WARMER TEMPERATURES AND DRIER
CONDITIONS.
&&
.AVIATION...SOUTH TO SOUTHEAST WINDS WILL PREVAIL THROUGH THE DAY
UNTIL A COLD FRONT PUSHES THROUGH AROUND 23-00Z. WINDS WILL TURN
NORTHERLY BEHIND IT. WILL BE A CHANCE FOR THUNDERSTORMS AFTER
21Z...BUT THE BEST CHANCE WILL BE OVER FAR EASTERN COLORADO. RAIN
WILL DEVELOP AFTER 00Z TONIGHT AND CHANGE TO SNOW AROUND 04-05Z.
SNOW WILL BE HEAVY AT TIMES. VISIBILITY WILL BE REDUCED TO QUARTER
MILE OR LESS AT TIMES DUE TO SNOW AND BLOWING SNOW. THE HEAVIEST
SNOW IS EXPECTED TO FALL FROM 06-18Z TUESDAY. SNOWFALL TOTALS AT THE
DENVER AIRPORTS ARE EXPECTED TO RANGE FROM 6 TO 12 INCHES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ042-044>046-048>051.
WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
FOR COZ033>036.
WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
FOR COZ038>041-043.
&&
$$
SHORT TERM...MEIER
LONG TERM....RPK
AVIATION...MEIER
AREA FORECAST DISCUSSION
NWS TAUNTON MA
940 PM EDT TUE APR 9 2013
.SYNOPSIS...
A FRONT WILL REMAIN JUST SOUTH OF NEW ENGLAND OVERNIGHT AND WILL
BRING A ROUND OF RAIN SHOWERS TO THE REGION. DRY WEATHER FOLLOWS
FOR MOST OF THE DAY WED WITH MORE SHOWERS EXPECTED WED NIGHT INTO
EARLY THU MORNING. COOLER TEMPS WILL FOLLOW THU AND FRI AS ANOTHER
LOW MOVES ACROSS THE REGION...AND BRINGS A PERIOD OF HEAVY RAIN
FRI AFTERNOON AND EVENING. MAINLY DRY AND SEASONABLY COOL WEATHER
IS EXPECTED THIS WEEKEND INTO EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
940 PM UPDATE...
SURFACE ANALYSIS SHOWS FRONTAL BOUNDARY FROM LAKE ERIE ACROSS
NY/PA BORDER TO EASTERN LONG ISLAND AND JUST SOUTH OF NANTUCKET.
FRONT SHOULD DROP A LITTLE FARTHER S IN OUR AREA OVERNIGHT AS
COOLER AIR WINS OUT ON E/NE WINDS...AND FRONT LIFTS FARTHER N
ACROSS EASTERN GREAT LAKES. 13KM RAP CAPTURES THIS TREND NICELY.
REGIONAL RADAR MOSAIC SHOWS AREA OF SHOWERS PUSHING E ACROSS MUCH
OF UPSTATE NY ON COOL SIDE OF FRONT...ESPECIALLY N OF THRUWAY.
THIS SHOULD CONTINUE TO BE TREND OVERNIGHT AS MOST OF SHOWERS FALL
ACROSS NORTHERN MA AND SW NH WHICH IS IN LINE WITH GOING FORECAST.
ACTIVITY SHOULD BE MORE SCATTERED IN NATURE AND LIGHT ROUGHLY
ALONG AND S OF MASS PIKE.
ALTHOUGH WE ARE SEEING SOME LIGHTNING STRIKES AND COOLING CLOUD
TOPS OVER NIAGARA FRONTIER...RAP KEEPS MUCH OF ELEVATED
INSTABILITY TO OUR S OVERNIGHT...ALTHOUGH IT DOES GRAZE S COAST
AND SHOWS FAIRLY TIGHT THETA-E GRADIENT IN THAT AREA AS WELL. SO
AN ISOLATED RUMBLE OF THUNDER IS POSSIBLE ACROSS CT/RI/SE MA BUT
PROSPECTS SEEM VERY LOW.
FORECAST LOWS ARE ON TRACK...IN 40S TO NEAR 50.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
WEDNESDAY...
THE BULK OF THE SHOWERS WILL HAVE ALREADY EXITED MOST OF THE REGION
BY EARLY IN THE MORNING. CAN/T RULE OUT A SPOT SHOWER OR TWO DURING
THE DAY...BUT GENERALLY A DRY DAY IS EXPECTED.
LOW CONFIDENCE ON SKY CONDITIONS...BUT FEEL THAT MUCH OF THE REGION
SHOULD EVENTUALLY SEE A PERIOD OF PARTIAL SUNSHINE. HIGH
TEMPERATURES ARE ALSO UNCERTAIN...GIVEN THE
EXACT PLACEMENT OF THE BOUNDARY AND SKY COVER. WE ARE CONFIDENT
THAT THE COOLEST READINGS WILL BE FOUND IN OUR NORTHEAST
ZONES...WITH THE MILDEST TEMPS IN OUR SOUTHWEST ZONES. WEAK
GRADIENT THOUGH WILL CERTAINLY ALLOW FOR SEA BREEZES...SO TEMPS
ALONG THE IMMEDIATE COAST SHOULD BE IN THE 50S FOR MUCH OF THE DAY.
THE REST OF THE REGION SHOULD STILL SEE HIGHS RECOVER INTO THE
60S WITH EVEN SOME LOWER 70S POSSIBLE ACROSS NORTHERN CT. THERE
REALLY IS NOT A STRONG PUSH OF COOL AIR...SO OTHER THAN ALONG THE
IMMEDIATE COAST IT STILL SHOULD BE A VERY NICE DAY ALTHOUGH NOT AS
WARM AS TODAY.
WEDNESDAY NIGHT...
ANOTHER WAVE OF LOW PRESSURE WILL MOVE ACROSS THE REGION ON A SLOWLY
SAGGING SOUTHWARD FRONT. THIS SHOULD BRING ANOTHER ROUND OF RAIN
SHOWERS TO THE REGION WED NIGHT. GIVEN THAT THE FRONT WILL BE
SAGGING SOUTH OF OUR REGION...THERE WILL BE BETTER LIFT OVER THE
BOUNDARY AND RAINFALL AMOUNTS SHOULD BE HIGHER THAN WHAT WE SEE
TONIGHT. THERE MAY BE A PERIOD OF BRIEF HEAVY RAIN SHOWERS. HAVE
ENOUGH CONFIDENCE TO RUN WITH A PERIOD OF CATEGORICAL POPS TO COVER
THESE SHOWERS. LOW TEMPERATURES WILL FALL INTO THE LOWER TO MIDDLE
40S IN MOST LOCATIONS...ALTHOUGH NORTHERN CT SHOULD REMAIN MILDER IN
THE MIDDLE TO UPPER 40S. AGAIN...CAN/T RULE OUT AN ISOLATED
THUNDERSTORM NEAR THE SOUTH COAST BUT INDICES ARE TOO MARGINAL TO
CARRY IN THE FORECAST AT THIS TIME.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
HIGHLIGHTS...
* BELOW AVG TEMPS ON THURSDAY
* STRONG COLD FRONT WILL MOVE THROUGH ON FRIDAY
* TEMPS INCREASING THIS WEEKEND THROUGH THE FIRST HALF OF THE WEEK
CONFIDENCE LEVEL/MODEL GUIDANCE...
12Z MODELS SUITE IS IN GENERAL AGREEMENT WITH OVERALL TRENDS IN THE
SYSTEMS. HOWEVER WHERE THE EXACT PLACEMENT OF EACH SYSTEM WILL SET
UP REMAINS UNCERTAIN. OVERALL HAVE MODERATE CONFIDENCE IN FORECAST
ESPECIALLY FOR THURSDAY AND INTO EARLY NEXT WEEK. HAVE HIGH
CONFIDENCE IN FORECAST FOR FRIDAY IN TERMS OF LOW PRESSURE SYSTEM
MOVING ACROSS THE AREA.
MODELS ARE IN GOOD AGREEMENT IN PUSHING BOUNDARY ON THURSDAY ACROSS
SOUTHERN ZONES. HOWEVER IT APPEARS THAT THE GFS IS SIGNIFICANTLY
WARMER THAN THE EC AND THE NAM...WHICH IS THE COLDEST SOLUTION. THE
GFS IS ALSO FASTER IN TERMS OF PUSHING THE COLD FRONT ACROSS THE
REGION. BELIEVE THIS MAY BE TO AGGRESSIVE AS THE RIDGE OVER THE AREA
IS PRETTY POTENT. THEREFORE OVERALL TRENDS IN THE FORECAST LEANED
MORE TOWARDS HPC/EC FOR THE LONG TERM.
DETAILS...
THURSDAY...
SURFACE LOW WILL MOVE OFF SHORE ON THURSDAY. THIS WILL
DROP A BOUNDARY ACROSS THE SOUTHERN ZONES. MODELS HAVE A LARGE
DISCREPANCY ON TEMPS...LEAN TOWARDS THE COLDER SOLUTION DUE TO THE
STRONG HIGH PRESSURE THAT IS SET UP ACROSS THE HUDSON BAY REGION.
THIS COMBINED WITH THE NORTHERNLY TEMPS PULLING IN A COLD AIR
DAMMING SIGNATURE...GIVES GREATER WEIGHT TOWARDS THE BELOW AVG
TEMPS. SCT RAIN SHOWERS...DRIZZLE IS ALSO POSSIBLE ON THURSDAY
ACROSS THE BOUNDARY. TEMPS WILL DROP OVERNIGHT CLOSE TO THE FREEZING
MARK...ESP ACROSS NH AND NORTHERN MASS. THIS WILL ALLOW FOR THE
POSSIBILITY OF RAIN/SLEET OVERNIGHT WITHIN ANY SHOWERS THAT DEVELOP.
FRIDAY...
HIGHER CONFIDENCE ON THIS FORECAST AS A STRONG COLD FRONT
WILL PUSH ACROSS NEW ENGLAND. STILL SOME DIFFERENCES ON THE SURFACE
LOW EXACT POSITION AND TIMING. THE NAM IS THE FASTEST OF THE
SOLUTIONS WHERE AS THE EC IS THE SLOWEST. SEEMS THAT THE NAM AND GFS
ARE BREAKING DOWN THE RIDGE QUICKER THAN THE EC. TRENDED THIS
PORTION OF THE FORECAST TO A 2:1 EC TO GFS. BELIEVE THE HEAVIER
PRECIP WILL OCCUR BY THE LATER AFTERNOON INTO THE EVENING
HOURS...WHICH WILL IMPACT THE FRIDAY EVENING COMMUTE. PWAT VALUES
AVERAGE AROUND 1.5 INCHES AND THERE IS A GOOD AMOUNT OF MOISTURE
TRANSPORT THANKS TO A STRENGTHENING LLJ AT 850MB. BELIEVE THAT HEAVY
DOWNPOURS ARE LIKELY WHICH COULD RESULT IN SOME URBAN POOR DRAINAGE
FLOODING. BECAUSE THIS SYSTEM WILL QUICKLY MOVE ACROSS SNE...BELIEVE
THERE IS A LOW PROBABILITY FOR RIVER FLOODING...BUT HAVE LOW
CONFIDENCE ON THIS. DUE TO THE STRENGTHEN LLJ WIND GUSTS COULD
INCREASE SIGNIFICANTLY...AROUND 25-35 MPH. LOW CONFIDENCE ON IT
HITTING WIND CRITERIA AS DO NOT BELIEVE THAT MIXING WILL BE QUITE
DOMINATE AHEAD OF THE FRONT. AS THE COLD FRONT MOVES THROUGH...TEMPS
WILL DROP AS CAA PUSHES THROUGH.
SATURDAY INTO SUNDAY...
PLEASANT SPRING LIKE DAYS ARE IN STORE FOR THE WEEKEND. SURFACE
LOW WILL PUSH OFFSHORE BY SATURDAY. YET LAGGING UPPER LEVEL TROUGH
WILL MOVE THOUGH OVER THE WEEKEND. FOLLOWED BY SURFACE HIGH
PRESSURE BUILDING. THIS WILL ALLOW FOR A MIXTURE OF SUN AND
CLOUDS. DRY AIR ACROSS THE AREA WILL LEAD TO MAINLY DRY WEATHER.
AS CAA STILL MIXES IN TEMPS OVERNIGHT WILL DROP IN THE LOW 30S.
EARLY WORK WEEK...
UPPER LEVEL RIDGING AXIS WILL PASS ACROSS SNE BY MONDAY. THIS
WILL ALLOW FOR MODERATING TEMPS BACK INTO THE 60S ACROSS THE
REGION WITH PERHAPS 70S BY TUESDAY. THIS IS PLAUSIBLE IS SHORTWAVE
WILL REMAIN NORTH OF THE REGION...PERHAPS A FEW SCT/ISO SHOWERS
ACROSS NORTHERN ZONES BY EARLY NEXT WEEK. LOW CONFIDENCE ON
TIMING.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...HIGH CONFIDENCE THROUGH MIDNIGHT. THEREAFTER...LOW TO
MODERATE CONFIDENCE THROUGH WEDNESDAY NIGHT.
TONIGHT...VFR CONDITIONS WILL CONTINUE FOR MOST OF THE NIGHT. A
BAND OF SHOWERS LATE MAY RESULT IN SOME MVFR TO ISOLATED IFR
CONDITIONS NEAR DAYBREAK WEDNESDAY. BEST CHANCE FOR LOW CONDITIONS
AND SHOWERS WILL BE NORTH OF THE MA TURNPIKE.
WEDNESDAY AND WEDNESDAY NIGHT...MOST OF THE SHOWERS SHOULD EXIT
THE REGION BY MID MORNING ON WED. MVFR TO IFR CONDITIONS MAY
TEMPORARY IMPROVE TO VFR LATE WED MORNING/EARLY AFTERNOON. ANOTHER
ROUND OF MVFR-IFR CONDITIONS WILL PROBABLY DEVELOP WED NIGHT ALONG
WITH ANOTHER BATCH OF SHOWERS.
KBOS TERMINAL...HIGH CONFIDENCE THROUGH AT LEAST MIDNIGHT IN VFR
CONDITIONS. WE DID INSERT A SEA BREEZE FROM 21Z TO 00Z...BASED ON
OBS JUST SOUTH AND EAST OF THE TERMINAL AND WEAKENING GRADIENT.
MODERATE CONFIDENCE ON WEDNESDAY ON CIGS/VSBYS. HIGH CONFIDENCE IN
EASTERLY SEA BREEZES ON WEDNESDAY.
KBDL TERMINAL...HIGH CONFIDENCE THROUGH AT LEAST MIDNIGHT.
MODERATE CONFIDENCE ON WEDNESDAY.
OUTLOOK...THURSDAY THROUGH SUNDAY...
MODERATE CONFIDENCE ALL PERIODS.
THURSDAY... MAINLY VFR. SMALL CHANCE FOR ISOLATED MVFR IN CIGS
THROUGH THE DAY.
FRIDAY...MVFR/IFR IN RAIN. EAST TO SOUTHEAST WINDS AT THE SURFACE
WITH SOUTHWEST WINDS INCREASING TO 50-60 KNOTS 2000-4000 FEET
ABOVE THE SURFACE AND PROVIDING LOW LEVEL WIND SHEAR.
SATURDAY INTO SUNDAY...VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
SCA FOR REMAINING OUTER WATERS WILL EXPIRE AT 11 PM EDT AS SEAS
CONTINUE TO SUBSIDE. BUOY SE OF BLOCK ISLAND /44097/ REPORTING 5
FT SEAS THIS EVENING. OTHERWISE LIGHT WINDS AND FLAT SEAS
EXPECTED OVERNIGHT.
LIGHT E/NE FLOW PERSISTS WED/WED NIGHT WITH LOCAL SEA BREEZES
EXPECTED FROM LATE MORNING INTO AFTERNOON.
OUTLOOK...THURSDAY THROUGH SUNDAY...
MODERATE CONFIDENCE ALL PERIODS.
THURSDAY...BOUNDARY ACROSS THE SOUTHERN WATERS WILL ALLOW FOR
GUSTS NEAR 25 KTS AND SEAS TO INCREASE AOA 5FT. MOD CONFIDENCE IF
SCA WILL BE NEEDED.
FRIDAY... STRONG COLD FRONT WILL PUSH THROUGH INCREASING GUSTS
25-30KTS. LOW PROB FOR GALES DURING THE DAY ACROSS THE SOUTHERN
WATERS AND MOD PROB FOR GALES ACROSS THE EASTERN WATERS BY FRIDAY
NIGHT. HEAVY RAIN MAY REDUCE VSBYS ACROSS THE WATERS.
SATURDAY INTO SUNDAY... NORTHWEST WINDS GUSTING TO 25 KNOTS DUE TO
CAA. SEAS REMAIN ABOVE 5 FEET ESPECIALLY ON THE OUTER WATERS.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 PM EDT THIS EVENING FOR
ANZ254>256.
&&
$$
SYNOPSIS...FRANK/DUNTEN
NEAR TERM...JWD
SHORT TERM...FRANK
LONG TERM...DUNTEN
AVIATION...FRANK/DUNTEN
MARINE...FRANK/DUNTEN
AREA FORECAST DISCUSSION
NWS NEW YORK NY
203 AM EDT MON APR 8 2013
.SYNOPSIS...
A COLD FRONT PUSHES INTO THE REGION OVERNIGHT...THEN LIFTS TO THE
NORTH ON MONDAY. THIS FRONT THEN REMAINS NEAR THE AREA INTO
FRIDAY WITH WAVES OF LOW PRESSURE RIDING ALONG THE BOUNDARY. A
DEEPER LOW MOVES THROUGH THE REGION FRIDAY NIGHT INTO SATURDAY
CARRYING THE A COLD EAST OF THE REGION SATURDAY MORNING. HIGH
PRESSURE BUILDS IN FOR SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
BASED ON LATEST SATELLITE TRENDS SHOWING CLOUD COVER FROM PA BACK
INTO OHIO VALLEY HEADED EAST IN ZONAL FLOW ALOFT - HAVE INCREASED
CLOUD COVER OVERNIGHT. LATEST RADAR RETURNS AND RUC ANALYSIS
SHOWING NO UPSTREAM VORTICITY MAXIMUM TO MOVE THROUGH OVERNIGHT -
SUPPORT A DRY FORECAST.
MINOR CHANGES MADE TO TEMPERATURES/DEWPOINTS REFLECTING BLEND OF
LAV/MET/MAV GUIDANCE. STILL ON TRACK FOR LOWS AROUND 5 DEGREES
ABOVE NORMAL - MAYBE A TAD HIGHER IN NYC.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
A DRY MONDAY IS EXPECTED AS A BRIEF PERIOD OF WEAK RIDGING WILL
MOVE OVER THE REGION. DAYTIME HIGH TEMPERATURES ARE EXPECTED TO
CLIMB INTO THE UPPER 60S AND LOWER 70S ACROSS THE INTERIOR.
ACROSS THE COASTAL LOCATIONS...HIGHS WILL REACH THE LOWER AND
MIDDLE 60S...COURTESY OF AN ONSHORE FLOW. THIS WILL BE ABOUT 10
DEGREES ABOVE NORMAL. FOLLOWED A MAV/MET BLEND.
CLOUDY SKIES AND A CHANCE OF SHOWERS RETURNS TO THE FORECAST
MONDAY NIGHT...IN RESPONSE TO ANOTHER PASSING MID-LEVEL SHORTWAVE
AND THE PASSAGE OF AN 850 WARM FRONT. WILL KEEP POPS AT CHANCE
FOR NOW. FOLLOWED A MAV/MET BLEND FOR OVERNIGHT LOWS. TEMPERATURES
ARE EXPECTED TO ONLY FALL INTO THE UPPER 40S AND LOWER 50S...ABOUT
10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MUCH OF THE LONG RANGE FORECAST REMAINS UNCERTAIN AND WILL BE
HIGHLY DEPENDENT ON THE SETUP OF A FRONTAL BOUNDARY. CURRENT
THINKING AND RECENT MODEL RUNS KEEP THE BOUNDARY JUST NORTH OF THE
AREA. THIS WILL RESULT IN A WARM AIRMASS ACROSS THE REGION...WITH
COASTAL AREAS REMAINING COOLER IN THE SOUTHERLY FLOW. CLOUDS WILL
BE IN THE VICINITY TUESDAY AND WITH THE FRONTAL BOUNDARY IN THE
AREA...LOWERED THE HIGHS FOR TUESDAY. HOWEVER MODEL SPREAD
INDICATES HIGHS INLAND FROM 70 TO 79...AND ALONG THE COAST FROM 62
TO 75...WITH THE UNCERTAINTY FORECAST HIGHS SOMEWHERE ABOUT IN THE
MIDDLE OF THE SPREAD. WIDE SPREADS IN FORECAST HIGHS AND LOWS
REMAIN WEDNESDAY INTO FRIDAY. WITH WAVES OF LOW PRESSURE EXPECTED
TO TRACK ALONG THE FRONTAL BOUNDARY AND EMBEDDED SHORTWAVES ALSO
TRAVEL THROUGH THE UPPER ZONAL FLOW THERE WILL BE A CHANCE OF
SHOWERS TUESDAY NIGHT INTO SATURDAY. ELEVATED INSTABILITY WILL BE
VERY MARGINAL AND AVAILABLE MIXED LAYER CAPE WILL BE NEAR ZERO
WITH HIGHER CINS...SO REMOVED MENTION OF THUNDER.
BEST CHANCE OF SHOWERS WILL BE A DEEPER SHORTWAVE AND VORTICITY
MAXIMUM MOVING OUT OF THE NORTHERN PLAINS AND INTO THE NORTHEAST
FRIDAY AND FRIDAY NIGHT...AND THUS WILL HAVE THE HIGHEST POPS OF
THE EXTENDED DURING THIS TIME FROM. RATHER STRONG COLD FRONT WILL
BE PASSING THROUGH WITH THIS WAVE WITH TEMPERATURES RETURNING TO
BELOW NORMAL SEASONAL LEVELS FOR NEXT WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
VFR TODAY WITH LIGHT BUT SHIFTING WINDS AS A WEAK COLD FRONT
STALLS OVER THE AREA.
LOCALIZED LIGHT FOG IS POSSIBLE OUTSIDE OF THE NY METRO PRIOR TO
SUNRISE OTHERWISE NO RESTRICTIONS. LIGHT WINDS VEER THIS MORNING
WITH A LIGHT NORTHERLY FLOW BEFORE SEA BREEZE CIRCULATION DEVELOP
THIS AFTERNOON ALONG COASTAL AREAS. TIMING OF WIND DIRECTIONS
CHANGES COULD BE OF BY + OR - 2 HOURS.
.OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MON NIGHT...MVFR IN BR POSSIBLE WITH LOW CHC OF IFR CIGS.
.TUE-THU...GENERALLY VFR. SUB-VFR MAY OCCUR AT TIMES IN
SCATTERED RAIN SHOWERS WITH ISOLATED TSTMS. LGT WNDS.
.FRI...OCNL MVFR IN SCATTERED SHRA AND TSTMS.
&&
.MARINE...
WINDS HAVE FALLEN BELOW SCA LEVELS ON THE COASTAL OCEAN ZONES AND
WILL CONTINUE TO FALL OVERNIGHT. SEAS REMAIN RIGHT BELOW 5 FT -
AND WITH DIMINISHING WINDS DO NOT EXPECT THEM TO INCREASE ANY - IN
FACT WOULD EXPECT A SLIGHT FALL OFF. AS A RESULT HAVE CANCELLED
THE SMALL CRAFT ADVISORY FOR THE COASTAL OCEAN WATERS.
ALL WATERS WILL BE BELOW SMALL CRAFT LEVELS ON MONDAY BEFORE SEAS
INCREASE ONCE AGAIN MONDAY NIGHT.
SEAS ON THE OCEAN WATERS WILL LIKELY STILL BE AT OR ABOVE 5 FT
TUESDAY MORNING AS A STRONG SOUTHERLY FLOW CONTINUES. AS THE FLOW
DIMINISHES THROUGH THE DAY AND INTO TUESDAY NIGHT SEAS WILL ALSO
SUBSIDE AND DROP BELOW SMALL CRAFT DURING THE EVENING. THE
FORECAST OF WINDS AND SEAS WILL BE DEPENDENT ON WHERE A FRONTAL
BOUNDARY BECOMES STATIONARY IN THE VICINITY. CURRENT THINKING IS
THAT THE FRONT WILL BE JUST NORTH OF THE WATERS THROUGH THURSDAY
NIGHT. A SOUTHERLY FLOW WILL PERSIST AND WINDS WILL REMAIN BELOW
SMALL CRAFT. HOWEVER...BY WEDNESDAY NIGHT SEAS ON THE OCEAN WATERS
ARE EXPECTED TO BUILD BACK TO SMALL CRAFT WITH A STRENGTHENING AND
PERSISTENT SOUTH FLOW. AND THEN SUBSIDE AGAIN AS A DEEPER WAVE OF
LOW PRESSURE RIDES ALONG THE STALLED FRONTAL BOUNDARY...AND THE
GRADIENT BECOMES RATHER WEAK. THEN A NORTHWEST FLOW SETS UP BEHIND
THE DEPARTING LOW FRIDAY NIGHT INTO SATURDAY. GUSTS AT THAT TIME
FRAME MAY BE NEAR SMALL CRAFT.
&&
.HYDROLOGY...
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED THROUGH
THURSDAY. THERE IS A HIGH DEGREE OF UNCERTAINTY WITH THE FORECAST
THROUGH THE WEEK AND ANY PRECIPITATION AND AMOUNTS WILL BE
DEPENDENT ON WHERE A FRONTAL BOUNDARY SETS UP AND THE TIMING OF
WAVES OF LOW PRESSURE MOVING ALONG THE BOUNDARY. THE BEST CHANCE
FOR SIGNIFICANT RAINFALL APPEARS TO BE LATE IN THE WEEK...THURSDAY
NIGHT INTO FRIDAY NIGHT...WITH INCREASING PRECIPITABLE WATER
VALUES ACROSS THE REGION...AND FAIRLY STRONG FORCING AVAILABLE TO
ACT ON THIS MOISTURE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...BC/MET
NEAR TERM...MALOIT
SHORT TERM...BC
LONG TERM...MET
AVIATION...TONGUE
MARINE...BC/MALOIT/MET/PW
HYDROLOGY...BC/MET
AREA FORECAST DISCUSSION
NWS NEW YORK NY
1239 AM EDT MON APR 8 2013
.SYNOPSIS...
A COLD FRONT PUSHES INTO THE REGION OVERNIGHT...THEN LIFTS TO THE
NORTH ON MONDAY. THIS FRONT THEN REMAINS NEAR THE AREA INTO
FRIDAY WITH WAVES OF LOW PRESSURE RIDING ALONG THE BOUNDARY. A
DEEPER LOW MOVES THROUGH THE REGION FRIDAY NIGHT INTO SATURDAY
CARRYING THE A COLD EAST OF THE REGION SATURDAY MORNING. HIGH
PRESSURE BUILDS IN FOR SATURDAY AND SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
BASED ON LATEST SATELLITE TRENDS SHOWING CLOUD COVER FROM PA BACK
INTO OHIO VALLEY HEADED EAST IN ZONAL FLOW ALOFT - HAVE INCREASED
CLOUD COVER OVERNIGHT. LATEST RADAR RETURNS AND RUC ANALYSIS
SHOWING NO UPSTREAM VORTICITY MAXIMUM TO MOVE THROUGH OVERNIGHT -
SUPPORT A DRY FORECAST.
MINOR CHANGES MADE TO TEMPERATURES/DEWPOINTS REFLECTING BLEND OF
LAV/MET/MAV GUIDANCE. STILL ON TRACK FOR LOWS AROUND 5 DEGREES
ABOVE NORMAL - MAYBE A TAD HIGHER IN NYC.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/...
A DRY MONDAY IS EXPECTED AS A BRIEF PERIOD OF WEAK RIDGING WILL
MOVE OVER THE REGION. DAYTIME HIGH TEMPERATURES ARE EXPECTED TO
CLIMB INTO THE UPPER 60S AND LOWER 70S ACROSS THE INTERIOR.
ACROSS THE COASTAL LOCATIONS...HIGHS WILL REACH THE LOWER AND
MIDDLE 60S...COURTESY OF AN ONSHORE FLOW. THIS WILL BE ABOUT 10
DEGREES ABOVE NORMAL. FOLLOWED A MAV/MET BLEND.
CLOUDY SKIES AND A CHANCE OF SHOWERS RETURNS TO THE FORECAST
MONDAY NIGHT...IN RESPONSE TO ANOTHER PASSING MID-LEVEL SHORTWAVE
AND THE PASSAGE OF AN 850 WARM FRONT. WILL KEEP POPS AT CHANCE
FOR NOW. FOLLOWED A MAV/MET BLEND FOR OVERNIGHT LOWS. TEMPERATURES
ARE EXPECTED TO ONLY FALL INTO THE UPPER 40S AND LOWER 50S...ABOUT
10 DEGREES ABOVE NORMAL.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
MUCH OF THE LONG RANGE FORECAST REMAINS UNCERTAIN AND WILL BE
HIGHLY DEPENDENT ON THE SETUP OF A FRONTAL BOUNDARY. CURRENT
THINKING AND RECENT MODEL RUNS KEEP THE BOUNDARY JUST NORTH OF THE
AREA. THIS WILL RESULT IN A WARM AIRMASS ACROSS THE REGION...WITH
COASTAL AREAS REMAINING COOLER IN THE SOUTHERLY FLOW. CLOUDS WILL
BE IN THE VICINITY TUESDAY AND WITH THE FRONTAL BOUNDARY IN THE
AREA...LOWERED THE HIGHS FOR TUESDAY. HOWEVER MODEL SPREAD
INDICATES HIGHS INLAND FROM 70 TO 79...AND ALONG THE COAST FROM 62
TO 75...WITH THE UNCERTAINTY FORECAST HIGHS SOMEWHERE ABOUT IN THE
MIDDLE OF THE SPREAD. WIDE SPREADS IN FORECAST HIGHS AND LOWS
REMAIN WEDNESDAY INTO FRIDAY. WITH WAVES OF LOW PRESSURE EXPECTED
TO TRACK ALONG THE FRONTAL BOUNDARY AND EMBEDDED SHORTWAVES ALSO
TRAVEL THROUGH THE UPPER ZONAL FLOW THERE WILL BE A CHANCE OF
SHOWERS TUESDAY NIGHT INTO SATURDAY. ELEVATED INSTABILITY WILL BE
VERY MARGINAL AND AVAILABLE MIXED LAYER CAPE WILL BE NEAR ZERO
WITH HIGHER CINS...SO REMOVED MENTION OF THUNDER.
BEST CHANCE OF SHOWERS WILL BE A DEEPER SHORTWAVE AND VORTICITY
MAXIMUM MOVING OUT OF THE NORTHERN PLAINS AND INTO THE NORTHEAST
FRIDAY AND FRIDAY NIGHT...AND THUS WILL HAVE THE HIGHEST POPS OF
THE EXTENDED DURING THIS TIME FROM. RATHER STRONG COLD FRONT WILL
BE PASSING THROUGH WITH THIS WAVE WITH TEMPERATURES RETURNING TO
BELOW NORMAL SEASONAL LEVELS FOR NEXT WEEKEND.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
A COLD FRONT APPROACHES FROM THE WEST AND STALLS OVER THE AREA
OVERNIGHT THROUGH MONDAY.
GENERALLY VFR. AFTER MIDNIGHT...PATCHY FOG MAY DEVELOP OUTSIDE OF
NYC METRO TERMINALS. CONFIDENCE IS LOW THOUGH. OVERALL...LOCAL
MVFR VSBYS CAN NOT BE RULED OUT. OTHERWISE MID AND HIGH CLOUDS
DEPART.
WINDS ARE LIGHTENING AS EXPECTED FROM THE SOUTH THIS
EVENING...THEN TURN TOWARD THE WEST/SOUTHWEST AFTER MIDNIGHT.
ALTHOUGH LOW LEVEL WIND SHEAR IS ONLY INDICATED AT KISP...NOTE
THAT 40-50 KT WINDS ARE POSSIBLE AT 2000FT AT MOST OF THE OTHER
TERMINALS THROUGH MIDNIGHT OR SO.
WINDS TURN TOWARD THE NORTHWEST AFTER SUNRISE MONDAY...BUT REMAIN
UNDER 10 KTS. THEN WINDS TURN BACK TO THE SOUTH DURING THE
AFTERNOON. PLEASE SEE INDIVIDUAL TERMINAL FORECASTS FOR BEST
ESTIMATE ON TIMING OF WIND SHIFTS. ALL WIND SHIFTS COULD BE OFF BY
AN HOUR OR TWO.
.OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY...
.MONDAY NIGHT...SUB-VFR IS POSSIBLE IN PATCHY FOG AND STRATUS.
SHOWERS ARE ALSO POSSIBLE.
.TUESDAY-FRIDAY...GENERALLY VFR BUT SUB-VFR MAY OCCUR AT TIMES IN
RAIN SHOWERS WITH ISOLATED TSTMS.
&&
.MARINE...
WINDS HAVE FALLEN BELOW SCA LEVELS ON THE COASTAL OCEAN ZONES AND
WILL CONTINUE TO FALL OVERNIGHT. SEAS REMAIN RIGHT BELOW 5 FT -
AND WITH DIMINISHING WINDS DO NOT EXPECT THEM TO INCREASE ANY - IN
FACT WOULD EXPECT A SLIGHT FALL OFF. AS A RESULT HAVE CANCELLED
THE SMALL CRAFT ADVISORY FOR THE COASTAL OCEAN WATERS.
ALL WATERS WILL BE BELOW SMALL CRAFT LEVELS ON MONDAY BEFORE SEAS
INCREASE ONCE AGAIN MONDAY NIGHT.
SEAS ON THE OCEAN WATERS WILL LIKELY STILL BE AT OR ABOVE 5 FT
TUESDAY MORNING AS A STRONG SOUTHERLY FLOW CONTINUES. AS THE FLOW
DIMINISHES THROUGH THE DAY AND INTO TUESDAY NIGHT SEAS WILL ALSO
SUBSIDE AND DROP BELOW SMALL CRAFT DURING THE EVENING. THE
FORECAST OF WINDS AND SEAS WILL BE DEPENDENT ON WHERE A FRONTAL
BOUNDARY BECOMES STATIONARY IN THE VICINITY. CURRENT THINKING IS
THAT THE FRONT WILL BE JUST NORTH OF THE WATERS THROUGH THURSDAY
NIGHT. A SOUTHERLY FLOW WILL PERSIST AND WINDS WILL REMAIN BELOW
SMALL CRAFT. HOWEVER...BY WEDNESDAY NIGHT SEAS ON THE OCEAN WATERS
ARE EXPECTED TO BUILD BACK TO SMALL CRAFT WITH A STRENGTHENING AND
PERSISTENT SOUTH FLOW. AND THEN SUBSIDE AGAIN AS A DEEPER WAVE OF
LOW PRESSURE RIDES ALONG THE STALLED FRONTAL BOUNDARY...AND THE
GRADIENT BECOMES RATHER WEAK. THEN A NORTHWEST FLOW SETS UP BEHIND
THE DEPARTING LOW FRIDAY NIGHT INTO SATURDAY. GUSTS AT THAT TIME
FRAME MAY BE NEAR SMALL CRAFT.
&&
.HYDROLOGY...
NO SIGNIFICANT WIDESPREAD PRECIPITATION IS EXPECTED THROUGH
THURSDAY. THERE IS A HIGH DEGREE OF UNCERTAINTY WITH THE FORECAST
THROUGH THE WEEK AND ANY PRECIPITATION AND AMOUNTS WILL BE
DEPENDENT ON WHERE A FRONTAL BOUNDARY SETS UP AND THE TIMING OF
WAVES OF LOW PRESSURE MOVING ALONG THE BOUNDARY. THE BEST CHANCE
FOR SIGNIFICANT RAINFALL APPEARS TO BE LATE IN THE WEEK...THURSDAY
NIGHT INTO FRIDAY NIGHT...WITH INCREASING PRECIPITABLE WATER
VALUES ACROSS THE REGION...AND FAIRLY STRONG FORCING AVAILABLE TO
ACT ON THIS MOISTURE.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...MALOIT/BC/MET
NEAR TERM...MALOIT
SHORT TERM...BC
LONG TERM...MET
AVIATION...PW
MARINE...MALOIT/BC/MET
HYDROLOGY...BC/MET
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
315 PM EDT MON APR 8 2013
.DISCUSSION...
TONIGHT-TUESDAY...
LITTLE CHANGE IN THE CURRENT SYNOPTIC PATTERN. RIDGE AXIS OVER THE W
ATLC/NRN GULF COAST WILL MAINTAIN A STEADY E/SE LOW LVL FLOW ACRS
THE FL PENINSULA...AS WELL AS A STRONG SUBSIDENCE INVERSION IN THE
H85-H70 LYR. LATEST RAP ANALYSIS SHOWS A SINKING AIRMASS ACRS THE
REGION WITH POSITIVE OMEGA VALUES IN THE H85-H30 LYR AND NEGATIVE
DIVERGENCE VALUES IN THE H30-H20 LYR...NO SIG MID LVL VORT MAXES TO
SPEAK OF.
THE ONSHORE LOW LVL FLOW WILL TAP A RESPECTABLE AMOUNT OF LOW LVL
MOISTURE JUST OFFSHORE (H100-H85 MEAN RH AOA 80PCT). HOWEVER... NONE
OF THE LOW-TOPPED SHRAS THE KMLB RADAR HAS BEEN DETECTING OVER THE
GULF STREAM HAVE BEEN ABLE TO SURVIVE FOR LONG ONCE THEY MOVE INTO
THE COOLER SHELF WATERS. IN ORDER TO DO SO WITH A SUBSIDENCE
INVERSION CAPPING THE AIRMASS BLO 7KFT AND THE ABSENCE OF MID/UPR
LVL FORCING...LOW LVL WINDS WOULD NEED TO BE A GOOD 15KTS AND ALMOST
NORMAL TO THE COAST. ANTICIPATED POSITION OF THE RIDGE WILL NOT
ALLOW THIS TYPE OF WIND FIELD TO DVLP. CONTINUED DRY FCST.
PERSISTENT ONSHORE FLOW WILL CONTINUE TO GENERATE COOLER DAYS/WARMER
NIGHTS ALONG THE COAST THAN THE INTERIOR. MINS IN THE M60S ALONG THE
COAST...L60S INTERIOR. MAXES IN THE L80S ALONG COAST...M80S INTERIOR.
WED...THE RIDGING ALOFT SHOULD BEGIN TO WEAKEN AND LOW LEVEL FLOW
WILL TURN TO THE SOUTHEAST. HIGHER MOISTURE VALUES WILL BRING A
SLIGHT CHANCE OF SHOWERS. TEMPS WILL BE ABOVE NORMAL WITH HIGHS
IN THE LOWER 80S ALONG THE COAST AND MID 80S INLAND. OVERNIGHT
LOWS SHOULD BE EVEN MORE ABOVE NORMAL...IN THE MID TO UPPER 60S.
THU-FRI...(MODIFIED PREVIOUS DISC) RECENT GUIDANCE COMING INTO
BETTER AGREEMENT WITH THE TIMING OF THE NEXT FRONT. THE 12Z GFS
REMAINS SLIGHTLY FASTER THAN THE ECMWF BUT NOT AS MUCH SO AS
RECENT CYCLES. PRE-FRONTAL MOISTENING FROM INCREASING SOUTHERLY
WINDS WILL BOOST POPS...REACHING 40 PERCENT ON FRI. TEMPS WILL
ALSO INCREASE WITH MID 80S AREAWIDE BOTH DAYS AND SOME UPPER 80S
TO AROUND 90 OCCURRING IN THE SOUTH.
SAT-MON...NCEP INDICATES WEAKENING FRONTAL BOUNDARY STALLING
OVER THE SOUTH PENINSULA BY SUNDAY AND WASHING OUT BY MON. THIS
LOOKS TO BE A GOOD COMPROMISE BETWEEN FASTER GFS AND SLOWER
ECMWF...GIVEN THAT FRONTS OFTEN DIE OUT SOMEWHERE OVER FLORIDA
THIS TIME OF THE YEAR.
&&
.AVIATION...
THRU 09/18Z...PREVAILING VFR ALL SITES. BTWN 09/08Z-09/13Z...LCL
MVFR CIGS IN BR.
&&
.MARINE...
TONIGHT-TUESDAY...RIDGE AXIS OVER THE ATLC WILL MAINTAIN A GENTLE TO
MODERATE E/SE BREEZE ACRS THE LCL ATLC...AS WELL AS A 3-4FT ERLY
SWELL...DOMINANT PDS 9-10 SEC. COMBINED SEAS 3-4FT NEARSHORE AND
4-5FT OFFSHORE...BCMG 4-5FT AREAWIDE.
WED-FRI...INITIALLY ONSHORE FLOW WILL OCCUR AS RIDGE AXIS REMAINS
TO OUR NORTH. SPEEDS INCREASE TO 15 KNOTS AND GUSTY WED. FLOW LOOKS
TO BE SOUTHEAST-SOUTH ON THU AT 15-20 KNOTS THEN SOUTH-SOUTHWEST
15-20 KNOTS FRI. A SLIGHT CHANCE FOR STORMS EXISTS FOR THU AND
FRI AND A CHANCE FOR AFTERNOON-EVENING STORMS MOVING OFF THE
MAINLAND EXISTS.
&&
.FIRE WEATHER...
E/SE SFC/TRANSPORT FLOW BCMG S/SE THRU MIDWEEK...NO WIND/RH CONCERNS
ANTICIPATED.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 63 80 65 80 / 0 10 10 10
MCO 62 85 64 86 / 0 10 10 20
MLB 64 81 69 83 / 0 10 10 20
VRB 65 81 68 81 / 10 10 10 20
LEE 61 85 63 85 / 0 0 10 20
SFB 62 85 64 85 / 0 10 10 20
ORL 62 85 65 85 / 0 10 10 20
FPR 65 81 69 82 / 10 10 10 20
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM...BRAGAW
LONG TERM....PENDERGRAST
AREA FORECAST DISCUSSION
NWS MELBOURNE FL
1030 AM EDT MON APR 8 2013
.DISCUSSION...
HIGH PRESSURE ANCHORED E OF THE CAROLINA COAST EXTENDING WEST ACRS
THE NRN GULF COAST WILL GENERATE A STEADY E/SE BREEZE ACRS THE FL
PENINSULA. UPSTREAM LOW LVL MOISTURE VALUES ARE RUNNING 75-80PCT...
HIGH ENOUGH TO GENERATE RESPECTABLE CLOUD COVER AS WELL AS ISOLD
-SHRAS OVER THE GULF STREAM.
WHILE RADAR HAS BEEN DETECTING THE FOR THE PAST SVRL HRS...NONE OF
THEM HAVE SURVIVED FOR LONG ONCE THEY MOVE OUT OF THE GULF STREAM
INTO THE COOLER SHELF WATERS. MORNING SOUNDINGS ALL SHOW A SHARP
SUBSIDENCE INVERSION IN THE H85-H70 LYR CAPPING THE LCL AIRMASS BTWN
6-7KT WITH PWAT VALUES AOB 1.0". FURTHERMORE...THE USAF 915HZ
PROFILER AT THE CAPE INDICATING WINDS A BIT MORE SE TODAY THAN
SUNDAY...AND ONLY 10-15KTS AT THAT.
LITTLE TO NO CHANCE ANY SHRAS WILL MAKE IT ONSHORE...IMPACT OF ANY
THAT DO WOULD BE NEGLIGIBLE. FCST WILL REMAIN DRY. MORNING PACKAGE
LOOKS FINE AS IT...NO NEED TO UPDATE THIS MORNING.
&&
.AVIATION...
THRU 09/18Z...PREVAILING VFR ALL SITES. BTWN 09/08Z-09/13Z...LCL
MVFR CIGS IN BR.
&&
.MARINE...
NO HIGHLIGHTS. RIDGE AXIS WILL GENERATE A LIGHT TO GENTLE E/SE
BREEZE ACRS THE LCL ATLC. THESE WINDS WILL CONTINUE TO PUSH A 3-4FT
SWELL TOWARD THE E FL COAST...DOMINANT PDS 9-10 SEC. RAP ANALYSIS
SHOWS THE FETCH AROUND THE BASE OF THE RIDGE HAS A MORE MORE ERLY
DIRECTION TODAY THAN SUNDAY...ALSO A BIT WEAKER AT 10-15KTS. LATEST
BUOY OBS INDICATE SEAS ARE RUNNING ABOUT A FOOT LOWER THAN FCST...
REASONABLE GIVEN THE WEAKER WIND FIELD...SUSPECT THE NRN BAHAMAS
ALSO INTERCEPTING SOME OF THE SWELL ENERGY. WILL MAKE NECESSARY
ADJUSTMENTS.
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
&&
$$
SHORT TERM/AVIATION...BRAGAW
LONG TERM/IMPACT WX...PENDERGRAST
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
858 AM EDT Mon Apr 8 2013
.NEAR TERM [Rest of Today into this Evening]...
The large scale longwave pattern is highlighted by digging trough
over Wrn states with low at base over Ern NV and a broad ridge Ewd
across Srn stream. At surface, high pressure is centered in Wrn Atlc
off Carolina coast with ridging Wwd across local area, FL Peninsula
and into Gulf of Mex. Nearest low pressure center OK/TX panhandle
with front Swd down TX into Old Mex.
During the rest of today into this eve, as a strong impulse with
100+ NNW winds dives SEWD from Ern most Pacific into CA, Wrn
trough will continue to amplify SEWD across Great Basin towards 4
Corners. In response mid/upper ridge will also amplify N/NE with
rising heights over Gulf of Mex and SE region. At surface, OK/TX
low moves Ewd while high drops Swd in Wrn Atlc resulting in local
flow veering to SE/S around Wrn periphery of this high.
All this will yield somewhat tighter local gradients with a
modest increase in winds and warmer than normal temperatures.
1000-850mb thickness supports inland highs 80 West to 84 East.
These same conditions moving off cooler waters should maintain
beach temps in the the low 70s. Local obs show broken 6k clouds
across Ern counties this morning and area RAP sounding shows
moisture pooling up to H85 so expect CU clouds to again develop
this aftn. Will tweak aftn sky group to reflect this. No rain is
expected.Later tonight, this veering flow will provide sufficient
low level moisture for at least patchy fog.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 80 56 84 58 85 / 0 0 0 0 10
Panama City 77 63 83 63 81 / 0 0 0 0 10
Dothan 81 59 85 61 85 / 0 0 0 0 10
Albany 82 59 85 61 85 / 0 0 0 0 10
Valdosta 82 57 85 60 85 / 0 0 0 0 10
Cross City 82 56 84 61 85 / 0 0 0 0 10
Apalachicola 74 61 78 62 76 / 0 0 0 0 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
Near Term/MARINE/Aviation/Long Term...Block
Short Term/FIRE WEATHER...Camp
HYDROLOGY...DVD
AREA FORECAST DISCUSSION
NWS MIAMI FL
144 AM EDT MON APR 8 2013
.AVIATION...
VFR CONDITIONS TO PREVAIL AT ALL SITES THROUGH THE PERIOD.
GENERALLY LIGHT EASTERLY FLOW IS EXPECTED AT ALL SITES THROUGH THE
MORNING BEFORE INCREASING BY AFTERNOON. KAPF SHOULD SEE A GULF
BREEZE DEVELOP BY MID AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 812 PM EDT SUN APR 7 2013/
UPDATE...
A MID TO UPPER LEVEL TROUGH MOVED THROUGH THE FLORIDA PENINSULA
THIS AFTERNOON ALLOWING FOR A FEW SHOWERS TO DEVELOP OVER THE
AREA. THE TROUGH WILL CONTINUE TO MOVE EAST AWAY FROM SOUTH
FLORIDA TONIGHT...AS THE SURFACE HIGH REMAINS OVER THE WESTERN
ATLANTIC WATERS. THIS WILL ALLOW FOR DRY AIR TO WORK BACK INTO THE
AREA FOR TONIGHT. SO WILL KEEP THE WEATHER DRY OVER SOUTH FLORIDA
TONIGHT ALONG WITH MOSTLY CLEAR TO CLEAR SKIES. TEMPERATURES
TONIGHT SHOULD BE ABLE TO FALL INTO THE 60S TONIGHT OVER SOUTH
FLORIDA...DUE TO THE CLEAR SKIES AND LIGHT WINDS OVERNIGHT.
SO THE ONLY CHANGE TO THE FORECAST FOR TONIGHT IS TO REMOVE THE
AFTERNOON AND EVENING WORDING FROM THE ZONES.
UPDATE...54/BNB
PREV DISCUSSION... /ISSUED 219 PM EDT SUN APR 7 2013/
SHORT TERM (TONIGHT THROUGH TUESDAY NIGHT)...
PLACED AN ISOLATED POP GRID FOR ALL ZONES THE REMAINDER OF THIS
AFTERNOON. THE ONSHORE FLOW OF A FEW SHOWERS ALONG THE EAST COAST
HAS BEEN PERSISTENT AND THE HRRR DOES INDICATE A CONTINUATION OF
ISOLATED ACTIVITY DEVELOPING ACROSS THE INTERIOR AND COASTAL
COLLIER COUNTY UNTIL VERY EARLY THIS EVENING.
GLOBAL MODELS IN VERY GOOD AGREEMENT OVER THE NEXT 48-60 HOURS
WITH MID LEVEL ZONAL FLOW THROUGH EARLY TUESDAY AND SURFACE HIGH
PRESSURE ACROSS THE ATLANTIC AND NORTH FLORIDA. THIS WILL MAINTAIN
A MODEST EASTERLY LOW LEVEL WIND FLOW AND A MOSTLY DRY WEATHER
REGIME WITH STRONG SUBSIDENCE CAP REMAINING INTACT. THERE IS A
SMALL INCREASE IN PWAT VALUES THAT WILL BE ROTATING WESTWARD
BENEATH THE LARGE SCALE LOW LEVEL RIDGE OVER THE ATLANTIC THAT THE
MODELS SHOW ARRIVING ACROSS SOUTH FLORIDA BY LATE TUESDAY AND
TUESDAY NIGHT. FORECAST SOUNDINGS ALSO INDICATE THE CAP WILL BEGIN
TO ERODE BY THIS TIME AND THIS SHOULD ALLOW FOR A SLIGHT INCREASE
IN SHOWER ACTIVITY MOVING FROM THE ATLANTIC ONTO THE SOUTHEAST
COAST. FOR THIS REASON, WILL MAINTAIN A SLIGHT CHANCE POP ALONG
THE EAST COAST TUESDAY NIGHT AND SILENT POP ELSEWHERE AS RAIN
CHANCES OVER THE INTERIOR AND COASTAL COLLIER COUNTY WILL BE TOO
SMALL TO MENTION IN THOSE LOCATIONS. IN ADDITION, THE SHORT RANGE
ENSEMBLE (SREF) IS SHOWING A SUBSTANTIAL INCREASED CHANCE FOR FOG
OVER THE INTERIOR AND SOUTHWEST COAST FOR MONDAY NIGHT AND TUESDAY
NIGHT AS THE LOW LEVEL MOISTURE INCREASES SO WILL INTRODUCE PATCHY
FOG FOR THOSE LOCATIONS AT THAT TIME.
LONG TERM (WEDNESDAY THROUGH SUNDAY)...
LOOKING AHEAD TOWARDS THE MIDDLE AND END OF THE WEEK, THE FORECAST
BECOMES INCREASINGLY UNCERTAIN AS THE GFS AND ECMWF CONTINUE TO
DIVERGE ON THE EVOLUTION OF THE POWERFUL MID LEVEL TROUGH THAT WILL
BE MOVING INTO THE CENTRAL PLAINS STATES MONDAY NIGHT AND TUESDAY
THEN SHIFTING EAST THROUGH THE WEEK. THE GFS PHASES IT IN WITH A
NORTHERN STREAM TROUGH BY LATE WEDNESDAY AND THURSDAY AS THE MAIN
SYSTEM LIFTS EAST INTO THE ATLANTIC. THIS BRINGS A TRAILING COLD
FRONT ACROSS SOUTH FLORIDA ON FRIDAY SLOWLY PUSHING THROUGH THE
REGION AND OFF THE SOUTHEAST COAST LATE SATURDAY AND SUNDAY. THIS
WOULD ALSO BRING AN INCREASED CHANCE FOR CONVECTION ON FRIDAY AND
POSSIBLY LINGERING INTO SATURDAY AS SHOWN BY THE LATEST MEX
GUIDANCE. HOWEVER, THE ECMWF IS ALSO HOLDING ONTO ITS SLOWER
SOLUTION WITH THE CENTRAL PLAINS TROUGH PHASING WITH THE UPSTREAM
SYSTEM BUT FARTHER TO THE NORTH. IT THEN SHOWS THE FRONT STALLING
ACROSS CENTRAL FLORIDA SATURDAY AND SUNDAY SO THE HIGHEST POPS WOULD
BE OVER NEXT WEEKEND. AT THIS TIME, IT IS A WAIT AND SEE APPROACH
WITH LITTLE CHANGE TO THE CURRENT FORECAST.
MARINE...
WIND AND SEAS WILL REMAIN BELOW ADVISORY LEVELS THROUGH THE END OF
THIS WEEK WITH A LIGHT TO MODERATE EAST TO SOUTHEAST WIND AND SEAS
OF 5 FEET OR LESS. THE WIND WILL INCREASE AND BECOME MORE
SOUTHERLY BY FRIDAY AS A COLD FRONT MOVES INTO NORTH FLORIDA AND
THE HIGH PRESSURE SHIFTS FARTHER EAST INTO THE ATLANTIC.
FIRE WEATHER...
RELATIVE HUMIDITY WILL REMAIN WELL ABOVE CRITICAL THRESHOLDS
THROUGH THE END OF THIS WEEK AS LOW LEVEL MOISTURE WILL CONTINUE
TO INCREASE. THIS WILL ALSO INCREASE THE LIKELIHOOD FOR SOME LATE
NIGHT FOG FORMATION OVER THE INTERIOR AND SOUTHWEST COAST AS THE
WEEK PROGRESSES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 69 81 72 83 / 10 10 20 20
FORT LAUDERDALE 70 82 73 83 / 10 10 20 20
MIAMI 71 82 71 83 / 10 10 20 20
NAPLES 65 84 69 89 / - 10 10 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/DG
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1025 PM EDT TUE APR 9 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 100300Z IND TAF UPDATE/...
ISSUED AT 1025 PM EDT TUE APR 9 2013
VFR CONDITIONS SHOULD CONTINUE THROUGH THE NIGHT. WOULD NOT RULE OUT
A SHOWER OR THUNDERSTORM OVERNIGHT...BUT SO FAR ACTIVITY HAS BEEN ON
THE LIGHT AND ISOLATED SIDE IN THE LAF AREA. SO...WILL KEEP IT DRY
THROUGH 15Z.
PREVIOUS DISCUSSION FOLLOWS...
QUASI-STATIONARY WARM FRONT WILL LIE ACROSS NORTHERN INDIANA THROUGH
WEDNESDAY NIGHT AS THE ASSOCIATED SURFACE LOW MOVES ACROSS NORTHERN
MISSOURI AND INTO WEST CENTRAL ILLINOIS BY 00Z THURSDAY. AN UPPER
WAVE COULD BRING SOME SCATTERED STORMS TO NEAR LAF THIS EVENING
BUT CHANCES LOOK TOO LOW TO MENTION WITH NOTHING UPSTREAM. THE
RAPID REFRESH AND MOS LOOK OVERDONE IN DEVELOPING CONVECTION WITH
MOST OF THE ACTIVITY EXPECTED TO STAY CLOSER TO THE WARM FRONT. WILL
ADD VCTS AND CB TO ALL THE TERMINALS AFTER 12Z AS ADDITIONAL UPPER
WAVES MOVE ACROSS IN THE FAST SOUTHWEST FLOW ALOFT...35 KNOT LOW
LEVEL JET SPREADS SOUTHWEST TO NORTHEAST ACROSS CENTRAL INDIANA AND
DEW POINTS REACH THE 60S. FLYING CONDITIONS SHOULD ALSO DETERIORATE
TO MVFR AFTER 12Z WEDNESDAY.
THIS EVENING...BUFKIT SUGGESTS SOUTH AND SOUTHWEST WIND GUSTS WILL
DIE OFF BY 01Z ONLY TO RETURN TO NEAR 25 KNOTS AFTER 15Z TOMORROW.
AFTER COORDINATING WITH THE ZID CWSU...HELD LOW LEVEL WIND SHEAR
OUT TONIGHT AS IT APPEARS MARGINAL WITH LITTLE DIRECTIONAL SHEAR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...50
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...MK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
955 PM EDT TUE APR 9 2013
.UPDATE...
THE NEAR TERM 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 100000Z TAF ISSUANCE/...
ISSUED AT 645 PM EDT TUE APR 9 2013
QUASI-STATIONARY WARM FRONT WILL LIE ACROSS NORTHERN INDIANA THROUGH
WEDNESDAY NIGHT AS THE ASSOCIATED SURFACE LOW MOVES ACROSS NORTHERN
MISSOURI AND INTO WEST CENTRAL ILLINOIS BY 00Z THURSDAY. AN UPPER
WAVE COULD BRING SOME SCATTERED STORMS TO NEAR LAF THIS EVENING
BUT CHANCES LOOK TOO LOW TO MENTION WITH NOTHING UPSTREAM. THE
RAPID REFRESH AND MOS LOOK OVERDONE IN DEVELOPING CONVECTION WITH
MOST OF THE ACTIVITY EXPECTED TO STAY CLOSER TO THE WARM FRONT. WILL
ADD VCTS AND CB TO ALL THE TERMINALS AFTER 12Z AS ADDITIONAL UPPER
WAVES MOVE ACROSS IN THE FAST SOUTHWEST FLOW ALOFT...35 KNOT LOW
LEVEL JET SPREADS SOUTHWEST TO NORTHEAST ACROSS CENTRAL INDIANA AND
DEW POINTS REACH THE 60S. FLYING CONDITIONS SHOULD ALSO DETERIORATE
TO MVFR AFTER 12Z WEDNESDAY.
THIS EVENING...BUFKIT SUGGESTS SOUTH AND SOUTHWEST WIND GUSTS WILL
DIE OFF BY 01Z ONLY TO RETURN TO NEAR 25 KNOTS AFTER 15Z TOMORROW.
AFTER COORDINATING WITH THE ZID CWSU...HELD LOW LEVEL WIND SHEAR
OUT TONIGHT AS IT APPEARS MARGINAL WITH LITTLE DIRECTIONAL SHEAR.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...NIELD
NEAR TERM...50
SHORT TERM...NIELD
LONG TERM....SMF
AVIATION...MK
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1248 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 953 AM CDT MON APR 8 2013
MCV AND THE ASSOCIATED PRECIPITATION IS STARTING TO MOVE ACROSS
LAKE MICHIGAN AND THE DOWNWARD MOTION BEHIND THE MCV HAS ENDING
THE RAIN ACROSS THE AREA. A RESPECTABLE OUTFLOW BOUNDARY LIES JUST
SOUTH OF THE CWFA AND THERE IS A VORT MAX CROSSING THE MISSOURI RIVER.
THE QUESTION NOW IS WILL PRECIPITATION REGENERATE THIS AFTERNOON.
IF THE RAP FCST SOUNDING TRENDS ARE CORRECT...THE CONVECTIVE
TEMPERATURE WILL SLOWLY INCREASE THROUGH LATE MORNING AND
AFTERNOON AND SHOULD BE HIGHER THAN THE FCST MAX TEMPERATURES.
THUS THE OUTFLOW BOUNDARY SOUTH OF THE CWFA SHOULD REMAIN QUIET.
WITH CONVECTIVE TEMPERATURES HIGHER THAN THE FCST MAX...THE
INCOMING VORT MAX SHOULD ONLY RESULT IN SOME PASSING CLOUDS. ..08..
UPDATE ISSUED AT 659 AM CDT MON APR 8 2013
HAVE JUST SENT OUT A QUICK UPDATE TO FRESHEN UP THE FORECAST FOR
RECENT RADAR TRENDS...TEMPERATURES AND WINDS. BAND OF RAINFALL IS
STILL ON TRACK TO MOVE OUT OF THE FORECAST AREA BY MID TO LATE
MORNING...WITH NO ADDITIONAL THUNDER.
ALSO UPDATED AVIATION SECTION BELOW.
&&
.SYNOPSIS...
ISSUED AT 330 AM CDT MON APR 8 2013
A NICE MCS IS ONGOING OVER THE FORECAST AREA THIS MORNING...WITH
A 40-50KT LOW LEVEL JET IMPINGING ON THE SOUTHWEST FLANK OF THE
SYSTEM...IN AN AREA OF VERY GOOD MID LEVEL CONVERGENCE AND A WEAK
850MB FRONT...AND BETTER SURFACE FRONT. MOST OF THE THUNDERSTORMS
ARE MOVING ACROSS MISSOURI THIS MORNING...WITH A BROAD AREA OF
RAIN AND EMBEDDED THUNDER ROTATING NORTHEAST ACROSS THE FORECAST
AREA. THE MCV WITH THIS MCS IS WHAT IS DRIVING SOME OF THE
EAST-NORTHEAST MOVEMENT...AND EXPECT THAT NEARLY ALL OF THE
FORECAST AREA WILL RECEIVE RAINFALL BEFORE THE EVENT IS OVER. THE
BEST RAINFALL RATES HAVE RANGED UP TO 4 TENTHS OF AN INCH PER
HOUR...BUT MORE LOCATIONS ARE RECEIVING BETWEEN 1 AND 3
TENTHS/HOUR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT MON APR 8 2013
TODAY THE MAIN CONCERN IS FOR HOW QUICKLY THIS MCS WILL MOVE EAST
OUT OF THE FORECAST AREA THIS MORNING. THEN...HAVE CONCERNS FOR
POSSIBLE CONVECTION ALONG THE FRONT DURING THE DAYTIME. AN
THEN...OUR NEXT MCS IS EXPECTED TONIGHT AS THE NEXT SHORTWAVE
MOVES OUT ACROSS THE AREA AND INTERACTS WITH THE SURFACE WARM
FRONT DRAPED ACROSS THE AREA. IN ALL...THIS IS A RATHER DAMP
FORECAST.
TODAY HAVE USED MCS TECHNIQUES AND MODELS AS WELL AS NOWCASTING
TECHNIQUES INDICATE THIS MCS WILL MOVE OUT OF THE EASTERN PORTIONS
OF THE FORECAST AREA ABOUT 15Z. UNTIL THEN THOUGH...AM CARRYING
SOME VERY HIGH POPS FOR ABOUT THE SOUTHERN THREE QUARTERS OF THE
AREA. DO NOT EXPECT MUCH ADDITIONAL THUNDER DEVELOPMENT AS WE ARE
GETTING INTO THE TIME RANGE WHEN THE LOW LEVEL JET SHOULD START TO
WEAKEN. THERE MAY BE SOME LINGERING SHOWERS PAST 15Z...BUT HAVE
KEPT POPS PRETTY LOW FOR NOW.
THEN...WE SHOULD MANAGE TO BREAK OUT INTO AT LEAST A LITTLE
SUNSHINE AS THE CLOUDS WITH THE MCS ARE SWEPT EAST. THIS SHOULD
ALLOW TEMPERATURES TO RISE INTO THE 60S AND EVEN LOW TO MID
70S...MAINLY SOUTHWEST WHERE THE SUNSHINE BREAKS OUT SOONEST. THE
WARM FRONT WILL BE DRAPED FROM EAST TO WEST ACROSS THE FORECAST
AREA OVER ABOUT THE NORTHERN THIRD OF THE AREA BY AFTERNOON...AND
THE WARM AIR THAT SURGES INTO THE AREA ON THE SOUTH SIDE OF THE
BOUNDARY SHOULD HELP BOOST TEMPS AS WELL. THE MCS WILL HAVE LEFT
BEHIND AN OUTFLOW BOUNDARY WHICH MAY SERVE AS A FOCUS FOR
ADDITIONAL THUNDERSTORM DEVELOPMENT THIS AFTERNOON...AND AM
CARRYING SOME LOW CHANCE POPS FOR THEN.
TONIGHT THE NEXT SURGE OF WAA AND THETA-E ADVECTION SHOULD CAUSE
THUNDERSTORMS TO BEGIN DEVELOPING OVER THE AREA DURING THE
EVENING...AND GRADUALLY INCREASING IN COVERAGE OVERNIGHT. AS THERE
ARE NOT ANY INITIAL STRONG FEATURES TO PIN DOWN AND TIMING IS
SOMEWHAT PROBLEMATIC...HAVE PLACED HIGHEST POPS ALONG THE WARM
FRONT AND GONE SLIGHTLY LOWER TOWARDS THE SOUTH. THIS WILL NEED
SOME REFINEMENT AS FEATURES SET UP LATER TODAY. MIN TEMPS SHOULD
BE KEPT MILD BY THE WARM AIRMASS AND AT LEAST BROKEN CLOUD COVER.
MIN TEMPS ONLY EXPECTED TO FALL INTO THE 50S.
LE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 330 AM CDT MON APR 8 2013
FORECAST FOCUS ON MAJOR SLOW MOVING STORM SYSTEM THIS WEEK THEN
COLDER TEMPERATURES BEHIND THE SYSTEM. FORECAST BASED ON THE MORE
CONSISTENT ECMWF MODEL...THE GFS SEEMS A BIT TOO AGGRESSIVE WITH
MOVING THE DEEP TROUGH TO THE EAST TOO QUICKLY.
TUESDAY THROUGH WEDNESDAY...SEVERAL ROUNDS OF WIDESPREAD SHOWERS AND
THUNDERSTORMS AS DEEP WESTERN TROUGH PUSHES SLOWLY ACROSS THE
MIDWEST. FRONTAL BOUNDARY WILL BE LOCATED IN THE CWA ALONG WITH
CONTINUED EXCELLENT FEED OFF THE GULF. PRECIPITABLE WATER WILL BE
WELL OVER AN INCH WITH THE POTENTIAL FOR HEAVY RAIN AMOUNTS OF AT
LEAST 1 TO 3 INCHES DURING THIS TIME FRAME ESPECIALLY IF REPEATED
BOUTS OF THUNDERSTORMS TRAIN OVER THE SAME AREAS. WARM ON TUESDAY
WITH HIGHS IN THE 70S ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80.
WEDNESDAY IS THE DAY WHEN THE MAIN TROUGH/DYNAMICS ARRIVE WITH THE
HEAVIEST RAINS AND POSSIBLE SEVERE WEATHER. HOWEVER THIS WILL DEPEND
ON EXACT TRACK OF THE SURFACE LOW...TIMING OF THE STRONG COLD FRONT
AND AMOUNT OF INSTABILITY. AT THIS POINT SPC HAS A SLIGHT RISK FOR
SEVERE IN OUR SOUTHERN COUNTIES TUESDAY AND TUESDAY NIGHT WITH THE
MAIN THREAT OF SEVERE ON WEDNESDAY MAINLY EAST/SOUTH OF THE DVN
CWA.
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...COLDER AIR WILL BE FILTERING
INTO THE REGION AS THE DEEP TROUGH PUSHES EASTWARD. LOOKS COLD
ENOUGH FOR EITHER A RAIN/SNOW MIX OR ALL SNOW BUT MUCH OF THE
AVAILABLE MOISTURE WILL HAVE PUSHED EAST OF THE CWA BY THE TIME THE
COLD AIR ARRIVES. THEREFORE NOT EXPECTING ANY ACCUMULATION. LOOKS
DRY ON FRIDAY. HOWEVER...TEMPERATURES WILL BE BELOW NORMAL WITH
HIGHS MAINLY IN THE 40S WITH LOWS DIPPING INTO THE 20S AT SOME
LOCATIONS.
THIS WEEKEND/WEEK 2...THE 00Z ECMWF HAS BACKED OFF ON RAIN ARRIVING
LATER THIS WEEKEND AND NOW INDICATES DRY WEATHER ALONG WITH WARMING
TEMPERATURES. THIS AHEAD OF ANOTHER MAJOR TROUGH DIGGING INTO THE
WESTERN STATES. THIS FITS THE TELECONNECTIONS WITH THE AO/NAO GOING
NEUTRAL TO POSITIVE AND THE PNA GOING NEGATIVE. THIS FAVORS AN
ACTIVE STORM TRACK IN THE MIDDLE OF THE COUNTRY WITH DEEP TROUGHING
IN THE WEST AND RIDGING IN THE EAST. IF THE ECMWF IS CORRECT THEN IT
WILL BE DRY UNTIL NEXT TUESDAY WHEN A VIGOROUS NEGATIVE TILT TROUGH
AND DEEPENING SURFACE LOW ARRIVES FOLLOWED BY COOLER TEMPERATURES
AGAIN.
HAASE
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1245 PM CDT MON APR 8 2013
VFR WX WILL BE SEEN THROUGH 00Z/09 AT KCID/KMLI/KBRL. IFR
CONDITIONS AT KDBQ SHOULD GRADUALLY IMPROVE TO MVFR. AFT 00Z/09
ANOTHER THUNDERSTORM COMPLEX WILL DEVELOP ACROSS NORTHERN MISSOURI
AND THEN MOVE NORTH. ALL TAF SITES WILL BE IMPACTED WITH MVFR IF
NOT IFR CONDITIONS WITH PROBABLE TSRA. THE POTENTIAL DOES EXIST
FOR LIFR CONDITIONS BY SUNRISE TUESDAY. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...HAASE
AVIATION...08
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1002 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 953 AM CDT MON APR 8 2013
MCV AND THE ASSOCIATED PRECIPITATION IS STARTING TO MOVE ACROSS
LAKE MICHIGAN AND THE DOWNWARD MOTION BEHIND THE MCV HAS ENDING
THE RAIN ACROSS THE AREA. A RESPECTABLE OUTFLOW BOUNDARY LIES JUST
SOUTH OF THE CWFA AND THERE IS A VORT MAX CROSSING THE MISSOURI RIVER.
THE QUESTION NOW IS WILL PRECIPITATION REGENERATE THIS AFTERNOON.
IF THE RAP FCST SOUNDING TRENDS ARE CORRECT...THE CONVECTIVE
TEMPERATURE WILL SLOWLY INCREASE THROUGH LATE MORNING AND
AFTERNOON AND SHOULD BE HIGHER THAN THE FCST MAX TEMPERATURES.
THUS THE OUTFLOW BOUNDARY SOUTH OF THE CWFA SHOULD REMAIN QUIET.
WITH CONVECTIVE TEMPERATURES HIGHER THAN THE FCST MAX...THE
INCOMING VORT MAX SHOULD ONLY RESULT IN SOME PASSING CLOUDS. ..08..
UPDATE ISSUED AT 659 AM CDT MON APR 8 2013
HAVE JUST SENT OUT A QUICK UPDATE TO FRESHEN UP THE FORECAST FOR
RECENT RADAR TRENDS...TEMPERATURES AND WINDS. BAND OF RAINFALL IS
STILL ON TRACK TO MOVE OUT OF THE FORECAST AREA BY MID TO LATE
MORNING...WITH NO ADDITIONAL THUNDER.
ALSO UPDATED AVIATION SECTION BELOW.
&&
.SYNOPSIS...
ISSUED AT 330 AM CDT MON APR 8 2013
A NICE MCS IS ONGOING OVER THE FORECAST AREA THIS MORNING...WITH
A 40-50KT LOW LEVEL JET IMPINGING ON THE SOUTHWEST FLANK OF THE
SYSTEM...IN AN AREA OF VERY GOOD MID LEVEL CONVERGENCE AND A WEAK
850MB FRONT...AND BETTER SURFACE FRONT. MOST OF THE THUNDERSTORMS
ARE MOVING ACROSS MISSOURI THIS MORNING...WITH A BROAD AREA OF
RAIN AND EMBEDDED THUNDER ROTATING NORTHEAST ACROSS THE FORECAST
AREA. THE MCV WITH THIS MCS IS WHAT IS DRIVING SOME OF THE
EAST-NORTHEAST MOVEMENT...AND EXPECT THAT NEARLY ALL OF THE
FORECAST AREA WILL RECEIVE RAINFALL BEFORE THE EVENT IS OVER. THE
BEST RAINFALL RATES HAVE RANGED UP TO 4 TENTHS OF AN INCH PER
HOUR...BUT MORE LOCATIONS ARE RECEIVING BETWEEN 1 AND 3
TENTHS/HOUR.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 330 AM CDT MON APR 8 2013
TODAY THE MAIN CONCERN IS FOR HOW QUICKLY THIS MCS WILL MOVE EAST
OUT OF THE FORECAST AREA THIS MORNING. THEN...HAVE CONCERNS FOR
POSSIBLE CONVECTION ALONG THE FRONT DURING THE DAYTIME. AN
THEN...OUR NEXT MCS IS EXPECTED TONIGHT AS THE NEXT SHORTWAVE
MOVES OUT ACROSS THE AREA AND INTERACTS WITH THE SURFACE WARM
FRONT DRAPED ACROSS THE AREA. IN ALL...THIS IS A RATHER DAMP
FORECAST.
TODAY HAVE USED MCS TECHNIQUES AND MODELS AS WELL AS NOWCASTING
TECHNIQUES INDICATE THIS MCS WILL MOVE OUT OF THE EASTERN PORTIONS
OF THE FORECAST AREA ABOUT 15Z. UNTIL THEN THOUGH...AM CARRYING
SOME VERY HIGH POPS FOR ABOUT THE SOUTHERN THREE QUARTERS OF THE
AREA. DO NOT EXPECT MUCH ADDITIONAL THUNDER DEVELOPMENT AS WE ARE
GETTING INTO THE TIME RANGE WHEN THE LOW LEVEL JET SHOULD START TO
WEAKEN. THERE MAY BE SOME LINGERING SHOWERS PAST 15Z...BUT HAVE
KEPT POPS PRETTY LOW FOR NOW.
THEN...WE SHOULD MANAGE TO BREAK OUT INTO AT LEAST A LITTLE
SUNSHINE AS THE CLOUDS WITH THE MCS ARE SWEPT EAST. THIS SHOULD
ALLOW TEMPERATURES TO RISE INTO THE 60S AND EVEN LOW TO MID
70S...MAINLY SOUTHWEST WHERE THE SUNSHINE BREAKS OUT SOONEST. THE
WARM FRONT WILL BE DRAPED FROM EAST TO WEST ACROSS THE FORECAST
AREA OVER ABOUT THE NORTHERN THIRD OF THE AREA BY AFTERNOON...AND
THE WARM AIR THAT SURGES INTO THE AREA ON THE SOUTH SIDE OF THE
BOUNDARY SHOULD HELP BOOST TEMPS AS WELL. THE MCS WILL HAVE LEFT
BEHIND AN OUTFLOW BOUNDARY WHICH MAY SERVE AS A FOCUS FOR
ADDITIONAL THUNDERSTORM DEVELOPMENT THIS AFTERNOON...AND AM
CARRYING SOME LOW CHANCE POPS FOR THEN.
TONIGHT THE NEXT SURGE OF WAA AND THETA-E ADVECTION SHOULD CAUSE
THUNDERSTORMS TO BEGIN DEVELOPING OVER THE AREA DURING THE
EVENING...AND GRADUALLY INCREASING IN COVERAGE OVERNIGHT. AS THERE
ARE NOT ANY INITIAL STRONG FEATURES TO PIN DOWN AND TIMING IS
SOMEWHAT PROBLEMATIC...HAVE PLACED HIGHEST POPS ALONG THE WARM
FRONT AND GONE SLIGHTLY LOWER TOWARDS THE SOUTH. THIS WILL NEED
SOME REFINEMENT AS FEATURES SET UP LATER TODAY. MIN TEMPS SHOULD
BE KEPT MILD BY THE WARM AIRMASS AND AT LEAST BROKEN CLOUD COVER.
MIN TEMPS ONLY EXPECTED TO FALL INTO THE 50S.
LE
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 330 AM CDT MON APR 8 2013
FORECAST FOCUS ON MAJOR SLOW MOVING STORM SYSTEM THIS WEEK THEN
COLDER TEMPERATURES BEHIND THE SYSTEM. FORECAST BASED ON THE MORE
CONSISTENT ECMWF MODEL...THE GFS SEEMS A BIT TOO AGGRESSIVE WITH
MOVING THE DEEP TROUGH TO THE EAST TOO QUICKLY.
TUESDAY THROUGH WEDNESDAY...SEVERAL ROUNDS OF WIDESPREAD SHOWERS AND
THUNDERSTORMS AS DEEP WESTERN TROUGH PUSHES SLOWLY ACROSS THE
MIDWEST. FRONTAL BOUNDARY WILL BE LOCATED IN THE CWA ALONG WITH
CONTINUED EXCELLENT FEED OFF THE GULF. PRECIPITABLE WATER WILL BE
WELL OVER AN INCH WITH THE POTENTIAL FOR HEAVY RAIN AMOUNTS OF AT
LEAST 1 TO 3 INCHES DURING THIS TIME FRAME ESPECIALLY IF REPEATED
BOUTS OF THUNDERSTORMS TRAIN OVER THE SAME AREAS. WARM ON TUESDAY
WITH HIGHS IN THE 70S ESPECIALLY ALONG AND SOUTH OF INTERSTATE 80.
WEDNESDAY IS THE DAY WHEN THE MAIN TROUGH/DYNAMICS ARRIVE WITH THE
HEAVIEST RAINS AND POSSIBLE SEVERE WEATHER. HOWEVER THIS WILL DEPEND
ON EXACT TRACK OF THE SURFACE LOW...TIMING OF THE STRONG COLD FRONT
AND AMOUNT OF INSTABILITY. AT THIS POINT SPC HAS A SLIGHT RISK FOR
SEVERE IN OUR SOUTHERN COUNTIES TUESDAY AND TUESDAY NIGHT WITH THE
MAIN THREAT OF SEVERE ON WEDNESDAY MAINLY EAST/SOUTH OF THE DVN
CWA.
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...COLDER AIR WILL BE FILTERING
INTO THE REGION AS THE DEEP TROUGH PUSHES EASTWARD. LOOKS COLD
ENOUGH FOR EITHER A RAIN/SNOW MIX OR ALL SNOW BUT MUCH OF THE
AVAILABLE MOISTURE WILL HAVE PUSHED EAST OF THE CWA BY THE TIME THE
COLD AIR ARRIVES. THEREFORE NOT EXPECTING ANY ACCUMULATION. LOOKS
DRY ON FRIDAY. HOWEVER...TEMPERATURES WILL BE BELOW NORMAL WITH
HIGHS MAINLY IN THE 40S WITH LOWS DIPPING INTO THE 20S AT SOME
LOCATIONS.
THIS WEEKEND/WEEK 2...THE 00Z ECMWF HAS BACKED OFF ON RAIN ARRIVING
LATER THIS WEEKEND AND NOW INDICATES DRY WEATHER ALONG WITH WARMING
TEMPERATURES. THIS AHEAD OF ANOTHER MAJOR TROUGH DIGGING INTO THE
WESTERN STATES. THIS FITS THE TELECONNECTIONS WITH THE AO/NAO GOING
NEUTRAL TO POSITIVE AND THE PNA GOING NEGATIVE. THIS FAVORS AN
ACTIVE STORM TRACK IN THE MIDDLE OF THE COUNTRY WITH DEEP TROUGHING
IN THE WEST AND RIDGING IN THE EAST. IF THE ECMWF IS CORRECT THEN IT
WILL BE DRY UNTIL NEXT TUESDAY WHEN A VIGOROUS NEGATIVE TILT TROUGH
AND DEEPENING SURFACE LOW ARRIVES FOLLOWED BY COOLER TEMPERATURES
AGAIN.
HAASE
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 659 AM CDT MON APR 8 2013
BAND OF RAINFALL CURRENTLY AFFECTING KCID AND KMLI WITH MVFR CIGS
AND LIFR CIGS AT KDBQ WILL GRADUALLY IMPROVE THIS MORNING AS THE
BAND OF RAIN MOVES EAST. SOME FOG POSSIBLE AT KCID NEXT FEW HOURS. KCID
TO IMPROVE TO VFR FIRST...FOLLOWED BY KDBQ AND KMLI BY NO LATER
THAN 16Z. CONDITIONS SHOULD REMAIN VFR THROUGH THE REST OF TODAY
AND INTO AT LEAST THE EARLY PART OF TONIGHT. SHOWERS AND
THUNDERSTORMS TO REDEVELOP AFTER 03Z TONIGHT...BRINGING AT LEAST
IFR CONDITIONS FOR BOTH CIGS AND VSBYS...BECOMING MORE WIDESPREAD
AFTER 06Z AND POSSIBLY LOWERING TO LIFR. HAVE LEFT LIFR CONDITIONS
OUT OF FORECAST FOR NOW DUE TO TIMING UNCERTAINTIES. LE
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...LE
SHORT TERM...LE
LONG TERM...HAASE
AVIATION...LE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
326 PM CDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
19Z WATER VAPOR IMAGERY SHOWS AN UPPER LOW DIGGING SOUTHEAST INTO
SOUTHERN NV AND AZ. AT THE SURFACE A WEAK BOUNDARY NOTED MORE IN THE
DEWPOINT FIELD HAS LIFTED INTO SOUTHERN NEB.
TONIGHT WITH THE UPPER LOW ACROSS THE SOUTHWEST...THE FORECAST AREA
SHOULD REMAIN MAINLY UNDER SHORTWAVE RIDGING ALOFT WITH SOUTHERLY
RETURN FLOW PERSISTING. THIS LOW LEVEL FLOW IS EXPECTED TO ADVECT AN
ELEVATED MIXED LAYER OR CAPPING INVERSION NORTH INTO NEB AND THE
LATEST RAP SOUNDINGS SUPPORT THIS IDEA WITH A STRENGTHENING
INVERSION EARLY THIS EVENING ALONG THE NEB STATE LINE. SO AM
THINKING THAT ELEVATED STORMS ARE MORE LIKELY TO OCCUR OVER SOUTHERN
NEB WHERE ISENTROPIC UPGLIDE INTERACTS WITH THE WEAK BOUNDARY. SOME
OF THE LATEST HI RES MODELS ARE SHOWING A SIMILAR IDEA. STORMS THAT
FORM IN NORTH KS MAY STILL HAVE THE POTENTIAL FOR LARGE HAIL GIVEN
STEEP MID LEVEL LAPSE RATES. WITH CONTINUED SOUTHERLY FLOW AND
MOISTURE ADVECTION INTO THE AREA...A STRATUS DECK IS EXPECTED TO
REDEVELOP THIS EVENING. THE CLOUD COVER COMBINED WITH A WARM MOIST
BOUNDARY LAYER SHOULD CREATE A VERY MILD NIGHT WITH LOWS ONLY IN THE
LOWER 60S.
BY TUESDAY...THE MODELS HAVE TRENDED A LITTLE SLOWER WITH THE
FRONTAL PASSAGE AND ONLY BEGIN TO BRING IT INTO THE NORTH CENTRAL
COUNTIES BY LATE AFTERNOON. WITH THE SUBSTANTIAL CAPPING INVERSION
IN THE WARM SECTOR...THINK THAT DEEP MOIST CONVECTION WILL LIKELY
HOLD OFF UNTIL THE FRONT MOVES THROUGH TO LIFT SURFACE PARCELS TO
THE LFC. WITH THE LINEAR FORCING FOR CONVECTION...THUNDERSTORMS MAY
QUICKLY DEVELOP INTO A SQUALL LINE WITH STRONG WINDS AND HAIL THE
MOST LIKELY HAZARD. SO THE FORECAST SHOWS POPS INCREASING LATE IN
THE AFTERNOON ACROSS NORTH CENTRAL KS. SINCE THERE IS NO REAL COLD
AIR ADVECTION TO SPEAK OF THROUGH THE DAY...HIGHS SHOULD AGAIN BE
MILD WITH UPPER 60S TO 70S FROM NORTH CENTRAL KS TO EAST CENTRAL KS.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 252 PM CDT MON APR 8 2013
FOR THE MOST PART THE MAIN SQUALL LINE APPEARS POISED TO MOVE
ACROSS THE FORECAST AREA BETWEEN 00Z AND 06Z DURING THE EVENING
HOURS ON TUESDAY. WARM NOSE AROUND 775MB WILL INHIBIT CONVECTION
IN THE WARM SECTOR AND THINK MOST LOCATIONS WILL NOT SEE ACTIVITY
UNTIL THE FORCING WITH THE FRONT BREAKS THROUGH. MAY HAVE ONGOING
CONVECTION ALONG AND NORTH OF THE WARM FRONT ACROSS NORTHERN
KANSAS AT THE BEGINNING OF THE PERIOD AS WELL. 0-6KM WIND SHEAR
VECTORS GENERALLY 50-60KTS BUT DIRECTIONAL TURNING IS NOT AS
IMPRESSIVE. GIVEN INSTABILITY GENERALLY 800-1200J/KG THINK THAT
MAIN CONCERN WILL BE WINDS WITH THE STORMS AS THE LINE PASSES.
SOME LOCALLY HEAVY RAIN ALSO POSSIBLE AND CANNOT RULE OUT ISOLATED
TORNADOES ALONG THE LINE...BUT AT THIS TIME IS NOT THE PRIMARY
CONCERN. TRAILING RAIN AND ISOLATED T CONTINUE THROUGH THE NIGHT.
NEXT CONCERN IS COLD AIR DIVING SOUTHWARD BEHIND THIS SYSTEM. WARM
NOSE IS INITIALLY SO WARM THINK THAT PRECIP WILL STAY AS RAIN
DESPITE COOLING SURFACE TEMPERATURES...BUT AS THIS NOSE COOLS
THEN MORE COMPLEX PRECIP TYPES COME INTO PLAY. BY THE TIME IT GETS
COLD ENOUGH ALOFT FOR SNOW...THE MOISTURE AND LIFT ARE GENERALLY
EAST OF THE AREA. AS THE COLD AIR AT THE SURFACE GETS COLDER...THE
CHANCE FOR A CHANGEOVER TO SLEET OR FREEZING RAIN ALSO INCREASES.
HAVE STARTED WITH A RAIN SNOW MIX ACROSS THE NORTHWEST...BUT THINK
THIS WILL BE MORE OF A MIXED BAG...WITH LITTLE OF IT STICKING TO
THE GROUND AND ANY ACCUMULATION ON ELEVATED SURFACES. INITIAL
CHANCES FOR MIXED PRECIP ARE NORTH AND WEST OF MANHATTAN AFTER
MIDNIGHT INTO WEDNESDAY MORNING...RETREATING SOMEWHAT BACK INTO
NORTH CENTRAL KANSAS WEDNESDAY AFTERNOON. THE CHANCES THEN SPREAD
EASTWARD WITH A MIX POSSIBLE WEDNESDAY NIGHT INTO THURSDAY MORNING
ACROSS MUCH OF NORTHEAST AND EAST CENTRAL KANSAS. WILL HAVE TO
MONITOR FORECAST SOUNDINGS OVER NEXT FEW RUNS...BUT A QUICK ROUND
OF SOME TYPE OF FREEZING PRECIP LOOKS POSSIBLE FOR NORTH CENTRAL
KANSAS.
THE AIRMASS THAT DROPS INTO THE PLAINS BEHIND THE FRONT HOLDS
HIGHS IN THE 30S AND 40S WEDNESDAY...40S FOR THURSDAY...SLOWLY
RISING TOWARD 50 ON FRIDAY AND BACK TOWARD NORMAL LATER IN THE
WEEKEND. OVERNIGHT LOW TEMPERATURES MAY FALL BELOW FREEZING
WEDNESDAY NIGHT THROUGH FRIDAY NIGHT...FINALLY RISING BACK INTO
THE 40S SATURDAY NIGHT. ALTHOUGH THE GROWING SEASON IS SLOW TO
START...ITS WORTH NOTING THAT EARLY EMERGENT VEGETATION WILL SEE
COLD OVERNIGHT LOWS MID TO LATE WEEK. 67
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1226 PM CDT MON APR 8 2013
THE TERMINALS SHOULD REMAIN WITHIN THE WARM MOIST SECTOR THROUGH
18Z WED WITH THE MODELS SHOWING AN EML EVENTUALLY ADVECTING OVER
THE AREA CAPPING THE BOUNDARY LAYER. SOME OF THE HIGH RES MODELS
SUGGEST THERE COULD BE SOME ISOLATED CONVECTION THIS AFTERNOON.
THINK THIS ACTIVITY IS MORE LIKELY TO THE NORTH OF THE TERMINALS
SO WILL NOT INCLUDE A MENTION. CIGS SHOULD IMPROVE ABOVE 3 KFT
THIS AFTERNOON ONLY TO COME BACK DOWN BELOW 2 KFT OVERNIGHT. MOS
GUIDANCE IS AGAIN HITTING IFR CIGS. CONFIDENCE IS MARGINAL THAT
IFR CIGS WILL MOVE IN...SO HAVE KEPT CIGS JUST ABOVE 1 KFT FOR
NOW.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...WOLTERS
AREA FORECAST DISCUSSION
NWS WICHITA KS
324 PM CDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 322 PM CDT MON APR 8 2013
THE MAIN FORECAST CONCERNS ARE THE SEVERE WEATHER CHANCES TONIGHT
AND TOMORROW AND WINTRY PRECIPITATION BEHIND THE COLD FRONT TUESDAY
NIGHT/WEDNESDAY.
A LARGE POTENT UPPER TROUGH IS DIGGING INTO THE INTERIOR MOUNTAIN
WEST THIS AFTERNOON WITH A WEAK WAVE MOVING NORTHEAST OVER THE GREAT
LAKES. THE DEEP TROUGH WILL BE THE WEATHER MAKER FOR THE NEXT FEW
DAYS. MOSTLY CLOUDY SKIES COVER MUCH OF KANSAS EXCEPT EXTREME
WESTERN AND SOUTHWESTERN SECTIONS. TEMPERATURES ARE WARM...IN THE
LOW 70S AND WINDS ARE BREEZY BETWEEN 10 AND 20 MPH.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
THIS PERIOD IS THE ONE TO WATCH IN TERMS OF SEVERE WEATHER CHANCES.
THE POTENT UPPER LEVEL DISTURBANCE IS SLOWLY MAKING ITS WAY EASTWARD
WITH WEAK DIFFLUENCE OVER THE CENTRAL PLAINS. SOUTHERN KANSAS IS IN
THE WARM SECTOR AND LOW LEVEL INHIBITION (CIN) IS HIGH. THE RUC AND
NAM DO SHOW AN AREA OVER EXTREME NORTH CENTRAL OKLAHOMA WHERE CIN
DECREASES LATE THIS AFTERNOON/EARLY EVENING WHERE A THUNDERSTORM
COULD DEVELOP. CONFIDENCE IS NOT OVERLY HIGH THAT MUCH OF SOUTH
CENTRAL KANSAS WILL SEE A STORM...BUT AREAS WEST OF HIGHWAY 14 COULD
SEE A THUNDERSTORM BEFORE DARK THIS EVENING.
BEYOND THIS TONIGHT...THE MAIN FOCUS WILL BE OVER THE HIGH
PLAINS AND CENTRAL KANSAS NORTH OF I-70 WHERE CIN WILL BE ABLE TO
ERODE QUICKER BEFORE THE NOCTURNAL BOUNDARY LAYER TAKES HOLD. THESE
STORMS HAVE THE CHANCE OF BEING SEVERE WITH MODEST 1000-1500 J/KG
CAPE AND 40-55 KTS 0-6KM BULK SHEAR. THIS AREA WILL TRANSLATE
EASTWARD AND MOVE INTO CENTRAL KANSAS. THE BEST CHANCES FOR
PRECIPITATION OVERNIGHT WILL BE ALONG AND NORTH OF I-70.
THINGS CHANGE TUESDAY WITH THE VERY STRONG COLD FRONT BEGINNING TO
GAIN ITS MOMENTUM TUESDAY MORNING AS THE UPPER TROUGH MOVES INTO THE
AREA. THE POTENT FRONT WILL APPROACH CENTRAL KANSAS BY AFTERNOON.
AS THE FRONT REACHES CENTRAL AND EASTERN KANSAS...IT WILL BE ABLE TO
TAP MOIST BOUNDARY LAYER AIR...AND THE CAP WILL ERODE ALONG AND
NEAR THE FRONT IN THE AFTERNOON HOURS. A FEW DISCRETE STORMS MAY BE
ABLE TO DEVELOP EARLY...BUT WITH THE LARGE AMOUNT OF LINEAR FORCING
WITH THE FRONT A SQUALL LINE IS EXPECTED TO BECOME THE MAIN
CONVECTIVE MODE. THE STORMS ARE EXPECTED TO FIRE NEAR THE
I-135/I-35 CORRIDOR AND MOVE EASTWARD FROM THERE DURING THE EVENING
AND OVERNIGHT HOURS. THE MAIN THREATS ARE LARGE HAIL AND DAMAGING
WINDS WITH THE LINEAR CONVECTIVE MODE...BUT CANNOT RULE OUT A
TORNADO EARLY.
OUTSIDE OF THE SEVERE THUNDERSTORM CHANCES...THE OTHER MAIN CONCERN
IS TEMPERATURES BEHIND THE FRONT. THIS FRONT IS BEING FORCED SOUTH
BY COLD ARCTIC AIR. THIS WILL CAUSE TEMPERATURES TO DROP
DRASTICALLY ONCE THE FRONT MOVES THROUGH. USED THE NAM...FEELING IT
HAS THE BEST RESOLUTION AS A NON-DIURNAL TREND OVERNIGHT TONIGHT
THROUGH TOMORROW NIGHT.
BILLINGS
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 322 PM CDT MON APR 8 2013
TUESDAY NIGHT - WEDNESDAY:
COLD TEMPERATURES BEHIND THE FRONT WILL BRING A SHOCK TO OUR
SYSTEMS...AS PRECIPITATION ON THE BACK SIDE OF THE UPPER LOW COULD
FALL AS A WINTRY MIX TUESDAY NIGHT AND EARLY WEDNESDAY IN CENTRAL
KANSAS. CONFIDENCE IN PRECIP TYPE IS LOW GIVEN LOW LEVEL PROFILES.
WILL ALLOW NEXT COUPLE SHIFTS TO FINE TUNE THESE CHANCES. BY
WEDNESDAY DAYTIME HIGH TEMPERATURES WILL BE WELL BELOW NORMAL...IN
THE UPPER 30S AND LOW 40S.
THURSDAY - SATURDAY:
BY THURSDAY THINGS DRY OUT WITH THE UPPER WAVE MAKING ITS WAY OVER
THE PLAINS...WITH SUBSIDENCE AND SURFACE HIGH PRESSURE BUILDING IN
BEHIND THE FRONT. THE ARCTIC AIR WILL HOLD ON AND TEMPS WILL
STRUGGLE TO WARM INTO THE 50S ON THURSDAY AND FRIDAY. BY SATURDAY
HIGH PRESSURE WILL MOVE SOUTHEAST AND SOUTHERLY FLOW WILL RETURN
HELPING TEMPERATURES TO IMPROVE BACK TO NEAR NORMAL IN THE LOW 60S.
SUNDAY - MONDAY:
ANOTHER WAVE WILL IMPACT THE REGION LATE IN THE WEEKEND AND EARLY
NEXT WEEK...BUT THE GUIDANCE IS OUT OF PHASE WITH THE SOLUTIONS.
THE GFS IS PULLING A FRONT THROUGH MUCH QUICKER THAN THE ECMWF.
CONFIDENCE ON THIS FEATURE IS LOW AND WENT WITH MODEL CONSENSUS.
BILLINGS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1237 PM CDT MON APR 8 2013
STRATOCU AND STRATUS CIGS WILL CONTINUE TO PLAGUE THE ENTIRE AREA
THROUGH THE FORECAST VALID PERIOD...WITH PRIMARILY MVFR DURING THE
AFTERNOON AND EARLY EVENING LOWERING TO IFR CIGS/VSBYS TONIGHT
INTO TUESDAY MORNING. CONVECTION IS EXPECTED TO DEVELOP ACROSS THE
HIGH PLAINS LATE THIS AFTERNOON AND EARLY EVENING...WHICH COULD
MOVE INTO PORTIONS OF CENTRAL KANSAS OVERNIGHT. A STRONG COLD
FRONT WILL IMPACT THE AREA JUST BEYOND THE FORECAST VALID PERIOD
WITH STRONG TO SEVERE CONVECTION EXPECTED TO AFFECT THE AREA ON
TUESDAY AFTERNOON AND EVENING.
KED
&&
.FIRE WEATHER...
ISSUED AT 322 PM CDT MON APR 8 2013
FIRE WEATHER CONCERNS ARE LOW DURING THE NEXT COUPLE OF DAYS ARE
LOW...BUT BY WEDNESDAY STRONG WINDS BEHIND THE COLD FRONT WILL CAUSE
GRASSLAND FIRE DANGER TO BE VERY HIGH ACROSS MUCH OF CENTRAL AND
SOUTH CENTRAL KANSAS.
BILLINGS
&&
.PRELIMINARY POINT TEMPS/POPS...
WICHITA-KICT 64 72 34 43 / 20 60 60 40
HUTCHINSON 63 72 29 41 / 20 60 40 30
NEWTON 63 69 30 39 / 20 60 60 40
ELDORADO 63 73 35 43 / 10 60 60 40
WINFIELD-KWLD 64 74 36 44 / 10 60 60 40
RUSSELL 60 65 22 38 / 40 50 40 10
GREAT BEND 61 67 24 39 / 30 50 40 10
SALINA 63 70 31 41 / 30 60 50 30
MCPHERSON 63 69 30 40 / 20 60 50 30
COFFEYVILLE 64 75 45 46 / 10 40 70 50
CHANUTE 63 73 44 45 / 10 50 70 50
IOLA 63 73 44 45 / 10 50 70 50
PARSONS-KPPF 64 75 44 45 / 10 50 70 50
&&
.ICT WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1226 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1028 AM CDT MON APR 8 2013
12Z UPPER AIR ANALYSIS INDICATED THE EML HAS YET TO ADVECT INTO
NORTHEAST KS WITH THE WARMER 700 MB TEMPS STILL ACROSS OK. THE RAP
AND NAM INDICATE THE WARM AIR ADVECTION PATTERN AND WEAK
ISENTROPIC LIFT WILL PERSIST THROUGH THE DAY. WITH THE CAP NOT AS
STRONG AS EARLIER ANTICIPATED...HAVE PUT A SLIGHT CHANCE FOR
SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST FOR THIS
AFTERNOON ACROSS NORTH CENTRAL AND NORTHEAST KS THINKING THERE
COULD BE SOME POPCORN CONVECTION ON THE NORTHERN EDGE OF THE EML.
THE RAP AND HRRR ARE SHOWING THIS POTENTIAL AND AGITATED CU FIELD
ACROSS CENTRAL KS SHOWS THERE IS SOME ELEVATED INSTABILITY TO WORK
WITH.
UPDATE ISSUED AT 642 AM CDT MON APR 8 2013
WEAK ISENTROPIC LIFT MAY CAUSE A FEW ISOLATED SHOWERS ALONG THE
WESTERN AND SOUTHERN COUNTIES OF THE CWA THIS MORNING. ONCE THE
BOUNDARY LAYER MIXES ABOVE 925MB THESE WEAK RAIN SHOWERS SHOULD
DISSIPATE AROUND 10 AM. PATCHY GROUND FOG WAS DEVELOPING AROUND
THE CWA...SO I HAVE INCLUDED PATCHY FOG IN THE FORECAST THROUGH 10
AM.
UPDATED THE AVIATION DISCUSSION AS WELL.
GARGAN
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT MON APR 8 2013
TODAY...AN INTENSE UPPER LEVEL TROUGH WILL DIG SOUTHEAST FROM OR AND
NORTHERN CA INTO NV AND NORTHERN AZ BY LATE THIS AFTERNOON. A LEE
SURFACE LOW WILL DEEPEN OVER SOUTHEAST CO...CAUSING SURFACE AND
850MB WINDS TO BACK TO THE SOUTHEAST ACROSS MUCH OF KS. THE STRONGER
WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL KS DURING THE
AFTERNOON HOURS WITH WINDS INCREASING TO NEAR 30 MPH WITH GUSTS TO
40 MPH. WINDS ACROSS THE CWA WILL INCREASE TO 15 TO 25 MPH WITH
GUSTS OF 30 MPH ACROSS NORTH CENTRAL KS DURING THE AFTERNOON HOURS.
A SURFACE DRYLINE WILL PUNCH NORTHEAST INTO EXTREME SOUTHWEST KS
DURING THE AFTERNOON HOURS AND THEN ARC NORTHWEST INTO NORTHEAST CO.
SURFACE CONVERGENCE AHEAD OF THE DRYLINE...ALONG WITH ASCENT AHEAD
OF THE H5 TROUGH MOVING INTO NORTHERN AZ...WILL CAUSE THUNDERSTORMS
TO DEVELOP DURING THE AFTERNOON HOURS ACROSS WESTERN KS AND
NORTHEAST CO. VERTICAL WIND SHEAR PROFILES AND SUFFICIENT
INSTABILITY WILL ALLOW FOR SOME SEVERE THUNDERSTORMS TO DEVELOP
ACROSS WESTERN KS AND NORTHEAST CO. THOUGH...IF THE CLOUD COVER
HOLDS THROUGH THE DAY ACROSS WESTERN KS THEN THE INSTABILITY MAY NOT
BE SUFFICIENT FOR SEVERE THUNDERSTORMS. A COMPLEX OF STRONG TO
SEVERE STORMS MAY MOVE INTO NORTH CENTRAL KS TONIGHT.
ACROSS EASTERN KS...A COMBINATION OF BOTH THE DOWN STREAM H5 RIDGE
AMPLIFYING AND AN EML SPREADING NORTHEAST ACROSS THE CWA WILL CREATE
A STRONG CAPPING INVERSION. THE CAPPING INVERSION SHOULD PREVENT ANY
SURFACE BASED THUNDERSTORMS FROM DEVELOPING. THERE MAY
BE SOME ISOLATED SHOWERS SOUTH OF I-70 DURING THE DAY DUE TO THE
INCREASING DEEP MOISTURE ADVECTION...BUT AT THIS TIME THE MOIST
PARCELS SHOULD NOT BE FORCED TO THEIR LEVEL OF FREE CONVECTION
ABOVE THE CAPPING INVERSION. THEREFORE...I ONLY WENT WITH 14 POPS
DURING THE DAY.
THE STRATUS CLOUD COVER MAY HOLD IN FOR MOST OF THE DAY BUT IF THERE
ARE SOME BREAKS IN THE CLOUD COVER THIS AFTERNOON HIGH TEMPERATURES
MAY REACH THE MID 70S...BUT IN AREAS WHERE THE CLOUD COVER HOLDS
HIGHS MAY ONLY REACH AROUND 70 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 344 AM CDT MON APR 8 2013
TONIGHT...THE BEST CHANCES FOR THUNDERSTORMS TONIGHT WILL BE ACROSS
THE NORTHERN CWA FROM LATER THIS EVENING THROUGH THE OVERNIGHT HOURS
AS CONVECTION THAT DEVELOPS IN THE HIGH PLAINS/NORTHWEST KS
SPREADS/DEVELOPS EASTWARD...ALTHOUGH THE OVERALL AREA OF CONVECTION
APPEARS WILL BE EVEN FURTHER NORTH AND WEST THAN PREVIOUS TRENDS
WITH FORECAST INHIBITION EVEN MORE PRONOUNCED SOUTH AND EAST. HAVE
THEREFORE LOWERED POPS ACROSS THE EAST CENTRAL NOT ONLY FOR TONIGHT
BUT ALSO FOR TUESDAY MORNING AS HIGHER QPF REMAINS WELL NORTH AND
WEST CLOSER TO THE FRONT.
AS THE PRIMARY SHORTWAVE TROUGH ROTATES OUT OF THE ROCKIES AND INTO
THE NORTHERN HIGH PLAINS...THE COLD FRONT WILL SURGE EASTWARD
THROUGH THE DAY...MOVING THROUGH MUCH OF THE NORTH CENTRAL COUNTIES
IN THE MORNING AND TO NEAR THE TURNPIKE BY LATE AFTERNOON BEFORE
CLEARING THE REMAINDER OF THE EASTERN COUNTIES THROUGH THE EVENING.
MUCH OF THE EARLY DAY CONVECTION WILL LIKELY OCCUR ALONG AND JUST
BEHIND THE FRONT BEFORE SHIFTING SOUTH AND EAST WITH THE FRONT INTO
THE EVENING HOURS OVER THE EAST CENTRAL COUNTIES AS LARGE SCALE
ASCENT SPREADS NORTH AND EASTWARD ALONG AND JUST BEHIND THE FRONT
LATER IN THE AFTERNOON AND EVENING. ALTHOUGH SHEAR WILL REMAIN
STRONG AHEAD OF FRONT...THE STRONG CAPPING INVERSION WILL ALSO
REMAIN IN PLACE. WHEN COMBINED WITH THE FASTER FROPA...CLOUD COVER
AND EXTENSIVE PRECIP...THE OVERALL INSTABILITY AND SEVERE WEATHER
POTENTIAL IS HARDER TO PINPOINT. ALTHOUGH STRONG CONVECTION WILL BE
POSSIBLE ALONG THE FRONT THROUGH THE DAY...THE MOST ACTIVE PERIOD
APPEARS WILL SETUP ACROSS NORTHEAST AND EAST CENTRAL KS IN THE
MID/LATE AFTERNOON AS THE FRONT PUSHES THROUGH AS THE MAIN SHORTWAVE
TROUGH LIFTS OUT INTO THE PLAINS. SCATTERED STRONG TO SEVERE
THUNDERSTORMS MAY FORM A SQUALL LINE INTO THE EVENING AS IT PUSHES
EASTWARD. THIS SHOULD ALSO BE THE TIME OF THE HEAVIER PRECIP ACROSS
THE SOUTHEAST COUNTIES. AS COLDER AIR WORKS SOUTH AND EAST INTO THE
CWA LATE TUESDAY NIGHT AND INTO WED...A RAIN/SNOW MIX IS POSSIBLE
ACROSS THE WESTERN 1/3 OF THE CWA...THEN POSSIBLY OVER THE REMAINDER
OF THE NORTH/NORTHEAST CORNER WEDNESDAY NIGHT/EARLY THU MORNING. AT
THIS TIME...ONLY LIGHT SNOWFALL AMOUNTS...IF ANY...ARE EXPECTED
ACROSS THE FAR NORTHWEST COUNTIES. HOWEVER...IF THE SYSTEM OR DRY
SLOT MOVES OUT FURTHER SOUTH AND EAST THAN FORECAST...MORE IN THE
WAY OF ACCUMULATING SNOW WOULD BE POSSIBLE IN THE NORTH CENTRAL AND
BORDER COUNTIES ALONG THE NORTHERN BORDER.
EITHER WAY...IT SHOULD BE DRY ACROSS THE CWA BY THU AFTERNOON INTO
FRIDAY BEFORE ANOTHER CHANCE FOR SHOWERS RETURNS TO THE AREA OVER
THE WEEKEND AS WARM AIR ADVECTION INCREASES AHEAD OF ANOTHER
SHORTWAVE TROUGH. HIGHS IN THE 40S ON THURSDAY SHOULD WARM BACK INTO
THE 60S AND 70S FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1226 PM CDT MON APR 8 2013
THE TERMINALS SHOULD REMAIN WITHIN THE WARM MOIST SECTOR THROUGH
18Z WED WITH THE MODELS SHOWING AN EML EVENTUALLY ADVECTING OVER
THE AREA CAPPING THE BOUNDARY LAYER. SOME OF THE HIGH RES MODELS
SUGGEST THERE COULD BE SOME ISOLATED CONVECTION THIS AFTERNOON.
THINK THIS ACTIVITY IS MORE LIKELY TO THE NORTH OF THE TERMINALS
SO WILL NOT INCLUDE A MENTION. CIGS SHOULD IMPROVE ABOVE 3 KFT
THIS AFTERNOON ONLY TO COME BACK DOWN BELOW 2 KFT OVERNIGHT. MOS
GUIDANCE IS AGAIN HITTING IFR CIGS. CONFIDENCE IS MARGINAL THAT
IFR CIGS WILL MOVE IN...SO HAVE KEPT CIGS JUST ABOVE 1 KFT FOR
NOW.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WOLTERS
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...WOLTERS
AREA FORECAST DISCUSSION...UPDATED
NWS TOPEKA KS
1028 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1028 AM CDT MON APR 8 2013
12Z UPPER AIR ANALYSIS INDICATED THE EML HAS YET TO ADVECT INTO
NORTHEAST KS WITH THE WARMER 700 MB TEMPS STILL ACROSS OK. THE RAP
AND NAM INDICATE THE WARM AIR ADVECTION PATTERN AND WEAK
ISENTROPIC LIFT WILL PERSIST THROUGH THE DAY. WITH THE CAP NOT AS
STRONG AS EARLIER ANTICIPATED...HAVE PUT A SLIGHT CHANCE FOR
SHOWERS AND THUNDERSTORMS BACK INTO THE FORECAST FOR THIS
AFTERNOON ACROSS NORTH CENTRAL AND NORTHEAST KS THINKING THERE
COULD BE SOME POPCORN CONVECTION ON THE NORTHERN EDGE OF THE EML.
THE RAP AND HRRR ARE SHOWING THIS POTENTIAL AND AGITATED CU FIELD
ACROSS CENTRAL KS SHOWS THERE IS SOME ELEVATED INSTABILITY TO WORK
WITH.
UPDATE ISSUED AT 642 AM CDT MON APR 8 2013
WEAK ISENTROPIC LIFT MAY CAUSE A FEW ISOLATED SHOWERS ALONG THE
WESTERN AND SOUTHERN COUNTIES OF THE CWA THIS MORNING. ONCE THE
BOUNDARY LAYER MIXES ABOVE 925MB THESE WEAK RAIN SHOWERS SHOULD
DISSIPATE AROUND 10 AM. PATCHY GROUND FOG WAS DEVELOPING AROUND
THE CWA...SO I HAVE INCLUDED PATCHY FOG IN THE FORECAST THROUGH 10
AM.
UPDATED THE AVIATION DISCUSSION AS WELL.
GARGAN
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 344 AM CDT MON APR 8 2013
TODAY...AN INTENSE UPPER LEVEL TROUGH WILL DIG SOUTHEAST FROM OR AND
NORTHERN CA INTO NV AND NORTHERN AZ BY LATE THIS AFTERNOON. A LEE
SURFACE LOW WILL DEEPEN OVER SOUTHEAST CO...CAUSING SURFACE AND
850MB WINDS TO BACK TO THE SOUTHEAST ACROSS MUCH OF KS. THE STRONGER
WINDS WILL DEVELOP ACROSS WESTERN AND CENTRAL KS DURING THE
AFTERNOON HOURS WITH WINDS INCREASING TO NEAR 30 MPH WITH GUSTS TO
40 MPH. WINDS ACROSS THE CWA WILL INCREASE TO 15 TO 25 MPH WITH
GUSTS OF 30 MPH ACROSS NORTH CENTRAL KS DURING THE AFTERNOON HOURS.
A SURFACE DRYLINE WILL PUNCH NORTHEAST INTO EXTREME SOUTHWEST KS
DURING THE AFTERNOON HOURS AND THEN ARC NORTHWEST INTO NORTHEAST CO.
SURFACE CONVERGENCE AHEAD OF THE DRYLINE...ALONG WITH ASCENT AHEAD
OF THE H5 TROUGH MOVING INTO NORTHERN AZ...WILL CAUSE THUNDERSTORMS
TO DEVELOP DURING THE AFTERNOON HOURS ACROSS WESTERN KS AND
NORTHEAST CO. VERTICAL WIND SHEAR PROFILES AND SUFFICIENT
INSTABILITY WILL ALLOW FOR SOME SEVERE THUNDERSTORMS TO DEVELOP
ACROSS WESTERN KS AND NORTHEAST CO. THOUGH...IF THE CLOUD COVER
HOLDS THROUGH THE DAY ACROSS WESTERN KS THEN THE INSTABILITY MAY NOT
BE SUFFICIENT FOR SEVERE THUNDERSTORMS. A COMPLEX OF STRONG TO
SEVERE STORMS MAY MOVE INTO NORTH CENTRAL KS TONIGHT.
ACROSS EASTERN KS...A COMBINATION OF BOTH THE DOWN STREAM H5 RIDGE
AMPLIFYING AND AN EML SPREADING NORTHEAST ACROSS THE CWA WILL CREATE
A STRONG CAPPING INVERSION. THE CAPPING INVERSION SHOULD PREVENT ANY
SURFACE BASED THUNDERSTORMS FROM DEVELOPING. THERE MAY
BE SOME ISOLATED SHOWERS SOUTH OF I-70 DURING THE DAY DUE TO THE
INCREASING DEEP MOISTURE ADVECTION...BUT AT THIS TIME THE MOIST
PARCELS SHOULD NOT BE FORCED TO THEIR LEVEL OF FREE CONVECTION
ABOVE THE CAPPING INVERSION. THEREFORE...I ONLY WENT WITH 14 POPS
DURING THE DAY.
THE STRATUS CLOUD COVER MAY HOLD IN FOR MOST OF THE DAY BUT IF THERE
ARE SOME BREAKS IN THE CLOUD COVER THIS AFTERNOON HIGH TEMPERATURES
MAY REACH THE MID 70S...BUT IN AREAS WHERE THE CLOUD COVER HOLDS
HIGHS MAY ONLY REACH AROUND 70 DEGREES.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 344 AM CDT MON APR 8 2013
TONIGHT...THE BEST CHANCES FOR THUNDERSTORMS TONIGHT WILL BE ACROSS
THE NORTHERN CWA FROM LATER THIS EVENING THROUGH THE OVERNIGHT HOURS
AS CONVECTION THAT DEVELOPS IN THE HIGH PLAINS/NORTHWEST KS
SPREADS/DEVELOPS EASTWARD...ALTHOUGH THE OVERALL AREA OF CONVECTION
APPEARS WILL BE EVEN FURTHER NORTH AND WEST THAN PREVIOUS TRENDS
WITH FORECAST INHIBITION EVEN MORE PRONOUNCED SOUTH AND EAST. HAVE
THEREFORE LOWERED POPS ACROSS THE EAST CENTRAL NOT ONLY FOR TONIGHT
BUT ALSO FOR TUESDAY MORNING AS HIGHER QPF REMAINS WELL NORTH AND
WEST CLOSER TO THE FRONT.
AS THE PRIMARY SHORTWAVE TROUGH ROTATES OUT OF THE ROCKIES AND INTO
THE NORTHERN HIGH PLAINS...THE COLD FRONT WILL SURGE EASTWARD
THROUGH THE DAY...MOVING THROUGH MUCH OF THE NORTH CENTRAL COUNTIES
IN THE MORNING AND TO NEAR THE TURNPIKE BY LATE AFTERNOON BEFORE
CLEARING THE REMAINDER OF THE EASTERN COUNTIES THROUGH THE EVENING.
MUCH OF THE EARLY DAY CONVECTION WILL LIKELY OCCUR ALONG AND JUST
BEHIND THE FRONT BEFORE SHIFTING SOUTH AND EAST WITH THE FRONT INTO
THE EVENING HOURS OVER THE EAST CENTRAL COUNTIES AS LARGE SCALE
ASCENT SPREADS NORTH AND EASTWARD ALONG AND JUST BEHIND THE FRONT
LATER IN THE AFTERNOON AND EVENING. ALTHOUGH SHEAR WILL REMAIN
STRONG AHEAD OF FRONT...THE STRONG CAPPING INVERSION WILL ALSO
REMAIN IN PLACE. WHEN COMBINED WITH THE FASTER FROPA...CLOUD COVER
AND EXTENSIVE PRECIP...THE OVERALL INSTABILITY AND SEVERE WEATHER
POTENTIAL IS HARDER TO PINPOINT. ALTHOUGH STRONG CONVECTION WILL BE
POSSIBLE ALONG THE FRONT THROUGH THE DAY...THE MOST ACTIVE PERIOD
APPEARS WILL SETUP ACROSS NORTHEAST AND EAST CENTRAL KS IN THE
MID/LATE AFTERNOON AS THE FRONT PUSHES THROUGH AS THE MAIN SHORTWAVE
TROUGH LIFTS OUT INTO THE PLAINS. SCATTERED STRONG TO SEVERE
THUNDERSTORMS MAY FORM A SQUALL LINE INTO THE EVENING AS IT PUSHES
EASTWARD. THIS SHOULD ALSO BE THE TIME OF THE HEAVIER PRECIP ACROSS
THE SOUTHEAST COUNTIES. AS COLDER AIR WORKS SOUTH AND EAST INTO THE
CWA LATE TUESDAY NIGHT AND INTO WED...A RAIN/SNOW MIX IS POSSIBLE
ACROSS THE WESTERN 1/3 OF THE CWA...THEN POSSIBLY OVER THE REMAINDER
OF THE NORTH/NORTHEAST CORNER WEDNESDAY NIGHT/EARLY THU MORNING. AT
THIS TIME...ONLY LIGHT SNOWFALL AMOUNTS...IF ANY...ARE EXPECTED
ACROSS THE FAR NORTHWEST COUNTIES. HOWEVER...IF THE SYSTEM OR DRY
SLOT MOVES OUT FURTHER SOUTH AND EAST THAN FORECAST...MORE IN THE
WAY OF ACCUMULATING SNOW WOULD BE POSSIBLE IN THE NORTH CENTRAL AND
BORDER COUNTIES ALONG THE NORTHERN BORDER.
EITHER WAY...IT SHOULD BE DRY ACROSS THE CWA BY THU AFTERNOON INTO
FRIDAY BEFORE ANOTHER CHANCE FOR SHOWERS RETURNS TO THE AREA OVER
THE WEEKEND AS WARM AIR ADVECTION INCREASES AHEAD OF ANOTHER
SHORTWAVE TROUGH. HIGHS IN THE 40S ON THURSDAY SHOULD WARM BACK INTO
THE 60S AND 70S FOR THE WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 642 AM CDT MON APR 8 2013
IN AREAS WHERE THE STRATUS HAS CLEARED...PATCHY GROUND FOG HAS
FORMED. VISIBILITIES WERE AS LOW AS ONE HALF AT KTOP. THE GROUND
FOG SHOULD DISSIPATE AROUND 15Z. THE MVFR STRATUS SHOULD REFORM
WITH CEILINGS OF 1800 TO 2500 FT...AS DEEPER MOISTURE ADVECTS
NORTHWARD. I CANNOT RULE OUT AN ISOLATED SHOWER THROUGH THE
MORNING HOURS. MHK MAY SEE AN INCREASING CHANCE FOR THUNDERSTORMS
DURING THE EARLY MORNING HOURS OF TUESDAY.
GARGAN
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WOLTERS
SHORT TERM...GARGAN
LONG TERM...63
AVIATION...GARGAN
AREA FORECAST DISCUSSION...CORRECTED
NWS GOODLAND KS
359 AM MDT MON APR 8 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 357 AM MDT MON APR 8 2013
UNSETTLED/ACTIVE PATTERN EXPECTED THROUGH WED AS STRONG UPPER LOW
DEVELOPS OVER FOUR CORNERS REGION TODAY AND MOVES ACROSS PLAINS
THROUGH MIDWEEK.
DENSE FOG HAS DEVELOPED EARLY THIS MORNING ACROSS EASTERN PARTS OF
THE CWA. WITH TD VALUES ONLY EXPECTED TO INCREASE IN THE EAST IT IS
REASONABLE TO ASSUME THESE CONDITIONS WILL CONTINUE. RUC/NAM SUPPORT
THIS...SHOWING LOW VISIBILITIES THROUGH 14-15Z TIME-FRAME ACROSS
EASTERN LOCATIONS. I WENT AHEAD AND ISSUED AN DENSE FOG ADVISORY FOR
THE EASTERN TIER OF THE CWA THROUGH 15Z...AND MAY HAVE TO EXPAND
FURTHER BASED ON TRENDS.
THIS AFTERNOON/EVENING...PRIMARY CONCERN CONTINUES TO BE POTENTIAL
FOR SEVERE THUNDERSTORMS ACROSS THE CWA WITH GOOD INSTABILITY AND
VERY STRONG SHEER THIS AFTERNOON/EVENING. MAIN QUESTION IS
WHERE INITIATION WILL OCCUR DURING DAY TODAY AND COVERAGE. LARGE
SCALE FORCING SHOULD STILL BE WELL TO THE WEST TODAY WITH H3 JET
STREAK NOT IN FAVORABLE LOCATION UNTIL LATER TONIGHT. WITH THIS IN
MIND...SURFACE CONVERGENCE ALONG FRONT/DRY LINE AND SURFACE TROUGH
SHOULD ACT AS MAIN FOCUS FOR INITIATION THIS AFTERNOON/EVENING. I
ADJUSTED TIMING COVERAGE THIS AFTERNOON WITH BETTER CHANCES AFTER
00Z. WITH LOW STRATUS POSSIBLY OVERSPREADING CWA AND LINGERING
THIS MORNING...WE COULD SEE A DELAY IN INITIATION AND MUCH LESS
SURFACE BASED CAPE IN THE EAST. SOUNDING ANALYSIS WOULD STILL
SUPPORT ELEVATED INSTABILITY IF THIS WERE TO OCCUR...SO I KEPT
MENTION IN PLACE FOR NOW...THOUGH THIS IS STILL A CONCERN. WITH
THE ADVERTISED SHEER PROFILES...IF ANYTHING DOES INITIATE AND
MOVE INTO OUR CWA LATE THIS AFTERNOON/EVENING THERE IS AN INCREASED
LIKELIHOOD IT WILL BECOME SUPERCELLULAR WITH VERY LARGE HAIL AND
TORNADOES POSSIBLE.
TONIGHT-WEDNESDAY...INSTABILITY AXIS QUICKLY SHIFTS EAST LATE THIS
EVENING...AS VERY STRONG COLD FRONT MOVES IN FROM NORTH. STRONG
FORCING AND GOOD MOISTURE ADVECTION SHOULD OVERSPREAD THE CWA LATE
TONIGHT ACROSS WESTERN LOCATIONS. THE RESULT SHOULD BE DIMINISHED
CHANCES FOR THUNDERSTORMS BY 06Z...WHILE THE OVERALL PRECIP COVERAGE
INCREASES. AN UNSEASONABLY COLD AIRMASS WILL OVERSPREAD THE CWA
FROM THE NW TO SE THROUGH TUESDAY MORNING WITH RAIN TRANSITIONING
TO EITHER SNOW OR FREEZING RAIN/DRIZZLE. SOUNDINGS ARE VERY CLOSE
IN RESPECT TO SNOW OR FREEZING PRECIP...AND DEPENDING ON MODEL
CHOICE ONE OR THE OTHER WILL BE THE DOMINATE PRECIP TYPE DURING
THE DAY TUESDAY. THIS IS A CONCERN IF WE END UP WITH MAINLY
FREEZING RAIN/DRIZZLE AND MAY NEED TO ISSUE ADVISORY ACCORDINGLY
FOR MUCH OF CWA. THIS WOULD ALSO RESULT IN LESS SNOW THAN
CURRENTLY ADVERTISED FOR NW LOCATIONS. BY TUESDAY NIGHT ALL PRECIP
SHOULD BE SNOW...THOUGH BULK OF LIFT/MOISTURE WILL BE
TRANSITIONING NORTH AND EAST OF THE AREA...SO WE PROBABLY WONT BE
SEEING MUCH IN THE WAY OF ADDITIONAL SNOW AFTER TUESDAY EVENING.
REGARDING WINTER STORM WATCH...THERE IS TOO MUCH UNCERTAINTY TO
EXPAND OR CANCEL AT THIS POINT. THERE IS STILL POTENTIAL FOR 3-6"
SNOW TOTALS IN NW YUMA COUNTY IF THEY SEE PRIMARILY SNOW DURING THE
DAY TUESDAY AND TRACK REMAINS FAVORABLE. I AM NOT CONFIDENT ENOUGH
TO UPGRADE AT THIS POINT TO WARNING OR ADVISORY...WITH SOME GUIDANCE
SHOWING MAIN SNOW BAND FURTHER WEST AND NORTH. I THINK WE WILL
PROBABLY NEED AN ADVISORY OF SOME SORT WITH POTENTIAL FOR STRONG
WINDS/BLOWING SNOW/FREEZING DRIZZLE/LIGHT SNOW ACROSS THE
NORTHWEST HALF OF THE CWA. THERE ARE JUST TOO MANY QUESTIONS RIGHT
NOW TO ZERO IN ON HOW THIS WILL EVOLVE...AND WHAT FLAVOR OF HAZARD
WE WILL NEED.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 233 AM MDT MON APR 8 2013
SOME DISAGREEMENT AND UNCERTAINTY THROUGH THIS PERIOD...ESPECIALLY
EARLY ON. IN GENERAL...DETERMINISTIC AND ENSEMBLE OUTPUT SUPPORT
A ZONAL OR NEARLY ZONAL FLOW THROUGH THIS PERIOD WITH MANY SMALL
SCALE SHORTWAVE TROUGHS MOVING THROUGH. MODELS HAVING TROUBLE
RESOLVING WHAT IS GOING TO HAPPEN IN THE SHORT TERM AND THAT HAS
AFFECTS INTO THIS PERIOD. MODELS DISAGREE ON THE FLOW ALOFT AND
SHORTWAVES IN THIS FLOW THROUGH THIS PERIOD. THE CRH_INIT HAS
GIVEN ME SOME SLIGHT CHANCE POPS THURSDAY NIGHT AND ONCE AGAIN
FROM FRIDAY NIGHT INTO SATURDAY MORNING. GIVEN THE PROBLEMS
DISCUSSED ABOVE AND SINCE ONLY SLIGHT CHANCE WILL NOT MAKE ANY
CHANGES TO THESE GRIDS. OTHERWISE LOOKS DRY FOR THE REST OF THE
PERIOD.
LEFT REMAINING GRIDS ALONE AS WELL. LOOKS LIKE A WARMING TREND
OCCURS THROUGH THIS PERIOD AND THIS LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE
INITIATION...BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME
SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ003-004-
015-016-029.
CO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ090.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
358 AM MDT MON APR 8 2013
.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)
ISSUED AT 357 AM MDT MON APR 8 2013
UNSETTLED/ACTIVE PATTERN EXPECTED THROUGH WED AS STRONG UPPER LOW
DEVELOPS OVER FOUR CORNERS REGION TODAY AND MOVES ACROSS PLAINS
THROUGH MIDWEEK.
DENSE FOG HAS DEVELOPED EARLY THIS MORNING ACROSS EASTERN PARTS OF
THE CWA. WITH TD VALUES ONLY EXPECTED TO INCREASE IN THE EAST IT IS
REASONABLE TO ASSUME THESE CONDITIONS WILL CONTINUE. RUC/NAM SUPPORT
THIS...SHOWING LOW VISIBILITIES THROUGH 14-15Z TIME-FRAME ACROSS
EASTERN LOCATIONS. I WENT AHEAD AND ISSUED AN DENSE FOG ADVISORY FOR
THE EASTERN TIER OF THE CWA THROUGH 15Z...AND MAY HAVE TO EXPAND
FURTHER BASED ON TRENDS.
THIS AFTERNOON/EVENING...PRIMARY CONCERN CONTINUES TO BE POTENTIAL
FOR SEVERE THUNDERSTORMS ACROSS THE CWA WITH GOOD INSTABILITY AND
VERY STRONG SHEER THIS AFTERNOON/EVENING. MAIN QUESTION IS
WHERE INITIATION WILL OCCUR DURING DAY TODAY AND COVERAGE. LARGE
SCALE FORCING SHOULD STILL BE WELL TO THE WEST TODAY WITH H3 JET
STREAK NOT IN FAVORABLE LOCATION UNTIL LATER TONIGHT. WITH THIS IN
MIND...SURFACE CONVERGENCE ALONG FRONT/DRY LINE AND SURFACE TROUGH
SHOULD ACT AS MAIN FOCUS FOR INITIATION THIS AFTERNOON/EVENING. I
ADJUSTED TIMING COVERAGE THIS AFTERNOON WITH BETTER CHANCES AFTER
00Z. WITH LOW STRATUS POSSIBLY OVERSPREADING CWA AND LINGERING
THIS MORNING...WE COULD SEE A DELAY IN INITIATION AND MUCH LESS
SURFACE BASED CAPE IN THE EAST. SOUNDING ANALYSIS WOULD STILL
SUPPORT ELEVATED INSTABILITY IF THIS WERE TO OCCUR...SO I KEPT
MENTION IN PLACE FOR NOW...THOUGH THIS IS STILL A CONCERN. WITH
THE ADVERTISED SHEER PROFILES...IF ANYTHING DOES INITIATE AND
MOVE INTO OUR CWA LATE THIS AFTERNOON/EVENING THERE IS AN INCREASED
LIKELIHOOD IT WILL BECOME SUPERCELLULAR WITH VERY LARGE HAIL AND
TORNADOES POSSIBLE.
TONIGHT-WEDNESDAY...INSTABILITY AXIS QUICKLY SHIFTS EAST LATE THIS
EVENING...AS VERY STRONG COLD FRONT MOVES IN FROM NORTH. STRONG
FORCING AND GOOD MOISTURE ADVECTION SHOULD OVERSPREAD THE CWA LATE
TONIGHT ACROSS WESTERN LOCATIONS. THE RESULT SHOULD BE DIMINISHED
CHANCES FOR THUNDERSTORMS BY 06Z...WHILE THE OVERALL PRECIP COVERAGE
INCREASES. AN UNSEASONABLY COLD AIRMASS WILL OVERSPREAD THE CWA
FROM THE NW TO SE THROUGH TUESDAY MORNING WITH RAIN TRANSITIONING
TO EITHER SNOW OR FREEZING RAIN/DRIZZLE. SOUNDINGS ARE VERY CLOSE
IN RESPECT TO SNOW OR FREEZING PRECIP...AND DEPENDING ON MODEL
CHOICE ONE OR THE OTHER WILL BE THE DOMINATE PRECIP TYPE DURING
THE DAY TUESDAY. THIS IS A CONCERN IF WE END UP WITH MAINLY
FREEZING RAIN/DRIZZLE AND MAY NEED TO ISSUE ADVISORY ACCORDINGLY
FOR MUCH OF CWA. THIS WOULD ALSO RESULT IN LESS SNOW THAN
CURRENTLY ADVERTISED FOR NW LOCATIONS. BY TUESDAY NIGHT ALL PRECIP
SHOULD BE SNOW...THOUGH BULK OF LIFT/MOISTURE WILL BE
TRANSITIONING NORTH AND EAST OF THE AREA...SO WE PROBABLY WONT BE
SEEING MUCH IN THE WAY OF ADDITIONAL SNOW AFTER TUESDAY EVENING.
REGARDING WINTER STORM WATCH...THERE IS TOO MUCH UNCERTAINTY TO
EXPAND OR CANCEL AT THIS POINT. THERE IS STILL POTENTIAL FOR 3-6"
SNOW TOTALS IN NW YUMA COUNTY IF THEY SEE PRIMARILY SNOW DURING THE
DAY TUESDAY AND TRACK REMAINS FAVORABLE. I AM NOT CONFIDENT ENOUGH
TO UPGRADE AT THIS POINT TO WARNING OR ADVISORY...WITH SOME GUIDANCE
SHOWING MAIN SNOW BAND FURTHER WEST AND NORTH. I THINK WE WILL
PROBABLY NEED AN ADVISORY OF SOME SORT WITH POTENTIAL FOR STRONG
WINDS/BLOWING SNOW/FREEZING DRIZZLE/LIGHT SNOW ALL POSSIBLE ACROSS
THE NORTHWEST HALF OF THE CWA. THERE ARE JUST TOO MANY QUESTIONS
RIGHT NOW TO ZERO IN ON HOW THIS WILL EVOLVE...AND WHAT FLAVOR OF
HAZARD WE WILL NEED.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 233 AM MDT MON APR 8 2013
SOME DISAGREEMENT AND UNCERTAINTY THROUGH THIS PERIOD...ESPECIALLY
EARLY ON. IN GENERAL...DETERMINISTIC AND ENSEMBLE OUTPUT SUPPORT
A ZONAL OR NEARLY ZONAL FLOW THROUGH THIS PERIOD WITH MANY SMALL
SCALE SHORTWAVE TROUGHS MOVING THROUGH. MODELS HAVING TROUBLE
RESOLVING WHAT IS GOING TO HAPPEN IN THE SHORT TERM AND THAT HAS
AFFECTS INTO THIS PERIOD. MODELS DISAGREE ON THE FLOW ALOFT AND
SHORTWAVES IN THIS FLOW THROUGH THIS PERIOD. THE CRH_INIT HAS
GIVEN ME SOME SLIGHT CHANCE POPS THURSDAY NIGHT AND ONCE AGAIN
FROM FRIDAY NIGHT INTO SATURDAY MORNING. GIVEN THE PROBLEMS
DISCUSSED ABOVE AND SINCE ONLY SLIGHT CHANCE WILL NOT MAKE ANY
CHANGES TO THESE GRIDS. OTHERWISE LOOKS DRY FOR THE REST OF THE
PERIOD.
LEFT REMAINING GRIDS ALONE AS WELL. LOOKS LIKE A WARMING TREND
OCCURS THROUGH THIS PERIOD AND THIS LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE
INITIATION...BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME
SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR KSZ003-004-
015-016-029.
CO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ090.
NE...DENSE FOG ADVISORY UNTIL 10 AM CDT THIS MORNING FOR NEZ081.
&&
$$
SHORT TERM...DR
LONG TERM...BULLER
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GOODLAND KS
243 AM MDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 233 PM MDT SUN APR 7 2013
LATER THIS AFTERNOON MODELS CONTINUE TO INDICATE MUCAPE AROUND
500J/KG OR SO JUST EAST OF A SURFACE TROUGH EAST OF A GOVE TO HILL
CITY LINE. 0-6KM SHEAR OF 40 KTS WILL BE FAVORABLE FOR STRONG/SEVERE
STORMS TO DEVELOP...HOWEVER THERE WILL BE SOME SUBSIDENCE
INTERSPERCED WITH LIFT BEHIND THE EXITING SHORT WAVE TROUGH. IF
SEVERE THUNDERSTORMS DO DEVELOP...AM ANTICIPATING THEM TO BE ONLY
ISOLATED WITH HAIL UP TO QUARTER SIZE AND GUSTY OUTFLOW WINDS. THE
STRONG/SEVERE ACTIVITY SHOULD QUICKLY DIMINISH DURING THE EARLY
EVENING AS THE ENVIRONMENT BECOMES MORE STABLE.
TONIGHT SOME LINGERING LIFT BEHIND THE UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE INTO THE AREA THIS EVENING FROM THE WEST...WITH SOME LIFT
OVER THE FAR EASTERN PART OF THE AREA AS WELL. THE LIFT WILL MOVE
THROUGH THE AREA AND WEAKEN DURING THE LATE EVENING. DUE TO THE DRY
ENVIRONMENT BELOW 700MB OR SO...AND SUBTLE NATURE OF THE LIFT WILL
ONLY HAVE SLIGHT CHANCES FOR PRECIP. OVERNIGHT SUBSIDENCE AND DRIER
AIR MOVE INTO THE AREA BRINGING ANY PRECIP. TO AN END.
MONDAY AM ANTICIPATING ELEVATED THUNDERSTORMS TO BEGIN OVER EAST
CENTRAL COLORADO DURING THE EARLY AFTERNOON AS LIFT FROM A SHORT
WAVE TROUGH OVERSPREADS THE AREA. SOUNDINGS DURING THE EARLY
AFTERNOON REMAIN FAIRLY DRY UNTIL MOISTURE ADVECTION INCREASES WITH
STRENGTHENING LOW LEVEL JET DURING THE MID AND LATE AFTERNOON...SO
HAVE SLOWED HOW QUICKLY PRECIP. CHANCES INCREASE DURING THE
AFTERNOON. A WARM FRONT WILL MOVE INTO THE AREA DURING THE LATE
MORNING AND AFTERNOON. MODELS GENERALLY PLACE THE WARM FRONT BETWEEN
HWY 24 AND THE NEBRASKA BORDER. THE POSITION OF THE DRY LINE IS A
BIT HARDER TO PLACE...WITH MODELS EITHER KEEPING IT ALONG THE KS/CO
BORDER OR FURTHER EAST INTO WEST CENTRAL/SOUTHWEST KANSAS. THE
SREF/ECMWF/GFS GENERALLY PLACE IT ALONG THE KS/CO BORDER...SO WILL
SIDE WITH THEM. THIS PLACES THE INTERSECTION OF THE DRY LINE/WARM
FRONT NEAR THE CENTRAL PART OF THE TRI-STATE AREA. AM THINKING THE
STRONGER STORMS SHOULD BEGIN TO INITIATE TOWARD EARLY/MID AFTERNOON
NEAR THE INTERSECTION AS THE MOISTURE ADVECTION INCREASES
INSTABILITY. NAM POINT SOUNDINGS SHOW SLIGHTLY MORE INSTABILITY
ALONG THE DRY LINE THAN THE WARM FRONT. IN ADDITION MORE LIFT WILL
BE ALONG THE DRY LINE THAN THE WARM FRONT...SO AM THINKING STORMS SHOULD
FIRE ALONG THE DRY LINE FIRST THEN THE WARM FRONT. AS THE AFTERNOON
PROGRESSES THE WARM FRONT WILL ARK TO THE NORTHWEST...CAUSING THE
ENVIRONMENT TO BECOME MORE UNSTABLE OVER THE NORTHERN PART OF THE
AREA. THUNDERSTORM COVERAGE WILL INCREASE DURING THE MID TO LATE
AFTERNOON AS CAPE AND SYNOPTIC LIFT INCREASE OVER THE AREA.
DURING THE LATE AFTERNOON THE ENVIRONMENT SOUTH AND EAST OF HWY 40
BECOMES INCREASINGLY FAVORABLE FOR TON ADO DEVELOPMENT WITH 0-1KM
BULK SHEAR AROUND 15KTS AND EHI OF 3.5M2/S2. THE LARGE HAIL THREAT
LOOKS VERY GOOD...ESPECIALLY DURING THE MID TO LATE AFTERNOON AS THE
CAPE PROFILE IN THE HAIL GROWTH ZONE INCREASES AND MUCAPE NEARS
2000-3000J/KG.
.LONG TERM...(THURSDAY THROUGH SUNDAY)
ISSUED AT 233 AM MDT MON APR 8 2013
SOME DISAGREEMENT AND UNCERTAINTY THROUGH THIS PERIOD...ESPECIALLY EARLY
ON. IN GENERAL...DETERMINISTIC AND ENSEMBLE OUTPUT SUPPORT A ZONAL OR
NEARLY ZONAL FLOW THROUGH THIS PERIOD WITH MANY SMALL SCALE SHORTWAVE
TROUGHS MOVING THROUGH. MODELS HAVING TROUBLE RESOLVING WHAT IS GOING
TO HAPPEN IN THE SHORT TERM AND THAT HAS AFFECTS INTO THIS PERIOD.
MODELS DISAGREE ON THE FLOW ALOFT AND SHORTWAVES IN THIS FLOW
THROUGH THIS PERIOD. THE CRH_INIT HAS GIVEN ME SOME SLIGHT CHANCE
POPS THURSDAY NIGHT AND ONCE AGAIN FROM FRIDAY NIGHT INTO SATURDAY
MORNING. GIVEN THE PROBLEMS DISCUSSED ABOVE AND SINCE ONLY SLIGHT
CHANCE WILL NOT MAKE ANY CHANGES TO THESE GRIDS. OTHERWISE LOOKS
DRY FOR THE REST OF THE PERIOD.
LEFT REMAINING GRIDS ALONE AS WELL. LOOKS LIKE A WARMING TREND
OCCURS THROUGH THIS PERIOD AND THIS LOOKS REASONABLE.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE INITIATION...
BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
FOR COZ090.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...BULLER
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS TOPEKA KS
116 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 110 AM CDT MON APR 8 2013
THE TAIL END OF A LINE OF STORMS HAS MOVED EAST OUT OF THE CWA. A
FEW SHOWERS MAY DEVELOP NORTH OF AN OUTFLOW BOUNDARY THAT EXTENDS
FROM NEAR EUDORA...SOUTHWEST TO CARBONDALE. HOWEVER AS 925MB TO
850MB WINDS CONTINUE TO VEER THE ISENTROPIC LIFT NORTH OF THIS
BOUNDARY WILL WEAKEN AFTER 9Z. UPDATED ZONES TO REDUCE POPS TO
AREAS OF EAST CENTRAL KS SOUTH OF THE KS TURNPIKE...AND THEN
REDUCED POPS TO OR BELOW 14 PERCENT AFTER 9Z.
GARGAN
UPDATE ISSUED AT 959 PM CDT SUN APR 7 2013
UPDATED POPS/WX TO REFLECT THE LATEST RADAR TRENDS WITH THIS
EVENING`S THUNDERSTORM ACTIVITY. THUNDERSTORMS HAVE BEEN STEADILY
WEAKENING OVER THE LAST HOUR AND DIMINISHING IN COVERAGE ACROSS THE
FORECAST AREA. AS OF 03Z...THE LAST BAND OF THUNDERSTORMS WAS
TRACKING EAST ACROSS NORTHEASTERN KANSAS...HOWEVER A FEW ISOLATED
THUNDERSTORMS MAY STILL DEVELOP ACROSS EAST CENTRAL KANSAS THROUGH
LATE THIS EVENING. THESE LINGERING THUNDERSTORMS ARE ANTICIPATED TO
PROGRESS EAST OF THE CWA BY AROUND 06Z. AS A RESULT...HAVE TRENDED
WITH LOWERING POPS FROM WEST TO EAST ACROSS THE CWA THROUGH THE
REMAINDER OF THIS EVENING INTO THE EARLY OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
19Z WATER VAPOR IMAGERY SHOWS A QUASI-ZONAL FLOW ACROSS THE PLAINS
WITH A LOW AMPLITUDE SHORTWAVE MOVING ACROSS THE CO AND NM ROCKIES.
AT THE SURFACE A TROUGH OF LOW PRESSURE IN THE LEE OF THE ROCKIES
HAS STRENGTHENED AND CAUSED SOUTH AND SOUTHEAST WINDS TO INCREASE
BRINGING BETTER MOISTURE NORTH INTO SOUTHERN AND EASTERN KS.
THE UPPER WAVE IS EXPECTED TO MOVE ACROSS THE STATE THIS
EVENING...AND TRIGGER ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL KS. THIS ACTIVITY SHOULD MOVE ACROSS NORTHEAST KS THROUGH
THE EVENING. 18Z RUC SHOWS THE BETTER INSTABILITY CURRENTLY OVER
SOUTHERN KS WHERE THE DEWPOINTS ARE IN THE UPPER 50S. AS THE
SOUTHERLY WINDS CONTINUE TO BRING THE MOISTURE AND INSTABILITY INTO
EAST CENTRAL KS...THERE IS THE POTENTIAL THAT ANY CONVECTION IN
SOUTH CENTRAL KS COULD MOVE INTO THE AREA AND REMAIN ORGANIZED
ENOUGH FOR A SEVERE THREAT. PERHAPS THE GREATER THREAT FOR SEVERE
WEATHER MAY COME FROM ANY THUNDERSTORM DEVELOPMENT IN CENTRAL KS
THAT MOVES IN FROM THE WEST THIS EVENING. MODELS SHOW LOW LEVEL
SHEER INCREASING AS THE LOW LEVEL JET INCREASES. HOWEVER THE RAP
CONTINUES TO SHOW THE BEST INSTABILITY REMAINING ACROSS CENTRAL AND
SOUTHERN KS AND ALONG THE SOUTHWESTERN EDGE OF THE FORECAST AREA.
THERE COULD BE A SHORT WINDOW FOR SEVERE WEATHER IF DISCRETE STORMS
WERE ABLE TO FORM AND MOVE INTO THE AREA. GIVEN THE INCREASING 0-1KM
SHEER PARAMETERS...A TORNADO CAN NOT BE RULED OUT EITHER. EVENTUALLY
STORMS SHOULD BECOME MORE ELEVATED WITH CELL MERGERS DISRUPTING
UPDRAFT ORGANIZATION.
THINK THAT AS THE UPPER LEVEL WAVE PASSES EAST AROUND
MIDNIGHT...PRECIP CHANCES WILL QUICKLY DIMINISH OVERNIGHT. OVERNIGHT
LOWS SHOULD BE PRETTY MILD WITH CONTINUED SOUTH WINDS AND MOSTLY
CLOUDY SKIES PREVENTING MUCH IN THE WAY OF RADIATIONAL COOLING. SOME
OF THE OBJECTIVE GUIDANCE HAS LOW STRATUS MOVING IN WITH CONTINUED
MOISTURE ADVECTION FROM THE SOUTH. THEREFORE KEPT AT LEAST MOSTLY
CLOUDY SKIES IN THE FORECAST FOR TONIGHT.
FOR MONDAY FORECAST SOUNDINGS SHOW AN ELEVATED MIXED LAYER MOVING
OVER THE FORECAST AREA WITH LITTLE IN THE WAY OF LARGE SCALE FORCING
OR SURFACE BASED LIFT. BECAUSE OF THIS HAVE REMOVED POPS FOR MUCH OF
THE DAY THINKING THE BOUNDARY LAYER WILL REMAIN CAPPED. THE FORECAST
DOES SHOW CHANCES BEGINNING TO INCREASE LATE IN THE DAY AS DAY TIME
HEATING COULD CAUSE THE CAP TO WEAKEN ACROSS NORTH CENTRAL KS.
DEPENDING ON WHETHER THE LOW CLOUDS DEVELOP OR NOT...HIGHS SHOULD
MAKE IT INTO THE 70S. DID LOWER HIGHS A COUPLE DEGREES ACROSS EAST
CENTRAL KS WHERE CLOUDS ARE EXPECTED TO PERSIST LONGER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
BY THE EVENING HOURS ON MONDAY...A CONSIDERABLE EML MOVES OVER THE
MAJORITY OF THE CWA. HAVE BACKED OFF ON POPS AS A RESULT ALONG AND
SOUTH OF I70...AND MAY NEED TO BACK OFF EVEN MORE. TO THE
NORTH...THE CAP IS MUCH WEAKER...AND WOULD ANTICIPATE THAT BY
SUNRISE THERE WILL BE ENOUGH LIFT FROM THE LEADING WAVE AS WELL
AS CONVERGENCE IN THE LLJ AND THE SURFACE TROF FOR A LINE OF
THUNDERSTORMS ALONG THE KS NEBRASKA BORDER. COLD FRONT TO THE WEST
IS CONCURRENTLY SURGING TO THE SOUTHEAST AND MAY IMPINGE ON THE
FAR NW CORNER OF THE CWA BY AROUND 12Z TUESDAY...AND WILL CARRY
HIGHEST POPS TO THE NW.
CONDITIONS BY 12Z TUESDAY WILL BE IMPACTED BY PREVIOUS NIGHTS
WEATHER...BUT STILL APPEARS THAT LATE MORNING INTO THE EVENING
HOURS WILL BE THE GREATEST RISK FOR OUR FORECAST AREA FOR STRONG
TO SEVERE STORMS. THE DRYLINE AND FRONT COME TOGETHER OUT IN
WESTERN KANSAS IN THE MORNING AND BOTH MERGE AND MOVE INTO THE
WESTERN COUNTIES BY EARLY AFTERNOON. EC AND GFS SLIGHTLY SLOWER
AND COULD ALLOW FOR A BIT MORE BUILDUP OF INSTABILITY ACROSS THE
EAST BEFORE THE FRONT SURGES THROUGH LATE DAY. WITH WINDS THROUGH
THE COLUMN NEARLY RUNNING PARALLEL TO THE FRONT...DISCRETE CELLS
THAT INITIALLY FORM MAY EVOLVE QUICKLY INTO A LINE THAT ADVANCES
ACROSS THE CWA THROUGH THE EVENING HOURS. THIS WOULD MAKE SEVERE
WINDS THE PRIMARY CONCERN...ALTHOUGH WITH A QUICK INCREASE IN WIND
SPEEDS IN THE LOW LEVELS AND GOOD LOW LEVEL HELICITY CANT RULE OUT
ISOLATED TORNADOES...ESP IN EARLY ONSET OF THE CONVECTION AND IN
ANY STORMS THAT CAN FORM OUT IN THE WARM SECTOR.
TUESDAY NIGHT THROUGH FRIDAY BRING AN UNSEASONABLY COOL PERIOD AS
THE UPPER LOW CONTINUES TO DRAW COLDER AIR INTO THE PLAINS THROUGH
THE END OF THE WEEK. DAYTIME HIGHS WED WILL STRUGGLE TO REACH 40S
WHILE THURS AND FRI MAKE A SLOW CLIMB INTO THE MIDDLE 50S. BY THE
WEEKEND SOUTHERLY FLOW AT THE SURFACE AND WESTERLY FLOW ALOFT
BRING TEMPERATURES BACK TOWARD NORMAL WITH SOME CHANCES FOR RAIN
WITH SOME WEAK WAVES IN THE FLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1217 AM CDT MON APR 8 2013
FOR THE 06Z TAFS...THE REMNANTS OF THIS EVENING`S THUNDERSTORM
ACTIVITY WAS MOVING EAST OF THE AREA. THERE STILL MAY BE A FEW
VICINITY SHOWERS AND THUNDERSTORMS AROUND 06Z...BUT THESE SHOULD
QUICKLY MOVE EAST. MVFR CIGS/VIS EXPECTED THROUGH THE EARLY
OVERNIGHT HOURS...HOWEVER MODELS CONTINUE TO SHOW CIGS DROPPING DOWN
TO IFR CONDITIONS FOR A FEW HOURS THROUGH SUNRISE AND POSSIBLY
PERSIST INTO THE MID MORNING HOURS BEFORE LIFTING BACK TO MVFR
CONDITIONS. THE NAM IS SET ON KEEPING THE TAF SITES STUCK IN MVFR
CIGS THROUGH THE AFTERNOON WITH THE GFS SUGGESTING A FEW HOURS VFR
CONDITIONS POSSIBLE. THERE IS STILL UNCERTAINTY REGARDING THE
POTENTIAL FOR SOME SHOWERS AND THUNDERSTORMS TO DEVELOP LATER THIS
EVENING...BUT MODELS DO AGREE IN HAVING MVFR CIGS IN PLACE TOWARD
THE END OF THE TAF PERIOD.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GARGAN
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1219 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 959 PM CDT SUN APR 7 2013
UPDATED POPS/WX TO REFLECT THE LATEST RADAR TRENDS WITH THIS
EVENING`S THUNDERSTORM ACTIVITY. THUNDERSTORMS HAVE BEEN STEADILY
WEAKENING OVER THE LAST HOUR AND DIMINISHING IN COVERAGE ACROSS THE
FORECAST AREA. AS OF 03Z...THE LAST BAND OF THUNDERSTORMS WAS
TRACKING EAST ACROSS NORTHEASTERN KANSAS...HOWEVER A FEW ISOLATED
THUNDERSTORMS MAY STILL DEVELOP ACROSS EAST CENTRAL KANSAS THROUGH
LATE THIS EVENING. THESE LINGERING THUNDERSTORMS ARE ANTICIPATED TO
PROGRESS EAST OF THE CWA BY AROUND 06Z. AS A RESULT...HAVE TRENDED
WITH LOWERING POPS FROM WEST TO EAST ACROSS THE CWA THROUGH THE
REMAINDER OF THIS EVENING INTO THE EARLY OVERNIGHT HOURS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
19Z WATER VAPOR IMAGERY SHOWS A QUASI-ZONAL FLOW ACROSS THE PLAINS
WITH A LOW AMPLITUDE SHORTWAVE MOVING ACROSS THE CO AND NM ROCKIES.
AT THE SURFACE A TROUGH OF LOW PRESSURE IN THE LEE OF THE ROCKIES
HAS STRENGTHENED AND CAUSED SOUTH AND SOUTHEAST WINDS TO INCREASE
BRINGING BETTER MOISTURE NORTH INTO SOUTHERN AND EASTERN KS.
THE UPPER WAVE IS EXPECTED TO MOVE ACROSS THE STATE THIS
EVENING...AND TRIGGER ADDITIONAL THUNDERSTORM DEVELOPMENT ACROSS
CENTRAL KS. THIS ACTIVITY SHOULD MOVE ACROSS NORTHEAST KS THROUGH
THE EVENING. 18Z RUC SHOWS THE BETTER INSTABILITY CURRENTLY OVER
SOUTHERN KS WHERE THE DEWPOINTS ARE IN THE UPPER 50S. AS THE
SOUTHERLY WINDS CONTINUE TO BRING THE MOISTURE AND INSTABILITY INTO
EAST CENTRAL KS...THERE IS THE POTENTIAL THAT ANY CONVECTION IN
SOUTH CENTRAL KS COULD MOVE INTO THE AREA AND REMAIN ORGANIZED
ENOUGH FOR A SEVERE THREAT. PERHAPS THE GREATER THREAT FOR SEVERE
WEATHER MAY COME FROM ANY THUNDERSTORM DEVELOPMENT IN CENTRAL KS
THAT MOVES IN FROM THE WEST THIS EVENING. MODELS SHOW LOW LEVEL
SHEER INCREASING AS THE LOW LEVEL JET INCREASES. HOWEVER THE RAP
CONTINUES TO SHOW THE BEST INSTABILITY REMAINING ACROSS CENTRAL AND
SOUTHERN KS AND ALONG THE SOUTHWESTERN EDGE OF THE FORECAST AREA.
THERE COULD BE A SHORT WINDOW FOR SEVERE WEATHER IF DISCRETE STORMS
WERE ABLE TO FORM AND MOVE INTO THE AREA. GIVEN THE INCREASING 0-1KM
SHEER PARAMETERS...A TORNADO CAN NOT BE RULED OUT EITHER. EVENTUALLY
STORMS SHOULD BECOME MORE ELEVATED WITH CELL MERGERS DISRUPTING
UPDRAFT ORGANIZATION.
THINK THAT AS THE UPPER LEVEL WAVE PASSES EAST AROUND
MIDNIGHT...PRECIP CHANCES WILL QUICKLY DIMINISH OVERNIGHT. OVERNIGHT
LOWS SHOULD BE PRETTY MILD WITH CONTINUED SOUTH WINDS AND MOSTLY
CLOUDY SKIES PREVENTING MUCH IN THE WAY OF RADIATIONAL COOLING. SOME
OF THE OBJECTIVE GUIDANCE HAS LOW STRATUS MOVING IN WITH CONTINUED
MOISTURE ADVECTION FROM THE SOUTH. THEREFORE KEPT AT LEAST MOSTLY
CLOUDY SKIES IN THE FORECAST FOR TONIGHT.
FOR MONDAY FORECAST SOUNDINGS SHOW AN ELEVATED MIXED LAYER MOVING
OVER THE FORECAST AREA WITH LITTLE IN THE WAY OF LARGE SCALE FORCING
OR SURFACE BASED LIFT. BECAUSE OF THIS HAVE REMOVED POPS FOR MUCH OF
THE DAY THINKING THE BOUNDARY LAYER WILL REMAIN CAPPED. THE FORECAST
DOES SHOW CHANCES BEGINNING TO INCREASE LATE IN THE DAY AS DAY TIME
HEATING COULD CAUSE THE CAP TO WEAKEN ACROSS NORTH CENTRAL KS.
DEPENDING ON WHETHER THE LOW CLOUDS DEVELOP OR NOT...HIGHS SHOULD
MAKE IT INTO THE 70S. DID LOWER HIGHS A COUPLE DEGREES ACROSS EAST
CENTRAL KS WHERE CLOUDS ARE EXPECTED TO PERSIST LONGER.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 255 PM CDT SUN APR 7 2013
BY THE EVENING HOURS ON MONDAY...A CONSIDERABLE EML MOVES OVER THE
MAJORITY OF THE CWA. HAVE BACKED OFF ON POPS AS A RESULT ALONG AND
SOUTH OF I70...AND MAY NEED TO BACK OFF EVEN MORE. TO THE
NORTH...THE CAP IS MUCH WEAKER...AND WOULD ANTICIPATE THAT BY
SUNRISE THERE WILL BE ENOUGH LIFT FROM THE LEADING WAVE AS WELL
AS CONVERGENCE IN THE LLJ AND THE SURFACE TROF FOR A LINE OF
THUNDERSTORMS ALONG THE KS NEBRASKA BORDER. COLD FRONT TO THE WEST
IS CONCURRENTLY SURGING TO THE SOUTHEAST AND MAY IMPINGE ON THE
FAR NW CORNER OF THE CWA BY AROUND 12Z TUESDAY...AND WILL CARRY
HIGHEST POPS TO THE NW.
CONDITIONS BY 12Z TUESDAY WILL BE IMPACTED BY PREVIOUS NIGHTS
WEATHER...BUT STILL APPEARS THAT LATE MORNING INTO THE EVENING
HOURS WILL BE THE GREATEST RISK FOR OUR FORECAST AREA FOR STRONG
TO SEVERE STORMS. THE DRYLINE AND FRONT COME TOGETHER OUT IN
WESTERN KANSAS IN THE MORNING AND BOTH MERGE AND MOVE INTO THE
WESTERN COUNTIES BY EARLY AFTERNOON. EC AND GFS SLIGHTLY SLOWER
AND COULD ALLOW FOR A BIT MORE BUILDUP OF INSTABILITY ACROSS THE
EAST BEFORE THE FRONT SURGES THROUGH LATE DAY. WITH WINDS THROUGH
THE COLUMN NEARLY RUNNING PARALLEL TO THE FRONT...DISCRETE CELLS
THAT INITIALLY FORM MAY EVOLVE QUICKLY INTO A LINE THAT ADVANCES
ACROSS THE CWA THROUGH THE EVENING HOURS. THIS WOULD MAKE SEVERE
WINDS THE PRIMARY CONCERN...ALTHOUGH WITH A QUICK INCREASE IN WIND
SPEEDS IN THE LOW LEVELS AND GOOD LOW LEVEL HELICITY CANT RULE OUT
ISOLATED TORNADOES...ESP IN EARLY ONSET OF THE CONVECTION AND IN
ANY STORMS THAT CAN FORM OUT IN THE WARM SECTOR.
TUESDAY NIGHT THROUGH FRIDAY BRING AN UNSEASONABLY COOL PERIOD AS
THE UPPER LOW CONTINUES TO DRAW COLDER AIR INTO THE PLAINS THROUGH
THE END OF THE WEEK. DAYTIME HIGHS WED WILL STRUGGLE TO REACH 40S
WHILE THURS AND FRI MAKE A SLOW CLIMB INTO THE MIDDLE 50S. BY THE
WEEKEND SOUTHERLY FLOW AT THE SURFACE AND WESTERLY FLOW ALOFT
BRING TEMPERATURES BACK TOWARD NORMAL WITH SOME CHANCES FOR RAIN
WITH SOME WEAK WAVES IN THE FLOW.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1217 AM CDT MON APR 8 2013
FOR THE 06Z TAFS...THE REMNANTS OF THIS EVENING`S THUNDERSTORM
ACTIVITY WAS MOVING EAST OF THE AREA. THERE STILL MAY BE A FEW
VICINITY SHOWERS AND THUNDERSTORMS AROUND 06Z...BUT THESE SHOULD
QUICKLY MOVE EAST. MVFR CIGS/VIS EXPECTED THROUGH THE EARLY
OVERNIGHT HOURS...HOWEVER MODELS CONTINUE TO SHOW CIGS DROPPING DOWN
TO IFR CONDITIONS FOR A FEW HOURS THROUGH SUNRISE AND POSSIBLY
PERSIST INTO THE MID MORNING HOURS BEFORE LIFTING BACK TO MVFR
CONDITIONS. THE NAM IS SET ON KEEPING THE TAF SITES STUCK IN MVFR
CIGS THROUGH THE AFTERNOON WITH THE GFS SUGGESTING A FEW HOURS VFR
CONDITIONS POSSIBLE. THERE IS STILL UNCERTAINTY REGARDING THE
POTENTIAL FOR SOME SHOWERS AND THUNDERSTORMS TO DEVELOP LATER THIS
EVENING...BUT MODELS DO AGREE IN HAVING MVFR CIGS IN PLACE TOWARD
THE END OF THE TAF PERIOD.
ACH
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HENNECKE
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1112 PM MDT SUN APR 7 2013
.UPDATE...
ISSUED AT 956 PM MDT SUN APR 7 2013
INCREASED DEW POINTS TONIGHT...ESPECIALLY IN THE EASTERN THIRD OF
THE FORECAST AREA...GIVEN LATEST MODEL GUIDANCE AND SURFACE
ANALYSIS. ADDED SOME PATCHY FOG EAST OF HIGHWAY 83 WHERE DEW POINT
DEPRESSIONS WILL BE NEAR ZERO.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 233 PM MDT SUN APR 7 2013
LATER THIS AFTERNOON MODELS CONTINUE TO INDICATE MUCAPE AROUND
500J/KG OR SO JUST EAST OF A SURFACE TROUGH EAST OF A GOVE TO HILL
CITY LINE. 0-6KM SHEAR OF 40 KTS WILL BE FAVORABLE FOR STRONG/SEVERE
STORMS TO DEVELOP...HOWEVER THERE WILL BE SOME SUBSIDENCE
INTERSPERCED WITH LIFT BEHIND THE EXITING SHORT WAVE TROUGH. IF
SEVERE THUNDERSTORMS DO DEVELOP...AM ANTICIPATING THEM TO BE ONLY
ISOLATED WITH HAIL UP TO QUARTER SIZE AND GUSTY OUTFLOW WINDS. THE
STRONG/SEVERE ACTIVITY SHOULD QUICKLY DIMINISH DURING THE EARLY
EVENING AS THE ENVIRONMENT BECOMES MORE STABLE.
TONIGHT SOME LINGERING LIFT BEHIND THE UPPER LEVEL SHORT WAVE TROUGH
WILL MOVE INTO THE AREA THIS EVENING FROM THE WEST...WITH SOME LIFT
OVER THE FAR EASTERN PART OF THE AREA AS WELL. THE LIFT WILL MOVE
THROUGH THE AREA AND WEAKEN DURING THE LATE EVENING. DUE TO THE DRY
ENVIRONMENT BELOW 700MB OR SO...AND SUBTLE NATURE OF THE LIFT WILL
ONLY HAVE SLIGHT CHANCES FOR PRECIP. OVERNIGHT SUBSIDENCE AND DRIER
AIR MOVE INTO THE AREA BRINGING ANY PRECIP. TO AN END.
MONDAY AM ANTICIPATING ELEVATED THUNDERSTORMS TO BEGIN OVER EAST
CENTRAL COLORADO DURING THE EARLY AFTERNOON AS LIFT FROM A SHORT
WAVE TROUGH OVERSPREADS THE AREA. SOUNDINGS DURING THE EARLY
AFTERNOON REMAIN FAIRLY DRY UNTIL MOISTURE ADVECTION INCREASES WITH
STRENGTHENING LOW LEVEL JET DURING THE MID AND LATE AFTERNOON...SO
HAVE SLOWED HOW QUICKLY PRECIP. CHANCES INCREASE DURING THE
AFTERNOON. A WARM FRONT WILL MOVE INTO THE AREA DURING THE LATE
MORNING AND AFTERNOON. MODELS GENERALLY PLACE THE WARM FRONT BETWEEN
HWY 24 AND THE NEBRASKA BORDER. THE POSITION OF THE DRY LINE IS A
BIT HARDER TO PLACE...WITH MODELS EITHER KEEPING IT ALONG THE KS/CO
BORDER OR FURTHER EAST INTO WEST CENTRAL/SOUTHWEST KANSAS. THE
SREF/ECMWF/GFS GENERALLY PLACE IT ALONG THE KS/CO BORDER...SO WILL
SIDE WITH THEM. THIS PLACES THE INTERSECTION OF THE DRY LINE/WARM
FRONT NEAR THE CENTRAL PART OF THE TRI-STATE AREA. AM THINKING THE
STRONGER STORMS SHOULD BEGIN TO INITIATE TOWARD EARLY/MID AFTERNOON
NEAR THE INTERSECTION AS THE MOISTURE ADVECTION INCREASES
INSTABILITY. NAM POINT SOUNDINGS SHOW SLIGHTLY MORE INSTABILITY
ALONG THE DRY LINE THAN THE WARM FRONT. IN ADDITION MORE LIFT WILL
BE ALONG THE DRY LINE THAN THE WARM FRONT...SO AM THINKING STORMS SHOULD
FIRE ALONG THE DRY LINE FIRST THEN THE WARM FRONT. AS THE AFTERNOON
PROGRESSES THE WARM FRONT WILL ARK TO THE NORTHWEST...CAUSING THE
ENVIRONMENT TO BECOME MORE UNSTABLE OVER THE NORTHERN PART OF THE
AREA. THUNDERSTORM COVERAGE WILL INCREASE DURING THE MID TO LATE
AFTERNOON AS CAPE AND SYNOPTIC LIFT INCREASE OVER THE AREA.
DURING THE LATE AFTERNOON THE ENVIRONMENT SOUTH AND EAST OF HWY 40
BECOMES INCREASINGLY FAVORABLE FOR TON ADO DEVELOPMENT WITH 0-1KM
BULK SHEAR AROUND 15KTS AND EHI OF 3.5M2/S2. THE LARGE HAIL THREAT
LOOKS VERY GOOD...ESPECIALLY DURING THE MID TO LATE AFTERNOON AS THE
CAPE PROFILE IN THE HAIL GROWTH ZONE INCREASES AND MUCAPE NEARS
2000-3000J/KG.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 233 PM MDT SUN APR 7 2013
UPPER FLOW WILL BE SOUTHWEST MONDAY NIGHT AHEAD OF AN UPPER LOW THAT
WILL MOVE INTO COLORADO TUESDAY. THE UPPER LOW WILL MOVE INTO
SOUTHWEST NEBRASKA TUESDAY NIGHT AND GRADUALLY SHIFT EAST INTO SOUTH
CENTRAL NEBRASKA WEDNESDAY. SURFACE LOW PRESSURE WILL MOVE INTO
SOUTHEAST COLORADO MONDAY NIGHT AND THEN MOVE EAST INTO SOUTH
CENTRAL KANSAS TUESDAY. A COLD FRONT WILL MOVE INTO EASTERN COLORADO
TUESDAY. THIS FRONT WILL PUSH ACROSS THE ENTIRE FA BY 18Z TUESDAY.
SURFACE WINDS SHOULD RANGE FROM 25 TO 35 KTS. HIGH PRESSURE WILL
CONTINUE TO BUILD INTO THE CENTRAL PLAINS WEDNESDAY. WIND WILL NOT
BE AS STRONG ON WEDNESDAY.
FOR MONDAY NIGHT...FOR EARLY EVENING...A SHORTWAVE COMES THROUGH
WITH MOISTURE AND GOOD LIFT EAST OF THE COLORADO LINE. CAPE VALUES
WILL RANGE FROM 700 J/KG IN EASTERN COLORADO TO 2500 NEAR HILL CITY.
BEST CAPE VALUES ARE GENERALLY EAST OF THE COLORADO STATE LINE AS
WELL. BY 03Z TUESDAY CONVECTIVE INHIBITION SHOULD TAKE OVER. AROUND
MIDNIGHT GOOD MOISTURE AND LIFT WILL MOVE INTO AN AREA GENERALLY
NORTH OF INTERSTATE 70. A COLD FRONT WILL ALSO MOVE INTO THE
NORTHWEST FA BRINGING COLDER AIR INTO THE REGION. PRECIPITATION WILL
CHANGE TO SNOW OVER THE FAR NORTHWEST FA. POPS WILL RANGE FROM
CHANCE IN THE SOUTH TO CATEGORICAL IN THE NORTHWEST.
TUESDAY...THE COLD FRONT WILL MOVE THROUGH THE REST OF THE FA BY 18Z
WITH SUSTAINED WIND AROUND 25KTS. THIS MAY REQUIRE A WIND ADVISORY.
GOOD MOISTURE AND LIFT WILL MOVE INTO THE NORTHWEST HALF OF THE FA
WITH THE FRONT. BY AFTERNOON, A DRY SLOT WILL MOVE INTO THE
SOUTHEAST FA. PRECIPITATION WILL CHANGE TO SNOW BEHIND THE FRONT
CAUSING SNOW TO SPREAD INTO NORTHWEST KANSAS AND SOUTHWEST NEBRASKA
TUESDAY MORNING. SNOW WILL CONTINUE TO SPREAD EAST ACROSS NORTHWEST
KANSAS DURING THE AFTERNOON. POPS WILL RANGE FROM CHANCE IN THE
SOUTH TO CATEGORICAL IN THE NORTH. PLAN TO CONTINUE THE WINTER
STORM WATCH FOR YUMA COUNTY WHERE TOTAL SNOWFALL WILL RANGE FROM 5
TO 6 INCHES IN THE NORTHWEST CORNER OF THE COUNTY. OTHERWISE
SNOWFALL AMOUNTS SHOULD RANGE FROM 1 TO 2 INCHES MAINLY ACROSS THE
NORTHWEST HALF OF THE FA WITH AMOUNTS LESS THAN AN INCH ACROSS THE
EAST.
TUESDAY NIGHT...THE DRY SLOT CONTINUES TO AFFECT THE SOUTHEAST ZONES
IN THE EVENING. THE BEST MOISTURE AND LIFT WILL BE CONFINED TO THE
FAR NORTHERN ZONES. LIFT CONTINUES TO MOVE NORTHWARD WITH THE LOW
THROUGH THE NIGHT. SUBSIDENCE IS OVER THE SOUTHERN FA AFTER
MIDNIGHT. POPS WILL DECREASE FROM LIKELY IN THE NORTH TO CHANCE WITH
CHANCE TO SLIGHT CHANCE POPS ELSEWHERE.
WEDNESDAY...DYNAMICS ARE WELL NORTH OF THE FA SO POPS WILL BE SLIGHT
CHANCE AND CHANCE MAINLY OVER THE NORTHEAST PORTION OF THE FA.
PRECIPITATION SHOULD END OTHER THAN SOME LIGHT PRECIPITATION IN THE
FAR NORTHEAST IN THE AFTERNOON.
MIN TEMPERATURES MONDAY NIGHT WILL VARY WIDELY FROM THE LOWER 20S IN
EASTERN COLORADO TO THE UPPER 40S IN THE EAST. MIN TEMPERATURES
TUESDAY NIGHT WILL BE IN THE MID TEENS TO THE LOWER 20S. MAX
TEMPERATURES TUESDAY WILL RANGE FROM THE MID 20S IN EASTERN COLORADO
TO NEAR 50 IN THE EAST. MAX TEMPERATURES WEDNESDAY WILL RISE INTO
THE MID/UPPER 30S.
IN THE EXTENDED...(WEDNESDAY NIGHT THROUGH SUNDAY)...UPPER FLOW
WILL BE NORTHWEST THROUGH THIS PERIOD. OTHER THAN A SLIGHT CHANCE
OF LIGHT RAIN AND SNOW SHOWERS THURSDAY NIGHT THE FORECAST SHOULD
BE DRY. ANOTHER WEAK WAVE COMES THROUGH THE FLOW SATURDAY NIGHT
BUT DYNAMICS ARE VERY WEAK. THERE WILL BE A SLIGHT CHANCE OF LIGHT
RAIN SHOWERS ACROSS THE FAR NORTH.
TEMPERATURES WEDNESDAY NIGHT WILL BE THE COLDEST WITH SNOW ON THE
GROUND. EXPECT LOW TEMPERATURES IN THE UPPER TEENS TO AROUND 20. LOW
TEMPERATURES WILL MODERATE TO THE LOWER 30S THURSDAY NIGHT AND INTO
THE UPPER 30S/LOWER 40S SUNDAY NIGHT. HIGH TEMPERATURES THURSDAY
WILL STRUGGLE TO RISE OUT OF THE 30S WITH SNOW ON THE GROUND. MAX
TEMPERATURES WILL MODERATE TO THE LOWER 50S FRIDAY AND INTO THE
UPPER 60S SATURDAY/SUNDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1112 PM MDT SUN APR 7 2013
STRATUS IS BEGINNING TO FORM AT KHLC AS SURFACE DEW POINTS SLOWLY
INCREASE AND DEW POINT DEPRESSIONS DECREASE. EVEN WITH MID LEVEL
CLOUDS MOVING OVER KMCK...DECIDED TO ADD SOME MVFR CIGS/VISIBILITIES
THERE AFTER 10Z. LATEST HRRR MODEL SUPPORTS THIS THINKING.
MOISTURE WILL BE SLOWER TO RETURN AT KGLD...AND WILL CONTINUE VFR
CONDITIONS THERE THROUGH THE NIGHT. CONVECTION WILL LIKELY DEVELOP
AFTER 21Z ACROSS NORTHWEST KANSAS AND SOUTHWEST NEBRASKA. WILL
MENTION TSRA AT BOTH SITES DURING THE LATE AFTERNOON/EVENING. THERE
IS STILL A QUESTION ABOUT THE EXACT LOCATION OF CONVECTIVE INITIATION...
BUT IF THE STORMS FORM...THEY WILL LIKELY BECOME SEVERE RAPIDLY.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...WINTER STORM WATCH FROM LATE MONDAY NIGHT THROUGH TUESDAY
AFTERNOON FOR COZ090.
NE...NONE.
&&
$$
UPDATE...MENTZER
SHORT TERM...JTL
LONG TERM...FS
AVIATION...MENTZER
AREA FORECAST DISCUSSION
NWS GRAY ME
704 PM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES REGION TONIGHT
THEN MOVE QUICKLY ACROSS NORTHERN NEW ENGLAND AND THROUGH THE GULF
OF MAINE ON TUESDAY. THIS WILL GIVE US A PERIOD OF RAIN LATE
TONIGHT INTO TUESDAY WITH SNOW POSSIBLE OVER MORE NORTHERN AREAS.
THE LOW WILL MOVE QUICKLY OUT TO SEA TUESDAY EVENING AS FAIR
WEATHER SETTLES IN BRIEFLY. A FRONTAL SYSTEM SETS UP OVER THE
REGION AS LOW PRESSURE HEADS EAST ALONG IT TUESDAY NIGHT BRINGING
A CHANCE OF MORE RAIN LATE TUESDAY NIGHT. THE WEST TO EAST FRONT
DRAPED ACROSS THE REGION THEN PROVIDES CLOUDS AND UNSETTLED
WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST ALONG
THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF PRECIPITATION
ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING CLOUDS AND A FEW
MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY SATURDAY. HIGH PRESSURE
WILL BUILD EAST FROM THE GREAT LAKES FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /THROUGH TUESDAY/...
UPDATE...
SEA BREEZES KNOCKED TEMPS DOWN ALONG THE COAST DURING THE LAST 2
HOURS. NEVERTHELESS...NW BREEZES ALLOWED PORTLAND TO TOP OUT AT THEIR HIGHEST
TEMPERATURE OF THE YEAR...REACHING 61 DEGREES. TO ACCOMPLISH THIS
FEET...WE HAD TO MOVE HIGHER THAN THE 59 DEGREES...SET BACK ON
JANUARY 14TH!
LATEST RUC SHOWS PCPN REACHING WRN PTNS OF OUR FORECAST AREA
SHORTLY AFTER MIDNIGHT. IN THE MEANTIME...CLOUDS WILL OVERSPREAD
THE REGION THIS EVENING FROM WEST TO EAST.
MADE MINOR ADJUSTMENTS TO THE DEW POINT AND WIND FIELDS.
OTRW...LITTLE IN THE WAY OF CHANGES TO THE GRIDS.
PREV DISC...
SFC HIGH MOVES QUICKLY OUT TO SEA THIS EVE AS LOW PRES
MOVES E FROM THE GREAT LAKES REGION TNGT. THE LOW IS ASSOCIATED
WITH AN UPR LVL TROF THAT IS MOVING QUICKLY E THRU THE STRONG
WESTERLIES ALOFT. THE LOW WILL SPREAD CLOUDS THEN RA E INTO THE
FCST AREA OVERNIGHT. TEMP PROFILE MAY BE COLD ENOUGH FOR -SN OR
-RASN OVER OUR MORE NRN ZONES IN ME...IN PARTICULAR NRN FRANKLIN
AND CENTRAL SOMERSET COUNTIES AS WELL AS THE HIGHEST TERRAIN IN
THE WHITE MTS OF NRN NH. HOWEVER...ANY ACCUMULATION WILL BE LGT IF
ANY AT ALL.
TEMPS WILL STAY MILD RANGING FROM THE MID 30S N TO THE LOWER 40S S
EXCEPT FOR SOME LOWER 30S ACROSS FAR NRN ZONES WHERE THE -SN IS
PSBL. LGT WINDS WILL TURN TO AN EASTERLY DIRECTION AHEAD OF THE
APPROACHING LOW.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE NEAR TERM
FCST.
&&
.SHORT TERM /TUESDAY NIGHT/...
THE UPR LVL SHORT WAVE TROF MOVES QUICKLY TO THE E AS THE UPR LVL
FLOW CONTINUES VERY STRONG ON TUESDAY. THIS BRINGS THE SFC LOW
ACROSS NRN NEW ENGLAND TUESDAY MORNING AND THRU THE GULF OF MAINE
TUESDAY AFTERNOON. THIS WILL CONT RA...OR SN/MIXED RASN FAR NRN
ZONES INTO TUESDAY WITH DRIER WX AND SOME CLEARING TO FOLLOW
TUESDAY AFTERNOON OVER NH AND FROM MID TO LATE AFTERNOON OVER ME.
FAIR WX TUESDAY EVE IN THE WAKE OF THE LOW. HOWEVER...A FNT SETS
UP OVER THE REGION WITH WEAK LOW PRES APPROACHING FROM THE W. THIS
WILL BRING MORE CLOUDS BACK IN WITH A CHC OF RA LATE TUESDAY NGT.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE SHORT TERM
FCST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WE BEGIN THE PERIOD WITH A FLAT RIDGE TO OUR SOUTH AND AN UPPER
VORTEX OVER EASTERN CANADA WITH FORECAST AREA JUST TO THE SOUTH OF
THE MEAN JET AXIS. UPSTREAM...AN UPPER TROUGH WILL BE SITUATED
JUST TO THE LEE OF THE ROCKIES. THAT UPPER TROUGH LIFTS OUT INTO
THE GREAT LAKES BY LATE IN THE WORKWEEK WHEN FORECAST CONFIDENCE
DIMINISHES IN INCREASING MODEL SPREAD. IN THE DAILIES...A WEST TO
EAST FRONT DRAPED ACROSS THE REGION WILL PROVIDE CLOUDS AND
UNSETTLED WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST
ALONG THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF
PRECIPITATION ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING
CLOUDS AND A FEW MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY
SATURDAY. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT LAKES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY NIGHT/...MVFR CIG AT HIE AT 17Z TDA
WILL QUICKLY BECOME VFR AS CLOUDS DISSIPATE PER SATELLITE LOOP.
OTRW VFR THRU THIS EVE...THEN LOWERING TO MVFR/PSBL IFR IN
DEVELOPING RA LATER TNGT AND CONTINUING THRU TUESDAY MORNING OVER
NH AND INTO TUESDAY AFTERNOON OVER ME AS LOW PRES MOVES E FROM
THE GREAT LAKES AND THRU NRN NEW ENGLAND. IMPROVING WX TUESDAY
AFTERNOON AS THE LOW MOVES QUICKLY THRU THE GULF OF MAINE.
LONG TERM...
WED - THU...AREAS OF MVFR POSSIBLE IN RAIN SHOWERS.
FRI...MVFR LIKELY IN RAIN WITH LCL IFR POSSIBLE IN FOG.
SFC WND GUSTS TO 25 KT POSSIBLE VCNTY OF COAST.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...HIGH PRES MOVES E
THIS EVE FOLLOWED BY APPROACHING LOW PRES FROM THE GREAT LAKES
TNGT. THE LOW MOVES THRU NRN NEW ENGLAND TUESDAY MORNING THEN
QUICKLY THRU THE GULF OF MAINE TUESDAY AFTERNOON. PRES PATTERN
WEAK THIS EVE BUT INCREASES WITH THE PASSING LOW...BUT NOT ENOUGH
TO GENERATE SCA LEVEL WINDS. SEAS INCREASE WITH THE SYSTEM MOVING
THRU BUT NOT TO SCA LEVELS FOR MOST OF THE WATERS. THE OUTER MOST
WATERS MAY REACH THE 5 FT SCA CRITERIA FOR A BRIEF PERIOD AS THE
LOW MOVES BY.
LONG TERM...
THU NIGHT - FRI...SMALL CRAFT CONDITIONS ARE LIKELY.
&&
.FIRE WEATHER...
RAIN MOVING IN LATER TNGT THEN ENDING W TO E TUESDAY WILL PROVIDE
QPF OF 1/4 TO 1/2 INCH ACROSS MUCH OF THE REGION. DRY WX FOLLOWS
BRIEFLY TUESDAY EVE THEN MORE SHRA ACTIVITY MOVES IN FOR THE REST
OF THE WORK WEEK AS A FRONTAL SYSTEM FORMS AND REMAINS STAGNANT
OVER OR JUST S OF THE REGION...WITH THE BEST CHC FOR WIDESPREAD
SIGNIFICANT PRCP THURSDAY NGT THRU FRIDAY NGT. PRCP MOSTLY RA...
BUT SN OR MIXED RASN PSBL N/MT AREAS AND MAYBE EVEN FURTHER S LATE
IN THE WEEK. THE WET WX AND HIGH RH VALUES ALONG WITH FAIRLY WEAK
WINDS THRU FRIDAY SHOULD PROVIDE FOR VERY LOW FIRE DANGER.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
443 PM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL MOVE EAST FROM THE GREAT LAKES REGION TONIGHT
THEN MOVE QUICKLY ACROSS NORTHERN NEW ENGLAND AND THROUGH THE GULF
OF MAINE ON TUESDAY. THIS WILL GIVE US A PERIOD OF RAIN LATE
TONIGHT INTO TUESDAY WITH SNOW POSSIBLE OVER MORE NORTHERN AREAS.
THE LOW WILL MOVE QUICKLY OUT TO SEA TUESDAY EVENING AS FAIR
WEATHER SETTLES IN BRIEFLY. A FRONTAL SYSTEM SETS UP OVER THE
REGION AS LOW PRESSURE HEADS EAST ALONG IT TUESDAY NIGHT BRINGING
A CHANCE OF MORE RAIN LATE TUESDAY NIGHT. THE WEST TO EAST FRONT
DRAPED ACROSS THE REGION THEN PROVIDES CLOUDS AND UNSETTLED
WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST ALONG
THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF PRECIPITATION
ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING CLOUDS AND A FEW
MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY SATURDAY. HIGH PRESSURE
WILL BUILD EAST FROM THE GREAT LAKES FOR SUNDAY AND MONDAY.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
UPDATE...
THE SEA BREEZE SHOULD KICK IN ALONG THE IMMDIATE COASTLINE DURING
THE NEXT HOUR. HOWEVER...NW BREEZES ALLOWED PORTLAND TO TOP OUT AT
THEIR HIGHEST TEMPERATURE OF THE YEAR...REACHING 61 DEGREES.
LATEST RUC SHOWS PCPN REACHING WRN PTNS OF OUR FORECAST AREA
SHORTLY AFTER MIDNIGHT. IN THE MEANTIME...CLOUDS WILL OVERSPREAD
THE REGION THIS EVENING FROM WEST TO EAST.
MADE MINOR ADJUSTMENTS TO THE DEW POINT AND WIND FIELDS.
OTRW...LITTLE IN THE WAY OF CHANGES TO THE GRIDS.
PREV DISC...
SFC HIGH MOVES QUICKLY OUT TO SEA THIS EVE AS LOW PRES
MOVES E FROM THE GREAT LAKES REGION TNGT. THE LOW IS ASSOCIATED
WITH AN UPR LVL TROF THAT IS MOVING QUICKLY E THRU THE STRONG
WESTERLIES ALOFT. THE LOW WILL SPREAD CLOUDS THEN RA E INTO THE
FCST AREA OVERNIGHT. TEMP PROFILE MAY BE COLD ENOUGH FOR -SN OR
-RASN OVER OUR MORE NRN ZONES IN ME...IN PARTICULAR NRN FRANKLIN
AND CENTRAL SOMERSET COUNTIES AS WELL AS THE HIGHEST TERRAIN IN
THE WHITE MTS OF NRN NH. HOWEVER...ANY ACCUMULATION WILL BE LGT IF
ANY AT ALL.
TEMPS WILL STAY MILD RANGING FROM THE MID 30S N TO THE LOWER 40S S
EXCEPT FOR SOME LOWER 30S ACROSS FAR NRN ZONES WHERE THE -SN IS
PSBL. LGT WINDS WILL TURN TO AN EASTERLY DIRECTION AHEAD OF THE
APPROACHING LOW.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE NEAR TERM
FCST.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
THE UPR LVL SHORT WAVE TROF MOVES QUICKLY TO THE E AS THE UPR LVL
FLOW CONTINUES VERY STRONG ON TUESDAY. THIS BRINGS THE SFC LOW
ACROSS NRN NEW ENGLAND TUESDAY MORNING AND THRU THE GULF OF MAINE
TUESDAY AFTERNOON. THIS WILL CONT RA...OR SN/MIXED RASN FAR NRN
ZONES INTO TUESDAY WITH DRIER WX AND SOME CLEARING TO FOLLOW
TUESDAY AFTERNOON OVER NH AND FROM MID TO LATE AFTERNOON OVER ME.
FAIR WX TUESDAY EVE IN THE WAKE OF THE LOW. HOWEVER...A FNT SETS
UP OVER THE REGION WITH WEAK LOW PRES APPROACHING FROM THE W. THIS
WILL BRING MORE CLOUDS BACK IN WITH A CHC OF RA LATE TUESDAY NGT.
GENERALLY USED A BLEND OF NAM, GFS, CMC AND 00Z ECMWF MODELS,
BLEND OF MAV/MET MOS AND A BLEND OF RFC/HPC QPF FOR THE SHORT TERM
FCST.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
WE BEGIN THE PERIOD WITH A FLAT RIDGE TO OUR SOUTH AND AN UPPER
VORTEX OVER EASTERN CANADA WITH FORECAST AREA JUST TO THE SOUTH OF
THE MEAN JET AXIS. UPSTREAM...AN UPPER TROUGH WILL BE SITUATED
JUST TO THE LEE OF THE ROCKIES. THAT UPPER TROUGH LIFTS OUT INTO
THE GREAT LAKES BY LATE IN THE WORKWEEK WHEN FORECAST CONFIDENCE
DIMINISHES IN INCREASING MODEL SPREAD. IN THE DAILIES...A WEST TO
EAST FRONT DRAPED ACROSS THE REGION WILL PROVIDE CLOUDS AND
UNSETTLED WEATHER WEDNESDAY AND THURSDAY. LOW PRESSURE MOVING EAST
ALONG THIS FRONT WILL PROVIDE A STEADIER AND HEAVIER ROUND OF
PRECIPITATION ON FRIDAY. IN THE WAKE OF THIS SYSTEM...LINGERING
CLOUDS AND A FEW MOUNTAIN RAIN OR SNOW SHOWERS ARE LIKELY
SATURDAY. HIGH PRESSURE WILL BUILD EAST FROM THE GREAT LAKES FOR
SUNDAY AND MONDAY.
&&
.AVIATION /21Z MONDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH TUESDAY NIGHT/...MVFR CIG AT HIE AT 17Z TDA
WILL QUICKLY BECOME VFR AS CLOUDS DISSIPATE PER SATELLITE LOOP.
OTRW VFR THRU THIS EVE...THEN LOWERING TO MVFR/PSBL IFR IN
DEVELOPING RA LATER TNGT AND CONTINUING THRU TUESDAY MORNING OVER
NH AND INTO TUESDAY AFTERNOON OVER ME AS LOW PRES MOVES E FROM
THE GREAT LAKES AND THRU NRN NEW ENGLAND. IMPROVING WX TUESDAY
AFTERNOON AS THE LOW MOVES QUICKLY THRU THE GULF OF MAINE.
LONG TERM...
WED - THU...AREAS OF MVFR POSSIBLE IN RAIN SHOWERS.
FRI...MVFR LIKELY IN RAIN WITH LCL IFR POSSIBLE IN FOG.
SFC WND GUSTS TO 25 KT POSSIBLE VCNTY OF COAST.
&&
.MARINE...
SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...HIGH PRES MOVES E
THIS EVE FOLLOWED BY APPROACHING LOW PRES FROM THE GREAT LAKES
TNGT. THE LOW MOVES THRU NRN NEW ENGLAND TUESDAY MORNING THEN
QUICKLY THRU THE GULF OF MAINE TUESDAY AFTERNOON. PRES PATTERN
WEAK THIS EVE BUT INCREASES WITH THE PASSING LOW...BUT NOT ENOUGH
TO GENERATE SCA LEVEL WINDS. SEAS INCREASE WITH THE SYSTEM MOVING
THRU BUT NOT TO SCA LEVELS FOR MOST OF THE WATERS. THE OUTER MOST
WATERS MAY REACH THE 5 FT SCA CRITERIA FOR A BRIEF PERIOD AS THE
LOW MOVES BY.
LONG TERM...
THU NIGHT - FRI...SMALL CRAFT CONDITIONS ARE LIKELY.
&&
.FIRE WEATHER...
RAIN MOVING IN LATER TNGT THEN ENDING W TO E TUESDAY WILL PROVIDE
QPF OF 1/4 TO 1/2 INCH ACROSS MUCH OF THE REGION. DRY WX FOLLOWS
BRIEFLY TUESDAY EVE THEN MORE SHRA ACTIVITY MOVES IN FOR THE REST
OF THE WORK WEEK AS A FRONTAL SYSTEM FORMS AND REMAINS STAGNANT
OVER OR JUST S OF THE REGION...WITH THE BEST CHC FOR WIDESPREAD
SIGNIFICANT PRCP THURSDAY NGT THRU FRIDAY NGT. PRCP MOSTLY RA...
BUT SN OR MIXED RASN PSBL N/MT AREAS AND MAYBE EVEN FURTHER S LATE
IN THE WEEK. THE WET WX AND HIGH RH VALUES ALONG WITH FAIRLY WEAK
WINDS THRU FRIDAY SHOULD PROVIDE FOR VERY LOW FIRE DANGER.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CARIBOU ME
1235 PM EDT MON APR 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW
PRESSURE WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
1234 PM...MADE SOME MINOR TWEAKS TO THE SKY/TEMP/WIND GRIDS BASED
ON THE NOON EDT/16Z OBSERVATIONS AND THE LATEST SATELLITE
PICTURES.
920 AM UPDATE...HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY.
THE SKY RANGES FROM CLEAR ALONG THE COAST TO CLOUDY ACROSS MOST OF
NORTHERN MAINE. MADE SOME ADJUSTMENTS TO LOWER THE CLOUD COVER
THIS MORNING ALONG THE COAST. CLOUDS ACROSS THE NORTH WILL
GRADUALLY BREAK UP OVER THE NEXT FEW HOURS AS DRIER AIR AT MID
LEVELS (EVIDENT ON THE 12Z KCAR SOUNDING) BEGINS TO MIX INTO THE
LOWER LEVELS. ADJUSTED TEMPERATURES UP BY A FEW DEGREES ACROSS THE
NORTHERN ZONES WHERE A FEW SPOTS ARE ALREADY WITHIN A DEGREE OR
TWO OF FORECAST HIGHS. ALSO MADE SOME MINOR ADJUSTMENTS TO
INCREASE THE WIND GUSTS A BIT TODAY.
UPDATE 0717 EDT: HAVE ADJUSTED TEMPERATURE...NO OTHER CHANGES.
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /16Z MONDAY THROUGH FRIDAY/...
NEAR TERM: STILL LINGERING AREAS WITH MVFR CEILINGS ACROSS THE
NORTHERN TERMINALS. THE CLOUDS WILL THIN OUT THIS AFTERNOON WITH
ALL AREAS BECOMING VFR BY EALY-MID AFTERNOON. EXPECT VFR
CONDITIONS INTO TONIGHT...LOWERING TO IFR/MVFR TOWARD MORNING IN
RAIN AT THE SOUTHERN TERMINALS.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: THE WIND HAS DIMINISHED TO AROUND 10 KT AND THE SEAS
HAVE SUBSIDED TO UNDER 5 FT AND THEREFORE THE SCA WAS CANCELLED.
THE WIND AND SEAS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA
THROUGH TONIGHT.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...CB/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...CB/MIGNONE
MARINE...CB/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
921 AM EDT MON APR 8 2013
.SYNOPSIS...
HIGH PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW
PRESSURE WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
920 AM UPDATE...HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY.
THE SKY RANGES FROM CLEAR ALONG THE COAST TO CLOUDY ACROSS MOST OF
NORTHERN MAINE. MADE SOME ADJUSTMENTS TO LOWER THE CLOUD COVER
THIS MORNING ALONG THE COAST. CLOUDS ACROSS THE NORTH WILL
GRADUALLY BREAK UP OVER THE NEXT FEW HOURS AS DRIER AIR AT MID
LEVELS (EVIDENT ON THE 12Z KCAR SOUNDING) BEGINS TO MIX INTO THE
LOWER LEVELS. ADJUSTED TEMPERATURES UP BY A FEW DEGREES ACROSS THE
NORTHERN ZONES WHERE A FEW SPOTS ARE ALREADY WITHIN A DEGREE OR
TWO OF FORECAST HIGHS. ALSO MADE SOME MINOR ADJUSTMENTS TO
INCREASE THE WIND GUSTS A BIT TODAY.
UPDATE 0717 EDT: HAVE ADJUSTED TEMPERATURE...NO OTHER CHANGES.
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /13Z MONDAY THROUGH FRIDAY/...
NEAR TERM: MVFR AT THE NORTHERN TERMINALS SHOULD GIVE WAY TO VFR
BY EARLY THIS AFTERNOON. EXPECT VFR CONDITIONS INTO TONIGHT.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: THE WIND HAS DIMINISHED TO AROUND 10 KT AT THE EASTERN
MAINE SHELF. SEAS STILL RUNNING AT 6 FT WITH A 6 SEC PERIOD...SO
WILL MAINTAIN THE SCA FOR A COUPLE MORE HOURS. WAVE SYSTEM IS
FROM SOUTH-SOUTHWEST WITH SECONDARY LONGER PERIOD WAVE OUT OF
SOUTHEAST. SINCE PRIMARY WAVE GROUP WITH SOUTHWEST COMPONENT
EXPECT WAVES TO SUBSIDE SHORTLY AFTER WINDS LATER THIS MORNING SO
1500Z TIMING TO END SCA STILL LOOKS GOOD.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...CB/MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...CB/MIGNONE
MARINE...CB/MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
718 AM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW PRESSURE
WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE 0717 EDT: HAVE ADJUSTED TEMPERATURE...NO OTHER CHANGES.
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /11Z MONDAY THROUGH FRIDAY/...
NEAR TERM: EXPECT VFR CONDITIONS BY LATER THIS MORNING AND
CONTINUING VFR TONIGHT.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: FOR WINDS: HAVE BLENDED THE NAM12 AND GFS40 FOR
SUSTAIN WINDS AND WILL USE 125 PERCENT OF SUSTAINED WIND FOR GUST
SPEED. FOR WAVES: PRIMARY WAVE SYSTEM IS FROM SOUTH-SOUTHWEST WITH
SECONDARY LONGER PERIOD WAVE OUT OF SOUTHEAST. SINCE PRIMARY WAVE
GROUP WITH SOUTHWEST COMPONENT EXPECT WAVES TO SUBSIDE SHORTLY
AFTER WINDS LATER THIS MORNING SO 1500Z TIMING TO END SCA STILL
LOOKS GOOD.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS CARIBOU ME
429 AM EDT MON APR 8 2013
.SYNOPSIS...
LOW PRESSURE WILL BUILD ACROSS THE STATE LATE TODAY. LOW PRESSURE
WILL PASS TO THE SOUTH OF THE REGION TUESDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY. LOW PRESSURE IS
THEN EXPECTED TO APPROACH FROM THE GREAT LAKES TONIGHT. FOR POPS
AND QPF HAVE STARTED FORECAST PERIOD WITH RUC13 THEN TRANSITION TO
A BLEND OF THE NAM... GFS ...SREF AND ECMWF LATER THIS MORNING.
FOR SUSTAINED WINDS HAVE BLENDED THE NAM12 AND GMOS THEN USED 150
PERCENT OF THE SUSTAINED WINDS FOR GUSTS. TEMPERATURE AND DEW
POINT GRIDS GENERATED WITH THE NAM12.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
ACTIVE WEATHER PATTERN RIGHT INTO THE LONG TERM.
THE 1ST SYSTEM IN A SERIES OF EVENTS IS FCST TO AFFECT THE REGION
ON TUESDAY W/AN AREA OF LOW PRES MOVING OUT THE GREAT LAKES REGION
AND MOVING ACROSS SOUTHERN NH. THIS SYSTEM WILL DELIVER A ROUND OF
PRECIP TO THE CWA ON TUESDAY W/RAIN ACROSS THE CENTRAL AND DOWNEAST
REGION AND RAIN/SNOW ACROSS THE NORTHERN 3RD OF THE REGION. DECIDED
ON A BLEND OF THE NAM12 AND ECMWF FOR TEMPERATURES WHICH FAVORS A
COOLER SOLUTION THAN THE GFS40 OR CANADIAN GEM. THE LATEST ECMWF
AND NAM ARE HANDLING THE LATEST SETUP THIS MORNING QUITE WELL.
THE POPS ARE A BLEND OF THE NAM/ECMWF AND SREF WHICH SUPPORTS
60-80% POPS INTO TUESDAY AFTERNOON. QPF IS A BLEND OF THE SREF/HPC
AND NAM W/A MANUAL ADJUSTMENT FAVORING .25-.30" OF LIQUID PRECIP
MAINLY S OF CARIBOU AND PRESQUE ISLE. A COLD FRONT IS SHOWN BY THE
ECMWF AND NAM TO MOVE ACROSS THE AREA LATER TUESDAY NIGHT INTO
WEDNESDAY MORNING W/SOME WEAK CAA BEHIND THE FRONT PRECIP WILL
WIND DOWN TUESDAY EVENING AS THE BEST FORCING MOVES E OF THE CWA.
SOME PARTIAL CLEARING IS EXPECTED ACROSS THE INTERIOR DOWNEAST AND
THE COAST WHILE NORTHERN AND WESTERN AREAS WILL STAY MOSTLY CLOUDY
AS SUGGESTED BY THE LATEST NAM SOUNDINGS.THIS WILL HAVE A PLAY ON
OVERNIGHT TEMPERATURES TUESDAY NIGHT KEEPING THEM UP. THEREFORE,
ADJUSTMENTS WERE MADE TO TUESDAY NIGHT`S MINS FORM THE PREVIOUS
FORECAST TO BRING THEM UP A CATEGORY.
THE ASSOCIATED FRONTAL BOUNDARY WILL SLIDE TO THE EARLY WEDNESDAY
WHILE THE NEXT SYSTEM(WEAKER) IS SLATED TO MOVE ACROSS SOUTHERN
MAINE DURING THE DAY ON WEDNESDAY. THE BULK OF THE PRECIP IS FCST
TO BE SOUTH OF THE CAR CWA. THE BEST FORCING ESPECIALLY IN THE MID
LEVELS IS FCST TO BE ACROSS SOUTHERN AND SOUTHWESTERN MAINE. GIVEN
THIS SETUP, THE DECISION HERE WAS TO GO W/CHC POPS ON WEDNESDAY
W/THE HIGHEST PERCENTAGES ACROSS THE DOWNEAST AND COAST. STAYED
CLOSE TO THE DAYCREW`S MAXES ON WEDNESDAY W/BELOW NORMAL READINGS
FOR APRIL. THE CHALLENGE COMES IN THE LONGER RANGE BELOW.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
CHALLENGING FCST ESPECIALLY LATER IN THE WEEK INTO EARLY WEEKEND.
THE LATEST RUNS OF THE ECMWF AND THE GFS40 SHOW CAA COMING IN
BEHIND THE DEPARTING FRONTAL BOUNDARY WEDNESDAY NIGHT W/STRONG
CANADIAN HIGH PRES NOSING DOWN FROM JAMES BAY. THE 12Z & 00Z RUNS
OF THE ECMWF REMAIN CONSISTENT W/BRINGING 925MBS TEMPS DOWN TO -10
TO -12 C ACROSS THE NORTHERN 1/2 OF THE CWA AND EVEN -4 TO -8C AS
FAR SOUTH AS BHB BY 12Z THURSDAY. THE LATEST RUN OF THE GFS40 IS
COLDER THAN ITS PREVIOUS RUNS SIMILAR THE ECMWF. SOME THE 00Z
ENSEMBLE MEMBER SUPPORT THIS SETUP AS WELL. THIS COULD LEAD TO AN
INTERESTING FCST FOR FRIDAY INTO SATURDAY AS LOW PRES IS SHOWN TO
COME OUT OF THE OHIO VALLEY AND INTO NEW ENGLAND. COLD AIR IN
PLACE W/THE HIGH TO THE NORTH COULD ALLOW FOR A WEDGE TYPE(COLD
AIR DAMMING) SETUP W/A POTENTIAL FOR PRECIP BEING IN THE FORM OF
SNOW AS FAR SOUTH AS THE BANGOR REGION. THE ECMWF IS COLDER THAN
THE GFS AND ITS ENSEMBLE MEAN ENHANCING THE COLDER ENTRENCHED INTO
THE REGION. THE 00Z RUN OF THE CANADIAN GLOBAL WAS WARMER AND ATTM
APPEARED TO BE THE OUTLIER. GIVEN THIS IS DAY 5-6 AND CONFIDENCE
FOR TEMPERATURES NOT HIGH, DECIDED TO STAY CLOSER TO THE
DAYCREW`S ASSESSMENT OF A SLIGHTLY WARMER SOLUTION SHOWING
SNOW/RAIN ACROSS THE NORTH AND SNOW GOING TO RAIN FOR CENTRAL AND
DOWNEAST AREAS. MAJOR ADJUSTMENTS WERE MADE TO THE POPS BRINGING
THEM UP TO LIKELY(60-70%) AS CONFIDENCE IS HIGH THE REGION WILL
SEE PRECIP W/PRECIP TYPE STILL IN QUESTION ATTM. THIS MATCHES WELL
W/GYX AS WELL. LATER RUNS WILL HOPEFULLY SHOW MORE CONTINUITY. AT
ANY RATE, BELOW NORMAL DAYTIME HIGHS LOOK TO BE THE RULE INTO THE
WEEKEND.
&&
.AVIATION /08Z MONDAY THROUGH FRIDAY/...
NEAR TERM: EXPECT VFR CONDITIONS BY LATER THIS MORNING AND
CONTINUING VFR TONIGHT.
SHORT TERM: MVFR TO IFR CONDITION FOR ALL TERMINALS ON TUESDAY
W/SOME IMPROVEMENT TO VFR FOR KBGR AND KBHB TUESDAY NIGHT INTO
EARLY WEDNESDAY. THE NORTHERN TERMINALS WILL STAY W/MVFR A WHILE
LONGER INTO TUESDAY NIGHT. KBGR AND KBHB HAVE THE POTENTIAL TO GO
MVFR ON WEDNESDAY AFTERNOON AS WEAK LOW PRES PASSES BY TO THE
SOUTH. NORTHERN TERMINALS LOOK TO GO VFR. THE CHALLENGE COMES ON
LATER THURSDAY INTO FRIDAY AS LOW PRES APCHS FROM THE SW BRINGING
MVFR AND IFR CONDITIONS.
&&
.MARINE...
NEAR TERM: FOR WINDS: HAVE BLENDED THE NAM12 AND GFS40 FOR
SUSTAIN WINDS AND WILL USE 125 PERCENT OF SUSTAINED WIND FOR GUST
SPEED. FOR WAVES: PRIMARY WAVE SYSTEM IS FROM SOUTH-SOUTHWEST WITH
SECONDARY LONGER PERIOD WAVE OUT OF SOUTHEAST. SINCE PRIMARY WAVE
GROUP WITH SOUTHWEST COMPONENT EXPECT WAVES TO SUBSIDE SHORTLY
AFTER WINDS LATER THIS MORNING SO 1500Z TIMING TO END SCA STILL
LOOKS GOOD.
SHORT TERM: NO HEADLINES ANTICIPATED FOR EARLY PART OF THIS TERM AS
WINDS AND SEAS ARE FCST TO REMAIN BELOW SCA. A BLEND OF THE NAM12
AND GFS40 WAS USED FOR THE SUSTAINED WINDS WHICH LEADS TO 10-15
KTS INTO THURSDAY. SEAS ARE EXPECTED TO BE 3-5 FT AT BEST. THE
CHANGE IS EXPECTED THURSDAY NIGHT INTO FRIDAY AS WINDS/SEAS COULD
INCREASE AHEAD OF THE NEXT SYSTEM MENTIONED IN THE LONG TERM
SECTION ABOVE.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT THIS MORNING FOR
ANZ050>052.
&&
$$
NEAR TERM...MIGNONE
SHORT TERM...HEWITT
LONG TERM...HEWITT
AVIATION...MIGNONE
MARINE...MIGNONE/HEWITT
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
706 PM EDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 438 PM EDT MON APR 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
TROUGH OVER NORTHERN LOWER MICHIGAN WHICH SUPPORTED A
DEFORMATION/FGEN BAND OF PCPN (RAIN/SLEET) OVER CNTRL UPPER MI ON
ITS NORTHWEST FLANK. RADAR INDICATED THAT THE BAND WAS MOVING
STEADILY OFF TO THE ENE WHICH SHOULD BRING AN END TO THE PCPN OVER
CNTRL UPPER MI BY LATE AFTERNOON AND OVER THE ERN CWA THIS EVENING.
AT THE SFC...THE MAIN FRONTAL BOUNDARY STRETCHED FROM NRN IA INTO SRN
LOWER MI. EASTERLY FLOW PREVAILED ACROSS UPPER MI AHEAD OF AN
INVERTED TROUGH OVER ERN MN.
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION AREAS
OF FOG ARE EXPECTED. WEAK ENE TO NE UPSLOPE...STILL MAY SUPPORT SOME
-DZ/-FZDZ OVERNIGHT OVER THE NORTH. THE CLOUDS SHOULD BE THICK
ENOUGH TO KEEP TEMPS TOWARD THE HIGHER END OF GUIDANCE...AROUND 30.
ANOTHER AREA OF PCPN DEVELOPING OVER THE PLAINS IS EXPECTED TO
SPREAD INTO THE WESTERN GREAT LAKES AS THE AREA FALLS UNDER THE
RIGHT ENTRANCE OF AN UPPER LEVEL JET STREAK MOVING THROUGH NRN
ONTARIO INTO QUEBEC. A BROAD AREA OF ISENTROPIC LIFT NORTH OF THE
WARM FRONT WILL BRING THE EXPANDING PCPN THROUGH WI TOWARD UPPER MI
BY MIDDAY TUE. ALTHOUGH THE MODELS HAVE TRENDED A BIT FARTHER NORTH
WITH THE PCPN AREA...EXPECT THAT THERE MAY STILL BE A SHARP NRN EDGE
TO THE PCPN THROUGH UPPER MI GIVEN THE DRIER ACYC NRLY 850-700 FLOW
FROM NRN ONTARIO INTO THE AREA. SO...POPS WERE TAPERED OFF
SIGNIFICANTLY FROM SOUTH TO NORTH. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET WILL BE POSSIBLE...EXCEPT OVER THE FAR SOUTH WHERE
SFC TEMPS CLIMB INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 PM EDT MON APR 8 2013
A 500MB RIDGE WILL BE OVERHEAD TUESDAY NIGHT THROUGH THURSDAY
MORNING. HOWEVER...WITH SIZABLE LOWS TO OUR NORTH AND
SOUTHWEST...SIGNIFICANT WEATHER WILL BE NEARBY.
850MB TEMPS 0F -1 TO -4C TUESDAY NIGHT...AND A GOOD FEED OF MOISTURE
INTO S CENTRAL UPPER MICHIGAN WILL KEEP A CHANCE OF PRECIPITATION IN
THE AREA. WHILE THE LOWEST LEVELS BELOW 900MB SHOULD BE FAIRLY
SATURATED...BOTH THE NAM AND GFS INDICATE A LAYER OF DRY AIR AROUND
800-850MB...WITH MOISTURE ABOVE THAT LAYER REACHING THE DGZ WHICH
SHOULD BE HOVERING NEAR 500MB. SFC TEMPS NEAR OR SLIGHTLY BELOW
FREEZING DOES NOT MAKE THIS FORECAST ANY EASIER. AT THIS
POINT...WITH THE LACK OF DEPTH TO THE THIN DRY LAYER...IT STILL
LOOKS LIKE SNOW WILL BE THE BEST BET. THE BEST CHANCE OF SNOW WILL
REMAIN SOUTH. IF THE NAM IS RIGHT THOUGH...THERE WILL BE NEARLY
CONSTANT SLEET FROM LATE TUESDAY NIGHT THROUGH AT LEAST THURSDAY.
THE 500MB RIDGE WILL BE PUSHED EAST ON THURSDAY...WITH STRONGER E-NE
WINDS /40-55KTS AT 850MB/ AND POTENTIALLY MERGING SOUTHERN AND
NORTHERN STREAM SYSTEMS. WHILE THE 08/12Z GFS INDICATES MORE OF A
MERGER...THE 12/00Z ECMWF PUSHES THE NORTHERN LOW OFF THE EASTERN
COAST OF CANADA BEFORE THE LOW FROM THE CENTRAL PLAINS CAN MOVE
ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT INTO FRIDAY. THE ECMWF
LOOKS TO BE A BIT ON ITS OWN AT THIS POINT WITH THE 500MB LOW
SPINNING ACROSS UPPER MICHIGAN FRIDAY AND FRIDAY NIGHT...BEFORE
SLIDING EAST. THE CANADIAN AND GFS ARE MORE PROGRESSIVE WITH THE
FEATURE.
NO MATTER WHAT SOLUTION...OR GROUP OF SOLUTIONS IS PREFERRED...IT
LOOKS LIKE HEADLINE WORTHY SNOW WILL BE PUSHING BACK IN. CURRENTLY
HAVE AN INITIAL FORECAST OF NEAR HALF AN INCH OF LIQUID FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING...EQUATING TO 6 OR MORE
INCHES OF HEAVY WET SNOW FOR AREAS SOUTHWEST OF A LINE FROM
ONTONAGON TO SIDNAW AND IRON MOUNTAIN. GIVEN THE FAVORABLE UPSLOPE
FLOW...INCREASED POPS AND QPF FOR THE HIGHER ELEVATIONS OF WESTERN
BARAGA TO EASTERN MARQUETTE COUNTY NEAR LAKE SUPERIOR. COLDER AIR
/850MB TEMPS OF -10C OR COOLER/ WILL LIKELY SLIDE IN FROM DAYBREAK
FRIDAY ON. THE ECMWF HAS ANOTHER HALF INCH TO THREE QUARTERS OF
LIQUID NOT INCLUDED IN THE ABOVE TOTALS...WITH THE MORE WRAPPED UP
AND SLOWER SOLUTION. WILL NEED TO WAIT UNTIL MODELS COME IN BETTER
AGREEMENT BEFORE MAKING ANY MORE CRITICAL EVALUATIONS.
ALL SEEMS TO RIGHT WITH THE WORLD AGAIN BRIEFLY SATURDAY
AFTERNOON...WITH THE MODELS IN BETTER AGREEMENT. EXPECT THE 500MB
LOW TO BE NEAR THE ONTARIO/QUEBEC BORDER...WITH RIDGING ACROSS
MINNESOTA PUSHING INTO WESTERN UPPER MICHIGAN. THIS IS SHORT
LIVED...AS THE GFS AND ECMWF COME OUT OF PHASE AGAIN BY SUNDAY
THANKS TO THE SLOWER ECMWF SOLUTION. GIVEN THE SIGNIFICANT
UNCERTAINTY FOR SATURDAY NIGHT THROUGH THE END OF THE FORECAST
PERIOD...FEW LARGE SCALE CHANGES WILL BE MADE TO DEVIATE FROM THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z TUESDAY EVENING)
ISSUED AT 706 PM EDT MON APR 8 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
LIFR/VLIFR CONDITIONS WILL PERSIST THROUGH TUE MORNING AT ALL SITES.
AS DRIER AIR TRIES TO COME IN TUE MORNING AT CMX AND
IWD...CONDITIONS WILL IMPROVE TO VFR. AT SAW...LOW LEVEL MOISTURE
WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO KEEP THE LOW CIGS IN
THROUGH THE REST OF THE FORECAST PERIOD. AT CMX...TEMPERATURES ARE
COLD ENOUGH FOR A LITTLE FREEZING DRIZZLE OVERNIGHT.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT MON APR 8 2013
A WEAK TROUGH WILL MOVE INTO LAKE SUPERIOR TONIGHT WITH MAINLY LIGHT
WINDS. FROM TUESDAY 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 NE WINDS TO AROUND
25 KT TUE AND AT OR ABOVE 25 KTS TOWARD MID WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
439 PM EDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 438 PM EDT MON APR 8 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A WELL-DEFINED SHORTWAVE
TROUGH OVER NORTHERN LOWER MICHIGAN WHICH SUPPORTED A
DEFORMATION/FGEN BAND OF PCPN (RAIN/SLEET) OVER CNTRL UPPER MI ON
ITS NORTHWEST FLANK. RADAR INDICATED THAT THE BAND WAS MOVING
STEADILY OFF TO THE ENE WHICH SHOULD BRING AN END TO THE PCPN OVER
CNTRL UPPER MI BY LATE AFTERNOON AND OVER THE ERN CWA THIS EVENING.
AT THE SFC...THE MAIN FRONTAL BOUNDARY STRETCHED FROM NRN IA INTO SRN
LOWER MI. EASTERLY FLOW PREVAILED ACROSS UPPER MI AHEAD OF AN
INVERTED TROUGH OVER ERN MN.
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE ACROSS THE REGION AREAS
OF FOG ARE EXPECTED. WEAK ENE TO NE UPSLOPE...STILL MAY SUPPORT SOME
-DZ/-FZDZ OVERNIGHT OVER THE NORTH. THE CLOUDS SHOULD BE THICK
ENOUGH TO KEEP TEMPS TOWARD THE HIGHER END OF GUIDANCE...AROUND 30.
ANOTHER AREA OF PCPN DEVELOPING OVER THE PLAINS IS EXPECTED TO
SPREAD INTO THE WESTERN GREAT LAKES AS THE AREA FALLS UNDER THE
RIGHT ENTRANCE OF AN UPPER LEVEL JET STREAK MOVING THROUGH NRN
ONTARIO INTO QUEBEC. A BROAD AREA OF ISENTROPIC LIFT NORTH OF THE
WARM FRONT WILL BRING THE EXPANDING PCPN THROUGH WI TOWARD UPPER MI
BY MIDDAY TUE. ALTHOUGH THE MODELS HAVE TRENDED A BIT FARTHER NORTH
WITH THE PCPN AREA...EXPECT THAT THERE MAY STILL BE A SHARP NRN EDGE
TO THE PCPN THROUGH UPPER MI GIVEN THE DRIER ACYC NRLY 850-700 FLOW
FROM NRN ONTARIO INTO THE AREA. SO...POPS WERE TAPERED OFF
SIGNIFICANTLY FROM SOUTH TO NORTH. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET WILL BE POSSIBLE...EXCEPT OVER THE FAR SOUTH WHERE
SFC TEMPS CLIMB INTO THE UPPER 30S.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 422 PM EDT MON APR 8 2013
A 500MB RIDGE WILL BE OVERHEAD TUESDAY NIGHT THROUGH THURSDAY
MORNING. HOWEVER...WITH SIZABLE LOWS TO OUR NORTH AND
SOUTHWEST...SIGNIFICANT WEATHER WILL BE NEARBY.
850MB TEMPS 0F -1 TO -4C TUESDAY NIGHT...AND A GOOD FEED OF MOISTURE
INTO S CENTRAL UPPER MICHIGAN WILL KEEP A CHANCE OF PRECIPITATION IN
THE AREA. WHILE THE LOWEST LEVELS BELOW 900MB SHOULD BE FAIRLY
SATURATED...BOTH THE NAM AND GFS INDICATE A LAYER OF DRY AIR AROUND
800-850MB...WITH MOISTURE ABOVE THAT LAYER REACHING THE DGZ WHICH
SHOULD BE HOVERING NEAR 500MB. SFC TEMPS NEAR OR SLIGHTLY BELOW
FREEZING DOES NOT MAKE THIS FORECAST ANY EASIER. AT THIS
POINT...WITH THE LACK OF DEPTH TO THE THIN DRY LAYER...IT STILL
LOOKS LIKE SNOW WILL BE THE BEST BET. THE BEST CHANCE OF SNOW WILL
REMAIN SOUTH. IF THE NAM IS RIGHT THOUGH...THERE WILL BE NEARLY
CONSTANT SLEET FROM LATE TUESDAY NIGHT THROUGH AT LEAST THURSDAY.
THE 500MB RIDGE WILL BE PUSHED EAST ON THURSDAY...WITH STRONGER E-NE
WINDS /40-55KTS AT 850MB/ AND POTENTIALLY MERGING SOUTHERN AND
NORTHERN STREAM SYSTEMS. WHILE THE 08/12Z GFS INDICATES MORE OF A
MERGER...THE 12/00Z ECMWF PUSHES THE NORTHERN LOW OFF THE EASTERN
COAST OF CANADA BEFORE THE LOW FROM THE CENTRAL PLAINS CAN MOVE
ACROSS THE UPPER GREAT LAKES THURSDAY NIGHT INTO FRIDAY. THE ECMWF
LOOKS TO BE A BIT ON ITS OWN AT THIS POINT WITH THE 500MB LOW
SPINNING ACROSS UPPER MICHIGAN FRIDAY AND FRIDAY NIGHT...BEFORE
SLIDING EAST. THE CANADIAN AND GFS ARE MORE PROGRESSIVE WITH THE
FEATURE.
NO MATTER WHAT SOLUTION...OR GROUP OF SOLUTIONS IS PREFERRED...IT
LOOKS LIKE HEADLINE WORTHY SNOW WILL BE PUSHING BACK IN. CURRENTLY
HAVE AN INITIAL FORECAST OF NEAR HALF AN INCH OF LIQUID FROM
WEDNESDAY NIGHT THROUGH THURSDAY EVENING...EQUATING TO 6 OR MORE
INCHES OF HEAVY WET SNOW FOR AREAS SOUTHWEST OF A LINE FROM
ONTONAGON TO SIDNAW AND IRON MOUNTAIN. GIVEN THE FAVORABLE UPSLOPE
FLOW...INCREASED POPS AND QPF FOR THE HIGHER ELEVATIONS OF WESTERN
BARAGA TO EASTERN MARQUETTE COUNTY NEAR LAKE SUPERIOR. COLDER AIR
/850MB TEMPS OF -10C OR COOLER/ WILL LIKELY SLIDE IN FROM DAYBREAK
FRIDAY ON. THE ECMWF HAS ANOTHER HALF INCH TO THREE QUARTERS OF
LIQUID NOT INCLUDED IN THE ABOVE TOTALS...WITH THE MORE WRAPPED UP
AND SLOWER SOLUTION. WILL NEED TO WAIT UNTIL MODELS COME IN BETTER
AGREEMENT BEFORE MAKING ANY MORE CRITICAL EVALUATIONS.
ALL SEEMS TO RIGHT WITH THE WORLD AGAIN BRIEFLY SATURDAY
AFTERNOON...WITH THE MODELS IN BETTER AGREEMENT. EXPECT THE 500MB
LOW TO BE NEAR THE ONTARIO/QUEBEC BORDER...WITH RIDGING ACROSS
MINNESOTA PUSHING INTO WESTERN UPPER MICHIGAN. THIS IS SHORT
LIVED...AS THE GFS AND ECMWF COME OUT OF PHASE AGAIN BY SUNDAY
THANKS TO THE SLOWER ECMWF SOLUTION. GIVEN THE SIGNIFICANT
UNCERTAINTY FOR SATURDAY NIGHT THROUGH THE END OF THE FORECAST
PERIOD...FEW LARGE SCALE CHANGES WILL BE MADE TO DEVIATE FROM THE
ONGOING FORECAST.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 151 PM EDT MON APR 8 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PALCE AND UPSLOPE EASTERLY FLOW
CONTINUING THIS AFTERNOON...EXPECT VLIFR CONDITION WILL PERSIST AT
CMX INTO TONIGHT. SOME IMPROVEMENT MAY BE POSSIBLE LATE TONIGHT INTO
TUE MORNING WHEN WINDS BECOME NNW REDUCING THE UPSLOPE COMPONENT.
AT SAW...RAIN MIXED WITH SNOW AND EAST WINDS SHOULD ALSO DROP
CONDITIONS TO IFR THIS AFTERNOON AND TO LIFR LATE THIS AFTERNOON OR
EVENING. E WINDS VEERING N SHOULD KEEP CONDITIONS FROM IMPROVING
MUCH TIL TUE MORNING.
AT IWD...ENOUGH LOW LEVEL MOISTURE WILL LINGER OVER THE AREA SO THAT
MVFR CIGS ARE EXPECTED TO FALL TO IFR THIS AFTERNOON AND TONIGHT AS WINDS
BECOME NORTHERLY.
&&
.MARINE...(FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 438 PM EDT MON APR 8 2013
A WEAK TROUGH WILL MOVE INTO LAKE SUPERIOR TONIGHT WITH MAINLY LIGHT
WINDS. FROM TUESDAY 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 NE WINDS TO AROUND
25 KT TUE AND AT OR ABOVE 25 KTS TOWARD MID WEEK.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
345 PM EDT MON APR 8 2013
.SYNOPSIS...
ISSUED AT 345 PM EDT MON APR 8 2013
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS CAN BE EXPECTED THIS
WEEK AS AN ACTIVE FRONTAL BOUNDARY REMAINS NEARLY STATIONARY JUST
SOUTH OF MICHIGAN. WIDESPREAD RAINFALL AMOUNTS OF THREE OR MORE
INCHES ARE POSSIBLE BY THE END OF THE WEEK.
A THREAT FOR FREEZING RAIN... SLEET AND SNOW WILL ALSO DEVELOP
WEDNESDAY NIGHT AND LINGER THROUGH FRIDAY... MAINLY ALONG AND NORTH
OF THE INTERSTATE 96 CORRIDOR... AS COLD AIR ASSOCIATED WITH A
CANADIAN HIGH PRESSURE AREA COMES DOWN FROM THE NORTH.
&&
.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY NIGHT)
ISSUED AT 345 PM EDT MON APR 8 2013
WIND ADVISORY REMAINS IN EFFECT UNTIL 8 PM. THE CENTER OF THE
COMPACT/IMPRESSIVE SFC LOW WAS NEAR MKG AT 3 PM AND EVEN HAS AN
"EYE" ASSOCIATED WITH IT ON VISIBLE SATELLITE IMAGERY. RUC RAPID
REFRESH HAS BEEN SHOWING SFC WIND GUSTS TO 45 MPH ALONG AND SOUTH OF
THE I-96 CORRIDOR THROUGH EARLY EVENING ON THE SRN PERIPHERY OF THIS
SFC LOW. SFC TEMPS IN THE MID 60S IN THE WARM SECTOR COMBINED WITH
PARTIAL CLEARING WILL YIELD DEEPER MIXING TO BRING THE STRONG GUSTS
DOWN TO THE SFC. THE SHOWER THREAT WITH THIS INITIAL WAVE WAS
ENDING/EXITING TO THE NORTHEAST THIS AFTERNOON. TONIGHT SHOULD BE
MOSTLY DRY IN THE SUBSIDENCE BEHIND IT.
MOIST GROUND LEFT OVER BY THIS MORNINGS RAIN COMBINED WITH
DIMINISHING WINDS AND PERIOD OF DECREASING CLOUDS WILL BRING THE
POTENTIAL FOR AREAS OF FOG LATER TONIGHT. CLOUDS SHOULD BE
INCREASING AGAIN THOUGH AHEAD OF THE NEXT APCHG WAVE TOWARD DAYBREAK.
WILL CARRY CATEGORICAL POPS IN ALL FCST PERIODS FROM TUESDAY THROUGH
WEDNESDAY NIGHT AS FAVORABLE WET SYNOPTIC PATTERN PERSISTS. WE
CONTINUE TO BE IN THE RIGHT ENTRANCE REGION OF THE 150 KT UPR JET
CORE IN SRN CANADA... WITH STRONG MID LEVEL FGEN FORCING ALONG A
VERY TIGHT BAROCLINIC ZONE. ELEVATED INSTABILITY AND A PERSISTENT
40+ KT LOW LEVEL JET EAST OF THE DEEP LONGWAVE TROUGH OVER THE WRN
U.S. SHOULD RESULT IN PERIODS OF POTNL TSTMS AS WELL.
SVR WX THREAT REMAINS VERY LOW SINCE THE SFC BOUNDARY REMAINS MOSTLY
SOUTH OF MI. HOWEVER SOME EPISODES OF SMALL HAIL AND/OR LOCALLY
HEAVY
RAINFALL ARE CERTAINLY POSSIBLE. FEEL NO NEED FOR ANY FLOOD
HEADLINES IN THE SHORT TERM GIVEN THE RECENT DRY CONDITIONS... BUT
NUISANCE FLOODING COULD BECOME AN ISSUE BY MID WEEK DEPENDING ON HOW
MUCH RAIN WE SEE FROM THE NEXT FEW WAVES.
FREEZING RAIN/SLEET/SNOW BECOMES A CONCERN BY LATE WEDNESDAY NIGHT
IN
THE NRN CWFA AS THE COLD LOW LEVEL AIR MASS ASSOCIATED WITH THE
HUDSON BAY HIGH STARTS TO INFILTRATE THE REGION FROM THE NORTHEAST.
.LONG TERM...(THURSDAY THROUGH MONDAY)
ISSUED AT 345 PM EDT MON APR 8 2013
UNSETTLED WX WILL CONTINUE THURSDAY AS THE SLOW MOVING LOW PRESSURE
SYSTEM CONTINUES TO IMPACT OUR REGION. RAIN IS EXPECTED NEAR TO
SOUTH OF I-96 THURSDAY AND THERE IS POTENTIAL FOR A RAIN SNOW MIX
ACROSS OUR NORTHERN COUNTIES THURSDAY WITH NE FLOW CAA WITH HIGH
PRESSURE OVER JAMES BAY.
NE TO NORTH FLOW CAA ACROSS OUR AREA THURSDAY NIGHT WILL RESULT IN
POTENTIAL FOR LIGHT SNOW OR A LIGHT RAIN/LIGHT SNOW MIX. ALSO CANNOT
RULE OUT SOME (LIGHT) FREEZING RAIN THURSDAY EVENING GIVEN THIS
SYNOPTIC SETUP WITH THE HIGH PRESSURE TO OUR NORTH AND SHALLOW LOW
LEVEL COLD AIR IN PLACE.
SOME LIGHT PCPN MAY EVEN LINGER INTO FRIDAY BEFORE A MORE TRANQUIL
WX PATTERN FINALLY DEVELOPS FRIDAY NIGHT THROUGH THE WEEKEND AS HIGH
PRESSURE BUILDS IN. TEMPS WILL COOL TO AROUND TEN DEGREES BELOW
NORMAL ON THE BACK SIDE OF THAT LOW PRESSURE SYSTEM LATE THURSDAY
THROUGH SATURDAY BEFORE RETURNING TO CLOSER TO NORMAL BY LATE IN THE
WEEKEND INTO EARLY NEXT WEEK.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY)
ISSUED AT 1230 PM EDT MON APR 8 2013
WINDY CONDITIONS ARE EXPECTED TO DEVELOP AT MOST OF THE TERMINALS
DURING THE MID TO LATE AFTERNOON HOURS AS SOME PARTIAL CLEARING
DEVELOPS AND ALLOWS FOR WIND GUSTS TO POTENTIALLY REACH 40 TO 45 KTS
MID TO LATE AFTERNOON OUT OF THE SOUTH TO SOUTHWEST. WIND SPEEDS
WILL DIMINISH QUICKLY EARLY THIS EVENING.
IFR/MVFR CONDITIONS ARE ANTICIPATED THIS AFTERNOON WITH SCATTERED
SHOWERS. CONDITIONS WILL GRADUALLY DETERIORATE TO IFR/LIFR LATE
TONIGHT AS PARTIAL CLEARING AND ALL THE MOISTURE FROM RAINFALL
EARLIER TODAY ALLOWS FOG TO DEVELOP.
CONDITIONS WILL REMAIN IFR/LIFR TUESDAY MORNING WITH RAIN
OVERSPREADING ALL THE TERMINALS FROM SW TO NE DURING THE MID TO LATE
MORNING HOURS.
&&
.MARINE...
ISSUED AT 345 PM EDT MON APR 8 2013
SMALL BUT STRONG AREA OF LOW PRESSURE MOVING FROM MUSKEGON TO THE
SAGINAW BAY THROUGH EARLY EVENING WILL BRING PERIOD OF STRONG/GUSTY
WESTERLY WINDS MAINLY SOUTH OF WHITEHALL. WINDS/WAVES SUBSIDING
QUICKLY AFTER 8 PM. AFTER THIS EVENING... WINDS WILL BE MOSTLY
OFFSHORE THROUGH THE WEEK BUT STILL STRONG AT TIMES.
&&
.HYDROLOGY...
ISSUED AT 345 PM EDT MON APR 8 2013
THE WAVE THIS MORNING PRODUCED AROUND ONE HALF INCH OF RAIN WHICH IS
NOT ENOUGH TO CAUSE ANY HYDRO ISSUES. HOWEVER THE POTENTIAL EXISTS
FOR ANOTHER THREE OR MORE INCHES OF RAIN THROUGH THE END OF THE WEEK
AND THE HYDRO SITUATION WILL NEED TO BE CLOSELY MONITORED.
FORTUNATELY THE RIVERS ARE EXTREMELY LOW RIGHT NOW AND CAN HANDLE
QUITE A BIT OF RAINFALL... ESPECIALLY IF IT IS SPACED OUT OVER
SEVERAL DAYS. THE REALITY OF IT IS THAT WE REALLY NEED ALL THIS RAIN
TO GET THE RIVERS OUT OF NEAR RECORD LOW STAGES.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...WIND ADVISORY UNTIL 8 PM EDT THIS EVENING FOR MIZ050-056>059-
064>067-071>074.
LM...SMALL CRAFT ADVISORY UNTIL 9 PM EDT THIS EVENING FOR LMZ844>848.
&&
$$
SYNOPSIS...MEADE
SHORT TERM...MEADE
LONG TERM...LAURENS
AVIATION...LAURENS
HYDROLOGY...MEADE
MARINE...MEADE
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
757 PM CDT TUE APR 9 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 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 651 PM CDT TUE APR 9 2013
MAIN CONCERN THIS FORECAST PERIOD IS THE TIMING OF PRECIPITATION
AHEAD OF A STRONG SPRING STORM SYSTEM. CURRENTLY EXPECT TAF SITES
TO REMAIN DRY THROUGH THIS EVENING...THOUGH AS THE LLJ RAMPS UP
AHEAD OF THE ADVANCING SYSTEM OVERNIGHT TONIGHT...COULD SEE SOME
WARM ADVECTION DRIVEN PRECIPITATION POP UP...PRIMARILY AFFECTING
KCOU AND KUIN BY THE 08-09Z TIME FRAME. KUIN...GIVEN ITS PROXIMITY
TO AN EAST- WEST FRONTAL ZONE...HAS THE GREATEST CHANCE TO SEE
PRECIPITATION OVERNIGHT TONIGHT. AS ASCENT CONTINUES TO INCREASE
AHEAD OF THE APPROACHING COLD FRONT...EXPECT A BAND OF
PRECIPITATION TO TREK EASTWARD ACROSS THE AREA DURING THE LATE
OVERNIGHT AND EARLY MORNING HOURS...IMPACTING METRO TAF SITES BY
AROUND 12Z. A LATE MORNING/EARLY AFTERNOON LULL LOOKS TO BE A
POSSIBILITY PRIOR TO THE MAIN LINE OF STORMS EXPECTED AHEAD OF THE
FRONT LATE WEDNESDAY AFTERNOON AND INTO WEDNESDAY EVENING...WITH
MVFR CONDITIONS EXPECTED AND IFR POSSIBLE WITH SOME OF THE
STRONGER STORMS.
SPECIFICS FOR KSTL...
DRY AND VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THE OVERNIGHT
HOURS WITH CONTINUED STRONG SOUTHERLY FLOW. A LINE OF WARM
ADVECTION DRIVEN PRECIPITATION COULD DEVELOP AHEAD OF THE MAIN
SYSTEM TONIGHT...AND MAKE IT TO KSTL BY AROUND 12Z. THE TIMING OF
THE PRECIPITATION REMAINS THE BIGGEST CHALLENGE WITH THIS TAF
PACKAGE...AND BEST THINKING IS REFLECTED IN THE TAF AT THIS TIME.
EXPECT A LULL FROM LATE MORNING THROUGH EARLY AFTERNOON PRIOR TO
THE MAIN LINE OF SHOWERS AND THUNDERSTORMS MOVING EASTWARD DURING
THE EVENING HOURS ON WEDNESDAY. MVFR CONDITIONS ARE EXPECTED WITH
THUNDERSTORMS WITH IFR POSSIBLE WITH SOME OF THE STRONGER STORMS.
WINDS WILL REMAIN SOUTHERLY UNTIL WEDNESDAY EVENING BEFORE VEERING
TO THE WEST AND EVENTUALLY NORTHWEST AS THE FRONT MOVES THROUGH AT
THE END OF THE VALID PERIOD.
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 ST LOUIS MO
345 PM CDT MON APR 8 2013
.SHORT TERM...(TONIGHT THROUGH TUESDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE BOUNDARY LAYER HAS CONTINUED TO MOISTEN TODAY WITH SURFACE DEW
POINTS CURRENTLY IN THE MID 50S TO LOWER 60S. THIS MOISTURE COMBINED
WITH HEATING HAS RESULTED IN MODEST INSTABILITY WITH SBCAPES OF
AROUND 1200-1700 J/KG. SPC MESOANALYSIS SHOWS THERE IS ONLY WEAK
CIN ACROSS THE NRN 2/3RDS OF THE CWA AND MOST OF THE REGION HAS
EXTENSIVE CU. DESPITE THIS...THE APPARENT LACK OF A LOW LEVEL
FORCING MECHANISM/BOUNDARY HAS INHIBITED CONVECTION. MODEL QPFS
ARE OF LITTLE USE EARLY IN THE PERIOD OWING TO OVERDONE SURFACE
DEW POINTS AND INSTABILITY AND CONVECTIVE PCPN WITHIN THE MODELS.
THIS INCLUDES THE EXPLICIT CONVECTION ALLOWING MODELS. THE LATEST
SATELLITE IMAGERY SUGGESTS THE DEEPEST AND MOST AGITATED CU FIELD
RESIDES ACROSS NORTHERN MO INTO WEST CENTRAL IL AND THIS IS WHERE
THE HIGHEST POPS WILL BE FORECAST THIS EVENING. WATER VAPOR
IMAGERY AND THE RUC SHOWS SOME MINOR MID LEVEL PURTURBATIONS
UPSTREAM ACROSS THE PLAINS WHICH WILL SKIRT THIS REGION LATER
TONIGHT AND THUS NORTHERN MO INTO WEST CENTRAL IL WILL HAVE THE
HIGHEST POPS OVERNIGHT AS WELL. OVERNIGHT LOWS WILL BE QUITE MILD.
TUESDAY IS EXPECTED TO BE LARGELY DRY. THERE COULD BE SOME
RESIDUAL SHOWERS AND THUNDERSTORMS ACROSS THE FAR NORTHERN CWA IN
THE MORNING...HOWEVER THE ABSENCE OF A FOCUSING BOUNDARY AND A
STRENGTHENING EML SUGGESTS ANY OTHER CONVECTIVE POTENTIAL WILL BE
QUITE LOW AND ISOLATED. MORE IMPORTANTLY WE WILL SEE YET ANOTHER
DAY OF SEASONABLY WARM TEMPERATURES. DESPITE A GOOD DEAL OF
CU...HIGHS SHOULD RISE INTO MID 70S TO LOWER 80S.
GLASS
.LONG TERM...(TUESDAY THROUGH NEXT MONDAY)
ISSUED AT 334 PM CDT MON APR 8 2013
THE PERIOD FROM TUESDAY NIGHT INTO WEDNESDAY NIGHT STILL APPEARS TO
BE QUITE ACTIVE. STILL THINKING THAT DISCRETE STORMS/CLUSTERS THAT
DEVELOP ALONG THE PLAINS COLD FRONT AND DRYLINE IN THE AFTERNOON
WILL QUICKLY GROW UPSCALE INTO A LINE/QLCS CONSIDERING THE DEEP
LAYER SHEAR VECTORS WITH ONLY A SMALL ANGLE FROM THE
BOUNDARY/FORCING. THE UPPER TROF WILL BE ONLY SLOWLY PROGRESSIVE
AS IT BECOMES MORE ELONGATED WHEN THE INITIAL UPPER LOW LIFTS NNE
AND ANOTHER SHORTWAVE DIGGS THRU THE BASE. THE NET EFFECT IS
BACKING OF THE UPPER LEVEL FLOW AND POTENTIAL SLOWING OF THE
EASTWARD MOVEMENT OF THE LINE/QLCS OVERNIGHT TUESDAY. THE NAM/CMC
GEM HAVE SLOWED CONSIDERABLY...HOWEVER THE ECMWF AND GFS CONTINUE
TO HAVE A GOOD DEAL OF QPF INTO EASTERN MO. WITH THIS IN MIND I
HAVENT MADE ANY RADICAL CHANGES. AMPLE INSTABILITY AND STRONG DEEP
LAYER SHEAR CONTINUE TO SUPPORT A SEVERE THREAT WITH ANY
THUNDERSTORMS. THE OVERALL EVOLUTION OF STORMS ON WED/WED NIGHT IS
A BIT UNCERTAIN DUE TO UNKNOWNS OF THE OVERNIGHT STORMS ON TUESDAY
NIGHT. THE COLD FRONT WILL BE SLOWLY MOVING ACROSS THE AREA AND
DEEP LAYER FORCING BOTH AHEAD AND BEHIND THE FRONT WILL BE
INCREASING THROUGH THE DAY AS HEIGHT FALLS SPREAD ACROSS THE AREA.
THIS SHOULD TRANSLATE TO WIDESPREAD COVERAGE OF STORMS BOTH ALONG
THE FRONT AND SHOWERS AND STORMS IN THE COOLER AIR. DEEP LAYER
SHEAR WILL BE STRONG AND THE DEGREE OF SEVERE WEATHER IN THE WARM
SECTOR WILL BE LARGELY DICTICATED BY THE AMOUNT OF INSTABILITY
WHICH WILL BE PRESENT...WHICH IS COMPLICATED BY CLOUD COVER AND
ONGOING STORMS IN THE MORNING. WE WILL ALSO HAVE TO KEEP AN EYE ON
ANY HEAVY RAINFALL POTENTIAL GIVEN THE SLOW MOVEMENT AND HIGH
MOISTURE CONTENT OF THE ATMOSPHERE.
MUCH COOLER CONDITIONS ARE EXPECTED ON THURSDAY WITH EXTENSIVE
CLOUDINESS WITHIN THE CYCLONIC FLOW IN THE WAKE OF THE FRONT. THE
PRESENCE OF A TRAILING VORT MAX AND COLD AIR ALOFT ALSO SUGGESTS A
CHANCE OF INSTABILITY SHOWERS. THE BELOW AVERAGE TEMPERATURES WILL
PERSIST FRIDAY WITH A SLIGHT MODERATION ON SATURDAY. TEMPERATURES
SHOULD WARM TO ABOVE AVERAGE SUNDAY INTO MONDAY AS THE FLOW ALOFT
TRANSITIONS TO QUASI-ZONAL AND SOUTHERLY LOW LEVEL FLOW GETS
UNDERWAY.
GLASS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1218 PM CDT MON APR 8 2013
OUTFLOW BOUNDARY CURRENTLY LOCATED NEAR KUIN WILL REMAIN SOMEWHAT
STATIONARY BEFORE LIFTING NWD LATER THIS AFTERNOON OR EVENING.
KUIN AND KCOU HAVE BEST CHANCES FOR SEEING TSRA THIS AFTERNOON
AND EVENING...BUT CONFIDENCE IS STILL TOO LOW TO PIN DOWN A TIME.
WITH THE BOUNDARY IN THE AREA...CAN NOT RULE OUT THE POSSIBILITY
OF SEEING HIGH END MVFR CIGS AT KUIN PERIODICALLY THIS AFTERNOON.
OTHERWISE...WINDS WILL BACK TO SLY THIS AFTERNOON AND REMAIN SLY
THRU TUES. WINDS SHUD PICK UP TUES WITH GUSTS IN THE 20 KT RANGE.
MUCH BETTER CHANCES EXIST FOR HIGH END MVFR OR LOW VFR CIGS TUES.
LOOKING AT LATEST SAT IMAGE...APPEARS OZARK MNTS ARE BLOCKING
MOISTURE RETURN. EXPECT THAT THIS LOW LVL MOISTURE WILL MOVE NWD
BY TUES...BUT STILL UNCERTAIN HOW FAR N IT WILL BE. WILL LEAVE AS
A SCT DECK FOR NOW.
SPECIFICS FOR KSTL...EXPECT ANY PRECIP TO BE N OF THE TERMINAL
THIS AFTERNOON/EVENING...BUT CAN NOT COMPLETELY RULE OUT THE
POSSIBILITY. WINDS SHUD BACK TO SLY LATE THIS AFTERNOON AND REMAIN
SLY THRU TUES AND INCREASE WITH GUSTS TO AROUND 20 KTS TUES
MORNING.
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1234 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1146 AM CDT MON APR 8 2013
QUICK UPDATE TO TWEAK TEMPS FOR TODAY AND WILL BE UPDATING POPS SOON.
MAIN QUESTION REMAINS WHERE AND WHEN CONVECTION WILL INITIATE. IF
PRECIP DOES OCCUR...BELIEVE THERE WILL BE TWO AREAS. ONE ACROSS
NRN PORTIONS OF THE CWA ALONG AN OUTFLOW BNDY WITH CONVECTION FROM
LAST NIGHT AND THE OTHER ACROSS SRN PORTIONS OF THE CWA. BOTH OF
THESE AREAS HAVE ALREADY HAVE A GOOD CU FIELD.
WITH THE DEEPER CU IN PLACE...SFC BNDY AND STRONGER
CONVERGENCE...BELIEVE THAT THE BOUNDARY ACROSS THE NRN CWA WILL
SEE THE BEST CHANCES FOR PRECIP. WILL BE UPDATING TO INCREASE POPS
ACROSS THIS AREA...BUT WILL LEAVE IN THE CHANCE RANGE FOR NOW.
TILLY
&&
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1218 PM CDT MON APR 8 2013
OUTFLOW BOUNDARY CURRENTLY LOCATED NEAR KUIN WILL REMAIN SOMEWHAT
STATIONARY BEFORE LIFTING NWD LATER THIS AFTERNOON OR EVENING.
KUIN AND KCOU HAVE BEST CHANCES FOR SEEING TSRA THIS AFTERNOON
AND EVENING...BUT CONFIDENCE IS STILL TOO LOW TO PIN DOWN A TIME.
WITH THE BOUNDARY IN THE AREA...CAN NOT RULE OUT THE POSSIBILITY
OF SEEING HIGH END MVFR CIGS AT KUIN PERIODICALLY THIS AFTERNOON.
OTHERWISE...WINDS WILL BACK TO SLY THIS AFTERNOON AND REMAIN SLY
THRU TUES. WINDS SHUD PICK UP TUES WITH GUSTS IN THE 20 KT RANGE.
MUCH BETTER CHANCES EXIST FOR HIGH END MVFR OR LOW VFR CIGS TUES.
LOOKING AT LATEST SAT IMAGE...APPEARS OZARK MNTS ARE BLOCKING
MOISTURE RETURN. EXPECT THAT THIS LOW LVL MOISTURE WILL MOVE NWD
BY TUES...BUT STILL UNCERTAIN HOW FAR N IT WILL BE. WILL LEAVE AS
A SCT DECK FOR NOW.
SPECIFICS FOR KSTL...EXPECT ANY PRECIP TO BE N OF THE TERMINAL
THIS AFTERNOON/EVENING...BUT CAN NOT COMPLETELY RULE OUT THE
POSSIBILITY. WINDS SHUD BACK TO SLY LATE THIS AFTERNOON AND REMAIN
SLY THRU TUES AND INCREASE WITH GUSTS TO AROUND 20 KTS TUES
MORNING.
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1158 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1146 AM CDT MON APR 8 2013
QUICK UPDATE TO TWEAK TEMPS FOR TODAY AND WILL BE UPDATING POPS SOON.
MAIN QUESTION REMAINS WHERE AND WHEN CONVECTION WILL INITIATE. IF
PRECIP DOES OCCUR...BELIEVE THERE WILL BE TWO AREAS. ONE ACROSS
NRN PORTIONS OF THE CWA ALONG AN OUTFLOW BNDY WITH CONVECTION FROM
LAST NIGHT AND THE OTHER ACROSS SRN PORTIONS OF THE CWA. BOTH OF
THESE AREAS HAVE ALREADY HAVE A GOOD CU FIELD.
WITH THE DEEPER CU IN PLACE...SFC BNDY AND STRONGER
CONVERGENCE...BELIEVE THAT THE BOUNDARY ACROSS THE NRN CWA WILL
SEE THE BEST CHANCES FOR PRECIP. WILL BE UPDATING TO INCREASE POPS
ACROSS THIS AREA...BUT WILL LEAVE IN THE CHANCE RANGE FOR NOW.
TILLY
&&
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 601 AM CDT MON APR 8 2013
WARM FRONT HAS MOVED N OF THE TAF SITES LEADING TO S-SWLY SFC
WINDS TODAY AND S-SELY SFC WINDS TGT. ALTHOUGH THERE SHOULD BE SCT-
BKN VFR...LOW LEVEL CLOUDS TODAY AND TGT IT APPEARS THAT THE
MODELS ARE OVERDOING THE LOW LEVEL...BOUNDARY LAYER RH AND ARE
TOO LOW WITH THE CLOUD CEILING FORECAST IN THE MOS GUIDANCE. FOR
NOW WILLL KEEP IT VFR THROUGH THE PERIOD IN THE TAF FORECASTS.
THERE IS ALSO THE POTENTIAL FOR WIDELY SCATTERED SHOWERS OR STORMS
THIS AFTN ACROSS MUCH OF THE AREA...AND SCATTERED SHOWERS AND
STORMS ACROSS NERN MO AND W CNTRL IL TGT. WITH PLENTY OF UNCERTAINTY
WITH TIMING AND LOCATION OF THE CONVECTION WILL LEAVE THE TAFS DRY
FOR NOW.
SPECIFICS FOR KSTL...WITH PLENTY OF LOW LEVEL MOISTURE AND
INSTABILITY THERE WILL BE SCT-BKN DIURNAL CUMULUS CLOUDS THIS
AFTN. MOST OF THIS SHOULD BE VFR. WILL LIKELY HAVE AT LEAST SCT
LOW LEVEL CLOUDS TGT INTO TUE MRNG. THERE MAY BE WIDELY SCATTERED
TO SCATTERED SHOWERS AND STORMS THIS AFTN AND TGT...BUT WILL
LEAVE THE STL TAF DRY FOR NOW WITH NO WELL DEFINED SFC BOUNDARY OR
FORCING MECHANISM TO FOCUS AND INITIATE CONVECTION. S-SWLY SFC
WIND SHOULD CONTINUE TODAY...THEN BECOME MORE S-SELY THIS EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
647 AM CDT MON APR 8 2013
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 601 AM CDT MON APR 8 2013
WARM FRONT HAS MOVED N OF THE TAF SITES LEADING TO S-SWLY SFC
WINDS TODAY AND S-SELY SFC WINDS TGT. ALTHOUGH THERE SHOULD BE SCT-
BKN VFR...LOW LEVEL CLOUDS TODAY AND TGT IT APPEARS THAT THE
MODELS ARE OVERDOING THE LOW LEVEL...BOUNDARY LAYER RH AND ARE
TOO LOW WITH THE CLOUD CEILING FORECAST IN THE MOS GUIDANCE. FOR
NOW WILLL KEEP IT VFR THROUGH THE PERIOD IN THE TAF FORECASTS.
THERE IS ALSO THE POTENTIAL FOR WIDELY SCATTERED SHOWERS OR STORMS
THIS AFTN ACROSS MUCH OF THE AREA...AND SCATTERED SHOWERS AND
STORMS ACROSS NERN MO AND W CNTRL IL TGT. WITH PLENTY OF UNCERTAINTY
WITH TIMING AND LOCATION OF THE CONVECTION WILL LEAVE THE TAFS DRY
FOR NOW.
SPECIFICS FOR KSTL...WITH PLENTY OF LOW LEVEL MOISTURE AND
INSTABILITY THERE WILL BE SCT-BKN DIURNAL CUMULUS CLOUDS THIS
AFTN. MOST OF THIS SHOULD BE VFR. WILL LIKELY HAVE AT LEAST SCT
LOW LEVEL CLOUDS TGT INTO TUE MRNG. THERE MAY BE WIDELY SCATTERED
TO SCATTERED SHOWERS AND STORMS THIS AFTN AND TGT...BUT WILL
LEAVE THE STL TAF DRY FOR NOW WITH NO WELL DEFINED SFC BOUNDARY OR
FORCING MECHANISM TO FOCUS AND INITIATE CONVECTION. S-SWLY SFC
WIND SHOULD CONTINUE TODAY...THEN BECOME MORE S-SELY THIS EVNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
300 AM CDT MON APR 8 2013
.SHORT TERM...(THROUGH TUESDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHEAST MISSOURI AND WEST
CENTRAL ILLINOIS IS MOVING QUICKLY NORTHEAST AHEAD OF A MID LEVEL
SHORTWAVE TROUGH. THERE IS A NARROW BAND OF THUNDERSTORMS THAT
EXTENDS BACK SOUTHWESTWARD INTO CENTRAL MISSOURI ON THE NOSE OF A
50KT LOW LEVEL JET. AMOUNT OF INSTABILITY LESSENS OVER EASTERN
MISSOURI AND SOUTHWEST ILLINOIS AND LATEST RAP RUNS SHOW THAT STRONG
MOISTURE CONVERGENCE WILL MOVE QUICKLY NORTHEAST OUT OF THE CWA BY
12Z. CURRENT THINKING IS THAT THIS LINE WILL SHOW SOME WEAKENING AS
IT EXITS THE AREA EARLY THIS MORNING.
MODEL CONSENSUS STILL SHOWS THAT THE EAST-WEST ORIENTED FRONT
CURRENTLY OVER THE NORTHERN CWA WILL MOVE NORTH INTO SOUTHERN IOWA
LATER THIS MORNING AS HEIGHTS BEGIN TO INCREASE IN RESPONSE TO
DEEPENING SOUTHWESTERN CONUS UPPER LOW. THIS FRONT IS EXPECTED TO
BECOME QUASI-STATIONARY INTO TUESDAY NIGHT LEAVING THE CWA IN THE
WARM SECTOR THROUGH TOMORROW. IT STILL APPEARS THAT THE ATMOSPHERE
WILL BECOME INCREASINGLY UNSTABLE DURING THIS PERIOD AS LOW LEVEL
MOISTURE INCREASES UNDER STEEPENING LAPSE RATES. MODEL FORECAST
SOUNDINGS ARE SHOWING A WARM LAYER BETWEEN 800-600MB WHICH WILL KEEP
THE WARM SECTOR CAPPED...SO THINK THUNDERSTORM COVERAGE WILL BE
ISOLATED/SCATTERED. THE EXCEPTION WILL BE OVER NORTHERN MISSOURI/
WEST CENTRAL ILLINOIS LATE TONIGHT/EARLY TUESDAY WHEN THE LOW LEVEL
JET INTERACTS WITH FRONT.
TEMPERATURES CLIMBED ABOVE GUIDANCE ON SUNDAY AND DO NOT SEE MUCH
REASON THEY WILL NOT DO IT AGAIN TODAY AND TUESDAY IN THE WARM
SECTOR...PARTICULARLY IF THE CLOUDS BREAK UP MORE THAT FORECAST.
BRITT
.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM CDT MON APR 8 2013
(TUESDAY NIGHT THROUGH THURSDAY)
MAIN CONCERN CONTINUES TO BE SEVERE THUNDERSTORM POTENTIAL DURING
THIS PERIOD. NOT MUCH CHANGE FROM PREVIOUS THINKING THAT STORMS
THAT DO DEVELOP ALONG THE COLD FRONT OVER OKLAHOMA/KANSAS ON
TUESDAY AFTERNOON WILL MERGE INTO A LINE AND MOVE INTO THE CWA
LATE TUESDAY NIGHT. AT 12Z WEDNESDAY...THE NAM/ECMWF BOTH DEPICT
THAT THE SURFACE LOW WILL BE OVER NORTH CENTRAL MISSOURI WITH THE
ATTENDANT COLD FRONT EXTENDING BACK INTO EASTERN OKLAHOMA. THE GFS
SHOWS THE LOW TO THE SOUTHEAST...BUT EACH OF THE MODELS DO NOT
HAVE THE FRONT CLEARING THE EASTERN CWA BY 00Z. IT IS STILL
UNCLEAR WHETHER THE FIRST ROUND OF STORMS WILL STABILIZE THE
ATMOSPHERE SO MUCH THAT IT WILL HINDER REDEVELOPMENT AHEAD OF THE
COLD FRONT ON WEDNESDAY. IF NOT...THE ATMOSPHERE WILL BE
MODERATELY UNSTABLE WITH IMPRESSIVE FORCING AND DEEP LAYER SHEAR.
THERE WILL ALSO BE THE POTENTIAL FOR LOCALLY HEAVY RAINFALL AS
DEEP LAYER FLOW WILL BE NEARLY PARALLEL TO UPPER FLOW.
RAIN WILL MOVE OUT OF THE AREA SLOWLY ON WEDNESDAY NIGHT INTO
THURSDAY AS THE FRONT PUSHES EAST OF THE AREA. STILL...LOW LEVEL
FRONT WILL BE CYCLONIC WITH THE UPPER LOW PASSING JUST NORTH OF THE
AREA FAVORING CLOUDS AND SCATTERED SHOWERS ON THURSDAY. THERE
WILL BE A STARK DROP IN TEMPERATURES BEHIND THE FRONT AS 850MB
TEMPERATURES FALLS TO AROUND -4C ON THURSDAY NIGHT.
(FRIDAY THROUGH SUNDAY)
NEXT WEEKEND STILL LOOKS DRY AS UPPER FLOW GOES FROM NORTHWESTERLY
TO ZONAL IN WAKE OF THE UPPER LOW. THERE WILL BE A GRADUAL WARMUP
AS ECMWF/GFS HAVE 850MB TEMPS CLIMBING ABOVE 10C AS THE LOW LEVEL
FLOW TURNS BACK SOUTHWESTERLY.
BRITT
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM CDT SUN APR 7 2013
FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH FORECAST AREA THIS
EVENING WITH INITIAL ACTIVITY DIMINISHING. MAIN FOCUS SHIFTS BACK
TO THE WEST AND NORTHWEST OF FORECAST AREA...WITH STORMS FIRING ON
NOSE OF LOW LEVEL JET. WILL SEE THIS ACTIVITY SLIDE NORTHEAST...
WITH KCOU REMAINING ON EASTERN FRINGES OF PCPN. WHILE KUIN...
SHOULD SEE PLENTY OF PCPN OVERNIGHT AS LOW LEVEL JET BEGINS TO
SHIFT TO A MORE SOUTHWESTERLY DIRECTION. VFR CIGS TO LOWER TO MVFR
WITH PCPN...BEFORE LIFTING AND SCATTERING OUT BY MID MORNING AS
RAIN COMES TO AN END. AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS
OVER THE NEXT SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF
TO VCSH MENTION BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR
THROUGH THE PERIOD. WINDS TO REMAIN FROM THE SOUTHEAST TO SOUTH
THROUGH THE FORECAST PERIOD.
SPECIFICS FOR KSTL...FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH
FORECAST AREA THIS EVENING WITH INITIAL ACTIVITY DIMINISHING.
MAIN FOCUS SHIFTS BACK TO THE WEST AND NORTHWEST OF FORECAST
AREA...WITH STORMS FIRING ON NOSE OF LOW LEVEL JET. WILL SEE THIS
ACTIVITY SLIDE NORTHEAST...AND REMAIN WELL NORTHWEST OF METRO AREA.
AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS OVER THE NEXT
SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF TO VCSH MENTION
BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR THROUGH THE PERIOD.
WINDS TO REMAIN FROM THE SOUTH THROUGH 13Z...BEFORE VEERING TO THE
SOUTHWEST THROUGH MIDDAY...THEN BACK TO THE SOUTH ONCE AGAIN.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1140 PM CDT SUN APR 7 2013
.UPDATE...
ISSUED AT 904 PM CDT SUN APR 7 2013
SHOWER AND THUNDERSTORM ACTIVITY HAS BEEN ONGOING IN A NORTHWARD
LIFTING FRONTAL ZONE DRAPED ACROSS THE MIDSECTION OF THE CWA THIS
EVENING. LATEST RUC DATA ALONG WITH THE 4KM NSSL NMM WRF INDICATE
THE POTENTIAL FOR THE STORMS TO CONTINUE TO PERCOLATE IN THE
AFOREMENTIONED FRONTAL ZONE...WITH LOCALIZED MUCAPE VALUES AOA
200-400 J/KG. STORMS HAVE THUS FAR REMAINED SUB-SEVERE...HOWEVER
HAIL UP TO NICKEL SIZE HAS BEEN REPORTED WITH SOME OF THE STRONGER
STORMS OVER THE STL METRO EAST.
HAVE ADJUSTED TIMING OF PRECIPITATION THIS EVENING...ESPECIALLY
OVER THE WESTERN HALF OF THE CWA...WITH TWO MAIN AREAS OF CONCERN.
THE FIRST IS WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY THAT HAS
OVERSPREAD NW MO AND EASTERN KS THIS EVENING...EXPECTED TO MOVE
INTO CENTRAL AND NE MO THROUGH THE EARLY OVERNIGHT HOURS ON THE
NOSE OF AN INTENSIFYING LLJ. THE SECOND AREA OF CONCERN IS A
POTENT STORM MOVING THROUGH SOUTH CENTRAL MO WHICH HAS MAINTAINED
INTENSITY AS IT MARCHES EASTWARD. MODELS FORECAST THE STORM TO
WEAKEN PRIOR TO IMPACTING OUR SOUTHERN COUNTIES...THOUGH THE FACT
THAT IT HAS CONSISTENTLY PRODUCED GOLFBALL SIZED HAIL AND DOES NOT
APPEAR TO BE DIMINISHING IN STRENGTH HAS PIQUED OUR INTEREST A
BIT. MAY HAVE TO FURTHER ADJUST POPS OVER SOUTHERN COUNTIES IF
THIS STORM MAINTAINS ITS INTENSITY AND CURRENT TRACK. WILL
CONTINUE TO MONITOR THIS FEATURE CLOSELY.
OTHERWISE...THE FORECAST HAS REMAINED ON TRACK THIS
EVENING...WITH ONLY A FEW CHANGES TO TEMPERATURE AND DEWPOINT
TRENDS TO ACCOUNT FOR LOCATIONS WITH RAIN COOLED AIR DUE TO STORM
ACTIVITY TONIGHT.
JP
&&
.SHORT TERM...(TONIGHT THROUGH MONDAY)
ISSUED AT 315 PM CDT SUN APR 7 2013
WHILE THE PRECIPITATION CHANCES ARE EXPECTED TO RAMP UP CONSIDERABLY
TONIGHT...THE EXACT DETAILS ARE STILL A TAD UNCLEAR. THIS IS IN
PART DUE TO DIFFERENCES AMONGST THE DETERMINISTIC MODELS AND
CONVECTION ALLOWING MODELS WITH RESPECT TO THE CONVECTIVE
EVOLUTION AND TIMING. THE OVERALL SCENARIO REMAINS UNCHANGED. A
QUASI-STATIONARY BOUNDARY NOW STRETCHES FROM NW MO THROUGH CENTRAL
MO WHERE IT THEN TAILS EASTWARD THRU THE ST LOUIS AREA INTO SE
ILLINOIS. MOISTURE ADVECTION TODAY AND HEATING HAS RESULTED IN A
WEAKLY UNSTABLE AIR MASS TO THE SOUTH OF THE BOUNDARY AND A GOOD
DEAL OF AGITATED CU IS NOW PRESENT. EVEN A FEW SPOTTY SHOWERS HAVE
DEVELOPED SSE OF ST LOUIS. THIS BOUNDARY IS FORECAST TO GRADUALLY
RETREAT NORTHWARD TONIGHT WHILE THE LOW AMPLITUDE SHORT WAVE NOW
OVER CENTRAL KS MOVES EASTWARD THRU THE AREA IN CONJUNCTION WITH
AN INTENSIFYING AND VEERING SWLY LLJ. ALL THE STRONG FORCING VIA
THE SHORTWAVE AND LLJ ARE FOCUSED ALONG AND NORTH OF I-70 WITHIN
THE COOL SECTOR NORTH OF THE RETREATING BOUNDARY. MY BEST GUESS IS
THAT THERE COULD BE SEVERAL WAVES OF ORGANIZED CONVECTION. THE
GROWING CONVECTION PRESENTLY IN SE KS MAY PUSH ENE INTO CENTRAL MO
THIS EVENING WHILE ADDITIONAL ISOLATED-SCATTERED CONVECTION COULD
ATTEMPT TO DEVELOP ALONG AND JUST SOUTH OF THE FRONT ZONE. THEN LATER
THIS EVENING AND TONIGHT ONE OR MORE CONVECTIVE CLUSTERS SHOULD
DEVELOP ACROSS NE KS AND NW MO AND MOVE EASTWARD IN CONJUNCTION
WITH THE VEERING LLJ AND MIGRATING SHORTWAVE TROF. WITH PLENTLY OF
DEEP LAYER SHEAR PRESENT...DEPENDING ON THE CAPE EVOLUTION...A FEW
OF THESE STORMS ACROSS CENTRAL MO COULD BE SEVERE.
I THINK BY DAYBREAK MONDAY...MOST OF THE OVERNIGHT CONVECTION
SHOULD BE NE OF THE CWA AS THE SHORTWAVE IS WELL TO THE EAST AND
THE LLJ IS STRONGLY VEERED TO THE WEST SOUTHWEST...HOWEVER I CANT
RULE OUT SOME SCATTERED TRAILING STORMS ALONG THE LLJ AXIS AND ANY
RESIDUAL BOUNDARIES. EVEN IF THIS IS PRESENT...I WOULD THINK IT
SHOULD HAVE EXITED THE AREA BY MID-LATE MORNING. THEREAFTER THE
EML BUILDS IN STRONGLY THROUGH THE AFTERNOON AND RESULTS IN
SUBSTANTIAL CAPPING OF THE WARM SECTOR...WITH THE FRONT LIFTING
INTO IOWA. THUS AFTERNOON THUNDERSTORM CHANCES LOOK MORE ISOLATED
BARING ANY LINGERING BOUNDARIES.
GLASS
.LONG TERM...(MONDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 244 PM CDT SUN APR 7 2013
THE LAST FEW DAYS THE ECMWF MODEL HAS BEEN AN OUTLIER WITH A MORE
SOUTHWARD EAST-WEST ORIENTED BOUNDARY POSITION ACROSS NORTHERN
MISSOURI FROM MONDAY THROUGH TUESDAY NIGHT. ON THE LAST 2 RUNS
HOWEVER THE ECMWF HAS JOINED THE REST OF THE MODELS WITH A MORE
NORTHWARD BOUNDARY POSITION ACROSS SOUTHERN IOWA OR THE MO/IA
BORDER. THIS WOULD SUGGEST LESSER PRECIPITATION CHANCES ACROSS
NORTHERN MISSOURI DUE TO THE LACK OF A FOCUSING BOUNDARY...AND AS
THE WARM SECTOR IS EXPECTED TO BE CHARACTERIZED BY A DECENT CAP
FOR SURFACE BASED STORMS UNTIL LATE TUESDAY NIGHT. THE MOST ACTIVE
PERIOD IS STILL EXPECTED TO BE THE LATE TUESDAY NIGHT INTO
WEDNESDAY TIME FRAME WHEN THE DEEP LARGE SCALE TROF AND ATTENDANT
COLD FRONT PROGRESSES EASTWARD INTO THE NATIONS MIDSECTION. I
STILL BELIEVE THE SCENARIO I LAYED OUT YESTERDAY IS QUITE
LIKELY... THAT THE ORGANIZED SEVERE CONVECTION ACROSS THE PLAINS
ON TUESDAY AFTERNOON WILL GROW UPSCALE INTO A LINE/QLCS AND SHIFT
EASTWARD INTO THE AREA OVERNIGHT TUESDAY INTO WEDNESDAY MORNING.
IT NOW APPEARS THAT ADDITIONAL STORMS COULD DEVELOP THROUGHOUT THE
DAY ON WEDNESDAY AND WED EVENING AHEAD OF THE COLD FRONT MOVING
ACROSS THE AREA...BUT THIS WILL BE LARGELY DEPENDENT ON STABILIZING
EFFECTS OF ANY PREVIOUS CONVECTION. STRONG DEEP LAYER SHEAR AND
AMPLE INSTABILITY SUPPORTS A SEVERE WEATHER THREAT PER THE SPC
OUTLOOKS.
IN THE WAKE OF THE MIDWEEK SYSTEM THERE WILL BE A GOOD COOL DOWN
THUR-FRIDAY TO BELOW AVERAGE TEMPS WITH BROAD CYCLONIC FLOW ALOFT
AND HIGH PRESSURE DOMINATING IN THE WAKE OF THE WEAKENING
PROGRESSIVE LONGWAVE TROF. THE FLOW ALOFT LOOKS TO TRANSITION TO
QUASI-ZONAL BY WEEKEND WITH THE SURFACE HIGH RETREATING...LEADING
TO MODERATING TEMPERATURES.
GLASS
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1140 PM CDT SUN APR 7 2013
FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH FORECAST AREA THIS
EVENING WITH INITIAL ACTIVITY DIMINISHING. MAIN FOCUS SHIFTS BACK
TO THE WEST AND NORTHWEST OF FORECAST AREA...WITH STORMS FIRING ON
NOSE OF LOW LEVEL JET. WILL SEE THIS ACTIVITY SLIDE NORTHEAST...
WITH KCOU REMAINING ON EASTERN FRINGES OF PCPN. WHILE KUIN...
SHOULD SEE PLENTY OF PCPN OVERNIGHT AS LOW LEVEL JET BEGINS TO
SHIFT TO A MORE SOUTHWESTERLY DIRECTION. VFR CIGS TO LOWER TO MVFR
WITH PCPN...BEFORE LIFTING AND SCATTERING OUT BY MID MORNING AS
RAIN COMES TO AN END. AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS
OVER THE NEXT SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF
TO VCSH MENTION BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR
THROUGH THE PERIOD. WINDS TO REMAIN FROM THE SOUTHEAST TO SOUTH
THROUGH THE FORECAST PERIOD.
SPECIFICS FOR KSTL...FRONTAL BOUNDARY HAS LIFTED NORTHWARD THROUGH
FORECAST AREA THIS EVENING WITH INITIAL ACTIVITY DIMINISHING.
MAIN FOCUS SHIFTS BACK TO THE WEST AND NORTHWEST OF FORECAST
AREA...WITH STORMS FIRING ON NOSE OF LOW LEVEL JET. WILL SEE THIS
ACTIVITY SLIDE NORTHEAST...AND REMAIN WELL NORTHWEST OF METRO AREA.
AS FOR METRO AREA...WILL SEE SOME LIGHT SHOWERS OVER THE NEXT
SEVERAL HOURS...WITH JUST VCTS MENTION...TAPER OFF TO VCSH MENTION
BETWEEN 09Z AND 13Z...WITH CIGS REMAINING VFR THROUGH THE PERIOD.
WINDS TO REMAIN FROM THE SOUTH THROUGH 13Z...BEFORE VEERING TO THE
SOUTHWEST THROUGH MIDDAY...THEN BACK TO THE SOUTH ONCE AGAIN.
BYRD
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS BILLINGS MT
927 PM MDT TUE APR 9 2013
.UPDATE...
OVERALL FORECAST IN GOOD SHAPE...BUT DID MAKE SOME MINOR TWEAKS.
CONSIDERABLE DIVERGENCE FROM UPPER LOW OVER COLORADO IS STILL
AFFECTING EXTREME SE MONTANA. RAISED POPS TO CATEGORICAL IN SE
CARTER COUNTY...BUT DO NOT EXPECT MUCH MORE THAN A HALF INCH OR SO
OF ADDITIONAL ACCUMULATION. LOWERED POPS IN SOUTHERN BIG HORN AND
SHERIDAN AREAS.
OVERNIGHT LOWS WILL BE DIFFICULT DUE TO LINGERING CLOUD COVER IN
EAST...LOCAL SNOW DEPTHS VERSUS SNOW WHICH MELTED TODAY. SHORT
TERM MODELS BRING SOME VERY DRY AIR INTO THE WESTERN ZONES LATER
TONIGHT. THIS IS NOTED ON THE WATER VAPOR LOOP CURRENTLY FROM
BOZEMAN TO LEWISTOWN. NOT SURE THIS WILL MIX DOWN INTO BOUNDARY
LAYER THAT WELL TONIGHT...BUT DECIDED TO LOWER DEWPOINTS AND TEMPS
A BIT AS SKIES WILL AT LEAST BECOME QUITE CLEAR OVERNIGHT IN THE
WESTERN HALF OF THE FORECAST AREA. BT
&&
.SHORT TERM...VALID FOR TONIGHT...
WE DECIDED TO CANCEL THE REST OF THE WINTER STORM WARNING WITH
THE AFTERNOON FORECAST. THE MAIN ATTENTION-GRABBER TONIGHT WILL BE
THE COLD TEMPERATURES /WITH RECORD LOWS POSSIBLE IN SOME
LOCATIONS/.
AS OF 21 UTC...MOISTURE CHANNEL IMAGERY SUGGESTS THE CLOSED LOW
AT 500-HPA IS CENTERED ACROSS COLORADO...AND EVEN HIGH-LEVEL
MOISTURE SAMPLING SHOWS A WEAKENING DEFORMATION ZONE OVER SOUTHERN
MONTANA. THAT REFLECTS THE NOW-WEAKENING FORCING THAT GENERATED
SNOW DURING THE PAST 24 HOURS...AND CONFIRMS THE MODEL EXPECTATION
FOR 500-300 HPA Q-VECTOR CONVERGENCE TO BE ON THE DOWNSWING IN OUR
AREA. THERE IS ANOTHER BATCH OF MOISTURE WITH COOLING CLOUD TOPS
HEADED TO THE NORTH ACROSS WYOMING AS OF MID AFTERNOON AS
WELL...AND THAT IS THE FEATURE OF INTEREST HEADING INTO TONIGHT.
IT LOOKS LIKE THE 12 UTC NAM HANDLES THIS SCENARIO WELL...AND IT
DOES SHOW RENEWED SNOWFALL IN EXTREME SOUTHEASTERN MT /NAMELY FAR
SOUTHERN CARTER COUNTY NEAR ALZADA AND ALBION/ OVERNIGHT. THE 20
UTC RAP HAS A SIMILAR TYPE OF SOLUTION...BUT EXTENDS ITS MOISTURE
ANOTHER 50 TO 75 MILES FURTHER WEST AFTER 06 UTC. THAT DOES NOT
FIT WITH THE REST OF THE GUIDANCE FROM 12 UTC...SO RIGHT NOW IT
LOOKS LIKE A BIT OF AN OUTLIER.
SO...WE EXTRAPOLATED OBSERVATIONALL TRENDS AND LEANED ON THE 12
UTC NAM TO BUILD THE OVERNIGHT FORECAST. THAT GENERALLY MEANT
REDUCING POPS AND SNOW AMOUNTS FROM SHERIDAN TO EKALAKA...WITH
POPS LEFT IN THE LIKELY RANGE ONLY FROM ABOUT BIDDLE TO ALBION AND
ALZADA AFTER 06 UTC. AN INCH OR TWO OF ADDITIONAL SNOWFALL IS
ADVERTISED ACROSS THAT AREA AS WELL...BUT WEB CAMERA IMAGES ALONG
HIGHWAY 212 DURING THE AFTERNOON SUGGEST THAT CONDITIONS HAVE
GREATLY IMPROVED. THERE WAS SIMILAR EVIDENCE ACROSS THE REST OF
THE WARNED AREA...AND ONLY FLURRIES ARE EVEN BEING REPORTED AT
SHERIDAN NOW. THUS...THERE ARE NO LONGER ENOUGH CURRENT OR
EXPECTED IMPACTS TO KEEP WARNINGS UP.
OTHERWISE...THE TIMING OF CLEARING WILL BE THE KEY TO HOW FAR LOWS
FALL. A FRESH SNOW PACK AND SURFACE RIDGING WITH LIGHT FLOW IN THE
BOUNDARY LAYER WILL MAKE FOR FAVORABLE RADIATIONAL COOLING WHERE A
CLEAR SKY DOES DEVELOP. WE USED THE 12 UTC MET /NAM-BASED/ MOS AND
MID-AFTERNOON DEWPOINTS AS A GUIDE FOR OVERNIGHT LOWS. SHERIDAN TO
BAKER IS THE CORRIDOR LEAST LIKELY TO HAVE ENOUGH REDUCTION IN THE
CLOUDS FOR EFFICIENT RADIATIONAL COOLING...BUT THAT AREA WILL ALSO
HAVE THE SHORTEST DISTANCE TO FALL TO DROP BELOW ABOUT 15 DEGREES.
WE HAVE ENOUGH CONFIDENCE IN THE FORECAST TO BELIEVE DAILY RECORDS
COULD BE TIED OR FALL AT BILLINGS...MILES CITY...AND SHERIDAN. ONE
INTERESTING THING TO NOTE IS THAT DAILY RECORD LOWS MAY BE SET FOR
BOTH APRIL 9TH AND THE 10TH IF TEMPERATURES FALL FAST ENOUGH PRIOR
TO MIDNIGHT AT BILLINGS AND MILES CITY...WHERE THE CURRENT RECORDS
FOR THE 9TH ARE 16 DEGREES /SET IN 1973/. FOR APRIL 10TH...CURRENT
RECORDS ARE AT 11 DEGREES AT BILLINGS AND 14 DEGREES AT MILES CITY
/BOTH FROM 1940/ AND 11 DEGREES AT SHERIDAN /SET IN 1933/. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...MON...TUE...
INTERESTING PERIOD OF WEATHER FOR THE REST OF THIS WEEK AND INTO
EARLY NEXT WEEK. MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT IN
MOVING OUR CURRENT WEATHER MAKER EASTWARD INTO THE HIGH PLAINS BY
WEDNESDAY AFTERNOON.
THE FIRST SYSTEM TO IMPACT THE REGION WILL ARRIVE THIS COMING
THURSDAY...AS MODELS SHOW AN AMPLE AMOUNT OF MOISTURE AVAILABLE TO
WARRANT UPPING THE POP FORECASTS ACROSS MOST OF THE CWA. SOME
LARGE SCALE FORCING WILL ALSO BE AVAILABLE TO HELP ENHANCE THE
CHANCES OF PRECIPITATION.
BY FRIDAY WE TRANSITION INTO A MORE NORTHWESTERLY FLOW AND
PARTIAL RIDGING...BEFORE A FAIRLY STRONG WESTERLY UPPER LEVEL JET
CROSSES INTO CENTRAL WYOMING...LEAVING MT ON THE COLDER
CYCLONIC SIDE. THIS WILL HELP TO KEEP TEMPERATURES BELOW AVERAGE
AS WELL AS KEEP THE POP FORECASTS ABOVE CLIMO.
NUMEROUS BURSTS OF SHORTWAVE ENERGY AT THE MID LEVELS WILL RIDE
THE JET AND BRING THE POTENTIAL FOR ANOTHER SIGNIFICANT LATE
SEASON WINTER STORM BY EARLY NEXT WEEK. HOWEVER...AT THIS
TIME...THE TRACK OF THE MID LEVEL LOW NEEDS TO BE MONITORED..AS IT
MAY NOT BE IN THE MOST FAVORABLE POSITION FOR SOUTH CENTRAL
MONTANA...AS MOST OF THE JET DYNAMICS AND Q-VECTOR CONVERGENCE ARE
WELL SOUTH INTO CENTRAL WYOMING. A SHIFT OF THIS TRACK SLIGHTLY TO
THE NORTH MAY TRIGGER THE NEED FOR HIGHER POPS. SINGER
&&
.AVIATION...
VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE NIGHT AT ALL
TAF SITES. HOWEVER...SOME LOWER CEILINGS AND SNOW SHOWERS WILL
LINGER ACROSS FAR SOUTHEAST MONTANA OVERNIGHT. VFR CONDITIONS
WILL PREVAIL ON WEDNESDAY. CHURCH
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 013/044 032/054 032/052 035/053 030/048 026/046 027/048
01/U 53/W 22/W 34/W 33/W 33/W 33/W
LVM 011/053 031/055 026/053 032/051 023/044 020/044 020/045
01/B 73/W 22/W 34/W 33/W 33/W 33/W
HDN 012/043 029/053 030/053 034/055 031/049 026/047 026/048
01/B 55/W 22/W 34/W 33/W 33/W 23/W
MLS 015/040 025/049 029/049 032/052 032/047 028/043 026/047
11/U 35/W 23/W 25/W 43/W 33/W 22/W
4BQ 011/035 016/044 027/048 030/052 031/047 027/044 026/044
21/B 25/W 23/W 23/W 43/W 33/W 34/W
BHK 014/036 020/041 026/045 026/047 030/041 025/041 024/042
11/B 14/W 23/W 14/W 43/W 33/W 22/W
SHR 009/040 024/049 027/050 029/052 027/044 024/043 024/045
21/B 44/W 33/W 23/W 43/W 45/W 34/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
351 PM MDT MON APR 8 2013
.SHORT TERM...VALID FOR TONIGHT THROUGH TUE NIGHT...
THE THREAT OF HEAVY SNOW ON THE NORTHERN EDGE OF THE FORCING WITH
A DEEP 500-HPA TROUGH LIFTING OUT OF THE FOUR CORNERS REGION INTO
THE HIGH PLAINS THE NEXT 36 HOURS IS THE MAIN FORECAST ISSUE. WE
DECIDED TO AGGRESSIVELY ADVERTISE WARNING CRITERIA SNOW BETWEEN 7
AND 13 INCHES FOR SHERIDAN OVER TO ALBION AND MOORHEAD...AND 5 TO
10 INCHES IN THE AREA JUST NORTH OF THERE EXTENDING INTO SOUTHERN
BIG HORN COUNTY. HOWEVER...WE HAVE TO ADMIT THAT MANY OF THE SAME
QUESTIONS ABOUT THIS EVENT THAT HAVE EXISTED THE LAST COUPLE DAYS
ARE STILL LINGERING...SO THERE IS CERTAINLY A HIGHER-THAN-AVERAGE
POTENTIAL FOR FORECAST ERROR TONIGHT AND TUESDAY.
FIRST OF ALL...THE MORNING BATCH OF SNOW IN SOUTHEASTERN MT WANED
DURING THE EARLY AFTERNOON AS MID-LEVEL FRONTOGENESIS WEAKENED...
AND MOVED INTO NORTH DAKOTA. WE THUS CANCELLED THE ADVISORY A FEW
HOURS EARLY FOR FORSYTH...MILES CITY...AND BAKER BECAUSE THE NEXT
BATCH OF SNOW WILL LARGELY /OR ENTIRELY/ STAY SOUTH OF THERE.
FOR TONIGHT AND TUESDAY...WE ESSENTIALLY SET ASIDE THE 12 UTC GFS
SOLUTION SINCE IT IS A FAST OUTLIER IN TAKING THE DYNAMIC 500-HPA
TROUGH EASTWARD INTO THE PLAINS. THE GFS HAS ALSO BEEN THE DRIEST
SOLUTION IN FAR SOUTHERN MT AND NORTH CENTRAL WY...THOUGH WE NEED
TO NOTE THAT ITS 12 UTC RUN WAS ACTUALLY A BIT WETTER. THE 12 UTC
NAM...ECMWF...09 UTC SREF...AND RECENT RUNS OF THE RAP AGREE WELL
THAT SNOW WILL INTENSIFY BY 06 UTC FROM SHERIDAN TO ABOUT BUFFALO
SOUTH DAKOTA AS 500-300 HPA Q-VECTOR CONVERGENCE CRANKS UP. BASED
ON A BLEND OF THOSE SOLUTIONS...QPF WILL BE BETWEEN 0.40 AND 0.75
INCHES...WITH THE 12 AND 18 UTC NAM SOLUTIONS HEAVIER WITH NEARLY
AN INCH OF LIQUID-EQUIVALENT MOISTURE IN SOME LOCATIONS. ONLY ONE
OF THE 22 NAM-WEIGHTED SREF MEMBERS CALLS FOR STORM TOTAL LIQUID-
EQUIVALENT OF LESS THAN 0.50 INCHES AT SHERIDAN...WITH A MEAN QPF
FROM THE 15 UTC SREF OF 0.80 INCHES. SNOW-TO-LIQUID RATIOS SHOULD
BE IN THE 13 TO 17 TO 1 RANGE BASED ON A BLEND OF TECHNIQUES SUCH
AS THE COBB METHOD. FORECAST SOUNDINGS SUGGEST A PRETTY FAVORABLE
DENDRITIC GROWTH ZONE...WHICH SUPPORTS THOSE HIGHER SNOW RATIOS.
POTENTIAL PROBLEMS WITH THE FORECAST INCLUDE 1/ THE POTENTIAL FOR
SUBTLE CHANGES IN THE TRACK OF THE MID- AND UPPER-LEVEL TROUGH...
AND 2/ THE RISK OF DRIER NORTHERLY LOW-LEVEL AIR WORKING INTO THE
SYSTEM AND REDUCING SNOW TOTALS. DESPITE THOSE POSSIBILITIES...WE
HAD ENOUGH CONFIDENCE TO HOIST A WINTER STORM WARNING FOR THE FAR
SOUTHERN PART OF MONTANA...SHERIDAN COUNTY...AND THE NORTHEASTERN
BIG HORN MOUNTAINS. WE BOUNDED THAT WARNING WITH A WINTER WEATHER
ADVISORY IN SOUTHERN BIG HORN COUNTY...RECOGNIZING THAT ANY SMALL
SHIFTS IN THE NORTHERN EDGE OF THE SNOW FIELD /DETERMINED IN PART
BY THE ADVANCEMENT OR LACK THEREOF OF DRY NORTHERLY FLOW/ WILL BE
THE DRIVING FORCE IN WHERE THE ACTUAL GRADIENT IN HEAVY SNOW ENDS
UP BEING. FINALLY...WE ALSO CAUTIOUSLY ISSUED AN ADVISORY FOR THE
BEARTOOTH AND RED LODGE FOOTHILLS THROUGH 18 UTC TUESDAY BASED ON
A SUBTLE SIGNAL IN EVEN THE COARSER-SCALE GUIDANCE FOR ENOUGH QPF
TO SUPPORT 3 OR MORE INCHES OF UPSLOPE-DRIVEN SNOW THERE.
WE EXPECT SNOWFALL TO WIND DOWN TUESDAY AFTERNOON OR EVENING WHEN
DYNAMICS WANE AND SURFACE RIDGING APPROACHES. LOW TEMPERATURES ON
TUESDAY NIGHT COULD BE EVEN COLDER THAN ADVERTISED IF SUBSTANTIAL
CLEARING OCCURS AND EXPECTED SNOWFALL BECOMES REALITY. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...MON...
SYSTEM CURRENTLY IMPACTING REGION WILL EJECT INTO THE MIDWEST AND
MAKE WAY FOR THE RETURN OF NORTHWESTERLY FLOW BY THE END OF THE
WORK WEEK. A FAIRLY STRONG UPPER LEVEL JET WILL SUBSEQUENTLY KEEP
THINGS MOVING AT A RAPID PACE. MOST OF THE CWA WILL REMAIN ON THE
NORTHERN SIDE OF THE JET WHICH WILL AID IN BRINGING SEVERAL
SHORTWAVES INTO SOUTH CENTRAL MONTANA THROUGH THE EXTENDED PERIOD.
TEMPERATURE FORECAST IS ON TRACK...WITH TEMPERATURES RETURNING TO
MORE NORMAL BY THE END OF THE WEEK.
BY SATURDAY...HOWEVER...ABUNDANT MOISTURE WILL BE AVAILABLE TO
BRING THE POTENTIAL FOR ANOTHER MUCH NEEDED PRECIPITATION EVENT AS
A FRONTAL SYSTEM MAKES ITS WAY ACROSS SOUTH CENTRAL MONTANA BY
SUNDAY AFTERNOON. EC SOLUTION HAS AN UPPER LEVEL LOW FORMING IN
NORTHEAST MONTANA. THIS PREFERRED SOLUTION WOULD BRING THE
AFOREMENTIONED PRECIPITATION EVENT TO MUCH OF SOUTHEASTERN
MONTANA. UPPED POPS TO REFLECT THIS...BUT THE EXACT PERIODS OF
PREFERENCE ARE NOT QUITE CLEAR AT THIS POINT. SINGER
&&
.AVIATION...
BIGGEST IMPACTS FOR AVIATION WILL BE REDUCED VISIBILITIES DUE TO
CONTINUATION OF LATE SEASON WINTER STORM. WIDESPREAD IFR
CONDITIONS WILL PERSIST THROUGH THE EVENING HOURS ESPECIALLY NEAR
KBIL...KMLS AND KBHK...DUE TO OCCASIONAL SNOW AND BLOWING SNOW.
NORTHERLY WINDS MAY GUST TO NEAR 25 KTS MAKING CONDITIONS WORSE AT
TIMES. KSHR WILL SEE POTENTIAL FOR SIGNIFICANT SNOWFALL AND AIR
TRAVEL IMPACTS THROUGH TOMORROW AFTERNOON. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
TUE WED THU FRI SAT SUN MON
-----------------------------------------------------------
BIL 015/033 017/044 031/054 032/053 031/055 032/053 029/052
+2/S 01/B 33/W 22/W 34/W 33/W 33/W
LVM 015/034 018/052 031/056 030/053 030/053 027/050 025/048
+2/S 01/B 32/W 22/W 34/W 33/W 33/W
HDN 017/032 015/043 027/053 028/053 026/056 029/054 026/052
+3/S 11/B 33/W 22/W 33/W 33/W 33/W
MLS 016/030 016/040 025/048 028/051 026/055 029/054 027/051
21/B 11/U 23/W 22/W 33/W 33/W 33/W
4BQ 010/028 013/036 021/044 024/049 024/053 027/052 024/049
+9/S 31/B 23/W 23/W 23/W 33/W 33/W
BHK 010/026 014/034 019/041 024/046 024/049 024/048 022/045
32/S 11/B 23/W 22/W 24/W 33/W 23/W
SHR 016/027 013/040 022/049 027/049 025/053 027/050 025/049
+9/S 21/B 23/W 23/W 23/W 43/W 44/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT TUESDAY FOR
ZONES 36>38.
WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MDT TUESDAY FOR
ZONES 56-66.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 9 PM MDT TUESDAY FOR
ZONE 58.
WY...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT TUESDAY FOR
ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
1135 AM MDT MON APR 8 2013
.SHORT TERM...VALID FOR TDY AND TUE...
WE WILL LET THE WINTER WEATHER ADVISORY FOR HARLOWTON...JUDITH GAP
AND ROUNDUP EXPIRE AS PLANNED AT 18 UTC. LIGHT SNOW CONTINUES OVER
THOSE AREAS...BUT SIGNIFICANT ACCUMULATIONS ARE OVER WITH AND ROAD
CONDITIONS ARE SLOWLY IMPROVING. THE REST OF THE ADVISORY AT MILES
CITY AND BAKER WILL REMAIN IN TACT FOR NOW.
AS LONG AS WE ARE UPDATING THE FORECAST...WE WILL INCREASE POPS IN
MOST PLACES TO 100 PERCENT FOR THE REST OF THE DAY BASED ON TRENDS
IN RADAR AND OBSERVATIONAL DATA AS OF 1730 UTC. SCHULTZ
PREVIOUS DISCUSSION...ISSUED AT 934 AM MDT MON APR 8 2013...
FRONTOGENETICALLY-INDUCED SNOW CONTINUES ITS TREK ACROSS SOUTHEAST
MT THIS MORNING...WITH VISIBILITY DOWN TO 1/4SM AT BAKER AT TIMES.
REPORTS IN THE WAKE OF THIS BAND OVERNIGHT WERE GENERALLY IN THE 3
TO 5 INCH RANGE FROM NEAR HARLOWTON TO ROUNDUP...FORSYTH AND MILES
CITY. THE 12 UTC NAM AND RECENT RAP RUNS SHOW THE FRONTOGENESIS IN
THE 850-700 HPA LAYER OVER SOUTHEASTERN MT WILL WEAKEN BY ABOUT 18
UTC AS THE BETTER FORCING SHIFTS INTO NORTH DAKOTA. THIS IDEA FITS
UPSTREAM TRENDS WELL WITH IMPROVING VISIBILITIES AT MILES CITY. IT
LOOKS LIKE WE WILL BE ABLE TO LET THE HARLOWTON AND JUDITH GAP TO
ROUNDUP PART OF THE WINTER WEATHER ADVISORY EXPIRE AS SCHEDULED AT
18 UTC. THE MILES CITY TO BAKER PART OF IT MIGHT BE DROPPED DURING
THE MID AFTERNOON...BUT GIVEN WEAK UPSLOPE SOME LIGHT SNOW WILL BE
GOING ON EVEN BEHIND THE MAIN BAND...SO WE PLAN TO BE SLOW TO DROP
THE HEADLINES GIVEN CONTINUED SLIPPERY ROADS.
ONLY MINOR CHANGES WERE MADE TO THE FORECAST WITH THIS UPDATE. THE
POPS AROUND SHERIDAN WERE REDUCED THIS MORNING BECAUSE THE FORCING
TIED TO THE EVOLVING 500-HPA TROUGH IN THE CENTRAL ROCKIES DOESN/T
LOOK TO REACH THERE UNTIL CLOSER TO 21 UTC. OTHERWISE...ONLY A FEW
OBSERVATIONALLY-BASED ADJUSTMENTS WERE MADE TO TODAY/S FORECAST AT
THIS POINT...INCLUDING LOWERING HIGHS A FEW DEGREES IN MOST SPOTS.
OUR MAIN FOCUS HEADING FORWARD WILL BE ON DETERMINING THE NORTHERN
EXTENT OF HEAVY SNOW TONIGHT AND TUESDAY...WITH POTENTIAL FOR 6 OR
MORE INCHES FROM SHERIDAN TO MOORHEAD AND ALBION. THE QPF FROM THE
12 UTC NAM STRONGLY SUPPORTS UPGRADING OUR WINTER STORM WATCH TO A
WARNING. HOWEVER...WE WILL TAKE A LOOK AT THE REMAINDER OF THE NEW
MORNING GUIDANCE BEFORE MAKING A DECISION ON HEADLINES TONIGHT AND
TUESDAY BY THE EARLY TO MID AFTERNOON. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
DRY WEDNESDAY WITH MODERATION IN TEMPERATURES WILL BE FOLLOWED BY
A PACIFIC FRONT OVERNIGHT WHICH WILL BRING A PREVALENT NORTHWEST
FLOW ON THURSDAY AND FRIDAY. BY SATURDAY THE FLOW BEGINS TO BACK
AS AN UPPER LOW OVER THE GULF OF ALASKA TRACKS SOUTHWARD ALONG THE
BC COAST. THIS PUSHES ANOTHER COLD FRONT THROUGH THE REGION
DURING THE WEEKEND. JET STREAM REMAINS SOUTH OF THE REGION FOR
EARLY NEXT WEEK WITH TEMPERATURES BELOW NORMAL.
BEST CHANCES FOR PRECIPITATON WILL BE WITH THE WEDNESDAY NIGHT
FRONT AND THEN AS THE FLOW BACKS DURING THE WEEKEND IN RESPONSE TO
THE BC LOW. NO PARTICULAR PERIOD LOOKS IMPRESSIVE AT THIS POINT
FOR SIGNIFICANT WIDESPREAD BUT UNSETTLED WEATHER SHOULD BE
EXPECTED AFTER WEDNESDAY. TEMPERATURES WILL REMAIN NEAR NORMAL
THURSDAY THROUGH SATURDAY BEFORE FALLING SUNDAY. BORSUM
&&
.AVIATION...
LATE SEASON WINTER STORM CONTINUES TO MOVE ACROSS CENTRAL AND
EASTERN MONTANA THIS MORNING. WIDESPREAD IFR CONDITIONS WILL
PERSIST THROUGH THE MORNING HOURS ESPECIALLY NEAR KMLS AND
KBHK...DUE TO SNOW AND FOGGY CONDITIONS. NORTHERLY WINDS MAY PICK
UP BY THIS AFTERNOON NEAR KMLS AND KBHK MAKING CONDITIONS WORSE AT
TIMES. SNOWFALL MAY INCREASE AT ALL TERMINALS AGAIN THIS AFTERNOON
AS WELL. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 028 015/036 019/045 030/056 034/053 032/053 030/052
+/S 31/B 01/B 33/W 22/W 33/W 33/W
LVM 030 015/037 021/049 030/053 030/051 029/050 027/049
+/S 41/B 01/B 32/W 22/W 33/W 33/W
HDN 030 017/035 015/045 026/057 029/054 027/054 027/054
9/S 41/B 11/B 33/W 22/W 33/W 33/W
MLS 029 016/032 016/041 023/052 028/052 028/052 026/052
+/S 21/B 11/B 23/W 22/W 33/W 32/W
4BQ 032 010/031 011/039 019/052 025/051 026/051 025/051
7/S 87/S 31/B 23/W 23/W 23/W 33/W
BHK 029 010/028 013/036 017/045 028/046 026/046 022/046
+/S 42/S 11/B 23/W 22/W 23/W 32/W
SHR 031 016/031 015/040 021/054 028/051 027/052 025/051
8/S 87/S 21/B 23/W 23/W 23/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MDT THIS
EVENING FOR ZONES 31>33.
WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONES 36-37.
WY...WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS BILLINGS MT
934 AM MDT MON APR 8 2013
.SHORT TERM...VALID FOR TDY AND TUE...
FRONTOGENETICALLY-INDUCED SNOW CONTINUES ITS TREK ACROSS SOUTHEAST
MT THIS MORNING...WITH VISIBILITY DOWN TO 1/4SM AT BAKER AT TIMES.
REPORTS IN THE WAKE OF THIS BAND OVERNIGHT WERE GENERALLY IN THE 3
TO 5 INCH RANGE FROM NEAR HARLOWTON TO ROUNDUP...FORSYTH AND MILES
CITY. THE 12 UTC NAM AND RECENT RAP RUNS SHOW THE FRONTOGENESIS IN
THE 850-700 HPA LAYER OVER SOUTHEASTERN MT WILL WEAKEN BY ABOUT 18
UTC AS THE BETTER FORCING SHIFTS INTO NORTH DAKOTA. THIS IDEA FITS
UPSTREAM TRENDS WELL WITH IMPROVING VISIBILITIES AT MILES CITY. IT
LOOKS LIKE WE WILL BE ABLE TO LET THE HARLOWTON AND JUDITH GAP TO
ROUNDUP PART OF THE WINTER WEATHER ADVISORY EXPIRE AS SCHEDULED AT
18 UTC. THE MILES CITY TO BAKER PART OF IT MIGHT BE DROPPED DURING
THE MID AFTERNOON...BUT GIVEN WEAK UPSLOPE SOME LIGHT SNOW WILL BE
GOING ON EVEN BEHIND THE MAIN BAND...SO WE PLAN TO BE SLOW TO DROP
THE HEADLINES GIVEN CONTINUED SLIPPERY ROADS.
ONLY MINOR CHANGES WERE MADE TO THE FORECAST WITH THIS UPDATE. THE
POPS AROUND SHERIDAN WERE REDUCED THIS MORNING BECAUSE THE FORCING
TIED TO THE EVOLVING 500-HPA TROUGH IN THE CENTRAL ROCKIES DOESN/T
LOOK TO REACH THERE UNTIL CLOSER TO 21 UTC. OTHERWISE...ONLY A FEW
OBSERVATIONALLY-BASED ADJUSTMENTS WERE MADE TO TODAY/S FORECAST AT
THIS POINT...INCLUDING LOWERING HIGHS A FEW DEGREES IN MOST SPOTS.
OUR MAIN FOCUS HEADING FORWARD WILL BE ON DETERMINING THE NORTHERN
EXTENT OF HEAVY SNOW TONIGHT AND TUESDAY...WITH POTENTIAL FOR 6 OR
MORE INCHES FROM SHERIDAN TO MOORHEAD AND ALBION. THE QPF FROM THE
12 UTC NAM STRONGLY SUPPORTS UPGRADING OUR WINTER STORM WATCH TO A
WARNING. HOWEVER...WE WILL TAKE A LOOK AT THE REMAINDER OF THE NEW
MORNING GUIDANCE BEFORE MAKING A DECISION ON HEADLINES TONIGHT AND
TUESDAY BY THE EARLY TO MID AFTERNOON. SCHULTZ
.LONG TERM...VALID FOR WED...THU...FRI...SAT...SUN...
DRY WEDNESDAY WITH MODERATION IN TEMPERATURES WILL BE FOLLOWED BY
A PACIFIC FRONT OVERNIGHT WHICH WILL BRING A PREVALENT NORTHWEST
FLOW ON THURSDAY AND FRIDAY. BY SATURDAY THE FLOW BEGINS TO BACK
AS AN UPPER LOW OVER THE GULF OF ALASKA TRACKS SOUTHWARD ALONG THE
BC COAST. THIS PUSHES ANOTHER COLD FRONT THROUGH THE REGION
DURING THE WEEKEND. JET STREAM REMAINS SOUTH OF THE REGION FOR
EARLY NEXT WEEK WITH TEMPERATURES BELOW NORMAL.
BEST CHANCES FOR PRECIPITATON WILL BE WITH THE WEDNESDAY NIGHT
FRONT AND THEN AS THE FLOW BACKS DURING THE WEEKEND IN RESPONSE TO
THE BC LOW. NO PARTICULAR PERIOD LOOKS IMPRESSIVE AT THIS POINT
FOR SIGNIFICANT WIDESPREAD BUT UNSETTLED WEATHER SHOULD BE
EXPECTED AFTER WEDNESDAY. TEMPERATURES WILL REMAIN NEAR NORMAL
THURSDAY THROUGH SATURDAY BEFORE FALLING SUNDAY. BORSUM
&&
.AVIATION...
LATE SEASON WINTER STORM CONTINUES TO MOVE ACROSS CENTRAL AND
EASTERN MONTANA THIS MORNING. WIDESPREAD IFR CONDITIONS WILL
PERSIST THROUGH THE MORNING HOURS ESPECIALLY NEAR KMLS AND
KBHK...DUE TO SNOW AND FOGGY CONDITIONS. NORTHERLY WINDS MAY PICK
UP BY THIS AFTERNOON NEAR KMLS AND KBHK MAKING CONDITIONS WORSE AT
TIMES. SNOWFALL MAY INCREASE AT ALL TERMINALS AGAIN THIS AFTERNOON
AS WELL. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
TDY TUE WED THU FRI SAT SUN
-------------------------------------------------------
BIL 028 015/036 019/045 030/056 034/053 032/053 030/052
+/S 31/B 01/B 33/W 22/W 33/W 33/W
LVM 030 015/037 021/049 030/053 030/051 029/050 027/049
8/S 41/B 01/B 32/W 22/W 33/W 33/W
HDN 030 017/035 015/045 026/057 029/054 027/054 027/054
9/S 41/B 11/B 33/W 22/W 33/W 33/W
MLS 029 016/032 016/041 023/052 028/052 028/052 026/052
+/S 21/B 11/B 23/W 22/W 33/W 32/W
4BQ 032 010/031 011/039 019/052 025/051 026/051 025/051
7/O 87/S 31/B 23/W 23/W 23/W 33/W
BHK 029 010/028 013/036 017/045 028/046 026/046 022/046
+/S 42/S 11/B 23/W 22/W 23/W 32/W
SHR 031 016/031 015/040 021/054 028/051 027/052 025/051
8/O 87/S 21/B 23/W 23/W 23/W 33/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER WEATHER ADVISORY IN EFFECT UNTIL NOON MDT TODAY FOR
ZONES 28-29-42-63.
WINTER WEATHER ADVISORY IN EFFECT UNTIL 6 PM MDT THIS EVENING
FOR ZONES 31>33.
WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONES 36-37.
WY...WINTER STORM WATCH IN EFFECT FROM 6 PM MDT THIS EVENING
THROUGH LATE TUESDAY NIGHT FOR ZONE 99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
322 PM CDT MON APR 8 2013
.SHORT TERM...TONIGHT THROUGH THURSDAY
STRONG SPRING STORM SYSTEM IS KNOCKING AT OUR DOOR...WITH ACTIVE
WEATHER EXPECTED FOR THE NEXT FEW DAYS. SUBJECTIVE 12Z UPPER AIR
ANALYSIS INDICATES UPPER-LEVEL TROUGH DEEPENING INTO A LOW OVER
THE GREAT BASIN...WITH 500MB HEIGHT FALLS UP TO 150M. ANOTHER
SHORTWAVE WAS ADVANCING ACROSS IA...WITH 70M HEIGHT FALLS
ASSOCIATED WITH IT. UPPER-LEVEL JET WAS STRONGEST ON THE BACK SIDE
OF THE DIGGING UPPER LOW..WITH UP TO 110KT ALONG THE PACIFIC
COAST. MOISTURE AXIS AT 850MB EXTENDED FROM TX THROUGH EASTERN
KS/WESTERN MO AS FAR NORTH AS THE NEB AND IA BORDERS...WTIH A
DEVELOPING LEE LOW IN SOUTEAST CO/OK PANDHANDLE/SOUTHWEST KS. SUB-
0C TEMPS AT 850MB EXTENDED FROM MT THROUGH ND INTO NORTHERNMOST
MN. RAP ANALYSIS AT 19Z INDICATED A SURFACE LOW IN SOUTHEAST
CO/NORTHEAST NM...WITH FRONTAL BOUNDARY EXTENDING FROM SOUTHWEST
NEB THROUGH NORTHEAST NEB AS COLD AIR BEGINS TO DESCEND OUT OF SD
WHILE WARM AIR ADVECTION CONTINUES AHEAD OF THE LOW.
MAIN FORECAST CONCERNS INCLUDE CONVECTIVE POTENTIAL THIS EVENING AND
TONIGHT AND IN THE SOUTHERN CWA THROUGH TUESDAY...AS WELL AS WINTER
WEATHER POTENTIAL IN THE NORTHWEST CWA EARLY TUESDAY MORNING THROUGH
WEDNESDAY. LINGERING CLOUDS ARE INHIBITING WARMING IN THE
SOUTH...WHICH MIGHT MAKE REACHING CONVECTIVE TEMPERATURE A
CHALLENGE. STORMS ARE LIKELY TO FIRE THIS AFTERNOON FURTHER WEST IN
KS...AND MOVE ACROSS NORTHERN KS/SOUTHERN NEB LATER THIS EVENING
THROUGH TONIGHT. MEANWHILE...COLD FRONT DESCENDING OUT OF SD IS
LIKELY TO REACH THE NORTHERN CWA THIS EVENING/TONIGHT...AND SHOULD
BEGIN TO SEE RAIN ALONG THAT FRONT AS WELL. HAVE INCLUDED THUNDER
MENTION EVERYWHERE THIS EVENING...BUT STARTED TO TAKE IT OUT OF THE
NORTHERN CWA AFTER MIDNIGHT. DOES APPEAR THAT SURFACE TEMPS WILL
REMAIN ABOVE FREEZING THROUGH THE NIGHT ACROSS THE AREA...AND THUS
HAVE INDICATED RAIN...BUT SHOULD COLD AIR ARRIVE FASTER THAN
FORECAST...MAY SEE A CHANGE TO WINTRY MIX A LITTLE EARLIER.
COLD AIR ADVECTION WILL CONTINUE TUESDAY IN THE NORTHERN CWA AS
FRONT SLOWLY DIGS THROUGH THE CWA. NORTHWESTERN CWA SHOULD FALL
BELOW FREEZING NEAR THE GROUND BY MID-MORNING TUESDAY...AND WITH
LINGERING MID-LEVEL WARM NOSE...WOULD EXPECT PRECIPITATION TO CHANGE
FROM RAIN TO FREEZING RAIN/SLEET. SOUNDINGS ARE ON THE FENCE ON
WHICH WAY TO GO WITH PRECIP TYPE...AND HAVE INCLUDED A MIX OF BOTH.
OBVIOUSLY...IF ONE PHASE DOMINATES...IMPACTS WILL BE SIGNIFICANTLY
DIFFERENT. DID MOVE BACK TIMING ON WINTER STORM WATCH TO BEGIN AT
12Z IN THE FAR NORTHWEST AND 15Z IN THE REMAINING COUNTIES...BUT
WILL LET THE NEXT SHIFT MAKE AN ASSESSMENT ON TEMPERATURE PROFILES
TO DETERMINE POSSIBLE CONVERSION TO WARNING OR ADVISORY. FURTHER
SOUTH...HAVE INCLUDED THUNDERSTORM MENTION IN THE SOUTHEASTERN CWA
AS FRONT IS LIKELY TO ARRIVE DURING THE AFTERNOON WHEN SOME
DESTABILIZATION HAS OCCURRED.
FOLLOWED MODEL SOUNDINGS PRETTY CLOSELY FOR PRECIP TYPE THROUGH
TUESDAY NIGHT...WITH MORE OF A NAM/SREF FLAVOR LEANING TOWARD
CONTINUED ZR/IP. GFS DID LEAN MORE TOWARD SNOW...BUT FOR NOW...HAVE
LEANED TO THE WARMER MID-LEVEL SOLUTION AS THE SLOW-MOVING SYSTEM
CONTINUES TO ALLOW MID-LEVEL WARM AIR ADVECTION AND TROWALING AHEAD
OF IT. MOST OF THE EASTERN HALF OF THE CWA IS PROGGED TO REMAIN
RAIN THROUGH WEDNESDAY...WHILE PRECIPITATION TRANSITIONS TO A MIX
WITH SNOW IN THE NORTHWEST CWA. DELAYED TRANSITION SHOULD HOLD DOWN
AMOUNTS FOR ANY FROZEN PRECIPITATION ACROSS MOST OF THE CWA...AS
PRECIP AMOUNTS ARE PROGGED TO DIMINISH QUITE A BIT ON WEDNESDAY
NIGHT BY THE TIME TEMPS ARE COLD ENOUGH TO ALLOW SNOW ACROSS THE
REST OF THE CWA. STILL...AS WITH ALL PRECIP TYPE ISSUES...THE LINE
BETWEEN PRECIP TYPES IS THIN...AND CONFIDENCE IS ALWAYS ON THE LOW
SIDE FOR THESE TRANSITIONS. AN EARLIER CHANGEOVER WITH COLDER MID-
LEVELS WOULD PRODUCE MORE SNOW ACROSS THE AREA. PRECIPITATION
SHOULD FINALLY BEGIN TO EXIT THE AREA BY THURSDAY...BUT DID LOWER
TEMPS BY SEVERAL DEGREES ON THURSDAY AS THE COLDEST 850MB TEMPS PASS
OVER THE AREA.
MAYES
.LONG TERM...THURSDAY NIGHT THROUGH MONDAY
TEMPERATURES SHOULD BEGIN A MODERATING TREND THROUGH LATE WEEK
AND INTO THE WEEKEND AS UPPER-LEVEL FLOW RETURNS TO ZONAL...WITH
TEMPERATURES RETURNING TO NEAR-NORMAL READINGS FOR THE WEEKEND.
MODEL BLENDS CONTINUE TO GIVE A SLIGHT CHANCE TO SMALL CHANCE OF
PRECIPITATION ON SATURDAY NIGHT THROUGH MONDAYNIGHT...BUT
CONFIDENCE IS VERY LOW AS MODELS CONTINUE TO EXHIBIT SIGNIFICANT
RUN TO RUN VARIABILITY IN THE TIMING OR LOCATION OF ANY RAIN.
PRECIPITATION WOULD NOT BE LIKELY DURING ALL OF THOSE
PERIODS...BUT RATHER OVER A NARROWER WINDOW BETWEEN SATURDAY NIGHT
AND MONDAY NIGHT.
MAYES/BOUSTEAD
&&
.AVIATION...
18Z TAFS FOR KOMA...KOFK...KLNK
IFR CONDITIONS WILL CONTINUE FOR ANOTHER HOUR OR TWO AT OMA/LNK
BEFORE THINGS START TO SCATTER OUT A BIT AND VISBY IMPROVES TO
VFR. VFR CONDITIONS WILL CONT THROUGH THE AFTN AT OFK. A WARM
FRONT WILL MOVE NORTH TODAY TOWARD THE OMA/LNK TAF SITES AND THIS
MAY BE A FOCUS FOR SOME LATE AFTN AND EVENING THUNDERSTORMS. DUE
TO TIMING AND CAP UNCERTAINTIES WE WILL NOT INCLUDE THUNDER IN THE
TAFS YET THIS EVENING...BUT THIS MAY BE NEEDED LATER. WE WILL
INCLUDE SHOWERS OVERNIGHT AT ALL 3 SITES THOUGH AS ACTIVITY TO
THE WEST SPREAD EASTWARD. WIDESPREAD IFR/LIFR CONDITIONS WILL
RETURN TONIGHT AS STRATUS DEVELOPS AS SOUTHERLY FLOW AGAIN
INCREASES. THE IFR CIGS SHOULD CONT THROUGH THE REST OF THIS TAF
PERIOD AT ALL SITES. MVFR VISBY IS ALSO LIKELY TO DEVELOP TOWARD
06Z AND CONT THROUGH THE REST OF THE TAF PERIOD.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ012-017-030-031.
WINTER STORM WATCH FROM TUESDAY MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ011-016.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
313 PM CDT MON APR 8 2013
.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
DEEP CONVECTION SHOULD DEVELOP WEST TO EAST TONIGHT WITH LARGE HAIL
THE PRIMARY SEVERE WEATHER THREAT. THERE IS A NARROW WINDOW FOR
TORNADOES ASSOCIATED WITH A SOUTHWARD MOVING COLD FRONT THIS EVENING
AND STORMS DEVELOPING ALONG OR JUST SOUTH OF THE FRONT. THE
THUNDERSTORMS WILL HELP PULL COLD AIR SOUTH WHICH COULD CAUSE A
CHANGEOVER TO FREEZING RAIN FASTER THAN FORECAST.
THE RAP HAS WEAKENED THE MIDLEVEL WARM AIR ADVECTION SUFFICIENTLY TO
REDUCE THE RISK OF SLEET HOWEVER THIS WOULD SUGGEST MORE FREEZING
RAIN OR FREEZING DRIZZLE POTENTIAL TUESDAY AS THE MOISTURE IS
GENERALLY BELOW 700 MB IN ALL MODELS. THE LATEST FORECAST SHOWS LESS
QPF TUESDAY BUT SOME AREAS COULD SEE BETWEEN 1/4 AND 1/2 INCH OF
FREEZING RAIN AS THE CHANGEOVER LINE WILL SPEND MOST OF THE DAY
HOURS TRAVERSING EASTERN PORTIONS OF THE FCST AREA.
THE SNOW LINE IS A LITTLE FASTER IN THE RAP BUT THE RAIN TO FREEZING
RAIN LINE SHOULD BE DRAPED ACROSS CUSTER AND FRONTIER COUNTY BY 12Z
TUESDAY. ALL OF THIS SUGGESTS THE COLD AIR IS WINNING OUT IN THE
WEST AND TAKING A MORE NORTH TO SOUTH PLUNGE. THERE NO REAL CHANGE
IN THE SNOWFALL AMOUNTS DURING THE SHORT TERM EXCEPT HIGHER AMOUNTS
ASSOCIATED WITH THE SLIGHTLY FASTER CHANGEOVER IN THE WEST.
ICING COULD BE A REAL PROBLEM FOR THE POWER GRID IN SOME AREAS WITH
WINDS INCREASING TO 25 TO 35 MPH. TEMPERATURES SHOULD BE STEADY OR
FALLING IN THE 20S THROUGHOUT THE DAY AND WIND CHILL READINGS IN THE
SINGLE DIGITS ARE EXPECTED ALL AREAS BY TUESDAY NIGHT.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 314 PM CDT MON APR 8 2013
EARLY TUESDAY EVENING THE H5 UPPER LOW IS FORECAST TO ROTATE INTO
CENTRAL COLORADO WHILE THE H7 LOW MOVES INTO FAR NORTHEAST CO/SWRN
NEBR/NWRN KS. THIS WILL BE CONDUCIVE FOR A PERIOD OF MODERATE TO
HEAVY SNOW IS TO DEVELOP IN NW KS AND DRAWN NORTHWARD INTO
WESTERN NEBRASKA. NORTHWEST WINDS 25 TO 35 MPH AND GUSTY TO
PRODUCE AREAS OF BLOWING SNOW TO DIMINISH SLIGHTLY TO 20 TO 30
MPH AFTER MIDNIGHT. THE SYSTEM WILL BEGIN TO WEAKEN AS DRIER AIR
IS DRAWN INTO THE EASTERN SIDE OF THE SYSTEM. A PERSISTENT
DEFORMATION ZONE ON THE BACKSIDE OF THE SYSTEM WILL STILL BRING
LIGHT SNOW ACCUMULATIONS LATE TUESDAY NIGHT THROUGH WEDNESDAY.
EVEN WEDNESDAY NIGHT INTO THURSDAY...THE NORTHEAST HALF OF THE
AREA MAY CONTINUE TO SEE LIGHT SNOW AS UPPER LOW ROTATES SLOWLY
EAST INTO IOWA.
HAVE TRENDED DOWN HIGH TEMPERATURES WEDNESDAY TO THE UPPER 20S AND
LOWER 30S. THURSDAY HIGHS ALSO TRENDED DOWN A BIT TO 33 TO 35
NORTH CENTRAL TO THE LOWER 40S FAR SOUTHWEST.
IN WAKE OF CLOSED SYSTEM THURSDAY...UPPER FLOW WILL BE WEST
NORTHWEST FRIDAY THROUGH MONDAY. TEMPERATURES TO MODERATE FROM
40 TO 50 FRIDAY TO THE 50S TO LOW/MID 60S SATURDAY AND SUNDAY. LOW
CHANCE POPS SUNDAY/MONDAY FOR RAIN SHOWERS...NIGHTTIME/MORNING
RAIN/SNOW SHOWERS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1251 CDT MON APR 8 2013
WINTER STORM CONDITIONS WITH WIDESPREAD IFR/LIFR SPREAD SOUTH AND
EAST THIS AFTERNOON THROUGH NOON TUESDAY. FLIGHT CONDITIONS
SLOWLY DETERIORATE FROM NORTH TO SOUTH THIS AFTERNOON AS STRATUS
DEVELOPS. THUNDERSTORM POTENTIAL BECOMES LIKELY ALONG INTERSTATE
80 AFTER 00Z THIS EVENING.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 AM CDT /3 AM MDT/ TUESDAY TO 7 AM
CDT /6 AM MDT/ WEDNESDAY FOR NEZ029-038-058-069>071.
WINTER STORM WARNING FROM 4 AM CDT /3 AM MDT/ TUESDAY TO 7 AM
CDT /6 AM MDT/ WEDNESDAY FOR NEZ006>010-024>028-035>037-056-057-
059.
WINTER STORM WARNING FROM 1 AM CDT /MIDNIGHT MDT/ TUESDAY TO 7
AM CDT /6 AM MDT/ WEDNESDAY FOR NEZ004-005-022-023-094.
&&
$$
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...CDC
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
753 PM EDT TUE APR 9 2013
.SYNOPSIS...
WEAK LOW PRESSURE SYSTEMS TO PASS TO OUR SOUTH TONIGHT AND
WEDNESDAY NIGHT WILL BRING SCATTERED RAIN SHOWERS TO THE NORTH
COUNTRY...ESPECIALLY ACROSS SOUTHERN VERMONT. A LARGER MORE
SIGNIFICANT LOW PRESSURE SYSTEM WILL APPROACH THE FORECAST AREA
FROM THE OHIO RIVER VALLEY THURSDAY NIGHT THROUGH FRIDAY BRINGING
MAINLY RAIN...THOUGH SOME SNOW IN THE MOUNTAINS...TO THE REGION.
TEMPERATURES WILL TREND COLDER TOWARDS THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
AS OF 706 PM EDT TUESDAY...SLOW-MOVING WARM FRONTAL BOUNDARY
POSITIONED OVER SOUTH-CENTRAL NEW YORK STATE HAS MADE SOME MODEST
NORTHWARD MOVEMENT OVER THE PAST COUPLE HOURS. REGIONAL RADAR
SHOWS BAND OF RAIN WITH EMBEDDED THUNDER ACROSS THE LOWER GREAT
LAKES...GENERALLY MOVING ALONG THE STRONGEST LOW- LEVEL THERMAL
GRADIENT ASSOCIATED WITH THE FRONTAL ZONE. THE RAIN IS ALSO BEING
ENHANCED BY A POTENT MID-LEVEL VORT MAX AS SUGGESTED BY WV
SATELLITE AND RAP ANALYSES. THE RAIN WILL SKIRT ACROSS THE NORTH
COUNTRY TONIGHT ALBEIT SLIGHTLY FURTHER SOUTH THAN LAST NIGHT.
EXPECT RAIN TO BEGIN IN THE NEXT HOUR OR SO ACROSS
CENTRAL/SOUTHERN SAINT LAWRENCE COUNTY AND THE
ADIRONDACKS...TOWARDS MIDNIGHT FOR THE CHAMPLAIN VALLEY...AND
ACROSS CENTRAL/EASTERN VERMONT AFTER MIDNIGHT. WILL NEED TO
MONITOR FOR POSSIBLE THUNDER MAINLY FOR SOUTHERN VERMONT...THOUGH
WARMING CLOUD TOPS AND MORE FAVORABLE/LOWER SHOWALTER INDICES
EXIST SOUTH OF THE WARM FRONT WOULD SUGGEST LEAVING THUNDER OUT OF
THE FORECAST.
CURRENT FORECAST SHOWS THESE TRENDS NICELY SO DIDN`T MAKE ANY
SIGNIFICANT CHANGES...THOUGH DID TWEAK ZONE FORECAST WORDING TO
SHOW RAIN INSTEAD OF RAIN SHOWERS. OTHERWISE MADE MINOR TWEAKS TO
TEMPERATURES/DEWPOINTS TO MATCH WITH CURRENT OBSERVATIONS.
PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 415 PM EDT FOLLOWS...
STATIONARY FRONT IS SET UP SOUTH OF OUR FORECAST AREA AND A LOW
PRESSURE SYSTEM TRAVELS MORE OR LESS ALONG THE FRONT OVERNIGHT. A
WEAK COLD FRONT OR SURFACE TROF DROPS NORTH TO SOUTH ACROSS OUR
FORECAST AREA OVERNIGHT...ALONG WITH A WEAK SHORTWAVE. THEREFORE
HAVE MENTIONED LIKELY SHOWERS OVERNIGHT...ESPECIALLY ACROSS OUR
SOUTHERN ZONES WHICH WILL BE CLOSER TO THE LOW CENTER. MINIMUM
TEMPERATURES WILL BE MILD OVERNIGHT DUE TO CLOUD COVER AND
PRECIPITATION...THEREFORE EXPECTING MAINLY JUST RAIN SHOWERS WITH
TEMPERATURES DIPPING INTO THE 40S AND UPPER 30S.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 430 PM EDT TUESDAY...TEMPERATURE GRADIENT REMAINS SITUATED
ACROSS OUR FORECAST AREA FROM WEDNESDAY THROUGH THURSDAY
NIGHT...THEREFORE A DIFFICULT FORECAST AS FAR AS TEMPERATURES AND
TYPE OF PRECIPITATION GOES. PRECIPITATION SHOULD HAVE PRETTY MUCH
CLEARED OUR FORECAST AREA BY WEDNESDAY MORNING. THERE WILL BE
ANOTHER BRIEF BREAK IN THE PRECIPITATION DURING THE DAYTIME HOURS
ON WEDNESDAY..THEN ANOTHER WEAK LOW PASSES TO OUR SOUTH ALONG THE
STATIONARY BOUNDARY. WILL HAVE ANOTHER CHANCE FOR RAIN SHOWERS
ACROSS OUR SOUTHERN ZONES...THOUGH TEMPERATURES DROP FURTHER
WEDNESDAY NIGHT AS TEMPERATURE GRADIENT SINKS SOUTH SLIGHTLY.
DURING THE DAY THURSDAY NEXT LOW PRESSURE SYSTEM TO IMPACT THE
NORTH COUNTRY WILL APPROACH FROM THE OHIO RIVER VALLEY. THERE
WILL BE A CHANCE FOR RAIN THURSDAY AS WARM AIR ADVECTION AND
UPPER LEVEL SHORTWAVE MOVE ACROSS THE AREA. PRECIPITATION
CONTINUES THURSDAY NIGHT...THOUGH P-TYPE IS A TOUGH CALL DUE TO
TEMPERATURE GRADIENT STILL SITUATED ACROSS OUR FORECAST AREA.
THINK IT WILL BE MAINLY RAIN IN THE VALLEYS...WITH SOME SNOW AND
SLEET IN THE HIGHER ELEVATIONS. THERE IS A SMALL CHANCE FOR SOME
FREEZING RAIN IN THE SMALLER VALLEYS THROUGHOUT THE DACKS AND
GREENS. THURSDAY AND THURSDAY NIGHT HAVE MENTIONED CATEGORICAL
POPS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 323 PM EDT TUESDAY...HEADING INTO FRIDAY...A LARGE UPPER
LEVEL TROUGH WILL BE POSITIONED OVER THE GREAT LAKES WITH STRONG
SOUTHWEST FLOW ALOFT BRINGING IN ABUNDANT MOISTURE. A SHARP
BAROCLINIC ZONE WILL REMAIN NEAR THE REGION WITH A SHARP
TEMPERATURE GRADIENT AND STRONG WARM AIR ADVECTION OCCURRING. THE
EXACT PLACEMENT OF THIS FRONTAL BOUNDARY WILL BE CRITICAL TO HOW
THE WEATHER FOR THURSDAY NIGHT AND FRIDAY PLAYS OUT. A SURFACE
LOW WILL TRACK ALONG THE GRADIENT ON FRIDAY...POSSIBLY
REDEVELOPING ALONG THE NEW ENGLAND COASTLINE BEFORE PULLING AWAY
FROM THE REGION ON FRIDAY NIGHT. WEST TO NORTHWEST FLOW WILL
RETURN FOR FRIDAY NIGHT AND SATURDAY...FOLLOWED BY A BUILDING
RIDGE FOR SUNDAY AND SUNDAY NIGHT. THE NEXT SYSTEM APPROACHES FOR
MONDAY AND TUESDAY AS A RIDGE BUILDS OFF THE SOUTHEASTERN UNITED
STATES COAST AND A FRONTAL BOUNDARY SAGS SOUTHWARD ACROSS THE
REGION. DETAILS FOLLOW BELOW.
FOR FRIDAY...AS MENTIONED...PLACEMENT OF FRONTAL BOUNDARY WILL BE
CRUCIAL FOR AMOUNT AND TYPE OF PRECIPITATION. THE NAM IS FURTHEST
SOUTH...FOLLOWED BY THE ECMWF AND THEN THE GFS. WILL LEAN TOWARDS
A FURTHER NORTH AND THEREFORE WARMER SOLUTION WITH PERIODS OF
RAIN/SLEET/SNOW FRIDAY MORNING TRANSITIONING TO ALL RAIN BY
FRIDAY AFTERNOON. WILL SEE SOME SOUTHEASTERLY DOWNSLOPE/UPSLOPE
EFFECTS AS WELL WITH LOW LEVEL SOUTHEAST WINDS. HOWEVER NOT
EXPECTING ANY SIGNIFICANT DOWNSLOPE WIND EFFECTS AT THIS TIME AS
MAGNITUDE OF LOW LEVEL WINDS NOT EXPECTED TO BE LARGE ENOUGH.
ADDITIONAL QPF ON FRIDAY WILL GENERALLY BE A QUARTER TO A HALF
INCH...BRINGING TOTAL THURSDAY-FRIDAY RAIN AMOUNTS FROM 0.5-1.5".
THE COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM PASSES
FRIDAY EVENING WITH FALLING TEMPERATURES AND WESTERLY WINDS FOR
FRIDAY NIGHT. WESTERLY FLOW CONTINUES ON SATURDAY AS UPPER TROUGH
REMAINS OVERHEAD. WILL LIKELY SEE SOME LINGERING SCATTERED RAIN
AND MOUNTAIN SNOW SHOWERS THROUGH SATURDAY.
A RIDGE BEGINS TO BUILD ACROSS THE AREA BY SUNDAY WITH MODERATING
TEMPERATURES ALOFT. THIS SHOULD RESULT IN SUNDAY BEING THE NICEST
DAY OF THE PERIOD WITH MOSTLY SUNNY SKIES AND TEMPERATURES IN THE
40S TO AROUND 50 DEGREES.
STRONG WARM AIR ADVECTION RETURNS FOR SUNDAY NIGHT AS A RIDGE
BEGINS TO BUILD OFF THE SOUTHEASTERN US COAST. AS THE RIDGE
BUILDS...A COLD FRONT MAY TRY TO SAG SOUTHWARD ACROSS THE REGION
FOR MONDAY AND TUESDAY...BRINGING ANOTHER CHANCE OF RAIN SHOWERS.
TEMPERATURES WILL HAVE MODERATED BACK INTO THE 50S TO NEAR 60 FOR
HIGHS AND 30S TO AROUND 40 FOR LOWS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 00Z THURSDAY...VFR CONDITIONS THIS EVENING WILL BE LOWERING
TO MVFR AND POSSIBLY IFR AT TIMES OVERNIGHT. WEAK LOW PRESSURE
PASSING SOUTH OF THE AREA WILL BRING A PERIOD OF RAIN TO THE
REGION...WHICH WILL DEVELOP FROM WEST TO EAST ACROSS THE AREA
BETWEEN 02Z-05Z AND EXIT BETWEEN 08Z-12Z. WHILE VSBYS WILL IMPROVE
WITH THE END OF ANY RAIN...CIGS WILL REMAIN MOSTLY MVFR THROUGH
ABOUT 18Z WEDNESDAY BEFORE IMPROVING TO VFR. LIGHT AND VARIABLE
WINDS TONIGHT WILL BECOME NNW 5-10 KNOTS WEDNESDAY.
OUTLOOK 00Z THURSDAY THROUGH SUNDAY...
00Z THURSDAY THROUGH THURSDAY...OCCASIONAL SHOWERS AND/OR PERIODS
OF RAIN CAN BE EXPECTED AS A SURFACE FRONT STALLS JUST SOUTH OF
THE AREA...REDUCING CONDITIONS TO MVFR WITH PERIODS OF IFR.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...CONTINUED UNSETTLED WITH
PASSAGE OF LOW PRESSURE AND WIDESPREAD RAINFALL...POSSIBLY HEAVY.
MVFR/IFR CONDITIONS LIKELY.
SATURDAY AND SUNDAY...CONDITIONS IMPROVING TO MAINLY VFR WITH
SCATTERED MVFR SHOWERS POSSIBLE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NEILES
NEAR TERM...NEILES/LOCONTO
SHORT TERM...NEILES
LONG TERM...MUCCILLI
AVIATION...RJS/JN
AREA FORECAST DISCUSSION
NWS BURLINGTON VT
706 PM EDT TUE APR 9 2013
.SYNOPSIS...
WEAK LOW PRESSURE SYSTEMS TO PASS TO OUR SOUTH TONIGHT AND
WEDNESDAY NIGHT WILL BRING SCATTERED RAIN SHOWERS TO THE NORTH
COUNTRY...ESPECIALLY ACROSS SOUTHERN VERMONT. A LARGER MORE
SIGNIFICANT LOW PRESSURE SYSTEM WILL APPROACH THE FORECAST AREA
FROM THE OHIO RIVER VALLEY THURSDAY NIGHT THROUGH FRIDAY BRINGING
MAINLY RAIN...THOUGH SOME SNOW IN THE MOUNTAINS...TO THE REGION.
TEMPERATURES WILL TREND COLDER TOWARDS THE END OF THE WEEK.
&&
.NEAR TERM /UNTIL 8 AM WEDNESDAY MORNING/...
AS OF 706 PM EDT TUESDAY...SLOW-MOVING WARM FRONTAL BOUNDARY
POSITIONED OVER SOUTH-CENTRAL NEW YORK STATE HAS MADE SOME MODEST
NORTHWARD MOVEMENT OVER THE PAST COUPLE HOURS. REGIONAL RADAR
SHOWS BAND OF RAIN WITH EMBEDDED THUNDER ACROSS THE LOWER GREAT
LAKES...GENERALLY MOVING ALONG THE STRONGEST LOW- LEVEL THERMAL
GRADIENT ASSOCIATED WITH THE FRONTAL ZONE. THE RAIN IS ALSO BEING
ENHANCED BY A POTENT MID-LEVEL VORT MAX AS SUGGESTED BY WV
SATELLITE AND RAP ANALYSES. THE RAIN WILL SKIRT ACROSS THE NORTH
COUNTRY TONIGHT ALBEIT SLIGHTLY FURTHER SOUTH THAN LAST NIGHT.
EXPECT RAIN TO BEGIN IN THE NEXT HOUR OR SO ACROSS
CENTRAL/SOUTHERN SAINT LAWRENCE COUNTY AND THE
ADIRONDACKS...TOWARDS MIDNIGHT FOR THE CHAMPLAIN VALLEY...AND
ACROSS CENTRAL/EASTERN VERMONT AFTER MIDNIGHT. WILL NEED TO
MONITOR FOR POSSIBLE THUNDER MAINLY FOR SOUTHERN VERMONT...THOUGH
WARMING CLOUD TOPS AND MORE FAVORABLE/LOWER SHOWALTER INDICES
EXIST SOUTH OF THE WARM FRONT WOULD SUGGEST LEAVING THUNDER OUT OF
THE FORECAST.
CURRENT FORECAST SHOWS THESE TRENDS NICELY SO DIDN`T MAKE ANY
SIGNIFICANT CHANGES...THOUGH DID TWEAK ZONE FORECAST WORDING TO
SHOW RAIN INSTEAD OF RAIN SHOWERS. OTHERWISE MADE MINOR TWEAKS TO
TEMPERATURES/DEWPOINTS TO MATCH WITH CURRENT OBSERVATIONS.
PREVIOUS NEAR-TERM DISCUSSION ISSUED AT 415 PM EDT FOLLOWS...
STATIONARY FRONT IS SET UP SOUTH OF OUR FORECAST AREA AND A LOW
PRESSURE SYSTEM TRAVELS MORE OR LESS ALONG THE FRONT OVERNIGHT. A
WEAK COLD FRONT OR SURFACE TROF DROPS NORTH TO SOUTH ACROSS OUR
FORECAST AREA OVERNIGHT...ALONG WITH A WEAK SHORTWAVE. THEREFORE
HAVE MENTIONED LIKELY SHOWERS OVERNIGHT...ESPECIALLY ACROSS OUR
SOUTHERN ZONES WHICH WILL BE CLOSER TO THE LOW CENTER. MINIMUM
TEMPERATURES WILL BE MILD OVERNIGHT DUE TO CLOUD COVER AND
PRECIPITATION...THEREFORE EXPECTING MAINLY JUST RAIN SHOWERS WITH
TEMPERATURES DIPPING INTO THE 40S AND UPPER 30S.
&&
.SHORT TERM /8 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
AS OF 430 PM EDT TUESDAY...TEMPERATURE GRADIENT REMAINS SITUATED
ACROSS OUR FORECAST AREA FROM WEDNESDAY THROUGH THURSDAY
NIGHT...THEREFORE A DIFFICULT FORECAST AS FAR AS TEMPERATURES AND
TYPE OF PRECIPITATION GOES. PRECIPITATION SHOULD HAVE PRETTY MUCH
CLEARED OUR FORECAST AREA BY WEDNESDAY MORNING. THERE WILL BE
ANOTHER BRIEF BREAK IN THE PRECIPITATION DURING THE DAYTIME HOURS
ON WEDNESDAY..THEN ANOTHER WEAK LOW PASSES TO OUR SOUTH ALONG THE
STATIONARY BOUNDARY. WILL HAVE ANOTHER CHANCE FOR RAIN SHOWERS
ACROSS OUR SOUTHERN ZONES...THOUGH TEMPERATURES DROP FURTHER
WEDNESDAY NIGHT AS TEMPERATURE GRADIENT SINKS SOUTH SLIGHTLY.
DURING THE DAY THURSDAY NEXT LOW PRESSURE SYSTEM TO IMPACT THE
NORTH COUNTRY WILL APPROACH FROM THE OHIO RIVER VALLEY. THERE
WILL BE A CHANCE FOR RAIN THURSDAY AS WARM AIR ADVECTION AND
UPPER LEVEL SHORTWAVE MOVE ACROSS THE AREA. PRECIPITATION
CONTINUES THURSDAY NIGHT...THOUGH P-TYPE IS A TOUGH CALL DUE TO
TEMPERATURE GRADIENT STILL SITUATED ACROSS OUR FORECAST AREA.
THINK IT WILL BE MAINLY RAIN IN THE VALLEYS...WITH SOME SNOW AND
SLEET IN THE HIGHER ELEVATIONS. THERE IS A SMALL CHANCE FOR SOME
FREEZING RAIN IN THE SMALLER VALLEYS THROUGHOUT THE DACKS AND
GREENS. THURSDAY AND THURSDAY NIGHT HAVE MENTIONED CATEGORICAL
POPS.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 323 PM EDT TUESDAY...HEADING INTO FRIDAY...A LARGE UPPER
LEVEL TROUGH WILL BE POSITIONED OVER THE GREAT LAKES WITH STRONG
SOUTHWEST FLOW ALOFT BRINGING IN ABUNDANT MOISTURE. A SHARP
BAROCLINIC ZONE WILL REMAIN NEAR THE REGION WITH A SHARP
TEMPERATURE GRADIENT AND STRONG WARM AIR ADVECTION OCCURRING. THE
EXACT PLACEMENT OF THIS FRONTAL BOUNDARY WILL BE CRITICAL TO HOW
THE WEATHER FOR THURSDAY NIGHT AND FRIDAY PLAYS OUT. A SURFACE
LOW WILL TRACK ALONG THE GRADIENT ON FRIDAY...POSSIBLY
REDEVELOPING ALONG THE NEW ENGLAND COASTLINE BEFORE PULLING AWAY
FROM THE REGION ON FRIDAY NIGHT. WEST TO NORTHWEST FLOW WILL
RETURN FOR FRIDAY NIGHT AND SATURDAY...FOLLOWED BY A BUILDING
RIDGE FOR SUNDAY AND SUNDAY NIGHT. THE NEXT SYSTEM APPROACHES FOR
MONDAY AND TUESDAY AS A RIDGE BUILDS OFF THE SOUTHEASTERN UNITED
STATES COAST AND A FRONTAL BOUNDARY SAGS SOUTHWARD ACROSS THE
REGION. DETAILS FOLLOW BELOW.
FOR FRIDAY...AS MENTIONED...PLACEMENT OF FRONTAL BOUNDARY WILL BE
CRUCIAL FOR AMOUNT AND TYPE OF PRECIPITATION. THE NAM IS FURTHEST
SOUTH...FOLLOWED BY THE ECMWF AND THEN THE GFS. WILL LEAN TOWARDS
A FURTHER NORTH AND THEREFORE WARMER SOLUTION WITH PERIODS OF
RAIN/SLEET/SNOW FRIDAY MORNING TRANSITIONING TO ALL RAIN BY
FRIDAY AFTERNOON. WILL SEE SOME SOUTHEASTERLY DOWNSLOPE/UPSLOPE
EFFECTS AS WELL WITH LOW LEVEL SOUTHEAST WINDS. HOWEVER NOT
EXPECTING ANY SIGNIFICANT DOWNSLOPE WIND EFFECTS AT THIS TIME AS
MAGNITUDE OF LOW LEVEL WINDS NOT EXPECTED TO BE LARGE ENOUGH.
ADDITIONAL QPF ON FRIDAY WILL GENERALLY BE A QUARTER TO A HALF
INCH...BRINGING TOTAL THURSDAY-FRIDAY RAIN AMOUNTS FROM 0.5-1.5".
THE COLD FRONT ASSOCIATED WITH THE LOW PRESSURE SYSTEM PASSES
FRIDAY EVENING WITH FALLING TEMPERATURES AND WESTERLY WINDS FOR
FRIDAY NIGHT. WESTERLY FLOW CONTINUES ON SATURDAY AS UPPER TROUGH
REMAINS OVERHEAD. WILL LIKELY SEE SOME LINGERING SCATTERED RAIN
AND MOUNTAIN SNOW SHOWERS THROUGH SATURDAY.
A RIDGE BEGINS TO BUILD ACROSS THE AREA BY SUNDAY WITH MODERATING
TEMPERATURES ALOFT. THIS SHOULD RESULT IN SUNDAY BEING THE NICEST
DAY OF THE PERIOD WITH MOSTLY SUNNY SKIES AND TEMPERATURES IN THE
40S TO AROUND 50 DEGREES.
STRONG WARM AIR ADVECTION RETURNS FOR SUNDAY NIGHT AS A RIDGE
BEGINS TO BUILD OFF THE SOUTHEASTERN US COAST. AS THE RIDGE
BUILDS...A COLD FRONT MAY TRY TO SAG SOUTHWARD ACROSS THE REGION
FOR MONDAY AND TUESDAY...BRINGING ANOTHER CHANCE OF RAIN SHOWERS.
TEMPERATURES WILL HAVE MODERATED BACK INTO THE 50S TO NEAR 60 FOR
HIGHS AND 30S TO AROUND 40 FOR LOWS.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 18Z WEDNESDAY...COND WILL RANGE FROM VFR DOWN IFR AT
TIMES...ESPECIALLY FOR SLK/MSS. PRECIPITATION/FG ROLL INTO AREA
AFT 04Z-06Z FROM WEST TO EAST. VSBY IN RW/FG WILL RANGE FROM
2-5SM W/ SOME LINGERING VCSH AFT 12Z WED. WINDS WNW 5-15KTS W/
GUSTS TO 25 KTS AT RUT...ALL BECM LGT/VAR BY 04Z-06Z W/ APPROACH
OF FRNTL BOUNDARY. AFT 12Z-14Z WED...WINDS BECM NNW 5-10KTS.
OUTLOOK 18Z WEDNESDAY THROUGH SUNDAY...
18Z WEDNESDAY THROUGH THURSDAY...OCCASIONAL SHOWERS AND/OR
PERIODS OF RAIN WILL DEVELOP AS A SURFACE FRONT STALLS OVER OR
JUST SOUTH OF THE AREA...REDUCING CONDITIONS TO MVFR WITH PERIODS
OF IFR.
THURSDAY NIGHT THROUGH FRIDAY NIGHT...CONTINUED UNSETTLED WITH
PASSAGE OF LOW PRESSURE AND WIDESPREAD RAINFALL...POSSIBLY HEAVY.
MVFR/IFR CONDITIONS LIKELY.
SATURDAY AND SUNDAY...IMPROVING CONDITIONS TO MAINLY VFR WITH
SCATTERED MVFR SHOWERS POSSIBLE.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.
&&
$$
SYNOPSIS...NEILES
NEAR TERM...NEILES/LOCONTO
SHORT TERM...NEILES
LONG TERM...MUCCILLI
AVIATION...LAHIFF/JN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1215 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1207 PM CDT MON APR 8 2013
OTHER THAN THE FREEZING RAIN AND DRIZZLE ENDING NORTH DUE TO THE
PRESENCE OF ICE CRYSTALS ALOFT...THE CURRENT HEADLINES AREAS LOOK
GOOD FOR THE AFTERNOON. BOWMAN RADAR DOES SHOW THE BEGINNING OF
THE BACK EDGE OF MODERATE TO HEAVY SNOW. THIS SUGGESTS THE PERIOD
OF VERY HEAVY SNOW ACROSS THE SOUTHWEST MAY TRANSITION TO
CONTINUOUS LIGHT TO OCCASIONAL MODERATE SNOW...WITH MUCH OF THE
ACCUMULATIONS FALLING BY 7 PM. WILL KEEP THE HEADLINES GONG
THROUGH MIDNIGHT FOR RESIDUAL SNOW DURING THE EVENING.
UPDATE ISSUED AT 944 AM CDT MON APR 8 2013
UPGRADING TO WINTER STORM WARNING FOR HEAVY SNOW SOUTHWEST
COUNTIES OF GOLDEN VALLEY...BILLINGS...STARK...DUNN...HETTINGER
MCKENZIE...SLOPE. RADAR ANS SURFACE REPORTS SHOW BAND OF HEAVY
SNOW WILL EXTEND ACROSS THE SOUTHWEST. MOST OF THE HEAVY SNOW WILL
FALL THROUGH EARLY AFTERNOON THEN BEGIN TO DIMINISH.
UPDATE ISSUED AT 650 AM CDT MON APR 8 2013
SURFACE OBSERVATIONS AT STANLEY...MINOT AIR FORCE BASE AND BELCOURT
ARE INDICATING FREEZING RAIN. ALSO A REPORT OF FREEZING RAIN AND
SLEET AT LANSFORD. FORECAST SOUNDINGS INDICATE THIS SHOULD BE A
SHORT LIVED EVENT...WITH COLUMN CONTINUING TO COOL. THERE WAS ALSO
RAIN LAST NIGHT THAT HAS NOW FROZEN TO SURFACES. WILL ISSUE A
FREEZING RAIN ADVISORY TO COVER THE ICY CONDITIONS THROUGH THE
MORNING COMMUTE. WILL GO THROUGH NOON AND LET THE DAY SHIFT CANCEL
IF NEEDED.
SNOW CONTINUES TO LIFT NORTH AND EAST THROUGH SOUTHWEST NORTH
DAKOTA. NO CHANGES TO THE SNOW AND BLOWING SNOW ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 944 AM CDT MON APR 8 2013
WIDESPREAD IFR CONDITIONS ACROSS SOUTHWEST NORTH DAKOTA THROUGH 00Z.
HEAVY SNOW AND BLOWING SNOW KDIK. LIGHT SNOW KISN-KMOT-KDIK-KJMS
WITH IFR KBIS-KJMS. CONDITIONS IMPROVING TO MVFR TO VFR KISN-
KMOT LATE AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ009-019-020-034-042>044.
WINTER STORM WARNING UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY FOR
NDZ017-018-031>033-040-041.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
955 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 944 AM CDT MON APR 8 2013
UPGRADING TO WINTER STORM WARNING FOR HEAVY SNOW SOUTHWEST
COUNTIES OF GOLDEN VALLEY...BILLINGS...STARK...DUNN...HETTINGER
MCKENZIE...SLOPE. RADAR ANS SURFACE REPORTS SHOW BAND OF HEAVY
SNOW WILL EXTEND ACROSS THE SOUTHWEST. MOST OF THE HEAVY SNOW WILL
FALL THROUGH EARLY AFTERNOON THEN BEGIN TO DIMINISH.
UPDATE ISSUED AT 650 AM CDT MON APR 8 2013
SURFACE OBSERVATIONS AT STANLEY...MINOT AIR FORCE BASE AND BELCOURT
ARE INDICATING FREEZING RAIN. ALSO A REPORT OF FREEZING RAIN AND
SLEET AT LANSFORD. FORECAST SOUNDINGS INDICATE THIS SHOULD BE A
SHORT LIVED EVENT...WITH COLUMN CONTINUING TO COOL. THERE WAS ALSO
RAIN LAST NIGHT THAT HAS NOW FROZEN TO SURFACES. WILL ISSUE A
FREEZING RAIN ADVISORY TO COVER THE ICY CONDITIONS THROUGH THE
MORNING COMMUTE. WILL GO THROUGH NOON AND LET THE DAY SHIFT CANCEL
IF NEEDED.
SNOW CONTINUES TO LIFT NORTH AND EAST THROUGH SOUTHWEST NORTH
DAKOTA. NO CHANGES TO THE SNOW AND BLOWING SNOW ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 944 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 12 UTC TAF PERIOD.
WIDESPREAD LOW IFR TO IFR CONDITIONS ACROSS WEST AND CENTRAL NORTH
DAKOTA. HEAVY SNOW AND BLOWING SNOW KDIK. LIGHT SNOW KISN-KMOT-
KDIK-KJMS.
SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON/EVENING FOR ALL
BUT KJMS-KDIK AND POSSIBLY KBIS WHICH MAY REMAIN IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ009-019-020-034-042>044.
WINTER STORM WARNING UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY FOR
NDZ017-018-031>033-040-041.
FREEZING RAIN ADVISORY UNTIL NOON CDT TODAY FOR NDZ003>005-
010>013.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS BISMARCK ND
650 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 650 AM CDT MON APR 8 2013
SURFACE OBSERVATIONS AT STANLEY...MINOT AIR FORCE BASE AND BELCOURT
ARE INDICATING FREEZING RAIN. ALSO A REPORT OF FREEZING RAIN AND
SLEET AT LANSFORD. FORECAST SOUNDINGS INDICATE THIS SHOULD BE A
SHORT LIVED EVENT...WITH COLUMN CONTINUING TO COOL. THERE WAS ALSO
RAIN LAST NIGHT THAT HAS NOW FROZEN TO SURFACES. WILL ISSUE A
FREEZING RAIN ADVISORY TO COVER THE ICY CONDITIONS THROUGH THE
MORNING COMMUTE. WILL GO THROUGH NOON AND LET THE DAY SHIFT CANCEL
IF NEEDED.
SNOW CONTINUES TO LIFT NORTH AND EAST THROUGH SOUTHWEST NORTH
DAKOTA. NO CHANGES TO THE SNOW AND BLOWING SNOW ADVISORY.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 126Z MONDAY NIGHT)
ISSUED AT 650 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 06 UTC TAF PERIOD. LATEST
SATELLITE IMAGERY HAS SHOWN LIFR TO IFR CONDITIONS IN STRATUS AND
FOG. LIFR TO IFR CEILINGS ARE EXPECTED TO CONTINUE THROUGH
DAYBREAK...AND THEN IMPROVE TO IFR TO MARGINAL MVFR.
LOW PRESSURE ACROSS MONTANA WILL DEVELOP AND SNOW WITH SLEET AND
FREEZING RAIN WILL BEGIN TO IMPACT KDIK AFTER 12Z...SPREADING
EAST MONDAY MORNING IMPACTING OTHER TERMINALS. VISIBILITIES IN
SNOW AND BLOWING SNOW WILL LIKELY FALL TO IFR AND BELOW FOR KDIK-
KBIS. SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON FOR ALL BUT
KJMS- KDIK AND POSSIBLY KBIS WHICH MAY REMAIN MVFR-IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ017>020-031>034-040>044.
FREEZING RAIN ADVISORY UNTIL NOON CDT TODAY FOR NDZ003>005-
010>013.
&&
$$
UPDATE...TWH
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
408 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
UPCOMING STORM SYSTEM SET TO IMPACT WESTERN AND CENTRAL NORTH DAKOTA
TODAY AND INTO TONIGHT. ADDITIONALLY...WINTER WEATHER HEADLINES WILL
NEED TO EVALUATED IN ORDER TO DETERMINE WHETHER OR NOT CHANGES ARE
WARRANTED.
THE 00Z MODEL GUIDANCE CONTINUES TO HAVE SOME DISAGREEMENT REGARDING THE
AMOUNT OF QPF OVER THE IMPACTED AREA...INTRODUCING UNCERTAINTY INTO
THE QPF AND TOTAL SNOWFALL FORECAST. THE 00Z NAM/GFS ARE SIMILAR IN
THEIR SOLUTIONS PAINTING HEAVIER QPF AMOUNTS ACROSS THE SOUTHWEST
AND PARTS OF THE CENTRAL... WHILE THE 00Z ECMWF/GEM ARE
DRIER...KEEPING THE HEAVIEST QPF AMOUNTS FURTHER SOUTH OVER SOUTH
DAKOTA. IN REGARDS TO TIMING...ALL MENTIONED MODEL GUIDANCE HAS THE
HEAVIEST SNOWFALL OCCURRING BETWEEN 12Z AND 00Z TUESDAY. SNOWFALL
INTENSITY WILL DECREASE FROM NORTH TO SOUTH AFTER 00Z...AS LIGHT
SNOW ENDS AFTER 06Z TUESDAY. HOWEVER...ALONG THE ND/SD STATE
BORDER...LIGHT SNOW WILL CONTINUE THROUGH THE END OF THE PERIOD...AS
A SHARP PRECIPITATION GRADIENT SETS UP.
THE 00Z NAM/GFS...12Z ECMWF...AND THE LATEST RAP RUN AGREE ON THE
OVERALL THERMAL PROFILE. A COLD FRONT IS FORECAST TO DROP
SOUTH OUT OF CANADA...WITH COLDER H850 TEMPERATURES OF -10 TO -14 C
FORECAST TO MOVE OVER THE AREA. TEMPERATURES REMAIN FAIRLY WARM THIS
MORNING...MOSTLY ABOVE FREEZING FOR LOCATIONS ACROSS THE
SOUTHWEST...WHERE PRECIPITATION WILL BE INITIALLY LIGHT RAIN. A
QUICK TRANSITION TO SNOW WILL OCCUR BY DAYBREAK AS TEMPERATURES COOL
QUICKLY ACROSS THE SOUTHWEST.
AFTER WADING THROUGH THE 00Z MODEL GUIDANCE...HAVE DECIDED TO LEAN
MORE TOWARDS THE ECMWF SOLUTION...AS IT HAS HAD MORE RUN TO RUN
CONSISTENCY THAN THE NAM/GFS/GEM AS WELL AS HAVING SUPERIOR
PERFORMANCE THIS PAST WINTER. GIVEN THE AMOUNT OF UNCERTAINTY THAT
REMAINS AS THIS EVENT IS JUST GETTING UNDERWAY...HAVE DECIDED TO
KEEP WINTER WEATHER HEADLINES AS IS. SERIOUS CONSIDERATION WAS
GIVEN TO THE ISSUANCE OF A WINTER STORM WARNING FOR SNOW FOR
GOLDEN VALLEY...BILLINGS...DUNN...STARK...AND SLOPE COUNTIES WHERE
THE GREATEST SNOWFALL TOTALS ARE EXPECTED TO OCCUR.
ALSO...CONSIDERATION WAS GIVEN TO EXPANDING THE CURRENT ADVISORY
FURTHER EAST. HOWEVER...THE ISSUANCE OF A WARNING AND THE
EXPANSION OF THE CURRENT ADVISORY DID NOT SEEM FEASIBLE GIVEN LOW
CONFIDENCE AND HIGH UNCERTAINTY BEYOND THE CURRENT WINTER WEATHER
HEADLINES. WILL ALLOW DAY SHIFT TO REEVALUATE AND CONSIDER THESE
OPTIONS.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 408 AM CDT MON APR 8 2013
THE MAIN FORECAST PROBLEM EARLY IN THE EXTENDED PERIOD WILL BE
PRECIPITATION CHANCES ALONG THE NORTHERN PERIPHERY OF THE LARGE
SYSTEM OVER THE CENTRAL AND NORTHERN PLAINS...IN ADDITION TO
TEMPERATURES UNDER COLD HIGH PRESSURE TO THE NORTH OF THE SYSTEM. A
PROGRESSIVE WEST TO NORTHWEST UPPER FLOW WILL DEVELOP BY LATE IN THE
WORK WEEK AND THROUGH THE WEEKEND BRINGING PERIODIC CHANCES OF MIXED
PRECIPITATION.
TUESDAY AND WEDNESDAY SHOULD BE QUIET ACROSS ALL BUT THE FAR SOUTH.
COLD SURFACE HIGH PRESSURE OVER SOUTHERN CANADA INTO THE NORTH
DAKOTA SHOULD KEEP THE NORTH DRY. DETERMINISTIC MODELS KEEP THE
NORTHERN EDGE OF THE STRONG SYSTEM NEAR THE SOUTH DAKOTA BORDER. THE
GEM/ECMWF KEEP SOME LIGHT QPF ALONG THE SOUTHERN TIER COUNTIES WHILE
THE GFS KEEPS PRECIPITATION SOUTH OF THE STATE. LOWERED TEMPERATURES
A BIT FROM PREVIOUS FORECAST...WITH LESS SKY COVER...COLDER MID
LEVEL TEMPERATURES AND REMAINING SNOWPACK...THE FAR NORTHERN
COUNTIES SHOULD SEE SOME LOWER TEENS AND SINGLE DIGITS FOR OVERNIGHT
LOWS. FAVOR A EC/GEM SOLUTION AS FAR AS PRECIPITATION ON TUESDAY AND
WEDNESDAY...THUS WILL KEEP POPS ALONG THE SOUTH DAKOTA BORDER
THROUGH THE PERIOD. AT THIS TIME...WILL NOT BRING A SIGNIFICANT
AMOUNT OF QPF TO THE SOUTH...HOWEVER...THERE IS A VERY SHARP CUTOFF
ON THE NORTHERN EDGE OF THE DEFORMATION ZONE. A NORTHWARD SHIFT OF
ONLY A FEW MILES WOULD BRING ACCUMULATING SNOWS INTO THE SOUTHERN
TIER COUNTIES. WILL DEFINITELY NEED TO MONITOR THIS OVER THE NEXT
FEW MODEL RUNS.
THE ECMWF...WHICH HAS BEEN THE MOST CONSISTENT OF THE DETERMINISTIC
MODELS WITH THIS SYSTEM...HAS NOW SWITCHED THINGS UP BY KEEPING THE
UPPER LEVEL SYSTEM FARTHER NORTH ON THURSDAY...DUE TO STRONGER
DOWNSTREAM BLOCKING. THIS WOULD KEEP A CHANCE OF LIGHT SNOW OVER THE
SOUTHEAST CWA. FOR NOW WILL STICK WITH A BLEND OF MODELS WITH
PERSISTENCE...WHICH KEEPS THE SOUTHEAST DRY AND SEE IF THIS WAS JUST
AN ANOMALY FROM THE 00 UTC MONDAY ECMWF RUN.
THIS CHANGE IN THE ECMWF ALSO AFFECTS THE LATTER PORTIONS OF THE
EXTENDED PERIOD. THE SLOWER SOLUTION RESULTS IN UPSTREAM RIDGING AND
THE PROGRESSIVE FLOW OFF THE PACIFIC IS SHUNTED NORTH...YIELDING A
MAINLY DRY FORECAST LATE IN THE WORK WEEK AND INTO THE WEEKEND. THIS
FINALLY BREAKS DOWN BY LATE SATURDAY AND A SYSTEM EMANATING FROM THE
PACIFIC MOVES INTO THE AREA SATURDAY NIGHT AND SUNDAY. THE GFS/GEM
BRING THE PROGRESSIVE FLOW INTO THE AREA EARLIER. THE SYSTEM
FORECAST TO MOVE INTO THE CWA ON THURSDAY FROM PREVIOUS RUNS IS
WEAKER...AND HAVE TONED DOWN POPS A BIT FROM PREVIOUS FORECAST. THE
NEXT SYSTEM ENTERS A GOOD 12-18 HOURS PRIOR TO THE ECMWF. EITHER
SOLUTION WOULD BRING ANOTHER ROUND OF MIXED PRECIPITATION WITH SNOW
NORTH...RAIN SOUTH...AND A MIX IN THE MIDDLE. TEMPERATURES DO
MODERATE LATER IN THE PERIOD...FROM HIGHS IN THE 20S AND 30S ON
TUESDAY AND WEDNESDAY...TO THE 30S AND 40S THURSDAY THROUGH SUNDAY.
WHICH WILL STILL BE BELOW NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 408 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 06 UTC TAF PERIOD. LATEST
SATELLITE IMAGERY HAS SHOWN LIFR TO IFR CONDITIONS IN STRATUS AND
FOG. LIFR TO IFR CEILINGS ARE EXPECTED TO CONTINUE THROUGH
DAYBREAK...AND THEN IMPROVE TO IFR TO MARGINAL MVFR.
LOW PRESSURE ACROSS MONTANA WILL DEVELOP AND SNOW WITH SLEET AND
FREEZING RAIN WILL BEGIN TO IMPACT KDIK AFTER 09Z...SPREADING EAST
MONDAY MORNING IMPACTING OTHER TERMINALS. VISIBILITIES IN SNOW AND
BLOWING SNOW WILL LIKELY FALL TO IFR AND BELOW FOR KDIK-KBIS.
SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON FOR ALL BUT
KJMS- KDIK AND POSSIBLY KBIS WHICH MAY REMAIN MVFR-IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ017>020-031>034-040>044.
&&
$$
SHORT TERM...LTH
LONG TERM...TWH
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
107 AM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 107 AM CDT MON APR 8 2013
LATEST RADAR REFLECTIVITY AT 545Z SHOWS SOME LIGHT PRECIPITATION
STARTING TO DEVELOP ACROSS THE SOUTHWEST...WITH MORE WIDESPREAD
LIGHT TO MODERATE PRECIPITATION OVER EASTERN MONTANA EARLY THIS
MORNING. THE LATEST 04Z RAP HAS THE HEAVIER PRECIPITATION HOLDING
OFF UNTIL AFTER 08 TO 09Z. MEANWHILE ACROSS THEN NORTH...VERY
LIGHT RETURNS HAVE ALSO MANIFESTED...INDICATING SOME LIGHT SNOW
ALONG A COLD FRONT MOVING SOUTH FROM CANADA. SURFACE OBSERVATIONS
CONTINUE TO INDICATE THAT MOST OF THE SOUTHWEST REMAINS ABOVE
FREEZING...BUT ACROSS THE NORTH...TEMPERATURES HAVE RAPIDLY
COOLED. THIS TREND WILL CONTINUE AS COLDER AIR MOVES SOUTH.
OVERALL...DID NOT MAKE TOO MANY CHANGES TO ONGOING
FORECAST...OTHER THAN TO UPDATE FOR CURRENT OBS AND TRENDS.
THE MAIN FORECAST CHALLENGE WILL CONTINUE TO BE THE APPROACHING
SYSTEM AND WHETHER OR NOT ANY CHANGES TO ONGOING WINTER WEATHER
HEADLINES WILL BE NEEDED. WILL EVALUATE LATEST GFS AND WAIT FOR
THE 00Z ECWMF BEFORE MAKING ANY DECISIONS.
UPDATE ISSUED AT 1020 PM CDT SUN APR 7 2013
STORM SYSTEM SET TO IMPACT MONDAY MORNING/AFTERNOON WILL START TO
PRECIPITATE OVER MY FAR WEST AFTER MIDNIGHT...WITH THE HEAVIER
PRECIPITATION NOT TO ARRIVE UNTIL 09Z OR AFTER. AREA OF LIGHT SNOW
DEVELOPING ACROSS MY NORTH FROM CANADA WILL CONTINUE TO SLOWLY
MOVE SOUTH TO NEAR THE INTERSTATE 94 CORRIDOR OVERNIGHT ALONG A
SOUTHWARD ADVANCING COLD FRONT. OVERALL DID NOT MAKE MANY CHANGES
TO POPS FROM THE PREVIOUS UPDATED FORECAST. ADJUSTED TEMPERATURES
TO REFLECT LATEST OBS AND MODEL TRENDS...KEEPING THINGS WARM UNTIL
THE COLDER AIR MOVES IN FROM CANADA AFTER MIDNIGHT WITH EXTENSIVE
STRATUS IN PLACE.
OF NOTE TO THE MIDNIGHT SHIFT...THE 00Z NAM AND 18Z GFS HAVE COME
IN VERY WET WITH NEAR AN INCH OF QPF ALONG AND SOUTH OF THE
MISSOURI RIVER FOR STORM TOTALS OVERNIGHT THROUGH MONDAY
AFTERNOON. MUCH OF THIS LOOKS TO FALL AS SNOW. THE 12Z ECMWF WAS
ABOUT HALF AS WET. IF THE NAM/GFS VERIFY...WILL NEED TO UPGRADE
PARTS OF THE WINTER WEATHER ADVISORY TO A WARNING FOR HEAVY
SNOW...WITH AN INCH OF QPF RESULTING IN AT LEAST 10 INCHES OF
SNOW. WOULD ALSO HAVE TO CONSIDER EXPANDING THE AERIAL COVERAGE OF
THE WINTER WEATHER ADVISORY. WILL NEED TO SEE WHAT THE LATEST GFS
(00Z) COMES IN WITH...AND CHECK WITH THE WPC (WEATHER PREDICTION
CENTER) FOLKS.
&&
.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 412 PM CDT SUN APR 7 2013
FREEZING RAIN HAS ENDED NOW ACROSS THE JAMES RIVER VALLEY AS
TEMPERATURES HAVE WARMED ABOVE FREEZING. THE SNOW ACROSS THE NORTH
CENTRAL HAS ALSO ENDED. SO THERE IS A CLEAN SLATE FOR THE NEXT
WINTER SYSTEM WHICH IS FORECAST TO IMPACT MAINLY SOUTHWEST AND
SOUTH CENTRAL NORTH DAKOTA AFTER MIDNIGHT TONIGHT THROUGH MONDAY.
HAVE KEPT THE WINTER WEATHER ADVISORY FOR THIS AREA. ONCE AGAIN
THE LOWER TEMPERATURE PROFILE SUPPORTS A WINTRY MIX AT FIRST. AS
COLDER AIR IS DRAWN INTO THE SYSTEM DURING THE DAY MONDAY THE
PRECIPITATION WILL BECOME ALL SNOW...ALTHOUGH A WINTRY MIX IS
WILL STILL BE POSSIBLE SOUTH CENTRAL. SNOW AMOUNTS UP TO 5 INCHES
IS POSSIBLE FAR SOUTHWEST THROUGH WEST CENTRAL...WHERE CURRENTLY NO
SNOW COVER IS FOUND.
.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 412 PM CDT SUN APR 7 2013
THE MAIN FORECAST PROBLEMATIC TIME PERIOD IN THE EXTENDED PERIOD IS
TUESDAY THROUGH TUESDAY NIGHT...WHERE LIGHT SNOW ACCUMULATIONS MAY
OCCUR ACROSS FAR SOUTHWEST AND FAR SOUTH CENTRAL NORTH DAKOTA.
LEANED MORE TOWARD A GFS/ECMWF SOLUTION AS THE NAM WAS DEEMED AN
OUTLIER BRINGING SYSTEMS TOO FAR NORTH.
THE LONG TERM BEGINS MONDAY NIGHT WITH THE LARGE LONGWAVE TROUGH
OVER THE CENTRAL/SOUTHERN ROCKIES NEARLY CUTTING OFF FROM THE MAIN
BELT OF THE WESTERLIES...AND A SURFACE CANADIAN HIGH PRESSURE SYSTEM
MOVING SOUTHWARD ACROSS NORTH DAKOTA. LINGERING ENERGY FROM THE
LARGE SYSTEM TO THE SOUTH SHOULD AFFECT THE SOUTHERN TIER OF
COUNTIES MONDAY NIGHT IN THE FORM OF LIGHT SNOW. LOW TEMPERATURES
EXPECTED TO RANGE FROM 5 ABOVE IN THE NORTH TO THE TEENS SOUTH.
THE MODELS BRING THE LARGE LONGWAVE TROUGH EASTWARD INTO THE
CENTRAL/SOUTHERN PLAINS...WITH SOME ENERGY MOVING NORTHWARD FAR
ENOUGH TO BRING CHANCES OF SNOW ALONG THE SOUTHERN TIER ON TUESDAY.
COOL WITH HIGHS ONLY 25 TO 35.
BY TUESDAY NIGHT THE UPPER LEVEL TROUGH ELONGATES ENOUGH TO BRING A
SURGE OF ENERGY FROM THE TROUGH NORTHWARD INTO CENTRAL NORTH
DAKOTA...BUT BY THIS TIME THE ASSOCIATED SURFACE LOW IN THIS LARGE
SYSTEM IS WELL ESTABLISHED OVER MISSOURI AND THE MAIN PRECIPITATION
SHIELD AND BAROCLINIC ZONE IS TO THE SOUTH AND EAST OF OUR AREA.
LOWS TUESDAY NIGHT FROM 10 NORTHWEST TO 20 SOUTH CENTRAL.
THUS TUESDAY THROUGH TUESDAY NIGHT...A PERIOD OF CONTINUOUS LIGHT
SNOW CHANCES ACROSS THE SOUTHERN TIER OF COUNTIES MAY RESULT IN 1 TO
4 INCHES OF SNOWFALL POSSIBLE MAINLY FROM SLOPE/BOWMAN COUNTIES
EASTWARD TO LAMOURE/DICKEY COUNTIES...WITH UP TO AN INCH OF SNOW
POSSIBLE AS FAR NORTH AS INTERSTATE 94.
WEDNESDAY THROUGH NEXT WEEKEND...AS THE MONDAY/TUESDAY SYSTEM EXITS
TO THE EASTERN US...A BROAD UPPER LEVEL TROUGH DEVELOPS OVER WESTERN
NORTH AMERICA. THIS REGIME WILL KEEP TEMPERATURES BELOW AVERAGE FOR
THIS TIME OF YEAR...AND BRING SMALL CHANCES OF PRECIPITATION OFF AND
ON BUT AT THIS TIME DO NOT SEE ANY SIGNIFICANT PRECIPITATION IN THE
OFFING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 107 AM CDT MON APR 8 2013
MULTIPLE AVIATION HAZARDS AGAIN FOR THE 06 UTC TAF PERIOD. LATEST
SATELLITE IMAGERY HAS SHOWN LOWERING CEILINGS TO LIFR CONDITIONS
WITHIN STRATUS...WITH LIFR TO IFR CEILINGS EXPECTED TO CONTINUE
THROUGH DAYBREAK...AND THEN IMPROVE TO IFR TO MARGINAL MVFR.
LOW PRESSURE ACROSS MONTANA WILL DEVELOP AND SNOW WITH SLEET AND
FREEZING RAIN WILL BEGIN TO IMPACT KDIK AFTER 09Z...SPREADING EAST
MONDAY MORNING IMPACTING OTHER TERMINALS. VISIBILITIES IN SNOW AND
BLOWING SNOW WILL LIKELY FALL TO IFR AND BELOW FOR KDIK-KBIS.
SHOULD SEE IMPROVING CONDITIONS MONDAY AFTERNOON FOR ALL BUT
KJMS- KDIK AND POSSIBLY KBIS WHICH MAY REMAIN MVFR-IFR.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ TUESDAY
FOR NDZ017>020-031>034-040>044.
&&
$$
UPDATE...LTH
SHORT TERM...WAA
LONG TERM...JV
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1046 PM EDT TUE APR 9 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 WEDNESDAY 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 WEDNESDAY 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
LAKESHORE. A COLD FRONT WILL SLOWLY MOVE ACROSS THE AREA MONDAY INTO
TUESDAY AND WILL LIKELY BRING WIDESPREAD SHOWERS ACROSS THE AREA.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
WARM FRONT IS WEDGED UP CLOSE TO THE SOUTH SHORE OF LAKE ERIE THIS
EVENING WITH LITTLE MOVEMENT EXPECTED THROUGH THE NIGHT. MOST OF
THE SHOWER AND THUNDERSTORMS ACTIVITY IS EXPECTED TO REMAIN NORTH
OF THE FRONTAL BOUNDARY THIS EVENING. HOWEVER A COUPLE OF THE
SHOWERS MAY CLIP KCLE AND KERI LATE IN THE EVENING. WE WILL THEN
AWAIT THE ARRIVAL OF THE NEXT PIECE OF JET ENERGY THAT SHOULD
INCREASE THE LIFT ACROSS NW OHIO AFTER MIDNIGHT. THIS WILL SLOWLY
PROGRESS EASTWARD ACROSS THE REGION THROUGH WEDNESDAY MORNING. IN
THE WAKE OF THIS JET ENERGY THE FRONTAL BOUNDARY SHOULD WOBBLE
FURTHER INLAND WITH NORTHEAST WINDS FOR MUCH OF THE REGION. THE
ONLY EXCEPTION MAY BE KFDY AND KMFD WHERE SOUTHWEST WINDS MAY
BECOME GUSTY BY THE AFTERNOON.
AT THIS POINT IT APPEARS MOST LOCATIONS WILL REMAIN VFR UNTIL THE
SHOWERS SPREAD ACROSS THE REGION AFTER 06Z. MVFR CONDITIONS SHOULD
THEN ACCOMPANY THE SHOWERS THROUGH AT LEAST MID MORNING BEFORE
IMPROVING. THERE MAY BE SOME LOCALIZED IFR CONDITIONS IN THE
HEAVIEST SHOWERS/THUNDER.
.OUTLOOK...NON-VFR DEVELOPING THURSDAY AND CONTINUING INTO FRIDAY.
&&
.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...MULLEN
MARINE...ADAMS
HYDROLOGY...
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
703 PM EDT MON APR 8 2013
.SYNOPSIS...
A NEARLY STATIONARY FRONTAL BOUNDARY WILL LINGER OVER NORTHERN
OHIO THROUGH MID WEEK...KEEPING MILD AND UNSETTLED WEATHER IN THE
FORECAST. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED
THURSDAY WHEN A STRONG COLD FRONT IS FORECAST TO CROSS THE AREA.
COOLER AIR WILL ARRIVE FRIDAY AFTER THE FRONT MOVES EAST.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW PRESSURE IS CENTERED OVER LAKE MICHIGAN...WITH A WARM FRONT
EXTENDING TO NORTHEAST OHIO. ILN AREA IS IN THE WARM SECTOR...WITH
MOSTLY CLOUDY SKIES AND A BREEZY AND MILD SOUTHERLY FLOW.
THE LOW WILL MOVE EAST TONIGHT ACROSS THE STATE OF MICHIGAN INTO
SOUTHERN ONTARIO. IN THE PROCESS...A BOUNDARY IS FORECAST TO SET
UP IN COUNTIES NORTH OF DAYTON. RAP MODEL LOOKS TO HAVE THE BEST
REPRESENTATION OF THE BOUNDARY...WITH THE LOWER RESOLUTION GFS AND
ECMWF ALSO SUGGESTING SUCH A SOLUTION. THE NAM APPEARS TO BE THE
OUTLIER IN SHOWING A BOUNDARY DEVELOPING FARTHER SOUTH OVER
KENTUCKY. AN AREA OF INSTABILITY MOVING FROM INDIANA MAY COME
INTO PLAY WHEN THE BOUNDARY DEVELOPS THIS EVENING.
WENT WITH A CHANCE OF A SHOWERS WITH A SLIGHT CHANCE FOR
THUNDERSTORMS THIS EVENING IN NORTHERN COUNTIES AFFECTED BY THE
BOUNDARY...DIMINISHING TO A SLIGHT CHANCE OF SHOWERS LATER
TONIGHT.
LOWS WILL BE ABOVE NORMAL IN THE MID 50S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
FOR TUESDAY THROUGH WEDNESDAY...THE BOUNDARY WILL STAY POSITIONED
OVER NORTHERN OHIO. THIS WILL KEEP THE ILN IN A WARM SOUTHERLY
FLOW. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP IN THE
UNSTABLE AIRMASS MAINLY NORTH OF I-70...CLOSER TO THE FRONTAL
BOUNDARY AND ITS ASSOCIATED SHORT WAVE ENERGY AND DEEPER MOISTURE.
MAIN ELEMENT OF INTEREST MAY BE HIGH TEMPERATURES REACHING WELL INTO
THE 70S...WITH LOWER 80S CREEPING INTO SOME SOUTHERN LOCATIONS ON
WEDNESDAY. NORMAL HIGHS RANGE FROM THE UPPER 50S TO LOWER 60S.
FOR WEDNESDAY NIGHT...LOW PRESSURE FORMING TO THE WEST WILL PUSH A
STRONG COLD FRONT TOWARD THE AREA. SHOWERS AND THUNDERSTORMS WILL
BECOME LIKELY OVER WESTERN LOCATIONS LATE WEDNESDAY NIGHT. CANNOT
RULE OUT SEVERE THUNDERSTORMS IN A HIGH SHEAR LOW INSTABILITY
ENVIRONMENT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
POTENT SHORT WAVE WILL LIFT ACROSS THE REGION AT THE BEGINNING OF
THE PERIOD. THIS WILL PUSH A STRONG COLD FRONT THROUGH THE REGION
THURSDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AHEAD
OF THIS BOUNDARY. SHEAR WILL BE SUFFICIENT FOR SEVERE THUNDERSTORMS
BUT INSTABILITY IS IN QUESTION.
ACTIVITY WILL MOVE EAST OF THE REGION THURSDAY NIGHT. BUT THERE IS
THE POTENTIAL FOR ADDITIONAL SHOWERS ON FRIDAY WITH A SECONDARY
TROUGH SWINGING THROUGH. HIGH PRESSURE WILL BUILD IN FOR THE
WEEKEND. TEMPERATURES WILL DROP BACK BELOW NORMAL AT THE END OF THE
WEEK BUT THEN START TO MODERATE. MODELS SHOWING TIMING DISCREPANCIES
WITH A COLD FRONT THAT COULD POTENTIALLY IMPACT MONDAY. SEEMS MORE
LIKELY THAT THE FRONT WILL STAY FAR ENOUGH WEST THROUGH THE END OF
THE PERIOD THAT FURTHER RAIN CHANCES WILL BE QUITE LIMITED.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
A STATIONARY FRONTAL BOUNDARY ACROSS THE SOUTHERN GREAT LAKES THIS
EVENING WILL REMAIN QUASI-STATIONARY THROUGH THE TAF PERIOD.
IN THE SHORT TERM...FAVORABLE AXIS OF INSTABILITY IN ASSOCIATION
WITH LOW LEVEL CONVERGENCE WAS LOCATED FROM NORTHERN
ILLINOIS...NORTHERN INDIANA...INTO NORTHWEST OHIO. MOSAIC RADAR
HAS BEEN SHOWING SHOWER DEVELOPMENT HERE. HIGH RESOLUTION MODELS
SUGGEST THAT THESE SHOWERS...AND PERHAPS A THUNDERSTORM...WILL
DRIFT EAST/SOUTHEAST TOWARD THE TAF SITES OF KKDAY...KCMH...KLCK
THROUGH 04Z. THEREAFTER...LOW LEVEL FORCING WITH THIS PCPN
WEAKENS. AS A RESULT...WILL PLACE A TEMPO PERIOD OF LIGHT SHOWERS
AT THE AFOREMENTIONED TAF SITES WITH ONLY A VCSH POSSIBLE ELSEWHERE.
FOR THE OVERNIGHT PERIOD INTO THE FIRST PART OF TUESDAY...ANOTHER
EMBEDDED MID LEVEL WEATHER DISTURBANCE AND ASSOCIATED 850 MB JET
MAY GENERATE ANOTHER AREA OF SHOWERS AND THUNDERSTORMS TO OUR
WEST/NORTHWEST ACROSS NORTHERN/CENTRAL ILLINOIS AND INDIANA LATE.
IT IS UNCLEAR HOW MUCH OF THIS ACTIVITY MAY DRIFT INTO NORTHWEST
AND WEST CENTRAL OHIO TOWARD MORNING. DUE TO LOW CONFIDENCE...HAVE
KEPT A VCSH AT KDAY. BY MID MORNING INTO MID AFTERNOON...POTENTIAL
PCPN NEAR KDAY WILL SHIFT EAST/NORTHEAST...AND WITH DAYTIME
MIXING...TAF SITES SHOULD BE FIRMLY IN THE WARM SECTOR WITH LITTLE
CHANCES OF SHOWERS AND THUNDERSTORMS EXPECTED WITH A NOTICEABLE
MID LEVEL CAPPING INVERSION.
WINDS WILL BECOMING VARIABLE OVERNIGHT NEAR KDAY...KCMH..KLCK WITH
LIGHT SOUTHERLY ELSEWHERE. DAYTIME MIXING ON TUESDAY WILL INCREASE
WINDS FROM THE SOUTH AROUND 15 KNOTS WITH GUSTS OF 25 KNOTS
POSSIBLE DURING THE PEAK HEATING HOURS OF THE DAY.
OUTLOOK...THUNDERSTORMS POSSIBLE WEDNESDAY INTO WEDNESDAY NIGHT.
THUNDERSTORMS LIKELY THURSDAY INTO THURSDAY EVENING. MVFR
CEILINGS POSSIBLE THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...HICKMAN
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
435 PM EDT MON APR 8 2013
.SYNOPSIS...
A NEARLY STATIONARY FRONTAL BOUNDARY WILL LINGER OVER NORTHERN
OHIO THROUGH MID WEEK...KEEPING MILD AND UNSETTLED WEATHER IN THE
FORECAST. WIDESPREAD SHOWERS AND THUNDERSTORMS ARE EXPECTED
THURSDAY WHEN A STRONG COLD FRONT IS FORECAST TO CROSS THE AREA.
COOLER AIR WILL ARRIVE FRIDAY AFTER THE FRONT MOVES EAST.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
LOW PRESSURE IS CENTERED OVER LAKE MICHIGAN...WITH A WARM FRONT
EXTENDING TO NORTHEAST OHIO. ILN AREA IS IN THE WARM SECTOR...WITH
MOSTLY CLOUDY SKIES AND A BREEZY AND MILD SOUTHERLY FLOW.
THE LOW WILL MOVE EAST TONIGHT ACROSS THE STATE OF MICHIGAN INTO
SOUTHERN ONTARIO. IN THE PROCESS...A BOUNDARY IS FORECAST TO SET
UP IN COUNTIES NORTH OF DAYTON. RAP MODEL LOOKS TO HAVE THE BEST
REPRESENTATION OF THE BOUNDARY...WITH THE LOWER RESOLUTION GFS AND
ECMWF ALSO SUGGESTING SUCH A SOLUTION. THE NAM APPEARS TO BE THE
OUTLIER IN SHOWING A BOUNDARY DEVELOPING FARTHER SOUTH OVER
KENTUCKY. AN AREA OF INSTABILITY MOVING FROM INDIANA MAY COME
INTO PLAY WHEN THE BOUNDARY DEVELOPS THIS EVENING.
WENT WITH A CHANCE OF A SHOWERS WITH A SLIGHT CHANCE FOR
THUNDERSTORMS THIS EVENING IN NORTHERN COUNTIES AFFECTED BY THE
BOUNDARY...DIMINISHING TO A SLIGHT CHANCE OF SHOWERS LATER
TONIGHT.
LOWS WILL BE ABOVE NORMAL IN THE MID 50S.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
FOR TUESDAY THROUGH WEDNESDAY...THE BOUNDARY WILL STAY POSITIONED
OVER NORTHERN OHIO. THIS WILL KEEP THE ILN IN A WARM SOUTHERLY
FLOW. SCATTERED SHOWERS AND THUNDERSTORMS MAY DEVELOP IN THE
UNSTABLE AIRMASS MAINLY NORTH OF I-70...CLOSER TO THE FRONTAL
BOUNDARY AND ITS ASSOCIATED SHORT WAVE ENERGY AND DEEPER MOISTURE.
MAIN ELEMENT OF INTEREST MAY BE HIGH TEMPERATURES REACHING WELL INTO
THE 70S...WITH LOWER 80S CREEPING INTO SOME SOUTHERN LOCATIONS ON
WEDNESDAY. NORMAL HIGHS RANGE FROM THE UPPER 50S TO LOWER 60S.
FOR WEDNESDAY NIGHT...LOW PRESSURE FORMING TO THE WEST WILL PUSH A
STRONG COLD FRONT TOWARD THE AREA. SHOWERS AND THUNDERSTORMS WILL
BECOME LIKELY OVER WESTERN LOCATIONS LATE WEDNESDAY NIGHT. CANNOT
RULE OUT SEVERE THUNDERSTORMS IN A HIGH SHEAR LOW INSTABILITY
ENVIRONMENT.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
POTENT SHORT WAVE WILL LIFT ACROSS THE REGION AT THE BEGINNING OF
THE PERIOD. THIS WILL PUSH A STRONG COLD FRONT THROUGH THE REGION
THURSDAY NIGHT. SHOWERS AND THUNDERSTORMS WILL BE WIDESPREAD AHEAD
OF THIS BOUNDARY. SHEAR WILL BE SUFFICIENT FOR SEVERE THUNDERSTORMS
BUT INSTABILITY IS IN QUESTION.
ACTIVITY WILL MOVE EAST OF THE REGION THURSDAY NIGHT. BUT THERE IS
THE POTENTIAL FOR ADDITIONAL SHOWERS ON FRIDAY WITH A SECONDARY
TROUGH SWINGING THROUGH. HIGH PRESSURE WILL BUILD IN FOR THE
WEEKEND. TEMPERATURES WILL DROP BACK BELOW NORMAL AT THE END OF THE
WEEK BUT THEN START TO MODERATE. MODELS SHOWING TIMING DISCREPANCIES
WITH A COLD FRONT THAT COULD POTENTIALLY IMPACT MONDAY. SEEMS MORE
LIKELY THAT THE FRONT WILL STAY FAR ENOUGH WEST THROUGH THE END OF
THE PERIOD THAT FURTHER RAIN CHANCES WILL BE QUITE LIMITED.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
PREVAILING VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
HOWEVER...WITH WEAK INSTABILITY EXPECTED TO DEVELOP OVER THE
REGION BY LATE AFTERNOON...SOME POP-UP SHOWERS (AND MAYBE
THUNDERSTORMS) WILL OCCUR. A VCSH HAS BEEN INCLUDED AT ALL THE TAF
SITES TO ACCOUNT FOR THIS POSSIBILITY. THE BEST CHANCE FOR
THUNDERSTORMS WILL BE NORTH OF THE TAF SITES...THOUGH NOT TOO FAR
NORTH AND WEST OF DAYTON.
OVERNIGHT...SOME OF THE COMPUTER MODELS INDICATE THAT SCATTERED
SHOWERS MAY PERSIST. HOWEVER...THIS PROBABILITY SEEMS TOO LOW TO
INCLUDE IN THE TAFS THIS FAR OUT. THERE MAY BE ANOTHER CHANCE OF
SHOWERS AND POSSIBLY STORMS BY MID MORNING TUESDAY...WITH DAYTON
AGAIN BEING THE MORE LIKELY TAF SITE TO BE AFFECTED.
WHILE CLOUD BASES WILL BE AT VARIOUS LEVELS THROUGH THE TAF
PERIOD...THEY ARE EXPECTED TO REMAIN IN THE VFR CATEGORY. IF A
SHOWER PASSES OVER A TAF SITE...DEGRADED CONDITIONS COULD BE
EXPECTED.
OUTLOOK...THUNDERSTORMS ARE POSSIBLE TUESDAY AND WEDNESDAY.
THUNDERSTORMS ARE LIKELY ON THURSDAY. MVFR CEILINGS ARE POSSIBLE
THURSDAY NIGHT INTO FRIDAY.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...CONIGLIO
NEAR TERM...CONIGLIO
SHORT TERM...CONIGLIO
LONG TERM...
AVIATION...HATZOS
AREA FORECAST DISCUSSION
NWS NORMAN OK
725 PM CDT TUE APR 9 2013
.UPDATE...
SHORT TERM UPDATE...
&&
.DISCUSSION...
THROUGH 00Z...THE COLD FRONT CONTINUES TO MOVE VERY QUICKLY
SOUTHEASTWARD ACROSS THE REGION. THROUGH 7 PM...SURFACE ANALYSIS
PLACES THE FRONT FROM WAURIKA TO CHANDLER TO FORAKER...AND INTO
SOUTHEASTERN KANSAS. BEHIND THE FRONT...TWO SEPARATE BANDS OF
THUNDERSTORMS HAVE DEVELOPED ALONG THE EASTERN EDGE OF THE 500MB
LOW...DISPLACED TO THE EAST OF THE 300MB JET MAX OF 100 TO 120KTS
ACROSS THE PANHANDLES. WV IMAGERY DEPICTS TWO SUBTLE WAVES RIDING
THE UPPER LEVEL FLOW...POSSIBLY PROVIDING A SOURCE OF LIFT ACROSS
THE NORTH TEXAS PLAINS AND THE NORTHEASTERN PORTION OF THE
PANHANDLES.
THE FIRST LINE...ACROSS NORTHWESTERN OKLAHOMA...CURRENTLY EXTENDS
FROM THE EASTERN TEXAS PANHANDLE THROUGH CENTRAL KANSAS. FORECAST
SOUNDINGS FROM THE RECENT RUN OF THE RAP ACROSS NORTHWESTERN
OKLAHOMA SHOW A DEFINED CAPPING INVERSION/WARM NOSE FROM NEAR
850MB TO 700 MB. STORMS REMAIN ELEVATED...WITH THE BEST LIFT IN
THE 800 TO 850MB LEVEL...WITH DECENT MOISTURE AVAILABLE TO AID IN
UPDRAFT DEVELOPMENT. GIVEN THE FRONTAL PASSAGE EARLIER THIS
AFTERNOON...SURFACE TEMPS CONTINUED TO DROP ACROSS NORTHWESTERN
OKLAHOMA TODAY. WITH TEMPS IN THE 30S THIS EVENING...AND
DEVELOPING THUNDERSTORMS...THIS HAS RESULTED IN QUITE AN
INTERESTING EVENT...WITH SMALL HAIL/SLEET/GRAUPLE OCCURRING WITH
THE WEAKER THUNDERSTORMS...AND HAIL TO THE SIZE OF
QUARTERS...NEARING GOLF BALLS WITH THE STRONGEST. SOME LOCATIONS
HAVE HAD A NICE COVERING OF FZRA AND SLEET ACROSS THE REGION.
WITH THE SECOND LINE...THE PRIMARY CONVECTION ACROSS WESTERN NORTH
TEXAS APPEARS TO BE FOCUSED ALONG THE LEADING EDGE OF THE
FRONT. EARLIER UPDRAFTS THAT DEVELOPED QUICKLY SHIFTED INTO THE
COLD SECTOR...LOSING VERTICAL DEVELOPMENT AND WEAKENING AS THE
FRONT UNDERCUT. WITH THE FRONT CONTINUING TO MARCH EAST/SOUTHEASTWARD
THROUGH 00Z...RECENT UPDRAFTS HAVE PERSISTED LONGER...AS THE SPC
MESOANALYSIS PAGE SHOW CURRENT UPDRAFTS SOUTH OF THE RED RIVER
MOVING INTO A MORE FAVORABLE ENVIRONMENT...WITH MLCAPE VALUES IN
THE 500 TO 1500 RANGE. THE ONLY CONCERN IS THE SPEED OF THE
FRONT...WHICH WILL CONTINUE TO THREATEN NEW UPDRAFTS..
HOWEVER...CONVECTION THAT HAS BEEN ABLE TO PERSIST HAS RESULTED IN
NICKEL TO QUARTER SIZE HAIL.
OVERALL...SCATTERED CONVECTION WILL CONTINUE TO PERSIST THROUGH
THE EVENING. LARGE HAIL AND STRONG WINDS...BOTH FROM THE FRONT AND
STORMS...WILL REMAIN THE PRIMARY THREATS. STILL EXPECT WINTRY
PRECIP TO SPREAD SOUTHEASTWARD THROUGH SUNRISE...WITH THE HIGHEST
IMPACTS NORTH AND WEST OF THE I-44 CORRIDOR.
JTK
&&
.PREV DISCUSSION... /ISSUED 624 PM CDT TUE APR 9 2013/
DISCUSSION...
00Z AVIATION DISCUSSION FOLLOWS...
AVIATION...
DIVERSE WEATHER WOULD BE AN UNDERSTATEMENT FOR THIS TAF PERIOD.
THROUGH 10/00Z...SCATTERED THUNDERSTORMS HAVE DEVELOPED ACROSS FAR
WESTERN OKLAHOMA...AS WELL AS WESTERN NORTH TEXAS AND SOUTHWESTERN
OKLAHOMA. THIS ACTIVITY QUICKLY DEVELOPED BEHIND THE PRIMARY
FRONTAL BAND...WHICH CONTINUES TO CRUISE SOUTHEASTWARD ACROSS THE
REGION. REPORTS OF FZRAPL AS WELL AS TSRAPL WILL BE POSSIBLE EARLY
IN THE PERIOD AT KGAG AND KWWR...THROUGH 10/06Z THIS EVENING.
ELSEWHERE...FROM KPNC TO KOKC TO KHBR WILL LIKELY SEE INCREASED
PRECIP ACTIVITY THROUGH MIDNIGHT...WITH -TSRA EARLY TRANSITIONING
TO -FZRA...-FZRAPL...AND -SN THROUGH SUNRISE. FROM KLAW TO
KSPS...-TSRA CHANCES THIS EVENING WILL LIKELY TRANSITION TO
WINTRY PRECIP THROUGH THE EARLY MORNING HOURS.
OVERALL...WINTRY PRECIP WILL TAPER OFF TO THE EAST THROUGH THE
MID TO LATE MORNING...EXITING CENTRAL OKLAHOMA AND WESTERN NORTH
TEXAS THROUGH NOON.
JTK
PREV DISCUSSION... /ISSUED 119 PM CDT TUE APR 9 2013/
DISCUSSION...
MAIN FOCUS WAS ON THE NEXT 48 HOURS OR SO WITH SEVERE WEATHER AND
WINTER WEATHER IMPACTS.
THE COLD FRONT WHICH HAS MOVED ACROSS PARTS OF WESTERN OK WILL
CONTINUE TO MOVE ACROSS THE REGION THROUGH TONIGHT. TEMPERATURES
BEHIND THE FRONT ARE FALLING RAPIDLY INTO MAINLY THE 40S AND 50S...
WITH THE NORTHWEST WINDS BEHIND THE FRONT BECOMING BREEZY/WINDY.
MEANWHILE... UPPER LOW OVER THE FOUR CORNERS WILL CONTINUE TO MOVE
EAST THROUGH WEDNESDAY. THUNDERSTORMS WILL DEVELOP ALONG AND MAYBE
AHEAD OF THE FRONT THIS AFTERNOON/EVENING. THESE STORMS WILL BE
SEVERE PRODUCING LARGE HAIL AND STRONG WINDS. ANY STORMS THAT ARE
ABLE TO STAY DISCRETE /SUPERCELLS/ COULD ALSO PRODUCE TORNADOES.
SHOWERS/STORMS WILL ALSO DEVELOP BEHIND THE FRONT. SOME OF THE RAIN
COULD BE HEAVY... ESPECIALLY IF TRAINING OF STORMS OCCURS... WHICH
MAY CAUSE SOME LOCALIZED FLOODING.
AS THE COLD AIR MOVES INTO THE AREA... THE PRECIP IS EXPECTED TO
CHANGE TO FREEZING RAIN/SLEET AND MAYBE EVEN SOME SNOW TONIGHT INTO
WEDNESDAY. THIS WINTER WX COULD AFFECT ROADWAYS BUT THE BIGGER
IMPACT MAY BE ACCUMULATIONS OF ICE ON POWER LINES AND TREES...
ESPECIALLY WITH BREEZY/WINDY CONDITIONS EXPECTED OVERNIGHT. ISSUED A
WINTER WX ADVISORY EARLIER TODAY TO COVER THIS. PRECIPITATION IS
EXPECTED TO END FROM WEST TO EAST WEDNESDAY.
FREEZING TEMPERATURES WILL BE POSSIBLE ACROSS PARTS OF THE AREA
AGAIN WEDNESDAY NIGHT AND THURSDAY NIGHT. TEMPERATURES ARE EXPECTED
TO WARM THIS WEEKEND.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 30 45 28 55 / 80 60 10 0
HOBART OK 29 46 23 58 / 90 20 0 0
WICHITA FALLS TX 32 51 32 60 / 90 40 0 0
GAGE OK 23 42 25 58 / 70 20 0 0
PONCA CITY OK 31 45 26 52 / 90 60 10 0
DURANT OK 42 53 34 59 / 90 90 10 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM CDT
WEDNESDAY FOR OKZ006>008-011>013-015>025-027-033>038.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT WEDNESDAY FOR OKZ004-005-
009-010-014.
TX...WINTER WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO 1 PM CDT
WEDNESDAY FOR TXZ083>085-087.
&&
$$
03/02/04
AREA FORECAST DISCUSSION
NWS NORMAN OK
1222 PM CDT MON APR 8 2013
.AVIATION...
18Z TAFS... MVFR CEILINGS EXPECTED AGAIN TONIGHT ACROSS THE AREA.
MODELS SUGGEST SOME DRIZZLE TO DEVELOP TUESDAY MORNING BUT WILL
HOLD OFF PUTTING IN THE TAFS FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 1044 AM CDT MON APR 8 2013/
UPDATE...
INCREASED HIGH TEMPERATURES A FEW DEGREES ACROSS SOUTHWEST
OKLAHOMA AND FAR WESTERN NORTH TEXAS THIS AFTERNOON. TWEAKED LATE
AFTERNOON/EVENING STORM CHANCES TODAY AS WELL AS SKY COVER
AND WINDS.
DISCUSSION...
THE CHALLENGE OF THE DAY IS DETERMINING WHETHER OR NOT A FEW
STORMS WILL DEVELOP ACROSS WESTERN OKLAHOMA AND WESTERN NORTH
TEXAS LATE THIS AFTERNOON AND EVENING.
BASED ON SURROUNDING RAOBS THIS MORNING...A RATHER STRONG CAP
IS IN PLACE ACROSS THE REGION. TO BREAK IT...CONVECTIVE TEMPERATURES
MUST REACH THE 84 TO 93 DEGREE RANGE...WHICH SEEMS TO ONLY BE
POSSIBLE ACROSS FAR WESTERN OKLAHOMA AND FAR WESTERN NORTH TEXAS
ACCORDING TO LATEST MODELS. SINCE THESE AREAS ARE SUNNY AT THIS
MOMENT AND BASED ON LATEST HRRR RUNS...INCREASED HIGHS IN THESE
AREAS WITH HIGHS IN THE LOWER TO PERHAPS MID 90S WEST OF A SAYRE
TO ALTUS TO SEYMOUR LINE.
FOR NOW...KEPT A 20 PERCENT CHANCE FOR STORMS MAINLY NEAR A
WOODWARD TO KNOX CITY LINE BETWEEN 4 AND 7 PM CDT...AND NEAR
AN ALVA TO WEATHERFORD TO VERNON LINE 7 PM CDT TO 1 AM CDT. IF
STORMS DEVELOP...WHICH REMAINS A BIG IF...THEY WOULD BE HIGH
BASED AT FIRST WITH DAMAGING WIND AS THE MAIN HAZARD...BUT COULD
INTENSIFY QUICKLY AS THEY MOVE EAST INTO DEEPER MOISTURE AND
BETTER INSTABILITY...SUGGESTING A LARGE HAIL AND PERHAPS A
TORNADO THREAT. CONFIDENCE OF ANY STORMS DEVELOPING THIS
AFTERNOON AND EVENING REMAINS LOW AS NOT SURE IF THE CAP CAN
BE OVERCOME...ESPECIALLY WITHOUT A MID/UPPER LEVEL TRIGGER TO
PROVIDE LIFT.
FOR THE OKLAHOMA CITY METRO AREA...THUNDERSTORMS ARE NOT
EXPECTED THROUGH MIDDAY TUESDAY.
PRODUCTS HAVE BEEN UPDATED.
MBS
FIRE WEATHER...
WILL BE CLOSE TO CRITICAL FIRE WEATHER CONDITIONS BETWEEN 2 AND 9
PM CDT TODAY ACROSS FAR WESTERN NORTH TEXAS AND FAR WESTERN
OKLAHOMA...MAINLY ALONG AND WEST OF A GAGE TO SEYMOUR LINE. DUE
TO MARGINAL WINDS AND SOME UNCERTAINTY WITH HUMIDITY LEVELS...HELD
OFF WITH A RED FLAG WARNING...BUT WILL CLOSELY MONITOR.
MBS
PREV DISCUSSION... /ISSUED 647 AM CDT MON APR 8 2013/
AVIATION...
08/12Z TAFS...PRIMARILY MVFR CIGS WITH INCREASING SOUTHERLY WIND
THROUGH THE DAY INTO TONIGHT. MVFR CONDITIONS FOR A FEW HOURS
EARLY THIS MORNING ACROSS SOUTHWEST OKLAHOMA AND KSPS BUT EXPECT
MOST OF CIGS TO SHIFT JUST EAST OF THOSE TERMINALS AFTER 15Z AND
RETURN AFTER 02Z. WEST-CENTRAL/NW OKLAHOMA TERMINALS WILL HAVE TO
DEAL WITH MVFR/IFR CONDITIONS EARLY IN FORECAST PERIOD NEAR AND
JUST NORTH OF WARM FRONT. FRONT WILL MAKE SLOW PROGRESS NORTHWARD
THIS MORNING WITH IMPROVING CONDITIONS AFTER 15-18Z. WILL NOT
INCLUDE TSRA IN ANY TERMINAL DUE TO VERY ISOLATED /IF ANY/ NATURE
LATER TODAY.
PREV DISCUSSION... /ISSUED 437 AM CDT MON APR 8 2013/
DISCUSSION...
STRONG CAP EXPECTED TO KEEP THUNDERSTORM CHANCES VERY LOW AGAIN
TODAY WITH ANY ISOLATED DEVELOPMENT NEAR DRYLINE/WARM FRONT OVER
FAR WEST/NORTHWEST OKLAHOMA. DEWPOINTS WILL BE SLIGHTLY HIGHER
TODAY AND LATEST MODELS INDICATE MORE IN THE WAY OF LOW-LEVEL
CONVERGENCE...BUT CAP WILL REMAIN QUITE STRONG. SCATTERED STORMS
THAT FIRED AROUND THE TULSA AREA FORMED ON NOSE OF LOW LEVEL JET
AND 800-700MB TIGHT BAROCLINIC ZONE. THIS ACTIVITY AND OTHER
ASSOCIATED WITH SAID TEMP GRADIENT SHOULD STAY NORTH AND EAST OF
CWA THIS MORNING.
LOW POPS WILL BE SEEN OVER A SMALL AREA OF WESTERN/NORTHERN
OKLAHOMA LATE TODAY INTO THIS EVENING WITH QUICK INCREASE IN POPS
TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING. ALTHOUGH WE CANNOT
RULE OUT A FEW STORMS IN WARM SECTOR NEAR/EAST OF DRYLINE
TUESDAY...PRIMARY FOCUS FOR WIDESPREAD THUNDERSTORMS WILL BE
STRONG COLD FRONT THAT WILL MOVE INTO NORTHWEST OKLAHOMA LATE
TUESDAY AFTERNOON AND MOVE QUICKLY SOUTHEAST OVER REGION. ALTHOUGH
SIGNIFICANT WEATHER WILL BE SEEN WITH ANY STORM THAT HAPPENS TO
DEVELOP AHEAD OF FRONT...PRIMARY IMPACTS FROM SEVERE WEATHER WILL
BE WIND/HAIL ASSOCIATED WITH SQUALL LINE. POTENTIAL FOR SEVERE
WEATHER EXPECTED TO DECREASE WITH ANY POST-FRONTAL STORMS LATE
TUESDAY NIGHT AND WEDNESDAY. MUCH COLDER AIR WILL FILTER IN BEHIND
FRONT...AND GIVEN PROGD GRADIENT AND COLD ADVECTION...WIND
ADVISORY MAY BE NEEDED TUESDAY NIGHT/EARLY WEDNESDAY MORNING.
SPEAKING OF COLD AIR...WE WILL MENTION SOME RAIN/SNOW AND SNOW
AREAS ACROSS PORTIONS OF NORTHERN AND WESTERN OKLAHOMA TUESDAY
NIGHT AND EARLY WEDNESDAY MORNING. DESPITE SOME AGGRESSIVE SNOW
OUTPUT FROM MODELS...PRECIP WILL BE ENDING AND INTRUSION OF DRY
AIR EXPECTED TO PRECLUDE ANY SIGNIFICANT ACCUMS. FREEZE LIKELY
ACROSS AT LEAST NORTHWEST THIRD OR SO OF OKLAHOMA WEDNESDAY
MORNING AND POSSIBLY OVER A MUCH LARGER AREA THURSDAY MORNING.
GIVEN THAT WE HAVE PASSED THE CLIMO FOR FREEZES OVER CENTRAL AND
SOUTHERN OKLAHOMA/NORTHERN TEXAS...FREEZE WARNINGS MAY BE
WARRANTED.
REINFORCING SHOTS OF COOLER AIR EXPECTED THROUGH FRIDAY WITH
WARMUP INCREASING OVER WEEKEND. MODELS SOMEWHAT INCONSISTENT WITH
PRECIP POTENTIAL LATE FRIDAY AND SATURDAY WITH NORTHWEST FLOW
SYSTEM...BUT WITH RUN TO RUN CONSISTENCY LESS THAN DESIRED DID NOT
INTRO POPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 77 64 75 36 / 0 10 20 70
HOBART OK 87 62 77 32 / 20 20 30 50
WICHITA FALLS TX 84 63 81 38 / 0 10 20 60
GAGE OK 84 61 71 25 / 20 10 20 30
PONCA CITY OK 75 63 74 36 / 0 10 30 70
DURANT OK 74 64 77 52 / 10 10 10 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25/25
AREA FORECAST DISCUSSION...CORRECTED
NWS NORMAN OK
1044 AM CDT MON APR 8 2013
.UPDATE...
INCREASED HIGH TEMPERATURES A FEW DEGREES ACROSS SOUTHWEST
OKLAHOMA AND FAR WESTERN NORTH TEXAS THIS AFTERNOON. TWEAKED LATE
AFTERNOON/EVENING STORM CHANCES TODAY AS WELL AS SKY COVER
AND WINDS.
&&
.DISCUSSION...
THE CHALLENGE OF THE DAY IS DETERMINING WHETHER OR NOT A FEW
STORMS WILL DEVELOP ACROSS WESTERN OKLAHOMA AND WESTERN NORTH
TEXAS LATE THIS AFTERNOON AND EVENING.
BASED ON SURROUNDING RAOBS THIS MORNING...A RATHER STRONG CAP
IS IN PLACE ACROSS THE REGION. TO BREAK IT...CONVECTIVE TEMPERATURES
MUST REACH THE 84 TO 93 DEGREE RANGE...WHICH SEEMS TO ONLY BE
POSSIBLE ACROSS FAR WESTERN OKLAHOMA AND FAR WESTERN NORTH TEXAS
ACCORDING TO LATEST MODELS. SINCE THESE AREAS ARE SUNNY AT THIS
MOMENT AND BASED ON LATEST HRRR RUNS...INCREASED HIGHS IN THESE
AREAS WITH HIGHS IN THE LOWER TO PERHAPS MID 90S WEST OF A SAYRE
TO ALTUS TO SEYMOUR LINE.
FOR NOW...KEPT A 20 PERCENT CHANCE FOR STORMS MAINLY NEAR A
WOODWARD TO KNOX CITY LINE BETWEEN 4 AND 7 PM CDT...AND NEAR
AN ALVA TO WEATHERFORD TO VERNON LINE 7 PM CDT TO 1 AM CDT. IF
STORMS DEVELOP...WHICH REMAINS A BIG IF...THEY WOULD BE HIGH
BASED AT FIRST WITH DAMAGING WIND AS THE MAIN HAZARD...BUT COULD
INTENSIFY QUICKLY AS THEY MOVE EAST INTO DEEPER MOISTURE AND
BETTER INSTABILITY...SUGGESTING A LARGE HAIL AND PERHAPS A
TORNADO THREAT. CONFIDENCE OF ANY STORMS DEVELOPING THIS
AFTERNOON AND EVENING REMAINS LOW AS NOT SURE IF THE CAP CAN
BE OVERCOME...ESPECIALLY WITHOUT A MID/UPPER LEVEL TRIGGER TO
PROVIDE LIFT.
FOR THE OKLAHOMA CITY METRO AREA...THUNDERSTORMS ARE NOT
EXPECTED THROUGH MIDDAY TUESDAY.
PRODUCTS HAVE BEEN UPDATED.
MBS
&&
.FIRE WEATHER...
WILL BE CLOSE TO CRITICAL FIRE WEATHER CONDITIONS BETWEEN 2 AND 9
PM CDT TODAY ACROSS FAR WESTERN NORTH TEXAS AND FAR WESTERN
OKLAHOMA...MAINLY ALONG AND WEST OF A GAGE TO SEYMOUR LINE. DUE
TO MARGINAL WINDS AND SOME UNCERTAINTY WITH HUMIDITY LEVELS...HELD
OFF WITH A RED FLAG WARNING...BUT WILL CLOSELY MONITOR.
MBS
&&
.PREV DISCUSSION... /ISSUED 647 AM CDT MON APR 8 2013/
AVIATION...
08/12Z TAFS...PRIMARILY MVFR CIGS WITH INCREASING SOUTHERLY WIND
THROUGH THE DAY INTO TONIGHT. MVFR CONDITIONS FOR A FEW HOURS
EARLY THIS MORNING ACROSS SOUTHWEST OKLAHOMA AND KSPS BUT EXPECT
MOST OF CIGS TO SHIFT JUST EAST OF THOSE TERMINALS AFTER 15Z AND
RETURN AFTER 02Z. WEST-CENTRAL/NW OKLAHOMA TERMINALS WILL HAVE TO
DEAL WITH MVFR/IFR CONDITIONS EARLY IN FORECAST PERIOD NEAR AND
JUST NORTH OF WARM FRONT. FRONT WILL MAKE SLOW PROGRESS NORTHWARD
THIS MORNING WITH IMPROVING CONDITIONS AFTER 15-18Z. WILL NOT
INCLUDE TSRA IN ANY TERMINAL DUE TO VERY ISOLATED /IF ANY/ NATURE
LATER TODAY.
PREV DISCUSSION... /ISSUED 437 AM CDT MON APR 8 2013/
DISCUSSION...
STRONG CAP EXPECTED TO KEEP THUNDERSTORM CHANCES VERY LOW AGAIN
TODAY WITH ANY ISOLATED DEVELOPMENT NEAR DRYLINE/WARM FRONT OVER
FAR WEST/NORTHWEST OKLAHOMA. DEWPOINTS WILL BE SLIGHTLY HIGHER
TODAY AND LATEST MODELS INDICATE MORE IN THE WAY OF LOW-LEVEL
CONVERGENCE...BUT CAP WILL REMAIN QUITE STRONG. SCATTERED STORMS
THAT FIRED AROUND THE TULSA AREA FORMED ON NOSE OF LOW LEVEL JET
AND 800-700MB TIGHT BAROCLINIC ZONE. THIS ACTIVITY AND OTHER
ASSOCIATED WITH SAID TEMP GRADIENT SHOULD STAY NORTH AND EAST OF
CWA THIS MORNING.
LOW POPS WILL BE SEEN OVER A SMALL AREA OF WESTERN/NORTHERN
OKLAHOMA LATE TODAY INTO THIS EVENING WITH QUICK INCREASE IN POPS
TUESDAY AFTERNOON THROUGH WEDNESDAY MORNING. ALTHOUGH WE CANNOT
RULE OUT A FEW STORMS IN WARM SECTOR NEAR/EAST OF DRYLINE
TUESDAY...PRIMARY FOCUS FOR WIDESPREAD THUNDERSTORMS WILL BE
STRONG COLD FRONT THAT WILL MOVE INTO NORTHWEST OKLAHOMA LATE
TUESDAY AFTERNOON AND MOVE QUICKLY SOUTHEAST OVER REGION. ALTHOUGH
SIGNIFICANT WEATHER WILL BE SEEN WITH ANY STORM THAT HAPPENS TO
DEVELOP AHEAD OF FRONT...PRIMARY IMPACTS FROM SEVERE WEATHER WILL
BE WIND/HAIL ASSOCIATED WITH SQUALL LINE. POTENTIAL FOR SEVERE
WEATHER EXPECTED TO DECREASE WITH ANY POST-FRONTAL STORMS LATE
TUESDAY NIGHT AND WEDNESDAY. MUCH COLDER AIR WILL FILTER IN BEHIND
FRONT...AND GIVEN PROGD GRADIENT AND COLD ADVECTION...WIND
ADVISORY MAY BE NEEDED TUESDAY NIGHT/EARLY WEDNESDAY MORNING.
SPEAKING OF COLD AIR...WE WILL MENTION SOME RAIN/SNOW AND SNOW
AREAS ACROSS PORTIONS OF NORTHERN AND WESTERN OKLAHOMA TUESDAY
NIGHT AND EARLY WEDNESDAY MORNING. DESPITE SOME AGGRESSIVE SNOW
OUTPUT FROM MODELS...PRECIP WILL BE ENDING AND INTRUSION OF DRY
AIR EXPECTED TO PRECLUDE ANY SIGNIFICANT ACCUMS. FREEZE LIKELY
ACROSS AT LEAST NORTHWEST THIRD OR SO OF OKLAHOMA WEDNESDAY
MORNING AND POSSIBLY OVER A MUCH LARGER AREA THURSDAY MORNING.
GIVEN THAT WE HAVE PASSED THE CLIMO FOR FREEZES OVER CENTRAL AND
SOUTHERN OKLAHOMA/NORTHERN TEXAS...FREEZE WARNINGS MAY BE
WARRANTED.
REINFORCING SHOTS OF COOLER AIR EXPECTED THROUGH FRIDAY WITH
WARMUP INCREASING OVER WEEKEND. MODELS SOMEWHAT INCONSISTENT WITH
PRECIP POTENTIAL LATE FRIDAY AND SATURDAY WITH NORTHWEST FLOW
SYSTEM...BUT WITH RUN TO RUN CONSISTENCY LESS THAN DESIRED DID NOT
INTRO POPS.
&&
.PRELIMINARY POINT TEMPS/POPS...
OKLAHOMA CITY OK 77 64 75 36 / 0 10 20 70
HOBART OK 87 62 77 32 / 20 20 30 50
WICHITA FALLS TX 84 63 81 38 / 0 10 20 60
GAGE OK 84 61 71 25 / 20 10 20 30
PONCA CITY OK 75 63 74 36 / 0 10 30 70
DURANT OK 74 64 77 52 / 10 10 10 60
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
TX...NONE.
&&
$$
17/25
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1132 AM EDT MON APR 8 2013
.SYNOPSIS...
A WARM FRONT IS LIFTING NORTHWARD ACROSS CENTRAL PA. SCATTERED
SHOWERS AND ISOLATED AFTERNOON THUNDERSTORM WILL BE
POSSIBLE...MAINLY ACROSS THE NORTHWESTERN MOUNTAINS. ABOVE NORMAL
TEMPERATURES ARE EXPECTED TO PREVAIL FOR MUCH OF THE COMING WEEK.
SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE...MAINLY OVER
NORTHERN PENNSYLVANIA INTO THURSDAY. A COLD FRONT WILL PASS
THROUGH LATE IN THE WEEK WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS. THE STORM WILL USHER IN COOLER AND DRIER CONDITIONS
FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 8 PM THIS EVENING/...
THE FRONT IS MOST LIKELY LIFTING THROUGH THE WESTERN MOUNTAINS
RIGHT NOW AND DEWPOINTS ARE MOVING UPWARD. SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE THIS AFTERNOON WHILE THE WARM FRONT
PUSHES ACROSS. WINDS ARE INCREASING THROUGH THE MID-LAYERS THROUGH
THE AFTERNOON AND LAST THIS EVENING AS A LL JET OF ABOUT 50KTS
NOSES INTO THE NWRN MTS. WILL HOLD OFF ON A MENTION OF GUSTY WINDS
OR HAIL AT THIS POINT...BUT NEW INFO FROM RUC/RAP AND HRRR WILL
AID WITH THIS DECISION LATER TODAY. THE COVERAGE MAY ALSO BE
RATHER SPARSE. WILL HOLD POPS IN THE HIGH CHC/LOW LIKELY RANGE
UNTIL SUNSET.
&&
.SHORT TERM /8 PM THIS EVENING THROUGH 6 PM TUESDAY/...
TSRA STILL POSSIBLE IN THE EVENING AND MID LEVEL JET REMAINS AT
ABOUT 50KTS ALONG THE NY BORDER.
EVENING CONVECTION MAY CONTINUE THROUGH MID TO LATE EVENING AS
ADDITIONAL SHORTWAVES FLATTEN THE SHORTWAVE RIDGE ACROSS THE
REGION AND DEEP LAYER MOISTURE OF 1"+ IS REPLACED BY <0.75" PW BY
06Z. BOUNDARY LAYER CONVERGENCE IS RATHER ROBUST WITH 40+ KT 850
MB WINDS PROPAGATING EASTWARD ACROSS THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ THIS EVENING. ACTIVITY SHOULD DWINDLE QUICKLY AFTER
MIDNIGHT WITH THE ARRIVAL OF DRIER AIR ALOFT AND DECREASING
BOUNDARY LAYER CONVERGENCE BETWEEN 06Z AND 12Z TUE. OVERNIGHT MINS
WILL BE GENERALLY MILD...RANGING FROM THE UPPER 40S NORTHWEST TO
THE MID 50S SOUTHEAST.
TUESDAY WILL BE SIMILAR TO MONDAY WITH A MOISTURE BOUNDARY DRAPED
ACROSS THE SOUTH CENTRAL MOUNTAINS...WHERE PW WILL RANGE FROM 0.5"
ACROSS THE CENTRAL MOUNTAINS TO ABOUT 0.85 ALONG THE PA/MD BORDER
TO START THE DAY. ANOTHER NORTHWARD SURGE OF MOISTURE WILL TAKE
PLACE AS YET ANOTHER SFC TROF LIFTS NEWD THROUGH THE CENTRAL AND
EASTERN GREAT LAKES...TOUCHING OFF ANOTHER ROUND OF SHOWERS AND
LOCAL THUNDERSTORMS TUESDAY AFTERNOON. IT WILL BE MILDER STILL
WITH HIGHS RANGING FROM THE MID 60S NORTH TO THE MID TO UPPER 70S
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
WARM CONDITIONS FOR MUCH OF THE PERIOD TUE EVE INTO THU...AS MUCH
OF CENTRAL PA WILL BE IN THE WARM AIR. NOW LOOKS LIKE MUCH OF THE
RAIN WILL BE MUCH FURTHER NORTH THIS WEEK.
IT WILL BE INTERESTING TO SEE HOW WARM WE GET BY MID WEEK...GIVEN
THE CHANGE IN THE UPPER LVL PATTERN. WILL SEE HOW THIS PLAYS OUT
ESPECIALLY GIVEN THE RECENT HIGH LATITUDE BLOCKING AND COLD SPELL.
TEMPS COULD PUSH UPPER 80S SOUTHERN PA BY WED...GIVEN 850 MB
TEMPS.
&&
.AVIATION /15Z MONDAY THROUGH FRIDAY/...
WARM FRONT LIFTING NORTHWARD ACROSS THE REGION TODAY WILL ALLOW
SCT TSRA TO FORM...BUT THEY WILL NOT BE WIDESPREAD ENOUGH TO
MENTION IN THE TAFS JUST YET. WILL MENTION SHRA FOR MOST
SITES...BUT MDT/LNS SHOULD NOT HAVE ANY SHRA. CIGS/VISBYS WILL
REMAIN VFR...EXCEPT IN THE FEW SHRA THAT DO HAPPEN TO PASS RIGHT
OVER THE AIRFIELDS. KBFD IS MOST-LIKELY TO SEE A REDUCTION TO
MVFR...MAINLY BETWEEN 21Z AND 03Z. BUT FORCING REMAIN WELL TO THE
NORTH OF THE AREA THIS AFTN/TONIGHT. WINDS DO GET STRONG AT FL050
WITH UP TO 50KTS ALONG THE NY BORDER. THIS COULD CREATE SOME GUSTS
IN THE STORMS. BUT...AGAIN...THESE SHOULD BE ISOLD/SCT IN
COVERAGE.
.OUTLOOK...
TUE...EARLY AM LOW CIGS POSS W MTNS. ISOLD TSRA IMPACTS POSS NORTH.
WED...EARLY AM LOW CIGS POSS NW MTNS. ISOLD TSRA IMPACTS POSS NORTH.
THU...CHC OF PM TSRA IMPACTS.
FRI...AM RAIN/LOW CIGS POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO/DEVOIR
LONG TERM...MARTIN/STEINBUGL
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
803 AM EDT MON APR 8 2013
.SYNOPSIS...
A STALLED SURFACE FRONT ALONG THE TURNPIKE THIS MORNING WILL LIFT
NORTHWARD AS A WARM FRONT ACROSS CENTRAL PA TODAY. SCATTERED
SHOWERS AND ISOLATED AFTERNOON THUNDERSTORM WILL BE POSSIBLE.
ABOVE NORMAL TEMPERATURES ARE EXPECTED TO PREVAIL FOR MUCH OF THE
COMING WEEK. SCATTERED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE...MAINLY OVER NORTHERN PENNSYLVANIA INTO THURSDAY. A
COLD FRONT WILL PASS THROUGH LATE IN THE WEEK AND USHER IN COOLER
AND DRIER CONDITIONS FOR NEXT WEEKEND.
&&
.NEAR TERM /UNTIL 7 PM THIS EVENING/...
--SHRA OVER THE TURNPIKE PLACE THE FRONT ALOFT JUST ABOUT THERE
THIS MORNING. THE FRONT SHOULD START TO LIFT NORTHWARD OVER THE
WESTERN COUNTIES. SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE THIS AFTERNOON WHILE THE WARM FRONT PUSHES ACROSS. WINDS
ARE INCREASING THROUGH THE MID-LAYERS THROUGH THE AFTERNOON AND
LAST THIS EVENING AS A LL JET OF ABOUT 50KTS NOSES INTO THE NWRN
MTS. WILL HOLD OFF ON A MENTION OF GUSTY WINDS OR HAIL AT THIS
POINT...BUT NEW INFO FROM RUC/RAP AND HRRR WILL AID WITH THIS
DECISION LATER TODAY. THE COVERAGE MAY ALSO BE RATHER SPARSE. WILL
HOLD POPS IN THE HIGH CHC/LOW LIKELY RANGE UNTIL SUNSET.
&&
.SHORT TERM /7 PM THIS EVENING THROUGH 6 PM TUESDAY/...
TSRA STILL POSSIBLE IN THE EVENING AND MID LEVEL JET REMAINS AT
ABOUT 50KTS ALONG THE NY BORDER.
EVENING CONVECTION MAY CONTINUE THROUGH MID TO LATE EVENING AS
ADDITIONAL SHORTWAVES FLATTEN THE SHORTWAVE RIDGE ACROSS THE
REGION AND DEEP LAYER MOISTURE OF 1"+ IS REPLACED BY <0.75" PW BY
06Z. BOUNDARY LAYER CONVERGENCE IS RATHER ROBUST WITH 40+ KT 850
MB WINDS PROPAGATING EASTWARD ACROSS THE SOUTH CENTRAL MOUNTAINS
AND LOWER SUSQ THIS EVENING. ACTIVITY SHOULD DWINDLE QUICKLY AFTER
MIDNIGHT WITH THE ARRIVAL OF DRIER AIR ALOFT AND DECREASING
BOUNDARY LAYER CONVERGENCE BETWEEN 06Z AND 12Z TUE. OVERNIGHT MINS
WILL BE GENERALLY MILD...RANGING FROM THE UPPER 40S NORTHWEST TO
THE MID 50S SOUTHEAST.
TUESDAY WILL BE SIMILAR TO MONDAY WITH A MOISTURE BOUNDARY DRAPED
ACROSS THE SOUTH CENTRAL MOUNTAINS...WHERE PW WILL RANGE FROM 0.5"
ACROSS THE CENTRAL MOUNTAINS TO ABOUT 0.85 ALONG THE PA/MD BORDER
TO START THE DAY. ANOTHER NORTHWARD SURGE OF MOISTURE WILL TAKE
PLACE AS YET ANOTHER SFC TROF LIFTS NEWD THROUGH THE CENTRAL AND
EASTERN GREAT LAKES...TOUCHING OFF ANOTHER ROUND OF SHOWERS AND
LOCAL THUNDERSTORMS TUESDAY AFTERNOON. IT WILL BE MILDER STILL
WITH HIGHS RANGING FROM THE MID 60S NORTH TO THE MID TO UPPER 70S
SOUTHEAST.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
WARM CONDITIONS FOR MUCH OF THE PERIOD TUE EVE INTO THU...AS MUCH
OF CENTRAL PA WILL BE IN THE WARM AIR. NOW LOOKS LIKE MUCH OF THE
RAIN WILL BE MUCH FURTHER NORTH THIS WEEK.
IT WILL BE INTERESTING TO SEE HOW WARM WE GET BY MID WEEK...GIVEN
THE CHANGE IN THE UPPER LVL PATTERN. WILL SEE HOW THIS PLAYS OUT
ESPECIALLY GIVEN THE RECENT HIGH LATITUDE BLOCKING AND COLD SPELL.
TEMPS COULD PUSH UPPER 80S SOUTHERN PA BY WED...GIVEN 850 MB
TEMPS.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
SHOWERS HAVE CEASED AS ANY INSTABILITY HAS FADED OVERNIGHT INTO
TOMORROW.
THE BIGGEST AVIATION CONCERN IN THE NEAR TERM WILL BE THE
POSSIBILITY OF SOME LATE NIGHT FOG ACROSS SOUTHERN PA. MDL DATA
SHOWING A TONGUE OF RELATIVELY MOIST AIR IN VICINITY OF DYING COLD
FRONT LAYING OUT ACROSS SOUTHERN PA LATE TONIGHT. THIS
MOISTURE...COMBINED WITH DIMINISHING WINDS...COULD SET THE STAGE
FOR PATCHY RADIATION FOG ARND DAWN ACROSS SOUTHERN PA...ESP IN
THOSE FEW SPOTS THAT RECEIVE RAINFALL THIS EVENING. CONFIDENCE NOT
HIGH ENOUGH TO MENTION IN TAFS YET...BUT WILL HAVE TO MONITOR
OVERNIGHT.
GUSTY SW WINDS AHEAD OF THE CDFRNT EARLY THIS EVENING WILL WEAKEN
AS THE DYING FRONT WASHES OUT ACROSS SOUTHERN PA LATER THIS
EVENING.
ANY EARLY FOG SHOULD LIFT SHORTLY AFTER SUNRISE MONDAY. FOCUS
WILL THEN SHIFT TOWARD THE LIKELIHOOD OF SCT AFTN CONVECTION
ASSOCIATED WITH FRONTAL BOUNDARY LIFTING BACK NORTH ACROSS THE
REGION AS A WARM FRONT. AN AFTN SHRA/TSRA COULD BRIEFLY LOWER
VSBYS...DESPITE WIDESPREAD VFR CONDS.
.OUTLOOK...
TUE...EARLY AM LOW CIGS POSS W MTNS. ISOLD TSRA IMPACTS POSS NORTH.
WED...EARLY AM LOW CIGS POSS NW MTNS. ISOLD TSRA IMPACTS POSS NORTH.
THU...CHC OF PM TSRA IMPACTS.
FRI...AM RAIN/LOW CIGS POSS.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR
NEAR TERM...DANGELO
SHORT TERM...DEVOIR
LONG TERM...MARTIN/STEINBUGL
AVIATION...FITZGERALD/CERU
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
AREA FORECAST DISCUSSION
NWS SPOKANE WA
1114 AM PDT Mon Apr 8 2013
.SYNOPSIS...
Cool and showery weather will occur through today...with
further snow accumulations likely for the Cascade passes. The
next break in the active weather pattern will be on Tuesday but
active...showery and breezy weather will return on Wednesday. A
progressive weather regime with more showery storm systems are
expected later in the week through next weekend.
&&
.DISCUSSION...
Rest of Today...Yesterdays low pressure system remains fixed over
the Inland NW this morning per the latest visible satellite
picture...but the isallobaric analysis shows it is filling by
nearly a millibar per hour. Part of this is due to the low filling
and another portion is due to the influx of modified arctic air
spilling southwest down the Purcell Trench. The models are having
a tough time determining how far west this arctic intrusion will
spread. By 18z...NE winds are expected to overtake the northern
Palouse...Spokane Area...and eastern Columbia Basin. Once this air
arrives...dewpoints should fall and make the chances for
measurable precipitation quite small. Pops have been lowered
through the afternoon for these locations...however we won`t get
rid of them entirely. The best chances for showers this afternoon
will occur over NE and NC Washington where light showers were
persisting. Better instability is located over SE Washington and
NC Idaho per the RUC and HRRR...and this is where we would expect
to see the bulk of the convection occur this afternoon along the
remnants of the inverted surface trough axis. Model soundings over
the Blue Mountains and Lewiston area suggest convection maybe just
about deep enough to spawn an isolated thunderstorm...but its
quite borderline...so will leave it out of the forecast for now.
Much of the convection will begin to taper off overnight as
shortwave ridging begins to build in from the west. fx
&&
.AVIATION...
18Z TAFs: Weak surface low will keep unstable conditions over much
of the Inland NW again today so showers can be
expected to become more numerous...especially for PUW and LWS
where the instability is greatest. There will also be a threat of
GEG SFF and COE...however increasing E-NE flow will begin to
entrain drier air southwestward which should begin to lessen the
chances for showers and gradually raise the MVFR cigs. What time
the cigs climb above MVFR conditions is not a high confidence
forecast element...however conditional climatology suggests
sometime between 20-22z. The shower threat will decrease rapidly
overnight as ridging builds in from the west. This should bring
VFR conditions to all sites tonight through 18z Tue. Suspect there
could be some patchy fog forming overnight in the valleys of NE
and NC WA...but this should avoid all forecast sites. fx
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 48 34 53 39 58 38 / 20 10 0 10 60 60
Coeur d`Alene 46 30 54 36 57 37 / 30 10 0 10 60 60
Pullman 47 33 54 39 59 37 / 30 20 0 10 70 70
Lewiston 53 37 58 42 65 42 / 30 10 0 10 20 50
Colville 51 31 58 37 60 36 / 40 10 10 20 60 20
Sandpoint 45 31 51 35 54 36 / 50 20 0 10 70 70
Kellogg 44 28 50 35 52 36 / 60 20 0 20 70 70
Moses Lake 54 34 61 42 65 39 / 10 0 0 0 20 10
Wenatchee 54 39 59 43 61 41 / 10 0 0 0 20 10
Omak 52 34 60 39 62 37 / 20 0 0 10 20 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
626 PM CDT TUE APR 9 2013
.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 359 PM CDT TUE APR 9 2013
VERY ACTIVE/DIVERSE WEATHER IN STORE FOR THE NEXT COUPLE OF DAYS.
QUITE AN ACTIVE WEATHER DAY ALREADY WITH MODERATE TO HEAVY RAINFALL
ALONG WITH THUNDERSTORMS THIS MORNING AND SOME HAIL. CURRENTLY IN A
LULL WITH THE MID-LEVEL SHORTWAVE THAT CAUSED THE FIRST WAVE OF
RAIN/THUNDERSTORMS NOW OVER FAR EASTERN WI.
WATER VAPOR IMAGERY THIS AFTERNOON HAS A DEEP/CLOSED LOW OVER THE
4-CORNERS AREA WITH A STRONG MOISTURE FETCH FROM THE GULF NORTHWARD
INTO THE AREA. AT THE SURFACE...CYCLOGENESIS TAKING PLACE OVER THE
SOUTHERN PLAINS WITH A STRONG WARM FRONT EXTENDING THROUGH EASTERN
KS-AND THEN NORTHEAST THROUGH SOUTHEAST IA-NORTHERN IL-NORTHERN IN.
RADAR MOSAIC HAS ONGOING RAIN/THUNDERSTORMS ACROSS MAINLY EASTERN
WI WITH LIGHTER RAIN/DRIZZLE ACROSS OUR FORECAST AREA. ANOTHER BATCH
OF THUNDERSTORMS WAS ORGANIZING ACROSS EASTERN NEB AHEAD OF ANOTHER
MID-LEVEL SHORTWAVE EJECTING NORTHEAST OUT OF THE MAIN LOW OVER THE
4-CORNERS AREA. OTHERWISE...A FAIRLY RAW DAY IN PLACE ACROSS THE
FORECAST AREA WITH TEMPERATURES IN THE MID 30S TO LOWER 40S WITH
NORTHEAST WINDS IN THE 10-20 MPH RANGES EAST OF THE MISSISSIPPI
RIVER AND IN THE 15 TO 30 MPH RANGE IN THE MORE OPEN AREAS OF
NORTHEAST IA/SOUTHEAST MN.
LOOK FOR THE LOW OVER THE SOUTHERN PLAINS TO MOVE SLOWLY NORTHEAST
INTO MO WEDNESDAY. INCREASING FRONTOGENESIS IN THE 850-500MB LAYER
ALONG WITH INCREASING 850 MB MOISTURE TRANSPORT AHEAD OF THE
LOW/WARM FRONT WILL BRING ANOTHER ROUND OF RAIN/THUNDERSTORMS INTO
THE AREA. THERMAL PROFILES SUGGEST AREAS ALONG AND NORTH OF A LINE
FROM NEILLSVILLE/BLACK RIVER FALL/MONDOVI/ROCHESTER WILL LIKELY SEE
A WINTRY MIX OF MAINLY SLEET AND SNOW. UP TO AN INCH OF SNOW/SLEET
WILL BE POSSIBLE ACROSS THIS AREA FROM AFTER MIDNIGHT THROUGH
SUNRISE. SOME FREEZING RAIN IS ALSO POSSIBLE...BUT DUE TO WARM
GROUND...GLAZING EXPECTED TO BE MINOR AND LIMITED TO
ELEVATED/EXPOSED SURFACES SUCH AS RAILINGS/TREE BRANCHES/POWER WIRES.
FOR WEDNESDAY...THE LOW WILL CONTINUE TO LIFT NORTHEAST INTO WEST
CENTRAL IL WITH FETCH OF MOISTURE ROTATING INTO THE AREA.
MEANWHILE...A FETCH OF COLDER AIR IN NORTHEAST FLOW WILL BE
FILTERING IN FROM CANADA. THIS IS EXPECTED TO CONTINUE PRODUCING A
MIX OF SLEET/RAIN/SNOW MAINLY ACROSS PORTIONS OF SOUTHEAST MN INTO
NORTH CENTRAL WI. ELEVATED CAPE WILL ALSO CONTINUE THE THREAT FOR
EMBEDDED THUNDERSTORMS.
COLDER AIR WILL CONTINUE FILTERING INTO THE AREA WEDNESDAY NIGHT
INTO THURSDAY AS THE SURFACE LOW PULLS INTO NORTHERN IL.
ALSO...DYNAMIC COOLING WILL BE TAKING PLACE THROUGH THE COLUMN AS
THE MID/UPPER LEVEL LOW MAKES ITS WAY TOWARD THE AREA FROM THE
CENTRAL PLAINS. THIS WILL WILL PROVIDE FOR A FURTHER TRANSITION TO A
WINTRY MIX ACROSS MUCH OF THE AREA. THERE IS SOME QUESTION ON HOW
MUCH ICE WILL BE PRESENT IN THE COLUMN FOR SNOW PRODUCTION. RIGHT
NOW IT APPEARS THAT THERE WILL BE A LOSS OF ICE WHICH WOULD FAVOR A
GOOD AMOUNT OF LIQUID/FREEZING TYPE PRECIPITATION. WILL HAVE TO
WATCH THIS CLOSELY WITH THE NEXT MODEL RUN FOR FURTHER DETAIL IN
WHERE SNOW/SLEET VERSUS FREEZING RAIN WILL SET UP.
FOR NOW...WILL LEAVE CURRENT HEADLINES ALONE WITH A FLOOD WATCH
VALID THROUGH THURSDAY...AND A WINTER WEATHER ADVISORY FOR PORTIONS
OF SOUTHEAST MN INTO NORTH CENTRAL WI. AS MUCH A 1-3 INCHES OF RAIN
CAN BE EXPECTED FROM TODAY THROUGH THURSDAY...WITH THE HEAVIEST
RAINFALL OCCURRING SOUTH OF I-90. THE POTENTIAL FOR 3 TO AS MUCH AS 6
INCHES OF SNOW/SLEET COULD OCCUR FROM LATER TONIGHT THROUGH
THURSDAY//WITH THE MAJORITY FALLING WEDNESDAY NIGHT INTO THURSDAY//
IN THE WINTER WEATHER ADVISORY AREA. WILL HAVE TO MONITOR THE
POTENTIAL FOR ICE ACCUMULATION WEDNESDAY NIGHT INTO THURSDAY FOR
POTENTIAL THE POSSIBILITY OF UPGRADING TO A WARNING. MAY ALSO HAVE
TO ASSESS TO SEE IF ANOTHER TIER OF COUNTIES TO THE SOUTH OF THE
CURRENT ADVISORY WILL BE NEEDED AS WELL AND THERE IS SOME INDICATION
THAT THERE MAY BE SOME GLAZING THERE AS WELL ALONG WITH SOME MINOR
ACCUMULATING SNOW.
.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 359 PM CDT TUE APR 9 2013
FOR THURSDAY NIGHT...WILL SEE THE SURFACE LOW PULL INTO THE GREAT
LAKES REGION WHILE THE UPPER LOW ROTATES THROUGH THE AREA. APPEARS
DYNAMIC COOLING WILL BE ENOUGH TO TRANSITION PRECIPITATION TO ALL
SNOW THURSDAY NIGHT WITH SOME MINOR ACCUMULATIONS POSSIBLE...MAINLY
ALONG AND NORTHEAST OF I-94.
SURFACE HIGH PRESSURE WILL BUILD OVER THE UPPER MISSISSIPPI RIVER
VALLEY FRIDAY NIGHT AND REMAIN OVER THE REGION THROUGH SATURDAY. AN
UNSEASONABLY COOL AIRMASS WILL REMAIN IN PLACE OVER THE UPPER
MIDWEST FRIDAY NIGHT THROUGH SATURDAY WITH GEFS 850 MB STANDARDIZED
TEMPERATURE ANOMALIES OF NEGATIVE 1.5...WITH HIGHS ON FRIDAY ONLY
IN THE 30S. HIGHS WARM SLIGHTLY ON SATURDAY AND ARE EXPECTED TO
RANGE FROM THE UPPER 30S OVER NORTH CENTRAL WISCONSIN TO THE MID 40S
ACROSS NORTHEAST IOWA. ANOTHER SYSTEM LOOKS TO IMPACT THE REGION
SATURDAY NIGHT INTO SUNDAY. A VIGOROUS SHORTWAVE IS EXPECTED TO MOVE
ACROSS THE NORTHERN PLAINS DURING THIS TIME FRAME. SURFACE LOW
PRESSURE WILL DEEPEN OVER WESTERN MINNESOTA/EASTERN DAKOTAS WITH A
WARM FRONT LIFTING NORTH ACROSS THE UPPER MISSISSIPPI RIVER VALLEY.
PLAN ON PRECIPITATION OVERSPREADING THE AREA SATURDAY NIGHT. IT
APPEARS TEMPERATURES WILL BE COLD ENOUGH TO SUPPORT SNOW SATURDAY
NIGHT WITH A SWITCH OVER TO RAIN LATE IN THE NIGHT AS THE WARM FRONT
LIFTS NORTH AND WARMER AIR MOVES INTO THE REGION. THIS SYSTEM HAS
THE POTENTIAL TO BRING ANOTHER 1/4 TO 1/2 INCH OF RAINFALL TO THE
AREA WITH LOCALLY HIGHER AMOUNTS POSSIBLE IN EMBEDDED CONVECTION.
DESPITE THE RAINFALL...A RETURN TO MORE SEASONABLE TEMPERATURES ARE
IN STORE FOR PORTIONS OF THE AREA ON SUNDAY WITH HIGHS CLIMBING INTO
THE MID TO UPPER 50S ACROSS NORTHEAST IOWA INTO FAR SOUTHWEST
WISCONSIN. TEMPERATURES LOOK TO REMAIN ON THE COOL SIDE NORTH OF THE
I-90 CORRIDOR WITH HIGHS IN THE MID 40S TO LOWER 50S. A WEAK COLD
FRONT SLIDES THROUGH THE REGION LATE SUNDAY INTO MONDAY AS THE LOW
LIFTS NORTHEAST INTO ONTARIO. ZONAL FLOW SETS UP IN THE WAKE OF THE
LOW LATE MONDAY INTO TUESDAY AS ANOTHER TROUGH DEVELOPS OVER THE
SOUTHWEST CONUS. AN ACTIVE PATTERN WILL REMAIN ACROSS THE REGION
TUESDAY INTO WEDNESDAY AS THE TROUGH OVER THE SOUTHWEST CONUS EDGES
EAST WITH SHORTWAVE IMPULSES EJECTING NORTHEAST INTO THE REGION.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 625 PM CDT TUE APR 9 2013
VERY MESSY PERIOD AHEAD FOR THE TAF SITES. INITIAL ROUND OF RAIN
HAS MOVED OFF TO THE EAST LEAVING BEHIND IFR/MVFR CEILINGS AND
VISIBILITY WITH SOME LIGHT DRIZZLE AND FOG. THE NEXT ROUND OF RAIN
IS EXPECTED TO BE TIED TO THE SHORT WAVE TROUGH LIFTING NORTHEAST OUT
OF KANSAS LATE THIS AFTERNOON. THIS WAVE IS EXPECTED TO MOVE
ACROSS THE AREA DURING THE OVERNIGHT HOURS PUSHING ANOTHER ROUND
OF RAIN ACROSS. LOOKING AT THE 09.12Z HI-RES ARW AND NMM ALONG
WITH THE 09.19Z HRRR...THERE SEEMS TO BE PRETTY GOOD CONSENSUS
THAT THIS RAIN WILL START TO IMPACT THE TAF SITES AROUND 06Z WITH
BOTH VISIBILITY AND CEILINGS GOING BACK DOWN TO IFR. PREVIOUS
FORECASTS HAD INCLUDED A MENTION OF SOME THUNDER BUT CONFIDENCE ON
THIS OCCURRING IS PRETTY LOW. CURRENT MUCAPE IS BELOW 100 J/KG
NORTH OF THE IOWA/MINNESOTA BORDER AND THE 09.18Z NAM DOES NOT
SHOW THE ELEVATED CAPE GETTING ANY FARTHER NORTH THAN THIS THROUGH
THE NIGHT. OPTED TO LEAVE THE THUNDER MENTION IN THOUGH AS THE
LIFT IS EXPECTED TO BE PRETTY STRONG AHEAD OF THE WAVE AND THIS
COULD BE ENOUGH TO GENERATE A RUMBLE OR TWO. EXPECT THIS ROUND OF
RAIN TO EXIT EAST OF BOTH TAF SITES BY 12Z WITH SOME VERY LIGHT
RAIN OR DRIZZLE LEFT IN ITS WAKE WITH THE VISIBILITY RETURNING TO
MVFR WHILE CEILINGS STAY IFR. MODEL SOUNDINGS FROM THE NAM AND
09.21Z RAP SHOW THE POTENTIAL FOR FZRA/DZ AT KRST LATE TONIGHT
INTO WEDNESDAY MORNING. CONCERNED THAT THESE SOUNDINGS MAY BE TOO
COLD AND HAVE GONE WITH THE IDEA THAT TEMPERATURES WILL REMAIN AT
OR ABOVE FREEZING WITH THE MAIN PRECIPITATION TYPE STAYING LIQUID.
DID INCLUDE A TEMPO GROUP TO COVER THE POSSIBILITY OF SOME FZDZ IN
THE EVENT TEMPERATURES BRIEFLY DROP BELOW FREEZING. THEN EXPECTING
THE LIGHT DRIZZLE TO BE AROUND FOR MOST OF THE DAY BEFORE THE NEXT
SHORT WAVE TROUGH PUSHES IN THE THIRD ROUND OF RAIN FOR WEDNESDAY
AFTERNOON.
&&
.HYDROLOGY...TONIGHT THROUGH THURSDAY
ISSUED AT 359 PM CDT TUE APR 9 2013
THE RIVERS ARE CONTINUING TO RUN AT OR ABOVE BANKFULL IN
WISCONSIN NORTH OF INTERSTATE 90 AND JUST BELOW OR BELOW BANK FULL
IN SOUTHWEST WISCONSIN. WITH ANYWHERE FROM 1 TO 3 INCHES OF RAIN
EXPECTED FROM TODAY THROUGH THURSDAY. THERE CONTINUES TO BE
CONCERN THAT THIS PROLONG THE EXISTING FLOODING ALONG THE BLACK
AND TREMPEALEAU RIVERS...AND POSSIBLY RESULT IN ADDITIONAL
FLOODING ALONG OTHER RIVERS IN WESTERN WISCONSIN. DUE TO
THIS...KEPT THE FLOOD WATCH GOING FROM TODAY THROUGH THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...FLOOD WATCH THROUGH THURSDAY EVENING FOR WIZ017-029-032>034-
041>044-053>055-061.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR WIZ017-029-032>034.
MN...FLOOD WATCH THROUGH THURSDAY EVENING FOR MNZ079-086>088-094>096.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR MNZ079-086>088.
IA...FLOOD WATCH THROUGH THURSDAY EVENING FOR IAZ008>011-018-019-029-
030.
&&
$$
SHORT TERM...DAS
LONG TERM...DAS/JRW
AVIATION...04
HYDROLOGY...DAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1227 PM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
437 AM UPDATE...NOTICED THAT BOTH THE 08.00Z ECMWF AND 08.00Z/06Z
NAM INDICATE A DRY SLOT COMING THROUGH ALOFT TO SCOUR OUT THE ICE IN
THE CLOUDS FOR WEDNESDAY NIGHT AND THURSDAY. IF THIS COMES TO
FRUITION...WE MAY BE DEALING MORE WITH RAIN / FREEZING RAIN VERSUS
SNOW...AND THUS BACK TO WONDERING ABOUT OBJECT TEMPERATURES.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...THROUGH 18Z TUESDAY
1227 PM CDT MON APR 8 2013
PESKY MVFR/IFR STRATUS IN PACE ACROSS THE AREA BEHIND A DEPARTING
MID-LEVEL SHORTWAVE. VISIBLE SATELLITE WAS SHOWING SOME EROSION ON
THE SOUTHERN FRINGES OF THIS STRATUS ACROSS NORTHEAST IA INTO FAR
SOUTHWEST IA. RAP/NAM MODEL LAYER HUMIDITY AND SOUNDING
SHOWING THIS MIXING/SCATTERING REMAINING JUST SOUTH OF THE
KRST/KLSE TAF SITES THROUGH THIS AFTERNOON. SO...LOOKS LIKE KRST
WILL IMPROVE INTO MVFR CONDITIONS THIS AFTERNOON WITH KLSE REMAINING
IN MVFR CLOUDS. MESSY WEATHER PATTERN THEN SETTING UP ACROSS THE
AREA OVER THE NEXT 24 HOURS. LOW PRESSURE WILL MOVE OUT INTO THE
PLAINS TONIGHT...PUSHING A WARM FRONT AND SURGE OF MOISTURE TOWARD
THE REGION. THIS WILL LEAD TO RAIN DEVELOPING AFTER MIDNIGHT WITH
DETERIORATION IN CIGS/VIS INTO IFR RANGE AFTER 08Z.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...DAS
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
654 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
437 AM UPDATE...NOTICED THAT BOTH THE 08.00Z ECMWF AND 08.00Z/06Z
NAM INDICATE A DRY SLOT COMING THROUGH ALOFT TO SCOUR OUT THE ICE IN
THE CLOUDS FOR WEDNESDAY NIGHT AND THURSDAY. IF THIS COMES TO
FRUITION...WE MAY BE DEALING MORE WITH RAIN / FREEZING RAIN VERSUS
SNOW...AND THUS BACK TO WONDERING ABOUT OBJECT TEMPERATURES.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 654 AM CDT MON APR 8 2013
A LOW PRESSURE SYSTEM WILL PRODUCE SHOWERS AT KLSE THROUGH
08.15Z. IN THE WAKE OF THIS FRONT...SUBSIDENCE WILL BUILD ACROSS
THE REGION. THE BUFKIT SOUNDINGS SUGGEST THAT A MVFR DECK WILL
BECOME TRAPPED UNDER THE SUBSIDENCE INVERSION. HOWEVER THINKING
THAT THE MODELS MIGHT BE HAVING ISSUES WITH THE LOW LEVEL MOISTURE
FROM THE DENSE FOG ACROSS SOUTHWEST MINNESOTA AND NORTHWEST IOWA.
IF THIS WAS EARLIER IN THE NIGHT WOULD EXPECT THAT OUR AREA WOULD
ALSO SEE DENSE FOG AND LOW CEILINGS. HOWEVER WITH THE SUN ALREADY
UP...THINKING THAT THE PROBABILITIES FOR THIS OCCURRING IS MUCH
LOWER...SO OPTED TO GO MORE OPTIMISTIC AND JUST WENT WITH SOME
SCATTERED MVFR CLOUDS.
FOR TONIGHT...ANOTHER LOW PRESSURE SYSTEM WILL MOVE INTO THE
REGION. WENT WITH THE SLOWER GFS AND ECMWF SOLUTIONS...SO DELAYED
THE ONSET OF THE RAIN SHOWERS BY ABOUT 6 HOURS IN THE TAFS. THIS
WOULD MEAN ASTART OF AROUND 09.08Z FOR KRST AND 09.10Z FOR KLSE.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION...BOYNE
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
437 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 437 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
437 AM UPDATE...NOTICED THAT BOTH THE 08.00Z ECMWF AND 08.00Z/06Z
NAM INDICATE A DRY SLOT COMING THROUGH ALOFT TO SCOUR OUT THE ICE IN
THE CLOUDS FOR WEDNESDAY NIGHT AND THURSDAY. IF THIS COMES TO
FRUITION...WE MAY BE DEALING MORE WITH RAIN / FREEZING RAIN VERSUS
SNOW...AND THUS BACK TO WONDERING ABOUT OBJECT TEMPERATURES.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 7 2013
A COUPLE NORTHEAST MOVING UPPER AIR DISTURBANCES WILL BRING SWATHS
OF -SHRA ACROSS THE REGION...ONE TRACKING ACROSS SOUTHERN MN INTO
NORTHERN WI WITH THE OTHER ACROSS IOWA INTO SOUTHEAST WI. THE BULK
OF THE ACCUMULATIONS WILL BE NORTH AND SOUTH OF THE TAF SITES AS A
RESULT. ENOUGH FORCING FOR SCT/OCNL -SHRA AT KRST/KLSE OVERNIGHT
INTO THE MID MORNING HOURS OF MONDAY. CLOUDS WILL THICKEN AND
LOWER...WITH A PERIOD OF MVFR LIKELY. SEE SOME POTENTIAL OF IFR AT
KRST...PER RAP13/NAM12 BUFKIT SOUNDINGS.
THE SHORTWAVES EXIT MONDAY AFTERNOON...AND WITH SOME MIXING IN THE
LOWER ATMOSPHERE...THERE IS A GOOD CHANCE THAT THE BKN MVFR CIGS MIX
OUT TO SCT. ANY BREAK INTO SCATTERED SKIES WON/T LAST LONG. LOW
CLOUDS WILL QUICKLY RETURN MONDAY NIGHT AS A WARM FRONT SETS UP WEST
TO EAST ACROSS IOWA. RAIN WILL ALSO RETURN LATE THAT
EVENING...WITH TUE LOOKING LIKE A WET DAY. MVFR/IFR CIGS WILL
OCCUR...WITH SOME REDUCTIONS IN VSBY.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
HYDROLOGY...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
350 AM CDT MON APR 8 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 350 AM CDT MON APR 8 2013
CURRENTLY AS OF 08Z...WATER VAPOR LOOP AND RAP 500MB HEIGHT ANALYSIS
SHOWED A POTENT UPPER TROUGH DROPPING SOUTH THROUGH THE SIERRA
NEVADA OF CALIFORNIA...RIDGING BEGINNING TO BUILD DOWNSTREAM OVER
THE PLAINS...A SHORTWAVE OVER CENTRAL MINNESOTA AND ANOTHER
SHORTWAVE IN SOUTHEAST IOWA. ALSO OF NOTE IS A WEST TO EAST ORIENTED
UPPER TROUGH OVER NORTHERN ONTARIO...WITH A 70 KT JET STREAK AROUND
250MB LOCATED SOUTH OF IT. DPVA ASSOCIATED WITH THE CENTRAL
MINNESOTA SHORTWAVE AND RIGHT ENTRANCE REGION SUPPORT FROM THE
AFOREMENTIONED JET STREAK HAS LED TO AN AREA OF SHOWERS...AFFECTING
CENTRAL MN...NORTHWEST WI AND NORTHWEST PORTIONS OF THE FORECAST
AREA. MEANWHILE TO THE SOUTH...SHOWERS AND THUNDERSTORMS PERSIST
ACROSS NORTHERN MISSOURI INTO EASTERN IOWA ASSOCIATED WITH THE
SHORTWAVE THERE. THE SHOWERS AND STORMS ARE ALSO AIDED BY A 40-50 KT
LOW LEVEL JET AT 850MB ON PROFILER AND VAD WIND DATA...TRANSPORTING
MOISTURE AND INSTABILITY FROM THE CENTRAL AND SOUTHERN PLAINS. GOES
DERIVED AND RAP PRECIPITABLE WATER DATA SHOWED VALUES OF 1-1.25
INCHES BEING TRANSPORTED NORTHEASTWARD ON THE LOW LEVEL JET. A WARM
FRONT COULD BE SEEN AT THE SURFACE SOUTH OF THE CONVECTION ALONG THE
MISSOURI/IOWA BORDER. SOUTH OF THIS FRONT...SURFACE DEWPOINTS ARE IN
THE MID TO UPPER 50S.
THE WEATHER PATTERN IS ABOUT TO BECOME MORE ACTIVE...ALL IN RESPONSE
TO THAT POTENT SHORTWAVE TROUGH OVER THE SIERRA NEVADA DIGGING
SOUTH. BY 12Z TUESDAY...ALL MODELS HAVE A DEEP TROUGH OVER THE
SOUTHWESTERN U.S...WITH A CLOSED LOW NEAR THE FOUR CORNERS...WHICH
FORCES STRONG RIDGING TO BUILD UP TOWARDS THE FORECAST AREA.
MEANWHILE...TO THE NORTH...THE WEST TO EAST ORIENTED UPPER TROUGH
OVER NORTHERN ONTARIO IS PROGGED TO DROP SOUTH TOWARDS LAKE
SUPERIOR...RESTRICTING SOME OF THE NORTHWARD PROGRESS OF THE UPPER
RIDGING. ADDITIONALLY...THE UPPER TROUGH DROPPING SOUTH TOWARDS THE
SUBTROPICAL RIDGE WILL END UP STRENGTHENING THE UPPER JET STREAK ON
ITS SOUTH SIDE. BY 12Z TUESDAY...MODELS SHOW A 120 JET STREAK FROM
NORTHERN MINNESOTA ACROSS LAKE SUPERIOR.
FOR THIS MORNING...FOCUS IS ON THE PAIR OF SHORTWAVES TRACKING
THROUGH MINNESOTA AND IOWA. MODELS ARE IN GOOD AGREEMENT SHOWING
THESE SHORTWAVES REACHING UPPER MICHIGAN AND LAKE MICHIGAN
RESPECTIVELY BY 18Z. EXPECTING THE SHOWERS CURRENTLY ASSOCIATED WITH
THEM TO FOLLOW THE SAME TRACK...WITH SUBSIDENCE IN THEIR WAKE
HELPING TO END THE PRECIPITATION.
DURING THE AFTERNOON...THERE ARE INDICATIONS OF A SHORTWAVE
CURRENTLY IN SOUTHEAST WYOMING TRACKING ACROSS THE FORECAST AREA
BETWEEN 18-21Z...AROUND PEAK HEATING. AT THE SAME TIME...THE WARM
FRONT CURRENTLY ALONG THE MO/IA BORDER IS PROGGED TO HAVE LIFTED
NORTH AT LEAST TO I-80...OR POSSIBLY AS FAR NORTH AS U.S. HIGHWAY
20. INITIALLY WOULD BE CONCERNED THAT CONVECTION COULD FIRE...BUT
SOUNDINGS SHOW ENOUGH CAPPING IN THE WAKE OF THE MORNING
SHORTWAVES...ALONG WITH JUST VERY WEAK CONVERGENCE ON THE FRONT TO
PRECLUDE CONVECTION. THUS...HAVE WENT WITH A DRY FORECAST FOR THE
AFTERNOON ALONG WITH CLEARING SKIES. WITH 850MB TEMPS CLIMBING TO
5-9C AND AFTERNOON SUN...WE SHOULD BE ABLE TO CLIMB INTO THE 60S
SOUTH OF I-90...AND MID 40S TO MID 50S TO THE NORTH.
FOR TONIGHT...DESPITE UPPER LEVEL RIDGING BUILDING UP TOWARDS THE
AREA...THE SURFACE WARM FRONT LOOKS LIKE IT WILL GET PUSHED SOUTH.
THIS IS DUE TO THE UPPER TROUGH DROPPING SOUTH THROUGH CANADA...
ALLOWING LOW LEVEL COLD CANADIAN AIR TO FLOW INTO THE NORTHERN
PLAINS. IN TURN...THE LOW LEVEL FRONTOGENESIS STRENGTHENS ON THE
FRONTAL BOUNDARY. THE 08.00Z NAM IS QUICK TO DEVELOP CONVECTION ON
THE FRONTAL BOUNDARY IN THE EVENING...BETWEEN 00-03Z OVER NORTHERN
IOWA AND FAR SOUTHWEST WI. MOST OTHER MODELS WAIT UNTIL AFTER 06Z TO
HAVE ANY PRECIPITATION ON THE FRONTAL BOUNDARY. WILL LEAN TOWARDS
THE MAJORITY AND CONSIDER THE EVENING MOSTLY DRY. IT SHOULD BE NOTED
THE NAM IS BY FAR THE FARTHEST NORTH WITH THE WARM FRONT TOO. AFTER
06Z...THERE ARE INDICATIONS OF ANOTHER SHORTWAVE COMING UP TOWARDS
THE FORECAST AREA AROUND THE RIDGE...REACHING CENTRAL OR NORTHEAST
IOWA BY 12Z TUESDAY. A STRONG SURGE OF MOISTURE TRANSPORT COMBINED
WITH THE RIGHT ENTRANCE REGION FORCING OF THE UPPER JET WOULD YIELD
PRECIPITATION DEVELOPING AND EXPANDING INTO THE FORECAST AREA.
OUTSIDE OF THE 08.00Z SPCWRF-NMM...ALL OTHER AVAILABLE GUIDANCE
DEPICTS THIS SCENARIO. THUS...HAVE RAISED PRECIPITATION CHANCES
TOWARDS LATE IN THE NIGHT OVER THE SOUTHWEST HALF OF THE FORECAST
AREA.
.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON APR 8 2013
SUMMARIZED BRIEFLY...WET TUESDAY THROUGH THURSDAY.
MODELS CONTINUE TO SLOWLY BECOME IN BETTER AGREEMENT WITH THE
EVOLUTION OF THE SOUTHWESTERN U.S. TROUGH AS IT HEADS INTO THE
PLAINS AND EVENTUALLY INTO THE FORECAST AREA BY LATE IN THE WEEK.
STILL...THERE ARE ISSUES TO BE RESOLVED WHICH HAVE IMPACTS ON THE
FORECAST. THIS CAN EASILY BE SEEN IN THE TRACK OF THE MAIN SURFACE
LOW ASSOCIATED WITH THE TROUGH...WHERE THE 08.00Z GFS HAS A FARTHER
SOUTHEAST TRACK RELATIVE TO THE FORECAST AREA COMPARED TO THE 08.00Z
NAM/UKMET/CANADIAN/ECMWF. A FARTHER SOUTHEAST TRACK WOULD MEAN MORE
OF THE COLD CANADIAN AIR DIVING DOWN INTO THE NORTHERN PLAINS
TONIGHT GETS ADVECTED INTO THE FORECAST AREA. THEREFORE TOO...THE
GFS ALLOWS MORE PRECIPITATION BETWEEN TUESDAY NIGHT AND THURSDAY TO
FALL AS SNOW. HAVE LEANED THE FORECAST MORE TOWARDS A CONSENSUS OF
THE REST OF THE MODEL GUIDANCE WITH A MORE NORTHWEST TRACK...THOUGH
NOT AS FAR NORTHWEST AS THE 08.00Z NAM. REGARDING SOME DETAILS...
FIRST...TUESDAY IS A LITTLE TRICKY. MODELS ARE IN GOOD AGREEMENT
THAT THE SHORTWAVE APPROACHING NORTHEAST IOWA LATE TONIGHT WILL MOVE
THROUGH THE AREA DURING THE DAY. AGAIN PLENTIFUL FORCING IS PRESENT
BETWEEN THE RIGHT ENTRANCE REGION OF THE UPPER JET...THE SURGE OF
850MB MOISTURE TRANSPORT AND DPVA FROM THE SHORTWAVE. MOISTURE IS
ALSO PLENTIFUL WITH PRECIPITABLE WATER VALUES CLIMBING UP TO AN INCH
OR SO. THUS...SEEING PRECIPITATION LOOKS LIKE A SAFE BET. THE BIG
ISSUE IS THE QPF. THE 08.00Z GFS/NAM/REGIONAL CANADIAN AND HIRES-ARW
MODELS ALL SHOW POTENTIAL OF OVER AN INCH OF QPF TO FALL OVER THE
NORTHWEST HALF OF THE FORECAST AREA. THIS IS AN AREA THAT DOES NOT
NEED THE RAIN... PARTICULARLY OVER WEST CENTRAL WISCONSIN WHERE
FLOOD WARNINGS ARE OUT ON THE TREMPEALEAU AND BLACK RIVER. ON THE
OTHER HAND...THE 08.00Z ECMWF AND ITS PREVIOUS RUN DEPICT THE UP TO
AN INCH OF QPF TO FALL MORE TO THE SOUTH. HPC PREFERRED THE ECMWF
SCENARIO AND HAVE WENT ALONG WITH IT. DEFINITELY NEED TO WATCH WHERE
THE QPF FALLS. ALSO ADDED A SLIGHT CHANCE OF THUNDER FOR THE ENTIRE
DAY SOUTH OF I-90...CORRELATING WITH SOME WEAK ELEVATED CAPE PRESENT.
TUESDAY NIGHT AND EVEN WEDNESDAY CONTINUE TO LOOK LIKE A SLAM DUNK
FOR PRECIPITATION...ESPECIALLY TUESDAY NIGHT. DURING THIS PERIOD A
NEW SURGE OF 850MB MOISTURE TRANSPORT FORMS AHEAD OF THE EASTWARD
PROGRESSING UPPER TROUGH...IMPINGING INTO THE TIGHT LOW TO MID LEVEL
FRONTOGENESIS ZONE IN PLACE. ADDITIONALLY...THAT UPPER JET STREAK
JUST LINGERS OVER UPPER MICHIGAN TO PROVIDE UPPER LEVEL DIVERGENCE
OVER THE FORECAST AREA. WITH PRECIPITABLE WATER VALUES CONTINUING TO
HOVER IN AT LEAST THE 0.75 TO 1 INCH RANGE...HIGHEST IN THE
SOUTH...DEFINITE CONCERN HERE FOR AT LEAST MODERATE TO POSSIBLY
HEAVY PRECIPITATION. NOTE THE WORD PRECIPITATION HERE. ALL MODELS
SHOW THAT THE LOW LEVEL NORTHEAST FLOW ON THE NORTH SIDE OF THE
SURFACE LOW WILL DRAG DRIER...COLDER AIR SOUTH INTO THE AREA FROM
ONTARIO. AS A RESULT...WE ARE GOING TO RUN INTO A SITUATION OF COLD
AIR UNDERCUTTING A WARM LAYER...WHICH MEANS POTENTIAL FOR MIXED
PRECIPITATION TYPES. THE BIG QUESTION MARKS ARE:
1. DO 2 METER TEMPERATURES FALL BELOW FREEZING TUESDAY NIGHT AND
2. IF SO...WILL THE WARM LAYER STILL BE WARM ENOUGH TO ALLOW FOR
LIQUID AND
3. ARE OBJECTS GOING TO GET COLD ENOUGH TO RESULT IN ICE ACCUMULATION
FOR NOW HAVE INTRODUCED BOTH A MENTION OF SLEET AND FREEZING RAIN
INTO NORTHWEST SECTIONS OF THE FORECAST AREA AFTER MIDNIGHT TUESDAY
NIGHT INTO WEDNESDAY MORNING. THIS WOULD MOST LIKELY BE THE AREA
THAT SEES THE COLDEST LOW LEVEL AIR. ANTICIPATING THAT DIURNAL
HEATING ON WEDNESDAY SHOULD BOOST TEMPERATURES WARM ENOUGH TO RESULT
MAINLY IN RAIN BY AFTERNOON. STILL...ENDED UP COOLING HIGH
TEMPERATURES SOME DUE TO ANTICIPATION OF RAIN ALL DAY.
HEADING INTO WEDNESDAY NIGHT AND THURSDAY...ATTENTION TURNS TO
ACCUMULATING SNOW POTENTIAL AS THE CORE OF THE UPPER TROUGH MOVING
FROM THE CENTRAL PLAINS INTO THE FORECAST AREA. A VERY GOOD FORCING
SIGNAL SHOWS UP FOR PRECIPITATION BETWEEN 500MB HEIGHTS FALLING AND
A TROWAL WRAPPING BACK TOWARDS THE FORECAST AREA. RAISED
PRECIPITATION CHANCES GIVEN THE GOOD SIGNAL. 850MB TEMPS COOL AS THE
UPPER TROUGH APPROACHES...DOWN TO 0 TO -6C BY 12Z THURSDAY...
COLDEST NORTHWEST. FURTHER COOLING CONTINUES THROUGH THE DAY
THURSDAY. LOWERED BOTH LOW AND HIGH TEMPERATURES FOR THIS PERIOD.
HOW MUCH SNOW FALLS IS GOING TO DEPEND ON RATE...WARMTH OF THE
BOUNDARY LAYER AND GROUND TEMPERATURES. HARD TO SPECULATE ON AMOUNTS
AT THIS TIME...BUT A FEW INCHES OF ACCUMULATION SEEM POSSIBLE...
ESPECIALLY OVER THE NORTHWEST HALF OF THE AREA.
BEYOND THURSDAY...MODELS ARE STRUGGLING WITH HOW FAST TO LIFT OUT
THE UPPER TROUGH. THE NEW 08.00Z ECMWF REALLY SLOWED IT DOWN
COMPARED TO ITS PREVIOUS RUN AND OTHER MODEL GUIDANCE...WITH AN
UPPER LOW STILL OVER NORTHERN WISCONSIN AT 00Z SATURDAY. IF THIS
COMES TO FRUITION...POTENTIAL FOR SOME MINOR SNOW ACCUMULATIONS
WOULD CONTINUE AT LEAST INTO FRIDAY MORNING. ALL OTHER GUIDANCE
SUGGESTS THE TROUGH IS AT LEAST OVER THE EASTERN GREAT LAKES AT THIS
TIME...ALLOWING CANADIAN HIGH PRESSURE TO BUILD INTO MINNESOTA. FOR
NOW...STAYED WITH A CONSENSUS APPROACH WHICH IS TO KEEP SOME 20-30
PERCENT CHANCES IN THURSDAY NIGHT AND A DRY FRIDAY. DRY AND COOL
CONDITIONS LOOK TO PERSIST INTO AT LEAST SATURDAY AS THAT CANADIAN
HIGH MOVES THROUGH. ATTENTION THEN TURNS TO BROAD TROUGHING FORMING
OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES FOR THE REST OF THE
WEEKEND. 08.00Z ECMWF/GFS/GFS ENSEMBLES ALL HAVE A POTENT SHORTWAVE
COMING OUT OF THIS TROUGH AND HEADING INTO NORTHERN MN BY 00Z
MONDAY. WARM ADVECTION AHEAD OF THIS TROUGH EXPECTED TO YIELD SOME
RAIN...AND POSSIBLY SNOW INITIALLY UNTIL THE BOUNDARY LAYER WARMS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1100 PM CDT SUN APR 7 2013
A COUPLE NORTHEAST MOVING UPPER AIR DISTURBANCES WILL BRING SWATHS
OF -SHRA ACROSS THE REGION...ONE TRACKING ACROSS SOUTHERN MN INTO
NORTHERN WI WITH THE OTHER ACROSS IOWA INTO SOUTHEAST WI. THE BULK
OF THE ACCUMULATIONS WILL BE NORTH AND SOUTH OF THE TAF SITES AS A
RESULT. ENOUGH FORCING FOR SCT/OCNL -SHRA AT KRST/KLSE OVERNIGHT
INTO THE MID MORNING HOURS OF MONDAY. CLOUDS WILL THICKEN AND
LOWER...WITH A PERIOD OF MVFR LIKELY. SEE SOME POTENTIAL OF IFR AT
KRST...PER RAP13/NAM12 BUFKIT SOUNDINGS.
THE SHORTWAVES EXIT MONDAY AFTERNOON...AND WITH SOME MIXING IN THE
LOWER ATMOSPHERE...THERE IS A GOOD CHANCE THAT THE BKN MVFR CIGS MIX
OUT TO SCT. ANY BREAK INTO SCATTERED SKIES WON/T LAST LONG. LOW
CLOUDS WILL QUICKLY RETURN MONDAY NIGHT AS A WARM FRONT SETS UP WEST
TO EAST ACROSS IOWA. RAIN WILL ALSO RETURN LATE THAT
EVENING...WITH TUE LOOKING LIKE A WET DAY. MVFR/IFR CIGS WILL
OCCUR...WITH SOME REDUCTIONS IN VSBY.
&&
.HYDROLOGY...
ISSUED AT 350 AM CDT MON APR 8 2013
RIVER STATUS...
THE TREMPEALEAU RIVER NEAR DODGE WILL REMAIN ABOVE FLOOD STAGE AND
ALLOW FOR MINOR FLOODING TO CONTINUE THROUGH AT LEAST THIS EVENING.
THE BLACK RIVER AT BLACK RIVER FALLS IS ANTICIPATED TO EXPERIENCE
MINOR FLOODING THIS EVENING AND THROUGH THE DAY TUESDAY. THE REST OF
THE BLACK RIVER IS ALSO EXPECTED TO SEE WITHIN BANK RISES OVER THE
NEXT SEVERAL DAYS. OTHER RIVERS ACROSS THE AREA WILL LIKELY SEE
WITHIN BANK RISES WITH PERIODIC RAINFALL OVER THE NEXT SEVERAL DAYS
BUT ARE NOT EXPECTED TO FLOOD AT THIS TIME.
SNOW PACK...
RECENT COOPERATIVE OBSERVER REPORTS SHOW SNOW PACK IS MAINLY ALONG
AND NORTH OF HIGHWAY 10 WITH 2 TO 4 INCHES OF SNOW DEPTH IN PLACES.
THE DEEPEST SNOW PACK IS OVER THE NORTHERN MOST PARTS OF TAYLOR
WHERE AROUND 4 TO 6 INCHES OF SNOW REMAINS ON THE GROUND. SNOW WATER
EQUIVALENT OF 2 TO 4 INCHES IS MAINLY NORTH OF HIGHWAY 10 WITH THE
GREATEST SNOW WATER EQUIVALENT IN NORTHERN TAYLOR COUNTY.
RAINFALL...
BEFORE NOON...COULD SEE UPWARDS OF 1/4 INCH OR SO OF RAINFALL...
GREATEST OVER TAYLOR COUNTY. ATTENTION THEN TURNS TO THE LATE
TONIGHT THROUGH WEDNESDAY TIME PERIOD WHERE PERIODS OF RAINFALL
COULD TOTAL FROM 1 TO 3 INCHES. THE HEAVIEST RAINFALL RIGHT NOW IS
ANTICIPATED SOUTH OF INTERSTATE 90...WHERE RIVERS HAVE A BETTER
CHANCE OF HANDLING IT. HOWEVER...THERE IS SOME UNCERTAINTY AND
HEAVIER RAINFALL COULD OCCUR FARTHER NORTH THAN EXPECTED.
TEMPERATURES...
HIGHS TODAY ARE EXPECTED TO BE AROUND 50 NORTH OF I-94 TO THE LOWER
TO MIDDLE 60S SOUTH OF I-90. HIGHS WILL COOL QUITE A BIT FOR TUESDAY
THROUGH THURSDAY...ESPECIALLY FOR THURSDAY WHERE READINGS MAY NOT
REACH 40. STILL...THESE TEMPERATURES WILL CONTINUE TO MELT ANY
EXISTING SNOWPACK.
FROST DEPTH...
AS OF APRIL 4TH...FROST DEPTHS //WHICH ARE OBSERVED EVERY MONDAY AND
THURSDAY//ACROSS THE AREA REMAIN DEEP...AVERAGING AROUND 1 FOOT TO 1
1/2 FEET SOUTH OF I-90...AND UP TO 3 FEET ACROSS PORTIONS OF NORTH
CENTRAL WISCONSIN. THIS FROST WILL ACT TO ENHANCE RUNOFF OF SNOW
MELT AND PRECIPITATION INTO STREAMS AND RIVERS.
SUMMARY...
POSSIBILITY OF FLOODING REMAINS A CONCERN THROUGH THIS WEEK WITH
ADDITIONAL SNOW MELT AND ESPECIALLY THE RAINFALL LATE TONIGHT
THROUGH WEDNESDAY. OVERALL...APPEARS THE BIGGEST FLOODING CONCERNS
ARE ALONG THE BLACK AND TREMPEALEAU RIVERS FOR THE NEXT FEW DAYS.
WILL CONTINUE TO KEEP AND EYE ON THIS. HAVE A HYDROLOGIC OUTLOOK
PRODUCT OUT TO HEIGHTEN THIS AWARENESS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM...AJ
AVIATION.....RIECK
HYDROLOGY...AJ
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
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 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 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
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 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 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 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 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 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 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 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 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 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 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 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 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 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
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 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 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 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 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 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 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 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 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