Forecast Discussions mentioning any of
"HRRR" "RAP" "RR" "RUC13" "RUC" received at GSD on 04/11/13
AREA FORECAST DISCUSSION
NWS PUEBLO CO
320 PM MDT TUE APR 9 2013
.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 WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ059-
064-069>071-074-075-081>088.
WINTER STORM WARNING UNTIL 9 PM MDT THIS EVENING FOR COZ058-060-
066-068.
&&
$$
SHORT TERM...KT
LONG TERM...MOORE
AVIATION...KT
AREA FORECAST DISCUSSION
NWS TAUNTON MA
846 PM EDT WED APR 10 2013
.SYNOPSIS...
ANOTHER ROUND OF RAIN SHOWERS WILL CONTINUE INTO TONIGHT AS A
WAVE LOW PRESSURE TRACKS ACROSS THE REGION. COOLER AIR WILL FILTER
INTO THE REGION ON NORTHEAST WINDS THROUGH THE END OF THE WEEK. A
STRONG FRONT WILL BRING A SOAKING RAIN FRIDAY AFTERNOON AND
EVENING. DRY AND MORE SEASONABLE WEATHER RETURNS FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
845 PM UPDATE...
EARLIER LINE OF SHOWERS/STORMS WEAKENED AS IT BEGAN TO ENCOUNTER
MARINE LAYER OVER CT/RI AND OUT RAN SURFACE THETA RIDGE. EXPECT
BRIEFLY HEAVY RAINFALL WITH THIS ACTIVITY AS IT PUSHES ACROSS CAPE
COD AND ISLANDS THROUGH 10 PM.
NORTHERN BATCH OF SHOWERS HAS MOVED OFFSHORE FOR MOST PART WITH
ADDITIONAL LIGHTER SHOWERS BEHIND IT. THESE WILL PERSIST UNTIL
MIDNIGHT OR SO PER 13KM RAP WHICH HAS A GOOD HANDLE ON RADAR
TRENDS.
FARTHER UPSTREAM...WE ARE WATCHING YET ANOTHER COMPLEX OF
SHOWERS/ISOLATED THUNDER HEADING IN FROM S CENTRAL NY/NORTHERN PA.
THIS ACTIVITY SHOULD DIMINISH AS IT ENCOUNTERS A MORE STABLE
AIRMASS OVER SOUTHERN NEW ENGLAND...AND IN FACT STRONGER
CONVECTION ON ITS SOUTHERN FLANK OVER SE PA MAY ROB MOST OF
MOISTURE AS IT REACHES NJ.
MODIFIED HOURLY POPS TO REFLECT ABOVE TRENDS. ANTICIPATE MOST OF
SHOWERS TO COME TO AN END BETWEEN 11 PM AND 2 AM...LEAVING CLOUDY
SKIES/PATCHY FOG IN ITS WAKE.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
THURSDAY...
A RATHER CLOUDY AND COOL DAY IS ON TAP FOR SOUTHERN NEW ENGLAND.
MOST OF ANY LINGERING LIGHT SHOWERS/DRIZZLE SHOULD COME TO AN END BY
MID MORNING. STRONG HIGH PRESSURE OVER EASTERN CANADA WILL
TEMPORARILY NOSE DOWN AND SEND DRIER LOW LEVEL AIR ACROSS OUR
REGION. THEREFORE...WHILE WE CAN/T RULE OUT A SPOT SHOWER OR TWO
MAINLY DRY WEATHER IS ON TAP FOR MOST OF THE DAY. A FEW SHOWERS MAY
WORK INTO OUR WESTERN ZONES TOWARD EVENING IN ADVANCE OF LOW
PRESSURE...BUT AGAIN DRY WEATHER IS ANTICIPATED FOR MOST OF THE DAY.
HIGH TEMPS ACROSS THE REGION SHOULD GENERALLY BE IN THE UPPER 40S
AND LOWER 50S ACROSS MOST LOCATIONS.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
HIGHLIGHTS...
* STRONG FRONT WILL MOVE THROUGH ON FRIDAY
* MODERATING TEMPS FOR THE WEEKEND...INCREASING FOR NEXT WEEK
CONFIDENCE LEVEL/MODEL GUIDANCE...
12Z MODEL GUIDANCE CONTINUES TO DECREASE THE MODEL
SPREAD...THEREFORE CONFIDENCE IS INCREASING. SEEMS THAT THE 12Z
NAM IS THE OUTLIER OF THE DAY BEING THE COLDER AND FASTEST
SOLUTION COMPARED TO REST OF THE MODEL SUITE. THE 12Z EC HAS
SHIFTED ITS LOW FARTHER SOUTH TO BE MORE IN LINE WITH THE GFS
WHILE THE GFS HAS WARMED ITS THERMAL PROFILE SLIGHTLY COMPARED TO
ITS PREV RUN. OVERALL THE EC/GFS ARE QUITE SIMILAR AND THIS IS
SUPPORTED BY THEIR ENSEMBLES AS WELL. OVERALL CONFIDENCE IS HIGH
WITH THE FORECAST UNTIL EARLY NEXT WEEK WHERE IT DROPS TO MODERATE
THANKS TO THE LESS AMPLIFIED GFS FOR MONDAY INTO TUESDAY.
DETAILS...
THURSDAY NIGHT INTO FRIDAY MORNING...
TRICKY FORECAST STILL IS IN STORE. THERMAL PROFILES FOR THE GFS/EC
ARE QUIET SIMILAR SO BLENDED THE TWO TOGETHER. THE 12Z NAM IS
QUIET COLDER AND REMAINS THE OUTLIER...THEREFORE HAVE THROWN IT
OUT OF THE FORECAST. OVERALL STATIONARY BOUNDARY WILL PUSH SOUTH
OF THE REGION BY THURSDAY NIGHT ALLOWING FOR COOLER CONDITIONS.
WITH THE OVERCAST SKY...BELIEVE TEMPS WILL HOLD STEADY BY
MIDNIGHT. EXPECT 800-850MB WARM NOSE TO BEGIN TO INTRUDE INTO THE
REGION BY EARLY FRI MORNING. SHALLOW COLD AIR...THANKS TO COLD AIR
DAMMING...WILL KEEP SURFACE TEMPS AT OR BELOW FREEZING ESP IN SOUTHERN
NH. AS PRECIP BEGINS...INTENSITY WILL BE QUITE LIGHT SO BELIEVE
FREEZING DZ/RA IS POSSIBLE COMBINED WITH SLEET. ICE ACCRETION IS
POSSIBLE ACROSS THE HIGHER ELEVATIONS...BUT DUE TO THE WARM
GROUND...ACCUMS WILL OCCUR ON TREES/POWER LINES ETC.
FRIDAY DAY INTO THE OVERNIGHT HOURS...
WARM FRONT WILL REMAIN STATIONARY FOR MOST OF THE DAY...AS
SURFACE LOW WILL DEVELOP FROM THE MID-ATLANTIC AND MOVE TOWARDS
ACK. AS THE LOW APPROACHES THE REGION...WARM FRONT WILL LIFT
NORTHWARD...PERHAPS CLIPPING THE SOUTH COAST. THIS MAY ALLOW THEM
TO WARM UP INTO THE 50S WHILE THE REST OF THE REGION WILL BE IN
THE 40S. REGARDLESS...AS SURFACE LOW PASSES OVER THE
REGION...GIVEN THE DECENT DYNAMICS AND STRONG LIFT STILL EXPECTING
SOME DECENT PRECIPITATION OUT OF THIS SYSTEM. MOISTURE CONNECTION
FROM THE GULF OF MEXICO AND PWAT VALUES NEARING 1.25 INCHES WILL
ALLOW FOR SOME DECENT PRECIP. MODELS HAVE SPED THIS SYSTEM UP A
FEW HOURS...SO EXPECT IT PUSH OUT OF THE REGION BY EVENING HOURS.
WITH GOOD MOISTURE TRANSPORT AND A 45-50 KT 850 JET...BELIEVE THE
HEAVY DOWNPOURS ARE POSSIBLE. MAIN THREAT IS URBAN AND POOR
DRAINAGE FLOODING...EVEN FLASHY STREAMS NEED TO WATCHED CLOSELY.
HOWEVER MAIN STEM RIVERS BASINS WILL BE ABLE TO HANDLE THIS AMOUNT
OF PRECIP.
THE WEEKEND...
SURFACE LOW WILL MOVE OFF SHORE WHILE UPPER LEVEL TROUGH WILL
REMAIN ACROSS THE UPPER GREAT LAKES. THIS TROUGH WILL MOVE THROUGH
THE REGION DURING THE WEEKEND PROVIDING A MIX OF SUN AND CLOUDS.
TEMPS WILL BE COOLER THAN ORIGINALLY THOUGHT Y-DAY...WITH MAX
TEMPS IN THE MID TO UPPER 50S.
EARLY WORK WEEK...
MODEL SPREAD INCREASES SIGNIFICANTLY FOR THIS TIME FRAME. GFS IS
LESS AMPLIFIED AND THEREFORE PUSHES A SHORTWAVE THROUGH THE REGION
ON MONDAY WHILE THE EC AMPLIFIES THE RIDGE AND KEEPS HIGH PRESSURE
FOR THE AREA. LEANED WITH THE CONSISTENT HPC AND EC FOR THIS
PORTION. BOTH MODELS SHOW A STALLED FRONT ACROSS THE NORTHERN
PORTIONS OF NEW ENGLAND. THIS MAY IMPACT OUR WEATHER DURING THE
MID-WEEK WITH ANOTHER SYSTEM BY THE END OF THE WEEK. FOR NOW
CONTINUED WITH PREV FORECASTERS THINKING AND LEFT MAINLY DRY
FORECAST EXPECT FOR TUESDAY...WHERE CONFIDENCE IS SLOWLY
INCREASING.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
OVERVIEW...LOW TO MODERATE CONFIDENCE THROUGH THURSDAY AFTERNOON.
A COMPLEX OF SHOWERS AND THUNDERSTORMS WILL AFFECT THE
REGION...MAINLY THIS EVENING INTO PART OF THE OVERNIGHT HOURS. A
FEW ISOLATED THUNDERSTORMS ARE POSSIBLE WITH THE BETTER AREA ACROSS
NORTHERN CT/RI AND SOUTHEAST MA. LIGHT SHOWERS AND PATCHY DRIZZLE
MAY LINGER INTO THU MORNING...BUT THE HEAVIER PRECIPITATION SHOULD
COME TO AN END TOWARD DAYBREAK THU.
AS FOR CIGS/VSBYS EXPECT MVFR CONDITIONS WILL DEVELOP THIS
EVENING WITH PERHAPS A PERIOD OF IFR CONDITIONS ESPECIALLY TOWARD
DAYBREAK THU. SOME TEMPORARY IMPROVEMENT IN CONDITIONS IS LIKELY
ON THU AND MANY LOCATIONS SHOULD RETURN TO VFR...BUT TIMING IS
UNCERTAIN
KBOS TERMINAL...LOW TO MODERATE CONFIDENCE IN CONDITIONS AND TIMING.
THERE IS HIGH CONFIDENCE IN A PERIOD OF WET RUNWAYS THIS EVENING.
LOW PROBABILITY OF AN ISOLATED THUNDERSTORM THIS EVENING.
KBDL TERMINAL...LOW TO MODERATE CONFIDENCE IN CONDITIONS AND TIMING.
THERE IS HIGH CONFIDENCE IN A PERIOD OF WET RUNWAYS THIS EVENING.
LOW PROBABILITY OF AN ISOLATED THUNDERSTORM THIS EVENING.
OUTLOOK...FRIDAY THROUGH MONDAY...
THURSDAY NIGHT...MODERATE CONFIDENCE...VFR DROPPING TO MVFR AS
SHRA MOVE ACROSS THE REGION. LOW CLOUDS AND FOG ALSO POSSIBLE.
LATE THURS INTO FRI AM...IFR CONDITIONS POSSIBLE ACROSS NORTHERN
SITES IN SLEET/FREEZING RA...EVERYWHERE ELSE WILL SEE RAIN.
FRIDAY...MODERATE CONFIDENCE. 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. THE RAIN AND WIND SHEAR GRADUALLY DISSIPATE FRI NIGHT.
SATURDAY INTO MONDAY...HIGH CONFIDENCE. VFR.
&&
.MARINE...
FORECASTER CONFIDENCE LEVELS...
LOW...LESS THAN 30 PERCENT.
MODERATE...30 TO 60 PERCENT.
HIGH...GREATER THAN 60 PERCENT.
MODERATE TO HIGH CONFIDENCE TONIGHT AND THURSDAY. WEAK PRESSURE
GRADIENT SHOULD KEEP WINDS AND SEAS BELOW SCA FOR MOST OF THE
TONIGHT. WE DID HOIST SCA ACROSS THE OUTER WATERS BEGINNING EARLY
THU INTO THU AFTERNOON. HIGH PRESSURE NOSING DOWN FROM EASTERN
CANADA WILL RESULT IN NORTHEAST WIND GUSTS OF 20 TO 25 KNOTS ALONG
WITH 3 TO 5 FOOT SEAS. CONDITIONS ACROSS THE REST OF THE WATERS
SHOULD REMAIN BELOW SCA THRESHOLDS.
OUTLOOK...FRIDAY THROUGH SUNDAY...
MODERATE CONFIDENCE ALL PERIODS.
THURSDAY NIGHT INTO FRIDAY...
LOW PRESSURE SYSTEM WILL PUSH ACROSS THE WATERS FRI. AHEAD OF
THIS FRONT SE WINDS MAY GUST TO GALE FORCE AT TIMES. AT
LEAST...WINDS OF SMALL CRAFT ADVISORY LEVEL WILL AFFECT THE WATERS
WITH SEAS REACHING 5-8 FEET ARE LIKELY. HAVE ISSUED A GALE
WATCH...ALTHOUGH MARGINAL CONFIDENCE IS ABOVE 50 PERCENT. RAIN/FOG
WILL LEAD TO REDUCTIONS IN VISIBILITY ESPECIALLY FRI AFTERNOON AND
EVENING.
SATURDAY INTO SUNDAY... NORTHWEST WINDS GUSTING TO 25 KNOTS DUE TO
CAA. SEAS REMAIN ABOVE 5 FEET ESPECIALLY ON THE OUTER WATERS.
SMALL CRAFT ADVISORIES LIKELY CONTINUE.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
MA...NONE.
NH...NONE.
RI...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TO 4 PM EDT THURSDAY FOR
ANZ254>256.
GALE WATCH FROM LATE THURSDAY NIGHT THROUGH FRIDAY AFTERNOON
FOR ANZ255-256.
&&
$$
SYNOPSIS...FRANK/DUNTEN
NEAR TERM...JWD
SHORT TERM...FRANK
LONG TERM...DUNTEN
AVIATION...FRANK/DUNTEN
MARINE...FRANK/DUNTEN
AREA FORECAST DISCUSSION
NWS MIAMI FL
924 AM EDT TUE APR 9 2013
.UPDATE...
ALREADY MADE SOME ADJUSTMENTS TO THE MORNING UPDATES BASED ON
CURRENT TRENDS. MOST OF THAT WAS JUST TO CHANGE MOSTLY CLOUDY
WORDING TO PARTLY SUNNY. THERE HAVE BEEN ISOLATED SMALL SHOWERS
MOVING OFF THE ATLANTIC IN THE LOW LEVEL SOUTHEASTERLY FLOW. A
STRONG SUBSIDENCE CAP REMAINS IN PLACE AS DEPICTED FROM THE 12Z
MFL SOUNDING SO ANY ADDITIONAL ACTIVITY WILL CONTINUE LOW TOPPED
AND ISOLATED. MARINE ZONES ALSO LOOK TO BE IN GOOD SHAPE.
KOB
&&
.PREV DISCUSSION... /ISSUED 716 AM EDT TUE APR 9 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. THERE ARE A FEW SHOWERS SPREADING
ASHORE THIS MORNING JUST SOUTH OF THE PBI TERMINAL. THE LATEST
MODEL GUIDANCE INDICATES THIS LIGHT ACTIVITY CONTINUING THROUGH
THE EARLY MORNING HOURS. KAPF SHOULD SEE A GULF BREEZE DEVELOP BY
MID AFTERNOON.
PREV DISCUSSION... /ISSUED 402 AM EDT TUE APR 9 2013/
DISCUSSION...EXTENSIVE CIRRUS CLOUDS CONTINUE TO MOVE ACROSS
SOUTH FLORIDA AND THIS IS EXPECTED TO CONTINUE THROUGHOUT THE DAY,
SO HAVE GONE WITH MOSTLY CLOUDY SKIES AS THE CIRRUS IS RATHER
DENSE. MOISTURE REMAINS SPARSE, BUT THE HRRR SHOWS A FEW SHOWERS
MOVING INTO THE ATLANTIC BY MID MORNING. GIVEN THAT A FEW SHOWERS
CANNOT BE RULED OUT ALONG THE ATLANTIC COAST, DECIDED TO PLACE A
10 POP THERE TODAY-TONIGHT. THINKING IS THAT WITH THE ESE FLOW
PICKING UP A BIT, SLIGHT MOISTENING/CONVERGENCE COULD ACT TO
DEVELOP JUST A FEW SHOWERS. HOWEVER, MOST LOCALES WILL CONTINUE
TO BE DRY...A 90% CHANCE OF THAT.
AS A POWERFUL TROUGH OVER THE ROCKIES PULLS INTO THE PLAINS STATES
THROUGH THURSDAY (BRINGING A FULL-FLEDGED APRIL WINTER STORM FROM
THE ROCKIES TO THE UPPER MIDWEST!), A RIDGE WILL BE PUMPED UP
LOCALLY. THIS WILL LEAD TO WARMING TEMPS ALONG WITH INCREASING
HUMIDITY. LOW LEVEL MOISTURE WILL BE ON THE INCREASE ALONG WITH
THE CAP SLOWLY ERODING AS THE MID LEVEL RIDGE SLIDES OFF TO THE
EAST. THIS WILL SUPPORT THE RISK FOR THUNDERSTORMS BEGINNING
WEDNESDAY AND INTO THE UPCOMING WEEKEND. THE BEST CHANCE OF
TSTORMS WILL BE FRIDAY AND INTO THE UPCOMING WEEKEND AS THE COLD
FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH SLIDES DOWN THE
PENINSULA WITH MOISTURE POOLING ALONG/AHEAD OF IT. THE 09.00Z RUNS
OF THE GFS AND ECMWF ARE MORE IN SYNC AND SHOW THE COLD FRONT
MOVING TO THE LAKE REGION OR JUST NORTH WHILE STALLING AND
BECOMING DIFFUSE. AS THE ATMOSPHERE BECOMES INCREASINGLY MOIST AND
UNSTABLE ALONG/SOUTH OF THIS BOUNDARY, WE EXPECTED ISD-SCT TSTORMS
TO DEVELOP ESPECIALLY EACH AFTERNOON IN THE HEAT OF THE DAY. WHILE
THE MAIN ENERGY RIDES WELL NORTH OF THE AREA ON FRIDAY, BOTH
GFS/ECMWF DO SHOW A SUBTLE SHORTWAVE MOVING ACROSS SOUTH FL FROM
THE GULF OF MEXICO ON SATURDAY. ANY RIPPLES IN THE FLOW SUCH AS
THIS COULD ACT TO INVIGORATE TSTORMS GIVEN BOUNDARY PROXIMITY AND
A WARM, HUMID AND UNSTABLE AIRMASS EXPECTED TO BE IN PLACE.
THE DIFFUSE BOUNDARY LOOKS TO MOVE BACK TO THE NORTH EARLY NEXT
WEEK WITH LESSENING CHANCES OF SHRA/TSTORMS. TEMPS THROUGH THE
PERIOD WILL CONTINUE ABOVE AVERAGE WITH A NOTICEABLE INCREASE IN
HUMIDITY OVER THE COMING DAYS.
MARINE...EASTERLY WINDS WILL BECOME SE INCREASING WED-THU INTO
THE 15-20 KT RANGE...EVEN OVER THE ATLANTIC ON FRIDAY AS WINDS
BECOME MORE SOUTHERLY WITH THE APPROACH OF A COLD FRONT. TSTORMS
WILL BECOME POSSIBLE BY LATE WEEK, ESPECIALLY OVER THE UPCOMING
WEEKEND.
FIRE WEATHER...RELATIVE HUMIDITIES WILL REMAIN ABOVE CRITICAL
LEVELS DUE TO INCREASING HUMIDITY ON ESE WINDS BECOMING SE AND
EVENTUALLY SOUTHERLY THIS WEEKEND. THERE WILL BE AN INCREASING
CHANCE OF THUNDERSTORMS BY LATE IN THE WEEK WITH THE CONCERN FOR
WILDFIRES CAUSED BY LIGHTNING STRIKES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 82 73 / 10 10 20 20
FORT LAUDERDALE 81 75 83 74 / 10 10 20 20
MIAMI 82 73 84 74 / 10 10 20 20
NAPLES 87 68 88 70 / - - 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MIAMI FL
716 AM EDT TUE APR 9 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. THERE ARE A FEW SHOWERS SPREADING
ASHORE THIS MORNING JUST SOUTH OF THE PBI TERMINAL. THE LATEST
MODEL GUIDANCE INDICATES THIS LIGHT ACTIVITY CONTINUING THROUGH
THE EARLY MORNING HOURS. KAPF SHOULD SEE A GULF BREEZE DEVELOP BY
MID AFTERNOON.
&&
.PREV DISCUSSION... /ISSUED 402 AM EDT TUE APR 9 2013/
DISCUSSION...EXTENSIVE CIRRUS CLOUDS CONTINUE TO MOVE ACROSS
SOUTH FLORIDA AND THIS IS EXPECTED TO CONTINUE THROUGHOUT THE DAY,
SO HAVE GONE WITH MOSTLY CLOUDY SKIES AS THE CIRRUS IS RATHER
DENSE. MOISTURE REMAINS SPARSE, BUT THE HRRR SHOWS A FEW SHOWERS
MOVING INTO THE ATLANTIC BY MID MORNING. GIVEN THAT A FEW SHOWERS
CANNOT BE RULED OUT ALONG THE ATLANTIC COAST, DECIDED TO PLACE A
10 POP THERE TODAY-TONIGHT. THINKING IS THAT WITH THE ESE FLOW
PICKING UP A BIT, SLIGHT MOISTENING/CONVERGENCE COULD ACT TO
DEVELOP JUST A FEW SHOWERS. HOWEVER, MOST LOCALES WILL CONTINUE
TO BE DRY...A 90% CHANCE OF THAT.
AS A POWERFUL TROUGH OVER THE ROCKIES PULLS INTO THE PLAINS STATES
THROUGH THURSDAY (BRINGING A FULL-FLEDGED APRIL WINTER STORM FROM
THE ROCKIES TO THE UPPER MIDWEST!), A RIDGE WILL BE PUMPED UP
LOCALLY. THIS WILL LEAD TO WARMING TEMPS ALONG WITH INCREASING
HUMIDITY. LOW LEVEL MOISTURE WILL BE ON THE INCREASE ALONG WITH
THE CAP SLOWLY ERODING AS THE MID LEVEL RIDGE SLIDES OFF TO THE
EAST. THIS WILL SUPPORT THE RISK FOR THUNDERSTORMS BEGINNING
WEDNESDAY AND INTO THE UPCOMING WEEKEND. THE BEST CHANCE OF
TSTORMS WILL BE FRIDAY AND INTO THE UPCOMING WEEKEND AS THE COLD
FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH SLIDES DOWN THE
PENINSULA WITH MOISTURE POOLING ALONG/AHEAD OF IT. THE 09.00Z RUNS
OF THE GFS AND ECMWF ARE MORE IN SYNC AND SHOW THE COLD FRONT
MOVING TO THE LAKE REGION OR JUST NORTH WHILE STALLING AND
BECOMING DIFFUSE. AS THE ATMOSPHERE BECOMES INCREASINGLY MOIST AND
UNSTABLE ALONG/SOUTH OF THIS BOUNDARY, WE EXPECTED ISD-SCT TSTORMS
TO DEVELOP ESPECIALLY EACH AFTERNOON IN THE HEAT OF THE DAY. WHILE
THE MAIN ENERGY RIDES WELL NORTH OF THE AREA ON FRIDAY, BOTH
GFS/ECMWF DO SHOW A SUBTLE SHORTWAVE MOVING ACROSS SOUTH FL FROM
THE GULF OF MEXICO ON SATURDAY. ANY RIPPLES IN THE FLOW SUCH AS
THIS COULD ACT TO INVIGORATE TSTORMS GIVEN BOUNDARY PROXIMITY AND
A WARM, HUMID AND UNSTABLE AIRMASS EXPECTED TO BE IN PLACE.
THE DIFFUSE BOUNDARY LOOKS TO MOVE BACK TO THE NORTH EARLY NEXT
WEEK WITH LESSENING CHANCES OF SHRA/TSTORMS. TEMPS THROUGH THE
PERIOD WILL CONTINUE ABOVE AVERAGE WITH A NOTICEABLE INCREASE IN
HUMIDITY OVER THE COMING DAYS.
MARINE...EASTERLY WINDS WILL BECOME SE INCREASING WED-THU INTO
THE 15-20 KT RANGE...EVEN OVER THE ATLANTIC ON FRIDAY AS WINDS
BECOME MORE SOUTHERLY WITH THE APPROACH OF A COLD FRONT. TSTORMS
WILL BECOME POSSIBLE BY LATE WEEK, ESPECIALLY OVER THE UPCOMING
WEEKEND.
FIRE WEATHER...RELATIVE HUMIDITIES WILL REMAIN ABOVE CRITICAL
LEVELS DUE TO INCREASING HUMIDITY ON ESE WINDS BECOMING SE AND
EVENTUALLY SOUTHERLY THIS WEEKEND. THERE WILL BE AN INCREASING
CHANCE OF THUNDERSTORMS BY LATE IN THE WEEK WITH THE CONCERN FOR
WILDFIRES CAUSED BY LIGHTNING STRIKES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 82 73 / 10 10 20 20
FORT LAUDERDALE 81 75 83 74 / 10 10 20 20
MIAMI 82 73 84 74 / 10 10 20 20
NAPLES 87 68 88 70 / - - 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...30/KOB
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS MIAMI FL
402 AM EDT TUE APR 9 2013
.DISCUSSION...EXTENSIVE CIRRUS CLOUDS CONTINUE TO MOVE ACROSS
SOUTH FLORIDA AND THIS IS EXPECTED TO CONTINUE THROUGHOUT THE DAY,
SO HAVE GONE WITH MOSTLY CLOUDY SKIES AS THE CIRRUS IS RATHER
DENSE. MOISTURE REMAINS SPARSE, BUT THE HRRR SHOWS A FEW SHOWERS
MOVING INTO THE ATLANTIC BY MID MORNING. GIVEN THAT A FEW SHOWERS
CANNOT BE RULED OUT ALONG THE ATLANTIC COAST, DECIDED TO PLACE A
10 POP THERE TODAY-TONIGHT. THINKING IS THAT WITH THE ESE FLOW
PICKING UP A BIT, SLIGHT MOISTENING/CONVERGENCE COULD ACT TO
DEVELOP JUST A FEW SHOWERS. HOWEVER, MOST LOCALES WILL CONTINUE
TO BE DRY...A 90% CHANCE OF THAT.
AS A POWERFUL TROUGH OVER THE ROCKIES PULLS INTO THE PLAINS STATES
THROUGH THURSDAY (BRINGING A FULL-FLEDGED APRIL WINTER STORM FROM
THE ROCKIES TO THE UPPER MIDWEST!), A RIDGE WILL BE PUMPED UP
LOCALLY. THIS WILL LEAD TO WARMING TEMPS ALONG WITH INCREASING
HUMIDITY. LOW LEVEL MOISTURE WILL BE ON THE INCREASE ALONG WITH
THE CAP SLOWLY ERODING AS THE MID LEVEL RIDGE SLIDES OFF TO THE
EAST. THIS WILL SUPPORT THE RISK FOR THUNDERSTORMS BEGINNING
WEDNESDAY AND INTO THE UPCOMING WEEKEND. THE BEST CHANCE OF
TSTORMS WILL BE FRIDAY AND INTO THE UPCOMING WEEKEND AS THE COLD
FRONT ASSOCIATED WITH THE AFOREMENTIONED TROUGH SLIDES DOWN THE
PENINSULA WITH MOISTURE POOLING ALONG/AHEAD OF IT. THE 09.00Z RUNS
OF THE GFS AND ECMWF ARE MORE IN SYNC AND SHOW THE COLD FRONT
MOVING TO THE LAKE REGION OR JUST NORTH WHILE STALLING AND
BECOMING DIFFUSE. AS THE ATMOSPHERE BECOMES INCREASINGLY MOIST AND
UNSTABLE ALONG/SOUTH OF THIS BOUNDARY, WE EXPECTED ISD-SCT TSTORMS
TO DEVELOP ESPECIALLY EACH AFTERNOON IN THE HEAT OF THE DAY. WHILE
THE MAIN ENERGY RIDES WELL NORTH OF THE AREA ON FRIDAY, BOTH
GFS/ECMWF DO SHOW A SUBTLE SHORTWAVE MOVING ACROSS SOUTH FL FROM
THE GULF OF MEXICO ON SATURDAY. ANY RIPPLES IN THE FLOW SUCH AS
THIS COULD ACT TO INVIGORATE TSTORMS GIVEN BOUNDARY PROXIMITY AND
A WARM, HUMID AND UNSTABLE AIRMASS EXPECTED TO BE IN PLACE.
THE DIFFUSE BOUNDARY LOOKS TO MOVE BACK TO THE NORTH EARLY NEXT
WEEK WITH LESSENING CHANCES OF SHRA/TSTORMS. TEMPS THROUGH THE
PERIOD WILL CONTINUE ABOVE AVERAGE WITH A NOTICEABLE INCREASE IN
HUMIDITY OVER THE COMING DAYS.
&&
.MARINE...EASTERLY WINDS WILL BECOME SE INCREASING WED-THU INTO
THE 15-20 KT RANGE...EVEN OVER THE ATLANTIC ON FRIDAY AS WINDS
BECOME MORE SOUTHERLY WITH THE APPROACH OF A COLD FRONT. TSTORMS
WILL BECOME POSSIBLE BY LATE WEEK, ESPECIALLY OVER THE UPCOMING
WEEKEND.
&&
.FIRE WEATHER...RELATIVE HUMIDITIES WILL REMAIN ABOVE CRITICAL
LEVELS DUE TO INCREASING HUMIDITY ON ESE WINDS BECOMING SE AND
EVENTUALLY SOUTHERLY THIS WEEKEND. THERE WILL BE AN INCREASING
CHANCE OF THUNDERSTORMS BY LATE IN THE WEEK WITH THE CONCERN FOR
WILDFIRES CAUSED BY LIGHTNING STRIKES.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 82 73 82 73 / 10 10 20 20
FORT LAUDERDALE 81 75 83 74 / 10 10 20 20
MIAMI 82 73 84 74 / 10 10 20 20
NAPLES 87 68 88 70 / - - 20 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...57/GREGORIA
AVIATION/RADAR...10/CD
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
954 PM CDT WED APR 10 2013
.MESOSCALE DISCUSSION...
655 PM CDT
A CONTINUED INCREASE IN CONVECTION IS EXPECTED ACROSS CENTRAL IL
PROGRESSING NORTHEAST INTO THE FORECAST AREA...WITH A CHANCE FOR
RAINFALL EXCEEDING FLOOD GUIDANCE IN SOME AREAS...ALONG WITH THE
SLIGHT RISK OF A SEVERE STORM OR TWO...ESPECIALLY ACROSS THE NEW
WATCH AREA.
LATEST HAND SURFACE ANALYSIS INDICATES THE SURFACE BOUNDARY
REMAINS STATIONARY FROM SOUTHWEST IL ENE THROUGH CENTRAL IN. THE
SURFACE LOW IN EAST CENTRAL MO CONTINUES TO EVOLVE NORTHEAST BUT
THE BOUNDARY SHOULD ADVANCE LITTLE NORTHWARD WITH REGENERATING
CONVECTION. WHILE STORMS HAD BEEN MAINLY FOCUSED ALONG THE
BOUNDARY IN CENTRAL IL DURING THE AFTERNOON...THE LAST HOUR TO TWO
HAS SHOWN A TREND FOR MUCH MORE DEVELOPMENT TO THE NORTH OF THAT
AS WARM AND MOIST ADVECTION IN THE LOW-LEVEL JET LAYER INCREASES.
IR IMAGERY CONTINUES TO SHOW COOLING CLOUD TOPS FROM THIS AREA OF
CONVECTION AS WELL AS THE LARGE BATCH IN MO TO FAR WEST CENTRAL
IL.
THIS LOW-LEVEL JET WILL CONTINUE TO INCREASE WITH IMPRESSIVE
MOISTURE TRANSPORT AND REPLENISHMENT ADVANCING NORTHWARD THROUGH
THE EVENING...ESPECIALLY BETWEEN 03Z AND 08Z. SHOWERS AND EMBEDDED
STORMS SHOULD BE PLENTIFUL IN THE CWA DURING THIS TIME. THIS LOW-
LEVEL JET INCREASE WILL ALL BE A RESULT OF MID TO UPPER LEVEL
FORCING AND DIFFLUENCE INCREASING WITH THE UPPER TROUGH ADVANCING
EASTWARD...AND ANOTHER LEAD SHORT WAVE NEAR THE KS/MO BORDER. THIS
SHORT WAVE AND ASSOCIATED 60 KT 700 MB FLOW SHOULD HELP TO SUSTAIN
MORE THAN EFFICIENT SHEAR TO ORGANIZE CONVECTION ON THE LOW-LEVEL
JET NOSE AND ELEVATED THERMAL BOUNDARY ACROSS THE SOUTHERN THIRD
TO HALF OF THE FORECAST AREA. ELEVATED INSTABILITY OF 500-1000
J/KG IS ANALYZED ACROSS THE SOUTH AND ADAPTING AN AMDAR SOUNDING
FOR RAP FORECAST 850 T/TDS AT 03Z INDICATES PARCELS SHOULD BE NEAR
THAT UPPER BOUND IN THE SOUTHERN FORECAST AREA. SOME OF THE
CONVECTIVE ALLOWING GUIDANCE DOES SHOW A FOCUSED CIRCULATION
/ALMOST MCV-LIKE/ ACROSS THE SOUTHERN AREA. WHILE NORTH OF THE
BOUNDARY BY QUITE A DISTANCE...THE EFFECTIVE SHEAR OF 50-70 KT
FORECAST BY THE RAP OVER THE FAR SOUTHERN CWA AND ADJACENT
COUNTIES IS SUFFICIENT FOR POTENTIAL BOWING STRUCTURES ABLE TO
PUSH WIND DOWN. WE DID SEE SOME OF THAT WITH A SIMILAR COMPLEX
THIS MORNING TOWARD ROCHELLE.
THE HEAVY RAIN THREAT CONTINUES WITH NOT ONLY HIGH MOISTURE
VALUES FOR EFFICIENT RAIN PRODUCERS /700 MB DEW POINTS NEAR
4C/...BUT FORECAST STORM MOTION FOR PRECIP TRAINING ALONG THE
ELEVATED STATIONARY BOUNDARY. SUCH BEHAVIOR HAS ALREADY BEEN
OBSERVED WITH SOME OF THE STORMS IN CENTRAL IL. AREAS IN THE FAR
SOUTHEAST DID RECEIVE A RADAR ESTIMATED ONE AND A HALF TO THREE
INCHES OF RAIN EARLIER AND ARE MORE VULNERABLE...WHICH IS WHERE
THE CURRENT FLOOD ADVISORY IS IN EFFECT. WILL BE KEEPING A CLOSE
EYE ON RAINFALL RATES BUT ALL IN ALL FORECAST QPF FROM EARLIER
STILL LOOKS ON TRACK...BASICALLY A WIDESPREAD ONE TO ONE AND A
HALF INCHES TONIGHT...WITH THE ISOLATED HIGHER AMOUNTS NAMELY
SOUTH OF I-80.
MTF
&&
.DISCUSSION...
358 PM CDT
SHORT TERM...LATE THIS AFTERNOON AND TONIGHT...
NEXT SHORT WAVE LIFTING UP THE E SIDE OF THE PLAINS UPPER TROF
IS MOVING NORTHEASTWARD OVER IA AT MID AFTERNOON. AS IT HAS BEEN
APPROACHING A BROAD AREA OF RAIN HAD SPREAD FAR AS SOUTHERN WI
AND N CENTRAL IL WHILE S OF THE SURFACE BOUNDARY...THAT HAD
RETREATED BACK TO CENTRAL IL THIS MORNING...THUNDERSTORMS HAD
BROKEN OUT. WHILE SOME OF THESE THUNDERSTORMS AND HEAVIER SHOWERS
WERE BEING CARRIER NE OVER THE FAR SOUTHERN PORTION OF THE LOCAL
FORECAST AREA BY THE MEAN FLOW THEY QUICKLY BECOME ELEVATED DUE
TO THE VERY STABLE BOUNDARY LAYER IN PLACE N OF SAID BOUNDARY.
DEW POINTS S OF THE BOUNDARY RISE ARE IN THE LOWER AND MID 60S
WITH UPPER 60S FURTHER S. WITH PARTLY CLOUD SKIES OVER ABOUT THE
S HALF OF IL IT HAS BECOME QUITE UNSTABLE DOWNSTATE AS TEMPS HAVE
WARMED. WITH THE SHORT WAVE NOTED ABOVE TO MOVE ESE THEN E OVER
SOUTHERN WI AND FAR NORTHERN IL DURING THE LATE AFTERNOON AND
VERY EARLY EVENING AS IT APPROACHES AND THEN TOPS THE UPPER RIDGE
DOWN STREAM FROM THE CENTRAL U.S. TROF RAIN COVERAGE IS EXPECTED
TO TEMPORARILY DECREASE FOR THE REST OF THE FIRST HALF OF THE
EVENING. THIS SHORT WAVE PASSING BY IS ALSO EXPECTED TO KEEP THE
QUASI-STATIONARY FRONT DOWN ACROSS CENTRAL IL OR EVEN GIVE IT A
SLIGHT NUDGE FURTHER S THIS EVENING.
AS WE GET INTO LATER THIS EVENING AND OVERNIGHT YET ANOTHER SHORT
WAVE...CURRENTLY LIFTING NE FROM FAR NE TX IS TO LIFT TO EASTERN
IA AND NORTHERN IL BY THU MORNING. AS IT MOVES CLOSER LATER
TONIGHT EXPECT ANOTHER BROAD AREA OF RAIN TO DEVELOP AND SPREAD
ACROSS THE FORECAST AREA. WHILE THE LATE AFTERNOON-EARLY EVENING
RAIN IS NOT EXPECTED TO HAVE MUCH IF ANY THUNDERSTORMS ASSOCIATED
WITH IT AS THE BOUNDARY LAYER WILL REMAIN VERY STABLE AND
TEMPERATURE PROFILES ALOFT DO NOT LOOK ESPECIALLY CONDUCIVE TO
UPDRAFT DEVELOPMENT THE RAIN LATER THIS EVENING AND OVERNIGHT WILL
LIKELY HAVE SOME EMBEDDED ELEVATED THUNDERSTORMS AS SOME MINOR
MID LEVEL COOLING OCCURS AS THE UPPER TROF MOVES SLOWLY EASTWARD
DURING THE NIGHT. EVEN WITHOUT CONVECTIVE UPDRAFTS TE OVERALL DEEP
STRONG UPWARD LIFT AS THE MAIN SYSTEM APPROACHES WILL LIKELY
SUPPORT PERIODS OF MODERATE RAIN.
THURSDAY AND FRIDAY...
BY THU MORNING THE UPPER LOW IS PROGGED TO STILL BE OVER THE MID
MO VALLEY WHILE THE ASSOCIATED SURFACE CIRCULATION IS OVER/NEAR
THE LOCAL FORECAST AREA. BY THIS TIME THE BETTER FORCING WILL HAVE
MOVED ON TO OVER WI AND THE WESTERN GREAT LAKES. WITH THE MID AND
UPPER LEVEL LOWS TO THE W AND ONLY GRADUALLY DRIFT E DURING THE
DAY TOMORROW THE THREAT OF ADDITIONAL SHOWERS WILL PERSIST INTO IF
OT THROUGH THU NIGHT BEFORE THE UPPER SYSTEM STARTS TO PULL SLOWLY
AWAY TO THE NE. WHILE MUCH OF THE SOUTHERN AND EASTERN PORTIONS OF
THE FA MAY BRIEFLY GET INTO THE WARM SECTOR AS THE LOW MOVES
ACROSS THE AREA ONCE IT DOES LOW LEVEL COLD AIR ADVECTION GETS
ESTABLISHED AS THE VERY COOL AIR CURRENTLY OVER THE UPPER MIDWEST
AND THE WESTERN GREAT LAKES GETS WRAPPED AROUND THE DEPARTING
SURFACE LOW. OVERNIGHT LOWS THU NIGHT/FRI MORNING LOOK TO BE QUITE
COOL WITH 30S ACROSS THE AREA...AND POSSIBLY GETTING DOWN TO
FREEZING IN THE NORTH CENTRAL WESTERN PART OF THE FA. SOME LIGHT
SHOWERS CANNOT BE RULED OUT WITH COLD CYCLONIC FLOW STILL OVER THE
REGION INTO FRI AS THE UPPER LOW IS VERY SLOW TO MOVE OFF TO THE
NE. THERE MAY EVEN BE SOME LIGHT SNOW SHOWERS DURING THE LATE THU
NIGHT INTO FRI DUE TO THE RELUCTANCE OF THE LOW AND ITS COLD
CYCLONIC LOW IS VERY RELUCTANT TO SPEED AWAY. WITH COLD AIR STILL
IN PLACE AND MOSTLY CLOUDY SKIES FRI MAX TEMPS ARE ONLY EXPECTED
TO BE IN THE LOWER AND MID 40S...WITH SOME UPPER 40S IN THE S
COUNTIES OF THE FA.
SAT AND SUN...
COOL CONDITIONS TO PERSIST SAT AS WE REMAIN UNDER NW FLOW THEN
MODERATING TEMPS FOR SUN AS THE OLD UPPER LOW FINALLY MOVES ACROSS
QUEBEC AND THE FLOW BACKS TO WSW. HOWEVER...ANOTHER UPPER
DISTURBANCE IS PROGGED TO BE MOVING EASTWARD FROM THE NORTHERN
ROCKIES AND NORTHERN HIGH PLAINS. RETURN FLOW WILL BE
INCREASING...RESULTING IN THE MODERATION IN TEMPS...BUT WILL ALSO
BE DRAWING GULF MOISTURE NORTHWARD WITH A THREAT OF RAIN.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 03Z...
* IFR/LIFR CEILINGS INTO THURSDAY.
* POTENTIAL FOR THUNDERSTORMS THIS EVENING/OVERNIGHT.
* GUSTY EAST-NORTHEAST WINDS 25-30 KT OVERNIGHT.
* LIGHT/VARIABLE WINDS NEAR SURFACE FRONT/TROUGH AXIS THURSDAY.
RATZER
//DISCUSSION...UPDATED 00Z...
SURFACE LOW PRESSURE WAS OVER SOUTHEAST MISSOURI EARLY THIS EVENING
WITH A VERY PRONOUNCED WARM FRONT EXTENDING FROM THE LOW ACROSS
SOUTHERN ILLINOIS INTO CENTRAL OHIO. THIS LOW WILL MOVE NORTHEAST
INTO CENTRAL/NORTHERN ILLINOIS AND DEEPEN TONIGHT IN RESPONSE TO A
STRONG MID-LEVEL DISTURBANCE LIFTING NORTHEAST FROM OKLAHOMA/KANSAS.
THE LOW WILL THEN OCCLUDE ACROSS NORTHERN IL ON THURSDAY...WITH THE
LOW AND OCCLUDED WARM FRONTAL TROUGH BECOMING ELONGATED ACROSS THE
FORECAST AREA DURING THE DAY.
NORTH OF THE WARM FRONT...GUSTY NORTHEAST WINDS CONTINUE TO MAINTAIN
MOIST/COOL LOW LEVEL CONDITIONS ACROSS THE FORECAST AREA WITH
EXTENSIVE IFR/LIFR CEILINGS IN PLACE. THESE CONDITIONS ARE EXPECTED
TO REMAIN FAIRLY CONSTANT INTO TONIGHT...WITH NORTHEAST WINDS
GUSTING 25-30 KT AS GRADIENT TIGHTENS IN RESPONSE TO APPROACH AND
DEEPENING OF AFOREMENTIONED SURFACE LOW. IN ADDITION...SHOWERS AND
THUNDERSTORMS CURRENTLY DEVELOPING OVER EASTERN MISSOURI AND WESTERN
IL ARE EXPECTED TO SPREAD NORTHEAST ACROSS THE TERMINALS THIS
EVENING...WITH RAIN HELPING TO MAINTAIN IFR/LIFR CIGS IN COOL
BOUNDARY LAYER. FORECAST SOUNDINGS DEVELOP ELEVATED INSTABILITY
ABOVE THE WARM FRONTAL INVERSION WHICH SHOULD SUPPORT AT LEAST
SCATTERED THUNDERSTORM ACTIVITY AS FAR NORTH AS RFD-ORD AREA... WITH
THE PERIOD OF HIGHEST TS PROBABILITY EXPECTED FROM MID-EVENING
THROUGH AFTER MIDNIGHT. GREATER POTENTIAL FOR THUNDERSTORMS WILL
EXIST ACROSS/SOUTH OF THE I-80 CORRIDOR. ELEVATED INSTABILITY MAY
LINGER ACROSS TERMINALS THROUGH THURSDAY MORNING...THOUGH FORCING
APPEARS TO WEAKEN BEYOND 09Z OR SO THUS HAVE INDICATED TEMPO FOR TS
02-06Z FOR RFD AREA AND 04-08Z IN CHI. SCATTERED SHOWERS WILL LIKELY
LINGER EARLY THURS AM BEFORE PRECIP DIMINISHES/MOVES LARGELY NORTH
AND EAST OF THE FORECAST AREA BETWEEN 12-15Z. SOME SPOTTY SHOWERS
COULD OCCUR DURING THE DAY THOUGH PROBABILITY IS LOW ENOUGH TO LEAVE
OUT OF THE TAFS BEYOND 15Z.
EAST-NORTHEAST WINDS WHICH WILL REMAIN GUSTY 25-30 KT MOST OF THE
NIGHT SHOULD DIMINISH FAIRLY QUICKLY THURSDAY MORNING AS BY THEN
WEAKENING SURFACE LOW AND ELONGATED OCCLUDED FRONTAL TROUGH LIFT
OVER THE FORECAST AREA. GUIDANCE INDICATES THIS FRONTAL TROUGH WILL
LINGER ACROSS A RFD-CHI AXIS DURING THE DAY...MAKING FORECAST OF
DIRECTION OF LIGHT WINDS FAIRLY LOW CONFIDENCE AND ALSO SUGGESTING
THAT IMPROVEMENT OF IFR/LIFR CIGS WILL BE SLOW. HAVE INDICATED A
SLOW DIURNAL IMPROVING TREND IN CIGS DURING THE DAY THURSDAY WITH
WINDS BECOMING LIGHT/VARIABLE...THOUGH IT COULD IMPROVE FASTER IF
FRONT LIFTS SOLIDLY NORTH OF TERMINALS IN THE AFTERNOON. IT APPEARS
HOWEVER THAT STRONGER PUSH OF WEST-SOUTHWEST WINDS AND HIGHER CIGS
WILL BE MORE LIKELY TO DEVELOP THURSDAY EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 03Z...
* HIGH CONFIDENCE IN IFR/LIFR CIGS AND WIND TRENDS OVERNIGHT.
* MEDIUM-HIGH CONFIDENCE IN TIMING/EXTENT OF TSRA.
* LOW CONFIDENCE IN WIND AND CIG HEIGHT DETAILS THURSDAY
MIDDAY/AFTERNOON.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHANCE OF RAIN/SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY...VFR.
SUNDAY THROUGH TUESDAY...PERIODIC CHANCES OF RAIN. OCCASIONAL MVFR
CONDITIONS POSSIBLE.
RATZER
&&
.MARINE...
335 AM...THE GRADIENT REMAINS FAIRLY STRONG ACROSS THE CENTRAL
PORTION OF THE LAKE WITH GALE GUSTS BEING REPORTED ALONG PARTS OF
THE WI SHORE AND MOVED UP THE START TIME OF THE GALE WARNING FOR
THE CENTRAL THIRD TO NOW. AS ELONGATED LOW PRESSURE FROM MISSOURI
SOUTH INTO TEXAS CONSOLIDATES INTO A SMALLER LOW...WHICH WILL MOVE
INTO NORTHERN IL THURSDAY MORNING...THE GRADIENT WILL CONTINUE TO
TIGHTEN WITH HIGH PRESSURE BUILDING ACROSS NORTH CENTRAL ONTARIO.
GALES WILL THEN SPREAD ACROSS THE ENTIRE LAKE AND HAVE UPGRADED
THE GALE WATCH FOR THE SOUTHERN THIRD TO A GALE WARNING STARTING
LATE THIS AFTERNOON. MAY NEED A SHORT DURATION GALE WARNING FOR
THE ILLINOIS NEARSHORE WATERS THIS EVENING/OVERNIGHT AS THE LOW
APPROACHES AND THIS WILL NEED TO BE MONITORED WITH LATER
FORECASTS. THE LOW IS NOW EXPECTED TO ELONGATE ACROSS THE SOUTHERN
LAKES REGION THURSDAY NIGHT. THIS WILL BRING SOUTHERLY WINDS TO
THE SOUTHERN THIRD OF THE LAKE WHILE STRONGER NORTHEASTERLY WINDS
REMAIN OVER THE NORTHERN PORTIONS OF THE LAKE. BY FRIDAY AFTERNOON
THE LOW MOVES EAST OF THE LAKE WITH NORTHWESTERLY FLOW SLOWLY
WEAKENING ON SATURDAY AS HIGH PRESSURE APPROACHES. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10 AM THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741...10 AM THURSDAY TO 11 PM
FRIDAY.
GALE WARNING...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM THURSDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 10 AM FRIDAY.
SMALL CRAFT ADVISORY...LMZ742 UNTIL 11 PM FRIDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 5 AM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
929 PM CDT WED APR 10 2013
.DISCUSSION...
ISSUED 930 PM CDT WED APR 10 2013
MCS CLUSTER CONTINUES TO PUSH ACROSS ILLINOIS SOUTHWARD TO NEAR
MEMPHIS...WITH THE CORE OF THE LINE ABOUT HALFWAY ACROSS THE ILX
FORECAST AREA. SURFACE OBS SHOWING A COUPLE LOWS...ONE JUST WEST
OF EFFINGHAM WHICH MAY BE MORE OF A MESO-LOW...AND THE PRIMARY LOW
JUST WEST OF ST LOUIS. ASSOCIATED SURFACE BOUNDARY WAS ROUGHLY
ALONG I-70 AT 9 PM...WHICH THE MODELS HAVE BEEN STRUGGLING WITH
ITS PLACEMENT UNTIL RECENTLY. HOWEVER...THE LATEST RAP MODEL HAS A
BETTER HANDLE ON IT...AND IS SHOWING A NORTHWARD BULGE BACK TOWARD
CHAMPAIGN AND DANVILLE BY AROUND MIDNIGHT AS THE MAIN LOW MOVES
INTO CENTRAL ILLINOIS. CONTINUING SEVERE THREAT ACROSS AREAS
MAINLY EAST OF I-55 FOR THE NEXT 3 TO 4 HOURS OR SO...THEN RAIN
WILL BE TAPERING FROM THE WEST AFTER MIDNIGHT. TEMPERATURES WILL
STILL BE A CHALLENGE WITH THE SIGNIFICANT TEMPERATURE SHIFTS ALONG
OUR CURRENT BOUNDARY AND THE INCOMING COLD FRONT...BUT THE
SOUTHEAST CWA IS MOST LIKELY TO REMAIN IN THE WARM SECTOR MOST OF
THE NIGHT.
GEELHART
&&
.AVIATION...
ISSUED 652 PM CDT WED APR 10 2013
COMPLEX TAF FORECAST THIS EVENING FOR THE NEXT 12 HOURS WITH
PERIODS OF SHOWERS AND T-STORMS ANTICIPATED IN ASSOCIATION WITH A
LOW IN EAST CENTRAL MO AND A WEST-EAST FRONT EXTENDING ENE NEAR THE I-70
CORRIDOR. NEARLY ALL OF THE TAF SITES HAVE ONGOING T-STORMS WITH A
LINE/SEGMENTS OF STRONG STORMS APPROACHING CENTRAL IL FROM THE MS
RIVER VALLEY AND ANOTHER AREA IN EASTERN MO JUST AHEAD OF A COLD
FRONT THE NEXT FEW HOURS.
CEILINGS ARE EXPECTED TO BE IN THE LOW IFR CATEGORY MUCH OF THE
NIGHT DUE TO THE PROXIMITY OF THE LOW TRACK AND WEST-EAST FRONTAL
BOUNDARY...ALONG WITH T-STORMS IN THE VICINITY ACROSS CENTRAL IL
UNTIL JUST BEFORE DAYBREAK.
THE COLD FRONT WITH THE LOW IS EXPECTED TO REACH THE IL/IN BORDER
AROUND DAYBREAK...ALLOWING THE CEILINGS TO IMPROVE TOWARD MVFR
CIGS THURSDAY MORNING. COULD SEE A FEW SHOWERS FROM PIA-BMI IN THE
LOW LEVEL CYCLONIC FLOW FROM MID-AFTERNOON UNTIL THE END OF THE
TAF PERIOD.
MILLER
&&
.PREV DISCUSSION...
ISSUED 316 PM CDT WED APR 10 2013
ACTIVE WEATHER ONGOING WITH STRONG STORMS IN EXTREME EASTERN IL
AND THUNDERSTORMS IN WEST CENTRAL IL. THE BIGGEST QUESTION FOR
THIS EVENING AND TONIGHT WILL BE THE MOVEMENT OF LOW PRESSURE WEST
OF STL AND THE ASSOCIATED BOUNDARY THAT MOVED THROUGH MUCH OF
CENTRAL IL AND PARTS OF EAST CENTRAL IL THIS MORNING.
TEMPERATURES WILL BE ALL OVER THE PLACE THE NEXT SEVEN DAYS AS
COLDER AIR MOVES IN THE NEXT FEW DAYS...FOLLOWED BY A WARM UP
LATER IN THE WEEK AND THEN A POTENTIAL COOL DOWN AGAIN BY MIDWEEK.
ANOTHER UPPER LEVEL SYSTEM AND ASSOCIATED LOW AND COLD
FRONT...SIMILAR TO THE ONE WE ARE EXPERIENCING TONIGHT-FRIDAY...
IS EXPECTED FROM ABOUT TUESDAY THROUGH MIDWEEK.
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
THERE IS QUITE A BIT OF UNCERTAINTY AS TO THE TRACK OF THE
AFOREMENTIONED SURFACE LOW TONIGHT...WHICH WILL MAKE A HUGE
DIFFERENCE IN TEMPERATURES AND POTENTIAL FOR STRONG/SVR STORMS. AT
THIS POINT IT LOOKS LIKE THE NAM AND LOCAL WRF HAVE THE PREFERRED
SOLUTION WITH THE FRONT CREEPING A LITTLE BIT TO THE NORTH AND THE
LOW TRACKING REAL CLOSE TO SPI AFTER MIDNIGHT AND JUST NORTH OF
CMI-DNV BY DAYBREAK. THIS WOULD KEEP THE BIGGEST THREAT FOR
STRONG/SVR STORMS ROUGHLY ALONG AND EAST OF I-55.
THURSDAY MORNING THE COLD FRONT IS EXPECTED TO BE NEAR THE INDIANA
BORDER...SO WILL KEEP THE MENTION OF T-STORMS GOING IN THE MORNING
IN EASTERN IL...WITH A CHANCE FOR SHOWERS IN WEST CENTRAL IL AND
EAST OF A PIA-DEC-EFFINGHAM LINE THROUGH EARLY EVENING IN THE LOW
LEVEL CYCLONIC FLOW AND SHORTWAVE LIFTING THROUGH THE UPPER
MIDWEST.
CYCLONIC FLOW IS EXPECTED TO REMAIN OVER MUCH OF THE AREA UNTIL
EARLY SATURDAY KEEPING CLOUDS AND COOL TEMPERATURES OVER CENTRAL
AND EASTERN IL. COULD SEE A FEW LIGHT SHOWERS NORTH OF A GBG-PIA-
BMI LINE FRIDAY...OTHERWISE THE REST OF THE FORECAST AREA WILL BE DRY.
LONG TERM...SATURDAY THROUGH WEDNESDAY
HIGH PRESSURE ON SATURDAY WILL GIVE US A BRIEF BREAK IN THE
RAINFALL. HOWEVER...INCREASING WARM ADVECTION IN THE LOW AND MID
LEVELS AND A ZONAL UPPER LEVEL FLOW WILL BRING A RETURN TO SHOWERS
SATURDAY NIGHT...WITH A FEW THUNDERSTORMS POSSIBLE TOWARD SUNDAY
MORNING.
BY EARLY NEXT WEEK OUR UPPER LEVEL PATTERN WILL BACK TO A
SOUTHWEST FLOW AS ANOTHER UPPER LEVEL LOW IS EXPECTED TO DIG INTO
THE SOUTHWESTERN STATES. THE GFS AND EUROPEAN ARE ACTUALLY FAIRLY
SIMILAR IN DEPICTING THIS SCENARIO...ALTHOUGH THE EURO IS A BIT
MORE AMPLIFIED.
THE BIG QUESTION FOR MONDAY THROUGH WEDNESDAY IS WHERE WILL A
NEARLY STATIONARY FRONT SET UP. BOTH THE GFS AND EUROPEAN INDICATE
THAT THE FRONT WILL SETTLE INTO CENTRAL IL MONDAY MORNING AND
REMAIN OVER THE AREA UNTIL AT LEAST TUESDAY. THE GFS IS QUICKER
BRINGING OUT AN AREA OF LOW PRESSURE LATER TUESDAY...WHILE THE
EURO HOLDS OFF UNTIL WEDNESDAY. THE BOTTOM LINE FOR NOW IS THAT
DUE TO THE FRONT IN THE VICINITY WILL NEED TO KEEP AN EXTENDED
PERIOD OF CHANCE POPS IN THE FORECAST FOR MONDAY THROUGH WEDNESDAY.
MILLER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
719 PM CDT WED APR 10 2013
.MESOSCALE DISCUSSION...
655 PM CDT
A CONTINUED INCREASE IN CONVECTION IS EXPECTED ACROSS CENTRAL IL
PROGRESSING NORTHEAST INTO THE FORECAST AREA...WITH A CHANCE FOR
RAINFALL EXCEEDING FLOOD GUIDANCE IN SOME AREAS...ALONG WITH THE
SLIGHT RISK OF A SEVERE STORM OR TWO...ESPECIALLY ACROSS THE NEW
WATCH AREA.
LATEST HAND SURFACE ANALYSIS INDICATES THE SURFACE BOUNDARY
REMAINS STATIONARY FROM SOUTHWEST IL ENE THROUGH CENTRAL IN. THE
SURFACE LOW IN EAST CENTRAL MO CONTINUES TO EVOLVE NORTHEAST BUT
THE BOUNDARY SHOULD ADVANCE LITTLE NORTHWARD WITH REGENERATING
CONVECTION. WHILE STORMS HAD BEEN MAINLY FOCUSED ALONG THE
BOUNDARY IN CENTRAL IL DURING THE AFTERNOON...THE LAST HOUR TO TWO
HAS SHOWN A TREND FOR MUCH MORE DEVELOPMENT TO THE NORTH OF THAT
AS WARM AND MOIST ADVECTION IN THE LOW-LEVEL JET LAYER INCREASES.
IR IMAGERY CONTINUES TO SHOW COOLING CLOUD TOPS FROM THIS AREA OF
CONVECTION AS WELL AS THE LARGE BATCH IN MO TO FAR WEST CENTRAL
IL.
THIS LOW-LEVEL JET WILL CONTINUE TO INCREASE WITH IMPRESSIVE
MOISTURE TRANSPORT AND REPLENISHMENT ADVANCING NORTHWARD THROUGH
THE EVENING...ESPECIALLY BETWEEN 03Z AND 08Z. SHOWERS AND EMBEDDED
STORMS SHOULD BE PLENTIFUL IN THE CWA DURING THIS TIME. THIS LOW-
LEVEL JET INCREASE WILL ALL BE A RESULT OF MID TO UPPER LEVEL
FORCING AND DIFFLUENCE INCREASING WITH THE UPPER TROUGH ADVANCING
EASTWARD...AND ANOTHER LEAD SHORT WAVE NEAR THE KS/MO BORDER. THIS
SHORT WAVE AND ASSOCIATED 60 KT 700 MB FLOW SHOULD HELP TO SUSTAIN
MORE THAN EFFICIENT SHEAR TO ORGANIZE CONVECTION ON THE LOW-LEVEL
JET NOSE AND ELEVATED THERMAL BOUNDARY ACROSS THE SOUTHERN THIRD
TO HALF OF THE FORECAST AREA. ELEVATED INSTABILITY OF 500-1000
J/KG IS ANALYZED ACROSS THE SOUTH AND ADAPTING AN AMDAR SOUNDING
FOR RAP FORECAST 850 T/TDS AT 03Z INDICATES PARCELS SHOULD BE NEAR
THAT UPPER BOUND IN THE SOUTHERN FORECAST AREA. SOME OF THE
CONVECTIVE ALLOWING GUIDANCE DOES SHOW A FOCUSED CIRCULATION
/ALMOST MCV-LIKE/ ACROSS THE SOUTHERN AREA. WHILE NORTH OF THE
BOUNDARY BY QUITE A DISTANCE...THE EFFECTIVE SHEAR OF 50-70 KT
FORECAST BY THE RAP OVER THE FAR SOUTHERN CWA AND ADJACENT
COUNTIES IS SUFFICIENT FOR POTENTIAL BOWING STRUCTURES ABLE TO
PUSH WIND DOWN. WE DID SEE SOME OF THAT WITH A SIMILAR COMPLEX
THIS MORNING TOWARD ROCHELLE.
THE HEAVY RAIN THREAT CONTINUES WITH NOT ONLY HIGH MOISTURE
VALUES FOR EFFICIENT RAIN PRODUCERS /700 MB DEW POINTS NEAR
4C/...BUT FORECAST STORM MOTION FOR PRECIP TRAINING ALONG THE
ELEVATED STATIONARY BOUNDARY. SUCH BEHAVIOR HAS ALREADY BEEN
OBSERVED WITH SOME OF THE STORMS IN CENTRAL IL. AREAS IN THE FAR
SOUTHEAST DID RECEIVE A RADAR ESTIMATED ONE AND A HALF TO THREE
INCHES OF RAIN EARLIER AND ARE MORE VULNERABLE...WHICH IS WHERE
THE CURRENT FLOOD ADVISORY IS IN EFFECT. WILL BE KEEPING A CLOSE
EYE ON RAINFALL RATES BUT ALL IN ALL FORECAST QPF FROM EARLIER
STILL LOOKS ON TRACK...BASICALLY A WIDESPREAD ONE TO ONE AND A
HALF INCHES TONIGHT...WITH THE ISOLATED HIGHER AMOUNTS NAMELY
SOUTH OF I-80.
MTF
&&
.DISCUSSION...
358 PM CDT
SHORT TERM...LATE THIS AFTERNOON AND TONIGHT...
NEXT SHORT WAVE LIFTING UP THE E SIDE OF THE PLAINS UPPER TROF
IS MOVING NORTHEASTWARD OVER IA AT MID AFTERNOON. AS IT HAS BEEN
APPROACHING A BROAD AREA OF RAIN HAD SPREAD FAR AS SOUTHERN WI
AND N CENTRAL IL WHILE S OF THE SURFACE BOUNDARY...THAT HAD
RETREATED BACK TO CENTRAL IL THIS MORNING...THUNDERSTORMS HAD
BROKEN OUT. WHILE SOME OF THESE THUNDERSTORMS AND HEAVIER SHOWERS
WERE BEING CARRIER NE OVER THE FAR SOUTHERN PORTION OF THE LOCAL
FORECAST AREA BY THE MEAN FLOW THEY QUICKLY BECOME ELEVATED DUE
TO THE VERY STABLE BOUNDARY LAYER IN PLACE N OF SAID BOUNDARY.
DEW POINTS S OF THE BOUNDARY RISE ARE IN THE LOWER AND MID 60S
WITH UPPER 60S FURTHER S. WITH PARTLY CLOUD SKIES OVER ABOUT THE
S HALF OF IL IT HAS BECOME QUITE UNSTABLE DOWNSTATE AS TEMPS HAVE
WARMED. WITH THE SHORT WAVE NOTED ABOVE TO MOVE ESE THEN E OVER
SOUTHERN WI AND FAR NORTHERN IL DURING THE LATE AFTERNOON AND
VERY EARLY EVENING AS IT APPROACHES AND THEN TOPS THE UPPER RIDGE
DOWN STREAM FROM THE CENTRAL U.S. TROF RAIN COVERAGE IS EXPECTED
TO TEMPORARILY DECREASE FOR THE REST OF THE FIRST HALF OF THE
EVENING. THIS SHORT WAVE PASSING BY IS ALSO EXPECTED TO KEEP THE
QUASI-STATIONARY FRONT DOWN ACROSS CENTRAL IL OR EVEN GIVE IT A
SLIGHT NUDGE FURTHER S THIS EVENING.
AS WE GET INTO LATER THIS EVENING AND OVERNIGHT YET ANOTHER SHORT
WAVE...CURRENTLY LIFTING NE FROM FAR NE TX IS TO LIFT TO EASTERN
IA AND NORTHERN IL BY THU MORNING. AS IT MOVES CLOSER LATER
TONIGHT EXPECT ANOTHER BROAD AREA OF RAIN TO DEVELOP AND SPREAD
ACROSS THE FORECAST AREA. WHILE THE LATE AFTERNOON-EARLY EVENING
RAIN IS NOT EXPECTED TO HAVE MUCH IF ANY THUNDERSTORMS ASSOCIATED
WITH IT AS THE BOUNDARY LAYER WILL REMAIN VERY STABLE AND
TEMPERATURE PROFILES ALOFT DO NOT LOOK ESPECIALLY CONDUCIVE TO
UPDRAFT DEVELOPMENT THE RAIN LATER THIS EVENING AND OVERNIGHT WILL
LIKELY HAVE SOME EMBEDDED ELEVATED THUNDERSTORMS AS SOME MINOR
MID LEVEL COOLING OCCURS AS THE UPPER TROF MOVES SLOWLY EASTWARD
DURING THE NIGHT. EVEN WITHOUT CONVECTIVE UPDRAFTS TE OVERALL DEEP
STRONG UPWARD LIFT AS THE MAIN SYSTEM APPROACHES WILL LIKELY
SUPPORT PERIODS OF MODERATE RAIN.
THURSDAY AND FRIDAY...
BY THU MORNING THE UPPER LOW IS PROGGED TO STILL BE OVER THE MID
MO VALLEY WHILE THE ASSOCIATED SURFACE CIRCULATION IS OVER/NEAR
THE LOCAL FORECAST AREA. BY THIS TIME THE BETTER FORCING WILL HAVE
MOVED ON TO OVER WI AND THE WESTERN GREAT LAKES. WITH THE MID AND
UPPER LEVEL LOWS TO THE W AND ONLY GRADUALLY DRIFT E DURING THE
DAY TOMORROW THE THREAT OF ADDITIONAL SHOWERS WILL PERSIST INTO IF
OT THROUGH THU NIGHT BEFORE THE UPPER SYSTEM STARTS TO PULL SLOWLY
AWAY TO THE NE. WHILE MUCH OF THE SOUTHERN AND EASTERN PORTIONS OF
THE FA MAY BRIEFLY GET INTO THE WARM SECTOR AS THE LOW MOVES
ACROSS THE AREA ONCE IT DOES LOW LEVEL COLD AIR ADVECTION GETS
ESTABLISHED AS THE VERY COOL AIR CURRENTLY OVER THE UPPER MIDWEST
AND THE WESTERN GREAT LAKES GETS WRAPPED AROUND THE DEPARTING
SURFACE LOW. OVERNIGHT LOWS THU NIGHT/FRI MORNING LOOK TO BE QUITE
COOL WITH 30S ACROSS THE AREA...AND POSSIBLY GETTING DOWN TO
FREEZING IN THE NORTH CENTRAL WESTERN PART OF THE FA. SOME LIGHT
SHOWERS CANNOT BE RULED OUT WITH COLD CYCLONIC FLOW STILL OVER THE
REGION INTO FRI AS THE UPPER LOW IS VERY SLOW TO MOVE OFF TO THE
NE. THERE MAY EVEN BE SOME LIGHT SNOW SHOWERS DURING THE LATE THU
NIGHT INTO FRI DUE TO THE RELUCTANCE OF THE LOW AND ITS COLD
CYCLONIC LOW IS VERY RELUCTANT TO SPEED AWAY. WITH COLD AIR STILL
IN PLACE AND MOSTLY CLOUDY SKIES FRI MAX TEMPS ARE ONLY EXPECTED
TO BE IN THE LOWER AND MID 40S...WITH SOME UPPER 40S IN THE S
COUNTIES OF THE FA.
SAT AND SUN...
COOL CONDITIONS TO PERSIST SAT AS WE REMAIN UNDER NW FLOW THEN
MODERATING TEMPS FOR SUN AS THE OLD UPPER LOW FINALLY MOVES ACROSS
QUEBEC AND THE FLOW BACKS TO WSW. HOWEVER...ANOTHER UPPER
DISTURBANCE IS PROGGED TO BE MOVING EASTWARD FROM THE NORTHERN
ROCKIES AND NORTHERN HIGH PLAINS. RETURN FLOW WILL BE
INCREASING...RESULTING IN THE MODERATION IN TEMPS...BUT WILL ALSO
BE DRAWING GULF MOISTURE NORTHWARD WITH A THREAT OF RAIN.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 00Z...
* IFR/LIFR CEILINGS INTO THURSDAY.
* POTENTIAL FOR THUNDERSTORMS THIS EVENING/OVERNIGHT.
* GUSTY EAST-NORTHEAST WINDS 25-30 KT OVERNIGHT.
* LIGHT/VARIABLE WINDS NEAR SURFACE FRONT/TROUGH AXIS THURSDAY.
RATZER
//DISCUSSION...UPDATED 00Z...
SURFACE LOW PRESSURE WAS OVER SOUTHEAST MISSOURI EARLY THIS EVENING
WITH A VERY PRONOUNCED WARM FRONT EXTENDING FROM THE LOW ACROSS
SOUTHERN ILLINOIS INTO CENTRAL OHIO. THIS LOW WILL MOVE NORTHEAST
INTO CENTRAL/NORTHERN ILLINOIS AND DEEPEN TONIGHT IN RESPONSE TO A
STRONG MID-LEVEL DISTURBANCE LIFTING NORTHEAST FROM OKLAHOMA/KANSAS.
THE LOW WILL THEN OCCLUDE ACROSS NORTHERN IL ON THURSDAY...WITH THE
LOW AND OCCLUDED WARM FRONTAL TROUGH BECOMING ELONGATED ACROSS THE
FORECAST AREA DURING THE DAY.
NORTH OF THE WARM FRONT...GUSTY NORTHEAST WINDS CONTINUE TO MAINTAIN
MOIST/COOL LOW LEVEL CONDITIONS ACROSS THE FORECAST AREA WITH
EXTENSIVE IFR/LIFR CEILINGS IN PLACE. THESE CONDITIONS ARE EXPECTED
TO REMAIN FAIRLY CONSTANT INTO TONIGHT...WITH NORTHEAST WINDS
GUSTING 25-30 KT AS GRADIENT TIGHTENS IN RESPONSE TO APPROACH AND
DEEPENING OF AFOREMENTIONED SURFACE LOW. IN ADDITION...SHOWERS AND
THUNDERSTORMS CURRENTLY DEVELOPING OVER EASTERN MISSOURI AND WESTERN
IL ARE EXPECTED TO SPREAD NORTHEAST ACROSS THE TERMINALS THIS
EVENING...WITH RAIN HELPING TO MAINTAIN IFR/LIFR CIGS IN COOL
BOUNDARY LAYER. FORECAST SOUNDINGS DEVELOP ELEVATED INSTABILITY
ABOVE THE WARM FRONTAL INVERSION WHICH SHOULD SUPPORT AT LEAST
SCATTERED THUNDERSTORM ACTIVITY AS FAR NORTH AS RFD-ORD AREA... WITH
THE PERIOD OF HIGHEST TS PROBABILITY EXPECTED FROM MID-EVENING
THROUGH AFTER MIDNIGHT. GREATER POTENTIAL FOR THUNDERSTORMS WILL
EXIST ACROSS/SOUTH OF THE I-80 CORRIDOR. ELEVATED INSTABILITY MAY
LINGER ACROSS TERMINALS THROUGH THURSDAY MORNING...THOUGH FORCING
APPEARS TO WEAKEN BEYOND 09Z OR SO THUS HAVE INDICATED TEMPO FOR TS
02-06Z FOR RFD AREA AND 04-08Z IN CHI. SCATTERED SHOWERS WILL LIKELY
LINGER EARLY THURS AM BEFORE PRECIP DIMINISHES/MOVES LARGELY NORTH
AND EAST OF THE FORECAST AREA BETWEEN 12-15Z. SOME SPOTTY SHOWERS
COULD OCCUR DURING THE DAY THOUGH PROBABILITY IS LOW ENOUGH TO LEAVE
OUT OF THE TAFS BEYOND 15Z.
EAST-NORTHEAST WINDS WHICH WILL REMAIN GUSTY 25-30 KT MOST OF THE
NIGHT SHOULD DIMINISH FAIRLY QUICKLY THURSDAY MORNING AS BY THEN
WEAKENING SURFACE LOW AND ELONGATED OCCLUDED FRONTAL TROUGH LIFT
OVER THE FORECAST AREA. GUIDANCE INDICATES THIS FRONTAL TROUGH WILL
LINGER ACROSS A RFD-CHI AXIS DURING THE DAY...MAKING FORECAST OF
DIRECTION OF LIGHT WINDS FAIRLY LOW CONFIDENCE AND ALSO SUGGESTING
THAT IMPROVEMENT OF IFR/LIFR CIGS WILL BE SLOW. HAVE INDICATED A
SLOW DIURNAL IMPROVING TREND IN CIGS DURING THE DAY THURSDAY WITH
WINDS BECOMING LIGHT/VARIABLE...THOUGH IT COULD IMPROVE FASTER IF
FRONT LIFTS SOLIDLY NORTH OF TERMINALS IN THE AFTERNOON. IT APPEARS
HOWEVER THAT STRONGER PUSH OF WEST-SOUTHWEST WINDS AND HIGHER CIGS
WILL BE MORE LIKELY TO DEVELOP THURSDAY EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 00Z...
* HIGH CONFIDENCE IN IFR/LIFR CIGS AND WIND TRENDS OVERNIGHT.
* MEDIUM CONFIDENCE IN TIMING/EXTENT OF TSRA.
* LOW CONFIDENCE IN WIND AND CIG HEIGHT DETAILS THURSDAY
MIDDAY/AFTERNOON.
RATZER
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHANCE OF RAIN/SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY...VFR.
SUNDAY THROUGH TUESDAY...PERIODIC CHANCES OF RAIN. OCCASIONAL MVFR
CONDITIONS POSSIBLE.
RATZER
&&
.MARINE...
335 AM...THE GRADIENT REMAINS FAIRLY STRONG ACROSS THE CENTRAL
PORTION OF THE LAKE WITH GALE GUSTS BEING REPORTED ALONG PARTS OF
THE WI SHORE AND MOVED UP THE START TIME OF THE GALE WARNING FOR
THE CENTRAL THIRD TO NOW. AS ELONGATED LOW PRESSURE FROM MISSOURI
SOUTH INTO TEXAS CONSOLIDATES INTO A SMALLER LOW...WHICH WILL MOVE
INTO NORTHERN IL THURSDAY MORNING...THE GRADIENT WILL CONTINUE TO
TIGHTEN WITH HIGH PRESSURE BUILDING ACROSS NORTH CENTRAL ONTARIO.
GALES WILL THEN SPREAD ACROSS THE ENTIRE LAKE AND HAVE UPGRADED
THE GALE WATCH FOR THE SOUTHERN THIRD TO A GALE WARNING STARTING
LATE THIS AFTERNOON. MAY NEED A SHORT DURATION GALE WARNING FOR
THE ILLINOIS NEARSHORE WATERS THIS EVENING/OVERNIGHT AS THE LOW
APPROACHES AND THIS WILL NEED TO BE MONITORED WITH LATER
FORECASTS. THE LOW IS NOW EXPECTED TO ELONGATE ACROSS THE SOUTHERN
LAKES REGION THURSDAY NIGHT. THIS WILL BRING SOUTHERLY WINDS TO
THE SOUTHERN THIRD OF THE LAKE WHILE STRONGER NORTHEASTERLY WINDS
REMAIN OVER THE NORTHERN PORTIONS OF THE LAKE. BY FRIDAY AFTERNOON
THE LOW MOVES EAST OF THE LAKE WITH NORTHWESTERLY FLOW SLOWLY
WEAKENING ON SATURDAY AS HIGH PRESSURE APPROACHES. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM THURSDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 10 AM FRIDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 11 PM FRIDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 5 AM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS CHICAGO/ROMEOVILLE IL
658 PM CDT WED APR 10 2013
.MESOSCALE DISCUSSION...
655 PM CDT
A CONTINUED INCREASE IN CONVECTION IS EXPECTED ACROSS CENTRAL IL
PROGRESSING NORTHEAST INTO THE FORECAST AREA...WITH A CHANCE FOR
RAINFALL EXCEEDING FLOOD GUIDANCE IN SOME AREAS...ALONG WITH THE
SLIGHT RISK OF A SEVERE STORM OR TWO...ESPECIALLY ACROSS THE NEW
WATCH AREA.
LATEST HAND SURFACE ANALYSIS INDICATES THE SURFACE BOUNDARY
REMAINS STATIONARY FROM SOUTHWEST IL ENE THROUGH CENTRAL IN. THE
SURFACE LOW IN EAST CENTRAL MO CONTINUES TO EVOLVE NORTHEAST BUT
THE BOUNDARY SHOULD ADVANCE LITTLE NORTHWARD WITH REGENERATING
CONVECTION. WHILE STORMS HAD BEEN MAINLY FOCUSED ALONG THE
BOUNDARY IN CENTRAL IL DURING THE AFTERNOON...THE LAST HOUR TO TWO
HAS SHOWN A TREND FOR MUCH MORE DEVELOPMENT TO THE NORTH OF THAT
AS WARM AND MOIST ADVECTION IN THE LOW-LEVEL JET LAYER INCREASES.
IR IMAGERY CONTINUES TO SHOW COOLING CLOUD TOPS FROM THIS AREA OF
CONVECTION AS WELL AS THE LARGE BATCH IN MO TO FAR WEST CENTRAL
IL.
THIS LOW-LEVEL JET WILL CONTINUE TO INCREASE WITH IMPRESSIVE
MOISTURE TRANSPORT AND REPLENISHMENT ADVANCING NORTHWARD THROUGH
THE EVENING...ESPECIALLY BETWEEN 03Z AND 08Z. SHOWERS AND EMBEDDED
STORMS SHOULD BE PLENTIFUL IN THE CWA DURING THIS TIME. THIS LOW-
LEVEL JET INCREASE WILL ALL BE A RESULT OF MID TO UPPER LEVEL
FORCING AND DIFFLUENCE INCREASING WITH THE UPPER TROUGH ADVANCING
EASTWARD...AND ANOTHER LEAD SHORT WAVE NEAR THE KS/MO BORDER. THIS
SHORT WAVE AND ASSOCIATED 60 KT 700 MB FLOW SHOULD HELP TO SUSTAIN
MORE THAN EFFICIENT SHEAR TO ORGANIZE CONVECTION ON THE LOW-LEVEL
JET NOSE AND ELEVATED THERMAL BOUNDARY ACROSS THE SOUTHERN THIRD
TO HALF OF THE FORECAST AREA. ELEVATED INSTABILITY OF 500-1000
J/KG IS ANALYZED ACROSS THE SOUTH AND ADAPTING AN AMDAR SOUNDING
FOR RAP FORECAST 850 T/TDS AT 03Z INDICATES PARCELS SHOULD BE NEAR
THAT UPPER BOUND IN THE SOUTHERN FORECAST AREA. SOME OF THE
CONVECTIVE ALLOWING GUIDANCE DOES SHOW A FOCUSED CIRCULATION
/ALMOST MCV-LIKE/ ACROSS THE SOUTHERN AREA. WHILE NORTH OF THE
BOUNDARY BY QUITE A DISTANCE...THE EFFECTIVE SHEAR OF 50-70 KT
FORECAST BY THE RAP OVER THE FAR SOUTHERN CWA AND ADJACENT
COUNTIES IS SUFFICIENT FOR POTENTIAL BOWING STRUCTURES ABLE TO
PUSH WIND DOWN. WE DID SEE SOME OF THAT WITH A SIMILAR COMPLEX
THIS MORNING TOWARD ROCHELLE.
THE HEAVY RAIN THREAT CONTINUES WITH NOT ONLY HIGH MOISTURE
VALUES FOR EFFICIENT RAIN PRODUCERS /700 MB DEW POINTS NEAR
4C/...BUT FORECAST STORM MOTION FOR PRECIP TRAINING ALONG THE
ELEVATED STATIONARY BOUNDARY. SUCH BEHAVIOR HAS ALREADY BEEN
OBSERVED WITH SOME OF THE STORMS IN CENTRAL IL. AREAS IN THE FAR
SOUTHEAST DID RECEIVE A RADAR ESTIMATED ONE AND A HALF TO THREE
INCHES OF RAIN EARLIER AND ARE MORE VULNERABLE...WHICH IS WHERE
THE CURRENT FLOOD ADVISORY IS IN EFFECT. WILL BE KEEPING A CLOSE
EYE ON RAINFALL RATES BUT ALL IN ALL FORECAST QPF FROM EARLIER
STILL LOOKS ON TRACK...BASICALLY A WIDESPREAD ONE TO ONE AND A
HALF INCHES TONIGHT...WITH THE ISOLATED HIGHER AMOUNTS NAMELY
SOUTH OF I-80.
MTF
&&
.DISCUSSION...
358 PM CDT
SHORT TERM...LATE THIS AFTERNOON AND TONIGHT...
NEXT SHORT WAVE LIFTING UP THE E SIDE OF THE PLAINS UPPER TROF
IS MOVING NORTHEASTWARD OVER IA AT MID AFTERNOON. AS IT HAS BEEN
APPROACHING A BROAD AREA OF RAIN HAD SPREAD FAR AS SOUTHERN WI
AND N CENTRAL IL WHILE S OF THE SURFACE BOUNDARY...THAT HAD
RETREATED BACK TO CENTRAL IL THIS MORNING...THUNDERSTORMS HAD
BROKEN OUT. WHILE SOME OF THESE THUNDERSTORMS AND HEAVIER SHOWERS
WERE BEING CARRIER NE OVER THE FAR SOUTHERN PORTION OF THE LOCAL
FORECAST AREA BY THE MEAN FLOW THEY QUICKLY BECOME ELEVATED DUE
TO THE VERY STABLE BOUNDARY LAYER IN PLACE N OF SAID BOUNDARY.
DEW POINTS S OF THE BOUNDARY RISE ARE IN THE LOWER AND MID 60S
WITH UPPER 60S FURTHER S. WITH PARTLY CLOUD SKIES OVER ABOUT THE
S HALF OF IL IT HAS BECOME QUITE UNSTABLE DOWNSTATE AS TEMPS HAVE
WARMED. WITH THE SHORT WAVE NOTED ABOVE TO MOVE ESE THEN E OVER
SOUTHERN WI AND FAR NORTHERN IL DURING THE LATE AFTERNOON AND
VERY EARLY EVENING AS IT APPROACHES AND THEN TOPS THE UPPER RIDGE
DOWN STREAM FROM THE CENTRAL U.S. TROF RAIN COVERAGE IS EXPECTED
TO TEMPORARILY DECREASE FOR THE REST OF THE FIRST HALF OF THE
EVENING. THIS SHORT WAVE PASSING BY IS ALSO EXPECTED TO KEEP THE
QUASI-STATIONARY FRONT DOWN ACROSS CENTRAL IL OR EVEN GIVE IT A
SLIGHT NUDGE FURTHER S THIS EVENING.
AS WE GET INTO LATER THIS EVENING AND OVERNIGHT YET ANOTHER SHORT
WAVE...CURRENTLY LIFTING NE FROM FAR NE TX IS TO LIFT TO EASTERN
IA AND NORTHERN IL BY THU MORNING. AS IT MOVES CLOSER LATER
TONIGHT EXPECT ANOTHER BROAD AREA OF RAIN TO DEVELOP AND SPREAD
ACROSS THE FORECAST AREA. WHILE THE LATE AFTERNOON-EARLY EVENING
RAIN IS NOT EXPECTED TO HAVE MUCH IF ANY THUNDERSTORMS ASSOCIATED
WITH IT AS THE BOUNDARY LAYER WILL REMAIN VERY STABLE AND
TEMPERATURE PROFILES ALOFT DO NOT LOOK ESPECIALLY CONDUCIVE TO
UPDRAFT DEVELOPMENT THE RAIN LATER THIS EVENING AND OVERNIGHT WILL
LIKELY HAVE SOME EMBEDDED ELEVATED THUNDERSTORMS AS SOME MINOR
MID LEVEL COOLING OCCURS AS THE UPPER TROF MOVES SLOWLY EASTWARD
DURING THE NIGHT. EVEN WITHOUT CONVECTIVE UPDRAFTS TE OVERALL DEEP
STRONG UPWARD LIFT AS THE MAIN SYSTEM APPROACHES WILL LIKELY
SUPPORT PERIODS OF MODERATE RAIN.
THURSDAY AND FRIDAY...
BY THU MORNING THE UPPER LOW IS PROGGED TO STILL BE OVER THE MID
MO VALLEY WHILE THE ASSOCIATED SURFACE CIRCULATION IS OVER/NEAR
THE LOCAL FORECAST AREA. BY THIS TIME THE BETTER FORCING WILL HAVE
MOVED ON TO OVER WI AND THE WESTERN GREAT LAKES. WITH THE MID AND
UPPER LEVEL LOWS TO THE W AND ONLY GRADUALLY DRIFT E DURING THE
DAY TOMORROW THE THREAT OF ADDITIONAL SHOWERS WILL PERSIST INTO IF
OT THROUGH THU NIGHT BEFORE THE UPPER SYSTEM STARTS TO PULL SLOWLY
AWAY TO THE NE. WHILE MUCH OF THE SOUTHERN AND EASTERN PORTIONS OF
THE FA MAY BRIEFLY GET INTO THE WARM SECTOR AS THE LOW MOVES
ACROSS THE AREA ONCE IT DOES LOW LEVEL COLD AIR ADVECTION GETS
ESTABLISHED AS THE VERY COOL AIR CURRENTLY OVER THE UPPER MIDWEST
AND THE WESTERN GREAT LAKES GETS WRAPPED AROUND THE DEPARTING
SURFACE LOW. OVERNIGHT LOWS THU NIGHT/FRI MORNING LOOK TO BE QUITE
COOL WITH 30S ACROSS THE AREA...AND POSSIBLY GETTING DOWN TO
FREEZING IN THE NORTH CENTRAL WESTERN PART OF THE FA. SOME LIGHT
SHOWERS CANNOT BE RULED OUT WITH COLD CYCLONIC FLOW STILL OVER THE
REGION INTO FRI AS THE UPPER LOW IS VERY SLOW TO MOVE OFF TO THE
NE. THERE MAY EVEN BE SOME LIGHT SNOW SHOWERS DURING THE LATE THU
NIGHT INTO FRI DUE TO THE RELUCTANCE OF THE LOW AND ITS COLD
CYCLONIC LOW IS VERY RELUCTANT TO SPEED AWAY. WITH COLD AIR STILL
IN PLACE AND MOSTLY CLOUDY SKIES FRI MAX TEMPS ARE ONLY EXPECTED
TO BE IN THE LOWER AND MID 40S...WITH SOME UPPER 40S IN THE S
COUNTIES OF THE FA.
SAT AND SUN...
COOL CONDITIONS TO PERSIST SAT AS WE REMAIN UNDER NW FLOW THEN
MODERATING TEMPS FOR SUN AS THE OLD UPPER LOW FINALLY MOVES ACROSS
QUEBEC AND THE FLOW BACKS TO WSW. HOWEVER...ANOTHER UPPER
DISTURBANCE IS PROGGED TO BE MOVING EASTWARD FROM THE NORTHERN
ROCKIES AND NORTHERN HIGH PLAINS. RETURN FLOW WILL BE
INCREASING...RESULTING IN THE MODERATION IN TEMPS...BUT WILL ALSO
BE DRAWING GULF MOISTURE NORTHWARD WITH A THREAT OF RAIN.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 22Z...
* PERIODS OF SHOWERS THROUGH THE REMAINDER OF THE AFTERNOON.
SHOWERS AND THUNDERSTORMS INCREASING IN NUMBER AND INTENSITY
THIS EVENING AND INTO THE OVERNIGHT HOURS.
* IFR CEILINGS PREVAILING THROUGH THE NIGHT...LIFR POSSIBLE.
* STRONG/GUSTY NORTHEAST WINDS THROUGH MUCH OF TONIGHT.
PAW/RATZER
//DISCUSSION...UPDATED 18Z...
A SURFACE FRONT HAS BEEN NEARLY STATIONARY ACROSS CENTRAL ILLINOIS
THROUGH NORTHEAST INDIANA TODAY. THE TERMINALS ARE ALL ON THE COLD
SIDE OF THIS FRONT IN A LARGE AREA OF IFR CEILINGS. LITTLE
IMPROVEMENT IS EXPECTED UNTIL THE FRONT BEGINS MOVING TO THE NORTH
ON THURSDAY. MEANWHILE...A WAVE MOVING ALONG THE FRONT WILL PUSH
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS INTO THE TERMINALS THIS
AFTERNOON AND EVENING.
PAW
//ORD AND MDW CONFIDENCE...UPDATED 22Z...
* HIGH CONFIDENCE IN SHOWER/THUNDERSTORM TREND...MEDIUM CONFIDENCE
IN DETAILS.
* HIGH CONFIDENCE IN IFR CEILINGS.
* MEDIUM CONFIDENCE IN WIND TREND AND DETAILS.
PAW/RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z FRIDAY-12Z WEDNESDAY...UPDATED 12Z...
* THURSDAY NIGHT AND FRIDAY...CHANCE OF RAIN/SNOW SHOWERS. MVFR
POSSIBLE.
* SATURDAY...DRY/VFR.
* SUNDAY...CHANCE OF SHRA/TSRA. MVFR POSSIBLE.
* MONDAY AND TUESDAY...CHANCE OF SHOWERS. MVFR POSSIBLE.
&&
.MARINE...
335 AM...THE GRADIENT REMAINS FAIRLY STRONG ACROSS THE CENTRAL
PORTION OF THE LAKE WITH GALE GUSTS BEING REPORTED ALONG PARTS OF
THE WI SHORE AND MOVED UP THE START TIME OF THE GALE WARNING FOR
THE CENTRAL THIRD TO NOW. AS ELONGATED LOW PRESSURE FROM MISSOURI
SOUTH INTO TEXAS CONSOLIDATES INTO A SMALLER LOW...WHICH WILL MOVE
INTO NORTHERN IL THURSDAY MORNING...THE GRADIENT WILL CONTINUE TO
TIGHTEN WITH HIGH PRESSURE BUILDING ACROSS NORTH CENTRAL ONTARIO.
GALES WILL THEN SPREAD ACROSS THE ENTIRE LAKE AND HAVE UPGRADED
THE GALE WATCH FOR THE SOUTHERN THIRD TO A GALE WARNING STARTING
LATE THIS AFTERNOON. MAY NEED A SHORT DURATION GALE WARNING FOR
THE ILLINOIS NEARSHORE WATERS THIS EVENING/OVERNIGHT AS THE LOW
APPROACHES AND THIS WILL NEED TO BE MONITORED WITH LATER
FORECASTS. THE LOW IS NOW EXPECTED TO ELONGATE ACROSS THE SOUTHERN
LAKES REGION THURSDAY NIGHT. THIS WILL BRING SOUTHERLY WINDS TO
THE SOUTHERN THIRD OF THE LAKE WHILE STRONGER NORTHEASTERLY WINDS
REMAIN OVER THE NORTHERN PORTIONS OF THE LAKE. BY FRIDAY AFTERNOON
THE LOW MOVES EAST OF THE LAKE WITH NORTHWESTERLY FLOW SLOWLY
WEAKENING ON SATURDAY AS HIGH PRESSURE APPROACHES. CMS
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM THURSDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 10 AM FRIDAY.
SMALL CRAFT ADVISORY...ILLINOIS NEARSHORE WATERS UNTIL 11 PM FRIDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 5 AM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
608 PM CDT WED APR 10 2013
...UPDATED AVIATION DISCUSSION...
.SYNOPSIS...
ISSUED AT 1249 PM CDT WED APR 10 2013
UPPER AIR ANALYSIS ALONG WITH WATER VAPOR IMAGERY REVEALED A LARGE
SCALE TROUGH CENTERED FROM WESTERN SOUTH DAKOTA THROUGH EASTERN
COLORADO/WESTERN KANSAS SOUTHWEST TO SOUTHERN NEW MEXICO. TWO
BAROCLINIC ZONES OF SIGNIFICANCE COULD BE IDENTIFIED FROM 700MB DOWN
TO THE SURFACE THIS MORNING. AT 850MB...THE SOUTHERNMOST FRONT
EXTENDED FROM NORTHWESTERN MISSOURI TO NORTH TEXAS THROUGH DEL RIO
AND INTO MEXICO. THIS FRONT SEPARATED THE WARM, MOIST
MARITIME-TROPICAL (MT) AIRMASS FROM A COOLER CONTINENTAL-POLAR (CP)
AIRMASS. A SECOND FROM SEPARATED THE CP AIRMASS FROM AN EVEN COLDER
CONTINENTAL-ARCTIC TYPE AIRMASS (CA). 850MB TEMPERATURES IN THE CA
AIRMASS WERE VERY ANOMALOUS ON THE COLD SIDE INCLUDING -11C AT
AMARILLO, -9C AT DODGE CITY, AND -13C AT NORTH PLATTE ON THE HIGH
PLAINS. PRECIPITATION THIS MORNING WAS CONFINED MAINLY TO THE
FRONTAL ZONE IN THE 850-700MB LAYER WHERE WINTER PRECIPITATION WAS
OBSERVED FROM CENTRAL KANSAS DOWN INTO WESTERN OKLAHOMA. FREEZING
RAIN WAS EVEN OBSERVED LATE THIS MORNING AND MIDDAY IN OKLAHOMA CITY!
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 337 PM CDT WED APR 10 2013
THE PRIMARY CHALLENGE IN THE FORECAST FOR TONIGHT AND THURSDAY WILL
CENTER AROUND TEMPERATURES. THE 500MB TROUGH AXIS WILL MOVE SLOWLY
ACROSS THE CENTRAL PLAINS TONIGHT AND THURSDAY. A MID LEVEL CYCLONE
WILL MATURE OVERNIGHT IN THE 700-500MB LAYER TO OUR NORTHEAST. THIS
WILL KEEP A HEIGHT GRADIENT IN THE LOWER-MID TROPOSPHERE ACROSS
WESTERN KANSAS...WHICH WILL IN TURN ALLOW SURFACE WINDS TO STAY UP
IN THE 12 TO 15 KNOTS THROUGH MOST OF THE NIGHT TONIGHT AND THROUGH
THE DAY THURSDAY. AS FAR AS TEMPERATURES GO TONIGHT...THE
AFOREMENTIONED WIND SPEED SHOULD ALLOW TEMPERATURES TO TO FALL ONLY
SLOWLY THROUGH THE UPPER 20S TONIGHT...BOTTOMING OUT IN THE LOWER TO
MID 20S. A FEW LOWS IN THE UPPER TEENS ARE FORECAST IN THE
TRADITIONAL COLDER AREAS OF THE FORECAST AREA FROM JOHNSON TO SCOTT
CITY AND POINTS WEST.
TEMPERATURES TOMORROW ARE A LITTLE TRICKY WITH AN 850MB TEMPERATURE
GRADIENT ACROSS WESTERN KANSAS THROUGH THE DAY. WHILE AN 850MB
TEMPERATURE GRADIENT WILL EXIST...THE LOWER TROPOSPHERIC FLOW WILL
HAVE DOWNSLOPE COMPONENT TO HELP DESTROY THE RESULTING GRADIENT AT
THE SURFACE...TO SOME EXTENT. DOWNSLOPE EFFECTS WILL BE MOST
NOTABLE ACROSS FAR SOUTHWEST KANSAS...ESPECIALLY SOUTHWEST OF
DIGHTON TO MEADE LINE...AND THIS IS WHERE WE WILL FORECAST
TEMPERATURES IN THE LOWER TO MID 50S FOR HIGHS. UP AROUND HAYS
THOUGH...WHERE DOWNSLOPE EFFECTS ARE LESS...TEMPERATURES WILL
STRUGGLE TO GET MUCH ABOVE 40 DEGREES.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 337 PM CDT WED APR 10 2013
FRIDAY/SATURDAY:
A MINOR WAVE MOVING ACROSS WESTERN KANSAS IN THE NORTHWESTERLY FLOW
ALOFT MAY HELP TO PRODUCE LIGHT SHOWERS ACROSS FAR WESTERN KANSAS
FRIDAY MORNING. BETTER CONFIDENCE OF MORE WIDESPREAD (ALTHOUGH
LIGHT) PRECIPITATION IS EXPECTED SATURDAY AS A WEAK WARM AIR
ADVECTION PATTERN DEVELOPS. MAXIMUM TEMPERATURES WILL MODERATE
THROUGH THIS PERIOD WITH 50S DEG F ON FRIDAY AND 60S AND 70S DEG F
ON SATURDAY. MINIMUM TEMPERATURES WILL ALSO MODERATE WITH 20S AND
30S DEG F FRIDAY MORNING TO MOSTLY 30S DEG F SATURDAY MORNING.
SUNDAY AND BEYOND:
BY SUNDAY, A STRONG 250 HPA JET WILL EMERGE FROM THE PACIFIC
NORTHWEST OUT TO THE CENTRAL ROCKIES. THIS FEATURE WILL HELP TO
USHER IN THE PASSAGE OF A COLD FRONT ACROSS THE CENTRAL PLAINS
THROUGH LATE SUNDAY. THERE COULD BE A TIGHT TEMPERATURE GRADIENT
ACROSS THE REGION, HOWEVER, THE TIMING OF THE FRONT IS IN QUESTION.
RIGHT NOW WILL GO WITH 60S UP NORTH TO AROUND 80 DOWN SOUTH. THERE
COULD BE SOME LIGHT SHOWERS ACROSS THE NORTHEASTERN ZONES ASSOCIATED
WITH LOW TO MID LEVEL FRONTOGENESIS. FOR THE REST OF THE PD, THE
ECMWF KEEPS THE REGION IN THE COOL SECTOR WITH A FRONT SOUTH OF THE
AREA. TEMPERATURE FORECASTS ARE OF LOW CONFIDENCE AT THIS POINT DUE
TO THE DIFFERENCES BETWEEN THE GFS/ECMWF. THE COOLEST PERIOD LOOKS
TO BE IN ABOUT A WEEK FROM NOW AS NORTHEASTERLY FLOW DEVELOPS ACROSS
SW KANSAS. THERE COULD BE A FEW SHOWERS DURING THIS PERIOD, BUT
NOTHING SIGNIFICANT AS THE WARM SECTOR AND BOUNDARY LAYER MOISTURE
IS WELL TO THE SOUTHEAST. BEYOND WEDNESDAY, THE ECMWF MOVES A LARGE
UPPER LEVEL TROF ACROSS THE NORTHERN PLAINS WITH COOL HIGH PRESSURE
CONTINUING ACROSS KANSAS.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 605 PM CDT WED APR 10 2013
AN AREA OF 925-850MB MOISTURE IS FORECAST BY THE RAP AND NAM TO
MOVE INTO PORTIONS OF SOUTHWEST KANSAS BRIEFLY EARLY TONIGHT AS AN
UPPER LEVEL LOW CROSSES THE CENTRAL HIGH PLAINS. BOTH MODELS ARE
IN DECENT AGREEMENT WITH THIS LOW LEVEL MOISTURE STARTING TO ERODE
FROM WEST TO EAST AFTER 06Z AS ISENTROPIC DOWNGLIDE DEVELOPS.
HAYS STILL IS EXPECTED TO BE IN THE STATUS UNTIL NEAR 12Z BASED ON
THE 18Z NAM. GIVEN THIS AND THE CURRENT CIGS AT HAYS AS OF 23Z
WILL FAVOR MVFR CIGS CONTINUING OVERNIGHT AT HAYS. A PERIOD OF
MVFR CIGS POSSIBLE AT DDC BETWEEN 03Z AND 09Z. GUSTY NORTHWEST
WINDS WILL DECREASE OVERNIGHT INTO THE 10 TO 15KT RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 22 49 29 58 / 10 0 10 20
GCK 21 51 30 59 / 0 0 10 20
EHA 23 55 36 59 / 0 0 20 20
LBL 23 55 34 59 / 0 0 10 20
HYS 22 43 25 55 / 10 0 10 10
P28 25 48 31 58 / 10 0 10 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...UMSCHEID
SHORT TERM...UMSCHEID
LONG TERM...SUGDEN
AVIATION...BURGERT
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
1229 PM CDT TUE APR 9 2013
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 231 AM CDT TUE APR 9
2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 600 AM CDT TUE APR 9 2013
MEDIUM RANGE MODELS INDICATE A STRONG UPPER LEVEL TROUGH OF LOW
PRESSURE DRIFTING SLOWLY EASTWARD ACROSS THE CENTRAL AND SOUTH
PLAINS WEDNESDAY. THIS SYSTEM WILL BRING WIDESPREAD PRECIP FROM
THE GREAT LAKES REGION SOUTHWESTWARD THROUGH EASTERN KANSAS INTO
NORTH TEXAS. HOWEVER, DRIER CONDITIONS ARE EXPECTED ACROSS WESTERN
KANSAS DUE TO A LACK OF LOW LEVEL MOISTURE AND A WEAK FLOW ALOFT.
THE QUIET CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST FRIDAY
AS THE FLOW ALOFT BECOMES MORE WESTERLY AND THE MOISTURE CLOSER TO
THE SURFACE IS SLOW TO RETURN TO WESTERN KANSAS. A SMALL UPPER
LEVEL SHORTWAVE IS PROJECTED TO TRACK EAST-SOUTHEAST ACROSS THE
INTERMOUNTAIN WEST FRIDAY POSSIBLY SETTING UP A CHANCE FOR PRECIP
FOR PORTIONS OF SOUTHWEST KANSAS FRIDAY NIGHT. HOWEVER, TIMING AND
THE PATH OF THE SHORTWAVE REMAIN UNCERTAIN ALONG WITH THE STRENGTH
OF THE SYSTEM ITSELF. WILL RETAIN A SLIGHT CHANCE FOR SHOWERS
ACROSS MUCH OF SOUTHWEST KANSAS FRIDAY NIGHT.
TEMPERATURES WILL BE WELL BELOW NORMAL WEDNESDAY AS MUCH COLDER AIR
CONTINUES TO SURGE SOUTHWARD INTO WESTERN KANSAS. THE NAM, GFS, AND
ECMWF SHOW H85 TEMPERATURES FALLING BELOW 5C BELOW ZERO ACROSS WEST
CENTRAL KANSAS EASTWARD INTO CENTRAL KANSAS, INCLUDING THE I-70
CORRIDOR. THE RELATIVELY WARMER H85 TEMPERATURES WILL BE IN EXTREME
SOUTHWEST KANSAS, YET STILL JUST BELOW 0C. HIGHS WILL ONLY BE IN THE
30S(F) ACROSS MUCH OF CENTRAL AND WESTERN KANSAS WITH NEAR 40F
POSSIBLE NEAR AND ALONG THE OKLAHOMA BORDER. A GRADUAL WARMING TREND
WILL ENSUE THURSDAY WITH HIGHS BACK UP INTO THE 40S(F) AND 50S(F)
WITH THE COOLEST TEMPERATURES IN CENTRAL KANSAS. THE TREND WILL
CONTINUE INTO THE WEEKEND AS THE FLOW ALOFT BECOME MORE ZONAL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1229 PM CDT TUE APR 9 2013
GUSTY NORTH WINDS AT AROUND 25 TO 35 KNOTS WILL CONTINUE THROUGH
THE AFTERNOON HOURS. THE WINDS SHOULD DIMINISH SOMEWHAT WITH
SUNSET BUT WILL CONTINUE TO BE GUSTY. LIGHT FREEZING DRIZZLE WILL
BE POSSIBLE AT THE TAF SITES THIS AFTERNOON. AFTER 00Z, FREEZING
RAIN WILL BE POSSIBLE WHICH SHOULD BE CHANGING OVER TO LIGHT SNOW
LATER TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 49 19 36 23 / 30 30 10 0
GCK 36 17 34 23 / 30 30 0 0
EHA 32 17 37 24 / 30 20 0 0
LBL 39 18 36 24 / 20 20 0 0
HYS 45 19 36 24 / 40 50 10 0
P28 67 25 43 27 / 40 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR KSZ030-
031-043>046-061>065-074>080-084>089.
&&
$$
SHORT TERM...BURKE
LONG TERM...JJOHNSON
AVIATION...GERARD
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
648 AM CDT TUE APR 9 2013
...UPDATE TO AVIATION...
.SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 231 AM CDT TUE APR 9
2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 600 AM CDT TUE APR 9 2013
MEDIUM RANGE MODELS INDICATE A STRONG UPPER LEVEL TROUGH OF LOW
PRESSURE DRIFTING SLOWLY EASTWARD ACROSS THE CENTRAL AND SOUTH
PLAINS WEDNESDAY. THIS SYSTEM WILL BRING WIDESPREAD PRECIP FROM
THE GREAT LAKES REGION SOUTHWESTWARD THROUGH EASTERN KANSAS INTO
NORTH TEXAS. HOWEVER, DRIER CONDITIONS ARE EXPECTED ACROSS WESTERN
KANSAS DUE TO A LACK OF LOW LEVEL MOISTURE AND A WEAK FLOW ALOFT.
THE QUIET CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST FRIDAY
AS THE FLOW ALOFT BECOMES MORE WESTERLY AND THE MOISTURE CLOSER TO
THE SURFACE IS SLOW TO RETURN TO WESTERN KANSAS. A SMALL UPPER
LEVEL SHORTWAVE IS PROJECTED TO TRACK EAST-SOUTHEAST ACROSS THE
INTERMOUNTAIN WEST FRIDAY POSSIBLY SETTING UP A CHANCE FOR PRECIP
FOR PORTIONS OF SOUTHWEST KANSAS FRIDAY NIGHT. HOWEVER, TIMING AND
THE PATH OF THE SHORTWAVE REMAIN UNCERTAIN ALONG WITH THE STRENGTH
OF THE SYSTEM ITSELF. WILL RETAIN A SLIGHT CHANCE FOR SHOWERS
ACROSS MUCH OF SOUTHWEST KANSAS FRIDAY NIGHT.
TEMPERATURES WILL BE WELL BELOW NORMAL WEDNESDAY AS MUCH COLDER AIR
CONTINUES TO SURGE SOUTHWARD INTO WESTERN KANSAS. THE NAM, GFS, AND
ECMWF SHOW H85 TEMPERATURES FALLING BELOW 5C BELOW ZERO ACROSS WEST
CENTRAL KANSAS EASTWARD INTO CENTRAL KANSAS, INCLUDING THE I-70
CORRIDOR. THE RELATIVELY WARMER H85 TEMPERATURES WILL BE IN EXTREME
SOUTHWEST KANSAS, YET STILL JUST BELOW 0C. HIGHS WILL ONLY BE IN THE
30S(F) ACROSS MUCH OF CENTRAL AND WESTERN KANSAS WITH NEAR 40F
POSSIBLE NEAR AND ALONG THE OKLAHOMA BORDER. A GRADUAL WARMING TREND
WILL ENSUE THURSDAY WITH HIGHS BACK UP INTO THE 40S(F) AND 50S(F)
WITH THE COOLEST TEMPERATURES IN CENTRAL KANSAS. THE TREND WILL
CONTINUE INTO THE WEEKEND AS THE FLOW ALOFT BECOME MORE ZONAL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 645 AM CDT TUE APR 9 2013
LOW LEVEL STRATUS WILL CONTINUE TO DEVELOP ALONG AND BEHIND A
STRONG COLD FRONT PUSHING SOUTHEAST ACROSS CENTRAL AND SOUTHWEST
KANSAS EARLY THIS MORNING. PRIMARILY MVFR CIGS WILL PREVAIL AT
ALL TAF SITES THROUGH THIS AFTERNOON WITH BRIEF PERIODS OF IFR
CIGS POSSIBLE EARLY THIS MORNING. LIGHT SNOW WILL THEN BE POSSIBLE
LATE THIS AFTERNOON AND EVENING AS MUCH COLDER AIR SURGES SOUTH
INTO WESTERN KANSAS. STRONG NORTH WINDS WILL DEVELOP BEHIND THE
FRONT AS IT PUSHES THROUGH EARLY THIS MORNING. WIND SPEEDS MAY
REACH UPWARDS OF 30 TO 40KT WITH GUSTS UP TO 45KT INITIALLY BEHIND
THE FRONT. THE NORTH WINDS WILL GRADUALLY SUBSIDE TO AROUND 20 TO
35KT THIS AFTERNOON, THEN CONTINUE TO SLOWLY DECREASE IN SPEED
TONIGHT.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 57 19 36 23 / 30 30 10 0
GCK 45 17 34 23 / 30 30 0 0
EHA 40 17 37 24 / 20 20 0 0
LBL 48 18 36 24 / 20 20 0 0
HYS 49 19 36 24 / 40 50 10 0
P28 70 25 43 27 / 40 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR KSZ030-
031-043>046-061>065-074>080-084>089.
&&
$$
SHORT TERM...BURKE
LONG TERM...JJOHNSON
AVIATION...JJOHNSON
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
610 AM CDT TUE APR 9 2013
...UPDATE TO LONG TERM...
.SYNOPSIS...
ISSUED AT 340 PM CDT MON APR 8 2013
THE 12Z UPPER AIR ANALYSIS SHOWED INCREASING SOUTHWESTERLY FLOW OVER
THE CENTRAL HIGH PLAINS. THIS WAS AHEAD OF AN UPPER TROUGH THAT WAS
DIGGING SOUTHWARD THROUGH THE WESTERN STATES WITH THE HELP OF A 130
KNOT JET AT 250 MB JUST OFF THE OR/WA COAST. AT THE SURFACE, LOW
PRESSURE WAS DEEPENING OVER EASTERN COLORADO. A WARM FRONT EXTENDED
FROM THE LOW ACROSS THE OKLAHOMA PANHANDLE INTO NORTHERN OKLAHOMA.
SURFACE DEWPOINTS HAVE BEEN INCREASING OVER THE CENTRAL AND SOUTHERN
PLAINS OVER THE WEEKEND WITH DEWPOINTS IN THE UPPER 50S/LOW 60S OVER
CENTRAL KANSAS WITH UPPER 40 TO MID 50 DEWPOINTS PUSHING BACK INTO
THE WESTERN HIGH PLAINS TO THE NORTH OF THE WARM FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT TUE APR 9 2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 600 AM CDT TUE APR 9 2013
MEDIUM RANGE MODELS INDICATE A STRONG UPPER LEVEL TROUGH OF LOW
PRESSURE DRIFTING SLOWLY EASTWARD ACROSS THE CENTRAL AND SOUTH
PLAINS WEDNESDAY. THIS SYSTEM WILL BRING WIDESPREAD PRECIP FROM
THE GREAT LAKES REGION SOUTHWESTWARD THROUGH EASTERN KANSAS INTO
NORTH TEXAS. HOWEVER, DRIER CONDITIONS ARE EXPECTED ACROSS WESTERN
KANSAS DUE TO A LACK OF LOW LEVEL MOISTURE AND A WEAK FLOW ALOFT.
THE QUIET CONDITIONS WILL LIKELY CONTINUE THROUGH AT LEAST FRIDAY
AS THE FLOW ALOFT BECOMES MORE WESTERLY AND THE MOISTURE CLOSER TO
THE SURFACE IS SLOW TO RETURN TO WESTERN KANSAS. A SMALL UPPER
LEVEL SHORTWAVE IS PROJECTED TO TRACK EAST-SOUTHEAST ACROSS THE
INTERMOUNTAIN WEST FRIDAY POSSIBLY SETTING UP A CHANCE FOR PRECIP
FOR PORTIONS OF SOUTHWEST KANSAS FRIDAY NIGHT. HOWEVER, TIMING AND
THE PATH OF THE SHORTWAVE REMAIN UNCERTAIN ALONG WITH THE STRENGTH
OF THE SYSTEM ITSELF. WILL RETAIN A SLIGHT CHANCE FOR SHOWERS
ACROSS MUCH OF SOUTHWEST KANSAS FRIDAY NIGHT.
TEMPERATURES WILL BE WELL BELOW NORMAL WEDNESDAY AS MUCH COLDER AIR
CONTINUES TO SURGE SOUTHWARD INTO WESTERN KANSAS. THE NAM, GFS, AND
ECMWF SHOW H85 TEMPERATURES FALLING BELOW 5C BELOW ZERO ACROSS WEST
CENTRAL KANSAS EASTWARD INTO CENTRAL KANSAS, INCLUDING THE I-70
CORRIDOR. THE RELATIVELY WARMER H85 TEMPERATURES WILL BE IN EXTREME
SOUTHWEST KANSAS, YET STILL JUST BELOW 0C. HIGHS WILL ONLY BE IN THE
30S(F) ACROSS MUCH OF CENTRAL AND WESTERN KANSAS WITH NEAR 40F
POSSIBLE NEAR AND ALONG THE OKLAHOMA BORDER. A GRADUAL WARMING TREND
WILL ENSUE THURSDAY WITH HIGHS BACK UP INTO THE 40S(F) AND 50S(F)
WITH THE COOLEST TEMPERATURES IN CENTRAL KANSAS. THE TREND WILL
CONTINUE INTO THE WEEKEND AS THE FLOW ALOFT BECOME MORE ZONAL.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM CDT TUE APR 9 2013
BREEZY SOUTHEAST WINDS WILL KEEP AN UPSLOPE FLOW OVER WESTERN
KANSAS TONIGHT. A STRONG COLD FRONT WILL BARREL DOWN FROM THE
NORTHWEST TUESDAY MORNING, SHIFTING WINDS TO STRONG NORTHWEST
WINDS. IFR CIGS AND MVFR VSBYS ARE EXPECTED TO DEVELOP AFTER 09Z
TONIGHT, BUT IMPROVE TO MVFR CIGS AND GOOD VSBYS BY 12Z OR SO WHEN
THE FRONT APPROACHES. CIGS AFTER 15Z SHOULD ALL BE IN THE
OVC12-015 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 57 19 36 23 / 30 30 10 0
GCK 43 17 34 23 / 30 30 0 0
EHA 38 17 37 24 / 20 20 0 0
LBL 46 18 36 24 / 20 20 0 0
HYS 49 19 36 24 / 40 50 10 0
P28 70 25 43 27 / 40 50 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY UNTIL 10 PM CDT /9 PM MDT/ THIS EVENING FOR KSZ030-
031-043>046-061>065-074>080-084>089.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...BURKE
LONG TERM...JJOHNSON
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
234 AM CDT TUE APR 9 2013
...UPDATED TO SHORT TERM, WITH WIND ADVISORY INFO BELOW...
.SYNOPSIS...
ISSUED AT 340 PM CDT MON APR 8 2013
THE 12Z UPPER AIR ANALYSIS SHOWED INCREASING SOUTHWESTERLY FLOW OVER
THE CENTRAL HIGH PLAINS. THIS WAS AHEAD OF AN UPPER TROUGH THAT WAS
DIGGING SOUTHWARD THROUGH THE WESTERN STATES WITH THE HELP OF A 130
KNOT JET AT 250 MB JUST OFF THE OR/WA COAST. AT THE SURFACE, LOW
PRESSURE WAS DEEPENING OVER EASTERN COLORADO. A WARM FRONT EXTENDED
FROM THE LOW ACROSS THE OKLAHOMA PANHANDLE INTO NORTHERN OKLAHOMA.
SURFACE DEWPOINTS HAVE BEEN INCREASING OVER THE CENTRAL AND SOUTHERN
PLAINS OVER THE WEEKEND WITH DEWPOINTS IN THE UPPER 50S/LOW 60S OVER
CENTRAL KANSAS WITH UPPER 40 TO MID 50 DEWPOINTS PUSHING BACK INTO
THE WESTERN HIGH PLAINS TO THE NORTH OF THE WARM FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 231 AM CDT TUE APR 9 2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 PM CDT MON APR 8 2013
A CHALLENGING FORECAST IS IN STORE FOR TUESDAY NIGHT WITH RESPECT TO
PRECIPITATION CHANCES AND PRECIPITATION TYPE. WINDY CONDITIONS
USHER IN MUCH COLDER AIR FOR WEDNESDAY MORNING, FOLLOWED BY A
GRADUAL WARMUP TOWARD THE WEEKEND WITH MINOR OPPORTUNITIES FOR LIGHT
PRECIPITATION.
THE INITIAL FORECAST CHALLENGE REVOLVES AROUND CHANCES FOR
PRECIPITATION TUESDAY EVENING. THE MODELS ARE IN GENERALLY GOOD
CONSENSUS IN EJECTING THE 700 MB LOW ACROSS SOUTHWEST NEBRASKA,
PLACING THE BEST SIGNAL FOR MOIST CONVEYOR BELT PRECIPITATION ACROSS
SOUTH CENTRAL AND CENTRAL KANSAS. POTENTIAL FOR A SIGNIFICANT
PORTION OF SOUTHWEST KANSAS TO BE IN THE DRY SLOT REGION EXISTS.
WITH THESE FACTORS IN MIND, THE LOWEST CHANCES FOR ACCUMULATING
PRECIPITATION ARE IN THE FAR WEST WITH BETTER CHANCES ACROSS THE
CENTRAL REGION. THE THERMODYNAMIC PROFILES FROM A TOP DOWN
PERSPECTIVE ALSO SUGGEST A CHANCE FOR FREEZING RAIN OR EVEN ICE
PELLETS (SLEET) IN A NARROW TIME WINDOW AFTER THE INTENSE LOW LEVEL
WARM ADVECTION OCCURS ACROSS THE AREA. GROUND TEMPERATURES ARE WARM
ENOUGH AT THIS TIME OF YEAR (MID 50`S IN THE MORNING) THAT FREEZING
RAIN ON THE GROUND WILL NOT BE AN ISSUE, BUT RATHER FREEZING OF
ELEVATED SURFACES. THE DEEPER COLD AIR MAY QUICKLY CAUSE POTENTIAL
FOR SNOW WITH LIGHT ACCUMULATIONS THROUGH THE OVERNIGHT IF DRY
SLOTTING DOES NOT OCCUR.
WEDNESDAY MORNING SHOULD BE COLD WITH TEMPERATURES AS LOW AS THE
TEENS AND 20`S. ALTHOUGH MUCH BELOW NORMAL, IT IS NOT COMPLETELY
UNCOMMON, AS THE CLIMATOLOGICAL LAST FREEZE FOR SOUTHWEST AND SOUTH
CENTRAL KANSAS IS GENERALLY CENTERED AROUND 10 DAYS FROM NOW.
THE REMAINDER OF THE WEEK WILL BRING A SLOW MODERATION OF
TEMPERATURES TOWARD NORMAL AS BROAD CYCLONIC UPPER FLOW DOMINATES
THE UPPER FLOW. MODELS INDICATE ADDITIONAL EMBEDDED WAVES INTO
THE ROCKIES REGION WHICH PRODUCE RAIN/SNOW EPISODES ACROSS THE FAR
CENTRAL HIGH PLAINS CENTERED AROUND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM CDT TUE APR 9 2013
BREEZY SOUTHEAST WINDS WILL KEEP AN UPSLOPE FLOW OVER WESTERN
KANSAS TONIGHT. A STRONG COLD FRONT WILL BARREL DOWN FROM THE
NORTHWEST TUESDAY MORNING, SHIFTING WINDS TO STRONG NORTHWEST
WINDS. IFR CIGS AND MVFR VSBYS ARE EXPECTED TO DEVELOP AFTER 09Z
TONIGHT, BUT IMPROVE TO MVFR CIGS AND GOOD VSBYS BY 12Z OR SO WHEN
THE FRONT APPROACHES. CIGS AFTER 15Z SHOULD ALL BE IN THE
OVC12-015 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 19 37 24 / 30 30 10 10
GCK 51 17 35 23 / 30 30 10 10
EHA 46 17 38 24 / 20 20 0 0
LBL 53 18 37 24 / 20 20 10 0
HYS 60 19 37 27 / 40 50 10 10
P28 74 25 44 29 / 40 50 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY FROM 7 AM CDT /6 AM MDT/ THIS MORNING TO 10 PM CDT
/9 PM MDT/ THIS EVENING FOR KSZ030-031-043>046-061>065-074>080-
084>089.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...BURKE
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS DODGE CITY KS
207 AM CDT TUE APR 9 2013
...UPDATE FOR THE SHORT TERM DISCUSSION...
.SYNOPSIS...
ISSUED AT 340 PM CDT MON APR 8 2013
THE 12Z UPPER AIR ANALYSIS SHOWED INCREASING SOUTHWESTERLY FLOW OVER
THE CENTRAL HIGH PLAINS. THIS WAS AHEAD OF AN UPPER TROUGH THAT WAS
DIGGING SOUTHWARD THROUGH THE WESTERN STATES WITH THE HELP OF A 130
KNOT JET AT 250 MB JUST OFF THE OR/WA COAST. AT THE SURFACE, LOW
PRESSURE WAS DEEPENING OVER EASTERN COLORADO. A WARM FRONT EXTENDED
FROM THE LOW ACROSS THE OKLAHOMA PANHANDLE INTO NORTHERN OKLAHOMA.
SURFACE DEWPOINTS HAVE BEEN INCREASING OVER THE CENTRAL AND SOUTHERN
PLAINS OVER THE WEEKEND WITH DEWPOINTS IN THE UPPER 50S/LOW 60S OVER
CENTRAL KANSAS WITH UPPER 40 TO MID 50 DEWPOINTS PUSHING BACK INTO
THE WESTERN HIGH PLAINS TO THE NORTH OF THE WARM FRONT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 203 AM CDT TUE APR 9 2013
THIS MORNING SHOULD START OUT WITH LOWER CLOUDS AND SOME LIGHT FOG
AROUND, MAINLY DUE TO THE GOOD SOUTHEASTERLY FLOW IN PLACE. THE
BIGGER CHALLENGE IS HOW FAST WILL THE STRONG COLD FRONT BLAST
THROUGH OUR FORECAST AREA. AFTER LOOKING AT SEVERAL MODELS, THE RUC
AND THE ECMWF MODELS ARE BOTH FASTER MOVING THE COLD FRONT THROUGH
THEN THE NAM AND WRF MODELS. SO FOR NOW, AM LEANING HEAVIER ON THE
FASTER SOLUTIONS, AS THIS IS DEEP, VERY COLD AIR. OF LATE, COLD AIR
MASSES HAVE BEEN MOVING FASTER THAN THE MODELS HAVE FORECAST.
BASED ON THE RUC AND EC TIMING, THE FRONT WILL BE THROUGH GARDEN
CITY AREA BY 12 TO 13Z, THE DODGE CITY AND HAYS AREAS BY 14 TO 16Z,
AND THROUGH THE PRATT AND MEDICINE LODGE AREAS BY AROUND 21Z. FOR
THIS REASON, I LOWERED TEMPS IN THE 21-00Z TIME FRAME IN THE MEDICINE
LODGE AREA, THINKING THE COLD AIR WILL HAVE NO PROBLEM BLASTING
THROUGH THERE PRIOR TO 00Z. WILL BE HOISTING A WIND ADVISORY FOR ALL
OF OUR FORECAST AREA, WITH STRONG NORTHWEST WINDS IN OUR WEST BY 15Z
AND SPREADING OUR SOUTHEAST ZONES BY 21Z. MOST AREAS WILL SEE A
NON-DIURNAL TEMPERATURE PATTERN TODAY, WITH HIGHS OCCURRING IN THE
MORNING OR EARLY AFTERNOON, BEFORE FALLING SIGNIFICANTLY BEHIND THE
FRONT. WINDS WILL SHIFT ABRUPTLY TO THE NORTHWEST BEHIND THE FRONT,
AND THIS CHANCE OF BOTH TEMPS AND WINDS WILL COME SUDDENLY FOR MOST
SOUTHWESTERN KANSANS. SINCE THERE IS WILL SUCH A FAST CHANGE OVER
TO COLD TEMPERATURES, SOME LIGHT RAIN MAY DEVELOP INITIALLY JUST
BEHIND THE FRONT, THEN AS THE COLUMN COOLS DOWN, SOME LIGHT SNOW IS
PROBABLE IN THE OUR EXTREME WESTERN COUNTIES THIS MORNING, SPREADING
LIGHT SNOW CHANCES TO THE EAST DURING THE DAY, AND TO OUR FAR
SOUTHEAST ZONES BY LATE AFTERNOON. THERE COULD BE A FEW
THUNDERSTORMS IN THE SAINT JOHN TO ASHLAND AREA AND SOUTHEASTWARD
DURING THE MID AFTERNOON. THE FRONT IS QUITE STRONG AND WILL RUN
INTO SOME UNSTABLE AIR AS IT REACHES EAST OF HIGHWAY 183 THIS
AFTERNOON. SPC HAS THE SLIGHT RISK AREA JUST TOUCHING OUR FAR
SOUTHEASTERN CWA, AND WILL MENTION THUNDERSTORM CHANCES IN THE HWO.
TONIGHT LOOKS COLD. COLD AIR ADVECTION WILL BE IN FULL FORCE, WITH
COMPRESSION TAKING PLACE AT THE LOWER LAYERS. NORTHWEST WINDS WILL
MAINTAIN IN THE 20 TO 25 MPH RANGE. OUR EASTERN HALF OF THE FORECAST
AREA, EAST OF A LINE FROM WAKEENEY TO KINSLEY TO COLDWATER MAY SEE
SOME LIGHT FREEZING RAIN OR SLEET FOR A SHORT PERIOD TONIGHT,
MAINLY AFTER MIDNIGHT. DO NOT EXPECT THIS FREEZING PRECIP TO
AMOUNT TO TOO MUCH, AND THINK ANY ICE ACCUMULATION WILL BE SPOTTY.
ANY SLEET OR FREEZING RAIN WILL CHANGE OVER TO SNOW BY MORNING,
BUT MOST OF THAT WILL ALSO HAVE MOVED EAST OF OUR FORECAST AREA BY
MORNING. HIGHEST PRECIPITATION CHANCES WILL BE IN THE 40 TO 44
PERCENT RANGE AND IN OUR EASTERN CWA. LOWER POPS IN THE 20
PERCENT RANGE WILL BE FROM DIGHTON TO DODGE CITY TO MEADE COUNTY.
MIN TEMPS WILL BE TRICKY, SO I STAYED WITH THE PREVIOUS FORECAST
OF LOWS DOWN TO 15 TO 16F FROM SYRACUSE TO WAKEENEY, AND AS HIGH
AS 25F DEGREES NEAR KIOWA.
.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 340 PM CDT MON APR 8 2013
A CHALLENGING FORECAST IS IN STORE FOR TUESDAY NIGHT WITH RESPECT TO
PRECIPITATION CHANCES AND PRECIPITATION TYPE. WINDY CONDITIONS
USHER IN MUCH COLDER AIR FOR WEDNESDAY MORNING, FOLLOWED BY A
GRADUAL WARMUP TOWARD THE WEEKEND WITH MINOR OPPORTUNITIES FOR LIGHT
PRECIPITATION.
THE INITIAL FORECAST CHALLENGE REVOLVES AROUND CHANCES FOR
PRECIPITATION TUESDAY EVENING. THE MODELS ARE IN GENERALLY GOOD
CONSENSUS IN EJECTING THE 700 MB LOW ACROSS SOUTHWEST NEBRASKA,
PLACING THE BEST SIGNAL FOR MOIST CONVEYOR BELT PRECIPITATION ACROSS
SOUTH CENTRAL AND CENTRAL KANSAS. POTENTIAL FOR A SIGNIFICANT
PORTION OF SOUTHWEST KANSAS TO BE IN THE DRY SLOT REGION EXISTS.
WITH THESE FACTORS IN MIND, THE LOWEST CHANCES FOR ACCUMULATING
PRECIPITATION ARE IN THE FAR WEST WITH BETTER CHANCES ACROSS THE
CENTRAL REGION. THE THERMODYNAMIC PROFILES FROM A TOP DOWN
PERSPECTIVE ALSO SUGGEST A CHANCE FOR FREEZING RAIN OR EVEN ICE
PELLETS (SLEET) IN A NARROW TIME WINDOW AFTER THE INTENSE LOW LEVEL
WARM ADVECTION OCCURS ACROSS THE AREA. GROUND TEMPERATURES ARE WARM
ENOUGH AT THIS TIME OF YEAR (MID 50`S IN THE MORNING) THAT FREEZING
RAIN ON THE GROUND WILL NOT BE AN ISSUE, BUT RATHER FREEZING OF
ELEVATED SURFACES. THE DEEPER COLD AIR MAY QUICKLY CAUSE POTENTIAL
FOR SNOW WITH LIGHT ACCUMULATIONS THROUGH THE OVERNIGHT IF DRY
SLOTTING DOES NOT OCCUR.
WEDNESDAY MORNING SHOULD BE COLD WITH TEMPERATURES AS LOW AS THE
TEENS AND 20`S. ALTHOUGH MUCH BELOW NORMAL, IT IS NOT COMPLETELY
UNCOMMON, AS THE CLIMATOLOGICAL LAST FREEZE FOR SOUTHWEST AND SOUTH
CENTRAL KANSAS IS GENERALLY CENTERED AROUND 10 DAYS FROM NOW.
THE REMAINDER OF THE WEEK WILL BRING A SLOW MODERATION OF
TEMPERATURES TOWARD NORMAL AS BROAD CYCLONIC UPPER FLOW DOMINATES
THE UPPER FLOW. MODELS INDICATE ADDITIONAL EMBEDDED WAVES INTO
THE ROCKIES REGION WHICH PRODUCE RAIN/SNOW EPISODES ACROSS THE FAR
CENTRAL HIGH PLAINS CENTERED AROUND FRIDAY.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1226 AM CDT TUE APR 9 2013
BREEZY SOUTHEAST WINDS WILL KEEP AN UPSLOPE FLOW OVER WESTERN
KANSAS TONIGHT. A STRONG COLD FRONT WILL BARREL DOWN FROM THE
NORTHWEST TUESDAY MORNING, SHIFTING WINDS TO STRONG NORTHWEST
WINDS. IFR CIGS AND MVFR VSBYS ARE EXPECTED TO DEVELOP AFTER 09Z
TONIGHT, BUT IMPROVE TO MVFR CIGS AND GOOD VSBYS BY 12Z OR SO WHEN
THE FRONT APPROACHES. CIGS AFTER 15Z SHOULD ALL BE IN THE
OVC12-015 RANGE.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 19 37 24 / 20 30 10 10
GCK 51 17 35 23 / 30 30 10 10
EHA 46 17 38 24 / 20 20 0 0
LBL 53 18 37 24 / 20 20 10 0
HYS 60 19 37 27 / 40 50 10 10
P28 74 25 44 29 / 40 50 20 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...GERARD
SHORT TERM...BURKE
LONG TERM...RUSSELL
AVIATION...BURKE
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1212 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1008 PM CDT MON APR 8 2013
MOST OF THE PRECIPITATION THIS EVENING HAS BEEN FOCUSED ACROSS FAR
NORTHWEST KANSAS AND SOUTHWEST AND CENTRAL NEBRASKA WHERE A FRONT
STRETCHES OVER THE AREA. LATEST TOP SOUNDING CONTINUED TO SHOW A
DECENT CAPPING INVERSION IN PLACE NEAR 700 MB...WITH MODEL SOUNDINGS
SHOWING LITTLE CHANGE THROUGH THE OVERNIGHT PERIOD. AS A
RESULT...HAVE CONTINUED TO TREND DOWN POPS ACROSS MUCH OF THE
CWA...ESPECIALLY OVER EAST CENTRAL KANSAS. WITH THE LLJ INCREASING
OVER NORTH CENTRAL AND NORTHEAST KANSAS TONIGHT...STILL CANNOT RULE
OUT SOME SCATTERED SHOWER AND THUNDERSTORM ACTIVITY DEVELOPING THIS
EVENING NEAR THE NEBRASKA/KANSAS BORDER...SO HAVE KEPT CHANCE POPS
IN FOR THAT AREA THROUGH THE OVERNIGHT HOURS.
&&
.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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1211 AM CDT TUE APR 9 2013
FOR 06Z TAFS...AN AREA OF MVFR CIGS OVER CENTRAL AND SOUTHERN KANSAS
IS EXPECTED TO SPREAD EASTWARD OVER THE TAF SITES THROUGH THE
OVERNIGHT HOURS. MODEL SOUNDINGS CONTINUE TO HINT AT THE POTENTIAL
FOR A BRIEF PERIOD OF BORDERLINE IFR/MVFR CIGS AROUND SUNRISE.
OTHERWISE...MVFR CIGS SHOULD PERSIST THROUGH THE DAY WITH THE
POTENTIAL FOR SHOWERS AND THUNDERSTORMS INCREASING BY LATE AFTERNOON
AND PERSISTING THROUGH THE EVENING HOURS AS A STRONG COLD FRONT
PASSES WEST TO EAST ACROSS THE TAF SITES. MUCH OF THE PRECIPITATION
IS EXPECTED TO DEVELOP ALONG AND BEHIND THIS FRONT. HAVE ADDED IN
VCTS FOR THE END OF THE PERIOD AND WILL NARROW DOWN THE TIMING IN
FUTURE UPDATES AS CONFIDENCE INCREASES.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HENNECKE
SHORT TERM...WOLTERS
LONG TERM...CRAVEN
AVIATION...HENNECKE
AREA FORECAST DISCUSSION
NWS PADUCAH KY
1143 PM CDT MON APR 8 2013
.UPDATE...
ISSUED AT 1143 PM CDT MON APR 8 2013
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.
UPDATE ISSUED AT 907 PM CDT MON APR 8 2013
HAVE UPDATED TWICE THIS EVENING TO CATCH UP TO TRENDS IN MOST
ELEMENTS. THE RUC SEEMS TO BE HANDLING THE SITUATION QUITE
WELL...SO FOLLOWED IT CLOSELY.
THE FIRST 2 ISSUES ARE THE RAPID SOUTH TO NORTH CLEARING...AND
THE WINDS ARE MUCH LIGHTER THAN MOST GUIDANCE WOULD INDICATE FOR
THE THIRD STRAIGHT NIGHT. OF COURSE THIS BRINGS GREATER
RADIATIONAL COOLING INTO PLAY. THE FINAL TREND OF LOWER 50
DEWPOINTS ADVECTING NORTHWARD OUT OF WEST TENNESSEE LEADS TO MORE
COOLING THAN PREVIOUSLY EXPECTED. KNOCKED LOWS DOWN A
CATEGORY...GENERALLY INTO THE UPPER 50S...BUT WOULD NOT BE SHOCKED
TO SEE A FEW SITES IN WEST KENTUCKY DROP INTO THE MIDDLE 50S.
&&
.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 329 PM CDT MON APR 8 2013
SREF AND NAM ARE TRENDING DRIER TONIGHT INTO TUESDAY...WHILE GFS
AND ECMWF SHOW WIDESPREAD LIGHT PRECIP LATE TONIGHT AND EARLY
TUESDAY. ECHOES THAT MOVED ACROSS OUR REGION TODAY PRODUCED MAINLY
SPRINKLES AT BEST. SREF AND NAM DID BETTER TODAY...AND IT SEEMS
LEANING TOWARD THE DRIER SOLUTIONS IN THE NEAR TERM IS A BETTER
BET...SO REMOVED POPS FOR TONIGHT AND TUESDAY. A STRAY SHOWER
ACROSS MAINLY OUR NORTHERN COUNTIES IS NOT OUT OF THE
QUESTION...BUT CHANCES JUST ARE NOT GOOD ENOUGH TO WARRANT A POP
AT THIS POINT.
THE LOW PRESSURE SYSTEM WILL BE MOVING CLOSER BY TUESDAY
NIGHT...AND MODELS ARE IN PRETTY GOOD AGREEMENT KEEPING OUR REGION
DRY THROUGH MIDNIGHT. DID INCLUDE SLIGHT CHANCE POPS FOR OUR
EXTREME WESTERN COUNTIES TUESDAY EVENING TO BETTER BLEND WITH OUR
NEIGHBORS. AFTER 06Z...MODELS SPREAD SOME LIGHT QPF INTO MUCH OF
SOUTHERN ILLINOIS AND SOUTHEAST MISSOURI. WENT WITH LIKELY POPS
FAR WEST TO CHANCE AND SLIGHT CHANCE ACROSS MUCH OF SOUTHERN
ILLINOIS AND A GOOD PORTION OF SOUTHEAST MISSOURI...THOUGH QPF
AMOUNTS DO NOT LOOK TOO SIGNIFICANT AT THIS POINT.
TEMPERATURES WILL REMAIN UNSEASONABLY WARM THROUGH THE PERIOD.
LEANED ON THE WARM SIDE OF GUIDANCE FOR LOWS AND THE COOLER SIDE OF
GUIDANCE FOR HIGHS BASED ON WINDS STAYING UP AND EXPECTED CLOUD
COVER.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 329 PM CDT MON APR 8 2013
THE MAIN FOCUS IN THIS TIME FRAME WILL COME WITH THE MID WEEK COLD
FRONT AND MID LEVEL SHORT WAVE THAT WILL BE APPROACHING THE MS RIVER
VALLEY LATE WED AND WED NIGHT. DETERMINISTIC MODEL RUNS OF THE
GFS/ECMWF ARE STILL NOT IN GOOD ENOUGH AGREEMENT REGARDING THE
TIMING OF THESE FEATURES TO HAVE A HIGH DEGREE OF CONFIDENCE AS TO
THE DEGREE OVER LOW LEVEL INSTABILITY THAT WILL BE AVAILABLE ONCE
THE FRONT ENTERS THE FORECAST AREA. THE OPERATIONAL GFS CONTINUES
TO BE THE QUICKEST/MOST PROGRESSIVE MODEL...THO IT HAS TRENDED
SLOWER FROM THE OVERNIGHT RUN. THUS...HAVE OPTED TO FOLLOW HPC/WPC
THOUGHTS AND SIDE A BIT MORE TOWARD THE SLOWER/MORE CONSISTENT 12Z
EURO RUN WITH THIS PACKAGE.
WITH THAT SAID...IT LOOKS AS THOUGH THE MAIN PUSH OF POTENTIAL
SEVERE STORMS AND/OR HEAVY RAINFALL WILL COME ALONG AND JUST BEHIND
THE COLD FRONT WED EVENING OVER SE MO...THEN LATER WED EVE INTO THE
OVERNIGHT AND EARLY AM HOURS THU EAST OF THE MS RIVER. EVEN THO LOW
LEVEL INSTABILITY WILL WANE DURING THE NIGHT TIME HOURS...IT STILL
APPEARS THAT AT LEAST MODEST INSTABILITY WILL PERSIST AHEAD OF THE
FRONT...ALONG WITH QUITE IMPRESSIVE 0-1 KM SHEAR/HELICITY VALUES.
WITH SFC DEW POINTS EXPECTED TO RISE/POOL INTO THE MID 60S JUST
AHEAD OF THE SFC FRONT....WILL NOT TAKE MUCH INSTABILITY TO SUPPORT
AT LEAST ISOLATED SEVERE WINDS AND POSSIBLY A COUPLE OF TORNADOES
WED NIGHT JUST AHEAD OF THE SFC FRONT AS IT APPROACHES. AT THIS
TIME...WOULD NOT BE AT ALL SURPRISED IF WE END UP WITH TOR WATCH
BOXES STACKED FROM WEST TO EAST ACROSS THE FORECAST AREA WED EVENING
INTO EARLY THU.
THEREAFTER...RAIN FREE CONDITIONS ARE EXPECTED FOR THE LATE
WEEK/WEEKEND TIME FRAME AS HIGH PRESSURE TAKES OVER. AFTER A BRIEF
CHILL BEHIND THE FRONT THU/THU NIGHT...SOUTHERLY WINDS SHOULD RETURN
IN THE FRI THRU SUN TIME FRAME...AND BRING US BACK INTO THE 60S AND
70S IN TIME FOR THE WEEKEND.
&&
.AVIATION...
ISSUED AT 1143 PM CDT MON APR 8 2013
TRIED TO MODEL THE 06Z TAFS AFTER THE TRENDS FROM TODAY. GUIDANCE
CANNOT HANDLE THE LOW-LEVEL MOISTURE...AND IT HAS BEEN CHRONICALLY
TOO WINDY AT NIGHT. THE 5-6KFT CLOUDS HAVE LIFTED NORTHWARD AND
ARE NOT CURRENTLY IMPACTING ANY TERMINALS. THERE IS AN AREA OF
MVFR CEILINGS IN EAST TEXAS THAT IS SURE TO MOVE NORTHWARD TOWARD
OUR REGION OVERNIGHT...BUT FEEL THAT THEY...AS HAS BEEN THE CASE
LATELY...WILL BE AT VFR LEVELS WHEN THEY ARRIVE HERE. THE OTHER
CONCERN OVERNIGHT IS LLWS. KLZK VAD WIND PROFILE HAS 50KTS AT
2KFT...BUT KPAH IS HOLDING AT 35KTS. DID NOT MENTION IT WITH THIS
ISSUANCE...BUT IT WILL NEED TO BE MONITORED CLOSELY...ESPECIALLY
GIVEN THE LIGHT SURFACE WINDS.
FOR TUESDAY WILL EXPECT TO SEE CEILINGS AT LEAST THROUGH THE
MORNING IN THE 4-6KFT LAYER...AND A REPEAT OF THE GUSTY SOUTH
SOUTHWEST WINDS WE HAVE HAD FOR THE PAST FEW DAYS. SOME GUSTS
20-25KTS WILL BE POSSIBLE AT ALL SITES THROUGH THE DAY...WITH THE
HIGHEST GUSTS OCCURRING WHEN AND WHERE BETTER MIXING/MORE SUNSHINE
OCCURS. FOLLOWING THE OBSERVATIONS FROM THE LAST 2 NIGHTS...WILL
LIKELY SEE WINDS DROP OFF TO AROUND 5KTS ALL SITES WITH
SUNSET...AND SOME GUIDANCE ACTUALLY SHOWS SCATTERING OF THE LOWER
CLOUDS...SO WILL NOT CARRY ANY CEILINGS FOR TUESDAY EVENING.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
&&
$$
UPDATE...DRS
SHORT TERM...RST
LONG TERM...GM
AVIATION...DRS
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
1154 PM EDT WED APR 10 2013
.AVIATION...
//DISCUSSION...
THE NEXT BATCH OF RAIN NOW MOVING INTO SRN LAKE MI WILL ADVANCE
ACROSS SE MI JUST PRIOR TO DAYBREAK. THERE REMAINS THE POTENTIAL FOR
SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS THROUGH THE DAY ON
THURSDAY. TEMPS AT MBS SHOULD REMAIN JUST ABOVE FREEZING THROUGH THE
MORNING...SO THE RISK OF ICING ON THE RUNWAY SURFACE NOW APPEARS
QUITE LOW AND WILL BE REMOVED FROM THE MBS TAF. LOW LEVEL DRY AIR
ADVECTING IN FROM THE NORTHEAST HAS ACTUALLY SCOURED THE IFR STRATUS
DECK OUT ALL THE WAY SOUTH TO FNT. AS THE RAIN MOVES BACK IN THIS
MORNING...EXPECT THE ADDED LOW LEVEL MOISTURE WILL RESULT IN A DROP
IN THE CLOUDS AT FNT AND MBS. PTK INTO METRO DETROIT SHOULD REMAIN
WITHIN THE IFR DECK INTO TONIGHT.
FOR DTW...THERE WILL AGAIN BE THE POSSIBILITY OF PERIODIC
THUNDERSTORMS ON THURSDAY. STRONG LOW LEVEL MOISTURE TRANSPORT WILL
BE ENHANCED VIA LOW LEVEL CONVERGENCE THURS MORNING. THIS ADDED
MOISTURE AND INSTABILITY FLUX WILL SUPPORT A CHANCE OF THUNDERSTORMS
MON MORNING...CONFIDENCE ON TIMING AND POTENTIAL OF THUNDER THURS
AFTERNOON IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE CEILINGS WILL REMAIN BELOW 5000 FT THROUGH THE TAF
PERIOD.
* LOW CONFIDENCE ON TIMING AND POTENTIAL FOR THUNDERSTORMS LATE
TONIGHT THROUGH THURSDAY EVENING.
&&
.PREV DISCUSSION...ISSUED 925 PM EDT WED APR 10 2013
UPDATE...
IN SHORT...THE FLOOD WATCH WILL REMAIN IN EFFECT FOR THE ENTIRE
FORECAST AREA AND THE FREEZING RAIN ADVISORY WILL REMAIN IN EFFECT
FOR THE SAGINAW VALLEY AND THUMB.
THE EXTENT OF CONVECTION ACROSS THE OHIO VALLEY /WHICH HAS BEEN
UNDERESTIMATED BY THE 18Z MODEL SUITE/ RAISES SOME CONCERNS AS TO
HOW FAR NORTH THE REGION OF CONVECTION NOW EXPANDING ACROSS NRN
ILLINOIS WILL LIFT. THE 00Z KAPX SOUNDING ALSO SHOWED A FORMIDABLE
DRY LAYER BELOW 800MB. NONETHELESS...THE FORECAST STRENGTHENING OF
THE LOW LEVEL JET TO 50 TO 60 KNOTS OVERNIGHT WILL FOCUS GOOD
MOISTURE CONVERGENCE INTO THE TIGHT LOWER TROPOSPHERIC BAROCLINIC
ZONE ACROSS SRN LOWER MI. THESE FACTORS SUPPORT THE ONGOING
FORECAST OF CATEGORICAL POPS REDEVELOPING LATE TONIGHT INTO THURS
MORNING. THE ELEVATED CONVECTIVE POTENTIAL AND MOISTURE TRANSPORT
WILL CONTINUE TO POSE SOME FLOODING CONCERNS. THERE HAVE BEEN
SOME REPORTS OF HIGH WATER IN STREAMS AND RIVERS AND SOME WATER
COVERED ROADS ACROSS THE NORTHERN HALF OF THE FORECAST AREA.
SURFACE DEWPOINTS ACROSS THE FREEZING RAIN ADVISORY AREA HAVE NOW
DROPPED TO 32 TO 33 DEG UNDER THE DRY NORTHEAST FLOW. THERE IS
GROWING CONFIDENCE THAT DEWPOINTS WILL FALL BELOW FREEZING
OVERNIGHT. THE WIND MAY HOWEVER KEEP THE BOUNDARY LAYER MIXED
ENOUGH TO HOLD SFC TEMPS AT OR JUST SLIGHTLY ABOVE FREEZING. AS
MENTIONED IN THE PREVIOUS DISCUSSION...THE SUB FREEZING LAYER WILL
BE RELATIVELY DEEP /3K FT/. SO EVEN IF SURFACE TEMPS HOLD ABOVE
FREEZING...ELEVATED SURFACES /TREES AND POWER LINES/ MAY STILL
BECOME COATED WITH ICE. THE BIGGEST CONCERN AT THIS POINT IS THE
POTENTIAL FOR THE HEAVIER PRECIP TO REMAIN SOUTH OF THE ADVISORY
AREA.
SO ONLY A FEW MINOR ADJUSTMENTS ARE PLANNED FOR THE EVENING
UPDATES...WHICH WILL BE ISSUED WITHIN THE NEXT HOUR.
PREV DISCUSSION...ISSUED 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.
&&
.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...
SMALL CRAFT ADVISORY...FROM 8 AM THURSDAY TO 5 PM THURSDAY.
&&
$$
AVIATION.....SC
UPDATE.......SC
SHORT TERM...CB
LONG TERM....DG
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
925 PM EDT WED APR 10 2013
.UPDATE...
IN SHORT...THE FLOOD WATCH WILL REMAIN IN EFFECT FOR THE ENTIRE
FORECAST AREA AND THE FREEZING RAIN ADVISORY WILL REMAIN IN EFFECT
FOR THE SAGINAW VALLEY AND THUMB.
THE EXTENT OF CONVECTION ACROSS THE OHIO VALLEY /WHICH HAS BEEN
UNDERESTIMATED BY THE 18Z MODEL SUITE/ RAISES SOME CONCERNS AS TO
HOW FAR NORTH THE REGION OF CONVECTION NOW EXPANDING ACROSS NRN
ILLINOIS WILL LIFT. THE 00Z KAPX SOUNDING ALSO SHOWED A FORMIDABLE
DRY LAYER BELOW 800MB. NONETHELESS...THE FORECAST STRENGTHENING OF
THE LOW LEVEL JET TO 50 TO 60 KNOTS OVERNIGHT WILL FOCUS GOOD
MOISTURE CONVERGENCE INTO THE TIGHT LOWER TROPOSPHERIC BAROCLINIC
ZONE ACROSS SRN LOWER MI. THESE FACTORS SUPPORT THE ONGOING
FORECAST OF CATEGORICAL POPS REDEVELOPING LATE TONIGHT INTO THURS
MORNING. THE ELEVATED CONVECTIVE POTENTIAL AND MOISTURE TRANSPORT
WILL CONTINUE TO POSE SOME FLOODING CONCERNS. THERE HAVE BEEN
SOME REPORTS OF HIGH WATER IN STREAMS AND RIVERS AND SOME WATER
COVERED ROADS ACROSS THE NORTHERN HALF OF THE FORECAST AREA.
SURFACE DEWPOINTS ACROSS THE FREEZING RAIN ADVISORY AREA HAVE NOW
DROPPED TO 32 TO 33 DEG UNDER THE DRY NORTHEAST FLOW. THERE IS
GROWING CONFIDENCE THAT DEWPOINTS WILL FALL BELOW FREEZING
OVERNIGHT. THE WIND MAY HOWEVER KEEP THE BOUNDARY LAYER MIXED
ENOUGH TO HOLD SFC TEMPS AT OR JUST SLIGHTLY ABOVE FREEZING. AS
MENTIONED IN THE PREVIOUS DISCUSSION...THE SUB FREEZING LAYER WILL
BE RELATIVELY DEEP /3K FT/. SO EVEN IF SURFACE TEMPS HOLD ABOVE
FREEZING...ELEVATED SURFACES /TREES AND POWER LINES/ MAY STILL
BECOME COATED WITH ICE. THE BIGGEST CONCERN AT THIS POINT IS THE
POTENTIAL FOR THE HEAVIER PRECIP TO REMAIN SOUTH OF THE ADVISORY
AREA.
SO ONLY A FEW MINOR ADJUSTMENTS ARE PLANNED FOR THE EVENING
UPDATES...WHICH WILL BE ISSUED WITHIN THE NEXT HOUR.
&&
.AVIATION...ISSUED 706 PM EDT WED APR 10 2013
//DISCUSSION...
THERE WILL BE A LULL IN THE RAINFALL OVER MUCH OF SE MI THIS EVENING
INTO THE OVERNIGHT IN THE WAKE OF THIS AFTERNOON THUNDERSTORM
COMPLEX. ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP TO THE WEST OVERNIGHT AND ADVANCE ACROSS SE MI THURSDAY
MORNING AS LOW PRESSURE LIFTS INTO NRN INDIANA. THERE IS THE
POTENTIAL FOR SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS ON
THURSDAY. TEMPERATURES WILL DROP NEAR FREEZING AT MBS BY EARLY THURS
MORNING...WHICH WILL CONTINUE TO SUPPORT A CHANCE OF FZRA IN THE MBS
TAF. WHILE CEILINGS SHOULD REMAIN SOLIDLY IFR SOUTH OF FNT THROUGH
THE TAF PERIOD...WEAK DRY AIR ADVECTION NEAR THE SURFACE HAS BEEN
LIFTING CEILING BASES TO THE NORTH. THE OBSERVATIONAL TRENDS SUGGEST
SOME IMPROVEMENT IN CEILINGS WILL BE POSSIBLE AT MBS AND FNT THIS
EVENING PRIOR TO MORE WIDESPREAD RAIN MOVING IN TOWARD DAYBREAK.
FOR DTW...THERE WILL AGAIN BE THE POSSIBILITY OF PERIODIC
THUNDERSTORMS ON THURSDAY. STRONG LOW LEVEL MOISTURE TRANSPORT WILL
BE ENHANCED VIA LOW LEVEL CONVERGENCE LATE THURS MORNING. THIS ADDED
MOISTURE AND INSTABILITY FLUX WILL SUPPORT A CHANCE OF THUNDERSTORMS
12-15Z MON. CONFIDENCE ON TIMING AND POTENTIAL OF THUNDER THURS
AFTERNOON IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE CEILINGS WILL REMAIN BELOW 5000 FT THROUGH THE TAF
PERIOD.
* LOW CONFIDENCE ON TIMING AND POTENTIAL FOR THUNDERSTORMS LATE
TONIGHT THROUGH THURSDAY EVENING.
&&
.PREV DISCUSSION...ISSUED 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.
&&
.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.
&&
$$
UPDATE.......SC
AVIATION.....SC
SHORT TERM...CB
LONG TERM....DG
MARINE.......CB
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
706 PM EDT WED APR 10 2013
.AVIATION...
//DISCUSSION...
THERE WILL BE A LULL IN THE RAINFALL OVER MUCH OF SE MI THIS EVENING
INTO THE OVERNIGHT IN THE WAKE OF THIS AFTERNOON THUNDERSTORM
COMPLEX. ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
DEVELOP TO THE WEST OVERNIGHT AND ADVANCE ACROSS SE MI THURSDAY
MORNING AS LOW PRESSURE LIFTS INTO NRN INDIANA. THERE IS THE
POTENTIAL FOR SEVERAL ROUNDS OF SHOWERS AND THUNDERSTORMS ON
THURSDAY. TEMPERATURES WILL DROP NEAR FREEZING AT MBS BY EARLY THURS
MORNING...WHICH WILL CONTINUE TO SUPPORT A CHANCE OF FZRA IN THE MBS
TAF. WHILE CEILINGS SHOULD REMAIN SOLIDLY IFR SOUTH OF FNT THROUGH
THE TAF PERIOD...WEAK DRY AIR ADVECTION NEAR THE SURFACE HAS BEEN
LIFTING CEILING BASES TO THE NORTH. THE OBSERVATIONAL TRENDS SUGGEST
SOME IMPROVEMENT IN CEILINGS WILL BE POSSIBLE AT MBS AND FNT THIS
EVENING PRIOR TO MORE WIDESPREAD RAIN MOVING IN TOWARD DAYBREAK.
FOR DTW...THERE WILL AGAIN BE THE POSSIBILITY OF PERIODIC
THUNDERSTORMS ON THURSDAY. STRONG LOW LEVEL MOISTURE TRANSPORT WILL
BE ENHANCED VIA LOW LEVEL CONVERGENCE LATE THURS MORNING. THIS ADDED
MOISTURE AND INSTABILITY FLUX WILL SUPPORT A CHANCE OF THUNDERSTORMS
12-15Z MON. CONFIDENCE ON TIMING AND POTENTIAL OF THUNDER THURS
AFTERNOON IS TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME.
//DTW THRESHOLD THREATS...
* HIGH CONFIDENCE CEILINGS WILL REMAIN BELOW 5000 FT THROUGH THE TAF
PERIOD.
* LOW CONFIDENCE ON TIMING AND POTENTIAL FOR THUNDERSTORMS LATE
TONIGHT THROUGH THURSDAY EVENING.
&&
.PREV DISCUSSION...ISSUED 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.
&&
.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.
&&
$$
AVIATION.....SC
SHORT TERM...CB
LONG TERM....DG
MARINE.......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
646 PM EDT TUE APR 9 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 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 646 PM EDT TUE APR 9 2013
DRIER AIR WILL CONTINUE TO AFFECT IWD AND CMX AND CONTINUE THE VFR
CONDITIONS THERE AS HIGH CLOUDS FROM STORM SYSTEMS PASSING BY TO THE
SOUTH MOVE THROUGH. AT SAW...DRIER AIR IS SLOWER TO COME IN AND THE
MVFR CIG THAT IS THERE EARLY THIS EVENING WILL DISSIPATE AND VFR
CONDITIONS ARE THEN EXPECTED FOR THE REST OF THE PERIOD.
&&
.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 WEDNESDAY NIGHT THROUGH THURSDAY EVENING
FOR LSZ162-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
445 PM EDT TUE APR 9 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 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 140 PM EDT TUE APR 9 2013
NRLY UPSLOPE FLOW INTO SAW WILL CONTINUE TO SUSTAIN IFR CIGS THROUGH
MID AFTERNOON. HOWEVER...IMPROVENT TO MVFR IS EXPECTED BY LATE
AFTERNOON AND VFR THIS EVENING AS DRIER FROM NRN ONTARIO BUILDS INTO
THE REGION. SIMILARLY...AT IWD THE DRY AIR WILL ALSO HELP BOOST CIGS
FROM LOWER END MVFR TO VFR BY LATE AFTERNOON WHILE VFR CONDITIONS
WILL PERSIST AT CMX. WITH DRY NORTH WINDS CONTINUING OVERNIGHT INTO
WED...VFR CONDITIONS ARE EXPECTED TO PREVAIL.
&&
.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 WEDNESDAY NIGHT THROUGH THURSDAY EVENING
FOR LSZ162-263.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...JLB
LONG TERM...KF
AVIATION...JLB
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
142 PM EDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A COUPLE OF WELL-DEFINED
SHORTWAVES LIFTING NORTH AND EAST...ONE THROUGH KS/NE AND ANOTHER
THROUGH CENTRAL IA. THESE SHORTWAVES ALONG WITH GOOD UPR DIV AND
800-700 MB FGEN AND 295K ISENTROPIC ASCENT IN RIGHT ENTRANCE REGION
OF 110+ KT 250 MB JET MAX OVER NORTHERN ONTARIO SUPPORTING BAND OF
RAIN NOW LIFTING NORTH INTO NE IA AND SRN WI PER LATEST REGIONAL
RADAR LOOP. QUIET OVER UPR MI EARLY THIS MORNING OTHER THAN SOME
PATCHY DENSE FOG DUE TO PERSISTENT LOW-LVL MOISTURE OVER THE AREA.
BAND OF RAIN OVER NE IA AND SRN WI IS EXPECTED TO LIFT GRADUALLY
NORTH AND EAST TODAY AS STRENGTHENING UPR JET NEAR ONTARIO/MN MOVES
EAST THROUGH ONTARIO TODAY AND INTO WRN QUEBEC THIS EVENING. MODELS
SHOW TRANSLATING UPR JET SUPPORT AND ASSOC 800-700 MB FGEN FORCING
AND 295K ISENTROPIC ASCENT ALLOWING PCPN BAND TO SHIFT NORTH AND
EAST TOWARD SCNTRL UPR MI LATER THIS AFTERNOON AND EVENING.
DEVELOPING DRY ANTICYCLONIC NE FLOW AHEAD OF HIGH PRES BUILDING IN
FM THE NRN PLAINS AND SCNTRL CANADA WILL IN TURN WORK TO PROVIDE A
SHARP CUTOFF TO NRN EXTENT OF PCPN. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET AND RAIN IS POSSIBLE LATER THIS AFTERNOON OVER THE
SOUTHERN TIER OF UPR MI. PTYPE WILL BE LIKELY ALL RAIN OVER THE SRN
HALF OF MNM COUNTY WHERE SFC TEMPS CLIMB INTO THE UPPER 30S AND
LOWER 40S.
TONIGHT...FCST SNDGS SUGGEST PTYPES WILL LIKELY BE A MIX
OF SNOW AND SLEET FOR AREAS MAINLY SOUTH OF A LINE FROM IRON
MOUNTAIN TO MANISTIQUE. BEST CHC OF PCPN WILL BE NEAR MNM WHERE
LIKELY POPS WILL BE UTILIZED FOR A MIX OF SNOW/SLEET MIXTURE AND
POSSIBLE ACCUMULATION OF AROUND AN INCH. AGAIN EXPECT A SHARP CUTOFF
OF PCPN TO THE NORTH AS DRY NE FLOW PERSISTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 140 PM EDT TUE APR 9 2013
NRLY UPSLOPE FLOW INTO SAW WILL CONTINUE TO SUSTAIN IFR CIGS THROUGH
MID AFTERNOON. HOWEVER...IMPROVENT TO MVFR IS EXPECTED BY LATE
AFTERNOON AND VFR THIS EVENING AS DRIER FROM NRN ONTARIO BUILDS INTO
THE REGION. SIMILARLY...AT IWD THE DRY AIR WILL ALSO HELP BOOST CIGS
FROM LOWER END MVFR TO VFR BY LATE AFTERNOON WHILE VFR CONDITIONS
WILL PERSIST AT CMX. WITH DRY NORTH WINDS CONTINUING OVERNIGHT INTO
WED...VFR CONDITIONS ARE EXPECTED TO PREVAIL.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 530 AM EDT TUE APR 9 2013
TODAY 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 INTO WED. NE WINDS COULD INCREASE TO GALES TO 35 KT WED NIGHT
INTO THU NIGHT 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...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...JLB
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
756 AM EDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A COUPLE OF WELL-DEFINED
SHORTWAVES LIFTING NORTH AND EAST...ONE THROUGH KS/NE AND ANOTHER
THROUGH CENTRAL IA. THESE SHORTWAVES ALONG WITH GOOD UPR DIV AND
800-700 MB FGEN AND 295K ISENTROPIC ASCENT IN RIGHT ENTRANCE REGION
OF 110+ KT 250 MB JET MAX OVER NORTHERN ONTARIO SUPPORTING BAND OF
RAIN NOW LIFTING NORTH INTO NE IA AND SRN WI PER LATEST REGIONAL
RADAR LOOP. QUIET OVER UPR MI EARLY THIS MORNING OTHER THAN SOME
PATCHY DENSE FOG DUE TO PERSISTENT LOW-LVL MOISTURE OVER THE AREA.
BAND OF RAIN OVER NE IA AND SRN WI IS EXPECTED TO LIFT GRADUALLY
NORTH AND EAST TODAY AS STRENGTHENING UPR JET NEAR ONTARIO/MN MOVES
EAST THROUGH ONTARIO TODAY AND INTO WRN QUEBEC THIS EVENING. MODELS
SHOW TRANSLATING UPR JET SUPPORT AND ASSOC 800-700 MB FGEN FORCING
AND 295K ISENTROPIC ASCENT ALLOWING PCPN BAND TO SHIFT NORTH AND
EAST TOWARD SCNTRL UPR MI LATER THIS AFTERNOON AND EVENING.
DEVELOPING DRY ANTICYCLONIC NE FLOW AHEAD OF HIGH PRES BUILDING IN
FM THE NRN PLAINS AND SCNTRL CANADA WILL IN TURN WORK TO PROVIDE A
SHARP CUTOFF TO NRN EXTENT OF PCPN. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET AND RAIN IS POSSIBLE LATER THIS AFTERNOON OVER THE
SOUTHERN TIER OF UPR MI. PTYPE WILL BE LIKELY ALL RAIN OVER THE SRN
HALF OF MNM COUNTY WHERE SFC TEMPS CLIMB INTO THE UPPER 30S AND
LOWER 40S.
TONIGHT...FCST SNDGS SUGGEST PTYPES WILL LIKELY BE A MIX
OF SNOW AND SLEET FOR AREAS MAINLY SOUTH OF A LINE FROM IRON
MOUNTAIN TO MANISTIQUE. BEST CHC OF PCPN WILL BE NEAR MNM WHERE
LIKELY POPS WILL BE UTILIZED FOR A MIX OF SNOW/SLEET MIXTURE AND
POSSIBLE ACCUMULATION OF AROUND AN INCH. AGAIN EXPECT A SHARP CUTOFF
OF PCPN TO THE NORTH AS DRY NE FLOW PERSISTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 741 AM EDT TUE APR 9 2013
EXPECT LIFR/VLIFR CONDITIONS TO LIFT TO MVFR BY LATE MORNING WITH
WEAK DIURNAL HEATING AND DRIER AIR WORKING IN FROM THE NORTH.
CONDITIONS SHOULD IMPROVE TO VFR AT KCMX BY LATE AFTERNOON IN
DOWNSLOPE NE FLOW THERE. NE FLOW WILL LIKELY KEEP MVFR CONDITIONS
GOING TONIGHT OVER KIWD AND KSAW.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 530 AM EDT TUE APR 9 2013
TODAY 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 INTO WED. NE WINDS COULD INCREASE TO GALES TO 35 KT WED NIGHT
INTO THU NIGHT 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...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...VOSS
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
530 AM EDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 530 AM EDT TUE APR 9 2013
WV IMAGERY AND RUC ANALYSIS INDICATED A COUPLE OF WELL-DEFINED
SHORTWAVES LIFTING NORTH AND EAST...ONE THROUGH KS/NE AND ANOTHER
THROUGH CENTRAL IA. THESE SHORTWAVES ALONG WITH GOOD UPR DIV AND
800-700 MB FGEN AND 295K ISENTROPIC ASCENT IN RIGHT ENTRANCE REGION
OF 110+ KT 250 MB JET MAX OVER NORTHERN ONTARIO SUPPORTING BAND OF
RAIN NOW LIFTING NORTH INTO NE IA AND SRN WI PER LATEST REGIONAL
RADAR LOOP. QUIET OVER UPR MI EARLY THIS MORNING OTHER THAN SOME
PATCHY DENSE FOG DUE TO PERSISTENT LOW-LVL MOISTURE OVER THE AREA.
BAND OF RAIN OVER NE IA AND SRN WI IS EXPECTED TO LIFT GRADUALLY
NORTH AND EAST TODAY AS STRENGTHENING UPR JET NEAR ONTARIO/MN MOVES
EAST THROUGH ONTARIO TODAY AND INTO WRN QUEBEC THIS EVENING. MODELS
SHOW TRANSLATING UPR JET SUPPORT AND ASSOC 800-700 MB FGEN FORCING
AND 295K ISENTROPIC ASCENT ALLOWING PCPN BAND TO SHIFT NORTH AND
EAST TOWARD SCNTRL UPR MI LATER THIS AFTERNOON AND EVENING.
DEVELOPING DRY ANTICYCLONIC NE FLOW AHEAD OF HIGH PRES BUILDING IN
FM THE NRN PLAINS AND SCNTRL CANADA WILL IN TURN WORK TO PROVIDE A
SHARP CUTOFF TO NRN EXTENT OF PCPN. THERMAL PROFILES SUGGEST THAT A
MIX OF SNOW/SLEET AND RAIN IS POSSIBLE LATER THIS AFTERNOON OVER THE
SOUTHERN TIER OF UPR MI. PTYPE WILL BE LIKELY ALL RAIN OVER THE SRN
HALF OF MNM COUNTY WHERE SFC TEMPS CLIMB INTO THE UPPER 30S AND
LOWER 40S.
TONIGHT...FCST SNDGS SUGGEST PTYPES WILL LIKELY BE A MIX
OF SNOW AND SLEET FOR AREAS MAINLY SOUTH OF A LINE FROM IRON
MOUNTAIN TO MANISTIQUE. BEST CHC OF PCPN WILL BE NEAR MNM WHERE
LIKELY POPS WILL BE UTILIZED FOR A MIX OF SNOW/SLEET MIXTURE AND
POSSIBLE ACCUMUMULATION OF AROUND AN INCH. AGAIN EXPECT A SHARP
CUTOFF OF PCPN TO THE NORTH AS DRY NE FLOW PERSISTS.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 152 AM EDT TUE APR 9 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
IFR/LIFR CONDITIONS TO 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 AND REMAIN THAT WAY THROUGH TUE EVENING. AT
SAW...LOW LEVEL MOISTURE WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO
KEEP THE LOW CIGS IN THROUGHOUT THE TAF PD ALTHOUGH CIGS SHOULD RISE
TO MVFR BY LATE TUE MORNING WITH SFC HEATING OF THE DAY.
&&
.MARINE...(FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)
ISSUED AT 530 AM EDT TUE APR 9 2013
TODAY 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 INTO WED. NE WINDS COULD INCREASE TO GALES TO 35 KT WED NIGHT
INTO THU NIGHT 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...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SHORT TERM...VOSS
LONG TERM...SRF
AVIATION...07
MARINE...VOSS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 AM EDT TUE APR 9 2013
.UPDATE...
ISSUED AT 901 PM EDT MON APR 8 2013
LOW LEVEL MOISTURE WILL CONTINUE TO REMAIN TRAPPED AS PRECIPITATION
HAS JUST ABOUT ENDED. THIS HAS CAUSED AREAS OF DENSE FOG TO FORM
OVER THE HIGHLANDS OF WESTERN UPPER MICHIGAN WITH VISIBILITIES BELOW
ONE QUARTER MILE. CONDITIONS WILL NOT IMPROVE OVERNIGHT AND ISSUED A
DENSE FOG ADVISORY FOR THIS ACROSS THE FAR WEST AND NORTH CENTRAL
COUNTIES. UPSLOPE WINDS OUT OF THE NORTH TO NORTHWEST WILL CONTINUE
TO BRING IN LOW LEVEL MOISTURE FROM LAKE SUPERIOR ALSO.
&&
.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...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 408 AM EDT TUE APR 9 2013
ACTIVE LONG TERM FORECAST CONTINUES...WITH SUBTLE MODEL DIFFERENCES
POTENTIALLY HAVING A LARGE IMPACT ON THE WEATHER. ALL OF THE WEATHER
FOR THE REST OF THE WORK WEEK DEPENDS ON THE LARGE UPPER TROUGH
CURRENTLY LOCATED OVER THE WESTERN CONUS AND HIGH PRESSURE CURRENTLY
LOCATED IN SOUTHERN ALBERTA/SASKATCHEWAN THAT IS EXPECTED TO PUSH A
RIDGE EAST OVER THE NORTHERN PART OF THE UPPER GREAT LAKES TONIGHT.
ONE OF THE MANY PIECES OF SHORTWAVE ENERGY EJECTING FROM THE UPPER
TROUGH WILL BE MOVING NORTHEAST THROUGH SOUTHERN WISCONSIN AND INTO
LOWER MICHIGAN ON WEDNESDAY. MODELS STILL DIFFERING SLIGHTLY ON THE
TRACK OF THE SHORTWAVE AND WHEN COMBINING THAT WITH THE NORTHERLY
FLOW OF DRY AIR FROM THE HIGH PRESSURE RIDGE OVER NORTHERN LAKE
SUPERIOR AND SOUTHERN ONTARIO...THERE IS EXPECTED TO BE A SHARP
NORTH TO SOUTH GRADIENT TO THE PRECIPITATION. AS FOR THE SYNOPTIC
PRECIPITATION...MODELS SEEM TO HAVE COME INTO A GOOD AGREEMENT ON
THE GENERAL NORTHERN EDGE OF THE PRECIPITATION TO BE FROM IRON RIVER
EAST TO MANISTIQUE...WITH THE HIGHEST POTENTIAL OF QPF IN THE
0.1-0.25 RANGE OVER FAR SOUTHERN MENOMINEE COUNTY DURING THE
MORNING. WILL FOLLOW THAT IDEA FOR POP/QPF...WHICH COMPARES WELL
WITH HPC VALUES. P-TYPE IS A LITTLE TRICKY...SINCE THERE IS A FAIRLY
ELEVATED WARM LAYER ALOFT /TOWARDS 750MB/...BUT DIFFERENCES IN THE
MODELS ON HOW WARM IT WILL BE. PLUS...THEY DIFFER ON IF THERE WILL
BE ENOUGH COLD AIR ABOVE THAT TO LEAD TO ANY ICE CRYSTALS IN THE
CLOUD. THUS...IT WILL PROBABLY BE LIQUID OR A PARTIALLY MIXED
LIQUID/ICE FALLING INTO THE COLDER CLOUD LAYER /TO -5C AT 875MB/
AIDED BY THE NORTHEASTERLY LOW LEVEL FLOW. THUS...USING THE TOP DOWN
METHODOLOGY...IT IS BORDERLINE FOR BEING COLD ENOUGH FOR SLEET
FORMATION AND MAY END UP FALLING AS RAIN. THUS...P-TYPE COMES DOWN
TO SURFACE TEMPERATURES...WHICH LOOK TO BE RIGHT AROUND FREEZING.
WITH ICE LIKELY STILL COVERING THE SOUTHERN HALF OF THE BAY OF GREEN
BAY...THERE PROBABLY WON/T BE ANY HELP FROM LAKE MICHIGAN. ALL IN
ALL...A VERY TRICKY P-TYPE AND WILL MENTION RAIN/SLEET AND FREEZING
RAIN OVER THE SOUTH CENTRAL AND TRENDING TOWARDS SNOW QUICKLY TO THE
NORTH. ELSEWHERE...EXPECT MAINLY CLOUDY SKIES WITH MID CLOUDS OVER
THE AREA AND A SHALLOW POCKET MOISTURE/CLOUDS AROUND 1KFT...WITH
850-700MB DRY AIR IN BETWEEN FROM THE HIGH PRESSURE RIDGE. WENT
TOWARDS A DRIER TREND FOR WEDNESDAY AFTERNOON INTO THE EARLY
EVENING. WEDNESDAY NIGHT NIGHT LOOKS TO BE MORE OF THE SAME...WITH
ANOTHER WEAK PIECE OF ENERGY BRUSHES THE SOUTHERN PART OF THE AREA
AND THE UPPER LOW MOVES EAST OUT OF THE CENTRAL PLAINS. BUT WITH THE
UPPER LOW GETTING CLOSER TO THE AREA...HAVE SLOWLY TRENDED POPS
NORTH THROUGH THE NIGHT.
THE GREATEST QUESTION FOR THE FORECAST WILL BE FOR THURSDAY INTO
FRIDAY AND HOW THE SOUTHERN STREAM UPPER TROUGH INTERACTS WITH
THE UPPER LOW IN QUEBEC AND SECONDARY SHORTWAVE SWINGING
OUT OF THE SOUTHERN PLAINS. THIS HAS CAUSED THE GREATEST
DISCREPANCIES OVER THE LAST 24HRS...LARGELY WITH THE LOW BEING
FARTHER SOUTHEAST AND THROUGH THE LOWER GREAT LAKES OR DRIFTING
FARTHER NORTHWEST AND MORE THROUGH THE UPPER GREAT LAKES. THE 08/00Z
RUN OF THE ECMWF WAS THE FIRST TO MAKE THIS TRANSITION...THEN THE
08/06Z RUN OF THE GFS STARTED THAT WAY TOO. THOSE TWO MODELS ARE
STILL THE MAIN ONES SHOWING THAT IDEA...WITH THE GEM/UKMET/NAVGEM
STARTING TO TREND IN THAT DIRECTION. DUE TO THE FAIRLY DECENT
QPF/SNOWFALL THAT IS POSSIBLE /OVER 1IN OF QPF ON THE ECMWF WHICH
WOULD POTENTIALLY PRODUCE A FOOT OF SNOW IN SOME PLACES/...ALONG
WITH THE BETTER LONG TERM VERIFICATION OF THE ECMWF...WILL TREND
TOWARDS THAT IDEA AND KEEP THE HIGHER POPS FOR THURSDAY AFTERNOON
AND TREND POPS UP INTO THURSDAY NIGHT. IF THE 12Z ECMWF SOLUTION IS
CORRECT...THE SNOW WILL CONTINUE INTO FRIDAY AND FRIDAY NIGHT WITH
LAKE ENHANCEMENT HELPING TO BOOST TOTALS NEAR LAKE SUPERIOR.
MEANWHILE...THE 00Z GFS SHIFTS THINGS OUT MUCH FASTER AS IT MERGES
WITH THE NORTHERN UPPER LOW AND PUSHES HIGH PRESSURE INTO THE AREA.
BUT WITH 850MB TEMPS STILL EXPECTED TO BE IN THE -10C RANGE...SOME
LIGHT LAKE ENHANCED/EFFECT PRECIPITATION WILL BE POSSIBLE IN THE
NORTHERLY WIND BELTS. WITH THE DIFFERENCES HEADING INTO THE
WEEKEND...WILL GO MORE TOWARDS A GENERAL BLEND OF THE MODELS FOR
POPS...BUT LEAN A LITTLE MORE TOWARDS THE ECMWF.
THE SYSTEM SHOULD SHIFT OUT OF THE AREA ON SATURDAY NIGHT AND LEAVE
A WEAK AREA OF HIGH PRESSURE FOR SUNDAY MORNING...BUT ATTENTION
THEN TURNS TO THE NEXT PIECE OF ENERGY EXITING THE PACIFIC
NORTHWEST AND MOVING THROUGH THE UPPER MISSISSIPPI VALLEY OR UPPER
GREAT LAKES ON SUNDAY AFTERNOON AND INTO MONDAY. LOW TRACK VARIES
FROM ACROSS UPPER MICHIGAN OR NORTHERN MN...WHICH MAKES A LARGE
DIFFERENCE ON TEMPS/P-TYPE/ETC. SO WILL GO HIGH END CHANCE POPS
FOR NOW AND AVERAGE THE THICKNESS FIELDS FOR P-TYPE. AT THIS
TIME...A GENERAL ADVISORY SNOWFALL IS POSSIBLE ON SUNDAY
BEFORE THE RAIN ARRIVES. THERE ARE HINTS THAT ANOTHER WAVE WILL BE
ENTERING THE PACIFIC NORTHWEST ON MONDAY...WHICH MAY AMPLIFY THE
WESTERN CONUS TROUGH AND LEAD TO ANOTHER ACTIVE WEEK NEXT WEEK.
THE BELOW NORMAL HIGH TEMPERATURES WILL CONTINUE THROUGH MUCH OF
THE LONG TERM PERIOD AND WILL GENERALLY BE IN THE 30S. THURSDAY WILL
FEEL LIKE WINTER WITH THE SNOW...ESPECIALLY NEAR LAKE SUPERIOR WHERE
NORTHEST WINDS GUSTING TO 25-35MPH WILL PUSH WIND CHILLS INTO THE
UPPER SINGLE DIGITS OR LOWER TEENS AND LEAD TO BLOWING SNOW. THE
BEST CHANCE FOR SEEING 40 DEGREES ACROSS THE AREA WILL BE ON
SUNDAY/MONDAY AS THE NEXT LOW PRESSURE SYSTEM PULLS WARMER AIR
NORTH TOWARDS THE AREA.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 152 AM EDT TUE APR 9 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
IFR/LIFR CONDITIONS TO 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 AND REMAIN THAT WAY THROUGH TUE EVENING. AT
SAW...LOW LEVEL MOISTURE WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO
KEEP THE LOW CIGS IN THROUGHOUT THE TAF PD ALTHOUGH CIGS SHOULD RISE
TO MVFR BY LATE TUE MORNING WITH SFC HEATING OF THE DAY.
&&
.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.
&&
$$
UPDATE...07
SHORT TERM...JLB
LONG TERM...SRF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
156 AM EDT TUE APR 9 2013
.UPDATE...
ISSUED AT 901 PM EDT MON APR 8 2013
LOW LEVEL MOISTURE WILL CONTINUE TO REMAIN TRAPPED AS PRECIPITATION
HAS JUST ABOUT ENDED. THIS HAS CAUSED AREAS OF DENSE FOG TO FORM
OVER THE HIGHLANDS OF WESTERN UPPER MICHIGAN WITH VISIBILITIES BELOW
ONE QUARTER MILE. CONDITIONS WILL NOT IMPROVE OVERNIGHT AND ISSUED A
DENSE FOG ADVISORY FOR THIS ACROSS THE FAR WEST AND NORTH CENTRAL
COUNTIES. UPSLOPE WINDS OUT OF THE NORTH TO NORTHWEST WILL CONTINUE
TO BRING IN LOW LEVEL MOISTURE FROM LAKE SUPERIOR ALSO.
&&
.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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 152 AM EDT TUE APR 9 2013
WITH PLENTY OF LOW LEVEL MOISTURE IN PLACE AND UPSLOPE FLOW...EXPECT
IFR/LIFR CONDITIONS TO 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 AND REMAIN THAT WAY THROUGH TUE EVENING. AT
SAW...LOW LEVEL MOISTURE WILL LINGER ALONG WITH UPSLOPE CONDITIONS TO
KEEP THE LOW CIGS IN THROUGHOUT THE TAF PD ALTHOUGH CIGS SHOULD RISE
TO MVFR BY LATE TUE MORNING WITH SFC HEATING OF THE DAY.
&&
.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...
DENSE FOG ADVISORY UNTIL 8 AM EDT /7 AM CDT/ THIS MORNING FOR
MIZ001>005-009-084.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
UPDATE...07
SHORT TERM...JLB
LONG TERM...KF
AVIATION...07
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS TWIN CITIES/CHANHASSEN MN
136 PM CDT TUE APR 9 2013
.UPDATE...
18Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
SIGNIFICANT SPRING SYSTEM IN FULL SWING ACROSS THE MID SECTION OF
THE COUNTRY THIS MORNING AND WILL MAKE FOR AN INCREDIBLY COMPLEX
WEATHER SCENARIO TODAY AND TONIGHT.
WATER VAPOR IMAGERY THIS MORNING SHOWS A MATURE AND DEEP LOW OVER
THE FOUR CORNERS AREA. EAST OF THIS UPPER TROUGH...A DEEP LEE
CYCLONE THAT WAS SUB 995 MB WAS EXITING SE COLORADO. WITH A 1035 MB
HIGH WORKING SOUTH OUT OF ALBERTA...A STRONG ARCTIC FRONT WAS TAKING
SHAPE FROM THE SFC LOW NORTHEAST TO JUST SOUTH OF THE I-80 CORRIDOR
IN IOWA. NORTH OF THIS BOUNDARY...THERE IS STRONG UPPER DIFFLUENCE
ACROSS SODAK/NEB/IA AS THE NORTHERN PLAINS SITS AN INCREASINGLY
COUPLED JET REGION BETWEEN A ZONAL JET SITUATED ALONG THE 49TH
PARALLEL FROM NODAK ON EAST AND A SW JET STREAK THAT IS CURRENTLY
ROUNDING THE BASE OF THE WESTERN TROUGH. THIS UPPER DIFFLUENCE IS
BEING AIDED BY A 40-50 KT LLJ THAT IS RUNNING UP INTO THE FRONTAL
REGION.
FOR TODAY...THE RAP SHOWS THIS LLJ WEAKENING THIS MORNING AS IT
SLIDES EAST. OVER THE MPX AREA...WE WILL BE SEEING A STRONG ERLY
COLD CONVEYOR BELT STRENGTHENING DURING THE DAY TODAY. THIS WILL
KEEP THE THUNDER ACROSS NEB/IA MAINLY SOUTH OF US...BUT PRECIP
SHIELD ASSOCIATED WITH COUPLED JET STRUCTURE WILL PUSH AN AREA OF
PRECIP INTO SW MN SHORTLY THAT WILL LIFT E/NE UP TO AT LEAST THE
I-94 CORRIDOR THIS MORNING. MAIN QUESTION FOR TODAY WAS HOW FAR
NORTH DOES THE PRECIP MAKE IT...AS NNE LOW LEVEL FLOW WILL BE
ADVECTING SOME DRIER AIR IN THAT WILL LEAD TO A SHARP CUT OFF IN
PRECIP ACROSS CENTRAL MN/NW WI. WITH THE ERLY LLJ ASSOCIATED WITH
THE COLD CONVEYOR BELT REMAINING PARKED OVER THE AREA THROUGH
TONIGHT /AND REALLY IT WILL BE WITH US ALL THE WAY INTO
THURSDAY/...WILL SEE SEVERAL ROUNDS OF PRECIP MOVE ACROSS THE
AREA...WITH A RATHER WET SHORT TERM PERIOD EXPECTED.
BIGGER PROBLEM THOUGH IN THE SHORT TERM IS WHAT HAPPENS WITH P-TYPE
THROUGH TONIGHT. WITH THE COLD CONVEYOR BELT DEVELOPING TODAY...WILL
SEE STRONG CAA COMMENCE BELOW 800 MB...WHICH WILL START COOLING THIS
LAYER TO BELOW FREEZING TODAY INTO TONIGHT. HOWEVER...AS THIS IS
GOING ON FORECAST SOUNDINGS FROM THE RAP/NAM/GFS..SHOW WAA IN THE
H8-H7 LAYER RESULTING IS A RATHER STUBBORN MELTING LAYER SETTING UP
THERE. THE BIG QUESTION FOR THE SHORT TERM...IS HOW QUICKLY DOES
THIS WARM NOSE BREAK DOWN. WHEN THIS WARM NOSE IS IN PLACE...SHOULD
SEE A WINTRY MIX THAT IS DOMINATED BY SLEET...WITH SOME FZRA OR RA
DEPENDING ON SFC TEMPS. THE REASON FOR SLEET BEING THE DOMINATE
P-TYPE WHEN THE MELTING LAYER IS PRESENT IS THAT THE FREEZING LAYER
BELOW IT LOOKS TO BE NEARLY 5K FT DEEP...WITH A MIN TEMP AROUND
-5C...BOTH MORE THAN ADEQUATE TO CREATE MAINLY SLEET. ONCE THIS WARM
NOSE COOLS BELOW FREEZING...ITS OFF TO A HEAVY WET SNOW. THE ECMWF
CONTINUES TO BE THE SLOWEST IN BREAKING DOWN THIS WARM LAYER
/RESULTING IN THE LEAST AMOUNT OF SNOW/...WHILE THE GFS/NAM ARE
SIMILAR AND CONVERT THINGS TO SNOW CONSIDERABLY FASTER...SETTING UP
THE POTENTIAL FOR SOME SNOWFALL AMOUNTS GREATER THAN A
FOOT...ESPECIALLY IN WRN MN. IN THE GRIDS...TRIED BLENDING BETWEEN
THE ECMWF AND NCEP MODELS AS MUCH AS POSSIBLE...BUT CERTAINLY THINK
MORE REFINEMENTS WILL BE NEEDED GOING FORWARD.
AS FOR HEADLINES...UPGRADED PART OF THE WATCH TO A WARNING...
INCLUDING THE TWIN CITIES METRO...GIVEN THE POTENTIAL FOR THE
PL/FZRA MIX TONIGHT...FOLLOWED BY THE POTENTIAL FOR 6-8+ INCHES OF
SNOW TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. CONVERTED NRN TIER OF
COUNTIES TO AN ADVY SINCE THERE ARE QUESTIONS AS TO JUST HOW MUCH
PRECIPITATION REACHES THAT FAR NORTH. ALSO ADDED A COUPLE ROWS OF
BUFFER COUNTIES TO THE ADVY SOUTH OF THE WARNING...WITH MORE RAIN
ISSUES EXPECTED HERE. ALSO EXTENDED THAT ADVY ACROSS THE WI
COUNTIES...MAINLY FOR THE PL/FZRA THREAT TONIGHT. WITH THE SLOWNESS
OF THE ECMWF WITH BREAKING DOWN THE WARM NOSE ACROSS ERN AREAS...DID
NOT FEEL CONFIDENT WITH EXTENDING A WARNING INTO WI...THOUGH IF IT
IS LOOKING LIKE THE NAM/GFS SOLN WILL WIN OUT...THEN THE WI ADVY
COULD EASILY BE UPGRADED TO A WARNING.
.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
BY WEDNESDAY MORNING...VERY DEEP 50H LONG WAVE TROUGH DIGGING DEEP
INTO THE CENTRAL PORTION OF OLD MEXICO. MID LEVEL LOW PRESSURE
FORMS OVER NE AND CENTRAL SODAK. BY WED/18Z MID LEVEL LOW
DEEPENS...WHILE SURFACE CYCLONE CONTINUES TO EJECT OUT FROM UNDER
THE 50H TROF INTO CENTRAL MO. LAST SLIVER OF -RA/-FZRA/IP OVER FAR
SE CWA FINALLY TRANSITIONS TO ALL SNOW BY LATE MORNING ON WED. USED
BUFKIT SOUNDING FOR TIMING OF SAME. REMAINDER OF PCPN ASSOCIATED
WITH STORM SYSTEM WILL BE SNOW. NAM CONTINUES TO GENERATE THE
HEALTHIEST AMOUNT OF QPF...WHEREAS EUROPEAN IS TRENDING TOWARD
THE LOWER END OF THE SPECTRUM. HAVE GRAVITATED TOWARD THE MIDDLE
GROUND...WITH A COMBO MOISTURE CONTENT SOMEWHERE BETWEEN THE GFS40
AND EUROPEAN. BEST 600MB DENDRITIC GROWTH VALUES BEGIN TO KICK
IN ACROSS WEST CENTRAL MN BY WEDNESDAY MORNING...AND REMAIN OVER
THIS REGION FOR BULK OF THE EVENT...FINALLY REACHING SOUTH CENTRAL
AND EAST CENTRAL MN BY EARLY THU AFTN.
WITH THAT SAID TOTAL FORECAST SNOWFALL FOR THE EVENT RANGES FROM
ABOUT 5 INCHES NORTH OF A LINE FROM ALEXANDRIA TO RICE LAKE WI. MUCH
OF THE REMAINDER OF THE CWA WILL INCUR BETWEEN 6 AND 10 INCHES OF
SNOW...WITH HEAVIEST AMOUNTS ANTICIPATED OVER SWIFT
...CHIPPEWA...LAC QUI PARLE AND YELLOW MEDICINE COUNTIES. OF COURSE
WITH BANDING EFFECTS SCATTERED SNOWFALL AMOUNTS NEAR 8 INCHES SHOULD
ALSO BE EXPECTED OVER PORTIONS OF WEST CENTRAL WISCONSIN. ALTHOUGH
HEAVY WATER CONTENT SNOWFALL WILL OCCUR ...MODERATE NORTHEASTERLY
FLOW WED AFTN INTO EARLY WED EVE COULD GENERATE SOME OCNL LOW END
DRIFTING. CLOSED 50H LOW WILL FINALLY EXIT WESTERN WI ON FRIDAY
MORNING. MAINLY FLURRY OR SNOW SHOWER ACTIVITY EXPECTED TO ITS
IMMEDIATE LEE ON FRIDAY MORNING.
ZONAL FLOW KICKS IN ACROSS MUCH OF NORTHERN US ON FRIDAY NIGHT
AND CONTINUES INTO THE WEEKEND. THIS WILL UNDOUBTEDLY ALMOST
GUARANTEE AT LEAST MOSTLY CLOUDY CONDITIONS ACROSS THE REGION
INTO MONDAY. ZONAL FLOW WILL ALSO USHER IN A NEW HYBRID EARLY
SPRING STORM SYSTEM BY SATURDAY NIGHT. FORTUNATELY FOR FLOODING
CONCERNS THIS SYSTEM WILL NOT PRODUCE AS MUCH MOISTURE NOR
LAST AS LONG AS THE MID WEEK SYSTEM. IT ALSO APPEARS AT THIS
JUNCTURE THAT ENOUGH WARM AIR WILL BE IN PLACE TO GENERATE
MORE OF A RAIN/SNOW OR RAIN EVENT AS BULK OF STORM SYSTEM
VACATES REGION BY MONDAY MORNING. AFTER THAT ANOTHER LONG
WAVE TROUGH WILL DIG ACROSS THE PACIFIC NORTHWEST INTO NEXT
WEDNESDAY. TEMPERATURES WILL REMAIN ROUGHLY 10 DEGREES BELOW
NORMAL THROUGH MUCH OF THE NEXT 7 DAYS.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 122 PM CDT TUE APR 9 2013
TRICKY AVIATION FORECAST FOR THE NEXT 24 TO 30 HOURS AS MULTIPLE
ROUNDS OF PRECIP BRING DIFFERING TYPES OF WX AND CIGS/VSBYS.
CURRENTLY ANTICIPATE THE SNOW TYPE ALONG AND NORTHWEST OF RWF TO
STC TO BE IN THE FORM OF SNOW...WITH RAIN AND SOME SLEET MIXED TO
THE SOUTHEAST. A LULL THIS AFTERNOON WILL GIVE WAY TO ANOTHER
ROUND THIS EVENING AND PRECIP WILL TRANSITION TO MAINLY SNOW AT MSP/RNH
BETWEEN 04-06Z AND EAU AROUND 10Z. ANOTHER LULL IS EXPECTED
WEDNESDAY MORNING. CIGS ARE HIGHLY VARIABLE...RANGING FROM VFR TO
IFR...BUT AS THE PRECIP CONTINUES TO DIMINISH THIS AFTERNOON
EXPECT CIGS TO IMRPOVE A BIT.
KMSP...FRIST ROUND IS JUST ABOUT DONE WITH ONLY A FEW SHOWERS
LINGERING INTOT HE EARLY EVENING. ANOTHER ROUND WILL ARRIVE LATE
THIS EVENING AND SHOULD BE MOSTLY IN THE FORM OF SNOW...WITH
PERHAPS A LITTLE SLEET ALSO MIXING IN INITIALLY. MAINLY VFR
CIGS/VSBYS TODAY AND THIS EVENING WILL GIVE WAY TO MVFR/IFR
CONDITIONS WITH THE NEXT ROUND TONIGHT.
/OUTLOOK FOR KMSP/
WED...IFR WITH SN. NE WIND 15G25 KTS.
THU...MVFR OR LOWER CIGS/VIS WITH SN. NE WIND 15G12 KTS.
FRI...MVFR CIGS. -SN ENDING IN MORNING. WINDS NW WIND 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
THURSDAY FOR MNZ041>045-050-074>077-082>085.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR MNZ047>049-
054>058-064-065-073.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM CDT THURSDAY
FOR MNZ051>053-059>063-066>070.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR MNZ078.
WI...WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR WIZ014>016-023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...BORGHOFF
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
724 AM CDT TUE APR 9 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY THROUGH TONIGHT)
SIGNIFICANT SPRING SYSTEM IN FULL SWING ACROSS THE MID SECTION OF
THE COUNTRY THIS MORNING AND WILL MAKE FOR AN INCREDIBLY COMPLEX
WEATHER SCENARIO TODAY AND TONIGHT.
WATER VAPOR IMAGERY THIS MORNING SHOWS A MATURE AND DEEP LOW OVER
THE FOUR CORNERS AREA. EAST OF THIS UPPER TROUGH...A DEEP LEE
CYCLONE THAT WAS SUB 995 MB WAS EXITING SE COLORADO. WITH A 1035 MB
HIGH WORKING SOUTH OUT OF ALBERTA...A STRONG ARCTIC FRONT WAS TAKING
SHAPE FROM THE SFC LOW NORTHEAST TO JUST SOUTH OF THE I-80 CORRIDOR
IN IOWA. NORTH OF THIS BOUNDARY...THERE IS STRONG UPPER DIFFLUENCE
ACROSS SODAK/NEB/IA AS THE NORTHERN PLAINS SITS AN INCREASINGLY
COUPLED JET REGION BETWEEN A ZONAL JET SITUATED ALONG THE 49TH
PARALLEL FROM NODAK ON EAST AND A SW JET STREAK THAT IS CURRENTLY
ROUNDING THE BASE OF THE WESTERN TROUGH. THIS UPPER DIFFLUENCE IS
BEING AIDED BY A 40-50 KT LLJ THAT IS RUNNING UP INTO THE FRONTAL
REGION.
FOR TODAY...THE RAP SHOWS THIS LLJ WEAKENING THIS MORNING AS IT
SLIDES EAST. OVER THE MPX AREA...WE WILL BE SEEING A STRONG ERLY
COLD CONVEYOR BELT STRENGTHENING DURING THE DAY TODAY. THIS WILL
KEEP THE THUNDER ACROSS NEB/IA MAINLY SOUTH OF US...BUT PRECIP
SHIELD ASSOCIATED WITH COUPLED JET STRUCTURE WILL PUSH AN AREA OF
PRECIP INTO SW MN SHORTLY THAT WILL LIFT E/NE UP TO AT LEAST THE
I-94 CORRIDOR THIS MORNING. MAIN QUESTION FOR TODAY WAS HOW FAR
NORTH DOES THE PRECIP MAKE IT...AS NNE LOW LEVEL FLOW WILL BE
ADVECTING SOME DRIER AIR IN THAT WILL LEAD TO A SHARP CUT OFF IN
PRECIP ACROSS CENTRAL MN/NW WI. WITH THE ERLY LLJ ASSOCIATED WITH
THE COLD CONVEYOR BELT REMAINING PARKED OVER THE AREA THROUGH
TONIGHT /AND REALLY IT WILL BE WITH US ALL THE WAY INTO
THURSDAY/...WILL SEE SEVERAL ROUNDS OF PRECIP MOVE ACROSS THE
AREA...WITH A RATHER WET SHORT TERM PERIOD EXPECTED.
BIGGER PROBLEM THOUGH IN THE SHORT TERM IS WHAT HAPPENS WITH P-TYPE
THROUGH TONIGHT. WITH THE COLD CONVEYOR BELT DEVELOPING TODAY...WILL
SEE STRONG CAA COMMENCE BELOW 800 MB...WHICH WILL START COOLING THIS
LAYER TO BELOW FREEZING TODAY INTO TONIGHT. HOWEVER...AS THIS IS
GOING ON FORECAST SOUNDINGS FROM THE RAP/NAM/GFS..SHOW WAA IN THE
H8-H7 LAYER RESULTING IS A RATHER STUBBORN MELTING LAYER SETTING UP
THERE. THE BIG QUESTION FOR THE SHORT TERM...IS HOW QUICKLY DOES
THIS WARM NOSE BREAK DOWN. WHEN THIS WARM NOSE IS IN PLACE...SHOULD
SEE A WINTRY MIX THAT IS DOMINATED BY SLEET...WITH SOME FZRA OR RA
DEPENDING ON SFC TEMPS. THE REASON FOR SLEET BEING THE DOMINATE
P-TYPE WHEN THE MELTING LAYER IS PRESENT IS THAT THE FREEZING LAYER
BELOW IT LOOKS TO BE NEARLY 5K FT DEEP...WITH A MIN TEMP AROUND
-5C...BOTH MORE THAN ADEQUATE TO CREATE MAINLY SLEET. ONCE THIS WARM
NOSE COOLS BELOW FREEZING...ITS OFF TO A HEAVY WET SNOW. THE ECMWF
CONTINUES TO BE THE SLOWEST IN BREAKING DOWN THIS WARM LAYER
/RESULTING IN THE LEAST AMOUNT OF SNOW/...WHILE THE GFS/NAM ARE
SIMILAR AND CONVERT THINGS TO SNOW CONSIDERABLY FASTER...SETTING UP
THE POTENTIAL FOR SOME SNOWFALL AMOUNTS GREATER THAN A
FOOT...ESPECIALLY IN WRN MN. IN THE GRIDS...TRIED BLENDING BETWEEN
THE ECMWF AND NCEP MODELS AS MUCH AS POSSIBLE...BUT CERTAINLY THINK
MORE REFINEMENTS WILL BE NEEDED GOING FORWARD.
AS FOR HEADLINES...UPGRADED PART OF THE WATCH TO A WARNING...
INCLUDING THE TWIN CITIES METRO...GIVEN THE POTENTIAL FOR THE
PL/FZRA MIX TONIGHT...FOLLOWED BY THE POTENTIAL FOR 6-8+ INCHES OF
SNOW TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. CONVERTED NRN TIER OF
COUNTIES TO AN ADVY SINCE THERE ARE QUESTIONS AS TO JUST HOW MUCH
PRECIPITATION REACHES THAT FAR NORTH. ALSO ADDED A COUPLE ROWS OF
BUFFER COUNTIES TO THE ADVY SOUTH OF THE WARNING...WITH MORE RAIN
ISSUES EXPECTED HERE. ALSO EXTENDED THAT ADVY ACROSS THE WI
COUNTIES...MAINLY FOR THE PL/FZRA THREAT TONIGHT. WITH THE SLOWNESS
OF THE ECMWF WITH BREAKING DOWN THE WARM NOSE ACROSS ERN AREAS...DID
NOT FEEL CONFIDENT WITH EXTENDING A WARNING INTO WI...THOUGH IF IT
IS LOOKING LIKE THE NAM/GFS SOLN WILL WIN OUT...THEN THE WI ADVY
COULD EASILY BE UPGRADED TO A WARNING.
.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
BY WEDNESDAY MORNING...VERY DEEP 50H LONG WAVE TROUGH DIGGING DEEP
INTO THE CENTRAL PORTION OF OLD MEXICO. MID LEVEL LOW PRESSURE
FORMS OVER NE AND CENTRAL SODAK. BY WED/18Z MID LEVEL LOW
DEEPENS...WHILE SURFACE CYCLONE CONTINUES TO EJECT OUT FROM UNDER
THE 50H TROF INTO CENTRAL MO. LAST SLIVER OF -RA/-FZRA/IP OVER FAR
SE CWA FINALLY TRANSITIONS TO ALL SNOW BY LATE MORNING ON WED. USED
BUFKIT SOUNDING FOR TIMING OF SAME. REMAINDER OF PCPN ASSOCIATED
WITH STORM SYSTEM WILL BE SNOW. NAM CONTINUES TO GENERATE THE
HEALTHIEST AMOUNT OF QPF...WHEREAS EUROPEAN IS TRENDING TOWARD
THE LOWER END OF THE SPECTRUM. HAVE GRAVITATED TOWARD THE MIDDLE
GROUND...WITH A COMBO MOISTURE CONTENT SOMEWHERE BETWEEN THE GFS40
AND EUROPEAN. BEST 600MB DENDRITIC GROWTH VALUES BEGIN TO KICK
IN ACROSS WEST CENTRAL MN BY WEDNESDAY MORNING...AND REMAIN OVER
THIS REGION FOR BULK OF THE EVENT...FINALLY REACHING SOUTH CENTRAL
AND EAST CENTRAL MN BY EARLY THU AFTN.
WITH THAT SAID TOTAL FORECAST SNOWFALL FOR THE EVENT RANGES FROM
ABOUT 5 INCHES NORTH OF A LINE FROM ALEXANDRIA TO RICE LAKE WI. MUCH
OF THE REMAINDER OF THE CWA WILL INCUR BETWEEN 6 AND 10 INCHES OF
SNOW...WITH HEAVIEST AMOUNTS ANTICIPATED OVER SWIFT
...CHIPPEWA...LAC QUI PARLE AND YELLOW MEDICINE COUNTIES. OF COURSE
WITH BANDING EFFECTS SCATTERED SNOWFALL AMOUNTS NEAR 8 INCHES SHOULD
ALSO BE EXPECTED OVER PORTIONS OF WEST CENTRAL WISCONSIN. ALTHOUGH
HEAVY WATER CONTENT SNOWFALL WILL OCCUR ...MODERATE NORTHEASTERLY
FLOW WED AFTN INTO EARLY WED EVE COULD GENERATE SOME OCNL LOW END
DRIFTING. CLOSED 50H LOW WILL FINALLY EXIT WESTERN WI ON FRIDAY
MORNING. MAINLY FLURRY OR SNOW SHOWER ACTIVITY EXPECTED TO ITS
IMMEDIATE LEE ON FRIDAY MORNING.
ZONAL FLOW KICKS IN ACROSS MUCH OF NORTHERN US ON FRIDAY NIGHT
AND CONTINUES INTO THE WEEKEND. THIS WILL UNDOUBTEDLY ALMOST
GUARANTEE AT LEAST MOSTLY CLOUDY CONDITIONS ACROSS THE REGION
INTO MONDAY. ZONAL FLOW WILL ALSO USHER IN A NEW HYBRID EARLY
SPRING STORM SYSTEM BY SATURDAY NIGHT. FORTUNATELY FOR FLOODING
CONCERNS THIS SYSTEM WILL NOT PRODUCE AS MUCH MOISTURE NOR
LAST AS LONG AS THE MID WEEK SYSTEM. IT ALSO APPEARS AT THIS
JUNCTURE THAT ENOUGH WARM AIR WILL BE IN PLACE TO GENERATE
MORE OF A RAIN/SNOW OR RAIN EVENT AS BULK OF STORM SYSTEM
VACATES REGION BY MONDAY MORNING. AFTER THAT ANOTHER LONG
WAVE TROUGH WILL DIG ACROSS THE PACIFIC NORTHWEST INTO NEXT
WEDNESDAY. TEMPERATURES WILL REMAIN ROUGHLY 10 DEGREES BELOW
NORMAL THROUGH MUCH OF THE NEXT 7 DAYS.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 724 CDT TUE APR 9 2013
PRECIPITATION BEGINNING TO SPREAD NORTH TOWARD MPX TERMINALS AS
PROLONGED PRECIPITATION EVENT THAT WILL LAST THROUGH THURSDAY IS
STARTING TO GET GOING. SEEING AN INTERESTING BATTLE BETWEEN MOIST
AIR SOUTH AND DRY AIR NORTH...WITH VFR CONDS SEEN AT AXN AND VERY
CLOSE TO STC. THIS DRY AIR HAS HELPED HOLD UP ADVANCEMENT OF IFR
CIGS...BUT AS MORE WIDESPREAD PRECIP OVERSPREADS THE AREA...CIGS
SHOULD QUICKLY FALL INTO THE IFR RANGE THIS MORNING AND MAY VERY
WELL STAY FIRMLY PLANTED THERE THROUGH MUCH OF THURSDAY. TIMED
INITIAL WAVE OF PRECIP ON THE HRRR...BUT KEPT IT OUT OF AXN PER
THE GFS WITH DRY AIR DOING A SIGNIFICANT NUMBER TO MOISTURE
PROFILES ACROSS CENTRAL MN. WILL SEE SEVERAL WAVES OF PRECIP OVER
THE NEXT FEW DAYS AND FOLLOWED THE IDEA OF THE RAP AND NAM AND
OTHER HIGH-RES MODELS WITH A BRIEF LULL IN PRECIP THIS EVENING
BEFORE ANOTHER WAVE OF PRECIP MOVES IN THIS TONIGHT. THOUGH THE
ENTIRE DAY WILL NOT BE FILLED WITH PRECIP...DRY PERIODS SHOULD BE
FAR OUTNUMBERED BY WET PERIODS. P-TYPE ALSO TOUGH AS WELL...WITH
SIGNIFICANT DISAGREEMENTS BETWEEN THE RAP AND NAM IN TERMS OF
P-TYPE. BASED ON CURRENT CONDITIONS...THE RAP LOOKS TO BE RUNNING
WARM...SO FOLLOWED THE NAM FOR P-TYPE. STILL LOOKS GOOD FOR A
PROLONGED PERIOD OF MIXED PRECIP OUTSIDE OF AXN...AND BASED ON
DEPTH OF SUB-FREEZING LAYER...PREDOMINATE P-TYPE LOOKS TO BE SLEET
UNTIL THE WARM NOSE AROUND 6K FT ABOVE THE GROUND CAN BE BEAT
BACK. FOR AS CHAOTIC AS THE WX/CIG/VIS WILL BE...WINDS WILL FAIRLY
UNIFORM THIS PERIOD OUT BETWEEN 010 AND 040.
KMSP...FOR CIGS...WITH DRIER NE WINDS...MAY SEE CIGS GO ABOVE
1700 FT UNTIL STEADIER RAIN ARRIVES AROUND 14Z. AFTER THAT...WILL
SPEND A LONG DURATION OF TIME WITH CIGS UNDER 1700 FT. BASED ON
THE RAP/NAM...EXPECT A BREAK IN THE STEADY PRECIP BETWEEN ABOUT
21Z AND 6Z...BEFORE ANOTHER BATCH OF MORE PERSISTENT PRECIP MOVES
IN. CONFIDENCE HIGH IN A P-TYPE OF RAIN TODAY. A TRANSITION TO
SLEET IS EXPECTED THIS EVENING BETWEEN 3 AND 6Z...AND BASED ON
CURRENT NAM BUFKIT SOUNDINGS...MSP MAY SPEND CLOSE TO THE NEXT 24
HOURS WITH SLEET OR A SLEET/RAIN MIX BEFORE FINALLY SWITCHING TO
SNOW WEDNESDAY NIGHT.
/OUTLOOK FOR KMSP/
WED...IFR WITH SN. NE WIND 15G25 KTS.
THU...MVFR OR LOWER CIGS/VIS WITH SN. NE WIND 15G12 KTS.
FRI...MVFR CIGS. -SN ENDING IN MORNING. WINDS NW WIND 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
THURSDAY FOR MNZ041>045-050-074>077-082>085.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR MNZ047>049-
054>058-064-065-073.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM CDT THURSDAY
FOR MNZ051>053-059>063-066>070.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR MNZ078.
WI...WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR WIZ014>016-023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
414 AM CDT TUE APR 9 2013
.SHORT TERM...(TODAY THROUGH TONIGHT)
SIGNIFICANT SPRING SYSTEM IN FULL SWING ACROSS THE MID SECTION OF
THE COUNTRY THIS MORNING AND WILL MAKE FOR AN INCREDIBLY COMPLEX
WEATHER SCENARIO TODAY AND TONIGHT.
WATER VAPOR IMAGERY THIS MORNING SHOWS A MATURE AND DEEP LOW OVER
THE FOUR CORNERS AREA. EAST OF THIS UPPER TROUGH...A DEEP LEE
CYCLONE THAT WAS SUB 995 MB WAS EXITING SE COLORADO. WITH A 1035 MB
HIGH WORKING SOUTH OUT OF ALBERTA...A STRONG ARCTIC FRONT WAS TAKING
SHAPE FROM THE SFC LOW NORTHEAST TO JUST SOUTH OF THE I-80 CORRIDOR
IN IOWA. NORTH OF THIS BOUNDARY...THERE IS STRONG UPPER DIFFLUENCE
ACROSS SODAK/NEB/IA AS THE NORTHERN PLAINS SITS AN INCREASINGLY
COUPLED JET REGION BETWEEN A ZONAL JET SITUATED ALONG THE 49TH
PARALLEL FROM NODAK ON EAST AND A SW JET STREAK THAT IS CURRENTLY
ROUNDING THE BASE OF THE WESTERN TROUGH. THIS UPPER DIFFLUENCE IS
BEING AIDED BY A 40-50 KT LLJ THAT IS RUNNING UP INTO THE FRONTAL
REGION.
FOR TODAY...THE RAP SHOWS THIS LLJ WEAKENING THIS MORNING AS IT
SLIDES EAST. OVER THE MPX AREA...WE WILL BE SEEING A STRONG ERLY
COLD CONVEYOR BELT STRENGTHENING DURING THE DAY TODAY. THIS WILL
KEEP THE THUNDER ACROSS NEB/IA MAINLY SOUTH OF US...BUT PRECIP
SHIELD ASSOCIATED WITH COUPLED JET STRUCTURE WILL PUSH AN AREA OF
PRECIP INTO SW MN SHORTLY THAT WILL LIFT E/NE UP TO AT LEAST THE
I-94 CORRIDOR THIS MORNING. MAIN QUESTION FOR TODAY WAS HOW FAR
NORTH DOES THE PRECIP MAKE IT...AS NNE LOW LEVEL FLOW WILL BE
ADVECTING SOME DRIER AIR IN THAT WILL LEAD TO A SHARP CUT OFF IN
PRECIP ACROSS CENTRAL MN/NW WI. WITH THE ERLY LLJ ASSOCIATED WITH
THE COLD CONVEYOR BELT REMAINING PARKED OVER THE AREA THROUGH
TONIGHT /AND REALLY IT WILL BE WITH US ALL THE WAY INTO
THURSDAY/...WILL SEE SEVERAL ROUNDS OF PRECIP MOVE ACROSS THE
AREA...WITH A RATHER WET SHORT TERM PERIOD EXPECTED.
BIGGER PROBLEM THOUGH IN THE SHORT TERM IS WHAT HAPPENS WITH P-TYPE
THROUGH TONIGHT. WITH THE COLD CONVEYOR BELT DEVELOPING TODAY...WILL
SEE STRONG CAA COMMENCE BELOW 800 MB...WHICH WILL START COOLING THIS
LAYER TO BELOW FREEZING TODAY INTO TONIGHT. HOWEVER...AS THIS IS
GOING ON FORECAST SOUNDINGS FROM THE RAP/NAM/GFS..SHOW WAA IN THE
H8-H7 LAYER RESULTING IS A RATHER STUBBORN MELTING LAYER SETTING UP
THERE. THE BIG QUESTION FOR THE SHORT TERM...IS HOW QUICKLY DOES
THIS WARM NOSE BREAK DOWN. WHEN THIS WARM NOSE IS IN PLACE...SHOULD
SEE A WINTRY MIX THAT IS DOMINATED BY SLEET...WITH SOME FZRA OR RA
DEPENDING ON SFC TEMPS. THE REASON FOR SLEET BEING THE DOMINATE
P-TYPE WHEN THE MELTING LAYER IS PRESENT IS THAT THE FREEZING LAYER
BELOW IT LOOKS TO BE NEARLY 5K FT DEEP...WITH A MIN TEMP AROUND
-5C...BOTH MORE THAN ADEQUATE TO CREATE MAINLY SLEET. ONCE THIS WARM
NOSE COOLS BELOW FREEZING...ITS OFF TO A HEAVY WET SNOW. THE ECMWF
CONTINUES TO BE THE SLOWEST IN BREAKING DOWN THIS WARM LAYER
/RESULTING IN THE LEAST AMOUNT OF SNOW/...WHILE THE GFS/NAM ARE
SIMILAR AND CONVERT THINGS TO SNOW CONSIDERABLY FASTER...SETTING UP
THE POTENTIAL FOR SOME SNOWFALL AMOUNTS GREATER THAN A
FOOT...ESPECIALLY IN WRN MN. IN THE GRIDS...TRIED BLENDING BETWEEN
THE ECMWF AND NCEP MODELS AS MUCH AS POSSIBLE...BUT CERTAINLY THINK
MORE REFINEMENTS WILL BE NEEDED GOING FORWARD.
AS FOR HEADLINES...UPGRADED PART OF THE WATCH TO A WARNING...
INCLUDING THE TWIN CITIES METRO...GIVEN THE POTENTIAL FOR THE
PL/FZRA MIX TONIGHT...FOLLOWED BY THE POTENTIAL FOR 6-8+ INCHES OF
SNOW TUESDAY NIGHT THROUGH WEDNESDAY NIGHT. CONVERTED NRN TIER OF
COUNTIES TO AN ADVY SINCE THERE ARE QUESTIONS AS TO JUST HOW MUCH
PRECIPITATION REACHES THAT FAR NORTH. ALSO ADDED A COUPLE ROWS OF
BUFFER COUNTIES TO THE ADVY SOUTH OF THE WARNING...WITH MORE RAIN
ISSUES EXPECTED HERE. ALSO EXTENDED THAT ADVY ACROSS THE WI
COUNTIES...MAINLY FOR THE PL/FZRA THREAT TONIGHT. WITH THE SLOWNESS
OF THE ECMWF WITH BREAKING DOWN THE WARM NOSE ACROSS ERN AREAS...DID
NOT FEEL CONFIDENT WITH EXTENDING A WARNING INTO WI...THOUGH IF IT
IS LOOKING LIKE THE NAM/GFS SOLN WILL WIN OUT...THEN THE WI ADVY
COULD EASILY BE UPGRADED TO A WARNING.
.LONG TERM...(WEDNESDAY THROUGH TUESDAY)
BY WEDNESDAY MORNING...VERY DEEP 50H LONG WAVE TROUGH DIGGING DEEP
INTO THE CENTRAL PORTION OF OLD MEXICO. MID LEVEL LOW PRESSURE
FORMS OVER NE AND CENTRAL SODAK. BY WED/18Z MID LEVEL LOW
DEEPENS...WHILE SURFACE CYCLONE CONTINUES TO EJECT OUT FROM UNDER
THE 50H TROF INTO CENTRAL MO. LAST SLIVER OF -RA/-FZRA/IP OVER FAR
SE CWA FINALLY TRANSITIONS TO ALL SNOW BY LATE MORNING ON WED. USED
BUFKIT SOUNDING FOR TIMING OF SAME. REMAINDER OF PCPN ASSOCIATED
WITH STORM SYSTEM WILL BE SNOW. NAM CONTINUES TO GENERATE THE
HEALTHIEST AMOUNT OF QPF...WHEREAS EUROPEAN IS TRENDING TOWARD
THE LOWER END OF THE SPECTRUM. HAVE GRAVITATED TOWARD THE MIDDLE
GROUND...WITH A COMBO MOISTURE CONTENT SOMEWHERE BETWEEN THE GFS40
AND EUROPEAN. BEST 600MB DENDRITIC GROWTH VALUES BEGIN TO KICK
IN ACROSS WEST CENTRAL MN BY WEDNESDAY MORNING...AND REMAIN OVER
THIS REGION FOR BULK OF THE EVENT...FINALLY REACHING SOUTH CENTRAL
AND EAST CENTRAL MN BY EARLY THU AFTN.
WITH THAT SAID TOTAL FORECASTED SNOWFALL FOR THE EVENT RANGES FROM
ABOUT 5 INCHES NORTH OF A LINE FROM ALEXANDRIA TO RICE LAKE WI. MUCH
OF THE REMAINDER OF THE CWA WILL INCUR BETWEEN 6 AND 10 INCHES OF
SNOW...WITH HEAVIEST AMOUNTS ANTICIPATED OVER SWIFT
...CHIPPEWA...LAC QUI PARLE AND YELLOW MEDICINE COUNTIES. OF COURSE
WITH BANDING EFFECTS SCATTERED SNOWFALL AMOUNTS NEAR 8 INCHES SHOULD
ALSO BE EXPECTED OVER PORTIONS OF WEST CENTRAL WISCONSIN. ALTHOUGH
HEAVY WATER CONTENT SNOWFALL WILL OCCUR ...MODERATE NORTHEASTERLY
FLOW WED AFTN INTO EARLY WED EVE COULD GENERATE SOME OCNL LOW END
DRIFTING. CLOSED 50H LOW WILL FINALLY EXIT WESTERN WI ON FRIDAY
MORNING. MAINLY FLURRY OR SNOW SHOWER ACTIVITY EXPECTED TO ITS
IMMEDIATE LEE ON FRIDAY MORNING.
ZONAL FLOW KICKS IN ACROSS MUCH OF NORTHERN US ON FRIDAY NIGHT
AND CONTINUES INTO THE WEEKEND. THIS WILL UNDOUBTEDLY ALMOST
GUARANTEE AT LEAST MOSTLY CLOUDY CONDITIONS ACROSS THE REGION
INTO MONDAY. ZONAL FLOW WILL ALSO USHER IN A NEW HYBRID EARLY
SPRING STORM SYSTEM BY SATURDAY NIGHT. FORTUNATELY FOR FLOODING
CONCERNS THIS SYSTEM WILL NOT PRODUCE AS MUCH MOISTURE NOR
LAST AS LONG AS THE MID WEEK SYSTEM. IT ALSO APPEARS AT THIS
JUNCTURE THAT ENOUGH WARM AIR WILL BE IN PLACE TO GENERATE
MORE OF A RAIN/SNOW OR RAIN EVENT AS BULK OF STORM SYSTEM
VACATES REGION BY MONDAY MORNING. AFTER THAT ANOTHER LONG
WAVE TROUGH WILL DIG ACROSS THE PACIFIC NORTHWEST INTO NEXT
WEDNESDAY. TEMPERATURES WILL REMAIN ROUGHLY 10 DEGREES BELOW
NORMAL THROUGH MUCH OF THE NEXT 7 DAYS.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1159 PM CDT MON APR 8 2013
TRICKY FORECAST WITH RESPECT TO PRECIPITATION TYPES...BUT
CONFIDENCE IS HIGH IN A PROLONGED PERIOD OF LOW-END MVFR TO IFR
CONDITIONS ACROSS ALL TAF SITES LATE TONIGHT THROUGH WEDNESDAY
MORNING...AND EVEN BEYOND. SLOW LUMBERING LOW PRESSURE SYSTEM
COMING OUT OF THE FOUR CORNERS REGION WILL SPREAD A LARGE SWATH OF
MOISTURE ACROSS THE REGION OVERNIGHT. PRECIPITATION WILL COME
MOSTLY IN THE FORM OF RAIN FOR EASTERN-SOUTHERN MN INTO WESTERN
WI...BUT WESTERN MN WILL SEE A MIX OF WINTRY PRECIP TYPES THROUGH
THE DAY TDA. KAXN HAS A BEST SHOT AT PROLONGED PERIODS OF -SN
WHILE KSTC WILL SEE THE MOST MIXED PRECIP IN THIS TAF CYCLE. THE
REMAINING TAF SITES WILL REMAIN PRIMARILY AS RAIN...LGT TO MOD
INTENSITY. MORE OF A RAPL/RASN MIXTURE WILL DEVELOP LATE TUES EVE
THRU WED MRNG. HAVE KEPT CIGS FAIRLY LOW...MOSTLY IN THE IFR
RANGE...WHILE VSBY ARE NOT EXPECTED TO BE LOWER THAN 2SM...THOUGH
WHERE -SN OCCURS VSBY CAN EASILY BE LOWER. WINDS WILL REMAIN
STRONG OUT OF THE NE...WHICH MAY CAUSE ADDITIONAL VSBY ISSUES IF
-SN IS THE PREDOMINANT PRECIP TYPE.
KMSP...CIGS HAVE RISEN TO OVC024 SO HAVE INITIALIZED AS SUCH IN
THE 09/06Z TAF. HOWEVER...AS ADDITIONAL LOW LEVEL MOISTURE IS
ADVECTED INTO THE REGION IN ADVANCE OF THE LARGE LOW PRES
SYSTEM...CIGS ARE EXPECTED TO LOWER UNDER THE 1700 FT THRESHOLD
OVERNIGHT AND REMAIN THERE THROUGH THE MORNING PUSH. PRECIP LOOKS
TO MOVE IN ARND DAYBREAK...BUT IS EXPECTED TO BE ALL LIQUID.
PERIODS OF MOD RAIN ARE EXPECTED MID-LATE MRNG...THEN TAPER OFF
LATE IN THE DAY. AS COLDER AIR WORKS INTO THE REGION...A WINTRY
MIX OF PRECIP IS EXPECTED LATE TNGT THRU WED MRNG WITH CEILINGS
BOUNCING BETWEEN LOW-END MVFR AND IFR RANGES. WINDS TO REMAIN FROM
030-050 IN THE 15G25KT AREA.
/OUTLOOK FOR KMSP/
WED...IFR CIGS/MVFR VSBYS WITH SN BR. NE WIND 15G25 KTS.
THU...MVFR OR LOWER CIGS/VIS WITH SN. NE WIND 20G30 KTS.
FRI...VFR OR BECOMING VFR IN THE MORNING NW WIND 5 TO 10 KTS.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER WEATHER ADVISORY FROM 7 PM THIS EVENING TO 1 PM CDT
THURSDAY FOR MNZ041>045-050-074>077-082>085.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR MNZ047>049-
054>058-064-065-073.
WINTER STORM WARNING FROM 7 PM THIS EVENING TO 1 PM CDT THURSDAY
FOR MNZ051>053-059>063-066>070.
WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR MNZ078.
WI...WINTER WEATHER ADVISORY FROM 1 AM WEDNESDAY TO 7 PM CDT THURSDAY
FOR WIZ014>016-023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...JC
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
959 PM CDT WED APR 10 2013
.DISCUSSION...THE COLD FRONT NOW EXTENDS FROM NEAR MONTICELLO AR TO
JUST WEST OF MONROE LA TO WEST OF ALEXANDRIA LA. A LINE OF STORMS
CONTINUE TO TRACK ALONG THE FRONT FROM EASTERN AR NORTHWARD INTO THE
MO BOOTHEEL. HOWEVER THE VAST MAJORITY OF ACTIVITY FROM THE GULF
COAST NORTHWARD INTO ARKANSAS IS ELEVATED POST-FRONTAL CONVECTION.
AS HIGHLIGHTED IN THE LATEST SPC MD...THE PRIMARY TORNADO THREAT IN
THE ONGOING WATCH WILL BE WITH THE LINE OF STORMS POTENTIALLY ROOTED
AT THE SURFACE MOVING FROM SE ARKANSAS INTO NW MISSISSIPPI...WHERE
MESOANALYSIS INDICATED 0-3 KM SRH OF 250-300 M2/S2 AND MLCAPES
AROUND 1000 J/KG. FARTHER SOUTH WHILE THE TORNADO THREAT IS LESS...
THERE REMAINS A THREAT FOR SEVERE CONVECTION THANKS TO MID-LEVEL
LAPSE RATES OF 6.5-7 C/KM AND INCREASING 0-6 KM BULK SHEAR
MAGNITUDES IN THE 40-50 KT RANGE.
HIGH-RES MODEL GUIDANCE CONTINUES TO INDICATE A VERY SLOW EASTWARD
PROGRESSION OF THE FRONT OVERNIGHT...WITH THE ARW...LOCAL WRF...NAM
AND HRRR ALL SUGGESTING IT MAY NOT REACH THE JACKSON METRO UNTIL
AROUND 12Z. SOME OF THE SAME HIGH-RES MODEL GUIDANCE SUGGESTS THERE
THE POTENTIAL FOR LOCALIZED RAINFALL AMOUNTS OF 4-6 INCHES OVER THE
WESTERN HALF OF THE CWA. THIS ONLY SERVES TO REINFORCE FLASH FLOOD
CONCERNS...AND THE FLASH FLOOD WATCH CONTINUES FOR MOST OF THE CWA
THROUGH TOMORROW AFTERNOON.
ALL IN ALL...THE GOING FORECAST HAS A PRETTY GOOD HANDLE ON THE
CURRENT SITUATION...BUT WE WILL BE MAKING PERIODIC UPDATES TO HOURLY
TEMP/DEWPOINT/WIND GRIDS TO KEEP TRACK OF THE FRONT. UPDATED
PRODUCTS ARE CURRENTLY BEING SENT. /DL/
&&
.AVIATION...VFR CONDITIONS ONGOING THIS EVENING BUT AS RAIN AND
STORMS MOVE IN FROM THE WEST SLOWLY OVERNIGHT...MVFR TO LOCALLY IFR
CEILINGS WILL RETURN TO TAF SITES MOSTLY ALONG AND WEST OF THE I-55
CORRIDOR THROUGH 12Z. TAF SITES EAST OF I-55 WILL BE IMPACTED FROM
12-19Z THURSDAY WITH RAIN TAPERING OFF BY 23Z. BEHIND RAIN AND
FROPA...WINDS WILL SHIFT OUT OF THE WEST THEN NORTH/NORTHWEST AROUND
10-15KTS THURSDAY. SKIES WILL CLEAR THROUGH THE DAY AND VFR
CONDITIONS SHOULD RETURN FROM WEST TO EAST. /28/
&&
.PREV DISCUSSION... /ISSUED AT 503 PM CDT WED APR 10 2013/
THE PRIMARY SHORTWAVE TROUGH WILL SWING ACROSS THE AREA BY THURSDAY
AFTERNOON AND THIS COULD SUPPORT RE-INTENSIFICATION OF THE SEVERE
WEATHER POTENTIAL OVER EASTERN MISSISSIPPI...ALTHOUGH IT APPEARS THE
GREATER RISK WILL SET UP OVER ALABAMA WHERE GREATER DAYTIME HEATING
AND DESTABILIZATION WILL OCCUR. EXPECT THIS WAVE TO FORCE THE
CONVECTIVE SYSTEM EASTWARD AT A MORE RAPID PACE AND CONVECTION WILL
END BY THURSDAY EVENING WITH DRIER AND COOLER CONDITIONS EXPECTED
THURSDAY NIGHT. /EC/
FRIDAY THROUGH WEDNESDAY...DRY FRIDAY WITH TEMPERATURES TOPPING OUT
JUST BELOW NORMAL IN THE LOWER 70S. NORMAL HIGHS RUN IN THE MID 70S.
THE 00Z MAV GUIDANCE AND GFS ENSEMBLE MEANS CAME IN SEVERAL DEGREES
WARMER THAN LAST NIGHT`S RUN AND LOOK REASONABLE. THE CLOSED UPPER
LOW WILL BE OVER THE GREAT LAKES REGION WITH NEAR ZONAL FLOW ALOFT
OVER OUR REGION. AT THE SURFACE...HIGH PRESSURE WILL BE RIDGING
SOUTHEAST FROM THE PLAINS ACROSS OUR CWA. NEAR FULL INSOLATION...WITH
ONLY A LIGHT NORTH WIND WITH LOW RELATIVE HUMIDITY SHOULD ALLOW
TEMPERATURES TO WARM RAPIDLY FRIDAY MORNING. OUR FLOW ALOFT WILL BACK
TO THE SOUTHWEST FRIDAY NIGHT INTO SATURDAY AHEAD OF A TROUGH OVER
THE DESERT SOUTHWEST. THE GFS AND ECMWF DIFFER WITH THIS FEATURE AS
THE GFS HAS A CLOSED LOW OVER THE BAJA REGION BY SATURDAY MORNING
WHILE THE ECMWF HAS AN OPEN TROUGH. THE ECMWF IS FASTER IN SWINGING
THE TROUGH EAST TO THE SOUTHERN PLAINS BY SUNDAY MORNING WHILE THE
GFS HOLDS THE CLOSED LOW BACK OVER OLD MEXICO. AS THE SURFACE RIDGE
SHIFTS EAST OF OUR AREA SATURDAY NIGHT RETURN FLOW WILL BEGIN
INCREASING MOISTURE TO THE REGION SUNDAY. THIS SHOULD LEAD TO RAIN
DEVELOPING OVER THE SOUTHERN ZONES SUNDAY AFTERNOON. THE ECMWF IS
MORE GENEROUS WITH THE RAIN DUE TO THE CLOSER PROXIMITY OF THE
APPROACHING SHORTWAVE TROUGH BUT THE GFS CATCHES UP SUNDAY NIGHT. BY
MONDAY MORNING THE ECMWF HAS THE AXIS OF THE SHORTWAVE EAST OF OUR
CWA WHILE THE GFS PLACES THE AXIS OVER THE ARKLATEX. BOTH MODELS
MAINTAIN A SOUTHWEST FLOW ALOFT ACROSS OUR REGION WITH SEVERAL
ADDITIONAL EMBEDDED DISTURBANCES THROUGH WEDNESDAY THAT WILL COMBINE
WITH DAYTIME HEATING AND INCREASING MOISTURE TO PROVIDE AT LEAST
DIURNALLY DRIVEN CHANCES OF SHOWERS AND THUNDERSTORMS. BOTH MODELS
ARE SHOWING A SURGE OF UPPER 60 TO LOWER 70 DEW POINTS INTO THE
SOUTHERN PORTIONS OF OUR CWA MONDAY THROUGH WEDNESDAY TO HELP FUEL
THE CONVECTION. WARMER THAN NORMAL TEMPERATURES ARE ALSO EXPECTED
SUNDAY THROUGH WEDNESDAY. HOWEVER...MODEL DIFFERENCES ARE FURTHER
AMPLIFIED BY WEDNESDAY MORNING AS THE GFS HAS A CLOSED LOW TRACKING
ACROSS THE NORTHERN PLAINS WITH NEAR ZONAL ACROSS MUCH OF THE WESTERN
CONUS. THE ECMWF HAS AN AMPLIFIED TROUGH OVER THE ROCKIES. EITHER
SCENARIO WILL STILL LEAD TO DISTURBED WEATHER OVER OUR REGION THROUGH
MID WEEK. /22/
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR MSZ018-019-025>030-032>038-040>045-047>050-
053>055-059>063.
LA...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR LAZ007>009-015-016-023>026.
AR...FLASH FLOOD WATCH FROM 7 PM CDT THIS EVENING THROUGH THURSDAY
AFTERNOON FOR ARZ074-075.
&&
$$
DL/28/EC/22
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
902 PM CDT Wed Apr 10 2013
.UPDATE...
Issued at 900 PM CDT WED APR 10 2013
Widespread rains have shifted east of the CWA this evening, therefore
have cancelled flood watch. Weak shortwave energy rotating around the
trough will continue to produce a band of showers and moderate
drizzle as it pivots into the region. HRRR guidance seems to capture
ongoing trends well, with this band of showers pivoting into northern
Missouri and eventually Iowa by Midnight.
Otherwise remaining forecast remains on track as temperatures slowly
cool through the 30s overnight.
&&
.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 00Z TAFS through 00Z Thursday Evening)
Issued at 612 PM CDT WED APR 10 2013
There may be a brief improvement in ceilings directly behind the
departing rain, however radar already showing areas of drizzle or
light sprinkles reforming early this evening. Generally IFR ceilings
will continue through the evening, before an increased potential for
LIFR ceilings towards and after midnight. Visibility will be highly
variable through the night, but generally expect major aviation
points to remain near 3SM through the night, with very brief
reductions below this level.
Additional moisture rotating around the upper level storm system will
keep ceilings at least in the MVFR category into the afternoon before
improvement late in the day.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Dux
SHORT TERM...MJ
LONG TERM...Blair
AVIATION...Dux
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
615 PM CDT Wed Apr 10 2013
...UPDATED FOR AVIATION...
.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 00Z TAFS through 00Z Thursday Evening)
Issued at 612 PM CDT WED APR 10 2013
There may be a brief improvement in ceilings directly behind the
departing rain, however radar already showing areas of drizzle or
light sprinkles reforming early this evening. Generally IFR ceilings
will continue through the evening, before an increased potential for
LIFR ceilings towards and after midnight. Visibility will be highly
variable through the night, but generally expect major aviation
points to remain near 3SM through the night, with very brief
reductions below this level.
Additional moisture rotating around the upper level storm system will
keep ceilings at least in the MVFR category into the afternoon before
improvement late in the day.
&&
.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...Dux
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1201 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 935 PM CDT MON APR 8 2013
00Z SOUNDINGS INDICATE VERY WARM MID LEVEL TEMPS SURGED INTO
MISSOURI LATE THIS AFTERNOON AND EARLY THIS EVENING...WITH LATEST
ACARS SOUNDINGS SUGGESTING THIS WARMING HAS REACHED AS FAR E AS
STL AREA. THIS DATA...COMBINED WITH LATEST SHORT-RANGE GUIDANCE...WOULD
CERTAINLY SUGGEST THAT EML WILL BE CAPPING ANY CONVECTION TRYING
TO FORM AOB 700 MB ALONG AND SOUTH OF AN MBY-STL-SLO LINE. IN N/NE
PARTS OF OUR CWA MESOANALYSIS IS INDICATING SOME WEAK LOW LEVEL
CONVERGENCE...AND SINCE CAPPING ISN`T AS INTENSE HAVE CONTINUED
SOME LOW POPS HERE UNTIL THE PREDAWN HOURS...WHEN FORCING/LIFT
TIED TO INCREASE OF LOW LEVEL JET WILL COMMENCE. HOWEVER...EVEN
THEN THE BEST FORCING WITH THIS FEATURE WILL BE FURTHER N ACROSS
IOWA/N IL...SO HAVE ADJUSTED PRECIP THREAT A BIT TO CONFINE
LIKELY POPS TO AREAS N OF UIN.
FORECAST IS PROCESSING AND WILL BE OUT IN A SECOND.
TRUETT
&&
.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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 1137 PM CDT MON APR 8 2013
STILL THINKING THAT THERE COULD BE A FEW STORMS LATER TONIGHT OVER
NORTHEAST MISSOURI AND WEST CENTRAL ILLINOIS...THOUGH
PROBABILITIES ARE LOOKING LOWER AND LOWER AS THE NIGHT CONTINUES.
ALSO...VFR CIGS CONTINUE TO CLEAR FROM SOUTH TO NORTH THROUGH THE
MISSISSIPPI VALLEY. THINK VFR CONDITIONS WILL PREVAIL ALONG AND
EAST OF THE MISSISSIPPI...AND THE 4000-5000FT DECK MAY CLEAR OUT
ENTIRELY. STILL COULD SEE SOME HIGH MVFR CIGS IN CENTRAL AND
NORTHEAST MISSOURI/WEST CENTRAL ILLINOIS...ESPECIALLY IF IT RAINS
UP NORTH. ANY MVFR CIGS THAT DO FORM SHOULD SCATTER AND LIFT
TUESDAY AS DAYTIME HEATING MIXES THE LOWER ATMOSPHERE. WIND WILL
BECOME SOUTHERLY AND GUSTY BY LATE MORNING/EARLY AFTERNOON WITH
VFR FLIGHT CONDITIONS CONTINUING. NEXT CHANCE FOR PRECIP WILL MOST
LIKELY BE LATE TUESDAY EVENING.
SPECIFICS FOR KSTL...
EXPECT VFR FLIGHT CONDITIONS TO PREVAIL FOR THE REST OF THE NIGHT
AT LAMBERT. 4000-5000FT CIGS LOOK LIKE THEY MAY EVEN CLEAR FROM
THE SOUTH LATER TONIGHT...BUT AM NOT THAT CONFIDENT THAT THE LOW
LEVEL JET WON`T CONTINUE TO KEEP MOISTURE AND CLOUDS GOING.
SOUTHEAST WIND WILL BECOME SOUTHERLY BY MID-MORNING AND GUSTS TO
AROUND 25KTS LOOK LIKELY. NEXT CHANCE FOR PRECIP LOOKS LIKE IT
COULD BE AS EARLY AS MID-LATE TUESDAY EVENING.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
348 PM MDT TUE APR 9 2013
.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 OBSERVATIONAL 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...
SNOW SEEMS TO HAVE WINDED DOWN AT ALL TERMINALS...WHICH IN TURN IS
RAISING CEILINGS AND INCREASING VISIBILITIES. EXPECTING CONDITIONS
TO GET BETTER THROUGH THE EVENING HOURS AND INTO TOMORROW. THERE
IS A CHANCE FOR A LINGERING SNOW SHOWER...ESPECIALLY NEAR THE
MOUNTAINS. VFR CONDITIONS SHOULD PREVAIL ON WEDNESDAY AS THE STORM
SYSTEM EXITS TO THE EAST. SINGER
&&
.PRELIMINARY POINT TEMP/POPS...
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 012/044 032/054 032/052 035/053 030/048 026/046 027/048
01/U 53/W 22/W 34/W 33/W 33/W 33/W
LVM 013/053 031/055 026/053 032/051 023/044 020/044 020/045
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
11/B 55/W 22/W 34/W 33/W 33/W 23/W
MLS 014/040 025/049 029/049 032/052 032/047 028/043 026/047
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
31/B 25/W 23/W 23/W 43/W 33/W 34/W
BHK 017/036 020/041 026/045 026/047 030/041 025/041 024/042
11/B 14/W 23/W 14/W 43/W 33/W 22/W
SHR 011/040 024/049 027/050 029/052 027/044 024/043 024/045
41/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
1137 AM MDT TUE APR 9 2013
.SHORT TERM...VALID FOR TDY AND WED...
THE WINTER STORM WARNING FOR THE BEARTOOTH AND RED LODGE FOOTHILLS
WILL BE ALLOWED TO EXPIRE AS PLANNED AT NOON. THERE ARE STILL WEAK
RADAR RETURNS IN THOSE AREAS...AND WEAK UPSLOPE FLOW WILL PROBABLY
KEEP SOME LIGHT SNOW GOING ALONG PART OF THE FOOTHILLS FOR A WHILE
THIS AFTERNOON LIKE THE 12 UTC NAM AND 16 UTC RAP SHOW. HOWEVER...
THE SUN IS ACTUALLY TRYING TO PEAK THROUGH NEAR NYE PER RECENT WEB
WEB CAMERA IMAGES...SO LOW-LEVEL DRYING IS BEGINNING. THE HEADLINE
CAN THUS BE DROPPED IN THOSE AREAS. SCHULTZ
PREVIOUS DISCUSSION...ISSUED AT 935 AM MDT TUE 9 APR 2013...
WE UPDATED THE FORECAST TO DROP POPS OUT OF THE FORECAST TODAY FOR
THE CITY OF BILLINGS...AND INSTEAD WENT WITH THE IDEA OF FLURRIES.
RADAR IMAGERY HAS SHOWN A HALT TO THE NORTHWARD ADVANCE OF SNOW IN
FAR SOUTHERN MT OVER THE LAST ONE TO TWO HOURS THANKS TO LOW-LEVEL
DRYING. WE ALSO ADDED FLURRIES ALONG THE REST OF THE NORTH SIDE OF
THE MORE ESTABLISHED SNOW AS WELL...FROM LIVINGSTON ALL THE WAY TO
AROUND BAKER. LIVINGSTON HAS HAD MORE LEGITIMATE LIGHT SNOW WITH A
VISIBILITY UNDER 3 MILES AT TIMES THANKS TO UPSLOPE ENHANCEMENT IN
THAT AREA...BUT AS OF 15 UTC THAT HAS TRANSITIONED TOWARD A FLURRY
MODE TOO...SO WE DECIDED TO GO THAT ROUTE INSTEAD OF ADDING LIKELY
OR CATEGORICAL POPS LIKE WE HAD BEEN CONSIDERING.
OTHERWISE...THE REST OF THE FORECAST APPEARS ON TRACK. WEB CAMERAS
SHOW SNOW CONTINUING IN THE BEARTOOTH AND RED LODGE FOOTHILLS...SO
WE WILL LEAVE THE WARNING FOR THOSE AREAS IN EFFECT UNTIL NOON. WE
WILL PROBABLY BE ABLE TO LET IT GO AT THAT POINT THOUGH AS IMPACTS
SHOULD BE WANING EVEN IF SOME LIGHT SNOW CONTINUES BEYOND THEN. WE
WILL ALSO LEAVE THE WINTER STORM WARNINGS OVER SHERIDAN COUNTY AND
THE THE NORTHEAST BIG HORN MOUNTAINS UP INTO FAR SOUTHERN MT UP AS
SNOW CONTINUES THERE AS WELL. WE DID SOME SMALL FINE-TUNING TO THE
POPS AND SNOW AMOUNTS FOR THOSE AREAS...THOUGH WE COULD NEED TO DO
A BIT MORE TOWARD MIDDAY. IN GENERAL...ANOTHER 2 TO 4 INCHES LOOKS
FEASIBLE IN THOSE AREAS TODAY. FINALLY...WE LARGELY LEFT HIGHS FOR
TODAY ALONE...BUT THE TWO NEW SETS OF GUIDANCE WE HAVE SO FAR THIS
MORNING DISAGREE ON WHETHER SUBTLE CHANGES MIGHT BE NEEDED. THE 12
UTC NAM SAYS WE MIGHT BE A BIT TOO WARM IN PLACES...WHILE THE LAST
FEW LAMP GUIDANCE CYCLES SUGGEST WE MAY BE A BIT TOO COOL FOR SOME
SPOTS. THE GOING FORECAST IS A GOOD COMPROMISE AND IS CLOSE TO THE
06 UTC MULTI-MODEL CONSENSUS. SCHULTZ
.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...
DETAILS IN THE EXTENDED FORECAST WILL SUBJECT TO SHIFTS IN TIMING AND
STRENGTH OF DISTURBANCES MOVING THROUGH THE REGION BUT THE OVERALL
PATTERN IS EASY TO DEPICT. WAVE APPROACHES MONTANA ON THURSDAY AND
DEEPENS A BIT THURSDAY NIGHT WITH A PACIFIC FRONT THURSDAY NIGHT.
UNSETTLED NORTHWEST FLOW CONTINUES UNTIL SATURDAY WHEN A DEEPER
SYSTEM BEGINS MOVING INTO THE PACIFIC NORTHWEST INDUCING HEIGHT
FALLS OVER MONTANA AND WYOMING. THIS SYSTEM WILL DEEPEN AND MOVE
INTO WESTERN MONTANA SATURDAY NIGHT. FOR SUNDAY AND BEYOND THE JET
STREAM WILL REMAIN WELL SOUTH OF THE REGION SUPPORTING BELOW
NORMAL TEMPERATURES AND SCATTERED SHOWER ACTIVITY.
THE THURSDAY SYSTEM COULD HAVE SOME DECENT SHOWER ACTIVITY
ASSOCIATED WITH IT BECAUSE THERE IS A DECENT TAP INTO THE PACIFIC
FOR MOISTURE SO WILL HAVE TO WATCH TO SEE HOW QUICKLY THE HEIGHT
FALLS OCCUR AND THE TIMING OF THE FRONT.
AT THIS POINT IN TIME THE TRACK OF THE WEEKEND SYSTEM APPEARS TO
BE FAR ENOUGH NORTH THAT SOUTHERN MONTANA AND NORTHERN WYOMING
WILL NOT SEE SIGNIFICANT IMPACTS. BEST PRECIPITATION SHOULD WRAP
INTO THE NORTH SIDE OF THE LOW WITH PERIODS OF DRY SLOTTING
LIKELY ACROSS SOUTHERN MONTANA. BORSUM
&&
.AVIATION...
MAJOR STORM SYSTEM OVER WYOMING AND COLORADO SPREADING SNOW AND
LOW CLOUDS INTO THE SOUTHERN PORTION OF THE FORECAST AREA. UPSLOPE
WINDS KEEPING A THREAT OF MVFR CEILINGS AT MOST OF THE TAF SITES
TODAY. SNOW HAS ENDED FOR MOST SITES EXCEPT KSHR WHERE IT WILL
CONTINUE FOR MOST OF THE DAY. IFR CEILINGS ARE POSSIBLE SOUTH OF A
KBIL-KMLS WITH MOUNTAIN OBSCURATIONS CONTINUING. BORSUM/SCHULTZ
&&
.PRELIMINARY POINT TEMP/POPS...
TDY WED THU FRI SAT SUN MON
-------------------------------------------------------
BIL 032 017/044 032/054 032/053 031/055 032/053 029/052
1/M 01/U 44/W 22/W 34/W 33/W 33/W
LVM 035 016/051 033/056 030/053 030/053 027/050 025/048
1/M 01/B 42/W 22/W 34/W 33/W 33/W
HDN 029 015/043 027/053 028/053 026/056 029/054 026/052
6/J 11/B 34/W 22/W 34/W 33/W 33/W
MLS 029 016/040 026/048 028/051 026/052 029/050 027/045
1/E 11/U 24/W 23/W 25/W 43/W 23/W
4BQ 024 013/036 021/044 024/049 024/053 027/052 024/049
9/S 31/B 13/W 22/W 23/W 43/W 22/W
BHK 025 014/036 020/041 024/046 024/047 024/044 022/042
1/C 11/B 13/W 23/W 14/W 43/W 22/W
SHR 025 012/040 024/049 027/049 025/053 027/050 025/049
+/S 21/B 23/W 33/W 23/W 43/W 44/W
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR ZONES 36>38-58.
WY...WINTER STORM WARNING IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR ZONES 98-99.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
417 AM CDT TUE APR 9 2013
.DISCUSSION...
VERY ACTIVE WEATHER WILL CONTINUE OVER THE NEXT 24-36 HOURS WITH
NUMEROUS WEATHER ELEMENTS IN OUR FORECAST.
CONVECTION IS UNDERWAY ACROSS THE REGION ALONG A SLOWLY SOUTHWARD
SAGGING BOUNDARY EXTENDING FROM SURFACE LOW PRESSURE CENTERED OVER
NORTHEAST NEW MEXICO THROUGH NORTHWEST KANSAS...INTO EAST CENTRAL
NEBRASKA AND ACROSS CENTRAL IOWA. FOR THE MOST PART...CONVECTION HAS
REMAINED ALONG AND NORTH OF THE BOUNDARY BUT SOME SCATTERED ACTIVITY
HAS BEEN ABLE TO DEVELOP IN THE WARM SECTOR ACROSS SOUTH CENTRAL
NEBRASKA. 850MB MOISTURE IS PLENTIFUL WITH 45-50KT SOUTHERLY LOW
LEVEL JET TRANSPORTING NEARLY +12C DEWPOINTS INTO THE SOUTHERN CWA.
SHORT RANGE MODEL INDICATIONS ARE FOR A CONTINUATION OF EASTWARD
PROPAGATION ALONG THE BOUNDARY WITH SOME TRAINING OF STORMS
POSSIBLE. PW`S REMAIN AROUND 1". A FEW OF THE NEAR TERM CONVECTIVE
MODELS...INCLUDING THE 01Z HRRR...INDICATE A TRANSITION FROM
SCATTERED CELLS TO A BOWING SEGMENT OF SORTS PUSHING INTO EASTERN
NEBRSAKA OVER THE NEXT COUPLE HOURS. THIS WILL WILL NEED TO BE
WATCHED CLOSELY EARLY THIS MORNING. ANY STORMS THAT DO REACH SEVERE
LIMITS WOULD BE CAPABLE OF PRODUCING DAMAGING WIND AND MAYBE SOME
LARGE HAIL...BUT MAINLY HEAVY RAIN.
SHORTWAVE MID LEVEL RIDGING WILL PUSH NORTHEAST ACROSS THE CWA TODAY
AS THE SURFACE BOUNDARY PUSHES A BIT FURTHER EAST WHILE THE SFC LOW
MOVES INTO THE TEXAS PANHANDLE. WIDESPREAD PRECIPITATION IS
POSSIBLE OVER MUCH OF CENTRAL AND NORTHEAST NEBRASKA THROUGHOUT THE
DAY ON THE COLD SIDE OF THE SURFACE BOUNDARY. CONVECTION IS EXPECTED
TO REDEVELOP IN THE WARM SECTOR AS INSTABILITY INCREASES AND REGION
IS IN A SLIGHT RISK FOR THE DAY ONE OUTLOOK. MEANWHILE...OUR FAR
NORTHWESTERN COUNTIES WILL BE UNDER THE GUN FOR A FREEZING
RAIN/SLEET SCENARIO AS A WARM NOSE OF 850MB AIR WRAPS NORTHWEST
INTO THE SYSTEM WHILE THE COLD AIR UNDERCUTS THIS AT THE SURFACE.
THERE APPEARS TO BE ABOUT A 24 HOUR PERIOD OF THE POTENTIAL FOR
FREEZING RAIN AND/OR SLEET ACROSS A FEW COUNTIES IN OUR
NORTHWEST...WITH THE POTENTIAL FOR ACCUMULATING SNOW OF AROUND
2-4". AS A RESULT...HAVE UPGRADED THE WATCH TO A WARNING FOR
ANTELOPE AND KNOX COUNTIES AND CONVERTED THE WATCH TO AN ADVISORY
FOR THE NEXT TIER OF COUNTIES SOUTHEAST OF KNOX AND ANTELOPE.
USING THE TOP DOWN METHOD WOULD GIVE US A 24 HOUR PERIOD OF
FREEZING RAIN/SLEET AT KOFK...WITH UP TO A TENTH OF AN INCH OF ICE
POSSIBLE AND HOPEFULLY NOT MORE. GFS/SREF/NAM ALL SHOW THIS. THE
SREF ALSO PAINTS A 50% PROBABILITY OF MEASURABLE FZRA STRIPE
ACROSS A GOOD PORTION OF NORTHEAST NEBRASKA. THE NOSE OF WARM AIR
AROUND 850MB WILL SLOWLY COOL BELOW FREEZING FROM NORTHWEST TO
SOUTHEAST ACROSS THE CWA TURNING THIS MIX OVER TO SNOW BY MID DAY
WEDNESDAY. THIS TIME PERIOD IS QUITE CHALLENGING AS SFC
TEMPERATURES MAY RISE ABOVE FREEZING AND WITH THE STRONG APRIL SUN
ANGLE...IT MAY BE DIFFICULT TO REMAIN COLD ENOUGH FOR WINTERY
PCPN. THERE ARE MANY VARIABLES GOING INTO THIS EVENT AND ANY ONE
THAT VARIES BY A DEGREE OR TWO CAN DRAMATICALLY CHANGE THE
PRECIPITATION TYPE. THE EVOLUTION OF THIS ENTIRE SCENARIO WILL BE
WATCHED CLOSELY AND UPGRADES/DOWNGRADES TO HEADLINES ARE POSSIBLE
AS THIS EVENT UNFOLDS. IN ADDITION TO THE PCPN...NORTH WINDS WILL
BE QUITE BREEZY AND COULD BE AN ISSUE FOR POWERLINES AND TREES IF
THEY ACCUMULATE ANY ICE.
KERN
&&
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK.
PERIODS OF SHOWERS AND THUNDERSTORMS EXPECTED ACROSS THE AREA
THROUGH 10Z WITH LIFR CONDITIONS CONTINUING AT KOFK AND DEVELOPING
AT KOMA AND KLNK THROUGH 12Z. FREEZING RAIN LIKELY AT KOFK AFTER
15Z. LATEST RAP MODEL SHOWS WARM FRONT REMAINING NORTHWEST OF
KOMA AND KLNK THROUGH 18Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER WEATHER ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM CDT
WEDNESDAY FOR NEZ012-017-030-031.
WINTER STORM WARNING FROM 10 AM THIS MORNING TO 1 PM CDT
WEDNESDAY FOR NEZ011-016.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
215 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1051 PM CDT MON APR 8 2013
UPDATED FORECAST FOR EARLIER ONSET OF WINTER WEATHER CONDITIONS
OVER NORTHWEST NEBRASKA. TRANSITION TO SNOW TO THE WEST OF A LINE
FROM CODY TO LISCO.
&&
.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 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 214 AM CDT TUE APR 9 2013
WIDESPREAD SNOW IS EXPECTED TO MOVE INTO NORTHWEST NEBRASKA BY 09Z
AND SLOWLY SPREAD INTO NORTH CENTRAL BY 12Z. IN THE
MEANTIME...SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE SOUTH AND
EAST OF AN ONL-OGA LINE UNTIL AT LEAST 08Z. THEN WIDESPREAD RAIN IN
CENTRAL AND SOUTHWEST NEBRASKA WILL GRADUALLY CHANGE OVER TO SNOW
LATE MORNING AND DURING THE AFTERNOON. THE CHANGE TO SNOW IS LIKELY
AT LBF...OGA AND IML BETWEEN 18Z AND 21Z. IT WILL BE LATE EVENING
BEFORE IT CHANGES TO SNOW IN ONL AND BBW.
WIND IS OF MAJOR CONCERN WITH 350-040 AT 25-34G34-47KT THROUGH AT
LEAST LATE AFTERNOON.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 7 AM CDT /6 AM MDT/ WEDNESDAY FOR
NEZ029-038-058-069>071.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ WEDNESDAY FOR
NEZ006>010-024>028-035>037-056-057-059.
WINTER STORM WARNING UNTIL 7 AM CDT /6 AM MDT/ WEDNESDAY FOR
NEZ004-005-022-023-094.
&&
$$
UPDATE...POWER
SHORT TERM...CDC
LONG TERM...ROBERG
AVIATION...SPRINGER
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1227 AM CDT TUE APR 9 2013
.AVIATION...
06Z TAFS FOR KOMA...KOFK...KLNK.
PERIODS OF SHOWERS AND THUNDERSTORMS EXPECTED ACROSS THE AREA
THROUGH 10Z WITH LIFR CONDITIONS CONTINUING AT KOFK AND DEVELOPING
AT KOMA AND KLNK THROUGH 12Z. FREEZING RAIN LIKELY AT KOFK AFTER
15Z. LATEST RAP MODEL SHOWS WARM FRONT REMAINING NORTHWEST OF
KOMA AND KLNK THROUGH 18Z.
&&
.PREV DISCUSSION... /ISSUED 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
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...WINTER STORM WATCH FROM 10 AM CDT THIS MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ012-017-030-031.
WINTER STORM WATCH FROM 7 AM CDT THIS MORNING THROUGH WEDNESDAY
AFTERNOON FOR NEZ011-016.
IA...NONE.
&&
$$
FOBERT
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1031 PM EDT WED APR 10 2013
.SYNOPSIS...
THERE IS A STALLED FRONTAL BOUNDARY OVER NEW YORK AND PENNSYLVANIA
TODAY. THIS BOUNDARY WILL BE THE FOCUS OF STORMS MOVING EASTWARD
OUT OF THE GREAT LAKES TOWARD OUR AREA. THIS WILL BRING RAIN AND A
CHANCE OF THUNDERSTORMS OVER NORTHEAST PENNSYLVANIA...AND THE
CHANCE OF SOME SPOTTY FREEZING RAIN OVER THE HIGHER ELEVATIONS OF
THE FINGER LAKES IN NEW YORK. DRIER AIR WILL FINALLY MOVE IN
BEHIND A COLD FRONT ON FRIDAY.
&&
.NEAR TERM /THROUGH THURSDAY/...
1020 PM UPDATE...
MAIN AREA OF RAIN NOW WORKING THROUGH THE TWIN TIERS AND MUCH OF
NORTHEASTERN PA AS SUCCESSIVE SHORTWAVE DISTURBANCES TRAVEL EAST
ALONG A STALLED FRONTAL BOUNDARY. LOOKING UPSTREAM...RAIN WILL
LIKELY COME TO AN END FOR A SHORT WHILE BETWEEN 4 AND 6Z...WITH
ADDITIONAL ACTIVITY THEN EXPECTED TO MOVE IN LATER ON AS THE EARLY
MORNING HRS PROGRESS. LATEST LOOK AT AVAILABLE ISENTROPIC FIELDS
SUGGEST NEUTRAL ISENTROPIC UPGLIDE WILL PERSIST THROUGH MUCH OF
THE OVERNIGHT HRS ACROSS CENTRAL AND NORTHERN ZONES...WITH ASCENT
THEN INCREASING ONCE AGAIN AFTER 12Z AS MAIN LOW-LEVEL JET AXIS
APPROACHES FROM THE WEST.
LATEST RUC MLCAPE PLAN VIEW MAPS SHOWING ANY LINGERING INSTABILITY
NOW CONFINED TO AREAS WELL SOUTH OF THE FCST AREA. DESPITE THIS
HOWEVER...SEVERAL INDIVIDUAL STRIKES STILL DETECTED AND THUS WILL
MAINTAIN THUNDER MENTION FOR A FEW MORE HRS ACROSS THE SOUTH. MAIN
CONCERN GOING INTO THU MORNING CONTINUES TO BE PROSPECTS FOR FZRA
AS HIGH PRESSURE SOUTH OF HUDSON BAY CONTINUES TO BUILD SOUTH WITH
TIME EARLY THU MORNING. AS IT STANDS RIGHT NOW...BEST PROSPECTS
WILL BE ACROSS THE CENTRAL FINGER AND NORTHERN SOUTHERN TIER
PORTIONS OF THE FCST AREA HOWEVER CONSIDERING THE AMOUNT OF LOW
STRATUS HANGING AROUND THIS EVENING COUPLED WITH THE FACT THAT
TEMPS WILL LIKELY START WARMING UP FAIRLY QUICKLY TOMORROW
MORNING...FEEL ANY ICING CONCERNS SHOULD BE KEPT TO MINIMUM.
730 PM UPDATE... A FAIRLY BUSY LATE AFTERNOON/EVENING FOR
EARLY APRIL STANDARDS CONTINUES THIS HR WITH THE NEXT MCS
APPROACHING FROM THE WEST. CONVECTION ASSOCIATED WITH THE FIRST
CLUSTER RESULTED IN WIDESPREAD WIND DAMAGE ACROSS THE LOWER
WYOMING VALLEY AND POCONOS WHERE NUMBERS REPORTS OF DOWN TREES
WERE RECEIVED. WITH THIS FEATURE GONE...ATTENTION IS QUICKLY DRAWN
BACK TO OUR WEST WITH LATEST RADAR TRENDS SHOWING AN ORGANIZED
LINE-ECHO WAVE PATTERN (LEWP) STRETCHING FROM JUST NORTH OF
PITTSBURGH NORTHEAST THROUGH CENTRAL PA AND EVENTUALLY THE CENTRAL
CENTRAL TWIN TIERS OF CENTRAL TWIN TIERS. MAIN CULPRIT CONTINUES
TO BE A SERIES OF SHORTWAVE DISTURBANCES TRAVELING ALONG A STALLED
FRONTAL BOUNDARY WHICH REMAINS POSITIONED OVER THE FAR SOUTHERN
PORTION OF THE FCST AREA THIS EVENING. WILL OBVIOUSLY HAVE TO
WATCH POTENTIAL FOR SEVERE THIS EVENING HOWEVER APPROACHING
ACTIVITY IS WORKING INTO A REGION THAT EXPERIENCED THIS
AFTERNOON/S EARLIER CONVECTION. THAT SAID...WE CURRENTLY EXPECT A
WEAKENING TREND WITH FURTHER EASTWARD PROGRESS HOWEVER CANNOT RULE
OUT THE NEED FOR A FEW ROGUE SPS STATEMENTS OR A WARNING OR TWO.
AFTER A FEW HRS...HIGH RES MODELS SHOW A GRADUAL SOUTHWARD SHIFT
TO ONGOING ACTIVITY AS FRONT SLOWLY SAGS SOUTH WITH TIME.
NORTHERLY FLOW WORKING SOUTH FROM NORTHERN NY AND SOUTHERN CANADA
WILL SET THE STAGE FOR COOLING TEMPS TOWARDS MORNING WHERE SOME
LIGHT FZRA WILL BE POSSIBLE ACROSS THE HIGHER ELEVATIONS OF THE
NORTHERN FINGER LAKES...SOUTHERN TUG HILL...AND UPPER SUSQUEHANNA
VALLEY REGIONS. WILL CONTINUE TO MONITOR.
PREVIOUS NEAR TERM DISCUSSION...
COMPLEX SCENARIO OVER THE FCST AREA WITH DFRNT DVLPG WX THREATS.
IN THE VERY NEAR TERM...LINE OF TRWS OVER WRN PA MARCHING EAST
WILL BRING CONV TO THE FCST AREA. ATTM...LOOKS AS THOUGH MORE
LIMITED AVBL CAPE SHD WEAKEN THE CELLS AND THEY MOVE EAST.
HWVR...ANY CELLS WILL NEED TO WATCHED FOR FOR SVR WIND. SPC CRNTLY
NOT XPCTG A WATCH FOR PA.
OTR CNCRN FOR THE OVRNGT IS THE PSBLTY SOME FRZG RAIN LATE. HPC
WWD GRAPHICS PAINT AN AREA OF A TENTH TO QUARTER INCH OF ICE OVER
THE FINGER LAKES. HWVR...HIGH CONFIDENCE TEMPS FCST DUE TO GOOD
AGREEMENT BETWEEN THE MAV AND MET BARELY GENERATES ANY TEMPS AT OR
BLO FRZG UNTIL VERY LATE. CORE OF THE COLD AIR IS OVER THE AREA
AFT SUNRISE TMRW...WHEN MID APRIL SUN WILL MAKE ICE FORMATION DFCLT.
HAVE ELECTED TO HOLD OFF ON ANY FLAGS FOR ICE ATTM DUE TO VERY LOW
CONFIDENCE AND CVRG.
FINAL CNCRN IS QPF AMTS. SOME CONCERN THAT ENUF RAIN COULD FALL TO
CAUSE FLOODING ISSUES. NAM WHICH HAD BEEN FCSTG THE MOST QPF HAS
SLOWLY BACKED OFF. PCPN HAS BEEN ORGANIZING IN CONV COMPLEXES AND
MVG QUICKLY. IT SEEMS AS THROUGH THE THREAT FOR WIDESPREAD FLOOD
ISSUES IS LOW FOR TNGT.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
WV EXITS EARLY THU ALLOWING FOR MID LVL CONV AND A BLDG SFC HIPRES
ON THU. THIS BRINGS THE COLDEST AIR INTO THE AREA DURING THE MRNG
THU...BUT WITH APRIL SUN...HTG DESPITE THE CLDS SHD MINIMIZE THE
ICING THREAT. LTR IN THE DAY...NEXT WV APCHS AND BNDRY BEGINS TO
LIFT NWRD YET AGAIN...BRINGING AT LEAST THE SWRN PARTS OF THE FCST
AREA BACK INTO THE WRM SECTOR BY 12Z FRI. VIGOROUS UPR WV ALONG
WITH DVLPG LL CONV SHD GENERATE A GOOD SOAKING OF RAIN LATE THU
INTO FRI...WITH THE PSBLTY OF CONV.
DRY SLOT PUSHES THRU THE ENTIRE FCST AREA BY FRI AS THE UPR LOW
DRIFTS NORTH OF THE LAKES. HWVR...ENUF LL MOISTURE AND INSTABILITY
IN THE CAA FOR SOME SCT SHWRS THRU THE END OF THE PD. CAA CONTS
THRU THE END OF THE PD AS WELL WITH H8 TEMPS DROPPING TO NEAR -6C
BY 00Z SUN. SFC TEMPS DO NOT SUPPORT ANY SNOW...AT LEAST THRU THE
END OF THE SHRT TERM.
MEX/MAV GUID CONTD IN GOOD AGREEMENT UNTIL FRI WHEN THE MAV PUSHES
TEMPS HIGHER OF THE NE ZONES...WHILE THE MET KEEPS THE COLD AIR
LOCKED IN. CONTD WITH THE BLEND OF GUID THRU THE END OF THE PD AS
A COMPROMISE FOR THE END OF THE PD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US LIFTS EARLY IN
THE LONG TERM. NW FLOW CONTINUES SAT NGT TO SUN SO POSSIBLY
FLURRIES AND SPRINKLES. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR LATE SUNDAY BEFORE A WARM FRONT LIFTS NE WITH RAIN FOR THE
AREA STARTING SUN NGT. ONCE AGAIN THIS FRONT WILL STALL ACROSS THE
AREA UNTIL WED WHEN A COLD FRONT APPROACHES AHEAD OF A LARGE UL
TROF. MODELS MAY BE TOO FAST WITH THE COLD FRONT SO OFF AND ON
SHOWERS MOST LIKELY SCENARIO.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
A VERY DIFFICULT SOMEWHAT LOW CONFIDENCE FORECAST. BOUNDARY
REMAINS STALLED NEAR THE NY/PA BORDER. LAST ROUND OF SHOWERS AND
ISOLATED THUNDERSTORMS ARE CURRENTLY MOVING THROUGH THE
REGION. AFTER THIS ACTIVITY MOVES EAST AREA SHOULD REMAIN DRY
UNTIL THURSDAY AFTERNOON WHEN SHOWERS WILL BEGIN AGAIN. AT KRME,
MVFR CIGS ARE LIKELY THROUGH THE OVERNIGHT PERIOD WITH IMPROVEMENT
TO VFR THURSDAY MORNING THEN BACK TO MVFR CIGS BY AFTERNOON. AT
KSYR, PRIMARILY IFR CIGS OVERNIGHT WITH IMPROVEMENT TO MVFR BY MID
MORNING. AT KITH, CONDITIONS WILL REMAIN PRIMARILY BELOW AIRPORT
MINS UNTIL MID MORNING WITH IMPROVEMENT TO IFR. AT KELM, PRIMARILY
IFR CIGS OVERNIGHT THEN MVFR ON THURSDAY. AT KBGM, CONDITIONS WILL
DETERIORATE TO BELOW AIRPORT MINS THIS EVENING THEN IMPROVE TO IFR
THURSDAY MORNING. AT KAVP, PRIMARILY MVFR CIGS OVERNIGHT WITH
THUNDERSTORMS LIKELY THROUGH 02Z. CONDITIONS MAY IMPROVE TO VFR
THURSDAY MORNING THEN BACK TO MVFR DURING THE AFTERNOON.
VARIABLE WINDS AT 5 KNOTS OVERNIGHT BECOMING N/NE ON THURSDAY AT
5-8 KNOTS.
.OUTLOOK...
THU NIGHT TO FRI...MVFR WITH PDS OF IFR.
SAT AND SUN...VFR...PSBL MVFR IN MIXED SHWRS.
SUN NGT AND MON...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...CMG/DGM
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...RRM
AREA FORECAST DISCUSSION
NWS RALEIGH NC
247 AM EDT TUE APR 9 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PREVAIL...IN ADVANCE OF A FRONTAL SYSTEM
THAT WILL AFFECT OUR REGION LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 957 PM MONDAY...
WAVE LOCATED OVER WV PRODUCING AN AREA OF MID TO HIGH CLOUDS WILL
TRAVERSE EASTWARD OVERNIGHT... WITH MOST OF THE ASSOCIATED CLOUD
COVER STAYING NORTH OF THE AREA. GFS LOOKS OVERLY AGGRESSIVE SURGING
NEAR 60 DEGREE DEWPOINTS ACROSS THE AREA OVERNIGHT... 00Z OBS
INDICATE DEWPOINTS NEAR 50... MUCH CLOSER TO THE RUC AND NAM
DEPICTIONS. IN THIS CASE... AS WITH LAST NIGHT... BEST LOW LEVEL
MOISTURE AND CHANCES FOR FOG AND LOW STRATUS WILL BE IN THE COASTAL
PLAIN... WITH A FEW PATCHY AREAS POSSIBLE NORTH AND WEST. OVERNIGHT
TEMPERATURES WILL BE A FEW DEGREES WARMER THAN LAST NIGHT... MID
50S... AS TUESDAY 12Z LOW LEVEL THICKNESSES INCREASE AROUND 9 M OVER
THE SAME TIME MONDAY. -SEC
SENSIBLE WEATHER WILL REMAIN WARM AND DRY ACROSS CENTRAL NC AS
SURFACE HIGH ANCHORED OFFSHORE AND A SLOW MOVING LOW PRESSURE SYSTEM
OVER THE SOUTHERN PLAINS MAINTAINS A WARM LOW LEVEL S-SW FLOW OVER
OUR REGION. WLY FLOW BEGINS TO BACK TONIGHT INTO TUESDAY AS A
MID-UPPER LEVEL RIDGE AMPLIFIES NWD OVER THE SE U.S. THIS ADDITIONAL
WARMING ALOFT WILL LEAD TO VERY WARM SFC TEMPS TUESDAY AFTERNOON.
LOW LEVEL THICKNESSES COUPLED WITH A SOUTH-SOUTHWEST BREEZE SUPPORT
AFTERNOON TEMPS NEAR 80 NW TO THE LOWER 80S ELSEWHERE. MIN TEMPS
55-60 TUESDAY NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 230 PM MONDAY...
WEDNESDAY THROUGH THURSDAY:
MID TO UPPER LEVEL RIDGE AXIS IS EXPECTED TO SLOWLY SHIFT OFFSHORE
DURING THIS TIME FRAME... WITH SURFACE HIGH PRESSURE REMAINING
ANCHORED OFFSHORE AND THE NEXT APPROACHING COLD FRONT REMAINING TO
THE WEST OF THE AREA THROUGH THE PERIOD. THIS WILL RESULT IN
CONTINUED ABOVE NORMAL TEMPS... WITH INCREASING CLOUD COVER AND
PRECIP CHANCES BY LATE THURSDAY. STILL EXPECT THE BEST CHANCES FOR
ANY SHOWERS AND OR STORMS TO REMAIN TO THE WEST OF THE AREA THROUGH
THURSDAY AFTERNOON THOUGH... AS THE DEEP TROUGH ALOFT AND ASSOCIATED
COLD FRONT APPROACHES THE AREA FROM THE WEST. HOWEVER... GIVEN
MODELS HAVE TRENDED TO THE FASTER SIDE OF THE GUIDANCE OVER THE PAST
SEVERAL DAYS WITH THIS SYSTEM... WILL GO WITH SLIGHT CHANCE TO LOW
END CHANCE OF SHOWERS AND STORMS FOR LATE THURSDAY AFTERNOON... WITH
THE BEST CHANCE FOR PRECIP EXPECTED OVERNIGHT.
LOW LEVEL THICKNESS VALUES ARE EXPECTED TO PEAK WEDNESDAY AFTERNOON
CLOSE TO 1400 METERS. THIS WILL RESULT IN A WARM AND PARTLY SUNNY
DAY AFTER THE MORNING FOG AND/OR LOW STRATUS BURNS OFF. EXPECT HIGH
TEMPS TO BE IN THE LOWER TO MID 80S... WITH PERHAPS THE WARMEST
TEMPS ACROSS THE NORTHEAST PIEDMONT NEAR THE NC/VA BORDER. LOWS
THURSDAY MORNING WILL HAVE THE SAME FLAVOR... ABOVE NORMAL. EXPECT
LOWS TO BE AROUND 60. HIGHS ON THURSDAY WILL AGAIN BE WARM.
HOWEVER... WE MAY SEE THE STRATUS AND/OR FOG LINGER LONGER AS LOW
MOISTURE IS EXPECTED TO INCREASE FURTHER IN ADVANCE OF THE NEXT
SYSTEM. THUS... WILL GO WITH HIGHS ON THURSDAY IN THE UPPER 70S NW
TO LOWER 80S ELSEWHERE.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 245 AM TUESDAY...
THURSDAY THROUGH FRIDAY NIGHT:
A LOW PRESSURE SYSTEM OVER IOWA 12Z THURSDAY WILL MOVE THROUGH THE
GREAT LAKES REGION THROUGH FRIDAY. AN ASSOCIATED COLD FRONT
EXTENDING SOUTHWARD INTO THE GULF COAST WILL PUSH EASTWARD BRINGING
A CHANCE FOR RAIN AND STORMS. THERE ARE STILL SOME TIMING ISSUES
BETWEEN THE MEDIUM-RANGE MODELS WITH REGARD TO THE FROPA AND PRE-
FRONTAL PRECIP. THE GFS...WHICH HAS A TENDENCY TO BRING SYSTEMS
THROUGH A BIT ON THE QUICK SIDE...IS STILL FASTER THAN THE ECMWF...
AND DEPICTS PRECIP STARTING AS EARLY AS 18Z THURSDAY AND EXITING
MOST OF CENTRAL NC BY 18Z FRIDAY. THE ECMWF IS APPROX 12 HOURS
SLOWER WITH THE ONSET AND ABOUT 6 HOURS BEHIND ON EXIT. GIVEN THE
CURRENT UNCERTAINTY....WILL LIKELY CONTINUE TO INTRODUCE RAIN INTO
THE AREA THURSDAY AFT/EVE...ENDING BY 00Z SATURDAY. AS MENTIONED IN
THE PREVIOUS DISCUSSION...THE DURATION OF RAIN WILL LIKELY BE
NARROWED DOWN OVER THE NEXT DAY OR SO IF THE MODELS BEGIN TO SHOW
BETTER AGREEMENT. IF THE BULK OF THE RAINFALL MOVES THROUGH DURING
THE OVERNIGHT HOURS...AS THE GFS SUGGESTS...CHANCES FOR SEVERE
WEATHER WILL BE LIMITED. ALTHOUGH THE MODELS STILL INDICATE MINIMAL
CAPE VALUES...THEY ALSO CONTINUE TO SUGGEST THE PRESENCE OF A STRONG
LOW-LEVEL JET (40-55 KTS AT 925-850 MB) AND DEWPOINTS IN THE LOW TO
MID 60S...WHICH COULD SUPPORT A FEW STRONG TO SEVERE STORMS AHEAD OF
THE FRONT. BOTH THE GFS AND ECMWF STILL SHOW THE PUSH OF COOLER AIR
WITH A SECONDARY COLD FRONT THAN WITH THE INITIAL FROPA. TIMING OF
THE FROPA WILL IMPACT HIGH AND LOW TEMPS FRIDAY AND SATURDAY...BUT
FOR NOW WILL KEEP TEMPS FROM BOTTOMING OUT UNTIL SATURDAY/SATURDAY
NIGHT. HIGHS THURSDAY IN THE UPPER 70S TO LOW 80S...DECREASING A FEW
DEGREES ON FRIDAY...MID TO UPPER 70S. LOWS THURSDAY NIGHT IN THE LOW
TO MID 60S...WITH COLDER OVERNIGHT LOWS EXPECTED ON FRIDAY NIGHT
BEHIND THE SECONDARY COLD FRONT...MID 40S TO AROUND 50 DEGREES.
SATURDAY THROUGH MONDAY:
HIGH PRESSURE WILL BUILD IN BEHIND THE EXITING LOW PRESSURE SYSTEM
ON SATURDAY AND MIGRATE OVER THE AREA THROUGH SUNDAY AND MOVE
OFFSHORE MONDAY. WITH THE COLD AIR ADVECTION BEHIND THE FRONT...
HIGHS ON SATURDAY WILL BE 7-10 DEGREES LOWER THAN FRIDAY ACROSS THE
AREA...MID 60S TO NEAR 70. HOWEVER...SKIES SHOULD BE MOSTLY CLEAR...
ALLOWING FOR PLENTY OF SUNSHINE. WITH THE COLD AIR AND CLEAR SKIES
EXPECT LOWS SATURDAY NIGHT IN THE LOW TO MID 40S. ALTHOUGH CLOUDS
ARE EXPECTED TO INCREASE SUNDAY AFTERNOON INTO MONDAY...SHOULD SEE A
GRADUAL WARMING TREND...WITH HIGHS IN THE LOW TO MID 70S BY MONDAY
AND OVERNIGHT LOWS IN THE MAINLY IN THE MID 40S SUNDAY NIGHT.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 155 AM TUESDAY...
A PERSISTENCE FORECAST...OF LIFR CONDITIONS AT KFAY AND MVFR AT KRWI
IN THE SEVERAL HOURS LEADING UP TO 12-13Z...WILL GENERALLY BE
FOLLOWED UNTIL PROVEN OTHERWISE. SLIGHTLY HIGHER DEWPOINTS THIS
MORNING VERSUS PREVIOUS DAYS DOES SUGGEST A BIT HIGHER PROBABILITY
OF THE STRATUS/FOG LAYER EDGING NORTHWESTWARD TO NEAR KRDU THIS
MORNING...HOWEVER...SO WILL MONITOR OBSERVATIONAL TRENDS AND AMEND
AS NEEDED. AFTER STRATUS AND FOG BURN OFF THROUGH 13-14Z...VFR
CONDITIONS...IN SUBSIDENT RIDGING ALOFT AND ASSOCIATED UNDERLYING
INFLUENCE OF BERMUDA SURFACE HIGH PRESSURE...WILL PREVAIL THROUGH
THE END OF THE 06Z TAF PERIOD. SOUTH SOUTHWESTERLY SURFACE WINDS
AROUND THE BERMUDA HIGH WILL CONTINUE...BUT BE SOMEWHAT WEAKER AND
LESS GUSTY (IF AT ALL) THAN PREVIOUS AFTERNOONS OWING TO A SLIGHTLY
WEAKER MSL PRESSURE GRADIENT.
OUTLOOK: BERMUDA HIGH PRESSURE...CHARACTERIZED BY AREAS OF FOG
AND/OR STRATUS EACH MORNING...MAINLY AT KFAY AND KRWI...WILL RULE
THROUGH WED NIGHT. FORECAST GUIDANCE SUGGESTS THE DEPTH OF THE LOW
LEVEL MOISTURE WILL PEAK THU MORNING...AT WHICH TIME DEEPER STRATUS
AT ALL TERMINALS IS LIKELY...FOLLOWED BY A PERIOD MVFR RANGE
CEILINGS BETWEEN 13-19Z THU AS THE MOIST LAYER RISES INTO A CUMULUS
FIELD. THE APPROACH AND PASSAGE OF A FRONTAL SYSTEM WILL THEN RESULT
IN A GOOD CHANCE OF SHOWERS AND STORMS AND ASSOCIATED SUB-VFR
CONDITIONS CENTERED AROUND LATE THU-FRI.
&&
.CLIMATE...
IF TEMPERATURES REACH 80 EARLY THIS WEEK...IT WILL BE THE FIRST
80-DEGREE MAXIMUM TEMPERATURE AT KGSO SINCE OCTOBER 24...AND AT KRDU
SINCE OCTOBER 25. KFAY REACHED 80 MORE RECENTLY...WITH AN 83-DEGREE
HIGH ON MARCH 16. OVER THE LAST COUPLE OF YEARS...THE FIRST
80-DEGREE DAYS HAVE BEEN...
KGSO...MARCH 18 2011...AND MARCH 14 2012.
BOTH KRDU AND KFAY...FEBRUARY 27 2011...AND MARCH 1 2012.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...SEC/WSS
SHORT TERM...BSD
LONG TERM...KC
AVIATION...MWS
CLIMATE...DJF
AREA FORECAST DISCUSSION
NWS RALEIGH NC
159 AM EDT TUE APR 9 2013
.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL PREVAIL...IN ADVANCE OF A FRONTAL SYSTEM
THAT WILL AFFECT OUR REGION LATE IN THE WEEK.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
AS OF 957 PM MONDAY...
WAVE LOCATED OVER WV PRODUCING AN AREA OF MID TO HIGH CLOUDS WILL
TRAVERSE EASTWARD OVERNIGHT... WITH MOST OF THE ASSOCIATED CLOUD
COVER STAYING NORTH OF THE AREA. GFS LOOKS OVERLY AGGRESSIVE SURGING
NEAR 60 DEGREE DEWPOINTS ACROSS THE AREA OVERNIGHT... 00Z OBS
INDICATE DEWPOINTS NEAR 50... MUCH CLOSER TO THE RUC AND NAM
DEPICTIONS. IN THIS CASE... AS WITH LAST NIGHT... BEST LOW LEVEL
MOISTURE AND CHANCES FOR FOG AND LOW STRATUS WILL BE IN THE COASTAL
PLAIN... WITH A FEW PATCHY AREAS POSSIBLE NORTH AND WEST. OVERNIGHT
TEMPERATURES WILL BE A FEW DEGREES WARMER THAN LAST NIGHT... MID
50S... AS TUESDAY 12Z LOW LEVEL THICKNESSES INCREASE AROUND 9 M OVER
THE SAME TIME MONDAY. -SEC
SENSIBLE WEATHER WILL REMAIN WARM AND DRY ACROSS CENTRAL NC AS
SURFACE HIGH ANCHORED OFFSHORE AND A SLOW MOVING LOW PRESSURE SYSTEM
OVER THE SOUTHERN PLAINS MAINTAINS A WARM LOW LEVEL S-SW FLOW OVER
OUR REGION. WLY FLOW BEGINS TO BACK TONIGHT INTO TUESDAY AS A
MID-UPPER LEVEL RIDGE AMPLIFIES NWD OVER THE SE U.S. THIS ADDITIONAL
WARMING ALOFT WILL LEAD TO VERY WARM SFC TEMPS TUESDAY AFTERNOON.
LOW LEVEL THICKNESSES COUPLED WITH A SOUTH-SOUTHWEST BREEZE SUPPORT
AFTERNOON TEMPS NEAR 80 NW TO THE LOWER 80S ELSEWHERE. MIN TEMPS
55-60 TUESDAY NIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 230 PM MONDAY...
WEDNESDAY THROUGH THURSDAY:
MID TO UPPER LEVEL RIDGE AXIS IS EXPECTED TO SLOWLY SHIFT OFFSHORE
DURING THIS TIME FRAME... WITH SURFACE HIGH PRESSURE REMAINING
ANCHORED OFFSHORE AND THE NEXT APPROACHING COLD FRONT REMAINING TO
THE WEST OF THE AREA THROUGH THE PERIOD. THIS WILL RESULT IN
CONTINUED ABOVE NORMAL TEMPS... WITH INCREASING CLOUD COVER AND
PRECIP CHANCES BY LATE THURSDAY. STILL EXPECT THE BEST CHANCES FOR
ANY SHOWERS AND OR STORMS TO REMAIN TO THE WEST OF THE AREA THROUGH
THURSDAY AFTERNOON THOUGH... AS THE DEEP TROUGH ALOFT AND ASSOCIATED
COLD FRONT APPROACHES THE AREA FROM THE WEST. HOWEVER... GIVEN
MODELS HAVE TRENDED TO THE FASTER SIDE OF THE GUIDANCE OVER THE PAST
SEVERAL DAYS WITH THIS SYSTEM... WILL GO WITH SLIGHT CHANCE TO LOW
END CHANCE OF SHOWERS AND STORMS FOR LATE THURSDAY AFTERNOON... WITH
THE BEST CHANCE FOR PRECIP EXPECTED OVERNIGHT.
LOW LEVEL THICKNESS VALUES ARE EXPECTED TO PEAK WEDNESDAY AFTERNOON
CLOSE TO 1400 METERS. THIS WILL RESULT IN A WARM AND PARTLY SUNNY
DAY AFTER THE MORNING FOG AND/OR LOW STRATUS BURNS OFF. EXPECT HIGH
TEMPS TO BE IN THE LOWER TO MID 80S... WITH PERHAPS THE WARMEST
TEMPS ACROSS THE NORTHEAST PIEDMONT NEAR THE NC/VA BORDER. LOWS
THURSDAY MORNING WILL HAVE THE SAME FLAVOR... ABOVE NORMAL. EXPECT
LOWS TO BE AROUND 60. HIGHS ON THURSDAY WILL AGAIN BE WARM.
HOWEVER... WE MAY SEE THE STRATUS AND/OR FOG LINGER LONGER AS LOW
MOISTURE IS EXPECTED TO INCREASE FURTHER IN ADVANCE OF THE NEXT
SYSTEM. THUS... WILL GO WITH HIGHS ON THURSDAY IN THE UPPER 70S NW
TO LOWER 80S ELSEWHERE.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 205 PM MONDAY...
THURSDAY NIGHT THROUGH FRIDAY NIGHT:
MEDIUM RANGE MODELS ARE COMING IN BETTER AGREEMENT ON THE NEXT
SYSTEM TO AFFECT THE AREA LATE WEEK... TRENDING TO A BIT FASTER
TIMING. THE GFS (12Z/08TH) AND MOST OF ITS ENSEMBLE MEMBERS
CONTINUES TO BE ON THE FAST SIDE OF THE GUIDANCE WHILE THE LATEST
ECMWF (00Z/08TH) AND ITS RESPECTIVE ENSEMBLE MEMBERS A GOOD 6 TO 9
HOURS SLOWER. WPC HAS ELECTED TO GO WITH BEND BETWEEN THE TWO
OPERATIONAL MODELS... KEEPING IN MIND THE GUIDANCE OVER THE PAST FEW
DAYS HAS TRENDED MORE TO A FASTER MORE PROGRESSIVE SOLUTION. THIS
YIELDS A CLOSED LOW INVOF IA/MO LIFTING NORTHEASTWARD INTO THE GREAT
LAKES REGION THURSDAY EVENING INTO FRIDAY... WITH AN ASSOCIATED
PRIMARY SURFACE LOW TRACKING FROM THE OHIO VALLEY INTO THE GREAT
LAKES AND EVENTUALLY NORTHEAST U.S. BY FRIDAY NIGHT... WITH A
TRAILING COLD FRONT AND ACCOMPANYING BAND OF SHOWERS AND STORMS
CROSSING OUR AREA IN A WEST TO EAST FASHION THURSDAY NIGHT INTO
FRIDAY MORNING/EARLY AFTERNOON. THIS IS A BIT FASTER THAN THE
PREVIOUS FORECAST. FOR NOW WILL SPEED UP THE TIMING A BIT... SHOWING
LIKELY POPS FROM LATE THURSDAY/EARLY FRIDAY MORNING THROUGH EARLY
FRIDAY AFTERNOON. HOWEVER... POPS WILL LIKELY NEED TO BE RAISED AND
FOCUSED OVER A SHORTER TIME FRAME WHEN THE TIMING BECOMES MORE
CLEAR. WRT A SEVERE THREAT... GIVEN THE FASTER TIMING THERE APPEARS
TO BE LESS OF A CHANCE OF SEVERE STORMS... THANKS TO THE OVERNIGHT
INTO MAINLY MORNING TIMING... WITH VERY MINIMAL MLCAPE TO WORK WITH.
HOWEVER... GIVEN DEWPOINTS IN THE MID 60S AND A STRONG LOW LEVEL JET
(WITH 925-850 MB WINDS OF AROUND 40 TO 55 KTS) WE COULD STILL SEE A
FEW STRONG TO SEVERE STORMS ACCOMPANY THE BAND OF SHOWERS AND
STORMS... WITH THE MAIN THREAT FROM DAMAGING WIND GUSTS. MOST OF THE
GUIDANCE HAS THE EFFECTIVE COLD FRONT AND BAND OF SHOWERS AND STORMS
TO THE EAST OF THE RAH CWA BY AROUND 18Z FRIDAY... WITH THE MORE
SIGNIFICANT SECONDARY SHOT OF COLDER/DRY AIR NOT ARRIVING UNTIL
FRIDAY NIGHT WHEN THE SURFACE WINDS SWING AROUND FROM SOUTHWESTERLY
TO NORTHWESTERLY. WE DO NOT EXPECT ANY PRECIP WITH THE SECONDARY
COLD FRONT... JUST AN ACCOMPANYING BAND OF CLOUD COVER (WITH GFS
BUFR SOUNDINGS SHOWING A STRONG SUBSIDENCE INVERSION AROUND 775-800
MB).
TEMPERATURES DURING THIS TIME FRAME WILL BE DRIVEN BY THE ACTUAL
TIME OF THE COLD FRONT. FOR NOW WILL SHOW THE INITIAL COLD FRONT
MOVING INTO THE WESTERN PIEDMONT AROUND 12Z FRIDAY WITH THIS FRONT
TO THE EAST OF THE RAH CWA BY EARLY AFTERNOON. HOWEVER... SOUTHWEST
TO WEST-SOUTHWESTERLY FLOW BEHIND THE INITIAL FRONT AND MOSTLY TO
PARTLY SUNNY SKIES RETURNING BEHIND THE FRONT INITIALLY WILL ALLOW
TEMPS TO WARM QUITE NICELY AGAIN INTO THE MID TO UPPER 70S... AFTER
FRIDAY MORNING LOWS IN THE LOWER TO MID 60S. AS MENTIONED ABOVE THE
SECONDARY COLD FRONT IS EXPECTED TO MOVE THROUGH FRIDAY NIGHT...
WHICH WILL YIELD MUCH COOLER/COLDER LOW TEMPS FOR SATURDAY MORNING.
THUS... EXPECT LOWS BY SATURDAY MORNING WILL RANGE FROM THE MID TO
UPPER 40S... WITH PERHAPS A FEW LOWER 50S IN THE FAR SE.
SATURDAY THROUGH MONDAY:
SURFACE HIGH PRESSURE WILL BUILD ACROSS REGION NEXT WEEKEND... WITH
MOSTLY SUNNY/CLEAR SKIES EXPECTED FOR MOST OF THE WEEKEND... WITH
PERHAPS A BIT MORE CLOUD COVER BY LATE SUNDAY. FORECAST UNCERTAINTY
INCREASES SUNDAY NIGHT INTO MONDAY... AS MEDIUM RANGE MODELS
STRUGGLE WITH BOTH A NORTHERN AND SOUTHERN STREAM SYSTEM. FOR NOW
WILL SHOW CLOUD COVER INCREASING DURING THIS TIME... AND INTRODUCE A
SLIGHT CHANCE OF SHOWERS FOR NEXT MONDAY. EXPECT HIGH TEMPS DURING
THIS PERIOD TO BE NEAR TO SLIGHTLY BELOW NORMAL... GENERALLY IN THE
UPPER 60S TO LOWER 70S.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 155 AM TUESDAY...
A PERSISTENCE FORECAST...OF LIFR CONDITIONS AT KFAY AND MVFR AT KRWI
IN THE SEVERAL HOURS LEADING UP TO 12-13Z...WILL GENERALLY BE
FOLLOWED UNTIL PROVEN OTHERWISE. SLIGHTLY HIGHER DEWPOINTS THIS
MORNING VERSUS PREVIOUS DAYS DOES SUGGEST A BIT HIGHER PROBABILITY
OF THE STRATUS/FOG LAYER EDGING NORTHWESTWARD TO NEAR KRDU THIS
MORNING...HOWEVER...SO WILL MONITOR OBSERVATIONAL TRENDS AND AMEND
AS NEEDED. AFTER STRATUS AND FOG BURN OFF THROUGH 13-14Z...VFR
CONDITIONS...IN SUBSIDENT RIDGING ALOFT AND ASSOCIATED UNDERLYING
INFLUENCE OF BERMUDA SURFACE HIGH PRESSURE...WILL PREVAIL THROUGH
THE END OF THE 06Z TAF PERIOD. SOUTH SOUTHWESTERLY SURFACE WINDS
AROUND THE BERMUDA HIGH WILL CONTINUE...BUT BE SOMEWHAT WEAKER AND
LESS GUSTY (IF AT ALL) THAN PREVIOUS AFTERNOONS OWING TO A SLIGHTLY
WEAKER MSL PRESSURE GRADIENT.
OUTLOOK: BERMUDA HIGH PRESSURE...CHARACTERIZED BY AREAS OF FOG
AND/OR STRATUS EACH MORNING...MAINLY AT KFAY AND KRWI...WILL RULE
THROUGH WED NIGHT. FORECAST GUIDANCE SUGGESTS THE DEPTH OF THE LOW
LEVEL MOISTURE WILL PEAK THU MORNING...AT WHICH TIME DEEPER STRATUS
AT ALL TERMINALS IS LIKELY...FOLLOWED BY A PERIOD MVFR RANGE
CEILINGS BETWEEN 13-19Z THU AS THE MOIST LAYER RISES INTO A CUMULUS
FIELD. THE APPROACH AND PASSAGE OF A FRONTAL SYSTEM WILL THEN RESULT
IN A GOOD CHANCE OF SHOWERS AND STORMS AND ASSOCIATED SUB-VFR
CONDITIONS CENTERED AROUND LATE THU-FRI.
&&
.CLIMATE...
IF TEMPERATURES REACH 80 EARLY THIS WEEK...IT WILL BE THE FIRST
80-DEGREE MAXIMUM TEMPERATURE AT KGSO SINCE OCTOBER 24...AND AT KRDU
SINCE OCTOBER 25. KFAY REACHED 80 MORE RECENTLY...WITH AN 83-DEGREE
HIGH ON MARCH 16. OVER THE LAST COUPLE OF YEARS...THE FIRST
80-DEGREE DAYS HAVE BEEN...
KGSO...MARCH 18 2011...AND MARCH 14 2012.
BOTH KRDU AND KFAY...FEBRUARY 27 2011...AND MARCH 1 2012.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...MWS
NEAR TERM...SEC/WSS
SHORT TERM...BSD
LONG TERM...BSD
AVIATION...MWS
CLIMATE...DJF
AREA FORECAST DISCUSSION
NWS BISMARCK ND
1243 PM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1234 PM CDT TUE APR 9 2013
HIGH CLOUDS ARE THINNING ACROSS THE NORTH AND THAT SHOULD BE GOOD
FOR PARTLY SUNNY SKIES THIS AFTERNOON. COOL FLOW OUT OF THE HIGH
AND SNOW COVER BEING VERY TOUGH ON HIGH TEMPERATURES TODAY.
LOWERED THE FORECAST HIGH ABOUT 2 TO 5 DEGREES ACROSS THE SOUTHWEST
AND EAST CENTRAL. BOWMAN RADAR SHOWS MAINLY FLURRIES NOW...BUT
HETTINGER SHOWERS LIGHT SNOW. DROPPED THE CHANCE OF SNOW AND WILL
GO WITH FLURRIES SOUTH OF BISMARCK AND JAMESTOWN THIS AFTERNOON AS
NO SNOW SHOWING UP BETWEEN ABERDEEN AND MOBRIDGE YET.
UPDATE ISSUED AT 931 AM CDT TUE APR 9 2013
AT 9 AM CDT...COLD SURFACE HIGH REMAINS ACROSS SASKATCHEWAN INTO
MONTANA. LARGE EARL SPRING STORM CONTINUES TO DEVELOP FROM THE
ROCKIES INTO THE CENTRAL PLAINS. ALL BUT THE VERY SOUTHERN TIER
OF COUNTIES WILL SEE SOME HIGH CLOUDINESS. THE SOUTHERN COUNTIES
WILL SEE CONTINUOUS LIGHT SNOW OR FLURRIES. ADDED FLURRIES TO A
LARGER PORTION OF THE SOUTHWEST FOR THE MORNING HOURS..AS BAKER
MONTANA AND BEACH. ARE REPORTING SOME FLURRIES THIS MORNING.
TEMPERATURES LOOK OK SO FAR.
UPDATE ISSUED AT 720 AM CDT TUE APR 9 2013
CURRENT FORECAST ON TRACK AS NORTH WINDS ARE EXPECTED TO KEEP A
VERY SHARP CUTOFF OF THE SNOW SHIELD IN THE EXTREME SOUTH. DID ADD
MENTION OF SOME BLOWING SNOW IN THE SOUTHEAST ALONG TIGHT PRESSURE GRADIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1234 PM CDT TUE APR 9 2013
AT 12 PM CDT SURFACE HIGH PRESSURE ACROSS SASKATCHEWAN AND MONTANA
WAS LARGELY RESPONSIBLE FOR THE VFR CONDITIONS ACROSS THE REGION.
EXPECT VFR TO CONTINUE THROUGH TONIGHT. THEN AFTER 09Z...SEE SOME
LOW LEVEL MOISTURE CREEPING UP THE JAMES RIVER VALLEY AND WENT
WITH BROKEN CEILINGS IN THE MVFR CATEGORY AT KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...RK
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
1238 PM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 1235 PM CDT TUE APR 9 2013
STATUS QUO ON -SN EVOLUTION ACROSS THE FAR SOUTHERN FA. -SN
REMAINS TO THE SOUTH OF OUR FORECAST AREA AND CONFIDENCE PRETTY
HIGH THAT LITTLE WILL FALL ALONG THE BORDER AREA REMAINDER OF
TODAY AND LIKELY TONIGHT. MAINTAINED POPS WHICH WERE LOWERED ON
PREVIOUS UPDATE. TEMPERATURES ANOTHER STORY. FILTERED APRIL SOLAR
IN PLACE BUT TEMPERATURES NOT LIKELY TO MAKE PREVIOUSLY EXPECTED
MAXIMUM TEMPERATURES ESPECIALLY ACROSS THE DVL BASIN. LOWERED
MAXIMUM VALUES SEVERAL DEGREES AND A DEGREE OR SO ELSEWHERE.
ELSEWHERE MINOR ADJUSTMENTS TO SKY COVER.
UPDATE ISSUED AT 935 AM CDT TUE APR 9 2013
FORECAST CHALLENGE FOR UPDATES TODAY WILL BE SNOW CHANCES ALONG
ND/SD/MN BORDER AREA AND TEMPERATURES.
SO FAR DRIER AIR WINNING OUT WITH NORTHERN EDGE OF SNOW BAND WITH
FIRST WAVE FROM BIG STORM SOUTH OF OUR FA AND THE RED BASIN.
EXPECT THESE TRENDS TO CONTINUE TODAY AND HAVE DOUBTS WHETHER ANY
OF THE FAR SOUTHERN FA WILL GET ANY SNOW. DID NOT COMPLETELY PULL
POPS BUT LOWERED TO LOW CHANCES ALONG BORDER AREA TO BE SAFE. VERY
COLD START TODAY HOWEVER WITH COLD ADVECTION OVER AND SOME
FILTERED EARLY APRIL SOLAR TEMPERATURES SHOULD RESPOND. DID NOT
MAKE ANY CHANGES WITH TEMPERATURES BUT WILL MONITOR FOR NEXT
UPDATE. ONLY OTHER CHANGES WERE ADJUSTMENTS TO SKY COVER.
UPDATE ISSUED AT 647 AM CDT TUE APR 9 2013
CONFIDENCE IS INCREASING THAT THE DRY AIRMASS FILTERING INTO THE
REGION FROM THE NORTH WILL WIN AND SNOW CHANCES WILL BE SOUTH OF
THE FA. THE RAP CONTINUES TO TREND SOUTHWARD WITH EACH
RUN...WHICH MAKES SENSE GIVEN DEW POINT VALUES ACROSS THE SOUTHERN
FA IN THE UPPER SINGLE DIGITS (THE 06Z NAM CONTINUES TO PRODUCE
OVER AN INCH OF QPF ACROSS THE SOUTHERN FA THROUGH THIS
AFTERNOON...BUT IS THE ONLY MODEL THIS FAR NORTH). THUS...TRENDED
POPS AND QPF LOWER WITH THIS UPDATE. ALL OTHER ASPECTS OF THE
FORECAST LOOK TO BE ON TRACK THROUGH THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
MAIN CONCERN WILL BE SNOW CHANCES AND AMOUNTS ACROSS THE FAR
SOUTHERN FA. THE NORTHERN EXTENT OF SNOW CHANCES WILL ALSO BE A
CHALLENGE. STRONG LOW LEVEL DRY NORTHERLY FLOW WILL LEAD TO A
SHARP CUTOFF IN SNOW CHANCES. 00Z MODELS HAVE CONTINUED WITH THE
SOUTH TREND IN THE SNOW/NO SNOW LINE. A MID-LEVEL WAVE WILL EJECT
FROM THE MEAN WEST COAST TROUGH LEADING TO STRONG MID-LEVEL WARM
AIR ADVECTION/FRONTOGENESIS NEAR AND SOUTH OF THE SOUTHERN FA. THE
00Z/06Z NAM IS THE FURTHEST NORTH WITH SNOW CHANCES AS ITS FLOW AT
700MB IS MUCH STRONGER (IT IS WORTHWHILE TO NOTE THAT THE SREF
AGREES WITH THE SOUTHERN MODEL CONSENSUS). WILL BRING SNOW
CHANCES INTO THE SOUTHERN FA...BUT WITH DRY LOW LEVEL AIR
FILTERING INTO THIS AREA SNOW AMOUNTS SHOULD REMAIN UNDER AN INCH
(EXCEPT FOR SOUTHERN GRANT COUNTY WHICH COULD GET UP TO 3 INCHES
OR SO). ANOTHER MID-LEVEL WAVE AND ASSOCIATED FORCING WILL EJECT
INTO THIS AREA TONIGHT...ALTHOUGH THE SAME SITUATION APPLIES (AND
MODELS SHOW SIMILAR BIASES). WILL NEED TO CLOSELY MONITOR RADAR
TRENDS AND SHORT TERM MODEL TRENDS...BUT CONFIDENCE IS FAIRLY HIGH
THAT NO HEADLINES WILL BE NEEDED.
THE MAJORITY OF THE FA WILL EXPERIENCE DRY WEATHER...BELOW NORMAL
TEMPERATURES...AND BREEZY NORTH WINDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
WED NIGHT-THUR NIGHT...THE MAIN UPPER LOW WILL PROPAGATE INTO THE
CENTRAL PLAINS WITH A DEFORMATION ZONE SETTING UP INTO THE
SOUTH/SOUTHEAST FA. THE ECMWF REMAINS CONSISTENT INDICATING 5-8
INCHES OF SNOW POSSIBLE ALONG AND SOUTH OF A WAHPETON TO FOSSTON
TO BEMIDJI LINE BY THUR AFTERNOON. THE NAM/GEM/GFS SURFACE RIDGING
IS STRONGER DURING THIS PERIOD...AND KEEP THE MAJORITY OF THE SNOW
SOUTH AND EAST OF THE REGION. CONFIDENCE NOT GREAT IN ANY ONE
SOLUTION...THUS WILL BLEND 50% ECMWF AND 50% OTHER MODELS.
HEADLINES MAY BE NEEDED IF OTHER MODELS BEGIN TO TREND TOWARD THE
ECMWF SOLUTION. TEMPERATURES WILL REMAIN WELL BELOW NORMAL VALUES.
FRIDAY-MONDAY...BY THE END OF THE WEEK THE SLOWER ECMWF LINGERS
THE 500MB TROUGH THRU FRIDAY WHEREAS THE GFS IS MORE PROGRESSIVE
WITH WEAK 500MB RIDGING AHEAD OF THE NEXT WAVE. BOTH MODELS
INDICATE THE COOL LOWER THERMAL PROFILE WITH MAX TEMPS IN THE 30S
AND 40S... WITH GFS BRINGING PCPN WITH SHORT WAVE SAT. A MORE
ROBUST WAVE IS PROGGED TO QUICKLY MOVE EAST IN THE NEARLY ZONAL
FAST NORTHERN STREAM FROM THE PAC NW BRINGING PCPN TO THE REGION
EARLY SUNDAY. A RAIN AND SNOW MIX IS EXPECTED AS THE THERMAL
PROFILE WARMS AHEAD OF THE SYSTEM WITH A WAA BAND ON RAIN AND SNOW
ON THE DEF ZONE AS COLD AIR ENTRAINS ON THE BACKSIDE. MAX TEMPS
CONTINUE TO BE 10 TO 20 DEGREES BLO NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z WEDNESDAY AFTERNOON)
ISSUED AT 1236 PM CDT TUE APR 9 2013
BRIEF INTERVAL OF LOWER CLOUDINESS EMANATING FROM UPPER MIDWEST
SYSTEM HAS MOVED AWAY FROM KFAR...LOOK FOR CIRRUS TO PREVAIL FROM
KDVL-KFGF-KTVF THROUGH PERIOD WITH SOME MID CLOUD ELSEWHERE. WINDS
TO REMAIN NORTHERLY NEAR 15 KT THROUGH THE EVENING...EASING BELOW 10
KTS TONIGHT.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/JK
AVIATION...WJB
AREA FORECAST DISCUSSION
NWS BISMARCK ND
942 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 931 AM CDT TUE APR 9 2013
AT 9 AM CDT...COLD SURFACE HIGH REMAINS ACROSS SASKATCHEWAN INTO
MONTANA. LARGE EARL SPRING STORM CONTINUES TO DEVELOP FROM THE
ROCKIES INTO THE CENTRAL PLAINS. ALL BUT THE VERY SOUTHERN TIER
OF COUNTIES WILL SEE SOME HIGH CLOUDINESS. THE SOUTHERN COUNTIES
WILL SEE CONTINUOUS LIGHT SNOW OR FLURRIES. ADDED FLURRIES TO A
LARGER PORTION OF THE SOUTHWEST FOR THE MORNING HOURS..AS BAKER
MONTANA AND BEACH. ARE REPORTING SOME FLURRIES THIS MORNING.
TEMPERATURES LOOK OK SO FAR.
UPDATE ISSUED AT 720 AM CDT TUE APR 9 2013
CURRENT FORECAST ON TRACK AS NORTH WINDS ARE EXPECTED TO KEEP A
VERY SHARP CUTOFF OF THE SNOW SHIELD IN THE EXTREME SOUTH. DID ADD
MENTION OF SOME BLOWING SNOW IN THE SOUTHEAST ALONG TIGHT PRESSURE GRADIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 940 AM CDT TUE APR 9 2013
HIGH PRESSURE WILL DOMINATE THE WEATHER FOR THE REGION TUESDAY.
THERE ARE WIDESPREAD HUIGH CLOUDS...SOME THINNING NORTH. VFR
CONDITIONS WILL PREVAIL TODAY AS DRY NORTHERLY FLOW OUT OF THE
HIGH SHOULD KEEP LIGHT SNOW CONFINED SOUTH OF KDIK-KBIS-KJMS.
ALTHOUGH SOME FLURRIES ARE POSSIBLE AT KDIK THROUGH 17Z.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...LTH
LONG TERM...RK
AVIATION...WAA
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
937 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 935 AM CDT TUE APR 9 2013
FORECAST CHALLENGE FOR UPDATES TODAY WILL BE SNOW CHANCES ALONG
ND/SD/MN BORDER AREA AND TEMPERATURES.
SO FAR DRIER AIR WINNING OUT WITH NORTHERN EDGE OF SNOW BAND WITH
FIRST WAVE FROM BIG STORM SOUTH OF OUR FA AND THE RED BASIN.
EXPECT THESE TRENDS TO CONTINUE TODAY AND HAVE DOUBTS WHETHER ANY
OF THE FAR SOUTHERN FA WILL GET ANY SNOW. DID NOT COMPLETELY PULL
POPS BUT LOWERED TO LOW CHANCES ALONG BORDER AREA TO BE SAFE. VERY
COLD START TODAY HOWEVER WITH COLD ADVECTION OVER AND SOME
FILTERED EARLY APRIL SOLAR TEMPERATURES SHOULD RESPOND. DID NOT
MAKE ANY CHANGES WITH TEMPERATURES BUT WILL MONITOR FOR NEXT
UPDATE. ONLY OTHER CHANGES WERE ADJUSTMENTS TO SKY COVER.
UPDATE ISSUED AT 647 AM CDT TUE APR 9 2013
CONFIDENCE IS INCREASING THAT THE DRY AIRMASS FILTERING INTO THE
REGION FROM THE NORTH WILL WIN AND SNOW CHANCES WILL BE SOUTH OF
THE FA. THE RAP CONTINUES TO TREND SOUTHWARD WITH EACH
RUN...WHICH MAKES SENSE GIVEN DEW POINT VALUES ACROSS THE SOUTHERN
FA IN THE UPPER SINGLE DIGITS (THE 06Z NAM CONTINUES TO PRODUCE
OVER AN INCH OF QPF ACROSS THE SOUTHERN FA THROUGH THIS
AFTERNOON...BUT IS THE ONLY MODEL THIS FAR NORTH). THUS...TRENDED
POPS AND QPF LOWER WITH THIS UPDATE. ALL OTHER ASPECTS OF THE
FORECAST LOOK TO BE ON TRACK THROUGH THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
MAIN CONCERN WILL BE SNOW CHANCES AND AMOUNTS ACROSS THE FAR
SOUTHERN FA. THE NORTHERN EXTENT OF SNOW CHANCES WILL ALSO BE A
CHALLENGE. STRONG LOW LEVEL DRY NORTHERLY FLOW WILL LEAD TO A
SHARP CUTOFF IN SNOW CHANCES. 00Z MODELS HAVE CONTINUED WITH THE
SOUTH TREND IN THE SNOW/NO SNOW LINE. A MID-LEVEL WAVE WILL EJECT
FROM THE MEAN WEST COAST TROUGH LEADING TO STRONG MID-LEVEL WARM
AIR ADVECTION/FRONTOGENESIS NEAR AND SOUTH OF THE SOUTHERN FA. THE
00Z/06Z NAM IS THE FURTHEST NORTH WITH SNOW CHANCES AS ITS FLOW AT
700MB IS MUCH STRONGER (IT IS WORTHWHILE TO NOTE THAT THE SREF
AGREES WITH THE SOUTHERN MODEL CONSENSUS). WILL BRING SNOW
CHANCES INTO THE SOUTHERN FA...BUT WITH DRY LOW LEVEL AIR
FILTERING INTO THIS AREA SNOW AMOUNTS SHOULD REMAIN UNDER AN INCH
(EXCEPT FOR SOUTHERN GRANT COUNTY WHICH COULD GET UP TO 3 INCHES
OR SO). ANOTHER MID-LEVEL WAVE AND ASSOCIATED FORCING WILL EJECT
INTO THIS AREA TONIGHT...ALTHOUGH THE SAME SITUATION APPLIES (AND
MODELS SHOW SIMILAR BIASES). WILL NEED TO CLOSELY MONITOR RADAR
TRENDS AND SHORT TERM MODEL TRENDS...BUT CONFIDENCE IS FAIRLY HIGH
THAT NO HEADLINES WILL BE NEEDED.
THE MAJORITY OF THE FA WILL EXPERIENCE DRY WEATHER...BELOW NORMAL
TEMPERATURES...AND BREEZY NORTH WINDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
WED NIGHT-THUR NIGHT...THE MAIN UPPER LOW WILL PROPAGATE INTO THE
CENTRAL PLAINS WITH A DEFORMATION ZONE SETTING UP INTO THE
SOUTH/SOUTHEAST FA. THE ECMWF REMAINS CONSISTENT INDICATING 5-8
INCHES OF SNOW POSSIBLE ALONG AND SOUTH OF A WAHPETON TO FOSSTON
TO BEMIDJI LINE BY THUR AFTERNOON. THE NAM/GEM/GFS SURFACE RIDGING
IS STRONGER DURING THIS PERIOD...AND KEEP THE MAJORITY OF THE SNOW
SOUTH AND EAST OF THE REGION. CONFIDENCE NOT GREAT IN ANY ONE
SOLUTION...THUS WILL BLEND 50% ECMWF AND 50% OTHER MODELS.
HEADLINES MAY BE NEEDED IF OTHER MODELS BEGIN TO TREND TOWARD THE
ECMWF SOLUTION. TEMPERATURES WILL REMAIN WELL BELOW NORMAL VALUES.
FRIDAY-MONDAY...BY THE END OF THE WEEK THE SLOWER ECMWF LINGERS
THE 500MB TROUGH THRU FRIDAY WHEREAS THE GFS IS MORE PROGRESSIVE
WITH WEAK 500MB RIDGING AHEAD OF THE NEXT WAVE. BOTH MODELS
INDICATE THE COOL LOWER THERMAL PROFILE WITH MAX TEMPS IN THE 30S
AND 40S... WITH GFS BRINGING PCPN WITH SHORT WAVE SAT. A MORE
ROBUST WAVE IS PROGGED TO QUICKLY MOVE EAST IN THE NEARLY ZONAL
FAST NORTHERN STREAM FROM THE PAC NW BRINGING PCPN TO THE REGION
EARLY SUNDAY. A RAIN AND SNOW MIX IS EXPECTED AS THE THERMAL
PROFILE WARMS AHEAD OF THE SYSTEM WITH A WAA BAND ON RAIN AND SNOW
ON THE DEF ZONE AS COLD AIR ENTRAINS ON THE BACKSIDE. MAX TEMPS
CONTINUE TO BE 10 TO 20 DEGREES BLO NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 647 AM CDT TUE APR 9 2013
EXPECT VFR CONDITIONS IN ALL AREAS AS DRY NORTHERLY LOW LEVEL FLOW
CONTINUES TO SPREAD A DRY AIRMASS INTO THE REGION. SNOW WILL
REMAIN SOUTH OF ALL TAF SITES THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...VOELKER
SHORT TERM...TG
LONG TERM...TG/JK
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
745 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 720 AM CDT TUE APR 9 2013
CURRENT FORECAST ON TRACK AS NORTH WINDS ARE EXPECTED TO KEEP A
VERY SHARP CUTOFF OF THE SNOW SHIELD IN THE EXTREME SOUTH. DID ADD
MENTION OF SOME BLOWING SNOW IN THE SOUTHEAST ALONG TIGHT PRESSURE GRADIENT.
&&
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 405 AM CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 720 AM CDT TUE APR 9 2013
MAINLY VFR CONDITIONS TODAY AS DRY NORTHERLY FLOW SHOULD KEEP
LIGHT SNOW CONFINED SOUTH OF KDIK-KBIS-KJMS. MVFR FOG IS POSSIBLE OVERNIGHT
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...RK
SHORT TERM...LTH
LONG TERM...RK
AVIATION...RK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
647 AM CDT TUE APR 9 2013
.UPDATE...
ISSUED AT 647 AM CDT TUE APR 9 2013
CONFIDENCE IS INCREASING THAT THE DRY AIRMASS FILTERING INTO THE
REGION FROM THE NORTH WILL WIN AND SNOW CHANCES WILL BE SOUTH OF
THE FA. THE RAP CONTINUES TO TREND SOUTHWARD WITH EACH
RUN...WHICH MAKES SENSE GIVEN DEW POINT VALUES ACROSS THE SOUTHERN
FA IN THE UPPER SINGLE DIGITS (THE 06Z NAM CONTINUES TO PRODUCE
OVER AN INCH OF QPF ACROSS THE SOUTHERN FA THROUGH THIS
AFTERNOON...BUT IS THE ONLY MODEL THIS FAR NORTH). THUS...TRENDED
POPS AND QPF LOWER WITH THIS UPDATE. ALL OTHER ASPECTS OF THE
FORECAST LOOK TO BE ON TRACK THROUGH THIS AFTERNOON.
&&
.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
MAIN CONCERN WILL BE SNOW CHANCES AND AMOUNTS ACROSS THE FAR
SOUTHERN FA. THE NORTHERN EXTENT OF SNOW CHANCES WILL ALSO BE A
CHALLENGE. STRONG LOW LEVEL DRY NORTHERLY FLOW WILL LEAD TO A
SHARP CUTOFF IN SNOW CHANCES. 00Z MODELS HAVE CONTINUED WITH THE
SOUTH TREND IN THE SNOW/NO SNOW LINE. A MID-LEVEL WAVE WILL EJECT
FROM THE MEAN WEST COAST TROUGH LEADING TO STRONG MID-LEVEL WARM
AIR ADVECTION/FRONTOGENESIS NEAR AND SOUTH OF THE SOUTHERN FA. THE
00Z/06Z NAM IS THE FURTHEST NORTH WITH SNOW CHANCES AS ITS FLOW AT
700MB IS MUCH STRONGER (IT IS WORTHWHILE TO NOTE THAT THE SREF
AGREES WITH THE SOUTHERN MODEL CONSENSUS). WILL BRING SNOW
CHANCES INTO THE SOUTHERN FA...BUT WITH DRY LOW LEVEL AIR
FILTERING INTO THIS AREA SNOW AMOUNTS SHOULD REMAIN UNDER AN INCH
(EXCEPT FOR SOUTHERN GRANT COUNTY WHICH COULD GET UP TO 3 INCHES
OR SO). ANOTHER MID-LEVEL WAVE AND ASSOCIATED FORCING WILL EJECT
INTO THIS AREA TONIGHT...ALTHOUGH THE SAME SITUATION APPLIES (AND
MODELS SHOW SIMILAR BIASES). WILL NEED TO CLOSELY MONITOR RADAR
TRENDS AND SHORT TERM MODEL TRENDS...BUT CONFIDENCE IS FAIRLY HIGH
THAT NO HEADLINES WILL BE NEEDED.
THE MAJORITY OF THE FA WILL EXPERIENCE DRY WEATHER...BELOW NORMAL
TEMPERATURES...AND BREEZY NORTH WINDS.
.LONG TERM...(WEDNESDAY NIGHT THROUGH MONDAY)
ISSUED AT 332 AM CDT TUE APR 9 2013
WED NIGHT-THUR NIGHT...THE MAIN UPPER LOW WILL PROPAGATE INTO THE
CENTRAL PLAINS WITH A DEFORMATION ZONE SETTING UP INTO THE
SOUTH/SOUTHEAST FA. THE ECMWF REMAINS CONSISTENT INDICATING 5-8
INCHES OF SNOW POSSIBLE ALONG AND SOUTH OF A WAHPETON TO FOSSTON
TO BEMIDJI LINE BY THUR AFTERNOON. THE NAM/GEM/GFS SURFACE RIDGING
IS STRONGER DURING THIS PERIOD...AND KEEP THE MAJORITY OF THE SNOW
SOUTH AND EAST OF THE REGION. CONFIDENCE NOT GREAT IN ANY ONE
SOLUTION...THUS WILL BLEND 50% ECMWF AND 50% OTHER MODELS.
HEADLINES MAY BE NEEDED IF OTHER MODELS BEGIN TO TREND TOWARD THE
ECMWF SOLUTION. TEMPERATURES WILL REMAIN WELL BELOW NORMAL VALUES.
FRIDAY-MONDAY...BY THE END OF THE WEEK THE SLOWER ECMWF LINGERS
THE 500MB TROUGH THRU FRIDAY WHEREAS THE GFS IS MORE PROGRESSIVE
WITH WEAK 500MB RIDGING AHEAD OF THE NEXT WAVE. BOTH MODELS
INDICATE THE COOL LOWER THERMAL PROFILE WITH MAX TEMPS IN THE 30S
AND 40S... WITH GFS BRINGING PCPN WITH SHORT WAVE SAT. A MORE
ROBUST WAVE IS PROGGED TO QUICKLY MOVE EAST IN THE NEARLY ZONAL
FAST NORTHERN STREAM FROM THE PAC NW BRINGING PCPN TO THE REGION
EARLY SUNDAY. A RAIN AND SNOW MIX IS EXPECTED AS THE THERMAL
PROFILE WARMS AHEAD OF THE SYSTEM WITH A WAA BAND ON RAIN AND SNOW
ON THE DEF ZONE AS COLD AIR ENTRAINS ON THE BACKSIDE. MAX TEMPS
CONTINUE TO BE 10 TO 20 DEGREES BLO NORMAL FOR MID APRIL.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 647 AM CDT TUE APR 9 2013
EXPECT VFR CONDITIONS IN ALL AREAS AS DRY NORTHERLY LOW LEVEL FLOW
CONTINUES TO SPREAD A DRY AIRMASS INTO THE REGION. SNOW WILL
REMAIN SOUTH OF ALL TAF SITES THROUGH THE PERIOD.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
UPDATE...TG
SHORT TERM...TG
LONG TERM...TG/JK
AVIATION...TG
AREA FORECAST DISCUSSION
NWS BISMARCK ND
405 AM CDT TUE APR 9 2013
.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 405 CDT TUE APR 9 2013
THE MAIN FORECAST CHALLENGE FOR THE SHORT TERM PERIOD IS THE
POTENTIAL FOR ACCUMULATING SNOW ACROSS THE SOUTHERN TIER OF
COUNTIES. THE 00Z MODEL GUIDANCE IS IN GOOD AGREEMENT...AND HAVE
UTILIZED A BLEND OF GUIDANCE.
COLD SURFACE HIGH PRESSURE CONTINUES TO BUILD SOUTH FROM CANADA OVER
THE NORTHERN PLAINS THIS MORNING...ALLOWING FOR A COLD AND DRY
AIRMASS TO CONTINUE TO MOVE SOUTH INTO THE REGION. SUBSIDENCE
ASSOCIATED WITH THE SURFACE HIGH PRESSURE...CONTINUES TO ERODE THE
NORTHERN EDGE OF LOW LEVEL STRATUS ALONG INTERSTATE 94. SOUTH OF
INTERSTATE 94...LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS
MOVING NORTH INTO THE FAR SOUTH. THERE HAVE BEEN SOME REPORTS OF
LIGHT SNOW THIS MORNING FROM HETTINGER. THE NORTHWARD PROGRESSION OF
THE LIGHT SNOW WILL BE SUPPRESSED AS IT MOVES INTO THE DRY AIRMASS
ASSOCIATED WITH THE AFOREMENTIONED HIGH.
THE LATEST 07Z RAP GUIDANCE CONTINUES TO BE AGGRESSIVE WITH THE QPF
AMOUNTS ACROSS THE SOUTHWEST...KEEPING UPWARDS OF A TENTH OF AN INCH
ACROSS BOWMAN AND ADAMS COUNTIES. THE LATEST 00Z ECMWF RUN HAS COME
IN DRIER THAN THE PREVIOUS RUN...ALIGNING MORE WITH THE 00Z GFS AND
NAM SOLUTIONS. A SHARP GRADIENT OF PRECIPITATION/QPF AMOUNTS WILL
DEVELOP ALONG THE ND/SD STATE BORDER TODAY AND TONIGHT...WITH THE
HEAVIEST QPF FORECAST FOR SOUTH DAKOTA. SNOWFALL TOTALS WILL NOT
EVEN COME CLOSE TO MINIMUM ADVISORY CRITERIA...WITH ONLY A FEW
TENTHS SOUTH OF INTERSTATE 94...CLIMBING TO NEAR AN INCH AT THE
ND/SD STATE BORDER. AS A RESULT...WILL NOT NEED ANY WINTER WEATHER
HEADLINES FOR THIS LATEST ROUND OF SNOW FOR THE SOUTHERN COUNTIES.
TEMPERATURES WILL BE 20 TO 25 DEGREES BELOW NORMAL DURING THE
PERIOD. HIGHS WILL STRUGGLE TO REACH THE FREEZING MARK...AS HIGHS
WILL BE ONLY IN THE 20S. ANOTHER COLD NIGHT IS IN STORE FOR
TONIGHT...AS LOWS WILL RANGE FROM 5 ABOVE ACROSS THE NORTH TO NEAR
20 IN THE SOUTH CENTRAL. WIND CHILL VALUES MAY APPROACH ADVISORY
CRITERIA THIS MORNING FOR THE NORTH CENTRAL...BUT THIS WILL BE SHORT
LIVED AS WINDS ARE EXPECTED DISSIPATE THIS MORNING.
.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 405 CDT TUE APR 9 2013
THE MAIN FORECAST ISSUE IS THE EVOLUTION OF THE CENTRAL CONUS UPPER
TROUGH AND ASSOCIATED IMPACT ON WEATHER ACROSS WESTERN AND CENTRAL
NORTH DAKOTA. ON WEDNESDAY...MODEL AGREEMENT ON THE INITIAL
POSITION OF THE LOW SUPPORTS BOOSTING POPS ACROSS THE EXTREME
SOUTHERN COUNTIES. BASED ON CONSENSUS QPF...AND INCH OR SO OF NEW
SNOW WILL BE POSSIBLE DURING THE DAY...AND PERHAPS AN ADDITIONAL
INCH OR TWO WEDNESDAY NIGHT IN THE SOUTHERN JAMES RIVER VALLEY.
EVEN THOUGH TOTAL AMOUNTS MIGHT LEAN TOWARD ADVISORY LEVELS SOME
LOCATIONS...THE EXPECTED LONG DURATION OF THE LIGHT SNOW PRECLUDES
ANY HEADLINES. ON THURSDAY...THE LOW WILL BEGIN TO PUSH NORTHEAST
AND ADDITIONAL LIGHT SNOW MAY GLANCE THE EXTREME SOUTHEAST. OVER
THE COMING WEEKEND...MORE ACTIVE ZONAL FLOW WILL BECOME ESTABLISHED
AND ANOTHER COMPACT UPPER TROUGH IS EXPECTED TO DIG INTO THE
REGION. ACCUMULATING SNOW AND A WINTRY MIX WILL AGAIN BE POSSIBLE.
TEMPERATURES THROUGH THE LONG TERM PERIOD SHOULD PREVENT ANY RAPID
SNOWMELT RUNOFF ACROSS THE SOURIS RIVER BASIN...WITH HIGHS WARMING
INTO THE MID TO UPPER 30S BY FRIDAY AND OVERNIGHT LOWS BELOW FREEZING.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY NIGHT)
ISSUED AT 405 AM CDT TUE APR 9 2013
COLD HIGH PRESSURE OVER SOUTHERN CANADA WILL BUILD INTO NORTHWEST
NORTH DAKOTA. AS A RESULT...VFR CONDITIONS WILL PREVAIL THROUGH THE
06 UTC TAF PERIOD. THE MAIN AVIATION HAZARD WILL BE GUSTY NORTH
WINDS. ANOTHER WINTER STORM WILL TRACK ACROSS WYOMING AND SOUTH
DAKOTA TUESDAY. THIS WILL ALSO BRING SNOW TO THE FAR SOUTH
TUESDAY...BUT SHOULD REMAIN SOUTH OF THE KDIK-KBIS-KJMS TERMINALS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...LTH
LONG TERM...RK
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS TULSA OK
1128 AM CDT TUE APR 9 2013
...UPDATE...
.DISCUSSION...
STRONG COLD FRONT WHICH HAS PASSED THROUGH MUCH OF THE TEXAS
PANHANDLE AND PORTIONS OF NW OK HAS CONTINUED TO SWEEP STEADILY
SOUTHEASTWARD THROUGH THE MORNING AIDED BY A BROAD REGION OF
STRONG PRESSURE RISES. CURRENT OBSERVATIONS AND 12Z UPPER AIR DATA
REVEAL THE STRENGTH OF THE ADVANCING COLD AIRMASS WITH THE CURRENT
FRONTAL POSITION A BIT FASTER THAN THE RECENT 12Z NAM...AND WITH
THE 12Z GFS HAVING NOTABLE INITIALIZATION ERRORS WITH THE
MAGNITUDE OF THE COLD AIR. RECENT RAP RUNS ALONG WITH LCL WRF RUNS
HAVE CONTINUED TO TREND FASTER WITH THE FRONTAL PROGRESSION INTO
EASTERN OK AND THE UPDATED FORECAST WILL REFLECT THIS FASTER
ARRIVAL.
THE PRE-FRONTAL WARM SECTOR REMAINS STRONGLY CAPPED PER 12Z
REGIONAL SOUNDINGS AND APPEARANCE OF VISIBLE SATELLITE IMAGERY.
FORECAST SOUNDINGS ACROSS THE WARM SECTOR MAINTAIN A SIZABLE WARM
LAYER AND BREAKING IT WOULD TAKE APPRECIABLE SFC HEATING AND/OR
LOW LEVEL CONVERGENCE WHICH IS NOT LIKELY AHEAD OF THE FRONT...THUS
THE AFTERNOON PRECIP CHANCES WERE LOWERED BELOW MENTIONABLE
LEVELS.
CONVECTION WILL EXPAND AND INTENSIFY ALONG THE FRONTAL BOUNDARY AS
IT PUSHES SOUTHEASTWARD THIS AFTERNOON AND EVENING...WITH
AVAILABLE INSTABILITY AND SHEAR WITHIN THE FRONTAL ZONE SUPPORTING
A RISK OF SEVERE WEATHER. ANY PRE-FRONTAL CELLULAR STORMS WILL
LIKELY REMAIN RATHER LIMITED IN BOTH COVERAGE AND DURATION AS THE
STRONG FRONTAL SURGE INTERCEPTS ANTICIPATED STORM MOTIONS WITHIN A
SHORT TIME WINDOW.
ADDITIONALLY...GIVEN THE FORECAST WIND FIELDS AND FASTER FRONTAL
SURGE THE CONVECTION WILL QUICKLY FOCUS IN THE POST FRONTAL ZONE
WHICH IS ALREADY EVIDENT ACROSS WEST TEXAS. THIS AGAIN WOULD FAVOR
A NARROW ZONE OF SFC BASED CONVECTION WITHIN THE FRONTAL ZONE
WHICH WOULD ALLOW FOR POCKETS OF DAMAGING WIND POTENTIAL...WITH
THE SVR MODE QUICKLY TRANSITIONING TO LARGE HAIL BEHIND THE FRONT.
THE TORNADIC RISK APPEARS RATHER SMALL ESPECIALLY FOR ANY DISCRETE
SUPERCELLS ACROSS THE FORECAST AREA. ALSO...SHEAR VECTORS ARE NOT
OVERLY SUPPORTIVE OF QLCS TORNADOES BUT THIS POTENTIAL WILL BE
MONITORED GIVEN THE INCREASINGLY STRONG LOW LEVEL SHEAR TONIGHT.
THE UPDATED FORECAST WILL ADJUST WINDS THIS EVENING...AND MAINTAIN
FORECAST HIGH TEMPS WHICH EXPECT AT LEAST SOME BREAKS IN THE
AFTERNOON CLOUDS. PRECIP AMOUNTS WILL ALSO BE INCREASED FOR LATE
TONIGHT ACROSS NE OK.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 79 39 46 30 / 10 90 80 10
FSM 82 56 57 34 / 10 80 90 30
MLC 80 41 46 31 / 10 90 80 10
BVO 78 36 47 28 / 10 90 80 10
FYV 77 55 56 33 / 10 80 90 30
BYV 78 59 61 34 / 10 80 90 30
MKO 79 43 46 30 / 10 90 80 20
MIO 78 44 45 30 / 10 90 90 20
F10 79 39 47 30 / 10 90 80 10
HHW 80 56 56 34 / 10 90 80 20
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...NONE.
AR...NONE.
&&
$$
SHORT TERM...07
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
608 PM EDT TUE APR 9 2013
.SYNOPSIS...
A WEAK FRONT WILL WAGGLE TO THE NORTH AND SOUTH OVER THE STATE
THROUGH THE NEXT FEW DAYS. THIS FRONT WILL PROVIDE A FOCUS FOR
PERIODIC OF SHOWERS AND STORMS THROUGH THURSDAY. A DYNAMIC STORM
SYSTEM CROSSING THE CENTRAL UNITED STATES WILL SEND A STRONG COLD
FRONT ACROSS THE REGION ON FRIDAY ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES WILL
BRIEFLY COOL DOWN BEHIND THE FRONT INTO THE UPCOMING WEEKEND
BEFORE REBOUNDING ABOVE NORMALS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CUMULUS CONGESTUS OVER WRN PA AT 3 PM...BUT NOTHING BREAKING
THROUGH THE CAP. LATEST RUC/RAP AND HRRR DO CONTINUE TO POINT
TOWARD SOME CONVECTION DEVELOPING THIS AFTN/EVENING IN THE SW AND
SLIDING EAST. HOWEVER...AIR IS DRY N OF RTE 22...ESP NE OF AOO.
FRONT WILL WAGGLE A BIT FARTHER N THIS EVENING...AND BEST THERMAL
GRADIENT WILL BE TO THE NORTH OF THE AREA TONIGHT. WILL STILL GIVE
A HIGH CHC/LIKELY POP TO THE NRN THIRD OF THE AREA...BUT TAPER IT
OFF TO NIL AROUND THE TURNPIKE. UNCERTAINTY IN THE CONVECTIVE
DEVELOPMENT WITH VERY WEAK FORCING IS THE BIGGEST FACTOR FOR A
WIDE RANGE IN POPS...AND CONTINUE LOW CHC POPS IN THE SRN HALF OF
THE AREA. CONFIDENCE IS HIGHEST IN THE N. WILL ALSO MENTION T FOR
THE N WHERE MSTR/DEWPOINTS DO POOL UP AND WILL BE CLOSER TO THE
DYNAMICS/FORCING. MINS WILL BE WILDLY MILD WITH SUCH A WARM START
TO THE NIGHT. CLEARING MOST LIKELY IN THE S/DOWNSLOPE AREAS TO SE
OF IPT/UNV/AOO. BUT LOWER CLOUDS SHOULD MAKE THEIR WAY DOWN TO
THAT LINE LATER TONIGHT AS THE CONVECTION/RAIN TO THE NORTH SHOVES
COOLER AIR SOUTHWARD UNDER THE VERY STRONG INVERSION.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AGAIN...THE PATHWAY FOR THE CONVECTION POSSIBLE ON WED AND
WED NIGHT WILL BE ACROSS THE NORTH. BUT...CANNOT RULE OUT THE STRAY
SHOWER OR TWO IN THE SOUTH. TIMING OF ANY FEATURES WHICH WILL
PROVIDE COHERENT FORCING REMAINS LOW AND MOST LIKELY TIED TO DEAD
UPSTREAM CONVECTION. THUS...POPS ARE BROAD-BRUSHED FOR MUCH OF THIS
SHORT TERM PD. TEMPS ARE HIGHLY DEPENDENT ON THE CLOUD COVER AND
HOW MUCH MIXING CAN OCCUR ON WED. WILL COUNT ON GOOD MIXING TO THE
SOUTH OF I-80 TO ALLOW TEMPS TO GET BACK TO WHERE THEY ARE THIS
AFTN...OR EVEN SLIGHTLY HIGHER. BUT TEMPS WILL PROBABLY BE A FEW
DEGS COOLER IN THE W AND N. MINS AGAIN WED NIGHT WILL BE VERY
MILD. BUT MORE COOL AIR WILL LIKELY WORK SOUTHWARD INTO THE NRN
MTS AND TAKE THE TEMPS WELL DOWN INTO THE 40S. BUT STILL SLIGHTLY
ABV NORMS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AMPLIFIED UPPER-LEVEL TROUGH WILL BE ON THE MOVE OVER THE CENTRAL
CONUS...CONSISTING OF TWO PROMINENT SHORTWAVE IMPULSES. THE
DYNAMIC SYSTEM WILL TAKE ON A NEGATIVE TILT AS IT CROSSES THE MS
RVR WITH THE BASAL IMPULSE ACCELERATING E/NEWD FROM SRN TX TOWARDS
THE CENTRAL APPALACHIANS. THE EVOLVING FRONTAL SYSTEM WILL
FEATURE AN OCCLUDING CYCLONE OVER THE GRT LKS WITH SECONDARY
TRIPLE PT LOW DEVELOPMENT IN THE UPPER OH VLY. MODEL DATA
INDICATES A SQUALL LINE/BAND OF MOD-HVY RAFL WILL ACCOMPANY THE
TRAILING COLD FRONT WHICH SHOULD BE APPROACHING/CROSSING THE WRN
PA MTNS BY 12Z FRIDAY. THE GFS IS ABOUT 6HRS FASTER THAN THE EC
AND CANADIAN WITH THE EWD PROGRESSION OF THE COLD FRONTAL RAIN
BAND. POTENTIAL IS THERE FOR FRONTAL CONVECTION/QLCS TO MAINTAIN
SOME LEVEL OF INTENSITY AS IT CROSSES CENTRAL PA HOWEVER THE
BETTER MSTR/INSTABILITY WILL LKLY BE FURTHER SOUTH ACRS THE SRN
MID-ATLC. THE SPC D3 OUTLOOK PLACES THE SEE TEXT LABEL JUST SOUTH
OF THE CWA AND WILL NEED TO MONITOR PSBL DUEL HVY RAFL/LCL SVR
HAZARD IN THE COMING DAYS.
THE COLD FRONT SHOULD CLEAR THE EAST COAST FRI NGT. A COOLER
CYCLONIC FLOW PATTERN WILL SET-UP OVER THE AREA INTO THE FIRST
PART OF THE WEEKEND...WITH PERHAPS A FEW COLD-AIR RAIN/SNOW
SHOWERS IN THE FAVORED UPSLOPE AREAS. THE UPPER TROUGH QUICKLY
LIFTS OUT ON SUNDAY ALLOWING FOR MODERATING TEMPS VIA SWLY FLOW
AHEAD OF LOW PRES CROSSING THE WRN GRT LKS. MILD WX SHOULD RETURN
BY EARLY NEXT WEEK AS ANOTHER DEEP TROUGH DEVELOPS ACRS THE WRN
US.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
STATIONARY FRONT THRU NY IS EXPECTED TO SAG SLOWLY INTO NRN PA
LATER TONIGHT...POSSIBLY BRINGING SOME SHOWERS AND MVFR/IFR. THIS
BOUNDARY IS EXPECTED TO REMAIN IN THE VCNTY OF CNTRL PA THRU AT
LEAST WED WHICH WOULD SUGGEST THE BEST CHANCE FOR RAIN/THUNDER
SHOWERS AND REDUCED CONDITIONS WILL BE OVER CENTRAL AND NRN
TERMINALS.
.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...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...GARTNER/STEINBUGL
AVIATION...DANGELO/LA CORTE
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
403 PM EDT TUE APR 9 2013
.SYNOPSIS...
A WEAK FRONT WILL WAGGLE TO THE NORTH AND SOUTH OVER THE STATE
THROUGH THE NEXT FEW DAYS. THIS FRONT WILL PROVIDE A FOCUS FOR
PERIODIC OF SHOWERS AND STORMS THROUGH THURSDAY. A DYNAMIC STORM
SYSTEM CROSSING THE CENTRAL UNITED STATES WILL SEND A STRONG COLD
FRONT ACROSS THE REGION ON FRIDAY ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES WILL
BRIEFLY COOL DOWN BEHIND THE FRONT INTO THE UPCOMING WEEKEND
BEFORE REBOUNDING ABOVE NORMALS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CUMULUS CONGESTUS OVER WRN PA AT 3 PM...BUT NOTHING BREAKING
THROUGH THE CAP. LATEST RUC/RAP AND HRRR DO CONTINUE TO POINT
TOWARD SOME CONVECTION DEVELOPING THIS AFTN/EVENING IN THE SW AND
SLIDING EAST. HOWEVER...AIR IS DRY N OF RTE 22...ESP NE OF AOO.
FRONT WILL WAGGLE A BIT FARTHER N THIS EVENING...AND BEST THERMAL
GRADIENT WILL BE TO THE NORTH OF THE AREA TONIGHT. WILL STILL GIVE
A HIGH CHC/LIKELY POP TO THE NRN THIRD OF THE AREA...BUT TAPER IT
OFF TO NIL AROUND THE TURNPIKE. UNCERTAINTY IN THE CONVECTIVE
DEVELOPMENT WITH VERY WEAK FORCING IS THE BIGGEST FACTOR FOR A
WIDE RANGE IN POPS...AND CONTINUE LOW CHC POPS IN THE SRN HALF OF
THE AREA. CONFIDENCE IS HIGHEST IN THE N. WILL ALSO MENTION T FOR
THE N WHERE MSTR/DEWPOINTS DO POOL UP AND WILL BE CLOSER TO THE
DYNAMICS/FORCING. MINS WILL BE WILDLY MILD WITH SUCH A WARM START
TO THE NIGHT. CLEARING MOST LIKELY IN THE S/DOWNSLOPE AREAS TO SE
OF IPT/UNV/AOO. BUT LOWER CLOUDS SHOULD MAKE THEIR WAY DOWN TO
THAT LINE LATER TONIGHT AS THE CONVECTION/RAIN TO THE NORTH SHOVES
COOLER AIR SOUTHWARD UNDER THE VERY STRONG INVERSION.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AGAIN...THE PATHWAY FOR THE CONVECTION POSSIBLE ON WED AND
WED NIGHT WILL BE ACROSS THE NORTH. BUT...CANNOT RULE OUT THE STRAY
SHOWER OR TWO IN THE SOUTH. TIMING OF ANY FEATURES WHICH WILL
PROVIDE COHERENT FORCING REMAINS LOW AND MOST LIKELY TIED TO DEAD
UPSTREAM CONVECTION. THUS...POPS ARE BROADBRUSHED FOR MUCH OF THIS
SHORT TERM PD. TEMPS ARE HIGHLY DEPENDENT ON THE CLOUD COVER AND
HOW MUCH MIXING CAN OCCUR ON WED. WILL COUNT ON GOOD MIXING TO THE
SOUTH OF I-80 TO ALLOW TEMPS TO GET BACK TO WHERE THEY ARE THIS
AFTN...OR EVEN SLIGHTLY HIGHER. BUT TEMPS WILL PROBABLY BE A FEW
DEGS COOLER IN THE W AND N. MINS AGAIN WED NIGHT WILL BE VERY
MILD. BUT MORE COOL AIR WILL LIKELY WORK SOUTHWARD INTO THE NRN
MTS AND TAKE THE TEMPS WELL DOWN INTO THE 40S. BUT STILL SLIGHTLY
ABV NORMS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AMPLIFIED UPPER-LEVEL TROUGH WILL BE ON THE MOVE OVER THE CENTRAL
CONUS...CONSISTING OF TWO PROMINENT SHORTWAVE IMPULSES. THE
DYNAMIC SYSTEM WILL TAKE ON A NEGATIVE TILT AS IT CROSSES THE MS
RVR WITH THE BASAL IMPULSE ACCELERATING E/NEWD FROM SRN TX TOWARDS
THE CENTRAL APPALACHIANS. THE EVOLVING FRONTAL SYSTEM WILL
FEATURE AN OCCLUDING CYCLONE OVER THE GRT LKS WITH SECONDARY
TRIPLE PT LOW DEVELOPMENT IN THE UPPER OH VLY. MODEL DATA
INDICATES A SQUALL LINE/BAND OF MOD-HVY RAFL WILL ACCOMPANY THE
TRAILING COLD FRONT WHICH SHOULD BE APPROACHING/CROSSING THE WRN
PA MTNS BY 12Z FRIDAY. THE GFS IS ABOUT 6HRS FASTER THAN THE EC
AND CANADIAN WITH THE EWD PROGRESSION OF THE COLD FRONTAL RAIN
BAND. POTENTIAL IS THERE FOR FRONTAL CONVECTION/QLCS TO MAINTAIN
SOME LEVEL OF INTENSITY AS IT CROSSES CENTRAL PA HOWEVER THE
BETTER MSTR/INSTABILITY WILL LKLY BE FURTHER SOUTH ACRS THE SRN
MID-ATLC. THE SPC D3 OUTLOOK PLACES THE SEE TEXT LABEL JUST SOUTH
OF THE CWA AND WILL NEED TO MONITOR PSBL DUEL HVY RAFL/LCL SVR
HAZARD IN THE COMING DAYS.
THE COLD FRONT SHOULD CLEAR THE EAST COAST FRI NGT. A COOLER
CYCLONIC FLOW PATTERN WILL SET-UP OVER THE AREA INTO THE FIRST
PART OF THE WEEKEND...WITH PERHAPS A FEW COLD-AIR RAIN/SNOW
SHOWERS IN THE FAVORED UPSLOPE AREAS. THE UPPER TROUGH QUICKLY
LIFTS OUT ON SUNDAY ALLOWING FOR MODERATING TEMPS VIA SWLY FLOW
AHEAD OF LOW PRES CROSSING THE WRN GRT LKS. MILD WX SHOULD RETURN
BY EARLY NEXT WEEK AS ANOTHER DEEP TROUGH DEVELOPS ACRS THE WRN
US.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
CU BUILDING ALONG AND JUST BEHIND THE WARM FRONT. BRIEF/ISOLD SHRA
ARE POSS WITH JUST AN OUTSIDE CHC OF THUNDER AS A SMALL AMT OF
CAPE EXPECTED IN THE WEST. WILL NOT MENTION T IN TAFS AT THIS
POINT DUE TO EXTREMELY LOW CHC. WIND WILL STAY 10-15KTS THROUGH
MOST OF THE EVENING. MCV/REMNANTS MOVING ACROSS LAKE ERIE/LWR ONT.
A WEAK TAIL OF VORT IS DRAPED SWRD AND COULD MEET UP WITH THE BEST
CAPE TO GENERATE SOME SHRA/TSRA IN BFD BEFORE 00Z. OTHERWISE...THE
NEXT WAVE OF LIFT COMES ALONG LATER THIS EVENING/TONIGHT. WILL
HOLD MENTIONS OF SHRA IN MOST TAFS FOR AT LEAST THE FIRST PART OF
THE NIGHT. WIND ALOFT GETS PRETTY STRONG AND LOWERS AS THE LL JET
SLINGS BY. THE STRONG WINDS GET DOWN TO FL010/015 IN THE MIDDLE OF
NIGHT...BUT SLACKEN SIGNIFICANTLY AFTER 09Z. WILL THEN NOT MENTION
LLWS AFTERWARD. SCT/NWRS SHRA ACROSS THE N WED AFTN/NIGHT. BUT
LESS OF A CHC OVER MOST TERMINALS WITH BEST MSTR POOLING AND
THERMAL GRADIENT WELL TO THE NORTH OF UNV/IPT. WILL MENTION MVFR
CIGS IN THE MORNING FOR IPT/UNV...BUT ALLOW FOR SOME MIXING TO
RAISE THE CIGS IN THE AFTN WED. WAVES OF LOW PRESSURE THEN
CONTINUE TO MOVE W-E ALONG THE WAVY FRONT WED NIGHT AND THURSDAY
IN ADVANCE OF SYSTEM WHICH WILL WRAP UP OVER THE MIDWEST/OH VALLEY
AND MOVE THROUGH LATE THURS/EARLY FRI.
.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...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...GARTNER/STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
309 PM EDT TUE APR 9 2013
.SYNOPSIS...
A WEAK FRONT WILL WAGGLE TO THE NORTH AND SOUTH OVER THE STATE
THROUGH THE NEXT FEW DAYS. THIS FRONT WILL PROVIDE A FOCUS FOR
PERIODIC OF SHOWERS AND STORMS THROUGH THURSDAY. A DYNAMIC STORM
SYSTEM CROSSING THE CENTRAL UNITED STATES WILL SEND A STRONG COLD
FRONT ACROSS THE REGION ON FRIDAY ACCOMPANIED BY WIDESPREAD
SHOWERS AND THUNDERSTORMS. UNSEASONABLY WARM TEMPERATURES WILL
BRIEFLY COOL DOWN BEHIND THE FRONT INTO THE UPCOMING WEEKEND
BEFORE REBOUNDING ABOVE NORMALS EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CUMULUS CONGESTUS OVER WRN PA AT 3 PM...BUT NOTHING BREAKING
THROUGH THE CAP. LATEST RUC/RAP AND HRRR DO CONTINUE TO POINT
TOWARD SOME CONVECTION DEVELOPING THIS AFTN/EVENING IN THE SW AND
SLIDING EAST. HOWEVER...AIR IS DRY N OF RTE 22...ESP NE OF AOO.
FRONT WILL WAGGLE A BIT FARTHER N THIS EVENING...AND BEST THERMAL
GRADIENT WILL BE TO THE NORTH OF THE AREA TONIGHT. WILL STILL GIVE
A HIGH CHC/LIKELY POP TO THE NRN THIRD OF THE AREA...BUT TAPER IT
OFF TO NIL AROUND THE TURNPIKE. UNCERTAINTY IN THE CONVECTIVE
DEVELOPMENT WITH VERY WEAK FORCING IS THE BIGGEST FACTOR FOR A
WIDE RANGE IN POPS...AND CONTINUE LOW CHC POPS IN THE SRN HALF OF
THE AREA. CONFIDENCE IS HIGHEST IN THE N. WILL ALSO MENTION T FOR
THE N WHERE MSTR/DEWPOINTS DO POOL UP AND WILL BE CLOSER TO THE
DYNAMICS/FORCING. MINS WILL BE WILDLY MILD WITH SUCH A WARM START
TO THE NIGHT. CLEARING MOST LIKELY IN THE S/DOWNSLOPE AREAS TO SE
OF IPT/UNV/AOO. BUT LOWER CLOUDS SHOULD MAKE THEIR WAY DOWN TO
THAT LINE LATER TONIGHT AS THE CONVECTION/RAIN TO THE NORTH SHOVES
COOLER AIR SOUTHWARD UNDER THE VERY STRONG INVERSION.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AGAIN...THE PATHWAY FOR THE CONVECTION POSSIBLE ON WED AND
WEDNIGHT WILL BE ACROSS THE NORTH. BUT...CANNOT RULE OUT THE STRAY
SHOWER OR TWO IN THE SOUTH. TIMING OF ANY FEATURES WHICH WILL
PROVIDE COHERENT FORCING REMAINS LOW AND MOST LIKELY TIED TO DEAD
UPSTREAM CONVECTION. THUS...POPS ARE BROADBRUSHED FOR MUCH OF THIS
SHORT TERM PD. TEMPS ARE HIGHLY DEPENDENT ON THE CLOUD COVER AND
HOW MUCH MIXING CAN OCCUR ON WED. WILL COUNT ON GOOD MIXING TO THE
SOUTH OF I-80 TO ALLOW TEMPS TO GET BACK TO WHERE THEY ARE THIS
AFTN...OR EVEN SLIGHTLY HIGHER. BUT TEMPS WILL PROBABLY BE A FEW
DEGS COOLER IN THE W AND N. MINS AGAIN WED NIGHT WILL BE VERY
MILD. BUT MORE COOL AIR WILL LIKELY WORK SOUTHWARD INTO THE NRN
MTS AND TAKE THE TEMPS WELL DOWN INTO THE 40S. BUT STILL SLIGHTLY
ABV NORMS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
AMPLIFIED UPPER-LEVEL TROUGH WILL BE ON THE MOVE OVER THE CENTRAL
CONUS...CONSISTING OF TWO PROMINENT SHORTWAVE IMPULSES. THE
DYNAMIC SYSTEM WILL TAKE ON A NEGATIVE TILT AS IT CROSSES THE MS
RVR WITH THE BASAL IMPULSE ACCELERATING E/NEWD FROM SRN TX TOWARDS
THE CENTRAL APPALACHIANS. THE EVOLVING FRONTAL SYSTEM WILL
FEATURE AN OCCLUDING CYCLONE OVER THE GRT LKS WITH SECONDARY
TRIPLE PT LOW DEVELOPMENT IN THE UPPER OH VLY. MODEL DATA
INDICATES A SQUALL LINE/BAND OF MOD-HVY RAFL WILL ACCOMPANY THE
TRAILING COLD FRONT WHICH SHOULD BE APPROACHING/CROSSING THE WRN
PA MTNS BY 12Z FRIDAY. THE GFS IS ABOUT 6HRS FASTER THAN THE EC
AND CANADIAN WITH THE EWD PROGRESSION OF THE COLD FRONTAL RAIN
BAND. POTENTIAL IS THERE FOR FRONTAL CONVECTION/QLCS TO MAINTAIN
SOME LEVEL OF INTENSITY AS IT CROSSES CENTRAL PA HOWEVER THE
BETTER MSTR/INSTABILITY WILL LKLY BE FURTHER SOUTH ACRS THE SRN
MID-ATLC. THE SPC D3 OUTLOOK PLACES THE SEE TEXT LABEL JUST SOUTH
OF THE CWA AND WILL NEED TO MONITOR PSBL DUEL HVY RAFL/LCL SVR
HAZARD IN THE COMING DAYS.
THE COLD FRONT SHOULD CLEAR THE EAST COAST FRI NGT. A COOLER
CYCLONIC FLOW PATTERN WILL SET-UP OVER THE AREA INTO THE FIRST
PART OF THE WEEKEND...WITH PERHAPS A FEW COLD-AIR RAIN/SNOW
SHOWERS IN THE FAVORED UPSLOPE AREAS. THE UPPER TROUGH QUICKLY
LIFTS OUT ON SUNDAY ALLOWING FOR MODERATING TEMPS VIA SWLY FLOW
AHEAD OF LOW PRES CROSSING THE WRN GRT LKS. MILD WX SHOULD RETURN
BY EARLY NEXT WEEK AS ANOTHER DEEP TROUGH DEVELOPS ACRS THE WRN
US.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
CU BUILDING ALONG AND JUST BEHIND THE WARM FRONT. BRIEF/ISOLD SHRA
ARE POSS WITH JUST AN OUTSIDE CHC OF THUNDER AS A SMALL AMT OF
CAPE EXPECTED IN THE WEST. WILL NOT MENTION T IN TAFS AT THIS
POINT DUE TO EXTREMELY LOW CHC. WIND WILL STAY 10-15KTS THROUGH
MOST OF THE EVENING. MCV/REMNANTS MOVING ACROSS LAKE ERIE/LWR ONT.
A WEAK TAIL OF VORT IS DRAPED SWRD AND COULD MEET UP WITH THE BEST
CAPE TO GENERATE SOME SHRA/TSRA IN BFD BEFORE 00Z. OTHERWISE...THE
NEXT WAVE OF LIFT COMES ALONG LATER THIS EVENING/TONIGHT. WILL
HOLD MENTIONS OF SHRA IN MOST TAFS FOR AT LEAST THE FIRST PART OF
THE NIGHT. WIND ALOFT GETS PRETTY STRONG AND LOWERS AS THE LL JET
SLINGS BY. THE STRONG WINDS GET DOWN TO FL010/015 IN THE MIDDLE OF
NIGHT...BUT SLACKEN SIGNIFICANTLY AFTER 09Z. WILL THEN NOT MENTION
LLWS AFTERWARD. SCT/NWRS SHRA ACROSS THE N WED AFTN/NIGHT. BUT
LESS OF A CHC OVER MOST TERMINALS WITH BEST MSTR POOLING AND
THERMAL GRADIENT WELL TO THE NORTH OF UNV/IPT. WILL MENTION MVFR
CIGS IN THE MORNING FOR IPT/UNV...BUT ALLOW FOR SOME MIXING TO
RAISE THE CIGS IN THE AFTN WED. WAVES OF LOW PRESSURE THEN
CONTINUE TO MOVE W-E ALONG THE WAVY FRONT WED NIGHT AND THURSDAY
IN ADVANCE OF SYSTEM WHICH WILL WRAP UP OVER THE MIDWEST/OH VALLEY
AND MOVE THROUGH LATE THURS/EARLY FRI.
.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...DANGELO
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...DANGELO
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
834 PM CDT WED APR 10 2013
.UPDATE...
EVENING FORECAST UPDATE.
&&
.DISCUSSION...
COLD FRONT HAS PUSHED INTO THE UPPER TX COASTAL WATERS THIS
EVENING BUT HAS NOT MADE A WHOLE LOT OF PROGRESS. FRONT HAS SLOWED
WITH IT BECOMING MORE NNE/SSW ORIENTED. STARTING TO GET SOME
ELEVATED SHOWERS OVER THE FRONT MAINLY EAST OF A CONROE...KATY TO
BAY CITY LINE. WATER VAPOR IMAGERY SHOWS STORTWAVE TROUGH AND JET
STREAK COMING THROUGH MEX INTO THE RIO GRANDE VALLEY/S TX. THIS
MAY ENHANCE ELEVATED CONVECTION OVER SE TX DURING THE EARLY
MORNING HOURS. OVERALL THINK MODELS ARE ON TRACK BUT THAT
GFS/ECMWF ARE OVER DOING PRECIP AMOUNTS AND COVERAGE. THINK THERE
WILL BE SCATTERED ACTIVITY BUT PRECIP AMOUNTS WILL DEPEND ON
REDEVELOPMENT OF CELLS AND TRAINING. DECIDED TO KEEP POPS AROUND
50 PERCENT BUT COULD SEE ADJUSTMENT FOR HIGHER POPS. THE HRRR HAS
BEEN DOING FAIRLY WELL WITH ITS CONVECTIVE TRENDS SO FAR AND THINK
WITH IT DEVELOPING CONVECTION AFTER 07Z TONIGHT...COASTAL AREAS
COULD SEE SOME DECENT RAIN. WILL CONTINUE TO MONITOR TRENDS IN
CONVECTION BUT MAY NEED TO WATCH FOR HOW MUCH CONVECTION FORMS
AFTER MIDNIGHT WITH THE APPROACHING SHORTWAVE.
39
&&
.PREV DISCUSSION... /ISSUED 640 PM CDT WED APR 10 2013/
DISCUSSION...
SEE AVIATION FOR 00Z TAF ISSUANCE
AVIATION...
SURFACE FRONT HAS PUSHED THROUGH ALL SOUTHEAST TEXAS TERMINALS
THIS EVENING. WIND GUSTS ARE PICKING UP ACROSS THE NORTHERN HALF
OF THE REGION AS THE UPPER LEVEL FRONT ARRIVES AND THESE SHOULD
CONTINUE TO OVERSPREAD THE REST OF THE REGION WITHIN THE NEXT HOUR
OR SO.
MAIN CONCERN THIS EVENING REMAINS EXTENT OF IFR CIGS AND POTENTIAL
OVERNIGHT SHRA ACTIVITY. SEVERAL OF THE MODELS REDEVELOP
PRECIPITATION BEHIND THE FRONT ACROSS AREAS ALONG AND SOUTH OF
INTERSTATE 10 AND EAST OF US 59...AFFECTING ALL SITES EXCEPT CLL.
WILL KEEP MENTION OF VCSH THROUGH 09Z FOR SOUTHERN SITES BUT AM
EXPECTING ACTIVITY TO WANE OR PUSH EAST OF THE REGION BY THEN. ONE
MODEL DOES SUPPORT SOME STRONGER SHRA OR PERHAPS ISOLATED TSRA
AROUND 09Z DUE TO STRONG UPPER LEVEL DIFFLUENCE BUT AM NOT
CONFIDENT IN THIS SOLUTION AND WILL KEEP MENTION OF TSRA OUT OF
THE TAFS FOR NOW. AS PCPN BEGINS TO END EXPECT IFR CIGS TO BEGIN
IMPROVING...FIRST AT CLL AND THEN ACROSS THE REST OF THE REGION
BETWEEN 09-12Z THURSDAY. AM EXPECTING SCT250 OR SKC BY
MIDAFTERNOON THURSDAY WITH WINDS BECOMING NORTHEAST AFTER 11/00Z
AS BROAD SURFACE HIGH PRESSURE SHIFTS INTO THE MISSISSIPPI RIVER
VALLEY. 38
PREV DISCUSSION... /ISSUED 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 / 50 20 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
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.
&&
$$
DISCUSSION...39
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
640 PM CDT WED APR 10 2013
.DISCUSSION...
SEE AVIATION FOR 00Z TAF ISSUANCE
&&
.AVIATION...
SURFACE FRONT HAS PUSHED THROUGH ALL SOUTHEAST TEXAS TERMINALS
THIS EVENING. WIND GUSTS ARE PICKING UP ACROSS THE NORTHERN HALF
OF THE REGION AS THE UPPER LEVEL FRONT ARRIVES AND THESE SHOULD
CONTINUE TO OVERSPREAD THE REST OF THE REGION WITHIN THE NEXT HOUR
OR SO.
MAIN CONCERN THIS EVENING REMAINS EXTENT OF IFR CIGS AND POTENTIAL
OVERNIGHT SHRA ACTIVITY. SEVERAL OF THE MODELS REDEVELOP
PRECIPITATION BEHIND THE FRONT ACROSS AREAS ALONG AND SOUTH OF
INTERSTATE 10 AND EAST OF US 59...AFFECTING ALL SITES EXCEPT CLL.
WILL KEEP MENTION OF VCSH THROUGH 09Z FOR SOUTHERN SITES BUT AM
EXPECTING ACTIVITY TO WANE OR PUSH EAST OF THE REGION BY THEN. ONE
MODEL DOES SUPPORT SOME STRONGER SHRA OR PERHAPS ISOLATED TSRA
AROUND 09Z DUE TO STRONG UPPER LEVEL DIFFLUENCE BUT AM NOT
CONFIDENT IN THIS SOLUTION AND WILL KEEP MENTION OF TSRA OUT OF
THE TAFS FOR NOW. AS PCPN BEGINS TO END EXPECT IFR CIGS TO BEGIN
IMPROVING...FIRST AT CLL AND THEN ACROSS THE REST OF THE REGION
BETWEEN 09-12Z THURSDAY. AM EXPECTING SCT250 OR SKC BY
MIDAFTERNOON THURSDAY WITH WINDS BECOMING NORTHEAST AFTER 11/00Z
AS BROAD SURFACE HIGH PRESSURE SHIFTS INTO THE MISSISSIPPI RIVER
VALLEY. 38
&&
.PREV DISCUSSION... /ISSUED 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...NONE.
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.
&&
$$
DISCUSSION...39
AVIATION/MARINE...38
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
104 PM CDT TUE APR 9 2013
.UPDATE...
THE 18Z FWD SOUNDING THAT WAS LAUNCHED HAS DATA QUALITY PROBLEMS
AND SHOULD BE DISREGARDED FOR THE MOST PART. THE CAP IS STILL IN
PLACE ACROSS THE REGION AND WE WILL INSTEAD BE USING ACARS
SOUNDINGS FOR DATA THROUGH THE AFTERNOON HOURS. THE INSTRUMENT
THAT WAS USED FOR THE 18Z FWD SOUNDING IS A TEST INSTRUMENT AND
THIS WAS THE FIRST UPPER AIR LAUNCH WITH THIS NEW RADIOSONDE.
82/JLD
&&
.AVIATION...
PERSISTENCE WILL BE THE KEY REGARDING SURFACE WINDS TODAY AS
STRONG LOW LEVEL FLOW CONTINUES AHEAD OF THE STORM SYSTEM
CURRENTLY OVER THE 4-CORNERS REGION. WILL MAINTAIN THE FORECAST OF
SUSTAINED WINDS IN THE 15-20KT RANGE UP UNTIL THE PASSAGE OF THE
FRONT TONIGHT. MEANWHILE...STRATUS WITHIN THE 50+ KT LOW LEVEL JET
CONTINUES TO STREAM OVERHEAD. BREAKS IN THE CLOUD FIELD CAN BE
SEEN ON 11-3.9 MICRON IMAGERY SO CIGS WILL LIKELY VARY BETWEEN VFR
AND MVFR AT ALL SITES THIS MORNING.
FOR TONIGHT...A STRONG COLD FRONT PROJECTED TO ADVANCE
SOUTHEASTWARD ACROSS NORTH TEXAS WILL LIKELY BE ACCOMPANIED BY
A ROUND OF SHOWERS AND STORMS. A BLEND OF THE LATEST MODEL GUIDANCE
INDICATES FROPA IN THE METROPLEX 08-09Z AND CLOSER TO 12Z AT KACT.
STRONG NORTH-NORTHWESTERLY WINDS WILL OCCUR WEDNESDAY FOLLOWING
THE PASSAGE OF THE FRONT...WITH MVFR CONDITIONS LINGERING THROUGH
MUCH OF THE DAY.
30
&&
.PREV UPDATE...
.UPDATE...
AT 11 AM THIS MORNING...A LARGE UPPER LEVEL LOW WAS MOVING
ACROSS NORTHERN NEW MEXICO WITH THE BASE OF THE UPPER LEVEL TROUGH
SWINGING DOWN INTO EXTREME NORTHERN MEXICO. AT THE SURFACE...A
COLD FRONT WAS MOVING AHEAD OF SCHEDULE THROUGH THE TEXAS
PANHANDLE WITH A DRYLINE EXTENDING DOWN THROUGH FAR WEST TEXAS.
THE COLD FRONT WAS LOCATED JUST NORTH OF PLAINVIEW TEXAS EXTENDING
BACK TO THE NORTHEAST TO WOODWARD OKLAHOMA AND MEDICINE LODGE
KANSAS. TEMPERATURES BEHIND THE FRONT ARE IN THE 30S WITH WINDS
GUSTING AROUND 40 MPH AT SEVERAL LOCATIONS. THESE CONDITIONS ARE
QUICKLY ACCELERATING THE FRONT FASTER THAN PREVIOUSLY THOUGHT BUT
THE 12Z NAM AND RAP HAVE PICKED UP ON THE FASTER FRONTAL LOCATION.
UNFORTUNATELY THE 12Z GFS IS STILL MUCH TOO SLOW AND HAD TO BE
DISCOUNTED FOR MUCH OF THE UPDATE.
BY MID AFTERNOON THE DRYLINE WILL BE LOCATED ALONG THE WESTERN
BORDER OF THE CWA WITH THE COLD FRONT ALREADY MOVING ACROSS
SOUTHWESTERN OKLAHOMA AND NORTHWEST TEXAS. THE COLD FRONT WILL
QUICKLY OVERTAKE THE DRYLINE BY THE LATE AFTERNOON/EARLY EVENING
HOURS JUST NORTHWEST OF THE AREA AND WILL START TO ENTER OUR
NORTHWESTERN COUNTIES BY 10 PM. WITH THIS FASTER TIMING...THIS
FURTHER LIMITS THE POTENTIAL FOR STORMS TO DEVELOP ON THE DRYLINE
THIS AFTERNOON. HAVE UPDATED ALL APPROPRIATE FORECAST PARAMETERS
THROUGH TOMORROW TO REFLECT THE LOCATION OF THE DRYLINE AND THE
FASTER FRONTAL ARRIVAL AND MOVEMENT.
REGARDING THE SEVERE WEATHER POTENTIAL FOR LATER TODAY AND
TONIGHT. UNCERTAINTY STILL REMAINS ON IF STORMS WILL DEVELOP ON
THE DRYLINE NEAR OUR WESTERN AND/OR NORTHWESTERN COUNTIES. THE 12Z
FWD SOUNDING THIS MORNING SHOWS A VERY LARGE CAP STILL IN PLACE
AND MODIFYING THE SOUNDING FOR AFTERNOON TEMPERATURES IN THE MID
80S STILL REVEALS A STRONG CAP OVER -100 J/KG. WE WILL BE DOING A
SPECIAL 18Z SOUNDING THIS AFTERNOON AND WILL SEE HOW THE CAP HAS
CHANGED SINCE 12Z THIS MORNING. WE CONTINUE TO MAINTAIN THE
THINKING THAT THE CAP WILL HOLD OVER THE AREA THIS AFTERNOON BUT
WE DO NOT DISCOUNT THAT THERE IS A NARROW WINDOW AROUND 5-7 PM
DURING WHICH THE CAP COULD BE BREACHED BEFORE THE FRONT TAKES OVER
THE DRYLINE. HOWEVER...WITH THE MAIN UPPER LEVEL LIFT STILL WEST
OF THE REGION AT THAT TIME...IT WILL LIKELY BE VERY DIFFICULT TO
DEVELOP ANY STORMS ALONG THE DRYLINE. BUT ANY STORM THAT IS ABLE
TO DEVELOP ON THE DRYLINE WOULD HAVE A THREAT FOR LARGE
HAIL...DAMAGING WINDS...AND POSSIBLY A TORNADO. THESE STORMS WOULD
BE MOVING TO THE NORTHEAST AND WOULD LIKELY ONLY POSE A THREAT TO
A FEW OF OUR NORTHWESTERN COUNTIES FROM STEPHENS TO MONTAGUE
COUNTY.
AS THE COLD FRONT MOVES THROUGH THE REGION OVERNIGHT...A LINE OF
STORMS WILL LIKELY OCCUR ALONG THE LEADING EDGE WITH A THREAT FOR
SCATTERED SEVERE STORMS ALONG THE LINE...MAINLY FROM 10 PM THROUGH
6 AM. IN ADDITION...CONVECTION WILL LIKELY ALSO BE OCCURRING BEHIND
THE LEADING EDGE OF THE FRONT AND SOUNDINGS STILL SUPPORT THE
POTENTIAL FOR HAIL WITH THESE STORMS IF THEY CAN REACH THROUGH THE
REDEVELOPING CAP OVERNIGHT.
82/JLD
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT TUE APR 9 2013/
ANOTHER MOSTLY CLOUDY...BREEZY AND WARM DAY IS IN STORE FOR NORTH
TEXAS TODAY AHEAD OF AN APPROACHING UPPER LEVEL STORM SYSTEM AND
ASSOCIATED COLD FRONT. AS OF 3 AM THE COLD FRONT HAD ALREADY MOVED
INTO SOUTHEAST COLORADO AND NORTHWEST KANSAS WITH WIND GUSTS
BEHIND THE FRONT AS HIGH AS 58 MPH. THE AIR BEHIND THE FRONT IS
VERY COLD FOR EARLY APRIL WITH TEENS AND 20S ACROSS PARTS OF
WYOMING AND NEBRASKA. THE COLD FRONT WILL CONTINUE TO SURGE SOUTH
TODAY BUT SHOULD SLOW A BIT DUE TO BOUNDARY LAYER MIXING ON THE
LEADING EDGE. THE DRY LINE WILL ALSO MIX EASTWARD THROUGH THE DAY
AND SHOULD APPROACH THE EXTREME WESTERN ZONES BEFORE SUNSET. THE
COLD FRONT SHOULD OVERTAKE THE DRYLINE DURING EVENING AND MOVE
QUICKLY ACROSS NORTH TEXAS OVERNIGHT/WEDNESDAY MORNING.
THE MOST LIKELY SCENARIO WHERE THUNDERSTORMS ARE CONCERNED IS
THAT THE STRONG CAP THAT IS CURRENTLY IN PLACE ACROSS THE REGION
WILL WEAKEN THROUGH THE DAY AS LARGE SCALE LIFT INCREASES. THE CAP
MAY BREAK IN THE EXTREME NORTHWEST ZONES JUST BEFORE SUNSET WITH
RAPID THUNDERSTORM DEVELOPMENT POSSIBLE. HOWEVER...CONFIDENCE IS
LOW THAT THE CAP WILL BREAK BEFORE THE COLD FRONT ARRIVES THIS
EVENING...AND THIS IS SUPPORTED BY THE 4 KM WRF AND TTU WRF.
THEREFORE...WILL LEAVE ONLY LOW LATE AFTERNOON POPS IN THE EXTREME
NORTHWEST ZONES ON THE OUTSIDE CHANCE THAT THE CAP BREAKS. IF ANY
STORMS DO DEVELOP BEFORE SUNSET...THEY WILL HAVE SUFFICIENT
INSTABILITY AND SHEAR TO SUPPORT SUPERCELL FORMATION.
THE CAP SHOULD BREAK BY LATE EVENING AS THE COLD FRONT BEGINS TO
MOVE THROUGH THE REGION. STORMS THAT DEVELOP ALONG OR JUST AHEAD
OF THE COLD FRONT WILL HAVE A GOOD CHANCE OF BECOMING SEVERE WITH
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CAN NOT BE
RULED OUT BUT FEEL THE TIME OF DAY AND SPEED OF THE FRONT MAY
LIMIT THE POTENTIAL. THE HIGH RES MODELS CONTINUE TO SHOW THE
FRONT MOVING QUICKLY THROUGH THE REGION WITH POST-FRONTAL...MAINLY
NON SEVERE...THUNDERSTORMS OVERNIGHT/WEDNESDAY MORNING. THE GOOD
NEWS IS THAT THE WINDOW SEVERE WEATHER IN ANY ONE AREA SHOULD BE SMALL
WITH A MUCH LARGER WINDOW OF TIME FOR MUCH NEEDED POST-FRONTAL
PRECIPITATION. ALL SHOWERS AND STORMS SHOULD END FROM WEST TO EAST
ON WEDNESDAY AS MUCH DRIER AND COLDER AIR MOVES IN.
THE NEXT CHALLENGE WITH THIS FORECAST WILL BE THE POST-FRONTAL
TEMPERATURES. THE NAM CONTINUES TO BE THE COLDEST OF THE SOLUTIONS
AND BASED ON LATEST SURFACE ANALYSIS...IT SEEMS TO HAVE THE BEST
HANDLE ON THE COLD AIR. EXPECT AFTERNOON HIGHS WEDNESDAY TO ONLY
REACH THE LOWER 50S IN THE NORTHWEST ZONES BUT THE SOUTHEAST SHOULD
STILL BE IN THE UPPER 60S TO LOWER 70S. CLEARING SKIES AND
DECREASING WIND SPEEDS WEDNESDAY NIGHT WILL ALLOW TEMPS TO FALL
INTO THE 30S TO LOWER 40S. IT APPEARS THAT ONLY THE NORTHWEST
ZONES WILL APPROACH FREEZING BRIEFLY AROUND SUNRISE THURSDAY
MORNING. TEMPERATURES WILL BEGIN TO REBOUND ON THURSDAY AFTERNOON AS
SURFACE HIGH PRESSURE MOVES TO THE EAST. THE WARMING TREND WILL
CONTINUE THROUGH THE WEEKEND AS LOW LEVEL MOISTURE RETURNS TO THE
REGION. WEST TO SOUTHWEST FLOW ALOFT AND A PERSISTENT LEE TROUGH
WILL KEEP WARM AND RAIN-FREE WEATHER ACROSS NORTH TEXAS THROUGH
EARLY NEXT WEEK.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 50 57 38 62 41 / 90 60 10 0 0
WACO, TX 60 62 39 64 41 / 90 70 10 5 0
PARIS, TX 60 62 37 57 39 / 90 70 20 5 0
DENTON, TX 47 55 35 61 36 / 90 60 10 0 0
MCKINNEY, TX 52 58 35 59 38 / 90 60 10 5 0
DALLAS, TX 53 59 39 61 42 / 90 70 10 0 0
TERRELL, TX 59 61 35 60 40 / 90 70 10 5 0
CORSICANA, TX 63 65 35 64 41 / 70 80 10 5 0
TEMPLE, TX 63 64 39 64 42 / 80 80 10 5 0
MINERAL WELLS, TX 42 51 33 63 38 / 90 40 10 0 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/82
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
100 PM CDT TUE APR 9 2013
.UPDATE...
ANOTHER UPDATE AS THE COLD FRONT CONTINUES PROGRESSING TO THE
SOUTH WELL AHEAD OF SCHEDULE. NOT MUCH INDICATION YET OF SLOWING
ALTHOUGH THE LATEST RAP CONTINUES TO HOLD FRONT FROM PASSING
THROUGH ALL OF THE SOUTHWESTERN COUNTIES. WE WILL SEE AND UPDATE
AGAIN AS NEEDED. ADDED PATCHY BLOWING DUST THIS TIME...EXPECT TO
SEE VISIBILITY BRIEFLY DROP AS LOW AS ONE TO THREE MILES JUST
BEHIND THE FRONT THEN GRADUALLY IMPROVING. WE ALSO INCREASED THE
MENTION OF THUNDER INTO THE CHANCE CATEGORY OVER TE NORTHERN
ROLLING PLAINS...THOUGH VEERED LOW LEVEL WINDS SHOULD ALLOW
MOISTURE TO CLEAR OUT ENOUGH TO THE EAST TO KEEP SEVERE RISK JUST
BELOW MENTIONABLE LEVELS. LOTS OF ISSUES TO FOLLOW TONIGHT THAT
HAVE YET TO BE FULLY RESOLVED REGARDING PRECIPITATION
CHANCES...POSSIBILITY FOR FREEZING PRECIPITATION...AND ALSO FOR A
FREEZE OVER THE NORTHERN ROLLING PLAINS. RMCQUEEN
&&
.AVIATION...
ADJUSTMENTS MADE FOR MUCH EARLIER FRONTAL PASSAGE...ADDED BLOWING
DUST AT KLBB...VICINITY SHOWERS AT KCDS EARLY AND MENTION OF
DRIZZLE AND LIGHT FOG LATER...AND ALSO LOWER CEILINGS DEVELOPING
ESPECIALLY AT KCDS. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 1004 AM CDT TUE APR 9 2013/
UPDATE...
THE COLD FRONT HAS PASSED THROUGH FRIONA...DIMMITT...AND HAPPY
ALREADY QUITE A BIT AHEAD OF SCHEDULE. SHORT TERM SURFACE PRESSURE
RISES HAVE WEAKENED BUT THE FRONT WAS CONTINUING TO ADVANCE ON
LARGER SCALE PUSHES. WE HAVE ACCEPTED THE LATEST RAP RUN FOR NOW
AND UPDATED FOR THE FRONT TO WORK THROUGH MOST OF THE NORTHERN
AREA BEFORE STALLING AROUND MIDDAY. TEMPERATURES LOWERED ACROSS
NORTHERN ZONES AND WARMED SLIGHTLY SOME SOUTHERN AREAS. THE FRONT
MAY BE ABLE TO CATCH UP TO THE MOISTURE LYING OVER THE NORTHERN
ROLLING PLAINS AND GIVE A VALID LOW CHANCE FOR THUNDER. WE WILL
STUDY FURTHER FOR SEVERE CHANCES AS WELL. RMCQUEEN
PREV DISCUSSION... /ISSUED 623 AM CDT TUE APR 9 2013/
AVIATION...
MVFR CIGS DEVELOPING IN MOIST AIR THAT HAS MOVED BACK INTO THE
FCST AREA WILL PERSIST UNTIL LOW LEVEL WINDS BEGIN TO VEER TO THE
SW AND INCREASE IN SPEED. THAT IS LIKELY TO OCCUR BY 14Z AT KLBB
AND 17Z AT KCDS. AFTERWARDS...GUSTY SW WINDS EXPECTED THROUGH THE
DAY FOLLOWED BY GUSTY NORTH WINDS BEHIND A STRONG COLD FRONT THAT
WILL MOVE THROUGH THE FCST AREA THIS EVENING. POTENTIAL FOR SOME
LIGHT SHOWERS OVERNIGHT WITH THE APPROACH OF AN UPPER LEVEL
DISTURBANCE FAVORS KCDS OVER KLBB.
PREV DISCUSSION... /ISSUED 319 AM CDT TUE APR 9 2013/
SHORT TERM...
RATHER DYNAMIC PATTERN SETTING UP FOR THE NEXT 24 HOURS AS A STRONG
UPPER LOW EJECTS FROM THE 4-CORNERS TO THE CNTL PLAINS WHILE THE
PARENT TROUGH MOVES FROM WEST TO EAST TOWARD THE FCST AREA.
INITIALLY A MID LEVEL JET WILL PUNCH ACROSS THE AREA AS IT ROTATES
NEWD WITH THE UPPER LOW. PROGGED MAGNITUDE OF THIS JET HAS WEAKENED
RELATIVE TO RECENT MODEL RUNS WITH 500 MB SPEEDS OF AROUND 90 KTS
AND 700 MB ABOUT HALF THAT. MIXING WILL BE FAIRLY EFFICIENT DESPITE
COOLER TEMPERATURES THAN THE LAST FEW DAYS COURTESY OF LOWERING
HEIGHTS AND THICKNESSES WITH THE ADVANCING UPPER TROUGH. THIS SHOULD
RESULT IN WINDS MOSTLY IN A RANGE OF 20 TO 30 MPH...PERIODICALLY
SLIGHTLY STRONGER UP ON THE CAPROCK...ATTM NOT EXPECTED TO BE QUITE
STRONG ENOUGH TO JUSTIFY A WIND ADVISORY. THIS MID LEVEL JET MAX
WILL HELP QUICKLY MIX THE DRYLINE EWD THROUGH THE FCST AREA WITH LOW
DEW POINT AIR MOVING IN BEHIND IT AND EFFECTIVELY KILLING ANY PRECIP
CHANCES DURING THE AFTN.
THAT LOOKS TO CHANGE OVERNIGHT AS THE UPPER TROUGH CONTINUES TO
ADVANCE TOWARD THE AREA. MID LEVEL LIFT AND MOISTURE ASSOCIATED WITH
THE TROUGH LIKELY SUFFICIENT TO PRODUCE SOME ELEVATED SHOWERS ACROSS
MAINLY THE NRN HALF OF THE FCST AREA WHERE THAT COMBINATION WILL BE
GREATEST. STILL DO NOT EXPECT ANYTHING MORE THAN A SCATTERED NATURE
TO THE SHOWERS AND 30 TO 40 PCT POPS THERE LOOK REASONABLE. FCST
FURTHER COMPLICATED BY A STRONG COLD FRONT THAT WILL MOVE QUICKLY
THROUGH THE FCST AREA DURING THE EVENING HOURS. THIS FRONT WILL
USHER IN VERY COLD AIR THE STRENGTH OF WHICH IS INDICATED BY
TEMPERATURES IN THE TEENS AND 20S ACROSS SERN WYOMING AND NERN
COLORADO PENETRATING SWD DOWN THE LEE OF THE FRONT RANGE. THAT FRONT
IS JUST SOUTH OF A TRINIDAD COLO TO SPRINGFIELD COLO TO COLBY KS
LINE AT 08Z. THIS IS JUST A BIT AHEAD OF WRF-NAM POSITIONING. THE
FRONT WILL MOVE INTO THE TEXAS PANHANDLE THIS MORNING WHERE IT
SHOULD STALL IN THE FACE OF WARM TEMPS AND SW WINDS...BUT THEN
QUICKLY ACCELERATE SWD LATE THIS AFTN OR EARLY THIS EVENING. COLD AIR
THAT COMES IN BEHIND THE FRONT MAY BE COLD ENOUGH TO PRODUCE SOME
FROZEN PRECIP BEFORE PRECIP COMES TO AN END TONIGHT...AND WILL
MAINTAIN THAT WORDING IN THE FCST WITH ONLY MINOR ADJUSTMENTS TO
AREAL EXTENT. PRESSURE RISES BEHIND THE FRONT LIKELY TO BE FAIRLY
STRONG WITH SOME POTENTIAL FOR WIND ADVISORY SPEEDS FOR A TIME
OVERNIGHT.
LONG TERM...
PER THE NAM...GFS AND CMC SOLUTIONS...THE MEAN TROUGH OF THE BROAD UA
LOW ACROSS THE CENTRAL PLAINS WILL CONTINUE TO SWING EAST ACROSS THE
ROLLING PLAINS TOMORROW MORNING...WHILST THE BEST PRECIP WILL
SHIFT EAST OF THE CWA THUS COINCIDING WITH BEST LARGE SCALE ASCENT.
THE ECMWF IS A BIT OF AN OUTLIER AS IT IS SLIGHTLY SLOWER THAN THE
OTHERS...AND THUS EXHIBITING PRECIP LINGERING THROUGH TOMORROW
AFTN. WILL LEAN TOWARDS THE FORMER SOLUTIONS ATTM...GIVEN BETTER
CONSISTENCY. A 1020+ MB SFC RIDGE WELL NORTH OF THE REGION WILL BE
THE DRIVING FORCE BEHIND THE COLD FRONT...SET TO INTRUDE THE
REGION TONIGHT AND BE LOCATED ACROSS THE PERMIAN BASIN BY TOMORROW
MORNING. INITIAL PRESSURE RISES OF 12 MB/3 HR WILL HAVE RELAXED
SUBSTANTIAL AT THE START OF THE EXTENDED PERIOD...HOWEVER 850 MB
TEMPS HOVERING NEAR THE FREEZING MARK DURING THE DAY TOMORROW
SUGGEST TEMPS IN THE 40S AND 50S...OR SOME 15-20 DEGREES BELOW
NORM.
THE AFOREMENTIONED SFC RIDGE WILL SHIFT SOUTH TO ACROSS THE CWA
TOMORROW NIGHT THUS PROMOTING LIGHT AND VARIABLE WINDS...IN ADDITION
TO MAINTAINING 850 MB TEMPS NEAR/SLIGHTLY BELOW FREEZING. IT IS NO
WONDER MOS GUIDANCE HINTS AT OVERNIGHT TEMPS RIGHT AT OR BELOW
FREEZING ACROSS THE ENTIRE CWA. SINCE WE ARE JUST ENTERING THE
GROWING SEASON THIS OF COURSE RAISES CONCERN. WILL ADD STRONG
WORDING TO THE HAZARDOUS WEATHER OUTLOOK ATTM...HOWEVER A
FREEZE WATCH/WARNING MAY BE REQUIRED AND WILL LET LATER SHIFTS
ANALYZE FUTURE MODEL RUNS TO SEE IF THIS IS INDEED WARRANTED.
BROAD CYCLONIC FLOW ALOFT WILL BECOME NWRLY BY THURSDAY...WHILST SFC
RIDGING TRANSLATES AWAY FROM THE REGION...AND THE DEVELOPMENT OF SFC
LEE TROUGHING ENCOURAGES A RETURN TO SRLY FLOW AND THUS WARMER
TEMPS /UPPER 60S TO LOW TO MID 70S BY FRIDAY/. THEREAFTER...A FRONT IS
PROGGED TO MOVE ACROSS MOST OF THE CWA FRIDAY NIGHT /PRODUCING THE
DEVELOPMENT OF MID-LEVEL CLOUDINESS/...AHEAD OF AN EMBEDDED
DISTURBANCE IN THE FLOW ALOFT...SET TO MOVE ACROSS THE REGION
FRIDAY NIGHT. MODELS CONTINUE TO SHOW LIGHT QPF SIGNALS MAINLY ACROSS
THE NERN ZONES DURING THE SAID TIME PERIOD...AND HAVE ELECTED TO
INCREASE POPS TO 14 PERCENT...JUST BELOW MENTIONABLE LEVELS ATTM.
SFC LEE CYCLOGENESIS WILL RESUME FOR THE WEEKEND THROUGH EARLY NEXT
WEEK...LEADING TOWARDS TEMPS WARMING INTO THE 70S AND 80S. AS
SUCH...A DRYLINE WILL SHARPEN AND LINGER ACROSS THE FA. LONG TERM
SOLUTIONS SHOW RATHER PROGRESSIVE FLOW ACROSS THE NRN CONUS...AND
ONE OF THOSE DISTURBANCES WILL SEND A BACKDOOR COLD FRONT TOWARDS
THE SERN TEXAS PANHANDLE MONDAY. COULD SEE PRECIP DEVELOP ALONG THE
DRYLINE AND COLD FRONTAL BOUNDARY INTERSECTION ACROSS THE ROLLING
PLAINS...BUT HAVE KEPT POPS SILENT AND WILL AWAIT TO SEE IF THIS
PATTERN AND ASSOCIATED MESO-SCALE FEATURES ARE CONSISTENT FROM RUN TO
RUN.
FIRE WEATHER...
MARGINALLY CRITICAL CONDITIONS POSSIBLE FOR A TIME THIS AFTERNOON
WITH THE MAIN LIMITING FACTOR BEING RELATIVE HUMIDITY. HAVE LOWERED
FCST RH A LITTLE THIS MORNING WITH EXPECTATION OF SLIGHTLY WARMER
TEMPS THAN PREVIOUSLY EXPECTED. THAT WILL BRING MINIMUM RH VALUES
NEAR 15 PCT FOR MUCH OF THE AREA WHILE WINDS SHOULD FAIRLY EASILY
EXCEED 20 MPH AT THE 20-FOOT LEVEL. SOME QUESTION TOO OF HOW MUCH
THOSE TWO WILL OVERLAP WITH POSSIBILITY OF THE WIND SPEEDS MAXING
OUT A LITTLE AHEAD OF THE RH BOTTOM. SHOULD SEE SOME PERIODS OF
CRITICAL CONDITIONS AS RH FLIRTS WITH THE 15 PCT CRITERIA...BUT
PRETTY UNCERTAIN WITH RESPECT TO DURATION. GIVEN UNCERTAINTIES AS
WELL AS GOOD RH RECOVERY FOR ALMOST ALL OF THE FCST AREA THIS
MORNING WILL OPT FOR A FIRE DANGER STATEMENT OVER A RED FLAG WARNING
ATTM.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 20 48 25 64 35 / 30 0 0 0 0
TULIA 24 49 24 63 36 / 30 10 0 0 0
PLAINVIEW 26 51 25 63 38 / 30 10 0 0 0
LEVELLAND 26 53 27 66 40 / 20 0 0 0 0
LUBBOCK 30 53 27 66 41 / 20 10 0 0 0
DENVER CITY 29 55 27 68 44 / 10 0 0 0 0
BROWNFIELD 30 55 27 67 42 / 10 0 0 0 0
CHILDRESS 33 51 27 65 39 / 40 10 0 0 0
SPUR 35 55 29 66 40 / 20 10 0 0 0
ASPERMONT 37 55 30 66 42 / 20 10 0 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/99/05
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
1125 AM CDT TUE APR 9 2013
.UPDATE...
AT 11 AM THIS MORNING...A LARGE UPPER LEVEL LOW WAS MOVING
ACROSS NORTHERN NEW MEXICO WITH THE BASE OF THE UPPER LEVEL TROUGH
SWINGING DOWN INTO EXTREME NORTHERN MEXICO. AT THE SURFACE...A
COLD FRONT WAS MOVING AHEAD OF SCHEDULE THROUGH THE TEXAS
PANHANDLE WITH A DRYLINE EXTENDING DOWN THROUGH FAR WEST TEXAS.
THE COLD FRONT WAS LOCATED JUST NORTH OF PLAINVIEW TEXAS EXTENDING
BACK TO THE NORTHEAST TO WOODWARD OKLAHOMA AND MEDICINE LODGE
KANSAS. TEMPERATURES BEHIND THE FRONT ARE IN THE 30S WITH WINDS
GUSTING AROUND 40 MPH AT SEVERAL LOCATIONS. THESE CONDITIONS ARE
QUICKLY ACCELERATING THE FRONT FASTER THAN PREVIOUSLY THOUGHT BUT
THE 12Z NAM AND RAP HAVE PICKED UP ON THE FASTER FRONTAL LOCATION.
UNFORTUNATELY THE 12Z GFS IS STILL MUCH TOO SLOW AND HAD TO BE
DISCOUNTED FOR MUCH OF THE UPDATE.
BY MID AFTERNOON THE DRYLINE WILL BE LOCATED ALONG THE WESTERN
BORDER OF THE CWA WITH THE COLD FRONT ALREADY MOVING ACROSS
SOUTHWESTERN OKLAHOMA AND NORTHWEST TEXAS. THE COLD FRONT WILL
QUICKLY OVERTAKE THE DRYLINE BY THE LATE AFTERNOON/EARLY EVENING
HOURS JUST NORTHWEST OF THE AREA AND WILL START TO ENTER OUR
NORTHWESTERN COUNTIES BY 10 PM. WITH THIS FASTER TIMING...THIS
FURTHER LIMITS THE POTENTIAL FOR STORMS TO DEVELOP ON THE DRYLINE
THIS AFTERNOON. HAVE UPDATED ALL APPROPRIATE FORECAST PARAMETERS
THROUGH TOMORROW TO REFLECT THE LOCATION OF THE DRYLINE AND THE
FASTER FRONTAL ARRIVAL AND MOVEMENT.
REGARDING THE SEVERE WEATHER POTENTIAL FOR LATER TODAY AND
TONIGHT. UNCERTAINTY STILL REMAINS ON IF STORMS WILL DEVELOP ON
THE DRYLINE NEAR OUR WESTERN AND/OR NORTHWESTERN COUNTIES. THE 12Z
FWD SOUNDING THIS MORNING SHOWS A VERY LARGE CAP STILL IN PLACE
AND MODIFYING THE SOUNDING FOR AFTERNOON TEMPERATURES IN THE MID
80S STILL REVEALS A STRONG CAP OVER -100 J/KG. WE WILL BE DOING A
SPECIAL 18Z SOUNDING THIS AFTERNOON AND WILL SEE HOW THE CAP HAS
CHANGED SINCE 12Z THIS MORNING. WE CONTINUE TO MAINTAIN THE
THINKING THAT THE CAP WILL HOLD OVER THE AREA THIS AFTERNOON BUT
WE DO NOT DISCOUNT THAT THERE IS A NARROW WINDOW AROUND 5-7 PM
DURING WHICH THE CAP COULD BE BREACHED BEFORE THE FRONT TAKES OVER
THE DRYLINE. HOWEVER...WITH THE MAIN UPPER LEVEL LIFT STILL WEST
OF THE REGION AT THAT TIME...IT WILL LIKELY BE VERY DIFFICULT TO
DEVELOP ANY STORMS ALONG THE DRYLINE. BUT ANY STORM THAT IS ABLE
TO DEVELOP ON THE DRYLINE WOULD HAVE A THREAT FOR LARGE
HAIL...DAMAGING WINDS...AND POSSIBLY A TORNADO. THESE STORMS WOULD
BE MOVING TO THE NORTHEAST AND WOULD LIKELY ONLY POSE A THREAT TO
A FEW OF OUR NORTHWESTERN COUNTIES FROM STEPHENS TO MONTAGUE
COUNTY.
AS THE COLD FRONT MOVES THROUGH THE REGION OVERNIGHT...A LINE OF
STORMS WILL LIKELY OCCUR ALONG THE LEADING EDGE WITH A THREAT FOR
SCATTERED SEVERE STORMS ALONG THE LINE...MAINLY FROM 10 PM THROUGH
6 AM. IN ADDITION...CONVECTION WILL LIKELY ALSO BE OCCURRING BEHIND
THE LEADING EDGE OF THE FRONT AND SOUNDINGS STILL SUPPORT THE
POTENTIAL FOR HAIL WITH THESE STORMS IF THEY CAN REACH THROUGH THE
REDEVELOPING CAP OVERNIGHT.
82/JLD
&&
.AVIATION...
PERSISTENCE WILL BE THE KEY REGARDING SURFACE WINDS TODAY AS
STRONG LOW LEVEL FLOW CONTINUES AHEAD OF THE STORM SYSTEM
CURRENTLY OVER THE 4-CORNERS REGION. WILL MAINTAIN THE FORECAST OF
SUSTAINED WINDS IN THE 15-20KT RANGE UP UNTIL THE PASSAGE OF THE
FRONT TONIGHT. MEANWHILE...STRATUS WITHIN THE 50+ KT LOW LEVEL JET
CONTINUES TO STREAM OVERHEAD. BREAKS IN THE CLOUD FIELD CAN BE
SEEN ON 11-3.9 MICRON IMAGERY SO CIGS WILL LIKELY VARY BETWEEN VFR
AND MVFR AT ALL SITES THIS MORNING.
FOR TONIGHT...A STRONG COLD FRONT PROJECTED TO ADVANCE
SOUTHEASTWARD ACROSS NORTH TEXAS WILL LIKELY BE ACCOMPANIED BY
A ROUND OF SHOWERS AND STORMS. A BLEND OF THE LATEST MODEL GUIDANCE
INDICATES FROPA IN THE METROPLEX 08-09Z AND CLOSER TO 12Z AT KACT.
STRONG NORTH-NORTHWESTERLY WINDS WILL OCCUR WEDNESDAY FOLLOWING
THE PASSAGE OF THE FRONT...WITH MVFR CONDITIONS LINGERING THROUGH
MUCH OF THE DAY.
30
&&
.PREV DISCUSSION... /ISSUED 352 AM CDT TUE APR 9 2013/
ANOTHER MOSTLY CLOUDY...BREEZY AND WARM DAY IS IN STORE FOR NORTH
TEXAS TODAY AHEAD OF AN APPROACHING UPPER LEVEL STORM SYSTEM AND
ASSOCIATED COLD FRONT. AS OF 3 AM THE COLD FRONT HAD ALREADY MOVED
INTO SOUTHEAST COLORADO AND NORTHWEST KANSAS WITH WIND GUSTS
BEHIND THE FRONT AS HIGH AS 58 MPH. THE AIR BEHIND THE FRONT IS
VERY COLD FOR EARLY APRIL WITH TEENS AND 20S ACROSS PARTS OF
WYOMING AND NEBRASKA. THE COLD FRONT WILL CONTINUE TO SURGE SOUTH
TODAY BUT SHOULD SLOW A BIT DUE TO BOUNDARY LAYER MIXING ON THE
LEADING EDGE. THE DRY LINE WILL ALSO MIX EASTWARD THROUGH THE DAY
AND SHOULD APPROACH THE EXTREME WESTERN ZONES BEFORE SUNSET. THE
COLD FRONT SHOULD OVERTAKE THE DRYLINE DURING EVENING AND MOVE
QUICKLY ACROSS NORTH TEXAS OVERNIGHT/WEDNESDAY MORNING.
THE MOST LIKELY SCENARIO WHERE THUNDERSTORMS ARE CONCERNED IS
THAT THE STRONG CAP THAT IS CURRENTLY IN PLACE ACROSS THE REGION
WILL WEAKEN THROUGH THE DAY AS LARGE SCALE LIFT INCREASES. THE CAP
MAY BREAK IN THE EXTREME NORTHWEST ZONES JUST BEFORE SUNSET WITH
RAPID THUNDERSTORM DEVELOPMENT POSSIBLE. HOWEVER...CONFIDENCE IS
LOW THAT THE CAP WILL BREAK BEFORE THE COLD FRONT ARRIVES THIS
EVENING...AND THIS IS SUPPORTED BY THE 4 KM WRF AND TTU WRF.
THEREFORE...WILL LEAVE ONLY LOW LATE AFTERNOON POPS IN THE EXTREME
NORTHWEST ZONES ON THE OUTSIDE CHANCE THAT THE CAP BREAKS. IF ANY
STORMS DO DEVELOP BEFORE SUNSET...THEY WILL HAVE SUFFICIENT
INSTABILITY AND SHEAR TO SUPPORT SUPERCELL FORMATION.
THE CAP SHOULD BREAK BY LATE EVENING AS THE COLD FRONT BEGINS TO
MOVE THROUGH THE REGION. STORMS THAT DEVELOP ALONG OR JUST AHEAD
OF THE COLD FRONT WILL HAVE A GOOD CHANCE OF BECOMING SEVERE WITH
DAMAGING WINDS AND LARGE HAIL. AN ISOLATED TORNADO CAN NOT BE
RULED OUT BUT FEEL THE TIME OF DAY AND SPEED OF THE FRONT MAY
LIMIT THE POTENTIAL. THE HIGH RES MODELS CONTINUE TO SHOW THE
FRONT MOVING QUICKLY THROUGH THE REGION WITH POST-FRONTAL...MAINLY
NON SEVERE...THUNDERSTORMS OVERNIGHT/WEDNESDAY MORNING. THE GOOD
NEWS IS THAT THE WINDOW SEVERE WEATHER IN ANY ONE AREA SHOULD BE SMALL
WITH A MUCH LARGER WINDOW OF TIME FOR MUCH NEEDED POST-FRONTAL
PRECIPITATION. ALL SHOWERS AND STORMS SHOULD END FROM WEST TO EAST
ON WEDNESDAY AS MUCH DRIER AND COLDER AIR MOVES IN.
THE NEXT CHALLENGE WITH THIS FORECAST WILL BE THE POST-FRONTAL
TEMPERATURES. THE NAM CONTINUES TO BE THE COLDEST OF THE SOLUTIONS
AND BASED ON LATEST SURFACE ANALYSIS...IT SEEMS TO HAVE THE BEST
HANDLE ON THE COLD AIR. EXPECT AFTERNOON HIGHS WEDNESDAY TO ONLY
REACH THE LOWER 50S IN THE NORTHWEST ZONES BUT THE SOUTHEAST SHOULD
STILL BE IN THE UPPER 60S TO LOWER 70S. CLEARING SKIES AND
DECREASING WIND SPEEDS WEDNESDAY NIGHT WILL ALLOW TEMPS TO FALL
INTO THE 30S TO LOWER 40S. IT APPEARS THAT ONLY THE NORTHWEST
ZONES WILL APPROACH FREEZING BRIEFLY AROUND SUNRISE THURSDAY
MORNING. TEMPERATURES WILL BEGIN TO REBOUND ON THURSDAY AFTERNOON AS
SURFACE HIGH PRESSURE MOVES TO THE EAST. THE WARMING TREND WILL
CONTINUE THROUGH THE WEEKEND AS LOW LEVEL MOISTURE RETURNS TO THE
REGION. WEST TO SOUTHWEST FLOW ALOFT AND A PERSISTENT LEE TROUGH
WILL KEEP WARM AND RAIN-FREE WEATHER ACROSS NORTH TEXAS THROUGH
EARLY NEXT WEEK.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 82 50 57 38 62 / 10 90 60 10 0
WACO, TX 84 60 62 39 64 / 10 90 70 10 5
PARIS, TX 82 60 62 37 57 / 10 90 70 20 5
DENTON, TX 82 47 55 35 61 / 10 90 60 10 0
MCKINNEY, TX 82 52 58 35 59 / 10 90 60 10 5
DALLAS, TX 83 53 59 39 61 / 10 90 70 10 0
TERRELL, TX 83 59 61 35 60 / 10 90 70 10 5
CORSICANA, TX 84 63 65 35 64 / 10 70 80 10 5
TEMPLE, TX 84 63 64 39 64 / 10 80 80 10 5
MINERAL WELLS, TX 84 42 51 33 63 / 10 90 40 10 0
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
58/82
AREA FORECAST DISCUSSION
NWS LUBBOCK TX
1004 AM CDT TUE APR 9 2013
.UPDATE...
THE COLD FRONT HAS PASSED THROUGH FRIONA...DIMMITT...AND HAPPY
ALREADY QUITE A BIT AHEAD OF SCHEDULE. SHORT TERM SURFACE PRESSURE
RISES HAVE WEAKENED BUT THE FRONT WAS CONTINUING TO ADVANCE ON
LARGER SCALE PUSHES. WE HAVE ACCEPTED THE LATEST RAP RUN FOR NOW
AND UPDATED FOR THE FRONT TO WORK THROUGH MOST OF THE NORTHERN
AREA BEFORE STALLING AROUND MIDDAY. TEMPERATURES LOWERED ACROSS
NORTHERN ZONES AND WARMED SLIGHTLY SOME SOUTHERN AREAS. THE FRONT
MAY BE ABLE TO CATCH UP TO THE MOISTURE LYING OVER THE NORTHERN
ROLLING PLAINS AND GIVE A VALID LOW CHANCE FOR THUNDER. WE WILL
STUDY FURTHER FOR SEVERE CHANCES AS WELL. RMCQUEEN
&&
.PREV DISCUSSION... /ISSUED 623 AM CDT TUE APR 9 2013/
AVIATION...
MVFR CIGS DEVELOPING IN MOIST AIR THAT HAS MOVED BACK INTO THE
FCST AREA WILL PERSIST UNTIL LOW LEVEL WINDS BEGIN TO VEER TO THE
SW AND INCREASE IN SPEED. THAT IS LIKELY TO OCCUR BY 14Z AT KLBB
AND 17Z AT KCDS. AFTERWARDS...GUSTY SW WINDS EXPECTED THROUGH THE
DAY FOLLOWED BY GUSTY NORTH WINDS BEHIND A STRONG COLD FRONT THAT
WILL MOVE THROUGH THE FCST AREA THIS EVENING. POTENTIAL FOR SOME
LIGHT SHOWERS OVERNIGHT WITH THE APPROACH OF AN UPPER LEVEL
DISTURBANCE FAVORS KCDS OVER KLBB.
PREV DISCUSSION... /ISSUED 319 AM CDT TUE APR 9 2013/
SHORT TERM...
RATHER DYNAMIC PATTERN SETTING UP FOR THE NEXT 24 HOURS AS A STRONG
UPPER LOW EJECTS FROM THE 4-CORNERS TO THE CNTL PLAINS WHILE THE
PARENT TROUGH MOVES FROM WEST TO EAST TOWARD THE FCST AREA.
INITIALLY A MID LEVEL JET WILL PUNCH ACROSS THE AREA AS IT ROTATES
NEWD WITH THE UPPER LOW. PROGGED MAGNITUDE OF THIS JET HAS WEAKENED
RELATIVE TO RECENT MODEL RUNS WITH 500 MB SPEEDS OF AROUND 90 KTS
AND 700 MB ABOUT HALF THAT. MIXING WILL BE FAIRLY EFFICIENT DESPITE
COOLER TEMPERATURES THAN THE LAST FEW DAYS COURTESY OF LOWERING
HEIGHTS AND THICKNESSES WITH THE ADVANCING UPPER TROUGH. THIS SHOULD
RESULT IN WINDS MOSTLY IN A RANGE OF 20 TO 30 MPH...PERIODICALLY
SLIGHTLY STRONGER UP ON THE CAPROCK...ATTM NOT EXPECTED TO BE QUITE
STRONG ENOUGH TO JUSTIFY A WIND ADVISORY. THIS MID LEVEL JET MAX
WILL HELP QUICKLY MIX THE DRYLINE EWD THROUGH THE FCST AREA WITH LOW
DEW POINT AIR MOVING IN BEHIND IT AND EFFECTIVELY KILLING ANY PRECIP
CHANCES DURING THE AFTN.
THAT LOOKS TO CHANGE OVERNIGHT AS THE UPPER TROUGH CONTINUES TO
ADVANCE TOWARD THE AREA. MID LEVEL LIFT AND MOISTURE ASSOCIATED WITH
THE TROUGH LIKELY SUFFICIENT TO PRODUCE SOME ELEVATED SHOWERS ACROSS
MAINLY THE NRN HALF OF THE FCST AREA WHERE THAT COMBINATION WILL BE
GREATEST. STILL DO NOT EXPECT ANYTHING MORE THAN A SCATTERED NATURE
TO THE SHOWERS AND 30 TO 40 PCT POPS THERE LOOK REASONABLE. FCST
FURTHER COMPLICATED BY A STRONG COLD FRONT THAT WILL MOVE QUICKLY
THROUGH THE FCST AREA DURING THE EVENING HOURS. THIS FRONT WILL
USHER IN VERY COLD AIR THE STRENGTH OF WHICH IS INDICATED BY
TEMPERATURES IN THE TEENS AND 20S ACROSS SERN WYOMING AND NERN
COLORADO PENETRATING SWD DOWN THE LEE OF THE FRONT RANGE. THAT FRONT
IS JUST SOUTH OF A TRINIDAD COLO TO SPRINGFIELD COLO TO COLBY KS
LINE AT 08Z. THIS IS JUST A BIT AHEAD OF WRF-NAM POSITIONING. THE
FRONT WILL MOVE INTO THE TEXAS PANHANDLE THIS MORNING WHERE IT
SHOULD STALL IN THE FACE OF WARM TEMPS AND SW WINDS...BUT THEN
QUICKLY ACCELERATE SWD LATE THIS AFTN OR EARLY THIS EVENING. COLD AIR
THAT COMES IN BEHIND THE FRONT MAY BE COLD ENOUGH TO PRODUCE SOME
FROZEN PRECIP BEFORE PRECIP COMES TO AN END TONIGHT...AND WILL
MAINTAIN THAT WORDING IN THE FCST WITH ONLY MINOR ADJUSTMENTS TO
AREAL EXTENT. PRESSURE RISES BEHIND THE FRONT LIKELY TO BE FAIRLY
STRONG WITH SOME POTENTIAL FOR WIND ADVISORY SPEEDS FOR A TIME
OVERNIGHT.
LONG TERM...
PER THE NAM...GFS AND CMC SOLUTIONS...THE MEAN TROUGH OF THE BROAD UA
LOW ACROSS THE CENTRAL PLAINS WILL CONTINUE TO SWING EAST ACROSS THE
ROLLING PLAINS TOMORROW MORNING...WHILST THE BEST PRECIP WILL
SHIFT EAST OF THE CWA THUS COINCIDING WITH BEST LARGE SCALE ASCENT.
THE ECMWF IS A BIT OF AN OUTLIER AS IT IS SLIGHTLY SLOWER THAN THE
OTHERS...AND THUS EXHIBITING PRECIP LINGERING THROUGH TOMORROW
AFTN. WILL LEAN TOWARDS THE FORMER SOLUTIONS ATTM...GIVEN BETTER
CONSISTENCY. A 1020+ MB SFC RIDGE WELL NORTH OF THE REGION WILL BE
THE DRIVING FORCE BEHIND THE COLD FRONT...SET TO INTRUDE THE
REGION TONIGHT AND BE LOCATED ACROSS THE PERMIAN BASIN BY TOMORROW
MORNING. INITIAL PRESSURE RISES OF 12 MB/3 HR WILL HAVE RELAXED
SUBSTANTIAL AT THE START OF THE EXTENDED PERIOD...HOWEVER 850 MB
TEMPS HOVERING NEAR THE FREEZING MARK DURING THE DAY TOMORROW
SUGGEST TEMPS IN THE 40S AND 50S...OR SOME 15-20 DEGREES BELOW
NORM.
THE AFOREMENTIONED SFC RIDGE WILL SHIFT SOUTH TO ACROSS THE CWA
TOMORROW NIGHT THUS PROMOTING LIGHT AND VARIABLE WINDS...IN ADDITION
TO MAINTAINING 850 MB TEMPS NEAR/SLIGHTLY BELOW FREEZING. IT IS NO
WONDER MOS GUIDANCE HINTS AT OVERNIGHT TEMPS RIGHT AT OR BELOW
FREEZING ACROSS THE ENTIRE CWA. SINCE WE ARE JUST ENTERING THE
GROWING SEASON THIS OF COURSE RAISES CONCERN. WILL ADD STRONG
WORDING TO THE HAZARDOUS WEATHER OUTLOOK ATTM...HOWEVER A
FREEZE WATCH/WARNING MAY BE REQUIRED AND WILL LET LATER SHIFTS
ANALYZE FUTURE MODEL RUNS TO SEE IF THIS IS INDEED WARRANTED.
BROAD CYCLONIC FLOW ALOFT WILL BECOME NWRLY BY THURSDAY...WHILST SFC
RIDGING TRANSLATES AWAY FROM THE REGION...AND THE DEVELOPMENT OF SFC
LEE TROUGHING ENCOURAGES A RETURN TO SRLY FLOW AND THUS WARMER
TEMPS /UPPER 60S TO LOW TO MID 70S BY FRIDAY/. THEREAFTER...A FRONT IS
PROGGED TO MOVE ACROSS MOST OF THE CWA FRIDAY NIGHT /PRODUCING THE
DEVELOPMENT OF MID-LEVEL CLOUDINESS/...AHEAD OF AN EMBEDDED
DISTURBANCE IN THE FLOW ALOFT...SET TO MOVE ACROSS THE REGION
FRIDAY NIGHT. MODELS CONTINUE TO SHOW LIGHT QPF SIGNALS MAINLY ACROSS
THE NERN ZONES DURING THE SAID TIME PERIOD...AND HAVE ELECTED TO
INCREASE POPS TO 14 PERCENT...JUST BELOW MENTIONABLE LEVELS ATTM.
SFC LEE CYCLOGENESIS WILL RESUME FOR THE WEEKEND THROUGH EARLY NEXT
WEEK...LEADING TOWARDS TEMPS WARMING INTO THE 70S AND 80S. AS
SUCH...A DRYLINE WILL SHARPEN AND LINGER ACROSS THE FA. LONG TERM
SOLUTIONS SHOW RATHER PROGRESSIVE FLOW ACROSS THE NRN CONUS...AND
ONE OF THOSE DISTURBANCES WILL SEND A BACKDOOR COLD FRONT TOWARDS
THE SERN TEXAS PANHANDLE MONDAY. COULD SEE PRECIP DEVELOP ALONG THE
DRYLINE AND COLD FRONTAL BOUNDARY INTERSECTION ACROSS THE ROLLING
PLAINS...BUT HAVE KEPT POPS SILENT AND WILL AWAIT TO SEE IF THIS
PATTERN AND ASSOCIATED MESO-SCALE FEATURES ARE CONSISTENT FROM RUN TO
RUN.
FIRE WEATHER...
MARGINALLY CRITICAL CONDITIONS POSSIBLE FOR A TIME THIS AFTERNOON
WITH THE MAIN LIMITING FACTOR BEING RELATIVE HUMIDITY. HAVE LOWERED
FCST RH A LITTLE THIS MORNING WITH EXPECTATION OF SLIGHTLY WARMER
TEMPS THAN PREVIOUSLY EXPECTED. THAT WILL BRING MINIMUM RH VALUES
NEAR 15 PCT FOR MUCH OF THE AREA WHILE WINDS SHOULD FAIRLY EASILY
EXCEED 20 MPH AT THE 20-FOOT LEVEL. SOME QUESTION TOO OF HOW MUCH
THOSE TWO WILL OVERLAP WITH POSSIBILITY OF THE WIND SPEEDS MAXING
OUT A LITTLE AHEAD OF THE RH BOTTOM. SHOULD SEE SOME PERIODS OF
CRITICAL CONDITIONS AS RH FLIRTS WITH THE 15 PCT CRITERIA...BUT
PRETTY UNCERTAIN WITH RESPECT TO DURATION. GIVEN UNCERTAINTIES AS
WELL AS GOOD RH RECOVERY FOR ALMOST ALL OF THE FCST AREA THIS
MORNING WILL OPT FOR A FIRE DANGER STATEMENT OVER A RED FLAG WARNING
ATTM.
&&
.PRELIMINARY POINT TEMPS/POPS...
FRIONA 56 20 48 25 64 / 10 30 0 0 0
TULIA 65 24 49 24 63 / 10 30 10 0 0
PLAINVIEW 70 26 51 25 63 / 10 30 10 0 0
LEVELLAND 74 26 53 27 66 / 10 20 0 0 0
LUBBOCK 76 30 53 27 66 / 0 20 10 0 0
DENVER CITY 75 29 55 27 68 / 10 10 0 0 0
BROWNFIELD 75 30 55 27 67 / 10 10 0 0 0
CHILDRESS 71 33 51 27 65 / 10 40 10 0 0
SPUR 84 35 55 29 66 / 0 20 10 0 0
ASPERMONT 89 37 55 30 66 / 0 20 10 0 0
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
05/99
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
1253 AM CDT THU APR 11 2013
.MESOSCALE DISCUSSION...
655 PM CDT
A CONTINUED INCREASE IN CONVECTION IS EXPECTED ACROSS CENTRAL IL
PROGRESSING NORTHEAST INTO THE FORECAST AREA...WITH A CHANCE FOR
RAINFALL EXCEEDING FLOOD GUIDANCE IN SOME AREAS...ALONG WITH THE
SLIGHT RISK OF A SEVERE STORM OR TWO...ESPECIALLY ACROSS THE NEW
WATCH AREA.
LATEST HAND SURFACE ANALYSIS INDICATES THE SURFACE BOUNDARY
REMAINS STATIONARY FROM SOUTHWEST IL ENE THROUGH CENTRAL IN. THE
SURFACE LOW IN EAST CENTRAL MO CONTINUES TO EVOLVE NORTHEAST BUT
THE BOUNDARY SHOULD ADVANCE LITTLE NORTHWARD WITH REGENERATING
CONVECTION. WHILE STORMS HAD BEEN MAINLY FOCUSED ALONG THE
BOUNDARY IN CENTRAL IL DURING THE AFTERNOON...THE LAST HOUR TO TWO
HAS SHOWN A TREND FOR MUCH MORE DEVELOPMENT TO THE NORTH OF THAT
AS WARM AND MOIST ADVECTION IN THE LOW-LEVEL JET LAYER INCREASES.
IR IMAGERY CONTINUES TO SHOW COOLING CLOUD TOPS FROM THIS AREA OF
CONVECTION AS WELL AS THE LARGE BATCH IN MO TO FAR WEST CENTRAL
IL.
THIS LOW-LEVEL JET WILL CONTINUE TO INCREASE WITH IMPRESSIVE
MOISTURE TRANSPORT AND REPLENISHMENT ADVANCING NORTHWARD THROUGH
THE EVENING...ESPECIALLY BETWEEN 03Z AND 08Z. SHOWERS AND EMBEDDED
STORMS SHOULD BE PLENTIFUL IN THE CWA DURING THIS TIME. THIS LOW-
LEVEL JET INCREASE WILL ALL BE A RESULT OF MID TO UPPER LEVEL
FORCING AND DIFFLUENCE INCREASING WITH THE UPPER TROUGH ADVANCING
EASTWARD...AND ANOTHER LEAD SHORT WAVE NEAR THE KS/MO BORDER. THIS
SHORT WAVE AND ASSOCIATED 60 KT 700 MB FLOW SHOULD HELP TO SUSTAIN
MORE THAN EFFICIENT SHEAR TO ORGANIZE CONVECTION ON THE LOW-LEVEL
JET NOSE AND ELEVATED THERMAL BOUNDARY ACROSS THE SOUTHERN THIRD
TO HALF OF THE FORECAST AREA. ELEVATED INSTABILITY OF 500-1000
J/KG IS ANALYZED ACROSS THE SOUTH AND ADAPTING AN AMDAR SOUNDING
FOR RAP FORECAST 850 T/TDS AT 03Z INDICATES PARCELS SHOULD BE NEAR
THAT UPPER BOUND IN THE SOUTHERN FORECAST AREA. SOME OF THE
CONVECTIVE ALLOWING GUIDANCE DOES SHOW A FOCUSED CIRCULATION
/ALMOST MCV-LIKE/ ACROSS THE SOUTHERN AREA. WHILE NORTH OF THE
BOUNDARY BY QUITE A DISTANCE...THE EFFECTIVE SHEAR OF 50-70 KT
FORECAST BY THE RAP OVER THE FAR SOUTHERN CWA AND ADJACENT
COUNTIES IS SUFFICIENT FOR POTENTIAL BOWING STRUCTURES ABLE TO
PUSH WIND DOWN. WE DID SEE SOME OF THAT WITH A SIMILAR COMPLEX
THIS MORNING TOWARD ROCHELLE.
THE HEAVY RAIN THREAT CONTINUES WITH NOT ONLY HIGH MOISTURE
VALUES FOR EFFICIENT RAIN PRODUCERS /700 MB DEW POINTS NEAR
4C/...BUT FORECAST STORM MOTION FOR PRECIP TRAINING ALONG THE
ELEVATED STATIONARY BOUNDARY. SUCH BEHAVIOR HAS ALREADY BEEN
OBSERVED WITH SOME OF THE STORMS IN CENTRAL IL. AREAS IN THE FAR
SOUTHEAST DID RECEIVE A RADAR ESTIMATED ONE AND A HALF TO THREE
INCHES OF RAIN EARLIER AND ARE MORE VULNERABLE...WHICH IS WHERE
THE CURRENT FLOOD ADVISORY IS IN EFFECT. WILL BE KEEPING A CLOSE
EYE ON RAINFALL RATES BUT ALL IN ALL FORECAST QPF FROM EARLIER
STILL LOOKS ON TRACK...BASICALLY A WIDESPREAD ONE TO ONE AND A
HALF INCHES TONIGHT...WITH THE ISOLATED HIGHER AMOUNTS NAMELY
SOUTH OF I-80.
MTF
&&
.DISCUSSION...
358 PM CDT
SHORT TERM...LATE THIS AFTERNOON AND TONIGHT...
NEXT SHORT WAVE LIFTING UP THE E SIDE OF THE PLAINS UPPER TROF
IS MOVING NORTHEASTWARD OVER IA AT MID AFTERNOON. AS IT HAS BEEN
APPROACHING A BROAD AREA OF RAIN HAD SPREAD FAR AS SOUTHERN WI
AND N CENTRAL IL WHILE S OF THE SURFACE BOUNDARY...THAT HAD
RETREATED BACK TO CENTRAL IL THIS MORNING...THUNDERSTORMS HAD
BROKEN OUT. WHILE SOME OF THESE THUNDERSTORMS AND HEAVIER SHOWERS
WERE BEING CARRIER NE OVER THE FAR SOUTHERN PORTION OF THE LOCAL
FORECAST AREA BY THE MEAN FLOW THEY QUICKLY BECOME ELEVATED DUE
TO THE VERY STABLE BOUNDARY LAYER IN PLACE N OF SAID BOUNDARY.
DEW POINTS S OF THE BOUNDARY RISE ARE IN THE LOWER AND MID 60S
WITH UPPER 60S FURTHER S. WITH PARTLY CLOUD SKIES OVER ABOUT THE
S HALF OF IL IT HAS BECOME QUITE UNSTABLE DOWNSTATE AS TEMPS HAVE
WARMED. WITH THE SHORT WAVE NOTED ABOVE TO MOVE ESE THEN E OVER
SOUTHERN WI AND FAR NORTHERN IL DURING THE LATE AFTERNOON AND
VERY EARLY EVENING AS IT APPROACHES AND THEN TOPS THE UPPER RIDGE
DOWN STREAM FROM THE CENTRAL U.S. TROF RAIN COVERAGE IS EXPECTED
TO TEMPORARILY DECREASE FOR THE REST OF THE FIRST HALF OF THE
EVENING. THIS SHORT WAVE PASSING BY IS ALSO EXPECTED TO KEEP THE
QUASI-STATIONARY FRONT DOWN ACROSS CENTRAL IL OR EVEN GIVE IT A
SLIGHT NUDGE FURTHER S THIS EVENING.
AS WE GET INTO LATER THIS EVENING AND OVERNIGHT YET ANOTHER SHORT
WAVE...CURRENTLY LIFTING NE FROM FAR NE TX IS TO LIFT TO EASTERN
IA AND NORTHERN IL BY THU MORNING. AS IT MOVES CLOSER LATER
TONIGHT EXPECT ANOTHER BROAD AREA OF RAIN TO DEVELOP AND SPREAD
ACROSS THE FORECAST AREA. WHILE THE LATE AFTERNOON-EARLY EVENING
RAIN IS NOT EXPECTED TO HAVE MUCH IF ANY THUNDERSTORMS ASSOCIATED
WITH IT AS THE BOUNDARY LAYER WILL REMAIN VERY STABLE AND
TEMPERATURE PROFILES ALOFT DO NOT LOOK ESPECIALLY CONDUCIVE TO
UPDRAFT DEVELOPMENT THE RAIN LATER THIS EVENING AND OVERNIGHT WILL
LIKELY HAVE SOME EMBEDDED ELEVATED THUNDERSTORMS AS SOME MINOR
MID LEVEL COOLING OCCURS AS THE UPPER TROF MOVES SLOWLY EASTWARD
DURING THE NIGHT. EVEN WITHOUT CONVECTIVE UPDRAFTS TE OVERALL DEEP
STRONG UPWARD LIFT AS THE MAIN SYSTEM APPROACHES WILL LIKELY
SUPPORT PERIODS OF MODERATE RAIN.
THURSDAY AND FRIDAY...
BY THU MORNING THE UPPER LOW IS PROGGED TO STILL BE OVER THE MID
MO VALLEY WHILE THE ASSOCIATED SURFACE CIRCULATION IS OVER/NEAR
THE LOCAL FORECAST AREA. BY THIS TIME THE BETTER FORCING WILL HAVE
MOVED ON TO OVER WI AND THE WESTERN GREAT LAKES. WITH THE MID AND
UPPER LEVEL LOWS TO THE W AND ONLY GRADUALLY DRIFT E DURING THE
DAY TOMORROW THE THREAT OF ADDITIONAL SHOWERS WILL PERSIST INTO IF
OT THROUGH THU NIGHT BEFORE THE UPPER SYSTEM STARTS TO PULL SLOWLY
AWAY TO THE NE. WHILE MUCH OF THE SOUTHERN AND EASTERN PORTIONS OF
THE FA MAY BRIEFLY GET INTO THE WARM SECTOR AS THE LOW MOVES
ACROSS THE AREA ONCE IT DOES LOW LEVEL COLD AIR ADVECTION GETS
ESTABLISHED AS THE VERY COOL AIR CURRENTLY OVER THE UPPER MIDWEST
AND THE WESTERN GREAT LAKES GETS WRAPPED AROUND THE DEPARTING
SURFACE LOW. OVERNIGHT LOWS THU NIGHT/FRI MORNING LOOK TO BE QUITE
COOL WITH 30S ACROSS THE AREA...AND POSSIBLY GETTING DOWN TO
FREEZING IN THE NORTH CENTRAL WESTERN PART OF THE FA. SOME LIGHT
SHOWERS CANNOT BE RULED OUT WITH COLD CYCLONIC FLOW STILL OVER THE
REGION INTO FRI AS THE UPPER LOW IS VERY SLOW TO MOVE OFF TO THE
NE. THERE MAY EVEN BE SOME LIGHT SNOW SHOWERS DURING THE LATE THU
NIGHT INTO FRI DUE TO THE RELUCTANCE OF THE LOW AND ITS COLD
CYCLONIC LOW IS VERY RELUCTANT TO SPEED AWAY. WITH COLD AIR STILL
IN PLACE AND MOSTLY CLOUDY SKIES FRI MAX TEMPS ARE ONLY EXPECTED
TO BE IN THE LOWER AND MID 40S...WITH SOME UPPER 40S IN THE S
COUNTIES OF THE FA.
SAT AND SUN...
COOL CONDITIONS TO PERSIST SAT AS WE REMAIN UNDER NW FLOW THEN
MODERATING TEMPS FOR SUN AS THE OLD UPPER LOW FINALLY MOVES ACROSS
QUEBEC AND THE FLOW BACKS TO WSW. HOWEVER...ANOTHER UPPER
DISTURBANCE IS PROGGED TO BE MOVING EASTWARD FROM THE NORTHERN
ROCKIES AND NORTHERN HIGH PLAINS. RETURN FLOW WILL BE
INCREASING...RESULTING IN THE MODERATION IN TEMPS...BUT WILL ALSO
BE DRAWING GULF MOISTURE NORTHWARD WITH A THREAT OF RAIN.
TRS
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 06Z...
* RAIN/ISOLATED TSRA ENDING BY 07Z.
* STRONG/GUSTY EASTERLY WINDS THIS MORNING...WITH A BRIEF PERIOD
OF STRONGER WINDS AFTER RAIN ENDS WITH GUSTS POSSIBLY AS HIGH AS
35 KTS.
* IFR CIGS INTO THIS AFTERNOON AND POSSIBLE AGAIN TONIGHT. LIFR
POSSIBLE AROUND SUNRISE.
* SHOWERS MID/LATE MORNING. CMS
//DISCUSSION...UPDATED 06Z...
BACK EDGE OF THE RAIN MAKING STEADY PROGRESS EASTWARD AND WILL
CLEAR CHICAGO AREA AROUND 07Z. COULD STILL BE SOME ISOLATED
THUNDER BEFORE THE RAIN ENDS...BUT THE STRONGEST STORMS AND THE
BULK THE LIGHTNING HAVE SHIFTED EAST. EXPECT AT LEAST A FEW HOURS
OF DRY WEATHER BEFORE ANOTHER WEAK WAVE ROTATES ACROSS THE AREA
LATER THIS MORNING...WHICH SHOULD PRODUCE AT LEAST SCATTERED
SHOWERS.
EASTERLY WINDS WILL REMAIN STRONG/GUSTY THROUGH SUNRISE AND BEGIN
TO SLOWLY DIMINISH LATER THIS MORNING AS SURFACE LOW PRESSURE
MOVES NORTH AND ELONGATES ACROSS THE REGION. BRIEF PERIOD OF
STRONGER WINDS OCCURRING...JUST BEHIND THE BACK EDGE OF THE
PRECIP WITH SQI AS HIGH AS 42KTS RECENTLY. THESE STRONGER WINDS
LIKELY ASSOCIATED WITH A WAKE LOW AND HAVE COVERED THESE STRONGER
WINDS WITH A TEMPO FOR NOW...THOUGH CONFIDENCE IS LOW REGARDING
SPECIFIC STRENGTHEN AND DURATION. WINDS WILL EVENTUALLY BECOME
SOUTH/SOUTHWEST LATER THIS AFTERNOON INTO THIS EVENING AS THE
SURFACE LOW DRIFTS NORTH...BUT SOME REFINEMENT WILL LIKELY BE
NEEDED WITH LATER FORECASTS FOR TIMING.
IFR CIGS WILL CONTINUE INTO THE MORNING HOURS AND LIFR CIGS MAY
DEVELOP AS THE LOW MOVES ACROSS THE AREA. AS THE LOW DRIFTS NORTH
LATER THIS AFTERNOON INTO THIS EVENING...EXPECT SOME IMPROVEMENT
WITH CIGS POSSIBLY LIFTING TO LOW MVFR. AS COLDER AIR SPREAD BACK
ACROSS THE REGION LATER TONIGHT...CIGS MAY DROP BACK TO IFR. CMS
//ORD AND MDW CONFIDENCE...UPDATED 06Z...
* HIGH CONFIDENCE FOR PRECIP ENDING BY 07Z...MEDIUM CONFIDENCE FOR
SHOWERS LATER THIS MORNING.
* HIGH CONFIDENCE REGARDING WINDS/SPEEDS/GUSTS THROUGH MID MORNING
THEN LOW CONFIDENCE FOR THE REST OF THE PERIOD.
* HIGH CONFIDENCE FOR IFR CIGS THROUGH MID MORNING...LOW
CONFIDENCE REGARDING CIG TRENDS THIS AFTERNOON INTO THIS
EVENING. CMS
//OUTLOOK FOR ORD/MDW FOR 12Z FRIDAY-12Z WEDNESDAY...UPDATED 00Z...
FRIDAY...CHANCE OF RAIN/SNOW SHOWERS. MVFR POSSIBLE.
SATURDAY...VFR.
SUNDAY THROUGH TUESDAY...PERIODIC CHANCES OF RAIN. OCCASIONAL MVFR
CONDITIONS POSSIBLE.
RATZER
&&
.MARINE...
300PM...A STRONG PRESSURE GRADIENT REMAINS IN PLACE OVER LAKE
MICHIGAN...BETWEEN STRONG HIGH PRESSURE OVER SOUTHEASTERN CANADA
AND A TROUGH OF LOW PRESSURE AND AN ASSOCIATED QUASI-STATIONARY
WARM FRONT EXTENDING EAST THROUGH CENTRAL ILLINOIS AND
INDIANA. NORTHEAST TO EAST GALES WILL PERSIST OVER ALL OF THE OPEN
WATERS THROUGH THE DAY TOMORROW. THE INITIAL LOW WILL LIFT
NORTHEAST TO NORTHERN INDIANA TOMORROW AS A SECONDARY LOW DEVELOPS
OVER IOWA. AN OCCLUDED FRONT CONNECTING THE TWO LOWS WILL LIFT
NORTHWARD UP THE LENGTH OF LAKE MICHIGAN TOMORROW EVENING AND INTO
FRIDAY...FINALLY REACHING THE NORTHERN END OF THE LAKE BY FRIDAY
AFTERNOON. WINDS WILL SUBSIDE BELOW GALE FORCE AS THE OCCLUDED
FRONT LIFTS NORTHWARD UP THE LAKE WITH WIND DIRECTION SHIFTING TO
NORTHWESTERLY AND THEN WESTERLY. THE MAIN LOW WILL THEN LIFT
NORTHEASTWARD INTO SOUTHEASTERN CANADA FRIDAY NIGHT AS HIGH
PRESSURE BUILDS ACROSS THE CENTRAL PLAINS. THE HIGH WILL SPREAD
EAST ACROSS LAKE MICHIGAN SATURDAY LEADING TO A BRIEF PERIOD OF
RELATIVELY LIGHT WINDS. AS THE HIGH PUSHES EAST OF THE LAKE BY
SUNDAY...NEW LOW PRESSURE WILL DEVELOP OVER THE CENTRAL
PLAINS...BRINGING INCREASING SOUTHEASTERLY TO SOUTHERLY WINDS TO
THE LAKE.
KREIN
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...GALE WARNING...NEARSHORE WINTHROP HARBOR TO NORTHERLY IS UNTIL 10
AM THURSDAY.
SMALL CRAFT ADVISORY...LMZ740-LMZ741...10 AM THURSDAY TO 11 PM
FRIDAY.
GALE WARNING...LMZ080-LMZ366-LMZ565-LMZ567-LMZ669-LMZ671-LMZ673-
LMZ675-LMZ777-LMZ779-LMZ868-LMZ870-LMZ872-LMZ874-LMZ876-
LMZ878 UNTIL 9 PM THURSDAY.
GALE WARNING...LMZ261-LMZ362-LMZ364-LMZ563 UNTIL 10 AM FRIDAY.
SMALL CRAFT ADVISORY...LMZ742 UNTIL 11 PM FRIDAY.
SMALL CRAFT ADVISORY...INDIANA NEARSHORE WATERS UNTIL 5 AM SATURDAY.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1204 AM CDT THU APR 11 2013
.DISCUSSION...
ISSUED 930 PM CDT WED APR 10 2013
MCS CLUSTER CONTINUES TO PUSH ACROSS ILLINOIS SOUTHWARD TO NEAR
MEMPHIS...WITH THE CORE OF THE LINE ABOUT HALFWAY ACROSS THE ILX
FORECAST AREA. SURFACE OBS SHOWING A COUPLE LOWS...ONE JUST WEST
OF EFFINGHAM WHICH MAY BE MORE OF A MESO-LOW...AND THE PRIMARY LOW
JUST WEST OF ST LOUIS. ASSOCIATED SURFACE BOUNDARY WAS ROUGHLY
ALONG I-70 AT 9 PM...WHICH THE MODELS HAVE BEEN STRUGGLING WITH
ITS PLACEMENT UNTIL RECENTLY. HOWEVER...THE LATEST RAP MODEL HAS A
BETTER HANDLE ON IT...AND IS SHOWING A NORTHWARD BULGE BACK TOWARD
CHAMPAIGN AND DANVILLE BY AROUND MIDNIGHT AS THE MAIN LOW MOVES
INTO CENTRAL ILLINOIS. CONTINUING SEVERE THREAT ACROSS AREAS
MAINLY EAST OF I-55 FOR THE NEXT 3 TO 4 HOURS OR SO...THEN RAIN
WILL BE TAPERING FROM THE WEST AFTER MIDNIGHT. TEMPERATURES WILL
STILL BE A CHALLENGE WITH THE SIGNIFICANT TEMPERATURE SHIFTS ALONG
OUR CURRENT BOUNDARY AND THE INCOMING COLD FRONT...BUT THE
SOUTHEAST CWA IS MOST LIKELY TO REMAIN IN THE WARM SECTOR MOST OF
THE NIGHT.
GEELHART
&&
.AVIATION...
ISSUED 1200 PM CDT WED APR 10 2013
MAIN FORECAST CONCERN NOW WILL BE DURATION OF MVFR AND LOCAL IFR
CONDITIONS AS SLOW MOVING UPPER LOW TO OUR WEST TRACKS INTO THE
NORTHERN PLAINS. LARGE AREA OF MVFR CIGS NOTED ON THE SATELLITE
AND SURFACE OBSERVATIONS SO WILL CONTINUE FROM PREVIOUS TRENDS IN
HOLDING MOST AREAS DOWN TO MVFR WITH OCCASIONAL CIGS DROPPING TO
IFR OVERNIGHT AND DURING THE MORNING HOURS OF THURSDAY. WE SHOULD
SEE A GRADUAL INCREASE IN CIGS TO BETWEEN 1200 TO 2000 FEET DURING
THE AFTERNOON BUT DON`T SEE MUCH HOPE FOR ANY WIDESPREAD DECREASE
IN CLOUD COVER AS OUR FLOW WILL REMAIN CYCLONIC INTO THE EVENING
HOURS. WINDS WILL START OUT FROM AN EASTERLY DIRECTION BUT AS THE
SFC LOW PUSHES OFF TO OUR NORTH...EXPECT WINDS TO TURN MORE INTO
A SOUTHWEST TO WEST DIRECTION BY TOMORROW AFTERNOON. WIND SPEEDS
WILL RANGE FROM 10 TO 15 KTS WITH A FEW GUSTS AROUND 20 KTS EARLY
THIS MORNING.
SMITH
&&
.PREV DISCUSSION...
ISSUED 316 PM CDT WED APR 10 2013
ACTIVE WEATHER ONGOING WITH STRONG STORMS IN EXTREME EASTERN IL
AND THUNDERSTORMS IN WEST CENTRAL IL. THE BIGGEST QUESTION FOR
THIS EVENING AND TONIGHT WILL BE THE MOVEMENT OF LOW PRESSURE WEST
OF STL AND THE ASSOCIATED BOUNDARY THAT MOVED THROUGH MUCH OF
CENTRAL IL AND PARTS OF EAST CENTRAL IL THIS MORNING.
TEMPERATURES WILL BE ALL OVER THE PLACE THE NEXT SEVEN DAYS AS
COLDER AIR MOVES IN THE NEXT FEW DAYS...FOLLOWED BY A WARM UP
LATER IN THE WEEK AND THEN A POTENTIAL COOL DOWN AGAIN BY MIDWEEK.
ANOTHER UPPER LEVEL SYSTEM AND ASSOCIATED LOW AND COLD
FRONT...SIMILAR TO THE ONE WE ARE EXPERIENCING TONIGHT-FRIDAY...
IS EXPECTED FROM ABOUT TUESDAY THROUGH MIDWEEK.
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
THERE IS QUITE A BIT OF UNCERTAINTY AS TO THE TRACK OF THE
AFOREMENTIONED SURFACE LOW TONIGHT...WHICH WILL MAKE A HUGE
DIFFERENCE IN TEMPERATURES AND POTENTIAL FOR STRONG/SVR STORMS. AT
THIS POINT IT LOOKS LIKE THE NAM AND LOCAL WRF HAVE THE PREFERRED
SOLUTION WITH THE FRONT CREEPING A LITTLE BIT TO THE NORTH AND THE
LOW TRACKING REAL CLOSE TO SPI AFTER MIDNIGHT AND JUST NORTH OF
CMI-DNV BY DAYBREAK. THIS WOULD KEEP THE BIGGEST THREAT FOR
STRONG/SVR STORMS ROUGHLY ALONG AND EAST OF I-55.
THURSDAY MORNING THE COLD FRONT IS EXPECTED TO BE NEAR THE INDIANA
BORDER...SO WILL KEEP THE MENTION OF T-STORMS GOING IN THE MORNING
IN EASTERN IL...WITH A CHANCE FOR SHOWERS IN WEST CENTRAL IL AND
EAST OF A PIA-DEC-EFFINGHAM LINE THROUGH EARLY EVENING IN THE LOW
LEVEL CYCLONIC FLOW AND SHORTWAVE LIFTING THROUGH THE UPPER
MIDWEST.
CYCLONIC FLOW IS EXPECTED TO REMAIN OVER MUCH OF THE AREA UNTIL
EARLY SATURDAY KEEPING CLOUDS AND COOL TEMPERATURES OVER CENTRAL
AND EASTERN IL. COULD SEE A FEW LIGHT SHOWERS NORTH OF A GBG-PIA-
BMI LINE FRIDAY...OTHERWISE THE REST OF THE FORECAST AREA WILL BE DRY.
LONG TERM...SATURDAY THROUGH WEDNESDAY
HIGH PRESSURE ON SATURDAY WILL GIVE US A BRIEF BREAK IN THE
RAINFALL. HOWEVER...INCREASING WARM ADVECTION IN THE LOW AND MID
LEVELS AND A ZONAL UPPER LEVEL FLOW WILL BRING A RETURN TO SHOWERS
SATURDAY NIGHT...WITH A FEW THUNDERSTORMS POSSIBLE TOWARD SUNDAY
MORNING.
BY EARLY NEXT WEEK OUR UPPER LEVEL PATTERN WILL BACK TO A
SOUTHWEST FLOW AS ANOTHER UPPER LEVEL LOW IS EXPECTED TO DIG INTO
THE SOUTHWESTERN STATES. THE GFS AND EUROPEAN ARE ACTUALLY FAIRLY
SIMILAR IN DEPICTING THIS SCENARIO...ALTHOUGH THE EURO IS A BIT
MORE AMPLIFIED.
THE BIG QUESTION FOR MONDAY THROUGH WEDNESDAY IS WHERE WILL A
NEARLY STATIONARY FRONT SET UP. BOTH THE GFS AND EUROPEAN INDICATE
THAT THE FRONT WILL SETTLE INTO CENTRAL IL MONDAY MORNING AND
REMAIN OVER THE AREA UNTIL AT LEAST TUESDAY. THE GFS IS QUICKER
BRINGING OUT AN AREA OF LOW PRESSURE LATER TUESDAY...WHILE THE
EURO HOLDS OFF UNTIL WEDNESDAY. THE BOTTOM LINE FOR NOW IS THAT
DUE TO THE FRONT IN THE VICINITY WILL NEED TO KEEP AN EXTENDED
PERIOD OF CHANCE POPS IN THE FORECAST FOR MONDAY THROUGH WEDNESDAY.
MILLER
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1209 AM CDT THU APR 11 2013
.UPDATE...
ISSUED AT 959 PM CDT WED APR 10 2013
HAVE UPDATED FORECAST TO REDUCE WINTER IMPACTS OF THE SYSTEM.
EXTRAPOLATION OF CURRENT PRECIP SHIELD SUGGESTS SRN BACK EDGE WILL
LIFT INTO MN 09-12Z...WHICH HAS BEEN SUPPORTED BY RECENT HRRR RUNS
WHICH SEEM TO BE HANDLING REALITY WELL. TEMPS ARE STILL AS WARM AS
36F AS FAR NORTH AS FORT DODGE...ALGONA...FOREST CITY AND IOWA
FALLS AND DUAL POL CC PRODUCTS ARE INDICATING PLENTY OF MIXED
PHASE PRECIP SUGGESTING IT WILL BE DIFFICULT TO GET MUCH SNOW
ACCUMS GOING ANYTIME SOON. ROAD SURFACE TEMPS TO THE MN BORDER ARE STILL
JUST ABOVE FREEZING AS WELL. MODELS ARE IN GOOD AGREEMENT
INCREASING VERTICAL MOTION FAIRLY SOON...SO CONFIDENCE IN LOWER
AMOUNTS IS NOT EXTREMELY HIGH...BUT FELT A DOWNWARD TREND WAS
STILL JUSTIFIED. COULD NOT SEE SNOW RATES MATERIALIZE IN TIME TO
REACH PREVIOUSLY ANTICIPATED AMOUNTS.
&&
.SHORT TERM.../TONIGHT /
ISSUED AT 421 PM CDT WED APR 10 2013
SURFACE LOW WILL CONTINUE TO TRACK SLOWLY EAST NORTHEAST FROM
CENTRAL MISSOURI INTO NORTHERN ILLINOIS BY 12Z THURSDAY. MODELS
REMAIN IN GOOD AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN...BUT
NAM DRIES OUT THE UPPER LEVELS PAST 06Z THURSDAY IN NORTHERN IOWA
RESULTING IN LESSER SNOW AMOUNTS. LEANED TOWARD A SREF/GFS BLEND.
LARGE SWATH OF THETA-E ADVECTION WILL CONTINUE TO BRING WIDESPREAD
LIGHT TO MODERATE RAIN THIS EVENING OVER CENTRAL AND SOUTHERN
PORTIONS OF THE STATE. DRY SLOT BEGINS TO PUNCH INTO THE SOUTH
CENTRAL PORTION OF THE FORECAST AREA LATE THIS EVENING AND HAVE
DECREASED POPS IN THIS LOCATION. OTHERWISE...HIGHEST POPS NORTH OF
I-80 AS THE BEST FORCING AND THETA-E ADVECTION WILL PERSIST THROUGH
TOMORROW MORNING. NAM BUFR SOUNDINGS AT MCW TO ALO DEPICT THEY LOSE
ICE INTRODUCTION PAST 06Z THURSDAY...WHILE THE GFS KEEPS THE DEEPER
MOISTURE GOING OVERNIGHT. LEANED TOWARD THE GFS SOLUTION AS GOOD
THETA-E ADVECTION AND MOISTURE TRANSPORT PERSISTS ALONG THE 290K TO
305K ISENTROPIC SURFACE ACROSS FAR NORTHERN IOWA. TEMPERATURES LOOK
TO REMAIN NEAR FREEZING ACROSS THE NORTHEAST AND MAY SEE SOME FZRA
THIS EVENING BEFORE THE SWITCH OCCURS PAST MIDNIGHT. FURTHER
WEST...DENISON TO CARROLL TO FORT DODGE WILL SEE PRECIP SWITCHING
BACK AND FORTH FROM FZRA AND SNOW...POSSIBLY EVEN SOME SLEET AT
TIMES. AS A RESULT...LEANED TOWARD A WINTER WEATHER ADVISORY
FURTHER SOUTH WITH THE WINTRY MIX TONIGHT INTO THURSDAY MORNING.
NO MAJOR CHANGES WITH THE ONGOING SNOW FORECAST FOR THE FAR
NORTHWEST PORTIONS OF THE FORECAST AREA.
.LONG TERM.../THURSDAY THROUGH WEDNESDAY/
ISSUED AT 421 PM CDT WED APR 10 2013
THE MID LEVEL DRY SLOT WILL HAVE LIFTED OVER MUCH OF CENTRAL IOWA
BY THURSDAY MORNING AND THIS WILL BRING RESULT IN A LOSS OF ICE
INTRODUCTION. POSSIBLE THIS WILL LEAD TO FREEZING DRIZZLE OVER THE
FAR NORTH YET THROUGH THE MORNING WHERE SFC TEMPERATURES REMAIN AT
OR BELOW FREEZING. GIVEN THE TIME OF YEAR...ENOUGH RADIATION
SHOULD MAKE IT THROUGH THE CLOUD TO HEAT TEMPERATURES ENOUGH TO
RISE ABOVE FREEZING OVER THE NORTH AND ELIMINATE THE FREEZING RAIN
POTENTIAL. COOLING THROUGH THE COLUMN WILL ERODE THE REMAINING
WARM LAYER OVER HEADLINE REGION WITH THE POTENTIAL CHANGING TO
RAIN OR SNOW AS THE NEXT SHORT WAVE WRAPS AROUND FROM THE WEST AND
BRINGING A RETURN TO ICE INTRODUCTION. THE PRECIPITATION WILL
GRADUALLY END AS SNOW OVER THE NORTHEAST THURSDAY NIGHT AND EARLY
FRIDAY WITH ONLY MINOR ACCUMULATIONS EXPECTED. KEPT HIGH
TEMPERATURES ON THURSDAY BELOW GUIDANCE WHICH ARE PRODUCING TOO
STEEP OF LOW LEVEL LAPSE RATES WITH THE GIVEN CLOUD COVER. A BLEND
OF RAW TEMPERATURES IS A BETTER FIT
COLD CONDITIONS WILL CONTINUE ON FRIDAY WITH BREEZY NORTHWEST
WINDS AND THE 850 MB THERMAL TROUGH EXTENDING INTO THE STATE. THE
MID LEVEL FLOW BECOMES MORE ZONAL ON SATURDAY AND AFTER A COOL
START...TEMPERATURES WILL WARM TO AROUND 10 DEGREES WARMER THAN
FRIDAY THOUGH STILL WELL BELOW SEASONAL AVERAGES. PRECIPITATION
CHANCES RETURN SATURDAY NIGHT WITH STRONG THETA-E ADVECTION
LIFTING INTO THE REGION. LOW PRESSURE MOVING THROUGH ON SUNDAY
WILL KEEP CHANCES GOING WITH THE POTENTIAL FOR SHOWERS AND
ISOLATED THUNDERSTORMS. ANOTHER LONG WAVE TROUGH WILL DEVELOP OVER
THE WESTERN CONUS THROUGH EARLY TO MID NEXT WEEK AND WILL KEEP THE
STATE IN AN ACTIVE PATTERN. THE 850 MB THERMAL GRADIENT WILL
REMAIN NEARBY THROUGH THE PERIOD THEN GRADUALLY SINK INTO THE AREA
TUESDAY INTO WEDNESDAY. MUCH OF THE PRECIPITATION WILL FALL IN
THE FORM OF RAIN THOUGH THE ARRIVAL OF THE COLDER AIR COULD BRING A
MIX OF SNOW ONCE AGAIN OVER THE NORTH.
&&
.AVIATION...11/06Z
ISSUED AT 1208 AM CDT THU APR 11 2013
WIDESPREAD IFR CONDITIONS EXIST ACROSS THE FORECAST AREA LATE THIS
EVENING AND LITTLE CHANGE IN CATEGORY IS ANTICIPATED INTO THE
NIGHT. A FEW SPOTS MAY BRIEFLY BUMP UP TO MVFR BUT THAT WOULD NOT
LAST LONG. AREA OF SOMEWHAT HEAVIER PRECIPITATION WILL CONTINUE
LIFTING NORTHWARD...MAINLY AFFECTING WRN HALF OF IA WITH
PREDOMINATELY RAIN. MAY SEE A SMALL WINDOW OF LIGHT FREEZING
PRECIP AT MCW HOWEVER. MUCH OF THE HEAVIER PRECIP SHOULD EXIT IA
INTO MN BY 11-12Z LEAVING BEHIND DRIZZLE AND STRATUS...STILL IFR
OR POSSIBLE LOW END MVFR BY AFTERNOON. IFR/MVFR CIGS WILL REMAIN
IN PLACE INTO WED EVENING AS WELL...POSSIBLY WITH SOME LIGHT SNOW
BY THAT TIME.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THIS AFTERNOON FOR
CALHOUN-CERRO GORDO-CRAWFORD-HANCOCK-HUMBOLDT-POCAHONTAS-SAC-
WORTH.
WINTER STORM WARNING UNTIL 1 PM CDT THIS AFTERNOON FOR EMMET-
KOSSUTH-PALO ALTO-WINNEBAGO.
&&
$$
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
UPDATE/AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1000 PM CDT WED APR 10 2013
.UPDATE...
ISSUED AT 959 PM CDT WED APR 10 2013
HAVE UPDATED FORECAST TO REDUCE WINTER IMPACTS OF THE SYSTEM.
EXTRAPOLATION OF CURRENT PRECIP SHIELD SUGGESTS SRN BACK EDGE WILL
LIFT INTO MN 09-12Z...WHICH HAS BEEN SUPPORTED BY RECENT HRRR RUNS
WHICH SEEM TO BE HANDLING REALITY WELL. TEMPS ARE STILL AS WARM AS
36F AS FAR NORTH AS FORT DODGE...ALGONA...FOREST CITY AND IOWA
FALLS AND DUAL POL CC PRODUCTS ARE INDICATING PLENTY OF MIXED
PHASE PRECIP SUGGESTING IT WILL BE DIFFICULT TO GET MUCH SNOW
ACCUMS GOING ANYTIME SOON. ROAD SURFACE TEMPS TO THE MN BORDER ARE STILL
JUST ABOVE FREEZING AS WELL. MODELS ARE IN GOOD AGREEMENT
INCREASING VERTICAL MOTION FAIRLY SOON...SO CONFIDENCE IN LOWER
AMOUNTS IS NOT EXTREMELY HIGH...BUT FELT A DOWNWARD TREND WAS
STILL JUSTIFIED. COULD NOT SEE SNOW RATES MATERIALIZE IN TIME TO
REACH PREVIOUSLY ANTICIPATED AMOUNTS.
&&
.SHORT TERM.../TONIGHT /
ISSUED AT 421 PM CDT WED APR 10 2013
SURFACE LOW WILL CONTINUE TO TRACK SLOWLY EAST NORTHEAST FROM
CENTRAL MISSOURI INTO NORTHERN ILLINOIS BY 12Z THURSDAY. MODELS
REMAIN IN GOOD AGREEMENT WITH THE OVERALL SYNOPTIC PATTERN...BUT
NAM DRIES OUT THE UPPER LEVELS PAST 06Z THURSDAY IN NORTHERN IOWA
RESULTING IN LESSER SNOW AMOUNTS. LEANED TOWARD A SREF/GFS BLEND.
LARGE SWATH OF THETA-E ADVECTION WILL CONTINUE TO BRING WIDESPREAD
LIGHT TO MODERATE RAIN THIS EVENING OVER CENTRAL AND SOUTHERN
PORTIONS OF THE STATE. DRY SLOT BEGINS TO PUNCH INTO THE SOUTH
CENTRAL PORTION OF THE FORECAST AREA LATE THIS EVENING AND HAVE
DECREASED POPS IN THIS LOCATION. OTHERWISE...HIGHEST POPS NORTH OF
I-80 AS THE BEST FORCING AND THETA-E ADVECTION WILL PERSIST THROUGH
TOMORROW MORNING. NAM BUFR SOUNDINGS AT MCW TO ALO DEPICT THEY LOSE
ICE INTRODUCTION PAST 06Z THURSDAY...WHILE THE GFS KEEPS THE DEEPER
MOISTURE GOING OVERNIGHT. LEANED TOWARD THE GFS SOLUTION AS GOOD
THETA-E ADVECTION AND MOISTURE TRANSPORT PERSISTS ALONG THE 290K TO
305K ISENTROPIC SURFACE ACROSS FAR NORTHERN IOWA. TEMPERATURES LOOK
TO REMAIN NEAR FREEZING ACROSS THE NORTHEAST AND MAY SEE SOME FZRA
THIS EVENING BEFORE THE SWITCH OCCURS PAST MIDNIGHT. FURTHER
WEST...DENISON TO CARROLL TO FORT DODGE WILL SEE PRECIP SWITCHING
BACK AND FORTH FROM FZRA AND SNOW...POSSIBLY EVEN SOME SLEET AT
TIMES. AS A RESULT...LEANED TOWARD A WINTER WEATHER ADVISORY
FURTHER SOUTH WITH THE WINTRY MIX TONIGHT INTO THURSDAY MORNING.
NO MAJOR CHANGES WITH THE ONGOING SNOW FORECAST FOR THE FAR
NORTHWEST PORTIONS OF THE FORECAST AREA.
.LONG TERM.../THURSDAY THROUGH WEDNESDAY/
ISSUED AT 421 PM CDT WED APR 10 2013
THE MID LEVEL DRY SLOT WILL HAVE LIFTED OVER MUCH OF CENTRAL IOWA
BY THURSDAY MORNING AND THIS WILL BRING RESULT IN A LOSS OF ICE
INTRODUCTION. POSSIBLE THIS WILL LEAD TO FREEZING DRIZZLE OVER THE
FAR NORTH YET THROUGH THE MORNING WHERE SFC TEMPERATURES REMAIN AT
OR BELOW FREEZING. GIVEN THE TIME OF YEAR...ENOUGH RADIATION
SHOULD MAKE IT THROUGH THE CLOUD TO HEAT TEMPERATURES ENOUGH TO
RISE ABOVE FREEZING OVER THE NORTH AND ELIMINATE THE FREEZING RAIN
POTENTIAL. COOLING THROUGH THE COLUMN WILL ERODE THE REMAINING
WARM LAYER OVER HEADLINE REGION WITH THE POTENTIAL CHANGING TO
RAIN OR SNOW AS THE NEXT SHORT WAVE WRAPS AROUND FROM THE WEST AND
BRINGING A RETURN TO ICE INTRODUCTION. THE PRECIPITATION WILL
GRADUALLY END AS SNOW OVER THE NORTHEAST THURSDAY NIGHT AND EARLY
FRIDAY WITH ONLY MINOR ACCUMULATIONS EXPECTED. KEPT HIGH
TEMPERATURES ON THURSDAY BELOW GUIDANCE WHICH ARE PRODUCING TOO
STEEP OF LOW LEVEL LAPSE RATES WITH THE GIVEN CLOUD COVER. A BLEND
OF RAW TEMPERATURES IS A BETTER FIT
COLD CONDITIONS WILL CONTINUE ON FRIDAY WITH BREEZY NORTHWEST
WINDS AND THE 850 MB THERMAL TROUGH EXTENDING INTO THE STATE. THE
MID LEVEL FLOW BECOMES MORE ZONAL ON SATURDAY AND AFTER A COOL
START...TEMPERATURES WILL WARM TO AROUND 10 DEGREES WARMER THAN
FRIDAY THOUGH STILL WELL BELOW SEASONAL AVERAGES. PRECIPITATION
CHANCES RETURN SATURDAY NIGHT WITH STRONG THETA-E ADVECTION
LIFTING INTO THE REGION. LOW PRESSURE MOVING THROUGH ON SUNDAY
WILL KEEP CHANCES GOING WITH THE POTENTIAL FOR SHOWERS AND
ISOLATED THUNDERSTORMS. ANOTHER LONG WAVE TROUGH WILL DEVELOP OVER
THE WESTERN CONUS THROUGH EARLY TO MID NEXT WEEK AND WILL KEEP THE
STATE IN AN ACTIVE PATTERN. THE 850 MB THERMAL GRADIENT WILL
REMAIN NEARBY THROUGH THE PERIOD THEN GRADUALLY SINK INTO THE AREA
TUESDAY INTO WEDNESDAY. MUCH OF THE PRECIPITATION WILL FALL IN
THE FORM OF RAIN THOUGH THE ARRIVAL OF THE COLDER AIR COULD BRING A
MIX OF SNOW ONCE AGAIN OVER THE NORTH.
&&
.AVIATION...11/00Z
ISSUED AT 659 PM CDT WED APR 10 2013
WIDESPREAD IFR CONDITIONS EXIST ACROSS THE FORECAST AREA THIS
EVENING AND LITTLE CHANGE IN CATEGORY IS ANTICIPATED INTO THE
NIGHT. A FEW SPOTS MAY BRIEFLY BUMP UP TO MVFR BUT THAT WOULD NOT
LAST LONG. AREA OF PRECIPITATION WILL EXPAND AND LIFT NORTHWARD
ACROSS THE STATE. IT SHOULD MAINLY BE IN THE FORM OF
RAIN...ALTHOUGH NRN SITES COULD BRIEFLY MIX WITH SNOW OR FREEZING
RAIN EARLY THU MORNING. ALTHOUGH STRATUS WILL REMAIN IN
PLACE...THERE WILL LIKELY BE A BREAK IN PRECIP CENTRAL AND SOUTH THU
MORNING BEFORE CHANGES INCREASE AGAIN THU AFTERNOON.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THURSDAY FOR CALHOUN-
CERRO GORDO-CRAWFORD-HANCOCK-HUMBOLDT-POCAHONTAS-SAC-WORTH.
WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR EMMET-KOSSUTH-
PALO ALTO-WINNEBAGO.
&&
$$
UPDATE/AVATION...SMALL
SHORT TERM...PODRAZIK
LONG TERM...DONAVON
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1143 PM CDT Wed Apr 10 2013
...Updated for Aviation...
.UPDATE...
Issued at 900 PM CDT WED APR 10 2013
Widespread rains have shifted east of the CWA this evening, therefore
have cancelled flood watch. Weak shortwave energy rotating around the
trough will continue to produce a band of showers and moderate
drizzle as it pivots into the region. HRRR guidance seems to capture
ongoing trends well, with this band of showers pivoting into northern
Missouri and eventually Iowa by Midnight.
Otherwise remaining forecast remains on track as temperatures slowly
cool through the 30s overnight.
&&
.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 06Z TAFS through 06Z Thursday Night)
Issued at 1136 PM CDT WED APR 10 2013
Ceilings continue to bounce between MVFR/IFR for much of the evening
hours and this variability may continue through the remainder of the
overnight hours. Visibilities will be even more variable but should
remain between 3 and 6SM through daybreak...with very brief drops to
2SM or less.
For Thursday, conditions will slowly improve through the morning,
with ceilings lifting back toward VFR levels by mid afternoon. There
could be a few sprinkles or light showers along and north of Hwy 36
in the afternoon, but confidence too low to include in 06z TAFs.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
UPDATE...Dux
SHORT TERM...MJ
LONG TERM...Blair
AVIATION...Dux
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
327 AM EDT THU APR 11 2013
.SYNOPSIS...
UNSETTLED CONDITIONS WILL PREVAIL INTO SATURDAY AS A COMPLEX AREA OF LOW
PRESSURE MOVES FROM THE GREAT LAKES INTO THE NORTHEAST. SHOWERS...POSSIBLY
MIXED SLEET OVER PORTIONS OF CENTRAL NEW YORK...CAN BE EXPECTED
INTO FRIDAY...WITH SCATTERED RAIN OR SNOW SHOWERS PERSISTING INTO
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
NOT MUCH CHG FROM PREV FCST. INITIAL LOOK AT MDL GUIDANCE APPEARED
TO SHOW A COOL BIAS AT F06 W/RESPECT TO T/TD`S. GROUND TEMPS WILL
BE RELATIVELY WARM...AND WE DON`T SEE SFC TEMPS OR SFC WET
BULBS GETTING BLO 32F THIS MRNG...REDUCING OR ELIMINATING ANY
FZRA THREAT. THIS HAS BEEN REFLECTED IN THE LATEST WWD GUIDANCE
WHICH LOOKS GOOD FROM OUR PERSPECTIVE. POPS INCRSNG FROM SW TO NE
AS NXT BATCH OF SHRA MOVS BACK INTO THE RGN. KEPT POTNL FOR SOME
SLEET TO MIX IN WITH THE RAIN ACRS PORTIONS OF THE CNTRL SRN TIER
AND FINGER LAKES...AND NRN ONEIDA.
FVRBL JET CONFIGURATION TNGT WITH FCST AREA IN RR QUAD OF THE 250
MB JET...COUPLED WITH A 50 KT SRLY 850 JET. GOOD ISEN LIFT TNGT
INTO FRI AHEAD OF THE OCCLUDED FNT. COOLEST AIR WILL RESIDE ACRS
ERN ZONES...BUT MDLS AGAIN MAY BE OVERDONE WITH THE LOW LVL COOL
AIR. RETAINED POTNL FOR SOME SLEET FROM NRN ONEIDA INTO THE WRN
CATSKILLS. COULD GET FAIRLY GUSTY TNGT...SPCLY HIGHER ELEVATIONS...AS
SELY FLOW INCRS.
WE`LL PRBLY SEE A GOOD 3/4 TO ONE INCH OF RAIN THU NGT INTO
FRI. WE SHOULD BE ABLE TO HANDLE THESE AMTS...BUT A FEW MAIN STEM
POINTS MAY APRCH CAUTION STAGE.
LASTLY...CAN`T RULE OUT ISOLD TSRA THIS AFTN OR TNGT...SPCLY ACRS
PA...BUT WILL JUST GO WITH SHRA FOR NOW AND LET LATER UPDATES ADD
MENTION IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
OCCLUDED FNT PASSES ON FRI...WITH BATCH OF RAIN XPCTD TO MOV OUT
OF ERN ZONES FRI AFTN. MAIN UPR TROF REMAINS OVER THE
GTLAKES...AND S/WV`S EMBEDDED IN THE SWLY FLOW ACRS NY/PA COULD
TRIGGER SCT -SHRA...WITH POTNL FOR -SHSN LATER AT NGT. A WEAK WAVE
IS EXPECTED TO PASS FRI NGT...WITH A STRONGER S/WV ON SAT.
RETAINED CHC POPS MAINLY ACRS CNTRL NY AND NRN PA...WITH ONLY SLGT
CHC POPS FAR SE ZONES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US LIFTS EARLY IN
THE LONG TERM. NW FLOW CONTINUES SAT NGT TO SUN SO POSSIBLY
FLURRIES AND SPRINKLES. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR LATE SUNDAY BEFORE A WARM FRONT LIFTS NE WITH RAIN FOR THE
AREA STARTING SUN NGT. ONCE AGAIN THIS FRONT WILL STALL ACROSS THE
AREA UNTIL WED WHEN A COLD FRONT APPROACHES AHEAD OF A LARGE UL
TROF. MODELS MAY BE TOO FAST WITH THE COLD FRONT SO OFF AND ON
SHOWERS MOST LIKELY SCENARIO.
&&
.AVIATION /07Z THURSDAY THROUGH MONDAY/...
AVIATION FORECAST REMAINS DIFFICULT...DUE TO COMPLICATIONS OF
BATCHES OF SHOWERS MOVING ALONG A WAFFLING FRONTAL BOUNDARY IN OUR
VICINITY. QUIET AT THE MOMENT PRECIPITATION-WISE...BUT NEXT WAVE
OF SHOWERS WILL SKIM THROUGH BEGINNING AROUND 09Z IN
AVP...FOLLOWED BY REMAINDER OF TERMINALS LATER IN THE MORNING. LOW
LEVEL DRY AIR COURTESY OF VEERING LIGHT FLOW BETWEEN WAVES IS
SNEAKING INTO KSYR-KRME...LIFTING CIGS INTO MVFR OR EVEN VFR THERE
THIS MORNING. OTHER TERMINALS EXCEPT KAVP ARE IFR OR LIFR...THOUGH
NOMINAL IMPROVEMENTS MAY OCCUR TOWARDS DAWN AS VEERING FLOW ATTEMPTS
TO BRING DRY LOW LEVEL AIR.
ADDITIONAL WAVES WILL AFFECT THE REGION FROM MIDDAY THROUGH
EVENING...THE INDIVIDUAL TIMING OF WHICH IS CHALLENGING AND LOW
CONFIDENCE. THE ASSOCIATED NEARLY STATIONARY FRONT WILL THEN
ATTEMPT TO EDGE NORTHWARD WITH TIME...PERHAPS GIVING KAVP-KELM-
KBGM-KITH A RELATIVE BREAK RAIN-WISE THIS EVENING BEFORE COLD
FRONT OF THE SYSTEM APPROACHES AFTER 06Z FRIDAY...BUT POSITIONING
OF BOUNDARY WILL CONTINUE TO FAVOR RAIN THIS EVENING FOR KSYR-
KRME. SEVERAL TERMINALS WILL CONTINUE OR RETURN TO IFR CONDITIONS
THIS EVENING. WINDS THROUGH THE TAF PERIOD WILL BE LIGHT YET
VEERING WITH TIME...GENERALLY FROM A NORTHERLY DIRECTION TO AND
EASTERLY ONE...SEE TAFS FOR SPECIFICS.
.OUTLOOK...
LATE THU NIGHT TO FRI...MVFR WITH PDS OF IFR AS SHOWERY FRONT PASSES.
SAT AND SUN...VFR...PSBL MVFR IN MIXED SHWRS.
SUN NGT AND MON...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
LONG TERM...TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
218 AM EDT THU APR 11 2013
.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN IN OUR VICINITY THROUGH THURSDAY
NIGHT...WITH OCCASIONAL BATCHES OF RAIN MOVING WEST TO EAST ALONG
IT THROUGH OUR REGION. THERE IS ALSO A CHANCE OF SOME SPOTTY
FREEZING RAIN OVER HIGHER ELEVATIONS OF THE FINGER LAKES IN NEW
YORK. DRIER AIR WILL FINALLY MOVE IN...AFTER A SHOWERY COLD FRONT
PASSES FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
1020 PM UPDATE...
MAIN AREA OF RAIN NOW WORKING THROUGH THE TWIN TIERS AND MUCH OF
NORTHEASTERN PA AS SUCCESSIVE SHORTWAVE DISTURBANCES TRAVEL EAST
ALONG A STALLED FRONTAL BOUNDARY. LOOKING UPSTREAM...RAIN WILL
LIKELY COME TO AN END FOR A SHORT WHILE BETWEEN 4 AND 6Z...WITH
ADDITIONAL ACTIVITY THEN EXPECTED TO MOVE IN LATER ON AS THE EARLY
MORNING HRS PROGRESS. LATEST LOOK AT AVAILABLE ISENTROPIC FIELDS
SUGGEST NEUTRAL ISENTROPIC UPGLIDE WILL PERSIST THROUGH MUCH OF
THE OVERNIGHT HRS ACROSS CENTRAL AND NORTHERN ZONES...WITH ASCENT
THEN INCREASING ONCE AGAIN AFTER 12Z AS MAIN LOW-LEVEL JET AXIS
APPROACHES FROM THE WEST.
LATEST RUC MLCAPE PLAN VIEW MAPS SHOWING ANY LINGERING INSTABILITY
NOW CONFINED TO AREAS WELL SOUTH OF THE FCST AREA. DESPITE THIS
HOWEVER...SEVERAL INDIVIDUAL STRIKES STILL DETECTED AND THUS WILL
MAINTAIN THUNDER MENTION FOR A FEW MORE HRS ACROSS THE SOUTH. MAIN
CONCERN GOING INTO THU MORNING CONTINUES TO BE PROSPECTS FOR FZRA
AS HIGH PRESSURE SOUTH OF HUDSON BAY CONTINUES TO BUILD SOUTH WITH
TIME EARLY THU MORNING. AS IT STANDS RIGHT NOW...BEST PROSPECTS
WILL BE ACROSS THE CENTRAL FINGER AND NORTHERN SOUTHERN TIER
PORTIONS OF THE FCST AREA HOWEVER CONSIDERING THE AMOUNT OF LOW
STRATUS HANGING AROUND THIS EVENING COUPLED WITH THE FACT THAT
TEMPS WILL LIKELY START WARMING UP FAIRLY QUICKLY TOMORROW
MORNING...FEEL ANY ICING CONCERNS SHOULD BE KEPT TO MINIMUM.
730 PM UPDATE... A FAIRLY BUSY LATE AFTERNOON/EVENING FOR
EARLY APRIL STANDARDS CONTINUES THIS HR WITH THE NEXT MCS
APPROACHING FROM THE WEST. CONVECTION ASSOCIATED WITH THE FIRST
CLUSTER RESULTED IN WIDESPREAD WIND DAMAGE ACROSS THE LOWER
WYOMING VALLEY AND POCONOS WHERE NUMBERS REPORTS OF DOWN TREES
WERE RECEIVED. WITH THIS FEATURE GONE...ATTENTION IS QUICKLY DRAWN
BACK TO OUR WEST WITH LATEST RADAR TRENDS SHOWING AN ORGANIZED
LINE-ECHO WAVE PATTERN (LEWP) STRETCHING FROM JUST NORTH OF
PITTSBURGH NORTHEAST THROUGH CENTRAL PA AND EVENTUALLY THE CENTRAL
CENTRAL TWIN TIERS OF CENTRAL TWIN TIERS. MAIN CULPRIT CONTINUES
TO BE A SERIES OF SHORTWAVE DISTURBANCES TRAVELING ALONG A STALLED
FRONTAL BOUNDARY WHICH REMAINS POSITIONED OVER THE FAR SOUTHERN
PORTION OF THE FCST AREA THIS EVENING. WILL OBVIOUSLY HAVE TO
WATCH POTENTIAL FOR SEVERE THIS EVENING HOWEVER APPROACHING
ACTIVITY IS WORKING INTO A REGION THAT EXPERIENCED THIS
AFTERNOON/S EARLIER CONVECTION. THAT SAID...WE CURRENTLY EXPECT A
WEAKENING TREND WITH FURTHER EASTWARD PROGRESS HOWEVER CANNOT RULE
OUT THE NEED FOR A FEW ROGUE SPS STATEMENTS OR A WARNING OR TWO.
AFTER A FEW HRS...HIGH RES MODELS SHOW A GRADUAL SOUTHWARD SHIFT
TO ONGOING ACTIVITY AS FRONT SLOWLY SAGS SOUTH WITH TIME.
NORTHERLY FLOW WORKING SOUTH FROM NORTHERN NY AND SOUTHERN CANADA
WILL SET THE STAGE FOR COOLING TEMPS TOWARDS MORNING WHERE SOME
LIGHT FZRA WILL BE POSSIBLE ACROSS THE HIGHER ELEVATIONS OF THE
NORTHERN FINGER LAKES...SOUTHERN TUG HILL...AND UPPER SUSQUEHANNA
VALLEY REGIONS. WILL CONTINUE TO MONITOR.
PREVIOUS NEAR TERM DISCUSSION...
COMPLEX SCENARIO OVER THE FCST AREA WITH DFRNT DVLPG WX THREATS.
IN THE VERY NEAR TERM...LINE OF TRWS OVER WRN PA MARCHING EAST
WILL BRING CONV TO THE FCST AREA. ATTM...LOOKS AS THOUGH MORE
LIMITED AVBL CAPE SHD WEAKEN THE CELLS AND THEY MOVE EAST.
HWVR...ANY CELLS WILL NEED TO WATCHED FOR FOR SVR WIND. SPC CRNTLY
NOT XPCTG A WATCH FOR PA.
OTR CNCRN FOR THE OVRNGT IS THE PSBLTY SOME FRZG RAIN LATE. HPC
WWD GRAPHICS PAINT AN AREA OF A TENTH TO QUARTER INCH OF ICE OVER
THE FINGER LAKES. HWVR...HIGH CONFIDENCE TEMPS FCST DUE TO GOOD
AGREEMENT BETWEEN THE MAV AND MET BARELY GENERATES ANY TEMPS AT OR
BLO FRZG UNTIL VERY LATE. CORE OF THE COLD AIR IS OVER THE AREA
AFT SUNRISE TMRW...WHEN MID APRIL SUN WILL MAKE ICE FORMATION DFCLT.
HAVE ELECTED TO HOLD OFF ON ANY FLAGS FOR ICE ATTM DUE TO VERY LOW
CONFIDENCE AND CVRG.
FINAL CNCRN IS QPF AMTS. SOME CONCERN THAT ENUF RAIN COULD FALL TO
CAUSE FLOODING ISSUES. NAM WHICH HAD BEEN FCSTG THE MOST QPF HAS
SLOWLY BACKED OFF. PCPN HAS BEEN ORGANIZING IN CONV COMPLEXES AND
MVG QUICKLY. IT SEEMS AS THROUGH THE THREAT FOR WIDESPREAD FLOOD
ISSUES IS LOW FOR TNGT.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...
WV EXITS EARLY THU ALLOWING FOR MID LVL CONV AND A BLDG SFC HIPRES
ON THU. THIS BRINGS THE COLDEST AIR INTO THE AREA DURING THE MRNG
THU...BUT WITH APRIL SUN...HTG DESPITE THE CLDS SHD MINIMIZE THE
ICING THREAT. LTR IN THE DAY...NEXT WV APCHS AND BNDRY BEGINS TO
LIFT NWRD YET AGAIN...BRINGING AT LEAST THE SWRN PARTS OF THE FCST
AREA BACK INTO THE WRM SECTOR BY 12Z FRI. VIGOROUS UPR WV ALONG
WITH DVLPG LL CONV SHD GENERATE A GOOD SOAKING OF RAIN LATE THU
INTO FRI...WITH THE PSBLTY OF CONV.
DRY SLOT PUSHES THRU THE ENTIRE FCST AREA BY FRI AS THE UPR LOW
DRIFTS NORTH OF THE LAKES. HWVR...ENUF LL MOISTURE AND INSTABILITY
IN THE CAA FOR SOME SCT SHWRS THRU THE END OF THE PD. CAA CONTS
THRU THE END OF THE PD AS WELL WITH H8 TEMPS DROPPING TO NEAR -6C
BY 00Z SUN. SFC TEMPS DO NOT SUPPORT ANY SNOW...AT LEAST THRU THE
END OF THE SHRT TERM.
MEX/MAV GUID CONTD IN GOOD AGREEMENT UNTIL FRI WHEN THE MAV PUSHES
TEMPS HIGHER OF THE NE ZONES...WHILE THE MET KEEPS THE COLD AIR
LOCKED IN. CONTD WITH THE BLEND OF GUID THRU THE END OF THE PD AS
A COMPROMISE FOR THE END OF THE PD.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US LIFTS EARLY IN
THE LONG TERM. NW FLOW CONTINUES SAT NGT TO SUN SO POSSIBLY
FLURRIES AND SPRINKLES. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR LATE SUNDAY BEFORE A WARM FRONT LIFTS NE WITH RAIN FOR THE
AREA STARTING SUN NGT. ONCE AGAIN THIS FRONT WILL STALL ACROSS THE
AREA UNTIL WED WHEN A COLD FRONT APPROACHES AHEAD OF A LARGE UL
TROF. MODELS MAY BE TOO FAST WITH THE COLD FRONT SO OFF AND ON
SHOWERS MOST LIKELY SCENARIO.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AVIATION FORECAST REMAINS DIFFICULT...DUE TO COMPLICATIONS OF
BATCHES OF SHOWERS MOVING ALONG A WAFFLING FRONTAL BOUNDARY IN OUR
VICINITY. QUIET AT THE MOMENT PRECIPITATION-WISE...BUT NEXT WAVE
OF SHOWERS WILL SKIM THROUGH BEGINNING AROUND 09Z IN
AVP...FOLLOWED BY REMAINDER OF TERMINALS LATER IN THE MORNING. LOW
LEVEL DRY AIR COURTESY OF VEERING LIGHT FLOW BETWEEN WAVES IS
SNEAKING INTO KSYR-KRME...LIFTING CIGS INTO MVFR OR EVEN VFR THERE
THIS MORNING. OTHER TERMINALS EXCEPT KAVP ARE IFR OR LIFR...THOUGH
NOMINAL IMPROVEMENTS MAY OCCUR TOWARDS DAWN AS VEERING FLOW ATTEMPTS
TO BRING DRY LOW LEVEL AIR.
ADDITIONAL WAVES WILL AFFECT THE REGION FROM MIDDAY THROUGH
EVENING...THE INDIVIDUAL TIMING OF WHICH IS CHALLENGING AND LOW
CONFIDENCE. THE ASSOCIATED NEARLY STATIONARY FRONT WILL THEN
ATTEMPT TO EDGE NORTHWARD WITH TIME...PERHAPS GIVING KAVP-KELM-
KBGM-KITH A RELATIVE BREAK RAIN-WISE THIS EVENING BEFORE COLD
FRONT OF THE SYSTEM APPROACHES AFTER 06Z FRIDAY...BUT POSITIONING
OF BOUNDARY WILL CONTINUE TO FAVOR RAIN THIS EVENING FOR KSYR-
KRME. SEVERAL TERMINALS WILL CONTINUE OR RETURN TO IFR CONDITIONS
THIS EVENING. WINDS THROUGH THE TAF PERIOD WILL BE LIGHT YET
VEERING WITH TIME...GENERALLY FROM A NORTHERLY DIRECTION TO AND
EASTERLY ONE...SEE TAFS FOR SPECIFICS.
.OUTLOOK...
LATE THU NIGHT TO FRI...MVFR WITH PDS OF IFR AS SHOWERY FRONT PASSES.
SAT AND SUN...VFR...PSBL MVFR IN MIXED SHWRS.
SUN NGT AND MON...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM/MDP
NEAR TERM...CMG/DGM
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BISMARCK ND
103 AM CDT THU APR 11 2013
.UPDATE...
ISSUED AT 102 AM CDT THU APR 11 2013
LATEST RADAR REFLECTIVITY SHOWS SOME LIGHT RETURNS ADVECTING
NORTHWEST ACROSS THE JAMES RIVER BASIN EARLY THIS MORNING. SURFACE
OBSERVATIONS OVER THE LAST FEW HOURS SHOW THAT LIGHT SNOW WAS
REPORTED IN OAKES IN DICKEY COUNTY. BASED ON LATEST 04Z RAP AND
NAM...HAVE INCREASED POPS ACROSS THE SOUTH CENTRAL THROUGH THIS EVENING...AS
SOME LIGHT SNOW/RAIN MIX MAY OCCUR. OTHERWISE NO MAJOR CHANGES TO
ONGOING FORECAST. THE WINTER WEATHER ADVISORY FOR DICKEY COUNTY
SEEMS TO BE IN GOOD SHAPE.
UPDATE ISSUED AT 933 PM CDT WED APR 10 2013
NO MAJOR CHANGES WERE MADE TO THE ONGOING FORECAST. THE CURRENT
WINTER WEATHER ADVISORY FOR DICKEY COUNTY APPEARS TO BE IN GOOD
SHAPE. THE UPDATED PRODUCTS HAVE BEEN SENT.
UPDATE ISSUED AT 715 PM CDT WED APR 10 2013
A WINTER STORM ACROSS SOUTH DAKOTA CONTINUES TO SLOWLY SPIN NORTH
INTO SOUTHEASTERN NORTH DAKOTA THIS EVENING. EVEN THOUGH REGIONAL
RADARS ARE DETECTING ECHOES ACROSS SOUTH CENTRAL NORTH DAKOTA INTO
THE JAMES RIVER BASIN...NONE OF THE SNOW IS REACHING THE GROUND.
THE 00 UTC KBIS SOUNDING SHOWS A LARGE DRY LAYER FROM THE SURFACE
TO 650 MB CAUSING THE SNOW TO EVAPORATE BEFORE REACHING THE
GROUND. THE THERMODYNAMIC PROFILE OVER DICKEY COUNTY INDICATES
THIS LAYER SHOULD BECOME SATURATED BY AROUND SUNRISE THURSDAY
MORNING. THIS SHOULD ALLOW SNOW TO BEGIN REACHING THE GROUND AND
ACCUMULATING. THE CURRENT WINTER WEATHER ADVISORY FOR DICKEY
COUNTY LOOKS GOOD FOR THIS UPDATE WITH NO MODIFICATIONS REQUIRED.
FOR THIS UPDATE...ADJUSTED THE HOURLY SENSIBLE WEATHER GRIDS BASED
ON CURRENT OBS/TRENDS. THE UPDATED GRIDDED/TEXT PRODUCTS HAVE BEEN
SENT.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 330 PM CDT WED APR 10 2013
NORTHEAST FLOW OF COOL AND DRY AIR ORIGINATING FROM SURFACE HIGH
PRESSURE ACROSS MANITOBA HAS KEPT MOST OF THE AREA SOUTH OF
INTERSTATE 94 DRY SO FAR. HOWEVER...TONIGHT...THE H500 LOW WILL
MOVE FROM NEBRASKA/SOUTH DAKOTA BORDER NORTHEAST TO SOUTHWEST
MINNESOTA BY THURSDAY EVENING. THIS WILL INCREASE THE POTENTIAL
FOR LIGHT SNOW ACROSS SOUTHEAST NORTH DAKOTA. THE COUNTIES OF
MCINTOSH AND LAMOURE AND WILL POSSIBLY SEE 1 TO 3 INCHES OF SNOW
BY THURSDAY EVENING. DICKEY COUNTY WILL SEE AROUND 4 ACROSS ITS
SOUTHEAST. SO ISSUED A WINTER WEATHER ADVISORY FRO DICKEY COUNTY
BEGINNING MIDNIGHT TONIGHT THROUGH THURSDAY EVENING.
WITH THE UPPER LOW IN MINNESOTA...THE NEXT SHORTWAVE WILL BE
SLOWED AS IT MOVES INTO EASTERN MONTANA. BUT DO THINK THERE WILL
BE A SLIGHT CHANCE FOR RAIN OR SNOW THURSDAY AFTERNOON FAR WEST.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 330 PM CDT WED APR 10 2013
HIGHLIGHTING THE EXTENDED WILL BE CONTINUED BELOW NORMAL
TEMPERATURES AND A POTENTIAL SIGNIFICANT STORM SYSTEM SATURDAY INTO
MONDAY.
BELOW NORMAL TEMPERATURES ARE CONTINUED TO BE FAVORED ACROSS WESTERN
AND CENTRAL NORTH DAKOTA FOR THE DURATION OF THE LONG TERM FORECAST
UNDER AN UPPER LEVEL CENTRAL CONUS TROUGH.
LOOKING AHEAD TO THE STORM SYSTEM LATE SATURDAY INTO MONDAY...THE
12Z DETERMINISTIC MODELS ALL HAVE AN UPPER LEVEL WAVE COMING OUT OF
THE GULF OF ALASKA AND PROPAGATING INTO THE NORTHERN PLAINS LATE
SATURDAY INTO SUNDAY. MODELS HAVE SLOWED DOWN ON THE ARRIVAL OF
PRECIPITATION TO THE WESTERN PART OF NORTH DAKOTA SINCE
YESTERDAY...WITH THE GFS STILL HAVING THE SYSTEM ARRIVE THE
EARLIEST. DEPENDING ON WHEN THE PRECIPITATION ARRIVES...EXPECT A
RAIN SNOW MIX EARLY SATURDAY NIGHT AND SUNDAY AFTERNOON IN
NORTHWESTERN AND SOUTH CENTRAL NORTH DAKOTA...WITH ALL SNOW EXPECTED
LATE SATURDAY NIGHT INTO SUNDAY MORNING AND ONCE AGAIN SUNDAY
EVENING INTO MONDAY MORNING. PRECIPITATION SHOULD BE ALL SNOW NORTH
CENTRAL FOR THE ENTIRETY OF THE SYSTEM. HEAVIEST ACCUMULATIONS LOOK
TO BE FOR NORTHERN NORTH DAKOTA. THE 12Z ECMWF IS THE DEEPEST OF THE
DETERMINISTIC MODELS WITH THE GEM MORE OF A COMPROMISE BETWEEN THE
STRONGER ECMWF AND THE LESS ORGANIZED 12 UTC GEFS AND ITS ENSEMBLE
AND MEMBERS. THIS SYSTEM WILL HAVE TO BE CLOSELY MONITORED FOR
POTENTIAL HAZARDOUS WINTER WEATHER CONDITIONS FOR NORTHERN NORTH
DAKOTA AND THE POTENTIAL ADDITION OF SIGNIFICANT SNOW WATER TO THE
SOURIS RIVER BASIN.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 102 AM CDT THU APR 11 2013
VFR CONDITIONS WILL GIVE WAY TO MVFR CONDITIONS IN LIGHT SNOW AFTER
12Z FOR KJMS...FOLLOWED BY KBIS AFTER 17Z... THEN KMOT AFTER 00Z...AS
THE STORM SYSTEM CURRENTLY OVER SOUTH DAKOTA MOVES NORTH. ACROSS
THE WESTERN TERMINALS KDIK/KISN...MVFR CONDITIONS WILL DEVELOP AS
CEILINGS LOWER AHEAD OF THE NEXT STORM SYSTEM APPROACHING FROM THE
WEST.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 4 AM EARLY THIS MORNING TO 1 AM CDT
FRIDAY FOR NDZ051.
&&
$$
UPDATE...LTH
SHORT TERM...WAA
LONG TERM...MM
AVIATION...LTH
AREA FORECAST DISCUSSION
NWS SIOUX FALLS SD
1034 PM CDT WED APR 10 2013
.UPDATE...
ISSUED AT 1030 PM CDT WED APR 10 2013
SNOW CONTINUES TO INCREASE IN INTENSITY ACROSS THE REGION AS THE PV
ANOMALY MOVES IN. HAD ONE BAND OF HEAVIER SNOW SET UP WEST OF SIOUX
FALLS FROM DIXON COUNTY NEBRASKA TO MCCOOK COUNTY SOUTH DAKOTA...AND
OTHER HEAVIER BAND WAS ACROSS NORTHWEST IOWA. THIS EASTERN BAND
ACTUALLY CONTAINS MAINLY SLEET OR EVEN SOME RAIN OR FREEZING RAIN AS
JUST ENOUGH OF A WARM LAYER ALOFT REMAINS. AS THE UPPER LOW OVER
WESTERN NEBRASKA MOVES EAST THE SYSTEM BEGINS TO TAKE ON A BIT OF A
NEGATIVE TILT. THIS SHOULD RESULT IN THE TWO BANDS MENTIONED ABOVE
MERGING AND RETROGRADING A BIT NORTHWEST...AS CURRENTLY APPEARS TO BE
HAPPENING. MEANWHILE DRY AIR ALOFT WILL CONTINUE TO WORK IN FROM THE
SOUTH...WITH THE SNOWFALL BAND EVENTUALLY BECOMING ORIENTED MORE EAST
TO WESTERLY. WHERE THIS ENDS UP HAPPENING WILL BE WHERE THE HEAVIEST
SNOW FALLS. LATEST HRRR AND NAM CONTINUE TO SUGGEST THIS HAPPENS
ALONG AND NORTH OF INTERSTATE 90. SNOW WILL BE HEAVY AT TIMES THROUGH
THE NIGHT WITH STEEP LAPSE RATES ALOFT...AND STILL CAN NOT RULE OUT
AN ISOLATED RUMBLE OF THUNDER.
SO WHAT DOES THIS MEAN FOR SNOW AMOUNTS? WELL REALLY NOT MUCH OF A
CHANGE. INCREASED AMOUNTS SOME JUST WEST OF SIOUX FALLS WHERE THE
EARLIER BAND WAS SETUP. DECREASED AMOUNTS SOME ACROSS NORTHWEST IOWA
WHERE MORE SLEET IS MIXING IN AND RATIOS ARE LOWER DUE TO THE LIFT
BEING CONCENTRATED IN A WARMER LAYER. ALSO DECREASED AMOUNTS SOME
WEST OF THE JAMES RIVER ACROSS SOUTH CENTRAL SD...WHERE RADAR TRENDS
AND HRRR SUGGEST THE HEAVIER SNOW STAYS EAST...WITH ONLY AN INCH OR
TWO OF ADDITIONAL ACCUMULATION. STILL LOOKS LIKE SOUTHWEST MINNESOTA
WILL SEE THE HIGHEST TOTALS WITH 8 TO 12 INCHES. THING TO WATCH THERE
HOWEVER WILL BE SLEET. DUAL POL DATA SUGGESTS WARM LAYER CURRENTLY
EXTENDS FROM LINCOLN COUNTY MINNESOTA SOUTH INTO NORTHWEST IOWA. IF
THIS WARM LAYER HOLDS ON SNOW TOTALS COULD BE HELD DOWN A BIT IN
THOSE AREAS. ELSEWHERE...STILL LOOKING LIKE 6 TO 8 INCHES IN SIOUX
FALLS AND SURROUNDING AREAS. MOST OF THE ACCUMULATING SNOW SHOULD BE
BEFORE 12Z ALONG AND SOUTH OF INTERSTATE 90...ALTHOUGH LIGHT SNOW AND
FLURRIES WILL LINGER THROUGH THE DAY.
&&
.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 351 PM CDT WED APR 10 2013
MORE COMPLEX WEATHER TONIGHT WITH THE THIRD MAJOR WAVE IN AS MANY
DAYS. ONE WAVE WAVE MOVING THROUGH THE CWA THIS AFTERNOON WITH SNOW
AND SLEET MOVING NORTH AND SHOULD MAINLY BE OUT OF THE CWA BY LATE
AFTERNOON. UPPER LEVEL SUPPORT FROM THE NEXT AND POSSIBLY STRONGEST
WAVE OF THIS SYSTEM MOVING INTO KANSAS THIS AFTERNOON WITH LIGHT
PRECIPITATION EXPANDING IN COVERAGE OVER EASTERN KANSAS AND
NEBRASKA. VERY STRONG PV ADVECTION WILL MOVE INTO EASTERN PARTS OF
THE AREA EARLY THIS EVENING WITH THE STRONGEST LIFT FROM ABOUT 3Z TO
9Z WITH AN EXCEPTIONAL AMOUNT OF PV ADVECTION. ALONG AND AHEAD OF
THIS UPPER LEVEL SUPPORT A VERY STRONG TROWAL WILL DEVELOP WITH VERY
STRONG LIFT PER THE NET ISENTROPIC ADIABATIC OMEGA AT MANY LEVELS
AROUND 6Z. THE STRONGEST LIFT IN THE 800MB TO 700MB LAYER WITH
UPWARDS OF 50 KNOTS OF FLOW ADVECTING WESTWARD. AMAZINGLY THERE IS
VIRTUALLY NO DIFFERENCE FROM MODEL TO MODEL WITH THE 12Z GEM/GFS/NAM
AND 20 OF THE 21 MEMBERS OF THE 9Z SREF PAINTING ABOUT 0.75 TO 1.20
INCHES OF LIQUID WATER OVER MUCH OF THE NORTHEAST HALF OF THE CWA.
WILL BE AIMING FOR SNOWFALL RATIOS OF ABOUT 8-9:1 EARLY ON WITH A
SOUNDING BARELY SUPPORTIVE ON SNOWFALL. AS THE NIGHT GOES ON AND
SOMEWHAT COLDER AIR WRAPS IN THE RATIOS SHOULD EXPAND TO ABOUT
10-11:1 BUT DOUBT ANY HIGHER THAN THAT. THIS WILL KEEP A LOT OF THE
BLOWING SNOW TO A MINIMUM WITH COMPACTION AND PARTIAL MELTING
THROUGH THE DAY THURSDAY WITH TEMPERATURES NEAR 30. THE TROWAL WRAPS
UP AND SNOW WILL CONTINUE OFF AND ON ALL DAY THURSDAY WITH THE
BETTER SNOW AMOUNTS OVER THE NORTHERN AND EASTERN PARTS OF THE CWA.
OVERALL IN THE 24 PERIOD FROM ABOUT 0Z TONIGHT THROUGH OZ FRIDAY
EXPECTING ABOUT 10-12 INCHES OF SNOW IN SOUTHWEST MINNESOTA AND
ABOUT 5 TO 10 SOUTH AND WEST OF THERE...EXCEPT 4 TO 6 FROM ABOUT
SIOUX CITY TO STORM LAKE. ICING NOT EXPECTED TO BE A MAJOR PROBLEM
BUT ANOTHER TENTH OF AN INCH OR LESS POSSIBLE FROM ABOUT SPENCER TO
SIOUX CITY THIS EVENING.
.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 351 PM CDT WED APR 10 2013
TROWAL PERSISTS ACROSS OUR NORTHEAST CWA INTO THURSDAY EVENING. WHILE
LIFT SHOULD GRADUALLY WEAKEN AS UPPER LOW SLOWLY SHIFTS EAST THROUGH
SOUTHERN MINNESOTA THURSDAY NIGHT/FRIDAY MORNING...WILL LIKELY SEE
ADDITIONAL LIGHT ACCUMULATIONS...PERHAPS UP TO ANOTHER INCH...ACROSS
NORTHEAST THIRD OF THE CWA INTO THURSDAY NIGHT. STILL A LITTLE BREEZY
WITH NORTHERLY WINDS CONTINUING AT 15-20 MPH...BUT WITH WET NATURE OF
THE SNOWFALL DO NOT EXPECT BLOWING/DRIFTING TO BE MUCH OF AN ISSUE AS
THE FALLING SNOW IS TAPERING OFF THURSDAY NIGHT. ONE TRAILING WAVE
DROPS THROUGH THE DAKOTAS/MINNESOTA FRIDAY NIGHT...BUT BETTER LIFT
AND MOISTURE LOOK TO REMAIN NORTHEAST OF THE AREA AND WILL KEEP OUR
AREA DRY FOR FRIDAY NIGHT AND SATURDAY. LATE FRIDAY AFTERNOON WEST...
AND SATURDAY MORNING EAST...WILL BE FIRST REAL POTENTIAL FOR SUNSHINE
ACROSS THE AREA AS WEAK UPPER LEVEL RIDGE MOVES ACROSS THE PLAINS.
THIS WILL BE SHORT-LIVED THOUGH...AS WARM ADVECTION AHEAD OF THE NEXT
BROAD UPPER LEVEL TROUGH BEGINS TO INCREASE CLOUDS AGAIN BY SATURDAY
AFTERNOON. MODELS STILL IN FAIRLY DECENT AGREEMENT IN BRINGING CHANCE
OF PRECIP BACK TO THE AREA SATURDAY NIGHT TO SOME DEGREE...WITH BEST
CHANCE IN THE NORTH WHERE WE WILL CONTINUE SOME LIKELY POPS.
MODELS THEN DIVERGE A BIT MORE IN HANDLING EVOLUTION OF THE WESTERN
TROUGH...WITH ECMWF PRODUCING A STRONGER LEAD WAVE LIFTING NORTHEAST
INTO ONTARIO BY LATE MONDAY...WHILE GFS/GEM DIG A BIT MORE ENERGY
INTO THE SOUTHERN ROCKIES. IN EITHER CASE...SPLITTING OF ENERGY WILL
BRING REDUCED CHANCE OF PRECIPITATION TO OUR REGION BY SUNDAY NIGHT
AND MONDAY. FOR THE MOST PART...TEMPERATURES THIS WEEKEND EXPECTED TO
BE WARM ENOUGH FOR RAIN...THOUGH COULD SEE A PERIOD OF LIGHT SNOW OR
POSSIBLY LIGHT FREEZING RAIN NORTH OF I-90 SATURDAY NIGHT INTO EARLY
SUNDAY...DEPENDING ON HOW QUICKLY WARM AIR ALOFT AND AT THE SURFACE
EXPANDS NORTH. GIVEN UNCERTAINTY...WITH JUST STICK WITH RAIN/SNOW
MENTION FOR NOW.
MIDWEEK ATTENTION TURNS TO SOUTHERN ROCKIES TROUGH AS IT BEGINS TO
EJECT INTO THE PLAINS. WHILE IT DOES NOT LOOK LIKE A SOLID 48 HOURS
OF PRECIPITATION...DIFFICULT TO NARROW DOWN TIMING AND NOT KEEP LOW-
MID RANGE CHANCE POPS IN MONDAY NIGHT THROUGH WEDNESDAY PERIOD AS
VARIOUS WEAK WAVES KICK NORTHEAST OUT OF THE BASE OF THE TROUGH.
TEMPERATURES ALOFT THROUGH THIS PERIOD GENERALLY BELOW ZERO...EVEN
AT 925MB...SO PRECIP TYPE WILL BE MORE DEPENDENT ON SURFACE TEMPS...
WHICH CURRENTLY ARE FORECAST TO WARM INTO THE 40S DURING THE DAY...
BUT COULD DROP NEAR/BELOW FREEZING AT NIGHT. THUS WILL BROAD BRUSH
WITH CHANCE OF RAIN/SNOW WORDING THROUGH THIS PERIOD FOR NOW...BUT
BETTER TIMING ON PRECIP CHANCES ALONG WITH PRECIP TYPES SHOULD BE
REFINED AS WE MOVE THROUGH THE WEEKEND.
&&
.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 622 PM CDT WED APR 10 2013
GENERALLY IFR CONDITIONS CAN BE EXPECTED THROUGH 00Z FRIDAY. LIGHT
SNOW MIXED WITH LIGHT FREEZING DRIZZLE THIS EVENING WILL BECOME
WIDESPREAD SNOW DURING THE NIGHT AS IT SPREADS NORTH ACROSS THE
REGION...AND THEN TAPER OFF FROM THE SOUTH AFTER 10Z TONIGHT AND
INTO THURSDAY MORNING. VISIBILITIES WILL DROP TO LESS THAN 1/2 MILE
AT TIMES IN THE HEAVIER SNOW. LATER THIS EVENING THROUGH EARLY
THURSDAY MORNING.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR SDZ038>040-
053>056-059>062-065>071.
WINTER STORM WARNING UNTIL 7 AM CDT THURSDAY FOR SDZ050-052-057-
058-063-064.
MN...WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR MNZ071-072-080-
081-089-090-097-098.
IA...WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR IAZ001>003-
012>014-020.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THURSDAY FOR IAZ021-022-
031-032.
NE...WINTER STORM WARNING UNTIL 1 PM CDT THURSDAY FOR NEZ013.
WINTER WEATHER ADVISORY UNTIL 1 PM CDT THURSDAY FOR NEZ014.
&&
$$
UPDATE...CHENARD
SHORT TERM...08
LONG TERM...JH
AVIATION...
AREA FORECAST DISCUSSION
NWS HOUSTON/GALVESTON TX
1150 PM CDT WED APR 10 2013
.DISCUSSION...
SEE AVIATION FOR 06Z TAF ISSUANCE
&&
.AVIATION...
SHRA HAVE EXPANDED IN COVERAGE THIS EVENING WITH TSRA DEVELOPING
SOUTH OF INTERSTATE 10 AND EAST OF INTERSTATE 45. THIS CONVECTION
LIKELY DUE TO GOOD UPPER LEVEL SUPPORT PROVIDED BY DIFFLUENT FLOW
ALOFT AND ALSO BY SHORTWAVE DISTURBANCE ROTATING AROUND THE BASE
OF THE MAIN TROUGH ALONG THE RIO GRANDE. HAVE ADDED VCTS WITH
TEMPO TSRA FOR ALL SITES WITH THE EXCEPTION OF CLL AND UTS.
ACTIVITY SHOULD BEGIN TO DECREASE IN COVERAGE AND INTENSITY AFTER
09Z WITH CIGS IMPROVING THROUGH MID MORNING. FORECAST REASONING
FOR REMAINDER OF TAF VALID PERIOD REMAINS UNCHANGED WITH VFR
CONDITIONS DEVELOPING. 38
&&
.PREV DISCUSSION... /ISSUED 834 PM CDT WED APR 10 2013/
UPDATE...
EVENING FORECAST UPDATE.
DISCUSSION...
COLD FRONT HAS PUSHED INTO THE UPPER TX COASTAL WATERS THIS
EVENING BUT HAS NOT MADE A WHOLE LOT OF PROGRESS. FRONT HAS SLOWED
WITH IT BECOMING MORE NNE/SSW ORIENTED. STARTING TO GET SOME
ELEVATED SHOWERS OVER THE FRONT MAINLY EAST OF A CONROE...KATY TO
BAY CITY LINE. WATER VAPOR IMAGERY SHOWS SHORTWAVE TROUGH AND JET
STREAK COMING THROUGH MEX INTO THE RIO GRANDE VALLEY/S TX. THIS
MAY ENHANCE ELEVATED CONVECTION OVER SE TX DURING THE EARLY
MORNING HOURS. OVERALL THINK MODELS ARE ON TRACK BUT THAT
GFS/ECMWF ARE OVER DOING PRECIP AMOUNTS AND COVERAGE. THINK THERE
WILL BE SCATTERED ACTIVITY BUT PRECIP AMOUNTS WILL DEPEND ON
REDEVELOPMENT OF CELLS AND TRAINING. DECIDED TO KEEP POPS AROUND
50 PERCENT BUT COULD SEE ADJUSTMENT FOR HIGHER POPS. THE HRRR HAS
BEEN DOING FAIRLY WELL WITH ITS CONVECTIVE TRENDS SO FAR AND THINK
WITH IT DEVELOPING CONVECTION AFTER 07Z TONIGHT...COASTAL AREAS
COULD SEE SOME DECENT RAIN. WILL CONTINUE TO MONITOR TRENDS IN
CONVECTION BUT MAY NEED TO WATCH FOR HOW MUCH CONVECTION FORMS
AFTER MIDNIGHT WITH THE APPROACHING SHORTWAVE.
39
PREV DISCUSSION... /ISSUED 640 PM CDT WED APR 10 2013/
DISCUSSION...
SEE AVIATION FOR 00Z TAF ISSUANCE
AVIATION...
SURFACE FRONT HAS PUSHED THROUGH ALL SOUTHEAST TEXAS TERMINALS
THIS EVENING. WIND GUSTS ARE PICKING UP ACROSS THE NORTHERN HALF
OF THE REGION AS THE UPPER LEVEL FRONT ARRIVES AND THESE SHOULD
CONTINUE TO OVERSPREAD THE REST OF THE REGION WITHIN THE NEXT HOUR
OR SO.
MAIN CONCERN THIS EVENING REMAINS EXTENT OF IFR CIGS AND POTENTIAL
OVERNIGHT SHRA ACTIVITY. SEVERAL OF THE MODELS REDEVELOP
PRECIPITATION BEHIND THE FRONT ACROSS AREAS ALONG AND SOUTH OF
INTERSTATE 10 AND EAST OF US 59...AFFECTING ALL SITES EXCEPT CLL.
WILL KEEP MENTION OF VCSH THROUGH 09Z FOR SOUTHERN SITES BUT AM
EXPECTING ACTIVITY TO WANE OR PUSH EAST OF THE REGION BY THEN. ONE
MODEL DOES SUPPORT SOME STRONGER SHRA OR PERHAPS ISOLATED TSRA
AROUND 09Z DUE TO STRONG UPPER LEVEL DIFFLUENCE BUT AM NOT
CONFIDENT IN THIS SOLUTION AND WILL KEEP MENTION OF TSRA OUT OF
THE TAFS FOR NOW. AS PCPN BEGINS TO END EXPECT IFR CIGS TO BEGIN
IMPROVING...FIRST AT CLL AND THEN ACROSS THE REST OF THE REGION
BETWEEN 09-12Z THURSDAY. AM EXPECTING SCT250 OR SKC BY
MIDAFTERNOON THURSDAY WITH WINDS BECOMING NORTHEAST AFTER 11/00Z
AS BROAD SURFACE HIGH PRESSURE SHIFTS INTO THE MISSISSIPPI RIVER
VALLEY. 38
PREV DISCUSSION... /ISSUED 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 / 50 20 0 0 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 7 AM CDT THURSDAY FOR THE FOLLOWING
ZONES: GALVESTON BAY...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.
&&
$$
DISCUSSION...39
AVIATION/MARINE...38
AREA FORECAST DISCUSSION
NWS MIAMI FL
1002 AM EDT THU APR 11 2013
.UPDATE...
THE LATEST RUC 400 MB ANALYSIS OVERLAID ONTO THE LATEST WATER
VAPOR LOOP SHOWED A RIDGE AXIS EXTENDING NORTH AND NORTHEAST FROM THE
EASTERN GULF OF MEXICO TO NORTHERN FLORIDA AND GENERALLY INDICATES
THIS RIDGE BUILDING EASTWARD OVER THE LOCAL AREA THROUGH THE
COURSE OF THE DAY TODAY. MODEL SOUNDINGS REFLECT THIS AND INDICATE
A DECENT SUBSIDENCE INVERSION JUST ABOVE 500 MB FROM TBW TO MIA.
DESPITE THE STEEP LAPSE RATES NOTED IN THE SOUNDINGS FROM
600-500MB...THIS COULD BE A LIMITING FACTOR FOR DEEP CONVECTION
AND THE OVERALL THUNDERSTORM POTENTIAL THIS AFTERNOON/EARLY
EVENING. HOWEVER...IF THIS IS ERODED...A FEW STRONG STORMS WILL
BECOME A POSSIBILITY LATER TODAY. THESE LAPSE RATES COMBINED WITH
THE MID-LEVEL DRY AIR COULD RESULT IN STRONG WINDS AND SMALL HAIL
AS THE MAIN IMPACTS FROM ANY STRONG STORM THAT DOES DEVELOP.
CONSIDERING THE MEAN LOW-LEVEL FLOW IS SSE UP TO 700MB...THE BEST
CHANCE FOR THESE STORMS WILL REMAIN OVER THE NORTHERN SECTIONS OF
THE LOCAL AREA...ESPECIALLY FROM NAPLES TO THE LAKE REGION.
OUTSIDE OF A FEW MINOR TWEAKS WITHIN THE GRIDDED FORECAST BASED ON
THE MORNING OBSERVATIONS AROUND THE LOCAL AREA...NO MAJOR CHANGES
ARE ANTICIPATED. 85/AG
&&
.PREV DISCUSSION... /ISSUED 727 AM EDT THU APR 11 2013/
AVIATION...
VFR CONDITIONS THROUGH THE PERIOD AT ALL TERMINALS. HIGH PRESSURE
OVER THE WESTERN ATLANTIC WATERS WILL KEEP AN EASTERLY FLOW ACROSS
SOUTH FLORIDA TODAY...GUSTING UP TO 20 KTS AT TIMES. A FEW SHOWERS
COULD DEVELOP AND MOVE NEAR THE TERMINALS...BUT COVERAGE AND
LENGTH WILL BE NOT SIGNIFICANT THEREFORE...NO NEED TO MENTION ON
TAFS AT THIS TIME. WILL AMEND IF NECESSARY. WINDS EXPECTED TO
DECREASE IN SPEED AT AROUND 12/02Z.
PREV DISCUSSION... /ISSUED 346 AM EDT THU APR 11 2013/
SHORT TERM...
WITH HIGH PRESSURE TO THE EAST OF SOUTH FLORIDA, A SOUTHEASTERLY
FLOW HAS BROUGHT PLENTY OF MOISTURE TO INITIATE SOME AFTERNOON
THUNDERSTORMS ONCE AGAIN TODAY. THESE STORMS WILL MAINLY BE IN THE
LAKE REGION ONCE AGAIN. IN TERMS OF DYNAMICS, THERE WILL BE 500MB
VORTICITY ADVECTION MOVING ACROSS THE AREA. MODELS INDICATE
BETWEEN 600 AND 1000 JOULES OF CAPE. TYPICAL NEGATIVE LIS, AND
STRONG 500MB OMEGA VALUES. THE 700 MB OMEGAS ARE LESS THAN
YESTERDAY. THE 500MB RIDGE IS BREAKING DOWN, AND THERE WILL BE A
WEAK SHORT WAVE. JET SUPPORT TODAY WILL BE NEGLIGIBLE. SO, HAVE
KEPT CHC POPS OVER THE NORTHWEST AREA, DOWN TO ABOUT I75. IT DOES
LOOK TO BE SOMEWHAT MORE COVERAGE TODAY. ALSO, WHILE THERE WILL BE
SOMEWHAT OF A SEA BREEZE, IT MAY BE HARD TO DETECT AT THE SFC AS
WINDS WILL BE BREEZY TODAY.
TOMORROW WILL SEE A SIMILAR SETUP, EXCEPT TRANSLATED EASTWARD.
ALSO, WINDS TOMORROW WILL TURN MORE SOUTHERLY AND PERHAPS EVEN
MORE SOUTHWESTERLY.
HIGH TEMPERATURES FOR THE NEXT COUPLE OF DAYS WILL CONTINUE TO BE
IN THE MID TO UPPER 80S, TO AROUND 90. LOW TEMPERATURES WILL BE
FAIRLY WARM, WITH LOWS IN THE MID TO UPPER 60S IN THE INTERIOR AND
LOW TO MID 70S ALONG THE COASTAL AREAS.
CONDITIONS WILL BECOME MORE INTERESTING BY SATURDAY MORNING. A LOW
PRESSURE SYSTEM OVER THE PLAINS WILL MOVE EASTWARDS FOR THIS
WEEKEND. THIS SYSTEM WILL BRING A COLD FRONT TO THE FLORIDA
PENINSULA. THE FRONT IS CURRENTLY PROGGED TO STALL JUST NORTH OF
LAKE OKEECHOBEE. THIS WILL KEEP SOUTH FLORIDA IN THE WARM SECTOR
ON SATURDAY. THE MAIN ENERGY ASSOCIATED WITH THE FRONT WILL BE
WELL TO THE NORTH. THERE WILL NOT BE MUCH IN THE WAY OF ANYTHING
FOR SOUTH FLORIDA, EXCEPT INCREASING THE CHANCE FOR THUNDERSTORMS
SATURDAY AFTERNOON. THE AREA OF HIGHER POPS WILL GENERALLY BE
NORTH OF I75, AND HIGHER AS YOU GO NORTH, GETTING CLOSER TO THE
FRONTAL BOUNDARY. IT IS STILL FAR ENOUGH OUT THAT THE CHANCES WILL
CHANGE FOR ANY GIVEN AREA, UP OR DOWN, DEPENDING ON HOW FAR SOUTH
THE FRONT CAN GET. FOR NOW, DID NOT GO ABOVE 50 POPS FOR SATURDAY
AFTERNOON.
LONG TERM...
THE STALLED FRONT WILL SIT AROUND FOR A COUPLE OF DAYS AFTER,
MAKING LITTLE PROGRESS AND SHOULD EVENTUALLY WASH OUT, PROBABLY
FOR THE BEGINNING OF THE WEEK. AS IT DOES WASH OUT, HIGH PRESSURE
WILL AGAIN BRING A SOUTH TO SOUTHEASTERLY FLOW TO SOUTH FLORIDA,
ALLOWING FOR A CHANCE OF A FEW AFTERNOON THUNDERSTORMS TO POPS UP.
MODELS ARE INDICATING A SHORT WAVE MOVING ACROSS NORTH AND
CENTRAL FLORIDA SUNDAY NIGHT, BUT CURRENTLY THINKING IT WILL NOT
AFFECT THE CWA. SO, ONCE THE FRONT WASHES OUT, NOT EXPECTING ANY
REAL PATTERN CHANGE FOR THE REMAINDER OF THE FORECAST PERIOD. HIGH
TEMPERATURES WILL CONTINUE TO RANGE FROM THE LOW TO MID 80S ALONG
THE COAST TO MID TO UPPER 80S, POSSIBLY EVEN LOW 90S IN THE
INTERIOR OF THE STATE.
MARINE...
HIGH PRESSURE WILL REMAIN TO THE EAST OF THE AREA. THIS WILL BRING
CONTINUOUS STIFF SOUTHEAST WINDS OF 15 TO 20KTS TODAY. THEY WILL
BEGIN TO TURN MORE SOUTHERLY TOMORROW, BUT WILL CONTINUE TO BE
FAIRLY STIFF, ALTHOUGH SLIGHTLY LOWER TOMORROW. THERE IS A SLIGHT
CHANCE OF A SHOWER THROUGH TONIGHT AND POSSIBLE A SHOWER OR A
THUNDERSTORM TOMORROW. A WEAK COLD FRONT WILL STALL OVER THE AREA
SATURDAY, BRINGING AN INCREASED CHANCE OF A SHOWER AND/OR A
THUNDERSTORM FOR SATURDAY AFTERNOON.
FIRE WEATHER...
FIRE WEATHER CONCERNS ARE AT A LOW RIGHT NOW AS THERE IS PLENTY OF
SURFACE MOISTURE AROUND. IT WILL BE BREEZY TODAY, WITH WINDS OUT
OF THE SOUTHEAST. THERE IS A CHANCE OF A THUNDERSTORM IN THE
INTERIOR AREAS, ESPECIALLY NORTH, TOWARDS LAKE OKEECHOBEE. THIS
WILL REPEAT AGAIN TOMORROW, EXCEPT WINDS WILL BE MORE SOUTHERLY.
THEN, FOR THE WEEKEND, A COLD FRONT WILL APPROACH SOUTH FLORIDA,
BUT IS NOT EXPECTED TO MAKE IT INTO THE AREA. MODELS ARE SHOWING
IT TO STALL OVER CENTRAL FLORIDA. BUT, IT WILL INCREASE THE CHANCE
FOR THUNDERSTORMS ON SATURDAY AFTERNOON, AND MAYBE ON SUNDAY
AFTERNOON, BEFORE WASHING OUT. WITH WINDS JUST ABOVE THE SURFACE
OF AROUND 15 TO 20 MPH, NOT EXPECTING FOG FORMATION TONIGHT.
HOWEVER, WINDS ARE LOOKING AS THEY MAY DIMINISH AS THE FRONT
STALLS, WHICH MAY ALLOW FOG FOR SATURDAY AND SUNDAY MORNINGS.
PREV DISCUSSION... /ISSUED 143 AM EDT THU APR 11 2013/
AVIATION...
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC WATERS
TODAY...AS LOW PRESSURE MOVES THROUGH THE GREAT LAKES. THIS WILL
ALLOW FOR A BREEZY TO WINDY SOUTHEAST WIND FLOW OVER THE SOUTH
FLORIDA TAF SITES TONIGHT WITH SPEEDS BETWEEN 15 TO 20 KNOTS WITH
GUSTS UP TO 28 KTS. THE SOUTHEAST WIND FLOW WILL CONTINUE
TONIGHT...BUT THE SPEEDS WILL DECREASE TO 10 KNOTS OR LESS AT THE
TAF SITES OVER SOUTH FLORIDA.
THE EAST COAST TAF SITES COULD SEE A SHOWER OR TWO ON THE
SOUTHEAST WIND FLOW TODAY...BUT THE COVERAGE AND DURATION WILL BE
FEW AND FAR BETWEEN. SO WILL LEAVE THE EAST COAST TAF SITES DRY AT
THIS TIME FOR TODAY INTO TONIGHT. KAPF TAF SITE COULD SEE SOME
SHOWERS IN THE AREA WITH MORE COVERAGE. SO HAVE ADDED VCSH TO KAPF
TAF SITE AFTER 15Z FOR TODAY.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS FOR
TODAY INTO TONIGHT FOR ALL OF THE TAF SITES.
AVIATION...54/BNB
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 83 73 84 72 / 20 20 40 20
FORT LAUDERDALE 83 75 84 74 / 20 20 30 20
MIAMI 83 74 85 74 / 20 20 30 20
NAPLES 84 71 83 70 / 20 20 20 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION
NWS JACKSON KY
650 AM EDT THU APR 11 2013
.UPDATE...
ISSUED AT 650 AM EDT THU APR 11 2013
STARTING TO SEE A FEW MID LEVEL RETURNS CREEPING INTO THE SOUTHWEST
PORTION OF THE AREA. HOWEVER...BASES REMAIN MUCH TOO HIGH TO ALLOW
FOR AND PRECIPITATION REACHING THE GROUND. PRECIPITATION IS
ATTEMPTING TO PUSH INTO CENTRAL KENTUCKY THIS MORNING...BUT IS MAKING
VERY SLOW PROGRESS. THE LATEST RAP AND NAM SUGGEST A LATER ONSET OF
PRECIPITATION TODAY...POSSIBLY HOLDING OFF UNTIL 7 OR 8 PM THIS
EVENING FOR MUCH OF THE AREA. THE I-75 CORRIDOR MAY SEE THINGS START
A BIT EARLY TOWARDS 5 OR 6 PM. THESE TRENDS MAY NEED TO BE WATCHED.
WITH INSTABILITY ALREADY IN QUESTION...A LATER ONSET TOWARDS MID TO
LATE EVENING MAY LIMIT THE SEVERE THREAT AS INSTABILITY MAY SIMPLY
NOT BE THERE. IN FACT...THE LATEST HRRR SHOWS PRETTY ROBUST
CONVECTION TO THE SOUTH OF THE AREA BY MID AFTERNOON...SUGGESTING
THAT THE EARLIER ASSUMPTION ABOUT STORMS TO THE SOUTH ROBBING US OF
OUR INSTABILITY MAY BE TRUE. THESE TRENDS WILL HAVE TO BE MONITORED
THIS MORNING. CLEARLY...THIS IS NOT A CLEAR CUT SCENARIO FOR SEVERE
WEATHER. HAVE MADE SOME MINOR TWEAKS TO THE LATEST
TEMPERATURE/DEWPOINT CURVES...AND ADJUSTED SLIGHTLY THE ONSET OF
PRECIPITATION. NO NEED TO UPDATE THE FORECAST THROUGH.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 316 AM EDT THU APR 11 2013
STRONG COLD FRONT CURRENTLY EXTENDS FROM NORTHERN INDIANA...SOUTHWARD
INTO FAR WESTERN KENTUCKY. A LINE OF SHOWERS AND STORMS CONTINUES TO
PUSH EAST ALONG THIS FRONTAL BOUNDARY. MODELS ARE ALL IN PRETTY GOOD
AGREEMENT WITH THE POSITION AND TIMING OF THIS FRONT AS IT CROSSES
EASTERN KENTUCKY LATER TODAY. UNIDIRECTIONAL WIND SHEAR IS SUFFICIENT
TO WARRANT A WIND THREAT WITH ANY THUNDERSTORMS THAT DEVELOP. LCL`S
MAY GET LOW ENOUGH IN THE CUMBERLAND PLATEAU TO SUPPORT AN ISOLATED
TORNADO...BUT THOSE LCL`S GO WAY UP AS YOU GO NORTH AND EAST. ONSET
FOR PRECPITATION SHOULD BE SOMETIME AFTER 2 PM FOR MOST AREAS TODAY.
THE BIG QUESTION SURROUNDING SEVERE POTENTIAL IS WHETHER ENOUGH
INSTABILITY WILL EXISTS TO SUPPORT THUNDERSTORMS WITH STRONG
DOWNDRAFTS. USING SFC BASED PARCEL OF 80/58 PRODUCES AROUND 900J/KG
OF SBCAPE. ALTHOUGH THIS IS MARGINAL...IT SHOULD BE SUFFICIENT TO
SUPPORT THUNDERSTORMS AND THUS WE COULD SEE SOME STRAY DAMAGING WIND
GUSTS. THUS...WILL MAINTAIN THE SEVERE THREAT WORDING IN THE HWO. THE
POTENTIAL DOES EXIST THAT CONVECTION DEVELOPING TO OUR SOUTH LATER
THIS AFTERNOON COULD ROB EASTERN KENTUCKY AND LIMIT THE SEVERE THREAT
OVER THE AREA. HOWEVER...THIS WOULD BE TOUGH TO BASE A FORECAST
ON...SO GOING TO MAINTAIN THE SEVERE THREAT.
SEVERE THREAT WILL COME TO AN END BY MIDNIGHT AS COLD FRONT PUSHES
EAST OUT OF THE AREA. RAIN WILL EVENTUALLY END FROM WEST TO EAST
OVERNIGHT. SYSTEM SHOULD BE PROGRESSIVE ENOUGH TO LIMIT ANY
SIGNIFICANT FLOODING ISSUE...ESPECIALLY WITH THE LACK OF RECENT
RAINFALL. SIGNIFICANTLY COOLER WEATHER WILL RETURN TO THE AREA LATE
TONIGHT. THE MORE SIGNIFICANT COLD AIR STAYS TO OUR NORTHWEST ON
FRIDAY. ALTHOUGH TEMPERATURES WILL BE COOLER...AFTERNOON READINGS MAY
STILL CLIMB INTO THE LOWER 60S UNDER SUNSHINE. SOME LOW CLOUDS MAY
START THE DAY...BUT GUSTY SOUTHWEST WINDS SHOULD ERODE THESE CLOUDS
FAIRLY QUICKLY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU APR 11 2013
THE MODELS ARE IN REASONABLY GOOD AGREEMENT THROUGH THE EXTENDED AND
ONLY START TO SIGNIFICANTLY DIVERGE TOWARD THE END. THE ALL AGREE
THAT A DEEP CLOSED LOW OVER THE GREAT LAKES WILL ROTATE OUT OF THE
AREA TO THE NORTHEAST. THIS PROCESS IS FACILITATED BY A DECENT
SHORTWAVE THAT WILL TRACK THROUGH THE OHIO VALLEY ON SATURDAY...WITH
THE ECMWF REPRESENTING A GOOD COMPROMISE BETWEEN THE SLOWER GEM AND
FASTER GFS. HEIGHTS WILL RISE IN THE WAKE OF THE UPPER LOW/S
DEPARTURE WITH A HINT OF RIDGING TAKING PLACE TO CLOSE OUT THE
WEEKEND. TO THE SOUTH OF THE AREA...A LOOSE CLUSTER OF ENERGY WILL
DRIFT PAST LATER THAT NIGHT AND MAY BE ENOUGH TO HAVE AN EFFECT ON
THE SENSIBLE WEATHER OF SOUTHEAST KENTUCKY. OTHERWISE...RENEWED
RIDGING WILL TAKE SHAPE OVER SOUTHEAST PORTION OF THE NATION
RESULTING IN RISING HEIGHTS THROUGH TUESDAY. THE MODELS ARE HINTING
THAT THIS PATTERN MAY BREAK DOWN LATER IN THE WEEK AS TROUGHING OUT
WEST STARTS TO MOVE EAST INTO THE PLAINS ON WEDNESDAY...FASTEST IN
THE GFS WHEN COMPARED TO THE 12Z ECMWF. IN ADDITION...A FEW WEAKER
PATCHES OF ENERGY WILL LIKELY START TO MAKE THEIR WAY THROUGH THE
REGION OUT AHEAD OF THE LARGER...INBOUND...SYSTEM.
SENSIBLE WEATHER WILL FEATURE A BRIEF COOL DOWN FOR THE START OF THE
WEEKEND AS HIGH PRESSURE SETTLES INTO THE AREA FOLLOWING THE LARGER
LOW PRESSURE SYSTEM EXITING TO THE NORTHEAST. THIS HIGH WILL QUICKLY
MODERATE...THOUGH...SO THAT EACH AFTERNOON WE CAN EXPECT
TEMPERATURES A FEW DEGREES HIGHER THAN THE PREVIOUS ONE THROUGH
TUESDAY. MORE IN THE WAY OF CLOUDS AND A BETTER POTENTIAL FOR
SHOWERS AND THUNDERSTORMS...LIKE A SUMMER TIME DIURNAL CONVECTIVE
PATTERN...MAY KEEP TEMPS A BIT LOWER ON WEDNESDAY THAN TUESDAY. THIS
POTENTIAL AND THE UNCERTAINTY OF THE TIMING FOR THE NEXT SYSTEM
MIDWEEK CALLS FOR LOW TO MID RANGE POP CHANCES FOR WEDNESDAY. THE
REST OF THE EXTENDED WILL LIKELY BE DRY...THOUGH CAN/T RULE OUT A
STRAY SHOWER EARLY MONDAY AS A WEAK SFC WAVE PASSES BY TO THE
SOUTH.
THE CR GRID LOAD CAME IN PRETTY DECENT...BUT DID NUDGE DOWN POPS
TUESDAY AND WEDNESDAY MORE TOWARDS THE 12Z ECMWF. ALSO MAKE SOME
SIGNIFICANT TERRAIN BASED ADJUSTMENTS FOR LOWS EACH NIGHT...
ANTICIPATING DECENT RIDGE TO VALLEY SPLITS THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 650 AM EDT THU APR 11 2013
HIGH/MID CLOUDS CONTINUE TO STREAM EAST ACROSS THE AREA. VFR
CONDITIONS SHOULD CONTINUE AT THE TAF SITES INTO MIDDAY TODAY. WINDS
WILL TURN GUSTY OUT OF THE SOUTH-SOUTHWEST BY LATE MORNING INTO THE
AFTERNOON AS A COLD FRONT ARRIVES FROM THE WEST. SHOWERS AND
THUNDERSTORMS SHOULD PUSH INTO CENTRAL AND EASTERN KENTUCKY AS EARLY
AS 20Z OR 21Z. CIGS SHOULD REMAIN ELEVATED INITIALLY. A FEW SEVERE
WIND GUSTS ARE POSSIBLE WITH ANY THUNDERSTORMS TODAY. AS THE FRONT
PASSES THIS EVENING...LOW LEVEL MOISTURE WILL SURGE EAST ACROSS THE
AREA DROPPING CIGS TO MVFR...THEN EVENTUALLY IFR LATER ON. RAIN
SHOULD PERSIST INTO THE FIRST HALF OF TONIGHT AS WELL...WHICH COULD
AID IN SOME PATCHY FOG FORMATION RESTRICTING VISIBILITIES AT TIMES.
STRATUS BUILD DOWN COULD OCCUR ONTO THE RIDGES WHICH MAY DROP
VISIBILITIES TO A QUARTER MILE OR LESS ON THE RIDGETOPS TONIGHT.
CLEARLY...LESS THAN IDEAL FLYING CONDITIONS WILL BE FOUND ACROSS
EASTERN KENTUCKY TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KAS
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
734 AM CDT THU APR 11 2013
.UPDATE...
12Z AVIATION DISCUSSION ADDED BELOW.
&&
.SHORT TERM...(TODAY THROUGH THURSDAY MORNING)
ISSUED AT 415 AM CDT THU APR 11 2013
WELL ADVERTISED PRECIPITATION BURST FINALLY STARTING TO COME
TOGETHER THIS MORNING ACROSS SRN MN. WATER VAPOR IMAGERY SHOWS MID
LEVEL DRY SLOT MOVING ACROSS IA AND INTO SW WI WITH A BAROCLINIC
LEAF WITH COOLING IR TEMPS STARTING TO OVERTAKE SRN MN. AT 3 AM SFC
FREEZING ALONG WITH SNOW LINE STRETCHED FROM NEW ULM UP INTO ST.
CLOUD. BESIDE SFC TEMPS BEING ABOVE FREEZING EAST OF ULM/STC...RAP
SOUNDINGS STILL SHOW A MELTING LAYER EXISTING BETWEEN H8-H7...HENCE
THE RAPL MIX SEEN OFF AND ON THROUGH THE EVENING HERE IN CHANHASSEN
AND OBSERVED AT MSP. HOWEVER...AS PRECIP INTENSITY CONTINUES TO
INCREASE THIS MORNING EXPECT THE SNOW LINE TO WORK EAST TO NEAR A
MANKATO/HASTINGS/RICE LAKE LINE AROUND DAYBREAK. THIS ERN SHIFT WILL
OCCUR FOR TWO REASONS. ONE...THOUGH AIR TEMPS MAY BE IN THE MID
30S...DEWPOINTS ARE ABOUT 10 DEGREES COOLER...SO WET BULBING EFFECTS
SHOULD START TO QUICKLY TAKE OVER THIS MORNING AND QUICKLY COOL SFC
TEMPS BELOW FREEZING ACROSS ALMOST THE ENTIRE AREA. FOR THE WARM
NOSE...IT WILL BE BEATEN BACK TO THE EAST AS STRONG LIFT IN THE
H8-H7 LAYER CAUSES IT TO COOL BACK BELOW FREEZING.
SO FAR THIS MORNING...THE SIOUX FALLS AREA PICKED UP 4-5 INCHES OF
SNOW...AND THAT WAS AS THIS BAND WAS JUST STARTING TO PICK UP IN
INTENSITY...SO STILL LOOKS GOOD TO SEE SOME RATHER RAPID AND
SIGNIFICANT SNOW ACCUMULATIONS NOW THROUGH ABOUT NOON. EXACTLY HOW
THAT WARM NOSE BREAKS DOWN IS WHAT WILL PLAY A LARGE ROLL IN HOW
MUCH SNOW IS SEEN THIS MORNING. SPREAD FOR WHERE THE SNOW LINE ENDS
UP THIS MORNING STILL SITS ANYWHERE FROM NEW ULM UP THROUGH MORA ON
THE RAP TO ALBERT LEA UP THROUGH LADYSMITH ON THE GEM...SO DESPITE
THE MAIN EVENT STARTING TO COMMENCE...A FAIR AMOUNT OF UNCERTAINTY
STILL EXISTS AS TO HOW MUCH SNOW THE TWIN CITIES GETS THIS MORNING.
THE RAP WOULD SAY 1 TO 3 INCHES AT BEST...WHILE THE GEM SOLUTION FOR
WHERE THE SNOW LINE ENDS UP WOULD PUT THE TWIN CITIES IN LINE FOR
DOUBLE DIGIT AMOUNTS. FOR THIS FORECAST FAVORED SOMETHING IN BETWEEN
WITH THE SNOW LINE MAKING IT TO NEAR THE MANKATO/HASTINGS/RICE LAKE
LINE MENTIONED EARLIER.
ALL MODELS SHOW THIS BAND QUICKLY LIFTING NORTH THOUGH THE MORNING
WITH IT MOSTLY NORTH OF THE MPX CWA BY 18Z. WHAT HAPPENS IN THE WAKE
OF THE HEAVY BAND IS STILL VERY DEBATABLE AT THE MOMENT. BASED ON
SOUNDINGS...CURRENT THINKING AS THAT MUCH OF THE AREA WILL LOSE ICE
IN THE CLOUDS...WITH DZ/FZDZ TAKING OVER FOR MUCH OF THE AFTERNOON
OUTSIDE OF WRN MN. ALREADY SEEING THIS ACROSS WRN IA...WHERE SEVERAL
SITES SOUTH OF THE COLD CLOUD TOPS NOW REPORTING DZ. TRIED TO
INCORPORATE THIS INTO THE GRIDS AS BEST AS POSSIBLE...BUT THIS WILL
NEED TO BE REFINED DURING THE MORNING.
FOR TONIGHT...AS THE UPPER LOW SLOWLY MOVES EAST ACROSS IA...WILL
SEE MID LEVEL MOISTURE FILL BACK IN FROM WEST TO EAST. FOLLOWED THE
IDEA OF THE 00Z NAM...WITH SNOW QUICKLY RETURNING TO MN BETWEEN 21Z
AND 00Z...WITH WI TRANSITION BACK TO SNOW BETWEEN 00Z AND 03Z AND
ICE GETS REINTRODUCED INTO THE CLOUDS. AFTER THAT...WILL BE IN MOIST
CYCLONIC FLOW THROUGH THE NIGHT...WITH PERIODS OF LIGHT SNOW
CONTINUING. HEAVIEST AMOUNTS TONIGHT ARE EXPECTED ACROSS WI...BUT
EVEN THERE...ONLY ANTICIPATING AN EXTRA 1-2 INCHES OF SNOW AS LIFT
AND DYNAMICS WILL BE CONSIDERABLY WEAKER THAN WHAT IS CURRENTLY
UNFOLDING.
AS FOR THE HEADLINES...SEE NO NEED FOR CHANGES...WITH GREATER THAN 6
INCHES OF SNOW STILL EXPECTED WEST OF A MANKATO/HASTINGS/RICE LAKE
LINE...WITH THE COMBINATION OF FZRA/IP/SN EAST OF THERE SUPPORTING
THE WARNING ACROSS EASTERN AREAS.
.LONG TERM...(FRIDAY MORNING THROUGH WEDNESDAY)
ISSUED AT 415 AM CDT THU APR 11 2013
CONTINUED COOL AND RATHER WET PATTERN INTO END OF PERIOD. CURRENT
SURFACE AND 50H LOW PRESSURE SYSTEM BECOMES ALMOST VERTICALLY
STACKED BY EARLY FRIDAY MORNING. ENERGY WRAPPING AROUND MID LEVEL
LOW AND COLD POOL ASSOCIATED WITH SAME JUSTIFIED FAIRLY HIGH POPS
OVER EASTERN THIRD OF CWA FRIDAY MORNING INTO THE AFTERNOON.
1000-500MB THICKNESS VALUES ASSURING ALL ACTIVITY WILL FALL AS
LIGHT SNOW. 50H LOW WILL MAKE A VERY SLOW EXIT INTO NORTHERN GREAT
LAKES REGION BY SATURDAY MORNING. ANY LINGERING SLT POPS OVER
WEST CENTRAL WI WILL END AS THIS OCCURS.
VERY SHORT DRY WINDOW OPENS UP OVER MUCH OF FA FOR MUCH OF MORNING
AND ALL OF THE AFTN HOURS. ZONAL FLOW REESTABLISHES ITSELF OVER
WESTERN HALF OF NORTHERN CONUS. THIS WILL USHER IN NEXT MID PACIFIC
STORM SYSTEM CURRENTLY SITUATED OVER GULF OF ALASKA. WARM FRONTAL
BOUNDARY ASSOCIATED WITH THIS SYSTEM WILL BEGIN TO AFFECT SW CWA
SATURDAY EVENING AND THEN OVERSPREAD ALL COUNTIES BY SUNDAY MORNING.
COULD BE A SHORT BOUT OF FREEZING RAIN OR DRIZZLE LATE SATURDAY NIGHT
OVER PORTION OF SW CWA ROUGHLY SW OF LINE FROM MORRIS TO BLUE EARTH.
CHANGEOVER TO ALL RAIN THIS REGION SHOULD OCCUR FAIRLY SOON AFTER
11 OR 12Z TIME FRAME. 850MB TEMPS TRANSITIONS SNOW OR A RAIN SNOW
MIX ACROSS REMAINDER OF CWA BY SATURDAY 18Z. SURFACE LOW PRESSURE
ASSOCIATED WITH THIS STORM SYSTEM WILL BE MUCH DEEPER (995MB)
...COMPARED TO CURRENT ONE...BUT UNFORTUNATELY ANOTHER SLOW MOVING
50H LOW WILL FORM WITH IT AND BOTH BECOME STACKED BY 15/06Z TIME
FRAME. TRACK INTO NORTHERN GREAT LAKES REGION WILL OCCUR BY
MONDAY EVENING.
DEEP MID LEVEL TROUGH BEGINS TO DIG OVER WESTERN CONUS BY TUESDAY
AFTN. BY WED AFTN 50H TROF WILL BE OBSERVED FROM NE NEW MEXICO
TO NW MN BY WED AFTN. PROGRESSION OF THIS TROF SLOWLY EASTWARD
GENERATES CHANCE PCPN ON BOTH WED AND THURSDAY. ATMOSPHERE STILL
LOOKS COLD ENOUGH TO INCLUDE EITHER A RAIN/SNOW MIX OR LIGHT SNOW
OVER MUCH OF FA BOTH DAYS.
INTO NEXT WEEKEND EXPECT ZONAL NORTHERN U.S. FLOW TO CONTINUE
UPSTREAM OF OUR LOCATION WITH ANOTHER MID PACIFIC STORM SYSTEM
BRINGING ANOTHER CHANCE FOR PCPN TO THE UPPER MIDWEST FRIDAY NIGHT
INTO SATURDAY. TEMPERATURES WILL CONTINUE THEIR PERSISTENT TREND
OF REMAINING ABOUT 10 DEGREES BELOW NORMAL INTO NEXT WEEKEND.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 734 AM CDT THU APR 11 2013
HEAVY SNOW WELL UNDERWAY ACROSS MN...BUT BACK EDGE OF HEAVY PRECIP
ALREADY WORKING NORTH OUT OF SW/SC MN. HAVE THIS BACK EDGE OF SUB
1SM SNOW TIMED TO CLEAR RWF BY 13Z...MSP AROUND 14Z AND STC/AXN
BETWEEN 15Z AND 16Z. FOR WI...WITH DRY SLOT HEADING FOR CENTRAL
WI...RATES/AMOUNTS WILL BE LESS THERE...WITH EAU LIKELY TO SEE A
MAINLY RA/PL MIX WITH LIMITED SNOW. CONFIDENCE DOES DECREASE IN
PRECIP/VIS FORECAST AFTER THIS MORNINGS PRECIP BURST MOVES NORTH
OF THE AREA. INDICATIONS FROM THE NAM/RAP ARE THAT WE LOOSE ICE IN
THE CLOUDS EAST OF RWF/AXN...WITH PRIMARILY DZ EXPECTED THIS
AFTERNOON ACROSS ERN MN INTO WRN WI. VIS RESTRICTIONS MAY ALSO NOT
BE AS BAD AS CURRENTLY INDICATED...WITH PRECIP POSSIBLY JUST
CUTTING OF ALL TOGETHER THIS AFTERNOON...BUT CIGS LOOK TO REMAIN
FIRMLY IN THE IFR RANGE AS TERMINALS REMAIN JUST NORTH OF AN
INVERTED THROUGH. TONIGHT...AS DRY SLOT PUSHES EAST...DEEP
MOISTURE RETURNS...WITH ANY REMAINING PRECIP EXPECTED TO GO BACK
TO SNOW. BEST CHANCE FOR MORE PERSISTENT SNOWS OVERNIGHT WILL
SHIFT TO WRN WI. FINALLY...WINDS HAVE BEEN BEHAVING A BIT
UNEXPECTEDLY THIS MORNING...WITH HEAVY SNOW APPEARING TO
SIGNIFICANTLY DAMPEN WIND SPEEDS...THOUGH DO EXPECT THEM TO PICK
BACK UP FROM WHERE THEY LEFT OFF ONCE HEAVY SNOW MOVES OUT.
KMSP...STRONG SHORT TERM MODEL AGREEMENT WITH CURRENT BOUT OF
HEAVY SNOW QUICKLY SHUTTING OFF AROUND 14Z. CONFIDENCE DOES
DECREASE CONSIDERABLY IN PRECIP FORECAST AFTER ABOUT 15Z AS
MOISTURE IN THE SNOW GROWTH ZONE DEPARTS. SEE ONE OF TWO THINGS
HAPPENING. ONE...PRECIP ENDS WITH HEAVY SNOW...WITH NOTHING MORE
THAN FEW PASSING SPRINKLES. TWO...DZ OR A DZSN COMBO TAKES OVER
FOR THE REST OF THE AFTERNOON. OPTION ONE WOULD RESULT IN MAINLY
VFR VIS...WITH OPTION 2 KEEPING MAINLY MVFR VSBYS GOING. NO MATTER
WHAT HAPPENS WITH PRECIP...HARD PRESSED TO SEE CIGS LEAVING THE
IFR CATEGORY UNTIL FRIDAY MORNING. FOR WINDS...EXPECT THE NE WINDS
TO PICK BACK UP IN STRENGTH AS SNOW DIMINISHES...WITH A GRADUAL
BACKING OF WINDS TOWARD THE NW LATE TONIGHT.
/OUTLOOK FOR KMSP/
FRI...MVFR CIGS. -SN ENDING IN MORNING. WINDS NW 10 KTS.
SAT...MAINLY VFR...WITH MVFR CONDS OVERNIGHT. POSSIBLE -RA/-SN
OVERNIGHT. WINDS S AROUND 5 KT.
SUN...MVFR EXPECTED WITH IFR POSSIBLE...MAINLY IN THE MORNING.
MORNING -RA/-SN THEN AFTERNOON -RA. SE WINDS AROUND 10
KT...BECOMING S.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR MNZ041>045-
047>070-073>078-082>085-091>093.
WI...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR WIZ014>016-
023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
415 AM CDT THU APR 11 2013
.SHORT TERM...(TODAY THROUGH THURSDAY MORNING)
WELL ADVERTISED PRECIPITATION BURST FINALLY STARTING TO COME
TOGETHER THIS MORNING ACROSS SRN MN. WATER VAPOR IMAGERY SHOWS MID
LEVEL DRY SLOT MOVING ACROSS IA AND INTO SW WI WITH A BAROCLINIC
LEAF WITH COOLING IR TEMPS STARTING TO OVERTAKE SRN MN. AT 3 AM SFC
FREEZING ALONG WITH SNOW LINE STRETCHED FROM NEW ULM UP INTO ST.
CLOUD. BESIDE SFC TEMPS BEING ABOVE FREEZING EAST OF ULM/STC...RAP
SOUNDINGS STILL SHOW A MELTING LAYER EXISTING BETWEEN H8-H7...HENCE
THE RAPL MIX SEEN OFF AND ON THROUGH THE EVENING HERE IN CHANHASSEN
AND OBSERVED AT MSP. HOWEVER...AS PRECIP INTENSITY CONTINUES TO
INCREASE THIS MORNING EXPECT THE SNOW LINE TO WORK EAST TO NEAR A
MANKATO/HASTINGS/RICE LAKE LINE AROUND DAYBREAK. THIS ERN SHIFT WILL
OCCUR FOR TWO REASONS. ONE...THOUGH AIR TEMPS MAY BE IN THE MID
30S...DEWPOINTS ARE ABOUT 10 DEGREES COOLER...SO WET BULBING EFFECTS
SHOULD START TO QUICKLY TAKE OVER THIS MORNING AND QUICKLY COOL SFC
TEMPS BELOW FREEZING ACROSS ALMOST THE ENTIRE AREA. FOR THE WARM
NOSE...IT WILL BE BEATEN BACK TO THE EAST AS STRONG LIFT IN THE
H8-H7 LAYER CAUSES IT TO COOL BACK BELOW FREEZING.
SO FAR THIS MORNING...THE SIOUX FALLS AREA PICKED UP 4-5 INCHES OF
SNOW...AND THAT WAS AS THIS BAND WAS JUST STARTING TO PICK UP IN
INTENSITY...SO STILL LOOKS GOOD TO SEE SOME RATHER RAPID AND
SIGNIFICANT SNOW ACCUMULATIONS NOW THROUGH ABOUT NOON. EXACTLY HOW
THAT WARM NOSE BREAKS DOWN IS WHAT WILL PLAY A LARGE ROLL IN HOW
MUCH SNOW IS SEEN THIS MORNING. SPREAD FOR WHERE THE SNOW LINE ENDS
UP THIS MORNING STILL SITS ANYWHERE FROM NEW ULM UP THROUGH MORA ON
THE RAP TO ALBERT LEA UP THROUGH LADYSMITH ON THE GEM...SO DESPITE
THE MAIN EVENT STARTING TO COMMENCE...A FAIR AMOUNT OF UNCERTAINTY
STILL EXISTS AS TO HOW MUCH SNOW THE TWIN CITIES GETS THIS MORNING.
THE RAP WOULD SAY 1 TO 3 INCHES AT BEST...WHILE THE GEM SOLUTION FOR
WHERE THE SNOW LINE ENDS UP WOULD PUT THE TWIN CITIES IN LINE FOR
DOUBLE DIGIT AMOUNTS. FOR THIS FORECAST FAVORED SOMETHING IN BETWEEN
WITH THE SNOW LINE MAKING IT TO NEAR THE MANKATO/HASTINGS/RICE LAKE
LINE MENTIONED EARLIER.
ALL MODELS SHOW THIS BAND QUICKLY LIFTING NORTH THOUGH THE MORNING
WITH IT MOSTLY NORTH OF THE MPX CWA BY 18Z. WHAT HAPPENS IN THE WAKE
OF THE HEAVY BAND IS STILL VERY DEBATABLE AT THE MOMENT. BASED ON
SOUNDINGS...CURRENT THINKING AS THAT MUCH OF THE AREA WILL LOSE ICE
IN THE CLOUDS...WITH DZ/FZDZ TAKING OVER FOR MUCH OF THE AFTERNOON
OUTSIDE OF WRN MN. ALREADY SEEING THIS ACROSS WRN IA...WHERE SEVERAL
SITES SOUTH OF THE COLD CLOUD TOPS NOW REPORTING DZ. TRIED TO
INCORPORATE THIS INTO THE GRIDS AS BEST AS POSSIBLE...BUT THIS WILL
NEED TO BE REFINED DURING THE MORNING.
FOR TONIGHT...AS THE UPPER LOW SLOWLY MOVES EAST ACROSS IA...WILL
SEE MID LEVEL MOISTURE FILL BACK IN FROM WEST TO EAST. FOLLOWED THE
IDEA OF THE 00Z NAM...WITH SNOW QUICKLY RETURNING TO MN BETWEEN 21Z
AND 00Z...WITH WI TRANSITION BACK TO SNOW BETWEEN 00Z AND 03Z AND
ICE GETS REINTRODUCED INTO THE CLOUDS. AFTER THAT...WILL BE IN MOIST
CYCLONIC FLOW THROUGH THE NIGHT...WITH PERIODS OF LIGHT SNOW
CONTINUING. HEAVIEST AMOUNTS TONIGHT ARE EXPECTED ACROSS WI...BUT
EVEN THERE...ONLY ANTICIPATING AN EXTRA 1-2 INCHES OF SNOW AS LIFT
AND DYNAMICS WILL BE CONSIDERABLY WEAKER THAN WHAT IS CURRENTLY
UNFOLDING.
AS FOR THE HEADLINES...SEE NO NEED FOR CHANGES...WITH GREATER THAN 6
INCHES OF SNOW STILL EXPECTED WEST OF A MANKATO/HASTINGS/RICE LAKE
LINE...WITH THE COMBINATION OF FZRA/IP/SN EAST OF THERE SUPPORTING
THE WARNING ACROSS EASTERN AREAS.
.LONG TERM...(FRIDAY MORNING THROUGH WEDNESDAY)
CONTINUED COOL AND RATHER WET PATTERN INTO END OF PERIOD. CURRENT
SURFACE AND 50H LOW PRESSURE SYSTEM BECOMES ALMOST VERTICALLY
STACKED BY EARLY FRIDAY MORNING. ENERGY WRAPPING AROUND MID LEVEL
LOW AND COLD POOL ASSOCIATED WITH SAME JUSTIFIED FAIRLY HIGH POPS
OVER EASTERN THIRD OF CWA FRIDAY MORNING INTO THE AFTERNOON.
1000-500MB THICKNESS VALUES ASSURING ALL ACTIVITY WILL FALL AS
LIGHT SNOW. 50H LOW WILL MAKE A VERY SLOW EXIT INTO NORTHERN GREAT
LAKES REGION BY SATURDAY MORNING. ANY LINGERING SLT POPS OVER
WEST CENTRAL WI WILL END AS THIS OCCURS.
VERY SHORT DRY WINDOW OPENS UP OVER MUCH OF FA FOR MUCH OF MORNING
AND ALL OF THE AFTN HOURS. ZONAL FLOW REESTABLISHES ITSELF OVER
WESTERN HALF OF NORTHERN CONUS. THIS WILL USHER IN NEXT MID PACIFIC
STORM SYSTEM CURRENTLY SITUATED OVER GULF OF ALASKA. WARM FRONTAL
BOUNDARY ASSOCIATED WITH THIS SYTEM WILL BEGIN TO AFFECT SW CWA
SATURDAY EVENING AND THEN OVERSPREAD ALL COUNTIES BY SUNDAY MORNING.
COULD BE A SHORT BOUT OF FREEZING RAIN OR DRIZZLE LATE SATURDAY NIGHT
OVER PORTION OF SW CWA ROUGHLY SW OF LINE FROM MORRIS TO BLUE EARTH.
CHANGEOVER TO ALL RAIN THIS REGION SHOULD OCCUR FAIRLY SOON AFTER
11 OR 12Z TIME FRAME. 850MB TEMPS TRANSITIONS SNOW OR A RAIN SNOW
MIX ACROSS REMAINDER OF CWA BY SATURDAY 18Z. SURFACE LOW PRESSURE
ASSOCIATED WITH THIS STORM SYSTEM WILL BE MUCH DEEPER (995MB)
...COMPARED TO CURRENT ONE...BUT UNFORTUNATELY ANOTHER SLOW MOVING
50H LOW WILL FORM WITH IT AND BOTH BECOME STACKED BY 15/06Z TIME
FRAME. TRACK INTO NORTHERN GREAT LAKES REGION WILL OCCUR BY
MONDAY EVENING.
DEEP MID LEVEL TROUGH BEGINS TO DIG OVER WESTERN CONUS BY TUESDAY
AFTN. BY WED AFTN 50H TROF WILL BE OBSERVED FROM NE NEW MEXICO
TO NW MN BY WED AFTN. PROGRESSION OF THIS TROF SLOWLY EASTWARD
GENERATES CHANCE PCPN ON BOTH WED AND THURSDAY. ATMOSPHERE STILL
LOOKS COLD ENOUGH TO INCLUDE EITHER A RAIN/SNOW MIX OR LIGHT SNOW
OVER MUCH OF FA BOTH DAYS.
INTO NEXT WEEKEND EXPECT ZONAL NORTHERN U.S. FLOW TO CONTINUE
UPSTREAM OF OUR LOCATION WITH ANOTHER MID PACIFIC STORM SYSTEM
BRINGING ANOTHER CHANCE FOR PCPN TO THE UPPER MIDWEST FRIDAY NIGHT
INTO SATURDAY. TEMPERATURES WILL CONTINUE THEIR PERSISTENT TREND
OF REMAINING ABOUT 10 DEGREES BELOW NORMAL INTO NEXT WEEKEND.
&&
.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 1201 AM CDT THU APR 11 2013
LITTLE CHANGE IN THINKING FROM 11/00Z TAFS EXCEPT FOR MAINLY
DURING THE FIRST FEW HOURS FROM 11/06Z ONWARD AS PRECIP HAS BEEN A
BIT SLOWER TO DEVELOP. HOWEVER...CURRENTLY KMPX RADAR SHOWS PLENTY
OF DEVELOPING AREAS OF PRECIPITATION...PREDOMINANTLY AS A WINTRY
MIX. THIS MIX WILL CONTINUE TO OVERSPREAD THE AREA AND CHANGE OVER
TO -SN BY 08Z-09Z. THE MAIN CONCERN THEN BECOMES PRECIP INTENSITY
AS SHORT-TERM MODELS STILL PIN DOWN THE 09Z-14Z TIMEFRAME WHEN
INTENSITY AND QPF WILL BE GREATEST. SOME SNOWFALL RATES MAY BE AS
HIGH AS 2-3 IN/HR FOR A BRIEF PERIOD AFTER SUNRISE SO HAVE HIT
THIS IN THE TAF WITH VSBY BETWEEN 1/2SM-1SM. PRECIP THEN LESSENS
IN INTENSITY LATE MRNG THRU THE AFTN...BUT DIFFICULT TO DISCERN
WHERE THERE MAY BE SOME DRY SLOTTING WHICH WOULD IMPROVE VSBY WITH
MUCH LIGHTER PRECIP. THEN...THERE WILL BE ANOTHER SURGE OF
MOISTURE AS THE SYSTEM EXITS WHICH MAY BRING A RETURN OF STRONGER
-SN ON THE BACKSIDE OF THE DEPARTING LOW PRES SYSTEM. CEILINGS
OVERALL TAKE A DIVE DOWN TO IFR AND REMAIN THERE THRU MUCH OF THE
DAY...THOUGH THERE MAY WELL BE OCNL PERIODS WHEN CIGS BOUNCE
UPWARDS INTO LOW-END MVFR. AS FOR THE WINDS...SPEEDS WILL
GENERALLY REACH 15G25KT THROUGH MUCH OF THE OVERNIGHT HOURS AND
THUR. DIRECTIONS WILL BE A BIT PROBLEMATIC...BUT PREVAILING
DIRECTIONS ON AVAILABLE MOS GUIDANCE IS IN THE 040-060 RANGE.
KMSP...TWO MAIN ISSUES WILL BE SNOWFALL INTENSITY ALONG WITH WIND
DIRECTIONS. PATCHY -RASN ARND MSP DURING THE EARLY MRNG HRS WILL
BECOME MORE WIDESPREAD AND CHANGE OVER TO -SN...APPROXIMATELY BY
11/08Z. SNOWFALL WILL THEN PICK UP IN INTENSITY THROUGH THE EARLY
MRNG HOURS...POSSIBLY HEAVY AT TIMES BETWEEN 09Z-13Z...RIGHT
THROUGH THE MRNG PUSH. VSBY MAY WELL DROP AS LOW AS 1/2SM BUT
CONFIDENCE IS HIGH IN SEEING VSBY LESS THAN 1SM. SNOWFALL THEN
LOOKS TO LESSEN IN INTENSITY BY LATE MRNG...GRADUALLY ALLOWING
VSBY TO RISE INTO MVFR RANGE. NEVERTHELESS...CEILINGS WILL BE
SOLIDLY IN IFR RANGE IF NOT LOWER FOR MUCH OF THE EVENT. AS FOR
WIND DIRECTIONS...AM HAVING A HARD TIME SEEING ANYTHING OTHER THAN
050-060 DIRECTION...WITH OCCASIONAL 040 BUT NOT LIKELY TO SEE 070.
FOR AROUND THE MORNING PUSH...WILL LOOK FOR PREDOMINANTLY 050.
SPEEDS WILL REMAIN ARND 15G25KT THROUGHOUT THIS TAF PERIOD.
/OUTLOOK FOR KMSP/
FRI...MVFR CIGS. -SN ENDING IN MORNING. WINDS NW 10 KTS.
SAT...MAINLY VFR...WITH MVFR CONDS OVERNIGHT. POSSIBLE -RA/-SN
OVERNIGHT. WINDS S AROUND 5 KT.
SUN...MVFR EXPECTED WITH IFR POSSIBLE...MAINLY IN THE MORNING.
MORNING -RA/-SN THEN AFTERNOON -RA. SE WINDS AROUND 10
KT...BECOMING S.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR MNZ041>045-
047>070-073>078-082>085-091>093.
WI...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR WIZ014>016-
023>028.
&&
$$
SHORT TERM...MPG
LONG TERM...AZ
AVIATION...MPG
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1041 AM EDT THU APR 11 2013
.SYNOPSIS...
UNSETTLED CONDITIONS WILL PREVAIL INTO SATURDAY AS A COMPLEX AREA
OF LOW PRESSURE MOVES FROM THE GREAT LAKES INTO THE NORTHEAST.
SHOWERS...POSSIBLY MIXED WITH SLEET OVER PORTIONS OF CENTRAL NEW
YORK...CAN BE EXPECTED INTO FRIDAY...WITH SCATTERED RAIN OR SNOW
SHOWERS PERSISTING INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE... WE`VE TIGHTENED UP THE POP/WX GRIDS FOR THE REST
OF THE DAY INTO THIS EVE...OTHWS NO SIG CHGS ATTM.
ON THE LARGE-SCALE...E-W ORIENTED BNDRY ACRS PA CONTS TO SINK
FURTHER S ATTM...AS EVIDENCED BY THE SWD ADVANCEMENT OF THE LWR
CLOUD MASS. IN THE MEANTIME...THE "WARM FRNT ALOFT (ARND 850 MB)"
IS SITUATED ACRS NY STATE...WITH THE STEADIER PCPN FOCUSED ALG AND
N OF THIS FEATURE. BASED ON RADAR COVERAGE UPSTREAM...AND THE
LIKELY PASSAGE OF ADDTNL UPR-LVL S/WVS...WE EXPECT STEADY...ALBEIT
FAIRLY LGT PCPN...TO CONTINUE UP N THROUGH THE DAY...AND RIGHT
INTO TNT. AS FAR AS PTYP IS CONCERNED...WE`VE HAD SOME OCNL SLEET
MIX WITH THE RAIN THIS AM ACRS SOME OF OUR FAR NRN AREAS...AND
THIS MAY ALSO PERSIST THIS AFTN. A LOOK AT THE 12Z ALY/BUF RAOBS
SHOWS A DISCERNIBLE SUB-FRZG LYR BETWEEN ABT 1500 AND 4000 FT AGL.
THERE`S ALSO PLENTY OF COLD DRY AIR JUST TO OUR N...CONTINUING TO
TRY TO FEED INTO THE RGN. FORTUNATELY...SFC TEMPS ARE GENERALLY
ABV FRZG...AND GIVEN TIME OF DAY AND YEAR...WE EXPECT THIS WILL
CONTINUE TO BE THE CASE THIS AFTN...MITIGATING ANY FZRA POTENTIAL.
FARTHER S...PCPN WILL BE MUCH LGTR AND MORE SPOTTY THROUGH THE SRN TIER
OF NY...WITH DRY WX BASICALLY FORESEEN ACRS NE PA/SULLIVAN NY.
TEMPS MAY GO UP A FEW MORE DEGS THROUGH EARLY AFTN...BUT WE DON`T
EXPECT MUCH CHG FROM PRESENT READINGS...WITH LOW-LVL CAA AT PLAY N
OF THE ABV MENTIONED SFC FRNT.
620 AM UPDATE... TD`S HAVE FALLEN INTO THE L/M30S ACRS THE FINGER
LAKES AND CNTRL SRN TIER...WITH M20S JUST S OF LAKE ONTARIO. POTNL
FOR SOME PL THIS MRNG AS BAND OF SHRA ENTERS THESE AREAS. SIG
DIFFS IN THE PROFILES FOR NRN ONEIDA W/RESPECT TO A MIX LATER TDA
AND TNGT BUT WITH LOW CONFIDENCE WILL LET DAY SHIFT TAKE A CLOSER
LOOK AT THE 12Z DATA. PREV BLO...
NOT MUCH CHG FROM PREV FCST. INITIAL LOOK AT MDL GUIDANCE
APPEARED TO SHOW A COOL BIAS AT F06 W/RESPECT TO T/TD`S. GROUND
TEMPS WILL BE RELATIVELY WARM...AND WE DON`T SEE SFC TEMPS OR SFC
WET BULBS GETTING BLO 32F THIS MRNG...REDUCING OR ELIMINATING ANY
FZRA THREAT. THIS HAS BEEN REFLECTED IN THE LATEST WWD GUIDANCE
WHICH LOOKS GOOD FROM OUR PERSPECTIVE. POPS INCRSNG FROM SW TO NE
AS NXT BATCH OF SHRA MOVS BACK INTO THE RGN. KEPT POTNL FOR SOME
SLEET TO MIX IN WITH THE RAIN ACRS PORTIONS OF THE CNTRL SRN TIER
AND FINGER LAKES...AND NRN ONEIDA.
FVRBL JET CONFIGURATION TNGT WITH FCST AREA IN RR QUAD OF THE 250
MB JET...COUPLED WITH A 50 KT SRLY 850 JET. GOOD ISEN LIFT TNGT
INTO FRI AHEAD OF THE OCCLUDED FNT. COOLEST AIR WILL RESIDE ACRS
ERN ZONES...BUT MDLS AGAIN MAY BE OVERDONE WITH THE LOW LVL COOL
AIR. RETAINED POTNL FOR SOME SLEET FROM NRN ONEIDA INTO THE WRN
CATSKILLS. COULD GET FAIRLY GUSTY TNGT...SPCLY HIGHER
ELEVATIONS...AS SELY FLOW INCRS.
WE`LL PRBLY SEE A GOOD 3/4 TO ONE INCH OF RAIN THU NGT INTO
FRI. WE SHOULD BE ABLE TO HANDLE THESE AMTS...BUT A FEW MAIN STEM
POINTS MAY APRCH CAUTION STAGE.
LASTLY...CAN`T RULE OUT ISOLD TSRA THIS AFTN OR TNGT...SPCLY ACRS
PA...BUT WILL JUST GO WITH SHRA FOR NOW AND LET LATER UPDATES ADD
MENTION IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
OCCLUDED FNT PASSES ON FRI...WITH BATCH OF RAIN XPCTD TO MOV OUT
OF ERN ZONES FRI AFTN. MAIN UPR TROF REMAINS OVER THE
GTLAKES...AND S/WV`S EMBEDDED IN THE SWLY FLOW ACRS NY/PA COULD
TRIGGER SCT -SHRA...WITH POTNL FOR -SHSN LATER AT NGT. A WEAK WAVE
IS EXPECTED TO PASS FRI NGT...WITH A STRONGER S/WV ON SAT.
RETAINED CHC POPS MAINLY ACRS CNTRL NY AND NRN PA...WITH ONLY SLGT
CHC POPS FAR SE ZONES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US LIFTS EARLY IN
THE LONG TERM. NW FLOW CONTINUES SAT NGT TO SUN SO POSSIBLY
FLURRIES AND SPRINKLES. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR LATE SUNDAY BEFORE A WARM FRONT LIFTS NE WITH RAIN FOR THE
AREA STARTING SUN NGT. ONCE AGAIN THIS FRONT WILL STALL ACROSS THE
AREA UNTIL WED WHEN A COLD FRONT APPROACHES AHEAD OF A LARGE UL
TROF. MODELS MAY BE TOO FAST WITH THE COLD FRONT SO OFF AND ON
SHOWERS MOST LIKELY SCENARIO.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
7 AM UPDATE...
AVIATION FORECAST REMAINS DIFFICULT...DUE TO COMPLICATIONS OF
BATCHES OF SHOWERS MOVING ALONG A WAFFLING FRONTAL BOUNDARY IN OUR
VICINITY. LOW LEVEL DRY AIR COURTESY OF VEERING LIGHT FLOW
BETWEEN WAVES FOUND ITS WAY INTO KSYR-KRME...LIFTING CIGS VFR
THERE THIS MORNING. OTHER TERMINALS IFR TO LOW END MVFR...EVEN
LIFR FOR HILLTOP TERMINALS KBGM AND KITH. WEAK WAVE OF SHOWERS
MOVING THROUGH EARLY THIS MORNING WILL ACTUALLY SERVE TO STIR THE
CIG WHERE IT IS VERY LOW...MAINLY MVFR AS IT MOVES THROUGH.
ADDITIONAL WAVES WILL AFFECT THE REGION FROM MIDDAY THROUGH
EVENING...THE INDIVIDUAL TIMING OF WHICH IS CHALLENGING AND LOW
CONFIDENCE. THE ASSOCIATED NEARLY STATIONARY FRONT WILL THEN
EDGE NORTHWARD WITH TIME...PERHAPS GIVING KAVP-KELM-KBGM-KITH A
RELATIVE BREAK RAIN-WISE THIS EVENING...BUT POSITIONING OF
BOUNDARY WILL CONTINUE TO FAVOR RAIN THIS EVENING FOR KSYR-KRME.
SEVERAL TERMINALS WILL CONTINUE OR RETURN TO IFR CONDITIONS
TONIGHT...ESPECIALLY AS COLD FRONT OF SYSTEM MOVES INTO AREA
TOWARDS 12Z FRIDAY. WINDS THROUGH THE TAF PERIOD WILL BE LIGHT YET
VEERING WITH TIME...GENERALLY FROM A NORTHERLY DIRECTION THIS
MORNING TO AND EASTERLY ONE BY THIS EVENING...EVEN TOWARDS
SOUTHEAST OVERNIGHT TONIGHT. SEE TAFS FOR SPECIFICS.
.OUTLOOK...
FRI...MVFR WITH PDS OF IFR AS SHOWERY FRONT PASSES...ESPECIALLY
MORNING.
SAT AND SUN...VFR...PSBL MVFR IN MIXED SHWRS.
SUN NGT AND MON...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM/MDP/TAC
NEAR TERM...MLJ
SHORT TERM...
LONG TERM...TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
821 AM EDT THU APR 11 2013
.SYNOPSIS...
UNSETTLED CONDITIONS WILL PREVAIL INTO SATURDAY AS A COMPLEX AREA
OF LOW PRESSURE MOVES FROM THE GREAT LAKES INTO THE NORTHEAST.
SHOWERS...POSSIBLY MIXED WITH SLEET OVER PORTIONS OF CENTRAL NEW
YORK...CAN BE EXPECTED INTO FRIDAY...WITH SCATTERED RAIN OR SNOW
SHOWERS PERSISTING INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
620 AM UPDATE...
TD`S HAVE FALLEN INTO THE L/M30S ACRS THE FINGER LAKES AND CNTRL
SRN TIER...WITH M20S JUST S OF LAKE ONTARIO. POTNL FOR SOME PL THIS
MRNG AS BAND OF SHRA ENTERS THESE AREAS. SIG DIFFS IN THE PROFILES
FOR NRN ONEIDA W/RESPECT TO A MIX LATER TDA AND TNGT BUT WITH LOW
CONFIDENCE WILL LET DAY SHIFT TAKE A CLOSER LOOK AT THE 12Z DATA.
PREV BLO...
NOT MUCH CHG FROM
PREV FCST. INITIAL LOOK AT MDL GUIDANCE APPEARED TO SHOW A COOL
BIAS AT F06 W/RESPECT TO T/TD`S. GROUND TEMPS WILL BE RELATIVELY
WARM...AND WE DON`T SEE SFC TEMPS OR SFC WET BULBS GETTING BLO 32F
THIS MRNG...REDUCING OR ELIMINATING ANY FZRA THREAT. THIS HAS BEEN
REFLECTED IN THE LATEST WWD GUIDANCE WHICH LOOKS GOOD FROM OUR
PERSPECTIVE. POPS INCRSNG FROM SW TO NE AS NXT BATCH OF SHRA MOVS
BACK INTO THE RGN. KEPT POTNL FOR SOME SLEET TO MIX IN WITH THE
RAIN ACRS PORTIONS OF THE CNTRL SRN TIER AND FINGER LAKES...AND
NRN ONEIDA.
FVRBL JET CONFIGURATION TNGT WITH FCST AREA IN RR QUAD OF THE 250
MB JET...COUPLED WITH A 50 KT SRLY 850 JET. GOOD ISEN LIFT TNGT
INTO FRI AHEAD OF THE OCCLUDED FNT. COOLEST AIR WILL RESIDE ACRS
ERN ZONES...BUT MDLS AGAIN MAY BE OVERDONE WITH THE LOW LVL COOL
AIR. RETAINED POTNL FOR SOME SLEET FROM NRN ONEIDA INTO THE WRN
CATSKILLS. COULD GET FAIRLY GUSTY TNGT...SPCLY HIGHER
ELEVATIONS...AS SELY FLOW INCRS.
WE`LL PRBLY SEE A GOOD 3/4 TO ONE INCH OF RAIN THU NGT INTO
FRI. WE SHOULD BE ABLE TO HANDLE THESE AMTS...BUT A FEW MAIN STEM
POINTS MAY APRCH CAUTION STAGE.
LASTLY...CAN`T RULE OUT ISOLD TSRA THIS AFTN OR TNGT...SPCLY ACRS
PA...BUT WILL JUST GO WITH SHRA FOR NOW AND LET LATER UPDATES ADD
MENTION IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
OCCLUDED FNT PASSES ON FRI...WITH BATCH OF RAIN XPCTD TO MOV OUT
OF ERN ZONES FRI AFTN. MAIN UPR TROF REMAINS OVER THE
GTLAKES...AND S/WV`S EMBEDDED IN THE SWLY FLOW ACRS NY/PA COULD
TRIGGER SCT -SHRA...WITH POTNL FOR -SHSN LATER AT NGT. A WEAK WAVE
IS EXPECTED TO PASS FRI NGT...WITH A STRONGER S/WV ON SAT.
RETAINED CHC POPS MAINLY ACRS CNTRL NY AND NRN PA...WITH ONLY SLGT
CHC POPS FAR SE ZONES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US LIFTS EARLY IN
THE LONG TERM. NW FLOW CONTINUES SAT NGT TO SUN SO POSSIBLY
FLURRIES AND SPRINKLES. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR LATE SUNDAY BEFORE A WARM FRONT LIFTS NE WITH RAIN FOR THE
AREA STARTING SUN NGT. ONCE AGAIN THIS FRONT WILL STALL ACROSS THE
AREA UNTIL WED WHEN A COLD FRONT APPROACHES AHEAD OF A LARGE UL
TROF. MODELS MAY BE TOO FAST WITH THE COLD FRONT SO OFF AND ON
SHOWERS MOST LIKELY SCENARIO.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
7 AM UPDATE...
AVIATION FORECAST REMAINS DIFFICULT...DUE TO COMPLICATIONS OF
BATCHES OF SHOWERS MOVING ALONG A WAFFLING FRONTAL BOUNDARY IN OUR
VICINITY. LOW LEVEL DRY AIR COURTESY OF VEERING LIGHT FLOW
BETWEEN WAVES FOUND ITS WAY INTO KSYR-KRME...LIFTING CIGS VFR
THERE THIS MORNING. OTHER TERMINALS IFR TO LOW END MVFR...EVEN
LIFR FOR HILLTOP TERMINALS KBGM AND KITH. WEAK WAVE OF SHOWERS
MOVING THROUGH EARLY THIS MORNING WILL ACTUALLY SERVE TO STIR THE
CIG WHERE IT IS VERY LOW...MAINLY MVFR AS IT MOVES THROUGH.
ADDITIONAL WAVES WILL AFFECT THE REGION FROM MIDDAY THROUGH
EVENING...THE INDIVIDUAL TIMING OF WHICH IS CHALLENGING AND LOW
CONFIDENCE. THE ASSOCIATED NEARLY STATIONARY FRONT WILL THEN
EDGE NORTHWARD WITH TIME...PERHAPS GIVING KAVP-KELM-KBGM-KITH A
RELATIVE BREAK RAIN-WISE THIS EVENING...BUT POSITIONING OF
BOUNDARY WILL CONTINUE TO FAVOR RAIN THIS EVENING FOR KSYR-KRME.
SEVERAL TERMINALS WILL CONTINUE OR RETURN TO IFR CONDITIONS
TONIGHT...ESPECIALLY AS COLD FRONT OF SYSTEM MOVES INTO AREA
TOWARDS 12Z FRIDAY. WINDS THROUGH THE TAF PERIOD WILL BE LIGHT YET
VEERING WITH TIME...GENERALLY FROM A NORTHERLY DIRECTION THIS
MORNING TO AND EASTERLY ONE BY THIS EVENING...EVEN TOWARDS
SOUTHEAST OVERNIGHT TONIGHT. SEE TAFS FOR SPECIFICS.
.OUTLOOK...
FRI...MVFR WITH PDS OF IFR AS SHOWERY FRONT PASSES...ESPECIALLY
MORNING.
SAT AND SUN...VFR...PSBL MVFR IN MIXED SHWRS.
SUN NGT AND MON...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM/MDP/TAC
NEAR TERM...
SHORT TERM...
LONG TERM...TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
723 AM EDT THU APR 11 2013
.SYNOPSIS...
UNSETTLED CONDITIONS WILL PREVAIL INTO SATURDAY AS A COMPLEX AREA OF
LOW PRESSURE MOVES FROM THE GREAT LAKES INTO THE NORTHEAST.
SHOWERS...POSSIBLY MIXED SLEET OVER PORTIONS OF CENTRAL NEW
YORK...CAN BE EXPECTED INTO FRIDAY...WITH SCATTERED RAIN OR SNOW
SHOWERS PERSISTING INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
620 AM UPDATE...
TD`S HAVE FALLEN INTO THE L/M30S ACRS THE FINGER LAKES AND CNTRL
SRN TIER...WITH M20S JUST S OF LAKE ONTARIO. POTNL FOR SOME PL THIS
MRNG AS BAND OF SHRA ENTERS THESE AREAS. SIG DIFFS IN THE PROFILES
FOR NRN ONEIDA W/RESPECT TO A MIX LATER TDA AND TNGT BUT WITH LOW
CONFIDENCE WILL LET DAY SHIFT TAKE A CLOSER LOOK AT THE 12Z DATA.
PREV BLO...
NOT MUCH CHG FROM
PREV FCST. INITIAL LOOK AT MDL GUIDANCE APPEARED TO SHOW A COOL
BIAS AT F06 W/RESPECT TO T/TD`S. GROUND TEMPS WILL BE RELATIVELY
WARM...AND WE DON`T SEE SFC TEMPS OR SFC WET BULBS GETTING BLO 32F
THIS MRNG...REDUCING OR ELIMINATING ANY FZRA THREAT. THIS HAS BEEN
REFLECTED IN THE LATEST WWD GUIDANCE WHICH LOOKS GOOD FROM OUR
PERSPECTIVE. POPS INCRSNG FROM SW TO NE AS NXT BATCH OF SHRA MOVS
BACK INTO THE RGN. KEPT POTNL FOR SOME SLEET TO MIX IN WITH THE
RAIN ACRS PORTIONS OF THE CNTRL SRN TIER AND FINGER LAKES...AND
NRN ONEIDA.
FVRBL JET CONFIGURATION TNGT WITH FCST AREA IN RR QUAD OF THE 250
MB JET...COUPLED WITH A 50 KT SRLY 850 JET. GOOD ISEN LIFT TNGT
INTO FRI AHEAD OF THE OCCLUDED FNT. COOLEST AIR WILL RESIDE ACRS
ERN ZONES...BUT MDLS AGAIN MAY BE OVERDONE WITH THE LOW LVL COOL
AIR. RETAINED POTNL FOR SOME SLEET FROM NRN ONEIDA INTO THE WRN
CATSKILLS. COULD GET FAIRLY GUSTY TNGT...SPCLY HIGHER ELEVATIONS...AS
SELY FLOW INCRS.
WE`LL PRBLY SEE A GOOD 3/4 TO ONE INCH OF RAIN THU NGT INTO
FRI. WE SHOULD BE ABLE TO HANDLE THESE AMTS...BUT A FEW MAIN STEM
POINTS MAY APRCH CAUTION STAGE.
LASTLY...CAN`T RULE OUT ISOLD TSRA THIS AFTN OR TNGT...SPCLY ACRS
PA...BUT WILL JUST GO WITH SHRA FOR NOW AND LET LATER UPDATES ADD
MENTION IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
OCCLUDED FNT PASSES ON FRI...WITH BATCH OF RAIN XPCTD TO MOV OUT
OF ERN ZONES FRI AFTN. MAIN UPR TROF REMAINS OVER THE
GTLAKES...AND S/WV`S EMBEDDED IN THE SWLY FLOW ACRS NY/PA COULD
TRIGGER SCT -SHRA...WITH POTNL FOR -SHSN LATER AT NGT. A WEAK WAVE
IS EXPECTED TO PASS FRI NGT...WITH A STRONGER S/WV ON SAT.
RETAINED CHC POPS MAINLY ACRS CNTRL NY AND NRN PA...WITH ONLY SLGT
CHC POPS FAR SE ZONES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US LIFTS EARLY IN
THE LONG TERM. NW FLOW CONTINUES SAT NGT TO SUN SO POSSIBLY
FLURRIES AND SPRINKLES. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR LATE SUNDAY BEFORE A WARM FRONT LIFTS NE WITH RAIN FOR THE
AREA STARTING SUN NGT. ONCE AGAIN THIS FRONT WILL STALL ACROSS THE
AREA UNTIL WED WHEN A COLD FRONT APPROACHES AHEAD OF A LARGE UL
TROF. MODELS MAY BE TOO FAST WITH THE COLD FRONT SO OFF AND ON
SHOWERS MOST LIKELY SCENARIO.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AVIATION FORECAST REMAINS DIFFICULT...DUE TO COMPLICATIONS OF
BATCHES OF SHOWERS MOVING ALONG A WAFFLING FRONTAL BOUNDARY IN OUR
VICINITY. LOW LEVEL DRY AIR COURTESY OF VEERING LIGHT FLOW BETWEEN
WAVES FOUND ITS WAY INTO KSYR-KRME...LIFTING CIGS VFR THERE THIS
MORNING. OTHER TERMINALS IFR TO LOW END MVFR...EVEN LIFR FOR
HILLTOP TERMINALS KBGM AND KITH. WEAK WAVE OF SHOWERS MOVING
THROUGH EARLY THIS MORNING WILL ACTUALLY SERVE TO STIR THE CIG
WHERE IT IS VERY LOW...MAINLY MVFR AS IT MOVES THROUGH.
ADDITIONAL WAVES WILL AFFECT THE REGION FROM MIDDAY THROUGH
EVENING...THE INDIVIDUAL TIMING OF WHICH IS CHALLENGING AND LOW
CONFIDENCE. THE ASSOCIATED NEARLY STATIONARY FRONT WILL THEN
EDGE NORTHWARD WITH TIME...PERHAPS GIVING KAVP-KELM-KBGM-KITH A
RELATIVE BREAK RAIN-WISE THIS EVENING...BUT POSITIONING OF
BOUNDARY WILL CONTINUE TO FAVOR RAIN THIS EVENING FOR KSYR-KRME.
SEVERAL TERMINALS WILL CONTINUE OR RETURN TO IFR CONDITIONS
TONIGHT...ESPECIALLY AS COLD FRONT OF SYSTEM MOVES INTO AREA
TOWARDS 12Z FRIDAY. WINDS THROUGH THE TAF PERIOD WILL BE LIGHT YET
VEERING WITH TIME...GENERALLY FROM A NORTHERLY DIRECTION THIS
MORNING TO AND EASTERLY ONE BY THIS EVENING...EVEN TOWARDS
SOUTHEAST OVERNIGHT TONIGHT. SEE TAFS FOR SPECIFICS.
.OUTLOOK...
FRI...MVFR WITH PDS OF IFR AS SHOWERY FRONT PASSES...ESPECIALLY MORNING.
SAT AND SUN...VFR...PSBL MVFR IN MIXED SHWRS.
SUN NGT AND MON...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM/MDP
NEAR TERM...CMG/DGM
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
627 AM EDT THU APR 11 2013
.SYNOPSIS...
UNSETTLED CONDITIONS WILL PREVAIL INTO SATURDAY AS A COMPLEX AREA OF LOW
PRESSURE MOVES FROM THE GREAT LAKES INTO THE NORTHEAST. SHOWERS...POSSIBLY
MIXED SLEET OVER PORTIONS OF CENTRAL NEW YORK...CAN BE EXPECTED
INTO FRIDAY...WITH SCATTERED RAIN OR SNOW SHOWERS PERSISTING INTO
SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
620 AM UPDATE...
TD`S HAVE FALLEN INTO THE L/M30S ACRS THE FINGER LAKES AND CNTRL
SRN TIER...WITH M20S JUST S OF LAKE ONTARIO. POTNL FOR SOME PL THIS
MRNG AS BAND OF SHRA ENTERS THESE AREAS. SIG DIFFS IN THE PROFILES
FOR NRN ONEIDA W/RESPECT TO A MIX LATER TDA AND TNGT BUT WITH LOW
CONFIDENCE WILL LET DAY SHIFT TAKE A CLOSER LOOK AT THE 12Z DATA.
PREV BLO...
NOT MUCH CHG FROM
PREV FCST. INITIAL LOOK AT MDL GUIDANCE APPEARED TO SHOW A COOL
BIAS AT F06 W/RESPECT TO T/TD`S. GROUND TEMPS WILL BE RELATIVELY
WARM...AND WE DON`T SEE SFC TEMPS OR SFC WET BULBS GETTING BLO 32F
THIS MRNG...REDUCING OR ELIMINATING ANY FZRA THREAT. THIS HAS BEEN
REFLECTED IN THE LATEST WWD GUIDANCE WHICH LOOKS GOOD FROM OUR
PERSPECTIVE. POPS INCRSNG FROM SW TO NE AS NXT BATCH OF SHRA MOVS
BACK INTO THE RGN. KEPT POTNL FOR SOME SLEET TO MIX IN WITH THE
RAIN ACRS PORTIONS OF THE CNTRL SRN TIER AND FINGER LAKES...AND
NRN ONEIDA.
FVRBL JET CONFIGURATION TNGT WITH FCST AREA IN RR QUAD OF THE 250
MB JET...COUPLED WITH A 50 KT SRLY 850 JET. GOOD ISEN LIFT TNGT
INTO FRI AHEAD OF THE OCCLUDED FNT. COOLEST AIR WILL RESIDE ACRS
ERN ZONES...BUT MDLS AGAIN MAY BE OVERDONE WITH THE LOW LVL COOL
AIR. RETAINED POTNL FOR SOME SLEET FROM NRN ONEIDA INTO THE WRN
CATSKILLS. COULD GET FAIRLY GUSTY TNGT...SPCLY HIGHER ELEVATIONS...AS
SELY FLOW INCRS.
WE`LL PRBLY SEE A GOOD 3/4 TO ONE INCH OF RAIN THU NGT INTO
FRI. WE SHOULD BE ABLE TO HANDLE THESE AMTS...BUT A FEW MAIN STEM
POINTS MAY APRCH CAUTION STAGE.
LASTLY...CAN`T RULE OUT ISOLD TSRA THIS AFTN OR TNGT...SPCLY ACRS
PA...BUT WILL JUST GO WITH SHRA FOR NOW AND LET LATER UPDATES ADD
MENTION IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
OCCLUDED FNT PASSES ON FRI...WITH BATCH OF RAIN XPCTD TO MOV OUT
OF ERN ZONES FRI AFTN. MAIN UPR TROF REMAINS OVER THE
GTLAKES...AND S/WV`S EMBEDDED IN THE SWLY FLOW ACRS NY/PA COULD
TRIGGER SCT -SHRA...WITH POTNL FOR -SHSN LATER AT NGT. A WEAK WAVE
IS EXPECTED TO PASS FRI NGT...WITH A STRONGER S/WV ON SAT.
RETAINED CHC POPS MAINLY ACRS CNTRL NY AND NRN PA...WITH ONLY SLGT
CHC POPS FAR SE ZONES.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US LIFTS EARLY IN
THE LONG TERM. NW FLOW CONTINUES SAT NGT TO SUN SO POSSIBLY
FLURRIES AND SPRINKLES. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR LATE SUNDAY BEFORE A WARM FRONT LIFTS NE WITH RAIN FOR THE
AREA STARTING SUN NGT. ONCE AGAIN THIS FRONT WILL STALL ACROSS THE
AREA UNTIL WED WHEN A COLD FRONT APPROACHES AHEAD OF A LARGE UL
TROF. MODELS MAY BE TOO FAST WITH THE COLD FRONT SO OFF AND ON
SHOWERS MOST LIKELY SCENARIO.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
AVIATION FORECAST REMAINS DIFFICULT...DUE TO COMPLICATIONS OF
BATCHES OF SHOWERS MOVING ALONG A WAFFLING FRONTAL BOUNDARY IN OUR
VICINITY. QUIET AT THE MOMENT PRECIPITATION-WISE...BUT NEXT WAVE
OF SHOWERS WILL SKIM THROUGH BEGINNING AROUND 09Z IN
AVP...FOLLOWED BY REMAINDER OF TERMINALS LATER IN THE MORNING. LOW
LEVEL DRY AIR COURTESY OF VEERING LIGHT FLOW BETWEEN WAVES IS
SNEAKING INTO KSYR-KRME...LIFTING CIGS INTO MVFR OR EVEN VFR THERE
THIS MORNING. OTHER TERMINALS EXCEPT KAVP ARE IFR OR LIFR...THOUGH
NOMINAL IMPROVEMENTS MAY OCCUR TOWARDS DAWN AS VEERING FLOW ATTEMPTS
TO BRING DRY LOW LEVEL AIR.
ADDITIONAL WAVES WILL AFFECT THE REGION FROM MIDDAY THROUGH
EVENING...THE INDIVIDUAL TIMING OF WHICH IS CHALLENGING AND LOW
CONFIDENCE. THE ASSOCIATED NEARLY STATIONARY FRONT WILL THEN
ATTEMPT TO EDGE NORTHWARD WITH TIME...PERHAPS GIVING KAVP-KELM-
KBGM-KITH A RELATIVE BREAK RAIN-WISE THIS EVENING BEFORE COLD
FRONT OF THE SYSTEM APPROACHES AFTER 06Z FRIDAY...BUT POSITIONING
OF BOUNDARY WILL CONTINUE TO FAVOR RAIN THIS EVENING FOR KSYR-
KRME. SEVERAL TERMINALS WILL CONTINUE OR RETURN TO IFR CONDITIONS
THIS EVENING. WINDS THROUGH THE TAF PERIOD WILL BE LIGHT YET
VEERING WITH TIME...GENERALLY FROM A NORTHERLY DIRECTION TO AND
EASTERLY ONE...SEE TAFS FOR SPECIFICS.
.OUTLOOK...
LATE THU NIGHT TO FRI...MVFR WITH PDS OF IFR AS SHOWERY FRONT PASSES.
SAT AND SUN...VFR...PSBL MVFR IN MIXED SHWRS.
SUN NGT AND MON...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM/MDP
NEAR TERM...CMG/DGM
SHORT TERM...DGM
LONG TERM...TAC
AVIATION...MDP
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
1033 AM EDT THU APR 11 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL APPROACH THE REGION FROM THE WEST TODAY AND
CROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA TONIGHT. DRY HIGH
PRESSURE WILL BUILD INTO THE AREA FROM THE WEST OVER THE WEEKEND. A
WEAK LOW PRESSURE SYSTEM WILL DEVELOP ALONG THE WESTERN GULF COAST
ON SUNDAY AND BRING MOISTURE BACK ACROSS THE SOUTHEAST THROUGH THE
FIRST HALF OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...REEVALUATING TIMING OF CONVECTION THIS AFTN. 00Z EMC
4KM WRF DOING WELL WITH TIMING OF FRONTAL CONVECTION OVER THE LOWER
TENN AND MISS VALLEYS THIS MRNG. NO DEVELOPMENT YET IN THE WARM
SECTOR EITHER ON RADAR OR ON THE MODEL PROGS FOR THE CURRENT
TIME...BUT IT SHOWS SOME ACTIVITY DEVELOPING IN 16-17Z TIMEFRAME
OVER GA. NONETHELESS THIS WOULD NOT AFFECT ANY OF OUR ZONES UNTIL
AROUND 18Z. LATEST RAP KEEPS ACTIVITY OUT OF THE AREA UNTIL CLOSER
TO 20Z. SOME OTHER HI-RES MODELS DO DEVELOP SOME ISOLATED CONVECTION
PRIOR TO 18Z THOUGH. AS A RESULT I HAVE DELAYED/LOWERED POPS
SLIGHTLY THOUGH CONTINUING TO FOCUS ON THE SAVANNAH RIVER VALLEY FOR
MIDDAY DEVELOPMENT. SEE NO REASON TO THINK THAT SEVERE THREATS ARE
ANY DIFFERENT DESPITE PERHAPS GETTING A LATER START...GIVEN CONTINUED
GUIDANCE AGREEMENT ON ENVIRONMENTAL SHEAR AND DECENT INSTABILITY.
OTHERWISE...ADJUSTED SKY COVER FOR LATEST TRENDS AND SLOWED WARMING
UNTIL LOWER STRATUS MIX OUT LATE MRNG.
AS OF 345 AM...THROUGH THIS AFTERNOON...THE CWA WILL REMAIN BETWEEN
A STRONG COLD FRONT OVER THE MISSISSIPPI RIVER VALLEY AND HIGH
PRESSURE CENTERED OVER THE WESTERN ATLANTIC. THIS PATTERN WILL
PROVIDE ANOTHER DAY OF RETURN FLOW ACROSS THE REGION. MARGINALLY
GUSTY SW WINDS ARE EXPECTED TO DEVELOP AROUND MID DAY AND REMAIN
INTO TONIGHT. RECENT SATELLITE IMAGES INDICATED A SHIELD OF FAIRLY
THICK DEBRIS CIRRUS...MOVING WEST TO EAST. IN ADDITION...A FEW BANDS
OF STRATUS MAY DEVELOP ACROSS PORTIONS OF THE PIEDMONT THIS MORNING.
AS THE H5 RIDGE BUILDS OVER THE WESTERN ATLANTIC...HEIGHTS ACROSS
THE CWA WILL DECREASE. LLVL THICKNESSES AND H85 TEMPERATURES WILL
COOL A CATE OR TWO FROM YESTERDAY. THE COMBINATION OF INCREASING SKY
COVER AND SLIGHTLY COOLER LLVL TEMPS SHOULD RESULT IN HIGH TEMPS
AROUND 5 DEGREES LOWER THAN OBSERVED YESTERDAY...OR 5 DEGREES WARMER
THAN NORMAL. HIGHS IN THE U70S TO NEAR 80 WILL COMBINE WITH SFC
DEWPOINTS IN THE L60S TO SUPPORT A BROAD FIELD OF WEAK INSTABILITY
BY MID AFTERNOON. THE INSTABILITY SHOULD SUPPORT A HEALTHY FIELD OF
CU...HOWEVER...LINGERING WARM TEMPS AROUND H65 SHOULD WEAKLY CAP
DEEP CONVECTION FROM MORNING THROUGH MID AFTERNOON.
CONDITIONS WILL BECOME MORE SUITABLE FOR DEEP CONVECTION ACROSS THE
UPPER SAVANNAH VALLEY AND PORTIONS OF THE UPSTATE DURING THE LATE
AFTERNOON HOURS. MID LEVEL HEIGHTS ARE EXPECTED TO STEADILY DECREASE
AS AN INCREASINGLY NEGATIVELY TILTED TROF PUSH ACROSS THE DEEP
SOUTH. AS THE HEIGHTS DECREASE...THE WEAK AFTERNOON H85 INVERSION
ERODES...EASING CONVECTION TO DEEPEN WITHIN A LAYER OF CAPE AROUND
1000 J/KG. IN ADDITION...THE NEGATIVELY TILTED H5-H7 TROF WILL
RESULT IN THE LLVL WINDS TO BACK. IT IS DURING THIS PERIOD OF BACK
WIND FIELDS...FROM 23Z THROUGH 5Z...THAT NE GA AND SC 0-1KM HELICITY
RANGES FROM 150 TO 250...WITH SHEAR BETWEEN 20 TO 25 M/S. SWEAT
VALUES EXCEED 300 DURING THE MID EVENING HOURS. FORECAST SOUNDINGS
INDICATE THAT SIMILAR KINEMATICS SPREAD ACROSS THE CLT METRO AREA
BETWEEN MIDNIGHT INTO 4 AM. IN FACT...THE NAM HODOGRAPHS OVER CLT
APPEARS MORE TURNED...AS BL WINDS BECOME SE.
IT IS INTERESTING TO EVALUATE THE CONVECTIVE MODE IN THE CONVECTION
ALLOWING HIGH RES MODELS. EACH SOLUTION APPEARS TO SUPPORT TWO
ROUNDS OF SIGNIFICANT CONVECTION. THE FIRST ROUND DEVELOPS WELL
AHEAD OF THE FRONTAL BAND...WITH A CLUSTER FAVORED TO INITIALIZE
ACROSS THE CENTRAL SAVANNAH RIVER VALLEY AFTER 19Z. THIS CONVECTION
APPEARS TO ORGANIZED IN A NW TO SE ORIENTED BOW...SURGING NE ACROSS
THE UPSTATE. THE SECOND ROUND IS CLOSELY ASSOCIATED WITH THE SFC
COLD FRONT. THIS ACTIVITY APPEARS TO STAY INTACT AS IT CROSS THE NE
GA AND THE WESTERN CAROLINAS. GIVEN THE AMOUNT OF
HELICITY...SHEAR...AND CAPES NEAR 1000 J/KG...THE CONVECTIVE MODE
APPEARS LESS LINEAR THAN WHEN THE FRONT WAS FURTHER WEST.
INSTEAD...SIMULATED REFLECTIVITY SUGGESTS THAT CONVECTION WILL
ARRIVE WITH THE SECOND ROUND AS A COMBINATION OF SUPERCELLS AND
SHORT LINE SEGMENTS. WE WILL CONTINUE TO HIGHLIGHT THE THREAT OF
DAMAGING WINDS AND POSSIBLY OF A TORNADO OR TWO IN THE HWO. IN
ADDITION...SEVERE HAIL MAY EXIST WITH THE SUPERCELLS.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 255 AM THURSDAY...THE DEPARTING COLD FRONT AND LIFTING UPPER
SHORTWAVE WILL MOVE QUICKLY EAST AWAY FROM THE FORECAST AREA THROUGH
FRIDAY MORNING...WITH THE CONVECTIVE THREAT RAPIDLY ENDING. DEEP
LAYER DRYING WILL THEN SET UP THROUGH THE DAY IN THE WSW FLOW ALOFT
AROUND THE VORTEX OVER THE GREAT LAKES REGION. LOWER LEVEL W TO NW
WINDS WILL PROVIDE DOWNSLOPING E OF THE MTNS TO DRY OUT THE BL AND
ALLOW MAXES TO WARM A COUPLE OF CATEGORIES ABOVE NORMAL DESPITE THE
FALLING POST FROPA THICKNESSES. DRY HIGH PRES WILL BUILD IN FROM THE
WEST ON SATURDAY...WITH PLENTY OF SUNSHINE AND MAX TEMPS SLIGHTLY
ABOVE NORMAL. ANTICIPATE THAT MINS WILL REMAIN JUST WARM ENOUGH TO
PRECLUDE A FROST MENTION FOR SAT NIGHT...BUT WILL HAVE TO WATCH TEMP
TRENDS ALONG THE INTERSTATE 40 CORRIDOR SINCE RADIATING CONDITIONS
WILL BE GOOD LATE.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 310 AM THU...ANOTHER SRN STREAM WAVE WILL DEVELOP ALONG THE
WRN GULF COAST ON SUNDAY. DPVA ASSOCIATED WITH THIS WAVE...AS WELL
AS UPPER JET DIVERGENCE...SHOULD SHOULD CROSS THE AREA SUNDAY NIGHT.
HOWEVER...LOWER LEVEL MOISTURE AND UPGLIDE WILL LIKELY NOT SET UP
UNTIL DAYBREAK MONDAY AND COULD LINGER THROUGH MON NIGHT.
A FLAT UPPER RIDGE WILL BUILD IN BEHIND THE DEPARTING SHORTWAVE ON
MONDAY...WITH RIDGING REMAINING DOMINANT OVER THE SE THROUGH MID
WEEK AS TEMPERATURE REBOUND. HOWEVER...LOW LEVEL MOISTURE AND SRLY
FLOW WILL ALSO PERSIST UNDER THE RIDGE TO CREATE MORE CLOUDS THAN
NOT THROUGH THE PERIOD. ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE EACH DAY...ESPECIALLY OVER THE MTNS
AND DURING THE DIURNALLY FAVORED AFTN/EVENING HOURS.
&&
.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT /15Z UPDATE/...MVFR STRATUS EXPECTED TO PERSIST THROUGH THE
MORNING AS THERE HAS BEEN LITTLE IMPROVEMENT NEAR THE FIELD. WARMING
AND ATTENDANT MIXING HAS BEEN SLOW AND IT APPEARS THIS WILL BE
REQUIRED TO ERODE THE STRATUS. INSTABILITY SHOULD BE SUFFICIENT TO
ALLOW SOME LOW VFR CU TO QUICKLY FILL IN BEHIND IT...ESPECIALLY IN
LIGHT OF CU DEVELOPING OVER FAR NW SC.
CURRENTLY EXPECTING SIMILAR TIMING AND PLACEMENT OF SHRA/TSRA
ASSOCIATED WITH A STRONG COLD FRONT TO THOUGHTS AT 12Z ISSUANCE.
CONVECTION ALLOWING MODELS INDICATE THAN PRE FRONTAL SHRA/TSRA WILL
DEVELOP OVER THE CENTRAL SAVANNAH RIVER VALLEY BETWEEN
19-21Z...TRACKING NE...REACHING CLT BETWEEN 22-00Z. WILL MENTION A
TEMPO BETWEEN 22-24Z...WITH PREDOMINATE TSRA STARTING AT 00Z. MVFR
CEILING SHOULD DEVELOP IN THE WAKE OF THE TSRA...REMAINING THROUGH
12Z. HOWEVER 12Z NAM AND LATEST RAP HAVE SLIGHTLY DELAYED THE ACTION
THIS AFTERNOON SO IF ANYTHING ONSET MAY BE AN HOUR LATER.
ELSEWHERE...WILL KEEP MVFR CEILING WITH SCT IFR THROUGH MID MORNING
UNTIL MIXING ERODES STRATUS. SSW WIND WILL BECOME GUSTY BY MID DAY
AND REMAIN THROUGH EARLY FRIDAY MORNING.
THE NEXT ISSUE WILL BE THE TIMING AND PLACEMENT OF SHRA/TSRA
ASSOCIATED WITH A STRONG COLD FRONT. CONVECTION ALLOWING MODELS
INDICATE THAN PRE FRONTAL SHRA/TSRA WILL DEVELOP OVER THE CENTRAL
SAVANNAH RIVER VALLEY BETWEEN 19-21Z...TRACKING NE...REACHING THE
PIEDMONT TAFS AROUND BETWEEN 20-24Z. I WILL MENTION A PROB30...WITH
PREDOMINATE TSRA STARTING AT 1Z. MVFR CEILINGS MAY SPREAD ACROSS
THE REGION IN THE WAKE OF THE FIRST ROUND OF CONVECTION. FROPA WILL
OCCUR AFTER 6Z.
OUTLOOK...DRY HIGH PRESSURE WILL BUILD BACK OVER THE REGION ON
FRIDAY AND REMAIN THROUGH THE WEEKEND.
CONFIDENCE TABLE...
14-20Z 20-02Z 02-08Z 08-14Z
KCLT HIGH 97% HIGH 88% MED 72% HIGH 100%
KGSP HIGH 91% HIGH 94% HIGH 82% HIGH 100%
KAVL HIGH 100% HIGH 95% HIGH 98% HIGH 93%
KHKY HIGH 89% HIGH 83% MED 61% HIGH 100%
KGMU HIGH 90% HIGH 86% MED 77% HIGH 93%
KAND HIGH 95% HIGH 90% HIGH 93% HIGH 98%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...HG
NEAR TERM...NED/WIMBERLEY
SHORT TERM...HG
LONG TERM...HG
AVIATION...NED/WIMBERLEY
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
623 AM CDT THU APR 11 2013
.UPDATE...
MADE SOME ADJUSTMENTS TO THE WINTER WEATHER HEADLINES. DROPPED
LYMAN...HAND AND BUFFALO COUNTIES FROM THE WARNING AS SNOW LOOKS
TO JUST BE LIGHT THERE THROUGH THE REST OF THE MORNING. ADDED
BROWN AND MARSHALL COUNTIES TO THE WINTER STORM WARNING WITH
SEVERAL INCHES ALREADY FALLING OVERNIGHT AND MORE COMING THIS
MORNING. WILL LIKELY SEE TOTAL AMOUNTS IN EXCESS OF 6 INCHES IN
THOSE TWO COUNTIES.
SEE UPDATED AVIATION DISCUSSION BELOW.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
LEFT EXIT REGION RESPONSIBLE FOR TRANSIENT BANDS OF MODERATE TO
HEAVY SNOWFALL THIS MORNING. HRRR DEPICTING CURRENT CONDITIONS
FAIRLY WELL...AND TRANSITIONS AREA OF HIGHEST RETURNS/BEST FORCING
NORTH OF THE CWA BY MID DAY. ASIDE FROM MINOR CONFIGURATION
CHANGES TO HEADLINES EARLIER...WILL STICK WITH CURRENT TIMING ON
END OF ACCUMULATING SNOWFALL. SREF PROBABILITIES STILL SUGGESTING
A FEW SPOTS TO TOP 8 INCHES IN FAR EASTERN SOUTH DAKOTA/MINNESOTA
COUNTIES.
WITH THE LAST OF THE SYNOPTIC SCALE SNOWFALL MOVING OUT...MODELS
STILL HINT AT A PERSISTENT STRATUS LAYER OVER THE REGION THROUGH
THE START OF THE WEEKEND. THE LACK OF THERMAL ADVECTION...AND H85
READINGS AROUND -7C OR A STANDARD DEVIATION BELOW CLIMO...SUGGEST
FORECAST TEMPERATURES THROUGH SATURDAY WILL REMAIN WELL BELOW
NORMAL. WE WILL SEE SOME DECENT THERMAL ADVECTION BETWEEN 1 TO 3KFT
LATE IN THE PERIOD OUT WEST...HOWEVER SOUTHEASTERLY LOW LEVEL FLOW
WILL CUT DOWN ON MIXING POTENTIAL AND INCREASING MID/HIGH CLOUDS
SHOULD LIMIT DAYTIME HEATING. THUS...HIGHS STILL SOME 10-15
DEGREES BELOW NORMAL THE HIGH POINT IN TEMPERATURES THIS PERIOD.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
A LOW PRESSURE SYSTEM WILL BE APPROACHING THE AREA FROM THE WEST
WHEN THE PERIOD STARTS. WAA PRECIPITATION ON THE LEADING EDGE OF
THE SYSTEM LOOKS PRETTY CERTAIN SATURDAY NIGHT...ESPECIALLY ACROSS
THE EASTERN CWA. THE SYSTEM SWINGS TO THE NORTHEAST ON SUNDAY AND
THERE LOOKS TO BE A BREAK IN THE PRECIPITATION SUNDAY NIGHT AND
MONDAY. ANOTHER SYSTEM THEN TRACKS ACROSS THE CENTRAL OR SOUTHERN
PLAINS DURING THE LATTER HALF OF THE PERIOD. THE GFS AND THE GEM
ARE CONSIDERABLY FURTHER SOUTH WITH THIS SYSTEM THAN THE
ECMWF...SO THERE IS A POSSIBILITY THAT WE WILL REMAIN DRY.
HOWEVER...AM NOT COMFORTABLE STRAYING THAT FAR FROM THE
ALLBLEND...SO WILL LEAVE A SMALL POP IN MONDAY NIGHT THROUGH
WEDNESDAY TO ACCOUNT FOR TRACKING DIFFERENCES.
WITH NEW SNOW COVER OVER MUCH OF THE CWA...DO NOT EXPECT TO SEE
TEMPERATURES REACH MEX GUIDANCE VALUES...AND WILL STAY ABOUT 5 TO
10 DEGREES BELOW IT FOR DAYTIME HIGHS. THIS WILL RESULT IN HIGH
TEMPERATURES MAINLY IN THE 30S AND 40S...WITH OVERNIGHT LOWS IN
THE 20S.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
THE TAF FOR KATY REMAINS NIL DUE TO THE ASOS EQUIPMENT BEING NON
FUNCTIONAL.
AN AREA OF SNOW WILL REMAIN OVER THE EASTERN CWA DURING THE
MORNING HOURS. MVFR CIGS AND VSBYS WILL OCCASIONALLY BECOME IFR
UNDER THE HEAVIER SNOW BANDS. THE SNOW WILL TAPER OFF AND COME TO
AN END BY THIS EVENING...BUT CIGS WILL BECOME IFR AND REMAIN THAT
WAY THROUGH THE OVERNIGHT HOURS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR BROWN-CLARK-
CODINGTON-DAY-DEUEL-GRANT-HAMLIN-MARSHALL-ROBERTS-SPINK.
WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
EDMUNDS-FAULK-MCPHERSON.
MN...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR BIG STONE-
TRAVERSE.
&&
$$
UPDATE...PARKIN
SHORT TERM...CONNELLY
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS ABERDEEN SD
400 AM CDT THU APR 11 2013
.SHORT TERM...THROUGH SATURDAY
LEFT EXIT REGION RESPONSIBLE FOR TRANSIENT BANDS OF MODERATE TO
HEAVY SNOWFALL THIS MORNING. HRRR DEPICTING CURRENT CONDITIONS
FAIRLY WELL...AND TRANSITIONS AREA OF HIGHEST RETURNS/BEST FORCING
NORTH OF THE CWA BY MID DAY. ASIDE FROM MINOR CONFIGURATION
CHANGES TO HEADLINES EARLIER...WILL STICK WITH CURRENT TIMING ON
END OF ACCUMULATING SNOWFALL. SREF PROBABILITIES STILL SUGGESTING
A FEW SPOTS TO TOP 8 INCHES IN FAR EASTERN SOUTH DAKOTA/MINNESOTA
COUNTIES.
WITH THE LAST OF THE SYNOPTIC SCALE SNOWFALL MOVING OUT...MODELS
STILL HINT AT A PERSISTENT STRATUS LAYER OVER THE REGION THROUGH
THE START OF THE WEEKEND. THE LACK OF THERMAL ADVECTION...AND H85
READINGS AROUND -7C OR A STANDARD DEVIATION BELOW CLIMO...SUGGEST
FORECAST TEMPERATURES THROUGH SATURDAY WILL REMAIN WELL BELOW
NORMAL. WE WILL SEE SOME DECENT THERMAL ADVECTION BETWEEN 1 TO 3KFT
LATE IN THE PERIOD OUT WEST...HOWEVER SOUTHEASTERLY LOW LEVEL FLOW
WILL CUT DOWN ON MIXING POTENTIAL AND INCREASING MID/HIGH CLOUDS
SHOULD LIMIT DAYTIME HEATING. THUS...HIGHS STILL SOME 10-15
DEGREES BELOW NORMAL THE HIGH POINT IN TEMPERATURES THIS PERIOD.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
A LOW PRESSURE SYSTEM WILL BE APPROACHING THE AREA FROM THE WEST
WHEN THE PERIOD STARTS. WAA PRECIPITATION ON THE LEADING EDGE OF
THE SYSTEM LOOKS PRETTY CERTAIN SATURDAY NIGHT...ESPECIALLY ACROSS
THE EASTERN CWA. THE SYSTEM SWINGS TO THE NORTHEAST ON SUNDAY AND
THERE LOOKS TO BE A BREAK IN THE PRECIPITATION SUNDAY NIGHT AND
MONDAY. ANOTHER SYSTEM THEN TRACKS ACROSS THE CENTRAL OR SOUTHERN
PLAINS DURING THE LATTER HALF OF THE PERIOD. THE GFS AND THE GEM
ARE CONSIDERABLY FURTHER SOUTH WITH THIS SYSTEM THAN THE
ECMWF...SO THERE IS A POSSIBILITY THAT WE WILL REMAIN DRY.
HOWEVER...AM NOT COMFORTABLE STRAYING THAT FAR FROM THE
ALLBLEND...SO WILL LEAVE A SMALL POP IN MONDAY NIGHT THROUGH
WEDNESDAY TO ACCOUNT FOR TRACKING DIFFERENCES.
WITH NEW SNOW COVER OVER MUCH OF THE CWA...DO NOT EXPECT TO SEE
TEMPERATURES REACH MEX GUIDANCE VALUES...AND WILL STAY ABOUT 5 TO
10 DEGREES BELOW IT FOR DAYTIME HIGHS. THIS WILL RESULT IN HIGH
TEMPERATURES MAINLY IN THE 30S AND 40S...WITH OVERNIGHT LOWS IN
THE 20S.
&&
.AVIATION...
06Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
A BAND OF SNOW WILL CONTINUE TO MOVE NORTH/NORTHWEST INTO THE
REGION THROUGH THE NIGHT. LOWEST IFR VSBYS ARE EXPECTED AT
KATY/KABR OVERNIGHT WITH IMPROVEMENT THURSDAY MORNING. KPIR/KMBG
WILL ALSO SEE LOWERED VSBYS DUE TO SNOWFALL...MOSTLY IN THE MVFR
RANGE OVERNIGHT. CIGS WILL VARY WIDELY FROM IFR TO VFR DEPENDING
UPON THE INTENSITY OF SNOWFALL.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR CLARK-
CODINGTON-DAY-DEUEL-GRANT-HAMLIN-ROBERTS-SPINK.
WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
EDMUNDS-FAULK-MCPHERSON.
WINTER STORM WARNING UNTIL 7 AM CDT THIS MORNING FOR BUFFALO-
HAND-LYMAN.
WINTER WEATHER ADVISORY UNTIL 7 PM CDT THIS EVENING FOR BROWN-
MARSHALL.
MN...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR BIG STONE-
TRAVERSE.
&&
$$
SHORT TERM...CONNELLY
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION
NWS DENVER/BOULDER CO
1045 AM MDT THU APR 11 2013
.UPDATE...
&&
.SHORT TERM...SNOW CONTINUING ACROSS MOUNTAINS WITH THE BEST
SNOWFALL ALONG CONTINENTAL DIVIDE OF SUMMIT AND GRAND COUNTIES.
NORTHWEST FLOW PROVIDING GOOD OROGRAPHICS AS AREA HAS BEEN IN THE
FAVORED LIFT OF JET PASSING ACROSS WYOMING. ALSO...LAPSE RATES
AROUND 6 OR 7 C/KM ADDING TO SNOWFALL. SOME LIGHT SNOW OCCURRING
ACROSS MOUNTAIN VALLEYS. ACROSS FOOTHILLS AND PLAINS...A FEW
SHOWERS TRYING TO DEVELOP NEAR THE WYOMING BORDER BUT DOWNSLOPE
FLOW LIMITING THE DEVELOPMENT. FAVORED OROGRAPHICS IN NORTHWEST
FLOW ALOFT TO CONTINUE ACROSS MOUNTAINS THROUGH THE DAY...THOUGH
FAVORED LIFT FROM THE JET WILL BE SHIFTING INTO NEBRASKA BY THE
AFTERNOON. PLATTEVILLE PROFILER SHOWING WINDS ALOFT HAVE DECREASED
A BIT...IMPLYING THE JET IS MOVING AWAY FROM THE AREA.
STILL...LATEST RAP SHOWS LAPSE RATES AROUND 6 C/KM CONTINUING
THROUGH THE DAY...AND WITH OROGRAPHICS AND MOISTURE PRESENT...
SHOULD SEE SNOW CONTINUING OVER THE MOUNTAINS THROUGH THE DAY.
ADDITIONAL ACCUMULATIONS LOOK TO BE AROUND 3 TO 5 INCHES ALONG THE
DIVIDE...WITH LESS AMOUNTS ELSEWHERE. WILL CONTINUE THE MOUNTAIN
ADVISORY. ELSEWHERE...STILL APPEARS PRECIPITATION CHANCES LOOK LOW
GIVEN LACK OF ANY MID LEVEL QG ASCENT AND LOCAL DOWNSLOPE. BUT
WITH JET IN THE AREA...WILL CONTINUE THE CURRENT POPS. TEMPS THIS
AFTERNOON LOOK A BIT WARM FOR SNOW ON THE PLAINS...COULD BE SOME
MIX DURING THE EVENING. PRECIP TO DECREASE ACROSS MOUNTAINS AND
END ACROSS PLAINS DURING THE EVENING AS DRIER SUBSIDENT AIR MOVES
INTO THE AREA. SOME CLEARING ACROSS PLAINS COULD LEAD TO FOG
DEVELOPMENT AFTER MIDNIGHT.
.AVIATION...CURRENT TAF TRENDS LOOK ON TRACK...THOUGH WINDS HAVE
SHIFTING TO THE NORTHWEST. SHOULD SHIFT TO THE NORTH NORTHEAST
AFTER 18Z. STILL SOME FOG FLOATING AROUND AREA AIRPORTS...SHOULD
BE DISSIPATING BY 18Z. OTHERWISE...CEILINGS OF AROUND 7000 FEET
AGL TO PREVAIL THROUGH THE AFTERNOON. A FEW SHOWERS POSSIBLE THIS
AFTERNOON AND EVENING MAINLY EAST AND SOUTH OF DENVER. COULD SEE
CEILINGS LOWER TO AROUND 5000-6000 FEET WITH THE PASSING SHOWERS.
IF SHOWERS AFFECT THE AIRPORTS...COULD BE A MIXTURE OF RAIN AND
SNOW AROUND 23Z...WITH MAINLY SNOW AROUND 02Z. THE SHOWERS SHOULD
BE BRIEF WITH NO ACCUMULATION EXPECTED. SOME CLEARING BY MIDNIGHT
WITH A SLIGHT CHANCE OF FOG DEVELOPING. WILL CONTINUE WITH THE
VCFG FOR NOW.
&&
.PREV DISCUSSION... /ISSUED 412 AM MDT THU APR 11 2013/
SHORT TERM...A POTENT LITTLE DISTURBANCE BEING CARRIED ALONG BY
80+KT NORTHWESTERLY FLOW ALOFT IS ALREADY BRINGING SNOW AND GUSTY
WINDS TO THE NORTHERN MTNS OF COLORADO. IN THE PAST HOUR OR SO...
CDOT CAMS AT THE EISENHOWER TUNNEL AND ON VAIL PASS HAVE SHOWN
SOME PRETTY WINTERY CONDITIONS UP THERE...AND THE BEST MOISTURE
AND FORCING FOR ASCENT STILL UPSTREAM OVER NERN UT/SWRN WY.
THEREFORE SHOULD CONTINUE TO SEE A GRADUAL DETERIATION IN WX
CONDITIONS AT HIGHER ELEVATIONS IN MTN ZONES 31..33 AND 34 DURING
THE NEXT 2-4 HOURS. COULD SEE SNOWFALL RATES APPROACHING 1 TO 1.5
INCHES PER HOUR LATER THIS MORNING ON WEST-NORTHWEST FACING
SLOPES...WITH TOTAL SNOW ACCUMULATIONS BY 00Z TODAY IN THE 4 TO 7
INCH RANGE. HOWEVER...MAY SEE HIGHER AMOUNTS IN PARTS OF THE PARK
AND GORE RANGES. FOR THAT REASON...HAVE ISSUED A WINTER WEATHER
ADVISORY FOR SNOW AND BLOWING SNOW IN THE ABOVE MENTION MTN ZONES
NOW UNTIL 6 PM MDT TODAY. BASED ON ITS CURRENT FORWARD SPEED AND
MODEL GUIDANCE...SHOULD SEE HIGH COUNTRY SNOWFALL AND WIND SPEEDS
DIMINISHING THIS EVENING WITH DRYING AND SUBSIDENCE MOVING IN
BEHIND THIS SYSTEM.
ELSEWHERE...SHOULD SEE A STEADY INCREASE IN CLOUD COVER OVER THE
PLAINS THIS MORNING WITH MOSTLY TO OVERCAST SKIES BY MIDDAY...IF
NOT SOONER THAN THAT. THE LACK OF ANY SIGNIFICANT FORCING FOR
ASCENT WITH THE PASSING DISTURBANCE EAST OF THE MTNS SUGGESTS
PRECIPITATION WILL BE LIMITED IN COVERAGE. AFTERNOON AND EARLY
EVENING APPEARS TO BE THE BEST TIME FOR ANY PRECIP ON THE PLAINS.
HAVE INTRODUCED A SCATTERING OF LOW POPS TO REFLECT THIS
POSSIBILITY. FURTHERMORE...MODEL TEMPERATURE GUIDANCE LOOKS TOO
WARM TODAY CONSIDERING THE ANTICIPATED CLOUD COVER AND LINGERING
SNOW COVER. THEREFORE HAVE BACKED OFF ON MAX TEMPS OFFERED BY MOS
GUIDANCE BY AS MUCH 5-10DEGS F.
FOR TONIGHT...SHOULD SEE SKIES GRADUALLY CLEARING FORM NORTHWEST
TO SOUTHEAST BEHIND THIS DISTURBANCE. BUT CLEARING SKIES WILL
ALLOW STRONG RADIATIONAL COOLING TO GENERATE PATCHY FOG ON THE
PLAINS AFTER MIDNIGHT...SOME OF WHICH COULD BE RATHER THICK EAST
OF THE I-25 URBAN CORRIDOR. SHOULD SEE WARMER LOW TEMPERATURES
TONIGHT WITH THE START OF WARMING ALOFT.
LONG TERM...COLORADO WILL BE UNDER A NORTHWEST FLOW PATTERN ON
FRIDAY AND EARLY SATURDAY AS A WEAK DISTURBANCE AND FRONT SLIDES
ACROSS THE AREA FRIDAY AFTERNOON AND EARLY EVENING. APPEARS THE
BEST CHANCE FOR SHOWERS WILL BE OVER THE MOUNTAINS WITH SOME
OROGRAPHIC FLOW AND OVER THE FAR NORTHEAST PLAINS...CLOSER TO THE
DYNAMICAL FORCING AND JET STREAK. SATURDAY LOOKS TO BE THE DRIEST
AND WARMEST DAY OF THE UPCOMING WEEK AS THE FLOW TRANSITIONS AND
INCREASES FROM THE WEST. WITH THE STRONGER WESTERLY FLOW...MAY BE
A BRIEF PERIOD OF HIGH WIND POTENTIAL OVER THE FRONT RANGE ON
SATURDAY NIGHT AS STRONG JET ALOFT MOVES OVER NORTHERN COLORADO.
CROSS SECTIONS SHOW CROSS BARRIER FLOW SHOWING 50-60KT SO
CERTAINLY SOME POTENTIAL THERE FOR HIGH WINDS AND DEPEND ON EXACT
POSITION OF JET.
FOR MONDAY THROUGH WEDNESDAY...LOOKS LIKE ANOTHER UNSETTLED PERIOD
OVER COLORADO AS UPPER LEVEL TROF DEVELOPS OVER THE GREAT BASIN
AND GRADUALLY MOVES ACROSS COLORADO AROUND MID WEEK. MODEL
DIFFERENCES SHOWING UP IN THE TIMING WITH THIS TROF PASSAGE WITH
GFS THE FASTEST AND EUROPEAN THE SLOWEST. NOT A LOT OF CONFIDENCE
EITHER WAY BUT CERTAINLY COOLER TEMPERATURES AND A BETTER CHANCE
FOR SHOWERS MOVING BACK INTO THE REGION BY EARLY NEXT WEEK. BEST
CHANCES TO BE OVER FAR NORTHERN COLORADO...CLOSEST TO THE JET.
AVIATION...LIGHT EASTERLY/UPSLOPE FLOW IN THE LOW LEVELS AND THE
APPROACH FROM THE WEST OF MOISTURE ATTACHED TO AN UPPER LEVEL
WEATHER DISTURBANCE SHOULD KEEP SKIES OVER DENVER AREA AIRPORTS
MOSTLY CLOUD TO OVERCAST ALL DAY. CEILINGS WILL GENERALLY RANGE
FROM 7000 TO 11000 FEET AGL...WITH PERIODS OF LOWER CIGS IN THE
4000-5000 FOOT RANGE. THE LOWERING CEILINGS MAY BE ACCOMPANIED BY
RAIN SPRINKLES OR A BRIEF RAIN SHOWER TODAY...AND POSSIBLY A BRIEF
RAIN AND SNOW SHOWER EARLY THIS EVENING. NOT EXPECTING ANY SNOW
ACCUMULATION WITH THE PASSING SHOWERS. FOR WINDS...LIGHT AND
VARIABLE WINDS EARLY THIS MORNING ARE FORECAST TO BECOME SOUTHEAST
5-8KTS LATER THIS MORNING...THEN EAST-NORTHEAST AT 6-10KTS AFTER
19Z TODAY. BY EARLY THIS EVENING...LOOK FOR A SHIFT TO
NORTHWESTERLY WINDS UNDER 8 KTS...AND EVENTUALLY TO A LIGHT
DRAINAGE WIND PATTERN BY 06Z TONIGHT. THERE IS A SMALL CHANCE THAT
DIA AND BJC COULD SEE PATCHY FOG FORMING AFTER 09Z TONIGHT.
VISIBILITIES IN THE FOG COULD BRIEFLY LOWER TO AROUND 2 MILES.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR COZ031-
033-034.
&&
$$
SHORT TERM...D-L
LONG TERM....ENTREKIN
AVIATION...D-L
AREA FORECAST DISCUSSION
NWS MIAMI FL
139 PM EDT THU APR 11 2013
.AVIATION...
A SCT/BKN CLOUD DECK AT 20KFT WILL CONTINUE ACROSS THE TERMINALS...
WITH A FEW SHOWERS EMBEDDED. THESE SHOWERS WILL REMAIN CLOSE TO ONLY
KAPF...FOR THAT REASON KEPT THE VCSH AS PREVAILING FOR THAT SITE.
SOUTHEASTERLY FLOW WILL CONTINUE GUSTING UP TO 25 KTS AT ALL
TERMINALS THROUGH THE EVENING. WINDS WILL DECREASE IN SPEED
OVERNIGHT...AND WILL ONCE AGAIN PICK UP SPEED BY 12/15Z.
&&
.PREV DISCUSSION... /ISSUED 1002 AM EDT THU APR 11 2013/
UPDATE...
THE LATEST RUC 400 MB ANALYSIS OVERLAID ONTO THE LATEST WATER
VAPOR LOOP SHOWED A RIDGE AXIS EXTENDING NORTH AND NORTHEAST FROM THE
EASTERN GULF OF MEXICO TO NORTHERN FLORIDA AND GENERALLY INDICATES
THIS RIDGE BUILDING EASTWARD OVER THE LOCAL AREA THROUGH THE
COURSE OF THE DAY TODAY. MODEL SOUNDINGS REFLECT THIS AND INDICATE
A DECENT SUBSIDENCE INVERSION JUST ABOVE 500 MB FROM TBW TO MIA.
DESPITE THE STEEP LAPSE RATES NOTED IN THE SOUNDINGS FROM
600-500MB...THIS COULD BE A LIMITING FACTOR FOR DEEP CONVECTION
AND THE OVERALL THUNDERSTORM POTENTIAL THIS AFTERNOON/EARLY
EVENING. HOWEVER...IF THIS IS ERODED...A FEW STRONG STORMS WILL
BECOME A POSSIBILITY LATER TODAY. THESE LAPSE RATES COMBINED WITH
THE MID-LEVEL DRY AIR COULD RESULT IN STRONG WINDS AND SMALL HAIL
AS THE MAIN IMPACTS FROM ANY STRONG STORM THAT DOES DEVELOP.
CONSIDERING THE MEAN LOW-LEVEL FLOW IS SSE UP TO 700MB...THE BEST
CHANCE FOR THESE STORMS WILL REMAIN OVER THE NORTHERN SECTIONS OF
THE LOCAL AREA...ESPECIALLY FROM NAPLES TO THE LAKE REGION.
OUTSIDE OF A FEW MINOR TWEAKS WITHIN THE GRIDDED FORECAST BASED ON
THE MORNING OBSERVATIONS AROUND THE LOCAL AREA...NO MAJOR CHANGES
ARE ANTICIPATED. 85/AG
PREV DISCUSSION... /ISSUED 727 AM EDT THU APR 11 2013/
AVIATION...
VFR CONDITIONS THROUGH THE PERIOD AT ALL TERMINALS. HIGH PRESSURE
OVER THE WESTERN ATLANTIC WATERS WILL KEEP AN EASTERLY FLOW ACROSS
SOUTH FLORIDA TODAY...GUSTING UP TO 20 KTS AT TIMES. A FEW SHOWERS
COULD DEVELOP AND MOVE NEAR THE TERMINALS...BUT COVERAGE AND
LENGTH WILL BE NOT SIGNIFICANT THEREFORE...NO NEED TO MENTION ON
TAFS AT THIS TIME. WILL AMEND IF NECESSARY. WINDS EXPECTED TO
DECREASE IN SPEED AT AROUND 12/02Z.
PREV DISCUSSION... /ISSUED 346 AM EDT THU APR 11 2013/
SHORT TERM...
WITH HIGH PRESSURE TO THE EAST OF SOUTH FLORIDA, A SOUTHEASTERLY
FLOW HAS BROUGHT PLENTY OF MOISTURE TO INITIATE SOME AFTERNOON
THUNDERSTORMS ONCE AGAIN TODAY. THESE STORMS WILL MAINLY BE IN THE
LAKE REGION ONCE AGAIN. IN TERMS OF DYNAMICS, THERE WILL BE 500MB
VORTICITY ADVECTION MOVING ACROSS THE AREA. MODELS INDICATE
BETWEEN 600 AND 1000 JOULES OF CAPE. TYPICAL NEGATIVE LIS, AND
STRONG 500MB OMEGA VALUES. THE 700 MB OMEGAS ARE LESS THAN
YESTERDAY. THE 500MB RIDGE IS BREAKING DOWN, AND THERE WILL BE A
WEAK SHORT WAVE. JET SUPPORT TODAY WILL BE NEGLIGIBLE. SO, HAVE
KEPT CHC POPS OVER THE NORTHWEST AREA, DOWN TO ABOUT I75. IT DOES
LOOK TO BE SOMEWHAT MORE COVERAGE TODAY. ALSO, WHILE THERE WILL BE
SOMEWHAT OF A SEA BREEZE, IT MAY BE HARD TO DETECT AT THE SFC AS
WINDS WILL BE BREEZY TODAY.
TOMORROW WILL SEE A SIMILAR SETUP, EXCEPT TRANSLATED EASTWARD.
ALSO, WINDS TOMORROW WILL TURN MORE SOUTHERLY AND PERHAPS EVEN
MORE SOUTHWESTERLY.
HIGH TEMPERATURES FOR THE NEXT COUPLE OF DAYS WILL CONTINUE TO BE
IN THE MID TO UPPER 80S, TO AROUND 90. LOW TEMPERATURES WILL BE
FAIRLY WARM, WITH LOWS IN THE MID TO UPPER 60S IN THE INTERIOR AND
LOW TO MID 70S ALONG THE COASTAL AREAS.
CONDITIONS WILL BECOME MORE INTERESTING BY SATURDAY MORNING. A LOW
PRESSURE SYSTEM OVER THE PLAINS WILL MOVE EASTWARDS FOR THIS
WEEKEND. THIS SYSTEM WILL BRING A COLD FRONT TO THE FLORIDA
PENINSULA. THE FRONT IS CURRENTLY PROGGED TO STALL JUST NORTH OF
LAKE OKEECHOBEE. THIS WILL KEEP SOUTH FLORIDA IN THE WARM SECTOR
ON SATURDAY. THE MAIN ENERGY ASSOCIATED WITH THE FRONT WILL BE
WELL TO THE NORTH. THERE WILL NOT BE MUCH IN THE WAY OF ANYTHING
FOR SOUTH FLORIDA, EXCEPT INCREASING THE CHANCE FOR THUNDERSTORMS
SATURDAY AFTERNOON. THE AREA OF HIGHER POPS WILL GENERALLY BE
NORTH OF I75, AND HIGHER AS YOU GO NORTH, GETTING CLOSER TO THE
FRONTAL BOUNDARY. IT IS STILL FAR ENOUGH OUT THAT THE CHANCES WILL
CHANGE FOR ANY GIVEN AREA, UP OR DOWN, DEPENDING ON HOW FAR SOUTH
THE FRONT CAN GET. FOR NOW, DID NOT GO ABOVE 50 POPS FOR SATURDAY
AFTERNOON.
LONG TERM...
THE STALLED FRONT WILL SIT AROUND FOR A COUPLE OF DAYS AFTER,
MAKING LITTLE PROGRESS AND SHOULD EVENTUALLY WASH OUT, PROBABLY
FOR THE BEGINNING OF THE WEEK. AS IT DOES WASH OUT, HIGH PRESSURE
WILL AGAIN BRING A SOUTH TO SOUTHEASTERLY FLOW TO SOUTH FLORIDA,
ALLOWING FOR A CHANCE OF A FEW AFTERNOON THUNDERSTORMS TO POPS UP.
MODELS ARE INDICATING A SHORT WAVE MOVING ACROSS NORTH AND
CENTRAL FLORIDA SUNDAY NIGHT, BUT CURRENTLY THINKING IT WILL NOT
AFFECT THE CWA. SO, ONCE THE FRONT WASHES OUT, NOT EXPECTING ANY
REAL PATTERN CHANGE FOR THE REMAINDER OF THE FORECAST PERIOD. HIGH
TEMPERATURES WILL CONTINUE TO RANGE FROM THE LOW TO MID 80S ALONG
THE COAST TO MID TO UPPER 80S, POSSIBLY EVEN LOW 90S IN THE
INTERIOR OF THE STATE.
MARINE...
HIGH PRESSURE WILL REMAIN TO THE EAST OF THE AREA. THIS WILL BRING
CONTINUOUS STIFF SOUTHEAST WINDS OF 15 TO 20KTS TODAY. THEY WILL
BEGIN TO TURN MORE SOUTHERLY TOMORROW, BUT WILL CONTINUE TO BE
FAIRLY STIFF, ALTHOUGH SLIGHTLY LOWER TOMORROW. THERE IS A SLIGHT
CHANCE OF A SHOWER THROUGH TONIGHT AND POSSIBLE A SHOWER OR A
THUNDERSTORM TOMORROW. A WEAK COLD FRONT WILL STALL OVER THE AREA
SATURDAY, BRINGING AN INCREASED CHANCE OF A SHOWER AND/OR A
THUNDERSTORM FOR SATURDAY AFTERNOON.
FIRE WEATHER...
FIRE WEATHER CONCERNS ARE AT A LOW RIGHT NOW AS THERE IS PLENTY OF
SURFACE MOISTURE AROUND. IT WILL BE BREEZY TODAY, WITH WINDS OUT
OF THE SOUTHEAST. THERE IS A CHANCE OF A THUNDERSTORM IN THE
INTERIOR AREAS, ESPECIALLY NORTH, TOWARDS LAKE OKEECHOBEE. THIS
WILL REPEAT AGAIN TOMORROW, EXCEPT WINDS WILL BE MORE SOUTHERLY.
THEN, FOR THE WEEKEND, A COLD FRONT WILL APPROACH SOUTH FLORIDA,
BUT IS NOT EXPECTED TO MAKE IT INTO THE AREA. MODELS ARE SHOWING
IT TO STALL OVER CENTRAL FLORIDA. BUT, IT WILL INCREASE THE CHANCE
FOR THUNDERSTORMS ON SATURDAY AFTERNOON, AND MAYBE ON SUNDAY
AFTERNOON, BEFORE WASHING OUT. WITH WINDS JUST ABOVE THE SURFACE
OF AROUND 15 TO 20 MPH, NOT EXPECTING FOG FORMATION TONIGHT.
HOWEVER, WINDS ARE LOOKING AS THEY MAY DIMINISH AS THE FRONT
STALLS, WHICH MAY ALLOW FOG FOR SATURDAY AND SUNDAY MORNINGS.
PREV DISCUSSION... /ISSUED 143 AM EDT THU APR 11 2013/
AVIATION...
HIGH PRESSURE WILL REMAIN OVER THE WESTERN ATLANTIC WATERS
TODAY...AS LOW PRESSURE MOVES THROUGH THE GREAT LAKES. THIS WILL
ALLOW FOR A BREEZY TO WINDY SOUTHEAST WIND FLOW OVER THE SOUTH
FLORIDA TAF SITES TONIGHT WITH SPEEDS BETWEEN 15 TO 20 KNOTS WITH
GUSTS UP TO 28 KTS. THE SOUTHEAST WIND FLOW WILL CONTINUE
TONIGHT...BUT THE SPEEDS WILL DECREASE TO 10 KNOTS OR LESS AT THE
TAF SITES OVER SOUTH FLORIDA.
THE EAST COAST TAF SITES COULD SEE A SHOWER OR TWO ON THE
SOUTHEAST WIND FLOW TODAY...BUT THE COVERAGE AND DURATION WILL BE
FEW AND FAR BETWEEN. SO WILL LEAVE THE EAST COAST TAF SITES DRY AT
THIS TIME FOR TODAY INTO TONIGHT. KAPF TAF SITE COULD SEE SOME
SHOWERS IN THE AREA WITH MORE COVERAGE. SO HAVE ADDED VCSH TO KAPF
TAF SITE AFTER 15Z FOR TODAY.
THE CEILING AND VIS WILL ALSO REMAIN IN THE VFR CONDITIONS FOR
TODAY INTO TONIGHT FOR ALL OF THE TAF SITES.
AVIATION...54/BNB
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 73 84 72 84 / 20 40 20 50
FORT LAUDERDALE 75 84 74 84 / 20 30 20 50
MIAMI 74 85 74 85 / 20 30 20 50
NAPLES 71 83 70 83 / 20 20 20 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...HIGH RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR COASTAL
BROWARD-COASTAL MIAMI DADE-COASTAL PALM BEACH.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...85/AG
AVIATION/RADAR...17/ERA
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
227 PM EDT THU APR 11 2013
.UPDATE...
ISSUED AT 215 PM EDT THU APR 11 2013
HOURLY SKY...TEMPS AND DEWPOINTS HAVE BEEN FRESHENED UP FOR THE NEXT
FEW HOURS THIS AFTERNOON. SOME THINNER CIRRUS IS CURRENTLY WORKING
ACROSS THE CWA AT THIS POINT...ESPECIALLY EAST OF INTERSTATE 75 AND
TEMPS IN MANY LOCATIONS ARE PROBABLY NEARING DAYTIME HIGHS AS CU HAS
BEGUN TO DEVELOP. THE LATEST RADAR IMAGERY AND TRENDS INDICATE THAT
CONVECTION HAS BEEN SLOW TO INTENSIFY OVER MIDDLE TN AND CENTRAL KY.
HOWEVER...GIVEN CURRENT DEGREE OF SUNSHINE OVER MUCH OF THE AREA...
SOME INTENSIFICATION SHOULD OCCUR AS CONVECTION WORKS INTO THE
REGION LATE THIS AFTERNOON AND EVENING. AT THE LEAST THERE WILL BE
GUSTY WINDS WITH AN ANTICIPATED LINE OF CONVECTION AND CHANCES FOR A
FEW SEVERE THUNDERSTORMS ALONG THE LINE AS IT WORKS INTO EASTERN KY.
THE REGION REMAINS IN A SLIGHT RISK OF SEVERE THUNDERSTORMS AND
TIMING INTO LOCATIONS WEST OF I75...AROUND OR SHORTLY AFTER 5 PM
STILL LOOKS ON TARGET.
UPDATE ISSUED AT 1140 AM EDT THU APR 11 2013
DEBRIS CLOUD COVER FROM CONVECTION THAT OCCURRED AND IS OCCURRING
CLOSER TO THE APPROACHING BOUNDARY CONTINUES TO MOVE ACROSS THE
REGION. THIS IS LIMITING HEATING FROM WHAT THE POTENTIAL WOULD BE FOR
THIS TIME IN APRIL WITH A STRONG SUN ANGLE. DEWPOINTS WILL GRADUALLY
INCREASE AS WELL AND THEY ARE IN THE 50S...BUT UPPER 50S TO LOWER 60S
DEWPOINTS ARE GENERALLY CLOSER TO THE APPROACHING SFC COLD FRONT AND
FROM ABOUT THE OH RIVER AND NORTH. ANOTHER CONSIDERATION IS THE
SHORTWAVE MOVING FROM THE SOUTHERN PLAINS INTO THE LOWER MS VALLEY
REGION TOWARD AREAS WHERE MOISTURE IS DEEPER. CONVECTION THERE MAY
BECOME RATHER WIDESPREAD AND LIMIT MOISTURE TRANSPORT INTO THE REGION
SOMEWHAT AS WELL. HOWEVER...THE SYSTEM IS STILL EXPECTED TO BE RATHER
DYNAMIC AND SFC LOWS TRACKING BY TO OUR NORTH AND WEST DURING DAYTIME
TO EVENING TIMEFRAME IS A PATTERN THAT OFTEN TIMES PRODUCES AT LEAST
SOME SEVERE WEATHER IN EASTERN KY.
THE REGION REMAINS IN A SLIGHT RISK AREA FOR SEVERE THUNDERSTORMS
LATER TODAY...WITH PROBABILITIES GENERALLY GREATER TO OUR
SOUTH...ESPECIALLY GULF COAST STATES. A COMBINATION OF EXTRAPOLATION
OF SAT IMAGERY AND MODEL FORECASTS GENERALLY POINTS TOWARD THE LEAST
CLOUD COVER OVER THE NEXT FEW HOURS GENERALLY ALONG AND SOUTH OF A
LINE FROM MCCREARY COUNTY TO LOZ TO JKL TO K22 SOUTH AND EAST TOWARD
THE VA BORDER. THIS REGION SHOULD GET THE WARMEST THIS
AFTERNOON...BUT DEEPER MIXING WILL ALSO TEND TO DROP TO OR HOLD
DEWPOINTS IN THE LOWER TO MID 50S...BUT TEMPS IN LOWER ELEVATIONS IN
THIS AREA SHOULD REACH INTO THE 80 TO 85 RANGE ON AVERAGE. THIS
HEATING SHOULD ALLOW CAPE TO REACH THE 500 TO 1000 J/KG RANGE LATE
THIS AFTERNOON OR EARLY THIS EVENING AND THE APPROACH OF THE FRONT
AND UPPER LEVEL TROUGH SHOULD LEAD TO DEVELOPMENT OR RE-
INTENSIFICATION OF CONVECTION ALONG OR JUST AHEAD OF THE COLD FRONT
FROM VERY LATE AFTERNOON THROUGH THIS EVENING OR ABOUT 5 PM AND
AFTER. ALL FACTORS CONSIDERED SEEMS TO POINT TOWARD ISOLATED TO
SCATTERED SHOWERS OR ORDINARY THUNDERSTORMS IN THE WESTERN AND
NORTHWESTERN LOCATIONS FROM MID TO LATE AFTERNOON...WITH A LINE OF
GUSTY SHOWERS WITH SOME THUNDERSTORMS...WITH THE POTENTIAL FOR SOME
DAMAGING WIND GUSTS. SHEAR IS SUFFICIENT THAT IF THE BOUNDARY LAYER
CAN BECOME SUFFICIENTLY MOIST THAT A STRAY TORNADO ALONG THE LINE OF
CONVECTION CANNOT BE COMPLETELY RULED OUT. IF A STORM OR TWO WERE TO
ROTATE THAN SOME LARGE HAIL WOULD BE POSSIBLE...BUT THIS SHOULD BE
VERY ISOLATED...WITH ANY HAIL THAT OCCURS EXPECTED TO BE ALONG THE
LINES OF SUB SEVERE LEVELS.
THE GRIDS AND ZFP WERE UPDATED TO REFINE TIMING BASED ON CURRENT
OBSERVED TRENDS AND LATEST MODEL GUIDANCE AS WELL AS TO ADJUST SKY
AND TEMPS AS NOTED ABOVE.
UPDATE ISSUED AT 650 AM EDT THU APR 11 2013
STARTING TO SEE A FEW MID LEVEL RETURNS CREEPING INTO THE SOUTHWEST
PORTION OF THE AREA. HOWEVER...BASES REMAIN MUCH TOO HIGH TO ALLOW
FOR AND PRECIPITATION REACHING THE GROUND. PRECIPITATION IS
ATTEMPTING TO PUSH INTO CENTRAL KENTUCKY THIS MORNING...BUT IS MAKING
VERY SLOW PROGRESS. THE LATEST RAP AND NAM SUGGEST A LATER ONSET OF
PRECIPITATION TODAY...POSSIBLY HOLDING OFF UNTIL 7 OR 8 PM THIS
EVENING FOR MUCH OF THE AREA. THE I-75 CORRIDOR MAY SEE THINGS START
A BIT EARLY TOWARDS 5 OR 6 PM. THESE TRENDS MAY NEED TO BE WATCHED.
WITH INSTABILITY ALREADY IN QUESTION...A LATER ONSET TOWARDS MID TO
LATE EVENING MAY LIMIT THE SEVERE THREAT AS INSTABILITY MAY SIMPLY
NOT BE THERE. IN FACT...THE LATEST HRRR SHOWS PRETTY ROBUST
CONVECTION TO THE SOUTH OF THE AREA BY MID AFTERNOON...SUGGESTING
THAT THE EARLIER ASSUMPTION ABOUT STORMS TO THE SOUTH ROBBING US OF
OUR INSTABILITY MAY BE TRUE. THESE TRENDS WILL HAVE TO BE MONITORED
THIS MORNING. CLEARLY...THIS IS NOT A CLEAR CUT SCENARIO FOR SEVERE
WEATHER. HAVE MADE SOME MINOR TWEAKS TO THE LATEST
TEMPERATURE/DEWPOINT CURVES...AND ADJUSTED SLIGHTLY THE ONSET OF
PRECIPITATION. NO NEED TO UPDATE THE FORECAST THROUGH.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 316 AM EDT THU APR 11 2013
STRONG COLD FRONT CURRENTLY EXTENDS FROM NORTHERN INDIANA...SOUTHWARD
INTO FAR WESTERN KENTUCKY. A LINE OF SHOWERS AND STORMS CONTINUES TO
PUSH EAST ALONG THIS FRONTAL BOUNDARY. MODELS ARE ALL IN PRETTY GOOD
AGREEMENT WITH THE POSITION AND TIMING OF THIS FRONT AS IT CROSSES
EASTERN KENTUCKY LATER TODAY. UNIDIRECTIONAL WIND SHEAR IS SUFFICIENT
TO WARRANT A WIND THREAT WITH ANY THUNDERSTORMS THAT DEVELOP. LCL`S
MAY GET LOW ENOUGH IN THE CUMBERLAND PLATEAU TO SUPPORT AN ISOLATED
TORNADO...BUT THOSE LCL`S GO WAY UP AS YOU GO NORTH AND EAST. ONSET
FOR PRECPITATION SHOULD BE SOMETIME AFTER 2 PM FOR MOST AREAS TODAY.
THE BIG QUESTION SURROUNDING SEVERE POTENTIAL IS WHETHER ENOUGH
INSTABILITY WILL EXISTS TO SUPPORT THUNDERSTORMS WITH STRONG
DOWNDRAFTS. USING SFC BASED PARCEL OF 80/58 PRODUCES AROUND 900J/KG
OF SBCAPE. ALTHOUGH THIS IS MARGINAL...IT SHOULD BE SUFFICIENT TO
SUPPORT THUNDERSTORMS AND THUS WE COULD SEE SOME STRAY DAMAGING WIND
GUSTS. THUS...WILL MAINTAIN THE SEVERE THREAT WORDING IN THE HWO. THE
POTENTIAL DOES EXIST THAT CONVECTION DEVELOPING TO OUR SOUTH LATER
THIS AFTERNOON COULD ROB EASTERN KENTUCKY AND LIMIT THE SEVERE THREAT
OVER THE AREA. HOWEVER...THIS WOULD BE TOUGH TO BASE A FORECAST
ON...SO GOING TO MAINTAIN THE SEVERE THREAT.
SEVERE THREAT WILL COME TO AN END BY MIDNIGHT AS COLD FRONT PUSHES
EAST OUT OF THE AREA. RAIN WILL EVENTUALLY END FROM WEST TO EAST
OVERNIGHT. SYSTEM SHOULD BE PROGRESSIVE ENOUGH TO LIMIT ANY
SIGNIFICANT FLOODING ISSUE...ESPECIALLY WITH THE LACK OF RECENT
RAINFALL. SIGNIFICANTLY COOLER WEATHER WILL RETURN TO THE AREA LATE
TONIGHT. THE MORE SIGNIFICANT COLD AIR STAYS TO OUR NORTHWEST ON
FRIDAY. ALTHOUGH TEMPERATURES WILL BE COOLER...AFTERNOON READINGS MAY
STILL CLIMB INTO THE LOWER 60S UNDER SUNSHINE. SOME LOW CLOUDS MAY
START THE DAY...BUT GUSTY SOUTHWEST WINDS SHOULD ERODE THESE CLOUDS
FAIRLY QUICKLY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU APR 11 2013
THE MODELS ARE IN REASONABLY GOOD AGREEMENT THROUGH THE EXTENDED AND
ONLY START TO SIGNIFICANTLY DIVERGE TOWARD THE END. THE ALL AGREE
THAT A DEEP CLOSED LOW OVER THE GREAT LAKES WILL ROTATE OUT OF THE
AREA TO THE NORTHEAST. THIS PROCESS IS FACILITATED BY A DECENT
SHORTWAVE THAT WILL TRACK THROUGH THE OHIO VALLEY ON SATURDAY...WITH
THE ECMWF REPRESENTING A GOOD COMPROMISE BETWEEN THE SLOWER GEM AND
FASTER GFS. HEIGHTS WILL RISE IN THE WAKE OF THE UPPER LOW/S
DEPARTURE WITH A HINT OF RIDGING TAKING PLACE TO CLOSE OUT THE
WEEKEND. TO THE SOUTH OF THE AREA...A LOOSE CLUSTER OF ENERGY WILL
DRIFT PAST LATER THAT NIGHT AND MAY BE ENOUGH TO HAVE AN EFFECT ON
THE SENSIBLE WEATHER OF SOUTHEAST KENTUCKY. OTHERWISE...RENEWED
RIDGING WILL TAKE SHAPE OVER SOUTHEAST PORTION OF THE NATION
RESULTING IN RISING HEIGHTS THROUGH TUESDAY. THE MODELS ARE HINTING
THAT THIS PATTERN MAY BREAK DOWN LATER IN THE WEEK AS TROUGHING OUT
WEST STARTS TO MOVE EAST INTO THE PLAINS ON WEDNESDAY...FASTEST IN
THE GFS WHEN COMPARED TO THE 12Z ECMWF. IN ADDITION...A FEW WEAKER
PATCHES OF ENERGY WILL LIKELY START TO MAKE THEIR WAY THROUGH THE
REGION OUT AHEAD OF THE LARGER...INBOUND...SYSTEM.
SENSIBLE WEATHER WILL FEATURE A BRIEF COOL DOWN FOR THE START OF THE
WEEKEND AS HIGH PRESSURE SETTLES INTO THE AREA FOLLOWING THE LARGER
LOW PRESSURE SYSTEM EXITING TO THE NORTHEAST. THIS HIGH WILL QUICKLY
MODERATE...THOUGH...SO THAT EACH AFTERNOON WE CAN EXPECT
TEMPERATURES A FEW DEGREES HIGHER THAN THE PREVIOUS ONE THROUGH
TUESDAY. MORE IN THE WAY OF CLOUDS AND A BETTER POTENTIAL FOR
SHOWERS AND THUNDERSTORMS...LIKE A SUMMER TIME DIURNAL CONVECTIVE
PATTERN...MAY KEEP TEMPS A BIT LOWER ON WEDNESDAY THAN TUESDAY. THIS
POTENTIAL AND THE UNCERTAINTY OF THE TIMING FOR THE NEXT SYSTEM
MIDWEEK CALLS FOR LOW TO MID RANGE POP CHANCES FOR WEDNESDAY. THE
REST OF THE EXTENDED WILL LIKELY BE DRY...THOUGH CAN/T RULE OUT A
STRAY SHOWER EARLY MONDAY AS A WEAK SFC WAVE PASSES BY TO THE
SOUTH.
THE CR GRID LOAD CAME IN PRETTY DECENT...BUT DID NUDGE DOWN POPS
TUESDAY AND WEDNESDAY MORE TOWARDS THE 12Z ECMWF. ALSO MAKE SOME
SIGNIFICANT TERRAIN BASED ADJUSTMENTS FOR LOWS EACH NIGHT...
ANTICIPATING DECENT RIDGE TO VALLEY SPLITS THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 225 PM EDT THU APR 11 2013
VFR CONDITIONS REMAIN IN PLACE AHEAD OF THE BOUNDARY IN EASTERN KY.
CU AROUND 5 TO 6KFT AGL HAS BEGUN TO DEVELOP. UNTIL CONVECTION
ARRIVES...VFR VIS AND CEILINGS ARE ANTICIPATED. AS A COLD FRONT
APPROACHES...WINDS WILL BECOME MORE SOUTH TO SOUTHWEST OVER THE NEXT
FEW HOURS...AND MAY BE ACCOMPANIED BY GUSTS UP TO 20 KT OR
SO...ESPECIALLY AT LOZ AND SME. SHRA AND SOME TSRA...SHOULD PUSH INTO
THE LAKE CUMBERLAND REGION AND THEN EASTERN KENTUCKY AS EARLY AS 21Z
AT LOCATIONS SUCH AS SME AND LOZ. CIGS SHOULD REMAIN ELEVATED
INITIALLY...BUT AS THE ATMOSPHERE MOISTENS OVER THE FIRST 3 TO 5
HOURS AFTER CONVECTION ARRIVES CIGS SHOULD DETERIORATE TO MVFR..THEN
IFR AND FINALLY APPROACH AIRPORT MINS AT SOME POINT DURING THE 0Z TO
13Z WINDOW. A FEW SEVERE WIND GUSTS ARE POSSIBLE WITH ANY THUNDERSTORMS
21Z THROUGH 4Z. BEHIND THE FRONT AND INITIAL LINE OF SHRA AND TSRA...
RAIN SHOULD PERSIST FOR A FEW HOURS...BUT EXIT THE AREA BETWEEN 6Z
AND 12Z. WE COULD EXPERIENCE STRATUS BUILDDOWN OR A BIT OF CLEARING
THAT MIGHT LEAD TO SOME FOG. THERE IS UNCERTAINTY AS TO HOW LOW VIS
MIGHT DROP WITH THIS AND DEPENDS ON DEGREE OF SATURATION. THE STRATUS
OR FOG SHOULD MIX INTO MVFR CU BETWEEN 12Z AND 16Z...AND THEN SOME CU IN
THE VFR RANGE AROUND 4 TO 5KFT AGL.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...JP
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON KY
1140 AM EDT THU APR 11 2013
.UPDATE...
ISSUED AT 1140 AM EDT THU APR 11 2013
DEBRIS CLOUD COVER FROM CONVECTION THAT OCCURRED AND IS OCCURRING
CLOSER TO THE APPROACHING BOUNDARY CONTINUES TO MOVE ACROSS THE
REGION. THIS IS LIMITING HEATING FROM WHAT THE POTENTIAL WOULD BE FOR
THIS TIME IN APRIL WITH A STRONG SUN ANGLE. DEWPOINTS WILL GRADUALLY
INCREASE AS WELL AND THEY ARE IN THE 50S...BUT UPPER 50S TO LOWER 60S
DEWPOINTS ARE GENERALLY CLOSER TO THE APPROACHING SFC COLD FRONT AND
FROM ABOUT THE OH RIVER AND NORTH. ANOTHER CONSIDERATION IS THE
SHORTWAVE MOVING FROM THE SOUTHERN PLAINS INTO THE LOWER MS VALLEY
REGION TOWARD AREAS WHERE MOISTURE IS DEEPER. CONVECTION THERE MAY
BECOME RATHER WIDESPREAD AND LIMIT MOISTURE TRANSPORT INTO THE REGION
SOMEWHAT AS WELL. HOWEVER...THE SYSTEM IS STILL EXPECTED TO BE RATHER
DYNAMIC AND SFC LOWS TRACKING BY TO OUR NORTH AND WEST DURING DAYTIME
TO EVENING TIMEFRAME IS A PATTERN THAT OFTEN TIMES PRODUCES AT LEAST
SOME SEVERE WEATHER IN EASTERN KY.
THE REGION REMAINS IN A SLIGHT RISK AREA FOR SEVERE THUNDERSTORMS
LATER TODAY...WITH PROBABILITIES GENERALLY GREATER TO OUR
SOUTH...ESPECIALLY GULF COAST STATES. A COMBINATION OF EXTRAPOLATION
OF SAT IMAGERY AND MODEL FORECASTS GENERALLY POINTS TOWARD THE LEAST
CLOUD COVER OVER THE NEXT FEW HOURS GENERALLY ALONG AND SOUTH OF A
LINE FROM MCCREARY COUNTY TO LOZ TO JKL TO K22 SOUTH AND EAST TOWARD
THE VA BORDER. THIS REGION SHOULD GET THE WARMEST THIS
AFTERNOON...BUT DEEPER MIXING WILL ALSO TEND TO DROP TO OR HOLD
DEWPOINTS IN THE LOWER TO MID 50S...BUT TEMPS IN LOWER ELEVATIONS IN
THIS AREA SHOULD REACH INTO THE 80 TO 85 RANGE ON AVERAGE. THIS
HEATING SHOULD ALLOW CAPE TO REACH THE 500 TO 1000 J/KG RANGE LATE
THIS AFTERNOON OR EARLY THIS EVENING AND THE APPROACH OF THE FRONT
AND UPPER LEVEL TROUGH SHOULD LEAD TO DEVELOPMENT OR RE-
INTENSIFICATION OF CONVECTION ALONG OR JUST AHEAD OF THE COLD FRONT
FROM VERY LATE AFTERNOON THROUGH THIS EVENING OR ABOUT 5 PM AND
AFTER. ALL FACTORS CONSIDERED SEEMS TO POINT TOWARD ISOLATED TO
SCATTERED SHOWERS OR ORDINARY THUNDERSTORMS IN THE WESTERN AND
NORTHWESTERN LOCATIONS FROM MID TO LATE AFTERNOON...WITH A LINE OF
GUSTY SHOWERS WITH SOME THUNDERSTORMS...WITH THE POTENTIAL FOR SOME
DAMAGING WIND GUSTS. SHEAR IS SUFFICIENT THAT IF THE BOUNDARY LAYER
CAN BECOME SUFFICIENTLY MOIST THAT A STRAY TORNADO ALONG THE LINE OF
CONVECTION CANNOT BE COMPLETELY RULED OUT. IF A STORM OR TWO WERE TO
ROTATE THAN SOME LARGE HAIL WOULD BE POSSIBLE...BUT THIS SHOULD BE
VERY ISOLATED...WITH ANY HAIL THAT OCCURS EXPECTED TO BE ALONG THE
LINES OF SUB SEVERE LEVELS.
THE GRIDS AND ZFP WERE UPDATED TO REFINE TIMING BASED ON CURRENT
OBSERVED TRENDS AND LATEST MODEL GUIDANCE AS WELL AS TO ADJUST SKY
AND TEMPS AS NOTED ABOVE.
UPDATE ISSUED AT 650 AM EDT THU APR 11 2013
STARTING TO SEE A FEW MID LEVEL RETURNS CREEPING INTO THE SOUTHWEST
PORTION OF THE AREA. HOWEVER...BASES REMAIN MUCH TOO HIGH TO ALLOW
FOR AND PRECIPITATION REACHING THE GROUND. PRECIPITATION IS
ATTEMPTING TO PUSH INTO CENTRAL KENTUCKY THIS MORNING...BUT IS MAKING
VERY SLOW PROGRESS. THE LATEST RAP AND NAM SUGGEST A LATER ONSET OF
PRECIPITATION TODAY...POSSIBLY HOLDING OFF UNTIL 7 OR 8 PM THIS
EVENING FOR MUCH OF THE AREA. THE I-75 CORRIDOR MAY SEE THINGS START
A BIT EARLY TOWARDS 5 OR 6 PM. THESE TRENDS MAY NEED TO BE WATCHED.
WITH INSTABILITY ALREADY IN QUESTION...A LATER ONSET TOWARDS MID TO
LATE EVENING MAY LIMIT THE SEVERE THREAT AS INSTABILITY MAY SIMPLY
NOT BE THERE. IN FACT...THE LATEST HRRR SHOWS PRETTY ROBUST
CONVECTION TO THE SOUTH OF THE AREA BY MID AFTERNOON...SUGGESTING
THAT THE EARLIER ASSUMPTION ABOUT STORMS TO THE SOUTH ROBBING US OF
OUR INSTABILITY MAY BE TRUE. THESE TRENDS WILL HAVE TO BE MONITORED
THIS MORNING. CLEARLY...THIS IS NOT A CLEAR CUT SCENARIO FOR SEVERE
WEATHER. HAVE MADE SOME MINOR TWEAKS TO THE LATEST
TEMPERATURE/DEWPOINT CURVES...AND ADJUSTED SLIGHTLY THE ONSET OF
PRECIPITATION. NO NEED TO UPDATE THE FORECAST THROUGH.
&&
.SHORT TERM...(TODAY THROUGH FRIDAY)
ISSUED AT 316 AM EDT THU APR 11 2013
STRONG COLD FRONT CURRENTLY EXTENDS FROM NORTHERN INDIANA...SOUTHWARD
INTO FAR WESTERN KENTUCKY. A LINE OF SHOWERS AND STORMS CONTINUES TO
PUSH EAST ALONG THIS FRONTAL BOUNDARY. MODELS ARE ALL IN PRETTY GOOD
AGREEMENT WITH THE POSITION AND TIMING OF THIS FRONT AS IT CROSSES
EASTERN KENTUCKY LATER TODAY. UNIDIRECTIONAL WIND SHEAR IS SUFFICIENT
TO WARRANT A WIND THREAT WITH ANY THUNDERSTORMS THAT DEVELOP. LCL`S
MAY GET LOW ENOUGH IN THE CUMBERLAND PLATEAU TO SUPPORT AN ISOLATED
TORNADO...BUT THOSE LCL`S GO WAY UP AS YOU GO NORTH AND EAST. ONSET
FOR PRECPITATION SHOULD BE SOMETIME AFTER 2 PM FOR MOST AREAS TODAY.
THE BIG QUESTION SURROUNDING SEVERE POTENTIAL IS WHETHER ENOUGH
INSTABILITY WILL EXISTS TO SUPPORT THUNDERSTORMS WITH STRONG
DOWNDRAFTS. USING SFC BASED PARCEL OF 80/58 PRODUCES AROUND 900J/KG
OF SBCAPE. ALTHOUGH THIS IS MARGINAL...IT SHOULD BE SUFFICIENT TO
SUPPORT THUNDERSTORMS AND THUS WE COULD SEE SOME STRAY DAMAGING WIND
GUSTS. THUS...WILL MAINTAIN THE SEVERE THREAT WORDING IN THE HWO. THE
POTENTIAL DOES EXIST THAT CONVECTION DEVELOPING TO OUR SOUTH LATER
THIS AFTERNOON COULD ROB EASTERN KENTUCKY AND LIMIT THE SEVERE THREAT
OVER THE AREA. HOWEVER...THIS WOULD BE TOUGH TO BASE A FORECAST
ON...SO GOING TO MAINTAIN THE SEVERE THREAT.
SEVERE THREAT WILL COME TO AN END BY MIDNIGHT AS COLD FRONT PUSHES
EAST OUT OF THE AREA. RAIN WILL EVENTUALLY END FROM WEST TO EAST
OVERNIGHT. SYSTEM SHOULD BE PROGRESSIVE ENOUGH TO LIMIT ANY
SIGNIFICANT FLOODING ISSUE...ESPECIALLY WITH THE LACK OF RECENT
RAINFALL. SIGNIFICANTLY COOLER WEATHER WILL RETURN TO THE AREA LATE
TONIGHT. THE MORE SIGNIFICANT COLD AIR STAYS TO OUR NORTHWEST ON
FRIDAY. ALTHOUGH TEMPERATURES WILL BE COOLER...AFTERNOON READINGS MAY
STILL CLIMB INTO THE LOWER 60S UNDER SUNSHINE. SOME LOW CLOUDS MAY
START THE DAY...BUT GUSTY SOUTHWEST WINDS SHOULD ERODE THESE CLOUDS
FAIRLY QUICKLY.
.LONG TERM...(FRIDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 316 AM EDT THU APR 11 2013
THE MODELS ARE IN REASONABLY GOOD AGREEMENT THROUGH THE EXTENDED AND
ONLY START TO SIGNIFICANTLY DIVERGE TOWARD THE END. THE ALL AGREE
THAT A DEEP CLOSED LOW OVER THE GREAT LAKES WILL ROTATE OUT OF THE
AREA TO THE NORTHEAST. THIS PROCESS IS FACILITATED BY A DECENT
SHORTWAVE THAT WILL TRACK THROUGH THE OHIO VALLEY ON SATURDAY...WITH
THE ECMWF REPRESENTING A GOOD COMPROMISE BETWEEN THE SLOWER GEM AND
FASTER GFS. HEIGHTS WILL RISE IN THE WAKE OF THE UPPER LOW/S
DEPARTURE WITH A HINT OF RIDGING TAKING PLACE TO CLOSE OUT THE
WEEKEND. TO THE SOUTH OF THE AREA...A LOOSE CLUSTER OF ENERGY WILL
DRIFT PAST LATER THAT NIGHT AND MAY BE ENOUGH TO HAVE AN EFFECT ON
THE SENSIBLE WEATHER OF SOUTHEAST KENTUCKY. OTHERWISE...RENEWED
RIDGING WILL TAKE SHAPE OVER SOUTHEAST PORTION OF THE NATION
RESULTING IN RISING HEIGHTS THROUGH TUESDAY. THE MODELS ARE HINTING
THAT THIS PATTERN MAY BREAK DOWN LATER IN THE WEEK AS TROUGHING OUT
WEST STARTS TO MOVE EAST INTO THE PLAINS ON WEDNESDAY...FASTEST IN
THE GFS WHEN COMPARED TO THE 12Z ECMWF. IN ADDITION...A FEW WEAKER
PATCHES OF ENERGY WILL LIKELY START TO MAKE THEIR WAY THROUGH THE
REGION OUT AHEAD OF THE LARGER...INBOUND...SYSTEM.
SENSIBLE WEATHER WILL FEATURE A BRIEF COOL DOWN FOR THE START OF THE
WEEKEND AS HIGH PRESSURE SETTLES INTO THE AREA FOLLOWING THE LARGER
LOW PRESSURE SYSTEM EXITING TO THE NORTHEAST. THIS HIGH WILL QUICKLY
MODERATE...THOUGH...SO THAT EACH AFTERNOON WE CAN EXPECT
TEMPERATURES A FEW DEGREES HIGHER THAN THE PREVIOUS ONE THROUGH
TUESDAY. MORE IN THE WAY OF CLOUDS AND A BETTER POTENTIAL FOR
SHOWERS AND THUNDERSTORMS...LIKE A SUMMER TIME DIURNAL CONVECTIVE
PATTERN...MAY KEEP TEMPS A BIT LOWER ON WEDNESDAY THAN TUESDAY. THIS
POTENTIAL AND THE UNCERTAINTY OF THE TIMING FOR THE NEXT SYSTEM
MIDWEEK CALLS FOR LOW TO MID RANGE POP CHANCES FOR WEDNESDAY. THE
REST OF THE EXTENDED WILL LIKELY BE DRY...THOUGH CAN/T RULE OUT A
STRAY SHOWER EARLY MONDAY AS A WEAK SFC WAVE PASSES BY TO THE
SOUTH.
THE CR GRID LOAD CAME IN PRETTY DECENT...BUT DID NUDGE DOWN POPS
TUESDAY AND WEDNESDAY MORE TOWARDS THE 12Z ECMWF. ALSO MAKE SOME
SIGNIFICANT TERRAIN BASED ADJUSTMENTS FOR LOWS EACH NIGHT...
ANTICIPATING DECENT RIDGE TO VALLEY SPLITS THROUGH THE EXTENDED.
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 650 AM EDT THU APR 11 2013
HIGH/MID CLOUDS CONTINUE TO STREAM EAST ACROSS THE AREA. VFR
CONDITIONS SHOULD CONTINUE AT THE TAF SITES INTO MIDDAY TODAY. WINDS
WILL TURN GUSTY OUT OF THE SOUTH-SOUTHWEST BY LATE MORNING INTO THE
AFTERNOON AS A COLD FRONT ARRIVES FROM THE WEST. SHOWERS AND
THUNDERSTORMS SHOULD PUSH INTO CENTRAL AND EASTERN KENTUCKY AS EARLY
AS 20Z OR 21Z. CIGS SHOULD REMAIN ELEVATED INITIALLY. A FEW SEVERE
WIND GUSTS ARE POSSIBLE WITH ANY THUNDERSTORMS TODAY. AS THE FRONT
PASSES THIS EVENING...LOW LEVEL MOISTURE WILL SURGE EAST ACROSS THE
AREA DROPPING CIGS TO MVFR...THEN EVENTUALLY IFR LATER ON. RAIN
SHOULD PERSIST INTO THE FIRST HALF OF TONIGHT AS WELL...WHICH COULD
AID IN SOME PATCHY FOG FORMATION RESTRICTING VISIBILITIES AT TIMES.
STRATUS BUILD DOWN COULD OCCUR ONTO THE RIDGES WHICH MAY DROP
VISIBILITIES TO A QUARTER MILE OR LESS ON THE RIDGETOPS TONIGHT.
CLEARLY...LESS THAN IDEAL FLYING CONDITIONS WILL BE FOUND ACROSS
EASTERN KENTUCKY TONIGHT.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...KAS
LONG TERM...GREIF
AVIATION...KAS
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1236 PM CDT THU APR 11 2013
.UPDATE...
ISSUED AT 1126 AM CDT THU APR 11 2013
CWFA WILL LIE UNDER CYCLONIC FLOW ALOFT WITH STRONG CAA PROGGED AT
850 HPA. KOAX HAD A TEMP OF -8C AT 1200 UTC THIS MORNING AND THE
850-HPA FRONT IS COMING THROUGH THE CENTER OF THE CWFA AS WE
SPEAK. WITH STRONG CAA AND MVFR CEILINGS CONTINUING THROUGH MID
AFTERNOON. THUS...HAVE LOWERED HI TEMPS AT LEAST A FEW DEGREES
AREAWIDE. IN ADDITION...HAVE ADDED PATCHY DRIZZLE FOR THE ENTIRE
CWA AND HAVE CUT CHC POPS BACK TO SCH POPS FOR ISOLATED SHOWERS
OVER NORTHEAST MISSOURI AND WEST-CENTRAL ILLINOIS. HESITANT TO
JUST GO WITH DRIZZLE/SPRINKLES OVER THIS REGION AND DROP
MEASURABLE POPS ALTOGETHER AS WV IMAGERY DOES HAVE A SHORTWAVE
UPSTREAM OVER NW MO AND LATEST HRRR GUIDANCE ALSO SUGGESTS
ISOLATED SHOWERS OVER THIS REGION UNDER THE COLD CORE 500-HPA
CYCLONE/STEEP MIDLEVEL LAPSE RATES ALOFT. ZONE UPDATE WILL BE OUT SHORTLY.
GOSSELIN
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 350 AM CDT THU APR 11 2013
LIGHT RAIN/DRIZZLE THAT IS LINGERING OVER THE METRO AREA INTO
ILLINOIS IS SHOWING SLOW PROGRESSION EASTWARD EARLY THIS MORNING.
ANY LINGERING LIGHT RAIN WILL END THIS MORNING AS ASCENT WEAKENS
OVER THE AREA. WILL KEEP MENTION OF ISOLATED/SCATTERED LIGHT
SHOWERS ALONG AND NORTH OF I-70 THIS AFTERNOON WHERE LOW LEVEL
MOISTURE WILL LINGER IN CYCLONIC FLOW. TEMPERATURES WILL ONLY SHOW
A SLIGHT INCREASE TODAY WITH MAINLY CLOUDY SKIES AND COLD AIR
ADVECTION. ONLY TWEAKED GOING HIGHS WHICH MATCH UP WELL WITH MOS
HIGHS/MODEL 2 METER TEMPERATURES.
BRITT
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM CDT THU APR 11 2013
UPPER LEVEL LOW AND ASSOCIATED SFC LOW OVER IA THIS EVNG WILL MOVE
NEWD INTO WI LATER TGT. IT APPEARS THAT MOST OF THE PRECIPITATION
IN THE WRAP AROUND MOISTURE WILL REMAIN N OF OUR FORECAST
AREA...ALTHOUGH THERE COULD BE A LITTLE LIGHT RAIN ACROSS NERN MO
AND W CNTRL IL...MAINLY THIS EVNG...POSSIBLY MIXED WITH A LITTLE
LIGHT SNOW LATE THIS EVNG. MUCH COLDER TEMPERATURES CAN BE
EXPECTED TGT WITH THE NAM AND ECMWF MODELS DROPPING THE -4 DEGREE
C ISOTHERM SEWD INTO SERN MO AND SWRN IL BY 12Z FRI...THE GFS
MODEL IS A LITTLE WARMER. LOWS TGT WILL LIKELY BE DOWN TO AROUND
THE FREEZING MARK ACROSS NERN AND CNTRL MO AS WELL AS W CNTRL IL.
BELOW NORMAL TEMPERATURES WILL CONINUE ON FRI WITH CLOUD COVER
CONTINUING ACROSS NERN MO AND W CNTRL IL INTO SWRN IL...BUT
PRECIPITATION REMAINING N-NE OF OUR AREA...MAINLY IN THE GREAT
LAKES REGION IN THE VICINITY OF THE UPPER/SFC LOW. A NW FLOW
SHORTWAVE WILL DROP SEWD THROUGH IA AND NRN IL FRI NGT BRINGING A
REINFORCING SHOT OF COLD AIR INTO NERN MO AND W CNTRL IL. WITH
POTENTIALLY LESS CLOUD COVER AND WEAKER SFC WINDS THE LOWS FRI NGT
WILL LIKELY BE LOWER THAN TGT...RANGING FROM THE UPPER 20S IN
NERN MO TO THE MID 30S IN SERN MO. WILL HOLD OFF ON ANY
FREEZE/FROST HEADLINES/PRODUCTS FOR NOW BUT LATER SHIFTS MAY NEED
TO ISSUE A FREEZE WARNING FOR PARTS OF OUR AREA TGT AND/OR FRI
NGT AS THE GROWING SEASON HAS BEGUN. A WARMING TREND WILL BEGIN
SAT AFTN AS THE SFC/LOW LEVEL WINDS BECOME S/SWLY BY 00Z SUN AS
THE SFC/850 MB RIDGE SHIFTS E-SE OF OUR AREA...AND THE UPPER LEVEL
HEIGHTS BEGIN TO RISE. THE PERSISTENT LOW LEVEL CLOUDS SHOULD ALSO
FINALLY ADVECT WELL NE OF OUR AREA BY SAT...ALTHOUGH IT APPEARS
THAT MID LEVEL...WAA CLOUDS WILL BE MOVING EWD INTO OUR AREA SAT
AFTN. STILL LOOKS LIKE THERE WILL BE THE POTENTIAL FOR ELEVATED
CONVECTION...MAINLY LATE SAT NGT AND MAINLY ACROSS NERN MO AND W
CNTRL IL...AS A STRENGTHENING SWLY LOW LEVEL JET BRINGS STRONG
LOW-MID LEVEL WAA TO THIS AREA ALONG WITH INCREASING LOW LEVEL
MOISTURE. THE CHANCE OF RAIN WILL CONTINUE ACROSS NERN MO AND W
CNTRL IL ON SUN AS AN UPPER LEVEL AND ASSOCIATED SFC LOW MOVE
NEWD THROUGH THE NRN PLAINS DRAGGING A COLD FRONT SLOWLY SEWD INTO
THE NWRN PORTION OF OUR FORECAST AREA. THIS FRONT SHOULD SAG SLOWLY
S-SEWD THROUGH OUR FORECAST AREA SUN NGT AND MON. THE GFS MODEL IS A
LITTLE MORE PROGESSIVE WITH THIS FRONT THAN THE ECMWF MODEL. IT
APPEARS THAT MOST OF THE PRECIPITATION WILL BE POST FRONTAL...BUT
WITH A LOT OF UNCERTAINTY WITH THE EXACT PLACEMENT OF THIS FRONT
WILL NEED TO BROADBRUSH CHANCE POPS ACROSS THE ENTIRE FORECAST
AREA MON NGT THROUGH TUE NGT. THE COOLEST TEMPERATURES SHOULD BE
ACROSS NERN MO WELL BEHIND THE COLD FRONT. THE BEST CHANCE OF RAIN
IS EXPECTED ON WED AND WED NGT AS A SFC LOW DEVELOPS ALONG THE
FRONT AS AN UPPER LEVEL TROUGH APPROACHES. THE ECMWF MODEL KEEPS
THE MAIN SFC LOW N OF OUR AREA MORE TYPICAL OF SPRING...WHILE THE
GFS MODEL IS FURTHER S WITH THE TRACK OF THE SFC LOW...KEEPING IT
JUST S OF OUR AREA AND IS A COLDER SOLUTION.
GKS
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)
ISSUED AT 1224 PM CDT THU APR 11 2013
MAIN CONCERN FOR THE VALID TAF PERIOD IS CEILINGS. MVFR CEILINGS
WILL LIKELY HOLD STRONG INTO AT LEAST THE MID AFTERNOON HOURS AS
THE REGION IS UNDER PERSISTENT COLD/CYCLONIC FLOW ALOFT. WAS
PESSIMISTIC WITH TIMING OF CEILINGS CLIMBING ABOVE THE FUEL
ALTERNATE THRESHOLD OF 2000 FEET AS CEILINGS HAVE BEEN VERY
STUBBORN TO CLIMB THUS FAR TODAY. AM ALSO A BIT CONCERNED THAT
ONCE SUN GOES DOWN AND NOCTURNAL COOLING COMMENCES THAT CEILINGS
WILL HAVE A HARD TIME GETTING ABOVE MVFR...ESPECIALLY FOR THE
METRO TAFS AND QUINCY WHICH WILL BE IN CLOSER PROXIMITY TO
DEPARTING LOW PRESSURE SYSTEM. WINDS WILL STAY WESTERLY WITH SOME
GUSTS AROUND 20 KNOTS THIS AFTERNOON AND TOMORROW AS WELL.
SPECIFICS FOR KSTL...
MAIN CONCERN FOR THE VALID TAF PERIOD IS CEILINGS. MVFR CEILINGS
WILL LIKELY HOLD STRONG INTO AT LEAST THE MID AFTERNOON HOURS AS
THE REGION IS UNDER PERSISTENT COLD/CYCLONIC FLOW ALOFT. WAS
PESSIMISTIC WITH TIMING OF CEILINGS CLIMBING ABOVE THE FUEL
ALTERNATE THRESHOLD OF 2000 FEET AT LAMBERT AS CEILINGS HAVE BEEN
VERY STUBBORN TO CLIMB THUS FAR TODAY. AM ALSO A BIT CONCERNED
THAT ONCE SUN GOES DOWN AND NOCTURNAL COOLING COMMENCES THAT
CEILINGS WILL HAVE A HARD TIME GETTING ABOVE MVFR...BUT DUE TO LOW
CONFIDENCE IN THIS SCENARIO...HAVE ELECTED TO KEEP PREVIOUS
FORECAST GOINGN FOR NOW. WINDS WILL STAY WESTERLY WITH SOME GUSTS
AROUND 20 KNOTS THIS AFTERNOON BEFORE DIEING OFF THIS EVENING.
WINDS WILL INCREASE AND BECOME GUSTY AGAIN DURING THE DAY
TOMORROW.
GOSSELIN
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
1135 AM CDT THU APR 11 2013
.UPDATE...
ISSUED AT 1126 AM CDT THU APR 11 2013
CWFA WILL LIE UNDER CYCLONIC FLOW ALOFT WITH STRONG CAA PROGGED AT
850 HPA. KOAX HAD A TEMP OF -8C AT 1200 UTC THIS MORNING AND THE
850-HPA FRONT IS COMING THROUGH THE CENTER OF THE CWFA AS WE
SPEAK. WITH STRONG CAA AND MVFR CEILINGS CONTINUING THROUGH MID
AFTERNOON. THUS...HAVE LOWERED HI TEMPS AT LEAST A FEW DEGREES
AREAWIDE. IN ADDITION...HAVE ADDED PATCHY DRIZZLE FOR THE ENTIRE
CWA AND HAVE CUT CHC POPS BACK TO SCH POPS FOR ISOLATED SHOWERS
OVER NORTHEAST MISSOURI AND WEST-CENTRAL ILLINOIS. HESITANT TO
JUST GO WITH DRIZZLE/SPRINKLES OVER THIS REGION AND DROP
MEASURABLE POPS ALTOGETHER AS WV IMAGERY DOES HAVE A SHORTWAVE
UPSTREAM OVER NW MO AND LATEST HRRR GUIDANCE ALSO SUGGESTS
ISOLATED SHOWERS OVER THIS REGION UNDER THE COLD CORE 500-HPA
CYCLONE/STEEP MIDLEVEL LAPSE RATES ALOFT. ZONE UPDATE WILL BE OUT SHORTLY.
GOSSELIN
&&
.SHORT TERM...(THROUGH LATE THIS AFTERNOON)
ISSUED AT 350 AM CDT THU APR 11 2013
LIGHT RAIN/DRIZZLE THAT IS LINGERING OVER THE METRO AREA INTO
ILLINOIS IS SHOWING SLOW PROGRESSION EASTWARD EARLY THIS MORNING.
ANY LINGERING LIGHT RAIN WILL END THIS MORNING AS ASCENT WEAKENS
OVER THE AREA. WILL KEEP MENTION OF ISOLATED/SCATTERED LIGHT
SHOWERS ALONG AND NORTH OF I-70 THIS AFTERNOON WHERE LOW LEVEL
MOISTURE WILL LINGER IN CYCLONIC FLOW. TEMPERATURES WILL ONLY SHOW
A SLIGHT INCREASE TODAY WITH MAINLY CLOUDY SKIES AND COLD AIR
ADVECTION. ONLY TWEAKED GOING HIGHS WHICH MATCH UP WELL WITH MOS
HIGHS/MODEL 2 METER TEMPERATURES.
BRITT
.LONG TERM...(TONIGHT THROUGH WEDNESDAY)
ISSUED AT 350 AM CDT THU APR 11 2013
UPPER LEVEL LOW AND ASSOCIATED SFC LOW OVER IA THIS EVNG WILL MOVE
NEWD INTO WI LATER TGT. IT APPEARS THAT MOST OF THE PRECIPITATION
IN THE WRAP AROUND MOISTURE WILL REMAIN N OF OUR FORECAST
AREA...ALTHOUGH THERE COULD BE A LITTLE LIGHT RAIN ACROSS NERN MO
AND W CNTRL IL...MAINLY THIS EVNG...POSSIBLY MIXED WITH A LITTLE
LIGHT SNOW LATE THIS EVNG. MUCH COLDER TEMPERATURES CAN BE
EXPECTED TGT WITH THE NAM AND ECMWF MODELS DROPPING THE -4 DEGREE
C ISOTHERM SEWD INTO SERN MO AND SWRN IL BY 12Z FRI...THE GFS
MODEL IS A LITTLE WARMER. LOWS TGT WILL LIKELY BE DOWN TO AROUND
THE FREEZING MARK ACROSS NERN AND CNTRL MO AS WELL AS W CNTRL IL.
BELOW NORMAL TEMPERATURES WILL CONINUE ON FRI WITH CLOUD COVER
CONTINUING ACROSS NERN MO AND W CNTRL IL INTO SWRN IL...BUT
PRECIPITATION REMAINING N-NE OF OUR AREA...MAINLY IN THE GREAT
LAKES REGION IN THE VICINITY OF THE UPPER/SFC LOW. A NW FLOW
SHORTWAVE WILL DROP SEWD THROUGH IA AND NRN IL FRI NGT BRINGING A
REINFORCING SHOT OF COLD AIR INTO NERN MO AND W CNTRL IL. WITH
POTENTIALLY LESS CLOUD COVER AND WEAKER SFC WINDS THE LOWS FRI NGT
WILL LIKELY BE LOWER THAN TGT...RANGING FROM THE UPPER 20S IN
NERN MO TO THE MID 30S IN SERN MO. WILL HOLD OFF ON ANY
FREEZE/FROST HEADLINES/PRODUCTS FOR NOW BUT LATER SHIFTS MAY NEED
TO ISSUE A FREEZE WARNING FOR PARTS OF OUR AREA TGT AND/OR FRI
NGT AS THE GROWING SEASON HAS BEGUN. A WARMING TREND WILL BEGIN
SAT AFTN AS THE SFC/LOW LEVEL WINDS BECOME S/SWLY BY 00Z SUN AS
THE SFC/850 MB RIDGE SHIFTS E-SE OF OUR AREA...AND THE UPPER LEVEL
HEIGHTS BEGIN TO RISE. THE PERSISTENT LOW LEVEL CLOUDS SHOULD ALSO
FINALLY ADVECT WELL NE OF OUR AREA BY SAT...ALTHOUGH IT APPEARS
THAT MID LEVEL...WAA CLOUDS WILL BE MOVING EWD INTO OUR AREA SAT
AFTN. STILL LOOKS LIKE THERE WILL BE THE POTENTIAL FOR ELEVATED
CONVECTION...MAINLY LATE SAT NGT AND MAINLY ACROSS NERN MO AND W
CNTRL IL...AS A STRENGTHENING SWLY LOW LEVEL JET BRINGS STRONG
LOW-MID LEVEL WAA TO THIS AREA ALONG WITH INCREASING LOW LEVEL
MOISTURE. THE CHANCE OF RAIN WILL CONTINUE ACROSS NERN MO AND W
CNTRL IL ON SUN AS AN UPPER LEVEL AND ASSOCIATED SFC LOW MOVE
NEWD THROUGH THE NRN PLAINS DRAGGING A COLD FRONT SLOWLY SEWD INTO
THE NWRN PORTION OF OUR FORECAST AREA. THIS FRONT SHOULD SAG SLOWLY
S-SEWD THROUGH OUR FORECAST AREA SUN NGT AND MON. THE GFS MODEL IS A
LITTLE MORE PROGESSIVE WITH THIS FRONT THAN THE ECMWF MODEL. IT
APPEARS THAT MOST OF THE PRECIPITATION WILL BE POST FRONTAL...BUT
WITH A LOT OF UNCERTAINTY WITH THE EXACT PLACEMENT OF THIS FRONT
WILL NEED TO BROADBRUSH CHANCE POPS ACROSS THE ENTIRE FORECAST
AREA MON NGT THROUGH TUE NGT. THE COOLEST TEMPERATURES SHOULD BE
ACROSS NERN MO WELL BEHIND THE COLD FRONT. THE BEST CHANCE OF RAIN
IS EXPECTED ON WED AND WED NGT AS A SFC LOW DEVELOPS ALONG THE
FRONT AS AN UPPER LEVEL TROUGH APPROACHES. THE ECMWF MODEL KEEPS
THE MAIN SFC LOW N OF OUR AREA MORE TYPICAL OF SPRING...WHILE THE
GFS MODEL IS FURTHER S WITH THE TRACK OF THE SFC LOW...KEEPING IT
JUST S OF OUR AREA AND IS A COLDER SOLUTION.
GKS
&&
.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 627 AM CDT THU APR 11 2013
CEILINGS ARE IFR/LOW MVFR ACROSS THE REGION THIS MORNING. EXPECT A
SLOW INCREASE IN CEILINGS THROUGH THE DAY BEFORE BECOMING VFR BY
THIS AFTERNOON. WESTERLY WINDS WILL BE IN THE 10-14KT RANGE WITH
SOME GUSTS TO AROUND 20KTS. THERE WILL BE SCATTERED -SHRA MOVE
ACROSS NORTHEAST MO/WEST CENTRAL ILLINOIS THIS AFTERNOON...BUT
COVERAGE WILL NOT BE ENOUGH TO INCLUDE IN THE KUIN AT THIS TIME.
SPECIFICS FOR KSTL...CEILINGS WILL BE IN THE 800-1200FT RANGE
THROUGH 15Z BEFORE SLOWLY INCREASING THROUGH THE DAY. WESTERLY
WINDS WILL BE IN THE 10-14KT RANGE WITH SOME GUSTS TO AROUND
20KTS.
BRITT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
221 PM EDT THU APR 11 2013
.SYNOPSIS...
UNSETTLED CONDITIONS WILL PREVAIL INTO SATURDAY AS A COMPLEX AREA
OF LOW PRESSURE MOVES FROM THE GREAT LAKES INTO THE NORTHEAST.
RAIN SHOWERS...POSSIBLY MIXED WITH SLEET OVER PORTIONS OF CENTRAL
NEW YORK...CAN BE EXPECTED INTO FRIDAY...THEN SCATTERED RAIN OR
SNOW SHOWERS PERSISTING INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE... WE`VE TIGHTENED UP THE POP/WX GRIDS FOR THE REST
OF THE DAY INTO THIS EVE...OTHWS NO SIG CHGS ATTM.
ON THE LARGE-SCALE...E-W ORIENTED BNDRY ACRS PA CONTS TO SINK
FURTHER S ATTM...AS EVIDENCED BY THE SWD ADVANCEMENT OF THE LWR
CLOUD MASS. IN THE MEANTIME...THE "WARM FRNT ALOFT (ARND 850 MB)"
IS SITUATED ACRS NY STATE...WITH THE STEADIER PCPN FOCUSED ALG AND
N OF THIS FEATURE. BASED ON RADAR COVERAGE UPSTREAM...AND THE
LIKELY PASSAGE OF ADDTNL UPR-LVL S/WVS...WE EXPECT STEADY...ALBEIT
FAIRLY LGT PCPN...TO CONTINUE UP N THROUGH THE DAY...AND RIGHT
INTO TNT. AS FAR AS PTYP IS CONCERNED...WE`VE HAD SOME OCNL SLEET
MIX WITH THE RAIN THIS AM ACRS SOME OF OUR FAR NRN AREAS...AND
THIS MAY ALSO PERSIST THIS AFTN. A LOOK AT THE 12Z ALY/BUF RAOBS
SHOWS A DISCERNIBLE SUB-FRZG LYR BETWEEN ABT 1500 AND 4000 FT AGL.
THERE`S ALSO PLENTY OF COLD DRY AIR JUST TO OUR N...CONTINUING TO
TRY TO FEED INTO THE RGN. FORTUNATELY...SFC TEMPS ARE GENERALLY
ABV FRZG...AND GIVEN TIME OF DAY AND YEAR...WE EXPECT THIS WILL
CONTINUE TO BE THE CASE THIS AFTN...MITIGATING ANY FZRA POTENTIAL.
FARTHER S...PCPN WILL BE MUCH LGTR AND MORE SPOTTY THROUGH THE SRN TIER
OF NY...WITH DRY WX BASICALLY FORESEEN ACRS NE PA/SULLIVAN NY.
TEMPS MAY GO UP A FEW MORE DEGS THROUGH EARLY AFTN...BUT WE DON`T
EXPECT MUCH CHG FROM PRESENT READINGS...WITH LOW-LVL CAA AT PLAY N
OF THE ABV MENTIONED SFC FRNT.
620 AM UPDATE... TD`S HAVE FALLEN INTO THE L/M30S ACRS THE FINGER
LAKES AND CNTRL SRN TIER...WITH M20S JUST S OF LAKE ONTARIO. POTNL
FOR SOME PL THIS MRNG AS BAND OF SHRA ENTERS THESE AREAS. SIG
DIFFS IN THE PROFILES FOR NRN ONEIDA W/RESPECT TO A MIX LATER TDA
AND TNGT BUT WITH LOW CONFIDENCE WILL LET DAY SHIFT TAKE A CLOSER
LOOK AT THE 12Z DATA. PREV BLO...
NOT MUCH CHG FROM PREV FCST. INITIAL LOOK AT MDL GUIDANCE
APPEARED TO SHOW A COOL BIAS AT F06 W/RESPECT TO T/TD`S. GROUND
TEMPS WILL BE RELATIVELY WARM...AND WE DON`T SEE SFC TEMPS OR SFC
WET BULBS GETTING BLO 32F THIS MRNG...REDUCING OR ELIMINATING ANY
FZRA THREAT. THIS HAS BEEN REFLECTED IN THE LATEST WWD GUIDANCE
WHICH LOOKS GOOD FROM OUR PERSPECTIVE. POPS INCRSNG FROM SW TO NE
AS NXT BATCH OF SHRA MOVS BACK INTO THE RGN. KEPT POTNL FOR SOME
SLEET TO MIX IN WITH THE RAIN ACRS PORTIONS OF THE CNTRL SRN TIER
AND FINGER LAKES...AND NRN ONEIDA.
FVRBL JET CONFIGURATION TNGT WITH FCST AREA IN RR QUAD OF THE 250
MB JET...COUPLED WITH A 50 KT SRLY 850 JET. GOOD ISEN LIFT TNGT
INTO FRI AHEAD OF THE OCCLUDED FNT. COOLEST AIR WILL RESIDE ACRS
ERN ZONES...BUT MDLS AGAIN MAY BE OVERDONE WITH THE LOW LVL COOL
AIR. RETAINED POTNL FOR SOME SLEET FROM NRN ONEIDA INTO THE WRN
CATSKILLS. COULD GET FAIRLY GUSTY TNGT...SPCLY HIGHER
ELEVATIONS...AS SELY FLOW INCRS.
WE`LL PRBLY SEE A GOOD 3/4 TO ONE INCH OF RAIN THU NGT INTO
FRI. WE SHOULD BE ABLE TO HANDLE THESE AMTS...BUT A FEW MAIN STEM
POINTS MAY APRCH CAUTION STAGE.
LASTLY...CAN`T RULE OUT ISOLD TSRA THIS AFTN OR TNGT...SPCLY ACRS
PA...BUT WILL JUST GO WITH SHRA FOR NOW AND LET LATER UPDATES ADD
MENTION IF NEEDED.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
OCCLUDED FNT PASSES ON FRI...WITH BATCH OF RAIN XPCTD TO MOV OUT
OF ERN ZONES FRI AFTN. MAIN UPR TROF REMAINS OVER THE
GTLAKES...AND S/WV`S EMBEDDED IN THE SWLY FLOW ACRS NY/PA COULD
TRIGGER SCT -SHRA...WITH POTNL FOR -SHSN LATER AT NGT. A WEAK WAVE
IS EXPECTED TO PASS FRI NGT...WITH A STRONGER S/WV ON SAT.
RETAINED CHC POPS MAINLY ACRS CNTRL NY AND NRN PA...WITH ONLY SLGT
CHC POPS FAR SE ZONES.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
2 PM UPDATE...
FOLLOWED WPC GUIDANCE. CONTINUATION OF THE WET AND UNSETTLED
CONDITIONS IN THE LONG TERM. UPPER TROF OVER NE US MOVES EAST
EARLY IN THE LONG TERM. A RIDGE OF HIGH PRESSURE WITH BRIEF DRY
AIR SUNDAY NIGHT INTO MONDAY BEFORE A SLOW MOVING COLD FRONT
BRINGS RAIN SHOWERS. MUCH LIKE THIS WEEK THE FRONT WAFFLES NORTH
AND SOUTH ACROSS THE AREA TUESDAY TO THURSDAY. LATE THURSDAY
MODELS BRING A STRONG COLD FRONT AND UPPER LEVEL TROF. MODELS
TIMING MAY BE TOO FAST WITH THE DEEP TROF IN THE WEST.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
130 PM UPDATE...
AVIATION FORECAST REMAINS DIFFICULT...DUE TO COMPLICATIONS OF
BATCHES OF SHOWERS MOVING ALONG A WAFFLING FRONTAL BOUNDARY IN
SOUTHERN PA THAT WILL LIFT NORTH THE REST OF TODAY FOLLOWED BY A
COLD FRONT FRIDAY.
MOSTLY VFR NOW...BUT CIGS WILL FALL TO MVFR LATE TODAY AND THIS
EVE THEN TO IFR CIG AND MVFR VSBYS LATE TONIGHT. THE IFR WILL
CONTINUE THROUGH 12Z AND MAYBE THROUGH 18Z. KAVP THE EXCEPTION AND
MVFR CIGS NOW WHICH SHOULD CONTINUE INTO THE EVENING.
A N TO NE 5 TO 10 KTS SHIFTING TO EAST TONIGHT AND INCREASING TO
10 TO 15 KTS WITH HIGHER GUSTS.
.OUTLOOK...
FRI AFTN...MVFR WITH PDS OF IFR AS SHOWERY FRONT PASSES. IMPROVING
TO VFR LATE.
FRI NGT TO SUN NGT...VFR...PSBL MVFR IN MIXED SHWRS.
MON TO TUE...MVFR IN RAIN.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM/MDP/TAC
NEAR TERM...MLJ
SHORT TERM...
LONG TERM...TAC
AVIATION...TAC
AREA FORECAST DISCUSSION
NWS GREENVILLE-SPARTANBURG SC
209 PM EDT THU APR 11 2013
.SYNOPSIS...
A STRONG COLD FRONT WILL CROSS THE WESTERN CAROLINAS AND NORTHEAST
GEORGIA TONIGHT. DRY HIGH PRESSURE WILL THEN BUILD IN FROM THE WEST
AND PERSIST THROUGH THE WEEKEND. AN UPPER LEVEL DISTURBANCE WILL
DEVELOP OVER THE GULF COAST SUNDAY AND BRING MOISTURE BACK ACROSS
THE REGION THROUGH THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
10 AM UPDATE...REEVALUATING TIMING OF CONVECTION THIS AFTN. 00Z EMC
4KM WRF DOING WELL WITH TIMING OF FRONTAL CONVECTION OVER THE LOWER
TENN AND MISS VALLEYS THIS MRNG. NO DEVELOPMENT YET IN THE WARM
SECTOR EITHER ON RADAR OR ON THE MODEL PROGS FOR THE CURRENT
TIME...BUT IT SHOWS SOME ACTIVITY DEVELOPING IN 16-17Z TIMEFRAME
OVER GA. NONETHELESS THIS WOULD NOT AFFECT ANY OF OUR ZONES UNTIL
AROUND 18Z. LATEST RAP KEEPS ACTIVITY OUT OF THE AREA UNTIL CLOSER
TO 20Z. SOME OTHER HI-RES MODELS DO DEVELOP SOME ISOLATED CONVECTION
PRIOR TO 18Z THOUGH. AS A RESULT I HAVE DELAYED/LOWERED POPS
SLIGHTLY THOUGH CONTINUING TO FOCUS ON THE SAVANNAH RIVER VALLEY FOR
MIDDAY DEVELOPMENT. SEE NO REASON TO THINK THAT SEVERE THREATS ARE
ANY DIFFERENT DESPITE PERHAPS GETTING A LATER START...GIVEN CONTINUED
GUIDANCE AGREEMENT ON ENVIRONMENTAL SHEAR AND DECENT INSTABILITY.
OTHERWISE...ADJUSTED SKY COVER FOR LATEST TRENDS AND SLOWED WARMING
UNTIL LOWER STRATUS MIX OUT LATE MRNG.
AS OF 345 AM...THROUGH THIS AFTERNOON...THE CWA WILL REMAIN BETWEEN
A STRONG COLD FRONT OVER THE MISSISSIPPI RIVER VALLEY AND HIGH
PRESSURE CENTERED OVER THE WESTERN ATLANTIC. THIS PATTERN WILL
PROVIDE ANOTHER DAY OF RETURN FLOW ACROSS THE REGION. MARGINALLY
GUSTY SW WINDS ARE EXPECTED TO DEVELOP AROUND MID DAY AND REMAIN
INTO TONIGHT. RECENT SATELLITE IMAGES INDICATED A SHIELD OF FAIRLY
THICK DEBRIS CIRRUS...MOVING WEST TO EAST. IN ADDITION...A FEW BANDS
OF STRATUS MAY DEVELOP ACROSS PORTIONS OF THE PIEDMONT THIS MORNING.
AS THE H5 RIDGE BUILDS OVER THE WESTERN ATLANTIC...HEIGHTS ACROSS
THE CWA WILL DECREASE. LLVL THICKNESSES AND H85 TEMPERATURES WILL
COOL A CATE OR TWO FROM YESTERDAY. THE COMBINATION OF INCREASING SKY
COVER AND SLIGHTLY COOLER LLVL TEMPS SHOULD RESULT IN HIGH TEMPS
AROUND 5 DEGREES LOWER THAN OBSERVED YESTERDAY...OR 5 DEGREES WARMER
THAN NORMAL. HIGHS IN THE U70S TO NEAR 80 WILL COMBINE WITH SFC
DEWPOINTS IN THE L60S TO SUPPORT A BROAD FIELD OF WEAK INSTABILITY
BY MID AFTERNOON. THE INSTABILITY SHOULD SUPPORT A HEALTHY FIELD OF
CU...HOWEVER...LINGERING WARM TEMPS AROUND H65 SHOULD WEAKLY CAP
DEEP CONVECTION FROM MORNING THROUGH MID AFTERNOON.
CONDITIONS WILL BECOME MORE SUITABLE FOR DEEP CONVECTION ACROSS THE
UPPER SAVANNAH VALLEY AND PORTIONS OF THE UPSTATE DURING THE LATE
AFTERNOON HOURS. MID LEVEL HEIGHTS ARE EXPECTED TO STEADILY DECREASE
AS AN INCREASINGLY NEGATIVELY TILTED TROF PUSH ACROSS THE DEEP
SOUTH. AS THE HEIGHTS DECREASE...THE WEAK AFTERNOON H85 INVERSION
ERODES...EASING CONVECTION TO DEEPEN WITHIN A LAYER OF CAPE AROUND
1000 J/KG. IN ADDITION...THE NEGATIVELY TILTED H5-H7 TROF WILL
RESULT IN THE LLVL WINDS TO BACK. IT IS DURING THIS PERIOD OF BACK
WIND FIELDS...FROM 23Z THROUGH 5Z...THAT NE GA AND SC 0-1KM HELICITY
RANGES FROM 150 TO 250...WITH SHEAR BETWEEN 20 TO 25 M/S. SWEAT
VALUES EXCEED 300 DURING THE MID EVENING HOURS. FORECAST SOUNDINGS
INDICATE THAT SIMILAR KINEMATICS SPREAD ACROSS THE CLT METRO AREA
BETWEEN MIDNIGHT INTO 4 AM. IN FACT...THE NAM HODOGRAPHS OVER CLT
APPEARS MORE TURNED...AS BL WINDS BECOME SE.
IT IS INTERESTING TO EVALUATE THE CONVECTIVE MODE IN THE CONVECTION
ALLOWING HIGH RES MODELS. EACH SOLUTION APPEARS TO SUPPORT TWO
ROUNDS OF SIGNIFICANT CONVECTION. THE FIRST ROUND DEVELOPS WELL
AHEAD OF THE FRONTAL BAND...WITH A CLUSTER FAVORED TO INITIALIZE
ACROSS THE CENTRAL SAVANNAH RIVER VALLEY AFTER 19Z. THIS CONVECTION
APPEARS TO ORGANIZED IN A NW TO SE ORIENTED BOW...SURGING NE ACROSS
THE UPSTATE. THE SECOND ROUND IS CLOSELY ASSOCIATED WITH THE SFC
COLD FRONT. THIS ACTIVITY APPEARS TO STAY INTACT AS IT CROSS THE NE
GA AND THE WESTERN CAROLINAS. GIVEN THE AMOUNT OF
HELICITY...SHEAR...AND CAPES NEAR 1000 J/KG...THE CONVECTIVE MODE
APPEARS LESS LINEAR THAN WHEN THE FRONT WAS FURTHER WEST.
INSTEAD...SIMULATED REFLECTIVITY SUGGESTS THAT CONVECTION WILL
ARRIVE WITH THE SECOND ROUND AS A COMBINATION OF SUPERCELLS AND
SHORT LINE SEGMENTS. WE WILL CONTINUE TO HIGHLIGHT THE THREAT OF
DAMAGING WINDS AND POSSIBLY OF A TORNADO OR TWO IN THE HWO. IN
ADDITION...SEVERE HAIL MAY EXIST WITH THE SUPERCELLS.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
AS OF 115 PM THURSDAY...A RATHER STRAIGHTFORWARD SYNOPTIC PATTERN
DEVELOPS THROUGH THE SHORT TERM. THE MODELS AGREE WELL WITH HEIGHTS
RISING AND THE H5 FLOW TRANSITIONING FROM BROADLY CYCLONIC TO
ANTICYCLONIC THROUGH 00Z MON. THERE WILL BE NO GOOD CHANCE OF PRECIP
THROUGH THE PERIOD AS DEEP LAYERED DRYING MOVES IN FROM THE NW AND
PERSISTS UNTIL UPPER/MID CLOUDS DEVELOP OUT OF THE SW BY MID DAY
SUN. SLIGHT POPS WERE MAINTAINED VERY LATE AROUND 21Z SUN AS
ISENTROPIC LIFT DEVELOPS ALONG WITH INCREASING MOISTURE FLUX. A LOOK
AT BL THETA/E SHOWS FAIRLY WEAK CAA FRI NIGHT...HOWEVER VERY GOOD
INSOLATION AND A DOWNSLOPING COMPONENT WILL OFFSET THE COOLING AND
ALLOW MAX TEMPS A COUPLE DEGREES ABOVE NORMAL. WITH THE INCREASING
UPPER CLOUDS SUN...INSOLATION WILL BE LIMITED YET H100/H85
THICKNESSES INCREASE BY 25 M FROM SAT AFTERNOON VALUES...THUS STILL
EXPECT A CONTINUED INCREASE IN MAXIMUM TEMPS...ABOUT 4-5 DEGREES
ABOVE NORMAL. MIN TEMPS WILL BE RIGHT AROUND NORMAL WITH PERHAPS
ENOUGH COOLING ACROSS THE HIGHER NC MTN TERRAIN TO PRODUCE PATCHY OR
AREAS OF FROST.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
AS OF 200 PM THU...ALL MEDIUM RANGE MODELS CONTINUE TO FORECAST A
SOUTHERN STREAM WAVE TO MOVE ACROSS THE FORECAST AREA ON MONDAY.
ALSO...ALL THE MODELS SHOW SOME DEGREE OF QPF RESPONSE WITH THIS
FEATURE. THEREFORE...WILL CONTINUE WITH THE IDEA OF FEATURING
SCATTERED TYPE POPS BEGINING LATE SUNDAY NIGHT AND CONTINUING
THROUGH MONDAY. IT APPEARS THAT THE SOUTHERN PORTION OF THE AREA
MIGHT HAVE BETTER COVERAGE AND THIS WILL BE LIKELY BE REFINED WITH
LATER FORECASTS.
AFTER THE WAVE EXITS TO THE EAST MONDAY NIGHT...AN UPPER RIDGE IS
FORECAST TO DEVELOP OVER THE SE STATES AND LINGER THROUGH MIDWEEK. I
LIKE THE ECM DEPICTION OF THE SENSIBLE WEATHER IN THE TUE/WED
TIMEFRAME WHICH DEPICTS ESSENTIALLY DIURNAL TYPE SHOWERS/TSTORMS
WHICH FITS THE CONCEPTUAL MODEL OF THE EXPECTED WEATHER PATTERN.
HENCE WILL FORECAST SCATTERED AFTERNOON SHOWERS/TSTORMS...BUT KEEP
THEM CONFINED TO THE MOUNTAINS. ON THU...A COLD FRONT WILL APPROACH
FROM THE WEST AND PERHAPS MOVE THROUGH THE AREA BY LATE IN THE DAY
PER THE GFS. THE ECM IS SLOWER AND HPC HAS TAKEN A COMPROMISE
SOLUTION WHICH STILL RAMPS UP CHANCE POPS ACROSS THE AREA ON THU.
TEMPERATURES WILL BE NEAR SEASONAL LEVELS ON MONDAY AND THEN WARM TO
WELL ABOVE NORMAL ON TUE/WED AND THEN BACK TO NEAR NORMAL FOR THU
DUE TO CLOUDS AND PRECIP.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AT KCLT...TWO ROUNDS OF SHOWERS/THUNDERSTORMS EXPECTED TO AFFECT THE
FIELD DURING THE PERIOD. FIRST...MOIST SOUTHERLY FLOW IN WARM SECTOR
OF LOW PRESSURE SYSTEM OVER THE MIDWEST WILL ALLOW SFC BASED
CONVECTION LATE THIS AFTN IN THE AREA. INITIALLY THE ATMOSPHERE WILL
REMAIN CAPPED AND ONLY SHALLOW CU WILL BE POSSIBLE BUT THIS CAP WILL
ERODE WITH MIDLEVEL TROUGHING/COOLING LEADING TO CAPE VALUES UPWARDS
OF 500 J/KG. DEEP LAYER SHEAR IS SUFFICIENT FOR ANY RESULTING TSRA
TO PRODUCE DAMAGING WIND GUSTS...AND THIS IS THE MAIN REASON WHY THE
REGION IS INCLUDED IN SPC SLIGHT RISK. CIGS SHOULD STAY VFR WITH
AFTN CONVECTION THOUGH HEAVY RAIN MAY REDUCE VSBY TO MVFR.
CONVECTION WILL DIMINISH SOMEWHAT WITH SUNSET BUT REMAIN SUPPORTIVE
OF TSRA OVERNIGHT. ADDITIONAL ACTIVITY WILL MAINLY BE ASSOCIATED
WITH COLD FROPA PROVIDING STRONG FORCING LATE TONIGHT. SHEAR WILL BE
STRONGER AT THAT TIME...AND GIVEN THE FORCING STORMS ARE EXPECTED TO
BE ABLE TO ORGANIZE INTO A LINE WHICH COULD PRODUCE WIDESPREAD
DAMAGING WINDS. PER LATEST MESOSCALE MODEL RUNS THIS LINE SHOULD
AFFECT THE FIELD AROUND 09Z. SOME LIGHT SHOWERS OR BRIEF TS MAY
CONTINUE BEHIND THE FROPA THROUGH DAYBREAK AS WINDS BEGIN TO SHIFT
TO SW.
ELSEWHERE...GENERALLY SIMILAR TO KCLT. THE GREATEST INSTABILITY WILL
BE PRESENT OVER THE UPSTATE...PARTICULARLY WEST AND SOUTH OF KGSP.
THUNDER THIS AFTERNOON WILL BE CAPABLE OF AT DAMAGING WIND GUSTS AND
AT LEAST SMALL HAIL...WITH INSTABILITY BECOMING A LIMITING FACTOR BY
EVENING. VSBY IN THE THUNDERSTORMS COULD BE AS LOW AS 1SM THOUGH
THIS IS EXPECTED TO BE ISOLATED...WITH MVFR REASONABLY LIKELY AROUND
THE AREA. COLD FROPA WITH LINE OF POTENTIALLY SEVERE CONVECTION
EXPECTED TO ENTER THE SW MTNS AND NE GA AROUND 06Z THEN PUSH EAST OF
KCLT BY 12Z. SOME LLVL MOISTURE LINGERS BEHIND THE FRONT SO MVFR
CIGS SHOULD LAST INTO FRI MRNG.
OUTLOOK...DRY HIGH PRESSURE WILL BUILD BACK OVER THE REGION ON
FRIDAY AND REMAIN THROUGH THE WEEKEND.
CONFIDENCE TABLE...
18-24Z 00-06Z 06-12Z 12-18Z
KCLT HIGH 98% MED 61% MED 69% HIGH 85%
KGSP HIGH 83% MED 62% MED 74% MED 76%
KAVL HIGH 82% MED 71% MED 76% MED 76%
KHKY HIGH 100% MED 66% MED 77% MED 73%
KGMU HIGH 83% MED 70% MED 72% MED 75%
KAND HIGH 83% MED 68% MED 73% HIGH 80%
THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)
WWW.WEATHER.GOV/GSP/AVIATION_TABLES
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.
&&
$$
SYNOPSIS...SBK
NEAR TERM...NED/WIMBERLEY
SHORT TERM...SBK
LONG TERM...LG
AVIATION...WIMBERLEY
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
121 PM CDT THU APR 11 2013
.UPDATE...
18Z AVIATION DISCUSSION UPDATED BELOW.
LIGHT SNOW CONTINUES TO WRAP INTO THE REGION EARLY THIS AFTERNOON.
EXPECT THIS TO DIMINISH INTO THE LATE AFTERNOON AND EARLY EVENING
WITH ADDITIONAL ACCUMULATIONS OF AN INCH OR TWO. WINDS DONT SEEM
TO BE MUCH OF A PROBLEM ALONG WITH BLOWING SNOW. THUS...CANCELLED
THE WINTER STORM WARNING AND ADVISORY FOR THE EASTERN PART OF THE
REGION.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
LEFT EXIT REGION RESPONSIBLE FOR TRANSIENT BANDS OF MODERATE TO
HEAVY SNOWFALL THIS MORNING. HRRR DEPICTING CURRENT CONDITIONS
FAIRLY WELL...AND TRANSITIONS AREA OF HIGHEST RETURNS/BEST FORCING
NORTH OF THE CWA BY MID DAY. ASIDE FROM MINOR CONFIGURATION
CHANGES TO HEADLINES EARLIER...WILL STICK WITH CURRENT TIMING ON
END OF ACCUMULATING SNOWFALL. SREF PROBABILITIES STILL SUGGESTING
A FEW SPOTS TO TOP 8 INCHES IN FAR EASTERN SOUTH DAKOTA/MINNESOTA
COUNTIES.
WITH THE LAST OF THE SYNOPTIC SCALE SNOWFALL MOVING OUT...MODELS
STILL HINT AT A PERSISTENT STRATUS LAYER OVER THE REGION THROUGH
THE START OF THE WEEKEND. THE LACK OF THERMAL ADVECTION...AND H85
READINGS AROUND -7C OR A STANDARD DEVIATION BELOW CLIMO...SUGGEST
FORECAST TEMPERATURES THROUGH SATURDAY WILL REMAIN WELL BELOW
NORMAL. WE WILL SEE SOME DECENT THERMAL ADVECTION BETWEEN 1 TO 3KFT
LATE IN THE PERIOD OUT WEST...HOWEVER SOUTHEASTERLY LOW LEVEL FLOW
WILL CUT DOWN ON MIXING POTENTIAL AND INCREASING MID/HIGH CLOUDS
SHOULD LIMIT DAYTIME HEATING. THUS...HIGHS STILL SOME 10-15
DEGREES BELOW NORMAL THE HIGH POINT IN TEMPERATURES THIS PERIOD.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
A LOW PRESSURE SYSTEM WILL BE APPROACHING THE AREA FROM THE WEST
WHEN THE PERIOD STARTS. WAA PRECIPITATION ON THE LEADING EDGE OF
THE SYSTEM LOOKS PRETTY CERTAIN SATURDAY NIGHT...ESPECIALLY ACROSS
THE EASTERN CWA. THE SYSTEM SWINGS TO THE NORTHEAST ON SUNDAY AND
THERE LOOKS TO BE A BREAK IN THE PRECIPITATION SUNDAY NIGHT AND
MONDAY. ANOTHER SYSTEM THEN TRACKS ACROSS THE CENTRAL OR SOUTHERN
PLAINS DURING THE LATTER HALF OF THE PERIOD. THE GFS AND THE GEM
ARE CONSIDERABLY FURTHER SOUTH WITH THIS SYSTEM THAN THE
ECMWF...SO THERE IS A POSSIBILITY THAT WE WILL REMAIN DRY.
HOWEVER...AM NOT COMFORTABLE STRAYING THAT FAR FROM THE
ALLBLEND...SO WILL LEAVE A SMALL POP IN MONDAY NIGHT THROUGH
WEDNESDAY TO ACCOUNT FOR TRACKING DIFFERENCES.
WITH NEW SNOW COVER OVER MUCH OF THE CWA...DO NOT EXPECT TO SEE
TEMPERATURES REACH MEX GUIDANCE VALUES...AND WILL STAY ABOUT 5 TO
10 DEGREES BELOW IT FOR DAYTIME HIGHS. THIS WILL RESULT IN HIGH
TEMPERATURES MAINLY IN THE 30S AND 40S...WITH OVERNIGHT LOWS IN
THE 20S.
&&
.AVIATION...
18Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
AREAS OF -SN AND BR WILL PERSIST AT ALL TERMINALS THROUGH THE
AFTERNOON HOURS. VSBYS AT TIMES IN HEAVIER SNOW BANDS MAY DROP TO
AROUND 1SM OR LESS. CIGS WILL GENERALLY BE IFR/MVFR. THIS
EVENING...EXPECT -SN TO CONTINUE MAINLY AT KABR AND KATY WITH -SN
GRADUALLY ENDING BY MORNING. IFR/MVFR CIGS EXPECTED TO PERSIST
THROUGH FRIDAY MORNING.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&
$$
UPDATE...MOHR
SHORT TERM...CONNELLY
LONG TERM...PARKIN
AVIATION...TMT
WEATHER.GOV/ABERDEEN
AREA FORECAST DISCUSSION...UPDATED
NWS ABERDEEN SD
1054 AM CDT THU APR 11 2013
.UPDATE...
WRAPAROUND/TROWAL SNOW WILL CONTINUE THROUGH THE AFTERNOON AND
SLOWLY DIMINISH IN COVERAGE AND INTENSITY. ADJUSTED WX AND POP GRIDS
FOR THE DRYING/NO SNOW AREA SWEEPING INTO THE EASTERN CWA LATE
THIS MORNING. THIS AREA SHOULD FILL BACK IN THROUGH THE LATE
AFTERNOON AND EARLY EVENING AND THEN END. ADDITIONAL AMOUNTS OF 1
TO 3 INCHES ARE EXPECTED. READJUSTED SNOWFALL GRIDS AND INCREASED
TOTAL SNOWFALL AMOUNTS. NOT MUCH INCREASE IN TEMPERATURES THROUGH
THE AFTERNOON.
&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TODAY THROUGH SATURDAY
LEFT EXIT REGION RESPONSIBLE FOR TRANSIENT BANDS OF MODERATE TO
HEAVY SNOWFALL THIS MORNING. HRRR DEPICTING CURRENT CONDITIONS
FAIRLY WELL...AND TRANSITIONS AREA OF HIGHEST RETURNS/BEST FORCING
NORTH OF THE CWA BY MID DAY. ASIDE FROM MINOR CONFIGURATION
CHANGES TO HEADLINES EARLIER...WILL STICK WITH CURRENT TIMING ON
END OF ACCUMULATING SNOWFALL. SREF PROBABILITIES STILL SUGGESTING
A FEW SPOTS TO TOP 8 INCHES IN FAR EASTERN SOUTH DAKOTA/MINNESOTA
COUNTIES.
WITH THE LAST OF THE SYNOPTIC SCALE SNOWFALL MOVING OUT...MODELS
STILL HINT AT A PERSISTENT STRATUS LAYER OVER THE REGION THROUGH
THE START OF THE WEEKEND. THE LACK OF THERMAL ADVECTION...AND H85
READINGS AROUND -7C OR A STANDARD DEVIATION BELOW CLIMO...SUGGEST
FORECAST TEMPERATURES THROUGH SATURDAY WILL REMAIN WELL BELOW
NORMAL. WE WILL SEE SOME DECENT THERMAL ADVECTION BETWEEN 1 TO 3KFT
LATE IN THE PERIOD OUT WEST...HOWEVER SOUTHEASTERLY LOW LEVEL FLOW
WILL CUT DOWN ON MIXING POTENTIAL AND INCREASING MID/HIGH CLOUDS
SHOULD LIMIT DAYTIME HEATING. THUS...HIGHS STILL SOME 10-15
DEGREES BELOW NORMAL THE HIGH POINT IN TEMPERATURES THIS PERIOD.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
A LOW PRESSURE SYSTEM WILL BE APPROACHING THE AREA FROM THE WEST
WHEN THE PERIOD STARTS. WAA PRECIPITATION ON THE LEADING EDGE OF
THE SYSTEM LOOKS PRETTY CERTAIN SATURDAY NIGHT...ESPECIALLY ACROSS
THE EASTERN CWA. THE SYSTEM SWINGS TO THE NORTHEAST ON SUNDAY AND
THERE LOOKS TO BE A BREAK IN THE PRECIPITATION SUNDAY NIGHT AND
MONDAY. ANOTHER SYSTEM THEN TRACKS ACROSS THE CENTRAL OR SOUTHERN
PLAINS DURING THE LATTER HALF OF THE PERIOD. THE GFS AND THE GEM
ARE CONSIDERABLY FURTHER SOUTH WITH THIS SYSTEM THAN THE
ECMWF...SO THERE IS A POSSIBILITY THAT WE WILL REMAIN DRY.
HOWEVER...AM NOT COMFORTABLE STRAYING THAT FAR FROM THE
ALLBLEND...SO WILL LEAVE A SMALL POP IN MONDAY NIGHT THROUGH
WEDNESDAY TO ACCOUNT FOR TRACKING DIFFERENCES.
WITH NEW SNOW COVER OVER MUCH OF THE CWA...DO NOT EXPECT TO SEE
TEMPERATURES REACH MEX GUIDANCE VALUES...AND WILL STAY ABOUT 5 TO
10 DEGREES BELOW IT FOR DAYTIME HIGHS. THIS WILL RESULT IN HIGH
TEMPERATURES MAINLY IN THE 30S AND 40S...WITH OVERNIGHT LOWS IN
THE 20S.
&&
.AVIATION...
12Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS
THE TAF FOR KATY REMAINS NIL DUE TO THE ASOS EQUIPMENT BEING NON
FUNCTIONAL.
AN AREA OF SNOW WILL REMAIN OVER THE EASTERN CWA DURING THE
MORNING HOURS. MVFR CIGS AND VSBYS WILL OCCASIONALLY BECOME IFR
UNDER THE HEAVIER SNOW BANDS. THE SNOW WILL TAPER OFF AND COME TO
AN END BY THIS EVENING...BUT CIGS WILL BECOME IFR AND REMAIN THAT
WAY THROUGH THE OVERNIGHT HOURS.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR BROWN-CLARK-
CODINGTON-DAY-DEUEL-GRANT-HAMLIN-MARSHALL-ROBERTS-SPINK.
WINTER WEATHER ADVISORY UNTIL 4 PM CDT THIS AFTERNOON FOR
EDMUNDS-FAULK-MCPHERSON.
MN...WINTER STORM WARNING UNTIL 7 PM CDT THIS EVENING FOR BIG STONE-
TRAVERSE.
&&
$$
UPDATE...MOHR
SHORT TERM...CONNELLY
LONG TERM...PARKIN
AVIATION...PARKIN
WEATHER.GOV/ABERDEEN