Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/03/12
AREA FORECAST DISCUSSION
NWS SAN JOAQUIN VALLEY - HANFORD CA
150 PM PST WED FEB 1 2012
.SYNOPSIS...WEAK UPPER LEVEL DISTURBANCES WILL CONTINUE TO MOVE
OVER THE FORECAST AREA THIS WEEK PRODUCING INTERMITTENT SCATTERED
MIDDLE AND HIGH CLOUDS BUT LITTLE IF ANY PRECIPITATION. VALLEY FOG
REMAINS A POSSIBILITY DURING THE NIGHTS AND MORNINGS.
&&
.DISCUSSION...COOL AND DRY UPPER NORTHERLY FLOW PREVAILING OVER
CENTRAL CA AT THIS TIME AS OUR AREA REMAINS SITUATED IN BETWEEN A
DEPARTED UPPER TROUGH OVER THE GREAT BASIN AND AN OFFSHORE RIDGE.
THE RIDGE IS PROGGED BY THE 12Z WRF AND GFS TO AMPLIFY OFF THE CA
COAST TONIGHT THEN BUILD INLAND ON THURSDAY. ONSHORE P-GRADS HAVE
STRENGTHENED WITH KSFO-KLAS AT 10.4 MB AND KBFL-KNID AT 6.7 MB AT
NOON TODAY. HI RESOLUTION RUC INDICATING P-GRADS WILL MAX OUT
LATER THIS AFTERNOON THEN WEAKEN RAPIDLY THIS EVENING. THE
INCREASED SURFACE GRADIENTS WILL RESULT IN A PERIOD OF BREEZY
CONDITIONS ACORSS THE KERN COUNTY MOUNTAINS AND DESERTS THROUGH
EARLY THIS EVENING...BUT DO NOT EXPECT WINDS TO REACH WIDESPREAD
ADVISORY CRITERIA. IN THE MEANTIME...SOME UPSLOPE STRATO-CUMULUS
HAS FORMED OVER THE SOUTHERN SIERRA FOOTHILLS WHILE SOME
INSTABILITY CUMULUS HAS PUSHED SOUTHWARD INTO MERCED COUNTY.
EXPECT THESE CLOUDS TO DISSIPATE TONIGHT AS CAA CONTINUES TONIGHT
AND MIXES OUT THE ATMOSPHERE. THE NORTHERLY FLOW PATTERN WILL ALSO
INHIBIT THE DEVELOPMENT OF WIDESPREAD FOG IN THE SAN JOAQUIN
VALLEY TONIGHT...BUT THERE IS ENOUGH RESIDUAL LOW LEVEL MOISTURE
NEAR THE VALLEY FLOOR SO SOME PATCHY FOG IS NOT OUT OF THE
QUESTION FOR TONIGHT.
MODEL CONSENSUS INDICATES THE RIDGE WILL KEEP DRY CONDITIONS OVER
OUR AREA THURSDAY THROUGH THE UPCOMING WEEKEND. TEMPERATURES WILL
RISE TO ABOVE SEASONAL NORMALS AS THE RIDGE STRENGTHENS OVER THE
AREA FRIDAY THROUGH THE WEEKEND. THE ONLY FORECAST PROBLEM FOR
THIS PERIOD WILL BE THE THE EXTENT OF ANY NIGHT AND MORNING FOG
IN THE SAN JOAQUIN VALLEY AND SUBSEQUENT IMPACT IT MAY HAVE ON
TEMPERATURES. THE INCREASING SUN ANGLE WILL LIKELY ALLOW FOR ANY
FOG THAT DOES FOR TO COMPLETELY BURN OFF BY LATE MORNING EACH
DAY...THAT IS UNLESS THE RIDGE COMPLETELY SQUISHES OUT ANY LOW
LEVEL MOISTURE.
THE 12Z GFS AND ECMWF BOTH INDICATE THE RIDGE WILL BREAK DOWN ON
MONDAY AND A SPLIT TROUGH WILL REACH THE CA COAST BY TUESDAY.
THE ECMWF IS SOMEWHAT MORE ROBUST WITH THE SPLITTING AND JUST
BRINGING A DEFORMATION BAND OF MID/UPPER LEVEL MOISTURE THROUGH
OUR AREA WHILE THE GFS HOLDS MORE OF IT TOGETHER AND BRING SOME
DEEPER MOISTURE INTO OUR AREA WHILE IT MOVES THROUGH CA ON TUESDAY
AND TUESDAY NIGHT. HAVE DECIDED TO COMPROMISE BETWEEN THE TWO
SOLUTIONS AND KEEP MENTION OF A SLIGHT CHANCE TO LOW CHANCE OF
RAIN AND MOUNTAIN SNOW FOR FRESNO COUNTY NORTHWARD TUESDAY AND
TUESDAY NIGHT TAPERING TO MOUNTAIN SHOWERS ON WEDNESDAY. ENSEMBLE
MEMBER AGREEMENT IS POOR SO DO NOT HAVE A LOT OF CONFIDENCE IN
DAYS 6 AND 7 AT THIS TIME.
&&
.AVIATION...IN THE SAN JOAQUIN VALLEY...LOCAL IFR/LIFR
VISIBILITIES CAN BE EXPECTED BETWEEN 09Z AND 18Z THURSDAY.
OTHERWISE...AREAS OF MVFR IN HAZE CAN BE EXPECTED THROUGH 00Z
FRIDAY. LOCAL MVFR CONDITIONS IN THE LOWER SLOPES OF THE SOUTHERN
SIERRA NEVADA THROUGH 04Z THURSDAY. OTHERWISE VFR CONDITIONS WILL
PREVAIL ACROSS THE CENTRAL CALIFORNIA INTERIOR THROUGH 00Z FRIDAY.
&&
.AIR QUALITY ISSUES...ON WEDNESDAY FEBRUARY 1 2012... UNHEALTHY
FOR SENSITIVE GROUPS IN KERN AND TULARE COUNTIES. FIREPLACE/WOOD
STOVE BURNING IS PROHIBITED IN FRESNO... KERN... KINGS AND TULARE
COUNTIES. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG
&&
.HNX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
PUBLIC...DS
AVN/FW...BEAN
SYNOPSIS...WP
WEATHER.GOV/HANFORD
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
444 AM EST WED FEB 1 2012
.SYNOPSIS...
LOW PRESSURE MOVING EASTWARD THROUGH SOUTHERN CANADA AND INTO
NORTHERN NEW ENGLAND TODAY WILL BRING A COLD FRONT THROUGH OUR AREA
THIS AFTERNOON...WHICH WILL STALL TO OUR SOUTH TONIGHT. ANOTHER WAVE
OF LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS
JUST SOUTH OF OUR AREA THURSDAY MORNING. HIGH PRESSURE WILL THEN
RETURN FOR LATER THURSDAY INTO SATURDAY. ANOTHER AREA OF LOW
PRESSURE MIGHT RIDE JUST SOUTH OF OUR REGION LATER SATURDAY NIGHT
INTO SUNDAY...OTHERWISE HIGH PRESSURE IS EXPECTED TO BUILD INTO
MONDAY. ANOTHER FRONT MAY AFFECT OUR REGION MONDAY NIGHT INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN FORECAST PROBLEM FOR TODAY WILL BE THE TIMING AND EXTENT OF
SHOWERS...MAINLY THIS MORNING.
THE AREA OF SHOWERS HAS EXPANDED AND SPED UP A BIT...AS THE LOW
LEVEL JET GETS CLOSER. PRECIPITABLE WATER VALUES HAVE INCREASED TO
NEAR 0.80 INCHES...AND THE AREA OF SHOWERS SITS RIGHT IN THE
RIDGING OF PRECIPITABLE WATER AND LOW LEVEL THETA E. THE FORECAST
WAS UPDATED TO EXPAND THE COVERAGE AND SPEED UP THE MENTION OF THE
TIMING OF THE BEST CHANCE OF SHOWERS.
SHOWERS HAVE ALSO INCREASED ACROSS SOUTHERN AREAS...AND THE
FORECAST WAS UPDATED FOR THIS AS WELL. SOME OF THE SHOWERS ACROSS
THE SOUTH HAVE CONVECTIVE LOOKS TO THEM...BUT THE AIRMASS IS
FAIRLY STABLE...AS DEW POINTS ARE STILL IN THE 30S.
THERE IS A SMALL CONCERN FOR GUSTY WINDS WITH THE PASSAGE OF THE
SHOWERS THIS MORNING. A PEAK GUST OF 39 KNOTS WAS NOTED AT KJST
BEFORE 0700 UTC...IN THE VICINITY OF SOME OF THE SHOWERS. THIS
APPEARS TO BE CLOSE TO THE NOSE OF THE 45 KNOT LOW LEVEL...AND THE
CONVECTIVE NATURE OF THE SHOWERS COULD BE HELPING TO MIX MOMENTUM
DOWN. FOR NOW...WILL CONTINUE TO MONITOR THE TRENDS IN GUSTS ACROSS
CENTRAL PENNSYLVANIA...AND ADD STRONGER WIND GUSTS TO THE FORECAST
AS NEEDED.
NEAR AND SHORT TERM MODELS PLACE THE AREA OF SHOWERS MAINLY
NORTHEAST OF THE AREA LATE THIS MORNING. AN ATTEMPT TO PLACE THE
BEST CHANCE OF SHOWERS WAS MADE BASED ON THE POSITION OF THE LOW
LEVEL JET AND THE SURFACE TROUGH. .
THE PASSAGE OF THE TROUGH (OR PERHAPS WEAK COLD FRONT) WILL ALLOW
THE DEPTH OF THE MIXED LAYER TO INCREASE. THE INCREASED MIXED LAYER
WILL ALLOW ACCESS TO 25 TO 30 KNOTS OF WIND IN THE WAKE OF THE
TROUGH...AND FOR A FEW HOURS AFTER. THIS SHOULD RESULT IN WEST WINDS
GUSTING TO 25 MPH FOR A TIME THIS AFTERNOON IN JUST ABOUT ALL AREAS.
SKIES SHOULD BECOME PARTLY SUNNY AFTER THE SURFACE TROUGH PASSAGE
(SOUTHERNMOST AREAS MAY BE PARTLY SUNNY THE ENTIRE TIME) AS MIXING
ALLOWS DRIER AIR FROM ABOVE TO BREAK THE LOWER CLOUDS. THE MID DECK
MAY TAKE THE BALANCE OF THE AFTERNOON TO CLEAR THE AREA. THIS IS
MENTIONED BECAUSE OF THE EFFECT ON TEMPERATURES. THE AIRMASS IS EVEN
WARMER AHEAD OF THE TROUGH EARLY THIS MORNING THEN IS WAS MONDAY
AFTERNOON.
WITH ALL THINGS BEING EQUAL...THIS WOULD RESULT IN HIGHER MAXIMUM
TEMPERATURES TODAY. HOWEVER...CLOUD COVER WILL BE A BIG ISSUE. MOST
OF THE REAL WARMING MAY HAVE TO WAIT UNTIL AFTER THE WINDS SHIFT AND
BETTER MIXING CAN OCCUR. THIS MEANS THAT HIGHS MAY NOT GET QUITE AS
HIGH AS THE HIGHER GFS MOS NUMBER SUGGEST. FOR NOW...A BLEND OF MOS
NUMBERS WAS USED FOR HIGHS TODAY...AND THIS COULD BE TWEAKED LATER
THIS MORNING IF THE CLOUD COVER IS NOT AS EXTENSIVE AS IT LOOKS LIKE
IT WILL BE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE SURFACE FRONT/TROUGH WILL STALL SOUTH OF THE AREA THIS EVENING.
WHILE THERE IS SOME MODEL SPREAD ON JUST HOW FAR SOUTH THE FRONT
GETS...ALL SHORT RANGE MODELS DEVELOP A SURFACE LOW ON THE FRONT. AT
THIS POINT...THE POSITION OF THE SURFACE LOW DOES NOT LOOK AS
IMPORTANT AS THE POSITION OF THE MID LEVEL FORCING FOR RAIN TONIGHT.
ALL SHORT RANGE MODELS SHOW AN AREA OF 700-500 MB FRONTOGENETIC
FORCING DEVELOPING AHEAD OF THE SHORT RANGE APPROACHING FROM THE
WEST. MOST PLACE THE BEST MID LEVEL FORCING ACROSS NORTHEAST
MARYLAND...MUCH OF DELAWARE...AS WELL AS SOUTHERNMOST NEW JERSEY.
THIS PLACEMENT HAS BEEN MORE OR LESS CONSISTENT OVER THE PAST 24
HOURS OR SO...AND WAS USED AS THE BASIS FOR THE BEST CHANCE OF RAIN
LATER TONIGHT.
THE AIRMASS ACROSS SOUTHERN AREAS DOES NOT GET A CHANCE TO DRY OUT
AS CENTRAL AND NORTHERN AREAS DO. THERE COULD BE SOME INITIAL LIGHT
RAIN ACROSS SOUTHERNMOST AREAS BEFORE MIDNIGHT...BUT MOST OF THE
STEADY LIGHT RAIN SHOULD OCCUR WITH THE DEVELOPMENT AND MOVEMENT OF
THE BEST MID LEVEL FORCING. THE BEST MID LEVEL LIFT SHOULD OCCUR
BETWEEN 0600 UTC AND 1200 UTC THURSDAY...WITH THE EMPHASIS LATER IN
THE PERIOD.
AGAIN...WHILE THERE IS SOME DIFFERENCE IN THE PLACEMENT OF THE
NORTHERN EDGE OF THE PRECIPITATION WITH THIS EVENT...IT WOULD APPEAR
THAT MOST PLACES SOUTH OF A KTHV-KILG-KACY SHOULD REMAIN DRY THROUGH
1200 UTC THURSDAY. THERE COULD BE SOME PLAY IN THE POSITION OF THIS
LINE...AND A SLIGHT CHANCE OF RAIN WILL BE FORECAST NORTH OF IT TO
INDICATE SOME REMAINING UNCERTAINTY.
MUCH OF THE REST OF THE AREA SHOULD REMAIN DRY...WITH VARYING CLOUD
HEIGHTS OVERNIGHT. CLEARING ACROSS THE NORTH SHOULD BE REPLACED BY
HIGH ALTOSTRATUS...AND CENTRAL AREAS COULD SEE THE MID CLOUDS LOWER
TOWARD DAYBREAK. IN ANY EVENT...THE MOS BLEND LOOKS OK FOR LOWS
TONIGHT...AND THERE WAS A LEAN TOWARD THE HIGHER NAM MOS NUMBERS DUE
TO THE CLOUDS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODEL GUIDANCE DOES NOT ENGENDER MUCH IN THE WAY OF CONFIDENCE AS
SOLUTIONS SEEM TO VARY AT LEAST SOMEWHAT FROM RUN TO RUN...AS WELL
AS MODEL TO MODEL FOR THE LATTER TIME PERIODS. AN INITIAL ZONAL FLOW
ALOFT FOR MUCH OF THE COUNTRY LOOKS TO SEGUE INTO SOMEWHAT OF A
BLOCKING REGIME LATER FRIDAY AND OVER THE WEEKEND...THEN RETURN TO
MORE OF A ZONAL CONFIGURATION EARLY NEXT WEEK. FOR OUR AREA, IT
APPEARS THAT WE WILL HAVE SEVERAL UPPER TROUGH PASSAGES IN A HIGH
SPEED UPPER FLOW PATTERN. HOW THIS TRANSLATES TO SENSIBLE WEATHER
FOR OUR AREA REMAINS PROBLEMATICAL. AT THE SURFACE, THE 00Z GFS
TRANSITS A WAVE ALONG THE STALLED BOUNDARY TO OUR SOUTH THURSDAY,
MAINLY IN THE MORNING, FOLLOWED BY A PERIOD OF HIGH PRESSURE INTO
SATURDAY. THEN, THE GFS RESOLVES ANOTHER WAVE PASSING TO OUR SOUTH
SATURDAY NIGHT INTO SUNDAY. THIS LOW IS EJECTED FROM A CLOSED UPPER
LOW OVER THE MID MISSISSIPPI VALLEY, BUT THEN IS CAPTURED BY A
DEVELOPING UPPER TROUGH MOVING SOUTHEASTWARD FROM THE EASTERN GREAT
LAKES BY SUNDAY. THE 00Z ECMWF DECLINES TO PASS THE SURFACE LOW EAST
OF ITS MIDWEST UPPER CLOSED LOW...INSTEAD BUILDING HIGH PRESSURE FOR
US FOR THE WEEKEND AND BRINGING A FRONT INTO THE AREA FOR MONDAY
NIGHT INTO EARLY TUESDAY. WITH DIFFERENT FORECASTS, IT WAS DECIDED
JUST TO INTRODUCE SLIGHT CHANCE PROBABILITIES TO OUR FAR SOUTHERN
ZONES SATURDAY NIGHT. THICKNESS CONSIDERATIONS DICTATED THAT A MIX
OF RAIN OR SNOW SHOWERS BE USED ON THE NORTHERN FRINGE OF THIS LOW
CHANCE EVENT. THIS WILL CARRY INTO THE INHERITED CHANCE
PROBABILITIES FOR SUNDAY AND INTO MONDAY. IT MAY TURN OUT THAT THE
LOW CHANCE PROBABILITIES FOR LATER SUNDAY INTO MONDAY ARE OVERDONE,
BUT FOR NOW CONTINUITY WAS USED. THEN, ONLY A SLIGHT CHANCE WAS
INTRODUCED FOR MONDAY NIGHT AND TUESDAY FOR CENTRAL AND NORTHERN
ZONES WITH THE INDICATED FRONTAL PASSAGE ON THE ECMWF.
ALTHOUGH TEMPERATURES MAY DIP AND RECOVER SLIGHTLY THROUGH THE
PERIOD, THEY ARE EXPECTED TO REMAIN ABOVE NORMAL THROUGH NEXT
TUESDAY AS COLD AIR REMAINS UNABLE TO PENETRATE SOUTHWARD TO OUR
LATITUDE.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A WAVE OF LOW PRESSURE PASSING TO OUR SOUTH THURSDAY...MAINLY IN THE
MORNING...SHOULD HAVE LITTLE EFFECT FOR OUR TAF SITES. ANOTHER WAVE
MAY PASS TO OUR SOUTH SATURDAY NIGHT INTO SUNDAY...BUT EVEN IF THAT
MATERIALIZED IT SHOULD HAVE MINIMAL IMPACT AS WELL. SO, VFR
CONDITIONS ARE EXPECTED THURSDAY AND RIGHT THROUGH THE OUTLOOK
PERIOD. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
THE APPROACHING LOW LEVEL JET IS DROPPING ENOUGH LOW LEVEL MOMENTUM
AT THE HIGHER PLATFORMS ON THE DELAWARE BAY FOR GUSTS AT OR ABOVE 25
KNOTS. SINCE THE LOW LEVEL JET WILL TAKE MOST OF THE MORNING TO
CLEAR THE REGION...A SMALL CRAFT ADVISORY WAS ISSUED FOR THE
DELAWARE BAY. THIS IS IN ADDITION TO THE SMALL CRAFT ADVISORY THAT
WAS IN PLACE FOR THE OCEAN WATERS...DUE MAINLY TO THE LOW LEVEL JET.
THE SURFACE GRADIENT EARLY THIS MORNING LOOKS AS THOUGH IT CAN
SUPPORT SMALL CRAFT WIND GUSTS ON THE OCEAN...AND THE GRADIENT
SHOULD REMAIN IN PLACE AHEAD OF THE SURFACE TROUGH. MODEL SOUNDINGS
DO NOT SHOW THAT MUCH MOMENTUM TRANSFER (NOT UNUSUAL DURING STRONG
WARM AIR ADVECTION SCENARIOS)...SO THE SMALL CRAFT WINDS PROBABLY
OCCUR MOSTLY BEFORE 1500 UTC. THE SAME IS TRUE ON DELAWARE
BAY...WHERE THE STRONGEST WINDS PROBABLY OCCUR NEARSHORE AND ACROSS
THE MOUTH OF THE BAY.
IN ADDITION...THE SOUTHWEST WIND IS CREATING A SWELL...WHICH
COMBINED WITH THE LOCAL WIND WAVE IS NEAR 5 FEET. THIS PROBABLY
PERSISTS THROUGH THE SURFACE TROUGH PASSAGE...AND PERHAPS A FEW
HOURS AFTER...AS THE SWELL SORTS ITSELF OUT. BASED ON THE
ABOVE...THERE IS NO CHANGE TO THE TIMING OF THE SMALL CRAFT ADVISORY
THROUGH EARLY AFTERNOON.
MODEL SOUNDINGS SHOW SOME MOMENTUM TRANSFER THIS AFTERNOON AS THE
GRADIENT INCREASES AND SLIGHTLY COOLER AIR STREAMS OUT OVER THE
WATERS. RIGHT NOW...THE GRADIENT DOES NOT APPEAR TO SUPPORT SMALL
CRAFT WINDS...AND GUSTS OF THAT MAGNITUDE COULD BE CONFINED TO THE
IMMEDIATE COAST. LATER FORECASTS MAY HAVE TO ACCOUNT FOR THIS AFTER
THE TROUGH PASSES.
THE BEST MOMENTUM ENDS THIS EVENING...AND WINDS AND SEAS WILL DROP
BELOW SMALL CRAFT LEVELS. A SURFACE LOW DEVELOPING ON THE PASSING
SURFACE TROUGH/FRONT SHOULD STILL BE IN THE INCIPIENT STAGE LATER
TONIGHT AS IT APPROACHES THE NORTH CAROLINA/VIRGINIA BORDER. WINDS
WILL SHIFT TO THE NORTH AND NORTHEAST IN RESPONSE TO THE SURFACE LOW
DEVELOPMENT...BUT RIGHT NOW IT APPEARS AS THOUGH WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS THROUGH 1200 UTC THURSDAY.
A WAVE PASSING JUST SOUTH OF OUR AREA THURSDAY MORNING WILL CAUSE
THE GRADIENT TO TIGHTEN UP...PROBABLY ENOUGH TO INDUCE SMALL CRAFT
ADVISORY LEVEL WINDS. SEAS WILL LIKELY RESPOND AS WELL, BUT THEY ARE
NOT EXPECTED TO RISE ABOVE 4 FEET AT THIS TIME. HIGH PRESSURE WILL
BUILD ACROSS OUR REGION LATER THURSDAY AND REMAIN INTO SATURDAY.
ANOTHER WAVE OF LOW PRESSURE MIGHT PASS JUST TO OUR SOUTH SATURDAY
NIGHT INTO SUNDAY. IF IT DOES, IT COULD INTENSIFY AS IT MOVES OUT
INTO THE WESTERN ATLANTIC...AND THIS MAY RESULT IN MORE SMALL
CRAFT ADVISORY CONDITIONS, BUT FOR NOW LOW CONFIDENCE EXISTS ON
THAT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ430-
431-450>455.
&&
$$
SYNOPSIS...
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...
AVIATION...HAYES
MARINE...HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
302 AM EST WED FEB 1 2012
.SYNOPSIS...
LOW PRESSURE MOVING EASTWARD THROUGH SOUTHERN CANADA AND INTO
NORTHERN NEW ENGLAND TODAY WILL BRING A COLD FRONT THROUGH OUR AREA
THIS AFTERNOON...WHICH WILL STALL TO OUR SOUTH TONIGHT. ANOTHER WAVE
OF LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS
JUST SOUTH OF OUR AREA THURSDAY MORNING. HIGH PRESSURE WILL THEN
RETURN FOR LATER THURSDAY INTO SATURDAY. ANOTHER AREA OF LOW
PRESSURE MIGHT RIDE JUST SOUTH OF OUR REGION LATER SATURDAY NIGHT
INTO SUNDAY...OTHERWISE HIGH PRESSURE IS EXPECTED TO BUILD INTO
MONDAY. ANOTHER FRONT MAY AFFECT OUR REGION MONDAY NIGHT INTO
TUESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE MAIN FORECAST PROBLEM FOR TODAY WILL BE THE TIMING AND EXTENT OF
SHOWERS...MAINLY THIS MORNING.
AN AREA OF SHOWERS CONTINUES TO EXPAND TO THE WEST ACROSS WEST
CENTRAL PENNSYLVANIA EARLY THIS MORNING. THE AREA OF SHOWERS IS
COINCIDENT WITH THE POSITION OF THE LOW LEVEL JET (NEAR 45 KNOTS AT
925 MB BASED ON THE 0000 UTC UPPER AIR ANALYSIS). THE SHOWERS ARE
FORMING ON WHAT APPEARS TO BE A SURFACE TROUGH...WITH NOT MUCH
THERMAL CONTRAST ALONG IT. AS THE LOW LEVEL JET STREAMS MOISTURE
ALONG THE TROUGH...THE SHOWER ACTIVITY SHOULD MAINTAIN ITSELF AS IT
REACHES THE LEHIGH VALLEY BEFORE 400 AM.
THERE IS A SMALL CONCERN FOR GUSTY WINDS WITH THE PASSAGE OF THE
SHOWERS THIS MORNING. A PEAK GUST OF 39 KNOTS WAS NOTED AT KJST
BEFORE 0700 UTC...IN THE VICINITY OF SOME OF THE SHOWERS. THIS
APPEARS TO BE CLOSE TO THE NOSE OF THE 45 KNOT LOW LEVEL...AND THE
CONVECTIVE NATURE OF THE SHOWERS COULD BE HELPING TO MIX MOMENTUM
DOWN. FOR NOW...WILL CONTINUE TO MONITOR THE TRENDS IN GUSTS ACROSS
CENTRAL PENNSYLVANIA...AND ADD STRONGER WIND GUSTS TO THE FORECAST
AS NEEDED.
NEAR AND SHORT TERM MODELS PLACE THE AREA OF SHOWERS ALONG THE I-95
CORRIDOR CLOSE TO SUNRISE...AND MAINLY NORTHEAST OF THE AREA LATE
THIS MORNING. AN ATTEMPT TO PLACE THE BEST CHANCE OF SHOWERS WAS
MADE BASED ON THE POSITION OF THE LOW LEVEL JET AND THE SURFACE
TROUGH. MOST OF THE SHOWER ACTIVITY SHOULD MISS NORTHEAST
MARYLAND...DELAWARE AND SOUTHERN NEW JERSEY. HOWEVER...SMALL
CONVECTIVE LOOKING SHOWERS HAVE DEVELOPED IN THESE AREAS...AND A
CHANCE OF SHOWERS WILL HAVE TO BE CARRIED FOR THIS ACTIVITY THROUGH
AT LEAST SUNRISE.
THE PASSAGE OF THE TROUGH (OR PERHAPS WEAK COLD FRONT) WILL ALLOW
THE DEPTH OF THE MIXED LAYER TO INCREASE. THE INCREASED MIXED LAYER
WILL ALLOW ACCESS TO 25 TO 30 KNOTS OF WIND IN THE WAKE OF THE
TROUGH...AND FOR A FEW HOURS AFTER. THIS SHOULD RESULT IN WEST WINDS
GUSTING TO 25 MPH FOR A TIME THIS AFTERNOON IN JUST ABOUT ALL AREAS.
SKIES SHOULD BECOME PARTLY SUNNY AFTER THE SURFACE TROUGH PASSAGE
(SOUTHERNMOST AREAS MAY BE PARTLY SUNNY THE ENTIRE TIME) AS MIXING
ALLOWS DRIER AIR FROM ABOVE TO BREAK THE LOWER CLOUDS. THE MID DECK
MAY TAKE THE BALANCE OF THE AFTERNOON TO CLEAR THE AREA. THIS IS
MENTIONED BECAUSE OF THE EFFECT ON TEMPERATURES. THE AIRMASS IS EVEN
WARMER AHEAD OF THE TROUGH EARLY THIS MORNING THEN IS WAS MONDAY
AFTERNOON.
WITH ALL THINGS BEING EQUAL...THIS WOULD RESULT IN HIGHER MAXIMUM
TEMPERATURES TODAY. HOWEVER...CLOUD COVER WILL BE A BIG ISSUE. MOST
OF THE REAL WARMING MAY HAVE TO WAIT UNTIL AFTER THE WINDS SHIFT AND
BETTER MIXING CAN OCCUR. THIS MEANS THAT HIGHS MAY NOT GET QUITE AS
HIGH AS THE HIGHER GFS MOS NUMBER SUGGEST. FOR NOW...A BLEND OF MOS
NUMBERS WAS USED FOR HIGHS TODAY...AND THIS COULD BE TWEAKED LATER
THIS MORNING IF THE CLOUD COVER IS NOT AS EXTENSIVE AS IT LOOKS LIKE
IT WILL BE.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
THE SURFACE FRONT/TROUGH WILL STALL SOUTH OF THE AREA THIS EVENING.
WHILE THERE IS SOME MODEL SPREAD ON JUST HOW FAR SOUTH THE FRONT
GETS...ALL SHORT RANGE MODELS DEVELOP A SURFACE LOW ON THE FRONT. AT
THIS POINT...THE POSITION OF THE SURFACE LOW DOES NOT LOOK AS
IMPORTANT AS THE POSITION OF THE MID LEVEL FORCING FOR RAIN TONIGHT.
ALL SHORT RANGE MODELS SHOW AN AREA OF 700-500 MB FRONTOGENETIC
FORCING DEVELOPING AHEAD OF THE SHORT RANGE APPROACHING FROM THE
WEST. MOST PLACE THE BEST MID LEVEL FORCING ACROSS NORTHEAST
MARYLAND...MUCH OF DELAWARE...AS WELL AS SOUTHERNMOST NEW JERSEY.
THIS PLACEMENT HAS BEEN MORE OR LESS CONSISTENT OVER THE PAST 24
HOURS OR SO...AND WAS USED AS THE BASIS FOR THE BEST CHANCE OF RAIN
LATER TONIGHT.
THE AIRMASS ACROSS SOUTHERN AREAS DOES NOT GET A CHANCE TO DRY OUT
AS CENTRAL AND NORTHERN AREAS DO. THERE COULD BE SOME INITIAL LIGHT
RAIN ACROSS SOUTHERNMOST AREAS BEFORE MIDNIGHT...BUT MOST OF THE
STEADY LIGHT RAIN SHOULD OCCUR WITH THE DEVELOPMENT AND MOVEMENT OF
THE BEST MID LEVEL FORCING. THE BEST MID LEVEL LIFT SHOULD OCCUR
BETWEEN 0600 UTC AND 1200 UTC THURSDAY...WITH THE EMPHASIS LATER IN
THE PERIOD.
AGAIN...WHILE THERE IS SOME DIFFERENCE IN THE PLACEMENT OF THE
NORTHERN EDGE OF THE PRECIPITATION WITH THIS EVENT...IT WOULD APPEAR
THAT MOST PLACES SOUTH OF A KTHV-KILG-KACY SHOULD REMAIN DRY THROUGH
1200 UTC THURSDAY. THERE COULD BE SOME PLAY IN THE POSITION OF THIS
LINE...AND A SLIGHT CHANCE OF RAIN WILL BE FORECAST NORTH OF IT TO
INDICATE SOME REMAINING UNCERTAINTY.
MUCH OF THE REST OF THE AREA SHOULD REMAIN DRY...WITH VARYING CLOUD
HEIGHTS OVERNIGHT. CLEARING ACROSS THE NORTH SHOULD BE REPLACED BY
HIGH ALTOSTRATUS...AND CENTRAL AREAS COULD SEE THE MID CLOUDS LOWER
TOWARD DAYBREAK. IN ANY EVENT...THE MOS BLEND LOOKS OK FOR LOWS
TONIGHT...AND THERE WAS A LEAN TOWARD THE HIGHER NAM MOS NUMBERS DUE
TO THE CLOUDS.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODEL GUIDANCE DOES NOT ENGENDER MUCH IN THE WAY OF CONFIDENCE AS
SOLUTIONS SEEM TO VARY AT LEAST SOMEWHAT FROM RUN TO RUN...AS WELL
AS MODEL TO MODEL FOR THE LATTER TIME PERIODS. AN INITIAL ZONAL FLOW
ALOFT FOR MUCH OF THE COUNTRY LOOKS TO SEGUE INTO SOMEWHAT OF A
BLOCKING REGIME LATER FRIDAY AND OVER THE WEEKEND...THEN RETURN TO
MORE OF A ZONAL CONFIGURATION EARLY NEXT WEEK. FOR OUR AREA, IT
APPEARS THAT WE WILL HAVE SEVERAL UPPER TROUGH PASSAGES IN A HIGH
SPEED UPPER FLOW PATTERN. HOW THIS TRANSLATES TO SENSIBLE WEATHER
FOR OUR AREA REMAINS PROBLEMATICAL. AT THE SURFACE, THE 00Z GFS
TRANSITS A WAVE ALONG THE STALLED BOUNDARY TO OUR SOUTH THURSDAY,
MAINLY IN THE MORNING, FOLLOWED BY A PERIOD OF HIGH PRESSURE INTO
SATURDAY. THEN, THE GFS RESOLVES ANOTHER WAVE PASSING TO OUR SOUTH
SATURDAY NIGHT INTO SUNDAY. THIS LOW IS EJECTED FROM A CLOSED UPPER
LOW OVER THE MID MISSISSIPPI VALLEY, BUT THEN IS CAPTURED BY A
DEVELOPING UPPER TROUGH MOVING SOUTHEASTWARD FROM THE EASTERN GREAT
LAKES BY SUNDAY. THE 00Z ECMWF DECLINES TO PASS THE SURFACE LOW EAST
OF ITS MIDWEST UPPER CLOSED LOW...INSTEAD BUILDING HIGH PRESSURE FOR
US FOR THE WEEKEND AND BRINGING A FRONT INTO THE AREA FOR MONDAY
NIGHT INTO EARLY TUESDAY. WITH DIFFERENT FORECASTS, IT WAS DECIDED
JUST TO INTRODUCE SLIGHT CHANCE PROBABILITIES TO OUR FAR SOUTHERN
ZONES SATURDAY NIGHT. THICKNESS CONSIDERATIONS DICTATED THAT A MIX
OF RAIN OR SNOW SHOWERS BE USED ON THE NORTHERN FRINGE OF THIS LOW
CHANCE EVENT. THIS WILL CARRY INTO THE INHERITED CHANCE
PROBABILITIES FOR SUNDAY AND INTO MONDAY. IT MAY TURN OUT THAT THE
LOW CHANCE PROBABILITIES FOR LATER SUNDAY INTO MONDAY ARE OVERDONE,
BUT FOR NOW CONTINUITY WAS USED. THEN, ONLY A SLIGHT CHANCE WAS
INTRODUCED FOR MONDAY NIGHT AND TUESDAY FOR CENTRAL AND NORTHERN
ZONES WITH THE INDICATED FRONTAL PASSAGE ON THE ECMWF.
ALTHOUGH TEMPERATURES MAY DIP AND RECOVER SLIGHTLY THROUGH THE
PERIOD, THEY ARE EXPECTED TO REMAIN ABOVE NORMAL THROUGH NEXT
TUESDAY AS COLD AIR REMAINS UNABLE TO PENETRATE SOUTHWARD TO OUR
LATITUDE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A WAVE OF LOW PRESSURE PASSING TO OUR SOUTH THURSDAY...MAINLY IN THE
MORNING...SHOULD HAVE LITTLE EFFECT FOR OUR TAF SITES. ANOTHER WAVE
MAY PASS TO OUR SOUTH SATURDAY NIGHT INTO SUNDAY...BUT EVEN IF THAT
MATERIALIZED IT SHOULD HAVE MINIMAL IMPACT AS WELL. SO, VFR
CONDITIONS ARE EXPECTED THURSDAY AND RIGHT THROUGH THE OUTLOOK
PERIOD. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
THE APPROACHING LOW LEVEL JET IS DROPPING ENOUGH LOW LEVEL MOMENTUM
AT THE HIGHER PLATFORMS ON THE DELAWARE BAY FOR GUSTS AT OR ABOVE 25
KNOTS. SINCE THE LOW LEVEL JET WILL TAKE MOST OF THE MORNING TO
CLEAR THE REGION...A SMALL CRAFT ADVISORY WAS ISSUED FOR THE
DELAWARE BAY. THIS IS IN ADDITION TO THE SMALL CRAFT ADVISORY THAT
WAS IN PLACE FOR THE OCEAN WATERS...DUE MAINLY TO THE LOW LEVEL JET.
THE SURFACE GRADIENT EARLY THIS MORNING LOOKS AS THOUGH IT CAN
SUPPORT SMALL CRAFT WIND GUSTS ON THE OCEAN...AND THE GRADIENT
SHOULD REMAIN IN PLACE AHEAD OF THE SURFACE TROUGH. MODEL SOUNDINGS
DO NOT SHOW THAT MUCH MOMENTUM TRANSFER (NOT UNUSUAL DURING STRONG
WARM AIR ADVECTION SCENARIOS)...SO THE SMALL CRAFT WINDS PROBABLY
OCCUR MOSTLY BEFORE 1500 UTC. THE SAME IS TRUE ON DELAWARE
BAY...WHERE THE STRONGEST WINDS PROBABLY OCCUR NEARSHORE AND ACROSS
THE MOUTH OF THE BAY.
IN ADDITION...THE SOUTHWEST WIND IS CREATING A SWELL...WHICH
COMBINED WITH THE LOCAL WIND WAVE IS NEAR 5 FEET. THIS PROBABLY
PERSISTS THROUGH THE SURFACE TROUGH PASSAGE...AND PERHAPS A FEW
HOURS AFTER...AS THE SWELL SORTS ITSELF OUT. BASED ON THE
ABOVE...THERE IS NO CHANGE TO THE TIMING OF THE SMALL CRAFT ADVISORY
THROUGH EARLY AFTERNOON.
MODEL SOUNDINGS SHOW SOME MOMENTUM TRANSFER THIS AFTERNOON AS THE
GRADIENT INCREASES AND SLIGHTLY COOLER AIR STREAMS OUT OVER THE
WATERS. RIGHT NOW...THE GRADIENT DOES NOT APPEAR TO SUPPORT SMALL
CRAFT WINDS...AND GUSTS OF THAT MAGNITUDE COULD BE CONFINED TO THE
IMMEDIATE COAST. LATER FORECASTS MAY HAVE TO ACCOUNT FOR THIS AFTER
THE TROUGH PASSES.
THE BEST MOMENTUM ENDS THIS EVENING...AND WINDS AND SEAS WILL DROP
BELOW SMALL CRAFT LEVELS. A SURFACE LOW DEVELOPING ON THE PASSING
SURFACE TROUGH/FRONT SHOULD STILL BE IN THE INCIPIENT STAGE LATER
TONIGHT AS IT APPROACHES THE NORTH CAROLINA/VIRGINIA BORDER. WINDS
WILL SHIFT TO THE NORTH AND NORTHEAST IN RESPONSE TO THE SURFACE LOW
DEVELOPMENT...BUT RIGHT NOW IT APPEARS AS THOUGH WINDS AND SEAS WILL
REMAIN BELOW SMALL CRAFT LEVELS THROUGH 1200 UTC THURSDAY.
A WAVE PASSING JUST SOUTH OF OUR AREA THURSDAY MORNING WILL CAUSE
THE GRADIENT TO TIGHTEN UP...PROBABLY ENOUGH TO INDUCE SMALL CRAFT
ADVISORY LEVEL WINDS. SEAS WILL LIKELY RESPOND AS WELL, BUT THEY ARE
NOT EXPECTED TO RISE ABOVE 4 FEET AT THIS TIME. HIGH PRESSURE WILL
BUILD ACROSS OUR REGION LATER THURSDAY AND REMAIN INTO SATURDAY.
ANOTHER WAVE OF LOW PRESSURE MIGHT PASS JUST TO OUR SOUTH SATURDAY
NIGHT INTO SUNDAY. IF IT DOES, IT COULD INTENSIFY AS IT MOVES OUT
INTO THE WESTERN ATLANTIC...AND THIS MAY RESULT IN MORE SMALL
CRAFT ADVISORY CONDITIONS, BUT FOR NOW LOW CONFIDENCE EXISTS ON
THAT.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...
NEAR TERM...HAYES
SHORT TERM...HAYES
LONG TERM...
AVIATION...HAYES/
MARINE...HAYES/
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
133 AM EST WED FEB 1 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL DRAG A COLD FRONT THROUGH OUR AREA
WEDNESDAY AFTERNOON BEFORE STALLING TO OUR SOUTH. ANOTHER AREA OF
LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS JUST
SOUTH OF OUR AREA ON THURSDAY. HIGH PRESSURE WILL THEN RETURN FOR
LATE THURSDAY THROUGH SUNDAY. ANOTHER SYSTEM MAY IMPACT THE REGION
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THIN SPOTS IN THE MID DECK...AS WELL AS RELATIVELY CALM WINDS IN
PROTECTED AREAS...HAS ALLOWED TEMPERATURES TO DROP IN THESE PLACES
AS A RESULT OF RADIATIONAL COOLING. ELSEWHERE...WITH A MID DECK IN
PLACE OR MOVING INTO PLACE...WITH A LIGHT BUT STEADY SOUTHWEST
WIND...TEMPERATURES HAVE BEEN SLOW TO DROP. OTHER THAN
TEMPERATURES IN THE PROTECTED AREAS WARMING WITH END OF
RADIATIONAL COOLING...NO SIGNIFICANT CHANGES WERE MADE TO THE
OVERNIGHT TEMPERATURES.
A BAND OF SHOWERS IS DEVELOPING ON A SURFACE TROUGH ACROSS WEST
CENTRAL PENNSYLVANIA...WHICH EXTENDS BACK INTO SOUTHEAST OHIO. THE
SHOWERS LOOK TO BE FORMING ON THE NOSE OF THE 45 KNOT LOW LEVEL
JET SEEN ON THE 0000 UTC 925 MB ANALYSIS. MOISTURE IS BEING
FUNNELED UP ALONG THE TROUGH...WITH PRECIPITABLE WATER VALUES NEAR
0.90 INCHES HELPING THE SHOWER DEVELOPMENT.
WHILE 0000 UTC SOUNDINGS WHERE DRY...THE BAND OF SHOWERS SHOULD
NOT HAVE MUCH TROUGH MOVING EAST. EXTRAPOLATION AND THE LATEST
HRRR RUN SUGGEST THAT THE LEADING EDGE OF THE SHOWERS COULD BE IN
THE LEHIGH VALLEY BEFORE 0900 UTC...AND THE AREAL EXTENT OF THE
SHOWERS WAS INCREASED TO ACCOMMODATE THE TIMING. THE COLUMN IS MUCH
TOO WARM FOR ANYTHING OTHER THAN RAIN SHOWERS.
THE BAND OF SHOWERS SHOULD BE IN THE PHILADELPHIA REGION NEAR OR
JUST AFTER DAYBREAK. THE SHOWERS CHANCES WERE INCREASED TO THE
SOUTHWEST LATE TONIGHT TO ACCOUNT FOR THE SHOWERS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
THE FRONT WILL CROSS OUR REGION WEDNESDAY. THE THREAT OF SHOWERS
WILL CONTINUE THROUGH THE MORNING HOURS BUT WILL BE ENDING WITH
THE FRONTAL PASSAGE AROUND MIDDAY. SINCE THE FRONTAL ALIGNMENT
WILL BE ALMOST PARALLEL TO THE UPPER AIR FLOW, THE TEMPERATURE
GRADIENT BEHIND THE FRONT WILL BE NEGLIGIBLE. THAT WILL MEAN
ANOTHER UNSEASONABLY MILD DAY WITH HIGHS RANGING FROM AROUND 50
NORTH TO THE LOWER AND MID 60S SOUTH. SKIES WILL BEGIN TO CLEAR
LATER IN THE DAY AS THE FRONT DRIFTS OFF TO THE SOUTH AND EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT MOVES THROUGH WEDNESDAY AND THEN STALLS TO OUR SOUTH. A
LOW PRESSURE SYSTEM WILL DEVELOP AND TRAVEL ALONG THE STALLED
BOUNDARY ON THURSDAY. THIS WILL BRING THE GREATEST CHANCES FOR
MORE RAIN ACROSS THE SOUTHERN PORTIONS OF OUR FORECAST AREA AS THE
CENTER OF THE LOW IS FORECAST TO STAY NEAR OR JUST SOUTH OF OUR
AREA. THIS SYSTEM MOVES THROUGH QUICKLY AND IS WELL OFFSHORE BY
EARLY FRIDAY.
HIGH PRESSURE THEN SETTLES ACROSS OUR AREA FOR FRIDAY INTO SATURDAY.
THIS WILL KEEP THE FORECAST DRY AS THE HIGH REMAINS ACROSS THE
FORECAST AREA BEFORE STARTING TO SLIDE EASTWARD LATE IN THE DAY ON
SATURDAY.
ANOTHER DAY, ANOTHER RUN OF THE MODELS AND YET ANOTHER FLIP FLOP
SCENARIO. THE GUIDANCE IS HAVING A HARD TIME FIGURING OUT WHAT TO DO
WITH THE STRONG UPPER LEVEL TROUGH/CUT OFF LOW THAT DIGS DOWN ACROSS
THE WESTERN UNITED STATES LATER THIS WEEK. WITH NO REAL CONSENSUS WE
PREFER TO GO WITH THE STATUS QUO AND MAKE VERY FEW CHANGES TO THE
FORECAST FROM SATURDAY ONWARD.
THE CURRENT TRENDS INDICATE A DRY PERIOD FROM FRIDAY THROUGH MUCH OF
SUNDAY AND MAYBE EVEN INTO MONDAY AS HIGH PRESSURE AT THE SURFACE
CONTROLS OUR WEATHER. AN UPPER LEVEL TROUGH DIGS DOWN ACROSS OUR
AREA ON SUNDAY BUT NOT MUCH MOISTURE IS AROUND TO SUPPORT MUCH
PRECIPITATION. THERE IS SOME CONSENSUS THAT THE CUT OFF LOW TO OUR
WEST STARTS TO OPEN UP AND MOVE EASTWARD DRAGGING A COLD FRONT
ACROSS OUR AREA ON MONDAY NIGHT. A LOW MAY DEVELOP ON THIS FRONT BUT
WILL PROBABLY BE OFFSHORE AND OUT OF THE AREA BY TUESDAY AFTERNOON.
WITH NO BIG CHANGES ANTICIPATED IN THE OVERALL PATTERN THROUGH THE
PERIOD, EXPECT NEAR TO MAINLY ABOVE NORMAL TEMPERATURES TO CONTINUE.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A COLD FRONT CLEARS THE AREA EARLY WEDNESDAY EVENING WITH ANY
REMAINING CLOUDS THINNING FROM NORTH TO SOUTH. HOWEVER, ANY LOWER
CLOUDS MAY TAKE A BIT LONGER ACROSS THE SOUTHERN TERMINALS AS
ANOTHER SYSTEM PASSES JUST TO THE SOUTH OF THE AREA. ALL CONDITIONS
WILL BE VFR AS HIGH PRESSURE BUILDS IN FOR LATE THURSDAY THROUGH
SUNDAY. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
THE HIGHER PLATFORMS ON THE DELAWARE BAY ARE SHOWING GUSTS AT OR
ABOVE 25 KNOTS. THIS WOULD SUGGEST THAT AT LEAST SOME OF THE
MOMENTUM ASSOCIATED WITH THE APPROACHING LOW LEVEL JET IS GETTING
CLOSER TO THE BAY SURFACE. SINCE THE LOW LEVEL JET WILL TAKE
THROUGH AT LEAST MID MORNING TO PASS...A SMALL CRAFT ADVISORY HAS
BEEN RAISED ON THE DELAWARE BAY.
OTHERWISE...HIGH PRESSURE TO OUR SOUTH IS PROVIDING A MILD
SOUTHWEST FLOW ACROSS THE AREA. THIS WILL CONTINUE INTO WEDNESDAY,
WHEN A COLD FRONT WILL MOVE IN FROM THE WEST. THE FRONT WILL CROSS
THE WATERS LATE IN THE DAY WEDNESDAY. THE SOUTHWEST FLOW IS
MAINTAINING SEAS NEAR 5 FEET ESPECIALLY FARTHER OFFSHORE. THE LOW-
LEVEL JET FORECAST TO CROSS PARTS OF THE AREA OVERNIGHT MAY MIX
DOWN SOME AS THE BOUNDARY LAYER COOLS. THE AIRMASS JUST ABOVE THE
WATER MAY NOT BE AS COOL AS LATE LAST NIGHT AND EARLY THIS MORNING
WHEN WINDS GUSTED TO AROUND 25 KNOTS FOR A TIME, HOWEVER THE
POTENTIAL IS THERE BASED ON THE SOUNDINGS. GIVEN THIS AND THE SEAS
AT THE OFFSHORE BUOYS IN THE 4-5 FOOT RANGE, A SMALL CRAFT
ADVISORY IS IN EFFECT UNTIL 18Z WEDNESDAY.
THE COLD FRONT CLEARS OUT BY WEDNESDAY NIGHT BUT THE FLOW BEHIND
THE FRONT ISN`T PARTICULARLY STRONG AND WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY LEVELS. A SECOND SYSTEM WILL
MOVE THROUGH ON THURSDAY AND THIS SYSTEM WILL CAUSE THE GRADIENT
TO TIGHTEN UP JUST ENOUGH TO INDUCE SMALL CRAFT ADVISORY LEVEL
WINDS TO OCCUR. SEAS MAY BRIEFLY INCREASE AS WELL BUT THEY ARE NOT
EXPECTED TO GO ABOVE 4 FEET AT THIS TIME.
HIGH PRESSURE WILL BUILD ACROSS THE REGION LATE THURSDAY AND REMAIN
NEARBY THROUGH THE WEEKEND HELP TO KEEP THE WINDS AND SEAS BELOW
ADVISORY CRITERIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NJZ025-
026.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ450>455.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...GORSE
SHORT TERM...RPW
LONG TERM...MEOLA
AVIATION...HAYES/MEOLA
MARINE...GORSE/MEOLA/RPW/HAYES
AREA FORECAST DISCUSSION
NWS MOUNT HOLLY NJ
1215 AM EST WED FEB 1 2012
.SYNOPSIS...
A LOW PRESSURE SYSTEM WILL DRAG A COLD FRONT THROUGH OUR AREA
WEDNESDAY AFTERNOON BEFORE STALLING TO OUR SOUTH. ANOTHER AREA OF
LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY AND PASS JUST
SOUTH OF OUR AREA ON THURSDAY. HIGH PRESSURE WILL THEN RETURN FOR
LATE THURSDAY THROUGH SUNDAY. ANOTHER SYSTEM MAY IMPACT THE REGION
EARLY NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
THIN SPOTS IN THE MID DECK...AS WELL AS RELATIVELY CALM WINDS IN
PROTECTED AREAS...HAS ALLOWED TEMPERATURES TO DROP IN THESE PLACES
AS A RESULT OF RADIATIONAL COOLING. ELSEWHERE...WITH A MID DECK IN
PLACE OR MOVING INTO PLACE...WITH A LIGHT BUT STEADY SOUTHWEST
WIND...TEMPERATURES HAVE BEEN SLOW TO DROP. OTHER THAN
TEMPERATURES IN THE PROTECTED AREAS WARMING WITH END OF
RADIATIONAL COOLING...NO SIGNIFICANT CHANGES WERE MADE TO THE
OVERNIGHT TEMPERATURES.
A BAND OF SHOWERS IS DEVELOPING ON A SURFACE TROUGH ACROSS WEST
CENTRAL PENNSYLVANIA...WHICH EXTENDS BACK INTO SOUTHEAST OHIO. THE
SHOWERS LOOK TO BE FORMING ON THE NOSE OF THE 45 KNOT LOW LEVEL
JET SEEN ON THE 0000 UTC 925 MB ANALYSIS. MOISTURE IS BEING
FUNNELED UP ALONG THE TROUGH...WITH PRECIPITABLE WATER VALUES NEAR
0.90 INCHES HELPING THE SHOWER DEVELOPMENT.
WHILE 0000 UTC SOUNDINGS WHERE DRY...THE BAND OF SHOWERS SHOULD
NOT HAVE MUCH TROUGH MOVING EAST. EXTRAPOLATION AND THE LATEST
HRRR RUN SUGGEST THAT THE LEADING EDGE OF THE SHOWERS COULD BE IN
THE LEHIGH VALLEY BEFORE 0900 UTC...AND THE AREAL EXTENT OF THE
SHOWERS WAS INCREASED TO ACCOMMODATE THE TIMING. THE COLUMN IS MUCH
TOO WARM FOR ANYTHING OTHER THAN RAIN SHOWERS.
THE BAND OF SHOWERS SHOULD BE IN THE PHILADELPHIA REGION NEAR OR
JUST AFTER DAYBREAK. THE SHOWERS CHANCES WERE INCREASED TO THE
SOUTHWEST LATE TONIGHT TO ACCOUNT FOR THE SHOWERS.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
THE FRONT WILL CROSS OUR REGION WEDNESDAY. THE THREAT OF SHOWERS
WILL CONTINUE THROUGH THE MORNING HOURS BUT WILL BE ENDING WITH
THE FRONTAL PASSAGE AROUND MIDDAY. SINCE THE FRONTAL ALIGNMENT
WILL BE ALMOST PARALLEL TO THE UPPER AIR FLOW, THE TEMPERATURE
GRADIENT BEHIND THE FRONT WILL BE NEGLIGIBLE. THAT WILL MEAN
ANOTHER UNSEASONABLY MILD DAY WITH HIGHS RANGING FROM AROUND 50
NORTH TO THE LOWER AND MID 60S SOUTH. SKIES WILL BEGIN TO CLEAR
LATER IN THE DAY AS THE FRONT DRIFTS OFF TO THE SOUTH AND EAST.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
THE FRONT MOVES THROUGH WEDNESDAY AND THEN STALLS TO OUR SOUTH. A
LOW PRESSURE SYSTEM WILL DEVELOP AND TRAVEL ALONG THE STALLED
BOUNDARY ON THURSDAY. THIS WILL BRING THE GREATEST CHANCES FOR
MORE RAIN ACROSS THE SOUTHERN PORTIONS OF OUR FORECAST AREA AS THE
CENTER OF THE LOW IS FORECAST TO STAY NEAR OR JUST SOUTH OF OUR
AREA. THIS SYSTEM MOVES THROUGH QUICKLY AND IS WELL OFFSHORE BY
EARLY FRIDAY.
HIGH PRESSURE THEN SETTLES ACROSS OUR AREA FOR FRIDAY INTO SATURDAY.
THIS WILL KEEP THE FORECAST DRY AS THE HIGH REMAINS ACROSS THE
FORECAST AREA BEFORE STARTING TO SLIDE EASTWARD LATE IN THE DAY ON
SATURDAY.
ANOTHER DAY, ANOTHER RUN OF THE MODELS AND YET ANOTHER FLIP FLOP
SCENARIO. THE GUIDANCE IS HAVING A HARD TIME FIGURING OUT WHAT TO DO
WITH THE STRONG UPPER LEVEL TROUGH/CUT OFF LOW THAT DIGS DOWN ACROSS
THE WESTERN UNITED STATES LATER THIS WEEK. WITH NO REAL CONSENSUS WE
PREFER TO GO WITH THE STATUS QUO AND MAKE VERY FEW CHANGES TO THE
FORECAST FROM SATURDAY ONWARD.
THE CURRENT TRENDS INDICATE A DRY PERIOD FROM FRIDAY THROUGH MUCH OF
SUNDAY AND MAYBE EVEN INTO MONDAY AS HIGH PRESSURE AT THE SURFACE
CONTROLS OUR WEATHER. AN UPPER LEVEL TROUGH DIGS DOWN ACROSS OUR
AREA ON SUNDAY BUT NOT MUCH MOISTURE IS AROUND TO SUPPORT MUCH
PRECIPITATION. THERE IS SOME CONSENSUS THAT THE CUT OFF LOW TO OUR
WEST STARTS TO OPEN UP AND MOVE EASTWARD DRAGGING A COLD FRONT
ACROSS OUR AREA ON MONDAY NIGHT. A LOW MAY DEVELOP ON THIS FRONT BUT
WILL PROBABLY BE OFFSHORE AND OUT OF THE AREA BY TUESDAY AFTERNOON.
WITH NO BIG CHANGES ANTICIPATED IN THE OVERALL PATTERN THROUGH THE
PERIOD, EXPECT NEAR TO MAINLY ABOVE NORMAL TEMPERATURES TO CONTINUE.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
VFR CONDITIONS CONTINUE EARLY THIS MORNING WITH MID LEVEL CLOUDINESS
ACROSS THE AREA. MID LEVEL CLOUDINESS WILL LOWER AS AN AREA OF
SHOWERS ASSOCIATED WITH A SURFACE TROUGH MOVE EAST FROM WEST
CENTRAL PENNSYLVANIA. TO THIS POINT...CONDITIONS HAVE REMAINED VFR
EVEN IN LOCATIONS WITH SHOWERS...WHICH ARE NOT LASTING LONG.
THE LEADING EDGE OF THE LINE OF SHOWERS SHOULD REACH THE LEHIGH
VALLEY BEFORE 0900 UTC. THIS IS BASED ON EXTRAPOLATION...AND IS
SUPPORTED BY THE LATEST HRRR RUN. AN EXPLICIT MENTION OF SHOWERS WAS
CARRIED FOR MOST PLACES (OUTSIDE OF KACY AND KMIV) BETWEEN 0900 UTC
AND 1400 UTC...MOVING FROM WEST TO EAST. AGAIN...CONDITIONS SHOULD
REMAIN VFR WITH THE SHOWERS...BASED ON WHAT IS OCCURRING TO THE
WEST...AND THAT IS WHAT THE 0600 UTC TERMINAL FORECASTS WILL INDICATE.
AHEAD OF THE FRONT...A LOW LEVEL JET IS ABOUT TO MOVE THROUGH THE
AREA. 0000 UTC SOUNDINGS AND RECENT AMDAR SOUNDINGS FROM KPHL SHOW
40 TO 45 KNOTS OF WINDS FROM THE SOUTHWEST. THIS SHOULD CONTINUE
THROUGH THE TROUGH PASSAGE...WHEN WINDS IN ALL LEVELS BECOME
UNIDIRECTIONAL FROM THE WEST.
AFTER THE TROUGH PASSAGE...THE LOW LEVEL MOISTURE AVAILABLE FOR MORE
PRECIPITATION LOOKS TO BE SCOURED...AND DRY CONDITIONS ARE EXPECTED
FOR THE BALANCE OF THE DAY. AFTER THE TROUGH PASSAGE...THE DEPTH OF
THE MIXED LAYER INCREASES TO ABOUT 4000 FEET...WHICH WILL ALLOW
ACCESS TO 25 TO 30 KNOTS OF WIND. THIS SHOULD TRANSLATE TO 19 TO 22
KNOT WIND GUSTS FROM THE WEST BETWEEN 1700 UTC AND 2200 UTC FOR MOST
LOCATIONS.
THE GRADIENT DROPS OFF AFTER 2200 UTC...AND THE GUSTINESS WILL DROP
OFF AS WELL. THE TROUGH THAT PASSES WILL STALL TO THE SOUTH OF THE
AREA TONIGHT. THIS WILL RESULT IN VFR CEILINGS FROM KPHL SOUTH...BUT
AS OF NOW ALL LOCATIONS SHOULD REMAIN DRY THROUGH 1200 UTC THURSDAY.
OUTLOOK...
A COLD FRONT CLEARS THE AREA EARLY WEDNESDAY EVENING WITH ANY
REMAINING CLOUDS THINNING FROM NORTH TO SOUTH. HOWEVER, ANY LOWER
CLOUDS MAY TAKE A BIT LONGER ACROSS THE SOUTHERN TERMINALS AS
ANOTHER SYSTEM PASSES JUST TO THE SOUTH OF THE AREA. ALL CONDITIONS
WILL BE VFR AS HIGH PRESSURE BUILDS IN FOR LATE THURSDAY THROUGH
SUNDAY. A PERIOD OF GUSTY WINDS IS POSSIBLE LATE THURSDAY INTO
FRIDAY.
&&
.MARINE...
HIGH PRESSURE TO OUR SOUTH IS PROVIDING A MILD SOUTHWEST FLOW
ACROSS THE AREA. THIS WILL CONTINUE INTO WEDNESDAY, WHEN A COLD
FRONT WILL MOVE IN FROM THE WEST. THE FRONT WILL CROSS THE WATERS
LATE IN THE DAY WEDNESDAY. THE SOUTHWEST FLOW IS MAINTAINING SEAS
NEAR 5 FEET ESPECIALLY FARTHER OFFSHORE. THE LOW-LEVEL JET
FORECAST TO CROSS PARTS OF THE AREA OVERNIGHT MAY MIX DOWN SOME AS
THE BOUNDARY LAYER COOLS. THE AIRMASS JUST ABOVE THE WATER MAY NOT
BE AS COOL AS LATE LAST NIGHT AND EARLY THIS MORNING WHEN WINDS
GUSTED TO AROUND 25 KNOTS FOR A TIME, HOWEVER THE POTENTIAL IS THERE
BASED ON THE SOUNDINGS. GIVEN THIS AND THE SEAS AT THE OFFSHORE
BUOYS IN THE 4-5 FOOT RANGE, A SMALL CRAFT ADVISORY IS IN EFFECT
UNTIL 18Z WEDNESDAY. WE WILL HOLD OFF ON DELAWARE BAY GIVEN THE
SOUTHWESTERLY TRAJECTORY. WINDS WILL BEGIN TO SWING AROUND TO THE
WEST TOWARD WEDNESDAY EVENING.
THE COLD FRONT CLEARS OUT BY WEDNESDAY NIGHT BUT THE FLOW BEHIND
THE FRONT ISN`T PARTICULARLY STRONG AND WINDS AND SEAS ARE
EXPECTED TO REMAIN BELOW ADVISORY LEVELS. A SECOND SYSTEM WILL
MOVE THROUGH ON THURSDAY AND THIS SYSTEM WILL CAUSE THE GRADIENT
TO TIGHTEN UP JUST ENOUGH TO INDUCE SMALL CRAFT ADVISORY LEVEL
WINDS TO OCCUR. SEAS MAY BRIEFLY INCREASE AS WELL BUT THEY ARE NOT
EXPECTED TO GO ABOVE 4 FEET AT THIS TIME.
HIGH PRESSURE WILL BUILD ACROSS THE REGION LATE THURSDAY AND REMAIN
NEARBY THROUGH THE WEEKEND HELP TO KEEP THE WINDS AND SEAS BELOW
ADVISORY CRITERIA.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ450>455.
&&
$$
SYNOPSIS...MEOLA
NEAR TERM...HAYES
SHORT TERM...RPW
LONG TERM...MEOLA
AVIATION...HAYES/MEOLA
MARINE...GORSE/MEOLA/RPW
AREA FORECAST DISCUSSION
NWS TALLAHASSEE FL
910 PM EST Thu Feb 2 2012
.UPDATE...
02Z water vapor and H4 RUC analysis shows a complex and amplified
upper level pattern across the CONUS this evening. Main feature on
the map is a large trough/closed low spinning over the
inter-mountain west and centered near the four-corners region. This
energy will not be quick to move through the next 24 hours. Weak
ridging ahead of this trough will pivot across the middle/lower MS
valley/SE states through the overnight. However, Global guidance all
in agreement of a series of quickly trailing weak impulses moving
through the deep SW flow ahead of the dominant upper low. This
energy will approach the northern Gulf coast later tonight into
Friday. 03/00Z KTLH sounding still shows a substantial dry layer in
the mid-levels, generally between 600-400mb. Deep moisture moving
northward over the Gulf of Mexico this evening and forecast model
sounding all suggest a moistening of the mid-levels during the next
12 hours, which will prime the column to support a return of shower
chances to our western zones for Friday.
At the surface, strengthening 1028mb high pressure centered over
West Virgina continues to ridge to the NE Gulf of Mexico. This ridge
will translate eastward to the Carolina coast by Friday morning.
Rest of tonight,
A seasonable and generally dry overnight period expected. High/mid
level clouds will slowly be on the increase, with skies becoming
mostly cloudy across much of the forecast area by sunrise.
Temperatures will be seasonable with lows dropping down into the 50s
south and upper 40s to around 50 north. Latest hi-res guidance has
backed off of the showers potential before dawn into our western
zones. Based on this newer guidance and the amount of moistening
still required on the 00z KTLH sounding, will adjust down the 20-30%
PoPs currently in the grids.
Friday,
Weak synoptic support ahead of the mid-level impulses mentioned
above will overspread the area. This really looks to be a marginal
event in terms of shower potential due to the disorganized nature of
the shortwave energy. For now will not make any significant changes
to the grids for the daylight hours. Current PoPs west of
Tallahassee and Albany are around 30%. This looks reasonable, as any
showers should be widely sct and light in nature.
&&
.AVIATION...
VFR conditions are expected to hold across the region tonight and
through the day Friday. VFR ceilings are expected to overspread the
region Friday morning with a chance of showers beginning mid to late
afternoon and spreading from west to east.
&&
.MARINE...
Winds and seas will gradually increase by daybreak on Friday as the
pressure gradient tightens with high pressure building in north of
the marine area. Winds will likely reach cautionary levels on Friday
with a brief period of advisory level winds possible as well. High
pressure will build back over the marine area by Sunday resulting in
lighter winds and seas for the first of the week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 56 70 57 75 54 / 20 20 10 10 10
Panama City 58 69 60 71 60 / 30 30 20 10 20
Dothan 52 68 55 74 58 / 20 30 20 30 20
Albany 50 68 52 75 57 / 10 20 20 30 20
Valdosta 53 70 54 79 55 / 10 10 10 20 10
Cross City 53 74 56 78 55 / 10 10 10 10 10
Apalachicola 60 70 61 70 59 / 30 30 20 10 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
AL...None.
GA...None.
FL...None.
GM...None.
&&
$$
MROCZKA/EVANS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
937 PM EST THU FEB 2 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE OVER NORTHERN INDIANA AND THE SOUTHERN GREAT LAKES
WILL CONTINUE MOVING EAST. MEANWHILE AN UPPER TROUGH OVER THE
CENTRAL ROCKIES WILL DEVELOP INTO A CLOSED UPPER LOW AND MOVE OUR
WAY SATURDAY AND SATURDAY NIGHT. A SURFACE LOW PRESSURE SYSTEM WILL
TRACK ACROSS KENTUCKY AND TENNESSEE SATURDAY AND SATURDAY NIGHT.
HIGH PRESSURE BEHIND THIS SYSTEM WILL BUILD OUR WAY LATE SUNDAY AND
MONDAY. IN THE EXTENDED HIGH PRESSURE WILL DOMINATE OUR WEATHER.
HOWEVER A WEAK AND DRY COLD FRONT WILL MOVE ACROSS OUR REGION AROUND
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
WILL BUMP WORDING UP FOR FOG POTENTIAL TO AREAS OF FOG/PATCHY DENSE
OVERNIGHT...AS LAPS SOUNDINGS AND OBS LOOK VERY SIMILAR TO LAST
NIGHT. SREF PROBABILITIES DO NOT INDICATE FOG...BUT THESE PROGS HAVE
LEFT SOMETHING TO BE DESIRED TO SAY THE LEAST LATELY.
RUC SOUNDINGS SHOW A DEPTH OF MOISTURE NOT QUITE AS DEEP AS LAST
NIGHT...BUT STILL SUBSTANTIAL. ADDED CIRRUS MAY VERY WELL PREVENT
WIDESPREAD NEAR ZERO VISIBILITIES LIKE EXPERIENCED THIS
MORNING...BUT SHOULD STILL ALLOW WIDESPREAD VISIBILITIES BELOW 1
MILE. WILL UPDATE HWO AND ISSUE SPS TO HIGHLIGHT.
OTHERWISE...FEW CHANGES NECESSARY TO GOING FORECAST. DID TWEAK
TEMPERATURES SLIGHTLY BASED ON HOURLY NUMERICAL GUIDANCE AND
OBS/DEWPOINT TRENDS...AND BROUGHT WINDS MORE TOWARDS CALM TO VERY
LIGHT PER LATEST OBS.
PREVIOUS DISCUSSION FOLLOWS.
AREAS OF FOG AND STRATUS EARLIER OVER THE WESTERN PART OF OUR REGION
HAS TAKEN MOST OF THE DAY TO CLEAR OUT. HIGH PRESSURE WILL BRING
LIGHT WINDS AND MOSTLY CLEAR SKIES EARLY ON AND THERE IS SOME
POTENTIAL FOG SOME FOG AGAIN TONIGHT. ON THE OTHER HAND...THERE
WILL BE MORE CIRRUS MOVING IN OVERNIGHT WHICH WOULD LESSEN THE
POTENTIAL FOR FOG. THE 15Z VSREF SHOWS PRACTICALLY NO POTENTIAL FOR
FOG...WHILE THE RUC SOUNDINGS INDICATE A MUCH GREATER POTENTIAL FOG
FOG. THE WINDS AND CLOUDS LATER TONIGHT WILL LESSEN THE POTENTIAL
QUITE A BIT. BUT WITH SOME UNCERTAINTY WILL MENTION PATCHY FOG MOST
AREAS LATE TONIGHT. I DON`T THINK THERE WILL BE WIDESPREAD DENSE
FOG AS THERE WAS LAST NIGHT.
WITH CLEAR SKIES AND LIGHT WINDS WILL UNDERCUT MOS TEMPERATURES A
LITTLE TONIGHT. MOST AREAS LAST NIGHT ENDED SEVERAL DEGREES COOLER.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
THE HIGHEST DEWPOINTS AND LIGHTEST WINDS WILL BE ACROSS OUR NORTH
AND NORTHEAST SECTIONS FRIDAY MORNING. WILL MENTION SOME PATCHY FOG
ALL BUT FAR SOUTHWEST EARLY FRIDAY. OTHERWISE...FRIDAY WILL BE
ANOTHER VERY NICE DAY WITH INCREASING HIGH CLOUDS. WENT CLOSE TO A
MET/MAV BLEND ON TEMPERATURES.
ALL MODELS SPREAD RAIN INTO OUR REGION FRIDAY NIGHT AND SATURDAY
APPEARS TO BE A VERY WET DAY WITH PERIODS OF RAIN MOST AREAS. BUT
WITH SLIGHTLY LESSER CHANCES ACROSS OUR FAR NORTH. AS FAR AS
TEMPERATURES WENT SLIGHTLY ABOVE MAV/MET BLEND FRIDAY NIGHT AND
SLIGHTLY BELOW SATURDAY AS CLOUDS AND PRECIP SHOULD LIMIT ANY
DIURNAL TREND ON TEMPERATURES.
1000 TO 850 MB THICKNESS DROP TO NEAR OR SLIGHTLY BELOW 1300 METERS
LATE SATURDAY NIGHT ACROSS OUR NORTH AND WILL MENTION CHANCE OF
MIXED PRECIP THERE. BUT IT IS POSSIBLE THE PRECIP MAY BE OVER
ACROSS OUR NORTH BY THAT TIME.
MODELS START TO MOVE THE UPPER LOW TO THE SOUTHEAST AS AN UPPER
RIDGE DEVELOPS OVER THE NORTHERN PLAINS. JUST ABOUT ALL MODELS NOW
LEAN TOWARDS A DRY DAY SUNDAY. BUT WITH AN UPPER TROUGH STILL OVER
OUR REGION 12Z-18Z SUNDAY...I AM STILL A BIT RELUCTANT TO JUMP ON
THE DRY BAND WAGON YET SUNDAY WITH THE POSSIBLE EXCEPTION OF OUR
NORTHERN AREAS WOULD DRY OUT FIRST. EITHER CASE...ANY REMAINING
PRECIP WILL END DURING THE DAY SUNDAY AS THE UPPER TROUGH MOVES TO
THE SOUTHEAST. DID NOT MAKE ANY SIGNIFICANT CHANGES TO TEMPERATURES
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
QUIET PATTERN FOR THE LONG TERM. MODELS ARE MOVING THE TROUGH AXIS
THROUGH A LITTLE BIT FASTER SUNDAY SO BY SUNDAY NIGHT IT LOOKS LIKE
ALL PRECIP SHOULD HAVE MOVED OUT OF THE AREA. WITH THE VESTIGES OF
AN UPPER LOW STILL HANGING AROUND UPSTREAM AND MOVING ACROSS ON
MONDAY COULD SEE A LITTLE INCREASED CLOUD COVER BUT THAT/S IT GIVEN
THE LACK OF MOISTURE AND LACK OF FORCING. AFTER THAT MOVES THROUGH
MONDAY UPPER FLOW INCLUDES A DEEP UPPER LOW MOVING INTO ST JAMES BAY
AND ANOTHER UPPER LOW DIGGING INTO WESTERN MEXICO BUT VERY LITTLE
GOING ON ELSEWHERE. TEMPERATURES LOOK A LITTLE WARMER THAN AVERAGE
FOR THIS TIME OF YEAR BUT ALLBLEND CAPTURED THIS WELL. ONLY CHANGES
TO ALLBLEND FOR POPS WAS TO REMOVE SLIGHT CHANCE IN THE SOUTH ON
SUNDAY NIGHT DUE TO FASTER MOVEMENT OF THE TROUGH AND REMOVAL OF
SLIGHT CHANCE POPS IN DAY 7 WITH ENSEMBLES AND OPERATIONAL GFS
FAVORING DRY.
&&
.AVIATION /DISCUSSION FOR 020300Z TAF UPDATE/...
NO MAJOR CHANGES. TWEAKED TIMES OF FOG FORMATION BASED ON 02Z
DEWPOINT SPREADS. PREVIOUS DISCUSSION FOLLOWS.
BY FAR THE MOST IMPORTANT QUESTION IS FOG AND VISIBILITIES. WE
HAVE HAD A DAY TO DRY SOIL SOMEWHAT...BUT DEWPOINT SPREADS AND
WINDS NOT VERY DIFFERENT FROM SAME TIME LAST NIGHT...WHEN FOG
BECAME WIDESPREAD AND DENSE.
THIS MEANS FOG WILL PROBABLY NOT BE QUITE AS LONG LIVED AND AS
THICK AS DURING THE MORNING...BUT WIDESPREAD IFR VISIBILITIES
FROM 06Z- 14Z. AT TIMES VISIBILITIES VLIFR. RAPID IMPROVEMENT AFTER
SUNRISE WITH VISIBILITIES P6SM BY 16Z.
OTHERWISE...EITHER NO CEILINGS OR CEILINGS ABOVE 10 THOUSAND FEET.
WINDS TOO LIGHT TO AFFECT OPERATIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/NIELD
SHORT TERM...JH
LONG TERM....CP
AVIATION...JK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
915 PM EST THU FEB 2 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE OVER NORTHERN INDIANA AND THE SOUTHERN GREAT LAKES
WILL CONTINUE MOVING EAST. MEANWHILE AN UPPER TROUGH OVER THE
CENTRAL ROCKIES WILL DEVELOP INTO A CLOSED UPPER LOW AND MOVE OUR
WAY SATURDAY AND SATURDAY NIGHT. A SURFACE LOW PRESSURE SYSTEM WILL
TRACK ACROSS KENTUCKY AND TENNESSEE SATURDAY AND SATURDAY NIGHT.
HIGH PRESSURE BEHIND THIS SYSTEM WILL BUILD OUR WAY LATE SUNDAY AND
MONDAY. IN THE EXTENDED HIGH PRESSURE WILL DOMINATE OUR WEATHER.
HOWEVER A WEAK AND DRY COLD FRONT WILL MOVE ACROSS OUR REGION AROUND
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
AREAS OF FOG AND STRATUS EARLIER OVER THE WESTERN PART OF OUR REGION
HAS TAKEN MOST OF THE DAY TO CLEAR OUT. HIGH PRESSURE WILL BRING
LIGHT WINDS AND MOSTLY CLEAR SKIES EARLY ON AND THERE IS SOME
POTENTIAL FOG SOME FOG AGAIN TONIGHT. ON THE OTHER HAND...THERE
WILL BE MORE CIRRUS MOVING IN OVERNIGHT WHICH WOULD LESSEN THE
POTENTIAL FOR FOG. THE 15Z VSREF SHOWS PRACTICALLY NO POTENTIAL FOR
FOG...WHILE THE RUC SOUNDINGS INDICATE A MUCH GREATER POTENTIAL FOG
FOG. THE WINDS AND CLOUDS LATER TONIGHT WILL LESSEN THE POTENTIAL
QUITE A BIT. BUT WITH SOME UNCERTAINTY WILL MENTION PATCHY FOG MOST
AREAS LATE TONIGHT. I DON`T THINK THERE WILL BE WIDESPREAD DENSE
FOG AS THERE WAS LAST NIGHT.
WITH CLEAR SKIES AND LIGHT WINDS WILL UNDERCUT MOS TEMPERATURES A
LITTLE TONIGHT. MOST AREAS LAST NIGHT ENDED SEVERAL DEGREES COOLER.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
THE HIGHEST DEWPOINTS AND LIGHTEST WINDS WILL BE ACROSS OUR NORTH
AND NORTHEAST SECTIONS FRIDAY MORNING. WILL MENTION SOME PATCHY FOG
ALL BUT FAR SOUTHWEST EARLY FRIDAY. OTHERWISE...FRIDAY WILL BE
ANOTHER VERY NICE DAY WITH INCREASING HIGH CLOUDS. WENT CLOSE TO A
MET/MAV BLEND ON TEMPERATURES.
ALL MODELS SPREAD RAIN INTO OUR REGION FRIDAY NIGHT AND SATURDAY
APPEARS TO BE A VERY WET DAY WITH PERIODS OF RAIN MOST AREAS. BUT
WITH SLIGHTLY LESSER CHANCES ACROSS OUR FAR NORTH. AS FAR AS
TEMPERATURES WENT SLIGHTLY ABOVE MAV/MET BLEND FRIDAY NIGHT AND
SLIGHTLY BELOW SATURDAY AS CLOUDS AND PRECIP SHOULD LIMIT ANY
DIURNAL TREND ON TEMPERATURES.
1000 TO 850 MB THICKNESS DROP TO NEAR OR SLIGHTLY BELOW 1300 METERS
LATE SATURDAY NIGHT ACROSS OUR NORTH AND WILL MENTION CHANCE OF
MIXED PRECIP THERE. BUT IT IS POSSIBLE THE PRECIP MAY BE OVER
ACROSS OUR NORTH BY THAT TIME.
MODELS START TO MOVE THE UPPER LOW TO THE SOUTHEAST AS AN UPPER
RIDGE DEVELOPS OVER THE NORTHERN PLAINS. JUST ABOUT ALL MODELS NOW
LEAN TOWARDS A DRY DAY SUNDAY. BUT WITH AN UPPER TROUGH STILL OVER
OUR REGION 12Z-18Z SUNDAY...I AM STILL A BIT RELUCTANT TO JUMP ON
THE DRY BAND WAGON YET SUNDAY WITH THE POSSIBLE EXCEPTION OF OUR
NORTHERN AREAS WOULD DRY OUT FIRST. EITHER CASE...ANY REMAINING
PRECIP WILL END DURING THE DAY SUNDAY AS THE UPPER TROUGH MOVES TO
THE SOUTHEAST. DID NOT MAKE ANY SIGNIFICANT CHANGES TO TEMPERATURES
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
QUIET PATTERN FOR THE LONG TERM. MODELS ARE MOVING THE TROUGH AXIS
THROUGH A LITTLE BIT FASTER SUNDAY SO BY SUNDAY NIGHT IT LOOKS LIKE
ALL PRECIP SHOULD HAVE MOVED OUT OF THE AREA. WITH THE VESTIGES OF
AN UPPER LOW STILL HANGING AROUND UPSTREAM AND MOVING ACROSS ON
MONDAY COULD SEE A LITTLE INCREASED CLOUD COVER BUT THAT/S IT GIVEN
THE LACK OF MOISTURE AND LACK OF FORCING. AFTER THAT MOVES THROUGH
MONDAY UPPER FLOW INCLUDES A DEEP UPPER LOW MOVING INTO ST JAMES BAY
AND ANOTHER UPPER LOW DIGGING INTO WESTERN MEXICO BUT VERY LITTLE
GOING ON ELSEWHERE. TEMPERATURES LOOK A LITTLE WARMER THAN AVERAGE
FOR THIS TIME OF YEAR BUT ALLBLEND CAPTURED THIS WELL. ONLY CHANGES
TO ALLBLEND FOR POPS WAS TO REMOVE SLIGHT CHANCE IN THE SOUTH ON
SUNDAY NIGHT DUE TO FASTER MOVEMENT OF THE TROUGH AND REMOVAL OF
SLIGHT CHANCE POPS IN DAY 7 WITH ENSEMBLES AND OPERATIONAL GFS
FAVORING DRY.
&&
.AVIATION /DISCUSSION FOR 020300Z TAF UPDATE/...
NO MAJOR CHANGES. TWEAKED TIMES OF FOG FORMATION BASED ON 02Z
DEWPOINT SPREADS. PREVIOUS DISCUSSION FOLLOWS.
BY FAR THE MOST IMPORTANT QUESTION IS FOG AND VISIBILITIES. WE
HAVE HAD A DAY TO DRY SOIL SOMEWHAT...BUT DEWPOINT SPREADS AND
WINDS NOT VERY DIFFERENT FROM SAME TIME LAST NIGHT...WHEN FOG
BECAME WIDESPREAD AND DENSE.
THIS MEANS FOG WILL PROBABLY NOT BE QUITE AS LONG LIVED AND AS
THICK AS DURING THE MORNING...BUT WIDESPREAD IFR VISIBILITIES
FROM 06Z- 14Z. AT TIMES VISIBILITIES VLIFR. RAPID IMPROVEMENT AFTER
SUNRISE WITH VISIBILITIES P6SM BY 16Z.
OTHERWISE...EITHER NO CEILINGS OR CEILINGS ABOVE 10 THOUSAND FEET.
WINDS TOO LIGHT TO AFFECT OPERATIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH
SHORT TERM...JH
LONG TERM....CP
AVIATION...JK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
233 PM EST WED FEB 1 2012
.UPDATE...
THE LONG TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
A NORTH SOUTH AREA OF HIGH PRESSURE WILL DOMINATE INDIANA WEATHER
INTO FRIDAY. OVER THE WEEKEND LOW PRESSURE WILL MOVE TOWARD AND THEN
CROSS OUR STATE. HIGH PRESSURE IS EXPECTED TO RETURN MONDAY AND A
WEAK COLD FRONT IS FORECAST TO PASS TUESDAY. BY MIDWEEK HIGH
PRESSURE WILL BE BACK.
&&
.NEAR TERM /TONIGHT/...
BOTH SATELLITE OBSERVATIONS AND MODEL MOISTURE FIELDS SUPPORT PARTLY
CLOUDY TONIGHT. THIS LEAVES TEMPERATURES AS FORECAST PROBLEM.
MAV AND MET ARE CLOSE...BUT MET IS JUST SLIGHTLY COOLER. BASED ON
WHAT HAPPENED UPSTREAM LAST NIGHT I WILL USE THE MET.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MAIN PROBLEM IS WHEN PRECIPITATION WILL DEVELOP. ALL THE MODELS
AGREE WE ONLY HAVE TO WORRY ABOUT RAIN.
NAM...AND ASSOCIATED MET...BRING IN RAIN FASTER THAN GFS AND MAV. I
GOING TO UAW THE MAV. LATEST NAM IS NOT VERY CONSISTENT WITH ITS OWN
PREVIOUS RUN...OR THE SREF. THIS SUGGESTS IT IS AN OUTLIER.
FRIDAY NIGHT AND SATURDAY ALL MODELS PUT AT LEAST SOME QPF
EVERYWHERE IN THE CWA. IN MOST PLACES WILL USE LIKELY. EXCEPTION IS
THE EXTREME NORTHEAST FRIDAY NIGHT WHERE I WILL TAKE THE RELATIVELY
LOW POPS TO A HIGH CHANCE.
MAV HAS BEEN DOING WELL WITH TEMPERATURES LATELY. WILL USE THAT
THROUGH FRIDAY NIGHT WITH LITTLE CHANGE. SATURDAY MEX HIGHS ARE
ABOVE THE GFS HIGHS FROM THE MEN. SPLIT BETWEEN MEN HIGHS AND MEN
AVERAGES LOOKS BETTER TO ME GIVEN RAIN IS FORECAST.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
CLOUDY DAMP WEEKEND THEN IMPROVING...BUT TREND TOWARD COOLER
WEATHER.
FORECAST PROBLEM REMAINS WITH EVOLUTION AND MOVEMENT OF WEATHER
SYSTEM THIS WEEKEND AND APPEARS BEST BET IS A MELDING OF SOLUTIONS
WITH A LEAN TOWARD SLOWER MODELS WITH GEM PERHAPS A MID-WAY
SOLUTION AMONG ALL. IN THE END THE DIFFERENCE PRIMARILY TIES TO
HOW SOON COLD AIR IN SYSTEM COMMA HEAD WRAPS INTO INDIANA AND
WHETHER OR NOT ANY SNOW WOULD MIX IN.
AT THIS POINT...PRETTY HIGH CONFIDENCE NO SNOW WILL OCCUR UNTIL
LATE SUNDAY NIGHT AND EVEN THAT SHOULD BE LIGHT AND NOT ACCUMULATE
GIVEN THE INTENSITY EXPECTED AND THE WET WARM GROUND THAT WILL
PREVAIL INTO THAT TIME FRAME.
THERE IS SIMILARITY IN THE MODELS...EXCEPT FOR THE SLOWEST...EURO
SOLUTION...IN THAT A DRY SLOT WRAPS INTO CENTRAL INDIANA SATURDAY
NIGHT AND PART OF SUNDAY. THIS WOULD IMPLY ANY RAIN THAT DOES
OCCUR WOULD BE VERY LIGHT...PERHAPS BECOMING MORE OF A DRIZZLE.
CONTINUING INTO SUNDAY...WITH TEMPS AT OR ABOVE FREEZING...AGAIN
EXPECTING NO MORE THAN A LIGHT RAIN OR DRIZZLE...AND POTENTIAL
EXISTS FOR FAIR SHARE OF SAATURDAY NIGHT TO SUNDAY NIGHT HAVING
DRY PERIODS. AS WEATHER SYSTEM CONTINUES TO DEPART TO THE EAST
LINGERING CLOUDS COULD SPIT A FEW FLURRIES MONDAY BUT PROBABILITY
TOO LOW TO CARRY THAT AT THIS POINT. HIGH PRESSURE THEN BEGINS TO
BUILD IN AND CLEAR SKIES LATE TUESDAY INTO WEDNESDAY.
TEMPERATURE-WISE...GIVEN THAT WE WILL REMAIN ON THE WARM SIDE OF
THE OCCLUDED FRONT SATURDAY NIGHT...MINS SHOULD BE MILDER THAN MEX
WHICH IS BASED ON COOLER GFS MODEL. LOOKING AT SUNDAY MORNING MINS
IN THE MID 30S NORTHERN FORECAST AREA TO MID 40S SOUTHERN FORECAST
AREA. SAME TREND FOR SUNDAY DAY WITH MAX TEMPS JUST ABOVE MEX
GUIDANCE OR MID AND UPPER 40S. WITH COLD AIR FINALLY WRAPPING INTO
THE AREA SUNDAY NIGHT...MIN TEMPS MONDAY MORNING WILL REACH THE
LOWER AND MIDDLE 30S...AGAIN SEVERAL DEGREES WARMER THAN MEX
GUIDANCE WITH CLOUD COVER HELPING KEEP TEMPS UP A BIT. COOLER MAX
AND MINS TUESDAY AND WEDNESDAY AS CANADIAN HIGH INCREASES ITS
INFLUENCE SO LOWER 40 MAXS AND MINS DROPPING TO 20S AND LOWER 30S
AS CURRENTLY FORECAST LOOK GOOD.
&&
.AVIATION /DISCUSSION FOR 011800Z TAFS/...
CHALLENGING FORECAST WITH REGARDS TO CEILINGS THIS PERIOD AS SHALLOW
COLD ADVECTIVE CLOUD SHIELD OVER NRN INDIANA/IL HAD BEEN MOVING
SOUTHEAST AROUND 10 KTS UNTIL LAST HOUR WHEN MOVEMENT BECAME NEARLY
STATIONARY. THIS RECENT TREND IS MOST LIKELY RELATED TO GREATER
MIXING THAT HAS DEVELOPED DURING PEAK HEATING ON THE LEADING EDGE OF
THIS SHALLOW CLOUD MASS. AS DIURNAL MIXING WANES AFTER 21Z EXPECT TO
SEE CLOUD MASS MOVE SOUTH TO AT LEAST LAF/MIE AS PER 15Z RUC 950MB
RH FIELDS. GREATER UNCERTAINTY EXISTS WITH DEGREE OF LOW CLOUD
COVERAGE ACROSS REST OF TAF SITES TONIGHT. MAIN CONCERNS FOR LOW
CLOUD COVER TO MOVE INTO REST OF CENTRAL IN IS WARMER ANTECEDANT
GROUND TEMPERATURES AND WEAK CAA ABOVE THE INVERSION WHICH SHOULD
PRECLUDE ANY STRENGTHENING OF THE INVERSION OVERNIGHT. IN FACT THIS
CAA MAY ACTUALLY REDUCE THE INVERSION SUFFICIENTLY FOR THE LOW
CLOUDS TO CLEAR OUT COMPLETELY LATER THIS EVENING. ONCE MID-HIGH
CLOUD BANDS ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER KS/NE MOVE
AWAY FROM THE AREA AFTER 06Z MOSTLY CLEAR SKIES SHOULD LEAD TO THE
FORMATION OF LOWER VSBYS WITH SOME PATCHY GROUND FOG. CONF FOR FOG
IS NOT HIGH ENOUGH ATTM FOR SHOWING ANYTHING MORE THAN 1-3SM VIS AND
BR AT KLAF/KBMG AND KHUF TAFS WITH SLIGHTLY HIGHER VIS FCST AT KIND
OWING TO EFFECTS OF URBAN ENVIRONMENT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....TDUD
AVIATION...CROSBIE/TUCEK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1247 PM EST WED FEB 1 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM AND SHORT TERM SECTIONS HAVE BEEN UPDATED
BELOW
&&
.SYNOPSIS...
A NORTH SOUTH AREA OF HIGH PRESSURE WILL DOMINATE INDIANA WEATHER
INTO FRIDAY. OVER THE WEEKEND LOW PRESSURE WILL MOVE TOWARD AND THEN
CROSS OUR STATE. HIGH PRESSURE IS EXPECTED TO RETURN MONDAY AND A
WEAK COLD FRONT IS FORECAST TO PASS TUESDAY. BY MIDWEEK HIGH
PRESSURE WILL BE BACK.
&&
.NEAR TERM /TONIGHT/...
BOTH SATELLITE OBSERVATIONS AND MODEL MOISTURE FIELDS SUPPORT PARTLY
CLOUDY TONIGHT. THIS LEAVES TEMPERATURES AS FORECAST PROBLEM.
MAV AND MET ARE CLOSE...BUT MET IS JUST SLIGHTLY COOLER. BASED ON
WHAT HAPPENED UPSTREAM LAST NIGHT I WILL USE THE MET.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
MAIN PROBLEM IS WHEN PRECIPITATION WILL DEVELOP. ALL THE MODELS
AGREE WE ONLY HAVE TO WORRY ABOUT RAIN.
NAM...AND ASSOCIATED MET...BRING IN RAIN FASTER THAN GFS AND MAV. I
GOING TO UAW THE MAV. LATEST NAM IS NOT VERY CONSISTENT WITH ITS OWN
PREVIOUS RUN...OR THE SREF. THIS SUGGESTS IT IS AN OUTLIER.
FRIDAY NIGHT AND SATURDAY ALL MODELS PUT AT LEAST SOME QPF
EVERYWHERE IN THE CWA. IN MOST PLACES WILL USE LIKELY. EXCEPTION IS
THE EXTREME NORTHEAST FRIDAY NIGHT WHERE I WILL TAKE THE RELATIVELY
LOW POPS TO A HIGH CHANCE.
MAV HAS BEEN DOING WELL WITH TEMPERATURES LATELY. WILL USE THAT
THROUGH FRIDAY NIGHT WITH LITTLE CHANGE. SATURDAY MEX HIGHS ARE
ABOVE THE GFS HIGHS FROM THE MEN. SPLIT BETWEEN MEN HIGHS AND MEN
AVERAGES LOOKS BETTER TO ME GIVEN RAIN IS FORECAST.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SAME OLD STORY AS THE MAIN CHALLENGE WITH THE EXTENDED REVOLVES
MODEL TO MODEL AND RUN TO RUN CONSISTANCY REGARDING STRENGTH AND
POSITIONING OF THE KEY SURFACE AND UPPER PLAYERS AND HENCE THEIR QPF
FIELDS. THE 00Z GFS HOWEVER IS CONTINUING THE TREND OF BEING MUCH
FASTER AND WEAKER WITH AN UPPER LOW THAT THE GFS MOVES TO EASTERN
ILLINOIS BY 12Z SUNDAY BEFORE IT GETS ABSORBED IN AN UPPER TROUGH
THAT EXTENDS SOUTHWEST FROM THE CANADIAN MARITIMES. MEANWHILE...THE
00Z GFS ENSEMBLE MEMBERS ARE NO WHERE NO CONVERGING AN ANY SURFACE
OR UPPER FEATURES AFTER SATURDAY. THE 00Z GEM AND ECMWF RUNS ARE
STRONGER AND MUCH SLOWER WITH THE AFOREMENTIONED UPPER LOW DUE TO
SHARP RIDGING ACROSS THE UPPER OHIO VALLEY. WILL LEAN TOWARDS THE
GEM AS IT IS CLOSER TO THE ECMWF BUT YET NOT QUITE AS SLOW. THIS
ALSO SEEMS TO BE WHAT THE CENTRAL INITIALIZATION IS HINTING AT AND
CLOSE TO WHAT THE HEMISPHERIC DISCUSSION IS IMPLYING.
HOWEVER...UNTIL THE MODELS SHOW SOME BETTER CONSISTANCY AND
CONVERGENCE...CONFIDENCE ON TIMING...COVERAGE AND PRECIPITATION TYPE
THIS WEEKEND AND EARLY NEXT WEEK CONTINUES TO BE ON THE LOW SIDE.
STILL...GENERAL TREND SEEMS TO BEST FIT THE 00Z GEM WHICH BRINGS A
SURFACE LOW NORTHEAST ACROSS NORTH CENTRAL INDIANA ON SUNDAY WITH
THE UPPER LOW TRAILING ACROSS ROUGHLY THE SAME PATH MONDAY MORNING
BEFORE BEING ABSORBED IN THE NORTHEASTERN TROUGH. LOOKING AT
CRITICAL THICKNESSES...IT LOOKS LIKE MOSTLY A RAIN EVENT WITH THE
BEST CHANCES SATURDAY AND SATURDAY NIGHT AND THEN BECOMING DRY BY
MONDAY. WILL HOWEVER THROUGH IN A MIX ACROSS NORTHERN COUNTIES
OVERNIGHT SATURDAY NIGHT INTO SUNDAY MORNING ACROSS OUR NORTHERN
COUNTIES AND SUNDAY NIGHT ACROSS ALL BUT THE FAR SOUTHERN COUNTIES
BASED ON FORECASTED OVERNIGHT TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 011800Z TAFS/...
CHALLENGING FORECAST WITH REGARDS TO CEILINGS THIS PERIOD AS SHALLOW
COLD ADVECTIVE CLOUD SHIELD OVER NRN INDIANA/IL HAD BEEN MOVING
SOUTHEAST AROUND 10 KTS UNTIL LAST HOUR WHEN MOVEMENT BECAME NEARLY
STATIONARY. THIS RECENT TREND IS MOST LIKELY RELATED TO GREATER
MIXING THAT HAS DEVELOPED DURING PEAK HEATING ON THE LEADING EDGE OF
THIS SHALLOW CLOUD MASS. AS DIURNAL MIXING WANES AFTER 21Z EXPECT TO
SEE CLOUD MASS MOVE SOUTH TO AT LEAST LAF/MIE AS PER 15Z RUC 950MB
RH FIELDS. GREATER UNCERTAINTY EXISTS WITH DEGREE OF LOW CLOUD
COVERAGE ACROSS REST OF TAF SITES TONIGHT. MAIN CONCERNS FOR LOW
CLOUD COVER TO MOVE INTO REST OF CENTRAL IN IS WARMER ANTECEDANT
GROUND TEMPERATURES AND WEAK CAA ABOVE THE INVERSION WHICH SHOULD
PRECLUDE ANY STRENGTHENING OF THE INVERSION OVERNIGHT. IN FACT THIS
CAA MAY ACTUALLY REDUCE THE INVERSION SUFFICIENTLY FOR THE LOW
CLOUDS TO CLEAR OUT COMPLETELY LATER THIS EVENING. ONCE MID-HIGH
CLOUD BANDS ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER KS/NE MOVE
AWAY FROM THE AREA AFTER 06Z MOSTLY CLEAR SKIES SHOULD LEAD TO THE
FORMATION OF LOWER VSBYS WITH SOME PATCHY GROUND FOG. CONF FOR FOG
IS NOT HIGH ENOUGH ATTM FOR SHOWING ANYTHING MORE THAN 1-3SM VIS AND
BR AT KLAF/KBMG AND KHUF TAFS WITH SLIGHTLY HIGHER VIS FCST AT KIND
OWING TO EFFECTS OF URBAN ENVIRONMENT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...JK
LONG TERM....MK
AVIATION...CROSBIE/TUCEK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1244 PM EST WED FEB 1 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
A COLD FRONT WILL BE EXITING THE AREA EARLY THIS MORNING...WITH
HIGH PRESSURE MOVING IN BEHIND IT. THE HIGH WILL REMAIN ACROSS THE
AREA UNTIL FRIDAY. FOR THE WEEKEND...UPPER AND SURFACE LOWS WILL
MOVE THROUGH THE REGION...BRINGING ANOTHER ROUND OF PRECIPITATION.
&&
.NEAR TERM /REST OF TODAY/...
HAVE MADE SLIGHT ADJUSTMENTS TO FORECAST. LOW CLOUD DECK PUSHING
SOUTH FROM NRN ILLLINOIS AND INDIANA WILL MOVE INTO OUR NORTHERN
COUNTIES THIS AFTERNOON ENDING ANY KIND OF WARM UP. ALSO ADJUSTED
SKIES TO BE MORE CLOUDY THERE.
FURTHER SOUTH ALONG AND SOUTH OF I-70 CORRIDOR TEMPS HAVE WARMED
NICELY ALREADY REACHING AT OR ABOVE MOS GUIDANCE FORCAST HIGHS SO
HAVE ADJUSTED TEMPS UPWARD A DEGREE OR TWO IN THESE LOCATIONS.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
FOCUS IS ON CHANCES FOR RAIN DURING THE PERIOD. STILL DISAGREEMENT
WITH HOW THE WEEKEND STORM SYSTEM WILL COME TOGETHER. THE TREND
HAS BEEN FOR A SLOWER ARRIVAL OF PRECIPITATION...SO SHIED AWAY
FROM THE FASTER NAM LATER IN THE PERIOD. OTHERWISE STUCK WITH A
BLEND.
AN UPPER WAVE WILL ALLOW A SURFACE LOW TO FORM ALONG THE FRONT TO
OUR SOUTH TONIGHT. AT THE MOMENT IT STILL APPEARS THAT THE
MOISTURE AND FORCING ASSOCIATED WITH THE LOW WILL REMAIN TO OUR
SOUTH...SO CONTINUED A DRY FORECAST TONIGHT. THE SYSTEM WILL KEEP
ENOUGH CLOUDS AROUND FOR PARTLY CLOUDY SKIES.
HIGH PRESSURE WILL THEN KEEP DRY AND MILD CONDITIONS ACROSS THE
AREA THURSDAY INTO FRIDAY...ALTHOUGH CLOUDS WILL INCREASE ON
FRIDAY AHEAD OF THE WEEKEND SYSTEM.
THAT WEEKEND SYSTEM SHOULD BE CLOSE ENOUGH FOR CHANCES OF
PRECIPITATION FRIDAY NIGHT...WITH THE HIGHEST POPS ACROSS THE
SOUTHWEST FORECAST AREA CLOSER TO THE SYSTEM. WITH THE UNCERTAINTY
AND GOING SLOWER THAN THE NAM YIELDED A FORECAST VERY SIMILAR TO
CONTINUITY WITH PREVIOUS FORECAST.
MAV MOS LOOKS PRETTY GOOD FOR TEMPERATURES THROUGH THE PERIOD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
SAME OLD STORY AS THE MAIN CHALLENGE WITH THE EXTENDED REVOLVES
MODEL TO MODEL AND RUN TO RUN CONSISTANCY REGARDING STRENGTH AND
POSITIONING OF THE KEY SURFACE AND UPPER PLAYERS AND HENCE THEIR QPF
FIELDS. THE 00Z GFS HOWEVER IS CONTINUING THE TREND OF BEING MUCH
FASTER AND WEAKER WITH AN UPPER LOW THAT THE GFS MOVES TO EASTERN
ILLINOIS BY 12Z SUNDAY BEFORE IT GETS ABSORBED IN AN UPPER TROUGH
THAT EXTENDS SOUTHWEST FROM THE CANADIAN MARITIMES. MEANWHILE...THE
00Z GFS ENSEMBLE MEMBERS ARE NO WHERE NO CONVERGING AN ANY SURFACE
OR UPPER FEATURES AFTER SATURDAY. THE 00Z GEM AND ECMWF RUNS ARE
STRONGER AND MUCH SLOWER WITH THE AFOREMENTIONED UPPER LOW DUE TO
SHARP RIDGING ACROSS THE UPPER OHIO VALLEY. WILL LEAN TOWARDS THE
GEM AS IT IS CLOSER TO THE ECMWF BUT YET NOT QUITE AS SLOW. THIS
ALSO SEEMS TO BE WHAT THE CENTRAL INITIALIZATION IS HINTING AT AND
CLOSE TO WHAT THE HEMISPHERIC DISCUSSION IS IMPLYING.
HOWEVER...UNTIL THE MODELS SHOW SOME BETTER CONSISTANCY AND
CONVERGENCE...CONFIDENCE ON TIMING...COVERAGE AND PRECIPITATION TYPE
THIS WEEKEND AND EARLY NEXT WEEK CONTINUES TO BE ON THE LOW SIDE.
STILL...GENERAL TREND SEEMS TO BEST FIT THE 00Z GEM WHICH BRINGS A
SURFACE LOW NORTHEAST ACROSS NORTH CENTRAL INDIANA ON SUNDAY WITH
THE UPPER LOW TRAILING ACROSS ROUGHLY THE SAME PATH MONDAY MORNING
BEFORE BEING ABSORBED IN THE NORTHEASTERN TROUGH. LOOKING AT
CRITICAL THICKNESSES...IT LOOKS LIKE MOSTLY A RAIN EVENT WITH THE
BEST CHANCES SATURDAY AND SATURDAY NIGHT AND THEN BECOMING DRY BY
MONDAY. WILL HOWEVER THROUGH IN A MIX ACROSS NORTHERN COUNTIES
OVERNIGHT SATURDAY NIGHT INTO SUNDAY MORNING ACROSS OUR NORTHERN
COUNTIES AND SUNDAY NIGHT ACROSS ALL BUT THE FAR SOUTHERN COUNTIES
BASED ON FORECASTED OVERNIGHT TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR 011800Z TAFS/...
CHALLENGING FORECAST WITH REGARDS TO CEILINGS THIS PERIOD AS SHALLOW
COLD ADVECTIVE CLOUD SHIELD OVER NRN INDIANA/IL HAD BEEN MOVING
SOUTHEAST AROUND 10 KTS UNTIL LAST HOUR WHEN MOVEMENT BECAME NEARLY
STATIONARY. THIS RECENT TREND IS MOST LIKELY RELATED TO GREATER
MIXING THAT HAS DEVELOPED DURING PEAK HEATING ON THE LEADING EDGE OF
THIS SHALLOW CLOUD MASS. AS DIURNAL MIXING WANES AFTER 21Z EXPECT TO
SEE CLOUD MASS MOVE SOUTH TO AT LEAST LAF/MIE AS PER 15Z RUC 950MB
RH FIELDS. GREATER UNCERTAINTY EXISTS WITH DEGREE OF LOW CLOUD
COVERAGE ACROSS REST OF TAF SITES TONIGHT. MAIN CONCERNS FOR LOW
CLOUD COVER TO MOVE INTO REST OF CENTRAL IN IS WARMER ANTECEDANT
GROUND TEMPERATURES AND WEAK CAA ABOVE THE INVERSION WHICH SHOULD
PRECLUDE ANY STRENGTHENING OF THE INVERSION OVERNIGHT. IN FACT THIS
CAA MAY ACTUALLY REDUCE THE INVERSION SUFFICIENTLY FOR THE LOW
CLOUDS TO CLEAR OUT COMPLETELY LATER THIS EVENING. ONCE MID-HIGH
CLOUD BANDS ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER KS/NE MOVE
AWAY FROM THE AREA AFTER 06Z MOSTLY CLEAR SKIES SHOULD LEAD TO THE
FORMATION OF LOWER VSBYS WITH SOME PATCHY GROUND FOG. CONF FOR FOG
IS NOT HIGH ENOUGH ATTM FOR SHOWING ANYTHING MORE THAN 1-3SM VIS AND
BR AT KLAF/KBMG AND KHUF TAFS WITH SLIGHLY HIGHER VIS FCST AT KIND
OWING TO EFFECTS OF URBAN ENVIRONMENT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...50
NEAR TERM...TUCEK
SHORT TERM...50
LONG TERM....MK
AVIATION...CROSBIE/TUCEK
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1239 PM EST WED FEB 1 2012
.AVIATION...
SHALLOW MOIST LAYER FROM SFC-1200FT TRAPPED BENEATH A STRONG
INVERSION OVER THE REGION AS EVIDENCED BY NEARBY MORNING UPPER
AIR SOUNDINGS AND TAMDAR. LATEST VISIBLE SATELLITE IMAGERY
INDICATES STRATUS SEWD PROGRESS SLOWING JUST SOUTH OF FWA AND SOME
HOLES DEVELOPING UPSTREAM OVER WI/NE IL. GIVEN WK FLOW AND
EXTENT OF CLOUD SHIELD UPSTREAM...CONTD WITH BKN MVFR CIGS IN THE TAFS
UNTIL THIS EVE... THOUGH CONFIDENCE ON WHEN LOW CLOUDS WILL BREAK
OUT AT THE TERMINALS IS NOT HIGH ATTM. MOIST LOW LEVELS AND LIGHT
WINDS SHOULD PERSIST OVERNIGHT SO EXPECT SOME RADIATIONAL COOLING
FOG TO DEVELOP TOWARD DAYBREAK THURSDAY LOWERING VISIBILITY INTO
MVFR RANGE.
&&
.PREV DISCUSSION... /ISSUED 1047 AM EST WED FEB 1 2012/
UPDATE...
LARGE AREA OF STRATUS OVER THE UPR GRTLKS CONTG TO SAG SEWD ACROSS
OUR CWA THIS MORNING. USING RUC 925MB RH FIELDS AND LATEST VISIBLE
SATELLITE IMAGERY EXPECT THIS CLOUD DECK WILL IMPACT OUR ENTIRE CWA
THIS AFTN... THUS UPDATED FCST TO INCREASE CORRESPONDING CLOUD COVER GRIDS.
STRATUS SHOULD HOLD TEMPS DOWN A BIT THIS AFTN AND LOWERED HIGHS
SLIGHTLY MOST OF THE CWA. CLOUDS COULD LIMIT COOLING TONIGHT AS
WELL BUT HELD OFF MAKING ANY CHANGES IN THAT REGARD ATTM.
SHORT TERM...
TODAY THROUGH THURSDAY NIGHT
SFC COLD FRONT AND THE ASSOCIATED MID LEVEL IMPULSE WILL CONTINUE TO
EXIT THE REGION WITH COOLER AIR ADVECTING INTO THE REGION. FAIRLY
QUIET WEATHER IN THE PERIOD...WITH CONTINUED PROGRESSIVE FLOW AND A
DEVELOPING SPLIT PER A DIGGING SW CONUS TROUGH. ANOTHER FAST MOVING
NORTHERN STREAM WAVE EXPECTED INTO THE GREAT LAKES TONIGHT...WITH
WEAK RIDGING AT THE SFC. MILD THERMAL FIELDS PER PAC ORIGIN FLOW
WILL SUPPORT TEMPS ABOVE NORMAL IN THE PERIOD...WITH COOLER
CONDITIONS TODAY ON THE BACKSIDE OF THE DEPARTING IMPULSE. MAIN
CONCERN TODAY WILL BE HIGH TEMPS ACROSS THE NORTHERN THIRD AS
BACKSIDE IMPULSE STRATUS GRAZES THE AREA. GENERAL CONSENSUS IN
GUIDANCE IS FOR THE BULK OF THE CLOUDS TO REMAIN NORTH OF THE
FA...WITH THE NORTHERN THIRD BEING GRAZED THIS MORNING. DIURNAL
MIXING SHOULD SUPPORT SCATTERING OF THE STRATO CU DECK BY LATE
MORNING/EARLY AFTERNOON. HIGHS WILL BE COOLER THAN YESTERDAY...WITH
MOST AREAS ONLY SEEING 40S...SOME LOWER 50S POSSIBLE FAR SOUTH.
NORTHERN PLAINS IMPULSE /EVIDENT IN WATER VAPOR/ WILL ADVECT INTO
THE GREAT LAKES OVERNIGHT...SUPPORTING INCREASED MID/HIGH CLOUD.
OVERALL WEAK FORCING WITH LIMITED LL MOISTURE WILL SUPPORT LIGHT LL
FLOW...WITH DRY CONDITIONS OVERNIGHT. INCREASED CLOUD COVER WILL
KEEP TEMPS UP SOME...WITH LOWER 30S TO UPPER 20S EXPECTED. SMALL
THERMAL FIELD UNDULATION ASSOCIATED WITH THIS WAVE WILL SUPPORT A
REINFORCEMENT OF THERMAL FIELDS WITH HIGHS GENERALLY AROUND TODAY/S
VALUES...SLIGHTLY WARMER SW HALF GIVEN ENSUING WAA BY LATER IN THE
DAY PERIOD THUR. MOSTLY CLEAR SKIES AND LIGHT WINDS EXPECTED THUR
NIGHT...WITH MODERATE RADIATIONAL COOLING SUPPORTING LOWS IN THE
UPPER 20S MOST PLACES. A FEW HEIGHT RISE CIRRUS ARE POSSIBLE.
LONG TERM...
COMPLICATED AND VARIABLE LONG TERM FORECAST AS MODELS REMAIN IN FLUX
WITH HANDLING WEEKEND SYSTEM OVER CENTRAL CONUS. PREFERENCE AT THIS
TIME LIES TOWARD THE ECMWF WITH STRONG WEIGHT TOWARD CONSISTENCY AS
DETAILS AND EVEN LARGER SCALE FLOW STILL IN QUESTION WITH UPCOMING
SYSTEM. WHAT DOES LOOK MORE CERTAIN ARE TEMPERATURES THROUGH MOST OF
THIS LONG TERM PERIOD REMAINING ABOVE NORMAL. THERE ARE SIGNS
POINTING TOWARD COLDER...MORE SEASONABLE TEMPERATURES JUST BEYOND
THE DAY 7 PERIOD.
WATER VAPOR TELLS THE STORY TODAY WITH STRONG NORTH PACIFIC JET AND
SEVERAL STRONG SHORT WAVES BEGINNING TO BUCKLE THE FLOW OVER THE
NORTH PACIFIC. PNA TELECONNECTIONS SHOW TREND TOWARD POSITIVE PHASE
FROM 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL WITH GOOD CORRELATION
THROUGH THE 7 TO 10 DAY FORECAST PERIOD. AO INDICES ALSO TRENDING
STRONGLY NEGATIVE SUPPORTING GREATER AMPLIFICATION OF UPSTREAM
PATTERN AND POTENTIAL COLDER TEMPERATURES MID TO END OF NEXT WEEK.
THESE FACTORS SHOULD ALLOW FOR STRONG RIDGE TO DEVELOP IN WESTERN
CONUS WHICH WOULD ALSO ALLOW INCOMING ENERGY TO DEEPEN ACROSS THE
PLAINS BY END OF THIS WEEK. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON
THIS SCENARIO THROUGH FRIDAY WITH CLOSED LOW DEVELOPING IN CENTRAL
CONUS. MODELS REALLY BEGIN TO DIVERGE THIS WEEKEND WITH HOW THIS LOW
WILL EVOLVE AND EVENTUALLY EJECT OUT OF CENTRAL CONUS AND THE
ASSOCIATED IMPACTS AND TIMING FOR OUR AREA. DIFFERENCES APPEAR TO BE
RELATED TO TIMING OF A NORTHERN STREAM SHORT WAVE AND LOCATION OF
UPPER LOW BY END OF WEEKEND. GFS AS EXPECTED IS FARTHER EAST WITH
UPPER LOW AND ALLOWS NORTHERN WAVE TO PICK UP CLOSED LOW AND BOTH
EJECT SOUTHEAST OUT OF THE AREA SUNDAY NIGHT. MEANWHILE...ECMWF
SOLUTION APPEARS TO BE SLOWER WITH UPPER LOW DRIFTING EAST AND
ALLOWS NORTHERN STREAM WAVE TO PASS THROUGH GREAT LAKES LEAVING
BEHIND THE LOW IN THE PLAINS TO CONTINUE WITH A SLOWER MOVEMENT
NORTHEAST. GIVEN TYPICAL GFS BIAS WITH BEING TOO FAR EAST WITH
CLOSED UPPER LOWS AND ECMWF SUPERIOR PERFORMANCE DURING THE WINTER
PREFERENCE LIES TOWARD THE ECMWF. HOWEVER...FOR CONSISTENCY AND TO
AVOID FLIP FLOPPING FORECAST DUE TO HIGH UNCERTAINTY...HAVE REMAINED
FAIRLY CLOSE TO ALL BLEND INIT FOR THIS PACKAGE. THIS REFLECTS BEST
CHANCES FOR PCPN LATE FRIDAY NIGHT AND SATURDAY IN SOUTH AS INITIAL
SURGE OF MOISTURE AND WEAK SHORT WAVE APPROACH THE AREA. LOW CHANCE
POPS CONTINUED THROUGH SUNDAY WITH ECMWF SHOWING WEAK LIFT AND
MOISTURE FOR POSSIBLE SHOWERS. REMAINDER OF FORECAST WAS LEFT
UNCHANGED WITH NO APPRECIABLE WEATHER MENTION GIVEN HIGH UNCERTAINTY
AND LOW PROBABILITY AT THIS TIME.
REGARDLESS OF SOLUTIONS TEMPERATURES WILL REMAIN ABOVE NORMAL
THROUGH MOST OF THE PERIOD...AND WELL ABOVE NORMAL THROUGH THIS
WEEKEND. TEMPERATURES LIKELY TO TREND BACK CLOSER TO NORMAL BY DAY 7
WITH ECMWF SOLUTION. MUCH COLDER AIR LOOKS TO STAGE TO OUR NORTH BY
DAY 7 WITH POSSIBILITY OF REACHING US BY MID TO LATE NEXT WEEK.
TELECONNECTION INDICES FAVORING THIS BUT NORTH ATLANTIC OSCILLATION
FORECAST CONTINUES TO BE NEAR NEUTRAL THROUGH THE WEEK 2 PERIOD
SUGGESTING NO BLOCKING DOWNSTREAM TO HOLD COLD AIR IN PLACE. THIS IS
WELL OUTSIDE THE CURRENT FORECAST PERIOD BUT SOMETHING TO WATCH
GIVEN POSITIVE PNA AND NEGATIVE AO TRENDS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...LASHLEY
AVIATION...JT
AREA FORECAST DISCUSSION
NWS NORTHERN INDIANA
1047 AM EST WED FEB 1 2012
.UPDATE...
LARGE AREA OF STRATUS OVER THE UPR GRTLKS CONTG TO SAG SEWD ACROSS
OUR CWA THIS MORNING. USING RUC 925MB RH FIELDS AND LATEST VISIBLE
SATELLITE IMAGERY EXPECT THIS CLOUD DECK WILL IMPACT OUR ENTIRE CWA
THIS AFTN... THUS UPDATED FCST TO INCREASE CORRESPONDING CLOUD COVER GRIDS.
STRATUS SHOULD HOLD TEMPS DOWN A BIT THIS AFTN AND LOWERED HIGHS
SLIGHTLY MOST OF THE CWA. CLOUDS COULD LIMIT COOLING TONIGHT AS
WELL BUT HELD OFF MAKING ANY CHANGES IN THAT REGARD ATTM.
&&
.PREV DISCUSSION... /ISSUED 640 AM EST WED FEB 1 2012/
AVIATION.../12Z TAFS/
AN AREA OF MVFR CIGS OVER LAKE MICHIGAN WILL MOVE INTO KSBN SHORTLY
AFTER TAF ISSUANCE. A FEW POCKETS OF MVFR STRATUS HAVE DEVELOPED
AHEAD OF THE MAIN AREA AND MAY IMPACT KFWA EARLY THIS MORNING.
OTHERWISE...KFWA STILL LOOKS TO REMAIN ON SOUTHERN FRINGE OF MAIN
CLOUD DECK. VFR CONDITIONS EXPECTED ALL PLACES BY AFTERNOON.
SHORT TERM...
TODAY THROUGH THURSDAY NIGHT
SFC COLD FRONT AND THE ASSOCIATED MID LEVEL IMPULSE WILL CONTINUE TO
EXIT THE REGION WITH COOLER AIR ADVECTING INTO THE REGION. FAIRLY
QUIET WEATHER IN THE PERIOD...WITH CONTINUED PROGRESSIVE FLOW AND A
DEVELOPING SPLIT PER A DIGGING SW CONUS TROUGH. ANOTHER FAST MOVING
NORTHERN STREAM WAVE EXPECTED INTO THE GREAT LAKES TONIGHT...WITH
WEAK RIDGING AT THE SFC. MILD THERMAL FIELDS PER PAC ORIGIN FLOW
WILL SUPPORT TEMPS ABOVE NORMAL IN THE PERIOD...WITH COOLER
CONDITIONS TODAY ON THE BACKSIDE OF THE DEPARTING IMPULSE. MAIN
CONCERN TODAY WILL BE HIGH TEMPS ACROSS THE NORTHERN THIRD AS
BACKSIDE IMPULSE STRATUS GRAZES THE AREA. GENERAL CONSENSUS IN
GUIDANCE IS FOR THE BULK OF THE CLOUDS TO REMAIN NORTH OF THE
FA...WITH THE NORTHERN THIRD BEING GRAZED THIS MORNING. DIURNAL
MIXING SHOULD SUPPORT SCATTERING OF THE STRATO CU DECK BY LATE
MORNING/EARLY AFTERNOON. HIGHS WILL BE COOLER THAN YESTERDAY...WITH
MOST AREAS ONLY SEEING 40S...SOME LOWER 50S POSSIBLE FAR SOUTH.
NORTHERN PLAINS IMPULSE /EVIDENT IN WATER VAPOR/ WILL ADVECT INTO
THE GREAT LAKES OVERNIGHT...SUPPORTING INCREASED MID/HIGH CLOUD.
OVERALL WEAK FORCING WITH LIMITED LL MOISTURE WILL SUPPORT LIGHT LL
FLOW...WITH DRY CONDITIONS OVERNIGHT. INCREASED CLOUD COVER WILL
KEEP TEMPS UP SOME...WITH LOWER 30S TO UPPER 20S EXPECTED. SMALL
THERMAL FIELD UNDULATION ASSOCIATED WITH THIS WAVE WILL SUPPORT A
REINFORCEMENT OF THERMAL FIELDS WITH HIGHS GENERALLY AROUND TODAY/S
VALUES...SLIGHTLY WARMER SW HALF GIVEN ENSUING WAA BY LATER IN THE
DAY PERIOD THUR. MOSTLY CLEAR SKIES AND LIGHT WINDS EXPECTED THUR
NIGHT...WITH MODERATE RADIATIONAL COOLING SUPPORTING LOWS IN THE
UPPER 20S MOST PLACES. A FEW HEIGHT RISE CIRRUS ARE POSSIBLE.
LONG TERM...
COMPLICATED AND VARIABLE LONG TERM FORECAST AS MODELS REMAIN IN FLUX
WITH HANDLING WEEKEND SYSTEM OVER CENTRAL CONUS. PREFERENCE AT THIS
TIME LIES TOWARD THE ECMWF WITH STRONG WEIGHT TOWARD CONSISTENCY AS
DETAILS AND EVEN LARGER SCALE FLOW STILL IN QUESTION WITH UPCOMING
SYSTEM. WHAT DOES LOOK MORE CERTAIN ARE TEMPERATURES THROUGH MOST OF
THIS LONG TERM PERIOD REMAINING ABOVE NORMAL. THERE ARE SIGNS
POINTING TOWARD COLDER...MORE SEASONABLE TEMPERATURES JUST BEYOND
THE DAY 7 PERIOD.
WATER VAPOR TELLS THE STORY TODAY WITH STRONG NORTH PACIFIC JET AND
SEVERAL STRONG SHORT WAVES BEGINNING TO BUCKLE THE FLOW OVER THE
NORTH PACIFIC. PNA TELECONNECTIONS SHOW TREND TOWARD POSITIVE PHASE
FROM 1 TO 2 STANDARD DEVIATIONS ABOVE NORMAL WITH GOOD CORRELATION
THROUGH THE 7 TO 10 DAY FORECAST PERIOD. AO INDICES ALSO TRENDING
STRONGLY NEGATIVE SUPPORTING GREATER AMPLIFICATION OF UPSTREAM
PATTERN AND POTENTIAL COLDER TEMPERATURES MID TO END OF NEXT WEEK.
THESE FACTORS SHOULD ALLOW FOR STRONG RIDGE TO DEVELOP IN WESTERN
CONUS WHICH WOULD ALSO ALLOW INCOMING ENERGY TO DEEPEN ACROSS THE
PLAINS BY END OF THIS WEEK. MEDIUM RANGE MODELS IN GOOD AGREEMENT ON
THIS SCENARIO THROUGH FRIDAY WITH CLOSED LOW DEVELOPING IN CENTRAL
CONUS. MODELS REALLY BEGIN TO DIVERGE THIS WEEKEND WITH HOW THIS LOW
WILL EVOLVE AND EVENTUALLY EJECT OUT OF CENTRAL CONUS AND THE
ASSOCIATED IMPACTS AND TIMING FOR OUR AREA. DIFFERENCES APPEAR TO BE
RELATED TO TIMING OF A NORTHERN STREAM SHORT WAVE AND LOCATION OF
UPPER LOW BY END OF WEEKEND. GFS AS EXPECTED IS FARTHER EAST WITH
UPPER LOW AND ALLOWS NORTHERN WAVE TO PICK UP CLOSED LOW AND BOTH
EJECT SOUTHEAST OUT OF THE AREA SUNDAY NIGHT. MEANWHILE...ECMWF
SOLUTION APPEARS TO BE SLOWER WITH UPPER LOW DRIFTING EAST AND
ALLOWS NORTHERN STREAM WAVE TO PASS THROUGH GREAT LAKES LEAVING
BEHIND THE LOW IN THE PLAINS TO CONTINUE WITH A SLOWER MOVEMENT
NORTHEAST. GIVEN TYPICAL GFS BIAS WITH BEING TOO FAR EAST WITH
CLOSED UPPER LOWS AND ECMWF SUPERIOR PERFORMANCE DURING THE WINTER
PREFERENCE LIES TOWARD THE ECMWF. HOWEVER...FOR CONSISTENCY AND TO
AVOID FLIP FLOPPING FORECAST DUE TO HIGH UNCERTAINTY...HAVE REMAINED
FAIRLY CLOSE TO ALL BLEND INIT FOR THIS PACKAGE. THIS REFLECTS BEST
CHANCES FOR PCPN LATE FRIDAY NIGHT AND SATURDAY IN SOUTH AS INITIAL
SURGE OF MOISTURE AND WEAK SHORT WAVE APPROACH THE AREA. LOW CHANCE
POPS CONTINUED THROUGH SUNDAY WITH ECMWF SHOWING WEAK LIFT AND
MOISTURE FOR POSSIBLE SHOWERS. REMAINDER OF FORECAST WAS LEFT
UNCHANGED WITH NO APPRECIABLE WEATHER MENTION GIVEN HIGH UNCERTAINTY
AND LOW PROBABILITY AT THIS TIME.
REGARDLESS OF SOLUTIONS TEMPERATURES WILL REMAIN ABOVE NORMAL
THROUGH MOST OF THE PERIOD...AND WELL ABOVE NORMAL THROUGH THIS
WEEKEND. TEMPERATURES LIKELY TO TREND BACK CLOSER TO NORMAL BY DAY 7
WITH ECMWF SOLUTION. MUCH COLDER AIR LOOKS TO STAGE TO OUR NORTH BY
DAY 7 WITH POSSIBILITY OF REACHING US BY MID TO LATE NEXT WEEK.
TELECONNECTION INDICES FAVORING THIS BUT NORTH ATLANTIC OSCILLATION
FORECAST CONTINUES TO BE NEAR NEUTRAL THROUGH THE WEEK 2 PERIOD
SUGGESTING NO BLOCKING DOWNSTREAM TO HOLD COLD AIR IN PLACE. THIS IS
WELL OUTSIDE THE CURRENT FORECAST PERIOD BUT SOMETHING TO WATCH
GIVEN POSITIVE PNA AND NEGATIVE AO TRENDS.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SHORT TERM...JC
LONG TERM...LASHLEY
AVIATION...JC
UPDATE...TAYLOR
AREA FORECAST DISCUSSION
NWS DES MOINES IA
537 PM CST THU FEB 2 2012
...UPDATED FOR 00Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
COMPLICATED FORECAST TONIGHT ALBEIT A DRY ONE. FOG WAS SLOW TO BURN
OFF TODAY ACROSS THE NORTHEAST AND MOISTURE REMAINS JUST TO OUR
EAST. LOW LEVEL FLOW TONIGHT WILL BECOME EASTERLY AND ADVECT THE
MOISTURE/FOG BACK INTO THE AREA. I AM EXPECTING SIMILAR AREAS TO
HAVE DENSE FOG TONIGHT INTO FRIDAY MORNING AS WE DID LAST NIGHT.
THE QUESTION IS ONE OF TIMING AND EXTENT OF THE DENSE FOG. HRRR HAD
A DECENT HANDLE ON THE REDUCED VISIBILITIES BUT LIKE THIS MORNING...
IT WAS A BIT OVERDONE ON EXTENT. I USED TIMING SIMILAR TO THE HRRR
BUT EXTENT SIMILAR TO LAST NIGHT. TIME/HEIGHT CROSS SECTIONS
INDICATE DRY AIR JUST OFF THE SURFACE SO MOISTURE WON`T GET DEEP
ENOUGH TO PRODUCE PRECIP. WE ALSO DON`T HAVE ANY LIFT TO SPEAK OF
UNTIL FRIDAY MORNING. TONIGHTS LOW TEMPS WERE KEPT SIMILAR TO LAST
NIGHT.
.LONG TERM /FRIDAY THROUGH FRIDAY/...
COMPLICATED WEATHER SITUATION WITH THE LOW COMING OUT OF THE
ROCKIES. IN THE LONG WAVE PATTERN THE MEAN RIDGE POSITION IS IN THE
110W TO 115W AREA WITH THE MEAN TROUGH TO THE EAST IN THE 70W AREA.
LOW COMING OUT OF THE ROCKIES LIFTS NORTHEAST THEN TAKES A TURN TO
THE EAST AND EVENTUALLY EAST-SOUTHEAST AS IT MOVES PAST THE MEAN
RIDGE POSITION. THIS LENDS CREDIBILITY TO THE SOUTHWARD SHIFT IN
THE MODELS AND ALSO THE RAPID WEAKENING AS THE SYSTEM MOVES EAST.
THE SNOWFALL MAY WELL LOOK SOMEWHAT SIMILAR TO THE STORM SYSTEM A
FEW WEEKS BACK THAT DROPPED THE HEAVY SNOWFALL IN KS. A COUPLE
ANALOG CASES STAND OUT TODAY WITH ONE BEING THE EVENT AROUND 21 JAN
1990...THOUGH SHIFTED A WAYS FARTHER SOUTH...THE OTHER THE EVENT
AROUND 22 MAR 2006. IN BOTH CASES THE SYSTEM WEAKENED AS IT MOVED
EAST WITH MUCH OF THE HEAVY SNOW REMAINING WEST OF THE MO RIVER.
SEE A SIMILAR SITUATION HERE. INITIALLY DRY LOW LEVEL AIR WILL
INHIBIT PRECIP DEVELOPMENT. THE UPPER LOW AND STRONG DYNAMICS WILL
OVERCOME THAT WITH THE COLUMN SATURATING OVER THE CENTRAL AND SOUTH
BY FRI EVENING. PRECIPITATION WILL INITIALLY FALL AS RAIN WITH A
VERY GRADUAL CHANGE TO SNOW AS COLD AIR DEVELOPS AROUND THE CLOSED
LOW. SOME SLEET IS ALSO POSSIBLE ALONG THE NORTH EDGE OF THE PRECIP
AREA EARLY ON DUE TO A DECENT WARM LAYER...BUT EVAPORATIONAL COOLING
MAKING UP THE DIFFERENCE RESULTING IN RE-FREEZE. LOW WILL PULL TO
THE EAST SAT NIGHT WITH LAST OF THE SNOW ENDING ON SUN. BACKED OFF
A BIT ON THE WINTER STORM WATCH DUE TO UNANIMOUS SHIFT IN THE
MODELS. THINKING AT THIS POINT IS IF WINTER WINTER STORM CONDITIONS
ARE TO BE MET...IT WILL BE A MARGINAL CASE AND CURRENT ADJUSTMENTS
TO THE WATCH AREA INCLUDE ABOUT A COUNTY BUFFER TO AREA LIKELY TO
REACH CRITERIA. WINDS ARE NOT LIKELY TO BE A MAJOR FACTOR WITH THIS
SYSTEM...THOUGH MAY GUST TO 25 TO 30 MPH AT TIMES. BLOWING SNOW
WILL BE LIMITED BY THE SPRING TYPE NATURE OF THE SYSTEM. NO
SIGNIFICANT COOLING BEHIND THE STORM SYSTEM AS THE AIRMASS IS
PACIFIC IN NATURE. ARCTIC AIR IS EXPECTED TO REMAIN WELL TO THE
NORTHEAST OF IA. DRY WEATHER AS WE HEAD INTO NEXT WEEK WITH TEMPS
REMAINING ABOVE NORMAL BY A FEW DEGREES.
&&
.AVIATION...03/00Z
MAIN ISSUE WILL BE WITH LIFR CONDITIONS IN DENSE FOG AND LOW
CEILINGS IN FAR EASTERN PORTIONS OF THE FORECAST AREA AFFECTING KALO
AND THE POSSIBILITY AT KMCW AND KOTM AS WELL. MAIN CONCERN IS THE
THICKNESS OF CIRRUS AND IF IT WILL PREVENT ADDITIONAL DEVELOPMENT OF
THE FOG OVERNIGHT. HAVE RECENTLY SEEN VISIBILITIES PLUMMET AT KALO
AND NEARBY SITES WITH THE LOSS OF DAYTIME HEATING. WILL LIKELY SEE
SOME EXPANSION DURING THE NIGHT ONCE AGAIN ALTHOUGH NOT SURE THE
EXTENT WILL BE AS GREAT. KFOD AND KDSM LIKELY TO REMAIN GENERALLY
VFR FOR MUCH OF THE TAF PERIOD ALTHOUGH VFR CEILINGS WILL LOWER
THROUGH THE DAY ON FRIDAY AS A STORM SYSTEM APPROACHES FROM THE
SOUTHWEST AND LIFT INCREASES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM FRIDAY EVENING THROUGH LATE SATURDAY
NIGHT FOR ADAIR-ADAMS-AUDUBON-CARROLL-CASS-CRAWFORD-DALLAS-
GREENE-GUTHRIE-MADISON-TAYLOR-UNION.
DENSE FOG ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM CST FRIDAY FOR
DAVIS-JASPER-MAHASKA-MARION-MARSHALL-MONROE-POWESHIEK-TAMA-
WAPELLO.
DENSE FOG ADVISORY FROM 9 PM THIS EVENING TO 10 AM CST FRIDAY
FOR BLACK HAWK-BREMER-BUTLER-CERRO GORDO-FRANKLIN-GRUNDY-HANCOCK-
HARDIN-WINNEBAGO-WORTH.
&&
$$
SHORT TERM...FAB
LONG TERM...MS FEB 12
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1210 PM CST WED FEB 1 2012
.AVIATION...
STRATUS AND FOG WITH AREAS OF DENSE FOG AND IFR TO VLIFR CONDITIONS
CONTINUE TO BLANKET THE KCID... KDBQ AND KMLI TERMINALS AND HOLDING
JUST NORTH OF KBRL. WITH TRAPPING LLVL INVERSION AND LITTLE
SENSIBLE MIXING WIND WILL EXTEND THESE CONDITIONS INTO THE EVENING.
SOME BRIEF WEST NORTHWEST BOUNDARY LAYER WIND PICK UP LATE
AFTERNOON INTO EARLY EVENING MAY TRY AND IMPROVE CIGS ABOVE
500-1000 FT AGL AND VSBYS TO 2-4SM AT CID AND MLI...BUT CONFIDENCE
ON THIS REMAIN LOWS AND MAY BE OPTIMISTIC THINKING. FEEL AREAS
WHERE STRATUS IS CURRENTLY ONGOING WILL LOWER INTO THE 1/2 TO
1/4SM VSBYS AGAIN TONIGHT BY 03Z AT MOST SITES WITH CIGS/VVS UNDER
500 FT AGL UNDER SLOW MOVING RIDGE. THAT/S IF EVEN THE SITES
IMPROVE LATER THIS AFTERNOON. EVEN IN AREAS THAT CLEAR OR IF BRL
REMAINS CLEAR THIS AFTERNOON AND EVENING...THESE AREAS MAY
RADIATIONALLY FOG BACK IN BY 05Z-06Z AT THE LATEST. HOPEFULLY EAST-
SOUTHEAST RETURN FLOW AFTER PASSING SFC RIDGE AXIS WILL BEGIN TO
MIX OUT ANY LINGERING FOG AND VERY LOW CLOUDS BY 15Z THU MORNING.
..12..
&&
.PREV DISCUSSION... /ISSUED 608 AM CST WED FEB 1 2012/
UPDATE...
STRATUS AND FOG CONTINUES TO ADVECT IN ON LLVL NORTHWEST FLOW. SEVERAL
SITES HAVE GONE DOWN AT OR BELOW 1/4SM ESPECIALLY ON THE IA SIDE
OF RIVER ALONG/N OF I-80. HAVE THEREFORE ISSUED DENSE FOG ADVISORY FOR
THIS AREA UNTIL 16Z. GIVEN STRENGTH OF INVERSION AND STRATUS COULD SEE
DENSE FOG PERSIST INTO THE AFTN.
PREV DISCUSSION... /ISSUED 320 AM CST WED FEB 1 2012/
SYNOPSIS...
EARLY AM SFC ANALYSIS PLACES LOW NORTH OF LAKE HURON JUST TO NORTH OF
SUDBURY ONTARIO. COLD FRONT TRAILS FROM THE LOW THROUGH CENTRAL IN
INTO NORTH TX. WEAK RIDGING EXTENDS FROM CENTRAL PLAINS INTO THE
UPPER MIDWEST. STRATUS WHICH FORMED OVER THE DAKOTAS INTO WESTERN MN
YSTDY CONTINUES TO EXPAND AND SURGE SOUTHEAST AIDED BY COLD
ADVECTION OVER EXISTING SNOWPACK NORTH AND MOIST BL FROM SNOW MELT.
LATEST 11-3.9 MICRON SATL IMAGERY SHOWS LEADING EDGE OF THE STRATUS
FROM KVTI TO KFEP MOVING SOUTHEAST AT AROUND 12 KTS. SOME FOG ALSO
OCCURRING WITH STRATUS... BUT VSBYS GENERALLY AT OR ABOVE 3SM ATTIM.
SHORT TERM...TODAY AND TONIGHT...
CLOUD TRENDS WITH IMPACT ON TEMPS... AND FOG POTENTIAL MAIN FCST
CONCERNS.
MOST MODELS STRUGGLING TO CAPTURE CURRENT STRATUS DECK... EXCEPT
FOR LATEST RUNS OF HRRR AND RUC BACKUP MODELS VIA ESRL. THESE
MODELS GENERALLY SUPPORT CONTINUED SOUTHEAST MOVEMENT THROUGH
DAYBREAK WITH MOST OF AREA NORTH OF HWY 34 BLANKETED BY THE STRATUS
BY MID AM. ONE CONCERN IS THAT RECENT SATL TRENDS SEEM TO SHOW THE
STRATUS CONTINUING TO SLOW... AND MAY BE DUE IN PART TO OUTRUNNING
THE SNOW FIELD AND MORE MOIST BL FROM SNOW MELT PAST 24 HRS NORTH OF
HWY 30. JUST WHERE LEADING EDGE OF STRATUS RESIDES BY MID AM
LIKELY TO BE IT FOR MOVEMENT AS STRENGTHENING SOLAR INSOLATION
LIKELY TO IMPEDE FURTHER PROGRESS. OF COURSE WHERE THIS ENDS UP WILL
BE HUGE FACTOR ON HIGH TEMPS. ANOTHER FACTOR IS EVOLUTION OF THE
EXISTING STRATUS THIS AFTN INTO TNGT AND WHETHER ANY CLEARING CAN
TAKE PLACE. LATEST HRRR AND RUC BACKUP MODELS DO SUPPORT DECREASE IN
STRATUS THIS AFTN... WITH HRRR SLIGHTLY SLOWER AND NOT UNTIL MID AFTN.
0412Z AMDAR ASCENT SOUNDING FROM KMSP SIMILAR TO 00Z MPX RAOB AND
SHOWS MOIST LAYER 500-1000 FT THICK... WITH MOISTURE LINGERING INTO
STRONG INVERSION AND NOT JUST BELOW IT. THIS IS A CONCERN AS IS FACT
THAT AREA WILL RESIDE IN WEAK SYNOPTIC SCALE FLOW... THUS MIXING WILL
BE LIMITED TO TAP DRY AIR ALOFT AND PROMOTE EROSION. THEREFORE
FAVOR SLOWER CLEARING TRENDS FROM HRRR... BUT ALSO MUST WONDER IF THE
STRATUS DOESNT DISSIPATE THIS AFTN WHAT WOULD PROMOTE EVACUATION TNGT.
SOME MODELS DO SHOW WARMING IN 925 MB LAYER TNGT AS FLOW IN THIS
LAYER BECOMES WESTERLY IN ASSOCIATION WITH CLIPPER TYPE SYSTEM PASSING
WELL NORTH INTO NORTHERN MN AND WI. THIS MAY BE ENOUGH TO CHEW AWAY AT
ANY RESIDUAL STRATUS... AND FOR NOW SKY COVER GRIDS EVOLVING TO MORE
OPTIMISTIC IN TIME. AS FOR TDY... WILL BE HEAVILY NOWCASTING CURRENT
STRATUS DECK AND USING HRRR AND RUC BACKUP MODELS FOR TRENDS. FOR NOW
WILL GO WITH IDEA OF STRATUS NEARING HWY 34 BY MID AM THEN LINGERING
INTO AFTN WITH SLOW EROSION THROUGH THIS EVE. ALL AREAS TDY WILL BE
COOLER... BUT TEMPS STILL ABOVE NORMAL. COOLEST READINGS BENEATH THE
STRATUS WHERE TEMPS COULD STRUGGLE TO 40 DEGS IF THEY HOLD ALL DAY.
OTRW... WARMEST READINGS SOUTH WHERE U40S TO L50S LOOK LIKELY WITH SOME
INCREASING HIGH CLOUDINESS. IN SHORT... AS CLOUDS GO... SO GO THE TEMPS.
WITH SOME UNCERTAINTY ON CLOUD TRENDS TNGT STAYED NEAR GUIDANCE BLEND
ON LOW TEMPS. FOG A POSSIBILITY TNGT WITH LIGHT BL FLOW AND LLVL MOISTURE
ESPECIALLY IN THOSE AREAS THAT SEE CLEARING LATE DAY INTO EARLY EVE.
IF STRATUS LINGERS WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG FORM ON
WESTERN EDGE. TOO UNCERTAIN THOUGH FOR ANY MENTION ATTIM BUT PASS ON THE
CONCERN TO DAY CREW. ..05..
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
DRY AND QUIET CONDITIONS WILL BE SEEN THURS/THURS NIGHT AS HIGH
PRESSURE MOVES ACROSS THE AREA. TEMPERATURES WILL CONTINUE TO
AVERAGE ABOVE NORMAL.
STARTING FRIDAY...THINGS BECOME MORE INTERESTING. DPROG/DT CONTINUES
TO SHOW A SUBTLE SLOWING OF THE RESPECTIVE MODEL SOLUTIONS. HIGH
PRESSURE FROM THE NORTHERN PLAINS INTO THE GREAT LAKES CONTINUES TO
TREND STRONGER INDICATING A DEEPER FETCH OF DRY EASTERLY FLOW. THE
MAJOR UNKNOWN IS THE ENERGY CURRENTLY ENTERING THE GULF OF ALASKA
AND HOW IT WILL KICK OUT THE CUT OFF LOW IN THE PLAINS. ALL MODELS
CONTINUE TO SHOW VARIABILITY WHICH IS TRACEABLE TO HOW THE
RESPECTIVE ENERGIES INTERACT WITH EACH OTHER.
SO...FRIDAY MORNING WILL BE DRY WITH INCREASING CLOUDS. ALL MODELS
SHOW STRONG FORCING AND LOW CONDENSATION PRESSURE DEFICITS FROM
MISSOURI INTO CENTRAL IOWA ALONG WITH A GOOD MOISTURE FEED. OVER THE
CWFA...ALL MODELS SHOW EASTERLY FLOW FROM THE SFC UP THROUGH 850MB.
THUS PRECIP WILL NOT BE FAR AWAY FROM THE FAR SOUTHWEST PART OF THE
CWFA BY MID DAY FRIDAY.
FRIDAY AFTERNOON...THE DEEP AND DRY EASTERLY FLOW CONTINUES ACROSS
THE CWFA. BY MID TO LATE AFTERNOON 850-700MB CONDENSATION PRESSURE
DEFICITS COLLAPSE OVER ROUGHLY THE SOUTHWEST QUARTER OF THE CWFA
WITH GOOD FORCING. THE MOISTURE FEED BEGINS MOVING INTO THE CWFA AS
WELL. THE HEAVY RAIN AND LIFT TOOLS SHOW THE STRONG CONVERGENCE IS
THERE BUT WEAKENING WITH TIME. THUS RAIN SHOULD DEVELOP/MOVE INTO
THE CWFA IN AN ARCING LINE FROM NORTHERN KEOKUK COUNTY TO ROUGHLY
THE HANCOCK/MCDONOUGH BORDER BY EARLY EVENING. THE HIGHEST POPS WILL
BE IN THE FAR SOUTHWEST CORNER OF THE CWFA.
THE FACT THAT THE OVERALL CONVERGENCE IS WEAKENING WITH TIME PER THE
LIFT AND HEAVY RAIN TOOLS INDICATES THAT ANY CONVECTION THAT IS
OCCURRING ACROSS MISSOURI WILL BE STRATIFYING OUT AS IT MOVES INTO
THE CWFA. THUS ONLY RAIN IS EXPECTED THROUGH SUNSET.
FRIDAY NIGHT...THE WAA AND MOISTURE FINALLY WINS OUT OVER THE DRY
AIR BUT THE IMMEDIATE HWY 20 CORRIDOR WILL LIKELY REMAIN DRY THROUGH
MIDNIGHT. THE DRY EASTERLY FLOW WILL ALLOW EVAPORATIVE COOLING TO
OCCUR ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD. THIS
EVAPORATIVE COOLING WILL LIKELY RESULT IN A RAIN/SNOW MIX THAT
CHANGES OVER TO ALL SNOW IN THE HWY 20 CORRIDOR WITH ANY
ACCUMULATIONS BEING ONE HALF INCH OR LESS. THE HWY 30 CORRIDOR DOWN
TO ALMOST I-80 WILL LIKELY SEE A RAIN/SNOW MIX THAT DEVELOPS DURING
THE NIGHT.
SATURDAY ON...
MODEL CONSENSUS HAS LIKELY POPS FROM THE I-80 CORRIDOR ON SOUTH WITH
CHC POPS NORTH WHICH ARE LIKELY ON THE LOW SIDE. A RAIN/SNOW MIX
SHOULD BE ONGOING WITH SUNRISE OVER ROUGHLY THE NORTHERN 40 PERCENT
OF THE CWFA WITH RAIN ELSEWHERE. ANY MIX SHOULD CHANGE OVER TO A
VERY COLD RAIN AS THE DAY PROGRESSES. DYNAMIC COOLING COULD KEEP A
MIX GOING IN THE FAR NORTHWEST PART OF THE CWFA.
THE CONSENSUS GIVES CHC POPS SATURDAY NIGHT WITH SCHC POPS ON SUNDAY
AS ENERGY UPSTREAM KICKS THE STORM SYSTEM INTO THE EASTERN GREAT
LAKES. SUNDAY NIGHT THROUGH NEXT TUESDAY THE MODEL CONSENSUS HAS DRY
CONDITIONS ACROSS THE AREA AS NORTHWEST FLOW ALOFT DEVELOPS.
TEMPERATURES SATURDAY THROUGH TUESDAY SHOULD CONTINUE TO AVERAGE
ABOVE NORMAL BUT WILL BE MUCH CLOSER TO NORMAL SUNDAY THROUGH
TUESDAY. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-
JOHNSON-JONES-LINN-MUSCATINE-SCOTT.
IL...DENSE FOG ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR ROCK ISLAND.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
608 AM CST WED FEB 1 2012
.UPDATE...
STRATUS AND FOG CONTINUES TO ADVECT IN ON LLVL NORTHWEST FLOW. SEVERAL
SITES HAVE GONE DOWN AT OR BELOW 1/4SM ESPECIALLY ON THE IA SIDE
OF RIVER ALONG/N OF I-80. HAVE THEREFORE ISSUED DENSE FOG ADVISORY FOR
THIS AREA UNTIL 16Z. GIVEN STRENGTH OF INVERSION AND STRATUS COULD SEE
DENSE FOG PERSIST INTO THE AFTN.
&&
.AVIATION...
STRATUS AND FOG WITH AREAS OF DENSE FOG AND IFR TO VLIFR CONDITIONS
BLANKETING KCID... KDBQ AND KMLI TERMINALS AND APPROACHING KBRL.
REGIONAL SOUNDINGS WITHIN STRATUS AND FOG SHOW MOISTURE 500-1000 FT
THICK AND EXTENDS INTO STRONG INVERSION... THUS PRESENTING CHALLENGE
AND LOW CONFIDENCE ON CLEARING THIS AFTN INTO TNGT. LATEST HRRR AND
RUC BACKUP MODELS HAVE DECENT HANDLE ON STRATUS AND FOG... AND SHOW
IMPROVEMENT THIS AFTN INTO MVFR TO VFR CONDITIONS THIS AFTN AND
EARLY EVE... AS WARMER AIR MOVES IN WESTERLY FLOW AT AROUND 925 MB.
CONCERN FOR TNGT WILL BE WITH REDEVELOPMENT OF FOG THAT COULD BE DENSE
IN AREAS. LATEST RUC BACKUP DEPICTS MORE WIDESPREAD DENSE FOG BY LATE
EVE INTO OVRNGT... BUT LOW CONFIDENCE DUE TO CLOUD TRENDS PRECLUDES
FROM DENSE FOG WITH VLIFR CONDITIONS. DID LOWER VSBYS AT TERMINALS TO
1-2SM BY MID EVE FOR NOW AND WAIT TO SEE HOW CLOUD TRENDS GO TDY.
WINDS NORTHWEST 3-8 KTS BECOMING LIGHT WEST TO SOUTHWEST BY TNGT.
.05..
&&
.PREV DISCUSSION... /ISSUED 320 AM CST WED FEB 1 2012/
SYNOPSIS...
EARLY AM SFC ANALYSIS PLACES LOW NORTH OF LAKE HURON JUST TO NORTH OF
SUDBURY ONTARIO. COLD FRONT TRAILS FROM THE LOW THROUGH CENTRAL IN
INTO NORTH TX. WEAK RIDGING EXTENDS FROM CENTRAL PLAINS INTO THE
UPPER MIDWEST. STRATUS WHICH FORMED OVER THE DAKOTAS INTO WESTERN MN
YSTDY CONTINUES TO EXPAND AND SURGE SOUTHEAST AIDED BY COLD
ADVECTION OVER EXISTING SNOWPACK NORTH AND MOIST BL FROM SNOW MELT.
LATEST 11-3.9 MICRON SATL IMAGERY SHOWS LEADING EDGE OF THE STRATUS
FROM KVTI TO KFEP MOVING SOUTHEAST AT AROUND 12 KTS. SOME FOG ALSO
OCCURRING WITH STRATUS... BUT VSBYS GENERALLY AT OR ABOVE 3SM ATTIM.
SHORT TERM...TODAY AND TONIGHT...
CLOUD TRENDS WITH IMPACT ON TEMPS... AND FOG POTENTIAL MAIN FCST
CONCERNS.
MOST MODELS STRUGGLING TO CAPTURE CURRENT STRATUS DECK... EXCEPT
FOR LATEST RUNS OF HRRR AND RUC BACKUP MODELS VIA ESRL. THESE
MODELS GENERALLY SUPPORT CONTINUED SOUTHEAST MOVEMENT THROUGH
DAYBREAK WITH MOST OF AREA NORTH OF HWY 34 BLANKETED BY THE STRATUS
BY MID AM. ONE CONCERN IS THAT RECENT SATL TRENDS SEEM TO SHOW THE
STRATUS CONTINUING TO SLOW... AND MAY BE DUE IN PART TO OUTRUNNING
THE SNOW FIELD AND MORE MOIST BL FROM SNOW MELT PAST 24 HRS NORTH OF
HWY 30. JUST WHERE LEADING EDGE OF STRATUS RESIDES BY MID AM
LIKELY TO BE IT FOR MOVEMENT AS STRENGTHENING SOLAR INSOLATION
LIKELY TO IMPEDE FURTHER PROGRESS. OF COURSE WHERE THIS ENDS UP WILL
BE HUGE FACTOR ON HIGH TEMPS. ANOTHER FACTOR IS EVOLUTION OF THE
EXISTING STRATUS THIS AFTN INTO TNGT AND WHETHER ANY CLEARING CAN
TAKE PLACE. LATEST HRRR AND RUC BACKUP MODELS DO SUPPORT DECREASE IN
STRATUS THIS AFTN... WITH HRRR SLIGHTLY SLOWER AND NOT UNTIL MID AFTN.
0412Z AMDAR ASCENT SOUNDING FROM KMSP SIMILAR TO 00Z MPX RAOB AND
SHOWS MOIST LAYER 500-1000 FT THICK... WITH MOISTURE LINGERING INTO
STRONG INVERSION AND NOT JUST BELOW IT. THIS IS A CONCERN AS IS FACT
THAT AREA WILL RESIDE IN WEAK SYNOPTIC SCALE FLOW... THUS MIXING WILL
BE LIMITED TO TAP DRY AIR ALOFT AND PROMOTE EROSION. THEREFORE
FAVOR SLOWER CLEARING TRENDS FROM HRRR... BUT ALSO MUST WONDER IF THE
STRATUS DOESNT DISSIPATE THIS AFTN WHAT WOULD PROMOTE EVACUATION TNGT.
SOME MODELS DO SHOW WARMING IN 925 MB LAYER TNGT AS FLOW IN THIS
LAYER BECOMES WESTERLY IN ASSOCIATION WITH CLIPPER TYPE SYSTEM PASSING
WELL NORTH INTO NORTHERN MN AND WI. THIS MAY BE ENOUGH TO CHEW AWAY AT
ANY RESIDUAL STRATUS... AND FOR NOW SKY COVER GRIDS EVOLVING TO MORE
OPTIMISTIC IN TIME. AS FOR TDY... WILL BE HEAVILY NOWCASTING CURRENT
STRATUS DECK AND USING HRRR AND RUC BACKUP MODELS FOR TRENDS. FOR NOW
WILL GO WITH IDEA OF STRATUS NEARING HWY 34 BY MID AM THEN LINGERING
INTO AFTN WITH SLOW EROSION THROUGH THIS EVE. ALL AREAS TDY WILL BE
COOLER... BUT TEMPS STILL ABOVE NORMAL. COOLEST READINGS BENEATH THE
STRATUS WHERE TEMPS COULD STRUGGLE TO 40 DEGS IF THEY HOLD ALL DAY.
OTRW... WARMEST READINGS SOUTH WHERE U40S TO L50S LOOK LIKELY WITH SOME
INCREASING HIGH CLOUDINESS. IN SHORT... AS CLOUDS GO... SO GO THE TEMPS.
WITH SOME UNCERTAINTY ON CLOUD TRENDS TNGT STAYED NEAR GUIDANCE BLEND
ON LOW TEMPS. FOG A POSSIBILITY TNGT WITH LIGHT BL FLOW AND LLVL MOISTURE
ESPECIALLY IN THOSE AREAS THAT SEE CLEARING LATE DAY INTO EARLY EVE.
IF STRATUS LINGERS WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG FORM ON
WESTERN EDGE. TOO UNCERTAIN THOUGH FOR ANY MENTION ATTIM BUT PASS ON THE
CONCERN TO DAY CREW. ..05..
LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
DRY AND QUIET CONDITIONS WILL BE SEEN THURS/THURS NIGHT AS HIGH
PRESSURE MOVES ACROSS THE AREA. TEMPERATURES WILL CONTINUE TO
AVERAGE ABOVE NORMAL.
STARTING FRIDAY...THINGS BECOME MORE INTERESTING. DPROG/DT CONTINUES
TO SHOW A SUBTLE SLOWING OF THE RESPECTIVE MODEL SOLUTIONS. HIGH
PRESSURE FROM THE NORTHERN PLAINS INTO THE GREAT LAKES CONTINUES TO
TREND STRONGER INDICATING A DEEPER FETCH OF DRY EASTERLY FLOW. THE
MAJOR UNKNOWN IS THE ENERGY CURRENTLY ENTERING THE GULF OF ALASKA
AND HOW IT WILL KICK OUT THE CUT OFF LOW IN THE PLAINS. ALL MODELS
CONTINUE TO SHOW VARIABILITY WHICH IS TRACEABLE TO HOW THE
RESPECTIVE ENERGIES INTERACT WITH EACH OTHER.
SO...FRIDAY MORNING WILL BE DRY WITH INCREASING CLOUDS. ALL MODELS
SHOW STRONG FORCING AND LOW CONDENSATION PRESSURE DEFICITS FROM
MISSOURI INTO CENTRAL IOWA ALONG WITH A GOOD MOISTURE FEED. OVER THE
CWFA...ALL MODELS SHOW EASTERLY FLOW FROM THE SFC UP THROUGH 850MB.
THUS PRECIP WILL NOT BE FAR AWAY FROM THE FAR SOUTHWEST PART OF THE
CWFA BY MID DAY FRIDAY.
FRIDAY AFTERNOON...THE DEEP AND DRY EASTERLY FLOW CONTINUES ACROSS
THE CWFA. BY MID TO LATE AFTERNOON 850-700MB CONDENSATION PRESSURE
DEFICITS COLLAPSE OVER ROUGHLY THE SOUTHWEST QUARTER OF THE CWFA
WITH GOOD FORCING. THE MOISTURE FEED BEGINS MOVING INTO THE CWFA AS
WELL. THE HEAVY RAIN AND LIFT TOOLS SHOW THE STRONG CONVERGENCE IS
THERE BUT WEAKENING WITH TIME. THUS RAIN SHOULD DEVELOP/MOVE INTO
THE CWFA IN AN ARCING LINE FROM NORTHERN KEOKUK COUNTY TO ROUGHLY
THE HANCOCK/MCDONOUGH BORDER BY EARLY EVENING. THE HIGHEST POPS WILL
BE IN THE FAR SOUTHWEST CORNER OF THE CWFA.
THE FACT THAT THE OVERALL CONVERGENCE IS WEAKENING WITH TIME PER THE
LIFT AND HEAVY RAIN TOOLS INDICATES THAT ANY CONVECTION THAT IS
OCCURRING ACROSS MISSOURI WILL BE STRATIFYING OUT AS IT MOVES INTO
THE CWFA. THUS ONLY RAIN IS EXPECTED THROUGH SUNSET.
FRIDAY NIGHT...THE WAA AND MOISTURE FINALLY WINS OUT OVER THE DRY
AIR BUT THE IMMEDIATE HWY 20 CORRIDOR WILL LIKELY REMAIN DRY THROUGH
MIDNIGHT. THE DRY EASTERLY FLOW WILL ALLOW EVAPORATIVE COOLING TO
OCCUR ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD. THIS
EVAPORATIVE COOLING WILL LIKELY RESULT IN A RAIN/SNOW MIX THAT
CHANGES OVER TO ALL SNOW IN THE HWY 20 CORRIDOR WITH ANY
ACCUMULATIONS BEING ONE HALF INCH OR LESS. THE HWY 30 CORRIDOR DOWN
TO ALMOST I-80 WILL LIKELY SEE A RAIN/SNOW MIX THAT DEVELOPS DURING
THE NIGHT.
SATURDAY ON...
MODEL CONSENSUS HAS LIKELY POPS FROM THE I-80 CORRIDOR ON SOUTH WITH
CHC POPS NORTH WHICH ARE LIKELY ON THE LOW SIDE. A RAIN/SNOW MIX
SHOULD BE ONGOING WITH SUNRISE OVER ROUGHLY THE NORTHERN 40 PERCENT
OF THE CWFA WITH RAIN ELSEWHERE. ANY MIX SHOULD CHANGE OVER TO A
VERY COLD RAIN AS THE DAY PROGRESSES. DYNAMIC COOLING COULD KEEP A
MIX GOING IN THE FAR NORTHWEST PART OF THE CWFA.
THE CONSENSUS GIVES CHC POPS SATURDAY NIGHT WITH SCHC POPS ON SUNDAY
AS ENERGY UPSTREAM KICKS THE STORM SYSTEM INTO THE EASTERN GREAT
LAKES. SUNDAY NIGHT THROUGH NEXT TUESDAY THE MODEL CONSENSUS HAS DRY
CONDITIONS ACROSS THE AREA AS NORTHWEST FLOW ALOFT DEVELOPS.
TEMPERATURES SATURDAY THROUGH TUESDAY SHOULD CONTINUE TO AVERAGE
ABOVE NORMAL BUT WILL BE MUCH CLOSER TO NORMAL SUNDAY THROUGH
TUESDAY. ..08..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR BENTON-
BUCHANAN-CEDAR-CLINTON-DELAWARE-DUBUQUE-IOWA-JACKSON-
JOHNSON-JONES-LINN-MUSCATINE-SCOTT.
IL...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR ROCK ISLAND.
MO...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
320 AM CST WED FEB 1 2012
.SYNOPSIS...
EARLY AM SFC ANALYSIS PLACES LOW NORTH OF LAKE HURON JUST TO NORTH OF
SUDBURY ONTARIO. COLD FRONT TRAILS FROM THE LOW THROUGH CENTRAL IN
INTO NORTH TX. WEAK RIDGING EXTENDS FROM CENTRAL PLAINS INTO THE
UPPER MIDWEST. STRATUS WHICH FORMED OVER THE DAKOTAS INTO WESTERN MN
YSTDY CONTINUES TO EXPAND AND SURGE SOUTHEAST AIDED BY COLD
ADVECTION OVER EXISTING SNOWPACK NORTH AND MOIST BL FROM SNOW MELT.
LATEST 11-3.9 MICRON SATL IMAGERY SHOWS LEADING EDGE OF THE STRATUS
FROM KVTI TO KFEP MOVING SOUTHEAST AT AROUND 12 KTS. SOME FOG ALSO
OCCURRING WITH STRATUS... BUT VSBYS GENERALLY AT OR ABOVE 3SM ATTIM.
&&
.SHORT TERM...TODAY AND TONIGHT...
CLOUD TRENDS WITH IMPACT ON TEMPS... AND FOG POTENTIAL MAIN FCST
CONCERNS.
MOST MODELS STRUGGLING TO CAPTURE CURRENT STRATUS DECK... EXCEPT
FOR LATEST RUNS OF HRRR AND RUC BACKUP MODELS VIA ESRL. THESE
MODELS GENERALLY SUPPORT CONTINUED SOUTHEAST MOVEMENT THROUGH
DAYBREAK WITH MOST OF AREA NORTH OF HWY 34 BLANKETED BY THE STRATUS
BY MID AM. ONE CONCERN IS THAT RECENT SATL TRENDS SEEM TO SHOW THE
STRATUS CONTINUING TO SLOW... AND MAY BE DUE IN PART TO OUTRUNNING
THE SNOW FIELD AND MORE MOIST BL FROM SNOW MELT PAST 24 HRS NORTH OF
HWY 30. JUST WHERE LEADING EDGE OF STRATUS RESIDES BY MID AM
LIKELY TO BE IT FOR MOVEMENT AS STRENGTHENING SOLAR INSOLATION
LIKELY TO IMPEDE FURTHER PROGRESS. OF COURSE WHERE THIS ENDS UP WILL
BE HUGE FACTOR ON HIGH TEMPS. ANOTHER FACTOR IS EVOLUTION OF THE
EXISTING STRATUS THIS AFTN INTO TNGT AND WHETHER ANY CLEARING CAN
TAKE PLACE. LATEST HRRR AND RUC BACKUP MODELS DO SUPPORT DECREASE IN
STRATUS THIS AFTN... WITH HRRR SLIGHTLY SLOWER AND NOT UNTIL MID AFTN.
0412Z AMDAR ASCENT SOUNDING FROM KMSP SIMILAR TO 00Z MPX RAOB AND
SHOWS MOIST LAYER 500-1000 FT THICK... WITH MOISTURE LINGERING INTO
STRONG INVERSION AND NOT JUST BELOW IT. THIS IS A CONCERN AS IS FACT
THAT AREA WILL RESIDE IN WEAK SYNOPTIC SCALE FLOW... THUS MIXING WILL
BE LIMITED TO TAP DRY AIR ALOFT AND PROMOTE EROSION. THEREFORE
FAVOR SLOWER CLEARING TRENDS FROM HRRR... BUT ALSO MUST WONDER IF THE
STRATUS DOESNT DISSIPATE THIS AFTN WHAT WOULD PROMOTE EVACUATION TNGT.
SOME MODELS DO SHOW WARMING IN 925 MB LAYER TNGT AS FLOW IN THIS
LAYER BECOMES WESTERLY IN ASSOCIATION WITH CLIPPER TYPE SYSTEM PASSING
WELL NORTH INTO NORTHERN MN AND WI. THIS MAY BE ENOUGH TO CHEW AWAY AT
ANY RESIDUAL STRATUS... AND FOR NOW SKY COVER GRIDS EVOLVING TO MORE
OPTIMISTIC IN TIME. AS FOR TDY... WILL BE HEAVILY NOWCASTING CURRENT
STRATUS DECK AND USING HRRR AND RUC BACKUP MODELS FOR TRENDS. FOR NOW
WILL GO WITH IDEA OF STRATUS NEARING HWY 34 BY MID AM THEN LINGERING
INTO AFTN WITH SLOW EROSION THROUGH THIS EVE. ALL AREAS TDY WILL BE
COOLER... BUT TEMPS STILL ABOVE NORMAL. COOLEST READINGS BENEATH THE
STRATUS WHERE TEMPS COULD STRUGGLE TO 40 DEGS IF THEY HOLD ALL DAY.
OTRW... WARMEST READINGS SOUTH WHERE U40S TO L50S LOOK LIKELY WITH SOME
INCREASING HIGH CLOUDINESS. IN SHORT... AS CLOUDS GO... SO GO THE TEMPS.
WITH SOME UNCERTAINTY ON CLOUD TRENDS TNGT STAYED NEAR GUIDANCE BLEND
ON LOW TEMPS. FOG A POSSIBILITY TNGT WITH LIGHT BL FLOW AND LLVL MOISTURE
ESPECIALLY IN THOSE AREAS THAT SEE CLEARING LATE DAY INTO EARLY EVE.
IF STRATUS LINGERS WOULD NOT BE SURPRISED TO SEE SOME DENSE FOG FORM ON
WESTERN EDGE. TOO UNCERTAIN THOUGH FOR ANY MENTION ATTIM BUT PASS ON THE
CONCERN TO DAY CREW. ..05..
.LONG TERM...THURSDAY THROUGH NEXT TUESDAY...
DRY AND QUIET CONDITIONS WILL BE SEEN THURS/THURS NIGHT AS HIGH
PRESSURE MOVES ACROSS THE AREA. TEMPERATURES WILL CONTINUE TO
AVERAGE ABOVE NORMAL.
STARTING FRIDAY...THINGS BECOME MORE INTERESTING. DPROG/DT CONTINUES
TO SHOW A SUBTLE SLOWING OF THE RESPECTIVE MODEL SOLUTIONS. HIGH
PRESSURE FROM THE NORTHERN PLAINS INTO THE GREAT LAKES CONTINUES TO
TREND STRONGER INDICATING A DEEPER FETCH OF DRY EASTERLY FLOW. THE
MAJOR UNKNOWN IS THE ENERGY CURRENTLY ENTERING THE GULF OF ALASKA
AND HOW IT WILL KICK OUT THE CUT OFF LOW IN THE PLAINS. ALL MODELS
CONTINUE TO SHOW VARIABILITY WHICH IS TRACEABLE TO HOW THE
RESPECTIVE ENERGIES INTERACT WITH EACH OTHER.
SO...FRIDAY MORNING WILL BE DRY WITH INCREASING CLOUDS. ALL MODELS
SHOW STRONG FORCING AND LOW CONDENSATION PRESSURE DEFICITS FROM
MISSOURI INTO CENTRAL IOWA ALONG WITH A GOOD MOISTURE FEED. OVER THE
CWFA...ALL MODELS SHOW EASTERLY FLOW FROM THE SFC UP THROUGH 850MB.
THUS PRECIP WILL NOT BE FAR AWAY FROM THE FAR SOUTHWEST PART OF THE
CWFA BY MID DAY FRIDAY.
FRIDAY AFTERNOON...THE DEEP AND DRY EASTERLY FLOW CONTINUES ACROSS
THE CWFA. BY MID TO LATE AFTERNOON 850-700MB CONDENSATION PRESSURE
DEFICITS COLLAPSE OVER ROUGHLY THE SOUTHWEST QUARTER OF THE CWFA
WITH GOOD FORCING. THE MOISTURE FEED BEGINS MOVING INTO THE CWFA AS
WELL. THE HEAVY RAIN AND LIFT TOOLS SHOW THE STRONG CONVERGENCE IS
THERE BUT WEAKENING WITH TIME. THUS RAIN SHOULD DEVELOP/MOVE INTO
THE CWFA IN AN ARCING LINE FROM NORTHERN KEOKUK COUNTY TO ROUGHLY
THE HANCOCK/MCDONOUGH BORDER BY EARLY EVENING. THE HIGHEST POPS WILL
BE IN THE FAR SOUTHWEST CORNER OF THE CWFA.
THE FACT THAT THE OVERALL CONVERGENCE IS WEAKENING WITH TIME PER THE
LIFT AND HEAVY RAIN TOOLS INDICATES THAT ANY CONVECTION THAT IS
OCCURRING ACROSS MISSOURI WILL BE STRATIFYING OUT AS IT MOVES INTO
THE CWFA. THUS ONLY RAIN IS EXPECTED THROUGH SUNSET.
FRIDAY NIGHT...THE WAA AND MOISTURE FINALLY WINS OUT OVER THE DRY
AIR BUT THE IMMEDIATE HWY 20 CORRIDOR WILL LIKELY REMAIN DRY THROUGH
MIDNIGHT. THE DRY EASTERLY FLOW WILL ALLOW EVAPORATIVE COOLING TO
OCCUR ON THE NORTHERN EDGE OF THE PRECIPITATION SHIELD. THIS
EVAPORATIVE COOLING WILL LIKELY RESULT IN A RAIN/SNOW MIX THAT
CHANGES OVER TO ALL SNOW IN THE HWY 20 CORRIDOR WITH ANY
ACCUMULATIONS BEING ONE HALF INCH OR LESS. THE HWY 30 CORRIDOR DOWN
TO ALMOST I-80 WILL LIKELY SEE A RAIN/SNOW MIX THAT DEVELOPS DURING
THE NIGHT.
SATURDAY ON...
MODEL CONSENSUS HAS LIKELY POPS FROM THE I-80 CORRIDOR ON SOUTH WITH
CHC POPS NORTH WHICH ARE LIKELY ON THE LOW SIDE. A RAIN/SNOW MIX
SHOULD BE ONGOING WITH SUNRISE OVER ROUGHLY THE NORTHERN 40 PERCENT
OF THE CWFA WITH RAIN ELSEWHERE. ANY MIX SHOULD CHANGE OVER TO A
VERY COLD RAIN AS THE DAY PROGRESSES. DYNAMIC COOLING COULD KEEP A
MIX GOING IN THE FAR NORTHWEST PART OF THE CWFA.
THE CONSENSUS GIVES CHC POPS SATURDAY NIGHT WITH SCHC POPS ON SUNDAY
AS ENERGY UPSTREAM KICKS THE STORM SYSTEM INTO THE EASTERN GREAT
LAKES. SUNDAY NIGHT THROUGH NEXT TUESDAY THE MODEL CONSENSUS HAS DRY
CONDITIONS ACROSS THE AREA AS NORTHWEST FLOW ALOFT DEVELOPS.
TEMPERATURES SATURDAY THROUGH TUESDAY SHOULD CONTINUE TO AVERAGE
ABOVE NORMAL BUT WILL BE MUCH CLOSER TO NORMAL SUNDAY THROUGH
TUESDAY. ..08..
&&
.AVIATION...
STRATUS WITH IFR TO LIFR CIGS AND LIGHT FOG BLANKETING KDBQ AND FAST
APPROACHING KCID TERMINAL AT 09Z. THE STRATUS IS ADVANCING SE AT 12 KTS
BUT LATEST SATL LOOP SUGGEST SOME SLOWING... WHICH WILL MAKE LOW CLOUD
FCST FOR KMLI AND ESPECIALLY KBRL QUITE TRICKY. WHERE THE STRATUS ENDS
UP BY DAYBREAK OR SHORTLY THEREAFTER LIKELY TO BE END POINT WITH
INCREASING SUNSHINE HALTING PROGRESS. WILL CONTINUE TO MONITOR LOW CLOUD
TRENDS AND AMEND AS NEEDED. AMDAR SOUNDINGS AT KMSP SHOW CLOUDS
500-1000 FT THICK AND EXTENDS INTO STRONG INVERSION... THUS MAKING
CLEARING LOW CONFIDENCE FOR THIS AFTN AND TNGT. SOME WARMING AT 925 MB
BY TNGT MAY END UP CHEWING AWAY AT THE STRATUS. POTENTIAL FOR FOG TNGT
WHICH COULD BE DENSE IN SOME AREAS ESPECIALLY WHERE SKIES CLEAR LATE TDY
INTO EVE. WINDS NORTHWEST 5-10 KTS BECOMING LIGHT WEST TO SOUTHWEST BY TNGT.
..05..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
05/08
AREA FORECAST DISCUSSION...UPDATED
NWS PITTSBURGH PA
1235 AM EST WED FEB 1 2012
.SYNOPSIS...
A WEAK COLD FRONT WILL BRING SHOWERS TO THE AREA THROUGH THE
MORNING HOURS. HIGH PRESSURE WILL PROVIDE A DRY END TO THE WORK
WEEK.
&&
.NEAR TERM /THROUGH TODAY/...
AREA OF SHOWERS MOVING THROUGH THE SOUTHERN HALF OF THE REGION.
THESE SHOWERS ARE MOVING EASTWARD WITH A PRE-FRONTAL SHORTWAVE. THE
WAVE WILL SHIFT INTO C PA BEFORE DAWN, AS THE SFC FRONT REACHES MY
WESTERN COUNTIES. EXPECT ANOTHER LINE OF SHOWERS AFTER DAWN RIGHT
ALONG THE FRONT. BOUNDARY WILL CLEAR THE AREA BY EARLY AFTERNOON,
SO WILL HAVE THE HIGHEST POPS IN THE MORNING HOURS. WEAK CAA
BEHIND FRONT WILL BRING COOLER TEMPERATURES TODAY, BUT READINGS
WILL REMAIN ABOVE NORMAL.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
FRONT WILL STALL OVER THE MID-ATLANTIC TONIGHT, AS SFC HIGH MOVES
OVER THE GREAT LAKES. A WEAK SFC WAVE WILL MOVE ALONG THE STALLED
FRONT TONIGHT AND COULD POSSIBLY BRING A FEW SHOWERS TO MY FAR
SOUTHEASTERN ZONES. ONCE THIS WAVE MOVES OFF THE EAST COAST, HIGH
PRESSURE WILL SETTLE IN OVER THE ENTIRE UPPER OHIO VALLEY.
TEMPERATURES FOR THE REMAINDER OF THE SHORT TERM WILL REMAIN A BIT
ABOVE NORMAL.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
MORE SO THAN THE LAST FEW DAYS...THE DETERMINISTIC MODELS AND
ENSEMBLE MEANS HAVE BEGUN TO SUGGEST VERY SIMILAR SCENARIOS IN
EJECTION OF THE 500HPA LOW THROUGH THE CENTRAL U.S AND TOWARDS THE
REGION. THE MODELS THAT YESTERDAY SUGGESTED A NEARLY STATIONARY
CUTOFF LOW OVER THE EASTERN ROCKIES...HAVE SPED UP TO A CLOSER
GEFS/GFS SOLUTION THAT HAS BE PREVALENT FOR A FEW DAYS. THE SPLIT
FLOW CONTINUES TO MAKE SOME OF THE FORECAST VARIABLES DIFFICULT
HOWEVER...ESPECIALLY IN REGARDS TO TIMING AND LOCATION OF THE
SURFACE LOW AS IT CROSSES THE OHIO VALLEY.
CONTINUED TO FOLLOW CLOSELY TO HPC GUIDANCE, BUT TOOK THE MOST RECENT
RUNS OF THE GEFS...GFS...AND ECMWF INTO ACCOUNT. KEPT CHANCE POPS IN
THE FORECAST SATURDAY THROUGH SUNDAY AS THE LOW CROSSES. USED A
BLEND OF HPC AND TO A GREATER EXTENT MEX GUIDANCE THROUGH TUESDAY.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS WILL CONTINUE THIS EVE BUT WL BE MARRED BY
INCREASING...AND LOWERING MID LVL CLDINESS AS STRNG...WARM...MOIST
ADVCTN CONTS IN ADVN OF STRNG LOW PRES MOVG ACRS THE NRN LAKES.
-SHRA ACTIVITY WL ALSO BE ON THE INCRS...BUT RESTRICTIONS ARE NOT
ANTICIPATED UNTIL THE LLVLS GET CLOSER TO SATURATION LTR TNGT. MVFR
IS CONFIDENTLY FORECAST IN THE POST MIDNGT PD...AND SHOULD DOMINATE
AREA TAFS UNTIL FRONTAL PASSAGE LTR ON WEDNESDAY MRNG.
ALSO OF CONCERN IS THE INCREASING INDICATIONS OF MORE LLWS AS
PROGGED VIA THE LATEST NAM AND RUC MDL SOUNDINGS. HAVE THUS ADDED
THIS POTENTIAL FOR THE EVE TAF ISSUANCES WITH NR 50 KTS FORECAST
ABOVE THE INVERSION LEVEL...I.E. ARND 2 KFT...AGAIN UNTIL FRONTAL
PASSAGE LTR ON WED MRNG.
OUTLOOK...WEDNESDAY NIGHT THROUGH SATURDAY...
LATEST DETERMINISTIC MDL SOLNS INDICATE THAT LOW PRES MOVING ALNG
FRONTAL BOUNDARY SHOULD PASS SUFFICIENTLY SOUTH OF UPR OH VALLEY
TERMINALS TO PRECLUDE WIDESPREAD RESTRICTIONS ON WED NGT. SFC WND
WL SHIFT TO THE NW IN THE WAKE OF THAT SYS ON THURSDAY WITH COLD
ADVCTN SPAWNING SOME LAKE/UPSLOPE ENHANCED STRATOCUMULUS. VFR
CONDITIONS ARE EXPECTED TO RTN FRIDAY...BUT ANOTHER LOW MAY DEGRADE
CONDTIONS AGAIN FOR THE WEEKEND.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
555 PM EST WED FEB 1 2012
.AVIATION...
//DISCUSSION...
RECENT MODEL GUIDANCE PROVIDING LITTLE ASSISTANCE IN DEFINING THE
CLOUD DETAILS FOR TONIGHT AND BEYOND...WITH RELIANCE THIS TAF
ISSUANCE LARGELY LEANING ON LATEST TRENDS IN SATELLITE AND
OBSERVATIONAL DATA. THE MOST RECENT DATA SET SUGGEST THE EXPANSIVE
MVFR STRATUS DECK NOW ENCOMPASSING ALL OF SOUTHEAST MICHIGAN WILL
STRUGGLE TO BUDGE THIS EVENING AS MIXING CEASES AND SUFFICIENT
MOISTURE REMAINS TUCKED BENEATH ESTABLISHED INVERSION LAYER. THIS
POINTS TOWARD LEANING MORE PESSIMISTIC IN CARRYING A PROLONGED MVFR
CEILING THROUGH THE NIGHT. NARROW POCKET OF CLEARING EMERGING
SOUTH/EAST OF DTW WILL BE WORTH MONITORING. SHOULD SOME LARGER BREAKS
IN THE DECK DEVELOP OVERNIGHT...THEN A WEAK GRADIENT WOULD SUPPORT A
BRIEF DIP IN VISIBILITY /4-6SM/ WITHIN A 10-14Z WINDOW.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE THAT CEILING WILL REMAIN BELOW 5000 FEET
TONIGHT. LOW CONFIDENCE ON THURSDAY.
&&
.PREV DISCUSSION...ISSUED 340 PM EST WED FEB 1 2012
SHORT TERM...THIS EVENING AND TONIGHT
HIGH PRESSURE SYSTEM OVER THE UPPER MISSISSIPPI VALLEY WILL
BUILD OVER THE GREAT LAKES OVERNIGHT WITH THE RIDGE AXIS OVERHEAD BY
AROUND 12Z. WITH THE PRESSURE GRADIENT ALREADY RELAXING...WIND
SPEEDS ALREADY ON THE DECLINE WILL CONTINUE UNTIL THEY ARE LIGHT AND
VARIABLE BY MORNING. THE MAIN FORECAST CONCERN IS WITH CLOUD/FOG
POTENTIAL FOR THE OVERNIGHT. STRATUS DECK AROUND 3KFT MANAGED TO
FILL IN OVER ALL OF SE MI THIS MORNING EXTENDING BACK WEST INTO
IA/MN...UNDER THE NORTH SIDE OF THE RIDGE AXIS THAT WILL BE MOVING
OVERHEAD TONIGHT. EXPECT THIS LOW STRATUS DECK TO THIN OUT SOMEWHAT
THIS EVENING WHILE HIGHER CIRRUS CLOUDS THICKEN TONIGHT. RUC MODEL
SOUNDINGS AGREE WITH THIS THINKING THOUGH IT KEEPS LOW LEVEL
MOISTURE VALUES QUITE HIGH IN THE LOWEST 3KFT. THE NAM DOES ITS
USUAL AND IS EVEN MORE ROBUST WITH BOUNDARY LAYER SO LEANING MORE
TOWARD RUC. SO MODELS SHOW THERE IS POTENTIAL FOR THE STRATUS TO
LINGER LONGER THROUGH THE NIGHT. EVEN THOUGH MANY OF THE ASOS
STATIONS IN IA/MN/WI REPORTED FOG WITH VISIBILITY RESTRICTIONS DOWN
TO 2-4 MILES EARLY THIS MORNING...THE ABUNDANT CLOUD COVER WE WILL
HAVE IN PLACE SHOULD PREVENT MUCH FOG FORMATION IF ANY. RAISED MIN
TEMPS TONIGHT A DEGREE OR 2 TO ACCOUNT FOR THE THICKER CLOUDS.
LONG TERM...THURSDAY THROUGH NEXT WEDNESDAY
FORECAST CONTINUES TO LOOK FAIRLY QUIET DURING THE EXTENDED
PERIOD...AT LEAST FOR FEBRUARY. TEMPERATURES WILL CONTINUE TO RUN
ABOVE NORMAL INTO THE BEGINNING OF NEXT WEEK BEFORE A STRONG COLD
FRONT DROPS TEMPERATURES BACK CLOSER TO NORMAL NEXT WEDNESDAY.
UPPER SHORTWAVE OVER SOUTHERN MANITOBA THIS AFTERNOON WILL DROP DOWN
ACROSS THE NORTHERN GREAT LAKES THURSDAY. THIS SHOULD KEEP THE
SURFACE RIDGE INTACT OVER SOUTHEAST LOWER MICHIGAN...WHILE A WEAK
SURFACE TROUGH SLIDES ACROSS NORTHERN MICHIGAN IN RESPONSE. THINK
LIGHT SNOW SHOWERS WILL STAY NORTH OF THE AREA AND HAVE KEPT THE
FORECAST DRY...WITH THE MAIN IMPACT FROM THIS SHORTWAVE EXPECTED TO
BE AN INCREASE IN MID LEVEL MOISTURE OVER CENTRAL MICHIGAN. MODEL
FORECAST SOUNDINGS THROUGH THURSDAY NIGHT KEEP A SUBSIDENCE
INVERSION IN PLACE ACROSS SOUTHEAST MICHIGAN...GENERALLY BETWEEN
900-800MB. ALTHOUGH GFS/NAM DO NOT SHOW AN OVERABUNDANCE OF
LOW-LEVEL MOISTURE REMAINING TRAPPED IN THE LOWER LEVELS...DID LEAN
MORE PESSIMISTIC WITH THE SKY COVER FORECAST (MORE CLOUDS) THAN
MODELS SUGGEST GIVEN POOR MIXING AND LIGHT WEST TO NORTHWEST FLOW
OFF LAKE MICHIGAN. ASSUMING THERE IS A LOWER CLOUD DECK...WILL HAVE
TO SEE IF MID-LEVEL MOISTURE OVERRUNNING ANY MOISTURE TRAPPED
UNDERNEATH THE SUBSIDENCE INVERSION COULD SEED LOWER CLOUDS ACROSS
CENTRAL MICHIGAN...WHICH WOULD MAYBE PRODUCE SOME FLURRIES. GIVEN
THE EXPECTATION FOR MORE CLOUDS AND VERY LIGHT WINDS/POOR
MIXING...WENT ON THE COOL SIDE OF MOS GUIDANCE FOR HIGHS
THURSDAY...IN THE MID 30S TO LOW 40S.
THE RIDGE WILL THEN RESTRENGTHEN OVER THE CENTRAL GREAT LAKES
THURSDAY NIGHT AND FRIDAY...BEFORE ANOTHER UPPER SHORTWAVE DROPS
DOWN THROUGH THE CENTRAL GREAT LAKES FRIDAY NIGHT. GFS/NAM BRING A
WEAK FRONT DOWN ACROSS THE AREA WITH THIS FEATURE...BUT IT LOOKS
MOISTURE STARVED AND SHOULD DO LITTLE BUT INCREASE CLOUDS ONCE
AGAIN. NAM IS SLOWER WITH BOTH THE FRONT AND SOUTHWARD PROGRESS WITH
THIS WAVE ACROSS THE GREAT LAKES FRIDAY/FRIDAY NIGHT...AND HAVE
THEREFORE HEAVILY FAVORED THE OTHER MODELS WITH THE ARRIVAL OF
LOW-LEVEL MOISTURE AND PRECIPITATION LATE FRIDAY NIGHT INTO
SATURDAY. WITH THE SLOWER TIMING...NAM ALLOWS AN APPROACHING LOW
PRESSURE SYSTEM AND ASSOCIATED AREA OF DEFORMATION TO MAKE QUICKER
AND FURTHER INROADS INTO THE SOUTHERN GREAT LAKES.
REX BLOCK PATTERN WILL DEVELOP OVER THE WEST COAST BY FRIDAY...PER
STRONG CONSENSUS FROM FORECAST MODELS. THIS BLOCK WILL THEN VERY
SLOWLY MAKES IT WAY EAST INTO THE CENTRAL CONUS AND TOPPLE OVER THE
WEEKEND. MODELS REMAIN VERY DIVIDED ON HOW LONG IT WILL TAKE THE
UPPER LOW ON THE SOUTHERN END OF THE BLOCK TO LIFT UP INTO THE
SOUTHERN GREAT LAKES. SPREAD IS ANYWHERE FROM SATURDAY NIGHT (12Z
GFS) TO EARLY MONDAY (12Z GEM)...AND CONFIDENCE SURROUND TIMING OF
WEATHER IMPACTS FROM THIS FEATURE ARE VERY LOW. UKMET/GEM/EURO KEEP
THE SYSTEM FAR ENOUGH SOUTH OF THE AREA NOW TO SUPPORT A DRY
FORECAST THROUGH AT LEAST SATURDAY NIGHT. DID HOWEVER KEEP A SLIGHT
CHANCE FOR RAIN/SNOW NEAR THE OHIO BORDER SATURDAY AFTERNOON AND
OVERNIGHT...WITH LOW CHANCES FOR LIGHT SNOW SHOWERS BY SUNDAY NIGHT.
UPPER TROUGHING LOOKS TO BUILD OVER THE NORTHEASTERN PORTION OF
NORTH AMERICA AND THE GREAT LAKES TOWARDS THE MIDDLE OF THE
WEEK...WITH SEVERAL SHORTWAVE TROUGHS DROPPING DOWN ACROSS THE AREA
MONDAY THROUGH WEDNESDAY. GFS/EURO ALSO AGREE WITH A FAIRLY STRONG
COLD FRONT DROPPING DOWN THROUGH MICHIGAN ON TUESDAY (THOUGH THERE
REMAIN SLIGHT TIMING DIFFERENCES). THIS WOULD BRING A QUICK SHOT OF
SNOW SHOWERS AND DROP TEMPERATURES BACK DOWN TO NEAR NORMAL BY
WEDNESDAY.
MARINE...
HIGH PRESSURE OVER THE WESTERN GREAT LAKES WILL BUILD EASTWARD
OVERNIGHT WITH THE RIDGE AXIS ACROSS LAKE HURON BY THURSDAY MORNING.
THE PRESSURE GRADIENT HAS ALREADY WEAKENED SUBSTANTIALLY THROUGH THE
DAY ALLOWING WINDS TO DECREASE WITH MAX GUSTS REACHING 20 KNOTS OVER
THE OPEN WATERS OF LAKE HURON. WINDS AND WAVE WILL CONTINUE TO
DECREASE THROUGH THE NIGHT AS THE RIDGE AXIS DRAWS NEARER. THIS HIGH
PRESSURE SYSTEM WILL PRODUCE VERY FAVORABLE MARINE CONDITIONS INTO
THE WEEKEND. A LOW PRESSURE TROUGH WILL PASS THROUGH THE REGION ON
THURSDAY...THOUGH IT WILL BE VERY WEAK AND WILL MOST LIKELY NOT BE
ABLE TO PUT A DENT IN THE LARGER SCALE RIDGE IN PLACE.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
AVIATION.....MR
SHORT TERM...DRK
LONG TERM....HLO
MARINE.......DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
415 PM EST WED FEB 1 2012
LATEST UPDATE...ALL EXCEPT AVIATION...
.SYNOPSIS...(415 PM EST WED FEB 1 2012)
HIGH PRESSURE WILL PROVIDE TRANQUIL WEATHER INTO FRIDAY WITH
GENERALLY PARTLY CLOUDY SKIES. MILD CONDITIONS WILL CONTINUE WITH
HIGH TEMPERATURES FORECAST TO PUSH TO AROUND 40 BOTH THURSDAY AND
FRIDAY. NORMAL HIGHS FOR THIS TIME OF YEAR AROUND NEAR 30 DEGREES.
A SYSTEM MAY APPROACH THE SOUTHERN GREAT LAKES OVER THE WEEKEND AND
BRUSH THE AREA WITH A CHANCE OF LIGHT SNOW AND LIGHT RAIN. AT THIS
POINT IT APPEARS THE BRUNT OF THE SYSTEM IN THE FORM OF RAINFALL
WILL BE SOUTH OF THE AREA.
&&
.SHORT TERM...(415 PM EST WED FEB 1 2012)
(TONIGHT THROUGH FRIDAY NIGHT)
NOT MUCH IN THE WAY OF CONCERNS THROUGH THE SHORT TERM. MAIN ITEM
WILL BE THE EXTENT OF LOW CLOUDS TONIGHT. DECIDED GIVEN CLIMATOLOGY
TO ROLL WITH LOWER CLOUDS TRYING TO HANG ON. USED A MOSTLY CLOUDY
WORDING THROUGH THE NIGHT FOR NOW. BUFKIT RUC OVERVIEWS SHOW
MOISTURE HANGING ON BETWEEN 2000-3500FT INTO THURSDAY MORNING. THERE
MAY BE SOME EBB AND FLOW TO THE CLOUDS THOUGH AS THERE IS A CLEARING
LINE PRESSING IN FROM THE SOUTHWEST. ENVISION SOME CLEARING THIS
EVENING WITH THE CLOUDS FILLING BACK IN OVERNIGHT.
BEYOND TONIGHT...GENERALLY A PARTLY CLOUDY FORECAST WITH SURFACE
HIGH PRESSURE IN PLACE. COMPLICATING FACTORS THOUGH ARE A SHORTWAVE
DIVING SOUTHEAST ON THURSDAY WHICH MAY INCREASE CLOUD COVER AND
POTENTIALLY SOME LOW CLOUDS FILTERING IN BEHIND THE WAVE THURSDAY
NIGHT AND FRIDAY.
&&
.LONG TERM...(415 PM EST WED FEB 1 2012)
(SATURDAY THROUGH WEDNESDAY)
FORECAST CONCERNS CONTINUE TO BE THE LOW MOVING OUT OF THE SRN
PLAINS OVER THE WEEKEND.
THE GFS REMAINS CONSISTENT IN MOVING THE LOW FROM OKLAHOMA EAST
ACROSS THE OHIO VALLEY. THE NAM IS ON BOARD WITH THIS SOLUTION. THE
ECMWF IS NOW GIVING A NOD TO THE GFS BY DEVELOPING A LOW OVER
KENTUCKY AND THEN SHEARING IT OUT INTO A TROUGH OVER THE
APPALACHIANS. WITH THE ECMWF NOW WEAKENING IT/S LOW OVER IOWA AND
DEVELOPING ONE FARTHER SOUTH...CONFIDENCE IS INCREASING THAT A LOW
WILL MOVE ACROSS THE OHIO VALLEY OVER THE WEEKEND. THIS TRACK
COUPLED WITH FORECAST SOUNDINGS ALSO SUGGESTS THAT ALL THE PCPN WILL
BE SNOW. HOW MUCH PCPN WE SEE IS STILL UP IN THE AIR...SO TO SPEAK.
BOTH THE NAM/GFS SHOW A NICE SLUG OF PCPN BEHIND THE LOW LIKELY
ASSOCIATED WITH DEFORMATION PROCESSES. HIGHEST CHANCES FOR PCPN WILL
BE ALONG/SOUTH OF I-96 SATURDAY AND SUNDAY. MONDAY LOOKS DRY BEFORE
ANOTHER SHORT WAVE MOVING SOUTH ACROSS THE GREAT LAKES BOOSTS PCPN
CHANCES TUESDAY/WEDNESDAY. TEMPS WILL BE MOSTLY ABOVE NORMAL THROUGH
THE PERIOD.
&&
.AVIATION...(103 PM EST WED FEB 1 2012)
MVFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD. A LARGE EXPANSE OF
LOW CLOUDS STRETCHES ACROSS THE UPPER MIDWEST. MODEL RH PROGS SHOW
ABUNDANT LOW LEVEL MOISTURE BELOW 4K FT THROUGH TONIGHT. LOOK FOR
CIGS IN THE 1500-2500 RANGE.
&&
.MARINE...(415 PM EST WED FEB 1 2012)
SURFACE RIDGING WILL BE SITUATED OVER THE GREAT LAKES AREA THE NEXT
36 HOURS OF SO...PROVIDING RELATIVELY TRANQUIL CONDITIONS OUT ON THE
LAKE. WAVES AROUND 1 FOOT ARE EXPECTED INTO FRIDAY WITH WINDS OF 10
KNOTS OR LESS.
&&
.HYDROLOGY...(415 PM EST WED FEB 1 2012)
RAIN IN THE LAST WEEK OR SO...COMBINED WITH SNOWMELT THE LAST COUPLE
OF DAYS HAS LED TO ELEVATED RIVER LEVELS ACROSS THE AREA. THAT
SAID...MOST SITES REMAIN...OR ARE FORECAST TO REMAIN WITHIN BANK.
THE USGS PERCENT OF NORMAL PAGE INDICATES THAT MOST SITES ARE IN
EITHER THE ABOVE NORMAL OR MUCH ABOVE NORMAL CATEGORY. THE KALAMAZOO
RIVER BASIN AND THE UPPER REACHES OF THE GRAND ARE THE HIGHEST. WE
CURRENTLY HAVE RIVER FLOOD ADVISORIES OUT FOR BURLINGTON...VICKSBURG
AND IONIA. THESE SITES ARE NOT PROJECT TO REACH WARNING STATUS. WITH
DRY WEATHER FORECAST THE NEXT COUPLE DAYS...RIVER HEADLINES SHOULD
REMAIN FAIRLY STABLE.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE
LONG TERM: 93
AVIATION: 93
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS DETROIT/PONTIAC MI
340 PM EST WED FEB 1 2012
.SHORT TERM...THIS EVENING AND TONIGHT
HIGH PRESSURE SYSTEM OVER THE UPPER MISSISSIPPI VALLEY WILL
BUILD OVER THE GREAT LAKES OVERNIGHT WITH THE RIDGE AXIS OVERHEAD BY
AROUND 12Z. WITH THE PRESSURE GRADIENT ALREADY RELAXING...WIND
SPEEDS ALREADY ON THE DECLINE WILL CONTINUE UNTIL THEY ARE LIGHT AND
VARIABLE BY MORNING. THE MAIN FORECAST CONCERN IS WITH CLOUD/FOG
POTENTIAL FOR THE OVERNIGHT. STRATUS DECK AROUND 3KFT MANAGED TO
FILL IN OVER ALL OF SE MI THIS MORNING EXTENDING BACK WEST INTO
IA/MN...UNDER THE NORTH SIDE OF THE RIDGE AXIS THAT WILL BE MOVING
OVERHEAD TONIGHT. EXPECT THIS LOW STRATUS DECK TO THIN OUT SOMEWHAT
THIS EVENING WHILE HIGHER CIRRUS CLOUDS THICKEN TONIGHT. RUC MODEL
SOUNDINGS AGREE WITH THIS THINKING THOUGH IT KEEPS LOW LEVEL
MOISTURE VALUES QUITE HIGH IN THE LOWEST 3KFT. THE NAM DOES ITS
USUAL AND IS EVEN MORE ROBUST WITH BOUNDARY LAYER SO LEANING MORE
TOWARD RUC. SO MODELS SHOW THERE IS POTENTIAL FOR THE STRATUS TO
LINGER LONGER THROUGH THE NIGHT. EVEN THOUGH MANY OF THE ASOS
STATIONS IN IA/MN/WI REPORTED FOG WITH VISIBILITY RESTRICTIONS DOWN
TO 2-4 MILES EARLY THIS MORNING...THE ABUNDANT CLOUD COVER WE WILL
HAVE IN PLACE SHOULD PREVENT MUCH FOG FORMATION IF ANY. RAISED MIN
TEMPS TONIGHT A DEGREE OR 2 TO ACCOUNT FOR THE THICKER CLOUDS.
&&
.LONG TERM...THURSDAY THROUGH NEXT WEDNESDAY
FORECAST CONTINUES TO LOOK FAIRLY QUIET DURING THE EXTENDED
PERIOD...AT LEAST FOR FEBRUARY. TEMPERATURES WILL CONTINUE TO RUN
ABOVE NORMAL INTO THE BEGINNING OF NEXT WEEK BEFORE A STRONG COLD
FRONT DROPS TEMPERATURES BACK CLOSER TO NORMAL NEXT WEDNESDAY.
UPPER SHORTWAVE OVER SOUTHERN MANITOBA THIS AFTERNOON WILL DROP DOWN
ACROSS THE NORTHERN GREAT LAKES THURSDAY. THIS SHOULD KEEP THE
SURFACE RIDGE INTACT OVER SOUTHEAST LOWER MICHIGAN...WHILE A WEAK
SURFACE TROUGH SLIDES ACROSS NORTHERN MICHIGAN IN RESPONSE. THINK
LIGHT SNOW SHOWERS WILL STAY NORTH OF THE AREA AND HAVE KEPT THE
FORECAST DRY...WITH THE MAIN IMPACT FROM THIS SHORTWAVE EXPECTED TO
BE AN INCREASE IN MID LEVEL MOISTURE OVER CENTRAL MICHIGAN. MODEL
FORECAST SOUNDINGS THROUGH THURSDAY NIGHT KEEP A SUBSIDENCE
INVERSION IN PLACE ACROSS SOUTHEAST MICHIGAN...GENERALLY BETWEEN
900-800MB. ALTHOUGH GFS/NAM DO NOT SHOW AN OVERABUNDANCE OF
LOW-LEVEL MOISTURE REMAINING TRAPPED IN THE LOWER LEVELS...DID LEAN
MORE PESSIMISTIC WITH THE SKY COVER FORECAST (MORE CLOUDS) THAN
MODELS SUGGEST GIVEN POOR MIXING AND LIGHT WEST TO NORTHWEST FLOW
OFF LAKE MICHIGAN. ASSUMING THERE IS A LOWER CLOUD DECK...WILL HAVE
TO SEE IF MID-LEVEL MOISTURE OVERRUNNING ANY MOISTURE TRAPPED
UNDERNEATH THE SUBSIDENCE INVERSION COULD SEED LOWER CLOUDS ACROSS
CENTRAL MICHIGAN...WHICH WOULD MAYBE PRODUCE SOME FLURRIES. GIVEN
THE EXPECTATION FOR MORE CLOUDS AND VERY LIGHT WINDS/POOR
MIXING...WENT ON THE COOL SIDE OF MOS GUIDANCE FOR HIGHS
THURSDAY...IN THE MID 30S TO LOW 40S.
THE RIDGE WILL THEN RESTRENGTHEN OVER THE CENTRAL GREAT LAKES
THURSDAY NIGHT AND FRIDAY...BEFORE ANOTHER UPPER SHORTWAVE DROPS
DOWN THROUGH THE CENTRAL GREAT LAKES FRIDAY NIGHT. GFS/NAM BRING A
WEAK FRONT DOWN ACROSS THE AREA WITH THIS FEATURE...BUT IT LOOKS
MOISTURE STARVED AND SHOULD DO LITTLE BUT INCREASE CLOUDS ONCE
AGAIN. NAM IS SLOWER WITH BOTH THE FRONT AND SOUTHWARD PROGRESS WITH
THIS WAVE ACROSS THE GREAT LAKES FRIDAY/FRIDAY NIGHT...AND HAVE
THEREFORE HEAVILY FAVORED THE OTHER MODELS WITH THE ARRIVAL OF
LOW-LEVEL MOISTURE AND PRECIPITATION LATE FRIDAY NIGHT INTO
SATURDAY. WITH THE SLOWER TIMING...NAM ALLOWS AN APPROACHING LOW
PRESSURE SYSTEM AND ASSOCIATED AREA OF DEFORMATION TO MAKE QUICKER
AND FURTHER INROADS INTO THE SOUTHERN GREAT LAKES.
REX BLOCK PATTERN WILL DEVELOP OVER THE WEST COAST BY FRIDAY...PER
STRONG CONSENSUS FROM FORECAST MODELS. THIS BLOCK WILL THEN VERY
SLOWLY MAKES IT WAY EAST INTO THE CENTRAL CONUS AND TOPPLE OVER THE
WEEKEND. MODELS REMAIN VERY DIVIDED ON HOW LONG IT WILL TAKE THE
UPPER LOW ON THE SOUTHERN END OF THE BLOCK TO LIFT UP INTO THE
SOUTHERN GREAT LAKES. SPREAD IS ANYWHERE FROM SATURDAY NIGHT (12Z
GFS) TO EARLY MONDAY (12Z GEM)...AND CONFIDENCE SURROUND TIMING OF
WEATHER IMPACTS FROM THIS FEATURE ARE VERY LOW. UKMET/GEM/EURO KEEP
THE SYSTEM FAR ENOUGH SOUTH OF THE AREA NOW TO SUPPORT A DRY
FORECAST THROUGH AT LEAST SATURDAY NIGHT. DID HOWEVER KEEP A SLIGHT
CHANCE FOR RAIN/SNOW NEAR THE OHIO BORDER SATURDAY AFTERNOON AND
OVERNIGHT...WITH LOW CHANCES FOR LIGHT SNOW SHOWERS BY SUNDAY NIGHT.
UPPER TROUGHING LOOKS TO BUILD OVER THE NORTHEASTERN PORTION OF
NORTH AMERICA AND THE GREAT LAKES TOWARDS THE MIDDLE OF THE
WEEK...WITH SEVERAL SHORTWAVE TROUGHS DROPPING DOWN ACROSS THE AREA
MONDAY THROUGH WEDNESDAY. GFS/EURO ALSO AGREE WITH A FAIRLY STRONG
COLD FRONT DROPPING DOWN THROUGH MICHIGAN ON TUESDAY (THOUGH THERE
REMAIN SLIGHT TIMING DIFFERENCES). THIS WOULD BRING A QUICK SHOT OF
SNOW SHOWERS AND DROP TEMPERATURES BACK DOWN TO NEAR NORMAL BY
WEDNESDAY.
&&
.MARINE...
HIGH PRESSURE OVER THE WESTERN GREAT LAKES WILL BUILD EASTWARD
OVERNIGHT WITH THE RIDGE AXIS ACROSS LAKE HURON BY THURSDAY MORNING.
THE PRESSURE GRADIENT HAS ALREADY WEAKENED SUBSTANTIALLY THROUGH THE
DAY ALLOWING WINDS TO DECREASE WITH MAX GUSTS REACHING 20 KNOTS OVER
THE OPEN WATERS OF LAKE HURON. WINDS AND WAVE WILL CONTINUE TO
DECREASE THROUGH THE NIGHT AS THE RIDGE AXIS DRAWS NEARER. THIS HIGH
PRESSURE SYSTEM WILL PRODUCE VERY FAVORABLE MARINE CONDITIONS INTO
THE WEEKEND. A LOW PRESSURE TROUGH WILL PASS THROUGH THE REGION ON
THURSDAY...THOUGH IT WILL BE VERY WEAK AND WILL MOST LIKELY NOT BE
ABLE TO PUT A DENT IN THE LARGER SCALE RIDGE IN PLACE.
&&
.AVIATION...ISSUED 1241 PM EST WED FEB 1 2012
//DISCUSSION...
MAIN CONCERN FOR THIS ISSUANCE IS THE STRATUS DECK THAT FILLED IN
OVER SOUTHEAST MICHIGAN THIS MORNING. SHORT TERM MODELS STILL
DISAGREE AS TO WHETHER DAYTIME HEATING WILL SCATTER OUT THE STRATUS
OR NOT THIS AFTERNOON. JUDGING FROM 12Z SOUNDINGS FROM DTX/APX IT
APPEARS THAT THE INVERSION IS STRONGER THEN FORECAST WHICH WILL KEEP
THE STRATUS FROM MIXING OUT. THUS HAVE GONE MORE PESSIMISTIC HOLDING
MVFR CIGS INTO THIS EVENING. HIGH PRESSURE AND CIRRUS MOVING IN FROM
THE WEST ADD A LEVEL OF COMPLEXITY TO THE FORECAST AS TO POTENTIAL
VISIBILITY RESTRICTIONS FOR FOG OVERNIGHT. UPSTREAM OBSERVATIONS
SHOWED MANY LOCATIONS WITH MVFR/IFR VSBYS LAST NIGHT...BUT AS
MENTIONED THE CIRRUS AND HIGH PRESSURE WILL WORK AGAINST THAT. AT
THIS POINT JUST LEFT A MENTION OF LOW SCATTERED CLOUDS AS CONFIDENCE
IS LOW THAT FOG WILL FORM.
//DTW THRESHOLD THREATS...
* MODERATE CONFIDENCE THAT CEILING WILL REMAIN BELOW 5000 FEET INTO
THIS EVENING.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LAKE HURON...NONE.
LAKE ST CLAIR...NONE.
MI WATERS OF LAKE ERIE...NONE.
&&
$$
SHORT TERM...DRK
LONG TERM....HLO
MARINE.......DRK
AVIATION.....DRK
YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE
AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE).
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
103 PM EST WED FEB 1 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(410 AM EST WED FEB 1 2012)
TEMPERATURES WILL CONTINUE TO AVERAGE ABOVE NORMAL THROUGH THE
WEEKEND INTO EARLY NEXT WEEK. TRANQUIL WEATHER IS ANTICIPATED
THROUGH AT LEAST FRIDAY. LOW PRESSURE TRACKING EAST FROM THE PLAINS
MAY BRING SOME PRECIPITATION BY SATURDAY.
&&
.SHORT TERM...(1134 AM EST WED FEB 1 2012)
(THIS AFTERNOON THROUGH FRIDAY AFTERNOON)
UPDATED TO GO MOSTLY CLOUDY THROUGH THE AFTERNOON. RUC AND GFS LOW
LEVEL MOISTURE PROGS INDICATE QUITE A BIT OF MOISTURE HANGING ON.
THERE ARE A FEW BREAKS IN THE OVERCAST DEVELOPING IN WISCONSIN AND
ILLINOIS...BUT THE AFTERNOON WILL AT LEAST START OFF MOSTLY CLOUDY.
THINKING WAS RIDGING BUILDING IN WOULD KNOCK OUT SOME OF THE
MOISTURE...BUT IT APPEARS THE TRAPPING INVERSION MAY BE TOO STRONG.
BOTH THE DETROIT AND GREEN BAY MORNING SOUNDINGS INDICATE A FAIRLY
STRONG INVERSION. OTHER THAN THE PESKY LOW CLOUDS...CONDITIONS ARE
RATHER QUIET THIS AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS...
A SHORTWAVE MOVING THROUGH LATE TONIGHT INTO THURSDAY MORNING MAY
BRING A LITTLE MORE CLOUD COVER BUT NO PCPN.
A SFC RIDGE IN CONJUNCTION WITH AN UPPER RIDGE BUILDING IN FROM THE
WEST THURSDAY THROUGH THURSDAY NIGHT WILL BRING FAIR AND SEASONABLY
MILD WX THURSDAY THROUGH THURSDAY NIGHT INTO FRIDAY. MAX TEMPS
THURSDAY AND FRIDAY WILL REACH THE LOWER 40S ACROSS MOST OF OUR FCST
AREA.
&&
.LONG TERM...(410 AM EST WED FEB 1 2012)
(FRIDAY NIGHT THROUGH TUESDAY)
MODELS ARE IN GOOD AGREEMENT ON THE POSITION OF THE CENTRAL PLAINS
UPPER LOW THROUGH 12Z SATURDAY BUT THEN DIVERGE SIGNIFICANTLY AFTER
THAT. AS SUCH... THIS IS A LOW CONFIDENCE LONG TERM FORECAST IN
TERMS OF PCPN POTENTIAL OVER THE WEEKEND.
THE GENERAL IDEA/THEME SEEMS TO BE THAT PCPN RELATED TO THE CENTRAL
PLAINS SYSTEM WILL HAVE A DIFFICULT TIME MAKING MUCH HEADWAY INTO
SRN LWR MI OVER THE WEEKEND. THIS IS DUE TO A RESISTANT CONFLUENT
MID/UPR FLOW OVERHEAD (RELATED TO THE UPR TROUGH IN ERN CANADA) AND
A DRY AIR MASS IN PLACE. NO BIG CHANGES THEREFORE ARE NEEDED ATTM TO
THE WEEKEND FCST... WHICH INCLUDES ONLY LOW CHANCE POPS FOR SNOW OR
MIXED PCPN.
FOR EARLY NEXT WEEK...GUIDANCE SUGGESTS THAT WHATEVER REMAINS OF THE
AFOREMENTIONED UPPER LOW/TROUGH WILL EVENTUALLY GET ABSORBED/PHASED
IN WITH A NRN STREAM TROUGH COMING DOWN FROM THE NORTHWEST. HAVE
THEREFORE KEPT SOME LOW CHANCE POPS GOING FOR MONDAY AND TUESDAY OF
NEXT WEEK.
WHILE THE PCPN ASPECT OF THE LONG TERM FCST IS LOW CONFIDENCE...
THERE IS HIGH CONFIDENCE THAT TEMPERATURES WILL CONTINUE TO AVERAGE
ABOVE NORMAL THROUGH EARLY NEXT WEEK.
&&
.AVIATION...(103 PM EST WED FEB 1 2012)
MVFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD. A LARGE EXPANCE OF
LOW CLOUDS STRECHES ACROSS THE UPPER MIDWEST. MODEL RH PROGS SHOW
ABUNDANT LOW LEVEL MOISTURE BELOW 4K FT THROUGH TONIGHT. LOOK FOR
CIGS IN THE 1500-2500 RANGE.
&&
.MARINE...(410 AM EST WED FEB 1 2012)
THE SCA REMAINS IN EFFECT UNTIL 7 AM THIS MORNING. WAVE HEIGHTS WILL
SUBSIDE TO 2 TO 4 FEET LATER THIS MORNING AND TO 1 TO 3 FEET BY THIS
AFTERNOON AS HIGH PRESSURE BUILDS IN AND NORTHWEST WINDS DIMINISH.
&&
.HYDROLOGY...(410 AM EST WED FEB 1 2012)
NO SIGNIFICANT HYDRO ISSUES ANTICIPATED THIS WEEK WITH SEASONABLY
MILD AND DRY CONDITIONS THROUGH FRIDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY IN EFFECT THROUGH 7 AM TODAY FOR THE
ENTIRE NEARSHORE.
&&
$$
SYNOPSIS: LAURENS
SHORT TERM: LAURENS/DUKE
LONG TERM: MEADE
AVIATION: 93
MARINE: LAURENS
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1134 AM EST WED FEB 1 2012
LATEST UPDATE...SHORT TERM...
.SYNOPSIS...(410 AM EST WED FEB 1 2012)
TEMPERATURES WILL CONTINUE TO AVERAGE ABOVE NORMAL THROUGH THE
WEEKEND INTO EARLY NEXT WEEK. TRANQUIL WEATHER IS ANTICIPATED
THROUGH AT LEAST FRIDAY. LOW PRESSURE TRACKING EAST FROM THE PLAINS
MAY BRING SOME PRECIPITATION BY SATURDAY.
&&
.SHORT TERM...(1134 AM EST WED FEB 1 2012)
(THIS AFTERNOON THROUGH FRIDAY AFTERNOON)
UPDATED TO GO MOSTLY CLOUDY THROUGH THE AFTERNOON. RUC AND GFS LOW
LEVEL MOISTURE PROGS INDICATE QUITE A BIT OF MOISTURE HANGING ON.
THERE ARE A FEW BREAKS IN THE OVERCAST DEVELOPING IN WISCONSIN AND
ILLINOIS...BUT THE AFTERNOON WILL AT LEAST START OFF MOSTLY CLOUDY.
THINKING WAS RIDGING BUILDING IN WOULD KNOCK OUT SOME OF THE
MOISTURE...BUT IT APPEARS THE TRAPPING INVERSION MAY BE TOO STRONG.
BOTH THE DETROIT AND GREEN BAY MORNING SOUNDINGS INDICATE A FAIRLY
STRONG INVERSION. OTHER THAN THE PESKY LOW CLOUDS...CONDITIONS ARE
RATHER QUIET THIS AFTERNOON.
PREVIOUS DISCUSSION FOLLOWS...
A SHORTWAVE MOVING THROUGH LATE TONIGHT INTO THURSDAY MORNING MAY
BRING A LITTLE MORE CLOUD COVER BUT NO PCPN.
A SFC RIDGE IN CONJUNCTION WITH AN UPPER RIDGE BUILDING IN FROM THE
WEST THURSDAY THROUGH THURSDAY NIGHT WILL BRING FAIR AND SEASONABLY
MILD WX THURSDAY THROUGH THURSDAY NIGHT INTO FRIDAY. MAX TEMPS
THURSDAY AND FRIDAY WILL REACH THE LOWER 40S ACROSS MOST OF OUR FCST
AREA.
&&
.LONG TERM...(410 AM EST WED FEB 1 2012)
(FRIDAY NIGHT THROUGH TUESDAY)
MODELS ARE IN GOOD AGREEMENT ON THE POSITION OF THE CENTRAL PLAINS
UPPER LOW THROUGH 12Z SATURDAY BUT THEN DIVERGE SIGNIFICANTLY AFTER
THAT. AS SUCH... THIS IS A LOW CONFIDENCE LONG TERM FORECAST IN
TERMS OF PCPN POTENTIAL OVER THE WEEKEND.
THE GENERAL IDEA/THEME SEEMS TO BE THAT PCPN RELATED TO THE CENTRAL
PLAINS SYSTEM WILL HAVE A DIFFICULT TIME MAKING MUCH HEADWAY INTO
SRN LWR MI OVER THE WEEKEND. THIS IS DUE TO A RESISTANT CONFLUENT
MID/UPR FLOW OVERHEAD (RELATED TO THE UPR TROUGH IN ERN CANADA) AND
A DRY AIR MASS IN PLACE. NO BIG CHANGES THEREFORE ARE NEEDED ATTM TO
THE WEEKEND FCST... WHICH INCLUDES ONLY LOW CHANCE POPS FOR SNOW OR
MIXED PCPN.
FOR EARLY NEXT WEEK...GUIDANCE SUGGESTS THAT WHATEVER REMAINS OF THE
AFOREMENTIONED UPPER LOW/TROUGH WILL EVENTUALLY GET ABSORBED/PHASED
IN WITH A NRN STREAM TROUGH COMING DOWN FROM THE NORTHWEST. HAVE
THEREFORE KEPT SOME LOW CHANCE POPS GOING FOR MONDAY AND TUESDAY OF
NEXT WEEK.
WHILE THE PCPN ASPECT OF THE LONG TERM FCST IS LOW CONFIDENCE...
THERE IS HIGH CONFIDENCE THAT TEMPERATURES WILL CONTINUE TO AVERAGE
ABOVE NORMAL THROUGH EARLY NEXT WEEK.
&&
.AVIATION...(645 AM EST WED FEB 1 2012)
MVFR CIGS OF 1500-2500 FEET WERE SPREADING INTO SRN LWR MI EARLY
THIS MORNING FROM THE NORTH AND WEST. HOWEVER LOW LEVEL RH PROGS
SUGGEST THESE CLOUDS SHOULD SCOUR OUT BY 18Z DUE TO STRONG
SUBSIDENCE... SO WENT VFR FOR THIS AFTERNOON AND TONIGHT.
&&
.MARINE...(410 AM EST WED FEB 1 2012)
THE SCA REMAINS IN EFFECT UNTIL 7 AM THIS MORNING. WAVE HEIGHTS WILL
SUBSIDE TO 2 TO 4 FEET LATER THIS MORNING AND TO 1 TO 3 FEET BY THIS
AFTERNOON AS HIGH PRESSURE BUILDS IN AND NORTHWEST WINDS DIMINISH.
&&
.HYDROLOGY...(410 AM EST WED FEB 1 2012)
NO SIGNIFICANT HYDRO ISSUES ANTICIPATED THIS WEEK WITH SEASONABLY
MILD AND DRY CONDITIONS THROUGH FRIDAY.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY IN EFFECT THROUGH 7 AM TODAY FOR THE
ENTIRE NEARSHORE.
&&
$$
SYNOPSIS: LAURENS
SHORT TERM: LAURENS/DUKE
LONG TERM: MEADE
AVIATION: MEADE
MARINE: LAURENS
HYDROLOGY: LAURENS
AREA FORECAST DISCUSSION
NWS WILMINGTON NC
955 PM EST THU FEB 2 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE CAROLINAS FROM THE NORTH AND
REMAIN INTO THE FIRST PART OF THE WEEKEND. WEAK LOW PRESSURE AND ITS
ASSOCIATED FRONTAL SYSTEM WILL BRING A PERIOD OF UNSETTLED WEATHER
EARLY NEXT WEEK. A COLD FRONT WILL SWEEP ACROSS THE AREA MONDAY
NIGHT...ENDING THE CHANCE OF RAINFALL.
&&
.NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM THURSDAY...ASIDE FROM TWEAKING THE HOURLY TEMPERATURE
CURVE TO ACCOUNT FOR SOME UNEXPECTEDLY GOOD RADIATIONAL COOLING OUT
AHEAD OF THE INCOMING NORTHERLY SURGE...VERY FEW CHANGES WERE NEEDED
TO THE FORECAST WITH THIS MID-EVENING UPDATE. THE SURGE OF COLD AIR
HAS REACHED NORTHERN NORTH CAROLINA THIS EVENING AND WILL ENTER THE
CAPE FEAR REGION SHORTLY AFTER MIDNIGHT...SPREADING INTO
NORTHEASTERN SOUTH CAROLINA IN THE PRE-DAWN HOURS FRIDAY.
TEMPERATURES HAVE FALLEN INTO THE LOWER 50S FOR MANY LOCATIONS THIS
EVENING AND MAY SLIP INTO THE UPPER 40S BEFORE THE SURGE ARRIVES.
TEMPERATURES SHOULD EVENTUALLY FALL TO AROUND 40 BY DAYBREAK FRIDAY
WITH ONLY A FEW SHREDS OF THIN CIRRUS ALOFT.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...MINOR H5 RIDGE AXIS ACROSS THE SOUTH FRIDAY
WILL FLATTEN WITH A ZONE OF CONFLUENCE ALOFT BECOMING ESTABLISHED
NORTH OF OUR REGION SATURDAY. AT THE SURFACE...HIGH PRESSURE WILL
BUILD OVER THE CAROLINAS FRI-SAT...THEN A WARM FRONT IS EXPECTED TO
DEVELOP JUST NORTH OR ALONG THE NORTHERN TIER OF THE FORECAST AREA
SATURDAY NIGHT. TIME HEIGHT CROSS SECTIONS INDICATE A DRY COLUMN AND
LIFT LACKING FRIDAY THROUGH SATURDAY. NEXT CHANCE OF RAIN WILL BE
SATURDAY NIGHT WITH LOW-MID LEVEL MOISTURE ADVECTION AND LOW-LEVEL
UPWARD VERTICAL VELOCITIES COINCIDING WITH THE AFOREMENTIONED
DEVELOPING WARM FRONT IN THE VICINITY. TEMPS WILL CONTINUE ABOVE
CLIMO EACH PERIOD...EXCEPT FOR FRIDAY NIGHT.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 2 PM THURSDAY...FRONT WILL BE LURKING NOT FAR TO THE NORTH AT
THE START OF THE PERIOD...BRINGING SOME LOW RAIN CHANCES OVER MAINLY
NRN ZONES. BOTH WILL SINK SOUTH AS THE DAY WEARS ON IN RESPONSE TO
UPPER SYSTEM OFF OF NEW ENGLAND. SUNDAY HIGH TEMP FORECAST HIGHLY
UNCERTAIN BUT TRENDED DOWN IN LIGHT OF POSSIBILITY OF CLOUDS/LIGHT
RAIN AND THE FACT THAT SRN ZONES MAY HEAT UP SOME AHEAD OF THE
BOUNDARY. ADJUSTED MAXES TO SHOW N-S RANGE OF HIGHS FROM MID 50S TO
LOW 60S. SOME GUIDANCE HINTING THAT SRN ZONES COULD GET EVEN WARMER.
RAINFALL PROSPECTS APPEAR LOW SAVE FOR PERHAPS IMMEDIATE CAPE FEAR
REGION WHERE WEAK CONVECTIVE SIGNAL IS SEEN IN GUIDANCE. BEHIND THE
BOUNDARY DRY ADVECTION IS WEAK AND SHORT-LIVED WITH A TRAILING VORT
APPROACHING FROM THE NW SUNDAY NIGHT ALREADY TURNING 850MB FLOW BACK
TO SRLY AND THERE IS INDICATIONS OF COASTAL TROUGINESS DEVELOPS AT
THE SFC. THIS WILL KEEP THE FCST RATHER UNSETTLED INTO MONDAY
ALTHOUGH THE HIGH QPF SEEN IN THE ECMWF LOOKS DUBIOUS. LARGER HIGH
BUILDS IN FROM THE NW TUESDAY SHUNTING DEEPEST MOISTURE OFF THE
COAST AND KNOCKING TEMPS BACK TO CLIMO.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
AS OF 00Z...HIGH PRESSURE BUILDING INTO THE AREA WILL ALLOW FOR VFR
TO PREVAIL THROUGH THE VALID TAF PERIOD. NORTHWEST WINDS OVERNIGHT
AROUND 5 KTS WILL GRADUALLY VEER...BECOMING NORTHEAST AFTER
DAYBREAK. SUSTAINED WINDS THROUGHOUT THE DAY ON FRIDAY WILL BE AOB
12 KTS...WITH GUSTS UP TO NEAR 20 KTS POSSIBLE ALONG THE COAST.
AFTER SUNSET...ANTICIPATE WINDS TO DECREASE TO AROUND 5-8 KTS. SKIES
WILL REMAIN CLEAR THROUGH MUCH OF THE PERIOD...WITH FEW/SCT CIRRUS
INFILTRATING INTO THE AREA BY THE END OF THE PERIOD.
EXTENDED OUTLOOK...LOW CONFIDENCE FOR IFR ASSOCIATED WITH RAIN
SUNDAY. OTHERWISE EXPECT VFR.
&&
.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM THURSDAY...AFTER COLLABORATION WITH NWS CHARLESTON SC
WE HAVE DECIDED TO EXTEND THE SMALL CRAFT ADVISORY TO INCLUDE THE
COASTAL WATERS FROM MURRELLS INLET TO THE SOUTH SANTEE RIVER. THIS
IS DUE TO THE LATEST RUC AND HRRR MODELS SHOWING THE GRADIENT REALLY
TIGHTENING UP ACROSS SOUTHERN AND CENTRAL SOUTH CAROLINA LATE
TONIGHT WITH 20-25 KT WINDS EXPECTED. THIS WILL ALSO LIKELY BUILD
THE SEAS TO 6 FT IN THE 10-20 MILE OFFSHORE AREA EAST OF WINYAH BAY.
THE LEADING EDGE OF THE INCOMING SURGE IS CURRENTLY ENTERING
NORTHERN NORTH CAROLINA AND SHOULD REACH CAPE FEAR SHORTLY SHORTLY
AFTER MIDNIGHT...AND THE GRAND STRAND AND WINYAH BAY BY 3 AM. THIS
SURGE IS THE RESULT OF HIGH PRESSURE OVER THE GREAT LAKES PUSHING
SOUTH TOWARD THE CAROLINAS. UNTIL THE STRONGER WINDS ARRIVE AFTER
MIDNIGHT...GENERALLY LIGHT NORTH WINDS AROUND 10 KNOTS AND 2-3 FT
SEAS CAN BE EXPECTED.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 2 PM THURSDAY...COLD AIR ADVECTION ACROSS THE WATERS IN THE
WAKE OF THE COLD FRONT WILL WEAKEN DURING FRIDAY. WINDS WILL START
OUT GUSTY...ESPECIALLY AWAY FROM THE COAST...THEN DIMINISH BY FRIDAY
AFTERNOON. THE CENTER OF HIGH PRESSURE WILL PREVAIL OVER NC FRIDAY
NIGHT...THEN WEAKEN AND SHIFT EAST DURING SATURDAY AS A WARM FRONT
BEGINS TO DEVELOP JUST NORTH OF THE WATERS SATURDAY NIGHT. GFS IS
LIKELY ON THE HIGH SIDE WITH WIND SPEEDS SOUTH OF THE WARM FRONT
GIVEN WARM AIR ADVECTION ACROSS COOL SHELF WATERS. SEAS WILL BE
HIGHEST FRIDAY MORNING...THEN THEY WILL SUBSIDE BY FRIDAY NIGHT INTO
SATURDAY MORNING. SEAS WILL INCREASE SOME BY SATURDAY NIGHT.
LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 2 PM THURSDAY...PERIOD INITIALIZES WITH COLD FRONT VERY NEAR
OR PERHAPS EVEN ENTERING NRN ZONES...WITH A SLOW SOUTHWARD MOVEMENT
THAT WILL BRING A SHARP VEER N TO S AS THE AFTERNOON WEARS ON. BY
EVENING A NRLY COMPONENT WILL BE FOUND ACRS ALL WATERS AND A GRADUAL
ABATING OF SPEED MAY OCCUR. MODELS SHOWING A WEAK SFC COASTAL TROUGH
DEVELOP MONDAY AND ITS POSITION AND MOVEMENT WILL GENERALLY BRING
LIGHT WINDS BUT ALSO SOME UNCERTAINTY INTO THE FCST. WEAK EXITING
WAVE THEN PUSHES IT ALL OFF THE COAST AS HIGH BUILDS IN FROM THE NW
BY TUESDAY. THE SUNDAY NIGHT/MONDAY POST FRONTAL PINCHED GRADIENT
COULD BRIEFLY LEAD TO A PERIOD OF 3 TO 5 FT SEAS THAT WOULD CALL FOR
CAUTIONARY HEADLINES. THE REMAINDER OF THE PERIOD WILL BRING A
GENERAL 2 TO 3 FT WIND WAVE.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 10 AM EST FRIDAY FOR
AMZ250-252-256.
&&
$$
NEAR TERM...TRA
SHORT TERM...SRP
LONG TERM...MBB
AVIATION...SGL
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
850 PM CST THU FEB 2 2012
.DISCUSSION...
FOG CONTINUES TO BE THE FORECAST CHALLENGE TONIGHT...ALONG WITH
HOW IT AND STRATUS AFFECT TEMPERATURES. OTHER THAN THE
NORTHWESTERN COUNTIES AND A NARROW STRIP FROM NEAR FOSSTON TO
DETROIT LAKES...THE REST OF THE CWA HAS GONE DOWN WITH LOW STRATUS
AND FOG THIS EVENING. WILL CONTINUE TO KEEP THE DENSE FOG ADVISORY
THAT WE HAVE GOING...BUT WILL MONITOR THE NORTHWESTERN COUNTIES IN
CASE THE ADVISORY NEEDS TO BE EXPANDED. INCREASED FOG MENTION IN
THE WX GRIDS TO WIDESPREAD DENSE AFTER MIDNIGHT OVER ALL BUT THE
FAR NORTHWEST AS EVEN THE FEW LOCATIONS THAT HAVE HIGHER VIS
SHOULD CONTINUE TO DETERIORATE OVERNIGHT. WITH A FEW CLEAR SPOTS
THIS EVENING...TEMPERATURES HAVE BEEN PRETTY VARIABLE WITH THE
FOGGY AREAS STAYING IN THE MID TO UPPER 20S WHILE MANY CLEAR SPOTS
HAVE DROPPED INTO THE UPPER TEENS. MID LEVEL CLOUDS HAVE KEPT
TEMPS UP IN THE DEVILS LAKE BASIN. LOWERED TEMPS A BIT IN THE
NORTHERN VALLEY REGION WHERE CLOUDS HAVE BEEN A BIT LESS...AND
RAISED LOWS IN A FEW OTHER PLACES.
&&
.AVIATION...
VERY LOW IFR CURRENTLY ACROSS ALL TAF SITES EXCEPT KDVL
TONIGHT...AND THERE WILL BE LITTLE IF ANY IMPROVEMENT UNTIL AFTER
15Z TOMORROW. LIGHT WINDS AND PLENTY OF MOISTURE WILL NOT ALLOW
FOR FOG TO DISSIPATE AND MOST LOCATIONS WILL BE 1/2SM IF NOT 1/4SM
FOR MUCH OF THE OVERNIGHT. THINK THAT STRATUS WILL SPREAD NORTH TO
KDVL AFTER 06Z...BUT DO NOT THINK THAT VIS WILL BE QUITE AS LOW IN
THAT AREA. WILL MONITOR BUT JUST INCLUDE IFR CONDITIONS IN THE TAF
FOR NOW. THERE MAY BE SOME IMPROVEMENT TO VIS BACK UP OVER A MILE
BY LATE MORNING...BUT OVERALL FOG WILL BE SLOW TO DISSIPATE AND
CONDITIONS WILL NOT RETURN TO VFR OR EVEN MVFR UNTIL LATER IN THE
AFTERNOON WHEN WINDS START TO SHIFT OVER TO THE WEST.
&&
.PREV DISCUSSION... /ISSUED 332 PM CST THU FEB 2 2012/
SHORT TERM...TONIGHT THROUGH SUNDAY
FOG WILL BE THE PRIMARY FORECAST CHALLENGE TONIGHT THROUGH
TOMORROW AND THEN TEMPERATURES INTO THE WEEKEND. GFS/NAM/ECMWF/
GEM ARE IN GOOD AGREEMENT AND WILL USE A MODEL BLEND.
DENSE FOG HAS BEEN STATIONARY SINCE THIS MORNING ACROSS PORTIONS
OF THE SOUTHERN VALLEY AND NORTHWEST/WEST CENTRAL MN...WHEREAS
OTHER AREAS HAVE SEEN SOME IMPROVEMENT SINCE EARLY AFTERNOON. HIGH
LOW-LEVEL MOISTURE COMBINED WITH LITTLE TO NO WIND WILL ALLOW
CLEAR AREAS THIS AFTERNOON TO FILL IN QUITE RAPIDLY AFTER SUNSET.
LATEST HRRR MODEL RUN SHOWS VISIBILITY DROPPING TO BELOW 1/2 MILE
ACROSS MOST OF THE FORECAST AREA. WILL ISSUE A DENSE FOG ADVISORY
FOR AREAS ALONG AND SOUTHEAST OF A LINE FROM COOPERSTOWN TO GRAND
FORKS TO HALLOCK FROM 00 UTC TONIGHT UNTIL 15 UTC FRIDAY MORNING.
EXPECT PERIODS OF DENSE FOG WITH VISIBILITY REDUCTIONS TO NEAR
ZERO AT TIMES. TEMPERATURES WILL BE BELOW ZERO...SO SOME FREEZING
FOG IS POSSIBLE RESULTING IN SLICK SPOTS ON AREA ROADWAYS AND
SIDEWALKS...BUT LOW VISIBILITY IS THE GREATER HAZARD. MOTORISTS
SHOULD PREPARE FOR RAPIDLY CHANGING DRIVING CONDITIONS THROUGH
THE NIGHT. WITH FOG...TEMPERATURES WILL NOT DROP MUCH AND BOTTOM
OUT IN THE UPPER TEENS TO LOWER 20S.
AS SURFACE HIGH PRESSURE PERSISTS ACROSS THE NORTHERN PLAINS...
WINDS WILL REMAIN LIGHT AND FOG MAY BE VERY SLOW TO DISSIPATE
DURING THE DAY ON FRIDAY. BECAUSE OF THIS...INCREASED SKY COVER
AND LOWERED TEMPERATURES WITH HIGHS AROUND 30 DEGREES. SURFACE
HIGH CENTER MOVES TO THE SOUTH FOR THE WEEKEND...INCREASING THE
PRESSURE GRADIENT ACROSS THE FORECAST AREA. WESTERLY WINDS WILL
INCREASE FROM 5 TO 10 MPH...WHICH SHOULD BE ENOUGH TO LIMIT
ADDITIONAL FOG FORMATION...BUT THIS IS SOMETHING TO WATCH.
ASSUMING LESS FOG...MORE SUN AND A WARMING WESTERLY WIND...
TEMPERATURES SATURDAY AND SUNDAY SHOULD CLIMB INTO THE MID TO
UPPER 30S EACH DAY. SUNDAY IN PARTICULAR MAY BE QUITE WARM WITH
SOME AREAS REACHING INTO THE 40S.
LONG TERM...SUNDAY NIGHT THROUGH THURSDAY
MODELS ARE IN GOOD OVERALL AGREEMENT WITH THE GFS A BIT MORE
CONSISTENT WITH COOL DOWN NEXT WEEK. THE OVERALL QUIET WEATHER
PATTERN CONTINUES WITH TEMPERATURES COOLING BELOW NORMAL BY NEXT
THU. WILL CONTINUE WITH A DRY FORECAST AS A COLD FRONT AND NW FLOW
ALOFT MOVE INTO THE NORTHERN PLAINS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...DENSE FOG ADVISORY UNTIL 10 AM CST FRIDAY FOR NDZ027>030-038-039-
049-052-053.
MN...DENSE FOG ADVISORY UNTIL 10 AM CST FRIDAY FOR MNZ001>009-013>017-
022>024-027>032-040.
&&
$$
JR
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1207 PM EST WED FEB 1 2012
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL MOVE EAST OF THE REGION THIS
MORNING. HIGH PRESSURE OVER THE WESTERN GREAT LAKES LATER TODAY
WILL MOVE OVER THE LOCAL AREA BY EARLY FRIDAY. THIS HIGH WILL
SHIFT TO THE EAST COAST BY THE START OF THE WEEKEND BUT MAINTAIN A
RIDGE ACROSS THE UPPER OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ADJUSTED CLOUDS FOR REST OF AFTERNOON TO ALLOW TO MORE CU AND
STRATOCU. ALSO ADJUSTED TEMPS FOR AFTERNOON DOWN WHERE MORE CLOUDS
EXPECTED AND UP IN THE SOUTH AND SE WHERE AFTERNOON SHOULD REMAIN
PARTLY CLOUDY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE REMAINDER OF THE
WEEK. AN UPPER WAVE WILL DIVE SE ACROSS THE CENTRAL LAKES ON
THURSDAY. THIS FEATURE WILL BRING SOME MID AND HIGH LEVEL
CLOUDINESS TO THE AREA BUT LOW LEVELS WILL REMAIN TOO DRY FOR ANY
PRECIP CONCERNS. THE HIGH WILL REESTABLISH ITSELF ON FRIDAY AND
FRIDAY NIGHT. THIS WILL RESULT IN MORE PARTLY CLOUDY TO MOSTLY
CLEAR SKIES. MODELS BEGIN TO DIVERGE ON SATURDAY WITH THE LOW
PRESSURE SYSTEM HEADING NE OUT OF THE SOUTHERN PLAINS. THE LATEST
GFS AND NAM BRING PRECIP INTO THE WESTERN END OF THE AREA AS EARLY
AS SATURDAY MORNING. THE LATEST ECMWF MAINTAINS A DRY EASTERLY
FLOW OVER THE REGION A WHILE LONGER AND THUS IS SLOWER WITH THE
PRECIP. WILL TREND TOWARD THIS DRIER AND SLOWER SOLUTION. HAVE
BACKED OFF ON PRECIP CHANCES FOR SATURDAY AND WILL KEEP IT ONLY IN
THE WEST SATURDAY NIGHT. THINK BETTER CHANCES WILL COME AFTER THE
SHORT TERM PERIOD ENDS. TEMPS WILL REMAIN MILD DURING THE PERIOD
AND HAVE USED A BLEND OF GUIDANCE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
STILL HAVE LOW CONFIDENCE IN THE LONG TERM FORECAST AND HAVE MADE
FEW CHANGES. ECMWF LINGERS THE CUTOFF LOW ACROSS THE MID SECTION OF
THE COUNTRY LONGER THAN THE GFS AND THIS SLOWER SOLUTION IS LIKELY
THE BETTER WAY TO GO. THE OTHER PROBLEM LIES WITH THE NORTHERN
STREAM AND THE TIMING OF A TROUGH TO COME DOWN ACROSS THE EASTERN
GREAT LAKES. HPC CONTINUES TO FAVOR THE ECENS FOR ITS SOMEWHAT
BETTER BIG PICTURE CONSISTENCY AND HAVE WEIGHTED THE FORECAST TO THE
OP ECMWF AND HPC/ECENS. THIS IS THE ROUTE WE HAVE BEEN TAKING AND
THEREFORE LITTLE HAS CHANGED TO THE FORECAST.
&&
.AVIATION /17Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1130Z COLD FRONT WAS LOCATED FROM NEAR SANDUSKY TO FINDLAY.
SHOWERS WERE WELL AHEAD OF IT AND WERE ALREADY EXITING EASTERN
TAF SITES. CLEARING MOVING IN QUICKLY SO FIRST QUESTION WILL BE
HOW MUCH PROGRESS WILL IT MAKE. BOTH THE NAM AND THE HRRR GUIDANCE
CLEAR OUT THE LOW CLOUDS QUICKLY THIS MORNING AND HAVE FOLLOWED
THAT BECAUSE WHAT IS ALREADY OCCURRING UPSTREAM. ANOTHER AREA OF
MVFR CEILINGS WERE OVER THE CHICAGO AREA...BUT DO NOT THINK THESE
HAVE MUCH OF ANY CHANCE OF HOLDING TOGETHER TO REACH TOL. SOME
CIRRUS OVERHEAD LATER THIS AFTERNOON. WINDS AFTER THE FRONTAL
PASSAGE WILL BE FROM THE WEST AND WILL LOSE THE GUSTINESS.
DIFFERENCES EXIST ON AVIATION WEATHER FOR TONIGHT INTO THURSDAY.
THERE IS A SOUTHERN SYSTEM TO MOVE ACROSS KY AND THEN THERE WILL
BE A GENERAL TROUGH ALOFT PASSING. GFS LAMP DATA KEPT TODAY CLOUDY
WITH NON VFR CEILINGS AND KEPT THIS OVERNIGHT TOO...AND ACTUALLY
LOWERING TO IFR IN SOME PLACES. NAM GUID NOT SO PESSIMISTIC. WILL
TAKE MIDDLE ROAD FOR NOW AND JUST PUT IN SOME 3500 FT CEILINGS.
.OUTLOOK...NON-VFR CONDITIONS ARE POSSIBLE THURSDAY...LINGERING
ACROSS NE OH/NW PA INTO FRIDAY. NON VFR POSSIBLE AGAIN SUNDAY.
&&
.MARINE...
COLD FRONT TO CROSS THE LAKE THIS MORNING AND SHIFT WINDS TO THE
WEST. WINDS WILL DIMINISH BEHIND THE FRONT. SMALL CRAFT ADVISORY
WILL CONTINUE FOR TODAY FOR THE EAST HALF. HIGH PRESSURE CENTERED TO
THE NORTH OF THE LAKE WILL LARGELY DOMINATE FROM LATER TODAY THROUGH
FRIDAY. FOR THE WEEKEND AND EARLY NEXT WEEK...ONE SYSTEM WILL TRACK
EAST ACROSS THE OHIO VALLEY AND A TROUGH WILL AFFECT THE EASTERN
LAKES...ALTHOUGH FORECAST CONFIDENCE STILL REMAINS LOW FOR NEXT
WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...ADAMS/KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...BC
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
915 AM EST WED FEB 1 2012
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL MOVE EAST OF THE REGION THIS
MORNING. HIGH PRESSURE OVER THE WESTERN GREAT LAKES LATER TODAY
WILL MOVE OVER THE LOCAL AREA BY EARLY FRIDAY. THIS HIGH WILL
SHIFT TO THE EAST COAST BY THE START OF THE WEEKEND BUT MAINTAIN A
RIDGE ACROSS THE UPPER OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LITTLE CHANGE NEEDED TO FORECAST FOR 930 AM UPDATE AS THINGS
REMAIN ON TRACK. DRIER AIR SPREADING IN A MID AND LOW LEVELS WILL
DECREASE CLOUDS INTO EARLY AFTERNOON THEN CIRRUS MOVING IN WILL
PUT A HALF TO THE CLEARING. SOME ADJUSTMENT TO TEMPS AS CURRENT
CONDITIONS WARMER THAN EXPECTED IN THE EAST PART OF THE SNOWBELT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE REMAINDER OF THE
WEEK. AN UPPER WAVE WILL DIVE SE ACROSS THE CENTRAL LAKES ON
THURSDAY. THIS FEATURE WILL BRING SOME MID AND HIGH LEVEL
CLOUDINESS TO THE AREA BUT LOW LEVELS WILL REMAIN TOO DRY FOR ANY
PRECIP CONCERNS. THE HIGH WILL REESTABLISH ITSELF ON FRIDAY AND
FRIDAY NIGHT. THIS WILL RESULT IN MORE PARTLY CLOUDY TO MOSTLY
CLEAR SKIES. MODELS BEGIN TO DIVERGE ON SATURDAY WITH THE LOW
PRESSURE SYSTEM HEADING NE OUT OF THE SOUTHERN PLAINS. THE LATEST
GFS AND NAM BRING PRECIP INTO THE WESTERN END OF THE AREA AS EARLY
AS SATURDAY MORNING. THE LATEST ECMWF MAINTAINS A DRY EASTERLY
FLOW OVER THE REGION A WHILE LONGER AND THUS IS SLOWER WITH THE
PRECIP. WILL TREND TOWARD THIS DRIER AND SLOWER SOLUTION. HAVE
BACKED OFF ON PRECIP CHANCES FOR SATURDAY AND WILL KEEP IT ONLY IN
THE WEST SATURDAY NIGHT. THINK BETTER CHANCES WILL COME AFTER THE
SHORT TERM PERIOD ENDS. TEMPS WILL REMAIN MILD DURING THE PERIOD
AND HAVE USED A BLEND OF GUIDANCE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
STILL HAVE LOW CONFIDENCE IN THE LONG TERM FORECAST AND HAVE MADE
FEW CHANGES. ECMWF LINGERS THE CUTOFF LOW ACROSS THE MID SECTION OF
THE COUNTRY LONGER THAN THE GFS AND THIS SLOWER SOLUTION IS LIKELY
THE BETTER WAY TO GO. THE OTHER PROBLEM LIES WITH THE NORTHERN
STREAM AND THE TIMING OF A TROUGH TO COME DOWN ACROSS THE EASTERN
GREAT LAKES. HPC CONTINUES TO FAVOR THE ECENS FOR ITS SOMEWHAT
BETTER BIG PICTURE CONSISTENCY AND HAVE WEIGHTED THE FORECAST TO THE
OP ECMWF AND HPC/ECENS. THIS IS THE ROUTE WE HAVE BEEN TAKING AND
THEREFORE LITTLE HAS CHANGED TO THE FORECAST.
&&
.AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1130Z COLD FRONT WAS LOCATED FROM NEAR SANDUSKY TO FINDLAY.
SHOWERS WERE WELL AHEAD OF IT AND WERE ALREADY EXITING EASTERN
TAF SITES. CLEARING MOVING IN QUICKLY SO FIRST QUESTION WILL BE
HOW MUCH PROGRESS WILL IT MAKE. BOTH THE NAM AND THE HRRR GUIDANCE
CLEAR OUT THE LOW CLOUDS QUICKLY THIS MORNING AND HAVE FOLLOWED
THAT BECAUSE WHAT IS ALREADY OCCURRING UPSTREAM. ANOTHER AREA OF
MVFR CEILINGS WERE OVER THE CHICAGO AREA...BUT DO NOT THINK THESE
HAVE MUCH OF ANY CHANCE OF HOLDING TOGETHER TO REACH TOL. SOME
CIRRUS OVERHEAD LATER THIS AFTERNOON. WINDS AFTER THE FRONTAL
PASSAGE WILL BE FROM THE WEST AND WILL LOSE THE GUSTINESS.
DIFFERENCES EXIST ON AVIATION WEATHER FOR TONIGHT INTO THURSDAY.
THERE IS A SOUTHERN SYSTEM TO MOVE ACROSS KY AND THEN THERE WILL
BE A GENERAL TROUGH ALOFT PASSING. GFS LAMP DATA KEPT TODAY CLOUDY
WITH NON VFR CEILINGS AND KEPT THIS OVERNIGHT TOO...AND ACTUALLY
LOWERING TO IFR IN SOME PLACES. NAM GUID NOT SO PESSIMISTIC. WILL
TAKE MIDDLE ROAD FOR NOW AND JUST PUT IN SOME 3500 FT CEILINGS.
.OUTLOOK...NON-VFR CONDITIONS ARE POSSIBLE THURSDAY...LINGERING
ACROSS NE OH/NW PA INTO FRIDAY. NON VFR POSSIBLE AGAIN SUNDAY.
&&
.MARINE...
COLD FRONT TO CROSS THE LAKE THIS MORNING AND SHIFT WINDS TO THE
WEST. WINDS WILL DIMINISH BEHIND THE FRONT. SMALL CRAFT ADVISORY
WILL CONTINUE FOR TODAY FOR THE EAST HALF. HIGH PRESSURE CENTERED TO
THE NORTH OF THE LAKE WILL LARGELY DOMINATE FROM LATER TODAY THROUGH
FRIDAY. FOR THE WEEKEND AND EARLY NEXT WEEK...ONE SYSTEM WILL TRACK
EAST ACROSS THE OHIO VALLEY AND A TROUGH WILL AFFECT THE EASTERN
LAKES...ALTHOUGH FORECAST CONFIDENCE STILL REMAINS LOW FOR NEXT
WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...ADAMS/KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
647 AM EST WED FEB 1 2012
.SYNOPSIS...
A COLD FRONT OVER NORTHERN OHIO WILL MOVE EAST OF THE REGION THIS
MORNING. HIGH PRESSURE OVER THE WESTERN GREAT LAKES LATER TODAY
WILL MOVE OVER THE LOCAL AREA BY EARLY FRIDAY. THIS HIGH WILL
SHIFT TO THE EAST COAST BY THE START OF THE WEEKEND BUT MAINTAIN A
RIDGE ACROSS THE UPPER OHIO VALLEY THROUGH SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE UPDATED THE FORECAST FOR CURRENT RADAR AND SATELLITE TRENDS.
THE NW TIP OF THE AREA HAS ALREADY CLEARED. RAPID CLEARING SHOULD
CONTINUE FROM TO WEST TO EAST THIS MORNING. LATEST GUIDANCE
CONTINUES TO SUGGEST THAT THE CLOUDS NEAR CHICAGO AND OVER
NORTHERN LOWER MI SHOULD STAY AWAY TODAY LEAVING ABUNDANT
SUNSHINE. THE REMAINING SHOWERS SHOULD BE GONE BY 13Z.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/...
HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE REMAINDER OF THE
WEEK. AN UPPER WAVE WILL DIVE SE ACROSS THE CENTRAL LAKES ON
THURSDAY. THIS FEATURE WILL BRING SOME MID AND HIGH LEVEL
CLOUDINESS TO THE AREA BUT LOW LEVELS WILL REMAIN TOO DRY FOR ANY
PRECIP CONCERNS. THE HIGH WILL REESTABLISH ITSELF ON FRIDAY AND
FRIDAY NIGHT. THIS WILL RESULT IN MORE PARTLY CLOUDY TO MOSTLY
CLEAR SKIES. MODELS BEGIN TO DIVERGE ON SATURDAY WITH THE LOW
PRESSURE SYSTEM HEADING NE OUT OF THE SOUTHERN PLAINS. THE LATEST
GFS AND NAM BRING PRECIP INTO THE WESTERN END OF THE AREA AS EARLY
AS SATURDAY MORNING. THE LATEST ECMWF MAINTAINS A DRY EASTERLY
FLOW OVER THE REGION A WHILE LONGER AND THUS IS SLOWER WITH THE
PRECIP. WILL TREND TOWARD THIS DRIER AND SLOWER SOLUTION. HAVE
BACKED OFF ON PRECIP CHANCES FOR SATURDAY AND WILL KEEP IT ONLY IN
THE WEST SATURDAY NIGHT. THINK BETTER CHANCES WILL COME AFTER THE
SHORT TERM PERIOD ENDS. TEMPS WILL REMAIN MILD DURING THE PERIOD
AND HAVE USED A BLEND OF GUIDANCE.
&&
.LONG TERM /SUNDAY THROUGH TUESDAY/...
STILL HAVE LOW CONFIDENCE IN THE LONG TERM FORECAST AND HAVE MADE
FEW CHANGES. ECMWF LINGERS THE CUTOFF LOW ACROSS THE MID SECTION OF
THE COUNTRY LONGER THAN THE GFS AND THIS SLOWER SOLUTION IS LIKELY
THE BETTER WAY TO GO. THE OTHER PROBLEM LIES WITH THE NORTHERN
STREAM AND THE TIMING OF A TROUGH TO COME DOWN ACROSS THE EASTERN
GREAT LAKES. HPC CONTINUES TO FAVOR THE ECENS FOR ITS SOMEWHAT
BETTER BIG PICTURE CONSISTENCY AND HAVE WEIGHTED THE FORECAST TO THE
OP ECMWF AND HPC/ECENS. THIS IS THE ROUTE WE HAVE BEEN TAKING AND
THEREFORE LITTLE HAS CHANGED TO THE FORECAST.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
AS OF 1130Z COLD FRONT WAS LOCATED FROM NEAR SANDUSKY TO FINDLAY.
SHOWERS WERE WELL AHEAD OF IT AND WERE ALREADY EXITING EASTERN
TAF SITES. CLEARING MOVING IN QUICKLY SO FIRST QUESTION WILL BE
HOW MUCH PROGRESS WILL IT MAKE. BOTH THE NAM AND THE HRRR GUIDANCE
CLEAR OUT THE LOW CLOUDS QUICKLY THIS MORNING AND HAVE FOLLOWED
THAT BECAUSE WHAT IS ALREADY OCCURRING UPSTREAM. ANOTHER AREA OF
MVFR CEILINGS WERE OVER THE CHICAGO AREA...BUT DO NOT THINK THESE
HAVE MUCH OF ANY CHANCE OF HOLDING TOGETHER TO REACH TOL. SOME
CIRRUS OVERHEAD LATER THIS AFTERNOON. WINDS AFTER THE FRONTAL
PASSAGE WILL BE FROM THE WEST AND WILL LOSE THE GUSTINESS.
DIFFERENCES EXIST ON AVIATION WEATHER FOR TONIGHT INTO THURSDAY.
THERE IS A SOUTHERN SYSTEM TO MOVE ACROSS KY AND THEN THERE WILL
BE A GENERAL TROUGH ALOFT PASSING. GFS LAMP DATA KEPT TODAY CLOUDY
WITH NON VFR CEILINGS AND KEPT THIS OVERNIGHT TOO...AND ACTUALLY
LOWERING TO IFR IN SOME PLACES. NAM GUID NOT SO PESSIMISTIC. WILL
TAKE MIDDLE ROAD FOR NOW AND JUST PUT IN SOME 3500 FT CEILINGS.
.OUTLOOK...NON-VFR CONDITIONS ARE POSSIBLE THURSDAY...LINGERING
ACROSS NE OH/NW PA INTO FRIDAY. NON VFR POSSIBLE AGAIN SUNDAY.
&&
.MARINE...
COLD FRONT TO CROSS THE LAKE THIS MORNING AND SHIFT WINDS TO THE
WEST. WINDS WILL DIMINISH BEHIND THE FRONT. SMALL CRAFT ADVISORY
WILL CONTINUE FOR TODAY FOR THE EAST HALF. HIGH PRESSURE CENTERED TO
THE NORTH OF THE LAKE WILL LARGELY DOMINATE FROM LATER TODAY THROUGH
FRIDAY. FOR THE WEEKEND AND EARLY NEXT WEEK...ONE SYSTEM WILL TRACK
EAST ACROSS THE OHIO VALLEY AND A TROUGH WILL AFFECT THE EASTERN
LAKES...ALTHOUGH FORECAST CONFIDENCE STILL REMAINS LOW FOR NEXT
WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR
LEZ146>149.
&&
$$
SYNOPSIS...KUBINA
NEAR TERM...KUBINA
SHORT TERM...KUBINA
LONG TERM...OUDEMAN
AVIATION...OUDEMAN
MARINE...OUDEMAN
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
103 AM EST WED FEB 1 2012
.SYNOPSIS...
MOISTURE INCREASES RAPIDLY IN THE OHIO VALLEY TONIGHT. WEAK COLD
FRONT WEDNESDAY WITH WAVE WEDNESDAY NIGHT. HIGH PRESSURE THURSDAY
NIGHT INTO FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
UPDATED...
BUMPED THE POPS AHEAD JUST SLIGHTLY AS LINE WAS BARELY OUTRUNNING
THE FORECAST. OTHERWISE...GRIDS ARE IN GOOD SHAPE. WILL BE
WATCHING THE EVOLUTION OF THE SHOWERS BEHIND THIS INITIAL LINE.
PREVIOUS DISCUSSION...
TRACKING AN UPPER LVL WAVE AND S/W TROF AXIS...WELL AHEAD OF SFC
FRONT. MODELS IN GOOD AGREEMENT WITH TIMING AND FORCING WITH THIS.
AS OF 02Z...SEEING SHRA BREAK OUT ACROSS KY INTO CENTRAL OH WITH
HELP OF STRENGTHENING LLJ AND LIFT IN MID LVLS. USED A BLEND OF
CURRENT POP GRIDS WITH HRRR MDL REFLECTIVITY REMAINDER OF NIGHT.
THIS TRACKS BAND OF SHRA THRU CWA...WEAKENING ONCE TO MTNS
PREDAWN. GIVEN AMNT OF DRY AIR IN LLVLS...SOME OF THIS WILL HAVE A
HARD TIME REACHING SFC INITIALLY.
THERE IS SOME MDL DISCREPANCY ON EXTENT OF PROGRESS INTO CWA BY
BAROCLINIC ZONE WEDNESDAY. MAY END UP PARKING IN SE OH OR ALONG OH
RVR WITH SUBSEQUENT SFC WAVE TRAVERSING BOUNDARY WEDNESDAY NIGHT.
DEW POINTS ARE EXPECTED TO INCREASE QUICKLY 00Z TO 06Z IN OUR
OHIO VALLEY COUNTIES AS MOISTURE STREAKS NE...UP THE RIVER VALLEY.
AREAS OF LIGHT RAIN SHOWERS EXPECTED TO DEVELOP INTO SOUTHEAST
OHIO...NORTHEAST KENTUCKY THIS EVENING.
FORECAST PROBLEM...IS HOW FAR EAST AND SOUTH DO THESE SHOWERS GET
LATE TONIGHT AND ON WEDNESDAY...BEFORE THE WEAK WAVE AFFECTS US
WEDNESDAY EVENING.
TRIED TO SLIDE THE LIKELY POP FOR SHOWERS EAST THROUGH CENTRAL WV
05Z TO 09Z...THEN INTO THE CENTRAL MOUNTAINS BEFORE DAWN.
DO NOT HAVE THE SURFACE FRONT INTO SOUTHEAST OHIO UNTIL 18Z
WEDNESDAY THEN TRIED TO HOLD NORTH OF A HTS-CRW LINE AT 00Z. THIS
IS A BIT FURTHER NORTH THAN THE 12Z NAM. SO HAVE POPS DROPPING OFF
A BIT DURING THE MORNING...BEFORE INCREASING AGAIN OVER SOUTHERN
COUNTIES DURING THE AFTERNOON...MAINLY HTS-CRW-EKN ON
SOUTH.
TRIED TO STAY MUCH WARMER THAN 12Z GFS MOS TEMPERATURE MINIMUM
TEMPERATURE GUIDANCE TONIGHT...FIGURING ON INCREASING CLOUD COVER
THIS EVENING.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
MODELS CONTINUE TO STRUGGLE WITH AGREEING ON THE DETAILS OF THE
SYSTEM FOR WEDNESDAY NIGHT INTO THURSDAY. NAM HAS TRENDED MORE
TOWARD THE GFS...BUT THE GFS IS NOT TOTALLY CONSISTENT WITH PREVIOUS
RUNS. CANADIAN DOES NOT DEVELOP THE WAVE MUCH...EXITING IT FAIRLY
FAST. DUE TO ALL THE UNCERTAINTY...WILL STAY TOWARD THE MIDDLE
GROUND FOR NOW.
LOW LEVEL WINDS LOOK TO BE CALM THURSDAY NIGHT. MOS GUIDANCE LOOKS A
BIT HIGH FOR A DECENT RADIATION NIGHT...SO WENT ON THE LOW SIDE OF
GUIDANCE.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
LOTS OF UNCERTAINTY IN THE LONG TERM PERIOD WITH LITTLE MODEL
AGREEMENT. 12Z ECMWF...ALONG WITH ITS 00Z PREDECESSOR...KEEP THE
AREA IN THE NORTHERN BRANCH OF SPLIT FLOW ALOFT OVER THE AREA...THUS
KEEPING A LOW PRESSURE SYSTEM AND ITS ASSOCIATED MOISTURE TO THE
SOUTH AND WEST OF THE AREA OVER THE WEEKEND. CANADIAN AND GFS KEEP
THE AREA IN THE SOUTHERN BRANCH OF THE FLOW...WITH GFS A BIT MORE
AGGRESSIVE WITH THE PROGRESSION OF THE LOW AND MOISTURE INTO OUR
REGION. FOR NOW...FOLLOWED HPC GRAPHICS...WHICH BROAD BRUSH POPS
ACROSS THE AREA...HOWEVER...BEST CHANCE FOR PRECIPITATION AT THIS
POINT DOES APPEAR TO BE THE SOUTHERN ZONES.
DUE TO THE OVERALL UNCERTAINTY...KEPT THE EXTENDED UNSETTLED UNTIL
MID WEEK WHEN HIGH PRESSURE TRIES TO REESTABLISH ITSELF OVER THE
REGION...RESULTING IN DRIER WEATHER.
&&
.AVIATION /05Z WEDNESDAY THROUGH SUNDAY/...
LINE OF SHOWERS WORKING EASTWARD...BUT WILL DO LITTLE TO THE
RESTRICTIONS THIS MORNING. BRIEF MVFR POSSIBLE...BUT WILL COME IN
MORE EFFICIENTLY WITH THE 925-850MB MOISTURE JUST AHEAD OF THE
COLD FRONT AFTER 12Z AND LINGERING THROUGH THE DURATION OF THE TAF
PERIOD. GUSTS TO 20KTS OUR OF THE SOUTHWEST POSSIBLE IN THE
MOUNTAINS.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z THURSDAY...
FORECAST CONFIDENCE: MEDIUM TO HIGH.
ALTERNATE SCENARIOS: TIMING OF RAIN SHOWERS MAY VARY BEHIND THE
INITIAL LINE. MVFR ONSET MAY VARY A COUPLE HOURS.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE WED 02/01/12
UTC 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
EST 1HRLY 01 02 03 04 05 06 07 08 09 10 11 12
CRW CONSISTENCY H H M M H H H H H H M M
HTS CONSISTENCY M M M M H H H H H H M M
BKW CONSISTENCY H H H H H H H M M M M M
EKN CONSISTENCY H H H H M M M H M M M M
PKB CONSISTENCY M M L H H L L M M M M M
CKB CONSISTENCY H M M M L M M H H M M M
AFTER 06Z THURSDAY...
IFR POSSIBLE IN CEILINGS IN LOW LEVEL MOISTURE WEDNESDAY
NIGHT...LINGERING INTO THURSDAY MORNING IN THE MOUNTAINS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...KTB/SL/RPY
NEAR TERM...KTB/26
SHORT TERM...RPY
LONG TERM...SL
AVIATION...26
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
517 AM EST WED FEB 1 2012
.SYNOPSIS...
UNSEASONABLY MILD TEMPERATURES WILL CONTINUE THROUGH THE
WEEK...BEFORE TRENDING BACK TOWARD NORMAL THIS WEEKEND. A WEAK
COLD FRONT WILL PUSH ACROSS TODAY...BRINGING LIGHT RAIN SHOWERS
FOR THE MORNING. A WEAK LOW PRESSURE AREA WILL SLIDE THROUGH THE
MID ATLANTIC STATES TONIGHT...BUT LITTLE OR NO RAIN WILL MAKE IT
NORTH OF THE MASON-DIXON LINE. HIGH PRESSURE WILL RIDGE IN FROM
THE UPPER GREAT LAKES LATE IN THE WEEK. ANOTHER WARM STORM IS
POSSIBLE LATE IN THE WEEKEND OR EARLY NEXT WEEK...BUT UNCERTAINTY
IS HIGH AS A REX BLOCK WILL DEVELOP OVER THE ROCKIES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT OVER LOWER MICHIGAN AND INDIANA WILL MOVE QUICKLY
THROUGH OHIO THIS MORNING AND THROUGH PENNSYLVANIA THIS AFTERNOON.
TWO STRIPES OF LIGHT RAIN SHOWERS EVIDENT ON THE RADAR THIS
MORNING WILL CONTINUE TO SLIDE EASTWARD...WITH THE EASTERN LIFT
WEAKENING VERY QUICKLY. HRRR HAS A GOOD PORTRAYAL OF THE
EVOLUTION OF THE PRECIP THESE LAST FEW HOURS...BUT NOW APPEARS TOO
SLOW IN MOVING THE PRECIP TO THE EAST. WILL HOLD SCT POPS FOR THE
MORNING IN THE EAST...BUT DOWNSLOPING WILL THEN KILL THE PRECIP
BACK CLOSER TO THE FRONT. THE FRONT WILL PASS WITH LITTLE FANFARE
DUE TO THE LOSS OF MOISTURE...MAINLY JUST A GUSTY WIND SHIFT. THE
FRONT WILL SETTLE ALONG A LATITUDE JUST SOUTH OF THE PA BORDER.
TEMPS ARE AGAIN A TOUGH CALL. ABOUT HALF OF THE AREA IN THE 60S
YESTERDAY...AND EARLY MORNING TEMPS ALREADY IN THE 40S...EXCEPT
FOR THE DEEP DARK VALLEY IN WILLIAMSPORT. CALM/LIGHT EASTERLY WIND
THERE INDICATIVE OF COLD AIR DAMMING. BUT AS YESTERDAY PLAYED
OUT...THE MIXING SHOULD EVENTUALLY GET DOWN THAT DEEP AS WELL.
WILL KEEP THE COOLEST MAXES IN THE NW WITH SCT SHRA THERE FOR MOST
OF THE MORNING AND PERHAPS INTO EARLY AFTN UNTIL FROPA...THEN CAA
KEEP THINGS STEADY OR BEGINNING TO FALL A LITTLE. THE REST OF THE
AREA COULD AGAIN TAKE A RUN AT THE M50S-60F. HAVE ONLY DRAWN IN
>60F TEMPS IN THE SERN THIRD OF THE AREA WHERE SKIES SHOULD BECOME
MOSTLY SUNNY THIS AFTERNOON AND DOWNSLOPE WILL HELP THE TEMPS IN
THEIR UNUSUAL CLIMB.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
SFC LOW WAY TO THE NORTH THIS MORNING WILL BE INTO NORTHERN NEW
ENGLAND BY LATE AFTN. THE FRONT WILL LAY OUT TO THE SOUTH OF THE
STATE TONIGHT...AND A SRN STREAM WAVE WILL ROLL UP FROM THE TN
VALLEY ALONG THE FRONT. THE PRECIP WILL HAVE A HARD TIME MAKING IT
NORTHWARD FROM THE GOMEX...AS THE LOW WILL BE CAUGHT IN A FAST
WRLY FLOW ALOFT. A GENERAL BUT ONLY SHORT FALL IN HEIGHTS WILL
HAPPEN AFTER THE LOW PASSES TO THE EAST. LOWS TONIGHT WILL DIP TO
THE M-U20S N AND L-M30S S. WILL CARRY JUST A SLIGHT CHC --RA IN
THE FAR SRN COS TONIGHT.
ALL EYES WILL BE JUST TO THE WEST OF THE CWA ON THURSDAY MORNING.
THE MORNING MAY BE RATHER CLOUDY OVER OUR WESTERN COUNTIES WITH
AN UPSLOPE FLOW INTO THE ALLEGHENIES. DAFFODILS ARE ALREADY
POPPING UP IN MY NEIGHBORS GARDEN DUE TO THE WARM AND WET SEASON
SO FAR. THUS...THE RODENT RUN WITH PERSISTENCE AND TURN A BLIND
EYE TO HIS SHADOW...OR HE MAY AND ARGUE THAT WINTER JUST HAS NOT
SHOWN UP YET AND GET A QUICK GLIMPSE.
IT IS A SAFE BET THAT IT WON/T STAY THIS WARM...BUT IT STILL LOOKS
WARM FOR THURSDAY. TEMPS WILL NOT BE AS LOFTY AS TUESDAY OR
TODAY...BUT WILL STILL BE 5 OR 6 DEGS ABOVE NORMALS AS THE MORNING
CLOUDS WILL DECREASE..ESPECIALLY IN THE EAST. THE CLEARING WILL
OCCUR AS THE LARGE DOME OF HIGH PRESSURE OVER CENTRAL CANADA NOSES
THROUGH THE UPPER GREAT LAKES AND INTO THE STATE. THURSDAY NIGHT
LOWS IN THE TEENS IN THE NORTH AND 20S IN THE S WILL STILL BE 4-6F
ABOVE NORMAL.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE STARTS OUT THE PERIOD IN
REASONABLY GOOD AGREEMENT...SHOWING AN EVOLVING REX BLOCK OVER THE
WEST-CENTRAL CONUS WITH CONFLUENT FLOW DOWNSTREAM IN THE
NORTHEAST. THE ECENS MEAN...AND THE GEFS MEAN TO A SLIGHTLY
LESSER EXTENT...HAVE SHOWN THE STRONGEST CONTINUITY OF THE
GUIDANCE OVER THE PAST SEVERAL MODEL CYCLES. THE MEANS CONTINUE TO
INDICATE THAT THE PRIMARY SYNOPTIC WAVE AFFECTING THE CONTIGUOUS
UNITED STATES WILL MARCH STEADILY ACROSS THE SOUTHERN
PLAINS...LOWER MISSISSIPPI AND TENNESSEE VALLEYS...AND SOUTHEAST
THROUGH THE WEEKEND..WITH HIGH PRESSURE LARGELY DOMINATING THE
WEATHER PATTERN IN THE NORTHEAST STATES. ALTHOUGH FORECASTER
CONFIDENCE HAS SLIGHTLY INCREASED GIVEN THE RELATIVE STABILITY IN
THE PATTERN NOTED IN THE ENSEMBLE DATA...WILL STILL LEAN HEAVILY
TOWARD A 50-50 GUIDANCE COMPROMISE/BLEND FOR SIGNIFICANT WEATHER
ELEMENTS THROUGHOUT THE EXTENDED PERIOD. MORNING PRELIMS WERE
NUDGED TOWARD THE LATER ARRIVING GMOS/HPC DATA.
&&
.AVIATION /10Z WEDNESDAY THROUGH SUNDAY/...
TAFS HOLDING UP WELL. A FEW MINOR CHANGES MADE AT 09Z.
EARLIER DISCUSSION BELOW.
CLEARING SKIES WILL ALLOW FOR TEMPERATURES TO PLUMMET AND THE
INVERSION TO TAKE HOLD...CUTTING OFF THE GUSTY WINDS DUE TO STRONG
FLOW ALOFT.
THE LLWS WILL PERSIST AS THE JET WILL BE AROUND 2000-4000 FT
AROUND 40-50 KTS THROUGH 15Z. MID LEVEL CLOUDS WILL BEGIN TO CREEP
IN FROM THE WEST BEFORE LOW PRESSURE SYSTEM AND THE ASSOCIATED
WEAK COLD FRONT SHOULD SLIDE BY TO OUR NORTH. LIGHT SHOWERS WILL
MOVE IN AFTER 06Z...WITH HIGHEST POPS IN THE NW MTNS TAPERING BACK
TO SCATTERED IN THE CENTRAL AND EAST. MVFR DEVELOPS AT KBFD LATE
TONIGHT...AND COULD SPREAD INTO CENTRAL MTNS BRIEFLY AROUND 12Z.
SHOWERS SHOULD CEASE 15 TO 18Z AS THE FRONT ELONGATES AND EXITS
EARLY TOMORROW AFTERNOON...WHICH SHOULD ALLOW CIGS/VSBY TO IMPROVE
TO VFR AREA-WIDE.
OUTLOOK...
THU...AM FOG POSSIBLE...ESP W MTNS.
FRI-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...CERU/MARTIN/RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
443 AM EST WED FEB 1 2012
.SYNOPSIS...
UNSEASONABLY MILD TEMPERATURES WILL CONTINUE THROUGH THE
WEEK...BEFORE TRENDING BACK TOWARD NORMAL THIS WEEKEND. A WEAK
COLD FRONT WILL PUSH ACROSS TODAY...BRINGING LIGHT RAIN SHOWERS
FOR THE MORNING. A WEAK LOW PRESSURE AREA WILL SLIDE THROUGH THE
MID ATLANTIC STATES TONIGHT...BUT LITTLE OR NO RAIN WILL MAKE IT
NORTH OF THE MASON-DIXON LINE. HIGH PRESSURE WILL RIDGE IN FROM
THE UPPER GREAT LAKES LATE IN THE WEEK. ANOTHER WARM STORM IS
POSSIBLE LATE IN THE WEEKEND OR EARLY NEXT WEEK...BUT UNCERTAINTY
IS HIGH AS A REX BLOCK WILL DEVELOP OVER THE ROCKIES.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A COLD FRONT OVER LOWER MICHIGAN AND INDIANA WILL MOVE QUICKLY
THROUGH OHIO THIS MORNING AND THROUGH PENNSYLVANIA THIS AFTERNOON.
TWO STRIPES OF LIGHT RAIN SHOWERS EVIDENT ON THE RADAR THIS
MORNING WILL CONTINUE TO SLIDE EASTWARD...WITH THE EASTERN LIFT
WEAKENING VERY QUICKLY. HRRR HAS A GOOD PORTRAYAL OF THE
EVOLUTION OF THE PRECIP THESE LAST FEW HOURS...BUT NOW APPEARS TOO
SLOW IN MOVING THE PRECIP TO THE EAST. WILL HOLD SCT POPS FOR THE
MORNING IN THE EAST...BUT DOWNSLOPING WILL THEN KILL THE PRECIP
BACK CLOSER TO THE FRONT. THE FRONT WILL PASS WITH LITTLE FANFARE
DUE TO THE LOSS OF MOISTURE...MAINLY JUST A GUSTY WIND SHIFT. THE
FRONT WILL SETTLE ALONG A LATITUDE JUST SOUTH OF THE PA BORDER.
TEMPS ARE AGAIN A TOUGH CALL. ABOUT HALF OF THE AREA IN THE 60S
YESTERDAY...AND EARLY MORNING TEMPS ALREADY IN THE 40S...EXCEPT
FOR THE DEEP DARK VALLEY IN WILLIAMSPORT. CALM/LIGHT EASTERLY WIND
THERE INDICATIVE OF COLD AIR DAMMING. BUT AS YESTERDAY PLAYED
OUT...THE MIXING SHOULD EVENTUALLY GET DOWN THAT DEEP AS WELL.
WILL KEEP THE COOLEST MAXES IN THE NW WITH SCT SHRA THERE FOR MOST
OF THE MORNING AND PERHAPS INTO EARLY AFTN UNTIL FROPA...THEN CAA
KEEP THINGS STEADY OR BEGINNING TO FALL A LITTLE. THE REST OF THE
AREA COULD AGAIN TAKE A RUN AT THE M50S-60F. HAVE ONLY DRAWN IN
>60F TEMPS IN THE SERN THIRD OF THE AREA WHERE SKIES SHOULD BECOME
MOSTLY SUNNY THIS AFTERNOON AND DOWNSLOPE WILL HELP THE TEMPS IN
THEIR UNUSUAL CLIMB.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
SFC LOW WAY TO THE NORTH THIS MORNING WILL BE INTO NORTHERN NEW
ENGLAND BY LATE AFTN. THE FRONT WILL LAY OUT TO THE SOUTH OF THE
STATE TONIGHT...AND A SRN STREAM WAVE WILL ROLL UP FROM THE TN
VALLEY ALONG THE FRONT. THE PRECIP WILL HAVE A HARD TIME MAKING IT
NORTHWARD FROM THE GOMEX...AS THE LOW WILL BE CAUGHT IN A FAST
WRLY FLOW ALOFT. A GENERAL BUT ONLY SHORT FALL IN HEIGHTS WILL
HAPPEN AFTER THE LOW PASSES TO THE EAST. LOWS TONIGHT WILL DIP TO
THE M-U20S N AND L-M30S S. WILL CARRY JUST A SLIGHT CHC --RA IN
THE FAR SRN COS TONIGHT.
ALL EYES WILL BE JUST TO THE WEST OF THE CWA ON THURSDAY MORNING.
THE MORNING MAY BE RATHER CLOUDY OVER OUR WESTERN COUNTIES WITH
AN UPSLOPE FLOW INTO THE ALLEGHENIES. DAFFODILS ARE ALREADY
POPPING UP IN MY NEIGHBORS GARDEN DUE TO THE WARM AND WET SEASON
SO FAR. THUS...THE RODENT RUN WITH PERSISTENCE AND TURN A BLIND
EYE TO HIS SHADOW...OR HE MAY AND ARGUE THAT WINTER JUST HAS NOT
SHOWN UP YET AND GET A QUICK GLIMPSE.
IT IS A SAFE BET THAT IT WON/T STAY THIS WARM...BUT IT STILL LOOKS
WARM FOR THURSDAY. TEMPS WILL NOT BE AS LOFTY AS TUESDAY OR
TODAY...BUT WILL STILL BE 5 OR 6 DEGS ABOVE NORMALS AS THE MORNING
CLOUDS WILL DECREASE..ESPECIALLY IN THE EAST. THE CLEARING WILL
OCCUR AS THE LARGE DOME OF HIGH PRESSURE OVER CENTRAL CANADA NOSES
THROUGH THE UPPER GREAT LAKES AND INTO THE STATE. THURSDAY NIGHT
LOWS IN THE TEENS IN THE NORTH AND 20S IN THE S WILL STILL BE 4-6F
ABOVE NORMAL.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
MEDIUM RANGE MODEL AND ENSEMBLE GUIDANCE STARTS OUT THE PERIOD IN
REASONABLY GOOD AGREEMENT...SHOWING AN EVOLVING REX BLOCK OVER THE
WEST-CENTRAL CONUS WITH CONFLUENT FLOW DOWNSTREAM IN THE
NORTHEAST. THE ECENS MEAN...AND THE GEFS MEAN TO A SLIGHTLY
LESSER EXTENT...HAVE SHOWN THE STRONGEST CONTINUITY OF THE
GUIDANCE OVER THE PAST SEVERAL MODEL CYCLES. THE MEANS CONTINUE TO
INDICATE THAT THE PRIMARY SYNOPTIC WAVE AFFECTING THE CONTIGUOUS
UNITED STATES WILL MARCH STEADILY ACROSS THE SOUTHERN
PLAINS...LOWER MISSISSIPPI AND TENNESSEE VALLEYS...AND SOUTHEAST
THROUGH THE WEEKEND..WITH HIGH PRESSURE LARGELY DOMINATING THE
WEATHER PATTERN IN THE NORTHEAST STATES. ALTHOUGH FORECASTER
CONFIDENCE HAS SLIGHTLY INCREASED GIVEN THE RELATIVE STABILITY IN
THE PATTERN NOTED IN THE ENSEMBLE DATA...WILL STILL LEAN HEAVILY
TOWARD A 50-50 GUIDANCE COMPROMISE/BLEND FOR SIGNIFICANT WEATHER
ELEMENTS THROUGHOUT THE EXTENDED PERIOD. MORNING PRELIMS WERE
NUDGED TOWARD THE LATER ARRIVING GMOS/HPC DATA.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
A FEW SHOWERS ACROSS THE SOUTH...STILL GOOD VISIBILITY AND
CIGS FOR THE MOST PART.
EARLIER DISCUSSION BELOW.
CLEARING SKIES WILL ALLOW FOR TEMPERATURES TO PLUMMET AND THE
INVERSION TO TAKE HOLD...CUTTING OFF THE GUSTY WINDS DUE TO STRONG
FLOW ALOFT.
THE LLWS WILL PERSIST AS THE JET WILL BE AROUND 2000-4000 FT
AROUND 40-50 KTS THROUGH 15Z. MID LEVEL CLOUDS WILL BEGIN TO CREEP
IN FROM THE WEST BEFORE LOW PRESSURE SYSTEM AND THE ASSOCIATED
WEAK COLD FRONT SHOULD SLIDE BY TO OUR NORTH. LIGHT SHOWERS WILL
MOVE IN AFTER 06Z...WITH HIGHEST POPS IN THE NW MTNS TAPERING BACK
TO SCATTERED IN THE CENTRAL AND EAST. MVFR DEVELOPS AT KBFD LATE
TONIGHT...AND COULD SPREAD INTO CENTRAL MTNS BRIEFLY AROUND 12Z.
SHOWERS SHOULD CEASE 15 TO 18Z AS THE FRONT ELONGATES AND EXITS
EARLY TOMORROW AFTERNOON...WHICH SHOULD ALLOW CIGS/VSBY TO IMPROVE
TO VFR AREA-WIDE.
OUTLOOK...
THU...AM FOG POSSIBLE...ESP W MTNS.
FRI-SUN...NO SIG WX EXPECTED.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO/LA CORTE
NEAR TERM...DANGELO
SHORT TERM...DANGELO
LONG TERM...STEINBUGL
AVIATION...CERU/MARTIN/RXR
AREA FORECAST DISCUSSION...UPDATED
NWS FORT WORTH TX
923 AM CST WED FEB 1 2012
.UPDATE...
DENSE FOG IS LIFTING AND VISIBILITIES ARE IMPROVING ACROSS NORTH
TEXAS THIS MORNING SO HAVE LET THE DENSE FOG ADVISORY EXPIRE.
WATER VAPOR SHOWS UPPER LEVEL DISTURBANCE MOVING THROUGH THE
SOUTHERN PLAINS THIS MORNING. UPWARD FORCING FROM THIS FEATURE IS
HELPING TO RESULT IN A FEW ELEVATED SHOWERS AND THUNDERSTORMS
ACROSS PARTS OF OKLAHOMA AND NORTH TEXAS. THE 12Z FWD SOUNDING
INDICATED STEEP MID LEVEL LAPSE RATES WHICH WILL CONTINUE TO
SUPPORT THUNDERSTORMS THROUGH EARLY AFTERNOON. WITH CONTINUED
HEATING SOME SURFACE BASED STORMS MAY BE POSSIBLE BY EARLY
AFTERNOON MAINLY ACROSS THE NORTHEASTERN COUNTIES BEFORE THE
SYSTEM MOVES TO THE EAST OF THE AREA AND LARGE SCALE SUBSIDENCE
MOVES IN. WILL LEAVE 20 POPS IN ACROSS THE CENTRAL AND EASTERN
PART OF THE CWA THROUGH THIS AFTERNOON.
DUNN
&&
.AVIATION...
FOR THE 12Z TAFS...FOG AND LOW STRATUS IN THE FIRST FEW HOURS OF
THE VALID FORECAST PERIOD ARE THE PRIMARY CONCERNS. VFR CONDITIONS
ARE EXPECTED FROM LATE THIS MORNING THRU THE END OF THE FORECAST
PERIOD.
AREAS OF DENSE FOG HAD DEVELOPED ACROSS THE EASTERN HALF OF NORTH
TEXAS EARLY THIS MORNING. THE WORST OF THE FOG WAS RELEGATED TO
KGKY FOR METROPLEX TAF SITES AND KACT REMAINS SOCKED IN WITH 1/4
MILE FOG AT THE TIME OF THIS DISCUSSION. EXPECT IFR CONDITIONS TO
PERSIST AT KGKY THRU 14Z WHEN VEERING WINDS AND THE APPROACH OF A
WEAK COLD FRONT SHOULD BE SUFFICIENT TO DISSIPATE LOWER VSBYS IN
SOUTHERN TARRANT COUNTY. IFR CONDITIONS ARE LIKELY TO PERSIST AT
KACT THRU AT LEAST 15Z. DID NOT EXTEND FLIGHT RESTRICTIONS BEYOND
15Z AT THIS TIME AS KACT REMAINS ON THE WESTERN PERIPHERY OF THE
BANK OF DENSE FOG AND THEREFORE CAN BE EXPECTED TO RESPOND QUICKLY
TO HEATING AFTER SUNRISE. A WEAK FRONTAL BOUNDARY IS EXPECTED TO
PUSH THROUGH NORTH TX A BIT FASTER THAN PREVIOUS FORECAST
INDICATED. LATEST RUC GUIDANCE BRINGS THE FRONT THRU THE METROPLEX
DURING THE EARLY AFTERNOON HRS AND THEN THRU WACO AROUND 21Z.
DRIER AIR BEHIND THE FRONT SHOULD ENSURE VFR CONDITIONS FOR THE
NEXT 24 HRS AT AREA TAF SITES.
CANNOT RULE OUT SOME RAIN SHOWER OR ISOLATED TSTM ACTIVITY ALONG
THE COLD FRONT THIS AFTERNOON. DO NOT HAVE ANY MENTION OF
PRECIPITATION IN THE TAFS AT THIS TIME AS COVERAGE IS EXPECTED TO
BE LIMITED DUE TO MEAGER FORCING FOR ASCENT ALONG THE COLD FRONT.
WILL MONITOR FOR SIGNS OF DEVELOPMENT AND AMEND TAFS IF NECESSARY
THIS MORNING.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 514 AM CST WED FEB 1 2012/
SHALLOW DENSE FOG DEVELOPED IN THE NEAR-CALM SURFACE LAYER.
ADVISORY COVERS MUCH OF THE AREA WHERE PATCHY DENSE FOG
PERSISTS...BUT SOME SHALLOW FOG WILL CONTINUE ELSEWHERE.
TODAY...
DIFFUSE FRONTAL BOUNDARY REMAINS NEAR NORTHWESTERN EDGE OF CWA.
DESPITE ORIENTATION OF EARLY MORNING CONVECTION...FLOW WITHIN THE
LAYER OF LIFT IS PARALLEL TO THE BOUNDARY. THIS AREA OF RATHER
BENIGN CONVECTION WILL SLOWLY TRANSLATE NORTHEAST INTO NE ZONES
OVER THE COURSE OF THE DAY. FRONT WILL PENETRATE CWA TODAY...AND
THE BOUNDARY WILL INTERACT WITH UNSEASONABLY WARM BOUNDARY LAYER.
AS WINDS PICK UP...THE 60F ISODROSOTHERM WILL MOVE FARTHER
INLAND...RESULTING IN MUCAPE VALUES IN EXCESS OF 1000 J/KG. BUT
WITH MINIMAL LOW-LEVEL CONVERGENCE AND RATHER SHALLOW MOISTURE...
HAVE LOW CONFIDENCE IN WIDESPREAD CONVECTION THIS AFTERNOON. WITH
MESOSCALE MODELS RATHER GUN-SHY...WILL MAINTAIN 20 POPS IN
EAST/SOUTHEAST ZONES.
FRIDAY EVENT...
TROUGH CURRENTLY OVER THE ALEUTIANS WILL QUICKLY DEEPEN AS IT
ENTRAINS BITTER COLD FROM THE POLAR VORTEX NEAR THE ARCTIC COAST
OF ALASKA. THE RESULTING DOWNSTREAM RIDGE WILL PUSH THE TROUGH
CURRENTLY NEAR THE WEST COAST OF THE CONUS EASTWARD. THE
AMPLIFICATION OF THE RIDGE AS IT REACHES THE WEST COAST WILL ALLOW
THIS TROUGH TO PULL POLAR AIR INTO THE INTERMOUNTAIN WEST...
DEEPENING THE FEATURE INTO A CLOSED LOW AS EARLY AS THURSDAY.
WARM ADVECTION AHEAD OF THE SYSTEM MAY ALLOW SOME SHOWERS
(ISOLATED THUNDER) TO DEVELOP LATE THURSDAY. THE UPGLIDE WILL
INCREASE DRAMATICALLY THURSDAY NIGHT...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS LIKELY BY DAYBREAK FRIDAY. SIGNIFICANT FORCING WILL
MEAN STRONG CONVECTION COULD ACCOMPANY FROPA LATE FRIDAY...BUT
STILL HAVE CONCERNS THAT PRECIP EARLY IN THE DAY WILL LIMIT
INSTABILITY FOR THE MAIN EVENT. WHILE THERE IS GOOD INTER-MODEL
AGREEMENT INTO FRIDAY ON THE SYNOPTIC SCALE AS GUIDANCE IS ABLE TO
RESOLVE A WELL BEHAVED SYSTEM WITHIN THE POLAR STREAM...IT IS TOO
EARLY TO PERFECT PROG THE MESOSCALE EVOLUTION OF THE EVENT.
WEEKEND...
BY FRIDAY NIGHT...THE POLAR JET CUTS THE LOW OFF...AND SOLUTIONS
DIVERGE AS A RESULT. DESPITE SOME UNCERTAINTY IN FRONTAL TIMING...
WILL CONTINUE TO TAPER OFF POPS FRIDAY NIGHT. TEMPS CLOSER TO
NORMAL WILL PREVAIL THIS WEEKEND. ONCE LOW FINALLY EJECTS...A
REINFORCING SHOT OF COLD AIR WILL INVADE SATURDAY NIGHT AND
SUNDAY. SOME MOIST UPGLIDE WILL BY POSSIBLE EARLY SUNDAY IN
SOUTHERN ZONES...BUT EXPECT THE THIN MOISTURE TO ONLY YIELD A
CLOUD LAYER. MEX GUIDANCE APPEARS TOO BULLISH...WILL MAINTAIN POP-
FREE FORECAST BEYOND FRIDAY NIGHT.
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 75 52 72 61 74 / 20 10 10 50 80
WACO, TX 74 50 72 59 75 / 20 10 10 50 80
PARIS, TX 70 52 68 58 72 / 20 10 10 50 80
DENTON, TX 72 45 70 58 73 / 20 10 10 50 80
MCKINNEY, TX 72 45 69 56 74 / 20 10 10 50 80
DALLAS, TX 73 53 72 61 75 / 20 10 10 50 80
TERRELL, TX 73 52 72 60 73 / 20 10 10 50 80
CORSICANA, TX 75 55 76 61 74 / 20 10 20 50 80
TEMPLE, TX 77 52 75 59 73 / 10 10 10 50 70
MINERAL WELLS, TX 72 44 69 56 71 / 20 10 10 50 80
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
601 AM CST WED FEB 1 2012
.AVIATION...
FOR THE 12Z TAFS...FOG AND LOW STRATUS IN THE FIRST FEW HOURS OF
THE VALID FORECAST PERIOD ARE THE PRIMARY CONCERNS. VFR CONDITIONS
ARE EXPECTED FROM LATE THIS MORNING THRU THE END OF THE FORECAST
PERIOD.
AREAS OF DENSE FOG HAD DEVELOPED ACROSS THE EASTERN HALF OF NORTH
TEXAS EARLY THIS MORNING. THE WORST OF THE FOG WAS RELEGATED TO
KGKY FOR METROPLEX TAF SITES AND KACT REMAINS SOCKED IN WITH 1/4
MILE FOG AT THE TIME OF THIS DISCUSSION. EXPECT IFR CONDITIONS TO
PERSIST AT KGKY THRU 14Z WHEN VEERING WINDS AND THE APPROACH OF A
WEAK COLD FRONT SHOULD BE SUFFICIENT TO DISSIPATE LOWER VSBYS IN
SOUTHERN TARRANT COUNTY. IFR CONDITIONS ARE LIKELY TO PERSIST AT
KACT THRU AT LEAST 15Z. DID NOT EXTEND FLIGHT RESTRICTIONS BEYOND
15Z AT THIS TIME AS KACT REMAINS ON THE WESTERN PERIPHERY OF THE
BANK OF DENSE FOG AND THEREFORE CAN BE EXPECTED TO RESPOND QUICKLY
TO HEATING AFTER SUNRISE. A WEAK FRONTAL BOUNDARY IS EXPECTED TO
PUSH THROUGH NORTH TX A BIT FASTER THAN PREVIOUS FORECAST
INDICATED. LATEST RUC GUIDANCE BRINGS THE FRONT THRU THE METROPLEX
DURING THE EARLY AFTERNOON HRS AND THEN THRU WACO AROUND 21Z.
DRIER AIR BEHIND THE FRONT SHOULD ENSURE VFR CONDITIONS FOR THE
NEXT 24 HRS AT AREA TAF SITES.
CANNOT RULE OUT SOME RAIN SHOWER OR ISOLATED TSTM ACTIVITY ALONG
THE COLD FRONT THIS AFTERNOON. DO NOT HAVE ANY MENTION OF
PRECIPITATION IN THE TAFS AT THIS TIME AS COVERAGE IS EXPECTED TO
BE LIMITED DUE TO MEAGER FORCING FOR ASCENT ALONG THE COLD FRONT.
WILL MONITOR FOR SIGNS OF DEVELOPMENT AND AMEND TAFS IF NECESSARY
THIS MORNING.
CAVANAUGH
&&
.PREV DISCUSSION... /ISSUED 514 AM CST WED FEB 1 2012/
SHALLOW DENSE FOG DEVELOPED IN THE NEAR-CALM SURFACE LAYER.
ADVISORY COVERS MUCH OF THE AREA WHERE PATCHY DENSE FOG
PERSISTS...BUT SOME SHALLOW FOG WILL CONTINUE ELSEWHERE.
TODAY...
DIFFUSE FRONTAL BOUNDARY REMAINS NEAR NORTHWESTERN EDGE OF CWA.
DESPITE ORIENTATION OF EARLY MORNING CONVECTION...FLOW WITHIN THE
LAYER OF LIFT IS PARALLEL TO THE BOUNDARY. THIS AREA OF RATHER
BENIGN CONVECTION WILL SLOWLY TRANSLATE NORTHEAST INTO NE ZONES
OVER THE COURSE OF THE DAY. FRONT WILL PENETRATE CWA TODAY...AND
THE BOUNDARY WILL INTERACT WITH UNSEASONABLY WARM BOUNDARY LAYER.
AS WINDS PICK UP...THE 60F ISODROSOTHERM WILL MOVE FARTHER
INLAND...RESULTING IN MUCAPE VALUES IN EXCESS OF 1000 J/KG. BUT
WITH MINIMAL LOW-LEVEL CONVERGENCE AND RATHER SHALLOW MOISTURE...
HAVE LOW CONFIDENCE IN WIDESPREAD CONVECTION THIS AFTERNOON. WITH
MESOSCALE MODELS RATHER GUN-SHY...WILL MAINTAIN 20 POPS IN
EAST/SOUTHEAST ZONES.
FRIDAY EVENT...
TROUGH CURRENTLY OVER THE ALEUTIANS WILL QUICKLY DEEPEN AS IT
ENTRAINS BITTER COLD FROM THE POLAR VORTEX NEAR THE ARCTIC COAST
OF ALASKA. THE RESULTING DOWNSTREAM RIDGE WILL PUSH THE TROUGH
CURRENTLY NEAR THE WEST COAST OF THE CONUS EASTWARD. THE
AMPLIFICATION OF THE RIDGE AS IT REACHES THE WEST COAST WILL ALLOW
THIS TROUGH TO PULL POLAR AIR INTO THE INTERMOUNTAIN WEST...
DEEPENING THE FEATURE INTO A CLOSED LOW AS EARLY AS THURSDAY.
WARM ADVECTION AHEAD OF THE SYSTEM MAY ALLOW SOME SHOWERS
(ISOLATED THUNDER) TO DEVELOP LATE THURSDAY. THE UPGLIDE WILL
INCREASE DRAMATICALLY THURSDAY NIGHT...WITH WIDESPREAD SHOWERS AND
THUNDERSTORMS LIKELY BY DAYBREAK FRIDAY. SIGNIFICANT FORCING WILL
MEAN STRONG CONVECTION COULD ACCOMPANY FROPA LATE FRIDAY...BUT
STILL HAVE CONCERNS THAT PRECIP EARLY IN THE DAY WILL LIMIT
INSTABILITY FOR THE MAIN EVENT. WHILE THERE IS GOOD INTER-MODEL
AGREEMENT INTO FRIDAY ON THE SYNOPTIC SCALE AS GUIDANCE IS ABLE TO
RESOLVE A WELL BEHAVED SYSTEM WITHIN THE POLAR STREAM...IT IS TOO
EARLY TO PERFECT PROG THE MESOSCALE EVOLUTION OF THE EVENT.
WEEKEND...
BY FRIDAY NIGHT...THE POLAR JET CUTS THE LOW OFF...AND SOLUTIONS
DIVERGE AS A RESULT. DESPITE SOME UNCERTAINTY IN FRONTAL TIMING...
WILL CONTINUE TO TAPER OFF POPS FRIDAY NIGHT. TEMPS CLOSER TO
NORMAL WILL PREVAIL THIS WEEKEND. ONCE LOW FINALLY EJECTS...A
REINFORCING SHOT OF COLD AIR WILL INVADE SATURDAY NIGHT AND
SUNDAY. SOME MOIST UPGLIDE WILL BY POSSIBLE EARLY SUNDAY IN
SOUTHERN ZONES...BUT EXPECT THE THIN MOISTURE TO ONLY YIELD A
CLOUD LAYER. MEX GUIDANCE APPEARS TOO BULLISH...WILL MAINTAIN POP-
FREE FORECAST BEYOND FRIDAY NIGHT.
25
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 75 52 72 61 74 / 10 10 10 50 80
WACO, TX 74 50 72 59 75 / 10 10 10 50 80
PARIS, TX 70 52 68 58 72 / 20 10 10 50 80
DENTON, TX 72 45 70 58 73 / 20 10 10 50 80
MCKINNEY, TX 72 45 69 56 74 / 20 10 10 50 80
DALLAS, TX 73 53 72 61 75 / 10 10 10 50 80
TERRELL, TX 73 52 72 60 73 / 20 10 10 50 80
CORSICANA, TX 75 55 76 61 74 / 20 10 20 50 80
TEMPLE, TX 77 52 75 59 73 / 10 10 10 50 70
MINERAL WELLS, TX 72 44 69 56 71 / 20 10 10 50 80
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR TXZ094-095-
104>107-120>123-133>135-145>148-158>162-174-175.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
311 PM CST WED FEB 1 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY
311 PM CST WED FEB 1 2012
MAIN FORECAST CONCERNS ARE CLOUDS AND FOG TRENDS THIS
EVENING/TONIGHT...THEN PRECIPITATION CHANCES AND TYPES FRIDAY NIGHT
INTO SATURDAY.
LATEST VISIBLE SATELLITE IMAGERY SHOWING LOW STRATUS/DENSE FOG
BEGINNING TO DIMINISH ACROSS THE UPPER GREAT LAKES REGION. LATEST
20Z METARS ARE INDICATING VISIBILITIES IMPROVING OVER PORTIONS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA.
THE 01.12Z DETERMINISTIC GFS/NAM ARE IN DECENT AGREEMENT WITH
OVERALL UPPER LEVEL AND SURFACE FEATURES THROUGH 00Z SATURDAY.
THEN...BEGIN TO DIVERGE SLIGHTLY ON TIMING AND PLACEMENT OF UPPER
LEVEL/SURFACE LOW INTO THE GREAT LAKES REGION AFTER 00Z SATURDAY.
ANOTHER SIGNIFICANT DIFFERENCE OCCURS AFTER 00Z SATURDAY...AS THE
01.12Z NAM IS COOLER ON NORTHERN PERIPHERY OF UPPER
LEVEL/SURFACE LOW PER BUFKIT SOUNDINGS THAN THE GFS. THIS WILL HAVE
IMPACTS ON PRECIPITATION TYPE FRIDAY NIGHT AND INTO SATURDAY.
TONIGHT...WITH LOW STRATUS AND DENSE FOG DIMINISHING ACROSS
FORECAST AREA...WILL CANCEL DENSE FOG ADVISORY ACROSS PORTIONS OF
SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THE LATEST 01.12Z GFS/NAM
AND 01.15Z RUC INDICATE INVERSION TO SET UP OVER THE FORECAST AREA
THIS EVENING. WITH ABUNDANT BOUNDARY LAYER MOISTURE...DUE TO CLOUD
COVER DURING THE DAY. HAVE INTRODUCED AREAS OF FOG TONIGHT INTO
THURSDAY MORNING ACROSS FORECAST AREA.
ALL THE 01.12Z DETERMINISTIC MODELS ARE CARVING TROUGH AND CUTTING
OFF UPPER LEVEL LOW OVER THE WESTERN UNITED STATES THURSDAY NIGHT
INTO FRIDAY...THEN SLOWLY LIFT UPPER LEVEL LOW INTO THE UPPER
MIDWEST AND GREAT LAKES REGION FRIDAY NIGHT INTO SATURDAY. THE
MODELS DO INDICATE DECENT ISENTROPIC LIFT AT 290K SURFACE AND DEEP QG
FORCING OVER PORTIONS OF NORTHEAST IOWA AND SOUTHWEST WISCONSIN.
THIS WILL SPREAD A BAND OF PRECIPITATION INTO THIS AREA AFTER 06Z
SATURDAY. THE LATEST 01.12Z DETERMINISTIC GFS/NAM DO INDICATE
TEMPERATURES BELOW OR NEAR FREEZING THROUGH THE ATMOSPHERE
COLUMN FRIDAY NIGHT INTO SATURDAY PER BUFKIT SOUNDINGS. HOWEVER...THE
LATEST 01.12Z ECMWF IS MUCH FARTHER WEST WITH THE 850MB LOW AND
ADVECTS SLIGHTLY WARMER AIR NORTHWARD INTO THE REGION. UNCERTAINTIES
EXIST AS TOO HOW MUCH WARM AIR ADVECTS NORTHWARD INTO THE REGION
FRIDAY NIGHT INTO SATURDAY. FOR NOW...HAVE KEPT MAINLY ALL SNOW FROM
06Z THROUGH 18Z SATURDAY...AND A RAIN/SNOW MIX AFTER 18Z SATURDAY
ACROSS MUCH OF THE SOUTHERN HALF OF FORECAST AREA. SIGNIFICANT
SNOW ACCUMULATION WILL DEPEND ON THE EXACT TRACK OF THE UPPER
LEVEL/SURFACE LOW AND THE TEMPERATURES THROUGH THE ATMOSPHERE COLUMN
FRIDAY NIGHT INTO SATURDAY.
.LONG TERM...SATURDAY NIGHT THROUGH WEDNESDAY
311 PM CST WED FEB 1 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES SATURDAY NIGHT
INTO SUNDAY. THE 01.12Z GFS/ECMWF/GEM CONTINUE TO BE
DIFFERENT IN TIMING AND PLACEMENT OF UPPER LEVEL LOW SLOWLY LIFTING
NORTHEASTWARD INTO THE UPPER GREAT LAKES AND UPPER MIDWEST
SATURDAY NIGHT INTO SUNDAY NIGHT. THE MODELS DO SUGGEST THE
PRECIPITATION IN ASSOCIATION WITH THE UPPER LEVEL LOW WILL BE
CONFINED MAINLY OVER THE SOUTHERN HALF OF THE FORECAST AREA SATURDAY
NIGHT INTO SUNDAY. AS FAR AS PRECIPITATION TYPES...THE 01.12Z GFS
BUFKIT SOUNDINGS DO INDICATE SNOW MAINLY AT NIGHT AND A MIXTURE OF
RAIN AND SNOW DURING THE DAY. AFTER 12Z MONDAY...THE DETERMINISTIC
GEM/GFS/ECMWF ARE IN MUCH BETTER AGREEMENT WITH BUILDING SURFACE
RIDGE INTO THE NORTHERN PLAINS AND THE UPPER MIDWEST. DRY WEATHER
CONDITIONS AND SEASONABLE TEMPERATURES CAN BE EXPECTED ACROSS THE
FORECAST AREA TUESDAY INTO MIDDLE OF NEXT WEEK.
&&
.AVIATION...THROUGH 18Z THURSDAY
1204 PM CST WED FEB 1 2012
WITH THE GFS AND RUC MODEL SOUNDINGS CONTINUING TO SUGGEST THAT
THE LOW LEVEL INVERSION WILL REMAIN IN PLACE THROUGH 02.03Z.
EXTENDED THE DENSE FOG AT KRST THROUGH THIS TIME PERIOD...AND THEN
WENT WITH A GRADUAL IMPROVEMENT IN BOTH VISIBILITIES AND CEILINGS.
MEANWHILE AT KLSE...STILL NOT QUITE SURE WHETHER THE DENSE FOG
WILL MOVE INTO THIS AREA. THE MODELS SUGGEST THAT THIS MAY MOVE
MORE NORTHEAST AND BE FOUND MAINLY ALONG AND NORTH OF THE
INTERSTATE 94 CORRIDOR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
311 PM CST WED FEB 1 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION.....BOYNE
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
228 PM CST WED FEB 1 2012
.SHORT TERM...TONIGHT AND THURSDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW LOW PRESSURE
OVER SOUTHERN QUEBEC AND A LARGE HIGH PRESSURE SYSTEM STRETCHING
FROM THE SOUTHERN PLAINS INTO THE WESTERN GREAT LAKES. WIDESPREAD
1-2KFT STRATUS EXISTS ACROSS MUCH OF THE WESTERN AND CENTRAL GREAT
LAKES EARLY THIS AFTERNOON...THOUGH EVEN LOWER CEILINGS AND FOG
EXIST BACK TO THE NORTHERN MISSISSIPPI VALLEY. MEANWHILE FARTHER
UPSTREAM...A WEAK SHORTWAVE TROUGH IS DIVING SE OVER THE ND/MANITOBA
BORDER. NOT MUCH PRECIP ACTIVITY WITH THIS WAVE...BUT AS IT TRACKS
TOWARDS NORTHERN WISCONSIN TONIGHT...LIGHT SNOW CHANCES AS WELL AS
CLOUD COVER ARE THE MAIN FORECAST CONCERNS.
TONIGHT...BROAD HIGH PRESSURE OVER THE PLAINS WILL DRIFT
EAST OVER THE WESTERN GREAT LAKES TONIGHT...WHILE A WEAK SHEARED
SHORTWAVE TROUGH DIVES SOUTH OVER NORTHERN WISCONSIN. FORCING IS
PRETTY WEAK WITH THIS WAVE AND MID-LEVELS STRUGGLE TO SATURATE.
STILL THOUGH...DEWPOINT DEPRESSIONS ARE LOW ENOUGH TO WARRANT AT
LEAST FLURRIES OVER NORTHERN WISCONSIN AFTER MIDNIGHT...AND WILL
KEEP A TENTH OR TWO OF ACCUMS ALONG THE U.P. BORDER.
OTHERWISE...THE LIGHT WIND REGIME AND AMPLE MOISTURE STUCK BENEATH
THE BL INVERSION ARE SUPPORTIVE OF THE LOW STRATUS STICKING AROUND
ALL NIGHT LONG. IF HOLES IN THE CLOUDS OCCUR...THEN FOG WOULD
DEVELOP. SO WENT PESSIMISTIC WITH CLOUD COVER FOR THIS FORECAST.
LOWS WILL ONLY FALL A FEW DEGREES WITH THE CLOUD COVER.
THURSDAY...THE SHORTWAVE TROUGH WILL EXIT NE WISCONSIN DURING THE
MORNING AND WILL LEAVE A CHANCE OF FLURRIES IN THE FORECAST.
OTHERWISE...PACIFIC HIGH PRESSURE WILL STICK AROUND THE REGION.
925MB TEMPS DO WARM A FEW DEGREES OVER CENTRAL AND EAST-CENTRAL
WISCONSIN IN THE AFTERNOON. SO WILL SHOW WIDESPREAD LOW STRATUS IN
THE MORNING ERODING THERE FIRST TOMORROW AFTERNOON. TEMPS REMAIN
DIFFICULT PENDING POTENTIAL SUNSHINE AND WILL GO UPPER 30S NORTH TO
MIDDLE 40S SOUTH.
.LONG TERM...THU NGT THRU NXT WED. SPLIT FLOW REMAINS THE RULE
ACROSS THE CONUS DURING THE EXTENDED PART OF THE FCST. ONLY REAL
PBLM TO BE THE EVENTUAL MOVEMENT OF A MODEST CLOSED UPR LOW DURING
THE SUNDAY/MON TIME PERIOD. MDLS HAVE DRIFTED THIS SYSTEM FARTHER
NORTH (ESP THE ECMWF/UKMET) WHICH WOULD NOW BRING A CHC OF PCPN TO
PARTS OF THE FCST AREA. ONCE THIS SYSTEM DEPARTS..A BRIEF SHOT OF
COOLER AIR OVERSPREADS THE GREAT LKS...BUT ONLY APRS TO BE A BLIP
ON THIS WARM WINTER AS TEMPS LOOK TO WARM AGAIN LATER NXT WEEK.
HI PRES TO STRETCH FROM SRN SASKATCHEWAN EWD INTO WRN ONTARIO...
COUPLED WITH ANOTHER HI PRES OVER WRN PA...WL KEEP THE TRANQUIL
WEATHER GOING THU NGT. THERE IS A WEAK THERMAL TROF AT THE SFC
OVER NRN SECTIONS OF THE GREAT LKS WHICH WOULD KEEP MORE CLOUDS
OVER NRN WI THAN CNTRL/E-CNTRL WI. HOWEVER...TIME SECTIONS/FCST
SNDNGS INDICATE THAT MSTR JUST ABV THE SFC MAY BE TRAPPED BLO AN
INVERSION...THUS MOSTLY CLOUDY SKIES EXPECTED THROUGHOUT ALL OF NE
WI. MIN TEMPS WL BE HELD UP BY THESE CLOUDS AND FAVOR THE WARMER
SIDE OF GUIDANCE.
ATTENTION TURNS TOWARD THE CNTRL CONUS AS A CLOSED UPR LOW EXITS
THE ROCKIES AND MOVES INTO THE CNTRL PLAINS ON FRI. INCREASING
SOUTHERLY WINDS ARE EXPECTED TO BEGIN DRAWING GULF MSTR NWD THRU
THE OZARKS INTO THE MID-MS VALLEY WITH SHWRS/TSTMS BREAKING OUT.
MEANWHILE...HI PRES TO EXTEND FROM THE NRN PLAINS EAST THRU NRN
SECTIONS OF THE GREAT LKS AND PROVIDE A DRY EASTERLY FLOW INTO WI.
MAY STILL BE DEALING WITH LINGERING LOW CLOUDS WHICH WOULD PUT A
CRIMP ON MAX TEMPS. FOR NOW...HAVE TEMPERED READINGS DOWN A DEGREE
OR TWO FROM THE PREV FCST...BUT STILL WELL-ABOVE NORMAL.
AS THE UPR LOW SLOWLY TRUDGES ACROSS THE CNTRL PLAINS FRI NGT...
GULF MSTR WL MAKE A SURGE NORTH TOWARD THE GREAT LKS THANKS TO A
50 KT SW LOW-LVL JET. THE AREA OF HI PRES REMAINS ANCHORED OVER
NRN SECTIONS OF THE GREAT LKS...THUS SETTING UP A BATTLE BETWEEN
THE ENTRENCHED DRY AIR AND INCOMING MSTR. HAVE KEPT NRN WI PARTLY
CLOUDY WITH PARTLY TO MOSTLY CLOUDY SKIES FOR CNTRL/E-CNTRL WI.
THIS SET-UP WOULD PROVIDE FOR A WIDE RANGE IN TEMPS WITH THE NORTH
FALLING INTO THE LOWER TO MIDDLE TEENS...WHILE THE LAKESHORE AREAS
ONLY DIP INTO THE MIDDLE TO UPPER 20S. THE CLOSED UPR LOW IS FCST
TO MOVE E-NE INTO THE MIDWEST (VCNTY SRN IA) ON SAT. SOUTHERLY
WINDS OVERRUNNING A WRMFNT STRETCHED FROM THE MIDWEST E-SE INTO
THE OHIO RIVER VALLEY...WL BEGIN TO SPREAD CLOUDS NWD INTO WI BY
SAT AFTERNOON. STILL EXPECT A NICE DAY ACROSS NE WI WITH MAX TEMPS
A GOOD 10 TO 15 DEGS ABV NORMAL.
MDL INCONSISTENTCY PERSISTS WITH THE HANDLING OF THE SYSTEM HEADED
INTO SUNDAY AND THIS RESULTS IN POTENTIALLY SIGNIFICANT SENSIBLE
WEATHER DIFFERENCES FOR THE FCST AREA. IF THIS SYSTEM TRACKS NE...
IT WOULD BRING A LGT SNOW OR SNOW/RAIN THREAT TO MUCH OF NE WI. AN
EWD TRACK WOULD ONLY BRUSH CNTRL/E-CNTRL WI WITH PERHAPS A DUSTING
TO A COUPLE TENTHS OF AN INCH OF SNOW. PREFER TO TAKE A CAUTIOUS
APPROACH HERE UNTIL THE MDLS SETTLE DOWN AND WL ONLY MENTION A SML
POP GENERALLY ALONG/SOUTH OF A MFI-SUE LINE. SML POPS WOULD THEN
BE NEEDED INTO SUNDAY NGT AS THE SYSTEM EITHER MOVES INTO NRN OR
SRN SECTIONS OF THE GREAT LKS RGN. SOME EVIDENCE OF IMPROVING
CONDITIONS FOR MON AS THE SYSTEM PULLS AWAY WITH A WEAK UPR RDG
SLIDING INTO WI. MAX TEMPS TO REMAIN WELL ABV NORMAL WITH PLENTY
OF MIDDLE TO UPPER 30S EXPECTED.
A SECONDARY CDFNT DROPS SWD THRU WI MON NGT...BUT MDLS VARY AS TO
THE EXTENT OF THE COLD AIR TO FILTER INTO THE RGN. THE 12Z ECMWF
HAS BACKED OFF QUITE A BIT WITH 8H TEMPS FALLING INTO THE LOWER TO
MIDDLE TEENS BLO ZERO (COMPARED TO -20C ON ITS PREV RUN). THE GFS
IS COMPARABLE WITH ITS PREV RUN WITH 8H TEMPS AROUND -10C. BASED
ON THE SPLIT FLOW PATN...WL LEAN TOWARD THE GFS SOLN WHICH KEEPS
TEMPS ABV NORMAL THRU TUE. WL NEED TO WATCH FOR POTENTIAL OF LK
EFFECT SNOW SHOWERS FOR VILAS CNTY MON NGT INTO TUE AS TRAJS BECOME
FAVORABLE. HAVE ADDED A SML CHC POP THERE FOR NOW. OTHERWISE...HI
PRES TO START BUILDING EWD FROM THE NRN PLAINS AND KEEP THE REST
OF NE WI ON THE QUIET SIDE. THIS BROAD/STRONG AREA OF HI PRES
SETTLES SOUTH AND EAST ACROSS THE CNTRL CONUS BY NXT WED AND WL
CONT TO PROVIDE DRY CONDITIONS TO NE WI. ANY LK EFFECT ACROSS
VILAS CNTY WL CEASE AS DRIER AIR ADVECTS INTO THE RGN. EVEN THO
TEMPS MAY COOL A BIT...ANTICIPATE READINGS TO REMAIN ABOUT 5 DEGS
ABV NORMAL FOR EARLY FEB.
&&
.AVIATION...
LOW STRATUS AND FOG CONTINUE TO WREAK HAVOC ON FORECASTS OVER THE
WESTERN GREAT LAKES. SATELLITE IMAGERY DOESNT GIVE MUCH HOPE FOR
CLEARING THROUGH MIDDAY TOMORROW AS THE STRATUS AND FOG REMAIN PLACE
BACK TO MINNESOTA AND IOWA. HIGH PRESSURE WILL BUILD INTO THE REGION
TONIGHT LEAVING LIGHT WINDS IN PLACE. BOUNDARY LAYER TEMPS WARM A
COUPLE DEGREES TONIGHT WHICH WOULD HELP DISSIPATE THE CLOUDS...BUT
THE LIGHT WINDS AND HIGH DEWPOINTS WOULD ONLY PROMOTE FOG FORMATION.
AS A RESULT...SHOW LOWERING CIGS AND VSBYS LATE TONIGHT INTO
TOMORROW MORNING...WHICH HAS BEEN THE TREND UPSTREAM THE PAST COUPLE
DAYS. WILL HAVE A WEAK UPPER LEVEL DISTURBANCE BRING A CHANCE OF
FLURRIES TO NORTHERN WISCONSIN BUT NOT CONFIDENT TO ADD SNOW TO RHI
AT THIS TIME.
MPC
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
MPC/KALLAS
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1212 PM CST WED FEB 1 2012
.SHORT TERM...THIS AFTERNOON AND EVENING
1204 PM CST WED FEB 1 2012
GFS AND RUC MODEL SOUNDINGS CONTINUE TO SHOW THAT A STRONG
SUBSIDENCE INVERSION WILL ALLOW LITTLE MIXING TO TAKE PLACE ACROSS
SOUTHEAST MINNESOTA AND NORTHEAST IOWA THROUGH AT LEAST 9 PM
TONIGHT. DUE TO THIS...EXTENDED THE DENSE FOG ADVISORY THROUGH
9 PM TONIGHT. AFTER WARDS IT APPEARS THAT A 925 MB FRONT WILL MOVE
EAST THROUGH THE AREA. THE GFS SOUNDINGS SUGGEST THAT THE WINDS
WILL INCREASE INTO THE 5 TO 10 KNOT RANGE AND THE LOW LEVEL
MOISTURE WILL SCOUR OUT. WITH ROAD TEMPERATURES GENERALLY IN THE
32 TO 34 DEGREE RANGE...NOT OVERLY CONCERNED ABOUT WIDESPREAD
BLACK ICING. HOWEVER WITH THE SURFACE TEMPERATURES BELOW FREEZING
DECIDED TO MENTION THAT THERE MAY BE A POSSIBILITY FOR SOME PATCHY
BLACK ICE.
WITH THE EXTENSIVE CLOUDS AND LITTLE WARM AIR ADVECTION...LOWERED
TEMPERATURES A FEW MORE DEGREES WITH THE LATEST UPDATE.
.LONG TERM...SATURDAY THROUGH TUESDAY
320 AM CST WED FEB 1 2012
01.00Z MEDIUM RANGE MODEL CONSENSUS SLOWLY IMPROVING IN THE DAY 4-7
TIME-FRAME...BUT STILL PLENTY OF DIFFERENCES AND POOR RUN-TO-RUN
CONSISTENCY BY SAT. MODEL DIFFERENCES RESULT IN SIGNIFICANT
SENSIBLE WEATHER DIFFERENCES FOR PARTS OR ALL OF THE FCST AREA
SAT/SUN. INTERESTING THAT GFS WITH THE MOST NORTHERLY SOLUTION OF
THE 31.00Z RUNS IS NOW THE MORE SOUTHERLY SOLUTION. THE ECMWF HAS
FLIPPED THESE ROLES TOO AND IS NOW ONE OF THE MORE NORTHERLY
SOLUTIONS. NEEDLESS TO SAY...FCST CONFIDENCE BY SAT/SUN ON THE LOW
SIDE. GIVEN THE FLIP-FLOPPING OF THE MODELS AND BELOW AVERAGE RUN-
TO-RUN CONSISTENCY...NOT WILLING TO POINT TO ANY ONE DETERMINISTIC
MODEL AS A PREFERRED CHOICE FOR THE UPCOMING WEEKEND. USED THE
MODEL/ENSEMBLE CONSENSUS FOR SAT/SUN...WITH 20 TO 40 PERCENT SNOW OR
-RA/-SN CHANCES...HIGHEST ACROSS THE SOUTH END OF THE FCST AREA.
MON/TUE TREND DRY WITH A DRIER WEST/NORTHWEST FLOW SPREADING ACROSS
THE UPPER MIDWEST. HOWEVER CONFIDENCE NOT HIGH HERE EITHER WITH
OUTCOME OF SAT/SUN TO WEIGH INTO FLOW EVOLUTION FOR EARLY NEXT
WEEK...AND MODELS SHOWING POTENTIAL FOR A NORTHWEST FLOW SHORTWAVE
OR TWO TO DROP INTO/ACROSS THE REGION. BETTER CONFIDENCE FOR TEMPS
TO REMAIN ABOVE NORMAL FOR SAT-TUE WITH ARCTIC AIR REMAINING WELL
NORTH IN CANADA.
&&
.AVIATION...THROUGH 18Z THURSDAY
1204 PM CST WED FEB 1 2012
WITH THE GFS AND RUC MODEL SOUNDINGS CONTINUING TO SUGGEST THAT
THE LOW LEVEL INVERSION WILL REMAIN IN PLACE THROUGH 02.03Z.
EXTENDED THE DENSE FOG AT KRST THROUGH THIS TIME PERIOD...AND THEN
WENT WITH A GRADUAL IMPROVEMENT IN BOTH VISIBILITIES AND CEILINGS.
MEANWHILE AT KLSE...STILL NOT QUITE SURE WHETHER THE DENSE FOG
WILL MOVE INTO THIS AREA. THE MODELS SUGGEST THAT THIS MAY MOVE
MORE NORTHEAST AND BE FOUND MAINLY ALONG AND NORTH OF THE
INTERSTATE 94 CORRIDOR.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1204 PM CST WED FEB 1 2012
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 9 PM CST THIS EVENING FOR MNZ079-
086>088-094>096.
IA...DENSE FOG ADVISORY UNTIL 9 PM CST THIS EVENING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...BOYNE
LONG TERM....RRS
AVIATION...BOYNE
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1020 AM CST WED FEB 1 2012
.AVIATION/18Z TAFS/...THE BACK EDGE OF THE STRATUS...CURRENTLY
OVER NORTHWEST IOWA... SOUTHWEST MINNESOTA AND NORTHEAST NORTH
DAKOTA...ISN/T SHOWING MUCH...IF ANY...PROGRESSION EASTWARD. WITH
LIGHT WINDS AND NO REAL CLEARING MECHANISM...THE CLOUDS WILL
LIKELY STICK AROUND THROUGH THE EVENING HOURS...AND POSSIBLY INTO
TOMORROW. THE QUESTION IS JUST WHEN THE CLOUDS WILL MOVE OUT OF
THE AREA. ALSO...DENSE FOG JUST TO THE WEST OF THE
MISSISSIPPI...IN NORTHEAST IOWA AND SOUTHEAST MINNESOTA...IS
HOLDING STRONG. VISIBILITIES IN THIS AREA ARE DOWN TO A QUARTER OF
A MILE. IF MORE PREVALENT WESTERLY WINDS DEVELOP THIS AFTERNOON WE
COULD SEE THAT FOG MAKE IT ACROSS THE MISSISSIPPI AND INTO SOUTH
CENTRAL WISCONSIN. THE PROGS DO IN FACT SHOW 1000-925 MILLIBAR
WINDS BECOMING MORE WESTERLY INTO TONIGHT...SO VSBYS SUGGESTED
MET/MAV GUIDANCE MAY BE TOO OPTIMISTIC TONIGHT INTO THURSDAY
MORNING.
MEB/PC
&&
.PREV DISCUSSION... /ISSUED 327 AM CST WED FEB 1 2012/
TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
WEAK COLD AIR ADVECTION STRATUS HAS SETTLED OVER SRN WI DURING
THE NIGHT. TAMDAR ASCENT SOUNDINGS FROM KMSP CONFIRM 00Z KMPX
SOUNDING SHOWING CLOUDS ABOUT 500-1000FT THICK...WITH SOME OF THE
MOISTURE IN AS WELL AS BELOW THE SUBSIDENCE INVERSION WITH DRIER
AIR ALOFT. UPSTREAM LOW LEVEL FLOW WEAK VCNTY OF LOW LEVEL RIDGING
AND BACK EDGE OF LOW CLOUDS IN WRN MN NOT MAKING MUCH EWD PROGRESS
LAST FEW HOURS. 06Z NAM TRIES TO BREAK UP/THIN RH LATER THIS MRNG
OVER PORTIONS OF SRN WI WHILE RUC IS LESS OPTIMISTIC.
NOT SEEING MUCH SUBSIDENCE ALOFT ASSOCD WITH ANY SYNOPTIC FEATURE
TO HELP SCOUR LOW CLOUDS...AND WEAK UPSTREAM SHORT WAVE OVER ERN
DAKOTAS DOES BRING IN MID/HIGH CLOUDS LATER TODAY. WITH WEAK COLD
AIR ADVECTION CONTINUING THIS MRNG AND LIGHTER FLOW IN THE LOW
LEVELS SETTLING IN...WL BE MORE PESSIMISTIC WITH CLOUDS FOR TODAY.
SECOND SLIGHTLY STRONGER MID-LEVEL WAVE WL BRING MORE MID/HIGH
CLOUDS INTO THE AREA TONIGHT...AND VERY POSSIBLE THAT LOW CLOUDS
WILL STILL BE HANGING AROUND SRN WI.
HWVR...WL NEED TO WATCH FOR WEAK TERRAIN INDUCED SUBSIDENCE
HELPING TO THIN THE CLOUDS IN THE FAR ERN CWA LATER THIS MRNG AND
AFTN. NEVER THE LESS...WITH CLOUDY TO M/CLOUDY CONDITIONS EXPCD
TODAY AND W-NW SFC WNDS...KEPT TEMPS IN CHECK...CLOSER TO COOLER
MET GUIDANCE. DESPITE EXPCD CLOUD COVER TONIGHT...LIGHT BOUNDARY
LAYER WINDS SHOULD ALLOW AT LEAST PATCHY FOG TO DEVELOP.
SHORT TERM...THURSDAY THROUGH FRIDAY NIGHT...FORECAST CONFIDENCE
MEDIUM TO HIGH.
WEAK HIGH PRESSURE WILL SLOWLY MOVE EAST ACROSS THE REGION
THURSDAY AND THURSDAY NIGHT...BRINGING QUIET WEATHER TO THE AREA.
SOME MIDDLE OR HIGH CLOUDS MAY MOVE THROUGH THE AREA AT TIMES.
LIGHT WINDS AND LOW LEVEL MOISTURE THURSDAY NIGHT MAY LEAD TO SOME
FOG FORMATION...BUT MODELS HAVE BEEN OVERESTIMATING LOW LEVEL
MOISTURE QUITE A BIT THIS WINTER...SO WILL NOT MENTION IN FORECAST
YET. MILD TEMPERATURES WILL CONTINUE...WELL ABOVE SEASONAL
NORMALS.
LARGER HIGH PRESSURE ACROSS THE FAR NORTHERN PLAINS FRIDAY WILL
KEEP THE AREA DRY...WITH ANOTHER MILD DAY EXPECTED UNDER PARTLY
SUNNY SKIES.
LEE CYCLOGENESIS OCCURS IN THE SOUTHERN HIGH PLAINS THURSDAY NIGHT
INTO FRIDAY...AS AN UPPER LOW DEVELOPS ACROSS THE SOUTHERN ROCKIES
AND SHIFTS INTO THE SOUTHERN HIGH PLAINS. THE NAM/GFS/CANADIAN
MODELS ARE QUICKER WITH THE PROGRESSION OF THIS SYSTEM TO THE EAST
ACROSS THE CENTRAL PLAINS THAN THE ECMWF. THE ECMWF DEVELOPS A
DEEP CUTOFF LOW OVER NORTH CENTRAL KANSAS BY 12Z SATURDAY...WITH A
DEEP SURFACE LOW JUST TO THE EAST.
THE OTHER MODELS HAVE THE UPPER LOW ANYWHERE FROM SOUTH CENTRAL
KANSAS TO FAR SOUTHWEST IOWA...WITH THE SURFACE LOW ANYWHERE FROM
NORTHERN TO SOUTHWESTERN MISSOURI. GIVEN THE CONFIDENCE HPC HAS
HAD WITH THE ECMWF AND ECMWF ENSEMBLES WITH THIS SYSTEM...LEANED
TOWARDS IT AND KEPT MOST OF THE AREA DRY FRIDAY NIGHT. KEPT LOW
POPS IN THE FAR SOUTHWEST LATE FRIDAY NIGHT FOR CONTINUITY...BUT
MAY HAVE TO TAKE THESE OUT IN LATER FORECASTS IF SLOWER ECMWF
VERIFIES.
LONG TERM...SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE LOW.
MAJOR DIFFERENCES EXIST DURING THIS PERIOD BETWEEN THE ECMWF AND
GFS. THE GFS CONTINUES TO BE MORE PROGRESSIVE WITH THE UPPER LOW
SATURDAY INTO SATURDAY NIGHT...TAKING IT ACROSS SOUTHERN IOWA AND
CENTRAL ILLINOIS. ASSOCIATED SURFACE LOW MOVES QUICKLY EAST FROM
CENTRAL MISSOURI TO KENTUCKY. THIS TRACK BRINGS PRECIPITATION INTO
THE AREA SATURDAY INTO SATURDAY EVENING.
THE ECMWF REMAINS SLOWER AND DEEPER WITH THE UPPER LOW DURING THIS
TIME...KEEPING IT ACROSS THE CENTRAL PLAINS. SURFACE LOW OCCLUDES
AS IT BECOMES VERTICALLY STACKED WITH THE UPPER LOW. THIS SCENARIO
ALSO BRINGS LIGHT PRECIPITATION INTO MAINLY SOUTHERN PORTIONS OF
THE AREA. WILL CONTINUE TO USE CONSENSUS POPS AND TEMPERATURES FOR
THIS PERIOD...THOUGH WOULD LEAN MORE TOWARD THE SLOWER LOOK OF THE
ECMWF.
ECMWF TAKES UPPER LOW AND DEVELOPS AN OPEN WAVE OUT OF IT SUNDAY
NIGHT THROUGH MONDAY AS IT MOVES EAST THROUGH THE REGION. IT DOES
BRING LIGHT PRECIPITATION ACROSS THE AREA WITH IT. THE GFS IS DRY
WITH HIGH PRESSURE ACROSS THE AREA DURING THIS TIME. THEY BOTH
GENERALLY SHOW SOME COLD AIR ADVECTION LATER MONDAY INTO
TUESDAY...WITH THE ECMWF SHOWING STRONG COLD AIR ADVECTION TUESDAY
WITH A SHARP UPPER TROUGH MOVING THROUGH THE REGION. THE GFS IS
MUCH WEAKER WITH THE COLD ADVECTION. WILL CONTINUE TO USE
CONSENSUS POPS AND TEMPERATURES DURING THIS TIME. MILD
TEMPERATURES SHOULD CONTINUE DESPITE THE MODEL DIFFERENCES.
AVIATION/12Z TAFS/...
MVFR CIGS HAVE ENGULFED ALL OF SRN WI EARLY THIS MRNG. WILL
CONTINUE MVFR CIGS INTO THE AFTN...WITH LIGHTER WINDS IN WRN CWA
POSSIBLY ALLOWING CIGS TO FALL INTO IFR CATEGORY FOR A TIME AT
KMSN. FOR NOW WL TREND TOWARD CLOUDS THINNING THIS AFTN...BUT
CONFIDENCE LOW DUE TO ABOVE DISCUSSION. LIGHTER BOUNDARY LAYER
WINDS AND LINGERING LOW LEVEL MOISTURE SHOULD ALLOW PATCHY FOG TO
DEVELOP TONIGHT.
MARINE...
NORTHWEST WINDS WILL CONTINUE TO DIMINISH THIS MORNING AS THE
PRESSURE GRADIENT FURTHER WEAKENS. LIGHT WIND CONDITIONS ARE THEN
EXPECTED FOR AN EXTENDED PERIOD OF TIME FROM TONIGHT THROUGH
FRIDAY...UNTIL LOW PRESSURE BEGINS TO STRENGTHEN OVER THE CENTRAL
PLAINS AND MEANDER EWD OVER THE WEEKEND.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
THURSDAY THROUGH TUESDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
549 AM CST WED FEB 1 2012
.SHORT TERM...
549 AM CST WED FEB 1 2012
AS THE SURFACE WINDS HAVE CONTINUED TO SLOWLY DIMINISH THROUGH THE
NIGHT...THE VISIBILITY HAS SLOWLY GONE DOWN AS WELL. VISIBILITIES
ACROSS MUCH OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA HAVE GONE
DOWN TO A HALF MILE OR LESS. WITH AIR TEMPERATURES BELOW
FREEZING...THE FOG MAY BE DEPOSITING A THIN LAYER OF ICE ON ANY
UNTREATED SURFACES. THE 01.09Z RUC REALLY DOES NOT SHOW ANY
SIGNIFICANT IMPROVEMENT POSSIBLE THROUGH MUCH OF THE MORNING. THE
STRATUS DECK ABOVE THE FOG IS EXPECTED TO REMAIN IN PLACE AND THE
WINDS WILL REMAIN LIGHT. TEMPERATURES MAY GET ABOVE FREEZING BY
LATE MORNING TO ELIMINATE THE ICING THREAT...BUT CONCERNED THE
VISIBILITY MAY NOT IMPROVE MUCH UNTIL AFTERNOON. HAVE COORDINATED
AN ENDING TIME OF A DENSE FOG ADVISORY WITH SURROUNDING
OFFICES...BUT WOULD NOT BE SURPRISED IF THIS HAS TO BE EXTENDED.
.LONG TERM...SATURDAY THROUGH TUESDAY
320 AM CST WED FEB 1 2012
01.00Z MEDIUM RANGE MODEL CONSENSUS SLOWLY IMPROVING IN THE DAY 4-7
TIME-FRAME...BUT STILL PLENTY OF DIFFERENCES AND POOR RUN-TO-RUN
CONSISTENCY BY SAT. MODEL DIFFERENCES RESULT IN SIGNIFICANT
SENSIBLE WEATHER DIFFERENCES FOR PARTS OR ALL OF THE FCST AREA
SAT/SUN. INTERESTING THAT GFS WITH THE MOST NORTHERLY SOLUTION OF
THE 31.00Z RUNS IS NOW THE MORE SOUTHERLY SOLUTION. THE ECMWF HAS
FLIPPED THESE ROLES TOO AND IS NOW ONE OF THE MORE NORTHERLY
SOLUTIONS. NEEDLESS TO SAY...FCST CONFIDENCE BY SAT/SUN ON THE LOW
SIDE. GIVEN THE FLIP-FLOPPING OF THE MODELS AND BELOW AVERAGE RUN-
TO-RUN CONSISTENCY...NOT WILLING TO POINT TO ANY ONE DETERMINISTIC
MODEL AS A PREFERRED CHOICE FOR THE UPCOMING WEEKEND. USED THE
MODEL/ENSEMBLE CONSENSUS FOR SAT/SUN...WITH 20 TO 40 PERCENT SNOW OR
-RA/-SN CHANCES...HIGHEST ACROSS THE SOUTH END OF THE FCST AREA.
MON/TUE TREND DRY WITH A DRIER WEST/NORTHWEST FLOW SPREADING ACROSS
THE UPPER MIDWEST. HOWEVER CONFIDENCE NOT HIGH HERE EITHER WITH
OUTCOME OF SAT/SUN TO WEIGH INTO FLOW EVOLUTION FOR EARLY NEXT
WEEK...AND MODELS SHOWING POTENTIAL FOR A NORTHWEST FLOW SHORTWAVE
OR TWO TO DROP INTO/ACROSS THE REGION. BETTER CONFIDENCE FOR TEMPS
TO REMAIN ABOVE NORMAL FOR SAT-TUE WITH ARCTIC AIR REMAINING WELL
NORTH IN CANADA.
&&
.AVIATION...TODAY AND TONIGHT
549 AM CST WED FEB 1 2012
WHEN AND IF THE STRATUS DECK WILL LEAVE THE AREA IS THE BIG
QUESTION. THE WESTERN EDGE OF THE STRATUS AT THIS POINT IS JUST
AHEAD OF A WEAK 925 MB TROUGH AXIS OVER THE EASTERN DAKOTAS. THE
01.06Z NAM AND 01.09Z RUC SUGGEST THIS TROUGH AXIS AND THUS THE
MOISTURE FIELD WILL NOT PASS EAST OF THE TAF SITES UNTIL THIS
EVENING. HAVE PUSHED BACK THE CLEARING TRENDS FOR BOTH TAF SITES
UNTIL THE MID EVENING AND THEN CONCERNED THAT THIS MAY BE TOO
SOON. THE VISIBILITY AT KRST IS ALSO NOT EXPECTED TO IMPROVE VERY
FAST TODAY. HAVE KEPT THE VISIBILITY BELOW A MILE THROUGH THE
MORNING AND THEN BROUGHT IT UP TO IFR WITH A SLIGHT WIND SHIFT TO
THE SOUTHWEST AS THE TROUGH AXIS STARTS TO APPROACH. IF THIS BATCH
OF STRATUS CAN CLEAR OUT THIS EVENING...CONCERNED THAT THE
VISIBILITY COULD GO BACK DOWN TO MVFR OR IFR AGAIN WITH DECENT
RADIATIONAL COOLING CONDITIONS. INCLUDED THIS POSSIBILITY AT BOTH
TAF SITES AND IF THE INVERSION DOES NOT GET MIXED OUT BEHIND THE
PASSAGE OF THE TROUGH AXIS...COULD SEE THE STRATUS REDEVELOPING
AGAIN AS THE AIR BEGINS TO COOL.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
549 AM CST WED FEB 1 2012
WI...NONE.
MN...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR MNZ079-
086>088-094>096.
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ008>011-
018-019-029-030.
&&
$$
SHORT TERM...04
LONG TERM....RRS
AVIATION...04
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
327 AM CST WED FEB 1 2012
.TODAY AND TONIGHT...FORECAST CONFIDENCE LOW TO MEDIUM.
WEAK COLD AIR ADVECTION STRATUS HAS SETTLED OVER SRN WI DURING
THE NIGHT. TAMDAR ASCENT SOUNDINGS FROM KMSP CONFIRM 00Z KMPX
SOUNDING SHOWING CLOUDS ABOUT 500-1000FT THICK...WITH SOME OF THE
MOISTURE IN AS WELL AS BELOW THE SUBSIDENCE INVERSION WITH DRIER
AIR ALOFT. UPSTREAM LOW LEVEL FLOW WEAK VCNTY OF LOW LEVEL RIDGING
AND BACK EDGE OF LOW CLOUDS IN WRN MN NOT MAKING MUCH EWD PROGRESS
LAST FEW HOURS. 06Z NAM TRIES TO BREAK UP/THIN RH LATER THIS MRNG
OVER PORTIONS OF SRN WI WHILE RUC IS LESS OPTIMISTIC.
NOT SEEING MUCH SUBSIDENCE ALOFT ASSOCD WITH ANY SYNOPTIC FEATURE
TO HELP SCOUR LOW CLOUDS...AND WEAK UPSTREAM SHORT WAVE OVER ERN
DAKOTAS DOES BRING IN MID/HIGH CLOUDS LATER TODAY. WITH WEAK COLD
AIR ADVECTION CONTINUING THIS MRNG AND LIGHTER FLOW IN THE LOW
LEVELS SETTLING IN...WL BE MORE PESSIMISTIC WITH CLOUDS FOR TODAY.
SECOND SLIGHTLY STRONGER MID-LEVEL WAVE WL BRING MORE MID/HIGH
CLOUDS INTO THE AREA TONIGHT...AND VERY POSSIBLE THAT LOW CLOUDS
WILL STILL BE HANGING AROUND SRN WI.
HWVR...WL NEED TO WATCH FOR WEAK TERRAIN INDUCED SUBSIDENCE
HELPING TO THIN THE CLOUDS IN THE FAR ERN CWA LATER THIS MRNG AND
AFTN. NEVER THE LESS...WITH CLOUDY TO M/CLOUDY CONDITIONS EXPCD
TODAY AND W-NW SFC WNDS...KEPT TEMPS IN CHECK...CLOSER TO COOLER
MET GUIDANCE. DESPITE EXPCD CLOUD COVER TONIGHT...LIGHT BOUNDARY
LAYER WINDS SHOULD ALLOW AT LEAST PATCHY FOG TO DEVELOP.
.SHORT TERM...THURSDAY THROUGH FRIDAY NIGHT...FORECAST CONFIDENCE
MEDIUM TO HIGH.
WEAK HIGH PRESSURE WILL SLOWLY MOVE EAST ACROSS THE REGION
THURSDAY AND THURSDAY NIGHT...BRINGING QUIET WEATHER TO THE AREA.
SOME MIDDLE OR HIGH CLOUDS MAY MOVE THROUGH THE AREA AT TIMES.
LIGHT WINDS AND LOW LEVEL MOISTURE THURSDAY NIGHT MAY LEAD TO SOME
FOG FORMATION...BUT MODELS HAVE BEEN OVERESTIMATING LOW LEVEL
MOISTURE QUITE A BIT THIS WINTER...SO WILL NOT MENTION IN FORECAST
YET. MILD TEMPERATURES WILL CONTINUE...WELL ABOVE SEASONAL
NORMALS.
LARGER HIGH PRESSURE ACROSS THE FAR NORTHERN PLAINS FRIDAY WILL
KEEP THE AREA DRY...WITH ANOTHER MILD DAY EXPECTED UNDER PARTLY
SUNNY SKIES.
LEE CYCLOGENESIS OCCURS IN THE SOUTHERN HIGH PLAINS THURSDAY NIGHT
INTO FRIDAY...AS AN UPPER LOW DEVELOPS ACROSS THE SOUTHERN ROCKIES
AND SHIFTS INTO THE SOUTHERN HIGH PLAINS. THE NAM/GFS/CANADIAN
MODELS ARE QUICKER WITH THE PROGRESSION OF THIS SYSTEM TO THE EAST
ACROSS THE CENTRAL PLAINS THAN THE ECMWF. THE ECMWF DEVELOPS A
DEEP CUTOFF LOW OVER NORTH CENTRAL KANSAS BY 12Z SATURDAY...WITH A
DEEP SURFACE LOW JUST TO THE EAST.
THE OTHER MODELS HAVE THE UPPER LOW ANYWHERE FROM SOUTH CENTRAL
KANSAS TO FAR SOUTHWEST IOWA...WITH THE SURFACE LOW ANYWHERE FROM
NORTHERN TO SOUTHWESTERN MISSOURI. GIVEN THE CONFIDENCE HPC HAS
HAD WITH THE ECMWF AND ECMWF ENSEMBLES WITH THIS SYSTEM...LEANED
TOWARDS IT AND KEPT MOST OF THE AREA DRY FRIDAY NIGHT. KEPT LOW
POPS IN THE FAR SOUTHWEST LATE FRIDAY NIGHT FOR CONTINUITY...BUT
MAY HAVE TO TAKE THESE OUT IN LATER FORECASTS IF SLOWER ECMWF
VERIFIES.
.LONG TERM...SATURDAY THROUGH TUESDAY...FORECAST CONFIDENCE LOW.
MAJOR DIFFERENCES EXIST DURING THIS PERIOD BETWEEN THE ECMWF AND
GFS. THE GFS CONTINUES TO BE MORE PROGRESSIVE WITH THE UPPER LOW
SATURDAY INTO SATURDAY NIGHT...TAKING IT ACROSS SOUTHERN IOWA AND
CENTRAL ILLINOIS. ASSOCIATED SURFACE LOW MOVES QUICKLY EAST FROM
CENTRAL MISSOURI TO KENTUCKY. THIS TRACK BRINGS PRECIPITATION INTO
THE AREA SATURDAY INTO SATURDAY EVENING.
THE ECMWF REMAINS SLOWER AND DEEPER WITH THE UPPER LOW DURING THIS
TIME...KEEPING IT ACROSS THE CENTRAL PLAINS. SURFACE LOW OCCLUDES
AS IT BECOMES VERTICALLY STACKED WITH THE UPPER LOW. THIS SCENARIO
ALSO BRINGS LIGHT PRECIPITATION INTO MAINLY SOUTHERN PORTIONS OF
THE AREA. WILL CONTINUE TO USE CONSENSUS POPS AND TEMPERATURES FOR
THIS PERIOD...THOUGH WOULD LEAN MORE TOWARD THE SLOWER LOOK OF THE
ECMWF.
ECMWF TAKES UPPER LOW AND DEVELOPS AN OPEN WAVE OUT OF IT SUNDAY
NIGHT THROUGH MONDAY AS IT MOVES EAST THROUGH THE REGION. IT DOES
BRING LIGHT PRECIPITATION ACROSS THE AREA WITH IT. THE GFS IS DRY
WITH HIGH PRESSURE ACROSS THE AREA DURING THIS TIME. THEY BOTH
GENERALLY SHOW SOME COLD AIR ADVECTION LATER MONDAY INTO
TUESDAY...WITH THE ECMWF SHOWING STRONG COLD AIR ADVECTION TUESDAY
WITH A SHARP UPPER TROUGH MOVING THROUGH THE REGION. THE GFS IS
MUCH WEAKER WITH THE COLD ADVECTION. WILL CONTINUE TO USE
CONSENSUS POPS AND TEMPERATURES DURING THIS TIME. MILD
TEMPERATURES SHOULD CONTINUE DESPITE THE MODEL DIFFERENCES.
&&
.AVIATION/12Z TAFS/...
MVFR CIGS HAVE ENGULFED ALL OF SRN WI EARLY THIS MRNG. WILL
CONTINUE MVFR CIGS INTO THE AFTN...WITH LIGHTER WINDS IN WRN CWA
POSSIBLY ALLOWING CIGS TO FALL INTO IFR CATEGORY FOR A TIME AT
KMSN. FOR NOW WL TREND TOWARD CLOUDS THINNING THIS AFTN...BUT
CONFIDENCE LOW DUE TO ABOVE DISCUSSION. LIGHTER BOUNDARY LAYER
WINDS AND LINGERING LOW LEVEL MOISTURE SHOULD ALLOW PATCHY FOG TO
DEVELOP TONIGHT.
&&
.MARINE...
NORTHWEST WINDS WILL CONTINUE TO DIMINISH THIS MORNING AS THE
PRESSURE GRADIENT FURTHER WEAKENS. LIGHT WIND CONDITIONS ARE THEN
EXPECTED FOR AN EXTENDED PERIOD OF TIME FROM TONIGHT THROUGH
FRIDAY...UNTIL LOW PRESSURE BEGINS TO STRENGTHEN OVER THE CENTRAL
PLAINS AND MEANDER EWD OVER THE WEEKEND.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
TODAY/TONIGHT AND AVIATION/MARINE...MBK
THURSDAY THROUGH TUESDAY...WOOD
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1143 PM CST TUE JAN 31 2012
.SHORT TERM...TONIGHT THROUGH FRIDAY
244 PM CST TUE JAN 31 2012
MAIN FORECAST CONCERNS ARE CLOUDS AND TEMPERATURES THROUGH FORECAST
PERIOD.
LATEST WATER VAPOR SATELLITE IMAGERY INDICATING WEAK SHORTWAVE
TROUGHS EMBEDDED IN WEST TO EAST ZONAL FLOW ACROSS THE CONTINENTAL
UNITED STATES. ONE SHORTWAVE TROUGH OVER THE UPPER MIDWEST IS
PRODUCING LOW STRATUS DECK OF CLOUDS ACROSS MUCH OF NORTHERN AND
CENTRAL MINNESOTA.
THE DETERMINISTIC 31.12Z NAM AND GFS INITIALIZED OVERALL UPPER LEVEL
PATTERN WELL PER LATEST UPPER AIR ANALYSIS. MAIN DIFFERENCE BETWEEN
THE DETERMINISTIC 31.12Z GFS AND NAM IS THE 31.12Z GFS SLIGHTLY
MORE ROBUST WITH WEAK SHORTWAVE TROUGH MOVING ACROSS THE UPPER GREAT
LAKES REGION WEDNESDAY NIGHT. OTHERWISE..THE DETERMINISTIC 31.12Z
GFS/NAM ARE IN DECENT AGREEMENT WITH SURFACE AND UPPER LEVEL FEATURES
THROUGH FORECAST PERIOD.
TONIGHT AND WEDNESDAY..LOW STRATUS DECK OF CLOUDS WILL CONTINUE TO
ADVANCE SOUTHEASTWARD INTO THE FORECAST AREA. BIG QUESTION WILL BE
HOW FAR SOUTH THE LOW STRATUS DECK ADVANCES. THE 31.12Z GFS AND
NAM DOES SHOW THE WESTERN EDGE OF STRATUS DECK TO ERODE AS THE LOW
CLOUDS ADVANCE INTO THE FORECAST AREA. FOR NOW HAVE INCREASED SKY
CONDITION ACROSS MUCH OF THE FORECAST AREA AFTER 00Z WEDNESDAY.
WITH REGION REMAINING UNDER CYCLONIC FLOW AND NEXT WEAK IMPULSE
TRACKS INTO THE UPPER GREAT LAKES REGION...LOW STRATUS DECK OF CLOUDS
IS EXPECTED TO REMAIN OVER THE NORTHEASTERN HALF OF THE FORECAST AREA
THROUGH WEDNESDAY NIGHT. THE 31.12Z GFS DOES INDICATE WEAK
LIFT/FORCING IN ASSOCIATION WITH THE WEAK IMPULSE AND PRODUCES SOME
LIGHT PRECIPITATION OVER NORTH CENTRAL WISCONSIN. AT THIS TIME...
WITH WEAK LIFT AND MINIMAL FORCING WILL CONTINUE WITH DRY
CONDITIONS ACROSS FORECAST AREA.
NEXT CONCERN IS BOTH THE 31.12Z GFS AND NAM CUTOFF UPPER LEVEL LOW
OVER THE SOUTHERN AND CENTRAL PLAINS AND LIFT UPPER LEVEL LOW INTO
CENTRAL KANSAS THURSDAY NIGHT INTO FRIDAY. BOTH THE 31.12Z GFS AND
NAM SHOW THE BEST ISENTROPIC LIFT AT 290K SURFACE TO BE SOUTH OF
FORECAST AREA. HAVE PUSHED PRECIPITATION CHANCES SOUTH AND
WEST OF FORECAST AREA THURSDAY NIGHT AND FRIDAY.
.LONG TERM...FRIDAY NIGHT TUESDAY
244 PM CST TUE JAN 31 2012
MAIN FORECAST CONCERNS ARE PRECIPITATION CHANCES FRIDAY NIGHT
INTO SUNDAY. THE DETERMINISTIC 31.12Z GFS/GEM/ECMWF ARE IN DECENT
AGREEMENT IN CUTTING OFF UPPER LEVEL LOW OVER THE SOUTHERN AND
CENTRAL PLAINS FRIDAY NIGHT AND SATURDAY. HOWEVER...THE DETERMINISTIC
MODELS ARE IN DISAGREEMENT IN LIFTING UPPER LEVEL LOW INTO THE UPPER
MIDWEST AND GREAT LAKES REGION AFTER 18Z SATURDAY. CONFIDENCE IN
PRECIPITATION CHANCES ARE LOW FRIDAY NIGHT INTO SATURDAY...DUE TO
HIGH VARIABILITY IN LIFTING/MOVING CUTOFF LOW INTO THE UPPER
MIDWEST. TEMPERATURES THROUGH FORECAST PERIOD WILL REMAIN ABOVE
NORMAL...AS UPPER LEVEL CUTOFF LOW ADVECTS WARMER AIR NORTHWARD INTO
THE UPPER MIDWEST.
&&
.AVIATION...THROUGH 06Z THURSDAY
1143 PM CST TUE JAN 31 2012
A LARGE STRATUS DECK WAS OVER THE TAF SITES LATE THIS EVENING.
IFR/LIFR CEILINGS WERE FOUND OVER MUCH OF MINNESOTA...WITH LOWER
MVFR CEILINGS AT KLSE. INFRARED SATELLITE IMAGERY WAS SHOWING BACK
EDGE OF THE STRATUS EXTENDING FROM KAQP TO KFRM WITH THE DISTANCE
SPEED TOOL INDICATING THIS BACK EDGE WAS MOVING EASTWARD AROUND 9
KNOTS. MODELS CONTINUE TO SHOW LIFR TO IFR CEILINGS AT KRST AND
LOWER MVFR CEILINGS AT KLSE THROUGH 14Z. FROM 14Z ON...MODELS
DIVERGE IN MOVING THE STRATUS OUT...WITH THE 02.00Z RUC KEEPING
MOISTURE TRAPPED UNDER THE INVERSION INTO THE AFTERNOON
HOURS...WHILE THE NAM SHOWS CLEARING THROUGH THE MORNING HOURS.
BASED ON LINEAR MOTION OF THE BACK EDGE...DID TRY AND TIME THE
STRATUS OUT OF THE TAF SITES...CLEARING KRST 13Z-14Z AND KLSE
AROUND 16Z-17Z. BUT CONFIDENCE NOT HIGH ON THIS SCENARIO. ONCE THE
STRATUS CLEARS...LOOK FOR JUST SCATTERED MID AND HIGH LEVEL CLOUDS
THROUGH 06Z THURSDAY. WITH THE MELTING SNOW...COULD SEE
VISIBILITIES DROP INTO THE 3-5SM RANGE BETWEEN 04Z-06Z THURSDAY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
244 PM CST TUE JAN 31 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...DTJ
LONG TERM....DTJ
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1051 PM CST TUE JAN 31 2012
UPDATED AVIATION PORTION FOR 06Z TAF ISSUANCE
.SHORT TERM...TONIGHT THROUGH WEDNESDAY.
LATEST RUC ANALYSIS AND SATELLITE/RADAR IMAGERY SHOW A MOISTURE
STARVED LOW PRESSURE SYSTEM MOVING OVER THE CENTRAL UPPER PENINSULA
EARLY THIS AFTERNOON...AND ITS ASSOCIATED COOL FRONT PUSHING ACROSS
CENTRAL WISCONSIN. THE COLDER AIR IS LAGGING BEHIND THE FRONT AND
CAN BE MARKED BY THE LEADING EDGE OF A LOW STRATUS DECK THAT IS
SHIFTING SE OVER MINNESOTA AND ALMOST TO THE WI BORDER. DESPITE THE
SHALLOW NATURE OF THE LOW MOISTURE ON 12Z RAOBS...MIXING HAS NOT
DETERRED ITS PROGRESS SO FAR TODAY. WILL MAKE SOME LAST MINUTE
ADJUSTMENTS TO SPEED UP ITS FORWARD MOTION IF THIS CONTINUES TO BE
THE CASE. AS THESE CLOUDS ADVANCE TOWARDS NORTHERN
WISCONSIN...CLOUDS AND TEMPS ARE THE MAIN FORECAST CONCERNS.
TONIGHT...LOW PRESSURE WILL CONTINUE TO TRACK TO THE EAST OVER THE
EASTERN UPPER PENINSULA INTO SOUTHEAST ONTARIO. MID AND HIGH CLOUDS
WILL DEPART THIS EVENING WITH THE ELONGATED SHORTWAVE TROUGH...BUT
PLENTY OF LOW CLOUDS UPSTREAM WILL SHIFT SE WITHIN A COOLER AIRMASS
WRAPPING AROUND THE LOW AND INTO THE NORTHERN HALF OF THE STATE.
ALTHOUGH THE MOISTURE IS SHALLOW AND SOME EROSION IS EXPECTED...THE
COOLER AIRMASS WILL PROMOTE ITS ADVANCEMENT ACROSS NORTH-CENTRAL AND
CENTRAL WISCONSIN TONIGHT. THINK DOWNSLOPING SHOULD PREVENT THE
STRATUS FROM MAKING IT INTO THE FOX VALLEY AND NORTHEAST
WISCONSIN...SO HAVE KEPT PARTLY CLOUDY WORDING THERE. NO REAL
CHANCE OF DECOUPLING TONIGHT...SO LOWS WILL BE MILD AND RANGE FROM
THE LOWER 20S NORTH TO AROUND 30 SOUTHEAST.
WEDNESDAY...STRATUS WILL LIKELY HANG AROUND FOR MUCH OF THE MORNING
OVER NORTHERN WISCONSIN THOUGH SOME EROSION IS LIKELY OVER CENTRAL
WISCONSIN WITH DAYTIME HEATING. THE COOLER AIRMASS WILL CONTINUE TO
MODERATE THROUGH THE AFTERNOON SO EXPECTING CLOUDS TO RETREAT TO THE
NORTH OR NORTHEAST THROUGH THE DAY. ALSO IN THE AFTERNOON...THE
NEXT SHORTWAVE TROUGH WILL MOVE INTO WESTERN WISCONSIN. MID-LEVELS
HAVE A DRY WEDGE SO NO REAL THREAT OF PRECIP. HIGHS WILL BE COOLER
THAN TODAY...AND WILL GO WITH MID TO UPPER 30S.
.LONG TERM...WEDNESDAY NIGHT THROUGH NEXT TUESDAY. SOUNDS LIKE A
BROKEN RECORD...BUT MORE MILD AND DRY WEATHER EXPECTED FOR THE
NEXT WEEK OR SO. THE SPLIT FLOW PATTER WILL CONTINUE WITH WEAK
SHORTWAVE TROUGHS MOVING BY TO THE NORTH THROUGH WITH LITTLE
MOISTURE WHILE MORE SIGNIFICANT SYSTEMS IN THE SOUTHERN STREAM STAY
TO OUR SOUTH. ANY PHASING THAT TAKES PLACE IS WELL TO OUR EAST.
THE BEST CHANCE OF ANY PRECIPITATION LOOKS TO BE SUNDAY OR SUNDAY
NIGHT AS SYSTEM IN THE SOUTHERN STREAM PASSES BY TO THE SOUTH. IT
MAY CLIP CENTRAL AND NORTHERN WISCONSIN WITH SOME LIGHT SNOW OR
RAIN BUT THAT/S ABOUT IT.
&&
.AVIATION...
LARGE AREA OF MVFR/IFR CIGS MOVING EAST THROUGH WI. MODELS SUGGEST
CLOUDS REMAINING OVER AREA THROUGH THE NIGHT...BREAKING UP BY MID
DAY WED. DOWNSLOPING...DUE TO WEST TO NORTHWEST WINDS EXPECTED TO
KEEP CIGS SCT TO BKN MVFR OVER FOX VALLEY AND NE WISCONSIN
(THROUGH OVERNIGHT HOURS). WEAK UPPER DISTURBANCE TO MOVE THROUGH
OVERNIGHT WED...WITH RETURN OF MAINLY MID AND HIGH CLOUDS...THOUGH
SOME MODELS INDICATE LOW CLOUDS TO RETURN TO NORTH-CENTRAL
LOCATIONS.
TE
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
557 PM MST THU FEB 2 2012
.UPDATE...
SNOW IS RAPIDLY DEVELOPING ACROSS SOUTHEAST WYOMING THIS EVENING.
SNOW WILL BECOME HEAVY AT TIMES...ESPECIALLY THIS EVENING. THESE
HIGH SNOW RATES WILL AFFECT MUCH OF INTERSTATE 80 AND 25 ACROSS
SOUTHEAST WYOMING. DESPITE IMPRESSIVE RADAR RETURNS OVER THE
NEBRASKA PANHANDLE...PRECIPITATION HAS YET TO REACH THE
GROUND. DEW POINT DEPRESSIONS STILL 20-25 DEGREES BELOW THE
STRONGEST RADAR RETURNS...BUT CEILINGS HAVE BEEN DROPPING SO SOME
SNOW SHOULD START HITTING THE GROUND NEAR THE WYOMING AND NEBRASKA
BORDER IN THE NEXT FEW HOURS. DRY NORTHEAST FLOW AT ALLIANCE AND
SCOTTSBLUFF MAY BE ENOUGH TO KEEP SNOW AT BAY UNTIL AFTER SUNRISE
FRIDAY...WHEN THE MAIN UPPER LOW EJECTS INTO THE PLAINS AND WRAP
AROUND SNOW LIFTS INTO THE AREA OUT OF COLORADO. ALL IN ALL
FORECAST ON TRACK WITH NO BIG CHANGES EXPECTED AT THIS TIME.
&&
.AVIATION...00Z TAF ISSUANCE...
SNOW WILL SPREAD ACROSS SOUTHEAST WYOMING THIS EVENING...
SIGNIFICANTLY REDUCING VISIBILITIES. THE HEAVIEST SNOW WILL BE
FOUND ALONG THE FOOTHILLS OF THE LARAMIE RANGE WHERE VISIBILITIES
WILL DROP BELOW 1/2 SM FROM MUCH OF TONIGHT. CYS WILL SEE THE
GREATEST IMPACT OF ALL TAF SITES TONIGHT. LAR WILL ALSO SEE
REDUCED VISIBILITIES BUT THE DURATION SHOULD BE SHORTER LIVED.
CDR AND AIA MOST LIKELY WILL BE EAST OF THE MAIN SNOW SHIELD
TONIGHT...WITH MVFR DEVELOPING.
&&
.PREV DISCUSSION... /ISSUED 325 PM MST THU FEB 2 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
HAZARDOUS WINTER STORM CONTINUES TO LOOK ON TRACK TO ARRIVE THIS
EVENING ACROSS SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. 500MB RUC ANALYSIS AT 20Z SHOWS THE MIDLEVEL TROUGH
CLOSING OFF TO THE EAST OF THE FOUR CORNERS REGION. UPPER LEVEL
DIVERGENCE TO THE NORTHEAST OF THE LOW IS CURRENTLY PRODUCING AN
AREA OF IR ENHANCEMENT STRETCHING FROM DENVER TO GOODLAND. THE
MODELS AGREE IN INCREASING LLVL N-NE UPSLOPE WINDS THRU THE EVENING
AND MOISTENING THE LOW/MID LEVELS. WHILE THE CURRENT DEWPOINT
DEPRESSIONS ARE HIGH TO THE EAST OF THE LARAMIE RANGE (15-20F)...LOW
LEVEL COLD-AIR ADVECTION AND TOP-DOWN MOISTENING WILL RESULT IN
SATURATION BY THIS EVENING. LOOKS LIKE THE PERIOD FROM 00Z-06Z IN
PARTICULAR IS FAVORABLE FOR HIGH SNOWFALL RATES ACROSS SOUTHEAST WY.
A BUFKIT TIME-HEIGHT PLOT FROM KCYS SHOWS THE COMBINATION OF
EASTERLY 700MB WINDS AND UPWARD MOTION IN THE DENDRITE GROWTH ZONE
BEING MAXIMIZED BETWEEN 00Z-06Z. SNOWFALL ACROSS THE NE PANHANDLE
WILL LIKELY HOLD OFF UNTIL LATE TONIGHT WHEN THE MIDLEVEL DYNAMICS
ARRIVE.
THE 500MB LOW WILL BEGIN ITS PROGRESSION TO THE NORTHEAST ON
FRIDAY MOVING...MOVING ACROSS EASTERN CO AND NORTHWESTERN KS. THE
HEAVIEST SNOWFALL ON FRIDAY...ESPECIALLY BY AFTN...IS EXPECTED OVER
THE SOUTHERN PART OF THE NEBRASKA PANHANDLE CLOSEST TO THE 700MB
LOW. 700MB FCTS AT 18Z FRI SHOW AN AXIS OF HIGHER NE WINDS (AROUND
35 KTS) STRETCHING ACROSS CHEYENNE COUNTY. BUFKIT SOUNDINGS AT KSNY
AT 18Z SUPPORT GUSTS TO 35 KTS...THUS WILL CONTINUE THE BLIZZARD
WARNING ACROSS CHEYENNE COUNTY. ANY SUBSTANTIAL MIDLEVEL
FRONTOGENESIS IS PROGGED TO BE SOUTH AND EAST OF THE CWA THROUGHOUT
THE ENTIRE EVENT. THUS...NOT EXPECTING OVERLY HIGH SNOWFALL
RATES...HOWEVER THE LONG DURATION OF LOW-LEVEL UPSLOPE WILL PRODUCE
STORM TOTAL SNOWFALL AMOUNTS BETWEEN 7 TO 10 INCHES ALONG INTERSTATE
80 THROUGH FRIDAY NIGHT. EXPECT HIGHER AMOUNTS IN THE
OROGRAPHICALLY FAVORED SOUTH LARAMIE RANGE NEAR THE I-80 SUMMIT.
AMOUNTS WILL DROP OFF TO THE NORTH AND WEST...IN AREAS FURTHER
REMOVED FROM THE MIDLEVEL LOW. SNOW WILL BEGIN TO TAPER OFF FROM
WEST TO EAST OVER THE CWA BY LATE FRIDAY NIGHT AS THE MAIN 500MB LOW
CONTINUES ITS PROGRESSION EASTWARD AND THE SFC HIGH SETTLES OVER
SOUTHEAST WY.
LONG TERM...SATURDAY THROUGH THURSDAY
12Z GFS AND ECMWF 500 MB SYNOPTIC PATTERNS SIMILAR...LEADING TO
MODERATE TO HIGH CONFIDENCE IN THEIR RESPECTIVE MODEL SOLUTIONS.
SATURDAY...SHORTWAVE TROUGH ALOFT WILL BE MOVING OFF TO OUR
EAST...THUS DECREASING SNOW CHANCES ACROSS OUR SOUTHERN COUNTIES.
SUNDAY...SLOW WARMING TREND ON TAP AS HEIGHTS AND THICKNESSES RISE.
DRY WITH LACK OF LOW AND MID LEVEL MOISTURE.
MONDAY...ANOTHER WEAK COLD FRONT MOVES SOUTH ACROSS OUR
COUNTIES...THOUGH THE BULK OF THE COLDER AIR WILL REMAIN NORTH AND
EAST OF OUR AREA. CONTINUED DRY WITH LIMITED LOW AND MID LEVEL
MOISTURE.
TUESDAY-THURSDAY...DRY NORTHWEST FLOW ALOFT WILL PREVAIL. WARMING
TREND WILL CONTINUE AS HEIGHTS AND THICKNESSES RISE.
AVIATION...18Z TAFS
THROUGH 00Z...CIGS AND VISIBILITIES LOWERING
TO IFR IN SNOW AND FOG ACROSS CARBON COUNTY WITH MOUNTAIN
OBSCURATION. VFR ELSEWHERE.
AFTER 00Z...WIDESPREAD IFR AND LIFR DEVELOPING IN SNOW AND FOG
AT RAWLINS...LARAMIE...CHEYENNE AND SIDNEY ALONG WITH MOUNTAIN
OBSCURATION. MVFR DUE TO CLOUDS...SNOW AND FOG DEVELOPING AT
CHADRON...SCOTTSBLUFF AND ALLIANCE.
AFTER 12Z...WIDESPREAD IFR IN SNOW AND FOG...WITH LIFR AND VLIFR AT
TIMES AT LARAMIE...CHEYENNE AND SIDNEY. MOUNTAINS OBSCURED. RUBIN
FIRE WEATHER...NO FIRE WEATHER CONCERNS
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 11 PM FRIDAY FOR WYZ106-WYZ107-WYZ116-
WYZ117-WYZ118-WYZ119.
WINTER WEATHER ADVISORY UNTIL 5 PM FRIDAY FOR WYZ103-WYZ114-
WYZ115.
WINTER WEATHER ADVISORY FROM 11 PM THURSDAY TO 11 PM FRIDAY FOR
WYZ108.
NE...WINTER WEATHER ADVISORY FROM 11 PM THURSDAY TO 11 PM FRIDAY FOR
NEZ003-NEZ019-NEZ096.
WINTER STORM WARNING FROM 11 PM THURSDAY TO 11 PM FRIDAY FOR
NEZ020-NEZ021-NEZ054.
BLIZZARD WARNING FROM 11 PM THURSDAY TO 11 PM FRIDAY FOR NEZ055.
&&
$$
UPDATE...LIEBL
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM...RUBIN
AVIATION...LIEBL
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
323 AM EST FRI FEB 3 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE OVER NORTHERN INDIANA AND THE SOUTHERN GREAT LAKES
WILL CONTINUE MOVING EAST. MEANWHILE AN UPPER TROUGH OVER THE
CENTRAL ROCKIES WILL DEVELOP INTO A CLOSED UPPER LOW AND MOVE OUR
WAY SATURDAY AND SATURDAY NIGHT. A SURFACE LOW PRESSURE SYSTEM WILL
TRACK ACROSS KENTUCKY AND TENNESSEE SATURDAY AND SATURDAY NIGHT.
HIGH PRESSURE BEHIND THIS SYSTEM WILL BUILD OUR WAY LATE SUNDAY AND
MONDAY. IN THE EXTENDED HIGH PRESSURE WILL DOMINATE OUR WEATHER.
HOWEVER A WEAK AND DRY COLD FRONT WILL MOVE ACROSS OUR REGION AROUND
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
WILL BUMP WORDING UP FOR FOG POTENTIAL TO AREAS OF FOG/PATCHY DENSE
OVERNIGHT...AS LAPS SOUNDINGS AND OBS LOOK VERY SIMILAR TO LAST
NIGHT. SREF PROBABILITIES DO NOT INDICATE FOG...BUT THESE PROGS HAVE
LEFT SOMETHING TO BE DESIRED TO SAY THE LEAST LATELY.
RUC SOUNDINGS SHOW A DEPTH OF MOISTURE NOT QUITE AS DEEP AS LAST
NIGHT...BUT STILL SUBSTANTIAL. ADDED CIRRUS MAY VERY WELL PREVENT
WIDESPREAD NEAR ZERO VISIBILITIES LIKE EXPERIENCED THIS
MORNING...BUT SHOULD STILL ALLOW WIDESPREAD VISIBILITIES BELOW 1
MILE. WILL UPDATE HWO AND ISSUE SPS TO HIGHLIGHT.
OTHERWISE...FEW CHANGES NECESSARY TO GOING FORECAST. DID TWEAK
TEMPERATURES SLIGHTLY BASED ON HOURLY NUMERICAL GUIDANCE AND
OBS/DEWPOINT TRENDS...AND BROUGHT WINDS MORE TOWARDS CALM TO VERY
LIGHT PER LATEST OBS.
PREVIOUS DISCUSSION FOLLOWS.
AREAS OF FOG AND STRATUS EARLIER OVER THE WESTERN PART OF OUR REGION
HAS TAKEN MOST OF THE DAY TO CLEAR OUT. HIGH PRESSURE WILL BRING
LIGHT WINDS AND MOSTLY CLEAR SKIES EARLY ON AND THERE IS SOME
POTENTIAL FOG SOME FOG AGAIN TONIGHT. ON THE OTHER HAND...THERE
WILL BE MORE CIRRUS MOVING IN OVERNIGHT WHICH WOULD LESSEN THE
POTENTIAL FOR FOG. THE 15Z VSREF SHOWS PRACTICALLY NO POTENTIAL FOR
FOG...WHILE THE RUC SOUNDINGS INDICATE A MUCH GREATER POTENTIAL FOG
FOG. THE WINDS AND CLOUDS LATER TONIGHT WILL LESSEN THE POTENTIAL
QUITE A BIT. BUT WITH SOME UNCERTAINTY WILL MENTION PATCHY FOG MOST
AREAS LATE TONIGHT. I DON`T THINK THERE WILL BE WIDESPREAD DENSE
FOG AS THERE WAS LAST NIGHT.
WITH CLEAR SKIES AND LIGHT WINDS WILL UNDERCUT MOS TEMPERATURES A
LITTLE TONIGHT. MOST AREAS LAST NIGHT ENDED SEVERAL DEGREES COOLER.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
THE HIGHEST DEWPOINTS AND LIGHTEST WINDS WILL BE ACROSS OUR NORTH
AND NORTHEAST SECTIONS FRIDAY MORNING. WILL MENTION SOME PATCHY FOG
ALL BUT FAR SOUTHWEST EARLY FRIDAY. OTHERWISE...FRIDAY WILL BE
ANOTHER VERY NICE DAY WITH INCREASING HIGH CLOUDS. WENT CLOSE TO A
MET/MAV BLEND ON TEMPERATURES.
ALL MODELS SPREAD RAIN INTO OUR REGION FRIDAY NIGHT AND SATURDAY
APPEARS TO BE A VERY WET DAY WITH PERIODS OF RAIN MOST AREAS. BUT
WITH SLIGHTLY LESSER CHANCES ACROSS OUR FAR NORTH. AS FAR AS
TEMPERATURES WENT SLIGHTLY ABOVE MAV/MET BLEND FRIDAY NIGHT AND
SLIGHTLY BELOW SATURDAY AS CLOUDS AND PRECIP SHOULD LIMIT ANY
DIURNAL TREND ON TEMPERATURES.
1000 TO 850 MB THICKNESS DROP TO NEAR OR SLIGHTLY BELOW 1300 METERS
LATE SATURDAY NIGHT ACROSS OUR NORTH AND WILL MENTION CHANCE OF
MIXED PRECIP THERE. BUT IT IS POSSIBLE THE PRECIP MAY BE OVER
ACROSS OUR NORTH BY THAT TIME.
MODELS START TO MOVE THE UPPER LOW TO THE SOUTHEAST AS AN UPPER
RIDGE DEVELOPS OVER THE NORTHERN PLAINS. JUST ABOUT ALL MODELS NOW
LEAN TOWARDS A DRY DAY SUNDAY. BUT WITH AN UPPER TROUGH STILL OVER
OUR REGION 12Z-18Z SUNDAY...I AM STILL A BIT RELUCTANT TO JUMP ON
THE DRY BAND WAGON YET SUNDAY WITH THE POSSIBLE EXCEPTION OF OUR
NORTHERN AREAS WOULD DRY OUT FIRST. EITHER CASE...ANY REMAINING
PRECIP WILL END DURING THE DAY SUNDAY AS THE UPPER TROUGH MOVES TO
THE SOUTHEAST. DID NOT MAKE ANY SIGNIFICANT CHANGES TO TEMPERATURES
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
QUIET PATTERN FOR THE LONG TERM. MODELS ARE MOVING THE TROUGH AXIS
THROUGH A LITTLE BIT FASTER SUNDAY SO BY SUNDAY NIGHT IT LOOKS LIKE
ALL PRECIP SHOULD HAVE MOVED OUT OF THE AREA. WITH THE VESTIGES OF
AN UPPER LOW STILL HANGING AROUND UPSTREAM AND MOVING ACROSS ON
MONDAY COULD SEE A LITTLE INCREASED CLOUD COVER BUT THAT/S IT GIVEN
THE LACK OF MOISTURE AND LACK OF FORCING. AFTER THAT MOVES THROUGH
MONDAY UPPER FLOW INCLUDES A DEEP UPPER LOW MOVING INTO ST JAMES BAY
AND ANOTHER UPPER LOW DIGGING INTO WESTERN MEXICO BUT VERY LITTLE
GOING ON ELSEWHERE. TEMPERATURES LOOK A LITTLE WARMER THAN AVERAGE
FOR THIS TIME OF YEAR BUT ALLBLEND CAPTURED THIS WELL. ONLY CHANGES
TO ALLBLEND FOR POPS WAS TO REMOVE SLIGHT CHANCE IN THE SOUTH ON
SUNDAY NIGHT DUE TO FASTER MOVEMENT OF THE TROUGH AND REMOVAL OF
SLIGHT CHANCE POPS IN DAY 7 WITH ENSEMBLES AND OPERATIONAL GFS
FAVORING DRY.
&&
.AVIATION /DISCUSSION FOR THE 030900Z KIND TAF UPDATE/...
VISIBILITIES HAVE BEEN SLOW TO FALL IN THE VICINITY OF KIND WITH
ONLY SOME PATCHY IFR RESTRICTIONS SHOWING UP SO FAR. DELAY PROBABLY
AT LEAST PARTLY DUE TO THE INCREASING HIGH CLOUD COVER AND A LIGHT
SURFACE WIND OFF THE CITY. DOESN/T APPEAR THERE IS ANY IMMEDIATE
THREAT OF LOW CONDITIONS AROUND KIND...SO WILL BACK OFF THE IFR
VISIBILITY RESTRICTIONS TO A FEW HOURS EITHER SIDE OF
SUNRISE...ROUGHLY 031100Z-031500Z. PREVIOUS DISCUSSION FOLLOWS.
WIDESPREAD IFR AND LOCAL VLIFR VISIBILITIES IN FOG UNTIL AFTER
SUNRISE. AFTER THAT RAPID IMPROVEMENT TO P6SM. DETAILS ON TIMING
WILL LIKELY BE ADJUSTED IN LATER FORECASTS.
FOR MOST PART NO CEILINGS OR CEILINGS ABOVE 10 THOUSAND FEET.
CEILINGS AROUND 5 THOUSAND FEET AFT 09Z SATURDAY AT KIND.
WINDS CONTINUING TOO LIGHT TO IMPACT OPERATIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/NIELD
SHORT TERM...JH
LONG TERM....CP
AVIATION...JK/JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1133 PM EST THU FEB 2 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE OVER NORTHERN INDIANA AND THE SOUTHERN GREAT LAKES
WILL CONTINUE MOVING EAST. MEANWHILE AN UPPER TROUGH OVER THE
CENTRAL ROCKIES WILL DEVELOP INTO A CLOSED UPPER LOW AND MOVE OUR
WAY SATURDAY AND SATURDAY NIGHT. A SURFACE LOW PRESSURE SYSTEM WILL
TRACK ACROSS KENTUCKY AND TENNESSEE SATURDAY AND SATURDAY NIGHT.
HIGH PRESSURE BEHIND THIS SYSTEM WILL BUILD OUR WAY LATE SUNDAY AND
MONDAY. IN THE EXTENDED HIGH PRESSURE WILL DOMINATE OUR WEATHER.
HOWEVER A WEAK AND DRY COLD FRONT WILL MOVE ACROSS OUR REGION AROUND
THE MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
WILL BUMP WORDING UP FOR FOG POTENTIAL TO AREAS OF FOG/PATCHY DENSE
OVERNIGHT...AS LAPS SOUNDINGS AND OBS LOOK VERY SIMILAR TO LAST
NIGHT. SREF PROBABILITIES DO NOT INDICATE FOG...BUT THESE PROGS HAVE
LEFT SOMETHING TO BE DESIRED TO SAY THE LEAST LATELY.
RUC SOUNDINGS SHOW A DEPTH OF MOISTURE NOT QUITE AS DEEP AS LAST
NIGHT...BUT STILL SUBSTANTIAL. ADDED CIRRUS MAY VERY WELL PREVENT
WIDESPREAD NEAR ZERO VISIBILITIES LIKE EXPERIENCED THIS
MORNING...BUT SHOULD STILL ALLOW WIDESPREAD VISIBILITIES BELOW 1
MILE. WILL UPDATE HWO AND ISSUE SPS TO HIGHLIGHT.
OTHERWISE...FEW CHANGES NECESSARY TO GOING FORECAST. DID TWEAK
TEMPERATURES SLIGHTLY BASED ON HOURLY NUMERICAL GUIDANCE AND
OBS/DEWPOINT TRENDS...AND BROUGHT WINDS MORE TOWARDS CALM TO VERY
LIGHT PER LATEST OBS.
PREVIOUS DISCUSSION FOLLOWS.
AREAS OF FOG AND STRATUS EARLIER OVER THE WESTERN PART OF OUR REGION
HAS TAKEN MOST OF THE DAY TO CLEAR OUT. HIGH PRESSURE WILL BRING
LIGHT WINDS AND MOSTLY CLEAR SKIES EARLY ON AND THERE IS SOME
POTENTIAL FOG SOME FOG AGAIN TONIGHT. ON THE OTHER HAND...THERE
WILL BE MORE CIRRUS MOVING IN OVERNIGHT WHICH WOULD LESSEN THE
POTENTIAL FOR FOG. THE 15Z VSREF SHOWS PRACTICALLY NO POTENTIAL FOR
FOG...WHILE THE RUC SOUNDINGS INDICATE A MUCH GREATER POTENTIAL FOG
FOG. THE WINDS AND CLOUDS LATER TONIGHT WILL LESSEN THE POTENTIAL
QUITE A BIT. BUT WITH SOME UNCERTAINTY WILL MENTION PATCHY FOG MOST
AREAS LATE TONIGHT. I DON`T THINK THERE WILL BE WIDESPREAD DENSE
FOG AS THERE WAS LAST NIGHT.
WITH CLEAR SKIES AND LIGHT WINDS WILL UNDERCUT MOS TEMPERATURES A
LITTLE TONIGHT. MOST AREAS LAST NIGHT ENDED SEVERAL DEGREES COOLER.
&&
.SHORT TERM /FRIDAY THROUGH SUNDAY/...
THE HIGHEST DEWPOINTS AND LIGHTEST WINDS WILL BE ACROSS OUR NORTH
AND NORTHEAST SECTIONS FRIDAY MORNING. WILL MENTION SOME PATCHY FOG
ALL BUT FAR SOUTHWEST EARLY FRIDAY. OTHERWISE...FRIDAY WILL BE
ANOTHER VERY NICE DAY WITH INCREASING HIGH CLOUDS. WENT CLOSE TO A
MET/MAV BLEND ON TEMPERATURES.
ALL MODELS SPREAD RAIN INTO OUR REGION FRIDAY NIGHT AND SATURDAY
APPEARS TO BE A VERY WET DAY WITH PERIODS OF RAIN MOST AREAS. BUT
WITH SLIGHTLY LESSER CHANCES ACROSS OUR FAR NORTH. AS FAR AS
TEMPERATURES WENT SLIGHTLY ABOVE MAV/MET BLEND FRIDAY NIGHT AND
SLIGHTLY BELOW SATURDAY AS CLOUDS AND PRECIP SHOULD LIMIT ANY
DIURNAL TREND ON TEMPERATURES.
1000 TO 850 MB THICKNESS DROP TO NEAR OR SLIGHTLY BELOW 1300 METERS
LATE SATURDAY NIGHT ACROSS OUR NORTH AND WILL MENTION CHANCE OF
MIXED PRECIP THERE. BUT IT IS POSSIBLE THE PRECIP MAY BE OVER
ACROSS OUR NORTH BY THAT TIME.
MODELS START TO MOVE THE UPPER LOW TO THE SOUTHEAST AS AN UPPER
RIDGE DEVELOPS OVER THE NORTHERN PLAINS. JUST ABOUT ALL MODELS NOW
LEAN TOWARDS A DRY DAY SUNDAY. BUT WITH AN UPPER TROUGH STILL OVER
OUR REGION 12Z-18Z SUNDAY...I AM STILL A BIT RELUCTANT TO JUMP ON
THE DRY BAND WAGON YET SUNDAY WITH THE POSSIBLE EXCEPTION OF OUR
NORTHERN AREAS WOULD DRY OUT FIRST. EITHER CASE...ANY REMAINING
PRECIP WILL END DURING THE DAY SUNDAY AS THE UPPER TROUGH MOVES TO
THE SOUTHEAST. DID NOT MAKE ANY SIGNIFICANT CHANGES TO TEMPERATURES
SUNDAY.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
QUIET PATTERN FOR THE LONG TERM. MODELS ARE MOVING THE TROUGH AXIS
THROUGH A LITTLE BIT FASTER SUNDAY SO BY SUNDAY NIGHT IT LOOKS LIKE
ALL PRECIP SHOULD HAVE MOVED OUT OF THE AREA. WITH THE VESTIGES OF
AN UPPER LOW STILL HANGING AROUND UPSTREAM AND MOVING ACROSS ON
MONDAY COULD SEE A LITTLE INCREASED CLOUD COVER BUT THAT/S IT GIVEN
THE LACK OF MOISTURE AND LACK OF FORCING. AFTER THAT MOVES THROUGH
MONDAY UPPER FLOW INCLUDES A DEEP UPPER LOW MOVING INTO ST JAMES BAY
AND ANOTHER UPPER LOW DIGGING INTO WESTERN MEXICO BUT VERY LITTLE
GOING ON ELSEWHERE. TEMPERATURES LOOK A LITTLE WARMER THAN AVERAGE
FOR THIS TIME OF YEAR BUT ALLBLEND CAPTURED THIS WELL. ONLY CHANGES
TO ALLBLEND FOR POPS WAS TO REMOVE SLIGHT CHANCE IN THE SOUTH ON
SUNDAY NIGHT DUE TO FASTER MOVEMENT OF THE TROUGH AND REMOVAL OF
SLIGHT CHANCE POPS IN DAY 7 WITH ENSEMBLES AND OPERATIONAL GFS
FAVORING DRY.
&&
.AVIATION /DISCUSSION FOR 030600Z TAFS/...
WIDESPREAD IFR AND LOCAL VLIFR VISIBILITIES IN FOG UNTIL AFTER
SUNRISE. AFTER THAT RAPID IMPROVEMENT TO P6SM. DETAILS ON TIMING
WILL LIKELY BE ADJUSTED IN LATER FORECASTS.
FOR MOST PART NO CEILINGS OR CEILINGS ABOVE 10 THOUSAND FEET.
CEILINGS AROUND 5 THOUSAND FEET AFT 09Z SATURDAY AT KIND.
WINDS CONTINUING TOO LIGHT TO IMPACT OPERATIONS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JH
NEAR TERM...JH/NIELD
SHORT TERM...JH
LONG TERM....CP
AVIATION...JK
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1140 PM CST THU FEB 2 2012
...UPDATED FOR 06Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
COMPLICATED FORECAST TONIGHT ALBEIT A DRY ONE. FOG WAS SLOW TO BURN
OFF TODAY ACROSS THE NORTHEAST AND MOISTURE REMAINS JUST TO OUR
EAST. LOW LEVEL FLOW TONIGHT WILL BECOME EASTERLY AND ADVECT THE
MOISTURE/FOG BACK INTO THE AREA. I AM EXPECTING SIMILAR AREAS TO
HAVE DENSE FOG TONIGHT INTO FRIDAY MORNING AS WE DID LAST NIGHT.
THE QUESTION IS ONE OF TIMING AND EXTENT OF THE DENSE FOG. HRRR HAD
A DECENT HANDLE ON THE REDUCED VISIBILITIES BUT LIKE THIS MORNING...
IT WAS A BIT OVERDONE ON EXTENT. I USED TIMING SIMILAR TO THE HRRR
BUT EXTENT SIMILAR TO LAST NIGHT. TIME/HEIGHT CROSS SECTIONS
INDICATE DRY AIR JUST OFF THE SURFACE SO MOISTURE WON`T GET DEEP
ENOUGH TO PRODUCE PRECIP. WE ALSO DON`T HAVE ANY LIFT TO SPEAK OF
UNTIL FRIDAY MORNING. TONIGHTS LOW TEMPS WERE KEPT SIMILAR TO LAST
NIGHT.
.LONG TERM /FRIDAY THROUGH FRIDAY/...
COMPLICATED WEATHER SITUATION WITH THE LOW COMING OUT OF THE
ROCKIES. IN THE LONG WAVE PATTERN THE MEAN RIDGE POSITION IS IN THE
110W TO 115W AREA WITH THE MEAN TROUGH TO THE EAST IN THE 70W AREA.
LOW COMING OUT OF THE ROCKIES LIFTS NORTHEAST THEN TAKES A TURN TO
THE EAST AND EVENTUALLY EAST-SOUTHEAST AS IT MOVES PAST THE MEAN
RIDGE POSITION. THIS LENDS CREDIBILITY TO THE SOUTHWARD SHIFT IN
THE MODELS AND ALSO THE RAPID WEAKENING AS THE SYSTEM MOVES EAST.
THE SNOWFALL MAY WELL LOOK SOMEWHAT SIMILAR TO THE STORM SYSTEM A
FEW WEEKS BACK THAT DROPPED THE HEAVY SNOWFALL IN KS. A COUPLE
ANALOG CASES STAND OUT TODAY WITH ONE BEING THE EVENT AROUND 21 JAN
1990...THOUGH SHIFTED A WAYS FARTHER SOUTH...THE OTHER THE EVENT
AROUND 22 MAR 2006. IN BOTH CASES THE SYSTEM WEAKENED AS IT MOVED
EAST WITH MUCH OF THE HEAVY SNOW REMAINING WEST OF THE MO RIVER.
SEE A SIMILAR SITUATION HERE. INITIALLY DRY LOW LEVEL AIR WILL
INHIBIT PRECIP DEVELOPMENT. THE UPPER LOW AND STRONG DYNAMICS WILL
OVERCOME THAT WITH THE COLUMN SATURATING OVER THE CENTRAL AND SOUTH
BY FRI EVENING. PRECIPITATION WILL INITIALLY FALL AS RAIN WITH A
VERY GRADUAL CHANGE TO SNOW AS COLD AIR DEVELOPS AROUND THE CLOSED
LOW. SOME SLEET IS ALSO POSSIBLE ALONG THE NORTH EDGE OF THE PRECIP
AREA EARLY ON DUE TO A DECENT WARM LAYER...BUT EVAPORATIONAL COOLING
MAKING UP THE DIFFERENCE RESULTING IN RE-FREEZE. LOW WILL PULL TO
THE EAST SAT NIGHT WITH LAST OF THE SNOW ENDING ON SUN. BACKED OFF
A BIT ON THE WINTER STORM WATCH DUE TO UNANIMOUS SHIFT IN THE
MODELS. THINKING AT THIS POINT IS IF WINTER WINTER STORM CONDITIONS
ARE TO BE MET...IT WILL BE A MARGINAL CASE AND CURRENT ADJUSTMENTS
TO THE WATCH AREA INCLUDE ABOUT A COUNTY BUFFER TO AREA LIKELY TO
REACH CRITERIA. WINDS ARE NOT LIKELY TO BE A MAJOR FACTOR WITH THIS
SYSTEM...THOUGH MAY GUST TO 25 TO 30 MPH AT TIMES. BLOWING SNOW
WILL BE LIMITED BY THE SPRING TYPE NATURE OF THE SYSTEM. NO
SIGNIFICANT COOLING BEHIND THE STORM SYSTEM AS THE AIRMASS IS
PACIFIC IN NATURE. ARCTIC AIR IS EXPECTED TO REMAIN WELL TO THE
NORTHEAST OF IA. DRY WEATHER AS WE HEAD INTO NEXT WEEK WITH TEMPS
REMAINING ABOVE NORMAL BY A FEW DEGREES.
&&
.AVIATION...03/06Z
LOW STATUS AND DENSE FOG WILL CONTINUE TO PLAGUE LOCATIONS NEAR KMCW
AND KALO OVERNIGHT INTO FRIDAY MORNING BEFORE GRADUALLY DISSIPATING.
THIS WILL PRODUCE LIFR CONDITIONS IN THESE AREAS THROUGH THE MORNING
HOURS BEFORE VISIBILITIES IMPROVE. ELSEWHERE...WIDESPREAD VFR
CEILINGS WILL PASS OVER THE STATE AHEAD OF AN APPROACHING STORMS.
LIGHT RAIN IS EXPECTED TO DEVELOP ACROSS PORTIONS OF WESTERN AND
SOUTHERN IA ON FRIDAY MORNING WITH CEILINGS LOWERING DURING THE
DAY. ANTICIPATE MVFR TO IFR CONDITIONS TO OVERSPREAD SOUTHERN AND
CENTRAL IOWA ON FRIDAY NIGHT AS PRECIPITATION INTENSIFIES WITH A
GRADUAL TRANSITION TO SNOW IN WESTERN IOWA OVERNIGHT. EASTERLY
WINDS WILL CONTINUE THROUGH FRIDAY AND INCREASE WITH SOME GUSTINESS
DEVELOPING AS THE LOW PRESSURE APPROACHES.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM FRIDAY EVENING THROUGH LATE SATURDAY
NIGHT FOR ADAIR-ADAMS-AUDUBON-CARROLL-CASS-CRAWFORD-DALLAS-
GREENE-GUTHRIE-MADISON-TAYLOR-UNION.
DENSE FOG ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM CST FRIDAY FOR
DAVIS-JASPER-MAHASKA-MARION-MARSHALL-MONROE-POWESHIEK-TAMA-
WAPELLO.
DENSE FOG ADVISORY FROM 9 PM THIS EVENING TO 10 AM CST FRIDAY
FOR BLACK HAWK-BREMER-BUTLER-CERRO GORDO-FRANKLIN-GRUNDY-HANCOCK-
HARDIN-WINNEBAGO-WORTH.
&&
$$
SHORT TERM...FAB
LONG TERM...MS FEB 12
AVIATION...COGIL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
408 AM EST FRI FEB 3 2012
.SYNOPSIS/NEAR TERM...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF
DOMINATING THE UPR LKS AROUND VORTEX OVER NRN QUEBEC. DESPITE THIS
NW FLOW...WHICH USUALLY BRINGS SOME INTENSE CHILL TO UPR MI THIS
TIME OF YEAR...THE AIRMASS IS UNSEASONABLY WARM OVER THE AREA. 00Z
H85 TEMPS RANGE FROM 1C AT MPX AND -1C AT GRB TO -5C AT INL AND APX
TO -8C AT YPL. ALTHOUGH THE AIR TO THE N AND NE TOWARD THE VORTEX IS
COLDER...THE 00Z H85 TEMPS AT CHURCHILL MANITOBA AND MOOSONEE ON THE
S SHORE OF JAMES BAY ARE ONLY -14C AND -11C RESPECTIVELY. 00Z RAOBS
INDICATE THESE HI H85 TEMPS ARE ASSOCIATED WITH A SHARP SUBSIDENCE
INVRN...WITH LLVL MSTR TRAPPED BLO THE INVRN BASE RESULTING IN
WDSPRD LO CLD FM THE UPR MIDWEST THRU THE UPR GRT LKS AND INTO
ONTARIO. A FEW BREAKS IN THE ST/SC ARE OVER NW LK SUP. THERE IS A
DISTURBANCE EMBEDDED IN THE NW FLOW ALF PASSING THRU NRN ONTARIO.
ALTHOUGH THIS SHRTWV IS PASSING WELL NE OF THE AREA...SOME RADAR
ECHOES UP TO 15 DBZ HAVE SHOWN UP TO THE NE OVER OVER LK SUP ALONG
ATTENDANT LO PRES TROF AXIS EXTENDING SWWD FM SFC LO NEAR MOOSONEE
INTO ERN LK SUP. SFC HI PRES UNDER 12HR H3 HGT RISES UP TO 110M AT
GRB STRETCHES ESEWD FM NRN MN THRU NE WI INTO LWR MI. THERE IS MORE
CLEARING OVER FAR NW ONTARIO...WHERE DRIER LLVL AIR IS PRESENT.
IN THE NEAR TERM...ALTHOUGH SOME BREAKS IN THE LO CLD MAY IMPACT NW
UPR MI...OVC ST/SC WL BE RULE THRU SUNRISE OVER MOST OF THE AREA.
SINCE THE AIRMASS IS SO WARM...ANY PCPN OVER THE ERN CWA WL BE
NOTHING MORE THAN DZ OR PERHAPS FZDZ INLAND FM THE SHORE/FLURRIES.
THE CLDS WL GREATLY LIMIT THE FALL OF THE THERMOMETER...WITH
READINGS GENERALLY NOT FAR FM 32 AT SUNRISE TO PERHAPS UPR 20S OVER
THE INTERIOR.
&&
.SHORT TERM /TODAY THRU SAT NGT/...
TODAY...HI PRES RDG AXIS TRAILING DISTURBANCE/SFC LO NOW IN NE
ONTARIO WL BRING A DRY DAY TO UPR MI. MAIN FCST CONCERN WL BE IF AND
WHEN LO CLDS OVER THE CWA WL BREAK UP AND THE IMPACT ON TEMPS. BOTH
THE 00Z NAM/LOCAL WRF-ARW RUNS SHOW DRIER H95-9 AIR NOW OVER FAR NW
ONTARIO PUSHING INTO THE CWA...BUT NOT UNTIL LATE IN THE DAY. IN
CONCERT WITH MORE ACYC FLOW...EXPECT THE LO CLDS TO BREAK UP. BUT
THIS SHOULD BE TOO LATE IN THE DAY...ONLY AFT 21Z OR SO...TO HAVE A
SNGFT IMPACT ON TEMPS. WITH TEMPS SO WARM...THE CLD TRENDS MAY BE
SIMILAR TO WHAT HAPPENS HERE IN EARLY SPRING...WITH CLRG OVER LK SUP
FASTER THAN THE LAND. PER UPSTREAM HI TEMPS YDAY AND PERSISTENT CLD
COVER OVER LAND...EXPECT TEMPS TO TOP OUT ON THE LO SIDE OF GUIDANCE
AND IN THE LO TO MID 30S.
TNGT...SFC HI PRES/DRY AIRMASS WL BE DOMINATING. WITH THE RDG AXIS
DIRECTLY OVHD...WINDS WL BE LGT IN THE EVNG. BUT AS ANOTHER
DISTURBANCE DROPS SEWD THRU ONTARIO IN THE NW FLOW ALF...THE W WIND
MAY PICK UP AGAIN...ESPECIALLY NEAR LK SUP. EXPECT THE LOWEST MIN
TEMPS TOWARD THE LO END OF GUIDANCE NEAR THE WI BORDER WITH LIGHTER
WINDS THE WHOLE NGT. ALTHOUGH THE MERCURY MAY DIP INTO THE SINGLE
DIGITS ABV ZERO AT A FEW PLACES...THESE READINGS WL STILL BE WELL
ABV AVG.
SAT...NEXT SHRTWV DROPPING SSEWD IN NW FLOW ALF ARND VORTEX IN
QUEBEC WL BE DIGGING INTO THE UPR LKS. THE 00Z CNDN MODEL IS FARTHER
W WITH THE TRACK OF THIS FEATURE...WHILE THE 00Z NAM/GFS ARE A BIT
FARTHER TO THE E. PER NCEP GUIDANCE...FOLLOWED THE INTERMEDIATE
TRACK OF THE 12Z ECWMF. ALTHOUGH THE AIRMASS WL BE RATHER DRY...
OPTED TO INCLUDE SCHC POPS FOR SHSN OVER THE E ON THE CYC SIDE OF
THE TRACK OF THIS FEATURE...WHERE THE GFS/ECMWF GENERATE SOME LGT
PCPN UNDER SHARPER DPVA/DEEP LYR QVECTOR CNVGC.
SAT NGT...ONCE THE SHRTWV PASSES SAT EVNG...EXPECT SFC HI PRES RDG
TO BUILD BACK INTO THE UPR LKS UNDER RISING HGTS/DNVA/DEEP LYR
QVECTOR DVGC. FCST H85 TEMPS IN THE -4 TO -8C RANGE IN THE WAKE OF
THE SHRTWV WL BE TOO HI FOR LES. WITH SKIES TRENDING MOCLR/
DIMINISHING WINDS AND PWAT FALLING TO 0.15-0.20 INCH OR 75 PCT OF
NORMAL LATE...EXPECT A FAIRLY STEEP DIURNAL FALL OF TEMP TOWARD THE
LO END OF GUIDANCE AWAY FM LK MODERATION.
.LONG TERM...SUNDAY THROUGH THURSDAY
SUN INTO SUN NIGHT...AS THE MID/UPPER LEVEL RIDGE BUILDS FROM THE
NORTHERN PLAINS INTO THE UPPER MS VALLEY...WRLY SFC WINDS WILL
INCREASE BTWN HIGH PRES OVER THE PLAINS AND LOW PRES OVER NE CANADA.
FCST SOUNDINGS SHOW A DRY PROFILE WITH ONLY SOME MID LEVEL MOISTURE
AS THE 925-850 MB THERMAL RIDGE EXTENDS INTO THE NRN GREAT LAKES.
EVEN WITH SOME MID CLOUDS POSSIBLE...EXPECT ENOUGH SUNSHINE TO HELP
BOOST TEMPS WELL ABOVE NORMAL WITH MAX TEMPS IN THE UPPER 30S AND TO
AROUND 40 IN DOWNSLOPE FLOW LOCATIONS. THE WEST WINDS WILL ALSO KEEP
TEMPS FROM FALLING OFF AS FAR WITH MIN TEMPS MAINLY IN THE 20S.
MON THROUGH WED...MODELS WERE IN BETTER AGREEMENT WITH THE SHALLOW
COLD AIR INTRUSION MON NIGHT INTO TUE BEHIND A COLD FRONT. EVEN
THOUGH 925-900 MB TEMPS FALL TO AROUND -17C...INVERSION HEIGHTS AOB
4K FT AND VERY DRY AIR UPSTREAM...WILL NOT BE FAVORABLE FOR SIGNIFICANT LES.
SO....WILL KEEP LOWER END CHANCE POPS FOR NRLY FLOW LES MON NIGHT
INTO TUE. HIGH PRES IS EXPECTED TO BUILD INTO THE REGION LATE TUE
INTO WED...BRINGING AN END TO ANY LES WITH MAINLY DRY CONDITIONS TUE
INTO WED.
THU...THE MODELS HAVE SHOWN CONSIDERABLE VARIATION WITH THE EXTENT
OF COLD AIR MOVING IN ON THE EDGE OF THE POLAR VORTEX DROPPING INTO
ERN CANADA. THE 00Z/03 ECMWF WAS MUCH LESS AGGRESSIVE WITH THE
COLDER AIR COMPARED TO THE 12/02 RUN AND IS CLOSER TO ITS ENS MEAN
AND THE GFS/GFS ENS MEAN...SHOWING 850 MB TEMPS TO AROUND -16C BY
12Z/FRI. THE COLDEST AIR AND BEST CHANCE FOR LES WOULD ARRIVE MAINLY
AFTER THE FCST PERIOD INTO FRI.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
CONTINUED ISSUES WITH CIG THIS PERIOD AS CONVOLUTED CLOUD PATTERN
REMAINS...ESPECIALLY ACROSS WESTERN UPPER MI. DRY PATCH OF AIR HAS
MOVED OVER WESTERN LAKE SUPERIOR THIS EVENING AND HAS ATTEMPTED TO
PUSH ONSHORE AT BOTH CMX AND IWD. SATELLITE IMAGERY SHOWS THIS HOLE
FILLING IN...SO DO NOT ANTICIPATE CMX OR IWD TO CLEAR OUT/REACH VFR
LEVELS FOR VERY LONG...IF AT ALL. SAW SHOULD REMAIN AT LOW MVFR CIG
THROUGH THE NIGHT. AS FOR VIS...CLOUDS HAVE MODERATED TEMPS MORE THAN
ANTICIPATED...SO LITTLE DECREASE IN VIS IS EXPECTED. ALL SITES SHOULD
SEE GRADUAL IMPROVEMENT BY FRIDAY AFTERNOON AS LOW LEVEL MOISTURE
MIXES OUT AND DRIER AIR ARRIVES.
&&
.MARINE...A SURFACE RIDGE WILL REMAIN IN CONTROL THROUGH EARLY
SUNDAY NIGHT KEEPING WINDS AND WAVES FAIRLY LIGHT. WESTERLY WINDS
ARE EXPECTED TO INCREASE INTO THE 15 TO 25 KT RANGE LATE SUN INTO
SUN NIGHT AS THE RIDGE MOVES TO THE SOUTH TOWARD THE SRN LAKES AND
OHIO VALLEY. THE NEXT CHANCE OF INCREASED WAVE HEIGHT AND WIND GUSTS
WILL BE MONDAY NIGHT INTO TUESDAY AS PRESSURE GRADIENT INCREASES
BETWEEN HIGH PRESSURE OVER SASKATCHEWAN AND LOW PRESSURE OVER
CENTRAL QUEBEC AS A COLD FRONT DROPS SOUTH THROUGH THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLB
AVIATION...TK
MARINE...JLB
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
323 AM CST FRI FEB 3 2012
.DISCUSSION...
/310 AM CST FRI FEB 3 2012/
WET WEATHER STILL ON TAP FOR THE NEXT SEVERAL DAYS COURTESY OF THE
UPPER LOW SPINNING NEAR THE CO/NM BORDER. THE MODELS ARE IN PRETTY
DECENT AGREEMENT THROUGH THE FIRST 48H TRACKING THE UPPER LOW
THROUGH THE CENTRAL ROCKIES TODAY AND TO FAR NE KS BY SATURDAY
EVENING. IN RESPONSE THE ASSOCIATED SURFACE LOW WILL TRACK FROM
WESTERN TEXAS INTO SE KS BY DAYBREAK SATURDAY AND TO EXTREME
SOUTHERN IL BY EARLY SATURDAY EVENING.
THE INITIAL FORECAST PROBLEM WITH THIS SYSTEM IS THE TIMING OF THE
ONSET OF PRECIPITATION. THE MAJORITY OF THE LATEST MODEL RUNS HAVE
SLOWED THE EASTWARD DEVELOPMENT TODAY WITH THE NAM SUGGESTING THAT
RAIN WILL ONLY GET INTO CENTRAL MO BEFORE 00Z TONIGHT...WHILE THE
OTHER MODEL GUIDANCE BRINGS IT TO OR JUST EAST OF THE MS RIVER.
WHILE I`M INCLINED TO BELIEVE THIS MORNING WILL BE DRY...I THINK
RAIN WILL REALLY GET GOING THIS AFTERNOON AS LARGE SCALE ASCENT
OVERSPREADS MO AND MOISTURE TRANSPORT ACCELERATES DUE TO THE
INCREASINGLY SOUTHERLY LLJ. THE LAST HRRR RUN ALSO SUPPORTS THIS
NOTION...WITH RAIN MAKING IT TO THE MS RIVER BY 00Z...WHILE LOW
LEVEL DRY HOLDS IT AT BAY UNTIL THIS EVENING OVER MUCH OF IL. RAIN
WILL THEN SPREAD ACROSS IL THIS EVENING IN CONCERT WITH THE
ADVANCING STORM SYSTEM AND EASTWARD SHIFT OF LIFT AND MOISTURE
TRANSPORT. THE GUIDANCE CONTINUES TO SHOW ELEVATED INSTABILITY
SUPPORTING THE POTENTIAL FOR SOME EMBEDDED THUNDERSTORMS WITH
LOCALLY HEAVY RAIN.
DESPITE A RATHER BLOCKY UPPER AIR PATTERN THAT ENSUES ACROSS THE
WESTERN CONUS OVER THE NEXT TWO DAYS...IT APPEARS THAT UPPER LOW
WILL REMAIN PROGRESSIVE GETTING PICKED UP A NORTHERN STREAM UPPER
TROF DIGGING INTO THE EASTERN U.S. ON SATURDAY NIGHT. THIS SHOULD
AT LEAST SHUNT THE DYING UPPER LOW SEWD THROUGH THE AREA SATURDAY
NIGHT INTO SUNDAY. THIS ALLOWS SOME DEEPER COLD AIR TO INFILTRATE
ON SATURDAY NIGHT IN THE WAKE OF THE LOW LEVEL CYCLONE...BUT THE
SNOW POTENTIAL STILL LOOKS IFFY AND AT THIS POINT WILL JUST KEEP
WITH THE CURRENT FORECAST OF A CHANCE OF RAIN OR SNOW.
GLASS
&&
.AVIATION...
/1115 PM CST THU FEB 2 2012/
00Z MODEL RUNS ARE CONTINUING TRENDS OF 18Z RUNS IN SLOWING THE E
PROGRESSION OF RAIN ACROSS THE AREA ON FRIDAY. THEREFORE HAVE
DELAYED ONSET OF WET WEATHER IN MOST AREAS BY A COUPLE OF
HOURS...WITH RAIN MOVING INTO MID MISSOURI AROUND MIDDAY...AND
THEN WORKING TO THE MISSISSIPPI RIVER JUST BEFORE SUNSET. FORECAST
SOUNDINGS CERTAINLY SUGGEST THAT THE EXTREMELY DRY LOW LEVELS WILL
HOLD CIGS IN THE VFR RANGE THROUGH 00Z...WITH A FAIRLY DRAMATIC
LOWERING OCCURRING DURING THE EVENING AS THE LOW LEVELS SATURATE
WITH THE STEADY RAINFALL. THIS TREND CERTAINLY MAKES SENSE FROM A
SYNOPTIC STANDPOINT...AS ALL TAF LOCATIONS WILL REMAIN N OF A
STRONG WARM FRONT THAT SHOULD BE DRAPED FROM NE OK TO CENTRAL AR
BY FRIDAY EVENING...AND REMAIN IN A ZONE OF FAIRLY PRONOUNCED
ISENTROPIC LIFT. DID NOT DETERIORATE CONDITIONS AS DRAMATICALLY OR
QUICKLY AT UIN...AS DRY LOW LEVEL AIR WILL LINGER THERE THE LONGEST.
STILL UNCERTAIN AS TO TIMING/LOCATION OF PRIMARY THUNDERSTORM
THREAT...SO CONTINUE TO REFLECT THREAT AS CB CLOUD GROUP FOR NOW.
SPECIFICS FOR KSTL...MID AND HIGH LEVEL CLOUDINESS...AOA
8KFT...SHOULD PERSIST UNTIL LATE FRIDAY AFTERNOON. RAIN SHOULD
DEVELOP AROUND SUNSET AS MID LEVEL MOISTURE BEGINS TO INCREASE
RAPIDLY...AND THEN LOOK FOR A STEADY RAIN TO SET IN DURING THE
EVENING. BASED ON FORECAST SOUNDINGS...CIGS AND VSBYS SHOULD
BEGIN TO DETERIORATE AFTER 03Z AS LOW LEVELS SATURATE...AND THE
SOUNDINGS AS WELL AS MET AND MAV MOS ARE STRONGLY SUGGESTING IFR
CIGS AND LOW END MVFR VSBYS AFTER 06Z.
TRUETT
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
326 AM CST FRI FEB 3 2012
.SHORT TERM...THIS HAS BEEN A CHALLENGING FORECAST THE LAST
COUPLE OF NIGHTS...AND UNFORTUNATELY THE IMPENDING WINTER STORM
CONTINUES TO BE HANDLED RATHER POORLY BY THE DETERMINISTIC MODEL
SOLUTIONS. MODELS CONTINUE TO WOBBLE NORTH AND SOUTH WITH THE AREA
OF POTENTIAL HEAVY SNOW. THIS IS LIKELY DUE TO CONVECTION/TSTMS
ACROSS THE SOUTHERN PLAINS CAUSING OVERALL MASS FIELD CHANGES FROM
MODEL RUN TO MODEL RUN. FEEL THAT ANY ONE PARTICULAR DETERMINISTIC
MODEL SOLUTION IS NOT WORTHY OF BASING A FORECAST ON DUE TO THIS
VARIABILITY. WILL SIDE TOWARD MORE OF AN ENSEMBLE/SREF BASED
APPROACH TO MAKING ANY FORECAST CHANGES THIS MORNING...AND USE THE
DETERMINISTIC MODELS MORE OR LESS AS GUIDANCE. DID APPEAR THAT THE
00Z NAM INITIALIZED A BIT BETTER THAN THE 00Z GFS BASED OFF WATER
VAPOR AND TROPOSPHERIC HEIGHTS. 00Z NAM SHOWS A NICE TROP FOLD
OVER WESTERN KS BY THIS EVENING...AND THIS IS WHEN THE DEEPENING
OF THE H7 LOW BEGINS. ALL MODELS INDICATE THIS PROCESS...BUT
DETERMINISTIC SOLUTIONS ARE DIFFERING ON EXACTLY WHERE THIS
DEEPENING AND SUBSEQUENT DEFORMATION BAND SET UP. CURRENT RUN OF
THE HRRR SUGGEST THE FIRST HINTS OF THE DEFORMATION BAND FORMING
FROM THE MCCOOK TO NORTH PLATTE AREA BY THE MIDDLE OF THIS
AFTERNOON...AND THAT GIVES SOMEWHAT OF A CONFIDENCE BOOST TO THE
GOING FORECAST. GIVEN THE MODEL VARIABILITY...FEEL THE BEST PLAN
IS TO LET THE CURRENT WARNINGS AND ADVISORIES CONTINUE AS
ARE...AND ONLY MAKE MINOR CHANGES TO THE CURRENT FORECAST. NORTH
WINDS DO INCREASE SOME THIS AFTERNOON...WITH GUSTS UP TO 30 MPH
EXPECTED BY THIS EVENING AS THE SFC LOW DEEPENS IN KS. THIS WILL
CAUSE SOME AREAS OF BLOWING SNOW AND REDUCED VISIBILITY. TOTAL
SNOWFALL ACCUMULATIONS BY SATURDAY NIGHT ARE EXPECTED TO RANGE
FROM 6 TO 11 INCHES ALONG AND SOUTHEAST OF AN ERICSON TO STAPLETON
TO BIG SPRINGS LINE. AMOUNTS GRADUALLY TAPER NORTHWEST OF THIS
LINE...WITH ONLY AN INCH OR SO EXPECTED AT THE NEBRASKA SOUTH
DAKOTA STATE LINE.
.LONG TERM...12Z MONDAY THROUGH THURSDAY. NO MAJOR CHANGES TO THE
LONG TERM FORECAST. THE PROGRESSION AND OVERALL PERFORMANCE OF THE
UPPER LOW WILL HEAVILY DICTATE THE EXTENDED PERIOD...ESPECIALLY
SUNDAY AND MONDAY. WITH THE POTENTIAL OF SIGNIFICANT SNOW
ACCUMULATIONS ACROSS SOUTHWEST THROUGH SOUTH CENTRAL
NEBRASKA...GENERALLY KEPT LATEST HIGHS GOING...AND LOWERED MINS A
FEW DEGREES ACROSS THE EAST. TEMPERATURES TO REACH NEAR 35 ACROSS
THE SNOWPACK SOUTHWEST TO SOUTH CENTRAL NEBRASKA...WITH THE
POTENTIAL OF LOWER 40S ACROSS NORTHERN NEBRASKA WHERE LIGHT AMOUNTS
ARE EXPECTED. ATTENTION THEN TURNS TO A COLD FRONT AND ASSOCIATED
SHORTWAVE THAT WILL DROP SOUTH THROUGH THE NORTHERN HIGH PLAINS LATE
MONDAY NIGHT INTO TUESDAY. BESIDES COOLER TEMPERATURES WITH HIGHS
ONLY IN THE UPPER 20S TO LOWER 30S...THE LONG RANGE MODELS...MOST
NOTABLY THE GFS...DO GENERATE SPOTTY QPF AS THE WAVE EJECTS EAST.
MOST SHOULD BE FOCUSED NEAR THE FRONT RANGE OF WYOMING AND
COLORADO...BUT INTO THE ADJACENT PLAINS...INCLUDING SOUTHWEST
NEBRASKA...WHERE A SLIGHT CHANCE FOR LIGHT SNOW INTRODUCED TUESDAY.
REMAINDER OF EXTENDED CURRENTLY DRY...ALTHOUGH THE ECMWF DOES DROP
ANOTHER DISTURBANCE THROUGH THE CENTRAL HIGH PLAINS LATE WEDNESDAY
AND THURSDAY INCLUDING WESTERN NEBRASKA. THIS NOT SUPPORTED BY THE
GFS. TEMPERATURES SHOULD MODERATE TO THE MID 30S TO NEAR 40S
WEDNESDAY AND THE UPPER 30S/LOWERS 30S BY THURSDAY. IT SHOULD BE
NOTED THAT THE ARCTIC AIR WILL REMAIN WELL TO OUR NORTHEAST ACROSS
THE NORTHERN GREAT LAKES THURSDAY...AS UPPER RIDGING BECOMES
ESTABLISHED ACROSS THE WESTERN CONUS AND NORTHWESTERLY FLOW PREVAILS
ACROSS THE CENTRAL PLAINS.
&&
.AVIATION...DETERIORATING FLIGHT CONDITIONS FOR KLBF AS A STORM
SYSTEM EJECTS FROM THE SOUTH CENTRAL ROCKIES TOWARDS THE CENTRAL
PLAINS. EXPECT CURRENT OVC035 -RA AT KLBF...WITH RAIN MIXING WITH
SNOW BY 15Z...THEN -SN BY 18Z WITH IFR CEILINGS. ACROSS FAR
SOUTHWEST NEBRASKA /KIML...KOGA TERMINALS/ CHANGE OVER TO SNOW
SHOULD OCCUR BETWEEN 12Z-14Z. MODEL GUIDANCE CONTINUES TO INDICATE
THE POTENTIAL FOR BLOWING SNOW FROM SOUTHWEST NEBRASKA THROUGH
SOUTH CENTRAL NEBRASKA BY THIS AFTERNOON AS THE CHANGE OVER FROM
RAIN TO SNOW OCCURS. NORTHERLY WIND GUSTS EXCEEDING 20KTS WILL BE
POSSIBLE...WITH VISIBILITY VALUES POSSIBLY LOWERING BELOW 1SM AT
TIMES THROUGH TONIGHT AT LBF. FURTHER SOUTH AND WEST... VISIBILITY
BELOW A QUARTER MILE MAY BE POSSIBLE. ACROSS THE NORTHERN SAND
HILLS INCLUDING THE KVTN TERMINAL...MODEL SOLUTIONS SUGGEST THE
TREND OF THE SYSTEM HAS BEEN SOUTH...SO WILL ONLY A TEMPO FOR -SN
FROM 22Z-02Z/04TH. AT THIS TIME NOT EXPECTING SIGNIFICANT FLIGHT
DISRUPTIONS...WITH MVFR CEILINGS TO PREVAIL AFTER 20Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...BLIZZARD WARNING UNTIL 5 PM MST
SATURDAY FOR NEZ056>058-069.
WINTER STORM WARNING FROM 6 AM CST /5 AM MST/ THIS MORNING TO 6
PM CST /5 PM MST/ SATURDAY FOR NEZ022-026>029-035>038-059-070-
071.
WINTER WEATHER ADVISORY FROM 6 AM CST /5 AM MST/ THIS MORNING TO
6 PM CST /5 PM MST/ SATURDAY FOR NEZ008>010-023>025.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...ROBERG
AVIATION...ROBERG
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
247 AM CST FRI FEB 3 2012
.SHORT TERM...TODAY THROUGH MONDAY
247 AM CST FRI FEB 3 2012
THE MAIN FOCUS IN THE SHORT TERM IS WITH THE CLOUD COVER AND DENSE
FOG AND WHEN THEY MAY CLEAR OUT.
CURRENTLY...A CLOSED MID LEVEL LOW IS PROPAGATING THROUGH THE
EASTERN ROCKIES WITH A RIDGE AXIS OUT AHEAD OF IT RUNNING ALONG
THE MISSISSIPPI RIVER. AT THE SURFACE...AN ELONGATED RIDGE OF HIGH
PRESSURE STRETCHES FROM THE MID ATLANTIC STATES NORTHWEST THROUGH
THE GREAT LAKES ON INTO THE NORTHERN PLAINS WHILE A LOW STARTS TO
TAKE SHAPE OVER WESTERN TEXAS. A WIDESPREAD BANK OF LOW LEVEL
STRATUS AND FOG ARE IN PLACE FROM THE DAKOTAS INTO THE GREAT LAKES
DUE TO MOISTURE STUCK UNDER A STEEP LOW LEVEL INVERSION. THIS
INVERSION INCREASES IN ITS BASE AS YOU GO TO THE NORTHEAST WITH
THE 03.00Z DVN SOUNDING SHOWING THE INVERSION STARTING AT THE
GROUND...WHERE 1/4SM VISIBILITY WAS BEING REPORTED...WHILE THE
03.00Z GRB SOUNDING WAS A LITTLE OFF THE DECK STARTING AT
900MB...WHERE VISIBILITY WAS P6SM WITH AN OVERCAST STRATUS DECK
AROUND 1KFT.
VISIBILITIES HAVE BEEN THE LOWEST ALONG THE WESTERN FRINGE OF THE
SURFACE RIDGE AXIS WHERE WINDS ARE LIGHT AND THE LOW LEVEL
MOISTURE IS TRAPPED UNDER THIS SHALLOW INVERSION. 03.00Z NAM/GFS
AND 03.06Z RUC SOUNDINGS SHOW THIS INVERSION AND LOW LEVEL
MOISTURE HOLDING ON THROUGH MUCH OF THE DAY BEFORE TRYING TO MIX
OUT THIS LAYER THIS AFTERNOON. CONFIDENCE IN THIS MIXING OUT
OCCURRING IS FAIRLY LOW GIVEN THE MODELS RECENT TRACK RECORD IN
TRYING TO CLEAR THE SKIES OUT. THAT SAID...WINDS DO PICK UP A BIT
OUT OF THE NORTHEAST AS THE LOW PRESSURE SYSTEM STRENGTHENS TO THE
SOUTH WHICH COULD HELP WITH THE MIXING. THUS...FOR NOW HAVE LEFT
THE DENSE FOG ADVISORY GOING UNTIL 18Z TODAY...BUT HAVE CHOPPED
OFF A FEW TIERS OF COUNTIES ACROSS CENTRAL WISCONSIN WHICH HAVE
NOT HAD ANY VISIBILITY ISSUES AND DO NOT APPEAR LIKELY TO DROP
THROUGH THE MORNING.
HOW FAST THE CLOUDS CLEAR OUT WILL PLAY A HUGE ROLE IN TEMPERATURES
THROUGH THE WEEKEND. WHERE SKIES CLEARED OUT ON
THURSDAY...TEMPERATURES SPIKED UP INTO THE 40S AND BROKE A RECORD AT
ROCHESTER. EVEN IF THE LOW LEVEL CLOUDS SCOUR OUT TODAY...THERE
SHOULD STILL BE AMPLE HIGH LEVEL CLOUD COVER IN PLACE DUE TO THE
STORM SYSTEM TO THE SOUTH. WITH CLOUDS POSSIBLY HOLDING ON LONGER
THAN FORECAST...HAVE GONE A BIT PESSIMISTIC ON TEMPERATURES OVER THE
NEXT FEW DAYS.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY
247 AM CST FRI FEB 3 2012
A COLD FRONT DROPS DOWN THROUGH THE REGION MONDAY NIGHT BUT THERE
IS NOT MUCH FORCING OR MOISTURE WITH ITS PASSAGE...SO IT SHOULD
COME THROUGH DRY. WHILE TEMPERATURES WILL DROP BEHIND THE
FRONT...THE MAIN POCKET OF COLD AIR WITH 850MB TEMPERATURES OF
AROUND -20C WILL TRACK OFF TO THE EAST TOWARD NEW ENGLAND. BEYOND
THIS...THE ONLY CHANCE FOR ANY SNOW WILL BE ON WEDNESDAY AS THE
REMNANTS OF A CUT OFF MID LEVEL LOW GET PICKED UP BY THE UPPER
LEVEL FLOW. THE 03.00Z ECMWF IS DEEPER WITH THIS LOW COMPARED TO
THE 03.00Z GFS WHICH JUST BRINGS AN OPEN WAVE THROUGH THE REGION.
REGARDLESS...THIS JUST LEAVES FOR A SLIGHT CHANCE OF SNOW ACROSS
THE FAR SOUTHERN PORTION OF THE FORECAST AREA BUT BEARS WATCHING.
&&
.AVIATION...THROUGH 06Z SATURDAY
1133 PM CST THU FEB 2 2012
LIGHT EASTERLY FLOW AND SATURATED LOW LAYERS HAVE KEPT KRST WITH
VLIFR CEILINGS AND VISIBILITIES AND THIS TREND WILL CONTINUE
THROUGH AT LEAST 16Z FRIDAY. THIS EASTERLY FLOW HAVE KEPT
TEMPERATURE/DEW POINT SPREADS AT A FEW DEGREES AT KLSE WITH LOWER
MVFR CEILINGS AND VFR VISIBILITIES. 03.01Z RUC 975MB RELATIVE
HUMIDITY PROGS CONTINUE TO SHOW FURTHER SATURATION AT KLSE
THROUGH THE OVERNIGHT HOURS. STILL EXPECTING IFR CEILINGS AND
VISIBILITIES TO DEVELOP LATER TONIGHT. QUESTION THEN BECOMES IF
THE STRATUS WILL BREAK UP AT ALL ON FRIDAY AFTER 16Z. FLOW DOES
REMAIN RATHER LIGHT FROM THE NORTHEAST. 03.00Z NAM DOES SHOW SOME
DECREASE IN THE LOW LEVEL MOISTURE WITH THE NORTHEAST SURFACE
FLOW...ESPECIALLY OVER WISCONSIN. DO EXPECT CEILINGS TO RISE AT
KLSE...BUT REMAIN IN THE MVFR CATEGORY THROUGH 06Z. AT KRST NOT AS
CONFIDENT OF THE RISING CEILINGS OR VISIBILITIES. DID RAISE THE
CEILINGS INTO THE IFR CATEGORY AND THE VISIBILITIES INTO THE LOWER
MVFR CATEGORY. AS COLUMN COOLS ONCE AGAIN AFTER 00Z SATURDAY...MAY
SEE SOME FOG FORM ONCE AGAIN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
247 AM CST FRI FEB 3 2012
WI...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR WIZ032-033-041-
053>055-061.
MN...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR MNZ079-086>088-
094>096.
IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1133 PM CST THU FEB 2 2012
.SHORT TERM...TONIGHT THROUGH SATURDAY NIGHT
340 PM CST THU FEB 2 2012
AT 3 PM...THE WESTERN EXTENT OF THE LOW CLOUDS REMAINED EAST OF A
LINE FROM THE TWIN CITIES TO SAVANNA ILLINOIS /KSFY/. THE
COMBINATION OF SOUTHEAST WINDS JUST OFF THE SURFACE AND HIGH DEW
POINTS FOR THIS TIME OF YEAR...EXPECT THAT THE WESTERN EDGE OF
THIS CLOUD LINE WILL QUICKLY MOVE WEST EARLY THIS EVENING AND
QUICKLY LOWER. IN ADDITION...THE VISIBILITIES WILL QUICKLY FALL
AS THE TEMPERATURES RAPIDLY APPROACHES THE DEW POINTS THIS
EVENING. THIS WILL RESULT IN THE REDEVELOPMENT OF DENSE FOG ACROSS
THE AREA. THIS FOG WILL INITIALLY BECOME DENSE ON THE RIDGE TOPS
OF WESTERN WISCONSIN...SOUTHEAST MINNESOTA...AND NORTHEAST IOWA
EARLY THIS EVENING...AND THEN SETTLE INTO THE RIVER VALLEYS OF
WESTERN WISCONSIN DURING THE LATE EVENING AND OVERNIGHT. DUE TO
THIS...DECIDED TO GO WITH A DENSE FOG ADVISORY FOR TONIGHT AND
FRIDAY MORNING. WITH BOTH CLIMATOLOGY AND THE FOG TRENDS OVER THE
PAST TWO DAYS...DECIDED THAT NOON WOULD BE THE BEST ENDING TIME
FOR THE DENSE FOG ADVISORY.
WITH THE DEW POINTS AROUND 30...TEMPERATURES WILL HAVE A VERY HARD
TIME APPROACHING THE MOS TEMPERATURE GUIDANCE. AS A RESULT...
RAISED THE MINIMUM TEMPERATURES BY ONE CATEGORY.
FROM FRIDAY THROUGH SATURDAY NIGHT...THE 02.12Z MODELS CONTINUED A
TREND OF THE 01.18Z AND 02.00Z SHOWED AND IT SHIFTED THE LOW
PRESSURE SYSTEM A BIT FURTHER SOUTH AS A REX BLOCK DEVELOPS ACROSS
THE CANADIAN PRAIRIES AND CENTRAL PLAINS. THE HIGH ASSOCIATED WITH
THIS BLOCK WILL FORCE THE LOW PRESSURE SYSTEM FURTHER SOUTH...AND
AS RESULT THE PRECIPITATION REMAINS FROM SOUTHERN IOWA SOUTH TO
THE WESTERN GULF OF MEXICO. WITH THIS TREND BEING CONSISTENT...THE
PRECIPITATION CHANCES FOR THIS TIME PERIOD WAS REMOVED FROM THE
FORECAST.
.LONG TERM...SUNDAY THROUGH THURSDAY
340 PM CST THU FEB 2 2012
FROM SUNDAY THROUGH TUESDAY NIGHT...A PACIFIC HIGH PRESSURE SYSTEM
WILL REMAIN IN CONTROL OF THE WEATHER ACROSS THE AREA. THIS HIGH
WILL PROVIDE DRY WEATHER FOR THIS TIME PERIOD. WITH THE MOS
TEMPERATURE GUIDANCE BIAS BEING TOO COOL AND LOSS OF THE DEEPER
SNOW PACK...TEMPERATURES WERE ADJUSTED UPWARD BY ABOUT 3 DEGREES.
BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO STRUGGLE AS A
MODERATE TO STRONG NEGATIVE ARCTIC OSCILLATION DEVELOPS. THIS
WILL RESULT IN THE DEVELOPMENT OF AN AMPLIFIED TROUGH ACROSS
EASTERN CANADA...GREAT LAKES...AND NEW ENGLAND. THE MODELS
CONTINUE TO SHOW THAT THE ARCTIC AIR ASSOCIATED WITH THIS LONG
WAVE TROUGH WILL EITHER JUST BRIEFLY MOVE THROUGH THE AREA OR
REMAIN TO OUR EAST. THIS ACTUALLY FITS IN WELL WITH A COMPOSITE
ANALYSIS WHICH SHOWS NO STRONG STATISTICAL SIGNAL BETWEEN THE
PHASE OF THE ARCTIC OSCILLATION AND THE AVERAGE FEBRUARY
TEMPERATURES FOR OUR AREA OF THE COUNTRY. THE WESTERN EXTENT OF
THIS TROUGH WILL BE GREATLY AFFECTED BY THE TELECONNECTION WITH THE
ANOMALOUS THUNDERSTORM ACTIVITY THAT IS CONTINUING TO OCCUR ACROSS
INDONESIA AND THE WESTERN PACIFIC. SINCE THIS CONVECTION IS VERY
SIMILAR TO WHAT WOULD BE SEEN IN PHASE 5. DURING THIS PHASE...LONG
WAVE TROUGHS TYPICALLY HAVE A HARD TIME MAINTAINING THEMSELVES
ACROSS THE MID AND UPPER MISSISSIPPI RIVER VALLEY. THIS IS IN
VERY GOOD AGREEMENT WITH THE CFS VERSION 2 WHICH HAS BEEN SHOWING
THIS SCENARIO CONSISTENTLY FOR THE PAST TWO WEEKS. FOR THE TIME
BEING...JUST COOLED THE TEMPERATURES TO EITHER SLIGHTLY BELOW OR
NEAR NORMAL FROM WEDNESDAY THROUGH THURSDAY.
&&
.AVIATION...THROUGH 06Z SATURDAY
1133 PM CST THU FEB 2 2012
LIGHT EASTERLY FLOW AND SATURATED LOW LAYERS HAVE KEPT KRST WITH
VLIFR CEILINGS AND VISIBILITIES AND THIS TREND WILL CONTINUE
THROUGH AT LEAST 16Z FRIDAY. THIS EASTERLY FLOW HAVE KEPT
TEMPERATURE/DEW POINT SPREADS AT A FEW DEGREES AT KLSE WITH LOWER
MVFR CEILINGS AND VFR VISIBILITIES. 03.01Z RUC 975MB RELATIVE
HUMIDITY PROGS CONTINUE TO SHOW FURTHER SATURATION AT KLSE
THROUGH THE OVERNIGHT HOURS. STILL EXPECTING IFR CEILINGS AND
VISIBILITIES TO DEVELOP LATER TONIGHT. QUESTION THEN BECOMES IF
THE STRATUS WILL BREAK UP AT ALL ON FRIDAY AFTER 16Z. FLOW DOES
REMAIN RATHER LIGHT FROM THE NORTHEAST. 03.00Z NAM DOES SHOW SOME
DECREASE IN THE LOW LEVEL MOISTURE WITH THE NORTHEAST SURFACE
FLOW...ESPECIALLY OVER WISCONSIN. DO EXPECT CEILINGS TO RISE AT
KLSE...BUT REMAIN IN THE MVFR CATEGORY THROUGH 06Z. AT KRST NOT AS
CONFIDENT OF THE RISING CEILINGS OR VISIBILITIES. DID RAISE THE
CEILINGS INTO THE IFR CATEGORY AND THE VISIBILITIES INTO THE LOWER
MVFR CATEGORY. AS COLUMN COOLS ONCE AGAIN AFTER 00Z SATURDAY...MAY
SEE SOME FOG FORM ONCE AGAIN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
248 PM CST THU FEB 2 2012
WI...DENSE FOG ADVISORY UNTIL NOON CST FRIDAY FOR WIZ041>044-053>055-
061.
DENSE FOG ADVISORY FROM 6 PM THIS EVENING TO NOON CST FRIDAY FOR
WIZ017-029-032>034.
MN...DENSE FOG ADVISORY UNTIL NOON CST FRIDAY FOR MNZ096.
DENSE FOG ADVISORY FROM 6 PM THIS EVENING TO NOON CST FRIDAY FOR
MNZ079-086>088-094-095.
IA...DENSE FOG ADVISORY UNTIL NOON CST FRIDAY FOR IAZ009>011-019-029-
030.
DENSE FOG ADVISORY FROM 6 PM THIS EVENING TO NOON CST FRIDAY FOR
IAZ008-018.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
1100 PM MST THU FEB 2 2012
.AVIATION...06Z TAF ISSUANCE...
SNOW CONTINUES TO FALL ACROSS EASTERN COLORADO AND SOUTHEAST
WYOMING AS OF 05Z. VISIBILITIES ACROSS SOUTHEAST WYOMING AT THIS
TIME AS LOW AS 1/2 SM. THESE LOW VISIBILITIES WILL CONTINUE INTO
THE OVERNIGHT HOURS BUT ARE EXPECTED TO IMPROVE TOWARDS SUNRISE AS
SNOWFALL RATES DECREASE. INTO SOUTHERN PORTIONS OF THE NEBRASKA
THE NEBRASKA PANHANDLE SNOW WILL DEVELOPS LATER TONIGHT AND
CONTINUE THROUGH THE DAY SATURDAY. IFR TO LIFR IS EXPECTED WITH
PERIODS OF HEAVY SNOW AND STRONG NORTHERLY WINDS. BFF AND AIA ARE
EXPECTED TO BE NEAR THE NORTHERN EDGE OF THE SNOW AND THUS CIGS
AND VISIBILITIES ARE UNCERTAIN FOR THOSE LOCATIONS...HOWEVER SNY
IS EXPECTED TO BE LOCATED UNDER THE HEAVIER SNOW WITH
SIGNIFICANTLY REDUCED CIGS AND VISBYS. SNOW WILL END FROM WEST TO
EAST ACROSS THE FORECAST AREA FROM LATE FRIDAY AFTERNOON INTO
SATURDAY MORNING.
&&
.PREV DISCUSSION... /ISSUED 929 PM MST THU FEB 2 2012/
DISCUSSION...
SNOW CONTINUES TO INCREASE IN COVERAGE AND INTENSITY ACROSS MUCH
OF THE REGION AS A VIGOROUS UPPER-LEVEL LOW PRESSURE SYSTEM
DEEPENS OVER THE FOUR CORNERS REGION. THE MID-LEVEL CIRCULATION IS
NOW VERY EVIDENT ON REGIONAL WATER VAPOR SATELLITE IMAGERY...ALONG
WITH A PRONOUNCED DRY SLOT EJECTING NORTHEASTWARD ACROSS SOUTHEAST
COLORADO INTO NORTHWEST KANSAS. AN ASSOCIATED SURFACE LOW WAS
ANALYZED OVER SOUTHEAST NEW MEXICO...WITH AN INVERTED TROUGH
EXTENDING NORTHWARD INTO WESTERN NEBRASKA. THIS...COMBINED WITH A
MID-LEVEL DEFORMATION FIELD OVER WESTERN NEBRASKA...HAS RESULTED
IN DEEP/MOIST UPSLOPE FLOW OVER SOUTHEAST WYOMING AND THE WESTERN
NEBRASKA PANHANDLE...WITH WIDESPREAD LIGHT TO MODERATE SNOW
DEVELOPING AS A RESULT.
STRONG RADAR ECHOS ALONG THE WYOMING/NEBRASKA STATE LINE HAVE
FAILED TO YIELD NOTABLE SNOWFALL TOTALS OVER THE LAST SEVERAL
HOURS OWING TO WARM TEMPERATURES AND LARGE / 20F TO 25 F /
DEWPOINT SPREADS. THE GREATEST SNOW RATES HAVE BEEN OBSERVED ALONG
AND JUST EAST OF THE LARAMIE RANGE FROM CHEYENNE NORTH TO
WHEATLAND...WHERE 1 TO 3 INCHES OF SNOW HAS RESULTED FROM DEEP
MOISTURE AND STRONG UPWARD VERTICAL MOTION THROUGH THE DENDRITIC
GROWTH ZONE. WE WENT AHEAD AND INCREASED PRECIPITATION CHANCES TO
NEAR 100 PERCENT ACROSS THESE AREAS...BUT MAINTAINED LOWER POPS IN
THE SHADOWED AREAS WEST OF THE LARAMIE RANGE. THE STRONGEST
DYNAMICS AND FAVORABLE MID-LEVEL TROWAL ARE STILL EXPECTED TO
REMAIN WELL TO THE SOUTHEAST OF THE REGION...LIKELY LIMITING
OVERALL SNOWFALL ACCUMULATIONS. EVEN SO...ONGOING HEADLINES LOOK
GOOD WITH THE POTENTIAL FOR GUSTY WIND AND SIGNIFICANT
SNOWFALL...ESPECIALLY OVER THE SOUTHERN PANHANDLE.
WE ALSO WENT AHEAD AND INCREASED FORECAST LOW TEMPERATURES ACROSS
MUCH OF THE FORECAST AREA. SIGNIFICANT LOW-LEVEL MOISTURE WITH
HIGH SPECIFIC HUMIDITIES IN THE H7-H85 LAYER AND SURFACE DEWPOINTS
AT OR ABOVE 20F COMBINED WITH MODEST LOW-LEVEL WARM AIR ADVECTION
AND WIDESPREAD DENSE CLOUD COVER SHOULD NOT ALLOW TEMPERATURES TO
FALL BELOW 20F ALONG AND EAST OF THE LARAMIE RANGE.
HAMMER/LIEBL
PREV DISCUSSION... /ISSUED 557 PM MST THU FEB 2 2012/
UPDATE...
SNOW IS RAPIDLY DEVELOPING ACROSS SOUTHEAST WYOMING THIS EVENING.
SNOW WILL BECOME HEAVY AT TIMES...ESPECIALLY THIS EVENING. THESE
HIGH SNOW RATES WILL AFFECT MUCH OF INTERSTATE 80 AND 25 ACROSS
SOUTHEAST WYOMING. DESPITE IMPRESSIVE RADAR RETURNS OVER THE
NEBRASKA PANHANDLE...PRECIPITATION HAS YET TO REACH THE
GROUND. DEW POINT DEPRESSIONS STILL 20-25 DEGREES BELOW THE
STRONGEST RADAR RETURNS...BUT CEILINGS HAVE BEEN DROPPING SO SOME
SNOW SHOULD START HITTING THE GROUND NEAR THE WYOMING AND NEBRASKA
BORDER IN THE NEXT FEW HOURS. DRY NORTHEAST FLOW AT ALLIANCE AND
SCOTTSBLUFF MAY BE ENOUGH TO KEEP SNOW AT BAY UNTIL AFTER SUNRISE
FRIDAY...WHEN THE MAIN UPPER LOW EJECTS INTO THE PLAINS AND WRAP
AROUND SNOW LIFTS INTO THE AREA OUT OF COLORADO. ALL IN ALL
FORECAST ON TRACK WITH NO BIG CHANGES EXPECTED AT THIS TIME.
AVIATION...00Z TAF ISSUANCE...
SNOW WILL SPREAD ACROSS SOUTHEAST WYOMING THIS EVENING...
SIGNIFICANTLY REDUCING VISIBILITIES. THE HEAVIEST SNOW WILL BE
FOUND ALONG THE FOOTHILLS OF THE LARAMIE RANGE WHERE VISIBILITIES
WILL DROP BELOW 1/2 SM FROM MUCH OF TONIGHT. CYS WILL SEE THE
GREATEST IMPACT OF ALL TAF SITES TONIGHT. LAR WILL ALSO SEE
REDUCED VISIBILITIES BUT THE DURATION SHOULD BE SHORTER LIVED.
CDR AND AIA MOST LIKELY WILL BE EAST OF THE MAIN SNOW SHIELD
TONIGHT...WITH MVFR DEVELOPING.
PREV DISCUSSION... /ISSUED 325 PM MST THU FEB 2 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
HAZARDOUS WINTER STORM CONTINUES TO LOOK ON TRACK TO ARRIVE THIS
EVENING ACROSS SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. 500MB RUC ANALYSIS AT 20Z SHOWS THE MIDLEVEL TROUGH
CLOSING OFF TO THE EAST OF THE FOUR CORNERS REGION. UPPER LEVEL
DIVERGENCE TO THE NORTHEAST OF THE LOW IS CURRENTLY PRODUCING AN
AREA OF IR ENHANCEMENT STRETCHING FROM DENVER TO GOODLAND. THE
MODELS AGREE IN INCREASING LLVL N-NE UPSLOPE WINDS THRU THE EVENING
AND MOISTENING THE LOW/MID LEVELS. WHILE THE CURRENT DEWPOINT
DEPRESSIONS ARE HIGH TO THE EAST OF THE LARAMIE RANGE (15-20F)...LOW
LEVEL COLD-AIR ADVECTION AND TOP-DOWN MOISTENING WILL RESULT IN
SATURATION BY THIS EVENING. LOOKS LIKE THE PERIOD FROM 00Z-06Z IN
PARTICULAR IS FAVORABLE FOR HIGH SNOWFALL RATES ACROSS SOUTHEAST WY.
A BUFKIT TIME-HEIGHT PLOT FROM KCYS SHOWS THE COMBINATION OF
EASTERLY 700MB WINDS AND UPWARD MOTION IN THE DENDRITE GROWTH ZONE
BEING MAXIMIZED BETWEEN 00Z-06Z. SNOWFALL ACROSS THE NE PANHANDLE
WILL LIKELY HOLD OFF UNTIL LATE TONIGHT WHEN THE MIDLEVEL DYNAMICS
ARRIVE.
THE 500MB LOW WILL BEGIN ITS PROGRESSION TO THE NORTHEAST ON
FRIDAY MOVING...MOVING ACROSS EASTERN CO AND NORTHWESTERN KS. THE
HEAVIEST SNOWFALL ON FRIDAY...ESPECIALLY BY AFTN...IS EXPECTED OVER
THE SOUTHERN PART OF THE NEBRASKA PANHANDLE CLOSEST TO THE 700MB
LOW. 700MB FCTS AT 18Z FRI SHOW AN AXIS OF HIGHER NE WINDS (AROUND
35 KTS) STRETCHING ACROSS CHEYENNE COUNTY. BUFKIT SOUNDINGS AT KSNY
AT 18Z SUPPORT GUSTS TO 35 KTS...THUS WILL CONTINUE THE BLIZZARD
WARNING ACROSS CHEYENNE COUNTY. ANY SUBSTANTIAL MIDLEVEL
FRONTOGENESIS IS PROGGED TO BE SOUTH AND EAST OF THE CWA THROUGHOUT
THE ENTIRE EVENT. THUS...NOT EXPECTING OVERLY HIGH SNOWFALL
RATES...HOWEVER THE LONG DURATION OF LOW-LEVEL UPSLOPE WILL PRODUCE
STORM TOTAL SNOWFALL AMOUNTS BETWEEN 7 TO 10 INCHES ALONG INTERSTATE
80 THROUGH FRIDAY NIGHT. EXPECT HIGHER AMOUNTS IN THE
OROGRAPHICALLY FAVORED SOUTH LARAMIE RANGE NEAR THE I-80 SUMMIT.
AMOUNTS WILL DROP OFF TO THE NORTH AND WEST...IN AREAS FURTHER
REMOVED FROM THE MIDLEVEL LOW. SNOW WILL BEGIN TO TAPER OFF FROM
WEST TO EAST OVER THE CWA BY LATE FRIDAY NIGHT AS THE MAIN 500MB LOW
CONTINUES ITS PROGRESSION EASTWARD AND THE SFC HIGH SETTLES OVER
SOUTHEAST WY.
LONG TERM...SATURDAY THROUGH THURSDAY
12Z GFS AND ECMWF 500 MB SYNOPTIC PATTERNS SIMILAR...LEADING TO
MODERATE TO HIGH CONFIDENCE IN THEIR RESPECTIVE MODEL SOLUTIONS.
SATURDAY...SHORTWAVE TROUGH ALOFT WILL BE MOVING OFF TO OUR
EAST...THUS DECREASING SNOW CHANCES ACROSS OUR SOUTHERN COUNTIES.
SUNDAY...SLOW WARMING TREND ON TAP AS HEIGHTS AND THICKNESSES RISE.
DRY WITH LACK OF LOW AND MID LEVEL MOISTURE.
MONDAY...ANOTHER WEAK COLD FRONT MOVES SOUTH ACROSS OUR
COUNTIES...THOUGH THE BULK OF THE COLDER AIR WILL REMAIN NORTH AND
EAST OF OUR AREA. CONTINUED DRY WITH LIMITED LOW AND MID LEVEL
MOISTURE.
TUESDAY-THURSDAY...DRY NORTHWEST FLOW ALOFT WILL PREVAIL. WARMING
TREND WILL CONTINUE AS HEIGHTS AND THICKNESSES RISE.
AVIATION...18Z TAFS
THROUGH 00Z...CIGS AND VISIBILITIES LOWERING
TO IFR IN SNOW AND FOG ACROSS CARBON COUNTY WITH MOUNTAIN
OBSCURATION. VFR ELSEWHERE.
AFTER 00Z...WIDESPREAD IFR AND LIFR DEVELOPING IN SNOW AND FOG
AT RAWLINS...LARAMIE...CHEYENNE AND SIDNEY ALONG WITH MOUNTAIN
OBSCURATION. MVFR DUE TO CLOUDS...SNOW AND FOG DEVELOPING AT
CHADRON...SCOTTSBLUFF AND ALLIANCE.
AFTER 12Z...WIDESPREAD IFR IN SNOW AND FOG...WITH LIFR AND VLIFR AT
TIMES AT LARAMIE...CHEYENNE AND SIDNEY. MOUNTAINS OBSCURED. RUBIN
FIRE WEATHER...NO FIRE WEATHER CONCERNS
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 11 PM FRIDAY FOR WYZ106-WYZ107-WYZ116-
WYZ117-WYZ118-WYZ119.
WINTER WEATHER ADVISORY UNTIL 5 PM FRIDAY FOR WYZ103-WYZ114-
WYZ115.
WINTER WEATHER ADVISORY UNTIL 11 PM FRIDAY FOR WYZ108.
NE...WINTER WEATHER ADVISORY UNTIL 11 PM FRIDAY FOR NEZ003-NEZ019-
NEZ096.
WINTER STORM WARNING UNTIL 11 PM FRIDAY FOR NEZ020-NEZ021-NEZ054.
BLIZZARD WARNING UNTIL 11 PM FRIDAY FOR NEZ055.
&&
$$
UPDATE...HAMMER/LIEBL
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM...RUBIN
AVIATION...LIEBL
AREA FORECAST DISCUSSION
NWS CHEYENNE WY
929 PM MST THU FEB 2 2012
.DISCUSSION...
SNOW CONTINUES TO INCREASE IN COVERAGE AND INTENSITY ACROSS MUCH
OF THE REGION AS A VIGOROUS UPPER-LEVEL LOW PRESSURE SYSTEM
DEEPENS OVER THE FOUR CORNERS REGION. THE MID-LEVEL CIRCULATION IS
NOW VERY EVIDENT ON REGIONAL WATER VAPOR SATELLITE IMAGERY...ALONG
WITH A PRONOUNCED DRY SLOT EJECTING NORTHEASTWARD ACROSS SOUTHEAST
COLORADO INTO NORTHWEST KANSAS. AN ASSOCIATED SURFACE LOW WAS
ANALYZED OVER SOUTHEAST NEW MEXICO...WITH AN INVERTED TROUGH
EXTENDING NORTHWARD INTO WESTERN NEBRASKA. THIS...COMBINED WITH A
MID-LEVEL DEFORMATION FIELD OVER WESTERN NEBRASKA...HAS RESULTED
IN DEEP/MOIST UPSLOPE FLOW OVER SOUTHEAST WYOMING AND THE WESTERN
NEBRASKA PANHANDLE...WITH WIDESPREAD LIGHT TO MODERATE SNOW
DEVELOPING AS A RESULT.
STRONG RADAR ECHOS ALONG THE WYOMING/NEBRASKA STATE LINE HAVE
FAILED TO YIELD NOTABLE SNOWFALL TOTALS OVER THE LAST SEVERAL
HOURS OWING TO WARM TEMPERATURES AND LARGE / 20F TO 25 F /
DEWPOINT SPREADS. THE GREATEST SNOW RATES HAVE BEEN OBSERVED ALONG
AND JUST EAST OF THE LARAMIE RANGE FROM CHEYENNE NORTH TO
WHEATLAND...WHERE 1 TO 3 INCHES OF SNOW HAS RESULTED FROM DEEP
MOISTURE AND STRONG UPWARD VERTICAL MOTION THROUGH THE DENDRITIC
GROWTH ZONE. WE WENT AHEAD AND INCREASED PRECIPITATION CHANCES TO
NEAR 100 PERCENT ACROSS THESE AREAS...BUT MAINTAINED LOWER POPS IN
THE SHADOWED AREAS WEST OF THE LARAMIE RANGE. THE STRONGEST
DYNAMICS AND FAVORABLE MID-LEVEL TROWAL ARE STILL EXPECTED TO
REMAIN WELL TO THE SOUTHEAST OF THE REGION...LIKELY LIMITING
OVERALL SNOWFALL ACCUMULATIONS. EVEN SO...ONGOING HEADLINES LOOK
GOOD WITH THE POTENTIAL FOR GUSTY WIND AND SIGNIFICANT
SNOWFALL...ESPECIALLY OVER THE SOUTHERN PANHANDLE.
WE ALSO WENT AHEAD AND INCREASED FORECAST LOW TEMPERATURES ACROSS
MUCH OF THE FORECAST AREA. SIGNIFICANT LOW-LEVEL MOISTURE WITH
HIGH SPECIFIC HUMIDITIES IN THE H7-H85 LAYER AND SURFACE DEWPOINTS
AT OR ABOVE 20F COMBINED WITH MODEST LOW-LEVEL WARM AIR ADVECTION
AND WIDESPREAD DENSE CLOUD COVER SHOULD NOT ALLOW TEMPERATURES TO
FALL BELOW 20F ALONG AND EAST OF THE LARAMIE RANGE.
HAMMER/LIEBL
&&
.PREV DISCUSSION... /ISSUED 557 PM MST THU FEB 2 2012/
UPDATE...
SNOW IS RAPIDLY DEVELOPING ACROSS SOUTHEAST WYOMING THIS EVENING.
SNOW WILL BECOME HEAVY AT TIMES...ESPECIALLY THIS EVENING. THESE
HIGH SNOW RATES WILL AFFECT MUCH OF INTERSTATE 80 AND 25 ACROSS
SOUTHEAST WYOMING. DESPITE IMPRESSIVE RADAR RETURNS OVER THE
NEBRASKA PANHANDLE...PRECIPITATION HAS YET TO REACH THE
GROUND. DEW POINT DEPRESSIONS STILL 20-25 DEGREES BELOW THE
STRONGEST RADAR RETURNS...BUT CEILINGS HAVE BEEN DROPPING SO SOME
SNOW SHOULD START HITTING THE GROUND NEAR THE WYOMING AND NEBRASKA
BORDER IN THE NEXT FEW HOURS. DRY NORTHEAST FLOW AT ALLIANCE AND
SCOTTSBLUFF MAY BE ENOUGH TO KEEP SNOW AT BAY UNTIL AFTER SUNRISE
FRIDAY...WHEN THE MAIN UPPER LOW EJECTS INTO THE PLAINS AND WRAP
AROUND SNOW LIFTS INTO THE AREA OUT OF COLORADO. ALL IN ALL
FORECAST ON TRACK WITH NO BIG CHANGES EXPECTED AT THIS TIME.
AVIATION...00Z TAF ISSUANCE...
SNOW WILL SPREAD ACROSS SOUTHEAST WYOMING THIS EVENING...
SIGNIFICANTLY REDUCING VISIBILITIES. THE HEAVIEST SNOW WILL BE
FOUND ALONG THE FOOTHILLS OF THE LARAMIE RANGE WHERE VISIBILITIES
WILL DROP BELOW 1/2 SM FROM MUCH OF TONIGHT. CYS WILL SEE THE
GREATEST IMPACT OF ALL TAF SITES TONIGHT. LAR WILL ALSO SEE
REDUCED VISIBILITIES BUT THE DURATION SHOULD BE SHORTER LIVED.
CDR AND AIA MOST LIKELY WILL BE EAST OF THE MAIN SNOW SHIELD
TONIGHT...WITH MVFR DEVELOPING.
PREV DISCUSSION... /ISSUED 325 PM MST THU FEB 2 2012/
SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT
HAZARDOUS WINTER STORM CONTINUES TO LOOK ON TRACK TO ARRIVE THIS
EVENING ACROSS SOUTHEAST WYOMING AND THE WESTERN NEBRASKA
PANHANDLE. 500MB RUC ANALYSIS AT 20Z SHOWS THE MIDLEVEL TROUGH
CLOSING OFF TO THE EAST OF THE FOUR CORNERS REGION. UPPER LEVEL
DIVERGENCE TO THE NORTHEAST OF THE LOW IS CURRENTLY PRODUCING AN
AREA OF IR ENHANCEMENT STRETCHING FROM DENVER TO GOODLAND. THE
MODELS AGREE IN INCREASING LLVL N-NE UPSLOPE WINDS THRU THE EVENING
AND MOISTENING THE LOW/MID LEVELS. WHILE THE CURRENT DEWPOINT
DEPRESSIONS ARE HIGH TO THE EAST OF THE LARAMIE RANGE (15-20F)...LOW
LEVEL COLD-AIR ADVECTION AND TOP-DOWN MOISTENING WILL RESULT IN
SATURATION BY THIS EVENING. LOOKS LIKE THE PERIOD FROM 00Z-06Z IN
PARTICULAR IS FAVORABLE FOR HIGH SNOWFALL RATES ACROSS SOUTHEAST WY.
A BUFKIT TIME-HEIGHT PLOT FROM KCYS SHOWS THE COMBINATION OF
EASTERLY 700MB WINDS AND UPWARD MOTION IN THE DENDRITE GROWTH ZONE
BEING MAXIMIZED BETWEEN 00Z-06Z. SNOWFALL ACROSS THE NE PANHANDLE
WILL LIKELY HOLD OFF UNTIL LATE TONIGHT WHEN THE MIDLEVEL DYNAMICS
ARRIVE.
THE 500MB LOW WILL BEGIN ITS PROGRESSION TO THE NORTHEAST ON
FRIDAY MOVING...MOVING ACROSS EASTERN CO AND NORTHWESTERN KS. THE
HEAVIEST SNOWFALL ON FRIDAY...ESPECIALLY BY AFTN...IS EXPECTED OVER
THE SOUTHERN PART OF THE NEBRASKA PANHANDLE CLOSEST TO THE 700MB
LOW. 700MB FCTS AT 18Z FRI SHOW AN AXIS OF HIGHER NE WINDS (AROUND
35 KTS) STRETCHING ACROSS CHEYENNE COUNTY. BUFKIT SOUNDINGS AT KSNY
AT 18Z SUPPORT GUSTS TO 35 KTS...THUS WILL CONTINUE THE BLIZZARD
WARNING ACROSS CHEYENNE COUNTY. ANY SUBSTANTIAL MIDLEVEL
FRONTOGENESIS IS PROGGED TO BE SOUTH AND EAST OF THE CWA THROUGHOUT
THE ENTIRE EVENT. THUS...NOT EXPECTING OVERLY HIGH SNOWFALL
RATES...HOWEVER THE LONG DURATION OF LOW-LEVEL UPSLOPE WILL PRODUCE
STORM TOTAL SNOWFALL AMOUNTS BETWEEN 7 TO 10 INCHES ALONG INTERSTATE
80 THROUGH FRIDAY NIGHT. EXPECT HIGHER AMOUNTS IN THE
OROGRAPHICALLY FAVORED SOUTH LARAMIE RANGE NEAR THE I-80 SUMMIT.
AMOUNTS WILL DROP OFF TO THE NORTH AND WEST...IN AREAS FURTHER
REMOVED FROM THE MIDLEVEL LOW. SNOW WILL BEGIN TO TAPER OFF FROM
WEST TO EAST OVER THE CWA BY LATE FRIDAY NIGHT AS THE MAIN 500MB LOW
CONTINUES ITS PROGRESSION EASTWARD AND THE SFC HIGH SETTLES OVER
SOUTHEAST WY.
LONG TERM...SATURDAY THROUGH THURSDAY
12Z GFS AND ECMWF 500 MB SYNOPTIC PATTERNS SIMILAR...LEADING TO
MODERATE TO HIGH CONFIDENCE IN THEIR RESPECTIVE MODEL SOLUTIONS.
SATURDAY...SHORTWAVE TROUGH ALOFT WILL BE MOVING OFF TO OUR
EAST...THUS DECREASING SNOW CHANCES ACROSS OUR SOUTHERN COUNTIES.
SUNDAY...SLOW WARMING TREND ON TAP AS HEIGHTS AND THICKNESSES RISE.
DRY WITH LACK OF LOW AND MID LEVEL MOISTURE.
MONDAY...ANOTHER WEAK COLD FRONT MOVES SOUTH ACROSS OUR
COUNTIES...THOUGH THE BULK OF THE COLDER AIR WILL REMAIN NORTH AND
EAST OF OUR AREA. CONTINUED DRY WITH LIMITED LOW AND MID LEVEL
MOISTURE.
TUESDAY-THURSDAY...DRY NORTHWEST FLOW ALOFT WILL PREVAIL. WARMING
TREND WILL CONTINUE AS HEIGHTS AND THICKNESSES RISE.
AVIATION...18Z TAFS
THROUGH 00Z...CIGS AND VISIBILITIES LOWERING
TO IFR IN SNOW AND FOG ACROSS CARBON COUNTY WITH MOUNTAIN
OBSCURATION. VFR ELSEWHERE.
AFTER 00Z...WIDESPREAD IFR AND LIFR DEVELOPING IN SNOW AND FOG
AT RAWLINS...LARAMIE...CHEYENNE AND SIDNEY ALONG WITH MOUNTAIN
OBSCURATION. MVFR DUE TO CLOUDS...SNOW AND FOG DEVELOPING AT
CHADRON...SCOTTSBLUFF AND ALLIANCE.
AFTER 12Z...WIDESPREAD IFR IN SNOW AND FOG...WITH LIFR AND VLIFR AT
TIMES AT LARAMIE...CHEYENNE AND SIDNEY. MOUNTAINS OBSCURED. RUBIN
FIRE WEATHER...NO FIRE WEATHER CONCERNS
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING UNTIL 11 PM FRIDAY FOR WYZ106-WYZ107-WYZ116-
WYZ117-WYZ118-WYZ119.
WINTER WEATHER ADVISORY UNTIL 5 PM FRIDAY FOR WYZ103-WYZ114-
WYZ115.
WINTER WEATHER ADVISORY UNTIL 11 PM FRIDAY FOR WYZ108.
NE...WINTER WEATHER ADVISORY UNTIL 11 PM FRIDAY FOR NEZ003-NEZ019-
NEZ096.
WINTER STORM WARNING UNTIL 11 PM FRIDAY FOR NEZ020-NEZ021-NEZ054.
BLIZZARD WARNING UNTIL 11 PM FRIDAY FOR NEZ055.
&&
$$
UPDATE...HAMMER/LIEBL
SHORT TERM/FIRE WEATHER...FINCH
LONG TERM...RUBIN
AVIATION...LIEBL
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
625 AM EST FRI FEB 3 2012
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS/NEAR TERM /ISSUED AT 408 AM/...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF
DOMINATING THE UPR LKS AROUND VORTEX OVER NRN QUEBEC. DESPITE THIS
NW FLOW...WHICH USUALLY BRINGS SOME INTENSE CHILL TO UPR MI THIS
TIME OF YEAR...THE AIRMASS IS UNSEASONABLY WARM OVER THE AREA. 00Z
H85 TEMPS RANGE FROM 1C AT MPX AND -1C AT GRB TO -5C AT INL AND APX
TO -8C AT YPL. ALTHOUGH THE AIR TO THE N AND NE TOWARD THE VORTEX IS
COLDER...THE 00Z H85 TEMPS AT CHURCHILL MANITOBA AND MOOSONEE ON THE
S SHORE OF JAMES BAY ARE ONLY -14C AND -11C RESPECTIVELY. 00Z RAOBS
INDICATE THESE HI H85 TEMPS ARE ASSOCIATED WITH A SHARP SUBSIDENCE
INVRN...WITH LLVL MSTR TRAPPED BLO THE INVRN BASE RESULTING IN
WDSPRD LO CLD FM THE UPR MIDWEST THRU THE UPR GRT LKS AND INTO
ONTARIO. A FEW BREAKS IN THE ST/SC ARE OVER NW LK SUP. THERE IS A
DISTURBANCE EMBEDDED IN THE NW FLOW ALF PASSING THRU NRN ONTARIO.
ALTHOUGH THIS SHRTWV IS PASSING WELL NE OF THE AREA...SOME RADAR
ECHOES UP TO 15 DBZ HAVE SHOWN UP TO THE NE OVER OVER LK SUP ALONG
ATTENDANT LO PRES TROF AXIS EXTENDING SWWD FM SFC LO NEAR MOOSONEE
INTO ERN LK SUP. SFC HI PRES UNDER 12HR H3 HGT RISES UP TO 110M AT
GRB STRETCHES ESEWD FM NRN MN THRU NE WI INTO LWR MI. THERE IS MORE
CLEARING OVER FAR NW ONTARIO...WHERE DRIER LLVL AIR IS PRESENT.
IN THE NEAR TERM...ALTHOUGH SOME BREAKS IN THE LO CLD MAY IMPACT NW
UPR MI...OVC ST/SC WL BE RULE THRU SUNRISE OVER MOST OF THE AREA.
SINCE THE AIRMASS IS SO WARM...ANY PCPN OVER THE ERN CWA WL BE
NOTHING MORE THAN DZ OR PERHAPS FZDZ INLAND FM THE SHORE/FLURRIES.
THE CLDS WL GREATLY LIMIT THE FALL OF THE THERMOMETER...WITH
READINGS GENERALLY NOT FAR FM 32 AT SUNRISE TO PERHAPS UPR 20S OVER
THE INTERIOR.
&&
.SHORT TERM /TODAY THRU SAT NGT/...
TODAY...HI PRES RDG AXIS TRAILING DISTURBANCE/SFC LO NOW IN NE
ONTARIO WL BRING A DRY DAY TO UPR MI. MAIN FCST CONCERN WL BE IF AND
WHEN LO CLDS OVER THE CWA WL BREAK UP AND THE IMPACT ON TEMPS. BOTH
THE 00Z NAM/LOCAL WRF-ARW RUNS SHOW DRIER H95-9 AIR NOW OVER FAR NW
ONTARIO PUSHING INTO THE CWA...BUT NOT UNTIL LATE IN THE DAY. IN
CONCERT WITH MORE ACYC FLOW...EXPECT THE LO CLDS TO BREAK UP. BUT
THIS SHOULD BE TOO LATE IN THE DAY...ONLY AFT 21Z OR SO...TO HAVE A
SNGFT IMPACT ON TEMPS. WITH TEMPS SO WARM...THE CLD TRENDS MAY BE
SIMILAR TO WHAT HAPPENS HERE IN EARLY SPRING...WITH CLRG OVER LK SUP
FASTER THAN THE LAND. PER UPSTREAM HI TEMPS YDAY AND PERSISTENT CLD
COVER OVER LAND...EXPECT TEMPS TO TOP OUT ON THE LO SIDE OF GUIDANCE
AND IN THE LO TO MID 30S.
TNGT...SFC HI PRES/DRY AIRMASS WL BE DOMINATING. WITH THE RDG AXIS
DIRECTLY OVHD...WINDS WL BE LGT IN THE EVNG. BUT AS ANOTHER
DISTURBANCE DROPS SEWD THRU ONTARIO IN THE NW FLOW ALF...THE W WIND
MAY PICK UP AGAIN...ESPECIALLY NEAR LK SUP. EXPECT THE LOWEST MIN
TEMPS TOWARD THE LO END OF GUIDANCE NEAR THE WI BORDER WITH LIGHTER
WINDS THE WHOLE NGT. ALTHOUGH THE MERCURY MAY DIP INTO THE SINGLE
DIGITS ABV ZERO AT A FEW PLACES...THESE READINGS WL STILL BE WELL
ABV AVG.
SAT...NEXT SHRTWV DROPPING SSEWD IN NW FLOW ALF ARND VORTEX IN
QUEBEC WL BE DIGGING INTO THE UPR LKS. THE 00Z CNDN MODEL IS FARTHER
W WITH THE TRACK OF THIS FEATURE...WHILE THE 00Z NAM/GFS ARE A BIT
FARTHER TO THE E. PER NCEP GUIDANCE...FOLLOWED THE INTERMEDIATE
TRACK OF THE 12Z ECWMF. ALTHOUGH THE AIRMASS WL BE RATHER DRY...
OPTED TO INCLUDE SCHC POPS FOR SHSN OVER THE E ON THE CYC SIDE OF
THE TRACK OF THIS FEATURE...WHERE THE GFS/ECMWF GENERATE SOME LGT
PCPN UNDER SHARPER DPVA/DEEP LYR QVECTOR CNVGC.
SAT NGT...ONCE THE SHRTWV PASSES SAT EVNG...EXPECT SFC HI PRES RDG
TO BUILD BACK INTO THE UPR LKS UNDER RISING HGTS/DNVA/DEEP LYR
QVECTOR DVGC. FCST H85 TEMPS IN THE -4 TO -8C RANGE IN THE WAKE OF
THE SHRTWV WL BE TOO HI FOR LES. WITH SKIES TRENDING MOCLR/
DIMINISHING WINDS AND PWAT FALLING TO 0.15-0.20 INCH OR 75 PCT OF
NORMAL LATE...EXPECT A FAIRLY STEEP DIURNAL FALL OF TEMP TOWARD THE
LO END OF GUIDANCE AWAY FM LK MODERATION.
.LONG TERM...SUNDAY THROUGH THURSDAY
SUN INTO SUN NIGHT...AS THE MID/UPPER LEVEL RIDGE BUILDS FROM THE
NORTHERN PLAINS INTO THE UPPER MS VALLEY...WRLY SFC WINDS WILL
INCREASE BTWN HIGH PRES OVER THE PLAINS AND LOW PRES OVER NE CANADA.
FCST SOUNDINGS SHOW A DRY PROFILE WITH ONLY SOME MID LEVEL MOISTURE
AS THE 925-850 MB THERMAL RIDGE EXTENDS INTO THE NRN GREAT LAKES.
EVEN WITH SOME MID CLOUDS POSSIBLE...EXPECT ENOUGH SUNSHINE TO HELP
BOOST TEMPS WELL ABOVE NORMAL WITH MAX TEMPS IN THE UPPER 30S AND TO
AROUND 40 IN DOWNSLOPE FLOW LOCATIONS. THE WEST WINDS WILL ALSO KEEP
TEMPS FROM FALLING OFF AS FAR WITH MIN TEMPS MAINLY IN THE 20S.
MON THROUGH WED...MODELS WERE IN BETTER AGREEMENT WITH THE SHALLOW
COLD AIR INTRUSION MON NIGHT INTO TUE BEHIND A COLD FRONT. EVEN
THOUGH 925-900 MB TEMPS FALL TO AROUND -17C...INVERSION HEIGHTS AOB
4K FT AND VERY DRY AIR UPSTREAM...WILL NOT BE FAVORABLE FOR
SIGNIFICANT LES. SO....WILL KEEP LOWER END CHANCE POPS FOR NRLY FLOW
LES MON NIGHT INTO TUE. HIGH PRES IS EXPECTED TO BUILD INTO THE
REGION LATE TUE INTO WED...BRINGING AN END TO ANY LES WITH MAINLY
DRY CONDITIONS TUE INTO WED.
THU...THE MODELS HAVE SHOWN CONSIDERABLE VARIATION WITH THE EXTENT
OF COLD AIR MOVING IN ON THE EDGE OF THE POLAR VORTEX DROPPING INTO
ERN CANADA. THE 00Z/03 ECMWF WAS MUCH LESS AGGRESSIVE WITH THE
COLDER AIR COMPARED TO THE 12/02 RUN AND IS CLOSER TO ITS ENS MEAN
AND THE GFS/GFS ENS MEAN...SHOWING 850 MB TEMPS TO AROUND -16C BY
12Z/FRI. THE COLDEST AIR AND BEST CHANCE FOR LES WOULD ARRIVE MAINLY
AFTER THE FCST PERIOD INTO FRI.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
EXPECT MFR CIGS TO LINGER INTO THIS AFTN UNTIL WEDGE OF DRY AIR
ASSOCIATED WITH A HI PRES RDG AXIS MOVES INTO UPR MI FROM THE NW...
BRINGING VFR CONDITIONS BY 00Z SAT. THIS IMPROVEMENT SHOULD PERSIST
THRU THE NGT...BUT UPSLOPE W WIND LATER AT CMX MIGHT CAUSE A RETURN
OF MVFR CIGS THERE.
&&
.MARINE...A SURFACE RIDGE WILL REMAIN IN CONTROL THROUGH EARLY
SUNDAY NIGHT KEEPING WINDS AND WAVES FAIRLY LIGHT. WESTERLY WINDS
ARE EXPECTED TO INCREASE INTO THE 15 TO 25 KT RANGE LATE SUN INTO
SUN NIGHT AS THE RIDGE MOVES TO THE SOUTH TOWARD THE SRN LAKES AND
OHIO VALLEY. THE NEXT CHANCE OF INCREASED WAVE HEIGHT AND WIND GUSTS
WILL BE MONDAY NIGHT INTO TUESDAY AS PRESSURE GRADIENT INCREASES
BETWEEN HIGH PRESSURE OVER SASKATCHEWAN AND LOW PRESSURE OVER
CENTRAL QUEBEC AS A COLD FRONT DROPS SOUTH THROUGH THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLB
AVIATION...KC
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
955 AM CST FRI FEB 3 2012
.UPDATE...
/950 AM CST FRI FEB 3 2012/
12Z 850MB ANALYSIS SHOWS STOUT 35-40KT LLJ PUMPING UNSEASONABLY
HIGH AMOUNTS OF MOISTURE TO THE TUNE OF +10C DEWPOINT INTO THE
MISSOURI. SHROEDER RULE IN EFFECT...WITH MOISTURE CONVERGENCE
BEING MAXIMIZED ALONG THE 850MB WARM FRONT AS IT LIFTS NORTHEAST.
RAIN SHOWERS CONTINUE TO BLOSSOM AND WILL MOVE NORTHEAST
OVERSPREADING THE ENTIRE CWA LATE THIS MORNING AND INTO THE
AFTERNOON. DRY AIR NO MATCH FOR THIS AMOUNT OF FORCING AND
MOISTURE FLUX...WITH QUICK TOP DOWN SATURATION. CLOUDS AND
PRECIPITATION WILL LIMIT DIURNAL TEMPERATURE RISE...SO WILL BE
UNDERCUTTING HIGHS FOR TODAY. UPDATE COMING OUT SOON.
/907 AM CST FRI FEB 3 2012/
HAVE UPDATED FORECAST TO ACCOUNT FOR DEVELOPING WARM ADVECTION
RAIN SHOWERS DEVELOPING ACROSS OZARKS. THIS BATCH OF SHOWERS
SHOULD CONTINUE TO DEVELOP AND MOVE NORTHEAST...REACHING THE ST.
LOUIS METRO AROUND LUNCH TIME.
CVKING
&&
.DISCUSSION...
/310 AM CST FRI FEB 3 2012/
WET WEATHER STILL ON TAP FOR THE NEXT SEVERAL DAYS COURTESY OF THE
UPPER LOW SPINNING NEAR THE CO/NM BORDER. THE MODELS ARE IN PRETTY
DECENT AGREEMENT THROUGH THE FIRST 48H TRACKING THE UPPER LOW
THROUGH THE CENTRAL ROCKIES TODAY AND TO FAR NE KS BY SATURDAY
EVENING. IN RESPONSE THE ASSOCIATED SURFACE LOW WILL TRACK FROM
WESTERN TEXAS INTO SE KS BY DAYBREAK SATURDAY AND TO EXTREME
SOUTHERN IL BY EARLY SATURDAY EVENING.
THE INITIAL FORECAST PROBLEM WITH THIS SYSTEM IS THE TIMING OF THE
ONSET OF PRECIPITATION. THE MAJORITY OF THE LATEST MODEL RUNS HAVE
SLOWED THE EASTWARD DEVELOPMENT TODAY WITH THE NAM SUGGESTING THAT
RAIN WILL ONLY GET INTO CENTRAL MO BEFORE 00Z TONIGHT...WHILE THE
OTHER MODEL GUIDANCE BRINGS IT TO OR JUST EAST OF THE MS RIVER.
WHILE I`M INCLINED TO BELIEVE THIS MORNING WILL BE DRY...I THINK
RAIN WILL REALLY GET GOING THIS AFTERNOON AS LARGE SCALE ASCENT
OVERSPREADS MO AND MOISTURE TRANSPORT ACCELERATES DUE TO THE
INCREASINGLY SOUTHERLY LLJ. THE LAST HRRR RUN ALSO SUPPORTS THIS
NOTION...WITH RAIN MAKING IT TO THE MS RIVER BY 00Z...WHILE LOW
LEVEL DRY HOLDS IT AT BAY UNTIL THIS EVENING OVER MUCH OF IL. RAIN
WILL THEN SPREAD ACROSS IL THIS EVENING IN CONCERT WITH THE
ADVANCING STORM SYSTEM AND EASTWARD SHIFT OF LIFT AND MOISTURE
TRANSPORT. THE GUIDANCE CONTINUES TO SHOW ELEVATED INSTABILITY
SUPPORTING THE POTENTIAL FOR SOME EMBEDDED THUNDERSTORMS WITH
LOCALLY HEAVY RAIN.
DESPITE A RATHER BLOCKY UPPER AIR PATTERN THAT ENSUES ACROSS THE
WESTERN CONUS OVER THE NEXT TWO DAYS...IT APPEARS THAT UPPER LOW
WILL REMAIN PROGRESSIVE GETTING PICKED UP A NORTHERN STREAM UPPER
TROF DIGGING INTO THE EASTERN U.S. ON SATURDAY NIGHT. THIS SHOULD
AT LEAST SHUNT THE DYING UPPER LOW SEWD THROUGH THE AREA SATURDAY
NIGHT INTO SUNDAY. THIS ALLOWS SOME DEEPER COLD AIR TO INFILTRATE
ON SATURDAY NIGHT IN THE WAKE OF THE LOW LEVEL CYCLONE...BUT THE
SNOW POTENTIAL STILL LOOKS IFFY AND AT THIS POINT WILL JUST KEEP
WITH THE CURRENT FORECAST OF A CHANCE OF RAIN OR SNOW.
GLASS
&&
.AVIATION...
/525 AM CST FRI FEB 3 2012/
STORM SYSTEM TAKING SHAPE OVER THE GREAT PLAINS WILL SPREAD WET
WEATHER ACROSS THE AREA THIS AFTERNOON INTO TONIGHT. UNTIL
THEN...VFR FLIGHT CONDITIONS AND EAST-SOUTHEAST FLOW WILL PREVAIL.
RAIN AND WIDELY SCATTERED THUNDERSTORMS WILL OVERSPREAD THE AREA
FROM THE WEST DURING THE MID-LATE AFTERNOON. INITIALLY...DON`T
EXPECT CIGS/VSBYS TO DETERIORATE MUCH EXCEPT IN POCKETS OF HEAVIER
RAIN. BUT BY EARLY EVENING MVFR CIGS WILL SPREAD EAST ACROSS THE
AREA...AND FINALLY IFR DURING THE LATE EVENING AND OVERNIGHT. IFR
WILL LIKELY PERSIST THROUGH MUCH OF THE DAY SATURDAY AS THE STORM
CONTINUES TO IMPACT THE REGION.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS AND EAST-SOUTHEAST FLOW WILL PREVAIL AT
LEAST THROUGH THE AFTERNOON. SOME LIGHT RAIN SHOWERS ARE LIKELY
JUST BEFORE 00Z AS RAIN OVERSPREADS THE REGION FROM THE WEST...BUT
LOWERED CIGS OR VSBYS DO NOT LOOK LIKELY UNTIL MID-LATE THIS
EVENING WHEN HEAVIER SHOWERS MOVE INTO THE AREA. IFR CONDITIONS
LOOK LIKELY TO DEVELOP DURING THE PRE-DAWN HOURS OF SATURDAY
MORNING MORNING AND PERSIST THROUGH SATURDAY.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED
NWS ST LOUIS MO
908 AM CST FRI FEB 3 2012
.UPDATE...
/907 AM CST FRI FEB 3 2012/
HAVE UPDATED FORECAST TO ACCOUNT FOR DEVELOPING WARM ADVECTION
RAIN SHOWERS DEVELOPING ACROSS OZARKS. THIS BATCH OF SHOWERS
SHOULD CONTINUE TO DEVELOP AND MOVE NORTHEAST...REACHING THE ST.
LOUIS METRO AROUND LUNCH TIME.
CVKING
&&
.DISCUSSION...
/310 AM CST FRI FEB 3 2012/
WET WEATHER STILL ON TAP FOR THE NEXT SEVERAL DAYS COURTESY OF THE
UPPER LOW SPINNING NEAR THE CO/NM BORDER. THE MODELS ARE IN PRETTY
DECENT AGREEMENT THROUGH THE FIRST 48H TRACKING THE UPPER LOW
THROUGH THE CENTRAL ROCKIES TODAY AND TO FAR NE KS BY SATURDAY
EVENING. IN RESPONSE THE ASSOCIATED SURFACE LOW WILL TRACK FROM
WESTERN TEXAS INTO SE KS BY DAYBREAK SATURDAY AND TO EXTREME
SOUTHERN IL BY EARLY SATURDAY EVENING.
THE INITIAL FORECAST PROBLEM WITH THIS SYSTEM IS THE TIMING OF THE
ONSET OF PRECIPITATION. THE MAJORITY OF THE LATEST MODEL RUNS HAVE
SLOWED THE EASTWARD DEVELOPMENT TODAY WITH THE NAM SUGGESTING THAT
RAIN WILL ONLY GET INTO CENTRAL MO BEFORE 00Z TONIGHT...WHILE THE
OTHER MODEL GUIDANCE BRINGS IT TO OR JUST EAST OF THE MS RIVER.
WHILE I`M INCLINED TO BELIEVE THIS MORNING WILL BE DRY...I THINK
RAIN WILL REALLY GET GOING THIS AFTERNOON AS LARGE SCALE ASCENT
OVERSPREADS MO AND MOISTURE TRANSPORT ACCELERATES DUE TO THE
INCREASINGLY SOUTHERLY LLJ. THE LAST HRRR RUN ALSO SUPPORTS THIS
NOTION...WITH RAIN MAKING IT TO THE MS RIVER BY 00Z...WHILE LOW
LEVEL DRY HOLDS IT AT BAY UNTIL THIS EVENING OVER MUCH OF IL. RAIN
WILL THEN SPREAD ACROSS IL THIS EVENING IN CONCERT WITH THE
ADVANCING STORM SYSTEM AND EASTWARD SHIFT OF LIFT AND MOISTURE
TRANSPORT. THE GUIDANCE CONTINUES TO SHOW ELEVATED INSTABILITY
SUPPORTING THE POTENTIAL FOR SOME EMBEDDED THUNDERSTORMS WITH
LOCALLY HEAVY RAIN.
DESPITE A RATHER BLOCKY UPPER AIR PATTERN THAT ENSUES ACROSS THE
WESTERN CONUS OVER THE NEXT TWO DAYS...IT APPEARS THAT UPPER LOW
WILL REMAIN PROGRESSIVE GETTING PICKED UP A NORTHERN STREAM UPPER
TROF DIGGING INTO THE EASTERN U.S. ON SATURDAY NIGHT. THIS SHOULD
AT LEAST SHUNT THE DYING UPPER LOW SEWD THROUGH THE AREA SATURDAY
NIGHT INTO SUNDAY. THIS ALLOWS SOME DEEPER COLD AIR TO INFILTRATE
ON SATURDAY NIGHT IN THE WAKE OF THE LOW LEVEL CYCLONE...BUT THE
SNOW POTENTIAL STILL LOOKS IFFY AND AT THIS POINT WILL JUST KEEP
WITH THE CURRENT FORECAST OF A CHANCE OF RAIN OR SNOW.
GLASS
&&
.AVIATION...
/525 AM CST FRI FEB 3 2012/
STORM SYSTEM TAKING SHAPE OVER THE GREAT PLAINS WILL SPREAD WET
WEATHER ACROSS THE AREA THIS AFTERNOON INTO TONIGHT. UNTIL
THEN...VFR FLIGHT CONDITIONS AND EAST-SOUTHEAST FLOW WILL PREVAIL.
RAIN AND WIDELY SCATTERED THUNDERSTORMS WILL OVERSPREAD THE AREA
FROM THE WEST DURING THE MID-LATE AFTERNOON. INITIALLY...DON`T
EXPECT CIGS/VSBYS TO DETERIORATE MUCH EXCEPT IN POCKETS OF HEAVIER
RAIN. BUT BY EARLY EVENING MVFR CIGS WILL SPREAD EAST ACROSS THE
AREA...AND FINALLY IFR DURING THE LATE EVENING AND OVERNIGHT. IFR
WILL LIKELY PERSIST THROUGH MUCH OF THE DAY SATURDAY AS THE STORM
CONTINUES TO IMPACT THE REGION.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS AND EAST-SOUTHEAST FLOW WILL PREVAIL AT
LEAST THROUGH THE AFTERNOON. SOME LIGHT RAIN SHOWERS ARE LIKELY
JUST BEFORE 00Z AS RAIN OVERSPREADS THE REGION FROM THE WEST...BUT
LOWERED CIGS OR VSBYS DO NOT LOOK LIKELY UNTIL MID-LATE THIS
EVENING WHEN HEAVIER SHOWERS MOVE INTO THE AREA. IFR CONDITIONS
LOOK LIKELY TO DEVELOP DURING THE PRE-DAWN HOURS OF SATURDAY
MORNING MORNING AND PERSIST THROUGH SATURDAY.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
558 AM CST FRI FEB 3 2012
.DISCUSSION...
/310 AM CST FRI FEB 3 2012/
WET WEATHER STILL ON TAP FOR THE NEXT SEVERAL DAYS COURTESY OF THE
UPPER LOW SPINNING NEAR THE CO/NM BORDER. THE MODELS ARE IN PRETTY
DECENT AGREEMENT THROUGH THE FIRST 48H TRACKING THE UPPER LOW
THROUGH THE CENTRAL ROCKIES TODAY AND TO FAR NE KS BY SATURDAY
EVENING. IN RESPONSE THE ASSOCIATED SURFACE LOW WILL TRACK FROM
WESTERN TEXAS INTO SE KS BY DAYBREAK SATURDAY AND TO EXTREME
SOUTHERN IL BY EARLY SATURDAY EVENING.
THE INITIAL FORECAST PROBLEM WITH THIS SYSTEM IS THE TIMING OF THE
ONSET OF PRECIPITATION. THE MAJORITY OF THE LATEST MODEL RUNS HAVE
SLOWED THE EASTWARD DEVELOPMENT TODAY WITH THE NAM SUGGESTING THAT
RAIN WILL ONLY GET INTO CENTRAL MO BEFORE 00Z TONIGHT...WHILE THE
OTHER MODEL GUIDANCE BRINGS IT TO OR JUST EAST OF THE MS RIVER.
WHILE I`M INCLINED TO BELIEVE THIS MORNING WILL BE DRY...I THINK
RAIN WILL REALLY GET GOING THIS AFTERNOON AS LARGE SCALE ASCENT
OVERSPREADS MO AND MOISTURE TRANSPORT ACCELERATES DUE TO THE
INCREASINGLY SOUTHERLY LLJ. THE LAST HRRR RUN ALSO SUPPORTS THIS
NOTION...WITH RAIN MAKING IT TO THE MS RIVER BY 00Z...WHILE LOW
LEVEL DRY HOLDS IT AT BAY UNTIL THIS EVENING OVER MUCH OF IL. RAIN
WILL THEN SPREAD ACROSS IL THIS EVENING IN CONCERT WITH THE
ADVANCING STORM SYSTEM AND EASTWARD SHIFT OF LIFT AND MOISTURE
TRANSPORT. THE GUIDANCE CONTINUES TO SHOW ELEVATED INSTABILITY
SUPPORTING THE POTENTIAL FOR SOME EMBEDDED THUNDERSTORMS WITH
LOCALLY HEAVY RAIN.
DESPITE A RATHER BLOCKY UPPER AIR PATTERN THAT ENSUES ACROSS THE
WESTERN CONUS OVER THE NEXT TWO DAYS...IT APPEARS THAT UPPER LOW
WILL REMAIN PROGRESSIVE GETTING PICKED UP A NORTHERN STREAM UPPER
TROF DIGGING INTO THE EASTERN U.S. ON SATURDAY NIGHT. THIS SHOULD
AT LEAST SHUNT THE DYING UPPER LOW SEWD THROUGH THE AREA SATURDAY
NIGHT INTO SUNDAY. THIS ALLOWS SOME DEEPER COLD AIR TO INFILTRATE
ON SATURDAY NIGHT IN THE WAKE OF THE LOW LEVEL CYCLONE...BUT THE
SNOW POTENTIAL STILL LOOKS IFFY AND AT THIS POINT WILL JUST KEEP
WITH THE CURRENT FORECAST OF A CHANCE OF RAIN OR SNOW.
GLASS
&&
.AVIATION...
/525 AM CST FRI FEB 3 2012/
STORM SYSTEM TAKING SHAPE OVER THE GREAT PLAINS WILL SPREAD WET
WEATHER ACROSS THE AREA THIS AFTERNOON INTO TONIGHT. UNTIL
THEN...VFR FLIGHT CONDITIONS AND EAST-SOUTHEAST FLOW WILL PREVAIL.
RAIN AND WIDELY SCATTERED THUNDERSTORMS WILL OVERSPREAD THE AREA
FROM THE WEST DURING THE MID-LATE AFTERNOON. INITIALLY...DON`T
EXPECT CIGS/VSBYS TO DETERIORATE MUCH EXCEPT IN POCKETS OF HEAVIER
RAIN. BUT BY EARLY EVENING MVFR CIGS WILL SPREAD EAST ACROSS THE
AREA...AND FINALLY IFR DURING THE LATE EVENING AND OVERNIGHT. IFR
WILL LIKELY PERSIST THROUGH MUCH OF THE DAY SATURDAY AS THE STORM
CONTINUES TO IMPACT THE REGION.
SPECIFICS FOR KSTL...
VFR FLIGHT CONDITIONS AND EAST-SOUTHEAST FLOW WILL PREVAIL AT
LEAST THROUGH THE AFTERNOON. SOME LIGHT RAIN SHOWERS ARE LIKELY
JUST BEFORE 00Z AS RAIN OVERSPREADS THE REGION FROM THE WEST...BUT
LOWERED CIGS OR VSBYS DO NOT LOOK LIKELY UNTIL MID-LATE THIS
EVENING WHEN HEAVIER SHOWERS MOVE INTO THE AREA. IFR CONDITIONS
LOOK LIKELY TO DEVELOP DURING THE PRE-DAWN HOURS OF SATURDAY
MORNING MORNING AND PERSIST THROUGH SATURDAY.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
911 AM CST FRI FEB 3 2012
.UPDATE...BASED ON INCOMING SNOWFALL REPORTS ACROSS THE CENTRAL
SANDHILLS...EXPANDED THE WINTER STORM WARNING TO ENCOMPASS
THOMAS...AND HOOKER COUNTIES AND ADDED EASTERN CHERRY COUNTY TO THE
WINTER WEATHER ADVISORY. BASED ON RADAR RETURNS AND LOCATION OF THE
DEFORMATION BAND...AND DUE TO THE EARLIER THAN EXPECTED CHANGEOVER
FROM RAIN TO SNOW...WENT AHEAD AND INCREASED ACCUMULATIONS ACROSS THE
NORTHERN PRIPHERY OF THE WARNING FOR MCPHERSON...NORTHERN
LINCOLN...LOGAN...HOOKER...THOMAS...BLAINE COUNTIES.
REAL TIME REPORTS AS WELL AS THE LATEST FORECAST STATEMENTS AND
INFORMATION ON THE STORM CAN BE ACCESSED AT THE FOLLOWING WEB SITE:
WWW.WEATHER.GOV/NORTHPLATTE
&&
PREVIOUS DISCUSSION FOLLOWS...ISSUED AT 326 AM CST FRI FEB 3 2012
.SHORT TERM...THIS HAS BEEN A CHALLENGING FORECAST THE LAST
COUPLE OF NIGHTS...AND UNFORTUNATELY THE IMPENDING WINTER STORM
CONTINUES TO BE HANDLED RATHER POORLY BY THE DETERMINISTIC MODEL
SOLUTIONS. MODELS CONTINUE TO WOBBLE NORTH AND SOUTH WITH THE AREA
OF POTENTIAL HEAVY SNOW. THIS IS LIKELY DUE TO CONVECTION/TSTMS
ACROSS THE SOUTHERN PLAINS CAUSING OVERALL MASS FIELD CHANGES FROM
MODEL RUN TO MODEL RUN. FEEL THAT ANY ONE PARTICULAR DETERMINISTIC
MODEL SOLUTION IS NOT WORTHY OF BASING A FORECAST ON DUE TO THIS
VARIABILITY. WILL SIDE TOWARD MORE OF AN ENSEMBLE/SREF BASED
APPROACH TO MAKING ANY FORECAST CHANGES THIS MORNING...AND USE THE
DETERMINISTIC MODELS MORE OR LESS AS GUIDANCE. DID APPEAR THAT THE
00Z NAM INITIALIZED A BIT BETTER THAN THE 00Z GFS BASED OFF WATER
VAPOR AND TROPOSPHERIC HEIGHTS. 00Z NAM SHOWS A NICE TROP FOLD
OVER WESTERN KS BY THIS EVENING...AND THIS IS WHEN THE DEEPENING
OF THE H7 LOW BEGINS. ALL MODELS INDICATE THIS PROCESS...BUT
DETERMINISTIC SOLUTIONS ARE DIFFERING ON EXACTLY WHERE THIS
DEEPENING AND SUBSEQUENT DEFORMATION BAND SET UP. CURRENT RUN OF
THE HRRR SUGGEST THE FIRST HINTS OF THE DEFORMATION BAND FORMING
FROM THE MCCOOK TO NORTH PLATTE AREA BY THE MIDDLE OF THIS
AFTERNOON...AND THAT GIVES SOMEWHAT OF A CONFIDENCE BOOST TO THE
GOING FORECAST. GIVEN THE MODEL VARIABILITY...FEEL THE BEST PLAN
IS TO LET THE CURRENT WARNINGS AND ADVISORIES CONTINUE AS
ARE...AND ONLY MAKE MINOR CHANGES TO THE CURRENT FORECAST. NORTH
WINDS DO INCREASE SOME THIS AFTERNOON...WITH GUSTS UP TO 30 MPH
EXPECTED BY THIS EVENING AS THE SFC LOW DEEPENS IN KS. THIS WILL
CAUSE SOME AREAS OF BLOWING SNOW AND REDUCED VISIBILITY. TOTAL
SNOWFALL ACCUMULATIONS BY SATURDAY NIGHT ARE EXPECTED TO RANGE
FROM 6 TO 11 INCHES ALONG AND SOUTHEAST OF AN ERICSON TO STAPLETON
TO BIG SPRINGS LINE. AMOUNTS GRADUALLY TAPER NORTHWEST OF THIS
LINE...WITH ONLY AN INCH OR SO EXPECTED AT THE NEBRASKA SOUTH
DAKOTA STATE LINE.
.LONG TERM...12Z MONDAY THROUGH THURSDAY. NO MAJOR CHANGES TO THE
LONG TERM FORECAST. THE PROGRESSION AND OVERALL PERFORMANCE OF THE
UPPER LOW WILL HEAVILY DICTATE THE EXTENDED PERIOD...ESPECIALLY
SUNDAY AND MONDAY. WITH THE POTENTIAL OF SIGNIFICANT SNOW
ACCUMULATIONS ACROSS SOUTHWEST THROUGH SOUTH CENTRAL
NEBRASKA...GENERALLY KEPT LATEST HIGHS GOING...AND LOWERED MINS A
FEW DEGREES ACROSS THE EAST. TEMPERATURES TO REACH NEAR 35 ACROSS
THE SNOWPACK SOUTHWEST TO SOUTH CENTRAL NEBRASKA...WITH THE
POTENTIAL OF LOWER 40S ACROSS NORTHERN NEBRASKA WHERE LIGHT AMOUNTS
ARE EXPECTED. ATTENTION THEN TURNS TO A COLD FRONT AND ASSOCIATED
SHORTWAVE THAT WILL DROP SOUTH THROUGH THE NORTHERN HIGH PLAINS LATE
MONDAY NIGHT INTO TUESDAY. BESIDES COOLER TEMPERATURES WITH HIGHS
ONLY IN THE UPPER 20S TO LOWER 30S...THE LONG RANGE MODELS...MOST
NOTABLY THE GFS...DO GENERATE SPOTTY QPF AS THE WAVE EJECTS EAST.
MOST SHOULD BE FOCUSED NEAR THE FRONT RANGE OF WYOMING AND
COLORADO...BUT INTO THE ADJACENT PLAINS...INCLUDING SOUTHWEST
NEBRASKA...WHERE A SLIGHT CHANCE FOR LIGHT SNOW INTRODUCED TUESDAY.
REMAINDER OF EXTENDED CURRENTLY DRY...ALTHOUGH THE ECMWF DOES DROP
ANOTHER DISTURBANCE THROUGH THE CENTRAL HIGH PLAINS LATE WEDNESDAY
AND THURSDAY INCLUDING WESTERN NEBRASKA. THIS NOT SUPPORTED BY THE
GFS. TEMPERATURES SHOULD MODERATE TO THE MID 30S TO NEAR 40S
WEDNESDAY AND THE UPPER 30S/LOWERS 30S BY THURSDAY. IT SHOULD BE
NOTED THAT THE ARCTIC AIR WILL REMAIN WELL TO OUR NORTHEAST ACROSS
THE NORTHERN GREAT LAKES THURSDAY...AS UPPER RIDGING BECOMES
ESTABLISHED ACROSS THE WESTERN CONUS AND NORTHWESTERLY FLOW PREVAILS
ACROSS THE CENTRAL PLAINS.
&&
.AVIATION...DETERIORATING FLIGHT CONDITIONS FOR KLBF AS A STORM
SYSTEM EJECTS FROM THE SOUTH CENTRAL ROCKIES TOWARDS THE CENTRAL
PLAINS. EXPECT CURRENT OVC035 -RA AT KLBF...WITH RAIN MIXING WITH
SNOW BY 15Z...THEN -SN BY 18Z WITH IFR CEILINGS. ACROSS FAR
SOUTHWEST NEBRASKA /KIML...KOGA TERMINALS/ CHANGE OVER TO SNOW
SHOULD OCCUR BETWEEN 12Z-14Z. MODEL GUIDANCE CONTINUES TO INDICATE
THE POTENTIAL FOR BLOWING SNOW FROM SOUTHWEST NEBRASKA THROUGH
SOUTH CENTRAL NEBRASKA BY THIS AFTERNOON AS THE CHANGE OVER FROM
RAIN TO SNOW OCCURS. NORTHERLY WIND GUSTS EXCEEDING 20KTS WILL BE
POSSIBLE...WITH VISIBILITY VALUES POSSIBLY LOWERING BELOW 1SM AT
TIMES THROUGH TONIGHT AT LBF. FURTHER SOUTH AND WEST... VISIBILITY
BELOW A QUARTER MILE MAY BE POSSIBLE. ACROSS THE NORTHERN SAND
HILLS INCLUDING THE KVTN TERMINAL...MODEL SOLUTIONS SUGGEST THE
TREND OF THE SYSTEM HAS BEEN SOUTH...SO WILL ONLY A TEMPO FOR -SN
FROM 22Z-02Z/04TH. AT THIS TIME NOT EXPECTING SIGNIFICANT FLIGHT
DISRUPTIONS...WITH MVFR CEILINGS TO PREVAIL AFTER 20Z.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...BLIZZARD WARNING UNTIL 5 PM MST
SATURDAY FOR NEZ056>058-069.
WINTER STORM WARNING UNTIL 6 PM CST /5 PM MST/ SATURDAY FOR
NEZ022-024>029-035>038-059-070-071.
WINTER WEATHER ADVISORY UNTIL 6 PM CST /5 PM MST/ SATURDAY FOR
NEZ005-008>010-023.
&&
$$
SHORT TERM...TAYLOR
LONG TERM...ROBERG
AVIATION...ROBERG
UPDATE...BUTTLER
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
532 AM CST FRI FEB 3 2012
.SHORT TERM...TODAY THROUGH MONDAY
247 AM CST FRI FEB 3 2012
THE MAIN FOCUS IN THE SHORT TERM IS WITH THE CLOUD COVER AND DENSE
FOG AND WHEN THEY MAY CLEAR OUT.
CURRENTLY...A CLOSED MID LEVEL LOW IS PROPAGATING THROUGH THE
EASTERN ROCKIES WITH A RIDGE AXIS OUT AHEAD OF IT RUNNING ALONG
THE MISSISSIPPI RIVER. AT THE SURFACE...AN ELONGATED RIDGE OF HIGH
PRESSURE STRETCHES FROM THE MID ATLANTIC STATES NORTHWEST THROUGH
THE GREAT LAKES ON INTO THE NORTHERN PLAINS WHILE A LOW STARTS TO
TAKE SHAPE OVER WESTERN TEXAS. A WIDESPREAD BANK OF LOW LEVEL
STRATUS AND FOG ARE IN PLACE FROM THE DAKOTAS INTO THE GREAT LAKES
DUE TO MOISTURE STUCK UNDER A STEEP LOW LEVEL INVERSION. THIS
INVERSION INCREASES IN ITS BASE AS YOU GO TO THE NORTHEAST WITH
THE 03.00Z DVN SOUNDING SHOWING THE INVERSION STARTING AT THE
GROUND...WHERE 1/4SM VISIBILITY WAS BEING REPORTED...WHILE THE
03.00Z GRB SOUNDING WAS A LITTLE OFF THE DECK STARTING AT
900MB...WHERE VISIBILITY WAS P6SM WITH AN OVERCAST STRATUS DECK
AROUND 1KFT.
VISIBILITIES HAVE BEEN THE LOWEST ALONG THE WESTERN FRINGE OF THE
SURFACE RIDGE AXIS WHERE WINDS ARE LIGHT AND THE LOW LEVEL
MOISTURE IS TRAPPED UNDER THIS SHALLOW INVERSION. 03.00Z NAM/GFS
AND 03.06Z RUC SOUNDINGS SHOW THIS INVERSION AND LOW LEVEL
MOISTURE HOLDING ON THROUGH MUCH OF THE DAY BEFORE TRYING TO MIX
OUT THIS LAYER THIS AFTERNOON. CONFIDENCE IN THIS MIXING OUT
OCCURRING IS FAIRLY LOW GIVEN THE MODELS RECENT TRACK RECORD IN
TRYING TO CLEAR THE SKIES OUT. THAT SAID...WINDS DO PICK UP A BIT
OUT OF THE NORTHEAST AS THE LOW PRESSURE SYSTEM STRENGTHENS TO THE
SOUTH WHICH COULD HELP WITH THE MIXING. THUS...FOR NOW HAVE LEFT
THE DENSE FOG ADVISORY GOING UNTIL 18Z TODAY...BUT HAVE CHOPPED
OFF A FEW TIERS OF COUNTIES ACROSS CENTRAL WISCONSIN WHICH HAVE
NOT HAD ANY VISIBILITY ISSUES AND DO NOT APPEAR LIKELY TO DROP
THROUGH THE MORNING.
HOW FAST THE CLOUDS CLEAR OUT WILL PLAY A HUGE ROLE IN TEMPERATURES
THROUGH THE WEEKEND. WHERE SKIES CLEARED OUT ON
THURSDAY...TEMPERATURES SPIKED UP INTO THE 40S AND BROKE A RECORD AT
ROCHESTER. EVEN IF THE LOW LEVEL CLOUDS SCOUR OUT TODAY...THERE
SHOULD STILL BE AMPLE HIGH LEVEL CLOUD COVER IN PLACE DUE TO THE
STORM SYSTEM TO THE SOUTH. WITH CLOUDS POSSIBLY HOLDING ON LONGER
THAN FORECAST...HAVE GONE A BIT PESSIMISTIC ON TEMPERATURES OVER THE
NEXT FEW DAYS.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY
247 AM CST FRI FEB 3 2012
A COLD FRONT DROPS DOWN THROUGH THE REGION MONDAY NIGHT BUT THERE
IS NOT MUCH FORCING OR MOISTURE WITH ITS PASSAGE...SO IT SHOULD
COME THROUGH DRY. WHILE TEMPERATURES WILL DROP BEHIND THE
FRONT...THE MAIN POCKET OF COLD AIR WITH 850MB TEMPERATURES OF
AROUND -20C WILL TRACK OFF TO THE EAST TOWARD NEW ENGLAND. BEYOND
THIS...THE ONLY CHANCE FOR ANY SNOW WILL BE ON WEDNESDAY AS THE
REMNANTS OF A CUT OFF MID LEVEL LOW GET PICKED UP BY THE UPPER
LEVEL FLOW. THE 03.00Z ECMWF IS DEEPER WITH THIS LOW COMPARED TO
THE 03.00Z GFS WHICH JUST BRINGS AN OPEN WAVE THROUGH THE REGION.
REGARDLESS...THIS JUST LEAVES FOR A SLIGHT CHANCE OF SNOW ACROSS
THE FAR SOUTHERN PORTION OF THE FORECAST AREA BUT BEARS WATCHING.
&&
.AVIATION...TODAY AND TONIGHT
532 AM CST FRI FEB 3 2012
LIFR CONDITIONS WILL PERSIST AT KRST THROUGH MID MORNING...AS
ABUNDANT LOW LEVEL MOISTURE AND LIGHT WINDS REMAIN ACROSS THE
AREA. PLAN ON AREAS OF FOG REDUCING VISIBILITIES TO AROUND A
QUARTER MILE...AND CEILINGS AROUND 100 FT. A SLIGHT IMPROVEMENT IS
EXPECTED TODAY AT KRST AT 19Z WITH CEILINGS INCREASING TO 600 FT
AND VISIBILITIES IMPROVING TO AROUND 4SM. AT KLSE...PLAN ON
MVFR/IFR CONDITIONS...WITH CEILINGS IN THE 900 TO 1000 FT RANGE
AND VISIBILITIES AROUND 5 SM IN BR. THESE CONDITIONS WILL LIKELY
PERSIST INTO TONIGHT. A RETURN TO LIFR CONDITIONS CAN BE EXPECTED
AT KRST AROUND 03Z THIS EVENING AS SURFACE TEMPERATURES COOL. LOOK
FOR NORTHEAST WINDS AT 4 TO 8 KTS THROUGH THE FORECAST PERIOD. A
LOW PRESSURE SYSTEM MOVING INTO THE MID MISSISSIPPI RIVER VALLEY
WILL SPREAD HIGH CLOUDS ACROSS THE REGION. A SURFACE RIDGE IS
EXPECTED TO REMAIN IN PLACE ACROSS THE AREA AS THE LOW TRACKS
SOUTH OF THE REGION. THE RIDGE WILL KEEP LIGHT WINDS AND LOW LEVEL
MOISTURE IN PLACE ACROSS THE UPPER MISSISSIPPI RIVER VALLEY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
247 AM CST FRI FEB 3 2012
WI...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR WIZ032-033-041-
053>055-061.
MN...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR MNZ079-086>088-
094>096.
IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...WETENKAMP
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1251 PM EST FRI FEB 3 2012
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS/NEAR TERM /ISSUED AT 408 AM/...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF
DOMINATING THE UPR LKS AROUND VORTEX OVER NRN QUEBEC. DESPITE THIS
NW FLOW...WHICH USUALLY BRINGS SOME INTENSE CHILL TO UPR MI THIS
TIME OF YEAR...THE AIRMASS IS UNSEASONABLY WARM OVER THE AREA. 00Z
H85 TEMPS RANGE FROM 1C AT MPX AND -1C AT GRB TO -5C AT INL AND APX
TO -8C AT YPL. ALTHOUGH THE AIR TO THE N AND NE TOWARD THE VORTEX IS
COLDER...THE 00Z H85 TEMPS AT CHURCHILL MANITOBA AND MOOSONEE ON THE
S SHORE OF JAMES BAY ARE ONLY -14C AND -11C RESPECTIVELY. 00Z RAOBS
INDICATE THESE HI H85 TEMPS ARE ASSOCIATED WITH A SHARP SUBSIDENCE
INVRN...WITH LLVL MSTR TRAPPED BLO THE INVRN BASE RESULTING IN
WDSPRD LO CLD FM THE UPR MIDWEST THRU THE UPR GRT LKS AND INTO
ONTARIO. A FEW BREAKS IN THE ST/SC ARE OVER NW LK SUP. THERE IS A
DISTURBANCE EMBEDDED IN THE NW FLOW ALF PASSING THRU NRN ONTARIO.
ALTHOUGH THIS SHRTWV IS PASSING WELL NE OF THE AREA...SOME RADAR
ECHOES UP TO 15 DBZ HAVE SHOWN UP TO THE NE OVER OVER LK SUP ALONG
ATTENDANT LO PRES TROF AXIS EXTENDING SWWD FM SFC LO NEAR MOOSONEE
INTO ERN LK SUP. SFC HI PRES UNDER 12HR H3 HGT RISES UP TO 110M AT
GRB STRETCHES ESEWD FM NRN MN THRU NE WI INTO LWR MI. THERE IS MORE
CLEARING OVER FAR NW ONTARIO...WHERE DRIER LLVL AIR IS PRESENT.
IN THE NEAR TERM...ALTHOUGH SOME BREAKS IN THE LO CLD MAY IMPACT NW
UPR MI...OVC ST/SC WL BE RULE THRU SUNRISE OVER MOST OF THE AREA.
SINCE THE AIRMASS IS SO WARM...ANY PCPN OVER THE ERN CWA WL BE
NOTHING MORE THAN DZ OR PERHAPS FZDZ INLAND FM THE SHORE/FLURRIES.
THE CLDS WL GREATLY LIMIT THE FALL OF THE THERMOMETER...WITH
READINGS GENERALLY NOT FAR FM 32 AT SUNRISE TO PERHAPS UPR 20S OVER
THE INTERIOR.
&&
.SHORT TERM /TODAY THRU SAT NGT/...
TODAY...HI PRES RDG AXIS TRAILING DISTURBANCE/SFC LO NOW IN NE
ONTARIO WL BRING A DRY DAY TO UPR MI. MAIN FCST CONCERN WL BE IF AND
WHEN LO CLDS OVER THE CWA WL BREAK UP AND THE IMPACT ON TEMPS. BOTH
THE 00Z NAM/LOCAL WRF-ARW RUNS SHOW DRIER H95-9 AIR NOW OVER FAR NW
ONTARIO PUSHING INTO THE CWA...BUT NOT UNTIL LATE IN THE DAY. IN
CONCERT WITH MORE ACYC FLOW...EXPECT THE LO CLDS TO BREAK UP. BUT
THIS SHOULD BE TOO LATE IN THE DAY...ONLY AFT 21Z OR SO...TO HAVE A
SNGFT IMPACT ON TEMPS. WITH TEMPS SO WARM...THE CLD TRENDS MAY BE
SIMILAR TO WHAT HAPPENS HERE IN EARLY SPRING...WITH CLRG OVER LK SUP
FASTER THAN THE LAND. PER UPSTREAM HI TEMPS YDAY AND PERSISTENT CLD
COVER OVER LAND...EXPECT TEMPS TO TOP OUT ON THE LO SIDE OF GUIDANCE
AND IN THE LO TO MID 30S.
TNGT...SFC HI PRES/DRY AIRMASS WL BE DOMINATING. WITH THE RDG AXIS
DIRECTLY OVHD...WINDS WL BE LGT IN THE EVNG. BUT AS ANOTHER
DISTURBANCE DROPS SEWD THRU ONTARIO IN THE NW FLOW ALF...THE W WIND
MAY PICK UP AGAIN...ESPECIALLY NEAR LK SUP. EXPECT THE LOWEST MIN
TEMPS TOWARD THE LO END OF GUIDANCE NEAR THE WI BORDER WITH LIGHTER
WINDS THE WHOLE NGT. ALTHOUGH THE MERCURY MAY DIP INTO THE SINGLE
DIGITS ABV ZERO AT A FEW PLACES...THESE READINGS WL STILL BE WELL
ABV AVG.
SAT...NEXT SHRTWV DROPPING SSEWD IN NW FLOW ALF ARND VORTEX IN
QUEBEC WL BE DIGGING INTO THE UPR LKS. THE 00Z CNDN MODEL IS FARTHER
W WITH THE TRACK OF THIS FEATURE...WHILE THE 00Z NAM/GFS ARE A BIT
FARTHER TO THE E. PER NCEP GUIDANCE...FOLLOWED THE INTERMEDIATE
TRACK OF THE 12Z ECWMF. ALTHOUGH THE AIRMASS WL BE RATHER DRY...
OPTED TO INCLUDE SCHC POPS FOR SHSN OVER THE E ON THE CYC SIDE OF
THE TRACK OF THIS FEATURE...WHERE THE GFS/ECMWF GENERATE SOME LGT
PCPN UNDER SHARPER DPVA/DEEP LYR QVECTOR CNVGC.
SAT NGT...ONCE THE SHRTWV PASSES SAT EVNG...EXPECT SFC HI PRES RDG
TO BUILD BACK INTO THE UPR LKS UNDER RISING HGTS/DNVA/DEEP LYR
QVECTOR DVGC. FCST H85 TEMPS IN THE -4 TO -8C RANGE IN THE WAKE OF
THE SHRTWV WL BE TOO HI FOR LES. WITH SKIES TRENDING MOCLR/
DIMINISHING WINDS AND PWAT FALLING TO 0.15-0.20 INCH OR 75 PCT OF
NORMAL LATE...EXPECT A FAIRLY STEEP DIURNAL FALL OF TEMP TOWARD THE
LO END OF GUIDANCE AWAY FM LK MODERATION.
.LONG TERM...SUNDAY THROUGH THURSDAY
SUN INTO SUN NIGHT...AS THE MID/UPPER LEVEL RIDGE BUILDS FROM THE
NORTHERN PLAINS INTO THE UPPER MS VALLEY...WRLY SFC WINDS WILL
INCREASE BTWN HIGH PRES OVER THE PLAINS AND LOW PRES OVER NE CANADA.
FCST SOUNDINGS SHOW A DRY PROFILE WITH ONLY SOME MID LEVEL MOISTURE
AS THE 925-850 MB THERMAL RIDGE EXTENDS INTO THE NRN GREAT LAKES.
EVEN WITH SOME MID CLOUDS POSSIBLE...EXPECT ENOUGH SUNSHINE TO HELP
BOOST TEMPS WELL ABOVE NORMAL WITH MAX TEMPS IN THE UPPER 30S AND TO
AROUND 40 IN DOWNSLOPE FLOW LOCATIONS. THE WEST WINDS WILL ALSO KEEP
TEMPS FROM FALLING OFF AS FAR WITH MIN TEMPS MAINLY IN THE 20S.
MON THROUGH WED...MODELS WERE IN BETTER AGREEMENT WITH THE SHALLOW
COLD AIR INTRUSION MON NIGHT INTO TUE BEHIND A COLD FRONT. EVEN
THOUGH 925-900 MB TEMPS FALL TO AROUND -17C...INVERSION HEIGHTS AOB
4K FT AND VERY DRY AIR UPSTREAM...WILL NOT BE FAVORABLE FOR
SIGNIFICANT LES. SO....WILL KEEP LOWER END CHANCE POPS FOR NRLY FLOW
LES MON NIGHT INTO TUE. HIGH PRES IS EXPECTED TO BUILD INTO THE
REGION LATE TUE INTO WED...BRINGING AN END TO ANY LES WITH MAINLY
DRY CONDITIONS TUE INTO WED.
THU...THE MODELS HAVE SHOWN CONSIDERABLE VARIATION WITH THE EXTENT
OF COLD AIR MOVING IN ON THE EDGE OF THE POLAR VORTEX DROPPING INTO
ERN CANADA. THE 00Z/03 ECMWF WAS MUCH LESS AGGRESSIVE WITH THE
COLDER AIR COMPARED TO THE 12/02 RUN AND IS CLOSER TO ITS ENS MEAN
AND THE GFS/GFS ENS MEAN...SHOWING 850 MB TEMPS TO AROUND -16C BY
12Z/FRI. THE COLDEST AIR AND BEST CHANCE FOR LES WOULD ARRIVE MAINLY
AFTER THE FCST PERIOD INTO FRI.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
EXPECT MVFR TO LOW END VFR CIGS TO LINGER EARLY THIS AFTERNOON UNTIL
WEDGE OF DRY AIR ASSOCIATED WITH A HIGH PRESSURE RIDGE AXIS MOVES
INTO UPPER MI FROM THE NW. THERE IS POTENTIAL FOR SOME FOG AT ALL
SITES TONIGHT...BUT ENOUGH UNCERTAINTY EXISTS TO KEEP VIS AT 3SM FOR
NOW.
&&
.MARINE...A SURFACE RIDGE WILL REMAIN IN CONTROL THROUGH EARLY
SUNDAY NIGHT KEEPING WINDS AND WAVES FAIRLY LIGHT. WESTERLY WINDS
ARE EXPECTED TO INCREASE INTO THE 15 TO 25 KT RANGE LATE SUN INTO
SUN NIGHT AS THE RIDGE MOVES TO THE SOUTH TOWARD THE SRN LAKES AND
OHIO VALLEY. THE NEXT CHANCE OF INCREASED WAVE HEIGHT AND WIND GUSTS
WILL BE MONDAY NIGHT INTO TUESDAY AS PRESSURE GRADIENT INCREASES
BETWEEN HIGH PRESSURE OVER SASKATCHEWAN AND LOW PRESSURE OVER
CENTRAL QUEBEC AS A COLD FRONT DROPS SOUTH THROUGH THE REGION.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLB
AVIATION...TITUS
MARINE...JLB
AREA FORECAST DISCUSSION...UPDATED
NWS JACKSON MS
1034 AM CST FRI FEB 3 2012
.UPDATE...WIDESPREAD SWATH OF MOSTLY RAIN CONTINUES ACROSS THE REGION
THIS MORNING. THIS HAS BROUGHT ROUGHLY 1.5-3 INCHES OF RAIN TO
PORTIONS OF THE REGION...PARTICULARLY THE SOUTHWEST AND WEST WHERE
SOME OF THE HEAVIER BANDS HAVE TRAINED. SOME STRONGER CONVECTION IS
MOVING INTO THIS SAME AREA WITH ISOLATED THUNDERSTORMS. THIS AREA OF
RAIN IS SLOWLY MOVING NORTHWARD BUT ADDITIONAL SHOWERS CONTINUE TO
MOVE INTO AREAS WHERE THE BULK OF THE RAIN HAS EXITED. THE AIRMASS IS
DEFINITELY MOIST WITH 320-323K THETA-E AIR OVER THE REGION AND AS
INDICATED PER THE 12Z KJAN SOUNDING WITH PW VALUES OF 1.46 INCHES.
CLOUD COVER WILL LIKELY INHIBIT MUCH INSOLATION TODAY...BUT WITH WAA
OCCURRING...WE SHOULD STILL REACH INTO THE 60S AND 70S. HOWEVER WITH
SUCH WIDESPREAD RAIN AND CLOUDS...WE MAY NOT WARM AS MUCH AS FORECAST
AND HAVE DROPPED HIGHS A FEW DEGREES THIS AFTERNOON..WHICH MAY NOT
EVEN BE ENOUGH IN SOME AREAS FURTHER TO THE NORTH. THERE IS STILL SOME
POTENTIAL FOR AN ISOLATED STRONG TO SEVERE STORMS...MAINLY IN THE
SOUTHWESTERN AREAS THIS AFTERNOON WITH THE MAIN POTENTIAL BEING WIND
GUSTS WITH A TORNADO POTENTIAL BEING A LESSER BUT NON-ZERO THREAT
GIVEN 0-1KM HELICITY VALUES EXCEEDING 150-200 M2/S2 PER RUC ANALYSIS.
SEEMS THE BETTER POTENTIAL FOR SVR STORMS WOULD BE IN THE SOUTHWEST
WHERE THE LIFTING WARM FRONT HAS MADE BETTER HEADWAY THAN POINTS
FURTHER NORTH. WILL MAKE SOME ADJUSTMENTS TO THE HWO TO BETTER OUR
THINKING FOR TODAY. /28/
&&
.AVIATION...LOTS OF RAIN ACROSS THE FORECAST AREA THIS MORNING HAS
THUS FAR NOT TRIGGERED A WHOLE LOT OF CEILINGS BELOW 3
KFT...ALTHOUGH VISIBILITIES HAVE BEEN IN THE MVFR RANGE AT TIMES
PURELY BECAUSE OF RAINFALL RATES. ANTICIPATE CEILINGS TO COME DOWN
TO MVFR LEVELS IN MOST AREAS THROUGH THE DAY GRADUALLY AS A WARM
FRONT LIFTS NORTH OF THE REGION AND ALLOWS BETTER LOW LEVEL MOISTURE
TO FEED IN FROM THE SOUTH. EXPECTING WIDESPREAD RA TO GENERALLY
BECOME CONFINED TO AREAS NORTH OF I-20 BY THIS AFTERNOON WITH
SHOWERS AND STORMS BECOMING MORE HIT AND MISS ALONG AND SOUTH OF
I-20. WINDS WILL MAINLY REMAIN LESS THAN 10 KTS...BUT WILL VEER FROM
EAST TO SOUTH THROUGH THE DAY AT MOST SITES AS THE WARM FRONT LIFTS
THROUGH. FOR TONIGHT EXPECT FAR LESS RAIN AROUND THAN THIS PAST
NIGHT BUT LOW CLOUDS AND SOME FOG WILL BE AN ISSUE...THEREFORE
FLIGHT CATS WILL BE BELOW VFR IN MOST CASES. /BB/
&&
.PREV DISCUSSION... /ISSUED 355 AM CST FRI FEB 3 2012/
SHORT TERM...TODAY THROUGH SATURDAY NIGHT...NUMEROUS TO WIDESPREAD
SHOWERS AND EMBEDDED THUNDERSTORMS WITH A FEW POTENTIALLY STRONG TO
SEVERE EXPECTED TODAY AND SATURDAY. DRIER CONDITIONS AND MORE
SEASONABLE TEMPERATURES EXPECTED FOR THE FIRST PART OF THE WORK WEEK
AFTER THE COLD FRONTAL PASSAGE.
CURRENTLY...REGIONAL RADARS SHOWING BROAD AREA OF SHOWERS AND
EMBEDDED THUNDERSTORMS OVER LA AND SW MS...MOVING NNE ALONG THE MS
RIVER WITH SOME LIGHTER SHOWERS NOTED FARTHER EAST ENTERING THE
HWY-98/84 CORRIDOR. THIS CONVECTIVE COMPLEX WILL CONTINUE TO MIGRATE
NNE ALONG THE MS RIVER THROUGH THE MORNING HOURS IN ASSOCIATION WITH
A S/WV ANALYZED BY GFS/NAM. SOME LOCATIONS ACROSS NE LA/SE AR AND NE
MS DELTA REGIONS COULD RECEIVE 2-3 INCH TOTALS THROUGH MIDNIGHT
TONIGHT WITH CURRENT SHOWER ACTIVITY AND ADDITIONAL DEVELOPMENT THIS
AFTERNOON.
DEVELOPMENT OF MORE VIGOROUS THUNDERSTORMS SHOULD OCCUR THIS
AFTERNOON ACROSS WESTERN AREAS AS NAM/GFS CONTINUE TO INDICATE
700-1500 J/KG MUCAPE VALUES IN PRESENCE OF MODEST ISENTROPIC
UPGLIDE AND S/WV MESOSCALE LIFT. A FEW STRONG TO SEVERE TSTORMS
APPEAR POSSIBLE ALONG AND WEST OF A BROOKHAVEN TO GREENVILLE
MISSISSIPPI LINE WITH MAIN HAZARDS OF 60 MPH WIND GUSTS AND QUARTER
HAIL. OF NOTE...BUFR SOUNDINGS PICKING UP ON CURRENT DEWPOINTS
RUNNING A BIT LOW AND INDICATING 900-1400 J/KG SBCAPE ACROSS NE
LA/SW MS THIS AFTERNOON. THESE VALUES WILL BE IN SPATIAL PROXIMITY
TO 0-1 KM SRH VALUES 140-220 M2/S2 ALONG THE LIFTING WARM
FRONT...POTENTIALLY INCREASING THE STILL MARGINAL TORNADO RISK.
LATEST SPC WRF OUTPUT DOES INDICATE SOME WEAK ROTATING UPDRAFTS
ACROSS THE AFOREMENTIONED AREAS AND RUC/NAM EVOLUTION WILL NEED TO
BE MONITORED IN FUTURE UPDATES. WILL LEAVE OUT TORNADO WORDING OF
HWO FOR NOW GIVEN LOW CONFIDENCE IN MARGINAL ENVIRONMENT. TSTORMS
WILL WEAKEN THROUGH THE EVENING AS INSTABILITY DECREASES AND OVERALL
LIFT SUBSIDES.
AS THE S/WV PULLS OUT OF REGION TONIGHT AND EARLY SATURDAY...A LULL
IN PRECIP COVERAGE AND INTENSITY LOOKS LIKELY GOING INTO SATURDAY
MORNING ALONG AND SOUTH OF THE TRACE. THE LULL IS FURTHER SUPPORTED
BY SIMULATED REFLECTIVITY OUTPUT FROM NMM/ARW/SPC WRF AND QPF
OUTPUTS FROM GFS/NAM AND THE EC TO SOME DEGREE. BY SAT AFTERNOON AND
EVENING HOWEVER...INSTABILITY WILL BUILD /1000-1500 J/KG MUCAPE/
ACROSS SRN 2/3RDS OF REGION AS QUALITY WARM SECTOR BECOMES
ESTABLISHED WITH STRONG TO SEVERE THUNDERSTORMS POSSIBLE ONCE AGAIN.
MAIN RISKS CONTINUE TO BE WIND GUSTS OF 60 MPH..QUARTER HAIL...AND
ONE TR TWO TORNADOES CAN`T BE RULED OUT. LOW AND DEEP LAYER SHEAR
APPEAR MORE MARGINAL THAN PREVIOUS RUNS WITH REDUCED WIND SPEEDS
THROUGH THE VERTICAL COLUMN...POTENTIALLY REDUCING THE TORNADO
LIKELIHOOD HOWEVER. AREA BUFR SOUNDINGS INITIALLY SHOW LOW-LVL
CURVED HODOGRAPHS EARLY SATURDAY BUT QUICKLY BECOME UNIDIRECTIONAL
BEFORE INSTABILITY BUILDS. THE FRONT WILL SWEEP THROUGH BY LATE
SATURDAY NIGHT INTO SUNDAY MORNING WITH POTENTIAL FOR TRAILING
SHOWERS/ISOLATED TSTORMS BEHIND THE FRONT SUNDAY MORNING. /ALLEN/
LONG TERM...SUNDAY THROUGH FRIDAY...COME SUNDAY MORNING THE COLD
FRONT IS EXPECTED TO BE OVER OUR SOUTHEAST ZONES WHILE THE WEAKENING
CLOSED LOW CONTINUES OVER THE CENTRAL PLAINS. MODELS AGREE THAT THE
COLD FRONT WILL EXIT OUR SOUTHEAST MOST ZONES BEFORE NOON WHILE THE
CLOSED LOW MOVES OVER THE MID MISSISSIPPI VALLEY. SURFACE HIGH
PRESSURE CENTERED OVER THE CENTRAL PLAINS WILL BUILD INTO OUR AREA
IN THE WAKE OF THE COLD FRONT BRINGING COOLER AND DRIER AIR...BUT
OUR FLOW ALOFT WILL REMAIN SOUTHWESTERLY. MODELS STILL SHOW A WEAK
WAVE IN THE SOUTHWEST FLOW THAT MAY SQUEEZE OUT SOME LIGHT RAIN
SUNDAY NIGHT. MONDAY THE CLOSED LOW WILL SHIFT INTO THE OHIO VALLEY
WITH INDUCED MID LEVEL RIDGING MOVING OVER OUR CWA. THE SURFACE HIGH
WILL BE WEAKENING BUT SHIFT EAST OVER THE OZARKS MAINTAINING A DRY
NORTH LOW LEVEL FLOW ACROSS OUR CWA THROUGH MONDAY NIGHT. THIS WILL
RESULT IN COOLER AND DRIER WEATHER THROUGH MONDAY NIGHT. SPLIT FLOW
REGIME WILL CONTINUE THROUGH THE END OF THE WEAK WITH MODEL
DIFFERENCES EMERGING IN THE POSITION AN STRENGTH OF ANOTHER CLOSED
LOW AND NORTHERN STREAM DISTURBANCES. TUESDAY ANOTHER NORTHERN
STREAM SHORTWAVE WILL BE MOVING INTO THE CENTRAL PLAINS WHILE
ANOTHER CLOSED LOW MOVES OVER SOUTHERN CALIFORNIA. THE ECMWF IS
STRONGER WITH THE NORTHERN STREAM SHORTWAVE AND FARTHER SOUTH WITH
THE CLOSED LOW THAN THE GFS AND ENSEMBLES BY WEDNESDAY. WITH HIGH
PRESSURE AT THE SURFACE CONTINUING TO BE CENTERED NORTH OF OUR AREA
THE GULF WILL REMAIN CLOSED AND THE DISTURBANCE WILL HAVE LIMITED
MOISTURE TO WORK WITH. WL LEAN TOWARD THE ECMWF HERE AND CUT GFS MOS
POPS TUESDAY THROUGH WEDNESDAY. GREATER MODEL DIFFERENCES COME INTO
PLAY THURSDAY AND FRIDAY. THE GFS KEEPS THE CLOSED LOW NEAR BAJA
WHILE THE ECMWF IS FARTHER SOUTH WHILE THE ECMWF IS STRONGER WITH
ANOTHER NORTHERN STREAM SHORTWAVE. BOTH MODELS FOR DIFFERENT REASONS
AGREE THAT RAIN CHANCES WILL INCREASE LATE THURSDAY INTO FRIDAY DUE
TO THESE FEATURES SO HAVE ACCEPTED GFS POPS FOR FRIDAY. TEMPERATURES
WILL BE COOLER THROUGH THE PERIOD AS COMPARED TO THE LAST WEEK...BUT
AFTERNOON HIGHS AND MORNING LOWS WILL STILL REMAIN ABOVE NORMAL
THROUGH FRIDAY. /22/
&&
.AVIATION...
ROAD AREA OF MODERATE TO HEAVY SHOWERS WITH EMBEDDED
THUNDERSTORMS IS SHIFTING NNE ALONG THE MISSISSIPPI RIVER. +RA TO
+TSRA WILL BEGIN TO IMPACT KJAN AND KGLH OVER THE NEXT 1-2 HOURS.
KGWO AND KHBG WILL BE NEXT THROUGH THE EARLY MORNING HOURS AS
PRECIPITATION SPREAD NE TOWARDS KMEI AND KGTR BY LATE MORNING.
REDUCED VISIBILITIES OF 2SM AT TIMES IN HEAVIER DOWNPOURS WILL BE
POSSIBLE AS CIGS WILL DROP TO 0.7-1.5 KFT THROUGH THE EARLY AND LATE
MORNING HOURS. ADDITIONAL TURBULENCE CAN BE EXPECTED WITH STORM TOPS
NEAR 40 KFT. HEAVIER PRECIP WILL SHIFT NORTH OF REGION BY TONIGHT
WITH IFR CONDITIONS EXPECTED DUE TO LOW CIGS AND SOME PATCHY GROUND
FOG THRU SAT MORNING. /ALLEN/
&&
.PRELIMINARY POINT TEMPS/POPS...
JACKSON 66 60 75 50 / 100 44 88 69
MERIDIAN 66 58 74 54 / 91 52 80 85
VICKSBURG 68 61 75 46 / 100 54 89 45
HATTIESBURG 68 60 75 57 / 73 50 72 80
NATCHEZ 69 63 75 49 / 100 44 92 45
GREENVILLE 64 60 72 43 / 100 80 92 34
GREENWOOD 64 62 74 46 / 100 86 90 50
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...NONE.
LA...NONE.
AR...NONE.
&&
$$
28/50
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
412 PM CST FRI FEB 3 2012
.DISCUSSION...
Primary focus will be on the broad winter storm which per water
vapor imagery covers much of the Central and Southern Rockies.
Overall, models are in good agreement in ejecting the primary PV
anomaly northeast through KS and nw MO by 18z Saturday. Thereafter
the upper circulation becomes elongated as a strong shortwave dives
south through the Great Lakes and phases in with the storm system.
The net effect is the closed low will open up Saturday afternoon and
shear eastward and thus tear apart the deformation zone. This will
make it more difficult to cool the column via dynamic processes and
overcome the easterly flow of relatively mild/moist air being drawn
into the system. This in turn will slow down the change over to all
snow and thus limit snow amounts. Should still see enough snowfall
to impact driving conditions and thus warrants a winter weather
advisory for Saturday afternoon and evening.
At the surface an inverted surface trough extends northeast from a
low near SPS into central MO. A band of scattered convection tied to
the last of the significant shortwaves will track just north of this
inverted trough and affect the southeast third of the CWA with the
heaviest rains of the evening. Water vapor imagery shows a
pronounced dry slot which will strip away the deeper moisture above
the boundary layer and abruptly cut off any significant rainfall
with its passage. Satellite imagery suggests the dry slot is moving
faster than earlier anticipated and the 18z NAM...which has its
limits...is more in line with the 12z GFS which brought the dry slot
into the southwest CWA by 06z. Latest RUC now confirms this so have
lowered pops over the southwest third after midnight. Despite the
rain drying up as the dry slot passes through Bufr soundings and the
saturated boundary layer favors drizzle into Saturday
morning.
As noted above the upper system will be opening and filling up on
Saturday as it moves through the CWA. With a lack of cold air in
place the column will need to be cooled by dynamic cooling but that
will be weakening. Snowfall amounts will be muted and confined to
primarily north of a St Joseph to Macon line. One to two inches
possible over the far northwest corner of MO. Confidence is not
particularly high as there will be a battle between enough ice
nuclei available before it gets stripped away and sufficient cooling
in the boundary layer to support accumulating snow. While the snow
amounts are marginal for an advisory felt this winter has been so
short on snow and quite mild that best to treat this like the first
snow of the season and call attention to adjusting ones driving
habits.
Temperatures likely flatlining overnight as long as the inverted
trough stays south of the CWA. That should change on Saturday as the
surface low lifts north and drags this trough line towards the
Missouri River. So, temperatures will be a challenge within the warm
sector and if any sun breaks through the forecast highs will be too
conservative.
**NOTE** KEAX WSR-88D radar remains out of service while it is being
upgraded and will be unavailable through Feb 12.
MJ
Medium Range (Sunday through Friday)...
At the tail end of the weekend, remnants of the cutoff low, that is
bringing todays rain, will still be swirling over Missouri, making
for a messy looking rex block across the nation. However, the
remnants of the low will not stay in our vicinity long as a more
defined polar vortex drops into the Hudson Bay, shearing apart any
circulation that is still spinning around out there. This will mark
the transition from the rex to an omega like blocking pattern.
Operational and ensemble models are in really good agreement on the
late weekend development of the blocking pattern, so confidence
going into the beginning of next work week is rather good. Thus,
temperatures through much of the work week should stay around to
above normal owing to the lack of cold air under the blocking ridge,
and as the rex block transitions to a more generalized omega block,
there does not appear to be any potential for much in the way of
cold air to sink south. Otherwise, systems moving from west to east
will likely be shunt to our north or south, so dry weather is also
expected. Though, there will be a very weak shortwave sliding under
the blocking ridge Tuesday into Wednesday, which will need watching.
Cutter
&&
.AVIATION...
For the 18Z TAFs...stiff easterly winds advecting in somewhat drier
air have kept MVFR cigs at bay this morning but that is expected to
end very early in the forecast as MVFR cigs are now about to cross
the MO/KS state line. But the ifr cigs are still a ways off due to
these same easterly winds. Will push back IFR cigs till closer to
sunset. Once they arrive the ifr cigs will last through mid Saturday
morning. Area of showers and isolated thunderstorms over southern KS
will be moving into the terminals early this afternoon. Will leave
thunder out of terminals as it is very isolated now and airmass more
stable over west central MO.
While LIFR cigs may form later this evening think they will hold off
till pre-dawn hours of Saturday morning when dry slot aloft strips
away deeper moisture and leaves behind areas of drizzle. Expecting
to see marginal improvements to cigs by late morning.
Winds will remain quite strong through tonight with a gradual
weakening trends Saturday morning with the approach of the surface
low.
MJ
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY FROM NOON SATURDAY TO MIDNIGHT CST
SATURDAY NIGHT FOR MOZ001-002-011.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1050 AM CST FRI FEB 3 2012
.UPDATE...
/950 AM CST FRI FEB 3 2012/
12Z 850MB ANALYSIS SHOWS STOUT 35-40KT LLJ PUMPING UNSEASONABLY
HIGH AMOUNTS OF MOISTURE TO THE TUNE OF +10C DEWPOINT INTO THE
MISSOURI. SHROEDER RULE IN EFFECT...WITH MOISTURE CONVERGENCE
BEING MAXIMIZED ALONG THE 850MB WARM FRONT AS IT LIFTS NORTHEAST.
RAIN SHOWERS CONTINUE TO BLOSSOM AND WILL MOVE NORTHEAST
OVERSPREADING THE ENTIRE CWA LATE THIS MORNING AND INTO THE
AFTERNOON. DRY AIR NO MATCH FOR THIS AMOUNT OF FORCING AND
MOISTURE FLUX...WITH QUICK TOP DOWN SATURATION. CLOUDS AND
PRECIPITATION WILL LIMIT DIURNAL TEMPERATURE RISE...SO WILL BE
UNDERCUTTING HIGHS FOR TODAY. UPDATE COMING OUT SOON.
/907 AM CST FRI FEB 3 2012/
HAVE UPDATED FORECAST TO ACCOUNT FOR DEVELOPING WARM ADVECTION
RAIN SHOWERS DEVELOPING ACROSS OZARKS. THIS BATCH OF SHOWERS
SHOULD CONTINUE TO DEVELOP AND MOVE NORTHEAST...REACHING THE ST.
LOUIS METRO AROUND LUNCH TIME.
CVKING
&&
.DISCUSSION...
/310 AM CST FRI FEB 3 2012/
WET WEATHER STILL ON TAP FOR THE NEXT SEVERAL DAYS COURTESY OF THE
UPPER LOW SPINNING NEAR THE CO/NM BORDER. THE MODELS ARE IN PRETTY
DECENT AGREEMENT THROUGH THE FIRST 48H TRACKING THE UPPER LOW
THROUGH THE CENTRAL ROCKIES TODAY AND TO FAR NE KS BY SATURDAY
EVENING. IN RESPONSE THE ASSOCIATED SURFACE LOW WILL TRACK FROM
WESTERN TEXAS INTO SE KS BY DAYBREAK SATURDAY AND TO EXTREME
SOUTHERN IL BY EARLY SATURDAY EVENING.
THE INITIAL FORECAST PROBLEM WITH THIS SYSTEM IS THE TIMING OF THE
ONSET OF PRECIPITATION. THE MAJORITY OF THE LATEST MODEL RUNS HAVE
SLOWED THE EASTWARD DEVELOPMENT TODAY WITH THE NAM SUGGESTING THAT
RAIN WILL ONLY GET INTO CENTRAL MO BEFORE 00Z TONIGHT...WHILE THE
OTHER MODEL GUIDANCE BRINGS IT TO OR JUST EAST OF THE MS RIVER.
WHILE I`M INCLINED TO BELIEVE THIS MORNING WILL BE DRY...I THINK
RAIN WILL REALLY GET GOING THIS AFTERNOON AS LARGE SCALE ASCENT
OVERSPREADS MO AND MOISTURE TRANSPORT ACCELERATES DUE TO THE
INCREASINGLY SOUTHERLY LLJ. THE LAST HRRR RUN ALSO SUPPORTS THIS
NOTION...WITH RAIN MAKING IT TO THE MS RIVER BY 00Z...WHILE LOW
LEVEL DRY HOLDS IT AT BAY UNTIL THIS EVENING OVER MUCH OF IL. RAIN
WILL THEN SPREAD ACROSS IL THIS EVENING IN CONCERT WITH THE
ADVANCING STORM SYSTEM AND EASTWARD SHIFT OF LIFT AND MOISTURE
TRANSPORT. THE GUIDANCE CONTINUES TO SHOW ELEVATED INSTABILITY
SUPPORTING THE POTENTIAL FOR SOME EMBEDDED THUNDERSTORMS WITH
LOCALLY HEAVY RAIN.
DESPITE A RATHER BLOCKY UPPER AIR PATTERN THAT ENSUES ACROSS THE
WESTERN CONUS OVER THE NEXT TWO DAYS...IT APPEARS THAT UPPER LOW
WILL REMAIN PROGRESSIVE GETTING PICKED UP A NORTHERN STREAM UPPER
TROF DIGGING INTO THE EASTERN U.S. ON SATURDAY NIGHT. THIS SHOULD
AT LEAST SHUNT THE DYING UPPER LOW SEWD THROUGH THE AREA SATURDAY
NIGHT INTO SUNDAY. THIS ALLOWS SOME DEEPER COLD AIR TO INFILTRATE
ON SATURDAY NIGHT IN THE WAKE OF THE LOW LEVEL CYCLONE...BUT THE
SNOW POTENTIAL STILL LOOKS IFFY AND AT THIS POINT WILL JUST KEEP
WITH THE CURRENT FORECAST OF A CHANCE OF RAIN OR SNOW.
GLASS
&&
.AVIATION...
/1044 AM CST FRI FEB 3 2012/
IMPRESSIVE MOISTURE ADVECTION HAS LED TO THE ARRIVAL OF SHOWERS
SOONER THAN ANTICIPATED. BELIEVE THERE WILL BE ROUNDS OF RAIN
SHOWERS THAT WILL CONTINUE THROUGH THE TAF PERIOD WITH TOP DOWN
SATURATION OF THE ATMOSPHERE DROPPING CEILINGS FROM VFR TO IFR
TONIGHT. SHOULD SEE SYNOPTIC LIFT DECREASE TOMORROW
MORNING...TRANSITIONING PRECIPITATION FROM RAIN TO DRIZZLE. EAST
WIND 10 TO 15 KTS...WITH GUSTS TO 25 KTS WILL CONTINUE.
SPECIFICS FOR KSTL...
SHOWERS WILL OVERSPREAD THE TERMINAL BY 18Z...ALTHOUGH VFR
CEILINGS WILL LIKELY CONTINUE THROUGH AT LEAST 00Z. TOP DOWN
SATURATION OF ATMOSHERE WILL RESULT IN LOWERING CEILING TO IFR
LEVELS BY 06Z. PERIODS OF RAIN WILL CONTINUE OVERNIGHT
...TRANSITIONING TO DRIZZLE BY SATURDAY MORNING. EAST WIND 10 TO
15 KTS...WITH GUSTS TO 25KTS WILL CONTINUE.
CVKING
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS NORTH PLATTE NE
1201 PM CST FRI FEB 3 2012
.AVIATION...
MAJOR WINTER STORM IMPACTING MUCH OF WESTERN AND NORTH CENTRAL
NEBRASKA. BANDS OF HEAVY SNOW WILL CONTINUE TO IMPACT AVIATION
TRAVELS FROM SOUTHWEST INTO CENTRAL NEBRASKA INTO SATURDAY
MORNING. VISIBILITIES WILL BE REDUCED TO A MILE OR LESS DUE TO
MODERATE AND HEAVY SNOW AND NORTH TO NORTHEAST WINDS 20 TO 25 KTS.
CIGS ALSO IN THE OVC005 TO OVC015 RANGE. OVERNIGHT INCREASING SNOW
TOTALS WILL COMBINE WITH GUSTY WINDS TO PRODUCE PERIODS OF BLOWING
SNOW. FOR NORTHWESTERN INTO NORTH CENTRAL NEBRASKA...INCLUDING THE
VTN TERMINAL...THIS AREA WILL MISS OUT ON THE HEAVY SNOW
BANDS...HOWEVER LOW IFR CIGS WILL STILL BE LIKELY. TOMORROW THE
SYSTEM WILL EXIT TO THE EAST WITH RAPID IMPROVEMENT OF CONDITIONS
TO VFR DURING THE DAY.
&&
.PREV DISCUSSION... /ISSUED 911 AM CST FRI FEB 3 2012/
UPDATE...BASED ON INCOMING SNOWFALL REPORTS ACROSS THE CENTRAL
SANDHILLS...EXPANDED THE WINTER STORM WARNING TO ENCOMPASS
THOMAS...AND HOOKER COUNTIES AND ADDED EASTERN CHERRY COUNTY TO THE
WINTER WEATHER ADVISORY. BASED ON RADAR RETURNS AND LOCATION OF THE
DEFORMATION BAND...AND DUE TO THE EARLIER THAN EXPECTED CHANGEOVER
FROM RAIN TO SNOW...WENT AHEAD AND INCREASED ACCUMULATIONS ACROSS THE
NORTHERN PERIPHERY OF THE WARNING FOR MCPHERSON...NORTHERN
LINCOLN...LOGAN...HOOKER...THOMAS...BLAINE COUNTIES.
REAL TIME REPORTS AS WELL AS THE LATEST FORECAST STATEMENTS AND
INFORMATION ON THE STORM CAN BE ACCESSED AT THE FOLLOWING WEB SITE:
WWW.WEATHER.GOV/NORTHPLATTE
PREVIOUS DISCUSSION FOLLOWS...ISSUED AT 326 AM CST FRI FEB 3 2012
SHORT TERM...THIS HAS BEEN A CHALLENGING FORECAST THE LAST
COUPLE OF NIGHTS...AND UNFORTUNATELY THE IMPENDING WINTER STORM
CONTINUES TO BE HANDLED RATHER POORLY BY THE DETERMINISTIC MODEL
SOLUTIONS. MODELS CONTINUE TO WOBBLE NORTH AND SOUTH WITH THE AREA
OF POTENTIAL HEAVY SNOW. THIS IS LIKELY DUE TO CONVECTION/TSTMS
ACROSS THE SOUTHERN PLAINS CAUSING OVERALL MASS FIELD CHANGES FROM
MODEL RUN TO MODEL RUN. FEEL THAT ANY ONE PARTICULAR DETERMINISTIC
MODEL SOLUTION IS NOT WORTHY OF BASING A FORECAST ON DUE TO THIS
VARIABILITY. WILL SIDE TOWARD MORE OF AN ENSEMBLE/SREF BASED
APPROACH TO MAKING ANY FORECAST CHANGES THIS MORNING...AND USE THE
DETERMINISTIC MODELS MORE OR LESS AS GUIDANCE. DID APPEAR THAT THE
00Z NAM INITIALIZED A BIT BETTER THAN THE 00Z GFS BASED OFF WATER
VAPOR AND TROPOSPHERIC HEIGHTS. 00Z NAM SHOWS A NICE TROP FOLD
OVER WESTERN KS BY THIS EVENING...AND THIS IS WHEN THE DEEPENING
OF THE H7 LOW BEGINS. ALL MODELS INDICATE THIS PROCESS...BUT
DETERMINISTIC SOLUTIONS ARE DIFFERING ON EXACTLY WHERE THIS
DEEPENING AND SUBSEQUENT DEFORMATION BAND SET UP. CURRENT RUN OF
THE HRRR SUGGEST THE FIRST HINTS OF THE DEFORMATION BAND FORMING
FROM THE MCCOOK TO NORTH PLATTE AREA BY THE MIDDLE OF THIS
AFTERNOON...AND THAT GIVES SOMEWHAT OF A CONFIDENCE BOOST TO THE
GOING FORECAST. GIVEN THE MODEL VARIABILITY...FEEL THE BEST PLAN
IS TO LET THE CURRENT WARNINGS AND ADVISORIES CONTINUE AS
ARE...AND ONLY MAKE MINOR CHANGES TO THE CURRENT FORECAST. NORTH
WINDS DO INCREASE SOME THIS AFTERNOON...WITH GUSTS UP TO 30 MPH
EXPECTED BY THIS EVENING AS THE SFC LOW DEEPENS IN KS. THIS WILL
CAUSE SOME AREAS OF BLOWING SNOW AND REDUCED VISIBILITY. TOTAL
SNOWFALL ACCUMULATIONS BY SATURDAY NIGHT ARE EXPECTED TO RANGE
FROM 6 TO 11 INCHES ALONG AND SOUTHEAST OF AN ERICSON TO STAPLETON
TO BIG SPRINGS LINE. AMOUNTS GRADUALLY TAPER NORTHWEST OF THIS
LINE...WITH ONLY AN INCH OR SO EXPECTED AT THE NEBRASKA SOUTH
DAKOTA STATE LINE.
LONG TERM...12Z MONDAY THROUGH THURSDAY. NO MAJOR CHANGES TO THE
LONG TERM FORECAST. THE PROGRESSION AND OVERALL PERFORMANCE OF THE
UPPER LOW WILL HEAVILY DICTATE THE EXTENDED PERIOD...ESPECIALLY
SUNDAY AND MONDAY. WITH THE POTENTIAL OF SIGNIFICANT SNOW
ACCUMULATIONS ACROSS SOUTHWEST THROUGH SOUTH CENTRAL
NEBRASKA...GENERALLY KEPT LATEST HIGHS GOING...AND LOWERED MINS A
FEW DEGREES ACROSS THE EAST. TEMPERATURES TO REACH NEAR 35 ACROSS
THE SNOWPACK SOUTHWEST TO SOUTH CENTRAL NEBRASKA...WITH THE
POTENTIAL OF LOWER 40S ACROSS NORTHERN NEBRASKA WHERE LIGHT AMOUNTS
ARE EXPECTED. ATTENTION THEN TURNS TO A COLD FRONT AND ASSOCIATED
SHORTWAVE THAT WILL DROP SOUTH THROUGH THE NORTHERN HIGH PLAINS LATE
MONDAY NIGHT INTO TUESDAY. BESIDES COOLER TEMPERATURES WITH HIGHS
ONLY IN THE UPPER 20S TO LOWER 30S...THE LONG RANGE MODELS...MOST
NOTABLY THE GFS...DO GENERATE SPOTTY QPF AS THE WAVE EJECTS EAST.
MOST SHOULD BE FOCUSED NEAR THE FRONT RANGE OF WYOMING AND
COLORADO...BUT INTO THE ADJACENT PLAINS...INCLUDING SOUTHWEST
NEBRASKA...WHERE A SLIGHT CHANCE FOR LIGHT SNOW INTRODUCED TUESDAY.
REMAINDER OF EXTENDED CURRENTLY DRY...ALTHOUGH THE ECMWF DOES DROP
ANOTHER DISTURBANCE THROUGH THE CENTRAL HIGH PLAINS LATE WEDNESDAY
AND THURSDAY INCLUDING WESTERN NEBRASKA. THIS NOT SUPPORTED BY THE
GFS. TEMPERATURES SHOULD MODERATE TO THE MID 30S TO NEAR 40S
WEDNESDAY AND THE UPPER 30S/LOWERS 30S BY THURSDAY. IT SHOULD BE
NOTED THAT THE ARCTIC AIR WILL REMAIN WELL TO OUR NORTHEAST ACROSS
THE NORTHERN GREAT LAKES THURSDAY...AS UPPER RIDGING BECOMES
ESTABLISHED ACROSS THE WESTERN CONUS AND NORTHWESTERLY FLOW PREVAILS
ACROSS THE CENTRAL PLAINS.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...BLIZZARD WARNING UNTIL 5 PM
MST SATURDAY FOR NEZ056>058-069.
WINTER STORM WARNING UNTIL 6 PM CST /5 PM MST/ SATURDAY FOR
NEZ022-024>029-035>038-059-070-071.
WINTER WEATHER ADVISORY UNTIL 6 PM CST /5 PM MST/ SATURDAY FOR
NEZ005-008>010-023.
&&
$$
AVIATION...MASEK
AREA FORECAST DISCUSSION
NWS GRAND FORKS ND
221 PM CST FRI FEB 3 2012
.SHORT TERM...
THE MAIN CHALLENGE WILL BE FOG CONCERNS INITIALLY AND TEMPS.
MODELS ARE IN GOOD OVERALL AGREEMENT...WITH THE HRRR DOING WELL
WITH VSBYS IN THE NEAR TERM WITH FOG.
FOR TONIGHT...EXPECT AREAS OF DENSE FOG TO PERSIST ONCE AGAIN WITH
SFC HIGH PRESSURE OVERHEAD. THERE COULD BE A FEW BREAKS EARLY IN
THE WEST AND NORTH...BUT ANY CLEAR AREAS SHOULD QUICKLY FILL IN
WITH FOG AND LOW CLOUDS AFTER SUNSET. VSBYS WILL BE NEAR ZERO AT
TIMES ALONG WITH ISOLATED SLICK SPOTS GIVEN THE VERY DENSE FOG.
TEMPS SHOULD NOT GET TOO COLD AND MODELS ARE GOING A BIT TOO COLD
WITH LOW LEVEL MOISTURE AND FOG EXPECTED. WILL EXTEND THE DENSE
FOG ADVISORY FOR ALL AREAS THROUGH 18Z SAT.
FOR SATURDAY...EXPECT MORNING DENSE FOG TO DISSIPATE BY AFTERNOON
AS 925MB WINDS INCREASE A BIT AND SLIGHTLY BETTER MIXING IS
EXPECTED. TEMPS SHOULD WARM ABOVE NORMAL ONCE FOG DISSIPATES.
ON SUNDAY...850MB TEMPS WARM TO ABOUT +5C WITH WESTERLY SFC WINDS.
TEMPS COULD GET EVEN WARMER IN AREAS WITH LITTLE SNOW...AND IT
WILL BE WARM IN ALL AREAS WITH UPPER RIDGE OVERHEAD.
ON MONDAY...A COLD FRONT WILL DROP SOUTH FROM CANADA. THE NAM IS
THE STRONGEST/FASTEST WITH THE FRONT AND WOULD HAVE TEMPS FALLING
THROUGH THE DAY. THE ECMWF/GFS ARE A BIT SLOWER AND NOT AS STRONG.
IT SHOULD BE A DRY FROPA WITH PERHAPS SOME MID/HIGH CLOUDS AND
NORTHERLY WINDS COULD BECOME GUSTY BY AFTERNOON AND WILL INCREASE
WINDS IN THE VALLEY A BIT FROM GUIDANCE.
.LONG TERM (TUE-FRI)...
ALL LONG RANGE MODELS INDICATE A POLAR LOW DROPPING INTO ONTARIO
WITH A COOLER NORTHERLY FLOW ALOFT FOR OUR REGION. THEY DO DIFFER
ON THE EXTENT OF THE COLD AND HOW FAR WEST COLD AIR WILL GET. ECMWF
MAINTAINS THE COLDEST 850 MB TEMPS WHEREAS CANADIAN GEM THE
WARMEST. USING THE BLEND OF THE MODELS INDICATES HIGHS CLOSER TO
AVERAGE FOR THE MID TO LATE WEEK WITH MOSTLY TEENS TO LOWER 20S.
LOOKS DRY AS HIGH PRESSURE SETTLES OVER THE REGION.
&&
.AVIATION...
EXTENT OF FOG IS THE MAIN ISSUE. AREAS OF CLEARING THIS AFTN SHOULD
FOG BACK IN THIS EVENING AND BASED ON LIGHT WINDS AND STILL MOIST
BOUNDARY LAYER WOULD EXPECT WIDESPREAD 1/4SM VSBYS AGAIN OVERNIGHT
INTO MID MORNING SATURDAY. THEN DO ANTICIPATE MORE WIDESPREAD
CLEARING OF THE FOG MID TO LATE MORNING SATURDAY AS SFC WIND
GRADIENT IS A BIT HIGHER. WENT WITH THE ABOVE IDEA IN TAFS...BUT
HARD TO PINPOINT IF VSBYS WILL BE 3/4 OR 1/4SM AT ANY GIVEN TAF
OVERNIGHT INTO MID MORNING SATURDAY. WENT WITH MORE OF THE 1/4SM
IDEA DUE TO PAST 2 MORNINGS. CONFIDENCE IS MODERATE.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...DENSE FOG ADVISORY UNTIL NOON CST SATURDAY FOR NDZ006>008-
014>016-024-026>030-038-039-049-052>054.
MN...DENSE FOG ADVISORY UNTIL NOON CST SATURDAY FOR MNZ001>009-
013>017-022>024-027>032-040.
&&
$$
DK/RIDDLE
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
314 PM CST FRI FEB 3 2012
.DISCUSSION.../ISSUED AT 314 PM CST/
HAVE SEEN A BIT OF IMPROVEMENT IN VISIBILITY ACROSS SOUTHWEST MN THE
PAST COUPLE OF HOURS...NAMELY EAST OF THE RIDGE IN THE KMML AREA.
HRRR VISIBILITY FORECAST HAD ACTUALLY SHOWN THIS DELINEATION OVER
ITS PAST FEW RUNS...AND MAINTAINS HIGHER VISIBILITY IN KMML THROUGH
MUCH OF THE EVENING...WHILE ALSO SHOWING LOWER VISIBILITIES WORKING
WESTWARD INTO SD COUNTIES OF DENSE FOG ADVISORY BY 00Z. IF HRRR PANS
OUT AS SHOWN...CURRENT ADVISORY LOOKS GOOD WITH MINNEHAHA AND ROCK
COUNTIES ALSO SHOWING POTENTIAL FOR SUB-1/2SM VISIBILITIES. STRATUS
AND FOG SHOULD HOLD TEMPERATURES ACROSS THE NORTHERN CWA FAIRLY
STEADY OVERNIGHT...AND BUMPED UP LOWS FROM PREVIOUS FORECAST INTO
THE UPPER 20S.
AS FAR AS PRECIPITATION CHANCES OVER THE NEXT 24 HOURS...MAIN FOCUS
LOOKS TO REMAIN SOUTH OF THE AREA TOWARD I-80. HOWEVER...BOTH GFS
AND NAM SHOW AN AREA OF MID LEVEL FRONTOGENESIS LIFTING NORTH INTO
THE FAR SOUTHERN PART OF OUR CWA BY 09Z-12Z SATURDAY AS UPPER WAVE
LIFTS NORTHEAST ACROSS THE AREA. NAM SHOWING SOME WEAKENED STABILITY
ATOP THE FRONTAL SURFACE AROUND 12Z AS WELL...WHICH COULD RESULT IN
SOME HEAVIER SNOWFALL DURING THIS TIME. THAT WILL BE THE PERIOD OF
GREATEST CONCERN FOR SNOWFALL AMOUNTS...AND EVENING SHIFT WILL WANT
TO CLOSELY EXAMINE THIS TO SEE IF EVENING MODEL RUNS MAINTAIN THIS
FEATURE.
AS IS TYPICAL WITH THESE TYPE OF SYSTEMS...THERE WILL BE A SHARP
CUTOFF TO PRECIPITATION/SNOW AMOUNTS ALONG THE NORTHERN EDGE OF THE
SYSTEM...SO TRICKY PART OF THE FORECAST IS DETERMINING WHERE THAT
WILL BE. FOR NOW...GREATEST CONSENSUS FROM 12Z MODEL RUNS PUTS THE
GRADIENT IN OUR SOUTHERNMOST FOUR COUNTIES...WITH AMOUNTS FROM NEAR
ZERO ALONG HIGHWAY 3...TO 3-4 INCHES IN FAR SOUTHERN PORTIONS OF
WOODBURY/IDA COUNTIES. WITH BULK OF THE AREA BELOW 3 INCHES...HAVE
OPTED TO FORGO ADVISORY FOR NOW...BUT EVENING SHIFT WILL MONITOR
CLOSELY.
RELATIVELY QUIET PATTERN SETTING UP IN THE MID AND EXTENDED RANGE.
SURFACE HIGH PRESSURE SWINGS INTO THE WESTERN HIGH PLAINS BEHIND THE
DEPARTING LOW ON SATURDAY NIGHT AND SUNDAY. TEMPERATURES LOOK
RELATIVELY MILD BEHIND THE EXITING UPPER TROUGH WITH BENIGN
NORTHWEST FLOW TURN MORE WESTERLY BY MONDAY. WITH FRESH SNOWPACK
LIMITED TO THE EXTREME SOUTHEASTERN COUNTIES...TEMPERATURES WILL MIX
INTO THE LOWER 40S ON SUNDAY AND WILL IMPROVE TO THE MID 40S WITH
BETTER MIXING ON MONDAY. THE EXCEPTION WILL BE NEAR THE SUX AREA
WHICH WILL LIKELY BE A BIT COOLER WITH THE LINGERING SNOWPACK.
A WEAK UPPER TROUGH PUSHES THROUGH THE CENTRAL PLAINS MONDAY NIGHT
AND TUESDAY WITH LITTLE FANFARE OTHER THAN SOME INCREASED CLOUDS AND
SLIGHTLY COLDER TEMPERATURES CLOSE TO SEASONAL NORMALS. BEYOND
TUESDAY NIGHT...MODELS ONCE AGAIN DIVERGE QUITE A BIT. ALL MODELS
SHOW A CONTINUATION OF THE DRY PATTERN...HOWEVER THE ECMWF DEVELOPS
A DEEP UPPER LOW OVER THE GREAT LAKES AND INTRODUCES A STRONGER SHOT
OF COLD AIR LATE IN THE WEEK. DID KNOCK THE ALLBLEND TEMPERATURES
DOWN A FEW DEGREES LATE...BUT WITH A WARMER GFS SOLUTION...DID NOT
WANT TO DEVIATE TOO MUCH.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/
IFR-LIFR CONDITIONS EXPANDING WESTWARD ON EAST-NORTHEAST LOW LEVEL
FLOW OF MOISTURE TRAPPED BENEATH STRONG INVERSION. LIFR CONDITIONS
LIKELY TO PERSIST ALONG AND EAST OF THE BUFFALO RIDGE THROUGH THE
PERIOD. LIFR CEILINGS HAVE BACKED INTO KFSD AND WILL PERSIST THERE
AS WELL...WITH VISIBILITY LIKELY LOWERING INTO MVFR RANGE THROUGH
THE AFTERNOON. IFR-LIFR CEILINGS EXPECTED TO GRADUALLY CONTINUE
SPREADING OVER MOST OF THE AREA...THOUGH MISSOURI RIVER VALLEY AREAS
COULD BE SPARED AS THE LOWER LEVELS REMAIN MORE MIXED IN RESPONSE TO
STORM SYSTEM TO THE SOUTH. GRADUAL IMPROVEMENT POSSIBLE LATE IN THE
PERIOD AS WINDS BECOME MORE NORTHERLY...MOST LIKELY IN AREAS WEST OF
I-29 AFTER 12Z. THIS STORM SYSTEM WILL SPREAD CHANCE FOR RAIN/SNOW
INTO THE FAR SOUTHERN PARTS OF THE FORECAST AREA...AND KSUX COULD
SEE A PERIOD OF MVFR-IFR VISIBILITY IN -SN TONIGHT. /JH
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
IA...DENSE FOG ADVISORY UNTIL 9 AM CST SATURDAY FOR IAZ002-003.
MN...DENSE FOG ADVISORY UNTIL 9 AM CST SATURDAY FOR MNZ071-072-
080-081-089-090-097.
NE...NONE.
SD...DENSE FOG ADVISORY UNTIL 9 AM CST SATURDAY FOR SDZ039-040-
055-056.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1200 PM CST FRI FEB 3 2012
.SHORT TERM...TODAY THROUGH MONDAY
247 AM CST FRI FEB 3 2012
THE MAIN FOCUS IN THE SHORT TERM IS WITH THE CLOUD COVER AND DENSE
FOG AND WHEN THEY MAY CLEAR OUT.
CURRENTLY...A CLOSED MID LEVEL LOW IS PROPAGATING THROUGH THE
EASTERN ROCKIES WITH A RIDGE AXIS OUT AHEAD OF IT RUNNING ALONG
THE MISSISSIPPI RIVER. AT THE SURFACE...AN ELONGATED RIDGE OF HIGH
PRESSURE STRETCHES FROM THE MID ATLANTIC STATES NORTHWEST THROUGH
THE GREAT LAKES ON INTO THE NORTHERN PLAINS WHILE A LOW STARTS TO
TAKE SHAPE OVER WESTERN TEXAS. A WIDESPREAD BANK OF LOW LEVEL
STRATUS AND FOG ARE IN PLACE FROM THE DAKOTAS INTO THE GREAT LAKES
DUE TO MOISTURE STUCK UNDER A STEEP LOW LEVEL INVERSION. THIS
INVERSION INCREASES IN ITS BASE AS YOU GO TO THE NORTHEAST WITH
THE 03.00Z DVN SOUNDING SHOWING THE INVERSION STARTING AT THE
GROUND...WHERE 1/4SM VISIBILITY WAS BEING REPORTED...WHILE THE
03.00Z GRB SOUNDING WAS A LITTLE OFF THE DECK STARTING AT
900MB...WHERE VISIBILITY WAS P6SM WITH AN OVERCAST STRATUS DECK
AROUND 1KFT.
VISIBILITIES HAVE BEEN THE LOWEST ALONG THE WESTERN FRINGE OF THE
SURFACE RIDGE AXIS WHERE WINDS ARE LIGHT AND THE LOW LEVEL
MOISTURE IS TRAPPED UNDER THIS SHALLOW INVERSION. 03.00Z NAM/GFS
AND 03.06Z RUC SOUNDINGS SHOW THIS INVERSION AND LOW LEVEL
MOISTURE HOLDING ON THROUGH MUCH OF THE DAY BEFORE TRYING TO MIX
OUT THIS LAYER THIS AFTERNOON. CONFIDENCE IN THIS MIXING OUT
OCCURRING IS FAIRLY LOW GIVEN THE MODELS RECENT TRACK RECORD IN
TRYING TO CLEAR THE SKIES OUT. THAT SAID...WINDS DO PICK UP A BIT
OUT OF THE NORTHEAST AS THE LOW PRESSURE SYSTEM STRENGTHENS TO THE
SOUTH WHICH COULD HELP WITH THE MIXING. THUS...FOR NOW HAVE LEFT
THE DENSE FOG ADVISORY GOING UNTIL 18Z TODAY...BUT HAVE CHOPPED
OFF A FEW TIERS OF COUNTIES ACROSS CENTRAL WISCONSIN WHICH HAVE
NOT HAD ANY VISIBILITY ISSUES AND DO NOT APPEAR LIKELY TO DROP
THROUGH THE MORNING.
HOW FAST THE CLOUDS CLEAR OUT WILL PLAY A HUGE ROLE IN TEMPERATURES
THROUGH THE WEEKEND. WHERE SKIES CLEARED OUT ON
THURSDAY...TEMPERATURES SPIKED UP INTO THE 40S AND BROKE A RECORD AT
ROCHESTER. EVEN IF THE LOW LEVEL CLOUDS SCOUR OUT TODAY...THERE
SHOULD STILL BE AMPLE HIGH LEVEL CLOUD COVER IN PLACE DUE TO THE
STORM SYSTEM TO THE SOUTH. WITH CLOUDS POSSIBLY HOLDING ON LONGER
THAN FORECAST...HAVE GONE A BIT PESSIMISTIC ON TEMPERATURES OVER THE
NEXT FEW DAYS.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY
247 AM CST FRI FEB 3 2012
A COLD FRONT DROPS DOWN THROUGH THE REGION MONDAY NIGHT BUT THERE
IS NOT MUCH FORCING OR MOISTURE WITH ITS PASSAGE...SO IT SHOULD
COME THROUGH DRY. WHILE TEMPERATURES WILL DROP BEHIND THE
FRONT...THE MAIN POCKET OF COLD AIR WITH 850MB TEMPERATURES OF
AROUND -20C WILL TRACK OFF TO THE EAST TOWARD NEW ENGLAND. BEYOND
THIS...THE ONLY CHANCE FOR ANY SNOW WILL BE ON WEDNESDAY AS THE
REMNANTS OF A CUT OFF MID LEVEL LOW GET PICKED UP BY THE UPPER
LEVEL FLOW. THE 03.00Z ECMWF IS DEEPER WITH THIS LOW COMPARED TO
THE 03.00Z GFS WHICH JUST BRINGS AN OPEN WAVE THROUGH THE REGION.
REGARDLESS...THIS JUST LEAVES FOR A SLIGHT CHANCE OF SNOW ACROSS
THE FAR SOUTHERN PORTION OF THE FORECAST AREA BUT BEARS WATCHING.
&&
.AVIATION...THROUGH 18Z SATURDAY
1154 AM CST FRI FEB 3 2012
MAIN CONCERN IS ON THE FOG AND STRATUS THAT IS LINGERING OVER THE
UPPER MISSISSIPPI RIVER VALLEY REGION. VISIBILITIES HAVE SLOWLY
RISEN THIS MORNING TO MVFR AT KLSE AND IFR AT KRST. ANTICIPATING
THIS IMPROVEMENT TO CONTINUE THROUGH THE AFTERNOON...TOPPING OUT
AT VFR FOR KLSE AND MVFR AT KRST...AS DAYTIME MIXING AND SOME
LOWER SURFACE DEWPOINTS MOVE WEST ON THE NORTHEAST WINDS. CEILINGS
HAVE PERSISTED AT MVFR AT KLSE AND LIFR AT KRST. THESE MAY NOT
CHANGE MUCH...THOUGH...DUE TO TRAPPED MOISTURE BELOW AN INVERSION.
KEPT KLSE AT MVFR AND KRST ONLY CLIMBING TO IFR.
TONIGHT INTO SATURDAY MORNING IS A LITTLE TRICKY. AN INCREASING
EAST-NORTHEAST WIND INDUCED BY LOW PRESSURE TRACKING TOWARDS
KANSAS CITY SHOULD KEEP THE NEAR SURFACE AIR MORE MIXED THAN THE
LAST TWO NIGHTS. AS SUCH...VISIBILITIES MAY HAVE A HARDER TIME
DROPPING...IF AT ALL. IMPROVED THE KRST TAF TO ONLY LOWER TO
IFR THIS EVENING...BUT IT IS POSSIBLE THEY STAY MVFR OR EVEN CLIMB
TO VFR. AT KLSE...ANTICIPATING VISIBILITIES TO STAY VFR. CEILINGS
AGAIN ARE NOT EXPECTED TO RISE MUCH FROM THE AFTERNOON. LATE
SATURDAY MORNING...THERE ARE SIGNALS FOR THE LOW STRATUS TO
SCATTER OUT. GIVEN THAT IT IS NEAR THE END OF THE TAF PERIOD...
HAVE ONLY SIGNALED THIS BY A BROKEN DECK. HOWEVER...THERE IS
OPTIMISM FOR THIS TO OCCUR...NOTED BY CLEARING TODAY TAKING PLACE
OVER NORTHERN WISCONSIN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
1200 PM CST FRI FEB 3 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1154 AM CST FRI FEB 3 2012
.SHORT TERM...TODAY THROUGH MONDAY
247 AM CST FRI FEB 3 2012
THE MAIN FOCUS IN THE SHORT TERM IS WITH THE CLOUD COVER AND DENSE
FOG AND WHEN THEY MAY CLEAR OUT.
CURRENTLY...A CLOSED MID LEVEL LOW IS PROPAGATING THROUGH THE
EASTERN ROCKIES WITH A RIDGE AXIS OUT AHEAD OF IT RUNNING ALONG
THE MISSISSIPPI RIVER. AT THE SURFACE...AN ELONGATED RIDGE OF HIGH
PRESSURE STRETCHES FROM THE MID ATLANTIC STATES NORTHWEST THROUGH
THE GREAT LAKES ON INTO THE NORTHERN PLAINS WHILE A LOW STARTS TO
TAKE SHAPE OVER WESTERN TEXAS. A WIDESPREAD BANK OF LOW LEVEL
STRATUS AND FOG ARE IN PLACE FROM THE DAKOTAS INTO THE GREAT LAKES
DUE TO MOISTURE STUCK UNDER A STEEP LOW LEVEL INVERSION. THIS
INVERSION INCREASES IN ITS BASE AS YOU GO TO THE NORTHEAST WITH
THE 03.00Z DVN SOUNDING SHOWING THE INVERSION STARTING AT THE
GROUND...WHERE 1/4SM VISIBILITY WAS BEING REPORTED...WHILE THE
03.00Z GRB SOUNDING WAS A LITTLE OFF THE DECK STARTING AT
900MB...WHERE VISIBILITY WAS P6SM WITH AN OVERCAST STRATUS DECK
AROUND 1KFT.
VISIBILITIES HAVE BEEN THE LOWEST ALONG THE WESTERN FRINGE OF THE
SURFACE RIDGE AXIS WHERE WINDS ARE LIGHT AND THE LOW LEVEL
MOISTURE IS TRAPPED UNDER THIS SHALLOW INVERSION. 03.00Z NAM/GFS
AND 03.06Z RUC SOUNDINGS SHOW THIS INVERSION AND LOW LEVEL
MOISTURE HOLDING ON THROUGH MUCH OF THE DAY BEFORE TRYING TO MIX
OUT THIS LAYER THIS AFTERNOON. CONFIDENCE IN THIS MIXING OUT
OCCURRING IS FAIRLY LOW GIVEN THE MODELS RECENT TRACK RECORD IN
TRYING TO CLEAR THE SKIES OUT. THAT SAID...WINDS DO PICK UP A BIT
OUT OF THE NORTHEAST AS THE LOW PRESSURE SYSTEM STRENGTHENS TO THE
SOUTH WHICH COULD HELP WITH THE MIXING. THUS...FOR NOW HAVE LEFT
THE DENSE FOG ADVISORY GOING UNTIL 18Z TODAY...BUT HAVE CHOPPED
OFF A FEW TIERS OF COUNTIES ACROSS CENTRAL WISCONSIN WHICH HAVE
NOT HAD ANY VISIBILITY ISSUES AND DO NOT APPEAR LIKELY TO DROP
THROUGH THE MORNING.
HOW FAST THE CLOUDS CLEAR OUT WILL PLAY A HUGE ROLE IN TEMPERATURES
THROUGH THE WEEKEND. WHERE SKIES CLEARED OUT ON
THURSDAY...TEMPERATURES SPIKED UP INTO THE 40S AND BROKE A RECORD AT
ROCHESTER. EVEN IF THE LOW LEVEL CLOUDS SCOUR OUT TODAY...THERE
SHOULD STILL BE AMPLE HIGH LEVEL CLOUD COVER IN PLACE DUE TO THE
STORM SYSTEM TO THE SOUTH. WITH CLOUDS POSSIBLY HOLDING ON LONGER
THAN FORECAST...HAVE GONE A BIT PESSIMISTIC ON TEMPERATURES OVER THE
NEXT FEW DAYS.
.LONG TERM...MONDAY NIGHT THROUGH THURSDAY
247 AM CST FRI FEB 3 2012
A COLD FRONT DROPS DOWN THROUGH THE REGION MONDAY NIGHT BUT THERE
IS NOT MUCH FORCING OR MOISTURE WITH ITS PASSAGE...SO IT SHOULD
COME THROUGH DRY. WHILE TEMPERATURES WILL DROP BEHIND THE
FRONT...THE MAIN POCKET OF COLD AIR WITH 850MB TEMPERATURES OF
AROUND -20C WILL TRACK OFF TO THE EAST TOWARD NEW ENGLAND. BEYOND
THIS...THE ONLY CHANCE FOR ANY SNOW WILL BE ON WEDNESDAY AS THE
REMNANTS OF A CUT OFF MID LEVEL LOW GET PICKED UP BY THE UPPER
LEVEL FLOW. THE 03.00Z ECMWF IS DEEPER WITH THIS LOW COMPARED TO
THE 03.00Z GFS WHICH JUST BRINGS AN OPEN WAVE THROUGH THE REGION.
REGARDLESS...THIS JUST LEAVES FOR A SLIGHT CHANCE OF SNOW ACROSS
THE FAR SOUTHERN PORTION OF THE FORECAST AREA BUT BEARS WATCHING.
&&
.AVIATION...THROUGH 18Z SATURDAY
1154 AM CST FRI FEB 3 2012
MAIN CONCERN IS ON THE FOG AND STRATUS THAT IS LINGERING OVER THE
UPPER MISSISSIPPI RIVER VALLEY REGION. VISIBILITIES HAVE SLOWLY
RISEN THIS MORNING TO MVFR AT KLSE AND IFR AT KRST. ANTICIPATING
THIS IMPROVEMENT TO CONTINUE THROUGH THE AFTERNOON...TOPPING OUT
AT VFR FOR KLSE AND MVFR AT KRST...AS DAYTIME MIXING AND SOME
LOWER SURFACE DEWPOINTS MOVE WEST ON THE NORTHEAST WINDS. CEILINGS
HAVE PERSISTED AT MVFR AT KLSE AND LIFR AT KRST. THESE MAY NOT
CHANGE MUCH...THOUGH...DUE TO TRAPPED MOISTURE BELOW AN INVERSION.
KEPT KLSE AT MVFR AND KRST ONLY CLIMBING TO IFR.
TONIGHT INTO SATURDAY MORNING IS A LITTLE TRICKY. AN INCREASING
EAST-NORTHEAST WIND INDUCED BY LOW PRESSURE TRACKING TOWARDS
KANSAS CITY SHOULD KEEP THE NEAR SURFACE AIR MORE MIXED THAN THE
LAST TWO NIGHTS. AS SUCH...VISIBILITIES MAY HAVE A HARDER TIME
DROPPING...IF AT ALL. IMPROVED THE KRST TAF TO ONLY LOWER TO
IFR THIS EVENING...BUT IT IS POSSIBLE THEY STAY MVFR OR EVEN CLIMB
TO VFR. AT KLSE...ANTICIPATING VISIBILITIES TO STAY VFR. CEILINGS
AGAIN ARE NOT EXPECTED TO RISE MUCH FROM THE AFTERNOON. LATE
SATURDAY MORNING...THERE ARE SIGNALS FOR THE LOW STRATUS TO
SCATTER OUT. GIVEN THAT IT IS NEAR THE END OF THE TAF PERIOD...
HAVE ONLY SIGNALED THIS BY A BROKEN DECK. HOWEVER...THERE IS
OPTIMISM FOR THIS TO OCCUR...NOTED BY CLEARING TODAY TAKING PLACE
OVER NORTHERN WISCONSIN.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR WIZ054-061.
MN...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR MNZ079-086>088-
094>096.
IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ008>011-018-019-
029-030.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...AJ