Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/05/12
AREA FORECAST DISCUSSION
NWS MIAMI FL
836 PM EST SAT FEB 4 2012
.UPDATE...
NO CHANGES TO THE EXISTING FORECAST AT THIS TIME ...
SHOWERS CONTINUE TO AFFECT THE COASTAL WATERS OF THE EAST COAST, MAINLY
SECTIONS OF BROWARD AND PALM BEACH COUNTIES THIS EVENING. ISOLATED
TO SCATTERED SHOWERS WILL CONTINUE TONIGHT DUE TO THE MODERATE
EASTERLY FLOW AND SUFFICIENT MOISTURE DEPTH. WARM TEMPERATURES CAN
BE EXPECTED AGAIN TONIGHT WITH LOWS IN THE 60S TO AROUND 70.
THE RUC RAPID REFRESH MODEL FOR TONIGHT GENERATES CONVECTIVE
ACTIVITY OVER THE GULF OF MEXICO OUTSIDE OF THE GULF COASTAL
WATERS. HOWEVER, IT HINTS AT INCREASED SHOWER ACTIVITY TOWARD THE
EARLY MORNING HOURS OVER MIAMI-DADE AND BROWARD. THE SPC MESOSCALE
ANALYSIS SHOWS MOISTURE CONVERGENCE AND AN INCREASE IN THETA AND
MIXING RATION BETWEEN BROWARD AND PALM BEACH COUNTIES FOR THE PAST HOUR,
WHICH COINCIDES WITH THE AREA OF SHOWER ACTIVITY OBSERVED AT THE
PRESENT TIME.
THE FORECAST REASONING REMAINS UNCHANGED. AN UPPER LEVEL
TROUGH THAT EXTENDS FROM THE YUCATAN INTO THE CENTRAL/EASTERN
GULF WILL MOVE TOWARDS SOUTH FLORIDA/FLORIDA STRAITS ON SUNDAY
INTO MONDAY...WITH PWATS SLOWLY INCREASING THROUGH THIS TIME. THE
PRECIP AMOUNTS ARE STILL EXPECTED TO BE ON THE LIGHT TO MODERATE
SIDE...WITH RAINFALL TOTALS OF 1/4 TO 1/2 AN INCH FOR THE NAPLES
AND WEST OF LAKE OKEECHOBEE...AND 1/2 TO 1.5 INCHES FOR THE EAST
COAST METRO REGIONS.
&&
.PREV DISCUSSION... /ISSUED 704 PM EST SAT FEB 4 2012/
AVIATION...LITTLE CHANGE IN THE EXPECTED CONDITIONS OVER THE NEXT
12 HOURS WITH CONTINUED EASTERLY FLOW AND ISOLATED TO SCATTERED
SHOWER ACTIVITY. CEILINGS WILL BECOME A BIT LOWER OVERNIGHT WITH
BRIEF MVFR CONDITIONS POSSIBLE, EXCEPT AT KPBI, WHERE THEY WILL
BE MORE PREVALENT. WINDS WILL BECOME SOUTHEAST AT 10-13 KNOTS BY
SUNDAY MORNING WITH SHOWER ACTIVITY SLOWLY BECOMING MORE NUMEROUS
THROUGHOUT THE DAY. A FEW TSRA COULD FORM BY SUNDAY AFTERNOON,
BUT WILL ONLY MENTION VCSH AT THIS TIME.
PREV DISCUSSION... /ISSUED 303 PM EST SAT FEB 4 2012/
DISCUSSION...
SURFACE HIGH PRESSURE IS MOVING EAST INTO THE ATLANTIC AS LOW
PRESSURE MOVES INTO THE TENNESSEE VALLEY. THIS WILL ALLOW THE
PRESSURE GRADIENT TO SLOWLY RELAX TONIGHT AND SUNDAY...WITH WINDS
VEERING TO THE SOUTHEAST. ISOLATED TO SCATTERED SHOWERS WILL
CONTINUE TONIGHT DUE TO THE MODERATE EASTERLY FLOW AND SUFFICIENT
MOISTURE DEPTH. WARM TEMPERATURES CAN BE EXPECTED AGAIN TONIGHT
WITH LOWS IN THE 60S TO AROUND 70. MOSTLY CLOUDY SKIES CAN BE
EXPECTED TONIGHT THROUGH THE BEGINNING OF NEXT WEEK DUE TO UPPER
LEVEL CLOUDINESS FROM A LOW LEVEL TROUGH THAT EXTENDS FROM THE
YUCATAN INTO THE CENTRAL/EASTERN GULF. THIS FEATURE WILL MOVE
TOWARDS SOUTH FLORIDA/FLORIDA STRAITS ON SUNDAY INTO MONDAY...WITH
PWATS SLOWLY INCREASING THROUGH THIS TIME. MODEL SOLUTIONS DIFFER
ON HOW FAST AND HOW FAR NORTH THE LOW/MID LEVEL MOISTURE WILL MOVE
INTO THE REGION. THE GFS HAS THE MOISTURE FURTHER NORTH THAN THE
ECMWF ON THE 12Z RUNS...BRINGING THE MOISTURE IN MOST OF THE
REGION LATE SUNDAY AFTERNOON THROUGH MONDAY MORNING. THE ECMWF
ONLY BRINGS IN THE DEEPEST MOISTURE TO THE SOUTHERN PORTION OF THE
REGION. THIS DIFFERS FROM THE 00Z RUN...AND THE 00Z SOLUTION WAS
MORE SIMILAR TO THE GFS. HOWEVER...IT APPEARS THAT MUCH NEEDED
RAINFALL WILL BE MOVING INTO THE REGION LATE SUNDAY THROUGH
MONDAY.
THE RIGHT ENTRANCE REGION OF A WEAK UPPER JET WILL BE OVER THE
REGION SUNDAY AFTERNOON INTO THE SUNDAY EVENING AND THIS WILL
ENHANCE LIFT AT THE SAME TIME MOISTURE IS INCREASING OVER THE
REGION. SO KEPT CHANCE POPS SUNDAY FOR MOST OF SOUTH FLORIDA.
BUMPED UP POPS TO HIGH END CHANCE TO LIKELY FOR THE SOUTHERN AND
SOUTHEAST PORTIONS OF THE CWA FOR SUNDAY NIGHT. ALSO KEPT MENTION
OF THUNDER FOR THE SOUTHERN HALF OF THE REGION FOR SUNDAY
AFTERNOON AND SUNDAY NIGHT. THE DEEPER MOISTURE MAY BE MOVING OUT
OF THE REGION MONDAY MORNING...BUT A WEAK FRONTAL BOUNDARY IS
EXPECTED TO MOVE TOWARDS SOUTH FLORIDA. THE LOW LEVEL TROUGH MAY
ALSO STAY OVER THE REGION THROUGH MONDAY AFTERNOON. SO BUMPED UP
POPS TO CHANCE TO LIKELY ACROSS THE REGION ON MONDAY. ATTM...IT
APPEARS THE PRECIP AMOUNTS MAY BE ON THE LIGHT TO MODERATE
SIDE...WITH RAINFALL TOTALS OF 1/4 TO 1/2 AN INCH FOR THE NAPLES
AND WEST OF LAKE OKEECHOBEE...AND 1/2 TO 1.5 INCHES FOR THE EAST
COAST METRO REGIONS. WENT BELOW GUIDANCE FOR HIGH TEMPERATURES ON
MONDAY BY A COUPLE DEGREES DUE TO EXPECTED CLOUD COVER AND
RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 79 67 77 / 20 30 50 50
FORT LAUDERDALE 72 79 67 79 / 30 40 60 60
MIAMI 72 80 67 79 / 30 40 60 60
NAPLES 67 80 65 79 / 10 30 30 30
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...71/JE
AVIATION/RADAR...14/MJB
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
901 PM CST SAT FEB 4 2012
.UPDATE PUBLIC DISCUSSION...
.SHORT TERM /TONIGHT/...
...CONTINUE TO TRIM BACK ADVISORY. EASTERN AREAS OF LIGHT SNOW
NEARLY OVER AND SOUTHWEST CONTINUES LIGHT. WARNING AREA STILL
RECEIVING SOME ADDITIONAL LIGHT SNOW. ALL WILL EXPIRE AT 06Z.
NEXT ISSUE IS FOG AND LOW STRATUS. EXPECTING LOW STRATUS AND FOG TO
OVERTAKE NORTHERN BORDER COUNTIES NEAR MN BORDER BY 06Z AND
TRANSLATE SOUTH TO NEAR DES MOINES BY 12Z. HAVE ADDED AREAS FOG
NORTH AND MAINTAIN PATCHY FOG SOUTH. IF SKIES CLEAR AND FOG GETS A
FOOTHOLD...MAY BE SOME DENSE FOG. DIFFICULT TO DECIDE WHAT AREAS
MIGHT BE AT RISK FOR THAT...GIVEN APPROACHING CLOUDS. UPSTREAM
VISBYS LAST NIGHT WERE AT OR ABOVE 1/2SM SO...MIGHT NOT BE A MAJOR
ISSUE WITH THE EXCEPTION OF FROSTY ROAD SURFACES. WILL NEED TO
MONITOR THROUGH THE NIGHT.
HAVE TRIMMED BACK WINTER STORM WARNING WITH THE EXCEPTION OF WHERE
SNOW STILL FALLING IN SW IA. LEAVING ADVISORY AS IS...DUE TO BAND OF
SNOW STILL OCCURRING IN DEF ZONE OVER THE SOUTHEAST. MONITORING AREA
FOR FOG DEVELOPMENT LATE TONIGHT. ADVECTION FOG OVER MN AND
POTENTIAL FOR RADIATION FOG OVER IOWA MAY COMPLICATE TRAVEL
OVERNIGHT AND EARLY SUNDAY MORNING.
.PREVIOUS SHORT TERM /TONIGHT/...
PRIMARY CONCERNS REMAIN SNOW TRENDS. RADAR AND SATELLITE
OBSERVATIONS INDICATE THAT PRECIP INTENSITY IS BEGINNING TO WANE
WITH TOPS WARMING AND ECHOES DIMINISHING. MODELS CONFIRM THIS AS
WELL WITH 18Z RUC UVM AND MOISTURE BOTH DECREASING IN DENDRITIC
GROWTH ZONE AROUND H6/H5 OR 300K ISENT SURFACE. THIS THINKING HAS
LEAD TO CATEGORICAL POPS WITH LITTLE ADDITIONAL ACCUMULATION THROUGH
00Z...FOLLOWED BY FURTHER DECREASE IN POPS AND NORTH TO SOUTH
COVERAGE LATER THIS EVENING. MOST LOCAL VISIBILITIES ARE NOW 1SM OR
GREATER. HEADLINES WERE TRIMMED TO 06Z THIS AFTERNOON AND COULD
VERY WELL NEED TO BE CANCELLED EVEN EARLIER THIS EVENING IF TRENDS
CONTINUE.
NEXT CONCERN TURNS TO CONDITIONS OVERNIGHT. VERY SHALLOW STRATUS
AND FOG WAS MAKING HEADWAY SOUTH EARLIER THIS AFTERNOON BUT THAT HAS
NOW ERODED. LOW LEVEL WINDS WILL LIKELY BE JUST STRONG ENOUGH TO
PRECLUDE WIDESPREAD DENSE FOG. HOWEVER 21Z SURFACE ANALYSIS SHOWS
LACK OF MUCH DRYING UPSTREAM SO HAVE MENTIONED PATCHY FOG FOR A
START IN CASE THIS MOISTURE AREA DOES INDEED FILL BACK IN AGAIN.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LOW WILL HAVE PUSHED FURTHER EAST FOR BEGINNING OF PERIOD...WITH
HIGH PRESSURE PUSHING IN. HAVE INCLUDED MENTION FOR FOG ACROSS THE
NORTH EARLY SUNDAY MORNING...AND SHOULD LIFT BY LATE MORNING.
COULD AGAIN SEE FOG EARLY MONDAY...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE MENTION ATTM. LOW OVER ROCKIES WILL DEEPEN...AND REMAIN
OVER ROCKIES THROUGH TUESDAY WITH SPLIT FLOW OVER REGION.
TEMPERATURES WILL WARM INTO MONDAY WITH WAA AND WEAK RIDGING OVER
IOWA.
STRONG WAVE WILL PUSH LOW OUT OF ROCKIES TUESDAY. THIS WILL BRING
A CHANCE FOR PRECIPITATION ACROSS IOWA. MODELS DO NOT HAVE GOOD RUN-
TO-RUN CONSISTENCY WITH TRACK OF LOW...BUT ARE BEGINNING TO PULL IT
FURTHER NORTH. HAVE INCLUDED SLIGHT CHANCE FOR PRECIPITATION
ACROSS SOUTHERN IOWA FOR TUESDAY INTO WEDNESDAY. WILL LIKELY SEE
RAIN CHANGING OVER TO SNOW. CURRENTLY...LIFT IS A BIT
LACKING...AND PRECIPITATION WILL LIKELY BE LIGHT.
BEHIND LOW...ANOTHER FRONTAL BOUNDARY WILL PUSH DOWN FROM CANADA.
ATTM APPEARS FROPA WILL BE DRY. MUCH COLDER AIR WILL WORK IN
BEHIND FRONT AND TEMPERATURES WILL GRADUALLY COOL TOWARDS END OF
PERIOD.
&&
.AVIATION...05/00Z
SYSTEM BEGINNING TO WEAKEN AS DEF ZONE LOSING SUPPORT FROM MAIN
UPPER LEVEL LOW PULLING OFF THE THE SOUTHEAST OF IA THIS EVENING.
CONSEQUENTLY...CIGS AND VSBYS WILL CONTINUE TO IMPROVE FOR THE SHORT
TERM WITH GENERALLY VFR FOR A SHORT PERIOD OF TIME. HOWEVER...BY MID
TO LATE EVENING AFT 05Z FOG POTENTIAL WILL INCREASE. FRESH SNOW
COVER AND CLEARING SKIES ALONG WITH AMPLE MOISTURE IN THE BOUNDARY
LAYER MAY LEAD TO FOG. QUESTION ABOUT MOISTURE DEPOSITION OR IF IT
REMAINS SUSPENDED. WINDS WILL REMAIN IN THE 7 TO 8KT RANGE...SO THIS
MAY HELP THE AIRMASS REMAIN MIXED AS THE ENTIRE COLUMN COOLS TO
SATURATION. THOUGH CONFIDENCE LOW...MAY NEED TO UPDATE FOR LIFR FOG
AND OR CIGS LATER THIS EVENING IF TRENDS FOR THICK FOG ARE
CONFIRMED. THEN...PERIOD OF MOST CONCERN WOULD SHIFT TO 10-15Z
SUNDAY MORNING. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ADAMS-CASS.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR
RINGGOLD-TAYLOR.
&&
$$
SHORT TERM...SMALL/REV
LONG TERM...AWB
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
727 PM CST SAT FEB 4 2012
.UPDATE PUBLIC DISCUSSION...
.SHORT TERM /TONIGHT/...
HAVE TRIMMED BACK WINTER STORM WARNING WITH THE EXCEPTION OF WHERE
SNOW STILL FALLING IN SW IA. LEAVING ADVISORY AS IS...DUE TO BAND OF
SNOW STILL OCCURRING IN DEF ZONE OVER THE SOUTHEAST. MONITORING AREA
FOR FOG DEVELOPMENT LATE TONIGHT. ADVECTION FOG OVER MN AND
POTENTIAL FOR RADIATION FOG OVER IOWA MAY COMPLICATE TRAVEL
OVERNIGHT AND EARLY SUNDAY MORNING.
.PREVIOUS SHORT TERM /TONIGHT/...
PRIMARY CONCERNS REMAIN SNOW TRENDS. RADAR AND SATELLITE
OBSERVATIONS INDICATE THAT PRECIP INTENSITY IS BEGINNING TO WANE
WITH TOPS WARMING AND ECHOES DIMINISHING. MODELS CONFIRM THIS AS
WELL WITH 18Z RUC UVM AND MOISTURE BOTH DECREASING IN DENDRITIC
GROWTH ZONE AROUND H6/H5 OR 300K ISENT SURFACE. THIS THINKING HAS
LEAD TO CATEGORICAL POPS WITH LITTLE ADDITIONAL ACCUMULATION THROUGH
00Z...FOLLOWED BY FURTHER DECREASE IN POPS AND NORTH TO SOUTH
COVERAGE LATER THIS EVENING. MOST LOCAL VISIBILITIES ARE NOW 1SM OR
GREATER. HEADLINES WERE TRIMMED TO 06Z THIS AFTERNOON AND COULD
VERY WELL NEED TO BE CANCELLED EVEN EARLIER THIS EVENING IF TRENDS
CONTINUE.
NEXT CONCERN TURNS TO CONDITIONS OVERNIGHT. VERY SHALLOW STRATUS
AND FOG WAS MAKING HEADWAY SOUTH EARLIER THIS AFTERNOON BUT THAT HAS
NOW ERODED. LOW LEVEL WINDS WILL LIKELY BE JUST STRONG ENOUGH TO
PRECLUDE WIDESPREAD DENSE FOG. HOWEVER 21Z SURFACE ANALYSIS SHOWS
LACK OF MUCH DRYING UPSTREAM SO HAVE MENTIONED PATCHY FOG FOR A
START IN CASE THIS MOISTURE AREA DOES INDEED FILL BACK IN AGAIN.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LOW WILL HAVE PUSHED FURTHER EAST FOR BEGINNING OF PERIOD...WITH
HIGH PRESSURE PUSHING IN. HAVE INCLUDED MENTION FOR FOG ACROSS THE
NORTH EARLY SUNDAY MORNING...AND SHOULD LIFT BY LATE MORNING.
COULD AGAIN SEE FOG EARLY MONDAY...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE MENTION ATTM. LOW OVER ROCKIES WILL DEEPEN...AND REMAIN
OVER ROCKIES THROUGH TUESDAY WITH SPLIT FLOW OVER REGION.
TEMPERATURES WILL WARM INTO MONDAY WITH WAA AND WEAK RIDGING OVER
IOWA.
STRONG WAVE WILL PUSH LOW OUT OF ROCKIES TUESDAY. THIS WILL BRING
A CHANCE FOR PRECIPITATION ACROSS IOWA. MODELS DO NOT HAVE GOOD RUN-
TO-RUN CONSISTENCY WITH TRACK OF LOW...BUT ARE BEGINNING TO PULL IT
FURTHER NORTH. HAVE INCLUDED SLIGHT CHANCE FOR PRECIPITATION
ACROSS SOUTHERN IOWA FOR TUESDAY INTO WEDNESDAY. WILL LIKELY SEE
RAIN CHANGING OVER TO SNOW. CURRENTLY...LIFT IS A BIT
LACKING...AND PRECIPITATION WILL LIKELY BE LIGHT.
BEHIND LOW...ANOTHER FRONTAL BOUNDARY WILL PUSH DOWN FROM CANADA.
ATTM APPEARS FROPA WILL BE DRY. MUCH COLDER AIR WILL WORK IN
BEHIND FRONT AND TEMPERATURES WILL GRADUALLY COOL TOWARDS END OF
PERIOD.
&&
.AVIATION...05/00Z
SYSTEM BEGINNING TO WEAKEN AS DEF ZONE LOSING SUPPORT FROM MAIN
UPPER LEVEL LOW PULLING OFF THE THE SOUTHEAST OF IA THIS EVENING.
CONSEQUENTLY...CIGS AND VSBYS WILL CONTINUE TO IMPROVE FOR THE SHORT
TERM WITH GENERALLY VFR FOR A SHORT PERIOD OF TIME. HOWEVER...BY MID
TO LATE EVENING AFT 05Z FOG POTENTIAL WILL INCREASE. FRESH SNOW
COVER AND CLEARING SKIES ALONG WITH AMPLE MOISTURE IN THE BOUNDARY
LAYER MAY LEAD TO FOG. QUESTION ABOUT MOISTURE DEPOSITION OR IF IT
REMAINS SUSPENDED. WINDS WILL REMAIN IN THE 7 TO 8KT RANGE...SO THIS
MAY HELP THE AIRMASS REMAIN MIXED AS THE ENTIRE COLUMN COOLS TO
SATURATION. THOUGH CONFIDENCE LOW...MAY NEED TO UPDATE FOR LIFR FOG
AND OR CIGS LATER THIS EVENING IF TRENDS FOR THICK FOG ARE
CONFIRMED. THEN...PERIOD OF MOST CONCERN WOULD SHIFT TO 10-15Z
SUNDAY MORNING. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ADAMS-CASS.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARKE-
DECATUR-JASPER-LUCAS-MAHASKA-MARION-POWESHIEK-RINGGOLD-TAYLOR-
WARREN.
&&
$$
SHORT TERM...SMALL/REV
LONG TERM...AWB
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
519 PM CST SAT FEB 4 2012
.UPDATE 05/00Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
PRIMARY CONCERNS REMAIN SNOW TRENDS. RADAR AND SATELLITE
OBSERVATIONS INDICATE THAT PRECIP INTENSITY IS BEGINNING TO WANE
WITH TOPS WARMING AND ECHOES DIMINISHING. MODELS CONFIRM THIS AS
WELL WITH 18Z RUC UVM AND MOISTURE BOTH DECREASING IN DENDRITIC
GROWTH ZONE AROUND H6/H5 OR 300K ISENT SURFACE. THIS THINKING HAS
LEAD TO CATEGORICAL POPS WITH LITTLE ADDITIONAL ACCUMULATION THROUGH
00Z...FOLLOWED BY FURTHER DECREASE IN POPS AND NORTH TO SOUTH
COVERAGE LATER THIS EVENING. MOST LOCAL VISIBILITIES ARE NOW 1SM OR
GREATER. HEADLINES WERE TRIMMED TO 06Z THIS AFTERNOON AND COULD
VERY WELL NEED TO BE CANCELLED EVEN EARLIER THIS EVENING IF TRENDS
CONTINUE.
NEXT CONCERN TURNS TO CONDITIONS OVERNIGHT. VERY SHALLOW STRATUS
AND FOG WAS MAKING HEADWAY SOUTH EARLIER THIS AFTERNOON BUT THAT HAS
NOW ERODED. LOW LEVEL WINDS WILL LIKELY BE JUST STRONG ENOUGH TO
PRECLUDE WIDESPREAD DENSE FOG. HOWEVER 21Z SURFACE ANALYSIS SHOWS
LACK OF MUCH DRYING UPSTREAM SO HAVE MENTIONED PATCHY FOG FOR A
START IN CASE THIS MOISTURE AREA DOES INDEED FILL BACK IN AGAIN.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LOW WILL HAVE PUSHED FURTHER EAST FOR BEGINNING OF PERIOD...WITH
HIGH PRESSURE PUSHING IN. HAVE INCLUDED MENTION FOR FOG ACROSS THE
NORTH EARLY SUNDAY MORNING...AND SHOULD LIFT BY LATE MORNING.
COULD AGAIN SEE FOG EARLY MONDAY...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE MENTION ATTM. LOW OVER ROCKIES WILL DEEPEN...AND REMAIN
OVER ROCKIES THROUGH TUESDAY WITH SPLIT FLOW OVER REGION.
TEMPERATURES WILL WARM INTO MONDAY WITH WAA AND WEAK RIDGING OVER
IOWA.
STRONG WAVE WILL PUSH LOW OUT OF ROCKIES TUESDAY. THIS WILL BRING
A CHANCE FOR PRECIPITATION ACROSS IOWA. MODELS DO NOT HAVE GOOD RUN-
TO-RUN CONSISTENCY WITH TRACK OF LOW...BUT ARE BEGINNING TO PULL IT
FURTHER NORTH. HAVE INCLUDED SLIGHT CHANCE FOR PRECIPITATION
ACROSS SOUTHERN IOWA FOR TUESDAY INTO WEDNESDAY. WILL LIKELY SEE
RAIN CHANGING OVER TO SNOW. CURRENTLY...LIFT IS A BIT
LACKING...AND PRECIPITATION WILL LIKELY BE LIGHT.
BEHIND LOW...ANOTHER FRONTAL BOUNDARY WILL PUSH DOWN FROM CANADA.
ATTM APPEARS FROPA WILL BE DRY. MUCH COLDER AIR WILL WORK IN
BEHIND FRONT AND TEMPERATURES WILL GRADUALLY COOL TOWARDS END OF
PERIOD.
&&
.AVIATION...05/00Z
SYSTEM BEGINNING TO WEAKEN AS DEF ZONE LOSING SUPPORT FROM MAIN
UPPER LEVEL LOW PULLING OFF THE THE SOUTHEAST OF IA THIS EVENING.
CONSEQUENTLY...CIGS AND VSBYS WILL CONTINUE TO IMPROVE FOR THE SHORT
TERM WITH GENERALLY VFR FOR A SHORT PERIOD OF TIME. HOWEVER...BY MID
TO LATE EVENING AFT 05Z FOG POTENTIAL WILL INCREASE. FRESH SNOW
COVER AND CLEARING SKIES ALONG WITH AMPLE MOISTURE IN THE BOUNDARY
LAYER MAY LEAD TO FOG. QUESTION ABOUT MOISTURE DEPOSITION OR IF IT
REMAINS SUSPENDED. WINDS WILL REMAIN IN THE 7 TO 8KT RANGE...SO THIS
MAY HELP THE AIRMASS REMAIN MIXED AS THE ENTIRE COLUMN COOLS TO
SATURATION. THOUGH CONFIDENCE LOW...MAY NEED TO UPDATE FOR LIFR FOG
AND OR CIGS LATER THIS EVENING IF TRENDS FOR THICK FOG ARE
CONFIRMED. THEN...PERIOD OF MOST CONCERN WOULD SHIFT TO 10-15Z
SUNDAY MORNING. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL MIDNIGHT CST TONIGHT FOR ADAIR-ADAMS-
AUDUBON-CASS-DALLAS-GUTHRIE-MADISON-POLK-UNION.
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR CLARKE-
DECATUR-JASPER-LUCAS-MAHASKA-MARION-POWESHIEK-RINGGOLD-TAYLOR-
WARREN.
&&
$$
SHORT TERM...SMALL
LONG TERM...AWB
AVIATION...REV
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 TOPEKA KS
606 PM CST SAT FEB 4 2012
...UPDATE TO AVIATION...
&&
.AVIATION...
LIGHT DRIZZLE AND LIGHT SNOW CONTINUE INTO THE EARLY MORNING HOURS
AT THE TAF SITES AS THE CLOUD DECK CONTINUES TO LOWER TO LIFR.
BROUGHT CIGS BACK ABOVE 1000FT AGL AFTER SUNRISE AND EXPECT CLOUDS
TO BREAK UP QUICK AFTER THAT.
&&
.PREV DISCUSSION...
/ISSUED 308 PM CST SAT FEB 4 2012/
SHORT RANGE FORECAST (TONIGHT THROUGH SUNDAY)...
UPPER LEVEL LOW PRESSURE SYSTEM IS CURRENTLY CENTERED ROUGHLY OVER
KFNB AS OF 20Z PER WATER VAPOR IMAGERY AND RUC UPPER LEVEL ANALYSIS.
THE TROUGH HAS BEEN STEADY STATE REGARDING INTENSITY THROUGHOUT THE
DAY...MEANING IT HAS NOT UNDERGONE SIGNIFICANT STRENGTHENING OR
WEAKENING. WATER VAPOR IMAGERY ALSO INDICATING A SLOT OF DRY AIR
STRETCHING FROM SOUTH CENTRAL IOWA SOUTHWESTWARD TO THE
OKLAHOMA/TEXAS PANHANDLES. THIS DRY SLOT HAS CAUSED THE MID LEVELS
TO BECOME RATHER DRY...WHICH HAS CREATED A DRIZZLY AFTERNOON ACROSS
MUCH OF NORTHEAST KANSAS..ESPECIALLY EAST OF A MARYSVILLE TO TO
ABILENE LINE. WEST AND NORTH OF THAT LINE VERY LIGHT SNOW SHOWERS
ARE PERSISTING AS THE UPPER LOW RESIDES OVER THE AREA. WITH THE LACK
OF ANY APPRECIABLE MID LEVEL FRONTOGENESIS AND MEAGER OVERALL LIFT
INDICATED BY OMEGA VALUES PROGGED TO BE IN THE -2 TO -4 MICROBAR/SEC
RANGE...DO NOT EXPECT MUCH MORE SNOW TO FALL ACROSS ANY OF THE
FORECAST AREA DURING THE REMAINDER OF THE AFTERNOON AND EVENING.
ACROSS FAR EASTERN KANSAS...EXPECT CLOUDY CONDITIONS TO REMAIN WITH
PERIODS OF LIGHT RAIN AND PATCHY DRIZZLE. LATER THIS AFTERNOON
FORECAST MODELS HINT AT SOME DEEPER MOISTENING OF THE ATMOSPHERIC
COLUMN WHICH COULD ALLOW FOR SOME LIGHT SNOW SHOWERS ALONG THE
INTERSTATE 70 CORRIDOR LATER TONIGHT. SNOW AMOUNTS WILL BE PRETTY
MEAGER WITH ONLY A TENTH OR TWO OF AN INCH OF SNOW. EXPECT PRECIP TO
COME TO A GRADUAL END BY LATE SATURDAY NIGHT INTO EARLY SUNDAY
MORNING AS THE UPPER SYSTEM COMPLETELY MOVES OUT OF THE AREA. EXPECT
SKIES TO ALSO GRADUALLY CLEAR OVERNIGHT AND THROUGHOUT THE DAY ON
SUNDAY. MADE VERY FEW CHANGES TO TEMPERATURES FOR THE OVERNIGHT
HOURS SATURDAY AND DAYTIME PERIOD ON SUNDAY...BUT DID LOWER TEMPS ON
THE ORDER OF 3 TO 5 DEGREES WHERE THE MOST SNOW FELL...NAMELY ACROSS
CLOUD...REPUBLIC...WASHINGTON...AND MARSHALL COUNTIES.
JL
MONDAY AND MONDAY NIGHT...SURFACE HIGH PRESSURE AND AMPLIFYING
SOUTHERN RIDGE WILL KEEP CONDITIONS TRANQUIL ACROSS THE PLAINS
MONDAY AND MONDAY EVENING. SOUTHWESTERLY FLOW WILL RETURN TO THE
REGION ON MONDAY ON THE WEST SIDE OF THE SURFACE RIDGE ALONG WITH
WEAK WAA. MODELS PROG CANADIAN TROF TO SWEEP CUTOFF LOW OVER THE
WASATCH RANGE MONDAY AFTERNOON...AND OUT ONTO THE PLAINS BY MONDAY
NIGHT. AFTERNOON HIGHS ON MONDAY WILL BE SLIGHTLY ABOVE NORMAL IN
THE MID TO UPPER 40`S DUE TO THE WEAK WAA. THE NORTHWESTERN
COUNTIES WILL LIKELY REMAIN IN THE 30`S WITH THE SNOW COVER.
TUESDAY AND TUESDAY NIGHT...COLD FRONT EXPECTED TO SWEEP THROUGH THE
CWA TUESDAY MORNING. MID LEVEL MOISTURE ADVECTS INTO THE AREA FROM
THE WEST...WHERE LOW LEVEL MOISTURE ADVECTS IN WITH THE COLD AIR
BEHIND THE 850MB FRONT MID DAY TUESDAY. BUMPED UP POPS A BIT
TUESDAY MORNING AND AFTERNOON WITH SLOWLY GROWING CONFIDENCE THAT
PRECIP WILL OCCUR ON TUESDAY. ECMWF AND GFS HAD DIVERGED WITH THE
AREAS OF GREATEST QPF. GFS WAS MUCH FURTHER NORTH AND AWAY FROM BEST QG
FORCING SUPPORT OVER SOUTHERN KANSAS AND OKLAHOMA. ECMWF HAD BEEN
IN BETTER ALIGNMENT WITH THE QG FORCING. HOWEVER...LATEST ECMWF
ALIGNS IN BETTER AGREEMENT TO THE GFS THAN PREVIOUS RUNS...AND GIVEN
THE SIGNIFICANT PV ANOMALY PROGGED TO TRAVERSE EASTERN KANSAS
TUESDAY AFTERNOON AND EVENING...THINKING IS THAT ECMWF MAY BE ON
TRACK WITH HIGHER QPF AMOUNTS OVER EASTERN KANSAS THAN PREVIOUSLY
THOUGHT. FOR NOW...GIVEN INCONSISTENCY IN THE MODELS...BUMPED POPS
UP ONLY SLIGHTLY. NEXT QUESTION WILL BE PRECIP TYPE. FORECAST
SOUNDINGS INDICATE SFC TEMPS WILL BE CLOSE TO THE FREEZING MARK AT
THE SURFACE WITH DEPTHS OF ABOUT 400 FEET BEFORE SUB-ZERO
TEMPERATURES ARE REACHED ALOFT. HOWEVER...GFS DEPICTS 500MB DRY
SLOT NEAR THE ICE CRYSTAL GROWTH ZONE. IF ENOUGH DRY AIR WORKS INTO
THE GROWTH ZONE TO INHIBIT ICE CRYSTAL GROWTH...MAY ONLY SEE RAIN
INSTEAD OF ANY SNOW. LIFT IS NOT ABUNDANT WITH THIS SYSTEM...AND
MOST OF THE QG FORCING IS STILL PROGGED TO REMAIN SOUTH OF THE
CWA...BUT IF THE PV ANOMALY IS AS STRONG AS DEPICTED COUPLED WITH
MODERATE MOISTURE ADVECTION...COULD POSSIBLY SEE A FEW HUNDREDTHS OF
AN INCH OF PRECIPITATION.
EXTENDED...SYSTEM EXITS TUESDAY NIGHT INTO WEDNESDAY WITH THE NEXT
WAVE EXPECTED WEDNESDAY EVENING. THIS SYSTEM ALSO PROGGED TO HAVE A
STRONG PV ANOMALY...AND ECMWF IS PICKING UP ON SOME PRECIPITATION
OVER NORTHEAST KANSAS. ATTM...LEFT THE EXTENDED DRY GIVEN THE
VARIABILITY IN THE MODEL RUNS AND THE FAIRLY DRY ATMOSPHERE IN PLACE
THURSDAY AFTERNOON. NEXT SYSTEM AND COLD FRONT EXPECTED THURSDAY EVENING AND
HIGH PRESSURE RETURNING ON FRIDAY AND SATURDAY. TEMPERATURES
WISE...SHOULD SEE HIGHS NEAR NORMAL WITH LOWS IN THE 20`S AND HIGHS
IN THE UPPER 30`S AND LOW 40`S. EXCEPTION WILL BE WITH THE SNOW
PACKED AREAS WITH HIGHS IN THE 30`S AND LOWS IN THE TEENS.
BYRNE
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS SHREVEPORT LA
942 PM CST SAT FEB 4 2012
.DISCUSSION...
THE COLD FRONT HAS WORKED ITS WAY OFFSHORE THE SE TX AND MUCH OF
THE SRN LA COAST THIS EVENING...ALTHOUGH THE DRIER AIR STILL LAGS
THE FRONT A WAYS FROM CNTRL LA INTO NCNTRL MS. THE REGIONAL
PROFILER DATA AND AREA VADS INDICATE THAT THE 925-850MB TROUGH
HAS JUST PUSHED THROUGH DEEP E TX/SRN SECTIONS OF NCNTRL LA...WITH
CONSIDERABLE LOW LEVEL DRYING EXPECTED OVERNIGHT AS THIS BOUNDARY
CONTINUES TO SLIP S. THE UPPER LOW ALOFT REMAINS SW THOUGH...WITH
A CONTINUED SUBTROPICAL FEED ONGOING ACROSS MUCH OF TX/LOWER MS
VALLEY. THIS HAS RESULTED IN CONSIDERABLE ELEVATED MOISTURE RIDING
ATOP THE DEEPENING POST-FRONTAL AIR MASS BUILDING S. MOSAIC RADAR
IMAGERY HAS BEEN DEPICTING THE AC FIELD OVER CNTRL TX THIS
EVENING...ALTHOUGH SFC OBS ARE HARD PRESSED TO INDICATE CIGS BELOW
12KFT. HOWEVER...THAT CHANGES FARTHER S ACROSS S TX...AS
POSTFRONTAL CONVECTION CONTINUES TO DEVELOP/SPREAD E ALONG A MID-
LEVEL CONVERGENCE ZONE...AHEAD OF A SHORTWAVE NOW ENTERING WCNTRL
OLD MX.
NOT EXPECTING THIS CONVECTION TO SPREAD NE INTO DEEP E TX TONIGHT
GIVEN THE DEEPENING DRY AIR...WITH THE LAST OF THE -RA/-DZ HAVING
EXITED WCNTRL LA ALONG THE LOWER TOLEDO BEND COUNTRY WITHIN THE
LAST COUPLE OF HOURS. THUS...HAVE REMOVED MENTION OF -RA TONIGHT
WITH THE EVENING UPDATE.
THE RUC IS REALLY THE ONLY MODEL THAT HANDLES THE POST-FRONTAL
STRATOCU OVER EXTREME NE TX/OK/AR WELL THIS EVENING...WITH A
TENDENCY OF GRADUALLY ERODING THIS FIELD AS IT DRIFTS S.
HOWEVER...WITH ELEVATED MOISTURE CONTINUING TO SPREAD E
OVERNIGHT...MOSTLY CLOUDY CONDITIONS SHOULD PERSIST. THIS CLOUD
COVER...AND NW WINDS...SHOULD ONLY RESULT IN A GRADUAL DOWNWARD
TREND IN TEMPS...WHICH THE FORECAST ALREADY REFLECTS.
THUS...LITTLE IF ANY CHANGES WERE NEEDED THIS EVENING.
ZONE UPDATE ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY.
15
&&
.AVIATION...
NORTHWEST WINDS 10 KTS TO PERSIST THROUGH THE TERMINAL FORECAST
PERIOD. MVFR CEILINGS POSSIBLE THROUGH 05/12Z ACROSS THE TXK/ELD
TERMINAL SITES AS POST-FRONTAL CLOUDS STREAM SOUTHEAST ACROSS
ARKANSAS. OTHERWISE...VFR CONDITIONS TO PREVAIL ON SUNDAY. /05/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 42 57 35 58 37 / 0 0 0 0 10
MLU 45 58 36 57 34 / 10 0 0 0 10
DEQ 35 53 30 57 30 / 0 0 0 0 10
TXK 38 53 33 56 33 / 0 0 0 0 10
ELD 40 56 33 57 31 / 0 0 0 0 10
TYR 38 54 35 55 38 / 0 0 0 0 10
GGG 39 55 35 56 36 / 0 0 0 0 10
LFK 43 56 37 58 38 / 10 10 10 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&
$$
15/05
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
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
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...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...UPDATED
NWS ST LOUIS MO
959 PM CST SAT FEB 4 2012
.UPDATE...
/955 PM CST SAT FEB 4 2012/
OUTSIDE OF AREAS OF DRIZZLE FROM CENTRAL INTO EAST CENTRAL
MO...PRECIP DEVELOPMENT AHEAD OF UPPER LOW HAD BEEN ALMOST NON-
EXISTANT IN OUR CWA. IN SPITE OF THIS...AM RELUCTANT TO TOTALLY
GIVE UP ON PRECIP TONIGHT. FOR THE UPDATE HAVE USED THE CURRENT
PRECIP OVER NW MO AND ITS RELATIONSHIP TO THE 7H LOW. FROM RUC AND
NAM...LOW IS FORECAST TO BE NEAR STL BY 12Z SUN...SO HAVE LAYED
OUT A NARROW BAND OF LIKELY POPS ALONG THE MO PORTION OF THE I-70
CORRIDOR FOR THE PREDAWN HOURS. AS FAR AS PTYPE IS
CONCERNED...HAVE PRETTY MUCH STAYED WITH THE TRENDS IN GOING
FORECAST. THIS MAY BE A BIT TOO FAST WITH THE RAIN TO SNOW
TRANSITION...BUT WITH THESE CLOSED UPPER SYSTEMS HAVE SEEN ENOUGH
INSTANCES WHERE FREEZING LEVELS RAPIDLY DROP THAT I DIDN`T WANT TO
GET TOO CUTE WITH THE TIMING. WOULD STILL THINK ANY ACCUMULATIONS
WOULD BE SPOTTY...AND UNDER AN INCH. UPDATE REFLECTING ABOVE
TRENDS HAS BEEN SENT.
TRUETT
&&
.SYNOPSIS...
/345 PM CST SAT FEB 4 2012/
WATER VAPOR LOOP SHOWS AN W-E ELONGATED MID LEVEL LO CENTER OVER THE
INTERFACE BETWEEN KS-NE-MO...SLOWLY OOZING E. A SPLIT FLOW PATTERN
OTHERWISE DOMINATES WRN NOAM WITH A REX BLOCK IN PLACE AND A MORE
UNIFIED FLOW OVER ERN NOAM. RADAR MOSAIC SHOWS DEFORMATION ZONE
PCPN ON THE NRN FLANK OF THE MID LEVEL FLOW AND EXTENDING EWD THRU
SRN-CNTRL IA AND NRN IL. FROM THE LO CENTER THRU CNTRL IA...THE AIR
IS COLD ENOUGH FOR THIS PCPN TO FALL AS SNOW...OTHERWISE FOR AREAS
FURTHER TO THE E...IT IS RAIN. 21Z MSAS DATA INDICATES TWO LO PRES
CENTERS...THE TRIPLE POINT OVER WRN KY AND AN OLD OCCLUDED CENTER IN
E CNTRL MO. CLOUDY SKIES ABOUND...EXCEPT IN SERN MO WHERE SUN HAS
BROKEN THRU...AND THIS HAS ALLOWED TEMPS TO WARM INTO THE MID-UPR
50S THERE. TEMPS HAVE OTHERWISE REMAINED IN THE 40S ELSEWHERE UNDER
THE THICK CLOUD CANOPY.
TES
&&
.DISCUSSION...
/345 PM CST SAT FEB 4 2012/
UPPER LOW WITH WEAK SFC LOW WILL DROP SEWD TGT AS AN UPPER LEVEL
RIDGE AND SFC RIDGE OVER THE NRN PLAINS SHIFTS SEWD. AREAS OF
DRIZZLE WILL CONTINUE THIS EVNG WHILE DEFORMATION ZONE
PRECIPITATION ACROSS SERN NEBRASKA AND SRN IA DROP SEWD THROUGH
NERN AND CNTRL MO AS WELL AS W CNTRL IL TGT. THE MODELS ARE FAIRLY
CONSISTENT WITH THE PLACEMENT OF THE PRECIPITATION FORECAST TGT AS
WELL AS THE WEAKENING TREND OR LESSENING OF THE QPF THROUGH TGT
INTO SUN MRNG. LOOKING AT MODEL PARTIAL THICKNESS FORECASTS AND
FORECAST SOUNDINGS THE P-TYPE SHOULD CHANGE FROM LIGHT RAIN TO
LIGHT SNOW IN COU AND UIN AROUND 06Z SUN OR SHORTLY AFTER...THEN
TRANSITION TO LIGHT SNOW JUST NW OF THE STL METRO AREA BY 12Z SUN
ALTHOUGH BY THIS TIME LITTLE IF ANY QPF WIL BE LEFT. WHILE MOST
AREAS N AND W OF THE STL METRO AREA WILL LIKELY ONLY RECEIVE A
LIGHT DUSTING OF SNOW... COULD NOT RULE OUT ONE HALF INCH TO NEAR
ONE INCH OF SNOW BETWEEN EDINA AND COLUMBIA MO TGT.
GKS
HOW WELL THE LO CENTER GETS PICKED UP BY A NRN STREAM SHORTWAVE
DROPPING THRU THE GREAT LAKES ON SUNDAY WILL PLAY A HUGE ROLE IN HOW
FAST THE LO CENTER MOVES THRU THE FA...WHICH WILL AFFECT HOW FAST
THE PCPN ENDS AND WHEN WE CLEAR OUT. MOST MODELS SAVE THE GFS ARE
BANKING ON THE NRN STREAM WAVE NOT PICKING UP THE OLD CNTRL CONUS LO
TOO WELL AND ARE THUS KEEPING PCPN AND CLOUDS AROUND FOR LONGER.
PCPN CURRENTLY TO OUR N IS BEING DRIVEN BY A MATURE WINTER STORM
WITH MAINLY MID LEVEL BROADSCALE FORCING AND FRONTOGENESIS...BUT
WITH SOME UPR LEVEL JET DYNAMICS TOO...TO GIVE US OUR DEFORMATION
ZONE PCPN. FRONTOGENESIS AND UPR JET DYNAMICS WILL BE THE FIRST TO
FADE LEAVING BEHIND A DILUTED STRENGTH AREA OF BROADSCALE LIFT THAT
WILL SURVIVE TO SUNDAY MORNING WHILE CONTINUING TO SLOWLY SLIDE
SEWD. WHILE MODEL SOUNDINGS SUGGEST WHAT SURVIVES WILL BE MAINLY
RAIN...EXPANDED THE AREA OF RAIN/SNOW MIX GIVEN THAT WET BULB ZERO
VALUES ARE FORECAST TO DIP JUST BELOW 1KFT AGL LEAVING LITTLE MARGIN
FOR ERROR. A FEW SPOTS MAY SEE A LIGHT DUSTING AS A RESULT...BUT
WITH SFC TEMPS ABOVE 32F IN MOST LOCATIONS...IT WILL BE DIFFICULT.
ANY PCPN THAT LINGERS MUCH PAST MID MORNING WILL BE RAIN AS TEMPS
BEGIN TO EDGE HIGHER. PREFERRED A MOS BLEND IN THE N WHERE THEY
WILL SEE SUN...BUT LEANED WITH THE COLDER MOS ELSEWHERE.
EVENING CLEARING OR CLEAR SKIES EXPECTED FOR SUNDAY NIGHT WITH HI
PRES SETTLING IN...SO AT LEAST MATCHED THE COLDEST MOS FOR MIN
TEMPS. QUIET WX THEN THRU TUESDAY MORNING WITH HI PRES IN CONTROL
AT THE SFC...BUT THIS WILL GIVE WAY TO A CDFNT LATER ON TUESDAY
WHERE INTRODUCED SOME CHCS FOR POST-FRONTAL PCPN...AS THE FRONT
ITSELF NOT STRONG ENOUGH TO KICK OFF PCPN BUT RATHER THIS WILL BE
FROM AN APPROACHING NEW CUTOFF LO FROM THE CNTRL ROCKIES. DEPENDING
ON HOW FAST THE COLD AIR RUSHES IN BEHIND THE FRONT AND HOW FAST THE
EWD TRANSLATION WILL BE WITH THAT CUTOFF LO...SOME OF THE PCPN COULD
BE SNOW IN THE FAR NRN FA...BUT MOST AREAS SHOULD SEE RAIN TUES AFTN
IF THEY GET ANYTHING AT ALL. THIS SYSTEM IS EXPECTED TO WEAKEN AS
IT MOVES E...VERY MUCH LIKE THE ONE WE ARE DEALING WITH NOW...BUT
TIMING ISSUES CONTINUE. EDGED POPS HIGHER FOR MID WEEK WITH THIS
SYSTEM BUT RELUCTANT TO DO MUCH MORE THAN THAT UNTIL WE GET BETTER
CONSENSUS ON TIMING AND TRACK. MORE POTENT ECMWF SUGGESTS POTENTIAL
FOR SOME ACCUMULATING SNOW...BUT IS AN OUTLIER AT THIS TIME.
MEDIUM RANGE HAS COME INTO BETTER AGREEMENT BETWEEN MODELS WITH A
PATTERN CHANGE IN THE AIR...AS A HI-AMPLITUDE BLOCKING RIDGE SETS UP
OVER WRN NOAM ALLOWING A DEEP TROF TO DEVELOP IN THE E. SOME
DISAGREEMENT ON HOW FAR S THIS TROF WILL PLUNGE...BUT THERE IS
AGREEMENT IN THAT IT WILL LAST THRU LATE WEEK AND INTO NEXT
WEEKEND. SOMETHING WE HAVE RARELY SEEN THIS WINTER. TEMPS
GENERALLY AVERAGE TO BELOW AVERAGE THIS PERIOD...WAITING ON MORE
AGRESSIVELY GOING LOWER...WITH FEW PCPN CHCS OUTSIDE OF THE MID WEEK
SYSTEM.
TES
&&
.AVIATION...
/516 PM CST SAT FEB 4 2012/
NOT TOO MANY CHANGES FROM THE PREV TAF. BELIEVE CURRENT CONDITIONS
WILL BE THE RULE AT TERMINALS THRU MUCH OF THE NIGHT. EXCEPTION
WILL BE COU WHERE ONGOING SN ACROSS SRN IA IS EXPECTED TO DROP S
AND IMPACT COU LATE TONIGHT. RA IS ALSO EXPECTED AT UIN LATER THIS
EVE...BUT IS CURRENTLY NOT ANTICIPATED TO CHANGE TO SN. HAVE
SLOWED CLEARING AT TERMINALS AS LATEST OBS CONTINUE TO BE SLOWER
THAN GUIDANCE. BEHIND THIS SYSTEM...SKIES SHUD BE MOSTLY CLEAR
WITH NLY WINDS. HOWEVER...HAVE LOW CONFIDENCE IN TIMING OF
CLEARING IN CURRENT TAF AND MAY NEED TO BE PUSHED BACK WITH LATER
UPDATES.
SPECIFICS FOR KSTL...NOT TOO MANY CHANGES FROM THE PREV TAF. BELIEVE
CURRENT CONDITIONS WILL BE THE RULE AT TERMINAL THRU MUCH OF THE
NIGHT. ASIDE FROM DZ THIS EVE...DO NOT ANTICIPATE PRECIP WHICH
SHUD BE W OF TERMINAL OVERNIGHT. HAVE SLOWED CLEARING AS LATEST
OBS CONTINUE TO BE SLOWER THAN GUIDANCE. BEHIND THIS
SYSTEM...SKIES SHUD BE MOSTLY CLEAR WITH NLY WINDS. HOWEVER...HAVE
LOW CONFIDENCE IN TIMING OF CLEARING IN CURRENT TAF AND MAY NEED
TO BE PUSHED BACK WITH LATER UPDATES.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
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...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 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
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 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 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 NEWPORT/MOREHEAD CITY NC
638 PM EST SAT FEB 4 2012
.SYNOPSIS...
A COLD FRONT WILL SAG SLOWLY SOUTH INTO THE AREA TONIGHT AND
SUNDAY MOVING SOUTH OF THE AREA BY SUNDAY AFTERNOON. HIGH
PRESSURE WILL BUILD IN FROM THE NORTH SUNDAY NIGHT AND MONDAY.
LOW PRESSURE WILL LIFT NORTHEAST OFFSHORE OF THE COAST MONDAY
NIGHT AND TUESDAY...FOLLOWED BY HIGH PRESSURE WEDNESDAY. ANOTHER
LOW PRESSURE PRESSURE SYSTEM LIFTS NORTHEAST OFFSHORE OF THE COAST
ON THURSDAY.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 630 PM SATURDAY...FRONTAL BOUNDARY WILL CONTINUE TO SLOWLY
SAG SOUTH OVERNIGHT AS A WAVE LOW PRESSURE RIDES ALONG THE FRONT
ACROSS THE CWA. SOME LIGHT SHOWERS AFFECTING THE NORTHERN CWA
CURRENTLY. ISENTROPIC LIFT WILL INCREASE OVER THE NEXT SEVERAL
HOURS WITH ADDITIONAL PRECIPITATION ARRIVING OVER THE AREA AFTER
MIDNIGHT AND INTENSIFYING TOWARD MORNING. HAVE MADE ONLY MINOR
CHANGES TO CURRENT FORECAST.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH 6 PM SUNDAY/...
THE FRONT AND ASSOCD STEADIER RAIN WILL PUSH SLOWLY SOUTH THRU THE
AREA SUNDAY MORNING. PCPN WILL TAPER OFF AND BECOME MORE SPOTTY
DURING THE AFTN BUT NOT EXPECTING MUCH IF ANY CLEARING AS LOW
LEVEL MOISTURE REMAINS STUCK UNDER AN INVERSION. ONLY SMALL DIURNAL
TEMPERATURE RISES WILL BE A RESULT OF THE LOW CLOUD COVER AND
PCPN WITH HIGHS LOWER 50S NORTH TO UPPER 50S/ARND 60 SOUTH.
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
AS OF 245 PM SAT...COLD FRONT AND SURFACE LOW WILL BE OFF CAPE FEAR
SUN NIGHT WITH PRECIP DIMINISHING FROM NW TO SE LATE. SURFACE HIGH
BRIEFLY NOSES SOUTH ACROSS THE REGION MON MORNING WITH ONLY SLIGHT
CHANCE POPS OFF THE COAST THROUGH ABOUT 18Z. MINOR DIFFERENCES
BETWEEN 12Z GFS AND 12Z ECMWF WITH THE ECMWF HAVING A STRONGER
SURFACE LOW THAT TRACKS NE ALONG THE COAST RATHER THAN E WELL OFF
THE COAST WITH THE GFS. THE ECMWF ALSO APPEARS ABOUT 12 HOURS LATER
THAN THE GFS. A SECONDARY SURFACE LOW WILL DEVELOP OFF CAPE FEAR AND
PUSH NORTHEAST LATE MON INTO EARLY TUES AS A STRONG UPPER LEVEL LOW
AND VORTMAX PUSH EAST THROUGH THE REGION. FLOW BECOMES ZONAL ALOFT
WITH SURFACE RIDGE ACROSS THE OHIO RIVER VALLEY MOVING SE ACROSS
EASTERN NC.
FORECAST WED INTO EARLY THURS WILL REMAIN MOSTLY DRY BUT BECOMES
TRICKY GIVEN THE LOCATION OF A SHORTWAVE PROGGED TO CROSS NORTH OF
THE REGION AND A STALLED FRONTAL BOUNDARY WITH MOIST TROPICAL
AIRMASS SOUTH OF THE REGION. WEAK SURFACE RIDGING SHOULD REMAIN IN
CONTROL WED INTO THURS BUT A MORE SOUTHWARD TRAJECTORY OF THE
NORTHERN STREAM SHORTWAVE...OR A MORE NORTHERN MOVEMENT OF THE
SOUTHERN STREAM FRONTAL BOUNDARY...AND THE REGION COULD SEE
MEASURABLE PRECIP. GENERALLY FOLLOWED A MODEL COMPROMISE THROUGH THE
MEDIUM RANGE THEN LEANED TO THE 00Z/12Z ECMWF FOR THE EXTENDED
RANGE. BY LATE WEEK A STRONG COASTAL LOW WILL DEVELOP AND PUSH
NORTHEAST OFF THE CAROLINA COAST. HAVE MAINTAINED SLIGHT CHANCE POPS
THURS AFTERNOON INTO THURS NIGHT WITH A DRY FORECAST FRI.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
SHORT TERM /THROUGH SUNDAY/
AS OF 635 PM SATURDAY...CURRENT VFR CEILINGS WILL LOWER TO IFR BY
ABOUT 03Z AS PRECIPITATION GRADUALLY INCREASES FROM THE NORTH AND
WEST WITH INCREASED ISENTROPIC LIFT. CEILINGS WILL LIKELY STAY
LOCKED IN AT IFR STATUS THRU MUCH OF THE DAY ON SUNDAY.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 250 PM SAT...WEAK COLD AIR DAMMING WILL SETUP SUN NIGHT AS
COLD FRONT WILL BE SOUTH OF THE TAF SITES WITH HIGH PRESSURE NOSING
SOUTH ACROSS THE REGION. A SURFACE LOW IS PROJECTED TO CROSS THE
REGION FROM SW TO NE MON WITH SHOWERS...WITH POSSIBLE MVFR/IFR
CONDITIONS IN LOWERED CEILINGS AND VISIBILITIES. VFR CONDITIONS
LIKELY TUES INTO WED AS HIGH PRESSURE MIGRATES SOUTHEAST OVER THE
AREA.
&&
.MARINE...
SHORT TERM /THROUGH SUNDAY/...
AS OF 635 PM SATURDAY...WINDS CURRENTLY RATHER LIGHT FROM THE
SSE/S ACROSS THE COASTAL WATERS AND SOUNDS. LATEST RUC13 INDICATES
WINDS SHOULD INCREASE FROM SOUTHWEST TO NORTHEAST OVER THE NEXT 2
TO 4 HOURS WITH 20 TO 25 KNOTS LIKELY OVER PORTIONS OF THE MARINE
AREA BY MIDNIGHT. SEAS CURRENTLY 3 TO 5 FEET AND WILL LIKELY
INCREASE AS WINDS RAMP UP THRU THE EVENING. NO CHANGES TO THE
CURRENT SMALL CRAFT ADVISORIES.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
AS OF 3 AM SAT...SIGNIFICANT UNCERTAINTY CONTINUES WITH THE FORECAST
AS MODELS ARE HANDLING SEVERAL SYSTEMS TRACKING ACROSS THE REGION
DIFFERENTLY. BY SUN NIGHT EXPECT THE COLD FRONT TO BE SOUTH OF THE
AREA WITH HIGH PRES BUILDING IN FROM THE N BRINGING MODERATE NLY
FLOW AROUND 15-25 KT AND SEAS AS HIGH AS 7 FT. CONDITIONS IMPROVE
LATE SUN NIGHT AND MON AND EXPECT CONDITIONS TO DROP BELOW SCA
CRITERIA DURING THE DAY MON. A LOW PRES SYSTEM IS THEN PROGGED TO
TRACK ALONG THE COAST EARLY NEXT WEEK BUT MODELS HAVE BEEN
STRUGGLING WITH THE TIMING AND STRENGTH OF THIS SYSTEM WITH FASTER
MODEL TRACKING THE LOW ACROSS THE REGION MON AND SLOWER SOLUTIONS
LATE MON NIGHT INTO EARLY TUE. COULD SEE A BRIEF PERIOD OF MINIMAL
SCA CONDITIONS WITH THIS SYSTEM IF STRONGER MODEL SOLUTIONS VERIFY
BUT WILL KEEP JUST BELOW ATTM. HIGH PRES IS THEN PROGGED TO BUILD
INTO THE REGION LATE TUE THROUGH WED BRINGING MODERATE NLY FLOW BUT
REMAIN BELOW SCA CRITERIA.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM SUNDAY TO 1 AM EST MONDAY FOR
AMZ152-154.
SMALL CRAFT ADVISORY FROM 1 AM TO 7 PM EST SUNDAY FOR AMZ156-
158.
SMALL CRAFT ADVISORY FROM 3 PM SUNDAY TO 1 AM EST MONDAY FOR
AMZ150.
&&
$$
SYNOPSIS...BTC
NEAR TERM...CTC
SHORT TERM...BTC
LONG TERM...DAG
AVIATION...CTC/DAG
MARINE...CTC/DAG
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
830 PM CST SAT FEB 4 2012
.DISCUSSION...
UPDATED GRIDS TO REFLECT CURRENT TRENDS OF STRATUS DECK MOVING
SOUTHWARD OVER CWA...AS WELL AS FOG FORMING EARLIER THAN FORECAST.
LIGHT NORTHLY FLOW AIDING IN ITS MOVEMENT SO NO REASON WHY IT WON`T
CONTINUE TO MOVE AOUTH. RUC MODEL ALSO BACKS CURRENT TREND. MOVED
CLOUD DECK AS FAR SOUTH AS KSUX AND THEN SLOWLY DISSIPATING DECK
POST SUNRISE ON SUNDAY. AS RESULT...I ALSO ADJUSTED A FEW LOW
TEMPERATURE FORECASTS AT THE SAME TIME.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
AREA OF IFR STRATUS REMAINS THROUGH NORTHEASTERN SOUTH DAKOTA
NORTHWARD INTO EASTERN NORTH DAKOTA EARLY THIS EVENING...AND SHOWING
SIGNS OF DROPPING SOUTHWARD ON A NORTHERLY/NORTHWESTERLY LOW LEVEL
FLOW. THINK THIS WILL PERSIST OVER KHON THROUGH THE NIGHT...BUT MORE
UNCERTAIN IS HOW FAR SOUTH THE STRATUS WILL MAKE IT. RUC MODEL
GUIDANCE INDICATING THAT IT MAY MAKE IT TO THE I29 CORRIDOR BY LATER
TONIGHT...SO INCLUDED IN KFSD TAF...THOUGH CONFIDENCE IS LOW. WITH
LIGHT WINDS TONIGHT...MAY ALSO SEE AREAS OF MVFR FOG DEVELOP ACROSS
PORTIONS OF THE REGION.
&&
.PREV DISCUSSION.../ISSUED AT 315 PM CST/
WITH LAST OF THE CLOUDS FROM THE SOUTHERN SYSTEM MOVING SOUTHEAST OF
AREA THIS EVENING...PROBLEM WILL BE THE POTENTIAL REDEVELOPMENT OF
STRATUS AND FOG OVER THE AREA TONIGHT AS WINDS STEADILY BECOME
LIGHT. SEEMINGLY AMPLE LOW LEVEL MOISTURE WOULD SEEM TO POINT TO
REDEVELOPMENT BUT SUBSIDENCE/WARMING/DRYING ABOVE THE SURFACE IS
BECOMING MORE EVIDENT ALL THE TIME...SUCH AS IN THE LOWERED
DEWPOINTS AT PQN AND FSD WITH THE HEATING. ANY LOW LEVEL MOISTURE
WILL TEND TO BECOME SHALLOWER WITH TIME AND THINK THIS WILL BE
ENOUGH TO KEEP THE STRATUS FROM REDEVELOPING. WILL ALLOW FOR SOME
AREAS OF FOG TO DEVELOP BUT IT WILL HAVE TO BE SHALLOW. WOULD NOT BE
SURPRISED TO SEE IT ABSENT BUT FOG IN THESE CASES DOES NOT NEED VERY
DEEP MOISTURE AND COOLING TO DEVELOP. WILL RESTRICT IT TO LATE
TONIGHT. TEMPERATURES NOT MUCH OF A PROBLEM...SHOULD COOL GENERALLY
INTO THE LOWER 20S.
IF THERE IS ANY FOG IT SHOULD GO QUICKLY SUNDAY MORNING AND LEAVE A
PRETTY SUNNY DAY WITH TEMPERATURES REBOUNDING INTO THE 40S
EVERYWHERE...NOT JUST HERE AT FSD. FAIRLY LIGHT WINDS SHOULD SHOW A
SLOW TREND FROM NORTHWEST TO WEST AND SOUTHWEST. / WILLIAMS
UNORGANIZED SPLIT FLOW WILL DOMINATE FOR MUCH OF THE NEXT WEEK...
WITH LITTLE IN THE WAY OF PRECIP CHANCES SEEN FOR OUR AREA. SOUTHERN
AND NORTHERN STREAMS ATTEMPT TO PHASE LATE MONDAY NIGHT/TUESDAY WITH
MOST MODELS SPITTING OUT SOME VERY LIGHT QPF NEAR AND SOUTH OF THE
MISSOURI VALLEY. SOUNDINGS FOR OUR AREA SHOW DEEP DRY LAYER BENEATH
THE INCREASING MID CLOUD DECK SO WILL LEAVE FORECAST DRY FOR NOW...
THOUGH FLURRIES NOT OUT OF THE QUESTION IN SOUTHERN AREAS. TIMING OF
COLD FRONT ON MONDAY SEEMS TO HAVE SLOWED A BIT FROM PREVIOUS...SO
HAVE BUMPED TEMPS A FEW DEGREES ALONG/SOUTH OF I-90. POTENTIAL FOR
WARMING IN FAR SOUTHERN AREAS A LITTLE TRICKY...AS LOW LEVEL FLOW
AHEAD OF THE FRONT WILL BE COMING OFF FRESH DEEP SNOWPACK...BUT EVEN
ISOTHERMAL FROM 925MB WOULD YIELD LOWER 40S AND A FEW DEGREES ABOVE
THAT SHOULD BE ACHIEVABLE WITH MIXING AHEAD OF THE FRONT. BREEZY
CONDITIONS IN THE COLD ADVECTION ALONG WITH INCREASING CLOUDS MONDAY
NIGHT SHOULD HOLD TEMPERATURES UP IN THE UPPER TEENS TO MID 20S...
WITH LITTLE RECOVERY EXPECTED DESPITE CLEARING ON TUESDAY. LARGER
DIURNAL RANGE EXPECTED TUESDAY NIGHT/WEDNESDAY. SURFACE RIDGE
TUESDAY NIGHT WILL ALLOW FOR GOOD RADIATIVE COOLING...ESPECIALLY
WEST WHERE CLOUDS ARE MORE LIKELY TO CLEAR. SOUTH-SOUTHWEST FLOW
COMING OFF SNOWPACK ON WEDNESDAY WILL LIKELY TEMPER WARMING SOME...
BUT READINGS NEAR TO JUST ABOVE FREEZING OVER OUR BARE GROUND SEEM
REASONABLE.
TIMING OF ARCTIC PUSH...WITH 850MB TEMPERATURES IN THE TEENS BELOW
ZERO...LOOKS TO BE ON TARGET FOR THURSDAY/THURSDAY NIGHT TIME FRAME.
HOWEVER DISCREPANCIES ABOUND IN HOW FAR WEST THE COLD AIR WILL GET
AND HOW LONG IT WILL STICK AROUND...MAKING HIGHS FOR FRIDAY THE
BIGGEST QUESTION OF THE LONGER RANGE. 00Z SATURDAY 850MB TEMPS VARY
BY 10 DEGREES ACROSS VARIOUS DETERMINISTIC MODELS...AND BY CLOSER TO
20 DEGREES AMONG THE 12Z GFS ENSEMBLE MEMBERS...LEAVING QUITE A BIT
OF ROOM FOR LARGE ERRORS IN THIS PERIOD. HOWEVER...GIVEN CONTINUED
LACK OF SNOW AND RELATIVELY DRY AIRMASS IN WAKE OF SURFACE RIDGE
WHICH MOVES THROUGH THURSDAY NIGHT...WILL ERR TOWARD WARMER SIDE OF
GUIDANCE SPECTRUM. A LITTLE MORE WARMING EXPECTED FOR SATURDAY AS
MODELS SHOW BETTER CONSENSUS IN SHIFTING THE COLDER AIR OFF TO THE
EAST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
315 PM CST SAT FEB 4 2012
.DISCUSSION.../ISSUED AT 315 PM CST/
WITH LAST OF THE CLOUDS FROM THE SOUTHERN SYSTEM MOVING SOUTHEAST OF
AREA THIS EVENING...PROBLEM WILL BE THE POTENTIAL REDEVELOPMENT OF
STRATUS AND FOG OVER THE AREA TONIGHT AS WINDS STEADILY BECOME
LIGHT. SEEMINGLY AMPLE LOW LEVEL MOISTURE WOULD SEEM TO POINT TO
REDEVELOPMENT BUT SUBSIDENCE/WARMING/DRYING ABOVE THE SURFACE IS
BECOMING MORE EVIDENT ALL THE TIME...SUCH AS IN THE LOWERED
DEWPOINTS AT PQN AND FSD WITH THE HEATING. ANY LOW LEVEL MOISTURE
WILL TEND TO BECOME SHALLOWER WITH TIME AND THINK THIS WILL BE
ENOUGH TO KEEP THE STRATUS FROM REDEVELOPING. WILL ALLOW FOR SOME
AREAS OF FOG TO DEVELOP BUT IT WILL HAVE TO BE SHALLOW. WOULD NOT BE
SURPRISED TO SEE IT ABSENT BUT FOG IN THESE CASES DOES NOT NEED VERY
DEEP MOISTURE AND COOLING TO DEVELOP. WILL RESTRICT IT TO LATE
TONIGHT. TEMPERATURES NOT MUCH OF A PROBLEM...SHOULD COOL GENERALLY
INTO THE LOWER 20S.
IF THERE IS ANY FOG IT SHOULD GO QUICKLY SUNDAY MORNING AND LEAVE A
PRETTY SUNNY DAY WITH TEMPERATURES REBOUNDING INTO THE 40S
EVERYWHERE...NOT JUST HERE AT FSD. FAIRLY LIGHT WINDS SHOULD SHOW A
SLOW TREND FROM NORTHWEST TO WEST AND SOUTHWEST. / WILLIAMS
UNORGANIZED SPLIT FLOW WILL DOMINATE FOR MUCH OF THE NEXT WEEK...
WITH LITTLE IN THE WAY OF PRECIP CHANCES SEEN FOR OUR AREA. SOUTHERN
AND NORTHERN STREAMS ATTEMPT TO PHASE LATE MONDAY NIGHT/TUESDAY WITH
MOST MODELS SPITTING OUT SOME VERY LIGHT QPF NEAR AND SOUTH OF THE
MISSOURI VALLEY. SOUNDINGS FOR OUR AREA SHOW DEEP DRY LAYER BENEATH
THE INCREASING MID CLOUD DECK SO WILL LEAVE FORECAST DRY FOR NOW...
THOUGH FLURRIES NOT OUT OF THE QUESTION IN SOUTHERN AREAS. TIMING OF
COLD FRONT ON MONDAY SEEMS TO HAVE SLOWED A BIT FROM PREVIOUS...SO
HAVE BUMPED TEMPS A FEW DEGREES ALONG/SOUTH OF I-90. POTENTIAL FOR
WARMING IN FAR SOUTHERN AREAS A LITTLE TRICKY...AS LOW LEVEL FLOW
AHEAD OF THE FRONT WILL BE COMING OFF FRESH DEEP SNOWPACK...BUT EVEN
ISOTHERMAL FROM 925MB WOULD YIELD LOWER 40S AND A FEW DEGREES ABOVE
THAT SHOULD BE ACHIEVABLE WITH MIXING AHEAD OF THE FRONT. BREEZY
CONDITIONS IN THE COLD ADVECTION ALONG WITH INCREASING CLOUDS MONDAY
NIGHT SHOULD HOLD TEMPERATURES UP IN THE UPPER TEENS TO MID 20S...
WITH LITTLE RECOVERY EXPECTED DESPITE CLEARING ON TUESDAY. LARGER
DIURNAL RANGE EXPECTED TUESDAY NIGHT/WEDNESDAY. SURFACE RIDGE
TUESDAY NIGHT WILL ALLOW FOR GOOD RADIATIVE COOLING...ESPECIALLY
WEST WHERE CLOUDS ARE MORE LIKELY TO CLEAR. SOUTH-SOUTHWEST FLOW
COMING OFF SNOWPACK ON WEDNESDAY WILL LIKELY TEMPER WARMING SOME...
BUT READINGS NEAR TO JUST ABOVE FREEZING OVER OUR BARE GROUND SEEM
REASONABLE.
TIMING OF ARCTIC PUSH...WITH 850MB TEMPERATURES IN THE TEENS BELOW
ZERO...LOOKS TO BE ON TARGET FOR THURSDAY/THURSDAY NIGHT TIME FRAME.
HOWEVER DISCREPANCIES ABOUND IN HOW FAR WEST THE COLD AIR WILL GET
AND HOW LONG IT WILL STICK AROUND...MAKING HIGHS FOR FRIDAY THE
BIGGEST QUESTION OF THE LONGER RANGE. 00Z SATURDAY 850MB TEMPS VARY
BY 10 DEGREES ACROSS VARIOUS DETERMINISTIC MODELS...AND BY CLOSER TO
20 DEGREES AMONG THE 12Z GFS ENSEMBLE MEMBERS...LEAVING QUITE A BIT
OF ROOM FOR LARGE ERRORS IN THIS PERIOD. HOWEVER...GIVEN CONTINUED
LACK OF SNOW AND RELATIVELY DRY AIRMASS IN WAKE OF SURFACE RIDGE
WHICH MOVES THROUGH THURSDAY NIGHT...WILL ERR TOWARD WARMER SIDE OF
GUIDANCE SPECTRUM. A LITTLE MORE WARMING EXPECTED FOR SATURDAY AS
MODELS SHOW BETTER CONSENSUS IN SHIFTING THE COLDER AIR OFF TO THE
EAST.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
AREA OF IFR STRATUS REMAINS THROUGH NORTHEASTERN SOUTH DAKOTA
NORTHWARD INTO EASTERN NORTH DAKOTA EARLY THIS EVENING...AND SHOWING
SIGNS OF DROPPING SOUTHWARD ON A NORTHERLY/NORTHWESTERLY LOW LEVEL
FLOW. THINK THIS WILL PERSIST OVER KHON THROUGH THE NIGHT...BUT MORE
UNCERTAIN IS HOW FAR SOUTH THE STRATUS WILL MAKE IT. RUC MODEL
GUIDANCE INDICATING THAT IT MAY MAKE IT TO THE I29 CORRIDOR BY LATER
TONIGHT...SO INCLUDED IN KFSD TAF...THOUGH CONFIDENCE IS LOW. WITH
LIGHT WINDS TONIGHT...MAY ALSO SEE AREAS OF MVFR FOG DEVELOP ACROSS
PORTIONS OF THE REGION.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
555 PM CST SAT FEB 4 2012
.DISCUSSION.../ISSUED AT 315 PM CST/
WITH LAST OF THE CLOUDS FROM THE SOUTHERN SYSTEM MOVING SOUTHEAST OF
AREA THIS EVENING...PROBLEM WILL BE THE POTENTIAL REDEVELOPMENT OF
STRATUS AND FOG OVER THE AREA TONIGHT AS WINDS STEADILY BECOME
LIGHT. SEEMINGLY AMPLE LOW LEVEL MOISTURE WOULD SEEM TO POINT TO
REDEVELOPMENT BUT SUBSIDENCE/WARMING/DRYING ABOVE THE SURFACE IS
BECOMING MORE EVIDENT ALL THE TIME...SUCH AS IN THE LOWERED
DEWPOINTS AT PQN AND FSD WITH THE HEATING. ANY LOW LEVEL MOISTURE
WILL TEND TO BECOME SHALLOWER WITH TIME AND THINK THIS WILL BE
ENOUGH TO KEEP THE STRATUS FROM REDEVELOPING. WILL ALLOW FOR SOME
AREAS OF FOG TO DEVELOP BUT IT WILL HAVE TO BE SHALLOW. WOULD NOT BE
SURPRISED TO SEE IT ABSENT BUT FOG IN THESE CASES DOES NOT NEED VERY
DEEP MOISTURE AND COOLING TO DEVELOP. WILL RESTRICT IT TO LATE
TONIGHT. TEMPERATURES NOT MUCH OF A PROBLEM...SHOULD COOL GENERALLY
INTO THE LOWER 20S.
IF THERE IS ANY FOG IT SHOULD GO QUICKLY SUNDAY MORNING AND LEAVE A
PRETTY SUNNY DAY WITH TEMPERATURES REBOUNDING INTO THE 40S
EVERYWHERE...NOT JUST HERE AT FSD. FAIRLY LIGHT WINDS SHOULD SHOW A
SLOW TREND FROM NORTHWEST TO WEST AND SOUTHWEST. / WILLIAMS
UNORGANIZED SPLIT FLOW WILL DOMINATE FOR MUCH OF THE NEXT WEEK...
WITH LITTLE IN THE WAY OF PRECIP CHANCES SEEN FOR OUR AREA. SOUTHERN
AND NORTHERN STREAMS ATTEMPT TO PHASE LATE MONDAY NIGHT/TUESDAY WITH
MOST MODELS SPITTING OUT SOME VERY LIGHT QPF NEAR AND SOUTH OF THE
MISSOURI VALLEY. SOUNDINGS FOR OUR AREA SHOW DEEP DRY LAYER BENEATH
THE INCREASING MID CLOUD DECK SO WILL LEAVE FORECAST DRY FOR NOW...
THOUGH FLURRIES NOT OUT OF THE QUESTION IN SOUTHERN AREAS. TIMING OF
COLD FRONT ON MONDAY SEEMS TO HAVE SLOWED A BIT FROM PREVIOUS...SO
HAVE BUMPED TEMPS A FEW DEGREES ALONG/SOUTH OF I-90. POTENTIAL FOR
WARMING IN FAR SOUTHERN AREAS A LITTLE TRICKY...AS LOW LEVEL FLOW
AHEAD OF THE FRONT WILL BE COMING OFF FRESH DEEP SNOWPACK...BUT EVEN
ISOTHERMAL FROM 925MB WOULD YIELD LOWER 40S AND A FEW DEGREES ABOVE
THAT SHOULD BE ACHIEVABLE WITH MIXING AHEAD OF THE FRONT. BREEZY
CONDITIONS IN THE COLD ADVECTION ALONG WITH INCREASING CLOUDS MONDAY
NIGHT SHOULD HOLD TEMPERATURES UP IN THE UPPER TEENS TO MID 20S...
WITH LITTLE RECOVERY EXPECTED DESPITE CLEARING ON TUESDAY. LARGER
DIURNAL RANGE EXPECTED TUESDAY NIGHT/WEDNESDAY. SURFACE RIDGE
TUESDAY NIGHT WILL ALLOW FOR GOOD RADIATIVE COOLING...ESPECIALLY
WEST WHERE CLOUDS ARE MORE LIKELY TO CLEAR. SOUTH-SOUTHWEST FLOW
COMING OFF SNOWPACK ON WEDNESDAY WILL LIKELY TEMPER WARMING SOME...
BUT READINGS NEAR TO JUST ABOVE FREEZING OVER OUR BARE GROUND SEEM
REASONABLE.
TIMING OF ARCTIC PUSH...WITH 850MB TEMPERATURES IN THE TEENS BELOW
ZERO...LOOKS TO BE ON TARGET FOR THURSDAY/THURSDAY NIGHT TIME FRAME.
HOWEVER DISCREPANCIES ABOUND IN HOW FAR WEST THE COLD AIR WILL GET
AND HOW LONG IT WILL STICK AROUND...MAKING HIGHS FOR FRIDAY THE
BIGGEST QUESTION OF THE LONGER RANGE. 00Z SATURDAY 850MB TEMPS VARY
BY 10 DEGREES ACROSS VARIOUS DETERMINISTIC MODELS...AND BY CLOSER TO
20 DEGREES AMONG THE 12Z GFS ENSEMBLE MEMBERS...LEAVING QUITE A BIT
OF ROOM FOR LARGE ERRORS IN THIS PERIOD. HOWEVER...GIVEN CONTINUED
LACK OF SNOW AND RELATIVELY DRY AIRMASS IN WAKE OF SURFACE RIDGE
WHICH MOVES THROUGH THURSDAY NIGHT...WILL ERR TOWARD WARMER SIDE OF
GUIDANCE SPECTRUM. A LITTLE MORE WARMING EXPECTED FOR SATURDAY AS
MODELS SHOW BETTER CONSENSUS IN SHIFTING THE COLDER AIR OFF TO THE
EAST.
&&
.AVIATION.../FOR THE 00Z TAF ISSUANCE/
AREA OF IFR STRATUS REMAINS THROUGH NORTHEASTERN SOUTH DAKOTA
NORTHWARD INTO EASTERN NORTH DAKOTA EARLY THIS EVENING...AND SHOWING
SIGNS OF DROPPING SOUTHWARD ON A NORTHERLY/NORTHWESTERLY LOW LEVEL
FLOW. THINK THIS WILL PERSIST OVER KHON THROUGH THE NIGHT...BUT MORE
UNCERTAIN IS HOW FAR SOUTH THE STRATUS WILL MAKE IT. RUC MODEL
GUIDANCE INDICATING THAT IT MAY MAKE IT TO THE I29 CORRIDOR BY LATER
TONIGHT...SO INCLUDED IN KFSD TAF...THOUGH CONFIDENCE IS LOW. WITH
LIGHT WINDS TONIGHT...MAY ALSO SEE AREAS OF MVFR FOG DEVELOP ACROSS
PORTIONS OF THE REGION.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
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
556 PM CST SAT FEB 4 2012
.SHORT TERM...TONIGHT THROUGH TUESDAY
341 PM CST SAT FEB 4 2012
AT 3 PM...A 1034 MB HIGH WAS CENTERED OVER THE CENTRAL DAKOTAS.
THIS HIGH HAS CREATED A RATHER STRONG SUBSIDENCE INVERSION BELOW
950 MB AND THIS HAS TRAPPED IN THE LOW CLOUDS AND FOG ACROSS WEST
CENTRAL AND NORTHWEST MINNESOTA...SOUTH CENTRAL MINNESOTA...AND
MUCH OF THE DAKOTA. THE SUNSHINE THIS AFTERNOON HAS HAS CAUSE SOME
DISSIPATION OF THE FOG AND LOW CLOUDS ACROSS THE CITIES AND IN
DODGE COUNTY. MEANWHILE...A LONG DEFORMATION ZONE EXTENDED FROM
THE UPPER LEVEL LOW LOCATED OVER CENTRAL NEBRASKA AND CENTRAL
KANSAS...EAST ACROSS CENTRAL IOWA...AND THEN SOUTH TO SURFACE LOW
LOCATED OVER WESTERN KENTUCKY. CLOSER TO HOME...MOSTLY SUNNY SKIES
HAVE PERSISTED ACROSS OUR FORECAST AREA. WITH ABUNDANT
SUNSHINE...TEMPERATURES HAVE CLIMBED INTO THE 35 TO 45 DEGREE
RANGE. THE WARMEST TEMPERATURES HAVE BEEN FOUND IN THE CONIFER AREAS
OF CENTRAL AND NORTH CENTRAL WISCONSIN. THIS IS FAIRLY TYPICAL DURING
FEBRUARY AND MARCH. THIS IS SIMPLY A RESULT OF THE TREES HAVING A
MUCH LOWER ALBEDO THAN THE AREAS WHICH STILL HAVE SOME SNOW
COVER...AND A SLIGHTLY HIGHER SUN ANGLE.
WITH THE HIGH PRESSURE AREA SLOWLY SLIDING SOUTH ACROSS THE
CENTRAL PLAINS TONIGHT...THERE WILL BE LITTLE CHANGE IN THE
STRENGTH OF THE SUBSIDENCE INVERSION TONIGHT. BOTH THE HRRR AND
RUC INDICATE THAT THE 975 MB MOISTURE /ASSOCIATED WITH THE LOW
CLOUDS AND FOG TO OUR WEST AND NORTHWEST/ WILL MOVE SOUTHEAST INTO
THE FORECAST AREA TONIGHT. HOWEVER DUE TO THE WIND SPEEDS IN THE 5
TO 10 KNOT RANGE...THINKING THAT A MAJORITY OF THIS MOISTURE WILL
REMAIN AS CLOUDS...SO HIT THE CLOUD COVER HARDER THAN THE FOG.
LIKE THIS MORNING...THERE MAY BE SOME PATCHY AREAS OF DENSE FOG.
HOWEVER IF THE WINDS ALOFT ARE LIGHTER THAN
ANTICIPATED...WIDESPREAD DENSE FOG COULD BE A POSSIBILITY.
ON SUNDAY MORNING...THERE SHOULD BE NO CLOUDS ABOVE THE LOW LAYER
CLOUDS AND FOG. THEREFORE...THE SUN SHOULD HAVE BETTER SUCCESS
THAN EARLIER THIS WEEK AT ERODING THE CLOUD DECK DURING THE LATE
MORNING AND EARLY AFTERNOON. THIS SHOULD ALLOW ENOUGH HOURS OF SUNSHINE
FOR OUR TEMPERATURES TO ONCE AGAIN CLIMB TO NEAR 40 DURING THE MID
TO LATE AFTERNOON.
UNDER MAINLY CLEAR SKIES ON SUNDAY NIGHT...THE TEMPERATURES SHOULD
FALL THROUGH EVENING AND EARLY OVERNIGHT...AND THEN AS WARM AIR
ADVECTION DEVELOPS ACROSS THE AREA IN ADVANCE OF A LONG WAVE
TROUGH TEMPERATURES WILL EITHER BECOME STEADY OR SLOWLY RISE. DUE
TO THIS...WENT WITH A NON DIURNAL TEMPERATURE CURVE FOR SUNDAY
NIGHT AND MONDAY MORNING.
ON MONDAY...IT CONTINUES TO LOOK LIKE THERE WILL BE PLENTY
SUNSHINE ACROSS THE REGION. IN ADDITION...THERE WILL BE 4 TO 6C
925 MB TEMPERATURES TO MIX DOWN TO THE SURFACE THROUGH DIURNAL
MIXING. THIS IN COMBINATION WITH A DWINDLING SNOW PACK WILL RESULT
IN TEMPERATURES CLIMBING INTO THE MID TO UPPER 40S.
FROM LATE MONDAY NIGHT INTO TUESDAY...A CANADIAN COLD FRONT WILL
PUSH SOUTH THROUGH THE REGION. THIS IS 12 TO 18 HOURS SLOW THAN
YESTERDAY. THIS WILL MARK A RETURN OF NORMAL TEMPERATURES TO THE
FORECAST AREA. THE NAM/WRF HAS A DEEPER LAYER OF LOW LEVEL
MOISTURE...SO IT GENERATES SOME LIGHT SNOW OR FLURRIES ALONG AND
IN THE WAKE OF THIS FRONT. MEANWHILE THE GEM...GFS...AND ECMWF
HAVE A VERY SHALLOW LAYER OF MOISTURE...SO NONE OF THEM GENERATE
ANY PRECIPITATION. SINCE THE LATTER MODELS HAVE BEEN MORE
CONSISTENT...THE DRY FORECAST WAS MAINTAINED. HOWEVER THE
PRECIPITATION CHANCES WERE RAISED A BIT TO TAKE IN ACCOUNT THIS
VERY SMALL POSSIBILITY FOR SOME VERY LIGHT SNOW.
.LONG TERM...TUESDAY NIGHT THROUGH SATURDAY
341 PM CST SAT FEB 4 2012
THERE CONTINUES TO BE MUCH UNCERTAINTY WITH THE WESTERN EXTENT OF
THE LONG WAVE TROUGH ACROSS EASTERN NORTH NORTH AMERICA. HOWEVER
THE 04.12Z ECMWF HAS COME MORE IN AGREEMENT WITH THE OPERATIONAL
GFS AND ITS FAMILY MEMBERS. IT NOW SHOWS THAT THE COLDEST AIR WILL
REMAIN OFF TO OUR NORTHEAST..AND THE ARCTIC AIR WILL BE GLANCING
THE AREA BEFORE A QUICK RETURN TO ABOVE-NORMAL TEMPERATURES. HIGH
TEMPERATURES FOR FRIDAY AND SATURDAY WILL LIKELY RANGE FROM THE
TEENS TO MID 20S WHICH IS AROUND 5 TO 10 DEGREES BELOW NORMAL FOR
THIS TIME OF YEAR. THIS GLANCING BRUSH OF ARCTIC TEMPERATURES HAS
BEEN WELL INDICATED BY THE CFS VERSION 2 FOR NEARLY TWO WEEKS.
THIS UPPER AIR PATTERN ALSO FITS IN WELL WITH THE ANOMALOUS
CONVECTION OVER THE CENTRAL AND WESTERN PACIFIC RETROGRADING
WESTWARD TOWARD INDONESIA.
WITH THE GEM...GFS...AND ECMWF CONTINUING TO SHOW THAT THIS TIME
PERIOD WOULD REMAIN MAINLY DRY...KEPT THE DRY FORECAST INTACT.
&&
.AVIATION...TONIGHT AND SUNDAY
556 PM CST SAT FEB 4 2012
BIGGEST CHALLENGE THIS PERIOD IS THE MOVEMENT / EXPANSION OF THE
STRATUS CURRENTLY ACROSS SOUTHERN MINNESOTA AND EASTERN PARTS OF
THE DAKOTAS. NEAR-TERM GUIDANCE / HRRR AND RUC / SUGGESTS STRATUS
WILL EXPAND AND SLOWLY MOVE SOUTHEAST...BRINGING IFR / LIFR
CEILINGS AT 01Z TO KRST...AND IFR CEILINGS TO KLSE AT 04Z.
STRATUS DECK WILL REMAIN IN PLACE THROUGH SUNDAY MORNING. THERE IS
POTENTIAL FOR FOG DEVELOPMENT AT KRST FOR A BRIEF PERIOD EARLY
SUNDAY MORNING PER NAM / GFS FORECAST SOUNDINGS AND GUIDANCE. THE MAIN
TIMING WOULD BE CENTERED BETWEEN 12Z AND 14Z. RIGHT NOW...CONFIDENCE
IS LOW ON THIS SCENARIO AS EXPECTING SURFACE WINDS BETWEEN 6 TO 10
KTS TO PROMOTE ENOUGH MIXING TO PREVENT FOG.
STRATUS WILL BE SLOW TO ERODE DURING THE MORNING HOURS SUNDAY.
CURRENT THINKING IS THAT AROUND 18Z AT BOTH TAF SITES SUNSHINE /
DAYTIME MIXING WILL WIN OUT AND CONDITIONS WILL IMPROVE TO VFR
FOR THE REMAINDER OF THE TAF PERIOD.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
245 PM CST SAT FEB 4 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...TAYLOR
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
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 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 MIAMI FL
1239 AM EST SUN FEB 5 2012
.AVIATION...THRU 06Z MON.
PLENTY OF CLOUD COVERAGE WITH ISOLATED TO SCATTERED SHOWERS
DEVELOPING AND SPREADING NORTHWEST OVER SOUTH FLORIDA CONTINUES
TO BE SUPPORTED IN THE LATEST MODEL GUIDANCE THROUGH THE EXTENT OF
THIS FORECAST CYCLE. SUB VFR CONDITIONS FOR BRIEF PERIODS WILL
CERTAINLY REMAIN A POSSIBILITY DUE TO REDUCED CIGS/VSBYS IN AND
AROUND THESE DEVELOPING SHOWERS. THE LOW-LEVEL FLOW WILL REMAIN
OUT OF THE SOUTHEAST AS A WEAK AREA OF LOW PRESSURE EVOLVES
ACROSS THE SOUTH- CENTRAL GULF OF MEXICO TODAY. 85/AG
&&
.PREV DISCUSSION... /ISSUED 836 PM EST SAT FEB 4 2012/
UPDATE...
NO CHANGES TO THE EXISTING FORECAST AT THIS TIME ...
SHOWERS CONTINUE TO AFFECT THE COASTAL WATERS OF THE EAST COAST, MAINLY
SECTIONS OF BROWARD AND PALM BEACH COUNTIES THIS EVENING. ISOLATED
TO SCATTERED SHOWERS WILL CONTINUE TONIGHT DUE TO THE MODERATE
EASTERLY FLOW AND SUFFICIENT MOISTURE DEPTH. WARM TEMPERATURES CAN
BE EXPECTED AGAIN TONIGHT WITH LOWS IN THE 60S TO AROUND 70.
THE RUC RAPID REFRESH MODEL FOR TONIGHT GENERATES CONVECTIVE
ACTIVITY OVER THE GULF OF MEXICO OUTSIDE OF THE GULF COASTAL
WATERS. HOWEVER, IT HINTS AT INCREASED SHOWER ACTIVITY TOWARD THE
EARLY MORNING HOURS OVER MIAMI-DADE AND BROWARD. THE SPC MESOSCALE
ANALYSIS SHOWS MOISTURE CONVERGENCE AND AN INCREASE IN THETA AND
MIXING RATION BETWEEN BROWARD AND PALM BEACH COUNTIES FOR THE PAST HOUR,
WHICH COINCIDES WITH THE AREA OF SHOWER ACTIVITY OBSERVED AT THE
PRESENT TIME.
THE FORECAST REASONING REMAINS UNCHANGED. AN UPPER LEVEL
TROUGH THAT EXTENDS FROM THE YUCATAN INTO THE CENTRAL/EASTERN
GULF WILL MOVE TOWARDS SOUTH FLORIDA/FLORIDA STRAITS ON SUNDAY
INTO MONDAY...WITH PWATS SLOWLY INCREASING THROUGH THIS TIME. THE
PRECIP AMOUNTS ARE STILL EXPECTED TO BE ON THE LIGHT TO MODERATE
SIDE...WITH RAINFALL TOTALS OF 1/4 TO 1/2 AN INCH FOR THE NAPLES
AND WEST OF LAKE OKEECHOBEE...AND 1/2 TO 1.5 INCHES FOR THE EAST
COAST METRO REGIONS.
PREV DISCUSSION... /ISSUED 704 PM EST SAT FEB 4 2012/
AVIATION...LITTLE CHANGE IN THE EXPECTED CONDITIONS OVER THE NEXT
12 HOURS WITH CONTINUED EASTERLY FLOW AND ISOLATED TO SCATTERED
SHOWER ACTIVITY. CEILINGS WILL BECOME A BIT LOWER OVERNIGHT WITH
BRIEF MVFR CONDITIONS POSSIBLE, EXCEPT AT KPBI, WHERE THEY WILL
BE MORE PREVALENT. WINDS WILL BECOME SOUTHEAST AT 10-13 KNOTS BY
SUNDAY MORNING WITH SHOWER ACTIVITY SLOWLY BECOMING MORE NUMEROUS
THROUGHOUT THE DAY. A FEW TSRA COULD FORM BY SUNDAY AFTERNOON,
BUT WILL ONLY MENTION VCSH AT THIS TIME.
PREV DISCUSSION... /ISSUED 303 PM EST SAT FEB 4 2012/
DISCUSSION...
SURFACE HIGH PRESSURE IS MOVING EAST INTO THE ATLANTIC AS LOW
PRESSURE MOVES INTO THE TENNESSEE VALLEY. THIS WILL ALLOW THE
PRESSURE GRADIENT TO SLOWLY RELAX TONIGHT AND SUNDAY...WITH WINDS
VEERING TO THE SOUTHEAST. ISOLATED TO SCATTERED SHOWERS WILL
CONTINUE TONIGHT DUE TO THE MODERATE EASTERLY FLOW AND SUFFICIENT
MOISTURE DEPTH. WARM TEMPERATURES CAN BE EXPECTED AGAIN TONIGHT
WITH LOWS IN THE 60S TO AROUND 70. MOSTLY CLOUDY SKIES CAN BE
EXPECTED TONIGHT THROUGH THE BEGINNING OF NEXT WEEK DUE TO UPPER
LEVEL CLOUDINESS FROM A LOW LEVEL TROUGH THAT EXTENDS FROM THE
YUCATAN INTO THE CENTRAL/EASTERN GULF. THIS FEATURE WILL MOVE
TOWARDS SOUTH FLORIDA/FLORIDA STRAITS ON SUNDAY INTO MONDAY...WITH
PWATS SLOWLY INCREASING THROUGH THIS TIME. MODEL SOLUTIONS DIFFER
ON HOW FAST AND HOW FAR NORTH THE LOW/MID LEVEL MOISTURE WILL MOVE
INTO THE REGION. THE GFS HAS THE MOISTURE FURTHER NORTH THAN THE
ECMWF ON THE 12Z RUNS...BRINGING THE MOISTURE IN MOST OF THE
REGION LATE SUNDAY AFTERNOON THROUGH MONDAY MORNING. THE ECMWF
ONLY BRINGS IN THE DEEPEST MOISTURE TO THE SOUTHERN PORTION OF THE
REGION. THIS DIFFERS FROM THE 00Z RUN...AND THE 00Z SOLUTION WAS
MORE SIMILAR TO THE GFS. HOWEVER...IT APPEARS THAT MUCH NEEDED
RAINFALL WILL BE MOVING INTO THE REGION LATE SUNDAY THROUGH
MONDAY.
THE RIGHT ENTRANCE REGION OF A WEAK UPPER JET WILL BE OVER THE
REGION SUNDAY AFTERNOON INTO THE SUNDAY EVENING AND THIS WILL
ENHANCE LIFT AT THE SAME TIME MOISTURE IS INCREASING OVER THE
REGION. SO KEPT CHANCE POPS SUNDAY FOR MOST OF SOUTH FLORIDA.
BUMPED UP POPS TO HIGH END CHANCE TO LIKELY FOR THE SOUTHERN AND
SOUTHEAST PORTIONS OF THE CWA FOR SUNDAY NIGHT. ALSO KEPT MENTION
OF THUNDER FOR THE SOUTHERN HALF OF THE REGION FOR SUNDAY
AFTERNOON AND SUNDAY NIGHT. THE DEEPER MOISTURE MAY BE MOVING OUT
OF THE REGION MONDAY MORNING...BUT A WEAK FRONTAL BOUNDARY IS
EXPECTED TO MOVE TOWARDS SOUTH FLORIDA. THE LOW LEVEL TROUGH MAY
ALSO STAY OVER THE REGION THROUGH MONDAY AFTERNOON. SO BUMPED UP
POPS TO CHANCE TO LIKELY ACROSS THE REGION ON MONDAY. ATTM...IT
APPEARS THE PRECIP AMOUNTS MAY BE ON THE LIGHT TO MODERATE
SIDE...WITH RAINFALL TOTALS OF 1/4 TO 1/2 AN INCH FOR THE NAPLES
AND WEST OF LAKE OKEECHOBEE...AND 1/2 TO 1.5 INCHES FOR THE EAST
COAST METRO REGIONS. WENT BELOW GUIDANCE FOR HIGH TEMPERATURES ON
MONDAY BY A COUPLE DEGREES DUE TO EXPECTED CLOUD COVER AND
RAINFALL.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 79 67 77 67 / 30 50 50 20
FORT LAUDERDALE 79 67 79 69 / 40 60 60 20
MIAMI 80 67 79 69 / 40 60 60 20
NAPLES 80 65 79 64 / 30 30 30 20
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
DISCUSSION/MARINE/FIRE...60/BD
AVIATION/RADAR...85/AG
AREA FORECAST DISCUSSION
NWS LINCOLN IL
244 AM CST SUN FEB 5 2012
.DISCUSSION...
ISSUED 240 AM CST SUN FEB 5 2012
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL U.S. EARLY THIS
MORNING...WITH WATER VAPOR IMAGERY SHOWING IT CENTERED NEAR KANSAS
CITY...WITH A SECOND LOW FURTHER WEST ACROSS UTAH. CLEARING LINE
HAS BEEN QUICKLY MOVING SOUTH ACROSS THE NORTHERN CWA THE LAST FEW
HOURS...AND WAS JUST SOUTH OF THE I-74 CORRIDOR AT 2 AM. INITIAL
FORECAST CHALLENGE WILL BE WITH CLEARING TREND AND FOG POTENTIAL
EARLY ON...AS CLOUDS BREAK IN AREAS THAT HAD DECENT RAINFALL THE
LAST 24-36 HOURS. HOWEVER...THE PRIMARY FORECAST ISSUE WILL BE
WITH TREND FOR COLD WEATHER TOWARD THE END OF THE WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
LATEST HRRR NOT TOO FAR OFF WITH CURRENT POSITIONING OF THE
STRATUS...AND SHOWS MUCH OF THE CWA SHOULD BE STRATUS-FREE BY LATE
MORNING. NORTHERN CWA IS MOST VULNERABLE FOR SOME FOG EARLY...WITH
LACON CURRENTLY REPORTING 3/4 MILE AND BLOOMINGTON 1-3/4 MILE AS
THE CLOUDS HAVE BROKEN. SO FAR NOTHING NORTH OF THERE IS GETTING
OUT OF HAND YET DESPITE A LONGER CLEAR PERIOD...SO WILL MAKE A
LAST MINUTE DECISION ON WHETHER TO CONTINUE FOG POTENTIAL BEYOND
SUNRISE.
MISSOURI UPPER LOW PROGGED TO DRIFT SOUTHEAST TO THE LOWER OHIO
VALLEY BY TONIGHT. ANY RESIDUAL LIGHT RAIN/DRIZZLE WILL CONTINUE
TO SHRINK WITH THIS LOW...AND WILL LIKELY ONLY MENTION IT IN THE
FAR SOUTHEAST FOR EARLY TODAY. SURFACE HIGH PRESSURE RIDGING
EASTWARD POSES ANOTHER CONCERN FOR LOW CLOUDS/FOG TONIGHT. LATEST
SREF GRAPHICS SHOWING THE NORTHWEST CWA BEING OVERSPREAD BY LOWER
STRATOCUMULUS AFTER MIDNIGHT...LASTING UNTIL ABOUT MID-MORNING
MONDAY. GIVEN THAT THIS AREA SHOULD SEE DECENT SUNSHINE MUCH OF
TODAY TO HELP DRY THINGS OUT...AM NOT OVERLY CONFIDENT IN THIS
CLOUD SCENARIO AT THE MOMENT. FOR NOW...WILL GO WITH PARTLY CLOUDY
CONDITIONS ACROSS THE NORTHWEST TONIGHT AND MAINLY CLEAR
ELSEWHERE...WITH THE DAY SHIFT MAKING ANY FURTHER ADJUSTMENTS AS
THE DAYTIME TRENDS PLAY OUT.
LEFTOVER CUTOFF ENERGY OVER THE CENTRAL ROCKIES SHOULD WEAKEN AND
GET PICKED UP BY A TROUGH MOVING ALONG THE CANADIAN BORDER MONDAY
NIGHT AND TUESDAY. NOT A LOT OF MOISTURE AVAILABLE OVERHEAD WHEN
IT ARRIVES...BUT SOME RESIDUAL MOISTURE ACCOMPANYING THE LEFTOVER
ENERGY IS ENOUGH TO WARRANT SLIGHT CHANCE POPS FOR TUESDAY AND
TUESDAY NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY...
QUIET WEATHER EXPECTED MIDWEEK AS HIGH PRESSURE DRIFTS ACROSS THE
MIDWEST. MAIN CONCERN REMAINS WITH THE AMOUNT OF ARCTIC AIR THAT
WILL BE DROPPING SOUTHEASTWARD LATE IN THE WEEK. GFS BRINGS 850 MB
TEMPERATURES OF -16C ACROSS MOST OF THE CWA BY FRIDAY EVENING...
WHILE ECMWF GIVES US MORE OF A GLANCING BLOW WITH THE CORE OF THE
COLDER AIR CLOSER TO THE GREAT LAKES. HAVE BEGUN TO TREND DOWNWARD
WITH THE TEMPERATURE FORECASTS AS THE MAIN IDEA HAS BEEN
PERSISTENT FOR A COUPLE DAYS NOW...BUT NOT AS AGGRESSIVELY AS THE
GFS WOULD INDICATE...WHICH GIVES THE NORTHERN CWA A STRUGGLE TO
REACH 20 DEGREES ON FRIDAY. THAT MAY BE TOUGH WITHOUT ANY SNOW ON
THE GROUND...BUT WE SHOULD STILL SEE SOMEWHAT OF A COLD SNAP IN
AN OTHERWISE MILD WINTER.
GEELHART
&&
.AVIATION...
ISSUED 1125 PM CST SAT FEB 4 2012
IFR CONDITIONS WILL CONTINUE AT SPI/DEC/CMI FOR A 2-3 MORE HOURS
AS THE LOWER CLOUDS WILL CONTINUE TO BE PUSHED SOUTH OVERNIGHT.
CMI SHOULD GO FIRST AROUND 08Z WITH SPI & DEC AT 09Z. THEN AC
CLOUDS AROUND 8KFT WILL DOMINATE THE AREA UNTIL THE MORNING HOURS.
PIA IS ALREADY THERE WITH VFR CONDITIONS WHILE BMI SHOULD BE
THERE AT TAF ISSUANCE TIME...THOUGH WITH SOME LIGHT FOG. WITH PIA
AND BMI CLEARING OUT FIRST IN THE EARLY MORNING HOURS...BELIEVE
SOME LIGHT FOG IS POSSIBLE. SO HAVE A THIS IN THE TAFS WITH A 3HR
TEMPO GROUP FOR LOWER VIS. COULD BE SOME LIGHT FOR AT SPI/DEC/CMI
BUT ONLY TEMPO SINCE THEY WILL NOT CLEAR OUT UNTIL AFTER SUNRISE.
WITH LOTS OF LOW LEVEL MOISTURE AROUND FROM THE RAIN LAT NIGHT AND
TODAY...BELIEVE ONCE THE SUN HITS IT...CU WILL DEVELOP FOR THE
LATE MORNING AND INTO THE AFTERNOON. WITH RIDGING AND ANTICYCLONIC
FLOW MOVING IN WILL GO WITH ONLY SCATTERED CU AND NO BROKEN CIGS.
HEIGHT OF CU SHOULD BE AROUND 3KFT. CU WILL DISSIPATE DURING THE
EVENING LEAVING CLEAR SKIES FOR THE EVENING HOURS. NORTH-NORTHEAST
WINDS WILL BECOME NORTHERLY DURING THE MORNING HOURS AND DECREASE
IN SPEED AS SURFACE RIDGING BUILDS IN FROM THE WEST. THEN EXPECT
NORTHWEST WINDS TOMORROW EVENING.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
354 AM EST SUN FEB 5 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.
&&
.NEAR TERM /TODAY/...
LIGHT PRECIP AND DRIZZLE RAPIDLY DECREASING IN COVERAGE TO THE
SOUTHEAST OF THE INDY METRO EARLY THIS MORNING...AND EXPECT IT TO BE
CLEAR OF THE FORECAST AREA BY 09-10Z. BACK EDGE OF LOWER CLOUDS ALSO
RAPIDLY DROPPING SOUTH AS DRIER AIR SPREADS INTO THE LOWER GREAT
LAKES. TEMPS WERE HOVERING NEAR FREEZING ACROSS FAR NORTHERN
SECTIONS OF THE FORECAST AREA WHERE SKIES HAD ALREADY CLEARED...WITH
MID AND UPPER 30S ELSEWHERE AT 08Z.
PRIMARY CHALLENGES FOR TODAY FOCUS OVER THE NEXT SIX HOURS THROUGH
MID MORNING WITH RESPECT TO LOW CLOUD COVERAGE AND THE POSSIBILITY
OF FOG DEVELOPMENT AS SKIES CLEAR. MOS AND LAMP GUIDANCE NOT
CAPTURING THE RAPIDITY OF THE CLEARING VERY WELL AND EVEN THE MOST
RECENT RUC DATA SEEMS TO BE FALLING BEHIND A BIT WITH RESPECT TO THE
SOUTHWARD SURGE IN CLEARING SINCE MIDNIGHT. ALREADY AT 08Z CLEARING
LINE IS APPROACHING THE NORTHERN INDY SUBURBS. HOWEVER...BACK EDGE
OF THE STRATOCU NOT PROGRESSING SOUTH AS QUICKLY OVER FAR EASTERN
INDIANA AND WESTERN OHIO. WITH LIGHT NORTHEAST FLOW THROUGH THE
LOWER LEVELS...QUITE PLAUSIBLE THAT THIS MAY SLOW THE DEPARTURE OF
THE STRATOCU ALONG THE I-70 CORRIDOR UNTIL CLOSER TO DAYBREAK. FOR
NOW...WILL MAINTAIN CLOUDS SOUTH OF I-70 THROUGH DAYBREAK WITH CLEAR
SKIES TO THE NORTH. POTENTIAL FOR FOG DEVELOPMENT IS GREATER OVER
NORTHERN COUNTIES WITH THE CLEARING. POSSIBILITY DOES EXIST FOR
THICKER FOG TO IMPACT A FEW LOCATIONS OVER FAR NORTHERN COUNTIES BUT
OVERALL LIGHT NORTHERLY FLOW AND CONTINUED EXPANSION OF DRIER
AIRMASS FROM THE NORTH SHOULD KEEP THICKER FOG CONFINED TO LOCALIZED
AREAS. WILL CARRY PATCHY FOG NORTH OF I-70 INTO MID MORNING AND
ADJUST ACCORDINGLY AS NEEDED. CONTINUING A MENTION OF PATCHY
FREEZING FOG OVER FAR NORTHERN COUNTIES WHERE SURFACE TEMPS LIKELY
TO BOTTOM OUT AT 28-30 DEGREES.
REMAINDER OF THE DAY WILL BE QUIET AS SKIES BECOME SUNNY UNDER
STRONG HIGH PRESSURE RIDGE. MODEL SOUNDINGS SHOW DEEP SUBSIDENCE
TAKING HOLD WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW EXPECTED FOR
THE REST OF THE DAY.
TEMPS...MOS GUIDANCE SUPPORTED BY LOW LEVEL THERMALS AS TEMPS SHOULD
WARM INTO THE MID AND UPPER 40S THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.
MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.
MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.
TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.
THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.
&&
.AVIATION /DISCUSSION FOR THE 05/09Z TAF UPDATE/...
UPDATE...
THE NEXT FEW HOURS CONTINUE TO BE THE CRITICAL TIME FRAME FOR FOG
DEVELOPMENT AT KIND. CLEARING HAS ALREADY TAKEN PLACE AT
KLAF...AND THE LINE IS CURRENTLY JUST TO THE NORTH OF KIND.
HOWEVER...VISIBILITIES HAVE NOT DROPPED DRASTICALLY AT KLAF OVER
THE LAST FEW HOURS WITH CLEAR SKIES...SO WILL BASE KIND ON THAT
TREND FOR NOW. SO...ALL INDICATIONS AT THIS TIME ARE LEADING TO
MVFR CONDITIONS THROUGH DAYBREAK...AND CONTINUED IMPROVEMENT
AFTER THAT.
PREVIOUS DISCUSSION...
RESTRICTIONS LIKELY IN SOME FORM THROUGH THE MORNING
HOURS...IMPROVING TO VFR THEREAFTER.
QUESTION IS WHERE CLEARING WILL OCCUR AND FOG WILL DEVELOP. LAF MOST
LIKELY TO SEE CLEARING...BUT IND CANNOT BE RULED OUT. 10-12Z WILL BE
THE MOST CRITICAL TIME FRAME AT IND. IF MOISTURE SCOURS OUT ENOUGH
TO CLEAR...DENSE FOG COULD BE POSSIBLE. AS IT LOOKS NOW...EXPECTING
IFR LOW CLOUD TO CONTINUE THROUGH THE MORNING WITH MAINLY MVFR
VISIBILITIES.
WINDS WILL GO FROM EAST/NORTHEASTERLY TO MORE NORTHERLY
OVERNIGHT...BUT SPEEDS SHOULD GENERALLY REMAIN LESS THAN 10KT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...NIELD/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
334 AM EST SUN FEB 5 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.
&&
.NEAR TERM /TODAY/...
LIGHT PRECIP AND DRIZZLE RAPIDLY DECREASING IN COVERAGE TO THE
SOUTHEAST OF THE INDY METRO EARLY THIS MORNING...AND EXPECT IT TO BE
CLEAR OF THE FORECAST AREA BY 09-10Z. BACK EDGE OF LOWER CLOUDS ALSO
RAPIDLY DROPPING SOUTH AS DRIER AIR SPREADS INTO THE LOWER GREAT
LAKES. TEMPS WERE HOVERING NEAR FREEZING ACROSS FAR NORTHERN
SECTIONS OF THE FORECAST AREA WHERE SKIES HAD ALREADY CLEARED...WITH
MID AND UPPER 30S ELSEWHERE AT 08Z.
PRIMARY CHALLENGES FOR TODAY FOCUS OVER THE NEXT SIX HOURS THROUGH
MID MORNING WITH RESPECT TO LOW CLOUD COVERAGE AND THE POSSIBILITY
OF FOG DEVELOPMENT AS SKIES CLEAR. MOS AND LAMP GUIDANCE NOT
CAPTURING THE RAPIDITY OF THE CLEARING VERY WELL AND EVEN THE MOST
RECENT RUC DATA SEEMS TO BE FALLING BEHIND A BIT WITH RESPECT TO THE
SOUTHWARD SURGE IN CLEARING SINCE MIDNIGHT. ALREADY AT 08Z CLEARING
LINE IS APPROACHING THE NORTHERN INDY SUBURBS. HOWEVER...BACK EDGE
OF THE STRATOCU NOT PROGRESSING SOUTH AS QUICKLY OVER FAR EASTERN
INDIANA AND WESTERN OHIO. WITH LIGHT NORTHEAST FLOW THROUGH THE
LOWER LEVELS...QUITE PLAUSIBLE THAT THIS MAY SLOW THE DEPARTURE OF
THE STRATOCU ALONG THE I-70 CORRIDOR UNTIL CLOSER TO DAYBREAK. FOR
NOW...WILL MAINTAIN CLOUDS SOUTH OF I-70 THROUGH DAYBREAK WITH CLEAR
SKIES TO THE NORTH. POTENTIAL FOR FOG DEVELOPMENT IS GREATER OVER
NORTHERN COUNTIES WITH THE CLEARING. POSSIBILITY DOES EXIST FOR
THICKER FOG TO IMPACT A FEW LOCATIONS OVER FAR NORTHERN COUNTIES BUT
OVERALL LIGHT NORTHERLY FLOW AND CONTINUED EXPANSION OF DRIER
AIRMASS FROM THE NORTH SHOULD KEEP THICKER FOG CONFINED TO LOCALIZED
AREAS. WILL CARRY PATCHY FOG NORTH OF I-70 INTO MID MORNING AND
ADJUST ACCORDINGLY AS NEEDED. CONTINUING A MENTION OF PATCHY
FREEZING FOG OVER FAR NORTHERN COUNTIES WHERE SURFACE TEMPS LIKELY
TO BOTTOM OUT AT 28-30 DEGREES.
REMAINDER OF THE DAY WILL BE QUIET AS SKIES BECOME SUNNY UNDER
STRONG HIGH PRESSURE RIDGE. MODEL SOUNDINGS SHOW DEEP SUBSIDENCE
TAKING HOLD WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW EXPECTED FOR
THE REST OF THE DAY.
TEMPS...MOS GUIDANCE SUPPORTED BY LOW LEVEL THERMALS AS TEMPS SHOULD
WARM INTO THE MID AND UPPER 40S THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.
MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.
MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.
TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.
THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.
&&
.AVIATION /DISCUSSION FOR THE 05/06Z TAFS/...
RESTRICTIONS LIKELY IN SOME FORM THROUGH THE MORNING
HOURS...IMPROVING TO VFR THEREAFTER.
QUESTION IS WHERE CLEARING WILL OCCUR AND FOG WILL DEVELOP. LAF MOST
LIKELY TO SEE CLEARING...BUT IND CANNOT BE RULED OUT. 10-12Z WILL BE
THE MOST CRITICAL TIME FRAME AT IND. IF MOISTURE SCOURS OUT ENOUGH
TO CLEAR...DENSE FOG COULD BE POSSIBLE. AS IT LOOKS NOW...EXPECTING
IFR LOW CLOUD TO CONTINUE THROUGH THE MORNING WITH MAINLY MVFR
VISIBILITIES.
WINDS WILL GO FROM EAST/NORTHEASTERLY TO MORE NORTHERLY
OVERNIGHT...BUT SPEEDS SHOULD GENERALLY REMAIN LESS THAN 10KT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS DES MOINES IA
310 PM CST SUN FEB 5 2012
.SHORT TERM /TODAY/...
WIDESPREAD STRATUS FIELD CURRENTLY PUSHING SOUTH THOUGH NORTHERN IA
EARLY THIS MORNING AND REPRESENTS THE FORECAST CHALLENGE OF THE DAY.
THE STRATUS HAS BE SHIFTING SOUTH AT 16 KTS THE PAST FEW HOURS. THIS
WOULD BRING IT TO THE MISSOURI BORDER AROUND 16Z. THE HRRR HAS
INITIALIZED THE CLOUD PROGRESSION WELL AND SUGGESTS THEY WILL STICK
AROUND MOST OF THE DAY. IF ANY EROSION DOES OCCUR...IT WILL BE ON
THE OUTSIDE EDGES AND THIS WOULD LEAVE CENTRAL IA THE LAST TO
DISSIPATE. WITH NEW SNOW PACK OVER THE SOUTH...LIGHT WINDS AND LACK
OF STRONG SUBSIDENCE...FAVOR THE CLOUDY SOLUTION. THE LACK OF SUN
WILL RESULT IN BELOW GUIDANCE HIGHS TODAY. EXPECT SOME FOG EARLY IN
THE PERIOD AND THE POSSIBILITY REMAINS OF LOCALLY DENSE FOG. BEST
POTENTIAL WILL BE SOUTH OF HIGHWAY 30 AS THE HIGHER DEWPOINTS
ASSOCIATED WITH THE STRATUS SETTLES OVER THE NEW SNOW PACK WHERE
CONDITIONS HAVE ALREADY RADIATED.
.LONG TERM /TONIGHT THROUGH SATURDAY/...
OVERALL MID/LONG RANGE REMAINS RELATIVELY QUIET THROUGH THE
PERIOD...WITH MAINLY DRY CONDITIONS. ISSUE TONIGHT INTO
MONDAY...WILL BE IF STRATUS MOVING INTO THE CWA...WILL LINGER INTO
TONIGHT ACROSS THE AREA/BREAKUP/OR POSSIBLY EVEN REDEVELOP.
STRATUS/FOG HAS BEEN QUITE PERSISTENT ACROSS THE AREAS EAST OF THE
SFC HIGH PRES RIDGE SITUATED ACROSS THE CENTRAL DAKOTAS INTO NE/KS
THE PAST FEW DAYS...THEREFORE EXPECT THIS TREND TO CONTINUE TONIGHT.
THEREFORE HAVE INCREASED CLOUD COVER ACROSS THE SOUTHERN CWA
TONIGHT...AND ADDED IN A MENTION OF FOG AS HIGHER MOISTURE AIR
REMAINS IN PLACE OVER NEW SNOWPACK. OTHERWISE AS WINDS BECOME MORE
WESTERLY TO SOUTHWESTERLY AHEAD OF THE NEXT SYSTEM...EXPECT
CLOUDS/FOG TO ERODE ACROSS THE AREA MONDAY. TWO SYSTEMS OF NOTE
MONDAY INTO MONDAY NIGHT...WITH UPPER LEVEL SPLIT FLOW REGIME IN
PLACE. ONE STRENGTHENING UPPER LOW SITUATED ALONG THE FRONT RANGE OF
THE ROCKIES TUESDAY...EXPECTED TO SLIDE EAST INTO TUESDAY. ANOTHER
UPPER LEVEL SHORTWAVE DROPPING SOUTHEASTWARD FROM SASK/ALBERTA
THROUGH THE DAKOTAS/MN. THESE SYSTEMS TO MERGE OVER THE AREA TUESDAY
INTO TUESDAY NIGHT BRINGING INCREASING CLOUDS...AND POSSIBLY A
CHANCE FOR SOME LIGHT SNOW ACROSS THE SOUTHERN CWA. MAJORITY OF
PRECIPITATION EXPECTED TO FALL SOUTH OF IOWA...BUT SOUNDINGS TRY TO
SATURATE A BIT WITH WEAK LIFT ALONG AND SOUTH OF I-80. THEREFORE DID
EXPAND COVERAGE OF SLIGHT CHANCE POPS TO INCLUDE SOUTHERN HALF OF
CWA FOR TUESDAY...WITH THE SYSTEM QUICKLY SLIDING EAST/SOUTHEASTWARD
TUESDAY NIGHT WITH MAYBE SOME LINGERING SNOW ACROSS THE FAR
SOUTHEAST. OTHERWISE CAA EXPECTED THROUGHOUT THE DAY WITH
CLOUDS...SO EXPECT AN EARLY MAX TEMP WITH STEADY OR FALLING TEMPS
THROUGH THE REMAINDER OF THE DAY. HIGH PRESSURE TO BUILD INTO THE
AREA FOR WEDNESDAY...WITH BROAD UPPER LEVEL TROUGHING STILL EXPECTED
TO DIG SOUTHWARD ACROSS THE CENTRAL/EASTERN US FOR LATE IN THE WEEK.
THIS WILL BRING A COLD FROM SWEEPING THROUGH THE CWA
THURSDAY...SENDING H85 TEMPS INTO THE TEENS BELOW ZERO CELSIUS.
HOWEVER CANADIAN/GFS/PREVIOUS EC MUCH MORE AGGRESSIVE WITH THE SURGE
OF COLD AIR PLUNGING IT MUCH FURTHER SOUTH AND ALLOWING THIS ARCTIC
AIRMASS TO REMAIN IN PLACE ACROSS THE CWA FOR THE WEEKEND. LATEST
00Z EC IS MUCH DIFFERENT...KIND OF BRUSHING THE CWA WITH THE ARCTIC
AIRMASS AND THEN QUICKLY MODERATING THE TEMPS WITH WEAK UPPER
RIDGING INTO THE WEEKEND. THEREFORE SOME UNCERTAINTY WITH TEMPS
TOWARD THE END OF THE PERIOD...SO STUCK NEAR THE CONSALL GUIDANCE
GRIDS...WITH SOME TRENDING TOWARD THE COLDER SOLUTION DUE TO BETTER
CONTINUITY IN THE PAST FEW RUNS.
&&
.AVIATION...05/06Z
LARGE AREA OF STRATUS DROPPING SOUTH FROM MN NOW AND SOLID OVC003
WALL OF CLOUDS HEADING INTO THE AREA. ALREADY NEAR KMCW BY 06Z AND
EXPECTED TO HEAD TOWARD US 20 BY 08-09Z AT KALO AND KFOD. BY 12Z THE
AREA OF LOWER CLOUDS AND VSBY SHOULD BE NEARING KDSM AND THEN
BETWEEN 16-18Z FOR KOTM. WARM AIR ADVECTION ALOFT FROM THE NORTHERN
PLAINS AND SOUTHERN CANADA MAY ACT TO KEEP STRATUS GOING MOST OF THE
DAY ESPECIALLY GIVEN THE COLDER SFC TEMPS ACROSS MOST OF OUR AREA
NOW. WITH NEW SNOW PACK FROM I80 SOUTH TO BORDER...THIS AREA MIGHT
BE SUSCEPTIBLE TO THICK FOG DEVELOPMENT EITHER OVERNIGHT OR ON
SUNDAY AS WELL. NEXT FEW DAYS MAY THE REGION WILL HAVE ADDED
CHALLENGE OF BOUNDARY LAYER MOISTURE AND POSSIBLE ISSUES WITH FOG.
DIFFICULT TO TIME...BUT ONCE IT SETS UP...IT MAY STICK AROUND UNTIL
STRONGER SFC WINDS RETURN MONDAY NIGHT OR TUESDAY. HAVE PASSED
DETAILS ALONG TO NIGHT SHIFT FOR NEXT PACKAGE. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
SHORT TERM...DONAVON
LONG TERM...BEERENDS
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1133 PM CST SAT FEB 4 2012
.UPDATE 05/06Z AVIATION DISCUSSION...
.SHORT TERM /TONIGHT/...
REMAINDER OF WARNINGS/ADVISORIES HAVE BEEN CANCELLED. STORM NOW
SOUTH OF AREA AND CONDITIONS CONTINUE TO IMPROVE.
CONTINUE TO TRIM BACK ADVISORY. EASTERN AREAS OF LIGHT SNOW NEARLY
OVER AND SOUTHWEST CONTINUES LIGHT. WARNING AREA STILL RECEIVING
SOME ADDITIONAL LIGHT SNOW. ALL WILL EXPIRE AT 06Z. NEXT ISSUE IS
FOG AND LOW STRATUS. EXPECTING LOW STRATUS AND FOG TO OVERTAKE
NORTHERN BORDER COUNTIES NEAR MN BORDER BY 06Z AND TRANSLATE SOUTH
TO NEAR DES MOINES BY 12Z. HAVE ADDED AREAS FOG NORTH AND MAINTAIN
PATCHY FOG SOUTH. IF SKIES CLEAR AND FOG GETS A FOOTHOLD...MAY BE
SOME DENSE FOG. DIFFICULT TO DECIDE WHAT AREAS MIGHT BE AT RISK FOR
THAT...GIVEN APPROACHING CLOUDS. UPSTREAM VSBYS LAST NIGHT WERE AT
OR ABOVE 1/2SM SO...MIGHT NOT BE A MAJOR ISSUE WITH THE EXCEPTION OF
FROSTY ROAD SURFACES. WILL NEED TO MONITOR THROUGH THE NIGHT.
HAVE TRIMMED BACK WINTER STORM WARNING WITH THE EXCEPTION OF WHERE
SNOW STILL FALLING IN SW IA. LEAVING ADVISORY AS IS...DUE TO BAND OF
SNOW STILL OCCURRING IN DEF ZONE OVER THE SOUTHEAST. MONITORING AREA
FOR FOG DEVELOPMENT LATE TONIGHT. ADVECTION FOG OVER MN AND
POTENTIAL FOR RADIATION FOG OVER IOWA MAY COMPLICATE TRAVEL
OVERNIGHT AND EARLY SUNDAY MORNING.
.PREVIOUS SHORT TERM /TONIGHT/...
PRIMARY CONCERNS REMAIN SNOW TRENDS. RADAR AND SATELLITE
OBSERVATIONS INDICATE THAT PRECIP INTENSITY IS BEGINNING TO WANE
WITH TOPS WARMING AND ECHOES DIMINISHING. MODELS CONFIRM THIS AS
WELL WITH 18Z RUC UVM AND MOISTURE BOTH DECREASING IN DENDRITIC
GROWTH ZONE AROUND H6/H5 OR 300K ISENT SURFACE. THIS THINKING HAS
LEAD TO CATEGORICAL POPS WITH LITTLE ADDITIONAL ACCUMULATION THROUGH
00Z...FOLLOWED BY FURTHER DECREASE IN POPS AND NORTH TO SOUTH
COVERAGE LATER THIS EVENING. MOST LOCAL VISIBILITIES ARE NOW 1SM OR
GREATER. HEADLINES WERE TRIMMED TO 06Z THIS AFTERNOON AND COULD
VERY WELL NEED TO BE CANCELLED EVEN EARLIER THIS EVENING IF TRENDS
CONTINUE.
NEXT CONCERN TURNS TO CONDITIONS OVERNIGHT. VERY SHALLOW STRATUS
AND FOG WAS MAKING HEADWAY SOUTH EARLIER THIS AFTERNOON BUT THAT HAS
NOW ERODED. LOW LEVEL WINDS WILL LIKELY BE JUST STRONG ENOUGH TO
PRECLUDE WIDESPREAD DENSE FOG. HOWEVER 21Z SURFACE ANALYSIS SHOWS
LACK OF MUCH DRYING UPSTREAM SO HAVE MENTIONED PATCHY FOG FOR A
START IN CASE THIS MOISTURE AREA DOES INDEED FILL BACK IN AGAIN.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LOW WILL HAVE PUSHED FURTHER EAST FOR BEGINNING OF PERIOD...WITH
HIGH PRESSURE PUSHING IN. HAVE INCLUDED MENTION FOR FOG ACROSS THE
NORTH EARLY SUNDAY MORNING...AND SHOULD LIFT BY LATE MORNING.
COULD AGAIN SEE FOG EARLY MONDAY...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE MENTION ATTM. LOW OVER ROCKIES WILL DEEPEN...AND REMAIN
OVER ROCKIES THROUGH TUESDAY WITH SPLIT FLOW OVER REGION.
TEMPERATURES WILL WARM INTO MONDAY WITH WAA AND WEAK RIDGING OVER
IOWA.
STRONG WAVE WILL PUSH LOW OUT OF ROCKIES TUESDAY. THIS WILL BRING
A CHANCE FOR PRECIPITATION ACROSS IOWA. MODELS DO NOT HAVE GOOD RUN-
TO-RUN CONSISTENCY WITH TRACK OF LOW...BUT ARE BEGINNING TO PULL IT
FURTHER NORTH. HAVE INCLUDED SLIGHT CHANCE FOR PRECIPITATION
ACROSS SOUTHERN IOWA FOR TUESDAY INTO WEDNESDAY. WILL LIKELY SEE
RAIN CHANGING OVER TO SNOW. CURRENTLY...LIFT IS A BIT
LACKING...AND PRECIPITATION WILL LIKELY BE LIGHT.
BEHIND LOW...ANOTHER FRONTAL BOUNDARY WILL PUSH DOWN FROM CANADA.
ATTM APPEARS FROPA WILL BE DRY. MUCH COLDER AIR WILL WORK IN
BEHIND FRONT AND TEMPERATURES WILL GRADUALLY COOL TOWARDS END OF
PERIOD.
&&
.AVIATION...05/06Z
LARGE AREA OF STRATUS DROPPING SOUTH FROM MN NOW AND SOLID OVC003
WALL OF CLOUDS HEADING INTO THE AREA. ALREADY NEAR KMCW BY 06Z AND
EXPECTED TO HEAD TOWARD US 20 BY 08-09Z AT KALO AND KFOD. BY 12Z THE
AREA OF LOWER CLOUDS AND VSBY SHOULD BE NEARING KDSM AND THEN
BETWEEN 16-18Z FOR KOTM. WARM AIR ADVECTION ALOFT FROM THE NORTHERN
PLAINS AND SOUTHERN CANADA MAY ACT TO KEEP STRATUS GOING MOST OF THE
DAY ESPECIALLY GIVEN THE COLDER SFC TEMPS ACROSS MOST OF OUR AREA
NOW. WITH NEW SNOW PACK FROM I80 SOUTH TO BORDER...THIS AREA MIGHT
BE SUSCEPTIBLE TO THICK FOG DEVELOPMENT EITHER OVERNIGHT OR ON
SUNDAY AS WELL. NEXT FEW DAYS MAY THE REGION WILL HAVE ADDED
CHALLENGE OF BOUNDARY LAYER MOISTURE AND POSSIBLE ISSUES WITH FOG.
DIFFICULT TO TIME...BUT ONCE IT SETS UP...IT MAY STICK AROUND UNTIL
STRONGER SFC WINDS RETURN MONDAY NIGHT OR TUESDAY. HAVE PASSED
DETAILS ALONG TO NIGHT SHIFT FOR NEXT PACKAGE. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
SHORT TERM...SMALL/REV
LONG TERM...AWB
AVIATION...REV
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1100 PM CST SAT FEB 4 2012
.UPDATE PUBLIC DISCUSSION...
.SHORT TERM /TONIGHT/...
...REMAINDER OF WARNINGS/ADVISORIES HAVE BEEN CANCELLED. STORM NOW
SOUTH OF AREA AND CONDITIONS CONTINUE TO IMPROVE.
...CONTINUE TO TRIM BACK ADVISORY. EASTERN AREAS OF LIGHT SNOW
NEARLY OVER AND SOUTHWEST CONTINUES LIGHT. WARNING AREA STILL
RECEIVING SOME ADDITIONAL LIGHT SNOW. ALL WILL EXPIRE AT 06Z.
NEXT ISSUE IS FOG AND LOW STRATUS. EXPECTING LOW STRATUS AND FOG TO
OVERTAKE NORTHERN BORDER COUNTIES NEAR MN BORDER BY 06Z AND
TRANSLATE SOUTH TO NEAR DES MOINES BY 12Z. HAVE ADDED AREAS FOG
NORTH AND MAINTAIN PATCHY FOG SOUTH. IF SKIES CLEAR AND FOG GETS A
FOOTHOLD...MAY BE SOME DENSE FOG. DIFFICULT TO DECIDE WHAT AREAS
MIGHT BE AT RISK FOR THAT...GIVEN APPROACHING CLOUDS. UPSTREAM
VSBYS LAST NIGHT WERE AT OR ABOVE 1/2SM SO...MIGHT NOT BE A MAJOR
ISSUE WITH THE EXCEPTION OF FROSTY ROAD SURFACES. WILL NEED TO
MONITOR THROUGH THE NIGHT.
HAVE TRIMMED BACK WINTER STORM WARNING WITH THE EXCEPTION OF WHERE
SNOW STILL FALLING IN SW IA. LEAVING ADVISORY AS IS...DUE TO BAND OF
SNOW STILL OCCURRING IN DEF ZONE OVER THE SOUTHEAST. MONITORING AREA
FOR FOG DEVELOPMENT LATE TONIGHT. ADVECTION FOG OVER MN AND
POTENTIAL FOR RADIATION FOG OVER IOWA MAY COMPLICATE TRAVEL
OVERNIGHT AND EARLY SUNDAY MORNING.
.PREVIOUS SHORT TERM /TONIGHT/...
PRIMARY CONCERNS REMAIN SNOW TRENDS. RADAR AND SATELLITE
OBSERVATIONS INDICATE THAT PRECIP INTENSITY IS BEGINNING TO WANE
WITH TOPS WARMING AND ECHOES DIMINISHING. MODELS CONFIRM THIS AS
WELL WITH 18Z RUC UVM AND MOISTURE BOTH DECREASING IN DENDRITIC
GROWTH ZONE AROUND H6/H5 OR 300K ISENT SURFACE. THIS THINKING HAS
LEAD TO CATEGORICAL POPS WITH LITTLE ADDITIONAL ACCUMULATION THROUGH
00Z...FOLLOWED BY FURTHER DECREASE IN POPS AND NORTH TO SOUTH
COVERAGE LATER THIS EVENING. MOST LOCAL VISIBILITIES ARE NOW 1SM OR
GREATER. HEADLINES WERE TRIMMED TO 06Z THIS AFTERNOON AND COULD
VERY WELL NEED TO BE CANCELLED EVEN EARLIER THIS EVENING IF TRENDS
CONTINUE.
NEXT CONCERN TURNS TO CONDITIONS OVERNIGHT. VERY SHALLOW STRATUS
AND FOG WAS MAKING HEADWAY SOUTH EARLIER THIS AFTERNOON BUT THAT HAS
NOW ERODED. LOW LEVEL WINDS WILL LIKELY BE JUST STRONG ENOUGH TO
PRECLUDE WIDESPREAD DENSE FOG. HOWEVER 21Z SURFACE ANALYSIS SHOWS
LACK OF MUCH DRYING UPSTREAM SO HAVE MENTIONED PATCHY FOG FOR A
START IN CASE THIS MOISTURE AREA DOES INDEED FILL BACK IN AGAIN.
.LONG TERM /SUNDAY THROUGH FRIDAY/...
LOW WILL HAVE PUSHED FURTHER EAST FOR BEGINNING OF PERIOD...WITH
HIGH PRESSURE PUSHING IN. HAVE INCLUDED MENTION FOR FOG ACROSS THE
NORTH EARLY SUNDAY MORNING...AND SHOULD LIFT BY LATE MORNING.
COULD AGAIN SEE FOG EARLY MONDAY...BUT NOT ENOUGH CONFIDENCE TO
INCLUDE MENTION ATTM. LOW OVER ROCKIES WILL DEEPEN...AND REMAIN
OVER ROCKIES THROUGH TUESDAY WITH SPLIT FLOW OVER REGION.
TEMPERATURES WILL WARM INTO MONDAY WITH WAA AND WEAK RIDGING OVER
IOWA.
STRONG WAVE WILL PUSH LOW OUT OF ROCKIES TUESDAY. THIS WILL BRING
A CHANCE FOR PRECIPITATION ACROSS IOWA. MODELS DO NOT HAVE GOOD RUN-
TO-RUN CONSISTENCY WITH TRACK OF LOW...BUT ARE BEGINNING TO PULL IT
FURTHER NORTH. HAVE INCLUDED SLIGHT CHANCE FOR PRECIPITATION
ACROSS SOUTHERN IOWA FOR TUESDAY INTO WEDNESDAY. WILL LIKELY SEE
RAIN CHANGING OVER TO SNOW. CURRENTLY...LIFT IS A BIT
LACKING...AND PRECIPITATION WILL LIKELY BE LIGHT.
BEHIND LOW...ANOTHER FRONTAL BOUNDARY WILL PUSH DOWN FROM CANADA.
ATTM APPEARS FROPA WILL BE DRY. MUCH COLDER AIR WILL WORK IN
BEHIND FRONT AND TEMPERATURES WILL GRADUALLY COOL TOWARDS END OF
PERIOD.
&&
.AVIATION...05/00Z
SYSTEM BEGINNING TO WEAKEN AS DEF ZONE LOSING SUPPORT FROM MAIN
UPPER LEVEL LOW PULLING OFF THE THE SOUTHEAST OF IA THIS EVENING.
CONSEQUENTLY...CIGS AND VSBYS WILL CONTINUE TO IMPROVE FOR THE SHORT
TERM WITH GENERALLY VFR FOR A SHORT PERIOD OF TIME. HOWEVER...BY MID
TO LATE EVENING AFT 05Z FOG POTENTIAL WILL INCREASE. FRESH SNOW
COVER AND CLEARING SKIES ALONG WITH AMPLE MOISTURE IN THE BOUNDARY
LAYER MAY LEAD TO FOG. QUESTION ABOUT MOISTURE DEPOSITION OR IF IT
REMAINS SUSPENDED. WINDS WILL REMAIN IN THE 7 TO 8KT RANGE...SO THIS
MAY HELP THE AIRMASS REMAIN MIXED AS THE ENTIRE COLUMN COOLS TO
SATURATION. THOUGH CONFIDENCE LOW...MAY NEED TO UPDATE FOR LIFR FOG
AND OR CIGS LATER THIS EVENING IF TRENDS FOR THICK FOG ARE
CONFIRMED. THEN...PERIOD OF MOST CONCERN WOULD SHIFT TO 10-15Z
SUNDAY MORNING. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
SHORT TERM...SMALL/REV
LONG TERM...AWB
AVIATION...REV
AREA FORECAST DISCUSSION
NWS TOPEKA KS
1122 PM CST SAT FEB 4 2012
...UPDATE TO AVIATION...
&&
.AVIATION...
LIGHT SNOW AND IFR CONDITIONS TO CONTINUE AT TOP AND MHK FOR THE
NIGHT...WITH LIFR CIGS AT FOE. SKIES CLEAR QUICKLY AFTER SUNRISE
AND LIGHT NORTHWEST WINDS CONTINUE THROUGH SUNDAY. 67
&&
.PREV DISCUSSION...
/ISSUED 308 PM CST SAT FEB 4 2012/
SHORT RANGE FORECAST (TONIGHT THROUGH SUNDAY)...
UPPER LEVEL LOW PRESSURE SYSTEM IS CURRENTLY CENTERED ROUGHLY OVER
KFNB AS OF 20Z PER WATER VAPOR IMAGERY AND RUC UPPER LEVEL ANALYSIS.
THE TROUGH HAS BEEN STEADY STATE REGARDING INTENSITY THROUGHOUT THE
DAY...MEANING IT HAS NOT UNDERGONE SIGNIFICANT STRENGTHENING OR
WEAKENING. WATER VAPOR IMAGERY ALSO INDICATING A SLOT OF DRY AIR
STRETCHING FROM SOUTH CENTRAL IOWA SOUTHWESTWARD TO THE
OKLAHOMA/TEXAS PANHANDLES. THIS DRY SLOT HAS CAUSED THE MID LEVELS
TO BECOME RATHER DRY...WHICH HAS CREATED A DRIZZLY AFTERNOON ACROSS
MUCH OF NORTHEAST KANSAS..ESPECIALLY EAST OF A MARYSVILLE TO TO
ABILENE LINE. WEST AND NORTH OF THAT LINE VERY LIGHT SNOW SHOWERS
ARE PERSISTING AS THE UPPER LOW RESIDES OVER THE AREA. WITH THE LACK
OF ANY APPRECIABLE MID LEVEL FRONTOGENESIS AND MEAGER OVERALL LIFT
INDICATED BY OMEGA VALUES PROGGED TO BE IN THE -2 TO -4 MICROBAR/SEC
RANGE...DO NOT EXPECT MUCH MORE SNOW TO FALL ACROSS ANY OF THE
FORECAST AREA DURING THE REMAINDER OF THE AFTERNOON AND EVENING.
ACROSS FAR EASTERN KANSAS...EXPECT CLOUDY CONDITIONS TO REMAIN WITH
PERIODS OF LIGHT RAIN AND PATCHY DRIZZLE. LATER THIS AFTERNOON
FORECAST MODELS HINT AT SOME DEEPER MOISTENING OF THE ATMOSPHERIC
COLUMN WHICH COULD ALLOW FOR SOME LIGHT SNOW SHOWERS ALONG THE
INTERSTATE 70 CORRIDOR LATER TONIGHT. SNOW AMOUNTS WILL BE PRETTY
MEAGER WITH ONLY A TENTH OR TWO OF AN INCH OF SNOW. EXPECT PRECIP TO
COME TO A GRADUAL END BY LATE SATURDAY NIGHT INTO EARLY SUNDAY
MORNING AS THE UPPER SYSTEM COMPLETELY MOVES OUT OF THE AREA. EXPECT
SKIES TO ALSO GRADUALLY CLEAR OVERNIGHT AND THROUGHOUT THE DAY ON
SUNDAY. MADE VERY FEW CHANGES TO TEMPERATURES FOR THE OVERNIGHT
HOURS SATURDAY AND DAYTIME PERIOD ON SUNDAY...BUT DID LOWER TEMPS ON
THE ORDER OF 3 TO 5 DEGREES WHERE THE MOST SNOW FELL...NAMELY ACROSS
CLOUD...REPUBLIC...WASHINGTON...AND MARSHALL COUNTIES.
JL
MONDAY AND MONDAY NIGHT...SURFACE HIGH PRESSURE AND AMPLIFYING
SOUTHERN RIDGE WILL KEEP CONDITIONS TRANQUIL ACROSS THE PLAINS
MONDAY AND MONDAY EVENING. SOUTHWESTERLY FLOW WILL RETURN TO THE
REGION ON MONDAY ON THE WEST SIDE OF THE SURFACE RIDGE ALONG WITH
WEAK WAA. MODELS PROG CANADIAN TROF TO SWEEP CUTOFF LOW OVER THE
WASATCH RANGE MONDAY AFTERNOON...AND OUT ONTO THE PLAINS BY MONDAY
NIGHT. AFTERNOON HIGHS ON MONDAY WILL BE SLIGHTLY ABOVE NORMAL IN
THE MID TO UPPER 40`S DUE TO THE WEAK WAA. THE NORTHWESTERN
COUNTIES WILL LIKELY REMAIN IN THE 30`S WITH THE SNOW COVER.
TUESDAY AND TUESDAY NIGHT...COLD FRONT EXPECTED TO SWEEP THROUGH THE
CWA TUESDAY MORNING. MID LEVEL MOISTURE ADVECTS INTO THE AREA FROM
THE WEST...WHERE LOW LEVEL MOISTURE ADVECTS IN WITH THE COLD AIR
BEHIND THE 850MB FRONT MID DAY TUESDAY. BUMPED UP POPS A BIT
TUESDAY MORNING AND AFTERNOON WITH SLOWLY GROWING CONFIDENCE THAT
PRECIP WILL OCCUR ON TUESDAY. ECMWF AND GFS HAD DIVERGED WITH THE
AREAS OF GREATEST QPF. GFS WAS MUCH FURTHER NORTH AND AWAY FROM BEST QG
FORCING SUPPORT OVER SOUTHERN KANSAS AND OKLAHOMA. ECMWF HAD BEEN
IN BETTER ALIGNMENT WITH THE QG FORCING. HOWEVER...LATEST ECMWF
ALIGNS IN BETTER AGREEMENT TO THE GFS THAN PREVIOUS RUNS...AND GIVEN
THE SIGNIFICANT PV ANOMALY PROGGED TO TRAVERSE EASTERN KANSAS
TUESDAY AFTERNOON AND EVENING...THINKING IS THAT ECMWF MAY BE ON
TRACK WITH HIGHER QPF AMOUNTS OVER EASTERN KANSAS THAN PREVIOUSLY
THOUGHT. FOR NOW...GIVEN INCONSISTENCY IN THE MODELS...BUMPED POPS
UP ONLY SLIGHTLY. NEXT QUESTION WILL BE PRECIP TYPE. FORECAST
SOUNDINGS INDICATE SFC TEMPS WILL BE CLOSE TO THE FREEZING MARK AT
THE SURFACE WITH DEPTHS OF ABOUT 400 FEET BEFORE SUB-ZERO
TEMPERATURES ARE REACHED ALOFT. HOWEVER...GFS DEPICTS 500MB DRY
SLOT NEAR THE ICE CRYSTAL GROWTH ZONE. IF ENOUGH DRY AIR WORKS INTO
THE GROWTH ZONE TO INHIBIT ICE CRYSTAL GROWTH...MAY ONLY SEE RAIN
INSTEAD OF ANY SNOW. LIFT IS NOT ABUNDANT WITH THIS SYSTEM...AND
MOST OF THE QG FORCING IS STILL PROGGED TO REMAIN SOUTH OF THE
CWA...BUT IF THE PV ANOMALY IS AS STRONG AS DEPICTED COUPLED WITH
MODERATE MOISTURE ADVECTION...COULD POSSIBLY SEE A FEW HUNDREDTHS OF
AN INCH OF PRECIPITATION.
EXTENDED...SYSTEM EXITS TUESDAY NIGHT INTO WEDNESDAY WITH THE NEXT
WAVE EXPECTED WEDNESDAY EVENING. THIS SYSTEM ALSO PROGGED TO HAVE A
STRONG PV ANOMALY...AND ECMWF IS PICKING UP ON SOME PRECIPITATION
OVER NORTHEAST KANSAS. ATTM...LEFT THE EXTENDED DRY GIVEN THE
VARIABILITY IN THE MODEL RUNS AND THE FAIRLY DRY ATMOSPHERE IN PLACE
THURSDAY AFTERNOON. NEXT SYSTEM AND COLD FRONT EXPECTED THURSDAY EVENING AND
HIGH PRESSURE RETURNING ON FRIDAY AND SATURDAY. TEMPERATURES
WISE...SHOULD SEE HIGHS NEAR NORMAL WITH LOWS IN THE 20`S AND HIGHS
IN THE UPPER 30`S AND LOW 40`S. EXCEPTION WILL BE WITH THE SNOW
PACKED AREAS WITH HIGHS IN THE 30`S AND LOWS IN THE TEENS.
BYRNE
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
438 AM EST SUN FEB 5 2012
.SYNOPSIS...
ANY REMAINING MIX OF LIGHT RAIN AND SNOW WILL END THIS MORNING, AS
UPPER LEVEL DISTURBANCE EXITS EAST. HIGH PRESSURE WILL THEN FOLLOW
TO BRING SOME SUN BY AFTERNOON, AND AGAIN ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT RADAR DATA TRENDS AND HRRR AND WRF-NMM MODEL OUTPUT
CONTINUE TO SHOW ANY LIGHT MIX OF RAIN AND WET SNOW WILL END
BEFORE MID-MORNING, AS AN UPPER LEVEL JETSTREAM MAX EXITS EAST.
THERE MAY BE A SMALL ACCUMULATION OF WET SNOW OVER THE HIGHER
MOUNTAINS.
RECENT SURFACE DATA SHOWS SIGNS THAT THE LOW CLOUDS RESULTING IN
AREAS OF FOG OVER THE HIGHER PA-WV-MD MOUNTAINS, HAS BEGUN TO
LIFT. SO EXPECT ANY REMAINING HIGHER ELEVATION FOG TO HAVE ENDED
BY 9 AM.
PER TRENDS IN RECENT SATELLITE DATA AND SUPPORT FROM RECENT HRRR
AND NAM MODEL OUTPUT, EXPECT CLOUDS TO ALSO DECREASE, NORTH TO
SOUTH, THIS MORNING, YIELDING A DECENT AMOUNT OF SUNSHINE THIS
AFTERNOON.
HAVE CONTINUED TO FINE TUNE TEMPERATURE FORECAST PER RECENT HRRR
AND GFS LAMP MODEL OUTPUT. EXPECT AFTERNOON HIGHS TO BE 2 TO 5
DEGREES WARMER THAN NORMAL, WHICH IS ALSO SUPPORTED BY RECENT NAM
AND GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
BLEND OF RECENT SREF AND ECMWF MODEL OUTPUT SHOWS SPRAWLING HIGH
PRESSURE, EXTENDING FROM THE PLAINS TO THE APPALACHIANS, WILL
PROVIDE NO MORE THAN SCATTERED CLOUDS ACROSS THE UPPER OHIO VALLEY
TONIGHT INTO TUESDAY. THIS WILL MAINTAIN MILD CONDITIONS, WITH
LOWS AND HIGHS GENERALLY 5 TO 8 DEGREES WARMER THAN NORMAL.
MODELS THEN SHOW STRONG HIGH PRESSURE SPREADING SOUTHEASTWARD FROM
THE CANADIAN PLAINS. THIS WILL PUSH A COLD FRONT SOUTHWARD THROUGH
THE UPPER OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE FRONT MAY
HAVE LITTLE MOISTURE TO INGEST, SO MAINTAINED A SLIGHT CHANCE OF
PREFRONTAL SHOWERS TUESDAY NIGHT, AND A CHANCE OF POSTFRONTAL SHOWERS
WEDNESDAY.
THE PRECIPITATION TYPE WILL BE A MIX OF RAIN AND SNOW, AS SURFACE
LAYER TEMPERATURES WILL STRADDLE THE FREEZING POINT. THIS IDEA IS
SUPPORTED BY RECENT GFS AND NAM MOS WHICH SHOW TEMPERATURES TO
LOWER TO SEASONABLE LEVELS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A DEEP UPPER
LOW PASSING EASTWARD THROUGH EASTERN CANADA LATE WEEK. HENCE
EXPECT A COLD FRONT, WITH A MIX OF RAIN AND SNOW SHOWERS, TO PASS
THROUGH THE UPPER OHIO VALLEY AROUND FRIDAY. FOR NOW HAVE
CONTINUED FORECAST OF NEAR-SEASONABLE POSTFRONTAL TEMPERATURES FOR
SATURDAY. HOWEVER, RECENT NAEFS MEDIAN VALUES AND GFS MOS SUGGEST
TEMPERATURES SATURDAY COULD BECOME 5 TO 10 DEGREES COLDER THAN
NORMAL.
&&
.AVIATION /09Z SUNDAY THROUGH THURSDAY/...
IFR CONDITIONS IN FOG AND STRATUS MAY REMAIN ACROSS KMGW AND THE
MOUNTAINS EAST INTO MID MORNING AS LOW LEVEL MOISTURE FROM
PREVIOUS LIGHT MIXED PRECIPITATION WILL BE TRAPPED UNTIL SURFACE
HIGH CAN MIX BOUNDARY LAYER.
FARTHER NORTH, ACROSS THE KZZV-KPIT-KLBE CORRIDOR, HAVE LOWERING
CONFIDENCE THAT CURRENT MVFR VISIBILITY RESTRICTIONS BY FOG WILL
DETERIORATE TO IFR THIS MORNING. IF STRATUS FAILS TO DEVELOP,
VISIBILITIES WILL IMPROVE TO VFR BY LATE MORNING.
NORTHERN TERMINALS, KFKL AND KDUJ, WILL STAY VFR THROUGH PERIOD. WINDS
WILL BE LIGHT NORTHERLY INTO THE AFTERNOON.
OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
GENERAL VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY. A SERIES OF
SHORT WAVES MAY BRING RESTRICTIONS AT TIMES IN SNOW SHOWERS
WEDNESDAY INTO THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
1247 AM EST SUN FEB 5 2012
.SYNOPSIS...
EASTBOUND UPPER LEVEL DISTURBANCE MAY PRODUCE A MIX OF LIGHT RAIN
AND SNOW OVERNIGHT FOR AREAS SOUTH OF PITTSBURGH. HIGH PRESSURE
WILL FOLLOW TO BRING SOME SUN SUNDAY AFTERNOON AND AGAIN ON MONDAY.
&&
.NEAR TERM /THROUGH TODAY/...
RECENT RADAR DATA TRENDS AND HRRR AND WRF-NMM MODEL OUTPUT
CONTINUE TO SHOW AN UPPER LEVEL JETSTREAM MAX WILL CAUSE A LIGHT
MIX OF RAIN AND SNOW OVERNIGHT, UNTIL IT EXITS EAST SUNDAY
MORNING. THERE MAY BE A SMALL ACCUMULATION OF WET SNOW OVER THE
HIGHER MOUNTAINS.
RECENT SURFACE DATA SHOWS LOW CLOUDS RESULTING IN AREAS
OF FOG OVER THE HIGHER PA-WV-MD MOUNTAINS, WHICH NAM MODEL
PROFILES SHOW MAY NOT LIFT UNTIL SUNDAY MORNING.
ADJUSTED TEMPERATURES OVERNIGHT 1-2 DEGREES WARMER, BASED ON
RECENT HRRR AND GFS LAMP MODEL OUTPUT. EXPECTING LEFTOVER LOW CLOUDS
SUNDAY MORNING, HAVE SLOWED WARM UP, AND HAVE ALSO CUT HIGHS
SUNDAY AFTERNOON BY 1-2 DEGREES, WHICH HAS SOME SUPPORT FROM
RECENT GFS LAMP.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...
DRY WEATHER AND ABOVE NORMAL TEMPERATURES ARE FORECAST FOR THE
SHORT TERM AS A WEAK RIDGE ALOFT SLIDES EASTWARD OVER THE REGION
AND A SURFACE HIGH BUILDS INTO THE UPPER OHIO VALLEY. MAXIMUM
TEMPERATURES SHOULD REACH WELL INTO THE 40S MONDAY AFTERNOON AND
RANGE FROM THE UPPER 30S TO MID 40S TUESDAY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
A SERIES OF SHORT WAVES THROUGH THE EXTENDED PERIOD WILL
BRING UNSETTLED WEATHER WITH A CHANCE OF RAIN OR SNOW SHOWERS EACH
DAY. THE TEMPERATURES WILL BE NEAR OR A BIT ABOVE NORMAL THROUGH
THE PERIOD. THE SYSTEMS WILL BE MOVING RAPIDLY IN THE WEAK WEST
NORTHWEST FLOW ALOFT WITH LITTLE AVAILABLE MOISTURE. AS A RESULT
PRECIPITATION WILL BE LIMITED THROUGH THE PERIOD.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
IFR CONDITIONS IN FOG AND STRATUS EXPECTED INTO MID MORNING FROM
PITTSBURGH SOUTH AS LOW LEVEL MOISTURE FROM PREVIOUS MELTED SNOWFALL
WILL BE TRAPPED ACROSS REGION UNTIL SURFACE HIGH CAN MIX BOUNDARY
LAYER. CURRENT MVFR AT KPIT AND KAGC SHOULD DETERIORATE BY 08Z TO
IFR OR LOWER.
NORTHERN TERMINALS WILL STAY VFR THROUGH PERIOD. BIT OF MIXED
RAIN AND SNOW WILL PASS REGION EARLY AS UPPER LEVEL TROUGH CROSSES
REGION. HIGH PRESSURE RIDGE WILL BUILD ACROSS FROM THE WEST BY
MIDDAY WITH ENOUGH MIXING TO BRING ALL SITES TO VFR. WINDS WILL BE
LIGHT NORTHERLY INTO THE AFTERNOON.
OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
GENERAL VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY. A SERIES OF
SHORT WAVES MAY BRING RESTRICTIONS AT TIMES IN SNOW SHOWERS
WEDNESDAY INTO THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
434 AM EST SUN FEB 5 2012
.SYNOPSIS...
00Z RAOBS SHOW DECAYING UPR LOW OVR KS/MO WHILE LARGER SCALE RIDGE
IS LOCATED FM WEST CONUS INTO WESTERN CANADA. PRIMARY TROUGHING IS
ORIENTED FM NORTHERN CANADA INTO QUEBEC AND NEW BRUNSWICK. COLDEST
AIR BY FAR IS LOCATED OVR FAR NORTHERN SECTIONS OF CANADA IN VCNTY
OF POLAR VORTEX. OTHERWISE...MOST OF CANADA AND THE CONUS FOR THAT
MATTER IS AWASH IN CONTINUAL FLOW OF MILD PACIFIC AIR. THIS WEEK
RIDGE IS EXPECTED TO BECOME MORE MERIDIONAL FM WESTERN CONUS INTO
ALASKA. RESULT IS EASTERN CANADA TROUGH TO SETTLE TOWARD GREAT LAKES
AND NORTHEAST CONUS. FIRST PUSH OF COOLER AIR ARRIVES ACROSS UPR
LAKES LATE MONDAY INTO TUESDAY. ANOTHER SHOT OF MUCH COLDER AIR IS
POSSIBLE LATE THIS WEEK INTO FIRST PART OF NEXT WEEKEND AS PORTION
OF POLAR VORTEX TRIES TO DISLODGE AND COME INTO THE CONUS. PATTERN
DOES NOT SUGGEST MUCH IN WAY OF OPPORTUNITY FOR LARGE SCALE WINTER
SYSTEMS. MAIN SNOWFALL THROUGH PERIOD WILL COME VIA LK EFFECT.
&&
.SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
IN THE NEAR TERM...SFC RIDGE OVR PLAINS BEGINS TO EXPAND INTO UPR
LAKES. RUC13 HAS MUCH BETTER HANDLE ON CURRENT STRATUS THAN 00Z
NAM. PER RUC13 OUTPUT AND RAOBS...MOISTURE ADVECTION IN THE CLOUD
BEARING LAYER IS NEUTRAL SO EXPECT STRATUS BASED AROUND 925MB TO
PERSIST OVR CNTRL AND EASTERN CWA. TEMPS WILL REMAIN IN THE UPR 20S
TO LOWER 30S...EXCEPT STAYING IN THE TEENS OVR FAR WEST.
TODAY AND TONIGHT...EXPECT STRATUS TO CLEAR FM WEST TO EAST THIS
MORNING AS 925MB WINDS TURN WESTERLY ALLOWING LOWER 925MB DWPNTS TO
ADVECT INTO UPR LAKES. ONCE LOW CLOUDS DEPART...MIXING HEIGHTS BUILD
BENEATH MOSTLY SUNNY SKIES /THOUGH MAY SEE SCT-BKN MID CLOUDS INTO
EARLY AFTN NCNTRL AND EAST BASED ON CURRENT TRAJECTORIES OF CLOUDS
DROPPING ACROSS ONTARIO/. MODEL PROFILES FM BUFKIT INDICATE MIXING
ONLY TO 925MB BUT GIVEN EXPECTED INSOLATION...AND SEEING THAT LOW-
LEVELS MIXED AOA 900MB ON SATURDAY PER KGRB 00Z SOUNDING...WILL OPT
FOR MORE MIXING AND HIGHER TEMPS. BLEND OF 900MB-850MB MIXING HEIGHT
SUPPORTS HIGHS WELL INTO THE 40S AND MAYBE EVEN NEAR 50 DEGREES...
ESPECIALLY IN DOWNSLOPE AREAS OF CNTRL CWA /BARAGA TO MARQUETTE AND
SOUTH TO ESCANABA AND MENOMINEE/. BASED ON HOW WARM TEMPS WERE
YDY...MAY COME CLOSE TO THE RECORD HIGH OF 50 DEGREES FOR WFO
MARQUETTE /2005/. THE WARM DAY WILL TRANSLATE TO WELL ABOVE NORMAL
TEMPS FOR TONIGHT. WARMING WILL BE MOST PRONOUNCED NEAR LK SUPERIOR
SHORE WITH WEST WINDS STIRRING ALL NIGHT AHEAD OF COLD FRONT
APPROACHING FM THE NORTH. BASED ON UPSTREAM READINGS THIS MORNING
AHEAD OF COLD FRONT...WINDS MAY STILL BECOME LIGHT IN THE INTERIOR SO
KEPT LOWS AROUND 20F INLAND WEST.
MONDAY...COLD FRONT REACHES KEWEENAW BTWN 15-18Z...THEN SWINGS
THROUGH FM NORTH TO SOUTH THROUGH THE DAY OVR REST OF CWA. RETAINED
FALLING TEMP IDEA FM PREVIOUS SHIFT...ESPECIALLY OVER THE NORTH HALF
OF THE CWA IN THE AFTN. WEST FLOW AND H9 TEMPS NEAR 0C AHEAD OF FRONT
SHOULD ALLOW TEMPS OVR FAR SCNTRL TO CLIMB INTO THE LOW 40S AT KMNM...
BEFORE FALLING OFF INTO THE LOWER 30S LATE. TEMPS WILL FALL FM THE
LOWER 30S INTO THE LOWER 20S BY SUNSET OVR REST OF THE CWA. SEEMS
THAT PCPN CHANCES WILL BE FAIRLY LIMITED UNTIL MONDAY NIGHT. FCST
SOUNDINGS FM NAM/GFS SUGGEST INCREASING STRATOCU CLOUDS MORE THAN
ANYTHING ELSE. MOIST LAYER FCST TO REACH -10C LATE AFTN INTO EARLY
EVENING SO COULD SEE SNOW GRAINS OR FLURRIES LATE IN THE DAY OVR
HIGHER TERRAIN OF NW CWA.
MONDAY NIGHT...COOLING CONTINUES AT 925-850MB WITH FCST SOUNDINGS
INDICATING MOISTURE THROUGH AROUND 5KFT BY 06Z-12Z IN A WEAKLY
CYCLONIC NORTHERLY FLOW REGIME. UNIDIRECTIONAL FLOW THROUGH
850MB/5KFT WITH WIND SPEEDS LESS THAN 20 KTS SHOULD HELP LK EFFECT
ORGANIZE LATE EVENING INTO OVERNIGHT HOURS. DESPITE SUBSIDENCE/DRYING
ABOVE INVERSION AT H85...MAJORITY OF LAKE CONVECTIVE LAYER IS WITHIN
MOST IDEAL SNOW DENDRITIC GROWTH ZONE WITH TEMPS -12C TO -18C. ECMWF
IS ON THE WARM END WHILE CANADIAN INDICATES H85 TEMPS DOWN NEAR -20C
BY LATE MONDAY NIGHT. CERTAINLY HAVE SEEN MORE IMPRESSIVE LK EFFECT
SETUP BUT DOES SEEM THAT NRLY WINDS...LOW-LEVEL CONVERGENCE...AND
FAVORABLE MOISTURE WITHIN THE DGZ JUSTIFIES INCREASING POPS OVR FAR
WEST AND ALSO OVR MUCH OF MARQUETTE AND ALGER COUNTIES. A FEW INCHES
OF SNOW IS NOT OUT OF QUESTION MONDAY NIGHT AIDED BY HIGH SLR/S AND
INCREASING FLUFFINESS TO THE SNOW. EXPECT MINS INTO THE SINGLE
DIGITS OVR THE INTERIOR WEST WITH READINGS IN THE TEENS FOR OTHER
AREAS.
.LONG TERM /12Z TUE THRU SAT/...
TUE...ALTHOUGH A SHRTWV WL BE PUSHING THRU THE UPR GRT LKS ON TUE
MRNG FOLLOWING THE SHARP COLD FROPA MON NGT...LATEST MODELS RUNS
HAVE CONTINUED TREND TOWARD RISING HGTS SHARPLY IN THE AFTN WITH
VIGOROUS DNVA/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE WAKE OF THE
SHRTWV PASSAGE RESULTING IN SHARP ACYC FLOW BY 00Z WED. ONGOING LES
OVER MAINLY THE N WIND SN BELTS IN THE MRNG WITH H85 TEMPS FCST BTWN
-14C BY THE ECMWF TO AS LO AS -20C BY THE CNDN MODEL WL SUPPORT
LIKELY POPS IN THE FAVORED SN BELTS WITH INVRN HGTS ARND 4K FT AGL
AT 12Z. BUT THE SHSN WL TEND TO DIMINISH STEADILY THRU THE DAY
ESPECIALLY OVER THE W AS H85 TEMPS ARE FCST TO RISE UP AS HI AS -10C
BY THE ECMWF BY 00Z WED. THE 00Z GFS INDICATES THE STRONG SUBSIDENCE
WL CAUSE THE INVRN BASE TO SINK TO 2K FT AGL BY 00Z WED...ENDING ANY
SGNFT SHSN BY LATE IN THE DAY AS PWAT SINKS BLO 0.10 INCH.
TUE NGT...UNDER RISING HGTS...SHRTWV RDG IS PROGGED TO BLD SLOWLY
THRU THE UPR GRT LKS. WITH PWAT FCST AS LO AS 0.10 INCH/MOCLR SKIES
AND LGT WINDS...EXPECT TEMPS OVER THE INTERIOR SCNTRL TO SINK AOB
THE LO END OF GUIDANCE. READINGS NEAR LK SUP WL BE BUOYED A BIT BY A
STRONGER W WIND TO THE N OF THE SFC RDG AXIS ORIENTED THRU NRN WI
INTO NRN LWR MI.
EXTENDED...HI PRES RDG WL DROP INTO THE OH VALLEY ON WED WITH A DRY
WLY FLOW DOMINATING AND TEMPS A BIT ABV NORMAL. NEXT SHRTWV WL
IMPACT THE UPR LKS ON THU. THE 00Z GFS/CNDN MODELS ARE IN FAIRLY
GOOD AGREEMENT SHOWING A STRONGER DISTURBANCE/SFC LO MOVING THRU THE
UPR LKS. WHILE THE 12Z ECMWF RUN SHOWED A SIMILAR SCENARIO...THE 00Z
RUN HAS BACKED OFF ON THE INTENSITY OF THIS DISTURBANCE...CONTINUING
A TREND OF MODEL INCONSISTENCIES ON THE HANDLING OF THIS SHRTWV. SO
WENT NO HIER THAN CHC POPS FOR SN ON THU. WITH THE ARRIVAL OF COLDER
AIR IN THE WAKE OF THE SHRTWV PASSAGE /H85 TEMPS AS LO AS -26C PER
THE 00Z GFS BUT ONLY -20C PER THE ECMWF/... EXPECT LES MAINLY IN THE
NW WIND SN BELTS INTO FRI NGT. THE ARRIVAL OF HI PRES ON SAT WL
CAUSE THE LES TO DIMINISH. EXPECT TEMPS TO RUN AOB NORMAL THU NGT
INTO SAT.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
MVFR CLOUDS AT ALL THE TAF SITES SHOULD LIFT AND DECREASE BY LATE
MORNING AS A HIGH PRESSURE RIDGE MOVES ACROSS THE AREA AND NRLY
WINDS BACK TO THE WEST. SCT-BKN MID CLOUDS THEN SLIDE THROUGH INTO
MID AFTN. CONDITIONS WILL BE VFR AFTER THE LOWER CLOUDS CLEAR THIS
MORNING.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
NORTHERLY WINDS TURN WEST AND INCREASE TO 30 KTS THIS AFTERNOON AND
EVENING AHEAD OF COLD FRONT DROPPING SOUTH ACROSS ONTARIO. MAY SEE
GALE GUSTS TO 35 KTS DUE TO COASTAL CONVERGENCE ALONG TIP OF
KEWEENAW PENINSULA. WINDS BECOME NORTHERLY ON MONDAY AFTERNOON IN
WAKE OF COLD FRONT. GALE GUSTS TO 35 KTS POSSIBLE MONDAY EVENING
OVER NORTH AND EAST...BUT THEN WINDS DIMINISH TO LESS THAN 25 KTS
LATER MONDAY NIGHT AS HIGH PRESSURE RIDGE QUICKLY BUILDS INTO UPR
LAKES REGION. A RISK OF HEAVY FREEZING SPRAY MONDAY NIGHT OVR
NORTHERN SECTIONS AS TEMPS DROP TOWARD ZERO.
THE ARRIVAL OF THE HI PRES RDG WILL CAUSE DIMINISING WINDS ON
TUE/TUE NIGHT...BUT A STRONGER WSW FLOW UP TO 25-30 KTS WILL DEVELOP
ON WED AS THIS RDG SINKS TO THE S. THE HIGHEST WINDS ARE MOST LIKELY
BETWEEN THE KEWEENAW AND ISLE ROYALE WHERE TERRAIN INFLUENCES TEND
TO ENHANCE THIS FLOW. FOLLOWING THE PASSAGE OF A LO PRES ON THU...
PLAN ON A STRONGER NNW FLOW OF COLDER AIR. THERE ARE MODEL
DIFFERENCES ON THE FORECAST INTENSITY OF THIS LO...AND GALES WOULD
NOT BE OUT OF THE QUESTION IF THE DEEPER SCENARIO VERIFIES. WITH THE
POTENTIAL ARRIVAL OF MUCH COLDER AIR...HEAVY FREEZING SPRAY MAY
IMPACT PORTIONS OF THE LAKE ON THU...ESPECIALLY THE NCENTRAL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLA
SHORT TERM...JLA
LONG TERM...KC
AVIATION...JLA
MARINE...JLA/KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
311 AM CST SUN FEB 5 2012
.DISCUSSION...
THE FORECAST CONCERN IN THE NEAR TERM REMAINS THE STRATUS OVER THE
REGION ONCE AGAIN THIS MORNING. SOUTHEAST MOVEMENT OF CLOUD DECK
SHOULD ENVELOP ALL OF MINNESOTA PORTION OF THE REGION. HRRR TRENDS
INDICATE NORTHEAST WISCONSIN CLOUDS TO WORK SOUTHWEST INTO THAT
REGION DURING THE MORNING. VSBYS NOT ALL THAT BAD THIS AM...WITH
MOST AREAS ABOVE 2SM. DOES APPEAR MORE WEST/SOUTHWEST FLOW
DEVELOPING AHEAD OF NEXT COLD FRONT SHOULD BE ENOUGH TO MIX OUT
THE STRATUS OVER THE NORTHWEST PORTION OF THE AREA THIS AFTERNOON.
WILL MENTION PARTLY CLOUDY DEVELOPING IN THE SOUTHEAST...AS
CONFIDENCE NOT HIGH ON STRATUS TOTALLY CLEARING OUT. SHOULD SEE
TEMPERATURES WARM THROUGH THE 30S INTO THE 40S WHERE CLOUDS CLEAR
FASTEST TODAY.
COLD FRONT DROPS INTO NORTHERN MINNESOTA OVERNIGHT TONIGHT. WITH
SOUTHWEST FLOW DEVELOPING SHOULD SEE TEMPERATURES STAY UP A BIT
OVERNIGHT. COULD SEE A TOUCH OF FOG OVER WESTERN WI THIS
EVENING...BUT WILL LIKELY IMPROVE AFTER MIDNIGHT IF IT DOES
DEVELOP...AS FRONT/PRESSURE GRADIENT SAGS INTO THE AREA. TEMPERATURES
SHOULD START OUT RATHER WARM MONDAY AND SHOULD SEE SOME UPPER 40S
AGAIN IN THE FAR SOUTH BEFORE FROPA IN THE AFTERNOON. CLOUDS MAY
HOLD OFF UNTIL EVENING OVER MUCH OF THE AREA...BUT DO EXPECT THEM
AROUND MUCH OF MONDAY NIGHT. MAY EVEN SEE A FLURRY OR TWO.
FLOW PATTERN APPEARS TO BE IN TRANSITION AGAIN AS WESTERN BLOCK
REMAINS. GFS AND GEM TREND AM AMPLIFICATION OF THE EASTERN CONUS
TROUGH WITH THE GFS THE MOST AMPLIFIED/COLDEST. THE 00Z ECMWF
CONTINUES ITS TREND OF DIVING SOME TROUGH ENERGY SOUTH OVER THE
EASTERN CONUS THROUGH THE WEEK BUT THE WESTERN BLOCK IS ERODED
WEST LATE IN THE WEEK WITH A MORE ZONAL TYPE FLOW PATTERN
DEVELOPING INTO THE HE WEEKEND. EXTENDED DISCUSSION DID MENTION
THEY DID NOT LIKE THE ECMWF TREND...AND THEY HELD ONTO THE EASTERN
CONUS TROUGH A BIT LONGER. THIS DOES SPELL COLDER THAN NORMAL FOR
LATE IN THE WEEK. AT THE MOMENT...PERIOD IS DRY...BUT THERE MAY BE
A FEW SNOW SHOWERS/FLURRIES...MAINLY EAST...AS COLDEST AIR
ARRIVES THURSDAY INTO FRIDAY.
&&
.AVIATION.../06Z TAF ISSUANCE/
THE MAIN FORECAST CONCERNS AND CHALLENGES ARE THE STRATUS AND FOG
THAT WILL CONTINUE TO DEVELOP EAST OVER THE FORECAST AREA OVERNIGHT.
DURING THE EVENING...THE STRATUS HAD EXPANDED EAST AND SOUTH BACK
OVER THE TWIN CITIES...ALBERT LEA AND ONAMIA. VISIBILITIES HAVE
FARED IN THE MARGINAL VFR CATEGORY WHILE CEILING WERE IN THE
LIFR/IFR RANGE. VISIBILITIES HAD LOWERED BELOW A MILE OVER MUCH OF
WEST CENTRAL AND SOUTH CENTRAL MN. WEST TO NORTHWEST WINDS IN THE
LOWER ATMOSPHERE...WERE KEEPING THE SHALLOW MOIST LAYER FROM
BECOMING SATURATED BELOW THE INVERSION. MUCH OF THE MOISTURE WILL
PROBABLY SHAKE OUT AS FROST. EXPECT SOME AREAS OF FOG THROUGH MID
SUNDAY MORNING...THEN THE FOG/STRATUS SHOULD BEGIN TO ERODE AND LIFT
SHORTLY AFTERWARDS. WEATHER CONDITIONS BY NOON...SHOULD BE VFR
ACROSS MOST OF THE AREA. SURFACE HIGH PRESSURE RIDGE IS FORECAST TO
MOVE OVER WESTERN MN DURING THE AFTERNOON. MEANWHILE...A COLD FRONT
WILL SLIDE SOUTH INTO NORTHERN MINNESOTA BY MIDNIGHT TOMORROW
NIGHT.
MSP...IFR/LIFR FLYING CONDITIONS WILL PREVAIL THROUGH MID MORNING
SUNDAY. STRATUS LOW CLOUDS WILL CONTINUE TO PUSH EAST TO THE ST
CROIX RIVER VALLEY BY 300 AM. VISIBILITIES LOWER TO 2-3 MILES AFTER
MIDNIGHT...AND VISIBILITIES BRIEFLY LOWERING BELOW A MILE AT TIMES.
BETWEEN 900 AND 10 AM...THE FOG SHOULD HAVE BURN OFF OR ERODE. VFR
CONDITIONS PREVAILING DURING THE REST OF THE PERIOD.
.MON...VFR.
.TUE...MVFR CIGS WITH PASSAGE OF CLD FRNT.
.WED...VFR.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/JPR
AREA FORECAST DISCUSSION
NWS ST LOUIS MO
257 AM CST SUN FEB 5 2012
.DISCUSSION...
/255 AM CST SUN FEB 5 2012/
THE SHORT TERM FORECAST OVER THE NEXT 12 HOURS POSES THE BIGGEST
CHALLENGES OVER THE NEXT SEVERAL DAYS. THE FEATURE OF CONCERN IS
THE UPPER LOW FORECAST TO DROP SEWD THROUGH THE AREA TODAY AND THE
ASSOCIATED IMPACTS. PROFILER AND VWP DATA SHOW THAT THE UPPER LOW
HAS PASSED JUST SE OF KANSAS CITY. THE VAST MAJORITY OF PRECIPITATION
THUS FAR HAS ACTUALLY BEEN TO THE NORTH OF THE LOW CENTER...AND
HAS BEEN ROTATING SOUTHWESTWARD ABOUT THE CIRCULATION. NEAR AND
NORTH OF THE LOW ARE THE ONLY LOCATIONS THAT HAVE REPORTED ANY
SNOW THUS FAR AS WELL. CURRENTLY TO THE EAST OF THE LOW ACROSS
EASTERN MO...BANDS OF RAIN SHOWERS HAVE DEVELOPED WITHIN THE LAST
FEW HOURS WITHIN WHAT APPEARS TO BE A REGION OF MID LEVEL QG
FORCING. TEMPERATURES WITHIN THIS AREA RANGE FROM THE UPPER 30S TO
LOWER 40S. THE RUC APPEARS TO HAVE THE BEST HANDLE ON THE TRACK OF
THE UPPER LOW AT THIS TIME...TRACKING IT TO NEAR THE LAKE OF THE
OZARKS REGION BY 18Z. THEREAFTER THE MAJORITY OF THE MODELS WOULD
SUGGEST IT WILL CONTINUE TO TRACK SEWD AND INTO SE MO THIS
AFTERNOON AND THEN EXIT INTO THE WESTERN TN VALLEY TONIGHT. BASED
ON THIS LOW TRACK AND THE ASSOCIATED QG FORCING TO THE EAST...EXPECTING
CHANCE POPS/SCATTERED SHOWERS/DRIZZLE TO IMPACT THE AREA FROM
COU-STL-SLO SOUTHWARD. I AM NOT VERY EXCITED ABOUT THE PROSPECTS
OF ANY SNOW AND GIVEN ONLY SLIGHTLY COOLER TEMPERATURES EARLY THIS
MORNING THAN NOW...I WOULDN`T EXPECT ANY ACCUMULATION IF WE DID
SEE SOME. BY THIS AFTERNOON THE POP THREAT SHOULD BE CONFINED TO
FAR SE MO. STRATUS WILL SLOWLY CLEAR SOUTH THROUGH THE DAY AS
WELL.
WEAK HIGH PRESSURE WILL DOMINATE THE REGION TONIGHT WITH
SEASONABLY CHILLY TEMPERATURES. WESTERLY LOW LEVEL FLOW AND WARM
ADVECTION THEN GETS GOING ON MONDAY AND TEMPERATURES WILL ONCE
AGAIN BE ABOVE AVERAGE. THE NEXT SHOT OF COLD AIR LOOKS ON TRACK
FOR TUESDAY AS A NORTHERN STREAM SHORT WAVE TROF DIGS SOUTHEAST
INTO THE UPPER MIDWEST AND INTERACTS WITH THE REMNANT GREAT BASIN
UPPER LOW. WE CURRENTLY HAVE POPS JUST BELOW THRESHOLDS THAT ARE
MENTIONED IN THE FORECAST FOR THIS SYSTEM. THERE IS AND HAS BEEN
QUITE A BIT OF VARIABILITY WITH THE PRECIPITATION CHANCES...AND
CONFIDENCE IS LOW AT THIS TIME. ANYWAY THIS SHOT OF COLD AIR WILL BE A
GLANCING SHORT-LIVED BLOW BRINGING TEMPERATURES BACK DOWN TO
SEASONABLE NORMS TUESDAY NIGHT-WED NIGHT.
THE LONGER RANGE GUIDANCE...WHILE SHOWING SOME DETAIL DIFFERENCES
...IS TRENDING TOWARDS TEMPERATURES MORE WINTER-LIKE BY THE END
OF THE UPCOMING WEEK. THE GENERAL IDEA AT THIS JUNCTURE IS A DEEP
VORTEX WILL BECOME ESTABLISHED NEAR HUDSON BAY WITH A DEEP FULL
LATITUDE TROF EXTENDING TO THE SOUTH INTO THE EASTERN U.S.. THE
ORIENTATION OF THIS TROF AND INTENSITY/LONGEVITY OF THE COLD AIR
ARE WHERE THE MODELS DIFFER WITH THE GFS SHOWING POTENTIAL FOR
SOME OF THE COLDEST AIR THIS SEASON.
GLASS
&&
.AVIATION...
/1125 PM CST SAT FEB 4 2012/
MAIN FOCUS WILL BE CIGS/VSBYS. REMOVED MENTION OF SN AT COU AS ANY
PRECIP SHUD REMAIN LIQUID WITH SN REMAINING FURTHER W. BELIEVE DZ
WILL PERSIST THRU MUCH OF THE NIGHT. CONDITIONS AT UIN SHUD BEGIN
TO IMPROVE AS DRIER AIR ADVECTS INTO THE AREA. WITH DZ COMING TO
AN END AT SUS/CPS...VSBYS SHUD IMPROVE OVERNIGHT...THO PATCHES OF
DZ MAY DEVELOP AGAIN LATER TONIGHT.
SPECIFICS FOR KSTL...VSBYS SHUD IMPROVE AS DZ HAS COME TO AN
END...THO CAN NOT RULE OUT REDEVELOPMENT BEFORE SUNRISE. CIGS SHUD
IMPROVE MID TO LATE SUNDAY MORNING. WINDS EXPECTED TO REMAIN NELY
TO NLY THRU PERIOD AND DIMINISH SUNDAY AFTERNOON AS THE SFC RIDGE
BUILDS IN. CONDITIONS SHUD BE FAVORABLE FOR FG DEVELOPMENT SUN
NIGHT. HOWEVER...CONFIDENCE THIS FAR OUT IS TOO LOW TO MENTION IN
TAF ATTM.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1137 PM CST SAT FEB 4 2012
.UPDATE...
/955 PM CST SAT FEB 4 2012/
OUTSIDE OF AREAS OF DRIZZLE FROM CENTRAL INTO EAST CENTRAL
MO...PRECIP DEVELOPMENT AHEAD OF UPPER LOW HAD BEEN ALMOST NON-
EXISTANT IN OUR CWA. IN SPITE OF THIS...AM RELUCTANT TO TOTALLY
GIVE UP ON PRECIP TONIGHT. FOR THE UPDATE HAVE USED THE CURRENT
PRECIP OVER NW MO AND ITS RELATIONSHIP TO THE 7H LOW. FROM RUC AND
NAM...LOW IS FORECAST TO BE NEAR STL BY 12Z SUN...SO HAVE LAYED
OUT A NARROW BAND OF LIKELY POPS ALONG THE MO PORTION OF THE I-70
CORRIDOR FOR THE PREDAWN HOURS. AS FAR AS PTYPE IS
CONCERNED...HAVE PRETTY MUCH STAYED WITH THE TRENDS IN GOING
FORECAST. THIS MAY BE A BIT TOO FAST WITH THE RAIN TO SNOW
TRANSITION...BUT WITH THESE CLOSED UPPER SYSTEMS HAVE SEEN ENOUGH
INSTANCES WHERE FREEZING LEVELS RAPIDLY DROP THAT I DIDN`T WANT TO
GET TOO CUTE WITH THE TIMING. WOULD STILL THINK ANY ACCUMULATIONS
WOULD BE SPOTTY...AND UNDER AN INCH. UPDATE REFLECTING ABOVE
TRENDS HAS BEEN SENT.
TRUETT
&&
.SYNOPSIS...
/345 PM CST SAT FEB 4 2012/
WATER VAPOR LOOP SHOWS AN W-E ELONGATED MID LEVEL LO CENTER OVER THE
INTERFACE BETWEEN KS-NE-MO...SLOWLY OOZING E. A SPLIT FLOW PATTERN
OTHERWISE DOMINATES WRN NOAM WITH A REX BLOCK IN PLACE AND A MORE
UNIFIED FLOW OVER ERN NOAM. RADAR MOSAIC SHOWS DEFORMATION ZONE
PCPN ON THE NRN FLANK OF THE MID LEVEL FLOW AND EXTENDING EWD THRU
SRN-CNTRL IA AND NRN IL. FROM THE LO CENTER THRU CNTRL IA...THE AIR
IS COLD ENOUGH FOR THIS PCPN TO FALL AS SNOW...OTHERWISE FOR AREAS
FURTHER TO THE E...IT IS RAIN. 21Z MSAS DATA INDICATES TWO LO PRES
CENTERS...THE TRIPLE POINT OVER WRN KY AND AN OLD OCCLUDED CENTER IN
E CNTRL MO. CLOUDY SKIES ABOUND...EXCEPT IN SERN MO WHERE SUN HAS
BROKEN THRU...AND THIS HAS ALLOWED TEMPS TO WARM INTO THE MID-UPR
50S THERE. TEMPS HAVE OTHERWISE REMAINED IN THE 40S ELSEWHERE UNDER
THE THICK CLOUD CANOPY.
TES
&&
.DISCUSSION...
/345 PM CST SAT FEB 4 2012/
UPPER LOW WITH WEAK SFC LOW WILL DROP SEWD TGT AS AN UPPER LEVEL
RIDGE AND SFC RIDGE OVER THE NRN PLAINS SHIFTS SEWD. AREAS OF
DRIZZLE WILL CONTINUE THIS EVNG WHILE DEFORMATION ZONE
PRECIPITATION ACROSS SERN NEBRASKA AND SRN IA DROP SEWD THROUGH
NERN AND CNTRL MO AS WELL AS W CNTRL IL TGT. THE MODELS ARE FAIRLY
CONSISTENT WITH THE PLACEMENT OF THE PRECIPITATION FORECAST TGT AS
WELL AS THE WEAKENING TREND OR LESSENING OF THE QPF THROUGH TGT
INTO SUN MRNG. LOOKING AT MODEL PARTIAL THICKNESS FORECASTS AND
FORECAST SOUNDINGS THE P-TYPE SHOULD CHANGE FROM LIGHT RAIN TO
LIGHT SNOW IN COU AND UIN AROUND 06Z SUN OR SHORTLY AFTER...THEN
TRANSITION TO LIGHT SNOW JUST NW OF THE STL METRO AREA BY 12Z SUN
ALTHOUGH BY THIS TIME LITTLE IF ANY QPF WIL BE LEFT. WHILE MOST
AREAS N AND W OF THE STL METRO AREA WILL LIKELY ONLY RECEIVE A
LIGHT DUSTING OF SNOW... COULD NOT RULE OUT ONE HALF INCH TO NEAR
ONE INCH OF SNOW BETWEEN EDINA AND COLUMBIA MO TGT.
GKS
HOW WELL THE LO CENTER GETS PICKED UP BY A NRN STREAM SHORTWAVE
DROPPING THRU THE GREAT LAKES ON SUNDAY WILL PLAY A HUGE ROLE IN HOW
FAST THE LO CENTER MOVES THRU THE FA...WHICH WILL AFFECT HOW FAST
THE PCPN ENDS AND WHEN WE CLEAR OUT. MOST MODELS SAVE THE GFS ARE
BANKING ON THE NRN STREAM WAVE NOT PICKING UP THE OLD CNTRL CONUS LO
TOO WELL AND ARE THUS KEEPING PCPN AND CLOUDS AROUND FOR LONGER.
PCPN CURRENTLY TO OUR N IS BEING DRIVEN BY A MATURE WINTER STORM
WITH MAINLY MID LEVEL BROADSCALE FORCING AND FRONTOGENESIS...BUT
WITH SOME UPR LEVEL JET DYNAMICS TOO...TO GIVE US OUR DEFORMATION
ZONE PCPN. FRONTOGENESIS AND UPR JET DYNAMICS WILL BE THE FIRST TO
FADE LEAVING BEHIND A DILUTED STRENGTH AREA OF BROADSCALE LIFT THAT
WILL SURVIVE TO SUNDAY MORNING WHILE CONTINUING TO SLOWLY SLIDE
SEWD. WHILE MODEL SOUNDINGS SUGGEST WHAT SURVIVES WILL BE MAINLY
RAIN...EXPANDED THE AREA OF RAIN/SNOW MIX GIVEN THAT WET BULB ZERO
VALUES ARE FORECAST TO DIP JUST BELOW 1KFT AGL LEAVING LITTLE MARGIN
FOR ERROR. A FEW SPOTS MAY SEE A LIGHT DUSTING AS A RESULT...BUT
WITH SFC TEMPS ABOVE 32F IN MOST LOCATIONS...IT WILL BE DIFFICULT.
ANY PCPN THAT LINGERS MUCH PAST MID MORNING WILL BE RAIN AS TEMPS
BEGIN TO EDGE HIGHER. PREFERRED A MOS BLEND IN THE N WHERE THEY
WILL SEE SUN...BUT LEANED WITH THE COLDER MOS ELSEWHERE.
EVENING CLEARING OR CLEAR SKIES EXPECTED FOR SUNDAY NIGHT WITH HI
PRES SETTLING IN...SO AT LEAST MATCHED THE COLDEST MOS FOR MIN
TEMPS. QUIET WX THEN THRU TUESDAY MORNING WITH HI PRES IN CONTROL
AT THE SFC...BUT THIS WILL GIVE WAY TO A CDFNT LATER ON TUESDAY
WHERE INTRODUCED SOME CHCS FOR POST-FRONTAL PCPN...AS THE FRONT
ITSELF NOT STRONG ENOUGH TO KICK OFF PCPN BUT RATHER THIS WILL BE
FROM AN APPROACHING NEW CUTOFF LO FROM THE CNTRL ROCKIES. DEPENDING
ON HOW FAST THE COLD AIR RUSHES IN BEHIND THE FRONT AND HOW FAST THE
EWD TRANSLATION WILL BE WITH THAT CUTOFF LO...SOME OF THE PCPN COULD
BE SNOW IN THE FAR NRN FA...BUT MOST AREAS SHOULD SEE RAIN TUES AFTN
IF THEY GET ANYTHING AT ALL. THIS SYSTEM IS EXPECTED TO WEAKEN AS
IT MOVES E...VERY MUCH LIKE THE ONE WE ARE DEALING WITH NOW...BUT
TIMING ISSUES CONTINUE. EDGED POPS HIGHER FOR MID WEEK WITH THIS
SYSTEM BUT RELUCTANT TO DO MUCH MORE THAN THAT UNTIL WE GET BETTER
CONSENSUS ON TIMING AND TRACK. MORE POTENT ECMWF SUGGESTS POTENTIAL
FOR SOME ACCUMULATING SNOW...BUT IS AN OUTLIER AT THIS TIME.
MEDIUM RANGE HAS COME INTO BETTER AGREEMENT BETWEEN MODELS WITH A
PATTERN CHANGE IN THE AIR...AS A HI-AMPLITUDE BLOCKING RIDGE SETS UP
OVER WRN NOAM ALLOWING A DEEP TROF TO DEVELOP IN THE E. SOME
DISAGREEMENT ON HOW FAR S THIS TROF WILL PLUNGE...BUT THERE IS
AGREEMENT IN THAT IT WILL LAST THRU LATE WEEK AND INTO NEXT
WEEKEND. SOMETHING WE HAVE RARELY SEEN THIS WINTER. TEMPS
GENERALLY AVERAGE TO BELOW AVERAGE THIS PERIOD...WAITING ON MORE
AGRESSIVELY GOING LOWER...WITH FEW PCPN CHCS OUTSIDE OF THE MID WEEK
SYSTEM.
TES
&&
.AVIATION...
/1125 PM CST SAT FEB 4 2012/
MAIN FOCUS WILL BE CIGS/VSBYS. REMOVED MENTION OF SN AT COU AS ANY
PRECIP SHUD REMAIN LIQUID WITH SN REMAINING FURTHER W. BELIEVE DZ
WILL PERSIST THRU MUCH OF THE NIGHT. CONDITIONS AT UIN SHUD BEGIN
TO IMPROVE AS DRIER AIR ADVECTS INTO THE AREA. WITH DZ COMING TO
AN END AT SUS/CPS...VSBYS SHUD IMPROVE OVERNIGHT...THO PATCHES OF
DZ MAY DEVELOP AGAIN LATER TONIGHT.
SPECIFICS FOR KSTL...VSBYS SHUD IMPROVE AS DZ HAS COME TO AN
END...THO CAN NOT RULE OUT REDEVELOPMENT BEFORE SUNRISE. CIGS SHUD
IMPROVE MID TO LATE SUNDAY MORNING. WINDS EXPECTED TO REMAIN NELY
TO NLY THRU PERIOD AND DIMINISH SUNDAY AFTERNOON AS THE SFC RIDGE
BUILDS IN. CONDITIONS SHUD BE FAVORABLE FOR FG DEVELOPMENT SUN
NIGHT. HOWEVER...CONFIDENCE THIS FAR OUT IS TOO LOW TO MENTION IN
TAF ATTM.
TILLY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
235 AM CST SUN FEB 5 2012
.SHORT TERM...TODAY THROUGH TUESDAY NIGHT. 11-3.9 MICRON
SATELLITE IMAGERY EARLY THIS MORNING SHOWED A LARGE AREA OF
STRATUS DROPPING SOUTH FROM EASTERN SOUTH DAKOTA AND MINNESOTA
INTO EASTERN NEBRASKA. THE MODELS OVERALL HAVE NOT DONE A GOOD JOB
IN CAPTURING THIS AREA...THOUGH THE HRRR DOES SEEM TO HAVE AN IDEA
OF ITS PRESENCE. FOLLOWING THE HRRR WOULD SUGGEST THE WESTERN EDGE
OF THE STRATUS COULD MAKE A RUN FOR FAR EASTERN PORTIONS OF THE
FORECAST AREA. WILL INCREASE CLOUDS ACCORDINGLY...BUT IT WILL BE A
SHARPLY DEFINED LINE BETWEEN CLOUDS VS. SUN.
THE NEXT ISSUE WILL BE TEMPERATURES...AND THE MAIN MESSAGE IN THE
FORECAST THE NEXT COUPLE OF DAYS WILL BE TO CUT GUIDANCE
VALUES...ESPECIALLY IN THE HEART OF THE DEEPER SNOWPACK. AM NOT
OVERLY CONFIDENT ABOUT HOW FAR BELOW GUIDANCE TO GO...AND WILL STAY
FAIRLY CLOSE TO THE GOING FORECAST WHICH IS ABOUT 5 TO 10 DEGREES
BELOW BOTH MET AND MAV HIGH TEMPERATURE FORECASTS.
DEBATED ADDING AT LEAST SOME PATCHY FOG TO THE FORECAST TONIGHT WITH
THE 05.00Z NAM SHOWING REDUCED VISIBILITIES OVERNIGHT INTO MONDAY
MORNING. THE MAIN THING THAT KEPT US FROM JUMPING ON IT AT THIS
POINT IS THAT BOUNDARY LAYER RELATIVE HUMIDITY VALUES ARE NOT VERY
HIGH OVERNIGHT...AND PROXIMITY SOUNDINGS ONLY SHOW A VERY SHALLOW
AREA OF NEAR SATURATION. THINK WE MAY SEE SOME VERY SHALLOW GROUND
FOG...BUT WILL LET THE DAY SHIFT TAKE ANOTHER LOOK AT IT BEFORE
ADDING.
THE NEXT CHANCE FOR SNOW COULD ARRIVE MONDAY NIGHT INTO TUESDAY DUE
TO THE ARRIVAL OF THE NEXT MID LEVEL WAVE. CURRENTLY THE SYSTEM IS
SPINNING ACROSS THE INTERMOUNTAIN WEST...AND THE MODELS HAVE COME
INTO GENERAL AGREEMENT THAT IT WILL OPEN UP AND SHIFT ACROSS THE
CENTRAL AND SOUTHERN PLAINS MONDAY INTO TUESDAY. THE FINER DETAILS
REMAIN A BIT DIFFERENT...BUT THE OVERALL MESSAGE FROM THE
DETERMINISTIC MODEL RUNS ALONG WITH THE SREF IS THAT CHANCES OF SNOW
WILL INCREASE MONDAY EVENING IN WESTERN PARTS OF THE FORECAST
AREA...WITH THE CHANCES SPREADING SOUTH AND EAST OVERNIGHT MONDAY
INTO TUESDAY. DISCREPANCIES REMAIN IN THE MODEL GENERATED QPF
FIELDS...BUT BASED ON THE SPEED AND STRENGTH OF THIS SYSTEM IT
APPEARS IT COULD TRY TO GENERATE AN INCH OR SO OF SNOW...PRIMARILY
ACROSS PARTS OF NORTH CENTRAL KANSAS INTO FAR SOUTHERN NEBRASKA.
.LONG TERM...WEDNESDAY THROUGH SATURDAY. CONFIDENCE IS REASONABLY
HIGH FOR DRY WEATHER THROUGH THIS 4-DAY PERIOD...ALTHOUGH
CONFIDENCE IN TEMPERATURE TRENDS IS A BIT SHAKY OWING NOT ONLY TO
MODEL DIFFERENCES...BUT ALSO TO UNCERTAINTY IN HOW MUCH IMPACT THE
FRESH SNOW PACK WILL HAVE ON HIGHS. THAT BEING SAID...IT CERTAINLY
LOOKS LIKE AT LEAST SLIGHTLY BELOW-NORMAL TEMPS WILL PERSIST
THROUGH THE PERIOD...AND CURRENT FORECAST MAY NOT BE COLD ENOUGH
AT TIMES...ESPECIALLY OVER THE DEEPER SNOW NEAR/NORTH OF HIGHWAY
6.
STARTING THINGS OUT WEDNESDAY/WEDNESDAY NIGHT...00Z GFS AND ECMWF
RUNS ARE IN REASONABLE AGREEMENT DEPICTING A GENERAL NORTHWEST
FLOW ALOFT OVER THE CENTRAL PLAINS...WITH THE PRIMARY SYNOPTIC LOW
PRESSURE SYSTEMS CONSISTING OF A HUDSON BAY VORTEX WELL TO THE
NORTHEAST...AND A SLOW-MOVING CLOSED LOW OFF BAJA WELL TO THE
SOUTHWEST. MEANWHILE...A LOWER AMPLITUDE MID LEVEL WAVE WILL BE
MOVING AWAY FROM IA EASTWARD. AT THE SURFACE...THERE IS GENERAL
AGREEMENT IN SURFACE HIGH PRESSURE SLIDING EAST DURING THE
DAY...INDUCING SOUTHERLY BREEZES...WHICH THEN TURN MORE WESTERLY
OR POSSIBLY NORTHERLY OVERNIGHT AS THE NEXT COLD FRONT MOVES
IN...BUT THE GFS SOLUTION IS DEFINITELY MUCH MORE AGGRESSIVE WITH
THIS FRONTAL INVASION THAN THE ECMWF. FOR HIGH TEMPS WED...CHANGED
VERY LITTLE FROM PREVIOUS FORECAST...REMAINING A SOLID 3-4 DEGREES
BELOW 00Z MEX GUIDANCE MAINLY TO ACCOUNT FOR SNOW PACK. THIS KEEPS
MOST NEB ZONES ONLY IN THE UPPER 20S...WITH LOW-MID 30S MORE
PREVALENT IN KS ZONES.
THURSDAY/THURSDAY NIGHT...ECMWF/GFS SOLUTIONS AGREE THAT A HIGHLY
AMPLIFIED MID-UPPER RIDGE WILL BUILD OVER THE WESTERN CONUS...BUT
EAST OF THIS FEATURE...THE GFS IS MUCH MORE AGGRESSIVE MOVING A
SHORTWAVE SOUTHWARD THROUGH THE PLAINS...ROTATING AROUND THE MAIN
HUDSON BAY REGION VORTEX. THIS IN TURN MAKES THE GFS MUCH MORE
AGGRESSIVE WITH LOW LEVEL COLD AIR ADVECTION INTO THE CWA. FOR
MOST AREAS KEPT HIGH TEMPS SIMILAR TO BOTH PREVIOUS FORECAST AND
00Z MEX GUIDANCE...WITH LOW 30S OVER DEEPER SNOW AND MID 30S
SOUTH.
FRIDAY/FRIDAY NIGHT...DIFFERENCES WITH SYNOPTIC FEATURES ALOFT
BETWEEN 00Z ECMWF/GFS SOLUTIONS CONTINUE TO MAGNIFY...WITH THE
ECMWF TRYING TO BUILD A SHORTWAVE RIDGE INTO THE CENTRAL PLAINS
MAINLY FRIDAY NIGHT...WHILE THE GFS DROPS AN AMPLIFYING SHORTWAVE
SOUTH THROUGH THE UPPER MS VALLEY/MIDWEST. THIS RESULTS IN A
DRAMATIC DIFFERENCE IN 850MB TEMPS ACROSS THE CWA...AND ALSO WIND
DIRECTION...ESPECIALLY FOR FRIDAY NIGHT WITH THE ECWMF SUGGESTING
OVERNIGHT WARM AIR ADVECTION. THE 00Z GFS ENSEMBLE MEAN 500MB
HEIGHT IS A MIDDLE GROUND BETWEEN THE DETERMINISTIC ECMWF/GFS
SOLUTIONS...AND THUS FOR HIGHS FRIDAY STUCK CLOSE TO MODEL
CONSENSUS WITH MID-UPPER 20S MOST NEB ZONES...AND MID 30S FARTHER
SOUTH. THIS UNDERCUTS 00Z MEX HIGHS BY 2-3 DEGREES MOST AREAS.
FINALLY FOR SATURDAY...CONFIDENCE REALLY GOES IN THE TANK ON THE
SYNOPTIC SCALE PATTERN...WITH THE GFS SHOWING AN EXPANSIVE
COLD SURFACE RIDGE OVER THE PLAINS...WHILE THE ECMWF HAS
IMPRESSIVE WARM ADVECTION AND SOUTHERLY BREEZES AHEAD OF A
SHORTWAVE CROSSING THE CENTRAL ROCKIES. THIS IMPLIES HIGH
TEMPERATURES COULD EASILY RANGE ANYWHERE FROM 20S TO AT LEAST 40S
ACROSS PARTS OF THE CWA...AND FOR NOW WILL PLAY CONSENSUS MIDDLE
GROUND WITH LOW 30S NORTHEAST TO LOW 40S SOUTHWEST. LOTS TO IRON
OUT AT THIS RANGE.
DESPITE THE UPCOMING STRETCH OF BELOW NORMAL TEMPERATURES...EXTENDED
MODELS SHOW NO SIGN OF A LEGITIMATE ARCTIC INVASION. ON ONE FINAL
NOTE...NOW THAT PLENTY OF SNOW IS ON THE GROUND AND LOOKS TO BE
SLOW TO FULLY MELT...THERE COULD EASILY BE POTENTIAL FOR FOG
AND/OR LOW STRATUS DURING THE NEXT WEEK...WITH THE DETAILS JUST
TOO MURKY TO RESOLVE AT THIS TIME.
&&
.PREV DISCUSSION... /ISSUED 1124 PM CST SAT FEB 4 2012/
AVIATION...06Z KGRI TAF. VFR CEILING/VISIBILITY ARE CURRENTLY
ADVERTISED THROUGHOUT THE PERIOD...WITH LIGHT WEST-NORTHWEST
BREEZES ONLY AVERAGING AROUND 7KT OR SO. THAT BEING SAID...NOW
THAT EXTENSIVE SNOW COVER IS ON THE GROUND...THE NEXT SEVERAL DAYS
AND ESPECIALLY NIGHTS WILL HAVE TO BE CLOSELY MONITORED FOR THE
POTENTIAL FOR FOG AND/OR LOW STRATUS TO MATERIALIZE. AT THIS
TIME...ONE OF THESE FAIRLY EXTENSIVE IFR/LIFR STRATUS DECKS IS
LURKING ROUGHLY 140 MILES NORTH-NORTHEAST OF THE TERMINAL...AND IS
SHOWING SOME SIGNS OF SAGGING SOUTH TOWARD THE AREA OVER THE NEXT
12-18 HOURS WITH THE LOW LEVEL STEERING FLOW. AT THIS
TIME...TRADITIONAL NUMERICAL GUIDANCE AND MOST SHORT TERM MODEL
DATA KEEP THESE LOW CLOUDS AT LEAST SLIGHTLY EAST OF KGRI...BUT
THIS WILL NEED CLOSELY MONITORED. EVEN IF LOW STRATUS STAYS
AWAY...THE BEGINNING STAGES OF SNOW MELT AND CONTINUED LIGHT WINDS
COULD PROMOTE AT LEAST PATCHY FOG DEVELOPMENT MAINLY FOR SUNDAY
EVENING/OVERNIGHT. ALL THESE CAVEATS BEING SAID...GIVEN LACK OF
SUPPORT FROM CURRENT MODEL GUIDANCE...WILL MAINTAIN VFR CONDITIONS
FOR NOW BUT AT LEAST HINT AT POSSIBLE ISSUES BY INSERTING A
SCATTERED LOW STRATUS GROUP FOR MUCH OF THE PERIOD...AND A LIGHT
VFR VISIBILITY RESTRICTION SUNDAY EVENING. BOTTOM LINE...THIS
FORECAST MAY NOT BE QUITE AS STRAIGHTFORWARD AS CURRENT GUIDANCE
WOULD SUGGEST.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...KING
LONG TERM/AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BISMARCK ND
329 AM CST SUN FEB 5 2012
.SHORT TERM...TODAY THROUGH MONDAY...
THE CHALLENGE FOR THE MORNING IS ONCE AGAIN PREDICTING THE
DISSIPATION OF FOG AND LOW STRATUS CONFINED MOSTLY TO AREAS ALONG
AND NORTH AND EAST OF THE MISSOURI RIVER. THE DETERMINISTIC
MODELS ARE HAVING A VERY DIFFICULT TIMING RESOLVING THE
STRATUS...WITH THE 06 UTC HRRR THE ONLY MODEL WITH A HANDLE ON THE
EVENT...SUGGESTING DISSIPATION OF THE FOG AND STRATUS BY EARLY
AFTERNOON AT THE LATEST AS MIXING INCREASING AHEAD OF A SURFACE
TROUGH. HAVE TRENDED SLIGHTLY FASTER THAN THE
HRRR...HOWEVER...MUCH UNCERTAINTY AS TO WHEN THE STRATUS WILL
COMPLETELY DISSIPATE DOES REMAIN. HAVE REMOVED MORTON AND SIOUX
COUNTIES FROM THE DENSE FOG ADVISORY...AND WILL LEAVE THE
REMAINING COUNTIES IN PLACE THROUGH 15 UTC. TWO OTHER PATCHES OF
DENSE FOG ARE BEING OBSERVED AS OF 09 UTC...INCLUDING THE
WILLISTON THROUGH TIOGA AREAS AND RUGBY THROUGH BOTTINEAU. DUE TO
THE VERY LOCALIZED NATURE OF THESE AREAS...WILL COVER WITH AN SPS.
A VERY MILD EARLY FEBRUARY DAY IS FORECAST ACROSS WESTERN AND
CENTRAL NORTH DAKOTA TODAY DUE IN LARGE PART TO THE ABSENCE OF SNOW
COVER ACROSS THE AREA. THE ABUNDANCE OF BROWN GROUND WILL YIELD
GREATER MIXING HEIGHTS ENABLING THE RELATIVELY MILD TEMPERATURES IN
THE 850-800 MB LAYER OF +4 TO +6 C TO BE MIXED TO THE
SURFACE...RESULTING IN WIDESPREAD 50S FOR HIGH TEMPERATURES FOR MOST
AREAS...ESPECIALLY ALONG AND SOUTH OF THE MISSOURI RIVER...WITH
UPPER 40S FOR HIGHS FOR THE JAMES RIVER VALLEY...TURTLE MOUNTAINS
AND LOCATIONS ALONG THE INTERNATIONAL BORDER. TRENDED WELL ABOVE
THE DETERMINISTIC AND STATISTICAL CONSENSUS AND OPTED FOR THE SUPERIOR
VERIFICATION OF BIAS CORRECTED GUIDANCE GIVEN THE BROWN WINTER WE
ARE HAVING. SHOWN BELOW ARE THE FORECAST HIGHS AND RECORD HIGHS
FOR TODAY FOR THE MAJOR OBSERVING LOCATIONS. SEE THE FIRE WEATHER
DISCUSSION BELOW REGARDING FIRE DANGER FOR TODAY.
LOCATION........FORECAST...........RECORD
BISMARCK..........53...............56 1991
JAMESTOWN.........49...............58 1991
MINOT.............54...............58 1963
WILLISTON.........51...............55 1963
DICKINSON.........54...............58 1963
A SURFACE COLD FRONT IS FORECAST TO CROSS THE INTERNATIONAL BORDER
AROUND 00 UTC THIS EVENING AND PROPAGATE SOUTH THROUGH THE
NIGHT...ENTERING SOUTH DAKOTA BETWEEN 08 AND 10 UTC. GIVEN POST
FRONTAL MIXING AND WARM TEMPERATURES TO BEGIN THE OVERNIGHT...LOW
TEMPERATURES SUNDAY NIGHT SHOULD ONLY FALL INTO THE LOW 20S FOR MOST
LOCATIONS...WITH TEENS ALONG THE INTERNATIONAL BORDER. A BREEZY
MONDAY IS EXPECTED IN THE WAKE OF THE COLD FRONT AS 1045 MB SURFACE
HIGH BEGINS TO BUILD INTO THE STATE. AIDED BY AN AN ISALLOBARIC
COMPONENT FROM PRESSURE RISES AND LOW LEVEL COLD AIR ADVECTION
PROMOTING MIXING TO AROUND 825 MB...NORTHERLY WIND GUSTS TO 25 KTS
ARE EXPECTED FOR MOST AREAS WITH FLURRIES ASSOCIATED WITH STRATUS
APPROXIMATELY ALONG AND NORTH OF A LINE FROM CROSBY THROUGH
WASHBURN THROUGH EDGELEY. DESPITE THE COLD FRONTAL
PASSAGE...TEMPERATURES ON MONDAY WILL STILL BE ABOVE NORMAL THANKS
TO NO SNOWPACK WITH HIGHS FROM THE LOW TO MID 20S NORTH TO THE
LOWER 30S SOUTH.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
MODELS IN FAIR AGREEMENT WITH FEATURES IN LONG TERM. USED THE BLEND
WITH FEW CHANGES. LARGE MID AND UPPER LEVEL RIDGE LIES ALONG SPINE
OF THE ROCKIES WITH FAIRLY STRONG HIGH PRESSURE DROPPING SOUTH IN
LEE OF CANADIAN ROCKIES. 1044 HIGH WOULD INDICATE A VERY CHILLY
MIDDLE OF THE WEEK...HOWEVER WITH NO SIGNIFICANT SNOW COVER UPSTREAM
FROM THE THE CENTRAL ALBERTA AND SASKATCHEWAN BORDER...SOUTH THROUGH
THE NORTHERN PLAINS...TEMPERATURES WILL BE NORMAL OR SEVERAL DEGREES
ABOVE NORMAL.
ONLY ONE CHANCE OF ACCUMULATING PRECIPITATION WHICH WILL COME
WEDNESDAY NIGHT AS A REINFORCING SHOT OF MODIFIED ARCTIC AIR MOVES
SOUTH BEHIND A COLD FRONT. THE SYSTEM LOOKS QUITE DRY AND THE
HIGHEST POPS...SLIGHT CHANCE...ARE IN THAT PERIOD. WHILE AIR WILL BE
COLDER...THICKNESS AND 85H TEMPERATURES INDICATE THAT THE COLDEST
AIR WILL PASS JUST TO THE EAST OF THE FORECAST AREA BORDER.
&&
.AVIATION...
BAND OF STRATUS EXTENDS ABOUT 50 MILES EITHER SIDE OF MISSOURI
VALLEY FROM THE SOUTH DAKOTA BORDER NORTH TO NEAR LAKE
SAKAKAWEA...THEN NORTHEAST TO WILLISTON. SEVERAL OTHER MUCH SMALLER
BANDS LINGERED OVER EASTERN PORTIONS OF THE FORECAST AREA...KJMS AND
EAST AND KRUG AND EAST. THE AREAS SHOWED LITTLE MOVEMENT...BUT WERE
SLOWLY SHRINKING IN AREAL COVERAGE. HOWEVER THE MISSOURI VALLEY
ESPECIALLY FROM KBIS TO KISN WILL LINGER IN LIFR CONDITIONS FOR
SEVERAL MORE HOURS BEFORE A TRANSITION OF VFR BY THE AFTERNOON ALL
AERODROME SITES.
&&
.FIRE WEATHER...
SUNDAY LOOKS TO BE VERY MILD ACROSS WESTERN AND CENTRAL NORTH
DAKOTA WITH HIGHS IN 50S. WITH PLENTIFUL DRY VEGETATION IN
PLACE...AND AFTERNOON RELATIVE HUMIDITY VALUES EXPECTED TO FALL
INTO THE 25 TO 35 PERCENT RANGE ESPECIALLY ALONG AND SOUTH OF THE
MISSOURI RIVER...THE ONE THING PREVENTING FIRE WEATHER CONCERNS
ARE WIND SPEEDS ONLY ON THE ORDER OF 10 TO 15 MPH.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR NDZ035>037-
046-047-050.
&&
$$
SHORT TERM/FIRE...PJA
LONG TERM/AVIATION....HW
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
245 AM EST SUN FEB 5 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. COLD FRONT PASSES TUESDAY NIGHT
FOLLOWED BY A WEAK WAVE MIDWEEK. ANOTHER COLD FRONT CROSSES FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CONSIDERABLE DIFFERENCES BETWEEN THE NAM AND GFS WITH THE HANDLING
OF THE LOW LEVEL MOISTURE TODAY. RUC SUPPORTS THE FASTER CLEARING
FOUND IN THE GFS. THEREFORE WILL LEAN MORE TOWARD THE FASTER
SOLUTION. WITH CALM WINDS TONIGHT AND DECENT RADIATION
CONDITIONS...WILL GO TOWARD THE LOWER END OF THE MOS GUIDANCE. WILL
ALSO INCLUDE VALLEY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
MDLS ARE STARTING TO CONVERGE ON HANDLING OF UPR LOW POISED TO MOVE
THRU ON MON. NAM/SREF CONT TO OPEN THIS UP INTO A WAVE ON
APPROACH...WITH REMAINDER OF GLOBAL MDLS KEEPING A STRONGER INTACT
CLOSED LOW AT H5. WILL FOLLOW HPC PREFERENCE FOR A ECWMF/GFS
BLEND...NOTING NAM TO BE AN OUTLIER ATTM. GIVEN THAT...WILL INCREASE
CLDS ACROSS S BY 18Z...WITH MOISTENING OF THE COLUMN THRU H7. WEAK
LIFT IN THIS LYR AIDED BY UPR LOW SHOULD ALLOW LIGHT PRECIPITATION
TO BREAK OUT ACROSS SW VA...SOUTHERN COAL FIELDS AND SOUTHERN AND
CENTRAL WV MTNS BY AFTN. GLOBAL MDLS DO INDICATE QPF WITH
THIS...ALBEIT VERY LIGHT. THEREFORE...INTRODUCED CHC POPS ACROSS
AFOREMENTIONED AREAS...MAINLY FOR AFTN AND EARLY EVE. TEMP PROFILES
SUPPORT MAINLY LIQUID...PERHAPS ENDING AS A FEW WET FLAKES ACROSS
THE MTNS EARLY EVE. WILL SEE A SHARP LINE BETWEEN SUN AND CLDS.
THINK AREAS NORTH OF I64 CORRIDOR WILL SEE MAINLY SUNSHINE.
LOOKING AT QUIET WX FOR TUE UNDER SFC HIGH. A S/W TROF MAY BRING A
FEW SHRA/SHSN TO THE AREA WED. IF NOTHING ELSE...WILL INCREASE THE
CLDS.
GUIDANCE VERY SIMILAR TO INHERITED NUMBERS...SO LITTLE CHANGE
NECESSARY. HOWEVER...MAY SEE SOMEWHAT OF A TEMP GRADIENT MON WHERE
SE OH AND NORTHERN WV ENDS UP WARMER THAN SOUTHERN AREAS DUE TO CLDS.
OVERALL LOOKING AT AN ABV NORMAL PERIOD THRU MIDWEEK...NOTHING NEW
THIS WINTER.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
ZONAL FLOW TO START TRANSITIONS TO NW FLOW THIS PERIOD AS LONG WAVE
TROUGH AMPLIFIES IN THE E. THIS LONG WAVE WILL LIKELY BE TRANSIENT
AGAIN THOUGH PER ONGOING LACK OF HIGH LATITUDE BLOCKING...TO WHICH
THE LACK OF DEEP PENETRATION OF ARCTIC AIR DOWN INTO THE EASTERN
CONUS IS ALSO ATTRIBUTABLE.
PERIOD STARTS DRY TUE NT WITH HIGH PRESSURE GIVING WAY TO A MOISTURE
STARVED COLD FRONT WITH NO INFLOW FROM THE S. THAT FRONT PASSES
EARLY WED...FOLLOWED BY A WAVE AND UPPER LEVEL S/W TROF THAT CROSS
WED INTO WEDNESDAY NT. CARRIED CHANCE POPS FOR THIS IN KEEPING WITH
HPC...WHICH FOLLOWS THE ECMWF AND THEN THE ECENS MEAN WHICH BECOMES
A GOOD REPRESENTATION OF THE MODEL AVERAGE LATER IN THE PERIOD.
WEAK SFC HIGH PRESSURE FOR THU ALTHOUGH ANOTHER UPPER LEVEL S/W TROF
ALSO CROSSES.
A STRONGER COLD FRONT DROPS DOWN FRI AS THE EASTERN CONUS LONG WAVE
TROF BEGINS TO SET UP. CARRIED THE CHANCE FOR PRECIPITATION WITH
THIS STRONGER FRONT ALTHOUGH MOISTURE WILL AGAIN BE LIMITED...AGAIN
KEEPING CLOSE TO HPC GUIDANCE.
ADJUSTED TEMPERATURES TO OR TOWARD HPC EARLY ON WHICH ENTAILED
HIGHER VALUES WED AND LOWER VALUES THU AND THU NT. WENT LOWER THAN
HPC BEYOND THAT IN DEFERENCE TO THE MEX AND ISC. AGAIN THOUGH THERE
IS SOME QUESTION AS TO HOW MUCH COLDER IT GETS ONCE THE SECOND FRONT
ROLLS THROUGH.
&&
.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
A LOW PRESSURE SYSTEM MOVING SOUTH OF THE REGION WAS CREATING
IFR/LIFR CONDITIONS. SOME DRIER AIR MOVING SOUTHWARD FROM EASTERN
OHIO WILL CAUSE SOME IMPROVING CONDITIONS IN THE SOUTHEAST OHIO AND
NORTHWESTERN WEST VIRGINIA...OTHERWISE...EXPECT THE IFR/LIFR
CONDITIONS TO CONTINUE THROUGH DAY BREAK. THE DRIER AIR WILL SLOWLY
PUSH SOUTHEASTWARD ACROSS THE REGION DURING THE DAY...ALLOWING FOR
CONDITIONS TO GRADUALLY CHANGE TO VFR FROM NORTHWEST TO SOUTHEAST
TODAY. VFR CONDITIONS CAN THEN BE EXPECTED THIS EVENING.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CEILINGS AND VISIBILITIES IMPROVING
COULD VARY.
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 SUN 02/05/12
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 M M M M M M M M M L L H
HTS CONSISTENCY M M M M M M M L L L L M
BKW CONSISTENCY L L M M M M M L L L L M
EKN CONSISTENCY L L L L L L L L L M M L
PKB CONSISTENCY M M M M M M L H H H H H
CKB CONSISTENCY H H H H H L L L M M H H
AFTER 06Z MONDAY...
IFR/LIFR POSSIBLE IN VALLEY FOG MONDAY MORNING...ESPECIALLY IN
MOUNTAIN VALLEYS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...RPY
SHORT TERM...30
LONG TERM...TRM
AVIATION...RPY
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
124 AM EST SUN FEB 5 2012
.SYNOPSIS...
LOW PRESSURE WILL TRACK SOUTH OF PENNSYLVANIA THROUGH THE MORNING.
HIGH PRESSURE WILL BE ACCOMPANIED BY MAINLY DRY AND MILD WEATHER
FOR MUCH OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
SECOND SHORTWAVE HAS LESS MOISTURE TO WORK WITH THAN PREVIOUS WAVE
ON SATURDAY DID. MUCH OF THE RADAR RETURNS OVER SOUTHERN PA SEEM
TO BE ALOFT AT THIS POINT...BUT ARE ONCE AGAIN TRYING TO MOISTEN
UP THE LOW/MID LEVELS. THE DRYING NERLY FLOW AT THE SFC WILL MAKE
IT TOUGH FOR ANYWHERE BUT THE HIGHEST TERRAIN OF SOMERSET/BEDFORD
CO TO PICK UP ANOTHER HALF INCH OF SNOW. WILL KEEP LIKELY POPS IN JUST
SOMERSET-BEDFORD-FULTON. RADAR TRENDS SUGGEST NR ZERO CHC OF
ADDITIONAL MEASURABLE SNOW NORTH OF THE TURNPIKE. TEMPS ON TRACK
TO DIP TO THE LOWER 20S IN THE NORTH...TO NR 30F OVR THE LOWER
SUSQ VALLEY.
PLENTY OF LOW LVL MOISTURE...COMBINED WITH CALM WIND...HAS ALLOWED
AREAS OF FOG TO FORM OVER SOUTHERN PA...WHICH WILL LIKELY PERSIST
UNTIL ARND DAWN. MCLEAR SKIES WILL ALSO LIKELY RESULT IN PATCHY
RAD FOG ACROSS THE N MTNS TOWARDS DAWN. HRRR SHOWS SFC RH/S
DROPPING TO NR 100PCT UP THERE BY 12Z.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM MONDAY/...
HIGH PRESSURE WILL BUILD IN FROM THE WESTERN GREAT LAKES AND OHIO
VALLEY...WITH THE RIDGE AXIS ARRIVING ACROSS CENTRAL PA IN THE
AFTERNOON HOURS. ANY SHSN IN THE SRN MTS WILL DISSIPATE AND SKIES
WILL EVEN GET BRIGHTER THERE LATER IN THE DAY AFTER THE FLOW
BECOMES MORE NORTHWEST THAN NORTHEAST. A VERY PLEASANT AFTERNOON
IS EXPECTED WITH MAX TEMPS RANGING FROM THE UPPER 30S IN THE
NORTHWEST TO THE MID 40S OVER THE SOUTHEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
NOT A LOT OF CHANGE THIS PACKAGE.
LEFT MENTION OF SNOW IN FAR NORTHERN PA FOR TUE...AS NEXT FRONT
DROPS SOUTHWARD.
TOOK OUT MENTION OF SNOW TUE NIGHT...AS SUPPORT FOR SNOW ALONG
FRONT WEAKENS.
DID TAKE OUT SNOW FOR WED FOR MOST OF THE AREA...BUT WENT
WITH CHC ALONG MD BORDER...AS MODELS HINT AT WAVE ON FRONT IN
SOUTHERN BRANCH...GIVEN SPLIT FLOW. SIMILAR SITUATION TO THE
CURRENT EVENT ACROSS SOUTH CENTRAL PA.
WENT WITH CHC POPS LATE THU INTO FRIDAY...AS AN UPPER LVL
TROUGH MOVES ACROSS THE AREA. AS WINDS GO MORE TO THE NW TO N
ON FRIDAY...LESS CHC OF SNOW SHOWERS AS THE DAY GOES ON.
VERY COLD AIR BUILDS INTO EASTERN CANADA LATE NEXT WEEK...
MODELS HINT THAT THE REAL COLD AIR STAYS NORTH OF PA...THUS
LEFT NEXT WEEKEND DRY AT THIS POINT...GIVEN LOCATON OF BEST
COLD AIR TO LIFT WARM AIR BACK NORTHWARD ALSO MODELS HINT THAT
ANY FRONTAL SNOW WOULD BE NORTH ANYWAY.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
BANDS OF LOW STRATOCU AND SNOW EMMINATING FROM LOW PRESSURE
TRACKING SOUTH OF PENNSYLVANIA WILL BRING LIFR TO VLIFR VSBYS AND
CIGS TO JST AND AOO THROUGH EARLY SUNDAY. AS THE LOW MOVES OFF TO
THE EAST DRYING WILL ARRIVE FROM NORTH TO SOUTH EARLY SUNDAY AS
HIGH PRESSURE BUILDS INTO THE REGION. VFR CONDS WILL RETURN WITH
FAIR WEATHER EXPECTED THROUGHOUT SUNDAY.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS. THU...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DANGELO
NEAR TERM...DANGELO/FITZGERALD
SHORT TERM...DANGELO/DEVOIR
LONG TERM...MARTIN
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
1035 PM CST SAT FEB 4 2012
.DISCUSSION.../ISSUED AT 830 PM CST/
UPDATED GRIDS TO REFLECT CURRENT TRENDS OF STRATUS DECK MOVING
SOUTHWARD OVER CWA...AS WELL AS FOG FORMING EARLIER THAN FORECAST.
LIGHT NORTHERLY FLOW AIDING IN ITS MOVEMENT SO NO REASON WHY IT
WON`T CONTINUE TO MOVE SOUTH. RUC MODEL ALSO BACKS CURRENT TREND.
MOVED CLOUD DECK AS FAR SOUTH AS KSUX AND THEN SLOWLY DISSIPATING
DECK POST SUNRISE ON SUNDAY. AS RESULT...I ALSO ADJUSTED A FEW LOW
TEMPERATURE FORECASTS AT THE SAME TIME.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
AREA OF IFR STRATUS CONTINUES TO DROP SOUTHWARD ACROSS THE AREA ON A
NORTHERLY/NORTHWESTERLY LOW LEVEL FLOW. ANTICIPATE THAT IT WILL NOW
MAKE IT ALL THE WAY INTO THE SOUTHERN PORTIONS OF THE FORECAST
AREA...THOUGH SOME UNCERTAINTY ON ARRIVAL AT KSUX...GENERALLY IN THE
08Z TO 09Z TIME FRAME. VISIBILITIES ARE ALSO BEGINNING TO DROP
THROUGH THE NORTHERN I 29 CORRIDOR INTO SOUTHWESTERN MINNESOTA...AND
ANTICIPATE LOCALIZED IFR VISBYS ACROSS THE AREA. IMPROVING
CONDITIONS EXPECTED AFTER 16Z ON SUNDAY.
&&
.PREV DISCUSSION.../ISSUED AT 315 PM CST/
WITH LAST OF THE CLOUDS FROM THE SOUTHERN SYSTEM MOVING SOUTHEAST OF
AREA THIS EVENING...PROBLEM WILL BE THE POTENTIAL REDEVELOPMENT OF
STRATUS AND FOG OVER THE AREA TONIGHT AS WINDS STEADILY BECOME
LIGHT. SEEMINGLY AMPLE LOW LEVEL MOISTURE WOULD SEEM TO POINT TO
REDEVELOPMENT BUT SUBSIDENCE/WARMING/DRYING ABOVE THE SURFACE IS
BECOMING MORE EVIDENT ALL THE TIME...SUCH AS IN THE LOWERED
DEWPOINTS AT PQN AND FSD WITH THE HEATING. ANY LOW LEVEL MOISTURE
WILL TEND TO BECOME SHALLOWER WITH TIME AND THINK THIS WILL BE
ENOUGH TO KEEP THE STRATUS FROM REDEVELOPING. WILL ALLOW FOR SOME
AREAS OF FOG TO DEVELOP BUT IT WILL HAVE TO BE SHALLOW. WOULD NOT BE
SURPRISED TO SEE IT ABSENT BUT FOG IN THESE CASES DOES NOT NEED VERY
DEEP MOISTURE AND COOLING TO DEVELOP. WILL RESTRICT IT TO LATE
TONIGHT. TEMPERATURES NOT MUCH OF A PROBLEM...SHOULD COOL GENERALLY
INTO THE LOWER 20S.
IF THERE IS ANY FOG IT SHOULD GO QUICKLY SUNDAY MORNING AND LEAVE A
PRETTY SUNNY DAY WITH TEMPERATURES REBOUNDING INTO THE 40S
EVERYWHERE...NOT JUST HERE AT FSD. FAIRLY LIGHT WINDS SHOULD SHOW A
SLOW TREND FROM NORTHWEST TO WEST AND SOUTHWEST. / WILLIAMS
UNORGANIZED SPLIT FLOW WILL DOMINATE FOR MUCH OF THE NEXT WEEK...
WITH LITTLE IN THE WAY OF PRECIP CHANCES SEEN FOR OUR AREA. SOUTHERN
AND NORTHERN STREAMS ATTEMPT TO PHASE LATE MONDAY NIGHT/TUESDAY WITH
MOST MODELS SPITTING OUT SOME VERY LIGHT QPF NEAR AND SOUTH OF THE
MISSOURI VALLEY. SOUNDINGS FOR OUR AREA SHOW DEEP DRY LAYER BENEATH
THE INCREASING MID CLOUD DECK SO WILL LEAVE FORECAST DRY FOR NOW...
THOUGH FLURRIES NOT OUT OF THE QUESTION IN SOUTHERN AREAS. TIMING OF
COLD FRONT ON MONDAY SEEMS TO HAVE SLOWED A BIT FROM PREVIOUS...SO
HAVE BUMPED TEMPS A FEW DEGREES ALONG/SOUTH OF I-90. POTENTIAL FOR
WARMING IN FAR SOUTHERN AREAS A LITTLE TRICKY...AS LOW LEVEL FLOW
AHEAD OF THE FRONT WILL BE COMING OFF FRESH DEEP SNOWPACK...BUT EVEN
ISOTHERMAL FROM 925MB WOULD YIELD LOWER 40S AND A FEW DEGREES ABOVE
THAT SHOULD BE ACHIEVABLE WITH MIXING AHEAD OF THE FRONT. BREEZY
CONDITIONS IN THE COLD ADVECTION ALONG WITH INCREASING CLOUDS MONDAY
NIGHT SHOULD HOLD TEMPERATURES UP IN THE UPPER TEENS TO MID 20S...
WITH LITTLE RECOVERY EXPECTED DESPITE CLEARING ON TUESDAY. LARGER
DIURNAL RANGE EXPECTED TUESDAY NIGHT/WEDNESDAY. SURFACE RIDGE
TUESDAY NIGHT WILL ALLOW FOR GOOD RADIATIVE COOLING...ESPECIALLY
WEST WHERE CLOUDS ARE MORE LIKELY TO CLEAR. SOUTH-SOUTHWEST FLOW
COMING OFF SNOWPACK ON WEDNESDAY WILL LIKELY TEMPER WARMING SOME...
BUT READINGS NEAR TO JUST ABOVE FREEZING OVER OUR BARE GROUND SEEM
REASONABLE.
TIMING OF ARCTIC PUSH...WITH 850MB TEMPERATURES IN THE TEENS BELOW
ZERO...LOOKS TO BE ON TARGET FOR THURSDAY/THURSDAY NIGHT TIME FRAME.
HOWEVER DISCREPANCIES ABOUND IN HOW FAR WEST THE COLD AIR WILL GET
AND HOW LONG IT WILL STICK AROUND...MAKING HIGHS FOR FRIDAY THE
BIGGEST QUESTION OF THE LONGER RANGE. 00Z SATURDAY 850MB TEMPS VARY
BY 10 DEGREES ACROSS VARIOUS DETERMINISTIC MODELS...AND BY CLOSER TO
20 DEGREES AMONG THE 12Z GFS ENSEMBLE MEMBERS...LEAVING QUITE A BIT
OF ROOM FOR LARGE ERRORS IN THIS PERIOD. HOWEVER...GIVEN CONTINUED
LACK OF SNOW AND RELATIVELY DRY AIRMASS IN WAKE OF SURFACE RIDGE
WHICH MOVES THROUGH THURSDAY NIGHT...WILL ERR TOWARD WARMER SIDE OF
GUIDANCE SPECTRUM. A LITTLE MORE WARMING EXPECTED FOR SATURDAY AS
MODELS SHOW BETTER CONSENSUS IN SHIFTING THE COLDER AIR OFF TO THE
EAST.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
355 AM CST SUN FEB 5 2012
.SHORT TERM (TODAY)...LARGE SCALE ATMOSPHERIC LIFT INCREASED
LAST EVENING IN RESPONSE TO AN UPPER LEVEL JET STREAK THAT LIFTED
TO THE NORTH OF THE AREA. WIDESPREAD SHOWERS/SCATTERED THUNDERSTORMS
CONTINUE EARLY THIS MORNING WITH MORE TO COME. LARGE AREA OF
CONVECTION MOVING NORTHEAST FROM DEEP SOUTH TEXAS THIS MORNING.
WATER VAPOR IMAGERY SHOWS ANOTHER ENERGETIC UPPER LEVEL JET STREAK
LIFTING NORTH-NORTHEAST OUT OF MEXICO. LATEST RUC SHOWS A 90 KNOT
25H JET MOVING INTO COAHUILA THAT WILL MOVE INTO CENTRAL TEXAS
THIS AFTERNOON. SOUTH TEXAS WILL AGAIN BE IN A REGION OF INCREASING
LIFT IN RESPONSE TO INCREASING UPPER LEVEL DIVERGENCE. FORECAST
SOUNDINGS CONTINUE TO SHOW ELEVATED UNSTABLE LAYER ABOVE 800 MBS
REMAINING OVER THE REGION THROUGH THE DAY. GFS/ECMWF/NAM SHOW THE
85H TROUGH AXIS OVER THE BRUSH COUNTRY WITH THE GOOD MOISTURE FLUX
CONVERGENCE MOVING FROM THE BRUSH COUNTRY THROUGH THE COASTAL BEND
THROUGH THE DAY. TIME-HEIGHT CROSS SECTIONS SHOW LIFT THROUGH A
LARGE LAYER THROUGH THE MORNING INTO MID AFTERNOON. WILL GO WITH
CATEGORICAL POPS FOR MOST OF THE AREA EXCEPT WESTERN BRUSH COUNTRY
WHERE WENT WITH LIKELY POPS. QPF FORECAST WAS A BLEND OF THE
CMC/ECMWF/SREF WITH AVERAGE OF A LITTLE OVER HALF OF AN INCH ALONG
THE COAST...BUT THERE WILL BE AREAS THAT COULD RECEIVE UP TO AN
INCH. PRECIPITABLE WATER VALUES WILL BE ABOVE 1 INCH BRUSH COUNTRY
AND BE NEAR 1.5 INCHES OVER THE GULF WATERS.
&&
.MARINE (TODAY THROUGH TONIGHT)...HIGH PRESSURE BUILDING INTO THE
AREA WILL KEEP WINDS A BIT STRONGER AND REMAIN IN SCA RANGE FOR
A LITTLE LONGER. EXTENDED SCA FOR THE BAYS UNTIL 20Z AND FOR THE
GULF WATERS UNTIL 03Z MONDAY. WIDESPREAD SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE DAY WITH A DECREASE IN COVERAGE THIS
EVENING.
&&
.LONG TERM (TONIGHT THROUGH SATURDAY)...PRECIP EXPECTED TO DIMINISH
TONIGHT AS UPPER DISTURBANCE EXITS THE AREA. THE CANADIAN AND NAM
KEEP LIGHT PRECIP IN THE FCST ON MON...HOWEVER LEANED TOWARD THE
DRIER ECMWF AND GFS. MODELS CONTINUE TO PROG A SERIES OF EMBEDDED
SHORT WAVES TO TRACK ACROSS THE REGION THROUGH THE WEEK AHD OF A
POTENT CUT OFF LOW. MODELS DIFFER ON QPF EACH DAY AND THEY DIFFER ON
LOCATION OF HEAVIEST PRECIP. KEPT WITH THE CHC POPS DVLPG ACROSS THE
SRN CWA BY TUE NITE AND SHIFTING INTO THE WESTERN HALF OF THE CWA
THRU WED. THEN AS THE UPPER LOW MOVES ACROSS MEX TOWARD TX...UPPER
DIFFLUENCE INCREASES. THE HIGHEST PWATS ARE PROGD FOR THU AND LOW
LEVEL MOISTURE CONVERGENCE INCREASES AS A COLD FRONT/REINFORCING
HIGH PRESSURE PUSHES S INTO THE AREA. THEREFORE KEPT THE 50 POPS
ACROSS THE WEST DUE TO PROXIMITY TO UPPER LOW/BEST DYNAMICS. KEPT A
BROADBRUSHED 30 POP FOR FRI AS MODELS BEGIN TO DIVERGE ON
PLACEMENT/STRENGTH OF UPPER LOW AND CORRESPONDING PRECIP. GFS SHOWS
A DRIER FCST BY SAT AFTERNOON AS THE UPPER SYSTEM PUSHES THRU THE
AREA AND A NW FLOW ALOFT DVLPS. THE ECMWF IS A TAD SLOWER. WENT WITH
A BROADBRUSHED 20 POP ON SAT FOR NOW. AS FOR TEMPS...WENT WITH A
WARMING TREND MON THRU THU AHD OF COLD FRONT...THEN A SLIGHT COOLING
TREND FRI AND SAT IN THE WAKE OF THE COLD FRONT. OVERALL TEMPS ARE
PROGD TO BE GENERALLY BELOW NORMAL THROUGH THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 50 44 60 45 65 / 80 40 10 10 20
VICTORIA 50 41 58 42 64 / 80 20 10 10 20
LAREDO 54 46 61 46 66 / 60 10 10 10 10
ALICE 51 43 59 42 65 / 80 30 10 10 20
ROCKPORT 51 46 60 49 66 / 80 40 10 10 20
COTULLA 52 41 59 42 64 / 70 10 10 10 10
KINGSVILLE 50 43 59 44 66 / 80 40 10 10 20
NAVY CORPUS 52 46 60 48 67 / 80 40 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR.
&&
$$
TMT/89...SHORT TERM
TE/81...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
249 AM CST SUN FEB 5 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY
249 AM CST SUN FEB 5 2012
ANOTHER DAY OF TRYING TO FORECAST STRATUS AND TEMPERATURES IS ON
DECK FOR TODAY FOLLOWED BY A COLD FRONT THAT WILL COME THROUGH
MONDAY NIGHT.
ODDLY SITUATED MID LEVEL PATTERN IN PLACE WITH A TROUGH AND TWO
EMBEDDED VORT MAXES EXTENDING WEST FROM THE EASTERN GREAT LAKES
TOWARD NEVADA WITH A CUT OFF RIDGE SET UP ALONG THE US/CANADA
BORDER FROM THE PACIFIC NORTHWEST GOING EAST TOWARD THE DAKOTAS.
AT THE SURFACE...A BROAD RIDGE OF HIGH PRESSURE IS IN PLACE ALONG
THE EASTERN ROCKIES/WESTERN PLAINS WITH A RIDGE AXIS EXTENDING EAST
THROUGH THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES REGION.
TWO MAIN POCKETS OF STRATUS REMAIN TRAPPED UNDER THE 950-900MB
INVERSION WITH ONE ADVANCING SOUTH-SOUTHEAST ACROSS MINNESOTA AND
ANOTHER OVER THE UPPER PENINSULA OF MICHIGAN AND NORTHEAST
WISCONSIN ADVANCING SOUTH-SOUTHWEST ACROSS EASTERN WISCONSIN.
WHAT HAPPENS WITH THIS CLOUD DECK TODAY IS THE MAIN QUESTION SINCE
IT WILL HAVE A DIRECT IMPACT ON HOW HIGH TEMPERATURES GET ONCE
AGAIN. BASED ON THE 05.06Z HRRR AND RECENT IR SATELLITE
TRENDS...IT LOOKS LIKE THE MINNESOTA STRATUS WILL HOLD ON THROUGH
THE MORNING ACROSS MN/IA WITH THE WISCONSIN STRATUS REACHING THE
MISSISSIPPI RIVER BY LATE MORNING. WHILE SOME HOLES WILL LIKELY
FORM THROUGH THE DAY...WENT A BIT ON THE PESSIMISTIC SIDE FOR
CLOUD COVER TODAY WHICH IN TURN WILL KEEP TEMPERATURES DOWN.
WHERE THE HOLES DO OPEN UP TODAY...HIGHS WILL LIKELY END UP IN THE
LOW TO MID 40S WITH TEMPERATURES IN THE 30S UNDER THE CLOUD DECK.
SOME INCREASING WESTERLY WINDS WILL PUSH DOWN ACROSS NORTHERN
WISCONSIN TODAY AND TONIGHT AND MAY HELP TO MIX OUT SOME OF THIS
LOW STRATUS AND CLEAR SKIES FROM THE NORTH.
THE FOCUS THEN GOES TO A COLD FRONT THAT WILL DROP THROUGH THE
REGION ON MONDAY NIGHT. AHEAD OF IT...WARM AIR ADVECTION AND
INCREASED LOW LEVEL MIXING WILL LEAD TO SUNNY SKIES AND A MILD DAY
WITH HIGHS LIKELY TO REACH THE MID TO UPPER 40S. THE TIMING OF THE
COLD FRONT PASSAGE MONDAY AFTERNOON AND NIGHT IS PRETTY CONSISTENT
BETWEEN THE 05.00Z MODEL SOLUTIONS WITH THE FRONT GETTING SOUTH
OF LA CROSSE AND ROCHESTER BEFORE 00Z TUESDAY AND SOUTH OF THE
WISCONSIN STATE LINE BY 06Z. LOW LEVEL CLOUD COVER WILL BE ON THE
INCREASE AS THE FRONT PASSES WITH THE QUESTION NOW BEING WHETHER
ANY FLURRIES WILL BE POSSIBLE AS THIS FEATURE PASSES. 05.00Z
NAM/GFS SOUNDINGS ARE TRENDING TOWARD HAVING A DEEPER LOW LEVEL
MIXED TEMPERATURE PROFILE WITH A DECENT AMOUNT OF MOISTURE AND
LIFT IN THIS LAYER AVAILABLE TO POSSIBLY PRODUCE SOME SNOWFLAKES
AS THE LAYER COOLS TOWARD -10/-12C. CONFIDENCE IS NOT THAT HIGH AT
THIS POINT TO PUT THESE POSSIBLE FLURRIES IN THE FORECAST...BUT IT
IS AT LEAST SOMETHING TO KEEP TABS ON OVER THE NEXT FEW DAYS.
A BROAD RIDGE OF HIGH PRESSURE WILL MOVE INTO THE UPPER
MISSISSIPPI RIVER VALLEY TUESDAY INTO WEDNESDAY AND WILL KEEP
TEMPERATURES DOWN TOWARD NORMAL INTO MID WEEK.
.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY
249 AM CST SUN FEB 5 2012
FOCUS IN THE EXTENDED CONTINUES TO BE WITH A COLD FRONT THAT IS
PROGGED TO COME THROUGH LATER IN THE WEEK. THE 05.00Z GFS
CONTINUES ITS TREND OF BEING THE FASTEST WITH THIS FEATURE AND
BRINGS IT THROUGH EARLY ON THURSDAY WHILE THE 05.00Z ECMWF IS
STILL SLOWER AND DOES NOT DROP THE FRONT THROUGH UNTIL FRIDAY.
INTRODUCED SOME LIGHT SNOW CHANCES ACROSS NORTH CENTRAL WISCONSIN
WITH THIS FEATURE AS THE GFS HAS BEEN SHOWING SOME POSSIBLE QPF UP
THERE THE PAST FEW RUNS.
OTHERWISE DIFFERENCES CROP UP GOING INTO THE WEEKEND WITH HOW LONG
THE COLD LOW LEVEL AIR REMAINS IN PLACE WITH THE 05.00Z GFS NOW
HOLDING ONTO 850MB TEMPERATURES BELOW -20C INTO THE WEEKEND WHILE
THE 05.00Z ECMWF PUSHING THE COLD AIR RAPIDLY OFF TO THE EAST LOW
LEVEL WARM AIR ADVECTION KICKING IN BY SATURDAY. GIVEN THESE
DISCREPANCIES...CONFIDENCE IS NOT ALL THAT HIGH IN HOW
TEMPERATURES WILL END UP TOWARD THE LATER PORTION OF THE FORECAST
PACKAGE.
&&
.AVIATION...THROUGH 06Z MONDAY
1133 PM CST SAT FEB 4 2012
A LARGE AREA OF STRATUS OVER MINNESOTA WAS PUSHING
SOUTHEAST...WITH THE LEADING EDGE EXTENDING FROM NEAR KONA...TO
KCCY. QUITE A BIT OF REPORTS OF CEILINGS IN THE LIFR CATEGORY
UNDER THE STRATUS AT 05Z. VISIBILITIES ON THE OTHER HAND WERE
RANGING FROM 1/2SM TO 5SM. 05.04Z RUC 975MB RELATIVE HUMIDITY PROG
SHOWS THIS STRATUS TO CONTINUE TO ADVECT EASTWARD BLANKETING BOTH
TAF SITES THROUGHOUT THE NIGHT. KLSE WILL LIKELY SEE THE STRATUS
BETWEEN 06Z-07Z. EXPECT LIFR CONDITIONS AT KRST AND IFR CONDITIONS AT
KLSE THROUGH AROUND 16Z. BY THAT TIME BOTH THE 05.04Z RUC AND
05.00Z NAM BUFKIT SOUNDINGS SHOW ENOUGH MIXING TO SCATTER OUT THE
CLOUDS. VFR CONDITIONS WILL THEN PREVAIL INTO THE EVENING HOURS.
COULD SEE SOME MVFR VISIBILITIES DEVELOP BETWEEN 04Z-06Z SUNDAY AS
COLUMN COOLS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
249 AM CST SUN FEB 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS MILWAUKEE/SULLIVAN WI
1053 PM CST SAT FEB 4 2012
.UPDATE...
EXPECT SKIES TO REMAIN CLEAR TONIGHT WITH SOME PATCHY FOG DURING
THE EARLY MORNING HOURS.
WILL HAVE TO WATCH THE STRATOCUMULUS SHIELD THAT IS PUSHING SOUTH
ACROSS NORTHERN LAKE MICHIGAN. THE HRRR TAKES THESE CLOUDS INTO
MUCH OF SOUTHERN WISCONSIN AFTER SUNRISE.
&&
.AVIATION/06Z TAFS/...
EXPECT CLEAR SKIES EARLY THIS MORNING WITH AREAS OF MVFR VSBYS IS
FOG AND SOME PATCHY IFR VSBYS AROUND SUNRISE.
MAIN PROBLEM IS WITH MVFR STRATOCUMULUS DECK PUSHING SOUTH ACROSS
NORTHERN LAKE MICHIGAN BEHIND THE 500 MB TROF MOVING ACROSS THE
GREAT LAKES. THE HRRR AND RUC TAKE THESE CLOUDS INTO MUCH OF
SOUTHERN WISCONSIN. NAM/GFS DO NOT. WILL LEAN TOWARD THE HIGH RES
MODELS SINCE THE HRRR HAS BEEN DOING A GOOD JOB WITH THE FIRST 4
HOURS OF THE FORECAST IN THE SOUTHERN MOVEMENT.
WILL REFLECT THIS IN THE 06Z TAFS.
&&
.PREV DISCUSSION... /ISSUED 226 PM CST SAT FEB 4 2012/
TONIGHT AND SUNDAY...FORECAST CONFIDENCE MEDIUM.
INFLUENCE OF HIGH PRESSURE ACROSS THE NORTHERN AND CENTRAL PLAINS
DURING THIS TIME WILL BRING QUIET WEATHER TO THE AREA. SKIES SHOULD
REMAIN MOSTLY CLEAR ACROSS THE AREA TONIGHT AND SUNDAY...WITH DRY
AIRMASS IN PLACE. RUC/NAM FORECAST SOUNDINGS TRYING TO SHOW A LOW
STRATUS CLOUD DECK FORMING TONIGHT...BUT THESE MODELS HAVE BEEN
OVERFORECASTING THESE DECKS ALL WINTER AND DO NOT BUY IT WITH DRY
AIR IN PLACE.
THERE MAY BE SOME LOW CLOUDS THAT DRIFT INTO THE FAR WESTERN
COUNTIES LATER TONIGHT...ASSOCIATED WITH LOW CLOUD DECK TO THE
WEST. SOME LOW STRATUS MAY ALSO TRY TO WORK INTO THE FAR NORTHEAST
COUNTIES LATER TONIGHT...BUT MOST SHOULD REMAIN TO THE NORTHEAST.
TEMPERATURES TONIGHT SHOULD FALL INTO THE 20S ACROSS THE AREA WITH
MOSTLY CLEAR SKIES AND RELATIVELY LIGHT WINDS. HIGHS SUNDAY SHOULD
RISE INTO THE LOWER 40S AT LEAST...GIVEN SIMILAR CONDITIONS TO
TODAY. WINDS TURNING WEST SUNDAY AFTERNOON WITH LITTLE TO NO
SNOWPACK MAY HELP TEMPERATURES RISE EVEN MORE...INTO THE MID 40S.
SUNDAY NIGHT AND MONDAY...FORECAST CONFIDENCE IS HIGH.
THE SURFACE RIDGE AXIS BEGINS TO SHIFT SOUTH IN RESPONSE TO A
TROF/COLD FRONT DROPPING DUE SOUTH OUT OF CANADA. THE TROF AXIS
WILL STAY NORTH OF THE CWA THROUGH MONDAY AFTERNOON WITH A
DEVELOPING WESTERLY FLOW AHEAD OF IT BRINGING IN A DECENT THERMAL
RIDGE. ANY CLOUDS WITH THE CANADIAN SYSTEM SHOULD BE MAINLY POST
FRONTAL...SO PLENTY OF SUNSHINE EXPECTED ON MONDAY. GIVEN THE LACK
OF DEEP SNOW COVER OVER MUCH OF THE CWA...WE/RE STILL LOOKING AT
TEMPS ABOVE MOS GUIDANCE. CURRENT VISIBLE SATELLITE IMAGE SHOWS
THE FUZZY WHITE INDICATIONS OF A LIGHT SNOW COVER ROUGHLY WEST OF
A LINE STRETCHING FROM FOND DU LAC TO DARLINGTON. THERE IS STILL
OFFICIALLY 1 INCH ON THE GROUND AT THE MADISON AIRPORT. NOT ENOUGH
TO REALLY HOLD BACK THOSE TEMPS.
MONDAY NIGHT AND TUESDAY...FORECAST CONFIDENCE IS MEDIUM.
THE COLD FRONT COMES THROUGH EARLY MONDAY NIGHT WITH ALL THE
MODELS SHOWING A DECENT AMOUNT OF LOW LEVEL MOISTURE/CLOUD COVER
IN IT/S WAKE. THE NAM GENERATES SOME LIGHT QPF LATE MONDAY NIGHT
AND TUESDAY AS IT SNEAKS IN SOME DEEPER MOISTURE WITH AN ARRIVING
UPPER LEVEL SHORTWAVE SHORTLY AFTER THE FRONT MOVES THROUGH. THE
NAM IS THE FARTHEST NORTH WITH THIS FEATURE AND DEFINITELY THE
MOST GENEROUS WITH THE MOISTURE. AT THIS POINT...WILL LEAVE ANY
SNOW MENTION OUT OF THE FORECAST...EXCEPT FOR NEAR LAKE MICHIGAN
IN THE FAR SOUTHEAST. HERE...IT LOOKS LIKE THE DEVELOPING NORTHEAST
FLOW COMBINED WITH DELTA/TS AROUND 13-14 WILL BE ENOUGH TO
GENERATE SOME LAKE EFFECT SNOW SHOWERS ON TUESDAY. THE INVERSION
IS LIMITED AT ONLY 5 TO MAYBE 6KFT...SO NOTHING MAJOR. LOOKING AT
LESS THAN AN INCH.
WEDNESDAY...FORECAST CONFIDENCE IS MEDIUM.
HIGH PRESSURE SETTLES BACK IN FOR QUIET BUT COOLER WEATHER.
THURSDAY THROUGH SATURDAY...FORECAST CONFIDENCE IS MEDIUM.
THE GFS AND THE ECMWF HAVE ANOTHER COLD FRONT SWEEPING THROUGH
SOMETIME ON THURSDAY...TIMING IS A BIT OUT OF SYNC. THIS IS WITH A
LOW PRESSURE SYSTEM TRACKING ACROSS THE LAKE SUPERIOR AREA. RIGHT
NOW...MOISTURE LOOKS QUESTIONABLE FOR ANY PRECIP...SO THINGS ARE
DRY FOR NOW. BUT SMALL POPS MAY END UP BEING INTRODUCED LATER ON
FOR THIS SYSTEM. THIS ALSO SIGNALS ANOTHER SHOT OF COLD AIR...THIS
ONE CERTAINLY MORE ARCTIC LIKE. COLD HIGH PRESSURE BUILDS IN
QUICKLY BY THURSDAY NIGHT. HIGHS LATE NEXT WEEK WILL ONLY BE IN
THE 20S...BUT THIS IS ACTUALLY A MORE NORMAL HIGH FOR THIS TIME OF
YEAR. SO...OUR ARCTIC BLAST WILL ONLY PUSH TEMPS DOWN TO NORMAL
LEVELS. WHAT A WINTER.
AVIATION/00Z TAFS/...
ANY LINGERING LAKE EFFECT CLOUDS SHOULD MIX OUT AT MILWAUKEE AND
KENOSHA BY LATE THIS AFTERNOON...AS LOW LEVEL WINDS BACK TO THE
NORTH. ONLY SCATTERED CLOUDS AT WORST ARE EXPECTED.
INFLUENCE OF HIGH PRESSURE TO THE WEST OF THE AREA TONIGHT AND
SUNDAY WILL BRING VFR CONDITIONS WITH MOSTLY CLEAR SKIES. LIGHT
NORTHWEST WINDS TONIGHT WILL BECOME WEST BY SUNDAY AFTERNOON.
MARINE...
BRISK NORTHEAST WINDS AND HIGH WAVES ARE POSSIBLE ON TUESDAY...IN
THE WAKE OF A COLD FRONTAL PASSAGE. A TIGHT PRESSURE GRADIENT BEHIND
THE FRONT WOULD COMBINE WITH GOOD LOW LEVEL MIXING OF WINDS TO BRING
THESE CONDITIONS. THE HIGH WAVES MAY LINGER INTO TUESDAY NIGHT.
&&
.MKX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
LM...NONE.
&&
$$
UPDATE...HENTZ
TONIGHT/SUNDAY AND AVIATION/MARINE...WOOD
SUNDAY NIGHT THROUGH SATURDAY...DAVIS
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
730 AM MST SUN FEB 5 2012
.UPDATE...QUICK UPDATE TO INCREASE POPS ACROSS THE SOUTHWEST SAN
JUANS AND ADJACENT SOUTHERN VALLEYS WHERE SCATTERED SNOW SHOWERS
CONTINUE. ACCUMULATIONS WILL BE ON THE LIGHT SIDE...BUT WEBCAMS
INDICATING SOME IMPACT ON ROAD SURFACES. LATEST RUC SUGGESTS THIS
ACTIVITY WILL CONTINUE FOR A FEW MORE HOURS IN SHALLOW UPSLOPE
FLOW INTO THE SAN JUANS.
&&
.PREV DISCUSSION /ISSUED 415 AM MST SUN FEB 5 2012/...
SHORT TERM /TODAY THROUGH MONDAY NIGHT/...
CUT-OFF UPPER LOW WAS FORMING OVER WRN UT EARLY THIS MORNING IN AN
ELONGATED AREA OF LOW PRESSURE THAT STRETCHED FROM NV TO KS. THIS
UPPER LOW WILL STAY OVER UT THROUGH TONIGHT...WHEN A SHORTWAVE
DROPPING OUT OF CENTRAL CANADA AND A PACIFIC TROUGH REACHING THE
COAST FINALLY BEGIN TO PULL/PUSH IT EASTWARD ACROSS COLORADO ON
MONDAY-MONDAY NIGHT. THIS WILL KEEP AREAS OF CLOUDS AND A CHANCE OF
SNOW SHOWERS PRESENT THROUGH MONDAY NIGHT...AND MODELS ARE IN GOOD
AGREEMENT ON THIS SCENARIO. EMBEDDED DISTURBANCES ROTATING
COUNTERCLOCKWISE AROUND THE LOW WILL CROSS SE UT/SW CO AND FOCUS THE
CHANCE OF PRECIP MOSTLY ACROSS THE SOUTH HALF OF OUR FORECAST AREA.
THE BEST CHANCE LOOKS TO BE SUNDAY NIGHT AND MONDAY WHEN PERHAPS THE
MOST ENERGETIC DISTURBANCE PASSES. MOISTURE SHOULD BE LIMITED AS
THERE IS NO MOISTURE TAP TO THIS SYSTEM...BUT TEMPERATURES ALOFT
WILL BE NEAR OR IN THE FAVORABLE REGIME FOR SNOW CRYSTAL
GROWTH...AND SNOW SHOWERS COULD PRODUCE LOCALIZED ACCUMULATIONS OF A
COUPLE INCHES OVER THE SOUTHERN AND CENTRAL MOUNTAINS. SNOW CHANCES
WILL BE ON THE DECREASE MONDAY NIGHT AS THE LOW MOVES BY.
TEMPERATURES LOOK TO RUN NEAR PERSISTENCE TO A FEW DEGREES COOLER.
LONG TERM /TUESDAY THROUGH SATURDAY/...
GOOD AGREEMENT BETWEEN THE MEDIUM RANGE MODELS THROUGH THE ENTIRE
LONG TERM PERIOD. STRONG PACIFIC WAVE BREAKS OFF FROM THE MAIN
WESTERLIES AND DIVES SOUTHEAST ALONG THE CALIFORNIA AND BAJA
COAST ON WEDNESDAY AND THURSDAY...MISSING OUR FORECAST AREA ALTHOUGH
SOUTHEAST UTAH MAY SEE AN INCREASE OF CLOUDS. BUT THERE ARE SOME
SUBTLE DIFFERENCES THAT DOES HAVE SMALL IMPLICATIONS FOR OUR FORECAST
AREA. THE GFS SHOWS SOME SPOTTY LIGHT PCPN WITH A WEAK SHORT WAVE
BRUSHING NW COLORADO ON WEDNESDAY AFTERNOON AND EVENING. THE
LATEST ECMWF SHOW A SIMILAR SOLUTION BUT THE SPOTTY PCPN OCCURS THE
NEXT DAY. THE CANADIAN MODEL SHOWS STRONGER PACIFIC ENERGY
UNDERCUTTING THE STRONG AMPLIFIED RIDGE OVER WRN CANADA. NONE OF
THESE SOLUTIONS CAN BE CONSIDERED A SIGNIFICANT EVENT...BUT
SUGGEST THAT THE UPCOMING WEEK MAY NOT BE COMPLETELY DRY. RUN TO RUN
MODEL CONSISTENCY CAN BE BETTER AND BELIEVE THAT FUTURE MODEL
SOLUTIONS WILL OFFER MORE DIFFERENCES. EXTENDED GUIDANCE POPS
STAY BELOW 15 PERCENT AND WILL NOT DEVIATE FROM THIS AT THIS
TIME...ESSENTIALLY KEEPING THE GOING FORECAST DRY THROUGH DAYS 3
THROUGH 7. CONFIDENCE IS SO-SO AND IF MODELS SHOW SOME CONSISTENCY
WITH THE PASSING SHORT WAVE WEDNESDAY NIGHT AND THURSDAY TIME
FRAME...THEN CHANCE POPS FOR NW COLORADO WILL NEED TO BE
INTRODUCED.
&&
.AVIATION /FOR 12Z TAF ISSUANCE/...
SNOW SHOWERS WILL INCREASE OVER THE MOUNTAINS THIS AFTERNOON AND
WILL RESULT IN AREAS OF MOUNTAIN OBSCURATION...ESPECIALLY OVER THE
SAN JUAN MOUNTAINS. THE CHANCES FOR LESS THAN VFR CONDITIONS AT
AREA MOUNTAIN AIRPORTS WILL RANGE FROM 30 TO 40 PERCENT FOR KASE
AND KEGE.
KDRO AND KPSO...SCATTERED SNOW SHOWERS WITH A 40 TO 50 PERCENT
CHANCE THAT MVFR CIGS AND VIS WILL OCCUR TODAY AND TONIGHT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
UPDATE.......JDC
SHORT TERM...JAD
LONG TERM....PF
AVIATION.....TGJT
AREA FORECAST DISCUSSION
NWS LINCOLN IL
524 AM CST SUN FEB 5 2012
.DISCUSSION...
ISSUED 240 AM CST SUN FEB 5 2012
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL U.S. EARLY THIS
MORNING...WITH WATER VAPOR IMAGERY SHOWING IT CENTERED NEAR KANSAS
CITY...WITH A SECOND LOW FURTHER WEST ACROSS UTAH. CLEARING LINE
HAS BEEN QUICKLY MOVING SOUTH ACROSS THE NORTHERN CWA THE LAST FEW
HOURS...AND WAS JUST SOUTH OF THE I-74 CORRIDOR AT 2 AM. INITIAL
FORECAST CHALLENGE WILL BE WITH CLEARING TREND AND FOG POTENTIAL
EARLY ON...AS CLOUDS BREAK IN AREAS THAT HAD DECENT RAINFALL THE
LAST 24-36 HOURS. HOWEVER...THE PRIMARY FORECAST ISSUE WILL BE
WITH TREND FOR COLD WEATHER TOWARD THE END OF THE WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
LATEST HRRR NOT TOO FAR OFF WITH CURRENT POSITIONING OF THE
STRATUS...AND SHOWS MUCH OF THE CWA SHOULD BE STRATUS-FREE BY LATE
MORNING. NORTHERN CWA IS MOST VULNERABLE FOR SOME FOG EARLY...WITH
LACON CURRENTLY REPORTING 3/4 MILE AND BLOOMINGTON 1-3/4 MILE AS
THE CLOUDS HAVE BROKEN. SO FAR NOTHING NORTH OF THERE IS GETTING
OUT OF HAND YET DESPITE A LONGER CLEAR PERIOD...SO WILL MAKE A
LAST MINUTE DECISION ON WHETHER TO CONTINUE FOG POTENTIAL BEYOND
SUNRISE.
MISSOURI UPPER LOW PROGGED TO DRIFT SOUTHEAST TO THE LOWER OHIO
VALLEY BY TONIGHT. ANY RESIDUAL LIGHT RAIN/DRIZZLE WILL CONTINUE
TO SHRINK WITH THIS LOW...AND WILL LIKELY ONLY MENTION IT IN THE
FAR SOUTHEAST FOR EARLY TODAY. SURFACE HIGH PRESSURE RIDGING
EASTWARD POSES ANOTHER CONCERN FOR LOW CLOUDS/FOG TONIGHT. LATEST
SREF GRAPHICS SHOWING THE NORTHWEST CWA BEING OVERSPREAD BY LOWER
STRATOCUMULUS AFTER MIDNIGHT...LASTING UNTIL ABOUT MID-MORNING
MONDAY. GIVEN THAT THIS AREA SHOULD SEE DECENT SUNSHINE MUCH OF
TODAY TO HELP DRY THINGS OUT...AM NOT OVERLY CONFIDENT IN THIS
CLOUD SCENARIO AT THE MOMENT. FOR NOW...WILL GO WITH PARTLY CLOUDY
CONDITIONS ACROSS THE NORTHWEST TONIGHT AND MAINLY CLEAR
ELSEWHERE...WITH THE DAY SHIFT MAKING ANY FURTHER ADJUSTMENTS AS
THE DAYTIME TRENDS PLAY OUT.
LEFTOVER CUTOFF ENERGY OVER THE CENTRAL ROCKIES SHOULD WEAKEN AND
GET PICKED UP BY A TROUGH MOVING ALONG THE CANADIAN BORDER MONDAY
NIGHT AND TUESDAY. NOT A LOT OF MOISTURE AVAILABLE OVERHEAD WHEN
IT ARRIVES...BUT SOME RESIDUAL MOISTURE ACCOMPANYING THE LEFTOVER
ENERGY IS ENOUGH TO WARRANT SLIGHT CHANCE POPS FOR TUESDAY AND
TUESDAY NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY...
QUIET WEATHER EXPECTED MIDWEEK AS HIGH PRESSURE DRIFTS ACROSS THE
MIDWEST. MAIN CONCERN REMAINS WITH THE AMOUNT OF ARCTIC AIR THAT
WILL BE DROPPING SOUTHEASTWARD LATE IN THE WEEK. GFS BRINGS 850 MB
TEMPERATURES OF -16C ACROSS MOST OF THE CWA BY FRIDAY EVENING...
WHILE ECMWF GIVES US MORE OF A GLANCING BLOW WITH THE CORE OF THE
COLDER AIR CLOSER TO THE GREAT LAKES. HAVE BEGUN TO TREND DOWNWARD
WITH THE TEMPERATURE FORECASTS AS THE MAIN IDEA HAS BEEN
PERSISTENT FOR A COUPLE DAYS NOW...BUT NOT AS AGGRESSIVELY AS THE
GFS WOULD INDICATE...WHICH GIVES THE NORTHERN CWA A STRUGGLE TO
REACH 20 DEGREES ON FRIDAY. THAT MAY BE TOUGH WITHOUT ANY SNOW ON
THE GROUND...BUT WE SHOULD STILL SEE SOMEWHAT OF A COLD SNAP IN
AN OTHERWISE MILD WINTER.
GEELHART
&&
.AVIATION...
ISSUED 515 AM CST SUN FEB 5 2012
SEVERAL FORECAST CONCERNS THIS PERIOD WITH THE MAIN SHORT TERM
CONCERN BEING WITH THE FOG POTENTIAL THRU 15Z AND MOVEMENT OF IFR
CIGS JUST SOUTH OF OUR TAF SITES. SECOND CONCERN WILL BE TRACK OF
MVFR/IFR CIGS ACRS NRN IOWA AND OVER PARTS OF NE IL EARLY THIS
MORNING.
BACK-EDGE OF LOWER CLOUDS HAS SHIFTED JUST SOUTH OF SPI AND DEC
AS OF 10Z. EXPECT THE SLOW SOUTH MOVEMENT OF THESE CLOUDS TO
CONTINUE WITH SOME RAGGED MID LEVEL CLOUDS ACRS THE REMAINDER
OF THE FCST AREA. WITH THE RESIDUAL LOW LEVEL MOISTURE IN PLACE
FROM THE RAIN YESTERDAY AND CLEARING SKIES...PATCHY FOG WAS
PREVALENT OVER THE AREA. WILL CONTINUE WITH A TEMPO GROUP FOR
FOG THRU 15Z AND THEN VFR CONDITIONS ARE EXPECTED THRU LATE THIS
AFTERNOON. WITH THE LOW LEVEL MOISTURE IN PLACE AND SUNSHINE
EXPECTED TODAY...WE SHOULD SEE AT LEAST A SCATTERED CU FIELD
DEVELOP DESPITE THE SIGNIFICANT DRYING TAKING PLACE ABOVE 850 MB.
OUR ATTENTION THEN WILL TURN TO THE LOWER CLOUDS TO OUR NORTH AND
NORTHWEST. SHORT RANGE MODELS SUGGEST THE POTENTIAL FOR SOME OF
THE LOWER CIGS TO EDGE INTO WESTERN IL BY MID OR LATE THIS AFTN
AND EARLY THIS EVENING. CONFIDENCE RATHER LOW REGARDING MOVEMENT
OF THE CLOUD DECK LATER THIS AFTN AS LOW LEVEL WIND PROFILES
INDICATE WINDS WILL BACK FROM THE CURRENT NORTHERLY DIRECTION MORE
INTO THE WEST LATE TODAY...WHICH MAY AID IN MORE OF AN EASTWARD
TRAJECTORY TO THE IFR/MVFR CIGS CURRENTLY OVER IOWA. THAT WILL
HAVE TO BE WATCHED IN LATER FORECASTS...BUT FOR NOW WILL HOLD ON
TO THE VFR CONDITIONS THRU LATE THIS AFTN AND THEN INTRODUCE A
SCATTERED CLOUD GROUP AT AROUND 1500 FEET AT PIA LATER TODAY.
SURFACE WINDS WILL CONTINUE FROM A NORTHERLY DIRECTION TODAY AT
AROUND 10 KTS...AND THEN BACK INTO THE NORTHWEST AND THEN WEST
LATE THIS AFTN AND EVENING...WITH SPEEDS AFTR 00Z DROPPING OFF
TO AROUND 5 KTS OR LESS.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
932 AM EST SUN FEB 5 2012
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.
&&
.NEAR TERM /TODAY/...
WITH VISIBILITIES AROUND HALF A MILE OR LESS AT TIMES IN THE
NORTHWEST COUNTIES AND BELOW FREEZING TEMPERATURES ADDED A
FREEZING FOG ADVISORY EARLIER THAT RUNS THROUGH 10 AM FOR THAT
AREA...WITH THE MAIN CONCERNS BEING VISIBILITY RESTRICTIONS FOR
TRAVELERS AS WELL AS SLICK SPOTS DEVELOPING ON UNTREATED
ROADWAYS...ESPECIALLY BRIDGES AND OVERPASSES. ALSO ADDED SOME
CLOUD COVER FOR THE MORNING ACROSS THE CENTRAL AND SOUTH BASED ON
SATELLITE LOOP...BUT THIS SHOULD BE DISSIPATING IN THE 10 AM TO
NOON TIMEFRAME. PREVIOUS DISCUSSION FOLLOWS...
LIGHT PRECIP AND DRIZZLE RAPIDLY DECREASING IN COVERAGE TO THE
SOUTHEAST OF THE INDY METRO EARLY THIS MORNING...AND EXPECT IT TO BE
CLEAR OF THE FORECAST AREA BY 09-10Z. BACK EDGE OF LOWER CLOUDS ALSO
RAPIDLY DROPPING SOUTH AS DRIER AIR SPREADS INTO THE LOWER GREAT
LAKES. TEMPS WERE HOVERING NEAR FREEZING ACROSS FAR NORTHERN
SECTIONS OF THE FORECAST AREA WHERE SKIES HAD ALREADY CLEARED...WITH
MID AND UPPER 30S ELSEWHERE AT 08Z.
PRIMARY CHALLENGES FOR TODAY FOCUS OVER THE NEXT SIX HOURS THROUGH
MID MORNING WITH RESPECT TO LOW CLOUD COVERAGE AND THE POSSIBILITY
OF FOG DEVELOPMENT AS SKIES CLEAR. MOS AND LAMP GUIDANCE NOT
CAPTURING THE RAPIDITY OF THE CLEARING VERY WELL AND EVEN THE MOST
RECENT RUC DATA SEEMS TO BE FALLING BEHIND A BIT WITH RESPECT TO THE
SOUTHWARD SURGE IN CLEARING SINCE MIDNIGHT. ALREADY AT 08Z CLEARING
LINE IS APPROACHING THE NORTHERN INDY SUBURBS. HOWEVER...BACK EDGE
OF THE STRATOCU NOT PROGRESSING SOUTH AS QUICKLY OVER FAR EASTERN
INDIANA AND WESTERN OHIO. WITH LIGHT NORTHEAST FLOW THROUGH THE
LOWER LEVELS...QUITE PLAUSIBLE THAT THIS MAY SLOW THE DEPARTURE OF
THE STRATOCU ALONG THE I-70 CORRIDOR UNTIL CLOSER TO DAYBREAK. FOR
NOW...WILL MAINTAIN CLOUDS SOUTH OF I-70 THROUGH DAYBREAK WITH CLEAR
SKIES TO THE NORTH. POTENTIAL FOR FOG DEVELOPMENT IS GREATER OVER
NORTHERN COUNTIES WITH THE CLEARING. POSSIBILITY DOES EXIST FOR
THICKER FOG TO IMPACT A FEW LOCATIONS OVER FAR NORTHERN COUNTIES BUT
OVERALL LIGHT NORTHERLY FLOW AND CONTINUED EXPANSION OF DRIER
AIRMASS FROM THE NORTH SHOULD KEEP THICKER FOG CONFINED TO LOCALIZED
AREAS. WILL CARRY PATCHY FOG NORTH OF I-70 INTO MID MORNING AND
ADJUST ACCORDINGLY AS NEEDED. CONTINUING A MENTION OF PATCHY
FREEZING FOG OVER FAR NORTHERN COUNTIES WHERE SURFACE TEMPS LIKELY
TO BOTTOM OUT AT 28-30 DEGREES.
REMAINDER OF THE DAY WILL BE QUIET AS SKIES BECOME SUNNY UNDER
STRONG HIGH PRESSURE RIDGE. MODEL SOUNDINGS SHOW DEEP SUBSIDENCE
TAKING HOLD WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW EXPECTED FOR
THE REST OF THE DAY.
TEMPS...MOS GUIDANCE SUPPORTED BY LOW LEVEL THERMALS AS TEMPS SHOULD
WARM INTO THE MID AND UPPER 40S THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.
MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.
MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.
TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.
THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.
&&
.AVIATION /DISCUSSION FOR THE 05/15Z KIND TAF UPDATE/...
SATELLITE SHOWS EXTENSIVE AREA OF BROKEN STRATUS ALONG AND EAST OF A
EYE-MIE LINE. BUT MUCH OF THIS IS THIN AND IT WILL NOT BE LONG
BEFORE IT STARTS CLEARING OUT. WILL KEEP IFR CEILINGS FOR ANOTHER
HOUR BEFORE RAPIDLY IMPROVING TO VFR AFTER THAT TIME. PREVIOUS
AVIATION DISCUSSION FOLLOWS...
CLOUDS HAVE HELD OVER KIND/KHUF/KBMG...SO THIS SHOULD PREVENT
CONDITIONS FROM DETERIORATING ANY LOWER THAN MVFR CATEGORY
THROUGH DAYBREAK AT THOSE SITES. HOWEVER...THE CLEARING AT KLAF
HAS CAUSED VISIBILITY RESTRICTIONS DUE TO FOG FORMATION.
SO...ANTICIPATE IFR CONDITIONS AT KLAF THROUGH DAYBREAK...BRIEF
MVFR CONDITIONS FROM SUN 14-15Z...AND THEN VFR CONDITIONS BY SUN
15/16Z.
AS SOON AS FOG LIFTS AND CEILINGS INCREASE AROUND MID
MORNING...FLYING CONDITIONS WILL BE GOOD AT ALL TAF SITES THROUGH
THE REMAINDER OF TAF PERIOD WITH VFR CONDITIONS.
WINDS WILL BE NORTHEASTERLY AT 5 TO 10 KTS THROUGH THIS AFTERNOON
AND WILL THEN BECOME WESTERLY LATE TONIGHT AT 3 TO 6 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR INZ021-
028>031-035-038.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/CP
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...TDUD/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
852 AM EST SUN FEB 5 2012
.UPDATE...
NEAR TERM SECTION UPDATED BELOW.
&&
.SYNOPSIS...
CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.
&&
.NEAR TERM /TODAY/...
WITH VISIBILITIES AROUND HALF A MILE OR LESS AT TIMES IN THE
NORTHWEST COUNTIES AND BELOW FREEZING TEMPERATURES ADDED A
FREEZING FOG ADVISORY EARLIER THAT RUNS THROUGH 10 AM FOR THAT
AREA...WITH THE MAIN CONCERNS BEING VISIBILITY RESTRICTIONS FOR
TRAVELERS AS WELL AS SLICK SPOTS DEVELOPING ON UNTREATED
ROADWAYS...ESPECIALLY BRIDGES AND OVERPASSES. ALSO ADDED SOME
CLOUD COVER FOR THE MORNING ACROSS THE CENTRAL AND SOUTH BASED ON
SATELLITE LOOP...BUT THIS SHOULD BE DISSIPATING IN THE 10 AM TO
NOON TIMEFRAME. PREVIOUS DISCUSSION FOLLOWS...
LIGHT PRECIP AND DRIZZLE RAPIDLY DECREASING IN COVERAGE TO THE
SOUTHEAST OF THE INDY METRO EARLY THIS MORNING...AND EXPECT IT TO BE
CLEAR OF THE FORECAST AREA BY 09-10Z. BACK EDGE OF LOWER CLOUDS ALSO
RAPIDLY DROPPING SOUTH AS DRIER AIR SPREADS INTO THE LOWER GREAT
LAKES. TEMPS WERE HOVERING NEAR FREEZING ACROSS FAR NORTHERN
SECTIONS OF THE FORECAST AREA WHERE SKIES HAD ALREADY CLEARED...WITH
MID AND UPPER 30S ELSEWHERE AT 08Z.
PRIMARY CHALLENGES FOR TODAY FOCUS OVER THE NEXT SIX HOURS THROUGH
MID MORNING WITH RESPECT TO LOW CLOUD COVERAGE AND THE POSSIBILITY
OF FOG DEVELOPMENT AS SKIES CLEAR. MOS AND LAMP GUIDANCE NOT
CAPTURING THE RAPIDITY OF THE CLEARING VERY WELL AND EVEN THE MOST
RECENT RUC DATA SEEMS TO BE FALLING BEHIND A BIT WITH RESPECT TO THE
SOUTHWARD SURGE IN CLEARING SINCE MIDNIGHT. ALREADY AT 08Z CLEARING
LINE IS APPROACHING THE NORTHERN INDY SUBURBS. HOWEVER...BACK EDGE
OF THE STRATOCU NOT PROGRESSING SOUTH AS QUICKLY OVER FAR EASTERN
INDIANA AND WESTERN OHIO. WITH LIGHT NORTHEAST FLOW THROUGH THE
LOWER LEVELS...QUITE PLAUSIBLE THAT THIS MAY SLOW THE DEPARTURE OF
THE STRATOCU ALONG THE I-70 CORRIDOR UNTIL CLOSER TO DAYBREAK. FOR
NOW...WILL MAINTAIN CLOUDS SOUTH OF I-70 THROUGH DAYBREAK WITH CLEAR
SKIES TO THE NORTH. POTENTIAL FOR FOG DEVELOPMENT IS GREATER OVER
NORTHERN COUNTIES WITH THE CLEARING. POSSIBILITY DOES EXIST FOR
THICKER FOG TO IMPACT A FEW LOCATIONS OVER FAR NORTHERN COUNTIES BUT
OVERALL LIGHT NORTHERLY FLOW AND CONTINUED EXPANSION OF DRIER
AIRMASS FROM THE NORTH SHOULD KEEP THICKER FOG CONFINED TO LOCALIZED
AREAS. WILL CARRY PATCHY FOG NORTH OF I-70 INTO MID MORNING AND
ADJUST ACCORDINGLY AS NEEDED. CONTINUING A MENTION OF PATCHY
FREEZING FOG OVER FAR NORTHERN COUNTIES WHERE SURFACE TEMPS LIKELY
TO BOTTOM OUT AT 28-30 DEGREES.
REMAINDER OF THE DAY WILL BE QUIET AS SKIES BECOME SUNNY UNDER
STRONG HIGH PRESSURE RIDGE. MODEL SOUNDINGS SHOW DEEP SUBSIDENCE
TAKING HOLD WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW EXPECTED FOR
THE REST OF THE DAY.
TEMPS...MOS GUIDANCE SUPPORTED BY LOW LEVEL THERMALS AS TEMPS SHOULD
WARM INTO THE MID AND UPPER 40S THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.
MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.
MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.
TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.
THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.
&&
.AVIATION /DISCUSSION FOR THE 05/12Z TAF ISSUANCE/...
CLOUDS HAVE HELD OVER KIND/KHUF/KBMG...SO THIS SHOULD PREVENT
CONDITIONS FROM DETERIORATING ANY LOWER THAN MVFR CATEGORY
THROUGH DAYBREAK AT THOSE SITES. HOWEVER...THE CLEARING AT KLAF
HAS CAUSED VISIBILITY RESTRICTIONS DUE TO FOG FORMATION.
SO...ANTICIPATE IFR CONDITIONS AT KLAF THROUGH DAYBREAK...BRIEF
MVFR CONDITIONS FROM SUN 14-15Z...AND THEN VFR CONDITIONS BY SUN
15/16Z.
AS SOON AS FOG LIFTS AND CEILINGS INCREASE AROUND MID
MORNING...FLYING CONDITIONS WILL BE GOOD AT ALL TAF SITES THROUGH
THE REMAINDER OF TAF PERIOD WITH VFR CONDITIONS.
WINDS WILL BE NORTHEASTERLY AT 5 TO 10 KTS THROUGH THIS AFTERNOON
AND WILL THEN BECOME WESTERLY LATE TONIGHT AT 3 TO 6 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY UNTIL 10 AM EST THIS MORNING FOR INZ021-
028>031-035-038.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN/CP
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
642 AM EST SUN FEB 5 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.
&&
.NEAR TERM /TODAY/...
LIGHT PRECIP AND DRIZZLE RAPIDLY DECREASING IN COVERAGE TO THE
SOUTHEAST OF THE INDY METRO EARLY THIS MORNING...AND EXPECT IT TO BE
CLEAR OF THE FORECAST AREA BY 09-10Z. BACK EDGE OF LOWER CLOUDS ALSO
RAPIDLY DROPPING SOUTH AS DRIER AIR SPREADS INTO THE LOWER GREAT
LAKES. TEMPS WERE HOVERING NEAR FREEZING ACROSS FAR NORTHERN
SECTIONS OF THE FORECAST AREA WHERE SKIES HAD ALREADY CLEARED...WITH
MID AND UPPER 30S ELSEWHERE AT 08Z.
PRIMARY CHALLENGES FOR TODAY FOCUS OVER THE NEXT SIX HOURS THROUGH
MID MORNING WITH RESPECT TO LOW CLOUD COVERAGE AND THE POSSIBILITY
OF FOG DEVELOPMENT AS SKIES CLEAR. MOS AND LAMP GUIDANCE NOT
CAPTURING THE RAPIDITY OF THE CLEARING VERY WELL AND EVEN THE MOST
RECENT RUC DATA SEEMS TO BE FALLING BEHIND A BIT WITH RESPECT TO THE
SOUTHWARD SURGE IN CLEARING SINCE MIDNIGHT. ALREADY AT 08Z CLEARING
LINE IS APPROACHING THE NORTHERN INDY SUBURBS. HOWEVER...BACK EDGE
OF THE STRATOCU NOT PROGRESSING SOUTH AS QUICKLY OVER FAR EASTERN
INDIANA AND WESTERN OHIO. WITH LIGHT NORTHEAST FLOW THROUGH THE
LOWER LEVELS...QUITE PLAUSIBLE THAT THIS MAY SLOW THE DEPARTURE OF
THE STRATOCU ALONG THE I-70 CORRIDOR UNTIL CLOSER TO DAYBREAK. FOR
NOW...WILL MAINTAIN CLOUDS SOUTH OF I-70 THROUGH DAYBREAK WITH CLEAR
SKIES TO THE NORTH. POTENTIAL FOR FOG DEVELOPMENT IS GREATER OVER
NORTHERN COUNTIES WITH THE CLEARING. POSSIBILITY DOES EXIST FOR
THICKER FOG TO IMPACT A FEW LOCATIONS OVER FAR NORTHERN COUNTIES BUT
OVERALL LIGHT NORTHERLY FLOW AND CONTINUED EXPANSION OF DRIER
AIRMASS FROM THE NORTH SHOULD KEEP THICKER FOG CONFINED TO LOCALIZED
AREAS. WILL CARRY PATCHY FOG NORTH OF I-70 INTO MID MORNING AND
ADJUST ACCORDINGLY AS NEEDED. CONTINUING A MENTION OF PATCHY
FREEZING FOG OVER FAR NORTHERN COUNTIES WHERE SURFACE TEMPS LIKELY
TO BOTTOM OUT AT 28-30 DEGREES.
REMAINDER OF THE DAY WILL BE QUIET AS SKIES BECOME SUNNY UNDER
STRONG HIGH PRESSURE RIDGE. MODEL SOUNDINGS SHOW DEEP SUBSIDENCE
TAKING HOLD WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW EXPECTED FOR
THE REST OF THE DAY.
TEMPS...MOS GUIDANCE SUPPORTED BY LOW LEVEL THERMALS AS TEMPS SHOULD
WARM INTO THE MID AND UPPER 40S THIS AFTERNOON.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.
MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.
MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.
TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.
THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.
&&
.AVIATION /DISCUSSION FOR THE 05/12Z TAF ISSUANCE/...
CLOUDS HAVE HELD OVER KIND/KHUF/KBMG...SO THIS SHOULD PREVENT
CONDITIONS FROM DETERIORATING ANY LOWER THAN MVFR CATEGORY
THROUGH DAYBREAK AT THOSE SITES. HOWEVER...THE CLEARING AT KLAF
HAS CAUSED VISIBILITY RESTRICTIONS DUE TO FOG FORMATION.
SO...ANTICIPATE IFR CONDITIONS AT KLAF THROUGH DAYBREAK...BRIEF
MVFR CONDITIONS FROM SUN 14-15Z...AND THEN VFR CONDITIONS BY SUN
15/16Z.
AS SOON AS FOG LIFTS AND CEILINGS INCREASE AROUND MID
MORNING...FLYING CONDITIONS WILL BE GOOD AT ALL TAF SITES THROUGH
THE REMAINDER OF TAF PERIOD WITH VFR CONDITIONS.
WINDS WILL BE NORTHEASTERLY AT 5 TO 10 KTS THROUGH THIS AFTERNOON
AND WILL THEN BECOME WESTERLY LATE TONIGHT AT 3 TO 6 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS DES MOINES IA
544 AM CST SUN FEB 5 2012
...UPDATED FOR THE 12Z AVIATION DISCUSSION...
.SHORT TERM /TODAY/...
WIDESPREAD STRATUS FIELD CURRENTLY PUSHING SOUTH THOUGH NORTHERN IA
EARLY THIS MORNING AND REPRESENTS THE FORECAST CHALLENGE OF THE DAY.
THE STRATUS HAS BE SHIFTING SOUTH AT 16 KTS THE PAST FEW HOURS. THIS
WOULD BRING IT TO THE MISSOURI BORDER AROUND 16Z. THE HRRR HAS
INITIALIZED THE CLOUD PROGRESSION WELL AND SUGGESTS THEY WILL STICK
AROUND MOST OF THE DAY. IF ANY EROSION DOES OCCUR...IT WILL BE ON
THE OUTSIDE EDGES AND THIS WOULD LEAVE CENTRAL IA THE LAST TO
DISSIPATE. WITH NEW SNOW PACK OVER THE SOUTH...LIGHT WINDS AND LACK
OF STRONG SUBSIDENCE...FAVOR THE CLOUDY SOLUTION. THE LACK OF SUN
WILL RESULT IN BELOW GUIDANCE HIGHS TODAY. EXPECT SOME FOG EARLY IN
THE PERIOD AND THE POSSIBILITY REMAINS OF LOCALLY DENSE FOG. BEST
POTENTIAL WILL BE SOUTH OF HIGHWAY 30 AS THE HIGHER DEWPOINTS
ASSOCIATED WITH THE STRATUS SETTLES OVER THE NEW SNOW PACK WHERE
CONDITIONS HAVE ALREADY RADIATED.
.LONG TERM /TONIGHT THROUGH SATURDAY/...
OVERALL MID/LONG RANGE REMAINS RELATIVELY QUIET THROUGH THE
PERIOD...WITH MAINLY DRY CONDITIONS. ISSUE TONIGHT INTO
MONDAY...WILL BE IF STRATUS MOVING INTO THE CWA...WILL LINGER INTO
TONIGHT ACROSS THE AREA/BREAKUP/OR POSSIBLY EVEN REDEVELOP.
STRATUS/FOG HAS BEEN QUITE PERSISTENT ACROSS THE AREAS EAST OF THE
SFC HIGH PRES RIDGE SITUATED ACROSS THE CENTRAL DAKOTAS INTO NE/KS
THE PAST FEW DAYS...THEREFORE EXPECT THIS TREND TO CONTINUE TONIGHT.
THEREFORE HAVE INCREASED CLOUD COVER ACROSS THE SOUTHERN CWA
TONIGHT...AND ADDED IN A MENTION OF FOG AS HIGHER MOISTURE AIR
REMAINS IN PLACE OVER NEW SNOWPACK. OTHERWISE AS WINDS BECOME MORE
WESTERLY TO SOUTHWESTERLY AHEAD OF THE NEXT SYSTEM...EXPECT
CLOUDS/FOG TO ERODE ACROSS THE AREA MONDAY. TWO SYSTEMS OF NOTE
MONDAY INTO MONDAY NIGHT...WITH UPPER LEVEL SPLIT FLOW REGIME IN
PLACE. ONE STRENGTHENING UPPER LOW SITUATED ALONG THE FRONT RANGE OF
THE ROCKIES TUESDAY...EXPECTED TO SLIDE EAST INTO TUESDAY. ANOTHER
UPPER LEVEL SHORTWAVE DROPPING SOUTHEASTWARD FROM SASK/ALBERTA
THROUGH THE DAKOTAS/MN. THESE SYSTEMS TO MERGE OVER THE AREA TUESDAY
INTO TUESDAY NIGHT BRINGING INCREASING CLOUDS...AND POSSIBLY A
CHANCE FOR SOME LIGHT SNOW ACROSS THE SOUTHERN CWA. MAJORITY OF
PRECIPITATION EXPECTED TO FALL SOUTH OF IOWA...BUT SOUNDINGS TRY TO
SATURATE A BIT WITH WEAK LIFT ALONG AND SOUTH OF I-80. THEREFORE DID
EXPAND COVERAGE OF SLIGHT CHANCE POPS TO INCLUDE SOUTHERN HALF OF
CWA FOR TUESDAY...WITH THE SYSTEM QUICKLY SLIDING EAST/SOUTHEASTWARD
TUESDAY NIGHT WITH MAYBE SOME LINGERING SNOW ACROSS THE FAR
SOUTHEAST. OTHERWISE CAA EXPECTED THROUGHOUT THE DAY WITH
CLOUDS...SO EXPECT AN EARLY MAX TEMP WITH STEADY OR FALLING TEMPS
THROUGH THE REMAINDER OF THE DAY. HIGH PRESSURE TO BUILD INTO THE
AREA FOR WEDNESDAY...WITH BROAD UPPER LEVEL TROUGHING STILL EXPECTED
TO DIG SOUTHWARD ACROSS THE CENTRAL/EASTERN US FOR LATE IN THE WEEK.
THIS WILL BRING A COLD FROM SWEEPING THROUGH THE CWA
THURSDAY...SENDING H85 TEMPS INTO THE TEENS BELOW ZERO CELSIUS.
HOWEVER CANADIAN/GFS/PREVIOUS EC MUCH MORE AGGRESSIVE WITH THE SURGE
OF COLD AIR PLUNGING IT MUCH FURTHER SOUTH AND ALLOWING THIS ARCTIC
AIRMASS TO REMAIN IN PLACE ACROSS THE CWA FOR THE WEEKEND. LATEST
00Z EC IS MUCH DIFFERENT...KIND OF BRUSHING THE CWA WITH THE ARCTIC
AIRMASS AND THEN QUICKLY MODERATING THE TEMPS WITH WEAK UPPER
RIDGING INTO THE WEEKEND. THEREFORE SOME UNCERTAINTY WITH TEMPS
TOWARD THE END OF THE PERIOD...SO STUCK NEAR THE CONSALL GUIDANCE
GRIDS...WITH SOME TRENDING TOWARD THE COLDER SOLUTION DUE TO BETTER
CONTINUITY IN THE PAST FEW RUNS.
&&
.AVIATION...05/12Z
LIFR STRATUS DECK MOVING THROUGH THE REGION TODAY IS THE AVIATION
CONCERN THROUGH THE PERIOD. EXPECT THE DECK TO GRADUALLY LIFT TO IFR
WITH IMPROVING VSBYS LATE THIS MORNING INTO THE AFTERNOON. VERY
LIKELY THE CIGS WILL MAINTAIN THROUGH THE REMAINDER OF THE DAY
THOUGH SOME EROSION ON THE OUTER EDGES IS POSSIBLE. STEERING FLOW
WILL BECOME MORE WESTERLY OVERNIGHT. THIS WILL HELP DRIVE THE
STRATUS SLOWLY EAST...HOWEVER BY EVENING THE STRATUS MAY BEGIN TO
EXPAND AGAIN WITH CIGS LOWERING BACK TO LIFR ALONG WITH AREAS OF FOG
REDEVELOPING.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE
&&
$$
SHORT TERM...DONAVON
LONG TERM...BEERENDS
AVIATION...DONAVON
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
958 AM EST SUN FEB 05 2012
...10 AM Forecast Update...
Updated the forecast this morning to remove fog wording from the
zones. Also, according to 12Z NAM and 12Z HRRR moisture/CIG
fields...it looks like low clouds may stick around a bit longer than
previously anticipated. The adjustment of clearing to the forecast
was only by an 1 or 2. Satellite trends this morning justify this
thinking. NE sections of our forecast area including Lexington will
be one of the first to see low clouds scatter out. No major temp
adjustments this morning. Highs still look to be limited to the mid
40s to around 50.
7 AM Forecast Update...
Drier air continues to slowly work southward as surface low over the
Carolinas departs to the east and surface trough swings through the
area. Some patches of dense fog and areas of low stratus have
developed this morning, although conditions should gradually improve
through the morning hours as the sun comes up and drier air
continues to work in. Issued a Special Weather Statement across
central Kentucky for the patches of dense fog through 9 AM EST. A
few patches of drizzle will also exist through midday, along with
the small chance that a light rain shower could measure. Otherwise,
temperatures will struggle today under northeasterly flow and slow
to clear clouds. Look for highs in the mid and upper 40s, but would
not be surprised to only see the mercury make it to the mid 40s.
&&
.Short Term (Today and Tonight)...
Surface low has moved east of the Appalachian spine to the North
Carolina/Virginia border. Meanwhile, upper low continues to spin
over the Kansas City region. Low clouds and patches of drizzle
remain over the area, along with patches of fog. Have left mention
of a slight chance of a measurable rain shower in the grids early
this morning, however think most locations will only see drizzle.
Temperatures will continue to drop into the upper 30s and low 40s
north of the parkways. Mid and upper 40s are expected across south
central Kentucky as winds have not shifted to northeasterly on the
warm side of a surface trough.
As we move through the daylight hours, surface low will move off the
Carolina Coast with upper low transitioning to an open wave. Expect
low clouds and slight chances of a measurable rain shower or drizzle
ahead of the nearly East/West oriented upper trough axis that
develops along the Ohio River to the eastern Plains. This axis will
gradually sink south along with deepest low level moisture, ending
chances of precipitation from north to south through the day. Skies
will also begin to clear out in the afternoon along and north of the
I 64 corridor. High temperatures are expected to struggle with cloud
cover for a good portion of the day along with northeasterly surface
flow. Look for highs mainly in the middle to upper 40s.
As we move into tonight, skies should be mostly clear as drier air
works into the region on continued northerly flow. Surface high will
be in control along with upper level ridging over the northern CWA.
Have patchy fog developing mostly in the sheltered valleys and in
southwestern Indiana under the upper level ridge. Think drier
airmass will keep fog from becoming more widespread, however will
have to monitor. Lows should dip into the lower 30s in most spots
with a few of the cool spots into the upper 20s.
.Long Term (Monday - Saturday)...
Slow-moving upper low in the short term will pick up steam toward
the east and clear the region during the day Monday. High pressure
building into the area will mean dry conditions at least through
Tuesday. Then from midweek on a series of upper level disturbances
will set up a large-scale trough over the Eastern U.S., bringing in
a more winter like cool down. None of the systems look overly wet
among the various long-term models. As the large-scale trough
becomes better established later in the day Friday, we may see a
band of precip come across, as per the latest GEM and GFS solutions.
GFS sounding indicates most of the layer will be below freezing,
except for a warmer surface. Previous forecast kept best chance,
only slight, in for Wednesday, then dry through the end of the
period. Will trim pops a little Wednesday and bump them up a little
Friday and Friday night, to slight chance over the east and
southeast, in line with the AllBlend. Both sets of periods will keep
as a rain/snow mix given forecast soundings and surface temperature
forecasts.
Speaking of temperatures, have readings starting off around 50 for
highs Monday, going up a few degrees over the south Tuesday, then
should be in the 40s all locations Wednesday and Thursday. The
cooler air will filter in Friday, with highs in the 30s over the
north. Then Saturday, all but south central Kentucky should remain
in the 30s for highs. Saturday morning should be the coolest all
locations, with lows in the 20s.
&&
.Aviation (12Z TAF Issuance)...
Low pressure over the Carolinas will move off the coast today.
Meanwhile, an upper level disturbance will remain just to our north
and west. Low ceilings, drizzle, and an occasional light rain shower
will be possible through at least midday before conditions begin to
clear from north to south as drier air works in. Have IFR ceilings
persisting at SDF/LEX until around Noon EST before ceilings
gradually scatter out through the afternoon. Expect generally north
northeast winds between 5 and 10 mph through the day.
BWG is a lower confidence forecast. Expect ceiling in the IFR range
early this morning to give way to mostly low MVFR ceilings by mid
morning. Thereafter, expect mostly low MVFR through the remainder of
the day, although could see a few brief periods of IFR before low
level moisture exits to the south this evening.
With clear skies and calming winds expected later tonight, fog may
become a concern at the TAF sites toward dawn. Will nail this down
with later issuances.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS/BJS
Short Term.......BJS
Long Term........RJS
Aviation.........BJS
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
627 AM EST SUN FEB 5 2012
.SYNOPSIS...
ANY REMAINING MIX OF LIGHT RAIN AND SNOW ACROSS THE MOUNTAINS WILL
END THIS MORNING, AS UPPER LEVEL DISTURBANCE EXITS EAST. HIGH
PRESSURE, COMING EAST FROM THE PLAINS, WILL THEN FOLLOW TO BRING SUNSHINE
BY AFTERNOON, AND AGAIN ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT RADAR DATA TRENDS AND HRRR AND WRF-NMM MODEL OUTPUT
CONTINUE TO SHOW ANY LIGHT MIX OF RAIN AND WET SNOW ACROSS THE
SOUTH EAST RIDGES WILL END BEFORE MID-MORNING, AS AN UPPER LEVEL
JETSTREAM MAX EXITS EAST. THERE MAY BE A SMALL ACCUMULATION OF WET
SNOW OVER THE HIGHER MOUNTAINS.
RECENT SURFACE DATA SHOWS SIGNS THAT THE LOW CLOUDS RESULTING IN
FOG PATCHES OVER THE HIGHER PA-WV-MD MOUNTAINS, HAS BEGUN TO LIFT. SO
EXPECT ANY REMAINING HIGHER ELEVATION FOG TO HAVE ENDED BY 9 AM.
PER TRENDS IN RECENT SATELLITE DATA AND SUPPORT FROM RECENT HRRR
AND NAM MODEL OUTPUT, EXPECT CLOUDS TO ALSO DECREASE, NORTH TO
SOUTH, THIS MORNING, YIELDING A DECENT AMOUNT OF SUNSHINE BY AFTERNOON.
HAVE CONTINUED TO FINE TUNE TEMPERATURE FORECAST PER RECENT HRRR
AND GFS LAMP MODEL OUTPUT. EXPECT AFTERNOON HIGHS TO BE 2 TO 5
DEGREES WARMER THAN NORMAL, WHICH IS ALSO SUPPORTED BY RECENT NAM
AND GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
BLEND OF RECENT SREF AND ECMWF MODEL OUTPUT SHOWS SPRAWLING HIGH
PRESSURE, EXTENDING FROM THE PLAINS TO THE APPALACHIANS, WILL
PROVIDE NO MORE THAN SCATTERED CLOUDS ACROSS THE UPPER OHIO VALLEY
TONIGHT INTO TUESDAY. THIS WILL MAINTAIN MILD CONDITIONS, WITH
LOWS AND HIGHS GENERALLY 5 TO 8 DEGREES WARMER THAN NORMAL.
MODELS THEN SHOW STRONG HIGH PRESSURE SPREADING SOUTHEASTWARD FROM
THE CANADIAN PLAINS. THIS WILL PUSH A COLD FRONT SOUTHWARD THROUGH
THE UPPER OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE FRONT MAY
HAVE LITTLE MOISTURE TO INGEST, SO MAINTAINED A SLIGHT CHANCE OF
PREFRONTAL SHOWERS TUESDAY NIGHT, AND A CHANCE OF POSTFRONTAL SHOWERS
WEDNESDAY.
THE PRECIPITATION TYPE WILL BE A MIX OF RAIN AND SNOW, AS SURFACE
LAYER TEMPERATURES WILL STRADDLE THE FREEZING POINT. THIS IDEA IS
SUPPORTED BY RECENT GFS AND NAM MOS WHICH SHOW TEMPERATURES TO
LOWER TO SEASONABLE LEVELS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A DEEP UPPER
LOW PASSING EASTWARD THROUGH EASTERN CANADA LATE WEEK. HENCE
EXPECT A COLD FRONT, WITH A MIX OF RAIN AND SNOW SHOWERS, TO PASS
THROUGH THE UPPER OHIO VALLEY AROUND FRIDAY. FOR NOW HAVE
CONTINUED FORECAST OF NEAR-SEASONABLE POSTFRONTAL TEMPERATURES FOR
SATURDAY. HOWEVER, RECENT NAEFS MEDIAN VALUES AND GFS MOS SUGGEST
TEMPERATURES SATURDAY COULD BECOME 5 TO 10 DEGREES COLDER THAN
NORMAL.
&&
.AVIATION /11Z SUNDAY THROUGH THURSDAY/...
DRY AIR WORKING IN FROM THE NORTH IS PROHIBITING MUCH FOG OR
STRATUS DEVELOPMENT EARLY THIS MORNING EXCEPT FOR KMGW AND THE
MOUNTAINS EAST. ANY PATCHY MVFR FOG WILL QUICKLY BURN OFF AFTER
SUNRISE. AS UPPER TROUGH EXITS EAST THIS MORNING FOG AND STRATUS
FROM MGW AND RIDGES WILL LIFT WITH REMAINING MID DECK QUICKLY
SHIFTING EAST. WINDS WILL BE LIGHT NORTHERLY INTO THE AFTERNOON.
OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
GENERAL VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY. A SERIES OF
SHORT WAVES MAY BRING RESTRICTIONS AT TIMES IN SNOW SHOWERS
WEDNESDAY INTO THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
544 AM EST SUN FEB 5 2012
.SYNOPSIS...
ANY REMAINING MIX OF LIGHT RAIN AND SNOW ACROSS THE MOUNTAINS WILL
END THIS MORNING, AS UPPER LEVEL DISTURBANCE EXITS EAST. HIGH
PRESSURE, COMING EAST FROM THE PLAINS, WILL THEN FOLLOW TO BRING SUNHINE
BY AFTERNOON, AND AGAIN ON MONDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
RECENT RADAR DATA TRENDS AND HRRR AND WRF-NMM MODEL OUTPUT
CONTINUE TO SHOW ANY LIGHT MIX OF RAIN AND WET SNOW WILL END
BEFORE MID-MORNING, AS AN UPPER LEVEL JETSTREAM MAX EXITS EAST.
THERE MAY BE A SMALL ACCUMULATION OF WET SNOW OVER THE HIGHER
MOUNTAINS.
RECENT SURFACE DATA SHOWS SIGNS THAT THE LOW CLOUDS RESULTING IN
FOG PATCHES OVER THE HIGHER PA-WV-MD MOUNTAINS, HAS BEGUN TO LIFT. SO
EXPECT ANY REMAINING HIGHER ELEVATION FOG TO HAVE ENDED BY 9 AM.
PER TRENDS IN RECENT SATELLITE DATA AND SUPPORT FROM RECENT HRRR
AND NAM MODEL OUTPUT, EXPECT CLOUDS TO ALSO DECREASE, NORTH TO
SOUTH, THIS MORNING, YIELDING A DECENT AMOUNT OF SUNSHINE BY AFTERNOON.
HAVE CONTINUED TO FINE TUNE TEMPERATURE FORECAST PER RECENT HRRR
AND GFS LAMP MODEL OUTPUT. EXPECT AFTERNOON HIGHS TO BE 2 TO 5
DEGREES WARMER THAN NORMAL, WHICH IS ALSO SUPPORTED BY RECENT NAM
AND GFS MOS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
BLEND OF RECENT SREF AND ECMWF MODEL OUTPUT SHOWS SPRAWLING HIGH
PRESSURE, EXTENDING FROM THE PLAINS TO THE APPALACHIANS, WILL
PROVIDE NO MORE THAN SCATTERED CLOUDS ACROSS THE UPPER OHIO VALLEY
TONIGHT INTO TUESDAY. THIS WILL MAINTAIN MILD CONDITIONS, WITH
LOWS AND HIGHS GENERALLY 5 TO 8 DEGREES WARMER THAN NORMAL.
MODELS THEN SHOW STRONG HIGH PRESSURE SPREADING SOUTHEASTWARD FROM
THE CANADIAN PLAINS. THIS WILL PUSH A COLD FRONT SOUTHWARD THROUGH
THE UPPER OHIO VALLEY TUESDAY NIGHT INTO WEDNESDAY. THE FRONT MAY
HAVE LITTLE MOISTURE TO INGEST, SO MAINTAINED A SLIGHT CHANCE OF
PREFRONTAL SHOWERS TUESDAY NIGHT, AND A CHANCE OF POSTFRONTAL SHOWERS
WEDNESDAY.
THE PRECIPITATION TYPE WILL BE A MIX OF RAIN AND SNOW, AS SURFACE
LAYER TEMPERATURES WILL STRADDLE THE FREEZING POINT. THIS IDEA IS
SUPPORTED BY RECENT GFS AND NAM MOS WHICH SHOW TEMPERATURES TO
LOWER TO SEASONABLE LEVELS.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
BLEND OF RECENT ECMWF AND NAEFS MODEL OUTPUT SHOWS A DEEP UPPER
LOW PASSING EASTWARD THROUGH EASTERN CANADA LATE WEEK. HENCE
EXPECT A COLD FRONT, WITH A MIX OF RAIN AND SNOW SHOWERS, TO PASS
THROUGH THE UPPER OHIO VALLEY AROUND FRIDAY. FOR NOW HAVE
CONTINUED FORECAST OF NEAR-SEASONABLE POSTFRONTAL TEMPERATURES FOR
SATURDAY. HOWEVER, RECENT NAEFS MEDIAN VALUES AND GFS MOS SUGGEST
TEMPERATURES SATURDAY COULD BECOME 5 TO 10 DEGREES COLDER THAN
NORMAL.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
IFR CONDITIONS IN FOG AND STRATUS MAY REMAIN ACROSS KMGW AND THE
MOUNTAINS EAST INTO MID MORNING, AS LOW LEVEL MOISTURE FROM
PREVIOUS LIGHT MIXED PRECIPITATION WILL BE TRAPPED UNTIL SURFACE
HIGH CAN MIX BOUNDARY LAYER.
FARTHER NORTH, ACROSS THE KZZV-KPIT-KLBE CORRIDOR, HAVE LOWERING
CONFIDENCE THAT CURRENT MVFR VISIBILITY RESTRICTIONS BY FOG WILL
DETERIORATE TO IFR THIS MORNING. IF STRATUS FAILS TO DEVELOP,
VISIBILITIES WILL IMPROVE TO VFR BY LATE MORNING.
NORTHERN TERMINALS, KFKL AND KDUJ, WILL STAY VFR THROUGH PERIOD. WINDS
WILL BE LIGHT NORTHERLY INTO THE AFTERNOON.
OUTLOOK...SUNDAY NIGHT THROUGH THURSDAY...
GENERAL VFR CONDITIONS ARE EXPECTED THROUGH TUESDAY. A SERIES OF
SHORT WAVES MAY BRING RESTRICTIONS AT TIMES IN SNOW SHOWERS
WEDNESDAY INTO THURSDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
554 AM CST SUN FEB 5 2012
.UPDATE...
.AVIATION.../12Z TAF ISSUANCE/
IFR CIGS AFFECTING EASTERN MN WITH LIFR TO VLIFR CONDITIONS
AFFECTING WESTERN SITES. WEST CENTRAL WI HAS BEEN SKC OVERNIGHT
BUT SOME IFR CIGS TO BE MOVING INTO KRNH SHORTLY. KEAU MAY REMAIN
SKC-SCT CLOUDY BUT SOME MVFR VSBYS POSSIBLE. THE CURRENT
CONDITIONS MAY REMAIN IN PLACE UNTIL 16Z WITH SOME LIFTING OR
BREAKING BETWEEN 16Z AND 18Z. NW TO WEST WIND WITH THE HIGH
PUSHING IN SHOULD PROMOTE CLEARING SIMILAR TO YESTERDAY. AN
OVERALL DRIER ATMOSPHERE SHOULD YIELD MOSTLY CLEAR CONDITIONS
OVERNIGHT. WILL NEED TO WATCH TRENDS LATER THIS AFTERNOON FOR
MINOR FOG DEVELOPMENT LATER TONIGHT. CURRENT THINKING IS A LOW
RISK AND IT WOULD BE MVFR VSBYS. GENERAL NW WIND THIS MORNING
BECOMING WEST THIS AFTERNOON...WSW TONIGHT...ALL LESS THAN 10
KNOTS.
KMSP...CIGS JUST INTO IFR CATEGORY THIS MORNING BUT VSBYS SHOULD
BE MVFR IF THEY DO GO DOWN. EXPECT THE CIGS TO REMAIN UNTIL ABOUT
17Z WITH CLEARING DEVELOPING 18Z-19Z. GENERALLY SKC CONDITIONS
AFTER 21Z BUT WILL NEED TO WATCH FOR THE POSSIBILITY OF MVFR VSBYS
IN FOG LATE TONIGHT. NOT AS LIKELY AS THE LAST FEW NIGHTS.
.MONDAY...VFR
.MONDAY NIGHT AND TUESDAY...MVFR CIGS POSSIBLE WITH THE ARRIVAL OF
A COLD FRONT.
&&
.DISCUSSION...
THE FORECAST CONCERN IN THE NEAR TERM REMAINS THE STRATUS OVER THE
REGION ONCE AGAIN THIS MORNING. SOUTHEAST MOVEMENT OF CLOUD DECK
SHOULD ENVELOP ALL OF MINNESOTA PORTION OF THE REGION. HRRR TRENDS
INDICATE NORTHEAST WISCONSIN CLOUDS TO WORK SOUTHWEST INTO THAT
REGION DURING THE MORNING. VSBYS NOT ALL THAT BAD THIS AM...WITH
MOST AREAS ABOVE 2SM. DOES APPEAR MORE WEST/SOUTHWEST FLOW
DEVELOPING AHEAD OF NEXT COLD FRONT SHOULD BE ENOUGH TO MIX OUT
THE STRATUS OVER THE NORTHWEST PORTION OF THE AREA THIS AFTERNOON.
WILL MENTION PARTLY CLOUDY DEVELOPING IN THE SOUTHEAST...AS
CONFIDENCE NOT HIGH ON STRATUS TOTALLY CLEARING OUT. SHOULD SEE
TEMPERATURES WARM THROUGH THE 30S INTO THE 40S WHERE CLOUDS CLEAR
FASTEST TODAY.
COLD FRONT DROPS INTO NORTHERN MINNESOTA OVERNIGHT TONIGHT. WITH
SOUTHWEST FLOW DEVELOPING SHOULD SEE TEMPERATURES STAY UP A BIT
OVERNIGHT. COULD SEE A TOUCH OF FOG OVER WESTERN WI THIS
EVENING...BUT WILL LIKELY IMPROVE AFTER MIDNIGHT IF IT DOES
DEVELOP...AS FRONT/PRESSURE GRADIENT SAGS INTO THE AREA. TEMPERATURES
SHOULD START OUT RATHER WARM MONDAY AND SHOULD SEE SOME UPPER 40S
AGAIN IN THE FAR SOUTH BEFORE FROPA IN THE AFTERNOON. CLOUDS MAY
HOLD OFF UNTIL EVENING OVER MUCH OF THE AREA...BUT DO EXPECT THEM
AROUND MUCH OF MONDAY NIGHT. MAY EVEN SEE A FLURRY OR TWO.
FLOW PATTERN APPEARS TO BE IN TRANSITION AGAIN AS WESTERN BLOCK
REMAINS. GFS AND GEM TREND AM AMPLIFICATION OF THE EASTERN CONUS
TROUGH WITH THE GFS THE MOST AMPLIFIED/COLDEST. THE 00Z ECMWF
CONTINUES ITS TREND OF DIVING SOME TROUGH ENERGY SOUTH OVER THE
EASTERN CONUS THROUGH THE WEEK BUT THE WESTERN BLOCK IS ERODED
WEST LATE IN THE WEEK WITH A MORE ZONAL TYPE FLOW PATTERN
DEVELOPING INTO THE HE WEEKEND. EXTENDED DISCUSSION DID MENTION
THEY DID NOT LIKE THE ECMWF TREND...AND THEY HELD ONTO THE EASTERN
CONUS TROUGH A BIT LONGER. THIS DOES SPELL COLDER THAN NORMAL FOR
LATE IN THE WEEK. AT THE MOMENT...PERIOD IS DRY...BUT THERE MAY BE
A FEW SNOW SHOWERS/FLURRIES...MAINLY EAST...AS COLDEST AIR
ARRIVES THURSDAY INTO FRIDAY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/JPR
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
607 AM CST SUN FEB 5 2012
.DISCUSSION...
/255 AM CST SUN FEB 5 2012/
THE SHORT TERM FORECAST OVER THE NEXT 12 HOURS POSES THE BIGGEST
CHALLENGES OVER THE NEXT SEVERAL DAYS. THE FEATURE OF CONCERN IS
THE UPPER LOW FORECAST TO DROP SEWD THROUGH THE AREA TODAY AND THE
ASSOCIATED IMPACTS. PROFILER AND VWP DATA SHOW THAT THE UPPER LOW
HAS PASSED JUST SE OF KANSAS CITY. THE VAST MAJORITY OF PRECIPITATION
THUS FAR HAS ACTUALLY BEEN TO THE NORTH OF THE LOW CENTER...AND
HAS BEEN ROTATING SOUTHWESTWARD ABOUT THE CIRCULATION. NEAR AND
NORTH OF THE LOW ARE THE ONLY LOCATIONS THAT HAVE REPORTED ANY
SNOW THUS FAR AS WELL. CURRENTLY TO THE EAST OF THE LOW ACROSS
EASTERN MO...BANDS OF RAIN SHOWERS HAVE DEVELOPED WITHIN THE LAST
FEW HOURS WITHIN WHAT APPEARS TO BE A REGION OF MID LEVEL QG
FORCING. TEMPERATURES WITHIN THIS AREA RANGE FROM THE UPPER 30S TO
LOWER 40S. THE RUC APPEARS TO HAVE THE BEST HANDLE ON THE TRACK OF
THE UPPER LOW AT THIS TIME...TRACKING IT TO NEAR THE LAKE OF THE
OZARKS REGION BY 18Z. THEREAFTER THE MAJORITY OF THE MODELS WOULD
SUGGEST IT WILL CONTINUE TO TRACK SEWD AND INTO SE MO THIS
AFTERNOON AND THEN EXIT INTO THE WESTERN TN VALLEY TONIGHT. BASED
ON THIS LOW TRACK AND THE ASSOCIATED QG FORCING TO THE EAST...EXPECTING
CHANCE POPS/SCATTERED SHOWERS/DRIZZLE TO IMPACT THE AREA FROM
COU-STL-SLO SOUTHWARD. I AM NOT VERY EXCITED ABOUT THE PROSPECTS
OF ANY SNOW AND GIVEN ONLY SLIGHTLY COOLER TEMPERATURES EARLY THIS
MORNING THAN NOW...I WOULDN`T EXPECT ANY ACCUMULATION IF WE DID
SEE SOME. BY THIS AFTERNOON THE POP THREAT SHOULD BE CONFINED TO
FAR SE MO. STRATUS WILL SLOWLY CLEAR SOUTH THROUGH THE DAY AS
WELL.
WEAK HIGH PRESSURE WILL DOMINATE THE REGION TONIGHT WITH
SEASONABLY CHILLY TEMPERATURES. WESTERLY LOW LEVEL FLOW AND WARM
ADVECTION THEN GETS GOING ON MONDAY AND TEMPERATURES WILL ONCE
AGAIN BE ABOVE AVERAGE. THE NEXT SHOT OF COLD AIR LOOKS ON TRACK
FOR TUESDAY AS A NORTHERN STREAM SHORT WAVE TROF DIGS SOUTHEAST
INTO THE UPPER MIDWEST AND INTERACTS WITH THE REMNANT GREAT BASIN
UPPER LOW. WE CURRENTLY HAVE POPS JUST BELOW THRESHOLDS THAT ARE
MENTIONED IN THE FORECAST FOR THIS SYSTEM. THERE IS AND HAS BEEN
QUITE A BIT OF VARIABILITY WITH THE PRECIPITATION CHANCES...AND
CONFIDENCE IS LOW AT THIS TIME. ANYWAY THIS SHOT OF COLD AIR WILL BE A
GLANCING SHORT-LIVED BLOW BRINGING TEMPERATURES BACK DOWN TO
SEASONABLE NORMS TUESDAY NIGHT-WED NIGHT.
THE LONGER RANGE GUIDANCE...WHILE SHOWING SOME DETAIL DIFFERENCES
...IS TRENDING TOWARDS TEMPERATURES MORE WINTER-LIKE BY THE END
OF THE UPCOMING WEEK. THE GENERAL IDEA AT THIS JUNCTURE IS A DEEP
VORTEX WILL BECOME ESTABLISHED NEAR HUDSON BAY WITH A DEEP FULL
LATITUDE TROF EXTENDING TO THE SOUTH INTO THE EASTERN U.S.. THE
ORIENTATION OF THIS TROF AND INTENSITY/LONGEVITY OF THE COLD AIR
ARE WHERE THE MODELS DIFFER WITH THE GFS SHOWING POTENTIAL FOR
SOME OF THE COLDEST AIR THIS SEASON.
GLASS
&&
.AVIATION...
/541 AM CST SUN FEB 5 2012/
IFR FLIGHT CONDITIONS IN LOW CLOUDS...DRIZZLE AND FOG WILL
CONTINUE TO PREVAIL ACROSS THE BI-STATE REGION THROUGH MUCH OF THE
MORNING HOURS ALONG AND SOUTH OF A LINE FROM KTAZ TO KMYJ. WILL SEE
CONDITIONS IMPROVE AS DRIER LOW LEVEL AIR WORKS SOUTH-SOUTHWEST
ACROSS THE AREA THROUGH MID-LATE MORNING. COULD STILL SEE SOME
LIGHT SNOW ACROSS PARTS OF CENTRAL MISSOURI EARLY THIS
MORNING...BUT THINK CHANCE IS TOO LOW TO MENTION IN KCOU TAF. LOW
CLOUDS WILL FINALLY CLEAR OUT OF SOUTHEAST MISSOURI LATE THIS
AFTERNOON OR EARLY SUNDAY EVENING. NEXT POTENTIAL IMPACT WILL BE
FOG LATE TONIGHT AND EARLY MONDAY MORNING. THINK GREATEST
POTENTIAL FOR FOG WILL BE ALONG AND SOUTH OF THE I-70 CORRIDOR
WHERE THE MOST RAIN HAS FALLEN OVER THE PAST 2 DAYS AND WHERE
CLOUDS WILL PERSIST THE LONGEST TODAY. UNSURE THOUGH AS TO AREAL
COVERAGE AND INTENSITY OF THE FOG AT THIS TIME.
SPECIFICS FOR KSTL...
IFR FLIGHT CONDITIONS WILL PERSIST FOR A GOOD PORTION OF THE
MORNING...AS WELL AS OCCASIONAL DRIZZLE AND/OR LIGHT RAIN. UNSURE
WHEN CONDITIONS WILL IMPROVE...BUT GUIDANCE SUGGESTS THE LOW
CLOUDS SHOULD MOVE SOUTH OF THE TERMINAL DURING THE MID-LATE
MORNING AS DRIER AIR WORKS ITS WAY INTO EAST CENTRAL MISSOURI.
ONCE THE LOW CLOUDS MOVE SOUTH OF LAMBERT VFR FLIGHT CONDITIONS
ARE EXPECTED AT LEAST THROUGH 06Z TONIGHT. AM EXPECTING FOG TO
DEVELOP LATE TONIGHT...BUT TIMING AND INTENSITY ARE UNCERTAIN AT
THIS TIME.
CARNEY
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
538 AM CST Sun Feb 5 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today - Tonight:
The upper low that has affected the region over the last few days
continues to weaken as it spins over northwestern Missouri. Warming
cloud top temperatures per IR satellite, decreasing radar returns and
increasing ceilings and visibilities all confirm the weakening of the
system. This trend will continue as the low slides southeast into
central Missouri and any remaining precipitation will be confined to
the vicinity of the low so have added low pops through our
southeastern zones to account for this. Any precipitation should be
out of the forecast area by mid to late morning so have kept the
afternoon period dry.
Outside of the lingering precipitation chances, today`s cloud
forecast is rather difficult. The clouds associated with the upper
low should move south and east/erode through the day. But 11-3.9u
satellite imagery reveals an area of very low stratus and fog moving
southward through Iowa and Nebraska. There may be a period of time
this morning when northern Missouri clears completely out and
coupled with recent snow across the far northwest corner of the
state could have dramatic effects on our temperatures due to
radiational cooling around sunrise. I am not overly confident on the
timing of either cloud element in our north so have tended to play
the middle ground with regards to temperatures there. Models have
very poor handling of the low stratus but see no reason why it won`t
progress southward into northern Missouri by mid morning or so,
further limiting any warm up in that part of the forecast area.
For tonight, while quiet weather is expected, models continue to
struggle with the effects of the new snow cover to our north and
northwest. The latest SREF visibility and ceiling probability
forecast indicate an increasing potential for low clouds and lower
visibilities across our north. Have therefore added a mention of fog
across northern Missouri as this makes conceptual sense given the
moist and cool boundary layer.
Monday:
Quiet weather is expected for this period as the upper level energy
that brought the region snow has been split apart, with one piece
heading east and another that has gotten cutoff within the upper
ridge over western North America. Mostly clear/clear skies are
expected and we should be able to warm back into the mid to upper 40s
for most locations and even a few 50 degree readings are possible in
our southern zones.
Monday Night - Tuesday:
The above mentioned cutoff portion should begin to eject eastward
through the Central Plains, aided by another wave diving southward
out of Canada. This will bring a chance for precipitation across the
forecast area by mid day Tuesday and with a very strong, 1040mb high
pressure surging down the Plains behind the Canadian system, enough
cold air will be move into the region bring a chance for light snow
to the forecast area. The GFS seems to the most robust with this
system with other models offering up a weaker system with less QPF.
So this system will need to be watched for the potential for light
accumulating snow. Temperatures Tuesday may not budge much from
overnight lows, especially across northern Missouri, given the cloud
cover and warm advection and highs in the lower 30s are expected
across that part of the forecast area.
Wednesday - Sunday:
Dry weather is expected to prevail through the extended period. With
a ridge developing over the western CONUS and deep troughing over
the east persisting into the later half of the week, we should see
northwesterly flow across the Central Plains. This should keep us
close to or just above normal for most the period with the possible
exception of Friday, when a colder airmass moves into the eastern
Plains/Midwest in response to the deepening eastern trough. There is
quite a bit of spread amongst the models, both deterministic and
ensembles, with how deep the trough digs but by the end of the
weekend, flow should become less amplified and a return to above
normal temperatures is expected.
CDB
&&
.AVIATION...
Precipitation has ended across all terminals early this morning with
only lingering BKN mid level cloud cover across the area. Clouds should
continue to break up through the next few hours and winds will remain
light through the day. Uncertainty arises thereafter as short range
guidance struggles to handle the ongoing LIFR (occasional VLIFR) cigs
and fog advecting southward across Iowa this morning. A combination
of the SREF and HRRR seem to be handling this the best at the moment
and bring the stratus/fog near the Missouri/Iowa border before
halting its southern progress. Therefore, will not bring this cloud
deck into KSTJ later this morning and will continue to indicate VFR
conditions this afternoon. However, SREF does indicate this cloud
deck/fog area to once again expand southward tonight, moving into
northern Missouri. Still much uncertainty as to whether this will
affect the terminals tonight. Will bring the edge of the stratus and
some moderate fog into KSTJ to account but will keep it north of the
Kansas City terminals for now. There is certainly some possibility of
IFR or LIFR cigs/vis overnight at STJ but confidence is not high
enough to include in the TAF at the moment.
Deroche
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS HASTINGS NE
513 AM CST SUN FEB 5 2012
.AVIATION...12Z KGRI TAF. VFR CEILING/VISIBILITY ARE CURRENTLY
ADVERTISED THROUGHOUT THE PERIOD...WITH LIGHT WEST-NORTHWEST
BREEZES ONLY AVERAGING AROUND 7KT OR SO. THAT BEING SAID...AT
THIS HOUR...A FAIRLY EXTENSIVE IFR/LIFR STRATUS DECK ALSO
FEATURING IFR/LIFR VISIBILITY IS LURKING ROUGHLY 120 MILES
NORTH-NORTHEAST OF KGRI...AND IS SHOWING SOME SIGNS OF SAGGING
SOUTH TOWARD THE AREA OVER THE NEXT SEVERAL HOURS WITHIN THE LOW
LEVEL NORTHERLY STEERING FLOW. ALTHOUGH MOST OF THE TRADITIONAL
NUMERICAL GUIDANCE/MODELS ARE STRUGGLING TO CAPTURE THIS STRATUS
SHIELD...THE HIGH RESOLUTION RUC SEEMS TO HAVE THE BEST
HANDLE...AND AT LEAST FOR NOW...SUGGESTS THAT THE SOUTHWEST EDGE
OF THESE CLOUDS SHOULD STALL OUT WITHIN ROUGHLY 50 MILES NORTHEAST
OF KGRI. WILL PLAY THIS OPTIMISTIC SCENARIO FOR NOW...BUT AT
LEAST HINT AT LOW CLOUD POTENTIAL WITH A SCATTERED MENTION THROUGH
THE ENTIRE PERIOD. AS FOR VISIBILITY TRENDS...ASSUMING THAT
STRATUS/FOG STAYS NORTH/EAST OF THE AREA TODAY...ATTENTION TURNS
TO AT LEAST LIGHT FOG POTENTIAL OVERNIGHT WITH VERY SHALLOW MOIST
LAYER FROM MELTING SNOW...ALTHOUGH LIGHT WESTERLY WINDS SHOULD ACT
AGAINST MAJOR FOG ISSUES. FOR NOW THOUGH...WILL MAINTAIN A LIGHT
VFR VISIBILITY RESTRICTION POST-03Z...AND CONTINUE TO EMPHASIZE
THAT THIS FORECAST PERIOD CONTAINS A FEW CAVEATS THAT COULD PUT
VFR CONDITIONS IN JEOPARDY.
&&
.PREV DISCUSSION... /ISSUED 235 AM CST SUN FEB 5 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. 11-3.9 MICRON
SATELLITE IMAGERY EARLY THIS MORNING SHOWED A LARGE AREA OF
STRATUS DROPPING SOUTH FROM EASTERN SOUTH DAKOTA AND MINNESOTA
INTO EASTERN NEBRASKA. THE MODELS OVERALL HAVE NOT DONE A GOOD JOB
IN CAPTURING THIS AREA...THOUGH THE HRRR DOES SEEM TO HAVE AN IDEA
OF ITS PRESENCE. FOLLOWING THE HRRR WOULD SUGGEST THE WESTERN EDGE
OF THE STRATUS COULD MAKE A RUN FOR FAR EASTERN PORTIONS OF THE
FORECAST AREA. WILL INCREASE CLOUDS ACCORDINGLY...BUT IT WILL BE A
SHARPLY DEFINED LINE BETWEEN CLOUDS VS. SUN.
THE NEXT ISSUE WILL BE TEMPERATURES...AND THE MAIN MESSAGE IN THE
FORECAST THE NEXT COUPLE OF DAYS WILL BE TO CUT GUIDANCE
VALUES...ESPECIALLY IN THE HEART OF THE DEEPER SNOWPACK. AM NOT
OVERLY CONFIDENT ABOUT HOW FAR BELOW GUIDANCE TO GO...AND WILL STAY
FAIRLY CLOSE TO THE GOING FORECAST WHICH IS ABOUT 5 TO 10 DEGREES
BELOW BOTH MET AND MAV HIGH TEMPERATURE FORECASTS.
DEBATED ADDING AT LEAST SOME PATCHY FOG TO THE FORECAST TONIGHT WITH
THE 05.00Z NAM SHOWING REDUCED VISIBILITIES OVERNIGHT INTO MONDAY
MORNING. THE MAIN THING THAT KEPT US FROM JUMPING ON IT AT THIS
POINT IS THAT BOUNDARY LAYER RELATIVE HUMIDITY VALUES ARE NOT VERY
HIGH OVERNIGHT...AND PROXIMITY SOUNDINGS ONLY SHOW A VERY SHALLOW
AREA OF NEAR SATURATION. THINK WE MAY SEE SOME VERY SHALLOW GROUND
FOG...BUT WILL LET THE DAY SHIFT TAKE ANOTHER LOOK AT IT BEFORE
ADDING.
THE NEXT CHANCE FOR SNOW COULD ARRIVE MONDAY NIGHT INTO TUESDAY DUE
TO THE ARRIVAL OF THE NEXT MID LEVEL WAVE. CURRENTLY THE SYSTEM IS
SPINNING ACROSS THE INTERMOUNTAIN WEST...AND THE MODELS HAVE COME
INTO GENERAL AGREEMENT THAT IT WILL OPEN UP AND SHIFT ACROSS THE
CENTRAL AND SOUTHERN PLAINS MONDAY INTO TUESDAY. THE FINER DETAILS
REMAIN A BIT DIFFERENT...BUT THE OVERALL MESSAGE FROM THE
DETERMINISTIC MODEL RUNS ALONG WITH THE SREF IS THAT CHANCES OF SNOW
WILL INCREASE MONDAY EVENING IN WESTERN PARTS OF THE FORECAST
AREA...WITH THE CHANCES SPREADING SOUTH AND EAST OVERNIGHT MONDAY
INTO TUESDAY. DISCREPANCIES REMAIN IN THE MODEL GENERATED QPF
FIELDS...BUT BASED ON THE SPEED AND STRENGTH OF THIS SYSTEM IT
APPEARS IT COULD TRY TO GENERATE AN INCH OR SO OF SNOW...PRIMARILY
ACROSS PARTS OF NORTH CENTRAL KANSAS INTO FAR SOUTHERN NEBRASKA.
LONG TERM...WEDNESDAY THROUGH SATURDAY. CONFIDENCE IS REASONABLY
HIGH FOR DRY WEATHER THROUGH THIS 4-DAY PERIOD...ALTHOUGH
CONFIDENCE IN TEMPERATURE TRENDS IS A BIT SHAKY OWING NOT ONLY TO
MODEL DIFFERENCES...BUT ALSO TO UNCERTAINTY IN HOW MUCH IMPACT THE
FRESH SNOW PACK WILL HAVE ON HIGHS. THAT BEING SAID...IT CERTAINLY
LOOKS LIKE AT LEAST SLIGHTLY BELOW-NORMAL TEMPS WILL PERSIST
THROUGH THE PERIOD...AND CURRENT FORECAST MAY NOT BE COLD ENOUGH
AT TIMES...ESPECIALLY OVER THE DEEPER SNOW NEAR/NORTH OF HIGHWAY
6.
STARTING THINGS OUT WEDNESDAY/WEDNESDAY NIGHT...00Z GFS AND ECMWF
RUNS ARE IN REASONABLE AGREEMENT DEPICTING A GENERAL NORTHWEST
FLOW ALOFT OVER THE CENTRAL PLAINS...WITH THE PRIMARY SYNOPTIC LOW
PRESSURE SYSTEMS CONSISTING OF A HUDSON BAY VORTEX WELL TO THE
NORTHEAST...AND A SLOW-MOVING CLOSED LOW OFF BAJA WELL TO THE
SOUTHWEST. MEANWHILE...A LOWER AMPLITUDE MID LEVEL WAVE WILL BE
MOVING AWAY FROM IA EASTWARD. AT THE SURFACE...THERE IS GENERAL
AGREEMENT IN SURFACE HIGH PRESSURE SLIDING EAST DURING THE
DAY...INDUCING SOUTHERLY BREEZES...WHICH THEN TURN MORE WESTERLY
OR POSSIBLY NORTHERLY OVERNIGHT AS THE NEXT COLD FRONT MOVES
IN...BUT THE GFS SOLUTION IS DEFINITELY MUCH MORE AGGRESSIVE WITH
THIS FRONTAL INVASION THAN THE ECMWF. FOR HIGH TEMPS WED...CHANGED
VERY LITTLE FROM PREVIOUS FORECAST...REMAINING A SOLID 3-4 DEGREES
BELOW 00Z MEX GUIDANCE MAINLY TO ACCOUNT FOR SNOW PACK. THIS KEEPS
MOST NEB ZONES ONLY IN THE UPPER 20S...WITH LOW-MID 30S MORE
PREVALENT IN KS ZONES.
THURSDAY/THURSDAY NIGHT...ECMWF/GFS SOLUTIONS AGREE THAT A HIGHLY
AMPLIFIED MID-UPPER RIDGE WILL BUILD OVER THE WESTERN CONUS...BUT
EAST OF THIS FEATURE...THE GFS IS MUCH MORE AGGRESSIVE MOVING A
SHORTWAVE SOUTHWARD THROUGH THE PLAINS...ROTATING AROUND THE MAIN
HUDSON BAY REGION VORTEX. THIS IN TURN MAKES THE GFS MUCH MORE
AGGRESSIVE WITH LOW LEVEL COLD AIR ADVECTION INTO THE CWA. FOR
MOST AREAS KEPT HIGH TEMPS SIMILAR TO BOTH PREVIOUS FORECAST AND
00Z MEX GUIDANCE...WITH LOW 30S OVER DEEPER SNOW AND MID 30S
SOUTH.
FRIDAY/FRIDAY NIGHT...DIFFERENCES WITH SYNOPTIC FEATURES ALOFT
BETWEEN 00Z ECMWF/GFS SOLUTIONS CONTINUE TO MAGNIFY...WITH THE
ECMWF TRYING TO BUILD A SHORTWAVE RIDGE INTO THE CENTRAL PLAINS
MAINLY FRIDAY NIGHT...WHILE THE GFS DROPS AN AMPLIFYING SHORTWAVE
SOUTH THROUGH THE UPPER MS VALLEY/MIDWEST. THIS RESULTS IN A
DRAMATIC DIFFERENCE IN 850MB TEMPS ACROSS THE CWA...AND ALSO WIND
DIRECTION...ESPECIALLY FOR FRIDAY NIGHT WITH THE ECWMF SUGGESTING
OVERNIGHT WARM AIR ADVECTION. THE 00Z GFS ENSEMBLE MEAN 500MB
HEIGHT IS A MIDDLE GROUND BETWEEN THE DETERMINISTIC ECMWF/GFS
SOLUTIONS...AND THUS FOR HIGHS FRIDAY STUCK CLOSE TO MODEL
CONSENSUS WITH MID-UPPER 20S MOST NEB ZONES...AND MID 30S FARTHER
SOUTH. THIS UNDERCUTS 00Z MEX HIGHS BY 2-3 DEGREES MOST AREAS.
FINALLY FOR SATURDAY...CONFIDENCE REALLY GOES IN THE TANK ON THE
SYNOPTIC SCALE PATTERN...WITH THE GFS SHOWING AN EXPANSIVE
COLD SURFACE RIDGE OVER THE PLAINS...WHILE THE ECMWF HAS
IMPRESSIVE WARM ADVECTION AND SOUTHERLY BREEZES AHEAD OF A
SHORTWAVE CROSSING THE CENTRAL ROCKIES. THIS IMPLIES HIGH
TEMPERATURES COULD EASILY RANGE ANYWHERE FROM 20S TO AT LEAST 40S
ACROSS PARTS OF THE CWA...AND FOR NOW WILL PLAY CONSENSUS MIDDLE
GROUND WITH LOW 30S NORTHEAST TO LOW 40S SOUTHWEST. LOTS TO IRON
OUT AT THIS RANGE.
DESPITE THE UPCOMING STRETCH OF BELOW NORMAL TEMPERATURES...EXTENDED
MODELS SHOW NO SIGN OF A LEGITIMATE ARCTIC INVASION. ON ONE FINAL
NOTE...NOW THAT PLENTY OF SNOW IS ON THE GROUND AND LOOKS TO BE
SLOW TO FULLY MELT...THERE COULD EASILY BE POTENTIAL FOR FOG
AND/OR LOW STRATUS DURING THE NEXT WEEK...WITH THE DETAILS JUST
TOO MURKY TO RESOLVE AT THIS TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
SHORT TERM...KING
LONG TERM/AVIATION...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1022 AM EST SUN FEB 5 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL PASS THROUGH TODAY...WITH CLOUDS
AND A FEW FLURRIES MAINLY ACROSS CENTRAL NEW YORK. OTHERWISE...DRY
WEATHER WILL CONTINUE INTO THE FIRST PART OF THE WORK WEEK AS HIGH
PRESSURE BUILDS INTO THE REGION FROM THE MIDWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
1015 AM UPDATE...AS HAS BEEN THE CASE THE LAST FEW DAYS...STRUGGLE
OF THE DAY AGAIN IS STRATOCUMULUS THAT THE MODELS ARE FAILING TO
CAPTURE. MOST UPDATED RUC MODEL...ESPECIALLY RH AROUND
850MB...SEEMS TO HAVE THE BEST HANDLE OF CURRENT SITUATION. SKY
GRIDS WERE INCREASED SIGNIFICANTLY ESPECIALLY FOR THE NEW YORK
ZONES FOR TODAY...AND AS A RESULT...TEMPERATURES WERE ADJUSTED
LOWER. ALSO...COMBINATION OF VORTICITY LOBE SWINGING THROUGH
ALOFT...AND MESOVORTEX THAT DEVELOPED OVER WESTERN LAKE
ONTARIO...WILL ENHANCE THINGS ENOUGH TO PRODUCE A FEW NON-
ACCUMULATING FLURRIES FOR MUCH OF CENTRAL NEW YORK. LATE IN THE
DAY...DIURNAL TIMING...WARM AIR ADVECTION ALOFT...AND BACKING OF
LOW LEVEL FLOW WILL HELP TO BREAK UP THE CLOUDS COVER HEADING INTO
TONIGHT...THOUGH CLOUDS AND A FEW FLURRIES WILL STILL BE POSSIBLE
NORTH OF THE THRUWAY THIS EVENING.
ANOTHER RIPPLE IN THE FLOW COULD SKIM THE AREA WITH BRIEF AXIS OF
MID/HIGH LEVEL CLOUDS OVERNIGHT...BUT OVERALL LOOKING AT LITTLE
CLOUD COVER DURING THE PREDAWN HOURS MONDAY MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
MORE QUIET WX IN THE SHRT TERM AS NRN STREAM ENERGY STAYS
NORTH...AND DEEP SRN STREAM MOISTURE REMAINS SOUTH. LRG SFC HIPRES
OVER THE MIDDLE OF THE COUNTRY NOSES EAST TO THE MID ATLANTIC
KEEPING THE AREA DRY YET IN A MILD WLY FLOW. ONLY SYSTEM OF NOTE
IN THE PD IS A SHALLOW COLD FNT DROPPING IN FROM THE NORTH TUE.
FNT WILL BRING CLDS AND PERHAPS A FEW FLURRIES...ESP OVER THE
FINGER LAKES AS THE FLOW WITH THE CAA IS MORE NLY THAN NW.
HWVR...AIR IS JUST NOT ALL THAT COLD SO LE WILL BE VERY LIMITED
AND PRBLY COMFINED TO THE AREA OF THE FNT WITH THE ENHANCED LIFT.
TEMPS WILL CONT WELL ABV NRML IN THE PD. MODEL GUID WAS IN GOOD
GNRL AGREEMENT FOR THE PD SO OVERALL CONFIDENCE IN THE FCST IS
HIGH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPDATED AS OF 330 PM SAT... OVERALL...NOT A GREAT DEAL OF CHG TO THE
LARGE-SCALE PATTERN SEEN WITH THE MODELS AGAIN TODAY.
EC/GFS/ENSEMBLE CONSENSUS SUGGESTS THAT A VORTEX WILL REMAIN IN
PLACE NEAR HUDSON`S BAY...WITH UPPER-LVL RIDGING OVER WRN CANADA.
ALTHOUGH THIS WILL KEEP FAST MOVG NRN STREAM DISTURBANCES COMING
ACRS NY/PA ABT EVERY 24-36 HRS...IT WILL ALSO KEEP THE GOMEX CUT
OFF. THIS FACTOR...IN COMBINATION WITH A CONTINUED LACK OF SIG HI-
LAT BLOCKING OVER GREENLAND/NWRN ATLANTIC...SHOULD KEEP ANY MAJOR
STORMS/HVY PCPN EVENTS FROM IMPACTING OUR FA THIS PD. ALSO...GIVEN
THE LACK OF SNOW COVER...AND THE LIKELIHOOD THAT THE CORE OF THE
ARCTIC AIR WILL REMAIN N OF THE CANADA/U.S. BORDER...TEMPS SHOULD
CONTINUE TO AVERAGE NEAR TO SOMEWHAT ABV SEASONAL NORMS FOR EARLY FEB.
DAILY WX-WISE...A FAST MOVG UPPER-LVL TROUGH/SFC WAVE ARE EXPECTED
TO UNDERCUT THE ABV MENTIONED ERN CANADIAN VORTEX AND TRACK
THROUGH THE MID-ATL RGN WED...OR PERHAPS EARLY THU. THIS SYSTEM
COULD BRING A SHOT OF LGT SNOW...ALTHOUGH THE NRN EXTENT OF THE
PCPN IS UNCERTAIN ATTM. BOTTOM LN THOUGH...THIS SYSTEM SHOULDN`T
HAVE TIME TO PICK UP MUCH MOIST...SO AGN ANY SNOW LOOKS LIGHT.
OTHERWISE (FROM LATER THU INTO NEXT WEEKEND)...QUICK MOVG IMPULSES
IN THE NRN STREAM WILL REINFORCE POLAR ORIGIN AIR MASSES (HIGHS
MAINLY IN THE 30S...WITH NIGHTTIME LOWS IN THE TEENS AND 20S).
OVERALL...THESE AIR MASSES LOOK INSUFFICIENTLY COLD/MOIST TO
GENERATE MUCH OF A LAKE RESPONSE...SO JUST OCNL FLRYS/-SHSN WILL
BE CALLED FOR IN THE FCST.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
UPDATED AS OF 630 AM SUN... VFR CONDITIONS EXPECTED TODAY WITH BKN-
OVC CLOUDS WITH HTS OF GENERALLY 3 TO 5 KFT. SKIES WILL BECOME
MAINLY CLEAR TONIGHT... EXCEPT FOR SOME PATCHY CLOUDS POSSIBLY
LINGERING AT RME AND SYR. CLOUD HTS WILL BE VFR ABV 3000 FEET.
WINDS WILL BE LIGHT AND VARIABLE BECOMING NW AT 5 TO 10 KTS
TODAY... AND WSW AT LESS THAN 10 KTS TONIGHT.
.OUTLOOK...
MON NGT-TUE NGT...PSBL MVFR/IFR IN LAKE-EFFECT SHSN.
WED...MAINLY VFR...BUT MVFR POSSIBLE TOWARD EVENING IN LGT SNOW.
THU AND FRIDAY...MVFR/IFR PSBL IN LGT SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...MLJ
AVIATION...MSE
AREA FORECAST DISCUSSION...CORRECTED
NWS BISMARCK ND
432 AM CST SUN FEB 5 2012
.SHORT TERM...TODAY THROUGH MONDAY...
THE CHALLENGE FOR THE MORNING IS ONCE AGAIN PREDICTING THE
DISSIPATION OF FOG AND LOW STRATUS CONFINED MOSTLY TO AREAS ALONG
AND NORTH AND EAST OF THE MISSOURI RIVER. THE DETERMINISTIC
MODELS ARE HAVING A VERY DIFFICULT TIMING RESOLVING THE
STRATUS...WITH THE 06 UTC HRRR THE ONLY MODEL WITH A HANDLE ON THE
EVENT...SUGGESTING DISSIPATION OF THE FOG AND STRATUS BY EARLY
AFTERNOON AT THE LATEST AS MIXING INCREASING AHEAD OF A SURFACE
TROUGH. HAVE TRENDED SLIGHTLY FASTER THAN THE
HRRR...HOWEVER...MUCH UNCERTAINTY AS TO WHEN THE STRATUS WILL
COMPLETELY DISSIPATE DOES REMAIN. HAVE REMOVED MORTON AND SIOUX
COUNTIES FROM THE DENSE FOG ADVISORY...AND WILL LEAVE THE
REMAINING COUNTIES IN PLACE THROUGH 15 UTC. TWO OTHER PATCHES OF
DENSE FOG ARE BEING OBSERVED AS OF 09 UTC...INCLUDING THE
WILLISTON THROUGH TIOGA AREAS AND RUGBY THROUGH BOTTINEAU. DUE TO
THE VERY LOCALIZED NATURE OF THESE AREAS...WILL COVER WITH AN SPS.
A VERY MILD EARLY FEBRUARY DAY IS FORECAST ACROSS WESTERN AND
CENTRAL NORTH DAKOTA TODAY DUE IN LARGE PART TO THE ABSENCE OF SNOW
COVER ACROSS THE AREA. THE ABUNDANCE OF BROWN GROUND WILL YIELD
GREATER MIXING HEIGHTS ENABLING THE RELATIVELY MILD TEMPERATURES IN
THE 850-800 MB LAYER OF +4 TO +6 C TO BE MIXED TO THE
SURFACE...RESULTING IN WIDESPREAD 50S FOR HIGH TEMPERATURES FOR MOST
AREAS...ESPECIALLY ALONG AND SOUTH OF THE MISSOURI RIVER...WITH
UPPER 40S FOR HIGHS FOR THE JAMES RIVER VALLEY...TURTLE MOUNTAINS
AND LOCATIONS ALONG THE INTERNATIONAL BORDER. TRENDED WELL ABOVE
THE DETERMINISTIC AND STATISTICAL CONSENSUS AND OPTED FOR THE SUPERIOR
VERIFICATION OF BIAS CORRECTED GUIDANCE GIVEN THE BROWN WINTER WE
ARE HAVING. SHOWN BELOW ARE THE FORECAST HIGHS AND RECORD HIGHS
FOR TODAY FOR THE MAJOR OBSERVING LOCATIONS. SEE THE FIRE WEATHER
DISCUSSION BELOW REGARDING FIRE DANGER FOR TODAY.
LOCATION........FORECAST...........RECORD
BISMARCK..........53...............56 1991
JAMESTOWN.........49...............58 1991
MINOT.............54...............58 1963
WILLISTON.........51...............55 1963
DICKINSON.........54...............58 1963
A SURFACE COLD FRONT IS FORECAST TO CROSS THE INTERNATIONAL BORDER
AROUND 00 UTC THIS EVENING AND PROPAGATE SOUTH THROUGH THE
NIGHT...ENTERING SOUTH DAKOTA BETWEEN 08 AND 10 UTC. GIVEN POST
FRONTAL MIXING AND WARM TEMPERATURES TO BEGIN THE OVERNIGHT...LOW
TEMPERATURES SUNDAY NIGHT SHOULD ONLY FALL INTO THE LOW 20S FOR MOST
LOCATIONS...WITH TEENS ALONG THE INTERNATIONAL BORDER. A BREEZY
MONDAY IS EXPECTED IN THE WAKE OF THE COLD FRONT AS 1045 MB SURFACE
HIGH BEGINS TO BUILD INTO THE STATE. AIDED BY AN AN ISALLOBARIC
COMPONENT FROM PRESSURE RISES AND LOW LEVEL COLD AIR ADVECTION
PROMOTING MIXING TO AROUND 825 MB...NORTHERLY WIND GUSTS TO 25 KTS
ARE EXPECTED FOR MOST AREAS WITH FLURRIES ASSOCIATED WITH STRATUS
APPROXIMATELY ALONG AND NORTH OF A LINE FROM CROSBY THROUGH
WASHBURN THROUGH EDGELEY. DESPITE THE COLD FRONTAL
PASSAGE...TEMPERATURES ON MONDAY WILL STILL BE ABOVE NORMAL THANKS
TO NO SNOWPACK WITH HIGHS FROM THE LOW TO MID 20S NORTH TO THE
LOWER 30S SOUTH.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY...
MODELS IN FAIR AGREEMENT WITH FEATURES IN LONG TERM. USED THE BLEND
WITH FEW CHANGES. LARGE MID AND UPPER LEVEL RIDGE LIES ALONG SPINE
OF THE ROCKIES WITH FAIRLY STRONG HIGH PRESSURE DROPPING SOUTH IN
LEE OF CANADIAN ROCKIES. 1044 HIGH WOULD INDICATE A VERY CHILLY
MIDDLE OF THE WEEK...HOWEVER WITH NO SIGNIFICANT SNOW COVER UPSTREAM
FROM THE THE CENTRAL ALBERTA AND SASKATCHEWAN BORDER...SOUTH THROUGH
THE NORTHERN PLAINS...TEMPERATURES WILL BE NORMAL OR SEVERAL DEGREES
ABOVE NORMAL.
ONLY ONE CHANCE OF ACCUMULATING PRECIPITATION WHICH WILL COME
WEDNESDAY NIGHT AS A REINFORCING SHOT OF MODIFIED ARCTIC AIR MOVES
SOUTH BEHIND A COLD FRONT. THE SYSTEM LOOKS QUITE DRY AND THE
HIGHEST POPS...SLIGHT CHANCE...ARE IN THAT PERIOD. WHILE AIR WILL BE
COLDER...THICKNESS AND 85H TEMPERATURES INDICATE THAT THE COLDEST
AIR WILL PASS JUST TO THE EAST OF THE FORECAST AREA BORDER.
&&
.AVIATION...
BAND OF STRATUS EXTENDS ABOUT 50 MILES EITHER SIDE OF MISSOURI
VALLEY FROM THE SOUTH DAKOTA BORDER NORTH TO NEAR LAKE
SAKAKAWEA...THEN NORTHEAST TO WILLISTON. SEVERAL OTHER MUCH SMALLER
BANDS LINGERED OVER EASTERN PORTIONS OF THE FORECAST AREA...KJMS AND
EAST AND KRUG AND EAST. THE AREAS SHOWED LITTLE MOVEMENT...BUT WERE
SLOWLY SHRINKING IN AREAL COVERAGE. HOWEVER THE MISSOURI VALLEY
ESPECIALLY FROM KBIS TO KISN WILL LINGER IN LIFR CONDITIONS FOR
SEVERAL MORE HOURS BEFORE A TRANSITION OF VFR BY THE AFTERNOON ALL
AERODROME SITES.
&&
.FIRE WEATHER...
SUNDAY LOOKS TO BE VERY MILD ACROSS WESTERN AND CENTRAL NORTH
DAKOTA WITH HIGHS IN 50S. WITH PLENTIFUL DRY VEGETATION IN
PLACE...AND AFTERNOON RELATIVE HUMIDITY VALUES EXPECTED TO FALL
INTO THE 25 TO 35 PERCENT RANGE ESPECIALLY ALONG AND SOUTH OF THE
MISSOURI RIVER...THE ONE THING PREVENTING FIRE WEATHER CONCERNS
ARE WIND SPEEDS ONLY ON THE ORDER OF 10 TO 15 MPH.
HOWEVER...THE FIRE DANGER ON MONDAY IS FORECAST TO BE MEDIUM TO
HIGH ACROSS THE AREA...WITH NORTHERLY WINDS OF 20 TO 30 MPH BEHIND
A COLD FRONT...WITH HIGH TEMPERATURES IN THE UPPER 20S TO LOWER 30S.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL 9 AM CST THIS MORNING FOR NDZ035>037-
046-047-050.
&&
$$
SHORT TERM/FIRE...PJA
LONG TERM/AVIATION....HW
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
1019 AM EST SUN FEB 5 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. COLD FRONT PASSES TUESDAY NIGHT
FOLLOWED BY A WEAK WAVE MIDWEEK. ANOTHER COLD FRONT CROSSES FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
930 AM UPDATE...
FINED TUNED CLEARING LINE FOR THE AFTERNOON AND ADJUSTED
TEMPERATURES UP N / DOWN S. OTHERWISE FCST ON TRACK WITH THE LAST
OF THE LIGHT PRECIPITATION / DRIZZLE WINDING DOWN.
730 AM UPDATE...
ADJUSTED POPS TO BETTER HANDLE LAST BAND OF RAIN PUSHING DOWN FROM
THE N...ASSOCIATED WITH FRONT UP AROUND H85 LEVEL. ALSO ADDED
DRIZZLE AND AREAS OF FOG. OTHERWISE FORECAST ON TRACK INCLUDING
CLEARING TREND FROM N TO S ON DRY ADVECTION BEHIND FRONT PUSHING
SAME DIRECTION.
PREV DISCN...
CONSIDERABLE DIFFERENCES BETWEEN THE NAM AND GFS WITH THE HANDLING
OF THE LOW LEVEL MOISTURE TODAY. RUC SUPPORTS THE FASTER CLEARING
FOUND IN THE GFS. THEREFORE WILL LEAN MORE TOWARD THE FASTER
SOLUTION. WITH CALM WINDS TONIGHT AND DECENT RADIATION
CONDITIONS...WILL GO TOWARD THE LOWER END OF THE MOS GUIDANCE. WILL
ALSO INCLUDE VALLEY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
MDLS ARE STARTING TO CONVERGE ON HANDLING OF UPR LOW POISED TO MOVE
THRU ON MON. NAM/SREF CONT TO OPEN THIS UP INTO A WAVE ON
APPROACH...WITH REMAINDER OF GLOBAL MDLS KEEPING A STRONGER INTACT
CLOSED LOW AT H5. WILL FOLLOW HPC PREFERENCE FOR A ECWMF/GFS
BLEND...NOTING NAM TO BE AN OUTLIER ATTM. GIVEN THAT...WILL INCREASE
CLDS ACROSS S BY 18Z...WITH MOISTENING OF THE COLUMN THRU H7. WEAK
LIFT IN THIS LAYER AIDED BY UPR LOW SHOULD ALLOW LIGHT PRECIPITATION
TO BREAK OUT ACROSS SW VA...SOUTHERN COAL FIELDS AND SOUTHERN AND
CENTRAL WV MTNS BY AFTN. GLOBAL MDLS DO INDICATE QPF WITH
THIS...ALBEIT VERY LIGHT. THEREFORE...INTRODUCED CHC POPS ACROSS
AFOREMENTIONED AREAS...MAINLY FOR AFTN AND EARLY EVE. TEMP PROFILES
SUPPORT MAINLY LIQUID...PERHAPS ENDING AS A FEW WET FLAKES ACROSS
THE MTNS EARLY EVE. WILL SEE A SHARP LINE BETWEEN SUN AND CLDS.
THINK AREAS NORTH OF I64 CORRIDOR WILL SEE MAINLY SUNSHINE.
LOOKING AT QUIET WX FOR TUE UNDER SFC HIGH. A S/W TROF MAY BRING A
FEW SHRA/SHSN TO THE AREA WED. IF NOTHING ELSE...WILL INCREASE THE
CLDS.
GUIDANCE VERY SIMILAR TO INHERITED NUMBERS...SO LITTLE CHANGE
NECESSARY. HOWEVER...MAY SEE SOMEWHAT OF A TEMP GRADIENT MON WHERE
SE OH AND NORTHERN WV ENDS UP WARMER THAN SOUTHERN AREAS DUE TO CLDS.
OVERALL LOOKING AT AN ABV NORMAL PERIOD THRU MIDWEEK...NOTHING NEW
THIS WINTER.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
ZONAL FLOW TO START TRANSITIONS TO NW FLOW THIS PERIOD AS LONG WAVE
TROUGH AMPLIFIES IN THE E. THIS LONG WAVE WILL LIKELY BE TRANSIENT
AGAIN THOUGH PER ONGOING LACK OF HIGH LATITUDE BLOCKING...TO WHICH
THE LACK OF DEEP PENETRATION OF ARCTIC AIR DOWN INTO THE EASTERN
CONUS IS ALSO ATTRIBUTABLE.
PERIOD STARTS DRY TUE NT WITH HIGH PRESSURE GIVING WAY TO A MOISTURE
STARVED COLD FRONT WITH NO INFLOW FROM THE S. THAT FRONT PASSES
EARLY WED...FOLLOWED BY A WAVE AND UPPER LEVEL S/W TROF THAT CROSS
WED INTO WEDNESDAY NT. CARRIED CHANCE POPS FOR THIS IN KEEPING WITH
HPC...WHICH FOLLOWS THE ECMWF AND THEN THE ECENS MEAN WHICH BECOMES
A GOOD REPRESENTATION OF THE MODEL AVERAGE LATER IN THE PERIOD.
WEAK SFC HIGH PRESSURE FOR THU ALTHOUGH ANOTHER UPPER LEVEL S/W TROF
ALSO CROSSES.
A STRONGER COLD FRONT DROPS DOWN FRI AS THE EASTERN CONUS LONG WAVE
TROF BEGINS TO SET UP. CARRIED THE CHANCE FOR PRECIPITATION WITH
THIS STRONGER FRONT ALTHOUGH MOISTURE WILL AGAIN BE LIMITED...AGAIN
KEEPING CLOSE TO HPC GUIDANCE.
ADJUSTED TEMPERATURES TO OR TOWARD HPC EARLY ON WHICH ENTAILED
HIGHER VALUES WED AND LOWER VALUES THU AND THU NT. WENT LOWER THAN
HPC BEYOND THAT IN DEFERENCE TO THE MEX AND ISC. AGAIN THOUGH THERE
IS SOME QUESTION AS TO HOW MUCH COLDER IT GETS ONCE THE SECOND FRONT
ROLLS THROUGH.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
930 AM UPDATE...
LOW CIGS TAKING LONGER TO LIFT...LASTING WELL INTO HE AFTERNOON
ACROSS THE S. YET ANOTHER BATCH OF IFR CLOUD HEADING S OUT OF PA
AFFECTING NORTHERN SITES INTO THE AFTERNOON DESPITE EARLIER
EXPECTATIONS OF CLEARING THERE. PKB NEAR EDGE OF THIS DECK.
PREV DISCN...
A LOW PRESSURE SYSTEM MOVING SOUTH OF THE REGION WAS CREATING
IFR/LIFR CONDITIONS. SOME DRIER AIR WILL SLOWLY PUSH SOUTHEASTWARD
ACROSS THE REGION DURING THE DAY...ALLOWING FOR CONDITIONS TO
GRADUALLY CHANGE TO VFR FROM NORTHWEST TO SOUTHEAST TODAY. VFR
CONDITIONS CAN THEN BE EXPECTED THIS EVENING. VALLEY FOG IS EXPECTED
TO FORM LATE SUNDAY NIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CEILINGS AND VISIBILITIES IMPROVING
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M M M M L M M H H H H
HTS CONSISTENCY H H M H M M M H H H H H
BKW CONSISTENCY L L L M M H L L H M H H
EKN CONSISTENCY L L L M L H M H H H H H
PKB CONSISTENCY M M M M H H H H H H H H
CKB CONSISTENCY L L H M L L M H H H H H
AFTER 12Z MONDAY...
IFR/LIFR POSSIBLE IN VALLEY FOG MONDAY MORNING...ESPECIALLY IN
MOUNTAINS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...TRM/RPY
SHORT TERM...30
LONG TERM...TRM
AVIATION...RPY
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
759 AM EST SUN FEB 5 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. COLD FRONT PASSES TUESDAY NIGHT
FOLLOWED BY A WEAK WAVE MIDWEEK. ANOTHER COLD FRONT CROSSES FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
730 AM UPDATE...
ADJUSTED POPS TO BETTER HANDLE LAST BAND OF RAIN PUSHING DOWN FROM
THE N...ASSOCIATED WITH FRONT UP AROUND H85 LEVEL. ALSO ADDED
DRIZZLE AND AREAS OF FOG. OTHERWISE FORECAST ON TRACK INCLUDING
CLEARING TREND FROM N TO S ON DRY ADVECTION BEHIND FRONT PUSHING
SAME DIRECTION.
PREV DISCN...
CONSIDERABLE DIFFERENCES BETWEEN THE NAM AND GFS WITH THE HANDLING
OF THE LOW LEVEL MOISTURE TODAY. RUC SUPPORTS THE FASTER CLEARING
FOUND IN THE GFS. THEREFORE WILL LEAN MORE TOWARD THE FASTER
SOLUTION. WITH CALM WINDS TONIGHT AND DECENT RADIATION
CONDITIONS...WILL GO TOWARD THE LOWER END OF THE MOS GUIDANCE. WILL
ALSO INCLUDE VALLEY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
MDLS ARE STARTING TO CONVERGE ON HANDLING OF UPR LOW POISED TO MOVE
THRU ON MON. NAM/SREF CONT TO OPEN THIS UP INTO A WAVE ON
APPROACH...WITH REMAINDER OF GLOBAL MDLS KEEPING A STRONGER INTACT
CLOSED LOW AT H5. WILL FOLLOW HPC PREFERENCE FOR A ECWMF/GFS
BLEND...NOTING NAM TO BE AN OUTLIER ATTM. GIVEN THAT...WILL INCREASE
CLDS ACROSS S BY 18Z...WITH MOISTENING OF THE COLUMN THRU H7. WEAK
LIFT IN THIS LAYER AIDED BY UPR LOW SHOULD ALLOW LIGHT PRECIPITATION
TO BREAK OUT ACROSS SW VA...SOUTHERN COAL FIELDS AND SOUTHERN AND
CENTRAL WV MTNS BY AFTN. GLOBAL MDLS DO INDICATE QPF WITH
THIS...ALBEIT VERY LIGHT. THEREFORE...INTRODUCED CHC POPS ACROSS
AFOREMENTIONED AREAS...MAINLY FOR AFTN AND EARLY EVE. TEMP PROFILES
SUPPORT MAINLY LIQUID...PERHAPS ENDING AS A FEW WET FLAKES ACROSS
THE MTNS EARLY EVE. WILL SEE A SHARP LINE BETWEEN SUN AND CLDS.
THINK AREAS NORTH OF I64 CORRIDOR WILL SEE MAINLY SUNSHINE.
LOOKING AT QUIET WX FOR TUE UNDER SFC HIGH. A S/W TROF MAY BRING A
FEW SHRA/SHSN TO THE AREA WED. IF NOTHING ELSE...WILL INCREASE THE
CLDS.
GUIDANCE VERY SIMILAR TO INHERITED NUMBERS...SO LITTLE CHANGE
NECESSARY. HOWEVER...MAY SEE SOMEWHAT OF A TEMP GRADIENT MON WHERE
SE OH AND NORTHERN WV ENDS UP WARMER THAN SOUTHERN AREAS DUE TO CLDS.
OVERALL LOOKING AT AN ABV NORMAL PERIOD THRU MIDWEEK...NOTHING NEW
THIS WINTER.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
ZONAL FLOW TO START TRANSITIONS TO NW FLOW THIS PERIOD AS LONG WAVE
TROUGH AMPLIFIES IN THE E. THIS LONG WAVE WILL LIKELY BE TRANSIENT
AGAIN THOUGH PER ONGOING LACK OF HIGH LATITUDE BLOCKING...TO WHICH
THE LACK OF DEEP PENETRATION OF ARCTIC AIR DOWN INTO THE EASTERN
CONUS IS ALSO ATTRIBUTABLE.
PERIOD STARTS DRY TUE NT WITH HIGH PRESSURE GIVING WAY TO A MOISTURE
STARVED COLD FRONT WITH NO INFLOW FROM THE S. THAT FRONT PASSES
EARLY WED...FOLLOWED BY A WAVE AND UPPER LEVEL S/W TROF THAT CROSS
WED INTO WEDNESDAY NT. CARRIED CHANCE POPS FOR THIS IN KEEPING WITH
HPC...WHICH FOLLOWS THE ECMWF AND THEN THE ECENS MEAN WHICH BECOMES
A GOOD REPRESENTATION OF THE MODEL AVERAGE LATER IN THE PERIOD.
WEAK SFC HIGH PRESSURE FOR THU ALTHOUGH ANOTHER UPPER LEVEL S/W TROF
ALSO CROSSES.
A STRONGER COLD FRONT DROPS DOWN FRI AS THE EASTERN CONUS LONG WAVE
TROF BEGINS TO SET UP. CARRIED THE CHANCE FOR PRECIPITATION WITH
THIS STRONGER FRONT ALTHOUGH MOISTURE WILL AGAIN BE LIMITED...AGAIN
KEEPING CLOSE TO HPC GUIDANCE.
ADJUSTED TEMPERATURES TO OR TOWARD HPC EARLY ON WHICH ENTAILED
HIGHER VALUES WED AND LOWER VALUES THU AND THU NT. WENT LOWER THAN
HPC BEYOND THAT IN DEFERENCE TO THE MEX AND ISC. AGAIN THOUGH THERE
IS SOME QUESTION AS TO HOW MUCH COLDER IT GETS ONCE THE SECOND FRONT
ROLLS THROUGH.
&&
.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
A LOW PRESSURE SYSTEM MOVING SOUTH OF THE REGION WAS CREATING
IFR/LIFR CONDITIONS. SOME DRIER AIR WILL SLOWLY PUSH SOUTHEASTWARD
ACROSS THE REGION DURING THE DAY...ALLOWING FOR CONDITIONS TO
GRADUALLY CHANGE TO VFR FROM NORTHWEST TO SOUTHEAST TODAY. VFR
CONDITIONS CAN THEN BE EXPECTED THIS EVENING. VALLEY FOG IS EXPECTED
TO FORM LATE SUNDAY NIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CEILINGS AND VISIBILITIES IMPROVING
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M M M M L M M H H H H
HTS CONSISTENCY H H M H M M M H H H H H
BKW CONSISTENCY L L L M M H L L H M H H
EKN CONSISTENCY L L L M L H M H H H H H
PKB CONSISTENCY M M M M H H H H H H H H
CKB CONSISTENCY L L H M L L M H H H H H
AFTER 12Z MONDAY...
IFR/LIFR POSSIBLE IN VALLEY FOG MONDAY MORNING...ESPECIALLY IN
MOUNTAIN VALLEYS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...TRM/RPY
SHORT TERM...30
LONG TERM...TRM
AVIATION...RPY
AREA FORECAST DISCUSSION
NWS CHARLESTON WV
536 AM EST SUN FEB 5 2012
.SYNOPSIS...
HIGH PRESSURE BUILDS IN TODAY. COLD FRONT PASSES TUESDAY NIGHT
FOLLOWED BY A WEAK WAVE MIDWEEK. ANOTHER COLD FRONT CROSSES FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
CONSIDERABLE DIFFERENCES BETWEEN THE NAM AND GFS WITH THE HANDLING
OF THE LOW LEVEL MOISTURE TODAY. RUC SUPPORTS THE FASTER CLEARING
FOUND IN THE GFS. THEREFORE WILL LEAN MORE TOWARD THE FASTER
SOLUTION. WITH CALM WINDS TONIGHT AND DECENT RADIATION
CONDITIONS...WILL GO TOWARD THE LOWER END OF THE MOS GUIDANCE. WILL
ALSO INCLUDE VALLEY FOG.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/...
MDLS ARE STARTING TO CONVERGE ON HANDLING OF UPR LOW POISED TO MOVE
THRU ON MON. NAM/SREF CONT TO OPEN THIS UP INTO A WAVE ON
APPROACH...WITH REMAINDER OF GLOBAL MDLS KEEPING A STRONGER INTACT
CLOSED LOW AT H5. WILL FOLLOW HPC PREFERENCE FOR A ECWMF/GFS
BLEND...NOTING NAM TO BE AN OUTLIER ATTM. GIVEN THAT...WILL INCREASE
CLDS ACROSS S BY 18Z...WITH MOISTENING OF THE COLUMN THRU H7. WEAK
LIFT IN THIS LAYER AIDED BY UPR LOW SHOULD ALLOW LIGHT PRECIPITATION
TO BREAK OUT ACROSS SW VA...SOUTHERN COAL FIELDS AND SOUTHERN AND
CENTRAL WV MTNS BY AFTN. GLOBAL MDLS DO INDICATE QPF WITH
THIS...ALBEIT VERY LIGHT. THEREFORE...INTRODUCED CHC POPS ACROSS
AFOREMENTIONED AREAS...MAINLY FOR AFTN AND EARLY EVE. TEMP PROFILES
SUPPORT MAINLY LIQUID...PERHAPS ENDING AS A FEW WET FLAKES ACROSS
THE MTNS EARLY EVE. WILL SEE A SHARP LINE BETWEEN SUN AND CLDS.
THINK AREAS NORTH OF I64 CORRIDOR WILL SEE MAINLY SUNSHINE.
LOOKING AT QUIET WX FOR TUE UNDER SFC HIGH. A S/W TROF MAY BRING A
FEW SHRA/SHSN TO THE AREA WED. IF NOTHING ELSE...WILL INCREASE THE
CLDS.
GUIDANCE VERY SIMILAR TO INHERITED NUMBERS...SO LITTLE CHANGE
NECESSARY. HOWEVER...MAY SEE SOMEWHAT OF A TEMP GRADIENT MON WHERE
SE OH AND NORTHERN WV ENDS UP WARMER THAN SOUTHERN AREAS DUE TO CLDS.
OVERALL LOOKING AT AN ABV NORMAL PERIOD THRU MIDWEEK...NOTHING NEW
THIS WINTER.
&&
.LONG TERM /THURSDAY THROUGH SATURDAY/...
ZONAL FLOW TO START TRANSITIONS TO NW FLOW THIS PERIOD AS LONG WAVE
TROUGH AMPLIFIES IN THE E. THIS LONG WAVE WILL LIKELY BE TRANSIENT
AGAIN THOUGH PER ONGOING LACK OF HIGH LATITUDE BLOCKING...TO WHICH
THE LACK OF DEEP PENETRATION OF ARCTIC AIR DOWN INTO THE EASTERN
CONUS IS ALSO ATTRIBUTABLE.
PERIOD STARTS DRY TUE NT WITH HIGH PRESSURE GIVING WAY TO A MOISTURE
STARVED COLD FRONT WITH NO INFLOW FROM THE S. THAT FRONT PASSES
EARLY WED...FOLLOWED BY A WAVE AND UPPER LEVEL S/W TROF THAT CROSS
WED INTO WEDNESDAY NT. CARRIED CHANCE POPS FOR THIS IN KEEPING WITH
HPC...WHICH FOLLOWS THE ECMWF AND THEN THE ECENS MEAN WHICH BECOMES
A GOOD REPRESENTATION OF THE MODEL AVERAGE LATER IN THE PERIOD.
WEAK SFC HIGH PRESSURE FOR THU ALTHOUGH ANOTHER UPPER LEVEL S/W TROF
ALSO CROSSES.
A STRONGER COLD FRONT DROPS DOWN FRI AS THE EASTERN CONUS LONG WAVE
TROF BEGINS TO SET UP. CARRIED THE CHANCE FOR PRECIPITATION WITH
THIS STRONGER FRONT ALTHOUGH MOISTURE WILL AGAIN BE LIMITED...AGAIN
KEEPING CLOSE TO HPC GUIDANCE.
ADJUSTED TEMPERATURES TO OR TOWARD HPC EARLY ON WHICH ENTAILED
HIGHER VALUES WED AND LOWER VALUES THU AND THU NT. WENT LOWER THAN
HPC BEYOND THAT IN DEFERENCE TO THE MEX AND ISC. AGAIN THOUGH THERE
IS SOME QUESTION AS TO HOW MUCH COLDER IT GETS ONCE THE SECOND FRONT
ROLLS THROUGH.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
A LOW PRESSURE SYSTEM MOVING SOUTH OF THE REGION WAS CREATING
IFR/LIFR CONDITIONS. SOME DRIER AIR WILL SLOWLY PUSH SOUTHEASTWARD
ACROSS THE REGION DURING THE DAY...ALLOWING FOR CONDITIONS TO
GRADUALLY CHANGE TO VFR FROM NORTHWEST TO SOUTHEAST TODAY. VFR
CONDITIONS CAN THEN BE EXPECTED THIS EVENING. VALLEY FOG IS EXPECTED
TO FORM LATE SUNDAY NIGHT.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 12Z MONDAY...
FORECAST CONFIDENCE: MEDIUM.
ALTERNATE SCENARIOS: TIMING OF CEILINGS AND VISIBILITIES IMPROVING
COULD VARY.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
UTC 1HRLY 11 12 13 14 15 16 17 18 19 20 21 22
EST 1HRLY 06 07 08 09 10 11 12 13 14 15 16 17
CRW CONSISTENCY M M M M M L M M H H H H
HTS CONSISTENCY H H M H M M M H H H H H
BKW CONSISTENCY L L L M M H L L H M H H
EKN CONSISTENCY L L L M L H M H H H H H
PKB CONSISTENCY M M M M H H H H H H H H
CKB CONSISTENCY L L H M L L M H H H H H
AFTER 12Z MONDAY...
IFR/LIFR POSSIBLE IN VALLEY FOG MONDAY MORNING...ESPECIALLY IN
MOUNTAIN VALLEYS.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.
&&
$$
SYNOPSIS...TRM/RPY/30
NEAR TERM...RPY
SHORT TERM...30
LONG TERM...TRM
AVIATION...RPY
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
1016 AM EST SUN FEB 5 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE OVER THE GREAT LAKES WILL BUILD SOUTHEAST
ACROSS PENNSYLVANIA OVER THE NEXT COUPLE OF DAYS. A SERIES OF
SHORTWAVES WILL CARVE OUT A DEEPENING TROUGH ACROSS THE EASTERN
CONUS BY THE END OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID CLOUD SHIELD ASSOCIATED WITH DEPARTING WAVE CONTINUING TO EXIT
THE SOUTH CENTRAL MOUNTAINS AND LOWER SUSQ RIVER VALLEY...AND
SHOULD MOVE OUT IN TIME TO BRING A CRISP AND SUNNY AFTERNOON. LOW
CLOUDS STREAMING SOUTH-SOUTHEASTWARD FROM THE EASTERN GLAKS HAVE
REACHED THE NORTHERN TIER BUT ARE BEING ENTRAINED BY DRY AIR AND
DISSIPATE IN THE DOWNSLOPING NORTHERLY FLOW FROM THE N CENTRAL
MOUNTAINS. SO WHILE SOME INCREASE IN LLVL CLOUDINESS WILL CONTINUE
TO TAKE PLACE...DO NOT THINK WIDESPREAD CIGS WILL ARRIVE IN
CENTRAL OR SOUTH CENTRAL MOUNTAIN LOCATIONS THIS AFTERNOON.
EARLIER LOW LEVEL MOISTURE ACROSS THE SOUTH IS ALSO SLOWLY
DISSIPATING. RUC AND HRRR TIMING WAS A LITTLE LATE...BUT OVERALL
CORRECT IN ITS DISSIPATION.
ENS MEAN 850MB TEMPS ARND -6C LIKELY SUPPORTING HIGH TEMPS FROM
THE U30S ALLEGHENIES...TO THE M40S SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
RIDGE OF HIGH PRESSURE WILL BUILD SOUTH ACROSS PA TONIGHT...SUPPLYING
MCLEAR SKIES AND LIGHT WINDS. SWRLY FLOW AHEAD OF AN APPROACHING
COLD FRONT WILL DRAW A SURGE OF VERY MILD AIR INTO THE REGION
MONDAY. UNDER SUNNY SKIES...TEMPS SHOULD REACH 45-50F OVER MOST OF
CENTRAL PA. BUKKIT SOUNDINGS INDICATE SWRLY WIND GUSTS ARND
20KTS BY AFTN...ESP ACROSS THE NW MTNS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MDL DATA INDICATING A WEAK COLD FRONT WILL SAG SOUTH ACROSS PA
ON TUESDAY...POSSIBLY ACCOMPANIED BY A FEW -SHSN OVR THE N MTNS.
PATTERN FOR LATE WEEK CONTINUES TO LOOK DRY BUT PROGRESSIVELY
COOLER...AS SHORTWAVES CARVE OUT A DEEPENING TROUGH OVR THE
EASTERN CONUS. MDL CONSENSUS TRACKS FIRST SHORTWAVE THRU PA LATE
WED/EARLY THURS...POSSIBLY ACCOMPANIED BY SCT -SHSN. FCST
UNCERTAINTY RAMPS UP BY FRI/SAT...AS MDL SPREAD INCREASES WITH
RESPECT TO STRENGTH/TIMING OF NEXT SHORTWAVE. A BLEND OF GEFS AND
EC ENSEMBLES POINTS TOWARD A MAINLY DRY COLD FRONT PASSAGE ARND
FRIDAY...FOLLOWED BY A SEASONABLY COLD/DRY WEEKEND. THE STRONGER/SLOWER
00Z GFS SOLUTION...WITH POSSIBLE E COAST CYCLOGENESIS...APPEARS
AN UNLIKELY OUTLIER ATTM.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
LINGERING LIGHT RADAR RETURNS AT MID-LEVELS OVER SOUTHERN TIER
WILL CONTINUE TO DIMINISH BY MID MORNING AS DRY NORTHEASTERLY FLOW
FILTERS IN AT LOWER LEVELS - THE BEGINNING OF A RIDGE OF HIGH
PRESSURE BUILDING IN THAT WILL SETTLE ACROSS PA FOR THE NEXT
COUPLE OF DAYS.
AT 12Z...MVFR CONDITIONS AT KBFD IN LOWERING SUBSIDENCE INVERSION.
EXPECT A FAIRLY QUICK RETURN TO VFR CIGS BY MID-LATE MORNING.
KJST-KAOO ALSO EXPERIENCING MVFR-IFR CONDITIONS EARLY THIS MORNING
AS DRIER AIR HAS NOT HAD TIME TO WORK INTO THERE JUST YET. THERE
WILL LIKELY BE A SEVERAL HOUR PERIOD OF MVFR CONDITIONS THERE
BEFORE VFR CONDITIONS RETURN AROUND 16Z. ELSEWHERE...SOME PATCHY
MVFR FOG POSS THROUGH 14Z ACROSS THE SE.
BY AFTERNOON...VFR WILL BE THE RULE AS RIDGE STARTS TO DOMINATE.
EXPECT LIGHT WINDS AND PRISTINE FLYING CONDITIONS THROUGH AT
LEAST MONDAY NIGHT.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS WITH SHSN.
THU...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...DEVOIR/FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/MARTIN
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
742 AM EST SUN FEB 5 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE OVER THE GREAT LAKES WILL BUILD SOUTHEAST
ACROSS PENNSYLVANIA OVER THE NEXT COUPLE OF DAYS. A SERIES OF
SHORTWAVES WILL CARVE OUT A DEEPENING TROUGH ACROSS THE EASTERN
CONUS BY THE END OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WAVE OF LOW PRESSURE PASSING SOUTH OF PA CONTINUES TO PRODUCE
LIGHT RETURNS ON RADAR ACROSS THE S TIER. HOWEVER...SFC OBS
SUGGEST MOST OF THIS IS VIRGA...THE RESULT OF DRY NERLY FLOW AT
THE SFC. WILL CARRY A LOW CHC OF -SHSN ACROSS THE S TIER COUNTIES
UNTIL ABOUT 13Z.
PLENTY OF LOW LVL MOISTURE...COMBINED WITH CALM WIND...HAS ALLOWED
AREAS OF FOG TO FORM OVER SOUTHERN PA. RUC AND HRRR SFC RH SUGGEST
FOG ACROSS THE SC MTNS WILL DISSIPATE BY ARND 14Z. MUCH DRIER AIR
MASS ACROSS THE LOWER GRT LKS WILL OVERSPREAD THE REGION LATER
TODAY...BRINGING CLEARING SKIES. AIR MASS WILL REMAIN RELATIVELY
MILD FOR EARLY FEB WITH ENS MEAN 850MB TEMPS ARND -6C LIKELY
SUPPORTING HIGH TEMPS FROM THE U30S ALLEGHENIES...TO THE M40S SUSQ
VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
RIDGE OF HIGH PRESSURE WILL BUILD SOUTH ACROSS PA TONIGHT...SUPPLYING
MCLEAR SKIES AND LIGHT WINDS. SWRLY FLOW AHEAD OF AN APPROACHING
COLD FRONT WILL DRAW A SURGE OF VERY MILD AIR INTO THE REGION
MONDAY. UNDER SUNNY SKIES...TEMPS SHOULD REACH 45-50F OVER MOST OF
CENTRAL PA. BUKKIT SOUNDINGS INDICATE SWRLY WIND GUSTS ARND
20KTS BY AFTN...ESP ACROSS THE NW MTNS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MDL DATA INDICATING A WEAK COLD FRONT WILL SAG SOUTH ACROSS PA
ON TUESDAY...POSSIBLY ACCOMPANIED BY A FEW -SHSN OVR THE N MTNS.
PATTERN FOR LATE WEEK CONTINUES TO LOOK DRY BUT PROGRESSIVELY
COOLER...AS SHORTWAVES CARVE OUT A DEEPENING TROUGH OVR THE
EASTERN CONUS. MDL CONSENSUS TRACKS FIRST SHORTWAVE THRU PA LATE
WED/EARLY THURS...POSSIBLY ACCOMPANIED BY SCT -SHSN. FCST
UNCERTAINTY RAMPS UP BY FRI/SAT...AS MDL SPREAD INCREASES WITH
RESPECT TO STRENGTH/TIMING OF NEXT SHORTWAVE. A BLEND OF GEFS AND
EC ENSEMBLES POINTS TOWARD A MAINLY DRY COLD FRONT PASSAGE ARND
FRIDAY...FOLLOWED BY A SEASONABLY COLD/DRY WEEKEND. THE STRONGER/SLOWER
00Z GFS SOLUTION...WITH POSSIBLE E COAST CYCLOGENESIS...APPEARS
AN UNLIKELY OUTLIER ATTM.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
LINGERING LIGHT RADAR RETURNS AT MID-LEVELS OVER SOUTHERN TIER
WILL CONTINUE TO DIMINISH BY MID MORNING AS DRY NORTHEASTERLY FLOW
FILTERS IN AT LOWER LEVELS - THE BEGINNING OF A RIDGE OF HIGH
PRESSURE BUILDING IN THAT WILL SETTLE ACROSS PA FOR THE NEXT
COUPLE OF DAYS.
AT 12Z...MVFR CONDITIONS AT KBFD IN LOWERING SUBSIDENCE INVERSION.
EXPECT A FAIRLY QUICK RETURN TO VFR CIGS BY MID-LATE MORNING.
KJST-KAOO ALSO EXPERIENCING MVFR-IFR CONDITIONS EARLY THIS MORNING
AS DRIER AIR HAS NOT HAD TIME TO WORK INTO THERE JUST YET. THERE
WILL LIKELY BE A SEVERAL HOUR PERIOD OF MVFR CONDITIONS THERE
BEFORE VFR CONDITIONS RETURN AROUND 16Z. ELSEWHERE...SOME PATCHY
MVFR FOG POSS THROUGH 14Z ACROSS THE SE.
BY AFTERNOON...VFR WILL BE THE RULE AS RIDGE STARTS TO DOMINATE.
EXPECT LIGHT WINDS AND PRISTINE FLYING CONDITIONS THROUGH AT
LEAST MONDAY NIGHT.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS WITH SHSN.
THU...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/MARTIN
AVIATION...RXR
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
629 AM EST SUN FEB 5 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE OVER THE GREAT LAKES WILL BUILD SOUTHEAST
ACROSS PENNSYLVANIA OVER THE NEXT COUPLE OF DAYS. A SERIES OF
SHORTWAVES WILL CARVE OUT A DEEPENING TROUGH ACROSS THE EASTERN
CONUS BY THE END OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WAVE OF LOW PRESSURE PASSING SOUTH OF PA CONTINUES TO PRODUCE
LIGHT RETURNS ON RADAR ACROSS THE S TIER. HOWEVER...SFC OBS
SUGGEST MOST OF THIS IS VIRGA...THE RESULT OF DRY NERLY FLOW AT
THE SFC. WILL CARRY A LOW CHC OF -SHSN ACROSS THE S TIER COUNTIES
UNTIL ABOUT 13Z.
PLENTY OF LOW LVL MOISTURE...COMBINED WITH CALM WIND...HAS ALLOWED
AREAS OF FOG TO FORM OVER SOUTHERN PA. RUC AND HRRR SFC RH SUGGEST
FOG ACROSS THE SC MTNS WILL DISSIPATE BY ARND 14Z. MUCH DRIER AIR
MASS ACROSS THE LOWER GRT LKS WILL OVERSPREAD THE REGION LATER
TODAY...BRINGING CLEARING SKIES. AIR MASS WILL REMAIN RELATIVELY
MILD FOR EARLY FEB WITH ENS MEAN 850MB TEMPS ARND -6C LIKELY
SUPPORTING HIGH TEMPS FROM THE U30S ALLEGHENIES...TO THE M40S SUSQ
VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
RIDGE OF HIGH PRESSURE WILL BUILD SOUTH ACROSS PA TONIGHT...SUPPLYING
MCLEAR SKIES AND LIGHT WINDS. SWRLY FLOW AHEAD OF AN APPROACHING
COLD FRONT WILL DRAW A SURGE OF VERY MILD AIR INTO THE REGION
MONDAY. UNDER SUNNY SKIES...TEMPS SHOULD REACH 45-50F OVER MOST OF
CENTRAL PA. BUKKIT SOUNDINGS INDICATE SWRLY WIND GUSTS ARND
20KTS BY AFTN...ESP ACROSS THE NW MTNS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MDL DATA INDICATING A WEAK COLD FRONT WILL SAG SOUTH ACROSS PA
ON TUESDAY...POSSIBLY ACCOMPANIED BY A FEW -SHSN OVR THE N MTNS.
PATTERN FOR LATE WEEK CONTINUES TO LOOK DRY BUT PROGRESSIVELY
COOLER...AS SHORTWAVES CARVE OUT A DEEPENING TROUGH OVR THE
EASTERN CONUS. MDL CONSENSUS TRACKS FIRST SHORTWAVE THRU PA LATE
WED/EARLY THURS...POSSIBLY ACCOMPANIED BY SCT -SHSN. FCST
UNCERTAINTY RAMPS UP BY FRI/SAT...AS MDL SPREAD INCREASES WITH
RESPECT TO STRENGTH/TIMING OF NEXT SHORTWAVE. A BLEND OF GEFS AND
EC ENSEMBLES POINTS TOWARD A MAINLY DRY COLD FRONT PASSAGE ARND
FRIDAY...FOLLOWED BY A SEASONABLY COLD/DRY WEEKEND. THE STRONGER/SLOWER
00Z GFS SOLUTION...WITH POSSIBLE E COAST CYCLOGENESIS...APPEARS
AN UNLIKELY OUTLIER ATTM.
&&
.AVIATION /12Z SUNDAY THROUGH THURSDAY/...
BANDS OF LOW STRATOCU AND SNOW EMMINATING FROM LOW PRESSURE
TRACKING SOUTH OF PENNSYLVANIA WILL BRING LIFR TO VLIFR VSBYS AND
CIGS TO JST AND AOO THROUGH EARLY SUNDAY. AS THE LOW MOVES OFF TO
THE EAST DRYING WILL ARRIVE FROM NORTH TO SOUTH EARLY SUNDAY AS
HIGH PRESSURE BUILDS INTO THE REGION. VFR CONDS WILL RETURN WITH
FAIR WEATHER EXPECTED THROUGHOUT SUNDAY.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS. THU...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/MARTIN
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
537 AM EST SUN FEB 5 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE OVER THE GREAT LAKES WILL BUILD SOUTHEAST
ACROSS PENNSYLVANIA OVER THE NEXT COUPLE OF DAYS. A SERIES OF
SHORTWAVES WILL CARVE OUT A DEEPENING TROUGH ACROSS THE EASTERN
CONUS BY THE END OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WAVE OF LOW PRESSURE PASSING SOUTH OF PA CONTINUES TO PRODUCE
LIGHT RETURNS ON RADAR ACROSS THE S TIER. HOWEVER...SFC OBS
SUGGEST MOST OF THIS IS VIRGA...THE RESULT OF DRY NERLY FLOW AT
THE SFC. WILL CARRY A LOW CHC OF -SHSN ACROSS THE S TIER COUNTIES
UNTIL ABOUT 13Z.
PLENTY OF LOW LVL MOISTURE...COMBINED WITH CALM WIND...HAS ALLOWED
AREAS OF FOG TO FORM OVER SOUTHERN PA. RUC AND HRRR SFC RH SUGGEST
FOG ACROSS THE SC MTNS WILL DISSIPATE BY ARND 14Z. MUCH DRIER AIR
MASS...POISED ACROSS THE LOWER GRT LKS...WILL OVERSPREAD THE
REGION LATER TODAY...BRINGING CLEARING SKIES. AIR MASS WILL REMAIN
RELATIVELY MILD FOR EARLY FEB WITH ENS MEAN 850MB TEMPS ARND -6C
LIKELY SUPPORTING HIGH TEMPS FROM THE U30S ALLEGHENIES...TO THE
M40S SUSQ VALLEY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/...
RIDGE OF HIGH PRESSURE WILL BUILD SOUTH ACROSS PA TONIGHT...SUPPLYING
MCLEAR SKIES AND LIGHT WINDS. SWRLY FLOW AHEAD OF AN APPROACHING
COLD FRONT WILL DRAW A SURGE OF VERY MILD AIR INTO THE REGION
MONDAY. UNDER SUNNY SKIES...TEMPS SHOULD REACH 45-50F OVER MOST OF
CENTRAL PA. BUKKIT SOUNDINGS INDICATE SWRLY WIND GUSTS ARND
20KTS BY AFTN...ESP ACROSS THE NW MTNS.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
ALL MDL DATA INDICATING A WEAK COLD FRONT WILL SAG SOUTH ACROSS PA
ON TUESDAY...POSSIBLY ACCOMPANIED BY A FEW -SHSN OVR THE N MTNS.
PATTERN FOR LATE WEEK CONTINUES TO LOOK DRY BUT PROGRESSIVELY
COOLER...AS SHORTWAVES CARVE OUT A DEEPENING TROUGH OVR THE
EASTERN CONUS. MDL CONSENSUS TRACKS FIRST SHORTWAVE THRU PA LATE
WED/EARLY THURS...POSSIBLY ACCOMPANIED BY SCT -SHSN. FCST
UNCERTAINTY RAMPS UP BY FRI/SAT...AS MDL SPREAD INCREASES WITH
RESPECT TO STRENGTH/TIMING OF NEXT SHORTWAVE. A BLEND OF GEFS AND
EC ENSEMBLES POINTS TOWARD A MAINLY DRY COLD FRONT PASSAGE ARND
FRIDAY...FOLLOWED BY A SEASONABLY COLD/DRY WEEKEND. THE STRONGER/SLOWER
00Z GFS SOLUTION...WITH POSSIBLE E COAST CYCLOGENESIS...APPEARS
AN UNLIKELY OUTLIER ATTM.
&&
.AVIATION /10Z SUNDAY THROUGH THURSDAY/...
BANDS OF LOW STRATOCU AND SNOW EMMINATING FROM LOW PRESSURE
TRACKING SOUTH OF PENNSYLVANIA WILL BRING LIFR TO VLIFR VSBYS AND
CIGS TO JST AND AOO THROUGH EARLY SUNDAY. AS THE LOW MOVES OFF TO
THE EAST DRYING WILL ARRIVE FROM NORTH TO SOUTH EARLY SUNDAY AS
HIGH PRESSURE BUILDS INTO THE REGION. VFR CONDS WILL RETURN WITH
FAIR WEATHER EXPECTED THROUGHOUT SUNDAY.
OUTLOOK...
MON...NO SIG WX EXPECTED.
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS. THU...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD/MARTIN
AVIATION...DANGELO/CERU
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
957 AM CST SUN FEB 5 2012
.DISCUSSION...WIDESPREAD MODERATE RAIN FROM THIS MORNING HAS
PUSHED OFFSHORE. HOWEVER...ADDITIONAL LIGHT RAIN WITH EMBEDDED
MODERATE SHOWERS IS DEVELOPING UNDER THE RIGHT REAR QUAD OF AN
UPPER JET REMAINING OVER MEXICO AND WEST CENTRAL TEXAS. THE JET
WEAKENS AND SHIFTS TO THE EAST LATER TODAY WHICH SHOULD DECREASE
PRECIP CHANCES. ALTHOUGH LATEST GFS JUST COMING IN AS I TYPE THIS
SHOWS A BIT OF A JET STREAK OVER FAR EASTERN CWA OVERNIGHT...WHICH
COINCIDES WITH PRECIP INDICATED ON SOME MESO MODELS. WILL ANALYZE
MORE FOR AFTERNOON FORECAST PACKAGE. HAVE ALSO SEEN WINDS
BECOMING VERY GUSTY ALONG THE COASTAL BEND LATE THIS MORNING WITH
POSSIBLY A WEAK WAKE LOW DEVELOPING. MSAS 3HR PRESSURE CHANGE DID
INDICATE A BIT OF A MINIMUM NEAR BAFIN BAY THEN NORTHWARD TO
MATAGORDA BAY. MARGINAL WIND ADVISORY NOW IN EFFECT THROUGH NOON
FOR COASTAL COUNTIES. HAVE SEEK SEVERAL GUSTS IN THE 30 TO 40 MPH
RANGE WITH A GUST TO 46 MPH AT KNGP.
&&
.PREV DISCUSSION... /ISSUED 545 AM CST SUN FEB 5 2012/
DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...LARGE SHIELD OF PRECIPITATION WILL MOVE NORTHEAST
ACROSS SOUTH TEXAS THIS MORNING WITH A GRADUAL DECREASE FROM
WEST TO EAST AS THE UPPER LEVEL DISTURBANCE OVER NORTHERN
MEXICO MOVES NORTHEAST INTO CENTRAL TEXAS. MVFR CEILINGS/VSBYS
WILL BE PREVALENT THIS MORNING WITH PERIODIC IFR VSBYS IN THE
HEAVIER DOWNPOURS ASSOCIATED WITH EMBEDDED THUNDERSTORMS.
OVERCAST CONDITIONS WILL EXIST AS THE PRECIPITATION ACTIVITY
DIMINISHES LATE THIS AFTERNOON WITH CEILINGS RISING TO NEAR
5 KFT BRUSH COUNTRY...3500 FT FOR INLAND COASTAL PLAINS AND
CEILINGS REMAINING AROUND 3 KFT ALONG THE COAST THROUGH THE
NIGHT.
PREV DISCUSSION... /ISSUED 355 AM CST SUN FEB 5 2012/
SHORT TERM (TODAY)...LARGE SCALE ATMOSPHERIC LIFT INCREASED
LAST EVENING IN RESPONSE TO AN UPPER LEVEL JET STREAK THAT LIFTED
TO THE NORTH OF THE AREA. WIDESPREAD SHOWERS/SCATTERED THUNDERSTORMS
CONTINUE EARLY THIS MORNING WITH MORE TO COME. LARGE AREA OF
CONVECTION MOVING NORTHEAST FROM DEEP SOUTH TEXAS THIS MORNING.
WATER VAPOR IMAGERY SHOWS ANOTHER ENERGETIC UPPER LEVEL JET STREAK
LIFTING NORTH-NORTHEAST OUT OF MEXICO. LATEST RUC SHOWS A 90 KNOT
25H JET MOVING INTO COAHUILA THAT WILL MOVE INTO CENTRAL TEXAS
THIS AFTERNOON. SOUTH TEXAS WILL AGAIN BE IN A REGION OF INCREASING
LIFT IN RESPONSE TO INCREASING UPPER LEVEL DIVERGENCE. FORECAST
SOUNDINGS CONTINUE TO SHOW ELEVATED UNSTABLE LAYER ABOVE 800 MBS
REMAINING OVER THE REGION THROUGH THE DAY. GFS/ECMWF/NAM SHOW THE
85H TROUGH AXIS OVER THE BRUSH COUNTRY WITH THE GOOD MOISTURE FLUX
CONVERGENCE MOVING FROM THE BRUSH COUNTRY THROUGH THE COASTAL BEND
THROUGH THE DAY. TIME-HEIGHT CROSS SECTIONS SHOW LIFT THROUGH A
LARGE LAYER THROUGH THE MORNING INTO MID AFTERNOON. WILL GO WITH
CATEGORICAL POPS FOR MOST OF THE AREA EXCEPT WESTERN BRUSH COUNTRY
WHERE WENT WITH LIKELY POPS. QPF FORECAST WAS A BLEND OF THE
CMC/ECMWF/SREF WITH AVERAGE OF A LITTLE OVER HALF OF AN INCH ALONG
THE COAST...BUT THERE WILL BE AREAS THAT COULD RECEIVE UP TO AN
INCH. PRECIPITABLE WATER VALUES WILL BE ABOVE 1 INCH BRUSH COUNTRY
AND BE NEAR 1.5 INCHES OVER THE GULF WATERS.
MARINE (TODAY THROUGH TONIGHT)...HIGH PRESSURE BUILDING INTO THE
AREA WILL KEEP WINDS A BIT STRONGER AND REMAIN IN SCA RANGE FOR
A LITTLE LONGER. EXTENDED SCA FOR THE BAYS UNTIL 20Z AND FOR THE
GULF WATERS UNTIL 03Z MONDAY. WIDESPREAD SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE DAY WITH A DECREASE IN COVERAGE THIS
EVENING.
LONG TERM (TONIGHT THROUGH SATURDAY)...PRECIP EXPECTED TO DIMINISH
TONIGHT AS UPPER DISTURBANCE EXITS THE AREA. THE CANADIAN AND NAM
KEEP LIGHT PRECIP IN THE FCST ON MON...HOWEVER LEANED TOWARD THE
DRIER ECMWF AND GFS. MODELS CONTINUE TO PROG A SERIES OF EMBEDDED
SHORT WAVES TO TRACK ACROSS THE REGION THROUGH THE WEEK AHD OF A
POTENT CUT OFF LOW. MODELS DIFFER ON QPF EACH DAY AND THEY DIFFER ON
LOCATION OF HEAVIEST PRECIP. KEPT WITH THE CHC POPS DVLPG ACROSS THE
SRN CWA BY TUE NITE AND SHIFTING INTO THE WESTERN HALF OF THE CWA
THRU WED. THEN AS THE UPPER LOW MOVES ACROSS MEX TOWARD TX...UPPER
DIFFLUENCE INCREASES. THE HIGHEST PWATS ARE PROGD FOR THU AND LOW
LEVEL MOISTURE CONVERGENCE INCREASES AS A COLD FRONT/REINFORCING
HIGH PRESSURE PUSHES S INTO THE AREA. THEREFORE KEPT THE 50 POPS
ACROSS THE WEST DUE TO PROXIMITY TO UPPER LOW/BEST DYNAMICS. KEPT A
BROADBRUSHED 30 POP FOR FRI AS MODELS BEGIN TO DIVERGE ON
PLACEMENT/STRENGTH OF UPPER LOW AND CORRESPONDING PRECIP. GFS SHOWS
A DRIER FCST BY SAT AFTERNOON AS THE UPPER SYSTEM PUSHES THRU THE
AREA AND A NW FLOW ALOFT DVLPS. THE ECMWF IS A TAD SLOWER. WENT WITH
A BROADBRUSHED 20 POP ON SAT FOR NOW. AS FOR TEMPS...WENT WITH A
WARMING TREND MON THRU THU AHD OF COLD FRONT...THEN A SLIGHT COOLING
TREND FRI AND SAT IN THE WAKE OF THE COLD FRONT. OVERALL TEMPS ARE
PROGD TO BE GENERALLY BELOW NORMAL THROUGH THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 50 44 60 45 65 / 80 40 10 10 20
VICTORIA 50 41 58 42 64 / 80 20 10 10 20
LAREDO 54 46 61 46 66 / 60 10 10 10 10
ALICE 51 43 59 42 65 / 80 30 10 10 20
ROCKPORT 51 46 60 49 66 / 80 40 10 10 20
COTULLA 52 41 59 42 64 / 70 10 10 10 10
KINGSVILLE 50 43 59 44 66 / 80 40 10 10 20
NAVY CORPUS 52 46 60 48 67 / 80 40 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR.
&&
$$
PZ/83...SHORT TERM
TE/81...LONG TERM
AREA FORECAST DISCUSSION...UPDATED
NWS CORPUS CHRISTI TX
545 AM CST SUN FEB 5 2012
.DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
&&
.AVIATION...LARGE SHIELD OF PRECIPITATION WILL MOVE NORTHEAST
ACROSS SOUTH TEXAS THIS MORNING WITH A GRADUAL DECREASE FROM
WEST TO EAST AS THE UPPER LEVEL DISTURBANCE OVER NORTHERN
MEXICO MOVES NORTHEAST INTO CENTRAL TEXAS. MVFR CEILINGS/VSBYS
WILL BE PREVALENT THIS MORNING WITH PERIODIC IFR VSBYS IN THE
HEAVIER DOWNPOURS ASSOCIATED WITH EMBEDDED THUNDERSTORMS.
OVERCAST CONDITIONS WILL EXIST AS THE PRECIPITATION ACTIVITY
DIMINISHES LATE THIS AFTERNOON WITH CEILINGS RISING TO NEAR
5 KFT BRUSH COUNTRY...3500 FT FOR INLAND COASTAL PLAINS AND
CEILINGS REMAINING AROUND 3 KFT ALONG THE COAST THROUGH THE
NIGHT.
&&
.PREV DISCUSSION... /ISSUED 355 AM CST SUN FEB 5 2012/
SHORT TERM (TODAY)...LARGE SCALE ATMOSPHERIC LIFT INCREASED
LAST EVENING IN RESPONSE TO AN UPPER LEVEL JET STREAK THAT LIFTED
TO THE NORTH OF THE AREA. WIDESPREAD SHOWERS/SCATTERED THUNDERSTORMS
CONTINUE EARLY THIS MORNING WITH MORE TO COME. LARGE AREA OF
CONVECTION MOVING NORTHEAST FROM DEEP SOUTH TEXAS THIS MORNING.
WATER VAPOR IMAGERY SHOWS ANOTHER ENERGETIC UPPER LEVEL JET STREAK
LIFTING NORTH-NORTHEAST OUT OF MEXICO. LATEST RUC SHOWS A 90 KNOT
25H JET MOVING INTO COAHUILA THAT WILL MOVE INTO CENTRAL TEXAS
THIS AFTERNOON. SOUTH TEXAS WILL AGAIN BE IN A REGION OF INCREASING
LIFT IN RESPONSE TO INCREASING UPPER LEVEL DIVERGENCE. FORECAST
SOUNDINGS CONTINUE TO SHOW ELEVATED UNSTABLE LAYER ABOVE 800 MBS
REMAINING OVER THE REGION THROUGH THE DAY. GFS/ECMWF/NAM SHOW THE
85H TROUGH AXIS OVER THE BRUSH COUNTRY WITH THE GOOD MOISTURE FLUX
CONVERGENCE MOVING FROM THE BRUSH COUNTRY THROUGH THE COASTAL BEND
THROUGH THE DAY. TIME-HEIGHT CROSS SECTIONS SHOW LIFT THROUGH A
LARGE LAYER THROUGH THE MORNING INTO MID AFTERNOON. WILL GO WITH
CATEGORICAL POPS FOR MOST OF THE AREA EXCEPT WESTERN BRUSH COUNTRY
WHERE WENT WITH LIKELY POPS. QPF FORECAST WAS A BLEND OF THE
CMC/ECMWF/SREF WITH AVERAGE OF A LITTLE OVER HALF OF AN INCH ALONG
THE COAST...BUT THERE WILL BE AREAS THAT COULD RECEIVE UP TO AN
INCH. PRECIPITABLE WATER VALUES WILL BE ABOVE 1 INCH BRUSH COUNTRY
AND BE NEAR 1.5 INCHES OVER THE GULF WATERS.
MARINE (TODAY THROUGH TONIGHT)...HIGH PRESSURE BUILDING INTO THE
AREA WILL KEEP WINDS A BIT STRONGER AND REMAIN IN SCA RANGE FOR
A LITTLE LONGER. EXTENDED SCA FOR THE BAYS UNTIL 20Z AND FOR THE
GULF WATERS UNTIL 03Z MONDAY. WIDESPREAD SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE DAY WITH A DECREASE IN COVERAGE THIS
EVENING.
LONG TERM (TONIGHT THROUGH SATURDAY)...PRECIP EXPECTED TO DIMINISH
TONIGHT AS UPPER DISTURBANCE EXITS THE AREA. THE CANADIAN AND NAM
KEEP LIGHT PRECIP IN THE FCST ON MON...HOWEVER LEANED TOWARD THE
DRIER ECMWF AND GFS. MODELS CONTINUE TO PROG A SERIES OF EMBEDDED
SHORT WAVES TO TRACK ACROSS THE REGION THROUGH THE WEEK AHD OF A
POTENT CUT OFF LOW. MODELS DIFFER ON QPF EACH DAY AND THEY DIFFER ON
LOCATION OF HEAVIEST PRECIP. KEPT WITH THE CHC POPS DVLPG ACROSS THE
SRN CWA BY TUE NITE AND SHIFTING INTO THE WESTERN HALF OF THE CWA
THRU WED. THEN AS THE UPPER LOW MOVES ACROSS MEX TOWARD TX...UPPER
DIFFLUENCE INCREASES. THE HIGHEST PWATS ARE PROGD FOR THU AND LOW
LEVEL MOISTURE CONVERGENCE INCREASES AS A COLD FRONT/REINFORCING
HIGH PRESSURE PUSHES S INTO THE AREA. THEREFORE KEPT THE 50 POPS
ACROSS THE WEST DUE TO PROXIMITY TO UPPER LOW/BEST DYNAMICS. KEPT A
BROADBRUSHED 30 POP FOR FRI AS MODELS BEGIN TO DIVERGE ON
PLACEMENT/STRENGTH OF UPPER LOW AND CORRESPONDING PRECIP. GFS SHOWS
A DRIER FCST BY SAT AFTERNOON AS THE UPPER SYSTEM PUSHES THRU THE
AREA AND A NW FLOW ALOFT DVLPS. THE ECMWF IS A TAD SLOWER. WENT WITH
A BROADBRUSHED 20 POP ON SAT FOR NOW. AS FOR TEMPS...WENT WITH A
WARMING TREND MON THRU THU AHD OF COLD FRONT...THEN A SLIGHT COOLING
TREND FRI AND SAT IN THE WAKE OF THE COLD FRONT. OVERALL TEMPS ARE
PROGD TO BE GENERALLY BELOW NORMAL THROUGH THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 50 44 60 45 65 / 80 40 10 10 20
VICTORIA 50 41 58 42 64 / 80 20 10 10 20
LAREDO 54 46 61 46 66 / 60 10 10 10 10
ALICE 51 43 59 42 65 / 80 30 10 10 20
ROCKPORT 51 46 60 49 66 / 80 40 10 10 20
COTULLA 52 41 59 42 64 / 70 10 10 10 10
KINGSVILLE 50 43 59 44 66 / 80 40 10 10 20
NAVY CORPUS 52 46 60 48 67 / 80 40 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR.
&&
$$
TMT/89...SHORT TERM/AVIATION
TE/81...LONG TERM
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
534 AM CST SUN FEB 5 2012
UPDATED AVIATION PORTION FOR 12Z TAF ISSUANCE
.SHORT TERM...TODAY THROUGH MONDAY...CLOUD TRENDS ARE THE MAIN FCST
CONCERN.
A S/W TROF BRUSHING PAST TO OUR NE HAS HELPED TO PUSH A WEAK COLD
FRONT THROUGH THE REGION. LOW CLOUDS HAVE INVADED THE NORTHERN
AND EASTERN PARTS OF CWAIN THE WAKE OF THE FRONT...BUT WERE HAVING
A HARD TIME SPREADING INTO CENTRAL WI. A LARGE EXPANSE OF VERY LOW
STRATUS AND FOG WAS ALSO SITUATED OVER MN...AND WAS STARTING TO
CROSS THE WI BORDER.
LOW-LEVEL WINDS ARE EXPECTED TO BECOME WESTERLY BY THIS AFTERNOON...
WHICH SHOULD PUSH THE CURRENT BATCH OF LOW CLOUDS OUT OF GRB CWA.
THIS IS DEPICTED FAIRLY WELL BY THE RUC MODEL. BIG QUESTION IS
WHETHER THE STRATUS OVER MN WILL MAKE A RUN AT THE FORECAST AREA
LATER TODAY INTO TONIGHT. MODELS DO NOT HAVE GOOD HANDLE ON THIS
SCENARIO...AND DON`T OFFER MUCH ASSISTANCE WITH THIS ASPECT OF THE
FCST. WOULD TEND TO BELIEVE THAT THE EASTERN EDGE OF THIS CLOUD
DECK WOULD ERODE DUE TO DAYTIME MIXING...BUT LIKELY REFORM TONIGHT...
AND EDGE INTO NC/C WI. STIFF WESTERLY DOWNSLOPE WINDS (25-30 KTS
AT 925 MB) SHOULD PREVENT THE STRATUS FROM REACHING NE/EC WI.
BASED ON LOW CONFIDENCE...WILL ONLY MENTION PARTLY CLOUDY SKIES
FOR NC/C WI TONIGHT.
A COLD FRONT IS EXPECTED TO SWEEP SOUTHEAST ACROSS THE FORECAST
AREA ON MONDAY...WITH ANOTHER SURGE OF LOW CLOUDS DROPPING INTO
NC/NE WI DURING THE AFTERNOON. NORTH FLOW OFF LAKE SUPERIOR MAY
LEAD TO SOME FLURRIES OR FREEZING DRIZZLE OVER FAR NORTHERN WI
LATE IN THE DAY.
USED A BLEND OF VARIOUS GUIDANCE SETS FOR TEMPERATURES...WHICH
WILL REMAIN WELL ABOVE NORMAL THROUGH MONDAY. THE COLD FRONT WILL
BRING A RETURN TO MORE NORMAL TEMPERATURES BY MONDAY NIGHT/TUESDAY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
MEAN UPPER LEVEL FLOW ACROSS THE REGION SHOULD BE FROM THE
NORTHWEST WITH THE HIGH AMPLITUDE RIDGE WEST OF THE ROCKIES.
PRECIPITATION DURING THE PERIOD SHOULD BE MAINLY FROM LAKE EFFECT
DUE TO LACK OF SIGNIFICANT MOISTURE WITH SYSTEMS MOVING ACROSS THE
UPPER GREAT LAKES REGION. COLDER AIR WILL MAKE ITS WAY INTO THE
REGION BUT TEMPERATURES SHOULD NOT BE MUCH BELOW NORMAL...EVEN ON
THE COLDEST NIGHTS AND DAYS.
HAVE A CHANCE OF SNOW SHOWERS NEAR THE UPPER MICHIGAN BORDER ON
MONDAY NIGHT IN COLD ADVECTION BEHIND A SURFACE COLD FRONT WITH AN
ASSIST FROM A PASSING UPPER LEVEL TROUGH. THIS SHOULD COME TO AN
END EARLY ON TUESDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE
REGION. EXPECT LOWS TO BE NEAR OR A BIT BELOW NORMAL ON TUESDAY
NIGHT WITH THE SURFACE HIGH AND UPPER LEVEL RIDGE OVER THE AREA.
RETURN FLOW AND PLENTY OF SUNSHINE ON WEDNESDAY SHOULD ALLOW
TEMPERATURES TO RISE ABOVE NORMAL ONCE AGAIN...UNTIL ANOTHER SHOT
OF COLDER AIR IMPACTS THE FORECAST AREA BEHIND THE NEXT COLD
FRONT MOVING THROUGH ON THURSDAY. EXPECT BELOW NORMAL TEMPERATURES
ON FRIDAY AND SATURDAY. HAVE LOW END CHANCE OR HIGH END SLIGHT
CHANCE POPS GOING FOR NORTH CENTRAL WISCONSIN AND THE LAKESHORE AT
TIMES THROUGH THE END OF THE FORECAST PERIOD DUE TO POSSIBLE LAKE
EFFECT SNOW SHOWERS.
&&
.AVIATION...MVFR/IFR CIGS HAVE PUSHED INTO NORTHERN AND EASTERN WI
EARLY THIS MORNING. SOME PATCHY FOG HAD DEVELOPED IN CENTRAL WI...
WHERE SKIES WERE STILL CLEAR. EXPECT THE STRATUS TO EVENTUALLY
PULL OUT TO THE EAST BY LATE MORNING OR EARLY AFTERNOON...AS LOW-
LEVEL WINDS BECOME WESTERLY. HOWEVER...WIDESPREAD IFR/LIFR CIGS
OVER MN AND FAR WSTRN WI COULD MAKE A RUN AT NC/C WI LATER TODAY
INTO TONIGHT. CONFIDENCE IS LOW IN HOW THIS WILL PLAY OUT...SO
WILL JUST MENTION SCT LOW CLOUDS AT RHI/AUW/CWA TONIGHT.
DOWNSLOPING WEST WINDS SHOULD KEEP THE LOW CLOUDS FROM FORMING
OVER NE/EC WI TONIGHT. WEST-NORTHWEST WINDS INCREASING TO 35 KTS
AT 1000-1500 FT AGL WILL RESULT IN SOME LLWS...STARTING THIS EVG.
KIECKBUSCH
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
528 AM CST SUN FEB 5 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY
249 AM CST SUN FEB 5 2012
ANOTHER DAY OF TRYING TO FORECAST STRATUS AND TEMPERATURES IS ON
DECK FOR TODAY FOLLOWED BY A COLD FRONT THAT WILL COME THROUGH
MONDAY NIGHT.
ODDLY SITUATED MID LEVEL PATTERN IN PLACE WITH A TROUGH AND TWO
EMBEDDED VORT MAXES EXTENDING WEST FROM THE EASTERN GREAT LAKES
TOWARD NEVADA WITH A CUT OFF RIDGE SET UP ALONG THE US/CANADA
BORDER FROM THE PACIFIC NORTHWEST GOING EAST TOWARD THE DAKOTAS.
AT THE SURFACE...A BROAD RIDGE OF HIGH PRESSURE IS IN PLACE ALONG
THE EASTERN ROCKIES/WESTERN PLAINS WITH A RIDGE AXIS EXTENDING EAST
THROUGH THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES REGION.
TWO MAIN POCKETS OF STRATUS REMAIN TRAPPED UNDER THE 950-900MB
INVERSION WITH ONE ADVANCING SOUTH-SOUTHEAST ACROSS MINNESOTA AND
ANOTHER OVER THE UPPER PENINSULA OF MICHIGAN AND NORTHEAST
WISCONSIN ADVANCING SOUTH-SOUTHWEST ACROSS EASTERN WISCONSIN.
WHAT HAPPENS WITH THIS CLOUD DECK TODAY IS THE MAIN QUESTION SINCE
IT WILL HAVE A DIRECT IMPACT ON HOW HIGH TEMPERATURES GET ONCE
AGAIN. BASED ON THE 05.06Z HRRR AND RECENT IR SATELLITE
TRENDS...IT LOOKS LIKE THE MINNESOTA STRATUS WILL HOLD ON THROUGH
THE MORNING ACROSS MN/IA WITH THE WISCONSIN STRATUS REACHING THE
MISSISSIPPI RIVER BY LATE MORNING. WHILE SOME HOLES WILL LIKELY
FORM THROUGH THE DAY...WENT A BIT ON THE PESSIMISTIC SIDE FOR
CLOUD COVER TODAY WHICH IN TURN WILL KEEP TEMPERATURES DOWN.
WHERE THE HOLES DO OPEN UP TODAY...HIGHS WILL LIKELY END UP IN THE
LOW TO MID 40S WITH TEMPERATURES IN THE 30S UNDER THE CLOUD DECK.
SOME INCREASING WESTERLY WINDS WILL PUSH DOWN ACROSS NORTHERN
WISCONSIN TODAY AND TONIGHT AND MAY HELP TO MIX OUT SOME OF THIS
LOW STRATUS AND CLEAR SKIES FROM THE NORTH.
THE FOCUS THEN GOES TO A COLD FRONT THAT WILL DROP THROUGH THE
REGION ON MONDAY NIGHT. AHEAD OF IT...WARM AIR ADVECTION AND
INCREASED LOW LEVEL MIXING WILL LEAD TO SUNNY SKIES AND A MILD DAY
WITH HIGHS LIKELY TO REACH THE MID TO UPPER 40S. THE TIMING OF THE
COLD FRONT PASSAGE MONDAY AFTERNOON AND NIGHT IS PRETTY CONSISTENT
BETWEEN THE 05.00Z MODEL SOLUTIONS WITH THE FRONT GETTING SOUTH
OF LA CROSSE AND ROCHESTER BEFORE 00Z TUESDAY AND SOUTH OF THE
WISCONSIN STATE LINE BY 06Z. LOW LEVEL CLOUD COVER WILL BE ON THE
INCREASE AS THE FRONT PASSES WITH THE QUESTION NOW BEING WHETHER
ANY FLURRIES WILL BE POSSIBLE AS THIS FEATURE PASSES. 05.00Z
NAM/GFS SOUNDINGS ARE TRENDING TOWARD HAVING A DEEPER LOW LEVEL
MIXED TEMPERATURE PROFILE WITH A DECENT AMOUNT OF MOISTURE AND
LIFT IN THIS LAYER AVAILABLE TO POSSIBLY PRODUCE SOME SNOWFLAKES
AS THE LAYER COOLS TOWARD -10/-12C. CONFIDENCE IS NOT THAT HIGH AT
THIS POINT TO PUT THESE POSSIBLE FLURRIES IN THE FORECAST...BUT IT
IS AT LEAST SOMETHING TO KEEP TABS ON OVER THE NEXT FEW DAYS.
A BROAD RIDGE OF HIGH PRESSURE WILL MOVE INTO THE UPPER
MISSISSIPPI RIVER VALLEY TUESDAY INTO WEDNESDAY AND WILL KEEP
TEMPERATURES DOWN TOWARD NORMAL INTO MID WEEK.
.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY
249 AM CST SUN FEB 5 2012
FOCUS IN THE EXTENDED CONTINUES TO BE WITH A COLD FRONT THAT IS
PROGGED TO COME THROUGH LATER IN THE WEEK. THE 05.00Z GFS
CONTINUES ITS TREND OF BEING THE FASTEST WITH THIS FEATURE AND
BRINGS IT THROUGH EARLY ON THURSDAY WHILE THE 05.00Z ECMWF IS
STILL SLOWER AND DOES NOT DROP THE FRONT THROUGH UNTIL FRIDAY.
INTRODUCED SOME LIGHT SNOW CHANCES ACROSS NORTH CENTRAL WISCONSIN
WITH THIS FEATURE AS THE GFS HAS BEEN SHOWING SOME POSSIBLE QPF UP
THERE THE PAST FEW RUNS.
OTHERWISE DIFFERENCES CROP UP GOING INTO THE WEEKEND WITH HOW LONG
THE COLD LOW LEVEL AIR REMAINS IN PLACE WITH THE 05.00Z GFS NOW
HOLDING ONTO 850MB TEMPERATURES BELOW -20C INTO THE WEEKEND WHILE
THE 05.00Z ECMWF PUSHING THE COLD AIR RAPIDLY OFF TO THE EAST LOW
LEVEL WARM AIR ADVECTION KICKING IN BY SATURDAY. GIVEN THESE
DISCREPANCIES...CONFIDENCE IS NOT ALL THAT HIGH IN HOW
TEMPERATURES WILL END UP TOWARD THE LATER PORTION OF THE FORECAST
PACKAGE.
&&
.AVIATION...TODAY AND TONIGHT
527 AM CST SUN FEB 5 2012
LOW STRATUS WILL PRODUCE LIFR CONDITIONS AT KRST AND IFR
CONDITIONS AT KLSE THROUGH MUCH OF THIS MORNING. PLAN ON CLOUD
BASES AROUND 400 FT AT KRST AND 900 FT AT KLSE. IN
ADDITION...VISIBILITIES WILL RANGE FROM 3 TO 5 SM IN BR. LOOK FOR
CONDITIONS TO GRADUALLY IMPROVE TO VFR THIS AFTERNOON AS THE
SURFACE RIDGE SLIDES SOUTH OF THE REGION AND THE PRESSURE GRADIENT
TIGHTENS AHEAD OF AN APPROACHING COLD FRONT ACROSS SOUTHERN
MANITOBA/ONTARIO. LOOK FOR WINDS TO BACK TO THE WEST/SOUTHWEST
TONIGHT...WITH SPEEDS OF 6 TO 10 KTS EXPECTED. GUIDANCE IS
SUGGESTING AREAS OF BR TONIGHT AT KRST. THIS SEEMS REASONABLE
GIVEN THE AIRMASS IN PLACE...SO HAVE DECIDED TO MAINTAIN 5 SM BR
IN THE FORECAST THIS EVENING...STARTING AT 04Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
249 AM CST SUN FEB 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
404 AM CST SUN FEB 5 2012
.SHORT TERM...TODAY THROUGH MONDAY...CLOUD TRENDS ARE THE MAIN FCST
CONCERN.
A S/W TROF BRUSHING PAST TO OUR NE HAS HELPED TO PUSH A WEAK COLD
FRONT THROUGH THE REGION. LOW CLOUDS HAVE INVADED THE NORTHERN
AND EASTERN PARTS OF CWAIN THE WAKE OF THE FRONT...BUT WERE HAVING
A HARD TIME SPREADING INTO CENTRAL WI. A LARGE EXPANSE OF VERY LOW
STRATUS AND FOG WAS ALSO SITUATED OVER MN...AND WAS STARTING TO
CROSS THE WI BORDER.
LOW-LEVEL WINDS ARE EXPECTED TO BECOME WESTERLY BY THIS AFTERNOON...
WHICH SHOULD PUSH THE CURRENT BATCH OF LOW CLOUDS OUT OF GRB CWA.
THIS IS DEPICTED FAIRLY WELL BY THE RUC MODEL. BIG QUESTION IS
WHETHER THE STRATUS OVER MN WILL MAKE A RUN AT THE FORECAST AREA
LATER TODAY INTO TONIGHT. MODELS DO NOT HAVE GOOD HANDLE ON THIS
SCENARIO...AND DON`T OFFER MUCH ASSISTANCE WITH THIS ASPECT OF THE
FCST. WOULD TEND TO BELIEVE THAT THE EASTERN EDGE OF THIS CLOUD
DECK WOULD ERODE DUE TO DAYTIME MIXING...BUT LIKELY REFORM TONIGHT...
AND EDGE INTO NC/C WI. STIFF WESTERLY DOWNSLOPE WINDS (25-30 KTS
AT 925 MB) SHOULD PREVENT THE STRATUS FROM REACHING NE/EC WI.
BASED ON LOW CONFIDENCE...WILL ONLY MENTION PARTLY CLOUDY SKIES
FOR NC/C WI TONIGHT.
A COLD FRONT IS EXPECTED TO SWEEP SOUTHEAST ACROSS THE FORECAST
AREA ON MONDAY...WITH ANOTHER SURGE OF LOW CLOUDS DROPPING INTO
NC/NE WI DURING THE AFTERNOON. NORTH FLOW OFF LAKE SUPERIOR MAY
LEAD TO SOME FLURRIES OR FREEZING DRIZZLE OVER FAR NORTHERN WI
LATE IN THE DAY.
USED A BLEND OF VARIOUS GUIDANCE SETS FOR TEMPERATURES...WHICH
WILL REMAIN WELL ABOVE NORMAL THROUGH MONDAY. THE COLD FRONT WILL
BRING A RETURN TO MORE NORMAL TEMPERATURES BY MONDAY NIGHT/TUESDAY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
MEAN UPPER LEVEL FLOW ACROSS THE REGION SHOULD BE FROM THE
NORTHWEST WITH THE HIGH AMPLITUDE RIDGE WEST OF THE ROCKIES.
PRECIPITATION DURING THE PERIOD SHOULD BE MAINLY FROM LAKE EFFECT
DUE TO LACK OF SIGNIFICANT MOISTURE WITH SYSTEMS MOVING ACROSS THE
UPPER GREAT LAKES REGION. COLDER AIR WILL MAKE ITS WAY INTO THE
REGION BUT TEMPERATURES SHOULD NOT BE MUCH BELOW NORMAL...EVEN ON
THE COLDEST NIGHTS AND DAYS.
HAVE A CHANCE OF SNOW SHOWERS NEAR THE UPPER MICHIGAN BORDER ON
MONDAY NIGHT IN COLD ADVECTION BEHIND A SURFACE COLD FRONT WITH AN
ASSIST FROM A PASSING UPPER LEVEL TROUGH. THIS SHOULD COME TO AN
END EARLY ON TUESDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE
REGION. EXPECT LOWS TO BE NEAR OR A BIT BELOW NORMAL ON TUESDAY
NIGHT WITH THE SURFACE HIGH AND UPPER LEVEL RIDGE OVER THE AREA.
RETURN FLOW AND PLENTY OF SUNSHINE ON WEDNESDAY SHOULD ALLOW
TEMPERATURES TO RISE ABOVE NORMAL ONCE AGAIN...UNTIL ANOTHER SHOT
OF COLDER AIR IMPACTS THE FORECAST AREA BEHIND THE NEXT COLD
FRONT MOVING THROUGH ON THURSDAY. EXPECT BELOW NORMAL TEMPERATURES
ON FRIDAY AND SATURDAY. HAVE LOW END CHANCE OR HIGH END SLIGHT
CHANCE POPS GOING FOR NORTH CENTRAL WISCONSIN AND THE LAKESHORE AT
TIMES THROUGH THE END OF THE FORECAST PERIOD DUE TO POSSIBLE LAKE
EFFECT SNOW SHOWERS.
&&
.AVIATION...MVFR/IFR CIGS HAVE PUSHED INTO NORTHERN AND EASTERN WI
EARLY THIS MORNING. SOME PATCHY FOG JUST STARTING TO DEVELOP IN CENTRAL
WI...WHERE SKIES ARE STILL CLEAR. EXPECT THE STRATUS TO EVENTUALLY
PULL OUT TO THE EAST BY MIDDAY OR EARLY AFTERNOON...AS LOW-LEVEL
WINDS BECOME WESTERLY. HOWEVER...WIDESPREAD IFR/LIFR CIGS OVER MN
AND FAR WSTRN WI COULD MAKE A RUN AT NC/C WI LATER TODAY INTO
TONIGHT. CONFIDENCE IS LOW IN HOW THIS WILL PLAY OUT.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
KIECKBUSCH/MG
AREA FORECAST DISCUSSION
NWS GRAND JUNCTION CO
1024 AM MST SUN FEB 5 2012
.SHORT TERM /REST OF TODAY THROUGH MONDAY NIGHT/...
QUICK UPDATE TO INCREASE POPS ACROSS THE SOUTHWEST SAN
JUANS AND ADJACENT SOUTHERN VALLEYS WHERE SCATTERED SNOW SHOWERS
CONTINUE. ACCUMULATIONS WILL BE ON THE LIGHT SIDE...BUT WEBCAMS
INDICATING SOME IMPACT ON ROAD SURFACES. LATEST RUC SUGGESTS THIS
ACTIVITY WILL CONTINUE FOR A FEW MORE HOURS IN SHALLOW UPSLOPE
FLOW INTO THE SAN JUANS.
CUT-OFF UPPER LOW WAS FORMING OVER WRN UT EARLY THIS MORNING IN AN
ELONGATED AREA OF LOW PRESSURE THAT STRETCHED FROM NV TO KS. THIS
UPPER LOW WILL STAY OVER UT THROUGH TONIGHT...WHEN A SHORTWAVE
DROPPING OUT OF CENTRAL CANADA AND A PACIFIC TROUGH REACHING THE
COAST FINALLY BEGIN TO PULL/PUSH IT EASTWARD ACROSS COLORADO ON
MONDAY-MONDAY NIGHT. THIS WILL KEEP AREAS OF CLOUDS AND A CHANCE OF
SNOW SHOWERS PRESENT THROUGH MONDAY NIGHT...AND MODELS ARE IN GOOD
AGREEMENT ON THIS SCENARIO. EMBEDDED DISTURBANCES ROTATING
COUNTERCLOCKWISE AROUND THE LOW WILL CROSS SE UT/SW CO AND FOCUS THE
CHANCE OF PRECIP MOSTLY ACROSS THE SOUTH HALF OF OUR FORECAST AREA.
THE BEST CHANCE LOOKS TO BE SUNDAY NIGHT AND MONDAY WHEN PERHAPS THE
MOST ENERGETIC DISTURBANCE PASSES. MOISTURE SHOULD BE LIMITED AS
THERE IS NO MOISTURE TAP TO THIS SYSTEM...BUT TEMPERATURES ALOFT
WILL BE NEAR OR IN THE FAVORABLE REGIME FOR SNOW CRYSTAL
GROWTH...AND SNOW SHOWERS COULD PRODUCE LOCALIZED ACCUMULATIONS OF A
COUPLE INCHES OVER THE SOUTHERN AND CENTRAL MOUNTAINS. SNOW CHANCES
WILL BE ON THE DECREASE MONDAY NIGHT AS THE LOW MOVES BY.
TEMPERATURES LOOK TO RUN NEAR PERSISTENCE TO A FEW DEGREES COOLER.
.LONG TERM /TUESDAY THROUGH SATURDAY/...
GOOD AGREEMENT BETWEEN THE MEDIUM RANGE MODELS THROUGH THE ENTIRE
LONG TERM PERIOD. STRONG PACIFIC WAVE BREAKS OFF FROM THE MAIN
WESTERLIES AND DIVES SOUTHEAST ALONG THE CALIFORNIA AND BAJA
COAST ON WEDNESDAY AND THURSDAY...MISSING OUR FORECAST AREA ALTHOUGH
SOUTHEAST UTAH MAY SEE AN INCREASE OF CLOUDS. BUT THERE ARE SOME
SUBTLE DIFFERENCES THAT DOES HAVE SMALL IMPLICATIONS FOR OUR FORECAST
AREA. THE GFS SHOWS SOME SPOTTY LIGHT PCPN WITH A WEAK SHORT WAVE
BRUSHING NW COLORADO ON WEDNESDAY AFTERNOON AND EVENING. THE
LATEST ECMWF SHOW A SIMILAR SOLUTION BUT THE SPOTTY PCPN OCCURS THE
NEXT DAY. THE CANADIAN MODEL SHOWS STRONGER PACIFIC ENERGY
UNDERCUTTING THE STRONG AMPLIFIED RIDGE OVER WRN CANADA. NONE OF
THESE SOLUTIONS CAN BE CONSIDERED A SIGNIFICANT EVENT...BUT
SUGGEST THAT THE UPCOMING WEEK MAY NOT BE COMPLETELY DRY. RUN TO RUN
MODEL CONSISTENCY CAN BE BETTER AND BELIEVE THAT FUTURE MODEL
SOLUTIONS WILL OFFER MORE DIFFERENCES. EXTENDED GUIDANCE POPS
STAY BELOW 15 PERCENT AND WILL NOT DEVIATE FROM THIS AT THIS
TIME...ESSENTIALLY KEEPING THE GOING FORECAST DRY THROUGH DAYS 3
THROUGH 7. CONFIDENCE IS SO-SO AND IF MODELS SHOW SOME CONSISTENCY
WITH THE PASSING SHORT WAVE WEDNESDAY NIGHT AND THURSDAY TIME
FRAME...THEN CHANCE POPS FOR NW COLORADO WILL NEED TO BE
INTRODUCED.
&&
.AVIATION /FOR 18Z TAF ISSUANCE/...
AN UPPER LOW SPINS OVER EASTERN UTAH TODAY AND TONIGHT. WEAK LIFT
ASSOCIATED WITH THE LOW WILL COMBINE WITH A MOIST LAYER BETWEEN
10000 AND 14000FT MSL OVER THE REGION TO PRODUCE SCATTERED
MOUNTAIN SNOW SHOWERS. MORE WIDESPREAD SHOWERS ARE POSSIBLE OVER
THE SOUTHERN MTNS. MTN TOPS WILL BE OCNLY OBSCURED.
THE CHANCES FOR LESS THAN VFR CONDITIONS IS 30 PERCENT AT KASE
KMTJ KDRO KCEZ...WHILE KTEX WILL BE 50 PERCENT.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&
$$
SHORT TERM...JDC/JAD
LONG TERM....PF
AVIATION.....JOE
AREA FORECAST DISCUSSION
NWS LINCOLN IL
230 PM CST SUN FEB 5 2012
.DISCUSSION...
ISSUED 230 PM CST SUN FEB 5 2012
HIGH PRESSURE CONTINUES TO BUILD INTO CENTRAL AND SOUTHEAST
ILLINOIS THIS AFTERNOON...AND IS HELPING TO PROVIDE A MOSTLY SUNNY
AND SEASONABLY MILD DAY. RELATIVELY QUIET WEATHER IS ANTICIPATED
THIS WEEK OVERALL...WITH TEMPERATURES THE MAIN FORECAST CONCERN
FOR MOST OF THE WEEK. HOWEVER...IN THE NEXT 12-24 HOURS...WE ARE
ALSO CONCERNED WITH HOW MUCH STRATUS/FOG FROM THE UPPER MIDWEST
WILL SPREAD INTO AND/OR INCREASE OVER THE FORECAST AREA.
12Z MODELS IN GOOD OVERALL AGREEMENT FOR THE NEXT FEW DAYS WITH
THE MAIN FEATURES EXPECTED TO IMPACT THE FORECAST AREA. HOWEVER...
ONLY A FEW MESOSCALE MODELS HAVE A CLUE THAT THE UPSTREAM
STRATUS/FOG EVEN EXISTS. HAVE LARGELY DISCOUNTED ANY MODEL
SOLUTION REGARDING THIS STRATUS/FOG...AND USED
EXTRAPOLATION/CONCEPTUAL MODELS TO TRY AND PIN POINT HOW THEY WILL
IMPACT THE AREA. IN THE LONGER RANGE OF THE FORECAST...
MODEL/ENSEMBLE SPREAD IS STILL PRETTY LARGE WITH HOW THE VORTEX
OVER EASTERN CANADA WILL DEVELOP DURING THE WEEK...AND HOW MUCH
COLD AIR ASSOCIATED WITH THIS VORTEX WILL DIP INTO THE MIDWEST.
SHORT TERM...TONIGHT THROUGH WEDNESDAY...A NEAR SURFACE...ROUGHLY
1000 FOOT THICK STRATUS DECK HAS BEEN OVER THE UPPER MIDWEST THE
PAST COUPLE OF DAYS. IT IS TRAPPED BENEATH A SUBSIDENCE INVERSION
AND IS LIKELY AIDED BY A LITTLE BIT OF SNOW COVER IN THE AREA.
THIS DECK HAS BEEN SINKING SOUTH TODAY WITH THE SURFACE/BOUNDARY
LAYER FLOW AND HAS NOT DIMINISHED TO ANY LARGE DEGREE...AT LEAST
TO THE SOUTH/EAST OF THE SURFACE RIDGE. THE SURFACE RIDGE WILL
SLOWLY SINK SOUTHEAST ACROSS THE FORECAST AREA TONIGHT AND IT
APPEARS LIKELY TO BRING THE STRATUS/FOG WITH IT. THE LOSS OF
DIURNAL HEATING IN A FEW HOURS IS ALSO APT TO LET THE EDGES OF
THE CLOUD DECK SPREAD OUT LARGER THAN ITS CURRENT AREAL EXTENT.
WHILE THE CLOUDS/FOG ARE LIKELY TO ONLY IMPACT WESTERN SECTIONS OF
THE FORECAST AREA THIS EVENING...IT SHOULD SPREAD EAST OVERNIGHT
AS SURFACE/BOUNDARY LAYER FLOW STARTS TURNING WESTERLY ON THE BACK
SIDE OF THE SURFACE RIDGE.
EXPECT CLOUDS/FOG TO BREAK UP MONDAY AFTERNOON ON THE BACK SIDE OF
THE RIDGE...MUCH AS IS OCCURRING ACROSS MINNESOTA AND THE EASTERN
DAKOTAS TODAY. HOWEVER...THIS CLEARING IS NOT LIKELY TO OCCUR SOON
ENOUGH TO ALLOW TEMPERATURES TO REACH MOST GUIDANCE HIGH
TEMPERATURES. WITH THIS IN MIND...HAVE CUT HIGH TEMPS A CATEGORY
MONDAY. SKIES WILL NOT BE CLEAR VERY LONG AS AN APPROACHING SYSTEM
BRINGS ADDITIONAL CLOUD COVER SPILLING IN FROM THE NORTHWEST
MONDAY NIGHT.
A NORTHERN STREAM SHORT WAVE WILL DIVE THROUGH THE AREA TUESDAY...
BRINGING A MOISTURE STARVED COLD FRONT WITH IT. THIS WAVE WILL
ALSO PICK UP AN ORPHANED UPPER LOW SPINNING OVER THE ROCKIES...
WHICH WILL TRACK EAST ALONG THE FRONT INTO WEDNESDAY. THE LACK OF
MOISTURE SHOULD KEEP RAIN/SNOW CHANCES TO A MINIMUM TUESDAY INTO
WEDNESDAY...WITH THE BEST CHANCES OCCURRING ACROSS THE SOUTHERN
HALF OF THE FORECAST AREA ALONG THE TRACK OF THE ROCKIES WAVE.
TEMPERATURES WILL ALSO BE NOTICEABLY COOLER ON WEDNESDAY BEHIND THE
FRONT.
LONG TERM...THURSDAY THROUGH SUNDAY...COLD AIR IS FORECAST TO LOAD
UP OVER EASTERN CANADA DURING THE PERIOD...AND MOST MODELS HAVE AN
ARCTIC FRONT PUSHING THROUGH THE FORECAST AREA IN THE VICINITY OF
FRIDAY. THIS FRONT WILL ALSO BE MOISTURE STARVED AND SHOULD COME
THROUGH DRY. THERE ARE A WIDE RANGE OF SOLUTIONS WITH RESPECT TO
HOW MUCH COLD AIR WILL SETTLE IN BEHIND THE FRONT. WILL MAINTAIN
TEMPERATURES AT OR BELOW NORMAL FOR THE WEEKEND...BUT THE DETAILS
ARE STILL SUBJECT TO SIGNIFICANT CHANGE.
BAK
&&
.AVIATION...
ISSUED 1153 AM CST SUN FEB 5 2012
ISSUES WITH SPREADING STRATUS FROM THE NORTH AND WEST...AND SMALL
SWATH OF FOG HEADED FOR BMI AND PIA THIS AFTERNOON. MODELS ARE
DOING VERY POORLY WITH THE LLVL RH. HRRR MODEL HAS A BIT MORE
USEFULNESS IN THE SHORT TERM...AND TAFS ARE LEANING HEAVILY ON
THAT SOLUTION. SPREADING THE IFR STRATUS INTO PIA AND BMI AND SPI
LATER THIS AFTERNOON. ISSUE WILL BE THE COLLISION OF THE STRATUS
WITH THE IFR/LIFR VIS AND CIGS FOR BMI AND PIA. BREAKING SPI AND
DEC OUT OF THE CLOUDS IN THE MORNING...BUT CONFIDENCE IS LOW FOR
ANY AND ALL SOLUTIONS. TREND ANALYSIS WOULD KEEP IFR IN PIA BMI
AND CMI THROUGH THE OVERNIGHT...BUT POTENTIAL FOR THOSE SAME
CLOUDS TO CREEP TO SRN TERMINALS IS VERY POSSIBLE.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1202 PM CST SUN FEB 5 2012
.DISCUSSION...
ISSUED 1039 AM CST SUN FEB 5 2012
FORECAST IS DOING JUST FINE OVERALL...BUT NEED TO WATCH A SMALL
SWATH OF FOG APPROACHING FROM THE NORTH...THAT IS ERODING AS IT
MOVES INTO THE CWA...SIMILAR TO THE FOG OVER CMI/DNV AREA THAT IS
FINALLY BURNING OFF. WILL UPDATE THE ZONES TO ELIMINATE MORNING
WORDING...AND PUT SOME PATCHY FOG IN FOR THE BMI TO PIA CORRIDOR
ALONG INTERSTATE 74 FOR THE NEXT COUPLE HOURS. ANOTHER ISSUE WILL
BE SOME LLVL STRATUS TO THE NORTH AND WEST THAT IS INCORRECTLY
REPRESENTED IN ALL THE MODELS. HOWEVER...DVN AND ILX SOUNDINGS
HAVE ENOUGH DRY AIR FROM 900 TO 700 MB TO ERODE SOME OF THAT AS
WELL. MAY BE A DAY OF MULTIPLE UPDATES OVERALL.
&&
.AVIATION...
ISSUED 1153 AM CST SUN FEB 5 2012
ISSUES WITH SPREADING STRATUS FROM THE NORTH AND WEST...AND SMALL
SWATH OF FOG HEADED FOR BMI AND PIA THIS AFTERNOON. MODELS ARE
DOING VERY POORLY WITH THE LLVL RH. HRRR MODEL HAS A BIT MORE
USEFULNESS IN THE SHORT TERM...AND TAFS ARE LEANING HEAVILY ON
THAT SOLUTION. SPREADING THE IFR STRATUS INTO PIA AND BMI AND SPI
LATER THIS AFTERNOON. ISSUE WILL BE THE COLLISION OF THE STRATUS
WITH THE IFR/LIFR VIS AND CIGS FOR BMI AND PIA. BREAKING SPI AND
DEC OUT OF THE CLOUDS IN THE MORNING...BUT CONFIDENCE IS LOW FOR
ANY AND ALL SOLUTIONS. TREND ANALYSIS WOULD KEEP IFR IN PIA BMI
AND CMI THROUGH THE OVERNIGHT...BUT POTENTIAL FOR THOSE SAME
CLOUDS TO CREEP TO SRN TERMINALS IS VERY POSSIBLE.
HJS
&&
.PREV DISCUSSION...
ISSUED 240 AM CST SUN FEB 5 2012
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL U.S. EARLY THIS
MORNING...WITH WATER VAPOR IMAGERY SHOWING IT CENTERED NEAR KANSAS
CITY...WITH A SECOND LOW FURTHER WEST ACROSS UTAH. CLEARING LINE
HAS BEEN QUICKLY MOVING SOUTH ACROSS THE NORTHERN CWA THE LAST FEW
HOURS...AND WAS JUST SOUTH OF THE I-74 CORRIDOR AT 2 AM. INITIAL
FORECAST CHALLENGE WILL BE WITH CLEARING TREND AND FOG POTENTIAL
EARLY ON...AS CLOUDS BREAK IN AREAS THAT HAD DECENT RAINFALL THE
LAST 24-36 HOURS. HOWEVER...THE PRIMARY FORECAST ISSUE WILL BE
WITH TREND FOR COLD WEATHER TOWARD THE END OF THE WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
LATEST HRRR NOT TOO FAR OFF WITH CURRENT POSITIONING OF THE
STRATUS...AND SHOWS MUCH OF THE CWA SHOULD BE STRATUS-FREE BY LATE
MORNING. NORTHERN CWA IS MOST VULNERABLE FOR SOME FOG EARLY...WITH
LACON CURRENTLY REPORTING 3/4 MILE AND BLOOMINGTON 1-3/4 MILE AS
THE CLOUDS HAVE BROKEN. SO FAR NOTHING NORTH OF THERE IS GETTING
OUT OF HAND YET DESPITE A LONGER CLEAR PERIOD...SO WILL MAKE A
LAST MINUTE DECISION ON WHETHER TO CONTINUE FOG POTENTIAL BEYOND
SUNRISE.
MISSOURI UPPER LOW PROGGED TO DRIFT SOUTHEAST TO THE LOWER OHIO
VALLEY BY TONIGHT. ANY RESIDUAL LIGHT RAIN/DRIZZLE WILL CONTINUE
TO SHRINK WITH THIS LOW...AND WILL LIKELY ONLY MENTION IT IN THE
FAR SOUTHEAST FOR EARLY TODAY. SURFACE HIGH PRESSURE RIDGING
EASTWARD POSES ANOTHER CONCERN FOR LOW CLOUDS/FOG TONIGHT. LATEST
SREF GRAPHICS SHOWING THE NORTHWEST CWA BEING OVERSPREAD BY LOWER
STRATOCUMULUS AFTER MIDNIGHT...LASTING UNTIL ABOUT MID-MORNING
MONDAY. GIVEN THAT THIS AREA SHOULD SEE DECENT SUNSHINE MUCH OF
TODAY TO HELP DRY THINGS OUT...AM NOT OVERLY CONFIDENT IN THIS
CLOUD SCENARIO AT THE MOMENT. FOR NOW...WILL GO WITH PARTLY CLOUDY
CONDITIONS ACROSS THE NORTHWEST TONIGHT AND MAINLY CLEAR
ELSEWHERE...WITH THE DAY SHIFT MAKING ANY FURTHER ADJUSTMENTS AS
THE DAYTIME TRENDS PLAY OUT.
LEFTOVER CUTOFF ENERGY OVER THE CENTRAL ROCKIES SHOULD WEAKEN AND
GET PICKED UP BY A TROUGH MOVING ALONG THE CANADIAN BORDER MONDAY
NIGHT AND TUESDAY. NOT A LOT OF MOISTURE AVAILABLE OVERHEAD WHEN
IT ARRIVES...BUT SOME RESIDUAL MOISTURE ACCOMPANYING THE LEFTOVER
ENERGY IS ENOUGH TO WARRANT SLIGHT CHANCE POPS FOR TUESDAY AND
TUESDAY NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY...
QUIET WEATHER EXPECTED MIDWEEK AS HIGH PRESSURE DRIFTS ACROSS THE
MIDWEST. MAIN CONCERN REMAINS WITH THE AMOUNT OF ARCTIC AIR THAT
WILL BE DROPPING SOUTHEASTWARD LATE IN THE WEEK. GFS BRINGS 850 MB
TEMPERATURES OF -16C ACROSS MOST OF THE CWA BY FRIDAY EVENING...
WHILE ECMWF GIVES US MORE OF A GLANCING BLOW WITH THE CORE OF THE
COLDER AIR CLOSER TO THE GREAT LAKES. HAVE BEGUN TO TREND DOWNWARD
WITH THE TEMPERATURE FORECASTS AS THE MAIN IDEA HAS BEEN
PERSISTENT FOR A COUPLE DAYS NOW...BUT NOT AS AGGRESSIVELY AS THE
GFS WOULD INDICATE...WHICH GIVES THE NORTHERN CWA A STRUGGLE TO
REACH 20 DEGREES ON FRIDAY. THAT MAY BE TOUGH WITHOUT ANY SNOW ON
THE GROUND...BUT WE SHOULD STILL SEE SOMEWHAT OF A COLD SNAP IN
AN OTHERWISE MILD WINTER.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1049 AM CST SUN FEB 5 2012
.DISCUSSION...
ISSUED 1039 AM CST SUN FEB 5 2012
FORECAST IS DOING JUST FINE OVERALL...BUT NEED TO WATCH A SMALL
SWATH OF FOG APPROACHING FROM THE NORTH...THAT IS ERODING AS IT
MOVES INTO THE CWA...SIMILAR TO THE FOG OVER CMI/DNV AREA THAT IS
FINALLY BURNING OFF. WILL UPDATE THE ZONES TO ELIMINATE MORNING
WORDING...AND PUT SOME PATCHY FOG IN FOR THE BMI TO PIA CORRIDOR
ALONG INTERSTATE 74 FOR THE NEXT COUPLE HOURS. ANOTHER ISSUE WILL
BE SOME LLVL STRATUS TO THE NORTH AND WEST THAT IS INCORRECTLY
REPRESENTED IN ALL THE MODELS. HOWEVER...DVN AND ILX SOUNDINGS
HAVE ENOUGH DRY AIR FROM 900 TO 700 MB TO ERODE SOME OF THAT AS
WELL. MAY BE A DAY OF MULTIPLE UPDATES OVERALL.
HJS
&&
.AVIATION...
ISSUED 515 AM CST SUN FEB 5 2012
SEVERAL FORECAST CONCERNS THIS PERIOD WITH THE MAIN SHORT TERM
CONCERN BEING WITH THE FOG POTENTIAL THRU 15Z AND MOVEMENT OF IFR
CIGS JUST SOUTH OF OUR TAF SITES. SECOND CONCERN WILL BE TRACK OF
MVFR/IFR CIGS ACRS NRN IOWA AND OVER PARTS OF NE IL EARLY THIS
MORNING.
BACK-EDGE OF LOWER CLOUDS HAS SHIFTED JUST SOUTH OF SPI AND DEC
AS OF 10Z. EXPECT THE SLOW SOUTH MOVEMENT OF THESE CLOUDS TO
CONTINUE WITH SOME RAGGED MID LEVEL CLOUDS ACRS THE REMAINDER
OF THE FCST AREA. WITH THE RESIDUAL LOW LEVEL MOISTURE IN PLACE
FROM THE RAIN YESTERDAY AND CLEARING SKIES...PATCHY FOG WAS
PREVALENT OVER THE AREA. WILL CONTINUE WITH A TEMPO GROUP FOR
FOG THRU 15Z AND THEN VFR CONDITIONS ARE EXPECTED THRU LATE THIS
AFTERNOON. WITH THE LOW LEVEL MOISTURE IN PLACE AND SUNSHINE
EXPECTED TODAY...WE SHOULD SEE AT LEAST A SCATTERED CU FIELD
DEVELOP DESPITE THE SIGNIFICANT DRYING TAKING PLACE ABOVE 850 MB.
OUR ATTENTION THEN WILL TURN TO THE LOWER CLOUDS TO OUR NORTH AND
NORTHWEST. SHORT RANGE MODELS SUGGEST THE POTENTIAL FOR SOME OF
THE LOWER CIGS TO EDGE INTO WESTERN IL BY MID OR LATE THIS AFTN
AND EARLY THIS EVENING. CONFIDENCE RATHER LOW REGARDING MOVEMENT
OF THE CLOUD DECK LATER THIS AFTN AS LOW LEVEL WIND PROFILES
INDICATE WINDS WILL BACK FROM THE CURRENT NORTHERLY DIRECTION MORE
INTO THE WEST LATE TODAY...WHICH MAY AID IN MORE OF AN EASTWARD
TRAJECTORY TO THE IFR/MVFR CIGS CURRENTLY OVER IOWA. THAT WILL
HAVE TO BE WATCHED IN LATER FORECASTS...BUT FOR NOW WILL HOLD ON
TO THE VFR CONDITIONS THRU LATE THIS AFTN AND THEN INTRODUCE A
SCATTERED CLOUD GROUP AT AROUND 1500 FEET AT PIA LATER TODAY.
SURFACE WINDS WILL CONTINUE FROM A NORTHERLY DIRECTION TODAY AT
AROUND 10 KTS...AND THEN BACK INTO THE NORTHWEST AND THEN WEST
LATE THIS AFTN AND EVENING...WITH SPEEDS AFTR 00Z DROPPING OFF
TO AROUND 5 KTS OR LESS.
SMITH
&&
.PREV DISCUSSION...
ISSUED 240 AM CST SUN FEB 5 2012
UPPER LOW CONTINUES TO SPIN ACROSS THE CENTRAL U.S. EARLY THIS
MORNING...WITH WATER VAPOR IMAGERY SHOWING IT CENTERED NEAR KANSAS
CITY...WITH A SECOND LOW FURTHER WEST ACROSS UTAH. CLEARING LINE
HAS BEEN QUICKLY MOVING SOUTH ACROSS THE NORTHERN CWA THE LAST FEW
HOURS...AND WAS JUST SOUTH OF THE I-74 CORRIDOR AT 2 AM. INITIAL
FORECAST CHALLENGE WILL BE WITH CLEARING TREND AND FOG POTENTIAL
EARLY ON...AS CLOUDS BREAK IN AREAS THAT HAD DECENT RAINFALL THE
LAST 24-36 HOURS. HOWEVER...THE PRIMARY FORECAST ISSUE WILL BE
WITH TREND FOR COLD WEATHER TOWARD THE END OF THE WEEK.
SHORT TERM...TODAY THROUGH TUESDAY...
LATEST HRRR NOT TOO FAR OFF WITH CURRENT POSITIONING OF THE
STRATUS...AND SHOWS MUCH OF THE CWA SHOULD BE STRATUS-FREE BY LATE
MORNING. NORTHERN CWA IS MOST VULNERABLE FOR SOME FOG EARLY...WITH
LACON CURRENTLY REPORTING 3/4 MILE AND BLOOMINGTON 1-3/4 MILE AS
THE CLOUDS HAVE BROKEN. SO FAR NOTHING NORTH OF THERE IS GETTING
OUT OF HAND YET DESPITE A LONGER CLEAR PERIOD...SO WILL MAKE A
LAST MINUTE DECISION ON WHETHER TO CONTINUE FOG POTENTIAL BEYOND
SUNRISE.
MISSOURI UPPER LOW PROGGED TO DRIFT SOUTHEAST TO THE LOWER OHIO
VALLEY BY TONIGHT. ANY RESIDUAL LIGHT RAIN/DRIZZLE WILL CONTINUE
TO SHRINK WITH THIS LOW...AND WILL LIKELY ONLY MENTION IT IN THE
FAR SOUTHEAST FOR EARLY TODAY. SURFACE HIGH PRESSURE RIDGING
EASTWARD POSES ANOTHER CONCERN FOR LOW CLOUDS/FOG TONIGHT. LATEST
SREF GRAPHICS SHOWING THE NORTHWEST CWA BEING OVERSPREAD BY LOWER
STRATOCUMULUS AFTER MIDNIGHT...LASTING UNTIL ABOUT MID-MORNING
MONDAY. GIVEN THAT THIS AREA SHOULD SEE DECENT SUNSHINE MUCH OF
TODAY TO HELP DRY THINGS OUT...AM NOT OVERLY CONFIDENT IN THIS
CLOUD SCENARIO AT THE MOMENT. FOR NOW...WILL GO WITH PARTLY CLOUDY
CONDITIONS ACROSS THE NORTHWEST TONIGHT AND MAINLY CLEAR
ELSEWHERE...WITH THE DAY SHIFT MAKING ANY FURTHER ADJUSTMENTS AS
THE DAYTIME TRENDS PLAY OUT.
LEFTOVER CUTOFF ENERGY OVER THE CENTRAL ROCKIES SHOULD WEAKEN AND
GET PICKED UP BY A TROUGH MOVING ALONG THE CANADIAN BORDER MONDAY
NIGHT AND TUESDAY. NOT A LOT OF MOISTURE AVAILABLE OVERHEAD WHEN
IT ARRIVES...BUT SOME RESIDUAL MOISTURE ACCOMPANYING THE LEFTOVER
ENERGY IS ENOUGH TO WARRANT SLIGHT CHANCE POPS FOR TUESDAY AND
TUESDAY NIGHT.
LONG TERM...WEDNESDAY THROUGH SATURDAY...
QUIET WEATHER EXPECTED MIDWEEK AS HIGH PRESSURE DRIFTS ACROSS THE
MIDWEST. MAIN CONCERN REMAINS WITH THE AMOUNT OF ARCTIC AIR THAT
WILL BE DROPPING SOUTHEASTWARD LATE IN THE WEEK. GFS BRINGS 850 MB
TEMPERATURES OF -16C ACROSS MOST OF THE CWA BY FRIDAY EVENING...
WHILE ECMWF GIVES US MORE OF A GLANCING BLOW WITH THE CORE OF THE
COLDER AIR CLOSER TO THE GREAT LAKES. HAVE BEGUN TO TREND DOWNWARD
WITH THE TEMPERATURE FORECASTS AS THE MAIN IDEA HAS BEEN
PERSISTENT FOR A COUPLE DAYS NOW...BUT NOT AS AGGRESSIVELY AS THE
GFS WOULD INDICATE...WHICH GIVES THE NORTHERN CWA A STRUGGLE TO
REACH 20 DEGREES ON FRIDAY. THAT MAY BE TOUGH WITHOUT ANY SNOW ON
THE GROUND...BUT WE SHOULD STILL SEE SOMEWHAT OF A COLD SNAP IN
AN OTHERWISE MILD WINTER.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
340 PM EST SUN FEB 5 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...A SUNNY...SUPER AFTERNOON ACROSS CENTRAL INDIANA WILL
LEAD TO A CLEAR NIGHT WITH SOME POTENTIAL FOR FOG LATE. A SERIES OF
WEAK UPPER WAVES WILL MOVE THROUGH THE FLOW THIS WEEK BUT HIGH
PRESSURE WILL BE THE RULE AT THE SURFACE SO PRECIPITATION CHANCES
FOR MOST OF THE WEEK ARE SMALL.
&&
.NEAR TERM /REST OF TODAY AND TONIGHT/...
VISIBLE SATELLITE LOOP AT 20Z SHOWS SUNNY SKIES ACROSS THE
AREA...AND LATEST OBSERVATIONS SHOW TEMPERATURES RANGING FROM THE
MIDDLE 40S TO AROUND 50...MAKING IT A SUPER WEATHER DAY FOR FEBRUARY
IN CENTRAL INDIANA. CLEAR SKIES WILL CONTINUE INTO TONIGHT WITH HIGH
PRESSURE BUILDING IN AND WINDS WILL GO CALM OR NEAR CALM. THIS WILL
LEAD TO THE POTENTIAL FOR SOME FOG OVERNIGHT. WITH THE SUNSHINE THE
AREA RECEIVED TODAY SOILS SHOULD HAVE HAD PLENTY OF TIME TO DRY OUT
SOME AND DEW POINTS ARE RUNNING DRIER THAN GUIDANCE SO AS OF NOW DO
NOT ANTICIPATE WIDESPREAD DENSE FOG...JUST SOME PATCHY FOG ACROSS
THE AREA DEVELOPING LATE AND LASTING UNTIL A COUPLE OF HOURS AFTER
SUNRISE.
&&
.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
HIGH PRESSURE WILL CONTINUE TO BE IN PLACE AT THE SURFACE WITH THE
CUTOFF UPPER LOW MAKING ITS WAY EAST JUST SOUTH OF THE AREA ON
MONDAY. THIS COULD LEAD TO INCREASED CLOUD COVER IN THE SOUTH BUT
THAT/S IT AS FORCING IS FAIRLY WEAK AND MOISTURE IS LIMITED. UPPER
RIDGING WILL BE IN PLACE FOR MONDAY NIGHT AND TUESDAY WHICH WILL
KEEP THE AREA DRY. BY TUESDAY NIGHT THOUGH AN UPPER WAVE WILL
APPROACH AND BRING SOME FORCING TO THE AREA THAT COULD LAST THROUGH
WEDNESDAY BUT SHOULD BE THROUGH BY WEDNESDAY NIGHT. THERE IS STILL SOME
MODEL DISCREPANCY ON TIMING...BUT THE NAM SEEMS TO BE A SLOW OUTLIER
WITH THE SREFS/GFS/ECMWF ALL POINTING TO SOMETIME IN THE TUESDAY
NIGHT TO WEDNESDAY TIME FRAME AND ONLY THE NAM HOLDING ON TO PRECIP
INTO WEDNESDAY NIGHT. ONLY WENT WITH A SLIGHT CHANCE FOR
PRECIPITATION ON TUESDAY NIGHT AND WEDNESDAY SINCE THERE IS HIGH
PRESSURE AT THE SURFACE AND MOISTURE WILL BE LIMITED...BUT UPPER
FORCING IS SUFFICIENT TO JUSTIFY A SLIGHT CHANCE. SOUNDINGS FOR THAT
TIME SUGGEST SNOW AS THE POTENTIAL PRECIPITATION TYPE SHOULD IT
OCCUR.
FOR TEMPERATURES GENERALLY USED A GUIDANCE CONSENSUS WITH GOOD
AGREEMENT THERE. THE EXCEPTION IS ON WEDNESDAY WHEN COLD ADVECTION
IS IN PLACE AN 850 MB TEMPERATURES FROM THE ECMWF AND GFS BOTH SHOW
-10C OVER THE AREA. THOUGHT GUIDANCE WAS TOO HIGH GIVEN THE ABOVE
AND INSTEAD WENT WITH AN AVERAGE OF THE GFS AND ECM.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THERE ARE A COUPLE OF PERIODS WHERE SLIGHT CHANCE OF PRECIP IS
POSSIBLE MAINLY WEDNESDAY EVENING AND AGAIN FRIDAY. HOWEVER MODELS
HAVE TRENDED DRIER WITH EACH RUN AND ALL BLEND ONLY GIVES A 15-20
PERCENT CHANCE AT MOST OF PRECIP THOSE PERIODS. AT THIS POINT HAVE
DECIDED TO TAKE OUT MENTION OF PRECIP AS NOW DRY THROUGH THE PERIODS
AND THERE ARE ONLY A FEW WEAK SYSTEMS TO KEY ON.
MODELS MOVE AN UPPER SHORT WAVE ACROSS THE OHIO VALLEY EARLY
WEDNESDAY EVENING. THEN HIGH PRESSURE WILL DOMINATE OUR WEATHER
THURSDAY. ON FRIDAY A DRY COLD FRONT WILL MOVE ACROSS OUR REGION AS
A BROAD UPPER TROUGH ROTATES ACROSS THE GREAT LAKES AND MIDWEST.
ONCE AGAIN THERE IS LIMITED MOISTURE AVAILABLE WITH THIS SYSTEM.
HIGH PRESSURE BEHIND THIS SYSTEM WILL MOVE ACROSS OUR REGION OVER
THE WEEKEND. OVERALL DID NOT MAKE ANY SIGNIFICANT CHANGES TO ALL
BLEND PARAMETERS.
&&
.AVIATION /DISCUSSION FOR 052100Z TAF UPDATE/...
ONLY VERY MINOR CHANGES BASED ON LATEST OBSERVATIONS. PREVIOUS
DISCUSSION FOLLOWS.
SATELLITE AT 1630Z SHOWS SOME LINGERING STRATUS WEST OF KLAF AND
ALONG AND SOUTH OF A KLWV-KBMG-KBAK LINE. THIS STRATUS WILL CONTINUE
TO CLEAR AND NO SIGNIFICANT CLOUD COVER IS EXPECTED THROUGH THE
PERIOD WITH MOSTLY VFR AND CLEAR SKIES THROUGH THE PERIOD.
THE ONLY ISSUE WILL BE POSSIBILITY OF SOME FOG LATE TONIGHT AND
EARLY MONDAY AS WINDS WILL BE LIGHT AND STRONG RADIATIONAL COOLING
OCCURS DURING THE OVERNIGHT HOURS. THE NAM MODEL SOUNDING INDICATES
NEAR SATURATION NEAR THE SURFACE AND THE RUC SHOWS EVEN A LITTLE
MORE BEGINNING AFTER 09Z. THERE WERE SOME AREAS OF FOG UPSTREAM
THIS MORNING SO WILL ADD MENTION OF SOME MVFR FOG ALL SITES TOWARDS
SUNRISE. ON THE NEGATIVE SIDE...THE GROUND WILL HAVE SOME TIME TO
DRY OUT THIS AFTERNOON AS THERE WILL BE FULL SUNSHINE ACROSS THE
AREA.
WINDS TODAY WILL BE FROM THE NORTHEAST 5 TO 8 KNOTS THIS
AFTERNOON...THEN LIGHT TONIGHT AND BECOMING SOUTHWEST 7 TO 10 KNOTS
AFTER 15Z MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....JH
AVIATION...JK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
330 PM EST SUN FEB 5 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
TEMPERATURES HAVE RISEN ABOVE FREEZING AND FOG HAS DISSIPATED
ACROSS THE AREA...SO ALLOWED FREEZING FOG ADVISORY IN THE NORTH TO
EXPIRE AT 10 AM. CLEARING OF LOWER CLOUD DECK WILL CONTINUE TO
OCCUR FROM NORTH TO SOUTH AS HIGH PRESSURE BUILDS IN FROM THE
NORTHWEST...MAKING FOR A MOSTLY SUNNY DAY ACROSS THE AREA. HIGH
TEMPERATURES IN THE MIDDLE TO UPPER 40S STILL LOOK GOOD AT THIS
TIME WITH LIGHT NORTHEASTERLY TO NORTHERLY WINDS. COMPARED WITH
THE LIGHT RAIN AND COOL CONDITIONS YESTERDAY A SUPER DAY IS IN
STORE TODAY FOR CENTRAL INDIANA.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.
MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.
MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.
TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.
THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.
&&
.AVIATION /DISCUSSION FOR 052100Z TAF UPDATE/...
ONLY VERY MINOR CHANGES BASED ON LATEST OBSERVATIONS. PREVIOUS
DISCUSSION FOLLOWS.
SATELLITE AT 1630Z SHOWS SOME LINGERING STRATUS WEST OF KLAF AND
ALONG AND SOUTH OF A KLWV-KBMG-KBAK LINE. THIS STRATUS WILL CONTINUE
TO CLEAR AND NO SIGNIFICANT CLOUD COVER IS EXPECTED THROUGH THE
PERIOD WITH MOSTLY VFR AND CLEAR SKIES THROUGH THE PERIOD.
THE ONLY ISSUE WILL BE POSSIBILITY OF SOME FOG LATE TONIGHT AND
EARLY MONDAY AS WINDS WILL BE LIGHT AND STRONG RADIATIONAL COOLING
OCCURS DURING THE OVERNIGHT HOURS. THE NAM MODEL SOUNDING INDICATES
NEAR SATURATION NEAR THE SURFACE AND THE RUC SHOWS EVEN A LITTLE
MORE BEGINNING AFTER 09Z. THERE WERE SOME AREAS OF FOG UPSTREAM
THIS MORNING SO WILL ADD MENTION OF SOME MVFR FOG ALL SITES TOWARDS
SUNRISE. ON THE NEGATIVE SIDE...THE GROUND WILL HAVE SOME TIME TO
DRY OUT THIS AFTERNOON AS THERE WILL BE FULL SUNSHINE ACROSS THE
AREA.
WINDS TODAY WILL BE FROM THE NORTHEAST 5 TO 8 KNOTS THIS
AFTERNOON...THEN LIGHT TONIGHT AND BECOMING SOUTHWEST 7 TO 10 KNOTS
AFTER 15Z MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...CP
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...JK
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1205 PM EST SUN FEB 5 2012
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
CLOUDS WILL DEPART EARLY THIS MORNING WITH FOG BURNING OFF THROUGH
THE MORNING AS HIGH PRESSURE BUILDS INTO CENTRAL INDIANA. THE HIGH
WILL BRING DRY WEATHER AND MAINLY CLEAR SKIES THROUGH TUESDAY. A
WEAK UPPER LEVEL DISTURBANCE WILL PROVIDE A CHANCE FOR LIGHT RAIN
AND SNOW TUESDAY NIGHT AND WEDNESDAY. THE EXPANSION OF A BROAD UPPER
LEVEL TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES FOR LATE
WEEK AND INTO NEXT WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
TEMPERATURES HAVE RISEN ABOVE FREEZING AND FOG HAS DISSIPATED
ACROSS THE AREA...SO ALLOWED FREEZING FOG ADVISORY IN THE NORTH TO
EXPIRE AT 10 AM. CLEARING OF LOWER CLOUD DECK WILL CONTINUE TO
OCCUR FROM NORTH TO SOUTH AS HIGH PRESSURE BUILDS IN FROM THE
NORTHWEST...MAKING FOR A MOSTLY SUNNY DAY ACROSS THE AREA. HIGH
TEMPERATURES IN THE MIDDLE TO UPPER 40S STILL LOOK GOOD AT THIS
TIME WITH LIGHT NORTHEASTERLY TO NORTHERLY WINDS. COMPARED WITH
THE LIGHT RAIN AND COOL CONDITIONS YESTERDAY A SUPER DAY IS IN
STORE TODAY FOR CENTRAL INDIANA.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AS AN
UPPER LEVEL DISTURBANCE MOVES INTO THE REGION.
MUCH OF THE SHORT TERM WILL REMAIN TRANQUIL AS BROAD HIGH PRESSURE
RIDGE DOMINATES THE WEATHER PATTERN OVER THE OHIO VALLEY. MODEL
SOUNDINGS MAINTAIN DEEP SUBSIDENCE OVER CENTRAL INDIANA THROUGH
MONDAY NIGHT WHICH SHOULD KEEP SKIES LARGELY CLOUD-FREE. REMNANT
UPPER LEVEL FEATURE FROM SYSTEM THIS WEEKEND WILL PASS TO THE SOUTH
OF THE REGION WITH LITTLE FANFARE AS A RESULT. WEAK FRONTAL BOUNDARY
DROPS THROUGH THE FORECAST AREA LATE MONDAY NIGHT INTO TUESDAY BUT
WILL ONLY BRING A SUBTLE INCREASE IN HIGHER CLOUDS AS NO APPRECIABLE
MOISTURE IS PRESENT.
MODELS CONVERGING ON THE ARRIVAL OF ISENTROPIC LIFT AND MOISTURE
AHEAD OF A MID LEVEL SHORT WAVE TUESDAY NIGHT. WHILE TIMING OF THE
SHORT WAVE VARIES BETWEEN THE MODELS...INTRODUCTION OF LOW CHANCE
POPS FOR TUESDAY NIGHT APPEARS WARRANTED. ANALYSIS OF LOW LEVEL
THERMALS SUPPORT POTENTIAL OF A RA/SN MIX CHANGING PREDOMINANTLY
OVER TO LIGHT SNOW AS THE NIGHT PROGRESSES. AT THIS POINT...PRECIP
AMOUNTS LOOK LIMITED AT ONLY A COUPLE HUNDREDTHS WITH SNOW ACCUMS OF
A FEW TENTHS OF AN INCH AT BEST OVER NORTHERN COUNTIES.
TEMPS...LOW LEVEL THERMAL PROFILES SUPPORTED MOS GUIDANCE THROUGH
MUCH OF THE PERIOD. TEMPS ON MONDAY SHOULD BE A FEW DEGREES WARMER
THAN TODAY WITH ABUNDANT SUNSHINE AND SOUTHWEST FLOW DEVELOPING.
PASSAGE OF THE WEAK FRONT EARLY TUESDAY WILL SERVE TO KNOCK HIGHS
DOWN A FEW DEGREES TUESDAY...WITH COLDER AIR ARRIVING TUESDAY NIGHT.
&&
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
THE MAIN FORECAST CHALLENGES FOR THE PERIOD ARE PRECIPITATION
CHANCES AND TEMPERATURES LATE IN THE PERIOD AS A DECENT PUSH OF
COLDER AIR SLIDES DOWN FROM CANADA.
THE MODELS ARE BEGINNING TO COME INTO AGREEMENT WITH THE TIMING OF
AN UPPER LEVEL WAVE PASSING THROUGH THE FORECAST AREA ON WEDNESDAY
WITH THE ECMWF JUST SLIGHTLY FASTER THAN THE GFS AND CANADIAN.
SUFFICIENT MOISTURE STILL LOOKS TO BE THE LIMITING FACTOR SO
STICKING WITH CHANCE POPS PROVIDED BY ALLBLEND SEEMS LIKE THE BEST
MOVE FOR NOW. ALSO INTRODUCED A SLIGHT CHANCE ACROSS THE EAST FOR
WEDNESDAY NIGHT TO ACCOUNT FOR THE SLIGHTLY SLOWER MODEL SOLUTIONS.
WITH TEMPERATURES CONTINUING TO BE AROUND NORMAL VALUES...LOWS IN
THE MID 20S AND HIGHS IN THE MID 30S...CONTINUED WITH A RAIN/SNOW
MIX IN THE GRIDS.
SURFACE HIGH PRESSURE WILL SLIDE ACROSS THE REGION ON THURSDAY. THIS
WILL CAUSE SOUTHWESTERLY WINDS TO RETURN ALLOWING TEMPERATURES TO
RISE TO ABOVE NORMAL VALUES ONCE AGAIN. HOWEVER...THE WARM UP WILL
BE SHORT LIVED AS A STRONG UPPER LOW NEAR HUDSON BAY TRANSPORTS A
MUCH COLDER AIRMASS TOWARDS CENTRAL INDIANA. DECREASED ALLBLEND
TEMPERATURES 2-3 DEGREES HEADING INTO THE WEEKEND WITH THE GFS
DEPICTING 850 MB TEMPERATURES APPROACHING -20 C.
&&
.AVIATION /DISCUSSION FOR THE 06/18Z TAF ISSUANCE/...
SATELLITE AT 1630Z SHOWS SOME LINGERING STRATUS WEST OF KLAF AND
ALONG AND SOUTH OF A KLWV-KBMG-KBAK LINE. THIS STRATUS WILL CONTINUE
TO CLEAR AND NO SIGNIFICANT CLOUD COVER IS EXPECTED THROUGH THE
PERIOD WITH MOSTLY VFR AND CLEAR SKIES THROUGH THE PERIOD.
THE ONLY ISSUE WILL BE POSSIBILITY OF SOME FOG LATE TONIGHT AND
EARLY MONDAY AS WINDS WILL BE LIGHT AND STRONG RADIATIONAL COOLING
OCCURS DURING THE OVERNIGHT HOURS. THE NAM MODEL SOUNDING INDICATES
NEAR SATURATION NEAR THE SURFACE AND THE RUC SHOWS EVEN A LITTLE
MORE BEGINNING AFTER 09Z. THERE WERE SOME AREAS OF FOG UPSTREAM
THIS MORNING SO WILL ADD MENTION OF SOME MVFR FOG ALL SITES TOWARDS
SUNRISE. ON THE NEGATIVE SIDE...THE GROUND WILL HAVE SOME TIME TO
DRY OUT THIS AFTERNOON AS THERE WILL BE FULL SUNSHINE ACROSS THE
AREA.
WINDS TODAY WILL BE FROM THE NORTHEAST 5 TO 8 KNOTS THIS
AFTERNOON...THEN LIGHT TONIGHT AND BECOMING SOUTHWEST 7 TO 10 KNOTS
AFTER 15Z MONDAY.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...CP
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...JH
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
309 PM CST SUN FEB 5 2012
.SYNOPSIS...
STRATUS HAS BEEN THE MAIN FOCUS OF THE DAY...WITH STRATUS EXTENDING
FROM SOUTHEAST MINNESOTA AND WESTERN WISCONSIN...NEARLY ALL OF
IOWA...AND EXTENDING BACK INTO EASTERN NEBRASKA. IT HAS MAINLY
AFFECTED THE WESTERN HALF OF THE FORECAST AREA...WITH AREAS ALONG
AND EAST OF THE MISSISSIPPI RIVER MOSTLY IN THE CLEAR. THIS STRATUS
IS TRAPPED UNDER A STRONG SURFACE HIGH PRESSURE WHICH IS CENTERED
OVER KANSAS....WITH A BROAD RIDGE EXTENDING NORTHEAST UP OVER IOWA
AND EXTENDING UP INTO WISCONSIN. SOUNDINGS FROM THIS MORNING...
AIRCRAFT REPORTS AND AIRCRAFT SOUNDINGS FROM THE AREA TODAY INDICATE
THAT WE HAVE A SATURATED LAYER AROUND 950MB...GENERALLY ABOUT 1000
TO 1500 FEET THICK DEPENDING ON THE LOCATION...WITH A STEEP
INVERSION JUST ABOVE IT. AT UPPER LEVELS THE UPPER LEVEL LOW THAT
PRODUCED RAIN AND SNOW YESTERDAY OVER IOWA IS NOW SHIFTING RAPIDLY
SOUTH ACROSS MISSOURI. CLOUDS...BUT LITTLE RAIN IS CONTINUING TO
AFFECT SOUTHERN MISSOURI AND INTO KENTUCKY AND TENNESSEE. ..LE..
&&
.SHORT TERM...TONIGHT AND MONDAY...
STRATUS REMAINS THE MAIN FORECAST CHALLENGE. THE LARGE SCALE MODELS
WE ARE USED TO DEPENDING UPON HAVE NOT EVEN INITIALIZED THE LOW
LEVEL MOISTURE ASSOCIATED WITH THE STRATUS CORRECTLY. THUS...THESE
MODELS ARE OF LITTLE USE IN PREDICTING IT. OF THE MESOSCALE
MODELS...ONLY THE HRRR SEEMS TO HAVE ANY SORT OF HANDLE ON THE
STATUS OF THE STRATUS. THUS...BETWEEN IT...EXPERIENCE AND
NOWCASTING TECHNIQES ARE ABOUT THE ONLY DECENT FORECAST TOOLS
TODAY. SINCE THE MOISTURE IS TRAPPED BENEATH THE SURFACE RIDGE
AXIS...ANTICIPATE THE STRATUS SHOULD REFORM AND SPREAD BACK
SOUTHEAST AGAIN THIS EVENING...ADVECTING ALONG IN THE NORTHWEST
925MB FLOW. OVER THE DAKOTAS TODAY THINGS SEEM TO HAVE CLEARED
NICELY WHERE THESE WINDS TURNED WESTERLY AND THE DOWNSLOPE COMPONENT
COULD HELP ACT TO DRY AND WARM THIS LAYER...HELPING TO DISSIPATE THE
CLOUDS. HOWEVER...DOWNSLOPE WILL NOT HELP US THIS FAR EAST AND THOUGH I
EXPECT THE 925MB WINDS TO TURN WESTERLY FOR US AFTER MIDNIGHT
TONIGHT THE STRATUS SHOULD LINGER THROUGH THE OVERNIGHT HOURS. UNDER
THE STRATUS LAST NIGHT MIN TEMPS ONLY DROPPED INTO THE MID TO UPPER
20S...SO HAVE CONTINUED THIS.
MONDAY MORNING AND AFTERNOON LOOKS LIKE OUR BEST OPPORTUNITY FOR
CLEARING OUT THIS BAND OF STRATUS. THE WESTERLY 925MB FLOW
STRENGTHENS TO 925MB...SOME WARM AIR ADVECTION AT THAT LAYER SHOULD
HELP TO DISSIPATE IT...ALONG WITH SHEER BODILY ADVECTION. IT IS
NOTORIOUSLY HARD TO GET RID OF STRATUS THIS TIME OF YEAR...BUT THAT
IS USUALLY DUE TO ESTABLISHED SNOWCOVER. HOPEFULLY WITH THE SNOW
GONE FOR OUR AREA WE CAN GET RID OF THE STRATUS SOONER.
ANTICIPATING MORE CLOUD COVER OVER THE EAST HAVE KEPT MAX TEMPS
THERE COOLER...BUT NOT AS COOL AS THE NORTHWEST IS TODAY.
OTHERWISE...40-45 IS NOT UNREASONABLE AS LONG AS WE CLEAR BY EARLY
AFTERNOON. ..LE..
.LONG TERM...MONDAY NIGHT THROUGH NEXT SUNDAY...
FORECAST FOCUS ON POTENTIAL FOR FLURRIES MONDAY NIGHT AND TUESDAY
OTHERWISE MAINLY A DRY PERIOD. BRIEF SHOT OF ARCTIC AIR AT THE END
OF THE NEW WORK WEEK.
MONDAY NIGHT AND TUESDAY...COLD FRONT TO ARRIVE MONDAY NIGHT WITH
POTENTIAL FOR SOME FLURRIES OR BRIEF LIGHT SNOW. EXTENSIVE LOW
STRATUS TO DEVELOP BEHIND THE FRONT AS WE COLD ADVECT MONDAY NIGHT
WITH LOW CLOUDS CONTINUING ON TUESDAY AS SURFACE WINDS TURN
NORTHEAST. WILL CONTINUE WITH SLIGHT CHANCE POPS IN OUR SOUTH BUT
EVEN THE ECM HAS BACKED OFF ON QPF AMOUNTS. TEMPERATURES ON TUESDAY
ONLY COOL DOWN TO NEAR NORMAL FOR EARLY FEBRUARY. MAXIMUM
TEMPERATURES EXPECTED TO BE IN THE 30S.
TUESDAY NIGHT THROUGH THURSDAY...EXTENSIVE LOW STRATUS TO REMAIN
TUESDAY NIGHT AND FOR MOST OF WEDNESDAY WITH FORECAST SOUNDINGS
INDICATING NORTHEAST LOW LEVEL WINDS. WILL TRY TO CLEAR THE SKIES
OUT BY WEDNESDAY NIGHT AS WINDS TURN WEST TO SOUTHWEST. MAX TEMPS
ABOUT NORMAL WITH HIGHS IN THE 30S TO NEAR 40.
THURSDAY NIGHT THROUGH SATURDAY NIGHT...TROUGH STRONGLY DIGS INTO
THE MIDWEST/GREAT LAKES TIED TO A DEEP LOW NEAR HUDSON BAY. THIS
SENDS AN ARCTIC FRONT SWEEPING RAPIDLY THROUGH THE DVN CWA THURSDAY
NIGHT. HOWEVER DUE TO THE LACK OF SIGNIFICANT SNOW COVER TO OUR
NORTH AND NO SNOW COVER IN THE DVN CWA THIS AIRMASS WILL BE MODIFIED
BY THE TIME IT GETS HERE. THE COLDEST DAY WILL BE FRIDAY BUT
SATURDAY WONT EXACTLY BE A PICNIC EITHER. HIGHS WILL BE IN THE MID
20S NORTH TO LOWER 30S SOUTH WITH LOWS MAINLY IN THE TEENS. WARM
ADVECTION ALREADY UNDERWAY BY SATURDAY NIGHT AS ARCTIC HIGH PRESSURE
SHIFTS INTO THE OHIO VALLEY RETURNING SOUTH WINDS TO THE REGION.
SUNDAY...NICE WARM-UP BEGINS AS UPPER LEVEL FLOW BECOMES ZONAL TO
SOUTHWEST WITH SOUTHWEST SURFACE WINDS. MAX TEMPS SHOULD PUSH WELL
INTO THE 30S NORTH TO LOWER 40S SOUTH. EVEN WARMER TEMPERATURES
EARLY NEXT WEEK.
..HAASE..
&&
.AVIATION... /ISSUED 1214 PM CST SUN FEB 5 2012/
LARGE AREA STRATUS AND FOG WITH IFR TO LIFR CONDITIONS WAS
CONTINUING TO AFFECT MUCH OF IOWA. THIS STRATUS IS TRAPPED
UNDERNEATH A STRONG HIGH PRESSURE RIDGE OVER THE CENTRAL PLAINS.
IT WILL GRADUALLY SHIFT SOUTHEAST TODAY AND TONIGHT. THE EASTWARD
PROGRESS OF THE STRATUS HAS STALLED OR SLOWED DOWN...AND EXPECT A
CERTAIN AMOUNT OF RETREAT THIS AFTERNOON AS THE SUNSHINE WORKS TO
DISSIPATE IT. IT ALSO HELPS THAT THE STRATUS IS THIN...LATEST
PIREPS INDICATE THAT CLOUD TOPS ARE AROUND 1500 FT AGL. KDBQ...
KMLI AND KBRL SHOULD REMAIN NEAR THE EDGE OF THE STRATUS AND HAVE
INCLUDED TEMPOS GROUPS FOR THIS AFTERNOON. KCID IS LIKELY TO
REMAIN IFR IN THE STRATUS...BUT HAVE GONE OPTIMISTIC WITH A SHORT
TEMPO GROUP FOR VFR AS WELL. NEAR SUNSET EXPECT THE STRATUS TO
EXPAND AGAIN...AND CONDITIONS WILL DETERIORATE BACK TO IFR OR EVEN
LIFR FOR MOST OF THE NIGHT. THE SURFACE RIDGE FINALLY SHIFTS EAST OF
THE AREA MONDAY MORNING...AND EXPECT THE STRATUS TO FINALLY MOVE
OUT BY 14-16Z AND LEAVE US WITH VFR CONDITIONS. WINDS THROUGH
PERIOD TO REMAIN LIGHT...BUT WILL BE LIGHT NORTH THIS AFTERNOON
AND GRADUALLY SWITCH TO WEST LATE TONIGHT AND EARLY MONDAY
MORNING. ..LE..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
LE/HAASE
AREA FORECAST DISCUSSION
NWS DES MOINES IA
1155 AM CST SUN FEB 5 2012
.SHORT TERM /TODAY/...
WIDESPREAD STRATUS FIELD CURRENTLY PUSHING SOUTH THOUGH NORTHERN IA
EARLY THIS MORNING AND REPRESENTS THE FORECAST CHALLENGE OF THE DAY.
THE STRATUS HAS BE SHIFTING SOUTH AT 16 KTS THE PAST FEW HOURS. THIS
WOULD BRING IT TO THE MISSOURI BORDER AROUND 16Z. THE HRRR HAS
INITIALIZED THE CLOUD PROGRESSION WELL AND SUGGESTS THEY WILL STICK
AROUND MOST OF THE DAY. IF ANY EROSION DOES OCCUR...IT WILL BE ON
THE OUTSIDE EDGES AND THIS WOULD LEAVE CENTRAL IA THE LAST TO
DISSIPATE. WITH NEW SNOW PACK OVER THE SOUTH...LIGHT WINDS AND LACK
OF STRONG SUBSIDENCE...FAVOR THE CLOUDY SOLUTION. THE LACK OF SUN
WILL RESULT IN BELOW GUIDANCE HIGHS TODAY. EXPECT SOME FOG EARLY IN
THE PERIOD AND THE POSSIBILITY REMAINS OF LOCALLY DENSE FOG. BEST
POTENTIAL WILL BE SOUTH OF HIGHWAY 30 AS THE HIGHER DEWPOINTS
ASSOCIATED WITH THE STRATUS SETTLES OVER THE NEW SNOW PACK WHERE
CONDITIONS HAVE ALREADY RADIATED.
.LONG TERM /TONIGHT THROUGH SATURDAY/...
OVERALL MID/LONG RANGE REMAINS RELATIVELY QUIET THROUGH THE
PERIOD...WITH MAINLY DRY CONDITIONS. ISSUE TONIGHT INTO
MONDAY...WILL BE IF STRATUS MOVING INTO THE CWA...WILL LINGER INTO
TONIGHT ACROSS THE AREA/BREAKUP/OR POSSIBLY EVEN REDEVELOP.
STRATUS/FOG HAS BEEN QUITE PERSISTENT ACROSS THE AREAS EAST OF THE
SFC HIGH PRES RIDGE SITUATED ACROSS THE CENTRAL DAKOTAS INTO NE/KS
THE PAST FEW DAYS...THEREFORE EXPECT THIS TREND TO CONTINUE TONIGHT.
THEREFORE HAVE INCREASED CLOUD COVER ACROSS THE SOUTHERN CWA
TONIGHT...AND ADDED IN A MENTION OF FOG AS HIGHER MOISTURE AIR
REMAINS IN PLACE OVER NEW SNOWPACK. OTHERWISE AS WINDS BECOME MORE
WESTERLY TO SOUTHWESTERLY AHEAD OF THE NEXT SYSTEM...EXPECT
CLOUDS/FOG TO ERODE ACROSS THE AREA MONDAY. TWO SYSTEMS OF NOTE
MONDAY INTO MONDAY NIGHT...WITH UPPER LEVEL SPLIT FLOW REGIME IN
PLACE. ONE STRENGTHENING UPPER LOW SITUATED ALONG THE FRONT RANGE OF
THE ROCKIES TUESDAY...EXPECTED TO SLIDE EAST INTO TUESDAY. ANOTHER
UPPER LEVEL SHORTWAVE DROPPING SOUTHEASTWARD FROM SASK/ALBERTA
THROUGH THE DAKOTAS/MN. THESE SYSTEMS TO MERGE OVER THE AREA TUESDAY
INTO TUESDAY NIGHT BRINGING INCREASING CLOUDS...AND POSSIBLY A
CHANCE FOR SOME LIGHT SNOW ACROSS THE SOUTHERN CWA. MAJORITY OF
PRECIPITATION EXPECTED TO FALL SOUTH OF IOWA...BUT SOUNDINGS TRY TO
SATURATE A BIT WITH WEAK LIFT ALONG AND SOUTH OF I-80. THEREFORE DID
EXPAND COVERAGE OF SLIGHT CHANCE POPS TO INCLUDE SOUTHERN HALF OF
CWA FOR TUESDAY...WITH THE SYSTEM QUICKLY SLIDING EAST/SOUTHEASTWARD
TUESDAY NIGHT WITH MAYBE SOME LINGERING SNOW ACROSS THE FAR
SOUTHEAST. OTHERWISE CAA EXPECTED THROUGHOUT THE DAY WITH
CLOUDS...SO EXPECT AN EARLY MAX TEMP WITH STEADY OR FALLING TEMPS
THROUGH THE REMAINDER OF THE DAY. HIGH PRESSURE TO BUILD INTO THE
AREA FOR WEDNESDAY...WITH BROAD UPPER LEVEL TROUGHING STILL EXPECTED
TO DIG SOUTHWARD ACROSS THE CENTRAL/EASTERN US FOR LATE IN THE WEEK.
THIS WILL BRING A COLD FROM SWEEPING THROUGH THE CWA
THURSDAY...SENDING H85 TEMPS INTO THE TEENS BELOW ZERO CELSIUS.
HOWEVER CANADIAN/GFS/PREVIOUS EC MUCH MORE AGGRESSIVE WITH THE SURGE
OF COLD AIR PLUNGING IT MUCH FURTHER SOUTH AND ALLOWING THIS ARCTIC
AIRMASS TO REMAIN IN PLACE ACROSS THE CWA FOR THE WEEKEND. LATEST
00Z EC IS MUCH DIFFERENT...KIND OF BRUSHING THE CWA WITH THE ARCTIC
AIRMASS AND THEN QUICKLY MODERATING THE TEMPS WITH WEAK UPPER
RIDGING INTO THE WEEKEND. THEREFORE SOME UNCERTAINTY WITH TEMPS
TOWARD THE END OF THE PERIOD...SO STUCK NEAR THE CONSALL GUIDANCE
GRIDS...WITH SOME TRENDING TOWARD THE COLDER SOLUTION DUE TO BETTER
CONTINUITY IN THE PAST FEW RUNS.
&&
.AVIATION...05/18Z
WIDESPREAD LIFR CONDITIONS IN STRATUS AND/OR FOG ACROSS IA LATE THIS
MORNING...ALTHOUGH GRADUAL IMPROVEMENT TO SPOTTY IFR IS OCCURRING.
THESE CLOUD TRENDS WILL BE THE BIGGEST CONCERN THROUGH THE
PERIOD...AND CONFIDENCE IS RATHER LOW. EROSION IS STARTING TO TAKE
PLACE ALONG SD/MN BORDER BUT QUESTION IS WHETHER THIS WILL BE
AGGRESSIVE ENOUGH TO REACH TAF SITES. HAVE CONTINUED PREVIOUS
THINKING KEEPING CIGS NO BETTER THAN IFR INTO MON MORNING...BUT
OUTCOMES ON EITHER END OF THAT CATEGORY ARE CERTAINLY POSSIBLE.
IMPROVEMENT IS MORE LIKELY NORTH /KFOD/KMCW/KALO/ WITH SOUTHERN
SITES IN FRESH SNOW COVER /DSM/KOTM/ MORE APT TO MIX LESS AND
STAY IN THE STRATUS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...DONAVON
LONG TERM...BEERENDS
AVIATION...SMALL
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1254 PM EST SUN FEB 05 2012
...Updated Aviation Discussion...
...1 PM Forecast Update...
Updated the forecast to extend light rain showers/drizzle over south
central KY into the tonight period through 3Z. Short range models
and upstream obs indicate this light precip on the eastern side of
the upper low. It is progged to pass through south central KY
between 21Z-3Z.
10 AM Forecast Update...
Updated the forecast this morning to remove fog wording from the
zones. Also, according to 12Z NAM and 12Z HRRR moisture/CIG
fields...it looks like low clouds may stick around a bit longer than
previously anticipated. The adjustment of clearing to the forecast
was only by an 1 or 2. Satellite trends this morning justify this
thinking. NE sections of our forecast area including Lexington will
be one of the first to see low clouds scatter out. No major temp
adjustments this morning. Highs still look to be limited to the mid
40s to around 50.
7 AM Forecast Update...
Drier air continues to slowly work southward as surface low over the
Carolinas departs to the east and surface trough swings through the
area. Some patches of dense fog and areas of low stratus have
developed this morning, although conditions should gradually improve
through the morning hours as the sun comes up and drier air
continues to work in. Issued a Special Weather Statement across
central Kentucky for the patches of dense fog through 9 AM EST. A
few patches of drizzle will also exist through midday, along with
the small chance that a light rain shower could measure. Otherwise,
temperatures will struggle today under northeasterly flow and slow
to clear clouds. Look for highs in the mid and upper 40s, but would
not be surprised to only see the mercury make it to the mid 40s.
&&
.Short Term (Today and Tonight)...
Surface low has moved east of the Appalachian spine to the North
Carolina/Virginia border. Meanwhile, upper low continues to spin
over the Kansas City region. Low clouds and patches of drizzle
remain over the area, along with patches of fog. Have left mention
of a slight chance of a measurable rain shower in the grids early
this morning, however think most locations will only see drizzle.
Temperatures will continue to drop into the upper 30s and low 40s
north of the parkways. Mid and upper 40s are expected across south
central Kentucky as winds have not shifted to northeasterly on the
warm side of a surface trough.
As we move through the daylight hours, surface low will move off the
Carolina Coast with upper low transitioning to an open wave. Expect
low clouds and slight chances of a measurable rain shower or drizzle
ahead of the nearly East/West oriented upper trough axis that
develops along the Ohio River to the eastern Plains. This axis will
gradually sink south along with deepest low level moisture, ending
chances of precipitation from north to south through the day. Skies
will also begin to clear out in the afternoon along and north of the
I 64 corridor. High temperatures are expected to struggle with cloud
cover for a good portion of the day along with northeasterly surface
flow. Look for highs mainly in the middle to upper 40s.
As we move into tonight, skies should be mostly clear as drier air
works into the region on continued northerly flow. Surface high will
be in control along with upper level ridging over the northern CWA.
Have patchy fog developing mostly in the sheltered valleys and in
southwestern Indiana under the upper level ridge. Think drier
airmass will keep fog from becoming more widespread, however will
have to monitor. Lows should dip into the lower 30s in most spots
with a few of the cool spots into the upper 20s.
.Long Term (Monday - Saturday)...
Slow-moving upper low in the short term will pick up steam toward
the east and clear the region during the day Monday. High pressure
building into the area will mean dry conditions at least through
Tuesday. Then from midweek on a series of upper level disturbances
will set up a large-scale trough over the Eastern U.S., bringing in
a more winter like cool down. None of the systems look overly wet
among the various long-term models. As the large-scale trough
becomes better established later in the day Friday, we may see a
band of precip come across, as per the latest GEM and GFS solutions.
GFS sounding indicates most of the layer will be below freezing,
except for a warmer surface. Previous forecast kept best chance,
only slight, in for Wednesday, then dry through the end of the
period. Will trim pops a little Wednesday and bump them up a little
Friday and Friday night, to slight chance over the east and
southeast, in line with the AllBlend. Both sets of periods will keep
as a rain/snow mix given forecast soundings and surface temperature
forecasts.
Speaking of temperatures, have readings starting off around 50 for
highs Monday, going up a few degrees over the south Tuesday, then
should be in the 40s all locations Wednesday and Thursday. The
cooler air will filter in Friday, with highs in the 30s over the
north. Then Saturday, all but south central Kentucky should remain
in the 30s for highs. Saturday morning should be the coolest of all
locations, with lows in the 20s.
&&
.Aviation (18Z TAF Issuance)...
An upper low over eastern MO this afternoon will move east to
eastern KY by tomorrow afternoon. This will allow a prolonged
period of low clouds this afternoon/evening for all TAF sites.
Although CIGS have slowly begun to lift, MVFR/IFR CIGs will continue
through at least 20Z. LEX will be the first to improve to VFR this
afternoon followed shortly by SDF and then BWG this evening. There
is a small chance that BWG may see another patch of drizzle this
evening, but radar imagery upstream indicates that drizzle is waning
and so will leave out of BWG TAF for now. Tonight, expect CIGS to
hang around at BWG through the early morning hours before
scattering. After CIGs scatter, some BR will be possible. The fog
forecast for BWG tonight has a moderate level of uncertainty due to
the timing on CIGS scattering and the passage of the upper low. For
SDF/LEX indicators are fairly clear that skies will clear this
evening and allow a long period of rad cooling overnight. This
should lead to at least IFR fog by morning...possibly lower. VSBYs
will improve starting around 14Z-15Z tomorrow.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS/BJS
Short Term.......BJS
Long Term........RJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1229 PM EST SUN FEB 05 2012
...Updated Aviation Discussion...
...10 AM Forecast Update...
Updated the forecast this morning to remove fog wording from the
zones. Also, according to 12Z NAM and 12Z HRRR moisture/CIG
fields...it looks like low clouds may stick around a bit longer than
previously anticipated. The adjustment of clearing to the forecast
was only by an 1 or 2. Satellite trends this morning justify this
thinking. NE sections of our forecast area including Lexington will
be one of the first to see low clouds scatter out. No major temp
adjustments this morning. Highs still look to be limited to the mid
40s to around 50.
7 AM Forecast Update...
Drier air continues to slowly work southward as surface low over the
Carolinas departs to the east and surface trough swings through the
area. Some patches of dense fog and areas of low stratus have
developed this morning, although conditions should gradually improve
through the morning hours as the sun comes up and drier air
continues to work in. Issued a Special Weather Statement across
central Kentucky for the patches of dense fog through 9 AM EST. A
few patches of drizzle will also exist through midday, along with
the small chance that a light rain shower could measure. Otherwise,
temperatures will struggle today under northeasterly flow and slow
to clear clouds. Look for highs in the mid and upper 40s, but would
not be surprised to only see the mercury make it to the mid 40s.
&&
.Short Term (Today and Tonight)...
Surface low has moved east of the Appalachian spine to the North
Carolina/Virginia border. Meanwhile, upper low continues to spin
over the Kansas City region. Low clouds and patches of drizzle
remain over the area, along with patches of fog. Have left mention
of a slight chance of a measurable rain shower in the grids early
this morning, however think most locations will only see drizzle.
Temperatures will continue to drop into the upper 30s and low 40s
north of the parkways. Mid and upper 40s are expected across south
central Kentucky as winds have not shifted to northeasterly on the
warm side of a surface trough.
As we move through the daylight hours, surface low will move off the
Carolina Coast with upper low transitioning to an open wave. Expect
low clouds and slight chances of a measurable rain shower or drizzle
ahead of the nearly East/West oriented upper trough axis that
develops along the Ohio River to the eastern Plains. This axis will
gradually sink south along with deepest low level moisture, ending
chances of precipitation from north to south through the day. Skies
will also begin to clear out in the afternoon along and north of the
I 64 corridor. High temperatures are expected to struggle with cloud
cover for a good portion of the day along with northeasterly surface
flow. Look for highs mainly in the middle to upper 40s.
As we move into tonight, skies should be mostly clear as drier air
works into the region on continued northerly flow. Surface high will
be in control along with upper level ridging over the northern CWA.
Have patchy fog developing mostly in the sheltered valleys and in
southwestern Indiana under the upper level ridge. Think drier
airmass will keep fog from becoming more widespread, however will
have to monitor. Lows should dip into the lower 30s in most spots
with a few of the cool spots into the upper 20s.
.Long Term (Monday - Saturday)...
Slow-moving upper low in the short term will pick up steam toward
the east and clear the region during the day Monday. High pressure
building into the area will mean dry conditions at least through
Tuesday. Then from midweek on a series of upper level disturbances
will set up a large-scale trough over the Eastern U.S., bringing in
a more winter like cool down. None of the systems look overly wet
among the various long-term models. As the large-scale trough
becomes better established later in the day Friday, we may see a
band of precip come across, as per the latest GEM and GFS solutions.
GFS sounding indicates most of the layer will be below freezing,
except for a warmer surface. Previous forecast kept best chance,
only slight, in for Wednesday, then dry through the end of the
period. Will trim pops a little Wednesday and bump them up a little
Friday and Friday night, to slight chance over the east and
southeast, in line with the AllBlend. Both sets of periods will keep
as a rain/snow mix given forecast soundings and surface temperature
forecasts.
Speaking of temperatures, have readings starting off around 50 for
highs Monday, going up a few degrees over the south Tuesday, then
should be in the 40s all locations Wednesday and Thursday. The
cooler air will filter in Friday, with highs in the 30s over the
north. Then Saturday, all but south central Kentucky should remain
in the 30s for highs. Saturday morning should be the coolest of all
locations, with lows in the 20s.
&&
.Aviation (18Z TAF Issuance)...
An upper low over eastern MO this afternoon will move east to
eastern KY by tomorrow afternoon. This will allow a prolonged
period of low clouds this afternoon/evening for all TAF sites.
Although CIGS have slowly begun to lift, MVFR/IFR CIGs will continue
through at least 20Z. LEX will be the first to improve to VFR this
afternoon followed shortly by SDF and then BWG this evening. There
is a small chance that BWG may see another patch of drizzle this
evening, but radar imagery upstream indicates that drizzle is waning
and so will leave out of BWG TAF for now. Tonight, expect CIGS to
hang around at BWG through the early morning hours before
scattering. After CIGs scatter, some BR will be possible. The fog
forecast for BWG tonight has a moderate level of uncertainty due to
the timing on CIGS scattering and the passage of the upper low. For
SDF/LEX indicators are fairly clear that skies will clear this
evening and allow a long period of rad cooling overnight. This
should lead to at least IFR fog by morning...possibly lower. VSBYs
will improve starting around 14Z-15Z tomorrow.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS/BJS
Short Term.......BJS
Long Term........RJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
400 PM EST SUN FEB 5 2012
LATEST UPDATE...ALL EXCEPT AVIATION...
.SYNOPSIS...(400 PM EST SUN FEB 5 2012)
FAIRLY QUIET WEATHER CONDITIONS WILL CONTINUE INTO EARLY THIS
WEEK...WITH A WARMER THAN NORMAL DAY EXPECTED MONDAY. AFTER SOME
MORNING CLOUDS...WE SHOULD SEE SUNSHINE THAT WILL BOOST TEMPERATURES
WELL INTO THE 40S. A COLD FRONT WILL SLIP SOUTH THROUGH THE STATE
MONDAY NIGHT WHICH WILL FILTER COLDER AIR IN FOR MID WEEK. LITTLE IN
THE WAY OF PRECIPITATION IS EXPECTED THROUGH THURSDAY. EVEN COLDER
AIR MOVES IN FOR LATE IN THE WEEK WITH SOME LAKE EFFECT SNOW SHOWERS
AS WELL. HIGHS WILL BE BACK DOWN IN THE 30S FOR MID WEEK AND IN THE
20S BY FRIDAY.
&&
.SHORT TERM...(400 PM EST SUN FEB 5 2012)
(TONIGHT THROUGH TUESDAY NIGHT)
CLOUDS HAVE BEEN THE FOCUS OF THE SHORT TERM FOR DAYS AND TODAY IS
NO EXCEPTION. A BATCH OF STRATUS IS LOCATED OVER LAKE MICHIGAN THIS
AFTERNOON...AND FEEL IT...ALONG WITH CLOUDS/MOISTURE UPSTREAM WILL
ADVECT INTO THE FORECAST AREA FROM THE WEST. ESSENTIALLY ENVISION A
GRADUAL EXPANSION TO THE EAST OF THE CLOUDS OVER THE LAKE AND POINTS
FURTHER WEST. RUC HAS SOMEWHAT OF A HANDLE ON THIS AND SEE NO REASON
TO ARGUE AT THIS POINT. THE STRATUS LATELY HAS BEEN PROBLEMATIC
THOUGH AND CONFIDENCE IS NOT HIGH IN ITS EVOLUTION. LOOKING FOR
MORNING CLOUDS TO LIFT WITH A FAIR AMOUNT OF SUNSHINE ON MONDAY.
HIGH SHOULD BE WELL ABOVE NORMAL IN THE 40S.
A COLD FRONT WILL DROP SOUTH THROUGH THE AREA MONDAY NIGHT. MOISTURE
DEPTH IS EXTREMELY SHALLOW...SO EXPECTING IT TO COME THROUGH FOR THE
MOST PART DRY. DO HAVE A FEW SNOW SHOWERS IN NORTHERLY FLOW ACROSS
THE NORTHWEST CORNER OF THE FORECAST AREA MONDAY NIGHT/TUESDAY
MORNING AS DELTA T/S CREEP ABOVE 13 DEGREES C. BY TUESDAY AFTERNOON
THOUGH THE FLOW IS TRENDING NORTHEAST/OFF SHORE. LOWER TROP DRIES
OUT FROM THE NORTH TUESDAY NIGHT DESPITE LAKE INSTABILITY. OVERALL
DRY CONDITIONS TUESDAY NIGHT WITH DECREASING CLOUDS.
&&
.LONG TERM...(400 PM EST SUN FEB 5 2012)
(WEDNESDAY THROUGH SUNDAY)
MAIN FOCUS OF THE FCST IN THE LONG TERM IS ON THE LAKE EFFECT
POTENTIAL FOR THE END OF THE WORK WEEK AND THE FIRST PORTION OF NEXT
WEEKEND.
IT APPEARS THAT WE SHOULD END UP IN BETWEEN SYSTEMS AT THE BEGINNING
OF THE LONG TERM ON WED. THERE WILL BE A SHORT WAVE MISSING THE AREA
TO THE SOUTH AND THERE WILL BE A WAVE THAT WILL BE GETTING READY TO
DROP SE ON THE SRN PERIPHERY OF THE POLAR VORTEX CENTERED ACROSS
HUDSON BAY. THIS WILL PLACE THE AREA UNDER SHORT WAVE RIDGING AND
DRY AND COOLER AIR.
THE MODELS ARE INDICATING THAT STRONG SHORT WAVE ENERGY COMING FROM
NRN CANADA SHOULD BE THE CAUSE FOR A COLD FRONT MOVING INTO THE AREA
LATER ON THU FROM THE NORTH. THIS WILL BE RESPONSIBLE FOR BRINGING
IN A GLANCING BLOW OF ARCTIC AIR TO THE AREA. H850 TEMPS WILL DROP
INTO THE NEGATIVE UPPER TEENS C. UPPER CYCLONIC FLOW WILL SETTLE IN
FOR FRI AND INTO SAT...AND WILL BRING THE POTENTIAL FOR LAKE EFFECT.
LAKE EFFECT PARAMETERS DO NOT LOOK FAVORABLE FOR A BIG EVENT.
MOISTURE DOES NOT LOOK VERY FAVORABLE MOST OF THE TIME...EXCEPT
MAYBE DECENT FRI MORNING. THERE IS EVEN POTENTIAL PER THE NEW 12Z
EURO WHERE THE FLOW WOULD END UP FROM THE NE...AND WE WOULD SEE
LITTLE IF ANY LAKE EFFECT. STILL A LOT OF DETAILS TO IRON OUT.
MODELS ARE ALL IN GOOD AGREEMENT IN THE CYCLONIC FLOW LIFTING OUT BY
SUN MORNING. THIS LOOKS TO OCCUR AS THE AMPLIFIED RIDGE OVER WRN
CANADA THAT HELPS TO SEND THE ARCTIC AIR DOWN GETS FLATTENED BY A
STRONG PACIFIC JET EXPECTED TO MOVE OVER THE PACIFIC NW. THIS SHOULD
SHIFT OUR FLOW TO A MORE MILD AND ZONAL PATTERN OFF OF THE PACIFIC
LATE NEXT WEEKEND.
&&
.AVIATION...(1254 PM EST SUN FEB 5 2012)
THE MAIN CHALLENGE WITH THE 18Z SET OF TERMINALS IS THE LOW CLOUD
COVER IN PLACE OVER THE REGION. A MVFR CLOUD DECK BASED AROUND
2000-2500 FT EXISTS NW OF A LINE FROM ROUGHLY KORD TO KMKG TO CLARE.
THIS CLOUD COVER IS LIKELY DUE TO SFC RIDGING OVER THE AREA LAST
NIGHT COMBINED WITH SOME MELTING SNOW. THE CLOUDS HAVE NOT BEEN
MOVING MUCH WITH A LIGHT WIND...AND THEY ARE STARTING TO MIX OUT
SOME. SOME DIURNAL CUMULUS IS DEVELOPING TOWARD KLAN...AND THIS
SHOULD BRING SOME TEMPO CIGS AROUND 2500 FT.
QUITE AN UNCERTAIN FCST RIGHT NOW...AND THE MODELS ARE STRUGGLING
WITH THE CURRENT PLACING OF THE CLOUD COVER. WE EXPECT SOME OF THESE
CLOUDS TO MIX OUT THROUGH DIURNAL PROCESSES...THOUGH HOW MUCH IS IN
QUESTION. THE CLOUDS TO OUR WEST SHOULD EVENTUALLY GET ADVECTED TO
THE EAST WITH AN INCREASING WRLY FLOW EXPECTED TO TAKE SHAPE THIS
EVENING. THIS FLOW COULD MIX THESE CLOUDS OUT...AND THERE ARE LITTLE
TO NO IMPACTS. THEY ALSO COULD GET ADVECTED IN BY THE WINDS...AND
PRODUCE MUCH MORE IMPACT. THE AREAS THAT WOULD BE AFFECTED THE MOST
WOULD BE KMKG AND KGRR...BUT WE CAN NOT RULE OUT THE OTHER TERMINALS
BEING AFFECTED. WE HAVE GONE SOMEWHAT OPTIMISTIC FOR NOW...AND JUST
HAVING A SCT025 DECK TONIGHT FOR THE NRN TERMINALS. AS TRENDS BECOME
MORE EVIDENT THROUGH THE AFTERNOON...WE CAN PIN DOWN THE DETAILS
WITH THE 00Z TERMINALS.
ONE OTHER THING TO MENTION IS W/SW WINDS WILL INCREASE MON MORNING
TO AROUND 12 KNOTS OR SO WITH SOME HIGHER GUSTS LIKELY.
&&
.MARINE...(400 PM EST SUN FEB 5 2012)
HOISTED A SMALL CRAFT ADVISORY FROM OVERNIGHT THROUGH THE DAY ON
MONDAY. WESTERLY WINDS PICK UP TONIGHT AHEAD OF A COLD FRONT THAT
WILL BE DROPPING SOUTH INTO THE GREAT LAKES REGION ON MONDAY. ONLY
RAN THE ADVISORY THROUGH MONDAY EVENING AT THIS POINT TO SEE EXACTLY
HOW THE WINDS ARE GOING TO PLAY OUT POST FROPA. IT APPEARS THOUGH
THAT THE ADVISORY WILL NEED TO BE EXTENDED INTO MONDAY NIGHT AND
TUESDAY AS WELL AS THE WAVE FIELD...EVEN IN NORTHEAST
FLOW...PROPAGATES INTO OUR NEARSHORE WATERS.
&&
.HYDROLOGY...(400 PM EST SUN FEB 5 2012)
RIVER FLOOD ADVISORIES FOR IONIA AND BURLINGTON HAVE BEEN DROPPED IN
THE PAST 24 HOURS...WITH VICKSBURG THE ONLY ONE REMAIN. LIMITED
HYDRO CONCERNS THE NEXT FEW DAYS WILL LITTLE IN THE WAY OF
PRECIPITATION EXPECTED.
RIVER ICE WILL LIKELY BECOME MORE OF A CONCERN FROM MID WEEK INTO
NEXT WEEKEND AS WE ARE FORECAST TO COOL OFF.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY ST. JOE TO MANISTEE OVERNIGHT THROUGH
MONDAY.
&&
$$
SYNOPSIS: DUKE
SHORT TERM: DUKE
LONG TERM: NJJ
AVIATION: NJJ
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1254 PM EST SUN FEB 5 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(402 AM EST SUN FEB 5 2012)
MILD WEATHER WILL CONTINUE TODAY AND MONDAY WITH HIGHS MAINLY IN THE
LOW TO MID 40S EACH DAY. IT WILL ALSO REMAIN DRY TROUGH MONDAY.
CHANGES WILL BEGIN MONDAY NIGHT AS A COLD FRONT BRINGS COOLER AIR
INTO THE REGION THAT WILL LAST INTO MID WEEK. TEMPERATURES WILL BE
CLOSER TO NORMAL VALUES FOR MID WEEK...HOWEVER ANY SNOWFALL WILL BE
LIMITED. ANOTHER COLD FRONT AND AN ENFORCING SHOT OF COLD AIR
SHOULD ARRIVE THURSDAY NIGHT AND LAST INTO NEXT WEEKEND. SOME LAKE
EFFECT SNOW SHOWERS ARE EXPECTED IN THIS COLDER REGIME.
&&
.SHORT TERM...(1140 AM EST SUN FEB 5 2012)
(TODAY THROUGH TUESDAY)
MADE SMALL MODIFICATIONS TO THE GOING FORECAST...SPECIFICALLY CLOUD
COVER IN THE NORTHWEST CORNER OF THE FORECAST AREA. IT APPEARS MOST
LOCATIONS ACROSS THE AREA WILL SEE MOSTLY SUNNY SKIES...THE
EXCEPTION BEING THE NORTHWEST TOWARD LUDINGTON. MODEL LOW LEVEL RH
IS NOT DOING A GOOD JOB DEPICTING THE STRATUS. THE RUC HAS A
CLUE...BUT IT IS NOT PINPOINTING AREAS THAT ARE MOSTLY CLOUDY
EITHER. IN GENERALLY HAVE A VERY SLOW EROSION OF THE CLOUD COVER UP
THERE THROUGH SUNSET...WHICH HAS YIELDED A MOSTLY CLOUDY WORDING IN
THE FAR NORTHWEST AND BECOMING PARTLY SUNNY ELSEWHERE. NOSED HIGH
TEMPS DOWN A TAD UP THERE AS WELL GIVEN THE CLOUDS.
PREVIOUS DISCUSSION FOLLOWS...
UNEVENTFUL WEATHER CONTINUES TONIGHT AND MONDAY. ABUNDANT SUNSHINE
ON MONDAY SHOULD BOOST TEMPS INTO THE 40S AGAIN.
CLOUDS WILL BE ON THE INCREASE MONDAY EVENING AS AN ARCTIC FRONT
DROPS SOUTH ACROSS THE CWA. MOISTURE LOOKS RATHER LIMITED INITIALLY
WITH THIS FRONT...SO ONLY EXPECTING TO SEE A FEW FLURRIES AS THE
FRONT COMES IN. TEMPS BEHIND THE FRONT FOR TUESDAY SHOULD ONLY
REACH THE UPPER 20S TO MID 30S...OR NEAR NORMAL VALUES. THE MODELS
ARE TRENDING TO SHOW DEEPER MOISTURE ARRIVING ALONG THE FRONT WITH A
SHORT WAVE CROSSING THE LOWER GREAT LAKES INTO TUESDAY. THIS STILL
DOES NOT LOOK OVERLY IMPRESSIVE...BUT AS THESE FEATURES COME
TOGETHER THE SOUTHERN HALF OF THE CWA COULD SEE A DUSTING OF SNOW ON
TUESDAY. HAVE ADDED LOW CHC POPS TO THIS AREA FOR NOW.
&&
.LONG TERM...(402 AM EST SUN FEB 5 2012)
(TUESDAY NIGHT THROUGH SATURDAY)
NO BIG STORMS IN THE EXTENDED BUT SOME SNOW SHOWERS ARE POSSIBLE AS
ARCTIC AIR RETURNS THURSDAY NIGHT AND FRIDAY.
MODELS HAVE TRENDED WEAKER AND FURTHER SOUTH WITH A WAVE ALONG THE
ARCTIC FRONT ON WEDNESDAY/WEDNESDAY NIGHT AND IT APPEARS THIS
FEATURE WILL NOT HAVE MUCH EFFECT ON THE LOCAL WEATHER. SNOW SHOWERS
SHOULD INCREASE BY THURSDAY AS CLIPPER MOVES ACROSS NORTHERN LOWER
MICHIGAN WITH CYCLONIC FLOW CONTINUING INTO FRIDAY. INVERSION
HEIGHTS ARE BELOW 10 KFT THROUGH THE EVENT SO A WIDESPREAD HEAVY
LAKE EFFECT SNOW IS NOT EXPECTED.
&&
.AVIATION...(1254 PM EST SUN FEB 5 2012)
THE MAIN CHALLENGE WITH THE 18Z SET OF TERMINALS IS THE LOW CLOUD
COVER IN PLACE OVER THE REGION. A MVFR CLOUD DECK BASED AROUND
2000-2500 FT EXISTS NW OF A LINE FROM ROUGHLY KORD TO KMKG TO CLARE.
THIS CLOUD COVER IS LIKELY DUE TO SFC RIDGING OVER THE AREA LAST
NIGHT COMBINED WITH SOME MELTING SNOW. THE CLOUDS HAVE NOT BEEN
MOVING MUCH WITH A LIGHT WIND...AND THEY ARE STARTING TO MIX OUT
SOME. SOME DIURNAL CUMULUS IS DEVELOPING TOWARD KLAN...AND THIS
SHOULD BRING SOME TEMPO CIGS AROUND 2500 FT.
QUITE AN UNCERTAIN FCST RIGHT NOW...AND THE MODELS ARE STRUGGLING
WITH THE CURRENT PLACING OF THE CLOUD COVER. WE EXPECT SOME OF THESE
CLOUDS TO MIX OUT THROUGH DIURNAL PROCESSES...THOUGH HOW MUCH IS IN
QUESTION. THE CLOUDS TO OUR WEST SHOULD EVENTUALLY GET ADVECTED TO
THE EAST WITH AN INCREASING WRLY FLOW EXPECTED TO TAKE SHAPE THIS
EVENING. THIS FLOW COULD MIX THESE CLOUDS OUT...AND THERE ARE LITTLE
TO NO IMPACTS. THEY ALSO COULD GET ADVECTED IN BY THE WINDS...AND
PRODUCE MUCH MORE IMPACT. THE AREAS THAT WOULD BE AFFECTED THE MOST
WOULD BE KMKG AND KGRR...BUT WE CAN NOT RULE OUT THE OTHER TERMINALS
BEING AFFECTED. WE HAVE GONE SOMEWHAT OPTIMISTIC FOR NOW...AND JUST
HAVING A SCT025 DECK TONIGHT FOR THE NRN TERMINALS. AS TRENDS BECOME
MORE EVIDENT THROUGH THE AFTERNOON...WE CAN PIN DOWN THE DETAILS
WITH THE 00Z TERMINALS.
ONE OTHER THING TO MENTION IS W/SW WINDS WILL INCREASE MON MORNING
TO AROUND 12 KNOTS OR SO WITH SOME HIGHER GUSTS LIKELY.
&&
.MARINE...(402 AM EST SUN FEB 5 2012)
A LIGHT NW WIND IS EXPECTED OVER THE LAKE TODAY. WAVES WILL BE ON
THE LOW SIDE. BUT BY LATE TONIGHT WEST WINDS WILL BE INCREASING
AHEAD OF THE ARCTIC FRONT. WE MAY NEED A SCA LATE TONIGHT OR AT
LEAST BY EARLY MONDAY TO ACCOUNT FOR THE INCREASING WINDS AND
WAVES. THE COLD ADVECTION BEHIND THE FRONT WILL LIKELY KEEP WAVES
ON THE HIGHER SIDE INTO MONDAY NIGHT.
&&
.HYDROLOGY...(402 AM EST SUN FEB 5 2012)
LIMITED HYDRO CONCERNS THROUGH THE SHORT TERM DUE TO MINIMAL PCPN.
SNOW MELT OVER THE NORTHERN CWA WILL CONTINUE...BUT THIS WILL NOT
PUSH RIVERS OUT OF THEIR BANKS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: JK
SHORT TERM: JK/DUKE
LONG TERM: OSTUNO
AVIATION: NJJ
MARINE: JK
HYDROLOGY: JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1247 PM EST SUN FEB 5 2012
UPDATED AVIATION DISCUSSION FOR THE 18Z TAFS
.SYNOPSIS... ISSUED AT 434 AM EST
00Z RAOBS SHOW DECAYING UPR LOW OVR KS/MO WHILE LARGER SCALE RIDGE
IS LOCATED FM WEST CONUS INTO WESTERN CANADA. PRIMARY TROUGHING IS
ORIENTED FM NORTHERN CANADA INTO QUEBEC AND NEW BRUNSWICK. COLDEST
AIR BY FAR IS LOCATED OVR FAR NORTHERN SECTIONS OF CANADA IN VCNTY
OF POLAR VORTEX. OTHERWISE...MOST OF CANADA AND THE CONUS FOR THAT
MATTER IS AWASH IN CONTINUAL FLOW OF MILD PACIFIC AIR. THIS WEEK
RIDGE IS EXPECTED TO BECOME MORE MERIDIONAL FM WESTERN CONUS INTO
ALASKA. RESULT IS EASTERN CANADA TROUGH TO SETTLE TOWARD GREAT LAKES
AND NORTHEAST CONUS. FIRST PUSH OF COOLER AIR ARRIVES ACROSS UPR
LAKES LATE MONDAY INTO TUESDAY. ANOTHER SHOT OF MUCH COLDER AIR IS
POSSIBLE LATE THIS WEEK INTO FIRST PART OF NEXT WEEKEND AS PORTION
OF POLAR VORTEX TRIES TO DISLODGE AND COME INTO THE CONUS. PATTERN
DOES NOT SUGGEST MUCH IN WAY OF OPPORTUNITY FOR LARGE SCALE WINTER
SYSTEMS. MAIN SNOWFALL THROUGH PERIOD WILL COME VIA LK EFFECT.
&&
.SHORT TERM /TODAY THROUGH MONDAY NIGHT/... ISSUED AT 434 AM EST
IN THE NEAR TERM...SFC RIDGE OVR PLAINS BEGINS TO EXPAND INTO UPR
LAKES. RUC13 HAS MUCH BETTER HANDLE ON CURRENT STRATUS THAN 00Z
NAM. PER RUC13 OUTPUT AND RAOBS...MOISTURE ADVECTION IN THE CLOUD
BEARING LAYER IS NEUTRAL SO EXPECT STRATUS BASED AROUND 925MB TO
PERSIST OVR CNTRL AND EASTERN CWA. TEMPS WILL REMAIN IN THE UPR 20S
TO LOWER 30S...EXCEPT STAYING IN THE TEENS OVR FAR WEST.
TODAY AND TONIGHT...EXPECT STRATUS TO CLEAR FM WEST TO EAST THIS
MORNING AS 925MB WINDS TURN WESTERLY ALLOWING LOWER 925MB DWPNTS TO
ADVECT INTO UPR LAKES. ONCE LOW CLOUDS DEPART...MIXING HEIGHTS BUILD
BENEATH MOSTLY SUNNY SKIES /THOUGH MAY SEE SCT-BKN MID CLOUDS INTO
EARLY AFTN NCNTRL AND EAST BASED ON CURRENT TRAJECTORIES OF CLOUDS
DROPPING ACROSS ONTARIO/. MODEL PROFILES FM BUFKIT INDICATE MIXING
ONLY TO 925MB BUT GIVEN EXPECTED INSOLATION...AND SEEING THAT LOW-
LEVELS MIXED AOA 900MB ON SATURDAY PER KGRB 00Z SOUNDING...WILL OPT
FOR MORE MIXING AND HIGHER TEMPS. BLEND OF 900MB-850MB MIXING HEIGHT
SUPPORTS HIGHS WELL INTO THE 40S AND MAYBE EVEN NEAR 50 DEGREES...
ESPECIALLY IN DOWNSLOPE AREAS OF CNTRL CWA /BARAGA TO MARQUETTE AND
SOUTH TO ESCANABA AND MENOMINEE/. BASED ON HOW WARM TEMPS WERE
YDY...MAY COME CLOSE TO THE RECORD HIGH OF 50 DEGREES FOR WFO
MARQUETTE /2005/. THE WARM DAY WILL TRANSLATE TO WELL ABOVE NORMAL
TEMPS FOR TONIGHT. WARMING WILL BE MOST PRONOUNCED NEAR LK SUPERIOR
SHORE WITH WEST WINDS STIRRING ALL NIGHT AHEAD OF COLD FRONT
APPROACHING FM THE NORTH. BASED ON UPSTREAM READINGS THIS MORNING
AHEAD OF COLD FRONT...WINDS MAY STILL BECOME LIGHT IN THE INTERIOR SO
KEPT LOWS AROUND 20F INLAND WEST.
MONDAY...COLD FRONT REACHES KEWEENAW BTWN 15-18Z...THEN SWINGS
THROUGH FM NORTH TO SOUTH THROUGH THE DAY OVR REST OF CWA. RETAINED
FALLING TEMP IDEA FM PREVIOUS SHIFT...ESPECIALLY OVER THE NORTH HALF
OF THE CWA IN THE AFTN. WEST FLOW AND H9 TEMPS NEAR 0C AHEAD OF FRONT
SHOULD ALLOW TEMPS OVR FAR SCNTRL TO CLIMB INTO THE LOW 40S AT KMNM...
BEFORE FALLING OFF INTO THE LOWER 30S LATE. TEMPS WILL FALL FM THE
LOWER 30S INTO THE LOWER 20S BY SUNSET OVR REST OF THE CWA. SEEMS
THAT PCPN CHANCES WILL BE FAIRLY LIMITED UNTIL MONDAY NIGHT. FCST
SOUNDINGS FM NAM/GFS SUGGEST INCREASING STRATOCU CLOUDS MORE THAN
ANYTHING ELSE. MOIST LAYER FCST TO REACH -10C LATE AFTN INTO EARLY
EVENING SO COULD SEE SNOW GRAINS OR FLURRIES LATE IN THE DAY OVR
HIGHER TERRAIN OF NW CWA.
MONDAY NIGHT...COOLING CONTINUES AT 925-850MB WITH FCST SOUNDINGS
INDICATING MOISTURE THROUGH AROUND 5KFT BY 06Z-12Z IN A WEAKLY
CYCLONIC NORTHERLY FLOW REGIME. UNIDIRECTIONAL FLOW THROUGH
850MB/5KFT WITH WIND SPEEDS LESS THAN 20 KTS SHOULD HELP LK EFFECT
ORGANIZE LATE EVENING INTO OVERNIGHT HOURS. DESPITE SUBSIDENCE/DRYING
ABOVE INVERSION AT H85...MAJORITY OF LAKE CONVECTIVE LAYER IS WITHIN
MOST IDEAL SNOW DENDRITIC GROWTH ZONE WITH TEMPS -12C TO -18C. ECMWF
IS ON THE WARM END WHILE CANADIAN INDICATES H85 TEMPS DOWN NEAR -20C
BY LATE MONDAY NIGHT. CERTAINLY HAVE SEEN MORE IMPRESSIVE LK EFFECT
SETUP BUT DOES SEEM THAT NRLY WINDS...LOW-LEVEL CONVERGENCE...AND
FAVORABLE MOISTURE WITHIN THE DGZ JUSTIFIES INCREASING POPS OVR FAR
WEST AND ALSO OVR MUCH OF MARQUETTE AND ALGER COUNTIES. A FEW INCHES
OF SNOW IS NOT OUT OF QUESTION MONDAY NIGHT AIDED BY HIGH SLR/S AND
INCREASING FLUFFINESS TO THE SNOW. EXPECT MINS INTO THE SINGLE
DIGITS OVR THE INTERIOR WEST WITH READINGS IN THE TEENS FOR OTHER
AREAS.
.LONG TERM /12Z TUE THRU SAT/...
TUE...ALTHOUGH A SHRTWV WL BE PUSHING THRU THE UPR GRT LKS ON TUE
MRNG FOLLOWING THE SHARP COLD FROPA MON NGT...LATEST MODELS RUNS
HAVE CONTINUED TREND TOWARD RISING HGTS SHARPLY IN THE AFTN WITH
VIGOROUS DNVA/DEEP LYR QVECTOR CNVGC/SUBSIDENCE IN THE WAKE OF THE
SHRTWV PASSAGE RESULTING IN SHARP ACYC FLOW BY 00Z WED. ONGOING LES
OVER MAINLY THE N WIND SN BELTS IN THE MRNG WITH H85 TEMPS FCST BTWN
-14C BY THE ECMWF TO AS LO AS -20C BY THE CNDN MODEL WL SUPPORT
LIKELY POPS IN THE FAVORED SN BELTS WITH INVRN HGTS ARND 4K FT AGL
AT 12Z. BUT THE SHSN WL TEND TO DIMINISH STEADILY THRU THE DAY
ESPECIALLY OVER THE W AS H85 TEMPS ARE FCST TO RISE UP AS HI AS -10C
BY THE ECMWF BY 00Z WED. THE 00Z GFS INDICATES THE STRONG SUBSIDENCE
WL CAUSE THE INVRN BASE TO SINK TO 2K FT AGL BY 00Z WED...ENDING ANY
SGNFT SHSN BY LATE IN THE DAY AS PWAT SINKS BLO 0.10 INCH.
TUE NGT...UNDER RISING HGTS...SHRTWV RDG IS PROGGED TO BLD SLOWLY
THRU THE UPR GRT LKS. WITH PWAT FCST AS LO AS 0.10 INCH/MOCLR SKIES
AND LGT WINDS...EXPECT TEMPS OVER THE INTERIOR SCNTRL TO SINK AOB
THE LO END OF GUIDANCE. READINGS NEAR LK SUP WL BE BUOYED A BIT BY A
STRONGER W WIND TO THE N OF THE SFC RDG AXIS ORIENTED THRU NRN WI
INTO NRN LWR MI.
EXTENDED...HI PRES RDG WL DROP INTO THE OH VALLEY ON WED WITH A DRY
WLY FLOW DOMINATING AND TEMPS A BIT ABV NORMAL. NEXT SHRTWV WL
IMPACT THE UPR LKS ON THU. THE 00Z GFS/CNDN MODELS ARE IN FAIRLY
GOOD AGREEMENT SHOWING A STRONGER DISTURBANCE/SFC LO MOVING THRU THE
UPR LKS. WHILE THE 12Z ECMWF RUN SHOWED A SIMILAR SCENARIO...THE 00Z
RUN HAS BACKED OFF ON THE INTENSITY OF THIS DISTURBANCE...CONTINUING
A TREND OF MODEL INCONSISTENCIES ON THE HANDLING OF THIS SHRTWV. SO
WENT NO HIER THAN CHC POPS FOR SN ON THU. WITH THE ARRIVAL OF COLDER
AIR IN THE WAKE OF THE SHRTWV PASSAGE /H85 TEMPS AS LO AS -26C PER
THE 00Z GFS BUT ONLY -20C PER THE ECMWF/... EXPECT LES MAINLY IN THE
NW WIND SN BELTS INTO FRI NGT. THE ARRIVAL OF HI PRES ON SAT WL
CAUSE THE LES TO DIMINISH. EXPECT TEMPS TO RUN AOB NORMAL THU NGT
INTO SAT.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
VFR CONDITIONS SHOULD PREVAIL AT KIWD/KCMX/KSAW THRU TONIGHT AS VERY
SHALLOW LOW-LEVEL MOISTURE IN THE REGION CONTINUES TO MIX OUT
GRADUALLY. HOWEVER...THERE IS SOME CONCERN THAT STRATUS/FOG IN MN
COULD HANG ON THRU THE AFTN AND THEN EXPAND EASTWARD UNDER WESTERLY
LOW-LEVEL WINDS AFTER SUNSET. WILL BE SOMETHING TO MONITOR THIS
EVENING. TIGHTER PRES GRADIENT BTWN HIGH PRES SINKING S THRU THE
PLAINS AND A COLD FRONT DROPPING S INTO NRN ONTARIO WILL RESULT IN
LLWS TONIGHT AS SFC WINDS WILL BE DECOUPLED. FAVORABLE WRLY FLOW MAY
KEEP WINDS GUSTY AT KCMX...SO LLWS LESS LIKELY THERE. COLD FRONT
WILL PASS THRU THE TAF SITES MON MORNING...BRINGING MVFR CLOUD DECK
AND PROBABLY SOME FLURRIES OR -SHSN.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
NORTHERLY WINDS TURN WEST AND INCREASE TO 30 KTS THIS AFTERNOON AND
EVENING AHEAD OF COLD FRONT DROPPING SOUTH ACROSS ONTARIO. MAY SEE
GALE GUSTS TO 35 KTS DUE TO COASTAL CONVERGENCE ALONG TIP OF
KEWEENAW PENINSULA. WINDS BECOME NORTHERLY ON MONDAY AFTERNOON IN
WAKE OF COLD FRONT. GALE GUSTS TO 35 KTS POSSIBLE MONDAY EVENING
OVER NORTH AND EAST...BUT THEN WINDS DIMINISH TO LESS THAN 25 KTS
LATER MONDAY NIGHT AS HIGH PRESSURE RIDGE QUICKLY BUILDS INTO UPR
LAKES REGION. A RISK OF HEAVY FREEZING SPRAY MONDAY NIGHT OVR
NORTHERN SECTIONS AS TEMPS DROP TOWARD ZERO.
THE ARRIVAL OF THE HI PRES RDG WILL CAUSE DIMINISING WINDS ON
TUE/TUE NIGHT...BUT A STRONGER WSW FLOW UP TO 25-30 KTS WILL DEVELOP
ON WED AS THIS RDG SINKS TO THE S. THE HIGHEST WINDS ARE MOST LIKELY
BETWEEN THE KEWEENAW AND ISLE ROYALE WHERE TERRAIN INFLUENCES TEND
TO ENHANCE THIS FLOW. FOLLOWING THE PASSAGE OF A LO PRES ON THU...
PLAN ON A STRONGER NNW FLOW OF COLDER AIR. THERE ARE MODEL
DIFFERENCES ON THE FORECAST INTENSITY OF THIS LO...AND GALES WOULD
NOT BE OUT OF THE QUESTION IF THE DEEPER SCENARIO VERIFIES. WITH THE
POTENTIAL ARRIVAL OF MUCH COLDER AIR...HEAVY FREEZING SPRAY MAY
IMPACT PORTIONS OF THE LAKE ON THU...ESPECIALLY THE NCENTRAL.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS...JLA
SHORT TERM...JLA
LONG TERM...KC
AVIATION...ROLFSON
MARINE...JLA/KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1140 AM EST SUN FEB 5 2012
LATEST UPDATE...SHORT TERM...
.SYNOPSIS...(402 AM EST SUN FEB 5 2012)
MILD WEATHER WILL CONTINUE TODAY AND MONDAY WITH HIGHS MAINLY IN THE
LOW TO MID 40S EACH DAY. IT WILL ALSO REMAIN DRY TROUGH MONDAY.
CHANGES WILL BEGIN MONDAY NIGHT AS A COLD FRONT BRINGS COOLER AIR
INTO THE REGION THAT WILL LAST INTO MID WEEK. TEMPERATURES WILL BE
CLOSER TO NORMAL VALUES FOR MID WEEK...HOWEVER ANY SNOWFALL WILL BE
LIMITED. ANOTHER COLD FRONT AND AN ENFORCING SHOT OF COLD AIR
SHOULD ARRIVE THURSDAY NIGHT AND LAST INTO NEXT WEEKEND. SOME LAKE
EFFECT SNOW SHOWERS ARE EXPECTED IN THIS COLDER REGIME.
&&
.SHORT TERM...(1140 AM EST SUN FEB 5 2012)
(TODAY THROUGH TUESDAY)
MADE SMALL MODIFICATIONS TO THE GOING FORECAST...SPECIFICALLY CLOUD
COVER IN THE NORTHWEST CORNER OF THE FORECAST AREA. IT APPEARS MOST
LOCATIONS ACROSS THE AREA WILL SEE MOSTLY SUNNY SKIES...THE
EXCEPTION BEING THE NORTHWEST TOWARD LUDINGTON. MODEL LOW LEVEL RH
IS NOT DOING A GOOD JOB DEPICTING THE STRATUS. THE RUC HAS A
CLUE...BUT IT IS NOT PINPOINTING AREAS THAT ARE MOSTLY CLOUDY
EITHER. IN GENERALLY HAVE A VERY SLOW EROSION OF THE CLOUD COVER UP
THERE THROUGH SUNSET...WHICH HAS YIELDED A MOSTLY CLOUDY WORDING IN
THE FAR NORTHWEST AND BECOMING PARTLY SUNNY ELSEWHERE. NOSED HIGH
TEMPS DOWN A TAD UP THERE AS WELL GIVEN THE CLOUDS.
PREVIOUS DISCUSSION FOLLOWS...
UNEVENTFUL WEATHER CONTINUES TONIGHT AND MONDAY. ABUNDANT SUNSHINE
ON MONDAY SHOULD BOOST TEMPS INTO THE 40S AGAIN.
CLOUDS WILL BE ON THE INCREASE MONDAY EVENING AS AN ARCTIC FRONT
DROPS SOUTH ACROSS THE CWA. MOISTURE LOOKS RATHER LIMITED INITIALLY
WITH THIS FRONT...SO ONLY EXPECTING TO SEE A FEW FLURRIES AS THE
FRONT COMES IN. TEMPS BEHIND THE FRONT FOR TUESDAY SHOULD ONLY
REACH THE UPPER 20S TO MID 30S...OR NEAR NORMAL VALUES. THE MODELS
ARE TRENDING TO SHOW DEEPER MOISTURE ARRIVING ALONG THE FRONT WITH A
SHORT WAVE CROSSING THE LOWER GREAT LAKES INTO TUESDAY. THIS STILL
DOES NOT LOOK OVERLY IMPRESSIVE...BUT AS THESE FEATURES COME
TOGETHER THE SOUTHERN HALF OF THE CWA COULD SEE A DUSTING OF SNOW ON
TUESDAY. HAVE ADDED LOW CHC POPS TO THIS AREA FOR NOW.
&&
.LONG TERM...(402 AM EST SUN FEB 5 2012)
(TUESDAY NIGHT THROUGH SATURDAY)
NO BIG STORMS IN THE EXTENDED BUT SOME SNOW SHOWERS ARE POSSIBLE AS
ARCTIC AIR RETURNS THURSDAY NIGHT AND FRIDAY.
MODELS HAVE TRENDED WEAKER AND FURTHER SOUTH WITH A WAVE ALONG THE
ARCTIC FRONT ON WEDNESDAY/WEDNESDAY NIGHT AND IT APPEARS THIS
FEATURE WILL NOT HAVE MUCH EFFECT ON THE LOCAL WEATHER. SNOW SHOWERS
SHOULD INCREASE BY THURSDAY AS CLIPPER MOVES ACROSS NORTHERN LOWER
MICHIGAN WITH CYCLONIC FLOW CONTINUING INTO FRIDAY. INVERSION
HEIGHTS ARE BELOW 10 KFT THROUGH THE EVENT SO A WIDESPREAD HEAVY
LAKE EFFECT SNOW IS NOT EXPECTED.
&&
.AVIATION...(623 AM EST SUN FEB 5 2012)
MVFR CLOUDS WERE SLOWLY ADVANCING SOUTH THROUGH LOWER MI OVERNIGHT
BUT MAY REMAIN NORTH OF KGRR AND KMKG TODAY. ADDED TEMPO GROUP FOR
MKG BUT KEPT GRR VFR FOR NOW AS THE LEADING EDGE OF THE CLOUDS MAY
BEGIN TO ERODE ONCE THE SUN COMES UP. ONLY ISOLATED MVFR FOG
EXPECTED THIS MORNING AND SHOULD DISSIPATE BY 15Z.
NORTH WINDS WILL GO WEST BUT REMAIN BELOW 10 KNOTS TODAY.
&&
.MARINE...(402 AM EST SUN FEB 5 2012)
A LIGHT NW WIND IS EXPECTED OVER THE LAKE TODAY. WAVES WILL BE ON
THE LOW SIDE. BUT BY LATE TONIGHT WEST WINDS WILL BE INCREASING
AHEAD OF THE ARCTIC FRONT. WE MAY NEED A SCA LATE TONIGHT OR AT
LEAST BY EARLY MONDAY TO ACCOUNT FOR THE INCREASING WINDS AND
WAVES. THE COLD ADVECTION BEHIND THE FRONT WILL LIKELY KEEP WAVES
ON THE HIGHER SIDE INTO MONDAY NIGHT.
&&
.HYDROLOGY...(402 AM EST SUN FEB 5 2012)
LIMITED HYDRO CONCERNS THROUGH THE SHORT TERM DUE TO MINIMAL PCPN.
SNOW MELT OVER THE NORTHERN CWA WILL CONTINUE...BUT THIS WILL NOT
PUSH RIVERS OUT OF THEIR BANKS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...NONE.
&&
$$
SYNOPSIS: JK
SHORT TERM: JK/DUKE
LONG TERM: OSTUNO
AVIATION: OSTUNO
MARINE: JK
HYDROLOGY: JK
AREA FORECAST DISCUSSION...UPDATED FOR 18Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1140 AM CST SUN FEB 5 2012
.AVIATION.../18Z TAF ISSUANCE/
WDSPRD IFR TO LIFR CONDS CURRENTLY AT ALL TAF SITES. LEADING EDGE
OF THESE CONDS HAS BEEN SNEAKING TOWARD EAU ALL MORNING AND WITHIN A
FEW MILES OF AIRPORT NOW. MAY BE A PERIOD FOR A COUPLE HOURS OF IFR
CIGS AT EAU BEFORE SUN SCATTERS CLOUDS. ACROSS WESTERN MINNESOTA
THERE HAS BEEN AN EROSION OF CLOUDS/FOG LAST HOUR OR SO. EXPECT
CLEARING WITH HELP OF SOME DOWNSLOPE WLY WINDS TO IMPROVE TO VFR AT
RWF WITHIN NEXT COUPLE OF HOURS. AXN HAS ALSO BEEN IMPROVING AND
SHUD BECOME VFR BY 21Z. VSBL SATL SHOWS CLOUDS ACROSS ABOUT N 1/2 OF
MN VERY THIN WITH LAKES SHOWING THRU CLOUDS ALL MORNING AND NICE
HOLES OPENING UP RECENTLY. THIS SHOULD WORK INTO STC MID AFTN. THE
LAST TO IMPROVE SHUD BE MSP/RNH. PIREPS SHOW CLOUDS ARND 2K THICK
AND 12Z MPX RAOB HAS NOTICEABLY DEEPER MOIST LAYER THAN
YESTERDAY...BUT SHUD IMPROVE TO MVFR ARND 20-21Z AND THEN REMAIN SO
INTO EVENING. SOME THREAT OF STRATUS REFORMING AGAIN
TONIGHT...MAINLY ACROSS WC WI INTO E MN. CDFNT PASSAGE WILL SWEEP
OUT ANY REMAINING IFR CONDS MONDAY MRNG/ERLY AFTN IMPROVING TO MVFR
CIGS.
KMSP...IFR CIGS SHOULD IMPRV TO MVFR CIGS 20-21Z...BUT FURTHER
IMPROVEMENT WILL LIKELY BE SLOW WITH CLOUDS THICKER THAN YESTERDAY.
MAY SEE A PERIOD OF VFR DURING THE EVENING WITH THREAT OF IFR
STRATUS DEVELOPING AGAIN IN THE OVERNIGHT. CDFNT PASSAGE MID DAY
MONDAY WILL BRING AN END TO THE IFR CONDS OF PAST 5 DAYS. EXPECT
MVFR CIGS IN WAKE OF CDFNT...IMPROVING TO VFR MONDAY EVENING.
&&
.DISCUSSION...
THE FORECAST CONCERN IN THE NEAR TERM REMAINS THE STRATUS OVER THE
REGION ONCE AGAIN THIS MORNING. SOUTHEAST MOVEMENT OF CLOUD DECK
SHOULD ENVELOP ALL OF MINNESOTA PORTION OF THE REGION. HRRR TRENDS
INDICATE NORTHEAST WISCONSIN CLOUDS TO WORK SOUTHWEST INTO THAT
REGION DURING THE MORNING. VSBYS NOT ALL THAT BAD THIS AM...WITH
MOST AREAS ABOVE 2SM. DOES APPEAR MORE WEST/SOUTHWEST FLOW
DEVELOPING AHEAD OF NEXT COLD FRONT SHOULD BE ENOUGH TO MIX OUT
THE STRATUS OVER THE NORTHWEST PORTION OF THE AREA THIS AFTERNOON.
WILL MENTION PARTLY CLOUDY DEVELOPING IN THE SOUTHEAST...AS
CONFIDENCE NOT HIGH ON STRATUS TOTALLY CLEARING OUT. SHOULD SEE
TEMPERATURES WARM THROUGH THE 30S INTO THE 40S WHERE CLOUDS CLEAR
FASTEST TODAY.
COLD FRONT DROPS INTO NORTHERN MINNESOTA OVERNIGHT TONIGHT. WITH
SOUTHWEST FLOW DEVELOPING SHOULD SEE TEMPERATURES STAY UP A BIT
OVERNIGHT. COULD SEE A TOUCH OF FOG OVER WESTERN WI THIS
EVENING...BUT WILL LIKELY IMPROVE AFTER MIDNIGHT IF IT DOES
DEVELOP...AS FRONT/PRESSURE GRADIENT SAGS INTO THE AREA. TEMPERATURES
SHOULD START OUT RATHER WARM MONDAY AND SHOULD SEE SOME UPPER 40S
AGAIN IN THE FAR SOUTH BEFORE FROPA IN THE AFTERNOON. CLOUDS MAY
HOLD OFF UNTIL EVENING OVER MUCH OF THE AREA...BUT DO EXPECT THEM
AROUND MUCH OF MONDAY NIGHT. MAY EVEN SEE A FLURRY OR TWO.
FLOW PATTERN APPEARS TO BE IN TRANSITION AGAIN AS WESTERN BLOCK
REMAINS. GFS AND GEM TREND AM AMPLIFICATION OF THE EASTERN CONUS
TROUGH WITH THE GFS THE MOST AMPLIFIED/COLDEST. THE 00Z ECMWF
CONTINUES ITS TREND OF DIVING SOME TROUGH ENERGY SOUTH OVER THE
EASTERN CONUS THROUGH THE WEEK BUT THE WESTERN BLOCK IS ERODED
WEST LATE IN THE WEEK WITH A MORE ZONAL TYPE FLOW PATTERN
DEVELOPING INTO THE HE WEEKEND. EXTENDED DISCUSSION DID MENTION
THEY DID NOT LIKE THE ECMWF TREND...AND THEY HELD ONTO THE EASTERN
CONUS TROUGH A BIT LONGER. THIS DOES SPELL COLDER THAN NORMAL FOR
LATE IN THE WEEK. AT THE MOMENT...PERIOD IS DRY...BUT THERE MAY BE
A FEW SNOW SHOWERS/FLURRIES...MAINLY EAST...AS COLDEST AIR
ARRIVES THURSDAY INTO FRIDAY.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
DWE/BAP
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
200 PM CST SUN FEB 5 2012
.DISCUSSION...
Today we casually celebrate "National Weatherperson`s Day", which I
suppose is a bit self-gratifying. However, none of these
discussions, our forecasts, or warnings would be effective if it
were not for the media, emergency managers, observers and storm
spotters who make our jobs that much easier. So here`s to you Mr.
Gabrielson for all the help you`ve given me and the rest of the NWS
over the past few years.
Tonight: On the home front, most of the CWA has experienced abundant
sunshine in the wake of the storm system that dumped beneficial
rainfall and some snow across the region over the past two days.
Visibile satellite imagery shows the light snow cover has eroded
rapidly back toward extreme NW MO, which itself has disguised an
expansive canopy of low stratus that has blanketed eastern Nebraska
and most of Iowa today. This deck has crept southward into far nrn
MO over the past several hours, but with the loss of daytime heating
I would expect a fairly rapid expansion toward the south and east
this evening focused along the eastern half of the approaching
surface ridge axis. To further complicate matters tonight, the very
moist boundary layer, coupled with light winds and clear skies would
tend to promote a fairly healthy environment for dense freezing fog
along the periphery (or within) the stratus shield. A combination of
LIFR ceilings and fog will impact both aviation and ground travel
interests across northern and eastern Missouri overnight.
Tomorrow: A rather benign day once the fog burns off with southwest
winds returning early in the day. Should warm up to around 50 most
locations, with the exception of far NW MO where lingering light
snow cover will have some influence.
Tuesday-Wednesday: Western extension of yesterday`s storm has since
closed off over the Central Rockies and will finally begin to emerge
late Monday. This secondary gyre will gradually lose its closed
character as it opens and phases with a stronger wave dropping south
from Canada. Collectively, these systems will allow some colder air
to filter into the area Wednesday, but the accompanying
precipitation event looks anything but impressive, driven mainly by
system scale mid level ascent. Cloud cover should arrive pre-dawn
Tuesday, with a fairly broad area of light snow (northwest) to
rain (southeast) developing and persisting through early evening.
Outside of some localized enhancement, expect amounts generally
less than a tenth of an inch with little or snow snow accums.
Thursday-Saturday: Region will reside in the void between the polar
and subtropical streams with the dominant polar vortex undergoing
strong intensification over Hudson Bay with a powerful cyclonically
curved polar jet traversing its circumference. Building heights
along the west coast will keep the bulk of Pacific energy offshore
with a secondary area of troughing along the TX/MX border region.
For us, this will yield a prolonged period of dry weather with
little change in temperatures -- in fact one of the cooler periods
we`ve seen in some time.
Sunday and beyond: It appears enough shortwave impulses across the
northern Pacific will break down the western ridge yet again, while
phasing streams over the eastern states allow the longwave to shift
into the Atlantic. Thus, the trend for Sunday into early next week
should be for a return to more zonal flow with warmer conditions
moving back into the area.
Bookbinder
&&
.AVIATION...
VFR conditions continue across the terminals late this morning with
a light northwest wind. Continue to watch an extensive area of LIFR
stratus and fog that continues to drift south into far northern
Missouri. HRRR and other fine scale model output shows this deck
getting very close to STJ by 20Z, but the decreasing snow cover and
abundant sunshine to the south should put an end to the stratus
push.
Winds will diminish quickly tonight, and the very moist boundary
layer along the periphery of this stratus deck, coupled with melting
light snow cover, appears very conducive to freezing fog development
overnight. KSTJ looks like a prime target for dense fog by 09Z, and
would not be surprised to see KMCI follow suit -- initialized with
low IFR there.
Any fog should mix out by 14-15Z as winds steady from the southwest
at 6-8 knots.
Bookbinder
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION...UPDATED AVIATION
NWS ST LOUIS MO
1237 PM CST SUN FEB 5 2012
.DISCUSSION...
/255 AM CST SUN FEB 5 2012/
THE SHORT TERM FORECAST OVER THE NEXT 12 HOURS POSES THE BIGGEST
CHALLENGES OVER THE NEXT SEVERAL DAYS. THE FEATURE OF CONCERN IS
THE UPPER LOW FORECAST TO DROP SEWD THROUGH THE AREA TODAY AND THE
ASSOCIATED IMPACTS. PROFILER AND VWP DATA SHOW THAT THE UPPER LOW
HAS PASSED JUST SE OF KANSAS CITY. THE VAST MAJORITY OF PRECIPITATION
THUS FAR HAS ACTUALLY BEEN TO THE NORTH OF THE LOW CENTER...AND
HAS BEEN ROTATING SOUTHWESTWARD ABOUT THE CIRCULATION. NEAR AND
NORTH OF THE LOW ARE THE ONLY LOCATIONS THAT HAVE REPORTED ANY
SNOW THUS FAR AS WELL. CURRENTLY TO THE EAST OF THE LOW ACROSS
EASTERN MO...BANDS OF RAIN SHOWERS HAVE DEVELOPED WITHIN THE LAST
FEW HOURS WITHIN WHAT APPEARS TO BE A REGION OF MID LEVEL QG
FORCING. TEMPERATURES WITHIN THIS AREA RANGE FROM THE UPPER 30S TO
LOWER 40S. THE RUC APPEARS TO HAVE THE BEST HANDLE ON THE TRACK OF
THE UPPER LOW AT THIS TIME...TRACKING IT TO NEAR THE LAKE OF THE
OZARKS REGION BY 18Z. THEREAFTER THE MAJORITY OF THE MODELS WOULD
SUGGEST IT WILL CONTINUE TO TRACK SEWD AND INTO SE MO THIS
AFTERNOON AND THEN EXIT INTO THE WESTERN TN VALLEY TONIGHT. BASED
ON THIS LOW TRACK AND THE ASSOCIATED QG FORCING TO THE EAST...EXPECTING
CHANCE POPS/SCATTERED SHOWERS/DRIZZLE TO IMPACT THE AREA FROM
COU-STL-SLO SOUTHWARD. I AM NOT VERY EXCITED ABOUT THE PROSPECTS
OF ANY SNOW AND GIVEN ONLY SLIGHTLY COOLER TEMPERATURES EARLY THIS
MORNING THAN NOW...I WOULDN`T EXPECT ANY ACCUMULATION IF WE DID
SEE SOME. BY THIS AFTERNOON THE POP THREAT SHOULD BE CONFINED TO
FAR SE MO. STRATUS WILL SLOWLY CLEAR SOUTH THROUGH THE DAY AS
WELL.
WEAK HIGH PRESSURE WILL DOMINATE THE REGION TONIGHT WITH
SEASONABLY CHILLY TEMPERATURES. WESTERLY LOW LEVEL FLOW AND WARM
ADVECTION THEN GETS GOING ON MONDAY AND TEMPERATURES WILL ONCE
AGAIN BE ABOVE AVERAGE. THE NEXT SHOT OF COLD AIR LOOKS ON TRACK
FOR TUESDAY AS A NORTHERN STREAM SHORT WAVE TROF DIGS SOUTHEAST
INTO THE UPPER MIDWEST AND INTERACTS WITH THE REMNANT GREAT BASIN
UPPER LOW. WE CURRENTLY HAVE POPS JUST BELOW THRESHOLDS THAT ARE
MENTIONED IN THE FORECAST FOR THIS SYSTEM. THERE IS AND HAS BEEN
QUITE A BIT OF VARIABILITY WITH THE PRECIPITATION CHANCES...AND
CONFIDENCE IS LOW AT THIS TIME. ANYWAY THIS SHOT OF COLD AIR WILL BE A
GLANCING SHORT-LIVED BLOW BRINGING TEMPERATURES BACK DOWN TO
SEASONABLE NORMS TUESDAY NIGHT-WED NIGHT.
THE LONGER RANGE GUIDANCE...WHILE SHOWING SOME DETAIL DIFFERENCES
...IS TRENDING TOWARDS TEMPERATURES MORE WINTER-LIKE BY THE END
OF THE UPCOMING WEEK. THE GENERAL IDEA AT THIS JUNCTURE IS A DEEP
VORTEX WILL BECOME ESTABLISHED NEAR HUDSON BAY WITH A DEEP FULL
LATITUDE TROF EXTENDING TO THE SOUTH INTO THE EASTERN U.S.. THE
ORIENTATION OF THIS TROF AND INTENSITY/LONGEVITY OF THE COLD AIR
ARE WHERE THE MODELS DIFFER WITH THE GFS SHOWING POTENTIAL FOR
SOME OF THE COLDEST AIR THIS SEASON.
GLASS
&&
.AVIATION...
/1203 PM CST SUN FEB 5 2012/
UPPER LEVEL LOW WAS BETWEEN COU AND STL EARLY THIS AFTN WITH THE
CLEARING LINE MOVING S OF COU AND ABOUT TO DROP S OF THE STL METRO
AREA...ALTHOUGH THERE WAS A LITTLE DIURNAL CUMULUS OR STRATOCUMULUS
CLOUDS DEVELOPING. DESPITE THIS STL...SUS AND CPS SHOULD BE VFR
THIS AFTN WITH ONLY SCT CLOUDS LEFT BY MID-LATE AFTN. MORE OF A
CONCERN IS THE VERY LOW LEVEL STRATUS DECK ALONG WITH FOG ACROSS
IA WHICH WAS ADVECTING SWD INTO NERN MO. THIS CLOUD MASS IS NOT
HANDLED WELL BY THE MODEL GUIDANCE. ALTHOUGH THE EDGES OF THIS
CLOUD MASS MAY DISSIPATE THIS AFTN WITH DIURNAL HEATING IT APPEARS
THAT IT WILL MOVE INTO UIN BETWEEN 19-20Z SUN...AND MAY ALSO MAKE
IT DOWN TO THE REST OF THE TAF SITES THIS EVNG. FOR NOW WILL
INCLUDE A BKN-OVC CLOUD DECK IN THE UIN TAF BEGINNING AT 20Z SUN
ALONG WITH SOME FOG...THEN SCT THE CEILING OUT MON MRNG AS A WLY
WIND ADVECTS THIS CLOUD MASS E OF THE AREA. DUE TO THE UNCERTAINTY
OF THE CLOUD FORECAST AND THE POOR MODEL PERFORMANCE WILL JUST
INCLUDE SCT LOW LEVEL CLOUDS FOR THE REST OF THE TAF SITES FOR TGT
ALONG WITH LIGHT FOG. NLY SFC WINDS WILL CONTINUE THIS AFTN WITH THE
SFC RIDGE OVER THE PLAINS...THEN BECOME LIGHT THIS EVNG...AND WLY
ON MON AS THE SFC RIDGE SHIFTS SW OF OUR AREA.
SPECIFICS FOR KSTL...THE VFR CLOUDS SHOULD CLEAR OUT LATER THIS
AFTN. MUCH UNCERTAINTY IF THE STRATUS CLOUD DECK OVER IA WILL
MAKE IT DOWN AS FAR S AS STL OR MIX OUT...DISSIPATE BEFORE IT
GETS TO STL. FOR NOW WILL JUST INCLUDE SCT010 CLOUDS TGT ALONG
WITH LIGHT FOG FOR MAINLY LATE TGT AND EARLY MON MRNG. NLY SFC
WIND WILL CONTINUE THIS AFTN...THEN BECOME LIGHT THIS EVNG...AND
WLY BY LATE MON MRNG.
GKS
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
IL...NONE.
&&
$$
WFO LSX
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1132 AM CST SUN FEB 5 2012
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
Today - Tonight:
The upper low that has affected the region over the last few days
continues to weaken as it spins over northwestern Missouri. Warming
cloud top temperatures per IR satellite, decreasing radar returns and
increasing ceilings and visibilities all confirm the weakening of the
system. This trend will continue as the low slides southeast into
central Missouri and any remaining precipitation will be confined to
the vicinity of the low so have added low pops through our
southeastern zones to account for this. Any precipitation should be
out of the forecast area by mid to late morning so have kept the
afternoon period dry.
Outside of the lingering precipitation chances, today`s cloud
forecast is rather difficult. The clouds associated with the upper
low should move south and east/erode through the day. But 11-3.9u
satellite imagery reveals an area of very low stratus and fog moving
southward through Iowa and Nebraska. There may be a period of time
this morning when northern Missouri clears completely out and
coupled with recent snow across the far northwest corner of the
state could have dramatic effects on our temperatures due to
radiational cooling around sunrise. I am not overly confident on the
timing of either cloud element in our north so have tended to play
the middle ground with regards to temperatures there. Models have
very poor handling of the low stratus but see no reason why it won`t
progress southward into northern Missouri by mid morning or so,
further limiting any warm up in that part of the forecast area.
For tonight, while quiet weather is expected, models continue to
struggle with the effects of the new snow cover to our north and
northwest. The latest SREF visibility and ceiling probability
forecast indicate an increasing potential for low clouds and lower
visibilities across our north. Have therefore added a mention of fog
across northern Missouri as this makes conceptual sense given the
moist and cool boundary layer.
Monday:
Quiet weather is expected for this period as the upper level energy
that brought the region snow has been split apart, with one piece
heading east and another that has gotten cutoff within the upper
ridge over western North America. Mostly clear/clear skies are
expected and we should be able to warm back into the mid to upper 40s
for most locations and even a few 50 degree readings are possible in
our southern zones.
Monday Night - Tuesday:
The above mentioned cutoff portion should begin to eject eastward
through the Central Plains, aided by another wave diving southward
out of Canada. This will bring a chance for precipitation across the
forecast area by mid day Tuesday and with a very strong, 1040mb high
pressure surging down the Plains behind the Canadian system, enough
cold air will be move into the region bring a chance for light snow
to the forecast area. The GFS seems to the most robust with this
system with other models offering up a weaker system with less QPF.
So this system will need to be watched for the potential for light
accumulating snow. Temperatures Tuesday may not budge much from
overnight lows, especially across northern Missouri, given the cloud
cover and warm advection and highs in the lower 30s are expected
across that part of the forecast area.
Wednesday - Sunday:
Dry weather is expected to prevail through the extended period. With
a ridge developing over the western CONUS and deep troughing over
the east persisting into the later half of the week, we should see
northwesterly flow across the Central Plains. This should keep us
close to or just above normal for most the period with the possible
exception of Friday, when a colder airmass moves into the eastern
Plains/Midwest in response to the deepening eastern trough. There is
quite a bit of spread amongst the models, both deterministic and
ensembles, with how deep the trough digs but by the end of the
weekend, flow should become less amplified and a return to above
normal temperatures is expected.
CDB
&&
.AVIATION...
VFR conditions continue across the terminals late this morning with
a light northwest wind. Continue to watch an extensive area of LIFR
stratus and fog that continues to drift south into far northern
Missouri. HRRR and other fine scale model output shows this deck
getting very close to STJ by 20Z, but the decreasing snow cover and
abundant sunshine to the south should put an end to the stratus
push.
Winds will diminish quickly tonight, and the very moist boundary
layer along the periphery of this stratus deck, coupled with melting
light snow cover, appears very conducive to freezing fog development
overnight. KSTJ looks like a prime target for dense fog by 09Z, and
would not be surprised to see KMCI follow suit -- initialized with
low IFR there.
Any fog should mix out by 14-15Z as winds steady from the southwest
at 6-8 knots.
Bookbinder
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
316 PM CST SUN FEB 5 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
A LULL IN WEATHER ACTIVITY WILL KEEP THE AREA QUIET THROUGH
TOMORROW. SUBJECTIVE 12Z UPPER AIR ANALYSIS INDICATES UPPER LOW
CUTTING OFF OVER THE GREAT BASIN FROM AN ELONGATED EAST-WEST TROUGH
AXIS...WITH AN UPPER HIGH CENTERED AROUND SOUTHERN AB/SASK/MB.
STRONG UPPER-LEVEL SHORTWAVE WAS DESCENDING OUT OF THE NW
TERRITORIES INTO NORTHERN AB/SASK. COLD AIR REMAINS LOCKED WELL
NORTH AND EAST OF THE CENTRAL US...WITH AN 850MB COLD POOL CENTERED
OVER KS/OK UNDER THE UPPER TROUGH...AND A WARM POOL OVER
SASK/MB/ND/MT UNDER THE UPPER HIGH THAT WAS DROPPING INTO THE
CENTRAL US.
MAIN FORECAST CONCERNS INCLUDE STRATUS/FOG THROUGH TONIGHT...AND
LIGHT SNOW POTENTIAL ON TUESDAY. MODELS ARE NOT HANDLING THE
SHALLOW STRATUS DECK WELL...BUT HRRR DOES HAVE A GOOD HANDLE ON THE
CURRENT EXTENT OF THE STRATUS AND FOG...AND RUC IS IN THE BALLPARK.
BOTH KEEP THE STRATUS LOCKED IN ROUGHLY ALONG AND EAST OF THE
MISSOURI RIVER THROUGH THE NIGHT...ALONG WITH DEVELOPING/KEEPING FOG
IN ROUGHLY THOSE AREAS OVERNIGHT. GIVEN AMPLE LOW-LEVEL
MOISTURE...LACK OF ANY KIND OF COLD AIR PUSH OR ADVECTION THAT WOULD
SCOUR THE MOISTURE...AND PERSISTENCE THROUGH THE DAY...AM INCLINED
TO LEAN PESSIMISTIC AND KEEP THE FOG/STRATUS OVERNIGHT. HAVE
INCLUDED A RATHER SHARP GRADIENT FROM OVERCAST TO CLEAR...WITH SOME
WESTWARD EXPANSION THROUGH THE NIGHT. NATURALLY...TEMPERATURES WILL
DEPEND STRONGLY ON LOCATION OF CLOUDS. FOR NOW...HAVE KEPT AREAS
WEST OF A LINE FROM AROUND LINCOLN TO WAYNE CLEAR...AND THUS MUCH
COLDER...THAN AREAS EAST.
DID ALLOW FOR CLOUDS TO SCOUR OUT IN THE MORNING HOURS TOMORROW AS
WEST WINDS INCREASE A BIT...THOUGH CONFIDENCE IS LOW IN THE TIMING
OF THIS. SHOULD SEE SOME MODERATION WITH WARM AIR ADVECTION AND
LIGHT MIXING DURING THE DAY...THOUGH INCREASING HIGH-LEVEL CLOUDS
LATER IN THE DAY MAY HINDER FULL SUNSHINE. COLD FRONT ASSOCIATED
WITH THE SHORTWAVE CURRENTLY LOCATED IN NORTHERN CANADA WILL DROP
THROUGH ON MONDAY NIGHT. NORTHERN STREAM WAVE AND SOUTHERN STREAM
WEAKENING/EJECTING UPPER LOW ARE PROGGED TO PHASE AS THE TWO
INTERACT OVER THE CENTRAL PLAINS...AND THE RESULTING UPPER-LEVEL
TROUGH WILL GENERATE AN AREA OF PRECIPITATION OVER KS/MO BEGINNING
LATE MONDAY NIGHT. SOUTHERN CWA LIKELY WILL BE JUST ON THE NORTHERN
FRINGE OF THAT PRECIPITATION...WITH SOME LIGHT SNOW SKIMMING THE
AREA MAINLY ON MONDAY. HAVE BACKED OFF MONDAY NIGHT PRECIP MENTION
AS SYSTEM WILL STILL BE WELL WEST AND JUST GETTING ITS ACT
TOGETHER...AND INCREASED TO HIGHER CHANCES ON TUESDAY IN THE
SOUTHERNMOST CWA WHILE TRIMMING POPS IN AREAS NORTH OF I-80 AS DRY
AIR WILL FEED INTO THE NORTHERN CWA AND SUPPRESS NORTHWARD EXPANSION
OF PRECIP.
HIGH PRESSURE WILL DROP INTO THE AREA ON TUESDAY NIGHT AS THE SYSTEM
CLEARS AWAY TO THE SOUTHEAST...AND EXPECT TEMPERATURES WILL BE ABLE
TO FALL QUITE A BIT...ESPECIALLY OVER SNOWY AREAS. HAVE SHAVED A FEW
DEGREES OFF TEMPS ON TUESDAY NIGHT...AND HAVE INCLUDED AN AREA OF
COLDER TEMPERATURES OVER THE SNOWPACK ON WEDNESDAY.
MAYES
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
STILL DRY THROUGH THE PERIOD WITH NO MAJOR WEATHER SYSTEMS OF NOTE
WITH GOOD MODEL AGREEMENT THROUGH FRIDAY. A COLD FRONT DOES MOVE
THROUGH THE REGION ON THURSDAY BRINGING SOME SLIGHTLY COOLER AIR FOR
FRIDAY. MOISTURE IS VERY MEAGER THOUGH...THUS DID NOT ADD ANY
MENTION OF PRECIP AT THIS TIME. MODEL CONTINUITY BEYOND FRIDAY
REMAINS VERY LOW. THE ECMWF BUILDS A RIDGE ACROSS THE CENTRAL US
WITH SUBSTANTIAL WARMING...WHILE THE GFS ALLOWS ANOTHER COLDER SURGE
OF AIR TO MOVE SOUTHWARD SATURDAY AND DOESN/T BEGIN A SLIGHT
WARMUP UNTIL SUNDAY. UNTIL MORE CONTINUITY DEVELOPS...WILL TREND
GRIDS SATURDAY AND SUNDAY TOWARD CLIMATOLOGY/HPC/BLENDED
SOLUTIONS.
DEWALD
&&
.AVIATION...
18Z TAFS FOR KOFK...KOMA AND KLNK.
WESTERN EDGE OF STRATUS AND FOG HAS REMAINED NEARLY STATIONARY
THROUGH THE MORNING WITH LITTLE INDICATION OF MUCH EROSION
FOR THE AFTERNOON. KOFK LIES RIGHT ON THE CLOUD BOUNDARY PER
VISIBLE SATELLITE AND MAY SEE CONDITIONS THERE CHANGE FROM VFR TO
LIFR FOR A TIME THROUGH 00Z. KLNK EXPECTED TO REMAIN IN THE CLEAR
AND KOMA IN LIFR TO IFR CONDITIONS THROUGH 00Z. AFTER 00Z EXPECT
ALL THREE SITES TO DROP TO LIFR CIGS AND VSBY DURING THE EVENING
AND EXTEND INTO MONDAY MORNING.
FOBERT
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS HASTINGS NE
1137 AM CST SUN FEB 5 2012
.AVIATION...18Z TAF. DRY CONDITIONS EXPECTED AT THE TERMINAL FOR
THIS TAF PERIOD...WITH MAIN CONCERN LYING WITH THE POTENTIAL FOR
FOG THIS EVENING/OVERNIGHT. LITTLE/NO CLOUD COVER EXPECTED FOR THE
REST OF THIS AFTERNOON AND INTO THE EVENING...AS THAT AREA OF
LOW LEVEL STRATUS JUST OFF TO THE EAST SHOULD REMAIN THERE. COULD
SEE SOME UPPER LEVEL CLOUDS STARTING TO MOVE IN TOWARD THE END OF
THE PERIOD WITH MODEL TIME HEIGHTS SHOWING INCREASING MOISTURE.
HIGH PRESSURE REMAINS THE PRIMARY FEATURE AT THE SURFACE...WHICH
IS EXPECTED TO BE OVERHEAD BY THIS EVENING...BEFORE STARTING TO
SLIDE TO THE SOUTH. THIS WILL KEEP WINDS IN A GENERALLY WESTERLY
DIRECTION...WITH SPEEDS NEAR/LESS THAN 10 MPH. AM CONCERNED WITH
THE LITTLE CLOUD COVER...LIGHT WINDS...AND POTENTIAL FOR INCREASED
LOW LEVEL MOISTURE FROM SNOW MELT TODAY...THAT SOME FOG WILL
DEVELOP. THOUGH NUMERICAL GUIDANCE ISNT DEPICTING VISIBILITY
ISSUES...SOME OF THE RAW MODEL OUTPUT...NAM/HRRR/RUC...DOES.
DECIDED TO INSERT A HIGH END MVFR VISIBILITY THIS
EVENING/OVERNIGHT...WITH VFR RETURNING TOMORROW MORNING.
&&
PREV DISCUSSION... /ISSUED 235 AM CST SUN FEB 5 2012/
SHORT TERM...TODAY THROUGH TUESDAY NIGHT. 11-3.9 MICRON
SATELLITE IMAGERY EARLY THIS MORNING SHOWED A LARGE AREA OF
STRATUS DROPPING SOUTH FROM EASTERN SOUTH DAKOTA AND MINNESOTA
INTO EASTERN NEBRASKA. THE MODELS OVERALL HAVE NOT DONE A GOOD JOB
IN CAPTURING THIS AREA...THOUGH THE HRRR DOES SEEM TO HAVE AN IDEA
OF ITS PRESENCE. FOLLOWING THE HRRR WOULD SUGGEST THE WESTERN EDGE
OF THE STRATUS COULD MAKE A RUN FOR FAR EASTERN PORTIONS OF THE
FORECAST AREA. WILL INCREASE CLOUDS ACCORDINGLY...BUT IT WILL BE A
SHARPLY DEFINED LINE BETWEEN CLOUDS VS. SUN.
THE NEXT ISSUE WILL BE TEMPERATURES...AND THE MAIN MESSAGE IN THE
FORECAST THE NEXT COUPLE OF DAYS WILL BE TO CUT GUIDANCE
VALUES...ESPECIALLY IN THE HEART OF THE DEEPER SNOWPACK. AM NOT
OVERLY CONFIDENT ABOUT HOW FAR BELOW GUIDANCE TO GO...AND WILL STAY
FAIRLY CLOSE TO THE GOING FORECAST WHICH IS ABOUT 5 TO 10 DEGREES
BELOW BOTH MET AND MAV HIGH TEMPERATURE FORECASTS.
DEBATED ADDING AT LEAST SOME PATCHY FOG TO THE FORECAST TONIGHT WITH
THE 05.00Z NAM SHOWING REDUCED VISIBILITIES OVERNIGHT INTO MONDAY
MORNING. THE MAIN THING THAT KEPT US FROM JUMPING ON IT AT THIS
POINT IS THAT BOUNDARY LAYER RELATIVE HUMIDITY VALUES ARE NOT VERY
HIGH OVERNIGHT...AND PROXIMITY SOUNDINGS ONLY SHOW A VERY SHALLOW
AREA OF NEAR SATURATION. THINK WE MAY SEE SOME VERY SHALLOW GROUND
FOG...BUT WILL LET THE DAY SHIFT TAKE ANOTHER LOOK AT IT BEFORE
ADDING.
THE NEXT CHANCE FOR SNOW COULD ARRIVE MONDAY NIGHT INTO TUESDAY DUE
TO THE ARRIVAL OF THE NEXT MID LEVEL WAVE. CURRENTLY THE SYSTEM IS
SPINNING ACROSS THE INTERMOUNTAIN WEST...AND THE MODELS HAVE COME
INTO GENERAL AGREEMENT THAT IT WILL OPEN UP AND SHIFT ACROSS THE
CENTRAL AND SOUTHERN PLAINS MONDAY INTO TUESDAY. THE FINER DETAILS
REMAIN A BIT DIFFERENT...BUT THE OVERALL MESSAGE FROM THE
DETERMINISTIC MODEL RUNS ALONG WITH THE SREF IS THAT CHANCES OF SNOW
WILL INCREASE MONDAY EVENING IN WESTERN PARTS OF THE FORECAST
AREA...WITH THE CHANCES SPREADING SOUTH AND EAST OVERNIGHT MONDAY
INTO TUESDAY. DISCREPANCIES REMAIN IN THE MODEL GENERATED QPF
FIELDS...BUT BASED ON THE SPEED AND STRENGTH OF THIS SYSTEM IT
APPEARS IT COULD TRY TO GENERATE AN INCH OR SO OF SNOW...PRIMARILY
ACROSS PARTS OF NORTH CENTRAL KANSAS INTO FAR SOUTHERN NEBRASKA.
LONG TERM...WEDNESDAY THROUGH SATURDAY. CONFIDENCE IS REASONABLY
HIGH FOR DRY WEATHER THROUGH THIS 4-DAY PERIOD...ALTHOUGH
CONFIDENCE IN TEMPERATURE TRENDS IS A BIT SHAKY OWING NOT ONLY TO
MODEL DIFFERENCES...BUT ALSO TO UNCERTAINTY IN HOW MUCH IMPACT THE
FRESH SNOW PACK WILL HAVE ON HIGHS. THAT BEING SAID...IT CERTAINLY
LOOKS LIKE AT LEAST SLIGHTLY BELOW-NORMAL TEMPS WILL PERSIST
THROUGH THE PERIOD...AND CURRENT FORECAST MAY NOT BE COLD ENOUGH
AT TIMES...ESPECIALLY OVER THE DEEPER SNOW NEAR/NORTH OF HIGHWAY
6.
STARTING THINGS OUT WEDNESDAY/WEDNESDAY NIGHT...00Z GFS AND ECMWF
RUNS ARE IN REASONABLE AGREEMENT DEPICTING A GENERAL NORTHWEST
FLOW ALOFT OVER THE CENTRAL PLAINS...WITH THE PRIMARY SYNOPTIC LOW
PRESSURE SYSTEMS CONSISTING OF A HUDSON BAY VORTEX WELL TO THE
NORTHEAST...AND A SLOW-MOVING CLOSED LOW OFF BAJA WELL TO THE
SOUTHWEST. MEANWHILE...A LOWER AMPLITUDE MID LEVEL WAVE WILL BE
MOVING AWAY FROM IA EASTWARD. AT THE SURFACE...THERE IS GENERAL
AGREEMENT IN SURFACE HIGH PRESSURE SLIDING EAST DURING THE
DAY...INDUCING SOUTHERLY BREEZES...WHICH THEN TURN MORE WESTERLY
OR POSSIBLY NORTHERLY OVERNIGHT AS THE NEXT COLD FRONT MOVES
IN...BUT THE GFS SOLUTION IS DEFINITELY MUCH MORE AGGRESSIVE WITH
THIS FRONTAL INVASION THAN THE ECMWF. FOR HIGH TEMPS WED...CHANGED
VERY LITTLE FROM PREVIOUS FORECAST...REMAINING A SOLID 3-4 DEGREES
BELOW 00Z MEX GUIDANCE MAINLY TO ACCOUNT FOR SNOW PACK. THIS KEEPS
MOST NEB ZONES ONLY IN THE UPPER 20S...WITH LOW-MID 30S MORE
PREVALENT IN KS ZONES.
THURSDAY/THURSDAY NIGHT...ECMWF/GFS SOLUTIONS AGREE THAT A HIGHLY
AMPLIFIED MID-UPPER RIDGE WILL BUILD OVER THE WESTERN CONUS...BUT
EAST OF THIS FEATURE...THE GFS IS MUCH MORE AGGRESSIVE MOVING A
SHORTWAVE SOUTHWARD THROUGH THE PLAINS...ROTATING AROUND THE MAIN
HUDSON BAY REGION VORTEX. THIS IN TURN MAKES THE GFS MUCH MORE
AGGRESSIVE WITH LOW LEVEL COLD AIR ADVECTION INTO THE CWA. FOR
MOST AREAS KEPT HIGH TEMPS SIMILAR TO BOTH PREVIOUS FORECAST AND
00Z MEX GUIDANCE...WITH LOW 30S OVER DEEPER SNOW AND MID 30S
SOUTH.
FRIDAY/FRIDAY NIGHT...DIFFERENCES WITH SYNOPTIC FEATURES ALOFT
BETWEEN 00Z ECMWF/GFS SOLUTIONS CONTINUE TO MAGNIFY...WITH THE
ECMWF TRYING TO BUILD A SHORTWAVE RIDGE INTO THE CENTRAL PLAINS
MAINLY FRIDAY NIGHT...WHILE THE GFS DROPS AN AMPLIFYING SHORTWAVE
SOUTH THROUGH THE UPPER MS VALLEY/MIDWEST. THIS RESULTS IN A
DRAMATIC DIFFERENCE IN 850MB TEMPS ACROSS THE CWA...AND ALSO WIND
DIRECTION...ESPECIALLY FOR FRIDAY NIGHT WITH THE ECWMF SUGGESTING
OVERNIGHT WARM AIR ADVECTION. THE 00Z GFS ENSEMBLE MEAN 500MB
HEIGHT IS A MIDDLE GROUND BETWEEN THE DETERMINISTIC ECMWF/GFS
SOLUTIONS...AND THUS FOR HIGHS FRIDAY STUCK CLOSE TO MODEL
CONSENSUS WITH MID-UPPER 20S MOST NEB ZONES...AND MID 30S FARTHER
SOUTH. THIS UNDERCUTS 00Z MEX HIGHS BY 2-3 DEGREES MOST AREAS.
FINALLY FOR SATURDAY...CONFIDENCE REALLY GOES IN THE TANK ON THE
SYNOPTIC SCALE PATTERN...WITH THE GFS SHOWING AN EXPANSIVE
COLD SURFACE RIDGE OVER THE PLAINS...WHILE THE ECMWF HAS
IMPRESSIVE WARM ADVECTION AND SOUTHERLY BREEZES AHEAD OF A
SHORTWAVE CROSSING THE CENTRAL ROCKIES. THIS IMPLIES HIGH
TEMPERATURES COULD EASILY RANGE ANYWHERE FROM 20S TO AT LEAST 40S
ACROSS PARTS OF THE CWA...AND FOR NOW WILL PLAY CONSENSUS MIDDLE
GROUND WITH LOW 30S NORTHEAST TO LOW 40S SOUTHWEST. LOTS TO IRON
OUT AT THIS RANGE.
DESPITE THE UPCOMING STRETCH OF BELOW NORMAL TEMPERATURES...EXTENDED
MODELS SHOW NO SIGN OF A LEGITIMATE ARCTIC INVASION. ON ONE FINAL
NOTE...NOW THAT PLENTY OF SNOW IS ON THE GROUND AND LOOKS TO BE
SLOW TO FULLY MELT...THERE COULD EASILY BE POTENTIAL FOR FOG
AND/OR LOW STRATUS DURING THE NEXT WEEK...WITH THE DETAILS JUST
TOO MURKY TO RESOLVE AT THIS TIME.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
AVIATION...ADO
SHORT...KING
LONG...PFANNKUCH
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1251 PM EST SUN FEB 5 2012
.SYNOPSIS...
AN UPPER LEVEL DISTURBANCE WILL PASS THROUGH TODAY...WITH CLOUDS
AND A FEW FLURRIES MAINLY ACROSS CENTRAL NEW YORK. OTHERWISE...DRY
WEATHER WILL CONTINUE INTO THE FIRST PART OF THE WORK WEEK AS HIGH
PRESSURE BUILDS INTO THE REGION FROM THE MIDWEST.
&&
.NEAR TERM /THROUGH TONIGHT/...
1015 AM UPDATE...AS HAS BEEN THE CASE THE LAST FEW DAYS...STRUGGLE
OF THE DAY AGAIN IS STRATOCUMULUS THAT THE MODELS ARE FAILING TO
CAPTURE. MOST UPDATED RUC MODEL...ESPECIALLY RH AROUND
850MB...SEEMS TO HAVE THE BEST HANDLE OF CURRENT SITUATION. SKY
GRIDS WERE INCREASED SIGNIFICANTLY ESPECIALLY FOR THE NEW YORK
ZONES FOR TODAY...AND AS A RESULT...TEMPERATURES WERE ADJUSTED
LOWER. ALSO...COMBINATION OF VORTICITY LOBE SWINGING THROUGH
ALOFT...AND MESOVORTEX THAT DEVELOPED OVER WESTERN LAKE
ONTARIO...WILL ENHANCE THINGS ENOUGH TO PRODUCE A FEW NON-
ACCUMULATING FLURRIES FOR MUCH OF CENTRAL NEW YORK. LATE IN THE
DAY...DIURNAL TIMING...WARM AIR ADVECTION ALOFT...AND BACKING OF
LOW LEVEL FLOW WILL HELP TO BREAK UP THE CLOUDS COVER HEADING INTO
TONIGHT...THOUGH CLOUDS AND A FEW FLURRIES WILL STILL BE POSSIBLE
NORTH OF THE THRUWAY THIS EVENING.
ANOTHER RIPPLE IN THE FLOW COULD SKIM THE AREA WITH BRIEF AXIS OF
MID/HIGH LEVEL CLOUDS OVERNIGHT...BUT OVERALL LOOKING AT LITTLE
CLOUD COVER DURING THE PREDAWN HOURS MONDAY MORNING.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
MORE QUIET WX IN THE SHRT TERM AS NRN STREAM ENERGY STAYS
NORTH...AND DEEP SRN STREAM MOISTURE REMAINS SOUTH. LRG SFC HIPRES
OVER THE MIDDLE OF THE COUNTRY NOSES EAST TO THE MID ATLANTIC
KEEPING THE AREA DRY YET IN A MILD WLY FLOW. ONLY SYSTEM OF NOTE
IN THE PD IS A SHALLOW COLD FNT DROPPING IN FROM THE NORTH TUE.
FNT WILL BRING CLDS AND PERHAPS A FEW FLURRIES...ESP OVER THE
FINGER LAKES AS THE FLOW WITH THE CAA IS MORE NLY THAN NW.
HWVR...AIR IS JUST NOT ALL THAT COLD SO LE WILL BE VERY LIMITED
AND PRBLY CONFINED TO THE AREA OF THE FNT WITH THE ENHANCED LIFT.
TEMPS WILL CONT WELL ABV NRML IN THE PD. MODEL GUID WAS IN GOOD
GNRL AGREEMENT FOR THE PD SO OVERALL CONFIDENCE IN THE FCST IS
HIGH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
UPDATED AS OF 330 PM SAT... OVERALL...NOT A GREAT DEAL OF CHG TO THE
LARGE-SCALE PATTERN SEEN WITH THE MODELS AGAIN TODAY.
EC/GFS/ENSEMBLE CONSENSUS SUGGESTS THAT A VORTEX WILL REMAIN IN
PLACE NEAR HUDSON`S BAY...WITH UPPER-LVL RIDGING OVER WRN CANADA.
ALTHOUGH THIS WILL KEEP FAST MOVG NRN STREAM DISTURBANCES COMING
ACRS NY/PA ABT EVERY 24-36 HRS...IT WILL ALSO KEEP THE GOMEX CUT
OFF. THIS FACTOR...IN COMBINATION WITH A CONTINUED LACK OF SIG HI-
LAT BLOCKING OVER GREENLAND/NWRN ATLANTIC...SHOULD KEEP ANY MAJOR
STORMS/HVY PCPN EVENTS FROM IMPACTING OUR FA THIS PD. ALSO...GIVEN
THE LACK OF SNOW COVER...AND THE LIKELIHOOD THAT THE CORE OF THE
ARCTIC AIR WILL REMAIN N OF THE CANADA/U.S. BORDER...TEMPS SHOULD
CONTINUE TO AVERAGE NEAR TO SOMEWHAT ABV SEASONAL NORMS FOR EARLY FEB.
DAILY WX-WISE...A FAST MOVG UPPER-LVL TROUGH/SFC WAVE ARE EXPECTED
TO UNDERCUT THE ABV MENTIONED ERN CANADIAN VORTEX AND TRACK
THROUGH THE MID-ATL RGN WED...OR PERHAPS EARLY THU. THIS SYSTEM
COULD BRING A SHOT OF LGT SNOW...ALTHOUGH THE NRN EXTENT OF THE
PCPN IS UNCERTAIN ATTM. BOTTOM LN THOUGH...THIS SYSTEM SHOULDN`T
HAVE TIME TO PICK UP MUCH MOIST...SO AGN ANY SNOW LOOKS LIGHT.
OTHERWISE (FROM LATER THU INTO NEXT WEEKEND)...QUICK MOVG IMPULSES
IN THE NRN STREAM WILL REINFORCE POLAR ORIGIN AIR MASSES (HIGHS
MAINLY IN THE 30S...WITH NIGHTTIME LOWS IN THE TEENS AND 20S).
OVERALL...THESE AIR MASSES LOOK INSUFFICIENTLY COLD/MOIST TO
GENERATE MUCH OF A LAKE RESPONSE...SO JUST OCNL FLRYS/-SHSN WILL
BE CALLED FOR IN THE FCST.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
A WEAK TROUGH IS MAKING ITS WAY THROUGH THE FORECAST AREA THIS
AFTERNOON AND WILL CONTINUE TO DO SO THROUGH THE EARLY EVENING
HOURS. THIS WILL KEEP A NORTH TO NORTHWESTERLY FLOW ALOFT AND
CLOUDS IN THE AREA. THE CLOUD DECK IS EXPECTED TO REMAIN ABOVE VFR
FOR THE TAF PERIOD AND SHOULD EVEN BEGIN TO DIMINISH IN THE LATE
EVENING TO EARLY MORNING HOURS.
WINDS RANGE TODAY FROM LIGHT AND VARIABLE UP TO NORTH NORTHWEST
AROUND 10KTS SOUTH OF BGM. MOST LOCATIONS WILL REMAIN LIGHT AND
VARIABLE TONIGHT WITH OTHER LOCATIONS TURNING TO SOUTHWEST AROUND
5 KTS. MONDAY MORNING WILL SEE WINDS OUT OF THE WEST SOUTHWEST
AROUND 10KTS.
.OUTLOOK...
MON NGT-TUE NGT...VFR WITH PSBL MVFR IN LAKE-EFFECT SHSN.
WED...MAINLY VFR...BUT MVFR POSSIBLE TOWARD EVENING IN LGT SNOW.
THU AND FRIDAY...VFR/MVFR PSBL IN LGT SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...MDP
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...MLJ
AVIATION...SLI
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
300 PM CST SUN FEB 5 2012
.DISCUSSION.../ISSUED AT 300 PM CST/
AGAIN STRATUS WITH SOME LIGHT FOG HAD BEEN STUBBORN ABOUT ERODING.
TODAY THE PROBLEM AREA IS EASIER TO DIAGNOSE DOWN IN NORTHWEST IOWA
AWAY FROM THE BEST MIXING AND CLOSEST TO THE SNOW COVER. SHORT TERM
MODELS KEEP THIS IN AND THIS LOOKS REASONABLE WITH THE FINE DETAILS
BEING THE TRICKY PART. WILL KEEP IN ALL NIGHT THIS AREA ALONG WITH
SOME AREAS OF FOG...AND EXPAND THE FOG MENTION BEYOND THE STRATUS
LATE TONIGHT IN THE EAST. AT THIS TIME AM NOT ANTICIPATING DENSE
FOG. THERE IS SOME QUESTION ABOUT REDEVELOPMENT FURTHER NORTHWEST
TOWARD DE SMET WHERE THE LAST OF THE STRATUS NORTH OF I90 IS
STUBBORNLY SHRINKING. WILL KEEP THE REDEVELOPMENT OUT FOR NOW.
ANOTHER AREA MIGHT BE SOUTHERN PART OF SOUTHWEST MN WHICH HAS ALSO
BEEN THE LATEST TO LOSE THE LOW CLOUDS...AND WHERE THE HRRR TRIES TO
BRING IT BACK IN SOME. WESTERN AREAS SHOULD STAY PRETTY CLEAR. LOW
TEMPERATURES SHOULD BE INT HE 20S. LIGHT WEST TO SOUTH WINDS SHOULD
RULE WEST AND NORTH...WITH LIGHT TO CALM SURFACE WINDS SOUTHEAST.
/ WILLIAMS
LINGERING STRATUS/FOG IN THE SOUTHEAST SHOULD CLEAR BY MID-LATE
MORNING AS LIGHT WINDS BECOME WESTERLY AHEAD OF THE COLD FRONT.
FRONTAL TIMING SIMILAR TO EARLIER SHIFT...ENTERING NORTHERN CWA LATE
MORNING...AND EXITING THE SOUTHEAST JUST AFTER SUNSET. SHOULD SEE
DECENT MIXING AHEAD OF AND IMMEDIATELY BEHIND THE FRONT...HELPING
MOST AREAS CLIMB INTO THE 40S WITH WARMEST READINGS ALONG AND SOUTH
OF I-90.
CLOUDS INCREASE BEHIND THE FRONT MONDAY NIGHT...WITH BAND OF STRATUS
POSSIBLE BEHIND THE FRONT DROPPING IN FROM THE NORTH...AND MID CLOUD
DECK EXPANDING ACROSS THE AREA FROM THE SOUTHWEST. THESE TWO LAYERS
OF MOISTURE NEVER REALLY SEEM TO CO-EXIST IN ANY ONE AREA UNTIL LATE
MONDAY NIGHT/EARLY TUESDAY OVER FAR SOUTHERN PARTS OF THE CWA...AND
WILL LIMIT MENTION OF A FEW FLURRIES TO THESE AREAS 06Z-18Z. NAM IS
PRODUCING SOME LIGHT QPF FARTHER NORTH MONDAY NIGHT...BUT SOUNDINGS
WOULD ONLY SUPPORT FREEZING DRIZZLE WITH TEMPERATURES IN THE CLOUD
LAYER NOT COLD ENOUGH TO INTRODUCE ICE INTO THE LAYER. NOT EVEN
HIGHLY CONFIDENT THAT THE BAND OF HIGHER RH INDICATED BY THE MODELS
WILL BE A BONAFIDE STRATUS BAND AND IS NOT JUST AN ARTIFACT OF THE
STRONG COLD ADVECTION...SO WILL LEAVE FORECAST DRY NORTH OF HIGHWAY
18.
LIMITED DIURNAL RANGE MONDAY NIGHT/TUESDAY WITH THE COLD ADVECTION
AND 925MB TEMPS FROM -8C TO -13C TUESDAY AFTERNOON...BUT COLD SNAP
WILL BE SHORT-LIVED AS WITH WEST-SOUTHWEST FLOW AND MOSTLY SUNNY
SKIES AIDING MIXING ON WEDNESDAY...SO WILL STICK WITH TEMPERATURES
MIXED A LITTLE HIGHER THAN 925MB...YIELDING HIGHS IN THE LOWER TO
MID 30S.
ARCTIC COLD FRONT PUSHES THROUGH THE REGION THURSDAY AS POLAR VORTEX
SETS UP CAMP OVER HUDSON BAY...AND MODELS STILL HAVING A TOUGH TIME
AGREEING ON WESTWARD EXTENT AND DURATION OF THE COLDEST AIR INTO THE
NORTHERN PLAINS. 00Z DETERMINISTIC RUNS FEATURED GFS ON COLD END OF
THE SPECTRUM /850MB TEMPS FRIDAY AFTN -16C TO -23C WEST TO EAST/...
WHILE ECMWF WAS QUITE A BIT WARMER /-3C TO -8C FOR SAME TIME FRAME/.
DIFFERENCES PERSISTED INTO SATURDAY...WHEN AFTERNOON 850MB TEMPS
RANGED FROM -10C TO -18C ON THE GFS...TO +10C TO +6C WEST TO EAST ON
THE ECMWF. 12Z DETERMINISTIC RUNS ESSENTIALLY FLIP-FLOPPED...THOUGH
WITH GENERAL TREND TOWARD THE MIDDLE WITH GFS TRENDING WARMER AND
ECMWF TRENDING COLDER THAN THEIR RESPECTIVE PREVIOUS RUNS. ALL THIS
LEADS TO VERY LOW CONFIDENCE IN TEMPERATURE FORECAST FOR THURSDAY
NIGHT THROUGH SATURDAY NIGHT AND WILL STICK FAIRLY CLOSE TO MIDDLE
GROUND WITH MODEL CONSENSUS FOR NOW. WHAT IS A LITTLE MORE CLEAR IS
THAT FRIDAY SHOULD BE THE COLDEST DAY OF THE LONG RANGE PERIOD...
WITH SUBTLE WARMUP FOR SATURDAY...AND GREATER WARMUP MORE LIKELY FOR
NEXT SUNDAY. ALSO FAIRLY CONFIDENT IN CONTINUED DRY FORECAST AS
MOISTURE QUITE LIMITED THROUGHOUT THE LATE WEEK/WEEKEND PERIOD OVER
OUR AREA.
&&
.AVIATION.../FOR THE 18Z TAF ISSUANCE/UPDATED
STRATUS AND SOME FOG WILL CONTINUE OVER NORTHWEST IOWA INCLUDING
SUX. IN THIS AREA IFR CEILINGS AND AREAS OF LIGHT FOG WILL LIKELY
LOWER AGAIN TO LIFR CEILINGS AND VSBYS BELOW 3SM DURING THE NIGHT.
TO THE NORTH...SOME AREAS OF FOG MAINLY 3-5SM POSSIBLE EAST OF THE
JAMES RIVER AFTER 06/06Z. VFR WEST OF THE JAMES RIVER. AFTER 06/14Z
CONDITIONS SHOULD IMPROVE TO VFR EVEN IN NORTHWEST IA DUE TO
INCREASING MIXING AHEAD OF APPROACHING COLD FRONT.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
351 PM CST SUN FEB 5 2012
.SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...A SMALL AREA OF LIGHT
RAIN MOVING THROUGH THE CENTRAL COASTAL BEND WILL MOVE OFFSHORE
OVER THE NEXT FEW HOURS. BEYOND THAT THINK PRECIPITATION THREAT IS
MAINLY OVER FOR THE EVENING. HRRR AND RUC MODELS INDICATE A
CHANCE FOR LIGHT RAIN ALONG THE SOUTHERN BORDER OF THE FORECAST
AREA AND UP TOWARD CORPUS THROUGH THE EVENING...HOWEVER THEY BOTH
SHOW PRECIP TO THE SOUTH AND WEST AT THIS TIME THAT IS NOT BEING
REALIZED...SO THINK THEY ARE PROBABLY OVERDOING THE CHANCE
TONIGHT. WILL STILL LEAVE CHANCE WORDING EAST AND SLIGHT CHANCE
CENTRAL THROUGH THE NIGHT. WITH THE RAINFALL AMOUNTS EXPERIENCED
OVERNIGHT LAST NIGHT...AND WATER STILL STANDING IN SOME
AREAS...HAVE TO CONSIDER THE CHANCE FOR SOME PATCHY FOG TONIGHT.
SKIES TO REMAIN CLOUDY...AND WINDS IN THE EAST SHOULD STAY HIGH
ENOUGH TO LIMIT THE POSSIBILITY. HAVE NOT INCLUDED IN THE FORECAST
AT THIS TIME...BUT CAN NOT RULE IT OUT COMPLETELY.
SHOULD COOL TEMPS MORE TONIGHT WITH LOWS IN THE 40S FOR MOST OF
THE AREA. MOSTLY CLOUDY SKIES CONTINUE TOMORROW AND WILL LIMIT
WARMING. HAVE COOLED HIGH TEMPS A BIT AS MODELS SEEM TO ALL BE
COMING IN WITH COOLER SOLNS TODAY. MOISTURE BEGINS TO COME BACK
INTO THE AREA MONDAY NIGHT...BUT LOOKS LIKE PRECIP
CHANCES...EXCEPT OFFSHORE...WILL HOLD OFF UNTIL TUESDAY.
&&
.LONG TERM (TUESDAY THROUGH SUNDAY)...WEAK ISENTROPIC LIFT WILL
DEVELOP ACROSS THE COASTAL BEND TUESDAY AFTERNOON AS A MID LVL S/W
AND UPR JET STREAM MOVES OVHD...RESULTING IN A SLIGHT CHANCE OF
LIGHT PCPN. SFC RIDGE WILL BE REINFORCED OVER THE GULF WATERS
WEDNESDAY MORNING AS PROGRESSIVE TROUGH ADVANCES ACROSS THE OHIO
VALLEY. INCREASING UPR DIFLUENCE AND OMEGA WITH THE ADVANCEMENT OF
THE NEXT DEEP TROUGH DIGGING INTO BAHA WILL PRODUCE A CONTINUATION
OF LIGHT RAIN ON WEDNESDAY. 115KTS UPR JET WILL NOSE INTO SOUTH
TEXAS LATE WED NIGHT/THU AND WILL COMBINE WITH ELEVATED INSTABILITY
TO PRODUCE A GOOD CHANCE OF SHOWERS AND THUNDERSTORMS THURSDAY...
CONTINUING THROUGH SATURDAY MORNING WHEN THE UPR LVL TROUGH AXIS
SHIFTS EAST OF THE AREA. PRECIP AMOUNTS WILL HINGE ON AMOUNT OF
MOISTURE TRANSPORT AHEAD OF THE SYSTEM...WHICH LOOKS WEAKER THAN THE
LAST SYSTEM (PWATS NEAR 1" -VS- 1.5" LAST NIGHT). NONE THE
LESS...EXPECT POTENTIAL FOR RAINFALL AND ABNORMALLY WET LA NINA
FEBRUARY TO CONTINUE MUCH OF THE WEEK. CONSIDERABLE UNCERTAINTY
WITH REGARDS TO NEXT WEEKEND AS THE GFS IS DRY IN THE WAKE OF THE
EXITING LARGE SCALE TROUGH AND THE ECMWF IS MORE PROGRESSIVE IN
BRINGING ANOTHER SOUTHERN STREAM TROUGH ACROSS THE AREA. FOR
NOW...WILL HEDGE TOWARD THE DRIER FORECAST. TEMPS WILL REMAIN BELOW
NORMAL THROUGH THE FORECAST PERIOD. SCA`S WILL DEVELOP OVER THE
GULF WATERS WED AND WILL PERSIST INTO THE WEEKEND AS SFC HIGH
PRESSURE REMAINS ANCHORED ALONG THE COAST AND THE AFORMENTIONED
STORM SYSTEM MOVES ACROSS THE REGION.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 45 58 45 65 50 / 40 10 10 20 30
VICTORIA 42 58 42 64 46 / 30 10 10 20 20
LAREDO 46 63 48 66 52 / 10 10 10 10 30
ALICE 43 60 43 65 49 / 30 10 10 20 30
ROCKPORT 46 59 51 66 50 / 40 10 10 20 30
COTULLA 43 60 42 64 48 / 10 10 10 10 20
KINGSVILLE 43 60 44 66 50 / 40 10 10 20 30
NAVY CORPUS 48 60 48 67 50 / 40 10 10 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
&&
$$
PZ/83...SHORT TERM
JM/75...LONG TERM
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
1158 AM CST SUN FEB 5 2012
.DISCUSSION...UPDATED FOR 18Z AVIATION.
&&
.AVIATION...ANOTHER AREA OF LIGHT TO MODERATE RAIN IS LOCATED
BETWEEN LRD AND ALI AT THIS TIME. THIS AREA OF RAIN IS MOVING
EASTWARD AND WILL AFFECT THE TAF SITES OVER THE NEXT SEVERAL
HOURS. THE ACTIVITY IS ELEVATED AND CIGS SHOULD REMAIN GENERALLY
VFR...BUT MAY BECOME MVFR DURING A HEAVIER SHOWER. WINDS REMAIN
BREEZY OUT OF THE NORTH. OVERNIGHT CHANCES FOR RAIN DECREASE...BUT
CANT RULE OUT SOME LINGERING LIGHT RAIN...MAINLY IN THE SOUTHEAST.
SKIES REMAIN OVC TOMORROW WITH CIGS BORDERLINE MVFR.
&&
.PREV DISCUSSION... /ISSUED 957 AM CST SUN FEB 5 2012/
DISCUSSION...WIDESPREAD MODERATE RAIN FROM THIS MORNING HAS
PUSHED OFFSHORE. HOWEVER...ADDITIONAL LIGHT RAIN WITH EMBEDDED
MODERATE SHOWERS IS DEVELOPING UNDER THE RIGHT REAR QUAD OF AN
UPPER JET REMAINING OVER MEXICO AND WEST CENTRAL TEXAS. THE JET
WEAKENS AND SHIFTS TO THE EAST LATER TODAY WHICH SHOULD DECREASE
PRECIP CHANCES. ALTHOUGH LATEST GFS JUST COMING IN AS I TYPE THIS
SHOWS A BIT OF A JET STREAK OVER FAR EASTERN CWA OVERNIGHT...WHICH
COINCIDES WITH PRECIP INDICATED ON SOME MESO MODELS. WILL ANALYZE
MORE FOR AFTERNOON FORECAST PACKAGE. HAVE ALSO SEEN WINDS
BECOMING VERY GUSTY ALONG THE COASTAL BEND LATE THIS MORNING WITH
POSSIBLY A WEAK WAKE LOW DEVELOPING. MSAS 3HR PRESSURE CHANGE DID
INDICATE A BIT OF A MINIMUM NEAR BAFIN BAY THEN NORTHWARD TO
MATAGORDA BAY. MARGINAL WIND ADVISORY NOW IN EFFECT THROUGH NOON
FOR COASTAL COUNTIES. HAVE SEEK SEVERAL GUSTS IN THE 30 TO 40 MPH
RANGE WITH A GUST TO 46 MPH AT KNGP.
PREV DISCUSSION... /ISSUED 545 AM CST SUN FEB 5 2012/
DISCUSSION...SEE AVIATION SECTION FOR 12Z TAFS.
AVIATION...LARGE SHIELD OF PRECIPITATION WILL MOVE NORTHEAST
ACROSS SOUTH TEXAS THIS MORNING WITH A GRADUAL DECREASE FROM
WEST TO EAST AS THE UPPER LEVEL DISTURBANCE OVER NORTHERN
MEXICO MOVES NORTHEAST INTO CENTRAL TEXAS. MVFR CEILINGS/VSBYS
WILL BE PREVALENT THIS MORNING WITH PERIODIC IFR VSBYS IN THE
HEAVIER DOWNPOURS ASSOCIATED WITH EMBEDDED THUNDERSTORMS.
OVERCAST CONDITIONS WILL EXIST AS THE PRECIPITATION ACTIVITY
DIMINISHES LATE THIS AFTERNOON WITH CEILINGS RISING TO NEAR
5 KFT BRUSH COUNTRY...3500 FT FOR INLAND COASTAL PLAINS AND
CEILINGS REMAINING AROUND 3 KFT ALONG THE COAST THROUGH THE
NIGHT.
PREV DISCUSSION... /ISSUED 355 AM CST SUN FEB 5 2012/
SHORT TERM (TODAY)...LARGE SCALE ATMOSPHERIC LIFT INCREASED
LAST EVENING IN RESPONSE TO AN UPPER LEVEL JET STREAK THAT LIFTED
TO THE NORTH OF THE AREA. WIDESPREAD SHOWERS/SCATTERED THUNDERSTORMS
CONTINUE EARLY THIS MORNING WITH MORE TO COME. LARGE AREA OF
CONVECTION MOVING NORTHEAST FROM DEEP SOUTH TEXAS THIS MORNING.
WATER VAPOR IMAGERY SHOWS ANOTHER ENERGETIC UPPER LEVEL JET STREAK
LIFTING NORTH-NORTHEAST OUT OF MEXICO. LATEST RUC SHOWS A 90 KNOT
25H JET MOVING INTO COAHUILA THAT WILL MOVE INTO CENTRAL TEXAS
THIS AFTERNOON. SOUTH TEXAS WILL AGAIN BE IN A REGION OF INCREASING
LIFT IN RESPONSE TO INCREASING UPPER LEVEL DIVERGENCE. FORECAST
SOUNDINGS CONTINUE TO SHOW ELEVATED UNSTABLE LAYER ABOVE 800 MBS
REMAINING OVER THE REGION THROUGH THE DAY. GFS/ECMWF/NAM SHOW THE
85H TROUGH AXIS OVER THE BRUSH COUNTRY WITH THE GOOD MOISTURE FLUX
CONVERGENCE MOVING FROM THE BRUSH COUNTRY THROUGH THE COASTAL BEND
THROUGH THE DAY. TIME-HEIGHT CROSS SECTIONS SHOW LIFT THROUGH A
LARGE LAYER THROUGH THE MORNING INTO MID AFTERNOON. WILL GO WITH
CATEGORICAL POPS FOR MOST OF THE AREA EXCEPT WESTERN BRUSH COUNTRY
WHERE WENT WITH LIKELY POPS. QPF FORECAST WAS A BLEND OF THE
CMC/ECMWF/SREF WITH AVERAGE OF A LITTLE OVER HALF OF AN INCH ALONG
THE COAST...BUT THERE WILL BE AREAS THAT COULD RECEIVE UP TO AN
INCH. PRECIPITABLE WATER VALUES WILL BE ABOVE 1 INCH BRUSH COUNTRY
AND BE NEAR 1.5 INCHES OVER THE GULF WATERS.
MARINE (TODAY THROUGH TONIGHT)...HIGH PRESSURE BUILDING INTO THE
AREA WILL KEEP WINDS A BIT STRONGER AND REMAIN IN SCA RANGE FOR
A LITTLE LONGER. EXTENDED SCA FOR THE BAYS UNTIL 20Z AND FOR THE
GULF WATERS UNTIL 03Z MONDAY. WIDESPREAD SHOWERS AND THUNDERSTORMS
WILL CONTINUE THROUGH THE DAY WITH A DECREASE IN COVERAGE THIS
EVENING.
LONG TERM (TONIGHT THROUGH SATURDAY)...PRECIP EXPECTED TO DIMINISH
TONIGHT AS UPPER DISTURBANCE EXITS THE AREA. THE CANADIAN AND NAM
KEEP LIGHT PRECIP IN THE FCST ON MON...HOWEVER LEANED TOWARD THE
DRIER ECMWF AND GFS. MODELS CONTINUE TO PROG A SERIES OF EMBEDDED
SHORT WAVES TO TRACK ACROSS THE REGION THROUGH THE WEEK AHD OF A
POTENT CUT OFF LOW. MODELS DIFFER ON QPF EACH DAY AND THEY DIFFER ON
LOCATION OF HEAVIEST PRECIP. KEPT WITH THE CHC POPS DVLPG ACROSS THE
SRN CWA BY TUE NITE AND SHIFTING INTO THE WESTERN HALF OF THE CWA
THRU WED. THEN AS THE UPPER LOW MOVES ACROSS MEX TOWARD TX...UPPER
DIFFLUENCE INCREASES. THE HIGHEST PWATS ARE PROGD FOR THU AND LOW
LEVEL MOISTURE CONVERGENCE INCREASES AS A COLD FRONT/REINFORCING
HIGH PRESSURE PUSHES S INTO THE AREA. THEREFORE KEPT THE 50 POPS
ACROSS THE WEST DUE TO PROXIMITY TO UPPER LOW/BEST DYNAMICS. KEPT A
BROADBRUSHED 30 POP FOR FRI AS MODELS BEGIN TO DIVERGE ON
PLACEMENT/STRENGTH OF UPPER LOW AND CORRESPONDING PRECIP. GFS SHOWS
A DRIER FCST BY SAT AFTERNOON AS THE UPPER SYSTEM PUSHES THRU THE
AREA AND A NW FLOW ALOFT DVLPS. THE ECMWF IS A TAD SLOWER. WENT WITH
A BROADBRUSHED 20 POP ON SAT FOR NOW. AS FOR TEMPS...WENT WITH A
WARMING TREND MON THRU THU AHD OF COLD FRONT...THEN A SLIGHT COOLING
TREND FRI AND SAT IN THE WAKE OF THE COLD FRONT. OVERALL TEMPS ARE
PROGD TO BE GENERALLY BELOW NORMAL THROUGH THE WEEK.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 50 44 60 45 65 / 80 40 10 10 20
VICTORIA 50 41 58 42 64 / 80 20 10 10 20
LAREDO 54 46 61 46 66 / 60 10 10 10 10
ALICE 51 43 59 42 65 / 80 30 10 10 20
ROCKPORT 51 46 60 49 66 / 80 40 10 10 20
COTULLA 52 41 59 42 64 / 70 10 10 10 10
KINGSVILLE 50 43 59 44 66 / 80 40 10 10 20
NAVY CORPUS 52 46 60 48 67 / 80 40 10 10 20
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 9 PM CST THIS EVENING FOR THE
FOLLOWING ZONES: COASTAL WATERS FROM BAFFIN BAY TO PORT
ARANSAS OUT 20 NM...COASTAL WATERS FROM PORT ARANSAS TO
MATAGORDA SHIP CHANNEL OUT 20 NM...WATERS FROM BAFFIN BAY
TO PORT ARANSAS FROM 20 TO 60 NM...WATERS FROM PORT ARANSAS
TO MATAGORDA SHIP CHANNEL FROM 20 TO 60 NM.
SMALL CRAFT ADVISORY UNTIL 2 PM CST THIS AFTERNOON FOR THE
FOLLOWING ZONES: BAYS AND WATERWAYS FROM BAFFIN BAY TO PORT
ARANSAS...BAYS AND WATERWAYS FROM PORT ARANSAS TO PORT
O`CONNOR.
&&
$$
PZ/83...SHORT TERM
TE/81...LONG TERM
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
341 PM CST SUN FEB 5 2012
.SHORT TERM...TONIGHT THROUGH WEDNESDAY
340 PM CST SUN FEB 5 2012
AT 3 PM...A 1033 MB HIGH WAS LOCATED ACROSS NEBRASKA AND KANSAS. A
SUBSIDENCE INVERSION ASSOCIATED WITH THIS HIGH REMAINS ACROSS THE
UPPER MISSISSIPPI RIVER VALLEY. MOISTURE TRAPPED BENEATH THIS
INVERSION HAS KEPT SKIES GENERALLY CLOUDY AND THIS HAS PREVENTED
THE TEMPERATURES FROM RISING OUT OF THE LOWER 30S. THE ONLY
EXCEPTION IS NORTH CENTRAL AND CENTRAL WISCONSIN WHERE THERE HAS
BEEN SUNSHINE MUCH OF THE AFTERNOON...AND THIS ALLOWED
TEMPERATURES TO CLIMB INTO THE MID AND UPPER 30S IN THESE AREAS.
WITH LOW CLOUDS SPREADING EAST...THESE AREAS WILL LIKELY HAVE TO
CONTEND WITH SOME CLOUDS FOR AT LEAST THIS EVENING.
THE MAIN FORECAST QUESTION TONIGHT AND EARLY MONDAY IS WHETHER THE
CLEARING LOCATED WILL MAKE IT INTO THE AREA. HRRR AND RUC SUGGEST
THAT THIS CLEARING WILL NOT MAKE IT INTO MUCH OF THE AREA /ONE
EXCEPTION IS NORTH CENTRAL WISCONSIN/ TONIGHT...AND WE WILL HAVE
TO WAIT UNTIL MONDAY MORNING WHEN THE WESTERLY DOWN SLOPE WIND MOVES
INTO THE AREA AHEAD OF THE FRONT. HOWEVER THERE IS ALSO A POSSIBILITY
THAT THIS AIR MASS MAY BE ISENTOPICALLY LIFTED UP AND OVER THE LOW
LEVEL MOISTURE AND THE AREA WILL REMAIN IN CLOUDS. WITH QUITE A
BIT OF CLEARING TAKING PLACE ACROSS THE DAKOTAS... DECIDED TO GO
MORE OPTIMISTIC. IF WE ARE ABLE TO GET SOME SUNSHINE...TEMPERATURES
WILL CLIMB INTO THE MID AND UPPER 40S. HOWEVER IF THE CLOUDS FAIL
TO BREAK UP...TEMPERATURES WILL REMAIN IN THE 30S. SINCE THERE IS
SOME UNCERTAINTY...DECIDED TO TAKE A BIT OF CONSERVATIVE APPROACH
AND JUST GO WITH TEMPERATURES IN THE LOWER AND MID 40S.
UNLIKE YESTERDAY...THE MODELS HAVE ONCE AGAIN HAVE SPEED UP THE
CANADIAN COLD FRONT. IT NOW LOOKS LIKE THE FRONT WILL MOVE THROUGH
THE AREAS NORTH OF THE INTERSTATE 90 CORRIDOR LATE MONDAY
AFTERNOON AND THROUGH THE REMAINDER OF THE AREA DURING THE
EVENING. THE COLD AIR IS LAGGING THIS FRONT BY ABOUT 9 TO
12 HOURS...SO NOT EXPECTING THE LOWS ON MONDAY NIGHT TO BE
SIGNIFICANTLY COLDER THAN THEY ARE TONIGHT. IN THE WAKE OF THIS
FRONT...IT CONTINUES TO LOOK LIKE THERE WILL BE CLOUDS AND
FLURRIES. THE NAM/WRF CONTINUES TO HAVE DEEPER MOISTURE THAN THE
GFS...BUT THERE IS NOT ENOUGH OF A DIFFERENCE TO PRECLUDE FLURRIES
FROM OCCURRING ON MONDAY NIGHT AND TUESDAY.
IN ADDITION OVER THE PAST COUPLE OF DAYS...IT LOOKED LIKE SKIES
WOULD CLEAR OUT QUICKLY BEHIND THE FRONT...BUT A CAREFUL
EXAMINATION OF SOUNDINGS AND THE LAYER BELOW 875 MB LOOKS LIKE A
DECK OF STRATUS WILL LINGER ACROSS THE AREA THROUGH TUESDAY...AND
THEN MODELS DIFFER WITH THE GFS CLEARING MUCH OF THE AREA OUT ON
TUESDAY NIGHT AND THE NAM/WRF KEEPING THE AREA CLOUDY THROUGH
WEDNESDAY. ACTUALLY PREFER THE LATTER SOLUTION. HOWEVER WITH SUCH
A DIFFERENCE IN THE MODELS...DECIDED TO JUST GO WITH A BLEND OF
THEM.
.LONG TERM...WEDNESDAY NIGHT THROUGH SUNDAY
340 PM CST SUN FEB 5 2012
ON THURSDAY...THE 05.12Z MODELS CONTINUE TO SUGGEST THAT SOME
WARMING WILL TAKE PLACE AHEAD OF THE NEXT CANADIAN COLD FRONT. THE
ECMWF ACTUALLY WARMS TEMPERATURES IN THE UPPER 30S. MEANWHILE THE
GEM KEEPS TEMPERATURES MAINLY IN THE MID AND UPPER 20S. SINCE
THERE WAS SUCH A DIFFERENCE AND THE ECMWF USUALLY DOES BETTER FOR
THIS TIME PERIOD...DECIDED TO GO WITH A BLEND OF THESE TWO.
ON FRIDAY...IT CONTINUE TO LOOK LIKE THE COLDEST AIR WILL BE
LOCATED ACROSS THE AREA. HOWEVER WITH THIS SAID...IT IS STILL A
MUCH WARMER SOLUTION THAN WHAT IT LOOKED LIKE 3 DAYS AGO. HIGH
TEMPERATURES ON THIS DAY WILL LIKELY RANGE FROM THE TEENS TO MID
20S WHICH IS ONLY 5 TO 10 DEGREES BELOW NORMAL.
LIKE THE PAST COUPLE OF DAYS...IT LOOKS LIKE THE LONG WAVE TROUGH
WILL MOVE QUICKLY OUT OF THE AREA DURING NEXT WEEKEND...AND THE
AREA WILL ONCE AGAIN SEE A RETURN TO ABOVE-NORMAL TEMPERATURES.
THE ECMWF IS BY FAR THE MOST AGGRESSIVE WITH ITS HIGH TEMPERATURES
IN THE MID AND UPPER 40S BY SUNDAY.
&&
.AVIATION...THROUGH 18Z MONDAY
1156 AM CST SUN FEB 5 2012
FORECAST AGAIN DEALS WITH STRATUS. AS OF 18Z SUNDAY...STRATUS
EXISTS ACROSS ABOUT THE SOUTHERN 2/3 OF MINNESOTA AND MOST OF
IOWA...INCLUDING ADJACENT AREAS OF WISCONSIN. CEILINGS RANGE FROM
LIFR TO IFR WITH VISIBILITIES NOW MOSTLY MVFR. DAYTIME MIXING AND
A GRADUAL INCREASING WEST WIND WILL LIKELY ERODE SOME OF THE
STRATUS THROUGH TONIGHT...ESPECIALLY ALONG AND NORTH OF I-94.
FOR THE TAF SITES...THE INCREASING WEST WIND REALLY DOES NOT OCCUR
UNTIL TONIGHT. WITHOUT THE DAYTIME MIXING HELPING OUT...THE
INCREASING WEST WIND MAY NOT BE ENOUGH TO ERODE THE STRATUS. THIS
IS IN AGREEMENT WITH MODEL FORECASTS TOO. THEREFORE...HAVE WENT
MUCH MORE PESSIMISTIC WITH THE AVIATION FORECAST. LOOKS LIKE
AROUND 15-16Z MONDAY...THE CLOUDS SHOULD SCATTER OUT AT THE TAF
SITES DUE TO A COMBINATION OF THE DAYTIME MIXING...THE WESTERLY
WINDS AND AN APPROACHING COLD FRONT FROM THE NORTH. LOOKING
AHEAD...ADDITIONAL LOW STRATUS APPEARS POSSIBLE ONCE THE COLD FRONT
PASSES LATE MONDAY.
IF THE STRATUS OVER SOUTHWEST AND SOUTH CENTRAL MINNESOTA CAN
DISSIPATE MORE THAN EXPECTED...THEN CLEARING WOULD COME INTO
THE TAF SITES EARLIER...PROBABLY MORE 03-04Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
340 PM CST SUN FEB 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
STRATUS WILL BE INCLUDED IN THE NEXT AREA FORECAST DISCUSSION
LATER THIS AFTERNOON.
.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY
249 AM CST SUN FEB 5 2012
FOCUS IN THE EXTENDED CONTINUES TO BE WITH A COLD FRONT THAT IS
PROGGED TO COME THROUGH LATER IN THE WEEK. THE 05.00Z GFS
CONTINUES ITS TREND OF BEING THE FASTEST WITH THIS FEATURE AND
BRINGS IT THROUGH EARLY ON THURSDAY WHILE THE 05.00Z ECMWF IS
STILL SLOWER AND DOES NOT DROP THE FRONT THROUGH UNTIL FRIDAY.
INTRODUCED SOME LIGHT SNOW CHANCES ACROSS NORTH CENTRAL WISCONSIN
WITH THIS FEATURE AS THE GFS HAS BEEN SHOWING SOME POSSIBLE QPF UP
THERE THE PAST FEW RUNS.
OTHERWISE DIFFERENCES CROP UP GOING INTO THE WEEKEND WITH HOW LONG
THE COLD LOW LEVEL AIR REMAINS IN PLACE WITH THE 05.00Z GFS NOW
HOLDING ONTO 850MB TEMPERATURES BELOW -20C INTO THE WEEKEND WHILE
THE 05.00Z ECMWF PUSHING THE COLD AIR RAPIDLY OFF TO THE EAST LOW
LEVEL WARM AIR ADVECTION KICKING IN BY SATURDAY. GIVEN THESE
DISCREPANCIES...CONFIDENCE IS NOT ALL THAT HIGH IN HOW
TEMPERATURES WILL END UP TOWARD THE LATER PORTION OF THE FORECAST
PACKAGE.
&&
.AVIATION...THROUGH 18Z MONDAY
1156 AM CST SUN FEB 5 2012
FORECAST AGAIN DEALS WITH STRATUS. AS OF 18Z SUNDAY...STRATUS
EXISTS ACROSS ABOUT THE SOUTHERN 2/3 OF MINNESOTA AND MOST OF
IOWA...INCLUDING ADJACENT AREAS OF WISCONSIN. CEILINGS RANGE FROM
LIFR TO IFR WITH VISIBILITIES NOW MOSTLY MVFR. DAYTIME MIXING AND
A GRADUAL INCREASING WEST WIND WILL LIKELY ERODE SOME OF THE
STRATUS THROUGH TONIGHT...ESPECIALLY ALONG AND NORTH OF I-94.
FOR THE TAF SITES...THE INCREASING WEST WIND REALLY DOES NOT OCCUR
UNTIL TONIGHT. WITHOUT THE DAYTIME MIXING HELPING OUT...THE
INCREASING WEST WIND MAY NOT BE ENOUGH TO ERODE THE STRATUS. THIS
IS IN AGREEMENT WITH MODEL FORECASTS TOO. THEREFORE...HAVE WENT
MUCH MORE PESSIMISTIC WITH THE AVIATION FORECAST. LOOKS LIKE
AROUND 15-16Z MONDAY...THE CLOUDS SHOULD SCATTER OUT AT THE TAF
SITES DUE TO A COMBINATION OF THE DAYTIME MIXING...THE WESTERLY
WINDS AND AN APPROACHING COLD FRONT FROM THE NORTH. LOOKING
AHEAD...ADDITIONAL LOW STRATUS APPEARS POSSIBLE ONCE THE COLD FRONT
PASSES LATE MONDAY.
IF THE STRATUS OVER SOUTHWEST AND SOUTH CENTRAL MINNESOTA CAN
DISSIPATE MORE THAN EXPECTED...THEN CLEARING WOULD COME INTO
THE TAF SITES EARLIER...PROBABLY MORE 03-04Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
249 AM CST SUN FEB 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...AJ
LONG TERM....HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1156 AM CST SUN FEB 5 2012
.SHORT TERM...TODAY THROUGH WEDNESDAY
249 AM CST SUN FEB 5 2012
ANOTHER DAY OF TRYING TO FORECAST STRATUS AND TEMPERATURES IS ON
DECK FOR TODAY FOLLOWED BY A COLD FRONT THAT WILL COME THROUGH
MONDAY NIGHT.
ODDLY SITUATED MID LEVEL PATTERN IN PLACE WITH A TROUGH AND TWO
EMBEDDED VORT MAXES EXTENDING WEST FROM THE EASTERN GREAT LAKES
TOWARD NEVADA WITH A CUT OFF RIDGE SET UP ALONG THE US/CANADA
BORDER FROM THE PACIFIC NORTHWEST GOING EAST TOWARD THE DAKOTAS.
AT THE SURFACE...A BROAD RIDGE OF HIGH PRESSURE IS IN PLACE ALONG
THE EASTERN ROCKIES/WESTERN PLAINS WITH A RIDGE AXIS EXTENDING EAST
THROUGH THE UPPER MISSISSIPPI RIVER VALLEY AND GREAT LAKES REGION.
TWO MAIN POCKETS OF STRATUS REMAIN TRAPPED UNDER THE 950-900MB
INVERSION WITH ONE ADVANCING SOUTH-SOUTHEAST ACROSS MINNESOTA AND
ANOTHER OVER THE UPPER PENINSULA OF MICHIGAN AND NORTHEAST
WISCONSIN ADVANCING SOUTH-SOUTHWEST ACROSS EASTERN WISCONSIN.
WHAT HAPPENS WITH THIS CLOUD DECK TODAY IS THE MAIN QUESTION SINCE
IT WILL HAVE A DIRECT IMPACT ON HOW HIGH TEMPERATURES GET ONCE
AGAIN. BASED ON THE 05.06Z HRRR AND RECENT IR SATELLITE
TRENDS...IT LOOKS LIKE THE MINNESOTA STRATUS WILL HOLD ON THROUGH
THE MORNING ACROSS MN/IA WITH THE WISCONSIN STRATUS REACHING THE
MISSISSIPPI RIVER BY LATE MORNING. WHILE SOME HOLES WILL LIKELY
FORM THROUGH THE DAY...WENT A BIT ON THE PESSIMISTIC SIDE FOR
CLOUD COVER TODAY WHICH IN TURN WILL KEEP TEMPERATURES DOWN.
WHERE THE HOLES DO OPEN UP TODAY...HIGHS WILL LIKELY END UP IN THE
LOW TO MID 40S WITH TEMPERATURES IN THE 30S UNDER THE CLOUD DECK.
SOME INCREASING WESTERLY WINDS WILL PUSH DOWN ACROSS NORTHERN
WISCONSIN TODAY AND TONIGHT AND MAY HELP TO MIX OUT SOME OF THIS
LOW STRATUS AND CLEAR SKIES FROM THE NORTH.
THE FOCUS THEN GOES TO A COLD FRONT THAT WILL DROP THROUGH THE
REGION ON MONDAY NIGHT. AHEAD OF IT...WARM AIR ADVECTION AND
INCREASED LOW LEVEL MIXING WILL LEAD TO SUNNY SKIES AND A MILD DAY
WITH HIGHS LIKELY TO REACH THE MID TO UPPER 40S. THE TIMING OF THE
COLD FRONT PASSAGE MONDAY AFTERNOON AND NIGHT IS PRETTY CONSISTENT
BETWEEN THE 05.00Z MODEL SOLUTIONS WITH THE FRONT GETTING SOUTH
OF LA CROSSE AND ROCHESTER BEFORE 00Z TUESDAY AND SOUTH OF THE
WISCONSIN STATE LINE BY 06Z. LOW LEVEL CLOUD COVER WILL BE ON THE
INCREASE AS THE FRONT PASSES WITH THE QUESTION NOW BEING WHETHER
ANY FLURRIES WILL BE POSSIBLE AS THIS FEATURE PASSES. 05.00Z
NAM/GFS SOUNDINGS ARE TRENDING TOWARD HAVING A DEEPER LOW LEVEL
MIXED TEMPERATURE PROFILE WITH A DECENT AMOUNT OF MOISTURE AND
LIFT IN THIS LAYER AVAILABLE TO POSSIBLY PRODUCE SOME SNOWFLAKES
AS THE LAYER COOLS TOWARD -10/-12C. CONFIDENCE IS NOT THAT HIGH AT
THIS POINT TO PUT THESE POSSIBLE FLURRIES IN THE FORECAST...BUT IT
IS AT LEAST SOMETHING TO KEEP TABS ON OVER THE NEXT FEW DAYS.
A BROAD RIDGE OF HIGH PRESSURE WILL MOVE INTO THE UPPER
MISSISSIPPI RIVER VALLEY TUESDAY INTO WEDNESDAY AND WILL KEEP
TEMPERATURES DOWN TOWARD NORMAL INTO MID WEEK.
.LONG TERM...WEDNESDAY NIGHT THROUGH SATURDAY
249 AM CST SUN FEB 5 2012
FOCUS IN THE EXTENDED CONTINUES TO BE WITH A COLD FRONT THAT IS
PROGGED TO COME THROUGH LATER IN THE WEEK. THE 05.00Z GFS
CONTINUES ITS TREND OF BEING THE FASTEST WITH THIS FEATURE AND
BRINGS IT THROUGH EARLY ON THURSDAY WHILE THE 05.00Z ECMWF IS
STILL SLOWER AND DOES NOT DROP THE FRONT THROUGH UNTIL FRIDAY.
INTRODUCED SOME LIGHT SNOW CHANCES ACROSS NORTH CENTRAL WISCONSIN
WITH THIS FEATURE AS THE GFS HAS BEEN SHOWING SOME POSSIBLE QPF UP
THERE THE PAST FEW RUNS.
OTHERWISE DIFFERENCES CROP UP GOING INTO THE WEEKEND WITH HOW LONG
THE COLD LOW LEVEL AIR REMAINS IN PLACE WITH THE 05.00Z GFS NOW
HOLDING ONTO 850MB TEMPERATURES BELOW -20C INTO THE WEEKEND WHILE
THE 05.00Z ECMWF PUSHING THE COLD AIR RAPIDLY OFF TO THE EAST LOW
LEVEL WARM AIR ADVECTION KICKING IN BY SATURDAY. GIVEN THESE
DISCREPANCIES...CONFIDENCE IS NOT ALL THAT HIGH IN HOW
TEMPERATURES WILL END UP TOWARD THE LATER PORTION OF THE FORECAST
PACKAGE.
&&
.AVIATION...THROUGH 18Z MONDAY
1156 AM CST SUN FEB 5 2012
FORECAST AGAIN DEALS WITH STRATUS. AS OF 18Z SUNDAY...STRATUS
EXISTS ACROSS ABOUT THE SOUTHERN 2/3 OF MINNESOTA AND MOST OF
IOWA...INCLUDING ADJACENT AREAS OF WISCONSIN. CEILINGS RANGE FROM
LIFR TO IFR WITH VISIBILITIES NOW MOSTLY MVFR. DAYTIME MIXING AND
A GRADUAL INCREASING WEST WIND WILL LIKELY ERODE SOME OF THE
STRATUS THROUGH TONIGHT...ESPECIALLY ALONG AND NORTH OF I-94.
FOR THE TAF SITES...THE INCREASING WEST WIND REALLY DOES NOT OCCUR
UNTIL TONIGHT. WITHOUT THE DAYTIME MIXING HELPING OUT...THE
INCREASING WEST WIND MAY NOT BE ENOUGH TO ERODE THE STRATUS. THIS
IS IN AGREEMENT WITH MODEL FORECASTS TOO. THEREFORE...HAVE WENT
MUCH MORE PESSIMISTIC WITH THE AVIATION FORECAST. LOOKS LIKE
AROUND 15-16Z MONDAY...THE CLOUDS SHOULD SCATTER OUT AT THE TAF
SITES DUE TO A COMBINATION OF THE DAYTIME MIXING...THE WESTERLY
WINDS AND AN APPROACHING COLD FRONT FROM THE NORTH. LOOKING
AHEAD...ADDITIONAL LOW STRATUS APPEARS POSSIBLE ONCE THE COLD FRONT
PASSES LATE MONDAY.
IF THE STRATUS OVER SOUTHWEST AND SOUTH CENTRAL MINNESOTA CAN
DISSIPATE MORE THAN EXPECTED...THEN CLEARING WOULD COME INTO
THE TAF SITES EARLIER...PROBABLY MORE 03-04Z.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
249 AM CST SUN FEB 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS GREEN BAY WI
1142 AM CST SUN FEB 5 2012
UPDATED AVIATION PORTION FOR 18Z TAF ISSUANCE
.SHORT TERM...TODAY THROUGH MONDAY...CLOUD TRENDS ARE THE MAIN FCST
CONCERN.
A S/W TROF BRUSHING PAST TO OUR NE HAS HELPED TO PUSH A WEAK COLD
FRONT THROUGH THE REGION. LOW CLOUDS HAVE INVADED THE NORTHERN
AND EASTERN PARTS OF CWAIN THE WAKE OF THE FRONT...BUT WERE HAVING
A HARD TIME SPREADING INTO CENTRAL WI. A LARGE EXPANSE OF VERY LOW
STRATUS AND FOG WAS ALSO SITUATED OVER MN...AND WAS STARTING TO
CROSS THE WI BORDER.
LOW-LEVEL WINDS ARE EXPECTED TO BECOME WESTERLY BY THIS AFTERNOON...
WHICH SHOULD PUSH THE CURRENT BATCH OF LOW CLOUDS OUT OF GRB CWA.
THIS IS DEPICTED FAIRLY WELL BY THE RUC MODEL. BIG QUESTION IS
WHETHER THE STRATUS OVER MN WILL MAKE A RUN AT THE FORECAST AREA
LATER TODAY INTO TONIGHT. MODELS DO NOT HAVE GOOD HANDLE ON THIS
SCENARIO...AND DON`T OFFER MUCH ASSISTANCE WITH THIS ASPECT OF THE
FCST. WOULD TEND TO BELIEVE THAT THE EASTERN EDGE OF THIS CLOUD
DECK WOULD ERODE DUE TO DAYTIME MIXING...BUT LIKELY REFORM TONIGHT...
AND EDGE INTO NC/C WI. STIFF WESTERLY DOWNSLOPE WINDS (25-30 KTS
AT 925 MB) SHOULD PREVENT THE STRATUS FROM REACHING NE/EC WI.
BASED ON LOW CONFIDENCE...WILL ONLY MENTION PARTLY CLOUDY SKIES
FOR NC/C WI TONIGHT.
A COLD FRONT IS EXPECTED TO SWEEP SOUTHEAST ACROSS THE FORECAST
AREA ON MONDAY...WITH ANOTHER SURGE OF LOW CLOUDS DROPPING INTO
NC/NE WI DURING THE AFTERNOON. NORTH FLOW OFF LAKE SUPERIOR MAY
LEAD TO SOME FLURRIES OR FREEZING DRIZZLE OVER FAR NORTHERN WI
LATE IN THE DAY.
USED A BLEND OF VARIOUS GUIDANCE SETS FOR TEMPERATURES...WHICH
WILL REMAIN WELL ABOVE NORMAL THROUGH MONDAY. THE COLD FRONT WILL
BRING A RETURN TO MORE NORMAL TEMPERATURES BY MONDAY NIGHT/TUESDAY.
.LONG TERM...MONDAY NIGHT THROUGH SATURDAY.
MEAN UPPER LEVEL FLOW ACROSS THE REGION SHOULD BE FROM THE
NORTHWEST WITH THE HIGH AMPLITUDE RIDGE WEST OF THE ROCKIES.
PRECIPITATION DURING THE PERIOD SHOULD BE MAINLY FROM LAKE EFFECT
DUE TO LACK OF SIGNIFICANT MOISTURE WITH SYSTEMS MOVING ACROSS THE
UPPER GREAT LAKES REGION. COLDER AIR WILL MAKE ITS WAY INTO THE
REGION BUT TEMPERATURES SHOULD NOT BE MUCH BELOW NORMAL...EVEN ON
THE COLDEST NIGHTS AND DAYS.
HAVE A CHANCE OF SNOW SHOWERS NEAR THE UPPER MICHIGAN BORDER ON
MONDAY NIGHT IN COLD ADVECTION BEHIND A SURFACE COLD FRONT WITH AN
ASSIST FROM A PASSING UPPER LEVEL TROUGH. THIS SHOULD COME TO AN
END EARLY ON TUESDAY AS SURFACE HIGH PRESSURE BUILDS INTO THE
REGION. EXPECT LOWS TO BE NEAR OR A BIT BELOW NORMAL ON TUESDAY
NIGHT WITH THE SURFACE HIGH AND UPPER LEVEL RIDGE OVER THE AREA.
RETURN FLOW AND PLENTY OF SUNSHINE ON WEDNESDAY SHOULD ALLOW
TEMPERATURES TO RISE ABOVE NORMAL ONCE AGAIN...UNTIL ANOTHER SHOT
OF COLDER AIR IMPACTS THE FORECAST AREA BEHIND THE NEXT COLD
FRONT MOVING THROUGH ON THURSDAY. EXPECT BELOW NORMAL TEMPERATURES
ON FRIDAY AND SATURDAY. HAVE LOW END CHANCE OR HIGH END SLIGHT
CHANCE POPS GOING FOR NORTH CENTRAL WISCONSIN AND THE LAKESHORE AT
TIMES THROUGH THE END OF THE FORECAST PERIOD DUE TO POSSIBLE LAKE
EFFECT SNOW SHOWERS.
&&
.AVIATION...MVFR CIGS ACROSS NORTH CENTRAL AND CENTRAL WISCONSIN
NORTH OF KISW WERE ERODING LATE THIS MORNING WITH ONLY A FEW PATCHES
WEST OF KAUW. THESE LOW CLOUDS SHOULD DISAPPEAR EARLY THIS AFTERNOON.
IFR/MVFR CIGS AND VISIBILITIES WERE LURKING ACROSS WESTERN WISCONSIN
AND NORTHEAST IOWA AND HAVE SHOWN A SLOW EASTWARD ADVANCEMENT OVER
THE PAST FEW HOURS. MVFR CIGS ACROSS NORTHEAST WISCONSIN WERE A
LITTLE SLOWER TO CLEAR. SATELLITE IMAGERY WOULD SUGGEST THIS AREA
WOULD GRADUALLY CLEAR FROM WEST TO EAST DURING THE AFTERNOON
HOURS.
MAIN QUESTION FOR TONIGHT IS WHAT WILL HAPPEN TO THE LOW CLOUDS
ACROSS WESTERN WISCONSIN...MINNESOTA AND NORTHEAST IOWA. SATELLITE
IMAGERY INDICATED THAT THE CLOUDS WERE BREAKING UP IN SOME AREAS OF
MINNESOTA. LOW LEVEL WINDS ARE EXPECTED TO TURN TO THE WEST AND
THE THOUGHT IS THAT THE LOW CLOUDS WOULD ADVECT BACK INTO
CENTRAL/NORTH CENTRAL WISCONSIN LATE THIS AFTERNOON OR EARLY
THIS EVENING...THEN ACROSS NORTHEAST WISCONSIN LATER THIS EVENING
INTO THE OVERNIGHT HOURS. THIS THOUGHT WAS SHARED BY THE AVIATION
FORECASTERS AT KMKX/KARX. HOWEVER...NUMERICAL GUIDANCE AND THE
CANADIAN MODEL SUGGEST THE LOW CLOUDS WOULD NOT DEVELOP UNTIL
LATE TONIGHT ACROSS NORTHEAST WISCONSIN AND WOULD NOT DEVELOP AT ALL
ACROSS NORTH CENTRAL WISCONSIN. DECIDED TO GO MORE PESSIMISTIC IN CLOUD
COVER THAN THE NUMERICAL GUIDANCE WOULD SUGGEST. THE NEXT QUESTION
IS WHEN WILL THE LOW CLOUDS BREAK UP. INCREASING WIND SHEAR JUST ABOVE
THE SURFACE MAY PROVIDE ENOUGH MIXING TO BRING DRIER AIR DOWN TO THE
SURFACE AND BREAK UP THE CLOUDS. HAVE LOW CLOUDS EXITING THE AREA LATE
TONIGHT OR EARLY MONDAY MORNING. CURRENT FORECAST IN THE LOW
CLOUDS LEAVING THE AREA IS LOW. ON MONDAY AFTERNOON...THERE IS SOME
POTENTIAL FOR FREEZING DRIZZLE OR FLURRIES MONDAY AFTERNOON...WITH
SOME FLURRIES ACROSS THE NORTH MONDAY NIGHT.
ECKBERG
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$