Forecast Discussions mentioning any of
"HRRR" "RR" "RUC13" "RUC" received at GSD on 02/06/12
AREA FORECAST DISCUSSION
NWS ALBANY NY
1252 AM EST SAT FEB 4 2012
.SYNOPSIS...
A WEAKENING COLD FRONT WILL MOVE SOUTH ACROSS THE AREA
OVERNIGHT WITH ONLY A CHANCE OF SOME SNOW SHOWERS ACROSS THE
SOUTHERN ADIRONDACKS. OTHERWISE...HIGH PRESSURE WILL DOMINATE FOR
THE WEEKEND WITH TEMPERATURES NEAR NORMAL TO SLIGHTLY ABOVE NORMAL
FOR EARLY FEBRUARY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AREA OF CLOUDS AND FLURRIES STILL OVER THE REGION...AND BASED ON
OBSERVATIONS AND TRENDS...FEW CHANGES NEEDED IF ANY THROUGH SUNRISE.
PREV AFD BELOW...
AS OF 930 PM EST...THE LATEST REGIONAL MOSAIC RADAR...AND THE KTYX
RADAR HAS SHOWN AN INCREASE IN REFLECTIVITIES OVER THE TUG HILL
PLATEAU AND THE WRN DACKS /NRN HERKIMER AND NW HAMILTON COUNTIES/...
AS THE COLD FRONT HAS REACHED THE WRN SHORES OF LAKE ONTARIO...AND
THE ST LAWRENCE RIVER VALLEY. WE INCREASED THE POPS TO LIKELY
VALUE FOR AN INCH OR TWO OF SNOW OVER THE WRN DACKS OVER THE NEXT
FEW HOURS. THE LATEST NAM AND HRRR STILL SHOWS THE FRONT LACKING
GOOD MOISTURE CONVERGENCE FOR MUCH IN THE VALLEYS...AND ESPECIALLY
FROM THE CAPITAL REGION SOUTH AND EAST. WE KEPT SOME SLIGHT AND
LOW CHC POPS OVER THE SRN GREENS...NRN AND ERN CATSKILLS..AND THE
WRN MOHAWK VALLEY UNTIL SHORTLY AFTER MIDNIGHT. THE CLOUDS
THICKENED AND LOWERED QUICKLY OVER THE SRN ZONES. WE INCREASED THE
CLOUD COVER EVEN MORE OVERNIGHT...AND GRADUALLY TAPERED TO PARTLY
CLOUDY CONDITIONS TOWARDS DAYBREAK...AS DRIER AIR FILTERS IN THE
WAKE OF THE BOUNDARY FROM NW TO SE. WE ALSO BROUGHT UP TEMPS A
COUPLE OF DEGREES FROM THE CAPITAL REGION SOUTH AND EAST WITH THE
CLOUD COVER PERSISTING A LITTLE LONGER.
PREVIOUS NEAR TERM UPDATE...
AS OF 655 PM EST...ONGOING FORECAST IS IN PRETTY GOOD SHAPE WITH
APPROACHING COLD FRONT FROM THE ST LAWRENCE RIVER VALLEY. AN H500
VORT MAX MOVING ACROSS NRN NY /VIA THE LATEST RUC40/ AHEAD OF THE
FRONT HAS FOCUSED SOME SCT SNOW SHOWERS/FLURRIES OVER THE
ADIRONDACKS...AND WRN MOHAWK VALLEY. WE RETOOLED POPS BASED ON THE
TRENDS...AND SPED UP THE TIMING OF THE CLOUDS WITH THE VORT MAX
AND FRONT BASED ON THE IR LOOP. T/TD/RH/APPARENT TEMP TRENDS RETOOLED
BASED ON THE OBSERVATIONS THE PAST FEW HOURS.
PREVIOUS NEAR TERM...
A WEAKENING COLD FRONT WILL SLOWLY DROP SOUTH FROM SAINT LAWRENCE
VALLEY THIS EVENING INTO THE CENTRAL NEW YORK SHORTLY AFTER
MIDNIGHT AND ACROSS THE SOUTHERN TIER BY DAYBREAK. THIS SYSTEM HAS
VERY LITTLE MOISTURE WITH IT AND IS EXPECTED TO ONLY IMPACT AREAS
NORTH OF THE MOHAWK VALLEY WITH AROUND AN INCH POSSIBLE ACROSS THE
WESTERN ADIRONDACKS. LOWS OVERNIGHT ARE EXPECTED TO RANGE FROM THE
MID TEENS NORTHWEST TO MID 20S SOUTHEAST WITH GENERALLY MOSTLY
CLOUDY SKIES...EXCEPT PARTLY CLOUDY EXTREME SOUTHEAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
FOR THE PERIOD FROM SATURDAY THROUGH SUNDAY NIGHT EXPECT DRY
WEATHER ACROSS THE FA WITH A FAIRLY LARGE RIDGE OF HIGH PRESSURE
BUILDING ACROSS THE REGION WHICH WILL KEEP THE SYSTEM TRACKING
FROM THE MID MISSISSIPPI VALLEY TO THE VIRGINIA COAST FAR ENOUGH
SOUTH OF OUR REGION SUCH THAT THE NORTHERN EDGE OF THE PCPN SHIELD
IS EXPECTED TO REMAIN SOUTH OF NEW YORK STATE. THE RIDGE OF HIGH
PRESSURE IS ASSOCIATED WITH A SEASONABLE AIRMASS...ALTHOUGH TEMPS
SATURDAY NIGHT MAY BE A LITTLE COLDER THAN RECENT NIGHTS AS WEAK
COLD AIR ADVECTION IS EXPECTED DURING THE NIGHT. HIGHS ON SATURDAY
AND SUNDAY ARE EXPECTED TO RANGE FROM THE UPPER 20S NORTHWEST TO
AROUND 40 SOUTHEAST WITH SATURDAY BEING THE SLIGHTLY WARMER OF THE
2 DAYS. LOWS SATURDAY NIGHT ARE EXPECTED TO RANGE FROM THE SINGLE
DIGITS NORTHWEST TO UPPER TEENS TO AROUND 20 SOUTHEAST WITH LOWS
SUNDAY NIGHT IN THE UPPER SINGLE DIGITS NORTHWEST TO LOWER 20S
SOUTHEAST.
MONDAY IS EXPECTED TO BE THE WARMEST DAY OF THE SHORT TERM PERIOD
AS THE AIRMASS MODIFIES WITH A WARM FRONT MOVING ACROSS SOUTHERN
CANADA. EXPECT HIGHS ON MONDAY TO RANGE FROM THE UPPER 30S
NORTHWEST TO UPPER 40S SOUTHEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE PATTERN OF NO SIGNIFICANT STORM DEVELOPMENT CONTINUES. HIGH
PRESSURE WILL DOMINATE FOR MOST OF THE PERIOD...WITH A COUPLE OF
WEAK COLD FRONTAL BOUNDARIES PROVIDING THE IMPETUS FOR POSSIBLE
SHOWER ACTIVITY...THE GREATEST PROBABILITY OF THIS BEING ON FRIDAY.
THE FIRST COLD FRONT ON TUESDAY WILL LIKELY LIMIT SHOWER ACTIVITY...
IN THE FORM OF SNOW...TO THE WESTERN ADIRONDACKS...WHILE FRIDAY/S
EVENT MAY BE A MORE WIDESPREAD MIXED EVENT...YET STILL BE
MOISTURE-STARVED.
HIGH TEMPERATURES WILL AVERAGE SLIGHTLY ABOVE NORMAL...WITH HIGHS
BOTH TUESDAY AND WEDNESDAY RANGING FROM THE MID AND UPPER 20S IN THE
MOUNTAINS...TO THE UPPER 30S OR LOWER 40S IN THE MID HUDSON VALLEY.
THE NORTHERN AND MOUNTAIN ZONES WILL EXPERIENCE MODERATING
TEMPERATURES BY FRIDAY...WITH HIGHS IN THE LOWER AND MID 30S.
HUDSON VALLEY HIGH TEMPERATURES BY FRIDAY WILL BE GENERALLY IN THE
LOWER 40S. TUESDAY NIGHT WILL BE THE COLDEST NIGHT OF THE PERIOD...
WITH LOWS RANGING FROM AROUND ZERO IN THE ADIRONDACKS AND GREENS...
TO AROUND 20 DEGREES IN THE MID HUDSON VALLEY. THEN A SLOW
MODERATION ENSUES...AND BY THE END OF THE WORK WEEK...LOWS IN THE
TEENS WILL BE CONFINED TO THE HIGHEST POINTS OF THE ADIRONDACKS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A WEAK COLD FRONT WILL MOVE SOUTHEAST FROM THE ST LAWRENCE RIVER
VALLEY TONIGHT. IT WILL BE SOUTH OF THE REGION BY AROUND SUNRISE
THIS MORNING...AS HIGH PRESSURE WILL BUILD IN FROM QUEBEC FOR MUCH
OF THE WEEKEND.
CLOUDS HAVE ENCOMPASSED THE AREA...WITH MAINLY VFR CIGS AND VSBYS.
BRIEF PERIODS OF MVFR CIGS AT KGFL/KALB THROUGH 09Z. WILL ALSO
MENTION VCSH FOR A FEW POSSIBLE LIGHT FLURRIES AT KGFL/KALB. THE
SKIES WILL CLEAR FROM NORTH TO SOUTH WITH THE DRY COLD FRONTAL
PASSAGE BY DAYBREAK. A FEW-SCT STRATOCUMULUS WILL BE ACROSS ERN NY
WITH VFR CONDITIONS DOMINATING THROUGH THE EVENING.
WINDS WILL INITIALLY BE WEST-SOUTHWEST AROUND 3-6 KT BEFORE THE COLD
FRONT PASSES THROUGH...WITH WINDS SHIFTING TO THE NORTHWEST BEHIND
THE FRONT BY SUNRISE. WINDS SPEEDS INCREASE TO AROUND 6-10 KTS BY
LATE THIS MORNING.
OUTLOOK...
SUN NIGHT-MON...MAINLY VFR. NO SIG WX.
MON NIGHT-TUE...VFR. SLIGHT CHC OF -SHSN.
TUE NIGHT-WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
HYDRO PROBLEMS ARE NOT ANTICIPATED THROUGH EARLY NEXT WEEK WITH
LITTLE IF ANY PRECIPITATION EXPECTED EXCEPT FOR SOME LIGHT SNOW
SHOWERS ACROSS THE NORTHERN MOUNTAINS TONIGHT. TEMPERATURES ARE
EXPECTED TO BE NORMAL TO SLIGHTLY ABOVE NORMAL OVER THE
WEEKEND. SOME GAGES ARE STILL BEING IMPACTED BY ICE ACROSS
NORTHERN PORTIONS OF THE HSA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
AVIATION...JPV
AREA FORECAST DISCUSSION
NWS ALBANY NY
1229 AM EST SAT FEB 4 2012
.SYNOPSIS...
A WEAKENING COLD FRONT WILL MOVE SOUTH ACROSS THE AREA
OVERNIGHT WITH ONLY A CHANCE OF SOME SNOW SHOWERS ACROSS THE
SOUTHERN ADIRONDACKS. OTHERWISE...HIGH PRESSURE WILL DOMINATE FOR
THE WEEKEND WITH TEMPERATURES NEAR NORMAL TO SLIGHTLY ABOVE NORMAL
FOR EARLY FEBRUARY.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AREA OF CLOUDS AND FLURRIES STILL OVER THE REGION...AND BASED ON
OBSERVATIONS AND TRENDS...FEW CHANGES NEEDED IF ANY THROUGH SUNRISE.
PREV AFD BELOW...
AS OF 930 PM EST...THE LATEST REGIONAL MOSAIC RADAR...AND THE KTYX
RADAR HAS SHOWN AN INCREASE IN REFLECTIVITIES OVER THE TUG HILL
PLATEAU AND THE WRN DACKS /NRN HERKIMER AND NW HAMILTON COUNTIES/...
AS THE COLD FRONT HAS REACHED THE WRN SHORES OF LAKE ONTARIO...AND
THE ST LAWRENCE RIVER VALLEY. WE INCREASED THE POPS TO LIKELY
VALUE FOR AN INCH OR TWO OF SNOW OVER THE WRN DACKS OVER THE NEXT
FEW HOURS. THE LATEST NAM AND HRRR STILL SHOWS THE FRONT LACKING
GOOD MOISTURE CONVERGENCE FOR MUCH IN THE VALLEYS...AND ESPECIALLY
FROM THE CAPITAL REGION SOUTH AND EAST. WE KEPT SOME SLIGHT AND
LOW CHC POPS OVER THE SRN GREENS...NRN AND ERN CATSKILLS..AND THE
WRN MOHAWK VALLEY UNTIL SHORTLY AFTER MIDNIGHT. THE CLOUDS
THICKENED AND LOWERED QUICKLY OVER THE SRN ZONES. WE INCREASED THE
CLOUD COVER EVEN MORE OVERNIGHT...AND GRADUALLY TAPERED TO PARTLY
CLOUDY CONDITIONS TOWARDS DAYBREAK...AS DRIER AIR FILTERS IN THE
WAKE OF THE BOUNDARY FROM NW TO SE. WE ALSO BROUGHT UP TEMPS A
COUPLE OF DEGREES FROM THE CAPITAL REGION SOUTH AND EAST WITH THE
CLOUD COVER PERSISTING A LITTLE LONGER.
PREVIOUS NEAR TERM UPDATE...
AS OF 655 PM EST...ONGOING FORECAST IS IN PRETTY GOOD SHAPE WITH
APPROACHING COLD FRONT FROM THE ST LAWRENCE RIVER VALLEY. AN H500
VORT MAX MOVING ACROSS NRN NY /VIA THE LATEST RUC40/ AHEAD OF THE
FRONT HAS FOCUSED SOME SCT SNOW SHOWERS/FLURRIES OVER THE
ADIRONDACKS...AND WRN MOHAWK VALLEY. WE RETOOLED POPS BASED ON THE
TRENDS...AND SPED UP THE TIMING OF THE CLOUDS WITH THE VORT MAX
AND FRONT BASED ON THE IR LOOP. T/TD/RH/APPARENT TEMP TRENDS RETOOLED
BASED ON THE OBSERVATIONS THE PAST FEW HOURS.
PREVIOUS NEAR TERM...
A WEAKENING COLD FRONT WILL SLOWLY DROP SOUTH FROM SAINT LAWRENCE
VALLEY THIS EVENING INTO THE CENTRAL NEW YORK SHORTLY AFTER
MIDNIGHT AND ACROSS THE SOUTHERN TIER BY DAYBREAK. THIS SYSTEM HAS
VERY LITTLE MOISTURE WITH IT AND IS EXPECTED TO ONLY IMPACT AREAS
NORTH OF THE MOHAWK VALLEY WITH AROUND AN INCH POSSIBLE ACROSS THE
WESTERN ADIRONDACKS. LOWS OVERNIGHT ARE EXPECTED TO RANGE FROM THE
MID TEENS NORTHWEST TO MID 20S SOUTHEAST WITH GENERALLY MOSTLY
CLOUDY SKIES...EXCEPT PARTLY CLOUDY EXTREME SOUTHEAST.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH MONDAY/...
FOR THE PERIOD FROM SATURDAY THROUGH SUNDAY NIGHT EXPECT DRY
WEATHER ACROSS THE FA WITH A FAIRLY LARGE RIDGE OF HIGH PRESSURE
BUILDING ACROSS THE REGION WHICH WILL KEEP THE SYSTEM TRACKING
FROM THE MID MISSISSIPPI VALLEY TO THE VIRGINIA COAST FAR ENOUGH
SOUTH OF OUR REGION SUCH THAT THE NORTHERN EDGE OF THE PCPN SHIELD
IS EXPECTED TO REMAIN SOUTH OF NEW YORK STATE. THE RIDGE OF HIGH
PRESSURE IS ASSOCIATED WITH A SEASONABLE AIRMASS...ALTHOUGH TEMPS
SATURDAY NIGHT MAY BE A LITTLE COLDER THAN RECENT NIGHTS AS WEAK
COLD AIR ADVECTION IS EXPECTED DURING THE NIGHT. HIGHS ON SATURDAY
AND SUNDAY ARE EXPECTED TO RANGE FROM THE UPPER 20S NORTHWEST TO
AROUND 40 SOUTHEAST WITH SATURDAY BEING THE SLIGHTLY WARMER OF THE
2 DAYS. LOWS SATURDAY NIGHT ARE EXPECTED TO RANGE FROM THE SINGLE
DIGITS NORTHWEST TO UPPER TEENS TO AROUND 20 SOUTHEAST WITH LOWS
SUNDAY NIGHT IN THE UPPER SINGLE DIGITS NORTHWEST TO LOWER 20S
SOUTHEAST.
MONDAY IS EXPECTED TO BE THE WARMEST DAY OF THE SHORT TERM PERIOD
AS THE AIRMASS MODIFIES WITH A WARM FRONT MOVING ACROSS SOUTHERN
CANADA. EXPECT HIGHS ON MONDAY TO RANGE FROM THE UPPER 30S
NORTHWEST TO UPPER 40S SOUTHEAST.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE PATTERN OF NO SIGNIFICANT STORM DEVELOPMENT CONTINUES. HIGH
PRESSURE WILL DOMINATE FOR MOST OF THE PERIOD...WITH A COUPLE OF
WEAK COLD FRONTAL BOUNDARIES PROVIDING THE IMPETUS FOR POSSIBLE
SHOWER ACTIVITY...THE GREATEST PROBABILITY OF THIS BEING ON FRIDAY.
THE FIRST COLD FRONT ON TUESDAY WILL LIKELY LIMIT SHOWER ACTIVITY...
IN THE FORM OF SNOW...TO THE WESTERN ADIRONDACKS...WHILE FRIDAY/S
EVENT MAY BE A MORE WIDESPREAD MIXED EVENT...YET STILL BE
MOISTURE-STARVED.
HIGH TEMPERATURES WILL AVERAGE SLIGHTLY ABOVE NORMAL...WITH HIGHS
BOTH TUESDAY AND WEDNESDAY RANGING FROM THE MID AND UPPER 20S IN THE
MOUNTAINS...TO THE UPPER 30S OR LOWER 40S IN THE MID HUDSON VALLEY.
THE NORTHERN AND MOUNTAIN ZONES WILL EXPERIENCE MODERATING
TEMPERATURES BY FRIDAY...WITH HIGHS IN THE LOWER AND MID 30S.
HUDSON VALLEY HIGH TEMPERATURES BY FRIDAY WILL BE GENERALLY IN THE
LOWER 40S. TUESDAY NIGHT WILL BE THE COLDEST NIGHT OF THE PERIOD...
WITH LOWS RANGING FROM AROUND ZERO IN THE ADIRONDACKS AND GREENS...
TO AROUND 20 DEGREES IN THE MID HUDSON VALLEY. THEN A SLOW
MODERATION ENSUES...AND BY THE END OF THE WORK WEEK...LOWS IN THE
TEENS WILL BE CONFINED TO THE HIGHEST POINTS OF THE ADIRONDACKS.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A WEAK COLD FRONT WILL MOVE SOUTHEAST FROM THE ST LAWRENCE RIVER
VALLEY TONIGHT. IT WILL BE SOUTH OF THE REGION BY TOMORROW
MORNING...AS HIGH PRESSURE WILL BUILD IN FROM S-CNTRL QUEBEC FOR
MUCH OF THE WEEKEND.
CLOUDS WILL INCREASE AND LOWER FROM NORTH TO SOUTH TONIGHT.
EXPECTING MAINLY VFR CIGS AND VSBYS...WITH A BRIEF PERIOD OF MVFR
CIGS AT KGFL BTWN 03Z-06Z. THE SKIES WILL CLEAR FROM NORTH TO SOUTH
WITH THE DRY COLD FRONTAL PASSAGE BY DAYBREAK TOMORROW. A FEW-SCT
STRATOCUMULUS WILL BE ACROSS ERN NY WITH VFR CONDITIONS DOMINATING
INTO THE AFTERNOON.
THE WINDS WILL BE LIGHT AND VARIABLE AT KGFL AND KPOU TONIGHT AT
LESS THAN 5 KTS...WITH W/NW WINDS AT KALB OF 5-9 KTS. THE WINDS
WILL INCREASE FROM THE N/NW AT 5-10 KTS LATE TOMORROW MORNING INTO
THE AFTERNOON AT ALL THE TAF SITES.
OUTLOOK...
SAT NIGHT-MON...MAINLY VFR. NO SIG WX.
MON NIGHT-TUE...VFR. SLIGHT CHC OF -SHSN.
TUE NIGHT-WED...VFR. NO SIG WX.
&&
.HYDROLOGY...
HYDRO PROBLEMS ARE NOT ANTICIPATED THROUGH EARLY NEXT WEEK WITH
LITTLE IF ANY PRECIPITATION EXPECTED EXCEPT FOR SOME LIGHT SNOW
SHOWERS ACROSS THE NORTHERN MOUNTAINS TONIGHT. TEMPERATURES ARE
EXPECTED TO BE NORMAL TO SLIGHTLY ABOVE NORMAL OVER THE
WEEKEND. SOME GAGES ARE STILL BEING IMPACTED BY ICE ACROSS
NORTHERN PORTIONS OF THE HSA.
FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED
AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE
ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
MA...NONE.
VT...NONE.
&&
$$
SYNOPSIS...NAS
NEAR TERM...NAS
AREA FORECAST DISCUSSION
NWS LINCOLN IL
855 PM CST SUN FEB 5 2012
.DISCUSSION...
ISSUED 855 PM CST SUN FEB 5 2012
CLOUD COVER WILL BE ON THE INCREASE AS A LARGE AREA OF LOW LEVEL
MOISTURE MOVES INTO THE AREA FROM THE NORTHWEST. EXCEPT FOR AREAS
IN THE SOUTHEAST...ALL AREAS SHOULD BE CLOUDY BY MORNING. LIGHT
FOG WILL ALSO CONTINUE TO DEVELOP IN AREAS WHERE SKIES ARE
CURRENTLY CLEAR. CLOUDS WILL ALSO HOLD TEMPS UP IN THE WESTERN
HALF OF THE CWA OVERNIGHT. SO WILL BE MAKING ADJUSTMENTS TO THE
GOING FORECAST TO ACCOUNT FOR INCREASING CLOUDS OVERNIGHT AND
WARMER TEMPS. UPDATE SHOULD BE OUT SHORTLY.
AUTEN
&&
.AVIATION...
ISSUED 552 PM CST SUN FEB 5 2012
SKIES WILL BEGIN AS CLEAR BUT CONCERN IS LARGE AREA OF IFR CLOUDS
THAT SHOULD BEGIN TO MOVE SOUTHEAST INTO THE AREA AFTER SUNSET.
SHOULD BEGIN TO AFFECT PIA 04Z...SPI 05Z...BMI 08Z AND DEC/CMI AT
10Z. IFR CONDITIONS ARE WITH CIGS BELOW 1KFT...WHILE VIS SHOULD BE
IN THE MVFR CATEGORY. HRRR MODEL IS ONLY MODEL THAT PICKS UP ON
THIS VERY LOW BOUNDARY LAYER MOISTURE. SO SOME UNCERTAINTY WITH
HOW FAST AND FAR THIS LOW LEVEL MOISTURE WILL GO. BUT FOLLOWING
HRRR ALL SITES WILL SEE THIS ROLE IN DURING THE OVERNIGHT AND EARLY
MORNING HOURS. THEN EXPECT DURING THE MORNING HOURS...CONDITIONS
SHOULD SCATTER OUT AND BECOME MOSTLY CLEAR...GIVEN SHALLOWNESS OF
THE MOISTURE. WINDS WILL BE LIGHT NORTH-NORTHEAST TONIGHT BECOMING
WESTERLY OVERNIGHT AND THEN SOUTHWEST DURING THE MORNING.
AUTEN
&&
.PREV 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
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
552 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 552 PM CST SUN FEB 5 2012
SKIES WILL BEGIN AS CLEAR BUT CONCERN IS LARGE AREA OF IFR CLOUDS
THAT SHOULD BEGIN TO MOVE SOUTHEAST INTO THE AREA AFTER SUNSET.
SHOULD BEGIN TO AFFECT PIA 04Z...SPI 05Z...BMI 08Z AND DEC/CMI AT
10Z. IFR CONDITIONS ARE WITH CIGS BELOW 1KFT...WHILE VIS SHOULD BE
IN THE MVFR CATEGORY. HRRR MODEL IS ONLY MODEL THAT PICKS UP ON
THIS VERY LOW BOUNDARY LAYER MOISTURE. SO SOME UNCERTAINTY WITH
HOW FAST AND FAR THIS LOW LEVEL MOISTURE WILL GO. BUT FOLLOWING
HRRR ALL SITES WILL SEE THIS ROLE IN DURING THE OVERNIGHT AND EARLY
MORNING HOURS. THEN EXPECT DURING THE MORNING HOURS...CONDITIONS
SHOULD SCATTER OUT AND BECOME MOSTLY CLEAR...GIVEN SHALLOWNESS OF
THE MOISTURE. WINDS WILL BE LIGHT NORTH-NORTHEAST TONIGHT BECOMING
WESTERLY OVERNIGHT AND THEN SOUTHWEST DURING THE MORNING.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1159 AM CST SAT FEB 4 2012
.DISCUSSION...
ISSUED 1030 AM CST SAT FEB 4 2012
SHOWERS STILL OVER MUCH OVER CENTRAL ILLINOIS THIS
MORNING...PARTICULARLY STRETCHING FROM THE QUAD CITIES TO
CHAMPAIGN WITH THE MORE MODERATE SHOWERS. LOW PRESSURE CENTER TO
THE SOUTHWEST. CHANGING THE WORDING OF THE FORECAST TO REFLECT THE
LIGHTER SHOWERS/DRIZZLE TO THE SOUTH...AND TONE DOWN THE MAX TEMPS
ACROSS THE NORTH UNDER THE MORE MODERATE PRECIP. MINOR
ADJUSTMENTS...NEW GRIDS AND ZONES OUT MOMENTARILY.
&&
.AVIATION...
ISSUED 1155 AM CST SAT FEB 4 2012
FORECAST REMAINS VERY MUCH IN LINE WITH CURRENT
WEATHER...DEFORMATION AXIS ACROSS NRN TERMINALS PROVIDING FOCUS
FOR RAIN PIA/BMI/CMI...WITH MORE SHOWERY SCT ACTIVITY FURTHER TO
THE SOUTH. SOME IMPROVEMENT FOR THE SOUTH ANTICIPATED AS FAR AS
VIS...THOUGH MANY OF THE CIGS REMAIN CLOSE TO THE IFR/LIFR BREAK
AND WILL LIKELY CONTINUE THROUGH THE DAY AND EVENING. IMPROVEMENT
TO VFR CIGS THIS EVENING...THOUGH STILL UNDER 5KFT...AND MVFR VIS
LIKELY. TIME HEIGHT RH PORTRAYED IN BOTH GFS AND NAM SUGGEST
RETURN OF A DRY AIR COLUMN AND LITTLE IN THE WAY OF CLOUDS
TOMORROW MORNING.
HJS
&&
.PREV DISCUSSION...
ISSUED 200 AM CST SAT FEB 4 2012
SURFACE LOW WAS CENTERED OVER SOUTHWEST MISSOURI EARLY THIS
MORNING...WHILE ASSOCIATED UPPER LOW WAS STILL BACK OVER NORTH
CENTRAL KANSAS. INITIAL BAND OF RAIN HAD ADVANCED INTO EASTERN
ILLINOIS...WITH AREAS WEST OF I-55 TAPERING DOWN TO DRIZZLE. A
WEDGE OF DRIER AIR WAS SEEN ON WATER VAPOR IMAGERY ACROSS
SOUTHEAST KANSAS...ADVECTING INTO MISSOURI.
INITIAL FORECAST CONCERN REVOLVES AROUND THE EXTENT OF RAINFALL
TODAY AND THIS EVENING. LATER ON...POTENTIAL COOL SNAP LATE IN THE
FORECAST PERIOD IS THE FOCUS.
SHORT TERM...TODAY THROUGH MONDAY...
LATEST HRRR SHOWING THE CURRENT BAND OF RAIN SHOULD BE EXITING THE
EASTERN CWA TOWARD SUNRISE...BUT BAND OF PRECIPITATION IN A
BAROCLINIC ZONE ALONG THE I-80 CORRIDOR FROM IOWA TO INDIANA WILL
EXPAND AND SINK A BIT FURTHER SOUTH. FORECAST SOUNDINGS SHOWING
DRY AIR EXPANDING ABOVE 700 MB AS THE DAY PROGRESSES...TRENDING
THE PRECIPITATION INTO MORE OF A DRIZZLE OR VERY LIGHT RAIN. MAIN
SURFACE LOW SHOULD MAKE STEADY PROGRESS EASTWARD INTO THE OHIO
VALLEY BY EVENING...BUT 00Z MODELS SHOWING THE UPPER LOW LAGGING
BEHIND QUITE A BIT THROUGH SUNDAY AND POTENTIALLY EVEN INTO EARLY
MONDAY. WILL LINGER SOME PRECIPITATION INTO THIS EVENING...BUT
PERSISTENT NORTH/NORTHEAST SURFACE FLOW INTO THE AREA WILL
EVENTUALLY TAKE ITS TOLL AND DRY OUT THE LOWER ATMOSPHERE...THUS
WILL KEEP THE FORECAST DRY FOR SUNDAY AND MONDAY DESPITE THE
UPPER LOW BEING RELATIVELY CLOSE BY.
SOUNDINGS KEEP THE CLOUDS FAIRLY THICK TODAY...SO DID NOT SEE A
REASON TO STRAY FROM THE CONSENSUS OF THE TIGHTLY PACKED NUMERICAL
GUIDANCE. TONIGHT IS A BIT TRICKIER...AS THE SPEED OF THE CLEARING
FROM THE NORTH MAY DROP TEMPERATURES QUICKER THAN EXPECTED. FOR
NOW...WILL GO WITH LOWS BELOW FREEZING OVER MOST AREAS NORTH OF
THE I-72 CORRIDOR...WITH 20S QUITE LIKELY ACROSS THE FAR NORTHERN
CWA. TEMPERATURES SUNDAY AND MONDAY WILL ONCE AGAIN BE SEVERAL
DEGREES ABOVE NORMAL.
LONG TERM...TUESDAY THROUGH FRIDAY...
A PIECE OF LEFTOVER ENERGY FROM THE CURRENT UPPER LOW IN THE
PLAINS WILL GET STRANDED OVER THE CENTRAL ROCKIES THIS WEEKEND...
BEFORE FINALLY MOVING EASTWARD INTO THE CENTRAL U.S. BY MIDWEEK.
SPLIT UPPER FLOW WILL KEEP MOISTURE ADVECTION IN OUR AREA RATHER
MINIMAL...SO WILL ONLY GO WITH SLIGHT CHANCES FOR PRECIPITATION...
PRIMARILY ON WEDNESDAY.
IN THE LONGER RANGE...UPPER PATTERN BEGINS TO SHIFT QUITE A BIT AS
A LOW CUTS OFF OVER BAJA CALIFORNIA. ALL OF THE MEDIUM RANGE
MODELS PLACE OUR AREA IN A NORTHWEST FLOW FOR THE LATTER PART OF
THE WORK WEEK...WITH TEMPERATURES NEAR OR EVEN A BIT BELOW NORMAL
FOR A CHANGE. LOBES OF ARCTIC AIR SHOULD SWING ACROSS THE GREAT
LAKES REGION...WITH OUR AREA RECEIVING GLANCING BLOWS WITH
POTENTIAL FOR A MORE SUBSTANTIAL BLAST OF COLD AIR TOWARD NEXT
WEEKEND.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1037 AM CST SAT FEB 4 2012
.DISCUSSION...
ISSUED 1030 AM CST SAT FEB 4 2012
SHOWERS STILL OVER MUCH OVER CENTRAL ILLINOIS THIS
MORNING...PARTICULARLY STRETCHING FROM THE QUAD CITIES TO
CHAMPAIGN WITH THE MORE MODERATE SHOWERS. LOW PRESSURE CENTER TO
THE SOUTHWEST. CHANGING THE WORDING OF THE FORECAST TO REFLECT THE
LIGHTER SHOWERS/DRIZZLE TO THE SOUTH...AND TONE DOWN THE MAX TEMPS
ACROSS THE NORTH UNDER THE MORE MODERATE PRECIP. MINOR
ADJUSTMENTS...NEW GRIDS AND ZONES OUT MOMENTARILY.
HJS
&&
.AVIATION...
ISSUED 515 AM CST SAT FEB 4 2012
IFR TO LIFR CONDITIONS ARE EXPECTED INTO EARLY TONIGHT AS A STORM
SYSTEM SLOWLY PASSES TO OUR SOUTH TODAY. RAIN/DRIZZLE ALONG WITH
THE LOW CIGS WILL BE THE STORY ACRS THE FORECAST AREA TODAY INTO
EARLY TONIGHT...BEFORE DRIER AIR FILTERS SOUTH INTO CENTRAL IL
BRINGING VFR CONDITIONS TO THE AREA AFTR 06Z. CIGS WILL RANGE
FROM AS LOW AS AROUND 300 FEET...ESPECIALLY AT KBMI...TO 700 FEET
AT MOST OF THE OTHER TAF LOCATIONS. OCCASIONALLY WE MAY SEE THE
CIGS GO ABOVE 1000 FEET FOR A BRIEF TIME BUT FOR THE MOST PART...
WHAT WE ARE SEEING ON SATELLITE AND WITH SFC OBS TO OUR WEST AND
SOUTHWEST DOESN`T LEND MUCH HOPE FOR ANYTHING PROLONGED ABOVE
1000 FEET TODAY.
SURFACE WINDS WILL BE OUT OF THE EAST TO NORTHEAST TODAY AT 12 TO
17 KNOTS...WITH OCCASIONAL GUSTS UP TO 25 KTS THIS MORNING...WITH
WINDS GRADUALLY BECOMING MORE NORTHEAST LATE TODAY AND TONIGHT AT
AROUND 10 KTS.
SMITH
&&
.PREV DISCUSSION...
ISSUED 200 AM CST SAT FEB 4 2012
SURFACE LOW WAS CENTERED OVER SOUTHWEST MISSOURI EARLY THIS
MORNING...WHILE ASSOCIATED UPPER LOW WAS STILL BACK OVER NORTH
CENTRAL KANSAS. INITIAL BAND OF RAIN HAD ADVANCED INTO EASTERN
ILLINOIS...WITH AREAS WEST OF I-55 TAPERING DOWN TO DRIZZLE. A
WEDGE OF DRIER AIR WAS SEEN ON WATER VAPOR IMAGERY ACROSS
SOUTHEAST KANSAS...ADVECTING INTO MISSOURI.
INITIAL FORECAST CONCERN REVOLVES AROUND THE EXTENT OF RAINFALL
TODAY AND THIS EVENING. LATER ON...POTENTIAL COOL SNAP LATE IN THE
FORECAST PERIOD IS THE FOCUS.
SHORT TERM...TODAY THROUGH MONDAY...
LATEST HRRR SHOWING THE CURRENT BAND OF RAIN SHOULD BE EXITING THE
EASTERN CWA TOWARD SUNRISE...BUT BAND OF PRECIPITATION IN A
BAROCLINIC ZONE ALONG THE I-80 CORRIDOR FROM IOWA TO INDIANA WILL
EXPAND AND SINK A BIT FURTHER SOUTH. FORECAST SOUNDINGS SHOWING
DRY AIR EXPANDING ABOVE 700 MB AS THE DAY PROGRESSES...TRENDING
THE PRECIPITATION INTO MORE OF A DRIZZLE OR VERY LIGHT RAIN. MAIN
SURFACE LOW SHOULD MAKE STEADY PROGRESS EASTWARD INTO THE OHIO
VALLEY BY EVENING...BUT 00Z MODELS SHOWING THE UPPER LOW LAGGING
BEHIND QUITE A BIT THROUGH SUNDAY AND POTENTIALLY EVEN INTO EARLY
MONDAY. WILL LINGER SOME PRECIPITATION INTO THIS EVENING...BUT
PERSISTENT NORTH/NORTHEAST SURFACE FLOW INTO THE AREA WILL
EVENTUALLY TAKE ITS TOLL AND DRY OUT THE LOWER ATMOSPHERE...THUS
WILL KEEP THE FORECAST DRY FOR SUNDAY AND MONDAY DESPITE THE
UPPER LOW BEING RELATIVELY CLOSE BY.
SOUNDINGS KEEP THE CLOUDS FAIRLY THICK TODAY...SO DID NOT SEE A
REASON TO STRAY FROM THE CONSENSUS OF THE TIGHTLY PACKED NUMERICAL
GUIDANCE. TONIGHT IS A BIT TRICKIER...AS THE SPEED OF THE CLEARING
FROM THE NORTH MAY DROP TEMPERATURES QUICKER THAN EXPECTED. FOR
NOW...WILL GO WITH LOWS BELOW FREEZING OVER MOST AREAS NORTH OF
THE I-72 CORRIDOR...WITH 20S QUITE LIKELY ACROSS THE FAR NORTHERN
CWA. TEMPERATURES SUNDAY AND MONDAY WILL ONCE AGAIN BE SEVERAL
DEGREES ABOVE NORMAL.
LONG TERM...TUESDAY THROUGH FRIDAY...
A PIECE OF LEFTOVER ENERGY FROM THE CURRENT UPPER LOW IN THE
PLAINS WILL GET STRANDED OVER THE CENTRAL ROCKIES THIS WEEKEND...
BEFORE FINALLY MOVING EASTWARD INTO THE CENTRAL U.S. BY MIDWEEK.
SPLIT UPPER FLOW WILL KEEP MOISTURE ADVECTION IN OUR AREA RATHER
MINIMAL...SO WILL ONLY GO WITH SLIGHT CHANCES FOR PRECIPITATION...
PRIMARILY ON WEDNESDAY.
IN THE LONGER RANGE...UPPER PATTERN BEGINS TO SHIFT QUITE A BIT AS
A LOW CUTS OFF OVER BAJA CALIFORNIA. ALL OF THE MEDIUM RANGE
MODELS PLACE OUR AREA IN A NORTHWEST FLOW FOR THE LATTER PART OF
THE WORK WEEK...WITH TEMPERATURES NEAR OR EVEN A BIT BELOW NORMAL
FOR A CHANGE. LOBES OF ARCTIC AIR SHOULD SWING ACROSS THE GREAT
LAKES REGION...WITH OUR AREA RECEIVING GLANCING BLOWS WITH
POTENTIAL FOR A MORE SUBSTANTIAL BLAST OF COLD AIR TOWARD NEXT
WEEKEND.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
958 AM CST SAT FEB 4 2012
.DISCUSSION...
953 AM CST
SENT SOME TWEAKED GRIDS TO UPDATE SHORT TERM TRENDS FOR TODAY.
APPEARS AS THOUGH DEFORMATION BAND WILL REMAIN PARKED OVER ABOUT
THE SOUTHERN 1/3RD OF OUR CWA THROUGH THE DAY. ACARS SOUNDINGS AS
WELL AS 12Z RAOBS FROM ILX AND DVN WOULD SUGGEST THAT THERMALLY WE
ARE HUGGING THE RAIN/WET SNOW LINE WHERE PRECIP IS FALLING.
SUSPECT WE WILL STAY MOSTLY RAIN...THOUGH THE HEAVIER BURSTS OF
PRECIP COULD ALLOW FOR RAIN TO MIX WITH OR EVEN BRIEFLY CHANGE TO
WET SNOW AT TIMES TODAY. HAVE SHARPENED THE POP GRADIENT ACROSS
THE CWA AND MAINTAINED CATEGORICAL POPS INTO THE AFTERNOON OVER
FAR SOUTH. ALSO...PRECIP AND CLOUD COVER SHOULD KEEP TEMPS FROM
GOING MUCH OF ANYWHERE SOUTH AND HAVE LOWERED HIGH TEMPS THERE A
FEW DEGREES...WHILE SOME CLEARING FAR NORTH COULD ALLOW TEMPS TO
REBOUND TO AROUND 40.
UPDATED GRIDS ARE OUT AND ZFP WILL BE FOLLOWING MOMENTARILY.
IZZI
&&
.PREV DISCUSSION...
245 AM CST
MAIN FORECAST CONCERNS THIS MORNING WILL BE DEALING WITH PRECIP
TYPE THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. AREA OF
LOW PRESSURE OVER SOUTHERN MISSOURI WILL CONTINUE TO TREK ENE
TOWARDS THE OHIO RIVER VALLEY TODAY WITH WARM ADVECTION
PRECIPITATION OVERSPREADING AREAS AHEAD OF THE LOW INTO THE
PORTIONS OF NORTHERN ILLINOIS AND NORTHWEST INDIANA. STRONG MID
LEVEL FGEN BAND HAS SET UP THIS MORNING WITH STEADY RAIN
OCCASIONALLY MIXING WITH SNOW FALLING ALONG AND SOUTH OF THE I-88
AND I-80 CORRIDORS. THIS FGEN BAND IS PROGGED TO TRANSLATE EAST
ACROSS NORTHWEST INDIANA TODAY WITH PRECIP GRADUALLY TAPERING FROM
THE NORTH THROUGH THE PERIOD. WHILE MAINLY RAIN HAS FALLEN SO
FAR...HAVE SEEN BRIEF BURSTS OF SNOWFALL REACHING THE SURFACE AND
DUAL-POL IMAGERY DOES INDICATE LOWERING MELTING LEVELS THIS
MORNING...PARTICULARLY ON THE NORTHERN PERIPHERY OF THE PRECIP
SHIELD. THIS SUPPORTS MODEL SOUNDINGS WHICH DO SHOW THE COLUMN
COOLING SLIGHTLY WITH SOME AREAS COOLING ENOUGH FOR A CHANGE OVER
TO SNOW...MAINLY ACROSS NORTHWESTERN INDIANA AND AREAS NORTH OF
THE I-80 CORRIDOR. AM CONCERNED THAT PORTIONS OF PORTER/LAKE/JASPER
COUNTIES IN INDIANA MAY SEE LIGHT ACCUMULATIONS...AND LATEST OB
FROM VPZ ASOS JUST REPORTING CHANGE OVER TO SNOW. GIVEN A FAIRLY
MODEST SLR OF 8-10:1 THERE SHOULD BE SUFFICIENT FORCING STILL FOR
PERHAPS AND INCH OR SO ACCUMULATION ACROSS THESE AREAS BEFORE
PRECIP ENDS OR THE BOUNDARY LAYER WARMS. FOR THE REST OF THE
CWA...EXPECT THE COLUMN TO REMAIN WARM ENOUGH FOR RAIN THROUGH THE
EARLY MORNING HOURS.
NORTHERN STREAM SHORTWAVE TROUGH WILL PHASE WITH UPPER LEVEL
DISTURBANCE ASSOCIATED WITH OUR LOW TO THE SOUTH LATER THIS EVENING
WITH STRONG HEIGHT RISES BUILDING IN BEHIND THE MERGING SYSTEMS.
UPPER LEVEL RIDGING WILL THEN BUILD OVER THE AREA AND SHOULD PROVIDE
A FEW DAYS OF DRY WEATHER WITH ABOVE NORMAL TEMPERATURES CONTINUING.
MONDAY LOOKS TO BE OUR WARMEST DAY AS MID/UPPER LEVEL RIDGE AXIS
MOVES OVERHEAD...WITH SURFACE TEMPERATURES IN THE MID TO UPPER 40S
EXPECTED. MODELS HAVE DIFFICULT TIME HANDLING REX BLOCK OVER THE
WESTERN CONUS...BUT STILL SHOW SOME HINT THAT MAY SEE TRANSIENT
SHORTWAVES IN THE NORTHWEST FLOW BRINGING CHANCES OF PRECIP TO THE
AREA MIDWEEK OR SO...BUT CONFIDENCE VERY LOW FOR ANY GIVEN TIMING
AT THIS POINT. GEFS ENSEMBLE DOES INDICATE THAT THE WEST COAST
RIDGE WILL AMPLIFY MIDWEEK WITH STRONG TROUGHING DEVELOPING
ACROSS THE EASTERN HALF OF THE CONUS. SHOULD THIS PAN OUT...COULD
BE LOOKING AT MORE SEASONABLE TEMPERATURES...POSSIBLY STICKING FOR
A WHILE IF THE PATTERN TAKES TIME TO BREAK DOWN...AND A DEPARTURE
FROM THE GOING WARMTH WE HAVE HAD THUS FAR THIS WINTER.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 15Z...
* GRADUAL IMPROVEMENT TO CIGS. EXPECT BY 18Z CIGS SHUD BE HOVERING
ARND 2KFT AGL...THEN STEADILY LIFT THRU THE AFTN/EVE.
* PSBL LGT PRECIP SOUTH OF ORD/MDW THIS AFTN.
* E-NE WINDS ARND 10KT OCCASIONAL GUST TO 16KT THIS AFTN. THEN LGT
N WINDS OVERNIGHT.
BEACHLER
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE WAS MOVING FROM SOUTHERN MISSOURI TOWARD THE LOWER
OHIO VALLEY THIS MORNING...WITH FAIRLY EXTENSIVE AREA OF MVFR
CEILINGS ACROSS IL/FAR SOUTHERN WI/INDIANA AND SOUTHWEST MI. BAND
OF RAIN/SNOW WHICH HAD DEVELOPED LAST EVENING FROM ROUGHLY KMLI TO
KVYS AND KVPZ HAS WEAKENED AND SHIFTED SOUTH...BUT HAS LEFT IFR
VIS/CIGS IN ITS WAKE AT KMDW AND KGYY. WHILE SOME IMPROVEMENT IS
EXPECTED THIS MORNING WITH LOSS OF PRECIP...FAIRLY STRONG
MID/UPPER LEVEL ASCENT WILL CONTINUE INTO THIS AFTERNOON AS UPPER
LOW OVER THE CENTRAL PLAINS CONTINUES TO MOVE SLOWLY EAST. LOW
LEVEL THERMAL GRADIENT WILL RESULT IN LINGERING FOCUS FOR
ADDITIONAL PRECIPITATION MAINLY SOUTH OF THE TERMINALS AS
GRADUALLY WEAKENING UPPER CIRCULATION CONTINUES TO PRODUCE LIFT.
RECENT HIGH RES MODEL RUNS SUCH AS HRRR SUGGEST RAIN MAY REDEVELOP
AS FAR NORTH AS THE I-80 CORRIDOR AND MAY AFFECT KGYY FOR A TIME
AND PERHAPS EVEN COME CLOSE TO KMDW EARLY THIS AFTERNOON. THIS
WOULD LIKELY TEND TO KEEP CEILING IMPROVEMENT SLOWER ACROSS THE
SOUTH METRO TERMINALS...WITH BETTER DRY LOW LEVEL ADVECTION NOT
REALLY DEVELOPING UNTIL LATE AFTERNOON AS THE SURFACE LOW PRESSURE
CENTER SCOOTS BY TO THE SOUTH AND ALLOWS EASTERLY WINDS TO BECOME
MORE NORTHERLY. FARTHER NORTH AT KORD/KDPA/KRFD...WILL LIKELY SEE
AN EARLIER BUT STILL GRADUAL IMPROVEMENT TO CIGS THROUGH MVFR
RANGE. LOW CLOUDS SHOULD EVENTUALLY SCATTER FROM THE
NORTH/NORTHWEST LATE TODAY...WITH SKIES CLEARING THIS EVENING.
WINDS WILL GENERALLY RANGE IN THE 10-15 KT RANGE THROUGH THE DAY
WITH A MORE EASTERLY COMPONENT THROUGH EARLY AFTERNOON...SAY
080-060 DEGREES. WINDS SHOULD GRADUALLY BACK MORE NORTHEAST THIS
AFTERNOON...AND THEN NORTH WITH SPEEDS FALLING BELOW 10 KTS THIS
EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 15Z...
* MEDIUM-HIGH CONFIDENCE IN CIGS IMPROVING BY THIS AFTN.
* LOW CONFIDENCE IN PSBL FOG DEVELOPMENT OVERNIGHT.
* HIGH CONFIDENCE IN WIND FORECAST.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
RATZER
&&
.MARINE...
256 AM CST
A HIGH PRESSURE RIDGE EXTENDS ACROSS CENTRAL AND NORTHERN LAKE
MICHIGAN THIS MORNING...WHILE AN AREA OF LOW PRESSURE WAS OVER
SOUTHERN MISSOURI. WINDS WERE GENERALLY LESS THAN 10 KTS ACROSS THE
NORTHERN PORTIONS OF LAKE MICHIGAN NEAR THE RIDGE AXIS...WHILE THE
SOUTHERN PORTION OF THE LAKE SEES EAST TO NORTHEAST WINDS AROUND 15
KTS WHERE THE GRADIENT WILL BE A LITTLE STRONGER CLOSER TO THE
MISSOURI/LOWER OHIO VALLEY LOW. THIS LOW WILL CONTINUE TO MOVE EAST
ACROSS THE LOWER OHIO VALLEY AND SOUTHERN APPALACHIANS THROUGH THIS
EVENING BEFORE MOVING INTO THE MID-ATLANTIC REGION EARLY SUNDAY.
MEANWHILE THE RIDGE ACROSS THE WESTERN LAKES WILL WEAKEN
TODAY...WHILE A WEAKER AREA OF LOW PRESSURE MOVES NORTHEAST OF THE
LAKES ACROSS EASTERN ONTARIO. DEEPER LOW PRESSURE WILL DEVELOP NORTH
OF THE LAKES ACROSS HUDSON BAY ON SUNDAY...AND WILL MOVE SOUTHEAST
INTO CENTRAL QUEBEC ON MONDAY WITH A COLD FRONT TRAILING ACROSS THE
WESTERN LAKES. WESTERLY WINDS WILL INCREASE INTO THE 15-25 KT RANGE
AS THE GRADIENT TIGHTENS IN ASSOCIATION WITH THIS LOW AND
APPROACHING FRONTAL TROUGH...WITH PERHAPS THE STRONGEST WINDS IN THE
20-25 KT RANGE ON THE NORTHERN END OF THE LAKE MONDAY MORNING.
COLDER AIR WILL SPREAD IN BEHIND THE FRONT AS STRONG HIGH PRESSURE
BUILDS SOUTHEAST OUT OF CENTRAL CANADA MONDAY NIGHT INTO
TUESDAY...BUT THE HIGH WILL WEAKEN AS IT REACHES THE UPPER MIDWEST
AND GREAT LAKES REGION BY MID-WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
919 AM CST SAT FEB 4 2012
.DISCUSSION...
245 AM CST
MAIN FORECAST CONCERNS THIS MORNING WILL BE DEALING WITH PRECIP
TYPE THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. AREA OF
LOW PRESSURE OVER SOUTHERN MISSOURI WILL CONTINUE TO TREK ENE
TOWARDS THE OHIO RIVER VALLEY TODAY WITH WARM ADVECTION
PRECIPITATION OVERSPREADING AREAS AHEAD OF THE LOW INTO THE
PORTIONS OF NORTHERN ILLINOIS AND NORTHWEST INDIANA. STRONG MID
LEVEL FGEN BAND HAS SET UP THIS MORNING WITH STEADY RAIN
OCCASIONALLY MIXING WITH SNOW FALLING ALONG AND SOUTH OF THE I-88
AND I-80 CORRIDORS. THIS FGEN BAND IS PROGGED TO TRANSLATE EAST
ACROSS NORTHWEST INDIANA TODAY WITH PRECIP GRADUALLY TAPERING FROM
THE NORTH THROUGH THE PERIOD. WHILE MAINLY RAIN HAS FALLEN SO
FAR...HAVE SEEN BRIEF BURSTS OF SNOWFALL REACHING THE SURFACE AND
DUAL-POL IMAGERY DOES INDICATE LOWERING MELTING LEVELS THIS
MORNING...PARTICULARLY ON THE NORTHERN PERIPHERY OF THE PRECIP
SHIELD. THIS SUPPORTS MODEL SOUNDINGS WHICH DO SHOW THE COLUMN
COOLING SLIGHTLY WITH SOME AREAS COOLING ENOUGH FOR A CHANGE OVER
TO SNOW...MAINLY ACROSS NORTHWESTERN INDIANA AND AREAS NORTH OF
THE I-80 CORRIDOR. AM CONCERNED THAT PORTIONS OF PORTER/LAKE/JASPER
COUNTIES IN INDIANA MAY SEE LIGHT ACCUMULATIONS...AND LATEST OB
FROM VPZ ASOS JUST REPORTING CHANGE OVER TO SNOW. GIVEN A FAIRLY
MODEST SLR OF 8-10:1 THERE SHOULD BE SUFFICIENT FORCING STILL FOR
PERHAPS AND INCH OR SO ACCUMULATION ACROSS THESE AREAS BEFORE
PRECIP ENDS OR THE BOUNDARY LAYER WARMS. FOR THE REST OF THE
CWA...EXPECT THE COLUMN TO REMAIN WARM ENOUGH FOR RAIN THROUGH THE
EARLY MORNING HOURS.
NORTHERN STREAM SHORTWAVE TROUGH WILL PHASE WITH UPPER LEVEL
DISTURBANCE ASSOCIATED WITH OUR LOW TO THE SOUTH LATER THIS EVENING
WITH STRONG HEIGHT RISES BUILDING IN BEHIND THE MERGING SYSTEMS.
UPPER LEVEL RIDGING WILL THEN BUILD OVER THE AREA AND SHOULD PROVIDE
A FEW DAYS OF DRY WEATHER WITH ABOVE NORMAL TEMPERATURES CONTINUING.
MONDAY LOOKS TO BE OUR WARMEST DAY AS MID/UPPER LEVEL RIDGE AXIS
MOVES OVERHEAD...WITH SURFACE TEMPERATURES IN THE MID TO UPPER 40S
EXPECTED. MODELS HAVE DIFFICULT TIME HANDLING REX BLOCK OVER THE
WESTERN CONUS...BUT STILL SHOW SOME HINT THAT MAY SEE TRANSIENT
SHORTWAVES IN THE NORTHWEST FLOW BRINGING CHANCES OF PRECIP TO THE
AREA MIDWEEK OR SO...BUT CONFIDENCE VERY LOW FOR ANY GIVEN TIMING
AT THIS POINT. GEFS ENSEMBLE DOES INDICATE THAT THE WEST COAST
RIDGE WILL AMPLIFY MIDWEEK WITH STRONG TROUGHING DEVELOPING
ACROSS THE EASTERN HALF OF THE CONUS. SHOULD THIS PAN OUT...COULD
BE LOOKING AT MORE SEASONABLE TEMPERATURES...POSSIBLY STICKING FOR
A WHILE IF THE PATTERN TAKES TIME TO BREAK DOWN...AND A DEPARTURE
FROM THE GOING WARMTH WE HAVE HAD THUS FAR THIS WINTER.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 15Z...
* GRADUAL IMPROVEMENT TO CIGS. EXPECT BY 18Z CIGS SHUD BE HOVERING
ARND 2KFT AGL...THEN STEADILY LIFT THRU THE AFTN/EVE.
* PSBL LGT PRECIP SOUTH OF ORD/MDW THIS AFTN.
* E-NE WINDS ARND 10KT OCCASIONAL GUST TO 16KT THIS AFTN. THEN LGT
N WINDS OVERNIGHT.
BEACHLER
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE WAS MOVING FROM SOUTHERN MISSOURI TOWARD THE LOWER
OHIO VALLEY THIS MORNING...WITH FAIRLY EXTENSIVE AREA OF MVFR
CEILINGS ACROSS IL/FAR SOUTHERN WI/INDIANA AND SOUTHWEST MI. BAND
OF RAIN/SNOW WHICH HAD DEVELOPED LAST EVENING FROM ROUGHLY KMLI TO
KVYS AND KVPZ HAS WEAKENED AND SHIFTED SOUTH...BUT HAS LEFT IFR
VIS/CIGS IN ITS WAKE AT KMDW AND KGYY. WHILE SOME IMPROVEMENT IS
EXPECTED THIS MORNING WITH LOSS OF PRECIP...FAIRLY STRONG
MID/UPPER LEVEL ASCENT WILL CONTINUE INTO THIS AFTERNOON AS UPPER
LOW OVER THE CENTRAL PLAINS CONTINUES TO MOVE SLOWLY EAST. LOW
LEVEL THERMAL GRADIENT WILL RESULT IN LINGERING FOCUS FOR
ADDITIONAL PRECIPITATION MAINLY SOUTH OF THE TERMINALS AS
GRADUALLY WEAKENING UPPER CIRCULATION CONTINUES TO PRODUCE LIFT.
RECENT HIGH RES MODEL RUNS SUCH AS HRRR SUGGEST RAIN MAY REDEVELOP
AS FAR NORTH AS THE I-80 CORRIDOR AND MAY AFFECT KGYY FOR A TIME
AND PERHAPS EVEN COME CLOSE TO KMDW EARLY THIS AFTERNOON. THIS
WOULD LIKELY TEND TO KEEP CEILING IMPROVEMENT SLOWER ACROSS THE
SOUTH METRO TERMINALS...WITH BETTER DRY LOW LEVEL ADVECTION NOT
REALLY DEVELOPING UNTIL LATE AFTERNOON AS THE SURFACE LOW PRESSURE
CENTER SCOOTS BY TO THE SOUTH AND ALLOWS EASTERLY WINDS TO BECOME
MORE NORTHERLY. FARTHER NORTH AT KORD/KDPA/KRFD...WILL LIKELY SEE
AN EARLIER BUT STILL GRADUAL IMPROVEMENT TO CIGS THROUGH MVFR
RANGE. LOW CLOUDS SHOULD EVENTUALLY SCATTER FROM THE
NORTH/NORTHWEST LATE TODAY...WITH SKIES CLEARING THIS EVENING.
WINDS WILL GENERALLY RANGE IN THE 10-15 KT RANGE THROUGH THE DAY
WITH A MORE EASTERLY COMPONENT THROUGH EARLY AFTERNOON...SAY
080-060 DEGREES. WINDS SHOULD GRADUALLY BACK MORE NORTHEAST THIS
AFTERNOON...AND THEN NORTH WITH SPEEDS FALLING BELOW 10 KTS THIS
EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 15Z...
* MEDIUM-HIGH CONFIDENCE IN CIGS IMPROVING BY THIS AFTN.
* LOW CONFIDENCE IN PSBL FOG DEVELOPMENT OVERNIGHT.
* HIGH CONFIDENCE IN WIND FORECAST.
BEACHLER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
RATZER
&&
.MARINE...
256 AM CST
A HIGH PRESSURE RIDGE EXTENDS ACROSS CENTRAL AND NORTHERN LAKE
MICHIGAN THIS MORNING...WHILE AN AREA OF LOW PRESSURE WAS OVER
SOUTHERN MISSOURI. WINDS WERE GENERALLY LESS THAN 10 KTS ACROSS THE
NORTHERN PORTIONS OF LAKE MICHIGAN NEAR THE RIDGE AXIS...WHILE THE
SOUTHERN PORTION OF THE LAKE SEES EAST TO NORTHEAST WINDS AROUND 15
KTS WHERE THE GRADIENT WILL BE A LITTLE STRONGER CLOSER TO THE
MISSOURI/LOWER OHIO VALLEY LOW. THIS LOW WILL CONTINUE TO MOVE EAST
ACROSS THE LOWER OHIO VALLEY AND SOUTHERN APPALACHIANS THROUGH THIS
EVENING BEFORE MOVING INTO THE MID-ATLANTIC REGION EARLY SUNDAY.
MEANWHILE THE RIDGE ACROSS THE WESTERN LAKES WILL WEAKEN
TODAY...WHILE A WEAKER AREA OF LOW PRESSURE MOVES NORTHEAST OF THE
LAKES ACROSS EASTERN ONTARIO. DEEPER LOW PRESSURE WILL DEVELOP NORTH
OF THE LAKES ACROSS HUDSON BAY ON SUNDAY...AND WILL MOVE SOUTHEAST
INTO CENTRAL QUEBEC ON MONDAY WITH A COLD FRONT TRAILING ACROSS THE
WESTERN LAKES. WESTERLY WINDS WILL INCREASE INTO THE 15-25 KT RANGE
AS THE GRADIENT TIGHTENS IN ASSOCIATION WITH THIS LOW AND
APPROACHING FRONTAL TROUGH...WITH PERHAPS THE STRONGEST WINDS IN THE
20-25 KT RANGE ON THE NORTHERN END OF THE LAKE MONDAY MORNING.
COLDER AIR WILL SPREAD IN BEHIND THE FRONT AS STRONG HIGH PRESSURE
BUILDS SOUTHEAST OUT OF CENTRAL CANADA MONDAY NIGHT INTO
TUESDAY...BUT THE HIGH WILL WEAKEN AS IT REACHES THE UPPER MIDWEST
AND GREAT LAKES REGION BY MID-WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
610 AM CST SAT FEB 4 2012
.DISCUSSION...
245 AM CST
MAIN FORECAST CONCERNS THIS MORNING WILL BE DEALING WITH PRECIP
TYPE THROUGH THE REMAINDER OF THE EARLY MORNING HOURS. AREA OF
LOW PRESSURE OVER SOUTHERN MISSOURI WILL CONTINUE TO TREK ENE
TOWARDS THE OHIO RIVER VALLEY TODAY WITH WARM ADVECTION
PRECIPITATION OVERSPREADING AREAS AHEAD OF THE LOW INTO THE
PORTIONS OF NORTHERN ILLINOIS AND NORTHWEST INDIANA. STRONG MID
LEVEL FGEN BAND HAS SET UP THIS MORNING WITH STEADY RAIN
OCCASIONALLY MIXING WITH SNOW FALLING ALONG AND SOUTH OF THE I-88
AND I-80 CORRIDORS. THIS FGEN BAND IS PROGGED TO TRANSLATE EAST
ACROSS NORTHWEST INDIANA TODAY WITH PRECIP GRADUALLY TAPERING FROM
THE NORTH THROUGH THE PERIOD. WHILE MAINLY RAIN HAS FALLEN SO
FAR...HAVE SEEN BRIEF BURSTS OF SNOWFALL REACHING THE SURFACE AND
DUAL-POL IMAGERY DOES INDICATE LOWERING MELTING LEVELS THIS
MORNING...PARTICULARLY ON THE NORTHERN PERIPHERY OF THE PRECIP
SHIELD. THIS SUPPORTS MODEL SOUNDINGS WHICH DO SHOW THE COLUMN
COOLING SLIGHTLY WITH SOME AREAS COOLING ENOUGH FOR A CHANGE OVER
TO SNOW...MAINLY ACROSS NORTHWESTERN INDIANA AND AREAS NORTH OF
THE I-80 CORRIDOR. AM CONCERNED THAT PORTIONS OF PORTER/LAKE/JASPER
COUNTIES IN INDIANA MAY SEE LIGHT ACCUMULATIONS...AND LATEST OB
FROM VPZ ASOS JUST REPORTING CHANGE OVER TO SNOW. GIVEN A FAIRLY
MODEST SLR OF 8-10:1 THERE SHOULD BE SUFFICIENT FORCING STILL FOR
PERHAPS AND INCH OR SO ACCUMULATION ACROSS THESE AREAS BEFORE
PRECIP ENDS OR THE BOUNDARY LAYER WARMS. FOR THE REST OF THE
CWA...EXPECT THE COLUMN TO REMAIN WARM ENOUGH FOR RAIN THROUGH THE
EARLY MORNING HOURS.
NORTHERN STREAM SHORTWAVE TROUGH WILL PHASE WITH UPPER LEVEL
DISTURBANCE ASSOCIATED WITH OUR LOW TO THE SOUTH LATER THIS EVENING
WITH STRONG HEIGHT RISES BUILDING IN BEHIND THE MERGING SYSTEMS.
UPPER LEVEL RIDGING WILL THEN BUILD OVER THE AREA AND SHOULD PROVIDE
A FEW DAYS OF DRY WEATHER WITH ABOVE NORMAL TEMPERATURES CONTINUING.
MONDAY LOOKS TO BE OUR WARMEST DAY AS MID/UPPER LEVEL RIDGE AXIS
MOVES OVERHEAD...WITH SURFACE TEMPERATURES IN THE MID TO UPPER 40S
EXPECTED. MODELS HAVE DIFFICULT TIME HANDLING REX BLOCK OVER THE
WESTERN CONUS...BUT STILL SHOW SOME HINT THAT MAY SEE TRANSIENT
SHORTWAVES IN THE NORTHWEST FLOW BRINGING CHANCES OF PRECIP TO THE
AREA MIDWEEK OR SO...BUT CONFIDENCE VERY LOW FOR ANY GIVEN TIMING
AT THIS POINT. GEFS ENSEMBLE DOES INDICATE THAT THE WEST COAST
RIDGE WILL AMPLIFY MIDWEEK WITH STRONG TROUGHING DEVELOPING
ACROSS THE EASTERN HALF OF THE CONUS. SHOULD THIS PAN OUT...COULD
BE LOOKING AT MORE SEASONABLE TEMPERATURES...POSSIBLY STICKING FOR
A WHILE IF THE PATTERN TAKES TIME TO BREAK DOWN...AND A DEPARTURE
FROM THE GOING WARMTH WE HAVE HAD THUS FAR THIS WINTER.
BMD
&&
.AVIATION...
//ORD AND MDW CONCERNS...UPDATED 12Z...
* MVFR/IFR CIGS AND VIS WITH LOWER CONDITIONS AT KMDW THIS MORNING.
* SLOW IMPROVING TREND EXPECTED IN CEILING HEIGHTS.
* POTENTIAL FOR ADDITIONAL LIGHT PRECIP SOUTH OF KORD/KMDW THROUGH
MID-AFTERNOON.
* EAST-NORTHEAST WINDS 10-15 KTS BECOMING NORTH-NORTHEAST LATER
THIS AFTERNOON...THEN LIGHT NORTH TONIGHT.
RATZER
//DISCUSSION...UPDATED 12Z...
LOW PRESSURE WAS MOVING FROM SOUTHERN MISSOURI TOWARD THE LOWER
OHIO VALLEY THIS MORNING...WITH FAIRLY EXTENSIVE AREA OF MVFR
CEILINGS ACROSS IL/FAR SOUTHERN WI/INDIANA AND SOUTHWEST MI. BAND
OF RAIN/SNOW WHICH HAD DEVELOPED LAST EVENING FROM ROUGHLY KMLI TO
KVYS AND KVPZ HAS WEAKENED AND SHIFTED SOUTH...BUT HAS LEFT IFR
VIS/CIGS IN ITS WAKE AT KMDW AND KGYY. WHILE SOME IMPROVEMENT IS
EXPECTED THIS MORNING WITH LOSS OF PRECIP...FAIRLY STRONG
MID/UPPER LEVEL ASCENT WILL CONTINUE INTO THIS AFTERNOON AS UPPER
LOW OVER THE CENTRAL PLAINS CONTINUES TO MOVE SLOWLY EAST. LOW
LEVEL THERMAL GRADIENT WILL RESULT IN LINGERING FOCUS FOR
ADDITIONAL PRECIPITATION MAINLY SOUTH OF THE TERMINALS AS
GRADUALLY WEAKENING UPPER CIRCULATION CONTINUES TO PRODUCE LIFT.
RECENT HIGH RES MODEL RUNS SUCH AS HRRR SUGGEST RAIN MAY REDEVELOP
AS FAR NORTH AS THE I-80 CORRIDOR AND MAY AFFECT KGYY FOR A TIME
AND PERHAPS EVEN COME CLOSE TO KMDW EARLY THIS AFTERNOON. THIS
WOULD LIKELY TEND TO KEEP CEILING IMPROVEMENT SLOWER ACROSS THE
SOUTH METRO TERMINALS...WITH BETTER DRY LOW LEVEL ADVECTION NOT
REALLY DEVELOPING UNTIL LATE AFTERNOON AS THE SURFACE LOW PRESSURE
CENTER SCOOTS BY TO THE SOUTH AND ALLOWS EASTERLY WINDS TO BECOME
MORE NORTHERLY. FARTHER NORTH AT KORD/KDPA/KRFD...WILL LIKELY SEE
AN EARLIER BUT STILL GRADUAL IMPROVEMENT TO CIGS THROUGH MVFR
RANGE. LOW CLOUDS SHOULD EVENTUALLY SCATTER FROM THE
NORTH/NORTHWEST LATE TODAY...WITH SKIES CLEARING THIS EVENING.
WINDS WILL GENERALLY RANGE IN THE 10-15 KT RANGE THROUGH THE DAY
WITH A MORE EASTERLY COMPONENT THROUGH EARLY AFTERNOON...SAY
080-060 DEGREES. WINDS SHOULD GRADUALLY BACK MORE NORTHEAST THIS
AFTERNOON...AND THEN NORTH WITH SPEEDS FALLING BELOW 10 KTS THIS
EVENING.
RATZER
//ORD AND MDW CONFIDENCE...UPDATED 12Z...
* MEDIUM-HIGH CONFIDENCE IN OVERALL TREND OF IMPROVING CIG/VIS
CONDITIONS THROUGH THIS EVENING...THOUGH LOWER CONFIDENCE IN
DETAILED TIMING.
* MEDIUM-LOW CONFIDENCE IN PRECIPITATION TIMING/LOCATION WITH
RESPECT TO KMDW THIS AFTERNOON.
* HIGH CONFIDENCE IN WIND TRENDS.
RATZER
//OUTLOOK FOR ORD/MDW FOR 00Z MONDAY-12Z SATURDAY...UPDATED 12Z...
SUNDAY NIGHT...VFR.
MONDAY...VFR.
TUESDAY...VFR.
WEDNESDAY...VFR.
THURSDAY...VFR.
FRIDAY...VFR.
RATZER
&&
.MARINE...
256 AM CST
A HIGH PRESSURE RIDGE EXTENDS ACROSS CENTRAL AND NORTHERN LAKE
MICHIGAN THIS MORNING...WHILE AN AREA OF LOW PRESSURE WAS OVER
SOUTHERN MISSOURI. WINDS WERE GENERALLY LESS THAN 10 KTS ACROSS THE
NORTHERN PORTIONS OF LAKE MICHIGAN NEAR THE RIDGE AXIS...WHILE THE
SOUTHERN PORTION OF THE LAKE SEES EAST TO NORTHEAST WINDS AROUND 15
KTS WHERE THE GRADIENT WILL BE A LITTLE STRONGER CLOSER TO THE
MISSOURI/LOWER OHIO VALLEY LOW. THIS LOW WILL CONTINUE TO MOVE EAST
ACROSS THE LOWER OHIO VALLEY AND SOUTHERN APPALACHIANS THROUGH THIS
EVENING BEFORE MOVING INTO THE MID-ATLANTIC REGION EARLY SUNDAY.
MEANWHILE THE RIDGE ACROSS THE WESTERN LAKES WILL WEAKEN
TODAY...WHILE A WEAKER AREA OF LOW PRESSURE MOVES NORTHEAST OF THE
LAKES ACROSS EASTERN ONTARIO. DEEPER LOW PRESSURE WILL DEVELOP NORTH
OF THE LAKES ACROSS HUDSON BAY ON SUNDAY...AND WILL MOVE SOUTHEAST
INTO CENTRAL QUEBEC ON MONDAY WITH A COLD FRONT TRAILING ACROSS THE
WESTERN LAKES. WESTERLY WINDS WILL INCREASE INTO THE 15-25 KT RANGE
AS THE GRADIENT TIGHTENS IN ASSOCIATION WITH THIS LOW AND
APPROACHING FRONTAL TROUGH...WITH PERHAPS THE STRONGEST WINDS IN THE
20-25 KT RANGE ON THE NORTHERN END OF THE LAKE MONDAY MORNING.
COLDER AIR WILL SPREAD IN BEHIND THE FRONT AS STRONG HIGH PRESSURE
BUILDS SOUTHEAST OUT OF CENTRAL CANADA MONDAY NIGHT INTO
TUESDAY...BUT THE HIGH WILL WEAKEN AS IT REACHES THE UPPER MIDWEST
AND GREAT LAKES REGION BY MID-WEEK.
RATZER
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
528 AM CST SAT FEB 4 2012
.DISCUSSION...
ISSUED 200 AM CST SAT FEB 4 2012
SURFACE LOW WAS CENTERED OVER SOUTHWEST MISSOURI EARLY THIS
MORNING...WHILE ASSOCIATED UPPER LOW WAS STILL BACK OVER NORTH
CENTRAL KANSAS. INITIAL BAND OF RAIN HAD ADVANCED INTO EASTERN
ILLINOIS...WITH AREAS WEST OF I-55 TAPERING DOWN TO DRIZZLE. A
WEDGE OF DRIER AIR WAS SEEN ON WATER VAPOR IMAGERY ACROSS
SOUTHEAST KANSAS...ADVECTING INTO MISSOURI.
INITIAL FORECAST CONCERN REVOLVES AROUND THE EXTENT OF RAINFALL
TODAY AND THIS EVENING. LATER ON...POTENTIAL COOL SNAP LATE IN THE
FORECAST PERIOD IS THE FOCUS.
SHORT TERM...TODAY THROUGH MONDAY...
LATEST HRRR SHOWING THE CURRENT BAND OF RAIN SHOULD BE EXITING THE
EASTERN CWA TOWARD SUNRISE...BUT BAND OF PRECIPITATION IN A
BAROCLINIC ZONE ALONG THE I-80 CORRIDOR FROM IOWA TO INDIANA WILL
EXPAND AND SINK A BIT FURTHER SOUTH. FORECAST SOUNDINGS SHOWING
DRY AIR EXPANDING ABOVE 700 MB AS THE DAY PROGRESSES...TRENDING
THE PRECIPITATION INTO MORE OF A DRIZZLE OR VERY LIGHT RAIN. MAIN
SURFACE LOW SHOULD MAKE STEADY PROGRESS EASTWARD INTO THE OHIO
VALLEY BY EVENING...BUT 00Z MODELS SHOWING THE UPPER LOW LAGGING
BEHIND QUITE A BIT THROUGH SUNDAY AND POTENTIALLY EVEN INTO EARLY
MONDAY. WILL LINGER SOME PRECIPITATION INTO THIS EVENING...BUT
PERSISTENT NORTH/NORTHEAST SURFACE FLOW INTO THE AREA WILL
EVENTUALLY TAKE ITS TOLL AND DRY OUT THE LOWER ATMOSPHERE...THUS
WILL KEEP THE FORECAST DRY FOR SUNDAY AND MONDAY DESPITE THE
UPPER LOW BEING RELATIVELY CLOSE BY.
SOUNDINGS KEEP THE CLOUDS FAIRLY THICK TODAY...SO DID NOT SEE A
REASON TO STRAY FROM THE CONSENSUS OF THE TIGHTLY PACKED NUMERICAL
GUIDANCE. TONIGHT IS A BIT TRICKIER...AS THE SPEED OF THE CLEARING
FROM THE NORTH MAY DROP TEMPERATURES QUICKER THAN EXPECTED. FOR
NOW...WILL GO WITH LOWS BELOW FREEZING OVER MOST AREAS NORTH OF
THE I-72 CORRIDOR...WITH 20S QUITE LIKELY ACROSS THE FAR NORTHERN
CWA. TEMPERATURES SUNDAY AND MONDAY WILL ONCE AGAIN BE SEVERAL
DEGREES ABOVE NORMAL.
LONG TERM...TUESDAY THROUGH FRIDAY...
A PIECE OF LEFTOVER ENERGY FROM THE CURRENT UPPER LOW IN THE
PLAINS WILL GET STRANDED OVER THE CENTRAL ROCKIES THIS WEEKEND...
BEFORE FINALLY MOVING EASTWARD INTO THE CENTRAL U.S. BY MIDWEEK.
SPLIT UPPER FLOW WILL KEEP MOISTURE ADVECTION IN OUR AREA RATHER
MINIMAL...SO WILL ONLY GO WITH SLIGHT CHANCES FOR PRECIPITATION...
PRIMARILY ON WEDNESDAY.
IN THE LONGER RANGE...UPPER PATTERN BEGINS TO SHIFT QUITE A BIT AS
A LOW CUTS OFF OVER BAJA CALIFORNIA. ALL OF THE MEDIUM RANGE
MODELS PLACE OUR AREA IN A NORTHWEST FLOW FOR THE LATTER PART OF
THE WORK WEEK...WITH TEMPERATURES NEAR OR EVEN A BIT BELOW NORMAL
FOR A CHANGE. LOBES OF ARCTIC AIR SHOULD SWING ACROSS THE GREAT
LAKES REGION...WITH OUR AREA RECEIVING GLANCING BLOWS WITH
POTENTIAL FOR A MORE SUBSTANTIAL BLAST OF COLD AIR TOWARD NEXT
WEEKEND.
GEELHART
&&
.AVIATION...
ISSUED 515 AM CST SAT FEB 4 2012
IFR TO LIFR CONDITIONS ARE EXPECTED INTO EARLY TONIGHT AS A STORM
SYSTEM SLOWLY PASSES TO OUR SOUTH TODAY. RAIN/DRIZZLE ALONG WITH
THE LOW CIGS WILL BE THE STORY ACRS THE FORECAST AREA TODAY INTO
EARLY TONIGHT...BEFORE DRIER AIR FILTERS SOUTH INTO CENTRAL IL
BRINGING VFR CONDITIONS TO THE AREA AFTR 06Z. CIGS WILL RANGE
FROM AS LOW AS AROUND 300 FEET...ESPECIALLY AT KBMI...TO 700 FEET
AT MOST OF THE OTHER TAF LOCATIONS. OCCASIONALLY WE MAY SEE THE
CIGS GO ABOVE 1000 FEET FOR A BRIEF TIME BUT FOR THE MOST PART...
WHAT WE ARE SEEING ON SATELLITE AND WITH SFC OBS TO OUR WEST AND
SOUTHWEST DOESN`T LEND MUCH HOPE FOR ANYTHING PROLONGED ABOVE
1000 FEET TODAY.
SURFACE WINDS WILL BE OUT OF THE EAST TO NORTHEAST TODAY AT 12 TO
17 KNOTS...WITH OCCASIONAL GUSTS UP TO 25 KTS THIS MORNING...WITH
WINDS GRADUALLY BECOMING MORE NORTHEAST LATE TODAY AND TONIGHT AT
AROUND 10 KTS.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
200 AM CST SAT FEB 4 2012
.DISCUSSION...
ISSUED 200 AM CST SAT FEB 4 2012
SURFACE LOW WAS CENTERED OVER SOUTHWEST MISSOURI EARLY THIS
MORNING...WHILE ASSOCIATED UPPER LOW WAS STILL BACK OVER NORTH
CENTRAL KANSAS. INITIAL BAND OF RAIN HAD ADVANCED INTO EASTERN
ILLINOIS...WITH AREAS WEST OF I-55 TAPERING DOWN TO DRIZZLE. A
WEDGE OF DRIER AIR WAS SEEN ON WATER VAPOR IMAGERY ACROSS
SOUTHEAST KANSAS...ADVECTING INTO MISSOURI.
INITIAL FORECAST CONCERN REVOLVES AROUND THE EXTENT OF RAINFALL
TODAY AND THIS EVENING. LATER ON...POTENTIAL COOL SNAP LATE IN THE
FORECAST PERIOD IS THE FOCUS.
SHORT TERM...TODAY THROUGH MONDAY...
LATEST HRRR SHOWING THE CURRENT BAND OF RAIN SHOULD BE EXITING THE
EASTERN CWA TOWARD SUNRISE...BUT BAND OF PRECIPITATION IN A
BAROCLINIC ZONE ALONG THE I-80 CORRIDOR FROM IOWA TO INDIANA WILL
EXPAND AND SINK A BIT FURTHER SOUTH. FORECAST SOUNDINGS SHOWING
DRY AIR EXPANDING ABOVE 700 MB AS THE DAY PROGRESSES...TRENDING
THE PRECIPITATION INTO MORE OF A DRIZZLE OR VERY LIGHT RAIN. MAIN
SURFACE LOW SHOULD MAKE STEADY PROGRESS EASTWARD INTO THE OHIO
VALLEY BY EVENING...BUT 00Z MODELS SHOWING THE UPPER LOW LAGGING
BEHIND QUITE A BIT THROUGH SUNDAY AND POTENTIALLY EVEN INTO EARLY
MONDAY. WILL LINGER SOME PRECIPITATION INTO THIS EVENING...BUT
PERSISTENT NORTH/NORTHEAST SURFACE FLOW INTO THE AREA WILL
EVENTUALLY TAKE ITS TOLL AND DRY OUT THE LOWER ATMOSPHERE...THUS
WILL KEEP THE FORECAST DRY FOR SUNDAY AND MONDAY DESPITE THE
UPPER LOW BEING RELATIVELY CLOSE BY.
SOUNDINGS KEEP THE CLOUDS FAIRLY THICK TODAY...SO DID NOT SEE A
REASON TO STRAY FROM THE CONSENSUS OF THE TIGHTLY PACKED NUMERICAL
GUIDANCE. TONIGHT IS A BIT TRICKIER...AS THE SPEED OF THE CLEARING
FROM THE NORTH MAY DROP TEMPERATURES QUICKER THAN EXPECTED. FOR
NOW...WILL GO WITH LOWS BELOW FREEZING OVER MOST AREAS NORTH OF
THE I-72 CORRIDOR...WITH 20S QUITE LIKELY ACROSS THE FAR NORTHERN
CWA. TEMPERATURES SUNDAY AND MONDAY WILL ONCE AGAIN BE SEVERAL
DEGREES ABOVE NORMAL.
LONG TERM...TUESDAY THROUGH FRIDAY...
A PIECE OF LEFTOVER ENERGY FROM THE CURRENT UPPER LOW IN THE
PLAINS WILL GET STRANDED OVER THE CENTRAL ROCKIES THIS WEEKEND...
BEFORE FINALLY MOVING EASTWARD INTO THE CENTRAL U.S. BY MIDWEEK.
SPLIT UPPER FLOW WILL KEEP MOISTURE ADVECTION IN OUR AREA RATHER
MINIMAL...SO WILL ONLY GO WITH SLIGHT CHANCES FOR PRECIPITATION...
PRIMARILY ON WEDNESDAY.
IN THE LONGER RANGE...UPPER PATTERN BEGINS TO SHIFT QUITE A BIT AS
A LOW CUTS OFF OVER BAJA CALIFORNIA. ALL OF THE MEDIUM RANGE
MODELS PLACE OUR AREA IN A NORTHWEST FLOW FOR THE LATTER PART OF
THE WORK WEEK...WITH TEMPERATURES NEAR OR EVEN A BIT BELOW NORMAL
FOR A CHANGE. LOBES OF ARCTIC AIR SHOULD SWING ACROSS THE GREAT
LAKES REGION...WITH OUR AREA RECEIVING GLANCING BLOWS WITH
POTENTIAL FOR A MORE SUBSTANTIAL BLAST OF COLD AIR TOWARD NEXT
WEEKEND.
GEELHART
&&
.AVIATION...
ISSUED 1148 PM CST FRI FEB 3 2012
IFR AND MVFR CONDITIONS WILL CONTINUE OVERNIGHT AS THE RAIN
CONTINUES ACROSS THE AREA. RADAR LOOPS INDICATE THAT PCPN IS
WANING AND THIS SHOULD LEAD TO PCPN BECOMING MORE DRIZZLE
OVERNIGHT. VIS SHOULD REMAIN AROUND 2-3SM AS WELL. CIGS NOT
FALLING AS EXPECTED BUT DO BELIEVE THAT THEY WILL FALL TO BELOW
2KFT BY MORNING. BMI ALREADY BELOW 1KFT BUT DO NOT THINK THIS WILL
ONLY BE FOR NEXT 3 HRS...WITH IMPROVEMENT TIL MORNING. MODELS
INDICATE THE PCPN THINNING OUT AND SPREADING EAST AND WEST OF THE
AREA SO EXPECT DRIZZLE DURING THE MORNING AND INTO THE AFTERNOON
HOURS. PCPN COULD END AROUND 01Z WITH CONDITIONS BECOMING VFR AT
MOST SITES...EXCEPT BMI. WINDS WILL BE EASTERLY AND THEN BECOME
NORTHEASTERLY TOMORROW NIGHT AS THE LOW PRESSURE AREA MOVES
EAST...SOUTH OF THE STATE.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
924 PM EST SUN FEB 5 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE IS GOING TO COVER INDIANA THROUGH MONDAY. A SERIES
OF WEAK DISTURBANCES WILL PASS OVERHEAD LATER THIS WEEK.
HOWEVER...HIGH PRESSURE WILL BE THE RULE AT THE SURFACE SO
PRECIPITATION CHANCES SHOULD STAY SMALL.
&&
.NEAR TERM /TONIGHT/...
MAIN ISSUES ARE TEMPERATURES AND FOG AS MODELS AND OBS ALL SUPPORT
CLEAR TONIGHT.
AT 01Z WINDS IN OBSERVATIONS INDICATED A WEAK SURFACE RIDGE TO OUR
WEST. RUC SAYS THIS WILL WORK EASTWARD AND ALMOST COMPLETELY KILL
OUR WINDS LATE TONIGHT. WITH THAT AND OUR CURRENT TEMPERATURES
ROUGHLY 3 DEGREES BELOW THE HOURLY GRIDS...I AM GOING TO DROP
MINS TONIGHT ABOUT A CATEGORY.
CLEAR WITH LIGHT WIND FAVORS FOG TONIGHT. BUFKIT SHOWS MOISTURE
DECREASING RAPIDLY WITH HEIGHT...A NEGATIVE. WITH OFFSETTING
FACTORS I WILL KEEP FOG IN THE FORECAST BUT WONT MENTION DENSE.
GIVEN DAMP GROUND WE MIGHT GET FOG OUTSIDE THE COMMON LOW SPOTS...SO
I WILL CHANGE COVERAGE TO AREAS FROM PATCHY.
&&
.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 THE 06/03Z IND TAF UPDATE/...
NO CHANGES NECESSARY. PREVIOUS DISCUSSION FOLLOWS.
MAINLY VFR THROUGH THE PERIOD...WITH A PERIOD OF MVFR POSSIBLE NEAR
DAYBREAK TOMORROW.
HIGH PRESSURE HAS BUILT IN...ERODING ANY LEFTOVER CLOUD...AND
ALLOWING SIGNIFICANT DRYING AT THE SURFACE THROUGH A LIGHT NORTHERLY
SURFACE FLOW AND AMPLE SUNSHINE THIS AFTERNOON. ALTHOUGH WINDS WILL
BE CALM TO LIGHT AND SKIES WILL BE CLEAR OVERNIGHT...DO NOT EXPECT
SIGNIFICANT FOG TO FORM. WILL INCLUDE SOME HIGH END MVFR FOG FOR A
FEW HOURS NEAR DAYBREAK AT ALL SITES...BUT EVEN THIS MAY BE SLIGHTLY
PESSIMISTIC. NAM/RUC SOUNDINGS SHOW DECENT SATURATION NEAR THE
SURFACE...GFS/SREF SOUNDINGS DO NOT. NAM SOUNDING IS MOST
FAVORABLE...BUT ITS MOS IS THE ONLY ONE THAT MENTIONS ANY
RESTRICTION TO VISIBILITY AND IT ONLY GOES DOWN TO 5SM.
WINDS WILL BE CALM TO LIGHT OVERNIGHT...BECOMING WEST/SOUTHWESTERLY
TOMORROW BUT REMAINING BELOW 10KT. MAY SEE INFREQUENT GUSTS INTO THE
LOW TEENS BUT SURFACE PRESSURE GRADIENT APPEARS FAIRLY WEAK...SO
WILL NOT INCLUDE ANY MENTION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...CP
LONG TERM....JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
853 PM EST SUN FEB 5 2012
.UPDATE...
THE SYNOPSIS AND NEAR TERM SECTIONS HAVE BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE IS GOING TO COVER INDIANA THROUGH MONDAY. A SERIES
OF WEAK DISTURBANCES WILL PASS OVERHEAD LATER THIS WEEK.
HOWEVER...HIGH PRESSURE WILL BE THE RULE AT THE SURFACE SO
PRECIPITATION CHANCES SHOULD STAY SMALL.
&&
.NEAR TERM /TONIGHT/...
MAIN ISSUES ARE TEMPERATURES AND FOG AS MODELS AND OBS ALL SUPPORT
CLEAR TONIGHT.
AT 01Z WINDS IN OBSERVATIONS INDICATED A WEAK SURFACE RIDGE TO OUR
WEST. RUC SAYS THIS WILL WORK EASTWARD AND ALMOST COMPLETELY KILL
OUR WINDS LATE TONIGHT. WITH THAT AND OUR CURRENT TEMPERATURES
ROUGHLY 3 DEGREES BELOW THE HOURLY GRIDS...I AM GOING TO DROP
MINS TONIGHT ABOUT A CATEGORY.
CLEAR WITH LIGHT WIND FAVORS FOG TONIGHT. BUFKIT SHOWS MOISTURE
DECREASING RAPIDLY WITH HEIGHT...A NEGATIVE. WITH OFFSETTING
FACTORS I WILL KEEP FOG IN THE FORECAST BUT WONT MENTION DENSE.
GIVEN DAMP GROUND WE MIGHT GET FOG OUTSIDE THE COMMON LOW SPOTS...SO
I WILL CHANGE COVERAGE TO AREAS FROM PATCHY.
&&
.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 THE 06/00Z TAFS/...
MAINLY VFR THROUGH THE PERIOD...WITH A PERIOD OF MVFR POSSIBLE NEAR
DAYBREAK TOMORROW.
HIGH PRESSURE HAS BUILT IN...ERODING ANY LEFTOVER CLOUD...AND
ALLOWING SIGNIFICANT DRYING AT THE SURFACE THROUGH A LIGHT NORTHERLY
SURFACE FLOW AND AMPLE SUNSHINE THIS AFTERNOON. ALTHOUGH WINDS WILL
BE CALM TO LIGHT AND SKIES WILL BE CLEAR OVERNIGHT...DO NOT EXPECT
SIGNIFICANT FOG TO FORM. WILL INCLUDE SOME HIGH END MVFR FOG FOR A
FEW HOURS NEAR DAYBREAK AT ALL SITES...BUT EVEN THIS MAY BE SLIGHTLY
PESSIMISTIC. NAM/RUC SOUNDINGS SHOW DECENT SATURATION NEAR THE
SURFACE...GFS/SREF SOUNDINGS DO NOT. NAM SOUNDING IS MOST
FAVORABLE...BUT ITS MOS IS THE ONLY ONE THAT MENTIONS ANY
RESTRICTION TO VISIBILITY AND IT ONLY GOES DOWN TO 5SM.
WINDS WILL BE CALM TO LIGHT OVERNIGHT...BECOMING WEST/SOUTHWESTERLY
TOMORROW BUT REMAINING BELOW 10KT. MAY SEE INFREQUENT GUSTS INTO THE
LOW TEENS BUT SURFACE PRESSURE GRADIENT APPEARS FAIRLY WEAK...SO
WILL NOT INCLUDE ANY MENTION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...CP
LONG TERM....JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
934 AM EST SAT FEB 4 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK EAST THROUGH MISSOURI AND ACROSS THE LOWER
OHIO VALLEY TODAY. THIS WILL BRING RAIN TO CENTRAL INDIANA THROUGH
TONIGHT. HIGH PRESSURE WILL EXPAND INTO THE REGION ON SUNDAY...WITH
DRY MILD WEATHER ANTICIPATED SUNDAY INTO THE MIDDLE OF THE WEEK. A
WEAK UPPER LEVEL DISTURBANCE WILL PASS THROUGH THE REGION WEDNESDAY
WITH THE NEXT CHANCE FOR PRECIPITATION. A SHIFT TO COLDER AND
POTENTIALLY MORE UNSETTLED WEATHER IS EXPECTED BY THE END OF THE
WEEK AS AN UPPER TROUGH SHARPENS OVER THE GREAT LAKES.
&&
.NEAR TERM /TODAY/...
SEEING SOME HIGHER RETURNS ACROSS THE FAR NORTHEAST FORECAST AREA
COINCIDING WITH MIXED PRECIP IN THE OBS AT KMIE AND LIGHT SNOW
BEING REPORTED AT MARION AND LOGANSPORT JUST NORTH OF THE FORECAST
AREA. WENT AHEAD AND ADDED CHANCE FOR LIGHT SNOW MIXING IN WITH
THE RAIN THROUGH 15Z FROM KOKOMO SOUTHEAST THROUGH MUNCIE AND
WINCHESTER. ALSO ADJUSTED HOURLY TEMPS THROUGH THE DAY BASED ON
CURRENT OBS. TEMPS HAVE COOLED A BIT MORE THAN ORIGINALLY THOUGHT.
REST UNCHANGED...EARLY MORNING DISCUSSION FOLLOWS.
LIGHT RAIN SLOWLY EXPANDING AND OVERSPREADING THE FORECAST AREA
EARLY THIS MORNING. TEMPS RANGED FROM THE UPPER 30S TO MID 40S AS OF
08Z.
LOW PRESSURE PASSING THROUGH SOUTHERN MISSOURI AND INTO THE LOWER
OHIO VALLEY REMAINS THE PRIMARY FOCUS FOR THE NEAR TERM. SO
FAR...RESIDUAL DRY AIR IN THE LOW LEVELS HAS REALLY LIMITED RAINFALL
ACROSS THE REGION. LAPS SOUNDINGS SHOWING THE SATURATION OF THE
BOUNDARY LAYER IS HAVING TO CONTEND WITH EASTERLY FLOW IN THE LOW
LEVELS. AS BETTER LIFT AND FORCING ARRIVES THROUGH DAYBREAK...
BOUNDARY LAYER SHOULD SATURATE FULLY WITH PRECIPITATION BECOMING
WIDESPREAD. SOUNDING DATA AND RUC/06Z NAM BOTH SHOWING BOUNDARY
LAYER TEMPS NEAR/JUST BELOW FREEZING FOR A FEW HOURS THIS MORNING
GRAZING NORTHERN COUNTIES. EVEN WITH SURFACE TEMPS REMAINING IN THE
UPPER 30S...THIS COOLING ALOFT MAY BE ENOUGH TO ALLOW A FEW FLAKES
TO MIX IN WITH THE RAIN THIS MORNING FOR NORTHERN PORTIONS OF THE
FORECAST AREA. WITH THAT BEING SAID...ANY SNOW/MIX PRECIP REPORTS SO
FAR HAVE BEEN CONFINED TO NORTHERN PORTIONS OF INDIANA/ILLINOIS IN
CLOSE PROXIMITY TO DEFORMATION BAND THROUGH THE MID LEVELS. LEAVING
ANY MIX OF RA/SN MENTION OUT OF THE FORECAST OVER NORTHERN COUNTIES
THIS MORNING AS CONFIDENCE REMAINS LOW IN THIS OCCURRING AT THIS
TIME. WILL CONTINUE TO MONITOR OBSERVATIONS CLOSELY AND ADJUST AS
NECESSARY.
MOST RECENT SHORT RANGE MODEL GUIDANCE FROM THE HRRR AND RUC BOTH
BRINGING AREA OF STEADIER RAINFALL CURRENTLY ACROSS ILLINOIS THROUGH
THE FORECAST AREA THIS MORNING. DEEPER MOISTURE AND STRONGER FORCING
SHIFTS EAST BY EARLY AFTERNOON WITH RAINFALL INTENSITY EXPECTED TO
DROP OFF TO JUST LIGHT RAIN OR DRIZZLE AS THE LOWEST 8-10KFT REMAIN
SATURATED. WILL CARRY CATEGORICAL POPS THIS MORNING...DROPPING POPS
BACK FOR THE AFTERNOON AS DRIER AIR ALOFT STEADILY PRESSES INTO THE
REGION FROM THE SOUTHWEST. E/NE WINDS AT 10-15MPH WITH A FEW GUSTS
TO AROUND 20 MPH FOR MUCH OF THE DAY WILL MAKE FOR RAW CHILLY
CONDITIONS.
TEMPS...TRICKY SETUP FOR TEMPS TODAY AS MOST LOCATIONS ARE LIKELY TO
EXPERIENCE HIGHS SHORTLY AFTER DAYBREAK. COMBINATION OF THICK
STRATUS DECK...PRECIPITATION AND STEADY EAST/NORTHEAST FLOW IN THE
LOW LEVELS DOES NOT APPEAR CONDUCIVE AT ALL TO MUCH OF A RISE IN
TEMPS LATER TODAY. 850MB TEMPS DO WARM A BIT INTO THE AFTERNOON AND
THAT MAY BE GOOD FOR A BUMP IN TEMPS OF A COUPLE DEGREES ONCE THE
STEADIER RAIN SHIFTS EAST. NORTHERN COUNTIES MAY REMAIN IN THE 30S
ALL DAY.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST CHALLENGES IN THE SHORT TERM FOCUS ON ENDING OF THE PRECIP
THIS EVENING AND TEMPS THEREAFTER AS HIGH PRESSURE EXPANDS INTO THE
REGION.
MODELS CONTINUE TO FAVOR A FASTER ENDING TO PRECIP LATE TONIGHT.
UPPER LOW REMAINS BEHIND WITH LITTLE MOISTURE AND FORCING TO WORK
WITH AS THE SURFACE WAVE MOVES QUICKLY EAST INTO THE CENTRAL
APPALACHIANS. DRIER AIR AND SUBSIDENCE WITH HIGH PRESSURE RIDGE OVER
THE WESTERN GREAT LAKES ADVECT SOUTH LATE TONIGHT AND SERVE TO
OVERWHELM ANY REMAINING LOW LEVEL MOISTURE. WITH LACK OF ANY
SIGNIFICANT FORCING...ANTICIPATE LIGHT RAIN/DRIZZLE WILL END FROM
NORTH TO SOUTH FROM LATE EVENING INTO THE OVERNIGHT. AREAS NORTH OF
I-70 SHOULD BE MAINLY DRY FROM MIDNIGHT ON WITH PRECIP ENDING AT
LOCATIONS FURTHER SOUTH PRIOR TO DAYBREAK SUNDAY. BOUNDARY LAYER
WILL BEGIN COOLING DURING THE EVENING BUT DEEPER MOISTURE AND MOST
IF NOT ALL PRECIP SHOULD BE FINISHED BEFORE CONDITIONS BECOME
SUPPORTIVE FOR LIGHT SNOW TO MIX IN. WHILE A FEW FLAKES ARE
CERTAINLY NOT OUT OF THE QUESTION...CHANCES APPEAR SO LOW TO KEEP
ANY MENTION OUT OF THE FORECAST AT THIS TIME. MODEL SOUNDINGS ALSO
SHOW RAPID DRYING INTO THE LOW LEVELS LATE TONIGHT WITH NORTHERN
COUNTIES LIKELY TO CLEAR PRIOR TO DAYBREAK.
DESPITE THE REMNANT UPPER LEVEL FEATURE DRIFTING THROUGH THE LOWER
OHIO VALLEY THROUGH SUNDAY NIGHT...PRESENCE OF DEEP SUBSIDENCE AND
DRY AIR ASSOCIATED WITH THE BROAD HIGH PRESSURE RIDGE WILL PROVIDE
TRANQUIL WEATHER FOR THE REMAINDER OF THE PERIOD THROUGH MONDAY
NIGHT. ANY LINGERING CLOUDS SUNDAY MORNING WILL QUICKLY BE PUSHED
OFF TO THE SOUTH AS DRIER AIR FULLY TAKES HOLD OVER CENTRAL INDIANA.
MODEL SOUNDINGS SHOW ABUNDANCE OF SUBSIDENT AIR AND RESULT SHOULD BE
MAINLY SUNNY SKIES FOR SUNDAY WITH LIGHT NORTHERLY FLOW. MAINLY
CLEAR SKIES WILL CONTINUE SUNDAY NIGHT AND INTO MONDAY AS THE HIGH
PRESSURE RIDGE REMAINS THE DOMINANT WEATHER FEATURE OVER THE REGION.
MAY SEE A FEW CLOUDS MONDAY NIGHT AS A WEAK DISTURBANCE ALOFT MOVES
INTO THE GREAT LAKES.
TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE THROUGH THE PERIOD AS
HIGH TEMPS RECOVER INTO THE MID AND UPPER 40S FOR MUCH OF THE
FORECAST AREA ON BOTH SUNDAY AND MONDAY. LEANED TOWARDS COOLER
MAVMOS SUNDAY NIGHT WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE MAIN CONCERN DURING THE PERIOD IS PRECIPITATION CHANCES
ASSOCIATED WITH SEVERAL UPPER WAVES PASSING THROUGH THE FORECAST
AREA.
ALL MODELS BRIEFLY SHOW WEAK UPPER LEVEL RIDGING EARLY TUESDAY WHICH
WILL KEEP CONDITIONS DRY. HOWEVER...CLOUD COVER LOOKS TO INCREASE
THROUGHOUT THE DAY AS THE RIDGE BEGINS TO FLATTEN PRIOR TO THE
ARRIVAL OF THE FIRST WAVE. THIS WILL HAVE AN IMPACT ON TEMPERATURES
WITH READINGS EXPECTED TO BE NOT QUITE AS HIGH AS MONDAY...ALTHOUGH
STILL ABOVE AVERAGE.
ALL MODELS DEPICT AN UPPER LEVEL WAVE PASSING THROUGH ON WEDNESDAY
WITH THE GFS AND CANADIAN IN GOOD AGREEMENT WITH REGARDS TO TIMING
WHILE THE ECMWF IS MUCH SLOWER. WENT WITH SLIGHT CHANCE POPS FOR
WEDNESDAY AND EARLY THURSDAY TO ACCOUNT FOR THE SLOWER ECMWF
SOLUTION. ALLBLEND INITIALIZATION APPEARS TO HAVE A GOOD HANDLE ON
THIS COMPROMISE. PRECIPITATION TYPE COULD ALSO BE A CONCERN WITH
THICKNESS VALUES POSSIBLY BELOW 530 DM. THEREFORE...WENT WITH A
RAIN/SNOW MIX FOR WEDNESDAY BEFORE TRANSITIONING TO ALL SNOW HEADING
INTO THURSDAY.
A STRONG UPPER LOW LOOKS TO DEVELOP NEAR HUDSON BAY BY LATE IN THE
PERIOD. THIS SYSTEM COULD EJECT A FEW MORE WAVES ACROSS THE FORECAST
AREA LATE IN THE WORK WEEK AND INTO THE WEEKEND BUT WILL STICK WITH
A DRY FORECAST UNTIL THE MODELS HAVE A BETTER HANDLE ON THE TIMING
OF ANY WAVES.
&&
.AVIATION /DISCUSSION FOR THE 041500Z TAF UPDATE/...
HEAVIER RAIN HAS MOVED EAST OF ALL SITES BUT KBMG AT THIS POINT. IN
THE WAKE OF THE STRONGER AREA OF LIFT THAT HAS MOVED OFF TO THE
EAST...IFR CEILINGS 006-008 AGL ARE DEVELOPING/ADVECTING IN TO THE
SITES. BASED ON UPSTREAM OBSERVATIONS AND MODEL SOUNDINGS EXPECT
THESE TO LINGER FOR THE REST OF DAY AND INTO THE OVERNIGHT HOURS. A
BIT OF MODEL DISAGREEMENT ON WHEN CONDITIONS WILL IMPROVE...WITH THE
MOST OPTIMISTIC BEING AROUND 6Z AND THE MOST PESSIMISTIC NOT TIL
AFTER 15Z. A MIDDLE OF THE ROAD SOLUTION IS AROUND 10Z AND WILL GO
WITH THAT AT THIS TIME. AREAS OF LIGHT RAIN/DRIZZLE EXPECTED AS WELL
TODAY...BUT THINK PRECIPITATION WILL BE LIGHT ENOUGH IN A FEW HOURS
TO KEEP VISIBILITY RESTRICTIONS ABOVE IFR FOR THE MOST PART.
MODEL DATA SUGGEST SURFACE WIND GUSTS UP TO 20-22KTS FROM 060-090
HEADINGS PROBABLE FROM THE MID MORNING HOURS INTO THE AFTERNOON.
ALREADY SEEING THESE GUSTS ACROSS ILLINOIS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...JAS/CP
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
656 AM EST SAT FEB 4 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK EAST THROUGH MISSOURI AND ACROSS THE LOWER
OHIO VALLEY TODAY. THIS WILL BRING RAIN TO CENTRAL INDIANA THROUGH
TONIGHT. HIGH PRESSURE WILL EXPAND INTO THE REGION ON SUNDAY...WITH
DRY MILD WEATHER ANTICIPATED SUNDAY INTO THE MIDDLE OF THE WEEK. A
WEAK UPPER LEVEL DISTURBANCE WILL PASS THROUGH THE REGION WEDNESDAY
WITH THE NEXT CHANCE FOR PRECIPITATION. A SHIFT TO COLDER AND
POTENTIALLY MORE UNSETTLED WEATHER IS EXPECTED BY THE END OF THE
WEEK AS AN UPPER TROUGH SHARPENS OVER THE GREAT LAKES.
&&
.NEAR TERM /TODAY/...
SEEING SOME HIGHER RETURNS ACROSS THE FAR NORTHEAST FORECAST AREA
COINCIDING WITH MIXED PRECIP IN THE OBS AT KMIE AND LIGHT SNOW
BEING REPORTED AT MARION AND LOGANSPORT JUST NORTH OF THE FORECAST
AREA. WENT AHEAD AND ADDED CHANCE FOR LIGHT SNOW MIXING IN WITH
THE RAIN THROUGH 15Z FROM KOKOMO SOUTHEAST THROUGH MUNCIE AND
WINCHESTER. ALSO ADJUSTED HOURLY TEMPS THROUGH THE DAY BASED ON
CURRENT OBS. TEMPS HAVE COOLED A BIT MORE THAN ORIGINALLY THOUGHT.
REST UNCHANGED...EARLY MORNING DISCUSSION FOLLOWS.
LIGHT RAIN SLOWLY EXPANDING AND OVERSPREADING THE FORECAST AREA
EARLY THIS MORNING. TEMPS RANGED FROM THE UPPER 30S TO MID 40S AS OF
08Z.
LOW PRESSURE PASSING THROUGH SOUTHERN MISSOURI AND INTO THE LOWER
OHIO VALLEY REMAINS THE PRIMARY FOCUS FOR THE NEAR TERM. SO
FAR...RESIDUAL DRY AIR IN THE LOW LEVELS HAS REALLY LIMITED RAINFALL
ACROSS THE REGION. LAPS SOUNDINGS SHOWING THE SATURATION OF THE
BOUNDARY LAYER IS HAVING TO CONTEND WITH EASTERLY FLOW IN THE LOW
LEVELS. AS BETTER LIFT AND FORCING ARRIVES THROUGH DAYBREAK...
BOUNDARY LAYER SHOULD SATURATE FULLY WITH PRECIPITATION BECOMING
WIDESPREAD. SOUNDING DATA AND RUC/06Z NAM BOTH SHOWING BOUNDARY
LAYER TEMPS NEAR/JUST BELOW FREEZING FOR A FEW HOURS THIS MORNING
GRAZING NORTHERN COUNTIES. EVEN WITH SURFACE TEMPS REMAINING IN THE
UPPER 30S...THIS COOLING ALOFT MAY BE ENOUGH TO ALLOW A FEW FLAKES
TO MIX IN WITH THE RAIN THIS MORNING FOR NORTHERN PORTIONS OF THE
FORECAST AREA. WITH THAT BEING SAID...ANY SNOW/MIX PRECIP REPORTS SO
FAR HAVE BEEN CONFINED TO NORTHERN PORTIONS OF INDIANA/ILLINOIS IN
CLOSE PROXIMITY TO DEFORMATION BAND THROUGH THE MID LEVELS. LEAVING
ANY MIX OF RA/SN MENTION OUT OF THE FORECAST OVER NORTHERN COUNTIES
THIS MORNING AS CONFIDENCE REMAINS LOW IN THIS OCCURRING AT THIS
TIME. WILL CONTINUE TO MONITOR OBSERVATIONS CLOSELY AND ADJUST AS
NECESSARY.
MOST RECENT SHORT RANGE MODEL GUIDANCE FROM THE HRRR AND RUC BOTH
BRINGING AREA OF STEADIER RAINFALL CURRENTLY ACROSS ILLINOIS THROUGH
THE FORECAST AREA THIS MORNING. DEEPER MOISTURE AND STRONGER FORCING
SHIFTS EAST BY EARLY AFTERNOON WITH RAINFALL INTENSITY EXPECTED TO
DROP OFF TO JUST LIGHT RAIN OR DRIZZLE AS THE LOWEST 8-10KFT REMAIN
SATURATED. WILL CARRY CATEGORICAL POPS THIS MORNING...DROPPING POPS
BACK FOR THE AFTERNOON AS DRIER AIR ALOFT STEADILY PRESSES INTO THE
REGION FROM THE SOUTHWEST. E/NE WINDS AT 10-15MPH WITH A FEW GUSTS
TO AROUND 20 MPH FOR MUCH OF THE DAY WILL MAKE FOR RAW CHILLY
CONDITIONS.
TEMPS...TRICKY SETUP FOR TEMPS TODAY AS MOST LOCATIONS ARE LIKELY TO
EXPERIENCE HIGHS SHORTLY AFTER DAYBREAK. COMBINATION OF THICK
STRATUS DECK...PRECIPITATION AND STEADY EAST/NORTHEAST FLOW IN THE
LOW LEVELS DOES NOT APPEAR CONDUCIVE AT ALL TO MUCH OF A RISE IN
TEMPS LATER TODAY. 850MB TEMPS DO WARM A BIT INTO THE AFTERNOON AND
THAT MAY BE GOOD FOR A BUMP IN TEMPS OF A COUPLE DEGREES ONCE THE
STEADIER RAIN SHIFTS EAST. NORTHERN COUNTIES MAY REMAIN IN THE 30S
ALL DAY.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST CHALLENGES IN THE SHORT TERM FOCUS ON ENDING OF THE PRECIP
THIS EVENING AND TEMPS THEREAFTER AS HIGH PRESSURE EXPANDS INTO THE
REGION.
MODELS CONTINUE TO FAVOR A FASTER ENDING TO PRECIP LATE TONIGHT.
UPPER LOW REMAINS BEHIND WITH LITTLE MOISTURE AND FORCING TO WORK
WITH AS THE SURFACE WAVE MOVES QUICKLY EAST INTO THE CENTRAL
APPALACHIANS. DRIER AIR AND SUBSIDENCE WITH HIGH PRESSURE RIDGE OVER
THE WESTERN GREAT LAKES ADVECT SOUTH LATE TONIGHT AND SERVE TO
OVERWHELM ANY REMAINING LOW LEVEL MOISTURE. WITH LACK OF ANY
SIGNIFICANT FORCING...ANTICIPATE LIGHT RAIN/DRIZZLE WILL END FROM
NORTH TO SOUTH FROM LATE EVENING INTO THE OVERNIGHT. AREAS NORTH OF
I-70 SHOULD BE MAINLY DRY FROM MIDNIGHT ON WITH PRECIP ENDING AT
LOCATIONS FURTHER SOUTH PRIOR TO DAYBREAK SUNDAY. BOUNDARY LAYER
WILL BEGIN COOLING DURING THE EVENING BUT DEEPER MOISTURE AND MOST
IF NOT ALL PRECIP SHOULD BE FINISHED BEFORE CONDITIONS BECOME
SUPPORTIVE FOR LIGHT SNOW TO MIX IN. WHILE A FEW FLAKES ARE
CERTAINLY NOT OUT OF THE QUESTION...CHANCES APPEAR SO LOW TO KEEP
ANY MENTION OUT OF THE FORECAST AT THIS TIME. MODEL SOUNDINGS ALSO
SHOW RAPID DRYING INTO THE LOW LEVELS LATE TONIGHT WITH NORTHERN
COUNTIES LIKELY TO CLEAR PRIOR TO DAYBREAK.
DESPITE THE REMNANT UPPER LEVEL FEATURE DRIFTING THROUGH THE LOWER
OHIO VALLEY THROUGH SUNDAY NIGHT...PRESENCE OF DEEP SUBSIDENCE AND
DRY AIR ASSOCIATED WITH THE BROAD HIGH PRESSURE RIDGE WILL PROVIDE
TRANQUIL WEATHER FOR THE REMAINDER OF THE PERIOD THROUGH MONDAY
NIGHT. ANY LINGERING CLOUDS SUNDAY MORNING WILL QUICKLY BE PUSHED
OFF TO THE SOUTH AS DRIER AIR FULLY TAKES HOLD OVER CENTRAL INDIANA.
MODEL SOUNDINGS SHOW ABUNDANCE OF SUBSIDENT AIR AND RESULT SHOULD BE
MAINLY SUNNY SKIES FOR SUNDAY WITH LIGHT NORTHERLY FLOW. MAINLY
CLEAR SKIES WILL CONTINUE SUNDAY NIGHT AND INTO MONDAY AS THE HIGH
PRESSURE RIDGE REMAINS THE DOMINANT WEATHER FEATURE OVER THE REGION.
MAY SEE A FEW CLOUDS MONDAY NIGHT AS A WEAK DISTURBANCE ALOFT MOVES
INTO THE GREAT LAKES.
TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE THROUGH THE PERIOD AS
HIGH TEMPS RECOVER INTO THE MID AND UPPER 40S FOR MUCH OF THE
FORECAST AREA ON BOTH SUNDAY AND MONDAY. LEANED TOWARDS COOLER
MAVMOS SUNDAY NIGHT WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE MAIN CONCERN DURING THE PERIOD IS PRECIPITATION CHANCES
ASSOCIATED WITH SEVERAL UPPER WAVES PASSING THROUGH THE FORECAST
AREA.
ALL MODELS BRIEFLY SHOW WEAK UPPER LEVEL RIDGING EARLY TUESDAY WHICH
WILL KEEP CONDITIONS DRY. HOWEVER...CLOUD COVER LOOKS TO INCREASE
THROUGHOUT THE DAY AS THE RIDGE BEGINS TO FLATTEN PRIOR TO THE
ARRIVAL OF THE FIRST WAVE. THIS WILL HAVE AN IMPACT ON TEMPERATURES
WITH READINGS EXPECTED TO BE NOT QUITE AS HIGH AS MONDAY...ALTHOUGH
STILL ABOVE AVERAGE.
ALL MODELS DEPICT AN UPPER LEVEL WAVE PASSING THROUGH ON WEDNESDAY
WITH THE GFS AND CANADIAN IN GOOD AGREEMENT WITH REGARDS TO TIMING
WHILE THE ECMWF IS MUCH SLOWER. WENT WITH SLIGHT CHANCE POPS FOR
WEDNESDAY AND EARLY THURSDAY TO ACCOUNT FOR THE SLOWER ECMWF
SOLUTION. ALLBLEND INITIALIZATION APPEARS TO HAVE A GOOD HANDLE ON
THIS COMPROMISE. PRECIPITATION TYPE COULD ALSO BE A CONCERN WITH
THICKNESS VALUES POSSIBLY BELOW 530 DM. THEREFORE...WENT WITH A
RAIN/SNOW MIX FOR WEDNESDAY BEFORE TRANSITIONING TO ALL SNOW HEADING
INTO THURSDAY.
A STRONG UPPER LOW LOOKS TO DEVELOP NEAR HUDSON BAY BY LATE IN THE
PERIOD. THIS SYSTEM COULD EJECT A FEW MORE WAVES ACROSS THE FORECAST
AREA LATE IN THE WORK WEEK AND INTO THE WEEKEND BUT WILL STICK WITH
A DRY FORECAST UNTIL THE MODELS HAVE A BETTER HANDLE ON THE TIMING
OF ANY WAVES.
&&
.AVIATION /DISCUSSION FOR THE 041200Z TAFS/...
RADAR TRENDS AND SHORT TERM MODEL DATA SUGGEST THE BEST
LIFT/HEAVIEST PRECIPITATION WILL PASS OVER THE TAF SITES THROUGH
ABOUT 041600Z. EXPECTING CEILINGS TO FALL INTO THE 015-025 RANGE
DURING THE COURSE OF THE MORNING WITH IFR VISIBILITY RESTRICTIONS
IN THE HEAVIER RAINFALL AREAS. ONCE STRONGER AREA OF LIFT TAILS
OFF...EXPECTING IFR CEILINGS 006-008 AGL TO DEVELOP BY THE MID TO
LATE MORNING HOURS AND LINGER FOR THE REST OF DAY. AREAS OF LIGHT
RAIN/DRIZZLE EXPECTED AS WELL...BUT THINK PRECIPITATION WILL BE
LIGHT ENOUGH LATER TODAY TO KEEP VISIBILITY RESTRICTIONS ABOVE IFR
FOR THE MOST PART.
MODEL DATA SUGGEST SURFACE WIND GUSTS UP TO 20-22KTS FROM 060-090
HEADINGS PROBABLE FROM THE MID MORNING HOURS INTO THE AFTERNOON.
ALREADY SEEING THESE GUSTS ACROSS ILLINOIS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
530 AM EST SAT FEB 4 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK EAST THROUGH MISSOURI AND ACROSS THE LOWER
OHIO VALLEY TODAY. THIS WILL BRING RAIN TO CENTRAL INDIANA THROUGH
TONIGHT. HIGH PRESSURE WILL EXPAND INTO THE REGION ON SUNDAY...WITH
DRY MILD WEATHER ANTICIPATED SUNDAY INTO THE MIDDLE OF THE WEEK. A
WEAK UPPER LEVEL DISTURBANCE WILL PASS THROUGH THE REGION WEDNESDAY
WITH THE NEXT CHANCE FOR PRECIPITATION. A SHIFT TO COLDER AND
POTENTIALLY MORE UNSETTLED WEATHER IS EXPECTED BY THE END OF THE
WEEK AS AN UPPER TROUGH SHARPENS OVER THE GREAT LAKES.
&&
.NEAR TERM /TODAY/...
LIGHT RAIN SLOWLY EXPANDING AND OVERSPREADING THE FORECAST AREA
EARLY THIS MORNING. TEMPS RANGED FROM THE UPPER 30S TO MID 40S AS OF
08Z.
LOW PRESSURE PASSING THROUGH SOUTHERN MISSOURI AND INTO THE LOWER
OHIO VALLEY REMAINS THE PRIMARY FOCUS FOR THE NEAR TERM. SO
FAR...RESIDUAL DRY AIR IN THE LOW LEVELS HAS REALLY LIMITED RAINFALL
ACROSS THE REGION. LAPS SOUNDINGS SHOWING THE SATURATION OF THE
BOUNDARY LAYER IS HAVING TO CONTEND WITH EASTERLY FLOW IN THE LOW
LEVELS. AS BETTER LIFT AND FORCING ARRIVES THROUGH DAYBREAK...
BOUNDARY LAYER SHOULD SATURATE FULLY WITH PRECIPITATION BECOMING
WIDESPREAD. SOUNDING DATA AND RUC/06Z NAM BOTH SHOWING BOUNDARY
LAYER TEMPS NEAR/JUST BELOW FREEZING FOR A FEW HOURS THIS MORNING
GRAZING NORTHERN COUNTIES. EVEN WITH SURFACE TEMPS REMAINING IN THE
UPPER 30S...THIS COOLING ALOFT MAY BE ENOUGH TO ALLOW A FEW FLAKES
TO MIX IN WITH THE RAIN THIS MORNING FOR NORTHERN PORTIONS OF THE
FORECAST AREA. WITH THAT BEING SAID...ANY SNOW/MIX PRECIP REPORTS SO
FAR HAVE BEEN CONFINED TO NORTHERN PORTIONS OF INDIANA/ILLINOIS IN
CLOSE PROXIMITY TO DEFORMATION BAND THROUGH THE MID LEVELS. LEAVING
ANY MIX OF RA/SN MENTION OUT OF THE FORECAST OVER NORTHERN COUNTIES
THIS MORNING AS CONFIDENCE REMAINS LOW IN THIS OCCURRING AT THIS
TIME. WILL CONTINUE TO MONITOR OBSERVATIONS CLOSELY AND ADJUST AS
NECESSARY.
MOST RECENT SHORT RANGE MODEL GUIDANCE FROM THE HRRR AND RUC BOTH
BRINGING AREA OF STEADIER RAINFALL CURRENTLY ACROSS ILLINOIS THROUGH
THE FORECAST AREA THIS MORNING. DEEPER MOISTURE AND STRONGER FORCING
SHIFTS EAST BY EARLY AFTERNOON WITH RAINFALL INTENSITY EXPECTED TO
DROP OFF TO JUST LIGHT RAIN OR DRIZZLE AS THE LOWEST 8-10KFT REMAIN
SATURATED. WILL CARRY CATEGORICAL POPS THIS MORNING...DROPPING POPS
BACK FOR THE AFTERNOON AS DRIER AIR ALOFT STEADILY PRESSES INTO THE
REGION FROM THE SOUTHWEST. E/NE WINDS AT 10-15MPH WITH A FEW GUSTS
TO AROUND 20 MPH FOR MUCH OF THE DAY WILL MAKE FOR RAW CHILLY
CONDITIONS.
TEMPS...TRICKY SETUP FOR TEMPS TODAY AS MOST LOCATIONS ARE LIKELY TO
EXPERIENCE HIGHS SHORTLY AFTER DAYBREAK. COMBINATION OF THICK
STRATUS DECK...PRECIPITATION AND STEADY EAST/NORTHEAST FLOW IN THE
LOW LEVELS DOES NOT APPEAR CONDUCIVE AT ALL TO MUCH OF A RISE IN
TEMPS LATER TODAY. 850MB TEMPS DO WARM A BIT INTO THE AFTERNOON AND
THAT MAY BE GOOD FOR A BUMP IN TEMPS OF A COUPLE DEGREES ONCE THE
STEADIER RAIN SHIFTS EAST. NORTHERN COUNTIES MAY REMAIN IN THE 30S
ALL DAY.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST CHALLENGES IN THE SHORT TERM FOCUS ON ENDING OF THE PRECIP
THIS EVENING AND TEMPS THEREAFTER AS HIGH PRESSURE EXPANDS INTO THE
REGION.
MODELS CONTINUE TO FAVOR A FASTER ENDING TO PRECIP LATE TONIGHT.
UPPER LOW REMAINS BEHIND WITH LITTLE MOISTURE AND FORCING TO WORK
WITH AS THE SURFACE WAVE MOVES QUICKLY EAST INTO THE CENTRAL
APPALACHIANS. DRIER AIR AND SUBSIDENCE WITH HIGH PRESSURE RIDGE OVER
THE WESTERN GREAT LAKES ADVECT SOUTH LATE TONIGHT AND SERVE TO
OVERWHELM ANY REMAINING LOW LEVEL MOISTURE. WITH LACK OF ANY
SIGNIFICANT FORCING...ANTICIPATE LIGHT RAIN/DRIZZLE WILL END FROM
NORTH TO SOUTH FROM LATE EVENING INTO THE OVERNIGHT. AREAS NORTH OF
I-70 SHOULD BE MAINLY DRY FROM MIDNIGHT ON WITH PRECIP ENDING AT
LOCATIONS FURTHER SOUTH PRIOR TO DAYBREAK SUNDAY. BOUNDARY LAYER
WILL BEGIN COOLING DURING THE EVENING BUT DEEPER MOISTURE AND MOST
IF NOT ALL PRECIP SHOULD BE FINISHED BEFORE CONDITIONS BECOME
SUPPORTIVE FOR LIGHT SNOW TO MIX IN. WHILE A FEW FLAKES ARE
CERTAINLY NOT OUT OF THE QUESTION...CHANCES APPEAR SO LOW TO KEEP
ANY MENTION OUT OF THE FORECAST AT THIS TIME. MODEL SOUNDINGS ALSO
SHOW RAPID DRYING INTO THE LOW LEVELS LATE TONIGHT WITH NORTHERN
COUNTIES LIKELY TO CLEAR PRIOR TO DAYBREAK.
DESPITE THE REMNANT UPPER LEVEL FEATURE DRIFTING THROUGH THE LOWER
OHIO VALLEY THROUGH SUNDAY NIGHT...PRESENCE OF DEEP SUBSIDENCE AND
DRY AIR ASSOCIATED WITH THE BROAD HIGH PRESSURE RIDGE WILL PROVIDE
TRANQUIL WEATHER FOR THE REMAINDER OF THE PERIOD THROUGH MONDAY
NIGHT. ANY LINGERING CLOUDS SUNDAY MORNING WILL QUICKLY BE PUSHED
OFF TO THE SOUTH AS DRIER AIR FULLY TAKES HOLD OVER CENTRAL INDIANA.
MODEL SOUNDINGS SHOW ABUNDANCE OF SUBSIDENT AIR AND RESULT SHOULD BE
MAINLY SUNNY SKIES FOR SUNDAY WITH LIGHT NORTHERLY FLOW. MAINLY
CLEAR SKIES WILL CONTINUE SUNDAY NIGHT AND INTO MONDAY AS THE HIGH
PRESSURE RIDGE REMAINS THE DOMINANT WEATHER FEATURE OVER THE REGION.
MAY SEE A FEW CLOUDS MONDAY NIGHT AS A WEAK DISTURBANCE ALOFT MOVES
INTO THE GREAT LAKES.
TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE THROUGH THE PERIOD AS
HIGH TEMPS RECOVER INTO THE MID AND UPPER 40S FOR MUCH OF THE
FORECAST AREA ON BOTH SUNDAY AND MONDAY. LEANED TOWARDS COOLER
MAVMOS SUNDAY NIGHT WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE MAIN CONCERN DURING THE PERIOD IS PRECIPITATION CHANCES
ASSOCIATED WITH SEVERAL UPPER WAVES PASSING THROUGH THE FORECAST
AREA.
ALL MODELS BRIEFLY SHOW WEAK UPPER LEVEL RIDGING EARLY TUESDAY WHICH
WILL KEEP CONDITIONS DRY. HOWEVER...CLOUD COVER LOOKS TO INCREASE
THROUGHOUT THE DAY AS THE RIDGE BEGINS TO FLATTEN PRIOR TO THE
ARRIVAL OF THE FIRST WAVE. THIS WILL HAVE AN IMPACT ON TEMPERATURES
WITH READINGS EXPECTED TO BE NOT QUITE AS HIGH AS MONDAY...ALTHOUGH
STILL ABOVE AVERAGE.
ALL MODELS DEPICT AN UPPER LEVEL WAVE PASSING THROUGH ON WEDNESDAY
WITH THE GFS AND CANADIAN IN GOOD AGREEMENT WITH REGARDS TO TIMING
WHILE THE ECMWF IS MUCH SLOWER. WENT WITH SLIGHT CHANCE POPS FOR
WEDNESDAY AND EARLY THURSDAY TO ACCOUNT FOR THE SLOWER ECMWF
SOLUTION. ALLBLEND INITIALIZATION APPEARS TO HAVE A GOOD HANDLE ON
THIS COMPROMISE. PRECIPITATION TYPE COULD ALSO BE A CONCERN WITH
THICKNESS VALUES POSSIBLY BELOW 530 DM. THEREFORE...WENT WITH A
RAIN/SNOW MIX FOR WEDNESDAY BEFORE TRANSITIONING TO ALL SNOW HEADING
INTO THURSDAY.
A STRONG UPPER LOW LOOKS TO DEVELOP NEAR HUDSON BAY BY LATE IN THE
PERIOD. THIS SYSTEM COULD EJECT A FEW MORE WAVES ACROSS THE FORECAST
AREA LATE IN THE WORK WEEK AND INTO THE WEEKEND BUT WILL STICK WITH
A DRY FORECAST UNTIL THE MODELS HAVE A BETTER HANDLE ON THE TIMING
OF ANY WAVES.
&&
.AVIATION /DISCUSSION FOR THE 041200Z TAFS/...
RADAR TRENDS AND SHORT TERM MODEL DATA SUGGEST THE BEST
LIFT/HEAVIEST PRECIPITATION WILL PASS OVER THE TAF SITES THROUGH
ABOUT 041600Z. EXPECTING CEILINGS TO FALL INTO THE 015-025 RANGE
DURING THE COURSE OF THE MORNING WITH IFR VISIBILITY RESTRICTIONS
IN THE HEAVIER RAINFALL AREAS. ONCE STRONGER AREA OF LIFT TAILS
OFF...EXPECTING IFR CEILINGS 006-008 AGL TO DEVELOP BY THE MID TO
LATE MORNING HOURS AND LINGER FOR THE REST OF DAY. AREAS OF LIGHT
RAIN/DRIZZLE EXPECTED AS WELL...BUT THINK PRECIPITATION WILL BE
LIGHT ENOUGH LATER TODAY TO KEEP VISIBILITY RESTRICTIONS ABOVE IFR
FOR THE MOST PART.
MODEL DATA SUGGEST SURFACE WIND GUSTS UP TO 20-22KTS FROM 060-090
HEADINGS PROBABLE FROM THE MID MORNING HOURS INTO THE AFTERNOON.
ALREADY SEEING THESE GUSTS ACROSS ILLINOIS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...JAS
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
350 AM EST SAT FEB 4 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
LOW PRESSURE WILL TRACK EAST THROUGH MISSOURI AND ACROSS THE LOWER
OHIO VALLEY TODAY. THIS WILL BRING RAIN TO CENTRAL INDIANA THROUGH
TONIGHT. HIGH PRESSURE WILL EXPAND INTO THE REGION ON SUNDAY...WITH
DRY MILD WEATHER ANTICIPATED SUNDAY INTO THE MIDDLE OF THE WEEK. A
WEAK UPPER LEVEL DISTURBANCE WILL PASS THROUGH THE REGION WEDNESDAY
WITH THE NEXT CHANCE FOR PRECIPITATION. A SHIFT TO COLDER AND
POTENTIALLY MORE UNSETTLED WEATHER IS EXPECTED BY THE END OF THE
WEEK AS AN UPPER TROUGH SHARPENS OVER THE GREAT LAKES.
&&
.NEAR TERM /TODAY/...
LIGHT RAIN SLOWLY EXPANDING AND OVERSPREADING THE FORECAST AREA
EARLY THIS MORNING. TEMPS RANGED FROM THE UPPER 30S TO MID 40S AS OF
08Z.
LOW PRESSURE PASSING THROUGH SOUTHERN MISSOURI AND INTO THE LOWER
OHIO VALLEY REMAINS THE PRIMARY FOCUS FOR THE NEAR TERM. SO
FAR...RESIDUAL DRY AIR IN THE LOW LEVELS HAS REALLY LIMITED RAINFALL
ACROSS THE REGION. LAPS SOUNDINGS SHOWING THE SATURATION OF THE
BOUNDARY LAYER IS HAVING TO CONTEND WITH EASTERLY FLOW IN THE LOW
LEVELS. AS BETTER LIFT AND FORCING ARRIVES THROUGH DAYBREAK...
BOUNDARY LAYER SHOULD SATURATE FULLY WITH PRECIPITATION BECOMING
WIDESPREAD. SOUNDING DATA AND RUC/06Z NAM BOTH SHOWING BOUNDARY
LAYER TEMPS NEAR/JUST BELOW FREEZING FOR A FEW HOURS THIS MORNING
GRAZING NORTHERN COUNTIES. EVEN WITH SURFACE TEMPS REMAINING IN THE
UPPER 30S...THIS COOLING ALOFT MAY BE ENOUGH TO ALLOW A FEW FLAKES
TO MIX IN WITH THE RAIN THIS MORNING FOR NORTHERN PORTIONS OF THE
FORECAST AREA. WITH THAT BEING SAID...ANY SNOW/MIX PRECIP REPORTS SO
FAR HAVE BEEN CONFINED TO NORTHERN PORTIONS OF INDIANA/ILLINOIS IN
CLOSE PROXIMITY TO DEFORMATION BAND THROUGH THE MID LEVELS. LEAVING
ANY MIX OF RA/SN MENTION OUT OF THE FORECAST OVER NORTHERN COUNTIES
THIS MORNING AS CONFIDENCE REMAINS LOW IN THIS OCCURRING AT THIS
TIME. WILL CONTINUE TO MONITOR OBSERVATIONS CLOSELY AND ADJUST AS
NECESSARY.
MOST RECENT SHORT RANGE MODEL GUIDANCE FROM THE HRRR AND RUC BOTH
BRINGING AREA OF STEADIER RAINFALL CURRENTLY ACROSS ILLINOIS THROUGH
THE FORECAST AREA THIS MORNING. DEEPER MOISTURE AND STRONGER FORCING
SHIFTS EAST BY EARLY AFTERNOON WITH RAINFALL INTENSITY EXPECTED TO
DROP OFF TO JUST LIGHT RAIN OR DRIZZLE AS THE LOWEST 8-10KFT REMAIN
SATURATED. WILL CARRY CATEGORICAL POPS THIS MORNING...DROPPING POPS
BACK FOR THE AFTERNOON AS DRIER AIR ALOFT STEADILY PRESSES INTO THE
REGION FROM THE SOUTHWEST. E/NE WINDS AT 10-15MPH WITH A FEW GUSTS
TO AROUND 20 MPH FOR MUCH OF THE DAY WILL MAKE FOR RAW CHILLY
CONDITIONS.
TEMPS...TRICKY SETUP FOR TEMPS TODAY AS MOST LOCATIONS ARE LIKELY TO
EXPERIENCE HIGHS SHORTLY AFTER DAYBREAK. COMBINATION OF THICK
STRATUS DECK...PRECIPITATION AND STEADY EAST/NORTHEAST FLOW IN THE
LOW LEVELS DOES NOT APPEAR CONDUCIVE AT ALL TO MUCH OF A RISE IN
TEMPS LATER TODAY. 850MB TEMPS DO WARM A BIT INTO THE AFTERNOON AND
THAT MAY BE GOOD FOR A BUMP IN TEMPS OF A COUPLE DEGREES ONCE THE
STEADIER RAIN SHIFTS EAST. NORTHERN COUNTIES MAY REMAIN IN THE 30S
ALL DAY.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
FORECAST CHALLENGES IN THE SHORT TERM FOCUS ON ENDING OF THE PRECIP
THIS EVENING AND TEMPS THEREAFTER AS HIGH PRESSURE EXPANDS INTO THE
REGION.
MODELS CONTINUE TO FAVOR A FASTER ENDING TO PRECIP LATE TONIGHT.
UPPER LOW REMAINS BEHIND WITH LITTLE MOISTURE AND FORCING TO WORK
WITH AS THE SURFACE WAVE MOVES QUICKLY EAST INTO THE CENTRAL
APPALACHIANS. DRIER AIR AND SUBSIDENCE WITH HIGH PRESSURE RIDGE OVER
THE WESTERN GREAT LAKES ADVECT SOUTH LATE TONIGHT AND SERVE TO
OVERWHELM ANY REMAINING LOW LEVEL MOISTURE. WITH LACK OF ANY
SIGNIFICANT FORCING...ANTICIPATE LIGHT RAIN/DRIZZLE WILL END FROM
NORTH TO SOUTH FROM LATE EVENING INTO THE OVERNIGHT. AREAS NORTH OF
I-70 SHOULD BE MAINLY DRY FROM MIDNIGHT ON WITH PRECIP ENDING AT
LOCATIONS FURTHER SOUTH PRIOR TO DAYBREAK SUNDAY. BOUNDARY LAYER
WILL BEGIN COOLING DURING THE EVENING BUT DEEPER MOISTURE AND MOST
IF NOT ALL PRECIP SHOULD BE FINISHED BEFORE CONDITIONS BECOME
SUPPORTIVE FOR LIGHT SNOW TO MIX IN. WHILE A FEW FLAKES ARE
CERTAINLY NOT OUT OF THE QUESTION...CHANCES APPEAR SO LOW TO KEEP
ANY MENTION OUT OF THE FORECAST AT THIS TIME. MODEL SOUNDINGS ALSO
SHOW RAPID DRYING INTO THE LOW LEVELS LATE TONIGHT WITH NORTHERN
COUNTIES LIKELY TO CLEAR PRIOR TO DAYBREAK.
DESPITE THE REMNANT UPPER LEVEL FEATURE DRIFTING THROUGH THE LOWER
OHIO VALLEY THROUGH SUNDAY NIGHT...PRESENCE OF DEEP SUBSIDENCE AND
DRY AIR ASSOCIATED WITH THE BROAD HIGH PRESSURE RIDGE WILL PROVIDE
TRANQUIL WEATHER FOR THE REMAINDER OF THE PERIOD THROUGH MONDAY
NIGHT. ANY LINGERING CLOUDS SUNDAY MORNING WILL QUICKLY BE PUSHED
OFF TO THE SOUTH AS DRIER AIR FULLY TAKES HOLD OVER CENTRAL INDIANA.
MODEL SOUNDINGS SHOW ABUNDANCE OF SUBSIDENT AIR AND RESULT SHOULD BE
MAINLY SUNNY SKIES FOR SUNDAY WITH LIGHT NORTHERLY FLOW. MAINLY
CLEAR SKIES WILL CONTINUE SUNDAY NIGHT AND INTO MONDAY AS THE HIGH
PRESSURE RIDGE REMAINS THE DOMINANT WEATHER FEATURE OVER THE REGION.
MAY SEE A FEW CLOUDS MONDAY NIGHT AS A WEAK DISTURBANCE ALOFT MOVES
INTO THE GREAT LAKES.
TEMPS...MOS GUIDANCE LOOKED QUITE REASONABLE THROUGH THE PERIOD AS
HIGH TEMPS RECOVER INTO THE MID AND UPPER 40S FOR MUCH OF THE
FORECAST AREA ON BOTH SUNDAY AND MONDAY. LEANED TOWARDS COOLER
MAVMOS SUNDAY NIGHT WITH CLEAR SKIES AND LIGHT NORTHERLY FLOW.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
THE MAIN CONCERN DURING THE PERIOD IS PRECIPITATION CHANCES
ASSOCIATED WITH SEVERAL UPPER WAVES PASSING THROUGH THE FORECAST
AREA.
ALL MODELS BRIEFLY SHOW WEAK UPPER LEVEL RIDGING EARLY TUESDAY WHICH
WILL KEEP CONDITIONS DRY. HOWEVER...CLOUD COVER LOOKS TO INCREASE
THROUGHOUT THE DAY AS THE RIDGE BEGINS TO FLATTEN PRIOR TO THE
ARRIVAL OF THE FIRST WAVE. THIS WILL HAVE AN IMPACT ON TEMPERATURES
WITH READINGS EXPECTED TO BE NOT QUITE AS HIGH AS MONDAY...ALTHOUGH
STILL ABOVE AVERAGE.
ALL MODELS DEPICT AN UPPER LEVEL WAVE PASSING THROUGH ON WEDNESDAY
WITH THE GFS AND CANADIAN IN GOOD AGREEMENT WITH REGARDS TO TIMING
WHILE THE ECMWF IS MUCH SLOWER. WENT WITH SLIGHT CHANCE POPS FOR
WEDNESDAY AND EARLY THURSDAY TO ACCOUNT FOR THE SLOWER ECMWF
SOLUTION. ALLBLEND INITIALIZATION APPEARS TO HAVE A GOOD HANDLE ON
THIS COMPROMISE. PRECIPITATION TYPE COULD ALSO BE A CONCERN WITH
THICKNESS VALUES POSSIBLY BELOW 530 DM. THEREFORE...WENT WITH A
RAIN/SNOW MIX FOR WEDNESDAY BEFORE TRANSITIONING TO ALL SNOW HEADING
INTO THURSDAY.
A STRONG UPPER LOW LOOKS TO DEVELOP NEAR HUDSON BAY BY LATE IN THE
PERIOD. THIS SYSTEM COULD EJECT A FEW MORE WAVES ACROSS THE FORECAST
AREA LATE IN THE WORK WEEK AND INTO THE WEEKEND BUT WILL STICK WITH
A DRY FORECAST UNTIL THE MODELS HAVE A BETTER HANDLE ON THE TIMING
OF ANY WAVES.
&&
.AVIATION /DISCUSSION FOR THE 040900Z KIND TAF UPDATE/...
SHORT TERM MODEL DATA SUGGEST LIFT WILL INCREASE OVER THE NEXT FEW
HOURS...SO EXPECTING RAIN TO INCREASE IN INTENSITY/COVERAGE AS
SUNRISE APPROACHES. HEAVIER PRECIPITATION SHOULD RESULT IN THE
DEVELOPMENT OF MVFR VISIBILITY RESTRICTIONS/CEILINGS TOWARDS
SUNRISE. IFR CEILINGS STILL LOOK PROBABLE BY MID MORNING. NO
SIGNIFICANT CHANGES TO THE FORECAST AT THIS TIME.
SHORT TERM MODEL DATA ALSO SUGGEST INCREASING POTENTIAL FOR SOME
SURFACE WIND GUSTS AROUND 20KTS DEVELOPING BY MID MORNING FROM
070-090 HEADINGS. STARTING TO SEE EVIDENCE OF THIS OVER ILLINOIS.
MAY ADD SOME GUSTS TO THE FORECAST AT A LATER TIME IF THINGS TREND
IN THAT DIRECTION. PREVIOUS DISCUSSION FOLLOWS.
CONDITIONS WILL LOWER OVERNIGHT INTO SATURDAY AS RAIN DEVELOPS FROM
THE SOUTH AND WEST. EXPECT MVFR CEILINGS AND VISIBILITIES BY 12Z.
DURING MORNING WIDESPREAD IFR AND LOCAL LIFR CEILINGS WILL
DEVELOP. VISIBILITIES MOSTLY MVFR WITH LOCAL IFR SATURDAY.
MAIN FORECAST QUESTION IS TIMING OF THIS. TAFS WILL PROBABLY HAVE
TO BE REVISED SEVERAL TIMES AS MORE INFORMATION BECOMES AVAILABLE.
WINDS MOSTLY EAST 10-15 KNOTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....HOMANN/RYAN
AVIATION...JK/JAS
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
537 PM CST SUN FEB 5 2012
.AVIATION...
LARGE AREA OF IFR/LIFR STRATUS AND LIGHT FOG REMAINS UNDER LOW LEVEL
INVERSION OF WEAK SURFACE HIGH PRESSURE OVER MOST OF IOWA. TRENDS
SUPPORTS CLOUD BASES OF 300 TO 900 FEET ALL TERMINALS TONIGHT AND
VISIBILITIES OF 3 TO 6 MILES DECREASING TO 1 TO 3 MILES AFTER
MIDNIGHT. WESTERLY AND SOUTHWESTERLY WINDS TO BRING IN MIXING AND
DRIER AIR ACROSS ALL TERMINALS WITH CLEARING SKIES AND 7 MILES FOR
VFR CONDITIONS BETWEEN 15-18Z. VFR CONDITIONS TO CONTINUE AT LEAST
THROUGH 07/06Z. ..NICHOLS..
&&
.PREV DISCUSSION... /ISSUED 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 TECHNIQUES 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..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS DES MOINES IA
341 PM CST SAT FEB 4 2012
.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...04/18Z
MAIN CONCERNS AT MIDDAY ARE OBVIOUSLY SNOW TRENDS...BUT ALSO LARGE
AREA OF LIFR STRATUS UPSTREAM ACROSS SD AND MN. MODEL TRENDS
SUGGEST LITTLE CHANGE WITH REGARD TO THE SNOW WITH PERSISTENT LIFR
AT KDSM AND IFR AT KOTM UNTIL LATE AFTERNOON WHEN CONDITIONS ARE
EXPECTED TO IMPROVE. NEXT CONCERN BECOMES FATE OF SD/MN LOW CLOUDS
AND FOG. SATELLITE TRENDS INDICATE THAT IT IS SLOWLY ADVANCING
SOUTHWARD AND HAVE BROUGHT LIFR/IFR INTO KFOD/KMCW/KALO 22Z-06Z.
POTENTIAL IS CERTAINLY THERE FARTHER SOUTH /KDSM/KOTM/ BUT
CONFIDENCE IS NOT THERE YET SO HAVE ONLY INTRODUCED RADIATION FOG
AND MVFR/LIFR VSBYS.
&&
.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...SMALL
AREA FORECAST DISCUSSION
NWS DES MOINES IA
146 PM CST SAT FEB 4 2012
.UPDATE...
HAVE MADE SOME HEADLINE ADJUSTMENTS WITH AFTERNOON UPDATE BASED ON
CURRENT TRENDS. SNOW DID NOT ADVANCE AS FAR NORTH AS ANTICIPATED SO
HIGHWAY 30 TIER OF WARNINGS AND ADVISORIES HAS BEEN CANCELLED. WEST
TO EAST ORIENTED AXIS OF HEAVIER AMOUNTS HAS EXTENDED TOWARD
GRINNELL AND OSKALOOSA AREAS HOWEVER SO ADVISORY HAS BEEN EXPANDED
INTO THOSE AREAS. VARIOUS WRF RUNS...ALONG WITH HRRR AND RAPID
REFRESH MODELS...ALL SUGGEST PRECIP SHOULD END THIS EVENING SO HAVE
ENDED ALL HEADLINES AT 06Z RATHER THAN 12Z. DO NOT EXPECT MUCH
BLOWING OR DRIFTING OVERNIGHT DUE TO HEAVY WET NATURE OF THE SNOW.
JUST RECEIVED AN ISOLATED REPORT OF 11.5 INCHES NEAR
CUMBERLAND...ALTHOUGH GENERAL SNOW TOTALS ARE STILL EXPECTED TO VARY
FROM 5 TO 10 INCHES IN THE WARNING.
&&
.SHORT TERM /TODAY/...
POWERFUL WINTER STORM CURRENTLY ONGOING OVER SOUTHEAST NEBRASKA INTO
SOUTHWEST IA. LARGE UPPER LOW IS GRADUALLY SHIFTING EAST ACROSS
NEBRASKA AND KANSAS THIS MORNING. THE STRONGEST PV ANOMALY
ASSOCIATED WITH THE SYSTEM IS LIFTING TOWARD SOUTHEAST
NEBRASKA...WHERE CONVECTIVE SNOW HAS BEEN ONGOING FOR THE PAST
SEVERAL HOURS. CONVECTIVE ELEMENTS ALSO CURRENTLY LIFTING NORTH OUT
OF MISSOURI AND INTO SOUTH CENTRAL IOWA. MID LEVEL LAPSE RATES ABOVE
700 MB BECOME RELATIVELY STEEP AS THE PV ANOMALY AND ATTENDANT MID
LEVEL THETA-E ADVECTION LIFT NORTHEAST INTO CENTRAL IA AND LOWER THE
STATIC STABILITY AND INCREASE MUCAPES TO AROUND 100 J/KG. THEREFORE
CAN NOT RULE OUT A PERIOD OF THUNDER SNOW THIS MORNING.
THE PRIMARY CHALLENGE WITH THE SYSTEM IS ESTABLISHING THE NORTHWARD
EXTENT OF THE PRECIPITATION WITH DRY AIR ADVECTING SOUTHWARD THROUGH
NORTHERN IOWA FROM THE DAKOTAS HIGH PRESSURE. TIME HEIGHT CROSS
SECTIONS HAVE BEEN CONSISTENT SINCE THE 00Z FEB 3 RUNS OF PLACING
THE STRONGEST FORCING THIS MORNING SOMEWHERE BETWEEN THE HIGHWAY 30
AND INTERSTATE 80 CORRIDORS AND JUST NORTH OF WHERE THE MODEL ENDS
PRECIPITATION. THIS IS A TYPICAL BIAS IN MODELS WITH SUCH SITUATIONS
WHERE THE MODELS GIVE MORE WEIGHT TO THE INITIAL LOW LEVEL DRY AIR
DESPITE VERY STRONG DYNAMICS THAT TYPICALLY CAN PRECIP LOAD THIS
REGION FOR A SUSTAINED PERIOD. WITH PWAT VALUES NEARLY 200 PERCENT
ABOVE SEASONAL VALUES...SUFFICIENT MOISTURE IS IN PLACE TODAY FOR
HEAVY SNOWFALL AMOUNTS. STILL VERY POSSIBLE TO HAVE A NARROW BAND OF
HEAVY SNOW THROUGH CENTRAL IA NEAR OR JUST NORTH OF DES MOINES THEN
FANNING AND WIDENING TO THE SOUTHWEST. SHOULD HAVE A PERIOD OF GUSTY
NORTHEAST WINDS AND WILL CREATE SOME BLOWING SNOW...THAT HAS BEEN
ADDED. HEADLINES REMAIN THE SAME...POSSIBLE SOME MINOR ADJUSTMENTS
AND ADDITIONS MAY BE REQUIRED ON THE EDGES.
.LONG TERM /TONIGHT THROUGH FRIDAY/...
SYSTEM TO IMPACT THE AREA TODAY...WILL CONTINUE TO WEAKEN TONIGHT AS
IT DROPS SOUTHEASTWARD INTO MISSOURI. THIS SHOULD ALLOW ANY
LINGERING PRECIPITATION TO TAPER OFF FROM NORTH TO SOUTH EARLY THIS
EVENING...WITH MAYBE A BIT OF LIGHT SNOW STILL LINGERING ALONG THE
IA/MO BORDER THROUGHOUT THE EARLY MORNING HOURS. MAJORITY OF
ACCUMULATING PRECIPITATION SHOULD BE DONE BY EARLY EVENING...WITH
AROUND A FEW TENTHS TO ANOTHER HALF INCH OF SNOW POSSIBLE ACROSS THE
SOUTHWESTERN CWA THIS EVENING. OTHERWISE EXPECT CLOUDS TO CLEAR
QUITE RAPIDLY LATE TONIGHT. HOWEVER LARGE AREA OF STRATUS SITUATED
TO THE NORTH/NORTHWEST OF THE CWA ATTM...SO SOMEWHAT CONCERNED COULD
HAVE SOME LOW CLOUDS LINGER LATE TONIGHT. FOR NOW MODELS SEEM NOT
PICKING UP ON IT...SO DID KEEP CLOUD COVER UP A BIT LATE
TONIGHT...JUST IN CASE LOW STRATUS LINGERS. OTHERWISE QUIET FORECAST
EXPECTED FOR MAJORITY OF MID/LONG RANGE WITH DRY CONDITIONS EXPECTED
THROUGH MONDAY NIGHT...BENEATH SPLIT-FLOW REGIME AND SOUTHERN STREAM
UPPER LEVEL RIDGING. GFS/EC ADVERTISE ANOTHER TROUGH DIGGING INTO
THE INTERMOUNTAIN WEST BY LATER MONDAY...AND PUSH IT EASTWARD
TUESDAY INTO WEDNESDAY. THIS COULD BRING SOME LIGHT PRECIPITATION TO
THE SOUTHERN CWA TUESDAY INTO TUESDAY NIGHT...BEFORE THE SYSTEM
SHOVES INTO THE OHIO VALLEY REGION WEDNESDAY. LATEST GUIDANCE
SUGGEST ONLY POPS ACROSS THE FAR SOUTHERN CWA...SO HAVE CONFINED
POPS TO THAT AREA FOR THE TIMEFRAME...WITH INCREASED CLOUD COVER
ACROSS REMAINDER OF CWA. OTHERWISE LARGE UPPER LEVEL TROUGH TO DIG
INTO THE CENTRAL/EASTERN US FOR FRIDAY AND BEYOND...SUGGESTING
A PUSH OF ARCTIC AIR SOUTH. THIS WOULD SEND H85 TEMPS INTO THE
TEENS BELOW ZERO CELSIUS...AND WILL SEND MAX/MINS BELOW AVERAGE FOR
THE END OF THE FORECAST PERIOD AND JUST BEYOND.
&&
.AVIATION...04/18Z
MAIN CONCERNS AT MIDDAY ARE OBVIOUSLY SNOW TRENDS...BUT ALSO LARGE
AREA OF LIFR STRATUS UPSTREAM ACROSS SD AND MN. MODEL TRENDS
SUGGEST LITTLE CHANGE WITH REGARD TO THE SNOW WITH PERSISTENT LIFR
AT KDSM AND IFR AT KOTM UNTIL LATE AFTERNOON WHEN CONDITIONS ARE
EXPECTED TO IMPROVE. NEXT CONCERN BECOMES FATE OF SD/MN LOW CLOUDS
AND FOG. SATELLITE TRENDS INDICATE THAT IT IS SLOWLY ADVANCING
SOUTHWARD AND HAVE BROUGHT LIFR/IFR INTO KFOD/KMCW/KALO 22Z-06Z.
POTENTIAL IS CERTAINLY THERE FARTHER SOUTH /KDSM/KOTM/ BUT
CONFIDENCE IS NOT THERE YET SO HAVE ONLY INTRODUCED RADIATION FOG
AND MVFR/LIFR VSBYS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING REMAINS IN EFFECT UNTIL 06Z
AUDUBON-GUTHRIE-DALLAS-POLK-CASS-ADAIR-MADISON-ADAMS-UNION-
WINTER WEATHER ADVISORY UNTIL 06Z
CLARKE-DECATUR-JASPER-LUCAS-MARION-RINGGOLD-TAYLOR-WARREN-POWESHIEK-
MAHASKA-
&&
$$
UPDATE/AVIATION...SMALL
SHORT TERM...DONAVON
LONG TERM...BEERENDS
AREA FORECAST DISCUSSION
NWS TOPEKA KS
308 PM CST SAT FEB 4 2012
.DISCUSSION...
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
&&
.AVIATION...
EXPECT LOW CIGS TO REMAIN THROUGH AT LEAST MIDNIGHT. EXPECT OFF
AND ON DRIZZLE TO REMAIN AT KTOP AND KFOE THROUGH AT LEAST
22Z...WITH LIMITED VISIBILITY BEING THE PRIMARY THREAT. SOME LIGHT
SNOW MAY COMMENCE LATER THIS EVENING AS THE MAIN STORM SYSTEM
MOVES OFF TO THE EAST. LOWERED VISIBILITY DUE TO THE LIGHT SNOW IS
POSSIBLE...MAINLY AFTER 00Z. EXPECT CONDITIONS TO GRADUALLY
IMPROVE SHORTLY AFTER MIDNIGHT.
JL
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR KSZ010.
WINTER WEATHER ADVISORY UNTIL 9 PM CST THIS EVENING FOR KSZ008-
009-020.
&&
$$
AREA FORECAST DISCUSSION
NWS GOODLAND KS
1013 AM MST SAT FEB 4 2012
.DISCUSSION...
331 AM MST SAT FEB 4 2012
EARLY MORNING ANALYSIS OF RADAR TRENDS/WV IMAGERY/OBS INDICATED
BAND OF LIGHT TO MODERATE SNOW CONTINUED ACROSS THE NORTHERN HALF
OF THE FORECAST AREA WITH MODERATE ACCUMULATIONS HAVING BEEN
REPORTED OVER BOTH THE WESTERN AND EASTERN FRINGES WHILE THE
MIDDLE PORTION OF THE FORECAST AREA GENERALLY RECEIVED MUCH
LIGHTER ACCUMULATIONS. WILL BE MODIFYING ONGOING HIGHLIGHTS TO
REFLECT EXPECTED IMPACTS DURING THE DAY TODAY. HAVE ADJUSTED THE
WINTER STORM WARNING TO THE EASTERN PORTION OF THE FORECAST AREA
WITH A WINTER WEATHER ADVISORY FOR PRIMARILY BLOWING SNOW OVER THE
WESTERN COUNTIES. THE EXCEPTIONS WILL THE FAR SOUTHERN KANSAS
COUNTIES AS WELL AS CHEYENNE COUNTY COLORADO WHERE LITTLE IF ANY
SNOW IS ANTICIPATED TODAY.
DO ANTICIPATE WINDS WILL STRENGTHEN A BIT TODAY AS THE AREA OF LOW
PRESSURE CONTINUES TO OCCLUDE. SIX-HOUR PRESSURE RISES OF 4 TO 5
MB WILL OCCUR OVER THE EASTERN PORTION WITH 3 TO 4 MB SIX-HOUR
PRESSURE RISES OVER THE WEST. AN ADDITIONAL 2 TO 3 INCHES OF SNOW
IS EXPECTED ACROSS THE EASTERN THIRD OF THE AREA BEFORE TAPERING
OFF DURING THE AFTERNOON HOURS. PERHAPS ANOTHER INCH OR SO WILL BE
POSSIBLE ALONG AND WEST OF HIGHWAY 25 AND NORTH OF HIGHWAY 40
WHERE THE WINTER WEATHER ADVISORY WILL CONTINUE.
TEMPS DURING THE DAY TODAY WILL HOLD IN THE LOW TO MID 30S WHICH
IS AROUND 10 DEGREES BELOW NORMAL. THE SKY WILL CLEAR OVERNIGHT
WITH NORTHWESTERLY WINDS DIMINISHING. FOR LOWS TONIGHT INTO
SUNDAY...TENDED TOWARD THE COLDEST GUIDANCE ESPECIALLY FOR THOSE
AREAS WHERE SNOW PACK WILL BE THE DEEPEST.
SNOW PACK WILL CONTINUE TO IMPACT AFTERNOON TEMPS THROUGH AT LEAST
MONDAY WITH READINGS LIKELY REMAINING IN THE MID 30S WHICH
LOCATIONS FURTHER SOUTH WILL SEE TEMPS WARMING INTO THE LOW TO MID
40S. -FOLTZ
TUESDAY THROUGH FRIDAY...LONG RANGE MODELS AGREE THAT A 500 MB LOW
WILL EJECT EAST OVER THE FORECAST AREA TUESDAY. HAVE CONTINUED A
SLIGHT CHANCE OF SNOW WITH THE SYSTEM DURING THE DAY. THE REST OF
THE FORECAST PERIOD WILL BE DOMINATED BY DRY NORTHWEST FLOW.
TEMPERATURES WILL BE BELOW NORMAL...ESPECIALLY OVER THE NORTHERN
THIRD WHERE RECENT SNOW COVER WILL HOLD DOWN TEMPERATURES THROUGH
THE FIRST HALF OF THE WEEK. THE BEST WARM AIR ADVECTION OCCURS
FRIDAY WHEN TEMPERATURES SHOULD REACH INTO THE 40S. -MENTZER
FOLTZ
&&
.AVIATION...
1002 AM MST SAT FEB 4 2012
MVFR TO VFR CONDITIONS ARE EXPECTED FOR THE 18Z TAFS. SNOWFALL AND
LOW CLOUDS WILL GRADUALLY COME TO AN END DURING THE MID TO LATE
AFTERNOON AS THE STORM SYSTEM MOVES NORTHEAST. MODELS HAVE KGLD
UNDER MVFR CEILINGS FOR THE ENTIRE AFTERNOON. HOWEVER OBSERVATIONS
NORTH OF THE SITE INDICATE VFR CEILINGS. THE HRRR MODEL SEEMED TO
HAVE THE BEST HANDLE ON THE CURRENT CEILINGS SO COMPROMISED
BETWEEN THAT AND THE OBSERVATIONS...BRINGING THE HIGHER CEILINGS
IN AROUND 21Z. FOR KMCK MVFR CEILINGS WILL LAST THROUGH THE
AFTERNOON. DURING THE EVENING VFR CEILINGS WILL MOVE IN. WITH THE
RECENT SNOWFALL AND TEMPERATURES COOLING TO NEAR THE DEW
POINT...FOG MAY FORM AT BOTH SITES. HOWEVER THE DEW POINTS WILL
FALL DURING THE NIGHT AS DRIER AIR MOVES IN...SO FOG MAY NOT BE AN
ISSUE.
JTL
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR KSZ002>004-
015-016-029.
WINTER WEATHER ADVISORY UNTIL 5 PM MST /6 PM CST/ THIS AFTERNOON
FOR KSZ001-013-014-027-028.
NE...WINTER STORM WARNING UNTIL 6 PM CST THIS EVENING FOR NEZ080-081.
WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR NEZ079.
CO...WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ090-
091.
&&
$$
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1244 PM EST SAT FEB 04 2012
...Updated Aviation Discussion...
...11 AM Forecast Update...
Updated the forecast to adjust POPs to the radar trends this
morning. There`s not much redevelopment behind this main line of
rain near Lexington as of 16Z, so continued to trend downward with
POPs for at least the early afternoon hours. The latest mesoscale
models still suggest the possibility of some redevelopment as the
sfc low over MO this morning pushes east into central KY this
evening. Therefore did keep 60-70% POPs for late this
afternoon/early evening. Still looks like areas of south central KY
could see a rumble of thunder but it would be very isld if any at
all. Went ahead and trended POPs down quicker after 0Z based on 12Z
NAM guidance. Looks like we`ll see mostly isld showers and drizzle
for tonight.
Made just a few tweaks to temps based on the gradient of temps that
has set up along the warm front over north central KY. Overall this
lowered highs for today by a degree or 2 for most locations.
6 AM Forecast Update...
A line of showers and embedded storms is racing out ahead of the
surface low and it`s associated cold front. Upstream 88D`s
indicating a clear back edge to this precip, so have changed the
forecast around to go for scattered showers/chance rain by around
Noon. With the upper low still well west of the region and that low
closing in, would not be surprised to see another round/line of
showers and storms developing later this afternoon and continuing
into the evening hours. So new PoP forecast goes for 100 percent
chance this morning then trends down to high-end chance, though that
may be generous given latest HRRR forecasts, in the early afternoon
then back again to the likely range over the west by late afternoon.
Did not change winds or temps/dewpoints other than to blend with
current obs. Updated products already out.
&&
.Short Term (Today and Tonight)...
1013 mb low over SW MO will shift east today along a stalled frontal
boundary that is draped over the area this morning. By this time
Sunday, the low should be along the SE KY/NE TN border. The upper
level feature, now over western KS, that was driving this low is not
moving much, according to the latest Water Vapor imagery. Models
have this feature drifting east, only reaching central MO by
daybreak Sunday. Have a nice line of thunderstorms in the warm
sector ahead of the surface low. This line looks to move along the
border with TN this morning. Have the area of thunderstorm chances
extended farther north, in case the warm sector invades farther
north through the day today and allows some of that thunder to the
southern half of the region. Still not expecting severe weather with
this line, but wind fields are a little stronger aloft than what we
had in the last set of models. Some of the storms across south
central KY could see gusty winds to 30-40 mph today. The GFS looks
to have a little better handle on some warm air over south KY in its
soundings, and even they keep LI`s positive over our area with no
surface-based CAPE. The lowest LI`s come in this evening as the low
crosses the area, so will keep in storm chances to 06Z.
Rainfall totals still do not look to be much of an issue. With
updated forecasts have average totals at less than an inch now.
These values are in line with SREF plumes for rainfall, as well as
HPC forecast through 12z Monday.
The temperature forecast today depends on how far the boundary
shifts north or south. For highs, have gone with a range from the
low 40s over the north to around 60 across the south. Similarly for
lows tonight, the southeast should stay warmest the longest, as the
low will just clear the area between midnight and daybreak. Thus
have a range from the mid 30s over the north to the mid/upper 40s
down south.
.Long Term (Sunday - Friday)...
Sunday - Sunday Night...
Surface low will move southeast to the Carolinas through Sunday with
a closed upper low hanging over the Ohio/Mississippi river
confluence. Expect a few isolated rain showers to linger behind
frontal boundary through Sunday, mainly south of the Ohio River.
Skies should begin to clear from north to south through the day with
highs ranging from the upper 40s to mid 50s across the south. By
Sunday evening, the closed upper low will work its way across the
area with limited moisture to work with. Therefore will continue to
keep Sunday night forecast dry with only a noted increase in low to
mid level clouds. Expect lows to drop right around the freezing mark
by dawn on Monday morning.
Monday - Tuesday...
A dry period of weather will continue into Monday and Tuesday as
surface high pressure and weak ridging aloft are in control. Look
for highs right around 50 under mostly clear to partly cloudy skies.
Lows on Monday night should drop right around the 30 degree mark
with the coolest spots into the upper 20s.
Tuesday Night - Wednesday...
Focus will shift to a shortwave moving from the southern plains to
the Tennessee Valley after midnight late Tuesday night/early
Wednesday. Models have come into better agreement with timing and
strength of this system with ECMWF recently trending toward the more
progressive and overall weaker solution suggested by GFS/GEM. Best
chances for precipitation will be from after midnight early
Wednesday through midday. Precipitation type may come into question
with the possibility of rain or snow, depending on exact timing of
system. Overall, QPF should range around a tenth of an inch or less
with progressive system and doubt that if any snow falls, ground
temps would be cool enough to support accumulation. Will continue to
monitor.
Wednesday Night - Friday...
Confidence is low beyond Wednesday as there is quite a bit of
uncertainty with regard to timing of shortwaves embedded in the
upper flow pattern, as well as the evolution of some degree of
troughing over the eastern CONUS. Will keep the forecast mainly dry
with only small chances for a rain shower across the southern CWA on
Friday if more amplified solution does not work out and southern
stream moisture is able to make it north. Otherwise, may have to
watch for potential for a significant cool down by the end of the
week into next weekend.
&&
.Aviation (18Z TAF Issuance)...
Complicated TAF forecast with several VSBY/CIG issues. These
problems are courtesy of a stalled sfc boundary over central KY and
an approaching sfc low which will move east into central KY this
evening, then SE to the Carolinas by Sun morning.
For BWG...CIGs have been troublesome with VFR CIGs being reported
out of BWG but a slew of CIGS around 1 kft are being reported at
nearby stations. Think that BWG CIGs will soon fall to around 1 kft
so will begin TAFs here with VCSH as well. Some showers and
possibly an isld t-storm are expected for this afternoon so will
continue the CB mention with MVFR conditions. Showers should taper
off this evening with lingering drizzle sticking around through the
overnight hours. CIGS look to go IFR around 2Z with VSBYs dropping
to IFR around 5Z. Conditions will begin to improve by mid morning.
For SDF...CIGs have already dropped to 600 ft this afternoon and
expect them to stay there. A few showers may redevelop by late
afternoon pushing VSBYs into the MVFR cat. After 2Z...expect CIGS
around 400 ft and patchy drizzle for much of the overnight hours
with MVFR VSBYs. Conditions should start to improve after 14Z.
For LEX...CIGs have started to decline and should reach 400 ft
shortly in light rain showers and IFR CIGs. While VSBYs are
expected to improve in about an hour after the rain shower moves
east, CIGS will likely stay around 400-600 ft for much of the
afternoon. A few showers may redevelop by late afternoon pushing
VSBYs into the MVFR cat. After 2Z...expect CIGS around 400 ft and
patchy drizzle for much of the overnight hours with IFR VSBYs.
Conditions should start to improve after 15Z.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......RJS
Long Term........BJS
Aviation.........AMS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
1118 AM EST SAT FEB 04 2012
...11 AM Forecast Update...
Updated the forecast to adjust POPs to the radar trends this
morning. There`s not much redevelopment behind this main line of
rain near Lexington as of 16Z, so continued to trend downward with
POPs for at least the early afternoon hours. The latest mesoscale
models still suggest the possibility of some redevelopment as the
sfc low over MO this morning pushes east into central KY this
evening. Therefore did keep 60-70% POPs for late this
afternoon/early evening. Still looks like areas of south central KY
could see a rumble of thunder but it would be very isld if any at
all. Went ahead and trended POPs down quicker after 0Z based on 12Z
NAM guidance. Looks like we`ll see mostly isld showers and drizzle
for tonight.
Made just a few tweaks to temps based on the gradient of temps that
has set up along the warm front over north central KY. Overall this
lowered highs for today by a degree or 2 for most locations.
6 AM Forecast Update...
A line of showers and embedded storms is racing out ahead of the
surface low and it`s associated cold front. Upstream 88D`s
indicating a clear back edge to this precip, so have changed the
forecast around to go for scattered showers/chance rain by around
Noon. With the upper low still well west of the region and that low
closing in, would not be surprised to see another round/line of
showers and storms developing later this afternoon and continuing
into the evening hours. So new PoP forecast goes for 100 percent
chance this morning then trends down to high-end chance, though that
may be generous given latest HRRR forecasts, in the early afternoon
then back again to the likely range over the west by late afternoon.
Did not change winds or temps/dewpoints other than to blend with
current obs. Updated products already out.
&&
.Short Term (Today and Tonight)...
1013 mb low over SW MO will shift east today along a stalled frontal
boundary that is draped over the area this morning. By this time
Sunday, the low should be along the SE KY/NE TN border. The upper
level feature, now over western KS, that was driving this low is not
moving much, according to the latest Water Vapor imagery. Models
have this feature drifting east, only reaching central MO by
daybreak Sunday. Have a nice line of thunderstorms in the warm
sector ahead of the surface low. This line looks to move along the
border with TN this morning. Have the area of thunderstorm chances
extended farther north, in case the warm sector invades farther
north through the day today and allows some of that thunder to the
southern half of the region. Still not expecting severe weather with
this line, but wind fields are a little stronger aloft than what we
had in the last set of models. Some of the storms across south
central KY could see gusty winds to 30-40 mph today. The GFS looks
to have a little better handle on some warm air over south KY in its
soundings, and even they keep LI`s positive over our area with no
surface-based CAPE. The lowest LI`s come in this evening as the low
crosses the area, so will keep in storm chances to 06Z.
Rainfall totals still do not look to be much of an issue. With
updated forecasts have average totals at less than an inch now.
These values are in line with SREF plumes for rainfall, as well as
HPC forecast through 12z Monday.
The temperature forecast today depends on how far the boundary
shifts north or south. For highs, have gone with a range from the
low 40s over the north to around 60 across the south. Similarly for
lows tonight, the southeast should stay warmest the longest, as the
low will just clear the area between midnight and daybreak. Thus
have a range from the mid 30s over the north to the mid/upper 40s
down south.
.Long Term (Sunday - Friday)...
Sunday - Sunday Night...
Surface low will move southeast to the Carolinas through Sunday with
a closed upper low hanging over the Ohio/Mississippi river
confluence. Expect a few isolated rain showers to linger behind
frontal boundary through Sunday, mainly south of the Ohio River.
Skies should begin to clear from north to south through the day with
highs ranging from the upper 40s to mid 50s across the south. By
Sunday evening, the closed upper low will work its way across the
area with limited moisture to work with. Therefore will continue to
keep Sunday night forecast dry with only a noted increase in low to
mid level clouds. Expect lows to drop right around the freezing mark
by dawn on Monday morning.
Monday - Tuesday...
A dry period of weather will continue into Monday and Tuesday as
surface high pressure and weak ridging aloft are in control. Look
for highs right around 50 under mostly clear to partly cloudy skies.
Lows on Monday night should drop right around the 30 degree mark
with the coolest spots into the upper 20s.
Tuesday Night - Wednesday...
Focus will shift to a shortwave moving from the southern plains to
the Tennessee Valley after midnight late Tuesday night/early
Wednesday. Models have come into better agreement with timing and
strength of this system with ECMWF recently trending toward the more
progressive and overall weaker solution suggested by GFS/GEM. Best
chances for precipitation will be from after midnight early
Wednesday through midday. Precipitation type may come into question
with the possibility of rain or snow, depending on exact timing of
system. Overall, QPF should range around a tenth of an inch or less
with progressive system and doubt that if any snow falls, ground
temps would be cool enough to support accumulation. Will continue to
monitor.
Wednesday Night - Friday...
Confidence is low beyond Wednesday as there is quite a bit of
uncertainty with regard to timing of shortwaves embedded in the
upper flow pattern, as well as the evolution of some degree of
troughing over the eastern CONUS. Will keep the forecast mainly dry
with only small chances for a rain shower across the southern CWA on
Friday if more amplified solution does not work out and southern
stream moisture is able to make it north. Otherwise, may have to
watch for potential for a significant cool down by the end of the
week into next weekend.
&&
.Aviation (12Z TAF Issuance)...
Line of rain heading towards the TAF sites this morning. KBWG may
see a strike of lightning, so have a CB group in for the morning.
Upstream radar indicates there should be a break in the line behind
the main rain. However, low cigs remain behind the line, so expect
IFR conditions for most of the period, after starting out MVFR early
this morning. Another round of showers/rains is forecast later this
afternoon and evening as low pressure tracks across the region.
Again may see a little thunder near KBWG so have a CB group there
late this aftn and into the evening. Will see winds switch around to
northwesterly behind the low, but low cigs should remain to the end
of the period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........AMS
Short Term.......RJS
Long Term........BJS
Aviation.........RJS
AREA FORECAST DISCUSSION
NWS LOUISVILLE KY
636 AM EST SAT FEB 04 2012
...Forecast and Aviation Update...
A line of showers and embedded storms is racing out ahead of the
surface low and it`s associated cold front. Upstream 88D`s
indicating a clear back edge to this precip, so have changed the
forecast around to go for scattered showers/chance rain by around
Noon. With the upper low still well west of the region and that low
closing in, would not be surprised to see another round/line of
showers and storms developing later this afternoon and continuing
into the evening hours. So new PoP forecast goes for 100 percent
chance this morning then trends down to high-end chance, though that
may be generous given latest HRRR forecasts, in the early afternoon
then back again to the likely range over the west by late afternoon.
Did not change winds or temps/dewpoints other than to blend with
current obs. Updated products already out.
&&
.Short Term (Today and Tonight)...
1013 mb low over SW MO will shift east today along a stalled frontal
boundary that is draped over the area this morning. By this time
Sunday, the low should be along the SE KY/NE TN border. The upper
level feature, now over western KS, that was driving this low is not
moving much, according to the latest Water Vapor imagery. Models
have this feature drifting east, only reaching central MO by
daybreak Sunday. Have a nice line of thunderstorms in the warm
sector ahead of the surface low. This line looks to move along the
border with TN this morning. Have the area of thunderstorm chances
extended farther north, in case the warm sector invades farther
north through the day today and allows some of that thunder to the
southern half of the region. Still not expecting severe weather with
this line, but wind fields are a little stronger aloft than what we
had in the last set of models. Some of the storms across south
central KY could see gusty winds to 30-40 mph today. The GFS looks
to have a little better handle on some warm air over south KY in its
soundings, and even they keep LI`s positive over our area with no
surface-based CAPE. The lowest LI`s come in this evening as the low
crosses the area, so will keep in storm chances to 06Z.
Rainfall totals still do not look to be much of an issue. With
updated forecasts have average totals at less than an inch now.
These values are in line with SREF plumes for rainfall, as well as
HPC forecast through 12z Monday.
The temperature forecast today depends on how far the boundary
shifts north or south. For highs, have gone with a range from the
low 40s over the north to around 60 across the south. Similarly for
lows tonight, the southeast should stay warmest the longest, as the
low will just clear the area between midnight and daybreak. Thus
have a range from the mid 30s over the north to the mid/upper 40s
down south.
.Long Term (Sunday - Friday)...
Sunday - Sunday Night...
Surface low will move southeast to the Carolinas through Sunday with
a closed upper low hanging over the Ohio/Mississippi river
confluence. Expect a few isolated rain showers to linger behind
frontal boundary through Sunday, mainly south of the Ohio River.
Skies should begin to clear from north to south through the day with
highs ranging from the upper 40s to mid 50s across the south. By
Sunday evening, the closed upper low will work its way across the
area with limited moisture to work with. Therefore will continue to
keep Sunday night forecast dry with only a noted increase in low to
mid level clouds. Expect lows to drop right around the freezing mark
by dawn on Monday morning.
Monday - Tuesday...
A dry period of weather will continue into Monday and Tuesday as
surface high pressure and weak ridging aloft are in control. Look
for highs right around 50 under mostly clear to partly cloudy skies.
Lows on Monday night should drop right around the 30 degree mark
with the coolest spots into the upper 20s.
Tuesday Night - Wednesday...
Focus will shift to a shortwave moving from the southern plains to
the Tennessee Valley after midnight late Tuesday night/early
Wednesday. Models have come into better agreement with timing and
strength of this system with ECMWF recently trending toward the more
progressive and overall weaker solution suggested by GFS/GEM. Best
chances for precipitation will be from after midnight early
Wednesday through midday. Precipitation type may come into question
with the possibility of rain or snow, depending on exact timing of
system. Overall, QPF should range around a tenth of an inch or less
with progressive system and doubt that if any snow falls, ground
temps would be cool enough to support accumulation. Will continue to
monitor.
Wednesday Night - Friday...
Confidence is low beyond Wednesday as there is quite a bit of
uncertainty with regard to timing of shortwaves embedded in the
upper flow pattern, as well as the evolution of some degree of
troughing over the eastern CONUS. Will keep the forecast mainly dry
with only small chances for a rain shower across the southern CWA on
Friday if more amplified solution does not work out and southern
stream moisture is able to make it north. Otherwise, may have to
watch for potential for a significant cool down by the end of the
week into next weekend.
&&
.Aviation (12Z TAF Issuance)...
Line of rain heading towards the TAF sites this morning. KBWG may
see a strike of lightning, so have a CB group in for the morning.
Upstream radar indicates there should be a break in the line behind
the main rain. However, low cigs remain behind the line, so expect
IFR conditions for most of the period, after starting out MVFR early
this morning. Another round of showers/rains is forecast later this
afternoon and evening as low pressure tracks across the region.
Again may see a little thunder near KBWG so have a CB group there
late this aftn and into the evening. Will see winds switch around to
northwesterly behind the low, but low cigs should remain to the end
of the period.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
KY...NONE.
$$
Update...........RJS
Short Term.......RJS
Long Term........BJS
Aviation.........RJS
AREA FORECAST DISCUSSION...UPDATED
NWS NEW ORLEANS LA
947 AM CST SAT FEB 4 2012
.UPDATE...
WATCHING THE QLCS MOVING EAST 22 KT ACROSS SW LOUISIANA. THIS LINE
WAS SHOWING SIGNS OF WEAKENING IS IT MOVES INTO A MOISTURE RICH
BUT LESS UNSTABLE AIRMASS DOWNSTREAM. THE WRF AND RUC MODELS
INDICATED THIS TREND AND IT APPEARS TO BE OCCURRING. WAS
CONSIDERING UPDATING POPS BUT WILL CONTINUE TO WATCH TRENDS
THROUGH NOON BEFORE ADJUSTING. TIMING STILL APPEARS TO BRING
SYSTEM TO KBTR AROUND 19Z.
&&
.SOUNDING DISCUSSION...
SOUNDING WENT OFF FINE AFTER OVERCOMING SOME GROUND EQUIPMENT
FREQUENCY ISSUES. PRECIPITABLE WATER 1.18 INCHES WHICH IS
CONSIDERABLY LOWER THAN PAST COUPLE OF RUNS. MINOR CAPPING IN THE
MID LEVELS ABLE TO BE OVERCOME WITH A 330K LIFT FROM SURFACE. CHAP
OUTPUT ON SOUNDING SHOWS A RICKS INDEX OF 71 WHICH IS NOT SEVERE
AND WIND GUST POTENTIAL OF ONLY 19KT. SOUNDING VIL OF 79 YIELDS
LIQUID WHILE A 87 VIL PRODUCES PEA SIZED HAIL...NOT A LIKELY
OUTCOME TODAY. WINDS SHOW SOME SHALLOW VEERING THORUGH ABOUT 1KFT
BEFORE BECOMING UNIDIRECTIONALLY SOUTH TO 4KFT...SW 20KT THROUGH
18KFT. PEAK WINDS 71KT AT 46KFT...WELL ABOVE TROP LEVEL AROUND
41KFT.
&&
.DECISION SUPPORT... /EXPERIMENTAL/
DSS CODE...YELLOW.
DEPLOYED...NONE.
ACTIVATION..NONE.
ACTIVITIES...STORM SURVEILLANCE FOR SQUALL LINE APPROACHING FROM
WEST.
DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED
WATCH/WARNING/ADVISORY ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED = FULL ENGAGEMENT FOR MODERATE TO HIGH RISK SVR AND/OR
DIRECT TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 75 52 62 40 / 60 70 20 20
BTR 78 53 65 45 / 60 60 20 20
ASD 74 58 68 46 / 40 60 30 20
MSY 75 58 68 48 / 40 60 30 20
GPT 72 56 68 49 / 40 60 30 20
PQL 73 57 68 47 / 40 60 30 20
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&
$$
24/RR
AREA FORECAST DISCUSSION
NWS GRAY ME
1109 AM EST SAT FEB 4 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY AND WILL HOLD
OVER THE AREA THROUGH SUNDAY. A COLD FRONT WILL APPROACH FROM THE
NORTHWEST ON MONDAY AND WILL CROSS THE REGION MONDAY NIGHT. HIGH
PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST TUESDAY THROUGH
WEDNESDAY...MOVING OFFSHORE BY WEDNESDAY EVENING. LOW PRESSURE
CROSSING SOUTHERN CANADA WILL SWING A TRAILING COLD FRONT TOWARD
THE AREA ON THURSDAY. THE COLD FRONT WILL FINALLY PUSH INTO NEW
ENGLAND BY FRIDAY MORNING FOLLOWED BY HIGH PRESSURE IN THE
AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
1606Z UPDATE...
MOST OF THE SNOW SHOWERS FROM EARLIER THIS MORNING HAVE DISSIPATED
OR MOVED OFFSHORE. A QUICK INCH OF SNOW FELL IN A FEW COMMUNITIES
WITH THE PASSAGE OF THE TROUGH. HAVE LOWERED POPS WITH IMPROVING
SKY CONDITIONS FOR THE REMAINDER OF THE DAY. HAVE NUDGED TEMPS
DOWNWARDS A DEGREE OR TWO AND ADJUSTED DEW POINTS BASED ON 16Z
OBSERVATIONS. WINDS WILL CONTINUE TO BE GUSTY FOR THE NEXT SEVERAL
HOURS WITH BORDERLINE SCA TYPE WINDS ON THE MARINE LAYER.
UPDATE...
HAVE UPDATED TO INCLUDE SNOW SHOWERS IN THE MORNING PTN OF THE
FORECAST. EVEN A FEW BRIEF SQUALLS CAN BE EXPECTED TO CROSS THE
REGION THROUGH THE EARLY AFTERNOON HOURS PER LATEST RADAR TRENDS
AND LOCAL OBSERVATIONS. UPPED POPS AND CLOUD FCST TO INTO THE
LIKELY AND CATEGORICAL RANGE ACROSS PTNS OF SW MAINE. RAN THE SNOW
TOTAL TOOL TO SHOW ABOUT 1" OR SNOW ACCUMULATION ACROSS PTNS OF
SOUTHERN MAINE. THIS IS IN LINE WITH THE LATEST HRRR MODEL RUN.
REST OF THE FCST WILL REMAIN UNCHANGED AT THIS TIME.
PREV DISC... HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY
BRINGING MOSTLY SUNNY SKIES AND SEASONABLE TEMPERATURES. FAIR
AMOUNT OF CLOUDS CURRENTLY OVER MUCH OF NEW HAMPSHIRE AND WESTERN
MAINE AS A WEAK COLD FRONT SAGS SOUTH THROUGH THE REGION. ALSO A
FEW SNOW SHOWERS SHOWING UP IN THE MOUNTAINS. EXPECT CLOUD COVER
TO QUICKLY DIMINISH DOWNWIND OF THE MOUNTAINS THROUGH THE EARLY
MORNING HOURS. FARTHER NORTH CLOUDS WILL HANG TOUGH IN THE
MOUNTAINS THROUGH THE MORNING BUT SKIES SHOULD BECOME AT LEAST
PARTLY SUNNY BY EARLY TO MID AFTERNOON. HIGH TEMPS WILL RANGE
THROUGH THE 20S IN THE NORTH AND IN THE LOWER TO MID 30S IN THE
SOUTH.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
HIGH PRESSURE WILL HOLD OVER THE REGION TONIGHT RESULTING IN MOSTLY
CLEAR AND COLD CONDITIONS. EXPECT LOWS NEAR ZERO IN THE NORTH AND
IN THE SINGLE NUMBERS AND LOWER TEENS IN THE SOUTH.
HIGH PRESSURE WILL HOLD OVER THE AREA ON SUNDAY BUT PASSING UPPER
TROUGH WILL BRING MORE IN THE WAY OF CLOUDINESS TO THE REGION.
WILL SEE MORNING SUN GIVING WAY TO VARIABLE CLOUDS DURING THE DAY
WITH THE MAJORITY OF MOISTURE IN THE MOUNTAINS WHERE THERE COULD
BE A LATE DAY FLURRY. WILL SEE SLIGHTLY COOLER TEMPS WITH LOWER TO
MID 20S IN THE NORTH AND UPPER 20S TO LOWER 30S IN THE SOUTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A PERIOD OF MOSTLY QUIET WX THRU THE LONG TERM. A WEAK UPR LVL TROF
SLIDES THRU ON NW FLOW SUNDAY NGT WITH WARMING FLOW AT SFC AND H8
FROM W SW ALONG WITH SOME INCREASING RH. THIS WILL BRING SOME CLOUDS
BUT NO MORE THAN SLGT CHC -SHSN TO THE N/MT ZONES. THE UPR LVL TROF
MOVES THRU FOR MONDAY AS THE WARMING TREND CONTINUES. THIS SHOULD
GIVE US THE NICEST DAY OF THE LONG TERM PERIOD WITH ABOVE NORMAL
TEMPS. HIGHS ON MONDAY IN THE 30S TO LOWER 40S.
A CD FNT MOVES THRU MONDAY NGT BEGINNING TO BRING IN COLDER CANADIAN
AIR. A SECOND CD FNT MOVES THRU TUESDAY WITH MUCH COLDER AIR MOVING
IN ON N NW WINDS. MODELS SHOW A GOOD SHOT OF COLD AIR WITH H8 TEMPS
OF MINUS 15C OR COLDER MOVING IN LATE TUESDAY INTO TUESDAY NGT WITH
SFC HIGH PRES MOVING IN TO DROP OFF WINDS, CLR SKIES AND ALLOW FOR
GOOD RADIATIONAL COOLING. COLDEST MIN TEMPS LIKELY TO BE TUESDAY NGT
WITH LOWS BELOW ZERO N AND IN THE SINGLE NUMBERS TO AROUND 10 ABOVE
S.
THE HIGH QUICKLY MOVES OFF TO THE E WEDNESDAY AS AN UPR LVL TROF
LIFTS NE INTO THE REGION. THIS SYSTEM MOVES THRU WEDNESDAY NGT BUT
HAS A WEAK SFC SYSTEM ASSOCIATED WITH IT WITH LIMITED WRM AIR
ADVECTION DESPITE QUITE A BIT OF MOISTURE MOVING IN. THIS WILL BRING
A CHC OF SHSN TO THE REGION BUT NOT LOOKING LIKE A SIGNIFICANT EVENT
AT THIS TIME...BUT CERTAINLY THE BEST CHC FOR ACCUMULATING SN DURING
THE LONG TERM FCST PERIOD.
THIS SYSTEM MOVES BY FOR THURSDAY BUT A BROAD SW FLOW DEVELOPS ALOFT
BRINGING IN SOME MILDER AIR AHEAD OF A STRONG CD FNT THAT WILL BE
PUSHING OUT OF CENTRAL CANADA. THIS CD FNT MOVES THRU THE REGION ON
FRIDAY WITH MUCH COLDER AIR TO FOLLOW. THE FNT MAY KICK OFF A FEW
-SHSN AS WELL.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SUNDAY
NGT AND MONDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /16Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TODAY THROUGH SUNDAY.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...WEAK SYSTEMS MAY
PRODUCE ISOLD TO SCT -SHSN MAINLY ACROSS THE N/MT AREAS DURING
THIS PERIOD WITH VFR CONDITIONS THE MOST LIKELY WITH MVFR PSBL
WITH ANY -SHSN.
&&
.MARINE...
SHORT TERM...EXPECT NORTHWESTERLY GRADIENT TO TIGHTEN UP SOMEWHAT
BEHIND THE FRONT TODAY. WILL LIKELY SEE A FEW GUSTS TO 25 KT IN
FAR EASTERN WATERS FOR A BRIEF PERIOD TODAY BUT NOT PLANNING ON
ANY HEADLINES ATTM.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...INCREASING SW FLOW
LIKELY TO CREATE SCA WINDS AND SEAS MONDAY INTO MONDAY NGT. CD NW
FLOW TUESDAY NGT MAY ALSO RESULT IN SCA WINDS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAY ME
911 AM EST SAT FEB 4 2012
.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY AND WILL HOLD
OVER THE AREA THROUGH SUNDAY. A COLD FRONT WILL APPROACH FROM THE
NORTHWEST ON MONDAY AND WILL CROSS THE REGION MONDAY NIGHT. HIGH
PRESSURE WILL GRADUALLY BUILD IN FROM THE WEST TUESDAY THROUGH
WEDNESDAY...MOVING OFFSHORE BY WEDNESDAY EVENING. LOW PRESSURE
CROSSING SOUTHERN CANADA WILL SWING A TRAILING COLD FRONT TOWARD
THE AREA ON THURSDAY. THE COLD FRONT WILL FINALLY PUSH INTO NEW
ENGLAND BY FRIDAY MORNING FOLLOWED BY HIGH PRESSURE IN THE
AFTERNOON.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATE...
HAVE UPDATED TO INCLUDE SNOW SHOWERS IN THE MORNING PTN OF THE
FORECAST. EVEN A FEW BRIEF SQUALLS CAN BE EXPECTED TO CROSS THE
REGION THROUGH THE EARLY AFTERNOON HOURS PER LATEST RADAR TRENDS
AND LOCAL OBSERVATIONS. UPPED POPS AND CLOUD FCST TO INTO THE
LIKELY AND CATEGORICAL RANGE ACROSS PTNS OF SW MAINE. RAN THE SNOW
TOTAL TOOL TO SHOW ABOUT 1" OR SNOW ACCUMULATION ACROSS PTNS OF
SOUTHERN MAINE. THIS IS IN LINE WITH THE LATEST HRRR MODEL RUN.
REST OF THE FCST WILL REMAIN UNCHANGED AT THIS TIME.
PREV DISC... HIGH PRESSURE WILL BUILD IN FROM THE WEST TODAY
BRINGING MOSTLY SUNNY SKIES AND SEASONABLE TEMPERATURES. FAIR
AMOUNT OF CLOUDS CURRENTLY OVER MUCH OF NEW HAMPSHIRE AND WESTERN
MAINE AS A WEAK COLD FRONT SAGS SOUTH THROUGH THE REGION. ALSO A
FEW SNOW SHOWERS SHOWING UP IN THE MOUNTAINS. EXPECT CLOUD COVER
TO QUICKLY DIMINISH DOWNWIND OF THE MOUNTAINS THROUGH THE EARLY
MORNING HOURS. FARTHER NORTH CLOUDS WILL HANG TOUGH IN THE
MOUNTAINS THROUGH THE MORNING BUT SKIES SHOULD BECOME AT LEAST
PARTLY SUNNY BY EARLY TO MID AFTERNOON. HIGH TEMPS WILL RANGE
THROUGH THE 20S IN THE NORTH AND IN THE LOWER TO MID 30S IN THE
SOUTH.
&&
.SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
HIGH PRESSURE WILL HOLD OVER THE REGION TONIGHT RESULTING IN MOSTLY
CLEAR AND COLD CONDITIONS. EXPECT LOWS NEAR ZERO IN THE NORTH AND
IN THE SINGLE NUMBERS AND LOWER TEENS IN THE SOUTH.
HIGH PRESSURE WILL HOLD OVER THE AREA ON SUNDAY BUT PASSING UPPER
TROUGH WILL BRING MORE IN THE WAY OF CLOUDINESS TO THE REGION.
WILL SEE MORNING SUN GIVING WAY TO VARIABLE CLOUDS DURING THE DAY
WITH THE MAJORITY OF MOISTURE IN THE MOUNTAINS WHERE THERE COULD
BE A LATE DAY FLURRY. WILL SEE SLIGHTLY COOLER TEMPS WITH LOWER TO
MID 20S IN THE NORTH AND UPPER 20S TO LOWER 30S IN THE SOUTH.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A PERIOD OF MOSTLY QUIET WX THRU THE LONG TERM. A WEAK UPR LVL TROF
SLIDES THRU ON NW FLOW SUNDAY NGT WITH WARMING FLOW AT SFC AND H8
FROM W SW ALONG WITH SOME INCREASING RH. THIS WILL BRING SOME CLOUDS
BUT NO MORE THAN SLGT CHC -SHSN TO THE N/MT ZONES. THE UPR LVL TROF
MOVES THRU FOR MONDAY AS THE WARMING TREND CONTINUES. THIS SHOULD
GIVE US THE NICEST DAY OF THE LONG TERM PERIOD WITH ABOVE NORMAL
TEMPS. HIGHS ON MONDAY IN THE 30S TO LOWER 40S.
A CD FNT MOVES THRU MONDAY NGT BEGINNING TO BRING IN COLDER CANADIAN
AIR. A SECOND CD FNT MOVES THRU TUESDAY WITH MUCH COLDER AIR MOVING
IN ON N NW WINDS. MODELS SHOW A GOOD SHOT OF COLD AIR WITH H8 TEMPS
OF MINUS 15C OR COLDER MOVING IN LATE TUESDAY INTO TUESDAY NGT WITH
SFC HIGH PRES MOVING IN TO DROP OFF WINDS, CLR SKIES AND ALLOW FOR
GOOD RADIATIONAL COOLING. COLDEST MIN TEMPS LIKELY TO BE TUESDAY NGT
WITH LOWS BELOW ZERO N AND IN THE SINGLE NUMBERS TO AROUND 10 ABOVE
S.
THE HIGH QUICKLY MOVES OFF TO THE E WEDNESDAY AS AN UPR LVL TROF
LIFTS NE INTO THE REGION. THIS SYSTEM MOVES THRU WEDNESDAY NGT BUT
HAS A WEAK SFC SYSTEM ASSOCIATED WITH IT WITH LIMITED WRM AIR
ADVECTION DESPITE QUITE A BIT OF MOISTURE MOVING IN. THIS WILL BRING
A CHC OF SHSN TO THE REGION BUT NOT LOOKING LIKE A SIGNIFICANT EVENT
AT THIS TIME...BUT CERTAINLY THE BEST CHC FOR ACCUMULATING SN DURING
THE LONG TERM FCST PERIOD.
THIS SYSTEM MOVES BY FOR THURSDAY BUT A BROAD SW FLOW DEVELOPS ALOFT
BRINGING IN SOME MILDER AIR AHEAD OF A STRONG CD FNT THAT WILL BE
PUSHING OUT OF CENTRAL CANADA. THIS CD FNT MOVES THRU THE REGION ON
FRIDAY WITH MUCH COLDER AIR TO FOLLOW. THE FNT MAY KICK OFF A FEW
-SHSN AS WELL.
GENERALLY USED GFS40...HPC QPF AND BLEND OF MAV/MET MOS FOR SUNDAY
NGT AND MONDAY. USED GMOS FOR REST OF THE LONG TERM FCST... EXCEPT
USED A BLEND OF GFS40 AND MEX MOS GUIDANCE FOR MAX AND MIN TEMPS.
&&
.AVIATION /14Z SATURDAY THROUGH WEDNESDAY/...
SHORT TERM...VFR TODAY THROUGH SUNDAY.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...WEAK SYSTEMS MAY
PRODUCE ISOLD TO SCT -SHSN MAINLY ACROSS THE N/MT AREAS DURING
THIS PERIOD WITH VFR CONDITIONS THE MOST LIKELY WITH MVFR PSBL
WITH ANY -SHSN.
&&
.MARINE...
SHORT TERM...EXPECT NORTHWESTERLY GRADIENT TO TIGHTEN UP SOMEWHAT
BEHIND THE FRONT TODAY. WILL LIKELY SEE A FEW GUSTS TO 25 KT IN
FAR EASTERN WATERS FOR A BRIEF PERIOD TODAY BUT NOT PLANNING ON
ANY HEADLINES ATTM.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...INCREASING SW FLOW
LIKELY TO CREATE SCA WINDS AND SEAS MONDAY INTO MONDAY NGT. CD NW
FLOW TUESDAY NGT MAY ALSO RESULT IN SCA WINDS.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
640 PM EST SUN FEB 5 2012
LATEST UPDATE...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...(640 PM EST SUN FEB 5 2012)
A DIMINISHING BAND OF MVFR CLOUDS WAS COMING ASHORE NEAR KMKG AND
KBIV. THIS FEATURE IS LIKELY TO CROSS THE TAF SITES AS IT HEADS
EAST OVER THE NEXT COUPLE OF HOURS. THEN CLEARING AND RADIATIONAL
COOLING. THEN A LARGE AREA OF MVFR CLOUDS WILL ARRIVE FROM THE WEST
AFTER MIDNIGHT AND PERSIST INTO THE MORNING. FOG MAY DEVELOP AS
WELL PRIOR TO THE SECONDARY CLOUD DECKS ARRIVAL. WITH SOME
WIND...THIS RISK IS TOO LOW TO ADD AT THIS POINT.
&&
.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: MJS
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1250 PM EST SAT FEB 4 2012
UPDATED AVIATION DISCUSSION FOR THE 18Z TAFS
.SYNOPSIS... ISSUED AT 401 AM EST
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER WRN CAN AND TROF OVER QUEBEC. THIS
NW FLOW ALF IS KEEPING THE CLOSED LO RESPONSIBLE FOR HEAVY SN IN
COLORADO WELL TO THE SW OF THE UPR LKS...AND THIS WL REMAIN THE CASE
THRU THE WEEKEND. ALTHOUGH A NW FLOW ALF IS OFTEN ASSOCIATED WITH
VERY COLD AIR THIS TIME OF YEAR...THE AIRMASS OVER W AND CNTRL CAN
AS WELL AS THE NRN TIER OF THE CONUS IS PACIFIC IN ORIGIN. 00Z H85
TEMPS RANGE FM -4C AT APX/YPL TO -3C AT INL AND -2C AT GRB. AT THE
PAS NEAR LK WINNIPEG IN MANITOBA...THE 00Z H85 TEMP WAS 0C. COLDER
AIR IS PRESENT TO THE NE TOWARD THE VORTEX IN QUEBEC...BUT EVEN
THERE THE 00Z H85 TEMP WAS JUST -15C AT MOOSONEE AT THE S END OF
JAMES BAY. SINCE THE CWA IS NEAR THE CONFLUENCE ZN BTWN THE
PREVAILING NW FLOW ALF AND A SLY FLOW TO THE E OF THE CUTOFF LO IN
THE PLAINS...A SFC HI PRES RDG IS PRESENT FM MN ESEWD INTO LOWER MI.
LOCAL 00Z RAOBS SHOW A SHARP INVRN BTWN H85-95 ASSOCIATED WITH LARGE
SCALE SUBSIDENCE. TEMPS OVER THE CWA HAVE FALLEN SHARPLY EARLY THIS
MRNG TOWARD 10 ABOVE...ESPECIALLY OVER THE INTERIOR W UNDER THE
ACCOMPANYING MOCLR SKIES. BUT THERE IS QUITE A BIT OF LO CLD
STRETCHING FM ERN UPR MI N AND NWWD INTO ONTARIO WITH MSTR TRAPPED
BLO INVRN ALONG A SFC TROF ASSOCIATED WITH A SHRTWV DIGGING SEWD IN
THE NW FLOW ALF. ACCOMPANYING PCPN COVERAGE APPEARS TO BE LIMITED BY
THE STRONG INVRN/MID LVL DRYNESS DEPICTED ON THE 00Z YPL RAOB. THE
AIRMASS IS TOO WARM/STABLE FOR LES.
&&
.SHORT TERM /TODAY THRU SUN NGT/... ISSUED AT 401 AM EST
IN THE NEAR TERM...
EXPECT LO CLDS OVER THE KEWEENAW/ERN CWA AS SHRTWV IN ONTARIO DIGS
SSEWD AND LO PRES TROF SHARPENS TOWARD THE ERN CWA. THE ARRIVAL OF
THIS CLD COVER WL PUT A CHECK ON THE DIURNAL TEMP DROP. WHERE SKIES
REMAIN MOCLR AND WINDS LGT TOWARD THE WI BORDER...EXPECT TEMPS TO
FALL NEAR OR BLO 10F.
TODAY...
GUIDANCE REMAINS FAIRLY CONSISTENT SHOWING SHRTWV NOW OVER FAR NW
ONTARIO DIGGING INTO ERN UPR MI BY 00Z. CLDS ASSOCIATED WITH THIS
FEATURE WL IMPACT MAINLY THE KEWEENAW AND ERN CWA. OPTED TO GO WITH
SCHC POPS OVER THE E NEAR OR JUST ON THE CYC SIDE OF THE SHRTWV
PASSAGE AND WHERE MODELS SHOW SHARPEST DPVA/DEEP LYR QVECTOR CNVGC.
WHILE THE CLDS OVER THE E WL LIMIT THE DIURNAL RECOVERY OF TEMP IN
THAT AREA...EXPECT THE MERCURY TO RECOVER TO WELL ABV NORMAL
READINGS OVER THE INTERIOR W AND SCNTRL TO ARND 40 PER MIXING TO H9
ON NAM FCST SDNGS.
TNGT...
SINCE THE AIRMASS TRAILING THE DEPARTING DISTURBANCE TO THE SE WL BE
TOO WARM FOR LES WITH H85 TEMPS FCST NO LOWER THAN ABOUT -5C...
EXPECT ANY LINGERING ISOLD -SHSN OVER THE E TO END EARLY ONCE THE
LARGER SCALE FORCING EXITS. WITH DNVA/DEEP LYR QVECTOR DVGC/UPR
CONFLUENCE DVLPG THRU THE NGT CONTRIBUTING TO A SHARPENING SFC RDG
AXIS/MORE ACYC FLOW/DRYING...EXPECT SKIES TO TURN MOCLR WITH
INSUFFICIENT INSTABILITY EVEN FOR LK CLDS EVEN UNDER THE MORE
PERSISTENT NNW FLOW FCST OVER THE E. THE LOWEST MIN TEMPS WL BE NEAR
THE WI BORDER AWAY FM LK MODERATION IN THE NW H925 FLOW AND WHERE
WINDS WL TURN NEAR CALM.
SUN/SUN NGT...
SFC RDG IS PROGGED TO SINK TO THE S...WITH STRONG 25-35KT H925 W
WIND DVLPG ON ITS NRN FLANK AND TO THE S OF SHRTWV/ATTENDANT COLD
FNT MOVING ESEWD THRU ONTARIO. THIS FLOW WL ADVECT UNSEASONABLY WARM
PACIFIC AIR INTO THE UPR LKS. WITH DRY AIRMASS/PLENTY OF SUNSHINE
AND H85 TEMPS PROGGED TO REACH ARND 3C ON SUN AFTN...EXPECT TEMPS TO
PEAK WELL INTO THE 40S...ESPECIALLY IN AREAS WHERE THE W WIND
DOWNSLOPES OVER THE CNTRL. PERSISTENT STEADY W WIND ON SUN NGT WL
LIMIT THE DIURNAL FALL OF TEMP DESPITE MOCLR SKIES.
.LONG TERM /MONDAY THROUGH NEXT FRIDAY/...
MAIN FEATURE INITIALLY IS TROUGH/COLD AIR DROPPING ACROSS EASTERN
CANADA AND GRAZING THE UPR LAKES INTO TUESDAY. HEIGHTS REBOUND SOME
INTO WEDNESDAY THEN APPEARS THAT AT LEAST PORTION OF POLAR VORTEX
OVR NORTHERN CANADA WILL TRY TO DROP ACROSS GREAT LAKES BY LATE WEEK.
DETAILS OF HOW THAT EXACTLY PLAYS OUT IS VERY MUCH IN DEBATE.
PRIMARY ISSUE TO START OFF IS ARRIVAL OF COLD FRONT/POP COVERAGE
LATER MONDAY INTO MONDAY EVENING. ECMWF PREFERRED BY HPC WITH COLD
AIR INTRUSION AND TIMING OF SFC COLD FRONT. 925-850MB TEMPS ONLY
BOTTOM OUT IN THE MID TEENS BLO ZERO BY TUESDAY AM...SO NOT TALKING
A REAL ARCTIC AIR MASS BUT WILL SURELY FEEL MUCH COLDER COMPARED TO
THE UNSEASONABLE WARMTH THAT WILL BE OVR THE AREA THROUGH MONDAY.
STEEPENING LOW-LEVEL LAPSE RATES /SFC-925MB LAPSE RATES OVR 8C/KM/
SHOULD RESULT IN ANY SNOW THAT DEVELOPS LATE MONDAY INTO MONDAY
EVENING ALONG AND AHEAD OF SFC COLD FRONT TO TAKE ON MUCH MORE OF A
CONVECTIVE NATURE. BOOSTED TEMPS AHEAD OF FRONT WITH MIXING TO 925MB
SUPPORTING HIGHS POSSIBLY NEAR 40 ONCE AGAIN...ESPECIALLY OVR SCNTRL
UPR MI WITH DOWNSLOPE WINDS EXPECTED THROUGH THE DAY AND GIVEN LATER
ARRIVAL OF THE COLD FRONT.
AFTER FROPA...THERE WILL BE A BRIEF PERIOD INTO MID MORNING TUESDAY
WHERE LOW-LEVEL WINDS AND SUFFICIENT MOISTURE BLO H7 COMBINES WITH
THE COLDER AIR TO LEAD TO SCT LK EFFECT SNOW SHOWERS. MAINLY NORTH
WINDS EXPECTED IN WAKE OF COLD FRONT...SO EXPECT BEST COVERAGE TO
SNOW SHOWERS OVR FAR WEST AND NORTH CENTRAL CWA. WOULD NOT BE
SURPRISED IS LINGERING SFC BASED INSTABILITY RESULTS IN LESS
ORGANIZED LK EFFECT /SCATTERED TRANSIENT POCKETS OF SNOW SHOWERS
VERSUS TYPICAL BANDED STRUCTURE/. SEEMS THAT WHATEVER LK EFFECT
IS AROUND TO BEGIN DAY TUESDAY SHOULD FADE QUICKLY WITH WARMING
925-850MB TEMPS AND SHARP DRYING IN THAT LAYER. ECMWF INDICATES
850MB RH FALLING TO LESS THAN 20 PCT BY 18Z TUESDAY AS HIGH
PRESSURE RAPIDLY SLIDES ACROSS. TRENDED POPS TO ACCOUNT FOR THE
DRYING BY HAVING HIGHEST POPS THROUGH 18Z THEN DROP TO SLIGHT CHANCE
IN THE AFTN. IF ECMWF IS CORRECT...MOST SNOW SHOWERS WOULD LIKELY BE
DONE BY MID MORNING ON TUESDAY.
WEST FLOW ALOFT WILL BRING RETURN TO WARMER THAN NORMAL TEMPS
WEDNESDAY AND MAYBE INTO THURSDAY. LATE WEEK RETURN OF COLDER AIR
STILL NOT SET JUST YET. LATEST ECMWF IS NOW QUITE DIFFERENT
COMPARED TO GFS BY DELAYING COLDER AIR RETURNING UNTIL LATER FRI.
GFS SHOWS COLD PUSHING BACK INTO UPR LAKES AS EARLY AS THURSDAY.
OTHER THAN TWEAKING TEMPS UPWARD SOME ON WEDNESDAY...GIVEN THE LACK
OF CONSISTENCY...HAVE KEPT WITH A CONSENSUS OF GUIDANCE FOR ALL FCST
ELEMENTS FOR THE REST OF THE EXTENDED.
&&
.AVIATION /FOR THE 18Z TAF ISSUANCE/...
WITH LINGERING UPSLOPE AIDED LOW CLOUDS CURRENTLY SCATTERING OUT AT
KCMX...VFR CONDITIONS SHOULD PREVAIL FOR THE REMAINDER OF THE AFTN.
VFR CONDITIONS WILL ALSO PREVAIL AT KIWD/KSAW THIS AFTN. LATER THIS
AFTN/EVENING...A LOW PRES TROF WILL PASS ACROSS UPPER MI. ALTHOUGH
LOW CLOUDS (IFR/LOW MVFR) ARE TENDING TO DISSIPATE NW AND N OF LAKE
SUPERIOR AND STATISTICAL GUIDANCE MAINTAINS VFR CLOUD BASES...OPTED
TO BRING A PERIOD OF LOW MVFR CIGS TO KCMX/KSAW AFTER TROF PASSAGE
THIS EVENING AS WINDS VEER MORE NORTHERLY AND DAYTIME MIXING ENDS.
NOT OUT OF THE QUESTION THAT IFR CIGS COULD DEVELOP. KIWD SHOULD BE
W OF THE BETTER PUSH OF LOW-LEVEL MOISTURE...SO KEPT CLOUDS SCT
THERE. VFR CONDITIONS WILL RETURN TO KCMX/KSAW LATE TONIGHT/SUN
MORNING AS WINDS BACK WESTERLY.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST/...
WEST WINDS UP TO 20 KT TODAY WILL DIMINISH TONIGHT INTO SUNDAY
MORNING AS HIGH PRESSURE BUILDS ACROSS THE REGION. WESTERLY WINDS
INCREASE TO 25 KT SUNDAY AFTN INTO SUN NIGHT AS THE RIDGE MOVES TO
THE SOUTH TOWARD THE LOWER LAKES AND OHIO VALLEY. A COLD FRONT WILL
PUSH ACROSS LAKE SUPERIOR LATE MONDAY AFTN. EXPECT WINDS UP TO 30
KT ALONG WITH SOME FREEZING SPRAY IN WAKE OF THE FRONT MONDAY NIGHT
INTO TUESDAY MORNING. LIGHER WINDS DEVELOP INTO WEDNESDAY AS ANOTHER
HIGH PRESSURE SLIDES INTO THE AREA. STRONGER WEST WINDS ARE EXPECTED
LATER WEDNESDAY INTO THURSDAY OUT AHEAD OF ANOTHER COLD FRONT
DROPPING INTO THE AREA FM CANADA. NW GALES ARE POSSIBLE BEGINNING
LATER THURSDAY BEHIND THE COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...NONE.
LAKE SUPERIOR...NONE.
LAKE MICHIGAN...NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...ROLFSON
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
632 AM EST SAT FEB 4 2012
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER WRN CAN AND TROF OVER QUEBEC. THIS
NW FLOW ALF IS KEEPING THE CLOSED LO RESPONSIBLE FOR HEAVY SN IN
COLORADO WELL TO THE SW OF THE UPR LKS...AND THIS WL REMAIN THE CASE
THRU THE WEEKEND. ALTHOUGH A NW FLOW ALF IS OFTEN ASSOCIATED WITH
VERY COLD AIR THIS TIME OF YEAR...THE AIRMASS OVER W AND CNTRL CAN
AS WELL AS THE NRN TIER OF THE CONUS IS PACIFIC IN ORIGIN. 00Z H85
TEMPS RANGE FM -4C AT APX/YPL TO -3C AT INL AND -2C AT GRB. AT THE
PAS NEAR LK WINNIPEG IN MANITOBA...THE 00Z H85 TEMP WAS 0C. COLDER
AIR IS PRESENT TO THE NE TOWARD THE VORTEX IN QUEBEC...BUT EVEN
THERE THE 00Z H85 TEMP WAS JUST -15C AT MOOSONEE AT THE S END OF
JAMES BAY. SINCE THE CWA IS NEAR THE CONFLUENCE ZN BTWN THE
PREVAILING NW FLOW ALF AND A SLY FLOW TO THE E OF THE CUTOFF LO IN
THE PLAINS...A SFC HI PRES RDG IS PRESENT FM MN ESEWD INTO LOWER MI.
LOCAL 00Z RAOBS SHOW A SHARP INVRN BTWN H85-95 ASSOCIATED WITH LARGE
SCALE SUBSIDENCE. TEMPS OVER THE CWA HAVE FALLEN SHARPLY EARLY THIS
MRNG TOWARD 10 ABOVE...ESPECIALLY OVER THE INTERIOR W UNDER THE
ACCOMPANYING MOCLR SKIES. BUT THERE IS QUITE A BIT OF LO CLD
STRETCHING FM ERN UPR MI N AND NWWD INTO ONTARIO WITH MSTR TRAPPED
BLO INVRN ALONG A SFC TROF ASSOCIATED WITH A SHRTWV DIGGING SEWD IN
THE NW FLOW ALF. ACCOMPANYING PCPN COVERAGE APPEARS TO BE LIMITED BY
THE STRONG INVRN/MID LVL DRYNESS DEPICTED ON THE 00Z YPL RAOB. THE
AIRMASS IS TOO WARM/STABLE FOR LES.
&&
.SHORT TERM /TODAY THRU SUN NGT/...
IN THE NEAR TERM...
EXPECT LO CLDS OVER THE KEWEENAW/ERN CWA AS SHRTWV IN ONTARIO DIGS
SSEWD AND LO PRES TROF SHARPENS TOWARD THE ERN CWA. THE ARRIVAL OF
THIS CLD COVER WL PUT A CHECK ON THE DIURNAL TEMP DROP. WHERE SKIES
REMAIN MOCLR AND WINDS LGT TOWARD THE WI BORDER...EXPECT TEMPS TO
FALL NEAR OR BLO 10F.
TODAY...
GUIDANCE REMAINS FAIRLY CONSISTENT SHOWING SHRTWV NOW OVER FAR NW
ONTARIO DIGGING INTO ERN UPR MI BY 00Z. CLDS ASSOCIATED WITH THIS
FEATURE WL IMPACT MAINLY THE KEWEENAW AND ERN CWA. OPTED TO GO WITH
SCHC POPS OVER THE E NEAR OR JUST ON THE CYC SIDE OF THE SHRTWV
PASSAGE AND WHERE MODELS SHOW SHARPEST DPVA/DEEP LYR QVECTOR CNVGC.
WHILE THE CLDS OVER THE E WL LIMIT THE DIURNAL RECOVERY OF TEMP IN
THAT AREA...EXPECT THE MERCURY TO RECOVER TO WELL ABV NORMAL
READINGS OVER THE INTERIOR W AND SCNTRL TO ARND 40 PER MIXING TO H9
ON NAM FCST SDNGS.
TNGT...
SINCE THE AIRMASS TRAILING THE DEPARTING DISTURBANCE TO THE SE WL BE
TOO WARM FOR LES WITH H85 TEMPS FCST NO LOWER THAN ABOUT -5C...
EXPECT ANY LINGERING ISOLD -SHSN OVER THE E TO END EARLY ONCE THE
LARGER SCALE FORCING EXITS. WITH DNVA/DEEP LYR QVECTOR DVGC/UPR
CONFLUENCE DVLPG THRU THE NGT CONTRIBUTING TO A SHARPENING SFC RDG
AXIS/MORE ACYC FLOW/DRYING...EXPECT SKIES TO TURN MOCLR WITH
INSUFFICIENT INSTABILITY EVEN FOR LK CLDS EVEN UNDER THE MORE
PERSISTENT NNW FLOW FCST OVER THE E. THE LOWEST MIN TEMPS WL BE NEAR
THE WI BORDER AWAY FM LK MODERATION IN THE NW H925 FLOW AND WHERE
WINDS WL TURN NEAR CALM.
SUN/SUN NGT...
SFC RDG IS PROGGED TO SINK TO THE S...WITH STRONG 25-35KT H925 W
WIND DVLPG ON ITS NRN FLANK AND TO THE S OF SHRTWV/ATTENDANT COLD
FNT MOVING ESEWD THRU ONTARIO. THIS FLOW WL ADVECT UNSEASONABLY WARM
PACIFIC AIR INTO THE UPR LKS. WITH DRY AIRMASS/PLENTY OF SUNSHINE
AND H85 TEMPS PROGGED TO REACH ARND 3C ON SUN AFTN...EXPECT TEMPS TO
PEAK WELL INTO THE 40S...ESPECIALLY IN AREAS WHERE THE W WIND
DOWNSLOPES OVER THE CNTRL. PERSISTENT STEADY W WIND ON SUN NGT WL
LIMIT THE DIURNAL FALL OF TEMP DESPITE MOCLR SKIES.
.LONG TERM /MONDAY THROUGH NEXT FRIDAY/...
MAIN FEATURE INITIALLY IS TROUGH/COLD AIR DROPPING ACROSS EASTERN
CANADA AND GRAZING THE UPR LAKES INTO TUESDAY. HEIGHTS REBOUND SOME
INTO WEDNESDAY THEN APPEARS THAT AT LEAST PORTION OF POLAR VORTEX
OVR NORTHERN CANADA WILL TRY TO DROP ACROSS GREAT LAKES BY LATE WEEK.
DETAILS OF HOW THAT EXACTLY PLAYS OUT IS VERY MUCH IN DEBATE.
PRIMARY ISSUE TO START OFF IS ARRIVAL OF COLD FRONT/POP COVERAGE
LATER MONDAY INTO MONDAY EVENING. ECMWF PREFERRED BY HPC WITH COLD
AIR INTRUSION AND TIMING OF SFC COLD FRONT. 925-850MB TEMPS ONLY
BOTTOM OUT IN THE MID TEENS BLO ZERO BY TUESDAY AM...SO NOT TALKING
A REAL ARCTIC AIR MASS BUT WILL SURELY FEEL MUCH COLDER COMPARED TO
THE UNSEASONABLE WARMTH THAT WILL BE OVR THE AREA THROUGH MONDAY.
STEEPENING LOW-LEVEL LAPSE RATES /SFC-925MB LAPSE RATES OVR 8C/KM/
SHOULD RESULT IN ANY SNOW THAT DEVELOPS LATE MONDAY INTO MONDAY
EVENING ALONG AND AHEAD OF SFC COLD FRONT TO TAKE ON MUCH MORE OF A
CONVECTIVE NATURE. BOOSTED TEMPS AHEAD OF FRONT WITH MIXING TO 925MB
SUPPORTING HIGHS POSSIBLY NEAR 40 ONCE AGAIN...ESPECIALLY OVR SCNTRL
UPR MI WITH DOWNSLOPE WINDS EXPECTED THROUGH THE DAY AND GIVEN LATER
ARRIVAL OF THE COLD FRONT.
AFTER FROPA...THERE WILL BE A BRIEF PERIOD INTO MID MORNING TUESDAY
WHERE LOW-LEVEL WINDS AND SUFFICIENT MOISTURE BLO H7 COMBINES WITH
THE COLDER AIR TO LEAD TO SCT LK EFFECT SNOW SHOWERS. MAINLY NORTH
WINDS EXPECTED IN WAKE OF COLD FRONT...SO EXPECT BEST COVERAGE TO
SNOW SHOWERS OVR FAR WEST AND NORTH CENTRAL CWA. WOULD NOT BE
SURPRISED IS LINGERING SFC BASED INSTABILITY RESULTS IN LESS
ORGANIZED LK EFFECT /SCATTERED TRANSIENT POCKETS OF SNOW SHOWERS
VERSUS TYPICAL BANDED STRUCTURE/. SEEMS THAT WHATEVER LK EFFECT
IS AROUND TO BEGIN DAY TUESDAY SHOULD FADE QUICKLY WITH WARMING
925-850MB TEMPS AND SHARP DRYING IN THAT LAYER. ECMWF INDICATES
850MB RH FALLING TO LESS THAN 20 PCT BY 18Z TUESDAY AS HIGH
PRESSURE RAPIDLY SLIDES ACROSS. TRENDED POPS TO ACCOUNT FOR THE
DRYING BY HAVING HIGHEST POPS THROUGH 18Z THEN DROP TO SLIGHT CHANCE
IN THE AFTN. IF ECMWF IS CORRECT...MOST SNOW SHOWERS WOULD LIKELY BE
DONE BY MID MORNING ON TUESDAY.
WEST FLOW ALOFT WILL BRING RETURN TO WARMER THAN NORMAL TEMPS
WEDNESDAY AND MAYBE INTO THURSDAY. LATE WEEK RETURN OF COLDER AIR
STILL NOT SET JUST YET. LATEST ECMWF IS NOW QUITE DIFFERENT
COMPARED TO GFS BY DELAYING COLDER AIR RETURNING UNTIL LATER FRI.
GFS SHOWS COLD PUSHING BACK INTO UPR LAKES AS EARLY AS THURSDAY.
OTHER THAN TWEAKING TEMPS UPWARD SOME ON WEDNESDAY...GIVEN THE LACK
OF CONSISTENCY...HAVE KEPT WITH A CONSENSUS OF GUIDANCE FOR ALL FCST
ELEMENTS FOR THE REST OF THE EXTENDED.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
THERE MAY BE SOME LO CLDS/IFR CIGS AT CMX EARLY THIS MORNING WITH
UPSLOPE WLY FLOW...BUT VFR CONDITIONS WL DOMINATE AT SAW/IWD THRU
THE DAY. AS THE FLOW VEERS TO THE NNW LATER TODAY INTO THIS EVNG
BEHIND A LO PRES TROF PASSAGE...THERE MAY BE A PERIOD OF LO CLDS/
MVFR CIGS AT CMX AND SAW CLOSER TO A DISTURBANCE TRACKING JUST TO
THE E OF UPR MI. HI PRES WL BUILD INTO THE AREA AGAIN LATER TNGT...
CAUSING VFR CONDITIONS TO DOMINATE.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST/...
WEST WINDS UP TO 20 KT TODAY WILL DIMINISH TONIGHT INTO SUNDAY
MORNING AS HIGH PRESSURE BUILDS ACROSS THE REGION. WESTERLY WINDS
INCREASE TO 25 KT SUNDAY AFTN INTO SUN NIGHT AS THE RIDGE MOVES TO
THE SOUTH TOWARD THE LOWER LAKES AND OHIO VALLEY. A COLD FRONT WILL
PUSH ACROSS LAKE SUPERIOR LATE MONDAY AFTN. EXPECT WINDS UP TO 30
KT ALONG WITH SOME FREEZING SPRAY IN WAKE OF THE FRONT MONDAY NIGHT
INTO TUESDAY MORNING. LIGHER WINDS DEVELOP INTO WEDNESDAY AS ANOTHER
HIGH PRESSURE SLIDES INTO THE AREA. STRONGER WEST WINDS ARE EXPECTED
LATER WEDNESDAY INTO THURSDAY OUT AHEAD OF ANOTHER COLD FRONT
DROPPING INTO THE AREA FM CANADA. NW GALES ARE POSSIBLE BEGINNING
LATER THURSDAY BEHIND THE COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...KC
MARINE...JLA
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
401 AM EST SAT FEB 4 2012
.SYNOPSIS...
00Z RAOBS/LATEST WV IMAGERY AND RUC ANALYSIS SHOW NW FLOW ALF OVER
THE UPR GRT LKS BTWN UPR RDG OVER WRN CAN AND TROF OVER QUEBEC. THIS
NW FLOW ALF IS KEEPING THE CLOSED LO RESPONSIBLE FOR HEAVY SN IN
COLORADO WELL TO THE SW OF THE UPR LKS...AND THIS WL REMAIN THE CASE
THRU THE WEEKEND. ALTHOUGH A NW FLOW ALF IS OFTEN ASSOCIATED WITH
VERY COLD AIR THIS TIME OF YEAR...THE AIRMASS OVER W AND CNTRL CAN
AS WELL AS THE NRN TIER OF THE CONUS IS PACIFIC IN ORIGIN. 00Z H85
TEMPS RANGE FM -4C AT APX/YPL TO -3C AT INL AND -2C AT GRB. AT THE
PAS NEAR LK WINNIPEG IN MANITOBA...THE 00Z H85 TEMP WAS 0C. COLDER
AIR IS PRESENT TO THE NE TOWARD THE VORTEX IN QUEBEC...BUT EVEN
THERE THE 00Z H85 TEMP WAS JUST -15C AT MOOSONEE AT THE S END OF
JAMES BAY. SINCE THE CWA IS NEAR THE CONFLUENCE ZN BTWN THE
PREVAILING NW FLOW ALF AND A SLY FLOW TO THE E OF THE CUTOFF LO IN
THE PLAINS...A SFC HI PRES RDG IS PRESENT FM MN ESEWD INTO LOWER MI.
LOCAL 00Z RAOBS SHOW A SHARP INVRN BTWN H85-95 ASSOCIATED WITH LARGE
SCALE SUBSIDENCE. TEMPS OVER THE CWA HAVE FALLEN SHARPLY EARLY THIS
MRNG TOWARD 10 ABOVE...ESPECIALLY OVER THE INTERIOR W UNDER THE
ACCOMPANYING MOCLR SKIES. BUT THERE IS QUITE A BIT OF LO CLD
STRETCHING FM ERN UPR MI N AND NWWD INTO ONTARIO WITH MSTR TRAPPED
BLO INVRN ALONG A SFC TROF ASSOCIATED WITH A SHRTWV DIGGING SEWD IN
THE NW FLOW ALF. ACCOMPANYING PCPN COVERAGE APPEARS TO BE LIMITED BY
THE STRONG INVRN/MID LVL DRYNESS DEPICTED ON THE 00Z YPL RAOB. THE
AIRMASS IS TOO WARM/STABLE FOR LES.
&&
.SHORT TERM /TODAY THRU SUN NGT/...
IN THE NEAR TERM...
EXPECT LO CLDS OVER THE KEWEENAW/ERN CWA AS SHRTWV IN ONTARIO DIGS
SSEWD AND LO PRES TROF SHARPENS TOWARD THE ERN CWA. THE ARRIVAL OF
THIS CLD COVER WL PUT A CHECK ON THE DIURNAL TEMP DROP. WHERE SKIES
REMAIN MOCLR AND WINDS LGT TOWARD THE WI BORDER...EXPECT TEMPS TO
FALL NEAR OR BLO 10F.
TODAY...
GUIDANCE REMAINS FAIRLY CONSISTENT SHOWING SHRTWV NOW OVER FAR NW
ONTARIO DIGGING INTO ERN UPR MI BY 00Z. CLDS ASSOCIATED WITH THIS
FEATURE WL IMPACT MAINLY THE KEWEENAW AND ERN CWA. OPTED TO GO WITH
SCHC POPS OVER THE E NEAR OR JUST ON THE CYC SIDE OF THE SHRTWV
PASSAGE AND WHERE MODELS SHOW SHARPEST DPVA/DEEP LYR QVECTOR CNVGC.
WHILE THE CLDS OVER THE E WL LIMIT THE DIURNAL RECOVERY OF TEMP IN
THAT AREA...EXPECT THE MERCURY TO RECOVER TO WELL ABV NORMAL
READINGS OVER THE INTERIOR W AND SCNTRL TO ARND 40 PER MIXING TO H9
ON NAM FCST SDNGS.
TNGT...
SINCE THE AIRMASS TRAILING THE DEPARTING DISTURBANCE TO THE SE WL BE
TOO WARM FOR LES WITH H85 TEMPS FCST NO LOWER THAN ABOUT -5C...
EXPECT ANY LINGERING ISOLD -SHSN OVER THE E TO END EARLY ONCE THE
LARGER SCALE FORCING EXITS. WITH DNVA/DEEP LYR QVECTOR DVGC/UPR
CONFLUENCE DVLPG THRU THE NGT CONTRIBUTING TO A SHARPENING SFC RDG
AXIS/MORE ACYC FLOW/DRYING...EXPECT SKIES TO TURN MOCLR WITH
INSUFFICIENT INSTABILITY EVEN FOR LK CLDS EVEN UNDER THE MORE
PERSISTENT NNW FLOW FCST OVER THE E. THE LOWEST MIN TEMPS WL BE NEAR
THE WI BORDER AWAY FM LK MODERATION IN THE NW H925 FLOW AND WHERE
WINDS WL TURN NEAR CALM.
SUN/SUN NGT...
SFC RDG IS PROGGED TO SINK TO THE S...WITH STRONG 25-35KT H925 W
WIND DVLPG ON ITS NRN FLANK AND TO THE S OF SHRTWV/ATTENDANT COLD
FNT MOVING ESEWD THRU ONTARIO. THIS FLOW WL ADVECT UNSEASONABLY WARM
PACIFIC AIR INTO THE UPR LKS. WITH DRY AIRMASS/PLENTY OF SUNSHINE
AND H85 TEMPS PROGGED TO REACH ARND 3C ON SUN AFTN...EXPECT TEMPS TO
PEAK WELL INTO THE 40S...ESPECIALLY IN AREAS WHERE THE W WIND
DOWNSLOPES OVER THE CNTRL. PERSISTENT STEADY W WIND ON SUN NGT WL
LIMIT THE DIURNAL FALL OF TEMP DESPITE MOCLR SKIES.
.LONG TERM /MONDAY THROUGH NEXT FRIDAY/...
MAIN FEATURE INITIALLY IS TROUGH/COLD AIR DROPPING ACROSS EASTERN
CANADA AND GRAZING THE UPR LAKES INTO TUESDAY. HEIGHTS REBOUND SOME
INTO WEDNESDAY THEN APPEARS THAT AT LEAST PORTION OF POLAR VORTEX
OVR NORTHERN CANADA WILL TRY TO DROP ACROSS GREAT LAKES BY LATE WEEK.
DETAILS OF HOW THAT EXACTLY PLAYS OUT IS VERY MUCH IN DEBATE.
PRIMARY ISSUE TO START OFF IS ARRIVAL OF COLD FRONT/POP COVERAGE
LATER MONDAY INTO MONDAY EVENING. ECMWF PREFERRED BY HPC WITH COLD
AIR INTRUSION AND TIMING OF SFC COLD FRONT. 925-850MB TEMPS ONLY
BOTTOM OUT IN THE MID TEENS BLO ZERO BY TUESDAY AM...SO NOT TALKING
A REAL ARCTIC AIR MASS BUT WILL SURELY FEEL MUCH COLDER COMPARED TO
THE UNSEASONABLE WARMTH THAT WILL BE OVR THE AREA THROUGH MONDAY.
STEEPENING LOW-LEVEL LAPSE RATES /SFC-925MB LAPSE RATES OVR 8C/KM/
SHOULD RESULT IN ANY SNOW THAT DEVELOPS LATE MONDAY INTO MONDAY
EVENING ALONG AND AHEAD OF SFC COLD FRONT TO TAKE ON MUCH MORE OF A
CONVECTIVE NATURE. BOOSTED TEMPS AHEAD OF FRONT WITH MIXING TO 925MB
SUPPORTING HIGHS POSSIBLY NEAR 40 ONCE AGAIN...ESPECIALLY OVR SCNTRL
UPR MI WITH DOWNSLOPE WINDS EXPECTED THROUGH THE DAY AND GIVEN LATER
ARRIVAL OF THE COLD FRONT.
AFTER FROPA...THERE WILL BE A BRIEF PERIOD INTO MID MORNING TUESDAY
WHERE LOW-LEVEL WINDS AND SUFFICIENT MOISTURE BLO H7 COMBINES WITH
THE COLDER AIR TO LEAD TO SCT LK EFFECT SNOW SHOWERS. MAINLY NORTH
WINDS EXPECTED IN WAKE OF COLD FRONT...SO EXPECT BEST COVERAGE TO
SNOW SHOWERS OVR FAR WEST AND NORTH CENTRAL CWA. WOULD NOT BE
SURPRISED IS LINGERING SFC BASED INSTABILITY RESULTS IN LESS
ORGANIZED LK EFFECT /SCATTERED TRANSIENT POCKETS OF SNOW SHOWERS
VERSUS TYPICAL BANDED STRUCTURE/. SEEMS THAT WHATEVER LK EFFECT
IS AROUND TO BEGIN DAY TUESDAY SHOULD FADE QUICKLY WITH WARMING
925-850MB TEMPS AND SHARP DRYING IN THAT LAYER. ECMWF INDICATES
850MB RH FALLING TO LESS THAN 20 PCT BY 18Z TUESDAY AS HIGH
PRESSURE RAPIDLY SLIDES ACROSS. TRENDED POPS TO ACCOUNT FOR THE
DRYING BY HAVING HIGHEST POPS THROUGH 18Z THEN DROP TO SLIGHT CHANCE
IN THE AFTN. IF ECMWF IS CORRECT...MOST SNOW SHOWERS WOULD LIKELY BE
DONE BY MID MORNING ON TUESDAY.
WEST FLOW ALOFT WILL BRING RETURN TO WARMER THAN NORMAL TEMPS
WEDNESDAY AND MAYBE INTO THURSDAY. LATE WEEK RETURN OF COLDER AIR
STILL NOT SET JUST YET. LATEST ECMWF IS NOW QUITE DIFFERENT
COMPARED TO GFS BY DELAYING COLDER AIR RETURNING UNTIL LATER FRI.
GFS SHOWS COLD PUSHING BACK INTO UPR LAKES AS EARLY AS THURSDAY.
OTHER THAN TWEAKING TEMPS UPWARD SOME ON WEDNESDAY...GIVEN THE LACK
OF CONSISTENCY...HAVE KEPT WITH A CONSENSUS OF GUIDANCE FOR ALL FCST
ELEMENTS FOR THE REST OF THE EXTENDED.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
PATCHY FOG OVERNIGHT COULD LEAD TO MVFR TO OCCASIONALLY VLIFR
CONDITIONS OVERNIGHT AT THE TAF SITES. LOOK FOR ANY LINGERING FOG TO
LIFT BY MID SAT MORNING AS VFR CONDITIONS SHOULD THEN PREVAIL.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST/...
WEST WINDS UP TO 20 KT TODAY WILL DIMINISH TONIGHT INTO SUNDAY
MORNING AS HIGH PRESSURE BUILDS ACROSS THE REGION. WESTERLY WINDS
INCREASE TO 25 KT SUNDAY AFTN INTO SUN NIGHT AS THE RIDGE MOVES TO
THE SOUTH TOWARD THE LOWER LAKES AND OHIO VALLEY. A COLD FRONT WILL
PUSH ACROSS LAKE SUPERIOR LATE MONDAY AFTN. EXPECT WINDS UP TO 30
KT ALONG WITH SOME FREEZING SPRAY IN WAKE OF THE FRONT MONDAY NIGHT
INTO TUESDAY MORNING. LIGHER WINDS DEVELOP INTO WEDNESDAY AS ANOTHER
HIGH PRESSURE SLIDES INTO THE AREA. STRONGER WEST WINDS ARE EXPECTED
LATER WEDNESDAY INTO THURSDAY OUT AHEAD OF ANOTHER COLD FRONT
DROPPING INTO THE AREA FM CANADA. NW GALES ARE POSSIBLE BEGINNING
LATER THURSDAY BEHIND THE COLD FRONT.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
NONE.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...KC
SHORT TERM...KC
LONG TERM...JLA
AVIATION...VOSS
MARINE...JLA
AREA FORECAST DISCUSSION
NWS DULUTH MN
1123 PM CST FRI FEB 3 2012
.AVIATION...06Z TAFS.
LIFR VSBYS/CIGS IN FZFG HAS FORMED OVER KINL/KHIB/KBRD. THIS WILL
CONTINUE UNTIL 16Z WHEN THE LOW CLOUDS AND FZFG ERODE TO VFR.
EXPECT VFR AT KDLH/KHYR. LOW CLOUDS/FZFG WILL HAVE TO BE CLOSELY
MONITORED FOR ITS IMPACT AT KDLH AS THEY TRY TO MOVE E.
&&
.PREV DISCUSSION... /ISSUED 909 PM CST FRI FEB 3 2012/
UPDATE...SOME DENSE FOG HAS FORMED IN THE SAME LOCATIONS AS LAST
NIGHT. HAVE ISSUED A DENSE FOG ADVISORY AS MORE LOCATIONS DEVELOP
DENSE FOG. HRRR AND LOCAL WRF CONFIRM THE DENSE FOG POSSIBILITY.
MADE A MINOR TWEAK TO MIN TEMPS. REST OF THE FORECAST UNCHANGED.
PREV DISCUSSION... /ISSUED 533 PM CST FRI FEB 3 2012/
AVIATION...00Z TAFS.
VFR AT THE OUTSET OF THIS FORECAST CYCLE. THE EXCEPTION BEING AT
KBRD WHERE IFR CIGS PREVAIL. SOME AREAS OF BR WITH MVFR OR IFR
VSBYS ARE POSSIBLE AT ALL LOCATIONS...EXCEPT KHYR...AS THE
ATMOSPHERE REMAINS THE SAME AS 24 HOURS AGO. KBRD MAY SEE VSBYS
DROP INTO THE LIFR RANGE IN BR. EXPECT KBRD TO IMPROVE TO VFR
AROUND 15Z WHEN LOW CLOUDS AND BR ERODE AND A NW WIND DEVELOPS.
PREV DISCUSSION... /ISSUED 312 PM CST FRI FEB 3 2012/
SHORT TERM...
FOCUS ON CLOUD COVER AND EXPANSION OF FOG OVERNIGHT. ALTHOUGH HAD
A SLOW START...SKIES ENDED UP QUICKLY CLEARING THIS AFTERNOON
FROM THE EAST ALLOWING TEMPS TO REACH THE UPPER 30S AND A FEW 40S.
THE EXCEPTION WAS IN THE BRAINERD AREA WHERE LOW CLOUDS HELD ON
AND TEMPS WERE ONLY ABLE TO BREAK 30 F. ALTHOUGH THE LOW LEVEL
MOISTURE IS QUITE SHALLOW...BASED ON CONDITIONS THE PAST FEW
NIGHTS...EXPECT THE LOW CLOUDS AND FOG TO RETURN TONIGHT. LATEST
NAM BUFR SOUNDINGS ARE SHOWING LOW LEVELS SATURATE THIS
EVENING...WITH INCREASING MIXING RATIOS WITH HT. THE LOWEST
VSBY/POSSIBLE DENSE FOG WILL BE IN THE WESTERN ZONES INCLUDING THE
KBRD AREA. CONFIDENCE NOT HIGH ENOUGH TO ISSUE A DENSE FOG
ADVISORY ATTM. HOWEVER...WILL HIGHLIGHT FOG IN THE HWO AND
AFTERNOON WX STORY GRAPHIC. KEPT TEMPS A FEW DEGREES ABV GUIDANCE
TONIGHT DUE TO CURRENT DWPNTS IN THE UPPER 20S AND ANTICIPATED
CLOUD COVER. LOW CLOUDS AND ANY FOG WILL DISSIPATE THROUGH
SATURDAY MORNING...REVEALING A MOSTLY SUNNY DAY WITH TEMPS WELL
ABOVE NORMAL IN THE 30S TO LOW 40S.
LONG TERM...[SUNDAY - THURSDAY]...
THE PERIOD SHOULD BEGIN WARMER THAN NORMAL AND MOSTLY DRY...WITH
MORE SEASONAL TEMPERATURES RETURNING FOR THE MIDDLE OF THE WEEK.
SUNDAY...THE NORTHLAND WILL BE IN AN UNUSUAL SITUATION OF WARM AIR
ADVECTION FROM THE NORTHWEST. THE SUNNY SKIES...LACK OF SNOW
COVER...AND WARM 850 HPA TEMPERATURES OF POSITIVE 2 TO 4
DEGREES...SHOULD GUARANTEE SOME HIGH TEMPERATURES IN THE 40S.
SUNDAY NIGHT INTO TUESDAY...A COLD FRONT WILL DROP SOUTH OUT OF
CANADA AND MOVE THROUGH THE NORTHLAND. THE FRONT LOOKS FAIRLY
DRY...EXCEPT THERE MAY BE SOME LAKE EFFECT SNOW SHOWERS ALONG THE
SOUTH SHORE MONDAY NIGHT AND TUESDAY WHEN THE COLDER AIR MOVES OVER
THE LAKE.
WEDNESDAY AND THURSDAY...ANOTHER COLD FRONT SHOULD PASS THROUGH THE
REGION. THE FRONT LOOKS DRY EXCEPT FOR THE CHANCE OF LAKE EFFECT
SHOWERS. THE TEMPERATURE FORECAST MAY NEED TO BE SIGNIFICANTLY
LOWERED OVER THE COMING DAYS WHEN THE MODELS COME INTO BETTER
AGREEMENT WITH THE DEGREE OF COLD AIR ADVECTION.
&&
.POINT TEMPS/POPS...
DLH 22 40 17 41 / 0 0 0 0
INL 21 37 14 38 / 0 0 0 0
BRD 22 38 19 39 / 0 0 0 0
HYR 20 41 17 40 / 0 0 0 0
ASX 23 41 19 41 / 0 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
MN...DENSE FOG ADVISORY UNTIL 10 AM CST SATURDAY FOR MNZ010-018-025-
026-033>036.
WI...NONE.
&&
$$
AVIATION...GSF
AREA FORECAST DISCUSSION
NWS KANSAS CITY/PLEASANT HILL MO
1140 PM CST Fri Feb 3 2012
...UPDATED AVIATION DISCUSSION...
.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 today`s 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 06z TAFs: An inverted surface trough stretching northwest
across central Kansas will slowly move eastward through the night as
accompanying surface low tracks through central Missouri. Persistent
low level warm advection and moisture convergence will allow
widespread light rain and drizzle to develop through the overnight
hours. IFR CIGS are already common across the terminals ATTM, and
should continue to fall into LIFR later this morning as the surface
trough approaches. Visibility is expected to vary from 2SM to 4SM
through the night. Highest probability of consistently falling less
than 2SM will be after 09Z and continue to 15Z as surface trough
remains overhead.
Models suggest some minor improvement in CIGS and VIS towards mid-day
as winds turn back to the north northwest. Northwest winds and
isentropic downglide would also bring an end to drizzle. Models
remain consistent in bringing decaying snow band across the terminals
during the late aftn and evening hours. Light snow accumulations less
than an inch may be possible especially at KSTJ and KMCI. Will only
include RASN mix at KC terminals, but this may be changed completely
to snow during later TAFs.
Dux
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
MO...WINTER WEATHER ADVISORY FROM 6 AM SATURDAY TO MIDNIGHT CST
SATURDAY NIGHT FOR MOZ001-002-011.
KS...NONE.
&&
$$
WFO EAX
AREA FORECAST DISCUSSION
NWS BILLINGS MT
332 AM MST SAT FEB 4 2012
.SHORT TERM...VALID FOR TDY AND SUN...
THE 00 UTC GUIDANCE CONTINUES ADVERTISING A REX BLOCK FOR THE NEXT
TWO DAYS AS A MID-LEVEL LOW GETS LEFT BEHIND OVER THE CENTRAL PART
OF THE ROCKIES WHILE A STRONG RIDGE SETTLES IN TO ITS NORTH. THERE
ARE +2 TO +3 STANDARD DEVIATION 700- TO 500-HPA HEIGHTS ASSOCIATED
WITH THE RIDGE THAT WILL INFLUENCE MT. THIS ESSENTIALLY ALLOWS FOR
A WARM PERIOD WITH RELATIVELY LIGHT WINDS...BUT THE WEAK FLOW WITH
THIS PATTERN HAS ALSO BEEN ENABLING FOG AND STRATUS ALONG AND EAST
OF A SURFACE RIDGE AXIS FROM EASTERN MT INTO THE DAKOTAS SINCE FRI
MORNING.
THE 00 UTC GLASGOW SOUNDING SUGGESTED THE INVERSION AND ASSOCIATED
SATURATED LAYER RESPONSIBLE FOR THE FOG IS BASED NEAR 900 HPA. THE
SHALLOW NATURE OF THE SATURATED LAYER IS CONFIRMED BY THE RELATIVE
LACK OF FOG AT EKALAKA SINCE LAST EVENING...WHICH IS ABOUT 1000 FT
HIGHER IN ELEVATION THAN MILES CITY AND 500 FT HIGHER THAN BAKER.
THE RUC AND HRRR RUNS FROM TONIGHT ARE THE ONLY MODELS THAT REALLY
CAPTURE THE CURRENT FOG SITUATION...AND BOTH SUGGEST THAT IT COULD
LINGER UNTIL AT LEAST 15 UTC. FORECAST SOUNDINGS FROM THE RUC PICK
UP ON THE SATURATED SURFACE TO 900-HPA LAYER IN THE MILES CITY AND
BAKER AREAS...AND DO NOT SHOW ENOUGH TURBULENT LOW-LEVEL MIXING TO
ERODE THE MOIST LAYER UNTIL BETWEEN 15 AND 20 UTC. WE WILL REQUIRE
THE 10-15 F DEWPOINT AIR FROM SHERIDAN TO GILLETTE TO ADVECT RIGHT
INTO THE MILES CITY AND BAKER AREAS TO HELP THIS ALONG. THAT COULD
GET A BIT OF A START BEFORE 15 UTC IF THE SURFACE RIDGE AXIS SLIPS
EAST AND LIGHT RETURN FLOW GETS GOING...BUT IN GENERAL PERSISTENCE
IS USUALLY A GOOD FORECAST WITH FOG AND STRATUS...SO WE WILL CARRY
THE DENSE FOG ADVISORY THROUGH 18 UTC FOR NOW...EVEN THOUGH WE MAY
HAVE SOME FLUCTUATION IN VISIBILITY THE NEXT FEW HOURS. THE FOG IS
STILL NOT AFFECTING ENOUGH OF CARTER COUNTY TO INCLUDE THEM IN THE
ADVISORY...SO WE WILL HOLD OFF ON ADDING THAT AREA AT THIS POINT.
TEMPERATURE-WISE...850-HPA TEMPERATURES WILL RISE SOME INTO THE +1
TO +3 C RANGE TODAY. WE USED THE HIGHS ON FRI AS A STARTING POINT
FOR TODAY/S FORECAST...AND THEN ADDED 5-8 F IN MOST AREAS BASED ON
THE WARMING ALOFT. OUTSIDE OF THE STRATUS-PLAGUED AREAS...THIS WAS
DONE IN ORDER TO CAPTURE THE FACT THAT BARE GROUND AND SUBSTANTIAL
INSOLATION DID GIVE AN EXTRA BOOST TO TEMPERATURES ABOVE WHAT PURE
MIXING WOULD HAVE IMPLIED ON FRI. FORECAST SOUNDINGS MIX CLOSE TO
850 HPA AGAIN TODAY OVER SOUTH CENTRAL MT AND UP TO 900 HPA ACROSS
SOUTHEASTERN MT...AND MANUAL MIX-DOWN FROM THOSE LEVELS DOES YIELD
HIGHS JUST SHORT OF WHAT WE ARE FORECASTING IN MOST CASES. PERHAPS
THE GREATEST UNCERTAINTY IN TODAY/S TEMPERATURE FORECAST IS ACROSS
THE BAKER AREA...AS HIGHS WOULD LIKELY BE HELD AT 32 F OR POSSIBLY
EVEN A BIT BELOW THAT IF STRATUS PREVAILS ALL DAY. WE BELIEVE THAT
THE STRATUS WILL DISSIPATE DURING THE AFTERNOON LIKE BOTH THE HRRR
AND RUC SHOW...AND AS SUCH ARE CALLING FOR HIGHS AROUND 35 F TO GO
WITH THE ASSUMPTION THAT LATE-DAY HEATING WILL OCCUR. OF COURSE...
WE HAVE ONLY MODERATE CONFIDENCE IN THIS OUTCOME.
ON SUN...THE MODELS AGREE THAT 850-HPA TEMPERATURES RISE TO THE +4
TO +6 RANGE...SO MANY AREAS WILL LIKELY MEET OR EXCEED 50 F. WHILE
WE DID INCREASE FORECAST HIGHS A FEW DEGREES F...IT IS POSSIBLE WE
ARE NOT WARM ENOUGH IN SOME AREAS ON SUN. SCHULTZ
.LONG TERM...VALID FOR MON...TUE...WED...THU...FRI...
SEASONAL TEMPERATURES AND A BETTER CHANCE OF SNOW FOR THE EXTENDED
FORECAST. HIGH OVER LOW BLOCKING PATTERN BREAKS DOWN ON MONDAY
WITH UPPER LOW TO THE SOUTH AND APPROACHING LOBE OFF THE HUDSON
BAY LOW TO THE NORTHEAST BEGIN TO INFLUENCE WEATHER OVER THE
REGION. LOW LEVEL COLD AIR WILL DROP INTO THE AREA FROM THE NORTH
MONDAY AS SURFACE PRESSURES LOWER OVER THE WESTERN
DAKOTAS...PUSHING TEMPERATURES JUST BELOW SEASONAL LEVELS MONDAY
AFTERNOON AND TUESDAY. MARGINAL MOISTURE SHOULD BE ENOUGH TO
PRODUCE ISOLATED TO SCATTERED SNOW SHOWERS BEHIND THE
FRONT...CONTINUING INTO TUESDAY AS WARM ADVECTION OVER RUNS THE
SHALLOW COLD AIRMASS. NORTHWEST FLOW ALOFT WILL HELP TO SCOUR OUT
CANADIAN AIR FROM WESTERN AREAS WEDNESDAY...WARMING TEMPERATURES
INTO THE LOWER 40S. DOWNSLOPE SHOULD KEEP ANY SNOW SHOWERS
CONFINED TO THE MOUNTAINS. AS DISCUSSED YESTERDAY UPPER RIDGE
DEVELOPS OVER THE WEST COAST WITH THE HUDSON BAY LOW SPINNING
CHUNKS OF ARCTIC AIR SOUTHWARD INTO THE MIDDLE OF THE COUNTRY.
LAST FEW MODEL RUNS HAVE TRENDED THIS RIDGING WESTWARD OPENING THE
DOOR AT LEAST A LITTLE BIT FOR COLDER ARCTIC AIR TO BUILD IN FROM
THE NORTHEAST. STILL TOO MUCH UNCERTAINTY TO MAKE ANY BIG CHANGES
TO THE EXTENDED...HOWEVER DID BEGIN TRENDING TEMPERATURES
COOLER...REMOVING THE WELL ABOVE AVERAGE TEMPERATURES THAT WERE IN
THE FORECAST. ALSO ADDED MENTION OF LOW POPS AS ANY COLD FRONT
SHOULD BE ABLE TO SQUEEZE OUT A FEW SNOW SHOWERS. OVERALL NOT TOO
CONCERNED ABOUT SNOWFALL AS THE ATMOSPHERE OVER THE AREA IS
BASICALLY CUT OFF FROM PACIFIC MOISTURE THROUGH THE EXTENDED. WILL
NEED TO KEEP A CLOSE EYE ON THE WEDNESDAY THROUGH SATURDAY PERIOD
FOR A MORE PRONOUNCED COLD AIR PLUNGE. CHAMBERS
&&
.AVIATION...
LIFR OR LOWER CONDITIONS WILL CONTINUE EAST OF A MILES CITY TO
ALZADA LINE THROUGH LATE THIS MORNING. CONDITIONS BELOW AIRPORT
MINIMUMS CAN BE EXPECTED AT KMLS AND KBHK THROUGH AT LEAST 16Z.
EXPECT FOG AND STRATUS TO DISSIPATE MID DAY. OTHERWISE VFR
CONDITIONS CAN BE EXPECTED TODAY. CHAMBERS
&&
.PRELIMINARY POINT TEMP/POPS...
TDY SUN MON TUE WED THU FRI
-------------------------------------------------------
BIL 046 025/052 022/032 015/031 019/039 021/040 025/042
0/U 00/U 02/J 32/J 11/B 12/J 11/B
LVM 046 018/051 019/039 020/036 021/044 023/045 025/047
0/U 00/U 01/B 31/B 11/U 22/W 11/B
HDN 047 018/053 021/032 015/033 014/039 016/038 019/040
0/U 00/U 02/J 32/J 11/B 12/J 11/B
MLS 044 022/051 022/032 015/031 015/038 016/034 017/036
0/F 00/U 02/J 31/B 11/B 12/J 11/B
4BQ 044 020/049 022/034 015/031 016/038 017/035 018/037
0/B 00/U 02/J 32/J 11/U 12/J 11/B
BHK 035 022/049 020/033 010/027 010/036 012/033 012/035
0/F 00/U 01/B 21/B 11/U 12/J 11/B
SHR 046 015/048 018/036 016/034 016/041 017/040 021/042
0/U 00/U 02/J 42/J 11/U 12/J 11/B
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...DENSE FOG ADVISORY IN EFFECT UNTIL 11 AM MST THIS MORNING FOR
ZONES 32-33.
WY...NONE.
&&
$$
WEATHER.GOV/BILLINGS
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
949 PM CST SUN FEB 5 2012
.UPDATE...
UPDATED TO ADD DENSE FOG ADVISORY.
&&
.DISCUSSION...
THE STRATUS DECK IS SLOWLY MAKING WWD PROGRESS ACROSS THE CTNRL
PART OF THE CWA. THE OPERATIONAL MODELS CONT TO STRUGGLE WITH THIS
NEAR GROUND LAYER DECK. ON THE WESTERN EDGE OF THIS DECK THE
TEMPERATURES FELL RAPIDLY THIS EVENING AND ALLOW FOR DENSE FOG TO
DVLP WITH ALL THE LOW LEVEL MOISTURE AROUND AND LIGHT WINDS. WOULD
EXPECT THE DECK TO CONT TO MAKE VERY SLOW PROGRESS TO THE WEST
OVERNIGHT...ESPECIALLY IN SE NEB WHERE THE WINDS JUST OFF THE SFC
ARE WEAKER THAN IN NE NEB. OTHERWISE THE DENSE FOG SHOULD BE
FAIRLY WIDESPREAD OVERNIGHT. LATE TONIGHT THE LOW LEVEL GRADIENT
STARTS TO INCREASE A LITTLE AND BY MON MRNG THIS SHOULD START TO
MOV THE STRATUS BACK EWD.
BOUSTEAD
&&
.PREV DISCUSSION... /ISSUED 547 PM CST SUN FEB 5 2012/
AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK.
MAY CONCERN IS FOG AND THE STRATUS DECK. NEARLY ALL OPERATIONAL
GUIDANCE HAS LITTLE HANDLE ON THE CURRENT SITUATION AND THUS
FORECAST CONFIDENCE IS PRETTY LOW ATTM. THE HRRR AT LEAST KNOWS THE
LOW CLOUDS ARE THERE AND WILL LEAD ON THIS MODEL FOR THE VERY SHORT
TERM. THE EWD PROGRESS OF THE LOW CLOUDS SHOULD STALL THIS EVNG AND
WILL KEEP OMA IN LIFR CONDS THRU THE NIGHT. WITH THE SURFACE RIDGE
IN SE NEB THE STRATUS MAY TRY BUILD BACK TOWARD LNK...BUT SHOULD
STAY E OF OFK THRU THE NIGHT. ALSO IF AND WHERE FOG WILL DVLP
TONIGHT. WITH A GENERAL WEAK SURFACE GRADIENT AND PLENTY OF LOW
LEVEL MOISTURE WE FEEL FOG IS A PRETTY GOOD BET DESPITE THE GUIDANCE
AND WILL HAVE FZFG IN ALL TAF SITES OVERNIGHT. GRADIENT DOES
INCREASE ON MON AHEAD OF THE COLD FRONT FOR TUE AND THUS WILL TRY
AND MOVE THE CLOUDS OUT BY MID TO LATE MORNING.
BOUSTEAD
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
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CST MONDAY FOR NEZ015-017-018-
030>034-042>045-050>053-065>068-078-088>093.
IA...DENSE FOG ADVISORY UNTIL 9 AM CST MONDAY FOR IAZ043-055-056-069-
079-080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
547 PM CST SUN FEB 5 2012
.AVIATION...
00Z TAFS FOR KOFK...KOMA AND KLNK.
MAY CONCERN IS FOG AND THE STRATUS DECK. NEARLY ALL OPERATIONAL
GUIDANCE HAS LITTLE HANDLE ON THE CURRENT SITUATION AND THUS
FORECAST CONFIDENCE IS PRETTY LOW ATTM. THE HRRR AT LEAST KNOWS THE
LOW CLOUDS ARE THERE AND WILL LEAD ON THIS MODEL FOR THE VERY SHORT
TERM. THE EWD PROGRESS OF THE LOW CLOUDS SHOULD STALL THIS EVNG AND
WILL KEEP OMA IN LIFR CONDS THRU THE NIGHT. WITH THE SURFACE RIDGE
IN SE NEB THE STRATUS MAY TRY BUILD BACK TOWARD LNK...BUT SHOULD
STAY E OF OFK THRU THE NIGHT. ALSO IF AND WHERE FOG WILL DVLP
TONIGHT. WITH A GENERAL WEAK SURFACE GRADIENT AND PLENTY OF LOW
LEVEL MOISTURE WE FEEL FOG IS A PRETTY GOOD BET DESPITE THE GUIDANCE
AND WILL HAVE FZFG IN ALL TAF SITES OVERNIGHT. GRADIENT DOES
INCREASE ON MON AHEAD OF THE COLD FRONT FOR TUE AND THUS WILL TRY
AND MOVE THE CLOUDS OUT BY MID TO LATE MORNING.
BOUSTEAD
&&
.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
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...NONE.
&&
$$
AREA FORECAST DISCUSSION...UPDATED
NWS NORTH PLATTE NE
1128 PM CST FRI FEB 3 2012
.UPDATE...
.AVIATION...
WIDESPREAD IFR/LIFR CONTINUE OVERNIGHT AS A WINTER STORM RAGES
THROUGH THE CENTRAL PLAINS. FLIGHT CONDITIONS IMPROVE TO VFR/MVFR
FROM WEST TO EAST OVERNIGHT AND DURING THE DAY SATURDAY AS THE
SFC LOW TRACKS THROUGH OKLAHOMA AND INTO MISSOURI.
&&
.PREV DISCUSSION... /ISSUED 828 PM CST FRI FEB 3 2012/
UPDATE...
DISCUSSION...
RAISED THE STORM TOTAL SNOWFALL UP AROUND TRYON TO 22 INCHES BASED
ON A REPORT OF 17 INCHES AT RINGOLD...RADAR TRENDS AND THE LATEST
HRRR/RUC SOLNS THROUGH THE NEXT 12 HRS.
BOTH THE HRRR AND RUC ARE BRINGING SECOND BAND OF SNOW NORTHWEST.
THE RUC PUSHES HEAVY SNOW TO HIGHWAY 83 AND THE HRRR TO HIGHWAY 61
BRIEFLY. THUS WE EXPECT THE SNOW TO PICK UP AND BECOME HEAVY AT TIMES OR
AT LEAST CONTINUE LIGHT TO MODERATE.
A NEW WIND FORECAST WAS DERIVED FROM THE RUC AND NAM WHICH PUSHES
WINDS OF TO 20 TO 30 MPH SUSTAINED WITH GUSTS TO 35 MPH. THIS MORE
CLOSELY REFLECTS CURRENT SFC OBS. THIS SHOULD CAUSE VISIBILITY TO
FALL BELOW 1/4 MILE DURING PERIODS OF MODERATE TO HEAVY
SNOW...MAINLY ALONG AND EAST OF HIGHWAY 83 WHERE WINDS WILL BE
STRONGEST AS THE SFC LOW TRACKS FROM SRN OK INTO WRN MO BY 12Z
SATURDAY. THUS IF THE RUC AND HRRR ARE RIGHT...BLIZZARD CONDITIONS
COULD DEVELOP OVERNIGHT IN SOME AREAS.
PREV DISCUSSION... /ISSUED 538 PM CST FRI FEB 3 2012/
UPDATE...
AVIATION...
WIDESPREAD IFR/LIFR CONTINUES OVERNIGHT AS A WINTER STORM RAGES
THROUGH THE CENTRAL PLAINS. FLIGHT CONDITIONS IMPROVE TO VFR/MVFR FROM
WEST TO EAST SATURDAY AS THE SFC LOW TRACKS THROUGH KANSAS AND
INTO IOWA.
PREV DISCUSSION... /ISSUED 305 PM CST FRI FEB 3 2012/
SYNOPSIS...PIECE ONE OF OUR WINTER STORM IS WELL UNDERWAY WITH SNOW
BEING REPORTED ACROSS MOST OF THE CWA THIS AFTERNOON. ACCUMULATIONS
OF 6 TO 12 INCHES WERE REPORTED ALONG A BAND FROM PERKINS
COUNTY...INTO THOMAS COUNTY. OVER THE PAST COUPLE OF HRS...12+
INCHES WAS REPORTED IN THE STAPLETON AND RINGGOLD AREAS. AT NORTH
PLATTE...WE HAVE AROUND AN INCH ON THE GROUND IN THE VALLEY...WHILE
NORTH AND SOUTH OF TOWN...6+ INCHES HAS BEEN REPORTED.
WV IMAGERY THIS AFTERNOON IS INDICATING LOW PRESSURE OVER SWRN KS
WITH A BROAD AREA OF THUNDERSTORMS EXTENDING FROM CENTRAL MO...INTO
CENTRAL TX. A MID LEVEL DRY PUSH WAST NOTED FROM SERN NM INTO THE TX
PANHANDLE. AT THE SURFACE...LOW PRESSURE WAS LOCATED OVER NRN
TEXAS...WITH A INVERTED TROUGH EXTENDING NWD INTO CENTRAL KS AND
CENTRAL NEBRASKA. STRONG HIGH PRESSURE WAS NOTED OVER NWRN MT.
DISCUSSION...
NEAR TERM...TONIGHT THROUGH SUNDAY...SNOW ACCUMULATIONS WILL BE THE
MAIN FORECASTING CHALLENGE OVER THE NEXT 24 HOURS AS THIS WINTER
SYSTEM CONTINUES TO EVOLVE. INTENSITY OF MID LEVEL FRONTOGENESIS AND
ASSOCIATED LIFT IS EXPECTED TO DECREASE LATER THIS AFTERNOON...AS
THE MAIN UPPER LEVEL LOW BEGINS TO EMERGE AND TRACK ACROSS CENTRAL
KANSAS. PRECIPITATION INTENSITY SHOULD BEGIN TO DECREASE AS WELL
LATER THIS AFTERNOON ACROSS THE AREA AS FORCING TEMPORALLY WEAKENS
AND TRANSITIONS SOUTH.
THE MAIN UPPER LEVEL LOW WILL TRACK FROM SWRN KS INTO CENTRAL KS
THIS EVENING. MID LEVEL FRONTOGENESIS AND LIFT WILL INCREASE ACROSS
CENTRAL AND SERN NEBRASKA THIS EVENING SPREADING SNOW TO THE
SOUTHEASTERN AND EASTERN CWA. INTENSE SNOWFALL RATES OF 1 TO 2
INCHES PER HOUR WILL BE POSSIBLE WITH THIS AREA OF STRONG
LIFT...WHICH IS FOCUSED JUST OFF TO THE SOUTHEAST OF THE FORECAST
AREA. NONE THE LESS...SNOWFALL RATES IN THE EASTERN AND SERN CWA OF
AROUND AN INCH AN HOUR THIS EVENING AND TONIGHT LOOK LIKE A DECENT SHOT.
FORECAST TRENDS ALONG WITH THE LATEST MODEL GUIDANCE FOCUS THE
HEAVIEST SNOW EAST OF A LINE FROM HAYES CENTER...TO NORTH
PLATTE...TO BROKEN BOW...AND BARTLETT...WITH A GOOD POTENTIAL FOR
8...UP TO 12 INCHES IN THESE AREAS. SURFACE LOW PRESSURE WILL
INTENSIFY IN RESPONSE TO CONVECTION OVER ERN KS TONIGHT. AT THE SAME
TIME...HIGH PRESSURE BUILDING INTO THE DAKOTAS...WILL TIGHTEN THE
PRESSURE GRADIENT LEADING TO WINDY CONDITIONS ACROSS THE FORECAST
AREA OVERNIGHT. THE WINDIEST CONDITIONS ARE EXPECTED OVER THE
CENTRAL AND SERN ZONES...WHICH UNFORTUNATELY IS CO LOCATED WITH THE
HEAVIEST SNOW. ATTM...WE ARE EXPECTING SOME NASTY CONDITIONS FROM
LATE EVENING INTO THE OVERNIGHT HOURS IN THE SERN ZONES...AND
WOULDN`T BE SURPRISED IF SOME NEAR BLIZZARD CONDS DEVELOP.
WILL PLAN ON LEAVING HEADLINES AS IS FOR NOW...AND BASED ON ONGOING
RPTS FROM THE CENTRAL SANDHILLS...MAY NEED TO EXPAND THE WINTER
WEATHER ADVISORY INTO WESTERN CHERRY COUNTY.
LONG TERM...SUNDAY NIGHT THROUGH FRIDAY...MAIN FOCUS WILL BE
TEMPS...AS THE HEAVY SNOW FROM CURRENT THE WINTER STORM WILL HAVE A
COOLING EFFECT. MONDAY SURFACE HIGH PRESSURE WILL DOMINATE THE
PLAINS WITH DRY AND SEASONAL TEMPERATURES. HIGHS HOLD IN THE MID AND
UPPER 30S...WHERE SNOW LINGERS...WITH LOWER 40S ELSEWHERE.
TUESDAY A TROUGH WILL PUSH ACROSS THE AREA. CLOUDS WILL BE ON THE
INCREASE WITH THE WAVE. MODELS DIFFER SLIGHT AS WEAK LOW TRACKS EAST
ACROSS THE SOUTHERN/CENTRAL PLAINS. MOISTURE LIMITED WITH THE SYSTEM
AND WILL KEEP MOST OF THE AREA DRY. DID RETAIN LOW POPS OVER THE FAR
SOUTHERN ZONES...AS MODELS DIFFER ON PATH AND QPF VALUES. ECMWF HAS
A MORE SOUTHERN TRACK OF THE MAIN LOW AND IS SLOWER...WITH ALL THE
QPF PRODUCED STAYING SOUTH OF THE CWA. GFS IS MORE PROGRESSIVE WITH
THE WAVE AND DOES PRODUCE SOME LIFT AND QPF OVER THE SOUTHERN CWA.
AND THE GEM IS STRONGER WITH NEARLY ALL OF THE CWA GETTING SOME
LIGHT PRECIP. HAVE GONE WITH THE MODEL BLEND...WITH THE FORECAST
ONLY HAVING SNOW IN THE SOUTHERN ZONES.
REST OF THE WEEK WILL SEE A RIDGE DEVELOPING OVER THE WEST...WITH
NORTHWEST FLOW ACROSS THE HIGH PLAINS. ARCTIC AIR TO REMAIN WELL TO
THE NORTHEAST WITH MORE SEASONALLY COOL TEMPS AND DRY CONDITIONS
EXPECTED. PENDING HOW FAST THE SNOW MELTS...MAY NEED SOME LOCALLY
DOWNWARD ADJUSTMENT OF HIGH AND LOW TEMPERATURES.
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.
&&
.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>010-023-094.
&&
$$
SHORT TERM/EXTENDED...JACOBS
AVIATION...CDC
AREA FORECAST DISCUSSION...CORRECTED TIME ON AVIATION DISCUSSION
NWS BINGHAMTON NY
1252 PM EST SAT FEB 4 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL CONTINUE A NORTHWEST FLOW OF SEASONABLY
COOL AIR OVER THE REGION. THIS AIR WILL HAVE SOME MOISTURE WITH
IT...SO CLOUDS AND EVEN A SPRINKLE OR FLURRY IS POSSIBLE FROM TIME
TO TIME.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...THOUGH WEATHER PATTERN IN GENERAL IS FAIRLY
BENIGN...THE STRATOCUMULUS DECK CONTINUES TO BE A REAL FORECAST
CHALLENGE THAT THE MODELS SIMPLY ARE NOT CAPTURING. THIS
MORNING...TENUOUS GEORGIAN BAY/LAKE HURON MOISTURE CONNECTION...IS
ALLOWING REGENERATION OF CLOUDS OVER EASTERN HALF OF LAKE ONTARIO.
THIS WILL ALLOW CLOUDS TO PERSIST ESPECIALLY ALONG SYRACUSE-
ONEONTA AXIS. LOW LEVEL VEERING WILL BREAK THE LAKE-TO-LAKE
CONNECTION BY MIDDAY...THOUGH LOW LEVEL MOISTURE
POOL/STRATOCUMULUS WILL SHIFT SOUTHWARD INTO WESTERN FINGER LAKES
BEFORE SCATTERING OUT...BEST RESOLVED BY 950-925MB RH FIELD IN THE
LATEST RUC MODEL RUN. SKY GRIDS HAVE BEEN UPDATED TO REFLECT
THESE TRENDS...WITH TWEAKS TO TEMPERATURE GRIDS AS WELL.
ALSO...INCLUDED SCATTERED FLURRIES UP TO ABOUT 1PM IN THE NARROW
AXIS OF LAKE-TO- LAKE CONNECTION...BEFORE IT BREAKS.
PREVIOUS DISCUSSION...WK WV PASSING ATTM WILL BE WELL OUT OF THE
AREA BY 12Z. WITH VERY MRGNL DELTA T OFF THE LAKE...LACK OF
SYNOPTIC ASSISTANCE SHD END THE FLURRY AND DRIZZLE ACTIVITY OVER
THE NRN ZONES. WHILE THE NRMLY MOIST NAM DRIES OUT THE LL AND WLD
LEAD TO CDY SKIES...HRRR CLINGS TO A LL CLD DECK IN THE FCST AREA
FOR MUCH OF THE DAY. GIVEN THE SEASON AND TRACK RECORD OF THE CRNT
SC DECK...XPCT MSTLY CDY SKIES TO CONT FOR MUCH OF THE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
QUIET WX PTRN CONTS IN THE SHRT TERM WITH A BROAD AREA OF HIPRES
OVER MUCH OF THE NRN PARTS OF THE US. THE FCST AREA...ON THE ERN
EDGE OF THE HI HAS A NW FLOW SFC AND ALOFT WITH WEAK WV DROPPING
INTO THE AREA FROM TIME TO TIME. DESPITE THE FLOW...HGTS RATHER
HIGH AND TEMPS ABV NRML SO VERY LIMITED CHANCE FOR ANY LE SNOW.
WV AND SFC TROF DROPS IN LATE TNGT AND EARLY SUN. ONCE
AGAIN...WITH VERY LTL COLD AIR LAKE RESPONSE WILL BE VERY LIMITED
WITH PERHAPS A SLGT CHANCE OF A LTL PCPN OVER THE NRN ZONES.
ANOTHER WV...MUCH WEAKER...PASSES MON WITH LTL EFFECT...OTR THAN
PERHAPS A FEW MORE CLDS.
MODEL GUID WAS IN GOOD AGREEMENT AND MADE FOR A RATHER PAINLESS
TEMPS FCST IN THE SHRT TERM. USED A BLEND OF GUID FOR TEMPS IN
GRIDS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
630 AM UPDATE...NO BIG CHANGES TO THE EXTENDED. MAIN ADDITION WAS
TO ADD A CHANCE FOR SNOW LATE WEDNESDAY AND ESPECIALLY WEDNESDAY
NIGHT AS BOTH THE EURO AND GFS SHOW SOME LIGHT SNOW MOVING
THROUGH. ASIDE FROM THAT STILL LOOKING AT MAINLY ABOVE NORMAL
TEMPS UNTIL SOMETIME NEXT WEEK WHEN IT LOOKS LIKE SOME COLDER AIR
MAY TRY TO MOVE OUR WAY. EVEN WITH THAT HOWEVER...THE 0Z
EURO...KEEPS THE MAIN CHUNK OF THE ARCTIC AIR WELL TO OUR NORTH
AND IT HAS DELAYED THE ONSET OF THIS COLDER AIR BY ANOTHER DAY OR
SO.
4PM FRIDAY UPDATE... ANOTHER MILD EXTENDED WITH A LACK
OF DECENT SNOW. MODELS AGREE ON THIS BUT NOT ON THE DETAILS. HPC
SIDING WITH ECMWF ENSEMBLE. A COLD FRONT COMES THROUGH TUESDAY
WITH SNOW SHOWERS FOLLOWED BY LAKE EFFECT SNOW TUESDAY NIGHT IN NW
FLOW. SFC HIGH PRESSURE BUILDS IN WEDNESDAY SHUTTING THIS DOWN.
MODELS DISAGREE ON THE END OF THE WEEK. SEVERAL SOUTHERN STREAM
WAVES GO THROUGH THE MID ATLANTIC STATES. SOME MODELS HAVE PRECIP
GETTING NORTH INTO THE AREA. BOTH THE EURO AND GFS HAVE A BROAD
UPPER LEVEL TROF OVER THE WESTERN GREAT LAKES SO COLD AIR STAYS
AWAY AND LOW LEVEL FLOW IS FRONT THE SOUTHWEST. NO LAKE EFFECT.
FRIDAY THIS TROF AND A COLD FRONT MOVES THROUGH BRINGING IN COLD
AIR FOR DAY 8 ON. SOME HOPE FOR COLDER WEATHER WEEK TWO AS THIS
LARGE UPPER LEVEL TROF SETS UP OVER THE NORTHEAST US SATURDAY AND
STAYS LONGER THAN 2 DAYS.
&&
.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
UPDATED AS OF 1245 PM SAT... VFR SHOULD BE THE PREVALENT CONDITION
THROUGH THE OVERNIGHT PD. N TO NW WINDS 5-10 KT THIS AFTN...WILL
DIMINISH THIS EVE.
SUN AM...A LWR CLOUD DECK WILL ENCROACH ON CNY/NE PA FROM NW TO
SE...AS A WEAK BNDRY PUSHES INTO THE RGN. MVFR IS EXPECTED TO
DEVELOP AT KSYR AND KRME...WITH THE POTENTIAL FOR SAME AT KITH AND
KBGM. WINDS WILL TURN NW AGAIN AT 5-10 KT.
.OUTLOOK...
SUN NGT-MON...MAINLY VFR.
MON NGT-TUE NGT...PSBL MVFR/IFR IN LAKE-EFFECT SHSN.
WED...MAINLY VFR...BUT MVFR POSSIBLE TOWARD EVENING IN LGT SNOW.
THU...MVFR/IFR PSBL IN LGT SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...HEDEN/TAC
AVIATION...HEDEN/MLJ
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
958 AM EST SAT FEB 4 2012
.SYNOPSIS...
WEAK HIGH PRESSURE WILL CONTINUE A NORTHWEST FLOW OF SEASONABLY
COOL AIR OVER THE REGION. THIS AIR WILL HAVE SOME MOISTURE WITH
IT...SO CLOUDS AND EVEN A SPRINKLE OR FLURRY IS POSSIBLE FROM TIME
TO TIME.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
10 AM UPDATE...THOUGH WEATHER PATTERN IN GENERAL IS FAIRLY
BENIGN...THE STRATOCUMULUS DECK CONTINUES TO BE A REAL FORECAST
CHALLENGE THAT THE MODELS SIMPLY ARE NOT CAPTURING. THIS
MORNING...TENUOUS GEORGIAN BAY/LAKE HURON MOISTURE CONNECTION...IS
ALLOWING REGENERATION OF CLOUDS OVER EASTERN HALF OF LAKE ONTARIO.
THIS WILL ALLOW CLOUDS TO PERSIST ESPECIALLY ALONG SYRACUSE-
ONEONTA AXIS. LOW LEVEL VEERING WILL BREAK THE LAKE-TO-LAKE
CONNECTION BY MIDDAY...THOUGH LOW LEVEL MOISTURE
POOL/STRATOCUMULUS WILL SHIFT SOUTHWARD INTO WESTERN FINGER LAKES
BEFORE SCATTERING OUT...BEST RESOLVED BY 950-925MB RH FIELD IN THE
LATEST RUC MODEL RUN. SKY GRIDS HAVE BEEN UPDATED TO REFLECT
THESE TRENDS...WITH TWEAKS TO TEMPERATURE GRIDS AS WELL.
ALSO...INCLUDED SCATTERED FLURRIES UP TO ABOUT 1PM IN THE NARROW
AXIS OF LAKE-TO- LAKE CONNECTION...BEFORE IT BREAKS.
PREVIOUS DISCUSSION...WK WV PASSING ATTM WILL BE WELL OUT OF THE
AREA BY 12Z. WITH VERY MRGNL DELTA T OFF THE LAKE...LACK OF
SYNOPTIC ASSISTANCE SHD END THE FLURRY AND DRIZZLE ACTIVITY OVER
THE NRN ZONES. WHILE THE NRMLY MOIST NAM DRIES OUT THE LL AND WLD
LEAD TO CDY SKIES...HRRR CLINGS TO A LL CLD DECK IN THE FCST AREA
FOR MUCH OF THE DAY. GIVEN THE SEASON AND TRACK RECORD OF THE CRNT
SC DECK...XPCT MSTLY CDY SKIES TO CONT FOR MUCH OF THE DAY.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/...
QUIET WX PTRN CONTS IN THE SHRT TERM WITH A BROAD AREA OF HIPRES
OVER MUCH OF THE NRN PARTS OF THE US. THE FCST AREA...ON THE ERN
EDGE OF THE HI HAS A NW FLOW SFC AND ALOFT WITH WEAK WV DROPPING
INTO THE AREA FROM TIME TO TIME. DESPITE THE FLOW...HGTS RATHER
HIGH AND TEMPS ABV NRML SO VERY LIMITED CHANCE FOR ANY LE SNOW.
WV AND SFC TROF DROPS IN LATE TNGT AND EARLY SUN. ONCE
AGAIN...WITH VERY LTL COLD AIR LAKE RESPONSE WILL BE VERY LIMITED
WITH PERHAPS A SLGT CHANCE OF A LTL PCPN OVER THE NRN ZONES.
ANOTHER WV...MUCH WEAKER...PASSES MON WITH LTL EFFECT...OTR THAN
PERHAPS A FEW MORE CLDS.
MODEL GUID WAS IN GOOD AGREEMENT AND MADE FOR A RATHER PAINLESS
TEMPS FCST IN THE SHRT TERM. USED A BLEND OF GUID FOR TEMPS IN
GRIDS.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
630 AM UPDATE...NO BIG CHANGES TO THE EXTENDED. MAIN ADDITION WAS
TO ADD A CHANCE FOR SNOW LATE WEDNESDAY AND ESPECIALLY WEDNESDAY
NIGHT AS BOTH THE EURO AND GFS SHOW SOME LIGHT SNOW MOVING
THROUGH. ASIDE FROM THAT STILL LOOKING AT MAINLY ABOVE NORMAL
TEMPS UNTIL SOMETIME NEXT WEEK WHEN IT LOOKS LIKE SOME COLDER AIR
MAY TRY TO MOVE OUR WAY. EVEN WITH THAT HOWEVER...THE 0Z
EURO...KEEPS THE MAIN CHUNK OF THE ARCTIC AIR WELL TO OUR NORTH
AND IT HAS DELAYED THE ONSET OF THIS COLDER AIR BY ANOTHER DAY OR
SO.
4PM FRIDAY UPDATE... ANOTHER MILD EXTENDED WITH A LACK
OF DECENT SNOW. MODELS AGREE ON THIS BUT NOT ON THE DETAILS. HPC
SIDING WITH ECMWF ENSEMBLE. A COLD FRONT COMES THROUGH TUESDAY
WITH SNOW SHOWERS FOLLOWED BY LAKE EFFECT SNOW TUESDAY NIGHT IN NW
FLOW. SFC HIGH PRESSURE BUILDS IN WEDNESDAY SHUTTING THIS DOWN.
MODELS DISAGREE ON THE END OF THE WEEK. SEVERAL SOUTHERN STREAM
WAVES GO THROUGH THE MID ATLANTIC STATES. SOME MODELS HAVE PRECIP
GETTING NORTH INTO THE AREA. BOTH THE EURO AND GFS HAVE A BROAD
UPPER LEVEL TROF OVER THE WESTERN GREAT LAKES SO COLD AIR STAYS
AWAY AND LOW LEVEL FLOW IS FRONT THE SOUTHWEST. NO LAKE EFFECT.
FRIDAY THIS TROF AND A COLD FRONT MOVES THROUGH BRINGING IN COLD
AIR FOR DAY 8 ON. SOME HOPE FOR COLDER WEATHER WEEK TWO AS THIS
LARGE UPPER LEVEL TROF SETS UP OVER THE NORTHEAST US SATURDAY AND
STAYS LONGER THAN 2 DAYS.
&&
.AVIATION /15Z SATURDAY THROUGH WEDNESDAY/...
630 AM UPDATE...
TRICKY FORECAST WITH THE NY TERMINALS BOUNCING BETWEEN MVFR AND
VFR QUITE A BIT THIS MORNING. FEEL VFR WILL CONTINUE TO PREVAIL AT
KRME/KELM AND KAVP WITH AN BKN/OVC DECK BETWEEN 3500 AND 5000 FEET
BEFORE SCATTERING OUT THIS AFTERNOON. ELSEWHERE...SOME MVFR CIGS
ARE MOST LIKELY TO LAST AT KITH WHERE THEY ARE CURRENTLY
PREVAILING. EVEN HERE THOUGH EXPECT A RETURN TO VFR TOWARD MID-
MORNING. AT KSYR AND KBGM...WITH A GOOD AMOUNT OF VARIANCE OVER
THE LAST FEW HOURS...THE CONFIDENCE IS ONLY HIGH ENOUGH IN MVFR
CIGS FOR A TEMPO GROUP OVER THE NEXT FEW HOURS. STILL FEEL THIS IS
WARRENTED HOWEVER BASED ON MVFR CIGS NEAR THE TERMINALS AT THIS
MOMENT.
VFR LATER TODAY THROUGH TONIGHT.
NORTHWEST WINDS THIS MORNING THROUGH THIS AFTERNOON AT 5 TO 10 KTS
BECOME CALM TONIGHT.
.OUTLOOK...
SUN...PSBL MVFR CIGS AND FLURRIES...MAINLY CENTRAL NY.
SUN NGT-MON...MAINLY VFR.
MON NGT-TUE NGT...PSBL MVFR/IFR IN LAKE-EFFECT SHSN.
WED...MAINLY VFR...BUT MVFR POSSIBLE TOWARD EVENING IN SNOW.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NY...NONE.
&&
$$
SYNOPSIS...DGM
NEAR TERM...DGM/MDP
SHORT TERM...DGM
LONG TERM...HEDEN/TAC
AVIATION...HEDEN
AREA FORECAST DISCUSSION
NWS BISMARCK ND
641 AM CST SAT FEB 4 2012
.DISCUSSION...
MAIN CONCERN TO STRATUS DECK FIRMLY ANCHORED OVER MUCH OF THE
NORTHERN PLAINS. A LONGER LOOP OF THE FOG IR IMAGERY SHOWS NORTH
EDGE OF THIS CLOUD MASS EDGING VERY SLOWLY TO THE SOUTH WHILE
EXPANSION CONTINUES WEST AND NORTHEAST. SHORT TERM MODELS NOT
RESOLVING THE LOW LEVEL CLOUDS WELL EXCEPT THE HRRR WHICH SHOWS
CONTINUATION OF THE CLOUDS THROUGH MUCH OF THE DAY NORTH AND
WEST...AND OVERNIGHT OVER THE SOUTH CENTRAL AND EAST CENTRAL. SOME
FREEZING DRIZZLE MIXED IN WITH SOME FLURRIES BUT NO ACCUMULATION
EXCEPT A SLIGHT SHEEN TO VEHICLES WHICH HAVE BEEN OUT DURING THE
NIGHT.
&&
.AVIATION...
LIFR AND IFR CONDITIONS EXPECTED THROUGH THE MOST OF THE TAF
PERIOD SOUTH CENTRAL AND EAST CENTRAL...WHILE IMPROVEMENT THIS
AFTERNOON WEST AND NORTH.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON CST /11 AM MST/ TODAY FOR
NDZ001>005-009>013-017>023-025-031>037-040>048-050-051.
&&
$$
SHORT TERM...HW
LONG TERM....HW
AVIATION...HW
AREA FORECAST DISCUSSION
NWS WILMINGTON OH
1240 AM EST SAT FEB 4 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL MOVE OFF TO THE EAST TONIGHT. A
LOW WILL TRACK JUST SOUTH OF THE AREA SATURDAY AND SATURDAY NIGHT
PROVIDING WET WEATHER. ANOTHER HIGH WILL BUILD IN FOR THE EARLY PART
OF NEXT WEEK.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
HAVE INCREASED THE CHANCES OF PRECIPITATION OVERNIGHT JUST
SLIGHTLY...OWING TO THE LEAD SHOWERS ALREADY MOVING THROUGH
INDIANA IN THE ISENTROPIC LIFT PATTERN. HIGH RESOLUTION MODELS ARE
DEPICTING THAT A BAND OF PRECIPITATION MAY MOVE THROUGH THE
NORTHWEST PART OF THE CWA BEFORE ANYWHERE ELSE (THUS...NOT A PURE
WEST TO EAST PROGRESSION). TRIED TO ACCOUNT FOR THIS IN THE
GRIDS...BEFORE INCREASING THINGS TO THE 80-100 POP RANGE IN THE SW
A BIT LATER IN THE MORNING.
THIS EVENT IS STILL ANTICIPATED TO BE PRIMARILY RAIN...BUT AN
ANALYSIS OF MODEL SOUNDINGS AND SURFACE TEMPS ACROSS THE NORTHERN
COUNTIES INDICATES THAT A MIX IS POSSIBLE. THERE ARE SOME SUB-
FREEZING DEWPOINTS IN THE NORTHERN COUPLE TIERS OF COUNTIES...WITH
TEMPERATURES DROPPING A BIT BELOW THE ANTICIPATED CURVE AND
NEARING FREEZING IN A FEW SPOTS AS WELL. THE ONLY MODEL SHOWING
MUCH OF A WARM BULGE ALOFT WAS THE 18Z NAM...WITH THE 00Z VERSION
AND RECENT RUC RUNS SHOWING JUST A SLIGHT WARM LAYER OR ISOTHERMAL
PROFILE IN THE LOWEST FEW THOUSAND FEET. SO WHILE SNOW IS
CERTAINLY POSSIBLE...AND WHILE FREEZING RAIN IS NOT FAVORED...A
BRIEF PERIOD OF SLEET AT THE ONSET OF PRECIPITATION IS A
LEGITIMATE POSSIBILITY. EITHER WAY...NO SIGNIFICANT IMPACTS ARE
EXPECTED.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH SUNDAY NIGHT/...
SOUTHERN STREAM UPPER LOW TO TRACK EAST AND WEAKEN AS IT MOVES
INTO THE MID MS VALLEY SAT/SAT NIGHT. AXIS OF FAVORABLE LOW LEVEL
FORCING TO DEVELOP ACRS ILN/S SRN FA SATURDAY AFTN. ASSOCIATED
WEAK SFC WAVE TO TRACK EAST FROM THE LWR MS VLY ON SAT THRU THE TN
VALLEY SATURDAY NIGHT. ILN/S SRN FA IN MOST FAVORABLE LOCATION FOR
PRECIP...WL CONTINUE CATEGORICAL POPS ACRS THE SRN HALF OF ILN/S
FA AND WILL BUMP UP POPS ACRS THE FAR NORTH INTO HIGH CHANCE
CATEGORY. EXPECT THE QPF FROM THIS EVENT RANGE FROM ONE QUARTER TO
ONE HALF INCH... AGAIN WITH THE BEST RAIN ACRS THE SOUTH. HAVE
TREND SATURDAYS HIGHS ON THE WARM SIDE OF GUIDANCE TEMPS.
NUMERICAL MODEL SOLNS INDICATING THAT THE SRN STREAM UPPER LOW WILL
OPEN UP AND PHASE WITH NORTHERN STREAM TROF DROPPING SE THRU THE
OHIO VALLEY EARLY SUNDAY. SOME TIMING DIFFERENCES EXIST WITH THE
ECMWF SOLN BEING THE MOST PROGRESSIVE AND THE NAM SOLN BEING THE
SLOWEST. HAVE TRENDED FORECAST TOWARD THE FASTER SOLN AND WILL
LINGER VERY LOW CHANCE POPS ACROSS THE FAR SOUTH IN RESPONSE TO THIS
TROF. GIVEN THE CAA HAVE ALLOWED FOR A VERY BRIEF MIX ON THE NRN
FRINGE OF THE PRECIP VERY LATE SATURDAY NIGHT AND EARLY SUNDAY.
HAVE TRENDED SUNDAYS HIGHS ON THE WARM SIDE OF GUIDANCE ENVELOPE.
IN NORTHERN FLOW...SURFACE RIDGE TO BUILD IN SUNDAY INTO SUNDAY
AFTERNOON INTO SUNDAY NIGHT. UNDER MAINLY CLEAR SKIES SUNDAY NIGHT
WITH LOWS GENERALLY RANGING FROM THE MID 20S TO THE UPPER 20S.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
DRY WEATHER IS INDICATED MONDAY THROUGH WEDNESDAY. SURFACE HIGH
PRESSURE STRETCHING FROM WEST TO EAST ALONG A ZONAL UPPER FLOW WILL
BE MOVING THROUGH ON MONDAY. A MID LEVEL SHORT WAVE AND WEAKENING
SURFACE TROUGH FOR MONDAY NIGHT WILL LACK AMPLE MOISTURE SO KEPT
FORECAST DRY. TUESDAY AND WEDNESDAY WILL HAVE A SHEARED SHORT WAVE
FOLLOWED BY A SURFACE HIGH...SO DRY CONDITIONS ARE EXPECTED TO
PERSIST.
THERE IS MORE UNCERTAINTY CONCERNING THURSDAY. LATEST RUN OF ECMWF
HAS A BROAD AREA OF PRECIPITATION EXTENDING NORTH TO ILN FROM AN
AREA OF LOW PRESSURE NEAR THE GULF COAST. KEPT POPS BELOW 25 PERCENT
AND WILL LET LATER SHIFTS EVALUATE FUTURE MODEL RUNS FOR A POSSIBLE
INCREASE IN POPS. FOR NEXT FRIDAY...SNOW SHOWERS SHOULD STAY
CONFINED TO THE GREAT LAKES SO WENT WITH POPS OF 20 OR LESS.
LOOK FOR ABOVE NORMAL TEMPERATURES MONDAY AND TUESDAY WITH HIGHS
MAINLY IN THE 40S. HIGHS ARE FORECAST TO SLIP TOWARD NORMAL READINGS
IN THE UPPER 30S TO LOWER 40S WEDNESDAY THROUGH FRIDAY. HOWEVER...IF
THE CURRENT RUN OF THE ECMWF VERIFIES...READINGS MAY BE LOWER DURING
THAT TIME PERIOD.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
A LOW PRESSURE SYSTEM WILL APPROACH THE AREA OVERNIGHT AND MOVE
SOUTH OF THE TAF SITES SATURDAY INTO SATURDAY NIGHT. SOME LIGHT
PRECIPITATION IS OCCURRING ACROSS INDIANA HOWEVER NOT ALL OF THE
RETURNS ON RADAR ARE REACHING THE GROUND. MORE WIDESPREAD RAIN IS
OCCURRING ACROSS IL. RAIN WILL GRADUALLY MOVE INTO THE TAF SITES
LATE DURING THE OVERNIGHT HOURS AND INTO THE DAY ON SATURDAY.
PRECIPITATION WILL BECOME MORE WIDESPREAD ACROSS THE TAF SITES
DURING THE DAY ON SATURDAY. VSBYS WILL GENERALLY BE MVFR WITH THE
PRECIPITATION HOWEVER A BRIEF PERIOD OF IFR VSBYS CANNOT BE RULED
OUT. CIGS WILL GRADUALLY DECREASE ON SATURDAY AS WELL. IFR CIGS
WILL BE POSSIBLE ACROSS MOST OF THE AREA TAF SITES EXCEPT FOR KCMH
AND KLCK SATURDAY EVENING INTO SATURDAY NIGHT AS THE AREA OF LOW
PRESSURE MOVES JUST SOUTH OF THE TAF SITES.
OUTLOOK...MVFR/IFR CEILINGS LIKELY SATURDAY NIGHT INTO SUNDAY
MORNING.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
KY...NONE.
IN...NONE.
&&
$$
SYNOPSIS...AR
NEAR TERM...HATZOS
SHORT TERM...AR
LONG TERM...CONIGLIO
AVIATION...NOVAK
AREA FORECAST DISCUSSION
NWS CLEVELAND OH
1144 PM EST FRI FEB 3 2012
.SYNOPSIS...
HIGH PRESSURE OVER THE REGION WILL DRIFT TO THE EAST COAST
OVERNIGHT BUT A WEAK RIDGE WILL REMAIN EXTENDED ACROSS THE LOWER
GREAT LAKES. LOW PRESSURE OVER OKLAHOMA WILL MOVE EAST ACROSS THE
TENNESSEE VALLEY SATURDAY AFTERNOON AND NIGHT. HIGH PRESSURE WILL
BUILD BACK ACROSS THE REGION FROM THE CENTRAL PLAINS ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
IN COORDINATION WITH LOCAL STAFF AND NEARBY OFFICES...DECIDED TO
NUDGE PRECIPITATION A BIT FURTHER NORTH. LATEST OBSERVATIONS ARE
SHOWING THE PRECIPITATION AS FAR NORTH AS IOWA AT THIS TIME AND
GOES ALONG WELL WITH THE LATEST HRRR MODEL. SCARY PART IS THE HRRR
TAKES THE PRECIPITATION OVER THE ENTIRE FORECAST AREA BY 12Z IN
THE MORNING. WILL ERR ON THE SIDE OF JUST NUDGING PRECIPITATION
FOR NOW AND MENTION TO MIDNIGHT SHIFT THAT PRECIPITATION MAY BE
FURTHER NORTH THAN FORECAST BY MORNING.
PRECIPITATION IN THE SOUTH SHOULD START OUT AS SNOW AND BECOME
MIXED WITH RAIN AT TIMES THEN ALL RAIN TOMORROW MORNING.
TEMPERATURES ACROSS THE AREA CONTINUE TO DROP IN COOL LIGHT
NORTHERLY FLOW AND STILL EXPECTING LOWER 30S WEST AND UPPER 20S
EAST.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY NIGHT/...
MAIN FORECAST ISSUE FOR THE SHORT TERM IS THE LOW MOVING ACROSS
THE TENNESSEE VALLEY SATURDAY AND SATURDAY NIGHT. MODELS BRING
MOISTURE INTO THE AREA DURING THE PERIOD AND THE QUESTION WOULD BE
HOW FAR NORTH ASSOCIATED PRECIP MAKES IT INTO THE AREA. USUALLY
THESE SYSTEMS DRAG DRIER AIR INTO THE AREA FROM THE NORTH AND
NORTHEAST WHICH TENDS TO LIMIT PRECIP REACHING THE GROUND ACROSS
THE AREA. BELIEVE THAT WILL OCCUR AND HAVE LIMITED ANY PRECIP TO
THE FAR SOUTHERN TIER OF COUNTIES SATURDAY AND SATURDAY NIGHT.
SUNDAY...DEEP MOISTURE DROPS SOUTHEAST OF THE AREA AND ANOTHER
UPPER TROF DIGS ACROSS THE EASTERN LAKES. EXPECT THIS TO BRING SO
INCREASE ON MOISTURE BUT STILL...AIRMASS REMAINS FAIRLY DRY AND
850MB TEMPS STILL ON THE MILD SIDE SO EXPECT DRY MILD CONDITIONS
SUNDAY AND MONDAY.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
A COLD FRONT WILL SAG ACROSS THE REGION TUESDAY. THERE COULD BE A
FEW SNOW SHOWERS OFF OF LAKE ERIE IN ITS WAKE BUT IT WILL BE VERY
SHORT LIVED. HIGH PRESSURE WILL THEN BUILD IN FOR WEDNESDAY BUT
BEYOND THIS POINT MODELS BEGIN TO DIVERGE. BOTH HAVE A TROUGH
DEVELOPING OVER THE EASTERN 2/3 OF THE US BUT HAVE VERY DIFFERENT
SCENARIOS ON THE STRENGTH OF JET ENERGY MOVING THROUGH THE FLOW. AT
THIS POINT WE HAVE LEANED ON AN HPC/ECMWF BLEND FOR THURSDAY INTO
FRIDAY.
HIGH TEMPERATURES THROUGH THE EXTENDED LOOK LIKE THEY WILL REMAIN
NEAR TO SLIGHTLY ABOVE AVERAGE.
&&
.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
THE LATEST MODEL RUNS SEEMS TO AGREE THAT SOME SNOW AND RAIN SHOULD
SPREAD ESE ACROSS FDY AND MFD BETWEEN 11Z AND 15Z THEN GET PUSHED
SOUTH OF THE AREA BY LATE IN THE DAY SAT. WILL LOWER VSBY AND CIGS A
LITTLE MORE FOR THE PRECIP.
PATCHY MVFR CLOUDS AROUND LAKE ERIE SHOULD EVENTUALLY DISSIPATE
LATER TONIGHT INTO THE FIRST FEW HOURS OF DAYLIGHT SAT BUT FOR THE
TIME BEING WILL BE PROBLEMATIC FOR TOL...CLE AND ERI.
WIDESPREAD VFR SHOULD TAKE OVER SAT EVENING AS DRIER AIR IS PULLED
SOUTH OVER THE WHOLE AREA.
.OUTLOOK...NON VFR POSSIBLE ON MONDAY AND TUE.
&&
.MARINE...
HIGH PRESSURE WILL REMAIN OVER THE LAKE TONIGHT AND SATURDAY. LOW
PRESSURE WILL TRACK WELL SOUTH OF THE LAKE BUT SHOULDN/T POSE ANY
PROBLEMS FOR THE LAKE ITSELF DURING SATURDAY. MEANWHILE...THE MORE
SIGNIFICANT FOCUS WILL BE ON AN UPPER TROUGH THAT WILL MOVE ACROSS
THE LAKE SATURDAY NIGHT AND SUNDAY. THIS WEAK UPPER TROUGH IS NOT
EXPECTED TO BRING HEADLINE CONDITIONS TO THE LAKE OVER THE
WEEKEND...BUT WILL SHIFT WINDS AROUND. HIGH PRESSURE WILL BUILD BACK
OVER THE LAKE MONDAY...THEN ANOTHER COLD FRONT IS EXPECTED TO CROSS
THE LAKE TUESDAY...FOLLOWED BY ANOTHER ROUND OF HIGH PRESSURE BY THE
MIDDLE OF NEXT WEEK.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...NONE.
PA...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...TK
NEAR TERM...LOMBARDY
SHORT TERM...TK
LONG TERM...MULLEN
AVIATION...ADAMS
MARINE...ABE
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
900 PM CST SUN FEB 5 2012
.DISCUSSION...
TRICKY FORECAST TONIGHT CONCERNING LOW TEMPERATURES. STRATUS IN NW
IA IS BEGINNING TO OOZE BACK NORTHWARD AS WINDS JUST OFF THE SURFACE
SHIFT TO THE SSW. IT APPEARS AT THE MOMENT...THAT AN APPROXIMATE
LINE FROM YANKTON...TO SIOUX FALLS/DELL RAPIDS...TO EVENTUALLY
WINDOM MN WILL BE ON THE EDGE OF THE STRATUS. THEREFORE LOW
TEMPERATURES IN THAT CORRIDOR WILL BE GREATLY INFLUENCED UP OR DOWN
BY THE CLOUDS. FOR NOW...LOWERED THE MIN TEMPERATURES AT SIOUX FALLS
AND YANKTON A LITTLE BIT...SINCE CURRENT READINGS ARE ALREADY NEAR
LOWS. ALSO LOWERED READINGS AT BROOKINGS AND HURON WHO COMMONLY
RADIATE OUT EVEN WITH A LIGHT SOUTH WIND. RAISED TEMPERATURES A TAD
IN NW IA DEEP INTO THE STRATUS...AS THAT AREA HAS NO CHANCE OF
CLEARING OUT. OTHERWISE...THE AREAS OF FOG WE HAVE GOING STILL LOOKS
VERY GOOD FOR THE AREA COVERED...PROJECTING THE STRATUS NORTHWARD.
&&
.PREV 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.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS NASHVILLE TN
1133 PM CST FRI FEB 3 2012
.UPDATE...FOR 06Z AVIATION FORECAST
&&
.AVIATION...
CLOUDY SKIES ACROSS THE REGION WILL CONTINUE TO LOWER INTO MVFR CATEGORY
WITH THE ON-SET OF LIGHT RAIN BETWEEN 10 AND 12Z. SURFACE LOW AT 06Z
OVER JOPLIN MISSOURI WITH A WARM FRONT DRAPED DOWN THROUGH ARKANSAS
INTO SOUTHERN MISSISSIPPI. WARM FRONT WILL LIFT NORTHWARD LATER TONIGHT
AND INTO THE TENNESSEE VALLEY ON SATURDAY. LAMP GUIDANCE KEEPS LIGHT
RAIN ON-GOING THROUGHOUT THE DAY ON SATURDAY UNTIL AROUND 00Z AT
BNA AND 03Z AT CSV AS COLD FRONT SWEEPS EAST. HOWEVER WARM FRONT WILL
BE NORTH OF MIDDLE TENNESSEE BY EARLY AFTERNOON ON SATURDAY AND
MID STATE WILL THEN BE IN WARM SECTOR FOR A PERIOD OF TIME SATURDAY
AFTERNOON. WE COULD SEE A BREAK IN THE RAIN AND A LIFTING IN THE
CEILING AT SOME POINT SATURDAY AFTERNOON BEFORE COLD FRONT ARRIVES
FROM THE WEST.
BOYD
&&
.PREV DISCUSSION... /ISSUED 903 PM CST FRI FEB 3 2012/
UPDATE...
RADAR IMAGERY THIS EVENING SHOWS A FEW LIGHT RAIN SHOWERS AND
SPRINKLES OVER PARTS OF THE MID STATE...BUT SURFACE AIRMASS
REMAINS RATHER DRY AND MOST RAINFALL IS TO OUR SOUTH IN ALABAMA.
LATEST HRRR RUN INDICATES THESE SHOWERS WILL CONTINUE SPREADING
NORTHEAST ACROSS THE MID STATE OVERNIGHT WITH SOME ADDITIONAL
SHOWER DEVELOPMENT BEHIND CURRENT ACTIVITY AS ATMOSPHERE CONTINUES
TO MOISTEN...BUT OVERALL COVERAGE LOOKS TO REMAIN SPARSE. HAVE
LOWERED POPS FOR THE EVENING HOURS SIGNIFICANTLY BASED ON THESE
REASONS. HRRR ALSO SHOWS CONVECTION OVER ARKANSAS MOVING EASTWARD
AND ENTERING THE WESTERN CWA BETWEEN 10-12Z...THEN SPREADING
THROUGHOUT THE AREA DURING THE DAY ON SATURDAY. THUS WILL MAINTAIN
CATEGORICAL POPS FOR THE MIDNIGHT TO SUNRISE PERIOD...ALTHOUGH
THESE RAIN CHANCES ARE ON THE HIGH SIDE AS BULK OF PRECIP WILL
MAINLY BE VERY LATE TONIGHT OVER WESTERN ZONES. AND SPEAKING OF
SATURDAY...LATEST NAM FORECAST SOUNDINGS INDICATE SOME WEAK
INSTABILITY ALONG WITH MODEST SHEAR ON SATURDAY...SO A FEW STRONG
STORMS CANNOT BE RULED OUT.
PREV DISCUSSION... /ISSUED 640 PM CST FRI FEB 3 2012/
UPDATE...FOR 00Z AVIATION FORECAST
AVIATION...
MSAS HAS SURFACE LOW CENTERED SOUTHERN OKLAHOMA AT 00Z WITH A WARM
FRONT DRAPED DOWN ACROSS SOUTHERN ARKANSAS INTO MISSISSIPPI AND
SOUTHERN ALABAMA. THUNDERSTORMS HAVE BEEN CONFINED TO EASTERN
OKLAHOMA AND WESTERN ARKANSAS WITH A STROKE OR TWO OF LIGHTNING
ALONG THE WARM FRONT DOWN IN SOUTHERN MISSISSIPPI. EXPECT FLYING
CONDITIONS TO DETERIORATE AFTER MIDNIGHT AND DOWN TO MVFR BY 08Z AT
BNA AND AROUND 09Z AT CSV. THEN IFR BOTH BNA AND CSV BY DAYBREAK
SATURDAY. LAMP GUIDANCE KEEPS IFR CONDITIONS AT BOTH BNA AND CSV
DURING THE DAY ON SATURDAY SO DID NOT DIFFER. THUNDER CHANCES LOOK
MINIMAL BOTH BNA AND CSV NEXT 24 HOURS.
BOYD
PREV DISCUSSION... /ISSUED 321 PM CST FRI FEB 3 2012/
DISCUSSION...
CLOUDS HAVE NOW OVERSPREAD THE MID STATE AND THE RAINFALL IS AS FAR
EAST AS FAR WESTERN TN. STORM SYSTEM THAT IS RESPONSIBLE FOR ALL OF
THIS IS LOCATED BACK OVER OK AT THIS HOUR. GOOD UPPER LEVEL ENERGY
FEED IS EVIDENT WITH GOOD DIRECTIONAL CONVERGENCE AS WELL.
THE TREND STILL REMAINS THAT THE DEEPER MOISTURE WILL SPREAD ACROSS
THE MID STATE TONIGHT AND INTO SATURDAY. THUS...CATEGORICAL POPS ARE
NEEDED. HOWEVER...PROJECTED RAINFALL AMOUNTS FOR MIDDLE TN DO NOT
LOOK THAT APPRECIABLE. IN FACT...ESTIMATE QPF AMOUNTS WILL AMOUNT TO
ONE HALF TO 1 INCH AT THE MOST. THE REASON FOR THIS IS BECAUSE
THE UPPER ENERGY FEED IS EXPECTED TO DECREASE OVER THE NEXT 24 TO
36 HOURS. AS THIS HAPPENS...THE STRENGTH OF THE SFC LOW WILL
DECREASE THEREBY REDUCING THE SFC CONVERGENCE.
FOR THE FCST...AGAIN...CATEGORICAL POPS TO BE INCLUDED TONIGHT AND
SATURDAY. SHOWALTERS APPROACH ZERO ALONG WITH SOME LOW LEVEL
CONVECTIVE POT ENERGY. WILL THEREFORE INCLUDE A SLIGHT CHANCE OR
CHC OF T ALONG WITH THE SHOWERS.
ASSOCIATED FROPA TO OCCUR SAT NT WITH A CHANCE OF SHOWERS
CONTINUING BEHIND IT AS WEAK PVA REMAINS IN PLACE....SLIGHTLY COOLER
BEHIND THE FRONT.
FOR THE NEAR TERM TEMPS. ABOVE NORMAL VALUES TO CONTINUE. WILL
UNDERCUT BY A FEW DEGREES FOR PDS 4 AND 5.
IN THE EXT FCST...TEMPS TO REMAIN A LITTLE ABOVE NORMAL WITH MOSTLY
DRY WEATHER EXPECTED THROUGH THURSDAY. GFS IS THE ODD MODEL OUT AS
IT ATTEMPTS TO BRING A GULF LOW NORTHEASTWARD ACROSS SRN GA. WILL GO
AHEAD AND INCLUDE A LOW CHANCE OF RAIN BUT I WILL CERTAINLY UNDERCUT
THE MEX VALUES.
FOR THE LONG TERM TEMPS...WILL GENERALLY UNDERCUT THE MEX NUMBERS BY
A DEGREE OR TWO THROUGH THE PERIOD. TEMPS TO REMAIN ABOUT 3-7
DEGREES ABOVE NORMAL.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
01
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
749 PM CST SUN FEB 5 2012
.DISCUSSION...WITH THE EXCEPTION OF AN ISOLATED SHOWER EXITING
VICTORIA COUNTY...SHOWER ACTIVITY HAS ENDED ACROSS THE CWA. THERE
IS ONE MORE DISTURBANCE SHOWN BY MODELS TO COME OUT OF MEXICO AND
ACROSS SOUTH TEXAS OVERNIGHT AND MONDAY MORNING. HOWEVER...COMPARED
TO LAST NIGHT H85 MOISTURE FLUX IS MUCH LESS TONIGHT...JET STREAK
WEAKER AND ELEVATED LAPSE RATES ABOVE H75 LESS STEEP. WILL KEEP
ONLY A 10 POP FOR ISOLATED ELEVATED SHOWERS OVERNIGHT INTO MONDAY
MORNING...QPF AND COVERAGE NOTHING LIKE LAST NIGHT. OTHERWISE...
ONLY VERY MINOR CHANGES MADE TO HOURLY GRIDS TO RE-ESTABLISH
TRENDS.
&&
.PREV DISCUSSION... /ISSUED 538 PM CST SUN FEB 5 2012/
DISCUSSION...NOTE AVIATION DISCCUSION BELOW.
AVIATION...GENERALLY VFR CEILINGS (3500-5000FT) ARE EXPECTED
DURING THE TAF PERIOD. BRIEF FOG WITH MVFR VISIBILITIES MAY
OCCUR...DRG THE 10-14Z MONDAY PERIOD...OVER LOCATIONS THAT
RECEIVED COPIOUS RAINFALL LAST NIGHT. PATCHY LIGHT RAIN OR ISOLD
SHOWERS MAY OCCUR TNGT YET WITH CONDITIONS IMPROVING FROM WEST TO
EAST. GENERALLY LGT TO OCCASIONALLY MODERATE NORTH WIND DRG THE
PERIOD.
PREV DISCUSSION... /ISSUED 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 / 10 10 10 20 30
VICTORIA 42 58 42 64 46 / 10 10 10 20 20
LAREDO 46 63 48 66 52 / 10 10 10 10 30
ALICE 43 60 43 65 49 / 10 10 10 20 30
ROCKPORT 46 59 51 66 50 / 10 10 10 20 30
COTULLA 43 60 42 64 48 / 10 10 10 10 20
KINGSVILLE 43 60 44 66 50 / 10 10 10 20 30
NAVY CORPUS 48 60 48 67 50 / 10 10 10 20 30
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY UNTIL MIDNIGHT CST TONIGHT FOR THE
FOLLOWING ZONES: 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.
&&
$$
JR/76...SHORT TERM
AREA FORECAST DISCUSSION
NWS CORPUS CHRISTI TX
538 PM CST SUN FEB 5 2012
.DISCUSSION...NOTE AVIATION DISCCUSION BELOW.
&&
.AVIATION...GENERALLY VFR CEILINGS (3500-5000FT) ARE EXPECTED
DURING THE TAF PERIOD. BRIEF FOG WITH MVFR VISIBILITIES MAY
OCCUR...DRG THE 10-14Z MONDAY PERIOD...OVER LOCATIONS THAT
RECEIVED COPIOUS RAINFALL LAST NIGHT. PATCHY LIGHT RAIN OR ISOLD
SHOWERS MAY OCCUR TNGT YET WITH CONDITIONS IMPROVING FROM WEST TO
EAST. GENERALLY LGT TO OCCASIONALLY MODERATE NORTH WIND DRG THE
PERIOD.
&&
.PREV DISCUSSION... /ISSUED 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.
&&
$$
WC/87...SHORT TERM
AREA FORECAST DISCUSSION
NWS FORT WORTH TX
1127 AM CST SAT FEB 4 2012
.AVIATION...
GFS/NAM AND MOS HAVE NO CLUE THAT THE NORTH WINDS ARE BLOWING OFF
A DEEP SNOW PACK IN KS/CO..AND SO THEY ARE FORECASTING VFR THRU
PERIOD. SATELLITE SHOWS MVFR CLOUDS ALREADY CROSSING RED RIVER.
LATEST HRRR HAS STARTED TO GET THE IDEA AND BRINGS SCT MVFR
CLOUDS ACROSS METROPLEX THIS AFTN. I WILL FORECAST SCT025 THIS
AFTERNOON AS DAYTIME WARMING WILL LIKELY HELP BREAK UP THE
LAYER...BUT PATCHY BRIEF BKN AREAS ARE POSSIBLE. AFTER
SUNSET...AS BOUNDARY LAYER COOLS...CLOUDS SHOULD THICKEN AND 025
CIGS ARE PROBABLE. HAVE ADDED THEM TO THE METROPLEX TAFS THROUGH
MID MORNING SUNDAY.
WITH WACO AT A LOWER ELEVATION...HAVE FORECAST CIGS TONIGHT TO BE
A BIT HIGHER. 84
&&
.UPDATE...
EXCEPT FOR A FEW SPOTTY SHOWERS IN THE SOUTHEAST...ALL
PRECIPITATION HAS EXITED NORTH TEXAS LATE THIS MORNING. SCATTERED
TO BROKEN MID AND UPPER LEVEL CLOUDS WILL LINGER OVER NORTH TEXAS
THROUGH THE DAY AND EVEN SOME LOWER CLOUDS SHOULD CROSS THE RED
RIVER THIS AFTERNOON. AFTERNOON HIGH TEMPERATURES WILL BE TRICKY
DUE TO THE NUMEROUS BREAKS IN THE CLOUDS AND CONTINUED COLD AIR
ADVECTION BEHIND YESTERDAYS COLD FRONT. FOR NOW THE CURRENT
TEMPERATURE FORECAST IS IN PRETTY GOOD SHAPE BUT WE WILL MAKE A
FEW MINOR ADJUSTMENTS BASED ON CURRENT TRENDS. WE WILL ALSO ADJUST
THE HOURLY CLOUD AND WIND GRIDS. 79
&&
.PREV DISCUSSION... /ISSUED 345 AM CST SAT FEB 4 2012/
A COLD FRONT HAD EXITED THE SOUTHEASTERN PART OF NORTH TEXAS AS
OF 3 AM...EXTENDING SOUTHEAST OF A PARIS...PALESTINE...COLLEGE
STATION...SAN MARCOS LINE. THE MAIN BAND OF SHOWERS AND
THUNDERSTORMS EXTENDED SOUTHEAST OF AN ATHENS TO GEORGETOWN
LINE...WITH SOME LINGERING SHOWERS EXTENDING BACK TO JUST EAST OF
A KILLEEN...DALLAS...PARIS LINE. EXPECT THE RAIN TO END BY MID
MORNING ACROSS NORTH TEXAS. AN UPPER LEVEL LOW OVER NORTH CENTRAL
KANSAS WILL MOVE EAST INTO THE OHIO VALLEY TODAY.
A WEAK UPPER LEVEL DISTURBANCE WILL SLIDE ACROSS SOUTH TEXAS
SUNDAY AND SUNDAY NIGHT...BELIEVE THAT PRECIPITATION FROM THIS
SYSTEM WILL BE CONFINED TO SOUTH TEXAS...SO HAVE LOWERED THE POPS
TO 10 PERCENT AND REMOVED MENTION OF SHOWERS ACROSS OUR
SOUTHEASTERN ZONES. WE WILL SEE COOL...NEAR SEASONAL
NORMAL...WEATHER FOR MOST OF THE NEXT WEEK. AS A SHORTWAVE MOVES
ACROSS THE PLAINS TUESDAY THERE COULD BE SOME LOW RAIN
CHANCES...AT THIS TIME HAVE JUST PLACED 20 PERCENT POPS ACROSS
THE EASTERNMOST ZONES. AN UPPER LEVEL SYSTEM WILL DIG SOUTH TO
OFF THE CENTRAL CALIFORNIA COAST BY TUESDAY NIGHT...AND THEN INTO
THE SOUTHERN BAJA CALIFORNIA BY THURSDAY NIGHT. THIS SYSTEM
SHOULD THEN MOVE EASTWARD DURING THE WEEKEND. THIS WILL RESULT IN
DRY WEATHER CONTINUING ACROSS MOST OF NORTH TEXAS THROUGH THE END
OF THE FORECAST PERIOD. 58
&&
.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX 59 36 51 35 54 / 5 0 5 5 5
WACO, TX 61 38 53 34 56 / 10 5 10 5 5
PARIS, TX 60 35 51 33 55 / 5 5 5 5 5
DENTON, TX 57 33 49 32 53 / 5 0 5 0 5
MCKINNEY, TX 60 35 50 33 54 / 5 0 5 5 5
DALLAS, TX 61 37 51 36 56 / 5 5 5 5 5
TERRELL, TX 61 36 51 34 55 / 5 5 5 5 5
CORSICANA, TX 60 38 53 36 56 / 10 5 10 5 5
TEMPLE, TX 61 39 53 35 56 / 10 5 10 5 5
MINERAL WELLS, TX 59 32 51 31 54 / 5 0 5 0 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
600 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...TONIGHT AND MONDAY
600 PM CST SUN FEB 5 2012
CHALLENGES PERSIST THIS TAF PERIOD WITH STRATUS DECK OF IFR/LIFR
CEILINGS CURRENTLY ACROSS SOUTHERN MINNESOTA AND MUCH OF IOWA.
ACROSS WISCONSIN...CEILINGS ARE SLIGHTLY HIGHER...MAINLY IN THE
800 TO 1500 FT RANGE. AFTERNOON INSOLATION HELPED MIX OUT PARTS OF
STATUS...BUT EROSION AND PROGRESSION HAS SLOWED WITH LOSS OF
DIURNAL MIXING.
PER THE HRRR AND RUC NEAR-TERM GUIDANCE...DO NOT EXPECT THE CURRENT
CLEARING ACROSS SOUTHWEST MINNESOTA TO REACH KRST OR KLSE. THUS WILL
KEEP PESSIMISTIC FORECAST TRENDS THROUGH MID MORNING MONDAY AT
BOTH TAF SITES. SIMILAR TO SATURDAY EVENING...CURRENT VISIBILITIES
AT KRST HAVE DROPPED TO LESS THAN 1 SM BUT EXPECTING THIS TO IMPROVE
TO THE 3 TO 4 SM RANGE BY 02Z AS WESTERLY WINDS INCREASE...SCOURING
OUT LOCAL FOG. CEILINGS WILL REMAIN IN LIFR /200 TO 400 FT /
THROUGH 16Z MONDAY.
AT KLSE...CURRENT MVFR CEILINGS ARE EXPECTED TO DROP DOWN TO IFR
OVERNIGHT AND VISIBILITIES SHOULD REDUCE TO AROUND 3 SM AROUND 09Z.
AN APPROACHING COLD FRONT FROM THE NORTHWEST WILL GIVE THE STRATUS
THE PUSH TO COMPLETELY ERODE BY MID DAY. SOME HIGH LEVEL CLOUDS
WILL STREAM IN FROM THE NORTH IN THE AFTERNOON ASSOCIATED INITIALLY
WITH THE NEXT SHORTWAVE.
LOOKING AHEAD...LOW CLOUDS/STRATUS IS EXPECTED AFTER 00Z TUESDAY
ASSOCIATED WITH POST-FRONTAL COLD AIR ADVECTION.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
340 PM CST SUN FEB 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...TAYLOR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
342 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...THROUGH 18Z SUNDAY
1146 AM CST SAT FEB 4 2012
A VERY DIFFICULT AVIATION FORECAST...EVEN FOR THE NEXT 6 TO 12
HOURS...DUE MOSTLY TO THE PRESENCE OF A VLIFR/LIFR STRATUS DECK
OVER SOUTH CENTRAL MINNESOTA AND THE EASTERN DAKOTAS. UNDERNEATH
THE STRATUS DECK...VISIBILITIES RANGE FROM LIFR TO IFR WITH SLOW
IMPROVEMENT OCCURRING THROUGH THE MORNING. SUNSHINE APPEARS TO
HAVE STALLED THE EASTWARD MOVEMENT OF THE STRATUS TO THE DODGE
CENTER MN AREA. QUESTION WITH THE STRATUS DECK OVER SOUTH CENTRAL
MINNESOTA IS HOW MUCH MIXES/CLEARS OUT DURING THE AFTERNOON.
SCENARIO 1...IF IT MOST OF IT CLEARS OUT...THEN WE WAIT FOR A
10-15 KT NORTHWEST WIND SITTING ABOVE THE SURFACE TO BRING THE
STRATUS OVER THE EASTERN DAKOTAS INTO THE TAF SITES. SCENARIO
2...IF SOME OF THE STRATUS STILL EXISTS BY THE TIME THE SUN STARTS
TO SET...THE NORTHWEST WIND WOULD BRING IT INTO THE TAF SITES
QUICKER. TRIED TO PLAY A SEMI-COMPROMISE APPROACH...BRINGING THE
STRATUS INTO KRST AROUND 03Z AND KLSE AT 04Z. DID THROW IN A VCFG
AND SCT002 AT KRST FROM 21-03Z IN CASE IT COMES IN FASTER.
ANTICIPATING CEILINGS TO DROP TO LIFR-IFR. VISIBILITIES ARE LIKELY
TO COME DOWN TOO...BUT THE WIND MAY ONLY ALLOW THEM TO DROP TO
IFR-MVFR. AFTER A FEW HOURS...INDICATIONS ARE THAT THE WIND SHOULD
HELP TO BRING CEILINGS UP A FEW HUNDRED FEET. LATE SUNDAY
MORNING...HEATING MAY ALLOW THE STRATUS AND BR TO DISSIPATE...BUT
CONFIDENCE IS LOW BEING AT THE END OF THE TAF PERIOD AND MODEL
HANDLING OF THE STRATUS LATELY. THEREFORE...HAVE NOT SHOWN THIS
CLEARING YET.
NEEDLESS TO SAY...THE AVIATION FORECAST IS LOW CONFIDENCE. BIG
THING RIGHT NOW IS MONITORING HOW MUCH STRATUS MIXES/CLEARS OUT
OVER SOUTH CENTRAL MINNESOTA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
245 PM CST SAT FEB 4 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1146 AM CST SAT FEB 4 2012
.SHORT TERM...TODAY THROUGH TUESDAY
248 AM CST SAT FEB 4 2012
THE MAIN FOCUS IN THE SHORT TERM IS WITH CLOUD TRENDS THROUGH THE
WEEKEND FOLLOWED BY A WARM UP ON MONDAY AND A COLD FRONT MONDAY
NIGHT.
CURRENTLY...A CLOSED MID LEVEL LOW CONTINUES TO CHURN EASTWARD
ACROSS SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS WITH A SURFACE
LOW CENTERED OVER SOUTHERN MISSOURI. THE PRECIPITATION FROM THIS
SYSTEM IS CONFINED TO THE SOUTHERN HALF OF IOWA AND WILL CONTINUE
TO DRIFT SOUTH TODAY AND NOT AFFECT THE FORECAST AREA. THIS IS
MAINLY DUE TO A RIDGE OF HIGH PRESSURE THAT EXTENDS FROM NORTH
DAKOTA EAST THROUGH THE GREAT LAKES. LOW LEVEL STRATUS AND FOG
REMAINS IN PLACE ACROSS THE DAKOTAS INTO MUCH OF MINNESOTA DUE TO
MOISTURE STUCK UNDER 950MB INVERSION. OTHERWISE SKIES HAVE MAINLY
BEEN CLEAR ACROSS WISCONSIN WITH SOME HIGH LEVEL CLOUDS COMING IN
THROUGH THE SOUTHERN PART OF THE STATE.
WHAT HAPPENS WITH THE CLOUDS TODAY IS THE MAIN QUESTION AS MUCH OF
THE 04.00Z GUIDANCE IS SUGGESTING A GRADUAL CLEARING FROM NORTH TO
SOUTH. AS THE SYSTEM TO THE SOUTH STARTS TO DIVE SOUTH TODAY...THE
SURFACE RIDGE AXIS WILL DROP SOUTH AS WELL AND SHOULD BRING DRIER
AIR DOWN WITH IT. THE PROBLEM IS THAT THE 950-900MB INVERSION IS
FORECAST TO HANG ON INTO THE AFTERNOON. ALSO...THE CURRENT
STRATUS EXTENDS UP INTO THE CORE OF THE RIDGE WITH THE EASTERN
EDGE CURRENTLY PUSHING EAST TOWARD THE TWIN CITIES AND SOUTHEAST
MINNESOTA. THE 04.07Z RUC 950MB RH FIELD SEEMS TO HAVE A GOOD
GRASP ON THE CURRENT STRATUS AND MAKES A PUSH TO THE EAST THROUGH
16Z THIS MORNING WITH THE 90-100 PERCENT CONTOURS. THUS...HAVE
KEPT SKIES MAINLY CLOUDY THROUGH THE MORNING ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. THIS WILL
HAVE A BIG IMPACT ON TEMPERATURES WITH MID 30S LIKELY FOR HIGHS
WHERE THE CLOUDS HANG ON AND 40S LIKELY ACROSS CENTRAL WISCONSIN
WHERE IT IS SUNNY TODAY. BY TONIGHT...CLOUDS SHOULD HAVE CLEARED
THE REGION BUT CONFIDENCE IS NOT VERY HIGH CONSIDERING RECENT
TRENDS.
THE FOCUS THEN SHIFTS TO A COLD FRONT THAT WILL DROP THROUGH THE
REGION ON MONDAY NIGHT. WITH DECENT LOW LEVEL WARM ADVECTION AHEAD
OF THIS FRONT ON MONDAY...SURFACE TEMPERATURES SHOULD WARM NICELY
INTO THE MID 40S THROUGH MUCH OF THE REGION. CLOUD COVER WILL BE
ON THE INCREASE AS THE FRONT APPROACHES FROM THE NORTH MONDAY
NIGHT...BUT DEEP MOISTURE AND FORCING IS LACKING WITH THIS FEATURE
AND THUS SHOULD NOT PRODUCE ANY PRECIPITATION.
.LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT
248 AM CST SAT FEB 4 2012
THE QUIET WEATHER PATTERN CONTINUES THROUGH THE REST OF THE WEEK
WITH THE MAIN STORY BEING WITH A BRIEF COLD SURGE TOWARD THE LATER
PART OF THE WEEK.
AFTER THE COLD FRONT DROPS THROUGH ON MONDAY NIGHT A BROAD RIDGE
OF HIGH PRESSURE WILL DROP DOWN INTO THE UPPER MISSISSIPPI RIVER
VALLEY REGION TUESDAY NIGHT INTO WEDNESDAY. BEYOND THIS...THERE
ARE SOME DIFFERENCES THAT POP UP BETWEEN THE 04.00Z GFS...GEM AND
ECMWF IN REGARDS TO THE TIMING OF A COLD FRONT COMING THROUGH
LATER IN THE WEEK. THE GFS AND GEM ARE MUCH MORE PROGRESSIVE AND HAS
IT THROUGH THE REGION BY THURSDAY MORNING WHILE THE ECMWF BRINGS
IT THROUGH ON FRIDAY MORNING. THE GFS AND GEM SOLUTIONS WOULD
BRING THE COLD SURGE OF -15C TO -20C 850MB TEMPERATURES DOWN IN
THE REGION FASTER THAN WHAT THE ECMWF SUGGESTS AS THE POLAR
VORTEX DROPS SOUTHEAST ACROSS CANADA. FOR NOW...HAVE DONE A BLEND
WITH THE TIMING BETWEEN THE 04.00Z GFS/ECMWF AND WENT WITH THE
COLDER TEMPERATURES ON FRIDAY WHEN THE COLD POOL WILL MORE LIKELY
BE IN PLACE. ITS PLAUSIBLE AT THIS POINT THAT THE TEMPERATURES ARE
TOO WARM FOR THURSDAY INTO FRIDAY...BUT CONFIDENCE IS NOT HIGH
ENOUGH AT THIS POINT WITH THE CORE OF THE COLD AIR EXPECTED TO BE
OFF TO THE EAST TOWARD THE EASTERN GREAT LAKES.
&&
.AVIATION...THROUGH 18Z SUNDAY
1146 AM CST SAT FEB 4 2012
A VERY DIFFICULT AVIATION FORECAST...EVEN FOR THE NEXT 6 TO 12
HOURS...DUE MOSTLY TO THE PRESENCE OF A VLIFR/LIFR STRATUS DECK
OVER SOUTH CENTRAL MINNESOTA AND THE EASTERN DAKOTAS. UNDERNEATH
THE STRATUS DECK...VISIBILITIES RANGE FROM LIFR TO IFR WITH SLOW
IMPROVEMENT OCCURRING THROUGH THE MORNING. SUNSHINE APPEARS TO
HAVE STALLED THE EASTWARD MOVEMENT OF THE STRATUS TO THE DODGE
CENTER MN AREA. QUESTION WITH THE STRATUS DECK OVER SOUTH CENTRAL
MINNESOTA IS HOW MUCH MIXES/CLEARS OUT DURING THE AFTERNOON.
SCENARIO 1...IF IT MOST OF IT CLEARS OUT...THEN WE WAIT FOR A
10-15 KT NORTHWEST WIND SITTING ABOVE THE SURFACE TO BRING THE
STRATUS OVER THE EASTERN DAKOTAS INTO THE TAF SITES. SCENARIO
2...IF SOME OF THE STRATUS STILL EXISTS BY THE TIME THE SUN STARTS
TO SET...THE NORTHWEST WIND WOULD BRING IT INTO THE TAF SITES
QUICKER. TRIED TO PLAY A SEMI-COMPROMISE APPROACH...BRINGING THE
STRATUS INTO KRST AROUND 03Z AND KLSE AT 04Z. DID THROW IN A VCFG
AND SCT002 AT KRST FROM 21-03Z IN CASE IT COMES IN FASTER.
ANTICIPATING CEILINGS TO DROP TO LIFR-IFR. VISIBILITIES ARE LIKELY
TO COME DOWN TOO...BUT THE WIND MAY ONLY ALLOW THEM TO DROP TO
IFR-MVFR. AFTER A FEW HOURS...INDICATIONS ARE THAT THE WIND SHOULD
HELP TO BRING CEILINGS UP A FEW HUNDRED FEET. LATE SUNDAY
MORNING...HEATING MAY ALLOW THE STRATUS AND BR TO DISSIPATE...BUT
CONFIDENCE IS LOW BEING AT THE END OF THE TAF PERIOD AND MODEL
HANDLING OF THE STRATUS LATELY. THEREFORE...HAVE NOT SHOWN THIS
CLEARING YET.
NEEDLESS TO SAY...THE AVIATION FORECAST IS LOW CONFIDENCE. BIG
THING RIGHT NOW IS MONITORING HOW MUCH STRATUS MIXES/CLEARS OUT
OVER SOUTH CENTRAL MINNESOTA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
248 AM CST SAT FEB 4 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION...AJ
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
538 AM CST SAT FEB 4 2012
.SHORT TERM...TODAY THROUGH TUESDAY
248 AM CST SAT FEB 4 2012
THE MAIN FOCUS IN THE SHORT TERM IS WITH CLOUD TRENDS THROUGH THE
WEEKEND FOLLOWED BY A WARM UP ON MONDAY AND A COLD FRONT MONDAY
NIGHT.
CURRENTLY...A CLOSED MID LEVEL LOW CONTINUES TO CHURN EASTWARD
ACROSS SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS WITH A SURFACE
LOW CENTERED OVER SOUTHERN MISSOURI. THE PRECIPITATION FROM THIS
SYSTEM IS CONFINED TO THE SOUTHERN HALF OF IOWA AND WILL CONTINUE
TO DRIFT SOUTH TODAY AND NOT AFFECT THE FORECAST AREA. THIS IS
MAINLY DUE TO A RIDGE OF HIGH PRESSURE THAT EXTENDS FROM NORTH
DAKOTA EAST THROUGH THE GREAT LAKES. LOW LEVEL STRATUS AND FOG
REMAINS IN PLACE ACROSS THE DAKOTAS INTO MUCH OF MINNESOTA DUE TO
MOISTURE STUCK UNDER 950MB INVERSION. OTHERWISE SKIES HAVE MAINLY
BEEN CLEAR ACROSS WISCONSIN WITH SOME HIGH LEVEL CLOUDS COMING IN
THROUGH THE SOUTHERN PART OF THE STATE.
WHAT HAPPENS WITH THE CLOUDS TODAY IS THE MAIN QUESTION AS MUCH OF
THE 04.00Z GUIDANCE IS SUGGESTING A GRADUAL CLEARING FROM NORTH TO
SOUTH. AS THE SYSTEM TO THE SOUTH STARTS TO DIVE SOUTH TODAY...THE
SURFACE RIDGE AXIS WILL DROP SOUTH AS WELL AND SHOULD BRING DRIER
AIR DOWN WITH IT. THE PROBLEM IS THAT THE 950-900MB INVERSION IS
FORECAST TO HANG ON INTO THE AFTERNOON. ALSO...THE CURRENT
STRATUS EXTENDS UP INTO THE CORE OF THE RIDGE WITH THE EASTERN
EDGE CURRENTLY PUSHING EAST TOWARD THE TWIN CITIES AND SOUTHEAST
MINNESOTA. THE 04.07Z RUC 950MB RH FIELD SEEMS TO HAVE A GOOD
GRASP ON THE CURRENT STRATUS AND MAKES A PUSH TO THE EAST THROUGH
16Z THIS MORNING WITH THE 90-100 PERCENT CONTOURS. THUS...HAVE
KEPT SKIES MAINLY CLOUDY THROUGH THE MORNING ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. THIS WILL
HAVE A BIG IMPACT ON TEMPERATURES WITH MID 30S LIKELY FOR HIGHS
WHERE THE CLOUDS HANG ON AND 40S LIKELY ACROSS CENTRAL WISCONSIN
WHERE IT IS SUNNY TODAY. BY TONIGHT...CLOUDS SHOULD HAVE CLEARED
THE REGION BUT CONFIDENCE IS NOT VERY HIGH CONSIDERING RECENT
TRENDS.
THE FOCUS THEN SHIFTS TO A COLD FRONT THAT WILL DROP THROUGH THE
REGION ON MONDAY NIGHT. WITH DECENT LOW LEVEL WARM ADVECTION AHEAD
OF THIS FRONT ON MONDAY...SURFACE TEMPERATURES SHOULD WARM NICELY
INTO THE MID 40S THROUGH MUCH OF THE REGION. CLOUD COVER WILL BE
ON THE INCREASE AS THE FRONT APPROACHES FROM THE NORTH MONDAY
NIGHT...BUT DEEP MOISTURE AND FORCING IS LACKING WITH THIS FEATURE
AND THUS SHOULD NOT PRODUCE ANY PRECIPITATION.
.LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT
248 AM CST SAT FEB 4 2012
THE QUIET WEATHER PATTERN CONTINUES THROUGH THE REST OF THE WEEK
WITH THE MAIN STORY BEING WITH A BRIEF COLD SURGE TOWARD THE LATER
PART OF THE WEEK.
AFTER THE COLD FRONT DROPS THROUGH ON MONDAY NIGHT A BROAD RIDGE
OF HIGH PRESSURE WILL DROP DOWN INTO THE UPPER MISSISSIPPI RIVER
VALLEY REGION TUESDAY NIGHT INTO WEDNESDAY. BEYOND THIS...THERE
ARE SOME DIFFERENCES THAT POP UP BETWEEN THE 04.00Z GFS...GEM AND
ECMWF IN REGARDS TO THE TIMING OF A COLD FRONT COMING THROUGH
LATER IN THE WEEK. THE GFS AND GEM ARE MUCH MORE PROGRESSIVE AND HAS
IT THROUGH THE REGION BY THURSDAY MORNING WHILE THE ECMWF BRINGS
IT THROUGH ON FRIDAY MORNING. THE GFS AND GEM SOLUTIONS WOULD
BRING THE COLD SURGE OF -15C TO -20C 850MB TEMPERATURES DOWN IN
THE REGION FASTER THAN WHAT THE ECMWF SUGGESTS AS THE POLAR
VORTEX DROPS SOUTHEAST ACROSS CANADA. FOR NOW...HAVE DONE A BLEND
WITH THE TIMING BETWEEN THE 04.00Z GFS/ECMWF AND WENT WITH THE
COLDER TEMPERATURES ON FRIDAY WHEN THE COLD POOL WILL MORE LIKELY
BE IN PLACE. ITS PLAUSIBLE AT THIS POINT THAT THE TEMPERATURES ARE
TOO WARM FOR THURSDAY INTO FRIDAY...BUT CONFIDENCE IS NOT HIGH
ENOUGH AT THIS POINT WITH THE CORE OF THE COLD AIR EXPECTED TO BE
OFF TO THE EAST TOWARD THE EASTERN GREAT LAKES.
&&
.AVIATION...TODAY AND TONIGHT
538 AM CST SAT FEB 4 2012
AREAS OF BR CAN BE EXPECTED AT THE TAF SITES THIS
MORNING...PRODUCING MVFR/IFR CONDITIONS. PLAN ON VISIBILITIES IN THE
2 TO 4 SM RANGE. THE BR WILL GRADUALLY DISSIPATE LATE THIS MORNING
AS DRIER AIR MOVES IN. HIGH PRESSURE WILL BUILD INTO THE UPPER
MISSISSIPPI RIVER VALLEY THIS AFTERNOON INTO TONIGHT PROVIDING VFR
CONDITIONS. SCT/BKN MID TO HIGH LEVEL CLOUDS MAY SPILL INTO THE
AREA FROM THE SOUTH AS A LOW PRESSURE SYSTEM MOVES ACROSS THE MID
MISSISSIPPI RIVER VALLEY. GUIDANCE IS SUGGESTING SOME PATCHY FOG
MAY DEVELOP TONIGHT...BUT CONFIDENCE IS LOW ON THIS OCCURRING
GIVEN THE DRIER AIR AND SUBSIDENCE MOVING IN WITH THE HIGH. WILL
HAVE TO MONITOR THIS POTENTIAL CLOSELY.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
248 AM CST SAT FEB 4 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
248 AM CST SAT FEB 4 2012
.SHORT TERM...TODAY THROUGH TUESDAY
248 AM CST SAT FEB 4 2012
THE MAIN FOCUS IN THE SHORT TERM IS WITH CLOUD TRENDS THROUGH THE
WEEKEND FOLLOWED BY A WARM UP ON MONDAY AND A COLD FRONT MONDAY
NIGHT.
CURRENTLY...A CLOSED MID LEVEL LOW CONTINUES TO CHURN EASTWARD
ACROSS SOUTH CENTRAL NEBRASKA/NORTH CENTRAL KANSAS WITH A SURFACE
LOW CENTERED OVER SOUTHERN MISSOURI. THE PRECIPITATION FROM THIS
SYSTEM IS CONFINED TO THE SOUTHERN HALF OF IOWA AND WILL CONTINUE
TO DRIFT SOUTH TODAY AND NOT AFFECT THE FORECAST AREA. THIS IS
MAINLY DUE TO A RIDGE OF HIGH PRESSURE THAT EXTENDS FROM NORTH
DAKOTA EAST THROUGH THE GREAT LAKES. LOW LEVEL STRATUS AND FOG
REMAINS IN PLACE ACROSS THE DAKOTAS INTO MUCH OF MINNESOTA DUE TO
MOISTURE STUCK UNDER 950MB INVERSION. OTHERWISE SKIES HAVE MAINLY
BEEN CLEAR ACROSS WISCONSIN WITH SOME HIGH LEVEL CLOUDS COMING IN
THROUGH THE SOUTHERN PART OF THE STATE.
WHAT HAPPENS WITH THE CLOUDS TODAY IS THE MAIN QUESTION AS MUCH OF
THE 04.00Z GUIDANCE IS SUGGESTING A GRADUAL CLEARING FROM NORTH TO
SOUTH. AS THE SYSTEM TO THE SOUTH STARTS TO DIVE SOUTH TODAY...THE
SURFACE RIDGE AXIS WILL DROP SOUTH AS WELL AND SHOULD BRING DRIER
AIR DOWN WITH IT. THE PROBLEM IS THAT THE 950-900MB INVERSION IS
FORECAST TO HANG ON INTO THE AFTERNOON. ALSO...THE CURRENT
STRATUS EXTENDS UP INTO THE CORE OF THE RIDGE WITH THE EASTERN
EDGE CURRENTLY PUSHING EAST TOWARD THE TWIN CITIES AND SOUTHEAST
MINNESOTA. THE 04.07Z RUC 950MB RH FIELD SEEMS TO HAVE A GOOD
GRASP ON THE CURRENT STRATUS AND MAKES A PUSH TO THE EAST THROUGH
16Z THIS MORNING WITH THE 90-100 PERCENT CONTOURS. THUS...HAVE
KEPT SKIES MAINLY CLOUDY THROUGH THE MORNING ACROSS SOUTHEAST
MINNESOTA...NORTHEAST IOWA AND FAR SOUTHWEST WISCONSIN. THIS WILL
HAVE A BIG IMPACT ON TEMPERATURES WITH MID 30S LIKELY FOR HIGHS
WHERE THE CLOUDS HANG ON AND 40S LIKELY ACROSS CENTRAL WISCONSIN
WHERE IT IS SUNNY TODAY. BY TONIGHT...CLOUDS SHOULD HAVE CLEARED
THE REGION BUT CONFIDENCE IS NOT VERY HIGH CONSIDERING RECENT
TRENDS.
THE FOCUS THEN SHIFTS TO A COLD FRONT THAT WILL DROP THROUGH THE
REGION ON MONDAY NIGHT. WITH DECENT LOW LEVEL WARM ADVECTION AHEAD
OF THIS FRONT ON MONDAY...SURFACE TEMPERATURES SHOULD WARM NICELY
INTO THE MID 40S THROUGH MUCH OF THE REGION. CLOUD COVER WILL BE
ON THE INCREASE AS THE FRONT APPROACHES FROM THE NORTH MONDAY
NIGHT...BUT DEEP MOISTURE AND FORCING IS LACKING WITH THIS FEATURE
AND THUS SHOULD NOT PRODUCE ANY PRECIPITATION.
.LONG TERM...TUESDAY NIGHT THROUGH FRIDAY NIGHT
248 AM CST SAT FEB 4 2012
THE QUIET WEATHER PATTERN CONTINUES THROUGH THE REST OF THE WEEK
WITH THE MAIN STORY BEING WITH A BRIEF COLD SURGE TOWARD THE LATER
PART OF THE WEEK.
AFTER THE COLD FRONT DROPS THROUGH ON MONDAY NIGHT A BROAD RIDGE
OF HIGH PRESSURE WILL DROP DOWN INTO THE UPPER MISSISSIPPI RIVER
VALLEY REGION TUESDAY NIGHT INTO WEDNESDAY. BEYOND THIS...THERE
ARE SOME DIFFERENCES THAT POP UP BETWEEN THE 04.00Z GFS...GEM AND
ECMWF IN REGARDS TO THE TIMING OF A COLD FRONT COMING THROUGH
LATER IN THE WEEK. THE GFS AND GEM ARE MUCH MORE PROGRESSIVE AND HAS
IT THROUGH THE REGION BY THURSDAY MORNING WHILE THE ECMWF BRINGS
IT THROUGH ON FRIDAY MORNING. THE GFS AND GEM SOLUTIONS WOULD
BRING THE COLD SURGE OF -15C TO -20C 850MB TEMPERATURES DOWN IN
THE REGION FASTER THAN WHAT THE ECMWF SUGGESTS AS THE POLAR
VORTEX DROPS SOUTHEAST ACROSS CANADA. FOR NOW...HAVE DONE A BLEND
WITH THE TIMING BETWEEN THE 04.00Z GFS/ECMWF AND WENT WITH THE
COLDER TEMPERATURES ON FRIDAY WHEN THE COLD POOL WILL MORE LIKELY
BE IN PLACE. ITS PLAUSIBLE AT THIS POINT THAT THE TEMPERATURES ARE
TOO WARM FOR THURSDAY INTO FRIDAY...BUT CONFIDENCE IS NOT HIGH
ENOUGH AT THIS POINT WITH THE CORE OF THE COLD AIR EXPECTED TO BE
OFF TO THE EAST TOWARD THE EASTERN GREAT LAKES.
&&
.AVIATION...THROUGH 06Z SUNDAY
1135 PM CST FRI FEB 3 2012
STRATUS HAS SCATTERED OUT OF BOTH TAF SITES AND AT 05Z THE BACK
EDGE IS JUST SOUTH OF BOTH KLSE AND KRST AND HAS SLOWED ITS
SOUTHWARD PROGRESSION. ANOTHER BATCH OF LOW STRATUS AND LOW
VISIBILITIES WAS LOCATED OVER CENTRAL MINNESOTA. THIS CENTRAL
MINNESOTA AREA IS SHOWING SOME SOUTHEASTWARD PROGRESSION. MAIN
CHALLENGE CONTINUES TO BE ON THESE CLOUDS THROUGH THE NEXT 6 TO 10
HOURS OR SO. 04.04Z RUC 975MB RELATIVE HUMIDITY PROG INDICATES
THESE CLOUDS MAY BUILD BACK INTO BOTH TAF SITES BETWEEN 12Z-
15Z...WITH A STRONGER SIGNAL OVER SOUTHEAST MINNESOTA. THUS DID
BRING SOME LOWER VISIBILITIES INTO KRST WITH SCATTERED STRATUS AT
200 FEET. THIS WILL HAVE TO BE WATCHED CLOSELY OVERNIGHT AS
CONFIDENCE NOT HIGH. ANY STRATUS THAT DOES WORK ITS WAY BACK IN
SHOULD LIFT LATER SATURDAY AS FLOW BECOMES MORE NORTHERLY AS AN
AREA OF LOW PRESSURE MOVES SOUTH OF THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
248 AM CST SAT FEB 4 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 PM CST FRI FEB 3 2012
.SHORT TERM...TONIGHT THROUGH SUNDAY NIGHT
336 PM CST FRI FEB 3 2012
AT 3 PM...WATCHING THE LOW CLOUDS ERODE ACROSS CENTRAL WISCONSIN.
THINKING THAT THESE LOW CLOUDS WILL CONTINUE TO ERODE ALONG AND
NORTH OF THE INTERSTATE 90 CORRIDOR IN WISCONSIN THIS EVENING.
EVEN THROUGH THESE CLOUDS ARE DISSIPATING...DEBRIS CLOUDS FROM THE
SYSTEM TO THE SOUTHWEST WILL CONTINUE TO MOVE INTO THE AREA. THESE
CLOUDS WILL HELP KEEP TEMPERATURES GENERALLY AROUND 30 ACROSS
SOUTH AND EAST OF THE INTERSTATE 94 CORRIDOR...AND IN THE LOWER
AND MID TEENS FOR THE REMAINDER OF THE AREA.
WITH LIGHT WINDS AND SOME SNOW MELT ACROSS NORTH CENTRAL
WISCONSIN...THERE MAY BE SOME FOG DEVELOPMENT OVERNIGHT. THE MAIN
QUESTION IS HOW DENSE THIS FOG MAY GET. THIS WILL GREATLY DEPEND
UPON THE AMOUNT OF DRY AIR THAT ADVECTS INTO THIS AREA LATE
TONIGHT.
ON SATURDAY NIGHT...THE LOW PRESSURE SYSTEM WILL SHEAR APART TO
OUR SOUTHWEST. AS THIS OCCURS...SKIES WILL CLEAR ACROSS THE
SOUTHERN AND WESTERN PARTS OF THE FORECAST AREA.
.LONG TERM...MONDAY THROUGH FRIDAY
336 PM CST FRI FEB 3 2012
ON MONDAY...925 MB TEMPERATURES WARM INTO THE 2 TO 4C RANGE AHEAD
OF APPROACHING CANADIAN COLD FRONT. WITH MUCH OF THE AREA LESS
THAN 2 INCHES AND SUNNY SKIES...TEMPERATURES WILL CLIMB INTO THE
MID AND UPPER 40S ACROSS THE FORECAST AREA. THIS IS IN VERY GOOD
AGREEMENT WITH THE 03.12Z ECMWF. BEHIND THIS COLD FRONT...
THE HIGH TEMPERATURES WILL END UP BEING CLOSER TO NORMAL /MID TO
UPPER 20S/ FOR BOTH TUESDAY AND WEDNESDAY. MEANWHILE LOW
TEMPERATURES WILL BE IN THE TEENS AND LOWER 20S WHICH IS STILL
ABOUT 10 DEGREES ABOVE NORMAL.
FOR WEDNESDAY AND WEDNESDAY NIGHT...THE 03.12Z ECMWF HAS BACKED
AWAY FROM ITS PRECIPITATION. SINCE THIS MODEL WAS THE ONLY ONE
WHICH WAS SHOWING IT...DECIDED TO DROP THE PRECIPITATION FOR THIS
TIME PERIOD.
BEYOND THIS TIME PERIOD...THE MODELS CONTINUE TO STRUGGLE WITH THE
DEVELOPMENT OF A DEEP LONG WAVE TROUGH ACROSS EASTERN NORTH
AMERICA. THE MAIN QUESTION CONTINUES TO BE HOW FAR WEST WILL THIS
TROUGH EXTEND. LOOKING AT THE GFS ENSEMBLE...MANY OF ITS FAMILY
MEMBERS KEEP THE COLDEST AIR TO OUR NORTHEAST. HOWEVER THE 03.12Z
ECMWF HAS ITS COLDEST AIR CENTERED OVER THE AREA ON FRIDAY
AFTERNOON. THIS WAS THE FIRST TIME THAT THIS MODEL HAS SHOWN
THIS. WITH THE GFS ENSEMBLE SHOWING AN ARCTIC OSCILLATION RANGING
FROM 0 TO -4 AND THE NORTH ATLANTIC OSCILLATION MAINLY POSITIVE...
NOT SURE HOW MUCH OF THE COLD AIR WILL ACTUALLY MOVE INTO THE
REGION...THEREFORE...STAYED WITH THE ALL BLEND MAXIMUM/MINIMUM
TEMPERATURES. EVEN IF THE ARCTIC AIR DID MOVE INTO THE
REGION...THE CFS VERSION 2 CONTINUES TO SUGGEST THAT IT WOULD BE
VERY BRIEF.
&&
.AVIATION...THROUGH 06Z SUNDAY
1135 PM CST FRI FEB 3 2012
STRATUS HAS SCATTERED OUT OF BOTH TAF SITES AND AT 05Z THE BACK
EDGE IS JUST SOUTH OF BOTH KLSE AND KRST AND HAS SLOWED ITS
SOUTHWARD PROGRESSION. ANOTHER BATCH OF LOW STRATUS AND LOW
VISIBILITIES WAS LOCATED OVER CENTRAL MINNESOTA. THIS CENTRAL
MINNESOTA AREA IS SHOWING SOME SOUTHEASTWARD PROGRESSION. MAIN
CHALLENGE CONTINUES TO BE ON THESE CLOUDS THROUGH THE NEXT 6 TO 10
HOURS OR SO. 04.04Z RUC 975MB RELATIVE HUMIDITY PROG INDICATES
THESE CLOUDS MAY BUILD BACK INTO BOTH TAF SITES BETWEEN 12Z-
15Z...WITH A STRONGER SIGNAL OVER SOUTHEAST MINNESOTA. THUS DID
BRING SOME LOWER VISIBILITIES INTO KRST WITH SCATTERED STRATUS AT
200 FEET. THIS WILL HAVE TO BE WATCHED CLOSELY OVERNIGHT AS
CONFIDENCE NOT HIGH. ANY STRATUS THAT DOES WORK ITS WAY BACK IN
SHOULD LIFT LATER SATURDAY AS FLOW BECOMES MORE NORTHERLY AS AN
AREA OF LOW PRESSURE MOVES SOUTH OF THE AREA.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
242 PM CST FRI FEB 3 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LINCOLN IL
236 AM CST MON FEB 6 2012
.DISCUSSION...
ISSUED 235 AM CST MON FEB 6 2012
SHORT TERM...TODAY THROUGH WEDNESDAY...
MAIN HEADACHES THE LAST FEW HOURS HAVE BEEN WITH LOW CLOUDS AND
DENSE FREEZING FOG DEVELOPMENT. STRATUS DECK HAS BEEN ADVANCING
SOUTHEASTWARD AND HAD REACHED THE I-55 CORRIDOR AT 2 AM.
VISIBILITIES ALONG THIS EDGE QUICKLY TANKED AND THE 1/4 MILE
VISIBILITY EXTENDS NORTHWEST FOR ABOUT 60 MILES FROM THE LEADING
EDGE. HAVE ALSO BEEN SEEING SOME PATCHIER DENSE FOG DEVELOPING
OVER THE EASTERN CWA...IN AREAS WHERE SKIES HAVE BEEN MAINLY
CLEAR. MODEL GUIDANCE WITH THIS STRATUS DECK OVER THE LAST DAY OR
TWO HAS BEEN QUITE POOR. THE HRRR APPEARS TO DO THE BEST JOB...BUT
ONLY GOES OUT ABOUT 12 HOURS. THE LATEST RAPID-REFRESH ALSO SEEMS
TO BE OK...AND SPREADS THE CLOUDS OVER MOST OF THE REMAINING CWA
EARLY THIS MORNING AND KEEPS LOWER VISIBILITIES GOING THROUGH
ABOUT 9-10 AM...WITH FOG LIFTING FROM THE NORTHWEST. WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FOR AREAS BETWEEN THE ILLINOIS
RIVER AND I-70 FOR THIS MORNING. TEMPERATURES TODAY WILL BE VERY
TRICKY DEPENDING ON HOW FAST THE CLOUDS FINALLY BREAK UP THIS
AFTERNOON...IF THEY INDEED DO SO. HAVE UNDERCUT GUIDANCE
TEMPERATURES UNDERNEATH BY A FEW DEGREES UNDERNEATH THE STRATUS
DECK...BUT ANY BREAKUP TOO EARLY IN THE DAY WILL CAUSE SIGNIFICANT
ERRORS IN THE HIGH TEMPERATURE FORECAST.
THE OTHER FOCUS DURING THIS PERIOD WILL BE AS A SHORTWAVE...THE
REMNANTS OF A CUTOFF LOW CURRENTLY OVER THE CENTRAL ROCKIES...
INTERACTS WITH ANOTHER WAVE WHICH WILL SWEEP ACROSS THE GREAT
LAKES ON TUESDAY AND WEDNESDAY. STILL NOT A LOT OF MOISTURE
AVAILABILITY WITH THIS SYSTEM...WITH MOST OF THE MODEL GUIDANCE
SUPPORTING LOW CHANCE POPS ACROSS THE SOUTHERN HALF OF THE CWA.
MAY SEE SOME MINOR SNOW ACCUMULATIONS TUESDAY EVENING NEAR THE
I-72 CORRIDOR...DEPENDING ON HOW FAST SURFACE TEMPERATURES DROP
BEFORE THE PRECIPITATION EXITS.
LONG TERM...THURSDAY THROUGH SUNDAY...
MAIN FOCUS IN THIS PERIOD REMAINS WITH ARCTIC AIR MASS WHICH WILL
DROP INTO THE GREAT LAKES LATE IN THE WEEK. COLD FRONT PROGGED TO
MOVE ACROSS THE AREA EARLY FRIDAY MORNING...ALTHOUGH MOST OF THE
MOISTURE WILL BE CLOSER TO THE GREAT LAKES AND WILL GO WITH A DRY
FRONTAL PASSAGE HERE. HOWEVER...LATEST GFS/ECMWF BOTH BRING 850
MB TEMPERATURES AS LOW AS -17C INTO THE CWA BY SATURDAY MORNING...
WHICH WOULD KEEP MUCH OF THE CWA AT OR BELOW FREEZING ON
SATURDAY. AS WITH MOST OF THE COLD PERIODS THIS WINTER...ONLY
LOOKING AT ABOUT A 36-48 HOUR PERIOD WHERE IT WOULD ACTUALLY BE
CONSIDERED TO BE COLD...BEFORE TEMPERATURES QUICKLY RETURN TO NEAR
NORMAL.
GEELHART
&&
.AVIATION...
ISSUED 1150 PM CST SUN FEB 5 2012
GOING TO BE PESSIMISTIC THROUGH THE PERIOD WITH THE TAFS. LARGE
AREA OF VLIFR CONDITIONS HAS BEEN APPROACHING THE AREA ALL NIGHT
AND HAS FINALLY REACHED PIA. BASED ON SHORT RANGE HIGH RES
MODELS...BELIEVE THIS TREND WILL CONTINUE INTO SPI/BMI/DEC DURING
THE OVERNIGHT HOURS. THINK IT WILL ALSO REACH CMI BUT TOWARD
MORNING. IN ADDITION...LIGHT FOG HAS BEEN DEVELOPING AT THE SITES
WITH NO CLOUDS. ONCE CLOUD COVER REACHES THESE SITES...VIS WILL
PROBABLY DECREASE AGAIN. THE OVERALL BIG QUESTION IS WILL THERE BE
ANY IMPROVEMENT DURING THE DAY TOMORROW. SHORT TERM HIGH RES
MODELS DO NOT EXTENDED QUITE FAR ENOUGH...BUT BASED ON PERSISTANCE
FROM TODAY ACROSS IOWA AND SEEING THERE IS NOT FRONT AND DRIER
AIR FORECAST TO MOVE INTO THE AREA TOMORROW...BELIEVE ONLY
IMPROVEMENT WILL BE WITH VISIBILITIES AS THE WINDS INCREASE FROM
THE WEST-SOUTHWEST DURING THE MORNING. WILL KEEP CIGS BELOW 1KFT
THROUGH THE ENTIRE FORECAST PERIOD. WINDS WILL DECREASE AROUND
SUNSET AT ALL SITES SO BELIEVE VIS WILL FALL AGAIN TO AROUND 3SM.
COULD GO LOWER BUT VERY UNSURE AT THIS TIME. WINDS WILL BE LIGHT
TONIGHT BUT INCREASE IN SPEED OUT OF THE WEST-SOUTHWEST
TOMORROW...THEN DECREASE AGAIN TOMORROW EVENING.
AUTEN
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY FOR ILZ031-037-038-041>057-061 UNTIL NOON CST.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
359 AM EST MON FEB 6 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL KEEP DRY MILD WEATHER ACROSS CENTRAL INDIANA
THROUGH TUESDAY. A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL
BRING THE CHANCE FOR LIGHT PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER FOR LATE
WEEK AND INTO THE WEEKEND. THE EXPANSION OF A BROAD UPPER LEVEL
TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
CLEAR SKIES OVER A MAJORITY OF THE FORECAST AREA THIS MORNING. ONLY
EXCEPTION IS OVER NORTHERN WABASH VALLEY WHERE SHALLOW FREEZING FOG
AND POCKETS OF LOW STRATUS HAVE FORMED EARLY THIS MORNING. TEMPS AT
08Z WERE BELOW FREEZING...FROM THE MID 20S TO LOWER 30S.
MAIN FORECAST ISSUE FOCUSES ON FREEZING FOG THROUGH MID MORNING AND
POTENTIAL IMPACTS FROM DEVELOPING POCKETS OF STRATUS. BROAD AREA OF
STRATUS WITH CEILINGS AT OR BELOW 500FT CONTINUES TO EXPAND SLOWLY
EAST ACROSS NORTHERN ILLINOIS. MOST OF THE SHORT RANGE MODEL
GUIDANCE IS STRUGGLING MIGHTILY WITH THE LOCATION AND EXPANSION OF
THE LARGER STRATUS DECK OVER ILLINOIS...WITH ONLY THE RUC AND TO A
LESSER EXTENT THE 06Z NAM HINTING AT ITS PRESENCE CURRENTLY. HAVE
INTRODUCED AN SPS FOR FREEZING FOG OVER THE ENTIRE FORECAST AREA
THROUGH MID MORNING WITH THE MAIN CONCERN OVER NORTHWEST COUNTIES
AND THE NORTHERN WABASH VALLEY WHERE MANY LOCATIONS ALREADY
REPORTING BELOW 1SM. AT THIS POINT APPEARS DENSE FOG IN NORTHWEST
COUNTIES REMAINS PATCHY BUT SHOULD IT BECOME MORE WIDESPREAD...MAY
NEED TO CONSIDER A FREEZING FOG ADVISORY. WILL CONTINUE TO MONITOR
TRENDS CLOSELY OVER THE NEXT FEW HOURS. SPS SHOULD REMAIN SUFFICIENT
OVER THE REST OF THE FORECAST AREA AS FOG LIKELY TO REMAIN PATCHY.
ONCE VISIBILITIES IMPROVE LATER THIS MORNING...REMAINDER OF THE DAY
SHOULD BE FAIRLY QUIET WITH HIGH PRESSURE ACROSS THE REGION. ONE BIG
CAVEAT WILL BE THE LOCATION AND EXTENT OF THE STRATUS DECK AND JUST
HOW QUICKLY THAT MIXES OUT. AT THIS POINT...APPEARS THE DECK WILL
SPREAD ACROSS FAR NORTHWEST PORTIONS OF THE FORECAST AREA LATER THIS
MORNING. HOWEVER...UNCERTAINTY IS VERY HIGH WITH RESPECT TO HOW MUCH
FURTHER SOUTHEAST THE DECK MAY EXPAND INTO THE FORECAST AREA. HAVE
CHOSEN TO CARRY MOSTLY CLOUDY SKIES OVER NORTHWEST COUNTIES WITH
MOSTLY SUNNY/PARTLY CLOUDY CONDITIONS ELSEWHERE. ADJUSTMENTS WILL BE
MADE ACCORDINGLY THROUGH THE MORNING AS NEEDED.
TEMPS...VERY TRICKY FORECAST AS STRATUS DECK WILL PLAY A MAJOR
FACTOR. HAVE LOWERED TEMPS BY 3-5 DEGREES FROM PREVIOUS FORECAST
OVER THE NORTHERN WABASH VALLEY WHERE CONFIDENCE IS HIGHEST WITH
RESPECT TO CLOUD IMPACTS. SHOULD THE DECK HANG FOR LONGER...THESE
FORECAST HIGHS IN THE LOWER 40S ARE LIKELY TO BE TOO WARM. PLACED
TEMPS NEAR MOS GUIDANCE IN THE MID AND UPPER 40S ELSEWHERE.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AND
WEDNESDAY AS A SERIES OF WEAK UPPER LEVEL DISTURBANCES PASS THROUGH
THE LOWER GREAT LAKES.
HIGH PRESSURE RIDGE WILL BRING ANOTHER TRANQUIL NIGHT WITH CLEAR
SKIES TONIGHT. THE RIDGE SHIFTS EAST TUESDAY WITH MID AND HIGH LEVEL
CLOUDS EXPANDING INTO THE REGION FROM THE NORTHWEST. CHANCES FOR
PRECIPITATION ARE LIKELY TO HOLD OFF UNTIL TUESDAY EVENING AS LEAD
SHORTWAVE ASSOCIATED WITHIN LARGER UPPER TROUGH ROTATES ACROSS THE
REGION. ISENTROPIC LIFT AND OVERALL FORCING REMAIN GENERALLY
WEAK...BUT DOES APPEAR ENOUGH MOISTURE PRESENT FOR LIGHT
PRECIPITATION. WHILE A LIGHT RAIN/SNOW MIX IS POSSIBLE OVER SOUTHERN
COUNTIES TUESDAY EVENING...LOW LEVEL THERMALS AND MODEL SOUNDINGS
SHOW PRECIPITATION AS ALL SNOW AFTER MIDNIGHT AS THE BOUNDARY LAYER
AND NEAR SURFACE TEMPS COOL. SHORTWAVE AXIS SWINGS ACROSS THE
FORECAST AREA BETWEEN 06-12Z WEDNESDAY WITH BEST FORCING ALOFT. THIS
LIKELY TO BE THE TIMEFRAME WHEN LIGHT SNOW IS MOST PREVALENT WITH
HIGHEST POPS. APPEARS THERE COULD BE A FEW TENTHS OF AN INCH
ACCUMULATION BY DAYBREAK WEDNESDAY.
SCATTERED LIGHT SNOW SHOWERS WILL PERSIST WEDNESDAY MORNING WITH A
GRADUAL DIMINISHING OF COVERAGE AS BETTER MOISTURE AND FORCING SHIFT
EAST THROUGH THE DAY. CLOUDS AND A FEW FLURRIES LIKELY TO LINGER
UNTIL THE MAIN UPPER TROUGH PASSES WEDNESDAY AFTERNOON. WILL HOLD
ONTO LOW CHANCE POPS ON WEDNESDAY WITH MODEL SOUNDINGS FAVORING ANY
PRECIP TO FALL IN THE FORM OF LIGHT SNOW. NOT ANTICIPATING ANY
ADDITIONAL LIGHT ACCUMS AT THIS POINT. UPPER TROUGH MOVES AWAY TO
THE EAST WEDNESDAY WITH ANOTHER SURGE OF DEEP SUBSIDENCE ADVECTING
INTO THE REGION AS HIGH PRESSURE REESTABLISHES. SKIES SHOULD CLEAR
QUICKLY SETTING THE STAGE FOR A CHILLY NIGHT.
TEMPS...GENERALLY LEANED TOWARDS COOLER METMOS GUIDANCE THROUGH THE
PERIOD...ESPECIALLY TUESDAY NIGHT AND WEDNESDAY WITH CLOUDS AND
PRECIP. COLDEST NIGHT WILL BE WEDNESDAY NIGHT AS LOWS FALL TO NEAR
20 DEGREES UNDER CLEAR SKIES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
QUIET EXTENDED PERIOD FOR THE MOST PART...WITH THE ONLY EXCEPTION
BEING A VERY BROAD UPPER LEVEL TROUGH OVER MUCH OF THE GREAT LAKES
REGION AND MIDWEST ON FRIDAY/FRIDAY NIGHT. LATEST GFS AND EURO
MODEL RUNS ARE SHOWING MORE MOISTURE WITH AN ASSOCIATED COLD
FRONT...BUT INITIALIZATION NUMBERS ARE STILL TRENDING TOWARD A DRY
FRONTAL PASSAGE ON FRIDAY AFTERNOON/EVENING. AT THIS TIME...WILL
NOT MAKE ADJUSTMENTS TO INITIALIZATION NUMBERS UNTIL AFTER A FEW MORE
MODEL RUNS COME IN. OVERNIGHT LOWS WILL BE MORE REPRESENTATIVE FOR
THIS TIME OF YEAR WITH READINGS IN THE UPPER TEENS AND 20S DUE TO
THE CLEAR SKIES. THE AFOREMENTIONED COLD FRONT WILL LOWER DAYTIME
HIGHS A TAD ON SATURDAY...BUT THEY WILL QUICKLY INCREASE BACK INTO
THE UPPER 30S/LOW 40S BY SUNDAY AND MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 06/09Z TAF UPDATE/...
UPDATE...
FOG IS PROVING TO BE PROBLEMATIC AT KLAF AND KHUF WITH
VISIBILITIES IN THE LIFR/IFR CATEGORIES. ELSEWHERE...CONDITIONS
ARE HOLDING UP AT KIND AND KBMG...SO TEMPO MVFR THROUGH MON 13Z
STILL LOOKS REASONABLE AT THOSE SITES.
PREVIOUS DISCUSSION...
MAINLY VFR THROUGH THE PERIOD...WITH A PERIOD OF MVFR POSSIBLE NEAR
DAYBREAK TOMORROW.
HIGH PRESSURE HAS BUILT IN...ERODING ANY LEFTOVER CLOUD...AND
ALLOWING SIGNIFICANT DRYING AT THE SURFACE THROUGH A LIGHT NORTHERLY
SURFACE FLOW AND AMPLE SUNSHINE WITH THE SUPERB WEATHER YESTERDAY
AFTERNOON. ALTHOUGH WINDS WILL BE CALM TO LIGHT AND SKIES WILL BE
CLEAR OVERNIGHT...DO NOT EXPECT SIGNIFICANT FOG TO FORM. WILL
INCLUDE SOME HIGH END MVFR FOG FOR A FEW HOURS NEAR DAYBREAK AT ALL
SITES IN TEMPO GROUPS. NAM/RUC SOUNDINGS SHOW DECENT SATURATION NEAR
THE SURFACE...GFS/SREF SOUNDINGS DO NOT. NAM SOUNDING IS MOST
FAVORABLE...BUT ITS 00Z MOS DOES NOT BRING ANY RESTRICTIONS IN.
WINDS WILL BE CALM TO LIGHT OVERNIGHT...BECOMING WEST/SOUTHWESTERLY
TOMORROW BUT REMAINING BELOW 10KT. MAY SEE INFREQUENT GUSTS INTO THE
LOW TEENS BUT SURFACE PRESSURE GRADIENT APPEARS FAIRLY WEAK...SO
WILL NOT INCLUDE ANY MENTION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...NIELD/TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
345 AM EST MON FEB 6 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE IS GOING TO COVER INDIANA THROUGH MONDAY. A SERIES
OF WEAK DISTURBANCES WILL PASS OVERHEAD LATER THIS WEEK.
HOWEVER...HIGH PRESSURE WILL BE THE RULE AT THE SURFACE SO
PRECIPITATION CHANCES SHOULD STAY SMALL.
&&
.NEAR TERM /TONIGHT/...
MAIN ISSUES ARE TEMPERATURES AND FOG AS MODELS AND OBS ALL SUPPORT
CLEAR TONIGHT.
AT 01Z WINDS IN OBSERVATIONS INDICATED A WEAK SURFACE RIDGE TO OUR
WEST. RUC SAYS THIS WILL WORK EASTWARD AND ALMOST COMPLETELY KILL
OUR WINDS LATE TONIGHT. WITH THAT AND OUR CURRENT TEMPERATURES
ROUGHLY 3 DEGREES BELOW THE HOURLY GRIDS...I AM GOING TO DROP
MINS TONIGHT ABOUT A CATEGORY.
CLEAR WITH LIGHT WIND FAVORS FOG TONIGHT. BUFKIT SHOWS MOISTURE
DECREASING RAPIDLY WITH HEIGHT...A NEGATIVE. WITH OFFSETTING
FACTORS I WILL KEEP FOG IN THE FORECAST BUT WONT MENTION DENSE.
GIVEN DAMP GROUND WE MIGHT GET FOG OUTSIDE THE COMMON LOW SPOTS...SO
I WILL CHANGE COVERAGE TO AREAS FROM PATCHY.
&&
.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 THE 06/09Z TAF UPDATE/...
UPDATE...
FOG IS PROVING TO BE PROBLEMATIC AT KLAF AND KHUF WITH
VISIBILITIES IN THE LIFR/IFR CATEGORIES. ELSEWHERE...CONDITIONS
ARE HOLDING UP AT KIND AND KBMG...SO TEMPO MVFR THROUGH MON 13Z
STILL LOOKS REASONABLE.
PREVIOUS DISCUSSION...
MAINLY VFR THROUGH THE PERIOD...WITH A PERIOD OF MVFR POSSIBLE NEAR
DAYBREAK TOMORROW.
HIGH PRESSURE HAS BUILT IN...ERODING ANY LEFTOVER CLOUD...AND
ALLOWING SIGNIFICANT DRYING AT THE SURFACE THROUGH A LIGHT NORTHERLY
SURFACE FLOW AND AMPLE SUNSHINE WITH THE SUPERB WEATHER YESTERDAY
AFTERNOON. ALTHOUGH WINDS WILL BE CALM TO LIGHT AND SKIES WILL BE
CLEAR OVERNIGHT...DO NOT EXPECT SIGNIFICANT FOG TO FORM. WILL
INCLUDE SOME HIGH END MVFR FOG FOR A FEW HOURS NEAR DAYBREAK AT ALL
SITES IN TEMPO GROUPS. NAM/RUC SOUNDINGS SHOW DECENT SATURATION NEAR
THE SURFACE...GFS/SREF SOUNDINGS DO NOT. NAM SOUNDING IS MOST
FAVORABLE...BUT ITS 00Z MOS DOES NOT BRING ANY RESTRICTIONS IN.
WINDS WILL BE CALM TO LIGHT OVERNIGHT...BECOMING WEST/SOUTHWESTERLY
TOMORROW BUT REMAINING BELOW 10KT. MAY SEE INFREQUENT GUSTS INTO THE
LOW TEENS BUT SURFACE PRESSURE GRADIENT APPEARS FAIRLY WEAK...SO
WILL NOT INCLUDE ANY MENTION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...CP
LONG TERM....JH
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1138 PM EST SUN FEB 5 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE IS GOING TO COVER INDIANA THROUGH MONDAY. A SERIES
OF WEAK DISTURBANCES WILL PASS OVERHEAD LATER THIS WEEK.
HOWEVER...HIGH PRESSURE WILL BE THE RULE AT THE SURFACE SO
PRECIPITATION CHANCES SHOULD STAY SMALL.
&&
.NEAR TERM /TONIGHT/...
MAIN ISSUES ARE TEMPERATURES AND FOG AS MODELS AND OBS ALL SUPPORT
CLEAR TONIGHT.
AT 01Z WINDS IN OBSERVATIONS INDICATED A WEAK SURFACE RIDGE TO OUR
WEST. RUC SAYS THIS WILL WORK EASTWARD AND ALMOST COMPLETELY KILL
OUR WINDS LATE TONIGHT. WITH THAT AND OUR CURRENT TEMPERATURES
ROUGHLY 3 DEGREES BELOW THE HOURLY GRIDS...I AM GOING TO DROP
MINS TONIGHT ABOUT A CATEGORY.
CLEAR WITH LIGHT WIND FAVORS FOG TONIGHT. BUFKIT SHOWS MOISTURE
DECREASING RAPIDLY WITH HEIGHT...A NEGATIVE. WITH OFFSETTING
FACTORS I WILL KEEP FOG IN THE FORECAST BUT WONT MENTION DENSE.
GIVEN DAMP GROUND WE MIGHT GET FOG OUTSIDE THE COMMON LOW SPOTS...SO
I WILL CHANGE COVERAGE TO AREAS FROM PATCHY.
&&
.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 THE 06/06Z TAFS/...
MAINLY VFR THROUGH THE PERIOD...WITH A PERIOD OF MVFR POSSIBLE NEAR
DAYBREAK TOMORROW.
HIGH PRESSURE HAS BUILT IN...ERODING ANY LEFTOVER CLOUD...AND
ALLOWING SIGNIFICANT DRYING AT THE SURFACE THROUGH A LIGHT NORTHERLY
SURFACE FLOW AND AMPLE SUNSHINE WITH THE SUPERB WEATHER YESTERDAY
AFTERNOON. ALTHOUGH WINDS WILL BE CALM TO LIGHT AND SKIES WILL BE
CLEAR OVERNIGHT...DO NOT EXPECT SIGNIFICANT FOG TO FORM. WILL
INCLUDE SOME HIGH END MVFR FOG FOR A FEW HOURS NEAR DAYBREAK AT ALL
SITES IN TEMPO GROUPS. NAM/RUC SOUNDINGS SHOW DECENT SATURATION NEAR
THE SURFACE...GFS/SREF SOUNDINGS DO NOT. NAM SOUNDING IS MOST
FAVORABLE...BUT ITS 00Z MOS DOES NOT BRING ANY RESTRICTIONS IN.
WINDS WILL BE CALM TO LIGHT OVERNIGHT...BECOMING WEST/SOUTHWESTERLY
TOMORROW BUT REMAINING BELOW 10KT. MAY SEE INFREQUENT GUSTS INTO THE
LOW TEENS BUT SURFACE PRESSURE GRADIENT APPEARS FAIRLY WEAK...SO
WILL NOT INCLUDE ANY MENTION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...JK
NEAR TERM...JK
SHORT TERM...CP
LONG TERM....JH
AVIATION...NIELD
AREA FORECAST DISCUSSION
NWS QUAD CITIES IA IL
1136 PM CST SUN FEB 5 2012
.AVIATION...
LARGE AREA OF IFR/LIFR STRATUS AND LIGHT FOG REMAINS UNDER LOW
LEVEL INVERSION OF WEAK SURFACE HIGH PRESSURE OVER MOST OF IOWA.
TRENDS SUPPORTS CLOUD BASES OF 300 TO 900 FEET ALL TERMINALS REST
OF TONIGHT AND VISIBILITIES OF 3 TO 6 MILES DECREASING TO 1 TO 3
MILES AFTER MIDNIGHT. WESTERLY AND SOUTHWESTERLY WINDS TO BRING IN
MIXING AND DRIER AIR ACROSS ALL TERMINALS WITH CLEARING SKIES AND
7 MILES FOR VFR CONDITIONS BETWEEN 16-18Z. THEN...VFR CONDITIONS TO
CONTINUE AT LEAST THROUGH 07/06Z. ..NICHOLS..
&&
.PREV DISCUSSION... /ISSUED 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 TECHNIQUES 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..
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
NICHOLS
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
421 AM EST MON FEB 6 2012
.SYNOPSIS...
IN CONTRAST TO LAST COUPLE NIGHTS...CLEAR SKIES ARE DOMINANT ACROSS
UPR MI THIS MORNING. STRATUS IS NOT TOO FAR AWAY THOUGH OVR MN AND
WI. SO FAR...THERE IS ENOUGH WIND OVR UPR MI TO PROHIBIT THE STRATUS
FM SURGING INTO UPR MI. COLD FRONT THAT WILL BRING A CHANGE TO THE
RECENT UNSEAONABLE WARMTH IS DROPPING ACROSS MANITOBA AND ONTARIO
THIS MORNING. STRATOCU IS INITIAL SIGN OF THE COLDER AIR WITH SFC
OBS TURNING UP SOME LGT SNOW BEHIND THE FRONT OVR NORTHERN ONTARIO.
COLDER AIR ARRIVING LATE TODAY AND TONIGHT WILL LEAD TO LK EFFECT
SNOW SHOWERS OVR NORTHERN UPR MI. AS HAS BEEN CASE MUCH OF THIS
WINTER...THIS COOL DOWN WILL BE BRIEF WITH TEMPERATURES MOVING BACK
TOWARD NORMAL AS SOON AS WEDNESDAY. APPEARS THAT MORE SUBSTANTIAL
COOL DOWN WILL RETURN BY LATE WEEK INTO THE WEEKEND AS PORTION OF
POLAR VORTEX OVER EASTERN CANADA SLIDES INTO GREAT LAKES/NORTHEAST
CONUS.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...
IN THE NEAR TERM...QUIET CONDITIONS AS SKIES SHOULD STAY MOSTLY
CLEAR. RUC13 PERFORMED WELL WITH STRATUS YDY...AND IT DOES INDICATE
STRATUS MAY TRY TO MAKE MOVE INTO SW FRINGES OF UPR MI FM WISCONSIN.
SINCE RUC13 IS OVERDOING NORTHERN EXTENT TO CLOUDS AT THIS HOUR...WILL
KEEP WITH MAINLY CLEAR SKIES. DESPITE THE CLEAR SKIES...TEMPS ARE
STILL IN THE UPR 20S TO LOWER AND EVEN MID 30S WITH STEADY WEST WINDS
BLOWING AHEAD OF COLD FRONT DROPPING ACROSS ONTARIO. ISOLATED INLAND
LOCATIONS WHERE WINDS GO CALM COULD STILL FALL TO LOW-MID 20S THROUGH
SUNRISE /ALREADY HAVE SOME 25F READINGS AT WAKEFIELD AND DOE
LAKE/...BUT FOR LARGE PART TEMPS WILL REMAIN STEADY ELSEWHERE.
TODAY...
COLD FRONT FCST TO MOVE INTO FAR NORTH CWA TOWARD MIDDAY. FRONT
SHOULD REACH SOUTHERN CWA AROUND KMNM BY 21Z THIS AFTN. STRATOCU MAIN
ISSUE INITIALLY AS THERE IS NOT A LOT OF COLD AIR AROUND JUST IN WAKE
OF FRONT...WITH H85 TEMPS WARMER THAN -8C. KEPT ISOLATED SNOW SHOWERS
RESTRICTED TO NW CWA THIS AFTN AS COOLER AIR GRADUALLY FILTERS INTO
UPR MI. OTHERWISE...BASED ON UPSTREAM TRENDS IN ONTARIO THIS
MORNING...MOST AREAS COULD SEE SOME FLURRIES JUST IN WAKE OF FROPA.
TEMPS SHOULD FALL OFF WITH PASSAGE OF FROPA...BUT DOES APPEAR THAT
SHARPER COOLING IS LAGGING INITIAL SURGE OF STRATOCU BY A FEW HOURS.
HEADED TOWARD REGIONAL CANADIAN FOR TEMPERATURE TRENDS TODAY. BASED
ON WARM START THIS MORNING AND WEST WINDS ALREADY STIRRING...SEEMS
LIKELY THAT DOWNSLOPE AREAS OF CNTRL /MARQUETTE TO ESCANABA TO
MENOMINEE/ HAVE SHOT TO REACH INTO 40S BY EARLY AFTN JUST AHEAD OF
FRONT. BY LATE AFTN...EXPECT MOST AREAS TO BE AT OR BLO
FREEZING...WITH 20S LIKELY IN THE HIGHER TERRAIN OF NW AND NCNTRL UPR
MI.
TONIGHT INTO TUESDAY...
REALLY GOOD AGREEMENT ON SPECIFICS FM 00Z GUIDANCE WITH EXTENT AND
DEPTH OF COLD AIR /H85 TEMPS AROUND -15C/ AND MOISTURE /AT LEAST UP
TO 5KFT WHICH INTERSECTS IDEAL DENDRITIC SNOW GROWTH ZONE/. WIND
FIELDS ARE ALSO IN GOOD AGREEMENT WHICH IS A PLUS WHEN DEALING WITH
LK EFFECT. HAVE LEANED ON BLEND OF HIGHER RESOULTION 5KM NAM AND NCEP
HIGH RES WRF-ARW/NMM FOR POP/QPF DETAILS FOR LK EFFECT. IN REALITY
THIS DID NOT RESULT IN MUCH CHANGE TO PREVIOUS FCST. ONLY EXCEPTION
WAS TO TRIM LK EFFECT POPS BACK OVR MUCH OF GOGEBIC/ONTONAGON/IRON AS
BLYR WINDS ARE NOW NORTHEAST COMPARED TO NORTH. DIFFLUENCE SHOWS UP
IN WINDS OVR WESTERN INTERIOR UPR MI AS WELL...SUGGESTING THAT LK
EFFECT IN THE WEST SHOULD STAY PINNED CLOSER TO LK SUPERIOR SHORE
/KIWD THROUGH PORCUPINE MOUNTAINS AND ALONG SHORE AT ONTONAGON UP
INTO KEWEENAW/.
AT THE SAME TIME...LOW-LEVEL FLOW IS MORE CYCLONIC AND FM THE NNE
OVR NCNTRL CWA FOR MUCH OF THE NIGHT LEADING TO BETTER CHANCE OF
SEEING MODERATE SNOW AMOUNTS. FCST SOUNDINGS SHOW MOISTURE THROUGH H8
/7KFT/ THROUGH ABOUT 09Z THEN MOISTURE SETTLES BLO H85/5KFT TOWARD
DAYBREAK TUESDAY. OVER-WATER INSTABILITY IS SUFFICIENT FOR MODERATE
LAKE EFFECT AS LAKE INDUCED EQL RISE UP OVR 5KFT WITH SFC-H85 DELTA
T/S NEARING 20C. LK EFFECT SNOW PARAMETER PICKS UP ON THIS AND
DEEPER MOISTURE/UNIDIRECTIONAL LOW-LEVEL WINDS WITH POCKET OF HIGHER
VALUES BTWN 03Z AND 09Z TONIGHT. LOCAL LK EFFECT GUIDANCE SUGGESTS
12 HR SNOW AMOUNTS UP TO 6 INCHES IN THIS SETUP. UNDERCUT THIS
SLIGHTLY SINCE IDEAL LK EFFECT CONDITIONS WILL PROBABLY
ONLY BE REALIZED FOR 6-9 HRS DUE TO MARGINAL COLD AIR INITIALLY
TONIGHT AND DEEPER MOISTURE PULLING AWAY IN THE 09Z-12Z PERIOD.
THESE NEGATIVES MAY BE OFFSET BY HIGHER SLR/S AND FLUFFY NATURE OF
THE SNOW SINCE MAJORITY OF MOIST CONVECTIVE LAYER IS IN THE HEART OF
THE DGZ. SNOW RATIOS FM NAM COBB OUTPUT ARE IN THE 20-25:1.
EVEN AS DEEPER MOISTURE LEAVES FIRST THING TUESDAY MORNING...EXPECT
COVERAGE OF SNOW SHOWERS TO REMAIN HIGH THROUGH MOST OF TUESDAY
MORNING THOUGH INTENSITY SHOULD BE KNOCKED DOWN LARGELY DUE TO
INVERSIONS FALLING BLO 4KFT. OVERALL...TOTAL SNOW ACCUMS FM THIS
EVENING THROUGH EARLY TUESDAY AFTN COULD NEAR 6 INCHES IN SPOTS OVR
HIGHER TERRAIN FM HURON MOUNTAINS TO ISHPEMING/NEGAUNEE AND SKANDIA
AREAS AND INTO WESTERN ALGER COUNTY FM DEERTON TO CHATHAM. 12 HR
SNOW AMOUNTS ARE ONLY MARGINALLY SUFFICIENT FOR ADVY THOUGH AND
SINCE THERE IS NOT MUCH FOR ADDITIONAL HAZARDS /CONSIDERABLE BLSN
FOR EXAMPLE/ HAVE HELD OFF ON ISSUING ADVY ATTM. WILL LET DAYSHIFT
TAKE ONE MORE LOOK AT DETAILS AND PUT HEADLINE UP IF NEEDED. NORTH
WINDS BACK MORE NORTHWEST BY LATE TUESDAY AFTN...SHIFTING
DIMINISHING SNOW SHOWERS ACROSS MUCH OF ALGER COUNTY. AWAY FM
LK EFFECT TUESDAY...MAIN ISSUE WILL BE RETURN TO WINTER WITH
TEMPERATURES IN THE TEENS/20S AND WIND CHILL READINGS IN THE
SINGLE DIGITS ABOVE ZERO FOR MUCH OF THE DAY. BASICALLY THAT IS
FAIRLY TYPICAL FOR THIS TIME OF YEAR...BUT GIVEN THE RECENT WARMTH
IT WILL DEFINITELY FEEL ON THE CHILLY SIDE.
.LONG TERM /TUE NIGHT THRU SUN/...
TUE NIGHT...SHRTWV RDG/SFC HI PRES WL DOMINATE. WITH MOCLR SKIES...
LGT WINDS...AND PWAT AS LO AS 0.10-0.15 INCH OR 40-50 PCT OF
NORMAL...EXPECT TEMPS OVER THE INTERIOR SRN TIER TO DIP AOB THE LO
END OF GUIDANCE. AS THE SFC RDG SINKS SLOWLY TO THE S THRU THE
NGT...A STRONGER W WIND WITH H925 WINDS UP TO 30 KTS WL INFLUENCE
AREAS NEAR LK SUP AND LIMIT THE DIURNAL TEMP FALL THERE.
WED...CWA WL BE UNDER STRENGTHENING WLY FLOW/H925 WINDS UP TO 35 KTS
BTWN HI PRES RDG SINKING TOWARD THE OH RIVER VALLEY AND ANOTHER LO
PRES/ATTENDANT COLD FNT TRACKING ACRS NRN ONTARIO ASSOCIATED WITH
SHRTWV WITHIN DEEPENING UPR TROF OVER HUDSON BAY. WITH DRY
AIRMASS/PWAT ARND 0.15 INCH LINGERING...EXPECT A MOSUNNY DAY. H85
TEMPS ARE PROGGED TO REBOUND TO ARND -5C...SO THE DAY WL BE WARMER.
BUT GUSTY W WIND WL MAKE THE AIR FEEL COLDER DESPITE SLOWLY INCRSG
SOLAR ANGLE.
WED NIGHT...COLD FNT ASSOCIATED WITH DEEPENING UPR TROF CENTERED
NEAR HUDSON BAY IS FCST TO DROP INTO NRN LK SUP BY 12Z THU. LACK OF
ANY MSTR INFLOW/DRY NATURE OF ANTECEDENT AIRMASS ARGUES FOR A DRY
FCST WITH LTL IN THE WAY OF PRE-FRONTAL CLD COVER AS WELL...BUT DID
INTRODUCE SOME SCHC POPS OVER THE N HALF OF LK SUP OVERNGT TO MARK
ARRIVAL OF THIS FNT. ALTHOUGH PWAT IS FCST TO REMAIN LO ARND 0.15
INCH...STEADY W WIND WL LIMIT THE DIURNAL FALL OF TEMP.
EXTENDED...MODELS NOW IN GOOD AGREEMENT FOR THU SHOWING A SHARP COLD
FROPA WITH ONLY A WEAK SFC LO RUNNING ALONG THIS BNDRY...IN CONTRAST
TO SOME PAST MODEL RUNS THAT DEPICTED A DEEPER LO. WITH DRY AIRMASS
PRECEDING THE FROPA...WENT NO HIER THAN CHC POPS EVEN NEAR LK SUP.
INFUSION OF MUCH COLDER AIR BEHIND THIS FROPA WITH 00Z GFS SHOWING
H85 TEMPS FALLING AS LO AS -25C AND INVRN BASE ARND 5K FT WL RESULT
IN SOME LES...MOST PREVALENT IN AREAS FAVORED BY FCST NNW FLOW THRU
FRI. TENDED TO GO HIER THAN MODEL CONSENSUS POPS IN THESE FAVORED
AREAS GIVEN TENDENCY FOR MODELS TO UNDERDO LES. THEN AS ARCTIC HI
PRES DRIFTS SEWD TOWARD THE UPR MIDWEST ON SAT...BACKING FLOW TO
MORE W WL SHIFT THE LES INTO AREAS FAVORED BY THAT FLOW. LINGERING
LES SHOULD DIMINISH/END ON SUN AS UPR TROF LIFTS OUT/FLOW TURNS MORE
ACYC WITH HI PRES DRIFTING INTO THE OH RIVER VALLEY. NEAR NORMAL
TEMPS ON THU WL SINK AOB NORMAL THU NGT THRU SAT AS ARCTIC AIRMASS
INVADES THE UPR LKS. TEMPS WL REBOUND ON SUN WITH BLDG UPR RDG INTO
THE GRT LKS/RETURN LLVL SW FLOW OF WARMER AIR TO THE N OF SFC HI IN
THE OH VALLEY.
&&
.AVIATION /FOR THE 06Z TAF ISSUANCE/...
VFR CONDITIONS SHOULD PREVAIL THE REST OF TONIGHT AT ALL TAF SITES.
TIGHTER PRES GRADIENT BTWN HIGH PRES SINKING S THRU THE PLAINS AND A
COLD FRONT DROPPING S INTO NRN ONTARIO WILL RESULT IN LLWS OVERNIGHT
AT KIWD AND KSAW. FAVORABLE WRLY FLOW WILL KEEP WINDS GUSTY AT
KCMX...SO LLWS IS LESS LIKELY THERE. THE COLD FRONT WILL PASS THRU
THE TAF SITES MON MORNING...BRINGING MVFR CLOUD DECK AND PROBABLY
SOME FLURRIES OR -SHSN INTO MON EVENING.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT W WINDS UP TO 30 KTS EARLY TODAY TO WEAKEN A BIT WITH THE
APPROACH OF A COLD FRONT BUT THEN VEER TO THE N BY THIS EVNG AND
CRANK BACK UP TO 30 KTS FOLLOWING A COLD FRONTAL PASSAGE. THERE MAY
BE SOME GALE FORCE GUSTS TO 35 KTS AS WELL SINCE THE ARRIVAL OF MUCH
COLDER AIR OVER THE RELATIVELY WARM LAKE WATERS ENHANCES MIXING.
HOISTED A HEAVY FREEZING SPRAY WARNING FOR MUCH OF CENTRAL LAKE SUP
WITH INVASION OF ARCTIC AIR/HIER WAVES FORECAST IN THIS AREA INTO
TUE MORNING. THESE AUSTERE CONDITIONS WILL IMPROVE ON TUE WITH THE
ARRIVAL OF A HI PRES RIDGE/LIGHTER WINDS IN THE AFTERNOON. LIGHT
WINDS ON TUE EVENING ASSOCIATED WITH THE PASSING SFC HI PRES RIDGE
WILL INCREASE UP TO 30 KTS BY WED MORNING AS PRES GRADIENT SHARPENS
ONCE THE HI SINKS TOWARD THE OH RIVER VALLEY. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KTS OVER THE E WITH LONGER FETCH OF CHILLY
AIR OVER THE RELATIVELY WARM LAKE WATERS ALLOWING FOR MORE MIXING.
ALTHOUGH WINDS MAY DIMINISH LATE WED NIGHT INTO THU FOR A TIME AS
ONLY A WEAK LO PRES CENTER MOVES JUST TO THE NE OF THE LAKE...
EXPECT A STRONGER NNW FLOW TO 30 KTS TO DEVELOP FOLLOWING A COLD
FRONTAL PASSAGE ON THU. THE COMBINATION OF THESE STRONG WINDS AND
THE ARRIVAL OF VERY COLD AIR MAY RESULT IN HEAVY FREEZING SPRAY OVER
PORTIONS OF THE LAKE THRU THU NIGHT. THE CLOSER APPROACH OF A HI
PRES RIDGE WILL BRING DIMINISHING WINDS BY FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS
EVENING TO 10 AM EST /9 AM CST/ TUESDAY FOR LSZ241>244-263-
264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLA
SHORT TERM...JLA
LONG TERM...KC
AVIATION...VOSS
MARINE...KC
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
404 AM EST MON FEB 6 2012
LATEST UPDATE...ALL SECTIONS EXCEPT AVIATION...
.SYNOPSIS...(404 AM EST MON FEB 6 2012)
A COLD FRONT WILL CROSS THE REGION TONIGHT. THIS SYSTEM WILL BRING
VERY LITTLE SNOW...HOWEVER IT WILL RETURN TEMPERATURES TO NEAR
NORMAL VALUES FOR MID WEEK. ANOTHER SURGE OF COLDER AIR ARRIVES BY
FRIDAY AND INTO THE WEEKEND. SOME LAKE EFFECT SNOW SHOWERS WILL BE
SEEN ALONG WITH THIS COLDER AIR.
&&
.SHORT TERM...(404 AM EST MON FEB 6 2012)
(TODAY THROUGH WEDNESDAY)
THE SKY FORECAST REMAINS THE BIGGEST CHALLENGE TODAY AND THE
RESULTANT AFFECTS ON THE REGION/S TEMPS. A LARGE AREA OF STRATUS
COVERED MUCH OF WISCONSIN THIS MORNING AND IT WAS PRESSING EASTWARD
AT A 5-10 MPH PACE. THAT SPEED ALONG WOULD SUGGEST THAT THE CLOUD
DECK WOULD NOT REACH THE MICHIGAN SHORE UNTIL MID AFTERNOON.
HOWEVER THERE WAS ALSO RANDOM PATCHES OF STRATUS ACROSS LOWER
MICHIGAN TOO. THE RUC LOW LEVEL MOISTURE PROGS SUGGEST A RAPID
EXPANSION OF THE STRATUS SO THAT THE ENTIRE GRR CWA IS COVERED BY
CLOUDS BY 12Z. THIS LOOKS UNREASONABLE TO ME. HOWEVER BELIEVE THE
STRATUS WILL LIKELY SPEED UP IT/S EASTWARD TRACK AS IT MOVES ACROSS
THE LAKE THIS MORNING. ALSO...THE RANDOM PATCHES MAY ALSO EXPAND
SOMEWHAT THIS MORNING. BUT THEN THE ISSUE BECOMES...WHAT WILL THE
INCREASED MIXING DO TO THE STRATUS. I SENSE THAT IT WILL HELP IT TO
ERODE SUCH THAT MUCH OF THE STRATUS BECOMES LESS OF A FACTOR BY MID
DAY. SO I WILL PLAY THE FORECAST SUCH THAT SOME STRATUS WILL LINGER
THROUGH THE MORNING...BUT WILL BANK ON A MOSTLY SUNNY AFTERNOON AS
THE EASTWARD EDGE OF THE STRATUS MIXES OUT. IF THIS INDEED OCCURS
TEMPS WILL REACH WELL INTO THE 40S AGAIN TODAY...IF IT DOES NOT
OCCUR TEMPS MAY HOLD FROM 35 TO 40.
THE ARCTIC FRONT IS STILL ON SCHEDULE FOR TONIGHT. THE LACK OF DEEP
MOISTURE WILL RESULT IN NO SNOW OR PERHAPS A RANDOM FLURRY. THE LOW
LEVEL FLOW BEHIND THE FRONT SHOULD BE 030-040...KEEPING ANY LAKE
EFFECT ON THE OTHER SIDE OF THE LAKE. WE WILL HAVE TO KEEP AN EYE
ON POSSIBLE SNOW SHOWERS OFF OF SAGINAW BAY WHICH MAY MOVE INTO
AREAS AROUND ST. JOHNS BY TUESDAY.
HAVE LOW POPS IN FOR TUE AFTERNOON INTO TUESDAY NIGHT FOR AREAS
SOUTH OF I-96. A SHORT WAVE COMES ACROSS THE LOWER GREAT LAKES AND
COMBINED WITH THE EXITING ARCTIC FRONT MAY PRODUCE SOME LIGHT SNOW.
LOW LEVEL WINDS SHOULD ALSO BACK TO THE NW BY LATE TUESDAY NIGHT
WHICH COULD BRING A FEW SNOW SHOWERS OFF THE LAKE. BY WEDNESDAY THE
MOISTURE PROFILE BECOMES VERY SHALLOW AS RIDGING BUILDS INTO THE
AREA. EXPECT SUNSHINE WITH NEAR NORMAL TEMPS.
&&
.LONG TERM...(404 AM EST MON FEB 6 2012)
(WEDNESDAY NIGHT THROUGH SUNDAY)
A CLIPPER MOVES ACROSS NORTHERN LOWER MICHIGAN THURSDAY NIGHT
SWINGING AN ARCTIC FRONT SOUTH ACROSS THE FORECAST AREA.
LOOKS LIKE SOME SNOW WILL ACCOMPANY THE FROPA WITH STRONG SFC
CONVERGENCE. LAKE EFFECT BEHIND THE FRONT WILL CONTINUE INTO
SATURDAY BUT FLOW GOES NORTH AND THEN EVENTUALLY NORTHEAST WHICH
WOULD PUSH THE SNOW SHOWERS OFFSHORE. THIS COMBINED WITH INVERSION
HEIGHTS BELOW 10 KFT SHOULD LIMIT ACCUMS...WITH MOST OF THE SNOW
CONCENTRATED FAIRLY CLOSE TO THE LAKE MICHIGAN SHORE.
&&
.AVIATION...(1156 PM EST SUN FEB 5 2012)
MVFR CLOUDS WERE ON THE INCREASE FROM KMKG TO KRQB. THIS BAND WAS
SHIFTING SOUTHEAST AND WILL LIKELY IMPACT THE TAF SITES FOR A FEW
HOURS TONIGHT. TOWARD DAYBREAK THE MORE SIGNIFICANT AREA OF IFR OR
LOWER CLOUDS IN WI...WILL BE ARRIVING IN KMKG. THEY WILL CONTINUE
EAST AND SOME UNCERTAINTY EXISTS AS TO HOW FAR EAST THEY WILL GO. I
DID LOWER ALL BUT KLAN AND KJXN DOWN TO IFR FOR MON AM INTO THE
EARLY AFTERNOON HOURS. SOME INDICATIONS THE MOISTURE WILL TRY TO
THIN OUT DURING THE AFTERNOON. A THICKER BAND OF CLOUDS AND PERHAPS
FZDZ WILL ARRIVE OF MON NIGHT. I DID NOT INCLUDE THE FZDZ WITH THIS
FORECAST...BUT THERE IS AT LEAST A LOW RISK AT THIS POINT.
&&
.MARINE...(404 AM EST MON FEB 6 2012)
SCA IN AFFECT FOR TODAY WITH WSW WINDS TO AROUND 20 KTS. LOOKS LIKE
WE WILL SEE A BRIEF BREAK IN THE HIGHER WINDS AND WAVES EARLY
TONIGHT AS A COLD FRONT COMES THROUGH. BUT THEN BEHIND THE FRONT
WAVES SHOULD INCREASE AGAIN LATE TONIGHT OR EARLY TUESDAY IN THE
COLD ADVECTION PATTERN.
&&
.HYDROLOGY...(404 AM EST MON FEB 6 2012)
MINIMAL HYDRO CONCERNS GIVEN THE LACK OF PCPN. ALSO THE SNOW PACK
TO THE NORTH WILL END IT/S MELTING BY TONIGHT AS THE COLD FRONT
COOLS REGIONAL TEMPS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY ST. JOE TO MANISTEE THROUGH TODAY.
&&
$$
SYNOPSIS: JK
SHORT TERM: JK
LONG TERM: OSTUNO
AVIATION: MJS
MARINE: JK
HYDROLOGY: JK
AREA FORECAST DISCUSSION
NWS GAYLORD MI
347 AM EST MON FEB 6 2012
.SYNOPSIS.../ISSUED AT 347 AM/
HIGH PRESSURE ACROSS THE REGION THROUGH MIDDAY WILL GIVE WAY TO AN
APPROACHING COLD FRONT BY EVENING. THE PASSAGE OF THIS FRONT WILL
USHER IN A BRIEF SHOT OF MUCH COLDER WEATHER FOR THE DAY ON
TUESDAY...ALONG WITH CHANCES FOR SOME LIGHT SNOW SHOWERS.
TEMPERATURES WILL WARM BACK ABOVE NORMAL BY THURSDAY AS HIGH
PRESSURE AGAIN ARRIVES...BEFORE ANOTHER PUSH OF COLD WEATHER AND
LAKE SNOW SHOWERS ARRIVES FOR FRIDAY INTO THE WEEKEND.
DL
&&
.SHORT TERM.../ISSUED AT 347 AM/...TODAY
A SHARP COLD FRONT IS MOVING SOUTH TOWARD THE NORTH SHORE OF
SUPERIOR EARLY THIS MORNING. THERE IS NO PRECIP...AND IN FACT NO
CLOUDS...WITH THE FRONT ITSELF...THOUGH LOW CLOUDS ARE EXTENSIVE
BEHIND IT. IN THE WARM SECTOR...A FEW PATCHES OF LOW CLOUDS REMAIN
OVER MI AND ENVIRONS...WITH MORE WIDESPREAD CLOUD COVER IN THE UPPER
MS VALLEY AND EXPANDING ESE-WARD. CLOUD/TEMP TRENDS ARE AGAIN
THE MAIN CONCERN TODAY.
COLD FRONT WILL REACH EASTERN UPPER MI TOWARD 18Z...AND WILL BE
NEARING SAGINAW BAY AT 00Z. OUTSIDE OF VERY SHALLOW SURFACE-BASED
MOISTURE...THE DEEP AIRMASS IN THE WARM SECTOR REMAINS VERY DRY
(850-700MB RH LESS THAN 30 PERCENT...PWATS 0.25-0.30). THERE IS NO
RISK OF PRECIP AHEAD OF...OR WITH...THE FRONT. HOWEVER...CLOUD
TRENDS IN THE WARM SECTOR REMAIN PROBLEMATIC. THE AIRMASS BELOW
925MB REMAINS MOIST (SURFACE DEW POINTS REFLECT THIS). LARGER LOW
CLOUD MASS TO OUR WEST IS TRYING TO WORK EAST THIS MORNING...BEFORE
MIXING CAN EAT AWAY AT IT TOO MUCH. DOWNSLOPING WINDS INTO FAR
EASTERN WI ARE KEEPING THE CLOUD MASS FROM ADVANCING AS FAR EAST AS
IT COULD. MODEL GUIDANCE IS ALL OVER THE MAP...FROM THE NAM NOT
ALLOWING ANY LOW CLOUDS TO CROSS THE LAKE...TO THE HRRR WHICH
COMPLETELY SOCKS IN ALL OF NORTHERN MI BY 16Z.
GIVEN SATELLITE TRENDS OF AN CLOUD MASS CLEARLY STRUGGLING TO MOVE
EAST...WILL NOT BRING IN OVERCAST SKIES THIS MORNING. WE/RE STILL
PLENTY MOIST DOWN LOW...AND SMALL PATCHES OF LOW CLOUDS COULD FORM
JUST ABOUT ANYWHERE THIS MORNING. WE MAY ALSO BE NEED MOIST ENOUGH
TO QUICKLY FIRE A SHALLOW CU DECK BEFORE MIXING IT OUT TOWARD
MIDDAY.
BEHIND THE FRONT...LOW CLOUDS WILL BECOME EXTENSIVE FROM NORTH TO
SOUTH DURING THE AFTERNOON. THERE MAY BE AN OUTSIDE SHOT AT A BIT OF
DRIZZLE OR SOME FLURRIES IN CENTRAL/WESTERN CHIPPEWA CO VERY LATE.
INVERSION-TOP (875MB) TEMPS REACH -7/8C (SO DELTA T/S INTO THE LOWER
TEENS).
MAX TEMPS WILL AGAIN BE QUITE MILD. WILL FAVOR WARMER GUIDANCE
NUMBERS GIVEN A BALMY START TO THE DAY. MAX TEMPS MID/UPPER 30S
NORTH TO MID 40S FAR SE.
JZ
&&
.LONG TERM.../ISSUED AT 347 AM/...TONIGHT AND BEYOND
THE UPPER TROF FORCING TODAY/S COLD FRONT WON/T ACTUALLY MAKE IT TO
OUR NEIGHBORHOOD UNTIL LATE TUESDAY. LOW LEVEL COLD ADVECTION WILL
CONTINUE UNTIL THEN (THOUGH THE AIRMASS SHOULD MODERATE WITH SOME
SUNSHINE TUESDAY). DESPITE REASONABLE INSTABILITY...THE POOR NORTH
FETCH...LACK OF MOISTURE...AND ARRIVAL OF SURFACE RIDGING/
ANTICYCLONIC CURVATURE WILL LIMIT LAKE EFFECT SNOW (LES) POTENTIAL.
AS HIGH PRESSURE PRESSES SOUTH INTO THE CENTRAL PLAINS BY
WEDNESDAY...WESTERLY LOW LEVEL FLOW AND WARM ADVECTION WILL AGAIN BE
RE-ESTABLISHED HERE. THAT WILL BE BRIEF...AS A STRONGER SHOT OF COLD
AIR APPEARS LIKELY AT THE END OF THE WORK WEEK. TEMP/PRECIP
TRENDS...MAINLY ASSOCIATED WITH THE COLD AIR TONIGHT/TUESDAY AND
AGAIN AT THE END OF THE WEEK...ARE THE MAIN CONCERNS.
TONIGHT...COLD FRONT WILL MOVE SOUTH OF MI...WHILE 500MB TROF WILL
ADVANCE TO NORTHERN SUPERIOR. SURFACE HIGH PRESSURE WILL MOVE INTO
ND...WITH RIDGING EXTENDING JUST NORTH OF SUPERIOR. 1000-850MB WINDS
WILL BECOME N/NNW BY 03Z...AND N/NNE BY 12Z. WE DO MANAGE TO GET
850-700MB RH LEVELS UP TO 60 PERCENT OR SO...IN THE EVENING AROUND
EASTERN UPPER...EXPANDING SOUTH OVERNIGHT (DRYING OUT ON EASTERN
SUPERIOR TOWARD 12Z). DELTA T/S REACH IN THE MID TEENS IN THE
OVERNIGHT HOURS...WHICH SHOULD SPOT OUT A FEW SNOW SHOWERS IN FAR
WESTERN AND FAR EASTERN SECTIONS OF THE FORECAST AREA (GIVEN
UNFAVORABLE N FETCH). WILL KEEP POPS QUITE SMALL...NAM/LOCAL WRF IN
EXCELLENT AGREEMENT IN GENERATING NO QPF ANYWHERE IN THE FORECAST
AREA TONIGHT. MEANWHILE...THE I-75/US-127 CORRIDOR IN NORTHERN
LOWER...AND FAR EASTERN UPPER...SHOULD CLEAR PARTIAL CLEARING. MIN
TEMPS WILL RANGE FROM MID/UPPER SINGLE DIGITS IN FAR EASTERN
UPPER...TO LOWER 20S IN SOME SOUTHERN SECTIONS.
TUESDAY...THE MAIN FACTOR IS THE STRONG SURFACE RIDGE THAT CROSSES
SUPERIOR AND SETTLES ACROSS UPPER/FAR NORTHERN LOWER MI BY 00Z.
ASSOCIATED DRYING (850-700MB RH GO BELOW 25 PERCENT) AND
ANTICYCLONICALLY CURVED FLOW WILL COMPLETELY PUT THE KIBOSH ON LES
AS THE DAY PROCEEDS...DESPITE CONTINUED PRESENCE OF CHILLY AIR
(DELTA T/S MID TEENS). EXPECT CLOUD COVER TO ERODE AS WELL AS WE
MOVE THRU THE AFTERNOON. WILL CONTINUE WITH A SMALL CHANCE OF -SHSN
IN THE MORNING ALONG WESTERN AND EASTERN FRINGES OF THE FORECAST
AREA...AND GO DRY IN THE AFTERNOON. MAX TEMPS UPPER TEENS TO MID 20S.
TUE NIGHT THRU WED NIGHT...SURFACE RIDGE AXIS WILL CONTINUE TO MOVE
SOUTH ACROSS LOWER MI TUESDAY NIGHT...AND WILL EVENTUALLY REACH THE
OHIO VALLEY BY THURSDAY MORNING. BY THEN...THE NEXT COLD FRONT WILL
BE REACHING SUPERIOR. IN BETWEEN...WESTERLY 1000-850MB WINDS WILL
KICK THE COLD AIR OUT FOR A BIT...WITH 850MB TEMPS REACHING -6C BY
WEDNESDAY EVENING. THIS AIRMASS WILL REMAIN QUITE DRY IN THE MID AND
UPPER LEVELS...THOUGH WE MAY AGAIN BE CONTENDING WITH OCCASIONAL LOW
CLOUD ISSUES (ESPECIALLY WEDNESDAY NIGHT) LIKE WE/VE SEEN THE LAST
SEVERAL DAYS. STILL...PARTLY CLOUDY TO MOSTLY CLEAR WILL COVER MUCH
OF THESE PERIODS...WITH NO RISK FOR PRECIP. MIN TEMPS WILL BE QUITE
CHILLY TUE NIGHT...SINGLE DIGITS TO MID TEENS. MAX TEMPS WEDNESDAY
MID 20S TO LOWER 30S. MIN TEMPS WED NIGHT MID TEENS TO LOWER 20S.
JZ
LATER PERIODS (THURSDAY THROUGH SUNDAY)...BRIEF PATTERN CHANGE STILL
ANTICIPATED HEADING INTO THE WEEKEND...AS STRONG MERIDIONAL RIDGING
BUILDING UP THE WEST COAST OF NORTH AMERICA BRIEFLY DISLODGES THE
POLAR VORTEX TOWARD HUDSON BAY. HOWEVER...AS MENTIONED IN THIS SPACE
SEVERAL TIMES THE PAST FEW DAYS...THE PATTERN CHANGE STILL LOOKS TO
BE VERY BRIEF...WITH THE COLDEST AIR RELEGATED TO FRIDAY AND
SATURDAY DAY WHEN H8 TEMPS ARE STILL PROGGED BY MAJORITY OF 00Z
GUIDANCE TO DIP TO AROUND -21C OR SO AT THEIR COLDEST. OVERALL
HEMISPHERIC PATTERN DURING THE WEEKEND TIMEFRAME IS RATHER
UNSTABLE...FEATURING A WAVERING 3-4 WAVE PATTERN...AND THUS NO REAL
SURPRISE TO SEE GUIDANCE CONTINUING EARLIER TRENDS OF ERASING THE
BRIEF PATTERN SHIFT AS STRONG PACIFIC JET ENERGY AGAIN PLOWS THROUGH
MUCH OF THE CONUS. THIS SHOULD RAPIDLY SHIFT THE CORE OF COLDEST AIR
TO THE EAST BY SUNDAY...WITH THE STRONG POSSIBILITY FOR ANOTHER
ROUND OF QUITE WARM WEATHER (BY FEBRUARY STANDARDS AT LEAST) TO
ARRIVE INTO THE FOLLOWING WEEK...THOUGH THAT`S GETTING A BIT AHEAD
OF THINGS FOR THIS FCST.
LOOKING AT THE SPECIFICS...STILL LOOKS LIKE A PERIOD OF SOME LAKE
EFFECT SNOW SHOWERS (BASICALLY A GIVEN) AS COLDER AIR POURS INTO THE
AREA LATER THURSDAY THROUGH SATURDAY...WITH TRENDS THE PAST FEW DAYS
STILL SUGGESTING A MEAN NORTHERLY COMPONENT TO THE LOW LEVEL FLOW.
THAT SAID...MESOSCALE PROCESSES MAY INCREASINGLY COME INTO PLAY BY
SATURDAY AS LOW LEVEL FLOW BECOMES INCREASINGLY ANTICYCLONIC BUT
OVERLAKE INSTABILITY REMAINS STELLAR. WHILE OVERALL MOISTURE
PROFILES DURING THE FRIDAY/SATURDAY TIMEFRAME ARE NOTHING REALLY
IMPRESSIVE...DEPTH OF THE DGZ THROUGH THE LAKE-INDUCED CLOUD LAYER
DOES ARGUE THAT SOME LOCALIZED MODEST FLUFFY ACCUMULATIONS WILL BE
POSSIBLE...MAINLY DOWNWIND OF GRAND TRAVERSE BAY AND PERHAPS INTO
FAR NORTHWESTERN CHIPPEWA COUNTY. SNOW SHOWER CHANCES WILL DWINDLE
QUICKLY HEADING THROUGH THE DAY ON SUNDAY AS LOW LEVEL INSTABILITY
WANES...WITH AN OVERWHELMING MAJORITY OF GUIDANCE SIGNALS SUGGESTING
H8 TEMPS MODIFY INTO THE SINGLE DIGITS BELOW ZERO BY 00Z MONDAY.
TEMPS THROUGH THE EXTENDED WILL FINALLY BE A BIT BELOW NORMAL FOR
ONCE.
LAWRENCE
&&
.MARINE.../ISSUED AT 347 AM/
SOMEWHAT BLUSTERY WEST WINDS WILL CONTINUE UNTIL A COLD FRONT...NOW
NEARING SUPERIOR...CROSSES NORTHERN MI THIS AFTERNOON AND EARLY
EVENING. SMALL CRAFT ADVISORIES ALREADY UP FOR ALL WATERS...AND WILL
REMAIN UNCHANGED. COLD NORTH WINDS MAY SUPPORT ADVISORIES INTO
TONIGHT (ESPECIALLY AS INSTABILITY INCREASES)...BUT WILL HOLD OFF ON
ANY EXTENSIONS AT THIS TIME.
JZ
&&
.AVIATION.../ISSUED AT 1150 PM/...VALID FOR 06Z TAFS
A MAINLY SCATTERED DECK OF MVFR SC ACROSS NW LWR MICHIGAN
(PLN/TVC/MBL) WILL TEMPORARILY BECOME BKN VERY LATE TONIGHT/EARLY
MONDAY MORNING AS THE ERN EDGE OF A PERSISTENT LOW STRATUS DECK OVER
WISCONSIN TRIES TO PUSH INTO LWR MICHIGAN. DAYTIME MIXING SHOULD
ERODE THE ERN EDGE OF THE STRATUS DECK...WITH VFR CONDITIONS
RETURNING TO NW LWR MICHIGAN BY AROUND LATE MORNING. ADDITIONAL LOW
CLOUDS WILL DROP SOUTH OUT OF ONTARIO INTO NRN MICHIGAN DURING LATE
AFTERNOON/EARLY EVENING ALONG AND BEHIND A COLD FRONT. LLWS IS
EXPECTED AT ALL TAF SITES UNTIL AROUND MID MORNING.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
LMZ323-341-342-344>346.
LS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1155 PM EST SUN FEB 5 2012
LATEST UPDATE...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...(1155 PM EST SUN FEB 5 2012)
MVFR CLOUDS WERE ON THE INCREASE FROM KMKG TO KRQB. THIS BAND WAS
SHIFTING SOUTHEAST AND WILL LIKELY IMPACT THE TAF SITES FOR A FEW
HOURS TONIGHT. TOWARD DAYBREAK THE MORE SIGNIFICANT AREA OF IFR OR
LOWER CLOUDS IN WI...WILL BE ARRIVING IN KMKG. THEY WILL CONTINUE
EAST AND SOME UNCERTAINTY EXISTS AS TO HOW FAR EAST THEY WILL GO. I
DID LOWER ALL BUT KLAN AND KJXN DOWN TO IFR FOR MON AM INTO THE
EARLY AFTERNOON HOURS. SOME INDICATIONS THE MOISTURE WILL TRY TO
THIN OUT DURING THE AFTERNOON. A THICKER BAND OF CLOUDS AND PERHAPS
FZDZ WILL ARRIVE OF MON NIGHT. I DID NOT INCLUDE THE FZDZ WITH THIS
FORECAST...BUT THERE IS AT LEAST A LOW RISK AT THIS POINT.
&&
.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: MJS
MARINE: DUKE
HYDROLOGY: DUKE
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
322 AM CST MON FEB 6 2012
.DISCUSSION...
STILL A COMPLICATED CLOUD TREND THIS MORNING. THERE DOES SEEM TO
BE A BIT STRONGER EASTWARD PUSH OF THE CLOUD EDGE WEST OF MSP PER
THE MORE WEST COMPONENT SEEN IN THE LOW LEVELS. A DIFFERENT STORY
OVER FAR SOUTHERN MN. THAT EDGE HAS A SLOW NORTHWARD DRIFT WHICH
MAY CONTINUE AND PROBABLY KEEP SOUTH CENTRAL MN AND PARTS OF
WEST CENTRAL WI IN THE CLOUDS THOUGH THE MORNING. THE HRRR HAS HAD
THE BEST TREND ON THE LOW CLOUDS SINCE YESTERDAY...SO WILL TRY TO
FOLLOW THIS IN THE VERY SHORT TERM. THIS WILL OBVIOUSLY HAVE
IMPLICATIONS ON THE HOURLY TEMP TRENDS.
THE ARCTIC FRONT IS WELL MARKED WITH THE CLOUDS EDGE PUSHING
SOUTH OVER SOUTHERN CANADA..WILL WORK INTO OUR NORTHERN AREAS
THIS AFTERNOON. WILL USE MORE OF A MODEL DIURNAL TEMP TREND TODAY
WITH HIGHS REACHED EARLY IN THE FAR NORTHWEST ALONG WITH THE CLOUD
ISSUES IN THE SOUTH. STILL A DECENT CHANCE OF 40S FOR HIGHS IN THE
SOUTH. SOME MINOR LIFT WITH THE FRONT TONIGHT...AND THERE IS A
HINT OF PV ADVECTION LATE TONIGHT OVER FAR SOUTHERN MN FROM THE
SYSTEM TO OUR SOUTHWEST. WILL KEEP THE FLURRIES IN THE FORECAST
TONIGHT AND TUESDAY MORNING WITH THE FRONT AND WAIT ON THE
POSSIBILITY OF A SLIGHT CHANCE POP IN THE FAR SOUTH. THERE IS A
MINOR RISK OF FREEZING DRIZZLE WITH LACK OF MID LEVEL MOISTURE
UNTIL TUESDAY MORNING...BUT WITH A TIMING AN LOCATION
ISSUE...WILL WAIT ON THAT AS WELL.
A STRONGER FRONT STILL FORECAST TO AFFECT THE AREA THURSDAY AND
FRIDAY AND THE ECMWF HAS COME AROUND A LITTLE MORE IN LINE TO THE
GFS/GEM WITH THE STRENGTH. STILL A FAIR AMOUNT OF UNCERTAINTY IN
THE GFS ENSEMBLE TEMPS STARTING FRIDAY AND CONTINUING INTO THE
WEEKEND. EVEN THOUGH THE ECMWF LOOKS COLD FOR FRIDAY...IT`S TREND
FOR A GLANCING BLOW IS STILL THERE WITH A FLATTENING OF THE RIDGE
OUT WEST DURING THE WEEKEND. OUR CURRENT BLENDED FORECAST FOR
FRIDAY TEMPS MAY BE A BIT HIGH BUT THAT CAN STILL BE ADDRESSED IN
THE NEXT DAY OR TWO.
&&
.AVIATION.../06Z TAF ISSUANCE/
PERSISTENT LOW CLDS/FG ACROSS THE EASTERN FA IS THE MAIN CONCERN
IS THE SHORT TERM AND WHETHER STRONGER SW FLOW IN THE BOUNDARY
LAYER DEVELOPING...WILL ALLOW FOR THE CLDS TO MOVE OUT DURING THE
NEXT 6 TO 12 HRS.
BASED ON CURRENT SATELLITE TRENDS OVER THE PAST FEW HRS...AND
BOUNDARY LAYER MOISTURE REMAINING HIGH...MSP/RNH/EAU WILL LIKELY
CONTINUE THE IFR/LIFR CIGS THRU 12Z...WITH A SLOW EROSION FROM THE
WEST/NW AS A COLD FRONT MOVES ACROSS THE AREA BY AFTN.
LATEST RUC HAS A GOOD HANDLE ON THE LOW LEVEL MOISTURE AND
ASSOCIATED CLDS...BUT IT CONTINUES TO DECREASE THE CLDS FROM THE
WEST TOO FAST THAN CURRENTLY INDICATED. WITH SOME UNCERTAINTY PAST
12Z...WILL HOLD ON TO LIFR/IFR CIGS AT RNH/EAU UNTIL WNDS SHIFT TO
THE W/NW BY NOON. RWF/AXN/STC WILL LIKELY SEE SOME BR/FG THIS
MORNING...BUT ENOUGH MIXING IN THE BOUNDARY LAYER SHOULD PRECLUDE
ANY SIGNIFICANT DENSE FG BY MORNING. CIGS ACROSS FAR SW MN MAY
AFFECT RWF BY 12Z...BUT WNDS ARE NOT CONDUCIVE FROM THE BOUNDARY
LAYER TO ADV THESE CLDS TO THE NE THIS MORNING. TIMING OF THE
COLD FRONT AND ASSOCIATED MVFR CIGS ARE CLOSE TO PREVIOUS TAFS.
THE ONSET OF MVFR CIGS MAY BE A BIT TOO FAST BASED ON UPSTREAM
CLDS. WNDS WILL BECOME W/WNW THIS DURING THE MORNING...THEN SHIFT
TO THE N/NNE AND INCREASE DURING THE AFTN/EVENING.
MSP...THRU 12Z...IFR CIGS AND VSBYS ARND 3-5SM WILL CONTINUE. BY
12Z...SOME UNCERTAINTY EXIST IF THE WESTERN EDGE OF THE CLDS WILL
MOVE FAR ENOUGH EAST TO BECOME SCT008 AT THE AIR FIELD.
THEREFORE...INCLUDED A TEMPORARY PERIOD OF POSSIBLE VFR BETWEEN
11-15Z. MVFR CIGS WILL ONCE AGAIN ADV BACK ACROSS THE REGION BY
AFTN AS A COLD FRONT MOVES SOUTHWARD. WNDS WILL BECOME MORE W/WNW
BY 12Z...THEN SHIFT TO THE NW AFT 18Z. WNDS SHOULD INCREASE IN SPD
BY 22-01Z...WITH A FEW GUSTS OVER 20 KTS POSSIBLE.
.TUE...MVFR CIGS EARLY WITH -SN POSSIBLE.
.WED...VFR.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/JLT
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
1126 PM CST SUN FEB 5 2012
.DISCUSSION...
THIS FORECAST NOT MUCH MORE THAN A CLOUD AND TEMPERATURE
FORECAST...WITH A CONTINUED DRY PATTERN EXPECTED FOR THE NEXT WEEK.
MILD CONDITIONS WILL PERSISTENT THROUGH MONDAY...WITH A COOL DOWN
EXPECTED FOR TUESDAY THROUGH FRIDAY...WITH A WARM UP OF SOME DEGREE
COMING FOR THE WEEKEND.
RATHER UNIQUE UPPER AIR PATTERN EXISTS THIS AFTERNOON...WITH A REX
BLOCK PATTERN IN PLACE ACROSS THE ROCKIES. MPX CWA CAUGHT IN A WEAK
FORCING AREA BETWEEN THE CUT OFF LOW OVER THE ROCKIES...THE REMNANTS
OF THE PLAINS SNOW STORM OVER MO...AND THE MAIN UPPER FLOW ACROSS MB
AND ONT. THIS HAS ONCE AGAIN LEFT LOW STRATUS ADRIFT ACROSS THE AREA
TODAY...WITHOUT MUCH FORCING TO GET RID OF IT. PIREPS THIS MORNING
SHOWED CLOUDS OVER THE TWIN CITIES WERE AROUND 2K FT DEEP...AND AS A
RESULT...HAS BEEN A SLOW GO IN CLEARING THINGS OUT THIS AFTERNOON.
FOR SKY GRIDS...ABOUT THE ONLY BIT OF GUIDANCE THAT HAD ANY IDEA THE
STRATUS WAS OUT THERE WAS THE LOCAL MPX WRF...SO FOLLOWED IT FOR
SLOWLY WORKING CLOUDS SE ACROSS THE AREA TONIGHT. HAVE CLOUDY
CONDITIONS REMAINING ACROSS SE CWA INTO MONDAY MORNING...WITH MO
CLEAR TO PRTLY CLOUDY CONDITIONS ELSEWHERE BY MONDAY MORNING...BUT
MUST ADMIT...NOT COMPLETELY CONVINCED THAT CLOUDS WILL NOT START
BUILDING BACK WEST/NORTH ONCE THE SUN SETS. REGARDLESS OF CLOUD
COVER...TONIGHT WILL BE A MILD ONE...AS BUBBLE OF WARM AIR THAT WAS
OFF TO OUR NW THIS MORNING /+8C AT H85 AT THE PAS...MB AT 12Z/ WILL
BE MOVING OVHD TONIGHT OUT AHEAD OF THE ARCTIC FRONT COMING MONDAY.
BY 12Z MONDAY MORNING...COLD FRONT WILL BE ALONG THE US-2 CORRIDOR
AND WILL BE DOWN ALONG THE IA BORDER BY 00Z ACCORDING TO SREF
TIMING. THE ONLY TWO REAL CONCERNS WITH THIS FRONT ARE HOW WARM DOES
IT GET ACROSS SRN MN...FOLLOWED BY HOW QUICKLY DOES STRATUS MAKE ITS
RETURN IN ITS WAKE. ASSUMING STATUS DOES NOT FILL BACK IN TO THE
WEST/NORTH TONIGHT...SHOULD GET A GOOD PERIOD OF SUNSHINE INTO THE
AFTERNOON ACROSS THE SRN HALF OF THE AREA MONDAY...WITH HIGHS EASILY
PUSHING INTO THE LOW 40S GIVEN THE MILD START IN THE MID/UPPER 20S.
GIVEN FRONTAL TIMING...ALSO HAVE A NON-DIURNAL TEMPERATURE CURVE
BASED OFF OF THE SREF...WHICH HELD TEMPERATURES STEADY IN CAA ACROSS
THE NW CWA IN THE AFTERNOON. ASSUMING CLOUDS DO NOT MESS THINGS UP
TOMORROW...SHOULD HAVE A NICE GRADIENT IN HIGHS...WITH UPPER 20S UP
AROUND AXN AND MID 40S DOWN ALONG I-90.
FOR MONDAY NIGHT...MODELS ALL IN GOOD AGREEMENT ON STRATUS COMING
BACK IN BEHIND THE FRONT. WHERE DISAGREEMENTS COME ABOUT IS HOW
QUICKLY TO IMPROVE SKIES GOING INTO THE DAY ON TUESDAY. NAM
BASICALLY KEEPS THE ENTIRE AREA UNDER THE STRATUS THROUGH
WEDNESDAY...WHILE THE GFS/ECMWF WOULD SUGGEST SKIES WILL MOSTLY
CLEAR OUT BY 12Z WEDNESDAY. MODELS TEND TO BE TOO AGGRESSIVE WITH
CLEARING OUT OF CLOUDS...SO DID FAVOR THINGS TOWARD THE SLOWER NAM.
BESIDE THE CLOUDS...TEMPERATURES WILL BE NOTICEABLY COLDER
TUESDAY/WEDNESDAY AS H85 TEMPS TUMBLE DOWN TO AROUND -10C...WITH
HIGHS GETTING BACK DOWN TO A LITTLE BIT BELOW NORMAL FOR THE FIRST
TIME IN A COUPLE OF WEEKS.
BESIDE THE CLOUD COVER...THE NAM IN PARTICULAR IS SPITTING OUT SOME
LIGHT QPF MONDAY NIGHT...SO DID ADD SOME SCT FLURRY WORDING TO THE
FORECAST. LACK OF DEEP FORCING/MOISTURE SHOULD KEEP IT FROM GETTING
ANY WORSE THAN THAT.
NEXT REINFORCING SHOT OF COLD AIR WILL COME DOWN THURSDAY
NIGHT...BUT OUT AHEAD OF THIS FRONT...WILL HAVE A QUICK WARMUP FOR
THURSDAY AS A MILD WSW FLOW RETURNS. 1040 MB HIGH WILL SETTLE OVER
THE AREA FOR FRIDAY...WITH A QUICK RETREAT IN TEMPS EXPECTED FOR THE
END OF THE WEEK.
BIG DISAGREEMENTS BETWEEN THE GFS/ECMWF START SHOWING UP FOR NEXT
WEEKEND...WITH THE ECMWF STARTING TO BUILD A DEEP TROUGH OVER THE
ROCKY MOUNTAINS...WHILE THE GFS KEEPS SOME VESTIGE OF THE RIDGE
GOING ALONG THE WEST COAST. BY SATURDAY AFTERNOON...ECMWF HAS H85
TEMPS BACK UP AROUND +5C ACROSS WRN MN...WHEREAS THE GFS HAS THINGS
SIGNIFICANTLY COLDER...WITH H85 TEMPS AT THE SAME TIME DOWN AROUND
-10C. THE ECMWF IDEA WOULD HAVE HIGHS PUSHING 50 AGAIN OUT IN WRN MN
BY SUNDAY...WHILE THE GFS WOULD KEEP THINGS BACK DOWN AROUND 30.
WITH ALL OF THE UNCERTAINTY...STUCK CLOSE THE THE CENTRAL REGION
BLENDED GUIDANCE...WHICH BASICALLY TAKES THE MIDDLE ROAD FOR THE
WEEKEND.
&&
.AVIATION.../06Z TAF ISSUANCE/
PERSISTENT LOW CLDS/FG ACROSS THE EASTERN FA IS THE MAIN CONCERN
IS THE SHORT TERM AND WHETHER STRONGER SW FLOW IN THE BOUNDARY
LAYER DEVELOPING...WILL ALLOW FOR THE CLDS TO MOVE OUT DURING THE
NEXT 6 TO 12 HRS.
BASED ON CURRENT SATELLITE TRENDS OVER THE PAST FEW HRS...AND
BOUNDARY LAYER MOISTURE REMAINING HIGH...MSP/RNH/EAU WILL LIKELY
CONTINUE THE IFR/LIFR CIGS THRU 12Z...WITH A SLOW EROSION FROM THE
WEST/NW AS A COLD FRONT MOVES ACROSS THE AREA BY AFTN.
LATEST RUC HAS A GOOD HANDLE ON THE LOW LEVEL MOISTURE AND
ASSOCIATED CLDS...BUT IT CONTINUES TO DECREASE THE CLDS FROM THE
WEST TOO FAST THAN CURRENTLY INDICATED. WITH SOME UNCERTAINTY PAST
12Z...WILL HOLD ON TO LIFR/IFR CIGS AT RNH/EAU UNTIL WNDS SHIFT TO
THE W/NW BY NOON. RWF/AXN/STC WILL LIKELY SEE SOME BR/FG THIS
MORNING...BUT ENOUGH MIXING IN THE BOUNDARY LAYER SHOULD PRECLUDE
ANY SIGNIFICANT DENSE FG BY MORNING. CIGS ACROSS FAR SW MN MAY
AFFECT RWF BY 12Z...BUT WNDS ARE NOT CONDUCIVE FROM THE BOUNDARY
LAYER TO ADV THESE CLDS TO THE NE THIS MORNING. TIMING OF THE
COLD FRONT AND ASSOCIATED MVFR CIGS ARE CLOSE TO PREVIOUS TAFS.
THE ONSET OF MVFR CIGS MAY BE A BIT TOO FAST BASED ON UPSTREAM
CLDS. WNDS WILL BECOME W/WNW THIS DURING THE MORNING...THEN SHIFT
TO THE N/NNE AND INCREASE DURING THE AFTN/EVENING.
MSP...THRU 12Z...IFR CIGS AND VSBYS ARND 3-5SM WILL CONTINUE. BY
12Z...SOME UNCERTAINTY EXIST IF THE WESTERN EDGE OF THE CLDS WILL
MOVE FAR ENOUGH EAST TO BECOME SCT008 AT THE AIR FIELD.
THEREFORE...INCLUDED A TEMPORARY PERIOD OF POSSIBLE VFR BETWEEN
11-15Z. MVFR CIGS WILL ONCE AGAIN ADV BACK ACROSS THE REGION BY
AFTN AS A COLD FRONT MOVES SOUTHWARD. WNDS WILL BECOME MORE W/WNW
BY 12Z...THEN SHIFT TO THE NW AFT 18Z. WNDS SHOULD INCREASE IN SPD
BY 22-01Z...WITH A FEW GUSTS OVER 20 KTS POSSIBLE.
.TUE...MVFR CIGS EARLY WITH -SN POSSIBLE.
.WED...VFR.
..JLT..
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
MPG/JLT
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
308 AM CST MON FEB 6 2012
.DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE EXTENT OF STRATUS/FOG AND HOW MUCH THIS
CAN ERODE THROUGH THE DAY. FOCUS THEN SHIFTS TO INCOMING COLD
FRONT AND SMALL CHANCE OF PCPN TONIGHT INTO TUESDAY.
UPPER CLOSED LOW CURRENTLY OVER THE GREAT BASIN WILL OPEN AND
CONTINUE TO PUSH EAST TOWARD THE CENTRAL PLAINS TODAY WHILE A
SHORTWAVE TROF OVER SRN CANADA MOVES SOUTH INTO THE NRN PLAINS
TONIGHT. AT THE SFC...AREA OF HIGH PRESSURE IS CENTERED OVER THE
SOUTHERN PLAINS WITH CALM WINDS OVER THE ENTIRE CWA. DENSE FOG
FORMED EARLY LAST EVENING OVER SNOWPACK AND DO EXPECT FOG TO LIFT
BY MID-LATE MORNING. STRATUS DECK OVER THE EASTERN COUNTIES IS
EXPECTED TO HANG ON IN THRU MUCH OF THE MORNING AND PERHAPS EVEN
INTO THE AFTERNOON HOURS AS INDICATED BY LATEST HRRR MODEL RUNS.
WL EXTEND DENSE FOG ADVISORY UNTIL 16Z AS VISIBILITIES WL BE SLOW
TO IMPROVE. STRATUS IN ADDITION TO SNOWCOVER WL PLAY HAVOC ON
HIGH TEMPERATURES. HAVE FORECAST HIGHS NEAR OR JUST ABOVE
FREEZING TODAY.
CDFNT ASSOCIATED WITH SRN CANADIAN SHORTWAVE WL MOVE INTO THE REGION
EARLY THIS EVENING AS WEAKENING SHORTWAVE ENERGY FROM GREAT BASIN
LOW APPROACHES THE AREA. LIGHT PCPN STILL ON TRACK TO DEVELOP ACROSS
KS/MO AND INTO SERN NEB. FORECAST SOUNDINGS INDICATE THE POTENTIAL
FOR LIGHT FREEZING DRIZZLE INTITIALLY AND THEN A QUICK CHANGE TO
LIGHT SNOW IF NOT JUST FLURRIES. PERIOD OF FORCING IS BRIEF AND
ONLY EXPECT LIGHT SNOWFALL ACCUMULATIONS OF GENERALLY A TENTH OF
AN INCH OR SO LATE TONIGHT INTO TUESDAY MORNING.
DRY WEATHER IS EXPECTED THEREAFTER AS SFC HIGH PRESSURE MOVES
OVER THE REGION ON WEDNESDAY. A STRONG COLD FRONT WILL SURGE SOUTH
THROUGH THE AREA LATE THURSDAY. HAVE COOLED TEMPS SIGNIFICANTLY
OVER THE WEEKEND TO ACCOUNT FOR THIS SURGE OF COLD AIR.
KERN
&&
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
AS EXPECTED FOG HAS DEVELOPED AT ALL TAF SITES THIS EVNG. THESE LIFR
CONDS SHOULD CONT THROUGH A GOOD PART OF THE NIGHT AT ALL 3 SITES.
SOME IMPROVEMENT IN VISBY IS EXPECTED DURING THE MRNG BUT AT LNK/OMA
THE LIFR CIGS ARE LIKELY TO CONT THROUGH AT LEAST THE MRNG AND MAY
TRY TO CONT INTO THE AFTN. AT OFK THE LOW LEVEL FLOW FM THE WEST
WILL LIKELY ALLOW FOR THE LOW STUFF TO MOV OUT BY MID TO LATE MRNG
AS THEY ARE EXPECTED TO BE ON THE EDGE OF THE WWD EXTENT OF THE
CLOUDS. IF THE LOW CLOUDS DO EXIT OMA/LNK TMRW AFTN WE MAY ONCE
AGAIN SEE SOME FG DVLP MON EVNG AHEAD OF A COLD FRONT THAT WILL MOV
THRU LATE IN THE EVNG CLEANING OUT THE LOW LEVEL MOISTURE AND
TURNING THE WINDS TO THE N.
BOUSTEAD
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR NEZ012-015-
017-018-030>034-042>045-050>053-065>068-078-088>093.
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ043-055-
056-069-079-080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1141 PM CST SUN FEB 5 2012
.AVIATION...
06Z TAFS FOR KOFK...KOMA AND KLNK.
AS EXPECTED FOG HAS DEVELOPED AT ALL TAF SITES THIS EVNG. THESE LIFR
CONDS SHOULD CONT THROUGH A GOOD PART OF THE NIGHT AT ALL 3 SITES.
SOME IMPROVEMENT IN VISBY IS EXPECTED DURING THE MRNG BUT AT LNK/OMA
THE LIFR CIGS ARE LIKELY TO CONT THROUGH AT LEAST THE MRNG AND MAY
TRY TO CONT INTO THE AFTN. AT OFK THE LOW LEVEL FLOW FM THE WEST
WILL LIKELY ALLOW FOR THE LOW STUFF TO MOV OUT BY MID TO LATE MRNG
AS THEY ARE EXPECTED TO BE ON THE EDGE OF THE WWD EXTENT OF THE
CLOUDS. IF THE LOW CLOUDS DO EXIT OMA/LNK TMRW AFTN WE MAY ONCE
AGAIN SEE SOME FG DVLP MON EVNG AHEAD OF A COLD FRONT THAT WILL MOV
THRU LATE IN THE EVNG CLEANING OUT THE LOW LEVEL MOISTURE AND
TURNING THE WINDS TO THE N.
BOUSTEAD
&&
.UPDATE...
UPDATED TO ADD DENSE FOG ADVISORY.
&&
.DISCUSSION...
THE STRATUS DECK IS SLOWLY MAKING WWD PROGRESS ACROSS THE CTNRL
PART OF THE CWA. THE OPERATIONAL MODELS CONT TO STRUGGLE WITH THIS
NEAR GROUND LAYER DECK. ON THE WESTERN EDGE OF THIS DECK THE
TEMPERATURES FELL RAPIDLY THIS EVENING AND ALLOW FOR DENSE FOG TO
DVLP WITH ALL THE LOW LEVEL MOISTURE AROUND AND LIGHT WINDS. WOULD
EXPECT THE DECK TO CONT TO MAKE VERY SLOW PROGRESS TO THE WEST
OVERNIGHT...ESPECIALLY IN SE NEB WHERE THE WINDS JUST OFF THE SFC
ARE WEAKER THAN IN NE NEB. OTHERWISE THE DENSE FOG SHOULD BE
FAIRLY WIDESPREAD OVERNIGHT. LATE TONIGHT THE LOW LEVEL GRADIENT
STARTS TO INCREASE A LITTLE AND BY MON MRNG THIS SHOULD START TO
MOV THE STRATUS BACK EWD.
BOUSTEAD
&&
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
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 9 AM CST MONDAY FOR NEZ015-017-018-
030>034-042>045-050>053-065>068-078-088>093.
IA...DENSE FOG ADVISORY UNTIL 9 AM CST MONDAY FOR IAZ043-055-056-069-
079-080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
116 AM EST MON FEB 6 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE OVER THE GREAT LAKES WILL BUILD
SOUTHEAST ACROSS PENNSYLVANIA ON MONDAY. A SERIES OF SHORTWAVES
WILL CARVE OUT A DEEPENING TROUGH ACROSS THE EASTERN CONUS BY
MID TO LATE WEEK.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
CLEAR SKY AND A LIGHT WIND HAVE ALLOWED TEMPS TO FALL TO THE 20S
AS OF 06Z. AS SFC RIDGE DRIFTS SOUTH OF THE STATE...WIND MIGHT PICK UP A
BIT FROM THE WEST...CAUSING TEMPS TO LEVEL OFF DURING THE NEXT
COUPLE OF HOURS. BOTH LAMP GUIDANCE AND RUC SFC TEMPS INDICATE NO
MORE THAN A COUPLE DEG DROP IN TEMPS BTWN 06Z-12Z.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
INCREASING WLY TO SWRLY FLOW AHEAD OF AN APPROACHING COLD FRONT TO
THE NORTH 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.
PREFRONTAL AIR MASS WILL REMAIN UNSEASONABLY MILD MONDAY NIGHT...
BUT WITH SLIGHT DECOUPLING MINS SHOULD STILL DROP BELOW FREEZING
IN MOST LOCATIONS. EXPECT MINS TUESDAY MORNING TO RANGE FROM THE
MID 20S IN THE NORTH TO AROUND 30 IN THE SOUTH.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
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.
AT THE SAME TIME...A SERIES OF FAST MOVING SYSTEMS MAY BRING
LIGHT SNOW AND SOME LIGHT RAIN TO THE AREA TUE INTO EARLY THU.
NOT A LOT OF CHANGE FROM YESTERDAY.
ANOTHER COLD FRONT DROPS SE LATE IN THE WEEK...BUT EXPECT THE
REAL COLD AIR TO STAY OVER EASTERN CANADA. WENT WITH A DRY
WEEKEND FOR NOW...AS EXPECT THE FRONT TO BE NORTH OF CENTRAL
PA.
&&
.AVIATION /06Z MONDAY THROUGH FRIDAY/...
UPPER TROUGH IS MOVING
OFFSHORE AS WEAK FLOW DOMINATES THE REGION. DRY AIR ADVECTION WILL
ALLOW FOR VFR CIGS AND VSBYS ACROSS THE REGION. THE ONLY CHANCE
FOR MVFR CIGS WILL BE ALONG THE NY AND PA BORDER WITH A SLIGHT
POSSIBILITY ONCE THE REGION DECOUPLES AT BFD. ELSEWHERE VFR
CONDITIONS WILL DOMINATE THROUGH MONDAY.
OUTLOOK...
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS WITH
SHSN. THU...VFR. FRI...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...DEVOIR/MARTIN
NEAR TERM...DANGELO/FITZGERALD
SHORT TERM...DEVOIR
LONG TERM...MARTIN
AVIATION...CERU/RXR
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
327 AM CST MON FEB 6 2012
.DISCUSSION.../ISSUED AT 900 PM CST/
MAIN CHALLENGE IN THE NEAR TERM IS THE FOG THAT HAS DEVELOPED
ACROSS EASTERN SECTIONS OF THE FORECAST AREA. ISSUED DENSE FOG
ADVISORY EARLIER FOR NORTHWEST IOWA...AND HAVE EXPANDED THE ADVISORY
TWO ROWS OF COUNTIES TO THE NORTH WITH LOW LEVEL SOUTHWEST FLOW
DRIVING THE FOG. FOG WILL LIKELY RUN INTO TERRAIN IN SOUTHWEST
MINNESOTA...SO POTENTIAL FOR ADDITIONAL EXPANSION IS SOMEWHAT
LIMITED. EXPECT FOG TO ERODE ALONG THE WESTERN EDGE IN THE 16-17Z
TIMEFRAME IN SIMILAR FASHION TO YESTERDAY. FOG WILL HAVE AN EFFECT
ON DIURNAL TREND...AND HAVE SLOWED WARMING IN THE EAST COMPARED TO
MODEL TRENDS AND HAVE ALSO REDUCED HIGHS SLIGHTLY.
COLD FRONT IS EXPECTED TO DIVE INTO CWA LATE THIS AFTERNOON AND THIS
EVENING. LOW LEVEL COLD AIR ADVECTION WILL KEEP ATMOSPHERE
MIXED...BUT DRY AIR WILL REALLY LIMIT POTENTIAL FOR ANY
PRECIPITATION. DROPPED MENTION OF FLURRIES AFTER 06Z...BUT KEPT
MENTION IN FAR SOUTHERN EDGE OF CWA IN THE 12-18Z TIMEFRAME AS
SHALLOW CLOUD LAYER MAY DEVELOP AROUND 900 MB NEAR THE DENDRITIC
LAYER. AM NOT EXPECTING ANYTHING MORE THAN FLURRIES FROM SHALLOW
SATURATED LAYER.
EVEN THOUGH 925 HPA TEMPS ARE EXPECTED TO COOL TO AROUND -10 C BY
MID DAY TUESDAY...TEMPERATURES WILL ONLY BE SLIGHTLY BELOW NORMAL
DUE TO LACK OF SNOW COVER AND MODIFYING AIRMASS ACROSS THE AREA.
MILD AIR RETURNS TO THE REGION MID WEEK BEFORE ANOTHER ARCTIC PUSH
MOVES INTO THE REGION ON THURSDAY. LEFT GUIDANCE FORECAST AS
IS...WITH GUIDANCE VALUES HEDGING TOWARD THE WARM SIDE OF POSSIBLE
SOLUTIONS. RIP AG.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
STRATUS OVER NORTHWESTERN IOWA LATE THIS EVENING BEGINNING TO CREEP
SLOWLY BACK TO THE NORTH AS LOW LEVEL WINDS BECOMING SOUTHWESTERLY.
THIS WILL KEEP THAT AREA...INCLUDING KSUX WITH IFR/LIFR CEILINGS AND
MVFR/IFR VISIBILITIES THROUGH THE NIGHT. SOME UNCERTAINTY ON HOW FAR
NORTH STRATUS MAY PROGRESS OVERNIGHT WITH MODELS NOT HANDLING IT
WELL AT ALL...BUT MAY MAKE IT INTO THE KFSD AREA BY 06Z. FARTHER TO
THE NORTH...SKIES WILL REMAIN CLEAR OVERNIGHT...THOUGH THERE MAY BE
SOME LOCAL MVFR VISIBILITIES. A COLD FRONT WILL SWING THROUGH THE
REGION ON MONDAY...WITH STRATUS DISSIPATING WITH BETTER MIXING AHEAD
AND BEHIND THE FRONT. WINDS WILL PICK UP OUT OF THE NORTHWEST IN THE
LATER AFTERNOON BEHIND THE FRONT.
&&
.PREV 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.
&&
.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
1020 PM CST SUN FEB 5 2012
.DISCUSSION.../ISSUED AT 900 PM CST/
TRICKY FORECAST TONIGHT CONCERNING LOW TEMPERATURES. STRATUS IN NW
IA IS BEGINNING TO OOZE BACK NORTHWARD AS WINDS JUST OFF THE SURFACE
SHIFT TO THE SSW. IT APPEARS AT THE MOMENT...THAT AN APPROXIMATE
LINE FROM YANKTON...TO SIOUX FALLS/DELL RAPIDS...TO EVENTUALLY
WINDOM MN WILL BE ON THE EDGE OF THE STRATUS. THEREFORE LOW
TEMPERATURES IN THAT CORRIDOR WILL BE GREATLY INFLUENCED UP OR DOWN
BY THE CLOUDS. FOR NOW...LOWERED THE MIN TEMPERATURES AT SIOUX FALLS
AND YANKTON A LITTLE BIT...SINCE CURRENT READINGS ARE ALREADY NEAR
LOWS. ALSO LOWERED READINGS AT BROOKINGS AND HURON WHO COMMONLY
RADIATE OUT EVEN WITH A LIGHT SOUTH WIND. RAISED TEMPERATURES A TAD
IN NW IA DEEP INTO THE STRATUS...AS THAT AREA HAS NO CHANCE OF
CLEARING OUT. OTHERWISE...THE AREAS OF FOG WE HAVE GOING STILL LOOKS
VERY GOOD FOR THE AREA COVERED...PROJECTING THE STRATUS NORTHWARD.
&&
.AVIATION.../FOR THE 06Z TAF ISSUANCE/
STRATUS OVER NORTHWESTERN IOWA LATE THIS EVENING BEGINNING TO CREEP
SLOWLY BACK TO THE NORTH AS LOW LEVEL WINDS BECOMING SOUTHWESTERLY.
THIS WILL KEEP THAT AREA...INCLUDING KSUX WITH IFR/LIFR CEILINGS AND
MVFR/IFR VISIBILITIES THROUGH THE NIGHT. SOME UNCERTAINTY ON HOW FAR
NORTH STRATUS MAY PROGRESS OVERNIGHT WITH MODELS NOT HANDLING IT
WELL AT ALL...BUT MAY MAKE IT INTO THE KFSD AREA BY 06Z. FARTHER TO
THE NORTH...SKIES WILL REMAIN CLEAR OVERNIGHT...THOUGH THERE MAY BE
SOME LOCAL MVFR VISIBILITIES. A COLD FRONT WILL SWING THROUGH THE
REGION ON MONDAY...WITH STRATUS DISSIPATING WITH BETTER MIXING AHEAD
AND BEHIND THE FRONT. WINDS WILL PICK UP OUT OF THE NORTHWEST IN THE
LATER AFTERNOON BEHIND THE FRONT.
&&
.PREV 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.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
257 AM CST MON FEB 6 2012
.SHORT TERM...TODAY THROUGH THURSDAY
257 AM CST MON FEB 6 2012
ONCE AGAIN WE ARE LEFT WITH A STRATUS DECK TO CONTEND WITH TODAY
WHICH WILL LIKELY HOLD TEMPERATURES BACK A BIT BEFORE A COLD FRONT
COMES THROUGH LATE THIS AFTERNOON AND EVENING.
A CUT OFF MID LEVEL LOW CONTINUES TO SPIN ACROSS THE CENTRAL
ROCKIES AS THE POLAR VORTEX BEGINS ITS DESCENT THROUGH EASTERN
CANADA. AT THE SURFACE...A RIDGE OF HIGH PRESSURE HAS DROPPED TO
THE SOUTHERN PLAINS WHILE A COLD FRONT IS PUSHING SOUTH ACROSS
ONTARIO AND THE DAKOTAS. MEANWHILE...A LOAN CLUSTER OF STRATUS
REMAINS TRAPPED UNDER AN INVERSION AROUND 950MB AND COVERS ALL OF
IOWA...THE WESTERN TWO THIRDS OF WISCONSIN AND THE EASTERN THIRD
OF MINNESOTA. THE 06.00Z MPX RAOB SHOWS THAT THIS LAYER OF STRATUS
IS ABOUT 200FT THICK...WHICH SHOULD BE THIN ENOUGH FOR SOME EXTRA
WIND TURBULENCE AND WARMING SURFACE TEMPERATURES TO POKE SOME
HOLES IN IT. THIS HAS NOT BEEN THE CASE OVERNIGHT DESPITE THE
INCREASING SURFACE WINDS AS THE STRATUS REMAINS A UNIFIED LAYER.
AS HAS BEEN THE CASE NOW FOR THE PAST 4 DAYS AND WHAT SEEMS THE
REST OF THIS WINTER...THE FORECAST FOR TODAY RESTS SOLELY ON WHAT
THIS THIN LAYER OF STRATUS DECIDES TO DO. IF THE STRATUS LINGERS
THROUGH THE DAY...HIGH TEMPERATURES WILL REMAIN IN THE LOW TO MID
30S. HOWEVER...IF SKIES CLEAR OUT AND BECOME SUNNY...HIGHS WILL
LIKELY REACH THE MID 40S. THE 06.00Z TO 06.05Z HRRR CEILING
PROJECTIONS HAVE ALL HAD A PRETTY GOOD HANDLE ON THE CURRENT
STRATUS FIELD AND HAVE BEEN FAIRLY CONSISTENT WITH ITS FORECAST OF
KEEPING THE STRATUS IN TACT THROUGH THE MORNING AND EARLY
AFTERNOON. THE 06.05Z HRRR RUN DID SHOW SOME HOLES STARTING TO POP
UP IN THE EARLY AFTERNOON...WHICH SEEMS PLAUSIBLE GIVEN THE
SHALLOW CLOUD DEPTH AND BETTER MIXING DUE TO AN INCREASING LOW
LEVEL PRESSURE GRADIENT AND WINDS. THEREFORE...HAVE KEPT
TEMPERATURES DOWN THROUGH THE MORNING WITH THE CLOUD COVER
EXPECTED TO AT LEAST HOLD ON UNTIL LUNCHTIME WITH A QUICK JUMP IN
TEMPERATURES THIS AFTERNOON AS HOLES START TO DEVELOP. WOULD NOT
BE SURPRISED TO SEE A FEW HIGHER TEMPERATURES CROP UP THIS
AFTERNOON...BUT CONFIDENCE IS JUST NOT HIGH ENOUGH AT THIS POINT
TO HAVE MID TO UPPER 40S IN THE FORECAST.
THE COLD FRONT ALONG THE US/CANADIAN BORDER THEN WILL ENTER THE
NORTHERN PORTION OF THE FORECAST AREA LATE THIS AFTERNOON AND PASS
THROUGH THE SOUTHERN PORTION OF THE FORECAST AREA BY MIDNIGHT
TONIGHT. SOME POST-FRONTAL FLURRIES LOOK POSSIBLE AS THE
TEMPERATURES IN THE LOW LEVEL CLOUD LAYER DROP TOWARD -10C
TONIGHT. THE 06.00Z NAM/GFS/GEM ALL HAVE SOME SPOTTY QPF THAT
SHOWS UP TONIGHT WHICH IS LIKELY A RESULT OF A SLIGHTLY DEEPER
DENDRITIC GROWTH ZONE THAT TRIES TO DEVELOP BETWEEN 900-750MB. THE
ONLY FORCING WITH THIS SYSTEM IS WITH SOME WEAKLY SLOPED
FRONTOGENESIS WITH THE MID LEVEL TROUGH LAGGING FAR BEHIND.
THUS...AM NOT TOO HIGH ON THE CHANCES FOR GETTING AN ACCUMULATING
SNOW OUT OF THIS FEATURE.
BEYOND THIS IT WILL JUST BE A QUESTION OF WHEN SKIES CLEAR OUT AS
A RIDGE OF HIGH PRESSURE SETS UP ACROSS THE PLAINS AND GREAT
LAKES. THIS RIDGE WILL DROP TEMPERATURES DOWN TO SEASONAL LEVELS GOING
INTO MID WEEK WITH THE CLEARING LIKELY TAKING PLACE ON WEDNESDAY.
.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
257 AM CST MON FEB 6 2012
THE MAIN FOCUS IN THE LONG TERM CONTINUES TO BE WITH WHEN A COLD
FRONT WILL DROP DOWN AND HOW COLD WILL IT GET LATE IN THE WEEK
AND WEEKEND. IT APPEARS THAT THE 06.00Z GFS AND ECMWF HAVE
FINALLY COME TO A COMPROMISE WITH BRINGING A NORTHEAST TO
SOUTHWEST ORIENTATED COLD FRONT THROUGH THE REGION THURSDAY
AFTERNOON AND EVENING WITH NO PRECIPITATION OCCURRING IN THE
REGION. TEMPERATURES WILL COOL TO BELOW NORMAL WITH 850MB
TEMPERATURES DROPPING TO -20C FOR A PERIOD THURSDAY NIGHT INTO AT
LEAST FRIDAY. THE 06.00Z ECMWF IS A BIT FASTER WITH BRINGING
WARMER AIR BACK IN AT THE LOW LEVELS ON SATURDAY ALREADY WHILE THE
06.00Z GFS HOLDS ONTO THE COLDER AIR FOR LONGER. THUS...HAVE GONE
WITH THE COLDER TEMPERATURES THURSDAY THROUGH SATURDAY WITH A
WARMING TREND SUNDAY.
&&
.AVIATION...THROUGH 06Z TUESDAY
1135 PM CST SUN FEB 5 2012
AT 05Z A LARGE AREA OF STRATUS WAS OVER THE UPPER MISSISSIPPI
RIVER VALLEY REGION. THE BACK EDGE WAS PUSHING INTO SOUTH CENTRAL
MINNESOTA. HOWEVER...MORE STRATUS WAS LIFTING NORTHWARD OUT OF
IOWA INTO SOUTHWEST MINNESOTA. MODELS HAVE STRUGGLED OVER THE PAST
FEW DAYS WITH THE TREND TO CLEAR IT OUT TOO QUICKLY DURING THE DAY
AND THE 06.00Z NAM AGAIN DOING THE SAME THING. 06.02Z HRRR SHOWING
STRATUS TO REMAIN IN PLACE THROUGH AT LEAST 18Z AND THIS GOING
WITH A MORE PESSIMISTIC FORECAST. CAN NOT RULE OUT SOME BRIEF
CLEARING AFTER 18Z-20Z MONDAY...BUT IT WILL BE SHORT LIVED AS A
COLD FRONT WILL DROP SOUTHWARD THROUGH THE AREA...WITH ALL THE
MODELS SHOWING POST FRONTAL STRATUS TO MOVE BACK IN AROUND 00Z.
THUS WILL KEEP THE IFR CONDITIONS GOING THROUGH MUCH OF THE DAY
WITH A BRIEF BREAK THIS AFTERNOON BEFORE MVFR POST FRONTAL
CEILINGS MOVE IN.
NEXT QUESTION IS ON ANY POST FRONTAL PRECIPITATION CHANCES. 06.00Z
NAM AND GFS BOTH SHOWING SOME LIGHT PRECIPITATION. NAM IS THE
EARLIEST IN THE EVENING...WHILE THE GFS WOULD SUGGEST AFTER
MIDNIGHT. ONE CONCERN OF ANYTHING FALLING IN THE EVENING...IS THE
POTENTIAL LACK OF ICE CRYSTALS IN THE CLOUDS WHICH COULD RESULT IN
SOME PATCHY FREEZING DRIZZLE RATHER THAN FLURRIES. FOR NOW WILL
JUST MENTION FLURRIES...BUT THIS WILL HAVE TO BE MONITORED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
257 AM CST MON FEB 6 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1135 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 06Z TUESDAY
1135 PM CST SUN FEB 5 2012
AT 05Z A LARGE AREA OF STRATUS WAS OVER THE UPPER MISSISSIPPI
RIVER VALLEY REGION. THE BACK EDGE WAS PUSHING INTO SOUTH CENTRAL
MINNESOTA. HOWEVER...MORE STRATUS WAS LIFTING NORTHWARD OUT OF
IOWA INTO SOUTHWEST MINNESOTA. MODELS HAVE STRUGGLED OVER THE PAST
FEW DAYS WITH THE TREND TO CLEAR IT OUT TOO QUICKLY DURING THE DAY
AND THE 06.00Z NAM AGAIN DOING THE SAME THING. 06.02Z HRRR SHOWING
STRATUS TO REMAIN IN PLACE THROUGH AT LEAST 18Z AND THIS GOING
WITH A MORE PESSIMISTIC FORECAST. CAN NOT RULE OUT SOME BRIEF
CLEARING AFTER 18Z-20Z MONDAY...BUT IT WILL BE SHORT LIVED AS A
COLD FRONT WILL DROP SOUTHWARD THROUGH THE AREA...WITH ALL THE
MODELS SHOWING POST FRONTAL STRATUS TO MOVE BACK IN AROUND 00Z.
THUS WILL KEEP THE IFR CONDITIONS GOING THROUGH MUCH OF THE DAY
WITH A BRIEF BREAK THIS AFTERNOON BEFORE MVFR POST FRONTAL
CEILINGS MOVE IN.
NEXT QUESTION IS ON ANY POST FRONTAL PRECIPITATION CHANCES. 06.00Z
NAM AND GFS BOTH SHOWING SOME LIGHT PRECIPITATION. NAM IS THE
EARLIEST IN THE EVENING...WHILE THE GFS WOULD SUGGEST AFTER
MIDNIGHT. ONE CONCERN OF ANYTHING FALLING IN THE EVENING...IS THE
POTENTIAL LACK OF ICE CRYSTALS IN THE CLOUDS WHICH COULD RESULT IN
SOME PATCHY FREEZING DRIZZLE RATHER THAN FLURRIES. FOR NOW WILL
JUST MENTION FLURRIES...BUT THIS WILL HAVE TO BE MONITORED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
340 PM CST SUN FEB 5 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...BOYNE
LONG TERM...BOYNE
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LINCOLN IL
520 AM CST MON FEB 6 2012
.DISCUSSION...
ISSUED 235 AM CST MON FEB 6 2012
SHORT TERM...TODAY THROUGH WEDNESDAY...
MAIN HEADACHES THE LAST FEW HOURS HAVE BEEN WITH LOW CLOUDS AND
DENSE FREEZING FOG DEVELOPMENT. STRATUS DECK HAS BEEN ADVANCING
SOUTHEASTWARD AND HAD REACHED THE I-55 CORRIDOR AT 2 AM.
VISIBILITIES ALONG THIS EDGE QUICKLY TANKED AND THE 1/4 MILE
VISIBILITY EXTENDS NORTHWEST FOR ABOUT 60 MILES FROM THE LEADING
EDGE. HAVE ALSO BEEN SEEING SOME PATCHIER DENSE FOG DEVELOPING
OVER THE EASTERN CWA...IN AREAS WHERE SKIES HAVE BEEN MAINLY
CLEAR. MODEL GUIDANCE WITH THIS STRATUS DECK OVER THE LAST DAY OR
TWO HAS BEEN QUITE POOR. THE HRRR APPEARS TO DO THE BEST JOB...BUT
ONLY GOES OUT ABOUT 12 HOURS. THE LATEST RAPID-REFRESH ALSO SEEMS
TO BE OK...AND SPREADS THE CLOUDS OVER MOST OF THE REMAINING CWA
EARLY THIS MORNING AND KEEPS LOWER VISIBILITIES GOING THROUGH
ABOUT 9-10 AM...WITH FOG LIFTING FROM THE NORTHWEST. WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FOR AREAS BETWEEN THE ILLINOIS
RIVER AND I-70 FOR THIS MORNING. TEMPERATURES TODAY WILL BE VERY
TRICKY DEPENDING ON HOW FAST THE CLOUDS FINALLY BREAK UP THIS
AFTERNOON...IF THEY INDEED DO SO. HAVE UNDERCUT GUIDANCE
TEMPERATURES UNDERNEATH BY A FEW DEGREES UNDERNEATH THE STRATUS
DECK...BUT ANY BREAKUP TOO EARLY IN THE DAY WILL CAUSE SIGNIFICANT
ERRORS IN THE HIGH TEMPERATURE FORECAST.
THE OTHER FOCUS DURING THIS PERIOD WILL BE AS A SHORTWAVE...THE
REMNANTS OF A CUTOFF LOW CURRENTLY OVER THE CENTRAL ROCKIES...
INTERACTS WITH ANOTHER WAVE WHICH WILL SWEEP ACROSS THE GREAT
LAKES ON TUESDAY AND WEDNESDAY. STILL NOT A LOT OF MOISTURE
AVAILABILITY WITH THIS SYSTEM...WITH MOST OF THE MODEL GUIDANCE
SUPPORTING LOW CHANCE POPS ACROSS THE SOUTHERN HALF OF THE CWA.
MAY SEE SOME MINOR SNOW ACCUMULATIONS TUESDAY EVENING NEAR THE
I-72 CORRIDOR...DEPENDING ON HOW FAST SURFACE TEMPERATURES DROP
BEFORE THE PRECIPITATION EXITS.
LONG TERM...THURSDAY THROUGH SUNDAY...
MAIN FOCUS IN THIS PERIOD REMAINS WITH ARCTIC AIR MASS WHICH WILL
DROP INTO THE GREAT LAKES LATE IN THE WEEK. COLD FRONT PROGGED TO
MOVE ACROSS THE AREA EARLY FRIDAY MORNING...ALTHOUGH MOST OF THE
MOISTURE WILL BE CLOSER TO THE GREAT LAKES AND WILL GO WITH A DRY
FRONTAL PASSAGE HERE. HOWEVER...LATEST GFS/ECMWF BOTH BRING 850
MB TEMPERATURES AS LOW AS -17C INTO THE CWA BY SATURDAY MORNING...
WHICH WOULD KEEP MUCH OF THE CWA AT OR BELOW FREEZING ON
SATURDAY. AS WITH MOST OF THE COLD PERIODS THIS WINTER...ONLY
LOOKING AT ABOUT A 36-48 HOUR PERIOD WHERE IT WOULD ACTUALLY BE
CONSIDERED TO BE COLD...BEFORE TEMPERATURES QUICKLY RETURN TO NEAR
NORMAL.
GEELHART
&&
.AVIATION...
ISSUED 515 AM CST MON FEB 6 2012
DURATION OF VLIFR/LIFR CIGS AND VSBYS TODAY THE MAIN FORECAST
CHALLENGE. THE LOW STRATUS DECK THAT WAS OUT TO OUR NORTHWEST
STARTED TO INCREASE ITS SE MOVEMENT LAST EVENING AND HAS PUSHED
TO JUST NORTH OF THE I-70 CORRIDOR...AND EXTENDS WEST THRU THE
NORTHERN HALF OF MO INTO EXTREME EASTERN NEBRASKA. NOT MUCH
HOPE OF SEEING ANY SIGNIFICANT CLEARING TAKING PLACE TODAY
DESPITE BOUNDARY LAYER WINDS INCREASING OUT OF THE WEST AND
SOUTHWEST. WILL TAKE A MORE PESSIMISTIC OUTLOOK WTIH RESPECT
TO THE CIGS AND VSBYS TODAY AND CONTINUE TO KEEP AT LEAST IFR
CIGS/VSBYS INTO THIS AFTERNOON. THE BIG QUESTION IS HOW QUICKLY
THAT WILL TRANSITION FROM VLIFR TO IFR. BASED ON THE HI-RES
RAPID REFRESH SOLUTION...WILL START TO SEE A GRADUAL IMPROVEMENT
IN CIGS AND VSBYS AFTR 16Z BUT CONTINUE WITH IFR/LIFR CIGS DURING
THE AFTN. REALLY DON`T SEE ANY MECHANISM TO DISPERSE THE CLOUDS
AND IMPROVE THE CIGS SIGNIFICANTLY UNTIL A COLD FRONT MOVES ACRS
THE AREA LATER TONIGHT OR EARLY TUESDAY MORNING.
SURFACE WINDS WILL TEND TO BACK MORE INTO A SOUTHWEST DIRECTION
TODAY AT 8 TO 13 KTS...AND VEER MORE INTO THE WEST AND THEN
NORTHWEST LATE IN THE FORECAST PERIOD AS THE COLD FRONT
APPROACHES.
SMITH
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR ILZ031-037-038-
041>057-061.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
928 AM EST MON FEB 6 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WILL KEEP DRY MILD WEATHER ACROSS CENTRAL INDIANA
THROUGH TUESDAY. A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL
BRING THE CHANCE FOR LIGHT PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER FOR LATE
WEEK AND INTO THE WEEKEND. THE EXPANSION OF A BROAD UPPER LEVEL
TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
6 AM UPDATE...OBS AND WEBCAMS ACROSS THE NORTHERN WABASH VALLEY
SUGGEST THAT FREEZING FOG HAS BECOME MORE WIDESPREAD. HAVE GONE
AHEAD AND INTRODUCED A FREEZING FOG ADVISORY THROUGH 16Z FOR FAR
NORTHWEST FORECAST AREA. ARRIVAL OF BROAD STRATOCU DECK TO THE WEST
MAY SERVE TO MAINTAIN DENSE FOG INTO LATE MORNING.
EARLY MORNING DISCUSSION FOLLOWS.
CLEAR SKIES OVER A MAJORITY OF THE FORECAST AREA THIS MORNING. ONLY
EXCEPTION IS OVER NORTHERN WABASH VALLEY WHERE SHALLOW FREEZING FOG
AND POCKETS OF LOW STRATUS HAVE FORMED EARLY THIS MORNING. TEMPS AT
08Z WERE BELOW FREEZING...FROM THE MID 20S TO LOWER 30S.
MAIN FORECAST ISSUE FOCUSES ON FREEZING FOG THROUGH MID MORNING AND
POTENTIAL IMPACTS FROM DEVELOPING POCKETS OF STRATUS. BROAD AREA OF
STRATUS WITH CEILINGS AT OR BELOW 500FT CONTINUES TO EXPAND SLOWLY
EAST ACROSS NORTHERN ILLINOIS. MOST OF THE SHORT RANGE MODEL
GUIDANCE IS STRUGGLING MIGHTILY WITH THE LOCATION AND EXPANSION OF
THE LARGER STRATUS DECK OVER ILLINOIS...WITH ONLY THE RUC AND TO A
LESSER EXTENT THE 06Z NAM HINTING AT ITS PRESENCE CURRENTLY. HAVE
INTRODUCED AN SPS FOR FREEZING FOG OVER THE ENTIRE FORECAST AREA
THROUGH MID MORNING WITH THE MAIN CONCERN OVER NORTHWEST COUNTIES
AND THE NORTHERN WABASH VALLEY WHERE MANY LOCATIONS ALREADY
REPORTING BELOW 1SM. AT THIS POINT APPEARS DENSE FOG IN NORTHWEST
COUNTIES REMAINS PATCHY BUT SHOULD IT BECOME MORE WIDESPREAD...MAY
NEED TO CONSIDER A FREEZING FOG ADVISORY. WILL CONTINUE TO MONITOR
TRENDS CLOSELY OVER THE NEXT FEW HOURS. SPS SHOULD REMAIN SUFFICIENT
OVER THE REST OF THE FORECAST AREA AS FOG LIKELY TO REMAIN PATCHY.
ONCE VISIBILITIES IMPROVE LATER THIS MORNING...REMAINDER OF THE DAY
SHOULD BE FAIRLY QUIET WITH HIGH PRESSURE ACROSS THE REGION. ONE BIG
CAVEAT WILL BE THE LOCATION AND EXTENT OF THE STRATUS DECK AND JUST
HOW QUICKLY THAT MIXES OUT. AT THIS POINT...APPEARS THE DECK WILL
SPREAD ACROSS FAR NORTHWEST PORTIONS OF THE FORECAST AREA LATER THIS
MORNING. HOWEVER...UNCERTAINTY IS VERY HIGH WITH RESPECT TO HOW MUCH
FURTHER SOUTHEAST THE DECK MAY EXPAND INTO THE FORECAST AREA. HAVE
CHOSEN TO CARRY MOSTLY CLOUDY SKIES OVER NORTHWEST COUNTIES WITH
MOSTLY SUNNY/PARTLY CLOUDY CONDITIONS ELSEWHERE. ADJUSTMENTS WILL BE
MADE ACCORDINGLY THROUGH THE MORNING AS NEEDED.
TEMPS...VERY TRICKY FORECAST AS STRATUS DECK WILL PLAY A MAJOR
FACTOR. HAVE LOWERED TEMPS BY 3-5 DEGREES FROM PREVIOUS FORECAST
OVER THE NORTHERN WABASH VALLEY WHERE CONFIDENCE IS HIGHEST WITH
RESPECT TO CLOUD IMPACTS. SHOULD THE DECK HANG FOR LONGER...THESE
FORECAST HIGHS IN THE LOWER 40S ARE LIKELY TO BE TOO WARM. PLACED
TEMPS NEAR MOS GUIDANCE IN THE MID AND UPPER 40S ELSEWHERE.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AND
WEDNESDAY AS A SERIES OF WEAK UPPER LEVEL DISTURBANCES PASS THROUGH
THE LOWER GREAT LAKES.
HIGH PRESSURE RIDGE WILL BRING ANOTHER TRANQUIL NIGHT WITH CLEAR
SKIES TONIGHT. THE RIDGE SHIFTS EAST TUESDAY WITH MID AND HIGH LEVEL
CLOUDS EXPANDING INTO THE REGION FROM THE NORTHWEST. CHANCES FOR
PRECIPITATION ARE LIKELY TO HOLD OFF UNTIL TUESDAY EVENING AS LEAD
SHORTWAVE ASSOCIATED WITHIN LARGER UPPER TROUGH ROTATES ACROSS THE
REGION. ISENTROPIC LIFT AND OVERALL FORCING REMAIN GENERALLY
WEAK...BUT DOES APPEAR ENOUGH MOISTURE PRESENT FOR LIGHT
PRECIPITATION. WHILE A LIGHT RAIN/SNOW MIX IS POSSIBLE OVER SOUTHERN
COUNTIES TUESDAY EVENING...LOW LEVEL THERMALS AND MODEL SOUNDINGS
SHOW PRECIPITATION AS ALL SNOW AFTER MIDNIGHT AS THE BOUNDARY LAYER
AND NEAR SURFACE TEMPS COOL. SHORTWAVE AXIS SWINGS ACROSS THE
FORECAST AREA BETWEEN 06-12Z WEDNESDAY WITH BEST FORCING ALOFT. THIS
LIKELY TO BE THE TIMEFRAME WHEN LIGHT SNOW IS MOST PREVALENT WITH
HIGHEST POPS. APPEARS THERE COULD BE A FEW TENTHS OF AN INCH
ACCUMULATION BY DAYBREAK WEDNESDAY.
SCATTERED LIGHT SNOW SHOWERS WILL PERSIST WEDNESDAY MORNING WITH A
GRADUAL DIMINISHING OF COVERAGE AS BETTER MOISTURE AND FORCING SHIFT
EAST THROUGH THE DAY. CLOUDS AND A FEW FLURRIES LIKELY TO LINGER
UNTIL THE MAIN UPPER TROUGH PASSES WEDNESDAY AFTERNOON. WILL HOLD
ONTO LOW CHANCE POPS ON WEDNESDAY WITH MODEL SOUNDINGS FAVORING ANY
PRECIP TO FALL IN THE FORM OF LIGHT SNOW. NOT ANTICIPATING ANY
ADDITIONAL LIGHT ACCUMS AT THIS POINT. UPPER TROUGH MOVES AWAY TO
THE EAST WEDNESDAY WITH ANOTHER SURGE OF DEEP SUBSIDENCE ADVECTING
INTO THE REGION AS HIGH PRESSURE REESTABLISHES. SKIES SHOULD CLEAR
QUICKLY SETTING THE STAGE FOR A CHILLY NIGHT.
TEMPS...GENERALLY LEANED TOWARDS COOLER METMOS GUIDANCE THROUGH THE
PERIOD...ESPECIALLY TUESDAY NIGHT AND WEDNESDAY WITH CLOUDS AND
PRECIP. COLDEST NIGHT WILL BE WEDNESDAY NIGHT AS LOWS FALL TO NEAR
20 DEGREES UNDER CLEAR SKIES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
QUIET EXTENDED PERIOD FOR THE MOST PART...WITH THE ONLY EXCEPTION
BEING A VERY BROAD UPPER LEVEL TROUGH OVER MUCH OF THE GREAT LAKES
REGION AND MIDWEST ON FRIDAY/FRIDAY NIGHT. LATEST GFS AND EURO
MODEL RUNS ARE SHOWING MORE MOISTURE WITH AN ASSOCIATED COLD
FRONT...BUT INITIALIZATION NUMBERS ARE STILL TRENDING TOWARD A DRY
FRONTAL PASSAGE ON FRIDAY AFTERNOON/EVENING. AT THIS TIME...WILL
NOT MAKE ADJUSTMENTS TO INITIALIZATION NUMBERS UNTIL AFTER A FEW
MORE MODEL RUNS COME IN. OVERNIGHT LOWS WILL BE MORE REPRESENTATIVE
FOR THIS TIME OF YEAR WITH READINGS IN THE UPPER TEENS AND 20S DUE
TO THE CLEAR SKIES. THE AFOREMENTIONED COLD FRONT WILL LOWER
DAYTIME HIGHS A TAD ON SATURDAY...BUT THEY WILL QUICKLY INCREASE
BACK INTO THE UPPER 30S/LOW 40S BY SUNDAY AND MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 06/15Z KIND TAF UPDATE/...
EASTERN EDGE OF STRATUS/FOG DECK WAS NEAR A KHUF TO KOKOMO LINE. IT
PROBABLY WON`T GET MUCH FARTHER EAST BEFORE IT STARTS ERODING AND IT
WILL DEFINITELY STAY WEST OF KIND. VISIBILITIES OF 5 TO 6 MILES MAY
STAY AT KIND FOR ANOTHER HOUR. AFTER THAT MOSTLY CLEAR WITH NO
FLIGHT RESTRICTIONS. PREVIOUS AVIATION DISCUSSION FOLLOWS BELOW...
FLYING CONDITIONS VERY SIMILAR TO YESTERDAY MORNING. FOG WILL BE
PROBLEMATIC...ESPECIALLY AT KLAF AND KHUF THROUGH MID MORNING.
PLUS...CURRENT SATELLITE IS SHOWING LOW STRATUS DECK MOVING IN FROM
NORTHERN ILLINOIS RAISING CONCERN OVER POSSIBLE TRAPPING OF DENSE
FOG AT AFOREMENTIONED TAF SITES. SO...WILL KEEP TEMPO OF VLIFR
CONDITIONS AT KLAF AND KHUF THROUGH MID MORNING.
ELSEWHERE...CONDITIONS HAVE BEEN BEHAVING AT KIND AND KBMG WITH
VFR CATEGORY UP TO THIS POINT. AT WORST...COULD SEE SOME BRIEF MVFR
CONDITIONS OVER THE NEXT FEW HOURS AT THESE TAF SITES.
BEYOND MID MORNING...VFR CONDITIONS WILL PREVAIL FOR REMAINDER OF
TAF PERIOD. HIGH CLOUDS WILL INCREASE AT TAIL END OF TAF PERIOD AS
THE NEXT DISTURBANCE APPROACHES AREA...BUT THIS WILL HAVE NO
IMPACT ON FLIGHT OPERATIONS.
WINDS WILL BE WESTERLY AT 4 TO 8 KTS FOR THE MAJORITY OF TAF
PERIOD...AND WILL THEN START VEERING TO THE NORTHWEST TOMORROW
MORNING. SUSTAINED WIND SPEEDS WILL INCREASE TO 5 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028-029-035-043.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD/JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
647 AM EST MON FEB 6 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW
&&
.SYNOPSIS...
HIGH PRESSURE WILL KEEP DRY MILD WEATHER ACROSS CENTRAL INDIANA
THROUGH TUESDAY. A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL
BRING THE CHANCE FOR LIGHT PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER FOR LATE
WEEK AND INTO THE WEEKEND. THE EXPANSION OF A BROAD UPPER LEVEL
TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
6 AM UPDATE...OBS AND WEBCAMS ACROSS THE NORTHERN WABASH VALLEY
SUGGEST THAT FREEZING FOG HAS BECOME MORE WIDESPREAD. HAVE GONE
AHEAD AND INTRODUCED A FREEZING FOG ADVISORY THROUGH 16Z FOR FAR
NORTHWEST FORECAST AREA. ARRIVAL OF BROAD STRATOCU DECK TO THE WEST
MAY SERVE TO MAINTAIN DENSE FOG INTO LATE MORNING.
EARLY MORNING DISCUSSION FOLLOWS.
CLEAR SKIES OVER A MAJORITY OF THE FORECAST AREA THIS MORNING. ONLY
EXCEPTION IS OVER NORTHERN WABASH VALLEY WHERE SHALLOW FREEZING FOG
AND POCKETS OF LOW STRATUS HAVE FORMED EARLY THIS MORNING. TEMPS AT
08Z WERE BELOW FREEZING...FROM THE MID 20S TO LOWER 30S.
MAIN FORECAST ISSUE FOCUSES ON FREEZING FOG THROUGH MID MORNING AND
POTENTIAL IMPACTS FROM DEVELOPING POCKETS OF STRATUS. BROAD AREA OF
STRATUS WITH CEILINGS AT OR BELOW 500FT CONTINUES TO EXPAND SLOWLY
EAST ACROSS NORTHERN ILLINOIS. MOST OF THE SHORT RANGE MODEL
GUIDANCE IS STRUGGLING MIGHTILY WITH THE LOCATION AND EXPANSION OF
THE LARGER STRATUS DECK OVER ILLINOIS...WITH ONLY THE RUC AND TO A
LESSER EXTENT THE 06Z NAM HINTING AT ITS PRESENCE CURRENTLY. HAVE
INTRODUCED AN SPS FOR FREEZING FOG OVER THE ENTIRE FORECAST AREA
THROUGH MID MORNING WITH THE MAIN CONCERN OVER NORTHWEST COUNTIES
AND THE NORTHERN WABASH VALLEY WHERE MANY LOCATIONS ALREADY
REPORTING BELOW 1SM. AT THIS POINT APPEARS DENSE FOG IN NORTHWEST
COUNTIES REMAINS PATCHY BUT SHOULD IT BECOME MORE WIDESPREAD...MAY
NEED TO CONSIDER A FREEZING FOG ADVISORY. WILL CONTINUE TO MONITOR
TRENDS CLOSELY OVER THE NEXT FEW HOURS. SPS SHOULD REMAIN SUFFICIENT
OVER THE REST OF THE FORECAST AREA AS FOG LIKELY TO REMAIN PATCHY.
ONCE VISIBILITIES IMPROVE LATER THIS MORNING...REMAINDER OF THE DAY
SHOULD BE FAIRLY QUIET WITH HIGH PRESSURE ACROSS THE REGION. ONE BIG
CAVEAT WILL BE THE LOCATION AND EXTENT OF THE STRATUS DECK AND JUST
HOW QUICKLY THAT MIXES OUT. AT THIS POINT...APPEARS THE DECK WILL
SPREAD ACROSS FAR NORTHWEST PORTIONS OF THE FORECAST AREA LATER THIS
MORNING. HOWEVER...UNCERTAINTY IS VERY HIGH WITH RESPECT TO HOW MUCH
FURTHER SOUTHEAST THE DECK MAY EXPAND INTO THE FORECAST AREA. HAVE
CHOSEN TO CARRY MOSTLY CLOUDY SKIES OVER NORTHWEST COUNTIES WITH
MOSTLY SUNNY/PARTLY CLOUDY CONDITIONS ELSEWHERE. ADJUSTMENTS WILL BE
MADE ACCORDINGLY THROUGH THE MORNING AS NEEDED.
TEMPS...VERY TRICKY FORECAST AS STRATUS DECK WILL PLAY A MAJOR
FACTOR. HAVE LOWERED TEMPS BY 3-5 DEGREES FROM PREVIOUS FORECAST
OVER THE NORTHERN WABASH VALLEY WHERE CONFIDENCE IS HIGHEST WITH
RESPECT TO CLOUD IMPACTS. SHOULD THE DECK HANG FOR LONGER...THESE
FORECAST HIGHS IN THE LOWER 40S ARE LIKELY TO BE TOO WARM. PLACED
TEMPS NEAR MOS GUIDANCE IN THE MID AND UPPER 40S ELSEWHERE.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AND
WEDNESDAY AS A SERIES OF WEAK UPPER LEVEL DISTURBANCES PASS THROUGH
THE LOWER GREAT LAKES.
HIGH PRESSURE RIDGE WILL BRING ANOTHER TRANQUIL NIGHT WITH CLEAR
SKIES TONIGHT. THE RIDGE SHIFTS EAST TUESDAY WITH MID AND HIGH LEVEL
CLOUDS EXPANDING INTO THE REGION FROM THE NORTHWEST. CHANCES FOR
PRECIPITATION ARE LIKELY TO HOLD OFF UNTIL TUESDAY EVENING AS LEAD
SHORTWAVE ASSOCIATED WITHIN LARGER UPPER TROUGH ROTATES ACROSS THE
REGION. ISENTROPIC LIFT AND OVERALL FORCING REMAIN GENERALLY
WEAK...BUT DOES APPEAR ENOUGH MOISTURE PRESENT FOR LIGHT
PRECIPITATION. WHILE A LIGHT RAIN/SNOW MIX IS POSSIBLE OVER SOUTHERN
COUNTIES TUESDAY EVENING...LOW LEVEL THERMALS AND MODEL SOUNDINGS
SHOW PRECIPITATION AS ALL SNOW AFTER MIDNIGHT AS THE BOUNDARY LAYER
AND NEAR SURFACE TEMPS COOL. SHORTWAVE AXIS SWINGS ACROSS THE
FORECAST AREA BETWEEN 06-12Z WEDNESDAY WITH BEST FORCING ALOFT. THIS
LIKELY TO BE THE TIMEFRAME WHEN LIGHT SNOW IS MOST PREVALENT WITH
HIGHEST POPS. APPEARS THERE COULD BE A FEW TENTHS OF AN INCH
ACCUMULATION BY DAYBREAK WEDNESDAY.
SCATTERED LIGHT SNOW SHOWERS WILL PERSIST WEDNESDAY MORNING WITH A
GRADUAL DIMINISHING OF COVERAGE AS BETTER MOISTURE AND FORCING SHIFT
EAST THROUGH THE DAY. CLOUDS AND A FEW FLURRIES LIKELY TO LINGER
UNTIL THE MAIN UPPER TROUGH PASSES WEDNESDAY AFTERNOON. WILL HOLD
ONTO LOW CHANCE POPS ON WEDNESDAY WITH MODEL SOUNDINGS FAVORING ANY
PRECIP TO FALL IN THE FORM OF LIGHT SNOW. NOT ANTICIPATING ANY
ADDITIONAL LIGHT ACCUMS AT THIS POINT. UPPER TROUGH MOVES AWAY TO
THE EAST WEDNESDAY WITH ANOTHER SURGE OF DEEP SUBSIDENCE ADVECTING
INTO THE REGION AS HIGH PRESSURE REESTABLISHES. SKIES SHOULD CLEAR
QUICKLY SETTING THE STAGE FOR A CHILLY NIGHT.
TEMPS...GENERALLY LEANED TOWARDS COOLER METMOS GUIDANCE THROUGH THE
PERIOD...ESPECIALLY TUESDAY NIGHT AND WEDNESDAY WITH CLOUDS AND
PRECIP. COLDEST NIGHT WILL BE WEDNESDAY NIGHT AS LOWS FALL TO NEAR
20 DEGREES UNDER CLEAR SKIES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
QUIET EXTENDED PERIOD FOR THE MOST PART...WITH THE ONLY EXCEPTION
BEING A VERY BROAD UPPER LEVEL TROUGH OVER MUCH OF THE GREAT LAKES
REGION AND MIDWEST ON FRIDAY/FRIDAY NIGHT. LATEST GFS AND EURO
MODEL RUNS ARE SHOWING MORE MOISTURE WITH AN ASSOCIATED COLD
FRONT...BUT INITIALIZATION NUMBERS ARE STILL TRENDING TOWARD A DRY
FRONTAL PASSAGE ON FRIDAY AFTERNOON/EVENING. AT THIS TIME...WILL
NOT MAKE ADJUSTMENTS TO INITIALIZATION NUMBERS UNTIL AFTER A FEW MORE
MODEL RUNS COME IN. OVERNIGHT LOWS WILL BE MORE REPRESENTATIVE FOR
THIS TIME OF YEAR WITH READINGS IN THE UPPER TEENS AND 20S DUE TO
THE CLEAR SKIES. THE AFOREMENTIONED COLD FRONT WILL LOWER DAYTIME
HIGHS A TAD ON SATURDAY...BUT THEY WILL QUICKLY INCREASE BACK INTO
THE UPPER 30S/LOW 40S BY SUNDAY AND MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 06/12Z TAF ISSUANCE/...
FLYING CONDITIONS VERY SIMILAR TO YESTERDAY MORNING. FOG WILL BE
PROBLEMATIC...ESPECIALLY AT KLAF AND KHUF THROUGH MID MORNING.
PLUS...CURRENT SATELLITE IS SHOWING LOW STRATUS DECK MOVING IN
FROM NORTHERN ILLINOIS RAISING CONCERN OVER POSSIBLE TRAPPING OF
DENSE FOG AT AFOREMENTIONED TAF SITES. SO...WILL KEEP TEMPO OF
VLIFR CONDITIONS AT KLAF AND KHUF THROUGH MID MORNING.
ELSEWHERE...CONDITIONS HAVE BEEN BEHAVING AT KIND AND KBMG WITH
VFR CATEGORY UP TO THIS POINT. AT WORST...COULD SEE SOME BRIEF MVFR
CONDITIONS OVER THE NEXT FEW HOURS AT THESE TAF SITES.
BEYOND MID MORNING...VFR CONDITIONS WILL PREVAIL FOR REMAINDER OF
TAF PERIOD. HIGH CLOUDS WILL INCREASE AT TAIL END OF TAF PERIOD AS
THE NEXT DISTURBANCE APPROACHES AREA...BUT THIS WILL HAVE NO
IMPACT ON FLIGHT OPERATIONS.
WINDS WILL BE WESTERLY AT 4 TO 8 KTS FOR THE MAJORITY OF TAF
PERIOD...AND WILL THEN START VEERING TO THE NORTHWEST TOMORROW
MORNING. SUSTAINED WIND SPEEDS WILL INCREASE TO 5 TO 10 KTS.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY UNTIL 11 AM EST THIS MORNING FOR INZ021-
028-029-035-043.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...TDUD
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
617 AM EST MON FEB 6 2012
.UPDATE...
THE NEAR TERM SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL KEEP DRY MILD WEATHER ACROSS CENTRAL INDIANA
THROUGH TUESDAY. A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL
BRING THE CHANCE FOR LIGHT PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER FOR LATE
WEEK AND INTO THE WEEKEND. THE EXPANSION OF A BROAD UPPER LEVEL
TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES BY THE WEEKEND.
&&
.NEAR TERM /TODAY/...
6 AM UPDATE...OBS AND WEBCAMS ACROSS THE NORTHERN WABASH VALLEY
SUGGEST THAT FREEZING FOG HAS BECOME MORE WIDESPREAD. HAVE GONE
AHEAD AND INTRODUCED A FREEZING FOG ADVISORY THROUGH 16Z FOR FAR
NORTHWEST FORECAST AREA. ARRIVAL OF BROAD STRATOCU DECK TO THE WEST
MAY SERVE TO MAINTAIN DENSE FOG INTO LATE MORNING.
EARLY MORNING DISCUSSION FOLLOWS.
CLEAR SKIES OVER A MAJORITY OF THE FORECAST AREA THIS MORNING. ONLY
EXCEPTION IS OVER NORTHERN WABASH VALLEY WHERE SHALLOW FREEZING FOG
AND POCKETS OF LOW STRATUS HAVE FORMED EARLY THIS MORNING. TEMPS AT
08Z WERE BELOW FREEZING...FROM THE MID 20S TO LOWER 30S.
MAIN FORECAST ISSUE FOCUSES ON FREEZING FOG THROUGH MID MORNING AND
POTENTIAL IMPACTS FROM DEVELOPING POCKETS OF STRATUS. BROAD AREA OF
STRATUS WITH CEILINGS AT OR BELOW 500FT CONTINUES TO EXPAND SLOWLY
EAST ACROSS NORTHERN ILLINOIS. MOST OF THE SHORT RANGE MODEL
GUIDANCE IS STRUGGLING MIGHTILY WITH THE LOCATION AND EXPANSION OF
THE LARGER STRATUS DECK OVER ILLINOIS...WITH ONLY THE RUC AND TO A
LESSER EXTENT THE 06Z NAM HINTING AT ITS PRESENCE CURRENTLY. HAVE
INTRODUCED AN SPS FOR FREEZING FOG OVER THE ENTIRE FORECAST AREA
THROUGH MID MORNING WITH THE MAIN CONCERN OVER NORTHWEST COUNTIES
AND THE NORTHERN WABASH VALLEY WHERE MANY LOCATIONS ALREADY
REPORTING BELOW 1SM. AT THIS POINT APPEARS DENSE FOG IN NORTHWEST
COUNTIES REMAINS PATCHY BUT SHOULD IT BECOME MORE WIDESPREAD...MAY
NEED TO CONSIDER A FREEZING FOG ADVISORY. WILL CONTINUE TO MONITOR
TRENDS CLOSELY OVER THE NEXT FEW HOURS. SPS SHOULD REMAIN SUFFICIENT
OVER THE REST OF THE FORECAST AREA AS FOG LIKELY TO REMAIN PATCHY.
ONCE VISIBILITIES IMPROVE LATER THIS MORNING...REMAINDER OF THE DAY
SHOULD BE FAIRLY QUIET WITH HIGH PRESSURE ACROSS THE REGION. ONE BIG
CAVEAT WILL BE THE LOCATION AND EXTENT OF THE STRATUS DECK AND JUST
HOW QUICKLY THAT MIXES OUT. AT THIS POINT...APPEARS THE DECK WILL
SPREAD ACROSS FAR NORTHWEST PORTIONS OF THE FORECAST AREA LATER THIS
MORNING. HOWEVER...UNCERTAINTY IS VERY HIGH WITH RESPECT TO HOW MUCH
FURTHER SOUTHEAST THE DECK MAY EXPAND INTO THE FORECAST AREA. HAVE
CHOSEN TO CARRY MOSTLY CLOUDY SKIES OVER NORTHWEST COUNTIES WITH
MOSTLY SUNNY/PARTLY CLOUDY CONDITIONS ELSEWHERE. ADJUSTMENTS WILL BE
MADE ACCORDINGLY THROUGH THE MORNING AS NEEDED.
TEMPS...VERY TRICKY FORECAST AS STRATUS DECK WILL PLAY A MAJOR
FACTOR. HAVE LOWERED TEMPS BY 3-5 DEGREES FROM PREVIOUS FORECAST
OVER THE NORTHERN WABASH VALLEY WHERE CONFIDENCE IS HIGHEST WITH
RESPECT TO CLOUD IMPACTS. SHOULD THE DECK HANG FOR LONGER...THESE
FORECAST HIGHS IN THE LOWER 40S ARE LIKELY TO BE TOO WARM. PLACED
TEMPS NEAR MOS GUIDANCE IN THE MID AND UPPER 40S ELSEWHERE.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AND
WEDNESDAY AS A SERIES OF WEAK UPPER LEVEL DISTURBANCES PASS THROUGH
THE LOWER GREAT LAKES.
HIGH PRESSURE RIDGE WILL BRING ANOTHER TRANQUIL NIGHT WITH CLEAR
SKIES TONIGHT. THE RIDGE SHIFTS EAST TUESDAY WITH MID AND HIGH LEVEL
CLOUDS EXPANDING INTO THE REGION FROM THE NORTHWEST. CHANCES FOR
PRECIPITATION ARE LIKELY TO HOLD OFF UNTIL TUESDAY EVENING AS LEAD
SHORTWAVE ASSOCIATED WITHIN LARGER UPPER TROUGH ROTATES ACROSS THE
REGION. ISENTROPIC LIFT AND OVERALL FORCING REMAIN GENERALLY
WEAK...BUT DOES APPEAR ENOUGH MOISTURE PRESENT FOR LIGHT
PRECIPITATION. WHILE A LIGHT RAIN/SNOW MIX IS POSSIBLE OVER SOUTHERN
COUNTIES TUESDAY EVENING...LOW LEVEL THERMALS AND MODEL SOUNDINGS
SHOW PRECIPITATION AS ALL SNOW AFTER MIDNIGHT AS THE BOUNDARY LAYER
AND NEAR SURFACE TEMPS COOL. SHORTWAVE AXIS SWINGS ACROSS THE
FORECAST AREA BETWEEN 06-12Z WEDNESDAY WITH BEST FORCING ALOFT. THIS
LIKELY TO BE THE TIMEFRAME WHEN LIGHT SNOW IS MOST PREVALENT WITH
HIGHEST POPS. APPEARS THERE COULD BE A FEW TENTHS OF AN INCH
ACCUMULATION BY DAYBREAK WEDNESDAY.
SCATTERED LIGHT SNOW SHOWERS WILL PERSIST WEDNESDAY MORNING WITH A
GRADUAL DIMINISHING OF COVERAGE AS BETTER MOISTURE AND FORCING SHIFT
EAST THROUGH THE DAY. CLOUDS AND A FEW FLURRIES LIKELY TO LINGER
UNTIL THE MAIN UPPER TROUGH PASSES WEDNESDAY AFTERNOON. WILL HOLD
ONTO LOW CHANCE POPS ON WEDNESDAY WITH MODEL SOUNDINGS FAVORING ANY
PRECIP TO FALL IN THE FORM OF LIGHT SNOW. NOT ANTICIPATING ANY
ADDITIONAL LIGHT ACCUMS AT THIS POINT. UPPER TROUGH MOVES AWAY TO
THE EAST WEDNESDAY WITH ANOTHER SURGE OF DEEP SUBSIDENCE ADVECTING
INTO THE REGION AS HIGH PRESSURE REESTABLISHES. SKIES SHOULD CLEAR
QUICKLY SETTING THE STAGE FOR A CHILLY NIGHT.
TEMPS...GENERALLY LEANED TOWARDS COOLER METMOS GUIDANCE THROUGH THE
PERIOD...ESPECIALLY TUESDAY NIGHT AND WEDNESDAY WITH CLOUDS AND
PRECIP. COLDEST NIGHT WILL BE WEDNESDAY NIGHT AS LOWS FALL TO NEAR
20 DEGREES UNDER CLEAR SKIES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
QUIET EXTENDED PERIOD FOR THE MOST PART...WITH THE ONLY EXCEPTION
BEING A VERY BROAD UPPER LEVEL TROUGH OVER MUCH OF THE GREAT LAKES
REGION AND MIDWEST ON FRIDAY/FRIDAY NIGHT. LATEST GFS AND EURO
MODEL RUNS ARE SHOWING MORE MOISTURE WITH AN ASSOCIATED COLD
FRONT...BUT INITIALIZATION NUMBERS ARE STILL TRENDING TOWARD A DRY
FRONTAL PASSAGE ON FRIDAY AFTERNOON/EVENING. AT THIS TIME...WILL
NOT MAKE ADJUSTMENTS TO INITIALIZATION NUMBERS UNTIL AFTER A FEW MORE
MODEL RUNS COME IN. OVERNIGHT LOWS WILL BE MORE REPRESENTATIVE FOR
THIS TIME OF YEAR WITH READINGS IN THE UPPER TEENS AND 20S DUE TO
THE CLEAR SKIES. THE AFOREMENTIONED COLD FRONT WILL LOWER DAYTIME
HIGHS A TAD ON SATURDAY...BUT THEY WILL QUICKLY INCREASE BACK INTO
THE UPPER 30S/LOW 40S BY SUNDAY AND MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 06/09Z TAF UPDATE/...
UPDATE...
FOG IS PROVING TO BE PROBLEMATIC AT KLAF AND KHUF WITH
VISIBILITIES IN THE LIFR/IFR CATEGORIES. ELSEWHERE...CONDITIONS
ARE HOLDING UP AT KIND AND KBMG...SO TEMPO MVFR THROUGH MON 13Z
STILL LOOKS REASONABLE AT THOSE SITES.
PREVIOUS DISCUSSION...
MAINLY VFR THROUGH THE PERIOD...WITH A PERIOD OF MVFR POSSIBLE NEAR
DAYBREAK TOMORROW.
HIGH PRESSURE HAS BUILT IN...ERODING ANY LEFTOVER CLOUD...AND
ALLOWING SIGNIFICANT DRYING AT THE SURFACE THROUGH A LIGHT NORTHERLY
SURFACE FLOW AND AMPLE SUNSHINE WITH THE SUPERB WEATHER YESTERDAY
AFTERNOON. ALTHOUGH WINDS WILL BE CALM TO LIGHT AND SKIES WILL BE
CLEAR OVERNIGHT...DO NOT EXPECT SIGNIFICANT FOG TO FORM. WILL
INCLUDE SOME HIGH END MVFR FOG FOR A FEW HOURS NEAR DAYBREAK AT ALL
SITES IN TEMPO GROUPS. NAM/RUC SOUNDINGS SHOW DECENT SATURATION NEAR
THE SURFACE...GFS/SREF SOUNDINGS DO NOT. NAM SOUNDING IS MOST
FAVORABLE...BUT ITS 00Z MOS DOES NOT BRING ANY RESTRICTIONS IN.
WINDS WILL BE CALM TO LIGHT OVERNIGHT...BECOMING WEST/SOUTHWESTERLY
TOMORROW BUT REMAINING BELOW 10KT. MAY SEE INFREQUENT GUSTS INTO THE
LOW TEENS BUT SURFACE PRESSURE GRADIENT APPEARS FAIRLY WEAK...SO
WILL NOT INCLUDE ANY MENTION AT THIS TIME.
&&
.IND WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...RYAN
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...NIELD/TDUD
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
933 AM EST MON FEB 6 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY WEATHER THROUGH TUESDAY. A SOUTHBOUND
CANADIAN COLD FRONT WILL BRING SCATTERED SNOW SHOWERS LATE TUESDAY NIGHT
AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
PLENTY OF SUNSHINE IS FORECAST TODAY WITH HIGH PRESSURE MOVING
THROUGH THE OHIO VALLEY.
A FEW CUMULUS CLOUDS COULD FORM MAINLY ACROSS NORTHERN ZONES AND
ALONG THE RIDGES THIS AFTERNOON. OTHERWISE SKIES SHOULD BE CLEAR.
HIGH TEMPERATURES WILL BE 5 TO 8 DEGREES WARMER THAN NORMAL BASED
ON BLEND OF RECENT GFS MOS, LAMP, AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
UPPER LEVEL SYSTEM WILL MOVE THROUGH THE OHIO VALLEY TONIGHT WITH
COLD FRONT PUSHING THROUGH ON TUESDAY. MODELS ARE SHOWING VERY
LITTLE MOISTURE WITH THE FRONT, SO WILL LEAVE FORECAST DRY.
COLD ADVECTION BEHIND FRONT WILL BRING COLDER TEMPS TUESDAY NIGHT.
FRONT WILL STALL OVER THE MID-ATLANTIC LATE TUESDAY NIGHT AND AN
UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE OHIO VALLEY
WEDNESDAY. MOISTURE WILL ACCOMPANY THE NEXT WAVE AND WILL BRING
THE CHANCE FOR SNOW SHOWERS TO AT LEAST THE SOUTHERN HALF OF THE
REGION. ANOTHER PERIOD OF CAA WILL OCCUR BEHIND THE WAVE ON
WEDNESDAY.
ABOVE NORMAL TEMPS TUESDAY WILL BE FOLLOWED BY BELOW NORMAL TEMPS
ON WEDNESDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BLEND OF RECENT ECMWF AND GFS MODEL OUTPUT SHOWS A DEEP UPPER LOW
PASSING EASTWARD THROUGH EASTERN CANADA LATE IN THE WEEK. A COLD
FRONT WILL PASS THROUGH THE UPPER OHIO VALLEY BY LATE FRIDAY
BRINGING SCATTERED RAIN/SNOW SHOWERS AND A RETURN TO MORE
SEASONABLE TEMPERATURES. SURFACE HIGH PRESSURE AND DRIER AIR WILL
MOVE OVER THE APPALACHIANS BY SUNDAY.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL MAINTAIN VFR CONDITIONS THROUGH TONIGHT, WITH
SCATTERED CUMULUS CLOUDS THIS AFTERNOON. SOUTHWEST WINDS CAN REACH
10-15 KTS THIS AFTERNOON.
OUTLOOK...TONIGHT THROUGH FRIDAY...
VFR TUESDAY. SCATTERED COLD FRONTAL SNOW SHOWERS WITH RESTRICTIONS
POSSIBLE LATE TUESDAY NIGHT AND WEDNESDAY. VFR THURSDAY AND FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS PITTSBURGH PA
646 AM EST MON FEB 6 2012
.SYNOPSIS...
HIGH PRESSURE WILL BRING DRY WEATHER THROUGH TUESDAY. A SOUTHBOUND
CANADIAN COLD FRONT WILL BRING SCATTERED SNOW SHOWERS LATE TUESDAY NIGHT
AND WEDNESDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
QUIET WEATHER TODAY WITH HIGH PRESSURE MOVING THROUGH THE OHIO
VALLEY. PER RECENT SATELLITE DATA, ADDED MENTION OF FOG PATCHES
ACROSS THE HIGHER PA-WV-MD MOUNTAINS TIL 9 AM.
PLENTY OF SUNSHINE WITH SOME CUMULUS CLOUDS POSSIBLE THIS
AFTERNOON. HIGH TEMPERATURES WILL BE 5 TO 8 DEGREES WARMER THAN
NORMAL BASED ON BLEND OF RECENT GFS MOS, LAMP, AND HRRR MODEL OUTPUT.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
UPPER LEVEL SYSTEM WILL MOVE THROUGH THE OHIO VALLEY TONIGHT WITH
COLD FRONT PUSHING THROUGH ON TUESDAY. MODELS ARE SHOWING VERY
LITTLE MOISTURE WITH THE FRONT, SO WILL LEAVE FORECAST DRY.
COLD ADVECTION BEHIND FRONT WILL BRING COLDER TEMPS TUESDAY NIGHT.
FRONT WILL STALL OVER THE MID-ATLANTIC LATE TUESDAY NIGHT AND AN
UPPER LEVEL DISTURBANCE WILL MOVE THROUGH THE OHIO VALLEY
WEDNESDAY. MOISTURE WILL ACCOMPANY THE NEXT WAVE AND WILL BRING
THE CHANCE FOR SNOW SHOWERS TO AT LEAST THE SOUTHERN HALF OF THE
REGION. ANOTHER PERIOD OF CAA BEHIND THE WAVE ON WEDNESDAY.
ABOVE NORMAL TEMPS TUESDAY, WILL BE FOLLOWED BY BELOW NORMAL TEMPS
ON WED.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
BLEND OF RECENT ECMWF AND GFS MODEL OUTPUT SHOWS A DEEP UPPER LOW
PASSING EASTWARD THROUGH EASTERN CANADA LATE IN THE WEEK. A COLD
FRONT WILL PASS THROUGH THE UPPER OHIO VALLEY BY LATE
FRIDAY, BRINGING SCATTERED RAIN/SNOW SHOWERS AND A RETURN TO MORE
SEASONABLE TEMPERATURES. SURFACE HIGH PRESSURE AND DRIER AIR WILL
MOVE OVER THE APPALACHIANS BY SUNDAY.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
HIGH PRESSURE WILL MAINTAIN VFR CONDITIONS THROUGH TONIGHT, WITH
SCATTERED CUMULUS CLOUDS THIS AFTERNOON. SOUTHWEST WINDS CAN REACH
10-15 KTS THIS AFTERNOON.
OUTLOOK...TONIGHT THROUGH FRIDAY...
VFR TUESDAY. SCATTERED COLD FRONTAL SNOW SHOWERS WITH RESTRICTIONS
POSSIBLE LATE TUESDAY NIGHT AND WEDNESDAY. VFR THURSDAY AND FRIDAY.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
OH...NONE.
PA...NONE.
WV...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
638 AM EST MON FEB 6 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(404 AM EST MON FEB 6 2012)
A COLD FRONT WILL CROSS THE REGION TONIGHT. THIS SYSTEM WILL BRING
VERY LITTLE SNOW...HOWEVER IT WILL RETURN TEMPERATURES TO NEAR
NORMAL VALUES FOR MID WEEK. ANOTHER SURGE OF COLDER AIR ARRIVES BY
FRIDAY AND INTO THE WEEKEND. SOME LAKE EFFECT SNOW SHOWERS WILL BE
SEEN ALONG WITH THIS COLDER AIR.
&&
.SHORT TERM...(404 AM EST MON FEB 6 2012)
(TODAY THROUGH WEDNESDAY)
THE SKY FORECAST REMAINS THE BIGGEST CHALLENGE TODAY AND THE
RESULTANT AFFECTS ON THE REGION/S TEMPS. A LARGE AREA OF STRATUS
COVERED MUCH OF WISCONSIN THIS MORNING AND IT WAS PRESSING EASTWARD
AT A 5-10 MPH PACE. THAT SPEED ALONG WOULD SUGGEST THAT THE CLOUD
DECK WOULD NOT REACH THE MICHIGAN SHORE UNTIL MID AFTERNOON.
HOWEVER THERE WAS ALSO RANDOM PATCHES OF STRATUS ACROSS LOWER
MICHIGAN TOO. THE RUC LOW LEVEL MOISTURE PROGS SUGGEST A RAPID
EXPANSION OF THE STRATUS SO THAT THE ENTIRE GRR CWA IS COVERED BY
CLOUDS BY 12Z. THIS LOOKS UNREASONABLE TO ME. HOWEVER BELIEVE THE
STRATUS WILL LIKELY SPEED UP IT/S EASTWARD TRACK AS IT MOVES ACROSS
THE LAKE THIS MORNING. ALSO...THE RANDOM PATCHES MAY ALSO EXPAND
SOMEWHAT THIS MORNING. BUT THEN THE ISSUE BECOMES...WHAT WILL THE
INCREASED MIXING DO TO THE STRATUS. I SENSE THAT IT WILL HELP IT TO
ERODE SUCH THAT MUCH OF THE STRATUS BECOMES LESS OF A FACTOR BY MID
DAY. SO I WILL PLAY THE FORECAST SUCH THAT SOME STRATUS WILL LINGER
THROUGH THE MORNING...BUT WILL BANK ON A MOSTLY SUNNY AFTERNOON AS
THE EASTWARD EDGE OF THE STRATUS MIXES OUT. IF THIS INDEED OCCURS
TEMPS WILL REACH WELL INTO THE 40S AGAIN TODAY...IF IT DOES NOT
OCCUR TEMPS MAY HOLD FROM 35 TO 40.
THE ARCTIC FRONT IS STILL ON SCHEDULE FOR TONIGHT. THE LACK OF DEEP
MOISTURE WILL RESULT IN NO SNOW OR PERHAPS A RANDOM FLURRY. THE LOW
LEVEL FLOW BEHIND THE FRONT SHOULD BE 030-040...KEEPING ANY LAKE
EFFECT ON THE OTHER SIDE OF THE LAKE. WE WILL HAVE TO KEEP AN EYE
ON POSSIBLE SNOW SHOWERS OFF OF SAGINAW BAY WHICH MAY MOVE INTO
AREAS AROUND ST. JOHNS BY TUESDAY.
HAVE LOW POPS IN FOR TUE AFTERNOON INTO TUESDAY NIGHT FOR AREAS
SOUTH OF I-96. A SHORT WAVE COMES ACROSS THE LOWER GREAT LAKES AND
COMBINED WITH THE EXITING ARCTIC FRONT MAY PRODUCE SOME LIGHT SNOW.
LOW LEVEL WINDS SHOULD ALSO BACK TO THE NW BY LATE TUESDAY NIGHT
WHICH COULD BRING A FEW SNOW SHOWERS OFF THE LAKE. BY WEDNESDAY THE
MOISTURE PROFILE BECOMES VERY SHALLOW AS RIDGING BUILDS INTO THE
AREA. EXPECT SUNSHINE WITH NEAR NORMAL TEMPS.
&&
.LONG TERM...(404 AM EST MON FEB 6 2012)
(WEDNESDAY NIGHT THROUGH SUNDAY)
A CLIPPER MOVES ACROSS NORTHERN LOWER MICHIGAN THURSDAY NIGHT
SWINGING AN ARCTIC FRONT SOUTH ACROSS THE FORECAST AREA.
LOOKS LIKE SOME SNOW WILL ACCOMPANY THE FROPA WITH STRONG SFC
CONVERGENCE. LAKE EFFECT BEHIND THE FRONT WILL CONTINUE INTO
SATURDAY BUT FLOW GOES NORTH AND THEN EVENTUALLY NORTHEAST WHICH
WOULD PUSH THE SNOW SHOWERS OFFSHORE. THIS COMBINED WITH INVERSION
HEIGHTS BELOW 10 KFT SHOULD LIMIT ACCUMS...WITH MOST OF THE SNOW
CONCENTRATED FAIRLY CLOSE TO THE LAKE MICHIGAN SHORE.
&&
.AVIATION...(638 AM EST MON FEB 6 2012)
THIN STRATUS WITH MVFR AND PATCHY IFR CEILINGS WILL BE ACROSS LOWER
MICHIGAN THIS MORNING. WILL HAVE A TEMPO GROUP FOR IFR CEILINGS AND
MVFR FOG THROUGH 16Z. SOME THINNING OF THE CLOUDS SHOULD OCCUR BY
AFTERNOON.
A COLD FRONT MOVES IN WITH A THICKER BAND OF CLOUDS AND PERHAPS
FZDZ AFTER MIDNIGHT. DID NOT INCLUDE IN THE FORECAST AT THIS TIME
SINCE PROBABILITY SEEMS LOW.
&&
.MARINE...(404 AM EST MON FEB 6 2012)
SCA IN AFFECT FOR TODAY WITH WSW WINDS TO AROUND 20 KTS. LOOKS LIKE
WE WILL SEE A BRIEF BREAK IN THE HIGHER WINDS AND WAVES EARLY
TONIGHT AS A COLD FRONT COMES THROUGH. BUT THEN BEHIND THE FRONT
WAVES SHOULD INCREASE AGAIN LATE TONIGHT OR EARLY TUESDAY IN THE
COLD ADVECTION PATTERN.
&&
.HYDROLOGY...(404 AM EST MON FEB 6 2012)
MINIMAL HYDRO CONCERNS GIVEN THE LACK OF PCPN. ALSO THE SNOW PACK
TO THE NORTH WILL END IT/S MELTING BY TONIGHT AS THE COLD FRONT
COOLS REGIONAL TEMPS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY ST. JOE TO MANISTEE THROUGH TODAY.
&&
$$
SYNOPSIS: JK
SHORT TERM: JK
LONG TERM: OSTUNO
AVIATION: OSTUNO
MARINE: JK
HYDROLOGY: JK
AREA FORECAST DISCUSSION
NWS GAYLORD MI
632 AM EST MON FEB 6 2012
.SYNOPSIS.../ISSUED AT 347 AM/
HIGH PRESSURE ACROSS THE REGION THROUGH MIDDAY WILL GIVE WAY TO AN
APPROACHING COLD FRONT BY EVENING. THE PASSAGE OF THIS FRONT WILL
USHER IN A BRIEF SHOT OF MUCH COLDER WEATHER FOR THE DAY ON
TUESDAY...ALONG WITH CHANCES FOR SOME LIGHT SNOW SHOWERS.
TEMPERATURES WILL WARM BACK ABOVE NORMAL BY THURSDAY AS HIGH
PRESSURE AGAIN ARRIVES...BEFORE ANOTHER PUSH OF COLD WEATHER AND
LAKE SNOW SHOWERS ARRIVES FOR FRIDAY INTO THE WEEKEND.
DL
&&
.SHORT TERM.../ISSUED AT 347 AM/...TODAY
A SHARP COLD FRONT IS MOVING SOUTH TOWARD THE NORTH SHORE OF
SUPERIOR EARLY THIS MORNING. THERE IS NO PRECIP...AND IN FACT NO
CLOUDS...WITH THE FRONT ITSELF...THOUGH LOW CLOUDS ARE EXTENSIVE
BEHIND IT. IN THE WARM SECTOR...A FEW PATCHES OF LOW CLOUDS REMAIN
OVER MI AND ENVIRONS...WITH MORE WIDESPREAD CLOUD COVER IN THE UPPER
MS VALLEY AND EXPANDING ESE-WARD. CLOUD/TEMP TRENDS ARE AGAIN
THE MAIN CONCERN TODAY.
COLD FRONT WILL REACH EASTERN UPPER MI TOWARD 18Z...AND WILL BE
NEARING SAGINAW BAY AT 00Z. OUTSIDE OF VERY SHALLOW SURFACE-BASED
MOISTURE...THE DEEP AIRMASS IN THE WARM SECTOR REMAINS VERY DRY
(850-700MB RH LESS THAN 30 PERCENT...PWATS 0.25-0.30). THERE IS NO
RISK OF PRECIP AHEAD OF...OR WITH...THE FRONT. HOWEVER...CLOUD
TRENDS IN THE WARM SECTOR REMAIN PROBLEMATIC. THE AIRMASS BELOW
925MB REMAINS MOIST (SURFACE DEW POINTS REFLECT THIS). LARGER LOW
CLOUD MASS TO OUR WEST IS TRYING TO WORK EAST THIS MORNING...BEFORE
MIXING CAN EAT AWAY AT IT TOO MUCH. DOWNSLOPING WINDS INTO FAR
EASTERN WI ARE KEEPING THE CLOUD MASS FROM ADVANCING AS FAR EAST AS
IT COULD. MODEL GUIDANCE IS ALL OVER THE MAP...FROM THE NAM NOT
ALLOWING ANY LOW CLOUDS TO CROSS THE LAKE...TO THE HRRR WHICH
COMPLETELY SOCKS IN ALL OF NORTHERN MI BY 16Z.
GIVEN SATELLITE TRENDS OF AN CLOUD MASS CLEARLY STRUGGLING TO MOVE
EAST...WILL NOT BRING IN OVERCAST SKIES THIS MORNING. WE/RE STILL
PLENTY MOIST DOWN LOW...AND SMALL PATCHES OF LOW CLOUDS COULD FORM
JUST ABOUT ANYWHERE THIS MORNING. WE MAY ALSO BE NEED MOIST ENOUGH
TO QUICKLY FIRE A SHALLOW CU DECK BEFORE MIXING IT OUT TOWARD
MIDDAY.
BEHIND THE FRONT...LOW CLOUDS WILL BECOME EXTENSIVE FROM NORTH TO
SOUTH DURING THE AFTERNOON. THERE MAY BE AN OUTSIDE SHOT AT A BIT OF
DRIZZLE OR SOME FLURRIES IN CENTRAL/WESTERN CHIPPEWA CO VERY LATE.
INVERSION-TOP (875MB) TEMPS REACH -7/8C (SO DELTA T/S INTO THE LOWER
TEENS).
MAX TEMPS WILL AGAIN BE QUITE MILD. WILL FAVOR WARMER GUIDANCE
NUMBERS GIVEN A BALMY START TO THE DAY. MAX TEMPS MID/UPPER 30S
NORTH TO MID 40S FAR SE.
JZ
&&
.LONG TERM.../ISSUED AT 347 AM/...TONIGHT AND BEYOND
THE UPPER TROF FORCING TODAY/S COLD FRONT WON/T ACTUALLY MAKE IT TO
OUR NEIGHBORHOOD UNTIL LATE TUESDAY. LOW LEVEL COLD ADVECTION WILL
CONTINUE UNTIL THEN (THOUGH THE AIRMASS SHOULD MODERATE WITH SOME
SUNSHINE TUESDAY). DESPITE REASONABLE INSTABILITY...THE POOR NORTH
FETCH...LACK OF MOISTURE...AND ARRIVAL OF SURFACE RIDGING/
ANTICYCLONIC CURVATURE WILL LIMIT LAKE EFFECT SNOW (LES) POTENTIAL.
AS HIGH PRESSURE PRESSES SOUTH INTO THE CENTRAL PLAINS BY
WEDNESDAY...WESTERLY LOW LEVEL FLOW AND WARM ADVECTION WILL AGAIN BE
RE-ESTABLISHED HERE. THAT WILL BE BRIEF...AS A STRONGER SHOT OF COLD
AIR APPEARS LIKELY AT THE END OF THE WORK WEEK. TEMP/PRECIP
TRENDS...MAINLY ASSOCIATED WITH THE COLD AIR TONIGHT/TUESDAY AND
AGAIN AT THE END OF THE WEEK...ARE THE MAIN CONCERNS.
TONIGHT...COLD FRONT WILL MOVE SOUTH OF MI...WHILE 500MB TROF WILL
ADVANCE TO NORTHERN SUPERIOR. SURFACE HIGH PRESSURE WILL MOVE INTO
ND...WITH RIDGING EXTENDING JUST NORTH OF SUPERIOR. 1000-850MB WINDS
WILL BECOME N/NNW BY 03Z...AND N/NNE BY 12Z. WE DO MANAGE TO GET
850-700MB RH LEVELS UP TO 60 PERCENT OR SO...IN THE EVENING AROUND
EASTERN UPPER...EXPANDING SOUTH OVERNIGHT (DRYING OUT ON EASTERN
SUPERIOR TOWARD 12Z). DELTA T/S REACH IN THE MID TEENS IN THE
OVERNIGHT HOURS...WHICH SHOULD SPOT OUT A FEW SNOW SHOWERS IN FAR
WESTERN AND FAR EASTERN SECTIONS OF THE FORECAST AREA (GIVEN
UNFAVORABLE N FETCH). WILL KEEP POPS QUITE SMALL...NAM/LOCAL WRF IN
EXCELLENT AGREEMENT IN GENERATING NO QPF ANYWHERE IN THE FORECAST
AREA TONIGHT. MEANWHILE...THE I-75/US-127 CORRIDOR IN NORTHERN
LOWER...AND FAR EASTERN UPPER...SHOULD CLEAR PARTIAL CLEARING. MIN
TEMPS WILL RANGE FROM MID/UPPER SINGLE DIGITS IN FAR EASTERN
UPPER...TO LOWER 20S IN SOME SOUTHERN SECTIONS.
TUESDAY...THE MAIN FACTOR IS THE STRONG SURFACE RIDGE THAT CROSSES
SUPERIOR AND SETTLES ACROSS UPPER/FAR NORTHERN LOWER MI BY 00Z.
ASSOCIATED DRYING (850-700MB RH GO BELOW 25 PERCENT) AND
ANTICYCLONICALLY CURVED FLOW WILL COMPLETELY PUT THE KIBOSH ON LES
AS THE DAY PROCEEDS...DESPITE CONTINUED PRESENCE OF CHILLY AIR
(DELTA T/S MID TEENS). EXPECT CLOUD COVER TO ERODE AS WELL AS WE
MOVE THRU THE AFTERNOON. WILL CONTINUE WITH A SMALL CHANCE OF -SHSN
IN THE MORNING ALONG WESTERN AND EASTERN FRINGES OF THE FORECAST
AREA...AND GO DRY IN THE AFTERNOON. MAX TEMPS UPPER TEENS TO MID 20S.
TUE NIGHT THRU WED NIGHT...SURFACE RIDGE AXIS WILL CONTINUE TO MOVE
SOUTH ACROSS LOWER MI TUESDAY NIGHT...AND WILL EVENTUALLY REACH THE
OHIO VALLEY BY THURSDAY MORNING. BY THEN...THE NEXT COLD FRONT WILL
BE REACHING SUPERIOR. IN BETWEEN...WESTERLY 1000-850MB WINDS WILL
KICK THE COLD AIR OUT FOR A BIT...WITH 850MB TEMPS REACHING -6C BY
WEDNESDAY EVENING. THIS AIRMASS WILL REMAIN QUITE DRY IN THE MID AND
UPPER LEVELS...THOUGH WE MAY AGAIN BE CONTENDING WITH OCCASIONAL LOW
CLOUD ISSUES (ESPECIALLY WEDNESDAY NIGHT) LIKE WE/VE SEEN THE LAST
SEVERAL DAYS. STILL...PARTLY CLOUDY TO MOSTLY CLEAR WILL COVER MUCH
OF THESE PERIODS...WITH NO RISK FOR PRECIP. MIN TEMPS WILL BE QUITE
CHILLY TUE NIGHT...SINGLE DIGITS TO MID TEENS. MAX TEMPS WEDNESDAY
MID 20S TO LOWER 30S. MIN TEMPS WED NIGHT MID TEENS TO LOWER 20S.
JZ
LATER PERIODS (THURSDAY THROUGH SUNDAY)...BRIEF PATTERN CHANGE STILL
ANTICIPATED HEADING INTO THE WEEKEND...AS STRONG MERIDIONAL RIDGING
BUILDING UP THE WEST COAST OF NORTH AMERICA BRIEFLY DISLODGES THE
POLAR VORTEX TOWARD HUDSON BAY. HOWEVER...AS MENTIONED IN THIS SPACE
SEVERAL TIMES THE PAST FEW DAYS...THE PATTERN CHANGE STILL LOOKS TO
BE VERY BRIEF...WITH THE COLDEST AIR RELEGATED TO FRIDAY AND
SATURDAY DAY WHEN H8 TEMPS ARE STILL PROGGED BY MAJORITY OF 00Z
GUIDANCE TO DIP TO AROUND -21C OR SO AT THEIR COLDEST. OVERALL
HEMISPHERIC PATTERN DURING THE WEEKEND TIMEFRAME IS RATHER
UNSTABLE...FEATURING A WAVERING 3-4 WAVE PATTERN...AND THUS NO REAL
SURPRISE TO SEE GUIDANCE CONTINUING EARLIER TRENDS OF ERASING THE
BRIEF PATTERN SHIFT AS STRONG PACIFIC JET ENERGY AGAIN PLOWS THROUGH
MUCH OF THE CONUS. THIS SHOULD RAPIDLY SHIFT THE CORE OF COLDEST AIR
TO THE EAST BY SUNDAY...WITH THE STRONG POSSIBILITY FOR ANOTHER
ROUND OF QUITE WARM WEATHER (BY FEBRUARY STANDARDS AT LEAST) TO
ARRIVE INTO THE FOLLOWING WEEK...THOUGH THAT`S GETTING A BIT AHEAD
OF THINGS FOR THIS FCST.
LOOKING AT THE SPECIFICS...STILL LOOKS LIKE A PERIOD OF SOME LAKE
EFFECT SNOW SHOWERS (BASICALLY A GIVEN) AS COLDER AIR POURS INTO THE
AREA LATER THURSDAY THROUGH SATURDAY...WITH TRENDS THE PAST FEW DAYS
STILL SUGGESTING A MEAN NORTHERLY COMPONENT TO THE LOW LEVEL FLOW.
THAT SAID...MESOSCALE PROCESSES MAY INCREASINGLY COME INTO PLAY BY
SATURDAY AS LOW LEVEL FLOW BECOMES INCREASINGLY ANTICYCLONIC BUT
OVERLAKE INSTABILITY REMAINS STELLAR. WHILE OVERALL MOISTURE
PROFILES DURING THE FRIDAY/SATURDAY TIMEFRAME ARE NOTHING REALLY
IMPRESSIVE...DEPTH OF THE DGZ THROUGH THE LAKE-INDUCED CLOUD LAYER
DOES ARGUE THAT SOME LOCALIZED MODEST FLUFFY ACCUMULATIONS WILL BE
POSSIBLE...MAINLY DOWNWIND OF GRAND TRAVERSE BAY AND PERHAPS INTO
FAR NORTHWESTERN CHIPPEWA COUNTY. SNOW SHOWER CHANCES WILL DWINDLE
QUICKLY HEADING THROUGH THE DAY ON SUNDAY AS LOW LEVEL INSTABILITY
WANES...WITH AN OVERWHELMING MAJORITY OF GUIDANCE SIGNALS SUGGESTING
H8 TEMPS MODIFY INTO THE SINGLE DIGITS BELOW ZERO BY 00Z MONDAY.
TEMPS THROUGH THE EXTENDED WILL FINALLY BE A BIT BELOW NORMAL FOR
ONCE.
LAWRENCE
&&
.MARINE.../ISSUED AT 347 AM/
SOMEWHAT BLUSTERY WEST WINDS WILL CONTINUE UNTIL A COLD FRONT...NOW
NEARING SUPERIOR...CROSSES NORTHERN MI THIS AFTERNOON AND EARLY
EVENING. SMALL CRAFT ADVISORIES ALREADY UP FOR ALL WATERS...AND WILL
REMAIN UNCHANGED. COLD NORTH WINDS MAY SUPPORT ADVISORIES INTO
TONIGHT (ESPECIALLY AS INSTABILITY INCREASES)...BUT WILL HOLD OFF ON
ANY EXTENSIONS AT THIS TIME.
JZ
&&
.AVIATION.../ISSUED AT 632 AM/...VALID FOR 12Z TAFS
LOW CLOUDS (MVFR) ARE REDEVELOPING RIGHT OVER MBL...AND WILL BE
SKIRTING BY TVC AS WELL THIS MORNING. OTHERWISE...CONDITIONS WILL BE
VFR TODAY UNTIL MID AFTERNOON...WHEN A COLD FRONT INVADES FROM THE
NORTH. MVFR CLOUDS WILL BE WIDESPREAD BEHIND THE FRONT...EXPANDING
INTO ALL TAF SITES BY EARLY EVENING...AND LASTING THRU TONIGHT.
JZ
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
LHZ345>349.
LM...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR
LMZ323-341-342-344>346.
LS...NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
623 AM EST MON FEB 6 2012
UPDATED AVIATION DISCUSSION FOR 12Z TAFS
.SYNOPSIS...
IN CONTRAST TO LAST COUPLE NIGHTS...CLEAR SKIES ARE DOMINANT ACROSS
UPR MI THIS MORNING. STRATUS IS NOT TOO FAR AWAY THOUGH OVR MN AND
WI. SO FAR...THERE IS ENOUGH WIND OVR UPR MI TO PROHIBIT THE STRATUS
FM SURGING INTO UPR MI. COLD FRONT THAT WILL BRING A CHANGE TO THE
RECENT UNSEAONABLE WARMTH IS DROPPING ACROSS MANITOBA AND ONTARIO
THIS MORNING. STRATOCU IS INITIAL SIGN OF THE COLDER AIR WITH SFC
OBS TURNING UP SOME LGT SNOW BEHIND THE FRONT OVR NORTHERN ONTARIO.
COLDER AIR ARRIVING LATE TODAY AND TONIGHT WILL LEAD TO LK EFFECT
SNOW SHOWERS OVR NORTHERN UPR MI. AS HAS BEEN CASE MUCH OF THIS
WINTER...THIS COOL DOWN WILL BE BRIEF WITH TEMPERATURES MOVING BACK
TOWARD NORMAL AS SOON AS WEDNESDAY. APPEARS THAT MORE SUBSTANTIAL
COOL DOWN WILL RETURN BY LATE WEEK INTO THE WEEKEND AS PORTION OF
POLAR VORTEX OVER EASTERN CANADA SLIDES INTO GREAT LAKES/NORTHEAST
CONUS.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...
IN THE NEAR TERM...QUIET CONDITIONS AS SKIES SHOULD STAY MOSTLY
CLEAR. RUC13 PERFORMED WELL WITH STRATUS YDY...AND IT DOES INDICATE
STRATUS MAY TRY TO MAKE MOVE INTO SW FRINGES OF UPR MI FM WISCONSIN.
SINCE RUC13 IS OVERDOING NORTHERN EXTENT TO CLOUDS AT THIS HOUR...WILL
KEEP WITH MAINLY CLEAR SKIES. DESPITE THE CLEAR SKIES...TEMPS ARE
STILL IN THE UPR 20S TO LOWER AND EVEN MID 30S WITH STEADY WEST WINDS
BLOWING AHEAD OF COLD FRONT DROPPING ACROSS ONTARIO. ISOLATED INLAND
LOCATIONS WHERE WINDS GO CALM COULD STILL FALL TO LOW-MID 20S THROUGH
SUNRISE /ALREADY HAVE SOME 25F READINGS AT WAKEFIELD AND DOE
LAKE/...BUT FOR LARGE PART TEMPS WILL REMAIN STEADY ELSEWHERE.
TODAY...
COLD FRONT FCST TO MOVE INTO FAR NORTH CWA TOWARD MIDDAY. FRONT
SHOULD REACH SOUTHERN CWA AROUND KMNM BY 21Z THIS AFTN. STRATOCU MAIN
ISSUE INITIALLY AS THERE IS NOT A LOT OF COLD AIR AROUND JUST IN WAKE
OF FRONT...WITH H85 TEMPS WARMER THAN -8C. KEPT ISOLATED SNOW SHOWERS
RESTRICTED TO NW CWA THIS AFTN AS COOLER AIR GRADUALLY FILTERS INTO
UPR MI. OTHERWISE...BASED ON UPSTREAM TRENDS IN ONTARIO THIS
MORNING...MOST AREAS COULD SEE SOME FLURRIES JUST IN WAKE OF FROPA.
TEMPS SHOULD FALL OFF WITH PASSAGE OF FROPA...BUT DOES APPEAR THAT
SHARPER COOLING IS LAGGING INITIAL SURGE OF STRATOCU BY A FEW HOURS.
HEADED TOWARD REGIONAL CANADIAN FOR TEMPERATURE TRENDS TODAY. BASED
ON WARM START THIS MORNING AND WEST WINDS ALREADY STIRRING...SEEMS
LIKELY THAT DOWNSLOPE AREAS OF CNTRL /MARQUETTE TO ESCANABA TO
MENOMINEE/ HAVE SHOT TO REACH INTO 40S BY EARLY AFTN JUST AHEAD OF
FRONT. BY LATE AFTN...EXPECT MOST AREAS TO BE AT OR BLO
FREEZING...WITH 20S LIKELY IN THE HIGHER TERRAIN OF NW AND NCNTRL UPR
MI.
TONIGHT INTO TUESDAY...
REALLY GOOD AGREEMENT ON SPECIFICS FM 00Z GUIDANCE WITH EXTENT AND
DEPTH OF COLD AIR /H85 TEMPS AROUND -15C/ AND MOISTURE /AT LEAST UP
TO 5KFT WHICH INTERSECTS IDEAL DENDRITIC SNOW GROWTH ZONE/. WIND
FIELDS ARE ALSO IN GOOD AGREEMENT WHICH IS A PLUS WHEN DEALING WITH
LK EFFECT. HAVE LEANED ON BLEND OF HIGHER RESOULTION 5KM NAM AND NCEP
HIGH RES WRF-ARW/NMM FOR POP/QPF DETAILS FOR LK EFFECT. IN REALITY
THIS DID NOT RESULT IN MUCH CHANGE TO PREVIOUS FCST. ONLY EXCEPTION
WAS TO TRIM LK EFFECT POPS BACK OVR MUCH OF GOGEBIC/ONTONAGON/IRON AS
BLYR WINDS ARE NOW NORTHEAST COMPARED TO NORTH. DIFFLUENCE SHOWS UP
IN WINDS OVR WESTERN INTERIOR UPR MI AS WELL...SUGGESTING THAT LK
EFFECT IN THE WEST SHOULD STAY PINNED CLOSER TO LK SUPERIOR SHORE
/KIWD THROUGH PORCUPINE MOUNTAINS AND ALONG SHORE AT ONTONAGON UP
INTO KEWEENAW/.
AT THE SAME TIME...LOW-LEVEL FLOW IS MORE CYCLONIC AND FM THE NNE
OVR NCNTRL CWA FOR MUCH OF THE NIGHT LEADING TO BETTER CHANCE OF
SEEING MODERATE SNOW AMOUNTS. FCST SOUNDINGS SHOW MOISTURE THROUGH H8
/7KFT/ THROUGH ABOUT 09Z THEN MOISTURE SETTLES BLO H85/5KFT TOWARD
DAYBREAK TUESDAY. OVER-WATER INSTABILITY IS SUFFICIENT FOR MODERATE
LAKE EFFECT AS LAKE INDUCED EQL RISE UP OVR 5KFT WITH SFC-H85 DELTA
T/S NEARING 20C. LK EFFECT SNOW PARAMETER PICKS UP ON THIS AND
DEEPER MOISTURE/UNIDIRECTIONAL LOW-LEVEL WINDS WITH POCKET OF HIGHER
VALUES BTWN 03Z AND 09Z TONIGHT. LOCAL LK EFFECT GUIDANCE SUGGESTS
12 HR SNOW AMOUNTS UP TO 6 INCHES IN THIS SETUP. UNDERCUT THIS
SLIGHTLY SINCE IDEAL LK EFFECT CONDITIONS WILL PROBABLY
ONLY BE REALIZED FOR 6-9 HRS DUE TO MARGINAL COLD AIR INITIALLY
TONIGHT AND DEEPER MOISTURE PULLING AWAY IN THE 09Z-12Z PERIOD.
THESE NEGATIVES MAY BE OFFSET BY HIGHER SLR/S AND FLUFFY NATURE OF
THE SNOW SINCE MAJORITY OF MOIST CONVECTIVE LAYER IS IN THE HEART OF
THE DGZ. SNOW RATIOS FM NAM COBB OUTPUT ARE IN THE 20-25:1.
EVEN AS DEEPER MOISTURE LEAVES FIRST THING TUESDAY MORNING...EXPECT
COVERAGE OF SNOW SHOWERS TO REMAIN HIGH THROUGH MOST OF TUESDAY
MORNING THOUGH INTENSITY SHOULD BE KNOCKED DOWN LARGELY DUE TO
INVERSIONS FALLING BLO 4KFT. OVERALL...TOTAL SNOW ACCUMS FM THIS
EVENING THROUGH EARLY TUESDAY AFTN COULD NEAR 6 INCHES IN SPOTS OVR
HIGHER TERRAIN FM HURON MOUNTAINS TO ISHPEMING/NEGAUNEE AND SKANDIA
AREAS AND INTO WESTERN ALGER COUNTY FM DEERTON TO CHATHAM. 12 HR
SNOW AMOUNTS ARE ONLY MARGINALLY SUFFICIENT FOR ADVY THOUGH AND
SINCE THERE IS NOT MUCH FOR ADDITIONAL HAZARDS /CONSIDERABLE BLSN
FOR EXAMPLE/ HAVE HELD OFF ON ISSUING ADVY ATTM. WILL LET DAYSHIFT
TAKE ONE MORE LOOK AT DETAILS AND PUT HEADLINE UP IF NEEDED. NORTH
WINDS BACK MORE NORTHWEST BY LATE TUESDAY AFTN...SHIFTING
DIMINISHING SNOW SHOWERS ACROSS MUCH OF ALGER COUNTY. AWAY FM
LK EFFECT TUESDAY...MAIN ISSUE WILL BE RETURN TO WINTER WITH
TEMPERATURES IN THE TEENS/20S AND WIND CHILL READINGS IN THE
SINGLE DIGITS ABOVE ZERO FOR MUCH OF THE DAY. BASICALLY THAT IS
FAIRLY TYPICAL FOR THIS TIME OF YEAR...BUT GIVEN THE RECENT WARMTH
IT WILL DEFINITELY FEEL ON THE CHILLY SIDE.
.LONG TERM /TUE NIGHT THRU SUN/...
TUE NIGHT...SHRTWV RDG/SFC HI PRES WL DOMINATE. WITH MOCLR SKIES...
LGT WINDS...AND PWAT AS LO AS 0.10-0.15 INCH OR 40-50 PCT OF
NORMAL...EXPECT TEMPS OVER THE INTERIOR SRN TIER TO DIP AOB THE LO
END OF GUIDANCE. AS THE SFC RDG SINKS SLOWLY TO THE S THRU THE
NGT...A STRONGER W WIND WITH H925 WINDS UP TO 30 KTS WL INFLUENCE
AREAS NEAR LK SUP AND LIMIT THE DIURNAL TEMP FALL THERE.
WED...CWA WL BE UNDER STRENGTHENING WLY FLOW/H925 WINDS UP TO 35 KTS
BTWN HI PRES RDG SINKING TOWARD THE OH RIVER VALLEY AND ANOTHER LO
PRES/ATTENDANT COLD FNT TRACKING ACRS NRN ONTARIO ASSOCIATED WITH
SHRTWV WITHIN DEEPENING UPR TROF OVER HUDSON BAY. WITH DRY
AIRMASS/PWAT ARND 0.15 INCH LINGERING...EXPECT A MOSUNNY DAY. H85
TEMPS ARE PROGGED TO REBOUND TO ARND -5C...SO THE DAY WL BE WARMER.
BUT GUSTY W WIND WL MAKE THE AIR FEEL COLDER DESPITE SLOWLY INCRSG
SOLAR ANGLE.
WED NIGHT...COLD FNT ASSOCIATED WITH DEEPENING UPR TROF CENTERED
NEAR HUDSON BAY IS FCST TO DROP INTO NRN LK SUP BY 12Z THU. LACK OF
ANY MSTR INFLOW/DRY NATURE OF ANTECEDENT AIRMASS ARGUES FOR A DRY
FCST WITH LTL IN THE WAY OF PRE-FRONTAL CLD COVER AS WELL...BUT DID
INTRODUCE SOME SCHC POPS OVER THE N HALF OF LK SUP OVERNGT TO MARK
ARRIVAL OF THIS FNT. ALTHOUGH PWAT IS FCST TO REMAIN LO ARND 0.15
INCH...STEADY W WIND WL LIMIT THE DIURNAL FALL OF TEMP.
EXTENDED...MODELS NOW IN GOOD AGREEMENT FOR THU SHOWING A SHARP COLD
FROPA WITH ONLY A WEAK SFC LO RUNNING ALONG THIS BNDRY...IN CONTRAST
TO SOME PAST MODEL RUNS THAT DEPICTED A DEEPER LO. WITH DRY AIRMASS
PRECEDING THE FROPA...WENT NO HIER THAN CHC POPS EVEN NEAR LK SUP.
INFUSION OF MUCH COLDER AIR BEHIND THIS FROPA WITH 00Z GFS SHOWING
H85 TEMPS FALLING AS LO AS -25C AND INVRN BASE ARND 5K FT WL RESULT
IN SOME LES...MOST PREVALENT IN AREAS FAVORED BY FCST NNW FLOW THRU
FRI. TENDED TO GO HIER THAN MODEL CONSENSUS POPS IN THESE FAVORED
AREAS GIVEN TENDENCY FOR MODELS TO UNDERDO LES. THEN AS ARCTIC HI
PRES DRIFTS SEWD TOWARD THE UPR MIDWEST ON SAT...BACKING FLOW TO
MORE W WL SHIFT THE LES INTO AREAS FAVORED BY THAT FLOW. LINGERING
LES SHOULD DIMINISH/END ON SUN AS UPR TROF LIFTS OUT/FLOW TURNS MORE
ACYC WITH HI PRES DRIFTING INTO THE OH RIVER VALLEY. NEAR NORMAL
TEMPS ON THU WL SINK AOB NORMAL THU NGT THRU SAT AS ARCTIC AIRMASS
INVADES THE UPR LKS. TEMPS WL REBOUND ON SUN WITH BLDG UPR RDG INTO
THE GRT LKS/RETURN LLVL SW FLOW OF WARMER AIR TO THE N OF SFC HI IN
THE OH VALLEY.
&&
.AVIATION /FOR THE 12Z TAF ISSUANCE/...
COLD FRONT OVER ONTARIO DROPS ACROSS ALL TAF SITES TODAY. BASED ON
UPSTREAM TRENDS EXPECT VFR CIGS FOR A COUPLE HOURS INITIALLY FOLLOWED
BY CIGS LOWERING BLO 2KFT WITH SOME FLURRIES. WILD CARD THIS MORNING
IS BATCH OF LOW-LEVEL MOISTURE SEEN ON SATELLITE FM WEST OF THUNDER
BAY ONTARIO TOWARD SAULT STE MARIE. RECENTLY HAVE BEEN SOME HINTS
THAT THIS COULD EXPAND OVER NORTHERN UPR MI BY MID-LATE MORNING.
HAVE PUT SOME MENTION OF SCT BLO 010 IN TAFS AT CMX AND SAW. AT
THIS POINT...HAVE LOW CONFIDENCE IN THIS TURNING INTO A LOW CIG THIS
MORNING IS LOW...BUT WILL BE SOMETHING TO MONITOR. LK EFFECT SHOULD
DEVELOP LATE TODAY INTO TONIGHT AT ALL THREE TAF SITES. EXPECT VSBY
REDUCTION IN SNOW SHOWERS AND SOME BLOWING SNOW...ESPECIALLY AT KIWD
AND KSAW WITH FAVORED NORTH TO NORTHEAST WINDS. IFR VSBY IS POSSIBLE
BUT THINK CIGS WILL REMAIN AOA 1KFT.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT W WINDS UP TO 30 KTS EARLY TODAY TO WEAKEN A BIT WITH THE
APPROACH OF A COLD FRONT BUT THEN VEER TO THE N BY THIS EVNG AND
CRANK BACK UP TO 30 KTS FOLLOWING A COLD FRONTAL PASSAGE. THERE MAY
BE SOME GALE FORCE GUSTS TO 35 KTS AS WELL SINCE THE ARRIVAL OF MUCH
COLDER AIR OVER THE RELATIVELY WARM LAKE WATERS ENHANCES MIXING.
HOISTED A HEAVY FREEZING SPRAY WARNING FOR MUCH OF CENTRAL LAKE SUP
WITH INVASION OF ARCTIC AIR/HIER WAVES FORECAST IN THIS AREA INTO
TUE MORNING. THESE AUSTERE CONDITIONS WILL IMPROVE ON TUE WITH THE
ARRIVAL OF A HI PRES RIDGE/LIGHTER WINDS IN THE AFTERNOON. LIGHT
WINDS ON TUE EVENING ASSOCIATED WITH THE PASSING SFC HI PRES RIDGE
WILL INCREASE UP TO 30 KTS BY WED MORNING AS PRES GRADIENT SHARPENS
ONCE THE HI SINKS TOWARD THE OH RIVER VALLEY. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KTS OVER THE E WITH LONGER FETCH OF CHILLY
AIR OVER THE RELATIVELY WARM LAKE WATERS ALLOWING FOR MORE MIXING.
ALTHOUGH WINDS MAY DIMINISH LATE WED NIGHT INTO THU FOR A TIME AS
ONLY A WEAK LO PRES CENTER MOVES JUST TO THE NE OF THE LAKE...
EXPECT A STRONGER NNW FLOW TO 30 KTS TO DEVELOP FOLLOWING A COLD
FRONTAL PASSAGE ON THU. THE COMBINATION OF THESE STRONG WINDS AND
THE ARRIVAL OF VERY COLD AIR MAY RESULT IN HEAVY FREEZING SPRAY OVER
PORTIONS OF THE LAKE THRU THU NIGHT. THE CLOSER APPROACH OF A HI
PRES RIDGE WILL BRING DIMINISHING WINDS BY FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS
EVENING TO 10 AM EST /9 AM CST/ TUESDAY FOR LSZ241>244-263-
264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLA
SHORT TERM...JLA
LONG TERM...KC
AVIATION...JLA
MARINE...KC
AREA FORECAST DISCUSSION
NWS TWIN CITIES/CHANHASSEN MN
527 AM CST MON FEB 6 2012
.UPDATED FOR 12Z AVIATION DISCUSSION BELOW...
.DISCUSSION...
STILL A COMPLICATED CLOUD TREND THIS MORNING. THERE DOES SEEM TO
BE A BIT STRONGER EASTWARD PUSH OF THE CLOUD EDGE WEST OF MSP PER
THE MORE WEST COMPONENT SEEN IN THE LOW LEVELS. A DIFFERENT STORY
OVER FAR SOUTHERN MN. THAT EDGE HAS A SLOW NORTHWARD DRIFT WHICH
MAY CONTINUE AND PROBABLY KEEP SOUTH CENTRAL MN AND PARTS OF
WEST CENTRAL WI IN THE CLOUDS THOUGH THE MORNING. THE HRRR HAS HAD
THE BEST TREND ON THE LOW CLOUDS SINCE YESTERDAY...SO WILL TRY TO
FOLLOW THIS IN THE VERY SHORT TERM. THIS WILL OBVIOUSLY HAVE
IMPLICATIONS ON THE HOURLY TEMP TRENDS.
THE ARCTIC FRONT IS WELL MARKED WITH THE CLOUDS EDGE PUSHING
SOUTH OVER SOUTHERN CANADA..WILL WORK INTO OUR NORTHERN AREAS
THIS AFTERNOON. WILL USE MORE OF A MODEL DIURNAL TEMP TREND TODAY
WITH HIGHS REACHED EARLY IN THE FAR NORTHWEST ALONG WITH THE CLOUD
ISSUES IN THE SOUTH. STILL A DECENT CHANCE OF 40S FOR HIGHS IN THE
SOUTH. SOME MINOR LIFT WITH THE FRONT TONIGHT...AND THERE IS A
HINT OF PV ADVECTION LATE TONIGHT OVER FAR SOUTHERN MN FROM THE
SYSTEM TO OUR SOUTHWEST. WILL KEEP THE FLURRIES IN THE FORECAST
TONIGHT AND TUESDAY MORNING WITH THE FRONT AND WAIT ON THE
POSSIBILITY OF A SLIGHT CHANCE POP IN THE FAR SOUTH. THERE IS A
MINOR RISK OF FREEZING DRIZZLE WITH LACK OF MID LEVEL MOISTURE
UNTIL TUESDAY MORNING...BUT WITH A TIMING AN LOCATION
ISSUE...WILL WAIT ON THAT AS WELL.
A STRONGER FRONT STILL FORECAST TO AFFECT THE AREA THURSDAY AND
FRIDAY AND THE ECMWF HAS COME AROUND A LITTLE MORE IN LINE TO THE
GFS/GEM WITH THE STRENGTH. STILL A FAIR AMOUNT OF UNCERTAINTY IN
THE GFS ENSEMBLE TEMPS STARTING FRIDAY AND CONTINUING INTO THE
WEEKEND. EVEN THOUGH THE ECMWF LOOKS COLD FOR FRIDAY...IT`S TREND
FOR A GLANCING BLOW IS STILL THERE WITH A FLATTENING OF THE RIDGE
OUT WEST DURING THE WEEKEND. OUR CURRENT BLENDED FORECAST FOR
FRIDAY TEMPS MAY BE A BIT HIGH BUT THAT CAN STILL BE ADDRESSED IN
THE NEXT DAY OR TWO.
&&
.AVIATION.../12Z TAF ISSUANCE/
AREA OF IFR/LIFR DRIFTING SLOWLY EAST ABOUT 7 KNOTS THIS MORNING.
SOME CONCERN IFR REDEVELOPING TO THE SOUTHWEST AND MAY AFFECT EAST
CENTRAL MN/WESTERN WI LATER THIS MORNING. WILL LEAVE SOME SCT LOW
CLOUDS IN THE EAST...WITH CLEARING AT KRNH BY 14Z OR SO. NOT VERY
CONFIDENT WITH CLEARING AT KEAU...BUT WILL CONTINUE TREND OF
PREVIOUS FORECAST OF AROUND 19Z. OTHER CONCERN IS COLD FRONT
DROPPING ACROSS THE REGION THIS AFTERNOON. SHOULD CLEAR MOST AREAS
BY 00Z. LOW CLOUDS CURRENTLY LAG THE FRONT...INTO SOUTHERN CANADA.
MAY SEE SOME DEVELOPMENT DURING THE MORNING CLOSER TO THE FRONT..SO
WILL CONTINUE TREND OF DEVELOPING MVFR CIGS WITH PASSAGE OF THE COLD
FRONT. SOME LOWER CLOUDS DEVELOPING INTO NORTHEAST MN NOW. LOOKS
LIKE THERE COULD BE A SHOT OF FLURRIES WITH THE LOWER CLOUDS...AND
MENTIONED THAT AT KRWF FOR NOW....MAINLY IN THE 02Z-08Z PERIOD. MAY
SEE SOME BREAKS DEVELOPING IN THE KAXN BY MORNING...BUT WILL KEEP
MVFR CEILINGS ELSEWHERE. SOUTHWEST TO WEST WINDS AHEAD OF
FRONT...BECOMING NORTHWEST TO NORTH AND A BIT GUSTY WITH
FROPA.
KMSP...LIFR CEILINGS CLEARED THE AIRPORT AND SHOULD REMAIN SO
THROUGH THE DAY. SOME SMALL CHANCE OF LOWER CLOUDS LIFTING CLOSE TO
THE AIRPORT FROM THE SOUTHWEST LATER THIS MORNING...BUT WILL LEAVE
SCT FOR NOW. EXPECT VSBYS TO CLEAR THROUGH 15Z AS WELL. COLD FRONT
SWEEPS INTO THE AREA AROUND 22Z...THEN MVFR CEILINGS MOVING IN ABOUT
01Z. MAY SEE SOME FLURRIES BUT NOT EXPECTED TO BE SIGNIFICANT SOME
LEFT THEM OUT FOR NOW. WILL KEEP MVFR IN THROUGH THE TAF PERIOD.
SOUTHWEST TO WEST WINDS LESS THAN 10 KNOTS BECOMING NORTHWEST AND
NORTH WITH FROPA...AND A BIT GUSTY INTO THE EVENING AS COLD ADVECTION
CONTINUES.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/DWE
AREA FORECAST DISCUSSION
NWS GLASGOW MT
416 AM MST MON FEB 6 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
REX BLOCK OVER THE W STATES/W CANADA CONTINUES...HOWEVER NE MT ON
THE W EDGE OF NNW FLOW AROUND THE LARGE HUDSON BAY UPPER LOW
COMPLEX. THIS HAS BEEN BRINGING COLDER AIR INTO OUR AREA...WHICH
STARTED LAST NIGHT...WHICH WILL CONTINUE TODAY...RESULTING IN
HIGHS 15F OR MORE COLDER THAN YESTERDAY. STRONGEST 850 MB WINDS OF
UP TO 30 KT IN OUR N THIS MORNING. WE WILL BE ALMOST DRY
ADIABATICALLY MIXED...AND ALMOST TO THIS LEVEL...SO A LITTLE BIT
WINDY THIS MORNING IN COLD ADVECTION PATTERN.
THE COLDER AIRMASS IS ASSOCIATED WITH A 1045 MB SURFACE HIGH
PRESSURE CENTERED ON NE AB/NW SK BORDER THAN WILL MOVE TO OUR NE
BORDER LATE TONIGHT AND TUE. THE AIRMASS WITH THIS IS MOIST IN
LOWER LEVELS...BUT NOT PARTICULARLY COLD FOR THIS TIME OF YEAR.
OBS INDICATE NARROW TEMP/DEW POINT SPREADS IN OUR FORECAST AREA
OVERNIGHT AND EARLY THIS MORN...AND SIGNS OF VISIBILITY
REDUCTION. THERE ARE ALSO AREAS OF MULTIPLE AND EXPANDING LOWER
CLOUD LAYERS APPROACHING FROM THE NW AND N. MODELS INDICATE THIS
EXPANSION AS WELL AS LOWERING CEILINGS WILL CONTINUE...WITH RUC
AND HRRR SEEMING TO DO THE BEST WITH IT. THUS EXPECT SOME HIGHER
ELEVATIONS WILL END UP WITH FOG FROM THIS. ENOUGH WIND TO KEEP
LOWER ELEVATION FOG MORE PATCHY AND LESS VISIBILITY REDUCTION.
WILL ISSUE A HAZRDOUS WEATHER OUTLOOK (HWO).
THIS OVERCAST/FOG WILL LIFT SOME THIS AFTERNOON...THEN CLEAR OUT
TONIGHT BEHIND THE PASSAGE OF AN UPPER TROUGH...AND AS THE SURFACE
HIGH PUSHES IN. COLDER PART OF THE AIRMASS IS TONIGHT AND TUE WITH
THICKNESSES DOWN TO 510 DM AND 850 MB TEMPS AS LOW AS -13C IN OUR
AREA. MODELS ARE IN GOOD AGREEMENT DURING THE ENTIRE PERIOD.
THE SURFACE HIGH MOVES SE OUT OF THE AREA WED...ALLOWING FOR THE
WARMING OF THE AIRMASS. IT LEAVES BEHIND RATHER WEAK SURFACE
PRESSURES THOUGH AND CONTINUED DRY AIRMASS. RESULT IS SUNNY AND
A LITTLE WARMER WED WITH WINDS ON THE LIGHT SIDE. MODELS ARE
QUITE A BIT SLOWER THAN YESTERDAY WITH THE APPROACH OF THE NEXT
COLD FRONT FROM THE N. SIMONSEN
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE EXTENDED BEGINS WITH A LARGE UPPER LOW OVER NORTHERN QUEBEC
PROVINCE... RIDGING OVER THE WEST COAST WITH ANOTHER UPPER LOW
OVER THE KAMCHATAN PENINSULA IN FAR EASTERN RUSSIA. THE WEST COAST
RIDGE EXTENDS WELL INTO THE ARCTIC PROVIDING DRY NORTHERLY FLOW
FOR NORTHEAST MONTANA. AS THE FORECAST MOVES INTO THE WEEKEND THE
UPPER LOW OVER QUEBEC WEAKENS AND LIFTS INTO GREENLAND AS THE
KAMCHATKAN LOW MOVES INTO THE WESTERN BERING SEA. THE UPPER LOWS
ACTION OF PULLING APART ALLOWS THE WEST COAST RIDGE TO BREAK DOWN.
THE RESULT IS A MORE ZONAL FLOW KEEPING THE WEATHER PATTERN IN THE
DRY AND ABOVE NORMAL RANGE. MONDAY AND TUESDAY A TROUGH OF LOW
PRESSURE IS FORECAST TO DIG INTO THE AREA BRINGING A SLIGHT
POSSIBLY OF PRECIPITATION.
MODEL CONFIDENCE IS FAIR TO ABOVE NORMAL AT THE START OF THE
EXTENDED THROUGH SATURDAY AT 12Z WHEN THE MODELS HANDLE AN UPPER
LOW MOVING ONSHORE IN CENTRAL CALIFORNIA VERY DIFFERENTLY. LIKE
THE EC HANDLING OF IT AS A WEAK TROUGH OVER THE GEM/S OVER
DEEPENING AND THE GFS/S SLOWER MOVEMENT. FOR DAY 6 THROUGH DAY 8
THE GFS AND EC ARE SIMILAR FOR FAIR MODEL CONFIDENCE...THE GEM HAS
GONE IN A DIFFERENT DIRECTION.
TEMPS/PRECIPITATION FOR THE EXTENDED DOES NOT APPEAR TO HAVE MUCH
CHANGE FROM THE PAST COUPLE OF WEEKS. NO MAJOR CHANGE EXPECTED IN
THE EXTENDED. PROTON
&&
.AVIATION...
MVFR HAS DEVELOPED IN SOME AREAS THIS MORNING. A LARGE MASS OF MID
LEVEL VFR CLOUDS HAS DEVELOPED AHEAD OF COLD FRONT ACROSS THE
CENTRAL PRAIRIE PROVINCES. OVER CENTRAL MONTANA A MVFR DECK OF
STRATUS HAS FORMED...HOWEVER WITH THE MID CLOUD MOVING DOWN DO
EXPECT IT TO LIFT IN VFR LEVELS. EARLY THIS MORNING DO EXPECT
POCKETS OF MVFR AND ISOLATED IFR CONDITIONS WITH RIVER VALLEY
FOG... AGAIN SHORT LIVED WITH THE MID CLOUDS MOVING DOWN. FOR THE
REST OF DAY INTO TONIGHT LOOK FOR VFR SKIES AND EASTERLY WINDS. PROTON
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
733 AM CST MON FEB 6 2012
.UPDATE...
TAKING A LOOK AT LATEST OBSERVATIONS AND WEB CAMS...DENSE FOG IS
NOT PREVALENT IN OUR WESTERN COUNTIES. DENSE FOG ADVISORIES WEST
OF OUR AREA WERE CANCELLED EARLIER...SO WILL GO AHEAD AND CLEAR
WESTERN PARTS OF THE DENSE FOG ADVISORY. THE KOAX 12Z SOUNDING
SHOWED WEST OR SOUTHWEST WINDS OF 10-14 KNOTS JUST OFF THE SURFACE
SO THIS SHOULD HELP WITH THE FOG. WILL KEEP ADVISORY UNTIL 16Z FOR
EXTREME EASTERN NEBRASKA AND SOUTHWEST IOWA....
MILLER
&&
.PREV DISCUSSION... /ISSUED 520 AM CST MON FEB 6 2012/
AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
LOW CLOUDS AND FOG WILL BE THE MAIN CONCERNS AT LEAST THROUGH THE
MORNING HOURS. LIFR CONDITIONS SHOULD CONTINUE AT KOMA THROUGH AT
LEAST MID MORNING BUT SLOWLY IMPROVE TO VFR BY MID/LATE AFTERNOON.
FARTHER WEST AT KLNK AND KOFK...THE FOG WILL BE MORE VARIABLE THIS
MORNING. 13 KM RUC MODEL AND HIGH RESOLUTION RAPID REFRESH MODEL
BOTH SEEMED TO HAVE SOMEWHAT OF A HANDLE ON THE LOW CLOUDS.
WEST/SOUTHWEST WINDS SHOULD ALLOW FOR MAINLY VFR CONDITIONS FROM
MID AFTERNOON INTO THE EVENING WITH WEST OR SOUTHWEST LOW LEVEL
WINDS. IFR VSBYS COULD REFORM THIS EVENING FOR A WHILE...BUT DID
NOT MENTION AT THIS TIME. OTHERWISE...A COLD FRONT WILL PUSH
SOUTHWARD ACROSS THE AREA TONIGHT...SHIFTING WINDS TO THE NORTH.
LOOK FOR MVFR CEILINGS TO DEVELOP BEHIND THE FRONT. THERE COULD
ALSO BE SOME LIGHT SNOW OR FREEZING DRIZZLE.
MILLER
PREV DISCUSSION... /ISSUED 308 AM CST MON FEB 6 2012/
DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE EXTENT OF STRATUS/FOG AND HOW MUCH
THIS CAN ERODE THROUGH THE DAY. FOCUS THEN SHIFTS TO INCOMING
COLD FRONT AND SMALL CHANCE OF PCPN TONIGHT INTO TUESDAY.
UPPER CLOSED LOW CURRENTLY OVER THE GREAT BASIN WILL OPEN AND
CONTINUE TO PUSH EAST TOWARD THE CENTRAL PLAINS TODAY WHILE A
SHORTWAVE TROF OVER SRN CANADA MOVES SOUTH INTO THE NRN PLAINS
TONIGHT. AT THE SFC...AREA OF HIGH PRESSURE IS CENTERED OVER THE
SOUTHERN PLAINS WITH CALM WINDS OVER THE ENTIRE CWA. DENSE FOG
FORMED EARLY LAST EVENING OVER SNOWPACK AND DO EXPECT FOG TO LIFT
BY MID-LATE MORNING. STRATUS DECK OVER THE EASTERN COUNTIES IS
EXPECTED TO HANG ON THRU MUCH OF THE MORNING AND PERHAPS EVEN
INTO THE AFTERNOON HOURS AS INDICATED BY LATEST HRRR MODEL RUNS.
WL EXTEND DENSE FOG ADVISORY UNTIL 16Z AS VISIBILITIES WL BE SLOW
TO IMPROVE. STRATUS IN ADDITION TO SNOWCOVER WL PLAY HAVOC ON HIGH
TEMPERATURES. HAVE FORECAST HIGHS NEAR OR JUST ABOVE FREEZING
TODAY.
CDFNT ASSOCIATED WITH SRN CANADIAN SHORTWAVE WL MOVE INTO THE REGION
EARLY THIS EVENING AS WEAKENING SHORTWAVE ENERGY FROM GREAT BASIN
LOW APPROACHES THE AREA. LIGHT PCPN STILL ON TRACK TO DEVELOP ACROSS
KS/MO AND INTO SERN NEB. FORECAST SOUNDINGS INDICATE THE POTENTIAL
FOR LIGHT FREEZING DRIZZLE INTITIALLY AND THEN A QUICK CHANGE TO
LIGHT SNOW IF NOT JUST FLURRIES. PERIOD OF FORCING IS BRIEF AND
ONLY EXPECT LIGHT SNOWFALL ACCUMULATIONS OF GENERALLY A TENTH OF
AN INCH OR SO LATE TONIGHT INTO TUESDAY MORNING.
DRY WEATHER IS EXPECTED THEREAFTER AS SFC HIGH PRESSURE MOVES
OVER THE REGION ON WEDNESDAY. A STRONG COLD FRONT WILL SURGE SOUTH
THROUGH THE AREA LATE THURSDAY. HAVE COOLED TEMPS SIGNIFICANTLY
OVER THE WEEKEND TO ACCOUNT FOR THIS SURGE OF COLD AIR.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR NEZ015-034-
045-052-053-067-068-090>093.
IA...DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR IAZ043-055-
056-069-079-080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS STATE COLLEGE PA
634 AM EST MON FEB 6 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN PARKED JUST SOUTH OF
PENNSYLVANIA TODAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH ACROSS
THE STATE TUESDAY NIGHT. A WEAK WAVE ON THE FRONT WILL THEN PASS
SOUTH OF THE REGION ON WEDNESDAY. A MORE SIGNIFICANT COLD FRONT
WILL LIKELY PUSH THROUGH THE REGION LATE FRIDAY...POTENTIALLY
DELIVERING A BRIEF SHOT OF ARCTIC AIR.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLEAR SKIES AND A CALM WIND ASSOC WITH SFC RIDGE HAS ALLOWED SOME
RADIATION FOG TO FORM ALONG THE MASON DIXON LINE. LATEST HRRR SFC
RH FIELDS SUGGEST IT WILL DISSIPATE BY ARND 13Z. UPSTREAM SATL
IMAGERY INDICATES A NEARLY CLOUDLESS DAY IS ON TAP FOR CENTRAL PA.
INCREASING WLY TO SWRLY FLOW AHEAD OF AN APPROACHING COLD FRONT TO
THE NORTH WILL DRAW A SURGE OF VERY MILD AIR INTO THE REGION
TODAY. UNDER SUNNY SKIES...TEMPS SHOULD REACH 45-50F OVER MOST OF
CENTRAL PA. BUFKIT SOUNDINGS INDICATE SWRLY WIND GUSTS ARND 20KTS
OVR THE NORTH BY AFTN...WITH A LIGHTER BREEZE OVR SOUTHERN PA.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
PREFRONTAL AIR MASS WILL REMAIN MILD TONIGHT...BUT MCLEAR SKIES
AND A DIMINISHING BREEZE SHOULD ALLOW TEMPS TO FALL BACK TO THE
M/U20S IN MOST LOCATIONS. APPROACH OF COLD FRONT COULD BRING
INCREASING CLOUDS TO THE N MTNS TOWARD DAWN. UPPER LVL SHORTWAVE
LIFTING EAST FROM THE OHIO VALLEY WILL TRACK ALONG THE MASON DIXON
LINE TONIGHT. HOWEVER...ALL MDL DATA INDICATING NOT ENOUGH
MOISTURE PRESENT TO EVEN PRODUCE CLOUDINESS ACROSS SOUTHERN PA.
COLD FRONT WILL SAG SLOWLY SOUTHWARD ACROSS THE STATE ON TUESDAY.
HOWEVER...LACK OF SIG LG SCALE FORCING OR MOISTURE WILL RESULT IN A
DRY FROPA FOR MOST OF THE AREA. STRATO-CU AND SCT FLURRIES ARE
LIKELY TO FOLLOW THE FRONTAL PASSAGE ACROSS THE NORTH...WHILE
SOUTHERN PA SQUEAKS OUT ANOTHER MSUNNY AND MILD DAY. MAX TEMPS
SHOULD RANGE FROM THE M30S N MTNS...TO U40S LOWER SUSQ VALLEY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS COLD FRONT SAGS SOUTH OF THE MASON DIXON LINE WED...MDLS TRACK
SHORTWAVE AND ASSOC WEAK SFC WAVE SOUTH OF PA. DESPITE LIMITED
MOISTURE...MDL DATA INDICATES THIS WILL BE A FAIRLY VIGOROUS
SHORTWAVE WITH THE POTENTIAL TO PRODUCE A PERIOD OF LGT SNOW
WEDNESDAY. TIMING OF SHORTWAVE UNCERTAIN...WITH GFS/GEFS FASTER
THAN ECMWF. HOWEVER...HAVE INCREASED POPS IN THE 06Z WED-06Z THU
TIME FRAME ACROSS ALL OF CENTRAL/SOUTHERN PA. THE LAUREL HIGHLANDS
APPEAR MOST LIKELY TO RECEIVE A COUPLE INCHES OF SNOW FROM THIS
SYSTEM...DUE TO OROGRAPHIC ENHANCEMENT. FURTHER EAST...RELATIVELY
MILD SFC TEMPS WILL BE A LIMITING FACTOR FOR ANY ACCUMS ACROSS THE
LOWER SUSQ VALLEY...ESP DURING THE DAYLIGHT HRS.
SUNNY AND MILD WX APPEARS LIKELY TO RETURN THURSDAY...AS RIDGE OF
HIGH PRESSURE BUILDS OVR THE REGION. FCST UNCERTAINTY RAMPS UP A
BIT 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 FRI NIGHT...FOLLOWED
BY A SEASONABLY COLD/DRY WEEKEND. A COUPLE STRONGER/SLOWER GEFS
MEMBERS...WITH POSSIBLE E COAST CYCLOGENESIS...REMAIN UNLIKELY
OUTLIERS ATTM.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A RIDGE OF HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS CENTRAL
PENNSYLVANIA TODAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH ACROSS
THE STATE TUESDAY NIGHT.
BRIEF BOUT OF MVFR CIGS AT KBFD-KIPT EARLY ALONG PERIPHERY OF
BUILDING RIDGE...ALONG WITH SCT MVFR VSBY IN THE SE EARLY THIS
MORNING. BUT CONDITIONS IMPROVE QUICKLY...LEAVING A NEARLY
CLOUDLESS VFR DAY FROM LATE MORNING INTO TONIGHT. WINDS TODAY WILL
INCREASE FROM THE SW...SUSTAINED AT AROUND 10 MPH WITH GUSTS TO 20
MPH...AHEAD OF AN APPROACHING COLD FRONT. THE FRONT SLIPS INTO
NORTHERN PA LATE TONIGHT...LIKELY BRINGING MVFR CIGS INTO KBFD
AFTER 06Z TUE.
OUTLOOK...
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS WITH SHSN.
THU-FRI...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
601 AM EST MON FEB 6 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN PARKED JUST SOUTH OF
PENNSYLVANIA TODAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH ACROSS
THE STATE TUESDAY NIGHT. A WEAK WAVE ON THE FRONT WILL THEN PASS
SOUTH OF THE REGION ON WEDNESDAY. A MORE SIGNIFICANT COLD FRONT
WILL LIKELY PUSH THROUGH THE REGION LATE FRIDAY...POTENTIALLY
DELIVERING A BRIEF SHOT OF ARCTIC AIR.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
CLEAR SKIES AND A CALM WIND ASSOC WITH SFC RIDGE HAS ALLOWED SOME
RADIATION FOG TO FORM ALONG THE MASON DIXON LINE. LATEST HRRR SFC
RH FIELDS SUGGEST IT WILL DISSIPATE BY ARND 13Z. UPSTREAM SATL
IMAGERY INDICATES A NEARLY CLOUDLESS DAY IS ON TAP FOR CENTRAL PA.
INCREASING WLY TO SWRLY FLOW AHEAD OF AN APPROACHING COLD FRONT TO
THE NORTH WILL DRAW A SURGE OF VERY MILD AIR INTO THE REGION
TODAY. UNDER SUNNY SKIES...TEMPS SHOULD REACH 45-50F OVER MOST OF
CENTRAL PA. BUFKIT SOUNDINGS INDICATE SWRLY WIND GUSTS ARND 20KTS
OVR THE NORTH BY AFTN...WITH A LIGHTER BREEZE OVR SOUTHERN PA.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
PREFRONTAL AIR MASS WILL REMAIN MILD MONDAY NIGHT...BUT MCLEAR
SKIES AND A DIMINISHING BREEZE SHOULD ALLOW TEMPS TO FALL BACK TO
THE M/U20S IN MOST LOCATIONS. APPROACH OF COLD FRONT COULD BRING
INCREASING CLOUDS TO THE N MTNS TOWARD DAWN. UPPER LVL SHORTWAVE
LIFTING EAST FROM THE OHIO VALLEY WILL TRACK ALONG THE MASON DIXON
LINE TONIGHT. HOWEVER...ALL MDL DATA INDICATING NOT ENOUGH
MOISTURE PRESENT TO EVEN PRODUCE CLOUDINESS ACROSS SOUTHERN PA.
COLD FRONT WILL SAG SLOWLY SOUTHWARD ACROSS THE STATE ON TUESDAY.
HOWEVER...LACK OF SIG LG SCALE FORCING OR MOISTURE WILL RESULT IN A
DRY FROPA FOR MOST OF THE AREA. STRATO-CU AND SCT FLURRIES ARE
LIKELY TO FOLLOW THE FRONTAL PASSAGE ACROSS THE NORTH...WHILE
SOUTHERN PA SQUEAKS OUT ANOTHER MSUNNY AND MILD DAY. MAX TEMPS
SHOULD RANGE FROM THE M30S N MTNS...TO U40S LOWER SUSQ VALLEY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS COLD FRONT SAGS SOUTH OF THE MASON DIXON LINE WED...MDLS TRACK
SHORTWAVE AND ASSOC WEAK SFC WAVE SOUTH OF PA. DESPITE LIMITED
MOISTURE...MDL DATA INDICATES THIS WILL BE A FAIRLY VIGOROUS
SHORTWAVE WITH THE POTENTIAL TO PRODUCE A PERIOD OF LGT SNOW
WEDNESDAY. TIMING OF SHORTWAVE UNCERTAIN...WITH GFS/GEFS FASTER
THAN ECMWF. HOWEVER...HAVE INCREASED POPS IN THE 06Z WED-06Z THU
TIME FRAME ACROSS ALL OF CENTRAL/SOUTHERN PA. THE LAUREL HIGHLANDS
APPEAR MOST LIKELY TO RECEIVE A COUPLE INCHES OF SNOW FROM THIS
SYSTEM...DUE TO OROGRAPHIC ENHANCEMENT. FURTHER EAST...RELATIVELY
MILD SFC TEMPS WILL BE A LIMITING FACTOR FOR ANY ACCUMS ACROSS THE
LOWER SUSQ VALLEY...ESP DURING THE DAYLIGHT HRS.
SUNNY AND MILD WX APPEARS LIKELY TO RETURN THURSDAY...AS RIDGE OF
HIGH PRESSURE BUILDS OVR THE REGION. FCST UNCERTAINTY RAMPS UP A
BIT 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 FRI NIGHT...FOLLOWED
BY A SEASONABLY COLD/DRY WEEKEND. A COUPLE STRONGER/SLOWER GEFS
MEMBERS...WITH POSSIBLE E COAST CYCLOGENESIS...REMAIN UNLIKELY
OUTLIERS ATTM.
&&
.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A RIDGE OF HIGH PRESSURE WILL DOMINATE THE WEATHER ACROSS CENTRAL
PENNSYLVANIA TODAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH ACROSS
THE STATE TUESDAY NIGHT.
BRIEF BOUT OF MVFR CIGS AT KBFD-KIPT EARLY ALONG PERIPHERY OF
BUILDING RIDGE...ALONG WITH SCT MVFR VSBY IN THE SE EARLY THIS
MORNING. BUT CONDITIONS IMPROVE QUICKLY...LEAVING A NEARLY
CLOUDLESS VFR DAY FROM LATE MORNING INTO TONIGHT. WINDS TODAY WILL
INCREASE FROM THE SW...SUSTAINED AT AROUND 10 MPH WITH GUSTS TO 20
MPH...AHEAD OF AN APPROACHING COLD FRONT. THE FRONT SLIPS INTO
NORTHERN PA LATE TONIGHT...LIKELY BRINGING MVFR CIGS INTO KBFD
AFTER 06Z TUE.
OUTLOOK...
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS WITH SHSN.
THU-FRI...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
536 AM EST MON FEB 6 2012
.SYNOPSIS...
A RIDGE OF HIGH PRESSURE WILL REMAIN PARKED JUST SOUTH OF
PENNSYLVANIA TODAY AND TUESDAY. A COLD FRONT WILL SAG SOUTH ACROSS
THE STATE TUESDAY NIGHT. A WEAK WAVE ON THE FRONT WILL THEN PASS
SOUTH OF THE REGION ON WEDNESDAY. A MORE SIGNIFICANT COLD FRONT
WILL LIKELY PUSH THROUGH THE REGION LATE FRIDAY...POTENTIALLY
DELIVERING A BRIEF SHOT OF ARCTIC AIR.
&&
.NEAR TERM /UNTIL 7 AM THIS MORNING/...
CLEAR SKIES AND A CALM WIND ASSOC WITH SFC RIDGE HAS ALLOWED SOME
RADIATION FOG TO FORM ALONG THE MASON DIXON LINE. LATEST HRRR SFC
RH FIELDS SUGGEST IT WILL DISSIPATE BY ARND 13Z. UPSTREAM SATL
IMAGERY INDICATES A NEARLY CLOUDLESS DAY IS ON TAP FOR CENTRAL PA.
INCREASING WLY TO SWRLY FLOW AHEAD OF AN APPROACHING COLD FRONT TO
THE NORTH WILL DRAW A SURGE OF VERY MILD AIR INTO THE REGION
TODAY. UNDER SUNNY SKIES...TEMPS SHOULD REACH 45-50F OVER MOST OF
CENTRAL PA. BUFKIT SOUNDINGS INDICATE SWRLY WIND GUSTS ARND 20KTS
OVR THE NORTH BY AFTN...WITH A LIGHTER BREEZE OVR SOUTHERN PA.
&&
.SHORT TERM /7 AM THIS MORNING THROUGH 6 PM TUESDAY/...
PREFRONTAL AIR MASS WILL REMAIN MILD MONDAY NIGHT...BUT MCLEAR
SKIES AND A DIMINISHING BREEZE SHOULD ALLOW TEMPS TO FALL BACK TO
THE M/U20S IN MOST LOCATIONS. APPROACH OF COLD FRONT COULD BRING
INCREASING CLOUDS TO THE N MTNS TOWARD DAWN. UPPER LVL SHORTWAVE
LIFTING EAST FROM THE OHIO VALLEY WILL TRACK ALONG THE MASON DIXON
LINE TONIGHT. HOWEVER...ALL MDL DATA INDICATING NOT ENOUGH
MOISTURE PRESENT TO EVEN PRODUCE CLOUDINESS ACROSS SOUTHERN PA.
COLD FRONT WILL SAG SLOWLY SOUTHWARD ACROSS THE STATE ON TUESDAY.
HOWEVER...LACK OF SIG LG SCALE FORCING OR MOISTURE WILL RESULT IN A
DRY FROPA FOR MOST OF THE AREA. STRATO-CU AND SCT FLURRIES ARE
LIKELY TO FOLLOW THE FRONTAL PASSAGE ACROSS THE NORTH...WHILE
SOUTHERN PA SQUEAKS OUT ANOTHER MSUNNY AND MILD DAY. MAX TEMPS
SHOULD RANGE FROM THE M30S N MTNS...TO U40S LOWER SUSQ VALLEY.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
AS COLD FRONT SAGS SOUTH OF THE MASON DIXON LINE WED...MDLS TRACK
SHORTWAVE AND ASSOC WEAK SFC WAVE SOUTH OF PA. DESPITE LIMITED
MOISTURE...MDL DATA INDICATES THIS WILL BE A FAIRLY VIGOROUS
SHORTWAVE WITH THE POTENTIAL TO PRODUCE A PERIOD OF LGT SNOW
WEDNESDAY. TIMING OF SHORTWAVE UNCERTAIN...WITH GFS/GEFS FASTER
THAN ECMWF. HOWEVER...HAVE INCREASED POPS IN THE 06Z WED-06Z THU
TIME FRAME ACROSS ALL OF CENTRAL/SOUTHERN PA. THE LAUREL HIGHLANDS
APPEAR MOST LIKELY TO RECEIVE A COUPLE INCHES OF SNOW FROM THIS
SYSTEM...DUE TO OROGRAPHIC ENHANCEMENT. FURTHER EAST...RELATIVELY
MILD SFC TEMPS WILL BE A LIMITING FACTOR FOR ANY ACCUMS ACROSS THE
LOWER SUSQ VALLEY...ESP DURING THE DAYLIGHT HRS.
SUNNY AND MILD WX APPEARS LIKELY TO RETURN THURSDAY...AS RIDGE OF
HIGH PRESSURE BUILDS OVR THE REGION. FCST UNCERTAINTY RAMPS UP A
BIT 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 FRI NIGHT...FOLLOWED
BY A SEASONABLY COLD/DRY WEEKEND. A COUPLE STRONGER/SLOWER GEFS
MEMBERS...WITH POSSIBLE E COAST CYCLOGENESIS...REMAIN UNLIKELY
OUTLIERS ATTM.
&&
.AVIATION /10Z MONDAY THROUGH FRIDAY/...
A RIDGE OF HIGH PRESSURE WILL CONTINUE TO BUILD ACROSS
PENNSYLVANIA. DRY AIR ADVECTION WILL ALLOW FOR VFR CIGS AND VSBYS
ACROSS THE REGION. THE ONLY CHANCE...ALBEIT LOW...FOR MVFR CIGS
WILL BE ALONG THE NY/PA BORDER AT BFD. ELSEWHERE VFR CONDITIONS
AND LIGHT WINDS WILL DOMINATE THROUGH MONDAY NIGHT.
OUTLOOK...
TUE...MVFR POSS NW HALF. VFR SE.
WED...MVFR POSS WITH SHSN.
THU-FRI...VFR.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...FITZGERALD
NEAR TERM...FITZGERALD
SHORT TERM...FITZGERALD
LONG TERM...FITZGERALD
AVIATION...CERU/RXR
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
550 AM CST MON FEB 6 2012
.SHORT TERM...UPDATE
444 AM CST MON FEB 6 2012
HAVE MADE A QUICK UPDATE TO THE FORECAST AS SOME FLURRIES HAVE
BEEN REPORTED ACROSS THE AREA. THESE FLURRIES SHOULD END LATER
THIS MORNING AS TEMPERATURES WARM AND THE STRATUS DECK THINS OUT.
ALSO...A FEW MORE RUNS OF THE HRRR HAVE COME IN AND CONTINUE TO
KEEP THE CLOUDS IN THIS AFTERNOON...SO HAVE BOOSTED THE CLOUDINESS
A BIT MORE.
PREVIOUS AFD...
ONCE AGAIN WE ARE LEFT WITH A STRATUS DECK TO CONTEND WITH TODAY
WHICH WILL LIKELY HOLD TEMPERATURES BACK A BIT BEFORE A COLD FRONT
COMES THROUGH LATE THIS AFTERNOON AND EVENING.
A CUT OFF MID LEVEL LOW CONTINUES TO SPIN ACROSS THE CENTRAL
ROCKIES AS THE POLAR VORTEX BEGINS ITS DESCENT THROUGH EASTERN
CANADA. AT THE SURFACE...A RIDGE OF HIGH PRESSURE HAS DROPPED TO
THE SOUTHERN PLAINS WHILE A COLD FRONT IS PUSHING SOUTH ACROSS
ONTARIO AND THE DAKOTAS. MEANWHILE...A LOAN CLUSTER OF STRATUS
REMAINS TRAPPED UNDER AN INVERSION AROUND 950MB AND COVERS ALL OF
IOWA...THE WESTERN TWO THIRDS OF WISCONSIN AND THE EASTERN THIRD
OF MINNESOTA. THE 06.00Z MPX RAOB SHOWS THAT THIS LAYER OF STRATUS
IS ABOUT 200FT THICK...WHICH SHOULD BE THIN ENOUGH FOR SOME EXTRA
WIND TURBULENCE AND WARMING SURFACE TEMPERATURES TO POKE SOME
HOLES IN IT. THIS HAS NOT BEEN THE CASE OVERNIGHT DESPITE THE
INCREASING SURFACE WINDS AS THE STRATUS REMAINS A UNIFIED LAYER.
AS HAS BEEN THE CASE NOW FOR THE PAST 4 DAYS AND WHAT SEEMS THE
REST OF THIS WINTER...THE FORECAST FOR TODAY RESTS SOLELY ON WHAT
THIS THIN LAYER OF STRATUS DECIDES TO DO. IF THE STRATUS LINGERS
THROUGH THE DAY...HIGH TEMPERATURES WILL REMAIN IN THE LOW TO MID
30S. HOWEVER...IF SKIES CLEAR OUT AND BECOME SUNNY...HIGHS WILL
LIKELY REACH THE MID 40S. THE 06.00Z TO 06.05Z HRRR CEILING
PROJECTIONS HAVE ALL HAD A PRETTY GOOD HANDLE ON THE CURRENT
STRATUS FIELD AND HAVE BEEN FAIRLY CONSISTENT WITH ITS FORECAST OF
KEEPING THE STRATUS IN TACT THROUGH THE MORNING AND EARLY
AFTERNOON. THE 06.05Z HRRR RUN DID SHOW SOME HOLES STARTING TO POP
UP IN THE EARLY AFTERNOON...WHICH SEEMS PLAUSIBLE GIVEN THE
SHALLOW CLOUD DEPTH AND BETTER MIXING DUE TO AN INCREASING LOW
LEVEL PRESSURE GRADIENT AND WINDS. THEREFORE...HAVE KEPT
TEMPERATURES DOWN THROUGH THE MORNING WITH THE CLOUD COVER
EXPECTED TO AT LEAST HOLD ON UNTIL LUNCHTIME WITH A QUICK JUMP IN
TEMPERATURES THIS AFTERNOON AS HOLES START TO DEVELOP. WOULD NOT
BE SURPRISED TO SEE A FEW HIGHER TEMPERATURES CROP UP THIS
AFTERNOON...BUT CONFIDENCE IS JUST NOT HIGH ENOUGH AT THIS POINT
TO HAVE MID TO UPPER 40S IN THE FORECAST.
THE COLD FRONT ALONG THE US/CANADIAN BORDER THEN WILL ENTER THE
NORTHERN PORTION OF THE FORECAST AREA LATE THIS AFTERNOON AND PASS
THROUGH THE SOUTHERN PORTION OF THE FORECAST AREA BY MIDNIGHT
TONIGHT. SOME POST-FRONTAL FLURRIES LOOK POSSIBLE AS THE
TEMPERATURES IN THE LOW LEVEL CLOUD LAYER DROP TOWARD -10C
TONIGHT. THE 06.00Z NAM/GFS/GEM ALL HAVE SOME SPOTTY QPF THAT
SHOWS UP TONIGHT WHICH IS LIKELY A RESULT OF A SLIGHTLY DEEPER
DENDRITIC GROWTH ZONE THAT TRIES TO DEVELOP BETWEEN 900-750MB. THE
ONLY FORCING WITH THIS SYSTEM IS WITH SOME WEAKLY SLOPED
FRONTOGENESIS WITH THE MID LEVEL TROUGH LAGGING FAR BEHIND.
THUS...AM NOT TOO HIGH ON THE CHANCES FOR GETTING AN ACCUMULATING
SNOW OUT OF THIS FEATURE.
BEYOND THIS IT WILL JUST BE A QUESTION OF WHEN SKIES CLEAR OUT AS
A RIDGE OF HIGH PRESSURE SETS UP ACROSS THE PLAINS AND GREAT
LAKES. THIS RIDGE WILL DROP TEMPERATURES DOWN TO SEASONAL LEVELS GOING
INTO MID WEEK WITH THE CLEARING LIKELY TAKING PLACE ON WEDNESDAY.
.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
257 AM CST MON FEB 6 2012
THE MAIN FOCUS IN THE LONG TERM CONTINUES TO BE WITH WHEN A COLD
FRONT WILL DROP DOWN AND HOW COLD WILL IT GET LATE IN THE WEEK
AND WEEKEND. IT APPEARS THAT THE 06.00Z GFS AND ECMWF HAVE
FINALLY COME TO A COMPROMISE WITH BRINGING A NORTHEAST TO
SOUTHWEST ORIENTATED COLD FRONT THROUGH THE REGION THURSDAY
AFTERNOON AND EVENING WITH NO PRECIPITATION OCCURRING IN THE
REGION. TEMPERATURES WILL COOL TO BELOW NORMAL WITH 850MB
TEMPERATURES DROPPING TO -20C FOR A PERIOD THURSDAY NIGHT INTO AT
LEAST FRIDAY. THE 06.00Z ECMWF IS A BIT FASTER WITH BRINGING
WARMER AIR BACK IN AT THE LOW LEVELS ON SATURDAY ALREADY WHILE THE
06.00Z GFS HOLDS ONTO THE COLDER AIR FOR LONGER. THUS...HAVE GONE
WITH THE COLDER TEMPERATURES THURSDAY THROUGH SATURDAY WITH A
WARMING TREND SUNDAY.
&&
.AVIATION...TODAY AND TONIGHT
550 AM CST MON FEB 6 2012
STRATUS WILL PERSIST THROUGH MIDDAY TODAY AT THE TAF SITES
PRODUCING LIFR CONDITIONS AT KRST AND IFR CONDITIONS AT KLSE. PLAN
ON CLOUD BASES IN THE 200 TO 400 FT RANGE THROUGH 18Z TODAY AT
KRST...AND 700 TO 900 FT AT KLSE THROUGH 19Z. GUIDANCE IS
SUGGESTING THE OVERCAST STRATUS WILL BECOME SCATTERED THIS
AFTERNOON AHEAD OF A COLD FRONT ADVANCING SOUTHEAST FROM CENTRAL
MINNESOTA THROUGH NORTHERN WISCONSIN. LOOK FOR A FEW BREAKS IN THE
CLOUDS THIS AFTERNOON WITH A SHORT WINDOW OF VFR
CONDITIONS...MAINLY AFTER 19Z. MVFR STRATUS WILL MOVE BACK INTO THE
TAF SITES LATE THIS AFTERNOON INTO EARLY THIS EVENING AS THE COLD
FRONT MOVES INTO THE AREA. PLAN ON CLOUD BASES IN THE THE 1000 TO
1500 FT RANGE. NAM FORECAST SOUNDINGS ARE INDICATING THE POTENTIAL
FOR LIGHT FREEZING DRIZZLE THIS EVENING AS THE FRONT MOVES
IN...WITH NO ICE CRYSTALS ALOFT IN THE 03Z TO 08Z TIMEFRAME. THE
GFS ON THE OTHER HAND...SHOWS ICE ALOFT WITH FLURRIES DEVELOPING
ALONG AND BEHIND THE FRONT. CONFIDENCE LOW ON FREEZING DRIZZLE
THIS EVENING SO HAVE NOT INCLUDED IT IN THE TAFS AT THIS TIME.
WILL HAVE TO KEEP A CLOSE WATCH ON THE NEXT SET OF MODELS RUNS AND
OBSERVATIONS UPSTREAM THROUGH THE DAY. HAVE DECIDED TO MAINTAIN
FLURRIES AT BOTH TAF SITES STARTING AT 00Z AT KRST AND AT 01Z AT
KLSE. PLAN ON MVFR CONDITIONS THROUGH THE NIGHT. WINDS WILL VEER TO
THE NORTHWEST LATE THIS AFTERNOON AS THE FRONT MOVES IN...WITH
WIND SPEEDS OF 7 TO 14 KTS EXPECTED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
257 AM CST MON FEB 6 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....WETENKAMP
AREA FORECAST DISCUSSION...UPDATED
NWS LA CROSSE WI
444 AM CST MON FEB 6 2012
.SHORT TERM...UPDATE
444 AM CST MON FEB 6 2012
HAVE MADE A QUICK UPDATE TO THE FORECAST AS SOME FLURRIES HAVE
BEEN REPORTED ACROSS THE AREA. THESE FLURRIES SHOULD END LATER
THIS MORNING AS TEMPERATURES WARM AND THE STRATUS DECK THINS OUT.
ALSO...A FEW MORE RUNS OF THE HRRR HAVE COME IN AND CONTINUE TO
KEEP THE CLOUDS IN THIS AFTERNOON...SO HAVE BOOSTED THE CLOUDINESS
A BIT MORE.
PREVIOUS AFD...
ONCE AGAIN WE ARE LEFT WITH A STRATUS DECK TO CONTEND WITH TODAY
WHICH WILL LIKELY HOLD TEMPERATURES BACK A BIT BEFORE A COLD FRONT
COMES THROUGH LATE THIS AFTERNOON AND EVENING.
A CUT OFF MID LEVEL LOW CONTINUES TO SPIN ACROSS THE CENTRAL
ROCKIES AS THE POLAR VORTEX BEGINS ITS DESCENT THROUGH EASTERN
CANADA. AT THE SURFACE...A RIDGE OF HIGH PRESSURE HAS DROPPED TO
THE SOUTHERN PLAINS WHILE A COLD FRONT IS PUSHING SOUTH ACROSS
ONTARIO AND THE DAKOTAS. MEANWHILE...A LOAN CLUSTER OF STRATUS
REMAINS TRAPPED UNDER AN INVERSION AROUND 950MB AND COVERS ALL OF
IOWA...THE WESTERN TWO THIRDS OF WISCONSIN AND THE EASTERN THIRD
OF MINNESOTA. THE 06.00Z MPX RAOB SHOWS THAT THIS LAYER OF STRATUS
IS ABOUT 200FT THICK...WHICH SHOULD BE THIN ENOUGH FOR SOME EXTRA
WIND TURBULENCE AND WARMING SURFACE TEMPERATURES TO POKE SOME
HOLES IN IT. THIS HAS NOT BEEN THE CASE OVERNIGHT DESPITE THE
INCREASING SURFACE WINDS AS THE STRATUS REMAINS A UNIFIED LAYER.
AS HAS BEEN THE CASE NOW FOR THE PAST 4 DAYS AND WHAT SEEMS THE
REST OF THIS WINTER...THE FORECAST FOR TODAY RESTS SOLELY ON WHAT
THIS THIN LAYER OF STRATUS DECIDES TO DO. IF THE STRATUS LINGERS
THROUGH THE DAY...HIGH TEMPERATURES WILL REMAIN IN THE LOW TO MID
30S. HOWEVER...IF SKIES CLEAR OUT AND BECOME SUNNY...HIGHS WILL
LIKELY REACH THE MID 40S. THE 06.00Z TO 06.05Z HRRR CEILING
PROJECTIONS HAVE ALL HAD A PRETTY GOOD HANDLE ON THE CURRENT
STRATUS FIELD AND HAVE BEEN FAIRLY CONSISTENT WITH ITS FORECAST OF
KEEPING THE STRATUS IN TACT THROUGH THE MORNING AND EARLY
AFTERNOON. THE 06.05Z HRRR RUN DID SHOW SOME HOLES STARTING TO POP
UP IN THE EARLY AFTERNOON...WHICH SEEMS PLAUSIBLE GIVEN THE
SHALLOW CLOUD DEPTH AND BETTER MIXING DUE TO AN INCREASING LOW
LEVEL PRESSURE GRADIENT AND WINDS. THEREFORE...HAVE KEPT
TEMPERATURES DOWN THROUGH THE MORNING WITH THE CLOUD COVER
EXPECTED TO AT LEAST HOLD ON UNTIL LUNCHTIME WITH A QUICK JUMP IN
TEMPERATURES THIS AFTERNOON AS HOLES START TO DEVELOP. WOULD NOT
BE SURPRISED TO SEE A FEW HIGHER TEMPERATURES CROP UP THIS
AFTERNOON...BUT CONFIDENCE IS JUST NOT HIGH ENOUGH AT THIS POINT
TO HAVE MID TO UPPER 40S IN THE FORECAST.
THE COLD FRONT ALONG THE US/CANADIAN BORDER THEN WILL ENTER THE
NORTHERN PORTION OF THE FORECAST AREA LATE THIS AFTERNOON AND PASS
THROUGH THE SOUTHERN PORTION OF THE FORECAST AREA BY MIDNIGHT
TONIGHT. SOME POST-FRONTAL FLURRIES LOOK POSSIBLE AS THE
TEMPERATURES IN THE LOW LEVEL CLOUD LAYER DROP TOWARD -10C
TONIGHT. THE 06.00Z NAM/GFS/GEM ALL HAVE SOME SPOTTY QPF THAT
SHOWS UP TONIGHT WHICH IS LIKELY A RESULT OF A SLIGHTLY DEEPER
DENDRITIC GROWTH ZONE THAT TRIES TO DEVELOP BETWEEN 900-750MB. THE
ONLY FORCING WITH THIS SYSTEM IS WITH SOME WEAKLY SLOPED
FRONTOGENESIS WITH THE MID LEVEL TROUGH LAGGING FAR BEHIND.
THUS...AM NOT TOO HIGH ON THE CHANCES FOR GETTING AN ACCUMULATING
SNOW OUT OF THIS FEATURE.
BEYOND THIS IT WILL JUST BE A QUESTION OF WHEN SKIES CLEAR OUT AS
A RIDGE OF HIGH PRESSURE SETS UP ACROSS THE PLAINS AND GREAT
LAKES. THIS RIDGE WILL DROP TEMPERATURES DOWN TO SEASONAL LEVELS GOING
INTO MID WEEK WITH THE CLEARING LIKELY TAKING PLACE ON WEDNESDAY.
.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
257 AM CST MON FEB 6 2012
THE MAIN FOCUS IN THE LONG TERM CONTINUES TO BE WITH WHEN A COLD
FRONT WILL DROP DOWN AND HOW COLD WILL IT GET LATE IN THE WEEK
AND WEEKEND. IT APPEARS THAT THE 06.00Z GFS AND ECMWF HAVE
FINALLY COME TO A COMPROMISE WITH BRINGING A NORTHEAST TO
SOUTHWEST ORIENTATED COLD FRONT THROUGH THE REGION THURSDAY
AFTERNOON AND EVENING WITH NO PRECIPITATION OCCURRING IN THE
REGION. TEMPERATURES WILL COOL TO BELOW NORMAL WITH 850MB
TEMPERATURES DROPPING TO -20C FOR A PERIOD THURSDAY NIGHT INTO AT
LEAST FRIDAY. THE 06.00Z ECMWF IS A BIT FASTER WITH BRINGING
WARMER AIR BACK IN AT THE LOW LEVELS ON SATURDAY ALREADY WHILE THE
06.00Z GFS HOLDS ONTO THE COLDER AIR FOR LONGER. THUS...HAVE GONE
WITH THE COLDER TEMPERATURES THURSDAY THROUGH SATURDAY WITH A
WARMING TREND SUNDAY.
&&
.AVIATION...THROUGH 06Z TUESDAY
1135 PM CST SUN FEB 5 2012
AT 05Z A LARGE AREA OF STRATUS WAS OVER THE UPPER MISSISSIPPI
RIVER VALLEY REGION. THE BACK EDGE WAS PUSHING INTO SOUTH CENTRAL
MINNESOTA. HOWEVER...MORE STRATUS WAS LIFTING NORTHWARD OUT OF
IOWA INTO SOUTHWEST MINNESOTA. MODELS HAVE STRUGGLED OVER THE PAST
FEW DAYS WITH THE TREND TO CLEAR IT OUT TOO QUICKLY DURING THE DAY
AND THE 06.00Z NAM AGAIN DOING THE SAME THING. 06.02Z HRRR SHOWING
STRATUS TO REMAIN IN PLACE THROUGH AT LEAST 18Z AND THIS GOING
WITH A MORE PESSIMISTIC FORECAST. CAN NOT RULE OUT SOME BRIEF
CLEARING AFTER 18Z-20Z MONDAY...BUT IT WILL BE SHORT LIVED AS A
COLD FRONT WILL DROP SOUTHWARD THROUGH THE AREA...WITH ALL THE
MODELS SHOWING POST FRONTAL STRATUS TO MOVE BACK IN AROUND 00Z.
THUS WILL KEEP THE IFR CONDITIONS GOING THROUGH MUCH OF THE DAY
WITH A BRIEF BREAK THIS AFTERNOON BEFORE MVFR POST FRONTAL
CEILINGS MOVE IN.
NEXT QUESTION IS ON ANY POST FRONTAL PRECIPITATION CHANCES. 06.00Z
NAM AND GFS BOTH SHOWING SOME LIGHT PRECIPITATION. NAM IS THE
EARLIEST IN THE EVENING...WHILE THE GFS WOULD SUGGEST AFTER
MIDNIGHT. ONE CONCERN OF ANYTHING FALLING IN THE EVENING...IS THE
POTENTIAL LACK OF ICE CRYSTALS IN THE CLOUDS WHICH COULD RESULT IN
SOME PATCHY FREEZING DRIZZLE RATHER THAN FLURRIES. FOR NOW WILL
JUST MENTION FLURRIES...BUT THIS WILL HAVE TO BE MONITORED.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
257 AM CST MON FEB 6 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM...HALBACH
AVIATION...RABERDING
AREA FORECAST DISCUSSION
NWS LINCOLN IL
252 PM CST MON FEB 6 2012
.DISCUSSION...
ISSUED 252 PM CST MON FEB 6 2012
A LARGE AREA OF STATUS/FOG ACROSS CENTRAL AND SOUTHEAST ILLINOIS
HAS GRADUALLY BEEN ERODING THIS AFTERNOON. THIS CLOUDINESS IS
SANDWICHED BETWEEN A SURFACE RIDGE OF HIGH PRESSURE EXTENDING
ALONG THE OHIO VALLEY AND COLD FRONT SINKING INTO THE GREAT
LAKES/UPPER MIDWEST. MAIN FORECAST CONCERN TODAY REVOLVES AROUND
THE DISPOSITION AND/OR POSSIBLE REFORMATION OF THIS CLOUD DECK
TONIGHT...AS WELL AS PRECIPITATION CHANCES WITH THE APPROACHING
COLD FRONT. THE REMAINDER OF THE FORECAST PERIOD APPEARS RATHER
QUIET AT THE MOMENT...THOUGH A BRIEF COLD SNAP IS STILL EXPECTED
FOR THE WEEKEND.
12Z MODELS STILL IN GOOD AGREEMENT WITH THE BIG PICTURE OVER THE
NEXT FEW DAYS...ALTHOUGH THE SYNOPTIC MODELS REMAIN UNAWARE OF THE
STRATUS/FOG ACROSS THE AREA. THE STRATUS/FOG CONTINUES TO BE
PICKED UP BY SOME MESOSCALE MODELS...BUT THEY ARE NOW OVERPLAYING
THE AREAL EXTENT TO SOME DEGREE. WILL CONTINUE TO HANDLE THE
STRATUS/FOG WITH A COMBINATION OF EXTRAPOLATION AND CONCEPTUAL
MODELS...WITH A MODEL BLEND A GOOD BET OTHERWISE.
SHORT TERM...TONIGHT THROUGH THURSDAY...EXPECT STRATUS/FOG TO
CONTINUE TO ERODE OVER THE NEXT COUPLE OF HOURS UNTIL DIURNAL
HEATING IS LOST. WHAT HAPPENS NEXT IS A BIG QUESTION. WHILE THE
PESKY CLOUD DECK EXPANDED CONSIDERABLY AFTER SUNSET FOR MOST OF
LAST NIGHT DESPITE SHRINKING YESTERDAY...FEEL THIS SHOULD BE LESS
OF A PROBLEM TONIGHT. WEST SOUTHWEST FLOW AHEAD OF THE APPROACHING
FRONT WILL BE STRONGER THAN WAS SEEN LAST NIGHT...HELPING TO KEEP
THE BOUNDARY LAYER MIXED UP A LITTLE BETTER. IN ADDITION...ACROSS
IOWA...WHERE THE CLOUDS WERE MOST PERSISTENT UNDER A SIMILAR WEST
SOUTHWEST FLOW YESTERDAY/LAST NIGHT...THE FLOW WAS COMING OFF A
SNOW FIELD EXTENDING SOUTHWEST INTO NEBRASKA AND KANSAS. WE DO NOT
HAVE THIS POTENTIAL SOURCE OF ADDITIONAL LOW LEVEL MOISTURE
LOCALLY. SO...DO NOT EXPECT TO HIT THE LOW CLOUDS/FOG AS HARD AS
LAST NIGHT. NEVERTHELESS...MID/HIGH LEVEL CLOUDS WILL INCREASE
FROM NORTHWEST TO SOUTHEAST OVERNIGHT AS THE FRONT DRAWS CLOSER.
THE COLD FONT WILL SINK THROUGH THE FORECAST AREA ON TUESDAY...
THOUGH IT IS EXPECTED TO BE MOISTURE STARVED AND A MINIMAL
PRECIPITATION PRODUCER. THE BEST CHANCES FOR PRECIPITATION WILL
OCCUR TUESDAY AFTERNOON/NIGHT ACROSS SOUTHERN SECTIONS OF THE
FORECAST AREA AS AN UPPER LOW OVER THE ROCKIES OPENS UP AND TRACKS
EAST ALONG THE FRONTAL BOUNDARY. FORECAST SOUNDINGS SUGGEST THAT
MOST OF THE PRECIPITATION WILL BE POST FRONTAL WHEN TEMPERATURES
HAVE COOLED SUFFICIENTLY TO FALL AS SNOW. THERE MAY BE A BRIEF
RAIN/SNOW MIX ACROSS SOUTHEAST ILLINOIS. DO NOT EXPECT MUCH MORE
THAN A DUSTING WITH THE SNOW THAT DOES FALL.
SOME FLURRIES MAY LINGER INTO WEDNESDAY...BUT THE WEATHER
WEDNESDAY INTO THURSDAY WILL BE MOSTLY QUIET AS HIGH PRESSURE
BUILDS INTO THE AREA. CHILLY POST FRONTAL TEMPERATURES ON WEDNESDAY
WILL MODERATE A BIT THURSDAY AS RETURN FLOW DEVELOPS ON THE BACK
SIDE OF THE HIGH.
LONG TERM...FRIDAY THROUGH MONDAY...MODELS/ENSEMBLES STILL SUGGEST
SIGNIFICANT UPPER TROFFING AND POOLING OF COLD AIR ACROSS EASTERN
CANADA BY THE END OF THE WEEK. HOWEVER...CONSIDERABLE MODEL SPREAD
AND RUN-TO-RUN VARIABILITY PERSIST WITH THE EXTENT OF COLD AIR
THAT SINKS INTO THE AREA BEHIND A COLD FRONT ON FRIDAY. THIS FRONT
WILL ALSO BE MOISTURE STARVED AND PRODUCE LITTLE IF ANY
PRECIPITATION. DESPITE THE UNCERTAINTY WITH HOW COLD THE WEEKEND
WILL BE...THE MODELS AGREE THAT ANY COLD INTRUSION WILL BE SHORT
LIVED DUE TO A PROGRESSIVE UPPER LEVEL PATTERN. A MODEL CONSENSUS
ALSO EXISTS THAT OUR NEXT WEATHER SYSTEM WILL ARRIVE AROUND
MONDAY...THOUGH AGREEMENT IN THE DETAILS IS NOT VERY GOOD. WILL
ONLY CARRY A LOW CHANCE OF RAIN/SNOW MONDAY UNTIL THE DETAILS CAN
BE IRONED OUT A LITTLE BETTER.
BAK
&&
.AVIATION...
ISSUED 1214 PM CST MON FEB 6 2012
MODELS STILL HAVE NO REFLECTION OF THE LLVL MOISTURE TRAPPED OVER
MUCH OF THE MIDWEST. CONDITIONS IMPROVING...THOUGH SLOWLY. CONCERN
WILL BE SAME AS YESTERDAY...VIS IMPROVING...CIGS REMAIN OR BREAK
ONLY SLIGHTLY WITH THE AFTERNOON HOURS...ONLY TO RETURN AGAIN
TONIGHT. HAVE FOLLOWED THAT TREND...REDUCING CMI AND BMI TO LIFR
AFTER MIDNIGHT...WITH THE DEEPEST MOISTURE AND LEAVING REMAINING
TERMINALS IN THE IFR CAT WITH CIGS. FORECAST IS MORE OF A
PERSISTENCE FORECAST THAN A MODELED ONE...BUT THE HRRR IS THE ONLY
MODEL PICKING UP ON THE TREND...AND IT CONFIRMS THE CONTINUATION
OF THE LLVL RH.
HJS
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1219 PM CST MON FEB 6 2012
.DISCUSSION...
ISSUED 1043 AM CST MON FEB 6 2012
PLENTY OF LLVL MOISTURE TRAPPED NEAR THE SFC RESULTING IN A
CONTINUED LOW CLOUD/LOW VISIBILITY SITUATION FOR MUCH OF CENTRAL
ILLINOIS. PERSISTENT STRATUS SHIELD MOVING IN FROM UPPER MIDWEST
LAST NIGHT WILL BE SLOW TO LEAVE...RESULTING IN A RATHER GRAY DAY.
HAVE UPDATED THE FORECAST TO KNOCK BACK THE TEMPS
CONSIDERABLY...AT LEAST NORTH OF INTERSTATE 70. ALONG AND SOUTH OF
INTERSTATE 70 IS ALREADY SEEING A LITTLE MORE SUNSHINE.
ELSEWHERE...MAX TEMPS NEED TO BE LOWER. HAVE FRESHENED THE GRIDS A
BIT...ISSUE REMAINS WITH THE PERSISTENCE OF THE FOG ADVISORY...AND
HOW QUICKLY THE STRATUS/FOG WILL ERODE WITH MINIMAL DAYTIME
HEATING. WILL BE POSTPONING AN UPDATE TO THE ZONES UNTIL CLOSER TO
NOON.
&&
.AVIATION...
ISSUED 1214 PM CST MON FEB 6 2012
MODELS STILL HAVE NO REFLECTION OF THE LLVL MOISTURE TRAPPED OVER
MUCH OF THE MIDWEST. CONDITIONS IMPROVING...THOUGH SLOWLY. CONCERN
WILL BE SAME AS YESTERDAY...VIS IMPROVING...CIGS REMAIN OR BREAK
ONLY SLIGHTLY WITH THE AFTERNOON HOURS...ONLY TO RETURN AGAIN
TONIGHT. HAVE FOLLOWED THAT TREND...REDUCING CMI AND BMI TO LIFR
AFTER MIDNIGHT...WITH THE DEEPEST MOISTURE AND LEAVING REMAINING
TERMINALS IN THE IFR CAT WITH CIGS. FORECAST IS MORE OF A
PERSISTENCE FORECAST THAN A MODELED ONE...BUT THE HRRR IS THE ONLY
MODEL PICKING UP ON THE TREND...AND IT CONFIRMS THE CONTINUATION
OF THE LLVL RH.
HJS
&&
.PREV DISCUSSION...
ISSUED 235 AM CST MON FEB 6 2012
SHORT TERM...TODAY THROUGH WEDNESDAY...
MAIN HEADACHES THE LAST FEW HOURS HAVE BEEN WITH LOW CLOUDS AND
DENSE FREEZING FOG DEVELOPMENT. STRATUS DECK HAS BEEN ADVANCING
SOUTHEASTWARD AND HAD REACHED THE I-55 CORRIDOR AT 2 AM.
VISIBILITIES ALONG THIS EDGE QUICKLY TANKED AND THE 1/4 MILE
VISIBILITY EXTENDS NORTHWEST FOR ABOUT 60 MILES FROM THE LEADING
EDGE. HAVE ALSO BEEN SEEING SOME PATCHIER DENSE FOG DEVELOPING
OVER THE EASTERN CWA...IN AREAS WHERE SKIES HAVE BEEN MAINLY
CLEAR. MODEL GUIDANCE WITH THIS STRATUS DECK OVER THE LAST DAY OR
TWO HAS BEEN QUITE POOR. THE HRRR APPEARS TO DO THE BEST JOB...BUT
ONLY GOES OUT ABOUT 12 HOURS. THE LATEST RAPID-REFRESH ALSO SEEMS
TO BE OK...AND SPREADS THE CLOUDS OVER MOST OF THE REMAINING CWA
EARLY THIS MORNING AND KEEPS LOWER VISIBILITIES GOING THROUGH
ABOUT 9-10 AM...WITH FOG LIFTING FROM THE NORTHWEST. WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FOR AREAS BETWEEN THE ILLINOIS
RIVER AND I-70 FOR THIS MORNING. TEMPERATURES TODAY WILL BE VERY
TRICKY DEPENDING ON HOW FAST THE CLOUDS FINALLY BREAK UP THIS
AFTERNOON...IF THEY INDEED DO SO. HAVE UNDERCUT GUIDANCE
TEMPERATURES UNDERNEATH BY A FEW DEGREES UNDERNEATH THE STRATUS
DECK...BUT ANY BREAKUP TOO EARLY IN THE DAY WILL CAUSE SIGNIFICANT
ERRORS IN THE HIGH TEMPERATURE FORECAST.
THE OTHER FOCUS DURING THIS PERIOD WILL BE AS A SHORTWAVE...THE
REMNANTS OF A CUTOFF LOW CURRENTLY OVER THE CENTRAL ROCKIES...
INTERACTS WITH ANOTHER WAVE WHICH WILL SWEEP ACROSS THE GREAT
LAKES ON TUESDAY AND WEDNESDAY. STILL NOT A LOT OF MOISTURE
AVAILABILITY WITH THIS SYSTEM...WITH MOST OF THE MODEL GUIDANCE
SUPPORTING LOW CHANCE POPS ACROSS THE SOUTHERN HALF OF THE CWA.
MAY SEE SOME MINOR SNOW ACCUMULATIONS TUESDAY EVENING NEAR THE
I-72 CORRIDOR...DEPENDING ON HOW FAST SURFACE TEMPERATURES DROP
BEFORE THE PRECIPITATION EXITS.
LONG TERM...THURSDAY THROUGH SUNDAY...
MAIN FOCUS IN THIS PERIOD REMAINS WITH ARCTIC AIR MASS WHICH WILL
DROP INTO THE GREAT LAKES LATE IN THE WEEK. COLD FRONT PROGGED TO
MOVE ACROSS THE AREA EARLY FRIDAY MORNING...ALTHOUGH MOST OF THE
MOISTURE WILL BE CLOSER TO THE GREAT LAKES AND WILL GO WITH A DRY
FRONTAL PASSAGE HERE. HOWEVER...LATEST GFS/ECMWF BOTH BRING 850
MB TEMPERATURES AS LOW AS -17C INTO THE CWA BY SATURDAY MORNING...
WHICH WOULD KEEP MUCH OF THE CWA AT OR BELOW FREEZING ON
SATURDAY. AS WITH MOST OF THE COLD PERIODS THIS WINTER...ONLY
LOOKING AT ABOUT A 36-48 HOUR PERIOD WHERE IT WOULD ACTUALLY BE
CONSIDERED TO BE COLD...BEFORE TEMPERATURES QUICKLY RETURN TO NEAR
NORMAL.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
AREA FORECAST DISCUSSION
NWS LINCOLN IL
1048 AM CST MON FEB 6 2012
.DISCUSSION...
ISSUED 1043 AM CST MON FEB 6 2012
PLENTY OF LLVL MOISTURE TRAPPED NEAR THE SFC RESULTING IN A
CONTINUED LOW CLOUD/LOW VISIBILITY SITUATION FOR MUCH OF CENTRAL
ILLINOIS. PERSISTENT STRATUS SHIELD MOVING IN FROM UPPER MIDWEST
LAST NIGHT WILL BE SLOW TO LEAVE...RESULTING IN A RATHER GRAY DAY.
HAVE UPDATED THE FORECAST TO KNOCK BACK THE TEMPS
CONSIDERABLY...AT LEAST NORTH OF INTERSTATE 70. ALONG AND SOUTH OF
INTERSTATE 70 IS ALREADY SEEING A LITTLE MORE SUNSHINE.
ELSEWHERE...MAX TEMPS NEED TO BE LOWER. HAVE FRESHENED THE GRIDS A
BIT...ISSUE REMAINS WITH THE PERSISTENCE OF THE FOG ADVISORY...AND
HOW QUICKLY THE STRATUS/FOG WILL ERODE WITH MINIMAL DAYTIME
HEATING. WILL BE POSTPONING AN UPDATE TO THE ZONES UNTIL CLOSER TO
NOON.
HJS
&&
.AVIATION...
ISSUED 515 AM CST MON FEB 6 2012
DURATION OF VLIFR/LIFR CIGS AND VSBYS TODAY THE MAIN FORECAST
CHALLENGE. THE LOW STRATUS DECK THAT WAS OUT TO OUR NORTHWEST
STARTED TO INCREASE ITS SE MOVEMENT LAST EVENING AND HAS PUSHED
TO JUST NORTH OF THE I-70 CORRIDOR...AND EXTENDS WEST THRU THE
NORTHERN HALF OF MO INTO EXTREME EASTERN NEBRASKA. NOT MUCH
HOPE OF SEEING ANY SIGNIFICANT CLEARING TAKING PLACE TODAY
DESPITE BOUNDARY LAYER WINDS INCREASING OUT OF THE WEST AND
SOUTHWEST. WILL TAKE A MORE PESSIMISTIC OUTLOOK WITH RESPECT
TO THE CIGS AND VSBYS TODAY AND CONTINUE TO KEEP AT LEAST IFR
CIGS/VSBYS INTO THIS AFTERNOON. THE BIG QUESTION IS HOW QUICKLY
THAT WILL TRANSITION FROM VLIFR TO IFR. BASED ON THE HI-RES
RAPID REFRESH SOLUTION...WILL START TO SEE A GRADUAL IMPROVEMENT
IN CIGS AND VSBYS AFTR 16Z BUT CONTINUE WITH IFR/LIFR CIGS DURING
THE AFTN. REALLY DON`T SEE ANY MECHANISM TO DISPERSE THE CLOUDS
AND IMPROVE THE CIGS SIGNIFICANTLY UNTIL A COLD FRONT MOVES ACRS
THE AREA LATER TONIGHT OR EARLY TUESDAY MORNING.
SURFACE WINDS WILL TEND TO BACK MORE INTO A SOUTHWEST DIRECTION
TODAY AT 8 TO 13 KTS...AND VEER MORE INTO THE WEST AND THEN
NORTHWEST LATE IN THE FORECAST PERIOD AS THE COLD FRONT
APPROACHES.
SMITH
&&
.PREV DISCUSSION...
ISSUED 235 AM CST MON FEB 6 2012
SHORT TERM...TODAY THROUGH WEDNESDAY...
MAIN HEADACHES THE LAST FEW HOURS HAVE BEEN WITH LOW CLOUDS AND
DENSE FREEZING FOG DEVELOPMENT. STRATUS DECK HAS BEEN ADVANCING
SOUTHEASTWARD AND HAD REACHED THE I-55 CORRIDOR AT 2 AM.
VISIBILITIES ALONG THIS EDGE QUICKLY TANKED AND THE 1/4 MILE
VISIBILITY EXTENDS NORTHWEST FOR ABOUT 60 MILES FROM THE LEADING
EDGE. HAVE ALSO BEEN SEEING SOME PATCHIER DENSE FOG DEVELOPING
OVER THE EASTERN CWA...IN AREAS WHERE SKIES HAVE BEEN MAINLY
CLEAR. MODEL GUIDANCE WITH THIS STRATUS DECK OVER THE LAST DAY OR
TWO HAS BEEN QUITE POOR. THE HRRR APPEARS TO DO THE BEST JOB...BUT
ONLY GOES OUT ABOUT 12 HOURS. THE LATEST RAPID-REFRESH ALSO SEEMS
TO BE OK...AND SPREADS THE CLOUDS OVER MOST OF THE REMAINING CWA
EARLY THIS MORNING AND KEEPS LOWER VISIBILITIES GOING THROUGH
ABOUT 9-10 AM...WITH FOG LIFTING FROM THE NORTHWEST. WILL GO AHEAD
AND ISSUE A DENSE FOG ADVISORY FOR AREAS BETWEEN THE ILLINOIS
RIVER AND I-70 FOR THIS MORNING. TEMPERATURES TODAY WILL BE VERY
TRICKY DEPENDING ON HOW FAST THE CLOUDS FINALLY BREAK UP THIS
AFTERNOON...IF THEY INDEED DO SO. HAVE UNDERCUT GUIDANCE
TEMPERATURES UNDERNEATH BY A FEW DEGREES UNDERNEATH THE STRATUS
DECK...BUT ANY BREAKUP TOO EARLY IN THE DAY WILL CAUSE SIGNIFICANT
ERRORS IN THE HIGH TEMPERATURE FORECAST.
THE OTHER FOCUS DURING THIS PERIOD WILL BE AS A SHORTWAVE...THE
REMNANTS OF A CUTOFF LOW CURRENTLY OVER THE CENTRAL ROCKIES...
INTERACTS WITH ANOTHER WAVE WHICH WILL SWEEP ACROSS THE GREAT
LAKES ON TUESDAY AND WEDNESDAY. STILL NOT A LOT OF MOISTURE
AVAILABILITY WITH THIS SYSTEM...WITH MOST OF THE MODEL GUIDANCE
SUPPORTING LOW CHANCE POPS ACROSS THE SOUTHERN HALF OF THE CWA.
MAY SEE SOME MINOR SNOW ACCUMULATIONS TUESDAY EVENING NEAR THE
I-72 CORRIDOR...DEPENDING ON HOW FAST SURFACE TEMPERATURES DROP
BEFORE THE PRECIPITATION EXITS.
LONG TERM...THURSDAY THROUGH SUNDAY...
MAIN FOCUS IN THIS PERIOD REMAINS WITH ARCTIC AIR MASS WHICH WILL
DROP INTO THE GREAT LAKES LATE IN THE WEEK. COLD FRONT PROGGED TO
MOVE ACROSS THE AREA EARLY FRIDAY MORNING...ALTHOUGH MOST OF THE
MOISTURE WILL BE CLOSER TO THE GREAT LAKES AND WILL GO WITH A DRY
FRONTAL PASSAGE HERE. HOWEVER...LATEST GFS/ECMWF BOTH BRING 850
MB TEMPERATURES AS LOW AS -17C INTO THE CWA BY SATURDAY MORNING...
WHICH WOULD KEEP MUCH OF THE CWA AT OR BELOW FREEZING ON
SATURDAY. AS WITH MOST OF THE COLD PERIODS THIS WINTER...ONLY
LOOKING AT ABOUT A 36-48 HOUR PERIOD WHERE IT WOULD ACTUALLY BE
CONSIDERED TO BE COLD...BEFORE TEMPERATURES QUICKLY RETURN TO NEAR
NORMAL.
GEELHART
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR ILZ031-037-038-
041>057-061>063-066>068-071>073.
&&
$$
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
354 PM EST MON FEB 6 2012
.UPDATE...
THE AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL GIVE WAY TO AN UPPER WAVE TUESDAY NIGHT THAT
WILL BRING SMALL CHANCES FOR SNOW TO CENTRAL INDIANA INTO
WEDNESDAY MORNING. ANOTHER COUPLE OF WEAK WAVES WILL MOVE THROUGH
EARLY IN THE WEEKEND AND AGAIN ON MONDAY AND BRING MORE SMALL
CHANCES FOR PRECIPITATION. TEMPERATURES WILL ACTUALLY DROP TO NEAR
NORMAL FROM MIDWEEK THROUGH THE WEEKEND WITH BROAD TROUGHING OVER
THE EASTERN PART OF THE COUNTRY.
&&
.NEAR TERM /TONIGHT/...
WITH HIGH PRESSURE SUBSIDENCE OVER THE AREA AND A STRATUS DECK TO
THE WEST WITH WESTERLY LOW LEVEL FLOW OVERNIGHT THINK STRATUS WILL
ADVECT BACK INTO THE NORTHWEST AND OVERSPREAD THE NORTHWESTERN TWO
THIRDS OF THE AREA DURING THE OVERNIGHT HOURS SINCE THERE WILL BE
NOTHING TO STOP IT. WHILE LARGE SCALE MODELS DO NOT DO A GOOD JOB
DEPICTING THIS LOW LEVEL RH FIELDS AND SOUNDINGS FROM THE RUC SHOW
THIS POTENTIAL AND THE RUC DID A MUCH BETTER JOB HANDLING WHAT
HAPPENED THIS MORNING. COULD ALSO SEE SOME PATCHY FOG ACROSS THE
AREA. NOT SURE OF EXTENT OR SPECIFIC LOCATION OF FOG...BUT WITH
RECENT MORNINGS AND FORECAST SOUNDINGS WILL GO AHEAD AND PUT PATCHY
FOG EVERYWHERE. WITH THE INCREASE IN CLOUD COVER THAT THE GFS AND
NAM DON/T HAVE ALSO WENT WITH WARMER LOWS THAN GUIDANCE OVER ALL BUT
THE SOUTHEAST WHERE STRATUS MAY NOT REACH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
FORECAST FOCUS IS ON CLOUD COVER TUESDAY AND POPS WITH TUESDAY
NIGHT/WEDNESDAY SYSTEM. MODELS ARE IN DECENT AGREEMENT AND WILL USE
A CONSENSUS APPROACH FOR THE MOST PART.
AFOREMENTIONED STRATUS MAY ERODE SOME IN THE LATE MORNING TUESDAY BUT
WILL ALSO START TO SEE AN INCREASE IN CLOUDS AS THE NEXT UPPER WAVE
APPROACHES FROM THE NORTHWEST...SO NET RESULT SHOULD BE MOSTLY
CLOUDY SKIES TO EVEN CLOUDY SKIES IN THE NORTHWEST. WITH MORE CLOUD
COVER IN THE NORTH AND CENTRAL WILL ALSO DROP HIGHS THERE FROM
GUIDANCE. THE UPPER WAVE MOVING IN TUESDAY NIGHT PROVIDES ONLY WEAK
TO AT MOST MODERATE UPPER LEVEL FORCING AND THERE IS NOTHING ELSE
HELPING THIS SYSTEM...NO INSTABILITY...NO LOW LEVEL FORCING...AND
LITTLE MOISTURE. THE BEST FORCING STILL APPEARS TO BE MOVING THROUGH
BETWEEN 6 AND 12Z AND THUS KEPT LOW CHANCE POPS GOING THEN WITH
SLIGHT CHANCES FOR 6 HOURS ON EITHER SIDE. SOUNDINGS IN ALL BUT THE
SOUTH LOOK COLD ENOUGH FOR ALL SNOW. WILL START WITH A RAIN SNOW MIX
IN THE SOUTH BEFORE CHANGING OVER TO ALL SNOW. LITTLE TO NO
ACCUMULATION EXPECTED.
BY WEDNESDAY 18Z THE UPPER WAVE HAS MOVED OUT OF THE AREA AND
RIDGING IS MOVING BACK INTO THE AREA FROM THEN ON SO DRY WEATHER
FROM THAT POINT THROUGH THURSDAY. WENT COOLER THAN GUIDANCE
WEDNESDAY WITH COLD ADVECTION OCCURRING.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
OVERALL THE EXTENDED WILL BE A QUIET PERIOD. HOWEVER THERE ARE TWO
SYSTEMS THAT MAY GIVE LOW CHANCES OF PRECIP. ONE PERIOD IS FRIDAY
AFTERNOON AND NIGHT AS COLD FRONT MOVES THROUGH FRIDAY AFTERNOON
FOLLOWED BY AN UPPER TROUGH FRIDAY NIGHT AND SATURDAY. THE GFS STILL
HAS US DRY...BUT THE EUROPEAN AND CANADIAN AS WELL AS CONSALL GIVES
US LOW CHANCES OF PRECIPITATION. TEMPERATURES MAY BE WARM ENOUGH
FOR MIXED PRECIP ACROSS OUR SOUTH FRIDAY AFTERNOON. OTHERWISE...WILL
GO WITH A SLIGHT CHANCE OF SNOW SHOWERS.
THE UPPER TROUGH MOVES ON TO THE EAST OVER THE WEEKEND AND WARM
ADVECTION SETS UP BY MONDAY AHEAD OF THE NEXT SYSTEM. THE GFS
BARELY BRINGS PRECIP INTO OUR NORTHWEST BY 00Z TUESDAY AND THE
EUROPEAN IS EVEN SLOWER. WILL TRIM POPS A LITTLE...BUT KEEP LOW
CHANCES ACROSS OUR WEST BY LATE DAY 7. DID NOT MAKE ANY SIGNIFICANT
CHANGE TO ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 06/18Z TAF ISSUANCE/...
2030Z UPDATE...KIND AVIATION FORECAST PRETTY MUCH REPRESENTATIVE...ONLY
ADDED IN SOME FEW CU FOR THE NEXT HOURS BASED ON TRENDS. HOWEVER...KLAF
LOOKS TO REMAIN AT IFR FOR AT LEAST THE NEXT FEW HOURS AS THAT
STRATUS DECK HANGS ON A BIT LONGER. PREVIOUS DISCUSSION
FOLLOWS....
EASTERN EDGE OF STRATUS/FOG DECK NEAR KOKOMO TO KHUF LINE WILL START
ERODING THIS AFTERNOON AND BOTH KHUF AND KLAF TAFS WILL IMPROVE TO
VFR BY LATE AFTERNOON. FARTHER WEST THAT THIS STRATUS DECK WILL
REMAIN INTACT AND START SPREADING EASTWARD AGAIN DURING THE
OVERNIGHT HOURS. THE RUC SOUNDING INDICATES THIS OCCURRING
OVERNIGHT AT MOST TAF SITES. BUT THERE IS MORE UNCERTAINTY WHETHER
THIS STRATUS/FOG DECK REACHES KBMG. FOR NOW WILL PLAY IT THAT
WAY...BUT HAPPENING LATER TONIGHT. THUS ALL TAFS WILL BECOME IFR OR
LIFR DURING THE OVERNIGHT HOURS. BUFKIT IS SOMEWHAT NEUTRAL ON
WHETHER THIS WILL BE MOSTLY STRATUS OR FOG. BUT IN AREAS WHERE
STRATUS ADVECT IN...IT MAY KEEP VISIBILITIES FROM DROPPING TOO LOW.
ON TUESDAY...THERE MAY BE SOME IMPROVEMENT ACROSS THE SOUTHERN HALF
OF OUR REGION. A COLD FRONT WILL MOVE INTO OUR REGION LATE TUESDAY.
WINDS WILL BE WEST OR SOUTHWEST AT 6 TO 8 KNOTS THIS AFTERNOON AND
LESS THAN 5 KNOTS TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....JH
AVIATION...JH/SMF
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
332 PM EST MON FEB 6 2012
.UPDATE...
THE SYNOPSIS...NEAR TERM...SHORT TERM AND LONG TERM SECTIONS HAVE
BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL GIVE WAY TO AN UPPER WAVE TUESDAY NIGHT THAT
WILL BRING SMALL CHANCES FOR SNOW TO CENTRAL INDIANA INTO
WEDNESDAY MORNING. ANOTHER COUPLE OF WEAK WAVES WILL MOVE THROUGH
EARLY IN THE WEEKEND AND AGAIN ON MONDAY AND BRING MORE SMALL
CHANCES FOR PRECIPITATION. TEMPERATURES WILL ACTUALLY DROP TO NEAR
NORMAL FROM MIDWEEK THROUGH THE WEEKEND WITH BROAD TROUGHING OVER
THE EASTERN PART OF THE COUNTRY.
&&
.NEAR TERM /TONIGHT/...
WITH HIGH PRESSURE SUBSIDENCE OVER THE AREA AND A STRATUS DECK TO
THE WEST WITH WESTERLY LOW LEVEL FLOW OVERNIGHT THINK STRATUS WILL
ADVECT BACK INTO THE NORTHWEST AND OVERSPREAD THE NORTHWESTERN TWO
THIRDS OF THE AREA DURING THE OVERNIGHT HOURS SINCE THERE WILL BE
NOTHING TO STOP IT. WHILE LARGE SCALE MODELS DO NOT DO A GOOD JOB
DEPICTING THIS LOW LEVEL RH FIELDS AND SOUNDINGS FROM THE RUC SHOW
THIS POTENTIAL AND THE RUC DID A MUCH BETTER JOB HANDLING WHAT
HAPPENED THIS MORNING. COULD ALSO SEE SOME PATCHY FOG ACROSS THE
AREA. NOT SURE OF EXTENT OR SPECIFIC LOCATION OF FOG...BUT WITH
RECENT MORNINGS AND FORECAST SOUNDINGS WILL GO AHEAD AND PUT PATCHY
FOG EVERYWHERE. WITH THE INCREASE IN CLOUD COVER THAT THE GFS AND
NAM DON/T HAVE ALSO WENT WITH WARMER LOWS THAN GUIDANCE OVER ALL BUT
THE SOUTHEAST WHERE STRATUS MAY NOT REACH.
&&
.SHORT TERM /TUESDAY THROUGH THURSDAY/...
FORECAST FOCUS IS ON CLOUD COVER TUESDAY AND POPS WITH TUESDAY
NIGHT/WEDNESDAY SYSTEM. MODELS ARE IN DECENT AGREEMENT AND WILL USE
A CONSENSUS APPROACH FOR THE MOST PART.
AFOREMENTIONED STRATUS MAY ERODE SOME IN THE LATE MORNING TUESDAY BUT
WILL ALSO START TO SEE AN INCREASE IN CLOUDS AS THE NEXT UPPER WAVE
APPROACHES FROM THE NORTHWEST...SO NET RESULT SHOULD BE MOSTLY
CLOUDY SKIES TO EVEN CLOUDY SKIES IN THE NORTHWEST. WITH MORE CLOUD
COVER IN THE NORTH AND CENTRAL WILL ALSO DROP HIGHS THERE FROM
GUIDANCE. THE UPPER WAVE MOVING IN TUESDAY NIGHT PROVIDES ONLY WEAK
TO AT MOST MODERATE UPPER LEVEL FORCING AND THERE IS NOTHING ELSE
HELPING THIS SYSTEM...NO INSTABILITY...NO LOW LEVEL FORCING...AND
LITTLE MOISTURE. THE BEST FORCING STILL APPEARS TO BE MOVING THROUGH
BETWEEN 6 AND 12Z AND THUS KEPT LOW CHANCE POPS GOING THEN WITH
SLIGHT CHANCES FOR 6 HOURS ON EITHER SIDE. SOUNDINGS IN ALL BUT THE
SOUTH LOOK COLD ENOUGH FOR ALL SNOW. WILL START WITH A RAIN SNOW MIX
IN THE SOUTH BEFORE CHANGING OVER TO ALL SNOW. LITTLE TO NO
ACCUMULATION EXPECTED.
BY WEDNESDAY 18Z THE UPPER WAVE HAS MOVED OUT OF THE AREA AND
RIDGING IS MOVING BACK INTO THE AREA FROM THEN ON SO DRY WEATHER
FROM THAT POINT THROUGH THURSDAY. WENT COOLER THAN GUIDANCE
WEDNESDAY WITH COLD ADVECTION OCCURRING.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
OVERALL THE EXTENDED WILL BE A QUIET PERIOD. HOWEVER THERE ARE TWO
SYSTEMS THAT MAY GIVE LOW CHANCES OF PRECIP. ONE PERIOD IS FRIDAY
AFTERNOON AND NIGHT AS COLD FRONT MOVES THROUGH FRIDAY AFTERNOON
FOLLOWED BY AN UPPER TROUGH FRIDAY NIGHT AND SATURDAY. THE GFS STILL
HAS US DRY...BUT THE EUROPEAN AND CANADIAN AS WELL AS CONSALL GIVES
US LOW CHANCES OF PRECIPITATION. TEMPERATURES MAY BE WARM ENOUGH
FOR MIXED PRECIP ACROSS OUR SOUTH FRIDAY AFTERNOON. OTHERWISE...WILL
GO WITH A SLIGHT CHANCE OF SNOW SHOWERS.
THE UPPER TROUGH MOVES ON TO THE EAST OVER THE WEEKEND AND WARM
ADVECTION SETS UP BY MONDAY AHEAD OF THE NEXT SYSTEM. THE GFS
BARELY BRINGS PRECIP INTO OUR NORTHWEST BY 00Z TUESDAY AND THE
EUROPEAN IS EVEN SLOWER. WILL TRIM POPS A LITTLE...BUT KEEP LOW
CHANCES ACROSS OUR WEST BY LATE DAY 7. DID NOT MAKE ANY SIGNIFICANT
CHANGE TO ALL BLEND TEMPERATURES.
&&
.AVIATION /DISCUSSION FOR THE 06/18Z TAF ISSUANCE/...
EASTERN EDGE OF STRATUS/FOG DECK NEAR KOKOMO TO KHUF LINE WILL START
ERODING THIS AFTERNOON AND BOTH KHUF AND KLAF TAFS WILL IMPROVE TO
VFR BY LATE AFTERNOON. FARTHER WEST THAT THIS STRATUS DECK WILL
REMAIN INTACT AND START SPREADING EASTWARD AGAIN DURING THE
OVERNIGHT HOURS. THE RUC SOUNDING INDICATES THIS OCCURRING
OVERNIGHT AT MOST TAF SITES. BUT THERE IS MORE UNCERTAINTY WHETHER
THIS STRATUS/FOG DECK REACHES KBMG. FOR NOW WILL PLAY IT THAT
WAY...BUT HAPPENING LATER TONIGHT. THUS ALL TAFS WILL BECOME IFR OR
LIFR DURING THE OVERNIGHT HOURS. BUFKIT IS SOMEWHAT NEUTRAL ON
WHETHER THIS WILL BE MOSTLY STRATUS OR FOG. BUT IN AREAS WHERE
STRATUS ADVECT IN...IT MAY KEEP VISIBILITIES FROM DROPPING TOO LOW.
ON TUESDAY...THERE MAY BE SOME IMPROVEMENT ACROSS THE SOUTHERN HALF
OF OUR REGION. A COLD FRONT WILL MOVE INTO OUR REGION LATE TUESDAY.
WINDS WILL BE WEST OR SOUTHWEST AT 6 TO 8 KNOTS THIS AFTERNOON AND
LESS THAN 5 KNOTS TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...CP
NEAR TERM...CP
SHORT TERM...CP
LONG TERM....JH
AVIATION...JH
AREA FORECAST DISCUSSION
NWS INDIANAPOLIS IN
1207 PM AM EST MON FEB 6 2012
.UPDATE...
AVIATION SECTION HAS BEEN UPDATED BELOW.
&&
.SYNOPSIS...
HIGH PRESSURE WILL KEEP DRY MILD WEATHER ACROSS CENTRAL INDIANA
THROUGH TUESDAY. A SERIES OF WEAK UPPER LEVEL DISTURBANCES WILL
BRING THE CHANCE FOR LIGHT PRECIPITATION TUESDAY NIGHT AND
WEDNESDAY. HIGH PRESSURE WILL BRING A RETURN TO DRY WEATHER FOR LATE
WEEK AND INTO THE WEEKEND. THE EXPANSION OF A BROAD UPPER LEVEL
TROUGH WILL SIGNAL A SHIFT TO COLDER TEMPERATURES BY THE WEEKEND.
&&
.NEAR TERM /REST OF TODAY/...
FOG OVER THE NORTHWESTERN COUNTIES CONTINUES TO HANG IN THERE WITH
VISIBILITIES AT OR BELOW A QUARTER MILE AND TEMPERATURES RIGHT
AROUND THE FREEZING MARK...SO EXTENDED ADVISORY THROUGH 18Z. WITH
THINNING SEEN ON VISIBLE SATELLITE AND TEMPERATURES AT LEAST NOW
CLIMBING TO FREEZING THINK IMPROVEMENTS WILL BE SUFFICIENT BY 18Z
TO ALLOW END OF ADVISORY THEN. FOG AND LOW CLOUDS ARE INHIBITING
WARMING IN THE AFOREMENTIONED AREA AND THUS LOWERED TEMPERATURES
THERE FOR THE AFTERNOON...BUT ELSEWHERE THINK UPPER 40S TO AROUND
50 WILL BE ACHIEVABLE UNDER SUNNY SKIES.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
FORECAST CHALLENGES FOCUS ON PRECIP CHANCES TUESDAY NIGHT AND
WEDNESDAY AS A SERIES OF WEAK UPPER LEVEL DISTURBANCES PASS THROUGH
THE LOWER GREAT LAKES.
HIGH PRESSURE RIDGE WILL BRING ANOTHER TRANQUIL NIGHT WITH CLEAR
SKIES TONIGHT. THE RIDGE SHIFTS EAST TUESDAY WITH MID AND HIGH LEVEL
CLOUDS EXPANDING INTO THE REGION FROM THE NORTHWEST. CHANCES FOR
PRECIPITATION ARE LIKELY TO HOLD OFF UNTIL TUESDAY EVENING AS LEAD
SHORTWAVE ASSOCIATED WITHIN LARGER UPPER TROUGH ROTATES ACROSS THE
REGION. ISENTROPIC LIFT AND OVERALL FORCING REMAIN GENERALLY
WEAK...BUT DOES APPEAR ENOUGH MOISTURE PRESENT FOR LIGHT
PRECIPITATION. WHILE A LIGHT RAIN/SNOW MIX IS POSSIBLE OVER SOUTHERN
COUNTIES TUESDAY EVENING...LOW LEVEL THERMALS AND MODEL SOUNDINGS
SHOW PRECIPITATION AS ALL SNOW AFTER MIDNIGHT AS THE BOUNDARY LAYER
AND NEAR SURFACE TEMPS COOL. SHORTWAVE AXIS SWINGS ACROSS THE
FORECAST AREA BETWEEN 06-12Z WEDNESDAY WITH BEST FORCING ALOFT. THIS
LIKELY TO BE THE TIMEFRAME WHEN LIGHT SNOW IS MOST PREVALENT WITH
HIGHEST POPS. APPEARS THERE COULD BE A FEW TENTHS OF AN INCH
ACCUMULATION BY DAYBREAK WEDNESDAY.
SCATTERED LIGHT SNOW SHOWERS WILL PERSIST WEDNESDAY MORNING WITH A
GRADUAL DIMINISHING OF COVERAGE AS BETTER MOISTURE AND FORCING SHIFT
EAST THROUGH THE DAY. CLOUDS AND A FEW FLURRIES LIKELY TO LINGER
UNTIL THE MAIN UPPER TROUGH PASSES WEDNESDAY AFTERNOON. WILL HOLD
ONTO LOW CHANCE POPS ON WEDNESDAY WITH MODEL SOUNDINGS FAVORING ANY
PRECIP TO FALL IN THE FORM OF LIGHT SNOW. NOT ANTICIPATING ANY
ADDITIONAL LIGHT ACCUMS AT THIS POINT. UPPER TROUGH MOVES AWAY TO
THE EAST WEDNESDAY WITH ANOTHER SURGE OF DEEP SUBSIDENCE ADVECTING
INTO THE REGION AS HIGH PRESSURE REESTABLISHES. SKIES SHOULD CLEAR
QUICKLY SETTING THE STAGE FOR A CHILLY NIGHT.
TEMPS...GENERALLY LEANED TOWARDS COOLER METMOS GUIDANCE THROUGH THE
PERIOD...ESPECIALLY TUESDAY NIGHT AND WEDNESDAY WITH CLOUDS AND
PRECIP. COLDEST NIGHT WILL BE WEDNESDAY NIGHT AS LOWS FALL TO NEAR
20 DEGREES UNDER CLEAR SKIES.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
QUIET EXTENDED PERIOD FOR THE MOST PART...WITH THE ONLY EXCEPTION
BEING A VERY BROAD UPPER LEVEL TROUGH OVER MUCH OF THE GREAT LAKES
REGION AND MIDWEST ON FRIDAY/FRIDAY NIGHT. LATEST GFS AND EURO
MODEL RUNS ARE SHOWING MORE MOISTURE WITH AN ASSOCIATED COLD
FRONT...BUT INITIALIZATION NUMBERS ARE STILL TRENDING TOWARD A DRY
FRONTAL PASSAGE ON FRIDAY AFTERNOON/EVENING. AT THIS TIME...WILL
NOT MAKE ADJUSTMENTS TO INITIALIZATION NUMBERS UNTIL AFTER A FEW
MORE MODEL RUNS COME IN. OVERNIGHT LOWS WILL BE MORE REPRESENTATIVE
FOR THIS TIME OF YEAR WITH READINGS IN THE UPPER TEENS AND 20S DUE
TO THE CLEAR SKIES. THE AFOREMENTIONED COLD FRONT WILL LOWER
DAYTIME HIGHS A TAD ON SATURDAY...BUT THEY WILL QUICKLY INCREASE
BACK INTO THE UPPER 30S/LOW 40S BY SUNDAY AND MONDAY.
&&
.AVIATION /DISCUSSION FOR THE 06/18Z TAF ISSUANCE/...
EASTERN EDGE OF STRATUS/FOG DECK NEAR KOKOMO TO KHUF LINE WILL START
ERODING THIS AFTERNOON AND BOTH KHUF AND KLAF TAFS WILL IMPROVE TO
VFR BY LATE AFTERNOON. FARTHER WEST THAT THIS STRATUS DECK WILL
REMAIN INTACT AND START SPREADING EASTWARD AGAIN DURING THE
OVERNIGHT HOURS. THE RUC SOUNDING INDICATES THIS OCCURRING
OVERNIGHT AT MOST TAF SITES. BUT THERE IS MORE UNCERTAINTY WHETHER
THIS STRATUS/FOG DECK REACHES KBMG. FOR NOW WILL PLAY IT THAT
WAY...BUT HAPPENING LATER TONIGHT. THUS ALL TAFS WILL BECOME IFR OR
LIFR DURING THE OVERNIGHT HOURS. BUFKIT IS SOMEWHAT NEUTRAL ON
WHETHER THIS WILL BE MOSTLY STRATUS OR FOG. BUT IN AREAS WHERE
STRATUS ADVECT IN...IT MAY KEEP VISIBILITIES FROM DROPPING TOO LOW.
ON TUESDAY...THERE MAY BE SOME IMPROVEMENT ACROSS THE SOUTHERN HALF
OF OUR REGION. A COLD FRONT WILL MOVE INTO OUR REGION LATE TUESDAY.
WINDS WILL BE WEST OR SOUTHWEST AT 6 TO 8 KNOTS THIS AFTERNOON AND
LESS THAN 5 KNOTS TONIGHT.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
FREEZING FOG ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR INZ021-
028>031-035-036-043-044-051.
&&
$$
SYNOPSIS...RYAN
NEAR TERM...CP
SHORT TERM...RYAN
LONG TERM....TDUD
AVIATION...JH
AREA FORECAST DISCUSSION
NWS GRAND RAPIDS MI
1245 PM EST MON FEB 6 2012
LATEST UPDATE...AVIATION...
.SYNOPSIS...(404 AM EST MON FEB 6 2012)
A COLD FRONT WILL CROSS THE REGION TONIGHT. THIS SYSTEM WILL BRING
VERY LITTLE SNOW...HOWEVER IT WILL RETURN TEMPERATURES TO NEAR
NORMAL VALUES FOR MID WEEK. ANOTHER SURGE OF COLDER AIR ARRIVES BY
FRIDAY AND INTO THE WEEKEND. SOME LAKE EFFECT SNOW SHOWERS WILL BE
SEEN ALONG WITH THIS COLDER AIR.
&&
.SHORT TERM...(404 AM EST MON FEB 6 2012)
(TODAY THROUGH WEDNESDAY)
THE SKY FORECAST REMAINS THE BIGGEST CHALLENGE TODAY AND THE
RESULTANT AFFECTS ON THE REGION/S TEMPS. A LARGE AREA OF STRATUS
COVERED MUCH OF WISCONSIN THIS MORNING AND IT WAS PRESSING EASTWARD
AT A 5-10 MPH PACE. THAT SPEED ALONG WOULD SUGGEST THAT THE CLOUD
DECK WOULD NOT REACH THE MICHIGAN SHORE UNTIL MID AFTERNOON.
HOWEVER THERE WAS ALSO RANDOM PATCHES OF STRATUS ACROSS LOWER
MICHIGAN TOO. THE RUC LOW LEVEL MOISTURE PROGS SUGGEST A RAPID
EXPANSION OF THE STRATUS SO THAT THE ENTIRE GRR CWA IS COVERED BY
CLOUDS BY 12Z. THIS LOOKS UNREASONABLE TO ME. HOWEVER BELIEVE THE
STRATUS WILL LIKELY SPEED UP IT/S EASTWARD TRACK AS IT MOVES ACROSS
THE LAKE THIS MORNING. ALSO...THE RANDOM PATCHES MAY ALSO EXPAND
SOMEWHAT THIS MORNING. BUT THEN THE ISSUE BECOMES...WHAT WILL THE
INCREASED MIXING DO TO THE STRATUS. I SENSE THAT IT WILL HELP IT TO
ERODE SUCH THAT MUCH OF THE STRATUS BECOMES LESS OF A FACTOR BY MID
DAY. SO I WILL PLAY THE FORECAST SUCH THAT SOME STRATUS WILL LINGER
THROUGH THE MORNING...BUT WILL BANK ON A MOSTLY SUNNY AFTERNOON AS
THE EASTWARD EDGE OF THE STRATUS MIXES OUT. IF THIS INDEED OCCURS
TEMPS WILL REACH WELL INTO THE 40S AGAIN TODAY...IF IT DOES NOT
OCCUR TEMPS MAY HOLD FROM 35 TO 40.
THE ARCTIC FRONT IS STILL ON SCHEDULE FOR TONIGHT. THE LACK OF DEEP
MOISTURE WILL RESULT IN NO SNOW OR PERHAPS A RANDOM FLURRY. THE LOW
LEVEL FLOW BEHIND THE FRONT SHOULD BE 030-040...KEEPING ANY LAKE
EFFECT ON THE OTHER SIDE OF THE LAKE. WE WILL HAVE TO KEEP AN EYE
ON POSSIBLE SNOW SHOWERS OFF OF SAGINAW BAY WHICH MAY MOVE INTO
AREAS AROUND ST. JOHNS BY TUESDAY.
HAVE LOW POPS IN FOR TUE AFTERNOON INTO TUESDAY NIGHT FOR AREAS
SOUTH OF I-96. A SHORT WAVE COMES ACROSS THE LOWER GREAT LAKES AND
COMBINED WITH THE EXITING ARCTIC FRONT MAY PRODUCE SOME LIGHT SNOW.
LOW LEVEL WINDS SHOULD ALSO BACK TO THE NW BY LATE TUESDAY NIGHT
WHICH COULD BRING A FEW SNOW SHOWERS OFF THE LAKE. BY WEDNESDAY THE
MOISTURE PROFILE BECOMES VERY SHALLOW AS RIDGING BUILDS INTO THE
AREA. EXPECT SUNSHINE WITH NEAR NORMAL TEMPS.
&&
.LONG TERM...(404 AM EST MON FEB 6 2012)
(WEDNESDAY NIGHT THROUGH SUNDAY)
A CLIPPER MOVES ACROSS NORTHERN LOWER MICHIGAN THURSDAY NIGHT
SWINGING AN ARCTIC FRONT SOUTH ACROSS THE FORECAST AREA.
LOOKS LIKE SOME SNOW WILL ACCOMPANY THE FROPA WITH STRONG SFC
CONVERGENCE. LAKE EFFECT BEHIND THE FRONT WILL CONTINUE INTO
SATURDAY BUT FLOW GOES NORTH AND THEN EVENTUALLY NORTHEAST WHICH
WOULD PUSH THE SNOW SHOWERS OFFSHORE. THIS COMBINED WITH INVERSION
HEIGHTS BELOW 10 KFT SHOULD LIMIT ACCUMS...WITH MOST OF THE SNOW
CONCENTRATED FAIRLY CLOSE TO THE LAKE MICHIGAN SHORE.
&&
.AVIATION...(1245 PM EST MON FEB 6 2012)
MAIN FOCUS WITH THIS FCST PACKAGE IS THE LOW CLOUD TRENDS. LOW
CLOUDS WITH MVFR AND IFR CONDITIONS HAVE OVERSPREAD JUST ABOUT ALL
OF THE AREA WEST OF INTERSTATE 69 THIS MORNING. KJXN AND KLAN HAVE
REMAINED EAST OF THE CLOUD COVER...AND DIURNAL MIXING SHOULD PREVENT
THE LOW CLOUDS FROM MOVING INTO THOSE AREAS. THE AIRPORTS THAT
CURRENTLY HAVE THE LOW CLOUDS IN PLACE SHOULD SEE A SLOW LIFTING OF
THE CIGS...AND THE CLOUDS SHOULD BREAK UP FROM EAST TO WEST AS
DIURNAL MIXING DISSIPATES THE CLOUD COVER. WHERE CLOUDS BREAK UP
WILL SEE THE BETTER POTENTIAL OF SOME WIND GUSTS UP AROUND 20 KNOTS
THROUGH SUNSET.
A COLD FRONT WILL APPROACH THE AREA THIS EVENING FROM THE NORTH.
MAINLY MVFR LOW CLOUDS AHEAD OF THE FRONT WILL MOVE IN AFTER
00Z...AND THE FRONT SHOULD THEN MOVE THROUGH A FEW HOURS LATER.
CLOUDS SHOULD BE THE MAIN IMPACT FROM THE FRONT ALONG WITH A WIND
SHIFT FROM W/SW TO NE. SOME FREEZING DRIZZLE WILL ALSO BE
POSSIBLE...BUT WE ARE NOT CONFIDENT ENOUGH AT THIS TIME TO MENTION
IN THE FCST. THE CLOUDS AND NE WINDS WILL HOLD IN THROUGH 18Z TUE.
&&
.MARINE...(404 AM EST MON FEB 6 2012)
SCA IN AFFECT FOR TODAY WITH WSW WINDS TO AROUND 20 KTS. LOOKS LIKE
WE WILL SEE A BRIEF BREAK IN THE HIGHER WINDS AND WAVES EARLY
TONIGHT AS A COLD FRONT COMES THROUGH. BUT THEN BEHIND THE FRONT
WAVES SHOULD INCREASE AGAIN LATE TONIGHT OR EARLY TUESDAY IN THE
COLD ADVECTION PATTERN.
&&
.HYDROLOGY...(404 AM EST MON FEB 6 2012)
MINIMAL HYDRO CONCERNS GIVEN THE LACK OF PCPN. ALSO THE SNOW PACK
TO THE NORTH WILL END IT/S MELTING BY TONIGHT AS THE COLD FRONT
COOLS REGIONAL TEMPS.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LM...SMALL CRAFT ADVISORY ST. JOE TO MANISTEE THROUGH TODAY.
&&
$$
SYNOPSIS: JK
SHORT TERM: JK
LONG TERM: OSTUNO
AVIATION: NJJ
MARINE: JK
HYDROLOGY: JK
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1224 PM EST MON FEB 6 2012
UPDATED AVIATION DISCUSSION FOR 18Z TAFS
.SYNOPSIS...
IN CONTRAST TO LAST COUPLE NIGHTS...CLEAR SKIES ARE DOMINANT ACROSS
UPR MI THIS MORNING. STRATUS IS NOT TOO FAR AWAY THOUGH OVR MN AND
WI. SO FAR...THERE IS ENOUGH WIND OVR UPR MI TO PROHIBIT THE STRATUS
FM SURGING INTO UPR MI. COLD FRONT THAT WILL BRING A CHANGE TO THE
RECENT UNSEAONABLE WARMTH IS DROPPING ACROSS MANITOBA AND ONTARIO
THIS MORNING. STRATOCU IS INITIAL SIGN OF THE COLDER AIR WITH SFC
OBS TURNING UP SOME LGT SNOW BEHIND THE FRONT OVR NORTHERN ONTARIO.
COLDER AIR ARRIVING LATE TODAY AND TONIGHT WILL LEAD TO LK EFFECT
SNOW SHOWERS OVR NORTHERN UPR MI. AS HAS BEEN CASE MUCH OF THIS
WINTER...THIS COOL DOWN WILL BE BRIEF WITH TEMPERATURES MOVING BACK
TOWARD NORMAL AS SOON AS WEDNESDAY. APPEARS THAT MORE SUBSTANTIAL
COOL DOWN WILL RETURN BY LATE WEEK INTO THE WEEKEND AS PORTION OF
POLAR VORTEX OVER EASTERN CANADA SLIDES INTO GREAT LAKES/NORTHEAST
CONUS.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...
IN THE NEAR TERM...QUIET CONDITIONS AS SKIES SHOULD STAY MOSTLY
CLEAR. RUC13 PERFORMED WELL WITH STRATUS YDY...AND IT DOES INDICATE
STRATUS MAY TRY TO MAKE MOVE INTO SW FRINGES OF UPR MI FM WISCONSIN.
SINCE RUC13 IS OVERDOING NORTHERN EXTENT TO CLOUDS AT THIS HOUR...WILL
KEEP WITH MAINLY CLEAR SKIES. DESPITE THE CLEAR SKIES...TEMPS ARE
STILL IN THE UPR 20S TO LOWER AND EVEN MID 30S WITH STEADY WEST WINDS
BLOWING AHEAD OF COLD FRONT DROPPING ACROSS ONTARIO. ISOLATED INLAND
LOCATIONS WHERE WINDS GO CALM COULD STILL FALL TO LOW-MID 20S THROUGH
SUNRISE /ALREADY HAVE SOME 25F READINGS AT WAKEFIELD AND DOE
LAKE/...BUT FOR LARGE PART TEMPS WILL REMAIN STEADY ELSEWHERE.
TODAY...
COLD FRONT FCST TO MOVE INTO FAR NORTH CWA TOWARD MIDDAY. FRONT
SHOULD REACH SOUTHERN CWA AROUND KMNM BY 21Z THIS AFTN. STRATOCU MAIN
ISSUE INITIALLY AS THERE IS NOT A LOT OF COLD AIR AROUND JUST IN WAKE
OF FRONT...WITH H85 TEMPS WARMER THAN -8C. KEPT ISOLATED SNOW SHOWERS
RESTRICTED TO NW CWA THIS AFTN AS COOLER AIR GRADUALLY FILTERS INTO
UPR MI. OTHERWISE...BASED ON UPSTREAM TRENDS IN ONTARIO THIS
MORNING...MOST AREAS COULD SEE SOME FLURRIES JUST IN WAKE OF FROPA.
TEMPS SHOULD FALL OFF WITH PASSAGE OF FROPA...BUT DOES APPEAR THAT
SHARPER COOLING IS LAGGING INITIAL SURGE OF STRATOCU BY A FEW HOURS.
HEADED TOWARD REGIONAL CANADIAN FOR TEMPERATURE TRENDS TODAY. BASED
ON WARM START THIS MORNING AND WEST WINDS ALREADY STIRRING...SEEMS
LIKELY THAT DOWNSLOPE AREAS OF CNTRL /MARQUETTE TO ESCANABA TO
MENOMINEE/ HAVE SHOT TO REACH INTO 40S BY EARLY AFTN JUST AHEAD OF
FRONT. BY LATE AFTN...EXPECT MOST AREAS TO BE AT OR BLO
FREEZING...WITH 20S LIKELY IN THE HIGHER TERRAIN OF NW AND NCNTRL UPR
MI.
TONIGHT INTO TUESDAY...
REALLY GOOD AGREEMENT ON SPECIFICS FM 00Z GUIDANCE WITH EXTENT AND
DEPTH OF COLD AIR /H85 TEMPS AROUND -15C/ AND MOISTURE /AT LEAST UP
TO 5KFT WHICH INTERSECTS IDEAL DENDRITIC SNOW GROWTH ZONE/. WIND
FIELDS ARE ALSO IN GOOD AGREEMENT WHICH IS A PLUS WHEN DEALING WITH
LK EFFECT. HAVE LEANED ON BLEND OF HIGHER RESOULTION 5KM NAM AND NCEP
HIGH RES WRF-ARW/NMM FOR POP/QPF DETAILS FOR LK EFFECT. IN REALITY
THIS DID NOT RESULT IN MUCH CHANGE TO PREVIOUS FCST. ONLY EXCEPTION
WAS TO TRIM LK EFFECT POPS BACK OVR MUCH OF GOGEBIC/ONTONAGON/IRON AS
BLYR WINDS ARE NOW NORTHEAST COMPARED TO NORTH. DIFFLUENCE SHOWS UP
IN WINDS OVR WESTERN INTERIOR UPR MI AS WELL...SUGGESTING THAT LK
EFFECT IN THE WEST SHOULD STAY PINNED CLOSER TO LK SUPERIOR SHORE
/KIWD THROUGH PORCUPINE MOUNTAINS AND ALONG SHORE AT ONTONAGON UP
INTO KEWEENAW/.
AT THE SAME TIME...LOW-LEVEL FLOW IS MORE CYCLONIC AND FM THE NNE
OVR NCNTRL CWA FOR MUCH OF THE NIGHT LEADING TO BETTER CHANCE OF
SEEING MODERATE SNOW AMOUNTS. FCST SOUNDINGS SHOW MOISTURE THROUGH H8
/7KFT/ THROUGH ABOUT 09Z THEN MOISTURE SETTLES BLO H85/5KFT TOWARD
DAYBREAK TUESDAY. OVER-WATER INSTABILITY IS SUFFICIENT FOR MODERATE
LAKE EFFECT AS LAKE INDUCED EQL RISE UP OVR 5KFT WITH SFC-H85 DELTA
T/S NEARING 20C. LK EFFECT SNOW PARAMETER PICKS UP ON THIS AND
DEEPER MOISTURE/UNIDIRECTIONAL LOW-LEVEL WINDS WITH POCKET OF HIGHER
VALUES BTWN 03Z AND 09Z TONIGHT. LOCAL LK EFFECT GUIDANCE SUGGESTS
12 HR SNOW AMOUNTS UP TO 6 INCHES IN THIS SETUP. UNDERCUT THIS
SLIGHTLY SINCE IDEAL LK EFFECT CONDITIONS WILL PROBABLY
ONLY BE REALIZED FOR 6-9 HRS DUE TO MARGINAL COLD AIR INITIALLY
TONIGHT AND DEEPER MOISTURE PULLING AWAY IN THE 09Z-12Z PERIOD.
THESE NEGATIVES MAY BE OFFSET BY HIGHER SLR/S AND FLUFFY NATURE OF
THE SNOW SINCE MAJORITY OF MOIST CONVECTIVE LAYER IS IN THE HEART OF
THE DGZ. SNOW RATIOS FM NAM COBB OUTPUT ARE IN THE 20-25:1.
EVEN AS DEEPER MOISTURE LEAVES FIRST THING TUESDAY MORNING...EXPECT
COVERAGE OF SNOW SHOWERS TO REMAIN HIGH THROUGH MOST OF TUESDAY
MORNING THOUGH INTENSITY SHOULD BE KNOCKED DOWN LARGELY DUE TO
INVERSIONS FALLING BLO 4KFT. OVERALL...TOTAL SNOW ACCUMS FM THIS
EVENING THROUGH EARLY TUESDAY AFTN COULD NEAR 6 INCHES IN SPOTS OVR
HIGHER TERRAIN FM HURON MOUNTAINS TO ISHPEMING/NEGAUNEE AND SKANDIA
AREAS AND INTO WESTERN ALGER COUNTY FM DEERTON TO CHATHAM. 12 HR
SNOW AMOUNTS ARE ONLY MARGINALLY SUFFICIENT FOR ADVY THOUGH AND
SINCE THERE IS NOT MUCH FOR ADDITIONAL HAZARDS /CONSIDERABLE BLSN
FOR EXAMPLE/ HAVE HELD OFF ON ISSUING ADVY ATTM. WILL LET DAYSHIFT
TAKE ONE MORE LOOK AT DETAILS AND PUT HEADLINE UP IF NEEDED. NORTH
WINDS BACK MORE NORTHWEST BY LATE TUESDAY AFTN...SHIFTING
DIMINISHING SNOW SHOWERS ACROSS MUCH OF ALGER COUNTY. AWAY FM
LK EFFECT TUESDAY...MAIN ISSUE WILL BE RETURN TO WINTER WITH
TEMPERATURES IN THE TEENS/20S AND WIND CHILL READINGS IN THE
SINGLE DIGITS ABOVE ZERO FOR MUCH OF THE DAY. BASICALLY THAT IS
FAIRLY TYPICAL FOR THIS TIME OF YEAR...BUT GIVEN THE RECENT WARMTH
IT WILL DEFINITELY FEEL ON THE CHILLY SIDE.
&&
.LONG TERM /TUE NIGHT THRU SUN/...
TUE NIGHT...SHRTWV RDG/SFC HI PRES WL DOMINATE. WITH MOCLR SKIES...
LGT WINDS...AND PWAT AS LO AS 0.10-0.15 INCH OR 40-50 PCT OF
NORMAL...EXPECT TEMPS OVER THE INTERIOR SRN TIER TO DIP AOB THE LO
END OF GUIDANCE. AS THE SFC RDG SINKS SLOWLY TO THE S THRU THE
NGT...A STRONGER W WIND WITH H925 WINDS UP TO 30 KTS WL INFLUENCE
AREAS NEAR LK SUP AND LIMIT THE DIURNAL TEMP FALL THERE.
WED...CWA WL BE UNDER STRENGTHENING WLY FLOW/H925 WINDS UP TO 35 KTS
BTWN HI PRES RDG SINKING TOWARD THE OH RIVER VALLEY AND ANOTHER LO
PRES/ATTENDANT COLD FNT TRACKING ACRS NRN ONTARIO ASSOCIATED WITH
SHRTWV WITHIN DEEPENING UPR TROF OVER HUDSON BAY. WITH DRY
AIRMASS/PWAT ARND 0.15 INCH LINGERING...EXPECT A MOSUNNY DAY. H85
TEMPS ARE PROGGED TO REBOUND TO ARND -5C...SO THE DAY WL BE WARMER.
BUT GUSTY W WIND WL MAKE THE AIR FEEL COLDER DESPITE SLOWLY INCRSG
SOLAR ANGLE.
WED NIGHT...COLD FNT ASSOCIATED WITH DEEPENING UPR TROF CENTERED
NEAR HUDSON BAY IS FCST TO DROP INTO NRN LK SUP BY 12Z THU. LACK OF
ANY MSTR INFLOW/DRY NATURE OF ANTECEDENT AIRMASS ARGUES FOR A DRY
FCST WITH LTL IN THE WAY OF PRE-FRONTAL CLD COVER AS WELL...BUT DID
INTRODUCE SOME SCHC POPS OVER THE N HALF OF LK SUP OVERNGT TO MARK
ARRIVAL OF THIS FNT. ALTHOUGH PWAT IS FCST TO REMAIN LO ARND 0.15
INCH...STEADY W WIND WL LIMIT THE DIURNAL FALL OF TEMP.
EXTENDED...MODELS NOW IN GOOD AGREEMENT FOR THU SHOWING A SHARP COLD
FROPA WITH ONLY A WEAK SFC LO RUNNING ALONG THIS BNDRY...IN CONTRAST
TO SOME PAST MODEL RUNS THAT DEPICTED A DEEPER LO. WITH DRY AIRMASS
PRECEDING THE FROPA...WENT NO HIER THAN CHC POPS EVEN NEAR LK SUP.
INFUSION OF MUCH COLDER AIR BEHIND THIS FROPA WITH 00Z GFS SHOWING
H85 TEMPS FALLING AS LO AS -25C AND INVRN BASE ARND 5K FT WL RESULT
IN SOME LES...MOST PREVALENT IN AREAS FAVORED BY FCST NNW FLOW THRU
FRI. TENDED TO GO HIER THAN MODEL CONSENSUS POPS IN THESE FAVORED
AREAS GIVEN TENDENCY FOR MODELS TO UNDERDO LES. THEN AS ARCTIC HI
PRES DRIFTS SEWD TOWARD THE UPR MIDWEST ON SAT...BACKING FLOW TO
MORE W WL SHIFT THE LES INTO AREAS FAVORED BY THAT FLOW. LINGERING
LES SHOULD DIMINISH/END ON SUN AS UPR TROF LIFTS OUT/FLOW TURNS MORE
ACYC WITH HI PRES DRIFTING INTO THE OH RIVER VALLEY. NEAR NORMAL
TEMPS ON THU WL SINK AOB NORMAL THU NGT THRU SAT AS ARCTIC AIRMASS
INVADES THE UPR LKS. TEMPS WL REBOUND ON SUN WITH BLDG UPR RDG INTO
THE GRT LKS/RETURN LLVL SW FLOW OF WARMER AIR TO THE N OF SFC HI IN
THE OH VALLEY.
&&
.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1222 PM EST MON FEB 6 2012
COLD FRONT DROPPING S OVER LAKE SUPERIOR WILL PASS ACROSS
KCMX/KIWD/KSAW THIS AFTN. UPSLOPE WESTERLY FLOW AHEAD OF FRONT HAS
RESULTED IN IFR CIGS AT KCMX. AS WINDS SHIFT NORTHERLY BEHIND
FRONT...CIGS SHOULD RISE TO MVFR AS IDEAL UPSLOPE COMPONENT IS LOST.
ON THE OTHER HAND...KIWD/KSAW SHOULD SEE LOW MVFR CIGS/POSSIBLE IFR
DEVELOP AS WINDS SHIFT TO AN UPSLOPE NORTHERLY DIRECTION BEHIND
FRONT. A FEW FLURRIES ARE POSSIBLE LATER IN THE AFTN AS AIRMASS
COOLS...BUT LAKE EFFECT -SHSN PROBABLY WON`T DEVELOP UNTIL THE
EVENING WHEN OVERWATER INSTABILITY BECOMES GREATER. NNE FLOW WILL
FAVOR KIWD/KSAW FOR MORE PERSISTENT/HEAVIER SHSN AND LOWER MVFR
CONDITIONS. FLOW IS MOST IDEAL FOR KSAW...AND VIS THERE WILL
PROBABLY DROP TO IFR ON A FREQUENT BASIS THOUGH CIGS MAY STAY AOA
1KFT. DIMINISHING OF LAKE EFFECT SHSN/IMPROVEMENT EXPECTED AT ALL
SITES TUE MORNING AS FLOW BECOMES INCREASINGLY ANTICYCLONIC...
INVERSION FALLS AND DRIER AIR ARRIVES.
&&
.MARINE /FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE/...
EXPECT W WINDS UP TO 30 KTS EARLY TODAY TO WEAKEN A BIT WITH THE
APPROACH OF A COLD FRONT BUT THEN VEER TO THE N BY THIS EVNG AND
CRANK BACK UP TO 30 KTS FOLLOWING A COLD FRONTAL PASSAGE. THERE MAY
BE SOME GALE FORCE GUSTS TO 35 KTS AS WELL SINCE THE ARRIVAL OF MUCH
COLDER AIR OVER THE RELATIVELY WARM LAKE WATERS ENHANCES MIXING.
HOISTED A HEAVY FREEZING SPRAY WARNING FOR MUCH OF CENTRAL LAKE SUP
WITH INVASION OF ARCTIC AIR/HIER WAVES FORECAST IN THIS AREA INTO
TUE MORNING. THESE AUSTERE CONDITIONS WILL IMPROVE ON TUE WITH THE
ARRIVAL OF A HI PRES RIDGE/LIGHTER WINDS IN THE AFTERNOON. LIGHT
WINDS ON TUE EVENING ASSOCIATED WITH THE PASSING SFC HI PRES RIDGE
WILL INCREASE UP TO 30 KTS BY WED MORNING AS PRES GRADIENT SHARPENS
ONCE THE HI SINKS TOWARD THE OH RIVER VALLEY. THERE MAY BE A FEW
GALE FORCE GUSTS TO 35 KTS OVER THE E WITH LONGER FETCH OF CHILLY
AIR OVER THE RELATIVELY WARM LAKE WATERS ALLOWING FOR MORE MIXING.
ALTHOUGH WINDS MAY DIMINISH LATE WED NIGHT INTO THU FOR A TIME AS
ONLY A WEAK LO PRES CENTER MOVES JUST TO THE NE OF THE LAKE...
EXPECT A STRONGER NNW FLOW TO 30 KTS TO DEVELOP FOLLOWING A COLD
FRONTAL PASSAGE ON THU. THE COMBINATION OF THESE STRONG WINDS AND
THE ARRIVAL OF VERY COLD AIR MAY RESULT IN HEAVY FREEZING SPRAY OVER
PORTIONS OF THE LAKE THRU THU NIGHT. THE CLOSER APPROACH OF A HI
PRES RIDGE WILL BRING DIMINISHING WINDS BY FRI.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
UPPER MICHIGAN...
NONE.
LAKE SUPERIOR...
HEAVY FREEZING SPRAY WARNING FROM 10 PM EST /9 PM CST/ THIS
EVENING TO 10 AM EST /9 AM CST/ TUESDAY FOR LSZ241>244-263-
264.
LAKE MICHIGAN...
NONE.
&&
$$
SYNOPSIS...JLA
SHORT TERM...JLA
LONG TERM...KC
AVIATION...ROLFSON
MARINE...KC
AREA FORECAST DISCUSSION...UPDATED FOR 18Z TAFS
NWS TWIN CITIES/CHANHASSEN MN
1140 AM CST MON FEB 6 2012
.DISCUSSION...ISSUED 322 AM CST
STILL A COMPLICATED CLOUD TREND THIS MORNING. THERE DOES SEEM TO
BE A BIT STRONGER EASTWARD PUSH OF THE CLOUD EDGE WEST OF MSP PER
THE MORE WEST COMPONENT SEEN IN THE LOW LEVELS. A DIFFERENT STORY
OVER FAR SOUTHERN MN. THAT EDGE HAS A SLOW NORTHWARD DRIFT WHICH
MAY CONTINUE AND PROBABLY KEEP SOUTH CENTRAL MN AND PARTS OF
WEST CENTRAL WI IN THE CLOUDS THOUGH THE MORNING. THE HRRR HAS HAD
THE BEST TREND ON THE LOW CLOUDS SINCE YESTERDAY...SO WILL TRY TO
FOLLOW THIS IN THE VERY SHORT TERM. THIS WILL OBVIOUSLY HAVE
IMPLICATIONS ON THE HOURLY TEMP TRENDS.
THE ARCTIC FRONT IS WELL MARKED WITH THE CLOUDS EDGE PUSHING
SOUTH OVER SOUTHERN CANADA..WILL WORK INTO OUR NORTHERN AREAS
THIS AFTERNOON. WILL USE MORE OF A MODEL DIURNAL TEMP TREND TODAY
WITH HIGHS REACHED EARLY IN THE FAR NORTHWEST ALONG WITH THE CLOUD
ISSUES IN THE SOUTH. STILL A DECENT CHANCE OF 40S FOR HIGHS IN THE
SOUTH. SOME MINOR LIFT WITH THE FRONT TONIGHT...AND THERE IS A
HINT OF PV ADVECTION LATE TONIGHT OVER FAR SOUTHERN MN FROM THE
SYSTEM TO OUR SOUTHWEST. WILL KEEP THE FLURRIES IN THE FORECAST
TONIGHT AND TUESDAY MORNING WITH THE FRONT AND WAIT ON THE
POSSIBILITY OF A SLIGHT CHANCE POP IN THE FAR SOUTH. THERE IS A
MINOR RISK OF FREEZING DRIZZLE WITH LACK OF MID LEVEL MOISTURE
UNTIL TUESDAY MORNING...BUT WITH A TIMING AN LOCATION
ISSUE...WILL WAIT ON THAT AS WELL.
A STRONGER FRONT STILL FORECAST TO AFFECT THE AREA THURSDAY AND
FRIDAY AND THE ECMWF HAS COME AROUND A LITTLE MORE IN LINE TO THE
GFS/GEM WITH THE STRENGTH. STILL A FAIR AMOUNT OF UNCERTAINTY IN
THE GFS ENSEMBLE TEMPS STARTING FRIDAY AND CONTINUING INTO THE
WEEKEND. EVEN THOUGH THE ECMWF LOOKS COLD FOR FRIDAY...IT`S TREND
FOR A GLANCING BLOW IS STILL THERE WITH A FLATTENING OF THE RIDGE
OUT WEST DURING THE WEEKEND. OUR CURRENT BLENDED FORECAST FOR
FRIDAY TEMPS MAY BE A BIT HIGH BUT THAT CAN STILL BE ADDRESSED IN
THE NEXT DAY OR TWO.
&&
.AVIATION.../18Z TAF ISSUANCE/
IFR/LIFR CIGS/VSBYS WHICH HAVE PLAGUED THE AREA FOR ABOUT THE PAST
5 DAYS HAVE NOW SHIFTED EAST OF ALL TAF SITES. SKC CURRENTLY ACROSS
AREA...WILL HOWEVER THIS WILL BE BRIEF AS WIDESPREAD AREA OF MAINLY
MVFR CIGS CURRENTLY ADVANCING SOUTH ACROSS N MN IN WAKE OF CDFNT
PUSHES ACROSS AREA. CDFNT AT 17Z RUNS FROM AROUND STC TO NEAR MVE.
CLOUDS LAG SFC FRONT WITH LEADING EDGE FROM N OF DLH TO NEAR DTL.
MAY SEE A FEW CU/SC DEVELOP AHEAD OF MAIN BAND OF CLOUDS DURING THE
AFTERNOON. NICE AREA OF 5MB 3 HRLY SFC PRESSURE RISES IN WAKE OF
CDFNT WILL KEEP IT ADVANCING SOUTH...AND NW WNDS SHOULD DEVELOP AT
ALL TAFS BY 21-23Z. EXPECT GUSTS AROUND 20KTS TO DEVELOP A COUPLE
HOURS AFTER FROPA WITH WINDS REMAINING GUSTY THRU MUCH OF OVERNITE.
MAY BE A FEW -SHSW MAINLY DURING THE EVENING AS CLOUDS THICKEN...
BUT VSBYS SHUD REMAIN AOA 6SM. GOOD DRYING BEGINNING TUESDAY
MORNING AS 1040 HIGH PRESSURE BUILDS ACROS N MN. MVFR CEILINGS
ELSEWHERE. SOUTHWEST TO WEST WINDS AHEAD OF FRONT...BECOMING
NORTHWEST TO NORTH AND A BIT GUSTY WITH FROPA.
KMSP...NICE PRD OF SKC. CDFNT APPROACHING MSP WITH WINDS JUST
TURNING WNW AT MGG AND HCD. TREND FROM 18Z TO 20Z WILL BE FOR SFC
WNDS TO TURN FROM AROUND 250 TO 290 AND THEN BECOMING 330. SPEEDS
GENERALLY AOB 10 KTS UNTIL AFTER 21Z WITH GUSTS DEVELOPING 20 KTS
BY 00Z. MAY SEE FEW015 CU DEVELOPING IN WAKE OF CDFNT WITH MVFR
CIGS MVG INTO AREA BY 01Z. GENERALLY MVFR CIGS UNTIL AROUND
15Z-17Z...THEN CLEARING AS HIGH PRESSURE BUILDS IN.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...NONE.
WI...NONE.
&&
$$
JPR/BAP
AREA FORECAST DISCUSSION...UPDATED
NWS GLASGOW MT
914 AM MST MON FEB 6 2012
.SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH WEDNESDAY...
SENT AN UPDATE THIS MORNING TO REMOVE MORNING WORDING OF FREEZING
FOG AND TO ADD SOME FLURRIES PER CURRENT RADAR TRENDS. MOST OF THE
PRECIPITATION NORTH OF THE LITTLE ROCKIES WILL LIKELY REMAIN VIRGA
BUT FOR POINTS AROUND AND SOUTH OF THE LITTLE ROCKIES MAY SEE
SMALL ACCUMULATIONS OF SNOW TODAY AS THE COLD FRONT CONTINUES TO
PUSH SOUTHWARD. BMICKELSON
PREVIOUS SHORT TERM DISCUSSION...REX BLOCK OVER THE W STATES/W
CANADA CONTINUES...HOWEVER NE MT ON THE W EDGE OF NNW FLOW AROUND
THE LARGE HUDSON BAY UPPER LOW COMPLEX. THIS HAS BEEN BRINGING
COLDER AIR INTO OUR AREA...WHICH STARTED LAST NIGHT...WHICH WILL
CONTINUE TODAY...RESULTING IN HIGHS 15F OR MORE COLDER THAN
YESTERDAY. STRONGEST 850 MB WINDS OF UP TO 30 KT IN OUR N THIS
MORNING. WE WILL BE ALMOST DRY ADIABATICALLY MIXED...AND ALMOST TO
THIS LEVEL...SO A LITTLE BIT WINDY THIS MORNING IN COLD ADVECTION
PATTERN.
THE COLDER AIR MASS IS ASSOCIATED WITH A 1045 MB SURFACE HIGH
PRESSURE CENTERED ON NE AB/NW SK BORDER THAN WILL MOVE TO OUR NE
BORDER LATE TONIGHT AND TUE. THE AIR MASS WITH THIS IS MOIST IN
LOWER LEVELS...BUT NOT PARTICULARLY COLD FOR THIS TIME OF YEAR.
OBS INDICATE NARROW TEMP/DEW POINT SPREADS IN OUR FORECAST AREA
OVERNIGHT AND EARLY THIS MORN...AND SIGNS OF VISIBILITY
REDUCTION. THERE ARE ALSO AREAS OF MULTIPLE AND EXPANDING LOWER
CLOUD LAYERS APPROACHING FROM THE NW AND N. MODELS INDICATE THIS
EXPANSION AS WELL AS LOWERING CEILINGS WILL CONTINUE...WITH RUC
AND HRRR SEEMING TO DO THE BEST WITH IT. THUS EXPECT SOME HIGHER
ELEVATIONS WILL END UP WITH FOG FROM THIS. ENOUGH WIND TO KEEP
LOWER ELEVATION FOG MORE PATCHY AND LESS VISIBILITY REDUCTION.
WILL ISSUE A HAZARDOUS WEATHER OUTLOOK (HWO).
THIS OVERCAST/FOG WILL LIFT SOME THIS AFTERNOON...THEN CLEAR OUT
TONIGHT BEHIND THE PASSAGE OF AN UPPER TROUGH...AND AS THE SURFACE
HIGH PUSHES IN. COLDER PART OF THE AIR MASS IS TONIGHT AND TUE WITH
THICKNESSES DOWN TO 510 DM AND 850 MB TEMPS AS LOW AS -13C IN OUR
AREA. MODELS ARE IN GOOD AGREEMENT DURING THE ENTIRE PERIOD.
THE SURFACE HIGH MOVES SE OUT OF THE AREA WED...ALLOWING FOR THE
WARMING OF THE AIR MASS. IT LEAVES BEHIND RATHER WEAK SURFACE
PRESSURES THOUGH AND CONTINUED DRY AIR MASS. RESULT IS SUNNY AND
A LITTLE WARMER WED WITH WINDS ON THE LIGHT SIDE. MODELS ARE
QUITE A BIT SLOWER THAN YESTERDAY WITH THE APPROACH OF THE NEXT
COLD FRONT FROM THE N. SIMONSEN
.LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY...
THE EXTENDED BEGINS WITH A LARGE UPPER LOW OVER NORTHERN QUEBEC
PROVINCE... RIDGING OVER THE WEST COAST WITH ANOTHER UPPER LOW
OVER THE KAMCHATKA PENINSULA IN FAR EASTERN RUSSIA. THE WEST COAST
RIDGE EXTENDS WELL INTO THE ARCTIC PROVIDING DRY NORTHERLY FLOW
FOR NORTHEAST MONTANA. AS THE FORECAST MOVES INTO THE WEEKEND THE
UPPER LOW OVER QUEBEC WEAKENS AND LIFTS INTO GREENLAND AS THE
KAMCHATKAN LOW MOVES INTO THE WESTERN BERING SEA. THE UPPER LOWS
ACTION OF PULLING APART ALLOWS THE WEST COAST RIDGE TO BREAK DOWN.
THE RESULT IS A MORE ZONAL FLOW KEEPING THE WEATHER PATTERN IN THE
DRY AND ABOVE NORMAL RANGE. MONDAY AND TUESDAY A TROUGH OF LOW
PRESSURE IS FORECAST TO DIG INTO THE AREA BRINGING A SLIGHT
POSSIBLY OF PRECIPITATION.
MODEL CONFIDENCE IS FAIR TO ABOVE NORMAL AT THE START OF THE
EXTENDED THROUGH SATURDAY AT 12Z WHEN THE MODELS HANDLE AN UPPER
LOW MOVING ONSHORE IN CENTRAL CALIFORNIA VERY DIFFERENTLY. LIKE
THE EC HANDLING OF IT AS A WEAK TROUGH OVER THE GEM/S OVER
DEEPENING AND THE GFS/S SLOWER MOVEMENT. FOR DAY 6 THROUGH DAY 8
THE GFS AND EC ARE SIMILAR FOR FAIR MODEL CONFIDENCE...THE GEM HAS
GONE IN A DIFFERENT DIRECTION.
TEMPS/PRECIPITATION FOR THE EXTENDED DOES NOT APPEAR TO HAVE MUCH
CHANGE FROM THE PAST COUPLE OF WEEKS. NO MAJOR CHANGE EXPECTED IN
THE EXTENDED. PROTON
&&
.AVIATION...
A WIDE BAND OF MVFR CLOUDS WILL SLIDE ACROSS THE REGION THIS
MORNING AND THROUGH EARLY AFTERNOON. EXPECT THESE CLOUDS TO CLEAR
THE REGION THIS EVENING FOR A RETURN OF VFR CONDITIONS WITH HIGH
PRESSURE OVER EASTERN MONTANA INTO TUESDAY. RAE
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
WEATHER.GOV/GLASGOW
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1123 AM CST MON FEB 6 2012
.DISCUSSION...
WILL LET THE DENSE FOG ADVISORY FOR WESTERN IOWA EXPIRE ON SCHEDULE
AT 18Z.
&&
.AVIATION...18Z TAFS FOR KOMA...KLNK...KOFK.
SOMEWHAT COMPLICATED SET OF TAFS THIS CYCLE FOR A VARIETY OF
REASONS. SOME MVFR FOG WILL STILL BE POSSIBLE AT KOMA TIL ABOUT
19Z...AND COULD REDEVELOP THIS EVENING BEFORE A COLD FRONT
ARRIVES. OTHERWISE...THE MAIN FOCUS WOULD BE THE COLD FRONT...
SWITCHING WINDS FROM THE WEST SOUTHWEST AHEAD OF THE FRONT...TO
THE NORTHWEST BEHIND. ALSO EXPECTING MVFR CEILINGS TO DEVELOP
BEHIND THE COLD FRONT...AT KOFK BY ABOUT 05Z...AND KOMA/KLNK BY
08-09Z. ALSO HAVE SOME CONCERN FOR SOME PATCHY FREEZING DRIZZLE AT
KOFK 07-10Z...BEFORE DEEPER SATURATION ARRIVES RESULTING IN ICE
CRYSTAL DEVELOPMENT...WHICH COULD BRING SOME SNOW TO THE SITES
LATE IN THE TAF PERIOD WITH MVFR VISIBILITIES.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 1001 AM CST MON FEB 6 2012/
DISCUSSION...
UPDATED THE FORECAST TO ALLOW THE DENSE FOG ADVISORY TO EXPIRE IN
EASTERN NEBRASKA...BUT EXTENDED UNTIL NOON FOR WESTERN IOWA...WHICH
REMAINS SOCKED IN WITH WIDE VISIBILITY OF 1/4 MILE OR LESS. WE ARE
SEEING AN EROSION ON THE WESTERN EDGE OF THE FOG/STRATUS...BUT IT
WILL STILL TAKE A COUPLE MORE HOURS. ALSO DROPPED TEMPERATURES IN
WESTERN IOWA WHERE THE CLOUDS WILL LINGER THE LONGEST. NO OTHER
CHANGES MADE AT THIS TIME.
WILL HAVE TO TAKE A LOOK AT EXPECTED WEATHER TONIGHT BEHIND A COLD
FRONT THAT WILL SURGE INTO THE FORECAST AREA. THIS WILL BRING LOW
CLOUDS BACK TO THE REGION...AND HAVE SOME CONCERN THAT UNTIL
DEEPER MOISTURE ARRIVES...THERE COULD BE SOME SPOTTY FREEZING
DRIZZLE IN NORTHEAST NEBRASKA FROM ABOUT 03Z-09Z THAT WE CURRENTLY
DON`T HAVE FORECAST.
DEWALD
PREV DISCUSSION... /ISSUED 733 AM CST MON FEB 6 2012/
UPDATE...
TAKING A LOOK AT LATEST OBSERVATIONS AND WEB CAMS...DENSE FOG IS
NOT PREVALENT IN OUR WESTERN COUNTIES. DENSE FOG ADVISORIES WEST
OF OUR AREA WERE CANCELLED EARLIER...SO WILL GO AHEAD AND CLEAR
WESTERN PARTS OF THE DENSE FOG ADVISORY. THE KOAX 12Z SOUNDING
SHOWED WEST OR SOUTHWEST WINDS OF 10-14 KNOTS JUST OFF THE SURFACE
SO THIS SHOULD HELP WITH THE FOG. WILL KEEP ADVISORY UNTIL 16Z FOR
EXTREME EASTERN NEBRASKA AND SOUTHWEST IOWA....
MILLER
PREV DISCUSSION... /ISSUED 520 AM CST MON FEB 6 2012/
AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
LOW CLOUDS AND FOG WILL BE THE MAIN CONCERNS AT LEAST THROUGH THE
MORNING HOURS. LIFR CONDITIONS SHOULD CONTINUE AT KOMA THROUGH AT
LEAST MID MORNING BUT SLOWLY IMPROVE TO VFR BY MID/LATE AFTERNOON.
FARTHER WEST AT KLNK AND KOFK...THE FOG WILL BE MORE VARIABLE THIS
MORNING. 13 KM RUC MODEL AND HIGH RESOLUTION RAPID REFRESH MODEL
BOTH SEEMED TO HAVE SOMEWHAT OF A HANDLE ON THE LOW CLOUDS.
WEST/SOUTHWEST WINDS SHOULD ALLOW FOR MAINLY VFR CONDITIONS FROM
MID AFTERNOON INTO THE EVENING WITH WEST OR SOUTHWEST LOW LEVEL
WINDS. IFR VSBYS COULD REFORM THIS EVENING FOR A WHILE...BUT DID
NOT MENTION AT THIS TIME. OTHERWISE...A COLD FRONT WILL PUSH
SOUTHWARD ACROSS THE AREA TONIGHT...SHIFTING WINDS TO THE NORTH.
LOOK FOR MVFR CEILINGS TO DEVELOP BEHIND THE FRONT. THERE COULD
ALSO BE SOME LIGHT SNOW OR FREEZING DRIZZLE.
MILLER
PREV DISCUSSION... /ISSUED 308 AM CST MON FEB 6 2012/
DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE EXTENT OF STRATUS/FOG AND HOW MUCH
THIS CAN ERODE THROUGH THE DAY. FOCUS THEN SHIFTS TO INCOMING
COLD FRONT AND SMALL CHANCE OF PCPN TONIGHT INTO TUESDAY.
UPPER CLOSED LOW CURRENTLY OVER THE GREAT BASIN WILL OPEN AND
CONTINUE TO PUSH EAST TOWARD THE CENTRAL PLAINS TODAY WHILE A
SHORTWAVE TROF OVER SRN CANADA MOVES SOUTH INTO THE NRN PLAINS
TONIGHT. AT THE SFC...AREA OF HIGH PRESSURE IS CENTERED OVER THE
SOUTHERN PLAINS WITH CALM WINDS OVER THE ENTIRE CWA. DENSE FOG
FORMED EARLY LAST EVENING OVER SNOWPACK AND DO EXPECT FOG TO LIFT
BY MID-LATE MORNING. STRATUS DECK OVER THE EASTERN COUNTIES IS
EXPECTED TO HANG ON THRU MUCH OF THE MORNING AND PERHAPS EVEN
INTO THE AFTERNOON HOURS AS INDICATED BY LATEST HRRR MODEL RUNS.
WL EXTEND DENSE FOG ADVISORY UNTIL 16Z AS VISIBILITIES WL BE SLOW
TO IMPROVE. STRATUS IN ADDITION TO SNOWCOVER WL PLAY HAVOC ON HIGH
TEMPERATURES. HAVE FORECAST HIGHS NEAR OR JUST ABOVE FREEZING
TODAY.
CDFNT ASSOCIATED WITH SRN CANADIAN SHORTWAVE WL MOVE INTO THE REGION
EARLY THIS EVENING AS WEAKENING SHORTWAVE ENERGY FROM GREAT BASIN
LOW APPROACHES THE AREA. LIGHT PCPN STILL ON TRACK TO DEVELOP ACROSS
KS/MO AND INTO SERN NEB. FORECAST SOUNDINGS INDICATE THE POTENTIAL
FOR LIGHT FREEZING DRIZZLE INTITIALLY AND THEN A QUICK CHANGE TO
LIGHT SNOW IF NOT JUST FLURRIES. PERIOD OF FORCING IS BRIEF AND
ONLY EXPECT LIGHT SNOWFALL ACCUMULATIONS OF GENERALLY A TENTH OF
AN INCH OR SO LATE TONIGHT INTO TUESDAY MORNING.
DRY WEATHER IS EXPECTED THEREAFTER AS SFC HIGH PRESSURE MOVES
OVER THE REGION ON WEDNESDAY. A STRONG COLD FRONT WILL SURGE SOUTH
THROUGH THE AREA LATE THURSDAY. HAVE COOLED TEMPS SIGNIFICANTLY
OVER THE WEEKEND TO ACCOUNT FOR THIS SURGE OF COLD AIR.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ043-055-056-069-
079-080-090-091.
&&
$$
99/99
AREA FORECAST DISCUSSION
NWS OMAHA/VALLEY NE
1001 AM CST MON FEB 6 2012
.DISCUSSION...
UPDATED THE FORECAST TO ALLOW THE DENSE FOG ADVISORY TO EXPIRE IN
EASTERN NEBRASKA...BUT EXTENDED UNTIL NOON FOR WESTERN IOWA...WHICH
REMAINS SOCKED IN WITH WIDE VISIBILITY OF 1/4 MILE OR LESS. WE ARE
SEEING AN EROSION ON THE WESTERN EDGE OF THE FOG/STRATUS...BUT IT
WILL STILL TAKE A COUPLE MORE HOURS. ALSO DROPPED TEMPERATURES IN
WESTERN IOWA WHERE THE CLOUDS WILL LINGER THE LONGEST. NO OTHER
CHANGES MADE AT THIS TIME.
WILL HAVE TO TAKE A LOOK AT EXPECTED WEATHER TONIGHT BEHIND A COLD
FRONT THAT WILL SURGE INTO THE FORECAST AREA. THIS WILL BRING LOW
CLOUDS BACK TO THE REGION...AND HAVE SOME CONCERN THAT UNTIL
DEEPER MOISTURE ARRIVES...THERE COULD BE SOME SPOTTY FREEZING
DRIZZLE IN NORTHEAST NEBRASKA FROM ABOUT 03Z-09Z THAT WE CURRENTLY
DON`T HAVE FORECAST.
DEWALD
&&
.PREV DISCUSSION... /ISSUED 733 AM CST MON FEB 6 2012/
UPDATE...
TAKING A LOOK AT LATEST OBSERVATIONS AND WEB CAMS...DENSE FOG IS
NOT PREVALENT IN OUR WESTERN COUNTIES. DENSE FOG ADVISORIES WEST
OF OUR AREA WERE CANCELLED EARLIER...SO WILL GO AHEAD AND CLEAR
WESTERN PARTS OF THE DENSE FOG ADVISORY. THE KOAX 12Z SOUNDING
SHOWED WEST OR SOUTHWEST WINDS OF 10-14 KNOTS JUST OFF THE SURFACE
SO THIS SHOULD HELP WITH THE FOG. WILL KEEP ADVISORY UNTIL 16Z FOR
EXTREME EASTERN NEBRASKA AND SOUTHWEST IOWA....
MILLER
PREV DISCUSSION... /ISSUED 520 AM CST MON FEB 6 2012/
AVIATION...
12Z TAFS FOR KOMA...KLNK...KOFK.
LOW CLOUDS AND FOG WILL BE THE MAIN CONCERNS AT LEAST THROUGH THE
MORNING HOURS. LIFR CONDITIONS SHOULD CONTINUE AT KOMA THROUGH AT
LEAST MID MORNING BUT SLOWLY IMPROVE TO VFR BY MID/LATE AFTERNOON.
FARTHER WEST AT KLNK AND KOFK...THE FOG WILL BE MORE VARIABLE THIS
MORNING. 13 KM RUC MODEL AND HIGH RESOLUTION RAPID REFRESH MODEL
BOTH SEEMED TO HAVE SOMEWHAT OF A HANDLE ON THE LOW CLOUDS.
WEST/SOUTHWEST WINDS SHOULD ALLOW FOR MAINLY VFR CONDITIONS FROM
MID AFTERNOON INTO THE EVENING WITH WEST OR SOUTHWEST LOW LEVEL
WINDS. IFR VSBYS COULD REFORM THIS EVENING FOR A WHILE...BUT DID
NOT MENTION AT THIS TIME. OTHERWISE...A COLD FRONT WILL PUSH
SOUTHWARD ACROSS THE AREA TONIGHT...SHIFTING WINDS TO THE NORTH.
LOOK FOR MVFR CEILINGS TO DEVELOP BEHIND THE FRONT. THERE COULD
ALSO BE SOME LIGHT SNOW OR FREEZING DRIZZLE.
MILLER
PREV DISCUSSION... /ISSUED 308 AM CST MON FEB 6 2012/
DISCUSSION...
MAIN FORECAST CHALLENGE WILL BE EXTENT OF STRATUS/FOG AND HOW MUCH
THIS CAN ERODE THROUGH THE DAY. FOCUS THEN SHIFTS TO INCOMING
COLD FRONT AND SMALL CHANCE OF PCPN TONIGHT INTO TUESDAY.
UPPER CLOSED LOW CURRENTLY OVER THE GREAT BASIN WILL OPEN AND
CONTINUE TO PUSH EAST TOWARD THE CENTRAL PLAINS TODAY WHILE A
SHORTWAVE TROF OVER SRN CANADA MOVES SOUTH INTO THE NRN PLAINS
TONIGHT. AT THE SFC...AREA OF HIGH PRESSURE IS CENTERED OVER THE
SOUTHERN PLAINS WITH CALM WINDS OVER THE ENTIRE CWA. DENSE FOG
FORMED EARLY LAST EVENING OVER SNOWPACK AND DO EXPECT FOG TO LIFT
BY MID-LATE MORNING. STRATUS DECK OVER THE EASTERN COUNTIES IS
EXPECTED TO HANG ON THRU MUCH OF THE MORNING AND PERHAPS EVEN
INTO THE AFTERNOON HOURS AS INDICATED BY LATEST HRRR MODEL RUNS.
WL EXTEND DENSE FOG ADVISORY UNTIL 16Z AS VISIBILITIES WL BE SLOW
TO IMPROVE. STRATUS IN ADDITION TO SNOWCOVER WL PLAY HAVOC ON HIGH
TEMPERATURES. HAVE FORECAST HIGHS NEAR OR JUST ABOVE FREEZING
TODAY.
CDFNT ASSOCIATED WITH SRN CANADIAN SHORTWAVE WL MOVE INTO THE REGION
EARLY THIS EVENING AS WEAKENING SHORTWAVE ENERGY FROM GREAT BASIN
LOW APPROACHES THE AREA. LIGHT PCPN STILL ON TRACK TO DEVELOP ACROSS
KS/MO AND INTO SERN NEB. FORECAST SOUNDINGS INDICATE THE POTENTIAL
FOR LIGHT FREEZING DRIZZLE INTITIALLY AND THEN A QUICK CHANGE TO
LIGHT SNOW IF NOT JUST FLURRIES. PERIOD OF FORCING IS BRIEF AND
ONLY EXPECT LIGHT SNOWFALL ACCUMULATIONS OF GENERALLY A TENTH OF
AN INCH OR SO LATE TONIGHT INTO TUESDAY MORNING.
DRY WEATHER IS EXPECTED THEREAFTER AS SFC HIGH PRESSURE MOVES
OVER THE REGION ON WEDNESDAY. A STRONG COLD FRONT WILL SURGE SOUTH
THROUGH THE AREA LATE THURSDAY. HAVE COOLED TEMPS SIGNIFICANTLY
OVER THE WEEKEND TO ACCOUNT FOR THIS SURGE OF COLD AIR.
KERN
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
IA...DENSE FOG ADVISORY UNTIL NOON CST TODAY FOR IAZ043-055-056-069-
079-080-090-091.
&&
$$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
1145 AM CST MON FEB 6 2012
.SHORT TERM...UPDATE
444 AM CST MON FEB 6 2012
HAVE MADE A QUICK UPDATE TO THE FORECAST AS SOME FLURRIES HAVE
BEEN REPORTED ACROSS THE AREA. THESE FLURRIES SHOULD END LATER
THIS MORNING AS TEMPERATURES WARM AND THE STRATUS DECK THINS OUT.
ALSO...A FEW MORE RUNS OF THE HRRR HAVE COME IN AND CONTINUE TO
KEEP THE CLOUDS IN THIS AFTERNOON...SO HAVE BOOSTED THE CLOUDINESS
A BIT MORE.
PREVIOUS AFD...
ONCE AGAIN WE ARE LEFT WITH A STRATUS DECK TO CONTEND WITH TODAY
WHICH WILL LIKELY HOLD TEMPERATURES BACK A BIT BEFORE A COLD FRONT
COMES THROUGH LATE THIS AFTERNOON AND EVENING.
A CUT OFF MID LEVEL LOW CONTINUES TO SPIN ACROSS THE CENTRAL
ROCKIES AS THE POLAR VORTEX BEGINS ITS DESCENT THROUGH EASTERN
CANADA. AT THE SURFACE...A RIDGE OF HIGH PRESSURE HAS DROPPED TO
THE SOUTHERN PLAINS WHILE A COLD FRONT IS PUSHING SOUTH ACROSS
ONTARIO AND THE DAKOTAS. MEANWHILE...A LOAN CLUSTER OF STRATUS
REMAINS TRAPPED UNDER AN INVERSION AROUND 950MB AND COVERS ALL OF
IOWA...THE WESTERN TWO THIRDS OF WISCONSIN AND THE EASTERN THIRD
OF MINNESOTA. THE 06.00Z MPX RAOB SHOWS THAT THIS LAYER OF STRATUS
IS ABOUT 200FT THICK...WHICH SHOULD BE THIN ENOUGH FOR SOME EXTRA
WIND TURBULENCE AND WARMING SURFACE TEMPERATURES TO POKE SOME
HOLES IN IT. THIS HAS NOT BEEN THE CASE OVERNIGHT DESPITE THE
INCREASING SURFACE WINDS AS THE STRATUS REMAINS A UNIFIED LAYER.
AS HAS BEEN THE CASE NOW FOR THE PAST 4 DAYS AND WHAT SEEMS THE
REST OF THIS WINTER...THE FORECAST FOR TODAY RESTS SOLELY ON WHAT
THIS THIN LAYER OF STRATUS DECIDES TO DO. IF THE STRATUS LINGERS
THROUGH THE DAY...HIGH TEMPERATURES WILL REMAIN IN THE LOW TO MID
30S. HOWEVER...IF SKIES CLEAR OUT AND BECOME SUNNY...HIGHS WILL
LIKELY REACH THE MID 40S. THE 06.00Z TO 06.05Z HRRR CEILING
PROJECTIONS HAVE ALL HAD A PRETTY GOOD HANDLE ON THE CURRENT
STRATUS FIELD AND HAVE BEEN FAIRLY CONSISTENT WITH ITS FORECAST OF
KEEPING THE STRATUS IN TACT THROUGH THE MORNING AND EARLY
AFTERNOON. THE 06.05Z HRRR RUN DID SHOW SOME HOLES STARTING TO POP
UP IN THE EARLY AFTERNOON...WHICH SEEMS PLAUSIBLE GIVEN THE
SHALLOW CLOUD DEPTH AND BETTER MIXING DUE TO AN INCREASING LOW
LEVEL PRESSURE GRADIENT AND WINDS. THEREFORE...HAVE KEPT
TEMPERATURES DOWN THROUGH THE MORNING WITH THE CLOUD COVER
EXPECTED TO AT LEAST HOLD ON UNTIL LUNCHTIME WITH A QUICK JUMP IN
TEMPERATURES THIS AFTERNOON AS HOLES START TO DEVELOP. WOULD NOT
BE SURPRISED TO SEE A FEW HIGHER TEMPERATURES CROP UP THIS
AFTERNOON...BUT CONFIDENCE IS JUST NOT HIGH ENOUGH AT THIS POINT
TO HAVE MID TO UPPER 40S IN THE FORECAST.
THE COLD FRONT ALONG THE US/CANADIAN BORDER THEN WILL ENTER THE
NORTHERN PORTION OF THE FORECAST AREA LATE THIS AFTERNOON AND PASS
THROUGH THE SOUTHERN PORTION OF THE FORECAST AREA BY MIDNIGHT
TONIGHT. SOME POST-FRONTAL FLURRIES LOOK POSSIBLE AS THE
TEMPERATURES IN THE LOW LEVEL CLOUD LAYER DROP TOWARD -10C
TONIGHT. THE 06.00Z NAM/GFS/GEM ALL HAVE SOME SPOTTY QPF THAT
SHOWS UP TONIGHT WHICH IS LIKELY A RESULT OF A SLIGHTLY DEEPER
DENDRITIC GROWTH ZONE THAT TRIES TO DEVELOP BETWEEN 900-750MB. THE
ONLY FORCING WITH THIS SYSTEM IS WITH SOME WEAKLY SLOPED
FRONTOGENESIS WITH THE MID LEVEL TROUGH LAGGING FAR BEHIND.
THUS...AM NOT TOO HIGH ON THE CHANCES FOR GETTING AN ACCUMULATING
SNOW OUT OF THIS FEATURE.
BEYOND THIS IT WILL JUST BE A QUESTION OF WHEN SKIES CLEAR OUT AS
A RIDGE OF HIGH PRESSURE SETS UP ACROSS THE PLAINS AND GREAT LAKES.
THIS RIDGE WILL DROP TEMPERATURES DOWN TO SEASONAL LEVELS GOING INTO
MID WEEK WITH THE CLEARING LIKELY TAKING PLACE ON WEDNESDAY.
.LONG TERM...THURSDAY NIGHT THROUGH SUNDAY
257 AM CST MON FEB 6 2012
THE MAIN FOCUS IN THE LONG TERM CONTINUES TO BE WITH WHEN A COLD
FRONT WILL DROP DOWN AND HOW COLD WILL IT GET LATE IN THE WEEK
AND WEEKEND. IT APPEARS THAT THE 06.00Z GFS AND ECMWF HAVE
FINALLY COME TO A COMPROMISE WITH BRINGING A NORTHEAST TO
SOUTHWEST ORIENTATED COLD FRONT THROUGH THE REGION THURSDAY
AFTERNOON AND EVENING WITH NO PRECIPITATION OCCURRING IN THE
REGION. TEMPERATURES WILL COOL TO BELOW NORMAL WITH 850MB
TEMPERATURES DROPPING TO -20C FOR A PERIOD THURSDAY NIGHT INTO AT
LEAST FRIDAY. THE 06.00Z ECMWF IS A BIT FASTER WITH BRINGING
WARMER AIR BACK IN AT THE LOW LEVELS ON SATURDAY ALREADY WHILE THE
06.00Z GFS HOLDS ONTO THE COLDER AIR FOR LONGER. THUS...HAVE GONE
WITH THE COLDER TEMPERATURES THURSDAY THROUGH SATURDAY WITH A
WARMING TREND SUNDAY.
&&
.AVIATION...THIS AFTERNOON THROUGH TUESDAY
1145 AM CST MON FEB 6 2012
PIREPS FROM THIS MORNING INDICATED CLOUD DECK WAS ON THE ORDER OF 1K
TO 1.5K FT THICK...THUS INCREASED FORCING/MIXING WITH WEST/SOUTHWEST
WINDS AHEAD OF THE FRONT DROPPING THRU MN HAS BEEN ENOUGH TO BREAK
UP/ERODE THE MVFR/IFR STRATUS OVER PARTS OF THE AREA. VIS IMAGERY
SHOWED CONTINUED EROSION OF THE CLOUDS WEST OF THE FCST AREA LATE
THIS MORNING...THUS TRENDED KRST/KLSE TAFS MORE OPTIMISTIC FOR THE
AFTERNOON HOURS...WITH VFR VSBYS AND THE LOW CLOUD LAYER BECOMING
SCT. SFC FRONT STILL DUE IN AROUND 00Z WITH A WIND SHIFT TO THE
NORTHWEST. HOWEVER NEXT MAINLY MVFR STRATUS DECK LAGS THE FRONT BY A
FEW HOURS AND DELAY ARRIVAL OF THESE CLOUDS INTO KRST/KLSE UNTIL
03Z. THIS MOISTURE RATHER SHALLOW AND REMOVED -SN/FLURRY MENTION
UNTIL LATER TONIGHT WHEN DEPTH OF MOISTURE LOOKS TO INCREASE TO
ABOUT 2KM ALONG WITH SOME WEAK FORCING/LIFT. BY LATE TONIGHT WHEN
MOISTURE IS DEEP ENOUGH CLOUD-TOP TEMPS PROGGED TO BE IN THE
-10C-12C RANGE...COLD ENOUGH FOR ICE IN THE CLOUDS AND PRECIP AS
FLURRIES. HOWEVER...IF CLOUD TOP TEMPS END UP MORE -8C TO -10C...
THREAT WOULD EXIST FOR PATCHY FREEZING DRIZZLE...BUT POST FRONTAL
AIRMASS AND ANTI-CYCLONIC LOW LEVEL NOT FAVORABLE FOR A DRIZZLE
SCENARIO AND LEFT THIS MENTION OUT FOR NOW. MOISTURE ONCE AGAIN
BECOME SHALLOW UNDER AN INVERSION NEAR 900MB BY LATER TUE MORNING.
FURTHER DRYING EXPECTED IN THE 950-900MB LAYER FOR TUE AFTERNOON
WITH CLOUD DECKS LOOKING TO BECOME SCT AFTER 18Z TUE.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
257 AM CST MON FEB 6 2012
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
SHORT TERM...HALBACH
LONG TERM....HALBACH
AVIATION.....RRS